EPA-600/2-75-074
November 1975
Environmental Protection Technology Series
EVALUATION OF A
PARTICULATE SCRUBBER ON A
COAL-FIRED UTILITY BOILER
Industrial Environmental Research Laboratory
Office of Rese evelopment
U.S. Environmen m Agency
Research Triangle Park, North Carolina 27711
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RESEARCH REPORTING SERIES
Research reports of the Office of Research and Development,
U.S. Environmental Protection Agency, have been grouped into
five series. These five broad categories were established to
facilitate further development and application of environmental
technology. Elimination of traditional grouping was consciously
planned to foster technology transfer and a maximum interface in
related fields. The five series are:
1. Environmental Health Effects Research
2. Environmental Protection Technology
3. Ecological Research
4. Environmental Monitoring
5. Socioeconomic Environmental Studies
This report has been assigned to the ENVIRONMENTAL PROTECTION
TECHNOLOGY series. This series describes research performed
to develop and demonstrate instrumentation, equipment and
methodology to repair or prevent environmental degradation from
point and non-point sources of pollution. This work provides the
new or improved technology required for the control and treatment
of pollution sources to meet environmental quality standards.
EPA REVIEW NOTICE
This report has been reviewed by the U.S. Environmental Protection
Agency, and approved for publication. Approval does not signify that
the contents necessarily reflect the views and policies of the Agency, nor
does mention of trade names or commercial products constitute endorse-
ment or recommendation for use.
This document is available to the public through the National
Technical Information Service, Springfield, Virginia 22161.
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EVALUATION OF A
PARTICULATE SCRUBBER ON A
COAL-FIRED UTILITY BOILER
by
D.S. Ensor and B.S. Jackson, Meteorology Research, Inc.
S. Calvert and C. Lake, Air Pollution Technology, Inc.
D.V. Wallon. R.E. Nilan, andK.S. Campbell, Stearns -Roger, inc.
T.A. Cahill and R. G. Flocchini, University of California--Davis
Meteorology Research, Inc.
464 West Woodbury Road
Altadena, California 91001
Contract No. 68-02-1802
ROAP No. 21ADL-092
Program Element No. 1AB012
EPA Project Officer: Leslie E. Sparks
Industrial Environmental Research Laboratory
Office of Energy. Minerals, and Industry
Research Triangle Park. NC 27711
Prepared for
U.S. ENVIRONMENTAL PROTECTION AGENCY
Office of Research and Development
Washington, DC 20460
November 1975
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CONTENTS
Page
List of Figures v
List of Tables vii
Acknowledgement ix
Glossary of Terras xi
Sections
I Introduction 1
II Conclusions 3
III Performance Tests 7
IV Test Results 35
V Engineering Analysis 75
VI References 79
Appendices
111
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FIGURES
_No. Page
1 Scrubber System g
2 Sketch of Ducts Showing Sampling Ports (Not
to Scale) 10
3 Assembly Drawing of Model 1502 Inertial Cascade
Impactor 14
4 Schematic Diagram of Diffusion Battery System 18
5 University of California, Davis, Aerosol Analysis
System 20
6 Collection Disc with Substrates 22
7 Diagram of the Plant Process Visiometer 26
8 Velocity Traverse Inlet Ducts, 11/18 38
9 Results of Inspection of Scrubber Packing Compart-
ments 39
10 Combined Penetrations for Diffusion Battery and
Cascade Impactor (December 10, 1974) 49
11 Combined Penetrations of Diffusion Battery and
Cascade Impactor (December 11, 1974) 50
12 Combined Penetrations for Diffusion Battery and
Cascade Impactor (December 12, 1974) 51
13 Scrubber Penetrations for Selected Elements 56
14 Scattering Coefficient as a Function of Mass
Concentration 64
15 Scattering Coefficient Measured Upstream and
Downstream. 65
16 Effect of Particle Size Distribution on Particle
Volume/b [Ensor and Pilat, 1971] 68
S CcLt
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FIGURES (continued)
No,
17 Microphotograph of Stage G Particle Deposit
Outlet Sample (dB 0 = 0. 37 //m) 72
18 Microphotograph of Filter 73
VI
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TABLES
No. Page
1 Nominal Cut Diameters for Impactor Tests 15
2 Cumulative Loss Fraction in Flow Piping (Percent) 33
3 Ratio of Daily Mass Concentration in Each Duct to
the Average Mass Concentration 37
4 Scrubber Collection Efficiency 41
5 Data Pairs Used in Penetrations 43
6 CNC Data for Diffusion Battery Tests 44
7 Comparison of Count-Basis Versus Gravimetric-
Basis Total Mass Loading 46
8 Ratio of Elemental Concentrations Relative to Si
for Six Inlet Tests 53
9 Ratio of Elemental Concentrations Relative to Si
for Ten Outlet Tests 54
10 Penetration of the Elements Through the Scrubber
for December 10, 1974 57
11 Particle Penetration Summary 58
12 Comparison of Mobile Bed Studies 59
13 Plant Process Visiometer and Inertial Impactor Data 63
14 Correlation of Mass Concentration with Scattering
Coefficient 66
15 Test Conditions 70
vu
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ACKNOWLEDGEMENT
The technical coordination and assistance of Dr. Leslie E. Sparks,
Environmental Protection Agency project officer is greatly
appreciated. The efforts of Public Service Company of Colorado
personnel in providing assistance during the source test and the
engineering evaluation were vital to the success of the project.
IX
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GLOSSARY OF TERMS
A = coefficient of regression equation
A = calibration constant
z
B = coefficient of regression equation
b «. = extinction coefficient, m"1
bscat = extinction coefficient due to scattered light, m
-i
d c = particle diameter with 50 percent penetration through
scrubber, micron
dpi = particle diameter of size i, micron
dg0 = particle diameter with 50 percent collection efficiency, micron
E = fractional efficiency
L = stack diameter, m
LF = loss fraction due to laminar diffusion and sedimentation
B
LF = cumulative loss fraction
LF = loss fraction due to impaction at bend
LF = loss fraction due to turbulent deposition
Mp = mass of particles in the infinitesimal size range
(dp + ddp), g
M~ = cumulative mass concentration of particles smaller than
"dpi", g/cm3
Na - number of characteristic X rays of element Z
Np = cumulative number concentration of particles smaller
than "dp", no. /cm3
Npt = total number concentration of particles, no. /cm
xi
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Pt = penetration of aerosol through scrubber
Pt^ = penetration for each size fraction
Q = total charge
TC = correlation coefficient for fit to log normal size distribution
Wj. = total particle mass, mg
Z = atomic number
AP = pressure drop, cm H3O
0(0) = volume scattering function, m2/m3
o
(pt)z = area density, ng/cm
Op = geometric standard deviation
8 = scattering angle, radian
xn
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SECTION I
INTRODUCTION
OBJECTIVE
The objective of this study was to test and evaluate a full-scale
scrubber system, used to control fly ash emissions from a coal-fired
utility boiler. The scrubber was not to be "tuned" for best perfor-
mance, but simply to be operated in the normal manner.
The primary objective of the field study was to determine the
efficiency of the scrubber as a function of particle size. The plant
operating parameters, plume opacity, and chemical composition of
the emissions were also measured to interpret the efficiency data.
The engineering evaluation was a complete study of the economics
and operating history of the scrubber. The scrubber system was to
be typical of the industry, with sufficient operating experience for a
basis of evaluation.
SCOPE
The subject scrubber was a Turbulent Contact Absorber (TCA),
manufactured by Universal Oil Products (UOP), installed on the
Cherokee #3 Boiler, owned and operated by the Public Service
Company of Colorado in Denver.
The field work extended over two test periods : November 3,
to November 23, 1974, and December 9 to December 13, 1974. The
first sampling period was terminated because of plant problems. The
Meteorology Research, Inc., (MRI) team was responsible for the cas-
cade impactors, opacity, and plant data, -while the Air Pollution Tech-
nology, Inc. , (APT) team was responsible for the operation of a diffu-
sion battery.
The engineering analysis, conducted by Stearns-Roger, Inc., considered
information from startup in October 1972 to November 1974.
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SECTION II
CONCLUSIONS
The conclusions from this study are:
I. The scrubber was nominally operating at the design particulate
removal efficiency of 95 percent of the mass of particulate matter
entering the scrubber.
2. The penetration of submicron particles was much greater than
that measured in previous studies of TCA scrubbers [Calvert
et al, 1974]. Based on the present observations of random
variation in efficiency at constant pressure drop, the inconsis-
tent behavior of the three sections of the scrubber and the dif-
ferences in the chemical composition of inlet and outlet aerosol,
entrainment of mist appears to significantly influence the con-
centration of submicron aerosol at the outlet of the scrubber
system. The dominent and poorly defined influence of mist
entrainment observed in this scrubber may be unique for this
particular scrubber during the particular time period of the
test. Thus, the application of the data to developing general
mobile bed scrubber models is not feasible.
3. The mass penetration as a function of particle diameter was
a strong function of the elemental composition of the particles.
The insoluble materials, such as Al and Si (presumed to be in
an insoluble oxide form), have a much lower penetration than
the total penetration based on mass, whereas the soluble ele-
ments such as Cu and Zn, have larger penetrations. The im-
plication is that much of the submicron emission -was due to en-
trainment of droplets. There was also an apparent generation
of sulfur particulate matter in the scrubber.
4. The origin of the entrained mist may have been the scrubbing
beds. The superficial gas velocity through the scrubber beds
was calculated to be 4.5 m/sec. The recommended superfi-
cial gas velocity is 2. 8 m/sec _+ 20 percent. Superficial gas
velocities greater than 3 m/sec forces the contactors to the
top of the compartments with an increased pressure drop and
scrubber liquid entrainment.
The superficial gas velocity through the chevron type entrain-
ment separators of 3. 3 m/sec was within the recommended
operating velocities. Thus, a heavy entrainment of mist from
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the scrubber bed followed by a normally operating mist
eliminator may have produced the observed variable con-
centration of submicron particles.
5. The opacity was measured at both the inlet and outlet of
the scrubber with a Plant Process Visiometer. The
scattering coefficient was correlated with mass (the cor-
relation coefficient is 0. 8) and the results were explained
by Mie light scattering equations.
6. The installed cost of the scrubber was $4,400, 000 or
$29/kw (1972 dollars).
7. The annual operating costs in the year prior to November
1974 were approximately $495, 000/year. Based on 75 per-
cent availability, the cost was 0.5 mills/kwh.
8. The major maintenance problems are:
• breakage of mobile bed contactors
• plugging and corrosion of the air reheaters
• operational problems with the quillotine dampers
• migration of mobile bed contactors
• failure of the recirculation pumps
• failure of the rubber linings in the piping
• buildup of solids in the presaturator
• problems with mist eliminators
• problems with stack damper interlock system
• failure of recirculation system venturi flowmeters
• problem with booster fan bearings
• weather related problems such as freezing of
process lines.
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9. An analysis of scrubber reliability indicated that after a
dramatic decline in availability of the unit after installa-
tion, the availability has been increasing with time. This
has been attributed to the efforts of the Public Service
Company of Colorado in providing maintenance and solu-
tions to many of the persistent problems.
10. In a feasibility analysis of producing a "problem-free"
scrubber system (no equipment is ever truly problem-
free), it was found that many improvements have been
devised since installation of the scrubber. These in-
clude an indirect flue gas reheater, an enclosure for
the scrubber, and the use of improved components such
as newer design recirculation pumps. Improvements
•which require more development are better mobile con-
tactors and more reliable flue gas isolation gates.
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SECTION III
PERFORMANCE TESTS
DESCRIPTION OF SYSTEM
Power Plant
The Cherokee Power Plant is located in north Denver, Colorado,
near the South Platte River. The #3 unit has a nameplate rating of
150 mw. The Babcock and WIlcox Radiant Boiler (installed in 1961)
has a steam capacity of 0. 52 X 106 Kg/hr(1.14 X 106 lb/hr)ata
design pressure of 1.48 X 10 Pa (2150 psi) and a steam tempera-
ture of 554. 1°C (1,000.5°F). The gas cleaning equipment consists
of mechanical collectors, an electrostatic precipitator, and a wet
scrubber arranged in series.
The unit normally burns coal or natural gas. The coal is mined in
western Colorado and has a sulfur content of about 0. 5 percent, ash
content of 9 percent, and a heating value of 2.492 X 10 J/Kg
(10, 712 BTU per pound).
Scrubber
The Model 6700 Turbulent Contact Absorber Scrubber, designed by
UOP, Air Correction Division, was installed in 1972 to supplement
control of particulate matter by the electrostatic precipitator and
mechanical collectors. A diagram of the system is shown in Figure
1. The flue gas from the precipitator passes into two parallel in-
duced draft fans. A bypass damper is used to direct the flue gas
either into the stack or into the scrubber. The flue gas (under design
conditions), 17, 000 AM3 /min, at 137 °C (610, 000 ACFM at 280 °F),
enters the booster fans to offset the pressure drop through the scrub-
ber. In the presaturator, 1440 4/min (380 GPM) of makeup water is
sprayed into the gas to reduce the temperature to approximately 52 °C
(125°F). From the presaturator, the gas enters the scrubber. The
scrubber consists of three stages of fluidized beds packed with 3.8
cm (1.5 in. ) diameter plastic balls arranged into three seperated
parallel scrubber sections. The two outer sections each handle 20
percent of the flow, while the center section handles the remaining
60 percent. All three sections can operate independently to pro-
vide flexibility of operation.
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00
Flue Gal
From
MuJtileif
Control
Dampera
/
Downstream
Sample Point
S Parallel Ducts
Stack
Mechanical
Collector Upstream
Sample Point
, 4 Parallel Duels
Mi>t
Eliminator
Wash
I.olition
Damper.
\ I ' ' I s~ Reh*»l Stc»n
\-r-VWWf
Mitt Kliminatori
Block /Hypaai
j/ Damper
itatic
Precipitator
Scrubber
/^, \^^ Pumpi
Recirculation
(5)
Slurry Drawoff
Figure 1. Scrubber system
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The scrubber liquor, 113, 700 4/min (30, 000 GPM) is pumped with
five pumps from the bottom of the scrubber to a header equipped
with spray nozzles at the top of the packing. Under normal operation,
853 J&/min (225 GPM) of slurry is purged from the system to prevent
buildup of solids in the recirculated liquor. The slurry from the
scrubber is pumped to an ash pond for disposal.
The scrubbed gas passes through a chevron-type mist eliminator
made of fiberglass reinforced plastic where entrained droplets are
removed. The mist eliminators are sprayed once a shift from the
top to prevent accumulation of solids.
The gas is then heated by steam coils to 85°C (185°F) before entering
the stack to prevent corrosion of the stack and duct work and to provide
plume buoyancy after discharge into the atmosphere. The steam coils
are equipped with two sets of soot blowers to remove fly ash from the
heat transfer surfaces.
The scrubber was designed to the following specifications [Raban, 1974]:
Gas Flow 1,036,000 AM3 /hr, 610,000 ACFM
138°C (280°F)
Liquid to Gas Ratio 7.4 JL/m3 (55 gal/1000 ft3)
A P 30. 5 cm H2O (12 in. HSO)
Inlet Concentration 0.92 gm/m3 (0.40 grains/SCF)
Outlet Concentration 0.046 gm/m3 (0.02 grains/SCF)
Efficiency of Removal 95 percent
Test Points
The scrubber inlet test points were located at the outlet of the
electrostatic precipitator and at the inlet of the induced draft fan.
The sample ports were about 4 m above grade. The ducts were
about 30° from vertical and the cross sections are shown in Figure 2.
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North
i
-
336. 6 cm
i
-
-
16
17
18
19
20
11
12
13
14
15
- -
•* -•
- -
. _
6
7
8
9
10
1
2
3
4
5
110.3 J
IV III II i
Ports
"Five 3-in.
pipe couplings
Inlet Ducts
Top
Outlet ports, 3 each side, 8 center, 10 cm ID, 62. 9 cm-64. 8 cm deep
i I I
J
227. 3 <
1
rm
I
i
1 2 3
151.4
rtf i i ^
^ cm ~
A
12345678
* ,„ ilT rf *} i-n-i •-
B
1 2 3
152.4
•* ' cm ^'
C
Outlet Ducts
Figure 2. Sketch of ducts showing sampling ports (not to scale)
10
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The scrubber outlet ports were downstream of the air reheater.
The ports in the top of the horizontal duct were accessible from
a catwalk across the top of the scrubber. Immediately downstream
of the sample point are multileaf control dampers.
TEST PROGRAM
Test Parameters
The tests were assigned primary and secondary priorities. The
primary tests formed the major substance of the study. The
secondary tests were scheduled around the primary tests.
1. Primary Tests
Impactors for Mass Distribution
The use of cascade impactors for mass size distribution
from 0. 3 to 20 Mm formed the bulk of the data.
Diffusion Battery
The diffusion battery tests were essential to measure the
size distribution less than 0. 3 £lm in diameter.
Plant Process Visiometer
Two Plant Process Visiometers (PPV) were installed in
the duct work at the sample points. The instrument was
used to provide a real time output of opacity to detect up-
sets in the boiler, precipitator, or scrubber.
2. Secondary Tests
EPA Method 5
The EPA Method 5 tests for total mass were assigned a
low priority. One test •was conducted.
11
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Impactor Test for Count
The impactors were operated for short times to obtain
light deposits. The deposits -were examined with optical
and electron microscopes at MRI. Mylar substrates and
silver membrane filters were used.
Impactor Tests for Elemental Analysis
The tests for elemental analysis had similar test procedures
as the normal mass size distribution sampling. The major
differences were the use of a Mylar collection surface and a
Whatman 41 backup filter.
Test Strategy
This included 3 phases:
• Phase 1 - Evaluation of the distribution of aerosol mass
concentration at the inlet. With the limited resources in
manpower and equipment, the evaluation of the source
was attacked one aspect at a time. All four inlet ducts
were sampled at the same time. The cascade impactor
trains were supplemented with in-stack filter probes to
establish the consistency of the concentration.
• Phase 2 - Evaluation of outlet distribution of aerosol mass
concentration. Similar parallel tests were used on the out-
let of the scrubber to indicate the variation in the ducts.
• Phase 3 - Simultaneous inlet-outlet tests for scrubber
efficiency. The final phase of the field program -was
the simultaneous inlet-outlet tests with both primary
and secondary tests.
12
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TEST METHODS
Cascade Impactor
The impactor used in this study was designed at Meteorology Re-
search, Inc. , to facilitate sampling of particulate matter in stacks.
A drawing of the sampler is shown in Figure 3. The design is based
on a simple annular arrangements of jets and collectors reported by
Cohen and Montan [196?]. The simple jet-collection plate geometry
has been thoroughly studied by many investigators [ for example,
Marple and Liu, 1947]. The use of a collection disc allows flexi-
bility in choice of substrates. For example, either a greased sur-
face or a filter mat can be used to enhance particle collection. Al-
so, inert materials can be used for special sampling conditions.
The assembly has been constructed using quick disconnect rings to
increase the flexibility of application. "O" rings are used under di-
rect compression for a positive gas seal of the plates containing the
jets. The nominal cut diameters are shown in Table 1.
Particle Collection Substrates
The performance of a cascade impactor is strongly dependent on
the surface -where the particles are collected. The two most popu-
lar substrates have been glass fiber filter mats and greased sur-
faces. A greased surface was used in preference to the filter mat
because recent data reported by Smith et al [1975] indicate that
glass fiber filter mats react with stack gases. Also, Rao [1975]
reported that filter mats have poor collection efficiency. (These
studies were in preliminary form at the beginning of this project. )
In preparation for the field work, a number of materials were
screened as coatings to enhance particle collection. Apiezon L
high-vacuum grease composed of high-molecular weight hydro-
carbon had the best properties of the materials tested in terms
of stability and particle adhesion. Thus it was selected for use
in these tests.
Collection Substrates -
The collection discs were prepared by cleaning them, in acetone
and coating the upper area with a solution of Apiezon L, high-
vacuum grease in benzene. The collection discs were heated
for 3 to 4 hours at 171°C (340°F) to drive off volatiles. After
heating, the plates were allowed to cool in a des sic cation chamber
13
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Nozzle
Jet Plate
Collection
Disc
1st Stage
"O" Ring
Filter
75- II3
Figure 3. Assembly drawing of Model 1502 Inertial Cascade Impactor
14
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Table 1. NOMINAL CUT DIAMETERS FOR IMPACTOR TESTS
Stage
A
B
C
D
E
F
G
Filter
Particle Size at 50 Percent Efficiency
(microns)
30
15
6.0
2.4
1.5
0.65
0. 37
Less than 0. 37
Flow rate 14
15
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for 24 hours. The discs were then weighed on a Cahn 4100 ana-
lytical balance to 0.01 mg. The weights of the discs were approx-
imately 2100 mg. Counterweights were used to improve the sensi-
tivity of the weighing. The discs were stored in labeled 15 x 60 mm
petri dishes.
Test Procedures -
The impactors were assembled with the collection discs and a Gel-
man Type A final filter. Care was taken to avoid contamination.
The test was conducted as described by Pilat et al [1970]. The
test train was a commercial EPA Method 5 (Joy Manufacturing Co. )
modified to use an in-stack impactor. The probe and out-of-stack
filter were replaced by the in-stack impactor, a stainless steel
probe with a long radius bend near the impactor, and a vacuum
hose connected to the first impinger.
A velocity traverse was taken with a Type S pitot tube as described
by EPA Method 2 just before the impactor tests. The impactor
sample was taken at one point in the duct without traversing. Care
was taken to select an inlet nozzle and sample rate to allow isokinetic
sampling.
The sample times were carefully selected to avoid overloading of
the collection discs. The maximum weight per disc is about 10
mg to avoid particle losses from the stage as reported by Bird
et al [1973].
The tests downstream of the scrubber were conducted with heated
impactors. A rubber coated heating jacket, made by Electrofilm,
Inc., with a temperature sensor, was slipped over the impactor
and connected to the oven temperature controller of the Method 5
train. A temperature 17 °C (30 °F) above the duct temperature
was selected for most tests.
After the test, the impactor was removed from the duct, detached
from the probe, and allowed to cool. In a trailer, the sampler was
carefully disassembled. The collection discs were placed into
60 X 15 mm petri dishes for protection and storage. The material
lost to the walls of the impactor was brushed onto the appropriate
substrate surface. The samples were desiccated and then weighed
again on the Cahn 4100 balance. The petri dishes were sealed with
tape.
16
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Diffusion Battery
Description -
Inertial impaction devices (cascade impactors) are normally in-
sufficient for measurement of particulates less than 0.3 Jim (actual
diameter). Fractionation of these particles is best accomplished
by diffusional collection devices, or diffusion batteries, usually con-
sisting of closely spaced parallel plates or long, thin tubes. Large
quantites of pumps, dilution apparatus, and other battery related
equipment are bulky and prove to be cumbersome in field use. For
this and other reasons, Air Pollution Technology, Inc. developed a
portable screen diffusion battery which is lighter and more mobile
than previous devices.
The Portable Screen Diffusion Battery utilizes a series of layered
screens intermittently separated for sampling purposes (Figure 4).
Size fractionation by the diffusion battery is detected by measure-
ment of overall particle concentrations of the gas stream into and
out of a known number of screens using a condensation nuclei
counter (CNC). Concentrated aerosol samples are diluted until
compatible with the CNC (~104 particles/cm3 ). Screen penetra-
tion data are then analyzed to determine size distribution and cum-
ulative mass loading of the particulates in the stream. If desired,
cascade impactor and diffusion battery analyses can be combined
and an overall characterization of the particulate size distribution
(and scrubber penetration) obtained.
Test Procedures -
A minimum of two diffusion battery sample runs was taken per day;
one inlet and one outlet. Each run consisted of a continuous series
of CNC readings from the sample ports over a period of approxi-
mately 60 minutes. Normally, CNC counts were taken at each dif-
fusion battery sampling point in order of increasing number of
screens and then the process was repeated until three to four sets
of readings were obtained. Continuous monitoring of flows, tem-
peratures, and pressures enabled steady operation of the diffusion
battery. Conditions in the duct (pressure, gas velocity, tempera-
ture, and water vapor content) were obtained during the impactor
tests.
The size of particles entering the diffusion battery was limited
using a cascade impactor precutter on the in-stack end of the probe.
Isokinetic sampling was not maintained because the particles to be
17
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STACK
GAS
00
CASCADE
IMPACTOR
1st DILUTION
FLASK WITH CHARGE
NEUTRALIZERS
1
VACUUM
PUMP
1
ROTAMETERS
J
JL
FILTER
m
ROTAMETER
FILTER
DIFFUSION
BATTERY
DESSICANT
FLOW
METER
2nd
DILUTION
FLASK
TO
C.N.C
PUMP
>. VACUUM
PUMP
Figure 4. Schematic diagram of diffusion battery system
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measured were too small to be segregated by inertial effects from
bends in the gas streams. The sample stream entering the diffusion
battery was immediately diluted with heated, dried, filtered air to
control condensation. Two Polonium 210 charge neutralizers were
inserted into the flask to eliminate electrostatic effects.
A portion of the resultant aerosol was directed through the diffusion
battery and the outlet diluted to a concentration measurable by the
Gardner CNC. The aerosol from the second dilution flask was
sampled with the Gardner CNC. The excess aerosol was exhausted
through the vacuum pump. The excess aerosol from the first dilu-
tion was passed through an absolute filter and pumped to the atmo-
sphere. The Gardner CNC was calibrated daily against a standard
B. G.I. Pollak, Model P, CNC and found to read consistently 33 per-
cent lower than the Pollak CNC for the concentration range used in
the testing.
Elemental Analysis
Ion-Excited X-Ray Analysis Method (IXA.) -
The elemental analyses of the samples were accomplished with ion-
excited X-ray analysis (IXA) at the Crocker Nuclear Laboratory,
University of California, Davis. This system described by Floc-
chini et al [1974] permits analysis sensitivity over a wide range of
elements. The method has been primarily used for atmospheric
aerosol and water trace analysis. One of the efforts in this study
was to extend the capability to stack measurements.
The basic sensing system is shown in Figure 5. An 18 MeV alpha
beam from the cyclotron passed through remotely readable graphite
collimators and impinged on the thin target which was mounted at an
angle of 45° to the incoming beam. The sample or target is mounted
into a 35 mm slide. The target slide changer was operated under
real time computer control. Beam spot uniformity was achieved
by the use of a diffusion foil (6. 4 JUm Al) and different sized target
collimators. The beam was then collected by a Faraday cup and
integrated to a precision of about 2 percent to give the total charge,
Q, that passed through each sample. X-rays that passed through
an active filter and a 25 micron Be window were converted into
electrical pulses by a 10 mm X 3 mm liquid nitrogen-cooled Si (Li)
detector and associated pulsed optical feedback circuitry. Data were
accumulated in a Digital Equipment Corp. PDP-15/40 computer with
Nuclear Data 2200 Analog-to-Digital Converter's integral to the sys-
tem, giving a spectrum of characteristic X-rays and a smooth back-
ground.
19
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TO CONTROL ROOM
DIFFUSION
VACUUM
PUMP
CYCLOTRON
BEAM
SWEEPING
MAGNET
PULSE
SHAPING
ELECTRONICS
TO SWEEPER
• TO POP-15
75-112
Figures. University of California, Davis, Aerosol Analysis System
-------
The number of characteristic X-rays, Nz , corresponding to some
transition of element Z were correlated with the area density (pt)
of the element present in the sample by z
N = A (pt) Q (1)
z z z
where Az is a constant determined with the use of elemental stand-
ards. Once Az was known, NZ could be extracted from, each spec-
trum quickly, accurately, and automatically, since analysis time
was routinely less than two minutes per sample.
Substrates for Elemental Analysis -
The impactor jet design -was found to be quite suitable for Ion-Excited
X-Ray Analysis (IXA). The area of the ion beam is about 1 cm3 or
about 1/12 of the cross sectional inside area of the impactor. The
holes are in multiples of 2, allowing an even number of deposits to
be analyzed by the beam. An exception is the first stage where one
deposit is analyzed. The first stage deposits have an area of 0.6
cm each and can be easily covered by the beam. A jet too large
would have a deposit of particulate matter larger than the beam and
would result in a poor analysis.
A substrate was needed with a much lower density and atomic num-
ber than the particle deposit. The X-rays scattered from, or created
by, a dense background would mask the spectra from the sample . The
collection surface should have a low background of heavy metals to re-
duce the problems of background substraction. Also, it is not desir-
able to transfer the particle deposit to another surface because of
contamination and loss of sample.
These problems -were eliminated with the development of a new sub-
strate-collection disc system. The collection disc with a substrate,
shown in Figure 6, is a basic component of the impactor. The disc
is a self-supporting aluminum stamping designed for low tare weight
(2000 mg) and low cost» It is intended to be used only once for a
permanent record of the test and to prevent the likelihood of contam-
ination of the sample from previous tests. The collection substrate
was a 92-gage Type S Mylar washer coated on both sides with grease
(Apiezon L) to hold it in place and present a tacky surface for particle
collection. The Mylar washer with the sample is peeled from the
metal stamping and mounted in a 35 mm slide holder for analysis.
21
-------
92-GAGETYPE S MYLAR
COATED TOP AND BOTTOM
WITH GREASE
ALUMINUM
COLLECTION
DISC
75 -114
Figure 6. Collection disc with substrates
22
-------
Thus, both the requirements of a rigid mount for handling and a thin
substrate for analysis were accomplished.
