EPA-BOO/2-76-036k
February 1976 Environmental Protection Technology Series
DESIGN AND OPERATING PARAMETERS
FOR EMISSION CONTROL STUDIES:
ASARCO, Tacoma, Copper Smelter
Industrial Environmental Laboratory
Offiee of Research and Development
U.S.
Research Triangle Put, 27711
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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 ano 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.
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 policy of the Agency, nor does mention of trade
names or commercial products constitute endorsement or
recommendation for use.
This document is available to the public through the National Technical Informa-
tion Service,. Springfield, Virginia 22161-
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EPA-600/2-76-036k
February 1976
DESIGN AND OPERATING PARAMETERS
FOR EMISSION CONTROL STUDIES:
ASARCO, TACOMA, COPPER SMELTER
by
I. 0. Welsenberg and J. C. Seme
Pacific Environmental Services, Inc.
1930 14th Street
Santa Monica, California 90404
Contract No. 68-02-1405, Task 5
ROAP No. 21ADC-Q61
Program Element No, 1AB013
EPA Project Officer; R. D, Rovang
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
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TABLE OF CONTENTS
A. INTRODUCTION AND SUMMARY 1
B. PLANT LOCATION, ACCESS AND OVERALL GENERAL ARRANGEMENT,.. I
C. PROCESS DESCRIPTION 7
D. EMITTING EQUIPMENT 10
a. Multi-Hearth Roasters 10
b. Reverberatory Furnaces , 11
c. Converters 12
d. Arsenic Circuit 12
e. Other Emitting Equipment 13
E. EXISTING CONTROL EQUIPMENT.... 13
F. GAS SYSTEM DUCTWORK 15
G. SULFER BALANCE AND GAS COMPOSITION AT SYSTEM EXIT 16
H. GAS CHARACTERISTIC VARIATION. 18
I. STACK DESCRIPTION. . , 28
J. PRESENT TECHNIQUE FOR SOLID WASTE HANDLING..... 23
K. FOOTING AID STRUCTURAL REQUIREMENTS ,,,.,,.,.. 28
L. EXISTING AND POTENTIALLY AVAILABLE UTILITIES 23
M. POTENTIAL NEW CONTROL EQUIPMENT INSTALLATION •PROBLEMS.... 29
REFERENCES , 30
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LIST'OF'FIGURES
1. LAND CONTOUR MAP OF SMELTER AREA. 2
2. ASARCO TACOMA PLANT 3
3. SMELTER GENERAL ARRANGEMENT 4
4. GAS SYSTEM DUCTWORK . 5
5. PROCESS FLOW SHEET .... 8
6. MASS DISTRIBUTION OF PARTICLES 21
7. MASS DISTRIBUTION OF PARTICLES 22
8. ASARCO-TACOMA CONVERTER OPERATION SULFUR BALANCE 23
LIST'OF TABLES
1. ASARCO-TACOMA AVERAGE SULFUR BALANCE SUMMARY 17
2. TACOMA SMELTER EMISSIONS ESTIMATES 19
3. LOW LEVEL EMISSION SOURCES AND CONTROL TECHNIQUES ,, 20
4. 45-MINUTE SAMPLING (3 DROPS) 25
5. REVERBERATORY FURNACE SULFUR ELIMINATION AS A FUNCTION
OF CHARGE RATE 26
ii
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A. INTRODUCTION MB SUMMARY
The purpose of this report Is to present background design
data on the ASARCO Incorporated Smelter at Tacoma, Washington in
sufficient detail to allow air pollution control system
engineering studies to be conducted. These studies are
primarily concerned with lean S0« streams that are currently not
being captured.
Physical layout of the smelter and surrounding area
along with existing smelter and control equipment is presented.
Ductwork that would be considered for future system tie-in
is defined. Emissions from operating equipment, gas flow rates,
temperatures, sulfur balance and process flow sheet are
included. Utilities, stack dimensions, footing requirements,
and solid waste handling are defined. Available area for new
control equipment, gas characteristic variation and potential
new control equipment installation problems are discussed.
