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EPA
This is not an official policy and standards document.
The opinions, findings, and conclusions are those of the authors
and not necessarily those of the Environmental Protection Agency.
Every attempt has been made to represent the present state of the art
as well as subject areas still under evaluation.
Any mention of products or organizations does not constitute endorsement
by the United States Environmental Protection Agency.
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J'''Il PRO"l~v
AIR POLLUTION TRAINING INSTITUTE
MANPOWER AND TECHNICAL INFORMATION BRANCH
CONTROL PROGRAMS DEVELOPMENT DIVISION
OFFICE OF AIR QUALITY PLANNING AND STANDARDS
n
The Air Pollution Training Institute (1) conducts training for personnel working on
the development and improvement of state, and local governmental, and EPA air
pollution control programs, as well as for personnel in industry and academic insti-
tutions,' (2) provides consultation and other training assistance to governmental
agencies, educational institutions, industrial organizations, and others engaged in
air pollution training activities,' and (3) promotes the development and improve-
ment of air pollution training programs in educational institutions and state, regional,
and local governmental air pollution control agencies. Much of the program is now
conducted by an on-site contractor, Northrop Services, Inc.
One of the principal mechanisms utilized to meet the Institute's goals is the intensive
short term technical training course. A full-time professional staff is responsible for
the design, development, and presentation of these courses. In addition the services
of scientists, engineers, and specialists from other EPA programs, governmental
agencies, industries, and universities are used to augment and reinforce the Institute
staff in the development and presentation of technical material.
Individual course objectives and desired learning outcomes are delineated to meet
specific program needs through training. Subject matter areas covered include air
pollution source studies, atmospheric dispersion, and air quality management. These
courses are presented in the Institute's resident classrooms and laboratories and at
various field locations.
-f<.Lk J::>. ))./~
Robert G. Wilder
Program Manager
Northrop Services, Inc.
~
Chief, Manpower & Technical
Information Branch
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Contents
SECTION ONE
Classification and Definition of Atmospheric Pollutants
Control of Industrial Emissions
Control by Raw Material and Process Change
SECTION 'NO
Introduction: The Collection of Particles from a Gas Stream
Introduction: Collection Equipment
~10t Collection Equipment
.3fTTION THREE
Characteristics of Particulate Matter
SU~TI()N POUR
All About Cyclone Collectors
Prirrcr on Fabric Dust Collectors
FulJric Filtration
I~lectrostatic Precipitators
~)EC!'roN FIVE
All About Wet Collectors
Gravity Spray Tower
Impingement Type Scrubbing Tower
Collectors with Self-Induced Sprays
Disintegr>ator Scrubbers
Wet Centrifugal Collectors
Venturi Scrubbers
SECTION SIX
Control of Vapors and Gases
SEC--rroN SEVEN
Control by Combustion
:';ECTION EIGHT
Ak50rbcrs
A Guide to Scrubber Selection
Absorption Equipment: Selected Applications
.sECTION NINE
I\a;.:;ic: Concepts of Adsorption on Activatc'Ci Carbon
l~inciples of Adsorption
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:;r~C'I'TON TEN
J.lquld Industrial Wastes
Wa:-;V'w::ller Reduction
:;L<.:Cl'ION ElEVEN
Economics of Pollution Control System
I~oduct GUide/1972
::I':Cl'ION 'I'WELVE
Lndustrial Odor Control and Its Problem
I ndu;;t1'lal ()jor Control
(;, >nlrol Methods for the RelOOval of Sulfur Oxides from Stack Gasc~~
1\ L1' Pollution: The Control of S02 from Power Stacks
Control of NOic Elnissions frOOI Stationary Sources
1\1'1 lJulletin Evaporation wss in the Petrolewn Industry--Causcs and Control
I'Jwi ['orlITlf'ntal Pollution Control at Hot Mix Asphalt Plants
Kraft I'ulpinr; Process
(;<>III-r'o L of Particulate I1nissions From L1~ Plants
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Questions
AIR POLLUTION CONTROL TECHNOLOGY
DIRECTIONS: Put your name on the Answer Sheet which is attached to the
back of the test. For each question, circle the correct answer on the
Answer Sheet. There is only one correct answer to each auestion.
I - 25 are TRUE-FALSE
I.
Most particulate control devices were developed to abate air
po I I uti on.
"
~ .
Catalytic Afterburners operate at a higher temperature than
Flame Afterburners.
3.
Basically, regenerative activated charcoal adsorption systems
are used where the concentration of pollutants in the gas strea~
i3 high.
4.
Extremely high collection efficiencies are required for most equipment
used to control odors, since odors can be objectionablp at very low
concentrations.
5.
fligh efficiency cyclones are generally those with a bo('y diameter
of less than nine inches.
t"
fur (J cyclone, most design changes which
tend to increase the pressure drop.
i ncr'~ase et t i (: i ency a I so
7.
The main advantage of an electrostatic precipitator over a bag h0use
is that an electrostatic precipitator does not have a large space
requirement.
8.
The most commonly used type of control equipment on asphalt batching
plants in the U.S. is the electrostatic precipitator.
P A . C . pm. 105. 'J . l3
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-2-
9.
Settl ing chambers are mainly used to decrease the load on a
secondary .co II ector.
10.
Sulfur dioxide emissions are usually control led effectively by
scrubbing with water.
II.
The efficiency of an adsorption system can be increased by
increasing the temperature.
12.
In flare type combustion devices, steam is injected to promote
turbulence.
I S.
Nitrogen oxide formation (NO and N02) from combustion can generally
be reduced by decreasing the temperature or pressure in the combustion
chamber.
14.
Water qual ity standards
initial design of a wet
waste may take the cost
method of control.
should be kept in mind even before the
col lector, since treatment of the resulting
of pollution control higher than some other
15.
Increased velocity in the rotary ki In of an asphalt plant wi I I
increase output whi Ie decreasing emissions.
16.
Electrostatic precipitators wi I I remove odors by causing an
electrical arc which breaks down the aromatic hydrocarbons.
/ 1.
Venturi Scrubbers wi II remove a high percentage (98%) of particles
below the .01 micron range.
/8.
The automobile is the major source of nitrogen oxides and hydrocarbons
both of which are the principle reactants in the formation of Photo-
chemical Smog.
19.
The electrical equipment for an electrostatic precipitator includes
a rectifier to transform the alternatinq current (AC) voltage to
direct current
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-3-
20.
High temperature fabric filtration Is accomplished with glass fabrics.
21.
Air injection, Catalytic and Flame after burning, and engine modification
are methods which can be appl led to Automotive exhaust control
22.
Rapping of electrodes in electrostatic precipitators consists of covering
the electrodes in corrosion-resistant foi I.
23.
A large problem in control of emissions from ferti I izer plants is due
to corrosion from hydrofluoric acid and phosphoric acid.
24.
When Potentials as high as 70,000 volts are used on electrostatic
precipitators, it is possible to achieve 90% removal of particles
5 mi~rons ~ size.
25.
Masking and counteraction is the only technique for treating odorous
materials from rendering plants' vapors.
0uestions 26 - 45 are MULTIPLE CHOICE
26.
Any device which removes particles by causing impaction on a target
due to a sudden change in the direction of the gas stream can be
ca I I ed an
(a)
( b)
(c)
( d )
Electrostatic precipitator
Venturi scrubber
Bag f i Iter
Inertial separator
27.
The principle source(s) of gaseous emissions from automobiles are
(a) Exhaust
(b) Exhaust, crankcase, and carburetor
(c) Exhaust, crankcase
(d) Exhaust, crankcase, carburetor, and fuel tank
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-4-
28.
An act i vated so lid "adsorbent" Is character i zed by
(a)
(b)
(c)
(d)
A low retention time of adsorbate
Low density
High surface area per unit mass
Large particle size
29.
Vapors from Rendering plant cookers usually are pretreated before
incineration. The pretreatment process is
(a)
(b)
Condensation of moisture
Activated carbon adsorption
Pass through venturi scrubber
None of the above
(c)
(d)
30.
The actual physical diameter of a particle can be directly determined
with a(n)
31.
(a)
(b)
(c)
(d)
Optical microscope
Cascade impactor
Dustfa II bucket
None of the above
Efficiency of an electrostatic precipitator increases with a
decrease in
32.
(a)
(b)
(c)
(d)
Collection electrode area
Migration velocity of the particles
Charge on the discharge and collecting
Gas f low rate
electrodes
The basic requirements for complete combustion of a combustible
gaseous pollutant are
(a)
( b)
(c)
(d)
Turbulence and oxygen
Turbulence, temperature, retention
Oxygen and less than 5% moisture
None of the above
time, and oxygen
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-5-
33.
Which of the fol lowing factors most limits the usefulness of fabric
fi Itration as a means of contror----
(a)
(b)
(c)
(d)
Abrasion
Temperature
Flow rate
Fabr ic th i ckness
34.
Catalytic incineration is unsuitable in some instances due to
(a)
(b)
Low combustible concentrations in the gas
Compounds such as lead and mercury, which wi I I
poison the catalyst
Reaction of the catalyst with select inert gases
None of the above
(c)
(d)
35.
Asphal t plants generally do not use wet co I lectors as primary
col lectors because
(a)
( b)
Wet col lectors would excessively reduce the emissions
Asphaltic oi Is are immisible in water
The particulates in the gas would erode the col lector
It is difficult to recover the fines when they are in
a slurry state.
(c)
(d)
Two distinct mechanisms of particulate removal are uti I ized in the
Fabric Fi Iter. The first is fiber fi Itration where the dust is
retained on the fibers themselves, and the second is
fi Itration, where the dust layer removes additional particles.
36.
(a) Cake
(b) Congealed
(c) Pi
(d) None of the above
37.
The difficulty of separation by the absorption process is increased by
(a)
(b)
(c)
(d)
Decreased temperature
Increased concentration of absorbate
Low sol ubi I ity of absorbate
Use of packed tower rather than spray
scrubber
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-6-
38.
The flare type of combustion control device is most appl icable for
gases with
(a)
(b)
(c)
(d)
Periodic releases of low concentration
Steady releases of high concentration
Periodic releases of high concentration
Steady releases of low concentration
39.
The absorption equipment most used In air pollution control of gaseous
pollutants is the
40.
(a)
(b)
(c)
(d)
Spray scrubber
Plate tower
Packed tower
Venturi
A thin bed adsorption system is characterized mainly by
(a)
(b)
(c)
(d)
High power consumption per cfm
Low concentration of adsorbate in
High pressure drop
High collection efficiency
the gas
Since the efficiency of a venturi is directly related to Inertial
parameters, which of ,the fol lowing operating conditions may be
varied to give the greatest Increase in efficiency?
41.
42.
(a)
Increase the throat velocity and reduce the
liquid injection rate
Increase the liquid density and decrease the
liquid Injection rate
Increase the droplet size and decrease the
number of droplets
Increase the throat velocity and Increase the
number of droplets
(b)
(c)
(d)
If a particulate control device has a collection efficiency of 50%, this
genera II y means
(a)
(b)
(c)
(d)
The device wi I I remove
The device wi I I remove
of particulate matter
Either (a) or (b), since they mean the same thing
None of the above
50% of the particles
50% of the total weight
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~7-
43.
In a cyclone col lector, the particulate matter moves rapidly to the
sides of the col lector. ThIs movement is due to which of the fol lowing
forces?
(a) Centrifugal
(b) Centripital
(c) Gravitational
(d) Van der Waals
44.
The principle adsorbent used in control I ing organic vapo~s is
(a) Activated charcoal
(b) Water
(c) S i I i ca gel
(d) None of the above
45.
In the most common type of absorption system, the flow is
(a)
(b)
(c)
Co-current
Counter-current
Cross-f low
(d)
Random
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NAME
ANSWER SHEET
I. T F 16. T F 31. a b c d
2. T F 17. T F 32. a b c d
3. T F 18. T F 33. a b c d
4. T F 19. T F 34. a b c d
5. T F 20. T F 35. a b c d
6. T F 21. T F 36. a b c d
7. T F 22. T F 37. a b c d
8. T F 23. T F 38. a b c d
9. T F 24. T F 39. a b c d
10. T F 25. T F 40. a b c d
II. T F '26. a b c d 41. a b c d
12. T F 27. a b c d 42. a b c d
13. T F 28. a b c d 43. a b c d
14. T F 29. a b c d 44. a b c d
15. T F 30. a b c d 45. a b c d
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AIR POLLUTION CONTROL SYSTEMS
You have been called in by Acme Corporation as an air pollution
control consultant to solve the company's particulate emission problem.
Tommorrow you are to present the results of your study and your recom-
mendations to the Board of Directors.
Since the directors at Acme Corporation are extremely thrifty
and skeptical men, as part of your presentation it will be necessary
for you to:
1.
Define the problem.
2.
Examine the feasibility or nonfeasibi lity
of inertial collection, wet collection,
electrostatic collection or fabric
f i 1 t rat i on .
3.
Select the best control device or system
that will maximize effectiveness and
minimrze costs.
You must state any assumptions used and discuss disposal of
collected particulate emissions. Diagrams should be used when
possible.
rA.C.pm. 106.5.73
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PROBLEM I.
Asphalt Batching Plant
Acme Corporation is supplying the City with hot asphalt to
resurface the city streets. The equipment is located on two vacant
lots in the downtown area of the city.
term lease on the lots.
The company has only a short
We know from our test that hot asphalt batching plants are spurces
of heavy particulate emissions. The asphalt batching process involves
the mixing of hot, dry sand, aggregate, and mineral dust with hot asphalt.
The major source of air pollution is the direct-fired dryer (rotary
dryer) used to dry and heat aggregates. Other sources are the bins,
the aggregate weight hopper, and the mixer.
In this operation the rotary dryer emissions have been measured at
6,700 pounds per hour, as shown in the table (1).
Also in this plant,
2,000 pounds of dust per hour were collected from the discharge of the
secondary dust sources; that is, the vibrating screens, hot aggregate
bins, the aggregate weight hopper, and the mixer (vent line). Dryer dust
emissions
increase with air mass velocity, increasiny rate of rotation, and
feed rate, but are independent of dryer slope. Particle size distribution
of the dryer feed has an appreciable effect on the discharge of dust.
Tests show that 55% of the minus 200-mesh fraction in the dryer feed can
be lost in processing. The percent dust emissions from the secondary
sources vary with the amount of fine material in the feed and the mechanical
condition of the equipment.
In this case Table 1.
gives thc results of
the dust and fume discharge test.
1 )
Select a method of control, describe the control equipnlc!1t,
show its location, and give its collection efficiency and
particle size removal.
2)
Does the above method meet the local control regulations?
(See attached regulations)
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7.18.4
CYCLONE (a)
f.A6uu~~ST.L.A~EN. GASES.
SUCK.
Imr. 1
\ 'Tm'
.1 I
i.
V lEI GH
HOPPER :
(b) :
o
.
~
b...
NOT AGGREGATE
IUCKET ElEVATOR
(a)
(b)
(c)
.
Primary Collector
Secondary Collector
Mineral Filler & Asphalt Cement Added at Mixer
Emission Points
Figure 7.18.2.
FLOW DIAGRAM OF A TYPICAL HOT-MIX ASPHALT PAVING BATCH PLANT
(SOURCE: Danielson, Reference 2)
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Table 1
DUST AND FUME DISCHARGE FROM ASPHALT BATCH PLANTS
--.-------- ---.---------
------- . ----------------- .--
rest No.
Batch plant data
Mixer capacily, Ib
Process weight, Ib/hr
Drier fuel
Type of mix
Aggregate feed to drier, wt %
tlO mesh
-10 to +100 mesh
-100 to t200 mesh
-200 mesh
--
Dust d!H1 fmne dala
Ga3 volume, seLIn
Gas temperature, of
Dust loading, Ib/hr
Dust loading, grains/sd
Sieve analysis of dust, wt %
+ 100 me>Jh
-100 to +200 mesh
-200 mesh
P,,-rticle size of -200 mesh
o to 5 fl, wt %
5 lo 1 0 ~, wt %
J 0 to 20 fl, wt %
20 to 50 fl, wt %
> 50 11, wt %
__n_.__'_~
------------.. ---------
-----
--------.-----
-- -----.---------
----------
C-.1!.6
C-537
--------
6,000
36.1,000
Oil, PS300
City stn'et, surface
6,000
346,000
Oil, PS300
lIighway, surface
70.8 68. I
24.7 28.9
1.7 1.4
2.8 1.6
Vent linea Drier Vent linea Drier
2,800 21,000 3,715 22,050
215 180 200 430
2,000 6,700 740 '1,720
81.8 37.2 23.29 24.98
4.3 17.0 0.5 18.9
6.5 25.2 4.6 32.2
89.2 57.8 94.9 48.9
19.3 10. I 18.8 9.2
20.4 11. 0 27.6 J 2.3
21. 0 II. 0 40.4 22.7
25. I 21.4 12. I 49.3
14.2 46.5 1. I 6.5
aYf'nl line sC'rvf'S ho' C'levator, screens, bin, weigh hopper, and mixer.
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ADMINISTRATIVE REGULATIONS
AIR POLLUTION CONTROL COMMISSION
CHAPTER 16-20
Series II I
Subject:
Rcgu1atiQn III - To Prevent and Control Air Pollution From the Operation
of Hot Mix Asphalt Plants.
Section 2.
Emission of Smoke Prohibited and Standards of Measurement.
2.01. No person shall cause, suffer, allow or permit emission of smoke into
the open air from any fuel burning equipment which is as dark or darker in
shade or appear"ance as that designated as No.1 on the Rin~eli1ldnn Smoke Chart.
2.02. The provisions of Subsection 2.01 of this Section shall not apply to
smoke emitted during the starting operation the shade or appearance of which
is less than No.3 of the Ringelmann Smoke Chart for a period or periods
aggregating no more than 4 minutes per start-up.
2.03. The equivalent opi3city of those Ringelmilnn numbers in SIJbsection 2.01
and Subsection 2.02 of this Section shall be used as a guide in lhe enforce-
ment of Section 3 of this RegulJtion.
Section 3.
Control and Prohibition of Particulate Emission.
-----
3.01. (:0 person shall cause, suffer, allow or permit particulate emission
fn;.11 d pliJnt into the opcn air iil cxce<;s of the Cjuantity as listed in the
following table:
Aggregate Process Rate
Pounds Per Hour
Stack Emission Rate
Pounds Per Hour
-~--
10,000
20,000
30,000
40,000
50,000
100,000
200,000
300,000
400,000
500,000
600,000
10
16
22
28
31
33
37
40
43
47
50
For a process weight between any two consecutive process weights stated in
this table, the emission limitation shall be determined by interpolation.
3.02. In the case of more than one stack to a hot mix asphalt plant, the emis-
sion limitation of Subsection 3.01 of this Section will be based on the total
emission from all stacks.
3.03. No person shall cause, suffer, allow or permit a plant to operate that
is not equipped I"ith a fugitive dust control system. This system shall be
operated and maintained in such a manner as to prevent the emission of partic-
ulate material from any point other than the stack outlet.
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PROBLEM II.
Electric Power Plant
Power is generated for Acme Corporation by one central power plant
built in 1952. The plant has a capacity of 135 mcgav'.,Iatts. At full load
the boiler unit produces approximately 950,000 pounds of steam per hour
at 1,900 psi and 1000°F. The power plant burns approximately 1,200 tons
per day of 3% sulfur and 12% ash content coal. (Assume the coal has a
heating value of 10,000 BTU/lb.) The flue gas, after passing through
the air heater, is divided into two parallel ducts and drawn through by
two 300,000 cfm induced draft fans. The gas is then released through
a brick-l ined, ISO-foot steel stack.
Recent checks show little or no control for removal of particulates.
1)
Select a method of fly-ash control, describe the contr01
equipment, show its location in the system. and Qive its
collection efficiency and particle size removal. The
power plant out! ine is shown in Figure 2.
2)
Will this control method meet the Federal Performance
Standard of 0.1 lb/106 BTU of heat input?
3)
Comment on the degree of control required to meet the
Federal Performance Standard of 1.2 lbs. of S02 per
106 BTU of heat input?
-------
1------
t .--
!
I
I
I
!--
\ -----.---
Coal bu k
n er
,.::--,.
i ..-)
1
, ' Sampl'
I -;;»'----. lng points A
i. 0 ~
Stack
(~Drum Seco d \
( L n a,y .
/-;-,<~ jsuperheater
. II \}
1(-' L/~h~a'e< !
S~mpling III' \ i 1;1 ~~ S I
II point,,: ~ ! . , :; i \ - uperheater I
K I ,__i : : ; lJ/ - t and reheater I
i' ,-,-,,' C-_:---~_." in parallel!
Sampli /1:; ,,/,11 -- ----:;! /! : t
I ng 1'- -,' .< "" I
poin t .,/ I '- ,:-' ~::-::-- .. -,' I I
H ' l..... i C ':.- ,:: I c
.:.. --..--:::::
~.-_~-I !
, --.-~' !
C:,:'-;_:": >,Ec' !
c.'i--'-:-~'=-ll onomlzer I
-. - ';;'("-]- "~.:J Sampli I I S
ng /v amplin
points F .,,0 -, Poi g
r-' . , nts, B
I 1
Ii i: t F D f
I - ,,' . an
I' ,or --'-
/~'J-'::i'" ~) ')
.,; "{ ,J
~~~n::-~j
~.--,' rculating fan
Pulverizer
POWER P
LANT Fi gu re 2
-------
MISCELLANEOUS INFORMATION
Maximum load Factor:
1.01 - 1.02 (of design capacity)
Daily Average Load Factor:
0.80
Typical Efficiency:
9000 BTU/kw hr.
0.2 of Total Ash Drops Out in the Ash Pit
Typical Emission Factors (lb/ton coal burned):
Particulate -- (16) x (% Ash)
Sulfur Oxides -- (38) x (% Sulfur)
TABLE
2.
Size Distribution For Particles Emitted From
A Pulverized-Fuel-Fired Furnace
Particle Size Range, ~
% of Total Weight
0-5
5 - 10
10 - 20
20 - 30
30 - 40
40 +
25
20
15
15
10
15
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PROBLEM III.
Municipal Incinerator
Preliminary results of a survey conducted by Acme indicated that
the incinerator should remain in use if the smoke and particulate air
pol lut ion can be controlled.
This incinerator is located on a smal I
comme r cia 1 lot.
I t is of a Class V by the Incinerator Institute for
knerica's standard.
I t is suitable for burning, rubbish, refuse, and
garbage. In the survey it was noted that about five pounds per capita
per day were collected for disposal in this city of 150,000 population
In a recent test the data showed emissions to be 2,000 pounds per
day of SO , and 6,000 pounds per day of particulates. At the present
x
time no auxil iary burners are being used in the mixing chamber.
HO\\'ever. a total of 150 percent excess air is sometimes supplied to
promote oxidation of combustibles.
~ack emissions of smoke and
particu]ates must be limited to meet the air pol lution codes.
I )
Select a method of control, show its location in the
system, and give its collection efficiency and particle
size removal. Figure 3 shows a section of the municipal
incinerator.
2)
Wil I this method meet the Federal Performance Standard
of 0.08 grains of particulate per SCF, corrected to
12% C02? (This would correspond to approximately
4 lb/hr.)
-------
TABLE
3.
Size Distribution For Particles Emitted From
A Municiple Incinerator
P~rticle Size Range, ~
% of Total Weight
0-2
2 - ,.
,. - 10
10 - 15
15 - 20
20 - 30
30 +
17
5
8
3
3
5
59
-------
o
.
" "-: ',); . - ..~ - - ~(~ e<\)\'. '<,
....\ .,.~'~ ,1 '''\~i' .~ ~'," y i.
,." .., . '"', ",..".' '.111.
I" ., " '1 ~ ,.;.~.. W
~,. '.~ f~ _,I, . . ( ;:~~...~t!-
',--
1. INCINERATOR
2. STORAGE PIT
3. GRAB BUCKET
4, BRIDGE CRANE
S. CHARGING HOPPER
6, HOPPER GATt
7. WATER.COOLED HOPPER
8. FEEDING AND DRYING STOKER
9. BURNING STOKER
10. PRIMARY COMBUSTION CHAMBER
11. SECONDA RY COMBUSTION CHAMB E R
12. GAS.CLEANING CHAMBER
13. FLUE
14. DAMPER
15. CHIMNEY
16. ASH CONVEYOR
17. FORCED.DRAFT FAN
18. REFRACTORY ENCLOSURES
figure 3.
Schematic of Typical Municipal Incinerator.
I
-------
PROBLEM IV.
Cement Plant
Acme Corporation has a large cement plant which is discharging
from its stack 150 tons of gas-borne dust into the outdoor air every
24 hours. The Air Pollution Control Agency said this plant must
reduce its dust load to 500 pounds per day or less. This plant is
a 2.)- million barrel-a-year plant. You have C"Jn ambient air pollution
problem when bulk tank trucks or railroad cars are being loaded and
when the cement is pumped to and from si los.
In a test you found that 800 pounds of fine dust were being
emitted with the displaced air in the filling of one si 10 (bulk
storage bin). I-bwever, the hot kiln gases which contain pulverized
raw and partly burned calcareous and argillaceous particles in high
tonnage present the major problem due to the fact that the gas volume
is greater than a quarter of a million cubic feet per minute and
contains acid gases of hydrogen sulfide and sulfur dioxide and varying
amounts of water at a temperature of 600°F.
This combination of conditions may require the scalping of larger
particles, above ten microns. It has been said that you can scalp off
about 70% by weight of all of the coarser particle size fraction and
have a reduction at the kiln from 150 tons to 45 tons per day.
I t has
been demonstrated in the industry that a draught fan wi 11 not last many
months without scalping.
1) Select a method for particulate con t ro 1, sholv its locat ion
in the system, and state its efficiency. The flow chart
shows steps in the manufacture of cement and Table 4 gives
the particle size distribution from the plant.
2)
Will this system meet the Federal Performance Standard
of 0.40 lblton of feed?
-------
7.10.2A
lAW MATElIALS CONSIST OF
COMBINATIONS OF LIMESTONE.
CfMENT lOCK, MAIL 01 OYSTU SHELLS,
AND SHALE, eLA.,. SAND, 01 IRON OlE
STONE IS FIRST REDUCED TO 5-IN. SIZE, THEN %.IN.. AND STORED
1
RAW MATERIALS ARE GROUND TO POWDER AND BLENDED
VIU"YlNG
se'UN
.. IrE I
:'II)I~~J_'
. ~~.
lAW MAtERIALS 1:-
ARE P.OPOUIONED
nUll'
PUM'S
StUll., 15 MIXED AND 8UNDI:D I'
StUll'
rUM'
STORAGE I"SINS
RAW MATERIALS ARE GROUND. MIXED WITH WATER TO FORM SLURRY. AND BLENDED
2
Figure 7 .10.1.
PROCESS STEPS--PORTLAND CEMENT PRODUCTION
(SOURCE: PORTLAND CEMENT ASSOCIATION, Reference 3)
J
-------
.
lAW MIX IS KILN IUINED
TO 'AITIAL FUSION AT 2700. F.
7.10.2B
~.
MA TERrALS AlE
STOIED SEPAU TEL Y
CLiNKEI
o
~
~
.
,
o
GYPSUM
..~.:~~."':.~ - C' .
FAN
DUST
IIN
IOTA TING KILN
BURNING CHANGES Rf>,.W MIX CHEMIC;::ALL Y INTO CEMENT CLINKER
A'I
SE'AIATOI
'~-tIJj'!;~~V~
~ "~ ." ..<..~\t\
. . .. O'~
r.\~
o-'t>. -r.v ~
~,) (J] ~
C;;::~<.'
...,,,,,, '''lJ'1' .;,-;c., ..t...,..:;."Ult.
PROPORTIONED .,., - "f. "..~ .~..._...- . --
GIINDING MILL
CIMINT
PUM'
3
IULK STOIAGE
(J 0
'AexAGINO
MACHINE
TRUex
IULK
TIUCK
IULK
CAI
CLINKER WITH GYPSUM ADDED IS GROUND INTO PORTLAND CEMENT AND SHIPPED
lOX
CAI
Figure 7.10.1.
4
(SOURCE:
PROCESS STEPS--PORTLAND CEMENT PRODUCTION (continued)
PORTLAND CEMENT ASSOCIATION, Reference 3)
-------
TABLE 4.
SIZE DISTRIBUTION OF DUST FROM A CEMENT PLANT
Particle Size Range. ~
% of Total Weight
o - 2.5
2.5 - 5.0
5.0 - 10.0
10.0 - 20.0
20.0 - 30.0
30.0 - 40.0
40.0 +
15
8
12
23
17
14
11
-------
PROBLEM
V.
Acme Corporation has completed a particle size analysis on
emissions from its Tootsie Role manufacturing process. The particle
size distribution is presented in Table v. The plant is current~y
emitting 500 Ibs/hr. This must be reduced to an allowable emission
of 25 Ibs/hr.
1)
Is it possible to install a gravity spray tower
coupled with self-induced sprays? (See efficiency
curves.)
2)
What is the efficiency of each collector?
3)
What is the total system efficiency?
4)
What would be the overall efficiency of a Venturi
scrubber by itself?
5)
Which of the two systems would you recommend using?
TABLE V.
Particle Size Range
% of Total Weight
0-2
2 - 4
4 - 6
6 - 10
10. - 20
20 - 40
40 +
10
20
2S
20
15
S
5
-------
PROBLEM
VI.
Another Acme plant manufactures widgits.
Acme's widgit
plant puts out 500 Ibs/hr of particulate as does its Tootsie
Role plant (see Problem V). This plant must also reduce
emissions to 25 Ibs/hr. The particle size distribution for
widgit manufacturing appears in
required in Problem V using the
widgit manufacturing.
Table VI. Repeat the analysis
particle size distribution for
TABLE V I .
Particle Size Range
% of Total Weight
0-2
2 - 4
4 - 6
6 - 10
10 - 20
20 - 40
40 +
25
30
25
10
5
5
o
-------
I [~:-r:~=:- Jl""::l- =---I~J[-J 1,-- II -I ,-I
I 'M,,,,,,""~'!' 'r'"'''''' (' 'I <- ~l ~ ~.~---x L,,,,,- . .' . Y" ,., J
--r ~ ~--- .-""'"'''''''' D''''':il",''~-~J .+_._In.
~.-- ~. --i""" ."".1, "i""_~': I...
Amm'Ji,'um Chloride ~:':~-- -!~-hund~.J_J --'>
A!L, Jnos ;~;a~t~:~:,~u~~'~1 'crL: u..",J .1
~--I" '--Ilr~'i,:;'e. PUIP:r,',,:Ct::,- .. ,- "1
I -1 --['-'---'.' - ... ... ,- . I
,.. ~eifuric ".c~d Misl -0- I
. ""'-f~-~L.en, D:~;2.._...:. I
! I, ZinC OJi1e femes I CZ~~~.~~~f <1- pu,vLJC0o' .J "
I I r-lT ~ L":;:~Du,tS /1::n~S~~$ 1'- ----
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1"lllH ~- T--I'> I I
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:"(u I I I I I I I
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, I ~ 4----> I
- 511v" I "d. ide -. . -~---r }pra:. ~'icl~~;:- I "
1- .l~. ,- C,::"""" ""'";. I -- --""',"-,""~..",i,'.. _....' I
I ~,:,:;:~:":'::::~ J ~-,-"",'" - "'\W,;" { -.---.[. +-"",,1, l~.__. -- -: ._1
j l n~~;:I;I'~"tc'es Ie" h 400 ,}S :'0,. leD", .~~:;J ~., JJ I'
' -- - .-------- J ~ole,01 ",°5 ~--'r-' ...~.'. -'.. C -',
l_...~..~- ~l-- C--._L_--_- ___J:S;TIC_LL~~,.[2:C1)L l_d____l--.L_._.J.__L'___'Ul .!
o u:.jl C 00 J:' a 'JUI 0.u:J5 0.01 J.CS 0.l''' 0.5 1 5 jQ ~ jC-J ~..) J,v:O 5,:'- , : .
(Chart r('p~od'.!c .'d h~' C'ourt~sy of 1.~i;le S:,ff'ty l,p,-;li:l:lce~ ('C;:P1ilV).
The Size of Air-Borne CC.lt:'Iflin:.n\ s
Figure 1.
I I
II
I
I
-------
100
.....
--+-.-, ~ "
....,'
.j..J
~ 80
0)
u
~ ~
aJ ~+-
p..,
....-' ~ ,
~
?-.
u 60
~
Q)
2. .,., ...".. - 'T
Figure u
.,.,
~
~
~
Q 40
0
"ri
.j..,I
C)
<1J
r-I e+
r-I
0
U 20
....
"
~'i
o
:-....... ~..
r.r::-
~'- ~'_~rnr - -- ~~ -~~~
=:!-~'.:=$- '-_r'-'. -=-~~
..... ..::r - t:: ~I
~.-- c ' - ~ -"
7: t: -- - 1-: ----r--~
- --4---~
1-~.~.
I-'~
2
4
6
8
10
12
14
Particle Size, Microns
Size-efficiency Curve for Wet-Impingement Scrubber
-------
100
+.J
>=
(\)
u
'"'
QJ
q..
>,
u
1:1
QJ
'r-!
U
'r-!
lj...;
lj...;
~
80
60
Q
o
-i
+.J
~o
QJ
,....
,....J
"
(5
20
o
'+'-'-
4 8 12 16 20 24 28 32 36 40
Particle Size, Microns
Size-efficiency Curve for Spray Tower
Figure 3.
-------
.1-1
I::
Q)
tJ
$-I
Q)
p.,.
>,
tJ
t::
Q)
orl
U
'04
t:;-J
~
w
c::
o
-,.-I
.1-1
tJ
Q)
..-!
..-!
o
U
100
, "
80
,'ro.
60
'~=--'
. ',--:---(-
,r~~~',
40
20
o
1
2
3
4
5
6
7
Particle Size, Microns
Size-efficiency Curve for Venturi Scrubber (6-in.
throat)
C3.500 cfm gas-)
Figure 4.
- '-=-;-r-;
8
-------
100
~
~
-.
(..J
>::
(l)
.'"
(J 60
'c1 ~
4-<
4-<
~
c::
0
or-'
.I-J 40
...:.~
a;
......
;j
20 -rr'-
..
....... .
o
4
8
12
16
20
24
28
Particle Size, Microns
Size-efficiency Curve for Self-Induced Spray Collector
Figure 5.
--+--
32
36
40
-------
+J
~
Q)
tJ
H
Q)
p...
~
tJ
~
(])
'ri
tJ
'ri
4-!
4-!
W
~
o
...-1
+J
U
(])
.--t
.--t
o
U
100
~F
'! ;
T
-
-
. -- .--.- ..~~,~ .'~~ + +- .. .
---' ;-I~
-c
-t
-- --
80
j .. .-. u 1 ,':0 '--.' ie,
~'. ~!""" . ..~ -' - . - .. - -t-.:": u - ..J- . I
-I;~' o~:_~' ~--:.'- ~- ~~ 7'~ ~~' +'--+ - . -; :;; '- :::~-
'-'- ~ '~= ,'= =~ ..- -, ;~: .~~ - .:; ~.- ,~p 'F - .:- 'r~l>'~X;.;
-' l ,~d.'~., -. .~ C --;.." ~~ .:' _-: h ~~ ~-I~~ ~~~: ::~i~ ..~:= ~o ~'l~ ;~:m~
~ ~:-~"-r-'-!":~! - :'~ ,-:'~ ~:f~ :~:~ :~'ll: ~f ;:~: ~~1. c ;~:::, ~~;;- ='.r:.-;=f~-
t~ .:.~~.~ ; _c'. H' .~~~~; ":~:~4~' ;~~ :;=~.t;=} ::.~~ .~
; on 0 ~ -- - '="--'E: -c= ==;::-:.: - l.-= ;,,,!.. .-; '.. -;:;f: u J,';: h,f-, ;,; . :r:..:... : ~d:'.~
. .- u ' ---t='; .'-:'f:'.; ~u ,; "'.r :g. : - - .eF ==--':00;
. ..; 1'0,: -' 0 _::~ ;::1'=,. .. ~~ .. -cF":':, :::1:: ; .~t= u :;; ::..', ;':)= ; ;-': F' .. S
- :-. '=-+:.;; =r=': -c==t:: : -.. ~~-, =-'1=:-:: -;..:r:-; :'10.: _..cor.:.. :-' -; 10'.. _.~ on-:
; n' ; .. =-= h F= ~£..:':: -. ::'-'E ~--. .:'b. "-1' ::::1;-::o',:¥:: n . : T ~'! 3Ifj
,~~.- = ~~ :'~"'~ ~~f'~- : '1, -, '- ' -~,,; . 21
60
40
20
o
20
60
40
80
100
120
140
Particle Size, Microns
Size-efficiency Curve for High Efficiency (Long Cone)
Figure 6.
+J
~ 100
(])
U
H
(])
p...
~ 80
:>-.
tJ
~
(])
"ri
U
"ri
4-!
4-!
W
~
a
-rl
+J
U
(])
.....1
.--t
0 20
U
o
20
10
30
40
~o
60
70
Particle Size, Microns
Curve for High-efficiency (long
Figure 7.
Size-efficiency
cone) Irrigated Cyclone
-------
100
+.I
r::
(])
()
!-I 80
(])
p..
:>.
()
r::
(])
.,...,
() 60
.,...,
Ij..j
Ij..j
~
r::
0
.,...,
+.I
C,)
(]) 40
.....
.....
0
u
20
>="=. ,- '-1= 1=' ..._- ~.-,-----+- -------I- =-..=~ :.c--::; - ..
- .. =~: - ----"-
f--~===t: .- t----- :-- - . l- ..
g~ -:::::t-,- --i- - - .------- ---
~-.r: =1--- ~- f-- ---=- _. -.
;:=::::-~ - - -,. _u ~- , t--- _..t:- -
~ C-:-=!=-: _. - ~ ...::=t=~_.:..
~ r-- ~
- t::-=~ ~ t----- r--
- - - _.
:::t .-.
, ---
.. =t:
;:- + - -r- ~:-=t-=
- - .. --:::: .- -- =
-- ..-- --- -~~
+-
:1:.- _:.;...-
- =+= -'-;=c-.
- ::E- ~'=:.:
- -~
-
I ~
~-
.
~- --
l:=-
- + - -.
I ==+= ~
-
.. :~r= I--
~~ .~--:::..:...- --
.h---
-
-t---t--~-+- =f
-+- .
7=t-::~
o
40
60
100
140
80
120
20
Particle Size, Microns
Size-efficiency Curve for Medium-Efficiency.High Throughput Cyclone
Figure 8.
-------
(Suitable units marked X)
-- ---- --- ------------ -.---------..---- - --" -- - ----
Types of Gas Cleaning Equipment and their Suitability
(All Numbers as shown in Fig. 3)
Condition
1 2 I 3 4 5 6 7: 8 9 10 11 12 13 14 15 16 17 18
Coarse dusts X X X X X X X X X X X X X X X X X X
Fine dusts - - - X X X X X X X X X X X X X X X
Superfine dusts - - - - - - X X X X X X X X X X X X
h,j
v
Very h.ilYl. 1-e££j1t<:.i~99~) on all dus ts - - - - - - - - - - - - X X X X X X
Gases 'at ib'i!gh 1'JiltlV~ 'humidities - - - - X X X X X - X X X X - X - -
u 2' ! I.'
Gases at ~r~'~I!tF.emperatures X X X X - - - - - X - - - - X - - -
Corrosive gases (no special materials X X X X - - - - - X - - - X X X X X
of construction)
Low maintenance requirement X X X X X X X - - - - - - - - - - -
Small space requirement X X X X X X - X X - - - - - - - - -
i Low capital cost X X X X - X - X - - - - - - - - - -
i Low operating (excluding amortisation) X X X X - i X I X I X I X
cost - - - - - I - I - - -
Insensitivity to changes in gas rate X X X X - ! X X - - - - X X I X - X! - - I
I X I X X I -J
I Flammable dusts and gases X X X X X X X - I X X X I X - -
I
I ! !
I I
! i
-------
Table 5:
Properties of Various Filter Fabrics
I !
Approximate I I
Maximum Operating i ~ Resistance to
Temperature in "( --
Type of Fibre Da=ab i li t\" ! Dry Air, 0c. Acids ' Alkalis Biological Agents I
! !
Cotton High ! 90 i LOI': High Low I
Wool i Low 90 i High i ~oderate Low
Polypropylene High 90 I High High High
Nylon Low 110 Low I High High
OrIon Low 120 High Moderate High
Terylene and Dacron Moderate 130 High High High
Nomex Low 200 Moderate High High
Teflon Very low 230 High High High
Glass (silicone-treated) Very low 270 Moderate Moderate High
KEY:
I Inertial Collector
2 Medium Efficiency, Cyclone
3 Low Resistance Cellular Cyclones
4 High Efficiency Cyclone
5 Impingement Scrubber (Doyle Type)
6 Self Induced Spray Deduster
7 Void Spray Tower
8 Fluidised Bed Scrubber
9 Irrigated Target Scrubber (Peabody Type)
10
11
Electrostatic Precipitator
Irrigated Electrostatic Precipitator
Flooded Disc Scrubber Low-Energy
12
13
Flooded-Disc Scrubber Med. Energy
Venturi-Scrubber Med. Energy
High-Efficiency Electrostatic Precipitator
Venturi Scrubber - High Energy
Shaker - Tupe Fabric Filter
Reverse-Jet Fabric Filter
14
15
16
17
18
-------
(A)
(8)
Particle
Size
Particle
Size Midpoint
% of Total
Dus tin Range
(c)
(F)
=
100
Component I fraction emitted
Component 2 fraction emitted
Combined fraction emitted =
Combined fraction collected
Efficiency
(c)
(E)
( I )
=
= l. 0 -
= 1.0-
K x L = M
I - M
(0)
Component 1
Efficiency
at Midpoint
x
(I) = K
(J) = L
(E)
% Dust
Co 11 ected
(F)
% Dust
Em i tted
(G)
Component 2
Efficiency
a t Mid po i n t
x
(H)
Dust
Collec
J
-------
GASEOUS CONTROL TECHNOLOGY
INTRODUCTION
Of the over 200 x 106 tons of air pollution being emitted in the
United States each year, approximately 7/81s is in the gaseous
form. There are many methods of controlling these emissions
including changing the process, changing the materials used in
the process, as well as providing good equipment maintenance
operations and good housekeeping. The purpose of this discussion
however, is to familiarize you with the devices that are most
frequently used to control gaseous-emissions. The techniques
used are:
1. Absorption
2. Condensation
3. Combustion
4. Adsorption
-------
A.
Introduction
1.
ABSORPTION
Terminology
a.
Gas Absorption is defined as the mechanism whereby
one or more constituents are removed from a gas stream
by dissolving them in a selective liquid solvent.
b.
Absorbate - pollutant
c.
Absorbent - solvent
d.
Equi librium
2.
Physical Parameters Affecting Solubility
a.
Pressure
b.
Temperature
c.
Concentration
3.
Mechanism is explained by the Lewis and Whitman two film theory.
4.
Solvent Selection
-------
B.
Absorption Equipment
1.
Packed Columns
a.
Countercurrent -- most common and most efficient type
of equ i pment.
b.
Concurrent
c.
Cross-flow
d.
Packing
I )
Ceramic
2)
Plastic
2.
Spray Air Cleaners -- simple in design but should be used only
with very soluble gases.
3.
Venturi Scrubbers -- should be used only with very soluble gases
and have very high utility requirements.
4.
Plate Columns -- least frequently used in air pollution absorption
applications; provide for gas-liquid contact on separate trays
or plates.
-------
5. Comparison of scrubber operating costs
Scrubber Total
Liquid Liquid pressure pressure Annu~1
rat. pr...ur. drop drop power
Scrubber type (I-p.m.) (p...I.,.) Pump h.p. (in. water) (In. water) fan h.p. Tot~1 h,p. cost
Cross flow
T ellerette packing 50 5 0.3 0.5 1.5 4.3 4.6 $ 370
Berl saddle packing 60 5 0.4 1.2 2.2 6.3 6.7 540
Raschig ring packing 60 5 0.4 3.8 4.8 13.8 14.2 1140
Counter-current
Tellerette packing 120 5 0.7 0.75 1.75 5.0 5.7 460
Berl saddle packing 140 5 0.8 2.2 3.2 9.1 10.0 810
Raschig ring packing 140 5 0.8 6.7 7.7 22.0 22.8 1840
Wet cyclone 80 60 5.6 3.5 4.5 12.8 18.4 1490
Spray tower 100 80 9.6 2.0 3.0 8.6 18.2 1470
Jet 600 60 42.0 1.0 none 42.0 3380
Venturi 110 20 1.9 15.0 16.0 46.0 47.9 3860
Basis of Conparison:
Air Flow - 10,000 cfm
Highly Soluble Contaminant
Contaminant Concentration - < 1%
References for Comparison:
Contaminant Removal Efficiency
Pump Efficiency - 50%
Fan Efficiency - 55%
Annual Operating Days
Power Cost per KWHR -
- 95%
E. B. Hanf, "A Guide to Scrubber Selection,"
Environmental Science and Technology,
~ (2): 110 - 115, (1970).
- 300
I .5et
Air Pollution Control Equipment,
Technical Bulletin 12-1, The Ceilcote Co.,
Inc. Berea, Ohio, 1968.
-------
A.
Introduction
B.
Theory
c.
Equ i pment
CONDENSAT I ON
th~re are two techniques for effecting condensation:
1.
Increasing the pressure
2.
Extracting Heat
1.
Surface Condenser
2.
Contact Condenser
D.
Appl ications
-------
COMBUSTION
A.
Introduction
1.
Combustion-defined as the combination of a material with
oxygen usually accompanied by heat and light.
2.
The desired products of combustion of any organic material
are C02 and water.
3.
The four parameters controlling the effectiveness of combustion:
a.
Time
b.
Temperature
c.
Turbulence
d.
Oxygen
4.
Flammabi I ity Range
B.
Equipment
1.
Flare
a.
Usually operated within flammable range.
-------
b.
Often requires steam Injection to improve turbulence
and prevent sooty emissions.
c.
Appl ication
2.
Thermal Incinerators
3.
a.
Usually operated outside the flammable rar.ge
« 1/4 the lower explosive limit).
b.
Operated between 10000F and 1700°F with residence
times of between 0.1 and 1.5 seconds.
c.
Application
Catalytic Incinerators
4.
a.
Catalysts
b.
Mechanism
c.
Usua II Y operated outs i de the f I ammab I,.: range with
flameless oxidation at between 6000r and IOOOoF.
d.
App I leat ion
Campa r i son
-------
A.
Introduction
1.
ADSORPTION
Terminology
a.
Adsorption -- fluid-solid process for the removal
of one or more constituents from a gas (fluid)
stream (using either physical or chemical means)
b.
Adsorbent -- sol id
c.
Adsorbate -- pollutant
d.
Activation
2.
How does Adsorption Occur?
a.
Mechanism
b.
Process -- can be either physical or chemical
3.
Adsorbent Materials
a.
Nonpolar -- carbon Is the most common adsorbent
b.
polar
c.
Impregnations
-------
4.
Factors Affecting Adsorption
a.
Pollutant Concentration
b.
Surface Area
c.
Temperature
d.
Molecular Weight of Pollutant
B.
Adsorption Systems and Equipment
1.
Nonregenerative
2.
Destruct
a.
Usually a Thin Bed
b.
Low Efficiency
c.
Used for Low Concentration Application « 2 ppm)
a.
Impregnated Adsorbent
b.
Used for Intermediate Concentration Application
(2 - 1000 ppm)
-------
3.
Regenerative -- Most Common Method of Regeneration Uses Steam
a.
Usually a Thick Bed
b.
High Efficiency
c.
Used for High Concentration Application
(> 1000 ppm)
-------
A.
B.
ODOR MEASUREMENT AND CONTROL
Introduction
1.
Odor Definition - the perception of smell; or that which is
sme 11 ed.
2.
Odor Sources
a.
Confined
b.
Unconfined
Odor Characterization
I.
Intensity
a.
Descriptive Method
b.
Weber-Fechner Law
2.
Quality
a.
Crocker - Henderson
b.
Quality - Intensity Profi le
3.
Acceptabi lity - can be measured on two bases.
a.
Hedonic (like - dislike)
b.
Act ion
-------
4.
Pervasiveness - ability of different quantities of different
odorants to odorize a certain volume of air.
a.
Odor Threshold
b.
Odor Unit - number of odor units in a volume of
an odorant-air mixture is the number of dilutions
(with odor-free air) required to bring that volume
of gas to Its odor threshold.
C.
Odor Control Procedure
1.
Analyze
2.
Control
a.
Gather Evidence
b.
Trace Source
a.
Process Change
b.
Di lution and Dispersion
c.
Adsorption
d.
Oxidation
1)
Combustion
2)
Non-air Oxidation
-------
e. Liquid Scrubbing
1) Absorpt i on
2) Condensation
3) Particulate Removal
f. Odor Neutralization
1) Masking
2) Counteraction
3.
Evaluate Control
-------
~ I'Jstrial odor pollutants today and their c:en7rol - a selection
REFE.f
-------
GROUP PROBLE M
Each group of trainees should evaluate the gaseous emission
problem assigned to the group with respect to the methods of
gaseous control listed below.
Methods of Gaseous Control
A.
Change of Raw Materials
B.
Combustion
1.
Flare type
2.
Furnace type
3.
Catalytic type
C.
Absorption
1.
Packed tower
2.
Spray tower
3.
Venturi scrubber
D.
Adsorption
1.
Regenerative system
2.
Non-regenerative system
E.
Process Change
Each gr.oup should evaluate each method of control listed above
and be prepared to give reason( s) for the feasibility or non-feasibility
of each method. After discussing the feasibility or non-feasibility
for each lYE thod of gaseous control, select the "best" method of control
and prepare a preliminary schematic diagram for a gaseous control
system. .
-------
GROUP PROBLEM I
In the manufacturing of biodegradable soaps. and detergents, dlmethyl-
amine Is used as a raw material. This chemical has a fishy odor at con-
centrations below 100 ppm and down to ~ ppm. It Is slightly water soluble,
combustible and alkaline.
Per I ad i ca II y the d i methy I am i ne concentrat ions re I eased from the
process are wef I within or above the flammable range.
The fol lowing Information is given on dimethyl amine
Molecular weight
801 I ing point (I atm)
Freezing point
Vapor pressure chart
Select a method for control I ing this problem.
,~ r~
45.084
6.88 °c
-92. 19°C
is attached
,', ""'
GROUP PROBLEM 2
The gaseous effluent from a manufacturing process contains benzene
In concentrations of 4000 ppm. A trace of iron, lead and copper is present
In the gas. The flow rate of the gas is 10,000 scfm and the temperature.
is 320°F. i,
I '\
The following information Is given for the problem: J
j (i
(I) Explosive range of benzene in air .
lower 1.1%; upper 4.8% ",f'
(2) Cost of operating combustion device ,,\~,J: i'"
with ~ heat recovered
(3) Heating value for benzene: 3500 BTU/SCF
" ,
, '
i '
'\
Cost In $/Hr. per 1000 scfm
Catalytic Incinerator Fume Incinerator
Credit 0.20 O. 10
O. II 0.10
0.11 0.10
0.03 0.03
0.05 0.33
Fuel
Deprec I at f on
l.1a I ntenance *
Labor and Power
* Assumes compatabl I Ity of gas with the
catalyst
-------
GROUP PROBLEM 3
Hydrocarbon vapors (primarily acrolein) are emitted in the effluent
gases from the batch operation of varnish cookers. The hydrocarbon gases
are insoluble in water but moderately soluble in organic solvents. The
concentration of the hydrocarbon vapors in the varnish cooker effluent
gases is below the flammable range for the gases. Select a method for
hydrocarbon contro'l from varn i sh cookers.
(NOTE:
In the atmosphere, acrolein wi II cause eye Irritation.)
"I,"
'.',li'
GROUP PROBLEM 4
Fluoride compounds are emitted as air pollutants in the manufacturing
of phosphate ferti I izers. Management would I ike to remove si I icon tetra-
fluoride (SiF4) from the effluent gases resulting from the thermal
processing of phosphate rock (a raw material). Si I icon tetrafluoride
is a water soluble, non-combustible gaseous pollutant. Some sol ids
(phosphate rock dust) are present in the effluent gases along with the
SiF4' Select a method for SiF4 removal.
(NOTE:
When SiF4 contacts water, the fol lowing reaction occurs
3 SIF4
+
4 H20
.... 2 H2 S I F 6
+
S i
-------
10)000
8,000
6.000
< 4,000
}:-
iJ
0
:r.J
""0 2,000
::0
('T1
(f)
(f)
C
7J 1,000
('T1 800
z 600
~
~
400
:I:
(j)
200
I 1 '--
-"
: ./
I : I /'
:
! ' ~ , I V
! i i ' ~ t i
I 1 ./
, : I / !
I ! I : / ~
: I , I
I i~ I ! I
I I I I
I
~ I ' I
,
,
I
V I i i ' I
. I I
~ !! I '
. 1 .
,
~ I
"" : - i
~ I I '
./ I 1 I ,
I
I
,
I
i I
VAPOR PRESSURE OF PURE OIMETHYLAMINE I
I I
I
-0
o
;0
so
90
30
40
50
10
20
60
TEMPERATURE IN DEGREES CENTIGRADE
-------
,
Section One
INTRODUCTION TO CONTROL TECHNOLOGY
Classification and Definition of Atmospheric Pollutants
Control of Industrial Emissions .
Control by Raw Material and Process Change
-------
Classification and Definition
of
Atmospheric Pollutants
R.A. Salter, Technical Author
T.A. Hackman, Program Design
INTRODUCTION
To permit discussion of air pollutants,
certain distinctions must be made. The
contaminants must be classified and
various te~ms must be defined.
It is logical to begin with a definition of
air pollution. This is not as easy as it
may sound. Practically every authority on
th~ subject has his own definition, and few
can agree on anyone. We will use the
definition proposed by the U.S. Public Health
Service in its publication, "Guiding
Princip les -- State Ai r Pollution Legislation":
Air pollution may be defined as
the presence in the outdoor atmos-
phere of one or more contaminants or
combinations thereof in such quantities
and of such duration as may be, or
may tend to be injurious to human,
plant or animal life, or property,
or which unreasonably interfere with
the comfortable enjoyment of life,
or propertrj or the conduct of
business. (
It is not to be inferred that the following
classifications are the only possible ones,
nor that all possible pollutants have been
covered. These classifications have been
chosen for the s3ke of convenience in
discussion.
Using the above definition, select the
pollutant from the two given possibilities
and write it in the blank space. Cover the
right side of the page and check only after
you have responded.
Throughout this text, the correct answer
is given in the right-hand column. Please
keep this column covered, write your answer
in the space provided, then check your work.
(1) flys -- pollen (1) (1) pollen
(2) smoke - airplanes (2) (2) smoke
(3) sulfur dioxide -- fog (3) (3) sulfur dioxide
PA.SE.43.6.67
1
-------
CL~SIFICATION ACCORDING TO ORIGIN
This is the first classification that
you will teach yourself. Pollutants
emitted directly to the atmosphere and found
in the form in which they were emitted are
classified as PRIMARY pollutants.
Some examples of primary pollutants are
given in Figure 1 below. They are produced
from the combustion of fuels and are found
in the atmosphere in the same form as
emitted from the source. Many of the com-
monly-encountered pollutants are primary.
SECONDARY pollutants are those not directly
emitted to atmosphere. On the blank line
under PRIMARY in Figure 1 print the title
for the group of pollutants which are not
emitted directly to the atmosphere. Check
answer number (4).
(4) secondary
PRIMARY, e. g.,
sulfur dioxide
nitrogen dioxide
hydrocarbons
I
ORIGIN
S
---------
Figure 1
Secondary pollutants are formed in the
atmosphere by some reaction. A primary
pollutant is emitted directly to the
atmosphere as the result of some process.
A (5) pollutant is
emitted to the atmosphere; a (6)
pollutant is formed in the atmosphere.
(5) Primary
(6) Secondary
Some examples of secondary pollutants are
products of: -photochemical reactions
(reactions catalyzed by sunlight)
-hydrolysis
-oxidation
2
-------
Fill in the blanks with the examples.
PRIMARY, e. g.,
sulfur dioxide
nitrogen dioxide
hydrocarbons
ORIGIN
SECONDARY, e. g. ,
products of
Figure 2
An excellent example of the formation of
secondary pollutants is photochemical smog,
such as occurs in the Los Angeles area.
Through a series of reactions, ozone is formed.
The ozone, in turn enters into reactions
with unsaturated hydrocarbons and other
pollutants ,,,hich are present. The products
of these reactions cause the eye irritation,
crop damage and other effects attributed to
smog.
Ozone is formed in the atmosphere. Ozone is
a (7) pollutant.
~-------- ----
(7) secondary
It should be noted that the same material
can be a primary pollutant in one situation
<1nd in another be secondary.
A bit of iron oxide blown from a stack is
collected in
-------
Secondary pollutants are formed in the
atmosphere by some reaction. A primary
pollutant can react with some other material
in the atmosphere. It may be a natural
component, e.g., oxygen; or it may be another
(12) or secondary
pollutant. This reaction may be photo-
chemical (catalyzed by sunlight), or it can
be a reaction of another type. A pollutant
resulting from such a reaction is classified
as a (13) pollutant.
Ozone, which is a product of a photochemical
reaction, is d rather notorious
(14) pollutant. It is notorious because it
reacts with other pollutants to cause eye
irritation, crop damage and other ill effects.
(12) primary
(13) secondary
(14) secondary
CLASSIFICATION ACCORDING TO STATE OF MATTER
Pollutants may also be classified according
to the state of matter in which they occur,
i.e., they may be gaseous or particulates.
Fill in the blanks:
STATE OF MATTER
--------------(15)
(15 gaseous
-------------------(16)
(16) particulate
Figure 3
While considc'ring GASEOUS atmospheric
pollutants It is helpful to recall the
properties of gases:
- A gas has nci ther independent shape nor
volume.
A gas tends to expand and take the shape
of the vessel that contains it.
Gaseous pollutants behave much as the air
itself; they do not tend to settle out.
Some examples of gaseous pollutants are
sulfur dioxide and nitrogen dioxide.
4
-------
PARTICULATE pollutants include finely
divided solids and liquids. The following
are examples of particulate pollutants:
dust
smoke
fumes
}
solids
mist
fog
spray
}
liquids
Fill in the blanks
I
PRIMARY
I
Sulfur dioxide
nitrogen dioxide
hydrocarbons
ORIGIN
SECONDARY
photochemical products
hydrolysis products
oxidation products
-------------(17) {
STATE OF MATTER
------------------(18) {
Figure 4
sulfur dioxide
(17) Gaseous
nitrogen dioxide
:;ome l'xwnp leg n f solid particulates which
are found J 11 the atmosphere are fly ash,
fibers of various types and pollens. A
frequently encountered liquid pollutant is
112S04 mist.
rSOlidS
(18) particulate
LliqUidS
The larger particulates settle out quickly.
They produce their effects near the source.
Moderate size particles travel further, and
eventually settle out some distances from
the source; this is dependent upon size,
rate of emission and meteorological factors.
The smallest particulates (less than about
l~ in diameter) behave almost like a gas.
They remain suspended almost indefinitely, and
are readily transported by wind currents.
5
-------
Gaseous pollutants behaye much as the air
itself; they do not tend to settle out.
Sulfur dioxide is a gas. Would it be likely
to settle out? (Yes or No .(19)
Particulate pollutants include .not only
solid, but also liquid materials. A mist
is a suspension of liquid droplets. Sul-
furic acid mist may be classified as a
(20) pollutant. Particulates of
greater than 1~ diameter will eventually
settle out. Smaller particles behave
almost like a gas. They (remain, do not
remain) (21) suspended.,
(19) No
(20)
particulate
(21)
remain
Before we go on to the classification
according to chemical composition, let's
a quick review. Fill in this schematic
diagram of the classification.
have
I. ---------
II. ---------
--- -------
I
III.
9.!FJ1:!;£~ !;;Q~O.?!nOJi
Figure 5
If you cannot recall the classifications,
turn back and review the diagram in Figure
4, page 5.
CLASSIFICATION ACCORDING TO CHEMICAL
COMPOSITION
The first distinction in the classification
according to chemical composition is be-
tween organic and inorganic compounds.
ORGANIC COMPOUNDS MAY BE DEFINED AS THOSE
WHICH CONTAIN CARBON AND HYDROGEN AND MAY
CONTAIN OTHER ELEMENTS.
Would this definition exclude carbon
monoxide (CO), carbon dioxide (CO2) and
carbonates (CO;) as organic compounds?
Yes or No (22) Why? (23)
(22) Yes
(23) Contain carbon,
but no hydrogen
6
-------
If you answered "yes" you were correct.
These simple carbon compounds do not contain
hydrogen.
"AlLhough several hundred thousand
organic compounds are known, these
fall into a reasonably small number
of groups, the members of which
exhibit many common characteristics.
This natural classification makes
possible a comprehensive understanding
....from a consideration of properties,
reactions and methods of preparation
of typical series." (2)
Let liS cow; ider some of these classes.
do so moc:r qui('kly, the figure below is
givl.'n.
To
ORGANIC
I
(
J
)
HYDROCARBONS
aliphatic
aromatic
alkanes
alkenes
alkynes
Have you studied the figure diligently?
HYDROCARBONS are those compounds which
contain only carbon (C) and hydrogen (H).
'~e two major classifications under hydro-
carbons are (24) and
----- ---
(25) .
ALIPHATIC 'is a term which chemists place
before hydrocarbon to designate a class
of chemical compounds by indicating
"structural concepts." Substances be-
longing to this group (aliphatics) are
sometimes referred to as open-chain com-
pounds. (3) Tile figure below may be very
helpful.
Figure 6
(24) aliphatic
(25) aromatic
Aliphatic
STRUCTURAL FORMULAS
H H H H H
I I I I I
H - C - C - C - C - C -
I I I I I
H H H H H
H
I
C - H
I
H
Figure 7
7
-------
Three more headings follow under the
aliphatic classification. The first,
ALKANES, are the saturated hydrocarbons,
i.e., the carbon valences are all
saturated with hydrogen.
The members of the alkane group may be
consider~u as an HOMOLOGOUS SERIES, i.e.,
a group having similar physical and
chemical properties. Each member differs
from the preceding one by one carbon and
two hydrogen atoms, e.g., CH4' C2H6
C,I11\.
1'1 LL 1 N '1'111< 1\ LANKS
Primary
1.
ORI(~IN
Secondary
Gaseous
II .
STATE OF MATTER
Particulate
Ifl.
( 26)
CHEMICAL
COMPOSITION
Inorganic
Hydrocarbons
others
(27)
(28)
a1kenes
a1kynes
8
Figure 8
aromatic
(26) organic
(27) aliphatic
(28) alkane
(29) saturate
-------
The first member of the alkanes
(5 - - _(Z9) hydrocarbons) is
medlane -:-
Methane is the simplest possible hydrocarbon,
and may be considered as a parent substance
from which all other aliphatic hydrocarbons
are derived.
H
METHANE I CH4
H-C-H
I
H
H H
I I
ETHANE H-,-f-H CZH6
H H
f H H
I I
PROPANE H-M-f-H C3Ha
H H H
H H H H
I I I I
BUTANE H-C-C- C- C-H C4HlO
I I I I
H H H H
H H H H H (Fill in Formula)
H-~-~- L t-~-H C H (30)
PENTANE
I I I I
H H H H H
Figure 9
From pentane on,
using a .prefix to
carbons, plus the
six carbons.
the compounds are named
indicate the number of
ending -ane, e.g., hexane,
The prefix "dec-" indicates "ten". How
would you name an alkane which contains ten
carbons?
(31)
(31) decane
9
-------
Members of an homologous series are usually
closely related in both physical and
chemical properties. The alkanes, are
characteristically inert, i.e., they do not
tend to react very readily.
Let us have a short review of the aliphatic
hydrocarbons we have just considered.
As the name implies, hydrocarbons contain
on1y_____-- and ---------____.(32)
(32) carbon & hydrogen
An aliphatic hydrocarbon is one in which
the carbon atoms are arranged in an open,
chain-like arrangement. According to this,
a compound having the formula:
\' 'I II r I I
11- f- r ,-,- 1-1- f-H
H H H H H H H
is
an --------(33) hydrocarbon.
(33) aliphatic
A saturated hydrocarbon is called an alkane.
In ethane, all the carbon valences are
saturated with hydrogen. Ethane is an
. (34)
(34) alkane
Alkanes are characteristically inert. A
certain hydrocarbon will not react with
any of the ordinary reagents (acids, bases,
etc.). Would you expect this hydrocarbon
to be an alkane? (Yes or No)
(35)
---- -------
(35) yes
The next 3erie8 to be considered is the
a1kenes. often called olefins. This series
of hydrocarbons is unsaturated. This
means that the compound contains one or
more double bonds, i.e., there are two
pairs of shared electrons between carbon
atoms. Let us explain this further.
Alkanes contain single bonds between
carbon atoms. This may be represented
as follows:
Ie: c
The two dots represent the electron pair
that is shared by the two carbon atoms.
The structure may be indicated more simply:
I c
c I
This is the way it is most often found in
the 11 terature.
10
-------
We have said
bond. There
tween carbon
presented as
that alkenes contain a double
are two electron pairs be-
atoms. This may be re-
j C : : C or C = C I
The second structure, C = C, is the one
most often used.
Alkenes are also (36),
not aromatic, hydrocarbons:--fhis-group is
similar to the alkanes in physical
properties, but differs greatly in chemical
properties. Due to the presence of the
double bond the alkenes are highly reactive.
Alkanes, we said, are characteristically
----------, (37) or simply inactive. The
alkencs are (more/less) (38)
reactive than the alkanes.
(36) aliphatic
(37) inert
(38) more
The lowest member of the alkene series is
H H
I I
ethene, HC=== CH (common name, ethylene).
There is no alkene which corresponds to
methane. There must be at least two carbon
atoms for the double bond to be present.
The nomenclature is similar to that of the
alkanes, substituting the ending -ene. If
pentane is an alkane which contains five
carbon atoms, what would you call an
alkene containing five carbon atoms?
(39)
-------------
(39) pentene
Because of their reactivity, alkenes are
much more important in the study of air
pollution than are the alkanes. This is
hecause they enter into the formation of
secondary pollutants.
ALKYNES. These hydrocarbons are a160 un-
saturated, containing triple bonds between
carbon atoms.
[ C : : : C or C::::;;;:C
The simplest member of this homologous
series is ethyne (or acetylene), HC8iimCH.
The compounds are named in the same manner
as the alkanes and alkenes, with the
substitution of the suffix -yne. The alkyne
which corresponds to butane and butene would
be (40).
(40) butyne
11
-------
The other hydrocarbon group to be con-
sidered is the AROMATIC group. The key
compound to remember in this group is
benzene. All the other aromatics are
derived from or related to benzene. The
structural formula for benzene is shown in
Figure 10.
H
I
/Cl
HI . H
1 /H
""c~
J
Figure 10
The six-carbon unit shown here is the
identifying note of the aromatics. It is
commonly referred to as the benzene ring.
The six-carbon unit remains throughout
ordinary chemical transformations and
degradations. Aromatics do not display the
reactivity so characteristic of unsaturated
aliphatic hydrocarbons.
We have said that aromatics, as a rule,
are relatively non-reactive. Would you
expect an aromatic hydrocarbon (benzene,
for example) to be of importance in the
formation of secondary pollutnnts? Yes or
No (41) Why?
(41) No. Does not
readily enter
into reactions.
TIle six carbon unit remains throughout
ordinary chemical reactions. The identify-
ing note of the aromatics is the
ring (42).
--------
(42) benzene
One group of aromatic hydrocarbons which
should be mentioned is the group known as
POLYNUCLEAR hydrocarbons. These are the
aromatic hydrocarbons which contain two
or more ring systems. Those aromatic
hydrocarbons which contain more than one
ring system are called (43)
hydrocarbons
(43) polynuclear
12
-------
Some examples of polynuclear hydrocarbons
are naphthalene, fluorene and pyrene
Figure 11 shows the structure of these
compounds.
CD
(g)
NAPHTHALENE
FLUORENE
PYRENE
Figure 11
A number of these polynuclear hydrocarbons
have been shown to be carcinogenic, and are
therefore very important atmospheric
pollutants. Polynuclear hydrocarbons are
of interest because some of them have been
shown to cause cancer, i.e., they are
(44) .
(44)
carcinogenic
The following figure should serve as a
short review of organic pollutants we have
already considered, viz., the hydrocarbons.
i
(
alkanes
aliphatic
alkenes
hydrocarbons
I
alkynes
ORGANIC
(
I
aromatic
aldehydes & ketones
Figure 12
Now we will proceed to the next group, the
aldehydes and ketones.
-------
ALDEHYDES AND KETONES. Aldehydes and
ketones contain carbon, hydrogen and
oxygen. Thus aldehydes and ketones differ
from hydrocarbons because they contain
. (45)
-----------
To simplify the study of aldehydes and
ketones, let us first see what they look like.
These are the general formulas: .
Aldehyde
R - C =0
Ketone
R - C =0
I
R
Figure 13
In these formulas the R represents an ALKYL
(hydrocarbon) group. Let us illustrate
this by examples.
Hydrocarbon Alkyl group
methane, CH4 methyl, CH3
-
butane, C4HIO butyl, C4Rg
octyl, CSHI7 -
octane, CSHIB
In each case the alkyl group contains ~
less hydrogen atom than the corresponding
~~ocarhon. If the formula for pentane is
C511l2' what is the formula for the pentyl
group? (46)
- - -~-------
l11C a1ky] grol1p which corresponds to
propane 18 -------____.(47)
In Figure 11 circle the part of the formula
which is the same for aldehydes and ketones.
(4S)
In aldehydes and ketones. the FUNCTIONAL
GROUP. (the group responsible for the
activity of the compound) is the - C==O
group; it is called the CARBONYL group. It
is the distinguishing characteristic of the
aldehydes and ketones. Because of this
carbonyl group, aldehydes and ketones are
among the most reactive of organic compounds.
14
(45) oxygen
(46) C5Hll
(47) propyl
(4S) -C=O
-------
Suppose you are given two compounds with the
following structural formulas:
Com!-'ound A
CH3-C=0
I
H
Compound B
H
I
CH-C-H
3 I
H
Figure 14
Which compound would you expect to be more
reactive? A or B (49). Why?
(49) A. It contains
the carbonyl
group
Which would probably present more of a
problem to an air pollution control official
-- A or B? (50) Why?
(50) A. Would
tend to react
to form
secondary
pollutants
CARBOXYLfC ACIDS. This is a third group
of organic compounds. Once again, let us
have a schematic view of the classification.
Inis time you should do it. It won't take
a minute if you have been attentive up
to this point.
1.
ORIGIN
{
II.
STATE OF MATTER
{
, I
) )
ORGANIC
INORGANIC
I
others
Figure 15
15
lIT.
CHEMICAL
COMPOSITION
-------
You may check your answers from Figure 8 on
page 8 .
The carboxylic acids are also oxygenated.
In this group of organic acids, the
functional group (the group responsible
for the activity of the substance) is
called the carboxyl group. The carboxyl
group may be indicated by the formula
-c=o.
I
OH
In the general formula for carboxylic acids
indicated below, circle the functional
group. (51) It is called the
group (52).
R - C =0
I
OH
GENERAL
FORMULA
Figure 16
Most carboxylic acids are weak acids. The
R substitutes (alkyl groups) have little
effect on their strength.
This concludes the discussion of the
organic pollutants. These are the ones we
consider most important to the study of air
pollution. However, a list is included
under the. heading "others". These are
pollutants which are of lesser importance
and could not be given more space, because
of the scope of this program.
ORGAN J CS
HYDROCARBONS
ALDEHYDES AND KETONES
CARBOXYLIC ACIDS
OTHERS
alcohols
ethers
esters
amines
organic
sulfur compounds
Figure 17
16
(51) -C
o
OH
(52) carboxyl
-------
Now let us have a short review of organic
pollutants.
Organic compounds are those which contain
carbon and hydrogen, and may contain
other elements. Hydrocarbons contain only
carbon and hydrogen. A certain compound
has the formula C~H12 It is a
(53). The saturatea nydrocarbons are
called alkanes; the unsaturated hy-
drocarbons include two groups -- a1kenes
and alkynes. A1kenes are (saturated,
unsaturated) (54) hydro-
carbons. The ending -ene indicates
alkenes, -yne indicates a1kynes. Name the
alkene which corresponds to ethane. (55)
Name the alkyne which corresponds to ethane.
(56) All the aromatic hydrocarbons are
related to or derived from benzene. The
identifying note of the aromatics is the
(57) ring.
------~---
Roth aldehydes and ketones contain the
carbonyl group, - C:=O. The distinquishing
characteristic of the aldehydes and ketones
is the (58) group. Carboxylic
acids tak~their name from their functional
group. The functional group of the
carboxylic acids is called the
(59)
group.
LET US QUICKLY REVIEW AGAIN THE
SCHEMATlC DIAGRAM OF THE CLASSIFICATION
(53) hydrocarbon
(54) unsaturated
(55) ethene
(56) ethyne, more
commonly re-
ferred to as
acetylene
(57) benzene
(58)
carbonyl
I. ORIGIN {
] 1. STATE OF MATTER \
I
I ORGANIC
III. CHEMICAL
COMPOSITION
j
(59)
carboxyl
I
aliphatic
-~~ --
I
Figure 18
~--
others
17
-------
You may check your answers from the class-
ification you have already completed in
Figure 15 on page 15. If you have writ-
ten the wrong answers in Figure 18, be sure
to correct them before you continue.
lNORGANIC POLLUTANTS
The other group of pollutants to be con-
sidered are the INORGANICS. Inorganic
materials found in contaminated atmospheres
include the simple carbon compounds (carbon
monoxide, carbon dioxide and carbonates)
and non-carbon-containing compounds. Carbon
monoxide is a (organic, inorganic) -
(60) pollutant,
(60)
inorganic
Many of the most commonly encountered
pollutants are inorganic. This large
of substances may be considered under
rather broad headings.
group
a few
Sulfur Compounds
First let us consider those pollutants which
contain sulfur. This group includes sulfur
dioxide, sulfur trioxide, sulfuric acid and
hydrogen sulfide. Combustion of sulfur-con-
taining fuels is largely responsible for the
presence of these contaminants.
In sampling for various pollutants you detect
large quantities of sulfur dioxide in the
air. Only two possible sources are nearby --
the power plant or the cement plant?
(61)
(61)
power plant
There is evidence that these sulfur compounds
(S02 especially) tend to react with other sub-
stances in the atmosphere. These sulfur
compounds react to form S
---------------
pollutants. (62)
Sulfur dioxide, sulfur trioxide, sulfuric
acid and hydrogen sulfide are all
(63) containing compounds. Most are emitted
from the combustion of (64)
-containing fuels.
(62) secondary
(63) sulfur
(64) sulfur
Carbon oxides
-- ---
Carbon dioxide and carbon monoxide are
products of combustion of carbonaceous
fuels. Although carbon dioxide is emitted
from combustion sources, it is not generally
considered an atmospheric pollutant. It
normally occurs in the atmosphere at very high
conc.entrations, and even an increase of a
few hundred ppm is relatively insignificant.
Even at these elevated levels it has not
18
-------
been shown to have any serious and well-
defined adverse effects. Carbon dioxide
(is, is not) (65) a pollutant.
Carbon monoxide is found in the atmosphere
primarily as a result of motor vehicle
exhaust. Relatively high concentrations
have been encountered, but levels toxic to
man have not been found in the ambient
atmosphere. The major source of carbon
monoxide is (66).
Nitrogen compounds
This group includes oxides of nitrogen and
ammonia. Chides of nitrogen and ammonia are
------- (67) -containing compounds.
Nitric oxide and nitrogen dioxide are pro-
duced by combustion of organic matter. The
major source of nitric oxide and nitrogen
dioxide is the combustion of (68)
matter. The major interest of both nitric
oxide and nitrogen dioxide is related to
their participation in atmospheric photo-
chemical reactions. These nitrogen oxides
enter ~nto the formation of (69)
pollutants.
Ammonia is emitted from combustion sources
and from chemical industries. It is of more
localized interest than are the oxides of
nitrogen. In an area with no chemical
industry, hut numerous other industries, which
would b(, more likely to be found in the air
-- nitrogen dioxide or ammonia?
(0)
Oxidants
- ------
Ozone and other oxidizing substances found
in the atmosphere may be considered under
the heading of total oxidants. Total
oxidants may be taken to mean
(71) plus other oxidizing substances.
The real importance of oxidants is their
participation in the atmospheric photochemical
reactions. Oxidants themselves are often the
product of such atmospheric reactions.
Oxidants may themselves be (72)
pollutants, or may react to form other
(73) pollutants.
Oxidants are not necessarily inorganic
substances. Many of the oxidizing
materials found in the atmosphere are
organics. We have considered them to-
gether here as a group because of their
similar properties.
(65) is not
(66) motor vehicle
exhaust
(67) nitrogen
(68)
organic
(69)
secondary
(0)
nitrogen
dioxide
(71)
ozone
(72)
secondary
(73)
secondary
1~
-------
Halogen compounds
This group includes hydrogen fluoride,
hydrogen chloride and metallic fluorides.
HF and HCl are corrosive and irritating.
Metallic fluorides cause fluorosis, a
fatal disease in cattle. HF, HCl and
metallic fluorides are (74)
compounds.
Various other pollutants of relative
importance could be considered - organic
sulfur compounds, other nitrogen compounds,
etc., - but the need for brevity prevents
more than mere mention of them.
(74) halogen
1.
{
ORIGIN
11.
ST ATE OF MATTER
{
(
III.
CHEMICAL
COMPOSITION
I
( hydrocarbons {
aldehydes & ketones
carboxylic acids
( others
{alkanes
a1kenes
alkynes
Check your answers with Figure 15 on page
18, aud correct any wrong answers.
SUMMARY
Pollutants may be classified according to
several schemes. For convenience in dis-
cussion, we have classified them according
to origin ( ) and ( )(75),
according to state of matter ( ) and
( ) (76), and according to chemtcal
composi tio; ( ) and ( ) (77) .
20
sulfur compounds
carbon oxides
j nitrogen compounds
oxidants
halogen compounds
Figure 19
(75) primary
& secondary
(76) gaseous &
particulates
(77) organic &
inorganic
-------
REFERENCES
1.
Tetzlaff, F., et a1. "Guiding Principles
- State Air Pollution Legislation."
U.S. Department of Health, Education
and Welfare, Public Health Service,
Division of Air Pollution. Washington
25, D.C. May 1, 1962.
2.
Fieser & Fieser. Organic
Reinhold Publishing
Corporation. New York.
Chemistry .
1956. p. 21.
3.
Arthur C. Stern, ed. Air Pollution.
Vol. I, Academic Press.
N.Y. 1962.
COMMENTS
(Constructive criticism cheerfully accepted)
-------
CONTROL OF INDUSTRIAL EMISSIONS
FUNDAMENTAL APPROACHES TO
CONTROL
e
More efficient operation of existing
equipment
A
Regardless of the air pollution problem
to be attacked.. that is, whether it be a
community-wide problem or merely a
single- sou~ce problem. . . there are two
fundamental approaches to control:
2
For industries developing entirely new
products or processes, it is important
to think about pollution problems in the
research laboratory. With such an
approach:
Control of the pollutant at the source
so that A'. :-::"'Jive amounts are not
emitted to the atmosphere in the first
pla,'('.
a It may be found that, when looked
upon from an air pollution angle,
other lines of research differing
from those being followed, may
prove more promising.
2
Natur'al dilution of the pollutant aIter
it has been emitted to the atmosphere
to such a concentration that man,
ammals, vegetation, and materials
will not be harmed.
b Or, by developing a more expensive
process, but onp whicb reduees or
eliminates the J1{'ed for air pollution
control equipment, it may be found
that the over-all production costs
will be cheaper.
II
CONTROL OF THE POLLUTANT AT
THE SOURCE
c
If the pollutant cannot be prevented
from forming, and its uncontrolled
mass rate of emission to the atmos-
phere is excessive, equipment which
destroys, alters, or traps the pol-
lutant will be required
A
Control of the pollutant at the source
may be acc2..,mplished by:
Keeping the pollutant from coming
into existpnce
2
If it comes into existence, destroy,
alter, or trap it before it can get out
into the at.mosphere
3
There are several basic methods of
reducing a pollutant to tolerable levels
of concentration before it is emitted
from the stack top:
B
The most positive way to abate air pollu-
tion jS to ke('p the pollutant from coming
into existen('e; or, if this is impossible,
to k'(;~pth(' qtl'3ntity that does form to a
bar<' 111lnlt11Um,
a
Destroy the pollutant
Mask the pollutant
b
('
Count~rad the pollutant
Colled tht' pollutant
For' lIldustt'ies already in operation,
tll1s 1l1~1\' 1,(, done by:
d
4
Destroying thp pollutant
(1
Ibw material changes
0pt'ratlOnal changes
a In destroying the pollutant, two
gene ral methods are used:
b
('
1\!Jdifi"ation or replacement of
I)I'O,'(''-;S equipment
1) Usp of fire
d
Adopting an altC'rnate method to
pt'odu('p the samp product with
1'('\\'('1' <1tmospherit- wastes
2) Usp of ,'atalyti,' burnprs
1'.\. C. ~. ,-J. (;(1
-------
CONTROL BY RAW MATERIAL AND PROCESS CHANGE
C. A. Lindstrom*
I
BASIC APPROACHES FOR THE MINIMIZATION OF
POLLUTANT GENERATION
A primary method of controlling air pollution
is to keep the pollutants from forming, or,
at least, to keep the pollutants that do form
a t a mini IlIUIJI. The re are four basic approaches
for the minimization of generation of pollut-
ants:
A
l'se 1'[ raw materials and fuels of low air
1'01 JlIt i on potential.
B
Pruper design of process and burning
equipment involved in handling, processing,
and Durning materials.
C
Pruper uperation and maintenance of equip-
ment involved in handling, processing, and
burning materials.
D
Control of process and burning activity.
II
RAW ~1i\TC:RIALS AND FUELS
Use uf raw materials and fuels from which no
air pollutants will be directly, or indirectly
formed would be ideal. Where this is an im-
practical attainment, those materials and
fuels which yield minimum pollution should be
used.
For cx"mp lc, the use of low-volatile coal
i.nstl'dJ of l1igh-volatile coal would reduce
SlJIoke substantially; use of low-sulfur fuels
wOlild n.dul"C' oxides of sulfur emission. Sub-
stitute [lIcls for the automobiles, such as,
liquified petroleum gas, alcohol, alcohol-
gasolioe hlends, and low olefinic gasoline,
may reduce the quantity of hydrocarbons emit-
ted to the atmosphere. Additives to present
gasoUne may improve combustion and thus lessen
the pollution potential of the gasoline engine.
In open hearth practice, use of bauxite in-
stead of fluorspar reduces fluoride emission.
For generation of heat for personal comfort
and convenience, use of gas or electricity,
instead of coal and oil, would aid in reducing
smoke, oxides of sulfur, oxides of nitrogen,
and hydrocarbons.
III
EQUIPMENT DESIGN
Process and burning equipment should be de-
signed for optimum production efficiency as
well as for minimum generation of air pollut-
ants whenever it is practical to do so. When
*Presently Regional Program
Charlottesvi 11e, Virginia
p1\.C.8.
-------
I\n addi l lunill operational step may provide
rt'd\lcti"n in generation or escape of pollut-
ants. I,'or eX:lmple, in brass foundry practice
a fluxing material applied to the surface of
molten brass is used solely to serve a8 an
evaporation barrier and reduce emission of
brass (urnes. Perhaps an operational step can
he dis('()nlinlled, such as the manufacture of
an j nt('rm"d i,,(c' raw material that creates an
air poilillion problem, when the same raw
material ~an h" purchased from an outside
~upplicr. A nolurious air polluting operation
migllt h," dbic, to be substituted by another
uperation \vhich provides the same product, or
accomplishment. For example, domestic incin-
eration carried on by the individual may be
substituted by municipally operated domestic
wastes pickup and disposal; or an inefficient
municipally operated incinerator may be re-
placed by a properly operated sanitary land-
fill. A change in operational procedure may
he helpful; for exa~ple, changing the traffic
pattern of automotive vehicles may alleviate
air pollution problems in certain areas or at
certain periods of the day.
v
CONTROL OF ACTIVITY (Meteorological Control)
Rate of generation of pollutant may be con-
trolled by regulating the rate of handling,
pru"essing, or burning of materials. Thus,
I,\, controlling the activity of an air pollutant
producing operation according to the prevail-
ing dispc'rsive ability of the atmosphere, the
rate of "mission of pollutant may be regulated
,.,0 that air quality standards may be maintain-
ed. In other words, during unfavorable meteor-
ologicdJ conditions operational activity may
he reduced resulting in a lesser discharge of
pullutants; L.nder extremely unfavorable
m"teor"logLcal conditions operational activity
may be stopped entirely.
Such method of control of emissions is termed
"meteorological control," and means stopping
or slowing docm operations during meteorological
conditions which are estimated as unfavorable
to dispersion of pollutants. To be successful,
IIIL,teorologic,lI control dewands that the opera-
tion be
-------
b
Meteorological control cannot be
applied to operations where shut-
downs cause loss in production time
and resulting loss in workers'
earnings.
"
Meteorological control is not eco-
nomical usually. The cost of pro-
duction rises.
d
A routine program for predicting
meteorological conditions and
ground level pollutant concentra-
tions is expensive.
('
There may be difficulty in starting,
regulating, and stopping equipment.
f
Success depends upon plant location.
For a given location, favorable
meteorological conditions might not
be sufficiently frequent.
g
Changes in physical environment,
such as development of a community,
may create unforseen problems.
Meteorological control of emission
of pollutants has been applied suc-
cessfully to such operations as
the production of zinc and lead by
the Consolidated Mining and Smelting
Company, Trail, B.C., and the pro-
duction of power by the Tennessee
Valley Authority. However, in most
instances the application of efflu-
ent cleaning equipment, high stacks,
and careful site selection is more
satisfactory.
3
-------
Section Two
OVERVIEW OF PARTICLE REMOVAL
Introduction: The Collection of Particles from a Gas Stream
Introduction: Collection Equipment
Dust Collection Equipment
-------
INTRODUCTION: THE COLLECTION OF PARTICLES
FROM A GAS STREAM
PHASES INVOLVED IN THE COLLECTION
01<' 1'A RTICLES FROM A GAS STREAM
1'1 'I'll<' f~'dion of particles from a gas
slr'('am involves three distinct phases:
I kp()S~tiY-22 on a collecting surface
')
Hl'l~nlion on the collecting surface
:;
!{emoval from the collecting surface
II
DEPOSITION OF A PARTICLE ON A
COLLECTING SURFACE
A To enable deposition of a particle on a
collecting surface, there is need for:
A resultant force upon the particle in
the direction of the collecting surface,
2
A collecting surface upon which the
particle is deposited, and
')
,)
Suffil'ient time for the particle to reach
the collecting surface before the particle
rca(hes the outlet of the collecting
dl"J it,(,.
J{ Tlwt'l, ~r<' six mechanisms by which a
r<~;;uHant force may be created upon a
parlie]p to cause it to migrate toward
a collecting surface, or cause it to be
dirl'ctly intercepted.
Gravity settling
2
Flow line interception
:3
Inertial deposition
PA. C. pm. 1 Ba. 9. 60
4 Diffusional deposition
5
6
E lcctrosta tic precipi ta tion
Thprmal precipitation
III
RETENTION OF A PARTICLP: ON A
COLLECT1NG SURFACE
A The fact that particles are "deposited"
on a surface is no assurance that they
are "collected".
1
To be "collected", they must remain
on the collecting surface until
intentionally removed.
B The problem of retaining a deposit on a
surface is basically one of having suffi-
ciently high surface forces to counteract
the dislodging tendencies of the fluid
shear of the carrier gas stream as the
gas passes over the deposit.
IV REMOVAL OF A PARTICLE FROM A
COLLECTING SURFACE
A For any collection equipment, some means
must be provided for removing the accu-
mulaled deposit, either periodically or
continuously.
B Removal of deposited material assumes
outstanding importance in some instances
1
Although deposit removal is usually
purely a problem of mechanical design,
it must be considered in terms of
overall collection efficiency.
-------
INTRODUCTION: COLLECTION EQUIPMENT
TWO BROAD CATEGORIES OF
COLLECTION EQUIPMENT
3 Self-induced spray deduster
(orifice type)
A Collection equipment may be divided into
two broad categories:
4 Disintegrator
Dry collectors
5 Wet Dynamic precipitator
6 Venturi scrubber
2 Wet collectors
II
DRY COLLECTORS
IV FACTORS IN THE SELECTION AND
DESIGN OF COLLECTION EQUIPMENT
A The dry collectors fall into the following
classifications: .
A Carrier Gas Properties
1
Temperature
Settling chambers
2 Pressure
2
Centrifugal separators
3 Humidity
a Dynamic precipitators
4 Density
b Cyclone
5 Viscosity
1) Simple cyclone (large diameter)
2) High efficiency (long cone)
3) Multicyclone
6 Dewpoint for condensable components
7 Electrical conductivity
3 InC'rtial separators
8 Corrosiveness
a Baffle chamber
9 Toxicity
b Impingement type
10 Flammability
c
Louver type
4
Fabric collectors
B Particulate Properties
5
E lectrosta tic precipitators
Particle size and SIze distribution
2
Particle shape
III WET COLLECTORS
3
Particle density (absolu tl' and bulk)
A The wet collectors fall into the following
c la s s ifiea tions
4 Stickiness, build up tendencies, and
flowability
Gravity spray tower
5 Hygroscopic properties
2 Wet impingement scrubber
PA. C. pm. 19.9.59
-------
Introduction: Collection Equipment
(;
1\ gglomeration tendencies and floc
:-;tability (dispersibility)
7
Electrical conductivity
8
Corrosiveness
~)
Flammability
10
Toxicity
1 ]
ALJrasiveness
12
Flowability
C Conditioning
1
The actual deposition efficiency of a
collector may be modified by condition-
ing the carrier gas stream, the partic-
ulates, or the collecting surface.
2
Conditioning of the particle
a
Condensation on the particle surface
b
Flocculation of the particles
1) Natural
2) Mechanical
3) Electrical
4) Sonic
c
Deposition of solids on liquid
droplets
d
Treatment of the particle surface
e
Electrical charging of the particle
f
g
')
oJ
Conditioning of the carrier gas stream
a
Heating, cooling
[I
lIumidification
('
d
2
4
Conditioning of thf' c011ecting Hurf8Ct'
a Viscous substances
b Irrigation
c
Electrostatic
d Heating, cooling
e
f
D Manufacturing Process Factor s
1
Volumetric gas rate collector must
handle
a
(Retention time required in the
collector)
b
(Velocity through the collectur)
2
Particle concentration collector must
handle
3
Permissible pressure drop across
the collector
E Collector Operation Considerations
1
Maintenance
2
Continuity of operation. (Must it be
shut down and started up'? Must it
take varying loads? etc.)
3
Safety and health protection
a
Toxic hazard
b Explosion and flammability hazard
4
Type of labor required and availability
of such labor
5
Disposal of the collected material
a Waste disposal
b
Product recovery
-------
------~--
Introduction:
Collection Equipment
F Construction and Installation Factors
Floorspace requirements
Sludge tanks, treatment tanks,
agitators, etc.
2
Headroom requirements
Valves, dampers, automatic valves,
regulators
3
A vailability of utilities
5
Materials of construction
a
Water
a
Weather protection requirements
b
Steam
b
Insulation or jacketing requiremc'nts
"
Compressed air
c
Pressure requirements
d
Electricity (A. C., D. C., high
voltage)
d
Temperature limitations
e
Corrosion resistance
4
Auxiliary equipment
f
Erosion resistance
a
Fans, blowers, compressors
b
Pumps
('
Motors and drives
d
Shaking and rapping devices
REFERENCES
e
Conveyors, air lacks, rakes,
storage bins, etc.
Lapple, C. A. "Dust and Mist Collection, "
Air Pollution Abatement Manual,
Manufacturing Chemists Association,
Inc. 1951.
f
Cleanout ports, access doors,
explosion doors, etc.
g
Electrical substation or transformer
2
Perry, J. H. Chemical Engineers'
Handbook, McGraw-Hill Book Co.
Inc. N. Y. 1950.
h
Timer, alarms, etc.,
3
-------
a ,.",hI' Iro-
CbeD1ical
E:ng!!!~~~!~g
, ,
Dust Collection Equipment.
-------
. , . .
. . ':"'.~>,,- ';.(:.;". '. '. . . .:!:. ~"':':"
Chemit:al " t:t:
Engi~~,~ringt~'
i;k, ,.",'. ,'At
,n,r',. '
,l
~_:
j.
, ,
(.. 1.:,' .'
.". .
PHOTOMICROGRAPHS of various dusts
Dust Collection Equipment
GORDON D. SARGENT, Nopea Chemical Div., Diamond Shamrock Chemical Co.
In ~olving .1 dust collection problem, an engineer
mmt /ir~t evaluate his own situation in order to select
the most promising types of collectors. This article
puts together the available facts and sources that the
engineer Iweds for hack ground information. After
making .. preliminary equipment selection, suitable
vendors can he ('ontacted for help in developing the
final answl'r. All ('arly and complete deRnition of the
prohl('m ('an f('duce the false starts that lead to
wasted pilot Irials or costly, inadequate installations.
Sd('ding a dll\t collector for cleaning a process gas
~tn~:1I1I ('all hI' a challenge. Some engineers may try
10 /ind shorlcllh, ;uJ(1 quick estimates put on both
gas now and coiled ion efficiency may be the on tire
('Kll'nt ..r the ('ollector speciRcation. The result can
III' all ill..rr('div(' imtallation that has to he repJaced.
Tn'atillg a gas slmam, especially to control pollution,
lIIay 1101 he a lIIolley-maker, but costs can be mlnJ-
mi7.ed, 1101 hy huying the cheapest collector but by
thoroughly ellginecring the whoJe system, as is nor-
mally done in other process design areas.
What data are needed? What equipment might be
suitable? The usual questions that immediately arise
in the choice of a pump or heat exchanger bave weD-
established routes to the answers. By contrast, the
extremely helerogeneous nature of particuJates io gas
slreams has led to a wide variety of equipment for
which engineering principles are either lacking or not
availahle to the practicing engineer; equipment man-
ufacturers must be relied upon for proprietary designs
and for performance guarantees.
Gas.cleaning equipment discussed here will handle
dllst parlicle sizes he tween 0.1 and 100 microns and
conl'cntrations from 0.] to 100 grains! cu.ft. The
micron (,..) is the commonly used IInit of particle-
size measurement and is defined as 1/1,000 mm. or
1/25,400 ill.
Dust concentrations aw usually given in terrn.~ of
graills!clI.ft. of gas (7,000 grains = 1 lb.).
Air deall('rs for fumes with milch smaller part ide
si7.e and loadings are heyond the scope of this article,
as arc comhllstion or catalytic incinerators, gas or
odor absorbers or adsorbers, venlilation-alr cleaners
nnd mist eliminators.
TIle need for gas cleaning may bt- either for
process, proteclion or pro6t. A coUector may be an
integral part of a process such as spray-drYing or an
auxiliary to recover vaJuabJe byproduct. The main
requirement may be safety, as by reducing toxic or
combustible dust. People aod property in the plant
or neighborhood may need to be protected by a good
dust coUection system, or the requirement may be to
Reprinted 'rom CHEMICAL ENGINEERIHe. Jan. 21, 1969. Copyrl8lrt CD ,!I~ by Mcate..HIII Inc. 330 West 42nd St., N- Yo"", H.Y. 10036
-------
20 microns).
t~
Selecting a dust collection systvn is not as straightforward a procedure as choosing
a pump or heat exchanger. Here is a guide to the complexities of the numerous
kinds of equipment available, the jobs that they do, and the way to select wiseiy.
lIIect air pollution laws anu to clean up an unsightly
stack plume.
Equipment Applications
TIle many different dust collectors available today
are summarized in TabJe I, Equ;pmcnt Application
Table, which simplifies a review of the whole col-
lector field. The table is intended to be used along
wilh dcscriptions, illustrations, and efficiency curves
that follow. Hanges and limits tabulated are typical
valucs but naturally may vary widely for unusual
applications. More background is available in the
puhlications listed under "General Equipment" in
Ihc references at the end of this article. Suppliers
can hc found listed in the Environmental Engineer-
in~ Deskbook (Chern. Eng., Oct. 14, 1968) and
should be consulted especially for integrated systems,
packaged units and air cleaners.
Performance of the diHerent types of collectors can
be roughly compared by means of the curves showing
grade or fractional-size efficiency, Fig. 20. The data
were obtained by Stairmandll on one standard test-
dust with characteristics as shown in Table V.
Other performance curves cannot be compared
to these for several reasons. Obviously, equipment
design may aHect efficiency. We must aho consider
CHEMICAL ENGINEERING/JANUARY 27, 1969
that uifferent test procedures give widely uiffering
results on thc same dust; dust loadings tested may
have been different; particle characteristics and evc,f(
particle size may be different. Efficiency curvcs mu~t
be used with caution and are discussed more fuUy
in a later section of this report.
DRY INERTIAL COLLECTORS
A ury collector has certain advantages compared
to a wet collector. If the dust is a useful product,
dry collection saves the cost of reprocessing. Han-
GRAVITY settling chamber-Fig. 1
131
-------
~rn~~ ~rn~~~~liW~~ n a a
dling the collected material can give rise to additional
dust problems. Dry, dusty material has the disad-
vantage of requiring ventilation and if hygroscopic,
caking can he a problem. The cleaned gas will not be
cooled or completely free of fines. Without cooling,
the temperature limits of equipment will have to be
considered. Corrosion will be minimum unless the
fumes contain corrosive mists. Equipment gener-
ally is bulky.
Inertial or mechanical collectors are best suited for
medium or coarse particulates. High dust-loadings
can be handled at moderate pressure drops and
power consumption. Simple construction of this type
of collector results in lower cost and maintenance
than other types. Efficiency js not very high; hence,
for" really clean effluent, some other type of collect-
illg device must be used in combination with or in
place of tllc inertial collector. The inertial or me-
chanical collectors depend on particle inertia in a
gravity or centrifugal force field.
Gravity Settling Chamber
Principle-Dirty gas is directed through an over-
sized duct where velocity drops low enough to let
large particles scttle out hy gravity. (Fig. 1.)
C011l111('lIls--Flow may he horizontal or vertical.
Dm! separation suffers from reentrainment from eddy
currcnh. In the Howard dust chamber, horizontal
shelves or trays have hecn added to shorten the
set.tling path of the particle, improving collection
efficiency, Lilt making cleaning much more difficult.
(>
~
I
I
II
I j
! I
I ~
II
I
i-
II
i I
I-
: I
I
..1
1lIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIiIlIlIlIllIlIdllll!lIllIlIlIIlt1!l1lIlml:IIIIJIIIIIIII1lIlIlJlllllnflUmmlllllmmmuunuKIIKJUIUlnUJlllmmmrmnJllllUltl8lCll18I111111J1Hll8lnlnll1l1!l1l1llUllllllflllnlllliUlmnllllllUnllllllNmllUnmuliliunnunUUIRUnlUlUnl1lUllllllDIlUIIUUmUlllumtlUllllllt1ltlIIIIIIUllllnlllDlllllmIll1lll1llmIllllIlAUUlUUWIIWIMIQUIUlJ'IUI.
Equipment application table-Table I
Pre..ure Loss
Particle Laadlng Collection Utilities Gas Size Space
rvpes of Dust Size Gralns/ Efficiency 0... LIquid Per 1,000 Velocity, Range LImits, ".qu;r.' \
Collecting Equipment Mlcrans Cu. Ft. Weight % In.W.G. Psi. Cfm. Fpm. 1,000 Cfm. (qu2,,, .../
--~------ -
Dry mertlal collectors
Settling chamber >50 >5 <50 <0.2 300-600 None Large
Baffle d'dmber >50 >5 <50 0.1-0.5 1,000-2,000 None Medium
Sklmmin~ chamber >20 >1 <70 <1 2.000-4,000 50 Small
Louver >20 >1 <80 0.5-2 2,000-4,000 30 Medium
Cyclone ;>10 >1 <85 0.5-3 2,000-4.000 50 MediLlm
Multiple cyclone >5 >1 <95 2-6 2.000-4,000 200 $:7...1~j
Impingement >10 >1 <90 1-2 3.000-6,000 None :~, l\":',;
Dynamic >10 >1 <90 Provides 1-2hp. 50
head
Wet scrubbers
Gravity spray >10 >1 <70 <1 20-100 0,5-2 gpm. 100-200 100 Medi", ~
Centrifugal >5 >1 <90 2-6 20-100 1-10gpm. 2.000-4.000 100 ~i3C u.
Impingement >5 >1 <95 2-8 20-100 1-5 gpm. 3.000-6,000 100 Medi'''n
Packed bed >5 >0.1 <90 1-10 5-30 5-15 gpm. 100-300 50 ~eu..J",
Dynamic >1 >1 <95 Provides 5-30 1-5 gpm., 3,000-4,000 50 Small
heed 3-20 hp.
Submerged nozzle >2 >0.1 <90 2-6 None No pumping 3,000 50 Medium
Jet 0.5-5 >0.1 <90 Provides 50-100 50-100 gpm. 2,000-20,000 100 Smell
head
Venturi >0.5 >0.1 <99 10-30 5-30 3-10 gpm. 12,000-42,000 100 Smdll
Fabric filters >0.2 >0.1 <99 2-6 1-20 200 Large
Electrostatic precipitators <2 >0.1 <99 0.2-1 0.1-0.6 kw. 100-600 10-2,000 Large
Note: The terms expressing concentration, or loading, can ba defined as light =-: '/, . 2. moderate = 2 . 5. and heavy = 5+ grains/cu.
ft. Particle size: fine, 50% in 1/.. 7 micron size range; medium, 50% in 7 . 15 micron size range; coarse, 50% over 15 microns.
BAFFLE CHAMBER uses direction change-Fig. ;
The gravity settling chamber is seldom used toda"
but can he desip;ned for a specific applicl'tion-"f"'" \
lation contractors seem to be familiar with them.
Space requirement is large and efficiency low, whU
132
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JANUARY 27, 1969/CHEMICAL n""I'~U.RING
-------
IIIrnaruuuulIlllllllUUUUllllllllllllllllnllllMmnmUlllmlUunmnnruunllUIIIlllllllnmUUlmllllmilUruunllllllllUllU111111l1li1-"""""01'01"
Data required for equipment selection-Table II
Particulate characteristics
'1. Particle size distribution
'2. Concentration-average and extreme values
3. Particle density (and viscosity)
4. Bulk density
5. Moisture content
&. Electrical resistivity and sonic properties
7. Handling characteristics-erosion, abrasion, frang-
ible, flocculent, adhesive, sticky, linty, bridging
8. Composition
9. Recovery value
10. Flammability or explosive limits
11. Toxicity limits
12. Solubility
Gas characteristics
"I. Flowrate-average and extreme values
2. Pressure
3. Temperature
4. Moisture content. condensable vapors
5. Composition and reactivity
6. Corrosive properties
Effluent
'I. Desired emission of contaminant in clean gas
2. Method of disposal or recovery of collected contam.
inant
, Required for preliminary equipment selection.
IIUDillllllllllllllllllllllllllnllHnlllllllllUllIllJllllll11IIIJJUlIUIIIIIIIIIIIIIIIIHlmUIIIIIIIlIlllllUIIIIIIIIIIIIJUIIUIUJI11))(lIIIIIIIIIIIIIIIIIIIII1II1IIIIIIII'I1'IIIIII:I1:IIIIUIIIIIIIIIIIIII1111111
limih t"i\ type to precleaning gas to be fed to a
more efficienl colleelor. A comhination of settlin/-:
ch:l1l1l)('r\ and radianl-cooJin/-: connecting ducts is
ciled ill one tcxt~ as heing used in the metal refining
industry.
--
/
/
/
/
/
,
',Slot for dust removal
at periphery
.- - - - Fixed vortex vanes
. (not shown)
'- - Dust hopper
'-
'-..... - Hopper cleaned
air vent
SKIMMING CHAMBER eTploys scroll-Fig. 3
Baffle Chamber
PrinciJllr-Settling is aided by using momeutum
from a direction change. Gas flow is directed down-
ward through a ehamhcr containing a bailie around
which the gas is deflected; meanwhile the larger dust
part ides tend to continue moving downward to be
collected iI/ a hopper for later use or removal. (Fig. 2.)
(;Ollll/ICHls-This collector takes less space than the
straight-throngh settling chamLer and has sin,ilar
dncicHcy. Olle ell/p-trap (lcsign2 (intended to pro-
tect dowllstream fans from very coarse materials)
has dimellsiuI/s givel/ ;" terms uf the inlet duct
diameter.
Concentrated
dust stream
-- -
lOUVER TYPE collector, with detail showing method of dust removal-Fig. 4
CHEMICAL ENGINEERING/JANUARY 27, 1969
133
-------
~OO$~ ~rn~~rn~uoo~~ D D D
Cleaned-gas discharge
Tangential inlet -',
Conical tailpiece for
smooth transition
- - from downward
to upward spiral
Dust descends - - - - -
walls in spiral
Dust discharge
CYCLONE removes larger particles-Fig. 5
Skimming Chamber
Prindplc~Tbe Jirty gas stream enters a scroll
tangentially; tbe (lust is carried to the periphery hy
inertia. Cuncentrated dusty gas is skimmeJ by slots
and Jed to a dllst hopper or secondary collector. The
cleaned gas ~treaJJ\ from the hopper is combined
wilh that leaving axially from the skimming chamber.
(Fig. :1.)
Cm/l/llcnts-Dry collectors of mediuOl efficiency
,ncb as fbi, one have an exit-gas stream that will
prohahly nol satisfy most requirements of dust col-
lect illg. A ~p('ondary ('ullcdor may well he rell'lired.
tbe skilllJl1ing cbamuer h('ing used to reduce the load
of cuarser particles that are carried into the secondary
collector.
louver-Type Collector
Principle-Gas passes into the wide eml lit ,( wedge
or ('one and IIllIst take a sharp heml in order 10 "scape
through sluts or louvers ill the walls. The lar~cr par-
ticles are carried by inertia to the narrow end of
the chamber where they are purged with a small
fractiun of the gas stream. (Fig. 4.)
Cmllll/cnls- This collector must be followeJ by a
.\ecolld collector, such as ,I high-efficiency cyclone, to
separate the dust from the gas. One author (Strauss)14
shows cone-shaped IOllvereJ collectors followed by
a bame chamber for coarse dust, followed in turn
by a eyclolle for fine dust. The gas purged, usually
134
less than 10%, is returned to the inlet of the louvered
collector and recycled.
Cyclones
Principle-In the most common arrangement, th,'
gas enters the cyclone tangentially at the top of [:.11:
cylindrical section and spirah downward j..,.,., ,.
bottom section, which is usually conical ir, ,'har<~.
Dust particles, which have a greater app!;,~rl L~nfr;f
ugal force than the gas molecules, accumtJ;', :\t '~I,-
wall and are carried down, held agaimt tl,.- I all ' :'
the gas velocity. At the bOllom 01 the C) ci' 1.le ,he:
gas separates from the dust, flows back up:;., .\ ::mal..~r
spiral and exits at the top. Solids are coll"cl~d ;/\ :.
hopper and removed by a rotary valve, screw con
veyor, or other such means. (Fig. 5.)
Commenls-Cyclones are one of the JT'~.' ",;r!pl..
used collectors. The unit is low cost, ha~' ", 1'" ,. , W
parts and can he constructed with refractory hn:"g~
for high temperature, up to 1,800 F. The common
arrangement with tangential inlet, and axial .J.1tlets
for dust and clean gas is shown in the schematic
diagram, Fig.!. Units can be designed for higb
dust capacity at medium efficiencies and medil'm
pressure drop. High efficiencies are obtained with
smaller diameters and higher velocities, Whl"~' i'
turn lake higher pressure drops. Efficiencies of t'lf-
high-throughput and high-efficiency cyclone~ ~.,..,
be compared in Fig. 19. Units may he instaJ;~d i:.
parallel for large gas flows and in series for higher
efficiencies (or for both advantages, in combined
series-parallel) .
Cyclones may have
operate 011 the same
various configurations and stiiJ
basic principle of centrifugal
Axial dusty-gas inlet
with stationary vane ""',
\
\
1
Cleaned-gas I
discharge
,
I
.-
'"
....
I
I
I
\
\
\ Dust hopper
---...
MULTIPLE CYCLONE (and single element)-Fig. 6
JANUARY 27, 1969/CHEMICAL ENG,"'o;~.
-------
separation. Gas entry may be tangential or axial. Gas
exit may hc axial or axial combined with a pressure-
recovery devicc. Dust exit may be with gas purge
or for solids only, with the configuration being axial
or pcrip!H'ra1. The skimming chamber, multiple cy-
clone lllhc~, and lhe Uniftow cyclone are variations
in the slandard design.
Multiple Cyclone
Principle--Since small-diameter cyclones are more
dlicient Ihan Jarge ones (centrifugal force for a
given tangential velocity varies inversely as the radius
of the cyclone), hanks of small (10 in. or less) cy-
clones arc .lITanged in parallel with feed gas from a
plenum chamber. (Fig. 6.)
Comments-The major advantage is high efficiency
-the disadvantage is plugging of the small tubes.
The individual small cyclone does not operate as
cfficiclltly ill multip]c instalJation as it would by itself.
Thi.\ clifTc[('nce arises from unequal gas or dust dis-
trihutio1l I" inlets and reeircuJation of gas from dust
hopper I lack lhrough dnst outlets. Consequently,
multiplc cyclon('~ arc hest u],lainc(] from a manu-
fal'imcr ,,\ .1 COIUpletc unil in onler to ensure good
dc\ign.
1!,IIllJjilillWIIUJlIIIIIIIIIIIIIIIlllIIIIIllii : I' I" 111,1I1I1I,1I1II1I1I1I1I1I1II:1~I:il\f!H\I!I:IIII:i~III:I:, t "III : :l,::::II:'II:I:'" :11I1!1I1~tlUIII::llllllm,;r1l1l11 :um:HIII.~l'IlIl1ntlU:IIIUIJ \I
Equipment selection checklist-Table III
Performance and objectives
Inlet gas volume
Efficiency required
Collected contaminant handling or disposal means
Operatine pressure and allowable pressure drop
Continuous or intermittent operation-frequency of
startups
Surge loads
Guarantees
Acceptance tests
Dust characteristics
Particle size and distribution
Dust quantity per hr.
Sou rces
Handling characteristics-erosion, abrasion, frangible.
flocculent, adhesive, sticky, linty, bridging
Recovery value
Solubility or slurry characteristics including pH
Bulk density
Gas characteristics
Composition, molecular weight, reactivity
CondItions of temperature, pressure, moisture
Soluble or condensable components
Required outlet temperature
Mechanical features
Materials 01 construction
Nozzle orientation
Utility characteristics
limitations on space and weight
proposed location-indoors or outdoors
Insulation
.lllUllUIJT1mnUlllllillIIIIIIIIIIIIIIIIIIIIIiUlIlUlUlllIltnIlIllUUlUmntnmnURnUnnlilllil1i11mnJIIUI1mnmwowmnnnllIJmmnn!Itl!mnOlllll1fflUTUlIlIDUIHII!ItIItI!IIB
CHEMICAL ENGINEERING/JANUARY 27, 1969
-,
Baffle
~ - plate
~
Venturi /
section -
IMPINGEMENT cQllector (detail of one slot)-Fig. 7
01111"" ,"let
Impeller
rJ,,~'lf)n
Cht
-------
~~~~ ~~~~ffi~UOO~~ D D D
..---
'-lean-gas outlet /'-...
- - Scrubbing
liquor sprays
/'--, Scrubbing
'v-' liquor inlet
rl Scrubbing liquor and
~7 recovered dust outlet
....,
I
I '
CENTRIFUGAL SCRUBBERS can be had in several versions-Fig. lOa and lOb
~
Impingement Collectors
1'/ inciplc-Cas n,Jocity is. illcreased in a venturi
.II"! particle IIlumelltlllll carries the particles through
...ll)h II) .1 flat pl.lk \VhCll' thev drop to a collector.
Dml p.lIllck, arc collecl('d 011 .( surface while the
g.t, "IIT.II" i... di\'I'rted alolll,,1 the plate. (Fig. 7.)
Cll//lTlIcnl,l -Collectioll of IItist is simplified with
IIII' cl)llector. ,illc(, liquid IIlcrely rl,lns down the
klfll,. pial" Thcs,' de\'iccs lllay I'Cfluire rappers to
flcl' cI",1 lhat huild, Oil surfaces. If the solids arc
...ticky, II". ,lll'facel "lay bc cuntinually washed by
('i" "I. Illay be rcmovcd as well as particulate.>
. (;orrosive gascs may be neutralized by proppr
choice of ~cruhbing medium.
. The stack efllucllt lIIually will he wdl dto..l.~..,
bul will cOlltaill .>OIlIC ullwelled fines, mists, and .\
,t{'alll phillie.
. The tClltpcralllre allll moisture content of thO!
illlet g;as i, cssclltially ulllillliled.
. Fn'('/.illg cOlldilion,s must he considere<..l.
.lIa/,ards of !'Xplosive dust-air mixtures are
reduced.
. E
-------
Gravity Spray Scrubber
Principle-Liquid is sprayed into the top of the
tower and coarse drop]ets fan by gravity through a
countercurrent flow of the gas being scrubbed. Dust
particles are conected main]y by inertia] impaction
and interception. (Fig. 9.)
Comments-Efficiencies and pressure drops are
low, bllt the scrubber is usefu] for a heavy ]oading
of coarse particu]ates, or for absorption accompanied
hy solids removal. The wet cap .used on top of
foundry cupo]as is a spray and baffle arrangement in
which water both coo]s the baffle and conveys the
collected dust. noiler and process stacks have been
~crubbed with sprays installed in the stack, thereby
avoiding an additional fan and separate scrubber.
Entrainment is contT01led hy using low gas ve]ocities
when designing spray towers, hut this resu]ts in ]arge
equipment. Sprays are se]ected to give ]arge drop]ets
that must be heavy enough to fan counter to the gas
flow, even though they may he further reduced in
~ize by evaporation.
Centrifugal Scrubber
Principle-Liquid is sprayed into the unit and mixed
with the rising vortex of gas. ny impaction and inter-
ception the gas and ]iquid partides combine and
are accelerated to the vessel wan by centTifuga] force.
There they are collected. The wetted wan aJso aids
conection. (Fig. lOa, b.)
Commrnls-A variety of types have been deve]opt;d
ha~ed on difTering of drop]et forming and of pro-
moting (vc!on,c gas action. Vaned baffles (Fig. lOa)
direct ga\ flow and convert ve]ocity pressure to drop-
kt formation energy. Sprays may be instaned axiany
for radially-directed droplets, or circumferentially for
tangentially introduced sprays. For higher pressures
Packing support -
Mist eliminator --
Scrubbing liquor - .
...
/ - Packing hold-down
Floating bed of
- - low-density spheres
----
---
- ----
PACKED-BED scrubber has large surface---Fig. 12
CHEMICAL ENGINEERING! JANUARY 27, 1969
of 400 psig. or so, droplet size is 50 I-' or Jess, instead
of, say, 500 1-"
Impingement Scrubber
Principle- The gas stream, carrying both dust par-
ticles and water droplets from preconditioning sprays,
is directed throu~h perforated plates to impinge on
haffle plate,. Cas ,,"elocity ads to atomize water on
the perforated plate. Enlarged particles are coHected
on vaned mist e]immators and are withdrawn along
with the solids ('oJlected in the liquid overflow from
the impingement plate. (Fig. 11.)
Comments-The scrubber is similar to a sieve-plate
co]umn and uSllaJly has from one to three p]ates, al-
though there may he more. Extra stages can be added
later. Each hole in the "sieve" plate has a bafHe or
"target" above. F]ow is countercurrent. The gas rate
in the perforations is high, 75 ft./sec. or more, and
is used to provide atomization of the liquid on the
plate. Plugging of holes, which may be 1f4 in. or
Jess, is not as much of a prob]em as might be ex-
pected, owing to the agitation as wen as to the gas
preconditioning sprays that wet the underside of
the plate. 50]ub]e gases can be efIective1y removed
a]ong with the dust.
Packed-Bed Scrubber
Principle- Wetled packing provides an impinge-
ment surface that prevents reentTaiI-'ment. The liquor
provides a means of washing off ~ust and convaying
it in a slurry or so]ution. (Fig. 12.)
Comments-Packing may he fixed or it may be a
floating bed of low-density spheres. The advantages
arc: ]ow cost and simplicity, corrosion resistance,
and no moving parts- Dust collecting may be sec-
ondary to direct-contact cooling and gas absorptir)ll.
DYNAMIC wet scrulJber--Fig. 13
137
-------
rnoo~~ ~~~~rn~~~~~ a c a
(;""", 1'1 Ill' rell10ved arc hclow 1 % hy volume.
'1'1" 11 .,,:1\ c'lIuntcrcnrrcnt packcd tower has almost
"" ','.\1"'. I,.",dling capacity, since solids tcnd to plug
II" II," kllig ,IIHI support-platcs, which can then be
,le:llleci "Illy hy removal. Crossflo\\' scrubbers can
1i:1Ilcile cI",t hiding, \1p to .'5 grainsjeu,ft. by wash-
JlI)~ 11" L"T flf the packing with spray nozzles in
SUBMERGED NOZZLE type of wet scrubber-Fig. 14
-.----
. . ~
I..
JET >ulI;,IJi~r ">pirates and collects-Fig. 15
138
parallel flow whilc thc hody of the packing is ini-
gatcd from thc top in crossBow.
In a floating hed of plastic spheres, packing move-
ment helps to free the solids.
Dynamic Wet Scrubber
Principle-Liquid is sheared ~('chanicaJJy to brcak
the liquid into droplets for coJlection b~' inertial im-
paction between droplets and dust particles. (Fig.
13.)
Commcnts-In the simplest form of d:'n:-.mic serub-
her, watcr is sprayed into the suction of a fan, and
the welled impeJler and housing holds dust particles
from rcentraimncnt. Thc efficiency is high for fine
particlcs and utilities arc 3 to 5 gpm./1,OOO dm. and
2 to 4 hp./I,OOO dm.
Another unit, the disintegrator, has .uc;:,t;,;: ,l:!d
stationary hars to hreak lip the water r " r"~(..l1n
into finc droplets. This machine seems to be dis-
placcd hy the venturi today.
Power consumption is vcry high, 10 to 20 hp';
] ,000 dll1., efficiency is correspondingly high. Rotor
spccd is .150 to 750 rpm., and huildup must he
avoidcd to prevent rotor unbalance. Consequentl)',
a pr('clcancr, sHch as a cyclone or centrifugnl ~cT11bh('r
is needed to hold the inlet dust loading on the di~.
iJltegrator hcJow 0..'5 grains/clI,ft., and thc temper
ature helo\\' ]25 F. (Other collectors with m~"h.1f1i
cal1y driven elements and a pool of scrubbing ;iqllid
arc inc1udcd in thc fol1owing paragraphs on suh-
mcrged-nozzle scrubbers.)
Submerged-Nozzle Scrubber
Principle-Gas passing through a nozzle or orifice
is scrubbed by the liquid and also atomizes the liquid
(assistcd in some cases by mechanical means) for
further collection of dust particles on the droplets.
These droplets are removed in a disengagement
chamber, aidcd by bames. (Fig. 14.)
Com ments- This type of conector is taken to in-
c1ude scrubbers that atomize liquid entirely by gas
kinetic energy, as wen as scrubbers in which the gas
merely passes through a mechanicany formed spray.
IIigh dust-loadings can be handled, espedaUy jf thc
units are designed for continuous sludge removal (by
conveyor, screw, etc.). Plugging is prevented hy
designing to avoid close clearances in the area where
dry dust meets the spray. The efficiency curve (Fig.
20) is for a self-induced spray scrubber witholll
mechanical input.
Jet Scrubber
Principlc-Water flow is used in a jet ejector, both
to aspirate dusty air and to provide droplets for col-
lecting particulates. The conditioned-dust and the
water droplets are separated from the gas in a settUng
chamber (which may be bamed). (Fig. 15.)
Comments-An induced draft of a few inches of
JANUARY 27, 1969/CHEMICAL ENGlNriRING
-------
watrr is 1I~lIal h"callse 'hip;her val\1es require very
high walpr ral",\ as w,,11 as exc('s\ive power. The
jl'l sl'IId,I)I'r call h" Ilse,1 whpl"(' it is not economical to
add ,I fall for ,( dmt collection system ami where
,'ill1el Illisl or easily ahsorhed p;as is to he removed
fmlll the gas stream,
VentlJri Scrubber
l'rillf'il'lc-Vv'ater is introduced into the throat scc-
11011 alld atoll1ized hy the high-velocity gas stream,
'1'1", high rplative vclocity hetween the accelcrating
"did p'o 1/('1" "od thc liquid droplet makcs for high
dTicielll'l' h~' ilnpingpment. Collection is aided hy
,'ond,'m,\I,on if tl\(' gas is satnrated in the rcducell-
pn'S\lnl' wclion of tll(' venturi, sincc tI,e solid par-
ti"I"s \I'I'VI' as IIncl,'i for condel"illg in the press lire.
rega;" scdioo. AgglonH'ralnl particles hnilt Oil drop.
Ie" of so J1 or IIlorp call he ('ollpcll',1 with higll
l,ffjCI('\I('Y in a snhse
-------
~m~~ ~OO~~~~~OO~~ a a a
Cleaned-gas outlet
.
.....Reverse-air jets
"I
I"~"
I .
~ Reverse-air
'Jr~~~~~
- - support
Dusty-gas inlet ~
'..., - Dust hopper
Valve ---
Cleaned-gas outlet
Reverse-air
blower - , ,
Dusty-gas j;oIpl
I I Reverse-air nOllle
,..- f(7- travelling ring
I
Reverse-air - ---
cleaning - -
"" - - Dust hopper
Valve----
FABRIC FILTERS with reverse air cleaning (dust collected outside and insi~:.bags2.-=-Fi9. 18
Continuously Cleaned Filters
Continuous cleaning of filter media without isolating
any part of the equipment is accomplished by a trav-
elling hlow-ring or by reverse-air-jets. These cleaning
methods are so thorough and leave so little filter eake
that woven fahrics cannot he used without loss of
efficiency.' lIence felted fabrics are employed.D Air
nowrates of 1.5 ft./min. are usual and result in more
compact haghouses. This kind of filter permits higher
dust-loads, but is more complex, hence has higher
first cost and maintenance. (Fig. 18.)
ElECTROSTATIC PRECIPITATORS
The electrostatic precipitator has the advantage
* Woven lilt.n are porous, and do not filt., efficiently until a cake
of dust is buill up.
-s.~,........
- ""'~b.....tor",*Jf.t""
M-- . . - --.... - H v ...,.,.
U .... .. . ...... - coIK1"", eiKtradI
. ,.".,.,.. WIC-"''''''''''',
8fId... .....
--
..........
H V -. hllJlO1
H V ---.... .-....
""tar""d""'~_"""
.~ C"OIIiKt.........
I ._"--'~
~-=.........,
.-w......,..
---
ELECTROSTATIC precipitator-Fig. 19
140
of permitting dry collection, and is highly efficient
on small particles. A fabric filter might be a first
choice, however, unless the process str~am is hot
or corrosive. If the particulate is coarse, a wet scruh
her is lower in cost. nut the pressure drop for the
filter or scruhber will be higher than for the p.ec}pi
tator, and the scruhber's operating costs are likewise
higher. Capital cost of electrostatic precipitators is
usually the highest of all collectors, but a complete
economic comparison must be made for a true pic
ture.
Principle-The gas between a high-voltage eke.
trode and a grounded (or oppositely charged) elec-
trode, is ionized. Dust particles are charged by the
gas ions and migrate to the grounded collecting
electrode, where they adhere. Mists run off the
collecting surface, often aided by addition of irri.
gation streams. Solids are most commonly removed
by rapping with hammers or vibrators, although re-
moval can be by washing or scraping. Pipe-type
precipitators are used for mists or water flushing,
and plate-types are used for dry collection and large
gas flows. (Fig. 19.)
Comments-Although there is widespread use of
electrostatic precipitators and fundamentals are well.
developed, piloting a precipitator application is often
worthwhile, since particle properties may vary bP.-
tween installations and theoretical efficiency is never
attained. Some common applications are the collec-
tion of fly ash from pulverized-coal-fired boilers,
cement-kiln dust, sulfuric acid mist, catalyst dust in
oil refineries, and steel blast-furnace dust. Efficiencies
are high, as shown in the curves of Fig. 20. Oper-
ating temperatures range from 0 to 700 F. although
units have been designed for temperatures of -70
or + 1,000 F. Pressure drop is small due to low
velocities, but this makes for a large instollntion
JANUARY 27, 1969/CHEMICAL [O\\G~rWI.JUI':f,;
-------
..
-
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,g"
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ill~,
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,- I
-f- Cellular cyclone -
l(~I"~ "
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'h'f" I... .,-
"~'""~"" I
!-<1<' !r.t ~- '!.'!'.IHII ~
",~ ..:.,.>"" i>" ,40. .,j:[;o~
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~
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g,
High.efficiency cyclone t- ~\
J ~
'I I " .~..
"J,O~".' 20: :;.'~/
'\~ ~..}~ "t I ~~.,
,,~ '~I ~ i t.....r ,~~
r-Irrigated electrostatic t- ~t:'f:'r . . '~;~
r- precipitator t- ~j!r., ~l"'" Fa~nc filter ~'I
j 1 .'.. I PJ>.:,~, ~:1V .' I, I, ;~
'" '" - ,'" ,\"10' :,. j fi~, f'.:, '6i i:D .. ;.t'--:..w- ..;1 . , ' ',.'~ ,-.-:l...,
'. ..~ '~~', ,I.) ;:;.:>., "'~~~'if :~~ii
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-
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rv ,-.. ., . .
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Wet dynamic scrubber
t'
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. , :
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-------
moo~~ ~rn~~~~~m~m a a a
Multiple cyclones
I \
Louver collectors
TYPICAL COSTS of various kinds of dust collectors plotted against capacity (costs
ating one or more types of collectors on an existing-
process sidestream or in a new-process pilot plant.
If pilot apparatus can be chosen and operated, the
analysis of particle size distribution of dust can be
ignored. The dust loading will be checked in the
normal course of efficiency measurement, permitting
direct evaluation for simple scaleup. Many suppliers
have pilot-model cotIectors available for rental, often
with some refund on purchase of a full-scale unit.
Installation and operation of a 1,000 cfm. pilot device
may cost from $500 to $5,000 or more, depending
on the complexity of installation and the auxiliaries
that may be required.
Going a step further, before making a choice, some
simple lab work may prove economical in the long
run. Laboratory data can be obtained from an exist-
ing process by collecting dust samples for particle
size determination, either in your plant's lab, or
by suppliers or consultants.
A microscopic count (described later) is tedious
but requires only equipment usually available. How-
ever, collecting accumulated dust from the building
comers or duct elbows, instead of sampling properly,
can be misleading. The particle size may appear Boer
or coarser, agglomeration of particulates may change
the size, or hygroscopic solids may change character-
istics as water is picked up or other contaminants are
included.
Lab data on crudely collected samples can be
obtained quickly and cheaply but will probably have
to be supplemented later by isoldnetic sampling
(described later), depending on the size of the project
and the economic risk that can be tolerated.
It may be feasible to proceed with installation and
plan to modify, supplement, or add stages to the
collector. For example, a venturi with adjustable
pressure drop can be installed, a wet collector can
be added after a cyclom', or more stages may be
added to some types of centrifugal wet scrubber.
Determining the desired emission depends on one
or more factors: air pollution codes, toxicity limits,
and economics. Legal requirements of air pollution
control in the U.S. are very complex, depending on
federal, state and local governments. Laws are COD-
cerned with the type and amount of particulate and
142
gaseous emissions and also the appearance of smoke.
A dust-control system is subject to future, more lim-
iting legal requirements and should be selected with
some thought toward future improvement.
To determine emission requirements of a particular
location, government agencies should be contacted.
The permit system is used by most control agencies
in this country and should be investigated early in
the program. Literature on air pollution is helpful as
a source of pollution laws. (See "Pollution Laws" in
the references at the end of the article.) A digest
of state laws53 (Digest of State Air Pollution Laws)
and a bibliography51 are available from the Govern-
ment Printing Office. Obtaining the information is
simple, but interpretation and compliance may be a
problem, which is not within the scope of this article.
Hazard control may be an added init1al requirement.
Data are available for many dusts and vapors, al-
though new materials may require some lab work.
Dust hazards to consider are explosive concentra-
tions with air, flammability, and toxicity to plant. or
animal life, including radioactive hazards. Vapors in
the gas stream must be checked for explosive limits
and toxicity. A summary of properties is given in
the table "Explosion Characteristics of Various
Dusts."2o It will be noted that concentrations in-
volved in gas cleaning are usually below the minimum
explosive concentration. Recommendations for safe-
guards are contained in the safety codes of the Na-
tional Fire Protection Association.28
A very broad guide to allowable emission may be
drawn from the following. Emission limits under an
early code permitted 0.85 lb. fty ash per 1,000 lb. of
gas corrected to 12% carbon dioxide. This is equal
to 0.48 grains/cu.ft. Newer codes limit emission to
0.25 grains/ cu.ft. Fine particulate matter of 0.01 to
0.02 grains/cu.ft. is the limit for a power plant emis-
sion that is to be invisible. Besides particulate con-
centration, the particle size and refractive index
of the material aHects light-scattering ability.
SAMPLING AND ANALYSIS
Sizing a proposed collector or checking the per-
formance of installed equipment may very' well re-
JANUARY 27, 1969/CHEMICAL ENGINEERING
-------
are for equipment only)-Fig. 21
quire sampling and analysis to determine dust load-
ing at inlet al1(} outlet. Or a sample may be needed
for p:lIti('1c size determination. There is a variety of
tcehn iqncs which can be used, permitting a choice
Jcp('f}(ling on convenience, 'cost or accuracy. A sum-
mary is presented in "Aerosol Sampling and Analyz-
ing J nstrumcnts."GO As will be seen, test equ~pment
choice depends on the process characteristics, so the
investigator must have some ide~. of the ma:;nitude
of thc answers he is setting out to find; for example,
what rate and time of sampling will yield a signifi-
cant weight of solids.
The gas flowrate must first be measured. For most
process gas streams the pitot tube and inclined man-
ometer are suitable. For obtaining a rough measure
nf velocity below] 0 ft./ sec., a vane anemometer may
be used. High velocities in small ducts may be meas-
ured with :HI orifice or a venturi mcter. Methods are
discussed in Perry" and the Western Precipitation
bulletiu WP-50.44
T]lere arc many means of measuring gas velocity
but the standard pitot tube and ddferential pressure
gauge is relatively simple and reliable. The operator
must be careful that the section of duct is straight
for () to 10 duct diametels upstream and 2 to 4
dial1lctcr., do\\'nstrcam, 10 ensure uniform flow; also
that the dust is easily accessible, and that the pitot
-------"
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Process and safety checklist-Table IV
Dirty gas heat-removal or recovery
Startup preheating equipment
Cleaned gas handling-vent or recycle
. W~ste treatment and disposal facilities
Storage requirements
Freezeup protection
Auxiliaries required
Controls and measurements reqyired
Utilities-type and capacity available
layout
Fan location
Access-installation, cleaning, maintenance, sampling
Plant location
Future expansions or tightened restrictions
Economics
Equipment costs
Operating costs
Recovered material value
Approvals-insurance an j permits
Hazard protection-flamrnable, explosive, toxic materials
Electrical classification of area
Pollution control-air and water
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tube is pointing directly upstream. The combined
pitot-stalic tnhe consists of two concentric tubes, one
for illipact pressure and the outer onl') for static pres-
sure. The pressure diJIerence, measured by an in-
clined manometer, is the velocity pressure. The
standard type "L" pitot tube is suitable unless dust
loading or gas humidity is high enough to cause
plugging, in which case, the special type "s" pitot
tube is used. Wet- and dry-bulh gas temperatures
are taken for use in calculating both g;;.s dens;ly
and humidity.
Velocity pressures from manometer
measured in equal areas in the duct
calculate velocities as in Perry.o
The velucities are averaged, and duct flow is ob-
readings are
and used to
Thermometer
.'ell"
Preuure tapa
/'\
,
Porous paper bag
\
\
To e.hauster or vacuum lin.
NULL-BALANCE sampling equipment-Fig. 22
CHEMICAL ENGINEERING/JANUARY 27, 1969
Main duct-
--
1
~
---
Sampling noule.......
-
Gooch tubing
/
/
~
~
Connect to
difrerential manomet.r
143
-------
~~~ ~oo~~m~~oo~~ D D D
tained hy m,dtiplying the average velocity and duct
cro~s-s('ctional area.
To del(~rmille the dust loading in a duct, the method
of iso\.. illd ic samp1in~ is used to withdraw and col-
lcd all dnst in a measured volume of gas, matching
the sampler velocity with that in the main duct and
ensnring .l I epresentative dust sample. There are two
methods of doin~ this. Duct velocity may be meas-
lII"ed and the sampler velocity adjusted to the iso-
kinetic velocity. Or a Bull-balance probe can be used
(Fig. ~2) to match static pressures, thereby matching
Paper, or sintered
(
I
metal, thimble and holder
Canlrol
/ valY8
~
I \
I Vacuum pump
I or ejec lor
T h81'momeler or
Ihermocouple
"
---,
,
----'
/
Rotameter,
gas meter,
or orifice
DuCI and
sampling noule
----
DUST SAMPLING equipment diagram-Fig. 23
,0
.~
~ ~
'..'11~
,~.
,;. \
~
'''r.k~ "
~
DUST SAMPLING apparatus assembly-Fig. 24
Sprinl: plale - -,
-- /-- Hopper
/- Brush
- - Orifice tube
Fan wheel
vanes / / / -
Silting chamber,
Catch basin - ,/ /
Throttle spacer - .::-:'aj -:..
Rotary duct
opening
, Rotor casting
, Symmetrical
-- -- disks
~ - - - - Throttle nut
.~:----Motor
BAHCO CLASSIFIER, cross.sectional diagram-Fig. 25
144
velocities without measuring duct velocity. The
former method is described in several references
3~.3f1.44 and the latter is described by Lapple.40 Se~
also Ref. 44. The sampling train (Fig. 24) is assem-
bled from a choice of components. Thanks to the
growing interest in air pollution, components that
once had to be made by the user are now commer-
cially available.
Equipment is connected as shown in the scl:tematic
arran~ement, Fig. 23, with a sharp-edged nozzle,
usually 1f4 in. or more in diameter of opening, point-
ing upstream. Dusty gas is withdrawn at a rate fixed
in such a manner that the velocity at the face of
the probe is within 10% of the velocity in the duct
near the probe.
The ~as is drawn through the sampling train by
a vacuum pump-or an ejector operating on air,
steam or water-and capable of maintaining a flow
of Ih to 2 efm. as resistance increases in the filter
owing to dust buildup.
The !-(as sample stream must be metered by some
suitahle iustrument, such as a rotameter, orifice and
manometer, nr gas meter. The rate of sampling is
controlled hy a valve for variations in temperature,
vacuum or density.
The dusty gas picked up by the sample probe is
filtered in a preweighed paper or sintered-meta]
thimble. The filters or separating devices used are
usually at least 99% efficient. The probe is traversed
like the pitot tube and held at the same locations with
the sampling flow set to equal duct velocity' at that
location.
A simplified dust sampling may be made on the
exit of a wet scrubber if it is felt that all particles
are Jess than a .'51-' and sampling need not be iso-
kiuetic. Also on a wet scrubber outlet the tempera-
ture of the gas up to the filter must be kept above
the dewpoint hy heating with an electric resistance-
heater. Placing the filter in the probe assembly
(where it is heated hy slackgas) avoids condensa-
tion, loss of sample, or plug~ing in the tube between
prohe and remote filter.
The sample collector is not limited to paper filters
- -------
---+8
ElectrO'latic attraction
I
-,
.
---+
---+
---+ .
---+
---+
.
:
::::e
Inerlial impaction-"'"
MECHANISMS of particle collection-Fig. 26
JANUARY 27, 1969/CHEMICAL ENGINEERING
-------
and in fact, other types may be more suitable. A
description of a variety of such devices is given in
Stern II p. 49713 and Western Precipitation bulletin
WP-50.44 The filter medium can be chosen from
papers, fabrics, porous alundum, or cellulose ester
membranes, thereby permitting selection for special
nmditions-high temperatures, extremely small par-
ticles, low ash content media, or transparency of
media with oil or water treatment after sample col-
If'ction,
Smalfdiameter cyclones can be used to collect
samples if the dust is coarse, or if total dust measure-
mcnt is not important. One manufactu~er (Dustex)
IISCS the cyclone efficiency for simple scaleup (assum-
ing no efficiency is lost in gas distribution) to the
multiple cyclone needed for the commercial-sized col-
lector.
Another common sampling device, the impinger,
consists of a Bat surface with sampJI" stream directed
through a jet to impinge on the plate, usually sub-
merged. Solid particles down to Ip. are determined
after evaporation.
The total gas volume is the product of the rate
of sampling and the duration of sampling time. The
sample weight is obtained, by difference, after drying
and weigl ling. Dividing the sample weight (in grains)
by the gas volume (in standard, or actual, cubic
feet) gives the dust loading of the gas stream..
Efficiency of a collector is the difference between
inlet and outlet loading, divided by the inlet load-
ing. The ASME procedure for calculating efficiency
permits using the weight of dust caught instead of
either inlet or out jet dust.
A particle-size analysis should be run on the sample
collected. Some idea of particle size is a prerequisite
to sekcting a dust collector. There are many ap-
proaches depending on the situation. Adequate facili-
ties may already be available within the organization,
or it may be worthwhile to obtain analytical equip-
ment for the current study, if future gas-cleaning
problems will justify the effort and equipment. On the
other hand, the process being studied may be a
duplication of an existing plant with much back-
ground experience to draw upon.
If amwers are needed wilh a minimum of cost
and time, it may be advantageous to call in outside
analytical. services that can provide the analysis for
less than $100 per sample. Many of the dust collection
equipment manufacturers-if one can be chosen at
this point-.can provide the service.
A summary of size analysis techniques and devices
appeared in CHEMICAL ENGINEERING recently.41
Methods of particle-size analysis are varied to suit
thc natnre of the particulate or ,the needs of the
analyst or the method of sample collection; a com-
plete picture of test methods and devices is beyond
the scope of this article. However, it might be well
to give some specific examples of the commonly used
. Sometimel, loading is reported in g.jcv.m. (1 gra(n/cu.ft. = 2.3
g./cu.m.).
CHEMICAL ENGINEERING/JANUARY 27, 19fi9
~1"'1':" '.~~81 "1
100
~ ':.J7':,.~? j..
, ~, ~.,'
"
I ~
:..- '1]
.: ''!
, 1a
.3
15 ..
j'O
l
'.
: '
o
Average particle diame18r
-
TYPICAL particle-size distributions, (a) normal; (b)
skewed; (c) double peaked probability-Fig. 27
methods that are applied in dust collector work.
The Bahco Micro-Particle Classifier is a COIn-
bination air centrifuge-elutriator, and is an ASME
standard for particle-sizing.34 A weighed sample of
10 to 20 g. is charged into the hopper, Fig. 25,
and introduced through a feed mechanism into a
spiral of air having suitable tangential and radial
velocities. A portion of the sample is carried by cen-
trifugal force against the air flow and toward the
periphery of the spiral. The remail1Jer of the sample
-the smaller, lighter particles-is carried with air
flow toward the center. The air is pumped through
the unit, by means of an integral fan impeller, at a
rate controlled by adjusting the air inlet orifice. The
residue is weighed after removal of a light fraction,
---
.,
Mode
'1,6
..
145
-------
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Calculation of collector efficiency-Table V
Electrostatic
Particle Size Particle Size Fraction 01 Cyclone Percent Precipitator
Distribution, Midpoint 01 Total Dust EffIciency Dust Dust Efficiency Dust
Microns Range, Microns in Range, % at Midpoint, %. Collected Emitted, %t at Midpoint, % Collected,%
----
<21/2 1% 12 X 33.5 4.0 50.3 X 77.0 38.7
2%-5 3% 8' X 64.5 5.2 17.6 X 90.5 16.0
5-7V2 614 6 X 76.7 4.6 8.8 X 94.0 8.3
7%-10 8% 4 X 84.2 3.4 3.8 X 95.0 3.6
10-15 12% 8 X 89.3 7.1 5.7 X 95.5 5.4
15-20 171h 7 X 92.0 6.4 3.8 X 96.0 3.7
20-30 25 10 X 94.3 9.4 3.8 X 96.5 3.7
30-40 35 10 X 96.0 9.6 2.5 X 96.8 2.4
40.60 50 15 X 97.3 14.6 '2.5 X 97.7 2.4
60-75 67% 10 X 98.5 9.9 0.6 X 98.7 0.6
75-104 891/2 7 X 99.1 6.9 0.6 X 99.2 0.6
104-150 127 3 X 100.0 3.0
84.1% 85.4%
Data are Ihose 01 Stalrmand (ReI. 12).
"Efficiencies as read 1rom an enlarged curve.
tCalculatin~ em.tted dust from collected:
Percent 01 I'll micron dust emitted = 12 - 4.0
100 '::""84.1 = 50.3%
Calculating combined efficiency:
Cyclone Iraction emitted = 1.000 - 0.841 = 0.159
Precipitator Iraction emitted ~= 1.00 - 0.854 = 0.146
Combined fraction emitted = 0.159 X 0.146 = 0.0232
Com Dined Iraction collected = 1 - 0.0232 = 0.977
Combined percent collected = 97.7%
',IIIIiIll"ill'lill"""""illllll"Ili"IllIllIllIIllIlIllIllIll""llllllllllllllllllllm"IlI,IIIIIIIIUIiIIIIIIUllillilllllllnmllllll'IIIIIIIIIIIUlilDlil1llW1lWmUmIUIIJllffiI~uIIUl1IIII1III1U1U11lIllnUU:~IUlUIIIUIIIIIIIII1IIIIIIIIIIIIIIIIIU;UIIIIIIIIIIIIIIIIIIIIIIIWlnmmUWlUlUlluIIUIIIIIIIUIIIIUDllUIR1IIIIInIIllWWUIIIIwu:numuuInnUIIIUUIInIllIllUIIIIIIIIIIIIUlIIIIIIUlUUl~IL11
"nel III(' light-cut weight is uetennined by difference.
Th" prll'("~ " r('[water] to obtain nine fractions. Each
IIIII",{, "'II' ilL: '"lIst 11(' cahbrat('d on a dust of known
'1/.1' d"lrdll,lioll alld the termina]-veloeity values as-
,igrl/'d.llic d,'vdopment of standardization tech-
IIiq'!'" .11 I' dl'CIIS,crl hy Cranda]J.85
Ol!"" "".flll methods incJude cJectronic counting
II, till' (:"lIltn counter in which a suspension is put
1111,,,,,-,1' .," ljH'rtllre, essentially une partidc at a
lillit'. . 1110 {'Iectronic recordin~ of each part/de hy
1/.1',
TIll' ",,,,',,de impactor projects partides through .\
,d "fll" , "],,te where large particles arc coUected,
111(' fillc" ).!"'lIg on to the next stage.
":1uIOl,1I101I is applie(] in the Roller analyzer on
thc l'nn('iplc of the settling chamber deserihed under
collector" lI\ill~ an airstream to remove a fines irac-
tion. dcpl'lIding 011 velocity. These methods and others
are revif'wed in Perryn as weU as, others.13. 48,411
A "ie\ j' ,haker ('an provide several particle size
I'ange, uown 10 50p. particles (43p. equals 325 mesh).
About 100 g, "~f sample are needed. There are some
limitatjon.,: thin, flat lIakes may give artificially large
weight fractiollS of the larger partides, needle-like
crystah IIlay conversely appear in the analysis as
~maller SiLCS, some materials finer than 150#, may
lIocclllal{', and other materials may be degraded.
The ,ievc analysis should he supplemented by a
rOlcro,('()!>JC examination to check partide shape. In
146
the particle sizes hetwecn 0.2 anrl lOOp. t]lC optical
microscope can he used without sieves. The method
is ]a!Jorious but can he simpJified by using photo-
micrographs or hy projecting the image of the par-
ticles on a screen, T}leoretical and practical aspects
are covered in detaiJ in the Jiterature.45
An important property needed for seJecting an
electrostatic precipitator is the clectrica] resistivity
of the dust to he handled. The measurement can
he omitted if .\ prccipitator is commonly used for
the dust or if the equipment designer is otherwise
familiar with it.
Several lI.ethous lor partic1e resistivity measure-
!IICllt are (Jiscussed in White,:!O and resistivities of
""ne representalivc dusts and fumes are given. A
.;tandan] method aiong with apparatus construction
ddails is given in the AS~IE Power Test Code 28,34
and ill the API manual, E]ectrostatic Precipitators.28
MECHANISMS
Mechanisms governing the eoUection of partieu]ate
matter klVc heen studied singly and combined but
do not serve as a means of classifying eoJleetors, since
there may be more than one mechanism at work.
Opcration of a collector is considered to proceed in
three phases: (1) depositing of particles on a coJleet-
ing surface, (2) retaining solids on the surface, and
(3) removaJ. Parameters describing the mechanisms
JANUARY 27, 1969/CHEMICAL ENGINEERING
-------
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Over.all cost of gas cleaning-Table VI
Efficienc)' Water Total Total
on Average Power Required, Water Maln- Annual Annual
Standard Pressure Installed Cost, Gal/I,OOO Cost tenance, Cost, Cost
Collector Type Dust, % Drop, in w.g. Cost, ~ $fyr. Cu. Ft. $/Yr. $/Yr. $/Yr. t/(Yr.)(Cfm.)
----- -"----
Dry
1. Louver collector 58.6 1.7 34,500 1,560 300 5,310 8.9
2. Medium efficiency 65.3 3.7 25,000 3,380 200 6,080 10.1
cyclone
3. High efficiency cyclone 84.2 4.9 48,500 4,520 200 9,~70 16.0
4. Multiple cyclone 93.8 4.3 52,500 3,960 200 9,410 15.7
5. E.lect rostatic 99.0 0.9 233,000 2,000 1,300 26,600 44.4
Precipitator
6. Fabric filter, shaker" 99.7 2.5 165,000 3,740 10,000 30,240 50.4
7. Fabric filter, envelope" 99.8 2.0 152,000 3,380 9,500 28.080 47.0
8. Fabnc filter, 99.9 3.0 231,000 7,920 19,000 50,020 83.6
reverse jet
Wet
9. Submerged Nozzle 93.6 6.1 66,700 5,640 0.7 1,010 700 14.020 23.3
10. Spray Chamber 94.5 1.4 139,000 4,760 21.7 31,250 1,000 50,910 84.8
11. Impingement 97.9 6.1 82,200 5,800 3.6 5,190 1,000 20,210 33.7
Scrubber
12. Wet Dynamic 98.5 136,000 45,400 6.0 8,640 700 68,340 141
Scrubber
13. Low energy venturi 99.7 20.0 107,000 18,820 8.4 12,100 1,000 42,620 71.2
14. High energy venturi 99.9 31.5 117,000 29,740 8.4 12,100 1,000 54,540 91.0
Notes:
The installed cost includes equipment, auxiliaries. such as fans, pumps, and motors (but not including solids disposal oquipment). ::;ite
preparation and Installation. Installation charges are 100% of all equipment except electro5t~ttc precipators and dyna'ntc scrubbers
which are 50%.
Pnce. are adjusted to 1968 with a Marshall and Steven.lnde. at 273. rhe Bnti.h pound is taken at $2.84 U.S.
The co.t 01 power i. taken at $0.01 per kwh. Efficiencies of fans and motors are assumed 60%. Water co.t i. $0.05 per 1.000 gal. and
reported u.age CO'lverted from Im~ "iat (assumed) 10 U.S. gallon.. (Data are from Staormand. Ref. I!.)
--Maintenance charges include bag changes, once per year for envelope-type and twice for shaler and reverse-let filters.
,111~llnllll!nr[:lilll1lllllllll'lllllll11nfmllllllllllnl1IIII1IIHI!!lIllllllllllllltllllllmmnlll11lln!llllllllllllltItUIIIil111\lIlllllll1!!lIlIlnl1llnnII01mI!lUD~IHUllIll1mmllnmUlllll1!llIlllml!UIDnnmmmrnUllnnltIlIIIUI1IIIIIIUlIIIIIIIJ!IIIIIIJ\!lIIIIIllllllllllun1111111'11111111111(11111111111111111111111111111111111111111\l1111111111I11;11111111I1111111111111'1111111111:1!111111'1'111:111111111':111111111'11
"f depmition or co11('ction have been described by
Lnndc :lnd Lapple.IH (a table of parameters is re-
prodnc(:d in Perry, p. 20-6.'5H) and are generally de-
,nihcd helow as a mcans of nnclerstanding operating
prin("iplrs of co11ectors.
Crrll'itlj Sl'Itling- 1'h(' weight of particles may be
cnongh 10 pc'rmit settling from a moving gas stream.
wh/:rc I he dmt is more than SOIL. in a gravity settling
chaml,,'r or ,I haffie chamber.
Centrifugal Sepamtinn-Particles in a vortex gas
lIow an' wp"ratecl hy centrifugal force and arc
dirt'df:d to the outer wa11, as in a eyclone or cen-
trifllga' ,cruhhcr.
DirtTt IntNccptinn-A fluid stTeamline curving
arollnd ;11\ ohstacle such as a filter element or water
droplet .nay carry a particle within contacting dis-
tance "f the ohstacle, and the collision will atTest the
part iclt. on the element or droplet. See Fig. 26,
Mechanisms of Particle (;ollection.
!tu;rtiallmpactinn- The inertia of the particle causes
it to continue in its path rather than follow the stream-
line cllrving around the obstacle, thus pennitting
contact of the particle with the obstacle,
DiffusioTUll Deposition-For particles smaller than
0.11' at low velocities, molecular impacts of Brownian
CHEMICAL ENGINEERING! JANUARY 27, 1969
movement defied the p,1th of the partic),. increasing
chances of f:"J1isio1\ with filter e]{'mcnts ,,]' water
droplets.
Electrostatic l'n-ri!}ilation- A c(,11ecl"r hod v or ,I
particle, or hoth, Inay ha\'e .\ static ch.lrgc that wilJ
introduce a force tn affect the movement of the
particle.
SAMPLE PROBLEM
Over-all co1ledion effi('ieney can be r'a1culated b"
IIsin[!; a co1lcclor dRciency curve in (,(Hnbilla!io))
with the particle size dislrihlltion curve. provided I"at
tl,,\ rnethod of particle )lZC loeasnrcmellt is the, 11111'
for hoth cnrv('~.' Calculat10m are ,h"wl1 111 Tal.l" V
for a high..efflciency cydone follnwed hy :m electro-
stalic prceipitatnr. Data arc from Stain-nand.11 The
test dust used compares to a typical fly ash an,! is
~ivell in Table VI, Standard Test Dust Characteris-
tics. The efficicncy curves used are those showu in
Fig. 20.
From the collector efficiency curve choose several
efficjenci~s and the corresponding ranges of particle
sizes. From the size distribution curve (or table. in
this case) obtain the percentage of dust within the
147
-------
m~~~ ~rn~~rn~~oo~~ a' a a
. <~'. »~, :~~
40
20
~
.~ 10
Ii'
.;; , S
.J
u
i
-------------
.. ,.: '.~:I;;
. '
LOG. PROBABILITY curve for particle.size distribution of
above figure-Fig. 29
50
7.
OVER.ALL COST of gas cleaning (StairmandU)-Fig. 30
148
'i~
~~
,;
~~
size increment. For example, 12% of the total dust
is less than 2% p., and the midpoint of the range
is 11/4 p.. The cyclone efficiency is 33.5 % at 1 ¥4p..
The cyclone has a collection efficiency of 84.1%
and emits 15.8% of the inlet dust. The electrostatic
precipitator collects 85.4% of the cyclone emission.
The combined efficiency is 97.7%.
EQUIPMENT COSTS
Costs shown on Fig. 21 are manufacturers' prices
for dust collectors only. System costs must be de-
veloped for the individual case, adding the cost of
freight, foundations, supports, erection, and auxiliary
equipment. Collector costs may be adjusted for spe-
cial materials of construction. The cost basis year is
1968. (Marshall and Stevens Index = 273).
For anyone type of collector, price may vary
widely depending on the required duty. The costs
presented are for "typical" applications suitable for
a preliminary comparison. Where costs of systems
are of the same order of magnitude, it is probably
worthwhile to obtain quotations for each dust col-
lector.
Over-All Cost of Gas Cleaning
In an economic comparison between different col-
lectors for a particular application, the efficiencies are
likely to he different. The higher cost for better col-
lection can he compared with the cheaper installa-
tion, as was compared in Table V. Costs above those
shown tend toward an uneconomical equipment choice,
while those below tend toward being a good buy.
The original data for this figure were presented
by StairmandJ~ and are adjusted to current U.S. costs
in Table VI. Stairmand developed the operating costs
of the various collector systems cleaning 60,000 dm.
gas at 68 F. with an inlet dust-loading of 5 grains!
'cu.ft. of the standard test dust given in Table V,
with 30% less than 10 p. particle size.
It is interesting to note the high-cost units are the
spray chamber (with a high water-rate) and the
dynamic scrubber (with a high power-rate). Also,
the' electrostatic precipitator may have a high first
cost but efficiency is high and power costs are reason-
able.
CHOOSING A COLLECTOR
Let us look at the selection of a collector from
meager preliminary information. Take as an example
a process in which organic chemicals are spray-dried
and collected hy a cyclone, the dusty gas then going
to a spray tower. It is desirable to replace the existing
inefficient wet collector to meet air pollution abate-
ment requirements and to recover product.
Material-balance calculations of product recovery
efficiency can be used to determine dust-loading
and water evaporated in the dryer. Microscopic
counts of dust samples collected downstream from
'JANUARY 27, 1969/CHEMICAL ENGINEERING
-------
the cyclone give particle size. A manometer can be
he used to measure pressures and, with the fan
curves, the gas flow is determined.
State air poJlution laws fix the emission based on
stack height and distance from the property line.
A summary of data looks like this:
Dust loadiuJ:: to collector 50 to 200 Ib./hr.
J'.uticl" size -Product A 50% < 30 iJ
Product B 50% < 20 iJ
Product C 50% < 5 iJ
Ga3 flow at inlet condition. 20,000 ctm.
Gas temperature 250 F.
Cas humidity 3,000 lb./hr.
Dust cmlHsior, allowable from collector 20Ib./hr.
Convorlinp; the dust loadin~ to j!;rains/cu. ft.:
ZOO lb. Kr. 1 min. 1 hr.
-- X 7,000 -- X ---- --- X --
hr. lb. 20,000 cu.ft 60 min.
= 1.17 gr./cu.ft.
The rcquirement is to emit no more than 20 lb./hr.
from a maximum of 200 lb./hr., or 10% emission.
Collection efficiency is then 90% for a dust loading
of a Jitt],; more than 1 grain/cu.ft. of particulate
with a mean particle diameter of 5 p..
From the note on Table I, we find that the load-
ing is "light" and the particle size "fine." From
the table in Ref. 7, Industrial Collector Applications,
Lines 4 and 39 favor high-efficiency centrifugals, wet
colledlJrs and fabric filters.
Cyc-Jo!les are unsuitable, which is evident since we
are colleding dust that already has passed a cyclone.
EIcOrostalj(; precipitators are not likely since the
gas-handling capacity is somewhat small for good
operating efficiencies, and also the electrical reo
sistivity of an organic dust will probably be too
high. Multiple high-efficiency cyclones are smal1
in diamr.ter and subject to plugging with sticky
organics. Fabric filters are excel1ent collectors for
fine rnatPTial~, especial1y when we would like to
recover usable product, but we should keep the
,ticking prohlem in mind. Wet scrubbers will give
.l clean stack but with a wet plume; the recovered
product will he degraded in value, since it will have
to he dried again. Product value is 2t/lb. dry and
l~/Ih. wet.
Hef~rring to Table I, Equipment Application, we
can clloos~ centrifugal, impingement and venturi
scruhhe, s. Other ~quipment types are excluded be-
eause, let us assume, they arc unsuited for scrub-
hing with dust slurries. Recovered dust will have to
he recycled to build up concentration for economical
recovery.
We will compare each selection hy picking the
operatinlt values of pressure losses and liquid rate
at midrange. Efficiency is read from the curves of
Fig. 20.
The r(,~lIlts of comparing the selected col1ectors
are show II in Table VII. It must he emphasized that
this is a preliminary choice only. Added costs such
as tanks, hag replacements, larger fans and mainte-
nance cosls, have heen ignored. The happy factor
CHEMICAL ENGINEERING/JANUARY 27, 1969
IIIU91llUmanmnJIIURlllllumOlUtr.nrnlnlnUIIJIIIIIIUOlniIUlIIIIII)!IIIIIIWIllnUllllI!nmlnlUlUlnullunruulIlll1llUlUIUlnrnmnuHntlJllUl1l1lumnuJlJUUJffiIIlItnll,IIlf
Example of collector selection-Table VII
Wet Scrubbors
Contin-
IIOU&
Fabric
Filter
----------~--_.
Centri- Impinge- Venturi
fuga! ment
--------- -
.--- --- -- -
---._- --
1. Efficiency
2. Pressure Ins"..
liquid, pSI.
3. Liquid rate, gpm.
4. Pressum l:Jss-
gas, ill. w. g.
5. Power reqUl~"d
gas, hp.
6. Power requir€'d--
liquid, hp.
7. Power cost. $/yr.
8. Equipment
cost, $/yr.
9. Total cost, $/yr.
10. Recovered product
value, $/yr.
11. "Return" (line 10
u line 9), $/yr.
12. Over-all cost from
Table VI by inter-
polation $fyr.
13 Return (I:ne 10--
line 12), $/yr.
97
99.6 >99.9
94
60
100
60
60
15
100
20
5
<1
4
158
74
74
79
4
5,000
2
9,600
7
4,800
4,400
1,000 1,200
5,800 6,200
15,000 15,500
2,000 2,200
11,600 6,600
15,900 32,000
9,200
9,300
4,300 25.400
3500
5.000
9,300 15,200
11,500 10,500
6,600 16,800
Notp-s
System pn'Shur" without, collector = 10 in. W.K.
dm. X p.