Washers of 92-gage Type S Mylar were punched to loosely fit into
the collection disc. The washers were thoroughly washed in ace-
tone and then ethanol to remove any contamination. The washers
were then dipped into a dilute solution of Apiezon L high-vacuum
grease dissolved in benzene. The excess solvent was allowed to
drain, then the washer was placed into the collection disc and
pressed flat with a rod.
The discs were then heated for 3-4 hours at 171 °C (340 °F) to drive
off volatile material. The discs were then placed in a desiccation
chamber for 24 hours and then weighed on a Cahn 4100 analytical
balance to 0. 01 nag. Improperly prepared substrates would often
pull from the metal backing during heating. These were discarded
and the concentration of grease in benzene increased. Care was
taken not to overload the surfaces with grease. Whatman 41 filter
paper -was used in the backup filter because of its low trace contami-
nation [Dams et al , 1972]. The Apiezon L high-vacuum grease was
tested before the test for trace metals and none were detected. The
Mylar was tested in a similar manner.
Blanks of both the Whatman 41 filter paper and a prepared collec-
tion disc were saved for every impactor test. In addition, only the
filters from the same box and grease from the same tube were used
during the test to avoid any problems which might have been intro-
duced by the quality control of the manufacturer.
The source tests for the elemental analysis were conducted in a
manner similar to that for mass size distribution. After the test,
the desiccated samples -were reweighed on the Cahn balance to ob-
tain the mass collected.
The samples for elemental analysis were hand-carried to the
Crocker Laboratory, Davis, California. At the Crocker Labora-
tory, the Mylar -washer containing the sample was peeled from the
disc and a section 1/2 of the total was sliced from the washer and
mounted in a 35 mm slide plastic holder. The sample was then
analyzed in the normal manner for 29 elements.
Data Analysis
The basic analysis data were in the form of nanograms-per centi-
meter for elements sodium and heavier. These data were printed
23
-------
out and stored on magnetic tape. The impactor flow rates, particle
size cut points (d5o ), and mass loadings were then used to convert
the data to nanograms per cubic meter of gas and to make the neces-
sary corrections. The ion beam analyzed only one impinged spot for
Stages A, B, and G, while two spots were covered for the rest. Thus,
since there are 8 holes in Stage A, 12 in B, 24 in C through F, and 12
in G, the total sampled volume in cubic feet was divided by 12 except
for Stage A, which it was divided by 8. Since the ion beam area was
2
known to be 1.1 cm , a factor could now be calculated for each run
O 3 -*a o
to form the product, (X ng/cm ) (Y cm /m ) = XY ng/m , the
desired end product. The filter conversion factors were obtained by
dividing the total active area by the total flow.
The particle size cut points for each stage (dso) was used to make cor-
If-absorbtion of X-rays. The
in Appendix C.
rections for self-absorbtion of X-rays. The stage d 's are reported
The stage d O's generally varied little from run to run (i.e. , the Stage
A d point was 29. 0 ± 3. 6 ;im for all runs). With knowledge of the
particle diameterand approximate chemical composition, particle size
effects were calculated for each stage [see Harrison and Eldred, 1973,
for details and references]. These techniques had previously been
used in the 1974 international interlaboratory comparison [Camp et
al, 1974] and proved able to accurately handle corrections for up to
a 30 Jim ground rock sample for elements Al and heavier. a In fact,
this was precisely the correction factor used for Stage A. The other
stage corrections were also derived from this formula.
Stage A B C D E -» G Filter
Al 2.6 1.7 1.4 1.16 1 2.2
Si 2.3 1.5 1.3 1.12 1 1.8
S 1.9 1.26 1.17 1.07 1 1.4
Cl 1.8 1.20 1.12 1.05 1 1.26
K 1.5 1.12 1.07 1.03 1 1.14
Ca 1.4 1.09 1.05 1.02 1 1.10
Ti 1.3 1.07 1.03 1.02 1 1.06
V 1.25 111 1 1.05
Cr 1.2 1 1 1 i 1.04
Mn 1.15 1 1 1 1 1.03
Fe 1.1 1 1 1 1 1.02
Other 1111 11
aNa and Mg were seen on may samples, but error and uncertainties
associated with correction effects did not allow quantitative values
to be calculated in most cases.
24
-------
Corrections for layering were not applied, as the light loadings of the
samples and the non-uniform distribution of the deposits made such
corrections highly uncertain but, fortunately, small. Only for Al and Si
on Stages E, F, and G for the downstream samples were the corrections
larger than the particle size corrections, with a value of about 10 percent.
The filter correction, due to absorbtion of X-rays in the filter matrix,
was very difficult to establish. Little previous work is available on
penetration of fine aerosols from stack samples into Whatman 41
filter material. One sample, taken from a stack, was included in the
1974 interlaboratory comparison, however. Since this sample included
sulfur, which was present only in fine particles in this present study,
we assumed that the sulfur value for Whatman 41 should also be corrected
by the factor of 1.4 that gave the correct result for the test sample.
This value amounts to about twice the correction reported by Dzubay
and Nelson [1974] for Gelman GA-1 filter, a filter about one-half as
thick as Whatman 41. All other elements were then also scaled at
similar scaling factors.
It should be stated that, despite previous successes in use of particle
size correction codes, serious uncertainties due to composition and
morphology exist, and no correction should be believed to be better
than ±30 percent. The data, corrected for all above considerations,
was then tabulated and provided in a printed format that minimized space
and provided easy comparison of run to run, stage to stage, by element.
Plant Process Visiometer
Description -
The Plant Process Visiometer (PPV) is a light scattering instrument
developed at Meteorology Research, Inc. , for real-time monitoring of
stack opacity. A diagram of the instrument is shown in Figure 7. The
aerosol was removed from the stack with a stainless steel probe and
was transported into the measurement chamber. The aerosol particles
in the chamber were illuminated by a flash lamp with an opal glass fil-
ter. The scattered light was detected by a photomultiplier tube at
approximately right angles to the flash lamp. The optics have been
designed so that the output of the photomultiplier tube is proportional
to the extinction coefficient due to scattered light. The instrument is
a physical analog of the following equation:
25
-------
Sample Flow
P 1 \
r \ Photc Mui:•&> e;
/ Coliimaior
Electronics
Figure 7. Diagram of the Plant Process Visiometer
26
-------
p
bscat = 2Tr J0 0(e> sinSdG (2)
where
'-'scat = ^e scattering coefficient due to
scattered light
|8( 6 ) = volume scattering function
6 = scattering angle
If there is no light absorption, the scattering coefficient is identical to
the extinction coefficient. The extinction coefficient is related to plume
opacity with the Bouguer Law.
Opacity (percent) = (1 - exp(-bext Ln
100 (3)
where
b , = extinction coefficient, m"1
ext
L = stack diameter, m
The instrument -was spanned with an internal calibrator consisting of
an opal glass lens of known scattering coefficient. The lens was
mechanically placed in the view of the detector for calibration and was
retracted into a sealed chamber between calibrations, the PPV cali-
brator was calibrated with oil smoke with reference instruments
using both an Integrating Nephelometer and a transmissometer. The
PPV was described in detail by Ensor et al [1974].
Installation -
The Plant Process Visiometer at the inlet of the scrubber was LastaJJed
upright at port number 12. The 1. 3 cm ID probe extended 60 cm into
the duct with the nozzle aligned with th.e flow. The sample rate -was
230 liters pei minute. A high-efficiency aspirator at the exhaust of the
optical chamber was? supplied with compressed air from a. Rotron blower.
The exhaust from the aspirator was returned to the stack through an
adjacent port.
The unit at Uie outlet of the scurbber was placed on the walk-way above
the test ports. The 152 cm stainless steel probe was placed vertically
down into the duct in from section B of the scrubber. The probe was
clad with extra electric strip heaters to increase the temperature of
the stack gas to approximately 100 ° C. The gas from the high-efficiency
aspirator was exhausted to the atmosphere.
27
-------
In both instruments, the probe and upper cone of the optical chamber
were electrically heated. The stack, probe, and optical chamber con-
tained temperature sensors. A remote control panel was rack-mounted
in the work trailer. The light scattering coefficients were recorded on
strip charts, and the temperatures were displayed with a panel meter
and multipoint switch. The remote control panel had controls to allow
remote operation of the instruments. The outlet instrument was equipped
with an automatic zero and span system functioning on a two-hour cycle.
Test Procedures -
The Plant Process Visiometers were adjusted to provide a mid-scale
reading. The full-scale reading of the inlet and outlet Plant Process
Visiometers were 0.06 and 0.45 m"1, respectively.
The internal opal glass calibrator was used as a field reference. After
installation, the instruments were operated continuously. The zero
and span was checked at least three times per day by back-flushing
with clean air and activating the calibrator. Thus both a check of the
electronics and drift and contamination of the optical surfaces was
obtained. When required, the units were cleaned and adjusted.
ERROR ANALYSIS
An error analysis was conducted to aid in procedure development and
interpretation of the results.
Cascade Impactors
Cascade impactors were used as the principal means of obtaining infor-
mation about the inlet-outlet size distributions. It was important to
understand the sources of error and how the error can be minimized.
The procedural errors include the accuracy of the weighing of the
deposits, reading of the test data such as temperature, gas volume,
time, and pressures. The errors from the impactor design and con-
struction include wall losses, accuracy and precision in construction
of critical components, and particle reentrainment from the collection
surface.
Some of the design and construction limitations can be reduced by pro-
cedures such as recovering the wall losses and by sampling at certain
flow rates and times to reduce reentrainment errors and by calibration
of the impactor. The experimental data obtained with commercial
impactors was reported by Smith et al [1974].
28
-------
Smith et al [1974] reported that all impactors tested had appreciable
wall losses for particle diameters above ten microns. This error can be
reduced by brushing the material from the wall onto appropriate collec-
tion discs. The flow velocity through the impactor jets should not be
above 65 m/sec to be absolutely certain of avoiding reentrainment of
particles from the collection substrate. The extent of reentrainment
will depend on the properties of the material and the amount of deposit.
Lundgren [1967] reported that reentrainment increased as the collection
surface became coated with particles. However, Rao [1975] reported
that collection efficiency increased with increased particle load. When
the particle weight is over 10 mg, part of the deposit may break away
from the surface and migrate "within the impactor. The light-weight
deposit places importance on accurate weighing. The analysis of impactor
errors was limited to the weighing error and in the calculation of collec-
tion efficiency error. The effects of weighing errors on the results of
impactor tests have been analyzed by Sparks [1971]. An analysis of the
•weighing error using three different estimations •was reported by Fegley
et al [1975]. The results indicate that, when the weight of sample per
stage is less than 1 mg when weighed with a balance with a precision of
0.05 mg, the error in the fractional mass will be greater than ten percent.
The error in the particle diameter was analyzed by the use of the Ranz
and Wong [1952] solutions describing the impaction of particles from a
round jet impinging on an infinite flat plate. The results reported by
Fegley et al [1975] indicated that the tolerance of machining the jet
holes is weighted nine times the other errors in determining particle
diameter. Measured hole diameters for each impactor stage were used
in the reduction of the data to minimize the effect of the hole tolerance
on the calculated stage dso- The error in the d50 will be less than
five percent.
Diffusion Battery
The Screen Diffusion Battery was calibrated in Air Pollution Technology's
(APT) small particle laboratory. An aerosol of known size distribution
was generated and passed through the diffusion battery. The total num-
ber concentration was measured with a condensation nuclei counter at
the battery inlet and at several locations along the battery corresponding
to different solidity factors. Screen solidity factor is a semi-empirical
quantity which is obtained by laboratory calibration and depends upon the
cumulative number of screens. The penetration of particles (percent)
was then calculated and plotted against solidity factors on semi-logarithmic
paper. The experiment was repeated with the same aerosol until a smoothed
average curve relating number penetration to solidity factor was obtained.
From the smoothed curve, a correction factor for the theoretical diffusion
battery performance was determined.
29
-------
The scatter of data points about the smoothed (fitted) calibration curve
represents the experimental error in the penetration measurement.
This measurement error included meter reading error, accuracy of the
CNC, etc. The measurement error was defined in terms of relative error,
or the deviation from the averaged penetration value divided by the
averaged value.
This procedure was repeated on other aerosols of known size distribu-
tion. The maximum relative error was then determined from these
experiments for each solidity factor. The maximum relative error
the the Screen Diffusion Battery determined by this method is 10.4 per-
cent for solidity factors of 13, 26, and 40.
Elemental Analysis
The ion-induced X-ray analysis is subject to two sources of uncertainties:
system errors and sample effects.
The system uncertainties include:
1. Statistical uncertainty in peak counts
2. Uncertainty in gravimetric standard
3. Integration of ion beam
4. Ion beam attenuation
5. Electronic correlations
6. Peak integration and background uncertainties
The total of the system errors are within ±15 percent.
The uncertainties introduced by the nature of the sample include:
1. The particle size effect corrections
2. Degredation of the samples by the beam and in preparation
3. Hetrogeneous distribution of mass across the substrate
The error in the lower stages, C through E, was within ±10 percent
from these effects, while the errors on the first two stages (A and B)
were within ±30 percent. The larger error band is due to the large
particle sizes. The values of Si and Al concentration for the first
stage (A) was ±40 percent. Larger errors are expected for the lighter
elements because of greater self-attenuation of the X-rays.
30
-------
The analysis was repeated for selected samples. It was found the
results were within the stated system error of ±15 percent.
The Crocker Laboratory has also participated in inter comparison of
trace element determinations of standard air pollution samples. In a
recent intercomparison, the technique yielded a ratio to accepted con-
centrations often elements of 1.033 ± 0.08 [Camp et al, 1975]. Thus,
the errors due to both the system and sample matrix are well within
the stated limits.
Plant Process Visiometer
The two major sources of error thought to be important for the instru-
ment were losses of particles in the sample probe and light losses in
the optical chamber.
Wall Losses of Particles in the Sampling Probe -
Wall deposition of particles.in the flow piping to the optical chamber was
due to simple sedimentation and Brownian and eddy diffusion in turbulent
flow regions. In addition, the bend in the sampling probe causes large
particles to impact on the outside wall of the turn. In an effort to mini-
mize these effects, the sample tube was selected to be of fairly large
inner diameter (about 1. 6 cm) which allowed a sample flow rate of 140
to 280 liters per minute.
Several theories describing these phenomena are available in the
literature. Each is defined for the entire size range of interest (0. 01 -
10 f-lm), but none is experimentally verified for the entire range. A
combination of these theoretical approaches were used to generate an
estimate of wall losses under the conditions encountered in the scrubber
evaluation. The details of these calculations are described in Appendix A.
The sampling probe was operated for near-isokinetic sampling, which
required a mean flow velocity of 15-21 m/sec (50-70 ft/sec). The pipe
flow Reynold's Number for this entire velocity range is on the order of
10*, indicating that turbulent flow occurred in all tests. However, the
turbulent flow is not thoroughly developed until 25-40 pipe diameters
downstream from the inlet [Schlichting, 1968], Despite the fact that the
right angle turn exists in the first 25 diameters of the PPV sampling
probe, it was assumed for the purposes of the sedimentation, Brownian
diffusion, and eddy diffusion calculations that the probe could be repre-
sented as a straight pipe with 40 diameters of laminar flow followed by
a varying length of turbulent flow. The effects of the turn were analyzed
separately and under the assumption of laminar flow.
31
-------
To ensure that the calculations would be conservative for the entire
flow velocity range, the upper velocity boundary was used for the
turbulent deposition claculations (where deposition increases with in-
creasing velocity), while the lower velocity boundary was used for
sedimentation and laminar diffusion calculations (where deposition
increases -with decreasing velocity).
A cumulative loss fraction as a function of sampling probe length was
computed assuming that the 40 diameters of laminar diffusion/sedimen-
tation flow were followed by the 3. 6 cm radius turn and then by varying
lengths of fully developed turbulent flow. The cumulative loss fraction,
referenced to the probe inlet concentration, can thus be defined as
LFC =!-(!- LFB) (1 - LFR) (1 - LFT) (4)
where ^F = cumulative loss fraction
LF = loss fraction due to laminar diffusion and
s edimentation
LF = loss fraction due to impaction at bend
R
LF = loss fraction due to turbulent deposition.
T
Table 2 is a summary of the results. The largest particle size for
which LFR = 0 (5.8 jUm) and the particle size often referenced in the
literature (3. 0 £im) are included as special cases.
For all calculations, the ambient pressure was considered to be
atmospheric, 1524 m (5000 ft), the ambient temperature to be 120 °C
(250 °F), and the ambient density to be the atmospheric value correc-
ted to the above temperature. The tube walls have been considered
100 percent effective in retaining the particles once deposited.
For 0.01 Jim, the losses are due to Brownian diffusion in the laminar
region with no losses in the bend or the turbulent region.
The 0. 1 jLlm losses are due to Brownian diffusion in the turbulent
region where the laminar sublayer is quite small.
32
-------
The lack of losses for 1. 0 jUm is due to the inability of the relatively
large particle to diffuse rapidly in the laminar range and its inability
to penetrate the laminar sublayer rapidly in the turbulent case. The
latter occurs because the low inertia of the 1. 0 jLim particles makes
them subject to the random fluctuations of the turbulent buffer and
core regions.
For particles larger than this, simple sedimentation occurs in the
laminar flow regime and the increased particle inertia carries them
to the walls in turbulent flow.
Table 2. CUMULATIVE LOSS FRACTION IN FLOW PIPING
(Percent)
Particle
Diameter
(ttm)
0.01
0.1
1.0
3.0
5.8
10.0
Laminar
Portion
0.3
0.0
0.0
0.1
0.3
0.8
Turn
0.3
0.0
0.0
0.1
0.3
70.2
Total Pipe Length (m)
1.2
0.3
0.1
0.0
1.0
15.6
83.8
1.8
0.3
0.1
0.0
1.9
28.5
91.2
2.4
0.3
0.2
0.0
2.7
39.5
95.2
3
0.3
0.2
0.0
3.6
48.8
97.4
3.6
0.3
0. 3
0.0
4.4
56.6
98.6
33
-------
These calculations are consistent with the wall deposition observed dur-
ing the test. As long as the temperature was maintained above the dew
point of the stack gas, little evidence of particle deposition on the walls
•was observed. Also, it is suspected that the large particles predicted
to be lost to the walls are resuspended after deposition.
Light Losses -
The light loss errors in the PPV resulted from two sources: the angular
integration truncation errors and the secondary attenuation error.
The angular integration truncation error results from the optical geom-
etry. The instrument would be very long to measure the light scattered
from 0 to 180°. In a practical instrument, the light scattered from 10
to 165° is measured. The error is also a function of the particle size
distribution in addition to the instrumental geometry. Ensor et al [1974]
reported that calculated errors for various size distributions are ±20
percent of scattering coefficient.
Secondary attenuation may occur in concentrated aerosol when the
scattered light is attenuated from the scattering volume to the detector.
The error is a function of the distance from the light source to the
detector and the concentration of the aerosol. For the scattering co-
efficient of less than 0. 2 m"1 measured during the test, the error was
less than 5 percent.
34
-------
SECTION IV
TEST RESULTS
TEST SUMMARY
The test began on November 3, with the setting up of the trailer,
motel laboratory, and installation of the Plant Process Visiometers.
The testing of the inlet ducts (Phase 1) was started with two impactor
trains and two in-stack filter trains.
The sampling of the outlets (Phase 2) was started on November 14.
It was found that striking differences in concentration existed between
the three ducts. A Method 5 test was conducted on November 20 on
duct B at the same time as an impactor test.
The simultaneous inlet-outlet tests (Phase 3) were started on
November 20 with an APT crew operating the diffusion battery.
On November 22, however, the fuel was switched from coal to gas
to allow plant personnel to perform simple maintenance on the
scrubber booster fan. The plant operating personnel decided to
stay on natural gas as long as possible to perform other maintenance.
It was decided at that time to remove the PPVs and complete the test
work at a later time.
The Phase 3 activities were completed during December 9 to 13.
The tests included the sampling for count, elemental composition,
and mass tests.
All test phases were successful and provided a useful data base which
was systematically accumulated during the test.
DISTRIBUTION OF MASS LOADING BETWEEN DUCTS
Sampling
Inlet tests typically consisted of two impactors and two in-stack
filter holders run concurrently, one in each duct. Sampling times
ran between 5 and 10 minutes and were varied somewhat, depending
35
-------
on measured mass loading, flue gas velocities, and the ratio of
natural gas to coal being used as fuel by the power plant.
At the outlets, the filter holders were dispensed with in favor of
impactors. Sample times ranged from 10-20 minutes. The impac-
tors were placed in heating jackets and heated to 17-28° C (30-50° F)
above the temperature of the flue gas to prevent condensation of water.
Near the end of the outlet test period, the flue gas velocity in duct A
dropped below 10 m/sec (30 ft/sec) and sampling in that duct was sus-
pended.
Analysis
For the analysis, mass concentrations per unit volume were calcu-
lated for all ducts based on the above tests and an average mass loading
was calculated for each duct. The ratio between the mean mass loading
and the mass loading in each duct was calculated. The results are
shown in Table 3.
At the inlets, at least one sample was taken in each available port.
However, testing was not extensive enough to determine a mass
distribution within each duct. At the outlets, sample positions were
restricted due to the geometry of the ducts and the sampling ports.
The inlets were reasonable uniform in mass concentration. On the
average, the variation was -within 30 percent. Individual sample
variation could be as large as 2:1. It was felt that this variation was
random and would average out -with consistent testing of a single
inlet duct during the inlet-outlet tests.
The scrubber outlet ducts, however, had considerable reproducible
differences. The primary cause of the variation between outlet ducts
was the plugging of the air reheater in duct A. The imbalance in the
flows is shown by the velocity profiles in Figure 8. The three scrubber
sections are independent and it was felt that the "B" compartment had
performance most representative of normal operation.
After the first test segment, the plant maintenance personnel inspected
the scrubber on November 30. Figure 9 shows a summary of their
findings.
During the inspection of the scrubber, it was found that 2 of 9 com-
partments in C and 3 of 36 compartments in B were empty which
may also explain some of the variation in efficiency.
36
-------
Table 3. RATIO OF DAILY MASS CONCENTRATION IN EACH
DUCT TO THE AVERAGE MASS CONCENTRATION
Inlet Ducts
Date Time
11/7 1530
11/8 1040
1430
11/9 1130
1235
1430
11/11 1000
1300
11/12 1030
1250
11/13 0953
1201
1428
Average
Standard
Deviation
IV
1.25
1.17
0.76
0.56
1.13
0.75
0.69
0.74
0.77
1.35
0.90
0.92
0.26
in
0.78
0.94
0.94
0.78
1.00
1.69
1.95
2.12
1.83
1.33
0.72
0.71
1.23
0.53
II
1.53
1.06
0.89
1.58
0.67
0.93
0.51
0.81
0.85
0.60
0.48
0.90
0.37
I
0.43
1.00
0.85
1.44
0.51
0.37
0.68
0.63
1.06
1.33
1.91
0.93
0.48
Mass Cone.
mg/DSM3
569
512
558
405
739
511
976
814
948
1791
875
1268
1343
Outlet Ducts
11/19 1021
1133
1351
11/18 1027
1221
1402
11/15 1025
1208
1429
Average
Standard
Deviation
A
1.14
1.53
1.63
0.45
2.15
1.47
1.40
0.57
JB
0.72
0.69
0.70
0.59
0.67
0.63
1.24
0.37
1.15
0.75
0.27
j3
1.55
1.21
1. 10
2. 55
0.67
1.44
0.41
2.53
0. 63
1.34
0.78
133
136
205
174
85
171
158
128
87
aDry Standard Conditions 21. 1° C, 760. mm Hg
37
-------
Wall
0.5-
Duct A
Duct B
Q Duct C
10 15 20
VELOCITY, m/sec, STACK CONDITIONS
75-236
Fig. 8. Velocity traverse inlet ducts, 11/18
-------
Top
OK
OK
OK
OK
OK
OK
OK
OK
OK
L OK
OK
OK
OK
OK
OK
OK
MX
2 x Normal
Middle
OK
OK
OK
MX
a
2 x Normal
MX
2 x Normal
OK
OK
OK
OK
OK
a
OK
OK
OK
OK
00
vD
Bottom
OK
OK
OK
OK
a
1 1/2 x Normal?
MX
OK
OK
OK
a
1 1/2 x Normal?
OK
a
1/2 x Normal
MX
2 x Normal
OK
« North
Notes:
Section A - 1' x 2' hole through demister; demister spray nozzle had fallen off.
a. Xhe compartments were not visible from inspection plate.
b. 4" wide plate by inspection door is loose.
c. Loose vertical grid.
d. Vertical grid open.
Section C - 2 bolts had fallen out of recirculation spray nozzles; no evidence of damage to lining.
\!T - Indicates that compartment is empty of packing
Figure 9. Results of inspection of scrubber packing compartments
-------
Before the final sampling segment in December, the plant personnel
performed minor maintenance. The packing in section C was redis-
tributed; however, B section was not repaired. Also, the clogged
reheater was cleaned to some extent by drying the deposit and dis-
lodging with the soot blowers. This was partially successful, as
indicated with the December velocity transverses in Appendix B.
SCRUBBER EFFICIENCY
Introduction
The Phase 3 tests were used to compute the efficiency of the scrubber.
Sufficient data were taken to allow selection of the runs taken during
steady-state plant conditions. The data used in the efficiency deter-
minations are summarized in Table 4. The diffusion battery tests
were restricted to duct B at the outlet because of the relatively
nominal behavior of that section of the scrubber.
Total Mass Collection Efficiency
The mass collection efficiency was computed using only the cascade
impactor data. The results were summarized along -with some control
room data in Table 4. The pressure drop across the system was
reported to indicate the magnitude of the effect of the existence of the
air reheaters. The outlet gas flow was the total for the system as
determined from the velocity traverses. One of the unexpected
results was the lack of correlation of efficiency on the pressure drop.
The average efficiency of the December tests was 92. percent,
slightly lower than the design efficiency of 95 percent.
Mass Penetration as a Function of Particle Diameter
The collection efficiency of the scrubber as a function of particle
size is of interest because the particle effects (opacity, etc. ) are a
function of particle size. A convenient way of presenting the results
is in the form of penetration defined by
—7 mass concentration out
mass concentration in
The fractional efficiency is simply
E = 1 - Pt. (6)
40
-------
Table 4. SCRUBBER COLLECTION EFFICIENCY
DATE
11/20
11/21
12/10b
12/11
12/12
LOAD
mw
166
164
157
160
160
| SECTION A
r
Oa
Percent
3.6
3.4
3.4
3.0
2.6
OUTLET | .
CAS FLOW
ACTUAL
m" /hr
a
a
9.47 x JO5
10. 2 x 10*
8.78 x 105
L. i'
SYSTEM.
cmH;, O
41
39
36
38
38
BFD ! MIST
1
cmH2O
9.9
9.6
15.2
14.7
14.7
cmH^O
0.76
0.76
1.7
1.5
1.8
EFF.
ND
ND
96.3
96.4
79.6
SECTION B
SYSTEiV
cmHaO
45
43
41
42
44
AP
BED
cmH3O
25
18
20.8
2Z. 1
22.9
AP
MIST
ELLM.IN.
cmMjO
2.5
1.8
2.5
3.2
2. 5
EFF.
84.7
89.9
92.6
93.2
93. 1
SECTION C
SYSTEM
cmHsO
46
44
41
44
46
BED
cmH2O
24
20
18.5
22. 4
24. 1
<1 P
MIST
EL1MIN.
cmH8O
8.3
EFF.
ND
3.8
2.5
3.8
ND
86.9
96.7
92.1
Full velocity traverses were not taken.
The control room data •were incomplete. Interviews, data from other days and the log
book were used to supplement available information.
-------
Methods of Calculation -
Scrubber penetration as a function of particle size is computed from
data on the inlet and outlet particle size distributions and concentra-
tiosn. The major steps involved in the computation are as follows:
1. Reduce cascade impact or data to the form of cumulative
particle mass concentration for each impactor cut diameter.
2. Convert diffusion battery data from number distribution to
mass distribution and then plot cumulative mass concentration
against particle diameter as for the cascade impactor data.
3. Determine the slopes of the cumulative mass distribution
curves at several values of particle diameter for scrubber
inlet and outlet by a graphical technique and then compute
penetration at each particle diameter.
Penetration analysis required that simultaneous inlet-outlet cascade
impactor runs were selected. Table 5 is a list of runs used in
calculating the penetrations.
Screen Diffusion Battery Data -
Tests were limited to the duct B and were performed as indicated
in Table 6. As the cascade impactor runs were of shorter duration
than the diffusion battery runs, simultaneous matching of results was
difficult. Penetration comparison required averaging inlet and outlet
data from the diffusion battery (nonsimultaneous) and averaging the
cascade impactor runs (simultaneous) over the entire day.
Of 15 runs taken, six were found suitable for comparison with cascade
impactor analyses. No test difficulties were encountered in these
runs and operating conditions of the boiler were indicated to be steady
by the plant instrumentation. Table 6 includes diffusion battery and
cascade impactor comparable runs.
Data for the runs in Table 6 were averaged and converted to overall
particle penetration versus screen solidarity factor by the ratio of
outlet to inlet concentration for varying thickness of screen. Screen
solidarity factor is a semi-emperical quantity which is developed
by laboratory calibration and which is dependent upon the cumulative
number of screens. A graphical stripping technique developed by
Sinclair [1972] was used in conjunction with laboratory calibrations
to reduce the penetration data to a count-basis size distribution.
42
-------
Table 5. DATA PAIRS USED IN PENETRATIONS
DATE
11/20
11/21
12/10
12/11 .