The major uncontrolled sources of SO- at this smelter
•£*
are the reverberatory furnaces and the roasters. Available
space for installation of new equipment is limited, A DMA
SOT concentration system producing liquid SO- and a sulfuric
acid plant are used to control S0~ from converter off gas.
B. PLANT LOCATION, ACCESS AND OVERALL GENERAL ARRANGEMENT
The ASARCO Smelter is located at the edge of Puget
Sound in the towns of Tacoma, and Ruston, Washington. An enlargement
of the USGS map, showing land contours of the immediate area is
presented in Figure 1. Design altitude for the plant is sea
level with latitude 47° 18' and longitude 122° 30'.
Overall plant view is shown as an artist's sketch in
Figure 2. Smelter general arrangement is shown in Figure 3.
A schematic showing relative location of the major emitting
-1-
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\
Pol
\
SCALE 1:24000
o
1000 JOOO 3000 4000
_TE~--=
.8 0
6000 TOW FEET
] KILOMETER
/ i • /
"^ i
x^/ ]7°
^ / "^-f-y-
" i* *•" ^
I */ r
• \°*
i j j
D A L C 0
PA S S A G B
PIERCE i
-------
ASARCO TACOIIA PLAI1T
1MWN STACK
2.CASTIN6 FURNACE STACK
FURNACE
fCOIWERTDR BUILDING
5a ARSENIC FLAWT ^.ARSENIC ROASTERS a ARSENIC
6a NORTH AhDDE STACK b. SOUTH ANODE STACK
t ELECTKOLYFE WIFICATiCW PLANT
8 ROASTER SUILP1M-
d. METALLIC ARSENIC PLAPf
Figure 2
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Figure 3. SMELTER GENERAL ARRANGEMENT
(Located in Pocket Inside of Back Cover)
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Outlet Sampling Port
H Cottrell
Inlet Sampling Port
4 i 3 | 2 I j1 Waste Heat Boilers
„ . . . . 280 tcl "
io liuid ' Spr
FLUE DIHEHSIONS
Flue
No. 1 Brick Flue
(A-B)
No. 2 Brick Flue
CC-W
Junction Tower (E)
Reverb Flue
(G-H)
Eoaster Building Flue
d-J)
,,„_, *-
L
450'
550'
26'
165-10"
120'
H
24'
24'
43'-4"
20'-6"
12*
W
20'
20'
18'
27"
12'-1" !
|
Note: Roasters 1-6 10,000 SCFM/Roaster
Roaster 7-10 15,000 SCFM/Raaster
x Denotes Water Sprays
GAS SYSTEM DUCTWORK
ASARCO /Tacoma Branch
prepared July, 1975
PACIFIC ENVIRONMENTAL SERVICES
Figure
-------
equipment with connecting duct work is given in Figure 4.
The primary particulate emission sources are the crushing and
screening operations, the roasters, the reverberatory furnaces and
converters. The primary sources of sulfur dioxide are the
roasters, reverberatory furnaces and the converters.
This plant, from a system and equipment standpoint,
is one of the most complicated copper smelters in the United
States. It not only includes the conventional copper roasters,
reverberatory furnaces and converters, but also additional
arsenic ore processing equipment and sulfuric acid plant and
a liquid SO,, plant for SO™ control and other refinery equipment
for producing nickel sulfate, dore and sodium selenite products.
There are ten multi-hearth roasters, two reverberatory furnaces,
four converters, and arsenic trioxide and a metallic .arsenic
plant.
The smelter portion of the plant consists, of the coarse
ore and concentrate handling and crushing equipment, ten
Herreshoff roasters, two reverberatory furnaces, four conver-
ters, and three anode furnaces. Arsenic processing equipment con-
sists of six Godfrey roasters (four usable), arsenic
trioxide settling kitchens, arsenic trioxide storage and a
metallic arsenic plant. This smelter has extensive varied
equipment, primarily to handle a wide range of ore types
since it is a custom smelter.
The pollution control equipment consists of five cyclones
for the ore handling equipment along with coolers, spray chambers
and precipitators for conditioning the converter and roaster
gases going to the sulfuric acid plant and the liquid SO- plant.