Fan hI'. = -- - - - - = r; ') X P
6,3S!i X 60% Eff. . .~ .
1'111111' hr-
~Tpjn. '/ H~. ',' 2.:1 i. PA;
3,Hf;u '."; !)O('~. j':ff.
= ().OO i 2 >: v:pm. ;v p~i.
Eleclrie CO"\. =
hI.
hr- X f\.O(}ij
!.wh.
$
)" O.OJ kwh. ~~ 60 X hp.
" 0.71.;
hr. hr.
.'0'1".
Installed ",,,t 200~~ '< l'quiprnellt cost from Fip:. 2 Y
JO~~ (kpn'"iaLivlI/yr-
1lI1II1I1I!!IIUlIII!!!IIII1U1i1ll1ll11ll11l'IIIIIIIIIIIILJllliUuHlIIHIJI!IIIIIII!!UII:UIJJUIlIUIiIwnmUIHlHltlllllllDllJUUIUJIIlwm:muuumWUUlBunlllllUllllllUlJUUnlilimmlllllll
of a tax credit for pol!ution-eontrol equipment is also
omitl('d. I'm the s~_ke of simplicity, the gas-handling
requirement is at actual conditions rather than at
~tandard ('onditium
An alternative method lor quick comparison is the
use of Table VI to abtain the over-all cost of gas dean-
ing as shown 011 Line 12, Table VII. The two costs
for each collcdOl are different, especially in the case
of the ha~ collcdor. Imt looking at the recalculated
"return" )/"I(h 10 the same conclusions. The fabric
filter j,\ pmbahly a gOO() selection jf product will not
cake on the hags or if product cross-contamination
docs lIot require changillg hags. A low pressure-nrop
wet scrublwl, :;",.11 as thf.' centrifugal or impinw~-
149
-------
mm~ ~OO~m~OO~'a aa
ment type, is a second choice. The high pressure-drop
venturi is an excellent guarantee of meeting pollution
codes, but is costly. .
References
Oeneral Equipment
1. Danlel80n J.A., Ed., "Air pollution Engineering Man-
ual," U. 13. Dept. ot Health, Education and Welfare,
Public Health Service Pub. No. 999-AP-40. WaBhlng-
2. ~.'I'I'r Di~ilutlon Manual," Part I, Evaluation (1860),
Part II, Control Equipment (1968), American Indus-
trial Hygiene Assn., Detroit, Mlch,
3. "ASRAE Guide and Data Book," American Soc. ot
Heating, Retrlgeratlng and Air Conditioning Engineers,
4. }~;ge~::n, YJf.:kEJ.~6'~Fan EngineerIng," 6th ed., Butralo
Forge Co., Buffalo, N.Y., 1961.
5. Hemeon, W.C.~.. "Plant and Process Ventilation," In-
dustrial Press, New York, 1963.
G. "Industrial Ventilation," American Conference of Gov-
ernmental Industrial Hyglenl8t8, 10th ed., Lan81ng,
Mich., 1968.
Kat.e, J.M., Heating and Ventilating, 61, No. 10, pp.
77-82, Oct. 1954.
8. Montros8, C.F., EntraJnment Separation. Chern. Eng.,
60, No. 10, pp. 213-236, Oct, 1953.
a. Perry, .I.H., Ed., "ChemlOl\l Engineers' Handbook," 4th
ed., McGraw-Hill, New York, 1963.
10. Smith, J.L., Snell, H.A.. Selecting Dust Collectors,
Chern. Eng. Progr:.J. 64. No.1, pp. 60-64, Jan. 1968.
11. Stalrmand, C.J., ueslgn ana Performance of Modern
Gas-Cleaning EquIpment, J. 01 the Ind, 01 Fvel8 (Lon-
don), 29, No.2, pp. 58-81, Feb. 1966.
12. Stalrmand, C.J., Removal ot Grit, Dust, and Fume from
J~xhaust Gases trom Chemical Engineering Processes,
The Chern. EngiMcr (Oreat Britain), 194, No. U, pp.
310-326. Dec. ] 965.
13. Stern, A.C., Ed., "Air Pollution,': 2nd ed., 3 vol. Aca-
demic Prp.~:;. New YOrk, 1968.
14. StraUB". W., "lndustr al GaB Cleaning," Pergamon
I'r.,s8. New York, 1966.
Mpeclftc )I:(lulpment
1:' nCH Ald-to-Indu8try 500-320, "How to Reduce St..ck
DU8t trom Small Stationary Plantl," Bituminous Coal
Hesearch, Inc., Pittsburgh, 1952.
16. BCH Ahl-to-Industry 600-330, "Stack Sprays to Reduce
DU8t Eml8slon During So",t Blowing," BItumInous Coal
He8earch, Inc., Pittsburgh, 1967.
17 Boucher, RoM.G., Ultrasonlc8 In Proce8slng, Ohern. Sng.,
88, No. zO, pp. 83-100, Oct. 2, 1961.
18. Boucher, R.M.G. Weiner, A.L., Inlluence of Large Am-
plitude Sound Waves on Aerosol Scrubbing, Ai,. Sng.,
Jan., 1963.
1 a. Lunde, K.B., Lapple, C.E.. DU8t and Mist Collection,
Chern. Eng. Progr., Vo!. 63, No.8, pp. 385-391, Aug.,
1957.
20. Mark8. L.S,,- Ed., "Mechanical Engineers' Handbook,"
5th ed., Mcuraw-HIIl, New York, 1951.
21. McCabe, IJ.C., Ed., "Air Pollution, Proceedings ot the
U.S Technical Conterence on Air Pollution," McGraw-
HIli, New York, 1952.
22. Mechanlp.al DU8t Collector Selection and Pertorma.nce
Evaluation Guide, Inte>rmatlve Report No.4 of '1'A-5
Committee. J. Air Pollut. Contr. Aa.n., 18, No.7, pp.
475-477, Jt'ly, ]968.
23. NatIonal Fire Codes, Vo!. 3, "Combustible Solids, Dusts
and Expl08lve8," National Fire Protection Aun., 8os-
te>n, 1967.
24. Pozln, M.E.. others, Appl. Chern. (U.S.S,R.), &e. pp.
297-302 (1957).
25. "Hem oval ot Particulate Matter From Gaseous Wutes:
CyGlone DU8t Collectors," American Petroleum Inst.,
New York, 1955.
26. "Hemoval ot Particulate Matter From Ga8eou8 W8.8tea:
Electro8tatlc Preclpltator8," American Petroleum lnst.,
Np.w York, 1958.
27. "Removal ot Particulate Matter From Gases by Flitra-
28. ~,'R~;:;!v:.Je~ic~~rr.~~~~~~u~,.W::'F~Oe: J~:OU~9~i.et..:
Gravity, Inertial, Sonic, and Thermal Collectal'8,"
American Petroleum Inst., New York, 1969.
2~. "Removal ot Particulate Matter From GII.8eOUI Wutes:
Wet Collec~ors," American Petroleum Inst.. New York,
1959.
30. White, H.J., "Indu8trlal Electrost8ltlc Preclplta.tlon,"
Addl8on-Wesley Pub. Co., Reading, M:a88., 1983.
8.mplln~ and Evaluation
31. "AII' Sampling Instruments for Evaluation of Atmol-
pherlc Contaminants," 2nd ed. American Conterenca of
Government Indultrlal HygIenists, Clnclnn..tI, ties.
32. ASME Power Test Code 21, "Dust Separ..Ung AJlpa-
ratus," AmerIcan Soc. ot MechanIcal En.8'lneers, IfU.
33. ASME Power Test Code 27, "DetermIning Dust Con-
centrations In a Gas Stream," AmerIcan Soc. of 14e-
chanlcal Englneera, 1967.
34. ASME Power Test Cods '28, "DeterminIng the Proper-
ties ot Fine Particulate Matter," American Soe. of 14e-
chanlcal EngIneers, 1966.
35. Crandall, W.A., "Development ot Standarda for Deter-
mining Properties of FIne Particulate Hattsr," Ameri-
can Soc. ot Mechanical Englnesl'8, 1964.
150
36. grlnker, P., HaJtch. T., "IndustrIal DU8t," 2nd ed., Mc-
raw-Hill, New York, 1954. i
37. Dwyer, J. L., "f:ontDmlnation Analysl8 and Cor.trol,'
ReInhold, New York, 1966.
38. Graham, A.L., Hanna, T.H., The MIcro-Particle Clas81-
lIer, Ceram. Age, Sept. 1962.
39. Industrial Ga8 Cleaning Inst.t_"Test Procedure tor Gas
Scrubber8," Pub. No. I, Rye N.Y 1964.
40. Lapple, C.E., HeaUng, P'ping and' Air Cotl.dHioning, 16,
pp. 410, 464 678, 636 (1944) ; 18, p. 108 (1946).
41. Lapple, C.E., Particle-SIze Analysis and .\nalY7.eM,
Ch.em. Eng., 711, No. 11 liP. 149-156, May 20, 1968.
42. Magill, P.L.. other8, Ed., "Air pollutlon Handhook,"
McGraw-Hili, New York, 1956.
43. Orr, C., Jr., Dallavale, J.M., "}o'ine Particle Mea8ure"
ment," Macmillan, New York, 1959.
H. Western Precipitation Corp., Bull. WP-50, "Method8
tor DetermlnaJtlon of Veloclty, Volume, DU8t and Mist
Content ot Gases," 7th ed., Los Angele8, ] 968.
Aero801 Theory
45. Cadle, R.D., "Particle Size Detennlnatlon," Inter-
8clence, New York, 1955.
46. Fuch8, N.A.. "The Mechanlc8 ot Aerosols," Pcrgamnn
Pre8s Ltd. Oxtord, Eng., 1964.
47. Green, H.i.., Lane, W.n., "Particulate Clout!.: D1I8t8,
Smoke8 and Ml8ts," 2nd ed., D. Van Nostran'.. New
York, 1964.
48. Ranz, W.E., Wong, J.n., Impaction ot DU8t and Smoke
f:~~~c~~s52.I"d. Eng. Ohern., H, No. .6, pp. 1371-1381.
49. Semrau, K.T., Correlation ot DU8t Scrubber Efficiency,
i961~r Pollut. Cont. Au"., 10, No. I, pp. 200-207, Jan.,
50. Whitby, K.T., LIu, D.Y.H.. Dust (Engineering), "KIrk..
Othmer Encyclopedia ot Chemlca.l Technology," 2nd ed..
Vol. 7, Wiley, New York, ]965.
Itollutlon Law.
01. "Air Pollution Publications. A Selected Bibliography
1963-1966," U.S. Dept. of Healt!> , Edu('atlon, and
Weltare, P"bllc Health Service Pub. No. 979, .Wash-
Ington, D.C., 1966.
52. Bonn, D.E., .Vet-Type Dust Collector8. Chern. F;ftg.
Progr., G9, No. 10, Pr,. 69-14, Oct., 1963.
53. "Digest ot State A r Pollution Law8, 1966 Edition"
U.S. Dept. ot He8lth, Education and Weltare, PlIbllc
, Health Service Pub. No. 711, Washington, D.C.
a4. HUghson! H.V., Controlling AII' Pollution, Chern. 1-,'nl/.,
78. pp. 7 -90, Aug. 29, 1966.
55. Yocum, J.E., Air Pollution Regulations, Chern. EnD.,
69, No. 15, I>P. 103-114, July 23, 1962.
Acknowledgements
The tollowlng companies 8upplled Intormatlon and illus-
trations tor thl8 report; the numbers In psrenthese8 are
figure numbers tor llIu8tratlon8 u8ed.
Aerodyne Development Corp. ; Aerodyne Machinery Corp. ;
The AIr Preheater Co., Inc.: American All' Filter Co., Inc.
(8, 13, 17); American Standard's Indu8trla.1 Product8
Dep4.; BitumInous Coal Research, Inc,: Buell Engineering
Co.. Inc.; BuffaJo Forge Co.; Carborundum Co.'s Panl{bom
Corp. (H) ; Carter-Day Co. ; The Cellcote Co. ; Centrl-Spra/'
Corp.; ChemIcal Construction CO.'8 Pollution Control Dlv -
810n (3.19, 3.20) ; Combu8t1on Englneerlnl{ Inc.'s Raymond
Dlv.; Croll-Reynolds Co., Inc.' The DeVilbiss Co.: Dletsrt
So. (26): The Ducon Co., Inc.: Du8t Suppres810n and
Engineering Co.; Dustex Corp.; Fisher-Klosterman, Inc.:
Flex-Kleen Corp.; The Fly A8h Arrestor Corp.; General
American Transportation Corp.'s Fuller Co.; Hell Process
Equipment Corp.; Indu8trlal Sale8 Enl{lneerlng Corp.; The
Johnson-March Corp.; The Kirk & Blum Manutacturlng
Co. ; Koppers CO.'8 Metal Product8 Dlvl8lon; National Dust
Collector Corp.: Peabody Enl\'lneerlng Corp. (11); Preclp\-
tall' Pollution Control, Inc. ; Research-Cottrell. Inc.; Claude
D. l'ichnelble Co.; Schutte & Koertlng Co.; Slick Indu8trlal
Co. s Pulverlzlnl\' Machinery Division; The W. W. Sly
l\1anuCacturlnl{ Co.; Sfrout, Waldron & Co.; Steelcratt
Corp.; Torlt Corp.; Tr -Mer Corp.; United McOIlI Corp.'s
DU8t Collector DIvision; HOP Air Correction Dlvl810n (19) .
Western Precipitation's Joy Manutaoturlng Co. (22, 25);
The Wheelabrator Corp; Young MachInery Co.
Meet th~ Author
Gordon D. Sargent Is a proj.
ect en III neeI' 10. ths Nopeo
Chemical Dlv., Diamond
Shamrock Chemical Co., In
Harrison, N.J. The desilln 01
pollutlon-control Installations
has baen psrt 01 his project
enlllnee.lnll experience at
Nopeo, snd prevlaus to loin.
Inll Nopeo, with eelane.e
Flbe... Co. and Hooker Cheml.
cal Corp. He Is s IIraduate 01
M.I.T. with a 8.5. In chemical'
enllineerlnll and is a licensed I
8I1l1lneer In th", St",te 01 New
York. and", mambaI' al
AIChE.
I
I
I
I
I
I
""
JANUARY 27, 1969/CHEMICAL ENGINEERING
-------
Section Three
PARTICLE DEFINITION AND BEHA VIOR
Characteristics of Particulate Matter
.
,
-------
1{,'~rH'int('cI with permj~Hion from IndUl::;trial Water and Wastes Magazine
CHAHA(:TEUISTI(:S OF PAHTICULATE MATTER
G""llrll tr-; 1:I11'IH~r,Ir-;,'F uf paltid,'
~lI'penSIOIIS In ga~e' allllin tbe at-
nlo'pherl' is ,hull n by tl1l' pro1ifera-
tion "I terlllS for ,ncb conditi"ns in
I ('Ct'II\ \ i m('" ("pn'ia 11 y in connection
with air p"llution, In addition to the
;Ig("(lid terIns ,moke, tlnst, fume, fog,
ball', IIli,t. alld clond, we no\\, have
the g('lleric Il'rll1S a(TOS(l\' 'lispensoid,
alld dispersoid, and ,nch nninspired
hI hrids ;IS Sl1I"g alld SlnazC',
!\ c"I1\'('ni('nt and descriptil'l' gen-
nil' tnlll is nel'dl'd in Ihe discussion
,,( 1';1 rt ick 'l1SIWllsi[JlI' ill gases, AITu-
".1 W:I~ "(lil1ed ,hortl)' aft('\' \\'orld
\\',11' I (1(1111 thl' c(lrr('sl'0l1ding (('1'111
11\,<11" ""I l\l'd for ,nsl'ensi(lns IIf 1'111-
J"jda! l':lrtidl's 11\ liql1ids, altl11111gh
II\(' ;lllal"gl i~ PliO! I>ecal1,'(' al'r(l,IIts
!:\l'k tI\(' inl\l'lellt st;d,illt), dlaral'ler-
i,ti.. IIf lI\'dro",ls Nev('\'tl]{'I('ss, till'
(('\'111 ;ll'r(),>;o! dill'S inlply a cUllsider..
;,hk det:'rt'e IIf slal,ilil,V wllicb in gen-
('Iallimits partide ,ize tu tl\(' order of
magnitude of ,.IIt' micron or less,
f lOll ('\'CT, in America usage has sanc-
tiUIIl'd gem'ralizalioll of the n1Paning
to include a1most any dispersion of
particles in air ur other gases, British
nsage fan)rs the descriptive phrase
particlIJate clouds which although
1I1I!\'(' ac,urate is rather cumhersome
I()r gcneral me. Dispersoid has some
;Idvantages as a gencric term inas-
1111\('11 a, it is descriptive and con-
Ilote, a more general type of dis-
!,('r,ioll than ducs thc t('rm aerosol.
Formation and Classification
I >i 'I "'1'''"1'' IIf 1';1 1'1 i,'k~ i II ~~;I~("
,,1'<' diil'lI'lill III .-Ia"if\' 1111 a <,ci('lItifi,'
11;",i, ill 11'1111" o[ tlwi, [1I1I.\;l1ll1'lIlal
l'I"I'I'llil", III 1~"llI'ral, 1':11'11"1" "ill'
,'lid ,,'lllillh ral,' ,III' Iltl' IIIO~,t ,'klra,
II'I'i,tic I'r"!,('1'til" for IlIalll' 1>1III'IIS"S,
""'1' 1''(;IIII!,It-, 1';11'1 il'lt-, 1:11 i-:n Iltall
,iI"'1I1 I O() IlIinoll, (,,) may II(' e~-
['llId('(1 fronl till' category of disl'n-
,iolls 1)('(';111'" they scttle tilO rapidly.
()1I the IItlln halld, partil'ks of till'
I,rdn o[ I V or Ie'iS settle so slowly
;!, to ]", regardcd ; [or most purposes. Despite
1',,,sihlt- advantages of scientific class..
ificat iOIl sclle\11es, the use of popular
Director
by Harry J. White
of Research and Development
Research-Cottrell, Inc.
Bound Broo~, N, J.
dl'snipti\'e tnllis ,ul'h a,; '1IIOkc', dust,
alld IIlists, wllich arc ],ascd essentially
Oil the nll)(1t- uf fOnllatioll, appears to
II(' the nlc'st ,'iatisfactory alld conveni-
ent method of classificatioll. This
nOlllc'lIclaturc is so well established
and understood that it Imdoubtedly
would he impossihle to change.
nllst is fonncil hy the pulveriza-
I iOIl III' \11cchaniClI disintegration of
,olid \11aller into particles of small
,i7e hy sucll processes as grinding,
l'l'u,hing, lasl illg and drilling. Particle
"iII's of dll,tS rallge from a 10wc'r
lilllll uf ahout I I' up tu ahllut lOa or
.2iX) /" Jargn !,:lrtic1cs, altllough
forll]('d, Sl'tlk too fasl to rClnain in
~1I'1"'II,ioll all apprel'iahlc lime, ])I1S1
p:trticks \1sually ar(' irn'glllar i\1
shapc alll!l'arlit-II' siz(' refers 10 sC)Jue
a\'erage dilll('IISioll for allY giveu par-
lid(,. t '01111111111 eX;\1l1ples o[ dnsts are
fly a~h, ruck dusts alld ordinary fluur.
Sa\1d, lIowl'\'er, is ton coarse to be
classed as a d\1st.
Smuke illll'lies ,\ I'ntaill cJegree of
IIptical cJensity amI IS derived fr0111
the burning of urganic materials as
wood, coal, allll tobacco, ::)moke par-
tides an~ very fillc, ranging in sizl~
[mm less than 0,0 I /' up to 1 tJ..
Smoke particles arc spheri,al in
"hape if o[ li'lnid ur tarry composi-
t i, ,n snch a~ t, ,hal'co smoke, and ir-
rt'hular if of solid cUlllpositiolJ such
;\S sout or carhon hlaek. Tkcanse of
I heir vcry fille part ide sizcs, smokes
rt'lIlain ill Slhp('IISiulI for lIlally min-
Ilt(." or I'VI'II holll's, awl 1",lIihit livI'1y
l\r"\\'llian l1",lioll, ('a,ilv Sl'I'1I nlldlT
II II' IIlicl oscol >I',
1'1111/",1 ;11'1' 1'111'1111,01 h\' prO'T~SI";
"wh :IS "tldi\1I;1Iillll, "011011'1";11;011, or
CI"lrI'll,tlllll, gl'III'I'allv :It 1'('laliv('ly
Iligh rl'II'i,natl\1'l's. I'l'l hap>; tlH' CIIIII-
1110111','1 fllllll'S art' dnivcd [rllm thl'
o:>(idalioll of nl<'l:1Ilic vapors or COIII-
1>I)1l1ld" I',g" kad IIxidl' fnilic. Metal-
IlII'hi('al fnllH's of thi'i Iyp(' :lrc g-cller-
ati'd ill great \/II1I11111'S ill various
'i1lH'1t1T opnatilllls, Fnllles rallge in
p;lrtirie size f\'lnll aJloul 0,1 /-' to I 1-'.
I.ike smokes thcy s('ttle vnv slow]y
and I'xhihit strong Hrowlli:ll1motiQl1s.
'\1/,(1,1 or Joy" are [orinI'd hy the
eOllilt-lIs:ttiul1 uf water ur otller vaporo
npoll "nitahk nuclei to gi ve a 511'pen-
SiOI1 II[ sillall liquid droplets, or a\-
tematd)' hy tlie atomization of li-
quids, Particle sizes of natural fogs or
mists Ltsualh' lie hetween ahollt 5
and 100 I', hut very much smaller
pal,tic!es down 10 a fraction of a
lIlicn'n di:lIlleter may be produced by
spe,'ial llIe:II1S. Particles larger than
ahont JOO II, diameter are more pro-
perly classcd as drizzle or rain, Many
of tlH' important properties of aero-
sols which depend on particle size
lIlay 1)(' represented in a convenicnt
:l1Id concis(' ('liart forlll as sho\\ln in
I'ig. 1,
Goneral Properties
1 'art ide 'l"I)('nsiolJs are character-
ized I,y physicaJ and chemical proper-
tit" snch as particle size and strllc-
tun.', rate of settling under gravity,
oplical activity, ability to absorb elec-
tric charge, large ratio of surface
area to volume, chemical catalytic
activity, accelerated chemical reaction
rates, and physiological action. :Many
physical and chemical properties of
materials depend essentially upon the
('xposerl surface area, so that finely
di viderl particle~ frequently exhibit
,marked physical and chemical activ-
ity. Thl' more important types of ac-
celerated a,tivitv encountered with
dispersoids an' 'oxidation and other
clit'mi('al r(';wtions, soluhility, evap-
oratioll, ac]<;urpt ion, catalysis, electro-
static ad,orptiuT1, and physiological
effect. 1 )llSt ("l'losions, for example,
alT c:n1.'I'r! h\' the unstable hurning Or
o',id:1IIIIn (,I' ("(Jm! HI'itihle particles
"roll~~liI ;JI'''III hv Ilwir n>latively large
Sl,(,,'ifi,' ,'i11rfat'(",
('nt.lill tlJ><''i "f catalysts are user! in
11[(' fil1ely dilidct! state either as a
powdl'\' or d11st or else depo'iited on
,,1)111(' ki"d of matrix, The powdered
;J111mi11111ll silicate catalyst used on a
large ,call' since 1942 in the cracking
of petroleum to produce high octane
gasolil1e is an important example.
The l'011tact process for the product-
tio11 \If 'i11]phnric acid provides a much
PA. C. pm. 96.1. 68
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FIG. I. CHART of Dispersoid Properties
older example (1's31 j rot tll.., ~iol' to,; a
iineJy di\'ided catal-'"~t. the ('atah,t in
this case heing platinum in th" i"fm
{,i platinized a,l,est", nr ~.)i1le "thef
platinized material.
Dusts and fumes can adsorb re-
:.!:/."rrs~"c...S.0.AII- ~~~!~- H, q, ~ 1\.0 cq, co, 1\.0 ~ 0, I\.
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i:tti \"('1.\ large quantities of gas on
t!Jei r surfaces. .\ coUected mass of
'\1ch particles assumes some of the
properties oi liquids and gases. The
mass splaslles like a liquid when car-
ried in a pail, ripples are formed when
a stone is dropped into a tank of
~uch dust or fume, and these "liquid"
dusts can be poured or pumped
through a pipe. The mass of dust or
fume can be compressed like a gas.
Dispersoids can also take up relative-
Iy large electrical charges. and as a
result exhibit marked electrical ac-
tivity such as building up high poten-
tials on insulated electrodes immersed
in them. The effectiveness of electri-
cal precipitators is fundamentally due
...
<:>
-------
fiO
to the abihty of dispnsoids to adsorh
large anJOunts of electrical charg('.
Olle of the most important charac-
t('ristics of particle clouds is their
degree of dispersion or finelless which
is brst ('x pressed hI' llH' specific sur-
face, defined as the total exposed
surface area per unit mass of the
dispersed suhstance. The conventional
unit for specific surface is square
centimeters per gram, In order to
visualize the slgnificancc of specific
surface, consider a 1 cm culJl' of ma-
terial of unit densitv and suppose
that it is suhdivided ';nto cubes "a"
CI11 on ,l side. Then the ratio of the
total surface area of the smaller cuhes
to that of the initial cube is
Total surface of s111all cubes
~.-_._---~-
Surface ;II'\'a of I cm cuhe
x 6a2 1
a~ x () a
Thus tIlt' suhdivided euhes have a
total surface area of I/a tinlf's that
of the initial 1 C111 euhe. If, for ex-
;ullplf', the s111all ,'uhes are 1 IL
I =-:- tO~CUI) "u a side, tllf're will he
101~ cuhf's and the total surface area
will 1)(' inlTeased hI' a factor of 104
or to ()O,nO() sq cm ~vhich is the value
"f the specific surface in this iustance.
Vallws of specific surface for typi-
cal oispn.soids are ,Iisteo in Tahle I.
Specific surfaces of particulates are
seen to cov('r a vcr\, wiele ran~e of
values, from ahout 50 sq cm/gram
for sand to over 1,000,000 Sf! c111/gram
for fine carho!1 hlack. However. most
oispersoios have specific surfaces in
the ran~e of 1000 to 10,000 sq cm/
gram, the s111all \'all1es associated with
coarse ousts and the hrge values
with fine smokes and fU111es. Acti-
vateo rharcoal is reprr<;rntativr of a
r!as<; of materials sppri:1llv processed
t(1 form intricatr l'0rol1s intrrl1al
~tn1('tl1r('s characterizpd hI' (.,.;1 rrlllt'lv
largr sprcific sllrfac('s. Thcs(' suh-
stal1<'('S, l1sed for dwmical alld 1>llv~i-
cal ads"rptiol1 and for c1H'ulical ;IT1(1
1'11\'~ic.rI ;1<1.<,orl't iOl1 al1d for "!H'll1i('al
cat;rI\,si.s, ;11'(' of ;lIkr<'sl h('I'(' as a
IlIatkT of cOlllparison.
TII(" a('('('ln;lkd ,'!I('lui('al alld I'llv-
sical r('a,.tioll lat('s as:.ocialcd with
Ihe n'lati\TI\' I:1rg(' Sl,,'cific sl1rfaces
of fill!' partirlcs an' l1tilizl'd ill IllallV
practical \\'a\'s- Comnlou ('xamples
are thl' atomization of fuel oil and
the pl1lverization of coal to provide
rapio combust iou in furnaces. Granu-
lar forms of sugar and salt are used
to illcreasp solubility rate.
An unwanted effect is the explo-
T.bl. I
-- - ~.-- --------
Ollpenold
Man-Median
Dlam.ter
Specific Surface
N~wly.~arm"d
1 o[,.C(O Smoko 0.61'-
Fly A..h, r "'" S
Fly Aoh, CUM'O 25
Coment Kiln DU51 13
Ol.,t Furnoce,
After Dry
Du,t Cotcher A
Fine Corban BI.ck 0.03
Activoted Choreaol
FinH Sand 5001'-
100,000 em2/qrom
6.000
1,700
2,400
4.000
I, I 00.000
8.000 000
50
-- ------"-----
. -----
sion of dusts which occurs undn
ct:'rtaill conditions with organic dusts
such as flour, resins, sugar, amI some
metals. Minimum concentrations nec-
essarv to produce t:'xplosive mixtures
in ai~ vary hetween about 4 and 40
grains/cl1 ft, based on lahoratorv
trsts. Ignition may he caused acci-
dentally hy many' agents including
stat ir: sparks, grinding sparks, open
flamrs, overheated heariugs. and other
hot sl1rfaces. Ignition temperatures of
many combustible dusts arc snrpris-
ingly low. For example, sl1lphur
dl1sts may iJ!nite at a tempera! I1re as
low as 2R()°C., tohacco at 250°C.
and cocoa at 240°(:. The design of
indl1st rial gas handling an(1 cleaning
eqnipment in sOlue caSt'S reql1ires pro-
visions for preventing or minimizing
the effects of dust explosions.
Stability
1'al.t icle suspensions inherently are
11l1stahle and tend to disappear with
time. The principal forces which
ca11Se the instability are:
I. C;ravitv settlinq-particles larger
than ;hout JOC)!' diameter settle
in air at the rate of one foot per
~econd (fps) or more ami may
he lost in a short time.
2. /!r{J7('II;(/1i 1I1ol;(ln---fil1(' part icles
of sl1h-milTol1 size tend to 1'0-
;lgl1];I!,' quite rapidly owing to
tlll'ir l;v('lv Ihownian mo!ions.
Thi... gre;"lly rednces particle
('olHTnlration, iUlTeas('s ;w('rage
particle sizt., and in tinw nlay
karl to sdtlilll: of tIle partict.-s
hy I:ravitl'.
3. /-:7'(//'(11'(//;(111 Ilnportant [or
partieks whicll have relatively
high vapor pn'ssuf<'S at amhient
gas temperature conditions. For
cxample, natural fogs wil1 dis-
appear hy evaporation when at-
mospheric temperature rises.
4. Thrr111a! qradirnts-particles
exposed to thennal gradients
tcnd to he deposited on adjacent
cool surfaces as, for eXersoids to disappear,
either gradnally or rapidly, depending
011 conditions. In relatively calm at-
mosplll'res, particle size of the sus-
pended matter is in the range of 0.1
to I I" as larger particles settle out
amI smaller ones coalesce. Tempera-
ture inversions, with little or no
wind, trap smoke and other fine
particles and produce the hazy,
smoky atmospheres characteristic of
urban smog;s. Highly windy, turhu-
lent conditions, on the other hand,
cau~e ('Veil relatively large particles
to r(,l11ain in suspension and abo wil1
r('su~(>cnd particles frolll exposed
ground surfaces. Extreme examples
of this condition are the dust storms
which Occur in the southwest U. S.
Tn industrial gasps. where gas velo-
cities in flues and ducts ar<: of the
order of 2.1 to ] 00 fps and the flow
is highlv turhulent, suspended parti-
cles a~ -large as several hundred mi-
crons if present are held in suspensioll
ano carried with the g;ases, These
larg;e particles commonly are a source
of 111nch nuisance as they tend to
settle very rapidly in ref!iOlls of
lower gas velocity or shielded !!as
flow zones and may therehy produce
dust buildups several feet d~ep, which
tend to block gas flow and in SO'11e
cases to forlll harel, concrete-like de-
posits.
Particle Size and Structure
I 'artiek shap('s of dispersoids in-
dude a myriad of types front siluple
spIH'r('S Ir> cOinplex stars and ehain-
lik(' aggregat<"i. Fogs, mists, awl some
sUJO!.('S an' e()Jllpo~ed of spl]('rjral
liquid or tarry ,Iroplcls. Many fly ash
p;lrtirks. producrd in tile comhustion
of pnlverized roal, are hollow spheres
or c('ntispheres freql1ently with much
smaller or satel1ite particles attached
to their surfaces. Dust particles usual-
ly are irregular in shape as the result
of 111ultiple fractures which occur in
crltshing or grindin~. Many metallur-
-------
glcal fumes have a star-like or plate-
like shape. while others are needle-
hke and tend to form agglonwrafcd
chains.
l'artick size may he specified un-
iquely by a sinJ;le parameter only
for spheres. cuhes and other simple
geometrical shapes. For all other
particles some kind of average di-
mension or equivalent diameter mU'it
he used. For exanlple. with irreJ;tllar-
shape dust particles. the average (Ii-
mension along three mutnally per-
pendicular axes Ilia\' 1)(' n..,ed, or tilt'
dian1l'tn of the 'ipl1('re having Ihe
sanl!' volnme or the 'i;lIlIC surface an'a
as III(' irregnlar particil' Inay he cho-
sen. ."no(her approa,'h is to tt~e SOIII!'
ph\''iical propntv such a... the ",('lIling
ral(' of the parlicle in a gl\'en flnid
to specif\' an e'lul\'ail'nt ,han1l'((,[. [n
this latter cast' wh,'n' the Pllrti.-les
settil', at leasl appwximatdv, in ae-
cordance with ~tokes' I.aw. the eqniv-
alent dianl('tcr is gent'rall\' designated
as the Stokes' diameter.
It is evident that partieii' ...ize for
irregular-shape particles will dep('lld
on the method used for det<'rmining
the a vnage dimension or equivalent
dianll'ter. and that. in general. no two
method~ will agree. For this rea.son,
it is essential that particle size re-
sults he specified in terms of the
method used. To illustrate the point.
('onsid('r a cuhical particl(' one Inirron
on the side. Then tll(' following are
illustqti\'e of the diffnenn's in mag-
nitude:
i\ verag(' diamdn hased on three
dimellSions I".
f)ian1l'ter of e'lnivalent sphere of
sall1l' vol lime :. 1.24 ".
I )iam!'ter of e'luival('lIt sphne of
same surface area 0',' 1.3R ".
(>hvioll'ily nlore irn'gular shape
particles have ,t:reall'r variations in
eqlli\'alent diam('tns. For extremely
irregular particles sllch as plates.
rods. or stars I he concept of equiva-
lent diameter is of very limited usc-
fulness and SOI11(' otl1('r measure such
as specific surface or settling rate
has greater significancc for most pur-
poses. For example, ill IIlany gas
cleanillg proccsses the setlling vclo-
cit\' has din.(.t physical nll'aning !'s'
sentiall\' ind<'J)('ndt'nt of particle sl mc-
t u rl' and would Iw pref"r!'('d over
1''lIi\'alt'lil diallle«or.
Particle Size Determination
From the preceding discussion it
is evident that determination of par-
ticle size cannot be uniquc except for
the special case of spherical particles.
For all other cases. the results will de-
pend on the experimental method
used. Therefore, in general. the meth-
od chosen should he selected with due
regard for the end use of the results.
As an example, if the hiding power of
a paint pigment is the quantity of in-
terest, direct measurement of cross-
sectional an~a would he preferred. and
th" results could Ihen he giv{'n in
Innl'i of nl'livaknt diallwtcr hased
on lilt' ohscuriug area. [n electrical
pn'Cipitatiou Ollt' is interested in the
migralion velocity of a particle in an
eil'c(ric fidd, and 111<' Stokes' dian]('tn
or s"ttling velocily WOlild he the nlost
Iisdui.
Virtuallv all dispnsoids. whether
natural or man-made. Ilave a range
of part ielI' sizes and shap('s. T .iquid or
tarry dispt'l'soids such a's fogs or
tohacco smoke are spherical hy nature
hut usually vary in diameter over a
wide range. Soli c1assifit'd into the following
g('II<'ral categories:
I. Sit'11t' analvsis usdul for re-
Ia t i vc\ y coarse pa rt iel(.s aboY('
44 /', corrcsponding to a 325
nwsh srreell.
2. JI.fir/'{/sr()/,ir /ll1alvsis-the max-
imullt resolving pow{'r of optical
microscopes permits determina-
tion of part icles down to about
0.5 ,.... while the much greater
resolntion of electron micro-
scopes extends this lower limit
to about G,al "..
3. S,.dilnentalion analysi,r-basecl
On measurement of settling rate
of particles in fluids. Gives set-
tling velocities directly, and
equivalent diameters inclirectly,
hased Oil knowli or assul11('c!
laws of tll(' flow resistance or
51
drag of the particles. Stokes
diameter is determined by this
method which is useful for par-
ticles in range of about 0.5 to
SO p..
4. Elutriation analysis-based on
separation of particles in verti-
cally rising fluids whereby fine
particles above a size cutoff
point are carried upward with
the rising fluid and coarser par-
ticles below the cutoff point fall
to the bottom of the elutriation
chamber. In practice. a series
of graded elutriation chal11hers
may be lIsed to separate particles
into a series of size classes.
S. ('entrifl/{/ul anlIlvsis---Similar ill
principle to sedimcntation. but
ns{'s centrifuRal forces which in
the hest ultra-centrifuges may be
as high as one million times
gravity. This greatly extt'nds
th(' lower particle size limit
down to giant molecules Or to
about 0.01 p..
6. Impaction methods-particles
are deposited on a plate liurface
by impaction from an air jet.
A series of graded impactors,
the so-called cascade impactor,
may he used to separate particle..
into size classes.
7. Photometric methods-utilize
light scattering or absorption,
hoth of which depend on parti-
cle size. Photometric methods
are most useful for fine particles
below a few microns in size.
I -ower 'Iimit by the best techni-
ques is ahout 0.03 p. for mono-
disperse or uniform size particle
dispersions.
R Misccllaneou..r methods-include
gas adsorption methods, air per-
meahility, X-ray diffraction.
Detailed disscussions of these meth-
ods are to be found in many literature
references in which the apparatus.
techniques, applications. and results
are thoroughly covered. It is safe to
state that in practice there are liter-
ally hundreds of methods in use, all
hased on variation or combinations of
the basic methocls described abovt:.
Each variation has its own actual or
fancied aclvantaRes which depend on
the type of dispersoicl to be studied
on the ('nd use of the particle siz~
data, 011 the accuracy aud time re-
'lIin'I11f'llts, and 011 th(' preferences
-------
ii2
of the investigator. It is apparent that
110 tlnivl'rsal I1lethod or apparatus for
p;\rticll' sil" dl't(,rIninatiou is possible
('v('n ill 1'1 il1ripk. I;or use ill rOlUH'('-
liol1 11";111 1-:,1' cleaning al'plicalioll,
IIH' '!'dIIIH'lllallol1 al1d ('liltt i:llioll
1ll<,th"ds ha\'I' VI'!'V ddiuih' ad\'all-
!;Ii:'" III'('all'" till'\' giv(' l'I'slills in
I<'nll.' of .s<'l1lil11-: \'('Ioritv or Stnkl's'
dial1l<'ln. ()II III<' olher hand, thl'se
Il1l'IIIods usu:dl\' 1I!'IT'Sitate rl',dis-
IIlTSiol1 of collerll'd particle salllpies
1I"1,;ch 111:1\ II(' diffinllt, while al1v
:1!~glol1l1'r:II(" I'n's('llt in till' origillal
di~I)('1 ",id (';\llIlnt Iw 11'1'1'<((1\1('('.1 ill
tlil' p:lr(i,'I(, Sill' <''Uipllll'lIt. .'\11(1(111'1'
1'1"1,1111'111 ,'Olllll'l'Il'd \\'ith si7.ing (If ill-
.11"( r;:d di'pnsoids is that of proem-
ill;": rq'n''!'nlalivl' samples frolll thl'
iil'ld 1>('C;IU~I' oi th!' very largc gas
fl,,\\.s all' \ \'a rial,k cOllditions which
CI,:ILlc!ni/(' 11los1 il1dllstrial gas cleall-
]tl,~ ....itU:Lti()1b.
Particle Size Statistics
II I' of ;111('\('" 10 11111,' IIIal Illall\'
"f till' 1':1,.1"'1,' "I" di,I,.t!lIltiolis ,'II
,'''uIIl<-n.,1 ill 11.11111'" alld ill tl'chl1,>lo.~\'
IIIWI' 1:11111'1 '11111'k SI:lli,li,,:t! d"Iri
11\ It iPl1 1:1 \\ ..., 1'1 Ie t ;;11 h.,j ()! I (If ~,~ I
,',dkd 11111111,d dl,IIII'lIlillll 1;11\", I\"hi('h
i, :1]II'I,,',d>l,' III dl,lrillllll(111 of lal1dlllll
,'n,'" III ),11\ .,ical l11<'a'lIn'llll'II" :111<1
"I", 1(1 till' di,lrillillilill (If 1I1IIkcul",.
\'1'111,'11 iI" ill 111<' "illt'l i" tlll'III'\' (If
t.:"".,. i, !:nl'h' f(lulld III :1]'I'I\' I" thl'
,i/" oI"t,.illiltilll1 (If displ',,"i,k III
~"lln;d. IIII' dl,(rilluli(l11 i., ''','Wl''1.
1 )r;Ii1,l'!' flllll,,1 that f(lr 111:\11\ disl'l'r-
",id, IIII' ,h'l\ 11("S could lit' eli111;11-
:II,'d 1,\ 1,J"llill~ thl' logaritl1\l1 "f 1''11'-
li,.k "I". :\1:,111 il1dll,tri:l) di.o;pnsn;ds
1,,11,," thi, IlIg-l1rnhaLilll\' partid,'
,ill' di.,IIII'lItl"l1 law rathn \\",11, alld
Ihl' 1"!:'I'r<,J,:tl,iJitl' 1",'hill'IIll' "f I,I,,!
1111t.: l"llli, I,. '1/,' d;II;1 " \I'i,kh' IIsl'd
Resistive Forces on Particles
dnd Settling Velocities
[lit' 111111H111 (11 ;111\ 111:1!('rI.i! 1111]1'\ t
1111 ""!' I; I II I 11,1 11 1t.,J i 11111 i" ""1,1,.,1
I, I II", 1 11",1111111 II i I 11 :t I "I It. II'III,.I!.
II! ~'(" 1('1 ;11, (kJH'111!', r If I till' ',I 1(' ;11]1 I
,11.11'" "I lilt' III,i,', I. tl1l' 1,.1.111\'" 1,1"
'III ,01 111" "I",.,.t .111,1 11,,1'; :111<1 1111'
<1"11',11 I' :" It 1 1'1 '.It ".11 I , d II" II"i,J 1111'
, ,I' ,. "I "I >1"'1 1t.1I I"" lit", i" 1111' '.1111
1,1",1 1" ,II'" II'.' 111"""'11. ,till' till' \'(.
<"1111, :11 ," 'IJJI.!\'irl,~~ 111 (II di'r (II 111.11'lli-
t IHI" I" 11"1 ".l:III:t, ,JI;'! It'd I" "Ii,., 11'111,,11
:tl 1<-:1'1 rr('1"(' A : -. Jlu'an-fre('-p;]lh of gas
n101ecliks -.= 1 O'~ cm for
air at NTP
A :..~ constant := O.Sf)
Thc Cunnillg-ham correction of
Stokes' formula applies to the case
for which the partiC'le is small enough
to tend to slip between the gas mole-
C\des, This occnrs when the particle
.I iarncter ecoilles c()1l1parable to the
11l('an-frec-path of the molecules of
IIII' gas. For air at NTf', the mean-
fn'e-path "'Illals about IO'''cm, and
IlI'l1ce flirt his case the Cunningham
,"IIT('c! i, In !)('CI}11lCS appreciable for
parti('ll's Slllaller than about IL di-
;lInel,.,..
\[,'wlon's
'"
..
~ .
10'
tar--1'" --T&---i()' ..
REYNOLDS NUMBER -
"'~~~"~w
. I~:l - - 10'
R
I.
FIG. 2 PLOT OF the result of experi-
monts studying the relation of CD to
R
a Sphl'lT 1110vi11g throl1gh a fillid. Each
IIf th,'~(' forll1l1las has a lil1\iteJ range
IIf applicability, hilt each within its
prllpl'l' rallge gives results accurate
('I\I'llgh for IIlO.,t purposes. No at-
1('l1lpt ;S Il1ade ill this article to derivc
IIII' fllrlllllias /II' to discuss the general
111l'0rv. Illstcad, thl'l'e i~ givclJ a SUIll-
111:11'\,'IIf the fOrt\l1i1as al1d th('ir ranges
III :I\'plicahilil\', t"gelhn wilh the ex-
1"'1 illll'II(:t! Cll1'\'(' fill' the drag C/l-
('lli, i"1I1 III spl\l'II'.s h:lsl'd 011 Rey-
llilid' ~ Illlllll)('r.
."llIk\< 1,;111
I)
II rr 11 aw
II III' Il'
drag "I' resislive force
(11\ pari i,,11'
a p:lrlic!c- radius
'I vi.sco~;ty IIf thl' gas
\I' partlClc vel')('lty
Thi, fOrllllt!a \l'as fir,t derived IJY C
SI,",l's (l:-;-W) al1d i~ \':did for s111aJI
particles and low velocitll's such that
III(' 'IIrrotllJding 11wdil11n is Ilot (lis-
turl)('d I,\, Ihe 1l111till11 /If the particle,
a 1\ pI' nf 1111)tiC1l1 Of«'11 n'ferrl'd to as
"neepil1,l; 11lotiol1" Thl' \lpp('r parli-
cll' siZt. lil1\it for which Stllkes' for-
llIlIla is rea~IIualJlv valid llndn 111t'
I"lIlldil inlls uSII:t!I\' "I1<'/llIlll1'red il1
,.1(.,., ri,'al 1'1'l,,'il,iLlt lOll " al'l Jr, IX\"
111:11 <.h. .In In ,II) I',
II ,hollid )", I,,"ed that thl' d'";I.t:
I) III! ,I part1l'1(' 1I1(1\'iI1.~ ;lC~'rl!.dill~ III
',llIld",' I:II\' io.; dll'('elh, l'lol'"rlillll:d
III 111/' I i"'IISII I' 'I IIf 111<' fillid, III tl\l'
1',111 i,'I,' r;ldlll'. :1, :11111 III : I", 1',11 I i,'J,-
",.111' ill' II IIII!;- II1Ib'p"lId"lIt (d tll"
d, 1I'.ill' I' IIf 1111' fillid. '1'111': 1111'''11' 111:11
II I. 111,1"111'11,1,'111 ,i! J:.;~' 1'1'l",sllr~
. ""1" ;11 1'('1 I' 1111\ ,ll1d 1"'1'\' hil'.11
III ''','.111 ''''. ',to 111:11 ,( 1';11! iell- ,,'111;11,.,
(1IIdl'l 1'.""'<11',1111 ('''1111\>1", \l'ill sell I"
;d 1111' ',,:IIJlt' r;t!t' 11\"'1" :l wid(. range
(II t!;I'"- lItT"""'lIl{''-"
('h:IIJ.~III\: Ihl' g;" 1"II'1Jl'\';tlIITT, 011
tll(' 011\('\ hand, eh;ln,l;I" II\(' \'iscllo.;it\,
I)
r .;lW
]) "''' 0.72 I)a"w",
\\'111'1'('
Ii ,= density of fluid.
!\; l'\\'tlill '0.; formula applies to ]arge
l'ar1icks traveling at high v('locities.
! ;nder 111('''' ('(Jnditi(J!1s the l110ving
l'artic1e s('ls II]! eddies in the fluid
alld t11(' n'c,ulting drag I",d ;1, a fllllc!ion of Ih('
111111
-------
y = killematic viscosity of the
fluid = '/p
'1 ::- yi~,'o~ity of the fluiJ
" c-: dl'll~ity of the iluid
R i, IIOIl-dilll"llsiollal ill the Sl'lI,C
that it,; v:tlu!' is illdl'pClldcllt of thc
~~ ,tell I oi ullit,; used, Surh 11011-
dillll'IISi"Il;,1 'illallliti('s have a wide
uS!' ill pll\'siral sl'i"lll'(' alld l'llg;i-
II<'nill,l:, TI1I' 1IIIIIIhn R wa, first
IIsl'd ",' ( U" 'III" h:I'.I'IlIIld, (I ~KI) ill
r'\lIIII','li"ll wilh hi, I'xpl'riml'lIt, 011
Ihl' il",,' "i "';lllT through pipe" The
,igllifi..all(,(' (Ii I, is that all g"OIlIl'lri-
,'ally ,illlilar '-"SI"IIIS whirh have thl'
,aliI<' yahll' oi I{ \\';1\ also have Illl'
,':LIlIl' fl"w ..lIlIditil:I1:;, the 1'01'1'1"1'"1111-
"III',. 1"';lIg 'illallt:i'lti\'e, Thi, 1"'l'IlIil"
i',r 1':'\ all '1 II,., "Il' plllllillg oi all l':'\-
P('l';lIll'lIt:,1 n"II!h i,'r thl' drag; 1'0-
effirirllt of 'pl,,'\'(', Oil olle 1'0111111011
..lIrve. rq~ardl,',,; of the dialll('ter of
till' 'ph('l",' "1 tl1(' ki!I[1 of fluid used,
'I'll[' dr:lg ('[),efii,'irllt, c... is defill[.d
""
(.'<1
\)
( !.") "IVeS
wlll'n'
:~ ;1 SI,t:llifit':l1lt arc;! ass(u'ialt'c1
"ith III<' III'i'TI. Ih,' 1'I"",-,;(','lioll;tI
;11'1':1 (,,' I ill t Ill' ..a", "i .'I 'I'h('l'l')
'1'111' "I;I~: ,'II ..fii,'i"llt i,.'I fl1llt'tioll 0111\,
111' 1,1" 11111"', 111111111('1', i,('" (',I f( 1\ ;,
'I'l,;, I 1'1 a I i"II, ill ,g"lIlTa!. Il:Is 1" I,,'
"l'Il'IllIil:,,, For ~
'l,h['1'(', thl' value of I,'" is giv['11 IIY
F. :-:: (4/3 )1I'a:l"l.l:,
1\'11t'\'I' "1 d('II,silY of ,phere,
I;"rllllila :dl<'\'(' \\'1"'11 cOIllI,ined with
:1111' "11(' oi I hI' dl :I,g f"l'IlIllla,. will
,I'i\',' lilt' sdllillg Vl,I,l('il v for tilt' ('or-
\("1" 'lidill,: ;q'pr0l'riat,. COlldit ion a,'
10 I';lrticle size,
Electric Properties
TIlt' 11'0'1 illll'orlallt ,'1,'('1 rica I prop'
"rtl<'s of susll('\IIh-tl p:Lrtiek, are
Ihl'ir ,'I"ctrir ('harge alld cOllductivity,
!\ear1\' all I'ilrlicl('s. whether natur~u
or IIlall-lllad(" arl' charged to a certain
d('grl'e, l{aill drops an' of tell appreci-
;,111.1' charg('d, alld the highly charged
cloud, accompauvillg lightning storms
;'1'1' evidellce of a natural charging
1'1'11('1'';'; '1'11(' sO-l'allt.d "precipitation
sIal i,," or ~l'VLT(' radio interference
(" I'lTi('lIl,,'d I Ivai rl'lanes ill rain or
',1101\' storlll, is dllc 10 thc rJ('ctrical
el1;lr;:ill,L: \If rain or SIlOIV drop, strik-
illg- or l('a\'illg till' pl:lIll''s surfa('e,
TIlt' Sallll' 1\'1'(' or ,I at i,' illtl'l'fl'rf'llt'('
i,s al,.o ('Ilt olilltl'n'd h~' airpl:III('S flyill,g
I"rollgh dllsl ,tOI'lIlS, :\ gn.:tt (Ito;" 'If
"I'''':tr.." IVork w;\S t'o,,,h1l'1('d duril1g;
till' \("'1'111 war 1111 )11'(,,'ipit;ttioll static,
:llId I1II1<'h il1l)H'rt;fllt illfol'lll:ttioll wa,
di';""I'('\('d Oil W:II',S alld III,';I\IS III'
\('''lIIilll~ 1"(' flvilli: "a/:lI.]" dll(' 10
JI\(',ipil:t1 i"l1 ,tati,',
Natural Electric Charges
on Particles
"rart i..al1\' all na t lira! or indllstrial
dllsts an~ elcctricalh, rharged to an
53,
appreciable uegree, The fractions of
J>o,itively and negatively charged dust
prescnt are generally equal. ,0 that
any givell dust suspension is as a
whole.: electrically neutral. Fumes or
,lIIok,'s are al,o u,ually charg-ed. al-
thollgh to a lower degree thall IIlOst
dll,t, '.reshly formed mist, or fogs
:J 1'(' fOil 11 al :lI11011 11 t, T"i, i, the explan"tion
i"r tll['SI'('alied "frictiol1all""argil1g"
"i hodi['s, althollg;h it is clear that
iril'fi'"1 as ~lI('11 110t eliteI' ;ntn l"on-
"id(Tati(ln,
111 t 11(' ('",,(' of fl1ll1e, ;1I1r1 slllokes,
I h,',,(, is 11" t'llrr('sl)(IIlrlinJ{ charging
111('('I1;'l1isJ1I pn~~l'IIt. Th.. particles are
lorllH'd hy cond{,l1satioll from the
vapor pllase, anI! Ihe onlv source of
i'lilS \\o'ollld lie Ihat due to 'flallles used
ior prodllring the vapor. Ilel1l'e for
vapors fOrJIled at high temperatures
i 11 flal1l<', tht'!'t' would he a charging
('ffect, althuugh lIot ordinarily a very
dfecti\'e one except for very lugh
telllperature flallles and for electric
arc" Y n the case of mists or fogs
whi!'!l are f01'l1wd hy condensatiol1
frolll the vapor pha,1' ~t relative'" low
II'nlpcratuf'{'s, tllcre is 110 iOIl s~urcc
1'J'('''('lIt alld ,1I<.:h di"pl:rsoiJ, are
IIH'rl'illl'l' initiall,v ullchar~'ed,
'l'al"" 2 ,g-i\'l's a '1lIllmarv of the
lIatllrall'h:lrg", fOUl1d on so\;le repre-
"'lIlati\'" cli'p(T,oid" Th{'se values
\\'1'\'(' dl'I<'I'II
-------
!i4
x 10" [or dl"!.' alld ;tI"'tlt 10" ,"II
P'T gr;tlll fill' filIII<" ;tlld ,'1110\.;""
TlwSI' \,;1111<" all' Ili~:h ('II<>lIg}1 tll
,'all'" III<' ,'hargt'd dl'I"'1 ,,1111, III (.,
hil1l1 "I I illig ('1('1'1 "II<'al illil df,','h. Th,'
';1',111" IIII<'II II<>li,'('d 1'1'11111 11I,1I1a1('d
ohjlT" Ilia,,'" ill 1111' 111111,'\ gas ,11'1';1111
frolll pr'Til'I(;IIIII, ,11'(' ('I'ldl'I1<,(, III' a
Iligh (kgl'l'I' III' ,'hTlrifl";llillll.
Electrical Conductivity
1';lrli('I(. clllldllcti\'itl' 1'\'11" ,( 1';I,ir
1,>1(' ill ('kctn",I:11 i,' 111 ,},','s,,', \I'hi('h
il\\'o!,,' Ih,' ('o!krti"lI. d(,pll,ition, or.
1,'II!;lli"n, or '<'1':11':111111\ of I'artinl-
1.11,'" In tll" ekrtril,:tI I'r<,('il'ilalion
111<'1111,<1 IIII' ,C::1' ,'ll'anillg 11ll' 1':lrti('k,
IIltl'! h,I\'(' :11 k:ht ;t tr;\(',' ,'ol1lkding ek('..
In,,'k 'Id:t",. illlp!'de tIll' 1111\1' IIf till'
('oron;1 1<111', Thi, ,'olldll iOIl 1I'llally
is 111:llIil""I,'d 1,\ ,',('('s,il'I' sl';lrking
alld hI' I't'dl\(",tl pr('cil'itatllr CIl1TI'1i1
and \'1I!tag(' \\'lli('h in IIII'll 1':111'" ,I
lowerll1g ill pl'('('il'il:111I1 I'nf'lI'Il\:lIl('('.
Both tlll','rl' and 1"q",ri('I\I'(' il1di('atl'
that thl' nitl(',LI or IlIilllllllll1l \':1I11l'
of p:trtick c"ndllrli\'it\' lor nOrllial
pf('('il'il;tt(lr IHTf"rllI;tll(,(, i, al"'1I1
n,s " 101(1 ill 1'1'1"" IIhl11 CI1I. or as
11IOIT 1'I!\nn1tllll\' e'pl't'ssl'd. ,\ Iliaxi-
11111111 f(',i,ti\'it;, of :lhont 2 , 10"1
ohll1-rlll, I 'a rt iell' resi,ti vities grf'atn
than this \'ahll' lead to redllred pn.cip-
itator dfirienl'\'.
A!th01lgh many dusts and fnll1es
arc Clll11pos1:'d (If nH'tallir oxirles, sili-
catt's, and the like, \\'hirh in the purf'
stale are g(l(lrl insulators, there usual-
ly arc presellt in the gas and particles
suffirient moisture and illlpurities
'lirh as sulphat"s alld chlorides to
prO\'idl' ad('qllate COllducti\'it y for
ell'clrir:LI prl'ci I'itat iOIl purpos('s. For
1"llIp
~ 10.0
Vi
w
II:: 10'
10. 0
100 200 300 400
TEMPERATuRE. . c-
FIG. 3. RESISTIVITY TEMPERATURE
gra ph for fly ash.
T.ble 2
Natural Charges on Some
Representative Dispersoids
ChMQ8 Distribution Specific Chdrqe
Dispersoid POI. Neq Nou1roJl Positive NOQative
(nu) (..u)
4'1';" 1.'1,10'12.1 x 104
fly A',h ]1";. n';:,
('YP~ulrl
I )u'.1
CnfJfJUI
~H1IPlllJ!
[JlJst
I "lid
rumn 2~)
LnIH)(l'II(HY
0,1
44
oil (, 1,6 1,6
~J(J 10 O,L 0.4
75 50 01103 O,OOJ
40
f Iln\<
o
100
o
(I
o
It'1l'llt'ratuIT, !WCOIII(' ,ufficil'lItly cou-
ducti\'l' to illsurl' gll"d precipitator
adinu. ;\t 10Wl'1' tel11p1'l'atures ill tIlt'
rallg(' nf 2S0 to 4S0° F il is soml'till1l'S
Ill'CI',,'iarv to cOllditiou tit" ,c;ases ahl'ad
of tIll' 'prl'cipitatnr hy addit ion of
IIIt.isturl' or (,("I't;liu Cht'llli('al l'oudi-
tlolliug ag(,lIts in ordn to luwn par-
tick j'('"i,li\'itv !)('lolI' thl' t'i'itiral valt\('
of 2 x lOll) ...ltlll-CIlI.
The dkct 01 c!H'mical "Ulldili"llillg
:1~"llls Sl"'I11S tl; 1)(' to hilld uI"ist1llT
to tltl' particles. 1.'111' ,'xall1pk. ill flv
:ish ;1 thill film of sulphat(' I1sllally i,
pn's('ut Oil the parti('l<-s alld thi, ill
tl1rll greatly ill('JTas('s the 1110i~t111T
adsorhl'd Oil till' r:lrti"k" In this
illstallce thl' sull~hak is pn'sl'llt l1<1tl1r-
aliI' ill the f111f' gas as a resl1l1 of the
hI11'1lill,l; of the sulphur ill t he coal. so
that f11' ash ill 1110st cases has a(k-
quate ;'onductivity for good electrical
precipitation, Other chemical cOlldi-
t iOllillg agents which may he l11en-
tionrd art'. ammollia gas used for
conditioning the pow(kred-catalyst
dust from the petrnlel11J\ cracking
process, :llld chlorid('s for the condi-
tioning- nf rntain "xide dusts anrl
fumes,
J\ t \'pical \'('"sl i vi tl'.tel11pf'rat \11'('
graph for fit :I.,h la\"'II ill tlw lah"ra-
Inr\' in atlllt,,'pllt'ri.. air ('II vi rOllil It'l 11
is ,hO\\'11 ill Fig, .\. 1\.1 ax i I11U III I'<'sis.
lil'it\' "c..l1I" ;It ;11"'111 12S"(' 1\,,111\\
Ihi, t"llIl'l'I';11111 (' lilt' 'II'f:I\,(' I,',i,ti\
II\' "f lilt' l'arti..I,'"
>-.
If)
If)
~ 1010
10
20
'c
WflH R VAPOR BY VOLUMf '
...
FIG, 4. EFFECT OF WATER VAPOR
on resistivity of clay dust.
-------
fllr (-"l1oids. Ull"velwau alld AIH111hnt
h;l\"(, als" lI1ad(' ('xlellsiv(' ~tlldi,', of
I~avkigh's fUrlllula ;,lId glv,' a IIIOdl-
fi,'at illll claillwd I" he 111111" gelln:II,
1-'<11 ,I n"'('lIt discllssi"l1 "f tll<' ,',(';11[('1'-
Ilig IIf lighl )\ filll' l'arl;..I,'s, rdn-
('11<'(' i~ 111 a II" tll ,l paper 1,\ I.a Mn,
:\11 of the", r('slIlts IIUY II(' ~\IIII-
lI\ari/.('d as Inllm\',: TIi,' sl'atlnillg "f
light hy a sillgk particle d('I)('lllls up.
Oil the size, shape. rdral'liv(' illdex
alld. for largn particks, "II the color
IIf tile particle. I~aykigh's law of
scattering is valid for ,llIal1 particles
of sIze up to allout 0.1 llil' wavl'kngth
of light, and prl'dirts that tlie scat-
t('red liglit i, propnrti'liial t" the
si"th pown "f tIll' particle di:lI1H'ter
alld invnsl'ly p1'l>portional to tli('
f"!lrth power of the wavl'leligth of
tlie light used. Inasllllll'h as the wave-
kngth of visihle liglit is ill tlil' region
IIf ()A to O.X I'. it is l'kar that Ray-
I('igh', 1:.\\' i, :1pplic!hk ,,"ly to very
,11\:111 particle, of k~s tlian ahollt
n.ns I' ~i/.l'. I'\('vnthel('", I~avkigh's
la\\' is of g<'II"1 al illtn('~1 ill l'xplaill-
illg Slll'h 1I:1[lllal pII<'III)I\\<'lIa as tll('
1111\<'I\<'~~ "f III<' cle:lr .,I,\' alld the
,,'dl\('" IIf ~lllIris<' alld Sllll>l'f.
''-'11' 1':lrli,'I,'s larger Ihall alll)\!t
n.ns /" thl' sl'atlnillg do('.s uot follow
:lIIV sill\pk 1"'\\'('1' law hilt changes ill
,I ('''lI\plicall'd IIlalilln fr"lIl the sixth
1)(1\\'('1' law of I\;l\'kigli t" a secolld
!>O\\'(T la\\' of particle diameter, tlie
latter lioldillg for parlicks sullStalitial-
h' larger thall the wav('lellgth of liglit,
~lIch particles exhihitillg true r('fle,-
lion.
The dft-,-t of partick siz<, on light
'<':Ittnill,g i, showli hv "rdillary to-
!>acco sll\oke. Nnvl.v-f"rllIed toi,acc"
SllIol", C"II~i'h IIf very fill<' tarry par-
tiel('s 11:1\'illl.; an avnage diall1etn of
a!>"lIt O,2S /' "I' w('11 !><,Iow tl\(' wave-
kllglh "f vi,d,I(' It,ght. ,'-;lIch a SlII"I",
'If'II(':II.' hilI<' !>\' ,cat(('I'('d liglit, Tltis
(',III I". ('xl":lill<'d 1111 1 lie ha,si~ tll:ll tll<'
1',11 tid,' dl:lIlIl't('l' is 1('"'' Ih:1I1 tll<'
,h,,, I(',t \":t\'('kI1i~tlt of visihle lil:hl
.11101 tll.ll ,IWldol(' III<' ,1\111' \\':t\'('
!<-nglll 01 1>111<' ligltl 1('1:11'" of till
vi,""(. '11'''''1<'111 \\"1 II(' n""t '1Ionl~
I, ", :1111'1 I'd Tol>,Il'('1I .',11\1'''(' :tIt,,\,
h,' i "I: (' \ 1 "", ,,j I,\, " '1110"('1. 1111 II I<'
11,11('1' h,lI\lI, :"""'''1', white' 01 ['r:tv
111"'.11\'." IIII' :IV('I':tI:I' I>:n Ii, 1(' ~i/,'
III IIII' ',11101", I"" 1)<'('11 gl (,,,tlv ill-
('1'":,,,'<1 h\' "olld"lIsa,ioll of ;\'alt'r
\'''1"'1' Oil IIII' l'"rti..I(', to a value
\\'('11 ,,111,\'(' fhl' wav('!('lIglh rang(' of
vi'lhle ligll1, !-'en ,lICh l':trti..I('s, light
(,f :111 \\'avekn[:lh" is s..attnt'd ahout
(''ually \\'('11 and th(' sll1ol,(' al'l't'ars
white ill whitt' light,
Particles largn thall a few microns
~..al ter light Ity t ru(' rdlection or in
prol",rtion 10 tll(' surface :IITa of the
I'articl(',. This fact is tile l'hy~ical
h:l~1S for oplical il"t 1'11111l'lIts u~ed to
nl<'asurt' Ih(' speeifi.. surfa..e~ of cer-
laill I,article SIISlll'lIsi( "",
Optical Density of Dispersoids
Suppose that a heall1 of parallel
light is caused to ,hine through a
hOll1ogeneuus, hut lIot lIecessarily UII-
ifonn particle size, dispersoid as
shown ill Fig, 14. The intensity of
the b('a1l1 will diluilli~h as it passes
(hrrmgh tlte dispcrsoid due to the
sidewise and ha,kward scattering of
the light. The law of extinction of
the heall1 may he d('rived for sililple
consid('ratious.
r.f'I the intensity of tl1(' hcalll elllt'l'-
ing Ih(' dispnsoid ,('II he I". Then
after travl'l'sing ,I distal)(,(' x, the
intl'nsity will II(' w('ak('lI('d to a value
I. Thr fnrthn los~ in inll'nsity 6.1
in p;\ssing throll.gh Ihl' thill layer 6.x
will he clo~,'ly pr0l'0rlioll,,1 -to tl".
iwident illlt'lisity 1 alld to till' thick-
II('SS of th(' layn 6." or Illatlll'nlali-
..ally
6.1 '..:.~ -kl 6.x,
wl1('n' k :ce' a ..onstanl for a giv('n
dispnsoid and d('pellds Oil the nllll1))('1'
of particles pn ullit volu1l1(' alld 011
particle ~ize, sit ape alld size di~trihu-
tion,
r .ettillg 6.x heCIIll1e infiuitesill1al,
the approxill1ation lIlay he writt('n as
an (''Illation in the ilifillit('silllais dl
and dx :
dl :c -kldx.
This CllI he illtegrat,'d hy ('II'IIII'lItary
Illethods. and yi('lds III(' inl('gra1 ex-
pr<,s.siou for I,
I (', k K,
wh('l'(' (' is tl". ('III \<'Ia lit of intl'g!al-
tillll To ('v:llu,,1<' (', il is lIo1<'d that
I It! wlt('I(' \ 0, So that
(. I", 11<-11..('
I I "I lox
'I'll;" flll'lnlll:l, \\'hi,'11 ill 1'1 I \',i...s i,
I
-------
56
Table 3
Particle Size and Concentration for Typical Industrial Dispersoids
Particl.
lOilding
Grid
Industry
Dispenoid
Electrical Powe,
Fly Ash from. Pul-
verized COdl
Electrical Power
Fly Ash from
Cyclon~ Furnace
k,ln Dust
Cement
Sleel
Blad Furnf1ce
after ["Y Du',f
(:otcher
Steel
()rc-Il Hearth f UrT1n
Copper Rnns!I'r
nu,.t
Non-Ff'rr,-qJ';
Smnlter'.
Non Ff'rrnlJ"
Sl11ol'('J',
COlf!V!'''!'! hn
n,'(.' r1u...t
Nt!n.f-nrr''IJ'.
Smoltp('.
R"" !~I h",."I!, '!)
~lJr n", !' 11u,.1
ChHrT'\tI ,"II
11,50. A, ,rJ
rrJrrH'
Ch~Jln" .,1
II"PO, A, ;,j
Fumr
a visually ckan stack. Tllis conc1l1-
sion is in agreement with studies
made on f\v ash emission in power
plant~ which have ~hown that a con-
centration nf the order nf 0,02 to OJ)]
g-rain',/ru ft i, th(' nlaxillllllll permis-
sible fen- th(' di<;charg(' to 1)(' illvi<;ihk,
Relation to Gas Cleaning Processes
Tll(' ~('paratioll of "1'1H'IIlI ,,( illI'I;lllnlh \Vhi,'11 ill
\',,!IT, I"r '''''111 '1 ,k, IIII' I'r"c,'",illg IIf
11I11~(' 'plalll ilil" "I 1IIII\I'r;d, alld "n',
ilS 111 '1IlI'llillg :llId Illl'lalll1rgy, or IIII'
'-<11111111'1 illil "I hl1ll1\"'d,, "f Illl'g,tlllllS
IIf '-11;11 IWI \ ..ar ;1' III Ih(' 1" "dl1Clioll
IIf ..k.-tri,' 1"'\\ n, ha\'l' gi\TI1 ri,,,' ill
th,' \' ...; ;dllll(' III IIII' t'lIli"If>11 of
IH'lh;lJ" :1' 11111,'11 ;IS ,SO tll 100 1ll,'ga-
IOlh )"'1 \ ";Ir "f ,'111111,1', dllS!, :llld
f'llil"
(;,1<" cll':l1lill~ pn1cc~,,(,'-1 Illa,\ II('
cl:1"lf\l'd l'rll:l,II\ ;IS 11llThailicai alld
,'k,'III,';1I :\ I ",-11;111 i,-:1I 1 Ir' ,,-,'s,e, ill-
clild.. ,111 tit"", \V1liclt c\"IIl'IHI fl1llda-
1111'111;111\' 1111 111I'l"tt:d "r IIH't'hallical
fOI,T, \'i/.. gr;1\ II \' ,,'lllillg, ct'litrifll-
~~,d "r ,\,,1"1111' ',('!'ar;tlillll, gas w;\.sh-
illg '" ',ll, l'or!Cclllratioll, C]('(--
I rical cond'lct ivity (ill ('I('CI rical 1'r('-
cil,itatioll) :lI1d agglol11eration chal-a,'-
tni,li,-,s, III additioll to th.. particlllak
1'1111 'nl it', it i~, (,r l'I}flr,,', l1l'Cessary
10 illcllld,' gas prlll'ni it", sl1ch as te111-
I'natl11T, 111Oistuf(' ,'on\('nt, total gas
fillw, ;lIld (-IH'l11ical corrosiveness,
IlIdlistrial dis1'l'rsllid.., arc charac-
tni,,'d hy n'Iati,,('ly high particle con-
("'lllr:llioll, ,1 "ny wide rang-e of
partil'''' "i/(', ;11](1 particle Silt'
-------
Section Four
/
DRY COLLECTORS
A. Cyclones
All About CYclone Collectors
B. Fabric CoIlectors
Primer on Fabric Dust Collectors
Fabric Filtration
C. Electrostatic. Precipitators
Electrostatic Precipitato"s
,.
/
,
..
-------
CYCLONES
D. James Grove*
I ~TRl)J1lll:1'I()N
Till' "\'l'll'l1l' ""JIl'"tor is '111 Inertial separa-
tOl' witilont movil1R parts where d confined
vort"x is fllrml'd which I'rOdUl'es suffi cient
("'l1trJ rn~a] for,'(' to drivL' th,' sw;pended part-
iculate' to the "ollector \vall. Although it i8
simp I!,. in,'xp,'nslvL', and ('an Iw constructed
!I'L'm m.II1Y m,ltl'rial>-l, ther!' an' few applications
whe'n' c")),,,:t[OI1 effJciendes exceed 80-90%.
('yclonl'" with d body diameter leHs than nine
lnchl's !I:}Vl: heen arbitrarily d<,signated as
"hiRh L'tficiency" cyclones. I\s will be shown
later, smaller body diameters create larger
separation forces, and consequently (up to
some practical limit) provide higher efficienc-
ies.
II
MECIIANJSH OF PARTICLf\ COLLECTION
Thl' basic components of d cyclone are shown
in Figure l. These include a cylJner, a tang-
C l.eaned-Gas r'~xi t
------ Cylinder
Dust Laden
Gas Inlet
Cone
Dust Hopper
Q
CoUected Dust
Figure 1.
MS Ie CYCLONE COMPONENTS
entlal gas inlet, n cone to deliver the
collpcted dust to a central disposal point,
oJ dust hopper, and an axial gas outlet, part
of whll'h L'xtends into the cylinder. The con-
fln,'d vortex of a cyclone Is Illustrated In
Fif!,ur<' 2. Th.. gas ent!~rs tang..ntlally into
tlH' annular :>pnce between the cyc1.one body
and the outlet tube, and spirals dO~lward
in what is called the main vortex. Near the
bottom of the cone, the spiralling gases be-
gin to move upward in the vortex core. The
spiralling action of the gases causes the
particles to be drIven to the walls by cent-
rifugal force, where they are moved towards
the dust discharge by the force of gravity
and the downward movement of the main vortex.
I t should be noted that the spi ral motion of
both vortices is in the same direction. The
tangential velocity (how fast the gases are
swirling) is lowest near the wall and at the
center of the cyclone. It reaches a maximum
at a point approximately 60-70% of the way
in from the wall to the center.
.~-
o
1,'-,
~.;
\.,..,
'..-.-:.'
,Eddy
Main Vortex
Vortex Core
~" ::.
Figure 2.
VORTEX AND EDDY FLOWS IN A
TYPICAL CYCLONE DUST COLLECTOR
DESIGN.
Not only are there variations in the tang-
ential velocity at different points in the
cyclone, there are also vertical eddies and
what is called inward drift. The inward drift
is a radial gas flow which moves toward the
center of the cyclone, opposing the movement
of particles. While vertical eddies can exist
in the cone, the most troublesome are those
present in the annular region near the gas
inlet. The eddies, which are caused by the
vortices and not by the gas outlet extension,
can carry particles directly from the gas
inlet to the gas outlet.
All of these variations combined together make
the problem 0 f de termining the separation forces,
and consequently the efficiency, much more
dlf ficul t.
PA,C.pm.104.4.73
*ChemIcnl I.:nglneer, Institute for Air Pollution Training
-------
III
DETERNINAT10N OF CRITICAL PARTICLE SIZE
AND CUT SIZE
d
o
= di.ameter of gas outlet, ft.
N
= number of revolutions the
gas stream makes (5-10 is
typical)
There are two sizes which are commonly used
to relate to the efFiciency of a cyclone. The
equations given for both of these are empirical
relationships, and their derivation will not
be presented hcre. They ~;ho\1ld not he used for
original calculations, but rather for comparing
the efficiencies of sill1il8.r r;yclones operating
at dlffl'r<'nt conditions.
Vi
- inlet gas velocity, ft/sec
p
p
= densit~ of the particulate,
Jbs/ft
p
3
density of gas, lhs/ft
The crlt[,'a! partlc1e si7.(' i~: defllwd a'; ,'he
size ,)! the' Hn1:JIJe,;t partl('I.' which call be
rc'movc'" r'ompl"~,'1y (relnovPc! with 100% efflcIL"H'Y)
from a dust ]a~H strenm.
~i~(11 do) ..
[IJ] -
P n- 271 N vi (pp - p)
11
= viscosity of the gas, lbs/
it-see
A size-efficiency curve i8 a plot of the re-
lationship between different sized particles
and the efficiencies with which they are
removed in a certain cyclone. An example of
such a curve is shown in Figure 3. If we
determine [D] from one of these curves, it
p cr
would be the diameter which corresponds to
where:
[1) 1
p cr
~ criticai particle size
])
= diameter o[ cyclone body, ft.
100
,-- -
.. -
t1I! '-
- 1--- - .. - .. ~ .. -_ ..
-- - ... " --." .,, ... .-
./
L -' --- - -' - ..
--- I- .. .- - '- - ,. --
/ . -- .. .- _u .h - -
11 .
J
II
'I'
-- - -' - - - - - ..
I .. ..-
80
:.,
u
,~
(jJ
'c4
U
'c4
'H 60
'H
rcj
r::
0
'c4
'-'
U
OJ
.-j 40
.-j
0
u
20
o 20 40 60 80 100 120 140
Part [dc Sjzt' - Mic.rons
J"igur<' L SIZE EFFIClENCY CURVE
2
-------
100% on the efficiency scale. For the curve
shown in Figure 3, the [D) would be approx-
p cr
imately 90 microns.
Since it is rather difficult to determine
[D) accurately from the graph, the cut size
p cr
is often ctetermined instead. The cut size is
defined as the size of the particle which is
removed \Jith 50% efficiency.
[Dp]cut=~ 92 P wi
7T N vi (pp - p)
(2)
where:
[D ]
P cut
= cut size
wi
= width of the gas in-
let, ft.
Referring back to Figure 3, the [D ]
be 12 microns. p cut
would
IV
PRI~SSURE DROP DETERMINATION
The pressure drop across u cyclone collector
will generally range between one and seven
inches of water and it is usually determined
empirically. An equation does exist which can
be used for relating the pressure drops for a
cyclone operating at several different condi-
tions, or for geometrically similar cyclones.
t\p
0.0027
2
k do Wj
Q 2
i
L " 1/3 'L . 1/3
L.( cv17 ,cone
1~ I-I
D \ D I
(3)
whe re :
t\p = pressure drop, inches of water
Qj 2 volumetric flow rate at the inlet,
cu. ft./sec.
1.[ ~ height of the gas inlet, ft.
L 1 - height of the cylinder, ft.
ey
Lcone - height of the cone, ft.
k
- dimensionless factor descriptive
of the cyclone inlet vanes
= 0.5 without vanes
1.0 for vanes that do not expand
the entering gas or touch the
gas outlet wall ("a" in Figure 4)
= 2.0 for vanes that expand the
entering gas and touch the gas
outlet wall ("b" in Figure 4)
v
CONFIGURATIONS AND RELATIVE DIPIENSIONS-
Effects of Cyclone Performance
The dimensions of a cyclone are of primary
importance when considering efficiency and
pressure drop. A widely recommended cyclone
with an ordinary tangential inlet would have
the following proportions, based on the cyclone
body diameter D:
Table 1.
Cylinder length (L 1) = 2D
cy
Cone Length (Lcone) = 2D
Outlet extension (into cyclone) length (La)
- 0.675 D
Inlet height (Li) - 0.5 D
Inlet width (wi) - 0.25 D
Outlet diameter (d ) - 0.5 D
o
Most design changes intended to increase
collection efficiency also increase pressure
drop. Conversely, recovering energy from the
outlet vortex is the only method of reducing
the pressure drop which does not also reduce
efficiency.
Increasing the inlet velocity will increase
the efficiency, although the relationship is
very complex. There is also an upper limit,
about 100 feet/sec, above which there is in-
creased turbulence which in turn causes re-
entrainment of the separated dust and reduced
efficiencies. The pressure drop will increase
as a function of the inlet velocity squared,
or twice the velocity yields four time~ the
pressure drop.
The length of the cyclone body determines the
residence time during which the particles are
subject to the separating forces, and increas-
ing this length will increase efficiency. Also
dust which has been entrained in the vortex
core will have more time to become reseparated.
Increasin~ the body diameter to outlet diameter
ratio will also increase efficiency, although
the optimum ratio is between 2 and 3.
As can be deduced from the definition of "high
efficiency" cyclones, decreasing the body
diameter will increase the efficiency. This is
due to increased separation forces caused by
the smaller vortex radius. In a very small
cyclone, however, the dimensional clearances
are so small that plugging occurs easily. Small
cyclones also experience bouncing of larger
3
-------
particles and local turbulence which reduce
efficiencies, and diameters of of 2 to 3 inches
seem to be a practical minimum.
The cone portion of the cyclone is not neces-
sary to convert the downward vortex to an up-
ward one, although its presence does reduce
the length of cyclone needed to effect this
reversal. The main purpose of the cone is to
deliver the collected particles to a central
pnint for easy handling and disposal. The
cone cannot be too small in diameter at the
bottom, or the vortex core will contact the
walls and re-entrain the collected dust.
I~sl discharge design is just as important in
reducing this re-entrainment, due to the high
turbulencl' and velocities present near the
discharge. The static pressure In the vortex
core may be slightly negative, and this will
tend to draw the collected dust up away from
the discharge. The best solution is some type
of mechanical device, sllch as a rotary valve,
a double-flap valve, a screw conveyer, or a
dip leg. To be successful, the mechanism must
achieve continuous, complete, and immediate
removal of the separated dust and prevent in-
flow of gas from the hopper.
As the inlet air enters the annular region at
the top of the cyclone, it is squeezed by the
existing gas to about half its inlet width.
This causes a significant pressure loss, which
..
can be reduced by adding vanes to the annular
area (see Figure 4). The presence of the vanes,
Figure 4.
INLET VANES
however, reduces the efficiency, apparently
due to the prevention of vortex formation in
the annulus. Helical or involute inlets (Figure
5) are attempts to reduce interference between
the incoming gas and the vortex already present
in the annulus. Axial inlets are free from
most of these problems, but they introduce new
problems. The inlet vanes must be designed so
that they impart adequate rotation to the gas,
and yet resist erosion and plugging.
Figure 5.
CYCLONE INLETS
-------
The eddy current in the annular region requires
that th., gas nutlet extend lnto the cyclone to
prevent excessive amounts of dust from passing
directly fr,'m the inlet to the outlet. Usually
this extpnsion ends just below the bottom of
the inlet. Uevices which permit the gases to
leave the gas outlet tube tangentially have
been successful in reducing the pressure loss
without sacrificing the efficiency.
Since the pressure drop in a cyclone is caused
by the vortex and not by wall friction, rough
walls actually reduce the pressure drop due to
the suppression of the vortex formation. They
also greatly reduce the collection efficiency,
due to increased turbulence and re-entrainment.
VI
CARRIER GAS AND PARTICULATE CliARACTERISTICS
Effects on Cyclone Performance
Changes in particle size, density, and con-
centration do not have a significant effect
on the pressure drop across a cyclone. As far
as the efficiency is concerned, however, this
is not the case. Efficiency will increase with
increases in particle density, mean particle
size, and concentration. The larger a particle
is, and the more it weighs, the better the
separation forces. The effect of increased
dust loading (concentration) is not quite so
obvious, but it is in part caused by the small
particles getting swept to the walls by the
many large particles.
From equation 2 or 3, we can see directly the
effect of the carrier gas properties on the
efficiency, in terms of the cut size or critical
particle size. A lower value for [D J or
p cr
[D J means a higher efficiency, and this
p cut
would result from a lower viscosity or a lower
gas density. Temperature and pressure will
affect the density and viscosity, although
this is not generally significant. A change
in pressure would produce only a slight change
in density, and a change in temperature would
increase one and decrease the other, with a
small net effect.
VII
TYPES AND ARRANGEMENTS OF CYCLONES
Individual hIgh efficiency, small diameter
cyclones have a small capacity, and they must
be operated in parallel to handle typical gas
volumes. They generally have a common gas in-
let, dust hopper, and gas outlet, and can be
arranged in banks of several hundred cyclones
each. A whole new set of design problems arises
with this arrangement, but it is advantageous
in that we can get a higher efficiency com-
pared to one large cyclone, with about the
same pressure drop.
Although there may be a slightly higher effi-
ciency using several cyclones in series, the
additional pressure drop is usually sufficient
to make series operation disadvantageous.
Occasionally a large dIameter cyclone is used
as a precleaner for small multiple cyclones
to remove the larger particles that cause plug-
ging in the multiple units.
VIII
FURTHER MATHEMATICAL CONSIDERATIONS
In order to obtain a prediction of overall
cyclone efficiency, a size efficiency curve
for a given cyclone under a given set of op-
erating conditions, and a particle size dis-
tribution are needed. The size efficiency curve
is characteristic of the cyclone, treating
the particular powder used in the test, when
running at the throughput of the test. Cor-
rections for differences in particle grading,
particle densities, gas viscosities, and gas
flow rates can be made using the equations
already presented, although care must be taken
in making large transpositions.
If the calculations are based on the cut size,
equation 2 will be the starting point:
[DpJcut
.. I 9)J wi
, 271 N vi (pp - p)
(2)
In order to determine the effect of the var-
ious parameters on the cut size (or the ef-
ficiency), a ratio is taken of the test cyc-
lone and conditions to the new cyclone and
conditions
[DpJcut I 9)J wi
(test) '271 N vi (pp - p) test (4)
=
[DpJcut (new) ~271: ).J wi
vi (pp - p) new
If, for example, the effect of changing vis-
cosity is to be determined, holding all the
other parameters (wi' N. vi' Pp' p) constant,
the ratio would be:
[DpJcut (test)
(5)
).J (new)
).J (test)
[D J
P cut (new)
5
-------
which can also be written:
[D ]
P cut (new)
[Dp]cut (test
)..I (new)
(6)
)..I (test)
By the same reasoning, the result of a change
in gas inlet velocity would be:
[I) ] ~ [D 1
P cut (new) P cut (test
i (test) (7)
Kepealing this procedure, the effect of
changing N. r> , and p l:an also be determined.
Lapple (5) stGtes that the above approach is
applicable only for geometrically similar
cyclones. Based on the dimensions given in
Table 1, Lapple presented a method for deriv-
ing the size efficiency curve from the cut
size alone. Once the cut size [D] has
p cut
been deter~mined, the efficiency for any size
particle D can be arrived at by calculating
p
D / [D) ,and then using the graph (Figure
p p cut
6) to determine the efficiency. For example,
if the cut size is 20 microns and we want the
efficiency for a 10 micron particle, D /[D ]
P P cut
is 0.5, and the efficiency is about 22%. A
complete size efficiency curve can be drawn
by getting the efficiency at several different
particle sizes.
99.9
i:J'.,.
I
;.,
u
t:1
<1J
''';
u
''';
'H
'H
~
t:1
o
''';
~
U
<1J
.--I
.--I
o
U
99
.---- .- --..
--- --- --
95
90
80
70
60
50
40
20
o --- .-:.-- .
o 5 10
-, - ---- - -
15
Figure 7.
6
;.,
u
(;:
<1J
''';
U
''';
'H
'H
~
~
o
''';
~
u
<1J
.--I
.--I
o
U
.~
.-
./
V
/
1/
V - --..-
.- ~.-I-
/ _.
tN:! 100
50
40
30
20
10
0.3040.5
4 5
3
10
Particle Size Ratio, (D /D )
P pc
Figure 6.
CYCLONE EFFICIENCY VERSUS
PARTICLE SIZE RATIO
(LAPPLE, 1951).
According to the Air Pollution Engineering
Manual (6), experimental data has compared
favorable with Lapp1e's correlation, except
for slightly lower efficiencies than those
calculated for D /[D] ratios of 2-3
p p cut .
Apparently, Lapple's correlation may be suf-
ficiently accurate for an engineering estima-
tion of many cyclone applications.
Gallaer (3) determined that if the size ef-
ficiency curve of a cyclone is plotted on
semi-log paper, a5 in Figure 7, a straight
----~---
20
25
30
40
45
35
SIZE EFFICIENCY CURVE
-------
.I
/
/
/
/
'/
,, ~
/'
/v -- -- --
IC 70 50 30 20 10 6 " 2
line results. The equation that represents
this line is:
E(d) = 1 - e
(xd
whe re :
E (d)
= fractional efficiency
of a particle with
diameter d
,\
~ partlcle diameter,
microns
11
= a constant for the
particular cyclone in
question
The particle size distribution of a typical
dust, when plotted on semi-log paper, also
produces a straight line (Figure 8). The
CfJ SO
c::
0
....
u 40
?
-:J
<1J
N
'M
'J)
<1J 20
rl
U
'.<
w
.... 10
-------
where:
y = a constant
Inserting equations 11 and 12 into equations
8, 9, and 10:
J\d) = 1
- (x/ [D J ) d
e p cut
(13)
Z,d)
-(y!l1J I ) d
t" p mean
(14)
x
-----
E'j'
[D J
P cut
(15)
----~---------
x
+
y
------
[D ]
P cut
[D J
p mean
With E(d) = 0.5, d = [DpJcut' and with Zed)
= 0.5. d = [IJ J . Inserting these values
p mean
into t'quations 13 and 14, it is found that
y = y. Equation 15 then reduces simply to:
Jo:'j' ~
[IJ 1
. - . - -- .£.-:nE"~n.- ---
[n 1 + [IJ J
" ('''I. P mean
(16)
'j'1"'rL'for<'. I r 'III' Jl\ean partIcle size it! known,
:llld II", ("ut Sl'~l' Is known. th" ov..rall effi-
,'iency call he Vl'rv quickly calculated.
Not only C.III the etfLcienl"y by calculated
origInally t rom this equation, but the effect
on the .>ffil'fpncy of changing either [I) J
p cut
or [I) J cun he quickly calculated. Before
p mean
using this method, however, it is imperative
to detennine if the distribution is truly
represented by an essentially straight line.
[ X
SUMMARY
Table 2"
--
l;as Flow
30 to 50,000 cfm (some to
100,000 cfm) smaller units
must be arranged in parallel
to accommodate large volumes
CnH Tl~mpcratun."
to 7',0° 'o'
6
Inlet Gas
Velocity
20 to 70 ft/sec (usually
about 50 ft/see)
Pressure Loss
0.5 - 2.0 inches of water
for simple cyclones, 2 to 7
inches for high efficiency
units
Particle Size
1 to 200 microns at vary-
ing efficiencies
High Efficiency
on Normal Indust-
rial Dusts with
Mean Particle
Size of
20 to 40 microns for simple
cyclones, 10 to 30 microns
for high efficiency units
Particle
composition
solid and liquid
Particle
concentration
down to .1 grains/ft~,
although usually above 10
grains/ft3, with no real
upper limit
REFERENCES
1.
Stairmand, C. J., The Design and Perfor-
mance of Cyclone Separators, Trans. lnst.
Chern. Engrs., Vol. 29, British, 1951~
2.
Caplan, K.J., All About Cyclone Collectors,
Air EnKineering, pages 28-38, September
1964.
3.
Gallaer, C.A., and J .W. Schindeler,
Mechanical Dust Collectors, J. A. P. C. A.,
Vol. 13, pages 574-580, December 1963~ -
4.
Kane, J.M., Operation, Application, and
Effectiveness of Dust Collection Equipment,
Heating and Ventilating, August 1952.
5.
Lapple, C.E., Processes Use Many Collec-
tion Types, Chemical Engineering, Vol. 58,
pages 145-151, May 1951. '
6.
Air Pollution Engineering Manual, 999-AP-40
pages 91-99, 1967.
-------
AIR ENGINEERING
Presents
.
Pri,ner
Dust
ONE of the oldest and most reliablt' methods
for the r('lnoval of solid particulate contami-
nants from air or gas streams is by filtration
throllg!! fabric media. The fabt'ic dllst collector is a
most versatile piece of dlll;t removal equipment, being
capable of virtually 100,:,;, removal efficiency on sub-
micron sizl'd particles. For controlling air pollution.
t he fabric collector with its fan or air mover can
be likened to a giant vacuum cleaner.
Although filters cover a wide range of equipment
types. this article will be confined to industrial doth
dust coiled ion apparatus as defined in "Webster's
Third International Dictionary"- -"A porous article
or mass (as of cloth, paper or sand) that serves as
a medium for separating from a liquid or gas passed
through it, matter held in suspension." The Industrial
Gas Cleaning Institute has defined a fabric filter as
follows: "A fabric filter is one in which the dust
bearing gas is passed unidirectionally through a fabric
in such a manner that the dust particles are retained
Oil th<, upstream or 'dirty' gas side of thf' fabric,
while the dcaned gas paSHCS I h rOllgh the fabric to
Ihe downHtrcam or dean gas sidp, whpnee it is re-
!TIOVI'd hy natural and/or mechl1nit'fll OWlllIS."
Commonly used types of fabric colll'c!.orB will be
discuBsed. including the variola; methods of cleaning
and fabric employed.
The fabric dust collecting apparatus has a wide
range of application. It is estimated that approxi-
mately 80':';, of all manufacturing plantG contain
operations which produce dust loadings and particles
small enough to warrant or require the use of this
equipment. Some of the more important application
areas are mining (both metallic and non-metallic),
chemical and allied manufacturing, food products,
rubber and plastics, l!xecious metal refining, primary
metallurgical, mechanical and electrical machinery.
Fabric collectors handle dusts from crushing, grind-
ing, pulverizing, conveying, milling, drying; fumes
PA.C.pm.l10.5.71
.
.
On
Fabric
Collectors
By H. K :Friedri('h
Manager, A.ir Cleaning
Buffalo Forge. Company
Buffalo, New York
Division
from open hearth, steel making furnaces, iron melting
('uvolas, reverbatory furnaces and electric arc fur-
nllccs; and carbonaceous smoke from incomplet('
combustion of chemical process streams as in carbon
black manufacture and fuel burning stacks.
Fabric collector applications cover the range from
nuisance dusts to product dust recovery. They possess
a distinct advantage over scrubbers in their ability
to recover dusts in usable form, ar.d have an advan-
tage over electrostatic precipitators in being able to
handle combustible and explosive dusts with safety.
There are two basic types of filtration that occur
in commercial fabric filters: namely, "media" or fiber
filtration, and layer or "cake" filtration. In fiber
filtration, the dust is retained on the fibers themselves
by settling, streamline contact and diffusion.
In "cake" filtration, the fabric acts as a support
on which a layer of dust is deposited to form a
microporous layer capable of removing additional
particles by sieving as well as by the other basic
filtration mechanisms. In practical industrial cloth
filters. both methods occur, but "cake" filtration is
the more important process after new filter cloth
becomes thoroughly impregnated with dust. A wide
variety of woven and felted fabrics is used in fabric
filters. Clean felted fabrics are more efficient dust
collectors than woven fabrics, but woven m'\terials
are capable of giving equal filtration efficiency after
a dust layer accumulates on the surface. When new
woven fabric is placed in service, visible penetration
of dust may occur until the "cake" or layer builds
up. This takes from a few hours to a few days for
industrial applications, depending on dUJJt loading
and nature of particles. For extremely low grain
loadings and for especially fine dusts, fabrics may
be precoated with asbestos floats or simil~r materials
to form an artificial filter cake that will prevent
this situation.
When using woven fabrics, care must be exercised
Reprinted from AIR ENGINEERING. May. 1967
-------
to prevent over cleaning so as not to completely
dislodge the filter cake, otherwise penetration will
riSt'. Over cleaning of felted fabrics is generally
impossible hecause they always retain substantial
dust depositA within the fabric. Felted fabrics require
more thorough cleaning methods than woven mate-
rials. For the same cleaning efficiency, felted fabrics
arc capable of higher air-to-cloth ratios, i.e. cubic
feet per minute per square foot of cloth, than woven
fabrics, therphy requiring lesl3 filter cloth area and,
consequently, Jess space for a given air or gas volume.
ThiA is balanced by the higher cost of the felt fabrics
and the cleaning method employed. Woven fabrics
arc available in a greater range of temperature and
corrosion-resistant materials than felts and, therefore,
coVt'r a wider range of applications.
The fabric is often referred to as the "heart-of-
thc-qust collector" and its selection is most important.
Dust characteristics (size, shape, stickiness, etc.), gas
composition, gas volume, temperature, corrosive
conditions. equipment design, and past experience
must be evaluated when selecting a suitable fabric.
Therefore, filter fabric changes should not be made
without the original equipment manufacturer's advice.
Often, performance can be affected adversely, by
inappropriate filter materials. Some of these fabric
limitations are as follows.
Figure 1 illustrates fabrics that are presently
applied in commercially available collectors. Glass
fabrics are capable of service up to 550°F., but the
fibers of glass fabrics must be lubricated with
graphite or silicone oils to prevent breakage of the
fibers during cleaning. Other materials less commonly
used are metal and ceramic fibers that will filter
gases at temperatures as high as 1600°F. There is
Figure 1
little operational data available on these fabrics and
they are extremely expensive. Woven cotton is still
the material in greatest use today. Filter fabrics
are often given special treatment such as flame
retardation, heat-setting to combat shrinkage, and
silicone coating to reduce dust adhesion.
Distinguishing features of commercial cloth ftlter
units are the type and arrangement of filter cloth,
method and frequency of cleaning, and filtration rate.
The various techniques used to remove dUlt accumu-
lations from filter surfaces and the fabric arrange-
ments that may be used with each method of cleaning
are as follows:
Cleaning Method Fabric Arrangement
1. Mechanical shaking Tubes or screens
2. Reverse flow by reverse jetting Tubes or bags
Reverse flow by pulse jetting Tubes or bags
Reverse flow by bubble Tubes or bags
3. Bag collapse by reverse flow Tubes or bags
Mechanical shaking is the oldest and most widely
known fabric cleaning method. There are today a
number of variations of this basic cleaning method
in use. Shaking bag collectors with woven cotton
fabrics probably account for 50% of fabric collector
sales. This type has evolved in its several forms
over a period of more than 50 years. Improvements
have been largely confined to the various modes of
mechanical shaking.
Figure 2a is a schematic illustration of a typical
shaker-type fabric dust collector. The filter surfaces
are arranged as inverted tubes with the dusty air
entering from the interior into the lower tube sheet.
Coarse, or heavy particles drop into the dust hopper
in this low velocity section, whereas the fine dust
deposits on the inside of the tube. Cleaned air then
F, L TE.R fABRIC CH ARt..C TE RI 511C5
FIBE.R O"~A....'tI"'. SVPpQ..n 1\111. RE.~'~TA.I'4C.E. E - E.1I~e.~L..~NT
E1IPo~oQ.~ PU.t1t".'~lt ~ - GOOD
L,Mon Cf~S4.h - FAIR.
CONTE.I'H (0 "1e\.l'TIOtI p- 1-"00",
-f H I!."''' Aelas
A &Il" ~IO'" ALI("Lle~ O"OI~I"c;, SO,""'"U
Lo..u ~T "ora t. ~.~:.~'). O.'C t10lsT Hue........ 0,,<0..".1: AGouu ~
Conof'\ 180 ZZS '(f.~ 10 - z.. G G G P G G F E.
WOOL. Zoo lSO 1'(0 2.Q'<,o C, F F F F P P F
OR.LO,,", Z40 215 YQ~ 2.0-45 G '" G G G F G e.
D...cczo,,", 215 3ZS Yu IO.Cev E. G F Go G G r:. E
N-'LOH Zoo Z50 Yn IS-?> ~oo 600 No 10-10 P E. E. E E. P E E.
fk.1~,lt"l ZOO ZSO Y..~ 1'~o E. G; F E E. E. CD G
NOM£.~ 425 SO<> No z~.s~ E. E E. F e. CO G E.
TEj:'LOI't 450 Soo No 15-'-5 F' E E E.. E. E. E. E.
-------
filters through to the clean air chamber and is ex-
hausted from the filter house with the aid of a fan
or other air mover. As filtration continues, dust
cake accumulations increase the pressure drop across
tll(' tubes.
Figure 2a
(LeAH
A.lfl.. ..-
£ ...~~U~ T
o~'--
MECI-t""'~""
FoR. 5~~'f(.\"tO.
R"9P'''' ~ 0"-
V, 0R"T I~"
':r
Du:n
D\,;)C~~R,""E
B,,~,c (L01H \U6E.
~HA~E.~ 1'1'PE
For extremely light dust loadings (e.g. atmospheric
dust), the period between cleanings can be several
months, but for the usual range of industrial load-
ings it is usually a matter of minutes or, at most,
of a few hours. Before excessive bag resistance to
air flow occurs, the filter tubes are shaken to remove
the dust by mechanical rapping, vibrating, or some
other means of flexing the fabric to dislodge the dust.
I<'requency of shaking depends upon the dust loading
and type of dust. Small units (less than 3000 dm)
fire often shaken manually. With large filters, the
normal procedure is to utilize automatic pre-set,
timer-operated shaking devices that utilize mechani-
cal-electric or pneumatic power. Cyclic shaking and
eleaning is timer-regulated to control length of cycle
as well as shaking period. The timer can alBo actuate
the system air valves as required and prevent exces-
sive shaking, which would tend to destroy the basic
desirable filter cake required on woven fabrics.
When dust loading only occurs intennittently and
when the unit can be turned off periodically for
shaking, the collector may be designed to operate
for some number of hours (such as 4 to 8) without
interruption and then to shut down completely for
some period of time for fabric cleaning.
When continuous operations are required, espe-
cially when the type and concentration of dust require
frequent cleaning, units can be arranged to run with-
out interruption for prolonged periods with the use
of multi-compartmented shaking bag units. as shown
in Figure 2b. Uninterrupted flltering is accomplished
by shutting down one compartment at a time for
cleaning, while the remaining compartments are
handling the entire air volume. To maintain constant
system pressure, additional compartments may be
added so that one compartment is off-the-line con-
tinuously.
Figure 2b
t.,~,~ ...
0", (OMP"<.T ,."oq
SW~K ''1<; I i5Au'NCE tllffIC: ''1<;
FiCCo l b.
--
ALL (OJo1PA.ft TMe....T~
tlL Tee'",101 ""~E~\ Ort:~
Figures 3a, 3b, 3c, 3d, 3e
" - r1~
,
./
.-/
;;: : '- . , ---
, -~
,. .----
" "
-
, ' '.'
--,'I
,
,
,
-H
,
,
,
\
U
O~('\.l..l''''o.:. JIT 51o\'",{
(&..-.)
~" 3c rl6 3d f"1~ ~ ~
,
A... ~~,,~
(k'hl"" h......)
\ IC". ~..
SO..,C.
f"... ~h
T ~PI("l B... elf ""'NC.
'1"'11100,",
Figure 3 illustrates typical bag cleaning methods
used. Combinations of these dust removal mebhods
and bag arrangements are often used. Cleaning can
be accomplished by reverse flow of air (Figure 3a),
whereby cleaning takes place partially by the dust
removal effects of reverse flow and partially by
flexing the fabric. Separate fan systems are often
employed to provide the reverse flow of air.
Low frequency sound waves (Figure 3b) which
cause the bags to vibrate sympathetically, are .used
-------
alolw or in ('ombination with reverse air flow to
dislodge the collected dust cake.
A nol her cleaning variation I Figure 3d, which
pl'ovidf'~ a "shake" that is more gentle than me-
(' !tanka I shaking. is 10 indllce n n oscilIating flexing
mol ion. AI~n applil'd is an air jet or "bubble" (Figllre
:\d) I hal iH illjl'('\"d into Ihr lop of the lube internally,
Ira vt'\ing down I he length of lhe lube, breaking up
I lit' dllst cakf' aH it progreRi:WS. These four methods -
re\'erH(' flow. sonic, oscilhition and air jet-have
particular value for glass fabrics which are more
frngilf' than other fahrics and more subject lo pre-
malll re faHlln' from overflexing. The typical vertical
mt'chanical aha king melhod of dislodging dust cake
is also shown for romparison in Figure 3e.
Shaking bag units of the type ilIuslrated in
l<'igurps 1 and 2 employ bags or tubes that are 4"
to 12" in diameter and freqllently as long as 40 feet.
Figure 4a
') tI"kl"~ ~f( ~A"'\"
01{ (",I
I i?cv8«se f'.....o....) ~;;
t-'\ "NI~~') \"
v/
Capacity of singlt' inslallations is limited only by
the difficulties associated with distributing the air
to each compartment of large structures. Air-to-cloth
ratios are usually Jess than 5 cu ft per square foot
of fabric, sometimes as low as 1 cfm/ft2 for metal
fumes. Glass fabric bags are used in diameters as
great as 12" and air-to-cloth ratios range from 1
to 2.5 cfm/fP
Figure 4a shows another form of shaking bag
collector. In place of vertically hung tubes, fabric
envelopes are stretched over rectangular screen
forms. The dust collector consists of a series of
FIgure 4b
C Lt;..1oJ
A,~
Dv ~T .D~PO!>'1
~ 0.... CLo,",a ~"Qr
~ ~-~~~;~: ~?
..-- ;
Q
----
~
'--
Du~T L~DE'"
~\St ~,"-ouJ
S"H~'.
T~.u..... ~'v.t'" "FL,,"-'" 'M".".", C)"I.IoII"~'
I 1~"'\COLO ,.. . t-'1_......,-o ~'''CI'",v".to\
Re.vee~t. FLow
The reverse flow principle is also utilized in the
pulse-jet unit shown in Figure 5. This is the newest
advance in the field of fabric collectors. having been
introduced about 10 years ago.
Figure 5
'R~v "11 S. fL()\AJ -T'4p€
(\>".."': . J"-I)
e....... A...
O"llq
.,) 'W,.t "l?".'W4'1
T.qu
1\....
A pulse-jet unit consists of a conventional filter
housing with closed bottom tube-type filter elements
supported by wire retainers. After dust accumulatea
-------
11(\ IIH' exterior Hurfaces of thc tilter elements, clean-
ing- iH accomplished periodically by reJeasing jets of
high velocity air through a Venturi tube mounted
above each filtl'r clement. The high velocity air jets
are produced by compressed air at 80 to 100 psi
and an' controlled by solenoid valves actuated by
an adjustable electrical timer capable of varying the
cleaning cycle. The high pressure air induces sec-
ondary air flow sufficient to flex the entire length of
the filter tubes. Pulse duration is approximately
'](I second and bags are cleaned sequentially, making
this a continuous-duty unit with minimum filter cloth
area.
..
Units are constructed in modules and large capaci-
ties may be achieved by combining modules. Felted
fabrics are used with air-to-cloth ratios of 7-15 cu ft
of air per square foot of cloth area. Bags are 4%"
in diameter and limited to 8' in length. Gas tempera-
.tures as high as 450°F can be handled when using
TeHon fabrics. Typical compressed air requirements
are 1-2 scfm at 100 psi per 1000 cfm.
The bubble type unit illustrated in Figure 3 is
a variation of the reverse flow-pulse jet unit and
utilizes bags as large as 12" diameter and 25' long.
Figure 6 shows a reverse flow unit that uses a
t ra ve ling reverse air jet. It was introduced about
20 YCi1rs ago and many refinements have been intro-
duced during recent years.
Figure 6
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The fabric tubes with top inlet are contained In
a conventional housing similar to that used in the
other units already discussed. The heavier particles
pass directly through the tubes to the hopper, and
the finer particles accumulate on the interior fabric
surface. The cleaned air passes outward through the
filter element to the clean air chamber. As the fine
particles accumulate, air flow resistance through the
filter media increases. At a pre-determined level, a
differential pressure-actuated switch activates the
slotted blow-back rings and the reverse jet supply
blower. The blow-rings, located around the outer
circumference, traverse up and down the fabric tubes,
slightly indenting the fabric. The high velocity air
jet, released from the narrow slots in the ring,
penetrates the fabric and combined with the flexing
action of the rings on the fabric, dislodges the ac-
cumulated dust which drops into the hopper assisted
by the downward flow of air in the filter tubes.
As the filter cake is restored by. the cleaning
action, filter resistance is reduced. When th(e re-
sistance is reduced to a pre-determined level. the
pressure switch stops the blower and blo",,:,-ring
assembly until cleaning is required again. The fabric
is cleaned while it is filtering and the frequency and
duration of filter cleaning are a function of, dust
loading and dust characteristics.
Because the reverse-jet unit operates at full air
flow while cleaning, continuous service is "built-in"
without the need for compartmentation, dampering.
valves or complex cleaning methods. .
Filter elements are up to 12" in diameter and
as high as 22'. Felted and woven materials are used
with air-to-cloth ratios as high as 30 to 1. Collectors
are modular in construction and air flow capa~ities
are unlimited. Glass fabrics are not used with reverse-
jet cleaning filters so maximum temperature limita-
tions are determined by natural and synthetic fabric
properties. Jet pressure is approximately 1 psi.
Reverse jet air does not add to the system filtz:ation
requirements because a separate blower, usin~ out-
side air, provides the needed flow. r
Proper application is a most important aspect of
all successful air cleaning installations and for all
types of fabric collectors. A brief outline of many
of the factors required for proper fabric collector
selection follows: .
1) Gas Flow-normal :lnd maximum gas flow.
Cubic feet per minute (cfm) or Ibs per hour.
2) Concentration of Solids-average and peak.
On a weight related to gas volume flow.
3) Size Distribution of Solids-mass median
diameter and geometric standard deviation. This can
be satisfied by furnishing to the collector manufac-
1
turer a representative sample of the dust to be
handled.
3) Properties of the Particles-hygroscopicity.
deliquescence, chemical stability, explosiveness, ten-
dency to agglomerate, electrical behavior, abra,sive-
ness, bulk density, specific gravity, etc.
3) Properties of the Gas-combustibility, cor-
rosiveness, moisture content, density, minimum and
maximum temperatures. etc.
6) Environmental-physical space limitations.
Indoor or outdoor Installation, etc.
This brief look at the types of fabric collectors
available for air pollution control and product recov-
ery should indicate that although they. are by no
means capable of handling all air pollution problems.
they can solve many dust collection problems where
properly applied. All cleanable industrial fabric filters
are capable of giving very high collection efficiency
(99.9% by weight) and can operate over a range of
air flow resistances depending on air-to-cloth ratio.
For equal collection efficiency and resistance, com-
mercial units may vary in size, operating, and mainte-
nance requirements, but generally they will cost alike
on a totally owned basis and will have closely similar
power requirements. .....,
-------
G. W. Walsh':'
FABRIC FILTRATION
F'\BH.IC FILTRATION
TYPI':S i\ND SlZI';S
EQUIPMENT
,\
H~ sic n Ili t
111 11 S sllllpll'sl form, tlH' indui-5trial r~bric
fill,'1' (b~ghollsd ('ollsi:::;ts of a woven or
fdkd fauI'il' tht'ollgh which dURI. laden
g~1 SI'S ;l1'e fOt'I~l'd. i\ I'ol11uin<11 ion of f~ctorl'
t'('sull ill till' I'ol1l'(;l.ion of r~lrticles on the
f~bl'i,' fibe)'s, When WOVt'n fabrics are
used, :1 dust cake eVt'ntually forms which,
in turn, ads prl'donlllJCllltly as a sieving
!nt'ehanism. When felted fabrics are used,
tins dus t cakL' is minimal or non-existent.
Instead, the main filtering mechanisms
arc a combination of inertial forces, elec-
trostatic forces, impingement etc., as
['ebted to individual particle collection on
single fibers. These are l'ssentially the
same mechanisms experienced in "Air
Cle3.uing Type" filters.
As p8 rl.iculate:::; arc collected, pressure
drop across Ihe filtering media increases.
Becau:::;e of fan limitations, the filter must
he denued. 1'hi:::; cleaning is accomplished
"in-p]acp" StOCC the fdter area is usually
too large and time between cleanings too
short 10 allow for filter replacement or
deuning external to the baghouse.
111 ord('I' 10 !nt'et the challenge of a variety
of ope rating condition:::; and applications, a
mult itude of (>l'opriet;lry designs exist.
Ei-5sential di fferC'nces are rcIated to:
Fabrk
2
Cleaning I1lcchanism
:{
I';quipmcnt geometry
4
Mode of operation
Dep('nding on I.h(' above
will follow Ollt' of I.h ree
in Figure 1. 1.
factors, equipment
systems, as shown
Figure 1. 1a shows "bottom feed" units in
which the dust-laden gas is brought through
the baghouse hopper and then to the interior
of the filter tube. Obviously, a portion of
the dust is removed in the hopper and neve,r
reaches the fabric.
Figure 1. Ib shows "top-feed" units, in
which the dust-laden gas enters the top
of the filter tubes.
Figure 1. lc shows units wherein the gas
passes from the outside of the filters to
the interior, or clean-air side. With this
arrangement, the dust inlet can be located
in many positions. The fabric can be
formed in a tubular shape, or it may be
in an envelope form.
B Baghouse Operation
1
Intermittent operation
The fundamental principles of operation
are embodied in the discontinuous-type
or intermittent units. For such filters
the entire area collects dust for a pre-
set filtration time; at the end of this
time the unit is taken out of service and
the whole area is cleaned of collected
dust. Examples of such collectors are
shown in Figures 1. 2, 1. 3, and 1. 4.
These collectors are primarily utilized-
for the control of small volume opera-
tions such as grinding, polishing, etc..
and for aerosols of a very coarse nature.
They are also used extensively for pilot-
plant studies and research. Many of
these baghouses are of the so-called
"unit" type, in which the fan and filter
are contained in a single piece of
equipment.
2
Continuous operation
For most air pollution control installa-
tions and major dust control problems
it is desirable to utilize collectors which
'~(-;hicC J\;~'-l~)Ti~;lCon Training, Training Program, SEC
pa . c . pm. 90 . ;. . (j(,
1
-------
(a) Bottom Feed
Figure 1. 1
I -:"
I -
C"
_.
-
I -:"
-
::-
t ~
-
_.
,
, -
I
I
(b) Top Feed
(c) Exterior Filtration
POSSIBLE FILTERING SYSTEMS
-------
I-
I
L
Fabric Filtration
, ...
-------
Fabric Filtration
allow for continuous operation. This
end is accomplished by arranging
several filter areas in a parallel flow
system, and cleaning one area at a time
according to some pre-set mode of
operation. Examples of these control
devices are shown in Figures 1. 5, 1. 6,
and 1. 7.
In a multicompartment baghouse the
basic filter area is a compartment or
section (see Figure 1. 5). Each section
or compartment is essentially the same
as a discontinuous unit. In a reverse
flow baghouse the basic filter is one
envelope or filter bag (Figure 1. 6).
Whereas a small portion of one filter
~ube is the basic filter area in a re-
verse jet baghouse (Figure 1. 7).
C Filter Cleaning
The heart of any fabric collector is the
technique employed to remove dust from
the fabric. There are two general types
of cleaning; the first involves flexing the
fabric and the second involves a reverse-
flow of clean air. A breakdown of these
types is as follows, according to com-
monly accepted terminology:
1
Fabric flexing
a Mechanical shaking and rapping
This type of cleaning generally in-
volves the use of a "rocker arm-
lever assembly" to produce a motion
to the top of the filter tubes. The
motion may be generally horizontal
(sometimes concave upwards, Some-
times concave downwards), vertical,
or cover a 900 arc from bottom to
top of swing. Vertical motion is
sometimes accomplished by rapping.
b Sonic cleaning
This type of cleaning utilizes sympa-
thetic vibrations from sound waves
to dislodge dust from the cake.
Sound waves are generated at low
frequency by means of an air horn.
4
Figure 1. 8 shows a typical location
of sound producing horns on the
clean-air side of the filter tubes. (1. 1)
c Collapse cleaning
To clean filters by the "collapsing"
technique small reversals in pres-
sure are created, such that A P
from the dirty air side to the clean
.
air side is slightly negative. This
causes the filter tube to deflate, and
hopefully, the dust cake is discharged.
In some cases, the tube is slowly
collapsed and "popped" open. If
desired, the bags can be collapsed
several times per cleaning period.
Obviously, the baghouse must be
equipped .with suitable valves and
ductwork to achieve ~ P reversal.
d Pressure-jet or pulse-jet cleaning
For this method a "bubble" of com-
pressed air is injected at the top of
the filter tube. A schematic of the
bubble as it travels down the tube is
shown in Figure 1. 9, i~ corbination
with collapse cleaning. 1. 2 Arrange-
ment of the system when filtering on
the bag exterior is shown in Figure
1. 10.
2 Reverse-air cleaning
a Reverse-jet
This mechanism employs a high
velocity (small volume) jet of com-
pressed air, blown back through the
fabric, to dislodge collected dust.
Figure 1. 7 shows the usual arrange-
ment of mechanical cleaning devices.
In the typical "reverse-jet" filter
unit, cleaning can be conducted con-
tinuously, so that pressure differen-
tial across the unit tends to remain
constant.
b Reverse -flow cleaning
Both filter tubes and envelope col-
lectors can be cleaned by a reverse
-------
-- - - . - .
'- - ~- - ----------- -----'---
Fabric Filtration
----'
Fi lteri n9
Fi lteri ng
Fi lteri ng
Shaking
Filtering
Filtering
..- ~
to fan to fan
All compartments filtering, dampers open One compartment shaking, balance filtering
incoming gases incoming gases
--.. .. ~ ~
i" (" 7'1
Fi lteri ng Shaking Fi 1 teri ng Fi 1 teri ng Fi 1 teri ng Shaking
,.
to fan
One compartnEnt shaking, balance filte~ing
to fan
One compartment shaking, balance filtering
Figure 1. 5 TYPICAL PARALLEL FLOW SYSTEM FOR A
CONVENTIONAL MULTICOMPARTMENT BAGHOUSE
5
-------
Fabric Filtration
----
~NlforD t)lUVf
,um ...01011.
DUST Srof
CAS'N'
'Rtvt'RSf AI'R
ClfAN.N;
MANtfOll1
AID WtW.
MANlfO!D 1nUYf
AND IMAVU
I
I
I
I
I
I
, I
I
I
I
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" fl11111. 'lABI
WAJJ.WA Y
C1£A~ AI'R SIDf
.' 'RarA'RY'Dls..1f
VAJ.V£I
- --.-.....I
Figure 1. 6 CONTINUOUS OPERATING ENVELOPE COLLECTOR
WITH REVERSE-FLOW CLEANING MANIFOLD
-------
Fabric Filtration
",.,
.r
REVERSE JET
(Koppers Co., Inc.)
Figure 1. 7
7
-------
Fabric Filtration
Figure 1. 8
AIR HORNS WHICH AID IN CLEANING BAGS
\
BUBBLE
'~
Figure 1. 9
PRESSURE JET CLEANING
8
-------
- - --~- - ---v-
Fabric Filtration
--------~--- ------~-------~-~
-- --
'111: ,
'.t 01
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(O"'P"ISID
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iUPPLT Af
'00 11.1,1.0.
o Q ,~;I.' ~-_.
1'1 1'1
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UH~~ml . ~ (". Ii 0 [! J I!i.
~.. ~.. L. U IIHOU(IOnOW
... ""fl (YIIHOfU ' ,- .. [r:. ~ 'n."~,{t!, J
. WIIf anAINIU ~ : \.J ~~:lf ~t I
r ~~~~l~'EO;:'~~(1 ,fiP~': .Ifl)' *-:
G. SOLINOID VAlVI I~ II I "
H. JlMI. I . - , '
J. AIR MANifOLD ; /1 ",. . ~.
k. (0...00. HOUSINO \ ''l~i'... ..).
l. INln . 1~l.~ . :~,. . ;!
M. HOIIP(R ,I J \'1 '. : I'"
N. AIRLOCK \,; .'. ~ U' :
O. IXHAU$T OUTUT I ),:' :.. . :,~
p, MAHOMm. ~"-JI - t'':.:'\'~ "1
Q. U""'. PLINUM ~. ';-'_:-~.'-'_:' 7-+~~'it
-1~I:.. ~~~..., . ,if'
'M .,;. , ..:
~".,.".,~:., ~:
J
H
..
K
--
Fl~~ur(' 1. 10
110\\' of clcall C\ ir. This would be al
low or atmosplwric pressures, and
would utilize a much larger volume
of air than the reverse-Jel action.
An arrangement used for envelope
collectors is shown in Figure 1.6.
In this case, the cleaning manifold
I raverses the baghouse length,
cleaning one row of envelopes at a
lime. Filtration, of course, is on
lhe outside of the envelopes. An
::lrrangcment used for tubular bags
is shown in Figure 1. 11. Note the
rings whil'h a rc used 10 maintain
filler shapt'.
[)
H:lgh'HISl' Siz('
Bag filleT' lllUls .\n' J'('lativl'ly large in so
far a~, dust colledion ('fJuipmf'nl is eon-
CI~I'Ill'd. 1':quipmcIlI !il7.(', theT'erorc, iH of
impor.tanl'(' 10 the hU'y('r' as a matter or
('c()Jlomi..s and f();u,;ibilily.
For given manufacturers, the nominal
filter velocity is a major factor in deter-
mining equipment size. This does not
mean, however, that different types of
units vary in size according to lheir rated
nominal velocities. Other factors, such
as height limitations, bag spacing, and
the length to diameter ratio for tubular
bags, arc also important. Table 1. 1 lists
approximate size ranges for various cate-
gorics of fabric collectors, at nominal
velocities of 1 fpm and at nominal veloci-
ties considered as normal for the particular
collector.
E Filter Fabric
1
Types of fabric
Filter fabrics can be divided into the
woven or felted classifications. If
felted fabrics are used, filter cleaning
is limited to the pressure-jet and
reverse-jet classifications. When
woven fabrics are employed any clean-
ing technique may be used. In practice,
however, bag collectors cleaned by
the reverse-jet technique operate at
relatively high filter ratios. To ensure
high efficiency and 10 maintain low
pressure differentials these collectors
usually employ felted fabrics.
Woven fabrics can be sub-divided into
the following classes:
a
Continuous-filament type, in which
the filaments used to form the fabric
strands are continuous in structure.
Such a fabric is characterized by a
smooth surface and absence of fibers
or tendrils, and can be constructed
only of synthetic materials.
b
Texturized strand, in which the
fabric st rands are mechanically
degraded or broken al the surface
to produce a fuzzy thread. The
texturized strand is usually woven
in the fill dircC'tion.
c
Staple strand, in which the fabric
strands arc formed from short
9
-------
Fabric Filtration
INSPECTION DOOR
SPREADER
RINGS
CLEAN AR
TO FAN
DUST LADEN
AIR INLET
~
AIR REVERSAL "'LVE
IN NORMAL FILTERING
POSITION
AIR REVERSAL VALVE
IN BACK-WASH POSITION
-,/
i i 1
BACK-WASH AIR
THIS COMPARTMENT
FILTERING
THIS COMPARTMENT
IS BEING .BACK _SHED
WITH CLEAN AIR.
ACCUMULATED DUST
DROPS INTO HOPPER
FILTER TUBES
PARTITION
HOPPER
UNIFLOW-BACKWASH DUST COLLECTOR*
Figure 1. 11
-------
Table 1.1
APPROXD1ATE SIZE RANGES FOR FABRIC COLLECTORS
Collecto~ volu~e(l) Collector l: (2) Collector volume Collector
Collector Uf per 1,000 cfm Floor-Area per 1,000 cfm Floor-Area
(ft3) f (ft 3)
(fpm) per 1,000 cfrr. (fp:n) per 1,000 cfm
(ft2) (ft2)
Reverse-Jet 1.0 1,250 57 - 294 10 125 5.7 - 29.4
(3) 1.0 670 111 10 67 11.1
Pressure-Jet
Conventional
tubular bags
Mechanical 1.0 210 - 370 26 - 50 3 70 - 123 d.7 - 16.9
Reverse
flow 1.0 590 30 -' 42 2 295 15 - 21
Envelope 1.0 210 - 340 21 - 59 2 105 - 170 10.5 - 29.5
(1)
(2)
Does not include dust hopper.
Common values for filter velocity.
(3)
As manufactured by Pulverizing-Machinery Company, N. J.
....
....
i
I
I
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1::1.
(")
......
~j
.....
::;'
'1
I!J
~
o'
~
-------
~'abric F'iltration___-
1'11;\lI\('l1t:-;. '['hi::; type of con::;truct!on
is lH~t'l'ssary for the natural fibers.
'I'11f' fabric i::; charactenzed by its
I'uzzy appf'arance and forms a most
dficient filter because of the fibers
and tendrils which mat the surface.
of applications for the reverse-jet
units is limited to temperatures
below 2700F and to dusts low in
alkali content.
a
Insofar as the materials of construc-
tion a]'(' concerned, prime factors
of imparlance are temperature limi-
tations' and chemical stability.
Other factors which should be evalu-
ated include "air permeability, "
resistance to abrasion and shrinkage.
Table 1.2 lists some generally
accepted properties for various
mate rials commercially available
and in use today. Since felted
I'abrics arc made from wool and
adem, it l'8T1 1)(' seen that. the range
b The actual weave patterns used for
a fabric will influence the filtration
process. This will be discussed
in greater detail in later sections.
Some concept as to why the weave
pattern should influence filtration
can be obtained by microscopic
examination. Figures 1. 12, 1.13~
and 1. 14 illustrate the fact that
significant changes occur as both
materials of construcli0fu and weave
patterns are altered. 1. 3 Details
of the fabrics shown are listed in
Table 1. 3. These differences be-
come especially significant when a
scale on the order-of-magnitude of
particle diameters is used as a
reference.
~
Fabric pt'opf'rties
12
-------
Fabric Filtration
---
Table 1. 2
PROPERTIES OF FILTER FABRICS':":'
Melting _..... Acid Alkeli Flex
FABRIC Contln-
T llllpenture Oporotln. Resistance Resistance Abrasion
Tem,.,n,,..
Cotton Decomposes at 180° F Poor Very Good Very Good
302° F
Wool Chars at 5720 F 2000 F Very Good Poor Fair to Good
Nylon 6, 6 (I) 480° F 2000 F Fair Excellent Excellent
Chars at 700° F 4000 F More resistant than Not as resistant as Good
HT-1 (II Nylon; inferior to Dac- Nylon; superior to Dac-
ron & Orion. ron & Orion.
4820 F 2WF Good to most mineral Good in weak alkali. Very Good
Dacron (I) acids. Dissolves partial- Fair in strong alkali.
Iy in concentrated
H2SO..
Orion (I) 4820 F 2600 F Good to excellent in Fair to good in weak Good
Softe ns mineral acids. alkalis.
Creslan (2) 4750 F 2500 F Good in mineral acids. Good in weak alkalis. Good to Very Good
Softens
Dynel(3) 3250 F 1WF Little effect even in Little effect even in Fair to Good
Softens high concentration. high concentration.
Polypropylene 3330F 2000 F Excellent Excellent Excellent
Decomposes at 500° F; emits Inert except to fluorine. Inert except to chlorine, Fair
Teflon (I) 750° F toxic gas at tri.fluoride and molten
450° F Alkaline metals.
Fiberglas 14WF 5SOO F Fair to Good Fair to Good Fair
Flltron (4) 5050 F 270° F Good to excellent. Good Good to Very Good
Softens
,,) Du Pont Reg. Tr.demark (2) Amarican Cyanamid Reg. Trademark
-Tamper.tures recommended by Industrial Gas Claenlng Instltula
(3) Union Cerblda Rag. Trademark
(4) W. W. Crlswall Tradenama
**W. W. Criswell Company, Division of Wheelabrator Corporation, 800 Industrial
Higheay, Riverton, New Jersey.
13
-------
......
>i:> Tj
P
0"'
'1
>-'0
n
'Tj
~
r>
'1
p
r>
>-'0
o
,::;
I
i
----
---- -
FIBERGLASS N2J
FIBERGLASS
N23
FIBERGLASS
N21
FIBERGLASS N2 3
REFLECTED
LIGHT
TRANSMITTED
LIGHT
20
x
MAGNIFICATION
Figure 1. 12
-------
~.f~,
~':~;
. ~;i:;
, '¥,
"
''If~
Y
I,
'" .
'.
" ~t
2";:~:' .,>1~
n'
~.:: .; I:~'
11f
, :'i{t~J:
,.: "if~ ,:'-'ri.
.' :~, "~ . 1.1.
,~>;:,'~ " " '"':Cl",',',','",",'"",,,'."i'.""""'. ,",.',' :~",;ft";Ji:,j,.,~'~
;f1~;it- . D';,
I,"
>"~' . ~:' ~ .~.
DACRON
''!;;1 ~,.:,ft
'~'t'>, !;'~."
: ~':'~.:'1f';:::'f
"r11f'" '---. '"
~.."... ti:ff};~tfr:"I~: \,:'~-
",",' ,.1"" "ij.:..., ,., ';.,,~ ,:~
-' " ~:,.:." -. ;'t:. \!i!t'ii~~~!..!'
: ":~~' ,!~t- >:'l': :,
." :.-':. .
',,t(" .
- "
-. '
c
"'
-,
.r;
A
DACRON
B
REFLECTED LIGHT
-- - -
DACRON
A
DACRON
B
TRANSMITTED
LIGHT
20 X MAGNIFICATION
Figure 1. 13
~
~
0"
'1
,.....
()
~
,.....
I-'
M"
'1
~
M"
,.....
o
;::s
-------
I-'
c;y,
FIBERGLASS
N21
DACRON
B
REFLECTED
LI GHT
20
x
I>
I~
(
p.
~
FIBERGLASS Ntl
DACRON
B
TRANSMITTED
LIGHT
MAGNIFICATION
Figure 1. 14
-------
Table 1. 3
CONSTRUCTIO~ DETAILS OF TEST FABRICS
Filter Fabric Fiberglass Dacron
2 ~o. 1 I :'10. 2 ! No. 3 A B
Air Permeabilitv (dm/ft. at 1/2" H20) 13.84 ! 11.67 i 7.86 28.06 114.62
2 I I I
Weight (oz./yd. ) 8.41 I 8.67 9.06 5.51 6.06
I I
I I
Yarn Count 55 x 50 I 55 x 54 55 x 58 82 x 62 82 x 76
Filament Diameter (in.) 0.00025 0.00113
Yarn Diameter (in.) 0.0097 --
Filaments Per Strand 408 50
Strands Per Yarn 2 1
Twists Per Inch 3.8 3.5
Weave 3/1 Crowfoot 3/1 Twill
Finish Silicone Oil Silicone Oil
'r1
po
0"
;:1.
l.>
'r1
.....
I-'
~
.,
~
..... .....
-oJ 0
;:J
-------
I,; 1,1';( :'l'I{OSTATIC I 'IU~C] PITi\TORS
W. I). Snow"('('ipt!:1f'o!' ('valved rrOn1
;lppl."ll1g .\11 (.!('l'tt'[('al :tpp,'o;.!('11 to gas dean-
mg. TI \t' (' 1 ('(' I r' (';d ;tpp\'o:)cil became feasible
II itlt 111<' .\ch enl or t<.'cll11ologiC'al advancements.
;t!JuJI(!ant ('kelt'ie power, and with the in-
lTeasing nt'f'd 10 controL minutp particulate
l' 111 i,.;" ions.
Flc,,'frosta!i(' pn'cipitato!'s ()pc~t'ate by
(' )'(':l( in!o': all ('[petri(' field between a negative
POI;II'lI\
-------
E10dl'ostatic Precipitators
---
'flh1..rro IN'" ,..nt!
....,r(8 n.N)Mlm.
..... & ....<..IfT
"""('TTW'I ..,.,.... '(
DafOH II""'"
...,""
UC'TI1CA1 ..c.n"'08
I
UJftI ~ID
I!lKftOOt 'fA""
uml 11 v CUIDf n.tuW.f
".V win I!lKftQOl
tllCTlO.MAGNfT1C lA''''
OUTIIDf ~OID
COUfCTtNC ItfCT'lOOf!
JC'I8H Gl'ID POIMINCi
POCI:n ON COUKnHG flKT1tOOf
AUliLiAn HOf'PfI "'~AMlm
W'AtCW'A'f . ..caB DOOI
M.Y. ""'" IUCftOOf
t..OWII"V GUrDI N.&.Mt
"W. WIll WttCK1'
Courtpsy of The Thermix Corporation
IOWa ".'11 0UIDt IIIA.tITII IUfI'fQtT
I,' igUl'(' 1.
1)ltY-TYPI'; 1~;Lfo:CTROSTATIC PRECIPITATOR
o
C
SQUARE
ROD
@
SPACED
DISCS
ROUND
ROD
BARB
I,'igurc 2. TYPICAL SIIAPES FOn
DISCHARGE F~LECTRODE
'J
J
- ----!
-------
Electrostatic Precipitators
,/
. . - ...- .. . .... . . . . ....- -. -._---- ----~--
DISCHARGE ELECTRODE
COLLECTION ELECTRODE
/' '"
~h<%;'ri0:,{':;'¥-W2t~~
!'JIP'~.~~Iia~/fffY~l1ftjmi~ %a1imimiii,,-
Q
.
.
.
..- D I SC_H AJ~ G E
ELECTRODE
~
~
~;,M;P1f'~;t#%$~,$f'.#.W(V'#%~~gp~~
(TOP VIEW)
(SIDE VIEW)
b.)HORIIONTAL
t t
Q
a.)VERTICAL
Figul'c ;1. COLLECTING ELECTRODE CLASSIFICATIONS
ir. ~r. ~( ~r. ~(,
If Jf Jf J[ Jr.!
)( )( 1( ~( )(
---
II
II
"1
II
II
II
!
Figure 4. TYPICAL COLLECTION
E I ,ECTRODE CONFIGURA TrONS
3
-------
Eh'ctrostatic Precipitators
c1tmosplterf':-i, and initial and maintenance
costs, TI1f' magnetic impulse rapper has
LJl'l'n nI1(' of tlte most wirJely accepted rapping
nwehanisms due to its ability to provide
dosl'l.'" eontl'ol]e<1 continuous rapping.
Tl1l' dr,v-t:vpc pl'l'cipitator may be subdivided
I11to two broad classes; one stage and two
stage. The on0 stage utilizes ionization and
col1f'ction of th(' particulates in a single step.
Tlw two stage precipitator has a pre-
ionization step followed by collection and is
lH'st suited rO!' heavy dust concentrations
(See I.'jgu\'(' ;,),
W;\slting is Iised in !II<' \Vc1-t:vPC' precipitator.
W;1I('I' is 1'('<1 thl'oug'lt l'alihratcd wier rings
at tIlt' top of tllP tube colledion electrode.
'\ V('!'\' thin eolledion film of water is
fO\'I1Il:cI whiclt ('nn 11(' elt-aned and recycled.
(,o]1edion ('[cc!I'od(' c1ean1inf~flfI and the use
of soft., e;:J,]I'iun1 fre(' water is a prime
('onsidcl'atiol1 in wpt-tYPt' prpcipitatol' opera-
tion (S('(' "igul'(' 6).
DIRECTION
OF flOW
: '
, :
,
,
, ,
,
, ' ,
, I ,
,
,
: '
,
, '
,
:
"-
COllECTOR
elECTRODE
t ~ ~
::; ~ COLLECTOR
~ ::: elECTRODES,
- 0
-11:\--- CORONA....::.....
~ WIRES -...::. . . t -+
CORONA
WIRE
A. SINGLE ST AGE
TUBE TYPE
B. SINGLE STAGE
PLATE TYPE
The washing procedure becomes necessary
in the dry-type precipitators when collecting
dusts that require an adhesive on the collec-
tion electrode. Washing of the electrode is
accomplished by a high velocity spray and
then applying an adhesive before putting the
unit back in operation.
Gas flow distribution should be controlled
before, within, and after the precipitator
chamber to maintain an even deposition of the
particulates in the chamber. Uneven buildup
of particulates results in higher gas velocities
and a lower effective voltage across the
electrodes. Both high gas velocities and a
lower voltage result in reduced precipitator
performance.
Gas flow dif.jtribution can be enhanced by
closely spaced guide vanes at the bends and
by diffusion screens or plates at the inlet
to the precipitator. The perforated inlet
plate serves to deflect and reduce turbulence
of the gas as it enters the precipitator. A
diffuser plate is defined in terms of solidity;
--
DIRECTION
OF FLOW
EARTHED t+'I
CYLINDERSY
-+
CORONA WIRE}£)
(POSITIVE) --0
CHARGING
SECTION
COllECTOR
ElECTRODES -- +
+
+
-+
+
PRECIPITATING.... ..
SECTION
C. TWO STAGE
Figure 5,
CLJ\SSIFICATIONS OF DRY-TYPE PRECIPITATORS
,I
-------
Electrostatic Precipitators
Higl1 Voltage Insulator Compartments
Sup;>a"'
l'I>ulatcrs -,
To Clean Gas Main
)
High Tension
Oi scha rge -1"-
Electrodes t;,
.' III!
Cell..,'!, ing
Electrode Pipes
She 11
Gas ','1 ec tor
'one
High Tenslon
Electrode
Electrode Weight
Effluent Out
igun' 6.
\VET-TYPE ELECTROSTATIC
PRECIPITATOR
a ::;o1idity of S 0.30 means the plate or
screen is 30a;! blocker! and 700/0 open.
The precipitator chamber is enclosed with
a round or rectangular shell depending upon
the type of collection electrode and material
cos ts. A round shell with a domed top is
most a.pplicable with the tube type collection
electrodes but also when the precipitator is
to be operated under pre::;surized conditions.
!\ rectangular shell is most suited to the
plate type collection electrodes.
TIll"' cost dt'lWnds upon the' type of building
material. The precipitator 8h('11 can be
made of steel, reinforced cone ['ete, rein-
forccd CO!HTl'te frame wilh brick or tile
walls, ur lt~ad lined for collection of cor-
rO>4ive paJ'ticulates.
The p!'ccipitator hopper is integral with the
precipitator shell and is made ~ro~ the same
materials. The hopper's functlOn IS to
collect the precipitated material for final
disposal.
A power supply to provide a r~1iable sO,urce
of high direct current voltage ~s esse~t~al for
the operation of an electrostatic preCipitator.
The power supply is normally 440 volt, 60
cycle alternating current which must be
rectified to direct current for use by the
electrostatic precipitator. A transformer
is used to increase the voltage followed by
a rectifier to convert the voltage from alter-
nating current to direct current. Mechanical
and electronic rectifiers are the two most
widely used in industrial applications.
Precipitator performance can be appreciably
increased by the use of bus sections. The
use of bus sections, or seperately energized
precipitator units at different voltages, is
referred to as sectionalization. The increased
efficiency must be evaluated by considering
the additional cost of separate voltage supplies.
The electrostatic precipitator units are
connected in both series and parallel (See
Figure 7).
Series sectionalization is the most important
and is necessary to uniformly collect the
particulates. With equal series voltages,
the particulates will tend to agglomerate on
the inlet unit as the gas traverses the pre-
cipitator units, This uneven buildup will
reduce the voltage across the first unit and
cause an increase in gas velocity, both of
which result in reduced precipitator per-
formance. To reduce upstream buildup,
downstream precipitator units are normally
activated at higher voltages.
Parallel sectionalization is normally used to
cope with uneven gas flow at the inlet to the
precipitator, Parallel sectionalization is
particularly useful to accommodate the large
gas flow associated with the center of the
inlet duct and with bends in the duct.
PARTICLE COLLECTION MECHANISMS
An electrical potential difference ranging
from 10 to 100 kilovolts but usually within 40
to 60 kilovolts is maintained between the
discharge and collection electrode to initiate
gas ionization. Gas ionization is the dis-
sociation of gas molecules into free ions.
The large voltage applied across the electrodes
breaks down the relatively non-conductive
gas which then begins to conduct an electric
current by ion migration.
As the gas passes between the electrodes,
the particulates are bombarded by the ions
migrating to the collection electrode thereby
acquiring the polarity of the discharge
electrode. The particulates are attracted
to the collection electrode as the two are at
unlike electrical charges.
5
-------
I~l~_t !.',)static- Pl'ecipitator's
,
I
I ---+- 7
I
, 82
'
,
,
/ ~
e3 e7 e) /
~I I I I '
,
1 1 1 '
I ~ f
I
I Q 8,
I
\
, ~
"
,
a,) SERIES SECTIONALIZA TlON "
, .. 7
(e):> e2:> 83) "
, 82
"
"
-
\
\
b,)PARALLEL SECTIONALIZATION
Figure 7.
TYPICAL ARRANGEMENTS FOR SEPERATELY
ENEltGIZEU PRECIPITATOR UNITS
'1'11,' padial dl'ctric bn~akrlown of the gas
sUl't'Otmding the discharge electrode forms
a visibl!' blue electric discharge ealled the
corona 01' coruna glow. An increase in
voltage beyunrl the corona voltage will result
in an infinite current being transmitted
between the electrodes in the form of an arc
01' sparkover (See Figure 8). Field investi-
gations have demonstrated that an optimum
sparkover rate exists at 100 sparks per
minute per precipitator section. (2)
Hesistivity is a term that describes the
rpsistance of a medium to the flow of an
electrical current. For ease of precipita-
tion, dust resistivity values can be classed
roughly into three groups:
Be]ow 5.0 X 103 ohm-cm
~
r~etlVl'eJ1 5.0 >< 103 ami 2.0 X 1010
ohm-em
:j
Abov£' 2.0 X 1 oj 0 ohm-em.
";It'ticubtcs in group 1 at'l' difficult to
CCll1f'ct. TIWnP particulatcs are easily
cliLlr'ged and precipitLd,ed but, upon contacting
th,' Colll'l'tion dl~ctrodL', lose thejr dinchLlt'ge
el('drod!' polarity and acquir!' the polarity
ur tlw collection dectrode. The partj(:ulates
are tlll'n I'epelled into till' ga::; stream to
G
either escape from the precipitator or
become recharged by the corona field.
Baffles are often designed on the collection
walls to limit this precipitation-repulsion
phenomena (See Figure 9),
Particulates with resistivities in group 3
cause back-ionization or back-corona which
is a localized discharge at the collection
electrode, due to the surface being coated
by a layer of nonconductive material. A
weak back corona will merely lower the
sparkover voltage, but a strong back corona
produces a positive ion discharge at the
electrode. Back corona phenomena becomes
severe with a bulk particle layer resistivity
greater than 1011 ohm-em.
Particulates with resistivities in group 2
have been shown by experiment to be the
most acceptable for electrostatic precipitation.
The particulates do not either rapidly lose
their charge on contact with the collection
electrode or cause back corona. Back
corona phenomena can be decreased by
treatment of the gas stream such as altering
the temperature, moisture content, or
chemical composition.
Partidf' resistivity decreases with both high
and low temperatures (See Figure 10). A
special high voltage conductivity apparatus
-------
Electrostatic Precipitators
...
,
SPARK-OVER'
\
t
I
I
I
I
I
I
I
I
I
I
I GOOD I
I ;ERFORMANC~ I
.....
Z
w
or::
or::
~
u
VOLTAGE-
I,'igu!'f' B. VOLTAGE AND CLJRHENT RELATIONSHIP BETWEEN
IJISCTIAReE AND COLLECTION ELECTRODES
HIGH VOLTAGE
/ DISCHARGE ELECTRODES '"
I?f\\ I?f\-\ ---
\ { I \ I (I I \ I
:m m
1/ I \ \ II \\
111\\" / III \\\
11,\\ I 1\
Q(GAS FLOW)
BAFFLE
I
.
I'if..,rur<' D. ('OJ ,) ,IWTION METHOD F'OR LOW RESISTIVITY MATERIALS
7
-------
!~~~ostaf. ~~r'e('i pitators
1013
V')
a:
w
r--
w
::;: 1012
1-
Z
uJ
W
I
Z 1011
:r:
u
>-
~-
'- 1010
,
(I)
l/'J
U'
CL 109
f-.,
,-
w
a:
«
a..
a.. 108
«
0 100 300 500 700
TEMPERATURE IN DEGREES FAHRENHEIT
Fiv,ure ] o. EFFl~:("l' OF TEMPEHATURE
I\ND MOTS1'TJTU: CONTENT ON APPARENT
rn:STSTIVITY OF l'HECIPTTATEI)
('EJVII';N'I' DUST
(',Ill lH' \lsl'd to dctprillinc !'rxt-:tivity values
,1t ('ontl'olkd t('mT)('ratl1re.
1'~\rti('I(' l1Iigration velocity or drift velocity
is dr'dslically affeded by particle resist.ivity.
I),'ift vt'locity is thl' speed at which the
('II,jf'Ic:,'r! parti('111at.e approH('hes the coll(~ction
cit'd r'''cI('. T ,ow resistivity or easily charged
pal'iiculo.tcs have a high drift velocity which
pr'ovi
-------
--------
Electrostatic Precipitators
20
15
I
I
I
I
I
I
I
I
I
GOOD PERFORMANCE I
v
Q)
~
'-
E
v
>- 10
!::
u
0
.....
...
>
...
...
'"
0
5
105
I
I
: POOR
PERFORMANCE
1010
1013
PRECIPITATED RESISTIVITY (ohm em)
1011
I,'il~llre 11. 1':VF1':Cr OF TYPICAL HIGH PARTICLE RESISTIVITY
(CJ.:MI':NT) DUST ON I'ImCll'ITATOR PERFORMANCE
f'recipitator pprformance increases with in-
creaseu collection plate area and decreases
with increased gas flow. Awareness of these
performance characteristics in the design of
a pilot plant has been shown to be an effective
approach to scientific precipitator design.
,\PPLlCATIONS OF ELECTROSTATIC
PRECIPITATORS
The ma,ior applications of the electrostatic
precIpitator arc found in industries such as:
1':Il'c:t ric I 'OWt'l'
Mt'tLlllul'f.~ic;d
(' {' III(' nt
1';qH'r Mill:J
( ",('mical
I),'t:trrtllg of FII{'I
('arbon IHal'k
(;;IS{'S
'1'111' l'oa)-firpc! el{'dri(' power industry now
g,'ncral.ps approximaL<'ly 75";', of the elpctric
power. TI1{' use of pulvf'rlzl'd coal as a fuel
yields minute fly ash particles with variable
quantities of sulfur and carbon. Both carbon
and sulfur affect resistivity so the content
of each must be monitored to achieve maximum
efficiency. Ultimate disposal of the collected
fly ash is a major problem. The ash has
been used as an additive in concrete, as
pressure grouting, and as an asphalt paving
additive.
The metallurgical industry, confronted with
legal suits against fume damage, has begun
to use the electrostatic precipitator to limit
fume emissions. Closed damper rapping
is often required to limit re-entrainment of
the collected material. In zinc roasting
applications, the collected material on the
discharge electrode clings to the electrode
and requires manual cleaning. The use of
electrostatic precipitators in the metallurgical
industry, in addition to reducing smoke and
fume emissions, resulted in the collection
of valuable copper, lead and zinc oxid£'s.
The cement industry uses the electrostatic
precipitator to efficiently reduce the large
9
-------
1':I('l'tl'()sf;lt il' l'I'('l'lpi(;lLol'S
--- ~ -----------
dus( <'IllI>";lons fL'O!11 l'otal'y-rlinkering kilns,
,.;11<1[(' ~llld ,.;L<)11l' dl'.\"e]',.;, and grinding opera-
1 J()Il";, I'al'llcll' I'l'sisti\'it,v is Q rritical
<'onsidel'aLlOn III prl'cipitating cement dusts
l1Pcausl' tlie l'al'1ic]e,.; ('miHed at the operating
tl'J1I1)("'~ltlll'l' (I)('(\\('('n ~oo and 700°F) are
dJl'i'I('lllj to pn'l'lpil;ltc unless the moisture
<'O!ltent i,..; IOn;, e'r lIlOI'C. 1 ftgh efficiency of
( ollel'( Ion makes the dectrostatie precipi-
t~\tOI' d favorahle ,~;IS l'leanlug method in the
l' (' III C 11 I. ill rill S t 1',\ ,
I ':lj)(' I' mill,..; U:-;(' the pJ'I'clpitator 1.0 recover
>:Li I. ('ake l'l'pm 1'('eov('r,v-furn,H'I' gases and
((J ~;I'IH'I'all.' 11!ll!L air' pollution. /\pproxi-
111;lfl'l\ ] ~)O pO\l11ds 0[' salt l'ak(' \)('1' ton of
pilip cal1 lw l'eco."I'J'!'d which \\Ias pr(,vlOusly
1''.:!)('lkrl Itlto 11)(' atnlo,,.;phere.
'1'11(' ('11!'tlll<'al indu";(I'y ,'mploys t'lectrostati('
I'!'('l'iplf:lfol's to colll'd valuable' aerosols,
I'kan g~ISl''''; 1'01' fUtLI!'(' pJ'OI'PSSl'S, and lo
111\111 ail' pollution. The most significant
US(' is I'ound in sulfuric acid pJants in elimin-
,Itiug :wld 111i,;ls and ,,.;ulrur oxide en1issions.
111 tll<' ~~:lsil'll'alio!1 or ()J'~~anic nwtt,t'ials it is
I1l'('('S,;;II'Y 10 I'Plll0V(' 1.1](' s])lall amounts of
[:11' 1)]'I'S('I1l. ThL' l'll'd)'ostatic pt'ecipitat.o!'
II:lS 111'1'11 r"l1l1d to 1)(' an efficient nleans 10
Ilt-I:,,' 111<' g;IS(''';.
'1'11,' ('1l't'1I'o,>;l;Jti(' PIT,'ipilJ'('('ll'il:,(o!' II;IS S('Vel'a]
",h',lld,lg",,,; ;!lII[ dis:ll!l':iJd;'gl',''; J'('I;i!ivI' lo
l)IIII'I' 1':11'1 i,'ul;II<' ('oll(TI(I!'s. 'I'IJ(' advDntagps
Illl [I[d,"
II i,I.:11 ('(1111'('1 j"l1 (,rfi(' jl'IWY 1)11 1'('!1HJV,j I
,>I' ";1111-llli('I'OIII"(I'lil'U!;ill'S (;IS l()w
,", 11,0\ Illi,'!'ul1)
'J
I,OIV o!)('!'afioll I'OStS
:)
I,ow ))J'('SSItl'l' drop thl'ough pt'ecipitator
(Iw[ow O. ~ in ":20)
4
Ikl:Jtlvely lal'ge gas flows can be
dredively handlr>d (to 2,000,000 cfm)
10
5
Can operatp precipitator under high
pressure or vacuum conditions (to 150
psi pressure)
6
Can use electrostatic precipitator under
corrosive particulate conditions
7
Removal of precipitator units from
operation for cleaning is unnecessary
8
High temperature gases can be handled
(to 12000F).
The disadvantages of the electrostatic pre-
cipitator include:
High initial cost
2
Large space required for installation
:3
Explosion hazard when collecting
combustible gases or particulates
4
07.on(' ()3) produced by a negatively
charged discharge electrode during
gas ionization
5
Complicated operation procedure which
involves precipitator adJustments for'
a
Gas flow distribution
b
Particulate resistivity values
c
Corona sparkover rate.
CONCLlTSION
The electrostatic precipitator is an electrical
approach to gas cleaning which utilizes
electrical charging of the particulates for
,'emoval from the gas stream. Variables
such as resistivity and si7.e of the particulates
and temperature and moisture content of the
gas arrect particulate charging and removal
"ates. Both the wet-type and dry-type pre-
l'ipilatonl are commonly used in industrial
-------
Electrostatic Precipitators
:1
Sen-Ichi Masuda, Toshio Onishi, Hiroshi
:--;:1110. Inlet (;a" Humidification System
tal' 1':lecl l'o"Lltic Precipitator. lndus-
11'i:d and Eng)lll'erin~ Chemistry Pro-
('I'",.; 1)1'"ign and l)p\'I'lopnH'nt, I\pril
\%11.
I:os(', Il. 1:., \\'ood, .'\. ,I, I\n Intt'oduction
(,) I :1t'ctl'ost:tt it- I'n'C'lpitalion in Theory
tllli I )1';\ C'tlC'l' , ConsLlhll' dnd Company
1.ld., 1.()nr1on, If):'6,
;)
\V iI II<' , II. .1. Clwmil'LtI :ltld Physical
1';1]'[1(,11' ( ondul'tlvit,Y Fal'tol's in
1':l,'ctl'l('al Precipitation. Chemical
Engineering Progrpss, ,June 1956.
G
Engl'lhrl'l'ht, Heinz 1" Electrostatic
PrecIpitators in Tltprmal Power
Stations Which Use Low Grade Coal.
.\ir Engineering, August 1966.
-,
Parkpr, 1'. R. Principles and Applications
01' E1I'l'lrostatic Precipitation. Chemical
,me! PrO('l''';" Fngllwering, Sept. 1963.
"
i\Ll11l1,,1 Out\lIlt' , 1'1\. C. pm, 77a.:'. 61.
9
Lagarias, J. S, Predicting Performance
of Electrostatic Precipitator. .Journal,
Air Pollution Control Association,
December 1963.
10
Aerotec Electrical Precipitator,
Aerotec Electrostatic Precipitators.
11
Katz, Jacob. Electrostatic Precipitator
Primer. Iron and Steel Engineer,
May 1964.
12
American Petroleum Institute, Division
of Refining. Removal of Particulate
Matter from Gaseous Wastes
Electrostatic Precipitators. An
Engineering Report Prepared for the
American Petroleum Institute by the
Chemical Engineering Department of
the University of Cincinnati.
13
Katz, Jacob. The Effective Collection
of Fly Ash at Pulverized Coal- Fired
Plants. Journal of the Air Pollution
Control Association, November 1965.
11
-------
Section Five
WE1"' COLLECTORS
All I\bout Wet Collectors
G:>avity Spray 'I'ow0r>
Impin~ement 'lyPe Scrubbing Tower
Collectors with Self-Induced Sprays
r1h-;1ntcr:rator :';crubbers
Wet Centr if'up;al Collectors
VI ~tltlU'i. :~crubh('r~~
-------
ITEM NO. 243
DUST CONTROL REPRINT NO. 270-P14
ALL
ABOUT
WET COLLECTORS
Uy (,011 ~ickie
[)ulfl Control PrOflut.ts
A ",nit'an Air Filter Co., Int'.
l,ouisvill,., Kentucky
m
American Air I=il..r
COMPANY, INC., LOUISVILLE, KENTUCKY
I'A. C. pm .10Y. 5. 73
Reprinted Courlesy 01 AIR ENGINEERING MogQzine
-------
ALL ABO UT
WET COLLECTORS
By Lou Dickie
Dust Control Products
American Air Filter Co., Inc.
Louisville, Ky.
EQUIPMENT which would loosely qualify as wet
collect0rs has been used for the treatment of
air for more than 100 years. Despite this
relatively long existence wet collectors are not well
understood by the average user. More confusion sur-
rounds the selection and application of wet collectors
than is experienced with dry mechanical, fabric, or
electrostatic type collectors.
Wet collectors have reached this unenviable
stat us for several reasons:
( 1 ) Wet collectors are commercially available
in many different designs. There are more various
wet collectors than there are differing devices in the
other three groups.
(~) Many designs have developed through trial
and error rather than the theoretical application of
collection principles.
(3) High energy devices, most widely used
today, where the pressure drop exceeds 4" W.G.
were not introduced until the 1930's.
(4) Prior to the 1950's little or no theoretical
studies were conducted on wet collectors except by
the manufacturers themselves.
P..inciplt's of (~ollection
An explanation of collection principles should
precede a discussion of collectors. Generally, six
principles are considered to be available to cause
collection of particulate matter. They are:
(1) Gravitational F'orce
(2) Centrifugal Force
(3) Inertial Impaction
(4) Direct Interception
(5) Diffusion (Brownian movement)
(6) EIl:'rtrosJ.atic Force
As stated, thes(' I1pply to the collection of particu-
late mntter and others, such as adsorption or absorp-
t ion, are required for collecting gases. This article Is
limited to wet collectors as used for collecting particu-
late matter.
Particles of sufficient size and density to be sus-
ceptible to gravitational force and settling represent
little difficulty for air cleaning. This well known
principle is the basis for settling chambers and is
generally limited to applications where the dust
exceeds 50 microns in size.
Centrif1('7al force is employed by both dry me-
chanical and wet collectors. Since centrifugal ac-
celeration easily produces forces greater than the
effect of gravity you can expect this mechanism to
provide a higher degree of separation than gravita-
tional force.
Inertial impaction is quite different from centrifu-
gal and gravitational force. As a moving air stream
approaches a target object in the stream, the gas
must diverge to pass around the object. The inertia
of dust particles carried by the air stream tend to
keep these particles on their original course provid-
ing the possibility of collision with target object.
(See Figure 1.) Because the trajectories of particle
centers can be calculated, it is possible to determine
theoretically the probability of collision. The target
object may be a water droplet or coated fibre as
found in many air filters.
Direct interception also depends on inertia and is
merely a secondary form of impaction. As stated
above, the trajectory of a particle center can be cal-
culated but even though the center may by-pass the
Figure 1:
~R
"'L.t'W
TARGET
08,JECT
OUST PARTIt:Lf
IN~RTIAL I,,",PACTIO..,
.--.. ----
TMG&T
OB.JIICr
~~ ~~~~f~=~:--_. ~==---
c.=-- ('\U8T PA~TICL.
OI~ECT 'Nfe"crPT'ON
~=
~R
"'"LOW
-- ---==-(}
IVI --- '- I "'!i!!fIl
,r v v
TARGET
OLl_CT
O,.FUSION
-------
target object a collision might occur since the parti-
cll' has finite size. (See Figure 1.) A collision occurs
du(' to direct interception if the dust particles center
misses the target object by some dimension less than
the particle's radius. Direct interception is therefore,
not a separate principle but only an extension of
inertial impaction. While 'fabric collectors employ
direct interception exclusively it is also a significant
mechanism of wet collectors.
Diff1tsion is another extension of the impaction
principle. Very small particles, sub-micron, sus-
pended in a gas stream have an individual oscillatory
motion known as Brownian movement. (Again, see
Figure 1.) Here, particle and target colIide as a re-
sul1 of relative motion within limited space. While
collision or impaction may be the result of either
inertia or Brownian movement, the results are the
same,
Inertial impaction, dirert interception and diffu-
sion arc significant principles employed by air filters
!lnd dust collectors. Due to their close relation these
three mechanisms wiJI be grouped and called Impac-
lion.
Thc mcehanism of elf!ctrostatic attraction is
widely applied through the use of electrostatic
precipitators. It has be('n suggcsted that. electrost.atic
effect can play some part in the performance of wet
collrctors. A small amount of inconclusive experi-
mentation has been conducted, but it is generally ac-
ceptE'd that this effect is unimport.ant. in regard t.o
wet collector efficiency.
Centrifugal force and impaction (Inertial, Direct
Interception, or Diffusion) are the instruments of
wet collectors. The many different wet collector de-
signs offer varied means for achieving impaction. A
major distinction in impaction methods is:
(1 ) Dust particle colIides wit h liquid droplets
introduced int.u air stream.
(~) D1H;t particle collides with liquid pool ad-
jan.nt to air stream or liquid film on a surface (such
as baffle) in t h(' air str1'8 m.
In order to make 11 distinction the first method
will be c8llE'd impaction and the latter impingement.
Impingemcnt will also be userl to describe the colli-
sion of a liquid droplet nnd some surface of the
('oll!'c\or. This distinction is mnde Lo facilitlltc sub-
se!) uen t HnIlIYf-1is.
Cnllf'4~1c1l' (:JU!.;Mificul ion Hi m4~n h
Most w!'l collt'cIor's employ 11 combinaU01I of cen-
trifugal for"!,, impaction, and irnping-!'ment which
makl's i IIdr classification difficult. The Hequenc(' In
which these mechanisms arc cmploy!'d is diverRe. For
I'xnmplc, one collector may utilize ceutrifugal forcl'
tu accelerate a dust particle to the periphery of the
('ollector whl'r!' the partiele is impinged upon a
wetted surface to prevent its reentrainment. Another
collector might first expose dust particks to air-borne
liquid dr'oplets for impaction and then use centrifugal
force and imping!'mC'nt to remove the droplets from
thl' ail' strpam.