12/12
TIME
1030
1343
1110
1207
1116
1530
1617
1224
1215
1240
1445
1624
1140
1300
1110
1320
919
INLET
RUN
56
55
60
113
114
119
120
8
123
124
127
12
133
135
134
136
13
LOCATION
8
8
8
8
8
8
13
13
13
13
8
13
8
8
8
8
13
TIME
1034
1328
1107
1142
1110
1530
1630
1628
1215
1445
1446
1108
1140
1300
1113
1300
1529
RUN
53
57
61
110
109
116
118
9
122
125
126
10
129
132
130
131
15
OUTLET
LOCATION
B
B
B
A.
B
B
C
B
C
B
A.
B
B
B
A.
C
B
COMMENTS
Elem. Sampling
Elem. Sampling
Elem. Sampling
Elem. Sampling
Diffusion Battery
Elem. Sampling
Diffusion Battery
Diffusion Battery
-------
Table 6. CNC DATA FOR DIFFUSION BATTERY TESTS
RUN
NO.
8
9
10
12
13
15
READING
SET
1
2
3
4
1
1
2
3
4
1
2
3
1
2
3
4
1
2
3
4
CONCENTRATION AT INDICATED
SCREEN SOLIDITY FACTOR,
PARTICLES /cm3 x ICT4
Solidity Factor
0 13 26 40
4.0
2.97
2.80
2.57
69.3
35.2
31.7
35.3
31.0
5.27
4.27
3.30
4.80
3.87
2.97
2.80
7.83
7.30
7.20
7.37
3.3
2.17
1.87
1.73
39.0
15.7
12.7
16.0
14.0
4.30
3.50
2.63
3.40
2.87
2.03
1.90
4.70
4.43
3.93
4.07
2.13
1.53
1.23
1.33
32.3
11.7
8.2
10.7
7.9
3.66
2.83
1.97
2,87
2.23
1.70
1.53
2.60
2.37
3.37
2.47
1.33
0.87
0.77
0.70
28.3
6.9
6.1
7.1
5.8
2.87
1.87
1.30
1.97
1.57
1.17
1.17
1.63
1.70
1.50
1.60
44
-------
Cumulative mass loading was determined by a combination of graphi-
cal integration, density, and overall count using a particle density
of 1. 0 g/cm3 . Table 7 contains the comparison of count-based total
mass loading with the gravimetric analysis of the diffusion battery
bypass filter. Effects of density on calculations are included and
appear to agree optimally in the region of 2. 0 g/cm .
The count bias distributions on the plots of cumulative mass loadings
for both inlet and outlet runs for each day are in Appendix B. Overall
penetration for the entire particle size distribution is defined as:
Pt =
1
W
r
Pt. dW
i
(7)
where W^. is the total particle mass and Pt^ is the penetration for
particle diameter, dp^, and it is given by:
f (d .) outlet
pt = El
i f (d .) inlet
P1
[dW
d (d .)
pi .
r dw
d (d .)
L pi .<
outlet
inlet
(8)
[dW "I
, . .. — r
d (di) J
is the slope of the cumulative mass versus
particle diameter curve at d . and equals f (d .).
P1 PI
By measuring the slope at each given d^ for both inlet and outlet,
values for Ptj were determined as a function of dp^.
45
-------
Table 7. COMPARISON OF COUNT-BASIS VERSUS
GRAVIMETRIC- BASIS TOTAL MASS LOADING
RUN
NO.
8
9
10
12
13
15
INLET/
OUTLET
Inlet
Outlet
Outlet
Inlet
Inlet
Outlet
PRE-
CUTTER
d-50
Jim
0.24
0.26
0.26
0. 24
0.27
0.28
TOTAL MASS LOADING, Mg/DNm3 a
VARIOUS PARTICLE DENSITIES
1.0 g/cm3
12. 3
1.84
13. 1
28. 3
2.31
0.28
2.0 g/cm3
24.6
3. 68
26.2
56.6
4.62
0.56
3.0 g/cm3
36.9
5. 52
39. 3
84.9
6.93
0. 84
FINAL FILTER
GRAVIMETRIC
ANALYSIS
27.9
3.23
103.0
43.3
2. 71
0.85
Normal conditions, 0° C, 760 mm Hg
-------
Particle size distributions by number for the size range smaller than
about 0. 3 ^im (the lowest cascade impactor cut diameter) were obtained
from screen diffusion battery data by means of methods described in
the previous nection. Conversion of number distribution to mass dis-
tribution is necessary in order to put the diffusion battery and cascade
impactor data on the same basis. The method used to make this conver-
sion is a graphical integration of the following equation:
N /"Npi dm /N x 100
Mpi = wo J dS2 d i^T— I <9>
O p \ pt
where N = cumulative number concentration of particles
smaller than "d ", no. /cm3
P
N = total number concentration of particles,
Pt / 3
no. /cm
d = particle diameter, //m
d . = a specific particle diameter, (Am
m = mass of particles in the infinitesimal size
P range (d + ddp), g
M . = cumulative mass concentration of particles
P1 smaller than "d ", g/cm3.
The quantity (dmp/dNp) is simply the mass per particle of diameter
"dp". The quantity (N_ x 100/N j.) is the number percent of particles
smaller than "dp". Thus, equation (7) can be evaluated from a plot
of mass per particle versus cumulative number percent of particles,
both quantities being evaluated at the same particle diameter to
provide a point on the plot. The total and cumulative number concen-
tration data are obtained as described previously.
47
-------
Penetration -
Equations (7) and (8) define overall penetration and techniques described
previously and were used in calculation of penetration versus cut size.
Penetrations for the Cascade impactor and the diffusion battery were
computed separately and then plotted together. The reason for this is
that while the relationship between cumulative mass concentration and
particle size obtained from diffusion battery data depends on particle
density, the penetration does not. The slopes of the cumulative mass
concentration plots for the inlet and the outlet are both proportional to
particle density. Thus, the ratio of the slopes (i. e. , the penetration
is independent of density because it cancels out. In the comparison
of cascade impactor and diffusion battery penetration data, however,
there is still some dependency on the value taken for particle density
because particle size must be computed from aerodynamic size. This
introduces an influence of the square root of particle density.
Presentation of Results -
The results for each run are found in Appendix B. The combined
cascade impactor and diffusion battery penetrations were determined
using a daily average of all simultaneous runs (Figures 10, 11, and
12).
Generally, the size distributions and penetrations were consistent,
though loadings fluctuated considerably. The maximum penetration
(minimum efficiency) -was achieved in the region of 0. 2 f«lm actual
diameter, similar to results for another scrubber as reported by
Sparks et al [1974].
Elemental Chemical Analysis
Introduction -
The measurement of the concentrations of a number of elements was
intended mainly to provide data to aid in the interpretation of the
scrubber performance. It was not planned to perform elemental
balances or determine emission factors. The samples were taken
during December 10-11, 1974.
Results -
The analysis results for 29 elements are tabulated infZg/m3 as a
function of particle diameter in Appendix C. The data were interpreted
48
-------
1.0
:
c
i—:
EH
U
;
o
-
-
::
^
-
,-
_
U
M
H
-
•
-
0.1
Q.01
DIFFUSION BATTERY RUNS #8 f, #9
IMPACTOR RUNS #110 $ #113
LJ'Ys A IMPACTOR RUNS #109 $ #114
IMPACTOR RUNS #116 f, #119
:;-; O IMPACTOR RUNS #120 § #118
I I I If ! l_l I "I "I M M
Q.04 0.07 0.1 0.2 0.5 1.0
PARTICLE DIAMETER, /im
2.0
5.0
Figure 10. Combined penetrations for diffusion battery
and cascade impactor (December 10, 1974)
49
-------
1.0 —
H
U
z,
o
H
w
2
W
w
J
U
A DIFFUSION BATTERY RUNS
S ?15
VIMPACTOR RUNS #122 5 #123
O IMPACTOR RUN'S #124 5 #125
IMPACTOR RUNS #127 5 #126
0.01
0.02
0.05 0.10 0.3 0.5 1.0
PARTICLE DIAMETER,
3.0
Figure 11. Combined penetrations of diffusion battery and cascade
impactor (December 11, 1974)
50
-------
1.0
EH
U
:
O
M
H
EH
-
.'
-
-
2
U
—
-
-
<
-
0.1
m
0.0 I
O
A
O
V
DIFFUSION BATTERY RUNS #10 § #12
IMPACTOR RUNS #129 f, #133 B 1140
IMPACTOR RUNS #132 $ #135 B1300
IMPACTOR RUNS #130 f, #134 A 1113
IMPACTOR RUNS 0131 5 #136 C 1300
tiri" ' L_J I I I I Ml
/\ h
0.03 0.05
0.10 0.5 0.5
PARTICLE DIAMETER,
3.0 5.0
Figure I 2. Combined penetrations for diffusion battery and
cascade impactor (December 12, 1974)
-------
by determining the relative changes in the chemical nature of the fly
ash as a function of size and the elemental penetration through the
scrubber.
The elemental concentration is ratioed to Si to indicate the relative
changes in the character of the fly ash as a function of size. Si was
used as the reference element for the following reasons:
1. It is the most abundant element in the Earth's crust and the
major component of fly ash.
2. It is a relatively inert species in the fly ash and should be
present as Si Oa- Thus, it can be used as a tracer.
The elemental ratios were computed by first calculating an average
concentration (ng/m3) for each element and then dividing by the
average concentration of Si. In the tables, the elements below
detectable concentrations are indicated by a dash. The changes in the
ratio to Si indicate the variation in the chemical nature of the fly ash.
The elemental ratios for the inlet of the scrubber are shown in
Table 8. The infrequent elements were omitted from the table for
simplicity. There is enrichment for the elements S, Cu, and Zn
similar to that reported by Davidson et al [1974] and Kaakinen et al
[1974]. The explanation advanced for this enrichment is during
combustion the volatile elements evaporate and then condense on
the more inert materials when the stack gases cool. The heavier
elements are present in small concentrations near the detectability
limits of the technique and show indefinite trends.
In Table 9, the elemental ratios are shown for the exhaust of the
scrubber. There is again enrichment for S, Cu, and Zn. The
increase in S may have resulted in part from gas to particle conver-
sion within the scrubber. There also appears an enrichment of the
soluble elements such as K and Ca.
The enrichment of the exhaust of the scrubber as a function of particle
size may be due to the entrainment of mist containing soluble elements.
The entrainment of material through the mist eliminator has been
reported by Statnick and Drehmel [1974] and Johnson and Statnick
[1974].
The penetration of the elements through the scrubber was computed
for December 10, 1974, with procedures similar to those used for
the mass distributions. The following operations were performed:
52
-------
Table 8. Ratio of elemental concentrations relative to Si for six inlet tests.
(JO
Mean Particle
Size Jim
30
15
6.0
2.4
1.5
0.65
0.37
Filter
Element
Al
S
K
Ca
Ti
V
Mn
Fe
Ni
Cu
Zn
Se
Sr
Pt
Au
Hg
Pb
0.52
0.032
0.049
0.32
0.039
0.0049
0.00004
0.22
0.0026
0.0027
0.0007
--
0.00031
0.0004
0.00008
0.0003
--
0.52
_ _
0.052
0.39
0.051
0.0054
0.00004
0.29
0.0071
0.0061
0.0021
0.00005
0.0013
0.0003
0.00005
0.0003
--
0.65
—
0.066
0.56
0.073
0.0086
0.00005
0. 50
0.011
0.0024
0.00004
0.0004
0. 00001
0.00005
0.0005
0.041
0.65
0.071
0. 51
0.070
0.0093
0.00007
0.52
—
0.0061
0.0062
--
0.0004
0.0003
0.00004
0.0004
0.013
0.59
--
0.077
0.59
0.090
0.027
0.00014
0.67
0.011
0.011
0.0083
--
0.0004
0.0003
--
0.0002
--
0.55
0.048
0.048
0.72
0. 12
0.066
0.0003
0.73
0.036
0.016
0.020
0.0002
0.0005
0.0013
--
0.0006
--
0.52
0.066
0.049
0.66
0.089
0.013
0.0002
0.52
0.012
0.032
0. 12
--
0.0003
--
--
0.0003
—
0.35
0. 30
0.026
0.89
0. 17
0. 12
--
0.54
__
0.20
0.48
--
--
--
--
--
—
The elements Na, Mg, Cl, Cr, Co, As, Br, Rb, Zr, Ag, Ba were generally below the detection limits
of the technique.
-- indicates the element was below the detection limit.
-------
Table 9. Ratio of elemental concentrations relative to Si for ten outlet tests.
Mean Particle
Size urn
Element
Al
S
K
Ca
Ti
V
Mn
Fe
Ni
Cu
Zn
Se
Sr
Pt
Au
Hg
Pb
30
15
6. 0
2.4
1. 5
0.65
0. 37
Filter
0.49
0.49
0. 30
0. 73
0. 30
0.40
_ _
0.66
0. 062
0.097
0. 059
_ -
HI <•*
_ —
. _
«• —
__
0. 59
0.27
0.42
0.20
0. 34
_ _
0. 51
0. 089
0.066
0. 14
_ -
_ _
_ _
_ _
_ _
— tm
0. 55
0. 088
0. 086
0. 64
0. 094
0. 11
0. 0018
0. 51
0. 090
0. 044
--
_ _
_ _
0. 007
_ _
_ _
0. 54
0.084
0. 16
0. 53
0.080
0.030
0.0009
0. 54
0.607
0.026
•• M
--
0. 002
0. 601
0.002
0. 002
_ —
0. 59
0. 045
0. 067
0. 61
0.093
0. 031
0. 0006
0. 61
0. 007
0.015
0.014
0. 0008
0. 002
0. 001
0. 002
— —
0.59
0.038
0.052
0.71
0.097
0.029
0. 0006
0.62
0.072
0.012
0.015
--
0. 002
--
0.0009
0. 002
— _
0.44
0. 16
0. 040
0. 65
0. 11
0. 046
0. 0006
0. 59
0. 010
0. 033
0. 084
0. 0005
0. 002
0. 0008
—
0. 004
0. 12
0. 30
5.2
0. 081
2. 0
0.27
--
0. 0041
3. 7
0. 16
4.9
3.8
0. 002
0.005
0. 007
--
0. 002
0.47
The elements Na, Mg, Cl, Cr, Co, As, Br, Rb, Zr, Ag, Ba were generally below the detection limits of
the technique.
--indicates the element was below the detection limit.
-------
1. The elemental data were averaged for the inlet and outlet using
the same runs used for the mass penetration calculations.
2. The cumulative "smaller than" elemental concentration as a
function of particle size was plotted for the inlets and outlets
averaged runs.
3. The ratio of the slope of the cumulative curves for the inlet
and outlet was used to compute the penetration for specific
particle diameters.
The penetration of the elements is shown in Figure 13. The mass
penetration has been plotted on the graph for reference. The striking
implication of the elemental results is the large difference in pene-
tration depending on chemical nature of the aerosol. Si and Al
probably existing as insoluble oxides have a very low penetration
through the scrubber, whereas the soluble elements have much
higher penetration in the submicron region as well as a suggestion
of a bimodal penetration, which may be due to entrainment through
the scrubber mist eliminators.
The enrichment of the soluble elements such as K, Ca, Mn, Ni, Cu,
and Zn relative to Si for both the large and small particles was
unexpected. A possible explanation may be in consideration of
collection mechanisms in the scrubber. The TCA scrubber contains
a fluidized bed packed with plastic balls 3. 8 cm in diameter. The
scrubbing liquor is sprayed upon the packing. Calvert et al [1972]
reported that the collection of particles in a TCA scrubber has been
attributed to a bubble mechanism. The bubbles are generated as the
stack gas moves up through the wetted packing. Junge [1963 ]
summarized the process where a bubble upon breaking will form a
bimodal distribution of droplets. The small particle fraction results
from the fragments from the bubble film and the coarse particle
fraction results from jetting produced during collapse of the bubble.
In Table 10, the elemental penetration is compared to the mass
penetration. Again, the large difference between penetration of Al
and Si and the other elements is apparent. It also appears that the
scrubber is a source of sulfur-containing aerosols possibly in part
from gas to solid phase reactions. The soluble elements, such as
Cu, Zn, and Cr, appear to be generated from the evaporation of the
scrubber liquor.
55
-------
10° —
H
U
O
i-H
H
H
W
2;
W
10
PARTICLE DIAMETER, /im
75-288
Figure 13. Scrubber penetrations for selected elements
56
-------
Table 10. PENETRATION OF THE ELEMENTS THROUGH THE
SCRUBBER FOR DECEMBER 10, 1974
Element
Penetration
Average Outlet
Concentrations
Micrograms/DSm3
Al
Si
S
K
Ca
Ti
V
Cr
Fe
Ni
Cu
Zn
Br
Pb
For All Elements
Total Mass
0.029
0.033
3.4*
0.043
0.059
0.073
0.14
1.10a
0.18
0.95
2.9a
1.5a
0.28
0.64
0.108
0.074
326
658
1030
50
508
96
27
57
1500
33
668
501
5.7
120
Penetrations greater than 1 indicate generation of particles.
'Dry Standard, 21.1 ° C, 760 mm Hg
57
-------
Discussion
Scrubber Performance -
The scrubber performance results were analyzed in depth for trends
and to allow comparison to data in the literature.
Examination of the particle penetration data for each simultaneous
pair of inlet and outlet runs shows a wide range of results, as
summarized in the following table.
TABLE 11. PARTICLE PENETRATION SUMMARY
RUN
IN
56
55
60
114
119
121
125
133
135
124
113
127
134
115
120
123
136
NO.
OUT
53
57
61
109
116
123
127
129
132
125
110
126
130
119
118
122
131
DUCT
B
B
B
B
B
B
B
B
B
B
A
A
A
C
C
C
C
"PC,*
/im
1.5
1.1
0.8
0.8
1.0
0.8
<0.5
0.8
0.8
0.6
1.0
0.8
2.0
< 0.5
0.6
0.7
1.1
AP
cmHa O
23.0
23.0
23.0
23.0
23.0
23.0
23.0
23.0
23.0
23.0
--
15.0
9.0
25.0
--
25.0
24.0
F. out
F. in
0. 31
0.81
1.2
2.9
0. 39
0.55
1.2
2.0
0.47
3.1
0.81
0.41
6.7
0.76
1.0
1.1
3.5
a
Scrubber cut (50 percent penetration) diameter.
b
Ratio of outlet filter to inlet filter particle concentrations
(mg/DSm3)/(mg/DSm3).
58
-------
The scrubber performance cut diameter (i.e., particle diameter
at 50 percent penetration), used to characterize efficiency, varied
from less than 0. 6 ^m to 2. 0 /1m. No pattern of correlation between
cut diameter and other parameters such as pressure drop was found.
Thus, the variation was due to a combination of system fluctuations
and measurement errors.
Penetrations found in this study are much higher than those reported
in a previous study of the same scrubber [Calvert et al, 1974] and
of other mobile bed scrubber on a coal-fired power plant [Statnick
and Drehmel, 1974]. For example, Calvert et al reported a cut
diameter of about 0. 35 jltm and a penetration at 1. 0 /1m of about 8
percent. Statnick and Drehmel reported that, for 25 cm of water
scrubber pressure drop, penetration did not exceed 5 percent for
any particle size and was about 2 for 1.0 /lm particle diameter.
These and some other points are compared in the following table
with representative results from the present study.
TABLE 12. COMPARISON OF MOBILE BED STUDIES
T1.T._crT,T_ArTlot5C , PENETRATION AT PARTICLE
INVESTIGATORS dpc, Mm DIAMETER SHOWN
0.5/Ltm 0. 8 /um 1. 0 pirn 2. 0 /lm
Presenta 0.8 0.8 0.5 0.4 0.15
Calvert et al
[1974] 0.35 0.3 0.15 0.08 0.02
Statnick and
Drehmel [1974] -- 0.07 0.03 0.02 0.002
3.
Approximate mean values for all runs, exclusive of 56/53 and
134/130.
The mean performance cut size found in this study is consistent
with that predicted by means of Calvert's [1974] correlation of cut
diameter with scrubber pressure drop. A venturi, or gas-atomizing,
scrubber would have a 0. 8 /lm cut diameter at 23 cm of water pressure
59
-------
drop. This corresponds to about 0.7 £lm for particle density of
1. 0 g/cm3. As discussed by Calvert et al [1974] a spray type of
collection mechanism seems more appropriate than others, such as
collection on packing spheres or in a packed bed.
Evidence of high outlet particle concentration due to entrainment
from the scrubber weighs against one considering the agreement
between predicted and experimental cut diameters to be anything
more than coincidence. Facts which indicate the presence of outlet
particles introduced by entrainment are as follows:
1. Outlet filter loadings are higher than inlets, based on the
same gas sample volume, for many of the tests.
2. Penetrations in the present study are higher than those
found by others.
3. Variations in penetration are not related to gas flow
rate, pressure drop, or other known parameters, but
can be attributed to variable entrainment.
4. Penetrations for scrubber section "A" are the same as
for section "B" despite the gas pressure drop for "A"
being about half that for "B".
5. Reheater and entrainment separator operating problems
occurred during the test.
6. Elemental analyses of inlet and outlet particles show an
apparent "generation" of particles containing soluble
elements as described in the previous section.
The overall conclusion is that the scrubber performance data
obtained in this study are specific for the operating factors and
scrubber condition which existed during the test period. It is not
possible to establish a general mobile bed scrubber performance
model from these data because of the overshadowing and undefined
influence of liquid entrainment.
Entrainment -
Both particle collection efficiency and entrainment are dependent on the
gas velocity through the mobile bed and on the state of motion of the bed.
Gas velocity is the parameter which has the greatest effect on the state
of motion of the bed. Assuming that the flue gas is saturated with water
vapor at 52° C (125° F), the partial pressure of water vapor is about
100 mm Hg and the water vapor concentration would be about 16 percent
60
-------
by volume at a total pressure of 635 mm Hg. The flue gas flow rate dur-
ing the tests ranged about 1 x 10s Am3/hr (6 x 10 5 ACFM) at 52° C
(125° F) and 635 mm Hg.
Superficial gas velocity through the beds can be computed from the gas
flow rate and bed area. Beds "A" and "C" have 4. 58 m x 2. 7 m rectangu-
lar cross sections (area = 12. 7m*) and bed "B" has a 4. 58 m x 8. 37 m
cross section (area = 38. 3 m2 ). Thus, the total superficial cross sec-
tional area is 63 m and the average superficial gas velocity is 4. 5 m/
sec (14. 8 ft/sec).
A gas velocity of 4. 5 m/sec is higher than recommended, for several
reasons. To ensure proper fluidization, a velocity of 2.8 m/sec ±
20 percent is recommended. Research on pressure drop and state of
motion of the bed has shown that at about 3. 5 m/sec gas velocity there
is a change in characteristics and at 4. 5 m/sec it is quite pronounced.
Pressure drop increases and bed expansion increases to the point
where balls are held up against the top retainer rather than moving
freely.
Recent studies (presently unpublished) by APT, Inc. , have shown that
entrainment from a mobile bed scrubber increases when the gas ve-
locity exceeds about 3 m/sec, and it is severe when the velocity is
4 m/sec and higher. Extrapolation of the available data indicates
that at a scrubbing liquid flow rate of 1. 8 m3 /min - m and a super-
ficial gas velocity of 4. 5 m/sec the entrainment flow rate might be
roughly 1.5 to 2 percent of the scrubbing liquid flow rate. Thus, for
a bed area of 63 ma the entrainment rate might be about 2 m /min.
The significance of 2 m3 /min of entrainment can be illustrated by
assuming that the entrainment contains 15 percent solids and that
the entrainment separator is 99 percent efficient. The rate of solids
emission from the entrainment separator would be 3 Kg/min and the
concentration in the flue gas would be 0. 26 g/Nm3. Outlet loadings in
this test series ran about that magnitude and less.
It is not presently possible to predict the probable efficiency of the
entrainment separator because there are insufficient data available
on entrainment drop size from the mpbile bed in the high flow rate
range. However, the example given above illustrates the sensitivity
of outlet emission rate to the bed operating conditions and the effi-
ciency of the entrainment separator.
Reentrainment from the chevron type entrainment separator should
not have been severe because the superficial gas velocity of 3. 3 m/
sec (based on total separator area of 86 m ) is within the operating
61
-------
region for no or slight reentrainment. Irregularities such as plugging,
broken or distorted baffles, etc., could cause local flooding and entrain-
ment.
Particle collection can reasonably be expected to depend on gas velocity
and bed conditions but it is not presently possible to predict the relation-
ship. This is especially true when the fluidization of the bed may be
impaired by the high gas rate and the maldistribution of balls among the
bed sections.
ANALYSIS OF IN-STACK PLUME OPACITY
Data Reduction
The scattering coefficient was obtained from the strip charts and
corrected for drift. A tabulation of scattering coefficient and data from
impactor tests is shown in Table 13. The geometric mass mean diam-
eter and geometric standard deviation were determined with a least
square's fit to a log-normal size distrubution. The parameters of the
log-normal sized distribution were also determined graphically as
verification of the calculated results.
The analysis of these data consisted of comparing measured scattering
coefficient (bscat) with particle mass loadings and particle size dis-
tribution data obtained with the impactors. Figure 14 is a plot of
bgcat vs particle mass for the data shown in Table 13.
The data in Figure 14 show the two groups of points, those of the inlet
and those of the outlet. Averaged over the time period of the individual
tests, there appears to be little real variation in bscat indicating a
small change in average mass loading during the test. It should be
noted, however, that instantaneous bscat fluctuations were monitored
with the PPVs and were very prominent during apparent upset periods
(see Figure 14). A Bailey meter installed on the duct work leading to
the main stack exhibited similar peaks during upsets. However, the
Bailey meter and PPV were not compared directly because the PPV
monitored only duct B, while the Bailey measured a mixture of the
three ducts.
Theresults of a linear regression analysis of the scattering coefficient
data are in Table 14. The correlation of 0. 766 for a linear fit indi-
cated that 58. 7 percent of the variation in the data is explained. Part
of the unexplained variation in the regression was due to changes in
particle size distribution.
62
-------
Table 1 3.
PLANT PROCESS VISIOMETER AND
INERTIA L IMPACTOR DATA
Mass
b Vol. /bscat
TEST
Inlet
14
16
17
18
19
20
21
56
55
62
60
68
69
73
Outlet
37
40
41
46
43
51
63
53
57
58
61
67
70
74
DATE
11/11
11/11
11/11
11/12
11/12
11/12
11/12
11.20
11/20
11/21
11/21
11/21
11/21
11/22
11/18
11/18
11/18
11/19
11/19
11/19
11/20
11/20
11/20
11/21
11/21
11/21
11/21
11/22
TIME
0945
1240
1250
1015
1015
1245
1245
1030
1343
0957
1110
1320
1405
1000
Avg
1027
1221
1402
1031
1133
1351
1030
1034
1338
0955
1107
1317
1402
0954
Avg
m"1 mg/Am micron
0.
0.
0.
0.
0.
0.
0.
0.
0.
0.
0.
0.
0.
0.
0.
0.
0.
0.
0.
0.
0.
0.
0.
0.
0.
0.
0.
0.
0.
0.
088
077
077
100
100
120
120
116
110
107
117
117
128
139
108
036
036
033
037
035
040
042
042
032
031
030
032
032
047
0361
118
190
158
165
171
281
340
110
128
132
123
72.
64.
186
33.
18.
33.
31.
29.
45.
16.
23.
21.
13.
16.
15.
19.
21.
4
6
4
0
6
1
4
9
4
0
9
8
1
7
1
5
11.3
15.0
29.3
9.9
12.0
14.3
33. 1
3.1
6.8
4.5
8.3
2. 6
15.1
13.7
0.40
1.71
0.61
0.69
0.62
0.34
1.22
0.72
0.71
0.89
0.67
0.68
1.06
a
_g
3.51
3.00
4.00
3.72
3.77
3.66
5.22
3.28
3.75
1.30
3.57
6.05
3.94
3.19
7.34
6.3
8.74
6.11
4.04
10.83
4.11
5.31
6.00
4.74
10.0
3.24
3.20
0.
0.
0.
0.
0.
0.
0.
0.
0.
0.
0.
0.
0.
0.
0.
0.
0.
0.
0.
0.
0.
0.
0.
0.
-0.
0.
0.
r
c
991
994
987
990
992
996
993
961
978
289
989
974
981
993
964
975
983
971
966
973
936
974
941
975
515
988
115
cm3 /m2
1341
2468
2052
1650
1710
2341
2833
948
1163
1233
1051
619
505
1338
928
500
1018
841
840
1148
EPA Method 5
548
684
445
537
491
597
457
A density of 2.0 g/cm3 was assumed for the particles
a-Concentration at actual conditions.
b- coefficient of correlation for fit to log-normal size distribution.
63
-------
1.0 l-
a
H
H
U °'1
w
o
u
o
—
Pi
w
H
H
<
O
en
0.01
10
100
MASS CONCENTRATION, mg/Am;
^J
1000
75-OO8
Figure 14. Scattering coefficient as a function
of mass concentration
64
-------
F
j ..
-8
i
;__r v>>» -- — J_- j
~~—~- -li;~~rr~r. prT -Speed 1 in. /hr -—-i
"_-^:. lFull scale 0.06m"1-"_- -
I -zil••.:!.'.^Z...liFull scale 0.06m" ':."_-j;.