It is frequent that a wet dUHt collector will have
st ng!'s or sectio!ls per'forming different functions.
Fir::!t W0U!'j bc the conditioning s('ction followed by
a collecting or separating. section. Impaction is the
normal mechanism of the conditioning section. Here,
a relatively small dust particle collides with a rela-
tively large liquid droplet. The liquid droplet which
now contains one or more dust particles is of suffi-
cient size and density to be removed by centrifugal
force or impingement in the separating selection. In
this case, and with most wet colTectors, the purpose of
the liquid is to artificiaITy increase the size of the
contaminant to the point where it can be effectively
removed from the gas stream. In other collectors
the primary mechanism is centrifugal force exerted
on the unconditioned particle to cause impingement
on a liquid film which redw;es reentrainment of the
particle into the air stream.
Wet Collectors vs, Dry Collectors
It should be a x:easonable assumption from the
above that wet collectors are inherently more effi-
cient than dry mechanical collectors. How in general
do wet collectors compare with the other major
types in regard to collection efficiency? Figure 2
shows relative collection efficiency of the four major
t.ypes of collectors.
-
Figure 2:
-~ ~_f"'," ~"'IU.C~ - 'l~t_~N_"'~f:.~~
I
-~ ------J
Wet collectors themselves show a wide range of
performance. This variance is not attributed to the
type of design or the competence of the designer and
fabricator. In the last 15 years several investigators
have attempted to define the parameters of cleaning
efficiency for wet collectors. As a result it is gen-
erally accepted that-for well designed equipment the
efficiency dcpends on the energy input per cfm of all'
only, find Is independent of collector design. Efficiency
is 11 funcUon of total energy input per cfm,
whether the energy is supplied to the air or the
water'. Now, tc be well designed the energy should
be expended in the area of gas-liquid contacting
process, Well-designed collectors by different manu-
facturers with equivalent power requirements will
demonstrate comparable efficiencies.
Wet Collector Types
As previously stated it is difficult to classify wet
collectors. Nearly every text will use different termi-
nology and a different number of classifications. The
following categories are offered as a compromise:
(1) Chamber or Spray Tower
(2) Centrifugal
(3) Dynamic
( 4 ) Packed Tower
-------
(5) Atomizing-inertial
(6) Atomizing-mechanical
No significance is intended by the order in which
these classes are listed. Many collectors could con-
ceivably be listed in more than one of the above
divisions. In this case the intention is to categorize
on the basis of the most dominant characteristic.
Chamber or Spray Tower collectors consist of a
round or rectangular chamber into which water is
introduced via spray nozzles. (See Figure 3.) There
are many variations of design, but the principal
mechanism is impaction of dust particles on the
liquid droplets created by the nozzles. These droplets
are separated from the air stream by centrifugal
force or impingement on water eliminators. Water
eliminators frequently take the form of "V" shaped
baflles.
--
Figure 3:
A
B
Clean Air Outlet
Spray Nozzle
Headers
Dirty Air Inlet
Water and Sludge
Drain
Supply Water
Piping
C
D
E
SPRA Y TOWER
Pressure drop is relatively low, on the order of
%" to 1Yz" W.G., but water pressure ranges from
10 to 400 psi. Collection efficiency is the function of
water pressure with all other parameters being equal.
The high pressure devices are the exception rather
than the rule. In general this type of collector is con-
sidered a low pressure instrument operating in the
lower efficiency range of wet collectors.
For conventional equipment, water requirements
are reasonable with the maximum being about 5 gals.
per 1,000 cu ft of gas. Those devices using high water
pressure, frequently called fogging type, may require
as much as 10 gals. per 1,000 cu ft of gas.
Wet' Centrifugal collectors comprise a large por-
tion of the commercially available collectors. (See
Figures 4 and 4A.)
This type utilizes centrifugal force to accelerate
the dust particle and impinge it upon a wetted collec-
tor surface.
Water rates are usually 2-5 gals. per 1,000 cu ft of
gas cleaned. Water distribution can be from nozzles,.
gravity flow or induced water pickup.
Pressure drop is on the order of 2 to 6" H20.
As a group, these collectors are more efficient
than the chamber type. Some, similar to equipment
in Figure 4, are available with different numbers
of impingement sections. Fewer sections offer lower
efficiency, lower cost, less pressure drop, and smaller
space requirements. Others, as in Figure 4A, contain
multiple collecting tubes. These relatively small tubes
provide higher collection efficiency in the s~me man-
ner as multi-tube small diameter cyclones are more
efficient than large diameter cyclones of the dry me-
chanical group.
Figure 4:
Symbol' Ports
A C"'an 011 (HJ"~'
8 En"al1lm~nl Stp%lor.
C WolnIflJ~/
o Implfl~m""l plolU
E 01(1)' Otrtfl/~/,
F 8W c~ for '011«1"9 hM7
mQ/~/1(J/
C Ift7f~ ond sludg. dfOllt
The Dynamic category is relatively small in that
there are few different types manufactured. How-
ever, there are many of these in service. These col-
lectors serve as air movers, thereby providing the
advantage of compactness. (See Figm:e 5.)
Spray nozzles at the inlet offer an opportunity for
impaction. Liquid droplets from the nozzles and un-
captured dust must pass through the many specially
shaped blades of the rotating fan wheel. Centrifugal
force and impingement on the blades is utilized for
further collection and water separation. Slurry is re-
moved and discharged separately from the cleaned
Hir.
Figure 4A:
WET
CENTRIFUGAL
COLLECTOR
Water requirements range from % to 1% gals.
per 1,000 cu ft of gas with required pressure being
35 to 60 psi.
The collector has no internal pressure loss, but
its mechanical efficiency is considerably lower than
-------
conventional exhausters. This low blower efficiency
puts it in the power requirement area of a 6" W.G.
pressure drop collector. Collection efficiency is com-
parable to other collectors with a 6" pressure drop.
Packed towers, see Figure 6, are not generally
used for the collection of particulate matter and are
occasionally not classified 'as wet collectors. Their
normal applications involve gas, vapor and mist re-
moval.
Packing material can be any irregularly shaped
objects which resist corrosion. Gas and vapor re-
moval is accomplished by absorption which is not a
mechanism for particulate collection. Frequently
vapors are collected by condensation and then im-
pingement of the condensed droplet.
Figure 5:
(JfrlyOlr
Ihl,f.
-=>
If'ET. TYPE OYNAMIC PRECIPITATOR
-,-
~.0tU1I.'.
$"'':.-:,~''''--
-~ =-..::
P~CI((D rOlffER
Figure 6: Illustrated above are two typical Packed
Towers normally used for gas, vapor and mist removal.
Conventional tower on left, high velocity design on the
right.
The high velocity acid mist collector is a form of
packed tower. As suggested by the name its primary
function is acid mist collection. As acid mist is in
the form of minute droplets, it is more similar to
particulate matter than gas or vapor and is collected
by impingement in the polyethylene knitted mesh
pads used instead of packing.
Pressure drop through standard packed towers is
from 1%" to 3%" W.G. for a 4 ft thick bed with
gas velocities of 100 to 300 fpm. Water flow is usually
downward by gravity at rates of 5 to 10 gals. per
1,000 cu ft of gas.
For the high velocity design, pressure drop is
3Yz" to 4" W.G. per stage with gas velocities in the
700 to 800 fpm range. Water requirements are only
Yz to 1 gpm.
These collectors will capture particulate matter
but are not used because dust will plug the packing
or pads. Unreasonable maintenance is required when
this type collector is used for the collection of par-
ticulate matter.
The Atomizing-Inertial category represents the
largest grouping of commercial dust collectors.
Available designs vary more widely than in any
other category. The size of this group justifies further
breakdown.
Atomizing Inertial
( 1 ) 1m paction
( a) Orfice
(b) Venturi
(2) Impingement
The Atomizing-Inertial-Impaction types utilize
kinetic energy of the gas stream to fragment or
atomize a liquid on which to impact the dust parti-
cles.
A major sub-group is the Orfice type collector
shown in Figure 7. The gas stream comes into con-
tact with a pool of liquid at the entrance to a con-
striction. Liquid is picked up and carried into the re-
TYPICAL WET
ORIFICE TYPE COLLECTOfl
Figure 7:
-- --
__I
stricti on where greater liquid-particulate interaction
occurs resulting in high frequency impaction. Upon
leaving the restriction most water droplets, those
large enough, are separated by gravity since gas
velocity is reduced from what it was in the restric-
-------
tion. Smaller droplets are subsequently removed by
centrifugal force and impingement. Water volume in
motion through the restriction ranges from 10-40
gals. per 1,000 cu it of gas. Most of this water is
recirculated from the pool and this volume does not
represent the collector's water requirements, which
may be as low as V2 gal. per 1,000 cu it of gas.
Pressure drop for the orfice type will range from
3" to 6" or more.
The 11 enturi, see Figure 8, uses a venturi-shaped
constriction and throat velocities considerably higher
than those experienced with the orfice type. Gas
velocities through Venturi throats may range from
12,000 to 24,000 fpm. Liquid is supplied at or ahead
of the throat through piping or jets.
Liquid rates will range from 5 to 15 gals. per
1,000 cu it of gas.
The Venturi itself is only a gas conditioner and
must be followed by a separating section for the
elimination of entrained droplets as shown in Figure
9.
The collection mechanism of the Venturi is im-
paction. As with wet collectors in general, the col-
lection efficiency of the Venturi increases with higher
pressure drops. Different pressure drops are achieved
by designing for varied gas velocities in the throat.
Some Venturi collectors are manufactured with ad-
justable throats allowin;; a range of pressure drops
for a given air volume. Systems are available with
throat pressure drops as low as 5" and as high as
100" W.G.
Gas volumes and pressure drops are limited only
Figure 8:
-- - --
by the capacities of available fans or pressure blow-
ers. Collection efficiency of the Venturi group can be
considered highest of wet collectors as it is ~lOrmally
operated and justifiable only at higher pressure drops.
--
8
G
VEN TURf SCRUBBER
Figure 9: Symbols-A Clean air outlet; B Entrainment
separator; C Water inlet; E Dirty air inlet; G Water
and sludge drain.
The Atomizing-Inertial-Impingement type col-
lector utilizes either a perforated plate with an
impingement baffle over each perforation or a tray.
)f glass marbles, as in Figure 10. Here the inten-
tion is to expand the surface area of the liquid
through use of the gas stream's kinetic energy. As
with the inertial impaction collectors, a separating
section is required following the conditioning section.
Efficiency, water rate, and pressure drop of the
impingement types are comparable to the orfice type.
The final category is Atomizing-Mechanical. In
these collectors a mechanical device, such as a rotary
paddle wheel or cage, is used to fragment and atom-
ize the liquid as in Figure 11.
The dirty gas stream passes througn that area of
the collector containing the mechanically produced
droplets and impaction occurs. Again, a water elimi-
nating section is required.
Water requirements are similar to those for the
orfice type collector.
Pressure drop is relatively low and in the 2" to
3~/2" W.G. range. However, considerable power is re-
quired for the mechanical atomizing device. These
collectors should be compared to others on a basis
of total power input and it will be found that collec-
tion efficie,ncy is comparable for equivalent power
requirements.
Figure 10:
wmROROPlET\
FOR~EO'T £06E5J CONT,JlLEO
.={ = WATER LEVEL
P/,;a ~~':~<'aiJ ~).
I I ~
GAS FLOW
ORIFICE PLATE
AIIl SUB8LE;
TURBULENT
--.i-.'-~l.\VlROf
. . ~:a.e C> WATER
o O,,'I'!.
t. t. ~:~ .t.-
I I
GAS FlOW
IMPINGEMENT 8AFflE TYPE
MARBLE TRAY TYPE
ATOMIZING INERTIAL IMPINGEMENT
-------
Why Wet Collection?
Figure 12 shows the relative cost of different
major types of collectors such as Dry Mechanical,
Fabric, Electrostatic, and Wet. Only dry mechanical
collectors are less expensive than wet collectors.
Fabric collectors of intermit,tent design-not for con-
tinuous operation-are in the same price range.
Fabric collectors for' continuous duty (as are wet
collectors) and electrostatics are more expensive. This
Figure 11:
chart does not include the Venturi at high pressurE'
drops which may cost as much or more than continu-
ous-fabric and electrostatics.
In addition to price advantage, wet collectors re-
quire considerably Jess space and installation than do
fabric or electrostatic collectors.
Where should wet collectors be used? Following
are some conditions which indicate and even dictate
the use of wet collectors.
(1) When collection efficiency requirements ex-
ceed the the ability of dry mechanicals but are within
the capability of low power wet collectors, wet collec-
tors are chosen on the basis of cost and performance.
(2) The nat\! re of the gas stream may pre-
cludethe use of other types or create the need for
expensive controls or accessories if used. These con-
ditions are temperature and humidity. Fabric collec-
tors are usually limited to gas temperatures of 550°F
or less. Condensation, associated with high humidity,
presents serious problems for all dust collectors ex-
cept wet collectors.
(3) Some dusts represent explosion or fire
hazards when dry, and wet collectors eliminate or at
least reduce the hazard.
(4) Water may offer a more convenient method
of disposal of collected material as it prevents the
creation of a secondary dust hazard where material is
handled dry. Frequently, collected material in the
form of slurry can be returned to the process more
easily than dry dust.
Figure 12:
1,.25 "''''''j''CO...'.'uo.'duIY~'I,'' :' ;1111.1; I ~ Ii.:
(Nola ',J) . . ; . : J! j ) ii'
100-- --+--- --- , ~
5,cllolll11 (o/)r;c I . : ' , ,
cO~'::,~:~$)~~! i:
~' ~~::i'icli ~:,,_. "_n . _:.. ."'.--~
, 0_...' ""'D9" 11"«1/)/10""'"
~ ~ - --...... ~.",--. -.. No,." 4
': -.......'................... ---'--'--'~Fobnc~,/r)rs I
I' ',,~-:::-.:-.-=_:.:-==-.~~-=.:..-!.!.:~~- f
.25- ; ., ,..." -""'-":~-;/IVIIHfICI.,,c;tCMIfri'UVO/J~
LQ.pr"'II'~drop~------____~!....No.!!!!. : I
a~D'" ',2) , : ,
" ,,2 2 i3 g g g g g 2 8 i3 i3 g 2 "" 2 g g
~",)"'''o(t;l<::> C)t)coC)C:I C)C)<:)C\<:::a<::> C)ggC)~~
- ...,."..!; ~~~~~~ ~~~~~~
'IN
COST ESTIMATES OF OUST COLLECTING EOUIPMENT
AS SHIPPED BY THE MANUFACTURER
Note 1: Where collectors are normally furnished
without exhausters, $.07/cfm has been added for ex-
h a usters.
Note 2: Where collectors are normally furnished
without dust storage hoppers, $.03/cfm has been added
for dust storage hoppers.
Note 3: Price of collectors in the group could be
more accurately estimated on the basis of number of
square feet of media for fabric arrestors, as there are
wide variations for a given exhaust volume, dependent
on the application. Estimates assume flow rates of 3 fpm
through fabric arrestors and 15 fpm through reverse
jet designs.
. Note 4: Price. of electrostatic precipitators will vary
with the contact time and the electrical equipment re-
quired. Prices shown are for fly ash installations when
high velocities of 300 to 600 fpm are usual. Precipitators
for metallurgical fumes, etc., will be considerably higher
I n cost per cfm.
There are other, more subtle, factors that may
indicate the selection of wet collectors for any par-
ticular application depending on operating procedures
or local conditions. However, in these cases a com-
plete analysis of wet collectors versus other types
may be required prior to determination.
Wet Collectors and Humidity
Wet collectors have one distinct characteristic not
found in other collectors, which is their inherent
ability to humidify. Humidification, the process of
adding water vapor to the air stream through evap-
oration, may be either advantageous or disadvanta-
geous depending on the situation. Where the initial
air stream is at an elevated temperature and not
saturated, the process of evaporation reduces the tem-
. perature and the volume of the gas stream leaving
the collector. Assuming the fan is to be selected for
-------
operation beh ind or on the clean air side of the col-
(t'etOl' it mny ue smallt'r and will definitely require
less powt'r than if then~ had becn no cooling through
the collector, This is one of the obvious advantages
of humidification. Disadvantages are associated with
the higher dew point and increased probability of
condensation if the a~r is to be returned to the work
area, The seriousness of this problem depends on
paramf'ters such as air volume handled by collector,
degree of humidifica!.io:l, volume of work area, and
:1m bien I condi tions.
The lIser should be aware of humidification and
should ('<1T1sidrr its !'ffects before Jinali7.ing design of
lilt' .'Ilti!'(' >'IYR1em, While nil wet ('oHectors humidify,
(ll(' :llIwnnl or hnmidilicnliOII vnl'ieH between designs.
Mesl 11\:lllnr:II'lnl'l'I"S I'nhlish tht' hllmidifyinl-( efH-
ci.'nt'y for tllt'il' l'qnipmenl and will :lRsi!:Jt in evnlnat-
illg 111<' L'lTect >'I,
Wltic'J. \VC'I (~ullC'dnr'!
What is the critcria for sdecLing :In individual
IVd collector from the m:lny !1esigns avnilable? Therc
arc 7 major considerations:
(1) DI'(/)"I'I' oJ collf'cti.orl required. It has already
been shown that wt't collectorR drmonst rate a wide
range of dlicit'ncies. Figure 13 shows the coller!.ion
efficiency of three different wet collectors, This chart
:lssumcs a collector prcssure drop reflecting an orfice
lype opemting <1t 6" W.G, and a wct
-------
disposal as slurry or recirculation. In a recirculation
system either of the above methods may be used to
clean out the settling pond or clarification equip-
ment.
Here again the final decision is one of economics
and local conditions. Many collectors are available in
modified arrangements offering a choice of disposal
methods.
(5) Materials of Construction. Water and air
alone will produce corrosion in the form of rust.
Frequently there will be contaminants in the gas
stream which, when combined with water, form
~wvcrely corrosive agents.
Wet collectors can be fabricated from mild steel,
stainless stl'eJ, and ('ven fiber-glass reinforced plas-
I ics. Collect ors fabricated of mild steel can be lined
with any number of protective coatings including
PVC and rubber. The necessary materials are avail-
nbll' 10 pl'Ovide adequate corrosion resistance for any
application.
Abrasiun alune is not a significant factor in wet
colll'ctors. The film of water which coats collector
sllrfaee nctllally fonns an abrasion barrier. Applica-
tions on l'xtremely abrasive dust such as taconite,
conal't(' aggregate, and sand support this observa-
tiun. However, abrasive materials in conjunction
with corrosion will appreciably shorten collector life
without proper safeguards. Corrosion is represented
by sealing or pitting of the metal surface and this
protects the metal below it from further corrosion.
SincE' (hl' snrface scale is irregular, it is susceptible
(0 abrasive erosion. As the scale or protective layer
i:-; rE'movl'd, the exposed metal is subjected to further
corrosion and the cye1e repeats.
Still, the initial problem is corrosion which can
hl' prevpn(('d through the use of corrosion resistant
materials.
(6) lIlninlcnan(:r. Maintenance requirements rep-
resent a most important consideration. Wet collector
main t l'IlU tH.t~ is at best a dirty business as the equip-
ml'lIt '8 lHtrpo,.. is to collect dust. Dust collectors are
lint nonnully considered production equipment and do
lIot rt.(,..iv(' the same attention Ilnd preventive main-
1 ('nllllt'l',
Malflllll'lions of till' culledor nunnally display one
OJ' mon° of the followin~ symptoms:
(II ) 1~lIild-np of dust within the collector.
(II) Water aud dust entrainment and carry-over
mto the t'xhauster, res(lltin~ in build up on the fan
wheel and imbalance,
(l') Mechanical.failures.
Build-up within the collector results from: ex-
cessive dll!~t loads. insulIkipnt water supply, poor
distribul ion of water within the collector, recircu-
lation of "xl rpmely dirty water, and poor drainage
:-;ystems or incorre<:tly trapped drains.
Where dust loads ar(' high, it is good practice
to preced.. the wet colll'd.or with a dry centrifugal
type. Th is pre(']caue/', wh i('Ir is inherently capable
of hight'r dust loads. will reduce maintenance and
('xll'lId tht' IISl'f1l1 life of thl' wet collector.
IlIslllIici,'nt Slll'ply wall'l' is the' ('ons('(lllene" of
water pressure loss at the inlet, or plugging of in-
ternal piping. A flow switch should be employed to
ensure against operation without sufficient water.
On water recirculation systems, spray nozzles should
be avoided as they are easily plugged.
If the collector is properly designed, water dis-
tribution will be correct initially. Failure to level the
equipment at installation may affect the distribution.
Again, nozzles may present a problem since their
spray pattern is altered as the nozzle wears.
Recirculating systems and drains should receive
thorough consideration at the same time the collector
is being selected. These items are frequently handled
as an afterthought and are inadequate.
Water and dust entrainment may result from
build up on the water eliminators and incorrect air
volume. Water eliminating devices should be kept
simple and accessible. Eliminator baffles which are
hard to reach will not be cleaned.
Periodic checks should be made to ensure that
the collector is handling the design air volume.
Mechanical failures can best be avoided during
initial selection of the collector. Look for simplicity of
design and the minimum number of moving parts.
(7) Dependability. Investigate collector perfonn-
ance on applications similar to the one in question.
Collector manufacturers keep records of installations
by individual applications. These jobs can be visited
to determine first hand the performance of a collec-
tor.
A Satisfactory Application
Satisfaction after installation is the objective of
an investigation prior to selection. Unexpected occur-
rences are too frequently unpleasant, and for this
reason, a prospective user is obligated to learn as
much as possible about thc equipment prior to pur-
chase. He should be intimately aware of its capa-
bilities and shortcomings and keep in mind the rea-
sons for selecting one design over another.
Wet collectors arc widely used, and there are
many applications where they are best suited. It be-
hooves us aU to bepome as well acquainted with wet
collectors IlS with dry mechanical, fabric or electro-
stat.ic tYPl'S. Without an understanding of wet col-
lect(l/'8, no vent.ilation engineer is complete.
~ince a coliector is only part of the system
which includes hood, ductwork, fan and supply
water piping, its performance is affected by these
components. The performance of any collector, then,
will be only as good as the engineer who designed
the system. ........
Picture and Diagrams Credits: Figures 2, 4, 5, 6 left, 7,
9, and 12, "I ndustrial Ventilation," American Conference
of Governmental Industrial Hygienists; Figures 1, 3, 4A,
6 right, 8, 10, and 13, American All' Filter Co., Inc.;
Figure 11, Centri-Spray Corporation.
-------
THE GRAVITY SPRAY TOWER
IMPINGEMENT OF GRAVITATIONAL
SPRAY DROPS
A In a gravitational spray unit, there are a
number of liquid spherical obstacles
(droplets) falling in an empty tower by
the action of gravity in the path of rising
particles.
R '1'11<' relationship between_imbingement
tar get efficiency (TJI) and og l is
shown in Figure 1. ~vpl 0 fp(stJ
in gravitational spray towers,
Vp/o
- -
is the difference in the free-falling
vl'!o('itiPs (Stokes') of the droplets and
I.h(' pa rtiele.
2
In pral'tice, sinct. the frce-falling
vf'locity of the particl~ is s_mall com-
p:1rt'U to th(' droplet, I vpl 0 may be
taken as the frf>c-falling velocity of the
droplf't.
C From Figure 1, it is evident that for high
collection efficiency by impingement
there must b{' a small ob_stac~ (Do) and
a high re tative vdocity !.vp/o_1 between
the obstarh' and particle.
In gravitational spray towers, these
l"omlitiolls tend to be muLually in-
compatibk. (Small droplets have
small free-falling velocities)
~~ Tlwr"eforp, there is an optirnum drop-
Id size (for :1 given particle size) for
Ll1axill1ulI1 impingcm£'nt targd efficiency.
(St.t. Figure 2. )
a Inspection of Figure 2 shows that as
rlropld size diminishes to the range
;)00 - 10001-1, the target efficiency
increases. However, a further de-
crease in droplet size, decreases
the impingement target efficiency.
PA. C. pm. 74a. !i. 01
b It is seen that the maximum efficiency
for the smaller particle sizes (say
less than 51-1) occurs for dropl~t size
of about 8001-1: and that for larger
particle sizes, the efficiency varies
little over the range of droplet sizes
500 to 1000fL.
Thus in gravitational spray towers,
there is little point in using very
fine spray sizes even if such were
available.
II
EFFICIENCY
A Inspection of Figure 2 shows that the ef-
ficiency of a gravitational spray tower is
very low for particles below 1 - 2 microns.
B Figure 3 illustrates a size-efficiency curve
for a large industrial spray tower handling
70,000 cfm. The tower is 22 ft in diameter,
66 ft high. Pressure drop is less than
1" water.
III
DUST CONCENTRA TIONS
A There are no fine clearances for the pas-
sage of dust-laden gases. Therefore,
it can handle relatively high dust con-
centrations without fear of chokage.
IV
GAS VOLUME
A It is capable of handling large quantities
of gas.
B It is often used as a pre-cooler where
large quantities of gas are involved (as
in blast furnaces).
V
RECIRCULATION OF WATER
A Since very fine droplets are not employed,
the spray generators need not have fine
jets.
1
-------
N
20
\
\
\
, \ T)r (spheres) = 0
\ ~
, \ at D g
0 = 24
'\. v f
, , p/o pes)
" '
." T)r (cylinders) = 0
, at Dog
,," ., - = 16'
~ '" '..... ~ v f
D " j r" ." p/o pes) -
....
-- .... "- ~... -.. I I I I
-- - - I. I I I I
0 2 .. 8 4 ~ 2
6
100
80
".......
~
c:
Q)
u 60
...
CJ
p..
'-'
H
C -'0
D g
o
vf
p/o pes)
Figure 1.
-------
.....
c:
Q)
u
~
Q)
0..
..
»
u
c: 10
Q)
.~
u
.~
'to-
C+-
Q)
+J
Q)
en
~
to
I-
100
1
10
100
Diameter of water droplet, microns
1000
10,000
Relation between collection efficiency and droplet size for a gravitational spray tower
Figure 2.
-------
The Gravity Spray 'l. '.\ '
c,
o
f--'
f-"
'"
(,
rJ
t...>.
()
;.J
~.--
tI'
.( 8 16 2 .( 8 32 ~6 ..C
100
t11
'",
'"
'"
n
.....
(1)
;:J
(,
,<
80
60
'U
(t,
.,
n
(1)
;:J
rt
.(()
20
o
Particle Size, Microns
Size-efficiency Curve for Spray Tower
Figure 3
-------
. "------- -- ------.----.
H<,nCL', the dirty water may be re-
cirl'ulated until it contains quite a high
l'onl'entration of trapped dust particles.
a
Therefore, there is a saving of
wa te r, and per hap s a s implifica tion
of effluent treatment and ultimate
waste disposal.
VJ
PRESSURE DROP
.\ The pn'SSUI'e drop is vcry small (less
than 1 in. w.g.)
V1J
PERFORMANCE DATA
(;as flow---------------ov{~r 70,000 cfm
C;as t('!l!perature
-------often used as pre-
cooler. Gas tem-
perature over 20000F
may be reduced to
:.!7fjoF.
(;:lti \"(.tacit)' -----------about :3-5 fpH
"'I'l'alnlt'l1t time --------dern Gas-Cleaning Equip-
ment. Paper read before the A. Inst.
P. London. November, 1955.
5
-------
IMPINGEMENT TYPE SCRUBBING TOWER
I
TYPFS OF SCRUBBING TOWERS
A There are two types of scrubbing towers
commDnly used:
Those employing impingement target
pIa tp s
~ ThacH' employing beds of spherical
obe;l,a des
TI
TOWFH WITII TARGET PLATES (Figl1rl' 1)
!\ ('oBstruction :1lld 0pcT'ation
This typl' of 51' rubhe r is a towpr con-
sisting of :1 vcrUci'1l shdl in which arf'
tn'_mnted a large nUlTlb"r of equally
SP3l'('d, circular, pl'rforatl'd (orifice)
pIa tes.
a At one side of l'aeh orifice plate, a
conduit, called a downspout, is pro-
vidpd to pass the liquid to the plate
below,
bAt the opposite side of the orifice
p]atl~, a simil8r conduit feeds liquid
fl'()JI1 ll1(' pl8h' above.
~
Ov('1' ,'aeh holt' (about 3/1£;" diameter)
ill 1.11<' orificl' plate, a target platE' is
positjolll'd.
a Tin' nlotiol1 Df tlH' gas past the edge
of t1w half's in th\' orifice plate re-
sults in tlw formation of spray drop-
Ids (:1hout lOOfJ-). Th<~se droplf'ls
arc iniLially at r<'st and provide an
effective l'l'lativp velocity betwecn
parth-le and droplet fur good
impingempnt.
b The particle-laden gas passes through
the holes in the plate and the particles
impinge upon the atomized droplets
and on the target plates.
PI\. C. pm. 73. D. GO
B Particle Concentration
An important feature of this design is
freedom from chokage in spite of the
small holes in the orifice plates. This
is due to:
a The very violent circulation induced
below the targets by the air jets,
and
b A preliminary spray zone which
helps to keep the orifice plate free
from deposits.
2
Concentrations of 40 grainsl ft3 can
readily ht! handled.
C Efficiency
1 An example of a size-efficiency curve
is shown in Figure 2.
D Pressure Drop
1
Each plate imposes a pressure drop of
3 in. w. g.
III
TOWERS WITH BEDS OF SPHERES
A Construction and Operation
(An example of a scrubbing tower with
beds of spheres is shown in Figure 3)
1
Large particles are removed by im-
pingement on wet surfaces and contact
with water spray in an area below the
filter bed.
2
Particle-laden gas then passes upward
through a bed of spheres. In the inter-
stices of the bed, the particles are
subjected to increased velocities which
results in their efficient impingement
upon the surfaces of the spheres.
1
-------
111~')~1~g(~ ))],-,~t~TYI2(~ ~(Tubbing Tower
-----
/~._-----~
/' 0 I3 0'
J 0
o
nJ 0.,." C~-~Ll 0
I dl'qet " " .L ,
"'" '.
'- "'----------....----------
~
\,~-~~.~ ~[',~Jc~~-- ~~~~~.
; ~ 11.1, ~ ,I, r t'::~'JF ~:~~"~'.:~S] J~ '.:
(~as f1 (J\'I
!\fJIU\rJI',! MI ~.JI 1'[' "11111(;11 1'11\11 :,"
IN IMf'INCr.MINr SCRlIBl\EI\
/,~ :-
,," '
IMP;NGt MfNT
eA,FFlE "TAGE
"GGlOMfQArl~C,
s' 01 ~,rAGI
I ' ,
1\'.
I; ...
tt
~
~~
- "-
",' ""'....
"
" ~ft~":;"~ \
( .000 0.0 \
(, - 'i~-. ./)
\~ h~, "
''''-- i?&i',\i ,f
"~""'=-~~~.>" ~
Water droplets atomized
at the edges of orifices
Downspout to
lower stage
MECHANISM OF IMPINGEMENT SCRUBBER
I','ahody ";ngmccring Corp,
I"i g" r(~ I
-------
100
~
s:::
(])
u
So.
(])
c..
80
~
s:::
(])
'r-
U
'r-
If- 60
If-
(])
~
-
0
'r-
~
U
(])
r- 40
r-
o
U
\.oJ
20
I
,"
,
[
i
I
:
",... ~
~ ,.
I
o
8
6
2
4
10
12
14
Particle size~ microns
Size-efficiency curve for wet-impingement
Figure 2
scrubber
>i
o
~
II
.,
-------
I1~~I!.~ng"!~P!_lt :l):p" S~~r:~~~_~~Jg Towe.r
-..- -
ran
Transition
Place
_Main Body
keClrculation
- Pump
Ejector
Pan
Figurl' :3
National Dust Collector Corp.
;J 1'h(' high gas vdocity through the
intprstiL-es of th(' packed spheres also
rt'sults in pulling watpr upward with
sufficient forc(' to disintPgrate the
watt-I' strC'arns into a tllrbulent mist in
lh,' ZOIH' rllJovC' lIJI' filtl'r bed. I!ere,
ultrrl- finc pa rti<:les aT'(' trapp('d by the
mist rind ('onstantly flut;hed downward.
,I
!\1ist ('arril'lJ by tl1l' upwaru flowing
<.:leaned gas is I'Plnoveu by passage
thl'llugh;1 lwei p:\('kl'd with porcdain
s;HldlPs,
1\ 1':1/'tj('1<- l'oll('('ntl'ation
Suc h units 1t:1 VI' 1-;1' !f-l'!eaning action
and tltpr(' is fl'l'('dom from build-up of
solids and ('as(' of cleaning.
~ COf1l'('ntratiuns of about 40 grainsl ft3
aI'(' !Tadil,y handled.
,~
C Pressure Loss
1 Pressure 106s is 4-6 in. w. g.
D Efficiency
1 Efficiency is high on two micron-sized
particles and above.
E Water Consumption
1 Fresh water: y.gpm per 1000 dm gas
cleaned
2 Recirculated water: 3 gpm per 1000
dm gas cleaned (Scrubbing liquid can
have high solids content).
1" Capacity
1 Units handle 500 to 40,000 dm.
REFERENCES
First, M. et a1. Performance Character-
istics of Wet Collectors. NYO-1587
Waste Disposal, Harvard University.
1953.
2 Stairmand, C. J. Mist Collection by Im-
pingement and Diffusion. Paper read
at the Inaugural Meeting of Midland
Branch of A. Inst. P. Birmingham,
England. October 14, 1950.
3 Stairm~nd, C. J. The Design and Per-
formance of Modern Gas-Cleaning
Equipment. Paper read before the A.
Inst. P. London. November, 1955.
4 Kane, J. M. Operation, Application, and
Effectiveness of Dust Collection Equip-
ment. Heating and Ventilating. August,
1952.
5 Nicklen, G. T. Some Recent Development
and Applications of Scrubbers in In-
dustrial Gas Cleaning. Proceedings
APCA, 52nd Annual Meeting, Los
Angeles. June, 1959.
6 Magill, P. L. Air Pollution Handbook,
M~Graw-Hil1 Book Co., Inc. 1956.
-.J
-------
~
biJ~
COLLECTORS WITH SELF-INDUCED SPRAYS
I
MECHANISM OF PARTICLE COLLECTION
1
Magnesium and explosive dusts
A
In this equipment, the particle collection
zone is a spray curtain which is induced
by the gas flow itself through a specially
designed orifice. (The spray curtain is
followed by a spray eliminator).
2
Sticky or linty materials like metallic
buffing exhausts
III
PERFORMANCE DATA
Efficiency - See figure 2 (page 3)
B
The Collection of Particles
I
Normal gas velocity of about 50 fps
creates droplets about 320~.
Water usage - 10-40 gal/1000 cfm gas cleaned
(Much or all of this water may
be recirculated).
2
Collection of particles is mostly by
impingement on the droplets during
the free-falling period of the droplets
and 31so during the period of the accel-
eration of the droplets from rest (when
high relative velocities are available).
Sensitivity - not particularly sensitive
to cfm change (at least within
+ 25% of the design rate).
Concentration - high concentrations (40 grains/
ft3) (There are no fine clear-
ances to cause chokage)
II
APPLICATION
Maintenance -
The whole apparatus is well
irrigated and periodic hosing-
down of the interior is easily
done. There is an absence of
moving parts. There may be cor-
rosion difficulties.
A
Since there is an absence of ledges,
moving parts, and restricted passages,
these units are especially adapted to
materials like:
-------
-- -------- ---
PA.C.pm.70.9.60
I
-------
Collectors With Self-Induced Sprays
------ ----
_.~--- - .--------- . --._. -----.-.-
- .------...-- ..---......-----..-------.---- - -----
P
'i
I.
f. ~
f,r
1 '
;\
J:
. ~
, ~ :~._,~.. '.Soj I ~. ~':.:'
"
-,
,
"
'.
,
, .
p ~?t:~' 0'
vj(, ,'~ .
~. ;:. :f
,',
"
':;1
- ----
Figure 1
2
-------
~
~
r;
r:
:.
-
-'
-.
:r. -.
... r:
r")
'" ~
'"
'<
"""
'n
.,
r:
'"
:;)
'"'
""
I I
I !
I I
, I I ' I
I
i i I I I
00 ! I I
I I I
~
~ ,.
/ I
,
s:r1 J
I '
i I
M1
AfI
2"
0 4 8 2 ) 20 ~4 ..dl 3 36 40
n
o
......
......
It>
n
rT
o
.,
CI)
:E::
,...
rT
::r
UJ
It>
......
....,
I
H
::s
P-
c:
n
It>
P-
Particle Size, Microns
Size-Efficiency Curve for Self-Induced Spray Collector
Figure 3
UJ
'"
.,
II>
'<
CI)
-------
Collectors with Self-Induced Sprays
REFERENCES
1
First, H., et. a1., "Performance Character-
isLlL's of Wet Collectors," NYO - 1587
Waste Disposal, Harvard University. 1953
.:'
Stuirrnand, C.J., "Mist Collection by Im-
pingement and Diffusion", paper read
at the Inaugural Meeting of Midland
Branch of A. Inst. P., Birmingham,
England. Oct. 14, 1950.
3
Stairrnand, C.J. "The Design and Performance
of Modern Gas-Cleaning Equipment," paper
read before the A. Inst. P., London.
November, 1955.
I,
4
Kane, J.M. "Operation, Application, and
Effectiveness of Dust Collection Equip-
ment," Heating and Ventilating. Aug.
1952.
5
Nicklen, G.T. "Some Recent Developments
and Applications of Scrubbers in In-
dustrial Gas Cleaning," Proceedings,
APCA, 52nd Annual Meeting, Los Angeles.
June, 1959.
6
Magill, P.L. Air Pollution Handbook, Mc-
Graw-Hill Book Co., Inc. 1956.
-------
DISINTEGRATOR SCRUBBERS
I
MECHANISM OF PARTICLE COLLECTION
II
OPERATION
A
Since for high collection efficiency there
must be a small obstacle (D ) and a high
relative velocity between tRe obstacle and
particle (v I ), attempt is made to ap-
proach thisP18eal by:
A
A disintegrator scrubber consists of an
outer casing containing alternate rows of
stator and rotor bars, the relative velocity
between adjacent bars being of the order.
of 200 - 300 fps.
1
Shooting water drops at the particles
so that a high relative velocity (v I )
p 0
will be obtained (even if such velocities
are maintained for short periods) and
arranging that this be done so that a
very large number of impacts will be
achieved.
B
Water is injected axially and is effectively
atomized into fine droplets (say 25~) by
the rapidly rotating vanes.
C
The dust-laden gas also enter axially and
passes through the dense spray zone where
the particles are subjected to intense
bombardment by the water droplets.
B
Such action is incorporated in the disinte-
grator scrubber (Figure 1).
Water inlets
Stators
Rotors
Oi rty gas inlet
Clean gas
Exit
Effluent
Fi gure 1
PA.C.pm.69.9.60
1
-------
Disintegrator Scrubbers
111.
PEIU'ORMANCE DATA
Efficiency. . . . . . . . . . . . . . . . . . . highly efficient. See figure 2
for a size-efficiency curve.
Pressure drop. . . . . . . . . . . . . . . . . .less than l-in. w.g.
Energy usage. . . . . . . . . . . . . . . . . .
high power requirements. Total
power consumption may be 16-20
HP per 1000 cfm gas cleaned. This
power is largely expended in atomizing
and accelerating the water.
Water consumption. . . . . . . . . . . . . . .
.usually preceded by conventional
collectors as cyclones and scrubbers
to insure that low concentrations of
the order of ~ to ~ grains per cu ft.
are presented to the unit. These pre-
cautions are necessary to avoid build-
up in the disintegrator, which, run-
ning at high speed with fine clearance,
is particularly susceptible to trouble
if operated under unsuitable conditions.
2
-------
Disintegrator Scrubbers
20
/
J
I
I
100
80
60
40
2
3
..
5
6
7
8
9
10
11
12
13
14
15
Particle Size, Microns
Size-Efficiency Curve for Disintegrator Scrubber
Figure 2
REFERENCES
4
Kane, J. M. Operation, Application, and
Effectiveness of Dust Collection Equip-
ment. Heating and Ventilating. August,
1952.
1
First, M., et al. Performance Character-
istics of Wet Collectors. NYO-1587
Waste Disposal, Harvard University. 1953.
5
Nicklen, G.T. Some Recent Developments
and Applications of Scrubbers in In-
dustrial Gas Cleaning. Proceedings
APCA, 52nd Annual Meeting. Los Angeles.
June, 1959.
2
Stairmand, C.J. Mist Collection by Im-
pingement and Diffusion. Paper read
at the Inaugural Meeting of Midland
Branch of A. lnst. P. Birmingham,
England. October 14, 1950.
3
Stairmand, C.J. The Design and Performance
of Modern Gas-Cleaning Equipment. Paper
read before the A. lnst. P. London.
November, 1955.
6 Magill, P.L. Air Pollution Handbook
McGraw-Hill Book Co., Inc. 1956.
3
-------
WET CENTRIFUGAL COLLECTORS
TYPES OF WET CENTHIFUGAL
CQI,I,ECTORS
A Irrigatl'd Typt's
Till'S(, rely upon the throwing of parti-
,'ks a~aillst wpttcd l'ollf'ctcd surfaces,
:-ill"h [IS wetted walls or impingement
pia tes by centrifugal action.
B Spray Chnmber Types
1 These depend upon impaction of the
particles upon spray droplets and the
subsequent precipitation of the "dirty"
spray droplets upon the wall of the
unit by centrifugal action.
II
IRRIGATED TYPES (Figure 1)
WET CENTRIFUGAL COLLECTORS
c;--
4.
A Clean ai r outlet G
B Entrainment separator H
C Water inlet
D Impingement plates
E Dirty air inlet
F Disintegrator
Inspection -door
Wet cyclone for
collecting heavy
materi a 1
Water and sludge
drain
Figur~ 1
American Air Filter Co.
PA. C. pm. 72. 9. 60
A The efficiency of a centrifugal collector
may be increased by irrigating its walls,
if the attendant disadvantages of a wet
system can be tolerated.
B Water distribution may be from low
pressure nozzles or gravity flow.
C Performance Data
. .3-5 gal/lOOO cfm of
gas treated
Draft loss. . . . . . . 2i to 6"
Water rates.
Draft loss sensitivity
to cfm change. . . . . as (cfm)2
High efficiency on
particles of mass
median greater than. . l-51!
Efficiency sensitivity
to cfm change. . . . . yes
Humid air influence
on efficiency. . . . . none
Gas temperature. .
"unlimited"
III
CYCLONE SPRA Y CHAMBERS (Figure 2)-
A Ope ra tion
1 The dust-laden gas enters tangentially
at the bottom and spirals up through
a spray of high velocity fine water
droplets.
2 The dust particles are collected upon
the fine spray droplets which are then
hurled against the chamber wall by
centrifugal action.
3 An unsprayed section above the nozzles
is provided so that the liquid droplets
containing the collected particles will
ha ve time to reach the walls of the
chamber before the gas stream exits.
1
-------
Wet Centrifugal Collectors
PLEASE-ANTHONY CYCLONIC SPRAY SCRUBBER
cleaned gas
core buster disc
swinging
damper
spray manifold
tangential
gas inlet
inlet
inlet
outlet'
Figu re 2
Chemical Construction Corp.
H Effie icncy
Effidl'ncy of dust removal is given by:
E
1 - e
~i1? ['WH
2DoQ
where:
E
efficiency of collection
11 = individual droplet efficiency
r
- radius of the cyclone (the
length of the path of the droplet)
volume rate of liquid through
the nozzle
W
D,~
diameter of the droplets
volume rate of carrier gas
Q
H
height of tower (The drops
should not be made too I:Imall
1:;Jt1("C entrainment may occur,
requiring an incrpase in the
hdght of the' tower)
2
2 Operating Conditions
Gas flow. . . . . . . . 500-more than 25,000
cfm
Gas velocity into
cyclone. . . . . . . . up to 200 fps
Separation factor. . . 50 to 300
Efficiency. . . . . . . 97+0/0 on dust above 1....
High efficiency on
particles of mass
median greater than
Efficiency sensitive
to cfm change
Draft loss. . . . .
. O. 5 - 5....
. yes
2-6,tw.g.
Draft loss sensitivity
to cfm change. . . . as (cfm)2
Water usage .... .3-10 gal{1000 cuftof
gas cleaned
Humid air influence
on efficiency. . . . . none
Gas temperature. .
.pre-cooling of high
temperature gases
necessary to prevent
rapid evaporation of
fine droplets.
.1 to 3 HP/1000 cfm of
gas
Power requirements
REFERENCES
First, M., etal. Performance Char-
acteristics of Wet Collectors. NYO-
1587 Waste Disposal. Harvard
University. 1953.
2 Stairmand, C. J. Mist Collection by
Impingement and Diffusion. Paper
read at the Inaugural Meeting of
M"idland Branch of A. Inst. P. Birming-
ham, England. October 14, 1950.
3 Stairmand, C. J. The Design and Per-
formance of Modern Gas-Cleaning
Equipment. Paper read before the A.
Inst. P. London. November, 1955.
-------
4
Kane. .J. M. Operation. Application, and
Effectiveness of Dust Collection Equip-
ment. Heating and Ventilating.
August, 1952.
5
Nicklen, G. T. Some Recent Developments
and Applications of Scrubbers in
Wet Centrifugal Collectors
Industrial Gas Cleaning. Proceedings
APCA. 52nd Annual Meeting. Los
Angeles. June, 1959.
6 M3.gill, p. L. Air Pollution Handbook.
M~Graw-Hill Book Co.. Inc. 1956.
3
-------
VENTURI SCRUBBERS
I
MECHANISM OF PARTICLE REMOVAL
A Since for high collection efficiency of fine
particles by impingement there must be a
small obstacle (Do) and high velocity of
approach of the gas stream relative to the
obstacle (vp( 0)' attempt is made to ap-
proach this ldeal by:
1 An arrangement in which very small
water droplets (upon which the particles
impinge) are formed by the gas flow so
that the droplets are initially at rest
at the time of impact with the particles.
Even during the period of acceleration
of the droplet, high relative velocities
will be maintained since the particles
move at the velocity of the gas stream.
a Such an arrangement is incorporated
in the Venturi scrubber. See
Figure 1.
II
OPERATION (Figure 1)
A Collection of Particles upon the Droplets
1 In the Venturi scrubber, the particulate-
laden gas passes through a duct which
incorporates a Venturi scrubber.
2 At the throat, high gas velocities of the
order of 200-600 fps are attained.
3 Coarse water spray is injected into the
throat by way of radial jets in quantities
of 5 to 7 gpm per M dm of gas.
4 The high gas velocities at the throat
immediately atomize the coarse water
spray to fine droplets (about 50 microns).
5 Since, at their genesis, these fine drop-
lets are initially at rest relative to the
particles in the gas stream, it is at this
moment that collection efficiency is at
its maximum. (vp/o) is maximum.
PA. C. pm. 68a. 5. 61
a The atomized droplets, being fine,
rapidly accelerate to the velocity
of the carrier gas; but even during
this short period, relative velocities
will be high and effective collision
between droplet and particle will
take place.
It is during the period before the
droplets attain the same velocity
as the gas stream that any relative
velocity between the droplets and
particle is obtained. For example,
a 100-micron droplet introduced
into a gas stream moving at 100
fps would accelerate to 900/0 of the
gas velocity in 16 inches; a 20-
micron droplet would reach 900/0
of the gas velocity in 2 inches.
B Removal of the Dirty Droplets
1 As the gas decelerates after passing
through the throat, agglomeration of
the particle-laden droplets takes
place.
2 The large agglomerates are readily
removed by a cyclonic separator.
III
EFFICIENCY
A Effect of Pressure Drop on Efficiency
The higher the pressure drop, the
higher the removal efficiency of
particles. See Figures 2 and 3.
2
Pressure drops across the Venturi
of 25-30 inches of water gage may be
expected.
3 Pressure drop can be increased (and
hence efficiency can be increased)
sim!>ly by increasing the gas velocity
and/or the water injection rate. See
Figure 4.
-------
Venturi S
crubbers
.. ~rr;'l).,
.---.u ~,
..)
Cyclon
e scrubber
Orl flc
e scrubber
Ventu .
rl scrubber
2
2
Figure 1
--
-------
-----~ ---
Venturi Scrubbers
~
>. 100
u
.:
~
....
u
....
'"'
~ 95
.-I
'"
:>
o
e
~
A
B
10
20
30
..0
Venturi Prf'ssure Drop (in. w. g. )
Curve A: Rotary iron powder kiln
B: Lime kiln, asphalt plant
..-.
'"'
u
en
........
en
d
....
'"
""
00
.......
.u
~
.-I
.u
::!
o
C: Iron cupola
D: Phosphoric acid plant (acid mist)
E: Incinerator (sodium oxide fumes)
Figure 2(5)
10
20
50
30
..0
Venturi Pressure Drop (in.w. g.)
Curve A: Cupola gases
B: Blast furnace gases
Figure 3(5)
00 25
. ;;.
d 20
....
"
~ "
V
-j JI'
1.1' /'
..... """""
-
'-
c z 8 0
~ 15
o
'"
l' 10
~
~ 5
en
Q)
~
'"
!:Io
6
Water/Gas Ratio, Gal/1000 cu. ft.
Relation Between Prp.ssure"}osE
'SDd Water Usage in Venturi
Scrubber
Figure 4
4 When gas cleaning requirements change,
the only adjustment necessary to the
Venturi scrubber, in most cases, is
in the flow of scrubbing liquid to in-
crease the pressure drop. Thus higher
cleaning efficiency is accomplished
without modification or addition.
B Effect of Particle Concentration on
Efficiency
1 If the number of water droplets is held
constant and the number of particles
(concentration) is increased, the number
of collisions would be expected to in-
crease. In other words, collection
efficiency should increase as loading
increases.
2 This increase, however, is due not
only to the increased chances of particle
collision wi th droplets, but also due to
collisions between the particles
themselves.
C Size-Efficiency
1 The Venturi scrubber approaches
1000/0 for all particles larger than 1. 5
to 2 microns.
2 Figure 5 shows a size-efficiency curve
for a Venturi scrubber( 1). Sizes above
2-microns were obtained on special
3
-------
100
-80
.j.J
t::
Q)
0
1-4
Q) -601
p.,
:»
o
t::
Q)
~
0
~
4-1
4-1
~
t:: -4Q-
o
~
.j.J
0
Q)
r-I
r-I
0
u
20
< '
--- -- ------~ - -- --
o
1
12
8
3
4'
5
6
7
Particle Size, Microns
Size-efficiency Curve for Venturi Scrubber (6-in. throat)
Figure 5
(3.500 cfm gas)
~
-------
. - -- -----.---
Venturi Scrubbers
TABLE 1
TYPICAL PERFORMANCE DATA FOR VENTURI SCRUBBER(5)
Approximate Loading Average
)1ze Range (Grains/ cf) Removal
Source of Gas Contaminants (Microns) Inlet Exit Efficiency (%)
IRON & STm INDUSTRY
Gray Iwn Cupola Iroll. Coke. SillCJ Ou,' .1.10 1.~ .05-.15 %
O'YK~II Steel COIIVClltl Iron O.ido 5.2 8-10 .05-.08 98.5
\teel Upon Hed/lh 1 .lnil"" ,$11.11'1 Iroll X. line Ihide .08.J .5-1.5 .03..06 35
$Icd O~CII Hearth fJlliaCI lion O.i~c 5-l 1-6 .01..07 99
(Oxygen lanced)
Bla~1 furnace (Iron) Iron Ore & Coke OUSI .5.20 3-24 .008-.05 99
Electric furnace ferro.Mansanese fume .1.1 10.12 .1)4..08 99
Electric furnace ferro.Sillcon Dust .1-1 1-5 .1-.3 92
Rotary Kiln-Iron Reduction Iron, Carbon .5-50 3.10 .1..3 99
Crush ins & Screening Taconite tron Ore Dust .5.100 5-25 .005-.01 99.9
CHEMICAL INDUSTRY
Acid-Humidlfled SO. H,sO. Milt
(a) Scrub with Water 303" 1.7. 99.4
(bJ Scrub with 40% Acid 406. 2.8. 99.3
Acid Concantrator H.SO. Mist 136. 3.3. 97.5
Copperas ROlStlng Kiln H'sO. Mist 198. 2.0. 99.
Chlorosulfonic Acid Pllnt H,sO. Milt 756. 7.9. 98.9
Ory Ica Plant Amini foe 25. 2.0. 90+
Wood Distillation Plant Tar & ACltlc Acid 1080. 58.0. 95
TiCI. Plant, TlO. Dryar TIO"HCI Fum81 .5.1 1.5 .05-.1 95
Spray Dryars Datareents, Fuml & Odor 95
FllSh Dryer Furfural Dust .1.1 1.1.5 .05-.oe 95+
Phosphoric Acid Plant H.PO, Mist 192. 3.8. 98+
NON.fERROUS MnAl$ INDUSTRY
Blast furnaci (Sac. Leadl Lead Compounds .1-1 2-6 .D5..15 99
Raverberatory Leed Fumlce Lead & TI~ Compounds .1-.8 1.2 .12 91
Ajax furnace-Alumlnum Alloy Aluminum Chloride .1..9 3.5 .02..05 95
Ilnc Sinterine Ilnc & Lead Oxide Dusts .1.1 1.5 .05-.1 98
Reverberatory Brass Furnace linc Oxide Fume .05-.5 J.8 .1..5 95
MINERAl PRODUCTS INDUSTRY
Lime Kiln Lime Dust 1.50 5-10 .05-.15 9t+
Liml Kiln Soda Fuml .3-1 .2-5 .01..05 99
Asphalt 5tona Dryer Llmestona & Rock Dust I-50 5-15 .115-.15 98+
Cament Kiln Cemant Dust .5.55 1.2 .115-.1 97+
PETRDUUM INDUSTRY
Catalytic Rlformer Catalyst Oust .5-50 .os .005 95+
Acid Concantrator H,sO. Mist 136. 3.3. 97.5
TCC Catalyst Reeanerator 011 Fumes 756. 8.0. 98+
rtRTlIIZER I!lDUSTRY
Fartilizar DrYlr Ammonium Chlorlda Fum81 .05-1 .1-.5 .os 85+
Superph01phate Oan & Mlxar Fluorlna Compounds 309. 5.5. 98+
PULP . PAPER INDUSTIY
lIml ~iln Llml Dust .1-50 5-10 .05-.15 99+
lime Kiln Sodl Fuml .1.2 2.5 .01..0& 99
811ck Liquor Recovlry Bollar Silt Cakl 4-6 ."'.8 90
MISCEllANEOUS
Plckllne Tanka He! Fum.. 25" U" 90+
Bollar Flua '0.. Fly Alh .J.3 1.2 .05-.01 98
Sodium Diaposlllncinerator Sodium Oxlda Fumes .3..1 .5-1 .02 18
Not,': T", ,lIIot."ot.. '''0- 011017. are overag. value. lur a partioutGr " MlIlI,rllll8 per cublo ft
ptGld 01' group 01 ,,,.taltGt/oK' op.ratiKg UWI' a .p.otjlo .et of oondit~.
5
-------
Venturi Scrubbers
silica dust powders and those for the
smaller sizes on dispersed non-patho-
genic bacteria. This size-efficiency
curve suggests a very high efficiency
for a comparatively simple piece of
equipment.
D OVt'rall Efficiency
Table I shows some efficiencies of collec-
tion experienced by various installations.
THE ~B 8-Jr VJl:N'TV.1
The Chemico Type S.F Venturi Scrubber Is particularly
recommended lor these hard.to.handl. situations: re.
mov.' 01 "sticky" solids from gases; recycllnl of
heavy slurries where weter supplies are IImltedj and
racovery of process materials In con centra tad form.
In the S.F Venturi, scrubbing liquid Is Introduced
through troughs at the top of the unit. The liquid
flows downwardly In a continuous film alonl tha slop-
Ing wells to the deflecting lips, which direct It across
the throat of the Venturi to be atomized by the force
of the high velocity gas.
fi
IV
ENERGY USAGE
A Since pressure drops of 30 inches water
gage correspond to 120 kwh per million
cubic feet of gas cleaned, efforts have
been made to reduce the pressure drop.
However, if pressure drop is reduced.
there is a tendency to reduce the efficiency
also.
E Additional high energy usage results from
the method of injecting water into the
Venturi throat. See Figure 6.
THE TYPE ..A V8NTVBZ
The Chemlco Type P.A Venturi Scrubber Is most ef.
fectlve In the vary dlmcult application. raqulrlna
efflclant removal of sub-micro. dust, fume, Ind milt
particles.
Chemical Construction Corp.
Figure 6
-------
.- -- - _. -- -- - ---- --------------
v
PI';IU'OHMANCI'; DAT/\
Venturi Scrubbers
Gas flow--------'----- -------- ---------..--------- 200 to over 145,000 dm
Gas velocity through throat--.--------------------- 200-600 fps
Pressure loss--------------------..-------..-...----up to 25-30 in. water gage
Gas temperature- - -- - -- - - -- - -- - - - -- . - - - - -.u... - -.- - -- "unlimited"
Overall effkiency-----------------------_. ---------usually high (97 - 99""0/0)
High efficiency on dusts with mass median
Size greater than--------------------._---_..------- 0.5-2....
Humid air influence on efficiency- -- - - -- - - - - - - - - - --- none
Water usage------------------.-----------------. --5-7 gpm of water per
M dm gas
RE FERENCES
Stairmand, C. J. The Design and Per-
formance of Modern Gas-Cleaning
Equipment. Paper n'ad before
A.lnst. P. London. Novem\wr, 195!i.
2 Nicklen, G. T. Some Recent Df'vclopments
and Applications of Scrubbers in In-
dustrial Gas Cleaning. Proceedings
APCA, 52nd Annual M£'eting APCA.
Los Angeles. June, 1959.
3 Jones, W. p. Development of the Venturi
Scrubber. Ind. Eng. Chern. Nov. 1949.
4 Basse, B. Gases Cleaned by the Use of
Scrubbers. Blast Furnace and Steel
Plant. Nov. 1956.
5 Chemico Gas Scrubbers for Industry.
Bulletin M-104, Chemical Construction
Corporation, 525 West 43rd Street,
N. Y. 36, N. Y.
6 Venturi Scrubbers for Industry, Bulletin
M-I03A, Chemical Construction Cor-
poration, 525West43rdSt. N. Y. 36, N. Y.
7
-------
Section Six
OVERVIEW OF GASEOUS CONTROL
Control of Vapors and Gases
-------
CONTROL OF VA PORS AND GASES
INTRODUCTION
c
Flares
A The method used to control a gaseous
pollutant depends upon its properties.
1) Steam injection
2) Venturi
B Methods of Control Include:
3 Destruction of products of combustion
Combustion
a
Flame combustion
a Gases and vapors liberated from a
direct fired heater as products of
combustion will not be incinerated
when recirculated through the heater
at the normal temperature main-
tained in the heater. Complete
combustion can be attained, however,
in i1 separate combustion chamber
call~d an afterburner provided the
temperature is maintained at 900
to 1400oF.
b Catalytic combustion
2 Absorption
3 Adsorption
4 Closed collection and recovery systems
(hydroca rhon vapors)
~
Masking and counteraction (odors)
b The afterburners have provisions
for maintaining continuous and
intimate mi:nng of the contaminant-
laden gas and the flame trom an
auxiliary burner. The chamber is
proportioned such that the gas
velocity and gas flow patterns
established will produce adequate
retention time in the combustion
zone. At temperatures of 12000F
and higher, the average retention
time in such units is O. 2 to O. 3
seconds.
II
COMBUSTION
A A combustion process can be utilized to
greatest advantage when the gases or
vapors to be controlled are organic in
nature.
B Flame Combustion
There are four f~ctors which govern
the effici~ncy and economy of flame
c9.mbustion as a means of controlling
gaseous pollutants.
c Combustion fumes can be burned in
the same manner as products of
combustion in a similar comhustion
chamber.
a TempI'f'atur!'
h Time
d
Flares are used primarily to dispose
of hydrocarbon gases which may be
released intermittenly in certain
processes.
c Oxygt'n
d Tu dmlence
2 Eql1ipmf'nt employing the principle of
flame combustion include:
C Selected Applications of Flame Combustion
a
Fume and vapor incinerators
Paint and varnish industries use fume
incinerators to dispose of fumes emit-
ted from kettles used in the cooking
process. (See Figure 2. )
b Afterburners
PA. C. ge. 13.5.60
1
-------
Control of Vapors and Gascs
"AU ,. "...."'...
.n.L "'''.
I.,ULA"" ".""U
'.".e".. 'n. ""LI
""L. 'U_'''~
". 11/'...
...IIIIU ... aliI
"II IIlnUIi
~
~
,
unlOll .
lie ".. A
DIAGRAM OF A
WASTE GAS AND ODOR INCINERATOR (Reference 2)
Figure 1
Discharge to
stack
/:j-.
',' ~,
., .
,. ~
" .
~::':: I
,~ .
~ "
. ".\
:~~:~'~'::.;\"':-".: .
Blower 1
Fume
Incinerator
... , ' ,\
: ,.: ":',', It.. =".: ..I:I'~I' ~.'.14
,'I'.
, ,.
Jj':":
, .
"" ,I . ",' .' . ,,; .'.
'... , . . '.
. ~..:\': ~ ''''',. . .. ,. :.
". ".'.
" .
Air intake
"- Open Kettles ~
Closed Kettle
LA YOUT OF FUME COMBUSTION SYSTEM
FOR PAINT AND VARNISH COOKING
z
Figure 2 (Reference 6)
-------
2
Coffpl' induHtricfj apply t.his method to
destroy odorl::l in their C'xhallst gases.
a
The pn'mix typt' and Venturi tYPt'
burners are most frequently used
in these units.
J
The use of afterburners on incinerators
has met with varying degrees of success
depending on the kind of afterburner
used and the type of incinerator.
a
Residential incinerators with an
afterburner chamber included in the
design of the unit are available.
b
The performance of flue fed apart-
ment hOllse incinerators can be im-
proved with the installation of either
a basement afterburner or a roof
afterhurner,
1) BasC'ment afterburn<,r - 50%
deC'rt'ase in particulate emissions.
2) Roof afterburner 95% decrease
in particulate C'missions
c
The use of one or more afterburners
on auto body incinerators is neces-
sary to control the emissions normal-
ly encountered.
T~ Air port
~
Burners
Ch.Hging rloOl'
C:OTnhllstion (',!lan!!>"'I'
FLUF: t'I':n J\.PAHTMr'~NT
HOUSE INCINEf! ATORS
F'igurl' 3 (Reference 5 )
Control of Vapors and Gases
4
Flares arc ust'd quite extensively in
refinery operations to dispose of lal'ge
emergency releases of hydroca r'bon
gases caused by abnormal conditions
(such as compressor failure. )
a
Flare design must provide for
smokeless combustion of gases of
variable composition and a wide
range of flowrates.
b Venturi flares mix air with the gas
in the proper ratio prior to ignition
to achieve smokeless burning.
c
Steam injection flares mix steam
with the stack gases as they reach
the top of the stack. The injection
of steam suppresses carbon forma-
tion by:
1) Separating hydrocarbon molecules,
thus reducing polymerization.
2) Inducing the formation of oxygen-
ated compounds which burn at a
slower rate at temperatures not
conducive to cracking and
polymerization.
D Catalytic Combustion
1
Application
a
When concentration of combustible
portion of gas stream is below flam-
mable range.
b In place of flame combustion when
treating large volumes of cool gas
that would make fuel costs
prohibitive.
c
When lower operating temperatures
are desired.
2
Important cha l'aC'teriRtin;
a Low resistance to the flow of gaseR
b
High specific surface
c
Arrangement in a manner to provide
turbulent mixing of process gaseR
3
-------
Control of Vapors and Gases
---------
t
"
,','.',',
,',',',',
I
::::!{~
Settling Chamber
':-;,i::,:(::;':,
... '.:':""?"<'':i£:;r;z,~i;;i:~..
Hoot'
. ""',.
"," "",",.
ROOF'
AFTEHBURNlm
Figure
6
Stack
Automatic
temperature
control
Afte r
Chamb(' r
..
'!:
'::
,\';
.'
'.
.'
.~.~
,",'
'~
, ",..
'~.' , ;<':"'..h~:.:,1 eO;
PIT-TY PE INCINERATOR WITH AFTERBURNER
FigurE' 5
(From Air Pollution Association Paper 58-30)
.j.
-------
Control of Vapors 'lnd Gases
Cap with
drilled orifice
dt
1
DIAGRAM OF VENTURI BURNER
Figure 6
:1
Des lrut' Hon or PI'O, 'f'S S gas('s
a
1'11(' prOt't'SS gases art' passed over
spedal PlI'I1H'ntR coated with a
catalytic m.1tPl'ial, and oxidizable
l'nn,<.;titu('nts in thc gasps rpact with
<'XCPSS oxygt'n to form carbon dioxide
;lnd watl'r vapol' and to Jibf'rate hent.
Catalysts of inlerf'st in oxidation
rc3t,tinns are "I'I'tClin m,~tals oxides
slIl'h as platinum and platinum-
rhodium alloy.
b
Catalytic combustion of most organic
l'onstitupnts that oc('ur in process
dflu('nt gases is initiated and sclf-
sustaining at about 5000F. If thp
gases arc colder than this before
coming into eontact with the catalyst,
they ITlI1Rt 1)(' prcheated.
t'
If tlw ,'om '('n tra tion of oxid izabll'
t'onslitupnts in the pr'ocess gascs is
SUf'l'l., icntly high, ('nough hl,at will be
1 iIH'I'al('d by tlw oxidation 1'l'[l('tions
at till' catnl)':;t sudat'c to mllstion has lH'eTi initiatpd.
d
TI\<' tel1l!)('I'atUI'l' ris(' may Iw high
('nough to I11:1kl' it (,.'onomka] to
"Jllploy :1 111':11 ('x<'lwng('J' t.o r('('ov('r
t.he l1t'at. 1'01' otlH'r purposes, such as
p,'chcating the cfflul'nt gases or
1'."Ilt'I'ating st('am.
"
Substantial sClvings are possible by
t.l1t' usc or Iwat cxehangl'rs and by
r'l't'\ ding SOITl,' of thf' gases lpaving
till' .'atal)'st systl"lTl.
4
Limitations
a
Optimum temperature range is be -
tween 500 and 18000F.
b
Treatment of gases containing ex-
cessive amounts of particulate ma l-
tCI', such as ash or fumes from 7.il1( ,
lead, and mercury, reduces the
effectiveness of the unit due to a
coating that forms on the catalyst.
E Selected Applications
Control of efflupnt gases, fumes, and
odors from:
a
Paint and enamel baking ovens
b
Coffl'C' roasting procC'sses
c
Foundry' 'ore' baking ovpns
d
CIH'mica] plants discharging maleic
and phthalic anhydrides
c
Kettles used for cooking animal,
vegetable, and mineral oils
f
Phenolic-resin curing ovens
g
Refineries burning wasil' cracking
gases
1II
ABSORPTION
A PrincipII'
The rffluent gases are passed through
u bsa rbl' 1'8 (sC'rubbe rs) whi('h conta in
liquid absorbents that r('mov(', trl'clt.
or modify on(' or 11101'1' of the offl'nding
('onstitul'nts in the gas stream.
2
The pffidpl1l'Y of removal dC'pends upon
Scv(','al fal'tors.
a
The amount of surfac(' l'ontad bc-
tWt'f'n gas and liquid. The greatC'r
thC' surfacl', the greater will be thc
absorption.
5
-------
Control of Vapors and Gases
~:XII/\II~"
..
( :\ 1 \ 1 'S 1
..
III t '\\ I'j{
..
,
\',\ 1'..\1.' 'I]l \"Uf\IIItISTll)N IINI'! ~'Plt WI\S'II< 1-"\1).:1. ('ON'I nol. ON 1\ COOKING KETTI.[': I.INF:
l.'igur.' "
b
Contact time.
d
Fluorides
c
The concentration of absorbing
medium.
e
Nitrogen oxides
C Absorbers
d
The speed of reaction between the
absorbent and the gases.
Packed tower
B Liquid Absorbents
a
Consists of a vertical shell, filled
with a suitable packing material.
Liquid absorbents may be either non-
reactive' or reactive. Non-reactive
liquids dissolve the gas with no chemi-
cal reaction involved. A reactive
liquid removes the pollutant through a
che'mical reaction, transforming it into
a If'sS offensive form.
b
The liquid flows over the surface
of the packing in thin films, thereby
presenting a large liquid surface in
contact with the gas.
2
Plate tower
')
The'I'(' are' two kinds of rpaC'tivc liquid:,;,
tf1l' rt'g('!wrativ(' type and the 110n-
regenerative type. The' formE'r may be
treatf'd and reused whereas the latter
must be disc::\rded aftf'r one application.
a
Consists of a vertical shell in which
are mounted a large number of
equally spaced circular perforated
(Sieve) plates.
b
Gases and vapors bubble upward
through the liquid seal above each
plate. This passage of gases through
the perforations prevents liquid
from passing through the holes.
;J
AbslJrbents may be used to remove:
a
Sulfur dioxide'
b
Hydrogen sulfidf'
Sulfur trioxide'
l'
6
-------
Control of Vapors and Gases
:3 Bubble-cap plate tower
b Gas ?ses through the chimney, is
diverted downward by the cap, and
discharged as small bubbles from
the slots at the bottom of the cap
beneath the liquid.
a Consists of a vertical shell in which
are mounted a large number of
equally spaced circular bubble-cap
plates.
r--- PA~K;; -;WE~ - A;SOR8!"-
I UGllIII INI n. ata
I
IlU8BL!: PLAT! TOW!:R
I'ACl
-------
Control of Vapors and Gases
lUll. A- ~ ""'.MII8IB...
F'igure 11
SPRAY TOWERS
.!9.9 I'lL TEIt
~
i
.AI IIILIf
AI..
_~IL
..TIII ......
Figure 12
(Courtesy of Manufacturing Chemists I Assoc., Inc.)
_W~H:~ ~EJ__SCRU~.BE"-.
.I.!Q!JfD. f.LIO_.loO PSfG..
~UlNT
-J.LjJfi"
_.~~
8
Figure 13
(Courlesy of Manufacturing Chemists I Assoc., Inc.)
I
--
-------
Control of Vapors and Gases
6
Limitations
a
Temperatures below lOOOC are
necessary for proper operation.
1) Makes it necessary to cool stack
gases. This destroys natural
dro.ft and imposes a large cooling
load all the plant.
b
Therc is some carryover of the
absorlwnt and hence, the creation
of a new air pollution problem, un-
less entrainment separators are
installed.
c
Tbere may be a problem of corrosion.
IV
ADSORPTION
A
Principle
The effluent gases are passed through
adsorbers which contain solids of a
porous nature. These solids attract
the gases to their surface where they
are retained.
2
The amount of gas that can be adsorbed
depends on:
a
('OI1<'I'l1l.ra tion of tlH' gas
I) Prl'ssul'('
2) T('l1Ip('['atul'l'
II
l'hyskaJ and ehl'mi<'al ('hal'a('ter-
i~;ti('s of thp adsorb("nt
('
Thp slIda,'c ar('a p('r gram of
adsodH'1I1
:J
Three st('PS are J}('('cssary in the
r('moval of air pollutants by adsorption.
a
Contad of till' gasf'ous or vaporous
pollutant with the solid adsorbent.
I)
Scpa I'a lion (d('sorption) of the ad-
sorh('d gascous pollutant from the
solid ;1dsorbent (r('gpnC'ration) or
l'ppl~l<'('n1('llt of thl' adsorbl'nt.
c
Recovery of the gases for final
disposal (when regeneration is
practiced) .
B Common Materials Used in Adsorbers
Include:
Activated carbon
2
3
Silica gel
Lithium chloride
4
5
Activated alumina
Activated hauxite
C Pollutant Size Limitations
Upper size limit is generally in the
range of molecular size. They must
be small enough sO that Brownian
motion will insure effective conta< t
by collision between them and the
grandular adsorbent.
2
Lower size limit is set by the require-
ment that the pollutant must be higher
in molecular weight than the normal
components of air. Generally, molecu-
lar weights greater than 45 are readily
removed by physical adsorption.
D Desorption
Desorption may be accomplished hy
raising the temperature of the granular
bf'd above the boiling temperature of
thC' adsorbed pollutant. ThC' tPml)(>ra-
tun' may be raiser! by use of:
a
Supe rhea tf'd s tf'a m
Submerged heating clements
b
c
Circulating hot air or combustion
gases
2
Desorption may also be performed l,y
reducing the pressure.
:{
Oils or petroh'um products may be
r('movcd by burning.
4
Ch<'mical trpatmC'nt may also b('
SU('('('ssful.
9
-------
Control of Vapors and Gases
--.---
I'; Ad!-lorbers PruviJt>d with Adivated Carbon
Activatpd CarL]()ll appears
sorbent most suitable for
organic solvent vapors.
to be the ad-
recovering
2
It adsorbs substantia lly all the vapor
from thf' air regardl(~ss of variation
in l'oncentration, temperature, and
humidity conditions.
:3
Adsorption of organic solvent vapors
is virtually 100 percent efficient and
independent of concentration until satura-
tion is reached.
4
Overall recovery dficiency of 90 per-
cent can be expecLed,
5
Standard filtt>r cells U'-'igure 14).
a
Packed vessels (Figure 2) or towers
(Figure 3).
j' I
I
I
It ,:,
10 .' .
,; ,
~~<,
~".
"
."
I
. ~
"
" ~
~, :'I~
, I. '.
.. ..\
,frti(..t,,1 Cd,bo" Cd""''',
v
COLLECTION AND RECOVERY
A In the ca/;:;t' of petroleum storage tanks
where there is considerable evaporation,
it is possible to collect and condense the
vapors thus preventing losses to the
atmosphere.
B Floa ting roof tanks are also employed to
reduce the evaporation losses.
C Vapors evolved during the production,
storage, refining and marketing of
petroleum may contribute significantly
to the air pollution problem. In Los
Angeles, for example, during 1958 it
accounteJ for about 17 percent of the
hydrocarbons found in the air.
()
-------
Control of Vapors and Gases
ACTIVATED CARSDN ADSDRBER
-,
.b:=t.
,~
r
2\I!L.~~ aUCTIoN
PRODUCING UNIT
Figure 15
Figure 1G
1tt,..,tlU"...o la, MlaDr8
,£12J2~,E~ =~~=:--.~
IU[ "OIl ... a..
/ )
- - --.-: 7'/ I Of' u. ".-.
//' 1...00110
. ".'"'1-
. C08IDr."""1 ACCW1A."'CIIt
/ t tat COIIN.tSOW
/ . \.1&. 0"" COOLI.
~ ' "r Otf. "(*'[81
Q 2 ~E £ I.U' "<...1..
. ,,, oa. "'"..
'l~- -- - - " II ........ .(800.1.
r4-~ -'0,_- =~ -.- - J. ---:..:..-:-7!./ If 1'""(. cOllOtwu:a
:, : ,/ / TO M~ f" ~' I
:1 / - -,
I: tA._-
j I / OIl ,.. - . -' I
. .., ... ........... : i / .. ~ [ .~ ~~E=t-: ",:~_..m
.. ."11""''' In "'1"'-"'01' ~" i lot . ~~D
f1t" JUoL
I ~..
- - - - .. . --.- - ---- - .-
~AGRAM OF A VAPOR RECOVERY SYSTEM
Figure l7
11
-------
,,"III'l)\ ,)f Vapor_~_~_nd G~~l~.__--_-
\' [
t\1/\SI\.\N(j ANI) CO!TNTI-:nACTION
1\
I\1.lsking l'nLails Ih,' USl' of a "pleasant"
OdlH In higl\l'r concentration than lhe
offensiv,' Unl'. The odol' lhat is slrongl'r
hides or disguises the weakl'1' one. This
Inay not work too well ov,'r long pcriods
of 1 in1" for lwo reasuns:
1l i~ difficult to k,'"p al1 ,H"'u1'ale
h,d,lnc,' of !'l'LIll\'" slr"l1gth bel"""l'!)
j Ill' \)t!l) r s.
'I'll" "I rOl1g,'I' odol' IndY 1",,'Oll\(' ol"j",,-
(,,)11.11>1,' it~,'lf ,!CIl'l' :lI1Y 1"l1glh of lil11<'.
1\
(">l1111l'J';!cliOIl 111ak,'s liS,' of III<' pll<'I1n, OV("-. OJ' aboul tl1(' ooorif,'rous
d 1"',( bv \11l';'I1~ of calibr,llc'd alo\11iy.ing
ll()z:~I('s.
1'11,' CO'\l1h'J'dctiint \',lporizes lo be in1-
n1 l'd i a le 1 Y e f fed I V " ;, sit com bin" s wi I h
t 11(' ,\ i ,. st ,','''\11.
'I'het.t' is no unlvt'r~;lJ 0<101' ('()ltnlc'l"-
,J( 1,'111: sl"'<: i.d fOl'1nlllas ;t,'" I"'qui \','d
1'0" ",\('11 gl'oup of 'Hlors,
n,lor i'l'lHIIICllig gilS"S whicl1 111<'y 1)(' loxi,'
1\1' 11,11'1111'>11 10 pldnl illId ,.lnill1,ll Iii,' shoill"
"" 1 h,' I "", II ,," "y 111" ski n g I> I' ('(" II 11 " 1', Il' tin g .
I)
1'111' ()(!Ol' l'Ollnt\'f':ll't.lnt.s tl~->I'd in \,,'url" areas
11)\1,,1 111>1 I", (""il', ;,11l'rglc,
i II r tel 11 nn, L U I "
I' r l' \ ) r " ~) S 1 \' t'
" 1-: I I.: I: 1<01 ( , I:S
( It" 11 1 I ,,' ,. s . L. 1\, W h " !'\' n" e s A l r 1-' 0 Illl-
lil>n (,I>nll' ["1'0))'. l'ap,'r pr,'svnl,'d
~.io\"'J)]I)(' I' 1 S. I,)I,S <11 Ll1<' Na! Innal Con-
k""I1''!' 1>11 Ai I' I'nllution, Wi1shin~ll>n.
I),
t'
I,'
2
F:del en, W, E., and Clark, H. L. Odor
Control in Los Angeles County. Air
Pollution Control District, County of
Los Angeles. Publication No. 27,
3
Discussion of Coffee Roasting Process.
Air Pollution Control District, County
of Los Angeles.
4
Th.. Burning of Combustible Materials
rn>m Car Bodies. Morse Boulger
I),'slrlldnr Company. Bul1etin No. 141.
Ma,'Itrict, \.:ollnty of Los
An~('l('s, Paper SI)-4.
(,
st('nbuq,;, 1<, L. Control of Atmospheric
I
-------
Section Seven
COMBUSTION
Control by Combustion
III
-------
CONTROL
BY
Darryl J. von Lehmden
COMBUSTION
INTRODUCTION
Hany nf>,,1n lc compounds released from manu-
Llctut-ing op,'rations can be converted to
innocuous ,'arbon dioxide and water by rapid
,»)"id.\tion--combufltion. Three rapid oxidation
ml'l1lOds an' nsed to dE'fltrL'Y combustible con-
Llminat,",s: j) furnv.:11uatC'd in more detail helow:
II
Tempcl"at url'
EV"J'Y c'p,uhustlhl,' sub~tallcl' 11IlH n minimum
I~tdtio" tel1llH'ratun'. whldl must bl' at-
taint'd, nr eXl'l'~'deJ, In tIlt' presence of
nxygen, if comblls t ion is to ensue under
the given conditions. 'This ignition temp-
erature may be defined as the temperature
at which more heat 1s generated by the
reaction than is lost to the surroundIngs.
The ignition temperature for flow combust-
ion of combustible substances cover a large
range. as indicated in Table 1. (1)
- - - u . - --. -.- .--- -- - ---- -------1
11..1. von I.l'hmdl'n
Chell! lea I I';nl~ i nel' r,
(lfflcl' pf ~1an;>(lW('I' Ikv.'lop"H'nl.
Natio,,:,1 1\i,. /,,,11111 ion COlltrol !ldmlnl"tr;~ti(l~- .
PA. C. ~O,I. II . () )
The ignition temperature of the gases vol-
atized from coal vary considerably, and are
appreciably higher then the ignition temp-
eratures of the fixed carbon in the coal.
The gaseous constituents in the coal are
usually distilled off, but not ignited, be-
fore the ignition temperature of the fixed
carbon is attained. Therefore, if complete
combustion of the gases is to be achieved,
it is necessary that the temperature of the
effluent gases be raised to the ignition
tempera ture of the gases.
The same principle applies to the complete
combustion of any mixture of combustible
substances. A sufficiently high temperature
must be achieved which will burn all the
combustible compounds. To achieve such a
temperature it may be necessary to add
auxilliary heat to the combustible-laden
gas stream (e.g., via a gas fired burner).
Since the reaction rate increases with
temperature, temperatures considerably
above the ignition temperatures of the
combustible may be necessary to accomplish
complete combustion in a reasona~le amount
of time. .
B
Oxygen
Oxygen is necessary for combustion to
occur. The end products of combustion de-
pend on the supply of oxygen. When methane,
for instance, is burned with too little
oxygen, solid carbon results thus:
Ch4 + 02 = C + 2H20 + Q (heat of reaction)
The solid carbon agglomerates forming part-
icles of soot and smoke. If enough oxygen
is supplied, the carbon is burned to carbon
dioxide, thus:
CH4 + 202 = C02 + H20 + Q
Here, then, it is completely burned, no
solid is set free, and hence, there is no
smoke.
When carbon is burned with an insufficient
supply of oxygen, carbon monoxide results:
1
-------
Control by Combustion
. - .---- ---.-- - -- ----
FLAME IGNITION TEMPERATURE IN AIR*
(At Pressure of One Atmosphere)
Table 1.
Cumbustible
---~._-_._----- -- _._--~-------
Sulfur
Cha rco,d
J'ixed carbon
(b i l \1mino\1s ,'oa I)
Fixed carbon
(semibitumlnous coal)
Fixed carbon
(anthracite)
Acetylene
Ethane
Ethylene
Hydrogen
Methane
Carbon Monoxide
Kerosene
(;..soline
---- --- ------- --- -- --- ----- -----
Formula
TemperatureOF
S
C
C
470
650
765
C
870
C
840 - 1115
C2H2
C2H6
C2114
112
CH4
CO
580 - 825
880 - 1165
900 - 1020
1065 - 1095
1170 - 1380
1130 - 1215
490 - 560
500 - 800
:~ t: t- I)..
2<:0 + I)
*Roundcd-ouL values and ranges from various sources; a guide only.
I [ elhHlgh oxvgcn is 'Ivai] able, then carbon
d ("X ld,' re,;u I ts:
C t- (I 2 ~ co 2 + ()
'1'1". chemIcal ["('a<:tillns which occur during
the> cumbu:otJon of m'tny ~<1seous compounds
,Ire shuwn il) Tahlp 2. (1)
To '!"hieve comp.lete combustion of a com-
bustible compound with air, a Stoichiomet-
ric (theoretical) quantity of oxygen must
be available, The quantity of air which
m\1st be fllrnl~,hed to obtain theoretical
complete combustion for many combustible
cumpounds is shown in Tahle 3. (1)
It Is necesHary, however, to use more than
the theoretical air requIred Lo assure suf-
ficIent. oxvgpn for cumplete combustion.
Excess :1 it' ,,,old d not hl' rt'qui rpd i. f it were
I'''s:; [hI., to have ['very oxygen molecule
,'oml>1I1<' ,,,Ith the combustibles. TIll' amount
,,( l'~""SH air added to Insllre complete
CUllltJlISt JOII mllst I", ill-Itl aL .. pructical
IIIlnimlllll to ["(-dllce the stack heat losses.
I{l'all~,rlc V.dUl'H of eXCef<8 nir necessary
to burn vallollS fuel 11["(' given In Table
I.. (l)
c
'l'11I1e
A fundamentdl Jactor in the design and per-
2
formance of combustion equipment is the
time required for combustion of a particle
in relation to the residence time in the
equipment at combustion conditions. The
residence time (at conditions conducive
to complete combustion) should be greater
than the time required for combustion of
the particle.
The time of residence depends primarily on
aerodynamic factors, including size, which
are arbitrarily set in the design of the
unit. The time of combustion is controlled
by the temperature and aerodynamic factors.
The time of residence, then, becomes a
question of economy; namely size versus
temperature. The smaller the unit, the
higher the temperature must be to oxidize
the material at the time of contact.
D
Turbulence
Not only must the oxygen be supplied, but
it must be intimately mixed with the mater-
ial heing burned so that it is available to
the combustion substance at all times. When
burning solids without turbulence, the init-
ial products of combustion act as a screen
for the incoming oxygen, and thereby Blow
down the rate of surface reaction. The
burning of gases requires a thorough mix-
ing of them with air; otherwise separate
zones between the gases and air will form
and they will escape unchanged or incom-
-------
Control by Combustion
pletely burned.
Through the proper regulation and control
of these four factors, complete combustion
can be attained.
Table 2.
COMMON CHEMICAL REACTIONS OF COMBUSTION
._------ - ---
Combustion
Reaction
--~-~~----- -- -
Carbon (to CO)
Sulfur (to 502)
Sulfur (to S03)
2C + 02 = 2CO + Q
C + 02 = C02 + Q
2CO + 02 - C02 + Q
2H2+ 02 = 2H20 + Q
5 + 02 = S02 + Q
2S + 302= 2S03 + Q
Carbon (to C02)
Carbon monoxide
lIydrogen
Methane
Ethylene
CH4+ 202= C02 + 2H20 + Q
2C2H2 + 502 D 4C02 + 2H20 + Q
C2H4 + 302 = 2C02 + 2H20 + Q
2C2H6 + 702 ~ 4C02 + 6H20 + Q
Acetylene
Ethane
Hydrogen sulfide
2H2S + 302 - 2S02 + 2H20 + Q
where Q = the heat of reaction
~----- ---------~------_.
E
Heat of' ComhuHtlon
III
TYPES OF COMBUSTION
The rapid oxidation of combustible com-
pounds results in the exothermic reaction
(evolution of heat). The heat evolved (Q)
is known 38 the "heat of reaction" or more
specifically the "heat of combustion."
A
Principles of Flame Combustion
1
Yellow flame
The principles involved in the development
of heat by combustion, generally accepted
as authoritative, were propounded by
Berthelot. lIis "second law," as applied
to combustion in furnace practice, is of
particular interest and may be stated as
follows (1): In a furnace (where no
mechanical work is done) the heat energy
evolved from the union of combustible
elements with oxygen depends upon the
ultimate products of combustion and not
upon any intermediate combinations that
may occur in reaching the final result.
The heat of combustion for a number of
substances is shown in Table 3.
A luminous (yellow) flame results
when air and fuel flowing through
separate ports are ignited at the
burner nozzle. Combustion occurs over
an extended area in the combustion
chamber, producing a highly radiant
flame. The expansion of the gases as
the flame progresses provides the
necessary turbulence, while a large
combustion chamber assures the neces-
sary time at the combustion tempera-
ture to complete the reaction.
2
Blue flame
A burner utilizing the same fuel, but
arranged to premix the air and fuel
3
-------
Combustion Constants
For IOO"~ Total Air
Heat of Comhustion Mules per mole of Combustible Fur 100'"; Total Air
or
Molecu- SI' G, Dtu 1"" Cu F. Blu 1"" Lb Cu Ft 1"" Cu Ft of Combustible Lb ('Cr Lb of Combu",ble
lar u.~ Cu Ft Air l.)rMs Nct Gro!'ios Net Required for Combustion Flue Products Required for Comhustion fluc Product..
No. Su bstancc Formufa Wcight Cu fl pcr Lb 1.0000 (High) (Low) (High) (Low) 0, N, Air CO, H,O N, 0, ~, Air CO, H,O ~:
- -.. I
1 Carbon8 C 12.01 14,093 14.093 1.0 3.76 4.76 1.0 3.76 I 2.66 8 N6 11.~3 3.66 ~ 86
2 H~Jrt'gc:n H, 2.016 .0.0053 187.723 0.0696 325 275 61,100 51,623 0.5 1.88 2.38 1.0 1.88 '7.94 26.41 34.34 8.94 2~ 41
3 O,~ gcn 0: 32.000 0.~46 11.819 Ll053 ,.,. I ..,-
4 ~l1rogcn (aim) N, 28.016 0.0744 13.443 0.9718
~ Car~n monml.ldc CO 28.01 0.0740 13.506 0.9672 312 322 4,347 4,347 0.5 1.88 2.38 1.0 '1'.88 I 0:57 1.90 2.47 157 1 '10
6 Carron dio"dc CO, 44.01 0.1170 8.548 !.S282 '7'J ....
Paraffin ~ncs
7 Mcthane CH. 16.041 0.0424 23.565 0.5543 1013 913 23,879 21,520 2.0 7.53 9.~3 1.0 2.0 3.99 13.28 17'-27 ~.74 1.~~ 11 ~~
8 Ethane C,H. 30.06 7 0.0803 12.455 1.0488 1792 1641 22,320 20,432 3.5 13.18 16.68 2.0 3.0 13.18 i 3.73 12.39 1612 24' I ~t1 I:: 'OJ
9 Propane C,H. 44.092 0.1196 8.365 !.S6\7 2590 2385 21,661 19,944 5.0 18.82 23.82 3.0 4.0 18.82 I 3.63 12.07 1< 70 2.'f9 16' I; 01
10 n.8utane C4H <) 58.1\8 0.1582 6.32\ 2.0665 3370 3113 21,308 19,680 6.5 24.47 30.97 4.0 5.0 24.47 ~ 3 ~8 \1.91 \5.49 303 I ~.c; ! 141
11 hobutanc C~Hp 58.118 0.1582 6.321 :.0665 3363 3105 21,257 19,629 6.5 24.47 30.97 4.0 50 24.47 3.58 11.91 15.49 .'lJJ I ~~ II ~i
12 n-Pentane CH" 72.144 0.1904 5.252 2.4872 4016 3709 21,09\ 19,517 8.0 30.11 38.11 5.0 6.0 30.11 3.~5 1 t.81 15.35 3< O~ , ~I} 11 "
13 lsope:ntane C)HI: 72. 144 0.1904 5.2~: 2.4872 4008 37\6 21,052 19,478 8.0 30.11 38.1\ 5.0 6.0 30.11 3.55 11 ~ I 15.35 J 0< I <0 'I...'
14 ~eopcntanc C,H: 72.144 01904 5252 2.4872 3993 3693 20,970 \9,396 8.0 30.11 38.1\ 5.0 6.0 30.\1 : 3.55 11.81 15.35 ~ u<. 1 "I) 11.....\
15 n~Hexane C,H.4 86.169 0.2274 4.398 2.9704 4762 4412 20,940 19,403 9.5 35.76 45.26 6.0 7.0 35.76 3.53 11 74 I'" 17 j U6 1 40 I' 74
Olefin 5CrI~
16 Eth:olc:ne C:H. 28051 00746 13.412 0.9740 1614 1 ~\3 2\,644 20,295 3.0 \1.29 14.29 2.0 2.0 1 \.29 3.4I:! 11.39 148\ 3.14 ] 2~ 1] N
17 Prop:olenc CH. 42.077 0.1110 9.007 1.4~04 2336 2186 21,04\ 19,69\ 4.5 16.94 21.44 3.0 3.0 16.94 342 II 39 1481 3 14 1.2~ II N
18 n~BU1.cnc CoH. 56102 01480 6.756 1.93)6 3084 2885 20,840 19,496 6.0 22.59 28.59 4.0 40 22.59 i 3.42 \1 39 14.81 ).14 1:!~ II W
I
19 lsobulene CoH. 56. to:! 01480 ,6.756 1.9336 3068 2869 20,730 \9,382 6.0 22.59 28.59 4.0 40 2~.59 I 3.42 II 39 14.8\ } 14 I 24 'I.\Q
'-:0 n.Pcntcnc C,H 70128 0.18~2 ~.400 24190 3836 3586 20,7\2 19,363 7.5 28.23 35.73 50 5.0 18.23 ~ 3.42 11.39 1481 ) 14 I 29 11 39
Aromatic SCrtes
2\ Iknzcne C6H6 78.107 0 2060 4852 :2 6920 3751 3601 18,210 17,480 7.5 28.23 35.73 6.0 3.0 28 2) i 3.07 10.:: 1330 3 ~)( 0 o~ 1022
" T oluenc CH. 92 132 0.243\ 4.1\3 31760 4484 4284 18,440 17,620 9.0 33.88 42.88 7.0 4.0 33.88: 3. \3 10.40 1 3.~3 J 34 078 1040
23 X~lel1e CoH.., 106.158 0.2803 3.~67 3.6618 5230 4980 18,650 17,760 10.5 39.52 50.02 80 5.0 3952! 3.17 \0.53 \3 70 -'- - 0 ~~ 1053
~I~ellaneous gases I
24 Acel~ Icne CoHo 26.036 0 0697 14.344 0.9107 1499 1448 21.500 20,776 25 9.41 1191 20 10 9.41 3.07 1022 I: )0 3 " 0 6~ 1011-
25 'apnthalene C. H. 128.162 0.3384 2.955 44208 5854 5654 17,298 \6,708 12.0 45.\7 57.17 10.0 4.0 45.17' 3.00 997 1'-: 96 34) 0 ~b ~ 97
26 ~1eth»1 alcohol CH,OH 32.04\ 0.0846 11 820 1.1052 868 768 10,259 9,078 I.S S65 7.15 10 2.0 5.65 II.~O 4 ~8 6.48 1.37 II' 4'111
I
27 Elh~ I alcohol CH,OH 46.067 0.1216 8.121 I 5890 ! 1600 1451 13,16\ 1\,929 3.0 11.29 1429 20 30 11.29, 208 6.93 9.02 192 1 17 0 ~3
28 AmmOnia ~HJ \7.031 0.0456 21.914 0 5961 i 441 365 9,668 8,00\ 0.75 2.82 J 57 1 5 3.3: 1.41 469 6 10 ! ~~ ~ ~ I
50. SO.
29 Su1fur. 5 3206 3,983 3,983 I 1.0 3.76 4.76 1.0 3'6 1.00 3 29 429 :2 00 3::'1
30 H~drogcn sulfide H.5 34076 0091\ 10979 1.18n : 647 596 7,100 6,545: 1.S 565 7 15 I 0 1.0 ~ 6~ 1.41 4.69 6 10 1 88 0 ~ J 4M1
31 Sulfur dioxide 50 64.06 01733 5710 2 2640 I
32 V.'a.lcr ...a.por HO " 016 00476 21 017 (I b21 ~
33 Air 2>< ~ 00;66 IJ 06) 1.000<'
'Carbon aDd sulfur arc comlJen:J as g.J~t'~ for r.lobl calculations only. :-';ok: This t"hle I> rL'prllltcd frolll Fuel Fluc Casn,
courtesy uf AmerlC,m ell> ASSOll,\tion,
All gas volumes corredl'd to 50 F and '30 in IIg Jry,
;.:o,[) 1",
~
...
-------
Control by Combustion
Table 4.
lISLIAL AMOUNT EXCESS AIR SUPPLIED TO FUEL-BURNING EQUIPMENT
Fuel
Type of furnace or burners
Excess Air
% by wt.
15-20
15-40
l'\llved ;:L'd l:O.1I
Completf'ly water-cooled furnace for slag-tap or
dry-ash-removal
P,11-tiall y water-cooled furnace for dry-ash-removal
Crusl1L'd C()al
Cyclone furnace
pressure or suction
10-15
Coal
Stoker-fired, forced-draft, B&W chain-grate
Stoker-fired, forced-draft, underfeed
Stoker-fired, natural-draft
15-50
20-50
50-65
5-10
10-20
Fuel-oil
Oil-burners, register-type
Multifuel burners and flat-flame
Acid sludge
Cone-and flate-flame-type burners, steam-atomized
10-15
Natural, Coke-oven,
& Refinery gas
Register-type burners
Multifuel burners
5-10
7-12
Blast-furnace ~as
Intertube nozzle-type burners
15-18
WOl,t!
Dutch-oven (10-23% througl, grates) and Hofft-type
20-25
BagaSSt'
All furnaces
25-35
IIlack Liquor
Recovery furnaces fur kraft and soda-pulping processes
5-7
-------- ------- ----- -- -- --- - - --- - - -~---_._------ ----
--
prior to delivery to the burner nozzle,
will produce a short, intense, blue
flame, permitting complete oxidation
'vithin .] confined space.
in any fuel-fired burner, whether it
is of the luminous (yellow flame) or
permixed (blue flame) type, substained
combustion depends upon maintaining
the air-gas supply to the burner within
the flammable range.
gases are released at energy concentra-
tions constantly within or above the
flammable range, their disposal can be
handled most economically and safely by
application of flares. However, smoke-
less burning of huge quantities of gases
by flares presents some serious design
problems. First, the flare must be suff-
iciently elevated above ground level for
heat and flame protection of adjacent
buildings and personnel. Flame must be
sustained at varying rates exceeding by
many times the operating range of in-
dustrial burners. These physical demands
prevent the employment of combustion
chambers.
B
Flare Combustion
All proccss plants which handle hydro-
carbons, hydrogen, 3/nmonia, hydrogen
cyanide, or other toxic or dangerous
gases Lire subject to emergency conditions
which occLisionally require immediate
re leas\' of lar~e volumcs of such gases
for protection of plant and personnel.
In allV pl'l rochcml cal process, hydro-
carbons pn'fll'l1t with 1 l1f'rt P,.\HCS. slIch
"" n! 1 rogl'n and cllrbon dIoxide, must
I,,' "0111. tnllollslv released in variablp
voiume find l'I)ncE'ntrnl Jon. Where lhesL'
Flare combustion is often characterized
by a luminous (yellow) flame. The lumin-
ous flame results when oxygen in the air
surroundi.ng the flame comes in contact
with the hydrocarbons by diffusion only.
.The luminous color results from incandes-
cent carbons which result from the
cracking of the hydrocarbon molecules.
5
-------
Blue-flame flare combustion can be ac-
complished by adding water vapor, under
proper temperature conditions, as the
gas is burned. A water-gas reaction is
set up, generating carbon monoxide and
hydrogen ",'hich assists in the production
of blu0 flame burning by removing the
llnbl1rn~d carbon. Combustion of carbon
monox id,' ,md hvd rogen resul ts in carbon
uioxid,' :mu watL'r. e)
C 1 11/1 ~ ell ~ H2 (w:Jtl'r-gas reactIon)
1/2U2 = C02
H2 + 1/202 = H20
Cll +
One design of a steam injected flare is
illustrated in Figure 1. (2)
steam jets
Ilare tip
~pilot tip
I lame Iront ignitor tip
'teom mandold
stearn
suppl y
I
''''.1
flame Ironl ignitor
-. tube
mixer
--- pilot gos connection
['0 pilot 2
- ,--,,-~~.;:':.:; pilot]
- .~ .~/
I <-,--~/
I I t/) ]-wroy plug volves
o pro "
'."/ gllrL' L.
STliM1 /N.JECTfON TYPE FI.ARE
II
C
Furnace Combustion
Whereas flares are effective in destroy-
ing waste gases which are released
continuously or periodically at concentra-
tions above the lower limit of flammability,
gases vented from industrial processes are
generally exhausted at concentrations far
below the lower flammable limit. At these
concentrations of gases, combustion in
an enclosed chamber is necessary.
Furnace combustion is commonly called
'"direct flame incineration", since a
separately fired burner is normally em-
ployed to sustain rapid oxidation. The
flame, per se. has no influence on the
reaction except as it provides the time-
temperature - turbulence factors.
Since "the three T' s" allow considerable
latitude in design, numerous combinations
of the "three T's" will result in com-
plete combustion. Generally, however,
furnace construction costs required a
practical limit on holding time of less
than 0.5 to 0.75 seconds. Residence
temperature may vary from 9500F for
naphtha vapors to l6000F for methane and
somewhat higher for some aromatic hydro-
carbons.(2) Higher percentages of inerts
in the gas stream which act as oxidation
depressapts will demand higher tempera-
tures. (3)
A diagram of a waste gas and odor in-
cinerator is shown in Figure 2.
- ----.
I
scroll heater
exhaust
.0
holding
chamber
END ELEVATION
SECTIONAL SIDE ELEVATION
.----
Figure 2. DIAGRAM OF A WASTE GAS
AND ODOR INCINERATOR
-------
~~ ----. ~ --
--- -----
- ---- ---~ - --.---
Taule 5.
INDUSTRIAL APPLICATIONS OF CATALYTIC COMBUSTION
-.-.-------
~proxrmate tempera-
ture required for
catalytic oxidation
. ------- - --.
11hi\lstrLd prucess
Contaminating agents
in waste gases
,\sphcll t U:dd i,z i.ng
- ---------~----------~---_.-
Aldehydes, Anthracenes,
IHI Vnpors, Hydroc:lrbolls
600° - 700°F
r::~~~\)\, 'q :1("1< ""f,.".
112' (:1\, CIIII' Carbon
(',Ita [,'l i v Cravk ing
Units
CU, lIyJrocilrbolls
Cl1rt= UVl~ns
Wax, Oil Vapors
F,'rl11,lldehyJe ~1f~;.
H2' CH4' CO, HCHO
HNl1 j ~lf f,.
NO, N02
NeLd Litl]l1~~r:Jphv
OVl~ns
Solvents, Resins
l1ctyl-pllf'l101 Mfg.
C6 fI5011
*1200° - 1800°F
650° -
800°F
600° - 700°F
650°F
**500° - l200°F
500° - 750°F
600° - 800°F
I'hthalil' Al1hydr idL'
~1 f I; .
Malpjc Acid, Phthalic Acid,
Naphthaquinones, Carbon
Monoxide, Formaldt'hyde
600° - 650°F
1't1I\",thvlcll" Mr~".
Ilydrocarhons
]'rilll ilH~ I'I-l'~~;~l'~~
Solvents
\'.1 rl1 i sl, {'l It,l\ i 'J~',
IIvd rUL'.II:-holl V"j)()]':-1
h'irl' Cl1.lljl~~', .lnd
1':1\,1111<' I i.1\~', I)Vl'l\:-1
SoIVl~nLs, Vilrnis],
500°
l200°F
600°F
600° - 700°]>'
600° - 700°F
- - ---- ----- --- -_.---~-
k '!"'01jH'Llll1re;, In l'X,',''';S of 12UOoF rpCJl1ireJ to oxidize carbon.
,>,\ [{{'dueing clt01o,.;plH'r!' !'<'quired.
IJ
Cntalytic Combnstion
Cat.d,ytic comtJus ti 011 i:o the lowest
Ll'mpl'rature method of rapidly oxidizi ng
comhl1stible 1'.3:-1"';
-------
. ,.., - ------,
-'---
/
/
exhaust fan
inner metal liner
inlet
stock outlet
c ol1l1ec I ion
mineral wool
insulation
f,,,eh,'ol
burner
,outer metal jacket
catolyst elements
access door
- .- -- ----
I:; gu,','
\,
Ci\TflLY'I'IC COMHII~TI()N SYSTEM INCLLJD-
I N<: I'\{FIII':AT IIUltNER AND 1':XIlAUST FAN
("I.'\vII,' ".1II1bIlSllol1 Is gl'nl'r,J!ly /11'1'11-
,nb I., \JIIt' 1'" fl,,' f.1I lowing ('onoil lUnA
IIPP]Y: I) 'Jhl'n' thl' g"s stn'am to be
handled c0I11"I,,,, vapurl~:ed or gaseous
.'umlll,slible> materials, clno 2) where there
Is no large amount of oust, fly ash, or
other solio inorganic material in the gas
st rpam.
Catalytic systems are designed to prevent
condensate formation in exhaust equip-
ment. The exhaust fan in a catalytic
system is located on the hot side of the
system so that all vapors passing through
II an' above the condensation temperature.
A tvplcal catalytIc
(~l1ploylng ~ prehe,lt
FiguTL> 3. (._)
combustion system
burner is shown in
11".11 ('vo]vI'd by [11(' ('alalyt'lc oxi<1atiol1
(':," "I so In' lIt','d to prt'hea l the gas
sl"""I1I, Fj~',lIn' 4(1.) ~"1(1WR a !reat ex-
.'II,lIlgl'" ,\Ild pt't'lll'1It burner arrangeml'nt 1.0
heat lhl' 1'.;1,,; "I ream to the catalyl Ie
Ignltlou tpmp,'r.I!lIrt'
II
----- -'
--
heqt
exchanger
exhaust
t
-
1
from process
Figure 4. CATALYTIC OF COMBUSTION SYSTEM INCLU[)-
ING HEAT EXCHANGER, PREHEAT BURNER
AND HEAT rAN
IV
SELECTED APPLICATION OF COMBUSTION TO
AIR POLLUTION CONTROL
A
Flare Combustion
1
Dimethylamine odor
the manufacture of
detergents(S)
control during
soaps and
Providing new and improved products for
the consumer requires new processes and
new chemical raw materials. The manu-
facture of new products by a soap and
detergent company required the use of
dimethylamine as a raw material.
Dimethylamine NH(CH3) 2 is a
gaseous material at 400F and atmospheric
pressure. The material is a first cousin
of ammonia (NH3) and at concentrations
in excess of 100 ppm the odor of this
amine is nearly identical to that of
ammonia. As the amine concentration
hecomes diluted it takes on an odor
resembling fish which has been in the
sun too long. As the concentration
falls below 100 ppm the fish odor be-
comes predominant over the ammonia odor.
-------
- - -----'--'----- -
..----- .'_h
..-- - ----- ---- --
--------l
I
i
I
I
discharge to stock
J
blower
\
fume
incinerator
C.. ,. ."'C', ..,." ;." .. :a. ' ..., ,,' l"
. . .' , .. " ' , . (;JJ'
. ,
, '.
, ,
. , " :. ,~ . -; ,
-"J'.... "
---
. ',' ..., '" -. ...... .'.
t
t'~.:..
'-.
open kettles
t
OIr
..,...1
closed kettle
- - - -. -- -
---.,----.--,------..
---.---
F i ~', I: It'
'.
1,1\)\'11'1" 111
I'" '"II': Cf)MIIIJST 1 ON SY:;TI':M F(lR I'Ar NT AND VARNISJI COOKING
T\\ pr"\I!d\' 1-{'1 il'f 11-0111 Ihi-, I i~...IIY od,1I"
! (I) t't'~; i lil'lll 1;1\ ,Ir(':l~~ :)r,()() [l'l'l I-rum l1lt'
pI :111 t, ,1 lI\l't I1tHI Wd,<-: ILl't'dl'(1 l () dC's t 1"1IV t ll(,
dimt,tllvJ;unint' L'!lI[:--::..;iun"~. TllI'spJuLiol\
II) '"hi!-. udt")[" I'r{)hl"1l1 \..'.1"':; dj)r,1inl'd tllrrHlgl1
till' ","", "," ,J 100, I ""t I I'll' "t ;,Ck. Tile
,ll1!il1l~-I~llf'-: lp .1S:;II1"~' i}~tlitic)\) (It ,Ill ('(llllbll~i
I i h 1 ,.., 1'" 1 ",I",.,J I I "I" ,I... ,: I,ll'" , '1'111'
I I '.II I! II, I, !)I '(,'11 I ';1111 dtc, I j' :~; t J .11'1' wI! it 11
t t ,111 \', >:; I 11 t' . \. 11'1 I" I I ,II 11'10 l; t'V 1'1., I j ~ 1 r<'<"'" 11.1 v'" I)('('n ro.dll('t'd by
t',lpid oxidlL'
g""l'S ,'rnjtl,'cI Irolll till' Id:Jck Ij'llior.
In the hurning of combu6t.llde vapors
from pr,j nt ilnd varnish cookers, adequate
consideration must be given to prevent
fire or explosion i.n the kettle as a
9
-------
III
result of flashback through the vapor.
Safeguards can be achieved by diluting
the vapor concentration to less than 25
percent of the lower explosive limit
and by maintaining gas velocities in the
ducts well in excess of 20 feet per
second, the rate at which flame could
propagate along the duct.
fatty acids, furfural, methylamine,
pyrole, acetic acid, acetone, ammonia
pyridine, and hydrogquinone.
II fU1I\t' (VclJHlI') l'01l\bustlon system for
i!1l'inerating vapors from paint and
v:lrnish rookers is shown in Figure 5.
4
Furnace combustion is presently being
employed to incinerate the combustible
gases from coffee roasters and to re-
duce the odor per se.
Vapor and particulate control from a flue-
fed (apartment house size) incinerator (9)
A c.'rt'ectlv pt'()portionpd and well-in-
SULl ted furnarc requ.i rE'S i1 fuel input
bel\"l'l'n 600 i1nd 1200 BTli per hour per
gallon of processed ha tch. In some
I'rocesses. enough vapors are produced
t.) appreciably supplem1'nt the regular
fu",1.
Flue-fed incineration is a batch-type
operation. To effect complete combustion
requires that the correct amount of com-
bustion air (Stoichiometric air plus some
excess air) be supplied during each seg-
ment in the combustion cycle. Normally,
however, batch-type incineration results
in a deficiency of air after the refuse
is charged and too much excess air during
the burn-down portion of the cycle. The
result is incomplete combustion of com-
bustible gases and particulates (solids).
J
Odor control from coffee roasters (8)
1~e romhustible~ in effluent gases from
coffee roasting may be present in con-
centration ri1nging from 0,17 to 0.27
grains per rubic foot, depending upon
the lVP" of roastl'r
-------
---
. -- ----"-- --
--~---- -.---
R?
Fi>;urL~ 7.
return
.6
LITHO-OVEN
CATAI.Y'l'1C OXIDATION OF SOI.VENT FROM METAL LITHOGRAPHIC OVENS
.... .".'.--'-- -------------.-.--
c
CaLlly t ic Combus t ion
l C,!talyli,' lIxfdalion of lithographic oven
v''I1('rs (4)
C;tt,!lyt ix L'omhusllon Is uSL'd in many
industri:tl I'rncl's,,,:,S to destroy odors
.md conlamin,l11l g;ts('s. Among the processes
111 which c;]lalvllc l'xld~.. I1l1'lha'I(') or r<'al'lIvl' lUl'l (e.g.,
C;1 rl"H' lIIonox f dt') W f t h lIl(' WIlH ll' gllSl'/! /lud
* Table ')
passing the gases through a catalyst, the
following reaction takes place if the
reaction goes to completion.
(nl)NOx + (n2)HC = (n3)H2) + (n4)C02 + (nS)N2
This reaction can be made to proceed at
comp3ratively low temperature (SOO-1200°F).*
The amount of free oxygen contained in the
waste gas stream presumably influences the
case with which the reaction can be com-
pleted. Obviously, when the waste gas
stream is entirely devoid of free oxygen,
then oxidation of the hydrocarbons can occur
only through simultaneous reduction of the
nitrogen oxides to a lower oxidation state
or free nitrogen.
A schematic of
tern for nitric
in Figure 8.
a catalytic reduction sys-
acid waste gases is shown
I
exhaust to atmosphere
exhaust fan
catalyst bed
recycling
gases
prehea t burner
reduc i ng fuel
process waste gas
- - .------ -- ------
FJ gurc 8.
SCHEMATIC OF CATALYTICAL R'mUCTlON
SYS'mM FOR NO
x
11
-------
REFERENCES
1
Babcock and Wilcox Co. Steam-Its Genera-
tion and Use. 37th Edition, Chapter 4,
L9bJ -
2
Stern, A.C. Air Pollution. Academic Press
New York City, Vol. 11, Chapter 32.
3
Coward, /l.F. et a1. U.S. Bureau of Mines-
Bulletin 503. Vol. 4, 1952.
4
Oxy-Catalyst, Inc. Basic Engineering
Principles of the Oxycat. Berwyn, Penn.
5
Byrd, J.F. et a1. Solving d Major Odor
Problem in a Chemical Process. JAPCA,
Vol. 14, pp 509-516. December 1964.
6
Hendrickson, E.R. et al. Black Liquor
Oxidation as a Method for Reducing Air
Pollution from Sulfate Pulping. JAPCA,
Vol. 14, pp 487-490. December 19b4.
12
7
Stenburg, R.L. Control of Atmospheric
Emissions from Paint and Varnish
Manufacturing Operation. U.S. Public
Health Service. ~.A. Taft Sanitary
Engineering Center. Technical Report
A58-4.
8
Anon. Discussion of Coffee Roasting Pro-
cess. LAAPCD.
9
MacKnight, R.J. et al. Controlling the
Flue-Fed Incinerator. JAPCA, Vol. 10.
April 1960.
10
Donahue, J.L. System Designs for the
Catalytic Decomposition of Nitrogen
Oxides. JAPCA, Vol. 8, pp 209-212, 222,
November 1958.
-------
Section Eight
ABSORPTION
Absor'uel'~;
A Ou:Ldo to Scrubhcl' 8elcc.:tion
I\bsorpU on ]I:(l1!1 pmc:nt :
S('lectecl Applications
-------
AB3) RBEHS
I NTTt1 I JlICTT()N
f\
f\bsorhers (scnlhbers) refer to t.he
gl'lIeral c1assi fication of tlevicos used
ill air pollution control to remove, treat,
or moJifr one or more of the offending
gasl'()US, \)1' V3porous, cons t i tuellts of a
g;I" ,;t ream by hnllging the gas stream into
int irnak contact ('lith an ahsorhing I iquitl.
1\
1;01' ~;crubhillg (;lbsorhents) liquors, many
typc', III' solutiolls may be used containing
neut ra I, a 1 ka I i Ill', or ac i d ic reactant
111.'ltl'riah.
II
I I QIIIIJ i\1\:-l) I~BI 'N'IS
i\ J. iqu id /\bsorbents May I\e Classified !\.<;:
Non-reactive liquitls
:;
React i ve Ii qu i os
fI
Non- react ivc Liquid
,\ nOli-reactive 1 iquid is a simple
o.,l11vcnt whidl dissolve's the vapor, or
re lea~;es it, with no chemical react ion
i nV(1 I \'t'd.
Non' react ive' I iquios that arc usetl arc
rrl'quently water or a heavy carbon oil.
c
111';ldive I.iqllid
/\ reactive I iquid is one which n.:move5
the g;lseous pollutant through a chemical
reaction, transfonning the polllitant to
a 1('55 offens i Ve' form.
'thert' arc two types of react ive I iquitls.
a
Regenerative absorbents
h
Non-regenerative absorhents
;
Non-regenerative' ahsorhents
a
'Ihese absorbents arc i rrevcr~; ible
conve'rteo antl mus t he' 0 i sea rued.
1'/\. ('. gc . ~.. II . ')9
b
They arc more expensive than re-
generative liqui~<; when large
quantitks o[ gas arc treated he-
cause of the necessity for steady
replacement of liquid. However,
for installations of small capacity,
irreversibly rcactive~i~<; may
he cheaper because no regenerati ve
or recovery system i5 needed.
4 Regenerative ahsorbents
a
111OSO 1 iqui lis relea~e the gasC'ous
pollutant reversibly by application
of heat or steam.
h
Mlen large quantities of gas must
be treatetl, economical considerations
favor the use of regenerative
absorhents.
1)
IIigher investJOOnt costs of the
regenerative system are amortized
quickly and offset by low costs of
makeup absorbent.
Salability of the recovered
vapor may counterbalance the
amortization cost entirely and
permi t it profi t. llowever. i f
the vapor has no sale value, its
disposal in concentrated form
may create a new problem in
pollution control, either
in air or water.
2)
D IJcs i rable Characteristics of the J\hsorlJCnt
I
lhe absorbent must remove the offentling
vapor down to a pernrissible or
tolerahle, concentration in an
economical installation.
2
Desirable characteristics include:
-------
1\ bs 0 rl)(' ['S
a
I ,ow vulatility
II
I ,at' h: or 0<.101'
c
N Oll-t' or ['osivt~ness
d
:-;tal>ilHy
t'
I,ow viscosity
I,ow f'lamnnl>ility
g
I,ow ('ost
I'; :-;tJlIlI' Typk;1l I\bsorbcnts
1'0[' suil'ur' dioxick I"('moval:
a
I\mn1OIlium sllHik
"
I\mmollium suil'at(.
"
I )io1('tll,)' lamillt'
d
Sodium bo['att,-lJoJ'ic acid
'J
I"OJ' tlu' 1'(' rnoval of II~S:
;1
Sodiun1 plH'lIolak
"
M, mo( ,tlla noli lInin('
I )idll:lllolarnill('
d
T,' i( 'th:11I01:"11 illt,
"
Tripot:ISsilll1l phosphat(.
Sud illlll (':1 "),OIl:1t"
..
I,'",' lhl' ",'muv:ll or so;!
:r
S( );: is 'uJk S,IlII"'" ill w:rt.,'"
h
IloWI'VI't', S( I,. i;: liquid ;lIld ,':-;isl;;
:IS Sllhll!i,"'O';':, j'/,('d d ,'upl('1s.
I' 'I'll<' ,';It., :11 which LIlt' KO lubl(' gas p;I~;S"K
JIlt.O s'>!lIl.ioJI is usually slow. TIIt,/'t.ror't.,
tlJ<' (absol'!>il1g) liquid rn list 1)(' I!.lwsi('all,y
p""p:\I'('d so Ihat tlw I:Irg('st. possihlc'
KlIt'I':}(';' ';;111 Iw ('xpoH1:d to tll(' gas.
~
. ---- --..- --.- _u~-
-. ---- -- --.--.. ----' -.-.- ._-
Mecha.lical methodf:l employed in
abHoI'ber'H to accompli!:lh this include:
a
Packing mate rial::;
b
Bubbling
c
Atomization
d
Agitation
III
TYPES 01'- ABSOIUmB.S
A Typ('s of Ab/:>orbcr/:> Used in Air Pollution
Abatt~mcnt Include:
Packed towc' ['H
2
Plate towe I'H
:1
Sp ray towc I'S
4
Agitated tankf:l
G
r ,iquid jet sc ['ubLe r'::;
B Th(' abHor'bing liquid iH physically prc-
pa['e<.l HO that the la['g(,Ht possible !:Iur'face
h; ('xpOI:wd to the gaH as follow/:>:
AI>HOI'l)(' t'
Mc.thod of AbHorb('nt
,- -- ~> ~<:ya~ation
Pa('king matl'l'ial
-----'-
P;1<'k('<1 tOW(.t'
Plate' toW(~ r'
Bubbling
Atomi:t.:1,tion
Sp I'ay toW(' t"
/\git:1(c' TOWJo:lt (I"igut'e 1)
1\ 'I'll<' pad«'cJ toW(~[' conHiHtli of a v(.,.tkal
1'11(,11 whic:h iH fill<~<1 with a Huitah1<' p::wk-
ing lI1at(~ t'ial.
Thl' liquid flOWH OV('f' the Hul'l'a(;(' of tlw
packing in thin nImH, th(.t'('hy [H'('Hent-
ing n lat'ge !ic!uid su['fae(! in contact with
the' gaH.
-------
r
I
I
I
I
I
UOI./IO.
PACKED TOWER ABSORBER
IV~NI
-- -bli¥IftIlUToII
I'''I;I\INO
t;lIra~o.,lr
I.'iglll'" I
1\1<>:.1 I"IV"I'~; :11'(' 11111"1"'111'1"'111 !'low 1:-: 1)1'('1""'1'('<1 1.11
"'11\'111"'1'111 I'III\V 1)('(';'11:-:" ;d, lilt, 1.111'
<>1' lilt, ''>WI'I', lilt, I i'l"i1,1 i 011
1\ II "\"'11 1"1"1<1 ,
/\bsodH' ,'I-J
Vapor out
I .i'll/it! "" I'ubk fool of
p;1(;killg I'allg"s f"om I!) sljllarT 1'",'1. 1.0
21JO SljU;II'(' 1',"'1.,
-------
TOWER PACKING5 EMBRACE A WIDE
RANGE OF DESIGN.
EJEJu~
--
--
--
---
nll~~
---
---
--
--
I"iglll'" :i
MIoKE
UP
E
~IS
YN"OR LAOI!:N
ABSORBER
1/116 I RE8OL£R
M
I"iglll'" 4
TYPICAL FLOW SHEET FOR ABSORPTI~ SYSTEM WITH R£cKNERATOR
"('g'('IH'I':dol' tllI'ougli w!tn'li it 1;1111',
,L:lv illg up ,I portio 11 or ill' ahl'ol'!wel
IO;I!i ,)i' oi'r"l1l'iv(' v;q)OI'.
I>
'I'll<' v:\p()I'-lael"1I al>l'ol'llI'lIt 1I';lv('1'
Llu' I>otLolIl or till' T't'gl'II"I'atol' allu
P;I,C;"';";i to it l'l'I>oil., f' wlJ(' 1'(' it il'
11I',,1<-1! ,I lid tI\I' 1'('III;!ill1l1g ol'l'('lIl'iv('
V:I,.O\' vapo!'i",'d.
I) 'I'll(' :1I)"';OI'I)('lIt r"'llIail1jllg il' ('ool(,eI
;IIleI ",'tUI'IWei lo t.lJ(' top or 1.111'
;1!)l'ol'III'I' :1;; 1":111 aIJl-\ol'llI'lIl.
~) Thl' vapor' (['cleascd in thc I'(!-
boile r) passes up the ['(!gcnerator
towel' and slowly strippt'd of any
absorbl'nt it may contain by th..
downcuming liquid from thc
al>so['bc ['.
:i) Thl! of1'enHivl' vapor lcav('s the
top of thl' rl'gcncrator C'onccntra-
l..d and rl'ady for conv('rsion 01'
diHpoHUl.
-------
v
['1,1\'1'1-; TOWI-:lt<;
A
111[ 1">1II1<'tloll
\\111"11 I''''aliv('[y il1so[ul>l,' orl't'nsiv,'
g':!s,'s a['(' to bt' absnrL)('d, tlWI"!' should
IH' go"d lud)ul"I](," il1 tll!' Jiquid ph;IS(',
:\
1111d,' I' such ,'olldjliol1~;,
1)1" IHkd th:il LlII' g;lS 1)('
tlll'l)ugh till' liquid,
il is ,','com-
huhl>l,'d
I,
'I'u ;1('('(>llIpljsl, SII<'II al1 op"I'aliol1,
pl;lt.. low"I'S :11'(' us,'d.
~
Tit., lwo I1I1)sl us,'d lyp"s of pLltt,
low,...,'i :\"":
:1 Sj,'\", P 1;11", 1.'>'1)('
I, I\ul ,I" (' ":", 1'1:liI' ty 1'('
I; Si,'\(' ['1:11,' Tow"I' (/o'iguI'" ~I)
SIEVE PLATE T~
,-~ LIQUIQ
_'0'£1," /1Y---''= I. ~LlQUID 00"" ,'.!rl,
"., 01\ .-. 'UL CUP.
VAP'Oilt./ ., .
, . - i - - - - - ,. 'I[V[ "'-AT[
I ' - ---.
____~L - ~ ,TOftIl .'H(LI....
"AS O~ VA POll /
"igul'O' [,
"'1,(,,;,, l(lw"I'~; ,'ol1sisl or.. v'Tti,:1I sll<'11
111 wi I i (,II "I',. I II 011 IIii'd ;1 1 :II'g" 111.11111)1' I' ur
("lu;IILy spa,'('d ,'il'('III;1I' IH'I'l'ol';ll,'d
( ;-i I" \ ,,) 1'1 ;11" S .
,\
'I'll<' Slt'V" 1'1:11(' P"I'I'OI'"UuIIS ;\1'" I lu"
to :i la" d i:II))I'I,'", 'I'uI:1I al"';r or LlII'
1)('I'I")f';\lioI1S ;\1'0' :d)()(11 IO':\, or ille'
1 01 : II 1": 11 , ' ,
"
'\1. 0111' ~;id,' or ":IC!J I'bt.(, ;1 ,'ol)(luit
,':11 kd :1 dOWI1 spout is I'l'ovid,'d to
I'''ss 1.111' lilJlrjd J'1'OI!l ill<' pl;rl<' to th('
1'1:11.' 1)l'I(lw.
At. tll<' "I'f!0sil,' sid,' or 1.Iw pl:1t" :1
silllilal' ("Jllduil I','('ds liquid I'r'orn tll<'
1'1;11" :d)()v(',
!\ bsoc'bp r'!>
2
Gas,'s 01' vapor's I>ubbl.' upwar'cj through
thl' Liquid I:)(';\L auov(' t~ach platt'. Thi::->
pasHag(' of gast's th I'ough tht' Pl'r'('or-
mations prl'vent::; Liquid f"om paHsing
Ihr'ough Ih(' ho1<'s.
(' BubhL('-cap Plait. Tower ( Figure 0)
1'h('st' towe 1'1'; conHist of;} ve £'tical shell
in which an' mountl'd a largt' number' of
t'
-------
A bso1'lH' ['S
- -, - - p ..- --------
VI
PACKED TOWISltS VS. PLATE TOWE;US
A
For absorbing corrosive gases and vapors
it is us ually more economical to construct
a packed towe r.
H Tbe pac ked towe l' will ope rate unde l' lowe I'
prt'ssur"l'drop, for equal operating
conditions.
(' l,iquid dist['ibution is less acute in plate
tow('['S tlu.. to the cross-flow of liyuid.
Th~IS, l/}('['(' is less tendency for channeling
of g:1S in pl:1k t.owcr's.
/) r';nl.l';lillllH'nt. difficulties are mor.' s..dous
in p1;Ik t.OW"I'.
I'; PLlk tow,' ['S usually can handl(' high.~r
liqllt11 [':\t,,:-; without flooding.
I" '1'11<' plat., tOW"I' usually rl'pr'('s('nt8 a higher'
initiallllv('stm.'nt.
VJ1
SPI~A Y TOWE It..S
A Intl'od w.tion
Wlwil highly solubl.. off.~nsive gases arc
to be absol'l)('d, there should b.' good
lud)ul,'nc(' in th., gafwouH phas., (around
till' outsid,' of tlw liquid dropld>.
:1
'I'1H'rdo['(', spraying the liquid
thl'ough tlw gas is ('mployed.
b Sp['ayin,~ iH a('complishctl by Ul:iC of
Spt.:!'y tow., ['S, or chamlwrs, of
vadous ,h'signs.
1\ Types of Sp[':lY Im;tallations
or th., many variations, two types a['l~
shown in Figure 7 and Figurl' 8.
2
Tlu- typ.,s shown depend upon:
a TIll' finf' atomi:.-;ation of the liquid,
and
b C('ntrifugalforcc'.
(i
------
3
Theory is that each liquid droplet con-
tacts a volume of gas equal to the droplet
cross-sectional area are multipled by the
length of path the droplet travels
through the gas.
a By applying centrifugal force and
the liquid spray to the gas path at
the same time, maximum contact
between gas and liquid is possible.
VIII
AGITATED TANKS (Figure 9)
A Although not used extensively in air pol-
lution control, the agitated tank may
Hatisfactorily absorb gas or vapors when
solids aro also prescnt in the carrier gas.
IX
LIQUID JET SCltUBBEHS
A One type of liquid jet scrubber is shown
in Figure 10.
1
Liquid used to abBorb gases enters
apparatus through the top.
2
Vapors or gaseB are induced into the
upper side.
x
OPE BATING PItOBLE;MS
A Low temperatures of operation are necessary
for absorbers, else the equilibrium may
shift to an infavorable balance.
Thp n'quircment of temperature below
1000<: is a prime limitation to the absorp-
tion mdhod of pollution control.
a Stack gases cannot be treated without
cooling them. This destroys natural
draft and imposes a large cooling
load on th(' plant.
B Entrainment Ai,eparators must be installed
after mOf:lt aD80rbers to prevent carryover
of the absorbent and creation of a new
problem of air pollution.
C The unrecovered entrainment plus the
absorbent saturating the gas leaving the
-------
- "
_A~:JH~!:~ers
---
,!.9.!L.f!\....T~IL
eo,
~o\tr~~~
.~._II..
..r..1,~!I-
i
1M."" .~
.~'.-II!I.IL.
I!IIMI,.J11I!L.
_DIIAI.II,-
. '-~~OLD ~II -.
"'igur',' B --
I"iglll'" 7
I
I
I
.AG1T~I~D__I~J~L
_WATE R JET. SCP.HR~ER...
.LltMD '~.1:0,IO(, "310,
.W - 011
.' HO"-C:,*O(~~'IIL~S,
GAS INLET--
- !~Ii.~
-. _B~FFL~
.A..61.1:ATOR
STA8!'=!.ZER RINO
J)~~1.Ii..
-fl';;l
1"i~ul'(~ 10
I" i I: III'" ! I
7
------
--- -
-------
1\ b::; 0 r 11(' f' S
~ --_.---~----. -. ----. '-----
abso d)(' rs comprise an opt'rating los::>
Will l'I I adds to tlw make-up absorl)('nt.
D All s('('ubb('rs have' the problem of
corrosion
I';V('II wlwlI no ch('mically cOfTosiv('
"ollsllllH'lIts (}lay be' contairwd in Hw
catTi,'!' gas stre,un, th(' caf'bon dioxide
pf'('S('lIt ('olltr'ibutes to ('orrosion.
2
Wh('11 ('otTosive agents are contained in
'[h(' g;1S stf'PaID, corrosion will occur on
wd nwtalli(' surfac('s.
:;
CotTosion J'('sistallt mater'ialn, such as
s!Il','i,d alloys, rubb('f' lined Hte('I,
('a !'IIOII linings, and cf'ramic lining,..; may
hav (' lo 1)(' us p(L
II
HEFBltENCBS
1
McCabe, L. Air Pollution. Chapter 37.
McGraw-Hill Book Company. 1.952.
2
Air Pollution Abatement Manual. Chapter.
10. Manufacturing Chemists Association,
Inc. Washington, D. C,
3
Nicklin, G. T. Some Recent Developments
and Applications of Scrubbers in Indus-
trial Gas Cleaning. Proe. ~PCA, 52nd
Annual Meeting, Los Angeles.
June 21-26. 1959.
-------
Environmental
Science & Technology
A guide to scrubber selection
Edward 8. Han'
V oluIII\' I, "urnlwr:!
I'III\I'~ IIH-II:;, h'hrulln 1!17H
('UP\ ril:hl I!I7H h,\ IIII' Allwrinln Chl'mkal Sol'i('ly IInd rcprinh'd 11,\' Ill'rmisHlon..r thl' l~ol'Hil\hl (lwnl'r
-------
Edward B. Hanf
Ceilco/I' Co., Berea, Ohio 440/7
A guide to scrubber selection
A,r pollutal1b, cell,ul1ly ,I far-
I anglllg IIIdn~lri;d p",hklll, arc perhaps
hl'" l'I.",dil'd hy Ihelr phY\lcal charae-
lei "IIl'\ ,111<1 nol 11"I1:"arily hy IIldivid-
lI.d ""'Il"l' 'I hc folloWlllg 1,,1 of nwj,'r
I \'I'l"\ "I all 1'0IlIlLII'" " ,,,dnl lor
..11"l'II"'....1I1g LOlIlll)1 IlThlllqlll'~.
. N,,,;..,,, J:UM" \lIll\l.lIlees I,~e hy
dl"~"'11 ,ld"l1de 01 \nll'hlll d'OXldl'.
111.,' "," III:dlv all' 1'1111111'\1 "' a \'apor
...tolk
. 1.i'I,,;,1 t'litrailllllt'llt 1I'I'"d par.
tll'k... I () !}HCron.... and oVer in ~II~
tll'oIklt h\' \P10I\". dl ,tJ.!olll , :I!-dlalion,
"I ""hhllllg, and I'le~ed "I' III exhau~t
.111 \trl'~tln\
. Mi~t, 114111d p:llilell"; lorllled by
C()II,kn\,II,on of lIIokellk~ frolll thc
"1'''' '1.11,', 1':lrllcie \Ill' is lI,u.dly
1 (~ II]ll'IOIl"" 01 Inwl'1
. 1)",-- ",I,d ",II IlLk" u~II,dly livc
1IIIll.HI'" ;IIHI bfJ~lT. IOllnnl hy ~llnd-
III,!' (If dl"lllt~gl.lfIOIl 01 ..,,,lld...
. hlllll" \"I,d ",""l"'\ \llIalin
1/1,111 (IIH' 1111,,'11111, I(HIIH'd hv C0l1dl'II\;1
II! III ,\111.1,111:111(111, ('I \. \\ Ill.lll! tl' "I 111l'
1.lllll \.IIU)'"",
. 1':lItr;oill"" Il:Irlid,', 1'.111 il"k~ of
",,,''. '1<1"1<", du\I, III "IIlh'\, 1II.It ar,'
",II", h'd ,lIld ...>n\'l'Yl'd by :111 uir
',' "',III' t11l0111~h all l'\ha,,,t Vl'lIlII:olion
\, ,1,,'111
IIIIL'" Ih,' tvpe 01 1'0Ilu!;II" i, Ihu,
'''""dll' dl'iilll"ll, IhL' l'n/:II1\"'I le'l'oll-
\d,'" lor 1'lIvlrollnh:llt,d qll"hly laces
III,' \j1l""I<'II "Wh", \Y\"'II' 1,,11 he,'
11.1I1l1'" 'h,' 1" "hklll"" Wl't \eluhbers
,I'" Il'",,,,k. "lid :01'1' prob:ohly Ihe
\.:J\\'l'\1 10 ;1 tlllI\'l'I,,:d dn"aWcr; i( the
1,.111111.1111 I"" CI.II()'IV": ()r exi..,t., In a
L(I! 11}\!\'l' \'II\'IIOllltll:111. 111:t\\ fiher
h 1!llpln'd pJ."..(ll (11(1') ''''!l"'''''' ;tlC
111",1 ..11('11 ""Il'll 101 Yel, L'ollfll~iOIl
dIll" \,\,,1 ;lhOIlI ",l" \L1 nhlwr" and
,1"111/1 'IU', '1111, L'Ol\tll\IOIi I"" tlltdcl-
.. .l111l.lhk ")1 IWet In.ljo!" !l',I"'H" Wef
" rrlhhl'r... ,dhHllld In .1 WIth- ',Indy pI'
dl "1l'II"'. 'Ill". l'Il":h'iH"I...". ;IIHI L'l,lkt"-
I'"" 1'"11\"1'1," AI th.. ','nle 11111", I'll'
,"',1,'1\ ,Ill' h,lId 1'''',,,:.1 ," ~el"J'
.t! It .1" 411 ;UIV.IIHV'-. III ~:otro'ltln Iv
\1"1.1111 It!.th'II,d., dt'vdop"h'lIl. t'",
I" \ !.dl\ pl.l-,lll'" I IH'IPP'I' 10 dl\t'1I"'''
1\ 1111 ,d \\'\'1 \'lltthht'l d~'''I~'II'' .llId IIH'
,II J" 1111.11"". .IlId 1111\11 ,1111111' t~t 1\'111
110 111\ If"HlIIUt'ulltl ~'i""t" ~'\ ""fhnulu~~v
forced pl;~~tics in designmg for cor-
rosive environments.
Wd scrllbbcrs arc suilahle for a
wide rallge ol' corrosive applications
for whid] olher IYl'es of colleclors
III:OY re4"11e ,'xpensive modifications
or ullllsual desiglls. '1 he main advan-
lagl' of wl'l collectors arc conslallt ex-
hall,1 VOlllllll', eliminatioll 01 secondary
dllsl problems dill ing disl'osal, small
Sill', :OlId ahilily to clean hol or 1I10i,-
lure .Iadell g:O~l'S. Possible lIouhle spols
1111 wc\ 'cl'uhhcrs an.: al'pli<.:alion"
where cosily water clal'ilieation may
hc necessary hdOie disposal or reuse.
Freaing of watcr lilies is a potential
ha/.al'd, alld vapor plull1es lI1ay he
prl'sent dUllllg cold weather operal;oll.
Principles
Scrubhers C.III rell10ve 1'llh..:I' ~olll-
hk ga ,"" , nllsl" or paitielll:ole llI:oller
"' two b:"ic wolYs: By gas ah,orplion
or by IInpingl'II11'ni or mlerCl'plion,
NII..kalloll a Ihird l'ollecllon nlethml
i, ,. 1',l!cnted I)JOCl'SS "'I'd 1'01 du,1
alld fUll\(' I':orliclt'~ ill Ihl' ,uhnlleron
1.1l1g.:.
(i,1S oIhsorpllon involves Ihl' Iransll'l'
0' lIoxiou~ gas tflllli all,:xholu,t slream
11110 " IIquill phas..:. Jla,Sle Llcturs eon-
tmlllllg Ihl' ga,' ahsol'Plion pmceS\ arc
till' ,legrl'l' of soluhilily or chell1ical re-
aclivlly 01 Ihe g:os to be rl'lI1oved in
Ihe st:rubhll1g'li4uid, alltl the means
01 ohlamlllg intim,Ik eonl:oet hetween
the gas and liquid stream~, Normally
plan I wall'.. i, IISC'" 10 I'l'movc such
g;OSl" 01 IlIgh soilihilily ,IS hydrogell
11111'1 "'" 01 hydrogen chlOi IIle. III some
c;'~l'~. cau,llc or sait solutions may he
lI,ed becall'c they chemically read
with k" ,\ollible gasl'oll~ cOlltaminants,
For e,\anlple, ,odium hydroxide seruh-
hing liqllid I~ used to read with
chlonne g;lSe~ to proJuee ,odium hypo-
chlorite,
Impingt'nll'nt l'an hI' de,erih....d as in-
kln'plioll of Ihe cOlllall1inant and its
1l'lIloval ',om thl' air "Iream. Parlide~
IlIlpill!!" 0' llI1l':oel upon l:oqWls pa....~-
III!' or "Ih." Inl'dia placed in their
1',IIh 'J I... lI",l.lllllllanh 111\'11 arc
\\ ,,,I...d ,ill 01\ "h,' IIIll'k,ll ioa IHOCl'"
"lIIplo\" ,I IlIInlIl'oIie:otion oIlId c'lUling
cycle to cause water condensation on
,ubmicron particles. The partide size
huilds up to a level where parlicle, can
he removed hy impingement on the
pading.
Selection criteria
JI:osically, there afl~ five major types
01 wel scrubbers: ('rms-l1ow, counter-
eurrenl, wc\ cyclone, ventul'!. and vcr
lical air washer. I>aeking is used in
the lirst two Iypes. The~ packed
scrubhl'rs- -as well as spray towcr.;
and ballles. .--are described below, along
wilh their mo,1 dlicienl pollution con-
trol use,
J II cros.s.flow pa,:kl'd sl'rubber.i, the
air stream moves horil.ollially throllgh
a packed hed and is irrigaled hy the
scruhbing li4uid which 110ws wrtically
down Ihrough the pack mg. Cross-l1ow
design~ arc charac/cril.ed by low water
consumption and fairly high air now
capaclly al low pre,~ure drop. They
arc commonly used for removing en-
trained particles from air streains, as
well a~ for eillninaling ga'eous pollu-
tanls. Pilched heds will cfTectively re-
move mISt and spr.IY parlicles thn~e
microns alld larger hy impingement.
Particulate malter in the air slream
strikes Ihe wet packing, adheres to the
surLlce anti i~ washed away hv the
scruhhing li4Uid. The packing. -C~-
pecially for removing particulates--
must be ~ept wcl to prevent the par-
ticles from heeoming reentrained in the
gas stream.
A large anHlunl of en'raincd liquid
parlic,,", themselves may provide irriga-
tion of Ihe packed hed. In most indus-
trial applications, however, the packing
usually is irrigated hccause of the na-
ture of particulates removed, the low
nUcluating CIll1t:cutration of particles
removed, or the possihilily of reenllain-
ment if "lit washed away. For removal
of mis's ami entrained particles greater
than three microns in diameter, either
cross-now or parallel-now scrubber.;
give satisfactory colleclion efficiency
ami low operating costs.
'nlC paniliel-now design is a modi.
ficution of the cross-now design in
which a fronl washing spray is lIsed to
-------
r-- -
"
, \ .
Wet scrubber'
princjple~; , . . '
give rise', ~,
" io wide [angAf~ '.
...... , .. l'
,of dilsigns. ~;,. fi
'..r. '
" ft
. ..,... ~
, ~ '-
. ...:~ 'd'~'
,,, ,
'~'i :>~
:t" I,; "4
. ,;'1" "r~ ~ '. '.
--.- -----
~ I ~--
!,;",' , '.~,
"-A>"'~
":: f", ' ,:~,
~",.'
.;==-= ..... .....'
~
r: r £" -,1,
Spray towers
('t,
Wet cyclone scrubber
-- -------
--
:~'I~'~.{~'
. ~:
" ,
,*
~ ,.', I
. .~I
@ @
Cross-flow packed scrubber
r
1 'C.}, - /
= >~'t::J
...-. ~,
~: :--:
t~.t- ---'
-.' - --
,- ~~
,'~~ :--.
,. --------....,
Baffled spray towers
Gas inlet
. i'" "",
Gas outlet
to entrainment ~eparator
Vcmturl scrubber
Liquid entrainment
separator
Counter-current-flow
packed scrubber
~
Combination units
Shallow packed
bed
o
Vertical 81r w..her
Volume 4. N....ber 2, February 1970 1 t 1
-------
,<
j.
...
",;:i,-,ve I 1,.II;ilkl !low of holh Ihe [!'"
'!; :am ;ltH! "l"lllhhJIlI; IHplll1 'I hI'. ',y,,-
1,'I,t 1\ 1',IIllcuLllly L'ikellvc' for re.
1111 !\'llIg l"111 r.III1L'd Illpud.. WhL'll' I hl'
...lll ;1111 J" In,I"lt'd with \l)!HI dli'{ p.ll-
tl...'l" ; 111~ 11(1111 "prol\' J"IL'\Vllh "Idll!
hlld~llIp on I!'l' p,lcLIIl!~ \vhJ\.:h 1.'.Il'\"'"
\'\1 ,:"""1 v,,' pr,"',IJrc drop.) BCL".l\hL' 'ilL'
'(llIhhlll,' 1:c1'1I.1 01"\1" Ihrnlluh Ihe
p.I' I-.l'" ""'d ))(I IIH)h: 11.,111 nile I,u){ 01
P,l. !.!!1~: ,!l'pfh \..'''11 IlL' ll\L'tl. ()lien. :hl'
LI"\,' Ilow .11111 1',II,ilkl.jlow ,k\lgl1' Mc'
(.(1' tl1ll1\ d \..lll'l1 IllHll W.I,..Illllg 1-' re-
qlt 1,.\1 I()( 1).ICi-.1I1~ tkJ1lh... tll rnorv
111 ,1)111.. 10111 rhl" L"t11Ilhll).I!IOI1 I"" 1,1
1,,".::\\' 14'1 UHllrol 01,111 '-.1 1 L'.IIII'- L,ln)'
Ill. ,till I .!IHI IlqllHI !),IIIICIII;IIL'" ,Phi
II....,' !JllIiiJ'.I\ II! \H)\lll\i\ ~"I'l'\
/Ih' :"'j(h", l~lIw p,lck,:d \CllIhlWI I",
,!i,.! 11,,\,,1 III 1II1IdVL' "llhu1Icrnll dthl
,II! 1IIIIk' P,IJ!JI':It'''" III :hl' 1",lkn1cd
11(( I, 11;\11\ prpcl",\ ell''''''' 11,)\\/ p,I~"l'd
\L' (t!1!"I.'r... C,111 oh!.lllI hl~!11 colkL'IIO:1
',"~!{, :('I)LIl'" ;d p~IIIIL'!.: \I/L''', In Ihl~
"tIlIl11Il1\)[1 1,ln,t!.I.' '1'111', 111\01\1..'\ IJ1l'-
I,. ""'C'!}{ "f I he' IlIkl air, hdorc' II
c II 1IIl' "'l"I'hh.,:r, 1\) .Il'hll'\l' t:IV
1'1 'I,,'r ',tl','.I111 COIIl..lIII\HI... I hl' \111.: 1111
p,: ,V" Illrl!\I!!h ,I p,IV~ ~'\I hl d ;11111 J ,Ipld
~'I) 1,kl'..,tI;01l :llt)lIlJd t!1l dll',l P,IIIILI:....
[d ", !,I.'\-',' "111\ Pllh.':c'''''''' CIII.IIt-:l'''' Ihl-
1',1,1" k', I,' ,I ...!/I.' ....lld) d1:lllhl'Y 1',111 hI.:
It" ,()' II \'1:, I.1!\I:I~ 1'\1 jilL' p,ll'kl.'d hl'd,
\\',1;, I':~)P\' 1)('Jlllddi:":,111011 :11111 OjlL'ldl
:!,' l" Id,lll'I\-, ~1\',ld.:hl" I\)! Il~~cl,- I-
'111::'tl[\ 1',IIIILk ''';,II! hi'
nl.!! 1'1' ~(', li',l. 01 "'1\ 1111l-101\\ \\'"lIh
rlt
II' I'! 1'1: I,'
',)/1..'
lI>lkc.
r:\.'J,',1 I'
till'
,'!]I,I"\il_'I"
,'I!'I ',,'
4J 1/;
1;1 \;,
""
,,'d .HI ,I 1,,111 Id !,,,'.' "",), !,..d I:
t,,)W ,l"'lhl1Lr
':' ,",
,OIl1l1t'1'-"III-r,."t pad,,'" '''''lIh-
'!,1', \f J l ,I!H n~n\'\..''i IIpV.;1[ d in
h..,. :1"
II
f II' ,I 'tlIlIH'II' ,II ~(-il"I('I' ..'\: rl'( Imol.,!.:)"
~...'''~ '~~..
: ~"-~....,.,~ '
:y,t:~
1:~'
,;At~
- ---
dlrc'cl 01'1",,11 Ion 10 Ihe ,cruhhing
liqUid 'I n""", ,novlllg downward
Ihlollgl1 Ih,' p.lc\.,ed hed. W,lh the lI'e
of 'l1<'cdic l\\wl'J' p:lC~lIlg', Ilqll;d 'lIr-
I.lcc' Ic'gl'I1<'::lIlon 1\ ohl'"nc'd with IHI
;IKrl''''C III ene' gy eOll\lllnpllOl1, I.;quid
\lIrLu,:c 1L'~-'L'II\'r.I(lon 1'\ IIHHC crl1H.:.iI
10 thl' cil'cll'lIeV of .1 p:le~l'd eohllnl~
Ih,lIl Ihe '.IIII.,ee ;lIl'a of Ihe p,'e~ll1g
,"ed In 111<' ,'ollll11n
'rhl' g.!"" \1 fL'alJ\ Ilch in COII!;lllli-
11.111" ,'0111<." 11110 l'()I1I:1ci With 'penl
1I11110r "1111, h\\llolll of Ihl' p"e~c'd hed,
hnh 1111"ld ,."lIlIlg III .11 Ilk' 1\\1' of Ihc'
,,'II,hl>e, " III c'PIII,ICI wllh IIll' k.1\1
L'On!alllll1.dl'll f;I\, Thl'\ I'h.lr;tclc('J\IH-
provldl" ,,,,ily cOI1,I.IIII forc'.'
Ihr<1\,ghOiIi rhl' I'"e~l'd bl'd for drivll1g
Ihe '!.1\,'OLl" l'olt1.1I11in;lIll ;1110 the
\l'J'lIhblllg 1111'11'1. '/ hc'rc' :II,,> 1\ k"
el1,lIll'c' 111;11 ,he dl",olved g:l"" will
he ,Inplk'd \\11: of I Ill' 111111111.
A IIHlddIC:lIIOIl 01 Ihe eOllnkr.cl\r.
fellt lk"'I_~'n I... Ihe C()!II._lIJ'fL'IlI p,lckctl
'''IIlb!lC'I. I kl,', Ih,' 1-"1\ "l1d liq"id
:-,lrC;II\1' l11n,l' III the ~;tIl}C dlfL'ctinn---
11\11,1111 .1\\\\'11 Ihroll!!" Ihe p:lc~ed
hl'd. T"c,c' ,,'rllhhcr, can he opn.lled
:II hl!-,h 1-'.1' r,II,'" .1I1d, in 111<' l':I'" "f
!~'I\ ;'''''III,j,on. :It 11Igh liqllld ",k"
TIll'Y \""11., 1,'I11\\\'e :.!.I\l" of 11Igh
'.V.d'.1 ,plll"I,ly .11101 ,,,".dly :llc' d.
!ILI\.."}! I.'II():I"11 r')1 14'1110\.11 l)! k\\ "011&
hJ~ '",1\1. \
'[ hi,
11,.:11 "
In
;tllHlnl
1\\'1':11
\j':tCl'.." '.1 !',',
II li,I!H!k.. 111~'h :',1\ \'1.'1"\..'1
, J;,"" ; , [ 11 ~
,111\,'1\ [0\\1 ~r,\...... "'L'...-lhll1,d
,:-1..1', Ld' h 1II,II/I.'l! f'l~h ~';I\ \l'Il),:1
,II'" II' fl,,' \.:"I~'II\ ,10 not L';III"'L J1()(\I!
11.1'- ,1\ iI! \nltld ~II '-""hl/lllT-Cllfll'nt
11""'1.'11 h .111"l' till' !!', ....lfl':II" help\
11) 1'II\h II,,' iH(llill \~rl',lfn ttlroll!-!h Ihl'
ral'~ in~'
.--~,
....-J,.
- - - --
(rll\s.llow and counter-cllnent
"""lIhhers appear to perform Ihc same
fundion, but where highly soluble
gases 01 m,," are 10 he removed, thc
cross-Ilow pac~ed 'enlbher has several
;itlvantages, The hendits are derived
fro1l1 the eaSe wilh which ga' and
w;lter ,Iream, pa" through the cross-
Ilow de,ign, compared to the resis.
tance of Ihe opposing ,tream, in coun-
ter-elln,'lIt Ilow, U\lng the same gas
and liquid m;!,.' Ilow raks, a eross-
Ilow ,embh"" h;I.' low"" 101:lllit,Jllld rak
:llId plc'''''re drop Ik'ilks leduelng
water eOIl'lImplion drastieally. the
cro".llow principk al,o red"ce, pump
and f;,n mol or sil.es, Olher :ldV:lnla[!eS
Illelude kss plllg[!ing 1'1'0111 ,olids
dropout at the packing support plate
and the possihk '''e of higher [!;IS and
liquid r;IIes becall,e of the exlremdy
low pressure drop,
The economical brcak-even point
hdweell the two s""ubher designs is
ha,ed 011 the p"e~ing depth required,
If packing re'luirem-:nts fer eross-
!low l'Xceed six kd, Ihe counter-cur-
relit Ilow de,ign usually has .1 Iqwa
"p"""I;ollal cost. A, pre\iollsly noted.
cro".llow and coullkr-current .,nuh-
bc" 'lSe p;'l'kings, Traditionally, cc-
r.lInie packings have heen C wid"" "'.e, Pla,tic packillgs have
tlte adv'"II;q;e <,I' heing virtllally un-
I\I':;I~,lhk. '"1<1 Iheir lighter we;ghl also
pen;lIl, ,,".dkr w'oIl SCI "hhas. 1'1'0-
vldill~: equqlllll'nl (;(1\' ,avings, One
e\ample III the IIc'Wcl pl.IYl'lhykne
i\,\c~ill[!., !tradc'm,,, kl'll I dkrelld, ha,
Ihe ,h.\pe of a hel;, that is formecl
IIltO ,( dOllghnll1 (loroid) shapl'. In
"dd'IIOIl to .1 low pressure drop, it has
-------
"':-
Comparison o' scrubber operating cosb
Scrubber Total Annual
liquid Liquid pressure pressure
rate pressure drop drop power
Scrubber type (g.p.m.) (p.5.i.g.) Pump h.p. (In. water) (in. water) Fan h.p. Total h.p. cost
Cross flow
Tellerette packing 50 5 0.3 0.5 1.5 4.3 4.6 $ 370
Berl saddle packing 60 5 0.4 1.2 2.2 6.3 6.7 540
Raschig ring packing 60 5 0.4 3.8 4.8 13.8 14.2 1140
Counter-current
Tellerette packing 120 5 0.7 0.75 1. 75 5.0 5.7 460
Berl saddle packing 140 5 0.8 2.2' 3.2 9.1 10.0 810
Raschig ring packing 140 5 0.8 6.7 7.7 22.0 22.8 1840
Wet cyclone 80 60 5.6 3.5 4.5 12.8 18.4 1490
Spray tower 100 80 9.6 2.0 3.0 8.6 18.2 1470
Jet 600 60 42.0 1.0 none 42.0 3380
Venturi 80 20 1.9 15.0 16.0 46.0 47.9 3860
,I supenor ab,ltty to provide liquid
sillfac,' Il'generutlon.
Absorpllon IS relallvl'ly rapid when
g." lirsl eOllll'S info cOlltact with a
1"1"111 Alft'r Ih,' surlace of Ihe liquid
b.'l'Ollll'S saturated, however, the llis.
solved gols 111lIst Jitfuse from Ihe sur-
Lice.. slow process. Turbulence will
brtng I n"h liquid 1o the surface anJ
h;"ten Ihe absorption, but this requirl':;
,ldJll,onal energy ami higher operat.
Ing co~h.
rellc-"'Ile packing was Jesigned with
I I.II!:" IIIIIlIber of IIIterslilial holdup
p"inls al wlm:h the liquid comes 10-
gell,,', ,lIId ,lisl'erses ;'galll, exposlllg
",'W SIll face lor ahsOI pilon wilhout
,., Idllll~ "11,'1 gy to the sysknl. This
111. ,U". Ihal Ihe Itqu;d surface is con-
,'.IIIII\' "Ii"nglllg and" relwwl'd as the
1"1"111 1""g"',,es througlt lite p;lI.:ked
I.,."
Wd ndlltH' scruhbers arc efficient
f,,, "'III
-------
c.LII1.). and ,ts low pressure drop
(which usually is less than 1.0 iDches
of waler). The low presure drop re-
sull~ in extremely low operating costs,
bcc~use of the savings in required fan
horsepower. However, this washer de-
sign should not be used where a rela-
tively high concentration of gaseous
contaminants is prcsent in the air
stream.
Spray chambers utili7-c the principles
of interception--<:ontact between the
mist particle and spray droplet. They
ale an economical solution for remov-
mg large liquid particles from air
sln:ams where emciencies bclow 90%
.are salislaclory.
RaBIe spray towers require a high
gas velocity. with a resullant high
pressun' drop to force particles against
the bames which arc welled continually
with spray droplets. Well designed
spray towers give collection el1kiencies
to 90% on entrained liquid particles
greater than 10 microns. They arc ex-
pen~ive 10 operate because of high
pre~sure. high volume, ami high fan
operating n'quircments.
SI:veral Iypes of scruhbers arc some-
times in series. A wl'l cyclone/ con-
current p;u:ked scrubber combination,
for example. removes highly soluble
nox.lous gas and dust present in the
same gas slream. This combination
consisls of two sections built essen-
tially inlo one housing or shell. The
lop sect Ion is a wet cyclonc design'
which removes the dust particles by
ccnlrifugal force. The dust is washed
down the shdl of the scrubber into a
lallnder placed above the packed bed.
After passing through the cyclone sec-
tion. Ihe gas stream cnters a packed
bed where the highly soluble gas 18
absorbed in the irrigating liquid. This
particular design permits a high face
Vl'locity 111 both the cyclone section
and concurrent packed section. This
red\ll:es the span' requirements for the
1I1;lIn sl'luhber shell. but u separate
l'ntrai,""ent sepurator mllst be pro-
vided when this combination is used.
The wet cyclone docs provide some
initial gas absorption while removing a
lurge percentage of the solid particu-
lates. The concurrent seclion removes
the majority of the remaining soluble
gases and most of the remaining solid
particulates down to five microns.
The disadvantages of this approach
(wet cyclone! concurrent combina-
tion) arc that the height requirements
arc excessive and may not be available.
A top inlet! bollom outlet arrangement
may not suit the total system require-
114 Enyirnnm~,,181 S<:ience iii Tedtnolo8y
Industrl.1 wet scrubber .ppllc.tlons
Steel Gases-HCI
Liquid entrainment-H2S04
Gases-HF. NO"
Liquid entrainment-NaOH,
HNOa. H.P04, cyanides
Mists-H,Cr04
Dusts-AIF., AI,O.
Gases-HF
Fumes-AICI.
Gases-{;I,. CIO" CS02
Liquid entrainment~H.OH,
(CH.)2CHOH, amines DSMO
monochlorobenzene
Gases-H,S. CSt
Liquid entrainment-H.P04,
acetic and maleic acids
Metal finishing
Aluminum
Pulp & paper
Pha rmaceuticals
Food processing
Textiles
ments. An entrainment separator must
be supplied.
Another typical combination is a
wet cyclone followed by a cross-flow
packed scrubber. Similar to the con-
current combination. this combination
will handle dusts above five microns at
high loadings, and highly soluble gases.
The wet cyclone! cross-flow com-
bination provides economical reeovery
of gases from an air stream loaded
with solid particulates. Again, the wet
cyclone acts n.~ a pretreatment or
initial scrubbing section while the
.cross-flow acts as the tail gas scrubber.
The heaviest portion of the solids is
knocked out in the wet cyclone. The
gases and smaller particulates arc re-
moved in the tail gas packed scrubber.
Elimination of the solid particulates
before the glilies enter the packed
scrubber lessens the possibility of blind.
ing the packing support plate or build.
ing up heavy solid depositions in the
packed bcd.
The advantages of a wet cyclone!
cross-flow combinntion over the wet
cyclone! concurrent flow are:
. Greater flexibility in choice of
scrubbing liquors for each section.
- Recovery in either stage without
contamination from previous stage.
. More efficient gas absorption with
greater overall efficiency.
. Separate housing permits separate
installation, allowing for spreading of
initial investment over a greater time
period.
Gases-H,S. CSt. HCI
Liquid entrainment-H,S04
. A flexibility that permits addition
of more packing at later date for in-
creased gas absorption.
. The crO!ls-fIow scrubber acts as a
built-in entrainment separator.
Other combinations, such as ven-
turi's followed by croSs-flow scrubbers.
concurrent followed by counter-cur-
rent, venturi followed by counter-cur.
rent. etc., can be adapted to handle a
specific requirement. The exact com-
bination best suited for the problem
would be based on performance re-
quirements, nature of contaminants.
and costs (initial and operating).
."nfarced pIntIc
Construction materials availablo for
scrubbers used in corrosive service
include glass fiber reinforced plastic,
lined steel, stainless steel, and costly
titanium and nickel alloys. Reinforced
plastic, for a number of reasons, is
probably bettcr luited to more cor.
rosive services than any other ma.
terial. Three major criteria-resistance
to temperature, corrosion. and abra-
sion--decide what PltP scrubbers can
handlc.