~Scrubber Outlet
._. .
i _5_ ..._. i -
' ' O! 1 .r-
::.-*,-^==.~
—*- ir— H •
-_J-.- - TS-- i_V—
[Speed 1 in. /hr
-^Full scale 0. 45m
Scrubber Inlet
Figure 15. Scattering coefficient measured upstream and
downstream
65
-------
Table 14. CORRELATION OF MASS CONCENTRATION WITH SCATTERING COEFFICIENT
A ^ Correlation Coefficient Std. Error of Estimate
Mass concentration, mg/m3 = A. + B (scattering coefficient, m"1)
-31.5 1683 0.766 56.2
Log (mass concentration, mg/m.3) = A. + B log (scattering coefficient, m"1)
3.64 1.57 0.897 0.197
Scattering coefficient, m"1 = A. + B (mass concentration, mg/m3)
0.0408 3 x 10"4 0.766 0.0256
Log (scattering coefficient, m"1) = A + B log (mass concentration, mg/m3)
- 2.11 0.514 0.897 0.113
-------
Scattering coefficient for a given mass loading is dependent on the
particle size distribution. Ensor and Pilat [1971] analytically related
mass loading and size distribution to plume opacity. Assuming a log
normal size distribution and using the Mie scattering equations, Ensor
and Pilat calculated a curve similar to the one drawn in Figure 16
which relates the ratio of particle vol/bscat to the geometric mass mean
diameter. The curve shown is for a log normal size distribution and a
geometric standard deviation of 4. Plotted on the same figure are data
from the PPV output compared with the geometric mean diameter values
derived from inertial impactor tests. The ratio of bscat to mass con-
centration is proportional to an extinction size and is a measure of the
effectiveness of a particle to obscure light. A minimum value indicates
maximum light scattering effect.
Discussion -
The particulate size distributions obtained from the impactor data are
not necessarily log normal. This probably accounts for the discrepancies
that exist between the PPV measurements and the curve presented by
Ensor and Pilat [1971]. The large difference between theory and the
measurements for particles less than 0.4 microns radius may be an
artifact introduced by the impactor. The smallest size resolved by the
impactors was 0. 4 microns diameter and, when submicron particles
are sampled, most of the material falls on the filter. The size distri-
butions are unreliable because they were determined by only one or
two data points. However, the data do appear to behave in a manner
similar to that which is predicted. There is a good consistency between
both instruments.
In summary:
1. The PPV measures scattering coefficient and can be applied
to a continuous indicator of mass loading.
2. The PPV is sensitive enough to monitor abrupt changes in
scattering coefficient which can be related to boiler and
scrubber upsets.
PARTICLE MORPHOLOGY
Introduction
Eight impactor tests were run with Mylar inserts for very short
sample times. The purpose was to obtain light partxcle deposxts,
permitting particle count and sizing.
67
-------
00
10.0 r
o
o
s
u
1.0
nS
IH
n)
0.1
0.1
(Mass/bscat) vs Geometric Mass Mean Radius
Theoretical curve with Geometric Standard Deviation = 4
Particle Density assumed to be 2 g/cm3
1.0 10.0
GEOMETRIC MASS MEAN RADIUS, dBO /2,
100. 0
Figure 16. Effect of particle size distribution on particle volume/b
[Ensor and Pilat, 1971]
-------
The Mylar inserts were dipped in an Apiezon L-benzene solution
placed on a collection disc, and baked at 143 °C (290 °F) for two hours.
Silver membrane filters of 0. 47 and 0. 8 ^l pore size were used as
impactor backup filters.
Impactors were inserted into the flue ducts pointing downstream and
allowed to come to stack temperature. After a 20 minute warrnup
period, the impactors -were turned into the flow and the samples were
taken. Sampling time ranged from 2 to 30 seconds, summarized in
Table 15. Four individual tests were run at the inlet and four at the
outlet.
Analysis
In the laboratory, the samples were optically evaluated as sets. An
inlet (Set 107) and an outlet (Set 103) sample set were chosen for
analysis based on particle densities collected on all stages. Initial
plans called for evaluation of the top three impactor stages, A, B,
and C, with an optical microscope, and the lower stages, D through
the filter, with a Scanning Electron Microscope (SEM). The nominal
cut sizes are shown in Table 1 .
For optical analysis, strips of the Mylar inserts were mounted on
glass slides. Samples were then projected onto an image processor
(Quantimet 720) screen through an optical transmission microscope.
The Quantimet 720 automatically sizes particles and tallies them in
preselected size categories. For a well-defined sample, an instan-
taneous documentation can be made. For a sparse sample, a special
pointer can be used to document individual particles.
The SEM work was performed by Hi-Rel Laboratories of San Marino,
California. A small section was cut from each sample and mounted on
a holder. They were then placed in a Varian Ve-10 vacuum evaporator
and 100-200 A of gold-palladium alloy was deposited on the surface.
They were documented with a Cambridge Model 54-10 SCM at magnifi-
cations of 500X to 5000X. Positive and negative photographs were
taken.
Some unexpected problems affected the outcome of the data The pro-
cedure for preparing the inserts (dipping an a greas,a soluUon baking
and allowing to cool slowly) may have caused growth of greaseIs
These crystals were about 10 ,m in size, ^^*
pa'rticle deposition patterns were
69
-------
Table I 5. TEST CONDITIONS
Duration
Sample Location (sec)
101 Outlet 30
102 Outlet 20
103a Outlet 10
104 Inlet 2
105 Inlet 10
106 Inlet 5
107a'b Inlet 3
108 Outlet 5
a
Samples evaluated.
Silver membrane filters with 0. 8 |Lt pore sizes were used.
70
-------
ill defined and number counts were low. It was difficult to distinguish
sampled aerosol from contaminants in background.
The particles collected on Stages E and D were embedded in the grease
layer. Because a SEM can only detect surface features, particle identi-
fication and sizing were, in many cases, not possible. Eventually,
measurement of Stage D was also done optically. However, the particle
sizes detected on Stage D (~2 jUm) border on the extreme limit of accu-
rate measurement by the available optical microscope.
The particle deposits were found to have agglomerates as shown in
Figures 17a and 17b. The agglomeration apparently takes place after
capture of the particles, because the agglomerates appear to be resus-
pended.
The silver membrane filters selected for temperature stability as
shown in Figures 18a and 18b did not have a smooth surface. Also,
the particle capture appeared to take place within the pores of the
matrix. Thus, qualitative evaluation was difficult.
Discussion
Inspection of the collected particles indicated that the first stages,
A to D, were collecting particles about 2 times the diameter predicted
by theory, while the last three stages performed as predicted. It is
suspected that the short sampling times caused severe flow transients
during the test which affected the collection efficiency. The significant
result of the particle inspection was that no evidence for particle re-
entrainment was discovered.
The large particles exhibited the typical spherical shape of fly ash
[MeCrone et al, 1972], while the particles on the filter had more
of an appearance of a floe. This may have been due to the agglomera-
tion of very small particles or the soluble particles indicated by the
trace element determinations.
71
-------
b)
75-285
-------
b)
Figure 18. Microphotograph of filter.
a) Outlet 0.47 Jim pore size
b) Inlet 0. 8 fj,m. pore size
75-286
73
-------
SECTION V
ENGINEERING ANALYSIS
INTRODUCTION
The objective of the engineering analysis was to assemble the
following information:
1. Capital costs
2. Operating costs
3. Major maintenance problems
4. Determine scrubber reliability
5. Estimate the cost required to minimize operating problems.
This section of the report will only be a summary of the findings
reported by Stearns-Roger in Appendix D.
CAPITAL COSTS
The total installed cost in 1972 for the scrubber was $4, 400, 000. Based
on the boiler nameplate rating of 150 raw, the cost is $29/kw or,
based on the rated gas volume (see Section I), is $4. 18/1000 m3 hr
($7. 10/1000 ACFM). The detailed cost itemization is given in
Table 1, Appendix D.
In 1975 dollars, the scrubber would cost $5,800,000.
OPERATING COSTS
The total operating costs are approximately $495, 000/year (fourth
quarter 1973 and the first three quarters of 1974} based on 75 percent
availability of the scrubber or 0.50 mills/kwh. The operating costs
are summarized in Table 3, Appendix D.
MAINTENANCE PROBLEMS
The scrubber had a number of maintenance problems, many of which
were solved during startup and operation. The problems mentioned
here are the more persistent ones which have defied solution. The
75
-------
maintenance problems are covered in detail in Appendix D. These
include:
1. Breakage of Mobile Bed Contactors
The plastic mobile bed contactors have been a chronic problem
from breakage from wear. The desired lifetime of the spheres
is one year, however, normally a lifetime of only 6000 hours
was experienced.
However, damage to the pump liners and plugging of the nozzles
can result from the fragments entering the liquor recycle pip-
ing. Screens in the scrubber hopper have eliminated this problem
with the penalty of adding screen cleaning to the required mainte-
nance. Public Service Company of Colorado has tested a number
of different packings and is currently using polyethylene spheres
in the scrubber.
2. Migration of Mobile Bed Contactors
The mobile bed contactors will also migrate from one section of
the scrubber to another if an opening the width of a contactor
exists in the partitions. Poor distribution of the contactors
causes channeling of flue gas and a reduction in particle collec-
tion efficiency.
3. Guillotine Dampers
The guillotine isolation dampers have caused problems due to
breakage of the damper when closing against a buildup of fly
ash and leakage.
4. Recirculation Pumps
The recirculation pumps have been a source of problems in the
past due to mechanical failure. A new pump has been tested by
Public Service Company of Colorado and has been providing
good service.
5. Reheater Section
The scrubbed gases are heated by direct contact with three banks
of steam coils. These coils are susceptible to pluggage and
corrosion in the wet flue gas scrubber discharge. Addition of a
second set of soot blowers and drying ash during periods of
76
-------
the scrubber shutdown with heavy soot blowing has had minimal
effect. Corrosion problems have rendered the heaters inoperable.
Both upper and lower layer reheat coils have been been removed.
6. Weather-related Problems
The freezing of lines has always been a problem during cold
weather. All lines must be heat traced and drained when the
scrubber is shut down.
Another solution is to enclose the scrubber in a weatherproof
building. The major problem with this is the possibility of
leakage of flue gas into the structure.
SCRUBBER RELIABILITY
The scrubber reliability followed a curve similar to other scrubber
operations at Public Service Company of Colorado. After an initial
drop in availability due to minor design problems, the availability has
been steadily increasing due to solution of many of the problems.
As of November 30, 1974, the scrubber had operated at 100 percent
of capacity 59. 9 percent of the time and at 80 percent of capacity or
greater 70. 9 percent of the time. The availability of the scrubber
is reported in T-15 and Figures 19 and 20 in Appendix D.
FEASIBILITY OF A "PROBLEM-FREE" SCRUBBER SYSTEM
The feasibility of using the design and operating experience to improve
availability of the scrubber was investigated. The goal was to
increase the availability of the scrubber, realizing that the main-
tenance required may slightly increase due to the extra equipment.
The suggested modifications are summarized below:
Estimated Availability
(Percent)
Identical Scrubber $5,800,000* 60-70
Extra 33-1/3 Capacity
Section 1,200,000 +10-15
Indirect Reheat,
Incremental 200,000
Scrubber Enclosure 90,000 + 5-10
Miscellaneous Charges 80,000
$7,370,000 85-95
1975 dollars
77
-------
The capital cost of $7, 370,000 is $49/kw for a 150 mw unit.
The important aspect of maintaining and improving the availability
of the scrubber system is the attitude of the plant operating and
maintenance people in keeping the unit on line.
The steadily increasing availability of the Cherokee scrubber is an
indication that the Public Service of Colorado is committed to solving
the operating and maintenance problems.
78
-------
SECTION VI
REFERENCES
Bird, A. N. , J. D. McCain, and D. B. Harris. Particulate Sizing
Techniques for Control Device Evaluation. 66th Annual Meeting of
the Air Pollution Control Assoc., Chicago, Illinois. Paper No.
73-282. June 1973.
Calvert, S. et al. Scrubber Handbook, Wet Scrubber System. Study.
Vol. 1, EPA PB-213-016, 1972.
Calvert, S. , N. C. Jhaveri, C. Yung. Fine Particle Scrubber
Performance. EPA-650/2-74-093. October 1974.
Calvert, S. Engineering Design of Fine Particle Scrubbers.
Jounral Air Pollution Control Assoc. , 24. p 929-934. 1974.
Camp, D. C., J. A. Cooper and J. R. Rhodes. Trace Element
Determination in Aerosol Particulate Samples: Intercomparison II".
X-Ray Spectrometry, _3, 47. 1974 .
Camp, D. C. , A. L. VanLehn, J. R. Rhodes, and A. H. Pradzynski.
Intercomparison of Trace Element Determinations in Simulated and
Real Air Particulate Samples. X-Ray Spectrometry, 4. p. 123. 1975.
Cohen, J. J. and D. M. Montan. Theoretical Considerations, Design,
and Evaluation of a Cascade Impactor. Am. Ind. Hyg. Ass. J. , 28,
pp. 95-104. 1967.
Dams, R. , K. A. Rahn and I. W. Winchester. Evaluation of Filter
Materials and Impaction Surfaces for Nondestructive Neutron Acti-
vation A.nalysis of Aerosols. Environ. Sci. Tech. _6. pp. 441-447.
1972.
Davidson, R. L., D. F. S. Natusch, and J. R. Wallace. Trace
Elements in Fly Ash. Environ. Sci. Technol. 13, pp. 1107-1113.
1974.
Ensor, D. S. , L. D. Sevan and G. Markowski. Application of
Nephelometry to the Monitoring of Air Pollution Sources, 67th Annual
Meeting of the Air Pollution Control Assoc. Denver, Colorado. Paper
No. 74-110, June 1974.
Ensor, D. S. and M. J. Pilat. Calculation of Smoke Plume Opacity
from Particulate Air Pollutant Properties. J. Air Poll. Control
Assoc., 21, pp. 496-501. 1971.
79
-------
REFERENCES (Continued)
Flocchini, R. G. , T. A. Cahill, D. J. Shadoani, S. Lange, R. A.
Eldred, P. J. Feeney, G. Wolfe, D. Simmeroth, and J. Suder.
Monitoring California's Aerosols by Size and Elemental Composition,
Part I: Analytical Techniques. Environ. Sci. Technol. In press.
Johnson, L. D. and R. M. Statnick. Measurement of Entrained
Liquid Levels in Effluent Gases from Scrubber Demisters. EPA
650/2-74-050. 13 pp. June 1974.
Junge, C. E. Air Chemistry and Radioactivity. Academic Press,
New York. pp. 157-159. 1963.
Lundgren, D. A. An Aerosol Sampler for Determination of Particle
Concentration as a Function of Size and Time. J. Air Poll. Cont.
Assoc. _17. 225 p. 1967.
Kaakinen, J. W. , R. M. Jorden, R. E. West. Trace Element Study
in a Pulverized-Coal-Fired Power Plant. University of Colorado,
67th Annual Meeting of the Air Pollution Control Assoc. , Denver,
Colorado. Paper No. 74-8. June 1974.
Marple, V. A. and B. Y. H. Liu. Characteristics of Laminar Jet
Impactors. Environ. Sci. Technol. J5. pp. 648-654. 1974.
McCrone, W. C. and J. G. Delly, The Particle Atlas, 2nd Ed. Ann
Arbor Science Pubs., Inc., Ann Arbor, Mich. 48106. 1973.
Pilat, M. J. , D. S. Ensor, and J. C. Bosch. Source Test Cascade
Impactor. Atmos. Environ,, 4. pp. 671-679. 1970.
Raben, I. A. Use of Scrubbers for Control of Emissions from Power
Boilers - U. S. Paper No. 13. Proceedings Symposium on Control of
Fine Particulate Emissions from Industrial Sources. San Francisco,
California. January 1974.
Ranz, W. E. and J. B. Wong. Impaction of Dust and Smoke Particles.
Ind. and Eng. Chem. , 44, 1371 p. 1952.
Rao, A. K. Sampling and Analysis of Atmospheric Aerosols. Particle
Technology Laboratory, Mechanical Technology Laboratory, University
of Minnesota. Publication 269. June 1975.
80
-------
REFERENCES (Continued)
Schlichting, H. Boundary Layer Theory. McGraw-Hill, New York.
742 p. 1968.
Sinclair, D. A Portable Diffusion Battery. Am. Inst. Hygiene Assoc.
J. pp. 729-734. 1972.
Smith, W. B., K. M. Gushing, and J. D. McCain. Particulate
Sizing Techniques for Control Device Evaluation. Special Summary
Report 21. 1974.
Smith, W. B. , K. M. Gushing, and G. E. Lacey. Andersen Filter
Substrate Weight Loss. EPA-650/2-75-022. 1975.
Sparks, L. E. Personal Communication. 1971.
Statnick, R. M. and D. C. Drehmel. Fine Particle Control Using
Sulfur Oxide Scrubbers. 67th Meeting of the Air Pollution Control
Assoc., Denver, Colorado. Paper No. 74-231. June 1974.
81
-------
APPENDIX A
WALL LOSSES IN INLET PIPING OF THE
PLANT PROCESS VISIOMETER
-------
WALL LOSSES IN INLET PIPING
OF THE PLANT PROCESS VISIOMETER
The most critical parameter affecting particle loss to flow piping
walls is the Reynolds number, defined as
where O = fluid density
"U = mean flow velocity
D = pipe diameter
jU = fluid viscosity
If this dimensionless parameter exceeds 2300 (Schlichting,
1968), there exists a high probability that turbulent flow will develop
if the pipe length is greater than 40 pipe diameters. This latter
figure represents the nominal distance required for the turbulence to
fully develop, and can be considered, for the purposes of this analysis,
to be a laminar flow region.
The mechanism of particle loss in (horizontal) laminar flows is
twofold: the particles will attain their terminal settling velocities
rather quickly and be deposited on the walls by simple sedimentation,
or be deposited on the walls by Brownian diffusion. The effects of the
former mechanism are most observable on large particles with high
inertia, while the latter mechanism is specific to small particles
whose diameter is on the same order as the gas mean free path.
Turbulent losses occur because of the combined effects of
Brownian and eddy diffusion. Eddy diffusion can be viewed as the
deposition of particles that are small enough to nearly "follow" the
random fluctuations of the turbulent flow, but if near the pipe wall
and projected at it, are deposited due to their own inertia. Small
particles (< 1 Aim) have insufficient inertia, large ones (> 50
will not respond to turbulent fluctuations.
A-l
-------
The PPV sampling probe, which can be as long as 3. 6 m (12 ft)
maintains flow velocities in the range of 15-21 mps. Assuming a local
altitude of 1. 5 km above sea level, so that (U. S. Standard Atmosphere
Tables, 1966)
p = ambient air density = 1.098 kg/m""
- e
X = ambient mean free path = 7. 68 x 10 m
a r
C = ambient sound speed = 344.4 m/sec
a
T = ambient temperature = 15°C
CL
and assuming Tf = gas temperature in the probe = 250 °F, the sampling
probe operates over a Reynold's number range of
8911 < R < 12,475
For the purposes of this calculation,
T
°£ = °f T
ft Tf3/2
where ft = 1.458 x 10"6 kg/(m-sec-(°K)1/s)
and S = Sutherland's correction = 110. 4°K
Thus, the PPV probe will be a mixture of laminar and turbulent
flow. In addition, the probe has a 3. 6 cm radius right-angle bend
This bend has the potential of generating pockets of turbulence (and
the associated deposition) on the inside wall of the turn. Further-
more, the centrifugal force experienced by particles in the fluid
stream will tend to deposit them on the outside wall of the turn by the
mechanism of impaction. Although not consistent with the probe's
actual geometry, the PPV flow piping was treated as a pipe of 40
diameters (0. 66 meters) of laminar flow, followed by a 3. 6 cm
radius turn, followed by a straight pipe between 0. 6 and 3 m in length,
A-2
-------
and in which fully developed turbulent flow had evolved. Presented
below are the details of the theories appearing in the literature that
were applied to this physical model.
A. 1 Laminar Sedimentation
Fuchs [1964] cites the result of G. Natanson for particle loss
due to simple sedimentation. The loss fraction due to sedimentation,
LF , is given by
s
LFg = 1 - \ (2 € Vl-C2/3 + arcsin (€1/3) - e1/3
3 V L
and where V = particle settling velocity
5
L = pipe length (0. 66 meters)
R = pipe radius
The settling velocity is normally given by
V = BF
s
where B = particle mobility
F - force on particle
The force on the particle in this case is gravity, so that
V = B (0,-^-O_) g ~7 d — B (0 ~T R d*1
s P f e 6 _ 6 6
where Pp = particle density =1.0 g/cc
g = acceleration of gravity
d = particle diameter
A-3
-------
The particle mobility, as suggested by Fuchs (1964) is given by
4.364 A, 2 A
for - »
1 + 0. 864
+ 0.29 — exp
B = <
3 TTJLl£d
2 A
for -r- « 1
d
where A = mean free path in the probe.
Since A is given by
A = 3
VTT M
8 RT
2 X,
for
where //, M, and R are the viscosity, molecular weight, and gas
constant, respectively, then
A. 2 Laminar Diffusion
Fuchs [1964] also specifies the losses to be expected from the
i of Brownian diffusion. The loss fracti
is a function of the dimensionless parameter
action of Brownian diffusion. The loss fraction due to diffusion, LF ,
r>
A-4
-------
4DL
77 =
where D = particle diffusion coefficient.
The exact relation has been empirically determined to be
"l - 0.819 exp (-3.65 77) -0.097 exp (-22.3 T?)
-0. 032 exp (-57 T?) for r\ > 0. 01
2.56 772/3 - 1.2 77 - 0.177 Ty4/3 for 17 > 0.01
The diffusion coefficient is given by
D = KTfB
where K = Boltzmann's constant
The particle mobility, B, is given by the equations listed in
the previous section.
Diffusion is naturally expected to show its greatest effect for
small particles. It should_be noted that, because the denominator of
77 contains the product of U D§>, as long as a constant flow rate and
laminar flow conditions are maintained, changing the tube size will
not vary the deposition rate.
A. 3 Losses at Piping Bends
Particle deposition at abrupt turns in the flow direction has been
studied in some detail due to its applicability in impactor work. The
dimensionless inertia parameter, J/>, referred to as the Stokes' number,
has been determined to govern inertia! impaction, where
V d2
* = 18M R
A-5
-------
where C = Cunningham slip correction factor
2X
= 1 + —- [1.23 + 0.41 exp (-0.44 d/X )]
According to Fuchs [1964], when the value of $ is less than 0. 05,
particles will follow flow streamlines and not be deposited. Assuming
the flow conditions described previously (U = 21 m/sec), the largest
particle that meets the Fuchs criterion is 5. 8 microns in diameter.
Ten micron particles yield a Stokes number of 0. 15. In impactor
work, the impaction efficiency has been determined to be a function
of V0. Stern et al [I960] performed experiments with impactors
having circular jets and determined the impaction efficiency as a
function of V$. Although not strictly applicable in this case, the
Stern curve has been used to estimate the loss of 10 micron particles.
The result indicates that roughly 70 percent of all 10 micron particles
would be impacted on the pipe wall at the right angle turn. This figure
has been for the loss fraction due to the probe bend of radius R,
Reiterating, LF for all particles of diameter d < 5.8 pm is equal
to zero.
A. 4 Turbulent Deposition
Turbulent losses are the result of a combination of Brownian
and eddy diffusion, and are not completely understood. Several
theories exist in the literature, however, and are compared to experi-
mental results in a paper by Liu and Agarwal [1974]. They indicate
that the theories of Friedlander and Johnstone [1957] , Beal [1970]
and Liu and Ilori [1973] describe the mechanism quite accurately in
the larger particle ranges (^ 1 Urn), but fail to varying degrees in the
range where Brownian diffusion begins dominating deposition. The
theory of Da vies [1966], on the other hand, underestimates the rate of
deposition in the large particle range, and overestimates slightly in
the Brownian diffusion regime.
Parker [1968] relates the loss fraction equation common to all
theories as
= 1 - exp I - -=
A-6
-------
where LF = loss fraction due to turbulent deposition
and v = transport or deposition velocity
The goal of all of the above mentioned theories is to evaluate v^.
All theories deal with the stopping distance of the particles of
interest. It is assumed that the turbulent fluctuations hurl the par-
ticles at the wall boundary layers at a velocity proportional to the
mean velocity, and only those particles brought to within one particle
stopping distance will be deposited. The essential differences in the
theories are to be found in the constant of proportionality between the
"hurling" velocity and the mean velocity, and in the form of the
empirical relations for the eddy diffusion coefficients that are required
for the analysis.
The authors have selected a combination of the theories of
Davies and Beal for deposition calculations. Specifically, the theory
of Davies was used in the calculation of 0. 01 and 0. 1 Jim deposition,
while all other particle sizes were subjected to the Beal theory. The
essentials of these theories are now presented.
A.4.1 Small Particle Turbulent Deposition [Davies, 1966]
All variables are first non-dimensionalized in the standard fluid
mechanical fashion
where y = distance from the pipe wall
U - friction velocity of turbulent flow
#
V = kinematic viscosity
For the purposes of these calculations, the Blasius value of
is used:
A-7
-------
0.3164 -
Y' defines the non-dimensional thickness of the Brownian
diffusion layer and is given by
i
Y+ - 20(D/v)
i/a
T is the non-dimensional relaxation time, given by
ru?
where T is the relaxation time. Here,
T = Bm
where m is the particle mass.
If a i = —, where d, is the dimensionless particle diameter,
the non-dimensional radial fluctuation velocity is given by
a++10\ /, / a, + 10*2
V'' = 2 I1 " ~~r. I ' \l 4 \- T, I ' T +
The non-dimensional particle stopping distance is given by
A-8
-------
The value of $ is next calculated from
$ =
S+ + a-f
10 (D/v)1/3
The non-dimensional deposition velocity is then given by
10
(*)
2/3
R+
Wy, +
R
for
for s+ -f a+ > y'+
In these equations,
1 +
1 . 2 $ -1
— arctan —
R.
and [I] =
y +
c/v
(4 - 0.08 y+)
where C/V
10001—-
and e = eddy diffusion coefficient
R = non-dimensional pipe radius
The above integral has been evaluated by computer and is tabulated
in the paper by Davies.
A-9
-------
A. 4.2 Large Particle Turbulent Deposition fBeal, 1970]
Beal estimates the particle stopping distance, S, to be given by
d2 V
S =
18 ju
where
V = 0.9 U,
The average velocity, V, of particles close to the pipe wall is
considered to be composed of two components: that due to the fluid
motion (V ) and that due to Brownian diffusion (V ). Hence,
f B
V = V
Beal defines a transport coefficient, K, and this parameter is
related to the deposition velocity by the equation
V - KVP-
t K+PV
where P is the sticking probability, assumed to be 1.0 for this analysis.
The particle velocity due to fluid motion is taken from the data of
Laufer (1951) and is given in non-dimensional form as
0.05 y , 0 ^ y £ 10
0. 5 y+ + 0.0125 (y - 10), 10 s y <: 30
Since the particles may be anywhere between y+ = S+ and
y-f = d+/2, Beal averages the values of VJ" at these locations in a
special fashion to obtain
v =
v fc] + V*(s}]
\\2>+ v£ vs+yj
A-10
-------
Vj3 is given by the equipartition energy formula from the kinetic
theory of gases
v ,\^r
B L 2TTm J
The value of K depends upon the magnitude of S :
K
U,
1.5 R
- O.,5,v
U *
250
R.
1 + -~- (D - 0.959 v)
VR+
D + 5.04 v
D + vl~ - 0.959)
U - 13.73
U
r-
for 5 ^ S+ < 30
U.
U - 13.73 U
, for S , > 30
A-ll
-------
If A is defined as
A =
5 / v \ ^ *" ' * \" / M \ 2/3
1- TTs ID) +\i4.
5 \2/vV
^) (D)
and B =
14
C =
-------
REFERENCES
Beal, S. K. , 1970: Deposition of particles in turbulent flow on
channel or pipe walls. Nucl. Sci. and Eng. , 40, 1-11.
Davies, C. N. , 1966: Deposition of aerosols from turbulent flow
through pipes. Proc. Roy. Soc. , A, 289, 235-246.
, 1966: Brownian deposition of aerosol particles from
turbulent flow through pipes. Proc. Roy. Soc., A, 290, 557-562.
Friedlander, S. K. , and H. F. Johnstone, 1957: Deposition of
suspended particles from turbulent gas streams. Ind. Eng.
Chem. , 49, 1151-1156.
Fuchs, N. A., 1964: The Mechanics of Aerosols. New York,
MacMillan Co. , 408 pp.
Liu, B. Y. H. , and T. A. Ilori, 1973: Inertial deposition of
aerosol particles in turbulent pipe flow. American Society
of Mechanical Engineers Symposium on Flow Studies in Air
and Water Pollution, Atlanta, June 20-22, pp. 103-113.
Liu, B. Y. H. , and J. K. Agarwal, 1974: Experimental observation
of aerosol deposition in turbulent flow. Aerosol Sci. , 5_,
145-155.
Parker, G. J. , 1968: Some factors governing the design of probes
for sampling in particle - and drop - laden streams.
Atmos. Envir . , 2_, 477-490.
Schlichting, H. , 1968: Boundary Layer Theory. New York,
McGraw-Hill, 742 pp.
Stern, S. C. , H. W. Zeller, and A. I. Schekman, 1962:
Collection efficiency of jet impactors at reduced pressures.
I & EC Fundamentals, pp. 1, 1962.