. Temperature .laaltatloa of FRP is
usually in the ranae of 2S0o F.-300" F.
Quench chambers located before FltP
wet scrubbers, however, frequently can
solve a high temperature problem,
. CorrosI.eI gencrally are not a
problem; polyestcr, epoxy, or furan
resin systems handle most corrosive
materials. The exceptions are a few
-------
concentrated oxidizing agents, such
as sulfuric acid above 70% concen-
tratIOns. Reinforced polyester offers
the broadest range of corrosion pro-
tection; furans usually arc used where
solvents or organics are present in
4u,lntlty; and epoxies have the best
alLlii n:sistancc.
. Abru\ion resislJlncc usually docs
1101 prcsent a proolcm with FRP wet
scrllhoers. occaus,' "ddlng air and
w,lln III thc cOlltrol process reduces
the' ,dH"'d\l' aCII"11 01 the solids.
(icn,'r.II'I', 111111,,1 l'll'lipment costs
pi 'kP '1I1I1s ;(1'(' ~1\ low :1\ Ihn.'e
'I" III,. Is ,",, Clhl ,,/ IlioOcr.I,,,,'d sted,
"11,' tlllrd II,,' ,'"'' "f cnamic, and one
l1,dl ,11,' cl"l ld ,'eld onek.llned e4ulp.
1)1\'0\1. ,llId milL'l, f,'" than ul1ih of
,1.1",k" sled ,lIld 1I\lIIC l''OtIC "lIoys
()II I,Lrg,' c\.ju'l'lIlcnl, ICIIII.Hccd 1'1"'11<':
Il1d~ hc cornl'dllJ\,. Wllh Sllch corn
""'11 11",I,'rl,d, ,IS ca' h011 stcel hecJIISc
!l1l' c",t of halldllng ,,"d fidd.wellhng
I.lrg" ,I'l'l c4111prncnl " hl/!h. Installa.
11011 cOst /!I'IIL'rally IS low, due to
fighter wl'lgIIl, Ie" "'I'POI"Is, tlexlhillty
0f l"c"IIOIl. Il'dllc,'d shll'l'lng cost, and
,,"s' lidd t.,hl"il",tlll'n IC'lulpment flc'
'I"l'nllv IS shlPI'L'd ,I",'mhkd),
."1.IIIIkn,IIILT 01 ,I
-------
ABSORPTION
EQUIPMENT:
I INTRODUCTION: LIMITATION OF APPLICATIONS
Absorption of gases is one of the oldest and
most common methods of preventing the discharge
of gas and vapor pollutants into the atmosphere.
Various means to achieve maximum absorption
are designed into such control equipment, but
most types are either packed, grid or plate
towers, spray towers or chambers, or wet type
inertial scrubbers. While this equipment is
similar to those in the process industries,
absorbing systems employed in air pollution
control have certain limitations.
A
Excessive Temperature
Pollutant gases, especially [rom combustion
processes, are emitted at elevated tempera-
tures, requiring cooling before gas ab-
sorption becomes practical.
R
L~rge Volumes, Small Amounts of Pollutants
CdS volumes LIre often very large in com-
parison to the amount of pollutant to be
removed, therefore costly to move and cool.
C
Choice of Absorbing Liquid
Water
2
If water is used in great quantities,
this may be expensive; if waste water
is used, it may transform an air pollu-
tion rroblem into a water pollution
problem. Slqdge and liquid wastes are
often real disposal problems.
Liquids Other Than Water
D
Other absorbing liquids usually require
stripping for reuse, an additional cost.
Also provisions often have to be made
to prevent absorbing solution spray
carryover.
Economic Recovery Considerations
Most processes vent to the atmosphere only
gases which are beyond the point of econo-
mic recovery. Unless the reaidual gases
received can be turned into u saleable
or usable product, most industrics consider
further scrubbing an added cost to their
product and do so only because legal or
public opinion requires them to control
their vent gases.
E
Loss of Effluent Buoyancy
PA.C.ge.12a.12.70
SELECTED
APPLICA TIONS
Liquid scrubbed gases exit at lower tempera-
tures and with a higher water vapor content.
This is a disadvantage for good meteorolog-
ical dispersion of the effluent.
These problems then make most gas absorption
control methods rather specific to meet the
circumstances of the application, such that
the same pollutant may be economically
scrubbed from the atmospheric discharge of
one industrial process and not from some
other.
II
APPLICATIONS
Briefly described below are several applica-
tions of absorption methods employed (or
proposed upon the basis of laboratory and pilot
plant studies) for the reduction of gaseous
pollutants.
A
Sulfur Dioxide in Flue Gas
Emission of sulfur dioxide has become an
increasing problem in the very large coal
burning steam boiler plants. For economic
reasons, coal of relatively high sulfur
content is being used. No method, absorp-
tion or any other, is presently completely
satisfactory for use with large steam
boiler plants, but several wet scrubber
methods have been devloped and have shown
promise. Three such methods are considered
here:
1
Limestone or Dolomite Injection with Wet
Scrubbing
Sulfur oxides produced by burning coal
or oil can be reacted with the calcined
products of limestone of dolomite to
form removable calcium - sulfur salts.
Iron oxide, which is present in most
dolomites, acts as a catalyst by speed-
ing the reac tion of CaD and Mgo and 502
to CaS04 and MgS04. The injection pro-
cess can take two forms: (1) Dry removal
of SOx by injection of powdered limestone
or dolomite into the gas steam, or (2)
wet remova] by following the dry inject-
ion by wet scrubbing.
The wet absorption process was developed
by Combustion Engineering in cooperation
with the Detroit Edison Company. There
are two commercial installations using
this process at present and a third 1s
1
-------
Absorption Equipment:
Selected Applications
slated Lo be operational by 1971. In this
process the pulverized additive is in-
jected into the furnace where 20 to 30%
of the SOx is removed. The remaining 502
and calcined additives then pass through
<\ preheater and into a wet scrubber. The
l'alcined additives react with wash water
in the scrubber to form hydroxides. These
hydroxides react with the 502 and any
unreacteu 50) to form slightly soluble
sulfite~ and sulfates. These salts, along
wi th the fly ash which is 99% removed by
the scrubber, are sent to a clarifier and
to disposal. A flow diagram is seen in
Figure 1.
r---l
I I
I I
I COAL I
I SUPPLY I
I I
I I
L- -.J
LIMESTONE
SUPPLY
MILL
FURNACE
2
Wellman-Lord Process
A wet absorption method using potassium
or sodium sulfite scrubbing solution has
been developed by Wellman-Lord, Inc., a
subsidiary of Bechtel Corporation. A
pilot plant unit has been operated at
the Gannon station of Tampa Electric
Company. A demonstration unit at the
Crane station of Baltimore Gas and
Electric was operated until September
1969. The process has been licensed to
two Japanese firms for Asian sales and
promotion. The first full-scale commerical
application will be for the Olin Corp.
10 STACK
. FIGU~E 1. WET COMBUSTION
1_- ------------------------------------- -
Although, 98% removal of S02 is pos!>ibJe
under iueal condItions, 60-75% removal
has l",en reported for thp commer ical
Installations (using less than stoichio-
metric additIve) along with 99% removal
LJf fly ash and 100% elimination of SO).
l~crc are also indications that thiH
process can remove 20 to 30% of the
nitrogen oxide emissions.
SCRUBBER
~E
AND
MAKE-UP
WATeR
SETTLING
TANK
TO DISPOSAL
ENGINEERING
at a 700 ton per day sulfuric acid plant
scheduled for completion late in 1970.
The original design called for a potassium
sulfite scrubbing solution. The absorbed
502 fanned potassium bisulfite which on
cooling precipitated oUt as potassium
pyrosulfite. Steam stripping the pyro-
sulfite produced anhydrous 802 for re-
-------
covery and regenerated potassium sulfite
for recycle. Pilot plant work at the
Gannon and Crane stations indicated
high energy requirements for the potassium
solution system. Parallel work was done
on " sodium solution system to reduce
utility requirements and capital costs.
This sodium system will be used in
Wellman-Lord'« first commercial instal-
lation for Olin. Detailed technical
information for the process lias not been
released and only the most general type
of flow diagram is available (See figure
:2). Wl'lJman-Lord has predicted performance
figures [or their process u>Jing the
sodium system. Better than 90% 802 re-
moval, 97% SO) removal, and 90% fly ash
removal (with" loading of 0.5 grains per
cubic foot) are claimed.
-~~-------------------- --------
SODIUM SYSTEM
10 STACK
FLUE
H20
Absorption Equipment:
Selected Applications
passes on to the reducer. At 1100°F in
the reducer the sulfates and sulfites in
the solution react with producer gas
(CO and H2) to form a sulfide solution
which is sent to the regenerator. In the
regenerator at 800°F the sulfide solution
is reacted with C02 and water (from the
reducer) yielding a regenerated molten
carbonate mixture to the absorber and
a H2S stream to a Claus unit. A flow
diagram i8 seen in Figure 3.
Although only bench Beale work has been
completed, 99% removal of 502 in gas
streams containing 0.3 to 3% 502 has
been reported. There are also indications
that the molten salt technique can control
nitrogen oxides.
SULFURIC
I .bCID PLANT
I
I
I
I liQUEFACTION
PlANT
I
I
Y SULFUR
RWf>N
FLY ASH, 503
- ABSORBER AREA- - - - - - - - -.- - _.- - -CHEMICAL AREA--
- ------- --------
---~-------"'---_._--- ----
FIGURE 2 WellMAN - LORD PROCESS
Molten Carbonate Process
/\ process for scrubbing hot flue gases
with a mixture of molte~ salts has been
developed by Atomics International, a
division of North American Rockwell Corp.
In this process, the flue gas passes
first through a high temperature electro-
static precipitator and iy then contacted
In Nn absorber with an eutectic mIxture
of lithjum, sodium, and potassium carbon-
ate at nbout 800°F. The resulting solution
of carbonates, sulfates, and aulfltes
B
Sulfur Dioxide in Smelter Gases
Sulfur dioxide is a waste gas product in
the smelting of many metal sulfide ores.
Many years ago, these waste gases were
emitted to the atmosphere, but today,
both to prevent air pollution, and for
economic reasons sulfur dioxide is re-
covered from smelter waste gases. It
should be noted the sulfur dioxide content
of smelter gases is much higher than for
flue gases. The recovered sulfur ends up
as liquid sulfur dioxide, sulfate fertilizer,
3
-------
Absorption Equipment:
Selected Applications
10 STACK
HOT FlUE ElECTROSTATIC
PRECIPITATOR
800 + of
CARBONATES
SULFATES
SUlFITES
GASES
RECOVERED H S
2
C02,WATER
MOLTEN CAR
& SULFIDES
~~r
JES
PRODUCER
GAS Co, H2
FLY ASH
TO WASTE
---
FIGURE 3 NOLTEN CARBONATE PROCESS
nr sulfuric acid. Two basic methods used
in this country are:
1
ASARca Reduction Process
The American Smelting and Refining Co.
(ABARCQ) first used a similar but now
obsolete process in the early 1940's
on a semi-commercial scale. Although
this process does not involve gas ab-
sorption, it is included in order to
be complete. The new ASARCO process
uses sufficient natural gas both to
react with all the oxygen in the waste
gas and to reduce sulfur oxides to sulfur.
The hot off gas is first water-cooled
and ~len cleaned by an electrostatic
precipitator. After heat exchange,
the off gas is mixed with natural
gas and sent to a temperature controlled
combustion chamber. In this furnace the
sulfur dioxide i8 reduced to sulfur,
and carbonyl sulfide (COS) and hydrogen
sulfide (H2S) are formed by side reactions.
The gases are further cooled and then
enter a hauxite catalyzed reactor where
the carbonyl sulfide is converted to
sulfur. The sulfur in this stream is
thl'n colll'cted in the liquid form by
an electrostatic precipitator and sent
,1
to, storage. The gas stream is then heated
and passed through two catalytic reactors
which convert the remaining hydrogen
sulfide to liquid sulfur. This sulfur
is also sent to storage. See Fig. 4.
2
Economically the optimum range of .off
gas concentrations is from 5% 502 and
12% 02 to 7% S02 and 9% 02' Sulfur re-
covery is reporfed to be 95% of the
total sulfur in the off gas.
Ammonia-sulfuric acid process
This process, sometimes known as the
ammonium sulfite-bisulfite system was
pioneered at Trail, British Columbia,
years ago, as a means to recover sulfur
dioxide and prevent air pollution. In
brief, an aqueous solution of an ammon-
ium sulfite and bisulfite is recirculated
through a scrubbing system. Continuous
portions of the scrubbing liquid are
drawn off, and also anhydrous ammonia
is continuously added to the scrubbing
liquid. A proper balance of addition
and bleeding for optimum scrubbing con-
trol is determined by continuous pH
control. A portion of scrubbing liquid
removed from the system is treated with
sulfuric acid, forming ammonium sulfate
-------
Hot
Off gas COOLER
U1
~o:::
~O
1-'1-
1/,..(
O!=
O:::Q..
I- -
UU
WW
......0:::
wQ..
liquid sulfur
to storage
Water
Steam
HEAT EXCHANGER
Stea
~o:::
~O
I-'~
(/).....
0-
0:::Q..
.....-
uU
WW
......0:::
wQ..
2200°F
FURNACE
Natural gas
U
- 0:::
!;(O
t;~
ot::
0:::Q..
""'u
Uw
Wo:::
U:;Q..
To
Stack
~O:::
~Q
(/)~
0-
o:::~
.....u
Uw
u.I 0:::
U:;Q..
Steam
FIGURE 4. ASARCO REDUCTION PROCESS
-------
Absorption Equipment:
Selected Applications
and evolving sulfur dioxide gas. One mole
of sulfuric acid produces between one
and two moles of sulfur dioxide gas,
the exact amount varying with the ratio
of ammonium sulfite to ammonium bisulfite
in the scrubbing liquid removed from the
scrubber. The pure sulfur dioxide obtained
is dried with sulfuric acid. The ammon-
ium sulfate obtained is stripped with
steam in order to eliminate any residual
50 in the ammonium sulfate solution
wh~ch is crystallized, centrifuged and
finally dried as a marketable product.
See Figure 5.
---------------~----'
WATER
WEAK
H2~
Falk describes the control of sulfuric
acid fumes emitted in the manufacture of
a paint pigment. Many industrial sources
of sulfur acid mist and gases are emitted
continuously, but in the batch production
of titanium oxide, the emission of sulfuric
acid is very intense for a relatively short
time and very small the rest of the time
during production. Ilmenite ore, an iron
titanium oxide, is added with sulfuric
acid to the reaction vessel vented to the
atmosphere. To initiate the acid-ore re-
action, oleum or dilution water is added,
either of which produces heat. After "set-
TO (N~)2~
RECOVERY
- -----.---------.-------
FIGURE 5. AMMONIA- SULFURIC ACID PROCESS
More recently, this method has been
developed by the Olin-Mathieson Chemical
Corporation to control air pollution and
recover sulfur dioxide in tail gases
emitted in the manufacture of sulfuric
acid. This latter process reduces tail
gas content as high as .9% sulfur dioxide
to a value as low as .03 of 1% in a two
stage scrubbing process.
C
Acid Fumes in a Pigment Manufacture (DuPont)
()
off" as this addition is called, the re-
action proceeds slowly, until suddenly a
tremendous amount of steam and pollution
("attack gas") are emitted reaching a peak
of the order of 120,000 cfm; io a few
minutes the mist and gas release again
return to a low level.
Abatement measures in this process require
equipment capable of handling sudden peak
loads of sulfur dioxide, sulfur trioxide,
-------
clnd sulfuric acid droplets along with much
steam and son~ meta] ore dust in a manner
easily adJpt~d to batch processing. If a
w~t control process is to be used, it
should not be too costly or creatp a water
p\lllution problem.
Declded upon at this plant (DuPont) was the
IIse \If a 72" steel plate rubber lined jet
,",crubtH'r system (Schutte-Koertlng) employ-
"Ing " primary and a circulating secondary
Jet scrubher system. To reduce equipment
corrosion, the pll of the scrubbing system
is controlled with the addition of lime
slurry to ;) collecting-holding tank. A 1000
gal. per minute, 100 HP pump continuously
supplies water to the 3" primary jet through-
out the attac-k cycle. Surrounding the primary
jet are 72 secondary jets, each 3/4" in
diameter, supplied by an 8000 gpm 300 HP
pump. Both jets discharge downward into a
15,000 gal. tank. The stack that vents the
reaction vessels is connected to the scrub-
ber through a tee and damper arrangement.
The system depends primarily on condensation
of steam through the jet, thus creating a
vacuum tu draw the fumes out of the reaction
vessel stack. The holding tank is emptied
once a day or more frequently if necessary
in order to kt'ep the scrubbing solution cold
and to rrti'vent huild-up of the lime salts
that w\luld clog the system.
[)
Hydrogen Sulfi,lL> 1n Rpl inery "ases (GirbotoJ.)
~:
Sui fur ImpurJ ti.es i.n natura 1 gas and pet-
roleum appear as hydrogen Hulfide and
Inf'rcapLll1s. In some refinery off gases,
hYdrogen sulfide was burned in flares, but
the trend today is to recover the sulfur
as a valuable by-product. A regenerative
system for the recovery of hydrogen sulfide
is the Girbotol process. By this process,
the gas to be scrubbed passes counter- cur-
rent in a plate tower to an absorbing solu-
tion of either monoethanolamine or die-
thanolamine. This absorbent solution is
regenerated in a second plate tower or
reactivator (stripper) where the hydrogen
sulfide is stripped with steam.
Chlorine - Carbon Tetrachloride Process
(niamond Alkali)
Chlorine gas is a part of many chemical
1'"p[lrt!ons in the chemical industry not
;111 (I f wit 1 ch Ilre cloHcd systems. When
thiH gas if'! vented to the atmosphere,
t'ven 111 small amounts, it is a potential
ai r pollution problem unless means
an' takf'1I to remove the chlorine from vent
gas.
Absorption Equipment: Selected Applications
There are various scrubbing methods to
prevent the emission of chlorine in vent
gases, but the method developed by Diamond
Alkali Company is somewhat unusual. It is
based upon the differential absorption
of chlorine in carbon tetrachloride in
a pressurized packed tower, followed by
recoverey of the chlorine in a pressurized
stripping tower.
Figure 6 shows a typical recovery unit where
a chlorine-air mixture is pressurized to
100 psi and at this pressure cooled succes-
sively in a water cooled and refrigerant
cooled heat exchanger. The cooled gas at
apprQximately SOF enters the bottom of
a packed column where it is scrubbed counter-
current with carbon tetrachloride entering
the top at OaF.
VENT GAS
CONDENSER
LIQUID
CL2
FIGURE 6. RECOVERY OF CHLORINE OR "SNIFT GAS"
The absorbing carbon tetrachloride enters
the stripping tower half-way up where chlorine
is stripped in the lower half with a siphon
reboiler used at the bottom to provide
the heat necessary for stripping.
The chlorine free carbon tetrachloride
leaves the bottom of the stripping tower
at 260°F, is cooled to OaF and returns to
the top of the packed tower absorber. The
upper section of the stripping tower is the
rectifying section; here rising chlorine
vapo; in contact with the refluxing liquid
chlorine and the resultant pure chlorine
gas, free of carbon tetrachloride, exits
from the top of the stripping tower. The
chlorin~ can be recovered as a gas or con-
densed and recovered a8 a liquid according
to the needs of plant operations.
F
Laboratory Hood Exhaust:
Application (ANL)
Spray Tower
7
-------
Ab~orption Equipment:
Selected Applications
An interestlng application of a horizontal
spray tower for the removal of halogens,
carbon djoxide and aerosols in laboratory
air is described by Liimatainen and Mecham
of the Argonne National Laboratory. The
system was designed for removal of highly
reactive and toxic halogen compounds such
ns hrom 111(' pentafluor1 de, bromine tri-
fluoride, etc., but was found also very
pff0ctiv0 for removing carbon dioxide. A
spray t.ower with its relatively low pres-
Hurl' drop was chosen instead of a packed or
plate tower, sInce low pressure blowers
and light duct work moved air through the
system at 6000 cfm.
The scrubber, 4 ft. x 17 ft. of welded
1/8" steel plate consisted of three succes-
sive sections, each having a group of four
hollow cone spray nozzles (Schutte-Koerting
662C) directed toward cast iron throat
pieces mounted upon the scrubber dividers.
The tower was horizontal, with gas and
spray liquid moving co-currently. A stag-
gered array of baffles followed by a 4"
filter of monel fibers to remove entrained
droplets was located inside the tower (or
chamber) at the exit end. Finned tube steam
heaters were used to prevent condensatiori
and give buoyancy to the effluent.
The scrubbing solution was between 6 and
10% by weight of potassium hydroxide and
was recirculated through the scrubber and
a recycle holding tank with a black iron
7.5 HP centrifugal pump. Piping to the spray
headers was 3" blackiron. Liquid flow was
of the order of 100 gal. per minute.
For a range of inlet concentrations up to
700 ppm of bromides, fluorides and iodine,
efficiencies of absorption range from 70
to 100% with the least efficiency applying
to the bromides. Aerosol removal efficiency
measured at 0.5 and 0.1 microns ranged
between 35 and 57%.
(;
Oxides of Nitrogen
(DuPont)
Ammoniacal Process
NiLr(1gen dioxidc is one pollutant which
reveals itself as a characteristic reddish
brown plume when emission concentrations
urp 50 ppm or greater. Waate oxides of
niLrogen are vented to the atmosphere in
several indus trail processes, e.g., the
manufacture (If njtrlc acid and the manu-
facture of sulfuric acid by the chamber
prOl'l'AH. One company, DuPont of Canada,
recognized this potential air pollution
at their nylon intermediate plant at
8
Maitland, Ontario, and so applied controls
on tail gases of the nitric acid plant
and also on off gases from other processes.
The first step in their control of oxides of
nitrogen was to collect all vented gases
and deliver them to an absorber where waste
liquor containing dilute ammonia and caustic
scrubbed the gases in a packed tower. See
Figure 7. This system controlled oxides
of nitrogen, but created another air pollu-
tion problem in the form of a heavy white
plume which contained finely dispersed
ammonium salt particles. This secondary
air pollution problem was solved by a
venturi scrubber and mist collector.
TO ATMOSPHERE
NO
GASES
;
VENTURI
SCRUBBER
TO DRAIN
WASTE
LIQUOR
FIGURE 7.
NITROGEN OXIDES ABATEMENT PROCESS
The absorber was constructed of rubber lined
mild steel. Duct works and other equipment
coming in contact with the waste gases were
constructed of 304 type stainless. Piping
handling the alkali scrubbing solution was of
mild steel. The scrubbing liquor averaged
around one half of 1% sodium hydroxide and
sodium carbonate with generally slightly
smaller amounts of ammonia. This scrubbing
liquor was recirculated until exhausted,
then it was dumped. It was found that the
degree of exhaustion could be measured by
pH. This presented an easy method of control
using a recording pH meter and an alarm.
The venturi scrubber and separator were de-
signed for a gas flow of 700 cfm and a
liquid flow of 42 gpm with a total pressure
drop of up to 22" water gauge. Recovery
efficiency was 99%.
-------
REFERENCES
Maurin, P.G. and Jonakin, J., "Removing
Sulfur Oxides from Stacks," Chern.
~., 11 (9): 173-180, (l97~
2
Martin, J.R., Taylor, W.C., and Plumley
A.L., "The C-E Air Pollution Control
System," Paper presented at 1970
Industrial Coal Conference, Lexington,
Kentucky, April 8-9, 1970.
3
Craig, T.L., "Recovery of S02 from Stack
Gases--The Wellman-Lord S02 Recovery
System, "Paper Presented at 1970
Industrial Coal Conference, Lexington,
Kentucky, April 8-9, 1970.
4
Oldenkamp, R.D., and Margolin, E.E.,
"The Molten Carbonate Process for
Sulfur Oxide Emissions, "Chern. ~.
Progress, 65 (11): 7}-76, (1969).
')
Argenbright, L.P. and Preble, B., "S02
from Smelters: Three Processes Form
an Overview of Recovery Costs,"
Environmental Science and Technology,
!!.. (7): ';54-561, (1970).
6
"Cost Estimates of Liquid Scrubbing Pro-
cesses for Removing Sulfur Dioxide
from Flue Gases," U.S. Bureau of
Mines Report of Investigation No.5469,
1959.
Absorption Equipment:
Selected Applications
7
Mallette, F.S., (Ed.), Problems and
Control of Air Pollution, Reinhold
Pub. Corp., N.Y., 1955.
8
Kohl, A. F., and Riesenfeld, F. C., "Gas
Purification," Chem. Eng., 66 (12),
1959.
9
Falk, L.L., "Reduction of Sulfuric Acid
Fumes," AlHA Quart., 11 (4), 1951.
10
Sutter, R.C., "Recovery of Chlorine
from Air-Chlorine Mixtures," JAPCA,
1 (1), 1957.
11
Straight, H.R.L., "Reduction of Oxides of
Nitrogen in Vent Gases," Canadian ~.
Chern. Eng., February 1958.
12
Liimatainen, R.C., and Mecham, W.J.,
"Removal of Halogens, Carbon Dioxide
and Aerosols from Air in a Spray
Tower," JAPCA ~ (1), 1956.
9
-------
Section Nine
ADSORPTION
lJaslc Concept::; of Ad:;oI'Pt1on on Act1 vated Carbon
ITinclples of Adsorption
Application of Adsorption to Air Pollution Control
-------
BASIC CONCEPTS OF
ADSORPTION ON
ACTIVATED CARBON
"Basic Concepts of Adsorption on Activated Carbon"
Reprinted with permission of Calgon Corporation, Pittsburgh, Pa.
PA.C.ge.32.5.7J
t@JJ1D') PITTSBURGH ACTIVATED CARBON
~" DIVISION OF CALGON CORPORATION
SUBSIDIARY OF MERCK & CO:,INC.
CALGON CENTER, BOX 1346, PITTSBURGH, PA. 15230
-------
WI: have attempted in the following discussion to out-
line in a simple manner the answers to two questions
we arc frequently asked:
"WHA T IS ADSORPTION?"
"WHAT IS ACTIVATIm CARBON?"
Tho:so: lluestion~ do not have simple answers because of
Ih.: lack of any single unifying principle which can ex-
plain .tli adsorption phenomena.
Through the years, by working wilh Activated Car-
hon both in the research laboratory and in the field, we
have eVI'lvl'd our own interpretation of fundamental
concepts which we present herein. Some of what we say
must be presented without rigorous proof; but the sum-
total. we feel, is a logical, self-consistent theory which
has expl~lined a host of experimental observations and
has gUided us to the successful solution of many prac-
tie~JI pil'b!l'rm.
Though carbons produced by other manufacturers
haw been mentioned by name, these are included only
as examples to show the range of properties found. No
ilJlplil...!lions arc made abollt the relative worth of these
CMbons as e.lch has its particlliar mcrits in respect to
specific applications.
1
-------
Section I
SURFACE PROPERTIES OF
ACTIVATED CARBON
The twp principal physical features of activated carbon,
uplln which ih pwperties uf commercial val,ue depend,
.Ire surLlce and pore structure, The role that surface
plays COlli ollly bl' understood in relation to the phe-
noml'fHHl of adsorption,
A.
'I m: ~'\ll!RE OF ADSORPTION
Adsorptilln IS usually explained in tel ms of the sur-
IdLL' knsiol1 (or energy per unit area) of the solid,
Moleeule'i In thl' Intn.,)r of any solid arc subjected
to equ.1I 101LL'S in .111 directions, whereas molecules
111 th,' surfael' ;11"1: subjected to unbalanced forces.
rhe r,'sulting Inward forces can only be satisfied if
olhlT nlOkcules, u'iually gaseous or liquid, become
.Itt.lched to tlH' surface, The attractive forces are
the same ,IS tlwse responsible for surface tension
,Ind eond,'ns.\tiol1 in liquids, They arc relatively
\\l'.11.. and are called Van der Waal's forccs, When
such forces are In\'olved. the adsorption is term cd
"ph) sieal", .lnd the adsorbed molecules arc easily
released lrom the surface, i,e" "desorbed" In con-
trast tl! thi'i. chemisorption is the result of chemi-
e;1I Inler;lelion with surface mokcules, Stronger
fOICt's OIl'e 'InvlIl\'ed, and the process is irreversible;
thdl IS, the nwleeulcs originally adsorbed arc re-
u)\L'lul in the form of I.:ompounds I.:ontaining
;,tOIll', of the ;idsorbent, l30th physical and chemi-
SOll>llon ;11,' inclut!ul In Ihe genn.1I term "sorp-
tIOn"
I h"1 l' is .II 1'1'<',,'nl no known method of meas-
urlll.l' Ih,' Sill L,Cl' tl'l1sioll III .I solid directly, How-
L'\ el, till' 1,)1011 'UI lOll'\' l'nngy IS equal to the prod-
uct 0' I he SUI i ael' ,'nel n pn unit area and the
tlll.lI SUI Llc\' .Ire;\. h'r this leason, high surface
.11";\ " Ih,' pI iu),' l'lInsidnatio!l 111 adsorption; and
.Iell\dted e,lIhon IlSu;lIly have sudOll.:e are;\s in the
,)( dLT (,I 500-14\)() "Iuare meters per gram,
n.
I\ILASlJRl'MENT 01<'
SlJRFAn: AREA OF SOLIDS
1,1 h,' surfal.:e ;11 ,'01 of I.:arbon may be detL:rmined
by th,' Brunauer, Fl11mctt & Teller (BET meth-
odl' The volul1le of nitrogen gas adsorbed at
Illjuid nitrogen temperature (-- I !}YC'.) is meas-
urnl at various pressures, i\ 'plot of volume ad-
sorbed vcrSII'i pressure at constant temperature
, HI tllldllL'I, I 111II1L'II .IlId I die-I, J, "I". ('hem. Sot', 60. ,1()<)
il'IIH)
is called an adsorption isotherm, By applica-
tion of the BET equation to the isotherm, it is
possible to calculate the volume and, hence, the
surface area of a layer of nitrogen one molecule
thick, The surface areas, usually expressed in
square meters per gram, of some commercial
activated carbons arc listed below.
TABLE I
SURFACE AREAS OF ACTIVATED CARBON IM'JR')
PCC SGL Bituminous coal 1000-1200
PCC BPL Bituminous coal 1000-1200
PCC RB Bituminous coal 1200-1400
PCC GW Bituminous coal 800-1000
Columbia CXAJSXA Coconut shell J 100-1300
Columbia AC Coconut s'hell 1200-1400
Columbia G Coconut shell 1100-1150
Darco S 51 l.ign ite SOO- 550
Darco G 60 Lignite 750- 800
Darco KB Wood 'J50-1000
Hydro Oarco I ignitc 550- 600
Nuchar Ayua Pulp mill residuc 550. (,~U
Nuchar C Pulp mill rc,siduc 1050-1100
Nu<:har (vanou,,) Pulp mill residue 300-1400
Noril (variou~) Wood 700-1400
2, The Harkins-Jura gas method may also be em-
ployed. In the case of activated carbon, it has
been found that adsorption from solution of
small molecules such as iodine gives a good
approximation of the surface area. The follow-
ing methods~ are good only for non-porous
solids.
Sedimentation methods
Permeability methods
Light and electron microscopy
X-ray low-angle scattering
Co
THt: CHEMICAL NATURE
OF THI<: SURFACE
Adsorption may be inlluenced by the nalure of the
surface and the adsorbale, In the case of solution.
it is oftl'n said that "like" dissolves "like"; anti we
may also ;Ipply this principle to adsorption and say
that "like" adsorbs "like ", polar surfaces prefer-
ring polar adsorbates and so on, Polar compounds
arc those which may exist as positive or negative
ions or are inlluenced by an electric field. Most
inorganic compounds fall into this category. as
well as certain unsymmetrical organic molecules.
A pure carbon surface is considered to be non-
polar; but in actual practice, some carbon-oxygen
complexes are usually present which render the
surface slightly polar. Since there arc no satis-
factory methods of determining quantitatively the
polar character of a surface, the above statement
of principle is relative, In general, activated carbon
, EmmL'tt, I'. H:, "Catalysis". New York, 1954.
2
-------
IS a poor adsorbent of inorganic electrolytes. Due
to its higher surface area per gram, activated car-
bon will adsorh aromatic and unsaturated ali-
phatic compounds to a greater degree than silica
gel which has a polar surface. However, silica gel"
exhibits pronounced selectivity for unsaturated, in
preference to salll~ated compounds, which is not
shown by carbon. This is probably due to the polar
nature of the C=C double bond.
Certain carbons, especially of vegetable origin,
have an alkaline ash and an alkaline surface which
has definite hydrophilic (water adsorbing) proper-
ties as will he shown later in its effect on water
isotherms. Polar surfaces of this kind may influ-
ence the ;lds'lrptiol1 of polar bodies; e.g., unsatur-
atcd organic compounds, dyes ancl col(!r bodies,
h\.Jt as yet, there IS insulli":lent data to correlate
such observations.
It should he l'mphasil.ed that for activated car-
hon in gcneral. the chemical n.!ture of the surface
is of minor signific;l;JCl' and should be considered
sc!:ol'dary in ~elatloll to the major factor, magni-
tude of surf.l!:e area. Thou!!h many investigators
h;lVl' It,ok,'d to th,' chcmical nature of the s.urface
(sudan' complex, activated sites) for the explana-
tion of anomalies of adsorption. a more satisfying
and logical explanation can he found in a "molec-
ular screening" concept to be discussed in a later
section.
, Lewis. (;,lIiland, Chcrtow aPod Cadogan, Ind. Eng. Chern.
41, 1~19 (1950)
Section II
PORE STRUCTURE
PROPERTIES OF
ACTIVATED CARBON
A.
CAPILI.ARIES IN CARRON
Thc suhmit:ros":'lpic structure of activated carbon
IS not known with ccrtainty. hut it IS probably com-
posed of amorphous particles randomly distributed
10 givc a complex network of irregularly-shaped
and partly Interconnected passages between the
particlcs. For the purpose of arriving at a ,quanti-
tative concept oj" size. however, the assumption
may be made that these passages or pores are cylin-
dncal in shape.
Evidence for the existence of pores in activated
carbon is to be found in the following facts.
3
1. Large quantities of vapor or liquid are adsorbed
(e.g., 60-70 g. CCI. per 100 g. carbon) without
appreciable change in the size of the granule.
2. The difference between the granule volume and
the actual volume of the carbon as measured by
helium displacement is usually considerable.
3. It is possible to force mercury under pressure
into evacuated carbon granules.
4. When the desorption isotherm docs not coin-
cide with the adsorption isotherm, it is regarded
as evidence that fine capillaries are present.
This phenomenon, known as hysteresis, usually
occurs when condensible vapors are desorbed
from activated carbon, as shown in Figure I.
Figure t
v
P/Po
5. The large surface area of activated carbon com-
pared to the small geometric area of the parti-
cles or granules requires the existence of con-
siderable internal surface which can only be
provided by small capillaries.
A variety of research techniques has shown that
the pores in activated carbon are divided into two
distinct classes in respect to size. The more im-
portant pore system, since it contributes nearly all
the surface available for adsorptive purposes, is the
smaller or "micropore" system. This system is
largely the product of the activation process. The
larger capillaries, called "macropores" are more
dependent on the raw material and preliminary
manufacturing process, e.g., grinding and agglom-
eration of raw material. These pores contribute
very little to the surface area but serve as avenues
of entrance to the interior of the gross carbon par-
ticles. These two systems are discussed separately
below.
B.
MICROPORE STRUCTURE
Micropores may be arbitrarily defined as- pores
whose diameters range from 10 to 1000 A. The
most satisfactory method of characterizing micro-
-------
pore size in activated carbons is that described by
J uhola & Wiig', using the water desorption iso-
therm. As already mentioned, most activated car-
bons possess a surface which water does not wet
readily. Water molecules prefer to associate with
each other, rather than with carbon. Consequently,
at low vapor pressure very little water vapor is
taken up by activated carbon. At higher vapor
pressures water is readily adsorbed. but this is be-
lieved to occur by condensation in the pores and
not by adsorption on the surface. On desorbing,
hysteresis is noted. It is believed that the desorp-
tit'n isotherm represents the equilibrium 'involved
in emptying pores. and that application of the
Kdvin Eljuation to the desorption branch will per-
mit " ljuantitativc evaluation of pore size. This
appears to be suhstantiated by the fact that surface
areas c,dculated from the resulting pore size dis-
trihution arc in l'ssl'ntial accord with those meas-
ured by the BET IlIl'Ihod,
I. Determination of Micropore Structure
by the Kelvin Equation
The Kelvin Equation is derived from thermo-
dyn,lmic considerations of the free energy
changes involved in the process of transferring
liquid frolll unadsorbcd phase to adsorbed
phase in tine capillaries. The equation is as
fl,lIows:
() ---
4 (J v cos e
RT In 1'/1'0
Where ()
pore diaml'ler
surface tension of adsorbed water
molar volume of adsorbed water
c'lrbon-watcr contact angle
g,IS constant per mole
absolute templ'rature
v,lpor pressure of water
satlll ;Ition vapor pressure of water
"
V
H
R
T
P
I'll
If 'T, \" COS H. R and 'I' arc considered constant.
the l'lluatll'n reduu:s to the '>implc form
f)
I
or -
IJ
k In 1'/1'0
k In 1'/1'0
Th,' rec.:iprol'al of the pore diametcr is propor-
ti,'n,d to the natural logarlthlll of the relative
vap,Jr pressure (P/I'o). Pore diameter values
may be 'Uperlll1po,>ed on the P / Po scale of the
W,ltcr isotherm to give a reasonable indication
of th,' POI',' sile distribution in the microporc
lan!.:e. ;\oo\'C 1'/1'0 c::- 0.99,'ln 1'/1'0 and liD
app'ruach 0, () r;ipidly approaches infinite size
and .lc.:eur.lcy in pore diametcr measurement
heCllmcs I','or. Consequently. rclipble pore di-
;lllIetu v;dues gr,'atl'r than 1000 A arc difficult
tp ohtaln by means pI' the Kelvin Equation.
, Jllhul., .\ WI,!: J. Alii. (,h"II'. Sm'. 71, ~lIh') (1')4'1)
2. Interpretation of the Water Desorption
Isothenn by Inspection
Activated carbons are readily differentiated by
water isotherms. The relationships between
structure and adsorptive tests will be developed
in Section III. However, the manner in which
Iodine and Molasses Numbers are affected by
the shape of the water isotherm may be illus-
trated by the following diagrams. The left-hand,
middle and right-hand portions of the isotherms
will be referred to as regions I, 2 and 3 respec-
tively.
Figure 2
Figure 3
v
P/Po
Figure 4
Figure 5
.-
....-
...-
...-
,
,
.
I
I
I
,
,
#'
Figure I)
Let us assume that the carbon in Figure 2 has
an iodine number of 1000 and molasses num-
ber of 150. If the steep part in region 2 is
raised as in Figure 3, the result will be an in-
crease in iodine number, say, to 1200 with no
change in the molasses number. If, however, the
slope in region 3 only is increased as in Figure
4, there will be little change in iodine number
4
-------
but appreciable increase in molasses number,
say, to 200. Slight movement of the steep part
in region 2 to the right as in Figure 5 should
result in a decrease in iodine number with little
change in molasses number; but if this is car-
ried further. a point will bl' reached where a very
large inl:rease in molasses number will occur
due to enlargl'ment of 1'01 es beyond the mini-
mum diaml'ler for nll>lccul.lr screening of mo-
lasses color bodies. Figure 2 would correspond
to BP carbon. Figul"C 3 to Columbia nutshell
and Figure 4 10 SCi. In the case of RB and de-
colorizing crrbons with high molasses numbers,
the slope in rq!,ion .\ is l'xcept ion ally steep. As
.\ gl'nl'l al rule. the steeper the isotherm in re-
gion J. Ihe grl',lter will be thl' dewlorizing pow-
er of the c.lrbon.
Due 10 I he hydrophobic nature of most ear-
hon SUrL\Cl's. thc isotlH.:rm in rcgion I is prac-
tically horizontal. However, a hydrophilic sur-
face. I:aused perhaps by ionized or polar groups
is recognilable by the fact that thc isotherm has
an appreciable slope at low vapor pressures and
approaches the origin at an angle. as illustrnted
by the iSl)therm of Darco carbon (Figure 6).
When this occurs. thl' lower part of the iso-
therm (region I) c.lI1not be used to evaluate
realistic p~)fe diameters. Fortunately, this hy-
prophilic tendenc)' (;111 usually be destroyed for
experil1H:ntal purposl's by acid or water extrac-
tion and calcinatil'n l,f the carbon.
('.
MACR(WORE STRUCTURE
Since pore diamclers gn:ater than 1000 A cannot
be cakulatl'd with accl'racy from a water isotherm,
an alternative lIIethod:' of measUi ing macro pore
diameters has been devised. Macropores ilre ~Irbi-
trarily dc!inni as porl's gr\:atrr than 1000 A in
diallieter. The samp1\: is eVill:ualed and the volume
of mercury which penetrates Ihe e;lrbon at varying
pressures, is r\:cunlcd. By mt:,lns of the "capillary-
risc" equation.
.ja <:ost-J
[) -~
Wht:re
p
t-I --: earoon-mercury contact angle
cr -::-c su rf ace tension of mercury
P ---- "f'plied pressure,
the recorded pressures arc converted in!O pore
diameters. 1 ht: range normally covered IS from
100,000 A. the pore diameter into which the mer-
cury will ,penetrate at atmospheric pre~sure, down
to 1000 A. the pore di.\llIeter Into whIch mercury
will penetrate at 2,000 psi. If desired, however, the
range may be extended 10 smaller diameters by
application of higher pressures and. thus overhlp
the micropore Sill' distribution obtall1ed from the
waler isotherm.
'Rilles "11<1 Iha~e, Ind. .~II~. ("h"III., AIl,,1 hi 17,7112 (1945).
s
The contribution of macropores to surface area
and adsorptive capacity is very small. For this rea-
son, the presence of macropores in carbon may in
certain cases be a distinct disadvantage since ex-
traneous pore volume results in unnecessary loss
of density. However, in applications where diffu-
sion is a factor controlling rate of adsorption, e.g.,
in adsorption from solution, large macropores may
well be an essential feature of carbon structure.
D.
THE PORE SIZE DISTRIBUTION
1. Total Pore Volume
Since mercury penetration data show only
change in volume with pore diameter, the total
pore volume of the carbon, as outlined by mer-
cury at atmospheric pressure. must be obtained
in order to fix the upper limit of the complete
pore size distribution. This is accomplished by
two measurements.
a. The volume of mercury which the sample
displaces is measured and represents the vol-
ume of the carbon granules. When this meas-
urement is made at atmospheric pressure,
only the largest pores, those greater than
106.000 A (which are mainly the result of
surface roughness of the particles), are filled
with mercury, just as at the start of the mer-
cury penetration measurement.
b. The volume of helium which the sample dis-
places is measured. Since helium penetrates
into the smallest pores, the volume measured
is that of the carbon skcleton. The difference
in volume is then the total pore volume. By
deducting the successive volume increments
measured by mercury penetration from the
total pore volume, the macropore size dis-
tribution' may be plotted.
2, Pore Size Distribution
Between 10 and 1000 A, therefore, the pore
size distribution is calculated from the water
isotherm; and between 1000 and 100,000 A
(.1-10 microns) from mercury displacement,
helium displacement and mercury penetration
data. Since two different theoretical concepts
Figure 7
from He and Hg displacemenl
v
--
'"
M a<:ropores
10
1000
100,000
"ore Diamcter, A
-------
~trt: involved -in the determination of the com-
plete curve. the smoothness with which both
halves extrapolate into each other is a measure
of the validity of the technique as a whole. Sur-
prisingly good closure of the curves is found in
most cases, considering inaccuracies which may
be Introduced in sampling or in the determina-
tion of pore diameters in the upper portion of
the water isotherm. The salient features are il-
lustrated in Figure 7.
3. Surface Area-Pore Diameter Curves
If pores arc regarded as being split up into
cylindrical segments of fairly uniform diameter,
and the pore volume associated with any par-
ticular segment is determined from the pore
size distribution, it is then possible to deter-
mine the area of the walls of the segment
through simple geometry by use of the rela-
tionship.
Figure M
f\V
6.A
"","'-------...
: '
- i:'r~h:~:,~ ~ ~------- }
or 6. A = --- I
D ,------, --1..
, '
"", ".1>'
-- - ---
The ,Ireas of all the segments may be added or
integrated starting with those of large diameter,
and the figures obtained then represent the cu-
mulative area of all the pores greater than the
particular pore diameter down to which the
summation is carried. The cumulative surface
areas are plotted idtnt'tCI. A
Section III
PORE STRUCTURE AND
ADSORPTIVE PROPERTIES
A.
MOLECULAR SCREENING-CONCEPT
OF "A V AILABLE" SURF ACE
If the chemical nature of the surface is regarded as
playing a secondary role in adsorption, the adsorp-
tive properties of activated carbon can be attrib-
uted mainly to surface area and pore structure.
It is apparent from pore size distribution data
that the major contribution to surface area is lo-
cated in pores of molecular dimensions. It seems
logical to assume that a molecule, because of steric
effects, will not readily penetrate into a pore small-
er than a certain critical diameter and will be ex-
cluded from pores smaller than this; hence. the
concept that molecules arc "screened out" by pores
smaller than a minimum diameter which is a char-
acteristic of the adsorbate and related to molecular
size. Furthermore. for any molecule the effective
surface area for adsorption can exist only in pores
which the molecule can enter.
Figure 10 attempts to illustrate this concept for
the case in which two adsorbate molecules in a
solvent (not shown) compete with each other for
adsorbent surface. Because of the irregular shape
of both pores and molecules and also by virtue of
constant molecular motion, the fine pores ate not
blocked by the large molecules but are still free for
entry by small molecules. As a contributing factor.
the greater mobility of the smaller molecule should
permit it to diffuse ahead of the larger molecule
and penetrate the fine pores first.
This concept of "available" surface. that is, sur-
face area accessible to the adsorbate molecule,
when applied in conjunction with the surface area-
diameter curves referred to in Section 11, provides
a powerful tool by means of which apparently un-
related adsorptive properties of activated carbons
may be satisfactorily accounted for. However, in
the event that critical comparisons of different car-
bons arc to be made on this basis, it is desirable
that secondary factors. such as the chemical nature
of the surface. be held as constant as possible
either by appropriate treatment of the carbons con-
cerned or by specifying uniformity in raw material
and method of manufacture of the carbons to be
compared.
6
-------
----
--.....-..
'--
.~..,",,:.""'"
CONCEPT OF MOLECULAR SCREENING
IN MICROPORES
.
Macropore
- J -- - - -
l'
Micropore
Area available 10
both adsortJales and
aolvent
Area
available
only 10
aolvent
Figure 10
7
-------
- - - --- P!a~A
EU:CTRON MICROSCOPE PHOTOGRAPH OF A PITTSBURGH ACfIV A TED CARBON
While the arli_t', conception on the preceding page shows a cross sectional view, the above illustration is un actual photograph.
Light arcas arc pore openings. Ourk arcas represent the curbon skeletal structure.
8
-------
B.
CORRElATION OF AI>SORI'HVE
PROPERTIES ANI> PORI': STRUCTURE
Thc aelll"\ ,lit' rt'knl'd 10 :IS iodine nUI11-
hn, 11I,'thykll<' hlol' 110111 I>t' I ,lIld :,0 on. To illus-
I I :11,' III IW ad,," 1>:11,' lIulnl>l'I' .II,' C"I n:lat,'d with
pOI<' \lrlll'lull:. Ih\' slIILln: art':' 111 porc'; gre " t\
,,,. !Jc' III
I IgllfL' I ~
"'v"rc J 1
--
IlHllne
No.
10..1111('
N"
-"---- - ---
_m_J
\lIrf.l\ (' ,114..',1 III
1''''''' > III ,\
-\v Ikv "
\111 tact' :lIca If)
1'''' '" > I ~ !\
!\ v Ill'v 1\
The following results have been obtained" using
this technique.
I\do;orbllte
hKline
Potassium permanganale
MClhylene hlue
Frythro\ine rcd
Mol,,\se\
TABI,E :I
Minimum Pore
l>iameter, A
Equation of I.\ne
y::: 17 + 1.07X
Y = 4,8 + n.5nX
y O~ 0.4 + n,34X
y:c= 17 + 0.30X
Y c.= 129 + X
10
10
15
19
28
The correlations arc shown in f'igures 14 to 18,
Figure 15
600
KMnO,
No,
Surface Area> 10 A
hgure 17
200
FR
No,
600
Surface Area> 19 A
Figure 14
IOCIO
Iodine
No.
1000
Surface Area> 10 A
Figure 16
300
MB
No.
Surface Area> 15 A
Figure 18
300
Mol
No,
9
.. A. J. Juhol;I, Report 400 S'I. Nov, I, 1'151.
Surface Area> 28 A
-------
All of the ahove molecules were adsorbed from
aqueous solutions where the pH was essentially
ncutr,JI. If adsnrption is carried out in solutions of
varying pH. considerable discrepancy in capacity
may be ,lI1ticipatl'd. since pH affects both the solu-
bilit y and ionic eharacter of the adsorbate. It is
Ihcr~'fl)rl' neec'ssary tn exert cautinn when predic-
linn~ of qruetur..: from adsorptive properties arc
attempted. unle~s there i~ reason to believe that the
I'll PI' the solutions in contact with the carbon is
fairly constant.
Onee the minimum pore diameter for a particu-
lar adsorbate h;IS been established. the capacity of
other earhpns for this adsorbate may be predicted
from their surfaee area-diameter curves. Converse-
ly. if several adsorbate numhers are known for a
paniculal c.III"'I1. the surf;\ce area in pores greater
than Ihe mil1imum pore diameters previously es-
tablished f<)r these adsnrhates may be predicted.
PrOl Iding that the .Idsmbat..:s selected have mini-
mum pore diaml'ters which arc well-spaced and
l:ovcr a fairly wide range, say 10-40 A. it is possi-
bk by this means to rl'eonstruct the surfacc area-
diameter eurVl' fnr a carhon whose pore size dis-
tnbution is un~n<)wn.
Fnr example, given a carhon with the following
adsorbate numt)('rs. and applying the equations in
Table 3. surfal:e areas arc thcn tabulated as fol-
lows:
TABLE 4
Ad".rbate Area in pores greater than
Ad",rbale Number 10 A 15 A t9 A 28 A
Iodine 12(,2 1163
Methylenl' hlllC 160 10!>O
1:'1 ylhrO\ine rL'd 240 743
Mula"e, 400 291
The resulling surfacL' arL'a-dlamder eurve is plot-
led in l'i"lIre I I). and thc' dottl'd line shows the
eUl ve ,)bt~ined from the pore size distribution.
hgllre IlJ
IO()()
Surfal'c
Area
10
.ltl
)()
Pore Diameter, A
The application of structure correlations to other
adsorbate systems has shown that streptomycin ad-
sorption corrClates with surface area in pores great-
er than 18 A in diameter (Figure 20), and nylon
salt adsorption with surface area in pores greater
than 20 A (Figure 21).
Figure 20
Streptomycin
Capacity
Surface Area in pores> 18 A
Figure 21
Nylon
Salt
Capacity
Surface Area in pores> 20 A
A more rapid but less accurate method of corre-
lating structure is to plot adsorbate numbers as a
function of other adsorbate numbers whose mini-
mum diameters are already established. By this
mcans, aniline adsorption is shown to correlate
with iodine and methylene blue '1umbers for a
minimum pore diameter of 10-15 A. (Figures 22
and 23) .
Figure 22
60
Aniline
No.
1400
Iodine No.
10
-------
Figure 23
(,(J
Aniline
No.
360
1\1 I! No,
Cycll!hexylamine adsorption apparently correlates
with i9dme number for a minimum pore diameter
of lOA.
Two other hits of evidences favoring thc molec-
ular scrl'Cl1Ing concept arc:
I. The development of adsorptive capacity for suc-
cessively larger moleculcs as activation pro-
ceeds, on the assumption that activation elfects
Ihl' progressIve' enlargcm,'nt of small pores.
2, '1 Ill' sl'par;ttlon of g,lses and vapors of varying
nwlecul.lr si"e hy the process of sclC'Ctive ad-
">rpti'Hl hy so-called "molecular sieves"..
Co
!\I>SORltTION 01< MIXTllRES
Whl'n more than olle adsorhate: is present in solu-
tion. It IS inevitable that there will be competition
1'01 availahle surface, In the ahsenee of molecular
screenll1g, the ,Ivailable surface will be identical
for all adSl!rhall's com;crned. However, if molecu-
lar scn:cning "ccurs, the availahle surface may not
he the ~ame fpr cach molccule, in which case pref-
erential adsl!rptipn of a particular adsorbate within
a narrov. pprl' sizc range i~ a possibility.
Fpr example, the adsorption of hydroxymethyl
furfur.1I (HM 1-') in a'llll'l!us solution corrFlates with
surface area in pores greater than J 5 A, and ad-
sorption of proleln :Ind color boodies with surface
arl',l In PPICS grl'atl'!' th;1O 2.1 A. However. when
:IUSOI pt ipn pI' H M I. ta!..l's place in the presence of
!,rptem and l'l''''r bpdies. it is necessary to postu-
latl' :1 ilIa XI 11111 III. as well ;IS a Illinimum, pore di-
;II\1I:tl'!' In prdn to dkl'l s;11 isfactory correlation.
H M I" ,IUS,!rpl ion has heen correlated with surface
area In pon's hetween I Sand 23 A, and it there-
fore ;'prears that adsprp'ion in I;Hger pores is rc-
stricled hy ePlllpeting prntelO and color bodics, as
illllstl atd by analogy in J-igllre In.
D.
t:Nt:R(;Y 01< !\I>SORPTION
When ,\ gas or vapor is adsorhed on the surface of
al'livated carhon, latent heat is released in a similar
manOl'r as when steam condenses or water turns to
'''Molecul.1I Slt'V", (or Sclecl,ve Arplion", t ," E I, Th,;
difference, E)-E,. is referred to as the net he
-------
It should be pointed out that the presence of
considerable high energy surface in activated car-
bon may not always be advantageous. Strong ad-
sorption in fine pores is associated with high re-
tentivity. the ability to retain the adsorbed layer
under specified conditions favoring desorption. In
cases when: solvent vapors already adsorbed must
oe recoVl:red for economic reasons, it may be cor-
respondingly more difficult to accomplish this if a
fine pored carbon is employed.
E.
THE PREDICTION OF
ADSORPTION ISOTHERMS
Althuugh satisfactory techniques are available for
determining the pore size distribution of an acti-
vated carbon from either its water or nitrogen de-
sorption isotherm, it is not yet possible to predict
adsorption isotherms from the pore size distribu-
tion alone. Nevertheless, the generalized adsorp-
tion correlation of Lewis et al,a which is based on
the polanyi adsorption potential theory. can be
used to investigate the relationship between tilled
pore volume and adsorption-free energy. It has
been remarkably successful",)l1 in correlating the
adsorption isotherms of a large number of gases
and vapors on a single activated carbon, and in the
absence of experimental data, its use is recom-
mended for preliminary estimation of the adsorp-
tion capacity of gases.
'" Grant, Manes, and Smith, A. I. Ch. E. Journal, 8. 403
(1962).
12
-------
PRINCIPLES OF ADSORPTlpN
J. J. Bolen*
I
INTRODUCTION
The adsorption process can be applied to the
collection and measurement of gaseous radio-
nuclides. At present, adsorption techniques
for radioactivity measurements are used
primarily for monitoring inplant operations
(e. g., monitoring gaseous releases from
reactor and fuel reprocessing operations).
However, adsorption coupled with filtration
methods can be used for measuring environ-
mental levels of such radionuclides as iodine
and radon.
This outline presents a detailed discussion of
the adsorption process along with its appli-
cation to the sampling and measurement of
gaseous radionuclides.
II
BASIC PRINCIPLES
Adsorption is the phenomenon by which gases,
liCi.lids and solutes within liquids are attracted,
concentrated and retained at a boundary sur-
face. The boundary surface may be the inter-
face between a gas and liquid, liquid and liquid,
gas and solid, liquid and solid, or solid and
solid. Of the various boundary surfaces, the
adsorption mechanism between liquid and
solid and gas and solid have received the most
attention. The former with respect to removal
of substances from 30lution with a solid absor-
bent (e. g.. purification). and the latter with
respect to removing gaseous pollutants on
solid absorbents of high surface area. ( 1)
A solid adsorbent is composed of a type of
crystal lattice structure. The atoms at the
surface of the lattice are arranged in a
regular sequence which is dependent on the
particular solid's crystalline structure. The
valence or other attractive forces at the sur-
face of a solid are unsatisfied or unsaturated
due to their lack of being united with other
atoms. As a result of this unbalanced con-
dition, the solid surfaces will tend to satisfy
their residual forces by attracting and re-
taining gases or other substances with which
they come in contact. This surface concentra-
tion of substance is the adsorption process.
'-Sanitarian, Environm-ental Radiological Health
Training Section, Training Branch,
Division of Radiological Health
The attracted substance' is known as the ad
sorbate, while the substance supplying the
surface is called the adsorb~nt.
With reference to air, adsorption technique
are commonly used for collecting a specific
gas or combination of gases. A typical pro
cess consists of passing a gas stream throu
a container filled with an adsorbent such as
activated charcoal, alumina, or silica gel.
The gas is bound to the adsorbent by molecu
forces and if condensation does not occur, t,
gas remains p~sically and chemically un-
changed. Following collection, the gas may
be removed from the absorbent for analysis
or ultimate deposition by application of heat,
passing inert carrier gases through the
system, or chemical treatment.
Adsorption can be distinguished from absorp'
tion. In absorption the material is not only
retained on the surface, but it passes through
the surface and is distributed throughout the
absorbing medium. The term absorption in
many cases implies a chemical reaction
between the absorbing medium (absorbent)
and the collected substance (absorbate). For
example, water is absorbed by a sponge and
anhydrous calcium chloride. However,
acetic acid in solution and various gases are
adsorbed by activated carbon. Often when thE
true process is not known the term sorption i
applied. (2, 3)
III
TYPES OF ADSORPTION
Investigation of the adsorption of gases on
various solid surfaces has revealed that the
operating forces are not the same in all
cases. Two types of adsorption have been
recognized, namely; 1) physical or van del'
Waals adsorption, and 2) chemical or
activated adsorption.
A Physical Adsorption
In physical adsorption the attractive forces
consist of van del' Waals energy, dipole-
dipole interaction, and lor electrostatic
-------
Principles of Adsorption
ene rgy, These forces are similar to those
causing the condensation of a gas to a liquid.
The process is further characterized by low
heats of adsorption, on the orde r of 2 - 15
kilocalories per mole of adsorbate, and by
the fact that adsorption equilibrium is re-
versible and rapidly established.
Physical adsorption is a generally occurring
process. For example, this is the type of
adsorption occurring when various gases are
a~sorbed on charcoal. If the temperature is
low enough, any gas will be physically ad-
sorbed to a limited extent. The quantity of
various gases adsorbed under the same condi-
tions is roughly a function of the ease of con-
densation of the gases. The higher the boiling
point or critical temperature* of the gas, the
greater is the amount adsorbed. This concept
will be discussed in more detail subsequently.
B Chemical Adsorption
In contrast to physical adsorption, chemical,
or activated adsorption is characterized by
high heats of adsorption, on the order of
20-100 kilocalories per mole of absorbate,
and it leads to a much stronger binding of
the gas molecules to the surface. Heats
of adsorption are on the same order of
magnitudes as chemical reactions and it
is evident that the process involves a
combination of gas molecules with the ad-
sorbent to form a surface compound. This
type of adsorption resembles chemical
bonding and is thus called chemical adsorp-
tion, activated adsorption, or chemisorp-
tion. For example, in the adsorption of
oxygen on tungsten it has been observed
that tungsten trioxide distills from the
tungsten surface at about 12000K. How-
ever, even at temperatures above 12000K,
-. - -- ----- -- - ----"---- .
*Cr-itkal tpmlwrature may be defined as that
t('IIlIH'ratun> above which it is impossible to
liquify a gas no matter how high an £>xternal
prpssul'P iR applied.
.)
oxygen remains on the surface apparently
as tungsten oxide. Additional examples
of chemical adsorption are the a.dsorption
of carbon dioxide on tungsten; oxygen on
silver, gold on platinum; and carbon and
hydrogen on nickel.
A comparison of physical and chemical
adsorption can be made by considering
the adsorption of oxygen on charcoal. If
oxygen is allowed to reach equilibrium
with the charcoal at OOC, most of the oxygen
may later be removed from the charcoal
by evacuating the system at OOC with a
vacuum pump. However, a small portion
of the oxygen cannot be removed from the
charcoal no matter how much the pressure
is decreased. If the temperature is now
increased, oxygen plus carbon monoxide
and carbon dioxide are released from the
charcoal. Thus most of the oxygen is
physically adsorbed and can be easily re-
moved, but a small quantity undergoes a
chemical reaction with the adsorbent and
is not readily removed. In some cases,
chemical adsorption may be preceded by
by physical adsorption, the chemical ad-
sorption occurring afte r the adsorbent has
received the necessary activation energy.
In general, with respect to the adsorbent-
adsorbate pairs, chemical adsorption is
more specific in nature than physical
adsorption. It i8 usually a much slower
process, requiring the displacement or
selection of the molecules where the re-
action is to occur. The chemisorption
process is enchanced at higher tempera-
tures where existing energy barriers
between the adsorbent and adsorbate are
overcome. At low temperatures, chemical
adsorption in some systems may be too
slow to reach a measurable amount. In
many cases the adsorption occurring is a
combination of both types. At low tem-
peratures physical adsorption may pre-
dominate, whereas at higher temperatures
chemisorption may be more prominent.
This situation is true for the adsorption of
hydrogen on nickel. However, due to the
non-specificity of van de r Waals forccs,
physical adsorption may be occurring but
be hidden by chemisorption. Finally,
-------
-----.- ----- -------- -..-----
P rinciples ~_~dSOI:E.!.!~__-
chemical adsorption is usually limited to
the formation of -a single layer of molecules
on the adsorbent's surface, whereas in
physical adsorption the adsorbed layer may
be several molecules thick.
In most of the adsorption equipment in
air pollution control work, physical ad-
sorption plays the most prominent part.
Physical adsorption is also used to a great
extent in the collection of radioactive
. gases. (2,3,4)
IV
VARIABLES AFFECTING GAS
ADSORPTION
The quantity of a particular gas that can be
adsorbed by a given amount of adsorbent will
depend on the following factors: 1) concen-
tration of the gas in the immediate vicinity
of the adsorbent, 2) the total surface area
of the adsorbent, 3) the temperature of the
system, 4) the presence of other molecules
which may compete for a site on the adsor-
bent, 5) the characteristics of the adsorbate
such as weight, electrical polarity, chemical
reactivity, and size and shape of the molecules,
6) the size and shape of the pores of the adsor-
bing media and 7) the characteristics of the ad-
sorbent surface such as electrical polarity and
chemical reactivity. Ideal physical adsorp-
tion of a gas would be favored by a high con-
centration of mate rial to be adsorbed, a
large adsorbing surface, freedom from com-
peting molecules, low temperature, and by
aggregation of the adsorbate into a form
which conforms with the pore size of the
attracting adsorbent. (5, 6)
Several of the above listed variables will now
be discussed in greater detail.
A Adsorption Isotherms
Adsorption processes where physical adsorp-
tion rathe r than chemisorption represents the
final state can be explained in terms ofequili-
brium measurements. For a given amount
of adsorbent with a given surface area the
amount of gas adsorbed is dependent
on the pressure (or concentration) of the
gas surroundingth~ adsorbent. The higher
the pressure or concentration of the gas at a
given temperature, the greater the
amount of gas adsorbed. When an adsor-
bent and gas are mixed, the amount ad-
sorbed will gradually increase while the
concentration of the adsorbate in the
system decreases until the rate of ad-
sorption becomes equal to the rate of
desorption. Thus an equilibrium between
the two phases is established. If additional
gas is added to the system the amount ad-
sorbed will increase until equilibrium is
again established. Likewise, if the gas
concentration is decreased the adsorbent
will lose gas to its surroundings until
equilibrium is again reached.
The relationship between the quantity of
gas adsorbed at various concentrations
or pressures at constant temperature is
called an adsorption isotherm. An adsorp-
tion isotherm consists of a plot of the data
obtained from measuring the amount of
gas adsorbed (e. g., grams adsorbed per
gram of adsorbent) at various gas concen-
tration or pressure (e. g., moles per liter
or atmospheres), as the case may require,
at equilibrium and constant temperature
conditions. Adsorption isotherms are
useful in that they provide a means of
evaluating: 1) the quantity of gas adsorbed
at various gas concentrations, 2) different
adsorbent's adsorptive capacities at
various gas concentrations, 3) the adsorbent's
adsorptive capacity as a function of concen-
tration and type of gas, and 4) the sUffa~e )
area of a given amount of adsorbent. 1, , 3
( 1, 3)
1 Types of adsorption isotherms
The graphic plots of adsorption isothe rms
yield a wide variety of shapes. Six
general types of isotherms have been
observed in the adsorption of gases on
solids. These are illustrated in Figure 1.
In physical adsorption all six isotherms
are encountered, while in chemisorption
only type 1 occurs.
3
-------
~!:!~~iplp~..9[__~~so~pti?~___- p-------
TYPE I
---.- -- -.-
TYPE 2
TYPE 3
~--~-_.
TYPE 4
--- -~ --
& ~
TYPE~ (i
-- -- --- --
4
'C
ell
1:
o
C1.I
'C
oCt
~
9
o
~
( 4)
( 5)
----
(6)
Pressure or Concentration
FIGllRE 1 (1,3)
Gas Adsorption
This type l'C'presents the adHO!'ption
of a single layer of gas molecules
011 the adsorbent. There is no
interaction between the adso!'bed
moll'(, ules.
This isotherm begins like type 1
but is modified at high pressure by
multilayer adsorption. There is
definite interaction betwpen the
layers of adsorbed gas molecules.
This type of isotherm is rar('. It
occurs only when initial adsorption
favors a vcry few strong sitl's. ThC'
interaction betwepn adsorbpd
molecules is so strong that vacant
sitE'S npxt to occupied Sitl'S nrp
strongpr than any othl' I' vacant
siles. In this type of adAorption
the lIumlH'I' of pffl'divl' sites ill-
creases with ('ovC'!'agp of thp
adsorbent.
These two 1l!'P similar to typl's 2
and 3 rcsppdiVt'ly. exc'ppt that thC'y
continue to exhibit adsorption ilt
high rldAorbent coveragp.
This typ" rC'l'>embles type 3 with
monolaypr adsorption fi!'st and
Isotherms
then continued deposition of a
multilayer f11m.
2
Mathematical treatment of adsorption,
process
Many equations have been Bllggested 8S
mathematical expressions for the ad-
sorption process. To date no single
derived expression describes all ob-
se rvE'd adsorptive phenomena. It
appears that the type of mathematical
treatment used is primarily It function
of whE'ther the particular adsorptive
process is monolaye I' or multilaye r in
nature.
a
Freundlich equation
In typC' 1 isotherms tht' quantity of
gaR adF.orbed pf'r unit amount of
adsorbent increases rapicily with in-
creasing preesurt' and thc'n proceeds
more slowly DS thr ab80rhpnts sur-
face becomes cow red with gas
moleculE's. A u8f'ful relationship
for dctt'rmining thP quantity of ge.8
adsorbed per' unit ar~a Or wt'ight of
adsorb('nt ,as a function of prcssurl"
has b{'cn purpoRC'd fI~ follows by
. Frl'undlich.
\.
-------
. _. - -._- -~----"
- -- -- - .~----~-'_.
--~-_.. -"-----.--"---
-- -- ~,:i~~ip~c:~ of_~~s?~J~tio~
x
ken
(1)
whe re:
x
quantity of gas adsorbed per
unit of adsorbent
empirical constants dependent on
the naturt' of the adsorbent. gas.
and temperature
k. n =
c
gas concentration
TI1€' (~(]uation may be evaluatf'd by
taking the logarithm of hoth sides
which yields:
log lOX = 10g]Ok + n loglO('
(2)
When log lOX is plotted against log tOC
a straight line of slope nand y in-
tercept of 10glOk should rC'sult. The
Freundlich equation is of t'mpirical
origin and is only valid for monolayer
adsorption whe rC' the re is no inte r-
action between adsorbed molecules.
The requirements of thC' equation are
generally well met at lower pressures.
However. at higher pressures the
straight line tends to curvp. indicating
that this treatment doC's not have afPH-
cability at highe r prC'ssures. ( 1. 2. . 4)
h
',angmuil" p(]uation
I,angmuir' has devploped a much
bf'tte r f'quation of thf' type' 1 isothC' [.m
from theoretical considC'rations. For
cases whC're all adsorbent siteR are
idl'ntical and therC' is no intC'raction
betwPf'11 adsorbed molC'cules (mono-
laye r adsor'ption). tht' isothC'rm is
exprcsRl'd in the form
X
~L-
I + bp
( :i)
where:
x
=
quantity of gas adsorbt'd pc r"
unit of adsorbent
a,b
= empirical constants dppendent
on the nature of the adsorbent.
gas. and temper::1ture
p
= gas pressure
At any temperaturC' the Langmuir
equation may be verified by dividing
both sides of equation (3) by p and then
taking reciprocals. The result is
L-
X
1
a
+
(b/a)p
(4)
A graph of piX Ver"SUR p should yield
a straight linC' with a slope equal to
bla and y intercept of l/a. StIch a plot
for tbe adsorption of nitrogen on mica
at 900K is shown in Figure 2.
1000
600
PIX
o
o
6
12
18
P
I'IGURE J3)
Adsorption of N2 on Mica 900K
From the graph the val'Jcs of a and b
an' 0.00714 and O. 157 r'cspC'ctiYf'ly.
Hence the adsorption of nitrogen on
mica at 900K C'an he represented by
thl' equation
24
30
36
5
-------
Principles of Adsorption
x =
O.007l4p
l+O.157p
( 5)
The excellent straight line obtained
from this and othe r systems supports
Langmuir's theory of the adsorption
process and his assumptions that the
mechanism is monolayer in nature.
The Langmuir equation is limited in
application to monomolecular adsorp-
tion. It applies equally well to
chemical and physical adsorption
where saturation of the adsorbent is
approached. Like the Freundlich
system, the Langmuir derivation is
less valid at higher pressures be-
cause more than a single layer of
molecules is formed on the
adsorbent. ( 1, 3, 4)
c
Multilaye r adsorption
Multilayer adsorption introduces new
problems and many types of expres-
sions hav€' been developed to explain
the process. A theory proposed by
Brunauf'r, Emmett, and Teller ex-
tends the Langmuir derivation to
obtain an equation for multilayer
adsorption. The equation is based
on the assumption that the same
forces causing monolayer adsorption
are responsible for the multilayer
process. Types 2 and 3 isotherms
are explained on the basis of the
formation of many molecular layers
on the surface rather than a single
one. Types 4 and 5 are characterized
by multilayer adsorption plus con-
densation of the gas in the pores and
capillaries of the adsorbent.
On the theory that more than one
laycr of molecules is formed on the
absorbent, Brunauer, Emmett and
Tcller havc derived the pquation
v
V(pO_p)
I
V ('
n1
t ~C:...!...) -!!.
V c )0
OJ I
(6)
6
where:
v
volume of gas adsorbed per
unit of adsorbent at pressure
p and temperature t reduced
to standard conditions
.
o
p ..
V .
m
saturated vapor pressure of
the adsorbate at temperature t
volume of gas reduced to
standard conditions when the
surface is covered with a
monolayer of gas
e
..
constant at any given temperature
and is approximately equal to
(E1 - EL) /RT
e
E co
1
heat of adsorption of the first
layer
E .
L
heat of liquefraction of the gas
The equation can be evaluated by
plotting p/V(po_p) versus p/po. A
straight line should result of slope
e-l/Vm e and y intercept of 1/Vme.
From these, the values of V m and
e can be found.
Type 2 and 3 isotherms result when
El > EL and El < EL respectively.
The isotherms of type 4 arise when
E 1 > EL and those of type 5 when
El < EL' Although the theories of
multilayer adsorption have been
quite successful in explaining
several of the more complex iso-
therms, they are still insufficient
to account for all the \l.uantitative
phenomena observed. \ 1,2, 3,4)
B Temperature
In adsorption an equilibrium is established
between the gas near the adsorbent and the
adsorbed gas. Under any given conditions
of temperature and pressure, the extent of
-------
adsorption is definite and reproducible.
As would be expected, the absorbent-
absorbate equilibrium is strongly affected
by temperature changes. An increase in
temperature results in a decrease of the
quantity of gas adsorbed and vice versa.
This concept is illustrated in Figure 3.
The magnitude of the temperature effect
can be illustrated by examining the ad-
sorption of nitrogen on charcoal at dif-
ferent temperatures. At 600 mm pressure,
one gram of charcoal adsorbs 10 cc of N2
gas at OOC, 20 cc at -290C, and 45 cc at
-780C3.
't:2
"
.a
~
o
~
0<1:
.
as
t:J
IH
o
t
Concentra~ion of Gas
FIGURE 3
Affect of TentJcrature on Gas Adsorption
C Adsorbate Characteristics
The major adsorbate characteristics af-
fecting the amount of gas adsorbed are the
ease of liquefaction of the gas, adsorbate
size, concentration of the gas, and the
presence of other gases.
1 Gas liquefaction
The specificity by which certain gases
art' adsorbed on solid adsorbents is
illustrated in Table I, where the volumes
of different gases adsorbed by one gram
of charcoal at 150C are tabulated.
Principles of Adsorption
Table 1. (3) ADSORPTION OF GASES ON
ONE GRAM OF CHARCOAL AT 150C*
Gas Volume Critical temperature
adsorbed (cc) (oK)
H2 4.7 33
N2 8.0 126
CO 9.3 134
CH4 16.2 190
C02 48.0 304
HCl 72.0 324
H2S 99.0 373
NH3 181. 0 406
Cl2 235.0 417
802 380.0 430
*Volumes of gases have been reduced to
standard conditions (OOC and 1 atmosphere
pressure) .
Table 1 indicates that the extent of ad-
sorption parallels the increase il)
critical temperature. This correlation
suggests that gases which liquify easily
(high critical temperatures) are more
readily adsorbed. However, it does
not imply that the adsorbates exist
as liquids on the adsorbent's surface.
A similar relationship is obtained with
boiling points. (3)
2 Adsorbate size
The size of the gas molec ule to be re-
moved by adsorption is characterized
by a lower and upper range. The lower
size limit is imposed on physical
adsorption by the requireme nt that the
pollutant must be higher in mOlecular
weight than the normal components of
air. In general. gases with molecular
weights greater than 45 are readily
removed by physical adsorption. This
size includes most odorous and toxic
gBses of air pollution interest. Gases
of interest of lower molecular weight,
such as formaldehyde and ammonia.
7
-------
Principles of Adsorption
may be removed by chemical adsorption
methods using appropriately impregnated
adsorbents.
For the upper limit the individual
particles must be sufficiently small
so that Browman motion or kinetic
velocities will ensure effective contact
by collision between them and the
granular adsorbent. Although mode rate
efficiencies may be obtained for very
fine mists, the upper limit is generally
in the range of molec ular size.
3 Gas concentration
As seen from the examination of ad-
sorption isotherms, the quantity of gas
adsorbed is a function of the gas con-
centration or pressure. An increase in
concentration or pressure in the
vicinity of the adsorbent results in an
ine rease of the total amount of gas
adsorbed.
4 Presence of other gases
Since the presence of additional gas
molecules in a particular adsorbent-
adsorbate system causes competition
for the limited numbe r of adsorption
sites present, the observed effect is
a reduction in the amount of adsorbate
removed.
o Adsorbent Characteristics
Most of the common adsorbents in use
are more or less granular in form and are
supported in a column through which the
gas to be sampled is drawn. Common
adsorbents have the capacity to adsorb
8-40 percent of their weight. An ideal
adsorbent should be granular and of such
size and form that it offers little or no
rE'sistance against flow. It should have a
high adsorptive capacity, be inert and
specific, resistant to breakage, deterior-
ation and corrosion, be easily activated,
and provide an easy release of adsorbate.
Unfortunately, no one adsorbent possesses
8
all these characteristics, so that it be-
comes a matter of choosing the best
adsorbent for the particular job. (5,7,8)
1 Surface area
All solids are capable of adsorbing
gases to some extent. However, since
adsorption is a surface phenomenon,
it is not very pronounced unless the ad-
sorbent possesses a large surface area
for a given mass. For this reason, ma-
terials like silica gel and charcoals
obtained from wood, bone, coconut
shells, and lignite are very effective
adsorbing agents. Since large surface
areas are desirable for extensive ad-
sorption, this factor is of primary im-
portance in determining the amount of
absorbate which can be held by a unit
of adsorbent. Solid adsorbents may
vary in surface area from less than 1
to over 2,000 square meters per
gram. Typical approximate surface
areas of several adsorbents are pre-
sented in Table 2. The latter two sub-
stances owe their high surface area to
their porosity. They are thus capable
of taking up large volumes of various
gases,
Table 2. (1) TYPICAL SURFACE AREAS OF
ADSORBENTS
Adsorbent
2
Area (m fgm.)
Clay
Asbestos
5 - 15
10 - 20
20 - 30
50 - 100
Chalk
Carbon black
Silica or Alumina Ge 1
Activated carbon
200 - 800
500 - 2000
The extent of adsorption can be further
increased by activating the adsorbents
by various methods. For example,
wood charcoal is activated by heating
between 350-10000C in a vac uum, in
-------
air, in steam, and/or in the presence
of other gases to a point where the ad-
sorption of carbon tetrachloride at
240C can be increased from 0.011 gram
per gram of charcoal to 1. 48 gram.
The activation process involves dis-
tilling out various impurities from the
adsorbent, thus leading to the formation
of a larger free surface area for adsorp-
tion. Occasionally, large surface areas
are produced by the original cellular
structure of the plant, as in the case of
coconut shell charcoal. However, the
activation process will increase the
porosity of the material and may,
under some circumstances, cause it to
be less stable as an adsorbent. For
example, if the temperature is raised,
the porous structure of the adsorbent
may aggregate into larger units which
tend to become smooth and inactive. In
many cases the past history of the ad-
sorbent with respect to preparation and
method of activation is just as important
as the chemical characteristics in deter-
mining the adsorption capacity. ( I, 3, 4)
2 Pore size
Often the adsorbent will exhibit an 1n-
he rent preference for the adsorption of
certain gases. This prefe rence is pri-
marily due to such factors as the method
of p1"epnration and activation, and the
chemical natun:> of the adsorbent's sur-
facp. Prepaloation and activation methods
not only may increase total adsorptive
capacity, but they may also affect the
adsorption process with respect to
adsorbate's size. Th(> pore size in the
more porous adsorbents may vary in
diameter from a few to several
hundred angstrom units. This may
become a critical factor in selecting
an adsorbent to remove a particular
adsorbate. For example, iodine may be
adsorbed on an adsorbent with pores of
10 AO in diameter, while methylene
blue is excluded by pores havinf a
diamete r less than about 15 AO. 1)
Principles of Adso~tion-
3
Chemical nature
The chemical nature of the adsorbent's
surface is an additional factor of con-
tliderable importance. It is of particular
interest in chemical adsorption where
a rapid rate and a large degree of
chemical reaction is desirable. In
physical adsorption the nature of the
surface is one of the primary factors
influencing the strength of the adsorbent-
absOl"bate attraction. For example, a
pure graphite surface physically adsorbs
hydrophobic compounds (1. e., water
hating) to a large extent, while oxygenated
surfaces are generally required to ad-
sorb hydrophobic compounds (i, e., water
loving) appreciably at room temperature$!)
V TYPICAL ADSORBENTS
The various adsorbents used in physical ad-
sorption may be classified according to their
degree of polarity. For example, activated
carbon, which is commonly known as a non-
polar adsorbent, is largely composed of
neutral atoms of a single species which exhibit
little polarity. The non-polar adsorbents are
most effective for gross decontamination of
moist air streams containing materials of
little polarity (e. g., organic molecules).
The majority of the commercially important
adsorbents other than carbon derivatives
are simple or complex oxides. Their surfaces
consist of heterogeneous distributions of
charge on a molecular scale. They are
strongly polar in nature. Thesfu~dsorbents
show a greater selectivity thar'iR I,the carbon
derivatives and exhibit a muL~nger
preference for polar than f( ,lar
molecules. In separation l J gases,
the polar solvents are more u.., than
carbon derivatives. However, they arE!
much less useful for overall decontamination
of moist air streams since the strongly
polar water molecules are preferentially
adsorbed. (6)
9
-------
Principles of Adsorption
A Carbon
Various forms of carbon se rve as efficient
adsorbents. It has been shown that the
material from which the carbon is prepared
has a demonstrable effect upon the ability
of the carbon to adsorb various gases.
Carbon prepared from logwood, for instance.,
has approximately twice the capacity for
adsorption as carbon from rosewood.
Similarly, coconut shell is about twice as
efficient as logwood. Strangely enough the
carbon prepared from harder, denser
materials such as peach and other fruit
pits, and coconut shells have the highest
adsorptive capacities. Primary carbon is
not nearly as efficient as activated car/Don..
The adsorbents "activated carbon, "
"activated charcoal, " "active charcoal. "
"active carbon, " "adsorbent carbon"anrd
"adsorbent charcoal" may be activat(ed in
a slightly different manner, but the terms
are gene rally considered synonymolus.
Activated carbon has a high adsorptive
capacity, a high degree of hardneiss,
high reliability and other premirJuIJ,1
qualities. Almost all volatile n1at.erials,
whether they are chemicals or mixtures of
odor-causing substances, are re'tained
within the microscopic poroufd EJtructure
to some extent. The only gs"seous materials
which it will not adsorb very well are low
molecular weight gases su,eh as oxygen,
nitrogen and carbon mono,xide. Activated
carbon finds its major ar,>plkation in
solvent recovery and od or removal. It is
also employed to a limf.ted extent in the
removal and monitorirJg of hydrogen sulfide.
sulfur dioxide and oth er toxic gases.
Activated carbon is riol rhaps the most
widely used of the f Fra'£ent in air pollution
control. The folloA,{ \.. ~ 1bstances are
,,"9 .1
some of those whi.(<,o'\:~..ve been shown to
be appreciably adsorbed upon activated
carbon;
acetic
benzene
ethyl alcohol
carbon tetra-
chloride
methyl alcohol
c;hloroform
acetone
iodine
carbon disulfide
diethyl ether
ammonia
hydrochloric
acid
nitrous oxide
carbon dioxide
acetaldehyde
noble gases
10
B Silica Gel
Silica gel is a representativ~ of the
siliceous adsorbents. Others in this group
include Fuller's diatomaceous earth. other
siliceous earths. and the synthetic zeolites.
Silica gel is prepared by hydrochloric acid
precipitation of silicic acid from a solution
of sodium silicate. The gelatinous pre-
cipitate is freed of electrolytes by washing.
Subsequent removal of the waters of hydra-
tion from the precipitate leaves a very
porous structure. In actuality it is not
a true gel but a hard glassy form of
silicon dioxide of extremely high porosity.
The adsorptive capacity of silica gel is
dependent on the temperature and solution
concentration at the time of precipitation
as well as the subsequent treatment of the
precipitate. The maximum capacity is on
the same order of magnitude as activated
carbon. It has been estimated that the
effective surface area within a granule
one-sixteenth inch in diameter is more
than twenty-one square feet. Silica gel,
as well as other members of this group
of adsorbents, exhibit a greater preference
for polar molecules than does activated
carbon. It has been employed for dehydra-
tion of air and gas streams, dehumidific-
ation and air conditioning. Vapors such as
hydrogen sulfide, sulfur dioxide and water
are strongly adsorbed. (4,6)
C Activated Alumina
Activated alumina (aluminum oxide) is a
represe ntative of the metallic oxide adsor-
bents. Some adsorbents in this group are
more electrophilic in nature than the
strongest siliceous materials. Activated
alumina is prepared by precipitating an
aluminum salt from a basic solution.
The precipitate is gelatinous and highly
hydrated, and subsequent drying and
heating converts the hydroxide to the very
porous and active oxide. The finished
product is a granular adsorbent consisting
of highly porous aluminum oxide in the
tri-hydrated form.
-------
Again the adsorpture capacity and physical
characteristics of the adsorbent are
strongly dependent on the conditions of
precipitation and subsequent treatment.
Activated alumina is primarily used as
a desiccant, catalyst carrier, and catalyst.
Additional applications are similar to those
of silica gel. (4, 6) .
D Molecular Sieve
Molecular sieve adsorbents* are synthetic
sodium or calcium alumino-silicate zeolites
of very high porosity. They are another
representative of the siliceous adsorbents.
The structural formula of a typical
molecular sieve is
Mex/n (AI02)x (Si02)y . m H20
whe re Me represents exchange cations of
charge n; The zeolite is precipitated as
a white powder, bonded with clay, and
formed into roughly spherical beads of
four to twelve inch mesh size. The ad-
sorbent is activated wit,h heat to drive off
waters of hydration. The resulting pro-
duct is a crystalline solid of very porous
structure. Again the adsorptive char-
acteristics are dependent on the method of
preparation.
Molecular sieves can be made very specific
with respect to pore size. This character-
istic gives them the outstanding property of
being specific on the basis of the adsor-
bate's size and shape. Molecular sieves
show a strong preference for the more
polar molecules. For example, these
adsorbents will not adsorb organic
molecules that match their pore size from
a moist Btream of air. The accompanying
water molecules being adsorbed in pre-
ferenct.'. Molecular sieves are truly
selective adsorbents in that they can VII
separate mixtures on the basis of differences
in molecular size, degree of polarity, and
* Often referred to as molecular sieve absorbents.
Principles of Ads0.!p.tion-
extent of carbon bond saturation. In
addition to their selective properties,
molecular sieves possess a high adsorptive
capacity over wide ranges of concentration
and temperature. They also are capable
of removing impurities to extremely low
concentrations. These adsorbents have
been tested successfully on carbon dioxide,
hydrogen sulfide, acetylene, ammonia and
sulfur.dioxide. They show promise for
adsorption of compounds of low molecular
weight. (9)
VI
APPLICA TION OF ADSORPTION TO
RADIOACTIVITY MEASUREMENTS
Current use of adsorption techniques if; pri-
marily orientated toward monitoring such
processes as gaseous releases from reactors
and fuel reprocessing operations in and
around nuclear installations. For example,
radioiodine may be monitored from reactor
and fuel reprocessing operations by fhysical
adsorption on activated charcoal. ( 12 Some
of the quantitative aspects of such a process
have been investigated, (13) Activated char-
coal has also been used by the Public Health
Service's Radiation Surveillance Network
for monitoring environmental levels of
iodine-131. Noble gases such as argon,
krypton and xenon can also be physically
adsorbed on activated charcoal. Since each
of the noble gases exhibits a specific affinity
for the adsorbent, a separ&tion of the individual
gases ca~ b.ij made by chromatographic
methods. 1
At present, the practical use of adsorbents
for collecting and measuring environmental
levels of radioactivity is not widespread.
Limited work has been done on radon adsorp-
tion on activated charcoal with respect to
the uranium mining industry and in combina-
tion with filtration methods for environmental
levels (10, 11)
. .
SUMMARY
The adsorption process is characterized by
either physical or chemical forces. In
some cases both types may be involved.
Where physical forces predominate the
11
-------
Principles of Adsorption
process is termed physical adsorption, where-
as chemical adsorption describes chemical
action.
Adsorption phenomena may be quantized by
considering such adsorbate-adsorbent
characteristics as gas composition, concentra-
tion and temperature, as well as absorbent
type, surface area and pore size. At present,
the primary use of the adsorption process in
radioactivity measurements is the monitoring
of releases of radioactive gases in and around
nuclear installations.
REFERENCES
1 Graham, D. Adsorption Equilibrium,
Adsorption, Dialysis, and Ion Exchange.
Chemical Engineering Progress
Symposium Series. American Institute
of Chemical Engineers. 55:24. New
York. 1959. pp 17-23.
2 Daniels, F. and Alberty, R. A. Physical
Chemistry. John Wiley & Sons, Inc.,
New York. 1955. Chapter 17, pp 522-
526.
3 Maron, S. H. and Prutton, D. F. Principles
of Physical Chemistry. The MacMillan
Company. New York. 1958. Chapter
7, pp 214-225.
4 Brey, W. S., Jr. Principles of Physical
Chemistry. Appleton-Century-Crafts,
Inc. New York. 1958. Chapter 7,
pp 244-253.
5 Stern, A. C. Air Pollution. Academic
PrE"ss. Vol. I, Chapter 11. New York.
1962. pp 418-420.
6 Stern, A. C. Air Pollution. Academic
Press. Vol. II, Chapter 33. New York.
1956. pp 367-372.
12
7 Magell, P. L., Holden, F. R.., and
Ackley, C. Air Pollution Handbook.
McGraw-Hill Book Company, Inc.,
New York. 1956. Ch. 13. P 83.
8 Air Sampling Instruments. American
Conference of Governmental Industrial
Hygienists. Chapter A-I and B-6.
Cincinnati.
9 Gresmer, G. J., Jones, R. A. , Lautensach, H.
Molecular Sieves, Adsorption, Dialysis,
and Ion Exchange. Chemical Engineering
Progress Symposium Series. American
Insitute of Chemical Engineers, 55:24.
New York. 1959. pp 45-50.
10 Codudal, M. Determination of Radon in
Uranium Mines by Sampling on Activated
Charcoal. J. Phys. Radium, Vol. 16.
1955. P 479.
11 Shleien, B. The Simultaneous Determi-
nation of Atmospheric Radon by Filter
Paper and Charcoal Adsorptive
Techniques. J. Amer. Industrial
Hygiene Association. Vol. 24. March-
April 1963. pp 180-187.
12 Sell, C. W., and Flygare, J. K., Jr.
Iodine Monitoring at the National
Reactor Testing Station. Health Physics.
Vol. 2. 1960. pp 261-268.
13 McConnon, D. Radioiodine Sampling with
Activated Charcoal Cartridges. AEC
Research and Development Report,
HW-77126. April 1963.
14 Browning, W. E. Removal of Volatile
Fission Products from Gases. Nuclear
Reactor Chemistry. First Conference,
Gatlinburg, Tennessee. Octobe r 1960.
TID-76l0.
-------
ADSORPTION
TO
SYSTEMS AND THEIR APPLICATION
AIR POLLUTION CONTROL
Don R. Ll:!e
I
ACTIVATED CHARCOAL IN AIR POLLUTION CONTROL
Adsorption deals in the realm of molecules
rather than solid materials. As such, it
should be considered wherever air contamin-
ants arc Raseous in natUrl'. An adsorbent
is " material which utiUzes the phenomen-
on of adsorption to collect, entrap, and
",>nccntrate thelOe molecules.
Activated charcoal has becoml' almost synony-
mous with adsorptIon hecause it is the most
universitl adsorbent known. It has long
h"l'n UIOl'd in Ras masks, resp I rators, atomic
s..hmar, lIll's CIIR filters, Hpace capsu]C'H,
and Wht'll'ver a man's life deppn,ls on the
rl'mov:11 or toxic Rasl'S from tl.., air.
For those who wIsh to delve int.. thl' tht'ory
..r adsorpt ion, plt'ast' reff'r to the rcfer-
l'nc!'s at the end of th is art Ie Ie.
F,'r our ,'onslJerut Ion it
kn()\{ till' following factH
r'lIOlrcoa 1 and adsorrt 1011:
Is il1lportallt to
:lbout uctlvated
I.
AI,tivatC'd charcoal and itdsorptinn is
hut onl' ml'tlwd a"'ollg many to ('] iminate
gaseous rolllltants from the air. Each
casl' has 10 1)(' considC'red individually
to determilw the b(,st method or combin-
ation of ",,,thods to lOolve thl' rrobIt'm.
A" a rul.. of thumb, hasC'd on eXlwrience,
activated charcoal arrl'an;'\'o h;IVI' an ad-
villllagl' UVl'r ntller ml'lhods wh.'n:
A.
Largl' amounts of atr have to IH'
IIti lized 10 caplure lhl' pollutant.
1\.
CllnCPl1troillons "f ('onlulliinants are
l'x(,l'rtjonally Jow, so as to make
otl"'I' III!'thuds IlIIpl'\I'II('al bul for
01\1' rl'd:.nn or [)llot!H'r 111\1';1 Ht l J]
ht, reIl1Pv(.d.
r:.
111 Idr,llI'r l'"nc('ntrat(ons whl'rl' thl'
adsorhed lIIat!'rial Il.'s ,I n'('nv('ry
va 1 \1('.
D.
Sm.111l'r applic'11ionH whl'n' SP'lC(,
and economy d ir' tatps I h(' use (1 f
.Il'liV.1ll'cl ('har('oal flJI('rs nv('r
bu lk i I' r syslI'mf.;.
'~k:n -I:: -l~~'-~': -~:'UI~S\;I~;_I;~~ -~'~)~~:~)~s=o~,~_oJ
PA, C,!}'" OJ? , 17,70
2.
Activated charcoal is not in itself a
method of disposal, but a means of
concentrating adsorbed materials so
that they, in turn, can be disposed of
or recovered. In a sense it can be
compared to a vacu~m cleaner bag which
has a definite capacity for contaminants
and once filled, must either be emptied
or replaced.
3.
There are other types of adsorbents,
such as activated silIca or activated
alumina. Most of theRl' adsorbents
are selective towards polar compo\lnds,
Ruch as water. Activated charcoal is
unique In thal it Is more selective
towards non-polar compounds, thU8 making
it porticularly suitable for 0Tl~ani c
contaminants. Activated charcoal
will adHorh water moleclllt's as well as
any other type of moiecule that comes
in contact with It, but as a rule ~i]l
be displaced hy organic molecules. Thl'
same applies lo most true galOes, such
as oxygen, nltrog~n, argon, etc.
4.
Among organic materials, activated char-
coal is more selective towards larger
molecules and those having higher boiling
points. At any given operating condition,
activated charcoal will have good car-
acity for those organic materials which
would ordinarily he liquids or solids
at that condition. As an example, at
normal room pn'ssurl' and t.'mperature,
activl1ted charcoal would hav(' a good
capaci ty for ethyl alcohol but a poor
capad ty for ethane. However, a] ter i ng
these condlt1ons by lowering th., If'mr-
E,'ratllrC' h(']ow lh(' hoi ling p"lnt of l'thilm',
till' Cxl'('ptinn:llly shorl
('ontacl tlm... Tit!!> plt"lllI,"enon <',1n 1",
ullJi7,('d 111 ('0,"h111<1tiol1 with elt"lIIlc.11
rea!' t ion hy imrn!~nil t I ng .1(' t ! va ted ell'l r-
coal wltlt v:lr(ous l1IaterLd:; to enhancl'
its' ahillty to pIck up and retain
!,~!!_<:,~,!:~y, inorgunic, ga:;('~;. For inslance,
-------
Adsurption Systems and Thcir Application to Air Pollution Control
an activated charcoal impregnated with
a suitable alkaline material can do an
excellent job of adsorbing and retaining
acid gdses, such as, sulphur dioxide,
hydrochloric acid, various oxides of
nitrogen, etc. In this case, we combine
the speed of adsorption with the slower
and more positive chemical reaction.
6.
Types of Activated Charcoal - There
are a wide variety of activated char-
coals or activated carbons (synonymous).
Some are more suitable for liquid puri-
, fication, others more suitable for de-
colorization, others for air purifi-
cation, etc.
Activated charcoals vary widely in their
pore size, pore volume, total surface
area, pore distribution, hardness, im-
purities, granular particle size, etc.
An activated charcoal highly suitable
for decolorization of sugar would, more
than likely, be completely inadequate
for air purification and vice versa.
This wide variety in activated charcoal
leads to a lot of misunderstanding -.
about selecting this material. The
selection of a proper adsorbent can
be affected by: The type of contaminant
or contaminants, their concentration
in the air-stream, operating conditions,
such as: temperature, pressure, relative
humidity, regenerative or non-regenera-
tive systems, efficiency of removal
desired, whether or not the adsorbed
materia] has a tendency to break-down
on the charcoal, and contact time re-
quired.
AOSORPTiON SYSTEMS - With the previous
fncts in mind, adsorption systems might be
broken down Into; thin bed or deep hed,
regenerative or non-regenerative systems.
'1'0 ('l.lrify terminology, "re~cnerlltion" IIHlIlIlly
indicat"s lilt' P10("'SS by which the .:Idsorbcd
<'ol1tamln.\I1ls arc removed "In place", usually
by 11 heat ,;ourCl', such as steam. "Reactiva-
t ion" liS "'I 1 I y refers to the process by which
the adsorlH'd contaminantH arc burned off
at hi/(h temperatures in special furnaces.
This process is sometimeI' done at the Job
sIte, but invariably involves the removal
of the adsorbent from the adsorbcr.
"RegeneratIon" is only used when the air-
stream is clean (devoid of particulate
mutter) and the organic contaminants are
well defined as to their nature and con-
centration. Since steam is invariably used
as the heat source, two further prerequisi tes
are required: We must be able to remove
these adsorbed organic materials at.the
temperatures of steam or super-heated steam,
and these materials must not polymerize
on the carbon at these temperatures.
"Reactivation", on the other hand, does not
have such limitations inasmuch as all or-
ganic materials break do~ at the higher
reactivation temperatures. In some extreme
cases, the reactivator must give considera-
tion to the elution of other adsorbed mat-
erials so that he, in turn, does not be-
come a source of pollution himself. This
could apply in the case of adsorption of
various acid gases, sulphur dioxide, halo-
gens, poisonous metallic compounds, and
radio active materials.
If the concentration of a contaminant in
the air is low enough and the capacity of
activated charcoal for this contaminant
large enough, expertsive regeneration systems
are not necessary. If the activated char-
coal is used at a rate which would necessi-
tate replacement every two or three days,
the chances are a regenerative system would
be desirable, if feasible. There are many
cases where the charcoal is replaced as
often as every week and it is still less
bothersome and expensive than trying to in-
stall a regenerative system.
There are many applications where activated
charcoal filters as thin as. 1/2 inch to 2
inches give excellent results in both effic-
iency and longevity.
SOLVENT RECOVERY SYSTEMS - To date, most of
these systems have been installed by industry
to recover valuable solvents for re-use.
whIch would otherwise be lost. As such,
most of these systems pay for themselves
In 11 short period of time. For this reason,
they have heen referred to as "solvent
vapor recovery systems."
At present, hecause of air pollution problems,
consIderation must be given to these systems,
even though there's no economic gain to be
achieved by recovery. In some cases, the
recovered solvent can be re-diluted into
an air-stream in suitable concentration
for combustion or incineration, prior to
exhausting. Also, it may be feasible to use
the solvent as a fuel or utilize it in some
other process.
The' following is a list of "those air puri-
fication applications where non-regenerative,
inexpensive, thin-bed adsorbers can be used.
-------
*l\ciJ Cases
I\ir Cunditiuning Systems
Allergy Patients (I\ir Purif.)
*Ammonia
*I\mine Odors
I\nim;1I Shelters
Apple S~oragc
1\ rc h i V~' s
Art Galleries
I\tomic Power Plants
ATomic Suhmarlnes
i)uditoriums
I\utomobile Exhaust Fumes (organic)
Bacteria Removal
Brine Solution Odors
IllIrn Pati{'nts (Air Purif.)
*C;lrhon Diuxide
Cancer Patients (Air Pur if.)
ellH Filters
Cht'mical l'lants
Ch loramim' (odor)
'\Chlorin~' (odor)
Chromat{' Baths
Churches
C i~an~t te odor
Clean Rooms
Commun i ty De fense Shel ten'
Computor Rooms
Con f ,'rCI1!'t' Rooms
*Corrnsivt' CaSC8
Cralll' C..hs
D i t' thallo I amine (lW.A)
Display Cast's (tarnishing)
Dry C I ('WI i ng Shops
~It'ttrital Controls
1':lIIh,.11II i IlK I{oums
,.:thv\('llt' (o['l'hid growing)
":xpo,; j t j Oil lIa 11:;
'\I'Clhrit':, (l't'rmall"llt I'r<',,:;)
I'",'n i I iZt'r I'lant,;
I," "WI'I" SIII'"s
Fond 1~1-~)l.PSS t ng
Fon..1 ~~ l () ra)',l'
,"1.'''1 ""1 1.I<'hyd,'
1'1I11<'r.1I 110'""'"
(:.lrh..~(. Sf pr~l~l'
*1:,,,, M,I';!.,;
Ca>-;o I i lit' F"m,'"
(;n.',,'nhou~es
Cy",anasillm~
'\lIa I ogen:;
11 i gh R 1St' Apa rtmen ts
lIomes
Ilospi ta Is
lIot e 1 Hooms
*lIytlrogt'n Cyanide
*llytlruKt'n Sulfide
III<' i IH' ra to rs
Infirlllerjes
Adsorption Systems and Their Application to Air Pollution (ontrol
TABLE I
Instruments (Air Purif.)
Jet Aircraft Terminals
Jet Airplane Cabins
Jet Airport Field Busses
Jewelry Stores (tarnishing)
Kitchen Range Hoods
Laboratories
Laboratory Fume Hoods
l~aundries
l;~ad.i Tetraethyl
Locker Rooms
Mercaptans
*Mercury Vapors
*Hetal Pickling
Mildew Odors
Mold Odors
Honethanolamine (MEA)
Morgues
Moving Vans
Museums
*Nitrogen Oxides
Nursing Homes
Nurseries
Office Buildings
Ozone
*J>acivation Tanks
Pharmaceutical Odors
Photographic Dark Rooms
Pickle Mfg. (brine odors)
Pizza Ovens
Plastic Mfg.
Pulp & Paper Mills (Electronic Control)
Active Gases (Hot Cells)
Range !loods
REfrigerators (Domestic)
REfrigerators (Cornmerical)
Refrig~rator Cars
Rendering Odors
He.dn Cooking (!lot Melt)
R~spiratory Patients (Air Purif.)
Respir:Hors
Rt'st Rooms
I{estaurants
I{ubber Mfg.
Schoo] s
Scuba Divin~ (Compresscd I\ir)
Septic TAnk Trucks (Vents)
Sewage Treatment Plants
Sewer Vents
Sick Rooms
Smog Irritants (Gases)
Solvents' (Low Concentrations)
Space Capsules
Stadiums (Enclosed)
*Steel Plants
Submarines
*Sulphur Dioxide
Theaters
Toxic Gases
(continued nex~ page)
3
-------
TABLE 1 (Cont.)
Underground Parking Areas
Underwater Experimental Stns.
Uni ve rs it ies
Veterinary Clinics
* May require impregnated charcoals
The most common types. of regenerative systems
are utilized in handling high concentrations
oj solvents or solvent-like vapors. The
followIng is a list of applications that
II.~vc lent themselves to this type of system.
TABLE II
"~'L' lone
Adhesive Solvents
Amyl Acelate
f\cnzene
Iknzol
Ilrom-Chior Methane (BCM)
lilltyl Act'tate
BlItyl Alcohol
Carbon Bisulf ide
Carbon Dioxide (Controlled
Carbon Tet rachloride
Coating Operations
Degreasing Solvents
D[ethy] Ether
Dist i I icries
Dry Cleaning Solvents
Drying Ovens
[',I hy [ Acetate
I'lhyJ Alcohol
Et IIY lene Dichloride
lI.lbde Coaters
Fi 1m Cleaning
Fluoro l1ydrocaroons
I,'n'ons (some)
I'u(' I () i I
C;f th,' fo] lowing:
(See Diagram 1)
II.
IIctivated charcoal adsorber: With an
inlet and outlet, a steam inlet and
an outlet to exhaust the solvent vapor-
steam mixture. and suitahle valves to
Virus Removal
Warehouses
Waste Gases
Whiskey Warehouses
Jlydrocarbons-Aliphatic
Hydrocarbons-Aromatic
Isopropyl Alcohol
Isotrons (some)
Ketones
Methyl Alcohol
Methyl Chloroform
Methyl Ethyl Ketone (MEK)
Metbylene Chloride
Mineral Spirits
Mixed Solvents
Monochloro Benzene
Naphthas
Paint Manufacturing
Paint Storage (Vents)
Pectin Extraction
Perchlorethy1ene
Pharmaceutical Encapsulation
Plastic Manufacturing
Rayon Fiber Manufacturing
Rotogravure Printing
Smokeless Powder Installations
Soya Bean Oil Extraction
Stoddard Solvent
Tetrahydrofuran (THF)
Toluene
Toluol
1.1,1, Trich10rethane
Trichloroethylene
Varnish Storage (Vents)
Xylene
Xylol
control the intermittent steam and
air-flow.
IL
Steam or heat source: The flow of
steam is counter-current to the
orginal air-flow.
C.
Condenser: To cool and liquify the
stripped solvent vapor and steam mi~
ture.
-------
A<.Isorptioli Systems and Their Application to Air Pollution Control
DIAGRAM I
CLEAN
DRY AIR
SOlVENT
LADEN
AIR
QC
W
~
....
A
PU IFIED AIR
B
SOLVENT TO
S10RAGE
STEAM
WATER 10 DRAIN
OR REUSE
Adsurption-Desorption Cycle
Adsorption
ValveH land 2 are open. Valvei:l 3, 4 and 5 are
cloHed. Air containinK vapor is pai:lse(! through
"I''' pre-filtration system for removal of solid
partic!t'H, then through activated charcoal bed
"A" for adHorption of the solvent vapors. The
purified air is then exhausted or returned for
l-e-lise.
Desorpti on
After the activated charcoal has become saturated,
Valves land 2 arc closed and Valves 3 and 4 are
opened. Steam from boiler U heats the activated
charcoal h"d and Htrips the solvent vapor. The
solvent vapor-steam mixture is passed through
CondcnHer e. The condensate then drains into the
dl'eanter "1>" for separation (immiscible ,;olvent).
~
V;11 VI'S I, I and 4 arc c I oSl'd and Va 1 ves 2 and 5
.IT<' ol"'n,,d. ell'all, dry air i1:> passed uv.'r till'
aetlv.ltl'd charcoal hed to remove exc"S1:> moisture.
Entin' ('y('I,' j,; th('n rl'peated.
n.
11('(';lIlt.'r (lr I>lst Illallon system: II
th" solv('nl Is 1IIIIIIIs('ll1ll' with w;lt"r,
II,.. ,"''',rati"n of Ihe ('()I1,l<-ns.lll' ('IHI
I", sllll"I,' hy th., liSP "f .. d,'cant.'T. In
mw;t cas.'s tldH Is slifflel,'nt to ohtaln
.1 purl' )'(\-u~1ah 1l' so 1 v('nL. In :->0111(' ('ase~,
It lIIay h(' \1('ce,;slIry to further purify
the solvent or tlu' wL'lIk water solution
hefon' UHe or diHpoHaJ. If the '~o]'!('nt
i" mLseLhll' with resp('ct to the water,
dlstillatlon may he requl red for
sep;lrat j nn.
5
-------
The suI vent vapor recovery system will also
require equipment for purifying (removal of
particulate matter) and moving the contaminated
air through the bed of charcoal; a blower and
a source of clean, dry air for cooling and
drying the activated charcoal after the steam-
ing cycle; valves and other control equipment
for diverting the air and vapors in carrying
out the various adsorption-desorption cycles.
Additional equipment may be required to bring
the air, to be treated, to a suitable condition.
For instance, air coming off of drying ovens
will have to be cooled. Air coming off of
se rubbe rs may have to be treated with de-
mIsters or even raised slightly in tempera-
tur!> to lower the relative humidity below 100%.
Air containi"g high bollen;, such as oil vapor,
may have to be passed through an activated
charcoal protector bed. Since all particulate
matter is harmful to a regenerative system,
high l'ffidency particulate fi 1tration may be
required, as in the case of a spray paint op-
eration.
COST OF REGENERATIVE SYSTEMS
The tollowing table may be used for approxi-
mate pricing'of solvent recovery systems:
Since some solvents have a tendency to break
down into highly corrosive substances, due
consideration must be given to the materials
of construction of the system. Impurtties
in the system and the activated charcoal may
catalyze the breakdown. The temperature and
pressure conditions during the desorption
cycle can also be critical.
As in the case of the handling of any flammable
mixture, due consideration must be given to
the lower explosive limit and the use of ex-
plosion proof electrical equipment and wiring.
In cases where the LEL is somewhat critical,
special care must be given to the heat develop-
ed during the adsorption cycle (heat of adsorp-
tion) and assurance that the bed is cooled
properly following the desorption and cirying
cycle.
The solvent vapor recovery system shown in
Diagram I must have a shut-down during the
adsorption cycle to carry out the regenera-
tion process. Addition of more adsorbers with
a pre-determined cycle can eliminate shut-down
and will lend itself to automatic controls.
The following example will describe such a
system.
-- ------- - - -- -- ---- --- - ----
-----------,
Table 3. INSTI\LLED Et~UIPMl~NT COST PEH. SCFM
S(,I,'I\;1 Sol \1 'III l:Unn'II1.I'ation (GPH pcr 1000 SCFM)
1\ 11'- ",II t.
lhnHlgh syskm o.O~ I 'J C 5 10 20
,". ,)
-
I. 000 $ 1:1.00 $14.0() $1Ii.00 $1!J.00 $2 L 00 $22.00
:~. 000 !). 0 I) 10.00 10.00 12.50 16.00 19.50
---
-I, (10(1 Ii . ()O 7. 7:i II. 7;, IO.O!) Il.00 17.50
----
II,O()O ,... ')r li.:.!!i 7. ~;) fI.45 )(J.25 15. 50
,). ....)
_.
1;',0(1(1 :). D;) .1. :i5 4.7;) 7.0!i 1).00 l:i.OO
30.000 .1. I;) :!. 4() 4.:.!5 Ii. (i 5 8.40 11. :i5
(jO, (I()() 'J 'Ir: 2.GO :L 75 (i.25 8.20
I.J. d.)
100,00(1 ~. 15 2.20 :1.:W li.OO 8.00
1 ;)0, 000 J.!J5 2.00
- ---_.-
<>
--- ~--------- - .--. ----------
-------
These prices are for the solvent recovery
syscem only including adsorbers, cycling
valves and controls, charcoal beds, condenser,
decanter (if needed), blower(s) and motur(s)
of standard construction, interconnecting
ductwork-piping and sewers, all installed
with necessary foundation on ground level.
It is assumed that a cleared level site is
available - ductwork, piping and sewers lead-
ing to and from the system, insulation of
equipment, not included.
B
Corrosion resisting materials: Type 304
Stainless Steel - 20 tu 25%; for other
materials, extras will vary.
C
Particulate pre-filter, ai.rcuoler, chemical
scrubber according to Dced.
D
Distillation equipment <13 Il.ceded.
ACTUAL ADSORPTION SYSTEM
A
Explosion proof electrical equipment &
. wiring - 10%.
A photograph and process flow diagram for
an activated charcoal adsorption-regenerative
system is shown in Figure 1. Other applications
of adsorption-regenerative systems are shown
in Figures 2 and 3.
Add for additional costs (it needed):
Scrubbmr;
Ilqutd '.
810w~r
To
oll1>Osph~r~
Figure 1. A UTOMA TIC RECOVERY SYSTEM FOR
ISOPROPYL ALCOHOL FROM A CITRUS FRUIT
PROCESSING PLANT
7
-------
t
I
i
i,
i.
. !
. ~. ) 1
i
~.
/ \\.,
--
. .
.:: ~,' :,'" . .. '.
,":.:.,~ .
Figure 2. AUTOMATIC RECOVERY SYSTEM FOR METHYL CHLOROFORM
. FROM ULTRASONIC FILM CLEANEHS IN A MOVIE FILM PROCESSING PLANT
Figure 3. SEMI-CONTINUOUS H F:COVERY SYSTEM TO RECOVER
ETHYL ALCOHOL VAPO]{S F}{OM A WHISKEY WAREHOUSE
B
-------
Secfion Ten
LIQUID WASTES
Liquid Industrial Wastes
Wastewater Reduction
-------
~
Reprinted with permission from Industrial Water and Wastes Magazine.
Liquid Industrial Wastes
SIN' E TilE PASSAGE by Congress, in
194H, of Public L,w 845 (the Water
l'ol1uti"u Control Act of 1(48), in-
dustries and nlllllicipalities alike have
t:tk,'u a more active part in the pro-
tect iOIl of natural streams from pollu-
tiot\. I'rior to 1<)..8, many public-
spirited industrial conCt'rns had in-
,tailed sl ream prolection works, often
at considerahle t'Xlwnse: hut since the
passing of this first Federal legislation,
ahno,1 all companies have been made
a wa re of the seriousness of the water
problem.
Next to air itself, water is probably
the most vital material to mankind.
Plentiful, clean water is essential, not
only for the individual's existence,
health, and comfort, but also for civili-
zation's cities, agriculture, commerce,
and industr~'. Polluted water, con-
taminated with the refuse of munici-
palities and factories, may he totally
without value for certain of these fun-
damental applications, and is r('dnced
III value for all purpose's.
Sources of Pollution
This Sf'rirs of articles is concerned
by C. FRED GURNHAI.1,
primarily with the wastes discharged
by industry, \Ve must take notice.
however, of other sources of stream
pollution, because each type of con-
tamination afTects and is affected by
all others. \Ve have learned only re-
cently, for example, that phenolic com-
pounds, a highly objectionable pollu-
tant in streams and a pollutant that
is generally ascrihed to industrial
wastes, may he formed in troublesome
concentrations hy the normal decay of
natural vegetable matter.
Natural Pollution
Pollution resulting from natural
causes may have a pronounced effect
on stream water quality. Little can
he done to abate this source of pol-
lution, but it is important that we at
least recognize it. Among the objec-
tionable characteristics that may orig-i-
nate from natur;t1 causes are: color.
taste (phenolic or other), dissolved
minerals aud salts, organic matter,
suspended solids, and turbidity.
Pollution from Agriculture
Agricultural practices and civil en-
gineering works often have a strongly
deleterious effect on stream quality.
The cultivation of land surfaces
changes the water runo/I character-
istics, not only in volume hut in chemi-
cal composition as wel!. Improved
methods of agriculture, including con-
tour plowing, have done much to re-
duce stream contamination from this
source. The widespread use of fer-
tilizers, insecticides, weed killers. and
other agricultural chemicals has led
to serious stream pollution. including
extensive fish killings, on a numher
of occasions. This pollution rnust be
attributed to agriculture; however,
because chemical products are in-
volved, the chemical manufacturing
industry is engaged in active research
to find means of relieving the situa-
tion. Highways and other civil engi-
neering public works change the
drainage characteristics of their areas,
aud introduce pollutants such as as-
phaltic compounds, oils, and gasoline.
Mining Pollution
Suspended solids and turbiditv are
caused in stream waters as a result
of mining- operations. Much of this
P A. PE. 2. 1. 68
-------
4
AT MANY MINES, present-day practice provides large settling basins or
lagoons for the removal of settleable solids before they reach a natural
water course.
pollution originates from dumps of
tailings and other waste solids. Pres-
ent-day practice. in effect at many
mines, provides large settling basins
or lagoons for the removal of settJe-
ilble solids before they reach any nat-
ural stream.
Dissolved salts, sometimes of a
toxic nature, are a1so formed from
mining operations. During the actual
mining. and in subsequent crushing
steps, fresh surfaces of ore material
are formed. The surface atoms of
the crystals are in an active state. and
meta1lic elements are readily leached
from the rock into surface streams or
ground water. J n this manner, such
toxic substances as salts of copper,
zinc, lead, and other metals are formed
and introduced to the watercourse.
In the production of crude petro-
leum at the oil fields, two serious
stream pollutants are formed. The ob-
vious pollutant, oily matter, is a loss
to the producer; hence every possible
effort is made to reduce the quantity
escaping, by careful handling and by
installation of oil separators in the
effluent channels. Even a trace quan-
tity of oily p01lutant can have a major
effect on streams, because of its in..
soluble nat ure and tendency to form
surface films.
A second p01lutant, brine, is pro-
duced at most oil wells, and its dis..
posal poses a major problem to the
industry. Although sma1l amounts of
salt are harmless in streams, the quan-
tities produced fit many oil fields can-
not be tolerated. There is no known
method of treating brine wastes for
disposal, except at exorbitant cost;
hence many oil producers re-inject the
brines into the underground forma-
tion, or store them for discharge at
times of high stream flow.
Mun:cipal Pollution
Over the United States as a whole,
municipalities and industries are ap-
proximately equal in the total volume
and the organic concentration of
waste discharged. The ratios vary
greatly, however, from one region to
;\Ilother.
Municipal wastes consist of: (a)
domestic sewage and household wastes
(sometimes including ground gar-
bilge), (b) industri;J.1 wastes that have
been discharged into the municipal
sewerage system, (c) snrfa.ce run-off
or storm water, and (d) groundwater
that infiltrates the sewers at leaking
joints or other openings. The last
tWf) items are not serious sources of
pollution illthou~h thev mdY be impor-
tant for other reasons; the third item,
storm water, is often collected in a
separate drainage system to keep it
separate from the po1luting wastes
thilt require treatment before dis-
charge to a streillT1.
Industrial Wastes
Liql1ieJ \\'astp ~lreams originate in
alJ of the prucess industries, and many
of these arc ciluses of sf'rious stream
pollution (Table 1). Certain types of
industrial wastf', particulctr1y wastes
from the fl)orl and other organic proc-
essing industries, resemble sewage in
their composition (although they may
be JI1uch n lOre ('oncentr::tted than sew-
age). These waste can often be dis-
charged into municipal sewers for
joint treatment by the municipality.
Other wastes are quite different
from sewage, and may have a detri-
mental effect on sewage treatment op-
erations. Acid wastes from steel pick-
ling, metal salts and cyanides from
electroplating, and dye wastes from
textile finishing are in this category,
together with many other industrial
wastes. These must be discharged
with care, frequently only after elabo-
rate pretreatment at the factory where
they are produced.
The detrimental effects of industrial
wastes in both natural stream and city
sewers, and methods for the control
of such wastes will be discussed in
this series of articles. Industry is only
one of the five sources of pollution
listed above, but the high concentra-
tion and often unique composition of
its wastes make them a real problem.
Solid and Gaseous Wastes
In addition to the liquid wastes dis-
cussed here, industry produces wastes
in solid and gaseous forms. These
materials may give rise to disposal
problems as serious as the liquid efflu-
ents.
Solid wastes have the obvious prop-
erty that they remain, at east for an
appreciable time interval, in the spot
where they are placed. Their disposal
Table 1
Typical Industries That May Cause
Pollution
A.
Food Industries:
Breweries and distilleries.
Canners.
Corn product manufacturers.
Dairies.
Meat packers.
Sugar refineries (beet and cane) .
Mineral Industries:
Coal miners and processors.
Coke and gas producers.
I ran and steel mills.
Non-ferrous metal producers.
Oil-producing fields.
Petroleum refiners.
Process Industries:
Chemical manufacturers.
Electroplaters.
Pulp and paper mills.
Soap and detergent producers.
Tanners.
T exti Ie processors.
Miscellaneous Industries:
Atomic energy plants.
Automobile manufacturers.
Electrical product manufacturers.
Power plants.
Railroads and airlines.
Water treatment plants.
B.
c.
D.
-------
[)
is, therefore, largely a matter of trans-
portation to a suitable area of waste
land, for dumping. Care should be
taken, however, that they do not
escape from the dump area into neigh-
boring natural waters. .Soluble con-
stituents may be leached out by rain- I
fall or ground water, and small par-
ticles of solid are carried away by sur- I
face waters. Under no circumstances
should solids dumps be located di-
rectly on stream banks, as this would
make pollution both inevitable and ex-
cessive.
Solid wastes are occasionally trans-
ported from the manufacturing area
to the dump by means of a liquid
stream. This is a common practice for
waste sludges, such as are produced
in water softening. acetylene manu-
facture, and other chemical industries.
Water transport may also be used for
cannery and beet-sugar wastes and
solids of similar nature. In water-
transport operations, it is essential to
provide adequate screens or settling
lagoons to retain the solids and to per-
mit the clarified water to flow to a
stream.
Gaseous wastes and dusts are pro-
duced in many industries, and may be
a nuisance or even a health hazard
unless they are adequately controlled.
Ventilation equipment such as ex-
haust fans and hoods are commonly
employed to protect the plant workers
from toxic or nuisance gases, vapors,
sprays, and dusts. If the vented air
is discha~ged without treatment, it is
a contributor to atmospheric pollu-
tion, and may be highly objectionable.
This subject cannot be discussed in
the present series of articles for lack
of space. One means of abating at- uses.
mospheric pollution is to wash the
contaminated air before discharge;
this produces a water effluent that may
require treatment before it is released
to the sewer or watercourse.
Effects of Wastes on Streams
It is not only inevitable that most
liquid effluents from cities and indus-
tries ultimately reach natural waters,
but it is perfectly reasonable and
proper that they shoud do so. The
situation becomes unreasonable only
when the nature and concentration of
the wastes i$ such that the stream be-
comes polluted. All streams carry
some quantity of contamination-none
is pure "distilled" water-and a slight
degree of contamination by silt or
salts or organic matter is in no way
objectionable H cavier contamination
by the~e or other substances. particu-
larly by poisonous "chemica!" sub-
stances, causes polJution, and this con-
dition is objectionable.
The exact poin~ at vl/hich stream
quality changes from "permissib1e" to
"objectionable" is subject to many in-
terpretations: there is no question as
to the harmful nature of gross po!1u-
tion, but lesser degrees of polJution
may still be undesirable or even in-
toleranc~ for many desired stream
Public Welfare
The primary consideration in deter-
mining permissib1e concentrations of
polJutants in natural waters must 1:Ie
public heaJth ;lf1d public: safety. This
is not to say tha: aU streams should
be considered "lik",--waters used tor
public water suppi.y must obvious1y be
of higher quality than streams used
for canoeing and boating, and stre:1.ms
used only for navigation and waste
transport may be far inferior. The
safety factors should be decided in
view of the pre3ent and future "best"
uses of the particular water; the fac-
tors will vary from one region to an-
other, even in the same watershed.
The public health factor depends
largely on the presence and concen-
tration of pathogenic organisms.
These result chiefly from ~he dis-
charge of raw or insufficiently treated
sewage. and do not ordinarily origi-
nate from indust~ial wastes. An occa-
sional exception may exist in wastes
from tanneries and perhaps meat
packers, but these are not usual.
A second effect on public safety
arises from toxic industrial wastes.
Dangerously high concentrations of
cyanides, metals, insecticides, and
other poisons cannot be tolerated in
water that may be used for drinking
water-not even if the water is treated
before use--hecause conventional wa-
ter treatment is not designed to re-
move such impurities. Possible pol-
lution of drinking water supplies must
be considered for wastes that are dis-
charged onto the land or into under-
ground disposal wells as well as for
wastes that enter surface streams.
Cenain toxic materiaJs, such as
metal ions, may be absorbed by fish
or shellfish living in slightly poJluted
waters. If these animals are later used
for human food, there is some danger
to health from the poisonous sub-
stances.
Aquatic Life
Industrial waste discharges are of-
ten responsible for the destruction of
-------
6
NO
i SWIMMING
.~.~ \ PQl.LUTED WATER I
~
fish and other aquatic life, or of land
animals and birds that drink from the
polluted stream. Contrary to a popu-
Jar belief, most animals are not kept
away h-orn polluted streams by any in-
stinct-too often valuable farm ani-
ma]s are killed hy cyanides or other
poisons. Fish and aquatic life, of
course, ha've no means of escape: and
sudden -discharges of trade Wi1ste have
been known to destroy litera]ly thou-
sands of valuable fish. The fault is not
always with industry, however; ]arge-
scale fish kills have been known to
OCCllr irom uatural causes (a1though
industry generally received the popu-
Jar blame).
Economic Damage
Excessive quantities of industria]
waste in natural waters cause defin:te
economic damage in many different
ways. Acidity from the dischar!?;e oj
free acids and certain types of salt ha,~
been known to corrode concrete and
meta] structures, including outfall
works, bridge piers, docks, and ship
bottoms. Heavy loads of settleable
solids result in the fining of reser-
voirs and the formation of sludge
banks in streams. The latter may be-
come so large as to interfere with
navigation. This type of pollution is
more commonly caused bv nature or
agriculture than by industry, but it
has resulted from coal-processing
values and causes
plants, sand and grave] washeries,
and other mineral industries.
Economic ]055 also results when
water polluted streams must be puri-
fied for municipal or industria] use.
The cost of water tr('atment may be
greatly increased when industrial
wastes are present. Some contami-
nants can be removed by statidard
treatment methods. hut they impose
an add en Imrd(,l1 on the fi1cilities.
Other in'fH1rities necessitate over-
doses of tre;>tmC'llt chemic:\ls. such as
coagulants or chlorine. for their re-
moval. Some rnrticubr impurities
may even r('quire novel methods of
treatillent, such :\s react;on with ozone
to destroy p1lE'llolic waste".
A less tan~ihle form of economic
damage. whic:l ie, nevertlwless rea],
arises from prnnertv denreciation and
Joss \)f recre~,tJ(1n'll ;l1ld est!wtic val-
ues. The ['-re',,"11('<' Of \'i ,ihle or odor-
ous or mhen\'ise nc)',i"us wastes in a
stre:lm rendt'r~ thl' \\':lters and their
environs u"suitahl<, for Ilnny pur-
poses Land values are accordingly
depreciated, and people must travel
f;1rther for their fishing. swimming.
and picnicking.
Effects of Wastes in Sewers
The discharge of industrial wastes
intn municipal sewerage svstems can
certainly be tolerated in greater con-
centration th;1n simibr discharge into
't.
natural streams. Uncontrolled dump-
ing, however, is not at all permissible,
and there are definite limitations on
the concentrations of many industrial
waste constituents.
The quantity of industria] waste
that can be tolerated in a municipal
sewer is obviously dependent of the
nature of the waste, but it depends
also to.a considerable degree on the
type of sewage treatment. Some sew-
ers serve only to collect the sewage
and waste for discharge without treat-
ment into a stream. In these sewers,
the !imitation on any specific indus-
trial waste component is practically
the same as the stream standard, The
domestic sewage provides dilution, but
does not change the total quantity,
Most municipal sewers, however,
lead to some kind of treatment plant.
At this point, the industria] waste may
be partially removed, together with
the sanitary waste. The extent of this
removal may be large or small, de-
pending on several ractors. A]most
all treatment plants employ at least
primary sedimentation, which serves
to remove much of the settleable
solids, of either domestic or industrial
origin. In addition to primary treat-
ment, many plants provide secondary
treatment of the settled waste, gen-
erally by biological oxidation. This
step furnishes a substantia] decrease
in the organic content of the waste,
whether dissolved or suspended.
The reduction of industria] waste
concentration by passage through a
sewage treatment plant is desirable.
but it is an added load on the plant.
Excessive quantities of industria]
waste may overload the system unless
adequately provided for in the origi-
nal design. Excessive volumes result
in shortened times for retention in
settE:1g basins, in chlorine contact
tanks, and in other units, and so may
lead to less effective treatment. Ex-
cessive organic loadings may consume
more oxygen than the secondary treat-
ment facilities can supply efficient]y,
also causing less thorough purifica-
tion of the waste. Chemica] require-
ments for sewage treatment are in-
creased by many kinds of industrial
waste; this is particularly true of
chlorine used for disinfection, but ap-
plied also to coagulants, pH adjust-
ment chemicals, sludge conditioners.
and other materials that must be pur-
chased.
The principal objection to indus-
.".
-------
7
I
I MUNICIPAL sewage treatment plants at the end of sewer systems may handle some types of industrial wastes satisfac-
I torily, but othe: ~ste.:...may cause trobble or incr.:ase treatment loads and- cos~.
trial wastes in sewers, however, is
not based on lhe added load they im-
pose. Instead, 111any industrial prod-
ucts have a detrimental effect on the
sewage treatment plant, and interfere
with purification of the sewage itself.
Important among these constituents
are chemical salts, especially the
heavy metals like copper and zinc,
and cyanides. These alld other com-
ponents of the waste are toxic to the
biological organisms that perform the
destruction of organjc sewage matter;
hence the process efficiency is im-
paired or t\'eH stopped.
Public safety must be considered in
the discharge of flammable wastes.
Gasoline and other petroleum prod-
ucts, and watf'r-immiscible organic
solvents, may introduce the hazard of
fire and explosion. This danger is,
of course, greatest in confined spaces,
and is a major problem in sewers.
The discharge of stich substances in-
to sewers is usually prohibited by
tnttnicipaJ ordir:ance foe this exceIknt
reason.
Legislation
Legislation rdating to the dIscharge
of industrial wastes is of two major
types: that relating to the protection
of natural waterways (usually on a
national or state-wide basis), and that
designed to protect local sewer sys-
tems and sewage treatment plants.
Significant Federal legislation has
existed only since 1948. Public Law
845, of that year, authorized the
United States Public Health Service
to take an active interest in stream
pollution. These studies include the
effects of industrial wastes as wel1 as
other sources of contamination. The
legislation was extended and put into
permaneut form during 1956 (Public
Law 660 of the 84th Congress).
The principal control of stream
quality is in tl,e hinds of the several
states. Except for the problem of
interstate waters, this is entirely
proper. Quality requirements of nat-
ural waters vary greatly from one
part of the c:ounlry to another, and
any attempt at t!ldormity imposed on
a nationwide basis would be ridicu-
lous. Some ~tales of course, have
been more progressive than others in
preserving their natural resources, but
each state acts to meet the needs of
its citizens. Str-caills that C[oss state
boundaries or that are adjacent to two
states pose certain problems. These
have been successfulJ\' halldl~d by in-
terstate a~el1cies or (,ther cooperative
agreemems beLvr:en ,;tates; if needed,
the fedela! govtP1illem can inter'lcne
to proto .,:t olJe stat\' fJ (im the pollution
of 3.tlr,t}wr.
Local O,,'i'iJ.IIU'S ,he direcled pri-
m2fily at the pl'l1Le; t;(Jn of nlllI:icipal
property, such as the sewer system
and the sewage treatment plant. The
discharge of indUSf.ri;d wasles that are
destructive to these facilities is usu-
ally prohibited. 'rhis restriction ap-
plies to flammable wastes, corrosive
acids and salts, coarse and heavy
solids, and other constituents. The
sewage treatment process, as well as
the physical facilities, also need pro-
tection, and toxic wastes should be
banned except in such dilutions as
are harmless. Finally, since the mu-
nicipality is responsible for the qual-
ity of its effluent as discharged to
waters of the state, any industrial
waste that would affect this quality
may be prohibited. This includes
metals and other toxic substances that
affect the treatment process; it also
includes materials that pass un-
changed through the treatment plant
"Ind hecome poJlutants in the stream,
such as unusual concentrations of salt,
detergents, 'or radioactive elements.
A different type of local legislation
is that directed at financial compen-
sation for use of the sewers. Many
municipalities impose a sewer charge
as a direct ratio 011 the water bill;
with an adjustment for water re-
ceived from other sources such as
private weJls, or for wastes discharged
elsewhere than the sewer. Added
charges may be levied for industrial
wastes that cause an extra burden on
the treatment plant, such as wastes
containing high suspended solids, or-
ganic content, or chlorine demand.
These properties can be related to
the cost of sewage treatment, and
formulas for establishing equitable
charges can be derived,
Measurements and Criteria
It has been said that we cannot un-
derstand a subject unless we can
measure it. This is true of stream
pollution. If we can successfully meas-
ure pollution, we can distinguish
lightly polluted streams from those
that are heavily contaminated and
-------
8
we can judge whether conditions are
improving or becoming worse. Of
course, our senses provide this infor-
mation in a most pronounced manner
if the stream is grossly polluted. It
is highly desirable, however, to have
more sensitive tests for pollution con-
trol purposes.
It was mentioned in Part I of this
series. that even sewage can be "pol-
luted" by industrial wastes. Wastes
from industrial sources may cause un-
desirahle effects in the sewage collec-
tion system or they may cause process
diffirulties at the treatment plant.
Some industrial wastes cause no trou.
ble in the sewerage system but pass
unchanged to the stream; if such
wastes are undesirable in the stream,
they should never have been admitted
to the sewer. In general, the criteria
of pollution described below apply to
industrial wastes in sewers as well as
to all wastes in streams, although tol-
erance limits for the two may be quite
different.
I t is convenient to classify pollution
criteria into three groups: physical,
chemical, and biological (Table 2).
Physical abnormalities such as high
concentrations of suspended solids can
usually be corrected by simple physi-
cal treatment such as settling. Chemi-
cal and biological pollution, however,
Table 2
Criteria of Pollution
Physical Criteria
Volume.
Temperature.
Residue on ev.poration.
Fixed residue; volatile residue.
Suspended .nd dissolved matter.
Turbidity.
Settle.ble matter.
COIIr&e and floating solids.
Oils (free and emulsified).
Chemical Criteria
Color.
Taste and odor.
pH, acidity, .nd alkalinity.
Frothing agents.
Radioactivity
Chlorides.
Other dissolved substances.
8iological Criteria
Dissolved oxygen.
Blochemlc.1 oxygen demand.
Other owygen-consumed tests.
Toxicity.
Fish and larger anlmall.
Plant life ( Irrigation) .
Microorganisms.
usually necessitate more expensive
types of treatment, often including the
addition of chemicals.
Volume
A waste characteristic of major im-
portance in disposal is total waste
quantity or volume. In any waste
treatment, the final step is dilution by
the receiving stream. Obviously the
dilution ratio provided by a stream
becomes less as the waste volume in-
creases. This applies equally to dilu-
tion by sewage if the industrial waste
is discharged to a municipal sewer.
Knowledge of the flow rate of an in-
dustrial waste is, therefore, fully as
important as information on the com-
position and concentration of the
waste.
Waste volume or flow rate is im-
p,)rtant also in the waste treatmen~
plant. Processes like sedimentation
require a certain minimum time for
effective results. In order to provide
this time, larger and more expensive
equipment is necessary for high-vol-
ume wastes, and the cost or space
requirements may be excessive. In
waste treatment operations that in-
volve chemical treatment, the quantity
of chemical reagents required is af-
fected by the volume as well as by
the quantity of pollutant contained in
the waste.
Physical Criteria
Natural waters, whether of surface
or underground origin, must possess
certain physical properties to be con-
sidered pure and uncontaminated.
Typical of these desirable properties
are: moderate temperature, high clar-
ity. absence of color, low dissolved
solids, and "normal" density, viscosity,
surface tension, and similar character-
istics. Any marked deviation from
the~ specifications is cflnsidered as
pollution.
Ttmptralure-Abnormally hot wa-
ters. such as condenser water from a
power plant, are considered to be pol-
luted. The heat may be dissipated
rapidly by loss to the atmosphere or
by dilution but, while the high tem-
perature exists, the water is polluted.
If the temperature is extreme or the
volume large, sllch wastes should not
be discharged to natural streams or
municipal sewers. High-temperature
wastes occllr commonly from the tex-
tile, laundry, paper and pulp, coke,
and chemical industries, as wet! as
from power plants.
The most apparent effect of high
temperature wastes in natural
streams is the killing of fish and other
stream life. This may occur because
of decreased oxygen solubility in hot
water. Warm streams are apt to de-
velop nusiance conditions from un-
desirable chemical and biological reo
actions. In sewers. hot wastes accel-
erate corrosion, and cause more rapid
decomposition of organic matter.
leading to development of septic cOn-
ditions. At the waste treatment plant.
hot wastes interfere with settling op-
erations and other processes.
Residues-Many types of "residue"
determinations are made on industrial
waStes, each with its specific purpose.
The "residue on evaporation" includes
nonvolatile constitutents of the waste
determined under arbitrary but well
defined conditions. The waste sample
is evaporated and the solids are
brought to dryness at about 105°C.
then cooled and weighed. Residue
on evaporation analyses on industrial
wastes are not usually of very great
significance, as total residue deter-
mined in this manner includes solids
that were present in the raw water
plus solids added during use. Thl
nature of these substances is more im-
portant than their concentration; this
is determined by the modified residue
tests described below.
Fixed and Volatile Rltsidues-The
residue on evaporation of an industrial
waste may be broken down into two
parts, corresponding roughly to or-
ganic and inorganic portions. Ignition
of the dried and weighed sample, at
500 or 6O(}°C, leaves only the "fixed
residue" of inorganic salts. The 108s
in weight is organic matter that has
been volatilized or burned, together
with some inorganic matter that is
volatilized, usually after decomposi-
tion.
Suspe1tded a1td Dissolved Maller-
Industrial waste solids occur in two
forms, dissolved and undissolved.
There is al!lO an intermediate zone of
colloidal particles that are not in true
solution, but that behave in many
ways as though they were. Suspended
matter includes silt, sand, precipitates,
fibers, and other insoluble materials,
Its. concentration is determined by fit-
tenng a sample through asbestos on I
~h ~ruci~le. After filtering, the
resldu~ IS d~led, cooled, and weighed.
If destred. It can then be ignited at
6O(}°C, in order to distinguish the
-------
, -. ....~. '. ~i; ~~
'. ,.!~....
'......." ~ t..;
'+,~
- -,
--.I
UNUSUAL frothing condition in aeration tank> oi the Upjohn Co. industrial
waste treatment plant. The conJilion was cort0cted by spraying with spe-
cial chemicals.
fixed and volatile suspended matter.
Dissolved matter is determined by
filtering a sample through asbestos,
then determining the residue on evap-
oration of a filtered portion. Sus-
pended matter can be determined in-
directly, by difference between residue
on evaporation in the raw waste and
in a filtered sample.
Turbidity-Turbidity in W:lter or
in an industrial waste is primarily
caused by fine suspended matter. such
as silt, clay, organic matter, and finely
divided chemical products. Much of
this material may be in colloidal form.
Turbidity is determined by ot,tical
measurements, but the various jqstru-
ments used for the tes: are not COi!l-
pletely in agreement. It is not possible
to determine turbidity in terms cf
weight of suspended matter, becanse
size, shape, and refr:1ctive index of
the particles are more important ,han
total weight. In the standard Ie"t fer
turbidity, measurement is made of Ii-
df'pt h of -,'.astc through which ,I speci-
fied candle flame just disappe;trs. The
objection to turbidity in a waste is,
of course, based ou the appearance of
the receiving stream. l\TatcriaJs caus-
ing turbidity may be of no significance
from the viewpoint of he:dth and
safety, but most people object strenu-
ously to turbid n;ttural streal.IS. so
this is an undesirable characteristic
for a waste discha rge.
Scftlca!J/e J\Iatln---C;cti-lp'bL. J"L.;o
in ~, waste represent a very obviOllS
type of pollution. Settleable matter is
objectionable in a stream because it
forms sludge banks that interfere with
navigation and chzl!lge the runoff char-
acteristics. Thc sludge banks may also
become an;teroLic, decomposing with
evolution of ohnuxiolls odors. Even
in low conccntratiDIls, settleable solids
may cover the strc:un b,.d, killing off
bottom life :lIld prevenl1l1g the growth
of hsil food org-anisms.
The deterrnimrion of settleable mat-
ter is based 011 an arbitrarv time pe-
riod. Usually this i~ one hour, al-
though a time equal to the actual
ddl'lltion til11e in rh, specific treat-
ment plant can be used instead. V olu-
metric determination of settleable
solids is condncted in an Imhoff cone
or graduated glass cOilt~_iner. A one-
liter sample of waste is allowed to
,,>ei tJe for one hOI:r in this vessel, and
the yG!U'ciC of settIecl sludge is then
,-,i)~,erv\.'r1,
'-: ,t;,:,'J[C' ,0J"I.' "1'1 abo be deter-
,-,;in.d h: ",c1gl.t. Su'>pendcd 'Ilatter
111 t)1(' urigillzd s~,llIl'1c is dekiinined
:\~; z1f'~;cril)ed l'ar]icI ; ml'anwhilt>, a scc-
ond raw sample is ;, Bowed to scttle
101' ')\l(' lWl1f and a portion is with-
dr:l\\'n from the central clarifIed liquid
;d"IIT th:' sludge'zonc and below any
!In:11;ng ,'(>]ilk This portion also is
an.1Lznl for sllspended solids, and
the difference in "uopcllded solids COI1-
lent bet \\-cen tIw t \" - ,,,tlI1]Jks, ra IV and
~(llied. i" calculated as the settleable
~o1id~
9
Coarse and Floating Solids-Coarse
solids occur in many industrial wastes,
but are easily removed by screens.
Such materials include rags) sticks,
vegetable vines, and coarse or lumpy
fractions from many industries. They
are objectionable for the same rea-
sons as other suspended solids, plus
the reason that they may clog pumps
and other equipment in a treatment
works. Coarse solids are highly un-
esthetic in natural streams, especially
jf they float. Because coarse solids
are so easily separated, their discharge
by industry should never be permitted,
either to a natural watercourse or to
a municipal sewer.
Oils-A major objection to the dis-
charge of oily wastes is that the pol-
lution is so obvious. In addition, how-
ever, an oily film on natural water
has a deleterious effect on dissolved
oxygen in the stream and on fish and
other aquatic life. Heavy oil films
have also caused death to birds and
small land animals. Even light films
of oil prevent reabsorption of oxygen
from the atmosphere into the stream,
thus hastening the development of
anaerobic and septic conditions in the
water. In addition, oil contamination
of water used for municipal supply
causes undesirable tastes and odors in
the finished water and introduces fil-
ter cleaning problems at the treatment
phnt.
Oily wastes in municipal sewerage
systems cause hazard of fire and ex-
plosion in the sewers. Heavy oil load-
ing also causes operating difficulties
at the sewage treatment plant, due
to clogging of mechanisms with oily
grit or dirty oil. Oil wastes also in-
terfere with secondary treatment proc-
esses by coating or clogging the bio-
logical growths.
There is no universalIy satisfactory
analytical test for oil. The conven-
tiol1:ll procedure involves extraction
with a volatile sclvent, evaporation
of solvent from the extract, and weigh-
ing of the residue. Certain materials
other than oils and greases are ex-
tracted in this process, causing error
in the final result. On the other hand,
sOllie greases are not fulIy soluble un-
der test conditions, thus leading to a
negative error. Oil in industrial waste
may occur either free or emulsified.
Flce oil will separate from the waste,
by floating or settling, although the
time required may be lengthy. Emul-
sified oils wilI not separate by such
-------
10
physical treatment until the emulsion
has been broken. Sedimentation and
emulsion breaking techniques will be
described later in this series.
Chemical Criteria
The physical criteria of pollution
depend largely on foreign substances
that are not dissolved in the aqueous
phase. The responsible contaminants
are particulate solid matter and oils
or other insoluble liquids. Most chem-
ical criteria of pollution, on the other
hand, are caused hy dissolved mate-
rials that arc completely dispersed
throllghout the water phase, in mole-
cular or ionic form, and that are not
removahle hy mechanical operations
like settling or filtering.
(" alar- -Color is a physical phenom-
ellon hilt its cause anrl treatment are
best discussed under chemical criteria.
Color is undesirahle in streams for
esthetic reasons and hecause it often
indicates other more serious contami-
nation. Color is not harmful in mu-
nicipal water supplies, but it is ob-
jected to hy most users. Color is
undesirahle in many industrial water
IIses. as in the manufacture of food
produCfq, paper, and textiles, wh('re
prod lid qualitv is impairt'rl hv off
sha(ks.
Indust ria I W;btC'S i1 re colored he-
calls(' th(')' contain specifiC chemical
suhstal1('e~ Ihi1t impart tfwir chi1racter-
istic color to th(' dIluent and the re
l'f'i\'ill~ strcalll Example.s of these dis-
,olved colors include m('(al ions such
as chl'On'i1te or copper. organic dyes,
amI cnl10idal materials like starches
alld soaps. Color cannot he entirely
clistinguisherl from turhiclity, and the
t 1\'0 properties intt"rfere with each
"tht"r's determination; however, both
are "hjectioni1hlt" for ahout the same
reason'i.
(-"lor sonH'times develops in the
II aste str(';1111 or tl1(' receiving water
('ven tholl/.:h the original discharge is
colorless. Oxidation of colorl('ss fer-
fOUS salts results in hrown ferric
precipitates. 1\ naerobic decomposit ion
often canses hl'drogell snlfir1e forma-
tion, which mav turn the stream black
or colored hI' read ion with meta]
contaminallts.
Thl' l1leasnn'l1lent of color is nsn
aliI' dOliI' hI' a c()lnparaliv(' tec!lIIiqll{"
bas('d nil ,I series of stand,llds tll;1t
(";\11 be cOI1l))ar('d, ejther visually or
illstlllnl('lItally, with thl' wast('. 1'h('
official standards are yellow or all1l.er
in color, and it is difficult or impos-
sible to compare these with the more
brilliant hues of, for example, dye
wastes. However, after a colored
waste has been treated and diluted
to the point of acceptability in a
natural stream, the color will have
lost most of its brilliance and can be
compared with the duller brown or
yellow of the standard.
Taste and Odor-Odors in indus-
trial wastes are objectionable when
they cause atmospheric pollution over
all appreciable area. This condition
arises from septic organic wastes or
sulfide-hearing wastes. Odor is a fac-
tor to be considered in any waste dis-
posal problem, since it may lead to
serious complaints from the neighbor-
ing community. Taste alld odor are
particularly objectionable in waters
nsed for municipal supply or for food
processing. For most industrial uses,
taste and odor are not important ex-
cept that they l11ay indicate bacterial
or other pollution.
The determination of taste and odor
on a numerical basis can be accom-
plished only by tasting and smelling.
Such tests are highly susc('ptible to
personal variations, hut no better
ml'thod is known. The "threshold"
l1I('thod of testing involvcs diluting
the sample with pure water until the
odor (or taste) can han'ly be identi-
fied. Qllalitativt" description of odor
is ev('n 1110re subjective; various
desl ripl i VI' t"nlls have been recom-
nH.'nde
-------
II>
- F...,,-
-- SM-
(19.000 ppn Q)
112
18
J 4
o
o
10
20 30
T--""", .C
FIG. I-SOLUBILITY of oxygen in water
in contact with air at various tempera-
tures.
40
causr of froth; many other industrial
products, particularly alkaline mate-
rials have the same dIect, as do cer-
tain natural stream constituents.
Frothing is particularly objection-
able in. streams, but it also has its
disadvantages in municipal sewerage
systems. In the secondary treatment
of sewage by aeration with compressed
air, the presence of frothing agents
leads to vast quantities of froth over
the aeration tanks (see accompanying
illustration). This condition is hazard-
dous because the froth contains dirt,
greases, and bacteria from the sewage.
The connection between synthetic de-
terg('nts and froth on aeration tanks
bas not heen established beyond all
question, hut there is probably a defi-
nite rrlationship.
Radioacti~,jty---Radioactive wastes,
like synthetic detergents, are a tech-
nological development of the past few
years. Use of radioactive materials is
spn'ading rapidly into many industries
and research activities, so the dis-
pOSo1.1 of radioactive wastes is an in-
creasing problem. Among the sources
of radioactive wastes are the produc-
tion of atomic weapons, the manufac-
ture of atomic power, the reprocessing
of spent atomic fuels, the use of radia-
tion material in hospitals, and the use
of tracer elements in research.
Other Dissolved Substances-Every
chemical and material used in industry
and commerce enters the waste stream
in one form or an0ther and must,
tht'refore, be considered under the
criteria of pollution. Chlorides and
hardness arr typical of the natural
l'Onstitu!'nts of water which become
pollutional elrmrllts when present in
('xc('ss. r .argr quantities of tlwse
slIhtances, discharged in industrial
wastes, are to be considered as pol-
lution. Other ciissolveci materials have
heen cliscussed above, anci toxic mate-
rials and organic materials will be
covered under biological criteria.
50
Biological Criteria
Probably the most important single
criterion for the pollution of natural
streams is the dissolved oxygen con-
centration. Dissolved oxygen occurs
naturally in all streams and is nec-
essary to maintain aquatic life and to
keep the water in a desirable condi-
tion. Dissolved oxygen is depleted
by the decomposition of organic
wastes or by chemical reducing agents.
Depletion of dissolved oxygen by or-
ganic wastes, including municipal sew-
age, is a principle factor in stream
pollution.
The maximum dissolved oxygen
content that a water can contain de-
pends on a number of physical fac-
tors. Chief among these is tempera-
ture, as oxygen, like all gases, is more
soluble at low temperatures (Fig. I).
The.greatest possible concentration of
dissolved oxygen in a fresh water
stream in contact with the eartn's
atmosphere is about 14 mgjL, and
this concentration can occur only at
the freezing temperature. As tempera-
ture increases during the spring and
summer months, solubility drops off
rapidly; at 21°C, for example, the
solubility of oxygen is only about 9
mgjL. Oxygen solubility is also af-
fected to a slighter degree by baro-
metric pressure, salt concentration in
the water, pH, and oxygen content
of the atmosphere.
The determination of dissolved oxy-
gen is fairly simple from the chemical
standpoint, but the difficulties of sam-
pling and sample preservation may be
very great. Instructions for the test
are detailed in standard analytical
references, and must be followed ex-
actly. It is necessary to carry out at
least the preliminary stages of the
analysis on the sampling site becimse
of the instability of dissolved oxygen
samples.
If a natural water contains less than
the equilibrium quantity of dissolved
oxygen, there is a tendency for more
oxygen to be adsorbed from the at-
mosphere. This .process of reaeration
occurs naturally although slowly. The
rate is incrt'a"jecl hy agitation of the
water, hencc is more rapid in a swiftly
moving stream. The rate is also in-
cr('ased by any action that breaks up
and increases the water surface, such
a~ ripples, cascades, dams, or rapids
11
in a stream. The ratr (an be accel-
erated mechanically qy stirring or by
bubbling air through the water. In
natural streams the dissolved oxygen
content is also built up by the photo-
synthetic reactions of aquatic plants.
Opposing the oxygen-increasing
factors just described are certain tend-
encies toward the depletion of dis-
solved oxygen in a stream. Addition
of chemical reducing agents like hy-
drogen sulfide causes rapid reduction
or total depletion of the dissolved oxy-
gen content. The addition of organic
matter, such as sewage or organic in-
dustrial wastes, also leads to a slower
but important depletion of dissolved
oxygen. The organic matter may not
be reducing in its original condition
but, under attack by microorganisms.
strongly reducing compounds are lih-
erated and the dissolved oxygen in
the water is diminished.
Biochemical Oxygen Delnand- The
biochemical oxygen demand or BOD
of an organic material can be defined
as the quantity of oxygen that is con-
sumed by the biochemical oxidation
of the material. The source of this
oxygen is usually dissolved oxygen in
the waste or in available dilution wa-
ter. Complete destruction of the or-
ganic matter and maximum oxygen
consumptiQn require almost an in-
finitely long time, hence the usual
test is specified as a five-day test at a
temperature of 200e. Under these
restrictions and for a readily oxidizeci
organic waste like municipal sewa~e,
about 68 per cent of the ultimate oxy-
gen demand is realized. The five-day
20°C value is the measurement whkh
is made and the BOD whicb is re-
ported in practically all tests.
The effect of biochemical oxygen
demand in a natural stream is to
deplete the dissolved oxygen that was
originally present. If the original dis-
solved oxygen is higher than the bio-
chemical oxygen demand added, the
dissolved oxygen will not be totally
depleted (Fig. 2). Actually a much
higher BOD than this can be tolerated
because the BOD reaction is slow and
there is usually opportunity for re-
aeration or replenishment of dissol ved
oxygen in the stream during the reac-
tion time.
The discharge of large quantities
of strong organic waste, however,
causes rapid consumption of the avail-
able dissolved oxygen and causes
-------
12
Saturation
~
>.
..
o
I
is
D
Tim.
FIG. 2--OXYGEN sag curve (h.avy Iln.ll" a natural stream r..ulting from
oxygen depletion by microorganisms (DI and reareratlon from the air (RI.
The time axis may also be Interpret.d as the distance downstream from the
pollution source.
anaerobic conditions in the stream.
Normal municipal sewage has a BOD
in the range of 200 to 300 mg/L, and
a waste of this character requires dilu-
tion with many times its volume of
oxygen-saturated water if anaerobic
conditions are to be avoided. Many
industrial wastes are comparable with
1\ 11111 ici pal sewage in their organic or
nOD strength, but certain concen-
trated wastes may be 10 or even 100
times stronger.
Chmtical Oxygen Demand- The
InnK time required hy the standard
HOD test (5 days) has encouraged
rhe development of quicker analyses
ror oxygen demand, based on chemi-
\'al reagents instead of microorgan-
isms. None of these tests agrees ex-
.Ktl}' with the BOD analysis but the
results may be equally valuable. With
rertain types of wastes a constant
ratio between the two tests can some-
limes he devel0pl'd. The most com-
monly used chemical oxygen demand
test (COD) at the present time is
based on potassium dichromate as
the oxidizing agent. A sample of the
waste is digested with this chemical
in the presence of acid and a catalyst.
The excess reagent is then titrated
and the oxygen consumed is calculated
by comparison with the otiginal titer.
Potassium permanganate has also been
recommended as the oxidizing agent
but is currently less popular than the
official dichromate technique.
Chlo,..,., D,ma,.d- The chlorine-
demand teit. like the dichromate and
permanganate oxygen-consumed tests,
is a measure of the oxidizability of
the particular waste plus the reaction
of direct addition of chlorine to un-
saturated compounds. It has the sig-
nificance that chlorine is commonly
used for the disinfection or other treat-
ment of municipal and industrial
wastes. The chlorine demand test
provides a measure of the chlo~ille
requirements of full scale operation.
Toxicity- The two most important
effiects of industrial waites in natural
streams and in municipal sewage treat-
ment systems are the oxygen consum-
ing characteristics and the toxicity. A
high oxygen demand is characteristic
of municipal sewage as well as of in~
dust rial wastes, but the toxicity factor
is commonJy considered to be char-
acteristic of industrial effluents. Tox-
icity is caused by specific chemical
ingredients in the waste, or by com-
binations of such ingredients. Deter-
mination of toxicity may be based
either on analysis for these specific
materials or on an evaluation of the
toxic effects to living organisms.
Increasing attention is being given
to bio-assay techniques for the evalu-
ation of toxic industrial wastes, in
contrast to chemical analyses for in-
dividual constituents. In the bio-assay
technique, living organisms such as
fish are subjected to an environment
containing the industrial waste under
investigation. The type of fish or
other organism utilized in these tests
should be native to the particular
region; and environmental conditions
suitable for the organism must be
maintained during the test. Such fac-
tors as temperature. pH, dissolved
oxygen concentration, and hardness
may have a pronounced effect on tox-
icity caused by an industrial waste;
hence, these factors should be care-
fully controlled. Laboratory tests can
never duplicate natural stream conc1i-
tions exactly, but every attempt should
he made to approach this condition
as closely as possible. Bio-assay is a
technique that is becoming increall-
ingly popular at the present time. and
is being utilized by several industrial
companies as well as by stream con-
trol agencies and research organiza-'
tions.
-------
Reprinted with permission from Inuustrial Water and Wastes Magazine.
67
WASTEWATER REDUCTION
by C. FRED GURNHAM, Editor, Industrial WastM
Head D.partm.nt of Ch.mical Engin..ring t.Alchigan Stat. Univ.rslty
T HE REMAINDER of this series of arti-
cles will be devoted to methods Jor
Ihe abatement of industrial waste p'll-
lution, which falls logically into three
major phases. The first phase is waste
reduction or elimination within the
manufacturing process itself.
The phase, second in importance
(third in actual sequence of applica-
tion), is disposal of the final effluent
to a stream or sewer, taking advan-
ta~e of the waste-assimilatin~ capaci-
ties of these flows. The intermediate
phase, actual treatment or destruction
of waste, shonld he applied only to
those wastes whi('h cannot he elimi-
nate(1 at their source ami which ('an-
not he assimilatf"d withont harm to
the re('eivin~ waters. This is the most
('xpensive phase and all pos!'iihle meas-
IIres' shollid he tak('n to red lice it to
n minimllm.
1\ n attempt to eliminate or at least
to re(llIce th(~ quantity of industrial
wastes at ils sOllne is the most profit-
111111' attack on any inoustrial waste
prohlem. Even partial SIH'Cf'SS at this
poinl almost n'snlts in a direct e('O-
nomic J!ain. The most conspicllous
tn'no in indllstrial pollution ahatement
dnring- IT''I'nt years has heen on this
phase' IIf the- prohlem.
1\11 wl't-pron'ss inonstries use COI1-
si(lnall)(' qllantitirs of water, yet little
IIr nOlll' of this water is sol(1 in Ihl"
final pr,II.
ment" puf-,Ii,hed by J"hn Wiloy & S"n,. Inc.
The reduction or elimination of an
industrial waste at the points of origin
is a task for the process engineer, be-
cause he is familiar with manufactur-
ing operations, The specific proce-
dures will vary greatly from one in-
dustry to another, and will be different
for each plant within an industry.
Engineering Design
Proper engineering design is an im-
portant factor in the abatement of in-
dustrial waste pollution and should be
IlI1ilt into the manufacturing plant
during its original layout and con-
struction. Improvemenls ('an be made
in an existing- plant, uSllally at a
~reater cost than if provided origi-
nally, hilt evell so may be well worth
while,
Multiple Sewers
1n the desi~n of any wet-process
plant, multiple sewer lill('s to convey
different types of wasIl' present lIIany
advantages in waste control, although
cost is an opposing- factor that IIIUSt
he cardully balanced ag-aillst the
favorahle aspects.
It is cuslomary, in lIIo(lem in(lus-
trial plants. to provide separate sewers
for at least three types of waste: clean
water, used but not polluted, such as
storm water from the plaut area and
uncontaminated cooling waters; sani-
tary wastes; and contaminated process
wasil's. It may 11(' desirable to keep
Ih('se threc stre:\lIIS scparate, hecansc
('ach intl'rf!'res with the' treatment and
disposal of thl' oth('rs. Evcn the dilll-
lion provid('d hy clean water is un-
(It-sirahl(' ill wasks that arc to he re-
cov('n.d or t r(';II(.d, alihol1~h the dilu-
tioll IlIay he wdconle at the final plant
olltfall.
III SOIlI!~ plants; cOlltaminatcd proc-
('SS wastes may require further suh-
divisioll with separate sewers for ('ach
I\'p<,. For ex:unple, the se~re~atin~
IIf sl rong and wellk waste.s such as
from dlllllping" process tanks and
\\ ,'ak('r rinses. Such a sepa rat ion dm's
nol in!'vitahly f('qnin' 1,\ 0 sC'\\"('r
lip(',. as tll\' sll"II!: lI'a'lI'- <':\11 "fl\'11
be handled by tank truck or by timed
discharge through the regular sewers
at night or on a weekend.