U. S. Standard Atmosphere, 1962.
A-13
-------
APPENDIX B
REDUCED DIFFUSION BATTERY AND IMPACTOR DATA
-------
Table B-l
CASCADE IMPACTOR TESTS USED IN PENETRATION
ANALYSIS
MONTH DAY RUN#
November 20 53
55
56
57
21 60
61
December 10 109
110
113
114
116
118
119
120
122
11 123
124
125
126
127
12 129
130
131
132
133
134
135
136
LOCATION
Outlet
Inlet
Inlet
Outlet
Inlet
Outlet
Outlet
Outlet
Inlet
Inlet j
Outlet
Outlet
Inlet
Inlet
Outlet
Inlet
Inlet
Outlet
Outlet
Inlet
Outlet
Outlet
Outlet
Outlet
Inlet
Inlet
Inlet
Inlet
B-l
-------
Wall
0.5
1.0
H
U
W
Q
1.5
2.0_
Wall
Wall
Inlet
D Duct II 127°C
» Duct B 71° C
o Ducr C 71° C
10 15 20
VELOCITY, m/sec, STACK CONDITIONS
25
75-238
Fig. B-l. VELOCITY TRAVERSE INLET AND
OUTLET DUCTS (NOVEMBER 20, 19741
B-2
-------
Wall
0.5
£ i.o
U
P
Q
ffi
H
&
W
Q
1.5
2.0
Wall
Wall
Inlet
D Duct.il
132° C
a Duct n
O Duct <>
71° C
71° C
_L
1
10 15 20
VELOCITY, m/sec, STACK CONDITIONS
I
25
Fig. B-2. VELOCITY TRAVERSE INLET AND OUTLET
DUCTS (NOVEMBER 21, 1974)
B-3
-------
Wall
0.5
1.0
H
U
W
Q
i c
2.0
D Duct A
X Duct B
o Duct C
Wall
Wall
D Duct II 132° C
74° C
68° C
68° C
_L
J.
10 15 20
VELOCITY, m/sec, STACK CONDITIONS
25
Fig. B-3. VELOCITY TRAVERSE INLET-AND OUTLET
DUCTS (DECEMBER 10, 1974)
B-4
-------
Wall
0.5 _
1.0
H
O
P
Q
ffi
fc
W
Q
1.5
2.0
Wall
0 Duct II 127° C
H Duct in 127 °C
D Duct A
* Duct F
O Duct C
77° C
66° C
66° C
Wall
4-
j i
10 15 20
VELOCITY, m/sec, STACK CONDITIONS
25
75-242
Fig. B-3. VELOCITY TRAVERSE INLET AND OUTLET
DUCTS (DECEMBER 11, 1974)
B-5
-------
Wall
0.5 _
fi 1.0
H
U
P
Z
W
Q
2.0
Inlet
D Duct II
D Duct A
« Duct B
° Duct C
Wall
-L
_L
Wall
127° C
77° C
68° C
71° C
10 15 20
VELOCITY, m/sec, STACK CONDITIONS
25
75-243
Fig. B-4. VELOCITY TRAVERSE INLET AND OUTLET
DUCTS (DECEMBER 12, 1974)
B-6
-------
Table B-2
STAGE
NUMBER
1
2
3
4
5
6
7
Filter
DATA FOR RUN 56, INLET
CUT DIAMETER
MICRONS
35
17
6.8
2.6
1.6
0.66
0.39
CUM. MASS
CONC . , MG/DSm3
426
424
404
335
158
109
87.6
87.6
I WEIGHT
-------
Table B-4 DATA FOR RUN 55, INLET
STAGE
NUMBER
1
2 1
CUT DIAMETER
MICRONS
35
18
3 6-5
4
5
6
7
Filter
i
3.2
1.6
0.64
0.54
CUM. MASS
CONG., MG/DSm3
493
456
434
291
132
61.5
49.0
42.1
% WEIGHT
-------
Table B-6 DATA FOR RUN 60, INLET
STAGE
NUMBER
1
2
3
4
5
6
7
Filter
CUT DIAMETER
MICRONS
33
16
6.1
3.0
1.5
0.59
0.50
CUM. MASS
CONG . , MG/DSm
489
435
410
265
113
45.0
24.6
17.3
% WEIGHT
-------
Table B-8 DATA FOR RUN 114, INLET
STAGE
NUMBER
1
2
3
4
5
6
7
Filter
CUT DIAMETER
MICRONS
29
15
5.3
2.5
1.6
0.69
0.27
CUM. MASS
CONG. , MG/DSm3
1820
1010
745
384
129
43.7
25.9
16.2
% WEIGHT
-------
Table B-10
STAGF.
NUMBER
1
2
3
4
5
6
7
Filter
. DATA FOR RUN 113, INLET
CUT DIAMETER
MICRONS
32
16
6.2
2.5
1.5
0.66
0.28
CUM. MASS
CONG . , MG/DSm3
4650
2330
1670
1010
380
111
63.1
54.2
% WEIGHT
-------
Table B-12. DATA FOR RUN 119, INLET
STAGE
NUMBER
1
2
3
4
5
6
7
Filter
CUT DIAMETER
MICRONS
33
17
6.4
2.5
1.5
0.68
0.29
CUM. MASS
CONG., MG/DSm3
541
429
417
344
164
116
84.0
73.3
I WEIGHT
-------
Table B-14. DATA FOR RUN 120, INLET
STAGE
NUMBER
1
2
3
4
5
6
7
Filter
CUT DIAMETER
MICRONS
31
16
5.8
2.7
1.7
0.76
0.31
CUM. MASS
CONG . , MG/DSm3
414
392
378
300
125
63.7
41.2
31.8
% WEIGHT
< CUT DIAMETER
100
94.6
91.3
72.3
30.3
15.4
10.0
7.7
Table B-15. DATA FOR RUN 118, OUTLET
STAGE
NUMBER
1
2
3
4
5
6
7
Filter
CUT DIAMETER
MICRONS
21
10
4.0
1.5
0.90
0.37
0.20
CUM. MASS
CONG . , MG/DSm3
54.1
52.5
49.3
49.3
45.9 .
40.1
34.5
32.2
I WEIGHT
-------
Table B-16. DATA FOR RUN 123, INLET
STAGE
NUMBER
1
2
3
4
5
6
7
Filter
CUT DIAMETER
MICRONS
35
17
6.7
2.7
1.6
0.72
0.31
CUM. MASS
CONG . , MG/DSm3
1160
904
859
585
187
70.0
41.9
33.8
I WEIGHT
-------
Table B-18. DATA FOR RUN 124, INLET
STAGE
NUMBER
1
2
3
4
5
6
7
Filter
CUT DIAMETER
MICRONS
34
17
6.4
3.0
1.8
0.84
0.34
CUM. MASS
CONC . , MG/DSm3
1300
1070
1010
556
185
62.7
35.2
20.4
% WEIGHT
-------
Table B-20. DATA FOR RUN 127, INLET
STAGE
NUMBER
1
2
3
4
5
6
7
Filter
CUT DIAMETER
MICRONS
36
18
7.1
2.8
1.7
0.76
0.33
CUM. MASS
CONG . , MG/DSm3
2730
1500
1080
664
246
124
84.4
52.0
I WEIGHT
-------
Table B-22. DATA FOR RUN 133, INLET
STAGE
NUMBER
1
2
3
4
5
6
7
Filter
CUT DIAMETER
MICRONS
34
17
6.3
3.0
1.8
0.82
0.34
CUM. MASS
CONG . , MG/DSm3
866
712
677
449
155
34.1
18.7
18.7
% WEIGHT
-------
Table B-24. DATA FOR RUN 134, INLET
STAGE
NUMBER
1
2
3
4
5
6
7
Filter
CUT DIAMETER
MICRONS
35
18
6.8
2.7
1.6
0.73
0.32
CUM. MASS
CONG., MG/DSm3
1070
850
775
467
126
22.5
16.8
16.4
% WEIGHT
-------
Table B-26. DATA FOR RUN 135, INLET
STAGE
NUMBER
1
2
3
4
5
6
7
Filter
CUT DIAMETER
MICRONS
35
18
6.8
2.7
1.6
0.74
0.32
CUM. MASS
CONG . , MG/DSm3
1440
1070
956
526
173
58.1
30.1
25.4
% WEIGHT
-------
Table B-28. DATA FOR RUN 136, INLET
STAGE
NUMBER
1
2
3
4
5
6
7
Filter
CUT DIAMETER
MICRONS
34
17
6.4
3.0
1.8
0.84
0.34
CUM. MASS
CONG . , MG/DSm3
1360
1010
901
543
175
51.6
22.8
18.7
% WEIGHT
-------
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Figure B-5: Size distributions from cascade impactor
tests
B-21
-------
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OUTLET, RUN #61
•
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5 10 20 30 40 50 60 70 80 90 95 98
PERCENT BY WEIGHT UNDERSIZE, %
Figure B-6 Size distribution from cascade impactor
tests
8-22
-------
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116
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1
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PERCENT BY WEIGHT UNDERSIZE, %
Figure B-7 Size distributions from cascade impactor
tests
B-23
-------
9. 0
8 0
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3.0
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PERCENT BY WEIGHT UNDERSIZE, %
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Figure B-8: Size distributions from cascade impactor
tests
B-24
-------
10
5 1
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PERCENT BY WEIGHT UNDERSIZE, I
Figure B-9: Size distributions for cascade impactor
tests
B-25
-------
10
w
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Figure B-10: Size distributions for cascade impactor
tests
.26
-------
350
300
n
CO
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PARTICLE DIAMETER, ym
Figure B-ll:
Cumulative mass distribution from
cascade impactor tests
B-27
-------
n
bo
E
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t—(
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W
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2:
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A OUTLET, RUN #57
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Figure B-12:
468
PARTICLE DIAMETER, ym
Cumulative mass distribution from
cascade impactor tests
•
B-28
10.
-------
350
300
"s
w
Q '
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6
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M
200 i
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1 . 1 1
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ET CUMULATIV
:
2468
PARTICLE DIAMETER, ym
Figure B-13: Cumulative mass distribution from
cascade impactor tests
10
B-29
-------
140U
1
i
200
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ra
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Figure B-14:
PARTICLE DIAMETER, pm
Cumulative mass distribution from
cascade imoactor tests
B-30
-------
700
600 —-
500
400
100
300 ! ;,
200 i
246
PARTICLE DIAMETER,
Figure B-15: Cumulative mass distribution from
cascade impactor tests
-
-
-
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w
CJ
c
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-------
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70
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en
30
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0
2 4 6 8 10
PARTICLE DIAMETER, pm
Figure B-16: Cumulative mass distribution from
cascade impactor tests
Q
;
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B-32
-------
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7 n n
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n
E
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6
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70
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Figure B-17:
PARTICLE DIAMETER, ym
Cumulative mass distribution from
cascade impactor tests
B-33
-------
/uu
600
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CO
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w>
S r nn
OU \J
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0
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Cumulative mass distribution from
10
Figure B-18: Cumulative mass distribu
cascade impactor tests
B-34
-------
700
600
n
d
C
s
bo
6
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Z
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g
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120
a
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100
80
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40
100 5-
INLET, RUN #124
20
JL
A
I
OUTLET, RUM #125 :
246
PARTICLE DIAMETER, pm
10
:
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Figure B-20:
Cumulative mass distribution from
cascade impactor tests
B-35
-------
INLET CUMULATIVE MASS CONCENTRATION, mg/DSm
M |X» W *• %
g g g g g 1 g
I
1 i r-^U
0
*
*
•
s
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> — '
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.
1 i _L
0 4 6 8 10
g g s s s s
OUTLET CUMULATIVE MASS CONCENTRATION, mg/DSm3
Figure B-21:
PARTICLE DIAMETER, ym
Cumulative mass distribution from
cascade impactor tests
B-36
-------
700
n
1
Q
INLET CUMULATIVE MASS CONCENTRATION, mg
M ro w £
ooo o c
o o _____S - . ?
' 1 j
•
•
• • . i - • J ••••;•". • ' ' ' i I 1 '.!'.-
• i ;r::; :. i. , .;;.r::;:
.1
.. ,. . .;: :. . .-;[:: .. ;:.: t;: ! . . j
' ... - . ., , i. .-,---. , . . -4 , -—
-- ----- - - -- j ' -- •• • -: ••- :
t ' - 1 - - • • i
'
f ^Tt
A ...
^^-^~~:~~~ ' •' •• '^
-------
ra
E
:
^;
•.
700
Ann
O UU
c n n
oUU
Ann
4U U
"son
?nn
100
' 1 *
: . .'•'::'•• : ;;- ' :^
-----
'
i
i
,-,
* ' * /
! : .:,-;./ • : . :
/
^' ' '
i /A -~
C
("^INLET, RUN #133 i
^— '
A OUTLET, RUN #129
GL — *
i
.
0°' « »
14U
n
120 g
w
^
bO
e
100 o
i — i
i
f-i
w
ft n o
o u QJ
C/D
60 f_ ,
i
u
t-
>i n W
4U j
0
20
0
468
PARTICLE DIAMETER, ym
10
Figure B-23: Cumulative mass distribution from
cascade impactor tests
B-38
-------
700
600
S
Q
wS 0 0
2
O
t— i
H400
|
0
CJ
co
00
<300
«*.
u
^>
—
s
_J
2 200
;=>
w
-
2:
—
100
Q
I ~T F
••]
..;{._ . .._,_ ;. ^ ;---:.-. -: ..--..: -,--—-
.: '.-;. - • :* _^ ^M iii^ij • i il
/
/ (^
f^/ ; . : .;> / ; : :| ;!?i:;!^:
:..._jt: --,/ i; :--;-;
r ' , I . , - -
/ - . '* -J
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' / : ••! "' /. ::;:: :
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/ ; .• :
I - - i ~ -
i'\
• . . •
r i • - - -
! 0
/
O INLET, RUN #135 1
rS"" /\
,W. ^OUTLET, RUN #132'
L! i • I
'
6n
CO
Q
en bO
g
**
h-l
40 £
w
u
0
u
oo
00
•in $
OU S
, |
20 §
H
w
•-J
s
o
10
0
2468
PARTICLE DIMETER, ym
Figure-B-24: Cumulative mass distribution from
cascade impactor tests
B-39
-------
to
I
,0
TIO
LET CUMULATIVli MASS CONCENT
you
600
500
400
300
200
100
-T- -r
.
; . - •
.
^ — """ • \
hs-
/
t
s
A 0^
/^
: / •_._........
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vi/
. .
L-
f^INLET, RUN #136
AOUTLET, RUN #131
C '-vl/ ^
• i
L40
120
1
s
bO
100
6
i— i
H
H
80 g
u
0
LJ
to
co
<
^r r\ f^>
w
>
i — i
H
<
nJ
2
40 g
E-
W
J
H
^
O
20
1
•
-10
0 2 4 6 8 10
PARTICLE DIAMETER, ym
Figure B-25: Cumulative mass distribution from
cascade impactor tests
B-40
-------
--
:
•
_
.-.
.--
•
.--
--
w
::
P3
0
.,.
--
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0.05
0.01
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: I -• - i : r: :^:;r^l:::::~E7=:==rirL;£:::{^::t^-^^
1 Hj
f::-^:>£4-:^,-.-33
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ORUNS #56 PI #53 -h-i iLt' " i ' "• -':'T;.:;.. ';;';:.! '..Ti!l=
/\RUNS #55 § 57
i.. ; .1 .... - .
r- -i •" - : -. \ i r ±i-
0. 1.0 2345 1
0
PARTICLE DIAMETER, ym
Figure B-26: Particle penetrations for cascade
impactor tests
B-41
-------
1.0
z 0.5
o
E-i
U
SI 0.3
* no
2 0.2-
O
H
<^
f-V?
£_C
w
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a,
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dt
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0.1 1.0 10
PARTICLE DIAMETER, pm
Figure B-27: Particle penetrations for cascade
impactor tests #60 5 "'"•
B-42
-------
• -
:-
-
:
-
w
^
^
--
:
-"
1.0
0.5
0 .4 __-
0.3^
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0.05!
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:
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pjiz
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T----T- ;!.^;r -•- t^ -.,.:;::::.r;-; ;-:;:i ^ ;
- - i - - • • J -- - - - -
) Runs 110 ^ 113
X^Runs 109 ^ 114
Runs 116 5 119
• , .
>Runs 120 $ 118
—••--••••
•
1 • :
i I' I :r; [_\ i i . ..
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i
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f I i I ±±±±
0.1
0.5 1.0 2
PARTICLE DIAMETER, ym
345
10
Figure B-28: Particle penetrations for cascade
impactor tests
B-43
-------
1.0-
:
•-
—
c.
...
••
•.-•
:
•—
—
___
w
'":
P
w
.
....._. j_... t-^fl^t —\—!
'TL'r* '—~ j1*- ~~~,~ ". '*" .. , "T^^ ~ \
Runs 129 § 133
Runs 132 S 135
Runs 130 § 134 ,
^ Runs 131 S 136 .'"
I
. .
0.011
0.5 1.0 2345
PARTICLE DIAMETER, pm
Figure B-29: Particle penetrations for cascade
impactor tests
B-44
-------
:-.
C
—
:-
U
2
Z
:
—
-
2
-
-
z
H
-
-
-
_
—
-
-
fS
o
O
0.01
— \7Ruris 122 § 123"
_ £>Runs 124 § 125;.;..._
(ft Runs 127 & 126
i •-•- i i s i 'i
!
0.1
0.5 1.0 2345
PARTICLE DIAMETER, ym
10
Figure B-30: Particle penetrations for cascade
impactor tests
B-45
-------
Table B-30. RUNS TAKEN WITH DIFFUSION BATTERY
DATE
11/21/74
11/21/74
11/21/74
12/9/74
12/9/74
12/10/74
12/10/74
12/10/74
12/10/74
12/10/74
12/10/74
12/10/74
12/10/74
12/10/74
12/10/74
RUN #
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
START
TIME
09.40
12:15
14:10
08:55
13:05
15:35
10:00
12:24
16:28
11:08
12:51
16:24
09:19
14:23
15:29
FINISH
TIME
10:45
13:25
15:00
10:40
14:10
16:08
10:20
13:19
16:58
12:01
13:39
16:59
10:27
14:48
16:09
LOCATION
Inlet
Inlet
Inlet
Inlet
Inlet
Inlet
Inlet
Inlet
Outlet
Outlet
Outlet
Inlet
Inlet
Outlet
Outlet
B-46
-------
Table B-31. DIFFUSION BATTERY TESTS WITH COMPARABLE CASCADE
IMPACTOR TESTS
INLET
OR
OUTLET
Inlet
Outlet
Outlet
Inlet
Inlet
Outlet
IMPACTOR
RUN
#
120
118
122
123
133
129
S.D.B.
RUN
#
8
9
10
12
13
15
B-47
-------
Table B-32. DIFFUSION BATTERY NUMBER MEDIAN DIAMETERS
AND STANDARD DEVIATIONS
D.B.
RUNS
8^9
10512
13615
INLET OUTLET
dpn,*ym
0.071
0.094
0.18
°g
1.5
1.4
3.6
dpn,*ym
0.11
0.051
0.063
og
22.0
3.3
1.9
* d refers to number median diameter
pn
B-48
-------
dd
i
a
• o
0.3
0.02
0.01 0.1
5 10 20 30 40 50 60 70 80 90 95
NUMBER PERCENT UNDJERSIZE
99
Figure B-31 Size distribution for Run #8 inlet by Screen Diffusion Battery
-------
. :
^
-
-
- -
C
-
.
i:*j
- .
- .. ; fr^i
'
r •
_
-
0.01
5 10 20 30 40 50 60 70 80 90
NUMBER PERCENT UNDERSIZE
Figure B-32:
Size distribution for Run #9 outlet
by Screen Diffusion Battery
B-50
-------
.
-
...
—
"-.
-----
0.10
0.07
0.05
0.03
0.02
0.01
•!•• ryt: :
. i:.. . . i ::•.: h... L
— , — ; - ; — — !- -
•"-'L
'."' *—' '.-.£-
bEEfe
' '
10 20 30 40 50 60 70 80 90 95
NUMBER PERCENT UNDERSIZE
Figure B-33— Size distribution diffusion battery
Run #10, outlet
B-51
-------
0..5U
Ot n
. ZU
g
31
c*r
w
S 010
i — i
Q
n n7
PI u . u /
u
1— (
t-
c±l n n c
PS 0.05
(X
0 04
0 .03
2
1
: L __^-.
-
-
•
•
.
:
•
"- : - J
--^^
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1
5 :
r
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•
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; - -
. 1
: ~ .t~ .-^-_
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: • . . .: !
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1 I
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—
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r
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:
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p \ ;
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^^
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,
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1
10 50 6
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0 7
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t -----
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9
1 : j
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j
:
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-
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0 95 9
.
--- - •
i
-
. _
:--.-
r-_L
itrrfr:
j r
: '_'
8 9
NUMBER PERCENT UNDERSIZE
Figure B-34 - Size distribution diffusion battery
Run #12, inlet
B-52
-------
LI
W
<
•—
n
—
•—i
—
—
0.5
0.3
0.2
0.1
0.07
0.04
0 .02
0.01
10 20 30 40 50 60 70
NUMBER PERCENT UNDERSIZE
Figure B-35- Size distribution, diffusion battery
Run #13 inlet
B-53
-------
ym
.-
-
-
.--
-
—
E-
d,
0.3
0.2
0
•
o
.
o
o
.
o
4=»
o
o
KJ
o
o
1
•
t
• - 1
•
1
•
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'. ~ '--
o
X
s
i -
- |
i
I
5
:
• •
:
.
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t ...-_
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X
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•
•
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6
.
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1
1
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i
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t
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•
0 50 6
; i T
L
I;. 1 ;
/
/
/ —
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f
~\ ^1
C-'
y\
^
.1 — . —
r . ,.
' - '
..,:- !•- '• •' - '
• ^m • • --\ ,
--.----; ' '-- ' :
-•- - -•--'•-•- : - -- - •
'- !• . •- . : :
= —
I ^ : :r:
L -_— • . ' ' - : - - : ±
;;-.-. j- .-.'I--'
EETT .. - i • ':
i
! ..-..- i ^
1 i '
!
• i :
1 II
0 70 80 90 95 9!
NUMBER PERCENT UNDERSIZE
Figure B-36- Size distribution for diffusion battery
Run #15, outlet
B-54
-------
INLET, RUN #8
OUTLET., RUN #9
0 0.05
Figure B-37-
0.10
0.15
0.20
0.25
0.30
Cumulative mass distribution, diffusion battery
Runs #8 $ #9
B-55
-------
I
0
-
-
w
c.
r-
"
P-3
0.05 0.10 0.15
PARTICLE DIAMETER, ]
0.20
0.25
Figure B-38:
Cumulative mass distribution, diffusion
battery, runs #10 § #12 t
B-56
-------
fl
'r\
6
~
U
,'
c
c_
•J-.
>
—
—
0.60
40
2
p
c
M
-
-<
P-
H
2
W
C
L.
20
p
2
.-
w
—
0.05
Figure B-39:
0.10 0.15 0.20 0.25
PARTICLE DIAMETER, ym
0.30
Cumulative mass distribution, diffusion
battery, runs #13 § #15
B-57
-------
APPENDIX C
REDUCED ELEMENTAL CONCENTRATION DATA
-------
Run No. 109 Location Outlet B
(Concentration, micrograms /DSm3 )
3 a 12/10 1110 MST
Stage A.-§.CjD_EJL.G.H
D50 28.6 14.4 5.28 2.49 1.51 0.69 0.28
Elements
37.2 37.0 8.8 22.6
64.3 60.6 20.2 83.1
2.3 3.2* 2.8* 595.0
3.0* 3.2* 2.9* 9.0*
5.2 3.6 1.1 7.0
36.4 33.7 15.5 345.4
5.6 5.9 2.6 36.4
1.7* 1.9* 1.6* 5.7*
1.5* 1.6* 1.4* 22.4
0.4
34.2 27.8 12.8 383.7
1.5* 1.6* 1.4* 7.6
1.4 1.2 0.7 672.4
1.8* 2.0* 1.8* 442.6
0.3
2.6* 2.6* 2.6* 5.7*
0.6
Al
Si
S
Cl
K
Ca
Ti
V
Cr
Mn
Fe
Co
Ni
Cu
Zn
As
Se
Br
Rb
Sr
Zr
Ba
Pt
Au
Hg
Pb
4. 6*
3.5
3. 4*
3. 6*
2.2
4.4
1 . 4*
3.7
1.1*
-
1.0*
_
0. 9*
0.8
1.1*
-
-
1.6*
-
-
-
_
-
-
-
3. 2*
5.6
14.8
3. 6*
3. 9*
2. 3*
5.1
1.7*
1.7*
1.5*
-
1.3
-
1.5*
1 . 1 *
1.8*
-
-
2.7*
-
-
-
_
-
-
-
5. 7*
24.4
37.5
2. 9*
3.0*
2.4
16.9
2.4
1.6*
1.4*
-
15.8
-
1.4*
1.0
1.7*
-
-
2. 4*
-
-
-
-
-
-
-
4.7*
12.8
18.0
2. 7*
2. 9*
2.5
10.6
1.5
1. 5*
1. 3*
-
7.9
-
1. 3*
0.7
1.6*
-
-
2. 3*
-
-
-
-
-
-
-
2.8
5.0* 5.1* 5.1* 90.2
Concentration below reported detectable limit
Not detected
Dry standard 21. 1° C, 760 mm Hg
C-l
-------
Run No. 110 Location Outlet A
(Concentration,
Stage
D5o
A
28.99
3 a
micrograms /DSm )
_B
14.5
C.
5.34
D
2.5
E
1.51
12/10 1142 MST
_F
0.69
G
0.27
H
Elements
Al
Si
S
Cl
K
Ca
Ti
V
Cr
Mn
Fe
Co
Ni
Cu
Zn
As
Se
Br
Rb
Sr
Zr
Ag
Ba
Pt
Au
Hg
Pb
8.4
17.2
7. 2*
7.8*
4.3
8.2
2. 9*
2. 8*
2. 4*
16.3
_
2.0*
1.4
2.5*
_
„
3. 9*
_
—
_
_
—
_
_
_
7. 8*
10.7*
17.1
8. 2*
8.9*
3.7
9.4
5.1
3. 8*
3. 4*
_
7.8
_
3.3*
2. 5*
4. 1*
_
_
6.0*
_
_
_
_
_
_
_
_
12.6*
5.1
10.4
5.2*
5.5*
2.4
8.9
2. 9*
2.9*
2. 5*
—
2. 5*
_
2. 5*
1.4
3. 1*
_
_
5. 7*
_
_
_
_
-
_
_
_
11.3*
57.7
100.6
6. 5*
6. 9*
7.7
58.0
7.7
3. 6=:=
3. 2*
_
72.7
_
3.2*
2.1
3. 8*
_
_
6.2*
_
_
_
-
_
_
_
_
12.5*
94.3
173.0
7. 1*
7. 2*
6.9
101.7
14.8
4. 2*
3. 6*
_
96.3
_
3. 6*
3.6
4. 4*
_
_
6. 0*
_
-
_
-
-
_
_
0.2
11.8*
117.8
212.4
8.8
6. 8*
10.2
142.2
21.9
4.0
3. 4*
120.0
_
3.4*
3.0
4. I*
_
_
5. 5*
_
0.4
-
-
-
-
_
0.3
10.9*
61.2
135. 0
61.9
7. 5*
3.3
43.1
19.5
8.6
3.8*
0. 1
100. 1
-
3.9*
6.9
19.1
-
_
5. 4*
-
-
-
-
-
-
_
-
10.7*
171.0
333.2
2302. 1
19.7-
27. 5
279.9
12. 3;
12. 5:
145.9
0. 6
1736.6
_
87.2
906. 9
738.0
-
0.2
9. 8'-
0. 3
1. 1
-
-
2.7
-
-
-
28. 4
Concentration below reported detectable limit
Not detected
Dry Standard 21. 1° C, 760 mm Hg
C-2
-------
Run No.
Ill
(Concentration,
Stage
D5o
A
29.0
micrograms /D
_B
14.5
_C
5.37
Elements
Al
Si
S
Cl
K
Ca
Ti
V
Cr
Mn
Fe
Co
Ni
Cu
Zn
As
Se
Br
Rb
Sr
Zr
Ag
Ba
Pt
Au
Hg
Pb
7.7
12.6
3.5*
2. 1
2.0*
6.5
1.4*
1.5
1.1*
-
2.9
-
1.0*
0.5
1.2*
-
-
1.7*
-
-
-
-
-
-
-
-
3. 3*
17.4
29.9
3. 8*
4.2*
2.8
11. 0
2.3
1.8*
1.6*
-
11.2
-
1.6*
1.0
1.9*
-
-
2. 5*
-
-
-
-
-
-
-
-
5.4*
42.8
73.5
3.1
3.8*
3.6
29.2
4.3
2. 0*
0.8
-
34.5
-
1.7*
1.9
2.1*
-
-
3.0*
-
-
-
-
-
-
-
-
5.9*
Location
Outlet B
3 ,a
12/10 1232 MST
D
2.64
52.9
95.3
3.5*
3. 6*
5.4
43.0
5.9
1.9*
1.7*
-
37.3
107*
1.3
2. 0*
2. 9*
E
1.32
81.2
128.6
3. 5*
3. 6*
6.6
92.4
13.1
2.1*
1.8*
-
90.3
1.9*
2.4
2. 2*
0.1
2. 9*
F
0.525
58.0
100.9
3.5
3. 6*
4.2
64. 1
10.2
2.1*
1.8*
-
48. 1
1.8*
1.4
2.2*
2. 4*
G
0.443
92.8
167. 0
6.2
4. 0*
5.3
109.2
15.2
2. 3*
2. 0*
-
85. 3
2. 0*
1.7
2. 5*
0. 1
2. 6*
H
489.9
1648.3
269.7
9.6
17.7
1231.3
116.9
6.1
5.4
0.2
708.2
4.9
3.8
20.7
0.7
5.7
5. 8*
0.4
0.4
5.7*
0.3 2.2
7.4
1.4
4.8* 5.1* 44.7
Concentration below reported detectable limits
Not detected
Dry Standard 21. 1 ° C, 760 mm Hg
C-3
-------
Run No.
112
(Concentration, micrograms /DSm3 )'
Location
Outlet A
12/10 1314 MST
_B
15. 1
c,
5.91
D
2.30
1. 35
G
0.580 0.338
H
Al
Si
S
Cl
K
Ca
Ti
V
Cr
Mn
Fe
Co
Ni
Cu
Zn
As
Se
Br
Rb
Sr
Zr
Ag
Ba
Pt
Au
Hg
Pb
5.7*
28.7
4. 1*
4. 5*
2.4
8.2
1.6*
0.9
1. 3*
-
16.4
_
1.2*
3.6
1.7
_
_.
1.6*
_
_
-
-
-
_
_
-
3.1*
5. 1
11. 1
3. 8*
4. 2*
2.3
6.4
2.5
1.8*
1 . 6*
-
1.6*
_
1 . 6*
1. 1
1. 9*
_
_
2. 5*
_
-
-
-
-
-
_
-
5.3*
42.0
78.6
3.8*
4.0*
5.9
29.8
5.3
2. 1*
1.9*
-
25.8
-
1.8*
1.2
2.2*
-
_
2.2*
_
-
-
-
-
-
_
-
4.4*
26. 1
45. 5
3.8
3.3*
4.9
22. 1
4.7
2.0
1.6*
-
19.9
-
1. 5*
0.6
1.9*
-
-
2. 5*
-
-
-
-
-
-
-
-
5. 0*
62. 5
114. 9
1.6
4. 1*
7.7
60.0
8.1
2.4*
2. 1*
-
53.1
-
2. 1*
2.3
1.3
-
-
2.9*
-
0.3
-
-
-
-
-
-
5. 8*
100.5
184. 0
8.2
4.2*
7. 5
113.2
16. 0
3.0
2. 1*
-
99.8
-
2. 1*
2.8
2. 5*
-
-
3. 0*
-
0. 3
-
-
-
-
-
0. 5
6. 0*
85. 9
205. 3
27.0
4.3*
7.7
160. 6
23.4
7.0
2. 2*
-
122.8
-
2.2*
1.6*
11.4
-
0. 1
2.7*
-
0.4
-
-
-
-
0.2
-
5. 1
60. 0
355.2
1482. 7
8.8=:
14. 1
1126. 5
5.6=:
5.6=:
42. 6
1. 2
787.2
-
39. 3
526.0
933.9
-
0. 2
4. 3=:
0. 3
1.6
—
-
4.9
-
-
1.4
10. 0 =
Concentration below reported detectable limit
Not detected
Dry Standard, 21. 1 ° C, 760 mm Hg
C-4
-------
Run No.
113
(Concentration, micrograms /DSm )
Location
Inlet 8
12/10 1207 MST
_B _C D .E _F .G H
16.0 6.17 2.45 1.45 0.657 0.28
Al
Si
S
Cl
K
Ca
Ti
V
Cr
Mn
Fe
Co
Ni
Cu
Zn
As
Se
Br
Rb
Sr
Zr
Ag
Ba
Pt
Au
Hg
o
Pb
2621. 5
4825. 5
17.4*
18.7*
236.8
1605.4
223.6
19.0
5.9*
0. 1
1111.4
-
5. 3*
12. 1
3.3
-
-
5. 7*
-
1.6
-
-
-
_
0.3
1.0
1 1 . 4*
5332.2
9630.8 1
19.8*
21.7*
575. 0
3987. 3
587.8
43.0
9.5*
0. 3
3537. 6
-
10.2*
40.2
1 2*
-
-
7.7*
-
4.0
-
-
-
_
0. 5
_
21.7*
8507.4
1334.7
21. 6*
21.3*
696. 5
5181. 9
743. 1
63.7
9. 8*
0.4
5139. 3
-
11.2*
8. 8*
13.4
-
-
8.7*
-
5.1
-
-
-
-
0. 6
_
23. 5*
3140.0
4580.7
15.7*
16.0*
265.5
1801. 9
250.6
24.8
7.4*
0.2
1568. 1
-
7. 6*
5.8*
8.8*
-
-
7. 3*
-
1.2
-
-
-
-
0.2
_
24.1
588. 1
941.8
12.5*
12. 6*
69.8
440. 5
70.2
15. 0
6. 4*
0. 1
456.3
-
6. 4*
9.3
5.0
-
-
8. 4*
-
0.3
-
-
-
-
-
0.2
16.6*
328. 3
551.0
22.7
13.6*
39.0
293.6
52.8
10. 1
6. 9*
-
274.5
-
6. 9*
6.5
5.3
-
0. 1
8. 6*
-
0. 3
-
-
-
-
-
_
17.0*
384.4
654.4
6.7
12.5*
33. 1
355. 1
56.9
8.4
6.4*
0.1
299.3
-
6.3*
2.3
7.4*
-
-
8.4
-
0.4
-
-
-
-
-
_
16.6*
863.0
2251.7
248.4
39. 3*
60. 1
1267.2
24. 7*
25.0*
22. 1*
-
790.8
-
20.0*
15.4*
29.8
-
-
30.2*
—
-
-
6. 7
-
-
-
59. 6*
* Concentration below reported detectable limit
- Not detected
a Dry Standard, 21. 1 ° C, 760 mm Hg
C-5
-------
Run No.
114
Location
Inlet 8
( C one entration,
Stage
D50
A
29.0
micrograms /DSm3 )
_B
14. 5
_C
5.34
D
2. 51
E
1.51
12/10 1116MST
JT
0.689
G
0.274
H
Elements
Al
Si
S
Cl
K
Ca
Ti
V
Cr
Mn
Fe
Co
Ni
Cu
Zn
As
Se
Br
Rb
Sr
Zr
Ag
Ba
Pt
Au
Hg
Pb
5765.2
9439.7
17.2*
18.4*
570.4
3648.2
492.5
41.4
17.4
0. 3
2898.0
-
6. 8*
5. 6*
7. 4*
-
-
12.2
0.5
4.7
-
-
-
-
0.7
4.2
13.9*
2334. 6
4111.9
14. 1*
15.4*
236.3
1795. 1
243. 6
19.3
6. 4*
0.2
1387.2
-
6. 7*
5. 3*
8.5
-
0.2
6. 4*
-
2. 1
-
-
-
-
-
1.4
14.3*
1867.0
2787.4
13.7*
14.0*
168.3
1299.0
168.5
17.2
6. 4*
0.2
1049.3
-
6. 6*
14.8
10. 1
-
0.1
7.3*
-
1.3
-
-
-
-
-
1.3
14.6*
1258.4
1865.0
12. 3*
1 2 . 6*
129. 3
820. 1
118.0
11.9
5. 9*
0.2
792. 1
-
6. 0*
9.5
6. 9*
-
-
7.0*
-
0.8
0.3
-
-
-
-
0.8
39.5
336.0
559.4
16.3*
16. 5*
41.6
307.8
43.7
9.5*
8. 5*
0. 1
311.8
-
8. 2*
3.5
4.0
-
-
16. 5*
-
-
-
-
-
-
-
-
32.6*
161.6
294.5
17.0*
17.2*
18.5
181.6
34.1
9. 9*
8. 9*
-
156. 6
-
8. 6*
6. 9*
9. 9*
-
-
17.0*
-
-
-
-
-
-
-
-
33.6*
295.8
597. 1
41.2
18. 0*
31.0
532.9
84.8
10.4*
9. 2*
0.2
419.6
-
8. 9*
7.0*
7.7
-
-
20. 1*
-
-
_
-
-
-
-
-
39. 6*
436. 6
1439.0
238. 7
33. 0:
26. 5=:
1037.9
20.7
21.0-
18. 5--
-
524.8
-
16. 8'
13.0 =
28.0
_
-
24. 8'
-
-
-
-
5.7
-
-
-
49.0 =
Concentration below reported detectable limit
Not detected
Dry Standard, 21. 1 ° C, 760 mm Hg
C-6
-------
Run No.
115
Location
Outlet C
Stage A
DC:
:ration,
A
27. 3
a a 12/10 1505 MST
micrograms /DSm )
_B _C D _E _F jG H
13.7 5.26 1.89 1.29 0.555 0.414
Elements
Al
Si
S
Cl
K
Ca
Ti
V
Cr
Mn
Fe
Co
Ni
Cu
Zn
As
Se
Br
Rb
Sr
Zr
Ag
Da
Pt
Au
Hg
Pb
P
8. 0*
8.0
5.8*
4. 5
3. 3
2.9
2. 3*
2. 3*
1. 9*
-
9.8
-
1.6*
1. 3*
1.8*
-
-
3. 7*
-
-
-
-
-
-
-
-
7. 2*
-
4.7
6. 8*
6.1
6. 4*
3.6
2. 6
3.1
3.6
2. 5*
-
3.8
-
2.4*
1.9*
2. 7*
-
-
5.7*
• -
-
-
-
-
-
-
-
12.0*
0.4
4.5
24.0
5. 9*
6. 2*
2.8
8.4
3. 3*
2.7
2.9*
-
11.0
-
2.8*
2.3*
3.3*
-
-
5.6*
-
-
-
-
-
-
-
-
11.1*
—
59.3
90.0
6. 1*
6. 4*
7.8
42.6
7.2
3. 4*
3.0*
-
40.8
-
2. 9*
2. 4*
3. 4*
-
-
5.0*
-
-
-
-
-
-
-
-
10. 1*
-
43.5
69.2
4. 8*
4. 9*
10.8
46.9
10.2
2. 8*
2. 5*
-
54.7
-
2.4*
2.0*
2. 8*
-
-
4. 7*
-
-
-
-
-
-
-
-
9.2*
-
57.4
117.9
6. 3*
6. 4*
10.2
65.0
8.7
5.8
3.3*
-
59.7
-
3.2*
2. 6*
3.7*
-
-
6. 4*
-
-
-
-
-
-
-
.
12.6*
-
63. 1
123. 1
5.0
7. 1*
5.4
83.7
13.7
4. 1*
3. 6*
-
81.4
-
3. 5*
2. 8*
4. 1*
-
-
7. 2*
-
-
-
-
-
-
-
-
14.3
-
16.5
123. 1
600.7
10.5
8.6
207.5
36.7
6.7
19.3
0.3
419.7
-
16.6
1476.5
678.4
-
-
7.8
-
-
-
-
-
-
-
40.3
-
Concentration below reported detectable limit
Not detected
Dry Standard, 21. 1° C, 760 mm Hg
C-7
-------
Run No.
116
(Concentration, micrograms/DSm )
a i a
Location
Outlet B
12/10 1530 MST
B
D
H
D50 28.4
14.2
5.58 2.32 1.44 0.662 0.467
Elements
Al
Si
S
Cl
K
Ca
Ti
V
Cr
Mn
Fe
Co
Ni
Cu
Zn
As
Se
Br
Rb
Sr
Zr
Ag
Ba
Pt
Au
"g
Pb
12
10
8
9
6
5
4
3
2
4
2
1
2
4
9
. 0*
. 5 *
. 6*
. 2*
.5
.9
.2
. 3*
. 9*
-
. 1
-
.4*
.9*
.7*
_
_
. 9*
_
_
_
-
_
—
_
_
. 6*
10
20
8
15
5
10
4
4
3
5
3
2
3
7
15
. 9*
.0
. 2*
.8
.3
.4
.0*
.3
. 5*
-
.7
-
. 4*
. 7*
.8*
-
_
. 3*
_
_
_
_
_
_
_
-
.3*
39.3
69.2
9.2
8. 8*
6. 0*
31.7
7.3
4.7*
4.2*
-
27.2
-
4. 1*
3. 3*
4. 6*
-
—
8.5*
_
_
_
_
_
_
_
-
17.0*
104.0
186. 3
10. 3*
10.7*
12. 1
88.2
12.9
5.9
5.0*
0.2
111.2
_
4. 8*
3. 8*
5.5*
-
_
11. 5*
-
_
_
-
_
_
_
-
22. 9*
85.2
152.4
8. 8*
8. 9*
7.4
75.0
10.8
5.2*
4. 6*
-
89.4
_
4. 4*
1.3
5.0*
-.
_
10.9*
_
_
..
-
_
..
_
-
21.5*
123
219
8
8
12
136
23
5
4
118
4
2
4
9
19
.0
.6
.7
.2*
.9
.4
.0
.1
.2*
-
.9
_
. 0*
.7
.5
_
_
.6*
_
_
_
-
_
_
_
-
. 0*
15.5
59.8
19.2
7. 0*
5. I*
12.2
8.2
4. 1*
3. 6*
-
37.8
-
3. 5*
2.8
7. 1
-
_
7. 1*
-
_
_
-
_
_
_
-
14. 1*
15. 6
73.7
307.7
11. 1
7.4
106. 4
6.9
7.0
24.6
0.4
287.4
_
11. 1
179.9
243.8
-
-.
8.0
_
_
„
-
2.5
_
_
-
17. 9
Concentration below reported detectable limit
Not detected
Dry Standard, 21. 1 ° C, 760 mm Hg
C-8
-------
Run No. 117 Location Outlet B
ir~ 4. *.- • /T.O 3va 12/10 1431 MST
(Concentration, micrograms / DSm )
_J3_CE>E;_F_GH
28.2 14.2 5.23 2.57 1.29 0.513 0.434
Elements
Al
Si
S
Cl
K
Ca
Ti
V
Cr
Mn
Fe
Co
Ni
Cu
Zn
As
Se
Br
Rb
Sr
Zr
Ag
Ba
Pt
Au
Hg
Pb
15.2*
18.9
10.9*
11.7*
5.7
11.1
5.6
4. 2*
3. 6*
-
9.8
-
3. 1*
2. 4*
3.5*
-
-
6. 0*
-
-
-
-
-
-
-
-
11.7*
10.5*
34.3
7.8*
5.7
3. 3
9.4
3. 8*
3. 7*
3. 3*
-
17.2
-
3. 2*
2. 6*
2.4
-
-
4. 3*
-
-
-
-
-
-
-
-
9. 1*
68.2
143.5
7.2*
7. 5*
9.2
52.3
11.7
4. 0*
3. 6*
0. 1
56.9
-
3.5*
2. 8*
4.0*
-
-
4. 9*
_
-
-
-
-
-
-
-
9. 9*
206.0
338.5
9. 0*
9. 3*
27.0
192.6
31.8
5.0*
4. 4*
0.1
238.5
-
4. 4*
3. 5*
5.0*
-
-
6.7*
-
0.7
-
-
-
-
0.5
0.5
13.4*
157.7
252.9
2.9
6. 8*
15.2
163.5
25.9
4. 0*
3.5*
0.2
189.2
-
3. 4*
2. 8*
4.0
-
-
4. 9*
-
0.5
-
-
-
-
-
0.4
9. 6*
122.5
223.7
10. I
7. 2*
14. 1
171.4
24.9
9.8
3.7*
0.2
145.6
-
3. 6*
1.2
4. 2*
-
-
4. 9*
-
0.4
-
-
-
-
0.2
-
9. 6*
41.8
116. 1
22. 1
6. 6*
8.5
74.1
13.0
4.8
3. 4*
-
59.4
-
3. 4*
3.8
10.4
-
-
4. 4*
-
-
-
-
-
-
-
-
8. 7*
34.5
68.0
810. 1
15. 3
9.0
225. 6
9.6
9.7
47.5
0.6
519.2
-
22.6
902.2
703.5
-
-
17.1
-
-
_
-
2.0
-
-
-
54. 1
Concentration below reported detectable limit
Not detected
Dry Standard, 21.1°C, 760 mm Hg
C-9
-------
Run No.
118
(Concentration, micrograms /DSm )
a , a
B
D
Location Outlet C
12/10 1630 MST
D50 20.7 10.3 4.02 1.54 0.897 0.367 0.202
Elements
H
Al
Si
S
Cl
K
Ca
Ti
V
Cr
Mn
Fe
Co
Ni
Cu
Zn
As
Se
Br
Rb
Sr
Zr
Ag
Ba
Pt
Au
Hg
Pb
P
8. 9*
7.8*
6. 4*
6. 8*
3. 8*
2.7
2.6*
2. 5*
2.1*
0.1
8.2
0.1
0.6
1 . 4*
2.1*
_
_
2. 6*
_
_
_
_
_
_
_
_
5. I*
0.1
8.9
9.6
6. 8=:=
7. 4*
4.3
7.1
3. 3*
4. 5
2. 9*
-
11.3
_
2.8*
2.2*
2.1
_
_
4.0*
_
_
_
_
_
_
_
_
8. 4*
-
9.7
19.8
6. 0*
6. 3*
4. 3*
10.5
3.7
3. 4*
3. 0*
_
8.0
_
3. 0*
2. 4*
3.4*
_
_
4.2*
_
_
^
-.
-
_
_
-
8. 4*
-
7.9
5. 8*
5. 4*
5.7*
4.4
4.5
3. 0*
3. 0*
2. 7*
0. 1
3.2
_
2. 6*
2.1*
3. 1 *
_
_
4. 3 *
_
_
_
-
0.5
_
_
-
8. 5*
-
9.5
12.5
6.1*
6. 2*
4. 5*
15.4
3. 6*
3. 6*
3.2*
_
15.7
1.7
2.4*
3. 6*
81.7
156. 5
6.8
6. 5*
7.7
96.8
13.9
3. 8*
3. 3*
_
75.1
2.0
3.2
3. 7*
29.9
96. 3
710.0
14. 1
8.7
235. 1
8. 8
8. 9
37.2
0. 6
429.0
9.7
867.5
443.9
4.7* 4.9* 8.1 =
0. 6
2.8
9.4* 9.6* 89.3
* Concentration below reported detectable limit
- Not detected
a Dry Standard, 21. 1 ° C, 760 mm Hg
C-10
-------
Run No.
119
(Concentration, micrograms/DSm3)
3 v a
Location
Inlet 8
12/10 1530 MST
_B _C D JE _F C H
16.6 6.38 2.54 1.50 0.682 0.292
Al
Si
S
Cl
K
Ca
Ti
V
Cr
Mn
Fe
Co
Ni
Cu
Zn
As
Se
Br
Rb
Sr
Zr
Ag
Ba
Pt
Au
Hg
Pb
939
2577
36
39
102
612
71
14
12
463
10
6
11
15
31
.4
. 1
. 5*
.4*
.8
.4
. 1
. 5*
. 0*
-
.5
-
. 3*
.6
. 7*
-
-
. 7*
-
-
_
-
_
-
_
-
. 0*
575. 1
1283.2
38. 3*
42. 3*
64.9
488.7
50.6
18. 3*
16. 1*
-
375.7
-
8.6
12.2*
1 8. 1 *
-
-
23.2*
-
_
_
-
_
0.4
_
-
48. 8*
1757.
3244.
45.
46.
188.
1690.
204.
24.
22.
1495.
22.
17.
25.
36.
0.
2.
126.
8
8
2*
9*
2
6
3
8*
5
4
0*
9=;=
8*
5*
9
8
2
1355
2511
38
40
182
1153
154
30
18
0
1189
18
15
21
30
0
0
61
.9
.4
. 7*
.3*
.5
.6
.6
.4
.6*
.2
.4
-
.8*
. 0*
.4*
-
-
. 6*
_
.6
_
-
_
.8
_
-
. 1*
529.3
972.6
26. 2*
26.7*
81.8
577.2
86.0
19.8
1 3. 4*
0.2
823. 6
-
8.5
19.0
15.4*
-
_
17.7*
_
0.4
_
_
—
0.3
—
. _
35. 1*
85.9
154.0
22.4*
23.0*
16.7*
115.6
17.5
13.3*
1 1 . 6*
-
114.2
_
11.2*
3.5
13.4*
-
_
16.2*
w
_
_
,_
_
0.2
_
_
32.0*
207.4
394.6
23.8
25.2*
36. 1
201.5
31.7
14.4*
12. 6*
-
176.2
_
6.2
23. 6
132.0
_
_
17. 1*
_
_
_
_
_
__
_
^
33. 7*
182.2
375.8
252.9
58.4*
46. 3*
550.2
68.2
43.2
32. 6*
_
394.7
—
29.6*
148.6
702.2
-
_
48. 0*
_
_
_
94. 8*
* Concentration below reported detectable limit
- Not detected
a Dry Standard, 21.1° C, 760 mm Hg
C-ll
-------
Run No.
120
(Concentration, micrograms /DSm )
3, a
Location Inlet 13
12/10 1617 MST
D
'BO
31.4 15.7
D
E
5.79 2.73 1.65 0.755 0.305
H
Elements
Al
Si
S
Cl
K
Ca
Ti
V
Cr
Mn
Fe
Co
Ni
Cu
Zn
As
Se
Br
Rb
Sr
Zr
Ag
Ba
Pt
Au
Hg
Pb
223.5
467.3
14.9
31.5*
26. 1
138.4
13.7
11.4*
9. 6*
-
98.1
-
8.0*
6.3*
9. 3*
-
-
11.5*
-
-
-
-
-
0.2
-
-
22.8*
293.9
683.9
31.5*
34.7*
27.0
244.0
36.1
15.0*
13.2*
-
185.3
-
5.1
7.3
14. 9*
-
-
19.1*
-
-
-
-
-
-
-
-
40. 3*
1529.4
2407. 8
24. 2*
25. 2*
185. 3
1558. 7
207. 5
14.3
11.6*
0.1
1469.6
-
11.6*
9. 3*
13.3*
-
_
14. 9*
-
1.2
-
-
-
-
-
1.3
29. 7*
1810.7
2807.6
26. 1*
27.0*
227.7
1651.0
229.5
31.8
12.7*
0.2
1910.9
-
12.6*
9. 9*
14.4*
-
_
15.4*
-
1.5
-
-
-
-
-
1.0
30. 6*
487. 0
821.7
24. 0*
24. 5*
71. 5
513.2
82.6
14.2*
12.4*
0.1
631. 5
-
7.2
7.7
14.2
-
_
16.6*
-
0.6
-
-
-
0.2
-
-
32. 8*
218. 1
398. 8
24. 1*
24. 6*
24. 3
285.9
34.2
14.2*
12. 5*
-
331.9
-
14.3
5.8
11. 8
-
_
16. 5*
-
-
-
-
-
-
-
-
32. 7*
305. 1
613.8
24. 2*
24. 7*
20.8
315.2
34.7
14.2*
12.4*
_
308. 1
-
5.7
9. 6*
14. 3*
_
_
17.4*
-
-
-
-
-
-
_
-
34. 4*
* Concentration below reported detectable limit
- Not detected
a Dry Standard, 21. 1° C, 760 mm Hg
46.2
75.9 =
51.1 =
50. 9'
57.3
37.9
72.6
32. 3'
28.5 =
24.7 =
25. 9:
19. 9'
25.4=:
42. 0-
83.0 =
C-12
-------
Run No.
121
3 a
3
(Concentration, micrograms /DSm )
Location
Outlet B
12/11 1216 MST
stage A
B
D
G
H
D
50
27.137 13.6
5.34 2.22 1.376 0.630 0.444
Elements
Al
Si
S
Cl
K
Ca
Ti
V
Cr
Mn
Fe
Co
Ni
Cu
Zn
As
Se
Br
Rb
Sr
Zr
Ag
Ba
Pt
Au
Hg
Pb
7.2
20. 3
2.2
5. 5*
2.4
10. 8
2. 1*
2.0*
1.7*
-
9.2
_
0.7
2.7
1. 7*
-
_
2. 0*
_
_
_
_
_
_
_
_
3. 9*
7. 4*
6. 5*
3.7
13.0
3.1
10.8
2. 6*
2.9
2. 3*
-
8.3
0. 1
2. 2*
1.1
2. 5*
-
..
3. 3*
—
_
-
_
_
-
_
_
6. 9*
45.4
98.9
6.7*
7.1*
4. 9*
74.7
3. 9*
3. 9*
3. 4*
0.3
55.7
3. 2*
1.7
3. 7*
-
_
4.9*
_
_
-
-
2.1
0.7
_
_
9. 7*
185.6
283.8
5.4*
5.6*
17.0
174.8
22.3
3.8
2. 6*
0.2
163.7
_
2. 5*
2.0*
2. 9*
-
_
3. 6*
_
0. 5
-
-
_
-
_
0.5
6.0
146.5
230.4
3.5
4. 8*
8.5
142.6
18.4
2. 8*
2. 4*
0.1
112. 6
0.2
1.8
1.8
2. 8*
-
-
3. 2*
_
0.4
-
-
-
0.3
.-
_
6. 4*
200.2
303.9
13.9
4. 6*
10.2
239.2
30.7
7.5
2. 3*
0.1
173.4
_
2. 2*
1.8
3. 1
-
-
2. 8*
-
0.8
-
-
-
-
-
0.5
5. 5*
100.0
242.7
36.5
4. 7*
5.0
265.5
2.7*
2.7*
2. 3*
0.1
155. 1
_
1.6
1.8*
4.0
-
-
2.9*
_
0.9
-
-
5.0
0.2
-
-
5.7*
20. 4*
243.9
357.2
11.7*
9. 4*
177. 1
47.2
7. 4*
24.9
0. 3
568. 1
_
5. 9*
152.9
164. 1
-
-
9. 5*
-
-
-
-
7.1
-
-
-
45.2
Concentration below reported detectable limit
Not detected
Dry Standard, 21. 1 ° C, 760 mm Hg
C-13
-------
Run No.
122
Location
Outlet C
3 a
(Concentration, micrograms /DSm )
Stage
D5o
A
27.7
B
13.9
C
5.33
D
1.91
E
1.30
12/i:
F
0.559
I 1215 MST
G
0.417
H
Elements
Al
Si
S
Cl
K
Ca
Ti
V
Cr
Mn
Fe
Co
Ni
Cu
Zn
As
Se
Br
Rb
Sr
Zr
Ag
Ba
Pt
Au
Hg
Pb
4.0
7.8
6.8
5. 8*
2.5
14.2
2.2*
3.0
1.8*
_
5.3
_
0.7
1.2*
1.7*
_
_
2. 1*
_
_
-
-
_
_
_
_
4.2*
6. 5*
5. 6*
2.6
3.4
2.7
5.4
2.3*
2.3*
2.0*
_
8.6
-
1.9*
1.3
2. 2*
_
_
3.0*
_
-
-
-
-
-
_
-
6. 4*
6.4
6.3
4. 8*
5.0*
3. 4*
11.8
2. 7*
2.7*
2. 3*
-
6.6
-
2. 3*
1. 8*
2. 7*
-
_
3. 3*
_
-
-
-
-
-
-
-
6. 6*
83.2
141.8
5.1*
5. 3*
8.4
81.5
10.0
2. 8*
2. 5*
0.2
73. 3
-
1.0
1.8
2.8*
-
-
3. 5*
-
-
-
-
-
0.2
-
-
6. 9*
82.3
136.9
4. 8*
4. 9*
8.1
91.9
13. 1
4.2
2.5*
-
81.0
-
2.4*
1.9*
2. 8*
-
-
3. 4*
-
-
-
-
-
-
-
-
6. 7*
88.7
155.4
2.3
5. 0*
6. 1
109.4
14.5
4.4
2. 5*
-
78.9
-
1.4
1. 9*
2. 9*
-
-
3. 5*
-
-
-
-
-
-
-
-
6. 9*
32. 3
64. 1
2.2
4.5*
1.8
50. 5
5.7
2. 6*
2. 3*
-
32.4
-
2.2*
1.7*
2. 6*
-
-
3.2*
-
-
-
-
-
-
-
-
6.3*
5 .0
177.0
725.0
11.4=
18.5
236.9
64. 5
7.2:
79.8
1. 1
518.8
-
18.7
1108.6
651.3
-
0.4
8.2
-
1.6
-
-
0.9
-
-
-
105.7
-•'•• Concentration below reported detectable limit
- Not detected
a Dry Standard, 21. 1° C, 760 mm Hg
C-14
-------
Run No.
123
(Concentration, micrograms /DSm3 )
Location Inlet 13
12/11 1215 MST
D
E
H
D50 34.5 17.3
6.66 2.66 1.57 0.716 0.308
Elements
Al 5775. 5
Si 9746. 9
S 35. 9*
Cl 38. 8*
K 491.0
Ca 3440. 1
Ti 415.7
V 27.9
Cr 12.5*
Mn 0.2
Fe 2035. 1
Co
Ni 11.1 *
Cu 30.4
Zn 12.2*
As
Se
Br 13.4*
Rb
Sr 2. 5
Zr 0.6
Ag
Ba
Pt
Au
Hg 1-9
Pb 26.7*
1737.3
3227. 0
30. 7*
33.9*
161. 5
1167. 1
146. 9
15. 1*
13.2*
-
780.7
-
13. 3
14. 1
14.5*
-
-
17. 3*
-
0. 6
-
-
-
0.2
-
-
36.7*
4064.2
5972.3
33.1*
33. 5*
432.6
3893.6
507.8
54.7
15.5*
0.3
3826.8
-
1 6. 6*
39.6
18.2*
-
-
17.0*
-
-
-
-
-
0.6
-
-
262.0
3735.3
5301.8
32.7*
33.4*
420.9
3474. 6
464.0
62.2
15.6*
-
3736.0
-
16.5*
37.3
33.1
-
-
18.0*
-
-
-
-
-
-
-
-
36. 1*
781.0
1309. 1
25.7*
26. 1*
101. 1
846.0
130.0
34.6
13.2*
0. 1
869.2
-
19.0
10. 6*
14.8*
-
-
17. 1*
-
0. 5
-
-
-
-
-
33. 8*
227.7
435.7
19.7
24. 1*
35.6
327.9
58. 1
41.5
12.2*
-
313.4
-
11.9*
9. 5*
13.6*
-
-
15.8*
-
-
-
-
-
-
-
-
31.1*
686.3
1505.8
156.7
31.0*
49. 1
1124.8
110.0
17.4*
15.5*
0.1
808. 5
-
15.2*
12. 1*
17.4*
-
-
20. 8*
-
0.4
-
-
1.6
-
-
0.6
41.0*
400.2
1643.7
459.1
59.8*
29.5
1412.9
50.0
37. 8*
33. 5*
-
810.0
-
30. 3*
23. 6*
20. 3*
-
-
46. 2*
-
-
-
-
3.4
-
-
-
91.2*
Concentration below reported detectable limit
Not detected
Dry Standard, 21. 1° C, 760 mm Hg
C-15
-------
Run No.