Another example is the segregation
of different process wastes in order
that they may be economically recov-
ered or treated as in the electroplating
industry, where cyanide, chromate,
and mi:;cellaneous metal wastes (e.g.
nickel rinses) must be kept separate
if any of these is to be recovered or
treated. Cyanide and acid wastes must
not he mixed to avoid hazard from the
formation of hydrogen cyanide gas.
Waste Equalization
1 'rohably more stream pollution
prohlems Or sewa~e plant troubles are
!'au sed hy uneven illdustrial waste
flow or sudden discharges than result
fmm the uniform dischar~e of indus-
try waste. Good engineering design,
even in a plant already built, can re-
duce the suddenness and the severity
of shock discharJ::es. Proper plant op-
rration is even more important but
plant desig-n is a major factor.
The led1l1ique of equalization is
simple, althou~h there arc opportu-
niti(.s for many moditications in its
application. 111 principle, a detention
tank is inr!l1ded in the waste line to
provide time for dilntion of peak con-
rt'ntratiol1s hy the weaker wastes that
pnT('de ami follow the peaks. Mix-
ing- lIlay h(' accolllplished in this de-
tention tank hy haming of the natural
flQw or hy moving parts. The holding
til11e is a maW'r for engin('erin~ cal-
culat ion and j IIdg-ll1ent, hased on a
complete knowledge of waste flow
characteristics. Adequate equalization
for ahllost any situation should he pro-
viciNI hy a 24-hour laRoon ; space for
this. howev('r, is rarely available and
the designer must he ('Onl('nt with far
Jess, S0111e times, ('v('n a 15-minute
('quali1.ation period. for waste-s suhject
to rapid fluctuation in flow or concen-
tration.
Other Factors
111 minor ways 1 he dC'sig-n (,Ilgineer
(';In aid th(' plant 1)ll('r;lting- tealn in
IIII' ahal<'l1\('nl of waste; for example,
P A. PE. 3. 1 . 68
-------
68
--
WATER RECOVERY by sedimt'ntation, cCdl cleaning and preparation plant, Pithb~rgh Consolidation Coal Co.
1.,\' 1"'" ,,1111,: '111 ", :11111111<1 1'1111'1'"
all':" \11 1'1"\"\1'111 1'11'1<1 /I,,,II.II~~I' /II
sl'lIl" III 1111:1I111"'l"i/l,:111'11]('111 "11-
gillcl'l 111.11' :'1'1'1',11' III 1'/llilli,'1 with 1111'
1'1'001111 tillil III :"I,i/'lT qll;lIltl'
1:111 (,r" /I 1,1' l:II'oIll,' 1'f'.1,1t 1"1.
1':'\"'1'1 rill 1111' fil1:d <1",'11:11 g" '" ,
n.'('('i\'!I1~ ...,tr(';1111 III t(1 (t ,,('V\','r.llrrl{T','..,
w;,'ft-" ,1,/1111.1 III' 1."1>1 ill :1" 1'1111('1'11
Ir;lkd.l [111"111 'I, 1'"'"il,I,' :11 ,III lil111'"
AI till' fin:d 1'1.111\ "IIIf.dl, III' \\ I}I'II' 1'1;lIIt 0l'f'ral"rs
,,""">! 111'11.1111,,01 tll I<-:'\I':L \'all'(' 11l1ly
J> II ti:tI" "111'11 II lilli' I", "1',lrah1e .;,
111',/'1' :1 ,,',II io'\'''11 111 thl' rill~.I' wall'r
li'll I" 1''''V''llt II"" gJ'l'atl'r Ihall 11<'<'-
"",:11 I' I 'rol'i~,ioll ~11"l1ld IIC lIIadc,
11""'1'1'1'1',101"1'\'1'111 doggillg or stop-
J>a~:" IIf Ihl' 1":,lril li"lI: all" provisiOIl
,1",,11<1 'II", III' 11>:1<1" fill' f1l1illg 11,11'
1;11,1", :tlll'l 1'Jr.;" , "111'> or ,,1111'1' rlI11\1P'
illg' 111 ,,,"1(' I'lalll, I illo(' flows ar('
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I I ," IIj I III' flow III 1'{"I'0I1S(' (I) ('Ol1dl1<:-
li,',II' "I ',111111.11 1I11':hllrl'I\1('llh 1111 till'
'.llI'liI 1 ill,,' II ""'1'.
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'1'1:1\ 'I! fll" lill'"" ill-,!t-;,d of IIr il1
;1.1<1ili"IIIII "'1' 1.1111., ~~II,'h 01'1':1\, arc
l''Ini''I,I.III, ..II, "Ii.." 1111 1I1('I:d l'al[,;
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11,111" 1:11,
I" 111(' I'k"""I":II,
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l'I,III'clllll\ 111111111111\' ',I. \',;I!II j., 1'1111
11111:' ..,111, \\111 r. \\1111, j, ::, du' :1!ay
II II I'
1'1'01'1'1' draillagl' of process soll1-
I illll~ alii I rin~(' watns from lllate-
rials ulIderJ.:oillJ.: I'rocessil1g is impor-
lal1l to wasIl' r('ductioll, l'specially in
nll'lal,fini,hing IIpnali,>tls, tile dyeinj{
or otlier l'r()l'l'~sillg !lr textile yards
alld fahrics, al1d Ihl' manl1factl1re of
\'IH'l11ical ,-r)'~lals and precipitates,
al1l1l1lg othlT indl1,lrics. As much time
a, po""i hll' shol1ld ht' allowed for
drailla~(' :ll1d dripping kick into the
I'r"\I"s lank, in Ilnler Ihat this li'IUid
Iliay hI: salvag('c\ insl"ad of IJeing
Iralls[('rn'd I" till' succ('cding riil5e
waitT a \11 1 to wa~te.
Manufacturing Process
1\1 ajor changes in malll1farturing
pn 1('('S5 for tll(. sole Jlurposc of re4lc-
fllg- slrealll polll1tion are not often pos-
,il,ll' or practical, hut should he iu-
v('~tigatt'd hc('ausc suhstanl ial h'Clflo-
1I1i('o SOl1ll'tiines I'<$ult. Authorization
I If 1,1' 'n',s chal1J.:l's is 110t uSl1ally a
'TSIHJlhihilit) IIf the l\'aslt' disposal en-
gilll'l'r IIII! lit' ~hlll1Jd make sl1ch (cc-
'"111111'1111:11 iOl1s and cooperalt' with
1111' ITS(,:tn'll lahor,l!or\' andlllanufac-
11Irillg IIil'i"illlls il1 tll;'ir ('vall1ation.
I'rlln'ss changl's for tIle I'lirpose of
!'I'dllcil1g' \\'aoll' Illav !'I'sliit il1 ,Ie-
l'1/'a~('d fill\\' of \\'i;st(. of ('l1l1al or
Iligll('J' "II'II'('l1lr;llilll1 IIlal1 lilt' origi-
lIal. III' 111;1\' k"d III rl'durtilll1 ill qllall-
litl' III p"lIlIlillllal l'IIII~lillll'1\ts dis-
,'h:ln~I'd ;111<1 111'11('" III wI'ak'T wastes
III' rI('ITl'a,,'d flo\\', I )r.hti.. pro('css
-------
~
~ ", \
....~~-&\. ~,
58
('OLD WATe'
, RINSE
.10
t
;;,'
SPRA Y RINSING of electroplated parts. Note also counter-
current flow over weir to preceding rinse tank.
- --
SERIES RINSE TANKS for recovery of electroplating chemi-
cals.
- ---
challges may chan~1.' the nature of
the waste and result in iln efflnent
lI10re susceptihle to treatll1ent.
1\n ontstandin~ ex;uupk of pro('c's
change for the JOIl!t purposl's of pol-
Intion ahatement and material rl.'cov-
cry is in the manufacture of sulfite
paper pulp, The Iraditional process,
usiu~ calciull1 hisulfite as the principal
illgll'dient of tl1(' cool,ing liqnor, pro'
dUl'('d 1'llOlinous quaulities of a Wilste
that COlll\llIol II(' salvag('d or IIl.'akd
satisfactfJ1'ily, S\lhst ilulion of lIIag'nc-
sillln, sodi1ll\l, 01 a\ll1uollil1ll1 for '1111'
('aki\l\ll I,as(' has led to plOtTSSl'S Ih;lt
p('lIlIit n'("(I\'('Jv of dH'lIli('als, inl-
proved Ileat 1'('OIlOIiIY. amI almost
("I1(\lpktl' ahatl'\lH'lIt of Ihl.' strl.'all1
1'011111 ion pro!.II'II\.
:\lIother (',s;lIlIpk is fOIiIlt! ill the
w,~)1 sco\ll'illg illd\lstlY, 1\n 1';11'1.1' slt'p
in 1111' t'IIII\'\'I',ioli of raw wool illto
usd\ll III,LI1\1f.ld\lred products is tl)('
s('(lurillg operatioll wllit'h ITIiIOVI.'S
~r('ase, dirt, :111<1 (h il'd pnspiratlon
froll1 tl\f' \\'001 liher, Thl' spent S('OIIl
liq\lor c()lIla!~:, .(S 11111('11 as SO pIT 1'1'111
of tIlt' raw \\'001 \\\'ight of litesI' in-
f~Iedil'lIl, togdltIT \\'ilh alkali('s ;11,,1
soap, It j" "11(' of the 111""1 1I<,\\'('('flli
0.,11'1';;111 polllllant'> plodll('rd hI' il1r111"
11'\', III tl1l' 11\1'1'(' 1'('('1"11 solv('1I1 1"0('
1',0.,',1011\001 "'''lIrillr:, lal\' \\,,01 i',
1('('all'rI ",tll ;111 orgalill 0.,0"'('111 iIIS((';I"
01 a rll'!\Tg"111 ,,,11111"1" (011';1',(' I,
"',1';11.1"''' 1\ Ilh 11\1' ,,,11"'111 ;",,, \';11'
III' Inu\('I,.d ,llId p1I1II1("d .I'" ,1 :1\
product. 1\ secolldary scouring opera-
1 ion with dl'fergl.'llt is still nl:cessary
l'lIl li1l' wast!' liqllor from this process
is far kss polllli ing in its nature than
traditiollal wasks from the wool in-
duslry,
Salvage and Recovery
III all industrics there is sOllie loss
III' raw lIIatcrial~ and illtermediate
Illater;als throllghout Ihe processing
npnatiolls, TIII'sl' losl lIIakrials rep-
IT:,('Ut :111 ('\'lIlIl'llIi(' l1alldicap :111<1 when
thl')' lilin thl' plallt (.tlh1l.'nt are a
cause I/f slr<'alll pollulion, \\'I1('n such
suhstances l'an hI: n'storerl to Ilscflll-
III'SS, eillwr hy salvage for re-lise ill
II", Il1allufacturing process or hy re-
roverv as a valuahle hy-product, tlwre
i,s apt (0 n'sult hoth. an easier waste
disposal joh alld a filiancial saviuR to
the c1llllpall)',
Water Re-use
TIll' IIIIIsI ohl'iol1s opportunity for
,',;tll';lgl', fr<'ql1l'lIllv over!ookl'(1. is the
r<'llse 01 watn ihl'lf withill tile plant.
--:1\1'11 1\' \1,'1' 111,11 ; ('quire partial pllri-
fi, "til/II "f tll" \1';(11'1' hilt Ihis 111ay he
('I "IIOllli, ,t! I,a,,'d Oil e~istillg water
1';111', ;111<1 S(,\\'I'I S('I I'i\'(' d,argl'-', \Va-
11'1 '" II'," r('dll('('s till' hl'dral1lir load
"II " \1,' ,1\' 1II';ltlll\'lIt 1'1;1111 al1d thll"
IH'rlilih 11\1' ilhl.t!latjoll 01 .;malln
"lIllIll', 1.111"', ;11111 otlllT I1l1ils or till'
hctter utilization of existinl{ equip-
ment. The total quantity of pollutional
material in the plant effluent may not
he appreciably reduced by water re-
cycling but the possihility of recovery
is increased and the ease and effective-
ness of treatment are improved. I
r n a
-------
Iif)
---- -
, ,.
, .
'_J ' , ~ ~ ;,
- . ,.; I "
':. '~:., j". . '. .-',
~ ~~', - :li:~ 1 t. ,:
;1.~ -c:~-
..-; _'::...~.~
,',' ~":
i "'" - «-
'f~' .
. ..,
----
I I
i
-- --- --
II
~
RECOVERY of paper pulp and white water in a closed sys.
tem. (Crown Zellerbach Corp.)
DRIP-CA TCHING PANS bewteen process tanks of a con-
veyoriled pldting machine. (Hanson-Van Winkle-Munning
Co.).
Paper Industry
III t I". 1'; 'I" I III d II 'I 1\, \\, li (' I, II<'; It.
rih('r~, :'lId 11'.< 1111 ,'h"IIIII ,01, .11'<' ,,01
v;q",'d h, Ih,. I'" v, I1l1g III \\,1'111' \V,lki
frolll I',,\)('r 11',lklllg lI,a..I1I1I(" III Ih('
p,q)(T'III:lklllg "1,('rati"II, \Val,'r thai
d';IIII, 1IIrI'IIgh II,,' ,n"I'1I (';Irri(" with
il shllrl fil)(,'I<, ,!:tv' :lIId 0111<'1 fillt-I..
alld ,'111'1111' aI, I Iii, hqlll() "I "\Vhilt'
walt.,' \\.1' ''',111,...1, d;,,'h:lrgl'd a,
IVa,1t' "'id :, 1II"j", ',111',(' IIf 11,,1111
f;"11 ;11 IIl.lIl) ,11(',[11". Thl' I'al'('r III
dll~II' I" III \'('d 11',11 ,,'1111(' \\':11"1' "lIloi
11,,1 II(" I" 1I,.('t! III" ,11"(' 1 I,.. "h'II' f iI..., '
\VOlild 1'1,"111' (' :III ;lIf('"or ~,"Idl' III
pal"'1 II I"" 11("11 I,r"v('d 1,,,,1<'\("
if II,.. II< 1<1,11:: "d"'II' I'r"llI'lh. 11'0
IlIg .1 ("I " < I I.lil" IIf 1"1111111'.1 fil,,',
;11It! 11<'\, .1", L, 11,.11 1"".111' 1 '111.0111"
i'. 11,,1 1I1I1'.1II<.t! \\'1,'1" \\,<1<1 1",'1\'
"1\ Ilil\\ .111)111 ,I 11111\('1",111,' 1",1t
fl, ,'d III 1111 1',,\" I 1110111'.111. \\ ,I!, ,III,
"t.IIJli,d ('~ 1IIIInllll'" III \\.II( I. 114 ,II.
fll"'I. 1,11"1 .11'.1 "Ii" I III<"III1,.d. ,I'
,\t." ,j', ,I ,: I ", II 11 " h II ""11 1 I' .1,. .1111
1"0111111,,,,
Coal Indud, y
111 Ih,' ",,11 1110111,'11 I' 111<"1 "I Ih,
IJilldll(1 11111111;:"'" ,I ''',I.I'l1lg "1"'1,1
t it III fll I Crllll\" IIIIJIIIIII It' ! II HII I\lt'
1'11,11111," 1111111111-:,1,1 I'"'' \t,II'. 1111'
\Va,h \\,11"1 :111<1 flllt' "'''I''''l11""1 1" It 11)("1 1 i,,,,:, III ',' ,111,
1"g'lIlh :1"'''''<1 '" ,,,a I 1111'" 11.1\'" 1>('
,,,I'll' ,.dl..",'" (';',,";:11 '" jll'I,I. 'In.,I!.;
1111-: :,II,dg(' 1>;""" il\ II" liver', f(' \\'al"I~', frill II <,k..
11"1'1:111111-: "I"'I;lIiOIl~, 1~.'a''''I\, for Illis
II "lid lilt I"d,' ill, n'ilo;('d kl\lIl\'ll'dg" of
1(' "' '"I"' "r"..,'o;<;('o;, o;;I\';"go; till" 10
lilt 1.11, al1d 1\1l,t:d "t1t~ >ai\':I~:I'a I "1111'111 "f 1",11111;011
1:\ .11"'1.11',," ",11111'1'\1" :II" Ih('d ;11
111 ,11\ 101,,,,,, I", ,I", ""'''''''''0,' (If dlrll
111111111 1111," 1\ .li"1" ,lid III ;\ "",~(T
t j, !" i" 1.1 III -I" 1111111 1111 1..1 i, f 01'111'1
III', ,1,,01, :1<11111111111,1.111111', I ,Ia~' lill('"
l'j11Q'IIWIH j"" ,I,d 1/,1' I h111t1'!!:1I1 (";1)'
411,11 lIlli, ,lIlt! 111! ,',.1111 I,t .111'1111';11111
",II ,:d",,~('.) "'i',,(I: "",,'l"li/I'" III<'
. I'"II',lr:II"...I\' 1111'1, 4Iri~:'II:l1 ;IIY!'"I-
1111'111
1\111 ( \\,11"1.... tllil .11(' ((I 1)(' 1"'("1)\'
"1",1 \\1,..,11," 1,\ "1:11'''1:11,1111 "I" I,.'
:"1\ "Iii. 1 I, ('1111"1"'. ,1,11111<1 I... l'oJ.
1111,.) III ;1<; '''lIltlltr:lI<'d :I jlll'lll ,...
1",.,,1""" :tlld 111:1\' I", .'''''lIll'li,IIl'.) hv
1111' 11',(' "f 11'11Ilil'''' I'''''' 1:0111-" .','ill1
,,,,,"11-1,'111 "'111 tl"" "f \I II," '1"11<'
\'.11 ,,,111, 1"1"'1"'1:010'<1 ," \"'" "lIlr;II('.(
1",,,111'1..111 I... 1"1111"1",<1 .III"'" ,,,
Ii II' I.I'.IIIII~ [;III"~, \I 11,'''' it 111111,,11,"
111.1""111' "f 1",;11 11':11('1 :11101 ''''IIIIIL:
,1111111<".01, \\',11," ""''''''"..1 11""1 III<'
,,,,"1,.,, ,,'I I', t""I''''dll\' '''1,1,,,,,,,1.1''1
. , I); I' HIli. 1.11 1111 I WI ,IU'-,C II l' 'I ~ I : ' I (' , I I
~ofll'lIillJ.:' "I' otlwr treatment hefore
,(' IIS(',
1011 ('xchallgc lcdmi'lues are used
""I' I h(' r('('oyery of chemicals from
pial ill~ rinsl's, especially for copP<"r
and nickel salts. Hecent advances in
the resin industry havc also I) lade
possihle Ihe concentration and recoY-
ery of chrolllates hy ion exchan~e.
(>crasiollally SOIllC constituent of a
waste: slrealll rail ue salvaR'ect as a
I',I'-produ{,t even though it cannot he
n'covtTed for re-use in the process,
I\e-use !IIay he prohihited hecause of
(ollt;uuinal ion by other wasles but this
1II'('d uot pn'vl'nl recovery in a differ-
('III fol'lll. This recovery of hy-prtld-
ucts frolll a waste stn'alll is not oftell
pradical hut should be consid('I"('d ill
I'lalillillJ.:' for ;1l"u~1 rial wasIl' disposal.
Food Processing and Fermentation
III I h(' fnod 11I;lII"faclllrill~ illdus.
I ric, ally 1 11011 <'I';al Ihal ('nters Ih('
\\,:10;1,' stn'alll \:\'('11 al'l'idl'ntally (";UlI1ot
I... [('('ov('rl'd ior primary pn;dllrt for
1111111;111 cllllslllnplion. .This material,
howner, may II\' hi~h in food valuc
and may he \'('covrrahle for the pro-
dlldion of animal fl'("1. \Va!itc's of
~Iill Jown quality {'all sOIlH'tinll's he
1'011\'...-1('«1 10 olh<'r h.v-products such
a, technical graill's of fats alii 1 oils.
glll(' allil gelatill produds, or fertilizt'r
I1lal<'l'j;ds, In, th(' £l'nllelllation indus-
I ri,'". ~1"'111 J.:'rains rl'l'ovcn,(1 !Iv
,,'I "I'llilig an' prol'l'ss('d for use as
",ltI'" food alld ('olllprisl' an ('ssential
pari of Ihl' il1du"trv's ov('rall enmom,V,
'1"11<' l'Iassical alld wdl puhlkizec\
""ll1lpl(' of by prod,...t rc('overy from
-------
an industrial waste is the manufacture
of vanillin, a synthetic vanilla flavor,
from sulfite pulp wastes. This process
provides the major amount of vanillin
consumed in the United States, but
since only a small fraCtion of the
organic matter in the sulfite liquor is
converted to vanillin, pollution is not
appreciably redun~d, althou~h it does
pay for a substantial part of the cost
of furthl'r wastt' tr{'atm{,lIt.
Plant Operations
Prevent Accidental Discharges
. It is nevn possihle to eliminate
{'omplete1y accidental discharges of
process materials into the waste
streams. Proper plant engineering de-
si~ and maintenance plus alert oper-
ation will do much to prevent such
accidents.
Com 01011 causes of spills include
tipping of small containers, breakage
of hottl('s and other fragile vessels,
slopping of li(llIids during transport,
and overflowing of process tanks, All
of these and spills from other I'aUS(,S
arc avoidable.
The design ellgineer ('an plan tallks
that will not tip, choose contain{'r ma-
terials that resist breakage, install pip-
in~ systems to avoid manual transpor-
tal iOIl of chemi('als, ami provi(lr float
valves or alarm syst{'ms to prevellt
overflows.
TIll' plallt 0lll'rator must also do his
share in this pro~ram. For{'lIwn alld
olhers of tl1(' ;lIlrnillistrativ{' stafT hav\'
Ih,' lask of k('('ping tlwlllselves alld
('V('I Yol\(' (,I", forever alert to pn'v('lIt
accid('lIts,
Dripping and leaks
Drips amI leak, arc ille\,ital,l{' 111
any pron'ssin~ of liquid materials, 11111
Illese should hl' eorr{'cl<,(1 or counter-
actl'd as promptly as possihle amI ill
a relatively permanellt IlIanner. Rou-
tiue inspection alld IIlaint<'nance oi
kllowlI trollhle spots may corre('\ trou-
hIt' I)('fore it a('\uallv O(Tllrs,
Dripping from work in process as
it passes between tanks or processing
areas can usually be counteracted by
drip pans, spanning the space be-
tween tanks and sloped to return
drippin~s to the tanks from which they
came. Leaks from the packing glands
of pump" and agitator shafts are
hound to ol.'cur in spite of efficient
routine maintellance ; provision should
he mad(. that sllch leakage will not
cause trouhle or add to the waste
disposal prohlt'lII.
Rinsing
Wh{'re a solid pro(lud is succes-
siVl'ly treated or processed by a vari-
ety of soilltions, rinsin~ is a necessary
operation, Suhstantial quantities of
pnH:ess solution nmy he carried into
th{' rinse watns and from there to
tlw sewer. This loss of process solu-
tiou Ot hn t{'chniques ind\1lle the IIse of
~q11('('Z(' rolls on ('xtil(' mal('rials. air
blasls 011 plat('(1 work, and centrifu~e
"pnat iOlls for granular IIIah'rials.
Drainage
\ \,hellt'\"('r a soli(1 tllalerial is pilSS-
illg hd~'('('n p1'(\('ess tanks or. fr01l1
pro('('ssing to a rills('lank, a prololl~ed
drainag(' tillle cloes 1I1I1('h 10 re(luce
t'arr\'-ovl'l' b('l\\'l.'ell lanks. Thc time
61
which can be permitted for drainage
is usually limited but it should be
made as long as possible u~der the
existing circumstances. In electro-
plating with automatic conveyorized
equipment, the work should be lifted
from the tank at least one station
before the end in order to accomplish
as much drainage as possible. In elee-
troplatin~ hy hand o~ration, the pro-
vision of a hook over the plating tank
to suspend the rack of plated parts is
far superior to expecting an operator
to hold the rack by hand for drainage.
J n the dairy industry. milk is often
hrought to the processing plant in
metal containers which are emptied by
inverting them over a recciving tank.
Usually only a few seconds can be
allowed for drainage time; if this can
he increased even slightly there is an
improved recovery of milk as well as
lessened pollution from the cap-wash-
ing waters. Increased drainage time
can he provided by establishing two
or more drainage stations for each
operator.
Waste. from Cleaning Operation
Clean-up operations in industrial
plants result in the .formation of
wasIl's that differ somewhat from nor-
mal processing wastes and are not
always tre<\table in the same manner,
J n the foo
-------
Section Eleven
ECONOMICS AND EQUIPMENT GUIDE
Economics of Pollution Control Systems
Product Guide/1972
-------
ECONOMICS
POLLUTION
A. H. Phelps':' and G. F. G all * i.'
OF
I
INTRODUCTION
It would be desirable for your purposes to
have a tabulation of cost.s of cont.rol per cfm
of gas controlled or per pound of material
collected. This would orlly be possible if all
the many variables in a control installation
could be held constant except cfm. There
arc many obvious variations which prevent
this tabulation having any general application.
Some devices cannot be compared on a
dollars per cfm basis because some devices
will not apply for some problems. S02 cannot
be controlled by combustion, for example,
or air containing great quantities of particu-
latc! or moisture could not be used in an
absorption system without extensive pre-
cleaning. Gf!ographical factors will cause
va riation due to diffE-rent degrees of control
required, availability of fuel, water cost,
etc.
These variables can be held fairly constant
for each of you in your own area with a given
industry. Thus, it should be possible over
the years for you to build up a tabulation of
dollars per cfm for specific control problems
most common to your area. Consideration
of the factors in the cost of control systems
follows for your use in developing such a
tabulation for your own problems.
II
COST FACTORS
A Equipment
The particular problem faced and the
particular industry will often dictate the
specific method used. A cost tabulation
for comparison between several alternate
methods will not be ncc('ssary when the
coni rol is dC'tc!rm ined by the problem.
n Size
ObviouHly the cost of cquipment incrp.ases
with th(~ size and, in gcncnll, increases
CONTROL
SYSTEMS
with the volume handled. One factor used
for a rough estimate of the cost of one
size unit if the cost of a different sized
unit is known is the so-called six tenths
rule.
cost2
cas t 1
i 0.6
= / s ze 2 )
~ ~izel
This rule may be applied to the entire
cost of a system or just to the cost of
individual elements of a system. It is
not safe to use when the range of the
equipment sizes exceeds ten to one.
Common sense will often dictate that the
rule be ignored. For example, the cost
of a smoke stack does not increase at the
. 6 power of its height but obviously at
some much higher rate.
C Location
This applies to geographical factors men-
tioned in the introduction such as varying
degrees of control, varying availability
of water, fuel, etc. For a given city it
should not be a major factor. Although
even here, devices using great quantities
of scrubbing water, for example, might
be more desirable close to a river than
at the other end of town.
D Auxiliaries
1
Air moving equipment such as fans and
their drives, blowers, hoods, and
dampers.
2 Liquid moving equipment such as pumps,
vessels, agitators, piping and valves.
3
InstrumentR for measurement and/or
control of gas or liquid flow, tempera-
ture or prcssure, operation and capa-
city, effectiveness (smoke meters.
analyzing devices).
~. H. ~~lP~-:--Eng~neering Oepartment, Proctor
C.F. Gall, Cost ~stimatinR Department
--------
and Gamble Company
PA.C.ge.20.l2.65
1
-------
Economics of Pollution Control Systems
4
Colleclion media such as chemical
solutions and t hei I' Gttendant mixing,
supply, storage, recirculation, etc.
E Piping
Liquid: approximately $2/in. diameter/
ft. purcha8ed cost for carbon steel lines
wilh relatively few complex connections
0[' controls and around 2 to 4 in. diameter.
Installation cost would run $1. 15/in.
di~ll1lf'lt'r/ n. The latter figure is less
~lccurate than the purchase cost.
Gas: ductwork, hoods, cabinets and other
sheet metal for the control of gas flows,
Gpproximately 609 per pound purchase,
GO ~ per pound installed.
F Electrical
Cost of starters, switches, wire conduit,
motor control centers; total at $400 per
horsepower.
G Requirement for Larger Existing
Equipment
1'11(' addition of equipment adding pressure
drop to a system or the addition of a
sY8tem requiring additional horsepower,
may often require the replacement of
motors, fans, pumps, ductwork, stacks,
and so forth if they are already operating
at maximum capacity. This incremental
load can sometimes be the final straw
that breaks the electrical capacity and
requires an additional substation or major
power supply to the plant. The same is
true for water supplies, cooling or heating,
steam lines and even sewerage. The
addition of control equipment may either
require replacement of these overloaded
facilities or loss in productive capacity.
H Building and Equipment Structure
Space must be found for the installation of
this equipment, the site cleared, possibly
improved, possibly sheltered. New
structures may be required for support
and the problem of the last st. raw just
discussed may occur here. Thus, footings
may at. In8t be 0v(!rloGd~d, support
2
steel within the building be overloaded,
and a distant location required or exten-
sive revision of existing buildings and
structures.
I
Special Considerations
1
Special materials because of corrosion,
for high temperature, erosion or pro-
duct contamination may be required.
2 Insulation of equipment to prevent
freeze-up, loss of BTU's, or injury
to employees.
3
Weather considerations:
loading, bracing, flood,
supports.
wind, wind
earthquake,
J
Class of Equipment
A major production facility operated at
full rate will require heavy duty equip-
ment that will not require continuous
attention. Temporary installations,
marginal installations, .low profit instal-
lations at minimum cost may utilize an
entirely different class of material with
an entirely different price rating.
KOtheI'
This heading includes the category of
items often included in what estimators
call "other costs. II This would be sales
tax, if applicable, at 10/0 to 30/0; engineering
of the installation and design; contractor's
overhead and fee; escalation at 5% per
year, if these figures were used for com-
parison from year to year for repetitive
installations; and occasionally research
necessary to develop the solution. These
will total about 60% to 700/0.
III
OPERATION COSTS
A Utilities
1
Electric power assumed at 1-1/2 cents
per kilowatt hour. Horsepower - $60
per horsepower year for 3 shift opera-
tion. Pump horsepower approximately
$200 per year per 100 GPM per 100 ft
-------
of head - :i shift opC'ration. Fan horse-
power $12 per 1000 cfm pCI' inch of
H20 static pressure - 3 shift operation.
2 Water varies between 10 to 20 cents
per 1000 gallons. In some areas sewer
surcharges arC' based on water usage
and should bC' included in our operating
costs. The sewer taxes are in the same
order as water costs - about 1Ot;/1000
gallons, depending on the locality and
type of sewage treatment plant.
3 Steam approximately 50t;/1000 pounds
or approximately two million BTU's
for a dollar.
4 Fuel costs for direct heating, excluding
cost of operating the equipment or
capital costs, etc., would be 25~ to
35t; per million BTU's. To attain a
figure this low, in some areas it may
be necessary to use coal, in others oil
and in others gas. In specific areas.
one fuel may cost a great deal more
than another. Number 6 fuel oil ranges
from 35t; to 65t; but can go as high as
95t; per million BTU's. Firm gas can
be as high as 70t; per million BTU's;
interruptible gas 25~ to 50t; but in some
areas it is nQt available for the whole
winter.
B Chemicals if Required
On a very rough basis exotic chemicals
cost a dollar a pound. industrial chemi-
cals cost It; to lOt; per pound. Chemicals
used in control applications such as acids,
bases or salts, run in the It; to 5~ per
pound range.
C Disposal
This item must never be ignored in any
air pollution problem. It is very easy to
turn an air pollution control problem into
a water pollution problem. Factors to
consider under this heading are the storage
of collected materials. treatment of the
material so as not to provide either a
nuisance or a hazard and conveying it.
Conveying may include hauling to a dump,
trucking, sewers, piping, etc.
Economics of Pollution Control Systems
D Recovered Costs
This can reduce operating cost by recov-
ering materials with a marketable value
or a reusable value. It is possible but
not likely. that it could even pay for the
equipment. Very small operators without
the engineering backup to avoid a problem
will usually be dealing with quantities
too small to justify much recovery in the
first place. Larger corporations with
great savings to be made. should have the
kind of management to identify this and
install the recovery equipment before
pushed into it. A most likely opportunity
for recovery is where the gas stream is
rich in an ingredient used by the corpora-
tion itself. If no sales distribution and
quality control problems are required
for resale to outside people. the possi-
bility of savings is more likely. One
example might be salt cake in a Kraft
mill, or sulfur dioxide in pulp digesters.
Systems which can recover a portion of
their cost do occur but run the risk of
depressing the cost of the item sold and
thus decreasing the ra:te of return.
E Maintenance
Assume 50/0 of capital cost per year which
is equivalent to 20-year life: 5% for re-
pairs and expenses, thus. 10% total for
maintenance.
F Replacement or Rejuvenation
This applies to adsorbing units for cata-
lytic combustion units. The replacement
cost of chemicals used in the scrubbing
system have already been covered.
G Use of Capital
This is the cost of money used to purchase
the pollution control equipment. This cost
could represent interest charged on a loan to
a small company for the purchase of this equip-
ment to extend the payment over a comfortable
period. (If capital were available to make
this installation without borrowing. it im-
plies that some return could be made on this
capital.) For larger corporations this di-
verts funds which might have been used in
equipment expansion usually with a much
higher rate of return than 6%.
"
-------
Economics of Pollution Control Systems
WATER SCRUBBER FOR 50,000 CFM
Carbon steel equipment used throughout this system was for two 12 ft. diameter by
24 ft. high carbon steel packed scrubbers using water once through for cleaning.
The cost estimate is for an actual installation.
Item
Material
Labor
Total
Scrubbers
Supports for scrubbers (13 tons)
13, 200
9,900
Duct and elbows
8,500
Supply pump (7000 GPM, 100 ft.
head 30 HI'), pump foundation,
now meter, and back pressure
control valve
36,400
Construction Subtotal
68,000
21,000
Engineering
Subtotal
89,000
7,000
Plant supervision
Total
96,000
Composite indcx(l) for construction
cost when this unit was built was
156.1.
Present index is 174.0.
96 000 X 174.0 '"
, 156.1
107,000
(May, 1965)
(1) The composlte index is a private construction index,
but one :oimilar to commercially available indices.
4
-------
Economics of Pollution Control Systems
ACID SCRUBBER FOR 5.000 CFM
An absorption system involving scrubbing of dimethylamine from 5.000 dm of air
using glass lined 18" diameter glassed absorption column. packed. Equipment in-
cludes the acid scrubber recirculation pump. acid scrubber cooler. mixing tee for
scrubber neutralization. acid blow drum. caustic delivery pump, and caustic stor-
age tank. This cost estimate for an actual installation.
Item
Material
Site clearance
Yard and underground
Building
Equipment Structures
Equipment
Piping and insulation
Electrical
Subtotal
Inspection and controlled items
Sales tax
Premium time
Maintaining production
Indirect personnel
Field office and fee
Subtotal
Engineering
Subtotal
Contingency
Total Cost
Labor Total
500
40
260
1.000
12, 600
8,000
1,500
23.900
600
360
980
10
9,180
35.030
7.180
42.210
1.790
44.000
(May. 1965)
fi
-------
Economics of Pollution Control Systems
CATALYTIC FURNACE FOR 50,000 CFM
An air preheater to bring exhaust gases up to about 6000F. Furnace size at about
15 million BTU/hour with not very much insulation or refractory, thus, lightweight.
Replace existing fans for increased pressure drop. This cost estimate based on
costs from similar equipment.
Item
Site clearance
Y:lrd and underground
Building and equipment strudures
I';quipment
Piptng
Elpctrical
Totals
Unlisted items
Subtotal
Inspection and controlled items
Salc~ tax 3-1/ ~/o of material
Indirect personnel
Field office and fee
Subtotal
Enginl't' ri ng
Sublotal
Contingency plus escalation
Total Cost
(j
Material Labor T atal
200 2, 000 2, 200
2,400 8,000 10,400
8,500 5,000 13,500
83,000 14,000 97,000
1,000 3,000 4,000
12,000 2,000 14,000
107,100 34,000 141,100
10,900 4,000 14,900
118,000 38,000 156,000
2,000
4,000
38,000
200,000
38,000
238,000
24,000
262,000
(May, 1965)
-------
Economics of Pollution Control Systems
CATALYTIC FURNACE 5,000 CFM
Air preheater to 600oF. Furnace about 1. 5 million BTU I hour. Not too much
insulation or refractory. new blower and ductwork. This cost estimate prepared
for management I s consideration.
Item
Material
Site clearance
Building and equipment structures
Equipment
2, 220
11, 500
250
500
Electrical
Piping
Subtotal
14,470
Inspection and controlled items
Sales tax
Indirect personnel
Field office and fee
Subtotal
Engineering
Subtotal
Contingency at 5%
Total Cost
Labor Total
700 700
3,560 5,780
3,595 15,095
750 1,000
1, 400 1,900
10.005 24.475
500
350
10.000
35, 325
7,000
42,325
2.000
44, 325
(May. 1965)
.,
-------
Economics of Pollution Control Systems
COMBUSTION OF MATERIAL IN A FURNACE FOR 50,000 CFM
Heat 50,000 cfm to 1, 3000F for complete combustion of material. Use heat ex-
changers to preheat incoming gas and discharge from stack at 600°F. High tem-
perature furnace will require much brick work about 105 ton installation requiring
new fans, motors and drives. This cost estimate prepared for management's
consideration.
Item
Si tl' clearance
Yard and underground
Building and cquipnwnt structures
Equipment
Piping
Electrical
Subtotal
Unlisted items
Subtotal
Inspection and controlled items
Sales tax 3 -1/ '2f'/o of material
Indirect personnel
Field offict-' and fee
Subtotal
Engineering
Subtotal
Contingency plus escalation
Total
8
Material Labor Total
200 2,000 2, 200
2,400 8,000 10,400
8,500 5,000 13,500
239,000 42,000 281,000
1,000 3,000 4,000
12,000 2,000 14,000
263,100 62,000 325,100
26, 300 6, 200 32, 500
289,400 68,300 357,600
2,000
600
68,000
428, 200
87,000
515,200
30,000
545,200
(May, 1965)
-------
COMBUSTION 5,000 CFM
Heat 5,000 cfm to 1300°{<' to destroy small
amounts of material. This requires about
5 million BTU/hour. For such a small fur-
nace no heat recovery would be llkely. 5
million BTU/hour is approximately the size
of a small package boiler for 5,000 pounds
of steam an hour. Package furnaces can be
bought for something in the range of $10.00
per pound of steam per hour. Thus, no close
estimate was made of this particular process.
If we were to have such an application we
would buy a package boiler, vent the gas to
the boiler for combustion and use the steam
somewhere in the plant as a recovery method
for the cost of operating the pollution control
system.
Thus, the cost of this is about $50,000
(May, 1965).
Economics of Pollution Control Systems
ADSORPTION SYSTEM
These systems were not estimated in great
detail but costs of them were derived from
vendors charts. This is a basic system of
steel construction, air cooler, blower, ad-
sorber, recovery system with condensor and
decanting tank sized at the assumption of 5
gallons/hour or organic material per 1,000
SCFM of air.
The unit for 5,000 cfm was estimated at
$70,000. If a pre-cleaning scrubber were
required for particulate or aerosols which
might plug the carbon beds then add $ 20, 000
for that, giving a total of $90,000.
The unit for 50,000 cfm would cost approxi-
mately $330,000 and if a preabsorbing scrub
ber were needed on this one for the same
reasons, it; would cost approximately $100,000
as per our initial estimate on the 50, 000 cfm
water scrubber, thus bringing the total of
$430,000 (May, 1965).
9
-------
Economics of Pollution Control Systems
TYPICAL COST BUILD-UP OF AN AIR POLLUTION CONTROL DEVICE
50. 000 CFM SIZE
Vertical Array
Horizontal Array
Assume .1 package which sits on a foundation
mdepcndent of the process equipment and
supports and tied in with simple duct con-
nections and auxilinries.
Difficult job. Same equipment installed
among the process equipment. Requires
structural support above the building and
relocation of existing materials to fit into
the process.
Carbon Steel Equipment
Carbon Steel Equipment
100 Base
+ 10
2
Purchase the equipment
Labor to install
100 Base
+ 2 20/0
10
3
4
15
12
20
11
20
2
4
2
2
17
35
56
10
5
2
Clear the site
Yard and underground
1
11
Building
Equipment supports
Instrumentation
20
10
Piping and ductwork
Electrical
lG
2
1
Design contingency
Inspections
Sales tax
o
o
Overtime
11
22
Existing facilities protection
Supervision
40
10
Field office charges
Engineering
Field cont.ingency
lOO + 1GG
2GG'70
100 + 245 = 3450;0
Note: Above is for air pollution equipment. For liquid pollution control the total would be
bet ween 350 to 5000;0 of equipment purchases.
10
-------
Product Guide/1972
The Joornrtl of the Air Pollu.tion Control Association presents its fifth annual
directory of air pollution products. This 16-page guide lists manufacturers of
cmiAsion control equipment and air pollution instrumentation under product claaai-
fications which are shown below. These classifications are derived from McGraw-
Hill's Air Pollu.tion Handbook, chapters 10, 11, and 13 . The final portion of this
guide contains an alphabetical listing of manufacturers.
If any manufact.urerl-1 or pronuct categories have been inadvertently overlooked.
the omissj~'J1 ;s n~/!:rcltf'd and F:hould be brought to the attention of the editor. It
will result in a more complete and accurate Product Guide/1973 to be publimed
next December.
EMISSION CONTROL EQUIPMENT
Inertial Separators
Cyclone separators
Mechanical centrifugals
Impingement separators
Scrubbers and Washers
Spray chambers
Atomizing scrubbers
Deflector washers
Mechanical scrubbers
Spray nozzles
Fabric and Fiber Collectors
Cloth filters
Fiber filters
Baghouses. complete
Other Control Techniques and
Apparatus
Electrostatic precipitators
Sonic precipitators
Settlin~ chambers
Catalytic equipment
Fume incinerators, direct flame
Incinerators, liquid waste
Incinerators, solid waste
Incinerators, gaseous waste
Incinerator burners and controls
Trash compactors
Fans and blowers
Gas absorption equipment
Gas adsorption equipment
Other chemical techniques
Odor counteractants and destructors
AIR POLLUTION INSTRUMENTATION
Samplers and Collecton
Gas samplers, continuous
Gas samplers. interl'flittent
Filter samplers
Electrostatic coUectors
Cyclone collectors
Impactors
Automotive exhaust samplers
Dust jars
Lead peroxide cylinders
Sulfation plates
Gas sampling pumps
Analytical Equipment
Wet chemical
Spectrographic
Spectrophotometric
Mass spectrometry
Chromatographic
Electrostatic
Colorimetric
Conductivity
Coulometric
Fuel cell type
Photometric
Microscopic
Analytical balances
Precision calibration gases
Miscellaneous Inltrumentatlon
Ringelmann comparators
Flowmeters
Pltot tubes
Air velocity meters
Data logging and telemetering
Recording meters
Smoke indicators and alarms
Meteorological instruments
Particle generators
Dynamometers
-------
INERTIAL SEPARATORS
Cyclone Separators
Aha!! .l1lL';III<'L'1'II11; Ltd.
Al'rud) Jil 1 ),,\ 1'lrIJlIlIt'ut COl'puratwn
\, I'Od.l"" 1\1a..1,1I1<'1)' Corporalion
TII<' ,\!,\d l\lalllllaL'lUrll1g Company
All' l'ollul">n Il1du,(rll" tl1C
rile' ,\11' I'lllwall'f CIIIII;I;tn.~:
.\ 'I' c;.I."1'.- III'.
1:('~j,:.1'1 11-( '0111'1'11, 1111'.
1\1''''111111'' ('(llIln.l. Int',
~al'g,."t- '\C\" 1J1\'I~i"lI
Zurn Indusl!'1' '~, iiI(',
CHllld,' IJ c;, I",,",!<- (;OIlIpany
:;~\"'r~k.\ EI, c llflllat\lTIl Corporntion
~F Prlldlll t~ (.':1 11.11 I:t Lld,
SO" "'1'.,,' 1 1,,,111'1 1'1 a I Ftllers Co.
Tn-:'\I.-r (:111'j111r:lIJOIl
rol' \11' ('"",, '"'" l>il'ision
l'll!I"d ;\ld:,11 ('lIfj,orntion
\\'t ,"{I I'll I'r4 f'ipll:1111I11 I )J\,ision
J«I,' f\1.11I1I1 L"I IIIIII~ Cumpnny
Impingement Separators
Abarll':"I4I'" "I'III~ I.ld.
At'wJI 11" ~J.,d,II" ry C"rJ,omtion
Ai" P,dltll!IIJJ Jlldll'l:ril~. Joe,
,\Ir ~\'~It illS 1)1', j,"'WJI
Z1.f'll hltlut-'Irtl "', IrH',
.\II."I'II'I1F1 \\1 l'lIt,,1' Co 111('
\11111'11':11. \ 11/\ TOHL!;I'r"I: CO;IIOrlllioQ
:\r~\1 PI:c~,'lil' I'I'ndllf'l:<\ (:nrnptU1Y
,\IIII)lI;'I!I,,' Illlh'H'1' (~l', bu'.
B, B, HII" 1.\",1 & J\,-';1iocintvs, Iuc,
HI.'II ).;11/,':'111" IIII~ ('o,np',n.\'
110' II I)" '-1"'1 I..,,, 'I'II(",'h Corp.
1'11. C'II"o\" ('OllijlllllV
Cht'llIj,':'! ("\l1.'..II~lI'llOil ("nmpA.ny
II .\1.1:, lill'h C1JlIIP:1I1\
I)u...; ('('11'101 (\IIIIJI'IH,',
1)11:,1 =--1111\ 'I', ".~ 1'11\ J IJ('.
})II:o-IJ \ J I~YI"'I\lH
1:11'1'11'1' BI,,\\,!' Co., In(',
1.';lrI' (\'~Jql:IJ},\'
r"Ir.-.. I "II>!"(:'.I' (1)1 ".,.[) I'roduc(s)
II, ,I h"" ,.", j':fjllip1II,'nl Corporation
~LIIIII(',' \ hl1wh!. CUllipany
J\o(~b !,~I~.ill" J ir:l!; ('0" hH',
hlljlf' I... ( '1111'1 ,ilL', , f 1\.
T: ~', \ 1,1111 ." ( "1111 rllll' \
\1, 11'111', FilII I (''If! 11"lli..u
.\/1 hi:' '1'1': . ", III' ..h ""h'crizillg
.\1111'1111" f\ ,
dill!' ,101 d'l' 11':-1 , III'
:'\,,: I q, I I IJlIJ) 01111 ,.
'"~ H'II" 11.('qllft 'tl III"
~:Irl!( nl, '-., '\' 1)1\, 11'11
/'\1(\, Illd 1 .1 ! I' ", I lit
:--iI,llIlill' 'I',.; 1\11' /10111'. ('OIJlPRUY
"'iI, \111. Iii"
TIIIII '.1 ,1111111 II!!JJIj..:,1 'ilIIlPUIIV
"nil',} .\1, I "lIr( ''i"ltH,'lll1n '
\ II I I. ',' ~ I !II'
SCRUBBERS AND WASHERS
Sr>ray Chambers
,I~, ;'0(: ',j:P'!'''I' n ( '!rpllr;d.iun
\:1111 "" 111'11'1 ""I (',Irpc'ration
.\11 ".J; " IIl'kstri,... IIH'
\ II ...., t, II, 1)1\ )'1 I!, ' ..
Z 'ill Il,dll ,I n"~, Ill.
\111' rlt III 11111\' : "III' l ,I Inf',
\iI,1 1\' ,j, \ ;111 '! 1'1.," 1111 Cnrr,ornfioll
\..' I ,j 1...:1110 ,.,' "llIllatioH
\'1 ,.: I~' l'r",!II"!~ (;on1pan.v
I~ j\ H I 1 ,I ,\ \~,""I:d(''i! Ihr.,
H"I I 1~:I,,"'III' ('lIlIoP'1I1Y
, I.. 1',11111,1111 (' 'tIll"'" ('r"rpurntll,n
~ " ,1 ('! ,\ I , I I ,
I~II II I I" t 1"11 I II' II ,I, "II Corp
II II tTa I ' r,lrLI ( ,):I.P:111\
II",,:. '"I I",.
("lip 'i' ("I1J ,llt"ll
'; II (', .14 ", ('<11111 !III\"
, 'I" 1111 ,I I "H,~I,II.II'III (~I'rnIHlny
r I' I' I, ,III, 'I I III ,~"'I)I'III'lt,,,,, f nf'
, \11 '" I ",, :,,('.
DeVJIt...i.~ Company
Dravo-DoyJc Company
J)uall Jndus(ri,.s Jnc.
Tlte Dueon Compuny
Dusl Control Compuny
Empire IIIDIIl'r Co., Jnr'.
Fuller C..mpallY (Draceo ProducUl)
Joseph GOllt.r Juclllcrators, Inc.
H,.1I Proe,'ss Equipment Corporation
1. 1'. C.Indl\sll'i,'s Inc,
Industrial Pbstie Fabrieators, Inc.
Jnl.l'\'IHilion:tI Pipe and Ceramics
Corporalion
The Joltnson-J\luf('h Corporation
Mallrie" A. Klli~hl Company
nodi EJlgjn"I'J'jn~ Cn" Inc.
KopJlI'l's ClIlIlpany,lne.
Krd.s Jo:lIgin"l'rs
:lI":\'lIliir, Ineinl'rut.ors, Inc.
:\11 KHOPt:L (formerly Pulvcriaing
Machinery)
:I'lill l"dIlSI'I<'H, In('.
]\.Jor'H" Bonlll,.r Division oC
1I1I/o(:Jn IlIdllsl ri"H, 1111:.
:\lIllllnlll Irwin, ralo,' Corporation
:oll'nl!:,'r (;"rl'"rnrion
I )l'IIvo-1I1II J,. Company
Dllall Inrlll.,fri,.s Inc. .
Th.. DU('lIfI Com pliny
Fr'ror Svst<'mH
F"II"r (\"npHny (Dencro Produc..)
J,I)H~'ph r;"dN Illcincrnt.ol'8, Inc.
H",I.l'ro,',',-:-" E'I"ipm~nt Corporation
111\\ -:11"1'1111 Jndn"r~lor Group
,,()\,tltIHI {"orpnration
I iI,. .'ol''''",,-~I:or'''' CnrpOrl\tiOD
-------
(; ..\ I,kl:ili!t'r Company
1\",,11 E'lgin,'erlllg Co.. Inc.
I\())lpl'r~ Conlpn.n,\., Inc.
h n I" EII~m"l'fs
I., I'I."lIhy Coml'.iJlY
H. (;. Mahon Company
!III h HOI'{TL (fumll.rI\, Pulverizing
!\!:t..hillPry) .
111111 IlIdllol.''I<'S, III".
\:1'""".1 ))lIo[ Coll,.(.tor Corporation
:\orlun COlllpany
I',."hody EnKin"Nin~ Corporat.ion
H,'s""rl'h-Col.t.rell, Inc.
Ht ~()\lr('f' Control, Inc.
:-;"r~"III.-NCY IJ,dsion
!.lIrn 1udllslr;,'s, 111('.
:-;..1111111' "lid J(,wrtIIlK Company
:-;"\','rsl...\' 1<;1.','1 fllIII,l.om Corporation
:-;10' I'rudlld~ Canada Ll.d.
:-;""".",,.tllldIlSlnal ~'ill.ers Co.
:-;'lLlldard IIRvellS ~}'st.,'ms
Tnilor unci Compnny I Inc.
1'1" 1';"~II1(,"fI'd I'mdllr!s Corporation
I;"il..d Air Sppcialisls. Inc.
II()[' Air Cortl'di(," Division
\ :lrI-~\'SIt'IU~, In(',
WHd,. 'Cornpa,,}'
\\ t'slt'ru 1'r""'l'i'alion Division
.Joy Manuf:tcturing Company
Deflector Washers
A,'rody"c MRchil1pry Corporation
Air Pollutioll I ndllstries, Inc.
Air Syst.prns Division
~lIrn Indll,tri('s, Inc.
AIII;"ol Corporntion
llrul,,' C. E. & E., Illc.
Buffalo For~e Company
'1'11<' c,.ileou' CompallY
Comhust.lon Eqll;pnwnt As.'!Ociat.ps, Inc.
P,.Yill"s.' Comp,,"\'
])IIBlllndllsln,'s Inr.
1'10.. Dllcon Compllny
'I.-II Pro..,...., Eq'"f'm"nt CorpofHtion
I I' (' It.dllsi rips I nc.
'l'h.. .I"lIlIo,,"-I\I/lr..\. Corporation
h,it'll En~II}t'f'nnli!: Co., Inc.
'1'1... II C. 1'.1:11"", Company
1\1,'NH.lllin Inl'llll'l'alnrs, Inc.
~ 111\ HOl'll L (["''''''rly PlIlvl'rizing
MII('lIinprv)
1\1 "I IlIoIlIo'.rll's. Illc.
MOt"'. flolIll(l'r I )ivi.ioD of
llal(an Induol ri,.., Inc.
'\:tllonrtll )H~;I ("11111 dor Cnrporalion
'\ ..rtCln (;t'mpany
PI 'tlllld\' FI1I.!1I1I,.'rin'-! ('I)I jlDrafion
1{, ,..arrb-('ottrdl. hII'
Hl'sl)\lrc~ ~;olltrolt Tnc.
"'''r~t'nl-NCY Division
1.lIm Intlllstrips. Inc.
('I.IlId,. n ~I'hnr.bl.. C"rnpany
-..:. \ 4'r...k\' 1':1"1'1 ronatonl Corroration
\\ IV ~I." !lbnnbclll,;nl!: C"mpan~'
,"':'IIII,'ml'l Induslrial Fllkrs CO.
I',,,,,..! Air "p",';nll-ls. Ine
1 'nj\'f'l"Ral Inrinl'r~I"r (~nrpnr:ttion
Mechanical Scrubbers
\I,nrl l"II~ln", ,i,,~ Lt.1
\Ir P,dIIIIIHI1 IlIdll...lri!'~. I.H',
\ 11 "\ ~ I., III'" I) 1\ I. i I! II
/'II!I. IlIdll III' "', Jilt'
\11i' II III '11 I II'. r ('{\ , I,II'
AIILI tit' III 1\111\, )1'1.1 ('" .1111',
,\ 111"1 JI :1/1 \' :111 ')'. qll.~f n'lI ('ol'pnrfalioD
Antqllli ('IIT"!IC,r:tliflr\
'\11"1111.111",11'11"" (','rpnrnfion
B H Ihr..tlllil ,~. ''''''III'j'II,'s, r'H'
nd,,, "..1111111111 ("'lIlrrd ('orpnrntion
IInll,' (' F .\- 1': 111,'
1\111 11 1)1 \ 1~1i'11 I'll \ III II '" " ( 'nrp
HIt/Lilli ""n>" ('IIIIIJIIlfI\'
"III ,';111,111111..111111 ("'IIIII:III.\'
'1'111' «'I Ikllk ("11111"1"\'
(" Idn-:--':pr'l\ f't!llll\r:dlflll
('1"'11111':11 {"IIII' "'11 lit'li ("'1111)1;111\
COlllhuHIJ"n Eqlli"nll'l1t Associates, Inc.
Coutin('nl."l Air I'rod,"'ts, Inc.
Dollinger CorporalioD
DlIalllndusl.nes Illc.
The Ducon Company
F,'ror Systems
Fulll'r Company (DtIlcco Products)
H,'II Process EivlRllln
":"'I'ir,. mow"r Co.. In"
Fillrnlion ~'"III""H
Flj'x-Klec1t Cflrpnrntion
F"II"r ('011'1""" (Otllf"'O Prodnrts)
{iloh" 1\11.:111\' (~nrporalil)n
11,.". (;"1.1""",, ,t, Cnmplln\'
O;vi,ion "f florlinll,oll IndURlrir<
Thl' .Tn'ln!tlflll !\f'IP II e/\rpol':tfion
U. A. Kleis.l"r Company
Thc H. C. Mahon Company
Menardi and Company
Mercury Filter Corporation
MIKROPUL (formerly Pulverizin!\
Machinery)
Mil-An Manufacturing Corporation
Mill IndnBtries, Inc.
Modern Dust Bug Company, Inc.
Mount. Vernon Mills, Inc.
National Filler Media Corporat.ioll
ReeB Blow Pipe Manufacturing COIIII",r,)'
Research-Cottrell, Inc.
W. W. Sly Manufact.uring Compau)'
J. P. Stevens & Co.. Inc.
Summit. Filter Corporation
Torit. Manufacturing ComJ;'allY
Western Precipit.at.ion Division
Joy Manufact.uring Company
Wheelabrlltor Corporation
W. C. Wiedcnmann &: Son Inc.
Fiber Filters
American Air }i'ill.... Co., Inc.
Johns-Manville Products Corporllt.jou
Mill Industries, Inc.
Research Products Corporat.ion
Wheelabrator Corporation
Baghouses, Complete
Abart Engineering Ltd.
Aerodyne Development. Corporation
Aerodyne Machinery Corporation
Air Pollution Industries, Inc.
The Air Preheater Company
American Air Filter Co., Inc.
American Blow Pipe Co" Inc,
American Van Tongeren Corporatjon
The Bllbcock &: Wilcox Companr
B. B. Barefoot & Associates, Inc.
Budl Division, Envirotech Corp.
Buffalo Forge Company
The CRrborundum Company
Carter-Day Company
Chicago Air Filv,r Company
Combultion Enfl;ine!'rinp;. Inc.
Dollingpr Corporation
Donlpy Bros. Company
Dust Control Company
Dustex Division
Empire Blowl'r Co., Inc.
FIl'x-Klpen Corporat.ion
Fnllcr CompHnv (Dracco ProduclH)
Glohl' Alhany Corporation
Th.. Johnson-March Corporation
G. A. Kll'is.,I..r Company
The R. C. Mahon Company
Wm. W. Mpy"r and Sons, Inc.
MIKROPUL (forrnl'tly Pulverizing
MRchin,'ry)
Mill Indusl.ri"s. Inc.
Pr..ripitair Pollntion Control. In"
ReI's Blow Pipe Mnnnfaciminl\ COIll,,'III\'
Hesl'ar<:h-Col tl'Pll. Inc.
Rn"ml'lin Mnnllfllel.nrinl! Company
SI.. Lonis Blow Pipp Rn,l HI.awr (':01111"""
Acvrrsky I%.ctronat.om (':orporati"n
W. W. SI.v Manufac!.urinp; Company
Tnilor and Company, Inc.
HOP Air Corrpct.ion DiviRinn
Unitrd MrCoill Corporation
W"s'.rrn PrrcipitAt.IOn Di,'ision
Jov Manllfudllring Com pan"
Whp'"IRhmtor Corporat.ion
W. C. Wip
-------
Amencan Standard
Belco Pollution Control Corporation
Buell Division, Envirou'l'h Corp.
IBW-Martin Incinerator Group
OVltron Corporation
Koppers Company, Inc.
The R. C. Mahon Company
Preclpitair Pollution Control, Inc.
Hesearch-Cottrell, Inc.
Resource Control, Inc. .
S(,v(,l'6ky Eleetronatom Corporation
SF Product>! Canada Ltd.
Sonic Development Corporation
United Air Specialist>!, Inc.
DOl' Air Correction Division
Wade Company
Western Precipitation Division
Joy Manufacturing Company
Whrelabrator Corporation
Sonic Precipitators
Full..r Company (Dracco Products)
;;"v,'""ky EleclrnnRlom Corporation
S~ttling Chambers
Affiliated Incinerator Corporation
Air SvsLRma Division
"'"m I ndustri('s, Inc.
Amt'fi"'\n Van Tongeren Corporation
Brule' C. E. de K( Inc.
11"..11 Division, EVlrot,'ch Corp.
Cartt'r-Day Company
Oonlry Bros. Company
F'"'H.r-Klosterman, Inc.
1',,1I,'r Company (Dmcco Produc~)
Kopp""" Company. Inc.
1\101'6" floulj(('f DivisIOn of
H"!!;/ln Indllslril's, Inc.
Pro "II',t.air Pollut.ion Control, Inc.
H"SfHlr('" Control. Inc.
:-;"r~' nl-~CV Division
Z"rn Indualrics, Inc.
1""\'ITs,,1 Inrinl'rator Corporation
\\" ""rn P,,'ripilation Division
.10' 1\1"n1lf,,"'''rin~ Company
Catalytic Equipment
II, ),.,. 1',,)),,I;on ('ontrol Corporation
1',11:11, I... 1'....hll:Is Intcrnlltional Inc.
I',II!!! 1I1:lnllndtlstrH'S, Inc.
,..,,11, r (:'""p:m.v (Pmc"o Products)
11011....11111 Atlas. InC'.
\I) 1\ 111 )/'1 I). (fnrml'rl.v 1'"lvprizing
\f:I4'IIIIlI'rv)
1\" (',"")I'~t. IIH'.
'I'\" mllll H'''':lr..\' and Enl(inl'l'rillll
('(11 poratlOn
"( IP \ir Cnnl'I'linn I>1\'iAion
\\',Hlt, ('Olllpllfl)'
Fume Incinerators, Direct Flame
\ 1,1< (jorpnrJ1linn
\11' 1',dIIIIlClI\ Indw.;tri('R, fur
1'1". -III' 1'1',",,,,~I,'r Company
\lhlll' 1':nl(llI1'ennll; Corporation
III~, I"w-Liplnk Corpnrnlion
1\",1,,- C. K & E. Ine
)1."" ('ol'porlll'on
( '" I 1 "",1: Produ..Is.lntt'mntional Inc.
("":,'j]I~llOn Englfl('I'rmg, Inc,
I '"",I '",' ",n E'l"ipnu.nt. AS80cillte8, Inc.
) I"I"""\' Ov('n Comp"ny
"'fo:('()
.11'-"1 ph (;I)df'r In('In('rlltor~t Inc.
I ."rdol,.PinH, Inc.
II ;1" ('omh"" inn EnJ(in..rrs
""..h 1':"!!1n,',-,'inJ>; Co.. Ine
'11". II (: Mllhon Company
\I'I\',n Premix Burner Co., Inc.
't'!1 1,,raceo Products)
JOl:ICph Goder Incinerators, Ino.
Hirt CombuHtion Engineers, Inc.
Hydro Combustion Corporation
IBW-Martin Ineinerlltor Group
Ovitron Corporation
I. P. C. Inuustri,'s Inc.
Koch En!!in.,..rinl( Co., Inc.
McNIl\,lin Ineinrmtors, Inc.
:\lilllrul1\st.ri('a, Inc.
MOl'ae Boul!!"r Divis",n of
Hagnn Industril's. Inc.
~ntional Airoil Bllrn... Co.
~orth Arnericlln Manufacluring
CompllllY
Oxy-Catalyst, Inc.
Pr"neo Division
Pi,'kllnds Matl".r an,l Company
Pyro I ndu"' ries, I n('.
Hi<-ht('r,IDc.
RoSl! Enl!in,'crinp; Division
Midlnml-Ho,,", Corporation
Snr~,'nt.-NCV Division
"'mn Inrlustri,'s. Inc.
:-)lIrfll"" Comhllstlon Division
!\1 it! la 11,1-1 toss Cn rporn tion
TlI,lor and Coml'nnv
TIIi.rmnl R"s,'ar<:l, oDd EnKineerinK
Corl>ornlion
'(',,"'nn Limiter!
tJOP Air Corr,'l'Iinn ~ivision
tJnlINll\1,'(;ill CorpornllOn
I rniv{'r~ml fllcirll'rn.tnr Corpnrulion
,John Zink Compoll.'
Incinerators, Solid Waste
.~mliilt.,.d Inri'lI'ralor Corpoflltion
1'1,,' Air Pr,",,, ""'I Compnny
.\"",..eon IIlo\V I"l'" Company Inc.
.\ mrriean I nl';III'rn' or Corporation
lIil(,.I.-.\\'-I"l'lilk Corporal Ion
IInrl,.' C. J.:. & E.. 111('.
)1:-;1' ('"rporn, iOIl
I!lirll-Zol. IIII'.
("'I'llfil'd JHt'lu.'ralor (;ompnn.Y
('I"I'I.l:Ind COlli rob. 111<:.
(:,,",1011"' ion Enl!inl...rillJ>;. Inc. .
<'I)IIIIo1\Slio" Eq"iprn, "I Assoriatr8. Inc.
(;011\1 ro. Inr..
1I1'lroill'ltok,'r Company
flollt.,y Bros. Conlpany
Dorr-Oli\'l'r. I"r.
ElI\pirl' IIlo\\"'r Co. Inl'.
FIIII"r ('01111''''''' (I)rilr,'o Prodllcta)
JUSI'pll f;odl'r (']('Jnf'ralnrs. Inc.
H,rt. Coml",,';nn EnI/III"I'rs, Inc.
]lyrlro Cornhll,'ion Corporation
IIH\'-\1',,",n IlIem"rator (;roup
0\'11 !'OH CorpnrA.tlon
I. P C Inth'RlrirR Inr.
1''''''''ri,,1 fllow Pip,. Company
1\"1-1" rs C"mpnny. Itl<'.
'II '\' 11JIII) '1I.'iJII'ralnr~. 1111',
Mill IlIdllalr;es, Inc.
Morae Houlgc'r Division of
Hllgan Industrics, loc.
National Airoil Burner Company
National Incinerator Corporation
North American Mnnufacturing
Company
Plibrico Company
Pyro Industries, Inc.
Hichtcr, Inc.
Sargent-NCV Division
Zurn Industrie8, Inc.
Surface Combustion Divi~ion
Midland-Ross Corporation
Tailor and Company, Inc.
Thermal Research and Engineering
Corporation
Tre(:an Limit,-u
Univel'Hal In('inerator Corporation
Wade Company
Incinerators, Gaseous Waite
Affiliated Inciut'rator CorporatioD
The Air Prehcater Company'
Alkar Enllineerinl( CorporatioD
American Incinerator Corporation
Bigclow-Lipt.nk Corporation
Brule' C. E. '" E., Inc.
BSP Corporation
Catalytio Product8 International IDC.
Chemical Construction Compauy
Combustion Enginl)cring, Inc.
Combustion Equi~ment A8IOciate8, Inc.
Fuller Company (Drae,'o Product.)
Joseph Goder Inl'inC'rators, Inc.
Hirt Combu8t.ion Enginpers, Inc.
Hydro Combustion Corlloration
Koch Engineering Co., nc.
McNaulin Incinerators, Inc.
Mill Industries, Inc.
Morse Boulp;pr Division of
Hagan Industrif's, Inc.
N ationnl Airoil Burner Company
North American Manufacturing
Company
Oxy-Cntalyst, Inc.
Proctor de Schwartz. Inc.
Pyro ]ndljstries, Inc.
RoSA EnglDl'erinj( Division
Midlnnd-Rol!8 Corporation
Sargrnt-NCV Di,'ision
Zurn Industries, Inc.
SevPN'k.\' Elrctrollatom Corporation
Surfnrr Comhu,tion Division
Midlund-R('8s Corpnration
Tailor and Company. InC'.
ThPfmal Rrlit-Ilrl'h anrl Ehgin"ering
Corporation
.I. T. Thorpe Company
Tn'eRn LimitC'cI
UIP Enltinerrl'd l'rodurt.s Corporation
Universal Inein,.rator Corporation
UOP Air Corr..etioh Division
lTnilrfl McGill Corporation
John Zink Company
Inciner.tor Burners and Controls
A Ikllr EnKin;.rrinK CorporatioD
T!", B"rher Manufacturing Compauy
Brul..' C. E & E.. Inc.
nurling InstruuII'lIt Company
Comh"" ion Equipnwot A"",,('iAtC8, Inc.
Jo:dips" I'u..! Enjliint'ering Compaoy
JoS('ph GodC'r Incinerators, Inc.
(:ordon-Piatt. Inc.
Hirl. Combllslion EnjliinC'l'rs, Inc.
Industrial COmhllstion Inc.
Mllxon Prrmix Burner Co., fnc.
l'vk~lIulin Inrinrrat.ors, Inc.
:\-lirl-Conlin,'nt Metal Proflucts Company
:\1111 Ind1\stries, Inc.
'1'1,,' !l:ort.h Amrril'Rn M:llIufacturinl!
Compnny
1',.,,1.01/)' Enllilll'C'rinl! Corporation
'1"" 1:111 l.imi"'.1
I flli,'<'I'S") Inrinrrator Corporation
Trash Compactors
Air Poilu' ion Indusl.ri,.s Ine
~ml'rif':'n-.I""nson CompRc~r Co., Inc.
-------
/\1\1'" FooJ S,'rvlce DIvIsion
Auto PRk Company
Combustion Equipment Associal...s, Inc.
Compactor Corpomtion
Construction Products Co., Inc.
ElcclroDlc Assistance Corporation
Ennronmental Pollution Research
Corporation
E-Z Pack COlJ1psnv
Intt"rnational Dyn~tics COf\)orlll.ion
Mil-Pal'Sysl!'ms
PI'llbody l<~ngim'Ning Cnrpomlion
I!,'search-Goltrt'll. Inc.
SI.jpntilie Pollution COllirol Corporatioll
Tn-I'ak
Fans and Blowers
At'rndvUl' M:\I'hi1H'r,V (~tl1'J14Ir:lllnn
Tht' Agt'l 1\lllnuflldul'ln~ l\IIIII'II".V
Till' Air Prl.ht'Ht4'r ('pmp:IU.\'
. \.r Hvslt'ms 1)1 \'I,s'PIl
Zurll I ndust rit's, 111<'.
lllIrr~' Rlowt'r Co",pnny
lIulT"lo Forg., ComplI".\'
('arl,'r-DIl\' e""'''"II)"
l ~omhustillT1 EItJ!.illt'I'l'ill~. 111(.
(lUIIII In.lustn!', 111<'.
(;lIr'r; I'll 11 .'.1:iI",fa"'lIril1~
(\llnpnny
"\orlon GO"'P:IIIY
Tr;-M.'r Corp<>ral iO!l
Gas Absorption Equipment
A.. I'ollul.ioll IlIdllsni,'s, In".
.\IIH'fU:1\n Van 1'IHlgl'fl'n rorpnr:lljon
:\rl'o lnrlllstril'~ ('(trporalitHl
II H. Bart'f.",t & A,,'ol-i,,!..s. III",
B'Tt) En~'IH"'rin~ ('(Jmp~lTn'
( '11I'lnical COlist 1"111'1 inn ('OI1lP:III.\'
('ornbwdion Jo:n~!lnl'l'rill~~, hl!',
('olnhust.ion Eqlllpfl!I'nl ,\:-:...twi:tks, TIIC,
1)laJHUIHI Pnw('r :--;IH'('ialt~, Cflrporajinn
"H,hf'r f:ki.'nldi.' ~ompfin:-'
J'1I1I,'r C",nl':iI" (\)r;I("'o I'rodllcts)
II, II 1'rrH'j's.~ lI]I:J. \ II' ,I, ,I (' Irh.'11 1>lvi.s;.'n
("11;":"111 ('I If IlIlr~1 r I' .11
.... \, 1-,\,\ II" '!I'n'lllIllI ('"rpor:1I1/1II
...:, )"', , I f ~ "Ie'
,"" \I:III,IJ 'p" III illL' ("\IJII':fll\'
\\ '1,1, (\"1>11:111"
\\ I!' 'I ('11< 'lIi,", I
Other Chemical Techniques
\I!" PI, ,'" "I"dl!' I ('111111':11.\'
H, I,' ('I., Inil':!!'
')'j" 1', d,',Ii. ('110:1"111\'
("'"111111.../ '"11 ""I/'i'll , 'Illy' I fll'
1'1110 1"';"'11 fllIfi.' CII'np~I"\'
J.' II It I (', ) II \ , "111 \ I I 'I ']< . t I J' 111/ II I" I, ~
II, "'1, ,', 1'11111'111' rd "'111"'1'111'111
The JollII,,,,,-l\1nreh Corporati""
MaurieI' A. J\l\Il!;hl Company
Mt!di-( ~"mp Il,,~,'llrt'h & Development
Corporation
MJKIlOPUL (formerly Pulverizing
Machinery)
MinI' Safl'ty Appliancps Compaoy
Hesource Control, Inc.
Tailor nncl Compnny, Inc.
WadI' Company
Odor Counteractants and
Destructors
A in'ndol' Corporat inn
!\irk,'"" , "e.
Air Pollution Indu8tries, Inc.
Atlantic Ultraviolet Corporation
Brule' C. E. & E., Inc.
Caru8 Chemical Co., Inc.
Cpntri-Spray Corpora lion
Combustion Engincp,ring, Inc.
Farr Company
Honeywell
The R. G. Mllhon Company
Maroon Division
Borg- W al'llcr Corporation
MIlt.hpson Gas Products
Rhoclia, Inc.
SeveNlky ElC'etronatom Corporation
Surfll,'e Gombust.ion Division
M)(lIand-Ilos.~ Gorporation
IInit./'I1 MeOill Corporation
SAMPLERS AND COLLECTORS
AIR POLLUTION INSTRUMENTATION
Gd!o SamtJlers. Continuous
AIIII~flcaH \'an ~J'I)nf!;1'rCn Corporation
Allu8 EIo-t'ln<: »"VICI'S Company
B:lt h""lt.h I"dllsl.rialln~trum"nt
( ~!)l))paIiY
lI"d,'y M..t.l'r c.IIlIl'any
TlI,' Bcudl\. Corporalloll
C"IIhrat"u IustruIIIl'nts, Inc.
e '1..\,.lalld COlllro1s, luc.
C" ,SI'I)U Equlpllient Associatcs, Inc.
\\ . 11 (:..rl.lII "nd Compuny
Tlw I )"ellr CltI'm;,'all'rodllcls Company
1 ):n):,,\ I list rHUll'III,,,;
1),,1,,1.. IlId".';lII'.'.
f ),,\ 1:0 1 Samplers. Intermittent
\1" (:1,1' ' If1t'nq'flr~,11 d
\If >";:lllqdllll~ ~\",fl'lIJfoi, IrH'
\/1\1 I It','!! 1 1\11,1,,1' ('.If]1II'',''1
\111' 11 II' '': 11')'1' 1111'
I ,I 111'1 I 1II'If II' I), \ 1'1011111"111 1111'
Hnl'hnrneh Tndll~triT\1 In~trument
Gomrlln\'
Bud".\' M"lt.'r COInpullY
TIo,. H. nuix CorJl0rtltjon
Calibrnl('d IlIfltnlllll'nfs, In('.
Compllct Air HalllpJI'rs
Cop".-Yu)"nn D,visIOn
Blaw-Knox Company
Thl' DUI:nr GI...mi..aJ Products CompBDY
])('vro Ellginel'l'ing Incorporated
Ellison lust.ruml'nt DIvision
DIeterich Stnnnur'
W. II Cllrtin IInd Company
Tlte p",.:t" ("'I,,'mi,':d Prodllcls Company
)';lIisfm In- 1 nll1l1'l1l I )I\'i~i()n
Oi"",,,;,'h ~IIilld"rd Corporation
(;dm:111 Instrllrnf'nt Company
G,'nerlll Metal Wnrk.<, Inl'.
(;In", 1IIIIIIv:tliClII~, 1111',
Jnh'rl('rh Cnrpnl':1finn
~fdJ'nnirs AR~O{'lal",', Ine,
M..tiJ..r J'J'trull1' nl ("'''I'rorntion
Mi,'Iorn..!",,,,;,',,1 :-;1'1'c;nlti,'~ Company
Mllli!HQ',' rnrpnr:1Jjon
Min" ~"r,'lv Appli:II"'I's CompaDY
":d 1",,:iI ',"" i"iI,",entllllnqf.rumentq,
IIII'
Pn'j'I"'/llfI ~('if'tljiri,' rnmpnn,\'
It<-:, '1I.,.h ;\l'pli'II1"" ("'''rnrnny
~"hlllidl '1I',lrlllll"1I1 ('qmp~ny
,'--', i. 1111(1., (:I:I~'" 1\1,.\\ III!,! Cn , Tnt'
'~"!II"f,-,'1 T"dll~'!II:d Fill, r,,,, ~n
-------
ThO' Rl.flplpx Companv
Von JlrnncJ Filt.prin~ nl'cordel'1l
If 01' Air (;nrrpr.!.ion Diviaion
Wpa','rn Precipitat.ion Divi8ion
.Joy M"nll("rfurin~ Company
Electrostatic Collectors
Applied Science Division
LI Uon Systems Inc.
Enviroumental Rt'Brarch Corporation
Gardnrr Associatl's, IDC.
Mrtronics A&BOciat.rs, Inc.
Minp S..fdy Appliances Company
'1111'011111 Envlronm"ot..1 Inst.rumrnl.s,
Inc.
Th,'rmo S.I'st.'ms, Ioc.
Cyclone Collectors
Act' GllISB Incorporated
Alrtiow Dpvrlopments (Canada) Ltd.
Anlt'rlcan Vall Tongeren Corporation
] )ustt'X Division
Wm. W. Mt'yer and Sons, IDC.
\'" 1 II>nul ":nvlronmental Instruments,
!rll'. -
:"." "tlli,' (;1"" Blowing Co., Inc.
c;olllt'rSl.I. Industrial Filters Co.
Impactors
AndC'n;on Sampl,'rs & Consult.inll; Service
ApphC',1 Sciener Division
L,UOI1 Sysu,ms Inc.
1':II\'lfOlHlIt'ntlll n,'scareh Corporation
(;""IIII'r A""OCI"t..S, Inc.
1\1,',II-Coll1p 1I"""flreh & nevelopment
( \lrporntwl1
1\1o'1,'orololl:)' 1I""'llrch, luc.
\1",,' :,,,fPt.y ApplillDp,," Compllny
Automotive Exhaust Samplers
'1'1... Iknlhx Corvorstion
Pn 1\', 's..~ I nst fumPD t Dlv.
('llroJllslJoy AmNican Curporl\tion
(:I:l\ Iou Mllullfacturinp; Company
I klphi I udlls! ri,'s
I), 'HO EUjI;l!\",'nng hworporatecJ
Vn\'lruM"tnc" Inc.
Envlr!ln1l1l'nhd Data Corporation
hn irnllmcnf On" Corporation
I ,II,'rtf'ch Corporati()f1
\1, dl-CUlI1f' KI'se,neh & Developmcnt
(~n!l 'Of!! hOD
.\ltfJ" Sa(,'I,y AppliRnc,'s Company
~"',..t('o Engin~ering
Olson LlIlwmtori..s Inc.
("'Nlc"" 111"l.rum,'[\I, Co., loc.
('ursd I II"
HEM lu,orl'0r:>I..d
C'""I' H"",'sr..h LRhofllUHII'S, 10".
:--;1111 1':11'ctnc Cnrpontlion
1'111' '" ;-';I'n~nr:-.. I nr.
\">1' 11<-,",,1 I, illl'riuj( H,'"ord....-
Du!.t Jars
'\Ir(low I), \ !'!lJpml'nt.8 (CannclR) tld
('{lrn"'~ J ,nhnruillfll':i
l'r1 (.I~inn S( It'll I "1(' CCHupltny
11,-,1'111'1,11 Applinllf'p Compnllv
"':11, IT.Tnl' ~1Hntlf:!dllnnt{ (;01111"1"\ rnc
lead Peroxide Cylinders
c 'urr\lng Laho1r3trniNI
I{ 11 rll'l (I
"n'I'I"I/111 "";/'H'nI1t1" Cnmp:1ny
1\":--"111"11 Aj,phnnr(' Compony
.~ 1\, I-TI'I' ~hnllf!l('fllrillg (;(), Tn,.
Sulfatlon Plates
Cnrning I,ahoratories
Harleco
Prrcilion 8d,'n I ifi" Company
Gas Sampling Pumps
Calibrated Instruments, Inc.
Gut Manufacturing Corporation
Metal Bellowe Corporation
Peerle811 Instrument Co., Inc.
Scientific Industric8 Inc.
Science Pump Corporation
".- ... f
ANALYTICAL EQUIPMENT
Wet Chemical
Atl8.8 Electric D"vices Company
Automllted Environmental Systems, Ino.
Beckman Instruments, Inc.
Calibrated Instruments, Inc.
W. H. Curtin and Company
Dohrmann Instruments Company
Analywcal Instruments Division
Fishcr Scientific Com~pany
G"lman Instrument Company
LPeds &: Northrup Company
Litton Systcms, Inc.
Mettler In8trument Corporation
Monitor Labs
Philips Eledronic lu"l.ruments
Procell8 A nRlyzers, Inc.
Scientific Industries, Inr.
Tl'chnicon Corporahon
Wilkcns-Anderson Company
Spectrographic
American Instrumcnt Company, Inc.
Applied Research Laboratorie8
BaJrd-At.omio Inc.
Rausch & Lomb
Beckman Instrumpnts, Inc.
Farrand Optical Co., Inc.
In frR-Rpd Induatrial Systems Division
Jllrrell-Ash Division
Fisher Scien tific Corn paoy
Peerlell8 Instrument Co., Inc.
Spectrophotometric
Automated Environmental SY8tems Inc.
Bsird-Atomic Inc, '
Barnes Engineering Company
Barringrr Re""..rch Ltd.
Bausch & Lomb
Beckman Instruments, Inc.
Cnlihrat.rd Instruments, Inc.
("ombustwn E9,uipmeut AS80ciatea Inc.
Cousolidlltl'd Elcrl.rodyusmirs '
f:nrpomtion
W. IT ("litl in :1,,01 C"mPllnv
j",,,,II, I ~I I' 1111111' C.Hnpany
Ilorll'\'\\I,lI
hil':I,'I/,.d 1,,,10,,',,:1) ""sIems n"';blOn
'''''ro,II-A,'' 111\"""'" .
."'!'It.,'r :--I1'If'1I1 dlf' (~(lllIpany
1\1":1' SlIf,".\' Apphlln,w8 Company
'l'h" P..rk in-Elnll" Corporation
1''''''1'" ":I,'clronl(' 1 ,,"trllmen18
Rp,.!'tron",'rirR of FI,)ridR, Inr.
\\ dk"f1" ~I\fl"rs"" ('''lUpony
Mass Spectrometry
Aero Vac Curpora I ion
Beekmfln In8trumcnts Inc
Colibrnto-rllnSl.ruml'nt", I~'c.
Ml'di-Cornp R"spflrl'h & Development
Corpuration
Thp P,.rkin-Elnwr Corporal ion
, Chromatographic
Ace OIall8 Incorporated
Analytical IDllt.rument Devclopml'nt Inc.
Barber-Colman Compllny
Bl'ckman In.trumen18, Inc.
Chemical Dat.a System8, Iric.
W. H. Curtin and Company
Disc IDlltrumeat.t, Inc.
Dohnnun Instnlment.t Company
Analytical IDlltnlments Division
Farrand Optical Company, Inc,
FiICher &: I>orter Company
Fiaher Scientific Company
Gelman IlIIItrument Company
Leeds &: Northrup Company
Matheson Gal Product.t
Medi-Comp Research &: Development
Cor(loration
Mine Safe~ Appliances Company
National Environmental Il)8truments,
Inc.
Packard Instrument Company, Inc.
The Prrkin-Elmer Corporation
Philips Electronic Instruments
Process Analyzei'll, Inc.
Science Pump Corporation
Scientific Systems Corporation
TRACOR Inc.
V srian Acrograph
Victoreen Instrument Division
VirTis Company
Phornix Prc(.i.ion Instrument Div.
Electrostatic
Thermo Systems, Inc.
Victorern Inslrument Division
Colorimetric
Atlas Electric Devices Compan.-
Automated Environmental Systems, Inc.
Bausch .t Lomb '
Beckman Instruments, Inc.
ColJlpact Air Samplers
W. H. Curtin and Company
E. I. du Pont dr' Nemours &: Co. (Inc.)
IlIIItrumrnte Products Division
Fishf'r SCIentific Company
Houston Atlas, Inc.
Intertech Coryoration
Jarrell-Ash DIvision
Fisher Scientific Company
Leigh Instruments Limited
Litton Systems, Inc.
Medi-Comp Research & Development
Corporation
Mine Safety Appliances Company
National Environmental Inst.ruments,
Inc.
Pollution Monitors, Inc.
Precision Scientific Company
Resource Control, Inc.
Technicon Corporation
VirTis Company
Phoenix Pr(.cis;on In~trumf'nt Div.
Wilkens-Anderson Company
Conductivity
Beckman Inst.rllml'nts, Inc.
Calibrated In8t.nlmrllt', Inc.
Coult.P.r Electronic.lllndll~trini Divi8ion
Davis Inltruments
The Foxhoro Compan)'
Infrll-Red Industrial Avsll'ms Division
Intrrt.P.ch Corporation'
T,r't'dij &; Northrup Comprony
Lit.ton Syst.('ms, Inc.
Min,' Safety t\ppliau"f" Company
TRACOn Inc.
Coulometric
.'\ tills Elf'ctrir Drvicf'S Company
B"r.kman Instrumr.nt.- Inc.
CnhhrrttccJ Instrumf'nt". Inc.
Hon,'\,\\'cll
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11111'rlt,dl ('nrpIIIHtlnn
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11)1I11J1"; 10'1, I'Inlflit' II1:-.II'lIIll"1118
Fuel Cell Type
FII\ j,..j\II'lrif':-' In.'.
Photometric
,\I'rOlllllfllllll' I h\ 1:-11111
J'hd('o-Ftlld l'I'lptll,~tltlll
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!l1"II,ar Division
'\IID" Snft'l)' .\1'1'11:1111"" C"mp,m.\'
:'\t,lwlco EnJ,!;lItl'f'rjnj.:,
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it IlIs('h l~ L01ub
l'l~il,'r Sl'II'!HI:II" 'omp,lny
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h t1l'T ~r j, rtllt), ( 'IlIp'III.\
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Precision Calibration Gases
.I, ,1\ 11,';d J 11"1 ill!,"!I! 1)1 \ I IlIl'mt 111 Inc,
J\latI1l'sl'll (::h Pr'1lI\l\.'I'-I
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>,1011 HI'" tll i: I tlI!JI'dllfll", Jnr
MISC. INSTRUMENTATION
Ringelmann Comparators
Ihlll'v !\.-fi kr t'tl!:!!':I!!"
('It'\'I',llIod ("HlIrlll~, IT1/'.
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I '1Irl',.r It 1011
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l)fj'~":I'r f\i. '1~;'Ir"IIII'lit Di\'ision
F \\ 1)\\,'" 1\1.,,," 1,...1 IIri"l( Co.. Inc.
1';l1i,-:pll hll.:I.rlluwnl Divi~ion
))i,'/r, ,.-I, SllIn.!"...! CorporatIOn
r:rd('o Enl!ir1t'(~rinp: ("nrpnrnl inn
Fl~dll'r & Pnrll'r CllfllIHlIIV
Flo\\' Corpora' inti '
TII" Foxhl)rn Cnmp"nv
t:1 1IIIIIn In~t,rl1f1H'nt rnmpany
c, ,,,,:01 1\1"t:o) Work" J""
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\:1/1 'lI,d t';II\ 1111111111 ntal IrlslnIOH'nl:--,
1111
~,"I"" Ii hi '1'111111'111, I.:Ihol'!t!orl(,s, Inc,
Ht,:-. :tl'l II ,\PI,I1:II1I'" (:IIllIpIlFl\'
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1\,.I1I'1'J -11:\\\ t '01/111",,", ('I'IIIP:1IIV
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n:l('h:i",.!, hH. ,; ~1:tI [nst,rum(!nL
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Cnrlt-r ,tV l.', 11\'
1'. I\' 1 .\'.1"1' 1\ ,,,,,i:,\'I.lInn~ Co., Inc.
E'''HIII1 111:,!rllnll Jlt IJivlsmn
l)il'!I"lI'il SIJttJdunl Corporation
]I:tSIIIl~"-II:,,,I"I, In"
E. V"IJlOIl IIJI! LIII'!)1 poralni
T\1, )];1111 11I~,lrllllll'nl ('o,npnny
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'!'IIII,i ,'il'II:-l1r a:-IlI1:I'I(1 CompaDY
Mad" "d.t ~I, \IIII'd Comp9.uy Inc..
N(,t",'n, l':ngl1uTJ'inl~
PholflJ" ;1 ( !lnqlallY, Inc,
i'h(jtolll;~"iI1n, I tit.
)<1,1111111" 1/1:\/1 !IIdl'ld, Munufncturing
(;(IJI;,'!':IIIII:j
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HOI1'" ":I, I J nr!Ij:;I noli J"illcrB Co,
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H/lliI'rl J( V~lIglJ ("",Inc.
Meteorofogicallnstruments
Alrflo\\' ]11 l"),IIHII"nl', 1(~anfldl1) Ltd.
AII' S;II\ll'lln.~ ,"'n ',It IIJ:", Jrtf~,
Ald,u 1'.1"'11'>111" ,\. 1I1I1,u18l' HI'cordiu!;
J':qIIlIHIH Iii ('l.mp:u1Y, Jnc.
A 1,,01 J 11';11 'lftll'lll I :fllUpany
Alllti!IIIIII,d 1<1\\ 11,)lll1ll'lIll,1 ~}'8tf'm9t Inc.
HarlH':-: 1',n~I,IiIl" I I III!: C 'ollapau.)'
Ik(:ku'HII IIISIJ"lJlIIIIIl.'''1 Inc,
Ud(orlln.-;ln1lIlf'nL Company
Tit/' Ikn:JI\ Cedi Irallon
Cilldl(1I1 1':1, (III Pili'"
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ChnH't Jw.,ll'Illin 111:->. Jnc,
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J! "I t 'flip/nil: Ion
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J >.\ ",rod) lI:lllli"~, I'I( .
1"I"nll .1",,, 1".,lrllrn,."ts Incorporated
1"lrll-h d 1".I,,"lnal ",str'ms Division
J,,,"d, & "",t,lll:' ('I)i~lpllny
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J\1~'lrClI,i"4 '\'~";Pf'IUIt'~, Inc,
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~II~ ('lIlp'oIlIlllIlI
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Lit.ton HYRtf'me Inc.
I':nvironml'ntal Rellearch Corporation
Part.id,' T,'chnology, Inc.
A
Ahllrt EngineeriDl Ltd,
ti4 Vaugha.n Road
Toronto 4, Ontario, Canada
Acr' Gl88S Incorporated
P.O. Box 688
Vineland. New Jcr8l'Y 08360
AER Corporation
Ramsey, New Jersey 07446
Aerodyne Development Corporation
5ORO WarrcnsvilJe Center Road
Clcvl'land, Ohio 44137
A,'rodync Machinery Corporation
fi330 IlIdu.t.ri,,1 Drive
Hopkins, Minn. 65343
Al'nmutronir. Division
Philcn-Ford Corporation
N,'wport IIPnch, Cahf 92&10
'\,'ro VU(' Corporution
",) Box 448
T....". N,.w York 12180
Alld",t.,.d IIICill,'",'or Corporal.ion
'lona Hllllllydnie
F"rnllll~I''';. M ietlll('''' 41{024
1'111' A!I:,.t Mnlillfllcl.uring Co.
1\", 248
\oInllll, Mic'hiKIIII 49221
Air.'ael.tlr Corporation
271 Mad,soll AVI'lIue
I'\,.y York, K"w York 10011\
.~,,:I . :. ",'lopnlf'lIts (Canada) Ltd.
:H 1 oJ ,." k ,rk Hoad
1(,..11"'01101 IIJlI. ()lItarlll, Canada
\"k"m.lllf'.
I' I) IIn, 20:1
("11:1111"[1'1' HOHe!
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.\ II !\1"(\lt(lrlt1~1 Inc.
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1(0' "I (hk, M,,'., 41iOO7
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701 1'!lli~II(I,' AV('HUf' ' .
I, II,.I"",ood (:I1IT", Nf'''' .lcr""y 07632
IIII' .~" Pr..l"'III.l'r Company
II ""'1',11,.. N,.w York 14R9.~
\ II ;--;ampllllK SVMtj'lJ1~r. Inc.
.\(1 N III"'''' Ho"d
\ "1I~fT'.. N, w Y",k 10710
\Ir :~n,I('IH:q f)IVJ:-'lOn
1,llrll'llIt!IJ.<.,tri".'-i,In(",
1)111 C'hr:11l;1' PlnC"f>
h:II.IIIIII/II\, "II'hi~~;,,\ 1f}OOI
Dyn.mometera
Centri-Spray Corporation
MANUFACTURERS
Alden Elrctronic & ImpIIlsc Recording
Equipment Co.. Inc.
Waehington Street.
Westhoro, MII&'IIlchusntts 01/181
Alkur Engineering Corporation
P.O. Box 396
Lodi, Wisconein 6356Ii
Alnof Instrument Company, Div. of
IlIinoi~ Testing Laboratoriee
420 N. La Salle Street
Chicago, Illinois 60610
American Air Filter Co., Inc.
215 Central Avenue
Louisville, KI'ntllcky 40208
Ameriean Blow IJipe Co. Inc.
3459-51 W. Crnnak Road
Chioago, Illinois 60623
American Felt Compan)'
A ("CO Filter Products Division
101 Glcnville Road
Glenvillc, Connecticut 06830
American Incmerator Corporation
041 Ll.xington A vnnue
N,.w York, NO'w York 10022
American Insl.rllmf'llt"'eompany, Ino.
11030 GO'ur~il~ A v,'nllc
Silver SpnoK, Marylalld 20910
Am..rirttn-.r"hooon Compllctor Co., Ino.
245 F'r('linghuY8en Avenue
N..wark. N. J. 07114
Anlt'ricsn Meter Cuntrol9
A SlIbiiidi"ry of Thl' Singer Co.
IJ!iOO I'hilmolli. Av,'nlle
l' O.Jlox 11600
Philltdl'lphia, I'll. 19116
American Stnndnrel
Indllstrial Pr"durt.R n"pnrt.mrnl.
DPt.rnil., Micl"J(1I1I 48:~12
A mf',;""n V all Tongf'C"1I CnrporatlOn
:J.\3;. !"vlII!':sl.on Av,'nll"
C:ol'lInhIlR. Oh,,, 4:1227
AMF Fond ~I'n 1("- I>lvlHion
1'11l;II." HOl1d
F.Rs,'x, Cnll"",'I.....I. (111420
AlIlIlyticlLll.",rlllTo,nt Development Ino.
21iO Soulh Frnllklin Street
W"ql. Clo'"In, 1'1\ 19380
Andf'r8on S.11I1"lj'l~ ,\- (~nn"lIltinR Ai"rvicr
1074 .\,,1, A", '"''
I'rovo, (1I.IhH4"1I1
An f.ipol COl'p"rIll.1on
I' O. Box 601
Galpsburl(. IliinoiA 61401
Applied 1I,'s,'arch !'al.orato''It'a
3717 Park 1'1,"",
(:I<-od,",,'. (':.liforni:t 91208
Chromal!oy American Corporation
Clayton Manufacturing Company
Sun Electric Corporation
Applied Science Division
Litton 8Y8tems Inc.
2003 Eaet Hennf!pin '>venue
Minneapolie, Minnesota. 115413
Arco Industries Corp.
12JSIiO Beech Daly Road
Detroit, Michigan 48239
Al'Ko PiaI!tic Producte Company
27411 TennYlOn Road
Cleveland, Ohio 44104
Atlantio Ultraviolet Corporation
24-10 40th Avenue
Long IIIland City, New York 11101
AtlaB Electric Device! Company
4114 North Ravenswood Avenue
Chicago, Illinois 606Ii7
Automated Environmental Sylltema, Inc.
1311 Cro_aye Park Driye
Woodbury, Long leland, N. Y. 11'797
Auto Pak Company
P.O, Box 378
4908 Lawrence Street
Bladeuaburg, Maryland 20710
B
The Babcock eft Wilcox Company
Barberton, Ohio ..203
Bacharach Industrial I netrumen I.
Company
200 N. Braddock Avcnue
Pittsburgh, Pennsylvania 162011
Bailey Meter Company
29801 Euclid Avenue
Wickliffe, Ohio 44092
Baird-Atomic Inc.
Atomic eft Lab Instrument Sal('8
33 Universily Road
Cambridg", M88Saehusetts 02138
Barber-Colman Compllny
ChromlLtography Products
1300 Rock Street
Rockford, Illinois 61101
The Barber Manufscturinj( Company
22901 Aurora Rd.
P.O. Box 217
B..dford Hta., Ohio 44014
B. B. Barefoot & AA8ociRtl'8, Inc.
POAI, Office Box 274
Monror.vill... P,'nnH)'lvnnll\ 111146
Rsrnl'bcy-Chcn"y
CRl!llady & Eighth Avo-nnes
ColumbllR, Ohio 43219
B.\rne9 Enginp,'rllljl; Company
30 Commerce Road
Stamford, Cono"clirut. 06902
-------
Rarrin(l:pr Hes,'ar..h Ltd.
:1114 Carlingvi..w DriYo'
Ikx,i»I." OntA,n", C»nncla
'I:1n.1' nlow..r ('oml'all~'
\I!I77lh W,w, N.K
!\I"""'''I'"I;». Mill'H'~nla IiM:\2
lIaH" ('llI'mi..als
S4!i lIalln/l Bmldinlt
('I,.v,.I:ond. Ohio ""11"
IIIIU80.h & Lomh
:~I~"IiI! 1\'\118"'\ Sin',,\.
I(o..l",st.,'r, N,.w York 141102
Ik..k""I1~ lost.rumen'", III,'.
!'ro"'.''''' InstrlllJII'ut.s Division
2,tO() lIarhor BOlllevllr<1
FIIII,'rloo, (;aliforniu ()~4
1\""0 En~in"('rin~ Company
1:112 HOllle 8
(:I,'n,llIlw, P"nu~ylvauia 15116
11,011'0 I'ollulion Cont.rol Curporation
tOO 1','u..s\'lvanlll Avenu..
!'alrrsnll. ':-/..w J,'rSl'.I'075011
II, !furl Inslrun",..t. Company
Fllllr N. C,'nlral Avpn\ll'
11:111111"""', M"r\'lRnd 21202
I\,'rni:-l COl11pflUY, Inc.
I' n. BIIX :1758
:'1. I.ol.is. :\li"~"1Ifi 6:\12'.!
Tht' iii lid,,; Corporal inn
FII\'irolll1lf'utnJ Srif'lu'(' Dwi~ion
1400 T;, \'lor A venue
f\.tlI.'",,;ro' ,TIIW~OIl), :vJarrlalld 21204
H.'ndix (:nrpoflltilln
I'rort's..... InslrlllJlI'nts Division
1(11'1<'('1' 1'1,.. W,'sl Vir~iui" 24!)70
HI rJ..I.I.,y lll!o:frl1l1ll'lIls Corporatiun
Iii!) PO\\ 111 :--iln'!.t
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!',""I,I",loI. '1II'hi~,," 4!j()7~
Hr, ...111\"1' "";"'p'lratnr Cn,
( (1101111011\\', :1111. nlldding
P:II~ hUff'h. 1', 1111-'" 1\':1111:1 1!".~2:!
ITI Hn"'H.1 t ~ofllpall\'
\\ 111.1'11\111', ('11111,1"";"11100720
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BIIIY"I.. 1'01'1(1' ('ompall.\'
.I!"I llro'Hhv:I\'
BIIIT"I", NI'": York 14204
Bllrllllt! III~I rllllu'nl (:ompany
,'n. .!lox 2!IS
('1,"''':111). N,.\\' .I,'rs,',\' 0711211
1I1I1'II-Zol. III".
:1'12.1 I.ollislllnll Card..
Milllll'al'oli~. M,nrll',oln55426
c
C"lihrul,'d l"sl.lu'l)('nl.;, Inc.
17 W ,st. (j01" Slre'l'l.
!II"w York, 1\. Y. 10023
Tlu' ('al hUllilldulil l'IIIII(IHIIY
II,dlulild\ ('tIIIIIOll)ivI0i4IH
1'. (I. lI"x 1:!4i!I
hIlO'VIII,', To',""",,,,, :171101
(:a...lloll Jt:1..ctroni"R
A UII,I of Ul'u,'ml Signal Corporat.ion
LOllg Island Expr,.ssway
Wu".lbur.v, N"w York 11797
Ow.!i,,,, III... ,.1' Corpora lion
POBox b2:,
(:n'l'lIsb(\rll, r\ IIrt h Carolina 27402
(:arparl C""POrH"OIi
:.!I~I v.'" Lxc""nlt. SIr,','t.
(h,u",,". 1\1 iclt il(a II 41181\7
Cart., r-Oay Compall.v
(;,,!i IlIl.h A 1"1'1111". :'\ .1'"
\Iinr"'a,,olls. 1\lillll"'o':\ 55418
CarlOS Ch,'III)l:1I1 Company, Inc.
1:17!i Eight.h 8t.r..et
L" Sail,', IIhn,,1S (jlanl
Cal :dl' I it: I'r"dll"" IlIlt-rnat.ionnl Inc.
I'll. I\ox 3n
:'21 Mill Vall"I' I("art
!':daI i,..., IlIill;"s (j00/i7
TI... ("'Ikllll' Cldupan\'
110 SI...ld"lI I("ad
II, r"a, oh,,, 11017
(~I III n-Spray (:nrpnral ion
:1!M)o1 S..h""I,.,."ft 1I""rt
1,1\ otl lit , Mi,.I,lc:.., ,1~1;~)
("'1'11111 II 1111111' 1;11111' (~n
201:0> S,,,,,h :0.1. '" ";'r,':
L,,, AliI(' I,'" (',d,rol'lli" !"MI07
('ll1'llIu'al CUII~lrl1f'fioll COlupnny
11,.1111111111 ('IHlln,II)lvi"ifln
:I:!n 1'",'1. A""IIII.'
", II' Yorl...'\ V.IIIO:?2
('111'11'" "I H"',, ";YSt."III~, I"".
(I.f..,d. 1', .It'''' 1""IIill 1'1:111:1
(~hI4:WII \trJ.'dl'r(~1I
;172:1 \\ f :",".111",,1"':1101
1\11,"1\1., 1.1. Ilh""I~ t;U!d:~
('1.111111..111.\ .\111' 111':111 (~otru)rullnn
1.'.I.;f~ I '1,.lIln"l :\ \ 1'1111.'
111.\ 11.,",,, (' Ildl'IIII.' !tCY1:.H
Clayton Manufact.uring Company
Post. Ofli,'p Box 550
\<;1 Mon'.', Cnhfornin 91734
('kv""nd Controls, Inc.
I I II Hrookpark nond
Ckvf'lnnd, Ohio 441011
Climntrnni('" Corp.
1:\24 Mo.tor Parkway
HlluppnulI:(', Nl'w York 11787
ClimP.t. Inst.mmrnu, 11\('.
570 Sn" Xnvil'r Ave",\('
Sunnyvoll', Cnlifornin 94086
ConAt. Manufact.uring & Supply C'"ompany
nox 71
Liv..rmorr, California 94551
Combust.ion En~iD('ering, Inc.
1000 Prosper.\. Hill Road
Windsor, Connecticut 00095
Comhuotion Equipment Associates, Inc.
120 Park Avcnup
New York, N. Y. 10017
Compact Air Samplers
825 Belmonti' Pnrk North
Daylon, Ohio 45405
Compaclor Corpornt.ion
370 l.exingt.on Avenue
New York, N. Y. 10017
Comlro, In('.
Nort.h WaIl's, I'l'ltnsylvania 19464
Con""ljdall-d Elect.rodynamics
Corporation
360 Sicrra Madre Villa
Pasndena, Cnlifornia 91109
Const.rucljon PI'
-------
D
The Dacar Chemical Products Company
Dacar Chemical Building
McCartney at Wabash Street
Weat End, Pittsburgh, Pt>nnsylvania
15220
Davis Instruments
Division of" Automatic" Sprinkler
Corporation of AmNira
cl7 Halleck Street
N(wark, Nl'W Jt>rsey 07104
Delllvlln MnnufactuJ Ing Company
811 FOllrth Str..et
WestJ)es Moines, Iowa 50265
O..lphi Indllstrles
11672 M"Bean Drive
I'~l MontA', California 9173\
J)",pal.rh Ovell Company
p.o, Box \320
Minneapolis, Minnesota 55440
1\1 II, Detrick Company
111 West Wnahin!(ton Street
<.'hi(':\/:o, Ilhnoi. 60602
Det roi I. Stoker Company
\510 K First Stred
Monro.', Mirhi![an 4816\
I J,,\'(,o )',QJ(lnf','ring Incorporated
Fnirf., 1<1, Essex County, New Jersey
117006
j)"V,Jhiss Company
300 Philhps A venlle
Tol,'do, Ohio 4360\
J )1:I!I1ond PCJ\\I'f Spl ually Corp
:112 WI,",,,,,.' j\IIiletill!,:
,,'W OIl"IonS, [,"IIisllln.. 70130
1)1-:1 Instrunwnt,'i. Inc.
27111 :-;"lIlh "nUtleta\' Stn'I't
:-;:lIlln AlltI, <'nhf"rnln 112705
I )11111'111111111 In~lnlllll'nl8 Company
\ '"'llt!d IU!'IlrulIH'ntR Division
I II: I Inell' \'io::tR Avpoue
~1"IIIII'''11 V",w, Ca\af !14040
I J'llllng,'r (~(lrJH,1rnflnn
li!1< 111 sIt I, \1. \\ \'olk ).160;\
! ),1111,,\ HI'I!>'; ('II
I:I\WIII ~1,J"s """"10'
('II'I'"IIITld, Uh,o HIU5
I I"l r Plt\ .'f 111('
77 11:1 \', JrH":l'r LfLnt\
o,l:"lIfo"l, ('oll11rrlll'lIt 06001
/)" ,""I' M"lIs"I'I"rnl'nl DIvision
!~WI W.'st. MOllnt Stn'l'!
C'''ITI''rsvdlr, IndiAna 1733\
TIll' I )uro'l ('ornpnll\
1171';11,,1 S"I'O'''! St,
~h'\I"";I, LOTlI( ""'n<1, N"w York 11[>01
f)r;",,,.J)oyJr. Co.
fn,I\,,1 1 illl EI/luprrlt'nl P,v,
"(-III 1'",'01" "\'('111'"
l'i'I.'''"rl(\a, 1','nn.'\'I\'"nla Ifi:.!:J:!
DualI Industries Inc.
700 South McMilIsn Street
OW0980, Michill(Rn 48867
Du Pont Company
Textile Fibel'8 Department
Centre Road Building
Wilmington, Delaware 198118
E. I. du Pont de Nemoul'801: Co. (Inc.)
Inst.mments Prodne.ts Division
Wilmington, Delaware 111898
1>lIst Con trol ('AI,
1200 Brookpark Road
CJ..veland, Ohio 44109
Dusl.ex Division
American Precision Industries, Inc.
2777IWalden Avenue
Buffalo, New York 14225
DlIst Supprell8ion Inc.
P,O, Box 67
Lake Orion, Michigan f803/I
F, W. Dwy~r Manufaoturing Company,
Inc.
P.O, Box 373
Michigan C.ty. Indiana."83eO
J)ynasciences Corporlltion
Instrument 'ystems .i.>iviaion
0001 Canol(a Avenlle
Chatsworth, California 91311
E
Eclipse Fuel }o~nj!:ineering Company
1100 Buchanan Street
Rockford, Illinois 61101
}O;l"ct,ronic A...iatancc Corporation
:.!I),Undge A,,,nue
R..d Rank, New JNsey 0770\
1';I"et,mnice CorporRtion of America
()nc MI'lTIorial Drive
('lImhrlll!':I', M808AOhllll<'l.I8 02\42
I<:lIiHon ITistrument Divi8lon
»,ctNirh Hlnridard Corporation
1',(1, Jlox OO-Orllnany
Dracco Produc18
124 Bri.iR'p. Street
CatllMu'lua, Penney\vania 18032
G
Garden City Fan 01: Blower Company
883 N. EiR'hth Street
NiJ.'s, Mi,'hi"'Rn 49120
Gardner A880ciatl's, Inc,
3643 Cannan Road .
Schenectady, New York 12303
Gut. Manufaclurin. Corporation
P.O, Dox 117
B.mton Harbor. Mirhip;an 49022
-------
(',1"""1 1n~ IIridtT,.town HO:le!
('I,., , " (11,,0 l.il)(Y!
t ;b...., 1111111\':111011' lilt,
I' C) II.., 1\ '
'\.1.1""", ""." Y...." I,ISOI
(:10111' "111:11\\ C'llrpnr:llln1\
1\00 (,!i,,'on Str,.,'t
11,,11' .I". N,.w Yor" 112.\0
.Jn~('rh <;"d"1" frwllwfntor.-t
2.1S:t Cr"j,,,lr-nr A\'I'IIIH'
Elk (:,.."..' Vil1:1p,... Illinni" 60007
(;onloll-Piatt, Iw'
I' (J. Box 61;0
\\,i"ri..I.!. K:II":ls H71rlii
(:rITIl 10'\11'1 El'onOlnizt'r Con1p:lllv
:\ I ),vi,io" or Eeol:lire Inc.
1I"R,'un, N,.w Yurk 12508
(;ritTi" & Co.
.'iOO .!kr~l11nn A v.'nul'
I' t). lIox 21:1!Mi
1.I)"i,,'il1,.. 1\ \'. 4n221
H
1Iarl""1)
ftlHh and "roodlllilli Av"t\lII'
I'hi"'d,",phi". I'll. 1!1143
1 1,..;1 '''I':,-II:I)'d,,,t., Inc.
't'W~tHllh A\'C'nUt~
1/111111'1,,". "irp,;nin 2;\:IH\)
Ilf'III'nl('I'~" EquipllH'nt Coq1oTation
1~'I()1 Eh"w..".! A v..nUe
('In,.hm.!, ()h,o 41111
II, "". (:old"milh.1< CompRny
'1)1\ !S,on or B"rIml':lon Indust.ries
14t,u Bro,lIiwHY
:.;, II' Y"Ih. ,""w Y..rk 10018
K V,'mo" IT:!I In"ofJIo,rl\ted
I' () II.., J 12.!S
:-;:". I'mll";"''', ('ahfol'(lill 94114
Illrl ('()mhll~tion EI,~ilH"'rs
~I:n :'fill,h Mapl,. Av('ntit'
:' ["nlplwll.., C..hf"rnin !)O(HO
H"II,','w..1I
;li47 Fnllr!h .\\'1'11\11' South
~'1 illllf':\polis. ~1Innl.~tll a [.attOoS
"""""fI "",IS. I Ul'.
1'1) II", )'1(1:1:'
""""'..n. T..xns 77024
Jill' t r...1:IIHlbdurilll!: Cnrl'orarioll
V"",.. re":I.!
\\'-'I''''',I\I:t,,'.027'MI
t I \ 11.1 ('01111111'111111 ~ '.1J)1nrllfiun
'Iotdll ',' ~I\f I 1'1 ~plln~':i UI""I
~ '1\1',1:" ~'I,I"W', (':dlfIlIUJ,1 tMMi;U
11\'p:rod.l'IIRmics, Inc,
!14f1 R. hm RORe!
:-;ilv,'r Spl'inl!:, Mllrylnnd 20910
IBW-!\l:tl'lill In,'i'lI'mtor Group
~ )\'11 Ton ( 'nrpornl ion
Ellsi. HII'"udshllr~, Penns.vlvnnin 18301
I I' c. I ".!lIsll'i", 1111'.
IiS7 H. """,
1','lre,;I. Mirlll~l\n 'IH217
III': ,hul'l." I';"s Iuc.
(;"111 rId 1'10\\11'1" Oivitiiol1
2S2(1 N. I',,"'ski HOlld
(:1''''1111:;', IlIi"oi" (,0611
I ndll'" 1'11\1 Blow Pip,' (;"rnpan.\'
2700 Jnekson A v"nlU'
M"I1II''';'' '1'""",.",,,,,. ~RJM
1."I"'.'ri,,1 C'IInh,,"fion In".
4.J.17 N. ('"kl""d A""lIu,'
l\1il\\ ""I""., W'''''O''S;'' 53211
Inll".,l.r;"II'I",II" Fnhri,.ntors, Inl'.
":ndi,'ott SII'I'p(
Norwood. MassllchuseUs 02062
I nformntion Instrument.s Incorporated
,\111' Arbor. Miphi~an 48103
l"rm-H. II Ine!II,9trial Rystl'ms Division
fh"'rll1\ Ci)r",nralion
1~2:, i\I 1,01,01,. I{oad
(~h, ~hln'. ('jllili. Of..110
I II 1"I'""t.innnlll.\'Iu.f iI's (;orpomt ion
1 Tllfl.SI.I'I'd
1'.0. lIox H:17
Sn. )\;orl\'I\)I.. COIIII' etie"t 00.'1[>6
Inl....II:llJoIIILl P.p~' Hno Cf'fnnlir.R
Corpofll j inn
( '( Irro.'iion Con t rnl Pi \t iaiun
2f.o f'hl'rry Rill .!toRd
1'1I"'I'p"n.\'. N,.w .11'''''''.\' 07n54
IIII....fr Slrept,
Prinl',"on, N,.\\' .Jersf'.V 08540
J
.Iarrdl-A"h ..!hv;,ioll
FISI"'r Sei..nf,(ic Company
:t~H1 J '''I('oln :--:1 rl'~t
WIII'I,:'I". l\1:\.'''n('I'''SI'It.~ 02154
.1,,1, ",.-1\1:0 n 1'1 III' Proe!UCt.9 (;orp.
"P. 110" 1:,!1
1\111"\'111<-, N,.w .I.'r5"Y 088:1!i
Till' .loionson-Ml\reh Corpomlinn
:lOIS Mnrk"1 Sfn,..1.
"Ioi"'oI,.II'Ioi". Pf'nnAl'lvl\lIin 1!1I04
K
hirk alld /11'10' 1\1"""f:II'I"I'II'1I: Un.
:1120 1'011'1 r S'I"''''
CIr1f'UHIIIII, Olli" .1[)2UH
(; A f\ II t...kr f '1IIIIp~ln'
I !(. (;,,, 1:111 :--:1 H'I.f
'\"W:Ir1" :\1 \\ .1"1'''-' \ (1710')
Maurice A. KniRht Company
171 Kellv St,rl'et
Akron. Ohio 44309
Koch Enl!;in..ering Company, Ine,
41 EBst. 42nd Street '
New York, N. Y. 10017
Koppers Company, Inc.
Inrl"st.rin.1 GRS Cleaning Department
200 ReoLi Rtrl'r.t
BI\Himore, Ml\ryland 21203
K rf.hs Enginl'f'rR
12011 Chrysl,'r Drive
Menlo Park. California 91005
l
J ,fLh"ralory Equipment Corp.
SI.. .IoSl'ph, Michl!!Rn 40086
],,'('kl'nhy Company
27451Hh Avl'. S.W. HArhor IRland
!:;"ILtt1e, Washington 118134
Ll'eds & Norl,hrup Compa.ny
Sumneytown Pike
North Wales, Pa. 19454
Leigh Instrument.s Limited
115 Emily Street
Carleton Place
Ontario, Canada
Lit.lon Sysl.,'ms, Inc.
3M II:\w80n Drive
(;"III"rillo, C'llifornia 93010
Los Ang..Jes Scientific Instrument
CornplLny
2451 Ihvnrside Drive
1.0" Angeles, California 90039
M
MRC Leod &: Stewart Co. Inc.
43 'Rome St,
Farmingdale, L.I., N. Y. 11735
R. C Mahon Company
6:'65 EIIRI. 8 Mile Roa.d
D.,troit" Michigan 48234
Marbon Division
Hllr~-Wamer Corporation
',V",I,ingt.oD, W.'st Virginia 26181
MfI." f),'v..lopmcnt Company
2212 Twelfth Street
Dav""I,"rt, Iowa 52803
Matheson Gas Prodnct.s
!l32 Paterson Plank Road
Ellst Ruthl'fford, N. Y. 07073
Mnxon Premix Burner Co.. Inc.
2UI K 181h St.rN.t
Mlln..ie, lne!inna 47302
Mdnnis Equipment LimitPe!
2,.00 Central Avenup
Windsor 111. Onlnrio, CAnada
1\1.. M "'nn 1-:1..'" roni,'. Corporation
r.lilfll',"1' 81""'1
1I1I1I!l'iIIlYl T('x'l~ 770:lfi
-------
M..Naulin locinerators, Inc.
P.O Box 634
Blilln, Wisconsin 63007
Medi-Comp Research &: DevelopD
Corporation
135 South Main Street
Salt Lake City, Utah 84111
M,,!oy LaboratorieB, Inc.
fnstruments and Systems Div.
6631 Iron Place
Springfield, Virginia 22151
M..Jpar Division
American Standsrd, Inc.
7700 Arl1R~ton Boule\'ard
Falls Church, VirgiRla 22046
M"nltrII, MlIlISachusett.s 02067
1\II'I",'rol,,~.\' Hl's..arch, Inc.
.W4 W. Woouhury Rd.
AII"d""'",l'alif 91001
!\.1, !IUIIU'c A.s.-':OClflfl'S, Inc.
:t!01 I'orl", Vnve
1';1\.. ,\II", ('1l11fornill 94304
:\1, l'I,'r 11l"lnlllll'nt Curporation
'!() \.IBW\lI :--:tn'd
PIIII! f'/\l11, \.'w .Tf'r,,('~' 08f>40
1\ 111. W 1I1",,'r "lid ";ons, Ine
"'~h I I':lmwood A \,rDUP
~k"kll', 1 1 11,1> liS 60076
~II( I' 1411,'1\111':11 ~p4'('lItitiI'B Company
:\11."';( '( I ~'Jf'nlltlt'
'''2.-, I. a"I,I"",. 1III(I,way
1\ ,k, I",., C"lilorn1ll9471O
,\1,01 ('",,,,,,. III Ml'tnl I'rod"l'I1I Cnrnplt.,,V
..'; I'I~ 0: (; II I II \' If \\ :\ ,'PI11 II'
('!,It .L~'!I. 11111101" liO(; 1,1
\11" Ii' \1 'II,
1)1 \ 1,1'111 !If TIH' :-;Jlr J... ('prpl)! ~\lIOll
It) ('11:1111;1111 ril' ld
-'111111\1)1 ,\, \\ 111"'1 \ O'inOI
:\111 \1\ l\t,!IIHI:I, ~\lIIIIt:.l'onHIt:IIIOH
(II ('I' "'1111 -":'I"!
1\,,,,,1,1,... ,," Yo,k 1J2O/j
\ III! 1,11111:--1, I! ", hlL'
,(HII) !:I J III lin:HJ
'-,1'1' \, 11111 1'111\>':11111:1
71H)!;
\111111\1111 ('''qHJra!10n
1/,1" /(",,1
I~, .11,,,01 1\1 "-,,,.1>,,,, lis 017:10
Mil (1:11' ,,",, ~!!'rn:i
:!111 \1qrn,,,; ,'\' ('FIlII
f ,~, I I " ): 11'~"
Mine Safety ApplianceB Company
201 North BrBddock Avenue
Pittsburgh, Pennsylvania 16208
Modem Dust nag Co., Inc.
132 E. Railroad AveDue
W. Haverstraw, New York 10993
Monarch Manufacturing Works, Inc.
2501 E. Ontario Street
Philadelphia, Pennsylvania 19134
Monitor Labs
10451 Roselle Stre~t.
Slln Die!l;o, California 92121
Morse Boulll<'T Division of
Hagan Industries, Inc.
53-00 97th Place
Corona, Nf'w York 11368
Motorola, Inc.
1120 Connf'eliclIt :\v('nuc, N.W.
Sui.... 1120
Washin~ton, D. C. 20036
Mount Vcmon Mills, Inc.
201 East. BAltimore Street
Baltimore, Maryland 21202
N
NA DUSTCO, Inc. IJiv. of National
Blow Pipe and Mfg. Co., IDc.
1641 Poland Avenue
P.O Box 52079
New Orl,"UlS, La 70150
Nat.lOnal Alroil Bumer Company
1284 }<;a..qt Sedgley Avenue
Philad"lphia, P('nrJ8ylvania 19134
~!Ll.ion,.d Du~1 ColI,'cl.or Corporation
!,f);!3 ~"'lh Lawl,'r
;'Koki.., IIlillois 60076
l\ :<1'011:01 1':nvlrJ>nml>otal Instruments,
JII".
P.O. Box !:i'I<)
""II Hi",'r. Jl.i:1"sa,'hos.-t13 02722
Nat.wn:d FlIl"r lVI, dia. CorporatioD
171'1 fllxw"11 A\'enue
New Hn\'('II, Connecticut 06514
N ;11 iOIJ:\IIII1I1l( rutol ~orporHt.ion
I!)OO ~(llIlh Wf'KII,1't1 AVf:nllf'
('h"'l\l(o, 111'"0'" 6OfI~
"~II'llIlIuIIIlMlnlll',,'~~1 1./lhorJtt,orip8 Inc
I~;m() 1'III'khwn I iri,,!' I'
1t"'L,ill" 1\111"1,,",, 211111\2
Nt 1.('1"0 E"glll('~'11I1~
11tr1 ('hallolln II \'/.'''U''
1t"".I1,', N,.w ."'r'''" 072t)'l
!\ "I\' \' "rk Blown Company
:~!nrl :--;111"" find ~hi.,lds A\'('uuP.
('hll .q.[CI, illmol.'" f)fNilfi
~1,lgilrlf. 1\llIwf'r (~(IIIIpl\n.v
40!) L"xi"~lon !\ v"nue
~('w Y"rk, N. Y. 10017
1'1", '\Torlh IIrn, ,i":ln Manufacturing Co.
4-1"" F""I 71st. SI fI"'!.
: 'I, ' I 1.11111 ()!III) 11111,1")
Norton Company
P.O. Box 350
Akron, Ohio 44309
NUS Corporation
2361 Research Boulevard .
Rockville, MarylaDd 20860
o
Olson Labora.tories Inc.
22805 Michigan A venue
Dearborn, Michigan 48124
Oxy-Catalyst, Inc.
Eut Biddle Stree t
West Chester, PennBylvania 19380
O.one RellCarch and Equipment
Corporation
3840 N. 40th AveDue
Phoenix, Arizona 85019
p
Packard Bell Environmental Sciences
649 LawreDce Drive
Newbury Park, California 91320
Packard Instrument Company, Inc.
2200 Warrensville Road
Downers Grove, Ill. 60515
Particle Technolol!Y, Inc.
734 North Pustoria Avenue
Sunnyvale, California 94086
Pcabody Engineering Corporation
232 Madison A venue
New York, N. Y. 10016
1'<'crl,'s8 Inst.rument Co., lnc,
512 Main Street
Wcstbury, Nf.'w York 11590
The Perkin-Elmer Corporation
Norwalk. Connf'cticut 06852
Philips Electronic Instruments
750 South Fulton Avenuc
Mount Vernon, New York 10550
Photobell Company, Inc.
12 East 22nd Stref't
Npw York, N. Y. 10010
Photomalion,lo,'.
Box 460
Mountltin Vil'w. California 94040
Pil t.Hburl(h A, II\'Atl'd CArhon Division
CIlI~"D Corporation
P,O. Box 1346
Pilt.l'lhur!l;h, P"II'I'.\'JI'IInia 15230
Plibrico Company
Ineim'ralor Sales
1800 Kinsbllrv 8trN.t
Chicago. Illinois f\Ofil t
Pollution Monitors, Inc.
722 WI'~t Fullerton Avenuc
Chi.'a~o, Illinois 60614
H. K. Por(,'r Co., Inc.
Marlo Coil Works
7100 GrHnd AVPRlII'
RI. LOllis, M iHHoun 6:\ III
-------
Pro'('ipilair Polllltion Control, Inc.
S1II.s;,b:l'" of Alh'an",' Ro,s Corp.
I' () lI"x 7:!O:!
J,"III(V;"W, TexIL" 7[,(;(11
Pr",'i,;on S('i"ntifi(' Company
:!737 W. CortlRnd Slrp,,1
Chil'n~o, Illinois 60047
Pn'lu'o Dinsion
Pi..kanrls Mlltl1('r ancl CompRny
2000 \Inion COmIl1Nc',' BI1IIdilll(
(,1,,\ ..\11 lid , Oh", 1-1 11~
I'rol'l'ss An;tlvzprs, 1111'.
II.IOII SOli 1 11\\"",1 "'1""'\\'11)'. SlIil,' 100
IIOIISlolI, Tl'xa, 770:11\
Prnt'lor c.~' Sdl\\JlIII.. lu('
SlIhs,di:ln' of S' ~J\1 (.orpnrillltill
jlh Slr,'.'t and Tabor 1(0,1(1
1'llIlad..\"lIi".I'" \!II:!II
Purad 111('.
721 I\illlllllrn(' Driv,'
I1pl"IHI. California 917S6
p.\ 1'0 IndlJslrit'~, luc.
:111 \\' "His.... A \'('11111'
!\I'II,."b. :-';,'W Yurk 11501
R
H" s III"w I'll'" M..nllfllr'urill~ Company
:.!H25 Fifth Stro'et
Be, k,').',\ , C'alifomiR !14710
Hcli"nc,' InstrulIl<'lIl Mllllllfacturing
(~oqll)ral tOn
11:1 La'H'''''''' Stro'l'!
I(,II-k"IlIlIl,'k, Nt.\\. J('\'sey 07601
H 1'.1\1 Illcorp"r,,',.d
~IH)fJ ('"torado A\('H\H'
..... loll I \101111';1, (',dd' !IOll1t
1\. '.1 11\ I. .\!.pIWI1l4' (;(11\1)1;111.\"
HUIII.' S &. Crnll,~I!(,:HI Boat!
\ "'''"1 I'"rk, 1"'1111"'\ 1\ 11111:1 1.-,101
i(''''1I'!.I,-C",I".II, I...,.
I' ~, 11o, 7r,1l
I{Hlllt.! lh,ud" '\1 \\ JIT"!.' OSR05
H, " I un II I'rHdtll'ts Cl\rporallon
1015 1':H~t \\',t..lllnJ,(loll :\"/'JHIf'
\ladl'''lIu, \\ .'wolI:-;in !U7Ul
H'Sllllr," ("lIldl'll. JO(',
Frllnluj!,' HO:III
\\"" IlI/VI'n. e",,", dll",l OC"SIfI
I., 'Idl;', 11)(
bOO :11".11:;<>11 Avellu"
,\,,, Y"rk,:-': Y IIMln
Jill.1.11 r, 1.H'.
:\:I,!!I '1"'1'01111,,1 Drl\'"
~t I'"ul. ~fllllH's()f ~ a!)l:t:;
1:1)1.. rlstltl\\' CUlilrols ('Clrllpftoy
17111 11111'<1 "V"IIUP
'\ld.IlIl}lIcl. \'ir~ln&:' l:t2"''f~
1/,,1,11''''' 1I1,"1I1fa('llI: ill~ ('"",,,any. Tnc.
fl:. ;1 ,r, "h'k J .RO"
\\ Ioft,I....I,,,,k, :'\:1'\9 York 1''!I'I''\
RolS8 EDgiDceriDj1; DivisioD
Midland-Ross CorporatioD
P.O. Box 147
New BnlDswick, New Jersey 08903
Royco IDstrum<,nts, IDc,
141 Jefferson Drive
M('nlo Park, California 94025
Ruemelin Manufacturing Company
3860 North Palmcr Street
Milwauk<'<" Wiscolisin 53212
s
St. Luuis 810w Pipe and Healer Company
H148 North !Ilh Street
Hl. Louill, MillSouri 63160
SRrg('ul-NCV Division
111m 11I.h:stri,~, Inc.
lilO I>"vun Street
I,carD< Y. New Jf'",<,y 07032
Rrl,milll Insl.mm('nt Company
\'0 Box 111
San Carlos. California 94070
Cll1\11k H. .,eI,nl.iblc Company
r 0, Box 100
11011.\',1\1. ' i~un 48442
H<:hut.t.e 1\11<1 KUI'I'ting COlllpl1ny
22:!3 Rtal.f' I/ond
Cornwallis II,'i~h!s
III!('b rOllnly, P,'"nsylvania 19020
S,."./)(:<: Assoeiull's. Ine,
230 Na'sau Sln'l'!
\i",2:\0
I'mll'don,:-':..J 08.'i10
SC'WIH'{' Purllp Curporalion
1-1,11 1"'1'1'\' 1\v,'n",'
(~:t'nd,.". "i,.\\' .I,'r,,'.\' 08104
Sf''''IIC't. ~pf drulII, Inl'.
1'.0. tI", :11"1:1
S:lnta 11:...10:11'11. (:lIlif. !I:lW5
S..it'ntific 01""" Hlowill/( Cn., Tnc.
MIO LRwlldRle
1I""sloll, '1""1\" 7702.1
S"l<'nlifk Indll,lri,'s, T,"'.
Ir, I'nrk St...,.!
Sprin/(fi,'ld, Mas.<:I<'hus,'lIs 01103
1'i,'if'nlifil: Pollu"oll COllI .,1 Curpomtion
.~n(i Fifth AV"II''''
N,'\\' York. N, Y 10036
S~1<'"tifi<' S\'St.'1115 Corporation
101 t<:nst 1I""I;nl('on Driv('
ArI'~di", (':thfornil\ 91006
S.'ol t. /I"sf'a..rh LRhorator1<", Inc
PO. \l1)X II-II
I'bllll',I"IIII\'ill.'. 1', "ns.vh ""ill 181M!)
S('"I r.v Cun (r' ,Is, hI(',
PO II". III;
1',.,,1'1 1/"".1'. N, Y. IO<.Ifi:,
~f'\'f'l ~k,v )':1,.(" I 01111 lOin ('llrl'
~m 11.".1...[,.11..1' 1'1"",
\;,,, Y'"i.. " , "")'10
SF Products Canada Ltd.
4480 Cole de Lif'88e Road
Montreal 9, Quebec, Canada
Silver-Top Manufacturing Company, Inc.
Scientific Apparatus Division
Pulaski Highway
White Marsh, Maryland 21162
W. W, Sly Manufacturing Co,
P.O. Box 6939
ClevelaDd, Ohio 44101
Smoke-Ban Manufacturing, Inc,
711 E. Curtis Street
Post Office Box 4164
Pasadena, Texas 77502
Somerset Industrial Fillers Company
752 I,incoln Boulevard
Middlesex, N. J. 08846
SONAIR, Inc.
8 Bloomfield Avenu"
Pine Brook, New Jersey 07068
Sonic Development Corporation
a Indust.rilLl AVl!nue
Upper HlLddle Hiver, N. J. 07458
Spectrometrics uf Florida, Inc.
P.O, Box 517
PincllllS Park, Florida 33565
Bpra,)! Engineerlng Company
100 Cambrid~e ~tn:et
Burlington, Mass:t('husetts 01803
Spraying Syslems Company
3224A Randolph Street
B..llwood, Illinois 60104
Standurd Huvens Syslems
Glasgow, Missouri 65254
Stans""'" Corporation (formerly
Standard 1'11"1'1 Corp,)
5001 South Boyll'
Los Angf'lcs, Cltlifornil1 90068
Thc Stapl,'x Company
Air Rnmplf'r Dll'ision
777 Fifth Avenuf'
Brnnkl,\'n, Nf'w York 11232
Su,iuen Mftllufacturing Company
29 J<:lIst Halsey Road
Pal'
-------
T
Tailor and Company, Inc.
2403 Slat.e Street
BettRndorf, Iowa 62722
Taylor Ii: Gsskin, Inc.
6440 Mack Avenue
Detroit, Michigan 48207
TechDlcon Indllstrial Systems
A Division of Technicon ID8trumenUl
Corp.
Tarrytown, N "W York 10691
TexlIII Electronics, Inc.
5529 Redfield Street
Dallas, Texas 76235
Thermal Rescarch and Engineerinc
Corporation
Brook Road
Conshohoeken, Pennsylvania 19428
Thl'rmo m..ctron Corporation
I:!fi \o'i"'t A VN1I1e
Walth&nl, Ma88. 02154
Th,'rmo Svstem-, Inc.
Z500 N. Ci,'veland Stmet
::>t. I'slli. Minne80la 66113
Th.,t" SeIlIlOr8, Inc
1015 N"rth Main
Orllnl1;(', Cahforrua 92661
.I T. T""rp.. Company
I' 4) 1\", X!J!19
1I,,",t,,", T..x.... 77033
'1'''"1 Manuilldnring ('A>mpany
11J.lltnnkm Street
:-;t l'all1, MinnpfIOta 55116
l'ol "lOll B.daucI' Company
:\:1 M()IJlII'~1\11 ~'rl.('t
Chf'on. N,.w .J,'rs,'V 07UI3
TH:\C\1H In('
\1I1I1\'II('alln:-;trulJu'liis
,,,"NI Tramr Lillie
'\"S'"I. 1'",,," 711721
11"1 III 1,IIHit.t'd
:t'.!I.\~. I,r'n\\tlrth I)nv('
('IHII.....\ ill,., MIs.sis..~lIIRa. Ontnrio
Tri-Mer Corporation
1400 Monroe Street
OW098O, Michigan 48867
Tri-Pak
7100 Grade Lane
P.O. Box 21070
1A>lIisville. Kentucky 40221
u
UIP Engineered Products Corp.
2020 Est.es Avenue .c.;
Elk Grove Village, Illinoi~ 60007
United Air Sppcialties, Inc,
3633 Cardiff A venuP
Cincinnati, Ohio 46200
Unit.ed 1<;I~ctric Controla Co.
86 Rchool Strept
Wat..rtown. MlIlIsachulICtt8 02172
!Tnil.ed McOl1l Corporation
01181. Collf'ctor Divillion
2400 Fairwood Avenlle
Goillmhus, Ohio 43207
11niled Sellsor and Control Corporation
811-91 Church Str<>et
East Hartford, Connectieul 081011
IInivN8allneiuf'rlltor Corpora lion
21805 Schop-nh"rr Road
Warren, Michigan 48089
UOP Air Corr"dloll Division
Tok"nek" Road
DRri.'n, Conn, 06820
v
Variau A"rojl;rRph
2700 M,l.dwlllJriv('
Walnut ('n,,'k, Cllhlornill 94698
Vl\ri-.~.v~dpIH;:', Inr.
}4~nviron"If'nt.al Hvstf'm8 I)jv.
12% We81 7~ St.r;,.>I.
Clrv..lnnrl, 01.,0 44102
Vir Manufltduring Company
1313 Hllwtho",!'
Minu"spolia. Minneaota 65403
If. .. . .
dny manufacturers have heen It ,led inappropriately or
omitted completely, the error should be brought to the
attention of:
The Editor
Journal at the Air Pollution Control AS~;l)ciation
4400 Fit'I- Avenue
Pltt!'burgh. Pa. 15213
Victore..n Instrument Division
10101 Woodlawn Avenue
Cleveland, Ohio 44104
VirTis Company
Phoenix Precision Instrument Division
Glirdiner, New York 12525
Yon Brand FiltPring Recordel'l
Rhinebeck, N. Y. 12572
w
W &her ElectroniCli Inc.
3000 N. Second Street
Philadelphia, Pennsylvania 19122
Wade Company
A Divillion of Ovitron Corp.
P.O. Box 208
Eut Strourlaburg, Pa. 18301
Rolwrl. H. WI\ger Co., Inc.
PlI88I1ic A vl'nue
Chatham, N. J. 07928
WallaC(, & Tiernan Inc.
25 MaiD Streel.
Belleville, New Jen;l!y 07109
Weat1Jer Measure Corporation
P.O. Box 41267
SBA:ramento, Calif, 95841
We.t.ern Blower Division
Swartwout-Western Inc.
P.O. Bo:l 999
Chehalis, Washington 98632
West.ern Precipitation Division
Joy ManufBA:turing Company
P.O. Box 2744 Terminal Annu
Los Angeles, California 00064
Wheelabrator Corporation
Air Pollution Control Divillion
400 South Byrkit Street
Mishawaka, Indians 46544
W. C. Wiedenmann & Son IDC.
1820-24 Harrison Street
KIUI8&8 City, Mi8l!Ouri 64108
WilkeD8-Anderaon Company
4S26 W, Division Street
Chicago, IIlinni~ 8065]
Witeo Chemical
277 Park A vefllll'
Nf'w York, N Y 10017
y
R. M, Young Company
2801 Aero-Park Drive
Traversc City. Michilltan 49684
z
John Zink Company
4401 ROil tit I'"oria
TIII"~, Okln),olnll 1410.S
-------
Section Twelve
SELECTED PROBLEMS
A. Odors
Industrial Odor ConL...'ol and Its Problems
Industrial illor Control
B. SOx
Control Methods for the Removal of Sulfur Ox~des from Stack Gase~
JUr Pollution: The Control of 802 from Power Stacks
C. SOx
Control of NOx Emissions from Stationary Sources
D. Evaporative Losses
API Bulletin Evaporation Loss in the Petroleum Industry -
Causes and Control
E. Hot Mix Asphalt Plants
Environmental Pollution Control at Hot Mix Asphalt Plants
F. Kraft Plants
Kraft Pulping Process
-------
Chemical
Engineering
Reprinted by special permission from CHEMICAL ENGINEERING,
November 3, 1969. Copyright by McGraw-Hill, Inc., N.Y., N.Y.
., ';~~~;~~:i~~~~{~~." ;;}J<":'::'::'::?" , " ,
AJ".~f~,;~;;I':; '~l.," .~U'''''S-~::t':'.' 8al",':,' ,:',.. .' "
,,\~:? ;I..IU '" ,rl "',, """ '..
~~Qr.:tdrltfol.,'..."
'''~~/''~Ib,' " '
Problems
PA.C.od.3.5.73
./
." .,
,-. . .'
"
AMOS TURK
City College of the City University of New York
Chemical plant odors are more likely than any other
form of pollution to cause community resentment.
Not because odorous materials are dangerous (though
some are) but because odors are so obvious that they
attract immediate public attention.
Elimination of odors is not nearly so straight-
furward as the elimination of particulates, acid fumes
amI the like. For one thing, odors are particularly
diffipult 10 measure; for another, it is extremely difficult
tu decide what levels arc acceptable.
Gcnerully, the discharge of odorous matter to the
atmosphere from a chemical process can he controlled
hy (0) modlfylnp; the process so as to reduce the pro-
duction of odorous matter, (b) u,~lng a device to
reduce the amount of odorant at the point of emission,
(c) dispersing the emitted matter to a greater extent
so that it is less concentrated by the time It reaches
allY puint where there are people to smell ft, or (d)
adding other odorants to the discharge 50 that the
resultant odor becomes less objectionable, 1. 2, 8
In practice, the goal of odor abatement is often
elusive, expensive, or both. The equipment may seem
to work, the calculations may seem rational, but the
-------
-----_._--~-
B
II
II
, Ie
I 1
I I
: 1'1\
, .
I h
1:1
I
A
-~
/(iP~D~\,i,
/"~~,' ,/ :v~~}\.;,~(;~.
~I.:.~ ,.2: ,.~, (:.,\<, .~~~
':8'.- ." '\:: tI' "::, .,~ . ,~.~(,(.r ..~
"it-'" " \ '" \' ""." /
_\\~", ~~:!~:"i.\j '~J;~~
~~.,. ,II'
--
c
---~.~---
(,()III[>Llil1ts nmtillll('. Oecasionally, the (,(lIlIl'l,tints ge:
1'1 "II 11'"'" aftcr tll!' a"al('lllI'l1t systcm is in oper,l, tioll
[II this dis('lISsioll, tlwrdo\'l', I sh,1I1 recxalllille some
of tll(' accl'pted methods of odor cOlltrol, with special
('ll1ph:lsis 011 what can gn I\wng ,'ilhn ill Ihe !T1I'Ihod,\
111<'llIsI,I""s or ill 0111 ,ISSlllllptioll\ a"ollt 111>11' IIlIlCh
1'01111'01 is IWL'I'SS.IIT.
Process Modification
('111'11,1<.11 1'10"('.\.\('\ :11(' so dil'('!'.'" Ihat it is diJlicll1i
I" .\II!~,L~t'sl sp''l'ifie rL'IIIl'die:.. NOI1"th('kss, process
1l11"hfi".dil'lI IIInits lir,1 ,'omidnalioll. 011 o('(',\siol1,
\hglil challg('s 111 111<' JHO('(',\\ arc III()JT dkctivc or
eh(',llWI thal1 ahatl'lIH'lIt prol'('duI"I's at the :;tack.
Altcrllallll']y, they may COllstitllle a lirst stagl' in 0<101'
ahait'll ICII I thai will reuuce the 10ad imposed on sub-
s(,lplel1t st.lges, Exampll's arc thc suhstitulioll of low-
odor ,\olvcnts or reactallts for high1y odorous ones, or
thc ,ldjllStllH'lIt of prol"~Ss tcmpcr;ltllrcs, n"i'}f~TI('C
tina's, or othn conditions so as to minill\ize odor
I'rodlldion,
The relatiollship hetween pn'l'I'SS Icmpl'r.lture and
"dc>!", IUII\ ev(~r, is "'" a simple 01lC, TII hi~~h-tr-lTIpcra-
Iw',' i:1I.gl'S (fnllil D:;O-I,~.')O F ) ;1 high('/" !1'II,!,nature
111<.'.1 liS IIIOr!' (,olllpldl' oxidation, which is IIsnally
1.(,lpflll,:1I I"\IIT ICIII;W',IIIII1'S, ,III ill''1'I':iS'' III I' 'liP":"
1,"" Ilia)" IIwall 1I1"r!' l'olatili'l.;Ili"II, l'lad,ill)!" or slilok-
CHEMICAL ENGINEERING/NOVEMBER 3, 1969
d
a -Average plume
b -Instantaneous plume
c -Puff
d -Single particle
ODOR CONCENTRATIONS along
line BC: a. Average plume, b. In-
stantaneous plume, c. Puff, d.
Single particle--Fig. 1
iug, which can be detrimental. These factors will be
disclIssed in more detai1later, under "air oxidation,"
Dispersal Methods
Wc aSSWlle that malodors become less objectionable
as Ilwy gd IIIOHJ dilute, and that they are abated com-
rld!'ly WI1011 their concentrations reach the threshold
1"\'1'1 of [H'r!'('plion, Siu('(J the dispersal of gas from a
.s1:\I'k can he, mOllitored hy tracers or calculated
thl'oJ"('tically. it .should b(~ possihle lu predict how
1IIIII'h odor call 1)(' l'ntlUed from a given stack without
l';\1,sillg a IIII;saIlCI'. If the actllal rale is higher than
Ihis c;dclllall'd value, the dispersal can be illereased
(hy r:llslI'g I III' ,tack), or the concentration of odorants
can 1)(' d('(TeaS('d (by some abatement device), or
hoth can he dOlle, with the object of diluting th(;
odorallt al grollurl level to below the sensory threshold.
This approaeh has been generally used in the chemical
i\1du,\tn' as a hasis lor design of odor abatement sys-
telliS,' In addition, dilution-to-threshold has become
lhe IllOsL prevalent method of measuring odors in air
pollutioll applkations (see Fig. 2).
"111f'f(' h:1\'e heen very few reported experimental
appraisals of this concept. 011e inYesligatiol1~ com-
p:1J'cd odor travel from four different plants. wilh
.s1;lf'k ,~a.'; dililliolls calculate(} according to Sulloll\
(''Ilial iOll, L:1r~e <1iscrcpnncil',.s were found. Tho most
-------
ODOR CONTROL. . .
---------.---- -
---
Measuring Odors by the Dilution-to-Threshold Technique
Principle:
Sample of odorous
air or process
exhaust
Same sample diluted
to odor th reshold
.8
c6
Dilute with
odor-free air
to th reshold
m = mass of odorant
V = volume of sample
C concentration of odorant
m = (no change)
Vt = volume at threshold
C t = threshold concentration
C= m/V Ct = m/Vt
~ ~[Odor dilution ratio.
C V Threshold odor number.
~ = -L = Odor pervasiveness.
C t V Odor units per cu. ft. (ASTM
. definition, V in cu. ft.).
Containers used:
Syringes
Plastic bags
Steel bombs (using partial pressure ratios,
Vt/V= P(Pt)
Flow syste~s (using flow rates, "I IV= QtIQ),
where Q IS flow rate)
Odor-free diluent air:
Usually ambient air purified through activated carbon.
Assumptions:
. Mass of odorant is constant (ignores effect of
adsorption on container walls at very low
concentrations).
. Odorant is gaseous (ignores possible effect of
aerosols or condensation nuclei).
. Odor threshold concentration is an intrinsic'
property of the odorant (ignores variability of
response criterion of judges).
The result theoretically provldel a balll for calculating:
. The degree of dilution needed to deodorize a
given odorous emission.
. The proportion of odorant that must be
removed from a sample of air to deodorize it.
. The volume of air that can be odorized by a
given volume of the odorous sample.
The result does not provide I basil for estlmatlnl: .
. The odor intensity of.the sample at
concentrations above threshold.
. The quality of the odor.
. The objectionability or acceptability
of the odor.
ODOR MEASUREMENTS are generally made by human noses that sniff carefully diluted samples-Fig. 2
,'xln'llll' sample was odor 1"1'0111 a kraft-paper mill, for
which 1111' aVl'rag(' dilul iOIl Iw('(h'd 10 reach Lhre.~hold
was :~:l: I, amI tht' IliaxilllUli1 ()4: I. The 1Ilinimll111 cal-
culalt'd dilutio\l of sta('k <'IlIul'\lL was mJo: 1, predidi\lg
Illat the odors would 1101 I.e dl'l('l'Icd ill Ihe field. Fi(~ld
~lIrveys 0\,('1' a siX-lIumt)1 pcriod show(~ll Lhal tlw
kraft odor could he del(,('[l'd al distances lip to eighL
I1liles, where the calculated dill1lio\l of the stack
effillent was R40,000: 1. There were occasional reliable
rcports of the ouor at a distance of forty miles!
My own experience agrees with these findings thai
the distance from a source at which odor may he
detected is not preuicteu even approximately from
dilution ratios and uispersioll calculations. Thcre arc
many examples of odor sources whose effects call bc
det('cted at distances of tpns of miles, hut for which
no thrcshohl or dispersion data am reported in the
literaturc. Not a single reporL appears in the IiteraLun~
in which outdoor odor I r~I\'('l h'JIII ., Sj)('rifi,'d SOl liT" is
successfully pleJiclcd, eitt.cr III conccnlralioll. illtcn
sity or distance.
Why the Inaccuracies?
WhaL arc the sourccs of those gross inaccuracies
IInd Il11corlailllit's? Several likely possibilities are:
Validily of Outdoor Dilution-Calculations-The
l1Iethod of ('still1alin~ the average concentration of a
pollutant ('milled frol11 a known source, as described
hy Sullon and more recently modified by Tumer,(!
requires ming certain atmospheric parameters that
describe the meteorological situation. Up to distances
of a few miles, and for durations up to two hours,
tracer tests have shown that the formulas yield average
concentrations that are within a factor of 2 or 3 of the
ohserved values most of the time. At greater distances,
the calculated average concentrations become much
1I10re uncertain, but should not usually be in error by
fl factor greater than 10 within the trajectory of the
plume. Odor complaints frequently arise from dis-
IIIIIC(',\ 'If 1I101T than thrce miles £1'0111 an alleged source,
and ~~rrors lip to al>out a factor of 10 arc tl.crcfore
plausible.
NOVEMBER 3, 1969/CHEMICAL ENGINEERING
-------
--- ---- ---
Cins!.=- ~
C avo -y ti;;;
(t::o Time)
Let hourly average concentration of odorant = x
Then, maximum concentration of
odorant in 1 sec.
..y 3,6oosec.
=x -
1 sec.
=60x
MAXIMUM ODOR is many times average odor-Fig. 3
\10rc serious, however, is the fact that odor com-
plaints are usually responses to peak levels-people do
n"t smell averages. The meteorological situation is
dlllstrate(l ill Fig. L. The shaded areas of the plume
(at left) represent a series of puffs of odorant matter
released from Point A; the dotted line indicates an
in<,tanlancous outline of the plume from a continuous
release at A; amI Ihc full line shows the outline of the
l"llg-lenn average plullle from a continuous release at
. \. The righl-haml pari of Fig. I shows cross-sections,
:dollg I he line HC, of the conccntration in the three
('.ISCS. Mdf'OIological dispersion formlilas give little
11('1p ill f'sillnatillg the ratio of peak to mean concen-
li'tli<1I', sillce the Il1ctcoro!ogk.d paranletcrs they
ill('orporat., arc I" a large extent empirical and are
\\'('11 eslahlished on I)' for prolonged release and
~Iv\'rag('ll 1>llIn1<'5. I\c('ellt analys\'s7. ~ ha\'<' suggested
I h,lI at ,I (,ollsiderable dislance from the source, the
('''lll'''lltr.lli')(l ill the pllff is l'roporti,,"al to t_i,
wli(':t' f IS thl' lill1(' Ilf r('!case (SI'C Fig. ,1).
VI'hat IH' do not know is how long or how fre-
qllcntly a pf'rson must be exposed to an unpleasant
"dm lwfm<' 11(' will ('ousidn it .I "l1i""I1("'. TI,u:; th(;re
:11'" largt' 1l1ll't'rt,linti,'<, illherent in all dilution cal-
culatio!1s for odor.
1'111: /'ossi/,/,' [{oll' of l'arliculalt' Mattcr-In the
\\ idely waltl'l"d lilt'ralllr!' 011 1111' 1l1(,~ls\lf('m<;nt. con~
11'01 alld IIII'm) of odol, il is rq)(',ilnllv a<'St'rt('d that a
"I III I[)()I 111<1 IIIIISI !)(' ,'ol:rlik to 1)(' odoroll\. 11 is some
III1\C\ .11<'0 illf"lTnl thai th(' IraJl'if(~r of ()(l\lrlllls
Illaicrinl r\'tJ11\ a solid or liq\lid sO\lrce to II lmman
\\'1\<,"1' ,11\\,:1\,,\ ,)('('111'\ hy vaporii'.alioll ,,( lilc sOllrcc
111.\lnial. alld hy <'111""1(11<'111 difFII<,1fI1i or I'IlIlvcclion of
th(' g:ISt'lIll\ odora\lt ulltil iI rea(,'I<~s Ihe \lOSt, of the
s\lhjt'd. !lowever, thf'w is evidence Lhal tltis piclure
j,s incomplete, and that particulate matter can playa
roll' in thc transfer and/or perception of odorous
IIlaftm hy humam. V:.Irious ('xperimclIl.<, sllOwing thaI
odors may he redllced by filII :.IIi, H1 meLhods, for
t'xample, support this possihility.
l'~Hticlcs !\lay contribute to odor if Ihey are volatile
(like particles of camphor), if they release adsorhed
odorous vapors, or if they are indeed odorous in them-
sclve.~. Since no study has eVl'r rignrously defined the
'll'Pt'l' limit of parlid(. si7,t' for ndorous malter, the
latter possihilily cannot he excluded.
CHEMICAL ENGINEERING/NOVEMBER 3, 1969
The implications of particle-odor association may
be even more serious than the computational uncer-
tainties outlined in the previous section. Thus, if a
single particle (d in Fig. 1) carries odor, it consti-
tutes transport without dilution.
Variability of the Odor Threshold-The odor thresh.
old is usually defined as the concentration at which
an odor can be detected (detection threshold) or
a particular odor actually recognized (recognition
threshold) by a given proportion (often 50 %) of
the population. The recognition threshold is consid-
ered to be the more appropriate measure for air
pollution work. The appearance of tables of odor
thresholds implies that these values are properties
of substances, like densities or melting points, This
means that each person has a barrier against odor
perception than can be overcome by 50 many mole-
cules of phenol, or so many molecules of ethyl mer-
captan, and so on, and that this quantity (or concen-
tration) of each substance is therefore its odor thresh-
old. Variations in odor threshold can be attributed to
variations in human sensitivities, and can be smoothed
out by selection of representative samples of the
population.
These concepts are rejected by modern "detec-
tion theory,9.10 which assumes instead that when
an individual responds to the question, "Do you
detect odor X in this sample?" he is making a de-
cisioll between signal and noise, both of which are
present in his environment. This decision depends
not only on the sensitivity of the judge and the prop-
erties of the odorant, but alsd' on factors like his
expectations :md his willingness to risk an error when
he answers "yes," or one when he says "no." Re-
cctly Engenl! has shown that simple reward and
punishment payoffs can manipulate the decision
criterion and, as a result, make the subject appear
"more scnsilivl'" or "less sellsilive" to a given odor-
which is the same as making the odor threshold
"lower" or "higher."
Applications of these procedures to studies of
odm s in air pollution contexts have not yet been
1 <'1)(lrl('d. However, the concepts illuminate such
",nil. known phenomena as complaints of odor when
tl,e presumed source is inoperative, or when the
wind is hlowing thl') wrong way, or the fact that
phenol is sometimes detected more readily from a
,SOIlI'("~ miles away than from its 1 ';I" concentration
ill tht) phenolated ('alamine lotion one applies to
rno.sC\uito bites.
Possible Rule of Secondary Sources-Attribution of
a commnnity nuisancc odor to a single source is
nftell all oversimplification. The error may become
significant when control procedures are applied only
to the major source.
It will be best to illustrate this point with a hypo-
thetical example. A manufacturer produces a certain
chemical by the catalytic oxidation of raw material
with air. After the oxidation stage, the process air
stream is discharged to the atmosphere. A com-
munity malodor is attributed to unconverted starting
-------
ODOR CONTROL. . .
.----.---
-- --- - -
---.---------- ------
Before
oxidation
CH3SH ~ S02
After
oxidation
+ CO2 + H20
\ I
Approximate odor
threshold
Odor level,
assuming source
concentration is
0.5 ppm.
1 ppb.
Stench
(500 x
odor
threshold)
1 ppm.
Odorless
(below odor
threshold)
odorless
OXIDATION, if complete, removes odors---'Fig. 4
material in thc cxhaust air, which is ~ubseqt1cntly
disp('rsed.
Calculations based on the otlor thn,~IJOIll cUllu:n
lration of the raw material and on the cxpected at-
mospheric dilution predict that a 90% reduction
of the odor's concentration in thp. exhaust stream,
plus a doubling of the stack height, will eliminate the
problcm. Accordingly, the stack height is doubled
and a two-stage activated-carbon Hnit is installed
which, by material balance data, is shown to recover
90';:, of the raw material formerly discharged. How-
ever, community complaints about malodors persist.
The question is this: 'Vas the predklion concem-
ing the exhaust air strcam incorrect b,~cause of un-
certainties descrihcd previously, or are the malodor
complaints now being generated hy odors from
other sources?
It is recognized that the exhaust air stream was
originally the major source, hili, after installation of
the abalel1l<'ul system, cumulative seconllary sources
may bccomc rclatively significant. These would in-
clude vapor dispJaceIH('1IIs from transfer operations,
vapnr evaporation during cataly~1 bed cIcanouts,
vapor I()s~cs of olher materials that aw produced as
byproduct strcallls, various spillages, leaks, de.
------- -- ._-~-----
-----. ----
- .-- -------- - - ----- -----
RH
Saturated hydrocarbons
(almost odorless)
ROH
Alcohols (low odors)
ArH
Aromatics (moderate
odors).
CHzO
Formaldehyde
(typical aliphatic end-
group product)
RCOOH
Organic acids (sour
odors)
ArCHO
Aromatic aldehydes
(fruity odors)
Partial )'
oxidation
,?o
-C=C-C
/ I "-
a, fl-unsaturated
aldehydes and acids
~irritating pungency)-
-----"- -- - --- ----- -- - --.
. - ~. -- - -. - . --. - ..- - - - - ---
PARTIAL OXIDATION may make bad odors even worse, but complete oxidation removes them-Fig. 5
NOVEMBER 3, 1969/CHEMICAL ENGINEERING
The important point is that tho qU3stion ca,nnot
be answered in the context of a chemical rnanufac-
turing operation, The secondary sources canno't he
eliminated for the purpose of conducting odor tests
without stopping the entire production. A further
abatement of the primary source may yield success, but
if it does not, the same question is simply displaced into
another range of concentrations. Furthermore re-
peated redesign of fuIl-scale abatement procedures is
prohibitively expensive.
ODOR CONTROL METHODS
We wiIl now consider some of the generally recog-
nized odor control methods. Remember that all ex-
cept the sensory modiBcation methods (odor masking,
etc.) reJuce the conccutration of discharged od('r,JU~
watler 10 the atmosphere. The uncerlainties jI~ d.,tr r
mining just how much reduction is neccss:uy are
the same as those discussed in the preceding section
on dispersa1.
Air Oxidation
Complete oxidation of odorous vapors eliminates
their odors. This statement includes sulfur and nitra-
gen compounds in air pollution contexts, because
their oxidation products, even though odorous, have
comparatively very high threshold values (Fig. 4).
When oxidation is incomplete, however, the odor
quality may actualIy get \vorse before it gets better
(see Fig. 5). The various components in a complex
mixture may undergo oxidation at different temper-
al ures; it is therefore necessary to ensure adequate
conversion of the most "refractory" (difficult to oxi-
dize) component to ensure adequate odor abate-
ment.
There are three general methods of air oxidaoon:
flame, thermal and catalytic. The typical Hame unit
is essentially a Harc that is operated within a com-
----"""I
More )'
oxidation
~eneralized J
burnt odors;
suboxides such
as C302. etc.
Most components
unknown. ,
Complete
oxidation )I
C02 ,
and
H20
(no odor)
". ---- ----.--- .- --
--I
-------
--m-
~- ~-, ~
, r------- n "~':' u- .'~. '-7'. .
~ . -, - .'-, -c=- -',
JS-- " '-../ ---
,--X'----, -,,::_~-;:~:- _0" -...:=:=:--=/..-
1)U.~liOl. chamber under carefully controlled condi.
I ions (Fig, 6); auxiliary fuel is usually added to
IIlaintain flammability. Thermal incineration occurs
at hot snrfaces in the absence of injected fuel (Fig.
i), Catalytic combustion usually utilizes a precious
metal catalyst to attain conversion at minimum tem-
peratnres. These methods have been described in
previous reviews.12 The over~ll sequence of applica-
bility is:
Flame -'> Thermal ~ Catalytic
Decrc:l.8ill~ COllcentratiollH ()f comhustihles
---,)
'!',Ihle 1. takcn frulIl IIardison,12 gives ranges of oper-
ating tell1peratures amI costs for the three methods.
Nuk Ihat these numbers are grossly approximate,
with uvcrhpping cost ranges, and cannot be used as
pr('dictors ill individual cases.
Li~le(1 IWItHY are some of the main prohlems in air
u,idation to which the engineer should be alert:
Catalyst Detrrivratian-Catalyst surfaces may ac-
clllllUlate relllOvable dirt or ash. such as paint pigment
resioues. that obstruct Ille access of fumes. Periodic
washjng may relieve the problem. More serious arc
[me c.ltalyst poisons like lead, zinc, silicon and phos-
phorus that necessitate reactivation of the catalyst.
Selection of Tempcrature and Residence Time-
1'u('1 costs in air oxidation are so critical that it is
ill1port:mt to determine accurately the conditions
lI('edcd for optimum deodorization. Temperature-
rise indicalions or chemical analyses do not satisfac-
toril~' predict odor-ahatemcnt pcrformallce, especially
\\ 11t'1i iulcnncoial<' oxidatio;1 products may be pro-
duccd, It is [,cst therefore to lest a pilot ul1iL by direct
- -- ------_._------
fuel
Stack
t
I
Cooling
air
Natural gas
FLAME OXIDATION system is an enclosed flare--Fig. 6
Stack
)
tOtQt'
Odor sources
CHEMICAL ENGINEERING/NOVEMBER 3, 1969
1 HERMAL OXIDATION systPJTl. OXidation occurs on hot surfl:lces; no fuel is added-Fig. 7
"----.----
-------
ODOR CONTROL. . .
Methods for incinerating waste gases-Table I
Operating Equipment Annual Fuel
Temperature, Cost, Cost,
of. $/Scfm. $/1,000 Scfm.
-------------- - -- ---------- ---" ---. ---
Flame 2,500+ 5-50 0-20
Thermal 1,000-1,500 1.7S-10 G- 7.50
Catalytic 600-900 1.75- 5 0-- 4.50
sampling of the hot ('mucnt into an cvacuated stainless-
steel tank. The tank cptlknls are thcn diJ1Ited hy
pressurization amI prcscnk(l 10 jll(!ges f{lr evalua-
tion (Fig. 8). In this way, a grid pf oxidation tem-
lJ('rat1lJ'es and residence times ('an be rapidly
C'Xplored. Eaeh tank contains enough s:1mple for evalu-
lion hy a panel of judges.
COlli pa l'iso 11 With Solt'l'lIt Hrc/JIJ(>ry-Favorabll1
heat-rt'cov('rv ('conomics arl1 110 assurance that air
oxidation is the hest chokc for odor abatemcnt. In
fact. the morc attractive the oxidation, the more the
cugineer should consider thc possible alternative of
solvellt recovery, because a high concentration of a
\'aluable component (for example, toluene) may
h(o worth more as a solvent than as a fuel.
Oxidation by Agents Other Than Air
Other oxidizing agents used for deodorization in-
clude ozone, chlorine, chlorine dioxide, hypochlorites
and permanganates. It is important to recognize that
these agents generally do not convert organic sub-
stan('es to their most highl}' m:idized prodnd~ (C02
and H~O), and therefore the question of odors of
illtcrmediates may be critical. For example, ozone
COIlverts a mixture of styrene and vinyl toluene mon-
omers to :1 mixture of aromatic aldehydes with al-
1I10nd an(1 cherry-like odors. 111is may not be bad,
hut it iSll't odorless. CldorillP treatment sometimcs
yil'1ds chlorination products th:1l arc more offcnsiw
than the original odorant. Obviously, each situat,on
requires spparate cvalaution.
Adsorption
Activated carbon is the only practical adsorhent that
can he used for odor control because its performance
is not weakened by the presence of moisture. How-
ever, there arc several aspects of the behavior of acti-
vated carbon systems to which the engineer should
bc alert:
Catalytic Action-In an activated-carbon solvent-
recovery system, tJ1e adsorbate is stripped off with
steam. It'aving [] fresh. hot carhon her!. Spch hot
carbon is an elfeclivc catalyst fUi various oxjdation
and decomposition reactions; hence, if it is not al-
lowed to cool before heing returned to the a,r1:;orp-
lion cycle, a malfunction of tlw system Jllay resnlt.
In one such case, methyl ethyl ketone (MEK) on
hot carbou was converted to a complex mixturc 'of
contaminants, including acetic acid and some acrv:eill
Jerivntives, making the odor effluent more objectidn-
able even ill the face of 90% material recovery of
the MF.K. Proper cycling of the system solved the
prohlclI1.
Rapid Saturation From Spills, Vapor Surges, Etc. -
The service life, t, of an activated-carbon system j~
given by:
srv
I - - ---
- EQC
where S "0 pruportionate maximum saturation of the
carhon (fractional); W = weight of carbon; Q ---=
1';11(' of ;Iil fL)\'" thruugh carbon (".nlmn('/ti"~.,
c: :::: concentration of odorants Ly weight (wd;';;Il;'
volume, units consistent with those used for ,V and
()); E = adsorption efficiency (fractional, usua1lv
dose to 1).
Usually the factor least subject to prediclion or
('outrol is the coutaminant concentration, C. FurtJH:r-
I1I000e, when a carbon system is designed for abate.
nlcnt of offensive odors, concentrations on a JHa,,~
hasis may he quite small, and the relative effect of
an accidcntal spill may therefore be great. In fad :1
carbon system is sometimes designed only for ranuom
discharges, such as loss of radioiodine and radon from
a nuclear reactor, or spillage of mercaptan from a
gas odorizing site.
On some occasions, the source of the adsorbate
is mysterious, as was the case in a large hotel in-
stal1atiol1, in which the carbon bed became saturated
in one month instead of its predicted service
life of one year. The source was finally traced to the
:-..ylenc solvent used (during the nighttime, by an
outside contractor) to clean the bowling alley lanes
in the lJasementl
Some of these problems can be anticipated in
designing the system. In the scheme shown in Fig.
g, with a dampers 1,4 open, and 2,3 closed, the
,llwnstream bed B serves as a standby to prevent
systcm malfunction if a random spill saturates the
upslrealll bed A. When A becomes saturated anu is
replaced with a fresh bed, it is economical to reverse
the flow (dampers 2,3 open and 1,4 dosed) to
utilize fully the capacity of bed B,
Special Reactivation Methods-The approximate
range of contaminant concentrations from 5 ppm.
to 500 ppm. represents a special problem in odor
control because these values are high for activated-
carbon systems when the contaminant is not worth
recovering, and low for oxidative systems. SQch
concentrations saturate an activated-carbon system
rapidly and are not high enough to make any appre-
ciable contribution to temperature rise in an oxi-
dation ~.\'stem: both effects are economically {lis~d.
vantageous.
It seems sensible in this concentration range to
NOVEMBER 3, 1969/CHEMICAL ENGINEERI~G
-------
Stainless
steel ta n k
(a)
~~~r
[
o
(b)
~
~dt~:,~
~I...
L{
(c)
-~- --
------
DUAL-BED activated carbon"
system uses downstream bed
as sti1ndby if random spill
rapidly satlli i1tes the upstream
bed--Fiq. 9
---- --- "-----..
----- ----- -
-- -- -_.- ----
Out to
atmosphere
t
._Jl
- ~~ - -~---
5~':~-::'~~
~,:,i,'",,-,:'~',) '/ . \
~!.i:.:~~'d;.L:. ~
T .rt- ._- =tl
l,,,j \_, Darnper
f
L ------ -- ---. -.-. '---. -_.
- -- --- ----- -- -- ~----
. '-Catalyst
Carbon bed
- Resistance
heater
StPiHl1 id
I
--~
CHEMICAL ENGINEERING/NOVEMBER 3, 1969
~ SMELL. TESTING effluent from
hot exhaust. a. Sample to 20
torr. b. Pressurize to 2 atm.
(approximate 75:1 dilution).
c. Make sensory jUdgments on
dilute sample-Fig. 8
Out to
atmosphere
t
3.
t
---. ----
.--
. CATALYTIC OXIDATION and
adwrption are combined In
this dual bed, parallel arrange.
ment-Flg. 10
4
2
-------
ODOR CONTROL.
combine the two approaches; that is, to concentrate
the contaminants by adsorption and then dispose of
them by oxidation. Then' arc two approaches to this
combination. The first is illuslrated in Fig. 10, which
shows two parallel arrangements of a carbon hed
and a catalytic. oxidation unit. Bed A is first used
as an adsorbent. \"hen it is saturated, the contam-
inated air stream is diverted to Bed B, but a small
flow of hot moist air is passed through A for reac/:i-
vation. The desorbed efHuent is then catalytically oxi.
dized to prevent discharge of odors. The energy
requirement for incineration is thus drastically re-
duced by the concentrating action of the adsorbent.
"Then Bed B becomes saturated, the damper positions
are changed and the cycle is reversed.
A second approach to achieving the same objec-
tive combines the adsorbent and catalytic action in
the same bed by impregnating the carbon with an
oxidation catalyst. The catalyst becomes active only
when the air stream is heated, and the adsorbate
burns itself off. Some years ago, I reported1:! that
this effcct can be accomplished without burning the
carnon. Systcms of this type are not yet in use
hut they arc beiuJ.: dev('lol)('d.
Washing and Scrubbing
The terms "air scrublH'r" amI "air washer" de-
SLTih{' various typ('s of {'(p1ipllll'nt that remove either
partie!es or vapors from thl' air by liquid washing.
Sueh equipment may thereforc he useful for the
('ollt1'01 of odors. The air conditioning industry uses air
washers to control tcmperature and humidity and,
as added benefit, to help control odors. The textile
and the chemical industries, among others, apply
scruhbers either to rccuver valuable vapors from an
air stream or to remove ohjectiunable odors.
The dfeetiveness of scruhbers for odor abatement
is difficult to pn'dict from chemical and physical
lI1ensnremcnts. As an ('sample, an offensive odorous
eIHuent from the dehydration of animal matter is
found 10 con lain a significant cuncentration of am-
lIlonia. Lahuratory studies show that when the am-
lI10nia is rell1ovt'd by water scruhhing, the total
IIitrogell cOlltent of lhc cIHllcnt is reduced by 95%.
NOlletheless, water scrubhillg may yield no meas-
urable h('lu,fit in the reductioll of community mal-
odors. TII(' "dor of amillunifl Itself is rcudJly reduced
to the threshold level h}' dilution, und therefore does
not :!('collnt for (',m,p!aillts from distant locations.
~Iany or~alli(' nitmg('11 compollnds of higher molec-
Illnr wl'i~ht arc esln"llel}' olfensive cven in parts-
['er-hillioll t'ont'('llll'ations. alld arc not removed by
water scrllbhing. Thus, iu this case, scrubbing has
creull'd a walt'r pollution prohlem without reducing
odor complaints.
Counteraction and Masking
The sensory quality of an odor may be modified by
the addition of other odorous matter under condi-
tions that do not involve chemical char,ges. When
such modification is used for odor control, the
process is called odor counteraction (implying an
overa1l reduction of intensity), or odor masking
(implying that the quality of the original malador
is obscured). The method is used in competition with
chemical, adsorptive, or scrubbing systems, and
for unconfined odor sources such as lagoons and
ditches, to which other systems cannot readily be
applied. The relative effectiveness of odor modi-
fication as compared with the physical/chemical sys-
tems is very difficult to evaluate. Scales of odor ac-
ceptability, long used in the food and beverage
industry, have not been developed for community
malodors. Furthermore, the installation of an odor
modification system is often accompanied by other
changes ( such as improved housecleaning, disinfec-
tion, increased confinement uf sources-a1l to the good)
so that strictly comparable before-and-after compar-
isons cannot be made. Finally, the udor preferences
of the populace are not stable, and their reactions
to any community odors may change significantly
from time to time.
The above deHneation of odor control problems
implies that this flfea of air pollution technology does
IIot always lend itself to reHahle predictions. Until
the udoran l propcrties of suhstances are better under-
stoml on a theoretical basis, tbis will probably con-
tinue to he the case. -'
References
1. Von Bergt'rt, J., ('II('n!. Enll., AUg". ]f)!)7, p. 239.
2. Turk, A., ()j::;perslnn a~ a Tool for Odor Control,
~l~~{~ tj')IO Ifl~ tl~n rn(s~~ rr~~l ui ~~~.~ -~\}~~~}~~t~~~ t~el~e~~oV~
12, lUG!:!.
:I. Wohlers, H. C., Intern. J. Air lVfltn' Pollution. "I, pp.
71-78 (l96:!).
G. Turner, D. D., "Workuook of Atmospherk Dispersion
E.tlmlite.," LJ.R. Puullc Health I:;('rvlc. Puh. 9~9-AP-26.
1967.
7. Pa.qulll, 1"., Metcorol. Mag., 90, p. 33 (1961).
8. Hillo, M., Atmoo. Environ., 2, PI'. 149-165 (1968).
9. Green. D. M., Swete, H. A.. "Slg',".l Detection Theory and
Peychophy.h:B," Wiley. New York. 1966.
1 O. ri\~~~n fjhB~~ve~~,I.lfr\~ille~,e~~~o~ o;'k.d 19IJ:cognl tlon by
1 L. J'~Ilg-en, T., Mau'~ Ability to Perceive Udor~, 10 "Commu-
, IItcaliun by Chl~mleRI BIg'l1alH," ed. by .Johnstun, J. W.,
J~. 1.}~:di~o~,Pr!.~tJjI;~~~~r~;( g~~:etf~u;~WasreO~~kp~~~lerPt~BJt
~:~~~1Igi.~v~~~t~~~~~IJ~}ls.M0:;\~,P~~~7j(7~'Pd by gast OhIo Gas
J:i. 'I'url<. II.. Ind. f
-------
LATEST METHODS )'011 CA:-.I
I :SE FOR
Industrial Od.or Control
Prop('l' US(' of (HloJ' ('u1I11"01 met ho"~ (cuU1lllli'tion, (~oun1CraCli()ll,
(.tl'.) i1lll'rn\'l~H puhlie ..dationH, employee morale, properly values.
.....IN V..N 1''':'U.I~l\. :'Irk.'"" 11U~., N.,w ,-..I'''' .'ltyoJ<
O. 1101(::; and 1'111111"" ;11'1' Ih., Ji;lIlIl'al "v.
pl'odlll'l or 111:111;,' ,'IIi'l1Iical IIllllillra('-
1\lI'ing JlI'OC"'H';l'~.
Up ullLiI ;\ f..w I.t aI", ,11'.\1, \1<1,,1" IVI'I'l' 1",.11'
siderl'd :-iomt'!.hi\ll-( ill,~\'it.ahl.v 1'1''':,1'111 al'''lIlI0llit. 10 PI'OYI'
pal'tk!ll:tl'ly whl'lI till' :qII'IO.llldill~~ "0111-
mlillil,\', :;,tI'r1}"I'g','d ill a lIi:;a)('I""':""" Od"I',
hH~; h"I'1I :"'\111.""<\ I"Y 1111 in r"I'IIIo',j 1'11111"1':;
alld l1Iisil'arling' illf"l'lIla! iOIl
Ttl" 1\('\\ nll,thi'd,.~ ": Lld'l" f 1,11' ~ iJ! ltaVt'
,,,,,,,,, "1.
"
1,\1 "li
m:l'olllplislll'tI nlur'h in a "hol'l. l.ilTlI~ for I.he
ilJljll'oyemt'lit of (:OITlJllllllity rplations and
"Ialii. l'rnployl'C mOl'ale', 'I'1I!',;e factors, to-
I!.('I h. 'I' wi t.h l'OIl('t~1'1I OYl' I' 1l'''I'C.'s~wcl prop-
(,I'ty \'ahl(,s dlie 1,0 odol', and lilt' general
dl.~l'OIll fOI'L of OdOI'OIlH ':1l'l'a,;, have 1111 COm-
hirll'd in IIper\iug' I he rloorH to an intcJlil\'ent
111111 lo~:iclIl appl'o:u'h towardH t.his p.rohlern.
Indusl.ri:1.1 odors HI"! IIOW rl'co.'~nizcd a:; a
Y"J:y .it'liUit.l' pal'l. uf 1.Iw oVltl'.all air pullu-
tion "i,'l.lIrc, Chetni,'al 1'lIldlll"'I'H l'ollct'rned
with 1111' l),o:IiIPI, :-IlIpel'yi~don or administrn-
11"" or clll'lIlkal "lalll.H sholiid !JIICOIIII~
familial' wit.h till' laLl'sl. meUiod,; alld tech
I,iqll('" aVidIIlIJ'" r"r ,'olltrolliu~ indu8trial
(IIIOI'S,
Some ot/Ol''; ;1I'l' I'I,!J\'C}'crl "" Jillirid alld
~,,"id part.ide,; FiILI"'s, electrical j'l ,ipJ-
I:tlol','., ,~nni(' fllIl'I'llb,tor:;, l'.\'('!1I11l' Hl rllhher,;
"!" "t!li:-i';iOI1 [')'("11 ('II('llli",il 1';'l,l.:lnf'l'r'inL'
------~._-
-------
MtctIW Method, for Controlling Industrial ~on
. CombU8tlon
. Abeorptlon
. Adaorptfon
. Odor Madlna
. Odor Counteraction
MOlt Common Source. o' Odor
f.rtIII- manufactur8n
PhtI wa.'... '
Sp.II' oddL
COtlll8l'l and food produce,.
EffIueIIh and dumpL
To"".rl..
EffIuenh and dump..
P'normoc.utlcal plant., br.werle.
Fermentation watte$.
Petroleum refining
Effluenh. wast. go....
Municipalities
Dumps. lagoons, 18Hllng ponds.
Ch.mlcal manufacturers
Resin.. adh..lve., rubber. points, varnish
coating., fats, oils. ek,
1ell:ll/e and paper
Dumps. s8"lIn9 ponds, '''goon"
,If"!' avail;d,].. I",. f"!'nH>\'IIII~ 1 IjI';;, ,
p:lI,t,i('I,'s, (:;"" 1'/"'/11. /';Y/t/, (),ol.
j!);.;:) ~'l",,,1 11>1..,.,: ''''''III' III t h,'
):a~"oll:' pli;l.''' , alld \\'.' will 11'~'l'iC't
IIlIl' din("I.',si/11I 1,. thi~ t.,\ I'" III'
/l1'(lhl"11I
Fi r...1 SkI': (.clur Sllrvc~y
,\ ','!I \"\' ..I' ,h'd pllhli(' ,,'li('i;\1.~
"',"1',,:1: i'd.' 1'..,. ; iiI' '',,,!In.\ oi' :111'
pnllii! i(lll Ii' (;7 major illd"slll;d
,'dil's I\:h (,oll>l'ld('d ill I!);;G,' Tah,
Id:iljoll "I' ;111,\\'1'1',1 10 IIII' roll,,\\'iIW
\irH.';'ili,' {j111','d tl)!1.~( \Va."" rn;,dt.:
(,) ;)11 VI'!I "(TCIVP rnaIl\' ('(lrll~
"I:.illl" :d,..,,1 "dill's "illl('r ,~"pal';ill'
rro~1I ()I' ;H'. OI!lp.lnyil1v 01.11(',. fclrrlls
"f :1 i r 1',,11,11 i"II"
t ~1;l:1\' (''''l1plaill!..~ \",,1'" 1'(',
I'0)'!I'oI It.~ /'(,"" "I' 1.111' n~:!pol1(Ic'l1t:;,
Trlmethvlamlne..
Mercaptans, r.duced .ulfur compaund...
Product. of nitrogen' compound deCGfll",'
po.ltlon.
R.duc.d ,ulfur compounds, caproic add,;' ,
Amln... reduced lulfur compoundL
MercaptClns, ~S, ammonia.
Product of nitrogen compound d....
position,
Phenolics. sulfur compounds, formald..
hyde, solvont..
Ureo. storch decompo,'tlon j)roducts,
M"I'" Ihan half of lhl'se .iudgl'd t.haL
t I", 11111111..,1' of "(Ol1Ipjailll;; WI~W ill-
1'''fl:ISln,~.
(,I Po ,\'011 1"'I,llh,.,." i" ill('I"';l.~illg'
11111>111' iIlL,'n'.';!. in odoh p)'ohll-m;; in
YOIII' "OllllTlllllify'! '
'\. y,,;;
No
No all,',WI'I'
liWj"
20'1"
I~?;)
I). W'H"d ,\'Ol! pIPa;;" illdi('ale lIw
,~(\III'l''';; of odol':: ill YilO' 1'0011111111-
it,\' at thi;; tin1\' 01' in /w pa,.;t'! (In
ol'dpl' !If 1'1't''III'III'.\' !If ~1f'lIl.ion, h"I'('
an' tlw ;;IIIII"'(\~ 01' III (,,'S, Thl' fig-
111'(',,: n:fl'r to I,llI' ';;, I" oi' 'Iw,~l iOIl-
IIHjrl~:< ill whi('h 111('; ~;OIJl'I'1' wa,.;
I'itl'd, )
..\.
( :1"'lIli(,;lI~
\'..11 i,'I('s
!'ai'd, a'lI>I van i.1t.
Fnod ,Irctl'\",'.'il i..
.. \ .
Jj~) (;;,
:17 Ii:,
()~(,;;,
r-:~ ();,
Domestic
(homes, etc.) 45%
Rendering plants 43%
Plastics 38%
Oil refineries 81 %
Coke works 31 %
Rubber 27%
Steel 25%
Insulation 21 %
}o'illh 21 %
Gall works 19%
Pharmaceutical 19%
Soap and detergenh 17%
BrewerielJ 15%
These summaries are significant.
Our industrial growth has resulted
in the production of great quan-
tities of products which were un-
known at the beginning of the 19th
century, Our automobiles alone
pour 7 milIion tons of exhaust
gases into the atmosphere daily,
The chemical industry has experi-
enced a seven-fold increase in sales
over the past 30 years.- and this
growth is continuing at a phe-
nomenal rate.
In spite of many other sources of
air pollution, the fact remains that
ma.ny individuals continue to blame
chemicals in general for increased
air pollution problems. It is inevi-
table that control agencies will in-
crease the pressure for odorous air
pollution abatement as time goes
on.
Chemical enl{inecrs sland directly
in the path of this pressure buildup
and the chemical industry has many
!lerious odor problems for which it
lIee(h~ answct'S,
Uf'IIIOVC Odor lit Sourre?
H is po~~ible, of course, to con-
lrol odors by e1iminat.inl{ or reduc-
inl{ t.heir ~ollrce. This may involve
rI~arranJl,'ing' or ~ubclividing the
molc~ctlle~ of alt!c~hydcs, diamincs
~1H:h as Plllrcscint' and cadaverine,
dhylaminl's, indoles ine1l1ding IIkn-
toll', th iOlllideH, hyt! rOl('ell sulfide;
amrnonililn sill/ide, organic: acidH,
phcnolll, cresols, i!lOl~yanides or car-
hylami n('II, Ift,toncs, mercaptans,
m'~r(~apt.ide:;. methylamines, thio-
cyanatell and many other compounds
dis(~hargecl by chemical process in-
dustries.
Specnk treatments that can be
applied may fall in the cla!\sical
dwmical reactions: neutralization,
acid i IIcnl'.i on , alkalization, oxida-
tion, "CHlliction, hydrolysis, poly-
ml'rho:atiol1, etc. Impro\ll'mt'nts in
proce:;s ml~thodlJ, l'qllipment nnd
hOIlHckl'epinl{ can reduce the vol-
ume of cxhauHtll.
-------
If the gaseous wastes of an in-
dustrial process are known or can
be predicted with some assurance,
their possible destruction may be
aacertalned by a study of the liter-
ature.
Actually, in most cases, analysis
of chemical constitution of a com-
plex odor is a very difficult job.
Almost as troublesome as composi.
tion, Is the possibility of multiple
odor sources, Also, a change In
process Is seldom practical or eco-
nomical.
To avoid neighborhood complaints
and generally bad public relations
the chemical engineer ahould ex-
plore an ounce of prevention. This
ounce of prevention can take the
form of a careful study on plant
odor offense possibilities in the sur-
rounding neighborhood area.
How 10 Apprall" Odor
The atmosphere surrounding a
plant has great capacity for dis-
persing odorous effluents. Favorable
influences are stack height, gas
velocity and gas temperature, Ad-
verBe influences are aerodynamic,
terrain and meteorologic,
Under favorable weather condi-
tions, odors from a plant will rise
~radually as they flow' downwind.
Contaminants will disperse until
only a negligible concentration pre-
vails In the atmosphere, Under
thf'se conditions and conditions of
nctual vertical dispersion, odors 00
not ordinarily become an annoyance
in the complainin~ area.
There are many nntuml influ-
"Ilces, however, which arlfle to di8-
turh thi!! orderl,Y disper!!ion, Wind
f1owin~ past a plnnt j{enerateH tur-
lJulence In tllf' wnke of stacks Ilnd
buildings, Turbulent masses of
odor nbove and behind the build-
ings are brought down to the
I{round in a spreading area. This
i~ termed down wash. Under these
ci rcumfltances, concentrations of
odors may be very high in an area
close to the plan 1.
If odor escapes the down wash siL-
uation at the plant, it may flow
downwind and come under the ad-
\'er~c influence of terruin, Hills 01'
valle,vlI and bays and pockets may
;let lip current::! which entrap tht'
ndorll, Thel'mal influence in the at-
m01\phl!I'o plays a lal'j{fJ part In the
()V(>r-all IIiI' movement. Under con-
ditions of IIiI' invcrl!lon, large quan-
Ii Li(':01 of OdOl'H an' bro\1l(ht to the
I{rollnd over n lnrl(\) al'ell /lnd l:Ionle-
Limes held fnr hourI!,
Behavior pattern, dispersion and
diffusion of plant odon Is impor-
tant to valid odor survey work.
Sherlock and Lesher describe in
detail conditions of waste gas flow
with light wind and strong wind
under neutral or stable atmosphere,
In addition, they describe the ac-
tion of the gas plume under condi-
tions of idealized diffusion, thermal
looping in an unstable atmosphere,
gustiness looping, and meandering
of gas plumes, This work Is helpful
in understandlna- the basic prob-
lems of odor dispersion,
Set Up an Odor,Jury
In appraisal of odor diapersion
an odor jury is Important. AI-
thouSh the nose Is a delicate instru-
ment, the, physiological and psycho-
logical reactions many times distort
t.he perceptive impression.
Moncrieff" has mentioned these
basic facts regarding human olfac-
tions:
1. All hormal people can smell,
2. P "pIe suffering from brain
lesions, injured olfactory nerves or
obstructed nasal pabsages may be
anosmic (Incapable ot perceiving
odors) ,
3. Cases of preferential anosmis
or ability to sense certain smells
und not others, do occur,
4. Characteristic of an odor, as
well as the intensity, may change
on dilution,
5, Sense of smell Is rapidly
fatigued.
The problem of measuring psy-
chological accepLablllty is a com-
plicated one. A fall' number of
persons, for long periods of time,
eontinuolIsly or continually are be-
Bet by odorl'1 without the presence
of the material ordinarily causing
such odors. Cases of iIIneBs or irri-
tation make people pArceive or
imagine odors that do not exist,
Although it has been stated that
one of the most dependable methods
for ascertaining odor appraisals in
air pollution work is a population
survey, this does not mean select-
ing a few residents who have made
complaints in the past. Some resi-
dents have complained of odors
three months after a plant has been
shut down.
Tn :lpite of this, all nOl'mal people
('un pCJ'(:eive OdOI'!!, and the most
important method of gas analysis
ever employed iH the sense of IImell.
Smt!lIinl-r hUH Home IImitatioOR,
mostl,y quantitative, but hus many
udvantnKo!l over other mean!! of
. . . oooa CON'R~
analyses, Sampling Is automatic.
Analysis 18 made and the resulta r&-
ported almost Instantly. And the
apparatus (the nose) is r.early al-
ways in a position to obtain the
sample of greatest immediate Inter-
est, No other preeent method of
analysis is capable of distinguish-
Ing between, and correctly report-
io8', so large. variety at chemical
substances by a single operation,
Some P"loaple. of Odor
A great deal of odor exploration
has been extended to the organIc
!lerles embracing aromatic hydro-
~arbons, alcohols, phenols, ethers,
organic acids, aldehydes, amlnes,
ketones, ketals, halogen compounds,
nitrogen compounds, sulphur com-
pounds, parafflns, esters, and others,
Such exploration involves satura-
tion and unsaturatlon, open chains,
closed chains, straight chains and
branched chains, Isomerism, odor
carriers, and odor extenders.
The outstanding facts established
indicate that no slngie pattern of
chemical structure serves to main-
tain even a trend of properties,
Complexity of odor research, and
for that reason the value of using
the experience of the odor chemist,
is indicated by a very few of the
hundreds of principles that have
been advanced by odor researchers.
The few p.-inciplea listed below
are only an Indication of the com-
plex problems Involved:'
. Compounds of olfferent. con-
Mtitutions may have 'similar odors
(camphor, silicononyl alcohol, du-
rene) .
. Compounds of very similar
constitution may have different
odors. If, however, the constitu-
tional differences are slllfht, odor
differences are generally corre-
spondingly slight.
. Polymerisation reduces or
destroys odor whether in elements
(red phosphorus) or In compounds
(glycols) .
. Un saturation enhances odor
but does not Initiate it (paraffins
are odorous).
. In the parafflns, straight and
branched-chain isomers have simi-
lar odors.
. In a homologous series the
odor will rise to a maximum aB we
ap,cend the sel'ies and will then fall
off owing to decreased volatility,
. Unsilturation often introduces
an Irritant note to the odor particu-
larly If close to a polar group (ali-
phatic aldehydes and, acids),
-------
ODOR CONTROL
O'Y Ca'al}'.,
Catalytic Fume Combustion Unit
Flg.1
Odorom
fumes
from
process
Cotaly.t~
(pt o.ide + nlekel wlrel
. A tertiary carvon atom will
frequ!'ntly induce a camph()raceou~
odor.
. Osmophoric influencE:' of the
phenyl group is stronR'. It over-
comes that of alkyl-ether gn>ups
and also of the amino gl'CUp.
Rali,," Sy"lcm. Are Helpful
To obtain valid surVl'YS it is
important to have at least ~even
1'1'1''''"'' ineluucd ill an odor jury.
ObsCrV('rH al"l~ lIot n('('c"sarily re-
qlllr&i to uemon~tratt' unusual
"Ifa"'or)' Ojnd.!'II\'ss or discrimina-
ti"l1 to qllalif~' for :, p:1n('1. On
111.. ,,1111'1' hand, Ih.. ,IUSprVCI'H "houltl
I I'y to I", ul>.lectivc ill Ihcir Opln-
I' 'I':', '1'1,('1111 irally trai nell labora tory
lit" '''11''1'1 a 1''' ,'x('pllenl for this
rj'a~()II.
1'11.. .I'II'~' 1'.~qllil'cS IL list of d\'-
S('I' I pt.i \,1' a lid I'nsil.\' JlIf!lIt.ll1ablc
t"I'II", f,,1' , 11111 form t.I"~"1 iptil)n
"f od",. i\!o:.!. lay pcop](> attc~mptillj{
II> d''',''I'iIJl' all odor g'l'l)pc for
"I>I/h, :,... ,f IIII'.\' w..n~ talklllg II
fl>l'..i':11 1:1'11:'1:11:", Odol' nH'JOort""
al'l' ,..,1,,,,1 :llId .ll'e sll.>c('pl ilile t.o
olll::id(' 1IIIIIIl'II('('S. If olle has bepn
I,dd 1111'1'1' IS all IHlllr of d"ad f1~h
fl "11\ ;1 ('l'l'taill plant VeC:ll1he nf
,':.illill'. (' V 1'1',\' lidoI' from that plant
I',,"id ;;1111'11 ilht: d.'ad t1"h tu 111('
IInl I'lilll'd 1I1"I'rver.
.\ dd',nit.. I'",dr for odo!' ol>:;crv:\.
1 i"n" ,",lId b.. "'fui"""" with ;\ 1'''-
1',,'1 '",n, "" \Illicit hl' (':111 IIIdil':ltl'
\1 il,d (>r-
vatinn run~ 1IhouJd be at approxi-
matcly lhc /lamc lime of the day.
(J~ually, the best time for obser-
vatioll j" in the evcniu~ whl'n air
illv('r.~lon occur,~ and m(),~t residents
an! at home. The evaluations may
r\1llt.inll/~ until midnight, and some
nh"crvation" should he made In the
('arl)' morning hours.
AlthouJ;'h it is not adviflable to
make i>urveys of the opinions of
residents, complaintfl initiated by
residents become an important part
of the survey, assuming the com-
plaint i.~ valle'!. All complaints should
1)(' !isted as to date. exact location,
lpn~th of rCilidl'n('e, de~cription of
odor" ail ('an he bp!'\t obtained, the
I\llmOeI' of timeR the particular odor
1\''1-< noticed over 1\ period of time,
ill\d th.. IIIIIP of day the OdOl" wall
noUr'pd. All of thi~ m/ltel'lal can he
Odor-
free
C02 .
+
H20
collected and shown graphically in
an excellent method by Gruber.'
A careful survey, coupled with a
report on residential complaints, is
the basis for determining the most
practical method of odor abatement.
Methods of Odor Control
Methods now commercially avail-
able for the control of odors from
exhaust slacks may be divided into
five general classifications: combus-
tion, absorption, adsorption, odor
masking, and odor counteraction.
It might be pointed out here that
the dilution and dispersion tech-
nique, where odor-containing gases
are put through a high Btack, does
decrease odor intensity. But this
alone is not a generally recom-
mended practice for odor control or
elimination. It depends too much on
wind and atmospheric conditioml,
which cannot be controlled or predi-
cated.
Combustion Methods
Fire is one of the oldest known
methods of odor destruction. It is
not a method of odor control, how-
ever, unless it is complete com-
bustion. Incomplete burning of
nitrogenous and sulfurous organic
material with the resultant pungent
oxides of nitrogen and sulfur is
not the ideal conclusion to an odor
destruct ion process. .
Partial combustion may be wor:-!e
than no combustion-evidenced by
incineratorll or the incomplete com-
bUiltion in diesel and internal com-
bustion engines which yield the irri-
-------
tating and sickening aldehydes,
with formaldehyde 88 the principal
ingredient ip thi~ group.
From a theoretical standpoint. if
complete oxidation of odors in the
air can be obtained, deodorization
is obtained because the final prod-
ucts are odorless (H,O, CO,) or
have a higher odor threshold than
the products consumed. For exam-
ple:
Butanol
! 02
- Mild odor
Butyraldehyde - Bad odor
! 02
Butyric acid
! 02
- Very bod odor
C02 t H20
- Odorless
Considerable progress has beelo
made in an attempt to reach com-
plete deodorization by use of cala-
lytic burners, particularly in elimi-
nating odors from fats, oils and
fatty acid processes. The only limi-
tation of a catalytic burner is that
the combustible substance intra-
(Iuced into the hurner mUi'l he in
t he vapor phase or musl be vapnr-
izahle at 11 reasonable temperatllre.
Noncombustible inorganir s()lvent~
are not affected by a catr.lyst and
should be absent from the air
stream.
As to complete oxidation, it must
yield innocuous products in order to
serve the purpose of od(,rous ai I'
pollution control. In the compounds
uf carbon, hydro~en IInd oxygen,
which cover a wide field, this is true.
In the case of hydrogen sulphide
or organic compounds contain-
illg sulphur, catalytic combustion
operating at tempel'atures below
mfi 10'. or above 1,250 F. will con-
v!'rt sulphur to sulphur dioxide
Il'8S offensi\'e and les;1 rilJnl{erOII~
thall many of the ori~~inlll sllb-
.slann's as lonl{ as the dispersal
I"vel is well below th(! maximllm
p!'rnli.ssihlp level in tilt' nell{hhol'-
hood.'
(;('11('1'111 J'ld(!s for organic corn-
''''" lids ('f)ntninilll{ lIill'Olft!1l nrp
dilli('ldt. The CmUI'IIt may contlliu
frp(! Jlilrol{en (II' its oxidell depend-
illg' on the cunditions of oprl'l\tion,
Reduction of nitrogen oxides will,
of course, release free nitrogen.
Cotalyftts Lower Temperolure
Use of catalysts to aid combus-
tion is illustrated by the design of
platinum alloy activated alumina
coating on porcelain rods or plati-
num alloy coating on nichrome wire.
Odorous air, pr.'lf\ed through a
catalytic device, may be oxidized at
temperatures 500-800 F. lower than
required by unratalywd incinera-
tion. A major contribution offered
by catalytic comhuHUon is the COII-
lIiderable lowering- of t.he firing
temperature, wilh reHultant saving'
of energy for heating air, and cap-
ital equipment ('oHllI for heating ca-
pacity.
Some comulls!ion processes may
operate withou t. an outside energy
source, except for that required to
reach tl e firing' temperature. 01'
with smaller fuel requirements,
where . '~h operat.ion would nor-
wally !.a VI' h(,1'11 ('('onomically UIl-
feusible in llllca~I'. '('J inr.inrra-
tion (Fig. 1).
Temperature for dfeclive com-
bustive deodorbmt.ion (](T<:nd" to a
l{J'eat degree on th(' ch('mical na-
ture of lhe vapor lo be oxidiwd and
on coneent.ration in th" inl..t HtI'C
-------
ODOR CONTROL,
effluents to a sati::lfactory nrinlt
tempf'raturo level. After once starl-
ing the catalytic proce8s, product
hl'at I'lln be rorlrculated or ulled to
hoat th~ Incoming stre:!!n. Where
fuel must be used to heat a stream
to a level necessary for sU1\taininp;
the catalytic roaction, IimitinR' CO!-lt
becomes the cost of heating the en-
terinj{ stream leBS the value of heat
lea ving the catalytic process.
Variability and concentration of
oxidizable material must be con-
trollE'd in the catalytic proceHS.
Since the prOC088 depends on con-
centration I. "fll, upper and lower
IimitB must be accommodated.
A conceTltration too low rf(llIire:i
that the stream be preheated; a
high concentration requires dilu-
tion. Where the limiting conclmtra-
tions lire of brief (a few minutes)
dura! ion, the hellt retaining' ca-
pacity of the porcelai n sup\,OI'lpd
catalyst automatically adjuBLg to
accommodate the variation. Oxygen
content of the stream lIel'd only ue
sufficiently in E'xcess of the i-Itoichi-
ometric requirements to assure ade-
quate distribution of oxygen to the
catalyst.
Prolong Cnlnly~t Life
ParticulateH of inOI'~,tllic matl'-
rials may not be a prohh'm when
velociti('.~ arc low. Wh~rl' the in-
organic particulatt's have an aur:\-
,~ive or attrition effect. upon the
cat.alyRt. the catalyst life is short-
ened. Where the inorganic partieu-
late~ fu.~e readily or arp in {'x-
j rem!'l:; hiR'h (jUalltity, then the
('''tal.I'st might become heavily
10adE'd with t.his material and th'e
catalyst life con8equently shortened.
Loss of catalY8t activity, which
rl1 of pure metal, 8uch as
mercury, arsenic, zinc, lead, etc.
These quickly stop catalytic action
hy permanently depositing on the
adivl' catalyst. Occurrence of high
cOllc('ntl'lltion of these Rub8tances
ii-l 1'l.lativcly rare in air pollution
control problem8.
For ai I' free. f "m particles and
metal containing vapor!!, a long
eatl~lyst. life may be realized. Some
inBtallations are reported to have
given over 28,000 hi', of service
without catalyst regeneration.'
!tocovery of Heat Value.
A, pilot run, before installing
full-scille equipment should be
madl', unless it can 1>e definitely as-
I'crtained by other mean8 that seri-
ous attrition or replacement factors
ar!' not involved.
As shown in the table, cleanup of
low concentrations of combustibles
will require additional energy. In
terms of heat, energy recovery will
bc negligible considering the cost.
Heat Content of Major Oxidizable Pollutantl in Air
Heat Cont.nt af Air T..np,
Bo,l. Mixtur., 8tu, leu. ft. RI.., F.'
Pollen., bOd.rla, dUlr,
fibers, .mokel
200 mg., ClI. merllr 11.000 Btu./dry lb. 0.099 5.5
Carbon monoxld.
1 .000 ppm. 321 B Blu/eu. ft. 0 322 18
3. 1 5 vol %, \4 LFl' 321 .8 Blu./cu. ft. 10.16 .565
Hllxano (normal)
100 ppm. 4,412 Blu./eu. ft. 0.44\ 25..5
o 315 vol. %, \4 lFl' 4,412 Dlu./eu. ft. 13.90 770
o 63 vol. %, !12 lFl' 4,412 Blu./eu. ft. 27.80 1,540
Hvdrog,," Iulf'lde
1 ,000 ppm. W6 Blu./eu. ft. 0.596 33
1 OB vol %, \4 lFl' 596 Dtu./eu. fl. 6.44 357
a. 100''i'o catalytic reaction (no hoar loss).
b low", flammability limit.
Benefits and advantages wiIl de-
pend on better public relations and
the avoidance of nuisance com-
plaints in the ~urrounding resi-
dential area. Since air dilution of
stack exhaUi~tB has long been used
to I\void neighborhood complaints,
It Is possible that reconsideration
and redesign of ventilation equip-
ment to include employment of
catalytic oxidation rather than air
dilution can result in:
. Savings in heating fuel and
air conditioning costs.
. A supply of heat from the
catalytic oxidation, which can fur-
ther reduce heating costs in addi-
tion to the primary objective of the
elimination of odorous organic air
pollutants.
A great deal of heat value can
be recovered for high concentra-
tion8 of combuRtibles which are
safely below the lower flammability
limits.
Step. to Follow in Combu.tlon
An approach to removal of odors
by catalytic combustion would in-
volve the following steps:
. An analysi8 of stack gases
and other exhausts to determine
characteristics and quantity of
odorous elements.
. A determination of those ele-
ments oxidizable in air and the heat
content per cu. ft" based on con-
centration.
. Estimates from a competent
manufacturer of catalytic burners
on the cost of instanation, life ex-
pectancy of the. unit. maintenance
and efficiency in heat recovery and
exchange.
. Preparation of cost analysis
on the basi!! of calculated C08ts of
operation, Including' investment V!!.
usable energy returns. Comparison
of this method with the appraisal
costs of other methods of odor re-
moval, taking- into consideration
advantages and disadvantages of
each method of operation which
might affect your situation.
. If the catalytic combustion
method appears to be the best solu-
tion, arrange for pilot-plant instal-
lation and ascertain the reliability
of all estimates involved, In addi-
tion to ob8erving the pilot burner
exhaust fo\' odorouR conte!! t.
Ab~orptioll Methods
Where odorous vapors are soluble
or emulsifiable in a liquid, with or
without chemical reaction, absorp-
-------
Odor Control by Absorption - Typical Scrubbers
L--
tion nwthnds may IJP :;lIitablp fo!'
odor ('ontrol.
Absorption i:-: a word 1101. with-
"'It it~ confusing irnplicati{)n,~. Ii
,lppllt':-I to a murt' or ]PS:-I unifl'rm
penl'lration of lh,' ab:-lurhent hy g-as
rn(,leclilt':-I allrt is not a ('oncept re-
:-Itrided lu liquid nb!'orhentq, In
this di~cug~iol\ howPvl'r. we will
limit t.!w di!'I'lIssion of abRorption
to the conventiunal proce~!' using-
liquid :\bsl1rhpllts,
Th!' fundaml'lIlHI ron'!'" ur int.'r-
phnlIP difTlI.;ion that J.
HOrpUOI\ pl'tlt'l'SH arp rnirly \\",11
knilli'll, 1'~qllJlihrium data, d,'l!'r'
Ini1l1lL101l or I1lImhl'l' of sla~l',~, di-
arnd('I'. lirniti1W \',.Iocity, are 1111
covered in standHrd t('xts HIiCh JlH
Perry, Sherwood, Hrown 1'1' BudgeI'
and McCabe,
On thr other hand specific, exact
klluwled~e in tilt' tlt,ld is not corn-
prehenRiv(', One of the mOHt
lroublesome applicil t iuns is the re-
moval of cxtremely small quantities
oC ai r ('ontaminantR that create
iJ(!ur nllisllnl'l'. According to one
1'l!nC~pt, if H >(HS is hig-hly sol ubI,'
t t t
i .' .~:
"
,.:,.
../' / J
---
in liquid, then its diffusion in the
lilJllid from the surface is relatively
P:I,~~', This would indicate that re-
sistanee to abRorption may be mini-
mized by Rpraying the liquid
t.hrou~h the gas, causmg good tur-
bulence on the gaseous side of the
interface (around the outside of the
droplets). For example, ammonia,
highly soluble in water, is readily
absorbed by spraying water
through a ehamber containing am-
monia gR~.
On the ot.het' hand for relatively
insoluhle g'1\l:\es (mllny odorous or-
gallk ('ompound!\ iC wllter is n sol-
vent) the reverse would be true,
"l'MiHtllnce of the liquid film lit the
il1terfw'e het.ween liquid and gaB
l'OntrolM mte of ahflorptlon, To
minimiz~' resistance, it is usunlly
n'commended thnt the gas be bub-
bled through the liquid to obtain
g'ood turbulence in the liquid phase
and facilitate gas absorption, For
this reason spray washers or
scrubbers have considerable diffi-
culty in absorbing low concentra-
t ions of some gases.'
ODOR CONTROL
.'
, ,
>. ~~
.~.\t .
"
, ,
:' .i~
,\,~
. , ..~ ?}
. ':\,J1
,. '
. '". . It .~'. .~
. ".:~~11
~J."'.'..~.~.;~..
\y:~
" >~,.,:'i~;:~~
,,. .~':. . :' .I~
;. .
. j' .'~.'i.~
Fh,J. 3. : ;~~~J
'Ilftplnoement
bo~.plot8
,
I '
.. ~ ~ ~
. .
,Wat." for hur(l~~'~~'" ,'J. "
, ''\
~~,
- ----
----
Commcr..ially Availabl.. Equipm.."t
Hundreds of method!' have been
devised to maintain air-liquid dis-
persal contact.
Increase in contact time or in the
number of separate times the air
encounters the spray zone greatly
assists the absorption of vapor but
performs an operation of diminish-
ing utility. Methods used vary
from the simple vertical spray
towers in single or multiple stages;
the ('IIIII'/\(!(, vet'tical tower; towers
pa('k,,(! with partition rin~!I.
ItHsdd~ rinl{l:\, spiral rinl{M, Bprl
Haddh':-:, hollow bullM, IwHcal puck-
I'I'R, h('xuhelix blockll, double spiral
\~yclohelix hlocks, pl'ismic pl\ckin~s;
(~(~nt.rifuga) or cyclone HcrubherM;
buhble and sieve traYM. etc, An
etf\cient scrubber (Fig. ~) uses a
perforated Rheet designed with a
layer of impingement baffies above
the sheet. Gas stream enters the
liquid phase through the sheet and
impinges against the baffle,
Height of an absorption tower
increases its efficiency, while cross-
-------
ODOR CONTROL
I~.OOO
14,000
Odor threshOld 000062 ppm
valerie acid
.: 12,000
.c
..
.~ 10,000 .
...
o
'"
:; 8,000-
o
Q)
L
c
::: 6,000
.
+-
Q)
£>
..
-
4,000
~ 2.000
'"
L
..
11 0" sl.:t',iliznlltJlI III"
']1< 11:1.1" 1'.:111'1" 1'1'1"111'1' di,.",hal"gl'd
~'I :11.' :-It"\4'r. ni"H'h:IJ'}[t' tlJ a ~(,\\'-
,I',' . \""1'1<1 I,la.l" ;111",\\''1' 1111' 1I,'\'d
J'II 1"'1,".11," 111';11111<'11/11111" Ih\' or.
I'"" .IV" "tlIII.' 11:'\'1' hl'I'1I "ull"I't..d
:1 d "11110/"11',01 1/, 11,1' wash wal"I'.
I'll lit" (111"'1" 11:11101 tll" p...,,,tlJlII'.1'
11,:11 ,J,:,.<';(I!l'l'd ga<.;t"; 01.".' 1:11"1"
1'>;' .'1'1' 11110 1111' "il" and 1'1"1.':11" al1
,I\!I)I' Jl!I!,.':lf1l't' ~d 0P1'1J Inanh()I\\~ or
,.i. ,', .'I'\\';I~'p ,.Ialll il.."')1' ~l1ollltl
1..01 1", '1\"'lllI"k.~d, Cal"l~ /Iliist be
:" i" II 11,,11 11";<"..,' .'.''1"11 hl,i ',g- ~"III'
I'"",' .:" 11111 nlpi't "t!,,:r ~IIllItiollS
Ih'l, \l'dl !"f';1( t .'Illd n'II';";(~ IhE'
',d'-'I" "1 ".'Itlll).! ,'omp\>lIl1lh t(l Iltc :11-
: t I I I ,"-. I ' ~ I " ""
,\1"(1. "'III,'nlll"1" 11'11"11 l'h\'~I,'al
:"d"I''':I. 111[1111'11 dll'ltIil'"I,.,':tc1'on
I" ill \'1111'1'" '011 alt~" rpti nn nlPt.hml;l. '
'I;) IILI! pI' "" 11l' (If I hp IHluI'1111S vns
III "'1111111"'111111 \\'i' h III";('!IIIIIIII (It'
..1"'" 1,1\.' I, J\ lil!liti1t~ ladol', 1'01'
;.11 pr~I,'tl\':11 1'111 ",' t'<"'; (/i'(IIIIH li;:11 it II
by phy~ical absorption is never a
prOCCBR whirh removes all odor~,o
In most ('aHCS \J::!C of washing
rquipm<,nt i~ Ruitable for the re-
,Tnt/val of parUcu]atl~ materia] (al-
thou~h not as effective aR I~Iectro-
sl:d,k pl"t'\'ipitators).
SI.,,," ,,, 1'"11",,, ill AII."rl)!;""
I '/"'11111'.'11 "II..~ill"('I"~ sholiid lake
!ll<' following- ~!.t'ps in r(ln:;id~~rillg
\\'a,.hirw. 1';;I\(kn,:I~!J'" OJ' sc!rl.1lthinjf
I""t hod".
-()<'Ii",' ,I Ia[,II,:lIory }WI'It!.lll'r
II lid II lIa 1,\'1.1' U", ('h"IIIi(';II~ di~-
l'hal'gl',J illtll Ihl' WII.~t.l' walnr. Cal-
"It/Ilk Ih,' t.ol:t/ 1'11/'11111'11 I :;1'\\ Ilgol!
1'111111'111 t 1"11111 all,\' 1'1,,111 01"'1":11 iOIl.
1I1"'"dlll)~ /111' "XIt;III';! .ylltl'lI \\ash
1"'1" ,j"y III' 1110/1111
-1'1'1'1'''1"(' S;lIl'ann' (in Wl'llillg" if pos-
sibl"1 lhat the <1Js('lIar).(e call bl'
madl' nlll'illj:( lhe I'l'nsnnalJle lifl'-
tinw III' tlit' propo~ed equipment,
M"IIY eqllipment manufacturers
will slIppl,\' pilot ur lahllt'l\l.ol'Y
"II',ipm"llt. whlrh dllplit-,dl' I.he e~-
,1'111 ials or t.hl'ir desiJ~'I1t'd ('quip-
1111.'111. )(1111" (,IlI'pl"lIl 1,111'1'11 '"1 l'lmbl
,d' npl'l'al'"Il, ,'ol'l"".,illll 1'lIlIditinnA.
:,", ,ij' I'. I'>:nlpill)'. "qlllpnll'lI1. ail'
1'"ldl:III' ':IP:tI'ily a"d l'l'qlli",'d
auxiliary equipment for supplying
exhaust movement,
- The odor evaluation of a.
washed exhaust is difficult to ap-
praise in a laboratory or plant area
due to the presence of plant odors.
For this reason final tests should
be made in an odor-free room and
by odor observers not conditioned
to normal plant odors.
- If satisfactory results are ob-
tained, compare an investment and
operating appraisal with other
methods of odor removal.
2 '9
o
Adsorption Method8
AdROrption is the phenomena of
surface attractions universal with
all subtances, In theory it is agreed
that adsorbed molecules do not
penetrate the atomic or molecular
t'onstruction of the adsorbent.
In acJ!;lOrption there is interaction
between the solid and gas. The
bond may be broken by moderate
elevation of temperature to drive
off the chemical1y unaltered absorb-
ate. This is physical adsorption
rather than chemical adsorption
(this discussion does not include
capi1lary attraction),
Control of atmospheric odors by
adsorption methods iR for all prac-
tical purposes limited to the 11.~e of
activated carbon as adsorbent,
Metallic oxide, siliceous and active
earth lype adsorbentR are e]ectric-
ally polar and have strong attrac-
t ion for waft'r. which is nighly
polar, Polllr :ulsorbents retain Wll-
tel' in pl'efl'I't'nce to mORt other VII-
pOI'R anrl therefore are im'allable of
nc!sorhillj( lion-polar or weekly polar
I'IISI'S (mo:;t ol'l.'an ic VII por:;) !leler-
livit.y from a moi:;1 atnliJsplwrl',
"divat.,'d ('arl"111 is elt.ctrically
lIoll-pnl:1r IIntl ('on~("pl"lItl.v (!l\p!lhll~
,d' j)1'P("1'I'enlial IItI~ol'pUon of or-
galli\' IIIHft'ri:d. PI"('vio,,~ly I\d~orht'd
IIllIistlll"e will hI' tlisplal'pc! from the
earholl surfaec as or~l\nk arids and
\'!If!ors art. aclsol'bt'd,"
/\ n ad van tag-t' of using activated
e:J rlJOn is i t !lU~OrbR all type~ of
orlOI':; unc!er almost any condition.
It ean hI' IlSI~t.1 without making a
l'arl'l"llI nnnly~iR of odor contmt,
I'ro»1' 1'1 ios of gases and vapors and
tt1l'ir I'P11'ntivity by activated car-
\"111 are nvai1ab\e,'
]';qnipment ReJection generally
d"lwnlh nn l'equireml'nt.R for total
":Jpacit,\'. allowahll' pressure dl'of!
:llId :-;pllre requirements, Over-all ad-
,<.;111' pI 1011 I'flki"I1I'Y nf activat.ed ca )'.
\11111 is pmctica]ly 100% for vapors
hal'inl{ Il high l'elpn1ivity vulile and
-------
remains so until the amount of ma-
terial adsorbed is about two-thirds
ot the retentivity figure independ-
ent of moisture. Care must be used
in replacing the activated carbon I
filters prior to the saturation point.
Once carbon Is saturated, odor will I
continue to carry through the
filters.
S~rvlre Llle 01 Ad.orbeD"
Service life of an adsorption sys-
tem, using activated carbon, for
purposes ot replacement may be
computed trom the following form-
ula (Fi~. 4):
Time of eervice life (hr.)-
6.43 lO)ISW
. M II
Where S - ultimate proportion-
ate ssturation of carbon or frac-
tional retentivity; W = weight of
carbon (lb.); e = fractional ad-
sorption efficiency; Qr = cfm. of
air processed by adsorption equip-
ment; M = average molecular
weight of contamination; Cv =
ppm. of contaminants.
The following are the properties
of some atmospheric contaminants:
Acroloin
(heated ra~)
II~'une
Mol.
Wlt.,M
ft6
Odor
Rete" Ii vi ty Thrwbold
S CODe., Ppm.
0,16 1.8
86
o 16
030
0.36
Alrooet
odor 1-
0,28
0.00062
Phenol
Valeri£: acid
(body 0<10')
94
102
With heavier mO]t'cular weights,
when concl'n tration exceeds about
2 to 5 ppm. of air stream, service
life of Ilrtivated carbon is greatly
diminished. This calls for frequent
reactivations and correspondingly
high operating cost.
Equil"nrnl H.ed With Carbon
One satisfactol'y arrangement
for activated carbon is in small
cylindrical caniaters where 6-14
mesh carbon is held between con-
cl'ntric perforated cylinders. Each
c~anh;ter holds ~-11lb. of carbon and
each ('an handle 25-36 cfm. of air.
A numher of canisters are placed in
:~ manifold. For large air flows,
<,a rho I! is held in thin beds between
.O<'I'pI'IIt! or perforatecl sheetR of
l11<'t:lI. Air must bp reasonably tree
of :;olid aile! liquid pal'tlcles.
(~l1rIJ(Jn ('an is leI's have proved
"111'I'I'.,.,.,flll ill 1'1'<,\,pl1tin~ the ('!I(,1I11I'
. . ODOR CONTROl
How to Inject Odor- Maskino Compounds
Odor moskinO
fluid
Gear pumps
e.T.OPll
Clloin driven shaft
of a tenacious garlic-sulfide stench
in a pharmaceutical plant, Installa-
lation consists of 503 canisters each
with 1.6 lb. carbon, handling 12,000
cfm. Carbon is reactivated every
six months.
It has been observed by Turk'
that the upp~r practical range for
activated carbon application (2 to ;
6 ppm.) is far below the lower
practical range for catalytic com-
bustion 0,000-1,500 ppm.) and
that this void has not been stressed
in current literature.
A great number of industrial
plant stack exhausts emit odors in
quantities between these two
ranges. In this /lrea consideration
should be given to odor masking
and odor counteraction.
Odor Masking Methods
Odor maskinj:f is the pl'ocess of
eJiminfitinJ{ the percer-tion of one
odor or a group of odol's by super-
imroslnR" another odol' or a group
of odors to create n new odor sen-
sation, preferably plensant.
Odor control chemicals used for
masking purposes are those aroma-
tic chemicals and their byproducts
which fire derived chiefly from ~yn-
thptic aromatic chemical 'manufac-
ture. A maRking agent does not
alter tho composition of pre-exist-
ing odor. When superimposed It is
st:!lecterl by the nasal perception ap-
pal'lltu~ as long as there Is sufficient
Stock No. T
140,000 ctm.
Stock No e
140,000 cfm.
Stock No 9
170,OOOcfm
e.TOph.
6.70Ph.
Rhodia Inc.
Fig. 5
presence -of the masking odor in
the air stJ'eam.
Organic odor control chemicals
are numerous. Each type differs,
since some may be malodorous and
others sweet or sour, fresh 01'
musty. Examples a1'e vanillin,
methyl iononea, eugenols, benzyl
scetate, phenylethyl alcohol, helio-
tJ'opin. Only by selected manufac-
tUl'e and measurement Is it possi-
ble to obtain an odor control
chemical suited to a particular
masking or odorization problem.
Many odor nuisances fall into
similar patterns for similar opera-
tions in the same industry; odors
from a Rulphate pulp mill. from
rayon processing, asphalt blowing
and many of the chemical pl'OC-
esseil. In many cases, where the
basic charactel' of the operation is
known, a sample of the odor efflu-
ent i8 not necessary to establish a
suitnble odor masking or modifica-
tion ('ompound.
In spite of the fad that all nor.
!TIll I people cnn perceive odor:i and
many people find some odor., aJ.(l"ee-
able, odor masking (and in its
turn, odor counteraction) is not a
field for amateur experimentation.
Peorle sntTering from brain
leHion!l, injured o!factol'Y nerves 01'
obstructed nasal passaRes may be
anosmic. Substancell of different
chemical \:onHtitl1tion may have
simi1u odors. Ql1ality, 1\3 well a8
the 8trcIlRth of the odor, may
-------
ODOR CONTROl .
chang£' on rlilllt.iol\. TIll' S£'I\!\l' ,If
IImell is I'apidly fat ig-I\eo. Fatig-ue
(or one 0001' willl10t IIlfert the per-
ception of otlwr oissimilllr ooors
but may int£'rf(,l'e with th£' pP~'cpp-
tion of !dmilRI' 0001'''.
Formulation of 1\ preferrp.! odor
C'ontrol meoillm ]'equir2s 1\ great
oeal of oeliC'ate osmic annly;;is and
technical know-how, Completeo
formulation must include, il\ aodi-
tion to maximum odor fltreng-th ano
optimum odor quality, Rpecial prop-
erties of chemical stability, laRting
power anri physical form.
H..w 10 A"I,I) C.."',Hmnd.
In ('ompnl'iROI\ with th,' bhor:l'
tory t'xJwrit'III'I' n'qllil'!'d jl> fo,'mll-
lale 0001' ml1skill~ ('omlllllillds, np-
plil'alion is rt'lalively simpl(' and
does not n'quin' ('xc!.'ssi,,!' C'apital
i nve!ltmel\ 1.
For ('('rtain processes, such as
di!('ester operl1tion in thr kraft "111-
phate pI'IJn'ss, or ('ooking meat
scraps :In.! honcR in rpndering-
plants, odor maRk ing compounds
are addeo oil'cctly 10 thp C'olJk. This
method of trpatment requires no
investment in mechanical equip-
ment. althou!!h the trend is toward
addinl(" thp maskinl(" compoun,ls
antomatically with proportioning
pumps. Concentrations may I'!\nge
from 10 to fit) ppm. based on the
weight of th,~ pl'ucess chnl'l("e under
tl'patm£'nt.
OrlOI' masks ma~' 11 Iso he api>lil'd
hy air or prl'ssllrp atomization
(through propl'rl,v desi~~ned spray
npzzles) of a dilute disp.'rsion of
th\' material into the stack from
\\'hil'h mallld(,r" :11'1' normally dis-
charged (Fi" f»), If 1he odor
maskinl!' ag('lIt is watt'l' sohlb1e it
c:ln be diluh'd with \\'al.')' to most
pructicnl dillit ions, uSlially 1 to 5(';.
Injection is IlslI:1l1~' at a point wpl1
hplow th!' top of 1 hI' ,slack 10 HSSllrl'
good mixinl{ wil h 1111' I'Il1u\'nt
vapor,s.
An oil-hasl' mn"king agpnl may
hI' spl'inklt'd nlonA' th£' Hhol'l'line of
a Jagoon or pourl'd 011 tl1., liqllirl
"lIrfal'1' of the 11ll{00n whel'l' it will
,'ipread most readily. Normal
evaporatinn under the hl'at of t.he
sun vAporizers the mask C'onlinu-
oUHly :l!ong Ihl' pntil'e arl':&.
1'...... 0011 CO"- of Mo~ki".
Ma:11lp.
Odo\'imrl ri(' nwl hod:-: fo\' tIi~ter-
III i II.. t.iOJl of odo\' "Irl'ngl'h of 0(101'-
Oll~ chplI1icalH ha \'P 1)('('11 describeo
aile! I.h., I'xJlI"l'ssioll~ of St'pnt. Unit,
S(,(~'lt V;tlIH" Cp." <;;"(~nt Valne C:1-
tahlislwfl. A met/lod for dctpl'min-
ing- masking str('lIgth is expJ'dned
by Trcmain."
(;0"1'01 Vi" 0<10. Moskin«
In preparation for odor maflking
con t \'0] take thl's(' basic ;;teps:
. Make an analysis of the toxic
mat.erials or lack of toxic materials
in ppm. and total cfm. from fltack
I'xhallsts. Check with the local
public health officiaJs or air pollu-
tion officers to oeterminc whether
dispenm] ,lf t.he!Oe m~terjlJls is well
Iw]()w Ihl' minimnm permissible
h'vel ill till' slll"rounding' area.
~ lJo not attl'mpt to fOJ'mltlate
masking- .'ompounds unless you
ha\'1' had !'onsidemhl!' and Il'ng.thy
('xIJI'rience in odor ch('mi:'\t.ry.
. E.~tahlish quant.i !.iI'S of ma-
ttol'ial used in proC'I',~S, pal'1i('ularly
Ihl' orlorou:'\ mlltprials, anrl tcm-
)1I'I'nlul'(';; of procps,~ and :;(acl, etftu-
('II/. Call in II ('ornpptl'l1t m;ll1l1fac-
1.11\'('" of masking ('ompound~ and
di~!'IOSf: :11'1 milch info1'mation I't'-
j.(lIt'dil1j.{ the pro!'I:SS II:, is pt'rmis-
~ihl(,. Jlavl~ him OhH('rvl: the mal-
odors from It!\' ;;tal'k I'xlillust IIntl
ill th(' .~urrounding an'a.
. If th.. rnasldl\g' compouno iH
to he H~erl as an additivp, ('stablish
in the labol'at01'Y that the addition
hus no effee!. 011 t he pro('I'S~, I f the
maskil1l{ \'omponnrl iH to be applied
t II t.hp ;;ta!'k exhaust, it. is advi~able
tll pf'rflll'm n labllralo1'Y or pilol.-
plallt I'xIH'rina'llt. with thl' product
(II ..~1ahlish rllt.io~; which will not
1'<,,,111 ill 0111 inl/'lis., ..lnUl'ut. ])1'\1'1'-
miue thar Itll ofTenflive conclusion
might not rmmlt in the final com-
bination IIH a consequence of odor
incompatibility,
.Infltall equipment as pre-
flcribet:l by the masking compound
manufacturer, This is ordinarily a
flimple installation that can be
made by plant personnel and usu-
ally involves only a source of air
and a calibrated spray nozzle.
. By means of an odor jury
make area surveYfl over a period of
fleveral days. Take into considera-
tion known factors regarding air
inversions, tupoj{I'aphy and wind
movements. Cat'e should be used in
buildin$t up to the required con-
centration, flince an excess may 1'1'-
flult in ('omplaint.~ in the surround-
ing area re$tarding new odors,
Odor Counteraction Methods
Zwandpmaker was probably the
first 0001' researcher to study the
counteracting effect of two dis-
similar odors,'.
The principle of odor counterac-
tion is separate and distinct from
t~e psychological effect of odor
masking. In odor masking strong
od(Jrs teno to mask weaker ones,
H the two odors are of about equal
strength a blend of the two is ob-
served and both can be identified,
If one is considerably stronger
than the othel', it alone as a rule,
is pcrcpiverl,
In odor counteraction certain
pai rs of odol's in appropriate rela-
tive I'onl'entrations are antagonis-
tic. When the two are sniffed to-
g-cther both odors are diminished,
Various pai rs of ~ounteracting
odorous substances were recorrled
by Zwnademaker in 1895. He used
a rlevicl' to individually introduce
int.o eithrr nostril ooorous sub-
~talH'I':-: in a ratio of quantities re-
quired for counteraction,
Many 01111'1' workers, inclurlinj\'
1\101l1'ril'll' :Ind Bachman, have made
similar Htudies in which It was pos-
sible to I'ornpl'nsate t.he olfadory
elfeet.:i of variollfl chemicals to a
point of total odor disappearance
or flig-nificantly close to the point of
total odor disappearance, It is a
known fact that in the group ben-
zene, toluene, xylene, pseudocumene
and durene, combinations in the
correct proportions from this group
can he produced which are almost
odol'lesH. Many materials are thus
available for odor counteraction, in-
duding the essential oils,
-------
Odor counteraction, as developed
to date, is based on significant work
done by early experimenters. De-
velopment of odor counteractants
is a pure matter of Edisonian re-
search and many years have been
spent in this delicate work by com-
petent odor researchers.
Impf!lu. Come. From Air Coadltlonln.
Odor counteraction was first ap-
plied in the air conditioning indulI-
try. Household products such as
oil cloth and rubber, polishes, wax,
paints, inks and insecticides are
:all antisocial from an odorous
standpoint.
The air conditioning industry,
in a combined attempt to improve
.>! mospheric control, was faced with
a serious problem. Attempts to
dominate these odors by the use of
:;asRafras, wintergreen, citronella,
pine, lavender and other compounds
were not satisfactory. Commercial
use of odor counteraction thus de-
veloped in this field. Since air
frellhnesll was desired, instead of
recognizable IIpeclfic odor types,
odor counteraction with a sense of
frellh air was developed by intro-
ducing traces of the chemicals
found in outdoor plant-life areas
(chlorophyll). This work wall ex-
tended to the iudUl~trial odor con-
trol fidd.
All houJ{h an industrial process
may he lIimple, industrial odorll
l'''min~ from t.he process may he a
l'omp!t.x group of odors. It is un-
usual to obtain n specific odor from
1111 inrlulltrial process stack. Even
when this is the case the odor may
combine with transient odors in
the surrounding atmosphere. For
this reason industrial odor counter-
artant formulations, although de-
signed for specific odor descrip-
tions, may contain complex groups
of odor counteractants.
There ill no chemical method
known for the determination of the
dTediveneRIl of odor counterac-
bllltll. Effcctivenellll can be deter-
minprl by actual odor perception. In
t h(' III:;t analysis this is the criteria
fllr the effectivenesil of nny odor
ahatcmenl. mpthod.
n..w II..... Coulll"ra~llon Work?
Odor count£'racllon dealM with
m<.!I'('III..s of odor. For prnctlclLl
JIll rpWH~1i un odor ill always 1\ gall
rnol('('ulllrly disp(!rlwd in air in suffi-
cient concentration to be above the
threshold lev(~1 of perception. For
I hi~ n~ason odor counteractanta are
How .to Inject
Ai,k.m
Odor Counteractant8
FIg. 6
Odor countoroctont
3te" Qolv. pipe
liquid line or ,.,
tYQon tub!nQ
Counteroctont
storOQ. drum
/'
most effective when vaporized and
combined with the air stream by
molecular dispersion.
Stream exhaust can be held to
the ground by air inversion, verti-
cally dispersed, or horizontally dis-
persed. But the odor counteractant
is carried with a malodor and Is
noticeably effective until the odor
is dispersed beyond the range of
perceptibility.
Applyln. CouDteraet1on CompouDd.
Odor counteraction Is partic-
ularly effective against multiple
odor sources. There may be liter-
ally hundreds of sources of odors
within a plant proper: main stack,
ventilation of process areas, vents
from storage tanks and chests, spil-
lage areas, wet walls, stock pl\es,
all contribute to the total industrial
odor load.
Odors from this source expand
by molecular dispersion In a rough
rnngo from {) to 1 until the odor-
OIlR pool 1M taken ovor by J{eneral
alt. movement. Further dispersal,
mixinlC and dilution, takes place
durinle the variAble air movements
until the characterilltic odor of the
plant is perceived in the complaln-
inle IIrea.
Air Qun'
Stock
Compreued air
~8" golv. pipe
air line or
alrho8e
Odor .ouree
Odor counteractants are vapor-
ized by atomizing the counterac-
tant into the ai:- movement or
stream by means of a calibrated
atomizing nozzle. These vaporizing
points are usually located in or near
the stack exhausts but may also be
located at the plant roof top and in
the vicinity of most odorous effiu-
ents (Fig. 6). This provides ver-
tical coverage from the bottom to
the top of the odorous pool leaving
the plant.
Counteractants mix with the
odorous air stream by molecular
dispersion and air movements and
are designed to follow the physical
behavior pattern of the odorous ele-
me,nts. Some odorous elements
disperse beyond the limits of per-
ceptibiJity rapidly, others are tena-
cious and do not disperse horlzont-
aUy or verticaUy a8 .qulckly thus
creating special control problems.
Odorolls discharge from kraft
tlulphate pulp mills, probably due to
!lame microscopic particulate for-
mation, continue to tra\lel nnd
vaporize for miles. Specific odor
counteractants have been designed
to follow these physical dlRpersnl
patterns.
Vaporization of a liquid odor
-------
ODOR CONTROL
counteractant is accpmplished by
clean compressed ai I' (approxi-
mately 2 dm. per gun). TIll' liquid
odor coun teractan t is stored in a
prrssurl' drum I\t a convenient loca-
tion allt! frd throug-h small connect-
illg" lines to thl' vaporizi ng- lIozzles
by air pressure.
Operation is Hutomatic and once
the installation is i\et up and bal-
anced requirl'~ littll' mllilltenance
l'xcept. fo,' weekly filling" of the
pn'ssure containers. Odo!'ous
sOllrcrs vaporizing at. :1 continuous
rate are trl'ated continu0usly. The
int.'rmillent II!H'ration of 1 (,Iir{
valv.'s llIav I,,, trl'at,'d dllring" tll<'
blo\\' oil' V.I' automatic valve" which
operat., arcIIl'(ling III 1.111' ! il1\l' of
blow oiL l';qllipnH'nl ii\ "asv to in,
stall :111(1 no alt.'ral ion,s a 1'1' l:("lllin'"
to proccs!! e(juipmenl. Nil down
time ii\ reqliired for iJ\.stallat ion.
(:ollnl('raction: No (;urc-AII
Since then' is 110 chemical ('tIt'd
on the odorol19 efflucnt. o,]or
counteractants should not I1t: 11::-:l'rI
in cumhination with hig-hl.v tnxir
materialH ul1ll'''s the dispt'r:;al rlltl'
is we]1 hel(lw t.he maximltnl JH'rmis-
siblt! ]!'v('1. (;(!neral method (If al'pli-
<:ation hils the imp'.rlan!. pradical
:H!vlllltagt'::-: of very little illitial
e'1u i l'T!lpn t cosL.;, 11 I' I-d il-~ih!(' :,pace
requir.'ments, and greater freedom
frnm th(' necefl~ity of confining- th('
atl1l,),'phel'e intI) a I']')Sf' spar'l' ro,'
II'" a 1 !~ :\'111.
'1'11,'1'1' i,,,; III) ul1in't'sal "dill"
"I1\II1II'r:I('I:I>lI, Odol" "f>llnt('r:I"tion
r"l"TIlldas an' ,],'~ignl!d f"l" 'I,,'~ifi/'
"1'"11':: "f ,1I1"rs. Odl\l" "l\llIlIl'r:\I'
I'", i ,::IIlal i"n~; .';bl"iI'] I", tn:llh'
I, .. "I"'l'i:dist who ,'an di::I'I'imi.
11:1~1' 1,0>[11'('1'11 oc]l.r," and (,,'tim.'!t(.
III" in I "II"i Iy (lr ('on('CIl t r:11 ;":1 ", i,l-
.;, '" I'd ill Lhl! pl""hlNn
,\ 1111'11'1:]1 :1 i,s 1':11 b.,1' (':1,'-,1' 1'"" I bl'
1":"']1',1 11(1"1" 1':' I' '1IIin',] 1",,,' ,!It-divt'
tq"'1:I,llt'l\ "\:l,\' ,,11111 ('\'11111"1 \\'1:1111
11,,;,'d I II I II 111.'';\ 1'1:11 \\ jll'l, :\ 1',';1--1 (11'
inJuHtrial ~tackH for thc cont.rol of
atmospheric odor pollution ;;hould
he lion toxic, nonallergenic, non-
"ammable, lIoncorros ivp, ch~~mically
inactivc, pconomically fpaflible and
Hhoulrl III' {>ITl'ctive in the lahora-
tory alld in the field.
Odor ('ollnt<,ractant.~ cannot he
I'';l'd for thp eontrol of llartkillat.e
material. In extreme examples,
where tilt' air-borne wilstl' nf an
indu;;trilll pro('c;;,; lTIay contain
dW1t, funH', ('ondl~nsable vapors and
IInconr!('n,;:lhlc g-ases, t'ntraill('d ma-
t('rial should lw scruhbed to remove
dust 1IIId ;;oluhle or ('olld('!lsable
VII pOl':; ; t h{>n pasfled t.h roug-h an
,'I('ell"O"'Hlir~ pI"I'/'ipilator to ('ap-
tlln' l"ullll' :ru'n', R. W., "The ChemlcB.:
Son,"s," 2nd o<1'J chaptor XII, London,
J,""'Hlrd lilli, Lto" (1951),
4. Grilli.... C, W.. "Ollor Pollution From
Tho Offklnl'H Vlowpf11Ilt," Ame-rlcun Sn-
('I"ly tor 1"',lInl{ MILterln'" PhllnlleJphln
I'll, )lr"I)"&nl #IOr.A (1%4), '
r.. Ant,,". II, H,! ,"",r"o' "f Air Polluti""
Coutrol ARM". "I UJlJ{fI or AI pllcabl1lty of
(~ltlnlyllt~ li'lIlIln BlIrIlOI'M," vol. 6. no, ;t,
Nov, 1 fI r, !i.
Ii, Turl{, A" "Odor COlltrol Mf'thodM:
1\ f 'rHle..1 HI'vlf'w," ahH1tnl('t, Jlnnul.1l mH6t.
III~~ or 1110 t\ Hh'l'k/i II Sodj'l.v fur TOHthig
Malt'lllll:-., (~III""J{jl, III. (.r1Jnl~ 1f)rt1).
7 [\1('( 'on! II lid \Vlth"rt(l,Kt, "()clnr~
'lhYHlfilfll~,V alld f 'u(\11 01," Mcf:ll\w-JIIII,
Nl'w Yllr!< (1~'1!1). '
H, .'Alr Ct",.'it'r\",tICJII ]1~nf.;'ll1eerlllg'" Con.
lit)!' NtlJ{III~I'rlll~ ('''l'fJ (19fi:\).
!I. Tr",,,,,lnt>, lI, K" rell'I'!. vol. 31, Aug"
PI', 14IA-1-13A (IU:.-I),
I 0, 7.W"'lnl~n'ak"J", II., "1)10 Physlologle
do" Orlich.," Lelpzll{ (189:».
IIPrint.d in USA-.,#1B9"
Reprints Available
Reprints 01 Inlt 12-page report
are available at 50~ each. For fast
,ervice ute the Read..r Service po.t.
card inside the back cover of thjs
jsouo. Simply check off Reprl~t
No. 98.
-------
CONTROL METHODS
OF SULFUR OXIDES
FOR
FROM
THE REMOVAL
STACK GASES
.1. E. Sickles, II
.I.W. Sullivan
INTRODUf;TION
The control of oxides of sulfur is a problem
that is world-wide. Strict antipollution
laws are being considered in various nations
of Europe, in Japan, and in the United States.
It has been suggested by Japan's Living
F.nvi ronments Council, an advisory body of the
Ministry of Health and Welfnrl', that the
maximum allowable concentration for S02 in the
atmosphere be set at 0.05 ppm. Levels of
0.15 ppm. as a 211 hOllr averag(' and 0.29 ppm.
as a ha If-hour averuRe have been set in West
Gennany. Tn France the Mi ni s try of Indus t ri es
h.JS fixed the allowahle level of atmospheric
".(12 at 0.39 ppm. (I) The U.S, Pllb]ic lIealth
Service has recommended that the S02 concentra-
tion for a 24 hour period not exceeiJ 0.] ppm
more than 1% of the time (2).
It has been estimated that 29 million tons
of SO. were emitted into the atmosphere
wi thi~ the Uni ted States in 1967. If the
present growth rate continues and control of
S02 is not enforced. between now and the year
]990, the U.S. will have emitted the
equivalent of 1/2 trillion tons of sulfu]'
in the form of 502 into the atmosphere (3).
For example, a 1000 mw. plant emits 600 tons
of 502 per day or the equivalent of 300 tons
per dDY of sui fur or enough su 1 fur for a
producti on of 900 tons per day of su Iflll'j c
acid. If all the S02 emi.ttecl in the II.S.
were convert ed into sui furi c add, the amount
produl'('d (24 mi 1 lion tons) \wuld he con-
siderably more than the present II.S. con-
sumption (22 million tons) (tI). If only one
third of the total emission were recovered,
this would satisfy ahout two thirds of the
demand for sulfur by the fertilizer industry
(5) .
111e largest single source of SO') is the com-
bustion of fossi I fuels for pow~r generation
which contrihutes 46'1, of the total. Com-
bustion of fossil fuels for other uses con-
tributes anothf:'r 32"., givinR a total of 78~.;
of the emissions coming from fossil fuel
comhustion. The remaininR 22~, of the emissions
-~------~--- ---...._- ..-- ---. .,- ".-..
. --- -... .... --.
.J.E. Siddcs. II is a Chemical l(n/.:inl'\'I'.
cllrrently At tl\(' Un1v~rl'lity of North CI1ToHnn.
.I.W. Sul.llviJl1 IH 1111 Air PollutIon COI1L.rol
Jo:n~lnl'cr, Kl'l1tllcky Air Pol I lit 1011
ConI...>! CommlsfplI
P A . C . gl' . 31. J 2 . ]0
comes from ore smelting (12%), petroleum
operations (5.5%). and other mlsce llaneous
sources (4.6%) such as coke processing,
sulfuric acid manufacturing, paper mi lls,
coa] refuse banks, incinerators and others
(3) .
There are three general methods of reducing
the amount of 502 released lnto the
atmosphere: desul furizat ion of fuels, process
modification, and fluc gas desulfurizatioJl.
1~is paper will deal with the present
status of techni4ues for the removal of
5u]fur oxides from flue gas. This is an
area that is receiving considerable
attention at the present time, particularly
frool the power industry. Their problem
is unique becallse of the low 502 concentra-
tions in the tremendous volumes of their
flue gas emissions. A power plant using
a 3.5% sulfur coal will have a S02
concentration in the stack gas of about
0.2 to 0.25% by volume (4).
Most industria] sources such as ore
smelting, refinery operations, and ~raft
paper mi 1 Is' 'emit concentrations which
are relatively high when compared to
combustion processes and in many cases may
be treated using a standard sulfuric add
plant. For example, in the ore sme]tering
industry if the S02 concentration in the
gas stream is above 3% by volume then it
can usually he fed directly to an acid
manufacturing plant. In the United States,
17 (which handle 42% of the ore concentra-
tions) out of 35 su]fidc ore smelters
arc recovering 802 or sulfurlc acid (6).
111e scope of this paper will be further
limited to the area of methods for
removing the low concentrations of sulfur
oxides found in stack gases from fuel
comhustion. Many of these methods could
be applied in other areas where very low
concentrations of sulfur oxides are emltted
and where there is a necessity for control
of these emissions. Most of the current
work in this area of S02 control is aimed
at the pow~r industry.
Nucll'ar pow('r looms in th(' fut.ufe as the
prohahle replal'(~n"l~nt for rossi I fuel-
h\lrnin~ pow('r plants. The N'atinnal Coal
i\ssod at j on i n.l i C:ltl'S that coal pl'i ces
-------
Control Methods for th(' Removal of Sulfur Oxides from Stack Gases
can absorb pollution control costs of $1
per ton and still remain competitive with
nuclear power (5). The economics of
the two governs which will be used. Any
additional expense such as that for
pcllution control levied on the fossil-fuel
utilities pushes them a step closer to
obsolescence in the shadow of nuclear
power.
Tahle I illustrates the projected increase
in fossi I fuel consumption to the year
200(). If one considers fuel oi 1 allJ
coal tu have a 1 and ;'.0 sulfur content,
respectively. thell the hurgeoning threat of
sulfur Dxides to th(' atmospher(' becomes
mon' cv 1 Ul'n t '
the trade name of CAT-OX (8). The only
successful marketing venture to date was
announced in July 1970. A demonstration
unit is to be installed at the Illinois
Power Wood River generating station on a
100,000 kw. generating unit. The $6.8
million project is to be operational within
two years (9).
The process invglves passing the hot
flue gas at 950 F from the boiler through
II high temperature electrostatic precipitator
to remove 99.5% of the particulates. The
gas is then taken through a catalytic
convertur (using a catalyst such as vanadium
pentoxide) where the S02 is'converted to
'I'al>ll' 1- Anticipated Power Plant Coal and Oil Consumption (7)
l%h
1970
1975
1980
1990
-- ~).~--_.J
6
<;_u:.!..L~!Q -- !.QJ!,<;.-
2t>7
:\75
550
750
875
800
.--.-.-..--- _.
.--.------ ------..
oil harrels xl06
. . ---142' ---- -_.- _on
175
225
240
250
230
11
CONTROL MFT'IIO[)S
Numeruus m('thoJs for control of the oxiJes
of slll fur have heen proposed and many have
reached th(' pi lot p1allt stage or have shown
,'ow,iderahlc promise. The majority arc
expensiv(' anJ few have been tried on large
plants, 'I'he}' RCI1l'rall,v liS!' eJlher an
ahsorl'til)J} or ads(Jrpl ion techniqll~' flll lowed
h" s"me m,',II\S uf ~;ep:lr"till~ thl' sorhent
fl'uln the' fllll' !:1I~ for I'l'!(elll'rut i Oil, aile
l'x,'C'ption is the' l'at:dvtic oXlduti()11
t (,,'hll i que
A.
I:atall'tic Oxidati",\
1.
tAT-i)X: I'h(' most pronlilH'nt process in
tht' arcu of ,'atalyt i c oxidat i on wac;
developed hy the Monsanto Company
in conjunct ion with the l'ennsylvall1<1
r.l(lctrlc COj1\pant, Air PrehclIter Company,
and Rcs('arch-Cottrcll, A small pilot
plant was constructed at Pennsylvania
[]ectric's Seward generating station,
This pilot plant proved sllccessful, and
Monsanto Company ;1nd Metropolitan
Edison Company constructed a prototype
nlant lit Portland, Pennsylvania. This
plant is presently in operatiun,
Monsanto is trying to market this process,
which is il!tlstrated in I'lgure I, under
..
503. The gas is then passed through the
boiler economizer and air preheater for heat
recovery. The 503 and water vapor present
in the gas stream are combined forming
sulfuric acid vapor at a temperature still
above the dew point for the acid. The gas
is then passed thruugh an absorption tower
(using sulfuric add as the coolant) where
the sulfuric acid vapor is condensed. Any
acid mist which escapes from the tower is
raptured hy a high efficiency mist eliminator
(8) .
Thl' process has lIet'n :II> Il' to rCI1IOVl' U 11 the
fly ash, 9()~, of the S02. anu 9~,S'\. of the
sulfuric acid produl'I'd, It has proJul'('U
a sulfuric acid with ;III average eonct'ntra.
t i on of 8()~" (8).
Monsanto estimates ,a capi tal cost of $25 per
kw. above that for a new power station
for the unit. They estimate that the
hreakeven point on a lOOO mw. unit operating
at 80% load and burning 3% sulfur coal
wou Id be reached if they received a netback
price of $13.50 per ton for 100% acid. If
5% sulfur coal were used an acid netback
price of $8 per ton would have to be
real i zed (8).
The process has several advantages:
-------
Control Methods for the Removal of Sulfur Oxides frolll Stack Gases
High Efficiency
Electrostatic
Precipitator
9000
GdS to
Stack
9500
t
6500
4500
Hot Fl ue Ga~
from 130i ler
H2S04
H2S04
I'igun' 1.
Cat-OxS
I.
I tis n' I a t i v d y simp il'
2.
KIYOIJRA-TJT: A simi lar process, the
Kiyoura-1'IT process, has heen tested at
the 1'oyo KoatslJ Pert i Ii zer Plant in
Omuta, .Japan. This project has been
installed since the two O.IS row. test
units were stopped in 1967 (1). The
process is illustrated in Figure 2. In
this process ammonia is injected into
the gas stream just before it enters
the air preheater. It reacts with the
S03 to form ammonium sulfate. The
ammonia must he injected at this point
to avoid condensation of sulfuric acid.
The solid particulate, ammonium sulfate,
is then collected with an electrostatic
precipitator or with bag filters and is
ready for shi pment as fert i I i zer (4).
2.
No recycling stcp is invulved.
TI1l' fllle g
-------
Control Methods for the Removal of Sulfur Oxides from Stack Gases
1 .
advantages of simple regeneration and
of sulfuric acid being obtained directly.
All three systems. however, require
large amounts of make-up carbon.
RI: TNLUFT: The most prominent of these
processes is the Reinluft process
J~veloped by Reinluft, Tnr.., Essen,
(;~. rmany. The process, for whi ch
<)50. efficiency is claimed (6). is
presontly being tested on two 10 mw.
units in the Ruhr Valley. Reinluft,
Inc. n'cently signed over I ts rights
to the process to Chemichau-Zleren Co.
( 1) .
[n the process. as i) lustl'ateJ in Figure
3, the flue gas is passed through an
- --- _u ----.. -
--.- ---------
The process is estimated to have a
capital cost of $17.80 per kw. for an
800 mw. power plant using 3\ sulfur
coal, and an operating cost of $2.45
per ton of coal (6).
The process has several advantages
(4,6) :
1.
A desirable by-product in the form
of concentrated sulfuric acid is
produced.
2.
Cooling of the stack gas is not
excessive, thus it maintains
adequate buoyancy.
to Stack
------------_. -------------
Air
210 0 F
-------
350 0 F
Adsorber
Coal
N2 or C02
Coal Ash
f'iRure 3.
Rei n Juft 10
. - ----- ------.------ - --------
3.
Carbon steel can be used in it~
construction.
. ------
electrostatic prl'cipit can then be ra~st'd on to a
:, t andard su J furj c lIeI d manu facturi ng pI ant
( 10) .
210 0 F
Heat Exchanger
50% S02
Activated Char
4.
It is not necessary to incur the
high cost of activating the carbon.
The disadvantages are;
1.
The system is prone to develop hot
spots or areas of uncontrollable
oxidation.
The recirculation of large amounts
of carbon is expensive.
2.
3.
The costs for make-up char are too
high. reat 'coke, which is used as an
adsorbent, co~ts about $100 per
-------
Control Methods for thc Removal of Sulfur Oxides from Stack Gases
2.
metric ton and 0.2 Ih. must be re-
placed for every pound of 502 gas
obtained. Heinluft is trying a new
lignite coke which costs less ($25
per metric ton), has low attrition,
and maintains a 502 removal rate of
70 to 85% (1).
SULFACID: Another process which uses
char for an adsorbent 1S the Sulfacid
process developed by Lurgi Gesellschaft
fUr Chemie und lIuttenwesen mbll. in
Germany. A plant for treating I.R
mi 1 lion cubi c fect per hour of waste
gas from a sulfuric acid plant is
presently heing huilt (1).
In the process, as illustrated in Figure
4, the dust free flue ~as with 502
---- ------- ----.- --- -- ----------
-- -- -- ----
Flue Gas from
Dust Collector
Gas Cooler
Sulfuric Acid
l
2.
The acid concentration is low,
3.
Acid resistant materials of con-
struction are required.
HITACHI: A proccss similar to the
Sulfacid process was developed ~y
Hitachi, Ltd., of Tokyo, Japan and is
presently bei~g operated on a 50 mw.
unit in Japan (I).
3.
The process uses six gas-contacting tow~r~
in a cyclic manner. A single tower goes
through a 30-hour cycle of adsorption with
uncooled gas, 10 hours of washing with no
gas, and 20 hours of drying. The stack
gas first passes through a wet tower and
then a dry one whi ch removes the acid
mist. A weak sulfuric acid of 10 to 15%
Gas to Stack
Wa te r
Adsorption Tower
-- -- ----
- --- ----
5ulfacid (Lurgi)3
-----.---
-- ------
l'igu!"~ 4.
l'UIH:~fltr:ltioIlS from n.s te> 1.500 ::; pent in
lJrgl' dmoullt", the maxllntlln COlll'entrat ion
i" .zS to :II)':" 1'11(' final l'oncentration
depends Oil till' i !llet gas temperat ure (I).
The proces~ ha,> the advantage of bcing
~;imrle. The disadvantages, however,
i nc1uuc (t1):
1.
l~e flue ~as i:; cooled to between
140 and 16()O!, , thus limiting stack
K"S hnoyancy.
concentratl on is prouuced, wh i Ie rC'mov i ng
90% of the sulfur oxides (II).
The prol'l':;s has the advantage of a tempera-
ture drop of only S:;o,;. The cost of the
elaborate damper system I'l' +
CaCO:,> . MgO + CaO + 2C02"
:;
-------
Control Methods for the Removal of Sulfur Oxides from Stack Gases
MgO . CaO + 2S03 = MgS04 + caS04' and
MgO + CaO . 2S0/ 02 " MgS04 + Ca504'
For this process the limestone should be
ground as finely as is economically pos-
sible.
Preliminary work indicates that an econo-
mic optimum particle size may be as low
as 10 microns. These particles need to be
uniformly distributed in the 2200 to
23000F temperature zone. The gas
temperature in the reaction zone is
between 1200 and 2300oF. The temperature
should be.high enough to calcine the
limestone particles but not so high as
to cause them to "glass over" or sinter.
The concentration of S02 in the boiler-
reactor is about 0.3%, and the contact
time here is from one to two seconds.
This short contact time in the temperature
zone is believed to have an adverse
effect on the process efficiency.
During this time the limestone must be
calcined, the S02 oxidized to SO~, the
S03 reacted with calcine, and thIS
diffused at least part of the way into
the solid to permit further reaction.
Sulfates, unreacted lime, and fly ash
Iron oxide, which is present in most
dolomites, acts as a catalyst by speeding
the reaction of CaO and S02 to CaS04 and
by catalyzing the reaction of MgO and
S02 to MgS04 (12). Dolomite or limestone
injection can take two forms: dry
removal of SO, by injection of the
additive into.the gas stream, or wet
removal following the injection by
wet scrubbing (6).
I.
TVA DRY LIMESTONE INJECTION: TVA has
heen :nvestigating a dry process and has
started an IS-month tune up campaign on
the process at its Shawnee Station in
Paducah, Kentucky. The goal of this study
will be to improve the removal of sulfur
oxides from the presently attainable 20-
35~ to at least 50% (13). The flow diagram
for this process is illustrated in Figure
r
.J.
- -- -- ---~-------~_._-- --
Steam Superheaters
and Reheaters
Economizer
--
----
Stack
- - - - - --
High
Efficiency
Precipitator
l
l
Air
"-
"
"'
~
Figure 5,
TVA Dry Injection process5
(,
/
/
/
+J
~
o
Q..
c:
o
:;;
U
QI
'r")
c:
.....
QI
c:
o
....
cc
i;
I
......
IU
o
W
-------
control Methods for the Removal of Sulfur Oxides from Stack Gases
are then removed by a mechanical dust
collector and an electrostatic pre-
cipitator. The remaining gases are emit-
ted via the stack (14).
Investment costs range from $3.95 per
kw. for a 1000 mw. unit to $7.75 per
kw. for a 200 mw. unit in existing plants.
Depending on the plant size. operating
costs are expected to vary from $1.03
to $1.39 per ton of coal burned (for
$2.05 per ton of limestone cost, 3.5\
sulfur in the coal, and 200\ stoichio-
metric limestone addition) (14).
Some of the advantages of the dry process
include (14):
1.
Simplicity of process.
2.
Fase of operatIon,
3.
rapa~illty of responding to varying
load requirements.
4.
Sm..ll capllal investment and ease
of Installation for existing plants.
5.
Small direct effect on combustion
eHic iency.
6.
Reduction of boiler fireside tube
corrosion.
7.
Control of sulfur oxides without
production of a saleable by-product.
Some uf the dl~advanta~es are:
1.
!'our sulfur oxide removal even with
eX(eS5 limestone
2.
NecessIty tu upgrade particle
collector for installat ion in
existin.: plants.
.~ ,
Redllctl011 in boi ler l'fficiency and
incr('.!sc In operatIng and mainten-
ance costs due to increased slagging
and hiKher dust loading.
4.
SensItivity of operatinjl and capital
costs to plant capacity.
s.
I nc 1','..1 Sl' I n the :Imount of 50 li d
waste for disposal.
Although much work has been done by
TVA, NAPCA, rsso, and many others on
the development of this system. much
more work IS necessary to solve certain
engineerinK problems which would hinder
if not prevent the use of such a process
commercially.
Other dry injection processes have been
proposed. Descriptions of these technique~
will follow.
2.
BABCOCK AND WILCOX ESSO: A new dry
injection flue gas desulfurization pro-
cess has been recently announced by .
Babcock and Wilcox and Esso Research and
Engineering. Sixteen utility companies
will support a $7 million development
program. Pilot plant studies will be
conducted at a plant of Indiana Michigan
and Electric. The ultimate goal will be
a commercial system capable of removing
99\ of the particulates and 90% of the
sulfur oxides from power plant flue gas
by 1973 (15).
In the process, as illustrated in Figure
6, S02 is absorbed by a unique dry mat-
erial which is easily regenerated to
recover marketable sulfuric acid. This
process offers no stack gas buoyancy
problems and eliminates the waste disposal
problems that have beset other injection
processes. No cost data are currently
available (15).
3.
DRY NAHCOLITE INJECTION: Nahcolite is a
naturally occurring form of sodium bI-
carbonate. Precipitair Pollution (ontrol,
Inc. has investigated and developed an
502 removal process using Nahcolite in-
jection. The mineral is injecteJ into
the flue gas stream at 30no~ to 3SnoF
forming sodium sulfate which is then J'l'-
moved along with the fly ash. "i lot planl
studies at Southern California Ldisnn'~
Alimitos plant have indicated 70"0 S()2
removal and 100% SO] removal. "lIrttll'r
test ing is planned at a lI.S. (;ypsllm 1'1.1111
in Clark, N.J. Although the !ow-tcmpl'r;o-
ture reactivity is an asset cnabling ill
jection outside the 110i ler, the main
problem for industrial application wi 11
be the availability of Nahcolite at a
at a reasonable price (l6).
4,
MOLTEN I~ON: Blad, Sivalls, and Bryson,
8 subsidiary of International Systems and
Controls, has announced a new 502 removal
process, as illustrated in Figure 7.
Pulverized coal, limestone, and air afl'
injected into the molten iron where the
coal is partially burned to carbon mon-
oxide. Elemental sulfur is released,
binds with the iron. and floats to th~
surface forming a slag with limestone.
Elemental sulfur can be recovered from
-------
Cont TO 1 Methods for the Removal of Su 1 fur Oxidcs from Stad Gases
H2S04
Electrostatic
Precipitator
Sulfur
Recovery
Air
to Stack
Boiler
Fixed Bed
Sorbent
Reactor
Ash
Regeneration
Gas Producer
Fi).:ure t>.
Babcock uno Wilcox-Esso processlS
,. -- ..---------..
---
Combustor
offgas
\1\ \1 \
Slag
Limestone-air
/lance
Slag-iron
separator Slag to
desulfurizer
I ron to
granulator
Mo 1 ten 1 ron
Metal
shell
,
Refractory
l
Figure 7.
Molten Iron processl7
-. .-.--------
'-----'--- -- --'-------.-------.-
-------
Control Methods for the Removal of Sulfur Oxides from Stack COSf>S
the slag. Combustion off gases are then
completely oxidized with secondary air
and proceed to a steam boiler (17). No
efficiency or cost data are presently
availabh"
costs are considered, a net operating
cost of $0.36 per ton of coal is realized
(5) .
Many of the advantages and disadvantages
of the wet process are the same as have
been mentioned for the dry process. Some
additional advantages include (19):
5.
FLUIDIZED ~EII: The Offi(;(' of C081 Research
and NAPCA are sponsoring research on
fluidized bed. coal-fired hoilers. Utili-
zation of thi~ combusti0n technique with
=he addition of crushed limestone into
the fluid bed has been proposed as another
route to controlling sulfur oxide emis-
sions, Befor~ fluidized bed combustion
can becomt commercial, much basic re-
search is needed in the areas of additive
size, gas velocity, operating temperature,
and waste recycle and disposal (18).
4.
Indications of a 20% - 30% removal
of nitrogen oxides.
1.
High 502-S03 removal.
2.
Elimination of an electrostatic
precipi tator.
3.
Reduction of stack costs.
6.
COMBUSTION ENGINEERING WET PROCESS: The
wet process combines the afore mentioned
dry injection process with wet scrubhing.
Combustion Engineering in coop<'I'atioll with
Detroit Edison Company has developed
this process, which i~ Illu.trated in
Figure 8, There arc two commercial instal-
lations usin~ this process at present
and a third is slated to he operational
by 197 I (II).
CHEMICa-BASIC: The Chemico-Basic Corpor-
ation process uses a central recovery
plant approach, in which the central pro-
cessing plant recovers sulfur from the
spent absorbent of several power plant
boilers or other 502 emitting industrial
plants. The process is slated for full
commercial testing on a 150 mw. oil burn-
ing station of Boston Fdison. A reduction
of S02 emissions of 90% is expected. The
spent absorbent is to be shipped to an
Essex Chemical Corp. plant to recover up
to 17 tons per day of sulfur as ~ulfuric
acid (21).
Some disadvantages are:
1.
Increased solids for waste disposal.
2.
Necessity to reheat stack gas to
maintain buoyancy.
7.
In thi~ pl'ol'l'~' the pulvf'rilt'd additive
is injected into tht' furnace where 20 to
30~ of the sulfur oxides is removed.
The remaining SO;: and calcined additives
then pass through ,I prehe
-------
COlltrol Methods for the Removal of Sulfur Oxides from Stack Gases
- - ---- --- ------
TO STACK
2S0°r-
FURNACE
r----,
I :
I I
I lOAL I
I SUPPLY I
I :
I I
L-- _....J
GAS
STACK
REHEATER
600°F ArR
nr:MrSTER
I.IMESTONE
SUPPI.Y
---
SCRUB8ER
, RECYCLE
AND
MAKE-UP
WATER
MIl.!,
SETTLING
TANK
TO DISPOSAL
I'igurc 8.
Combustion Engineering Wet processS
-- --------- .- --. - --
I.
j\\JIU.'\1I OF ~lINI.S, III{' Blln'au of Mines IIIIJer
(III' "IH'I1~"r~lIip l)f the rJ.s. Public lil'illth
'~e'rV1L't' 1I.ls ~C'!L'L'tl'd ,llId Joveloped a <:<111-
J"l.ltl' for laq:c-scalc sulfllr oxiJe re-
mu\'al. i\lthouRh developers claim 90~.
1'L'\'IIVI'IY of thC' SO;? from tl1l' gas 'itrcam
11\). IIIJici\tions arc that furthC'r work on
thl' prol'('s, is h('ing halted.
N.I;?()
nle flow diagram is illustrated in Figllre
9. Flue gas from the huiler i!o\ cleaned
and passed at a temperature of about
62501' to the reactor where it flows
countercurrent to a stream of semispheri ..a I
alkalized alumina pellets having a size
range of 10 to 14 mesh (23). This
material, essentially NaZAl204 or
!o\odium aluminate, reacts with S02 and
oxygen to form a stable sulfate (10).
From the reactor the spent absorbent
passes into a regenerator where it is
contacted by a reducing gas at about
12000F. The alkalized alumina is re-
generated and hydrogen sulfide is formed.
The regenerated absorbent is recycled
back to the reactor and the hydrogen
sulfide is converted to ele~ental
sulfur by the Claus reaction (the burning
of one-third of the H2S to 502 followed
by the reaction of the two to produce
elemental sulfur) (4). There is some
attrition of the alkalited alumina. Thi5
plus its relatively high cost ($0.25
Ihe' ah'iurhent mcdium is a co-precipitate
of ~odillm and aluminum oxides (with so.l-
illin o;nut' ma\..ing up ;?O~, of the total) (4).
The ahsod)cnt is regenerated by contact i ng
i t \~ i t h ;a redue i ng gas sueh as n3tural
ga~. hyJrogen, or producer gas. The fo1-
Il\\,illg reactions arC' bc1iE'vt'd to occ\lr
( .::q :
N;a~U . so;? . ~ 02 .. N82S04
Na2S04 + 4112 .. :\H20 + 1125 + Na20
NII.:-S04 + 4CO + 1120 . 4C02 + 1125 +
11)
-------
Cuntrol Methods for the Removal of Sulfur Oxides from Stad. Gases
SORBENT
MAKE-UP
~
~~
~CI.
W
tI)
PURIPIF.D FLUE GAS
TO AIR PREHEATER
AND STACK
SORBENT
STORAGE
IIOPPER
GAS TO SULFUR
fLUE GAS
D-
o
f-f-
VJ U
::JW
0....1
.->
o
u
IX
o
t
<
W
IX
IX
o
~,
w
z
w
~
~
RECOVERY PLANT
I; LlJE GAS
REDUCING GAS
FROM BOILER
DUST
RF.t-()VAL
figure 9.
Bureau of Mines5
---- .-.---------
per pound) necessitates a fines collector
and an absorhent makf'-llp stream.
Some of the disadvantages are:
1.
The process is difficult to apply
to existing plants.
(~sts fur this process arc difficult to
estimate. For an 1100 mw plant the
estimated capItal investment is $10.64
per kw. .tnd the uperating cost is $1.54
per ton of cn:ll. 'The operating I.:ost is
in the nmgp of $0.75 to $1.00 per ton
if the by-product 15 cnn~ldered (6).
2.
High temperature and large tonnages
make circulation of the absorbent
difficult .
3.
I.oss of the absorbent by side react-
ions and attrition increases operat-
ing costs.
SOJOl' uf rho.' ..
-------
Control Methods for the Removal of Sulfur Oxides from Stack Gases
3.
SRI; Variations on the alkalized alumina
process are being studied. A process
financed by Slick Industrial Corp. and
developed by the Southwest Research
Institute substitutes sodium aluminate
for alkalized alumina (5). According
to SRI the sodium aluminate absorbs
0.34 grams of 502 per gram of absorbent
or 85\ of the S02 for the stoichiometric
amount of aluminate. This compares to
0.25 grams of 502 or 65\ of the 502 for
the stoichiometric amount of alkalized
alumina Fly ash present in quantities
equal to that of the absorbent does not
hinder the absorption efficiency. SRI
states that it should be possible to
recover the sulfur directly in the
absorbent regeneration step (fS).
The sodium aluminate process has several
obvious advantages over the Bureau of
Mines process (26):
1.
Higher efficiency permitting the use
of smaller capacity equipment.
2.
Insensitivity to fly ash permitting
,I lower efficiency particle collector.
~,
Llimlnation ut th(' Claus unit for
recovery of the sulfur.
More work must be Jone in the form of
pilot and prototype testing before sound
cost d~ta are available,
I.
OtlH'J' Processes lJsi ng Metal Oxides
1,
p,\r-~II1: 1'1'0\1a['l)' the most advanced ab-
sorl>ent process is th(' [)AP-Mn process
d('v<'lopcd by Mitsuhishi lIeavy Industries,
ltd.. Tokyo. A unit for.1 50 mw. oil
I>lIrllll1/< rlant ha" operated successfully
fill' almost 'I ye:.r (I). More than 90\
J'\'OIl1Va I (If thl' sill fur content is claimed
fot'd ,111, SO.: ;,tn'am. The proce~!i, as
i IIII~I ratt.J In Fi\ture 10, i:l dcsigned to
I'l'00nve suI fill' ox ides from fluc ga~ usinlt
,1/1 ;1.' t Iv a tt'd manKRnese ox i de> ab~orbent and
tll J'('l'over an ammonium sulfatl:' by-product
thl'ollj:h fl'g(,l1crat ing the :Ipent libsorbent.
The following reactions are involved (27):
MIlOx.YII,Y .. S02 .. 02 " MnS04 .. YI120
~1nOx'YH20 + 503 + 02" MnS04" YH20
I ~
MnS04
2NH40H ~ Mn(OH)2 + (NH4)2S04
+
Mn(OH)2 + 02 + H20. MnOx.YH20
The powdery manganese oxide is fed into the
fluidized bed type absorber where it is
dispersed in the flue gas stream and reacts
with the sulfur oxides. The excess manganese
sulfate and unreacted absorbent are sent
to a cyclone where 90% of the solids are
collected and sent to the mixer. The re-
cy~led solids and the regenerated manganese
oXIde from the crystallizer are mixed in a
"ratio of 6 or 7 to 1 depending on con-
centration of sulfur oxides in the flue
gas. This stream is now mixed with a flue
gas slip stream through the disintegrator
and accelerated by mixing with the main
flue gas stream at the bottom of the
absorber. Absorption occurs between 210
and 3600F (27).
The fines portion of the recycled solids
stream is collected by an electrostatic
precipitator and dissolved to form a 70%
water slurry. The slurry and an ammonium
hydroxide solution are fed into the
oxidizer where injected air regenerates the
absorbent forming manganese oxide and
ammonium sulfate. Any soot in the stream
is removed by kerosene flotation. This
would be unnecessary if the flue gas were
precleaned (as would be the case for a
coal-fired power plant). The solution
is filtered, the ammonium sulfate solution
is sent to a crystallizer, and the wet
cake of absorbent is sent to the mixer (27).
Estimated capital costs for the operation
of an oil-burning 500 mw. plant are $13 per
k~. (28). For an oil-burning 1000 mw. plant
wIth $32 per ton credit for ammonium
sulfate, the net operating cost is $0.55
per ton of fuel oil (4).
Thl' DAP-Mn proc:ess hus many advantages (28):
I.
Low pressure drop.
2.
Low power costs.
3.
Low maintenance costs.
4.
Low absorbent regeneration costs.
5.
Small gas cooling (20-60op).
6.
Carbon steel construction in most of
the equipment.
Two drawbacks would be possible problems
in scale-up and the precleaning expense
-------
Absorber
Co 11 ectors
Fl ue gas
Water
r-'" ~I -1
I I
I- I
Mixer L__-
from
Fil ter
Di s integrator
.....
~
Vent
t
I
I
~
:I
r+
..,
o
-
J::
It
r+
:r
&.
...
Oxidizer
...,
o
..,
Fi 1 ter
r+
:r
"
'"
o
B
o
<
II>
.....
to
Crystallizer
I
Soot separator L -- t?
M1 xer
L----E;Air
Aqueous Compressor
allll10nia
o
...,
~
c
.....
...,
c
..,
a
)(
...
~
o
'"
:>
c
B
Figure 10.
Mitsubishi (Dap-Mn)26
V;
...
III
"
r
E:'
'r.
"/.
-------
(olltnl! ~Iethods for the Removal of Suf1ur Oxides frOll Stack Gases
for coal-burninR power plants.
,
(;JUI.I.U: A.I;, fUr Zinkindustrie vorm.
~I Ih~lm ~rillo has developed a process
for rcmovinR sulfur oxides which uses a
mixtllre of mrtal oxidc5 as ..n ahsorhent.
,\ t('q uni t h.15 operated successfully for
.Ihout ~I months (I), This unit hils Tl~dIlCCo.l
!I()':, of thl' sulfur oxide emissions from
.. 'H 11 f II r I" an J p I an t (11).
III<' ..h',orhl'nl, II slurry of mlingilncSl' and
n\:lt-:IIt'~"lIIn oXIdes, is dl'posited on a
,'arrit'r sIKh a!' c('''e,and contal'teo.l with
flue ~as frum a Just ~allcctor in two
series rcactors, the first at a temperature
hNWCt'n .!SO and ~OO°F and th(~ !il'cond
Iwlwl'l'n 100 IInd 175°r:, The absorhent is
then rCKencratcd ~y heating with co"e at
1,170 to 1!)/10o" (h). This reduces all the
sulfur compounds to S. illS, or CDS which
an' slIh~r411('ntly burned to Rive a rich
q r('am of SO" The calcined absorbent IS
no\; slurTlcJ'\..lth Wi,lt!'t, make-up absotbent
IS ,Iuued, and t hI.' slurry is ready for re-
IIs(' (,'I),
,'osls have hren estlmatcd at bl.'twcen $0.75
,lIId $1,:0 I'er t,m of fuel for a 300 mw.
1'1,1111 1('),
:-0""", 01 I Ill' ,Id\'anta~t'" arc (1,(":
,\ 1 1 ,. I I I "11 I', 11<' I
" 1'1'l1h 1 l'lI1,
l U'I'.( I Ill' 1 1\111 l,ll1
I", "f r"l'hol1 Sl t,,'J,
,\I "", 1'1' I 1""
i', 1';01' I J,
"1>"<1l'l't 1<111 :llId n'~:"nl~I'"t ion qt'l':-; rn..y
ta~(' pial'!' 111 diflt'n'nt lo('atlon~. This
1nt';II1S" reJIHtion III tht' Sp,ll'l' rcqulr-
I'd r<1r puw,'l' plal1t Illstallation,
",,' d I s,ldvallt.l~l'~ ,1ft' (4):
J,
I he 11111 r";III'" t Iuc 1:01:-; mllst be cooled
I>"f,'I'l' t 1'I',IIIIII'nt,
lilt' I'I'I'SSIlI'" drill' throllKh the ,'Okl'
hl'd I" ,II'P 1'1', i:lh I ('
1'.\\I"'r ,'1;011' 1lI,'I;ollatlol1 wOlild rC4uire
,I hq:h "fflrIClh'\' p;'rti,'I.. t'ldlcctor.
"
I I H~tA "AI!! ",111.1 Th., 'it I II pr<1l't""
",1111: 1'1:" 11 t' ash a<; .111 uhsorht'l1l 1:-;
II
said to attain up to 95\ SO? removal
(1). This process is atta~nlng 80\
sulfur oxides removal on a 10 mw.
power plant. although it is reported
that this pilot plant IS not currently
operating (II).
Tho lignite ash. which contains ,10-50\
liml.'. h hydrated to form l'alclum hydro-
xide: ftlue gas from tht' power plant
du~t collector is contacted with the
absorbent at ahoul ~rnl~f in three s~rieb
reactors. TIll' tl'slIlting caldum sulfite
can be heatt'tl to 1 i h.'rate S02 for sul-
furic 4c1d production.
The desulfurizetl mass is recycled with
Ii recycle-tn-feed ratio of 2 or 3 to 1
(61.
Although no cost data have been released,
investment costs arc ~lIid to be lower
than for the Reinluft process (1).
The advantages for the Still process
are (4):
1.
2.
3.
Low absorbent cost.
Elimination of corrosion.
Limited cooling of the flue gas,
The only drawbac" of the process is
that suitahle lignite ash is not ava11-
ablt' .
f,
Chemical Scruhhinl(
,1.
B,\'"fI'RSb\: Chemical s<:rllhhinR for re-
nlOVU 1 of S02 WIIS first pllt i lito fu II
scale use in 19:\.1 at the Rattl'rSl'a power
station in London, Lnl(lanti. In this pro-
t:ess, liS illu!'tratctl in 1;lgurl' II, I:halk
is added to normally alkaline Thames River
water. The flue 1/"<; is passeJ throul(h two
wat~r.scrubhing towers in seri~~. ~here
calcium sulfite and cah:ium sill fate ar~
formed. An aeration tank is provided to
oxidize any calcium sulfite to the sulfate.
The total I.'ffluent is then returned to
the rivcr'. The procl'ss has been ahle to
remove 90 to 95':. of the ~02 from flue
gas. The now ob~oletc <;y~t~m had an
ol'eratinK t:ost of SI,~5 to $1,40 per ton
of coal hurned (10),
Soml' IIIIIJor d h;;idvantlll:es of I ht' system un':
I.
The fluu liDS exits at a temperllturl'
neur 1l5°t: and hl'lIce has almo!\t no
huoyuncy.
A I r po llut Ion is cllrhell lit t hl' expl'ns~
of w,tcr pollution.
2.
-------
Control Methods for the Removal of Sulfur Oxides from Stack Gases
-----~---------- --- --- -----
AIR
FUll' CIIS
350°F
IIII{
HLAlll{
110 I LI:i{
I'lmNIICI:
mAl. A~!I
H gure ll.
- n - -..-. - '. - - -- ---- ----
- - - ---- ------
2,
SHOWA OFNKO: A scunhing procc~s using
an ammoniacal solution has been tried
on a large scale by th0 Showa Uenko
Co" Tokyo. .Japan (1). I n the process J
a~ illustrated in Figure 12, the flue
---- --- -----------------.-------------.-------_u_- ---
I\M/otON I A
-IT
l.l\:; I'I(()M
AII{ III!ATI:H
';('HIJIIIII',I(
- WI\TI.H
I
I
- _I_-
I
I
L-
!
i
I
l__~--- -
Figl,re l~,
-~ ---_._-~ _.---_.__..._-~-_..
--- --.----".- -~--.- -- - --------
,~as stream from the ai.r prehcatcT is
injected wit.h ammonia as early as
possihle to react with any SO,~. thus
prevE'nting corrosion. Tbe water is
then injected to cool the stream
hf.'fore I('rubhing. Aft('r this stream
is SCTlIhh(,d wi th mOTe water, 1111'
1
TO STACK
RIVER WATER
~
I
I
120°F I
12Sopl
I
I
I
_I
- ----
SCRUBI.!!Nt.
TOWER
SCRUBBING
TOWI~R
TO RIVER
'1~~~n~J
lIattersca8
--- ------
resulting Iiquot containing both
ammonium sulfite and bisulfite is
treated with ammonia for complete
reduction to the sulfite. Air is in-
jected by a special ~ethQd to convert
---- ---- - ---.
TO STACK
...
AMt-KJNIA
~ I
I
I
I
-'
r
~;lJl((a:
ll\NK
1\ II{
, 4
ShOl~a Denko
I\MMONI IJM
SIII.liI\T/:
SOLUTION TO
CRYSTALL I ZI;R
the sulfite to a recoverable ammonium
suI fate (4).
The company operated a 2S mw. test
uni t on an oi 1- fj red process uni t
hut has now stopped operation hecause
the prices for ammoniLUII sulfate were
IS
-------
I:rnltrol Methods for the R~mov~1 of Sulfur Oxides from Stack Gases
I.
Fast reaction rate.
4. WADE SCRUBBER: Another wet scrubbing
SO removal technique has been de-
veioped by the Wade Co., a Division of
Ovitron Corp. A 3000 cfm. coal-fired
test unit at the Gilbert station of New
Jersey Power and Light Co. has de-
::',' ilonstrated 98% removal of theS02 and
fly ash (30).
too low to warrant operation on a
conunerci a I has i s (1).
'Ihe process h~s the following
advantages (4)
2.
Simple process design.
The overall process is very-similar to
the Mitsubishi Ammonia process mentioned
above. The scrubber design, however,
is unique: the. lower portion consists of
a packed cooling tower and the upper
zone consists of the separator. In the
separator the gases are accelerated
and decelerated with venturi-type ele-
ments. This change in velocity allows
the particles to agglomerate, fallout,
and then be rinsed back to cooling tower
by the ammoniacal scrubbing water. A
flow diagram is seen in Figure 13 (30).
:).
Negligible absorhent loss.
Ill' di s..ldvantages arc:
I.
The gases are cooled to about
11So~. thus losing their huoyancy.
('orrosion res i stant equipment is
requ ired.
.' .
!\MMONIA AND Nl:W J.IML: Mitsl1bi~hi, in
addition to the I\AP-Mn process, has
deve loped two Wt't ahsorpt ion processes
which are variations on older ammonia
injection and lime injection processes
(11). Although sulfur removal
efficiencies are claimed at 90% for
both processes, development work has
been reported to have been discontinued
(29) .
5.
WELLMAN-LORD: A wet absorption mcthoJ
using a potassium or sodium sulfite
scrubbing solution has been developed
by Wellman-Lord, Inc., a subsidiary of
Bechtel Corp. A pilot plant unit has
been operated at the Gannon Station of
Tampa Electric Co. A demonstration
- -- ~- -
-..----.- -- ------ ----
LindC Separator
disks
H 2S0 4
COOLING
TOW[[{
to Stack
,STRIPPING &
OX !DATION
TOWER
Hot fl ue
qases
to (NH")2 SO~
recovery
Air
Alilmoniil
Water
Ammonia
Flyash
Settled
fly ash
Figure 13.
Wade Scrubbing rrocess30
II>
-------
Control Methods for the Removal of Sulfur Oxides from Stack Ga::.C's
unit at the Crane Station of Baltimore
Gas and Electric was operated until
September 1969. The process has been
licensed to two Japanese fi rms for
Asian sales and promotion. The first
full-scale commercial application will
ot' for thl' Olin Corp. at a 700-ton-per-
day sulfuric add plant scheduled for
completion in late 1970 (31).
The original design called for a
potassium sulfIte scruhhing solution.
11\(' ahsorhcd SOZ formed potassium
hisulfite which on cooling precipitated
nut <10; potao;sium pyrosulfite. Steam
stripping the pyrosulfite produced
anhydrous S02 for recovery and re-
generated potassium sulfite for recycle.
Pilot plant work at the Gannon and Crane
stations indicated high energy require-
ments for the potassium solution system.
Parallel work was done on a sodium
solution system to reduce utility re-
quirements and capi tal costo;. This
sodit~ system will he used in Wel1man-
Lvrd's first commercial installation
for OJin. Detai led technical information
for the process hao; not been released
and only the most general type of flow
diagram is available (see Figure 14),
131 )
WelJman-l.ord hao; predicted pC'rformance
figures for their proceso; using the
"IJIJllIM SY)TlM
to Stack
Flue
go';
sodium system. Better than 90% SO,
removal, 97% 503 removal, and 90% fly
ash removal (with a loading of 0.5 grains
per cubic foot) are claimed (31).
The capital cost of the unit for a 500
row. coal-fired power plant using 3""
sulfur coal and recovering gaseous S02
is estimated at $1.8 mi Iii on or ahout
$15.5 per kw. This figure drops to
$13.9 per kw. for a 1000 row. plant (31).
6.
MOl.TEN CAHBONi\TI': A proces~ for
scrubbing hot flue gases with a mixture
of molten salts has been developed hy
Atomics International, A Division of
North American Rockwell Corp.
In this process, the flue gas passes first
through a high temperature electrostatic
precipitator and is then contacted in
an absorber with an eutectic mixture of
lithium, sodium, and potassium carbonate
at about BOooF. The resulting solution
of carbonates, sulfates, and sulfites
passes on to the reducer. At 1l000F
in the reducer the sulfates and sulfites
in the solution react with producer gas
(CO and H2) to form a sui fide solution
which is sent to the regenerator. In
the regenerator at BOOOF the sulfide
solution is reacted with C02 and water
-~ ---. -.--.--- -.-.---.------ -- -~-_.
Sulfuric
acid plant
Water
Liquefaction
plant
Sulfur
reduction plant
r Iy ,!<,h.
')°3
-- I\b<,orht'r art'n - -- -- - - - - - - - - Chemical area
-----
1'1/:111'" I t\ ,
'\ )
We] Illiall-l.ol'
-------
,'''lItrol ~I"tl\l\d"-, fpr the 1{l'lIIoval pf Sulfur Oxiucs from Stack Gas('s
(11'<)111 th,' I','dm','r) yil'ldlllg a regcllerated
IIllJJtl'l\ l',lrhlJl\ate IIIlxtUrL' t,) the absorber
,llld .I II ,S ~t ft'.J1II tp ;1 CI.IUS ul1it. A flow
dl;lgralll- I~ ",'el\ 111 I;igul'l' lS, (32).
1111'1' 1'1.111': 111(,11~()SI\111
LASES - 1'1:1 ( 11'11 \ [(H{
,'{IIII . "I
,\lthpugh ol\ly hl'l1('h ',<"ill'
l'oml'll'\("1. 1)'1':. rt'l1iova I (}f
"-, t J't' ;IIII~; l" 111 t ; 1,1 11 i 1\ i: (1,:~ to
rl'jH>rtl'd, Thl'rt' art' alslJ
the 1II,lItt'1\ salt tl'd\lliql\c
1\ it 1',,,;,'1\ ox i d,'o.; (~2),
- ... - ---- --
I (J ,'-,1 \('1\
.Y.
.. l--
.~ '
,.,
.? :0
:"1 ~
t .\I{iI() " ,1\'11 ~)
',111.1,\ 1 I S
~IJI.I 1'1'1.:-.
The disadvantages are:
1.
Thc ~ystem is corl"Osive,
---- ---" --_.
. -~.._.. -- -.
.- -------
- ,-- - - ----I
I
1:It:OV'IHIIJ II,S
COZ,WATEl{
I{I (:I.r\I.H'\TOI{
/;00°1'
MOLTEN
CAR 110 RATI': S
& SULFIDES
I{ I'HIIl'I R
1100° I'
_!'I{(I.IUICI.I,
,;.,:-;, ('d,11 >
I'I.Y ,\SII
'10 1~'SlI;
I'i \'.lIr<, 15,
Molt!'n Carbol\ate !'ro\'cs0.;3J
\'Ol'k 'h ;&'; ht'el1
Sf)2 il\ gas
~':, Sf), h.l'" ht'cl1
iI1Ji<'~tipu~ that
('al1 ,'outrul
"'Ollll\,"-' IntcrllatioT\,,1 l'~tilllatl'~; that H
SII! fllr I'ri <'t' of $'IH 1't'1' ton would l'om-
I'lt-It'ly off~t't tht' 0l'el'alll1~~ I ()~t. and .1
o.;ulfur I,rin' ()f $2,~;\ tOI\ \.'Hl!d lIIake it.
('('ol"'l1lically "(IIIIPt't ilil/e with tht'
.!'>!(llIIil" I"'uc,'"-,s, 'l'h., .."-,11111,,1"0 capital
,'u',t i~ $IO,2S I'l'l' ~w, with all operating
l'Oq ()f $I,~f) pt'r ton heforl' ('rt'dits
for f'L"'OV\'I"l'U ~lIlflir arc ('()lIsiu"I'cu (25).
The pru,'C'ss has thc 1'111 lowing
;Idvautages (h):
I,
The I iquio I'equi n'ment is
~mal ler th;1II for ;:tqueous ~y~tems,
A hot. (Indi IlItl'd gas stream is
.'mitted,
\,
Nitro~en oxides may hc removed,
I H
I.,
The' r('gt~neratioll is difficlilt
hecallse t ht' rat e of n'act i on of
sulfitc and sulfate 10 slilfid!'
is slow unt.i I a temperaturl' of
ahoHt I L500l' is rcadwd.
7.
The process is hard to apply to
existing rlant~ hc\'allse ac\'(o<,~
to un 800°F ~as ~,tream is COIII-
p1 icatt'd,
I'OTASSIUM !lOUMATJ:: l.ah(>I'al (lI'Y ;llId
lJl'nch scale stlltlies have h!'t'll Ut'
VI.' loped for relllov i ng 1\('1 t e r th:1II
RS't. of th(~ 5111 fur oxides from fille
Rlis hy scruhhing with a cllncontrateu
solution of potassium formate (KOOOI) ,
'nlc S02 and the formate react at
2000F to form potassium thiosulfate.
The thiosulfate i~; then reacted with
additional formate at 540°F to
produce potassium hydrosulfidc.
The hydrosulfidc is strippeu with
carbon dioxiue and steam, releasing
112S to a Claus unit. The remaining
potassium carhg"at.e and hicarhonate is
reullt'cd at 540 F anu \000 I'SI wi th
~,
-------
Control Methods for the Removal of Sulfur Oxides frolll Stack Gasl'S
carbon monoxide and :=;team to
l'ratcd potassiwn formate for
hack to the s.ruhher (33),
form regen-
recycle
" prelllllinary economic an:dysis has been
made for a 1500 Ill"', pow<.>r plant at S7~o
Inad f cstilllat~d at $13.~ per
kw,. and th~ opcratinp. l"t1sts arc estjmat-
cd at $2, OR 1'l'1" tOI1 of coal ht:fore sulfur
,'n',lit. 01' $1.43 per ton coal with a
"1111'111' cn'dit or $2S lWI' Jong ton (33).
Thl' PI'O,'(':;" has thl' following advantages
[5,,) :
1.
N\J g.a.... rl'hl'~it
J'l'qui )'l'd ,
i:;
~Ii Id ..Olhll t i,IIIS I'rev;1i I
of 1'l'~~el\('r;lt IlIJl.
rill' a II S 1 ag('s
5.
1'1,,' s~'s t "Ill I S ,II I Il11 ;1)'."111 lilt' IJI"II,'I... :1I"l' l'l'I~"I\-
"l'oIll'" hI' h,':!lln!'., Thl' ';0, 1111I'1':,ts wOllld he $13,80 IH'1" kw, fo!' an 800
1111", plant ;lI1d Ihal :1 sulfuric acid price
of $18 per ton would havC' to bl' reali:l'd
for breakeven operation (34).
3. IONICS;STONE ~i WEBSTER: A demonstration
plant is current ly being devC'loped by
., Stone & Webster Engineering Corp. and
Ionies, Inc, This process will use
caustic soda to scrub S02 from flue gas
and will cOllvert it to sodium hisulfite.
This bisulfite will be fed to a stripping
column where SOZ will be recovered. An
electrolytic technique will bl' employed
to regenerate the caustic soda from the
sodium sulfate in the coll~n hottoms.
Saleahle by-product:=; from this regenern-
t i on ind ud(' d i 1 ute SlI J fud.: ad,l. oxygl'n.
alld hyd rugen Ud,
iI.
St:AWATl:n SCnlllll\ I NC: I'I'D1\";so'r I.. fI,
Brumll'}' of the LJniver~i,l)' uf CalifOl'nia,
Berkeley has demonstrated that Sl'uwutC'!'
is an effect j ve ahsorbe'1t for )"'1110\' i ng
SO:? from flue gases, Efficiencies wen'
reported at YO~ IIsing :=;pray ch." .1 list in!'. ill
tnhu]nr fortu (';u' Tn"ll' ,: so lII:lny rador~,
art' involvl',1. The enginl'er rel(llirc~d to
select a process for a specific installa-
t ion must not only study the actual cOS., '1
l'""strllctiol1 ;11)<1 (\1)C'1"nti 011 , hilt lll'mllst '1";1'
I ~)
-------
"
--:
co
-
.,
lat~e
:--:a;l:ai ~~vestDent, Operating Costs (excl~dl~i ty-product credits)
a:-:; Brea~e':e:1 Prices for B;:-Products for S0" Rer.o\'al Systems for an 8';') m"
POl>er 21ant
:s::
~
....
Cat',i'::il Inves::me'lt i Operati:1g Cost
S per klo.", i (Before By-Produce ':redit)
i per ton of ccal
Process
Breake\'en Price
for By-Product
RefereEces
c
c..
'.r
-----------------
3:', 8
10, 34
37, 34
14
5
o
"i
CAT-OX
Kiyoura
CZeinluft
Limes tone
LiILestone
Bureau of
21. 25
11 ,Ie
17.30
Ii'.ject ien-Dr:.'
Inj ect iC'n-\~et
'lines
4.33*
2.22
10.60
1. 75
1. 65
2.45
1.13*
0.36
1. 54
$13.5/T H2S04
$36.5/T (\H4)2S04
$30/T H2S04
....
r:
Battersea
i lIe llman-lord
i ~!ol ten Sal t s
, Chromatographic
$47/T Sulfur
$21/T H2S04
37,34
:c
Q
;;
o
<:
-----------------
15.20*
10.25
13.80
1. 25-1. 40
1. 55*
1. 30
-----------------
-----------------
10
31
25
34
C
."
'"
c
...
,.,.,
c
...
$48/T Sulfur
$18/T H2SO4
* Calculated from referenced cost data by using the "Six tenths approximation".
Table 3--Current Selling Prices for Various Chemicals (38)
o
><
....
0-
~
us
,.,.,
"I
o
a
(J)
...
II>
r.
'"
r
I
!
Chemical
Price
c;')
~
en
~
III
Ammonium Sulfate
$25-$33 per ton (bulk) $39 per ton
(bagged)
$0.11-$0.15 per lb. (cylinders)
, Liquid S02
I Sulfur
~furic Acid (100%)
$39 per long ton
$34.65-$35.80 per ton
-------
COlltrol Methods for the Removal of Sulfur Oxides frolll Stack CaSl'S
dl't('rmi Ill' if a hy-product is wanted, if
the company in qu('stion i5 in a position
to markC't such ~! prolluct, if a market is
:J\ai lahl(' for slid! a product, ::lnd what
('ffl",t th(' ..mount of hv-product produced
\Yl>lild h,1V(, on tll(' local mar"et.
I ;t\..h P"t!l(q,..., !i,ll, '--;\\lnC nbvinu< advantage
,'\"'1" till' I)tlll'I'~; tile C:\T,(IX ,111.1 the char
",I"",'h('1I1 prp,'('s';('s pf"Llducl' a sall':Jhl('
'"lIflll"lL' a'ld; the "iyoul"a "n.l the
~I'I"I"i~"1 l'r"I'('~sC's prllduu. :111 a,'\'('ptahl('
:lIlIIn'>lI,"m ,,,If,ltl' i"1,rtlli/l'l"; th(' dry
11"1'" \PII(' 111.1"11'''" j,.; .11'plicahlr to
"\1',11111'.11<11l> i IIg PI"P""s'. II.IS alii gh
,.,'fi 1 "'II"\, ,111<1 I"w c""t~; ;lIld tl1('
,ilk,d),'!'d ,d'l1n;Il,1 pl"on'~:;es pl'odu,'(' a
1II,1I'I.l"laldl'sldful". J:collomic,.; will determinc
till' ,'lIoicl' or 1'11(' ['rol"l'~': OVl'r .1notll('r,
1'111 it is pl,s,I':lUI" .111,1 I' ,W, :';1',111 I.',
"('\)l1tr\111111~ Ih..ldl'" of Su]fIJr." "11'
I'" 11 lit i oil (',HI! .r~).1 fI',,"'oc i at.I_DII, .J_lHI,:ila 1..
1:-:('\)' ~,S.II'h,:-q
I.
,\ \'. "1.1\1., ""II" l'lIlllItioll: rill' COl1troJ
lIf ~;()) frPIII l'p\oJc(' ,l)t ~ll''''~, P.lrt r II,"
('lIl'I1II,',1I 111~:llll"l'_I'inf~' ~',1 (.:~>I: lHX-19h,
I II)(,I} ,
It~,{1 , ."lInt rl11 l'rllCl'''''''''(''''' CdI' ~~1 ~Il" (1.I~r~
He,Hil ldlJlllH'n'l.ll :.;tattl:-.," 1:I\V.1_!~o.1\~nt'.I~.1:~.1
",' I('IHC ;~lIcI Tl,,'h!lO_I_~;1, 't II) :
<\ 1.1 :)1)",', I IIJiy LlIij('stonc fn,iC'rtioll."
Paper pn,s('ntc-d .J! the () 1st ml'et ing
or the Ameri ,'an 1 nst it Iltl' of Chl'lII i 1.':11
t:nginecrs. Los Angell's, C:ilifornia,
l)('ccmher 5, 1968.
15.
"lit i J i tics to Fund Study of N('w
"0., Pruccss," I:.nvironmental Science
a.!1;! !cch~:lYJ:i:~~nn-)-:- -I-i~-( 19-7())"-
16.
"'iodi um n i C,II"I> Tested
Lllvironml'ntal Sciencl'
,~: 7!)7, (Ii)(~'
rOI' :-'02 Control,"
alld '1~('c!~\.?"1 !~.l'l'.'
17.
"Coal Comhw.tioll ill Molten 11'011 flvoids
S(h I:ormation," ".nvironmenta] Sci,'lIcl'
:.!.J~~ :!:~.c.h~o_I_0ill" 4- (H)-:-0:~-():( I ij-ioT-
ilL
"I'luidi zed IlL'd Comhust ion Should
nelhlc(' fli r Pollution," ~_wl'r, 11,1
(7): 111>, (1"70)
I!J.
fl. I.. PJllmll'y. .1, ,Ionakill. ,I.n. ~I,II'III',
and .J,e;. Sing"I", "1{CIIH'V,11 IIf .'';0,: and
IIlIst from Stack Casl's," ('''II1''U~.ti'lI\, 1(1
(I): Ih-~3. (]9hR).
, I
-------
(tin! rol Ml'thod~ for till' l{crnoval of SuI fur Oxides from Stack Casc~
20.
.J.H. ~1:Htjn, w.e. T..tylor, and A.L.
Plumley," ThC' C-I Air Pollution
Control System," Paper presented at
1~J7() Industrial Coal Conference,
I.C'X i ngton, Kentucky. Apri I 8-<), 1970.
21.
"Stael-. t;as TrcLltmcnt Processes go
Commcrcial," Lnvironmental Science and
li'ch_n.o,I,oj;)'. ,CCR):(;i9;(T970).
) ,
",I"i nt Ventur(' Formed to Market S02
(:un\ n> I I' r<\Cl'SS ," ~:IIV i ron.J!1.t;J1ta) ~J~i9J).£.e
'Inti T~' l'l! no I tI.&Y. ~ (R): 703, (1969).
.!~ .
.1.11. held, ILC. KurtzTlH:k, and U.II.
McCn'.I, "Ilow to Prevent SO" Emis~ion,"
QI~mic,~I, Engineering, 2i (13): 158-160,
11(7)
2,1.
,J , L. Newl' II." ~1ak i ng Sui fur from Flue
(;a~," Chemi~a I ~~nl'erj~ !,.!:.ogrcss.
(~S (R): 62-06, (1%9).
"
...1.
"11,'(\ I'roce~ses Offl'r Economic Rocovery
of Stack t;as SCh," Chemicul and
In~i~lcl'ri ng Ncw~, ~~ (2!)):1~(1968) .
:!h.
"<;()2: Is It a IlcaIth flazard under
No/mLlI Conditions? What Are the
I'ractieal Approaches to Control?",
<':'<):~1 llfle, 7:', (4): 72- 81, (1968).
'7
T IIno, S. Fukui. M. Atsukawa, M.
Iligao.;hi, II. YCimLlda, and K. KLlmei,
"S, ,",'-up of PAP,Mn Sulfur Oxide
('(lilt f'tll Prlq meeting of thc American
In',tllute
-------
IF
~.' E"!II8M T_*, 19"
',1100,000
2,100,000
2,000,000
1,000,000
200,000
9,600.000.
0(:".- . 1101'
TJIIII ., '...11.....
ElecMcll UtlIII,
,....... c:.e...&....
'...11.. ... G. "...
....Ic ... C_'8I
...~..........
u.S. TOTAL
-- ----- d.
. - ----..-.-- -~_.._-
-----
Figure 1. Total NOx emitted In the U.S. from sta.
tion~ry installations in 1968.
NITROGEN OXIDE POllUTION:
\
'bOO
I
'. 300
Q
.
. 175 IINI. fRONT WAll fillED
. 22D IINI. fRONT WAll flll[D
. 32D IINI. TAllCEN!IALlY fillED
.!... 48D IINI. OPPOSED WAll FillED
--"--'-
--..---.-----
SOO
400
200
100
o
o
0.2
Figure 2. Effect of fuel nitrogen on NOx emissions
(data based on West Coast utility company).
Control of NOx Emissions
From St~tionary Sources
111,,1.111
II' 1'11;"';,1"1' \,>1III,lt.
,1111111;11 \ "'1'111'"
About 60% of the total U.S. NOx emissions derive from stationary .ources, 98% of which re-
sult from the combustion of fossil fuels in various applications.
W. Bartok. A. R. Crawford, oIlHI A. Skopp. I ,,so I~f'~carch ;md ~ 1I~IIIp.enlig <:" 1111<11'11, N.J,
I:, .." '"
I \11' II \",1, 1\",1',1 J 1:1'." '11\11'\", "'III-I(
, "(111 :tt 1 ! 1,1 !1., ",1111 "1,,1 .\ II 11,.111111"11 I "'Ilf I ,,1 ,.\,1
IIlilll':'I.II'I,'1 1,,1 11!old. .ill "1,'11 1\1,.11111\ Illdl'IIIII'IIII'
-I "III "I 1111' :" II II I "1'1'11 ,",ltll", ,\ II ! !"dlll! ill"
1 j I 1,1,1. 'j 11 II r 'III ' ,I r "'11 I I \ "III I I' I" ,I .' ,-, j' \ i,-: 111I I:
11\111,,1\1""1 II 1,0111' ,I "'11111111111 ..tld 111 ,kllll1' 1 hI' 1'1'
I'. I I ' 11 ,III' I I II \ . I" 1 ' I III II I "II" 1 I I."" I, I I ,,' ,II' \ I,ll III t II"~' I'
, I t 1IIIIt j II' , ~I I III III I "'1' I "II, '.I I" I '0111 111 d \ 11 :1'-
1,,'1111111,.,1 III" I" II ',II ".11 ;11,,1 ',11 1 4'1111',',1'111
III III -I'll 11"1.11' >0'1111' ,III' 1.1: :'1'1 111.111 111" j' 1111111
'''11'1'
1'1\. L. V.I'. '\ I .',
7()
I'IIII"';..,IIIII~ :1111111111('11 fill' :tlIIIIII lill', ,d' 1111' .,...;11111:114'11
l.d;!! pi Iti HI" 1'.11- cd ':() II:d"III:I!I'd ,1-; \:() I
"ulill.'d 1111111' ".0111111'\ ()f 1111' ,1:1111111:11\ -11111'1'1':-;, 1ht,
,,1"1 Il'il' 1'11\\ .'1' 1'4'111'1':11 111" i 11I111'd 1',\ :tt l'IIIIIIII'd 1"111' :11111111
:',K' ,h,III/\\I'1111\ 11\l111..;111;1111I111.'I'~" :~!I', ",1;1111111;11\
11111' I II :111 '111111 II 1:-\ Ii! III t 'II I' 1111' , II'" ,Ii I I 1 III p" III tI' ~';I'~ II ;111'"
'1\1' ilill 111111 ~';t. pl:III:.." "1' 1110111 d'HI\I'...,IH' ;lIld ('Hili
1111'111:11 t 111111111 111111 --'1111','1 III ;1111\, 1111,111.., 111111
1IIIId'II...11"11 ~HIII'I'j':" :~' ,I'I~'IIII' I, 111.-,11111"', ('I.,;",
111:11 III" :--Ialilln:lt\ \(1 "lItl-. Itdl Itll.ld"11I l'I,..."lt.
LII~q'I,\ 11111I111"'I,,,,"I'II--'II1III.1! \'j"..lIltll'l.. III \:11'11111.
I','illl.'.! ,,'it II 1111' .''''','LII IH'rtnisslol1 ()f
I)rt)~'.n',:s (Vol. hi. No. n FphrlJ.1ry 1971
r'!II'mical F:ngiI\Pt'ring
-------
IIp[ll 1('11 I illll~, /llid I hilt 111111 "lImbll~1 11111 SIIIII'(,f'S sUl'h liS
plllnt~ mllllU(lIl'llIl'illl(' IIlId 11,'1111-( lIill';(, lI('id 111'1' ;m-
p01'11I1I1 IIIII,\" II~ 1111'111 pl'lIi>lems,
111 Ihp f",'sil 1'11,,1 ("Hnbu~tioll sl,,'IIII', ('0111 II lid gas
1,111'111111-( 1'lId) 'I<" 1111111 (III' 111,11111 1/)'. o( l'ombustioll
1'(,IIIII'd Sllltl""III'~' NO, f'llIissions, oil 1'01' IIUlilit Iii'"
IIlId rp(II~" IIlId IIlhf'r milllll' (111'1, (III' thp ballllll'l', Since
"'011111'1 '"11 SIIIII "'S "'PI'(' id"lIllfi..d as I he mn.ior pn)b-
It'OI ;11','a 1'11/' -.:t;IIIIIII;II',\ N(), t'n'I~~IIIII~. 0111' :ts~es!{mf'lIt
"r .,,,,1 1111-( /llid 1"""111 11I111I1I11'"llprl1l1,doJ.n (o(,lI~pd Oil
1'lInlllll'lll1l1 IlIlIdifiral illll l"I'hlllljllt'~ 1111111'11 lit limiting
Ihl' (", mill 11111 III' 11 it rlll-(pIIIIXld.'s, II lid Oil 11111' glls 11'1'111-
'11"111 11'('111111111"s I'a"abh' of 1'''11111\'1111-( th,'s,' oXides,
1111('1' tOI'mt'd
NO formation
(h,d.", "I' 1IIII'IIgI'li all' ,,1'..dll"I'd III all (lIssil 1'111'1
I'onlllll-oll HIli PI'(I('.'~~t'S IIsinV" Hit' 01" II\(' oXHlant. At
lI/lnl4' It'r.' 1"'1'111 II I'es, I hI' 1'lImlll1l1ltilill III' III mos[lherk
"',\'If"11 '"1111"1"""'''0 I'esliits 111 Ih(' fOl'm:llioll of lIitri('
11'1(..1(" a~ ...hll\\ II III ('qllallon I.
N! I 0, ~:~ ~NO
fill' \\'h;..11 Ihp Ih"l'mlld,\'lIamil' "lIIIllrlll'llim is l('ivf'1I hy
K.,
I NO I"
IN" 10,)
:.!1.!J,' \1 IIIII'WI'
111 "'111/11"," ~ 11\:0 I, IN", '"Id (0., I 111'1' ill mole fral'-
tlfl"~ III" c'ofl"ll:.dplll j'OJl('f'lItrHtlol1 lIlIit~: It is thp J{aR
l'OIlSlllld , I,!I!(K 1':<1 1(', nlol K', "nd T is the IIbgo!lIte
!I'm[ll'I'allll'P ill I":,
Tile I'alt' o( S() (ornillt ;011 alld it~ I'ate of IIl'com.
)10,,1;"11 ,II'" \'('1'.1' hil('hl,\' Il'm""I'allire-df'pend,'nt. Thl'
lllI','h;II"'", or so rormatioll hils I",t", shllwlI tll 'W('III'
\'Ia Ihf' (.0110" "'J.!' ('haill J't'al' 1 ion f:.!1
(), I M ;;::'~ 20
1M
()
t N,;;::.,.NO IN
'J
, (), ; , N () I 0
A ~1l'Hd\' ',1.,11' 11'1'"lnll'lIt "I' ('Ij II II I iOIl~ :\ Ihl'ollgh !i
\ 1I'ld~ ,III' ("II"" IIII(' I'qlllliioll 1'''1' th.. 111'1 rill" "I' NO
IlIl'rn:dloll, 1>;1'l'd ,," Ih('!)('st 1I\'..;lahl(' klnetil' informa-
I 1t.1I I.f.~)
,{ I NO,
(II
,'). 1(11',,- '..111/11/1(" (N-:) (0-:) /,.:
I 'JO'"I(),,) 'I>
II, /l1,,/,II',',ls/'I',
1.:'111:11 ,1111 ~; it".s"n}('~ ..qllllliJlllln1 for (lXY~(,1I alom
1"1'111:011 "" 1', "m "',\'1('1'11 ",011"'11 II'S, :lIld is valid ollly in
ttlt' Plt',-;t'IHt'.1f 1'\{'lIS.'" :111"
III '1IId,1 i"11 I.. 'i'lil ,,," III :-.:, wllh 0," ~"me of thl'
'"11'01(1'11 '" Ihl' 1'111'1 " 111.,,, (,oll\,pI'It'd lilt" No III eom-
1111'-111111 pl'llt't'~.""I',"" "jI~"d 01\ C'xp(ll'irnt'fltnl (~vjdpn('e H.Joe
,II"" II /II """'"1'" ~ '1'11(' 1'"1,, "f flll'l ,"11'111('('11 lI[lpellrs
I" \'111\ fillm 1,,""1(' d"mill:II,1 al I",,' t..mlwrlltlll'es to
io..illj( JI"I(III(II",' al hll(h Il'm""I'Htllr,,~, iI'" 111'111' t'qui.
lillI'lllnll'l'lIdi1IItIl";,
1,'111' mllsl ~1:t11I1fl.ll \' t rln11111~liol\ f)l'I'('."'..~4'~. lh..~ re~i
dl'III'" linll' :1\.,,\,,1111''' t"o short rol' Ih.' IIxldatioliof
1111111 .,\1111' III 11,lrll~(PII dIlIXld,', th... tht'rnIlHI,\'II:tfT\H'.
alh f.I\\II(,1I "'11('( II' ,Jt 111\\'4'" t.'nllll'l ilttltl'S A... it 1't'~;lIlt.
"" mil"" Ih"l1 -, 1,,10', "I' Iliis l'I'/lI'lioll IlIk,'s pla('p,
'1'1111', :lllholll-(lI \'0, l'ml',"O'I' III'I' IIMUIIII,\' "~[ln'sse" liS
".-'1"1\1""111 ~() ," HilI ('Hndl\l~titlll g'a,~p~ an' prednm
In"lItl~' III till' (01111 "I' :-.10,
~ J )I 1 (J I If' "",011/ ,( f
«(»)
CHEMICAL INGINfERING PROGRESS IV"I ,: N,
.'1
(I)
1'hp nlH.!OI' flldfil'S kl1l1" II Ifl illllll('III,,'lh.' NO, ('mis.
jiolls fl'on1 l'lImhll,-.;tioli prol'e:-:sps itl't' tilp aUH)Unt of
ftXt'tl"';.J. ail' 1I~'wd fot' comhustioll, t tU' hf'al n~h~;L"'~ null
l'f'nHlval I'all's, \\'IIi,'h dt'lin.. 1111' t..n"'l'l'atlll"l'-t inw his-
lory of Ihe ('flmbllstiflll ~asI'S, t l'allspol'l efT(..'IM, and
Iliel Iyp(' all" ('flmpflsilioll, Th,' dll"l'l'lllIlIal ,'Ifeds or
ehllnj!'es ill Ihl's(J flldOl's fill NO, emissifllll'! are sum.
mal'izl'd ill 'I'allll' I,
Th.. e~,'('~S all' h'vel Hlff'..ts NO flll'malioll IhroliKh
IIlIth IIX,VKI'II availability (fir 1'1"11'1;1111 "ith IIitl'o~l'lI,
alld Ih(' I.l'rnpl'l'at.ul'es J'I"...hed III till' ('ombustioll ZIIII".
LflW I'x('e">;Jdr IirillK is kilo\\'II t.o J'I'dlll'" NO, I'lIIi~siflll,
11111 Ih"''''''I',st I"wl p('l'mis,sillle \\'illlllllllllllllll'II(.d 1'111'1.
smok,', all,1 «:0 emisllioll df'IJI'ndll fill Ih.' ('Omblllltifin
(lI'OI'ess alld Ih,~ t.l'PI' III' 1'111'1 11111''',
IIIJ.(h hl';ol r..h'Hsl' rale~ I.'ad 10 1IlI'l'l'as,'d NO, ..mb.
~101I~ 1>1'1'alise III' t III~ ,!xll'l'mt' sl'lIsit ivi Iy o( N(.. forma.
tlOll 1'4'1 Ii i bft 11m alld k i IIl'lil's III ("'Ilk 1'~mpel'lIllI 1'('11, On
Ihe olh,'1' h>llld, hil('h h('al I'l'mflval rates are dl'sirable
Iflr sialifillar,v ("ombllstioll pI'OI'I','S.'S, "f> thl'Y limil th,'
eX"OSIlJ'l' o( th.. l'llmllustioll l-(a~l's to Ihl' hiKhe~1 tem-
peraluJ'I'II. Thus, kinelie limilatiolls III'(' Iml",~ed flllihe
Hmoulliof NO, formed in the IH'fll'I'~S.
1'h,; di,lrillutioll flf (uel an~ ail', :11111 Ilwir mixinll'
with I'flmllll,liflll j(as('s ('an lI'fel'f NO, emis~ifllls, I)f'.
lilll!ralt' "lInllHlalll'f'g" ('I'pal('" 10 ('flIISlime mflst or I h"
fUI'IIIIIII.'r fUI'I-ril'h ("flndit ifills may "f'sull ill rNIIII'iIlK
NO, I'rnisSlflnf>, Similarly, IlItel'IIHI re\'irnllatiflll or
bHckmix;nl(' of combu~liflll I('asps I'l1n dilutt' t.h,' pri.
mllry lIame zone, reducinJ.!' its It'mpernturp, whil'h is d,',
gi..ahle tor IImitinlf NO, (ol'rnation I'at"s. }I 0\\'1'\'1'1', :111
im'reas..d 1"vl'l o( turbulellt'l' 11/'1' "/' ma.v n'SI.\t ill
eilhl'r del'l'l'asinl(' or ill(T/'a~inl( NO, I'missions, dl!-
pentlillK on Ihl' l'onliKllrlltion of thp combu~tion pru('-
ess,
FUl'l t.vl'" alfl'"ts NO. IIIl'rnati"lI ""th throlll('h Ih(.
Ih('orplil'al,lIam,' lI'm"'!1'1I1I1rl'~ IllIlIillallll' (I'oal ,,,ii,
Ifll~', alld thl'oll/(II the rnl!' of I'adiat.ive heat transf,'r
(I'oal od '1('11-'1, Thl'sf' ('lIlIl'll'd (lidors ma,v I"dall('"
('lIl'h 01 h..r, "ut i" j(l'lIt'rlll. 1'01' small 10 inll'l'ml'dilltl'
('ombllsllllll inslalilltioll>!, it is a J.(0(.d "1'1111'.0(-1 hllmb"
tll ..lIlIk N (), ('m issillll (ol'millK lelldpn('i"s ill IiiI' ord,'I':
(,0,,1 ,,"I,'l('as I,r, I, "'01' larl('(' illslallatiolls, limitl~d 1'\".
d/'II('I' IIlIlil'atl'~ t.hal Ihis ordl'l' ma,v hI' I'l'vt' I'sl'd , 1'1'1'-
~lImllhl,v dill' 10 Ihe ~hift in ht'al l'('lelise 'heal !"t'me,,,a'
ratio~,
(2)
(3)
(4)
I r.)
Techniques for reducing NO. emissions
Potentilll ('ombustion conlrol tel'hniqllps (or rI!dlll'-
inl( NO, emission~ consi,sl of modif.villK Ihos.' ('quip-
ment opcl'nUll1f IInd desil(lI (ealures whidl atTl'd Ihl'
l'omhuf>1 IOn parllmetl'rs desnihl'd allllvl', ()II I' sludy has
dl'filled tl1(' most important "1H'I',diIlK 11I0ddil'alioll~ tll
I". low "X('(',", ai.. nrlllK, IWII.~IIIV:" I'ombus!i,,", li,li' Kas
l'('I'IiTliI;d i,,", \l'lIter 11I.i1'1'IIOII, alld l'IIrn"'lIatiolls of
II...". 1!'l'hllillll"s, 1'h,. implll'lalil dl'siKIl (..,1111""1'1 arp
hlll'lI,'r 1'0llfiKIII'ai iOll, lo('a!.ioll alld ,,,,tl'i tw, :11111 I II..
l.vl""s o( 1i1'11IJ.!' :IIIIII'om""slioll IIlPthilds IIs,'d
Th,' df"C'tivl'lIl'ss o( low "~""SS ail' lirllllf is \\'1'11
dOI'IIII1I'III,'d for 1-(11,- all.1 oil ,'IIrrd",sI;IIII, 'Jo It'sl dala
IIn! availlllll" for ('ol1lrnt'rl';al 1'0111 firilll(' "qlllpnll'lIl.
}lOWI'\'''I', 11I1)(II'/lloI'Y dulll I (; I show thl' I'otelltinl of
Ihi~ 1I'('h'IIIIII" i( pl'oll"'ms illVllh'lIl1(' 1'01111'''''1' 1'111,1'
IIUI'II Ollt 1111<1 hl'ld Il'allsfl'l' ~lIl'fal'" 1'111'''''''''" "1111 III'
11\'pl'('(lrTlf',
Two slaKI' 1'11'" 1111 sl illil (;, "lIlIsisl~ "I 1''''1111( all III'
Ihl' (11,,1 "ith sllll~lokhion.."I';" 11":1111/111'" III' I'l'imary
IIiI' ill thl' fil'~1 ~11Iv." alld ill.!"..tillJ.( ~('('IIIIII"I',\' ni.. inlh,'
,"'1'111111 slal(l' III I'IIITll'h't', 11111'11"",1 "I' Ih(' rll"1. III Ihf'
first ~laK", NO (ol'matillll I.' lil1l;t,'d h\' Ihl' IIlIavail
alldll,l' III' "'\'1("11, I(..n..,\'al III' h":lt 1"'1"'1'('11 "lal(l's 1'1'.
dlll'.~S lht" tl'1111)11l'allll'." Hl'hj.'\t'd \\ tWit tll.. t'\('P~S ait,
Februory 1911
-------
700
600
500
i
"k 400
o
z
300
200
TANGENTIAL FIRED
Figure 3.
Effect of
excess air
on NOx emissions
from
oil fired
boilers.
OXVGEN IN FLUE GAS, ,.
I~ addl'd, thereby killetically lilllilllll{ NO formalion,
Heuuetiolls ,,~ hll{h as !IO'j; have Let-n achieved Ly com-
hlllinlC th is kchni'lue wit h low overall exceS!! IIiI' firing
III larlCl' Ifas til"l'd powl'r plallt:-;, The applicatioll of thiR
t!'..tl/lillu!' to eoal tirilll{ is I'xpeded 10 result ill "rou-
Il'ms ,similar to those encoulllered with jU!!t low exces!!
air firillg,
FIliP gas 1"1'1'1 1""lllat illll 10 t he "ombll~1 iOIl zlIne has
Ihe prilll'ipll! plI'ed of 10"'1'1'1111{ "pOlk !lame tempera-
1111'1' Iii, !II, Th.. IIxygell "IIlIeenlrlltioll is aillo lowered,
llild thi.' I,", f"'"l"s r!'dlll'l'd NO, fOl"matioll, Injedion
"f "alt'r "I" I",,' t"I11I"'I",,1 II 1'1' st!'a/ll illtolhe (~Ombu8tion
wile ('all "Iso III"0lhll'e dillilioll ,'11','<'111, 1I0wever, this
tl'l'hnlllUI' ''I'I'''III'S to have limited utility fUI NO.
,onll"ol illillilit,\' l",ill'l" b",'lIllSe of the los~ in thermlll
!'tlkil'III'~', alld (tl" I'osls aH'OI'lal..d wit h steam or wllter
inJ,'elim). 1I0\\,I'VI'r, walt'l' illjedillll IllIIY well ue the
m08t prnmisinl{ techniqll" 11 J) for lowering NO,
..missiolls from slaliollal',\' illl..nllli I'ombu~tion en-
Il"lt''->.
I\H '''I' d,',iv,1I f"lIttl"''';, \'lIl'IalloIiH III NO, emissioliH
hnvo )""'11 ol"I'l'v.,d with dltl"'!,!!1I1 ty,,'" of burllers,
Th,' hll{hl,\ 1111"1,,111'111 ol"'I'IIIiol/; f..allires of eyelone
1"11""'1 ", 1'", "\lIl1Ipl.., "","11 III hlj(h levl'ls of NO,
I'mi",,,,I' III (,,,..I fi,...01 1'0\\''''' 1'IIIIItS, Oil the olher
hlllld, III t '"11.(1'1111.01 firilll{, where tht' furnlH'e illleit iM
Table 1. Major factors affecting NO. emissions.
Change in Effect on
Factor NO. Emissions
Decrease Decrease
Decrease Decrease
Decrease Decrease
Dee re~ se I nc rease
Ilicrease Decrease
COil I '0,1 .GilS Coal ,Oil ,Ges
f)pcrpase Decrease
Factor
E.eess A'r
Preheat Ternper~ture
Hl'at RI''''iI~'' R~t..
HeAt Rf'rIIO",,I R"lp
Backrn"11I1o!
fllel 1 YI'"
f uel Nltro~~(~11 COr1tt'nt
II 1'1 \ 11)1 { ! 'i;' I
IIs('dliS the bllrner, as milch us (iO'; rl'dudioll ill NO,
levels have been reported (J 2). Figure a, I're~umahly,
this is due to the lower peak lIame temperllture" which
re~ult from Kpre/lding out the lIame fronl.