124
(Concentration, micrograms /DSm )
_B
17.2
Location
Inlet 13
11/12 1240 MST
C D E F G H
6.34 2.99 1.81 0.835 0.342
Al
Si
S
Cl
K
Ca
Ti
V
Cr
Mn
Fe
Co
Ni
Cu
Zn
As
Se
Br
Rb
Sr
Zr
Ag
Ba
Pt
Au
Hg
o
Pb
2341.8
4555.4
28. 4*
30.6=:=
186.9
1373.2
154.0
38.6
9. 7*
0. 1
762.1
_
11.8
6. 8*
9. 3*
—
_
12.5*
_
0.7
_
-
_
.
0.4
24. 6*
2228.0
3954.3
28. 9*
31.8*
206.3
1497.6
195.7
27.8
12.8*
0.1
997.3
_
12.6*
22.0
13.8*
-
—
15.9*
_
0.8
-
-
-
0.2
_
0.7
33.5*
1441.7
2321.9
23.2*
24. 0*
152.0
1384.2
175.7
37. 5
11.2*
0.1
1060. 1
_
11.5*
9. 3*
12.7*
-
_
15.7*
_
0. 8
-
-
-
-
_
0.7
31.5*
3111.2
4442. 3
31.4*
32.2*
289.8
2439. 5
324.6
38.9
14.7*
0.2
2075.8
-
15.5*
12. 5*
17.3*
-
_
19.7*
-
1.2
-
-
-
-
_
1.4
39. 3*
409.9
712.9
23. 5*
23.8*
47.8
469.2
69.8
34.0
12. 1*
-
486.4
-
11.8*
9. 5*
13. 5*
-
-
17. 3*
-
-
-
-
-
-
-
_
34.2*
174. 1
349.8 :
19.9
24. 8*
48.9
331.8
70.4
29. 1
9.4
0.1
374.8
-
12. 3*
9. 8*
14. 1*
-
-
17. 6*
-
-
-
-
—
-
-
0.2
34. 7*
616.9
1115. 6
97.9
24. 8*
38.8
846.4
105.4
14. 0*
10.2
-
537.2
-
12.2*
9. 8*
12. 6
—
0.0
16.0*
-
0. 3
-
—
~
-
-
0.3
31.7*
96. 6*
1706. 8
497.2
55.2*
55.7
1470.7
34. 3*
35.0*
30.8*
-
773.2
-
28. 1=:
16.0
25.3
—
-
42.5-'
—
-
—
4 Q
~ « /
-
—
-
84. 2~
Concentration below reported detectable limit
- Not detected
a Dry Standard, 21. 1 ° C, 760 mm Hg
C-16
-------
TABLE C17. COAL ANALYSIS
Date
Moisture, Percent
Volatile Matter, Percent
Fixed Carbon, Percent
C, Percent
H, Percent
N, Percent
P, Percent
S, Percent
Heat of Combustion
BTU/lb
12/10/74
8. 92 _+0.08
41.0 J; 0. 1
40.4 + 0. 1
63.4 _+ 0. 7
4. 69 + 0.02
1. 61 _+ 0.09
0.23
0. 43 -1- 0. 02
11, 187
12/11/74
13.4 + 0. 1
43. 5 + 0. 1
35. 7 _+ 0. 1
63.4 +2.0
5.2 + 0.3
1.62 + 0.06
0.23
0.45 + 0.02
10,636
C-17
-------
APPENDIX D
ENGINEERING ANALYSIS OF THE CHEROKEE #3 SCRUBBER
-------
ENGINEERING ANALYSIS
OF
THE CHEROKEE #3
SCRUBBER
MAY 1975
PREPARED FOR METEOROLOGY RESEARCH, INC.
BY STEARNS-ROGER INC.
D-l
-------
TABLE OF CONTENTS
SECTION 1 - INTRODUCTION
SECTION 2 - CAPITAL COSTS
SECTION 3 - OPERATING COSTS
SECTION 4 - MAJOR MAINTENANCE AND
OPERATING PROBLEMS
SECTION 5 - SCRUBBER RELIABILITY
SECTION 6 - ESTIMATE OF A PROBLEM
FREE SCRUBBER
D-2
-------
SECTION 1
INTRODUCTION
In October of 1972, construction was completed on a scrubber to remove
particulate matter from the flue gas emitting from the #3 boiler at
Public Service Company of Colorado's Cherokee Station located in north-
east Denver. This scrubber is part of a series of scrubbers and other
pollution control devices that PSCC has installed in their efforts to
provide an environmentally acceptable flue gas discharge from this
station.
The purpose of this report is to provide an engineering analysis of
the design and operation of the scrubber. This analysis includes:
1. Operating and capital costs
2. Review of operating and maintenance problems
3. Determination of scrubber reliability
4. Estimate of the cost to produce a "problem-free" scrubber
This report complements, the testing program performed on the scrubber
to aid in the total evaluation of its overall effectiveness.
1.1 Description of the Cherokee #3 Scrubber
A scrubber is a device to remove a pollutant from a gas stream by
bringing a liquor in contact with the flowing gas. The Cherokee #3
Scrubber is a vessel that contains many plastic spheres held in place
between a series of grids. With the proper balance of downward liquid
flow and upward gas flow, these spheres remain in a constant state of
motion. These spheres provide surface area for the liquid and gas
phases to come into contact.
A flow diagram of the Cherokee #3 scrubber system is shown in Figure 1.
The flue gas from the #3 boiler passes through a mechanical collector,
an electrostatic precipitator, and into the two parallel operating in-
duced draft fans. The gas can either go directly to the stack through
the bypass damper or enter the scrubber system. This bypass arrange-
ment allows the scrubber operation to be independent of the boiler opera-
tion.
The scrubber body consists of three separate sections labeled A, B, and
C. A and C are designed to handle 20% each of the normal gas flow and
B is designed to handle 60%. All three sections can operate independ-
ently of each other. This provides flexibility of operation at lower
gas flows.
D-3
-------
/
Multl-lMf
Control
Dampen
. Mechanic*!
\ to 11 re tor
Flue C*l
F r ura
_.5F
==[p^'
Hlit
El Imlnator
Wash
. Isolation
/ Dampen
_ Block/ByPao
/ Damper
Hakc-up
Water
Prea«turati>r
-€/
^
•_j
r
j
i
\ —ivw-
E-3
Contac ting
<:pti«t-n~
Rahcac St«n
HUt
Electto»t«t Ic
Proc IpH HI 'i
'' Induced Draft
Knnn
i Scrubber Boostrr
-— «_ m ^ •*< I rcut a 11 an
^^'
Slurry Dr.iw.off
Figure 1
Cherokee #3 Scrubber System Flow Diagram
-------
Under design conditions, 610,000 ACFM of flue gas enters the scrubber
booster fans. After exiting the booster fans, the gas enters the pre-
saturator and is sprayed with 380 GPM of make-up water. This water
cools the gas from 280° F down to its saturation temperature which is
approximately 125° F. This is done to prevent heat damage to the
rubber lining in the scrubber and to saturate the flue gas prior to
the scrubbing phase.
The gas then enters the scrubber body and is contacted with the re-
circulating liquor which enters the top of the scrubber through a
header equipped with a set of spray nozzles. As the gas is contacted
with the liquor, most of the fine particulate matter still remain-
ing in the gas is wetted and removed by the liquor. Some amount of
S(>2 is also absorbed and a low pH slurry is produced. This liquid
slurry flows out the bottom of the scrubber where it is returned to
the header by the recirculation pumps. Under normal operation, 225
GPM of slurry is continually purged from the system to prevent a
buildup of scrubbed particles in the recirculated liquor. The slurry
that is removed from the scrubber is pumped to an ash pond for dis-
posal.
The scrubbed gas travels through a set of mist eliminators where
entrained moisture is mechanically removed. The mist eliminators
are periodically washed by water sprays to prevent any accumulation
of solids on their blades.
The gas enters the reheater section and is heated by use of steam
coils before entering the stack. The gas is reheated for two reasons;
(1) to raise the temperature sufficiently above the dew point of the
flue gas to prevent corrosion of the ductwork and stack lining due
to condensation and (2) to raise the temperature of the flue gas to
give it thermal drive to discharge from the stack. The steam coils
are equipped with two sets of sobtblowers to help maintain a clean
surface on the coils. The heated, scrubbed gas then exits through
the stack after entering the stack ductwork downstream of the by-
pass damper.
D-5
-------
SECTION 2
CAPITAL COSTS
This section gives a breakdown of the capital costs required for the
design, engineering and construction of the Cherokee #3 scrubber.
This data is presented in Table 1. The total cost for the scrubber
was $4,400,000 which amounts to an installed cost based on a name-
plate rating of 150 MW of $29/KW. Based on the rated gas flow of
610,000 ACFM (280° F, 24.7" Hg) or 360,000 SCFM (70° F, 30" Hg),
the cost is equal to $7.10/1000 ACFM or $12.00/1000 SCFM. This
figure is the total installed cost of the scrubber which was com-
pleted in 1972. Since prices have escalated since then, the cost
of a similar scrubber would be higher today. The 1975 cost of a
similar scrubber installation, with some changes, is presented in
Section 6.
The source of data for the capital costs was both PSCC's and Steams-
Roger's accounting records. Both cost sources were necessary because
all of the major items were purchased directly by PSCC. These account-
ing records contain a separate charge for labor and material for some
items. However, items that were done by subcontractors have labor
and material charges combined. Because it was impossible to separate
labor and material for all items, Table 1 gives just an installed
cost for each account.
D-6
-------
TABLE NO. 1
CHEROKEE 13 SCRUBBER
CAPITAL COST BREAKDOWN
1972 DOLLARS
ACCOUNT
Excavation and Earthwork
Concrete
Structural St«el and Buildings
Process Equipment
Scrubber Vessel
Ductwork
Prcsaturator
Scrubber Fans and Motors
Sootblowers
Soot blowing Air Compressors
Reheater
Dampers and Isolation Gates
Recirculatlon Pumps and Kotors
Miscellaneous Pumps and Motors
Stack Lining
Instrument Air Compressors
Monitoring Equipment
Miscellaneous Equipment
Piping
Electrical
Painting
Instrumentation
Insulation
Indirect Field Coats (Includes: Field
Supervision and Payroll Expenses;
Construction Supplies; Temporary
Facilities; Demolition; Construction
Equipment)
PSCC Overhead Costs
Enginearlas;
Pre Start-up and Revision*
Post Start-up and Maintenance
Contractor Fee
Interest During Construction
TOTAL
INSTALLED COST
5 19.100
100,800
324.300
$463.900
224. 600
65,600
194.900
50,700
56,100
42,200
53,400
48,900
6,500
36.900
10,700
16,400
16,500 1,337,300
235,000
444 , 300
28,000
263,900
110,700
385,000
74,600
404.400
67.800
143,800
369,000
69,300
$4.377,300
X
0.4
2.3
7.4
:io.6
5.4
.0.2
0.6
6.0
2.5
8.8
1.7
9.2
1.6
3.3
8.4
1.6
100.0
D-7
-------
SECTION 3
OPERATING COSTS
This section gives a breakdown of the costs involved in operating
the #3 scrubber at PSCC's Cherokee Plant. A summary of these costs
is presented in Table 2. These costs are direct costs only and do
not include any indirect costs, such as general plant overhead or
charges against capital (i.e.. depreciation, interest, taxes, etc.).
There are also no charges for general engineering work done by PSCC's
Environmental Engineering and Planning Department. The total direct
operating costs are approximately $495,000/year. Based on 75% avail-
ability of the scrubber, this amounts to a cost of 0.50 mills/KWH.
3.1 List of operating cost items
3.1.1 Operating labor and operating supervision
3.1.2 Utilities
3.1.3 Maintenance costs
3.1.4 Operating supplies
3.1.5 Miscellaneous
3.2 Operating labor and operating supervision
Operating labor consists of two functions, an inside control operator
and an outside auxiliary tender. Both men have responsibility for
operating other boiler equipment and the other two scrubbers at Cherokee.
Therefore, it was necessary to have PSCC estimate how much of their
time was spent on the #3 scrubber. They estimated that the control
operator spends approximately 207» of his time on all three scrubbers.
They also estimated that 507» of the auxiliary tender's time was spent
on all three scrubbers. Using this as a basis, the yearly man-hour
requirements for the Cherokee #3 scrubber only are 585 for the control
operator and 1,460 for the auxiliary tender. The wage rates given in
Table 3 are the current wage scale for PSCC operating personnel with
267. added for overhead. The 267o is the figure used by PSCC for payroll
benefits such as vacations, insurance programs, etc.
The operating supervision costs are also based on PSCC's estimates.
They estimate that about 5 hours per week of the shift supervisor's
time is spent on the #3 scrubber. Wage rates and overhead costs are
from the same source as that for operating labor.
3.3 Utilities
As can be seen from Table 3, utilities make up over 607, of the total
operating costs. The usage rates were obtained from PSCC on an hourly
basis. These rates were based on the scrubber system ^running at 1007.
D-8
-------
ti
TABLE NO. 2
MAINTENANCE COSTS FOR CHEROKEE 13 SCRUBBER
SECTION
Scrubber Tover I Reheat
Booster Fan 3A
Booster Fau 3B
Duct and Breeching
Reclrculatioa Punp 3A
Recirculation 3B1
Recirculation Punp 3B2
Recirculation Tump 3B3
Recurculatloa Pump 3C
Make-up Puap i*
Make-up Puap 3B
Slurry Puep 3A
Slurry f'urap 3fc
Piping Valves
Soot Blowers
Instruments & Controls **
High Pressure Steaa ***
4TH qu
1*
LABOR
1,092.00
.00
.00
1,987.00
1,327.00
48.00
763.00
229.00
.00
.00
116.00
.00
.00
4,040.00
.00
53.00
47.00
$9,702.00
ARTER
73
SUPPLIES
AND EXPENSE
9.14
9.40
.00
45.48
29.25
.34
20. 52
5.28
.00
.00
.63
21.14
.00
314.01
171.95
.33
.26
$627.7.)
IST qu
19
LABOR
489.00
1,036.00
1,351.00
3,495.00
94.00
.00
416.00
174.00
703.00
.00
.00
.00
24 8 . 00
2,729.00
.00
215.00
236.00
$11,186.00
ARTER
74
SUPPLIES
AND EXPENSE
•7,218.76
258.27
9.81
474.81
63.28
.00
10.54
.69
9.63
.00
.00
.00
63.43
373.21
8.43
85.81
28.12
$8.605.04
2ND qu
19
LABOR
.00
.00
68.00
111.00
.00
.00
.00
1,. 388. 00
627.00
110.00
85.00
511.00
520.00
2,137.00
458.00
.00
74.00
$6,089.00
ARTER
74
SUPPLIES
AND EXPENSE
29.79
.00
17.38
111.08
.00
.28
.00
1,064.93
7.03
.53
.41
36.56
296.12
282.15
111.42
149.95
26.82
$2,134.45
3RD qu
19
LABOR
3,481.00
.00
.00
673.00
.00
.00
.00
320.00
.00
.00
78.00
634.00
345.00
2,733.00
106.00
.00
29.00
$8,399.00
ARTER
74
SUPPLIES
AND EXPENSE
112.00
212.00
4.25
.00
.00
.00
2.27
.00
.00
6.71
231.38
164.55
227.00
(9.09)
.00
4.70
$955.77
LABOR
5,062.00
1,036.00
1,419.00
6,266.00
1,421.00
48.00
1,179.00
2,111.00
1.330.00
110.00
279.00
1,145.00
1,113.00
11.639.00
564.00
268.00
386.00
$35,376.00
TOTAL
SUPPLIES
AND EXPENSE
7,257.69
379.67
239.19
635.62
92.53
.62
31.06
1,073.17
16.91
.53
7.75
289.08
'524.10
1,196.37
282.71
236.09
59.90
$12,322.99
* Includes $7,162.50 of contract maintenance for cleaning the reheater section
** 50Z of total account
*** 10Z of total account
-------
TABLE NO. 3
CHEROKEE 13 SCRUBBER
OPERATINC COSTS
Operating Labor
Control Operator
Auxiliary Tender
Operating Supervision
Utilities"
Electricity
Steaa
Water
Air
Maintenance
Labor
Instrument Repair Labor
Material
ANNUAL
QUANTITY
585 Man-Hr
1.460 Maa-Ur
260 Man-Hr
23,000.000 KWH
98.600 aetrlc ton
(217,000 M Ib)
UNIT TOTAL
COST ANNUAL COST
S $
8.23/Kan-Hr* 4,800
6.31/Man-Hr« 9.200
1
8.82/Man-Hr* 2.300
i
0.006/KViH ; 138,000
1.54/merrlc ton '
(0.70/M Ib) ; 151.900
566,000 aetrlc tor. • .0066/nit-t rl,~ ton
(1,248,000 M Ib) i (O.OOJ/M Ib) 3,700
2,650 x i03 «3 >.d3/103 o5 i
! (98.900 MSCF) (0.165/KSCF) 15.500
See Table 2 35,^.00
585 Kan-Hr ?.56/Man-Hr* 4,400
i
See Table 2 12,300
i
Operating Supplies j
i
LlM
Polyethylene Balls ; i.178 M
•«* 54,000
37.0/M 43,500
i
Miscellaneous
Increase in Ash 1-andllng ,
TOTA1
»** 20.00O
695,000
X OF
TOTAL ANNUAL
OPERATING COST
1.0
1.9
0.5
27.9
30.7
0.7
.1.1
7.!
0.9
2.5
10.9
i t>.&
1
i
1
t.C
1 GO . 0
Ir.:ljde,i 26" : r ,>vr r..«iiJ
S..->t-j en 751 i-'-.-.r.c . .-.r
fSCC Eotlaate-i iSt;e L'iSi-uaBloc Stctlot)
D-10
-------
capacity. Since the scrubber does not operate all the time, either
because the unit is out of service, the unit is being fired on 100%
gas, or the scrubber itself is out of service for maintenance, a total
yearly on-line efficiency of 75% was used in computing the annual costs
for utilities. An increase in on-line efficiency of 5% would increase
the yearly utilities costs by approximately $19,000.
All unit costs for utilities were supplied by PSCC with the exception
of air costs. This value was obtained from Steams-Roger estimators
as a good approximation of air costs. Air usage includes sootblowing,
instrument, and service air.
If the scrubber is running at its full rated electrical load, the
electric power consumption is 6.39 MW which represents 4.26% of the
total #3 unit nameplate output.
3.4 Maintenance costs
All major pieces of equipment at the Cherokee station are unit coded.
Any maintenance labor or material costs which are charged against
any piece of equipment are entered on computer cards. Computer print-
outs of these charges are printed on a quarterly basis. Table 2 was
assembled from these records for the last four quarters of scrubber
operation ending with the third quarter of 1974. The four quarters
were totalled and averaged to get a yearly cost which was entered in
Table 2. For some areas which are common to all scrubbers, such as
"Piping and Valves," an estimation was made as to what percentage
should be charged to the #3 scrubber. Since the #1 scrubber was the
only other scrubber operating during this period (the #4 scrubber
came on line during the third quarter of 1974), the #3 scrubber was
charged 50% of general scrubber accounts. The maintenance charges
include payroll overhead charges.
The maintenance records do not include labor charges for instrument
repair. The results engineers at Cherokee estimate that they spend
an average of 48 hours/month on the #3 scrubber. Overhead charges
of 26% were added to the base wage rate, as was done for operating
labor.
3.5 Operating supplies
There are two major items that are included in operating supplies,
lime and polyethylene spheres.
A slurry stream is continually purged from the scrubber to keep t he
slurry concentration at a specified level. This slurry stream is
pumped to the ash disposal pond. Since the slurry has a low pH, lime
is added to the ash pond to neutralize the water overflow and make
it acceptable for release into the Platte River.
D-ll
-------
Lime charges for all three scrubbers are currently running about
$18,000/month. Since #3 scrubber contributes 31% of the total scrubber
slurry blowdown from the three scrubbers involved, 31% of the $18,0007
month was charged to it. This amounts to $5,580/month or $67,000/year.
Since start-up, the spheres which provide the contact surface area
have been replaced several times. Sometimes only individual sections
would be replaced as needed. The use of spheres of different materials
has provided different wear characteristics. The original polypropylene
spheres lasted approximately 6,000 hours of operation with a very high
breakage rate. Since the scrubber was down a little over 40% of the
time the first year, 6,000 hours was not reached until the second year
of operation. A total replacement rate of once a year was selected as
a desirable goal. This replacement rate could be achieved if the ball
wear continues to decrease.
The replacement costs are based on replacing the spheres with polyethylene
spheres at the current cost of $37/1000. If Thermal Plastic Rubber
spheres were used, the cost would be $65/1000 (see Section 4.2).
3.6 Miscellaneous
The only major miscellaneous cost item is the increased cost of ash
handling. This increased ash handling is a result of the removal of
particulate matter in the scrubber and the lime added to neutralize
the slurry. PSCC estimates that ash handling has increased approxi-
mately 10% because of the #3 scrubber. The current total ash disposal
costs are about $200,000/year. The #3 scrubber is therefore assessed
$20,000 of this cost.
D-12
-------
SECTION 4
MAJOR MAINTENANCE AND OPERATING PROBLEMS
This section discusses the major maintenance problems associated with
operating the #3 scrubber at PSCC's Cherokee plant. The source and
nature of these problems come from discussions with personnel from
PSCC. Many of the maintenance problems have been solved or minimized,
as is shown by the increase in reliability of the scrubber since the
first year. PSCC feels that this scrubber exhibited a typical opera-
tional availability curve. Initially the scrubber operated well
because of the "newness" of the equipment. Then a 8 to 9 month
period of system debugging occurred followed by a steady increase
in availability. PSCC points out, however, that each scrubber
seems to have its own unique problems.
4.1 List of major maintenance problems
4.1.1 Breakage of mobile bed contactors (plastic spheres)
4.1.2 Migration of mobile bed contactors
4.1.3 Guillotine dampers
4.1.4 Recirculation pumps
4.1.5 Reheater section
4.1.6 Rubber lined piping
4.1.7 Presaturator build-up
4.1.8 Mist eliminators
4.1.9 Stack damper interlock system
4.1.10 Recirculation system venturi flowmeters
4.1.11 Booster fan bearings
4.1.12 Weather related problems
4.2 Breakage of mobile bed contactors (plastic spheres)
PSCC considers this to be their major maintenance problem. The scrubber
is packed with 1,177,000 plastic spheres having a diameter of 3.8 cm
(1.5 inch) and weighing 5 grams each. These spheres are held in place
in the scrubber by a series of grids. The basic problem is that because
of the turbulent nature of the system, the spheres wear out or break
apart. The replacement of these spheres is a major expense item and
also causes loss of operating time. In October and November of 1973
the scrubber was down for about 11 days to replace the spheres.
In addition to replacement costs, the sphere fragments were falling
through the grids and into the recirculation pumps severly cutting
the pump rubber lining. These fragments would also pass through the
pump and plug up the nozzles in the recirculating system. This problem
has been satisfactorily resolved by placing screens in the scrubber
hoppers to keep the spheres from getting into the pump suctions. However,
D-13
-------
this creates another problem, that of screen plugging. Eventually
enough of these sphere fragments collect on the screens, plugging
the pump suctions to the point where the scrubber must be shut down
to clean the screens.
In an effort to come up with a better packing, PSCC has tested and
is still continuing to test spheres of different materials. To date
the major types of spheres they have tested are:
1. Polypropylene
2. Polyethylene
3. High density polyethylene
4. Thermal plastic rubber (TPR)
Their experiences with the four above-mentioned materials are as
follows:
1. Polypropylene - The scrubber was originally packed with
spheres of this material, however, this type of sphere
is no longer manufactured. The original cost was $32/1000
for orders of a million or more. Spheres of this material
were weak at the poles and would wear out in this area
first. The original packing lasted for approximately
6000 hours of operation with a very high breakage rate.
2. Polyethylene and High Density Polyethylene - These spheres
are the major type currently being used in the scrubber.
They currently cost $37/1000 for orders of a million or more.
They have better wear characteristics, but they are manu-
factured by joining two halves together and they have a
very high breakage rate at the seams. The half spheres
are small enough to fall through the grids and cause plug-
ging problems.
3. Thermal Plastic Rubber (TPR) - The TPR spheres are currently
being tested in the scrubber. They have a higher initial
cost of $65/1000 for orders of a million or more. Some
earlier TPR spheres that were tested would tend to dimple
at the poles, allowing them to pass through the grids,
but the newer ones being tested now are better in this
respect. The TPR spheres are to date showing good wear
characteristics.
The development of spheres with better wear and breakage characteristics
or the use of slightly heavier balls, would do a lot towards increasing
reliability and decreasing operating costs.
4.3 Migration of mobile bed contactors
A second problem with the contacting spheres is the migration of the
spheres from one section of the scrubber to another. This will occur
even if there is only room enough for one sphere at a time to pass
D-14
-------
through one of the partitions. Special care must be taken if one of
the vertical partitions should come up against a vessel entrance man-
way. The partition must extend into the portal area or the spheres
will migrate around it.
Migration of the spheres allows the gas to channel through the empty
sections and reduces contacting efficiency. If the pressure drop
across the scrubber drops below 8" W.G., it is an indication that
channeling of the gas is occurring. The scrubber is then shut down
to repair any damaged partitions, redistribute the spheres, and
replace any damaged spheres.
4.4 Guillotine dampers
The #3 Cherokee scrubber uses guillotine isolation dampers. There are
two major problems associated with these dampers. The first problem
occurs when the dampers are operated. The dampers are stopped by limit
switches. When closing, an ash build up in the duct prevents the gate
from closing completely and the lower limit switch is not contacted.
Consequently, the gate continues to try to close against the ash and
overtravels the jackscrews and shears the motor couplings. PSCC suggests
that the closing of the dampers should be controlled by both a torque
limiting coupling and a zero speed switch control scheme. That way,
if the limit switch is not reached before resistance is encountered,
the torque limiting control would prevent damage to the drive train.
The second problem is that they leak. Ash laden flue gas exits through
various seams in the gate bonnets. This ash collects in the surround-
ing areas, covering the drive train motors, gear boxes, and couplings.
This coating hinders all operational aspects of the gates and provides
an unworkable atmosphere for maintenance and operation personnel.
4.5 Recirculation pumps
There have been several problems associated with the recirculation pumps.
Originally five all rubber-lined pumps were installed. The original
pumps had problems with shaft shearing. The shafts were milled wrong
and had one stress concentration point where the shaft breakage occur-
red. A new milling procedure was used on the replacement shafts and
there have been no problems with shaft breakage since.
Secondly, the recirculation pumps have overhead motors with V-belt
drives. The original motor inboard bearings would fail if the belts
were tensioned too tight. These bearings have been replaced with a
better bearing design and there has been little problem with them
since.
Besides the above modifications to the original pumps, two other types
of pumps have been tried. One of the original pumps was removed
and two test pumps were installed. The first pump initially performed
D-15
-------
satisfactorily. The second puiap, however, performed exceptionally
well and has been in service to date with only minor maintenance
work. Its performance has been so good that PSCC is using these
pumps on its latest scrubber installation on their #4 unit.
4.6 Reheater section
The exit gases from the scrubber are directly reheated by three banks
of steam coils located just above the scrubber vessel outlet. Aux-
iliary steam from the boiler is reduced in pressure and injected into
the upper two sets of finned-tube coils. The condensate from the two
upper coils is then sub-cooled 10° F by injection through the lower
plain-tube coils. The steam coils are designed to reheat the flue
gas to 225° F.
The service life of these carbon steel reheater coils is a direct
function of the performance of the mist eliminators. If droplets
of low pH high TDS slurry get through the mist eliminator or are
re-entrained off the mist eliminator blades, corrosion and plugging
of the carbon steel tubes occur. When low pH droplets of slurry
hit the smooth carbon steel subcooling tubes (wall temperature less
than 200° F), rapid corrosion of the tubes results. When droplets
of the low pH, high TDS slurry hit the finned carbon steel condensing
coils, the water evaporates leaving an inorganic scale crystalized
around fly ash particles; this eventually plugs the fins.
Because collected droplets have to drain off the blades counter-
current to the gas flow, some re-entrainment of slurry droplets is
probably a fact of life for horizontal mounted mist eliminator blades.
If the duct section that expands into the mist eliminator section
expands at too great an angle, there is flue gas separation at the
expansion point and backflow at the edges of the mist eliminators;
as a consequence, there is a higher than design flue gas velocity
at the center of the mist eliminator bundle. These high velocities
can increase the rate of re-entrainment in the mist eliminator.