Lower lIame lcmperalurc~ III'" also a basi~ fill'
considering fluidized bed combu~tioll for low NO,
emillKion uoilerR. This techni(IUe, IIclivcly hcinJ{ 1'1'-
sean'hed bolh in thill eOlllltry and ahroad, t'ollsists or
comuusting the fuel in a l1uidized hl'd of solids ,'011-
laining part of the heat transfer suds('e, The very
high heat transfer rates characteristic of thiK lIystem
enllhles maintuining low av..ral{e I'omhtlstor hed tem-
peruturell, typically] ,500-1,HOO"F,llIlIlIidihed bed com-
bustion, however, the oxidation of chemically boulld
nitrogen in the fuel may result ill emissions eXI'e..dinl{
those formed hy the fixation of altllosl'heril' lIit rogl' II
ill ('onventioll.lIl comuu~tioll,
Kinetic model of NO formation
A, II stllrtinjC poi nt for qualll i f~' i III/; alld 1'1'1'<1\('1 illg
some of the comhulllion moddkatloll elrl'l'ls Oil NO,
,'miHHions, II tirst ,gt'nerat iOIl kineti.. mod,,1 was (It'v..l-
opl'd anrl lestI'd, Th., IIIOdl'l ('oll('"rIlS ollly NO fo,.lnll-
tion IInd diKIII'III'III'IIII<'I', ;1." thl~ ('0I1I't'1I! I'al iOIl of 1'(),
ill lIeglijCilJle oodel' ('olllhostioll ('oliditillll'"
Our modl'l of net, NO fOl'lIIation ilillatlll'all(/I,s "om-
huslion is idt'aliht'd hy usilll( prtHnixed, gaseous hydl'o-
I'arbon fu.'1 ail' feed, The 1'l,levllllt f,'utul'es of this
model 111'1' a," follows:
1. One-diml!nsiollal, homol(elleotls loCas phase reae-
lion Kystem
~, Spel'itit'd flllw vl'lo('ity, P 1'1'" II 1'1', and flllW al'l'a
profiles
3, Heat 11'l1l1sfer spl','ifif'd IIpt jOlllllly by
II, lIelit tl'allKfl'l' I'ate pl'IItilPs
h, Ileal t I'll liS.!!' I' t'IIC II il' Je II Is IIlId \\'0111 Il'rnpf'l'atlll'l'
prot1le~
c, GII,o; tl'J1Ipl'ratul'l' proml"
d, (/II"IIl'hillj( ratl' Pl'otilt's
,I. lIeat gl'lIeratioll dl'S!'nbl'd liy t \\'II-S"'I' 0\"'1',111
CHEMICAL ENGINEERING PROGRESS IVol 101, toJo /1
-------
15 20 25
DISTANCE f(lOM COMBUSTOR INLET. FT.
Figure 4. EHecl of excess air on NO temperature profiles.
k'llPlll" "I hl'd,.o""..h,," o,idllllOIl tll ('0, followed hy
( (I ""111111,,,1,,," 10 ('(I,
:, II'ld", II'h i .II''' kill,'! i,'" u"..d I" ",,1('111,,11' NO ,,011-
ITIII t:d 11111:--
,; \11111'1,1., 1'",,11 "'.1.-,:1'''11 of f,,('1. "I)' or flue gas.'s.
II h" I, III"kl" ,t 1"""lId,' 10 ,Inllll"tp Iwo-"llIgl' ('''m-
1.11"lltlll (11 11111' ~;I"" 1""111'111:1111111
'1'11''',111,' I"",,' l'a..l" "1'111,,, m"tl1"l1Iatic;d Ilwd'jl
al t'
PI'lalll'd k,U('!Il'" of tilt' rllel "01111",,1'''" all" NO
fUI 111;1\ 11111 ;lIld dl'I'On'J1nslt ion pl'n('l':-:'~t'....;
:! P,'I"II,'d d""'l'Ipli"l1 "I' tl1l' 11,1\\ of mall'l'IlIl
11,111111 1111' 11.'"11' '
.\ P,'I;IIIo'd d.."nil'liol' "I' Ihp Io,'al II"w wi(hill the
11:1011' illltll,) tht, SlllTHllndlllgs
1'." II", 11l',iI 1!('1I,'ral ilill 1,-, m. l1Iel hal\(' fllel wa~
"",d I" "mlll..I., lI;ilural ~a~ ('''l1Ihu~li''n, ThE' delllile(1
,III'IIIISII'I "I' till,' pl'll('P" h .."ml'lpx, liS is lypiclIl ror
~;h 1'10;",' f,'"" radII III ..hlli!\ ""lIdll'IIS, lIlId"r gteady
...1,111' j'4IIIIIIIIIIII";, Ine latt...('lIldl'flllln~ slf')1s "ppeilt' to
I", t hp 'I'ad II,US or ml'! hall" IIlId ..a..h,," monoxidl1 (an
11I1('..nll'di"te produd I wilh hydr"xyl free rlldH'II!g
11 )!,
('II, I Oil ~ ('II, I II,!)
(7)
('(I I ()" ~ ('(), I II
(M)
I'''''"''I'''IIf
IMO ~
:;)
I-
~
1200 ~
IIJ
~
.
.......--.-=--w= -r= ~. --.::...-
800
400
0'1- EXCESS AIR
40
11.1,1.1111; 1,1/1
-------
-- ----r-
2000
~
METHANE/A'R
5" [MCESS AIR
PRIH£A T TEMPE itA TURE - 5".1(
. 2400
-.-.
-.-e-
--.- --
.-.-.~ --
-.-.-.-
---
/ 'to - - -. TWO-STAGE COMBUSTION
I -.-.-.-.'"':- ~..::::IAf'=:'1= :1'-='-:= :"1"-=
.-8 .00/. FLUE GAS ECIRCULATION
°0 5 10 15 25 ,0
DISTAttCE F"OU co...unol 'NLET. FT.
fi,ure 5, EHects of two-stale combustion and flue .as recirculation on NO temPtrature profilea.
NO
l
!
I
u
it.oo -
~
1200
800
'to
i
400
,0"1'1...1. '1'111" 11111'11' o:,j1,,,<1 11.\' ""nll",l/'r Ilr"l(rllmmlng, Within the 118mI',
Itellt i.. 11"'"011'01 10 move only hy convecfiun in one-
y rlldi-
,iI i011 ,",,1 "'Iii '!I'I II,n, \\ Ilh ,«,,<111\'\ 1(," ne~lected.
Th.. 110:1.-.- ",,,I hell I b.illI!I('e ()(llllIllolI~ must ue inte-
1'1'111('<11« oI.'lermilll' the tCfnpcl'I,tUl'e, thl! gas flow I'nte
,111<1 1111' 1111.11' 1'1';11'1,,,"" "f r'I,'I, (J" ('0, H..O, ('0.., IInu
:'\ ~ II 1""10: 1111' 1'11111'(' Ic 1110: 1 h «I' t h~ ,'''miJll~lol', A~l Im-
)IIi, II ,,,'1"'1111' III "hll h 1111' '! o( the \l'I'~' high lIame \I'IT!-
1"'l'lItlll'I'" PI'lIdlll'e\,1"",.'<1 II
1"'11""'11111,1.. IfIIf'llI'hil1Jj' 1'1111' 1'1'«1111, ill \\'hil'h tiT ,/1
\'III'iI!~ (1'"ln I..I:.!'-. K ,,'(', at :.!,~Otl'l\ ':I.I<1i1i F, 1«
:.!7H K ""C'. ," 1.1;00" I:.!. t:.!fI F 1 I :,'1,1 "I! II tlll'.-1'
CHEMICAL ENGINElRING PkOGlhS I;',' ,/, Ilu
-------
1111\11.-<, I tH' 'II"III'hll\f' I ali' I~ pl'IIpllrllllllal III t hp. fourth
1"'\\('1' III' lhl' "I'~IIIIIIt, t"I1I"..rlllUI'(', \J~i1w thiK quench-
1111( rOI'" 1'1'11111.. 1111.1 u 1'11,,,\101111 pr..t,pat tl'mperatllrl' of
:,:\:\"1\ 1;,011'1'" Ih., rill" III' NO I'lirmlllilln W/IK ('Idcu-
1.11,'.1 1',,1' ~illl(ll,-,;taKI' (,IImt,,,~1 1111\, at exn'KM air levels
"I' II, :", :lIld 10'. T\lII-~lal(' I'tlmbllHtill/l was Kimll-
1.lIed .It ""1'1'11/1 (I'\e,':-t'-' .lil' Ip\'el~ IIf ;)- and l()(~ t with
Ii, sl,,;lal(l' I'~\\"~ ull lit 0', St"'II"d;,I'\, IIIjl'dlOli IIf
all' IIUS n1>td\' at :", 10., IlI,d :W fl" I'PHp('div<'iy, OOW/I-
~trl'am "I' th.. 1"1'01111111 III' prllTlary feed InJ,'clion, Flue
v,'s ,.."",'(',lIlIti,,1I buck illt" till' primary lIaml' zOlle wa!!
'1!!I,datl'd ut {')(t'I'SK air h,Vt'I~ III' fi- "nd 10'; I{pcirrll-
1.1\1"" I':ltf-'" ,,1'111-1111.1 :,0'. 1.','('1'(' 1..~t,,(1.
,\" ~hll\\ II III F, g" ,.' ,I, low I'X",,"~ u i I' fin nl( (i.e"
,1.lIl'hi"I1II'I.!l' :111' ,'lIpply' ""~lIlt" il' I"", NO, emi!!-
""IIK. '1'111' pI'lIk (',,"centralillll>' III' No val'," in the
.11 .1"1' ,,1' 11;>-1 "pm at n';, l,e,i'II; 1'1'111 at :,'" /llId 1,17R
1'1'111:iI 111', "XI'I'S>' air, Thl' "<>I'J'espolldllll( fillUlcllncl'lI-
t rat 1\111." (It NO \'BI',\' III t tit' IIrdpr (If ~;J!) IIpn1 at 0(';,.
1,1~1:!.l'l'm.1I :,'" Jll1d 1.17~ ppm ;,[ 10'; ,'xce~s nir. All
"'~I'IIK',I'd ('11,111'1', Ihi, idl'ull11>d, pn'm'~l'd m
-------
Table 2. Summary of estimated combustion modification control costs for
1,000 MW gas.fired power boiler"',
Capital Eq, Operating
Costs Costs
$1.000
120
0,
120
600
720
23
Control Method
low Excess A,r
Two Stage COlllbusltQn
low Excess Air 1 Two Stage Combustion
Flue Gas Reclrculat,on
low Excess Air I Flue Gas Recirculation
Water InJect'on
Estimated NOK
Reduction. %
33
50
90
33
80
10
"load factor - 6,120 hr./yr.
pr,wesses 1".t"111 i,III) ..apabl., of "0111 rollinK SO, cmis-
~ioliH as wl,lI.
I, ('"tal,l'Ii.. d,','ol1ll"''''1 lOll
:.!, ('''lal,I'li,' r,..I"dlon
a, :-;"n-',Io,,'11I1' III 111'1 I'l'dll".IIj.( .'nvironmcnt
I., S.,It'di,'1' 'n nt'[ oxid,ZIIW pnvir"lIment
:1. Adsor,,1 ion f rt'ad II,n hy Holld"
I, Absorpli"n/rt'adioll by liqllidH
f). Ph~ :-.ic'al ~wpal';lt IOIl~
/0;/11/'''''''1,': Tel'hnolol(y ..ap:d)l.. of I't'moving hoth
SO, and NO,
While tll'! lhcrm"d.I'liami..ally favored de,'ompositi"n
of NO WOlild "rol'id.,II r"lativ"ly simple "'1elhod r "011-
lrollinl( emisSI"n... no ('alalysl Ioas 10..('" foun" ,,!,i..h
pro"IIIt's s,dli..il'nl :lI'tivity OIl l'l'asonablp lemperatllres,
This is so, oIcspilt, thc fad thai 110..1'1' has Ioeen ,'onRid-
l'ra"I.. r('Sf',1I "10 ,n lhis art'a dcvoted to automotive
1" and lloat mosl of this rellear('h hllll
IIsl'd ('11""1 j.(aSl'S fn',' of 11/). ('0,. :01101 S(),' At hil{her
11'111"l'r:olllrl'H ,loar,,,'I,'rist i,' of Iltlloliz..01 hed ('omhus-
111'11, Ih.'n' IIPI"':II'S to lit' S"1111' prol11is" for I'ertjoin
alkllii or :dk"li,"' 1'011'110 aoldilivl's as oI",'omposition
..alaI) sl s , /(;, ,
~oll':-:I.It'('II\'l' l'I'dll('111I11 IllId.'1' lH'l t-,ldudnR' (,olldi~
ti"ns 1111' ""I'll ;II",J,,'d I" Ihl' 1'""1/,,,1 of lIitl'i., IIl'id
tall .~;I' t'''II~''-IIIII,... \\!th 1111:-'1,11 SIIl'('I'-';~. NClb1.. nH~tal
..,IIal,1 ,I, a'" ""," \\ ilh sl,..I, r,'d'lI'lall" aH ('0. II" nllli
('II, ";', I,"t slI"I',,/'I.'d ""1'1''''' oX "I.. may 111,," III' ef
1'."'1111' '1" 1-:"'11 \\ II" ,,"'h a 1'I.laliv..I,v incxpl'lIsive
.."t;d,ISI, " ""II"",,,,..liI'I' l'\.dll,'li,," I,,'o,'ess 'R jlldl{I'd
III 1,1' 1I1I;,tt';1\ I '\'1', ThO' /'1''1'"1'1'1111'111 I'll/' 11(,1 r..,"willl{
1'",,,hll"II,' nll'allS Ihal 1'111".1' I hI' 1'''l11hllRli''lI mllsl he
",lITlt'c!lIlIt IIlItll'l ...ul"...jlllchHlnu.lllC' ail' conditions, or
I hal ('(), II,. "I ('II, 1111 os I I", "ddl'd III the Iltll' j.(as up-
sl/,""I1I'oI IIII...,II..hl'" 1'1';"'1", l-:illlI'r "I'I'/'IIa~h \\'011101
'f''''1I1t III .....,qJlp 1'111 1 "'i:->I 1 III,"; Id' 1 h,,-.:t' ~r"sl':-... &lnd in all o\'tll'~
"II ,J"'T"'"'' ", 1'1.1111 I hl'llIIlIll'lIil"l"II'Y,
111 tilt, 1':1"';1' I If "i'lt'I'11 \ (I I j,dlH t jllrl, anlnllJlli:l is knowlI
tll 1,4' (."p;ddl' Id It'dlll'ill~~ ,'\0 ..;('h'( li\'f'h Irt HII IIX,\'J(f'J)
1'!I/II:lIlJill)l ('11\11111111)1'111 ! /,111 ~ll('h !'t.dlll'tillll flf N()\
\\ IIh \'11 JII", 1""'11 1'I:lI'li...,d I" a "'/',1' limil,'d .'xtl'nl
"' 11,11'1' ,1\ ,01 ,,1:1I11s, 1,"1 I"" 11,,11""'11 l'arti"lIlady ~IW-
",,,fill I" 11;01,', 'I'h,' 1,,,1"111,,,1 ntl/';wIIVPIIPS' "f 11111-
nt"lIl;, 1'''1' II,,,, ~'''' \'41, ,,'dll' li,,"li..s III Ihl' fad thllt il
nl:I,\ .d"'lIllllIlnl1 SO, (.tHIS:'->jHlh in a ('HrHhiru'd pl'4Ices~,
Olh.'r 1'''II'IIIi;d sl'l....til" l'\'dll,'lallls 1'''1' NO IlIdlld.~
II ,,- ,-'/J' ..od II, 1':/' III all Ihl's" "a'I'S, Sllitllh!t>
,0110111 -\,- 11111.,1 I", dl" "1"I'I'd, ;11101 I'I"I'I'S~ ~ondition~
dl'lillt'd
\\'1' "I "III'" 1 ",;ti,'d II", 1'",.,,11,:,1 rt'mllvul of NO,
filII)! 11111' ";1"1'-' 1.,1,".1 ."1 ddr.'II'II('I'~ III ph,\'~il'a11 ('hal'-
;It'll" )',111 ,(It Ii ,I" IIHd"IHlnl' ',1/1', I "fJd"II~HtIOIl tHtT1-
pprattill', ;11111 III:lgIII'tll' '.1/ ,j'l'plihtllt\ of th(' "0111.
1'1111"111.... "II(clIllIlI:lt,'I\.llIl' pll\'-'it;d 1)J'!IPf'l'tif~-'; IIf ~()
11 I .lll, II '/ 1(//1
$1,000
--122
o
--122
118
6
141
Total Costlyr,
$1.000
95
o
95
202
107
144
$/ton NOK
Controlled
-5
o
- 2
12
3
27
fall within lhe I'anl(e of properl ie~ of the oth.'r, mort'
nbundllnt, I'lImponentll of the title I(U~, InveRtnwnt and
operlltinl( cOMts {or physil'al Hep/lrlltion te('hni'lueH
were judl(ell to he pl'ohihitiVt.,
All comnlOlI IId~ol'helltH Wf'I'e ,'onHidered II" pol<,ot illl
1'lIlIdidnteH for rt~movillll' NO, from flue I{IIS, Siwh ad-
HorhentH as Hili"11 ICe I 1221, alumina (;t,/) , moll'l'lilar
HieveM (24. 2fj). char (;,!(j, '.L7, 2N), and inll cXI'hallg'f'
re~inH (It!) J all show Sllnll' I'apal'ity fo/' oxidi?ill)! NO
to NO:!, und then ad~orbinl( the nit/'ogcn dioxide, lIow-
ever, the capnl'itil~H of the~e adHo/'belits are quite low
lit typicnl NO Iluc I{IIS ,'olll'elltrations, Among solid
HorhentH, l'ert:1i II melal ox ideM, pa/'til'lIlal'ly nIanj{/lIII'HI'
and alkalized ferric oxideH I :UiI show \f!chnical poten-
lial, cHpel'illlly in conjunl'tion wilh a rej{encrntivc sys-
Icm with /'ecyele of NO" into the Hue I(as, )Jo\\'e\'e1',
sorhent IIttrition under th.~ severe conditions refjuirt!d
for flue ga~ treat ment is a major tel'hnoloj.(i~al ~lum-
blillj{ block fill' developinl( HIlC'h pl'ocessell.
Of all Lhe potenlial fltle I(I\S 1'01111'01 techlli'llll",
IIIltleou~ IIbllorption syslems IIsinj.( alklilinf~ solilliolis
or IIldfuric al'id appear to ntTe/' lhe mOllt promi~e for
,'onlhined control of nitrogen and sulfur oxide emiH-
Hion~, Vllriotl~ orl{ani,' I\lId inorganic ~omplexinj.( HOIt,-
lion,s that dissoll'" NO \\'I'rc I'onsidered ro/' its I'lIlItro!,
bill wel'" jUdl{f'd 10 have too lit II., ('ap:wity, to del(radl'
I"n ea~ily, to bc lOll v"lallll', or III l'oHl 1,," nltll'h. IIsillj.(
alkaline solillillns II/' Stllforir arid fill' 1'1,"11'01 of lIil/',,-
)CI'II oxide "mis~ions r('qllirt,s al'hit!villj.( c411irnillar ('1111-
("'IILl'alioIiS of NO alld NO, ill the )Clls, Hi 11('1' "t,slll'plillil
of t hI' ('om"i II I'd oxide, ~((),' i~ I he most favorable
1,1/, :12),
l)iff"I'('lIl \\'a,\'~ of jI('hil'l'illj.( slll'h 1''lIimolar 1'01\1'('11-
Iralioll III lhl' tllle j.(as h''''I' 111',>11 ",,"Std"l'ed ill ,It'tail.
Kno\\'tI hnm11jtt'nt'l)lIs or l':dalytH' lI:-.id:ltiHII tl'l'hnlqIlIL"'i
al't' too slo\\' "I' I'ostl,\' for 'l<'hll'l'illl( ,",'h ""IIi 111111:11'
l'olll'ClIll'aliolh ,,1,/1, 'I'h., I"'I'\I'I,~ III' ,\'0, ililo tll<' 11,1<'
~~II" ""pl':II'S III lilT",' I h,' 1"",1 posHibility This 1'1"',1"'11'
of :'-10, ma,l' I", a\" "IIII'II',h,'d 1,,1' oxi,l1zill~' I tll' ""11"1"'-
Il'lIt,'d :'\0 sll't'am 1'1',,0111'1,01 1',1 '111'1'111011, ,'11'111'111,1 I ie,
or d1l'llIi..,d 1't'~'''III'I':.t'"1I "I' I hI' SI"'III 01",,"1'111'111,
lilld,', \'01111';11'1 I" "AI'('A, T,I"" !.al.llraloril's is
"\'lIl1latilll{ II... IIse IIf sl,lflll'i,' al'ld s",,"I,I.illl' ill ('''11-
.I'I/Iclioll \\'ilh NO, r(,I',I'cle illl" thl' 11,11' I(as 1'0' ('1111-
Il'ollillIC bolh So, alld :'\0, ('mlSsilills, Thi, 1"'''\'1'", is
b",..ed 011 I he I'hl'mistr~ III' I hi' !.l'ad ('hal11l...r ,\, 1<1
p/'o~ess IIlId IISI'H Ih.. 1'1'(',\1'1,. :'\0, III IIxiol,Zt' ~O, tll
Hldflll'l" ..dd mist :111111" flll'ln IJII' \' 0, III,sll,'l...d 1,\
Ow Iwid, Thl' l'e4uil't'n1t'1i1 "f Ihis pl'tll'l"S Ihal lhl' I't',
nde ;\in, IIxidizl' Ihl' :-;(), I" Sll 11'11 1'1<' al'id, ill aelelilillll
I;, fOl'milil( ",0" plal'l's -I'I'I'~' sll'lll)(I>lll l'e411il'el\1I'liIs
1111 ,",l'I'II"I,,,1' effic I 1'111',1' ,
Amollll' l'"tl'lItial alkali III' Vl'ld>lJiIlI! Slsll'I11' ",,"
,idet'PII. IhoSf' IIllIizill!! IIm,'\\:III'1' ;II,eI l11a~'I,,',il'm h,-
CHfMICAl ENGINffRINQ PROG~fSS iV", <.I r in ,
-------
Table 3. Summary of estimated flue gas treatment costs for coal.fired power plants.
Investment, Operating Costs
thousand $ . '$/tO" Coal" --Sito'n NO. .
12.0 -0.06 -5
Control Proce~s
Mg(OH), 5clubblf1B
H,50. Scrubbll1jo\
9S'~'.. Scrubbt'r l HII'~nt
9)4/0 Scrubher l HllIenl
lllnewater ScrUblJllljj'
NH, Reduction &. Snubblfl;1""
mils/k.w. hr.
-0.02
17.3 0.17 14 0.06
17.3 0.65. 118 023
8.5 050.. 45 0.18
15.0 0.92 66 0.33
11.7 0.98 77 0.34
4.1 1.02 81 0.36
4.1 0.91 72 0.32
11,5 Redul!lon/CI~us Proces,
Selectlvt' H, Hednctlon" "
r:~tlllytl( n"Cllmposltlon'"
Ii."'" I.OOU MW COI\I Plant. 1",,, ~ I 0,,1
r "'" ga! ",.sulf""latltm wor1h $() ~O"ton <:oal
St,,,,,j,l,d Credits' S ~1) $25'ton, H,SO. ,(I) $14/toll (98%). $8/ton (80%)
HNO, ,I"~ $~O/tufl, NH,NO, (~J $4G/ton; (NH.) ,SO, @ $20/ton
'Sill>!" 'Clubl'..r "mewaler control systt'm with thermal rellenerat.on 01 sorbent.
. Rased (HI c,,'~lyst cost ot iIOO/cu, It.; space velocity 6,000 to 7,000 std. cu. It./hr./eu. It.
droxid,' "dutl,'n~ ,ho\\ the bc,t p..pnllse. A "I)II~('jJtual
1"'OI'l'"S ,'mplp~'III!( M"I ()H '" ig ~ho\\'fl ill Fi!{llre 6.
:-;il\('" pxid,,1111I1 "f S(), to ~llIfllrlt. a,'id i~ npt "pl\uirecl,
II"" PVl'II dl'"i ..,"oil' In su('h prPl't'SSt'S IIII'O!)traRt to the
'1'.1 "" pro~e~s, th(' 1't'4U' ..pml'lItR fpr rel'Yl'le NO" and
IIII-':h SlTuhl,er pm('i"I\('Y "h"uld he Kreatly reduced.
('''mp,I..ed ,,, IlnH'wall'r, a magne~illm hydroxiJl' ~crub-
1'>111( ,.;"lull,," "fT.,.., the potellti,,1 advalltaj{e of easier
"egt'nerllllllil "f the oxide from lJOth the ~ulfite and the
IIi trite fp..med ill the Rcruooer.
Cost effectiveness
('{,...t-I'lrpl'II\'l'IIt..;-;S tllI:JI\'St'S ha\(' been rnadt~ on the
'''"11,,1 (I" hlll,!lIl'S ,'"",,,II'I'l'd ill thIS ~tlld~'. with the
"[",,, (1\'1' tll 1'1'",,,/1' a 1>:\.41, rill' formulatill" our five-
.,"'a.. 1(,", I) 1'1.:11 1'I'('"n\ln"lId"li,,1I 1111 st"tl('"HI'}' NO,
,'rI1ISS1"f\ 1'111111"11] III ;-.:irnplp tl')'lth, Lt)~t.(.tTl'ctIVt'nes~ iH
d,'lil1('d." II", 1:<11" "I' thl' IIlIlual...'"II'II\ ,.",t to the
("II:, ,,1.'\1 '. ','a\, Id"I,'1,1(' I,'dh 'litH''' ha"", ,1I('h a" dllllar~ per
't,," pi 1"1'1",,1"111 I"'al" III Ilids 1''''' k.\\' h... fOJ p"wer
p1;1111:--
'I'Ll' ,\ \';11' I ~tl.(n \\ "... '.l'I('(,It'd ;l~ t ht' nltl~1 rcpresen-
! ill \ j' (t/\t' fill' hl''''''- \'().'d pfft'{'11 \'(,Ill'~~ allal.\'~t"~. The
.Id\ ,llItav,' 'If "1'11'1 llll~'. ,t '"i1l1J.{1t> n'p' \'''it'ldati\'t. Yt\ar in-
't':ld \.f .t ! J nil' 111'1'1 III! ...tll L ;,,, 1 :170 ~(lOO is that I't'a:-1on-
,d,l, ;11'« 111',I[t' f'd'.'l ;I~t" al't' a\;,i]:t!Jlp, and Ih~ ~'flar
! 11'I"t'll 1', -,tlilll 11'1111,\ IlI';I' tu I !'t',d II ;1-" a I"f'al"lime,
t I"dl""( It lit !ddl III
,\~ dhl 11""I'd (':11111'1', In;I)II! ~()\ ""1[0...;'-\1011 snurres
,111'1,1,' 1." 11"",1'1' ~~i'II\'I:III!III, 111111/,,11'1,11 }'(I[I.,)'.I.l, ~ta'
11111',11 \ 111\\111.11 (,Jj11lllhI1l!11 l'I!~illl'.'~ 111 IJIIII'IIIIP gas
11',. 11";/111- ,;1 'II"'; ,(t!li g:l-' )1\,) III., 11111\"11'1 (1.11 ;111(1 snlall
d"IIlI'''!!! "(J!il'~ ,II)(! !II!II (1,11111\1"'11111,"11111'('(':-; in de-
I II'd',III).{ I Ilkt II! II1Qllolf:IIII'I' Th,:-- rt'Jati\'.' ranking
"f t'n]:,",,,lllf] ,~"l[j'I('" \\;1."'; 11111}"llt.d III III' ~hl' ",,,n'e fur
I ~ I ~tI
Th,' !."lltI};I!I',! (I.'~~"I'I 'If "II, !'t'dll\'tllll1 ;Inll ;I!-t~o('i-
,tll',1 ,II'~'" ! (''''j I! 111g' fll,rll 1 tll' .III)I!II :,11 11rl 1'1' 11lJlf'r1tial
(..rll! III fl'! h!!tqlll' ""1' I" 1'~.('I1It'd 111 '1',11,1.,< '!. alld :J,
'''1''',111"11,1',,, " 1.111)11 ~I\\' ,,;,. O"I'd. aile! a I,non
\1\\ 1";il/i!l'd ill'\\'" ,,1.lld 111111,,1' 1,'(11 vas II lid nil firPtl
III ~I ,111.111111\' 1lltp)I' /4,1:111\1.1, 111\'\IIt'II~i\\' t'olnbll:-\.
:,1,111111111'1'11".1"1)'" "-hll\\ \('1\ )/I)lld jlldt'otlHI f(11' abat-
!q' \,( I .'1111"'--,11'11\0( F", 11,111 Iii III}', h"".'\!'I', th,' prob-
!1'11\ Ilf 111'\I'II'1I\II~', l"rl'111\~' L'llnlIH,~tI4'11 rnlldl1inttilln
In hll1ljllt'-{ ;111' 111111 I, /l1'lri' dil1it 1111, ;lIld II n\:l\ 1111('()rnp
"HI MIl Al I Nr .INH NING PMO~ .Rt '>~ ,..'
"
n~Ce"Rfiry to coutrol the NO" sulfur oxide and par-
ticulate emissions for large coal-tired power boilers by
flue gas trE'atment methods. As discusged before, aque-
OlIS serubbing techniques show the oest potential for
such applications on an annual cost basis, because the
by-product credits tend to offset the high capital
charges.
To e~timate the effectiveness of NO, ('ontrol meth-
ods, "composite boilers" have been formulated as the
basi" for this study. These composites take into ae.
count knllwn variations in boiler de~ign, method o( fir-
iUIf and fuel type, on a weighted basis, and estimatl'd
boiler ~ize distribution by cateKol'ies for 1!180. To ar-
rive lit realistic estimates of potential uncontrolled
NO. emissions. the exi~ting emisRio!) factor data for
Inr~e boilers have been combined with pertinent in-
formation gathered in this study. Similarly. in otht'r
(,Htclfories of equipment. "uch as intermediate I.J'JlIf'rs.
the projected 1980 pupulatioll of boi]er~ WII~ liivideJ
illto Rizl' ('ateKories, and lhe Lo," AIlj{eleR County emis-
sion faellir curve data (.15) applied.
Cost-effec(ivenes~ profiles WE're derived both 1111 rc.
gional line! nationwide ba~t's I I wa~ est imated that thl'
potential. completely uncontrolled "tationary NO.
emi""ions in the U,S. would lie on the order of lu mil-
lion ton~ III I!1RO. (luntinuatl(On of t'llrrpnt limited
('ontl'ol pl'Hdices wOldd reduet' thi~ "moulI! t" ahout
1~ mrllion tons IJf i\'O, in lrJRO.) Tu arrive at a given
degree "f rerlul'tion, a "minimum eost path" exists,
whil'h "al'ie~ with the reduction target.
On t he basi g of i ncrea~i ng ('f,gt per tun IIf \; 0, I'e-
mr'I'al, thp contrul of power I.lOil"rs hag the highest
priority, fnllowed by thpse of indll"t ..ial I>"ill'rs, sta-
tionary intE'l'nal combustion engines. und :lltric acid
manufacturing plants, This eORt-pff('l'tIV('lIeSS ranking
of pnpl'ilies is an agr~ement with the "~ource COli.
triiJution" of NO, emigsion sptlur~ discussed earlier,
and e~tablishes the priority ordpr of R&D pl"n~ for
cOllt ..ollillg ~hd ionary NO, emission". Althoul(h dumes-
tic combustion sour~e" are signiflt'ant, nu ('osts hav!'
ber!) includeli for this sectur in a nationwidE' analysis,
I>,'('au"e of the exce~sively hiRh costs estimated fur
th!'i r ~ont 1'01.
R&D recommendations
HU,sI'd IIn the runkiliK "I' "1"(IPllar.,' ~(), I'rnis"ion
~tllln't':-41 thl' f'tt~t-t.'tff:AC'tl\'t't1e~"" asst.'~~nlt'nt IIf NO, ('on.
Id""'JlV 1971
-------
1....1 h"lIlIiqlll'S, IIlId kll"I\'II'd~I' ~1I)lS idellUtll'd ill 0111'
stlld,l' . I " 1111' tin")"I'1I1' ({&II )11:111 )lI'ul(l'am items (HI!
intu fOil I' fJ.\:tJ01' ..al(!~~"rit's:
I, ('01111",,,1 iOIl )lI'O"I'SS sllIdil"
2, l'ol1ll.listi,," 11111' gas 1 l'I'al n1l'1I1 sllIdies
:i. :-\ oIlI-('lIl1IlJlIsl iOIl PI",,"I'SS Sllldil's
,1. :-;lIp'It'l'lll1g "I lid iI's
Wllhill I'at h .'all'I{I" ~', pl'ol{l'al11 i\t'l1Is hHVI' I)(~ell
,11\'1<11'.1 illill lJasi. 1'I'''''IIITh alld a)l)llil'd /{&I> requil'e-
1I1l'IIIs, ')'},I'SI' pl'Ol{l'am ilel1ls ha\'1' IJt'l'lI ol'lll'l'ed illto
Ii\'!' pl'illl'il,\' Idodts, I'lIlIkl'd :II "lIl'dilll( III potelltial a('-
"lImplish!l1l'lI'S III II'l'l1Is of ~(I, )"('n\ll\'al. We haveesti-
Illal,'d Ihal thl' """'1,,,,1'"1 1':\l'llIli,," IIf the (,oln)lle\('
:i\l",II''I1' 1:&11 """.:1':1'" III a ,..sl "I' ~Ihllllt $:10. 10 $4H
;..,11,1111 1I.".ld II'SIlIt III )1111"1111111 )"('dll,'lillll of stalio".
;11":. >~(), ,'ml.~~"I)II'~ II) prp. J!)r,o h'vpl:-- ht~l\Veen thp years
I ~t~i\ a"d ~lIlIlI, 'I'll" hi~~\I'sl pl'i. 'I'il,l' I{& II I'ccommPIHla-
lIon:, an' !t....h'd I ",III\\" : '
E"l""I"" "' :'\(), killl'lu !I,"cll'1
" 1It'li"it,,,,, III' :\\1, ki""ti,'s I" 'II11IhllS1101I pl'lIl'-
t'SS('S
:~. S~'Stl'n111t '" ,llId,I' lIe "III1II"ISI illll n1,,,lifkat iOIl
""'h,,i'l"I'S ill 1''''''1'1 I'lalll hllil.;.."
,I. 1.11 hll 1',11 "1',1' slll.I,I" 111' pl'lIhll'm,; al'lsinl-\" fl'lIm
I'lInlhustinn fTl4ldifit";lt illn \\"prk
:, ;\)lI'III'.IIi,." "f 1,'1';" alld ! IIf NO
klflt'lll:-; III 1"'1111.11...11011 1"'fw,'s~~f'" ;llId fht, ~wrllbhinJ! of
\;( I (Illfti 11:". )~;I'q'~.
Acknowll'dgment
Thi' ;111111,,1"; \\ ;....11 1/: 1'''i.11rt..~ 1111'11' ;tPPI'(','laliuli 1'111'
'';:'''111 li'":1 iii \.1/11.-;11111.-111:.. IIliltli' 1111111''; .;llIdy hy A. H
, "",,,,,,,h"'11 II 1:;,\1. F II '\:1111\1' ;o,,,llIlh,'r I"'''.
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,11,,1 to. I: I' 1:"!,I,,,,'ili..r I, ',II ~I,"h"I1I"III'" alld S,I'S
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IHll'r<-.:. 1'1"'111'1':11111\' 1,1"\11111111111\ t'IIIl1l'oIlIit'.:, 1111111',
111:11 '''''!~lfll/.JI itI11~: \ ,111"\1, I",dl' ,1,::111 i;d 1011'.., OIlId
J'I)', I" nnll"J1,rl :11'1"11"11' 1..1' Illf,q 1\1;1111'11 1";141,, ;1\':lllilbl..
III "', #
Liter ilture I:it~d
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111111'. ..I, NllrltJ.!"" OSldl' ~"rtllllll"li III lIoi/"r 1"11 1"11 IU't"', " ASMI,:
1':&111" It'I.WA.,nl II!tl.III,
la. 1'1'1,.,11'11111, H, I\t:, :ItHI A, A, W~,,.,It'fll"'I~, "1~'I;lIfII' Slnwlul"l'," MrCr'Jlw,
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'101 M"n!lItI, A C.. '''''hi' t'uruI.U!oI""1 fir MdhuIII' 1111 .,(,t MI'CI'cl 1(1'-
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1,1111 'I'llill)
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'p, Md!:>c,,' I" I,d, "":mh'du,,'" IIr (hi.li'l'! "f Nilr"Il"u fru", Slnlitlll:lr\'
:-;.11111'1': tll I,,,., ,'nyt'I., C"UIIly," I.".. "IH~I'Ir'~ Air I'"!lnti",, C'Ulllrll1
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- ,
,~
... "
4
r
, ._~'
~~ ....
W. Bartok received Ills B ~Ilg, in chern,
crtl englneennr. and a Ph,1J In physical
cheml~try Irom McGill UnIversity. HI'
Ita~ heen Wit It r ~so 'Research ...nd [Ilg,
neelll1p' CO, ~II1C(' ] ')57, working in the
'",Ids 01 eKplor;ltory process research,
combustion stlld,es and aor pollutooll
conlrol Currp'lltly, he is a research asso
CI,lte illl(1 prof"ct director 01 I.s~o's
NAPCA sponsored stLJdl"~ of stationary
NO. em,ls';Ion control.
A, R. Crawford lei ell/pel Ills !J.C",!', and
B B A, froln ,It I' University of M,nnesotil,
-------
API Bull. 25J3
February 1959
API BULLETIN
ON
EVAPORATION LOSS IN THE PETROLEUM
INDUSTRY-CAUSES AND CONTROL
Prepared by thc Fvaporatiol1 Loss Committce of the American Petrolcum Institute
I'or gencla) informalion only.
'I his IS nol an API Standard.
AMERICAN PETROLEUM INSTITUTE
Division of Refining
I !WI K Street, N.W.
Washington, D.l'. 20006
Price 81.50
-------
.'OREWORD
Evaporation loss from crude oil and its products has long been a subject of con-
cern to the petroleum industry. Over the years, companies have studied specific
loss problems and have taken numerous steps to reduce evaporation loss. Such
reduction also has helped maintain product quality and promote safety.
The American Petroleum Institute took an important step to coordinate knowl-
edge in this field when it sponsored a symposium on evaporation loss at the Thirty-
second Annual Meeting in 1952. The composite viewpoint of various companies
regarding probable losses from all types of storage was reported as well as a descrip-
tion of the conservation tanks available. The API then formed the Evaporation
Loss Committee. to continue the integrated study of evaporation loss.
The purpose of this committee, representing all divisions of the industry, is to
advance the basic knowledge of evaporation loss and to present methods for its
control. Several bulletins will be issued as various phases of the work are com-
pleted; the ultimate aim is an evaporation-loss manual. The first publication deal-
ing with methods for actual measurement of loss was issued in 1957 entitled API
Bulletin 2512: Tentative Methods of Measuring Evaporation Loss from Petroleum
Tanks and Transportation Equipment. The current report is the second bulletin.
Other bulletins will deal with the prediction of losses from correlations developed
from industry-wide test data.
The principles presented in this bulletin will aid engineers responsible for the
selection and design of storage facilities. Managers who approve conservation meas-
ures wiJI hetter understand the engineers' selections. Superintendents will become
more aware of operation and maintenance needs.
The American Petroleum Institute takes no position as to whether any method,
apparatus, or product mentioned herein is covered by an existing patent, nor as to
the validity of any p"tent a1Jeged to cover any such method. Furthermore, the
information containcd in this bulletin docs not grant the right, by implication or
otherwise, for manufacture, sale, or use in connection with allY method, apparatus,
or product covcrc:-t! by Icllers patent; nor does it insure anyone against liability for
mfringelllcnt of lettcrs patent.
This hullctin may lx: used by anyone desiring to do so, but the American Petro-
leum Institute shall not be held responsible or liable in any way either for los8 or
damage rcsulling therefrom, or for the violation of any federal, state, or municipal
regulations with which it may conflict.
. -lnc 19%-11)5H memhership of the API Evapor.lIlon Loss Committee is recorded in Ap-
pendix VII of this hullctin, as well as the mell1hcI,h " of its four 'lIhcornmittces.
-------
ABSTRACT
Tbc jh.tlOkum indu~try has heen CO;]C('I ned about
evaporation from (rude oil and its produch for many
rar:; In 1 i)<;J, the American Petroleum Institute
fmrncd the EvapOI ation Loss Committee to study evapo-
ration Ir)SS and ways to control it. This bulletin,
prcp~IITd h~' th~lt cOInmittcc, will aid superintendents,
lIIanagu:" :, ',j engineers in earrymg out an effective
loss-control progranL When loss problems arc ade-
tlu than directly proportional
to vapor volume and daily atmospheric-temperature
change.
For storage of petroleum and its products, the indus-
try can choose from four basic types of tanks, fixed-roof,
floating-roof, variabJe-vapor-space, and pr~ssure. Each
design meets specific storage .needs. Selectmg the most
economical tank often reqUIres careful study of the
different types. For each tank, effective Joss control
depends upon accessories such as breather valves and
automatic gages. To maintain effectiv.:: control, the
tank and accessories must be kept gastight. Choice of
paint <.:0101' is also an important factor.
The operating procedures used in production, refin-
ing, transportation, and marketing are all important in
controlling evaporation Joss. Prevention of leaks from
glands, valves, and fittings should be common tl) all
branches of the industry. In production, control of
temperature in the gas-oil separators and in the emul-
sion-treating equipment is necessary. In refining, opera-
tion of treating plants, sewers, ponds, and open separa-
tors require special consideration. In transportation,
careful scrutiny of the methods for loading and unload-
ing is essential.
Control of evaporation loss requires that continued
attention be given to operating procedures and main-
tenance of equipment. Conservation equipment some-
times becomes less effective with age and an evaluation
frequently reveals that modernization would pay. These
factors demonstrate the need for organized programs
for Joss control. Only in this way will the necessary
concerted attention be given this important subject.
-------
INTnOnUCI'JON
1\'11 {)klllli I~ ;11' ..IlpOrl;lnl n, will give aUrac-
11\ c' l'COr,OJ1],c I durn. To he most elIcclivc, conscrvation measures ,>hould be based
111'011 .111 Uild"lst;mding of sources of loss, Llclors
-------
CONTENTS
CHAPTER I--SOURCES OF EVAPORATION LOSS
A. Loss in Storage
13. Loss in ProLluction
C. 1 ass in Refilling
D. I.oss in Transportation and Marketing
E. I;alsc Indications of Loss
CHAPTER 2--FACTORS AFFECTING EVAPORATION LOSS FROM
TANKS
A. Tflle Vapor Pressure of the Liquid
11. Tcmperature Changcs in the Tank
C. Tank Outagt~
D. Tank Diameter
E. Schedule of Tank Fillings and Emptyings.
1'. Tank Condition
G. Type of Tank
CHAPTER ]---TANKS AND EQUIPMENT TO CONTROL EVAPORA-
TION LOSS
A. Fixed-Roof Tanks
B. Floating-Roof Tanks
C. Variable Vapor-Space Tanks
D, Presslllc Tanks
E, Vapor-Rcl'ovcl y Systcms
r Othcr Ways to (:ontrol Loss
CHAPTl~R 4-----PR()(TDlJRES FOR CONTROLLING EVAPORATION
LOSS IN OPERATIONS.
A- Production of ('flldc Oil
B. Relining
(:, Transport:ltion and Marketing.
O. Conclusion
APPENDIX 1- --DEFINITIONS AND SIGNIFICANCE OF FUNDAMEN-
TAL TERMS
A. Vapor I',,'\SUIT of a l.iquid
It. T'IIC Vapor 1'1 esslII c of a I.iquid
('. Reid Vapor Pressure of a Liquid
I). l'arl,,11 I'Il'SSIIIC of Vapor
I:.. S:ltur:lIIOIl or ;1 Vapor Spacc
". I>JfIU.SIOII ill a Vapor Space
(t. V:I[I<'I i/alioll
II, ('ondcns;ltioll
I. ('011<1 uction
J. ('ollvcctioll
K. R:uli:llioll
7
PAGE
9
9
10
10
]0
10
12
12
]2
13
13
13
13
13
14
14
16
19
23
25
25
26
26
27
27
2H
21)
2tJ
21)
29
29
29
)0
30
30
30
30
30
-------
PAGE
APPENDIX II-DERIVATION OF BREATHING- AND FILLING-LOSS
EQUATIONS
A. Ureatbing Losses
B. Filling Losses
RLFFHENCI':)
i\PPENDIX ]If-GENERAL INFORMATION
Symbols and Abbreviations
Conversion Factors
FIG. J-- Temperature Conversion Chart
APPENDIX IV---PROPERTIES OF PURE HYDROCARBONS
TARLE 1 -Properties of Pure Compounds.
TABLE 2--Density of Light Hydrocarbons at 60 F
APPENDIX V--V APOR PRESSURE CHARTS
FIG. I--Vapor Pressures of Gasolines and Finished Petroleum Products,
1 p:,j to 20 psi RVP
FIG. 2-- Vapor PI essures of Ga~olincs and Finished Petroleum Products,
I psi to 7 psi R V l'
FI(;. 3- Vapor P:cssurcs of Gasolines and Finished Pctroleum Products,
.'i pSI to 14 psi RVP
FIG. 4-- Vapor Pn:ssurcs of Gasolincs and Finished Petroleum Products,
12 p.ii to 20 psi RVP
FIG 5 -Vapor Pressures of Crude Oil
APPENDIX VI--MET~.oROLOGlCAL DATA
TABLE 1--Sobr Data, United States
TABLE 2-501ar Data. Canada
T ABLF 3-Average Atmospheric Temperature, Degrees Fahrenheit,
Unift:d States
T ABLF 4---Avcrage Atmospheric Temperature, Degrees Fahrenheit,
L:m a da
TABU: 5--Averagc Wind Speed in Miles per Hour, United States
TABLE ()--Avcrage Willd Spced in Miles per Hour, Canada
TABLE 7--AvcL1ge Precipitation in Inches, United States
TABlE R--Averagc Precipitation in Inches, Canada
FH; l---SilD\V .1I1d Tcmperature Map of the United Statcs
TAm I': ()--Awrage Snowfall in Inches, Canada
APPFI':D\X VII
('OI\1MITTFF MEMBERSHIP, 1956-195&
( 'uf1Jmitkt: un l~v
-------
EVAPORATION LOSS IN THE PETROLEUM INDUSTRY-CAUSES
AND CONTROL
CHAPTER I-SOURCES OF EVAPORATION LOSS
EvapOi ation Ims is the natural process wherchy a
liquid is nmvcrteu tn a vapor which suhselluently is
lost to the atmosphere. The liquid may he unconfined
or may be endoseu in a container such as an oil-storage
tank. By uelinition, evaporation loss occurs only when
the vapors reach the atmosphere.
I:"aporation loss is common to all branches of the
pdr "I ."11 industry. Because tanks are used similarly
tlll"u~I\(IUI the industry, sources of loss from tanks arc
di,cussI'd fir,!. Other sources of evaporation loss asso-
ciatt.:d Ilith operational features of each branch are then
considered, To further emphasize true sources of loss,
ctlildition, which can falsely indicate loss are also dis-
cusscd.
t\. I,u,,'" in SIClra~c'
SIX ~ IIld, uf ev,lporalion loss occur 1'1'0/11 pClrolunn
ill ~,")r,tf~I' hreathing lo,s. standing-storage los\. filling
1,1\\. "lI1p(vill~ loss. welling Ims, n':irillflg 100s, l'lo:lling-rouf tan\..s ;dlllo~t eliminate
v"l'0r '1'0111',. and liuk or no bre;lthing loss occurs past
(hl: 'c';,)."
Sldll"i"g-S(tJr(/~(' 1".1.\',' V"por frolll tanks, which re-
wll\ flOll1 1';IIISCS olhn 111;ln hre;lthing or change in
li'I"lei kvd. is ddirlL'd ", s!andin).'slor.lgc loss, hlr
11();I(lnJ~ "ltlf Link", till' !:I1r.est potl'ntl;" ,ource of stand-
iflg-wlfuge loss IS attrihuted to an imp'opl:r fit of the
seal and shoe to the shell. This condition exposes some
IiquiJ surface to the atmosphere; wind affects this source
of loss. Also, a small amount of vapor may permeate
through the flexible mcmbrane that seals the space
between the shoes and the roof. The permeation of
Ilexible membranes, or absorption in liquid seals, may
also be a source of loss from variablc-vapor-space
tanks. Other sources of standing-storage loss are vapor
escape from open hatches or other openings, glands,
valves, and fittings.
Filling Los:;': Vapors expelled from a tank as a re-
sult of filling, irrespective of the exact mechanism by
which the vapors are produced, is defined as filling loss.
This loss is common to all types of tanks except the
flouting-roof tank and closed-system pressure storage,
such as for liquefied petroleum gas (LPG). It occurs
when the pressure inside the tank exceeds the relief
pressure. For fixed-roof tanks, the relief pressure is
low, therefore the filling loss is relatively high. Filling
loss from pressure and variable-vapor-space tanks is
somewhat less because these tanks have added vapor-
storage capacity. The pressure tank also promotes con-
densation of hydrocarhon vapors during filling.
bllptyillK Loss: Vapors expelled from a tank ::Ifter
the liquid is removed is defined as eniptying 1055. Be-
cause vaporization Jags behind the expansion of the
vapor spal.:e during such withdrawal, the partial pres-
sure of the hydrocarbon vapor drops. Enough air enters
Juring the withdrawal to maintain total pressure at at-
mospheric pressure. When vaporization into the new
air reaches equilibrium, the vapor volume exceeds the
capacity of the vapor space. This increase in vapor
volume causes the expulsion.
Emptying Joss is common to all types of tanks ex-
cept the floating-roof tank and closed-system pressure
storage. Fixed-roof tanks arc lIIost vulnerable to this
loss. Pressure tanks anJ variable-vapor-space tanks are
less subject to this loss but will encounter it if the vapor-
storage capal:ity is exceeded.
In the loading of transportation vessels the definition
of emptying loss is restricted: The transporter con-
siders emptying Ims to be only that portion which
evaporates into the vapor space of the tank during the
actual withdra",al, that is, between the opening and
dosing of the gages.
WI,tti,,~ I.oss: Vaporizalion of lilJlIid from a wetted-
lank wall, exposed wlK'n a Iloating roof is lowered hy
withdraw:!! of IIlluid, is ddined as wetting loss. This
soun.:e of evapor.tllon loss is small.
9
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.----.-
.-----
EVAPORATION LOSs-CAUSES AND CO!'-lTROL
- -~----- -- --
-.---
10
Boiling Loss: Vapors ~xpeUed from a tank as a re-
sult of boiling of the liquid is arbitrarily defined as boil-
ing los5. Boiling loss may occur from any tank. The
fixed-roof tank is more subject to this loss than the
pressure tank. The earliest floating-roof tank, the pan
type, is especially vulnerable to boiling loss. because
beat is readily conducted through the roof dlfectIy to
the liquid and no vapor-storage capacity exists under
the de.:k.
B. Lofis in Production
Production entails three operations which contribute
w evaporation I~)ss: gas-oil separation, emulsion treat-
109, and lease-tank operation.
10 gas-oil separation, the oil may he rich in light
components, which later arc 105t from the usual fixed.
roof lease 1,lOk. In a recovery system, butanes and
pcntanes may not be completely extrm:ted from the gas
and may be lost. A true evaporation loss occurs when
the gas is flareo or vented. In addition to the loss in
crude-oil volume, the API gravity is decreased.
In emulsion treating, heat is applied and released
vapors may be vented. Also, the crude oil reaching the
lease tank at elevated temperature contributes to the
evaporation loss.
At the lease tank, splashing may occur as oil is in-
troduced; in such cases vaporization and evaporation
loss are accelerated. Dark-colored tanks contribute
further to evaporation loss.
C. Loss in Refining
Relining involvl:s three operations which arc sources
of evaporation loss: treating and blending in freely
ventcd vesscls, such as an agitator; pressure systems
which may leak; and sewers, ponds, and open sepa-
rators.
Use of air :-lnd agitation can result in h;gh-evapora-
tion los5 frum vessels which are not part of a closed
system. Swcetening naphtha in agitators and blending
volatile components in a semiopen vessel are potential
examples of this source of evaror~llion loss.
Pressure systems, common to refineries and natural-
gasoline extraction plants, may have sources of evapora-
tion ]o~s from leaking exchangers, glands, valves, and
fittings. Hydrocarbon vapor may \t'ak directly to the
atmosphere. Also, liquid may leak and evaporate rap-
idly if vol,1til« at the operating temperature. Besides
outward leaks, inward leaks of air. such as at pump suc-
tll)J1!> , are sources of loss hecause this air becomes at
least partially satm.lted ltcfore wnting.
Sewers, ponds, amI open scpar;ltors are sources of
cvapof
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------~- -- ------ -----
SOURCES OF EVAPORATION Loss
-----
are not in the full or empty condition which is assumed,
unrealistic losses or gains may be indicated.
Inaccurate Calibration of Meters: The inaccurate
calibration of meters can result in apparent losses,
which may be attributed incorrectly to evaporation-
or in apparent gains which may conceal actual evapora-
tion losses.
Physical Changes in Volume: Certain processing
operations, such as cracking, polymerization, and the
II
.._---- - --------- ---- ~- ---
blending and separation of light and heavy stocks, re-
sult in physical changes in volume even when full cor-
rection is made for changes in temperature. For ex-
ample, in a cracking process, where small molecules are
produced from .large ones, the products will occupy a
greater volume than the charge. In a polymerization
process, where large molecules are produced from small
ones, the product volume shrinks. With such volume
changes API gravity always changes but the total
weight, before and after the volume change, is the same.
-------
CHAPTER 2-FACTORS AF}~ECTING EVAPORATION LOSS FROM TANKS
The total amount of evaporation loss depends upon
the rate of loss and the period of time involved. Primary
factors afTecting the rate of loss are: true vapor pres-
sure of the Jiquid, temperature changes in the tank, tank
outage, tank diameter, schedule of tank fillings and
emptyings. t.lnk condition, and type of tank. Satura-
tion and diffusion eITccts arc only a p;lrl of the l11echa-
nJsm of the loss and are .:\assed as dependent, or second-
ary, variahks. Although quantitative-loss relationships
for the pnll1dry fadors ;m: not yel aV;lilablc, a fair un-
delst;mding b.lscd on theory .1Od pract iee C;1I1 be gained
by consid~1 iug the l11ecilaui'illl pC loss from fixed-roof
tanJ...s. \Vlth Slll'" und('r'l.lndl11g, the adv;llItages of
floallllg-roof, \'arl;\bic-vap\}I"-~pae\" and pressure-t;1IJk
systems will r('adlly he apparent.
A. True Vapor J'1"(~!lurc uf thf" Litl'dt!
rr ue ";'POl prl'ssun' aiTects the rate of Ius': hecause it
i:.; the basic forn' causll1g VajKJrlzatHJlI. It varies with
liquid c(lmposition ;Inu tl'mpcrature. True vapor pres-
sure at storage temperature is al! important. For hydro-
carbon mixture~. this pressure decreases with evapora-
tion hccllIst: of the change in Iicjuid composition. True
vapor pn;ssure usually is determined from correlations
relating it to ReI(j vapor plcsslire (R YP), Such rela-
tionship~ are illu"traicJ in nomogra\1h fOlIO in Appen-
dix Y.
The eITect (If trw: \':Ipor pressure on r :1h' of hlcatlung
los:; from a fixcd-roof l.l1lk invulves ;tt lea<;t 1\\'0 internal
'consldl'J"atjo/1': --Lhe s;llulOItHm nl:ICt'llll.itinn and the
dlfTusitln and convectr!>n Lll'tOr. The !1I,IXinlllln con-
centrOltiun d hydWt ;'1 hons which com h: present in ex-
pelled vapol, kno'..m as the saturation concentration,
innca.-;cs in dircct proportion 10 trul' v:ll'0r pressure. It
foll\lwS lhat If vented V;II"1,'1 s were fullv s;ltmated,
cv:'pl)ration loss wOlliJ iIlU\'.I".L' r;lp:dly .\~ II Ill: vapor
pressnre appro:lches Ih~ UIII.. ,ciieving pressnn: (a boil-
Ing ("(muIL,H1). However, ;lI1othn rnechani:;IlI--the
ditfuslon :Jnd cOl1vr:ction of hydrocarhon vapor from the
liquid SUI face tllrough the VarOl sp:1l'C is Ilk) slow to
fulJy saturate it. Experiencc shows that vapors vented
during normal hreathing are 'Isual!y only HO per cent to
90 per cent saturated. Thus, the driving f(lrce to over-
come resi~tancc to diftusion factors and conveclion
through the vapor sp:lce is olle ()f the r:olltrolling factors.
Such driving force can be k,okcd upon <1<; being the
true vapor pressure of the litjuid minus the p~lrtial pres-
sure of hydrocarbon;; In the vapor space. As trill' vapor
pressuIe rises. this driving force would ri.',e in direct
proportion if perccntage s~liur:ttion in lile vapor spae.;
rcmains Uln\tll1l. Thus, l-,oth the satllraljol1 considera-
tion ..nJ l11e diITusion ;md convection c()lJ\ideraliolJ sug-
gest that actual loss is at least directly proportional to
rising true vapor pressure.
Filling or emptying losses from fixed-roof tanks are
directly proportional to increasing truc vapor pressure
because of the relationship bctween true vapor pressure
and saturation concentration.
This concept docs not apply when true vapor pres-
sure exceeds the absolute tank pressure because boiling
occurs and losses may be large. Then, the main con-
trolling factor is heat input.
I n terms of total loss over a period of time, the effect
of Ir ue vapor pressure depends upon the composition
of thc stock. For example, two crude oils of identical
true vapor pressure may weather at difTcrent rates. One
crude oil may contain a rclatively high per cent of
volatile propane and ethane; for a specific starting loss
rate, the vapor pressure will drop rapidly and the loss
rale will drop shortly thereafter. The other crude oil
m
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---------
EVAPORATION-Loss FACTORS
- - --- .- .--
13
----------~------- ----- ~---
ably will be somewhat less than directly proportional to
the increase in atmospheric temperature change.
C. Tank Outage
The volume of most vapor spaces is directly propor-
tional to outage-the height of the vapor space. For a
fixed-roof tank, higher outage means greater loss be-
cause the larger volume will breathe more. However,
when outage is increased heat input is not increased in
direct proportion. Heat enters the vapor space through
the tank wall, the area of which increases in direct
proportion, and through the tank roof, the area of which
remains unchanged. Furthermore, with added height
of vapor space. resistance to transfer of hydrocarbon
vapors from the liquid surface to the vent increases.
Thl dore, the average concentration of hydrocarbons
in "r,Hcu vapor should fall. Experience has confirmed
that loss will increase less than directly proportional to
increasing outage.
I). Tank Oiumctcr
Tank diameter infiuences the volume of the vapor
space and the liquid-surface conditions. Breathing is
less than directly proportional to increase in vapor vol-
ume because of the less than proportional increase in
area for heat tram.fer into the vapor space. Further-
more. increasing diameter should reduce the tempera-
turc rise of the liquid surface because the rising hot
stock, in contact with the tank wall, must spread in a
thinner film over the surface area. Assuming constant
tank height, total breathing loss, therefore, im:reases at
a rate less than directly proportional to tank volume.
E. S.'h."clulc flf Tank .'illings ancl Emptyings
Owr a period of time, the frequency of stock turn-
over and the average outage affect total loss. Opera-
tions that promote high outages may result in relatively
high breathing losses. Fillings and emptyings scheduled
to compensate the daily temperature changes may re-
duce breathing loss. The time interval between empty-
ing and filling may have a significant efTect on loss. For
a system of tanks connected with vapor lines, simul-
taneously filling one tank while emptying another main-
tains the vapor-storage capacity relatively constant and
filling loss is reduced.
F. Tank Condition
Tank condition is another factor affecting loss rate;
however, quantitative effects cannot be predicted. Open
vents result in high loss when gusty or turbulent winds
cause rapid pressure changes in tanks in which volatile
liquids are stored. Rapid breathing occurs as short
putTs. Any hole in a tank roof, diaphragm, seal, or ac-
cessory results in the same type of loss.
Where there are two or more openings in the tank,
108s is further increased. Pressure differences, which
result from wind or thermal etTects, cause a constant
/low of air through some openings into the vapor space
and an outflow of vapor through other openings.
G. Type of Tank
The type of tank or storage system will affect the
evaporation loss experienced. The amount of loss de-
pends upon the volume of the vapor space available
and the pressure limitations of the equipment.
If tanks have their vapor spaces interconnected,
vapor-space volume can be controlled to a liIt1ited ex-
tent by scheduling fillings and emptyings, where feasible.
If the vapor space is allowed to change volume at
constant pressure, breathing loss can be practically
eliminated and filling loss can be reduced. The extent
of the reduction in loss is dependent upon the amount
of variable vapor space provided.
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CHAPTER 3- TANKS AND EQUIPMENT TO CONTROL EV APORA TION LOSS
The industry may choose from four basic types of
tanks for storage of petroleum and its products: fixed-
roof tanks, floating-roof tanks, variable-vapor-space
tanks, and pressure tanks. Each type is designed for
specific storage requirements, the actual storage pr~b-
lem should determine the type selected. In many 10-
stances, the most economical tank can be selected only
after a detailed study comparing loss from, and the cost
of different tanks. For stocks having a low true vapor
pressure, less than 2 psia" the fixed-.roof t~nk generally
will be the most economIcal selection. For stocks of
motor-gasoline .- _lOge of volatility at high throughputs,
the floating-roof tank generally will be the best choice,
but at lower tin ollghputs the variable-vapor-space tank
generally will be octtcr. For stocks which boil at at-
mospheric pressure and storage temperature, pressure
tanks are best generaHy; however, in some cases use of
the fixed-roof tanks in conjunction with a vapor-recov-
r:ry system may offer more advantages.
The tendency to boil in storage is a function of vapor
pressure, altitude, barometric pressure, and liquid-sur-
face temperature Maximum liquitl-surface tempera-
tures vary throughout the United States. For the
indicatcd tempcr,ltIlreS, the maximum Reid vapor pres-
sures (RVP) of stocks which can be stored at atmos-
pheric pressure without general boiling (but at the ex-
pense of high-lose; rates) are:
Maximum
Liquid-
Surf.ice
Tempera-
ture .
( Degrees
Area Fahrenheit)
West Coa~t ItcOIl'crcll by Pacific Ocean) 80
90
Maximum
Reid Vapor
Pressure.
( Pounds)
18
15.5
Guli Coa.~t, Atlantic Seaboard, nnll
northern Middle WC\t
100
110
115
120
n:'l
11.5
11
10
Mid Conliu<:'1I1 "Ie~ and arid Sourhwc~(
. The lirnii' 11111'.1 he reduced for h1c,Itinns al higher ;tltitudes 10
nccount f<>f lower I,;tr<>metric pressure,
Effective IO~~'l'Olltrl)1 operation of each lank is de-
pendent upon certain accessory items. such as breather
valvt's and :iutom;ltic gages. Continued effective opera-
tion is dependent \lpon a program to maintain the tank
and accessoric~ in a gastlght condition.
Choi,'c of p;,int color may hc an important factM in
reducing 105s In special instances, Ims may be redu~ed
by use of a floating plastic blanket; or, by emplo~mg
insulation, a ~haJjng device, watcr sprays, mechanical
cooling, or by burying the tank. In some cases, it may
be possible to Icdul'c loss further by specialIy schedul-
ing fillings and emptyings.
A. Fixed-Roof Tanks
The minimum accepted standard for storage of
volatile oils is the fixed-roof tank. It can sustain an in-
ternal pressure, or vacuum, .of only .an ounce or ~wo per
square inch. Being susceptIble to sIzable breathmg and
filling losses, this type of tank is u~ed m?st .frequently
for services which cannot economIcally Justify a con-
servation tank.
Design of Tank: The fixed-roof tank, the predecessor
of cons~rvation tanks, came into being during the early
days of the petroleum industry. Wooden barrels were
used at first, but they could not keep up with the rising
flood of oil that poured from the Pennsylvania wells.
As production increased, open pits and diked areas were
used, but they were hazardous. Wooden tanks, caulked
with oakum and held together with iron hoops, first ap-
peared in 1861. The capacity of these tanks ranged
between 500 bbl and 1,000 bb1.
The first iron tank with a wooden, gravelled roof ap-
peared in 1864; it provided larger and safer storage.
Shortly after the Civil War, bolted. and riveted-steel
tanks came into use. They ranged in size up to
35,000 bb1. After 1915 capacities were increased a!ld
in 1919 the first 80,000-bbl tank was erected. The In-
troduction of electric welding, in 1923, made possible
the fabrication of welded roofs and bottoms. The
welded tank was introduced in 1927.
Fixed-roof tanks built today usually are welded
throughout, but many riveted tanks are still used and
bolted tanks are common in the smaller sizes. Whereas
the seams of welded tanks are almost inherently gas-
tight, the seams of bolted and riveted tanks freque~tly
require additional maintenance. In some areas, partIcu-
larly on leases where corrosion is a problem, wooden
roofs, which are seldom of gastight construction, are
still in use. Loss from these tanks is much greater than
from steel-roof tanks.
If a fixed-roof tank is found to be the best type for
a particular storage problem, careful consideration
should be givcn to the size before the final selection is
made, Bccause the loss rate increases significantly with
olltage and tank diameter, the use of the smallest tank
possible for the given storagc requirement results in a
minimum loss. Por further insight as to the outage and
diamcter effects, refer to Chapter 2, "Factors Affecting
Evaporation Loss from Tanks."
Maint('mmce of Tank: To maintain a gastight con-
dition, tanks should be inspected at regular intervals
and repaired as necessary. The frequency of inspections
usually is determined by experience. Riveted-roof
tanks, because of their greater tendency to develop
leaks, should be inspected more frequently than welded-
roof tanks.
14
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--------- --~,----
Ev APORA TION-LoSS CONTROL
When the tank is under pressure, five ways in which
leaks may be detected are:
1. Observation of heat-wave-like trails of the escap-
ing vapors.
2. Hearing the hiss of escaping vapors.
3. Smelling the vapors.
4. Use of gas testers or "sniffers."
5. Applying soap solution or linseed oil to seams.
Also, stains on the painted surfaces frequently indicate
leaks.
Design of Accessory Equipment: The fixed-roof tank
has several openings in roof for venting, gaging, and
sampling. To maintain a gastight roof, accessory equip-
ment of a gastight design must be provided for these
opcn':J,'s
1 ,e accessory for the vent opening is called a
breather valve, pressure-vacuum relief valvc, or con-
servatioll vent. When operating properly, this device
prevents either the inl10w of air or the escape of vapors
until some preset vacuum or pressure is developed.
Mo\t oreather valves, especially the metal-to-metal
types. aIlow somc leakage below the pressure or vacuum
sctting. A tight breather valve is important in reducing
evaporation loss. The actual magnitude of the savings
will depend upon such factors as vapor pressure of
stock stored, weather conditions, paint color, and al-
lowable working-pressure range. However, the savings
realized usually will pay for the installation. The
breather valve also contributes to safe operation by
keeping the tank vent closed to the atmosphere most of
the time.
The pressure and vacuum settings of a breather valve
are Jictatcd by the structural characteristics of the tank
and should be within safe operating limits. A certain
amount of pressure and vacuum beyond these settings
is necessary to overcome pressure drop in order to ob-
tain required flow. Proper size and settings can best be
determined hy reference to II PI Std 2000: V en/in~
II /ll/osplreril' and I.ow-Prc.\'suf(' Storage 7'(/"~.I' (l9CiH)
awl 10 the manufacturer's lank data determined in ac-
cordance wilh this publication. The pressure ~etting
for vent valve, to he installed on large lanks constructed
in accoruance wit h A IJI U D. Sfl('ci!;mlio/l for /.ur~e
Welt!t't! I'rot!u('(iol/ T(JI/~\' ( I (57) usually is limited to
j lIl. because roof plates will start to shift when the
pre,sure rises lI1uch ahove I 01.. For small tanks, and all
lank, having special struclural fcatures, the pressure
range can he increased in accordance with the manu-
faclurer's recommendat ions.
Breather valves should be designed to give:
I. High-flow capacity at relatively small pressure or
vacuum above the setting.
2. A gastight st'al.
1. Freedom from stickinr, or freezing,
4. Easy ;\ccess to all r;lrts for inspection and main-
tenance.
15
Diaphragm and liquid-seal valves have less leakage
t~an metal-to-metal types. For dependable service,
diaphragms should be resistant to tank vapors.
Open vents of the mushroom or return-bend type
should not be used on fixed-roof tanks storing volatile
oils as they permit high loss. These vents are merely
hooded openings equipped with protective screens. The
opening is turned down to prevent any blockage by ice
or snow.
Venting accessories sometimes used are: flame ar-
restors, flame snuffers, and flash screens. They usually
have little effect on vapor loss except when they are
installed bctween the tank and vent valve and must be
removed for cleaning.
Some vapor loss is inherent in manual gaging and
sampling methods which necessitate opening a tank to
the atmosphere each time these operations are per-
formed. This loss can be minimized through the use of
automatic gaging equipment, double-closure gaging
locks, and a system of thermometers and sample valves
in the tank shell.
Accessories which help to reduce evaporation loss
from lease tanks include:
1. Pressure-vacuum thief hatch and vent-line valve.
2. Automatic-closing valve in the equalizer line which
closes when the gage hatch is opened.
3. A diagonal-slotted downcomer type of fill line to
minimize free fall and splashing.
Muilltenallre of Accessory Equipment: To maintain
accessories in a gastight condition they should be in-
spected and restored periodically. Pallets of the metal-
to-metal breather valves which become warped in serv-
ice must be machined to restore a gastight fit. Defective
diaphragms of diaphragm breather valves should be
replaced.
Liquid-seal breather valves may be affected by dilu-
tion or loss of liquid and may have to be inspected and
maintained more frequently as determined by experi-
ence. A loose fitting gage-hatch lid can be made nearly
gas tight by replacing the gasket or by machining the
seating surface.
Flame arrestors and l1ash screens can become clogged
with dust, rust, and ice. Such obstructions in the vent-
ing system can calise severe damage to the tank from
excessive internal pressure or vacuum. These acces-
sories should be inspected and cleaned frequently.
Choice of I'aillt: Tank painting is important in re-
ducing evaporation loss as well as in preserving the
tank. An adequate paint program, using reflective
paints, will minimize the heat input to the tank by re-
ducing the metal temperature of the tank.
White paint is a simple and effective means for re-
ducing evaporation loss. The additional low cost of
maintaining a clean white surface on a tank frequently
has an attractive economic return. Recent data indicate
that painting the tank roof and shell white, rather than
-------
-------------
- - ---- --~- --
FV,'\PORATION LOSs--CAUSF.S AND CONTROL
16
gray, rc:dul:es the evaporation-loss ratc by at least
20 per cent.
Use of Insulation: Insulation on the roof and shell
of a storage tank tends to reduce heat input and heat
loss; this tendency toward constant temperature reduces
breathing loss. However, when stock at higher than
normal storage temperature is added to an insulated
tank, the average tank temperature increases, which in
turn increases true vapor pressure and promotes a
higher concentration of hydrocarbons in the vapor
space. This condition may increase filling Joss some-
what and breathing 105s to a lesser degree. Insulation
usuaJly is expensive to install and may involve con-
siderable maintenance. Unless moisture is prevented
from entering the insulation, loss of insulation effect as
well as corro:,ion of the tank shell may rcsuJt.
Us(> of Shade: Shading of ;! ~torage tank from direct
sunlight reJuces heat input. but generally does not re-
duce normal heal, loss. Hl.'nce. cOlllp:\fed to a bare
tank, shading provHks /e:ss variation in internal tem-
perature and, usually. results in a lower :waage stock
temperature. Although the installation of shades gen-
erally has not been considcred economical, usually the
maintenance is not an expensi ve factor.
Use of Flexible Blanket Ofl Liquid Surface: Evapora-
tion lo~s in fixed-roof tanks can he reduced with the use
of flexible blankets which tlo"t directly on the liquid
surface. The blanket :lcts in the samt: manner as a
floating roof. Thele arc two types of tlexiblc blankets:
one is a foam blanket made lip of plastil: spheres; the
othe! is a blanket or raft made from plastic sheeting.
The latter type has nut been tested extensively in this
country.
The floating plastic-[u,\111 blanket consist~: of micro-
scopically small, hollow, plastic, gas-filled spheres. This
material has been used extensively on fixed-roof storage
tanks in nude-oil :,nvi,.'e. Tcst.s made in this country
and Canad;\ hJ\'e indIcated that under f.lv(Hahle con-
dition; cv;'porati,)1! loss un crude oil Cin he reduced
trom SO p..'[ cent to 70 per cent in WOI king tanks and
from 70 per cent to
-------
EVAPORATION-Loss CONTROL
17
--------- ---- ..---
-..-- --"
---
-.--- --
-_._-
------ -
C()lIrtc~y: Gencral A'ilcrican Tran~portation Corp.
FI(;. I-Pan-Typc, Houlill/!: Roor.
'-"
CO\lrlC\Y: ('I\ll'a~o 1I11.lg,' ;,nd II on ('omp;IIIY.
1'1(;. 2-I'''"lool.Ty IIc, FI"ulilljC !Coor.
-------
18
EVAPORATION LOSS-CAUSES AND ('Ot'oTROL
~
-,.'" ,
-'t'
'~.
- - ---
COlli fC,)' ,
lank ;JI:,1 IvLlnur;,,'llifllIg ('ompany, Inc.
FIG. :{--Ponloon.Typc Flooling Roof.
G ra vcr
th~ spa~:1,; betw~cn th,' lW,) dc~'h intl) C!HlIpartments;
thi~ design can givc good ~L'/1iiity .\I1d load-carrying
capacity and provides an insulating :Iir ~p~Il'l: over th~
entire area. Boiling !ossco llsually wili not occur with
stocks in the motor-I:'.Jsollll~ range l)f mlatillty,
The usual ~~al 10 a t1udting-roof tank consists of a
re1atively thin--gage shol' or sealing ring ~upportcd
against the tank ~he1l aroulid tht: edge of the floating
roof. The bottom ()[ the ~caling ring is helow the liquid
surface, and the top is a few incbe:, aboVl' till' top rim
of the roof. A piece of l1arne-retMdant rubherized cloth
closes the space between the sealing flng and the roof.
Another type of seal comists of a tlexibJe tube, fa~tened
to the roof and oc<:upying the :mnular space bctween
the (Oaf and shell. The tube, tilled with a nonfreezing
liquid, is held on the liquid surfal.:e and completely
climinJtcs the vJpor spacc. In ttnks with riveted ~hells,
abnormally high losses of the more volatile stocks oc-
cur necause the rivet heads and overlapping steel plates
hold the sealing ring away from the tank shell. Thus,
it is advbable to use a secondary st:al on rivcted tanks.
This type of seal consists of a strip or loop of lubber
adapted to cover the siot at the top of the scaling
ring. The valuc of a secondary seal for welded tanks
IS uncertain.
MJintl'I/(JI/('(' (If Tunk" Efficient and safe operatllJn
of any Hll'chanil;,tI devin,' which moves intermittently
requires Inspection and mallltenancc at regular inter-
vals; the floating-roof tank IS no exception, Shoes must
--
lil well, seals must be in good condition, the roof sh,,'d',.
he level at all timcs, and the breather valve and hit-I,d,,]'
vent must operate satisfactorily.
Bcfoie the tank is put into servicc the openiuiC !,(-
tween tank shdl and ,hoc should be minimized 1,\ ;i;
jllsting shoe spnngs or hanger s. If the litjuid ~1111.i\ I
is plainly visible between shoes and shell, after ,ill ;Ili.
justlllcnts arc made, the tank may he out-ot-hJlm.!
caused hy faulty construction 01 unevcn settling Be
l;au~c this conditHIO lead, to Lr'l:',e lo'-.'-.c, It ,hn:lid ~'\
corrected. Shoe til should he dH.:dcd I'l"'Otlil ,ill,
tile salllc tilllC, the dhovt:-dl't:k h:lngers sillHild 1\,
iced to keep them in an opcratlll~ condilJ' 'I
The primary and secontbry ,eal, ,hi)uld I" 'II, ,'u:
periodically for tightness and gcnl'lal ~'\llIdJII< Ii, ..:"c-
tions of the primary seal wilich !I;lve dt:IL'IH,J,II(,! and
have weakened should he It.:pLILt.:d Holes t!i"l :1;)pe,H
in sections of good matl'l i;lllI)a~ he rep;liICd by patch-
ing. The secomLli y scab arc ~ubject to considerable
abrasive wear and arc not ;llIll':lable to patching, such
worn-out seab should be rL'f)hced.
The floating pmition (the level) of a roof depends
upon the weight of the load supported and how easily
the roof can move lip and down. With riveted tanks,
shoes occasionally bear unevenly on the shell of the
tank. Inspection fOI this condition should be made peri-
odically and ~hoes adjusted as necessary. After every
1'.lIn, drainage from the roof should be checked an
any dehris clogging the screened roof drains should ht',-
-------
--------- _n_~-
--~- --- - -------- ---~~~-----~-~--- -------
EVAPORATION-Loss CONTROL
- ---- --- -------
19
- - - ---- - --- --
---- ---..-.-
---
Courtesy; Hammond I ron Works.
- -- -- - --
----
-------.-.- -
FIG. 4--Double-Dcck Houling Roof.
removed. Allhough a snow load is not serious for the
ponloon or double-deck roofs it can be with the pan-
Iype IOUf. When more than a foot or snow accum u-
laIc, on a roof of any type, it should be removed, par-
liL'liI:lrly if it drifts unevenly.
f)CSi/ifl of A C('('.\'.\'On' Fqllipment: Two accessories
are nece~sary 10 the operation of a HO:lting-roof tank:
a breather valve fOi the rim space and a bleeder vent for
the roof. One breather valve, sometimes t\,.o, is pro-
vided :It the outer edgejs of all types of floating-roof
tanks: it is similar in design to that used on fixed-roof
lanks, The hleeder vent for the pontoon and doub1c-
deck tanks allow~ air trapped under the roof to escape
before the mnf Iloats and prevents a vacuum as the
roof L'omcs to rest on its supports.
!\1uin!cl/ul1(" 01 ..I('('/',\'sory Fqllif'tllcl/!: The fol-
lowing aCCe',',(lIIC, ~il(llild he inspected regularly and
repaired ,I, rll'Ll'~".IIV hleather valve~ (rim vents),
bleeder vent'" ','l1lj)k ,IPt! g
-------
20
E\',\ i'i II<.Anm, LO~)S---CAUSL" AND CONTROL
when the g;l\lhJlliLr l';tp:Jcity I:; \';'.c'u:dcd, Iii ronling,
the vapors from tl1l' ga:;IJOldcr ;11(' drawn b;\ck tnt.o the
tank. Vuriahle-v,'plH'~pan: l';lP;\Clty usually I~ \UIlILll'nt
50 that one ga\ltnldl'1 dl'\'ll'C Iday In; I'sed ill c"njullc"
tion \\ Jth onc <11 1Ij()1 C inlci cOl1J1ecLl:d I1xed-roof tanks
opcratin~ ;It \Uh\t:lIltl:tlly the samt.: pressure. Fillmg loss
,\ not tn.ltcllally reduced, except in a can:ful1y con-
trolled oreliltiur1 However, because of the effectivencss
in rcducmg breathing loss, this tank has been widely
;Il'ceptcd, panicularly where tank throughput is i,1W.
[){'sign of TUIl!,: '1 he first \'
-------
21
EVAPORATION-Loss CONTROL
----_.._---------~---- -
------ ------
I
'--
,i ,r
/J
/<~
/
( till I II..." ~ .
11.111'1"" 1;11 j"l1 \ '",!, ,
( It III..' I;'} . \ Illl' III. ,III
FII;, II -Hr' .,""...1 I.ifl.", I\....f.
SIIICS L'(111111)1 thc 0I'CI:ttlllt! PIC\SlIIl' If) the enlire sys-
kill, IIltCILOl1l1l'L'll'd Ilscd'!I'(lf Lmks 11111,1 he designed
.111\1 LOII'lllldcd tn \\'llh'1.llld this opcr:\ting prcss"tlle
pili, till' I'll'S',IIIC dlol' ill thl' IntercOTlIll'ctini! vapor
'V\tCII! 1,IIIs :1 Il'Sl'1 Vl' [0 kL'l'p the V\:lIt fl1'm leaking,
Ill,: Jkxihlc.dl'Ij'!11 ,1\111 1,IIIk, inlmdllccd jllst heforc
\\'",Id \',1:11 II, ,"I\l'" till' ',IIl1l' p1111'0SC :I'. the liftcr-
luul LillI.. hy 1'1 ()vld'Il.", l'\I',lIlSinll l'al'.IClly through the
1110\'1'111Cnt (If till' dl.q)hr.I!~ll1 The 110.rble-diaphragm
tanks have an advantage over the lifter-roof tanks in
that the operating pressure is relatively low; therefore,
it is seldom necessary to strengthen the interconnected
fixed-roof tanks. Also, the lower pressure reduces the
magnitude of any leaks which may develop.
There are two types of flexible-diaphragm tanks:
the integral unit and the separate unit. A type of in-
tegral unit is shown in Fig. 7. This tank is essentially
a fixed-roof tank with a steel shell located on the roof;
a flexible diaphragm attached to the inside of the shell
can expand or contract as the confined vapors change
in volume, A type of separate unit is shown in Fig. 8.
This gasholder is an upright cylindrical unit with a flex-
ible diaphragm attached to the horizontal center. It
may he connected to one or more fixed-roof tanks.
The diaphragm mat-.:rial used in dry-seal lifter roofs,
tl\:xihle-diaphragm tanks, and dry-seal gash alders must
h:lve:
I. High strength.
2, Good chemical resistance to product and vapors in
contact with it.
3, High flexibility over a wide rang\: of temperatures.
4. Good aging properties.
5. A high degree of imp\:rmeability to vapors and to
the liqUid product itself when there i~ contact.
Thc mtcrconnecting vapor lines should be of ade-
Ljuate di:lmeter for mll1imum pressure drop, V:1!'or
lines should be sloped to one or mOl'\: low point'; with
dr:lills at each point for drawing oft acculllul,dul con-
dClls;ltion. When aviation alld motll! g.I,(']inc, are
,torct! ill the same systcm, it may hc dC'll'ahk to Install
"
\ 1I11I.'c'\; )1..1111111111<1 Irol1 Worl..s.
.....;. ;.-FIf'xihl(.-DiaphraKI11 Ta"k (I "I../:ral U"il).
-------
--~- ---- ---
EVAPORATION LOss--CAUSES AND CONTROL
22
;.~\" . " 'y/
.'-' ~:.._... ..'.' '
. ,..
-~--
( ""III~'y
(;, ,1\ ,'I l'..nf, and J\lal1l1faclllring ('nmpany, Inc.
1-'1(;. H-- .1-'1.."ihl,'.B;""hrnIt01 Tnnk (S",lIIrnh' I ]"it).
check v,dws in the vapor lines from the
-------
23
Ev APORA TION-Loss CONTROL
D. Pressure Tanke
Pressure tanks are conservatioo devices which can
withstand relatively large pressure variations without
incurrin~ a, loss. Some tanks withstand only the pres-
sure vanatlons caused by daily temperature changes,
whereas others prevent boiling of volatile stocks-
stock~ as vol.atile as propane. Therefore, pressure tanks
expenence little or no breathing losses. Filling losses
may vary widely, depending upon product character-
istics, vent-valve setting, and fill-pipe arrangement. Fill
pipes arranged for filling into the vapor space (some-
times calle~ ~pray filli,ng) will greatly decrease and fre-
quently ehmmate filhng lo::,s on tanks which do not
inbreathe,
Design of Tank: An early adaptation of the principle
of pr('~sure storag~ w~s the water-top roof; a 6-in. layer
of w: II r wa~ mamtamed on the roof as a restraining
f?rcL to the mternal pressure. Later, with the applica-
tion of pressure-vessel design principles, the modem
pressure tanks were developed. Today, there are two
classes of i'~essure tanks in g~lleral use: low-pressure
tanks operatmg betwee.n 2.5 pSlg and 15 psig and high-
pressure tanks operating up to 250 psig or higher.
Lo~-pr~ssure tanks can tolerate only a slight vacuum,
ordmanly only 1 oz to 2 oz per sq in. but high-pressure
tanks can be designed to withstand full vacuum.
Lo~-pressure ~anks are constructed in many shapes
and sizes dependu~g u~on the operating-pressure range.
The tank. shown m. Fig. ,9 .operates between 2.5 psig
and 5 pSlg, Essentially, It IS a fixed-roof tank with a
flat hottom and dome roof. This tank is reinforced by
.~.
-/~- ,/
.~ /
,,=- -----
. _.
-------
--,
('OUrloy: IllImmund lion Works.
FIG. 9-Low.Pr.'..ur.' Tallk.
-------
means of a ring girder at the intersection of the shell
and dome roof and diagonal ties between the tank bot-
tom and the tank shell.
Ano.ther style of low-pressure tank, the noded hemi-
spherOid, is shown in Fig. 10. This tank is designed
for a pressure range of 2.5 psig to 5 psig. It consists
of a cylindrical shell with curved plates in the top and
bottom which may be either smooth or noded. In the
plai~ hemispheroid there arc ring girders at the inter-
sectIOn of the roof and shell, and the shell and the
bottom, to withstand compression at these points when
the vessel is subjected to internal pressure.
The ?oded spheroid tank, illustrated in Fig. II, has
been wldel~ accepted for o.p,erating pressures ranging
up to 15 pSlg; storage capacities range from 40,000 bbl
to 120,000 bbl. These tanks have curved shells with
internal ties and trusses and one or more nodes in the
roof and boHom. Besides a ring girder and brackets
around the external base of the shell, internal trusses
support the curved portion of the shell and nodes in
the roof. Also, a center column serves as a roof sup-
port.
The spheroid, as illustrated in Fig. 12, is available
for st~rage capacities ranging up to 40,000 bbl and
ope rat 109 p:essures ranging up to 30 psig. Spheroids
are smo~th 10 appearance ~nd have !!O internal framing.
Th~ hlgh-pre~sure tank IS a vessel, either cylindrical,
sphen<:a1, or blimp-shaped, designed for working pres-
sures 10 excess of 30 psig. The maximum allowable
wor~ing pressure is now limited by tank size and code
requuements. For a 1,000-bbl sphere the maximum
pressure is approximately 215 psig; for a 30,OOO-bbl
20.000-BARREL CAPACITY
2Y.J LBS. PER SQ. IN.
PRESSURE
60 FT. 4 IN.
DIAMETER
HIGH LIQUID LEVEL
t:
i
IllY AnON
SICTION
Courtesy: Chicago Bridllc lInd Iron Compllny,
FIG. lO-Nodc.1 lIt"mllpherold.
-------
-- --- ---_.----~-_.__. - ---~-----
EVAPORATION LoSS--CAUSES AND \mITRL',--,
24
IO,OOO.BARRfL C"PACITY
._-------------_._~-
10 ll\ ~I' \(') IN ""h"1
III If ... IN r'I"''''UIA
IUVAflON
SleTlON
\A,...1I CU!.IUON
Courte~y: Chil::lgo Bridge and Iron Company.
"'J(~. II--Nodcd Sph,'rui.l.
sphere, it IS appluximalely 50 p~lg. Thc~e pressure
limits can be il1l.:1 c<1,'~ed if the vessel is stress relieved
A typical high-pressure s;)h~re is ~hown in Fig. J 3.
Dt'sign of Accessory Fill/ifill/flit: Special !!astight
accessories arc required because of the high-plcssl1I'c
operations. The pressure-vacuum relief vent, and either
a pressure lock or an aut()l11atic jJoat gage arc nrcded
for normal opcr:. be in'l) <:leJ ffe~Jl1CI1t1y '0 insule
th;tl i'!Ilkl",1 ,;(,;c')s(!ric~; :He in gastight condition.
Rup1UI'2 ,d.'iilll.:; q\e pilol or main diaphragm of a
pilot'OPfl;Jkd [('I~cf valve wil1 CHJse the va1w: to open 3t
a !ACSsllr,. :",:lInv ~IJC;Cl prc:.sme. V,livc performance
should he ,11'cud Ir"'rlodi,'ally. Diaphragms shuuld be
IrtS!Wc(l'(: :. 'I ''-1 ''';,d!l1,'.'il Oi.lle'l :,ie:ns of deterioration
;lnd ll'pl,IL"I.": :1:: OCH',:s:lry Slilllypl' brc:\thcr valvc~;
!,IJuliid i,,-, 1,:'::,P':I.,,',:d ill')I,: Ire(]IJt:r,lly to deled and
CUll,> I 1,('( /ilij2, :\nd :;'i..king pI' palll.:ls.
1<1;\111(' .InC.':!',)I,', should I\l' Iw;pedl.:d and \'Ieancd
1'C1lulilc.dly 10 pn:v'_~i1i d()~'.i.,llIg willi dirt or ice.
("}}II/"(' ,.0.1 ,r', II/If: To 11111111111:1.\.' pi"l'SSIW,~ vanations
wllhill jhc I:ll"Ii'.s, !hey slu)ldd \", e;linlcd with a heat-
Idklliw i"'AIII, Although P:1illl color is nol. as critic:i\
as on f!",.'d-:,',>ur and v;lriahJc-vapm.space tanks, white
paint is 1.111"1llWJPIY used
-------
------ -_._---~-~
EVAPORATION-Loss CONTROL
25
E. Vapor-Recovery SY8tem8
Design of System: Yapor-recovery systems collect
vapor from storage tanks and send it to a gas-recovery
plant. These systems have sensitive pressure-vacuum
controls and remove vapor as pressures build up dur-
ing pumping into the tanks or during breathing. The
vapor is collected, compressed, and then recovered by
absorption or condensation; with lease tanks, how-
ever, the compressed gas normally is discharged into
an extraction-plant gathering system. A properly de-
signed system should climinate most of the evaporation
loss, but because of control difficulties the efficiency
actually is somewhat lower.
Refinery or natural gas is sometimes used for re-
pressuring the vapor spaces of tanks when air or a
corw~ive atmosphere is undesirable in the vapor-re-
COVfr) ~ystem. The vapors are withdrawn from the
tan as the internal pressure increases, and the repres-
suring gas is admitted to the tank when air normally
would be drawn in. Some provision must be made to
prevent collapse of the tanks when insufficient gas
evolves to maintain pressure in the tanks.
Where it is uneconomical to design a tank or a stor-
age system to operate at pressures high enough to
make evaporation loss negligible, various vapor-re-
covery methods can be utilized. To recover vapor by
condensation, one or a combination of four methods
may he used:
1. Ahsorption may he accomplished in a suitable liquid
of higher molecular weight than that of the vapors be-
ing recovered. This rich oil must be reproce~;sed if it
is desired to separate the absorbed vapors. The liquid
from which the vapors originally escaped also can be
used as the absorption medium and then the enriched
liquid can be returned to the storage tank without
further processing. Vapor usually is absorbed under
pressure.
2. Compression of the vapors, under suitable tem-
peratme conditions, will condense part or all of the
vapors.
3. Cooling, alone or in combination with compression,
can return v
-------
CHAPTER 4-PROCEDURES I..-.OR CONTROLLING EVAPORATION LOSS
IN OPERATIONS
Many of the operations carricd Ollt in production,
refining, transportation, and marketing are potential
sources of loss. Therefore, procedures which minimize
evaporat10ll loss arc desirable. In production, contlOl
of temperature and pressure in the gas-oil separators
and in emulsion-treating equipment is important. In
refining, the operation of treating plants, anJ scwers,
ponds, and open separators require special considera-
tions. In transportation, the methods for loading and
unloading of vessels arc all-important. Marketing prob-
lems essentially an: similar to those experienced in
transportation.
A. Pro,Juction of C!"Iull' Oil
I n the product ion of crud!; oil, the mCihods :md con-
ditions employed in the gas-oil separation and the
emulsion-treating steps will influence evaporation loss.
Comet vatiol1 measures should he lonsidercd for these
steps to minimize loss from subsequent operations.
G<1.f-Oil Separation: Newly produced crude oil flows
from the well to a separator through an cll1ulsion-treat-
ing plant, and then to a kase tank. In a gas-oil sepa-
rator, the hyolUc;lI bon~, ;,re divided into a gas (natural)
and a liquid (crude 011 ;mc..l/or condensate) at the exist-
ing pressure and Icmp!;raturc. The phase hehavior of
the spccific gas-oil J1lixtllfl~ ~(\verns the distribution of
the intcrmedl;lte Clill1l'0nents so that any given COJ1l-
ponent, such as butane, becomes distributco as a part
of the gas and of the oil. In all emulsion-treating proc-
esses, the oil-gas-water mixtures go through one or
more additional g~ls-ojl ser,lI "tions. When the 1iquid
enters the lease t;ln k, .II1Ot lief g:1S-()J I separa tion OCClll'S,
normally, :It a difTcrent pressure and temper;Iture.
Again. the hyorocarhons distribute thelmclves into a
gas and a liquid phas!;. In thl:sC separations, SOI11!; of
the "crude oil COlllp()fICnh" Icrn:lill with the I~a'; ;tlld
some of the g;I:, ITlll:lillS, ;\t lea.\t 1'('1 ,I liIIIL', ill solution
with the crude .)il. I kn'..T, thcsc g:tS--oi! ~Cp:ILltlons ;trl:
highly il11port:lI1t fruil1 thc ~Iandp(\int of p(\\sihk hydro-
carbon 10ss(~';, and particul:nly wilh respccl tl' possible
subsequent (,II I\!sscs after the uil \caves the producer's
tan ks.
T'Ih: quantil:' of 1Il1'Idiable \':11'0rs in the g.ls l';10 be
contIOlied in two ways. One method is to contlo! the
prcs'lHl' and, where proictiL';II, the IL'lI1reLltLJre of scpa-
ratilH1. This will deliver the 1I1:1ximllm amollnt of these
constitul:nls (() the Ic
-------
27
- ----- -
Bv APORA nON-Loss PROCEDURES
-----------~--------- -..
----
Heat In tho outgoing treated crude oil can be mini-
mized by cooling in heat exchange with the incoming
stream. In some cases, reduced loss can justify the use
of cooling coils in the stock tanks.
Treater pressure can be controlled within limits to
reduce loss. There is an optimum operating pressure
for each crude oil, which results in the release of the
greatest amount of volatile constituents with a minimum
release of the intermediate constituents.
This discussion of emulsion treating has dealt with
means of delivering a maximum quantity of crude oil to
the lease tanks. For lease operations at normal tem-
peratures, when there is a vapor-recovery plant in the
field, this may not be the most desirable procedure. A
treater on the ~ease may be operated to deliver a por-
tion of the volatile components to the recovery plant
and, thus, reduce the compressor load for recovery of
w.Jk vapors.
rlandling very viscous crude oils requires heat to
reduce viscosity so the crude oil can be pumped eco-
nomically. This situation occurs infrequently but should
be discussed briefly. At the higher temperatures, these
crude oils will have a greater tendency to evaporate,
therefore they should be given special consideration.
In applying heat, take care to avoid localized boiling.
Even though the bulk of the oil is below its boiling
point, local overheating can lead to a large loss.
The temperature of the oil should be kept as low as
possible, consistent with the viscosity requirements. This
involves an economic balance between the increased
vapor loss which will result from the higher tempera-
ture operation, the value of these vapors as used or
recovered, the cost of remedial measures to retard
evaporation, and the savings in reduced pumping cost
as a result of the lower viscosities attained at higher oil
temperatures.
B. Refining
In refining, the pressure systems, treating and blend-
ing operations, and sewers, ponds, and open separators
must be operated with care to minimize evaporation
loss.
Prc.\'Jure Systt'f1l.1': Some loss reduction can be
achieved by maintaining pressure systems in a gas tight
condition. In addition, proper attention should be
given to exchangers, glands, valves, and fittings to
insure that they do not leak.
Treating and ~/ending: The major factor affecting
loss from treating and blending operations is the degree
of opportunity for a gas to enter the system, become
saturated (partially or completely) with hydrocarbon,
and leave the system. Air and other gases come into
contact with hydrocarbons in treating processes in
various ways. The resultant vapor issuing from the
process may contain hydrocarbons in practically any
degree of saturation, depending upon the intimacy and
length of time in contact. Therefore, use of excessive
air for treating and blending operations should be
avoided. If possible, such processing vessels should be
made a part of a closed system.
Sewers, Ponds, and Open Separators: Positive steps
should be taken to prevent volatile liquids from reach-
ing sewers, ponds, or open separators. This operation
is best performed by isolating the individual sources of
hydrocarbon entry into the sewer system. The possi-
bility of segregating any source that contains volatile
constituents should be considered.
C. Transportation and Marketing
Reduction of loss in the transportation of crude oil
and its products can be achieved by the manner in
which the carrier is loaded and unloaded. Control of
loss also can be accomplished during the transit period
between ports.
Loading Cargo Vessels, Tank Cars, and Tank Trucks:
The filling lines of an oil tanker form a permanent part
of its cargo piping system. The discharge nozzles are
placed close to the compartment bottom and positioned
to permit the flow of oil to be parallel with the bottom
of the oil tanker. This arrangement minimizes the ex-
tent and duration of disturbance on the oil surface,
consequently minimizing the loading evaporation loss.
Tank cars and tank trucks are either subsurface
loaded or splash loaded. The latter method should be
avoided because it leads to excessive loss.
For effective subsurface loading, the outlet for the
loading line should be extended to the bottom of the
container in order to discharge the product below the
surface of the liquid soon after me start of the opera-
tion. As a result, spray loss is almost eliminated. The
loading pipe for subsurface loading of tank cars is a
detachable aluminum or brass spout which extends to
the bottom of the car; it is connected to tbe Ioading-
line outlet by a quarter-turn quick coupling. This con-
nection should be kept gastight to eliminate drawing in
air. The subsequent escape of such air will increase
the evaporation loss appreciably.
For subsurface loading of tank trucks, the long down-
spout usually is part of a swinging counterweighted-
loading-arm assembly. Tbis system provides adequate
flexibility for horizontal and vertical movements. To
achieve optimum efficiency, the outlet should be kept
as close as possible to the bottom of the compartment.
InstaUations for the recovery of vapors from loading
operations have several forms, such as:
1. A system of special hoods, collecting pipelines, and
a compressor to gather and deliver to a fuel system any
vapor issuing from the truck hatches.
2. A system as described in item 1 but for delivery of
the vapors into an existing absorption system, such as
in a refinery, or into a specially built absorption unit
using gasoline as the absorbing medium.
3. Recovery of the vapors by returning them to the
vapor spaces in the storage tanks from which the liquid
originated.
-------
28
EVAIi'ORA TJOi'< LOSS----('Atl,-t:~,: AND CONTROL
-.--- - ----------
- ~ - .-----.-----.--
.---.- -
Cargo Vessf'ls in Trarui!: hHransit evaporation Joss
can be reduced by several means. Surge and agi.tation
with its ensuing 105s can he reduced by thc use of hulk..
heads ,lOll baffle plates. Loss 1)('cilUSC of heat absorp-.
tion can be reduced by tbe use of imll~a~i()rn 01" renec-
tive paints. but with product.s of low voia~i!ily ih(;~~c
means usually arc impractical or uneconomical. Loss
caused by the escape of vapor during tr;1nSI~ ,~an be
reduced by the lIse of presSlIre-VllCmlrn vent valvC's,
which is norma] operation for OCC2LrJ !"n ker and b:ugc
transportation.
U nloadmfi Carfio Vessels, T ani: Cors, .rIwi Tonk
Trucks: Du!inh the cargo discharge from oii rankers,
evapor:ltion of the product c usually no problem riS the discharge raIl's
are low. However, in a1l unloading operations care
~houlJ he ta ken to 3\ oid drawing vapor into the pump.
Pipelines: A deacas<.: in evaporation }OS\ can be ob-
tained by reducing the number of L.nks used in ripe-
line oper<1t!\mS rmd hy reducing the frequency with
which ~tocks are pumped into unci out of t;1!lks. A
means to this end 1$ to use a closed pip~line syo,tern with
positive-displacement meters for measuring receipts Jnd
deliveries.
Controlled pUlI1pings ffc)n1 kase.-unk hd1!crics into
a gathering l,yqCI:' -:an affect loss. Such h;\W'fies sl10lJld
be equipped with tank shutofT valves au,! p\il1:ps with
speed-reducing uevlccs to decrease the IJlII11I1IO); rate and
prevent air from heif1g drawn injo the gathering sy:;-
tern. Special care should b..: Liken with lease pumps
operated by lJlJlt: docks to avoid having ,) pipehnc
pump opnate and dr.1W air into the gathering system
._.-~--_._,.~ .
--- --------- --.
aft!'T ;::vai1ab!e oil has been moved from the lease tank.
H is common practice to occasionally mix sma1l per-
centages of butane or high-vapor-pressure natural gaso-
lines with crude oils. These components should be
added wliformly and in such a way that the specified
t'ercemagt- of butane or natural gasoline will not be
cx.ce-eJcd. H i" preferable to mix such components in
the pipeline system while bypassing storage tanks as
much as possible. Mixing should be done under suf.
ficiCl!l prv,sure [0 avoid vaporization of the more
v(J'ia'iik component.
Tae use of mechanical seals on pumps, cathodic pro-
tenion of pipelines, and better housekeeping wilt help
to rcduce Joss.
li..farkeling: Evaporation-Joss problems in marketing
an: similar to those encountered in storage of products
ami .ik1 transportation.
lb'. IC1.mdUII'5io'l1l
Control of evaporation loss requires constant atten-
tion. Oil companies and tank manufacturers are con-
:::tantiy devcloping new devices and improving existing
ones. Conservation equipment may become less effec-
tive "~Iith ;,gc, and an cvaluation frequently reveals that
,n(,,!crniza1ioH would he more economical. As prod.
uct lines shirt and product qualities change, reshuf.
fting 01 tank services may reduce overall Joss. Con.
tinued "ttention is required to maintain repair schedules
(Jul.! to keep ctesirable operating procedures in effect.
Such factors demonstrate the need for organized pro-
grams for Joss control.
Some type of centralized responsibility for loss coo-
tro1 tJsuaHy works best. In some situations, the control
program may be only a part-time job for an engincer.
In other instances, the engineer may be responsible for
los5 cantroll in a specific division of the company. Some
large companies have loss-control departments with
broaJ n::sponsibiJitlcs to insure the best handling of loss
~"oblcn IS ai alilacations. Regardless of the admmistra-
tive :.Jppro~lch, some one, or some group, should be
rn;ide I cspol1c.iblc for controlling evaporation loss at
each source. This will provide the necessary concerted
aUcnti0n that must be given to this important, economic
subjcu rebted to the conservation of petroleum and its
pl"Oducts.
-------
APPENDIX I-DEFINITIONS AND SIGNIFICANCE OF FUNDAMENTAL TERMS
This section defines terms connected with evapora-
tion-loss principles which govern the rate of loss.
A. Vapor Pre88ure of a Liquid
Vapor pressure is a measure of the force that tends
to vaporize any volatile liquid, sitch as petroleum.
Molecular motion within the liquiu is responsible for
this force and is related to the composition of the
liquid. Smaller molecdes arc more active; thus, vapor
pressure increases as the proportion of these low-boiling
(smaller molecule) components increases. Higher
temperatures also stimulate molecular motion and
lli!her vapor pressure.
In evaporation-loss work, petroleum frequently is in
contact with a vapor space. The molecules which
vaporize tend to disperse throughout the vapor space.
At the same time, some of the molecules in the vapor
space return to the liquid. Equilibrium is established
when molecules leave and return to the liquid at the
~iame rate. At any given storage pressure, the equi-
lihrium percentage of hydrocarbon vapor in the vapor
space, essentially, is directly proportional to the vapor
pressure of the liquid.
n. True Vapor Pre!lsure of a Licluid
True v,lpor pn:ssure is the v,'por pressure of a litjuid
at a spl'citicd temperi\ture and without it~. composition
heing changed by vaporization which occurs in most
procedures med to measure vapor pi essure. With
mixtures. stich vaporization results in a lowering of the
measured vapor pressure. Trtlc vapor pressure differen-
tiates from vapor pressures so determined.
Vaporization from a hydrocarbon mixture lowers the
vapor pre~<;ure hecause the lighter components vaporize
more readily, leaving the liquid richer in the heavier,
less-vohtik: cc )IlIponents. Tilus, for motor gasolines and
similar wide-hoiling mixtures, the true vapor pressure
at 1 no F molY he significantly higher than the Reid
vapor prl'ssure (R VP), because some vaporization is
encountel cd during the Reid test. For a pure ~;ipgle
(Ol11pOIIl'nt. liquid vaporiz:'tion will not change the
vapor rrl'~\llIl' and true v;lpor pressllre suhstantially
will eqllod t 11l' I{ V P
Trill' \'.Ipor pressure can he e\tilllall'd from conda-
tiolls rebtln~' il to [{VI' and ASTM hoiling characteris-
tics. (,h;1I fe; in Appendix V illustrate such relationships
for gasolille~ ;,,,d crude oils over a wide range of tcm-
peratures. AllllOUgll there i~ no stand,lrdizcd procedure
for directly dl'tcrlllll1mg true vapor pressure, a research
approach involves the testing of a gas and air-free sam-
ple in a container with an infinitesimally small vapor
space. The charts in Appendix V, for gasolines, arc
based on true vapor pressure measurements maul' by
this research method.
In evaporation-loss work, true vapor pressure at
storage temperatures directly affects the rate of evapora-
tion loss. Increased true vapor pressure accelerates the
rate of evaporation into any tank vapor space. Also, at
saturation a vapor space contains proportionately more
hydrocarbon vapors as true vapor pressure rises. Both
of these factors increase the evaporation loss from the
tank during any specific breathing cycle or filling
schedule.
C. Reid Vapor Prcssure of a Liquid
Reid vapor pressure (RVP) is the absolute pressure
in pounds per square ineh determined at 100 F and
~ = 4 (ratio of vapor volume to liquid volume, as
defined in ASTM Designation: D 323-56) by using
apparatus and procedures as standardized under the
auspices of the American Society for Testing Materials.
Thus. the RVP is the vapor pressure of a sample which
has had its composition changed because of the vapori-
zation required to saturate the vapor space of the bomb.
Accordingly, R VP is slightly lower than the true vapor
pressure of the sample at 100 F.
Frequently, RVP is used to characterize volatility
of gasolines and crude oils; it also provides the most
convenient method for evaluation of true vapor pres-
sure. Through correlation, RVP of the hydrocarbon
liquid under investigation can be converted to true
vapor pressure at any normal storage temperature.
Charts in Appendix V relate R VP and ASTM boiling
characteristics of gasolines and erode oils to true vapor
pressure over a wide range of temperatures.
D. Partial Pre8sure of Vapor
The partial pressure of hydrocarbon vapor in a
vapor space is a measure of the force exerted by hydro-
carbon molecules striking the confining wall. Air mole-
cules, usually present in evaporation-loss problems,
similarly generate a partial pressure. The sum of all
partial pressures equals the tot;!1 pressure of the system;
the partial pressure of any vapor component is propor-
tional to its volumetric fraction of the vapor space.
In evapor;ition-Ioss work, a vapor space normally is
in contact with Ihe lilJuid which emits the hydrocarbon
vapors. An equilihriulll exists when the partial pressure
of hydrocarbon vapor equals the vapor pressure of the
liquid and the rates of vaporization and condensation
arc equal.
E. Saturation of a Vapor Space
The vapor space in a tank, with respect to a given
component, is said to be saturated when equilibrium
exists between that component in the vapor and the
29
-------
30
EVAPORATiON LOSS--CAUSES AND CONTROL
.. -_.~--,._---------- ---- ---- - .---------
--- --.
liquid phases under given conditions of tempe.-ature and
pressure, and the composition of the vapor space is
uniform throughout.
Degree of saturation is the percentage of saturation
with respect to a given component which prevails at
any given time or location under normal equilibrium
conditions.
1<'. Diffullion in 11 V/lpOI!' Space
Diffusion is the molecular motion whidl Ilcnds to uni-
formly distribute any component throughout a vapor
space. The rate of ditfusion is highest for smaller
molecilies which travel hstest. Also, the ratc is pro-
portional to the distance a molc<.:ule travels before it
IS impeLed by collision with another molc<.:ulc. Thus,
the total time .0 reach equilibrium depends upon the
size of the molecules, the size of the vapor space, the
temperature, am.! pressure.
In evaporation-Joss work, diffusion is one way by
which newly vaporized hydrocarbons distribute them-
selves throughout a vapor space in an eflort to saturate
it. For gasoline components at norma1 storage and
operating temperatures, the diffusion process is rela-
tively slow and, by itself, exerts a minor influence 011
evaporation loss.
G. VaporizRlion
Vaporization is the process whereby a liquid changes
to a vapor, either wIth or without boiling.
H. Conden8ation
Condensation is the process of a vapor changing to
a liquid. It is the reverse of vaporization and occurs
when the partial prcssure of the vapor exceeds the vapor
pressure of the liquid became the liquid temperature
drops or vapor-space volume decreases. However, con-
densation also may m;cur when the vapor temperature
drops because of a decrease in ambient temperature.
In this case, the partial pressure of the vapor and liquid
droplets in the vapor space may be less than the vapor
pressure of the main liquid interface.
JI. Conduction
Conduction is the transfer of heat from one part of a
body to another part of the same body, or from one
body 10 another in physical contact with it; 00 ap-
preciable dbplacement of the particles of the body oc-
cure;. Heat coming from the outside passes through the
tank, wall by conduction.
J. Convection
Convection is the transfer of heat by the movement
and mixing of tIuids induced by temperature differences.
Hot gases and liquids with low density rising in a con-
tainer and cold gases and liquids with higher density
settling in a container represent the movement of ma-
terial by convection. In addition to the movement of
material caused by temperature differences (thermal
convection), movement may be induced by other means,
such as a pump or the wind. Heat may be transferred
to or from another tank surface by convection caused
by wind and is dependent upon the wind velocity. Heat
may be transferred to or from the inner tank sJJrface by
thermal coovectjon. In this process, heat is added to
OK' taken from the material in the tank.
K. R~uUiaQion
A hot body gives off heat in the form of radiant
energy. When this energy strikes another body, part is
reflected and the rest is absorbed and transfOimed into
heat. The rate at which a body absorbs radiant energy
as heat is dependent upon its area-surface reflective
properties, its geometrical exposure to the source, and
to the temperature difference between it and the source.
Heal may be transferred directly from the surroundings
to the outer tank surface by radiation. The direction of
heat tran:;fer, the rate, and the amount are, of course,
controlled by weather and time conditions.
-------
APPENDIX II-DERIVATION OF BREATHING- AND FILLING-LOSS EQUATIONS 18
A theoretical breathing-loss equation can be derived
from the ideal gas laws and from the pressure, tempera-
ture, and volume conditions in the vapor space of a
tank containing a volatile liquid. An equation for
filling losses can also he developed.
First, the laws governing the behavior of ideal gases
must be defined. For perfect gases, the relations be-
tween pressure, volume, and temperature are defined
by the law:
~abso!~p..!~~ure)~vol~me) = constant
(absolute temperature)
'1'1..:> equation, based on Boyle's and Charles' laws, is
Ilsed to analyze conditions in the vapor space of a tank.
A. Breathing L088e8
For example, a tank is partly fined with a volatile
liquid and equipped with a pressure-vacuum vent. In
the most general case, vapor-space volume, total pres-
sure, and temperature vary, but to different degrees.
The various pressure, volume, and temperature terms
used can be defined as:
P, = gage pressure at which tank vacuum vent
opens, pounds per square inch gage.
P 2 = gage pressure at which tank pressure vent
opens, pounds per square inch ga:;e.
p. = atmospheric pressure (standard condition of
14.7 psia).
P, = vapor pressure at minimum liquid-surface
temperature, pounds per square inch absolute.
P1 = vapor pressure at maximum liquid-surface
temperature, pounds per square inch absolute.
t, = minimum average vapor-space temperature,
degrees Fahrenheit.
t2::: maximum average vapor-space temperature,
degrees Fahrenheit.
V, = minimum volume of vapor space, cubic feet.
V.= maximum volume of vapor space, cubic feet.
Vn= volume of vapor lost by breathing, cubic feet.
1= per cent volume increase of vapor space.
G = gallons of gasoline lost in one breathing cycle.
During breathing, the temperature, volume, and
pressure vary from a certain combination of minimum
conditions to a ccrtain combination of maximum con-
ditions. All of the variables are assumed to be at mini-
mum conditions simultaneously, and to change and ar-
rive at maximum conditions simultaneously.
Consider the air 10 the vapor space of a closed con-
tainer partly flllcd with volatile liquids. At minimum
conditions, the volume of the air is V" and the tem-
perature is i J' Assuming that the vacuum vent is on the
. Figures refer to REFERENCES on p. 34.
verge of opening, the total absolute pressure in the
vapor space is Pa+P,. The vapor pressure P, in the
space is the vapor pressure of the stored volatile liquid
at its liquid-surface temperature. The partial pressure
of the air in the vapor is, therefore, Pa + P t - p J.
Likewise, at the maximum conditions, the volume of
the air is V., and the temperature is i.. Assuming that
the pressure-relief vent is on the verge of opening, the
total absolute pressure in the vapor space is P a + P ,.
The vapor pressure corresponding to the maximum
liquid-surface temperature is p.. Hence, the partial
pressure of the air is pa+p.-p..
Then, from the laws of perfect gases as applied to
the air only, the product of the partial pressure and
volume of the air, divided by the absolute temperature,
is constant, or:
(!"~!~~g') V.= (!,.t{~~~)V1 (I)
This is the general formula for the pressure-volume-
temperature relationship in the vapor space of a closed
system of storage of volatile liquids.
For a storage- and evaporation-saving system in-
volving a variable vapor-space volume, equation (1)
may be written:
V. = (P'+P'-P,)(t.::t~.~())
V, P.+P,-p. t,+460
And by definition of I:
. I = v,-y, = V'-I
100 V, V,
Hence:
1= 100 [(P'+P'-=-P1)(t'j-460) -I J
P.+P.-p. t,+460
This is the formula for the per cent of expansion re-
quired to prevent losses by breathing caused by tem-
perature variation.
However, if the size of the vapor space is constant,
the volume represented in this expansion is lost through
the tank vents. This is the case with a fixed-roof tank
at constant liquid level and not connected to a vapor-
conservation system. Then, because the constant vapor-
space volume equals the minimum vapor-space volume,
V t, the volume of vapor lost by breathing is:
y.. = V, [(P.+P'-P,)(I,+460) -IJ
P.+P.-P. t,+41)0
Knowing the number of cubic feet occupied by 1 gal of
liquid when it is in the form of a saturated vapor per-
mits conversion of this vapor volume into gallons of
liquid.
Avogadro's law, an important and useful concept,
logically leads to an understanding of the relation be-
(2)
(3 )
31
-------
32
EVAPORATION Loss--CAUSES AND CONTROL
tween molecular weight and vapor volume. This law
states:
All perfect gases at a given pressure and tempera-
ture have the same number of molecules in any
given volume.
Thus, the density of a perfect gas is proportional to the
molecular weight. Where M is the molecular weight,
a pound mol or M pounds of perfect gas will occupy
approximately 379.5 cu ft at 60 F and atmospheric pres-
sure. Like other gas laws, Avogadro's law is approxi-
mate for real gases and vapors. For hydrocarbon vapors,
M pounds will occupy approximately (379.5) (C)
cu ft at 60 F and 14.7 psia; C is the compressi-
bility fal:tor. C == ~~, and may differ from unity by
. several pcl . ~!lto and will vJrY ..vith the composition of
the vapor .lnd with the true vapor pressure of the liquid.
A vapor tu liquid conversion factor. number of cubic
feet of saturated vapor per gallon of liquid, is derived
as follows:
L~t:
W == weight of I gal of liquid, pounds.
M-= molecular weight of the hydrocarbon vapor.
C:::: compressibility factor.
p, c::: partial pressure of the hydrocarbon in the
vapor 1\t saturation, pounds per square inch
absolute.
z:::: number of cubic feet of saturated vapor at
60 F and 14.7 psia, per gallon of liquid.
p~.:: absolute pressure.
V ~-= vapor volume.
R:::: gas constant.
T::--= absolute tcmperatnre.
Then the number of cubic feet of vapor at 60 F and
atmospheric pressure containing 1 gal of liquid is:
379.~ we
M
A~ stated in Boyle's law, the volume of a vapor is
proportional to its partial pressure, Pv. therefore:
Zo:::- ('7(1..~ \\'C)(14.7\
1\1 p. )
The varnI' from motor gasoline contains hydrocar-
bons chidiy in the range of IJobutane, Tlbutane, iso-
pcntan~, npcntanc. iU1d the hexanes, with small amounts
of heavier hydrocarbons. The butanes and the pen-
tanes arc the principal components. In general, the
molecular weights of the vapors from gasolines or other
volatile products are unknown, this is also true as re-
gards the equivalent weights of 1 gal of liquid. How-
ever, the value of Z for mix.ed petroleum vapors can
be closely approximated by the relation:
Z = ~_0.-4M
p,
This relation:,;hip is applicable lo 60 F gal of condensed
vapor, and to VJpor volumes measured at 60 F, or com-
puted to that temperature. The molecular weight (M)
of a petroleum vapor in equilibrium with the liquid
product at 60 F can be approximated from:
Reid Vapor 10-Per-Cent-Point Slope
Pressure .
(Pounds) 0 1 2 3 '
"
6 84 74 69 66 63
7 82 72 67 64 61
8 80 70 66 63 60
9 78 69 64 62 .58
10 77 67 63 60 .57
11 76 66 62 59 .56
12 75 65 61 58 55
13 74 64 60 57 54
14 73 63 59 56 53
15 72 62 58 55 52
16 72 61 57 54 51
The molecular weights of petroleum vapors change
with the storage temperature, and this change is inde-
pendent of the Reid vapor pressure (RVP) of the
product, and only depends upon the 10-per-cent-point
slope. Change in molecular weight per degree change
. t 6.M f. f
In S orage temperature, _.. -, as a unction 0 lO-per-
I:.t
cent-point slope is:
10-Per-Cent-Polnt Stope
o
1
2
3
4
AM
At
0;000
0.034
0'0.049
0.059
0.068
The molecular weight decrea~es as the product tem-
perature decreases, and vice versa.
Applying the relation as expressed in equation (4)
to the conditions for equation (3), where the average
vapor pres~ure during the temperature increase is:
p,+p.
---2" ,
the average volume of vapor containing 1 gal of liquid
is, therefore:
(4)
(690-4M)(2) - 1.380-8M
- p,+P. -. --p~.H>;--
The total number of gallons of gasoline lost in the
vented volume of vapor then becomes:
G = V, ( _1"+P._._)[(P.+PI.-:-:-p~)(t~t_~~O) -lJ
1,3!i0-!iM P.+P.-.P. t,+460
Theoretically, this expression might be used to esti-
mate the maximum breathing loss caused by tempera-
ture change in any tank with a vapor space of fixed
volume.
In equation (5), the quantity within brackets repre-
sents the theoretical expansion of the vapor expressed
as a fraction of the vapor-space volume, VI, In fixed.
roof tanks, which have conservation vents with low
settings, the value of this quantity usually does not ex-
ceed 15 per cent, and nom1ally is lower. .
<')
-------
--
ApPENDIX II
It is possible to derive an approximate equation
which is premised upon the assumption that the changes
in t, p, and P arc relatively small when compared with
absolute values. Let A be used to denote these small
changes and let
(P.-p,) = (P.-p.)-A (P-p)
and
I, = t,+At
Then the quantity in brackets of equation (5) becomes:
[(~"-*_P'-:-P.-A(P"':::-P))(!I+A_~*4~~) -I ]
P,+P'-P. 1,+460
[( 1- [p~~~~.J)( I+Ct:~60J) -1 J
[1+(t;:~6-0) - (p~~~~~,) - (p~~;:~~JC,:}60)-I]
[/ ~. ) ( A(P-P)) ( A(P-p) )( At )]
,1,+460 - P.+P~-p, -P.+P.-P. t~+466
The last teoo is the product of two small quantities and
may be considered negligible. The expression becomes:
[C,:l6-0) - (p~~;.-~1-;)]
[(" t.-t, ") - ( (P.-p.)-(P.-p.,) )]
1,+460 p.+P.-p.
[Clt~~~O) + (p,~;:=pJ - (P.~;~p.)]
With a value of this low order, the quantity may be
written with little 10$s of mathematical accuracy, thus:
[(P'+PcP' )("+_4~0) -IJ
P.+P.-P. 1,+460
[( Ilt~~~O) I- (P.~~-;.~P.) (P.~;,~~P')]
Then the theoretical equation for breathing loss may be
expressed, with small error, thus:
G = v,C.j~t~'8M)[C.t~~o)
+ ( P,-P, ) ( P,-P, )]
P.+P,-p, P.+P.-p.
(Sa)
Equation (5a) gives a clearer concept of the nature
of breathing losses. Each factor and term has a definite
physical meaning. V I is the volume of the vapor space
in cubic feet. The factor l.;~: !:tM is the number of
gallons of liquid hydrocarbon contained in 1 cu ft of
vapor. The quantity within brackets is the total theo-
retical expansion expressed as a fraction of the vapor-
space volume. When the vapor-concentration factor
1':~;~P~M is multiplied by the vapor-space volume
V" it gives the approximate numher of gallons con-
tained in the vapor space. This, in turn, when multi-
plied by the quantity within brackets in equation (5a),
gives the theoretical loss r" in gallons, for the breath-
ing cycle, which is usually one day.
In the approximate equation (Sa), the theoretical ex-
pansion, in brackets, is hroken down into three parts.
33
The first term, -t;~~~O' is the expansion which results
from vapor-space temperature change. The second
term, -p P'p-::-PL_, represents the theoretical expansion
..+ ,-P,
which results from additional hydrocarbon evaporating
into the vapor space when rising liquid-surface tem-
perature causes an increase of true vapor pressure. The
third term, - ---P.. ~!'.I -, is subtracted from the first and
p..+P,-p,
second terms. It represents a reduction of the total ex-
pansion which results from compression caused by an
increase of the tank-gage pressure between the vacuum
and the pressure-vent settings.
Thus, the mechanism of breathing is basically quite
simple. Ideally, it should be possible to evaluate the
several factors and teoos in equation (Sa) and to
apply coefficients in the proper places in order to cal-
culate breathing losses for a given combination of con-
ditions. However, this is an enormously complicated
problem. A review of published data reveals wide dis-
crepancies in the evaluation of individual factors gov-
erning evaporation losses.
F PJ+P, f . (5) th .
actor I,380-8M 0 equatIon a, e approX1-
mate number of gallons per cubic foot of vapor, rep-
resents complete saturation of the vapor space and,
also, equilibrium with the liquid surface at all times. It
is the highest vapor concentration that can exist. Based
on Orsat analyses in 80,OOO-bhl tanks, McCullough,
et al.2 report: "There appeared to be no stratification of
air and vapor except for about an hour following the
inhalation period." This implies a very high degree of
saturation. Exhalation of saturated vapor seems a rea-
sonable assumption because most breathing-loss tests
were conducted either during standing storage or while
the tanks were slowly being emptied.
One tank manufacturer gives 45 per cent as the
average saturation of the vapors vented from an
80,OOO-bbl tank. A more nearly complete saturation
probably exists, except when liquid withdrawals are
rapid and the throughput is high. When the per cent of
saturation is low because of very high throughput, the
reduced evaporation loss usually is considered as a re-
duction in filling loss.
t,-ll d P,-PI
The teoos _4"60 an -p -+ P
ll+ a ,-P,
versial as vapor concentration. The temperatures, t,
and tl, are not susceptible to accurate measurement by
ordinary methods. A thermometer or other tempera-
ture-sensing element does not always give a true indi-
cation of the temperature of the surrounding vapor.
The transfer of heat by radiation may greatly affect the
temperature reading, particularly when the roof and
shell of the tank are hot and the vapor is quiescent.
Also, P, and p, are difficult to evaluate because the
liquid-surface temperatures, at which the true vapor pres-
are as contra-
-------
.--- -- - - --------"--_..
-----'------
EVAPORATION LOSs--CAUSES AND CONTROL
34
sures are desired, are obscure. The effective surface
fiJm is of molecular thickness, and no suitable means of
measuring its temperature has been devised. For prac-
tical purposes, however, the effective temperature is that
of the upper part of the liquid column. In addition, the
problem of degrec of saturation occurs again in the
evaluation of the efTcct of {lB - P I' The change of the
average partial pressurc of the vapor in the vapor space
may be Jaw whcn compared with p! -- plat the liquid
~urfacc because of stratification or incomplete diffusion
oi vapors in the vapor sracl~. Many, if not most, of the
published articles t1cg1cct the second term (the effcct of
vapor-pn'"surc change) as unimportant. They account
for all of thc expansion on the basis of temperature
t. . t I
(/:.mfl", One reference ,\ develops the formula
, I, I, '-I<'JI'
th:lt an:nunts for the vapor-pressure change and cites a
short-term test ,\n a IS,OOO-bbl tank with a lifter roof.
Lifter-roof movement or expansion was accounted for
by the assumptions:
I. Average daily vapor-space temperature change is It
times the atmospheric tempaature change.
2. Daily gasoline surface-temperature change is one-
tcnth of the atmospheric temperature change.
Smith and Harden . conclud~ that the effect of vapor-
pressure change is as great or greater than the breath-
ing dIect of the vapor in the tank because of the change
of vapor temperature. Thus, published data covers a
.d I' PB-PI f t
WI e range t,;va uatmg - --, ,- rom zero 0 an
- , Pa+Pr-PB
tz - t t
effect at least equal to the term -- _4 0,
11 -t- 6
Th I' f - I't L. I d .lh f .
e tern! P I' c:Jn 'JC eva llate WI all' ac-
, -1 r - fir
curacy. All of the v;lri,lbks arc accu£ atdy known ex-
cept Pro The ['r in (he denominator 1TJ,'y be neglected,
inasmuch as it is sl1lall when compared with Fa. The
value of fJr may he taken as the vapnr pressure of the
slored liquid at its ;Ivnage liquid-body temperature.
This will be lower t!1;\n the vapor pre.,,,urc at maximum
liquid-surface tCl11pCI atun: by cnough to account for
some incomplete satllratinn. In any event, a sizable
error in fll w1l1 nN seri,)usly anect the value of the
tam.
n. Filling LO!4'wI<
Theorctjc;\l considerations regarding fiJling losscs are
much simpler than thme relating to breathing losses.
Fewer variables have a direct clfed on their magnitude.
Basically, filling losses are caused by the displacement
of vapor from the tank by the introduction of liquid into
the tank. If the partial pressure of the hydrocarbon in
the vapor were PfJ' that is to say, the vapor is saturated,
the number of cubic feet of saturated gasoline vapor per
gallon of liquid would be obtained from equation (4):
z = 690-=~~
p.
The filling loss would be, therefore, 1 gal for every
690-4M .
- --- - cu ft pumped mto the tank, or 1 gal for every
Pv
(690-4M) (7.48) .
--------- gal pumped m. If VL gallons were
p"
pumped into the tank, the filling loss, therefore, would
be:
F p. VL
. = (690=-4M)(7:48)'
If M is taken equal to 61, then
3p. V L
F = -IO~OOO (6)
Eq uation (6) is the basic formula for filling losses.
However, experience has shown that a correction fac-
tor, K, must be applied to the equation to correct for
variation in saturation caused by frequency of turnover
and method of operating the tank. For practical ap-
plication, equation (6) usually will take the form of:
3p VL
F = 10;000 K
Where:
F = filling loss, in units of V L'
p= true vapor pressure, pounds per square
inch absolute.
V L = volume of liquid pumped in.
K == operation factor based on experience.
REFERENCES
I Original breathing-loss equation derived by H. C. Board-
man. See "Symposium on Evaporation Loss," Pr. ~ API 32
r I] 213-81 (1952). Equations appearing herein are modifi-
cations dcveloped by O. C. Bridgeman; sec "Some Phases of
the Problem of Evalualing Evaporation Losses from Petro-
leum Products by Means of Vapor Volume Measurements,"
Phillips Petroleum Co., Bartlesville, Okla., Phillips Report 1288-
55R (1955).
2 G. W. McCullough, H. R. Legatski, and H. J. Pidey, "Re-
ducing Losses of Volatile Liquids in Atmospheric Pressure Stor-
age," Natl. Petrol. News 38 [6] R122-30 (1946).
" H. C. Boardman, "Storagc of Volatile Pctroleum Products,"
P,'tml. Refiner 25 [4] 109-16 (1946).
. S. S. Smith and G. D. Harden, "Factors Affecting Conserva-
lIon of Products in Storage," Oil GasJ. 51 [10] 125-27 (1952).
-------
APPENDIX III-GENERAL INFORMATION
Symbolll and Abbreviations
Area
Coefficient of expansion, volu-
metric
Coefficient of heat transfer:
individual
overall
CompressibilIty factor
Concentration, volumetric
Conductance
Density
Diameter
Difference, finite
Diffusity of vapor
Film thickness, effective
Fugacity
Gas constant, universal
Internal energy
Internal energy per unit weight
Latent heat of evaporation
Length
Mechanical equivalent of heat
Molecular weight
Mole fraction in:
liquid
vapor
Mole ratio in:
liquid
vapor
Number, in general
Partial pressure or vapor pres-
sure
Pressure, total
Quantity of heat transferred
Radiation, intensity of
Radius
Rate of heat transfer
Resistance, thermal
Specific heat:
at constant pressure
at constant volume
Specific volume
Surface per unit volume
Surface tension
Temperature:
absolute
Thermal conductivity
Time
Volume:
total or per mole
liq uid
Weight, quantity of matter
Width, breath
Work
A; S
{J
h
U
C
c
1
ii;C
p
D
.:l
Dy
B
f
R; Ro
E
U
A
L
J
M
x
y
x
y
N
P
P
Q
N
r
q
R
c
Cp
c,
v
a
y
t
T
k
t
V
VL
W
b
W;W",
3.5
sq ft
increase in vol per unit vol per deg
temperature change
Btu per (hr) (sq ft) (deg F)
Btu per (hr) (sq ft) (deg F)
PV per RT
lb per cu ft; lb moles per cu ft
Btu per (hr) (deg F)
lb per cu ft
ft
sq ft per hr
ft
lb force per sq ft, atm
Btu; Btu per lb mole
Btu per lb
Btu per lb
ft
(ft) (lb force) per Btu
[Note: x and y used to denote equi-
librium value.]
No.
lb force per sq ft, atm
Btu
Btu per (hr) (sq ft)
ft
Btu per he
(sq ft) (deg F) per (Btu per he)
Btu per (lb) (deg F)
Btu per (lb) (deg F)
Btu per (lb) (deg F)
cu ft per lb
sq ft per cu ft
Ib force per ft; dynes per em
deg F or deg C
deg K or deg R
Btu per (hr) (sq ft) (deg F per ft)
sec; min; hr
cu ft; cu ft per lb mole
gal; bbl
lb
ft
Btu; pcu
-------
36
EVAPORATION LOSS-CAUSES AND CONTROL
-------
Multiply
Atm (atmospheres)
Atm
Atm
Atm
Atm
Bbl (42 U.S. gal)
Bbl
Bbl per day
Bbl per day
em
Cm of Hg
Cu ft
Cu ft
Cu ft of dry air (60 F)
Cu ft Ol water (60 F in air)
Ft
Ft of watcr (60 F in air)
Ft of watcr (60 F in air)
Ft of water (60 F in air)
o per eu em
o mol
Gal (U.S.)
Gal (U.S.)
Gal per hr
Gal of water (60 F in air)
In. .
In. of Hg
In. of Hg
Lb
Lb-mol
Lb-mol
Liter
Oz, avoirdupois
Oz, fluid
Oz, fluid
R (gas constant)
R (gas constant)
Specific gravity 60 F / 60 F
Temp (deg C + 273)
Tcmp (dcg C + 17.8)
Temp (deg F + 460)
Temp (deg F - 32)
Conversion Factors
By
14.7
760
29.92
33.93
1,013,250
42
5.615
1.75
0.234
0.3937
0.1934
7.481
28.32
0.076
62.30
30.48
2.244
0.4326
62.30
62.43
22.414
231
3.785
0.5715
8.328
2.54
0.03342
0.4912
453.6
379.5
359
I,OdO.028
28.35
1.805
29.57
82.06
1,545
8.328
1.0
1.8
1.0
0.5556
---~-_._-
To Obtain
lb per sq in.
mm of Hg (32 F)
in. of Hg (32 F)
ft of water (60 F)
dynes per sq em
gal (U.S.)
eu ft
gal per hr
eu ft per hr
in.
Ib per sq in.
gal
liters
Ib of air
Ib of water
em
em of Hg
lb pcr sq in.
lb per sq ft
lb per eu ft
liters at 0 C and 1 atm
eu in.
liters
bbl (42 U.S. gal) per day
lb
em
atm
lb per sq in.
g
eu ft vapor, 60 F and 1 atm
eu ft vapor, 32 F and 1 aim
eu em
g
eu in.
cu em
(eu em) (atm) per (g mol) (deg K)
ft-lb per (lb-mol) (deg R)
Ib per gal (in air)
abs temp, deg K
temp, deg F
abs temp, <.leg R
temp, deg C
-------
ApPENDIX III 37
DEceREE FAHRENHEIT = 1.8 C +32 DEc;REE CENTlceRADE = DEG F -32
1.8
OEce C DEce F DEG C DEce F DEce C DEG F DEG C DEG F DEG C DEG f' DEG C DEG F
30 210
0 100 300 SOO 700
-270 1300
-450 580
-260 40 950
600 520 1350
10 50 120 250 320
-240 -400 620 750
60 540 1000 1400
-220 340 &40
20 140
70
-350 560 1450
300 660
80 1050 800
-200
30 160 3&0 680 1500
90 S60
-300
-'6Q 700
1100 1550
100 350
180 380 600 850
40
-160 7;!0
-250 110
1600
740 620 1150
-140 50 120 200 400
400 760 900 1650
-200 130 640
-120 780
1200 1700
60 140 220 420
800 660
-100 -150 950
150 4S0 1750
820 1250
70 240 440 680
- 80 160
-100 1600
840
170 1000
700
- 60 80 260 500 460 660 1300
180
- 50
880
- 40
- 190
260 460 900
- 20- 200 550
0
920
100 -- 210 570 500
300
0 + 30
FIG. I-Temperature Conversion Chart.
-------
Name
Paraffins
Methane
Ethane
Propane
nButane
l.wbutane .
...
CIO
nPentane
Isopentane
nHexane . . .
Isohexane (2-methyl pentane)
2,2-Dimethylbutane (neohexane)
2,3-Dimethylbutane (dU.ropropyl)
nHeptane . . . . .. "".
2,2,3- Trimethylbutane (triptane)
nOctane .' ... .. .... ..
2,5-Dimethylhexane (diisobutyl)
2,2,4- T rimethylpentane (isooctane)
nNonane
nDecane ... .. ..
Cetane (nhexadecane)
Monooletins
Ethene (ethylene)
Propene (propylene)
I-Butene
Isobutene
cis-2-Butene ..
trans-2-Butene
I-Pentene .
I-Hexene
Cetene
"""'" .
......... .
Diolefins.
Propadiene (allene)
1,2-Butadiene
1,3-Butadiene
Acetylenes
Ethyne (acetylene)
Propyne
APPENDIX IV-PROPERTIES OF PURE HYDROCARBONS
'"
"3
E
..
o
1.1.
ClL
CJi.
c.H.
c.H,.
c.H..
"" c.Hu
c.Hu
c.H"
c.H"
c.H"
c.H"
c'Hu
C,H,.
CJ{..
CJ{..
.. c.H..
c.H",
C,.H.,
c..u..
c.H.
Coll.
CJL
CJL
CJL
c.H.
c.H,.
c.H ,.
C,JL.
Coll.
c.H.
CJL
.. C.H.
....... CJL
TABLE I-Properties of Pure Compound.
;...
8~
U'-
_u
o~
:E
16.042
30.068
44.094
58.120
58.1"20
72.1A6
72.146
86.172
86.172
86.172
86.172
100.198
100.198
114.224
114.224
114.224
128.250
142.276
226.432
28.052
42.078
56.104
56.104
56.104
56.104
70.130
84.156
224.416
40.062
54.088
54.088
26.036
40.062
u
S ~
u 1.1.
u 0
0. >- \0
11)...-.....
~>I.I.
.:; Eo
2'O~
...J
0.5077 .
0.5844 .
0.5631 .
0.6312
0.6248
0.6640
0.6579
0.6540
0.6664
0.6882
0.6945
0.7068
0.6980
0.6962
0.7217
0.7341
0.7773
0.5220 .
0.6013 .
0.6004 .
0.6271 .
0.6100 .
0.6457
Ct'6780
0.7850
0.658 .
0.6272 .
IIG~
cu
== tG=-
~~'ii
..,,--:2
CI:I...~
E .E ..c
"0'"
~~I.I.
-258.68
-127.53
- 43.73
31.10
10.89
96.93
82.13
155.73
140.49
121.53
136.38
209.17
177.59
258.20
228.39
210.63
303.44
345.42
548.23
-154.68
- 53.86
20.73
19.58
38.70
33.58
85.94
146.27
544.77
- 30.1
51.53
24.06
-119. t
- 9.80
...
CII",,,C
U~ U
..cc
:1:1-
~O4,).-.
u~; u
"''-'':;:t'"
~ 1.1. O".:!
.. II) 0
oo..~
~8&<
>
15.570
20.44
4.956
6.767
9.856
7.404
1.620
3.374
0.537
1.101
1.708
0.179
19.115
6.006
...
= ~
"0 .-:::
~"'u
lIGu"c
=~~
.- 1:10...
Nu..c
~Q 0:1
u: --1.1.
-296.46
-297.89
-305.84
-217.03
-255.28
-201.50
-255.82
-139.63
-244.61
-147.77
-199.37
-131.10
- 12.84
- 70.24
-132.16
-161.28
- 64.33
- 21.39
- 64.70
-272.47
-301.45
-301.63
-220.63
-218.04
-157.99
-265.40
-219.67
+ 39.42
-213.
-213.18
-164.05
-114.
-152.3
.a
g,Jl~
E i.::
U~ u
!- "C
- =
B--~
.- f..c
'E:I 0:1
U"'I.I.
-115.78
90.32
206.26
305.62
274.96
385.92
370.1
454.5
436.9
421.2
440.9
512.62
497.
565.2
530.
520.07
613.0
655.0
844.
49.82
197.4
295.6
292.51
311.
311.
394.
248.
306.
97.4
251.
f
i""c
~8.g~
"'-~~£
- c: fE
B:lCIIO
.: cI: ~
1: --II) <
U
673.1
709.8
617.4
550.7
529.1
489.5
483.
440.
440.1
450.7
455.4
396.8
437.2
362.1
362.
374.7
332.
304.
206.
742.1
6i>7.
583.
579.8
600.
600.
586.
628.
90S.
...CIa
'0 :~ 8-
-09 0::1
c_=-
~f!-~~
"".C as.......~
"'oE...c
=0."=:1
~CII~O 0
j>""'~~
219.22
210.41
183.05
165.64
157.51
153.59
147.13
143.95
138.67
13 1.24
136.08
135.99
124.20
129.5 1
122.8
116.69
123.74
118.68
97.2
207.57
188.18
167.94
169.48
178.91
174.39
154.46
-
-------
All;.yl Benzenes (Aromatics)
Benzene c.H. 78.108 0.8846 176.18 3.224 + 41.96 553.01 714. 169.34
Toluene c.1i. 92.134 0.8719 231.12 1.032 -138.98 609.5 1 590. 156.2
Etbylbenzene c.H. 106.160 0.8718 277.14 0.371 -138.96 655.8 540. 145.7
oXylene c.H. 106.160 0.8848 291.94 0.264 - 13.33 678.3 530. 149.1
mXylenc . , . .. """., c.H.. 106.160 0.8687 282.39 0.326 - 54.17 654.9 510. 147.4
pXylenc . . . . . . . . .. .. c.H. 106.160 0.8657 281.03 0.342 + 55.87 653.1 500. 146.1
Isopropylbenzene (cumene) c.H.. 120.186 0.8663 306.31 0.188 -140.86 685. 400. 134.3
Allyl Cycloparaffins (Naphthenes) CJL.. 70.130 0.7505
CyclopentaDe .. .. ""'" 120.67 9.914 -136.96 461.48 654.7 167.34
Metbylcyclopentane c.H.. 84.156 0.7535 161.26 4.503 -224.42 499.30 549. 147.83
Cyclobexane ... c.H.. 84.156 0.7834 177.33 3.264 + 43.80 153.7
Metbylcyclohexane ""..""" C.H,. 98.182 0.7740 213.68 1.609 -195.87 138.9
Miscellaneous Organic Compounds
Acetone C.H.O 58.078 0.7963 133.03 7.53 -138.5
Ch10rex . . . . . . . " c.H.C1.O 143.018
oCrcsol """"'" c.H.O 108.134
mCresol c.H.O 108.134
pCresol . c.H.O 108.134
Dichlorethylene . C.H.CI. 96.950
Ethyl alcohol. .. ...... C.H.O 46.068 0.7939 172.99 2.313 -173.9
Furfural. . ." """""""".-'. c.H.D. 96.082
... Methyl alcohol ... ...... ClLO 32.042 0.7962 148.12 4.63 -143.82
\0 Methyl ethyl k.etone c.H.O 72.104 0.8103 175.26 3.16 -123.3
N aphtbalene ......... .........,. C..H. 128.164 424.32 +176.52
1- Methylnaphthalene . . . . . . .. CuR. 142.190 1.0246 472.36 - 23.03
Nitrobenzene . . . . . . . . .. c.H.NO. 123.108
Phenol c.H.OH 94.108
Styrene ........ c.H. 104.144 0.9111 293.4 - 23.13
I-MethyJstyrene . . .. ........ , CJL.. 118.170 0.9154 329.68 - 9.58
Trichlorethylene CoMCt. 131.399
Miscellaneous
Air .. .......... 28.966 0.856 * -318. -221. 547. 92.
Hydrogen H. 2.016 0.071 * -423. -434. -400. 188. 194.
Oxygen ... ........ O. 32.000 1.140; -297. -361. -182. 730. 92.
Nitrogen ........ N. 28.016 0.808; -320. -346. -233. 492. 86.
Carbon monoxide. .. CO 28.010 0.801 * -314. -341. -218. 514. 91.
Carbon dioxide. . .. CO. 44.010 1.56 t -109. t 88. 1,013.
Hydrogen sulfide.. ILS 34.082 0.79 * - 76. 394. -122. 213. 1,306. 236.
Sulfur dioxide. . . . . . .. ...... so. 64.066 1.46 * 14. 84. - 99. 425. 1,230. 171.
Water. . . . .. ....,...... """"" lLO 18.016 1.000 212. 0.95 32. 705. 3,206. 970.
Ammonia. . . . .. ........... NIL 17.032 0.618 - 28. 212. -108. 271. 1,650. 589.
. At saturation pressure.
t At sublimation point.
* Density at boiling point, scam per cubic centimeter.
-------
40
EVAPOR.ATION LoSs--CAUSES AND CONTROL
TABLE 2-Denahy of LI.ht Hydroearbona - a' 60 F
Cubic Feet
Pounds Pounds Pound- Pound- of Vapor
Molecular per per Moles per Moles per per Barrel
Name Formula Weight Barrel Gallon Barrel Gallon of Liquid t
Paraffin
tV, ,aane * . . . , . . . . . .. CH. 16.042 87 2.07 5.42 0.1290 2,057
Ethane * ......... CoHo 30.068 149 3.55 4.96 0.1181 1,882
Propane .....,.. CoHo 44.094 178 4.23 4.03 0.0960 1,530
lsobutane .. C.H.. 58.120 197 4.70 3.39 0.0808 1,287
nButane ""'."" " C.H.. 58.120 205 4.87 3.52 0.0838 1,336
1.l'Opentane CoH.. 72.146 219 5.21 3.03 0.0722 1,151
nPentane ColI.. 72.146 221 5.26 3.06 0.0729 1,162
I1Hexane .. ColI.. 86.172 232 5.54 2.70 0.0642 1,024
nHeptane ........... CH.. 100.198 241 5.74 2.40 0.0573 912
110ctane CoM.. 114.224 248 5.89 2.17 0.0516 822
nNonane .... ColI.. 128.250 253 6.02 1.97 0.0469 748
nDecane ....,..... CuJi. 142.276 257 6.12 1.81 0.0430 685
Unsaturates
Ethylene ~ ........, C.H. 28.052. 153 3.65 5.46 0.1301 2,072
Propylene CoHo 42.078 183 4.35 4.34 0.1034 ! 1,647
I-Butene. . CM. 56.104 210 5.01 3.74 0.0893 1,417
lsobutene CM. 56.104 210 5.00 3.75 0.0892 1,422
cIs-2-Butene .. "..",. C.H. 56.104 220 5.23 3.91 0.0932 1,486
trans-2-Butenc C.Ho 56.104 214 5.09 3.81 0.0906 1,444
I-Pcntene .. CoM.. 70.130 226 5.39 3.23 0.0768 1,224
I-Hexene ..,.. ColI.. 84.156 238 5.65 2.82 0.0672 1,071
I-Heptene CH.. 98.19 246 5.85 2.50 0.0595 949
I-Octene .' C.H.. 112.2 252 6.01 2.25 0.0535 853
1,2-Buladiene C.H. 54.088 231 5.49 4.26 0.1015 1,616
1.3-Hutadienc C.H. 54.088 220 5.23 4.06 0.0967 1,541
. As liquids corrected for huoyoncy of air. See Table I for specific aravity of compounds not listed.
t At 60 F and one atmosphere as a perfect lias.
* Based on ap{>arent density in solution in butane.
~ Based on raho of densities of propylene to propane times the density of ethane.
-------
0.20
0.30
0.40
O.~O
0.60
101
I-
::>
..J
o
If)
CD
«
J:
IJ
~
0.70
0.80
0.90
1.00
APPENDIX V-VAPOR PRESSURE CHARTS
S
21 0
43
2
..,
a::
::>
3 If)
If)
..,
4 a::
Q.
a::
o
& Q.
~
8 0
9 ....
a::
10
12
14
16
18
20
S . SLOPE OF THE ASTM DISTillATION CURVE AT
10 PER CENT EVAPORATED =
DEG F AT 15 PER CENT MINUS DEG F AT 5 PER CENT
10
IN THE ABSENCE OF DISTillATION DATA THE FOllOW-
ING AVERAGE VALUE OF S MAY BE USED:
MOTOR GASOLINE
AVIATION GASOLINE
liGHT NAPHTHA (9-14 PSI
NAPHTHA (2-8 PSI RVP)
RVP)
3
2
3.5
2.5
120
110
100
90
80
70
&0
50
40
30
20
10
o
Source: Nomograph drawn from dalll of the NAtional nureau of Standards.
FIG. I-Vapor Pr~..ure. of C..ollne. .nd Flnl.hed I'elroleum Product8-1 p.1 to 20 pal RVP.
41
I.~O
1&.1
IX
«
::>
o
If)
a::
..,
Q.
If)
o
z
::>
o
Q.
Z
2.00
2.~0
3.00
3.50
4.00
101
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a:
Q.
a:
o
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>
~.OO
&.00
7.00
8.00
....
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a:
...
9.00
10.0
11.0
12.0
13.0
14.0
15.0
I b.O
17.0
18.0
19.0
20.0
2.1.0
- 22.0
23.0
2.4.0
...
..,
J:
Z
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a::
J:
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101
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a::
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....
o
z
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~
a:
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D.
~
....
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-------
42
EVAPORATION Loss--CAUSES AND CONTROL
0.2
0.3
0.4
0.5
w
~
::>
.J
o
a
5 w
a:
b
1
5 = SLOPE OF THE ASTM DISTILLATION CURVE AT
10 PER CENT EVAPORATED ~
DEG F AT 15 PER CENT MINUS DEG F AT 5 PER CENT
10
IN THE ABSENCE OF DISTILLATION DATA THE FOLLOW-
ING AV E RAGE VALUES OF S MAY BE USED:
MOTOR GASOLINE
AVIATION GASOLINE
LIGHT NAPHTHA (9 - 14 PS I
NAPHTHA (2-8 PSI RVP)
RVP)
3
2
3.5
2.5
120
110
100
90
80
70
60
50
40
30
10
o
Source: Nomograph drawn from data of the National Bureau of Standards.
FIG. 2-Vapor PrcR~ur"lI of CaRoline!! and Finl!!hf'd Pf'lrol"um Prodncts--I pili to 7 pili RVP.
I
U
Z
- 0.8
--- 0.9
It.J
a:
«
::>
d
o
a.
- 1.0
z
W
0:
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- 2.0
- 3.0
1.1
.J
n::
~
4.0
l
I
~
[:
5.0
~
W
J:
Z
It.J
a:
J:
«
IL.
~
c(
a:
It.J
a.
~
w
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-------
ApPENDIX V
ILl
I-
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J
o
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IG
ct
:I:
V
Z
ILl
a:
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a:
ILl
0-
Il)
a
z
:)
o
(L
z
ILl
a:
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II)
II)
ILl
a:
0-
a:
o
0-
ct
>
ILl
:)
a;
I-
0.80
0.90
1.00
2.0
3.0
4.0
5.0
6.0
7.0
8.0
9.0
10.0
- 11.0
12.0
13.0
5
ILl
6 ~
II)
7 II)
ILl
8 a:
(L
9
10 ~
I I 0..
12 ~
13
14 e
ILl
a:
S 8 SLOPE OF THE ASTM DISTILLATION CURVE AT
10 PER CENT EVAPORATED.
DE& F AT 15 PER CENT MINUS Dft; F AT 5 PER CENT
10
FOllOW -
IN THE ABSENCE OF DISTilLATION DATA THE
IlliG AVERAGE VALUES OF S MAY BE, USED
MOTOR GASOLINE
AVIATION GASOLINE
LI&HT NAPHTHA (9 -14 PSI RVP)
NAPHTHA (2-8 PSI RVP)
3
2
3.5
2.5
120
110
100
90
80
70
60
50
40
30
20
10
o
14.0
Soura: Nomograph drawn from data of the National Bureau of Standards.
FIG. 3-Vapor PrclI8ures of Gasoline, and Finished Pelrol('um Produels-S,psi to 14 psi RVP.
43
I-
ILl
:I:
Z
ILl
0::
:z:
ct
...
II)
ILl
4J
a:
U
ILl
o
Z
ILl
a:
:)
~
a:
ILl
0-
~
ILl
...
-------
44
EVAPORATION LOSs-CAUSES AND CONTROL
1.8
2.0
120
3.0
110
IA.I 4.0 100
~
...I
0
II) ~
Q) 90 i&:i
« :a::
:a:: '.0 z
V kI
~ 0::
:a::
IU 80 ~
0:: kI
« 6.0 a: on
a ;:) kI
II) kI
II) 12 II) 0::
kI 70 \J
0:: 13 a: kI
IA.I 7.0 14 Q. 0
CL
II) " a: ~
a 16 0
z 18 Q. 60 kI
;:) &.0 ~ 0:
o ~
CL 20 ~
a
z IA.I 0:
9.0 0: IA.I
IA.I .50 Q.
0:: ~
;:) kI
II) 10.0 ~
of)
IA.I
a: 40
Q. 11.0
0::
0 S . SLOPE OF THE ASTM DISTILLATION CURVE AT
CL 12.0
« 10 PER CENT EVAPORATED.
> 30
IA.I 13.0 OEG F AT 15 PER CENT MINUS DEG F AT .5 PER CENT
;:) 10
0::
I- 14.0
IN THE ABSENCE OF DISTILLATION DATA THE FOLLOW- 20
15.0 ING AVERAGE VALUES OF S MAY BE USED:
16.0 MOTOR GASOLINE 3
17.0 AVIATION GASOLINE 2 10
LIGHT NAPHTHA (9-14 PSI RVP) 3.5
18.0 NAPHTHA (2-8 PSI RVP) 2.5
19.0 0
20.0
Z 1.0
22.0
23.0
24.0
25.0
Nomo.raph drawn from data of the National Bureau of Standards.
Source:
FIG. 4--Vapor Prellurel 01 Galollne. and Flnllhed Petroleum Producta--12 psi to 20 pll RVP.
-------
,-- -------
ApPENDIX V
---- ---'---. ----
45
---
140
130
.... 120
~
:)
oJ
0
If)
IrI 2 110
<
::J: 2
...,
Z t-
100
.... I&J
a:: 3 ::J:
< 3 z
:) ...
c:J 90 a:
If) 4 J:
I&J «
a:: a: IL
w 4 ::)
Q. en ~ en
en 80 I&J
If) I&J I.J
o a: 0::
Z Q. C)
:) ~ I.LI
o a: 70 0
Q.
0 Z
Z Q..
6 «
.... > I&J
II:: 60 0::
::> 0 :)
If) 7 I&J 10 t-
If) a: c(
.... a:
II:: 8 ~O W
Q. Q..
II:: ~
o 9 I&J
Q. t-
~ 10 I~ 40
....
::> II
II::
t- 12 30
13
14 20
' I~
10
20 0
Z~
FIG. s.-Vapor Pre8lure. 01 Crude 011.
-------
APPENDIX VI-METEOROWGICAL DATA
TABLE l--Solar Data, United State8
Top Line: Monthly and annual duration of sunshine, expressed in hours.-
Bottom Line: Total solar and sky radiation received on a horizontal plane
expressed in 100 Btu's per square foot per month.
Stations Ian Feb Mar Apr May Iun Jul Aug Sep Oct Nov Dec Year
Albuquerque 211 282 268 342 345 393 357 332 304 300 288 226 3,648
N.Mex. 302 380 518 630 730 737 754 670 545 503 346 226 6,341
Atlanta 142 203 219 240 267 347 325 317 293 253 159 140 2,905
0.. 275 351 522 571 676 753 666 618 524 441 285 241 5,923
Bismarck 131 176 227 234 299 268 337 307 216 176 177 183 2,731
N. Dale 181 237 415 472 662 597 675 580 403 290 196 149 4,857
Boston 128 156 260 214 214 265 343 287 225 231 182 151 2,656
Mass. 160 214 326 402 452 504 513 455 353 256 139 124 3,898
Boulder 203 260 232 292 293 358 323 328 285 253 237 227 3,291
Colo 240 294 450 530 550 597 609 530 470 367 266 222 5,125
Charleston 182 231 245 267 311 375 346 352 279 290 229 229 3,336
S.C. 313 350 463 596 660 670 640 602 482 409 352 272 5,809
Chicago 114 155 370 184 277 319 328 255 248 140 138 103 2,631
III. 114 169 286 389 500 548 520 495 367 245 144 102 3,879
Columbia 170 211 239 292 334 362 392 279 289 175 197 120 3,060
Mo. 207 268 371 455 548 616 680 581 478 354 233 182 4,973
Davis 117 132 184 282 373 370 429 370 365 313 141 73 3,149
Calif. 217 300 452 615 740 770 794 702 557 428 261 155 5,991
Dodge City 197 253 257 289 241 377 371 340 333 271 258 215 3,402
Kans. 282 420 500 583 569 785 731 661 478 428 341 284 6,062
East Lansing 89 128 205 176 271 294 339 265 203 141 100 75 2.286
Mich. 143 198 296 356 427 491 525 467 355 245 139 105 3,747
EI Paso 269 287 298 349 403 407 393 323 336 319 302 275 3,961
Texas 402 470 625 742 815 818 786 746 667 550 430 382 7,433
Fort Worth 131 255 213 194 237 383 337 319 341 252 243 192 3,097
Texas 260 500 532 616 696 835 795 771 677 503 423 314 6,922
Fresno 190 175 257 340 412 413 430 410 366 339 166 104 3,602
Calif. 197 294 474 616 730 766 775 696 566 439 289 194 6,036
Friday Harbor 58 63 191 164 242 198 258 136 150 119 37 62 1,678
Wash. 100 144 296 472 610 658 682 582 400 240 128 93 4,405
Gainsville 150 216 245 210 272 259 270 272 172 240 198 179 2,683
Fla. 256 327 474 568 646 562 520 456 402 368 370 240 5,188
Great Falls 107 ]39 190 224 294 296 406 306 261 212 137 163 2,735
Mont. 161 236 422 497 618 622 758 602 469 328 188 154 5,055
Greensboro ]47 191 224 249 267 343 326 294 316 307 212 221 3,097
N. C. 245 341 453 565 653 755 710 625 550 432 241 206 5,776
J ndianapolis 123 155 215 223 233 310 403 328 300 199 141 111 2,741
Ind. 1.~5 238 379 495 580 642 690 540 470 274 192 129 4,784
Ithaca 49 ] 17 182 210 270 281 309 201 171 133 97 56 2,126
N. Y. I.D 203 287 351 482 544 570 530 428 280 144 114 4,076
Lincoln 176 212 218 267 288 367 368 263 302 163 227 187 3,038
Nebr. 216 273 384 463 555 616 634 556 455 354 244 199 4,949
Little Rock \07 207 181 235 282 373 347 356 306 216 218 145 2,973
Ark. 210 370 427 540 622 722 715 646 535 354 287 200 5,628
Madison 134 173 2.~0 207 260 319 338 290 221 188 131 112 2,623
Wis. 173 241 354 446 538 584 600 514 389 273 167 133 4,412
Miami 259 261 313 266 252 235 285 321 276 221 248 273 3,210
Fla. 348 377 475 516 560 539 536 525 478 436 372 345 5,507
Minneapolis 115 136 197 206 251 259 281 21:>7 147 138 118 113 2,228
Minn. 148 220 331 422 616 722 608 577 328 225 174 146 4,517
46
-------
ApPENDIX VI 47
TABLE 1-(Coatl8aed)
StatiODs Jan Pcb Mar Apr May JUD Jul AU8 Scp Oct Nov Dee Year
Nashville 159 194 166 234 204 32.5 316 271 274 200 183 12.5 2,651
TeDD. 1.54 22' 348 455 460 580 .576 .520 427 339 227 148 4,459
Now Orloaaa 160 243 239 2.5.5 268 312 246 310 261 251 215 173 2,933
L&. 245 298 400 475 .520 .527 490 490 416 434 322 240 4,849
Newport 122 153 254 250 ]83 234 243 224 170 179 158 129 2,299
R. I. 171 268 365 460 .562 .592 .594 .530 422 308 208 162 4,849
New York 143 165 240 2.53 231 30.5 328 2.50 214 218 17.5 176 2,698
N.Y. 134 114 332 419 .504 .53.5 .542 462 372 293 183 139 4,149
Oklahoma City ]76 258 223 262 242 382 388 34.5 328 221 2.50 208 3,283
Okla. 290 395 439 .522 .5.52 789 795 746 622 447 382 318 6,297
Phoeoix 266 296 306 381 410 407 387 396 361 326 302 2.51 4,089
Ariz. 379 4.56 59.5 720 826 825 760 730 646 .542 400 337 7,216
Plttsburah 69 85 154 212 220 274 315 247 216 119 84 47 2,042
Pa. 116 160 2.54 3.50 470 .52.5 .540 470 3.52 24.5 144 94 3,720
Put-in-Bay 90 141 223 240 291 328 340 263 231 140 14.5 79 2,.511
0.0 131 209 333 424 436 61.5 631 .570 42.5 297 174 108 4,3.53
Rapid City 143 172 170 184 226 244 344 278 244 198 180 158 2,.544
S. Oak. 206 289 44.5 515 611 668 684 620 498 379 237 184 5,336
Riverside 215 271 232 232 277 301 361 293 316 287 231 242 3,2.58
Calif. 285 329 450 .546 610 636 667 60.5 .520 430 310 258 5,646
Salt Lake City 122 119 200 293 342 32.5 394 362 304 289 247 162 3,159
Utab 194 264 405 .534 634 620 720 596 484 343 202 1.51 .5,147
San Antonio 159 236 223 220 314 316 3.57 339 324 273 2.50 221 3,232
Texas 349 364 490 537 630 686 726 690 .577 484 358 302 6,193
Tampa 238 259 294 2.57 321 313 277 310 266 303 2tS 238 3,291
Fla. 392 443 592 620 690 63.5 .570 .587 .502 495 405 369 6,300
Twin Palls 48 177 194 294 359 246 338 332 30.5 2.52 213 133 2,891
Idaho 188 262 407 .519 641 677 692 610 49.5 360 216 1.5.5 .5,222
Washlnaton 1S7 200 241 243 231 333 367 266 261 20.5 139 129 2,772
D.C. 200 248 3.56 4.50 .546 .572 576 507 413 331 224 177 4,600
Sourc,: U.S. Department of Commerce, Weather Bur88u, Washington, D. C.