The initial installation provided a set of sootblowers below the
middle finned-tube section of coils to blow the ash off the tubes
periodically. Whereas these blowers did keep the ash blown off
the leading edges of the middle finned-tube section, they were
ineffective with the remainder of finned-tubes. In April and May
of 1973 the scrubber was taken out of service in order to completely
remove the coils and clean them with high pressure jets. The plug-
gage problem continued and two steps were taken to more efficiently
clean the tubes. First, a second set of sootblowers was added just
below the upper layer of finned-tubes, and second, an operational
change was instituted. Whenever the unit was being fired on 100%
gas, the gas flow to the scrubber was shut off and the reheater
was left on. This tended to bake the ash onto the coils and dry the
scale. This dryer scale could then be blown off by the sootblowers
more easily. These changes appeared very promising; however, just
D-16
-------
recently major tube failure and excessive corrosion has rendered
this reheater virtually inoperative. PSCC is now planning to install
a protective coating in the outlet ductwork to the stack to prevent
corrosive attack of the outlet breeching. PSCC is also investigating
the installation of an indirect reheat system similar to that now
installed on the Cherokee #4 scrubber. PSCC feels that the indirect
reheat system will be the only acceptable long range solution.
4.7 Rubber lined piping
Since there is some absorption of S(>2 from the flue gas, the recircu-
lating liquid streams are low in pH and are therefore corrosive to
most types of metals. This necessitates the use of rubber lined pipe
and 316L stainless steel valves. However, the collection of the fly
ash produces a slurry which is also erosive when pumped. If care is
not taken when the rubber lining is applied, it will be eroded away
and the pipe will then be exposed to failure by corrosion.
The recirculation line splits on the discharge of the recirculation
pumps prior to entering the scrubber. The section where the pipe Y's
is particularly vulnerable to problems with rubber linings. The orig-
inal piping was lapped wrong in this area and the pipe failed and had
to be replaced.
In January and February of 1973 just a few months after initial start-up,
the scrubber was down for 32 days to inspect and repair piping.
4.8 Presaturator build-up
The presaturator section cools the hot flue gas to near the saturation
temperature of the gas (approximately 125° F) by use of water sprays.
Originally the spray nozzles were oriented vertically. There was a
build-up of soft solids in the area of the wet-dry interface. This
accumulation of solids would eventually slough off and fall into the
scrubber hoppers and plug the screens. There were also times when the
water would spray back into the fans. This problem was corrected by
repositioning the nozzles so that they pointed 45° into the scrubber.
This moved the wet-dry interface further downstream and has prevented
water from entering into the fans.
4.9 Mist eliminators
The mist eliminators are constructed of fiberglass reinforced plastic
(FRP) blades. As the scrubber comes up on load, it is thought that
these blades may shudder to some extent, thereby increasing the pressure
drop across them restricting the gas flow. The scrubber has experienced
as high as 4-5" W.G. drop across the mist eliminators. In other scrubber
installations PSCC uses stainless steel blades in their mist eliminators,
and the pressure drops are not as great. Although they have not replaced
the FRP blades in the #3 scrubber as of yet, they do feel that stainless
steel blades are better.
D-17
-------
4.10 Stack damper interlock system
The flue gas from the #3 unit passes through a mechanical collector,
an electrostatic precipitator, the boiler I.D. fans and into the scrubber
booster fans. There is also a bypass duct which goes directly from
the I.D. fans into the stack. There are guillotine isolation dampers
at the discharge of each booster fan and a stack damper in the bypass
duct. This allows for the following conditions:
1. If the scrubber is off-line it can be isolated from the
boiler and the flue gas bypassed to the stack. There-
fore, the scrubber can be taken off-line for repairs with-
out causing a boiler outage.
2. If the flue gas flow is too high to the scrubber, some of
it can be bypassed to the stack.
3. If the flue gas flow is too low to the scrubber, the stack
damper will open and allow some recirculation of flue gas
back to the scrubber to assure the necessary gas velocity
in the scrubber.
Originally the stack damper interlock system did not respond quickly
enough. When an upset condition occurred which would trip the scrubber,
the guillotine dampers which isolate the scrubber would close and the
stack damper would start to open. However, since the stack damper was
slow to respond, the flue gas would back pressure the boiler and cause
it to trip.
In order to get the stack damper to respond faster to a scrubber upset,
a manual push button control was installed in the control room. The
control operator is now able to activate the stack damper immediately
whenever necessary.
Also, the source of instrument air was changed for the stack damper
control system. Originally the stack damper control air came from
the same point that the scrubber control air was tied into the main
air supply. If instrument air was lost to the scrubber, the damper
would be shut. The stack damper control air was changed so that it
is tied into the boiler I.D. instrument air supply. This insures
that the stack damper cannot be inoperable due to loss of instrument
air while the boiler is still on line.
PSCC also had problems with dampers mechanically freezing up. This
problem can be eliminated by frequent exercising and by complete
cold testing prior to the initial scrubber startup.
4.11 Recirculation system venturi flowmeter
The recirculation lines were originally equipped with venturi flowmeters.
The venturi flow section was made of fiberglass, the throat was made of
alloy 20 S.S., and the flanges were made of carbon steel. Low pH
D-18
-------
recirculated slurry accumulated on the high pressure leg sample port
in the area between the throat and the pipe. This corroded through
the carbon steel flanges. The meters have been taken out and PSCC
has plotted a curve of the recirculation pump motor current versus
recirculation flow. This gives them a fairly accurate estimation
of the recirculating flow without actual flow measurement.
Two other possible solutions would be to replace the carbon steel
flanges with flanges of more acid resistant material, or to use
magnetic flow meters for flow measurement.
4.12 Booster fan bearings
The bearings on the booster fans are a minor maintenance item. It is
impossible to prevent some small build-up of ash on the fan blades
even though the blades are cleaned with soot blowing air. This build-up
causes the fan to be slightly imbalanced and wears the bearing out
faster than normal. This problem is minimized if care is taken to
insure continuous operation of the fan soot blowers.
4.13 Weather related problems
Freezing lines have always been a problem with the scrubber operation
during extreme cold weather because of the large number of water and
slurry streams. Special care must be taken to make sure all lines
(including control air lines) are insulated and heat traced. Also,
lines should be drained whenever possible when the scrubber is shut
down for extended periods of time during cold weather. Most of the
down time during the first two months of operation can be attributed to
freezing of control lines and process lines. In December of 1972,
a malfunction of the booster fan controls caused a quick shutdown
during unseasonably cold weather. There was not time for proper
drainage of all lines and half of the month was lost while repairs
were made to piping, valves, and the Bailey control system components
which were damaged by the freezing weather.
An alternate solution to protect against cold weather problems is
to enclose the entire scrubber installation in a weather-proof build-
ing. This was done when the Cherokee #4 scrubber was installed.
However, there is one major problem associated with doing this; that
is the possibility of filling the enclosure with raw flue gas.
D-19
-------
SECTION 5
SCRUBBER RELIABILITY
This section reviews the operating reliability of the #3 scrubber
from start-up in October, 1972 to the end of November, 1974. The
data was obtained from the availability log summary sheets which
are kept each month by PSCC. These sheets keep a record of when
each section of the scrubber is on or off line. They also record
whenever the boiler is out of service or burning 100% gas.
5.1 Areas covered in the reliability study
5.1.1 Breakdown of hours at different % capacity
5.1.2 Accumulative % available to date
5.1.3 Accumulative 7, available previous 12 months
5.2 Breakdown of hours at different % capacity
The #3 scrubber is designed with three separate sections which are
labeled A, B and C. Sections A and C have one recirculation pump
each and are each designed to each handle 207« of the total capacity
of the scrubber. Section B has three recirculation pumps and is designed
to handle 607o of the total capacity. It is possible for any combination
of the three sections to be running at any time. Therefore, it is
possible to run at every increment of 207. of full capacity with the
following combination.
SECTIONS ON LINE SECTIONS OFF LINE % OF CAPACITY
A + B + C - 100
A + B C 80
B + C A 80
B A -I- C 60
A + C B 40
A B + C 20
C A + B 20
A + B + C 0
PSCC's reliability log gives a record of down time for each section
along with the reason the section was down. By using the above com-
binations, it was possible to show how many hours each month the
scrubber ran at various capacities. This breakdown is presented in
Table 4. Also included in the table is a record of the hours the
boiler operated each month, and the hours that the boiler was burn-
ing 1007o gas. Table 5 gives a brief description of the major main-
tenance items which caused the scrubber to be down each month. An
explanation of these maintenance problems is given in Section 4.
D-20
-------
TABLE NO. 4
CHEROKEE *3 SCRUBBER
BREAKDOWN OF HOURS AT DIFFERENT Z CAPACITIES
MOUTH/YEAR
Oct. - 72
Nov. -
Dec. -
Jan. -
Fab. -
Mar. •
Apr. -
May -
Jun. -
Jul. -
Aug. -
S.p. -
Oct. -
Nov. -
Dec. -
Jan. -
Feb. -
Mar. -
Apr. -
May -
Jun. -
Jul. -
Aug. -
Sap. -
Oct. -
Nov. -
TOTAL
X
72
72
73
73
73
73
73
73
73
73
73
73
73
73
74
74
74
74
74
74
74
74
74
74
74
n
52
625
438
298
547
360
235
744
112
1
3
57
78
178
0
0
0
70
0
0
0
0
10
27
6
5
3.846
27.1
20*
2
0
0
0
0
0
0
0
0
0
0
0
0
0
0
17
0
0
0
0
0
0
0
0
0
6
25
0.2
407.
107
0
42
0
0
0
11
0
1
0
0
0
0
0
1
0
0
0
0
0
0
0
0
0
1
3
166
1.2
60t
0
0
4
2
0
0
0
0
0
0
0
37
0
32
0
0
0
5
0
0
0
2
0
0
0
0
82
0.6
901
21
42
0
4
53
110
0
0
4
35
5
356
2
110
5
547
0
21
184
0
0
34
0
1
22
10
1,566
11.0
100%
136
53
209
440
72
274
410
0
518
708
736
270
664
400
676
175
35
65
514
235
48
527
8
0
669
645
8,487
59.9
BOILER
318
720
693
744
672
744
656
744
635
744
744
720
744
720
682
739
35
161
698
235
48
563
18
28
698
(,69
14,172
100.0
BOILER
(1007. CAS)
458
672
181
726
692
2,729
D-21
-------
TABLE NO. 5
CHEROKEE 13 SCRUBBER
LIST OF MAJOR MAINTENANCE ITEMS WHICH
RESULTED IN SCRUBBER DOWN TIME
Month/Year Maintenance Items
Oct-72 Reclrculation pump (B-section), booster fan trip
Nov-72 Freeze problems, control failures
Dec-72 Major freeze damage to process and control lines,
plugging (B-section)
Jan-73 Victaulic coupling and pipe failures
Feb-73 Victaulic coupling and pipe inspection and repair,
reheater tube leak (C-section)
Mar-73 Slurry drawoff line failed, demister holddowns
replaced, recirculation pump and inlet gate drive
mechanism (C-section)
Apr-73 Reheater steam leak
May-73 Remove, repair and clean reheaters
Jun-73 Steam and air leaks, booster fan control linkage,
demister repair
Jul-73 Recirculation line and flow nozzle (A-section)
Aug-73 Tie in of power for #4 scrubber, piping repair
(A-section)
Sept-73 Recirculation pump (A-section), repair B3"Y" piping
Oct-73 Ball maintenance
Nov-73 Ball maintenance, plugged reheater (C-section)
Dec-73 Minor steam leaks
Jan-74 Recirculation elbow leak (A-section), recirculation
pump (C-section), control failures (B-section)
Feb-74 Boiler off stream
Mar-74 Recirculation block valve, booster fan bearings
Apr-74 Recirculation pump liner (C-section)
May-74 No down time
Jun-74 No down time
Jul-74 Recirculation pump (A-section), "Y" piping leak
(C-section)
Aug-74 Start-up problems
Sept-74 Vertical grid replacement
Oct-74 Booster fan vibration
Nov-74 "Y" piping (A-section), control failures, booster fan
bearing (A-section), discharge block valve (B-section),
reheater blowdown (C-section)
D-22
-------
5.3 Accumulative % available to date
For this study, availability of the scrubber was defined as:
A '1 b'l't = fr°urs °f scrubber operation*- hours boiler was burning 100% gas
hours of boiler operation - hours boiler was burning 100% gas
The reason that the hours the boiler was burning 100% gas was subtracted
from the total hours of scrubber and boiler operation is because the
scrubber is normally either left running with water systems operating
only or completely shut down during periods of 1007» gas burning operation.
It is interesting to note that the scrubber is out of service a majority
of the time during August and September of 1974 when the unit returned to
mixed fuel burning. The reason for this is that after long periods of
idleness, due to either maintenance or 1007» gas burning, the scrubber
usually experiences minor start-up problems. When start-up troubles
with the scrubber were encountered, every effort was made to use any
available gas on the unit. Consequently the scrubber had a poor per-
centage availability for the months involved, but the overall avail-
ability was not effected very much.
Table 6 was constructed from the data in Table 4. In Table 6 the %
available each month, accumulative % available to date and accumulative
7o available for the previous 12 months are calculated.
These values are given for two capacity levels; 10070 of capacity and
807o of capacity or greater. The reason that both capacity levels are
calculated can be best seen from Table 4. There is a significant amount
of time that the scrubber operates at 807, of capacity. For example,
in January of 1974, although the scrubber only operated at 10070 of
capacity for 175 hours, it did operate at 807o of capacity for 547
hours. Although the scrubber is not treating all of the boiler flue
gas, it is felt that some credit should be given the scrubber for
handling most of the flue gas. In most cases running at 807=, of capacity
will probably allow PSCC to meet particulate emission standards.
The accumulative °L availability to date reflects the total hours of
scrubber operation since start-up. This value is plotted by month
in Figure 2. This figure shows that after an initial drop, the avail-
ability of the scrubber has been increasing steadily. This is typical
of other PSCC scrubber operations. The initial drop is attributed to
the many minor design problems which arise soon after start-up. The
Hours of scrubber operation is related directly to the time the
boiler was operating.
D-Z3
-------
TABLE NO. 6
CHEROKEE *3 SCRUBBER
AVAILABILITY SUMMARY
MDtmi/rEAR
Oct.
•ov.
Dec.
J«n.
Feb.
H»r.
Apr.
»*y
JOB.
Jul.
Au,.
S.p.
Oct.
•ov.
DBC.
Jut.
Feb.
Mr.
Apr.
»«7
Jim.
Jol.
Ao«.
S«p.
Oct.
HOT.
- 72
- 72
- 72
- 73
- 73
- 73
- 73
- 73
- 73
- 73
- 73
- 73
- 73
- 73
- 73
- 74
- 74
- 74
- 74
- 74
- 74
- 74
- 74
- 74
- 74
• 74
TOTAL
Honts
BOILER
OK*
318
720
693
744
672
74i
656
74i
635
744
744
720
744
720
682
739
35
161
698
235
48
563
18
28
698
669
lOOt CAPACITY
TOTAL
HOURS
136
53
209
440
72
274
410
0
518
708
736
270
664
400
676
175
35
65
514
235
48
527
8
0
669
645
ACCUMULATIVE
I
T AVAILABLE
AVAILABLE TO DATE
42.8
7.4
30.2
59.1
10.7
36.8
62.5
0.0
81.6
95.2
98.9
37.5
89.2
55.6
99.1
23.7
100.0
40.4
73.6
100.0
100.0
93.6
44.4
0.0
95.8
96.4
42.8
18.2
23.0
33.9
28.9
30.4
35.1
30.1
35.6
42.3
48.0
47.0
50.6
50.9
54.1
52.1
52.3
52.1
53.3
54.2
54.4
56.2
56.1
56.0
58.1
59.9
ACCUMULATIVE
Z AVAILABLE
PREVIOUS
12 MONTHS
42.8
18.2
23.0
33.9
28.9
30.4
35.1
30.1
35.6
42.3
48.0
47.0
50.9
54.9
60.5
57.4
61.5
63.6
64.6
72.9
72.2
71.4
67.4
71.7
72.5
78.6
801 CAPACITY
TOTAL
HOURS
157
95
209
444
125
384
410
0
522
743
741
626
666
510
681
722
35
86
698
235
48
561
8
1
691
655
*
AVAILABLE
49.4
13.2
30.2
59.7
18.6
51.6
62.5
0.0
82.2
99.9
99.6
86.9
89.5
70.8
99.9
97.7
100.0
53.4
100.0
100.0
100.0
99.6
44.4
3.5
99.0
97.9
ACCUMULATIVE
I
AVAILABLE
TO DATE
49.4
24.3
26.6
36.6
32.7
36.3
40.1
34.5
39.6
46.3
51.7
54.8
57.7
58.7
61.4
63.8
64.0
63.8
65.9
66.6
66.7
68.2
68.1
68.0
69.6
70.9
ACCUMULATIVK
Z AVAILABLE
PREVIOUS
12 MONTHS
49,4
24.3
26.6
36.6
32.7
36.3
40.1
34.5
39.6
46.3
51.7
54.8
58.0
62.9
68.5
71.7
76.4
78.4
81.9
91.4
92.4
92.1
90.9
91.0
92.5
96.7
* Exclud** TlM Unit W*« On 1001 G*«.
D-24
-------
70 •
(Ji
„,
•1
I
I
60
40-
M« CAPACITY
20
FIGURE 2
CHEROKEE NO. 3 SCRUBBER
ACCUMULATIVE X AVAILABLE TO DATE BY MONTH
10 -
§ 1 g 1
1972
I 5
5 i 8 3
|
i I \
|
1973
m«
MONTH
-------
following increase in availability is attributed to the solving of
these problems and the increased operating knowledge which is gained
through operating experience.
As of November 30, 1974, the scrubber had operated at 100% of capacity
59.97= of the time and at 807o of capacity or greater 70.97=, of the time.
5.4 Accumulative % available previous 12 months
In order to more clearly see the increase in availability with time,
after the first year when each new month is added to the log, only the
previous 12 months availability is calculated. This value is tabulated
by month in Table 6 and plotted in Figure 3. Looking at the last month
tabulated (November, 1974), reveals that the scrubber operated at 1007»
of capacity 78.67. of time and at 807. of capacity or greater 96.77o of
the time during the previous year. The figure also shows that the
scrubber has been operating at 807, of capacity or greater with over
907. availability since May of 1973.
D-26
-------
BO-
I "
f •
10
FIGURE 3
CHEROKEE NO. 3 SCRUBBER
ACCUMULATIVE % AVAILABLE PREVIOUS 12 MONTHS BY MONTH
i
1B72
*
1C
I
* 8
I
<
|
i
1071
1974
MONTH
-------
SECTION 6
FEASIBILITY AND COST OF A
"PROBLEM FREE" SCRUBBER SYSTEM
The original objective for this part of this study was to prepare a
conceptual design of and a feasibility-level cost estimate for a
"problem free" scrubber system. As the work progressed, it became
obvious that "problem free" is difficult to define. From a strict
definition standpoint there is not and probably never will be a totally
"problem free" scrubber system. In any system made up of a variety of
operating mechanical components (pumps, fans, valves, scrubbers, etc.)
there are—over the life of the system—failures, breakdowns, overhauls,
replacements, etc., of the mechanical components; such things frequently
cause shutdowns and such things, although routine, are considered by
many to be "problems."
If a less restrictive definition is allowed, "problem free" still
means different things to different people: to a maintenance super-
intendent it means minimum maintenance attention and cost; to an
enforcement officer it means maximum on-line time; to a corporate
executive it probably means minimum capital cost; and to an operating
superintendent it means minimum operating attention.
From the broad definition standpoint, "problem free" becomes some
optimum balance between availability, capital cost and operating/main-
tenance attention. This optimum balance is not constant; it will
change from plant location to location depending on such things as
space availability, regulations, cost of capital, availability of
trained personnel, etc.
Many ways of improving scrubber system availability and reducing
operating/maintenance attention were studied. The problems that
were investigated fall into several different categories.
1. Problems which require further research and development.
An example is the development of a mobile contactor with
better breakage/abrasion characteristics. The develop-
ment of a better contactor would result in less downtime
and lower operating costs by increasing the interval be-
tween contactor replacement, and increasing the interval
between recirculation pump suction screen cleanings.
Another item which still requires more development work is
the manufacture of a better isolation gate. The large
size of the ducts needed to handle the amount of flue gas
from a typical power plant, necessitates the use of large
isolation gates. Their large size makes the gates subject
D-28
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to mechanical failures such as jacking mechanism problems
associated with proper monitoring of full open and close
limits, ash buildup, and corrosion.
2. As experience is gained from operations, improvements are
made in the design of various individual scrubber system
components. Recirculation pumps are an example. Many
pump vendors are producing pumps which can handle the low
pH scrubber slurry with better performance than earlier
designs. Knowledge of this experience with various pumps
is needed to select the right pump for scrubber application.
The same holds true for lining materials and other materials
of construction for valves, piping, nozzles, etc.
Since "problem free" is a subjective term and, as such, difficult to
precisely define, it was decided that the objectives of this part of
the study would be limited to investigating ways of shifting the re-
liability-capital cost-operating/maintenance attention balance to
improve reliability and reduce operating/maintenance attention at
the expense of greater capital cost. Before discussing specific
items, there are two other points that should be made.
1. If there is sufficient space, availability can be improved
by spending additional money to provide redundant stand-by
modules. Thus, if one module is down for repairs or main-
tenance, the remaining modules can carry the full flue gas
load. The expenditure of additional money does not diminish
the operating/maintenance "problems," it just provides spare
equipment to be put in service to maintain system availability
when an operating module is shut down for repairs or mainten-
ance.
2. In the real world, engineered solutions to "problems" do not
always necessarily diminish or solve a "problem." For instance,
a recirculation pump that looks good in other similar services,
may not perform up to expectations in the scrubber system. A
spherical contactor material that looks good in laboratory
tests may not look as good in actual full-scale plant tests.
This is to say that the engineered improvements discussed in
this section should increase availability and decrease opera-
ting/maintenance attention but that the success of these fixes
cannot really be evaluated until the modifications have been
made and tested.
3. There are some specific, definable changes to the basic
scrubber design which would significantly improve avail-
ability. These changes are discussed and priced out in
the following text.
D-29
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a. Addition of a Spare Section
As mentioned before, availability can be improved by
adding an extra scrubber section which acts as a spare
whenever another section is out of service. As can be
seen from Table 6 and Figure 2 in Section 5, the differ-
ence in availability between operating at 100% capacity
and 80% capacity varies by 10-20% for the last year or
so of operation. If a spare section had been available,
much of that difference might have been eliminated. The
addition of a redundant section would not solve any main-
tenance problems; in fact, it would increase maintenance
costs because there would be more equipment to maintain.
If an extra scrubber section were designed into the
original scrubber system, the optimum design would prob-
ably be based on four independent 33 1/3% capacity
sections. This approach to increasing availability is
very costly. The addition of an extra section would
require duplication of all related equipment. It is
estimated that a scrubber system with 4 x 33 1/3%
sections would cost about $1,200,000 more than the 1975
capital cost for the existing Cherokee #3 scrubber system.
b. Indirect Reheat
The major possible change in design for the present
system concerns the reheat system. In the present
direct reheat system, the reheat coils are located in
the flue gas duct and as a result the coils are subject
to plugging and corrosion. The use of an indirect re-
heat system is considered more reliable although more
expensive. With an indirect reheat system outside air
is heated and mixed with the flue gas as it leaves the
scrubber.
This requires extra reheat fans, an extra damper, and
extra ductwork for each scrubber section. Although
the unit cost of reheat transfer surface is lower for
indirect reheat, more surface is required because of
the extra volume of air introduced. Similarly, the
direct reheat system has sootblowers to clean the coils
which would not be necessary with an indirect system.
Taking all the above things into consideration, it is
estimated that an indirect reheat system—designed into
the original scrubber system—would cost approximately
$200,000 more than a direct reheat system and would
thus add $200,000 to the total 1975 scrubber system
cost. It should be noted that the actual cost of a
retrofit indirect reheat system has been estimated at
almost $600,000.
D-30
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The use of an indirect reheat system also results in
slightly higher operating costs. There would be additional
steam requirements because of the increased volume to
be heated brought about by the introduction of the reheat
air and additional electrical requirements for the reheat
air fans. It is estimated that this would add about
$35,000/year in utility costs.
Indirect reheat is in use on the Cherokee #4 scrubber.
Some problems are being experienced with condensation
of the flue gas in the stack, however, this is a result
of the reheat fans not being able to supply enough re-
heat air to maintain a sufficient temperature in the
stack. It appears that if the fan capacity is increased,
the indirect reheat system will perform satisfactorily.
c. Scrubber Enclosure
Housing the scrubber in a heated, ventilated enclosure
would eliminate many of the problems of freeze-ups
during cold weather. The cost of adding such an enclosure
including metal sidings, fans, heating and cooling systems,
and electrical work would be approximately $90,000.
d. Miscellaneous Changes
There are many smaller changes which could add to the
reliability of the scrubber operation. The last type
of recirculation pump tested by PSCC is showing superior
performance as far as maintenance problems are concerned.
These pumps are more expensive and if used would add
approximately $45,000 to the pump costs.
The use of magnetic flow meters instead of venturi
flow meters would give better recirculation flow measure-
ments and would add another $15,000.
It is also recommended that the outlet duct be coated
to reduce the chance of corrosion if there is a loss
of the reheat system. This would add another $20,000
to the scrubber costs.
In order to more fully understand the economic effect on any changes
to the design of the present scrubber, it is necessary to update the
cost of the scrubber. Using the latest Chemical Engineering Plant
Cost Index values ("Chemical Engineering," April 14, 1975) of 137.2
for 1972 and 179.9 for February, 1975, an estimated 1975 cost for an
identical scrubber would be approximately $5,800,000. This represents
an increase of $1,400,000 over the original cost of $4,400,000 reported
in Section 2.
D-31
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If all the above changes were made in the redesign of the existing
scrubber, it is quite conceivable that 90 + % scrubber availability
could be obtained. The system would still have the normal mainten-
ance requirements, possibly even greater than with regular power
plant equipment.
The list below summarizes the changes mentioned and costs involved.
Estimated
Availability
Identical Scrubber (1975) $5,800,000 60-70%
Extra 33 1/3 Capacity Section 1,200,000 +10-15%
Indirect Reheat, incremental 200,000
Scrubber Enclosure 90,000 + 5-10%
Miscellaneous Changes 80,000
$7,370,000 85-95%
This capital cost of $7,370,000 figures out to be $49/KW for a 150 MW
unit as compared to the original $29/KW.
In closing, it should be pointed out that one of the most important
aspects of increasing the reliability of the scrubber operation is
the willingness of the operating and maintenance personnel to deal
with the many scrubber system problems that arise. The attitude at
PSCC is that they are committed to the existing scrubbers at Cherokee,
and they will try to do everything necessary to keep them on line.
This attitude is reflected in the increased reliability of the system
since the scrubbers have started to operate.
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TECHNICAL REPORT DATA
(Please read Inziructions on the reverse before completing)
1. REPORT NO.
EPA-600/2-75-074
2.
3. RECIPIENT'S ACCESSION-NO.
4. TITLd AT.'3 C'JBTITLE
Evaluation of a Particulate Scrubber on a Coal-Fired
Utility Boiler
5. REPORT DATE
November T975
6. PERFORMING ORGANIZATION CODE
7 AUTHORED. S.Ensor, B.S.Jackson, S.Calvert, C.Lake,
D. V.Wallon, R.E.Nilan, K.S.Campbell, T.A. Cahill,
and R. G. Flocchini .
8. PERFORMING ORGANIZATION REPORT NO.
MRI 75 FR-1352
9. PERFORMING OR9ANIZATION NAME AND ADDRESS
Meteorology Research, Inc.
464 West Woodbury Road
Altadena, California 91001
10. PROGRAM ELEMENT NO.
1AB012: RQAP 21ADL-092
11. CONTRACT/GRANT NO.
68-02-1802
12. SPONSORING AGENCY NAME AND ADDRESS
EPA, Office of Research and Development
Industrial Environmental Research Laboratory
Research Triangle Park, NC 27711
13. TYPE OF REPORT ANt
Final; 6/74-6/75
ND PERIOD COVERED
14. SPONSORING AGENCY CODE
15. SUPPLEMENTARY NOTES
report gives results of a performance test and engineering analysis of
a mobile-bed scrubber on a full-scale coal-fired utility boiler. The scrubber nomin-
ally operated at the design particulate removal efficiency of 95%, but the concentra-
tion of submicron particles was greatly influenced by mist entrainment. The entrain-
ment resulted in a difference of aerosol penetration through the scrubber as a func-
tion of elemental composition and outlet submicron particle concentration indepen-
dent of pressure drop through the scrubber. The variable concentration of submi-
cron entrained particles made the application of the penetration data as a function of
particle size to development of performance models unfeasible. The engineering
analysis showed that the 1972-installed cost was S"29/kw and the annual operating
cost is 0. 5 mills/kwh (75% availability). An initial decline in scrubber availability
after startup resulted from now-corrected minor design problems. Steadily impro-
ving reliability is attributed to the utility's providing maintenance and solving oper-
ating problems.
KEY WORDS AND DOCUME NT. AN AL YSIS
DESCRIPTORS
Air Pollution
Aerosols
S crubbers
Boilers
Coal
Combustion
Utilities
b.IDENTIFIERS/OPEN ENDED TERMS
Air Pollution Control
Stationary Sources
Particulate
. COSATI Field/Group
13 B
07D
07A
13A
2 ID
2 IB
13. DISTRIBUTION STATEMENT
Unlimited
_
EPA Form 2220-1 (9-73)
19. SECURITY CLASS
Unclassified
20. SECURITY CLASS (This page)
Unclassified
22. PRICE
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