-------
TABLE 2-Solar Data, Canad..
Top Line: Monthly and annual duration of sunshine, expressed in hours.
Bottom Une: Total solar and sky radiation received on a horizontal plane
expressed in 100 Btu's per square foot per month.
Stations Jan Feb Mar Apr May Jun Iul Aug Sep Oct Nov Dec Year
Calsary 109 133 159 194 254 239 316 265 191 165 118 102 2,245
AHa. 126 196 343 498 618 609 686 572 432 252 144 103 4,579
Edmonton 79 119 169 222 253 250 303 269 188 153 98 75 2,178
AHa. 11" 207 343 498 584 598 686 572 399 241 122 80 4,444
Fort WiUiam
Onto 137 207 377 487 561 587 618 526 343 217 105 105 4,270
Halifax 92 III 153 165 189 199 239 212 161 137 88 89 1,835
N. S. 172 238 343 443 572 576 618 515 376 286 166 114 4,419
Kamloops 64 105 176 231 250 260 322 286 214 151 69 50 2,178
B.C. 114 181 320 454 589 620 652 538 387 229 111 86 4,281
London
Ont. 126 227 343 443 572 587 618 515 398 263 144 126 4,362
Montrcu. 76 101 145 168 205 222 243 220 169 124 70 60 1,803
P. Q. 137 258 400 465 572 609 618 515 410 275 155 137 4,551
Moose Jaw 92 121 157 210 257 273 334 290 204 159 104 87 2,288
Sask. 126 227 400 487 572 609 686 538 388 240 133 114 4,520
Ottawa 91 116 150 186 232 253 273 250 177 136 80 72 2,016
Onl. . 137 227 389 498 572 609 629 515 410 240 122 114 4,462
Quebec 83 106 145 163 195 209 225 209 155 119 69 67 1,745
P. Q. 171 248 400 465 572 609 629 515 387 275 155 126 4,552
Resina 108 126 163 216 252 244 329 285 205 170 98 98 2,294
Sask. 126 227 400 487 572 609 686 538 388 240 133 114 4,520
St. John 114 123 153 160 207 200 206 204 168 145 102 99 1,881
N. B. 172 258 366 443 572 576 618 515 388 274 155 114 4,451
St. lohn's
Nfld. 149 186 320 376 515 573 572 446 343 252 122 92 3,946
Saskatoon
Sask. 126 217 389 498 583 609 686 538 354 229 122 92 4,443
Toronto 77 107 149 184 224 260 287 256 200 151 85 68 2,048
ODt. 126 186 343 443 549 587 606 515 387 252 144 103 4,241
Vancouver 48 82 129 ]78 232 226 287 268 178 112 53 39 1,832
B. C. 91 155 286 443 572 609 629 515 387 206 111 80 4,084
Windsor
Ont. 126 186 343 443 572 609 629 515 398 286 155 114 4,376
Winnipeg 100 131 168 204 247 252 291 263 177 127 86 78 2,124
Man. 137 238 400 498 595 609 629 538 376 228 122 103 4,473
Sn/4ra: Melcorolollical Division of the Dcpnrll11cnt of Transport, Ollawa, Onl.
TABLE 3-Anrugc Atmo8pheric Temperature, Dearee! Fahrenheit, United State.
Top Line: Maximum.
MiJdle Line: Minimum.
Bottom Line: Mean.
Stations Jan Feb Mar Apr May Jun Jill Aug Sep Oct Nov Dee Year
Albuquerque 47.3 53.0 60.8 69.8 78.6 88.5 90.6 88.5 82.1 71.1 57.7 47.4 69.6
N. Mex. 21.9 26.1 31.8 39.7 48.3 57.4 62.9 61.2 54.1 42.0 29.8 22.5 41.5
34.6 39.6 46.3 54.a 63.5 73.0 76.8 74.9 68.1 56.6 43.8 35.0 55.6
Allanta 51.9 54.6 62.2 70.9 79.3 86.1 87.6 86.5 82.1 71.9 60.8 52.5 70.5
Ga. 35.7 37.1 43.3 51.4 59.9 67.3 69.7 69.0 64.4 54.4 43.1 36.7 52.7
43.8 45.9 52.8 61.2 69.6 76.7 78.7 77.8 73.3 63.2 52.0 44.6 61.6
Binghamton 33.4 33.3 43.0 55.8 68.3 77.3 81.9 79,5 73.1 61.2 47.3 35.9 57.5
N. Y. 17.3 ]6.1 25.2 35.8 46.2 55.0 59.5 57.3 50.9 40.5 31.8 21.2 38.1
25.4 24.7 ~4.1 45.8 57.3 66.2 70.7 68.4 62.0 50.9 39.6 28.6 47.8
Bismarck 11I.t! 22.4 35.1 54.7 66.7 75.5 113.2 81.5 71.1 57.7 38.9 25.5 52.6
N. Dak. -2.4 J.h 14.7 31.5 42.5 52.5 57.9 55.2 45.1 33.3 18.4 5.7 29.7
8.1 12.0 24.9 43.1 54.6 64.0 70.6 68.4 58.1 45.5 28.7 15.6 41.2
48
-------
TABLE 3--(Contlnucd)
Stations Jan Feb Mar Apr May IUD Iul Aug Sep Oct Nov Dee Ycar
BostOD 36.5 36.3 44.4 54.8 66.1 75.5 80.7 78.4 71.9 62.0 50.4 39.6 58.1
Mass. 21.1 20.8 29.0 38.7 48.9 58.0 63.9 62.4 55.8 45.9 35.7 25.3 42.1
28.8 28.6 36.7 46.8 57.5 66.8 72.3 70.4 63.9 54.0 43.1 32.5 50.1
Casper 33.3 37.5 42.4 55.7 64.6 75.4 86.8 85.1 74.1 60.9 44.8 36.4 58.1
Wyo. 12.7 16.4 20.1 31.0 38.9 47.2 55.3 53.8 43.8 34.6 23.5 17.5 32.9
23.0 27.0 31.3 43.3 51.8 61.3 71.1 69.5 59.0 47.8 34.2 27.0 45.5
Charleston 58.5 59.8 65.7 72.4 79.9 85.8 87.9 87.3 83.1 74.9 66.0 59.2 73.4
S. C. 43.3 44.5 50.2 57.3 65.9 72.6 75.1 74.6 70.8 60.8 50.7 44.1 59.2
50.9 52.2 58.0 64.9 72.9 79.2 81.5 81.0 77.0 67.9 58.4 51.7 66.3
Chicago 32.0 33.9 43.2 54.9 65.9 75.8 81.1 79.2 73.0 61.7 47.0 35.7 57.0
III. 18.0 20.1 29.2 39.6 49.4 59.7 65.8 65.0 57.9 46.8 33.6 23.3 42.4
25.0 27.0 36.2 47.3 57.7 67.8 73.5 72.1 65.5 54.3 40.3 29.5 49.7
Cleveland 34.6 35.0 43.4 55.0 66.5 76.1 80.3 78.4 72.8 61.6 47.~ 37.4 57.4
Ohio 21.0 20.7 2H.2 31!.5 49.11 59.8 64.4 63.3 56.6 45.9 34.8 25.2 42.4
27.11 27.8 35.11 46.8 58.2 68.0 72.4 70.9 64.7 53.8 41.4 31.3 49.9
Columbia 39.6 42.5 53.7 65.4 74.9 84.1 89.0 87.6 80.'\ 693 54.! 42.4 b).2
Mo. 21.3 23.7 33.1 44.3 53.8 63.4 6/.0 65.5 57.9 46.5 34.1 25.1 44.6
30.5 -,3.1 43.4 54.9 64.4 73.8 78.0 76.6 69.1 57.9 44.1 33.8 54.9
Den', [ 42.9 45.0 51.2 59.9 68.8 80.1 85.7 84.4 76.7 64.9 52.6 44.6 63.1
Colo. 18.6 21.2 27.0 35.6 44.5 53.5 59.5 58.3 49.4 38.5 27.6 20.7 37.9
30.8 33.1 39.1 47.8 56.7 66.8 72.6 71.4 63.1 51.7 40.1 32.7 50.5
Dodge City 41.9 46.4 56.0 66.9 75.2 85.6 91.1 89.8 82.0 69.9 55.8 44.8 67.1
Kans. 18.1 21.7 29.3 40.9 51.1 61.2 66.4 65.1 56.5 43.8 29.9 21.5 42.1
30.0 34.1 42.7 53.9 63.2 73.4 78.8 77.5 69.3 56.9 42.9 33.2 54.6
E~st Lansing 29.8 30.4 40.6 54.2 67.6 77.3 82.3 80.0 72.5 60.6 45.3 33.2 56.1
Mich. 16.0 14.6 23.8 34.0 45.5 55.3 59.4 57.4 50.9 40.4 30.3 20.0 37.3
22.9 22.5 32.2 44.1 56.6 66.3 70.9 68.7 61.7 50.5 37.8 26.6 46.7
EI Paso 57.3 62.4 69.0 77.3 85.5 94.0 93.5 91.7 86.7 77.7 65.7 57.2 76.5
Texas 32.6 36.7 42.4 50.2 58.6 67.3 70.0 68.9 63.1 52.0 39.7 33.4 51.2
45.0 49.6 55.7 63.8 72.1 80.7 81.8 80.3 74:9 64.9 52.7 45.3 63.9
rort Worth 56.4 59.7 68.4 75.7 82.3 91.0 94.4 95.2 88.3 78.6 66.6 57.5 76.2
Tcx~s 36.0 38.4 46.2 54.4 62.6 70.9 74.0 74.3 67.5 57.1 45.9 37.7 55.4
46.2 49.1 57.3 65.1 72.5 81.0 84.2 84.8 77.9 67.9 56.3 47.6 65.8
I' re~no 54.5 61.3 66.4 74.3 82.1 90.9 99.0 97.0 8!1.6 78.8 66.5 55.1 76.3
(,~Iif. 37.7 41.4 44.1 411.1 53.2 59.3 64.8 63.1 58.0 50.7 42.8 38.3 50.1
46.1 51.2 55.3 61.2 67.7 75.1 81.9 80.1 73.6 64.8 54.7 46.7 63.2
(ire"t Falh 31.fi 35.5 40.8 56.1 64.9 70.0 83.4 80.9 70.3 59.5 44.9 36.8 56.2
Mont. 13.3 15.'> 21.0 33.4 42.0 48.3 55.9 53.9 46.1 '38.2, 21.6 20.2 34.7
22.5 25.7 30.9 44.8 53.5 59.2 69.7 67.4 58.2 48.9 36.3 28.5 45.5
(, rcenshoro 50.1 52.0 59.7 69.7 78.8 86.3 87.8 86.3 81.3 71.7 59.4 49.8 69.4
N. (' 30.3 30.1 36.4 45.1 54.7 63.5 66.7 65.4 59.5 -16.6 36.0 2').5 47.0
40.2 41.1 48.1 57.4 66.8 74.9 77.3 75.9 70.4 59.2 47.7 39.7 58.2
"[)II~ton 62.3 65.2 71.7 77.9 84.2 90.3 92.2 92.5 88.2 81.1 70.7 63.7 78.3
Texas 44.9 47.2 53.6 60.1 66.6 72.5 74.4 74.4 70.3 61.5 52.1 46.3 60.3
53.6 56.2 62.7 69.0 75.4 81.4 83.3 83.5 79.3 71.3 61.4 55.0 69.3
Indianapolis 36.5 38.9 48.9 61.2 73.1 82.5 86.9 84.6 77.9 66.0 50.5 39.5 60.9
Ind. 2 1.4 23.1 31.7 41.9 52.8 62.3 66.1 64.0 56.9 45.8 34.0 24.6 43.8
29.0 3 1.0 40.3 51.6 63.0 72.4 76.5 74.3 67.4 55.9 42.3 32.1 52.3
linenln 13.5 37.2 48.7 63.0 72.7 82.8 89.1 86.7 79.0 66.7 50.1 37.6 62.3
Nebr. 14.7 17.9 28.2 41.0 51.2 61.6 66.5 64.5 55.9 43.8 29.9 19.8 41.3
24.1 17.6 38.5 52.0 62.0 72.2 77.8 75.6 67.5 55.3 40.0 28.7 51.8
I iltlc Rock. 50.4 5.l.9 62.6 72.0 79.2 87.5 90.6 89.9 84.2 74.1 61.3 52.2 71.5
Ark. B.9 36.2 43.8 52.9 60.7 68.9 72.0 71.1 64.2 53.6 42.6 35.8 53.0
42.2 45. I 53.2 62.5 70.0 78.2 81.3 80.5 74.2 63.9 52.0 44.0 62.3
I ox Angeles 63.2 M.l 64.8 66.5 68.8 70.7 74.2 74.8 74.9 72.5 70.0 66.4 69.2
('alif. 43.2 4~.0 46.1! 50.7 53.8 57.1 60.5 60.9 59.3 54.9 48.6 45.6 52,2
53.2 54.6 55.1! .58.6 61.3 63.9 67.4 67.8 67.1 63.7 .59.3 5.5.9 60,7
Mlldixon 25.1 111.0 38.(-, 54.2 66,6 76.1 81.3 78.8 70.7 58.5 42.0 29.3 54.1
Wi, 10.3 12.9 23.1! 37.2 48.8 59.0 63.9 61.8 .54.0 42,.5 28.7 16.8 38.3
17.7 20.5 31.2 4.5.7 .57.7 67.6 72.6 70.3 62.4 50.5 35.4 23. t 46.2
(continued)
49
-------
TABLE 3-(Contlnued)
Top Line: Maximum.
Middle Line: Minimum.
Bottom Line: Mean.
Stations Jan Feb Mar Apr May Jun Jut Aug Sep Oct Nov Dee Year
Miami 74.2 74.6 76.6 79.4 82.4 85.4 86.8 87.3 86.0 82.6 77.6 75.2 80.7
Fla. 62.3 61.6 64.5 68.2 71.8 74.9 76.2 76.8 75.8 72.5 66.6 63.2 69.S
68.3 68.1 70.6 73.8 77.1 80.2 81.5 82.1 80.9 77.6 72.1 69.2 75.1
Minneapolis 22.1 25.4 38.1 55.3 67.8 77.4 83.0 80.4 71.7 59.0 40.5 27.0 54.0
Minn. 5.2 8.3 21.6 36.4 48.0 58.3 63.2 60.8 52.3 40.8 25.6 12.3 36.1
13.7 16.9 29.9 45.9 57.9 67.9 73.1 70.6 62.0 49.9 33.0 19.7 45.1
NashviUe 47.8 49.9 59.2 69.3 78.2 86.2 89.1 88.0 82.6 71.9 58.4 49.4 69.2
Tenn. 31.2 32.5 40.2 49.4 58.1 66.8 69.9 68.6 61.9 50.2 39.5 33.0 50.1
39.5 41.2 49.7 59.4 68.2 76.5 79.5 78.3 72.3 61.1 49.0 41.2 59.7
New Orleans 63.0 65.4 71.1 77.0 83.2 88.6 89.7 89.7 86.3 78.8 69.7 63.6 77.2
La. 47.5 49.6 55.1 61.4 68.0 74.0 75.6 75.8 72.9 64.3 54.3 48.5 62.3
55.3 57.5 63.1 69.2 75.6 81.3 82.7 82.8 79.6 71.6 62.0 56.1 69.8
New York 39.2 39.4 48.2 58.9 70.6 79.6 84.5 82.4 76.3 65.9 53.0 41.6 61.6
N. Y. 26.0 25.5 32.9 42.4 52.7 61.9 67.4 65.9 59.6 49.9 39.9 29.4 46.1
32.6 32.5 40.6 50.7 61.7 70.8 76.0 74.2 68.0 57.9 46.5 35.5 53.9
Norfolk 49.8 50.7 57.7 66.4 75.7 83.4 86.8 84.9 79.6 69.8 59.7 51.1 68.0
Va. 34.3 34.4 40.2 48.2 57.8 66.3 70.6 70.2 65.6 55.0 44.0 36.3 51.9
42.1 42.6 49.0 57.3 66.8 74.9 78.7 77.6 72.6 62.4 52.1 43.7 60.0
Oklahoma City 47.4 51.S 61.5 71.0 77.9 87.3 91.9 92.3 85.1 73.8 60.1 49.3 70.8
Okla. 27.8 30.3 38.8 49.3 58.0 67.2 70.9 70.3 63.1 51.7 39.1 30.4 49.7
37.6 40.9 50.2 60.2 68.0 77.3 81.4 81.3 74.1 62.8 49.6 39.9 60.3
Philadelphia 40.6 41.4 49.9 61.0 72.3 80.7 85.0 82.6 76.7 65.9 53.5 43.1 62.7
Pa. 27.0 27.0 34.0 43.4 54.1 63.2 68.6 66.9 60.7 49.9 39.6 30.2 47.1
33.8 34.2 42.0 52.2 63.2 72.0 76.8 74.8 68.7 57.9 46.6 36.7 54.9
Phoenix 64.9 69.1 74.6 83.0 91.6 101.3 103.8 101.7 97.8 86.9 74.9 65.9 84.6
Ariz. 37.9 41.7 46.2 52.5 59.7 68.3 76.9 75.7 68.9 56.0 44.6 38.7 55.6
51.4 55.4 60.4 67.8 75.7 84.8 90.4 88.7 83.4 71.5 59.8 52.3 70.1
Pittsburgh 38.7 39.7 48.8 60.7 72.0 80.2. 84.2 82.1 76.2 64.4 50.5 40.5 61.5
Pa. 23.6 23.5 31.1 41.0 51.6 60.4 64.5 62.8 56.7 45.6 35.4 26.8 43.6
31.2 31.6 40.0 50.9 61.8 70.3 74.4 72.5 66.5 55.0 43.0 33.7 52.6
Portland 44.3 48.7 54.8 61.4 67.3 72.1 78.4 78.0 72.3 62.9 52.3 46.5 61.6
Oreg. 34.4 36.9 40.1 43.6 48.4 53.1 56.8 56.6 52.9 47.5 41.1 37.2 45.7
39.4 42.8 47.5 52.5 57.9 62.6 67.6 67.3 62.6 55.2 46.7 41.9 53.7
Providence 37.5 37.3 46.0 56.5 67.6 76.6 82.0 79.9 73.2 63.2 51.0 40.1 59.2
R.I. 22.2 21.4 29.7 38.6 48.5 57.4 63.6 61.8 54.8 45.2 35.5 25.6 42.0
29.9 29.4 37.9 47.6 58.1 67.0 72.8 70.9 64.0 54.2 43.3 32.9 50.6
Rapid City 35.0 36.3 44.0 56.4 65.8 75.5 84.8 83.4 73.8 61.7 48.2 38.0 58.6
S. Dak. 11.6 13.7 21.5 33.5 43.4 52.9 59.4 57.6 47.8 37.0 25.2 16.0 35.0
23.3 25.0 32.8 45.0 54.6 64.2 72.1 70.5 60.8 49.4 36.7 27.0 46.8
Sacramento 52.4 58.3 63.5 69.6 76.1 84.1 90.0 89.2 84.6 75.4 63.9 53.4 71.7
Calif. 38.8 42.5 45.4 48.1 51.7 56.0 58.2 57.5 56.0 50.7 43.6 39.4 49.0
45.6 60.4 54.5 58.8 63.9 70.0 74.1 73.3 70.3 63.0 53.8 46.5 60.4
Salt Lake City 35.7 41.7 50.6 62.3 71.7 81.4 92.1 89.7 79.5 66.2 49.4 39.5 63.3
Utah 17.0 23.6 30.1 38.1 45.0 52.2 61.5 59.9 49.9 39.9 28.1 22.1 39.0
26.4 32.7 40.4 50.2 58.4 66.8 76.8 74.8 64.7 53.1 38.8 30.8 51.2
San Antonio 62.7 66.3 73.4 79.8 85.4 91.5 94.3 94.9 89.5 81.9 71.0 63.9 79.6
Texas 42.4 45.2 51.5 58.6 65.4 71.4 73.2 73.3 69.1 60.2 50.5 44.1 58.7
52.6 55.8 62.5 69.2 75.4 81.5 83.8 84.1 79.3 71.1 60.8 54.0 69.2
Seatlle 44.7 47.9 52.1 58.1 63.8 68.5 73.7 73.1 67.3 59.1 51.2 46.6 58.8
Wash. 35.8 37.3 39.2 42.8 47.6 51.9 55.1 55.3 52.1 47.2 41.6 38.2 45.3
40.3 42.6 45.7 50.5 55.7 60.2 64.4 64.2 59.7 53.2 46.4 42.4 52.1
St. Louis 40.3 43.5 53.6 65.2 75.1 84.3 88.6 86.8 79.8 68.5 53.7 43.2 65.2
Mo. 24.6 27.0 36.0 47.1 57.2 66.7 71.1 69.1 61.8 50.4 37.7 28.6 48.1
32.5 35.3 44.8 56.2 66.2 75.5 79.9 78.0 70.8 59.5 45.7 35.9 56.7
Tampa 70.5 71.7 76.2 80.7 86.0 89.0 89.5 89.8 88.4 82.9 76.0 71.1 81.0
Fla. 52.5 53.5 57.8 62.1 67.7 72.2 73.9 74.1 72.6 66.3 58.1 53.2 63.7
61.5 62.7 67.0 71.4 76.9 80.6 81.7 82.0 80.5 74.6 67.1 62.2 72.4
Washiogton 45.5 47.2 55.4 66.2 75.4 83.6 87.1 84.7 78.7 69.1 56.5 45.3 66.2
D.C. 30.2 )
-------
APPENDIX VI 51
TUU """"'yerap Atmoepla.rlc Temperature, D~ F8hreohelt, C._cia
Top Une: Maximum.
Middle Une: Minimum.
Bottom Une: Mean.
StatloQl Ian Peb Mar Apr May lun lul Aug Sep Oct Nov Dee Year
Calaary 24 18 37 '3 63 69 76 74 64 54 38 29 51
AltL 1 6 14 27 36 43 47 45 37 29 17 9 26
13 17 26 40 50 56 62 60 51 42 28 19 38
Edmonton IS .
22 34 52 64 70 74 72 62 52 34 21 48
Alta. -4 1 12 28 38 45 49 47 38 30 16 5 25
6 11 23 40 51 '8 62 59 50 41 25 13 37
Fort William 17 20 31 44 56 67 74 71 62 50 34 22 46
Ollt. -4 -2 10 26 37 47 52 49 44 34 19 5 27
7 9 20 35 47 57 63 60 53 42 27 14 36
Halifax 32 31 38 47 58 68 74 74 67 57 46 35 52
N. S. 15 l' 23 31 40 48 55 56 50 41 32 21 36
24 23 30 39 49 58 65 65 59 49 39 28 44
~ :If\\:oops 28 34 48 62 71 77 84 81 70 56 41 32 57
..C. 16 20 29 38 46 52 56 55 47 39 30 22 37
22 27 38 SO 58 64 70 68 58 48 36 27 47
London 29 )9 39 54 67 77 81 79 72 58 44 33 55
Onl. IS 12 22 33 44 53 58 55 SO 39 30 20 36
22 21 30 44 55 65 69 67 61 49 37 26 46
Montreal 22 23 33 50 64 74 78 76 67 54 39 26 50
P. Q. 6 8 19 34 46 56 61 59 51 40 28 13 35
14 IS 26 42 56 65 70 67 59 47 33 20 43
Moose law 13 18 30 52 66 73 80 78 66 52 34 21 49
Sask. -5 -2 10 27 38 48 52 49 40 28 IS 2 25
4 8 20 40 52 61 66 63 53 40 24 12 37
Ottawa 21 22 33 50 66 76 81 77 68 54 38 24 51
Ont. 3 4 16 31 44 54 58 55 48 37 26 9 32
12 24 24 41 55 65 70 66 58 46 32 17 42
Quebec 18 20 31 44 61 72 76 73 64 51 36 22 47
P. Q. 22 4 15 29 41 52 57 54 48 37 24 9 31
10 12 23 37 51 62 57 64 56 44 30 16 39
Regina 10 13 27 50 65 73 79 77 65 52 32 16 46
Sask. -11 -9 6 26 37 47 51 48 38 27 11 -1 22
-1 2 16 38 51 60 65 62 51 39 21 8 3'4
SI. John 28 28 36 46 57 64 68 68 63 54 42 31 49
N. B. 11 12 21 31 41 49 54 54 49 40 30 17 3f1
19 20 28 39 49 56 61 61 56 47 36 24 41
St. John's 30 28 33 41 51 61 69 68 61 53 43 35 48
Nfld. 18 16 22 29 35 44 51 54 47 \ 40 32 24 34
24 22 28 35 43 52 50 61 54 46 38 30 41
Saskatoon 9 13 27 49 64 71 77 75 63 51 31 16 46
Sask. -11 -8 6 26 38 48 52 48 38 27 12 -2 23
-1 3 17 37 51 60 65 62 51 39 22 7 34
Toronto 30 30 37 50 63 73 79 77 69 S6 43 33 53
Ont. 16 15 23 34 44 54 59 58 51 40 31 21 37
23 22 30 42 53 63 69 67 60 48 37 27 45
VaOl:ollver 40 44 50 57 63 69 74 72 66 56 48 42 57
B. C. 32 33 36 40 46 SO 54 53 49 44 38 35 43
36 39 43 48 54 60 64 \ 63 t, 57 SO 43 39 49
Windsor 31 32 41 55 68 77 82 80 73 61 46 34 57
Ont. 16 16 24 36 46 60 61 60 53 42 31 21 39
24 24 33 46 57 68 72 70 63 51 38 27 48
Winnipeg 7 12 27 48 65 74 79 76 65 51 30 15 46
Man. -13 -9 5 27 40 50 55 52 43 31 14 -3 24
- J 2 16 38 52 62 67 64 54 41 22 6 35
Sourc~: Oimatic sunlmariel for &elected stations in Canada; Meteoroloaical Division of the Department of Transport, Ottawa, Onto
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5~ EVAPORATION LoSs--CAUSES AND CONTROL
TABLE S--Averalo Wind Speed in MUoll per Hour, United Statell
Stations Jan Feb Mar Apr May JUD Jut Aug Sep Oct Nov Dec Year
Albuquerque 9.8 11.3 9.9 8.8 8.1 7.7 7.8 6.9 8.8
N. Mex. 6.6 8.6 9.3 10.2
Atlanta 10.6
Ga. 11.5 11.9 11.8 10.8 9.3 8.2 7.8 7.4 8.3 9.4 11.1 9.8
Binghamton 4.8 5.5 6.4 6.6 6.0
N. Y. 6.9 7.1 7.2 6.9 5.9 5.2 4.7 4.6
Bismarck
N. Dak. 10.1 10.3 11.4 12.9 12.5 11.9 9.8 9.9 10.5 10.2 10.6 9.4 10.8
Boston
Mass. 12.6 13.2 13.2 12.9 11.4 11.0 10.0 9.9 10.7 11.3 12.3 12.6 11.8
Casper 12.3 15.0 17.0 13.6
Wyo. 18.2 17.0 14.8 12.8 11.5 12.1 10.4 11.1 11.1
Charleston
S. C. 9.9 10.6 11.0 10.9 10.3 9.8 9.4 9.5 10.2 10.2 9.9 9.7 10.1
Chicago
111. 11.7 11.8 12.4 12.0 10.5 9.6 8.7 8.7 9.5 10.2 11.8 11.3 10.7
Cleveland
Ohio 13.0 12.5 13.3 11.2 9.6 9.0 8.1 8.5 9.8 10.0 10.7 11.7 10.6
Colul","ia
Mo. 8.7 9.4 10.1 9.7 7.7 6.7 6.0 6.0 6.5 7.1 8.7 8.6 7.9
Denver
Colo. 7.7 7.8 8.3 8.4 7.8 7.5 7.0 6.7 6.8 7.0 7.4 7.3 7.5
Dodge City
Kans. 10.9 11.4 13.2 13.9 13.0 12.6 11.2 10.7 11.8 11.5 10.9 10.8 11.8
East Lansing
Mich. 11.0 11.1 11.4 11.1 9.2 8.1 7.4 7.1 8.1 8.9 10.6 10.4 9.5
EI Paso
Texas 8.7 9.9 11.3 11.4 10.7 9.5 8.6 8.0 8.0 8.1 8.4 8.7 9.3
Fort Wortb
Texas 10.9 11.4 12.5 12.4 11.2 11.0 9.7 9.4 9.3 9.6 10.3 10.3 10.7
Fresno
Calif. 5.4 5.8 6.4 7.4 8.3 8.6 7.8 7.3 6.6 5.6 4.9 5.0 6.6
Great Falls
Mont. 17.6 16.6 14.3 14.3 12.5 12.6 11.2 11.1 12.2 14.5 16.2 17.6 14.2
Greensboro
N. C'. 8.3 8.7 9.5 9.2 8.0 7.2 6.7 6.4 7.0 7.3 7.7 7.6 7.8
Houston
Texas 10.6 10.9 11.6 11.6 10.6 9.5 8.4 8.4 8.8 9.5 10.3 10.3 10.0
Indianapolis
Ind. 11.4 11.5 I\.9 11.5 10.4 9.4 8.7 8.3 9.1 9.8 11.0 11.0 10.3
Lincoln
Nebr. 10.4 10.8 12.1 12.2 10.8 10.1 9.2 9.1 9.8 10.2 10.5 10.1 10.4
Little Rock
Ark. 8.3 8.8 8.8 8.9 7.6 6.7 6.3 6.0 6.2 6.6 7.6 8.0 7.5
Los Angeles
Calif. 5.9 6.1 6.8 6.4 6.7 6.5 6.0 5.9 5.3 5.1 5.0 5.6 5.9
Madison
Wis. 11.7 1 \.8 13.3 12.9 11.1 10.2 8.8 8.0 9.7 10.0 11.9 11.0 10.9
Miami
Fla. 13.6 13.5 14.3 14.0 12.2 11.0 10.5 10.3 12.2 13.2 12.8 13.0 12.6
Minneapolis
Minn. 11.2 11.4 12.2 12.6 11.8 10.6 9.7 9.7 10.9 11.4 11.5 11.1 11.2
Nashville
Tenn. 9.6 9.9 10.5 10.2 8.5 7.7 7.0 6.7 7.2 7.6 9.0 9.2 8.6
New Orleans
La. 8.4 8.7 8.8 8.4 7.5 6.8 6.5 6.4 7.4 7.7 8.0 8.2 7.7
New York
N. Y. 16.5 17.0 17.3 15.9 13.6 12.9 12.1 11.7 12.5 14.0 15.8 16.3 14.6
Norfolk
Va. 11.9 12.1 12.8 12.2 10.9 10.1 9.6 9.5 10.0 10.7 11.2 11.3 11.0
Oklnhoma City
Okla. 16.5 15.7 17.2 17.0 15.1 15.2 12.1 11.4 12.6 13.6 13.8 14.8 14.6
Philadelphia
Pa. 10.9 11.3 11.8 11.3 10.0 9.3 8.7 8.4 8.8 9.7 10.4 .10.5 10.1
Phoenix
Ariz. 4.3 4.9 5.7 D 5.8 5.6 5.8 5.2 4.8 4.4 4.1 4.0 5.0
Pittsburgh
Pa. 11.6 12.0 12.5 1 \.8 10.0 9.2 8.5 8.1 8.3 9.6 11.4 11.6 10.4
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ApPENDIX VI 53
TABLE S-(Contlnaed)
StatioOl Jan Peb Mar Apr May Jun Jut Aug Scp Oct Nov Dee Year
Portland
Oreg. 7.5 7.3 7.2 6.9 6.8 6.6 6.8 6.3 6.2 6.0 6.9 7.4 6.8
Providence
R. I. 11.8 12.1 12.5 12.1 10.7 10.0 9.1 8.8 9.4 10.3 11.0 11.4 10.8
Rapid City
S. Dak. 12.6 13.1 13.9 15.1 14.0 12.4 11.4 11.9 12.8 12.4 13.1 12.1 12.9
Sacramento
Calif. 7.1 7.7 8.0 8.2 8.6 8.6 8.3 7.8 7.0 6.4 6.1 6.7 7.5
Salt Lake City
Utah 7.6 8.0 9.1 9.4 9.5 9.5 9.5 9.7 9.1 8.6 7.7 7.4 8.8
San Antonio
Texas 8.4 9.1 9.6 9.5 9.0 8.6 7.9 7.4 7.5 7.6 8.1 8.0 8.4
Seattle
Wash. 10.3 9.8 10.1 9.4 8.9 8.4 7.9 7.3 7.5 8.4 9.4 10.5 9.0
51. Louis
Mo. 11.9 12.0 12.6 12.1 11.0 10.1 9.3 9.0 9.8 10.6 11.8 11.6 11.0
Tampa
I':" 8.4 8.9 9.1 8.9 8.3 7.6 7.1 7.0 7.9 8.7 8.5 8.2 8.2
Wa~hington
D. C. 10.9 11.3 12.2 11.4 9.4 9.3 8.5 8.2 8.6 8.9 9.5 10.0 9.9
TABLE 6--Avera.e Wind Speed In Mile. per Hour, Canada
Sf.lrions Jan Fcb Mar Apr May Jun Jul Aug Sep Oct Nov Dec Year
Calgary
Alta. 6.8 6.8 7.6 8.2 8.4 7.8 6.8 6.9 7.1 7.1 6.9 7.3 7.3
Edmonton
Alta. 7.2 8.3 9.3 10.6 9.7 9.7 8.6 8.3 8.4 8.7 7.9 7.4 8.7
Fort William
Onto 7.9 8.3 8.9 8.8 8.7 7.9 6.8 7.1 7.9 8.9 8.8 8.3 8.2
Halifax
N. S. 9.1 10.3 10.2 8.8 7.6 7.3 6.3 7.7 7.7 8.5 9.1 9.5 8.4
Kamlonps
B. C.
I.ondon
Onl. 10.9 11.3 11.5 11.1 9.2 7.6 6.3 5.9 7.4 8.9 10.5 10.5 9.3
Montrcal
P. Q. 12.4 12.7 12.7 12.4 11.3 10.5 9.6 9.5 10.3 11.~ 10.9 11.9 11.3
Moose Jaw
Sask.
Ottawa
Onl. 8.0 7.4 7.8 8.4 7.6 6.5 5.7 5.9 6.2 7.3 8.2 7.7 7.2
Quebec
P. Q. 12.7 12.6 12.7 12.1 12.1 9.9 8.7 8.3 9.2 10.4 .11.2 11.8 11.0
RCAina
Sa,"- 12.0 12.1 13.2 13.9 14.0 13.4 11.4 12.3 12.6 12.9 13.0 12.1 12.7
St. John
N. II. 14.2 13.4 13.2 11.9 9.9 8.7 7.6 7.5 9.1 11.6 12.3 13.9 11.1
St. John's
Nfld. 12.3 13.1 11.4 11.1 9.6 9.3 9.1 9.8 9.8 10.9 11.5 12.4 10.9
Saskatoon
Sask. 9.5 9.3 11.1 12.6 13.0 11.4 10.2 10.6 10.2 11.7 10.8 10.2 10.9
.
Toronto
Ont. 14.7 13.6 13.8 12.7 10.2 8.8 8.0 8.4 9.3 10.6 12.8 13.9 11.4
Vancouvcr
B. C. 3.7 4.0 4.4 4.5 4.3 4.0 3.8 3.4 3.4 3.3 3.4 4.8 3.9
Windsor
Oot. 12.1 13.4 13.7 12.4 9.6 7.2 7.5 7.0 8.1 9.7 11.5 11.4 10.3
Winnipeg 11.8 11.4
Man. 12.3 13.6 13.3 12.4 10.8 11.4 12.7 13.2 13.1 12.0 12.3
SOl"C~: Clim:lIie summaries for selected stations in Canada; Meteorological Division of the Department of Transport, Ottawa, Ont.
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54 EVAPORATION LoSs--CAUSES AND CONTROL
_.- -- --- --- -----
TABLE 1-Aven,e Preelplt8t1on In Inche., United Stale.
Statio.. Ian Pcb Mar Apr May Jun Jul Au. Sep Oct Nov Dec Year
Albuquerque 0.70 0.61 1.44 1.28 0.92 0.75 0."5 0.41 8.27
N.Mex. 0.37 0.34 0.40 0.60
Atlanta
08. 4.71 4.68 5.49 3.91 3.49 3.85 4.66 4.15 3.16 2.50 3.09 4.63 48.32
Binghamton 2.80 2.46 2.36
N. Y. 2.34 2.21 2.85 2.81 3.47 3.34 3.64 3.43 3.14 34.85
Bismarck
N. Oak. 0.46 0.46 0.92 1.49 2.22 3.39 2.28 1.82 1.30 0.95 0.55 0.52 16.36
Boston
Mass. 3.61 3.26 3.81 3.54 3.32 3.14 3.22 3.62 3.15 3.22 3.76 3.41 41.06
Casper
Wyo. 0.53 0.48 0.88 1.42 2.07 1.22 1.02 0.61 0.93 0.94 0.64 0.43 11.17
Charleston
S.C. 2.81 3.20 3.39 2.73 3.21 4.62 7.19 6.50 5.19 3.12 2.23 2.85 47.04
Chicago
111. 1.94 1.87 2.75 2.88 3.56 3.62 3.22 3.14 3.11 2.64 2.36 2.03 33.12
Cleveland
Ohic 2.62 2.39 2.89 2.65 3.07 3.23 3.36 2.88 3.16 2.65 2.58 2.41 33.119
Columbia
Mo. 1.92 1.80 2.95 3.75 4.75 4.83 3.28 3.97 4.39 2.86 2.32 1.83 38.65
Denver
Colo. 0.45 0.55 1.09 2.01 2.31 1.38 1.S6 1.38 0.99 0.99 0.64 0.63 13.98
Doose City
Kans. 0.44 0.73 0.94 1.98 2.96 3.21 2.86 2.61 1.72 1.40 0.79 0.59 :'O.'!4
East Lansinl
Mich. 1.87 1.81 2.50 2.82 3.61 3.43 2.57 2.82 2.92 2.47 2.26 2.03 31.11
EI Paso
Texas 0.45 0.40 0.33 0.29 0.36 0.62 1.70 1.S4 1.16 0.82 0.46 0.51 8.64
Fort Worth
Tc){as 1.83 2.00 2.24 3.81 4.69 3.01 2.14 2.24 2.58 2.72 2.28 2.00 31.54
Fresno
Calif. 1.72 1.S1 1.63 0.91 0.37 0.11 0.01 0.01 0.15 0.56 0.89 U7 9.44
Great Falls
Mont. 0.60 0.72 0.94 0.96 2.38 3.26 1.23 1.10 1.42 0.74 0.69 0.60 14.64
Greensboro
N.C. 3.39 3.15 3.83 3.23 3.43 3.69 4.68 4.54 3.45 2.57 2.84 3.27 42.07
Houston
Texas 3.63 2.96 3.02 3.48 4.73 4.20 4.26 3.71 3.88 3.54 3.76 4.27 45.44
Indianapolis
Ind. 3.09 2.57 3.90 3.60 3.85 4.14 3.66 3.27 3.22 2.69 3.19 2.86 40.04
Lincoln
Nebr. 0.71 0.98 1.35 2.52 3.83 4.33 3.57 3.48 2.83 1.83 1.22 0.84 27.49
lillie Rock
Ark. 4.96 3.89 4.67 5.00 4.85 3.56 3.32 3.34 3.05 2.86 4.07 4.15 47.72
Los Angeles
Calif. 2.17 2.49 1.94 0.95 0.25 0.06 T 0.02 0.22 0.39 1.11 2.47 12.07
Madison
Wis. 1.54 1.40 2.07 2.54 3.53 3.97 3.71 3.19 3.63 2.25 1.89 1.S7 31.29
Miami
Fla. 2.11 1.88 2.29 3.52 6.45 6.71 5.44 5.73 8.30 11.16 2.93 1.74 55.26
Minneapolia
Minn. 0.82 0.87 1.51 2.11 3.43 4.28 3.44 3.13 3.02 1.96 1.37 0.91 26.85
NII~hvilie
Tenn. 4.98 4.14 5.16 4.13 3.77 3.79 3.98 3.38 3.19 2..H 3.42 4.06 46.44
Ncw Orlclln.
LII. 4.55 4.46 5.50 5.33 4.77 5.78 6.79 5.96 5.39 3.37 3.74 4.78 60.42
New York
N. Y. 3.53 3.42 3.85 3.41 3.46 3.44 4.31 4.38 3.67 3.50 3.22 3.39 43.58
Norfolk
Va. 3.19 3.33 3.74 3.32 3.72 4.13 5.82 5.42 3.67 2.98 1.62 3.19 45.13
Oklahoma City
Okla. 1.35 1.21 2.14 3.36 5.05 3.83 2.66 2.73 2.95 2.72 2.06 1.S2 31.58
Philadelphia
PH. 3.36 3.15 3.53 3.30 3.52 3.54 4.20 4.65 3.29 2.81 3.09 3.15 41.59
Phocni){
Ariz. 0.82 0.78 0.66 0.40 0.13 0.08 1.02 1.07 0.78 0.41 0.65 0.85 7.65
Pitl~burgh
Pa. 2.97 2.48 3.25 3.04 3.28 3.82 4.00 3.21 2.56 2.53 2.34 2.73 36.21
-------
ApPENDIX VI SS
TABLE 7-(Contlnued)
Statloll.l Jan Fcb Mat Apr May Jun Jul Aug Scp Oct Nov Dee Year
Portlaud
Orcg. 6.36 5.23 4.54 2.78 2.15 1.59 0.53 0.64 1.82 3.36 6.23 7.02 42.25
Providence
R.I. 3.69 3.04 3.57 3.47 3.13 2.94 3.06 3.65 3.19 2.83 3.51 3.56 39.64
Rapid City
S. Dak. 0.43 Q.41 1.01 1.91 3.29 3.37 2.36 1.67 1.29 1.06 0.63 0.55 17.9a
Sacramcnto
Cali f 3..5.5 3.00 2.64 1.45 0.70 0.13 0.02 T 0.22 0.83 1.85 3.64 18.03
Salt Lake City
Utah 1.31 1.16 1.60 1.72 1.30 0.97 0.66 0.93 0.64 1.25 1.27 1.23 14.04
San Antonio
Texas 1..56 1.56 1.75 3.06 3.22 2.79 2.0.5 2.24 3.00 2.19 1.72 1.74 26.88
Seattle
Wash. 4.91 3.8.5 3.12 2.22 1.78 1.36 0.64 0.71 1.70 2.91 4.87 5.49 33..56
St. Louis
Mo. 2.30 2.42 3.49 3.74 4.36 4.38 3.43 3.54 3.21 2.86 2.79 2.44 38.96
T...npa
Tis. 2.26 1.63 2.72 2.26 2.95 7.49 8.01 7.98 6.76 2.81 1.63 2.02 49.52
.rashln8ton
D. C. 3.07 2.08 3.44 2.93 5.12 3.49 4.40 4.80 3..51 3.01 3.33 3.02 42.20
T = Trace.
TABLE 8--AverDle Precipitation In Inehea, Canada
Statlonl Jan Fcb Mar Apr May Jun Jul Aug Scp Oct Nov Dee Ycar
Calaary
Alta. .51 .55 .84 .99 2.34 3.14 2.51 2.29 1..50 .69 .72 ..57 16.65
Edmonton
Alta. .8& .64 .76 .88 1.85 3.06 3.32 2.35 1.33 .75 .75 .81 17.38
Fort William
Onto .91 .76 .95 1.49 2.11 2.81 3..56 2.78 3.37 2.45 1..52 .95 23.66
Halifax
N. S. 5.40 4.35 4.85 4.54 4.14 4.04 3.79 4.38 4.13 5.42 5.31 5.39 55.74
Kamloops
B. C. 1.04 .74 .38 .40 .88 1.29 .99 1.07 .82 .68 .86 1.05 10.20
London
Ont. 3.97 3.45 2.81 2.87 2.81 3.11 3.21 2.80 2.96 2.91 3.74 3.53 38.17
Montreal
P.Q. 3.76 3.02 3.46 2.60 3.14 3.43 3.74 3.45 3.65 3.42 3.55 3.58 4~.80
Moose Jaw
Sask. .68 .50 .69 .75 1.92 2.86 1.97 1.86 1.25 .91 .64 .68 14.71
Ottawa
Ont. 2.93 2.17 2.77 2.70 2.47 3.52 3.39 2.56 3.23 2.93 2.98 2.58 34.23
Quebec
P. Q. 3.45 2.74 3.02 2.35 3.15 3.68 4.02 3.98 3.60 3.41 3.23 3.22 39.85
Regina
Sask. .51 .35 .67 .74 1.84 3.25 2.38 1.76 1.32 .86 .60 .42 14.70
St. John
N. n. 4.28 3.05 3.61 3.22 3.13 3.15 3.03 3.61 3.53 4.01 3.81 3.83 42.26
St. John's
NfW. 5.31 5.D 4.64 3.77 3.85 3.13 3.14 3.97 3.73 4.76 5.71 5.95 53.09
Saskatoon
Sask. .87 .50 .66 .72 1.42 2.57 2.41 1.94 1.46 .88 .51 .61 14.55
Toronto
Ont. 2.71 2.43 2.58 2.48 2.91 2.67 2.95 2.73 2.90 2.43 2.76 2.63 32.18
Vancouver
n. C. 8.57 5.79 5.03 3.34 2.84 2.45 1.22 1.69 3.63 5.78 8.28 8.76 57.38
Windsor
Ont. 2.31 2.16 2.42 2.24 3.08 3.35 3.42 2.69 2.59 2.17 2.45 2.24 31.12
Winnipeg .1\6
Man. .92 1.19 1.37 2.26 3.15 3.08 2.45 2.35 1.49 1.12 .95 21.19
SOIU(": Climatic ,,,",mafiC' for selected stations in Canada; Meteor%llieal Division of (he Department of Transport, Ottawa, Onto
-------
56
EVAPORATION LOSS-CAUSES AND CONTROL
IS"
Note: Figures show maximum snow accumulation under most severe conditions.
Area A: Oil temperature seldom drops below freezing, improbable to obtain 20 in. of .accumulated snow. Winter maintenance
rarely required.
Area B: AlthouSh oil temperature occasionally drops below freezing, improbable to obtain 20 in. of accumulated snow. Winter
maintenance rarely required.
Area C: Oil temperature occasionally drops below freezing, snow accumulation can exceed 20 in. During most severe condi-
tions, winter maintenance occasionally required.
Area 0: Oil temperallire frequently below freezing, snow accumulations can exceed 30 in. Snow removal and winter maintenance
occasionally required. In most severe areas, vapor-balancing structures may be preferable.
Source: Data from the U.S. Weather Bureau.
FIG. I-Snow and Temperature Mop of the' United Stote8.
-------
ApPENDIX VI
57
----- ----- --- -----------.-
TABLE 9-Avera.e Soowf.U 10 loche., Ceoada
Slat/ons Jan Feb Mar Apr May JUD Jul Aug Sep Oet Nov Dee Year
Calgary
AHa. 5.0 5.4 8.1 6.4 5.2 0.3 T 0.1 2.6 4.2 7.1 5.6 50.0
Edmonton
Alt". 8.3 6.3 7.0 4.1 1.9 T T 0.9 3.5 6.8 7.6 46.4
Fort William
Ont. 8.9 7.1 8.0 3.8 0.5 T 1.2 5.9 7.5 42.9
Halifax
N. ~,. 18.9 18.8 11.9 5.7 0.1 0.2 2.7 1~.5 70.8
" m/oops
n. c. 9.5 6.0 1.5 0.1 T 0.5 4.7 8.6 30.9
London
Onto 23.3 22.3 11.3 3.8 0.1 T 0.9 10.8 19.1 91.6
Montreal
P. Q. 27.7 23.3 20.1 5.5 0.1 T 0.9 10.9 23.8 112.3
Moose Jaw
Sask. 6.7 4.9 6.3 2.7 0.7 T 0.9 2.6 5.0 6.2 36.0
Ottawa
Ont. 21.5 17.3 14.4 4.4 T 0.8 6.4 17.2 82.0
Qllchec
P. Q. 29.3 23.1 20.8 8.7 0.5 T 1.8 14.4 25.1 123.7
Rc!:ina
Sask. 4.7 3.4 5.4 3.0 0.6 0.1 0.6 2.3 4.8 3.9 28.8
51. John
N. R. 18.8 17.2 11.5 5.4 0.1 0.2 5.1 12.8 71.1
51. John's
Nfld.
Saskatoon
Sask. 8.7 5.0 6.2 2.5 0.3 0.8 2.6 5.0 6.1 37.2
Toronto .
Onto 16.0 15.3 10.7 2.8 0.1 T T 0.4 4.2 12.4 61.9
Vancouver
8. C. 11.5 6.4 2.7 0.3 0.1 2.1 5.7 28.8
Windsor
Ont. 12.4 10.4 7.8 1.8 T 0.2 2.9 8.9 44.4
Winnipeg
Man. 9.1 8.4 10.0 3.9 1.1 T 0.1 2.9 9.0 9.1 53.6
Sou,c~; Meteoroloaicnl Division of the Deparlmcnt of Trnnsport. Ottawa. Onto
T Trace.
-------
APPENDIX VII-COMMI'ITEE MEMBERSHIP
Committee on Evaporation Lo88, 1956-1958
Memben
J. H. McClintock (Chairman). . . Esso Standard Oil Co.. . . . . . . . . . . . . . . . . . NeW York, N. Y.
E. L. Hoffman (Vice Chairman) . .. Socony Mobil Oil Co., Inc.. .. .. .. . . . . New York, N. Y.
E. O. Mattocks (Secretary) .. ...... . American Petroleum Institute. . . . .. .. .... New York, N. Y.
E. M. Beschwitz. . . . . . . . . . . . . ., ...... Gulf Oil Corp.. . . .. ... . ... Pitt.sburgh, Pa.
J. H. Brown. . . . . . . . . . Tidewater Oil Co.. . New York, N. Y.
W. H. Creel. . ... . . .. "" . . . Phillips Petroleum Co... . ....., . . . . . . Bartlesville, Okla.
S. H. Dowdell... . . . . . . . . . . . The British American Oil Co. Limited. Toronto, Ont., Canada
P. E. Frank. ..... . . . . Sinclair Refining Co.. . . .. . New York, N. Y.
T. C. Frick. . . . . . .. Tbe Atlantic Refining Co... . . . Dallas, Texas
J. P. Hammond .. .. . Amerada Petroleum Corp.. . . Tulsa, Okla.
D. E. Hanson. . Sinclair Refining Co.. . .. . New York, N. Y.
H. M. Hart . Standard Oil Co. (Indiana). . Whiting, Ind.
R. W. Hill . . . . . . Pan American Petroleum Corp.. . Tulsa, Okla.
Franc!:> Horton. ... The Texas Co., . New York, N. Y.
F. P II win. . ..... . . . . . . . . . . Imperial Oil Limited Toronto, Ont., Canada
A. W. Jasek. . .. """"'" Humble Pipe Line Co. . ,Houston, Texas
O. W. Johnson. .. . .. . .. . ...,. Standard Oil Co. of California. . San Francisco, Calif.
K. G. Krech .. .......... . The Atlantic Refining Co.. . . Philadelphia, Pa.
E. P. Kropp .. ........ .'The Standard Oil Co. (Ohio) . Cleveland, Ohio
R. T. Mapston, . . . .. """ .. ... Richfield Oil Corp. Wilmington, Calif.
H. S. Mount . . Sun Oil Co. . Philadelphia. Pa.
K. G. Oswald. . . . . . . .. ..... . The Pure Oil Co.. Chicago, Ill.
H. C. Packard. Shell Oil Co. . New York, N. Y.
E. O. Perkins The Texas Co.. . New York, N. Y.
A. B. Stevens. General Petroleum Corp.. Torrance, Calif.
E. F. Wagner. Tbe Atlantic Refining Co.. . Philadelphia, Pa.
L. S. Wrightsman. Humble Pipe Line Co.. . Houston, Texas
Subcommittee I-Methods of Testing, 1956.1958
Memben
O. W. Johnson (Chairman)
J. A. Arnold.
J. M. Dempster
(alternate to E. G. Ellerbrake)
E. G. Ellerbrake,
George Entwistle
H. M. Hart
T. W. Legatski
D. Ray Miley
George Rezanka
J. R. Spencer
G. E. C. Wear
A...ociale Member.
F. W. Homer.
L. V. Larsen
Member.
A. B. Stevens (Chairman)
Otto Gerbes (Secretary)
O. C. Bridgeman.
D. E. Bruce.
O. W. Johnson. . .
R. W. Martz.
C. C. Miller
Standard Oil Co. of California.
The Standard Oil Co. (Ohio) .
The Standard Oil Co. (Ohio)
Sohio Pipe Line Co. .
Sinclair Research Laboratories, Inc..
Standard Oil Co. (Indiana).
Phillips Petroleum Co..
Sun Oil Co.
Sinclair Refining Co..
Continental Oil Co. .
Esso Research and Engineering Co.
. Cleveland, Ohio
. St. Louis, Mo.
. Harvey, Ill.
Whiting. Ind.
. Bartlesvillc, Okla.
Toledo, Ohio
. East Chicago, Ind.
. Ponca City, Okla.
. Linden, N. J.
. San Francisco, Calif.
Cleveland, Ohio
General American Transportation Corp.
Chicago Bridge and Iron Co. .
Subcommittee "-Correlations, 1956.1958
. Chicago, Ill.
. New York, N. Y.
. . . General Petroleum Corp. ,
. . . . . Humble Oil and Refining Co..
. ..... ....... Phillips Petroleum Co..
. . . . . . . . . . . . . . Standard Oil Co. (Indiana)
. .. . . . . . . . . . . . . . , ,."Standard Oil Co. of California
. .. .............. Esso Standard Oil Co.. .
. . . . . . . The Atlantic Refining Co.
SR
Torrance, Calif.
. Bay town, Texas
. Bartlesville, Okla.
Whiting, Ind.
. San Francisco, Calif.
. New York, N. Y.
Dallas, Texas
-------
SubeolJ1lllittee D--Continued
Allociale ./Kember.
T. D. Mueller
N. A. Pierson
I. L. Wissmiller
Graver Tank and Manufacturing Co. .
General American Transportation Corp. .
Chicago Bridge and Iron Co.
IIJ-f'ield Test Program Development,
Shell Oil Co.
. Sohio Pipe Line Co. .
Phillips Petroleum Co..
Cities Service Pipeline Co..
Suhcommittee
Meml,erll
H. C. Packard (Chairman)
E. G. Ellerbrake (Secretary)
K. C. Bouenberg
J. E. Chaffin
J. M. Dcmpster
(altem;)lc to E. G. Ellerbrake)
I. 1'. Frit/.
1-1. M. H,lIt
R. W. Hill
Francis Ilort,)'1
F. P. Irwin
F. S. I.e('
S. B. I isle
R. I. Mculeners
D. Ray Miley
s. H. Pope
A. E. Straub
The Stan ciaI'd Oil Co. (Ohio).
Sinclair Refining Co..
Standard Oil Co. (Indiana)
Pan American Petroleum Corp.
The Tcx...s Co.
Imperial Oil Limited
Shell Oil Co. of Canada, Ltd..
Sohio Petroleum Co.
American Oil Co.
Sun Oil Co.
Gulf Oil Corp. .
Cities Service Oil Co. .
Auocitlle Member.
E. A. Barton
R. W. Bouley
H. V Dwight
A. Fino
L V. Larsen
(alternate to I. L. WissmJler)
W. 1(. Lewis
F. V. L~'ng
N. M. Wi'icman
I. I. \Vi.;smilicr
Nash Engineering Co.
Graver Tank and Manufacturing Co.
The B. F. Goodrich Co. .
Hammond Iron Works
Meru/lf 1'S
H. M. lI;n ( (Chairman)
E P. Kropp (Jlice Chairman)
P D. BakCi
S. I f. Dowdell
P. E. Frank
D. E I !;IIISOi1
F. [ I Jolfman
A. W. J:lsck
K. G. Krech
IJ. S. M\llInt
O. I.. NeurnbcfI..;cr
r: O. Perkins'
I-J. F. Simonson
E. F Wagner
I.. S Wrir.htsman
.'
.1uorinll' Mrmben
W. J; Bland
I. I.; Boberg
" 11.. I IIlTIm;u
,,/ J. M Suardi
J. (' Thompson
Chicago Bridge and Iron Co.
Massachusetts Institute of Technology.
Vapor Recovery Systems Co.
General American Transportation Corp.
Chicago Bridge and Iron Co.
Subcommittee IV-Publications, 1956.1958
Standard Oil Cu. (Indiana)
The Standard Oil Co. (Ohio)
The Carlcr Oil Co.
The British American Oil Co. Limited
Sinclair Relining Co.
Sinclair Refining Co.
Sowny Mobil Oil Co., Inc.
Humble Pipe l.ine Co.
The Atlantic Rcfining Co.
Sun OiJ ('0.
Shell Oil Co.
The Texas Co.
Phillips Petroleulll Co.
The Atlantic Refining Co..
Humble Pipe Line Co..
Mc(iraw-Ilill Puhlishing Co., Inc.
Chicago Bridge and Jron Co.
Graver Tank ...nd Manufacturing Co.
nraver Tank and Manur...cturing Co.
General American Transportation Corp.
.1M ...b )IJr}fj
1M ./.," I'll..'
r,C ~I'" 19,'0
1M M.l' J')/I
'9
East Chicago, Ind.
Chicago, Ill.
Chicago, Ill.
1956.1958
New York, N. Y.
. St. Louis, Mo.
. Bartlesville, Okla.
. Bartlesville, Okla.
Cleveland, Ohio
Marcus Hook, Pa.
Whiting, Ind.
Tulsa, Okla.
New York, N. Y.
Toronto, Ont., Canada
Toronto, Ont., Canada
Oklahoma City, Okla.
. New York, N. Y.
Toledo, Ohio
. Houston, Texas
. Bartlesville, Okla.
Cleveland, Ohio
" East Chicago, Ind.
. Akron, Ohio
Warren, Pa.
. New York, N. Y.
Cambridge, Mass.
. Compton, Calif.
Chicago. IJI.
Chicago, 111.
Whiting, Ind.
Cleveland, 0:';0
Tulsa, OkJa.
Toronto, Onl., C...n...da
New York, N. Y.
. New York, N. Y.
. New York, N. Y.
HOll5ton, Texas
Philadelphia, Pa.
Philadelphia, Pa.
Centralia, IJI.
New York, N. Y.
Bartlesville, Okla.
Philadelphia, Pa.
Houston, Texas
New York, N. Y.
Chicago, 111-
East Chicago. Ind.
East Chicago, Ind.
New York, N. Y.
-------
INFORMATION SERIES 27
Environmental
Pollution Control
at Hot-Mix Asphalt Plants
\)'\..T DAVEMf:
1 @.~~'~.
,~ .... ~
" .... n
~)~!~~}
41.11\, 1',0'::)'"
. . to contribute to the National Pollution
Control Campaign
. . to increase awareness of the environmental
problems facing our nation today
. . to acquaint NAP A members with the nature
of these problems
. . to provide NAP A members with knowledge of the
methods and equipment now available to
control water and air pollution
THE NATIONAL ASPHALT PAVEMENT ASSOCIATION
-------
Introduction
Pollution is the presence in our environment
of man made substances in concentrations
sufficient to interfere with comfort, safety or
health; or, for that matter, with the full use
and enjoyment of property.
The hot mix asphalt plant is functional
rather than decorative. Heating of compo-
nent materials, grading, mixing and trans-
porting operations naturally produce dust,
smoke and fumes.
Today, our industry is faced with in-
creasingly stringent regulations, grown out
of public concern to protect our environ-
ment. Discounting the emotional aspect of
this concern, this technical material is pre-
sented to bring together existing knowledge
of the nature and control of dust, water pol-
lution, noise, odors and noxious gas pollut-
ants.
In 1905, the National Asphalt Pavement
Association, with the publication of tech-
nical series 17 and 17-A became one of the
first national associations to evidence con-
r.f!rn for the environmfmt. This bulletin is
presented in that spirit of continuing inter-
est by the hut mix asphalt industry in clean
air and clean water.
JOHN GRAY
Executive Director
-------
Contents
CHAPTER I: POLLUTANTS AT THE HOT-MIX
ASPHALT PLANT. . . . . . . . . . . . . . . . . .. . ...........
5
5
6
6
6
6
1.1
1.2
1.3
1.4
1.5
1.n
Particulate Pollutants. . . . . . . . . . . . . . . .. .......
Water Pollution. . . . . . . . . . . . . . . . . . . . . . . . . . .
Noise Pollution. . . . . . . . . . . . . . . . . .. ......
Odor Pollution. . . .. .....................,
Noxious Gas Pol1ution .... . .................
Particulate Pollution I'rom Aggregate
Stockpiles, Colel Feed Bins, Plant Grounds,
Roadways and Mix Disr.harge ....,.....,
6
CHAPTER II: POLL! ITION CONTROL
AT TILE HOT-MIX ASPHALT PLANT. .
"""""" .
7
7
7
7
8
8
9
2:1 Parliclliate Pollll!illlt Conlrol """""""'"
2.1'1 Description.........
2.12 C;clleral Procedure
2.'1:1 Iksign Datn . . . . . . . . . .
2.14 Types of DI181 Con t roJ Syslems ....
2.2 Wat!~I' Pollution Control. . . . . . . . .. .
2.:1 Noise Pollution Control. . . . . . . . . . . . .
2.4 Odor Conlrol . . . . . . . . .. ., .......... 10
2.5 Noxious Cas Control.............. .. . . . . .. 10
2.6 Control of Particulnte Pollution
in (hn Plant An)a . . . . . . . . . . . .. . .,...... JI)
................. .
....,........... .
....... .
9
CHAPTER III: »OLLlITiON CONTROL EQ1TIPMENT ..... 'J 1
3.1 Dry Dust C"lIpc!ors . . . . . . . . . . . . . .
:1.11 Skil11l1l1~I's flllll Expall~;jnn Chamlwrs ....
:1. 12 C"II(rirllgal f)/'y Dusl Coll,~!:Iors
:1.1:1 II;I!~ JlolJ~a)s
:1.2 Wid Washl!rs
3.21 Spray ChamlJlm; .
:1.22 (;1'lIlrilllgal Wet Washn
:1.2:1 DYllamic W,'I Was!H'r
:1.24 ()1'il'il:l~ Wid Wash"I'
:1.2!i VI~lIllIri W('I Wash('r
11
11
12
12
.. 13
13
1 :1
14
. .. 14
14
. ...........
, .........,
....... .
CHAPTER IV: TESTING PROCEDURES.. .. .......... 15
4.'1 Visual Tests. . ....... . . . . . . . '" ... . .. 15
4.2 Physical Tests. . . . . . . .. ......... """"'" 16
4.21 Slack Tests.. . . . . . . . .. 16
4.22 Ambienl Air Tests. . . . . . . . . . . . .. .......... 16
4.3 Noise Tests. . . . . . . . . .. . . . . . . .., ""'" 17
J\pr(~ndjx I-Clossary
J\ppnndix II-Cunversion Factors
. . . . . . . . . .
III
........ 20
-------
CHAPTER I
Hot-Mix
Asphalt Plant
Pollutants
1.1 Particulates
Stone dust. fly ash. soot and unburned
droplets of fuel oil comprise the main
source of particulates resulting from as-
phalt plant operation. During the drying
and screening process, stone dust may be
emitted into the air by reason of aggregate
fracture during this process. A stone dust
particle generally ranges from about 0.1
micron to more than 300 microns. (74 mi-
crons = 200 mesh; 44 microns = 325 mesh
and onp micron = 1/25.000 of an inch).
Solid pilrticles formeo during oil or gas
combustion are known as fly ash and soot.
Fly ash results from inpurities in fuel oil
which create a solid. rather than gaseous
combustion product. Fly ash particle size
rHnges from 1 to 100 microns. Type of fuel
useo relates directly to the fly ilsh proouc-
tion in the combustion process. Bunker C
residual fuels might be taken as an example
of fuels producing a high proportion of fly
ilsh. Soot consists of unburned carbon par-
ticles emitted from the combustion process
-rr~sulting from an insufficiency of oxygen
to oxidiw all carbon in the fuel.
The individuill particle size of soot is be-
low on!) micron. However. these particles
ildhere to one another and "pile up" into
much larger fluffy particles. Black smoke is
pssimtially very rine soot in suspension. al-
though some fly ash and dust is often
present in these emissions.
Wh(m combustion management is poor.
unhurneo oil droplets either are emitted
from the stack, or are deposited on the ag-
gregate in the dryer. These droplets range in
size from 1 to 100 microns. Because they
are sticky. other contnminants tend to ad-
hl~re 10 them, thus causing lnrger particles
to be formed. A poorly functioning burner.
lAck of air or insuffir:ient fuel oil heating
r.ontrihlltr~s to the formation of pol1utant
r)missions of this type.
By increasing burner heat and drum gas
velocity hourly production capacity of the
dryer may be boosted. But with the rise in
drum gas vP.locity. the amount of dust
carried from the dryer into the dust collec-
tion system is also increaser!. As an ex-
ample: for a typical aggregate.rlust carryout
is incr()nsed approximately 12!i p1)r cent by
incrensing drllm gns velocity by !i0 per cent
(from noD f(wt Iwr minutr) 10' noo feet per
minlltr)). Ahove noD feet pcr minll\() the rate
of incrcns() is flcccleratf'd. KI)()ping rlrum
glls vldor:ily low 1(,IH18 to minimize the dust
rcmovnl J!rohlf'm.
nllS! r:olll!c:lioll ill nspllllit plan Is is mostly
conc'~"I1f:tI with pnl'!icl(~R from 1 micron to
~lOo microns. (For C:l1mpnrison wilh sUmo-
nrd screen siws. milltls 200 mesh mflterial
is equivalrmt to minus 74 microns). On the
5
-------
avera~e about 5 per cent of cold aggregate
feed is minus 200 mesh. The dust reaching
the primary dust collector genHally is 50 to
70 per cent minus 200 mesh.
1.2 Water Pollutiun
Water pollution occurs when asphalt plant
contaminants enter nearby streams, rivers
or water sheds. Contaminants may consist
of minus 200 mesh particles, hot water,
water with sulfuric acid content, oil, gaso-
line, asphalt, soap or other compounds
commonly used around an asphalt plant.
1.:1 NoiM! I'ulllllioh
High level noises are ..reated in an asphalt
plant by the collision or friction of metal
ogainst metal, aggregate against aggregate,
and metal against aggregate, as well as by
the movement of compressed oil' into the
atmosphere and the combustion of pres-
surized fuel in Ihe hu mer,
The maximum noisl) level at asphalt
plants normally occurs ot the burner and
blower. Other high level noise occurs at the
hot screens, Ihe loaded pug mill and the
exhaust fan.
The moximum noise level at the Hot Mix
Plant ranges from 90-120 decibels "C" scalp.
at three feet distance. For purposes of noise
measurement and noise control at the as-
phalt plant, most state regulations conform
with the provisions of thl) Walsh-Healey Act.
This legislation cites as dangerous any noise
level exposure of 90 decihels on the "A"
scale fDr eight hours. Shorter exposure
times increase allowable decibel levels. In
addition to presenting a danger to em-
ployees. prolonged exposure to ex..essive
noise is irritating to neighbors around the
asphalt pJant.
J ,J (hi"r )'"lIlIlillla
The human sens(~ of smell con detect and
respond to many diff(~f(mt materials or
chrrnical COI11IHHlIlIls; some in conCf~ntra-
tions as low as (JlJf! part pr.r hill ion. Of.
f(~nsiv(' odOl's nl'Olind thn ilsphall plant
normally origini1t(~ from the nil' syslr.rn
slack or from Ilw IWI-mix trucks 'hr.nnalh
th(' pug mill. Odor,s fl'Om tlIP. stock ore
normally C;lus()d hy 11](' USf) of high sulfur
content fuel or unhllrner! natural gas. Odors
from thl) hol-mix truck are usually coused
by the mix coming ill conlnct with kerosp.ne
fi
or fuel oil coated truck bodies. Airborne
particulate matter is not normally con-
sidered as a source of odor stimulation,
1.5 Nuxious Gas Pollution
Fuel combustion in asphalt plants produces
combustion products varying with the type
fuel used, and with the temperature and
efficiency of the combustion process. When
pollutants of Ihis type occur, the most fre-
quent are carbon monoxide. oxides of
sulfur (sulfur dioxide and trioxide) and
oxides of nitrogen (nitrogen dioxide and
nitric oxide).
Sulfur dioxide is probably the most
troublesome of these. Fuel containing ex-
cess sulfur may create sulfur dioxide. It is a
colorless gas which in its pure state is about
twice as heavy as air. In sufficient intensity
it causes a choking sensation and respiratory
irritation in both humans Rnd animals and
could also I)() damaging to vegetation.
Harmful con..r.nlralions of sulphur art! not
normally associated with asphalt plants.
Carbon monoxide is a colorless gas,
without odor, which is produced in any
combustion device using gas or oil, when
theff! is innd(~quilte oxygen to complete the
oxidalion to form carbon dioxide. If the
comhustion process is poorly managed,
SOmf) carbon monoxide is produced. In a
properly fired plant. carbon is almost com-
pletely converteo to carbon dioxide, which
is not toxic. Production of carbon monox-
ide at well managed asphalt plants is
negligible.
Nitrogen oxides arr. formed when air
[composed mainly of nitrogr.n and oxygen)
is h!~nt(~d to 1,SOO'F. or more by high tem-
peraluf(! flames. Nitrogen rlioxidp. is a
colorlr~ss gas, highly irritnting to eyes and
lun,~s. The Iwrcr.ntages of thesr. oxides in
nn asphalt plrlTlt stack exhrHlsl IIrc np.gli-
gihlp..
I.i [',.1'1;,.111.11,' Pollution i~:tlll ;\gg'PI',oI,:
""'od,pilf'~. (:nld 1'1" ,\ Bins. !'Iallt
(;rllu,' ,I~, k ,..d',';I\!i .11,d i\1i" !)i~-
ch;. r;~p
This Iyp(~ of pollution ..nn lw callsr.d by
th!' following faclors:
1\. Cf~n{~rill poor III)us()kf)f!ping
n. Exposr.rI [}ggl'f~gatp. storagl) areas
C. !)nconlrollpd traffic conditions
D. Natural plcmenls
-------
CHAPTER II
Pollution
Control
at the Hot-Mix
Asphalt Plant
2.1 Particulate Pollutant Control
The prime objective of air pollution con-
trol around asphalt plants is 10 eliminate.
to thf' (Jpgrf'e feasible. dust {'missions and
otl1l'l' ;lir poll\llants. State nnd loen] codes
and I'(:gulntions must bf' stl'ictl~' obsl'I'ved.
Wlwn plant owners and 0IJl'rillol's comply
fully with (;odl!s. ol'dinilncl!s. and l'I:guln-
liuns, 111I:ir opuralions al'(! lugally pl'otech!d.
Employees al'(! pmviJ(:d wilh II c\()an, safe
pial:!! to work. Tlw own()r hils reducI!d
weal' on plan 1 equipment caused by excI~s-
siv(! dusl (~l11issions. In some operations,
II1\) dusl conll'Ol proc()ss rm;laims \lsnl'ul
fine matmials.
Wh,m thf' public relations Ilspects of air
pollution cunlrol al'l! ignored. emotional is-
SIWS may caust: politic;lI repercussions lead-
ing to more stringp.nt regulillions. Owners
and operalol's should make cl:rtain that
10(;ill ol'l'icinls fully undNslnnd the nnture
of II1\) air pollution problem, and more im-
porlantly. Ihal neighbors and neighboring
cOlllmuniti()s be informed of progress in the
right agninsl air pollution. In this WilY,
citiwn (;omplnints cnn he held to a mini-
mum.
2.11 Description
Thl: main sources, or pUl'ticulah) I!mis-
siol1s 1'1'0111 111() plant aI'(' the aggregate
dl'Ycl', scrl!(:n. wldgh and mixing nrcas. and
Ihe hot nHlh)rial eh!vator.
Tlw air drawn through or from these
units has a high particulate conlent, most
of which IllUSt hI' removed by thf' dust
control c!quipment which is pilrt of the air
SYStl)lll. TIll! air drawn through the dryer
normally is cnlled "Dryer Air"; that drawn
frolll till' SCI'(!(!Il cover, weigh and mix ilrea
dust ()JIc!OSurl), and som!! limcs the hot
Illilterial elevator has heen called various
names-"Fugitive Air", "Scavenger Air",
alltl "Nuisance Air". We shall refer to it as
"Fugitive Air" system. We shall also refer
to the entire system as the "Dryer-Fugitive
Air System".
2.12 General Procedure
Wlwn alterations or additiolls are
mad!! In Ih(! dry(!r-fugitivc air sysll!1l1 un-
df'r today's laws it is nlmnsl invariably
Iln(;l!ssary 10 apply 1'01' a pl)rlllit from tlw
Incal IIiI' pollution conlrol olTicials And
pl'IHwnt to them plnns covnring Ihe pro-
pos(!d (;hnng«~s, ilnd daln giving tIll! nntici-
pall'l1 dllsl !!ll1issions III IItll1osplwl't). In
I1lllny slal(!s it is 1't!l]uired thAt Ihis work \w
pl'l'forllwd by a Pl'lIf('S!;jnnlll I!ngilwnl' l'l!gis-
II'rl'd in Ihal parlit:lIlar slale.
Till) prOC(!dlll'e In he f()llow(~d in de-
signing the dryer-rugitivl' air system in
gf!lleral is ilS follows:
7
-------
A. A set of pollution control specifi-
cations under which the plant air system
will operate should be obtained, and the
allowable dust emissions to atmosphere de-
terminl!d. plus any ollwr ~pecinc require-
ments,
n. The required dryer and fugitive air
volumes should be obtained from the
original plant manufacturer to assure suffi-
cient air for proper plant operation at the
mquired produc;lion rate. When this in-
formation is obtainm1. the anticipated static
, pressure drop of the dryer, ductwork, and
any existing dust collecting units which are
to be used in the revised system should be
determined.
C. A thorough study of available sys-
tems should he made, anll the one best
suiled 10 the requirements selected, This
study should wnsider the various factors
involved-efficiency of I~qllipment, result-
ant dust emission to atmosphere. the slll-
vaging of dry coller.tml cIust. the total cost,
etc.
This total cost shoulcl inc;]ude not only
the obvious pricI~ of Ihe physic;al parts of
the system, but also those ill~ms whir.h may
be overlooked. Some of these items are:
1) Anticipated maintenance costs.
2) Cost of water.
3) Cost of electricity or diesel power.
4) Method and cost of sludge disposal
of the washer ernuent.
5) Cost of rP.turning dry collected dust
either to the hot elevator or to
storage.
6) The volLll! of rlry cIust normalIy lost
as washer sludge c;omparecl to the
additional cost of II secondary cIry
dust colIm:tor which wou\cI reclaim
part of this lost dust.
D. After the permit to construct has
been granted and the new equipment in-
stlilled, most of the IWW laws require thllt
the cIust emission to atmosphere be tested
under supervision of a profl!ssional engi-
Iw(:r registered in that slille, with nil' polIu-
tion authorities witnt!ssing the actual tests.
The resl,lIls are tlwn filed with the air pol-
lulion control commission IInd the tests
C(~rtifit)d so thaI tll(! plnnl can operntn
legaIly. II is recornnwl'llled Ihnl extreme
can~ IJ(~ tilken in selecling Ilw company to
run 111t~ r(!{I'IiI't~d dllsl It~sts to mnk!! surl! of
ils nhilily and reputillioll nntl of its !lC-
(;t~pl;lnce hy tht~ IIiI' pollution nlllhol'itiwi.
2.1:1 nl~!iign Data
1\. UrYf:,',FlIgitivIJ Ail'
Plant production is largely dependent
on the pl'Opl!J' volume of dryer air being fur-
nished. Data call be obtained from the orig-
inal plant manufacturer. It must be sufficient
8
to carry away the moisture liberated from
the aggregate passing through the drYt~r,
and furnish sufficinnt sec;ondary air for
bllnwr comhustion.
If tlris filcl is not considl'red and in-
sutTici(~nl ail' is provided in the system, [hI!
result will be lowered plant production. In
many cases dust emission from the dryer
and dryer discharge will occur in the area
of the burner.
Insufficien t air will also cause im-
proper fuel combustion resulting in high
fuel costs and when fuel oil is used, II
dark stliCk.
Sufficient fugitive air should be pro-
vided to !!Iiminate dust emissions from the
asphalt plant screen cover, dust enclosure
around the weigh IInd mixer area amI, in
some cases, tlw hot rnaterilll elevator. Thl)
correct voluml) can also be ohtained from
the original plant manufacturer. Most of
them \'t!comml!11(1 that the fugitive air be
equal to approximately 10 per cent of the
required dryer air.
B. St(J!i(; Prossllres
Static pressure generally is rcCerred to
as inches of water at 70°F. This pressure
represents the rt)sistance to air now offered
by the unit being considered. The 70°F.
temperature is used because most fan
mllnufncturers hilvt~ run tlwir laboratory
tesls and printed their fan performnnce
tables using this temperature. The plant or
equipment manufacturer should he able to
provide the static pressure of this particu-
lar equipment.
If IIctual slatic; preSS\ll't!s are taken,
they must be made with tlw plant in full
opl~ration. Th(~ pressures and air tempera-
tures obtained must be converted to the
standard 70°F.
C. Fan
The fan should be of the heavy duty
type typically used in asphalt plant sys-
t()ms. Il would be sized to handle the re-
quired total air volume and total static
prossurt). Gr!!n! cnr() should he laken in its
selection to avoid excessiv(~ speed. Fans
used in asphalt plant systwns should have
thu powur nuc;dsary to ov('rcnrt1U thu total
slald; prussul'u of the syst(~m. If thl) slatic
prf!SSIII'f: is too high, it may I)(~ nt~c(!ssal'y 10
IIsn an additional ran or' a Sl)(~cial high
pl'(!HSIII'I~ 1111 i I. 'I'h is is gmwl'all y l'tHllii I'm I
wlwil high P"('SS\ll'(! orilk!! Iypn WI!!.
wash(~rH 01'(' IIst!d.
2.1.t Types of Dust Control Systems
At the prust:nt time expansion chllm-
hf!rS, skil11m(~rs, cp.ntrifugal type dry collec-
tOl'H, wet washers and bag house dust
collectors arc the items normally used in
asphalt plant dust control systems. These
-------
will I)p, (;overed in Chapter II!. Theso units
.III' 1:I'rWrillly uSfHl in threl'! Iypes of control
~\."t"Il1S :
A, , )rv We' S}'slr.m
Thi!; would r.onsist of a centrifugal
I,VI"' dry dllst (;olll~ctor followed by a fan,
;111.1 11)(~11 n w('1 waslwr. This system con
111"1'1 lI1iJl1Y existing nil' pollution r.odes if
1111, /!lOS! prricil'n! washr.rs are used. It is
Ih,: cllP.illH'st of all thl' systl'ms available
11111 h,ls Ihe disildvantnge of losing mflny of
Ih" fines drawn from the dryer to Ihe
washr,r sr.ltling hnsin. The loss of these
filll'S shoilld III: takon inlo consid(!rIlIion
whIm d(~tprmining the flr.tual cost of tlw
';ystl:m, 10,L:l'lhl:r with the cost of water,
sl'llling hasin construr.lion, cleaning of Ihe
spltling basin. disposal of the wet mud or
"I'lrlgp, possihl,. wilter pollution prohlems.
;llIrI ;Inlicipafl:d maintr.nance ann electrical
1:lIr'l'I'111 costs.
) Dry-/Jry-Wet System
This syslt:m would normally have {\
'illlgl.. I,ngp d,;mwtr.r primary cfmtrifugal
Iypl' dry dust colleclor, It would be fol-
Inwl'd by " sl'condary multiple tube cen-
Irilllgnl IYIlI: dry dust collector or 11 high
1'I!II:il,ncy cyclone grouping which under
iI\'I'riigl' condillfJlls would reclaim a high
[lprcenliJgl~ of Ihr. dust not collected by the
pl'imary unit. This is dust which in the
'Iry-wct ~YSII'1I1 would lwcomo sludge in
Ihl' wiishor sotlJing basin.
The sr.r:ondary colleclor normally is
rollowl'rI hy ftlf: filn with the wet washer
Ine;ltl'rI Oil Ihl~ discharge side of the fan.
0111' of thl' difficulties with this system
is 10 keep its total static pressure within
till' limits in which the fan must operate.
C. nrV Systnlll
This s\,stt:m uses a hflg houst! dust
colll'elm In process Ihl' dlist-larll:1l ail' of
Ih,' drYI!I'-fligili\'I~ nil' syslr.m. The bag
11IIu:;(, enllf'r;tol' can Iw prect!ded by a cen-
Irililgal dry dlls! collr.ctor. or skimmer.
This typl' of collpclor I1lmosl totally
I'I'claill1s 1111' dllst drilwll from thn plant and
dr\,I:I', " has il low total stotic pressure
illlrl, cnl1sPfllII'llIly, n:qllil't:9 11 smaller fan.
Thnse units in their presont design
l1a\'I' ht!lm IISl'd on IIsphalt pion Is in the
I Jnlll'd Sliilr.s for approximately fOllr yp.Rrs.
Ktlnwl(~dgl' of thdr maintenance costs and
r:xlJt:elt:d lift: illl' nol complt:I(!. Care should
h" liiKl'n 10 liSt: (;ollt:ctor hags capablo of
"ii!lilling 1111: high t()mperiitur(~ gases from
Ih,' ilsphall pLIJIt nir syslr:m.
/\ddililJl1;t! nquiprnent would include
1I1f'1 flllwf;tlil. !I'fTlIWri1tllrt: controls to modu-
all' 1111: 11111'11I'r 10 prt:v[~nl t:xc[!ssivn IIiI'
Ir'I1'1'f'I';IIIII'I' ill 111{: hng hOllsr:, air COlT1pJ'(~s-
:;on., PJlt'IIII1i1lic iiir sysll~llIs [,nd dusl COil-
vf'Villg syslt:ms.
2.1 Water P~itition Control
At this time, most owners and operators
fire primarily concernen with air pollution,
hut water pollution cannot he ignored. In
orner to prevent water pollution, slurry
must be captured and treated.
A well designed settling basin is one
answer to this problem. It must be large
enough and so compartmented as to allow
for settling and cooling. Data for the con-
struction of properly designed settling
basins can be obtained from asphalt plant
manufacturers.
/\1 confinp.d plant sites where settling
systems must be kept to a minimum area,
or at temporary sites where settling ponds
cannot be installed, prefabricated settling
tanks may be used. These tanks are com-
partmenten and equipped with drag chains
or dewatering screws to remove solids
and recirculate cleaned water through the
washer.
If neCf!SSary, seHling can be hastened
ilnd made mol'(: efft!ctive by the use of
chl!mica I tlocculents.
Settling basin water acidity or alkalinity
must be frequently checked. This can be
done easily with litmus paper or other teat
methods.
2.3 Noise Pollution Control
Noise control is relatively new in our in-
dustry. It is now achieved through isola-
tion, soundproofing and personal protection
devices.
The loudest noises around an asphalt
plant general1y originate from the burner.
Most burners sold today are automatic or
remotely controlled, with the operator lo-
cated some distance away in a control
house, where exposure level is reduced.
Since the noise genernted is of low fre-
quency, it is difficult to suppress with
unything less than a heflvy mass; i.e., leaded
sheets or a soundproofed structure. Gas
fired burners usually account for a lower
dp.cibe! lovel thAn preheated fllld air-mixed
fuel oils.
Thore art! Home noise abnt(~mnnt codes
which set maximum allowable 'decibel levels
at property lines. This code will probably
allow the highosl dogree of enforcemr.nt.
Most codes follow the Walsh-Healey Act
which Allows a maximum exposurp of 90
decibels "A" scale for eight hours. The
scale graduates with a higher decibel allow-
nncp. as the time of exposure becomes less.
Tho mnnSlIl'ement expressed in decibels is
not Ii tlP.!I r. This menns that to reduce the
noise hy hllH will only decrf:ns(: the noise
Inv(:! hy 11 few dl~cihols. The dr:ci,1wl !nvel at
II rlislllncn is iiIT(:ctr.d similflrly in that it
dr:crl!lIsr.s slowly. For instance, fI noise level
9
-------
of 90 decibels at a 10 foot distance may only
decrease to 87 decibels at a 25 foot distance.
2.4 Odor ContrQI
Prp.sent air pollution control regulations
gtmerally prohibit the use of high sulphur
content fuels and therr.fore, removes the
source of past stack odor problems.
To prevent offensive odors from hot-mix
trucks while loading, kerosine should be
eliminated as coating for truck bodies. As
substitutes, water-lime slurries or other com-
pounds rI!IHlily flvailable should he used.
The hot-mix tempcmlure should lw kept as
low as possible.
2.5 Noxious Gas Control
Tht~ control of noxious gases depends on
proper nnd efficient combustion of fuel nnd
the use of low sulfur content fuels. The
sulfur conll~nt of fuels is now governed by
pollution control Inws in most stntes. At
this time, there is no pollution control
ag(mcy which specifics a reduction in
noxious gnses to n point where the hot-
mix nsphnlt induslry would be advcrsdy
affected.
2.6 The Control of Particulate
Pollution in the Plant Area
A. All aggregntes stored at the plnnt
sill! should hI! mnintained in such n condi-
tion ns to prev(!nt dust from hecoming wind-
horne while in sloragt! or being hnndled,
loaded or transported. Suitable precnutions
mny include:
1. Wetting of malt'nal with water or
otlwr liquid thai would prevI:nt dust
from becoming wind-borne.
10
2. The location of stockpiles in an area
that is protected from the prevailing
winds.
3. The installation of a wind-break
(fence, trees, walls, etc.) that would I
protect stockpiles from direct ex-
posure to the prevailing winds.
4. The storage of aggregate in bins,
silos or other type of enclosure.
5. The careful operation of loading and
hauling equipment to prevent the
generation of fugitive dust.
B. All areas of the plant site that arc
used for vehide operation and travel should
he maintained in such a condition as to pre-
vent dust from bP.coming wind-borne.
1. All principal driveways and haul-
roads should be'
a) Paved with a material that can
be cleaned of accumulated dust at
reasonable periods.
b) Treated with a dust' laying ma-
terial when they remain in an un-
paved condition.
2. Vehicle operation within the plant
site should be maintained at a rea-
sonable speed (10 MPH).
3. All paved roadways, driveways and
parking areas should be cleaned
frequently in such a manner as to
prevent the genei'Otion of fugitive
dust.
C. The plant equipment and site should
hI! cleaned frl~quently of accumulated dust,
dirt and spilled and/or wasted materials to
eliminate a pot(:ntial fugitive dust source.
-------
CHAPTER III
Pollution
Control
Equipment
The main purpose of an ail' pollution con-
trol system is to remove particulate matter
from the gas stream that leaves the asphalt
plant through th(~ stack. This particulate
matter hus diffnl'fmt chilracleristics from
planl to plant. Som(~ uf the mosl important
of these charactnristics are:
1) Grain size distribution
2) Particle shape
3) Demity
4) Abrasiveness
5) Toxicity, etc.
Tlw r(~moval of these particulates from
tlw gas strnam must be considered on the
basis of thn process involved: operating,
construction and economic factors. There
al'l~ two gnn(~ral types of air pollution con-
11'01 equipmnnt, lIum(~ly:
1) Dry coll(1(:lors
2) W(~t washers
Each of tIH~S(' hils many diff(:renl types
and (~ach hils its own function and applica-
tion in Ilw ail' pollution conlrol system of
an asphalt plant.
:1.1 J)r~/ Husl Culll!f:lurs
This type of equipment collects particles
from the air stream and allows these "fines"
to he reintroduced into the manufacturing
proC(~ss. There arc three major types of
dry collectors used:
1) Skimmers and expansion chambers.
2) Centrifugal dry dust collectors.
:.I) Bag house collectors.
EXPANSI()N CIIAMBER
:\.11 Skimnwl's alllt Expansion
Cham111:1'!!
These simple particle collectors arc
based on the principle of d(~creasing the
velocity of the exhaust gas by expanding
the ductwork to a point where it allows
air borne particles to reach a "terminal
settling velocity" Rnd settle out hy gravity.
If hames or shelves are installed in the
chiunhers,
-------
-
411
.--
.--
~c-:
I
/\
CENTRIFUGAL
DRY DUST COLU:CTOR
3.12 Centrifugal Dry Dust C.ollectors
1\. SlIlgk Cenl.nll/gfd Dry Collcctor
"L(Jrgf~ lJjfllJ1elr:r"
Centrifugal dry dust collectors separate
Hw dust particles from tlw gus slream by
Ihe use of centrifugal and gravitational
for(;(~s. The physical principlr upplied is
that parlicles having a higher density than
the carrying gas arf! rorc(~d against the wall
of the cone in a spinning motion. The
smaller the diameter of the cone becomes,
the faster th(~ particll~s will travel. Therefore,
tlw parlicll~s will hecome increasingly
heavy through !:(~ntrirugal force as they
['-.
.j ~
/ ----:-.. - .J ')
I' /
I '
~'" /-1/
::.::-... , '
Gas I nle!
MUL TITUBE
COLLECTOR
/'" Valve
12
travd downward in a spinning motion
towards tl1(' IJOtlom of the r:olh~ctor cone.
A given centrifugal dry dust c(Jlll~ctor, or
cycloI1l~, Iws n r.mlain dfl~ctive minimum
pnrticle si/.I~. 1\11 parlich~s smnll!'!' Ihnll this
siZ!! norm.illy I(~av(~ Ihe colleclor with gnscs
by f!11:aIlS of Ih(~ rising inlwr vortex through
Ihf~ top gas oUllet. All particles lar.L:('r than
the minimum size are r.ollected and dis-
charged through the bottom opening of the
collector cone.
The pressure differencr~s betwl~en the
outside and the inside of the bottom of the
collector cone are extremely important. It
is imperative that the r.one bottom be scaled
off tightly by a discharge valve or gate to
prevent intake of atmospheric air and loss
of collection efficiency.
B. Multiple Tube Centrifugal Dry !Just
Collector" Small Diameter"
This type is similar to thl: aIle d(~.
scribed in Ih(~ preceding ser.lion "A", ex-
cP.pt; the small diameter r.ollectors <11'1'
lllolll1t[~d within FI r.ommon hopper with on,-
common galp. or valvp. at Ihe hopper hot 10m
discharge.
:~. 1:1 Bag HOUSH Collectors
The application of the modern fabric
dust collector to the asphalt plant air sys-
tem is fairly new.
A. There arc two basic types of fahric
r.ollcctors:
1 The Compartmented Bag Collector
The compartmented bag collector is
used with either reverse air flow or shaker
type bag cleaning. This type of collector is
divided into several compartments each with
- Outlet Tube
- Spin Vanes
COLLECTOR
ELEMENT
-------
its own damper and bag cleaning system.
One compartment at a time can be taken out
of sprvice to release the dust from the bags
into the bollom hopper.
The dust laden air enters the collector
and passes through the inside of the bags
where the dust is filtered out as clean gas
paslJes through the bags and out of the
system. Tlw hags ilre self-supporting be-
cause IllI! IIi/' is cIeanl~d while flowing from
the inside out. (Jsually woven fabrics are
wwd nllhollgh fell fllbrics hnve been used
with some success.
The air-to-cloth rntio or cloth velocity
must he kl'pt quite low for this typl' of
collector. It is usually between two amI
three CFM of air per square foot of cloth
surface.
2 Uncompartmented Bag Collectors
This type employs the use of com-
prc:;s,~d ilir to sharply reverse the air !low
Cleaned-gas oullet
.
dR....r5e-lir jlts
I ;!p:\
L," "
trl-- Reverse-air
1,1 Frame bag
- - support
l-
Dusty-gas inlet
~
,
"-Dust hopper
Valve ---
HAG IIOlJSE
Illrollgh Ihl' hags to apply a shor.k 10 the
du';! c,d'd!. This pl'rllIits Ih(' ww of high nir-
lo-cloth ratios III' clolh vl:l()cilil~S of from
!iVI' 10 six and olw-half CFM pl'I' square
foot of cloth surfnC!~.
The dirty IIiI' pntt~rs the hopper, rises
Ilpward arollnd tlw olltside of Ihe bngs and
passt.s through tIlt' fahric from 1111' outside
111. Tlw dllst is collecled on tlw IJl,lsid(~ sur-
LICI' 01' tlw hllg alld IllI! clean gns PIIRSPS up-
ward throllgh !he insidt!, Ollt IIn Opl!n (md
10 all 1.,l1l1usl mllnifold.
This collector l'I~quires wire cag(~s or
sonw Iype of support inside of tlw bags to
JlI'I'v(~nt collnpsing.
'1'111' cleaning of the bags is done in
sll1l1ll groups, nnd docs not afft~ct the dryer
,III' volume.
A \,(:ry stllrdy fahric must bt~ uSIHI Iw-
CilllSI' of t'he higl; lev!!l of (ml'rgy IIsmi in
r:ll'illlillg Ihl~ hngs, and bec,lIlsP tilt! cloth is
repeatedly moving on and off the bag cages
during cleaning. The thoroughness of clean-
ing requires the use of felt instead of woven
fabrics to obtain uniform collection.
. B. Insulation
Hot, wet air is drawn from the dryer
into the air system and it must be kept
above the dew point to prevent condensa-
tion within the dust collector. Therefore,
proper insulation of the collector is neces-
sary.
C. Fabrics
The success of the fabric collector
hasically depends on the fabric and fiber
I'I'O/J! which thl~ bngs are made. The fnhrics
used in asphalt plant colleclors are:
1) Gloss
Woven, filnment warp and bulked fill
yarns finished or treated with n lubri-
cant such as silicone to prevent fibers
from breaking through self-nbrasion
during fl(!xing. r:ood for continuous
0lwration at !iOO.F.
2) Polyesters, Dacron, Etc.
WOV(!I1, all spun and felted. Maximum
temperature 270.F.
3) Nomex Type Nylon
Woven, all spun and feIred. Good for
temperatures up to 400.F.
3.2 Wet Washers
Wet washers can be classified on the basis
of pressure drop into low, medium and high
energy devices. There are five basic design
types:
TYPE CATEGORY
1. Spray Chamber Low Energy
2. Centrifugal or
Cyclonic
:1. Dynamic
4. Orifice
fl. Venluri
Low Energy
Medium Energy
Medium/Higl') Energy
Medium/High Energy
3.21 Spray Chamber
The simplest Iype of washl!l' Is a
chamber wilh spray nozzleR. Its overall
dficiency is low. By installing bames and
subjecting the baffles to water sprays, the
dficiency can be somewhat incr(Jased.
3.22 Centrifugal or Cyclonic Wet
Washer
In Ihis IIlIit, till! dURt ladm] gas enters
tallgt!nlially nnd spirnls through the scrub-
h(~r in a continuously rotilling path.
In onl! type sprays nre lor.aled axially
nenr the center of the scrubber with their
nozzles directed radially toward the walls.
The spray sweeps across the path of the gas
stn~nm intcrr.f~ptillg find entrapping the dust
parlicles. TIll! ctmlrifugal motion of the
Spl'ilY impartecl hy the rolnting gns cfluses
13
-------
OUJlet
L)
Gas Inlet
Liquid Inlets
CENTRIFUGAL
WET WASHER
~
Dr din
Dirt and Water
Discharaed at
Blade Tips
Dirty Air Inlet
-- From Prewetter
WET FAN SECTION ONLY
OF DYNAMIC WASHER
To Atmosphere
,/' ,
" /" /
1"""",- --'"
I -----
\~=~ ~
I -
I
\ ./"
Inlet
- ..- Onflce PI,lle
.~ Velocity
. Access Door
ORIFICE WET WASHER
14
the droplets to impinge against the washer
walls and then drain to the bottom by
gravitation,
In another type, the spray nozzles are
mounted on the wall and protrude into the
washer, The advantage of this type is that
any nozzle may easily he serviced or re-
placed.
:1 :~:l J)yu;IIdi(' Wash,-;
This is in essence a centrifugal wet
washer of which the fan is an integral part
and wh('re the fan impeller is sprayed with
willer, Its increased efficiency over a cen-
trifugnl washer is due to impingement on
the wP.t fan impell(~r blades find howling.
, (~I ,Ii, 4' \\1'1 \y.....'.,.,
This washer is a device when'! the gas
is forcp.d through an orifice together with the
scrubbing liquid and causes impingement.
The slurry enters the separator tank and
the clean gas leaves through the top of the
tank.
.1.:'< ',,'..,duri \VeI \\' ''''!iI''
The venturi scrubber consists in prin-
ciple of a "throat" and a divergent section.
Dust laden gas enters the convergent sec-
tion and is accelerated to high velocity as
it approaches the throat.
Water as scrubbing liquid is injected
either directly into the "throat" section or
the top of the venturi. The high velocity
gas stream atomizes the liquid into a fine
mist. ,
Gas and dust laden liquid enter the
separator, usually a cyclone, where the
liquid is thrown to the walls by centrjfugal
forces and drains tf) the bottom by gravity.
The clean gas exits through the upper por-
tion of the separator.
VENTURI WET WASHER
Gas Inlet
\
-
liquid Inlet
Throat /
Venturi
Separator
Separator
Inlet Nozzle
.~...~~
. .-;
- "~~r
:;" ~
-------
CHAPTER IV
Pollution
Testing
Procedures
In order to estflblish the quantity and type
of particulAle pollution, certain tests are
required. These range from visual observa-
lions to sophisticated procedures requiring
highly accurate instruments to measure
quantities that appear infinitely small to
the casually interested layman,
4.1 Visual Tests
The only visual test used at hot-mix plants
is the Ringelmann Chart test. The Ringel-
mann Chart is a device which employs five
equal steps between white and black to
measure the "opacity" from a single stack
by color comparison.
A. The five steps are described as follows:
Card 0 All white, 100% light
transmission
20% black, 80% light
I ransmission
400/0 black, 60% light
transmission
GO%. black, 40% light
transmission
80% blHck, 20% light
Irnnsmission
An black, no light
transmission
Card 1
Card 2
Card 3
Card 4
Card 5
B. Use of the Chart:
1. It is held on a level with the eye, by
observer, as nearly as possible in line
with the stack. The observer should
stand at a distance of between 100 feet
and % mile from the stack.
2. The ohserver glances from the
plume as it issues from the stack and
notes the number of the chart most
nearly COrrt!sponding with the shade
of the plume. He records this number
together with the time of observation.
3. Observations are repeated at 1/4 or
1/2 minute intervals. The readings are
then reduct~d to the total equivalent of
No.1 smoke as a standard. No.1
smoke Iwing 20'1.. dnnse, Ihe percentage
r!mu;ity of thl! smoke for the entire
period of o\!sNvations is obtained by
the formulll:
Equival(:ntunits of No.1 smoke X 20%
NumlJP.r of observalions
PnrC:I!lIt agt: smokc! Ih:nsi t y t
'I'll!! IIlIgll: of IIII! Sllll, ov(!rcasl sky and
air !lOlllltioll from sourc:(!s nl/I!!I' than the
asphalt plant, etc., hllve 10 be compensated
for in thl: Ringelmann determination. Al-
though this test is dependent on personal
,1. Atmuspheric Survl'Y TrOlnjn~ Courso Monunl; Section
V-Atmospheric Sompl,ng Equlpmont-Apro8ols Visual
novices; Puhlic I h'olil- Scn'i<:e; US. Deportment of
J lealth, Educotion ond Welfare; P. 1.
15
-------
RINGELMANN SMOKE CHART
Fqlll\'fllrni of 20% BlAck
Equlvnlont of 40% Blnck
Eqlllvnlnnf 0180% D\nr.k
judgmr~nl. ilis widr~ly used, The originnl pur-
pose of this chnrt wns not to determine vio-
lators ~ince it does not provide any means
1'01' nwas\ll'ing Ilw qua\ltity of pollutants.
Other visual tesls ;lv;1ilablc but not ap-
plied at this time are the umbrascope and
the smokescope.
A. The umbras cope employs four movable
grilY glass disr.s which dl~tr~rmine Ihc sllildl~
of the plume. The equivalent of Ringelmann
No. :1 is onc disr, OIl the ulllbrascope sr.al(),
B. The smokescope is baBed on a refef(mce
rilm that allows Ih(! r,ol11parison of smoke
shades without thl~ nl~l~d to refocus Ihe ey[~
from the reference to the plume,
"Tlw difl'ir,ultil's inherent in the visunl
I'valuillion or S!l10kl' pl\lmes do not climi-
natl~ !lw possihi]ity of \Ising such obscrva-
liolls as on aid in coni rolling rill' pollulioIl,
In principlt" thf~ Ringrdmann Chart sho\lld
hI' usdul in I~slimating the obscuring or
vision by plnl1l!!s and in setting limits to
I.IJII!rnl thl! visibilily dr~gl'adati()n downward
from n sourr.e or particulate matter, In
praclice, however, !II!) problem is ext[,(~lllely
r,omfJlf~x and requirps extensiv(~ sludy 10
dl~Vldop 1Jl?ltr~r lechniqlws for mra~u!'ing Ih!~
contrib\ltion of individual plunwH to visi-
lJilily prohl[~Il1S." 2
4.2 Physical Tests
Tlw rnl~ilsur(~mpol or qUilnlitil~S of pollulanls
arr~ bns(~d on Ihp volunH' of tlw gas slr(~ilm
Ihal cilrril~S Ihl~ poll\ltants, The units of
IllI'ilSU rpmen t for gas volume are ei I her
~\;lll(l;\I'(1 cuhic nwkr or standard cubic
fool. TIII~ unils of mt'asurl~menl for par-
((i
~ /\ir (JUOllly ('r/furlfl FOf Porti('lJlnfl' Mull!'/'; U.S 1Jf'-
11.1111111'111 cd 111',11111. LdlJllIllClI\ UIIIi Wplldl'O: I'uhlll
'11',11111 ';( I \ ,I,( II 'I It)
. .'.,;,.':.""... .'.'.'.:
. . . .'iI,'... ..,'Ii. . 'Ii',
Ii:.. .,iI". .;. .'.'.;..;
.'18,:... .'.'. 8'....
'.'.1..'.'.. .......
... ........ ...'.,
.:. .'. ...;.,. .'.'. Ii,;
ii ii'...'. ..'.....
'. .,. ...,..". ',.,,:.,... .'
.,1.,.. .",.,...,...-
\ . ',.4.,." 1",
.,.,. ..'.. ..,.:...
.i..:;_,. ",.I! '11!!,:8'8;.
.,.'.. ....'..'...
'.". .;...'-,. .,.:.,,,:.'.,
.... .;:. 81. .. ...'..
.''':. .IU .'. .'..,.,iI
...,:.,.,.'. .'. ... ..,11
. .,..,.:. .,......
.,...".;i!,.'. ..:.,.'.'.
.'.'''.'.~.'.,till).,D .'
II. ,.. .~;~:.. ,1I:r""
-------
,lIid ~;II'I'I Illtdillll!!) Ilillllpll'l' tlllvidoflntl by
Ilt'IIII'1I1I IIlId SIIIIKnr, d nl. Othnr vl'rHioliH
t'\i.', 11111 011'1' ;diKfl ill tllllir flllll:lioIlH. A
rlill (>I fll'OPlll'tiol1ml fjlt~r papflr is posi-
IIIIIH~" IlI'lwI'I'1I tlHl illtakll 1111111 and a vac-
1111111 1,(111111'<.11(111. Air is drawn Ihrough th(1
Itllf'l' for a ~I'll'cltld tinH', usually one to
1'0111' hOllrs, '1'1111 main hasis for Ilvaluating
sill11pll'S is optical hut also renm:tflnce and
li~:hl Irnnsmission IT1fIY he ml~asured. These
111rI'1' n1!lasurl'll1l~nts correlate fairly well
O\fII' short sampling periods.
n. IIlgl, Volume Samplers
A morlern high volume sampler is gen-
(Irallv I'xposed insidf~ a case with a hori-
'IOntal filtl'r surface facing upward. A roof
1\1 kl'(,p out rain and snow is provided over
thl' casl'. Fi!tl'rs arP. made of glass or syn-
IIlf'tir: fi!H'r. SineI' the fihP.rs are suhstantially
1('ss than onP. micron in eliamP.tP.r, they fire
hi~:hh' I'fficil'nl. SamplP.s arc normally r.ol-
l('c ',I for 24 hours and s
-------
Air Clr.annr: A device designed for th(! pur-
pose of removing atmospheric air-home
impurities such as dusts, gases, vapors,
fumes and smokes.
Air PolIution: The presence in the outdoor
atmosphere of one or more contaminants
in such quantities and of such duriltion
as to cause an unreasonable interference
with human, animal or plant life or the
reasonable use of property.
Air, Standard: Air with a density of 0.075 lb.
per cubic foot. This is substantiaJIy equiv-
alent to dry air at 70°F. and 29.92 in. rHg)
barometer.
APPENDIX I
DN:ihrd: To measl1l'p. thp. h~vel of sound thf'
dncibp.l has been devdopr.d as a quantity
unit. This measll('(!ment is commonl~' 1')(-
prpssecl in (;onnec,lion .with a l'illlIW of
wave Ir~ngths ill lIf'rtz. TIH' loudl1f'!;s II!
sounds is 11~(!aslll'f'.! from 15 df!cilH'ls fill'
the avr.ragl~ thrf'sh(,Id of )waIillg 10 140
decibt'ls for the thr,'shold of pain.
Glossary of Terms
Density: The ratio of the mass of a specimen
of a substance to the volume of the speci-
men. The mass of a unit volume of a sub-
stance. When weight can be used without
confusion, as synonymous with mass, den..
sity is the weight of a unit volume of a
substance.
Dust: Small solid particles crea ted by the
breaking up of larger particles by proc-
esses such as crushing, grinding, drilling,
explosions, etc. Dust particles already in
existence in a mixture of malel'iills may
escape into the air through proc(:ssing
operations.
Dust CalIedor: An air cleaning clevic!: to re-
move heavy particulate loadings from px-
haust systems bdore discharge to out-
doors.
Emission: Releasl! into the atmosphere of
contaminants.
Fumes: Small solid particles formed by the
condensation of vapors of solid materials.
Gravity, Specific: The ratio of 1 he nH1SS of (J
unit volum(: of a subslanc(! 10 tlw mass of
the same volunw of fl standard suhstance
at n standard t(!m(Jerflture. Water at 3\1.2"
F. is the stflndard substance usually re-
ferred to. For gas(!s, dry ail', at the same
temperature as the gas, is often taken as
the standard substance.
Hertz: This quantity has been flccppted as
the unit for frequency. Numerically onr.
Hertz equals one sound wave cycle per
second.
l8
Humidity, Absolute: The wdght of wfltcr
vnpor per unit volume, poLinds pI:r cubic
foot or grams pCI' cubic centinH-~tl'r.
Humidity, Hclo!ive: The ratio of thl! actual
partial pressure of the water V8!1or in i1
-------
space to the SiJtul"i:t!lOn preS9ure of pure
'Nater at the same temperature.
Inr.1! of Watp.r: A unit of pressure equal to
i t!II' prl'ssurp. exerted by a column of liquid
water one inch high at a standard tem-
rwraturp..
MfJ/lometer: An instrument for measuring
pressure; essentially a U-tube partially
filled with a liquid, usually water, mer-
cury or a light oil, so constructed that the
!1mount of displacement of the liquid in-
dicates the pressure being exerted on the
instrument.
Mir:ro/l: A unit of length, the thousnndth
part of 1 mm or the millionth of n meter
(approximaldy 1/25,000 of I1n inch).
Mis[s: Smnll droplets of materiol9 thllt lire
ordinllrily liquid nt normal tr~mperature
olld 1';'I~ssurt'.
PfJrU, irlk M,,!fer (lr Portie/II: As rdllll~d to
pollution control, nl1Y materil\l (~X(;(!pt un-
cnmhillf'd watcr, Ihllt exists us II solid or
liquid in the atmosphere or ip a Ras stream
!It n stnndaru conditions.
Pilot Tuhe: It consists of two concentric
tuhcs, one 10 measure the tutal pressure
cXlsting in the nir stream, the other to
measure the sUllic pressure only.
Pollutonl or Contaminant: Any solid, liquid
or gaseous matter in the outdoor atmos-
phere which is not normally present in
natural air.
Pressure, Atmospheric: The pressure due to
the weight of the atmosphere. It is the
pressure indicated by a barometer. Stand-
ard Atmospheric Pressure of Standard At-
mosphere is the pressure of 29.92 inches
of mercury.
Pressure, Static: The potential pressure ex-
erted in all directions by a fluid at rest.
For a fluid in motion it is measured in a
direction normal to the direction of flow.
Usually expressed in inches water gauge
when dealing with air. (The tendency to
either burst or collapse the pipe.)
Process Weight.: The total weight of all ma-
terials introduced into a manufncturing
process which may result in emissions.
Liquid and gaseous fuels and combustion
air are not considered part of the process
weigh t.
SmoKo: An nil' suspension (aerosol) of par-
ticlos, usually bu t not necessul'ily solid,
often originating in a solid nucleus, formed
from combustion or sublimation.
Vapor: The gaseous form of substances
which are normally in the solid or liquid
state and which can be changed to these
states either by increasing the pressure or
decreasing the temperature. Vapors diffuse.
19
-------
APPENDIX II
CONVERSION FACTORS
LENGTH:
Given Units Desired Units Factor Multiply By
Inch Meter 2.54 x 10-2
Inch Centimeter 2.54
Inch Millimeter 25.4
Inch Micron 2.54 x 104
Meter Inch 39.37
Centimeter Inch 3.937 x 10-1
Millimeter Inch 3.937 x 10-2
Micron Inch 3.937 x 10-3
AREA:
Given Units Desired Units Factor Multiply By
Square inch Square centimeter 6.452 x 10-2
Squurl~ inch Square meter 6.452 x 10-4
Square foot Square centimeter 929.0341
Square foot Square meter 929.0341 x 10-4
Squnre centimeler Square inch 15.5 x 10-2
Square meler Square inch 15.5 x 102
Square centimeter Square fool 10.764 x 10-2
Square meter Square foot 10.764
VOLUME:
Given Unitli Desired Units Factor Multiply By
Cubic fool Cubic meter 2.8317 x 10-2
\'uhic fool Cubic r:(~nlimeler 2.8:117 x 104
Cubic foot Liter 28.316
Cuhic inch Cuhic melm 1.f13872 x 1 O'~
Cubic inch Cubic c(mlinwlt~r I n.3872
Cuhic inch Li Ir~r 1.638G8 x 10-2
Cubic mp!1'1 Cubic fool 35.314445
(:llhic nH'tn Cuhic inch 6.1023 x 104
Cllbic cf!nlimetl'r Cubic foot :1.5314 x 1O-~
Cuhi(' (I'nti.neter Cubic inch G.1023 x 10-2
I.i tf~r Cubic foot 3.5316 x 10-2
2l) I.i! I'r Cubic inch 61.025
-------
vvt;lGHT:
Given Units
Desired Units
Factor Multiply By
Milligram
Milligram
Mil1igram
Milligram
Milligram
Microgram
Microgram
1\ 1 iCrrJgra m
1\1icrogram
Microgram
Mir:r()grdll1s/cllbic meter
I\licr()grams/cuhic meter
I\lir:r!J,~rall1s/cllbic meter
Micrograms/cubic meter
I\lilligrdllls/clihic meter
I\lilligrilll1s/i:uhic meter
I\lilligr,lIlls/clibic meter
I\lilligr,IIl1s,'clibic nwter
(;I',II1lS, "1I1,ic l!Jot
Cr,lIns/clihic fnot
(;I'oIIl1S (.Idllc Illot
r;r,IIl1~: l(.Id1ic f'lot
Lhs,! I,I)()() clIlIIC f,~!'t
I.hs" I,()()() clihic 1"'1'1
1.11.';.11 ,I)()() I.lIhic r"l~t
I.h';, , I ,IIO() , III,ir: 1""1
(:,. ,illS "Idll' 1'11111
(.101111', (.Idlll 1,1111
(:, ;1;11'; CIlIIII: 111111
(:1,1111'; '(.Id,ic 11101
Gram
Milligram
Microgram
Grain
Ounce
Pound
Milligram
Microgram
Grain
Ounce
Pound
Gram
Microgram
Grain
Ounce
Pound
22.857 X 10"""
1.4286 x lQ--4
64,799 x 10-3
64.799
64.799 x 103
437.5
62.5 x 10-3
28.349
28.349 x 103
28.349 X 106
7,000
16
453.59
453.59 x 103
453.59 X 106
15.4324
3.5274 x 10-2
2.2046 X 10-3
1 X 103
1 X 106
15.4324 X 10-3
3.5274 X 10-5
2.2046 X 10-6
1 X 10-3
1 X 103
15.4324 X 10-6
3.5274 X 10-3
2.2046 X 10-9
1 X 10-6
1 X 10-3
1 X 10-3
2.8317 X 10-8
6.243 X 108
4.37 X 10-4
1,000
2.8317 x 1O-~
6.243 x 1O-~
4.37 x 10-~
3.531 X 104
3.531 X 107
2.2046
15.43
1.602 x 104
1.602 X 107
453,59 X 10-3
7
2.288 X 103
2.200 x 1011
O,47!J!J x 10 ~
14.286
Groin
\or,lill
Craill
Crain
Crain
Ounc/")
OUllce
OIlIIC(~
Ounr.(~
Ouncf'
Pound
Pound
Pound
Pound
Pound
Gf!lm
Cram
Gr;'Jl',
G ,11
Grilm
Ounce (avdp)
Pound (avdp)
Gram
Milligram
Microgram
Grain
Pound
Gram
Milligram
Microgram
Crain
Ounce
Gram
Milligram
Milligrams/r.ubic meter
Grams/cubic foot
1.bs./1,OOO cubic feet
Grnms/cubic foot
Micrograms/cubic meter
Grams/cubic foot
1.l1s./1,OOO cunic feet
Grains/cubic foot
Milligrams/cubic meter
Micrograms/cubic meter
Lbs./1,OOO cubic feet
Grains/cubic foot
Milligrams/cubic meter
Micrograms/cubic metP-f
Grams/cubic foot
Crilins/cllhic foot
Milligl'ilms/cubil~ mpt(~r
Microgl'illl1s/cubic mel(~r
(;rilll1s/clihic fool
l.hs./I ,000 cubic feet
-------
Correction factors for Temperature of 1 Cubic Foot of Air
Factor to Calculate Volume of
Air Flow in the Hot-Mix Plant
System [cubic feet per minute)
Temperature In
Degrees F.
-50°
-25°
0°
20°
40°
60°
70°
80°
100°
120°
140°
160°
180°
200°
225°
250°
275°
300°
325°
350°
375°
400°
450°
500°
550°
600°
650°
700°
750°
800°
900°
1000°
Examrln: If
-------
BIBLIOGRAPHY
Guide for Air PoIlution Control of Hot Mix Asphalt Plonts; Information Series 17; National
Asphalt Pavement Association.
Air Quality Criteria for ParticlIlatv Motter; Public Health Service; U. S. Depu1.tment of Health,
Education, and Welfare; 1909.
Control Techniqucs for ParticlIlufe Air PoIlutnnts; Public Health Service; U. S. Department of
Health, Education, and Wdfare; 1969.
Control Techniqlles for Sulfur Oxide Air PoIlutants; Public Health Service; U. S. Department
of Health, Education, and Welfare; 1969.
Fed!)rol Pol/ution Control Programs: Water, Air, and Solid Wastes; Stanley E. Degler and
Sandru C. Bloom; The BIlr(~,lU of National Affairs, Inc.; 1969. .
Sto!!) Air Polllltion Conlrol Lows; Stanley E. Degler; The Durl~au of National Affairs, Inc.; 1969.
Air Qllldity CritvfI(J for' Iydrocor!)()ns---Slllnllwry und Conclllsions; Public Health Service;
tJ. S. l)Ppartn1f~nt of 1I1'1I11h. Educalion. and Welfare; 1!J70.
Air Qllulity Critl!rio for Sulfur Oxid(!s-SlImmary and Conc:lusiol1s; Public III!alth Sl~rvice;
! I. S. Ikpartnwnl of Ilt~allh. Education, and Welfare; 1!)69.
/\ir Quolit}' (:rit('rio for Corhon MO/loxilk--SlIl11l11ary ond Conclusions; Public lIealth Service;
I J. S. Dl'lJIlftlllenl of !l1),lIlh, Education. and Wdfnre; 1\"170.
1''''I',,;'r/(]l Vvnti!ufioll; !Jth Edilion; Anwrican Confnrenc!) of Covernm()nt Industrial Hygienists;
! I)().
Atnwsplwr/(" SlIrvey Troining COllrs(! Mnnunl; Public Health Service; U. S. Department of
Health. Education, and Welfare; H1B4. ,
/Just Control Tl'chnology /lnt! th(~ Crush()d Stont: Prot!uct:r; National Crushed Stonl) Associa-
tion: 1~)l.m.
/)l/sI Pollution !\1t:osllrClr1ent ns Applied to Thf) Crushed Stont: Industry; National Crushed
Stone AssoCIation.
Pror.edllre for fkterrnlflntion of Velocity nnd Gas Flow Hatl!; Publication No. E-P 2; Industrial
Cas Cleaning Institute, Inc.; 1965.
Mf)thods for Determination of V()locity, Volume. /Just and Mist Content of Gases; Bulletin
WP-;,(); Sixth Edition; lay Manufacturing Company, 1000 West Ninth Street, Los Angeles,
CJ!ifnrnia 900"15.
Te~;t pf()CI~dllre (or Gas ScruhlJl'rs, W(!( Collectors Division: Publir.ation No.1; Industrial Cas
Clf'aning Institute. [nr..; EH;4.
"Terminology
-------
ENVIRONMENT AI.
CONTROL
COMMITTEE
Co-Chairmen
JAMES DENTON
W. CON PROCTOR
Members
Arthur Molzan
Richard J. Bartell
Clifford J. Heath, Jr.
Carroll Jackson
Wesley Davidson
Louis Dickie
Milton F. Masters
William Rudy
Thomns Rp.inhnup.r
Dean Chp.rry
Lansing Tuttle
John S. SpanglP.r
Chnrlp.s L. Mniflch
John Gray
Fred Kloiber
Director of Environmental Control
-------
KRAFT
PUl PI NG
The pulp and paper industry, which is the
fifth largest industry in the United States,
produces approximately 400 pounds of paper
products per person per year.
Manufacturing of paper and paper products is
a complex process which occurs in two distinct
phases: The pulping of the wood and the man-
ufacture of the paper. Due to the complexity
of the processes, the twu phases of the wood
is chipped, digested, washed, bleached and
thickened (see flow diagram 1). The pulp is
then sent to the paper mill where the pulp is
heaten to break up lumps and the resulting slurr
sl, rry is then screem'd. Dyes and fillers are
t I " ,Id ded to the pulp and thorough1 y mixed.
,.' treated plIlp is then spread on a traveling
belt .Ifld fin.lily put throujO\h a series of rol-
ling processes to squeez~ out excess water.
There an' four major pulping techniques: (1)
kraft or sulfate, (2) sulfite, (3) groundwood,
and (4) soda.
Of the two phases invoLved in paper-making
the pulping process is the biggest cause of
air and water pollution. Of the four major
plll ping te,'hniques the kraft or sulfate pro-
cess produces over half of the pulp produced
annually in the United States.
DESC~D'TlON OF
TII,[- ,K_RAF~}':"~~ING PROCESS*,
I'u 11' \-c'd with wood ('hips
[,I d large. llpri~ht pressure vessel, known
oJs a digester. and couked for about 3 hours
wIth ste,lm ;1t .1 gauge pr"ssure of approximately
llO pounds per sqUi1!'c inch.
!Juring the ('(j('klng pprlod the digester is
f\" 1 i eved p" r iod1c,j 11y lo redu('e the pressun>
build-up of varlo\l,c; ~~:JS(,S within.
\.JIJ('n c()okin;; is (,olllpl,.teJ, the bottom of the
digester Is suddl'lIly opened, and its contents
forc'ed Int.o tl1<' blow tank. Here the major
PROCESS
portion of the spent cooking liquor containing
the dissolved lignin is drained and the pulp
enters the initial stage of washing. From the
blow tank the pulp passes through the knotter,
which removes the chunks of wood not broken
down during cooking. It then proceeds through
various intermittent stages of washing and
bleaching, after which it is pressed and dried
into the finished product.
A major reason for the economic success of this
type of pulping operation lies in its ability
to recover most of the chemicals from the
spent cooking liquor for re-use in subsequent
cooks. The recovery process is inititated by
introducing the spent ("black") liquor from
the blow tank into a multiple effect evapora-
tor where it is concentrated into a mixture
with a density of about 25° Baume. The spent
(or black) liquor, is further concentrated in
a direct contact evaporator, which by bringing
the liquor into direct contract with recovery
furnace flue gases, evaporates an additional
portion of water.
The combustible, concentrated, black liquor
thus produced is then forced through spray
nozzles into the recovery furnace, where it is
burned to recover a portion of the heat by
oxidation of the dissolved lignin and to con-
serve the inorganic chemicals, which fall to
the floor of the furnace in a molten state.
The resulting melt, which consists mainly of
a mixture of sodium sulfide and sodium car-
bonate, is withdrawn from the furnace and
dissolved with water and weak liquor from the
cau5ticizer, where the sodium carbonate is
converted to sodium hydroxide by the addition
of calcium hydroxide. The calium carbonate
resulting from the reaction precipitates from
the solution and is collected and introduced
into a lime kiln, where it is converted to
calcium oxide. This is slaked to produce cal-
cium hydroxide for further use in the causticizer.
The effluent solution produced by the caust-
icizing reaction with the green liquor contains
soldium hydroxide, sodium sulfide, and smaller
quantities of sodium sulfate and sodium car-
honate. Known as "white liquor," this solution
Is withdrawn and re-used in the digestion
process.
Conslder yourself the resident engineer of a
pulp paper company operating at 75% capacity.
Your recovery furnace is emitting the follow-
ing load of pollutants:
1',\ . (:, pll'. ] Oil. " . /'J
*R"prlnLcd I !pm 1'l1vl rtHur,enLll Health Serles No. 999-AP-4
-------
Kraft Pulping Process
Particulate 42 tons/day
Hydrogen sulfide 950ppm
Methyl mercaptan 950ppm
Dimethyl sulfide l25ppm
Sulfur dioxide 1 ppm
Flue gas 50,000 efm
What are your first recommendations in controlling the above unit?
RECOVERY FURNACE EMISSIONS
ESTIMATED)
Emission:
Pollutant:
10 to 40 tons/day
- - ~-----------
Particulate
Particulate
Hydrogen sulfide
Methyl mercaptan
Uimethyl sulfide
Sulfur dioxide
100 to 400 lb/ton of pulp
130 to 935 ppm
60 to 1,400 ppm
125 ppm
1 to 350 ppm
. - - -' .---- -----
2
-------
Kraft Pulping Process
PULP
wOOD CHIPS
RELIEF GASES
<.) <.)
~cz
V'\z-
~«~
~ 0
"" <.)
<.)
>- zc~
V> :.;:
UJ IZI U
() VI«U
« « «
~ w ....
0 ..J V'\
<0 ~
o «
.... w
V'\ ....
« ..,.,
<.)
w
::>
..J
KNOTTER u.
FReSH
MA ~E UP
LIQuOR 0.: STEAM
0
::>
a
-' 0.:: W A T ER
wO
'" -'....
nee U ~« DIRECT
0 ~ .... 0.:: CONT ACT
::> -' -'0
0 ,0 :J(l. EVAPORATOR
~~
-' :..:: '>
t..u .:{ UJ RECOVERY
w
>-- ~ STRONG BLACK
T UQ UOR FURNACE
>
CAUSTICIZER
TANK
GREEN LIQUOR
DISSOLVING
TANK
SlA KER
THE
KRAFT
PULPING PROCESS,
'\
-------
CONTROL OF PARTICULATE EMISSIONS
FROM LIME PLANTS-A SURVEY
l. John Minnick, G. & W. H. Corson, Inc.
r:rinted with the sped a1 permission oi AreA Journal,
Vol. 21, No.4, April, 1971
-----~_. ---
LilliI' hll,'" 101'('lIn\l' Ih!' \\'orld's h'adin~ I'rl\,j!;PIlt. for use
ill t.ill' trf'at.nll'llt of bot.h wat.er !tlld air pollut.ion and,
afkr sulfuric I\\~id, i,.; tll(' No, ~ Imsic ehrmicn.[ ill com-
1JI('I'I'ild \1SI'. A,.; 1\ 1'1''';lIlt, 1.11(' pl'oductioJl eapacit,irs of
t.hr III an II fad IIrin~ plant,s al't~ bpilljl; mpidly I'xpallded to
IIH'I'1 t.h,' illl~I't'!\,.'iilljl; dl'lnllnd for lilllillf,!; IIwl.pl'ials.
This papl'r (Jpseril)('s 1.1\1' !t(:hi/'v('lIIl'nts or Ihp JinH' iJl-
dustry in devl'lopilljl; md,ilods of handlin!!; and COIlt.ro[-
lill!!: t.hp various li/wly divid,'d produet.,.; whieh th'y pro-
rluel'. An I'xtpnsivc sllrvl'Y providt.,.; IIsdul dat!t 011 the
IwaiJahiJity and pel'forJllalicc of III:IIIY of the control
dfvieps that aI'(' currl'nt,l.y iJl IISI', 11Iid an ana[ysis is
madl' of t.hl' op(~I'at.ing dlici"IH~i,',,; alld Co,.;t,.; of t.his
I'ljll ipml'n I.. Thr t'livironlJ1\'ntal cont.rol prol!;mms
whidl 1\1'1' CllIT('nt.!y IInd('rwny in thi,.; indu,.;t.ry are dc-
,.;('rill('d and :III ('valuat.ion is m:uk of t h(';;e pro~n..nH.
Thl' ult inmt" jl:oah< I.hat. :\1'(' !H,lil'vl'd t.o be at.t.aillablp
are pl'(';;I'IIII.d 1'1'11111 till' ,.;1.Hlldpoilil of I'lIli;;,'iioll cont.rol
from individllal pl'o('p,'ise,.; as wel! as from operat.ing
plant e()mpkxI~s. While t.he pl\p('r rlcals primarily
wit.h pract it'1I1 olwrnt.injl; and enginct'rinjl; aspects of the
Hubj('cl, ";'HlH' informat.ion is also included on methodi:'\ of
(pst.s IInd t,h,' ll1onit.orin~ systems that aI''' in IIAe.
Dr Milllli.,k is Htmi"r Vioo Pn'Hi,lnllL of U. & W. !I.
el/rS';II, Inl'. Plymouth MOI,tillP;, 1'/1.. 10462.
April 1971
Volume 21, No.4
Repr/..ted from APCA JOURNAL, Vol. 21, No.4, April, 1m
ill
PA.C.pm.l07.5.73
'I'IH' malluftt!'ture of limp, in America has been expanding
during r..eent yeRra t.o ml~et the KTowing demands of thOBe
indust.rip'A iuvolved with the control of air and water pollution.
Limp, slurri(~s have he!'!n used for years in the control of stack
J.!:Hsrs pnrt.ieularly for t.he removal of 802. Currently there is
interl'st. in the injection of IimeRtone into coal and oil fired
hoill'rH for the Harne purpose, In the field of water pollution
eontrol thpre are over 2000 munieipalities in the United States
who are using lime in their treatment plants. More than 50
t.YPPH of i!1dustrial waste watcr are effectively controlled by
t.hc usP, of this reagent. These include such applications as
st.ccl waste pickle liquor, metal plating wastes, cannery wastes,
wash water from chemiral and pharmaceutical processes,
IllundricR, petroleum refin!~ries, etc. Recently several plants
have heen put on stream which are suceeS!!fully removing
phosphateR from domestie water wastes with lime treatment.
The inerease in demand for lime has required a substantial
modification in the operations at many of the manufacturing
plan ts. I n view of the fi ne particle size of lime products, the
industry hus found it necessary to install equipment that can
effectively handle huge tonnages of these fine powders. In
addition, the control of particulate emissions has received
a great deal of attention.
I I, is well known that the particulate emiB8ions from a lime
plant are not injurious to human health but they can be
c()!1sirlered to be a "dust. nuisance" to the community. A
previous paper of the TI-2 Committee' describes the lime
imluAtry's prohlem of airhorne dust in BOme detail .and alBO
provides Borne hasis for the emifl!lion potentials of BOme of the
I~quipmcnt found ill limeHtone processing, in lime burning,
I\nll limc hydration operationA,
I II ol'(h~r to provide t.cehnienl illformatioll on the control of
pl~rt,iculltte emiBMioliB in lime plnllt operations, the National
Limo ASHocia!.ion Pure Air Committee has recently conducted
IUl l:xt.clIsive l:Iurvey of I~ lIumber of lime manufacturing plants.
The primary purpose of thil:l paper is to provide the results of
this survey together with some observations that have been
made from the findings.
-------
U nfortuna.tely control of particulate emi88ions from lime
plS.'lts is a complex subject, not only because of the diversity
.}f the manufacturing processes used in the different plants,
but because of the variations in control concepts that have
been adopted by the plant engineers. A small lime plant
which may not have rotary kilns can have entirely ditTerent
emi.eBion problems than is the case with large operators who
may have one or more rotary kilns. Some plants employ
wet processing techniques whereas others use dry methods,
and the newer plants may also be in a better position to
utilize central system dust collection where this may be com-
pletely impractical for plants that have been established years
ago.
Survey Findings
Twenty companies responded to a questionnaire circulated
by the National Lime A880oiation Pure Air Committee. The
results of the survoy are presented below in five seotions, each
of which repre~ents a major segment of 8. lime plant operation.
InIKHI'" ILreas the information available is quite limited; how-
ever. : n I,ther segments of the operation muoh more is known.
It ib .~xpcctcd that as supplementary information becomes
availahle this report will be revised to keep the 1'1-2 Commit-
tee informed of significant progre88 in the lime industry's
environmental control programs.
Qu.rrylng
With proper plnnning of the quarry operation, this se~-
ment of lime production is not a major source of particulate
emission, and etTective control has been accomplished in
many plants. Some of these procedures are outlined below.
Stripping Operations. The removal of the overburden, by
the use of various earth moving equipment, usually results in
large areas of bare or denuded soil exposed to the sun and ~ind
erosion. The primary purpose of the control method IS to
retard the removal of moisture and to reduce the rapid move-
ment of winds over the areas. This has been done by the
construction of berms, by planting of suitable ground covers
and windbreaks, erection of temporary fencing (snow fence),
and the minimum disturbance of natural vegetation. Re-
sulting spoil banks can be contoured and planted with suitable
cover. The local county extension agents and state and fed-
eral conservation p;roups otTer excellent advice and give valu-
ablo assistance to the operators in this respect. Examples of
plants which perform well include crownvetch, multiflora
rose, and hybrid poplars.
The final cIeaninp; of the stripped or bare rock, exposed by
the strippinl/; operation, has been done by hand or meohanical
swooping of the surface. The developmcnt and use of a
oommercial mobile mounted vacuum pickup system has been
suggested for dust controlnnd final cleaning.
Primary Drilling. Thl1 prime source of dust from rotary
and percu88ion drills ul:linp; compressed air is closely confined
in II. small area. Various manufacturers have diverse selec-
tions of equipment to control effectively dust at this source.
The most frequently used are mechanical cyclones. Bag
type collectors are also available. Some states have ma~e it
mandatory to equip the drills with dust control d~vlCes.
Figure 1 shows equipment used at one plant. OccasIOnally
water with a wettinp; agent is effective.
Primary BlaBting. The control of airborne contaminants
from primary blalltinp; is closely allied wit.h jl;ood ~olltrol ~f
blastinp; practice. Th(~ initiation of dctolln.tlOn wIth mu~tl-
dIJlay devices and t.he complete combust,101I of the explosIve
comroUlHI!\ durill/( a wcll planned "shot," or "hlast" results
in low clul:lt emission from primary blastinp;. The explosives
mnnufl\(~turerB give excl,lIMt technical aB8istance for each
operation's special problems.
Secondary Htallting or Brmkufl6. Tlw l:Iocondary blasting
OIN'rnt,ion in many qun.rricH ill IIOW either elimillllted by better
i;v
Figure 1. Dust collection device used on querry drill.
fragmelltatioll durillg primlu'y hlat
-------
_r~
--,
. 'J;.~T:)
- 0'.' ...,-
Con..merciill vitCUlJm sweeper.
~11I'1,,,,,',illg II", dll,t I" :dl"II."",' 1111111., 1\'11.11 1':tglt"I1~",~,
, .d'IH'I'~, "I' ,'\'('I"""-~"l'Id"H'r ,',,"d'llllIli"II'. III t.l1" 1:Lu.(~r
('IL""',"; ('lliclt'III'lt''''' :lrt' rt'poJ't,l'd of ~IS.J( ;1 alld :11)(1\ I'
!\l,,~t pl:lId~ II'" PI'II":tI')' ,',dl"..I"I'~, ""11'1...1.11'1-< "r dllsl.
,.IIIIIIII"'rs 1111,);',,1' ,.)'..I"II"~, "'11.1:(' killls I\'lt.lt dli..i"llt'i,'s !'allg-
ill" from ~fj I" ,,,O',~.;,, Tit"". w('n~ r"II"I\'('d hy s(,""lIdary
('"I1,...t"r... :I~ 1',,11,,11 s:
( ',\ ('1"11'"
\Vl't s"l'Ilhlll'l'....
I \ag,lt. "''''.,
EI,...ln(':,11"."..il"I:tI"1'
N" --'1"'''",)11.1')' ,.,,11""11<)[1
~o kd,I'
:is "dlls
II klilis
I ktlll
S klilis
:-;"'"1' "r nil' prlllI!('lnS ass"..iiJl,'d II iU, II", ""Id.rol "I' '~lIIis-
SiOllS I'nlln kiliis l,av,.I,"('n /'1'1'"1'11',) as'
1. /)1'--'1'0,,:01 "I' dlht. ""II""t,.", !\I"sl "\I,,'dit.i"II' .I "IH)Sal "I'
dry dll.,1 froml'a).!;h"IIS('.'4 is hy "'1'('11 """I"'Y"I' 1'1'''1111 '1(' h"pp",r
t" a p"("'lIlItti(' """VI')'llig, ....)':-;1\'111 I" 1'"1 "' ,d". l'()w I iIII-!;
1111.1 l:tg'''''';II).!; "f ('"llt-d.I',) dllst 1'1'11111 1\'", s\'I'ld>l!:.! "I' rell"r of
nil' alkaltlll' wat"I'.
~. W"lIr and 1('1l1' "II "I~II "Iq' l('il.y SIIlITY 1'"llipilig ('qillp-
II 11'11 t.
:1 I )lsapp"lId ;IIg,ly ..dl"l't. I'll!/. iiI',. "r It-~., t It:w II )"'111'.
~. J I1l\h IIIJI':t~ioli 1\1111 "OIT<>SIIJI. dllm~I!/." t" filII illlj"dlt,I'S IInd
dallll"'/'"
It WitS observed from t,h" reportH returned in the survey
that both scrubbers and ha!!;houst's, If properly designed and
maintained, have demonstrated hi!!;h dust removal efficiency
that should mcet E.trict rcquirements. However, ber.ause of
the high operatin!!: and maintcnancc costs for these, electro-
static precipitators have evolved new interest. Their higher
cltpital costs may he more than offset by their inherently
lower operatillg alld maintenance costs. Finally, it was
cvidi'nt t.hat no cyclonic method alone would he able to meet
striet dust emission standards, A generalized p-stimate of
eosts f"r t\w various typi'S of eontrol equipment for a rotary
killl at two t'fJieiency levrls is ineluded in Appendix I which
also pre~ents more dctailed information on the control equip-
ment 011 lime killls.
Lime Hydration and Orlers
TIH' hydration of lime and hydrate bagging present a poten-
tial d list problem, alt,hollf!;h cxisting methods of control /1,ppcar
ad('qlllltc ill solving thc pr"blem. The main source of concern
is the puhlic reaetion to the steam plume which cannot be
rcadily pradicltled.
'i'll{' t.ypes of r.ollt,rols uormally u~ed in hydrators con~ist of
t,lu:foliowing:
I. Wat.t'1' sprays ill hydmtor staek. Dust pllrtie!e~ lire
cllt.mplwd hy spmys alld 1,1H~ resulting Hlurry or milk-of-lime
i~ pip('d (,Ilek to the hydrator's pre-mixer as part of the slaking
wllter. Limc losses are averted. Virtually all effirient
hydrator:-; have this "'ljllipnH'nt intcgmlly installed. Wet
eyeloll<'s or a "mall wpt St'.ruhber may be used instead or
as /1, :-;lIpplement to :-;prays. Most of what is vented is steam
from thp h'~at of hydratioll,
2, Cye!"lIi<: pr!'-dealling may he performed at all transfer
poillts ill tllt~ hydmt.ion ~YBtem, like the conveyor, elevator,
qui<:klime /.!;rilldt'r and scr<:ell, air classifier, milling, and bag-
ging. This plirtially reduces dust load, but further dust
redlldioll i~ lIee(,:-;sary. Individual dry cyclones may also be
cmploy,'d at a specifie loeation.
3. Emi~~iolls from a (:yclonie pre-cleaner are usually vented
int.o a bllghouse or small independent bag filters may be
opemted at s!wcifie loc/1,tiollS, like bag paekers. Bag filters
are "ften /1,n iute/.!;nd p/1,rt of packcrs. Hoods are also em-
ployed at baggers to cOllfine dust.
()n(~ ,'.orrIJ'/1,IlY that m:tkes several types of hydrates em-
ploys six separate du~t l'ollection units: two wet cyclonic
collectors conllcded with hydrat.or stack; bag filter for Ray-
mond Mill; serubl)('r to cOlltrollime pumpillg to storage tank;
tllll"('[ ('"lIpc[.or; iwd a bllg ('ollc(.tor for qllirklimr grinding.
TlwlI, thpy used t.lJr("~ hag lilt",rs in t.heir t.hree blt!-(gin/.!; mu.-
(:hint':-;.
Table!. Ston(' pI \)CL".'.HI~
Cloth area No. 01 com-
1'1.."t Collo(I,on PO/Ilt" Airflow sq It No. of bags partmonts Type cloth Installed cost
8all Mill 10,000 elm at
80"F 1480 $19.000
SPC. Crll~llIn..: 11.000 cfm at
drld SCr('pnin~ 14 in. H,O 3600 64 4 Dacron
f'/"Y/llond Mill 4000 elm at
(, ,14 tn. 1-1,0 1830 332 Glass
(2) lbll' M,II 2000 elm at
6 in. H,O 1320 32 Glass
~ rl'bblo Mill ~OOU cfm at
Hin,I!,O 2592 216 Sateen
8,,,dley Mill 6000 elm
Raymond Mill 1000 elm
. Indud,n!! as_Of Idlod feeuN, ek '-I"lnr. screens, and belts, One plant gave dust loading figures as 53.8 Ib/hr at 150°F for the Raymond Mill;
lllb/hrfil13~oF fortl,e tuln: 111111. 48,b/I"Ht 160"1' allheconveyor.
Aprlll'!?1
Volume ?l. No.4
197
-------
Tabl.lI. Hydrators
No. of
Filter erea, No. of compart. Capital and
fype of system Air flow cfm sq ft Air-cloth ratio begs ments Installed cost Type of application
Ball filter 13,000 1750 128 19,000 Bagging
Ball filter 11,000
(5 In. w.g.) 9660 112 30 ,000 Fines from cyclone
Bag lliter 1668 3.55:1 9,500 Fines from pre-cleaner
Ball filter 5,000 1050
Balllllter 10.000 3 30,000 Bagging
Ball filter 14,850
Bag filter 4,250 43 Bagging
Bag filter 6,000 576 Bagging
Bag filter 5,000 1050 10 ,000 Quicklime grinding
Bag filter 2,500
(150. F) 344 16,000 Raymond Mill
Scrubber 9,500
Cyclone
pre-cleaner 10,000
Bags used are cotton, dacron, and glass; decron most common,
Tabl.. Driers
No. of
Cloth area, compart- Capital and
Plant Collecting system sq ft No. of bags ments Airflow, cfm in stalled cost
Cyclone end baghouse 2550 360 15.000 at $10,000
220°F Cyclone
36,000
Baghouse
2 Baghouse 6250 112 4 4,500-7,500 20,000
at 12"
Primary, secondary
cyclone, and 18,100 at
baghouse 3120 312 8 2300F 50,000
Cyclone (only) 8,800 12,000
2-Stage cyclone and (400 gpm 50,000 at
high-energy scrubber H,O) 30" 215,000
Efficiency
99+ %
(508 Ibl
hr)
99.9%
Tllhle I I j!;ives (h.t.llil~ of tlH' stat.lst.iealn'sults outuilled,
Dril'rs rl'prl'Sl'lIt, with the possihlt, I'xreptioll of rot,ary
killls, t.h(' lI!ost diffi(,ult dU8t eOIlt.rol opemt.ioll ill It lime or
lim('stoIH' plllnt. For me!'hlll{ striet emission stftlldl1.rds it.
app('lIrs Lhllt. primary ('yelon!' eo!\ectors follow!'o hy hag-
houst's as s!'rolloary are nlmost, mlludatory. Tab!!' III ,ll;ives
the fil{ur!'s obtailleo.
Fugitive Dust
The first Ic!{islnt.iv(' hody Lo (jpvelop re/l:l1ll1t.iolis whiPlI lire
speeifieally dir('eted t,o fu~itiv(' dust ItS !'mitted from plant
operations, such as t.h(' lime inoustry, is the Rtate of Penllsyl-
vania. The methoo of t!'st whieh is requiwo by this re,ll;ula-
tion is ba..seo on the use of a pOl'tab!!' !'Jeetrof!tatic prp('ipita-
1.01'.1 In monitorin!l; these cmissious, mcasurt'ments arc maoe
for ten minute periods dowllwiud of the SOUr('I' lit. It !oeatioll
outside of the plant. proprrt..\', A \'em!!;(' hlwk!!;ro\lI\d eon-
centrat.ions are also d!'tprmiu('d upwind of 1.111' plllill. The
pmission is ea\culatccJ oy Rubt met.iu/.( 01(' uJ>wiud from t.he
downwind read iIII/;. '1'11(' rp/l:uhd.IOII alRo sIH,,'ifips a limit, on
t.he st./Lek emissionR brlspd Oil !l;rollud Ipv('1 COII('('IIt.mt.ioIIS dlH~
to J>/lrt.ieulate fall (!{relltr'r 011\11 10 mier()I),') IllId ,~UHI)(~lId"d
ptLrti('ulate matter (I('ss I,hllil 10 mi('.rol\.~). (u vi('w of the
in(,reasill!l; ',relld to !'st.llhlish limits bUf!('d Oil t,lw total erniHsion
froll! n. facilit.y mU1('r t.h/lll Oil R('I)/(mtn ROUn'('R sllch aM Mtn(~kA,
t.ho lim!' illd'ust.ry haR also 1"'('11 nmkillp; ITIOaI!UrIHW'Iit.f! of
alllbi!'nt air OOIlC~IIt.f/lt.ionH III Lh(' v j,'init,y of thn pllwt!!,
A r('viow of tho Hlajor Homec,s of fU/l:itive dust. emif!f!ion in
lime plants ill present,ed below with Hpeeifie eommr.nts on
variuus procedures that aft' utiliz('d to rpduee tho contribu-
tion from these sources.
198
CurtaiLment of DU8t from Roads. The effect of traffic and
wind on dust whieh aceumulates on roads is a primary souree
of fu!{itiv(' dust.. Since tnany of the roads in the plant eom-
plex are tempomry, and may also be used at infrequent inter-
vals, nil of thr l'Oudways in the quarry ano Rtone processing
operat.ions ("11\1101. he covered with a permanent wearing
course. In t.hose eases where roads ean be paved, asphaltic
mixtures have been applitd over t.he hase course either as an
oil alld st.one chip eoverinl/;, 01' as a plant mix asphaltic eon-
erete wearilil/; course. The cost of installations p;enerally
ran!{e from $2.001 to $3,OO/sq yo.
The fl'lIIoval of dust from the paved roads is rarried out in
Reveral ways ineluding the UAe of street cl!'aninl/; equipment
such as hrush type ano va<:uum typP Aweppers. It has bpen
the experiplI<:(' of some of thC' operators that the Wl't brush
sweepPI' ll'aves 11 residual fillll of dust after th!' liurface dries.
A vl1ruum type sw!'epC'r, Aueh ItS that ml\l1ufllctured hy The
TC'llillWt, Compfwy or The WltYIIP Company, hils I)('pn founo
1.0 he quit.(. ,~n.t.isflLd.ory (Fijl;ul'I' 2).
nusl. ('ollt.rol from unpaved roads is universally a<:hievcd
I,y mealls of It periodic coverin!!; of oil 01' by ('hrmi<:ltl trellt-
1I1l'lIt. Home plants find that they c:nll utilize Wltste ('rusher
oil vf'ry eff(.(,tivety either lis-is, 01' hy dilut.ill!!; with small
amounts of dinsel fuel. The URe of l,hiR partieular method
I1III8t, t.ake ('ojl;lIizallcc of other faetorH Bueh ItS odor or Illaehinl!\
of the oil int.o adjacent streams, The m.t.r of applic/ttioll 01
oil is in t.hf' lIeiv;hhorho()(1 of 5 II:I.lloIlR per hlllld.'(ld square
yards of roadway. The mn.tcl'illl is applied evel''y otIC to two
weeks depelldillg Oil weather conditiolls, Where all asphalt
base material is used (lHO% asphalt), the coverage i'l about
half of that !{iven Itbove. This material need not be applied
Journal of the Air Pollution Control Association
-------
as frequently to the roadway. In addition, most plants apply
WaWr (with or without calcium thloride additive) as a supple-
mellt to the oilin/o; program.
Slockpile.~. . All inherellt part of lime pll.l.llt production is
the establishmt'nt of numerous surge stockpiles of limestone.
This is primarily t.ht' result of accumulatiolls of certain sizes
of stont' that may not be required by the market at the rate
with whieh oth('r sizes are utilized. Further, some of the
crushed limestolll' sizes are supphed on a seaHollal demand and
the producer II1l1st therefore stockpile in advance. Fortu-
nately nJOl:!t of thl'se lIIaterials can he st(wk pill'd il\ t.he 0JWI\
and may be kept. ill a moistellrd condil,iOlli'd. As lIIent.iolll'd
previollsly, W!\st.(' pil('s whil'h n'sult, fl'om o\'('rburden or ill-
eluAiolis of impul'l' St.OIlI' e.1l1i h('!\ probl(,111 silu'(, t.lli're is u'lIlIlIy
very lit.t.lf' d('malld for I.his t,~'pe of 1II/I.t.l'I"i:d. I'mdu!'\,;.; sill'll
&H ((I~iekliml' or h,l'dmkd lime aI'(' ahmys sl.(JI'I'd ill sl'lt!t,d
billA or siloA alld IIH'rdon' do "01. l'ollsl.il.llt.l' 1111 "I'xposl'd"
stock pill' problem.
Tbe IllduAI.ry bllA hl'('n rl'llAolI.lbly SIlI'C'I'SSflll III c'ont.I'ollill~
the ('miAsion of airborllc dusl. fl'ol!l st.oc'kpil('s ill s('\'1'1'II1 ways.
The II"St import.allt. is t.he wet.t.,,\~ dowll of t.he slm:kpiles Oil
a , ., ,"1\lin~ hllsis. This sllb~.t.alll,illll.l' n,dUI'I'A t.he rfff'd
of "1110 ('I"oHion. :\ phot.o~m;)h (Fijt;un, a) is prl'sent.ed
showinJ.!: Ihe t.y"..' of equipmcnt. that. IS bl'in~ uspd SU(.(.t'ssfully
for t.his purposl'. These are "pmy t.OWl'l'S approxilllllt.l'ly 40
ft hi~h t.hat. are equipped wit.h Raillbird lypp spmy nozzlps
capahle of spmying wat.er at the mtt' of 500 J!:pm. Tlw
unit. shown in th(' piet.urc ('all spn'ad a spray of watl'r in "
continuous. circk of a 200-ft rt;dius. It requirps but three
pas..'I('s t.o wet. dowlt t.he pile. For thosl' Il1lltl'rials which must
be shipped ill dry condition, t.he sl.ockpill's arl' pit.her kept
within suitahle enelosurcs, or an' rUII t.hrough a dl"ying process
at t.he till1!' of shipmellt. !'!'rmllllcnl wast!' piles or spoil
banks thnt. have hl'cn cov!'l'('d with plantinj!s arc I'!'porl.pd to
give adequat.e prot.('rlioll !l1/;H.inRt. wind I'rosion.
Propl'r locat.ion of st.ockpiles ,~all he IlI'lpfnl pllrl.iclllal"ly if
thev Ill'!' hdailld natllral (or IIlIlnufllt'lm'l'd) hllrl"il'I"R, s\II'h as It
hill'or Hlope of ~(round, It roll' "f 1.n'I'A, \\'lIld haf!ll's, 1'1t-. 'I'll!'
Ill'tiv(' or wOlkuII/; sidl' of II slnd,pill' IS lI,ualh' ('sllll>lisll!'d I.)'
consl11111 WIII,.y 11.'11'.1, pal"l,lI'lilarly fOI" till'
IraIlAl'lIl"t."I.11111 or ('onl"".I' lIVJ':n'I!.I,.t.('. ('III"I'('Iti. PI"II('t.II:~' ut.\IJZ('S
I'O\'('ril1~ of 1.111' 111:11,,1'1" I Wlt.h t.lll"l'aUIiI1S 01' Hpmyll1j1; Wlt.h
wale-I'. Th('HI' I'fllI'('.!II''''" /I"" 1I.;ulllly dll'l'd,'.! 1,0 t.ruek t.I'IlH!I-
pOI"t.at.ion "lit. of tit" ,.1,,:.1. "l'l'mUOII, \hn\lp t.nwkl:! cr('at.e
April 1971
Volume 21, No.4
Figure 3.
Rambiru spray towp.r~ wp,IHI1"~ stockpilp.s.
-- --
Figure 4.
tr.nials.
r.lo",ed pncum<1tu
-----
199
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Talale IVI Pneumatic Conveying Information
Pulverized Hydrated
limestone Quicklime 11m.
Capacity (t/hr) 9-12 10-14 10-12
Ranges of
horsepower 40-100 100-150 ' 20-40
Typical pumping
heights (ft) 4~O 55-75 45-65
Horizontal pumping
distance (ft.) 5~OO 55~50 300-400
Approximate
in stalled costs $30,000 $50,000 $12,000
a dnst prohle!\l in-pll\lIt whell tlJ('Y arc uspd to transport fine
sizes of dry matprial to ~llch points as stockpiles, 10ILdinl/:
hoppl'r8 for rail tTllII~purt, Pl<:. The most slIccessful control
for tl "51' types of 0p('m1.ion is t.o provide !'nclosurl's over the
dum 'I' ; area. TIl('sc enclo~llr('s may rl'qllire dust. (:ollection
eql. >l1\(,lIt to minimize par!.iclIlld<' cmissions.
A very importallt. rl'quirrm(,lIt for t.nwk Op(,flltOrH is the
limit of spe«.--d ill (and alAo Ollt, of) tlu: phUlI. 1"'(,!\Iist's. While
the lime plant has no ('olltro] of Lh(: drivI'r 01\('1' III' (clLveA the
plant, a strenuoils effort IlIlS ht'l'll ILpplil'd to keep srced limits
at II. low level. Within the plallt oprl'l1.t.iolls t.he limit is usually
postt'd at 10 miles pcr hour.
Miscellaneous. III additioll tn the items eovcred in this
report, fu!(itive onst can result from a \'lHicty of problems
within the plant complex. ~pi\lal!;r from overloadrd trucks,
lelLky bins, and the occlLsional breakin~ of bags are rxamples
of intRrmittent problems that need to be considered. In
jtcnt'ral, the ('ontrol of thcse devices is accomplishM by the
use of careful houskct:ping procedures. Control of isolated
situlLtions is only effective where t.he plant has a good sur-
veillance and educational profl;ram. The plants who are
attempting to do this have indicated that 8uch a pro~ram is
similar to the plant "safety" program which can only be
succcssful where a continuous on-going educational effort is
vifl;orously promoted by the plant management,
Resume of Survey Findings
The Hllrvcy 1111' ,hown t.hat many lilliI' plants h:1Ve heen
/l1,1(~ to control 1'lIIission cfTectiv(,ly to 0. degree that should
mert t.h(' dcmands of rPILsonahll: :, ir qll/llity standards. Home
of till' pllLnts JIlLl'" :dso pion!'('!'!',! in t.hl' control of rmiBRion
of °flll!;itivc dll'I," from fHICh SOllr('I'S as roadways, stockpiles,
transport rqnil '/lH'llt, etc.
i\. large vl~rict.v of eqllipn1l'nt IS in IIse throll/l;hout the in-
dustry to control emissions from th(: differl'nt process opera-
tiO/l8, The majority of this equipment is performing sat-
isfactorily; however, the Hllrvey has indicated that it will be
quite difficult to standardize on the effectiveness of manyofthe
control methods. The manufacturing diversity existing
betw~n plants is B problem which must be carefully con-
sidered if uniform stnndaros are to be developed. In spite of
these problems it is believed that the impreBBive evidence of
available handling, conveying, and dust control procedures
IInd ter:hnology whieh have been outlined in the surv"y should
provide It baRia for preparinl/; r;ffective emission standards
(or regulations) for this industry. The lime companies
('xIJCd to develop their own voluntary regulation program and
it is believed that with the continuing cooperation of gevern-
mental officials, the industry can control the environment in
the vicinity of quarries and lime proeeBBing operntions.
The National Lime ABBocil~tion Pure Air Committee iH
eVILiuating all of the available information and is currently
prepl\ring suitable guide lines to assist interested parties in
formulatinjt speeific control procedures that can ue directly
applied to the proouctioll of limm,tone and lime productH.
200
Acknowledgment
The information presented in this report represents the
efforts of a substantial number of contributors who have
indicated their preference for remaining anonymous. The
author, however, wishes to expreBB appreciation to all of them
for their help.
Most of the survey findings were analyzed by Robert
Boynton (Executive Director of the National Lime ABBOcia-
tion) who applied considerable time in evaluating the informa-
tion which he received. In addition, Frank Wi11ard (Regional
Air Pollution Control Engineer of the Pennsylvania Depart-
ment, of Health) Rnd Lax Jain (Environmental Engineer of
the Foote Mineral Company) a member of the National Lime
Association Pure Air Committee, both provided valuable
assist,llI1ee in preparing this report.
Reference.
1. Lewis, C. J. and Crocker, D. D., The Lime Industry's Prob-
lem of Airborne Dust.. TI-2 Report No. 10, J. Air. Poll.
Control A 880C, , 19 (1), :n (Jan. 1969).
2. Pennsylvania Department of Health. Rep;ulation IV-
Guide Lines 1.0 Cont.rol Air Pollution from Sources of Par-
ticnllLte ot' nIL-eous Matter Emissions. Adopted March
1ii,I!lOG.
Appendix I. Rotary Kilns
Sevent.y-two kilns were reported ranl1;ing from 50 to 650
tpd capacity.
Stack heights ranged from 40 to 120 ft in height. One
stack height was reported at 250 ft servicing three large-
co.pacity kilns.
Co.s volumes rartged from 12,400 to 90,000 scfm with a
mean vo.luc of 38,000.
Sto.ck temperatures ranged from 100° to OOO°F.
Fupls uscd-60% pulverized coal, 28% natural gas, 6%
combination of coal and gas, and 6% Bunker C fuel oil.
Bap;house filter areas ranged from 70,000 sq ft and 12
compartment systems to 750 sq ft single compartment systems.
Air to cloth ratios ranged from 2.5: 1 to 1.7: 1 with a mean
ratio of 2.2: 1.
Efficiencies of collection ranged as follows:
1. Cydones-30-03.3% (depending
ondary dust removal)
2. HcrubberIr-03-99.5%
3. Ba!(houses-98-90.8%
Estimate of Rotary Kiln Control Costs.
Capacity -350 tons/day
Exhaust 01\8 Volume -100,000 cfm
Exhaust GA.- Temperature-550°F
Power Cost -$.OI/kwhr
on primary or &eo-
Operating Maintenance
TYCe of cost per cost per
c~)l ector Cost of unit year year
For 99% Efficiency
Daghouse $100,000 114,000 18,000
I'Jlectrostatic
precipitator 200, 000 2,300 2,000
Scrubber 60,000 M,OOO 6,000
"'or 97% Efficiency
Daghouse 1150,000 $14,000 18, 000
Electrostat,ic
precipitat.or 100,000 2,300 2,000
Scrubber 50,000 32,000 6,000
. The estimates are based on purchase of equipment during the
lust fifteen years and do not represent current capital coata, many
of which have increased because of inflation faotors. In addi-
tion, the I\st.imatt1s do not include total installation and start-up
CUAt-A.
Journal of the Air Pollution (.,,, .;;,~I ,\ «!'datlon
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