All tail gases from the acid plant and liquid SO plant go
to the stack.
The gases from the roasters and reverberatory furnace pass through
electrostatic precipitators before going to the main stack.
-6-
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Figure 3 showing the overall plant arrangement indicates that
there is relatively little available area for Installation of con-
trol equipment. There is a possibility of the use of the Tacoma
Tide Lands area on the easterly side of the smelter, and some
smaller areas adjacent to existing equipment. The 50" x 100'
nickel plant will be torn down in the near future and this site
could also be used for new equipment installation.
C. PROCESS DESCRIPTION
The smelter flow sheet diagram is shown in Figure 5, The
plant feed in the form of ore and concentrate goes to the Herreshoff
multi-hearth roasters. Byproducts containing arsenic are fed to the
Godfrey roasters. Analysis of the heavy metal and sulfur content of
a typical roaster charge during a recent test period is shown in the
following :
Cu As Sb Hi S Cd Hg' Se
1/20/75 1.0 22.9 3.3 0.3 0.11 29.6 0.02 0.0051 0.024
1/21/75 1.0 23.7 3.8 0.4 0.04 30.0 0.02 0.0041 0,018
1/23/75 1.1 21.9 2.8 0.3 0.04 28.8 0.02 0.0038 0.015
The arsenical material after Godfrey roasting will pass as
calcines to the fine ore bins for mixing and then to the Herreshoff
multi-hearth roasters. The hot calcines from the multi-hearth are
taken by larry car to one of two reverberatory furnaces where they
are converted to matte containing 35-45% copper. The matte is then
poured into ladles and taken by crane in the molten state to charge
the converters. Slag from the furnace is sent to the dump.
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As Ship
! Ore and Concen-
trate Crushing
] and Handling
! w/5 cyelortPR
82,000 SCFM
40,000 - 100,000 SCFM
2500°F
Sludje Hickel
EecyciLe
Plant Acid) Plant '51ag
0 to 100,000
SCFM
fl 500°F
Vent to Freclpltators
During Convert Rollout
Ship
Dore
Ship
I
*
Sodium
Selenite
Ship
.Residue to Roasters
or Ore Storage Bins
PROCESS FLOW SHEET
ASARCO /Tacuma Branch
prepared July ,1975
PACIFIC ENVIRONMENTAL SERVICES
Figure 5
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The converters produce a blister copper which is approximately
98-99% pure. This material is transferred by ladle in the molten
state to the anode furnace where some minor impurities are removed
by fire refining and the molten material cast into anodes, The
anodes are then taken to the electrolytic refinery where they are
reduced to electrolytic copper as cathodes or product copper. The
electrolyte from the refinery is passed to the nickel plant which
produces NiSO. for shipment, sludge which is recycled, and black
acid which is sent to the dore* plant. Refinery slimes are sent
to the dore' plant which produces dore1 for shipment and niter slag
that is sent to the selenium plant. Sodium selenide produced in the
selenium plant is shipped and the plant residue is recycled.
The arsenic circuit consists of the arsenic charge bin which
charges feed material to the Godfrey roasters for gasification of
the arsenic material. The gasified arsenic material is then passed
through the arsenic settling kitchens where the arsenic trioxide
is condensed in the various sections. There are three arsenic
kitchens, one ten chamber and two fifteen chamber baffled enclosures.
The nickel plant produces nickel sludge which is returned to
the smelter and nickel sulfate which is shipped for further pro-
cessing to other plants. Black acid is also produced and sent to the
dore' plant. The dore1 is shipped for further processing. Slag
produced from the dore' plant is sent to the selenium plant which
produces sodium selenite for shipment and residue which is passed
back to the roasters or ore storage bins.
Gases from the multi-hearth roasters pass to an electrostatic
precipitator and out the stack. Dust from this precipitator is
recycled. Gases from the reverberatory furnaces are sent to an
electrostatic precipitator and out the stack. Gases from the con-
verters are sent either to a 200 TPD liquid SO^ plant which produces
liquid S0_ or to a 200 TPD sulfuric acid plant. Gases from the con-
verter are passed to a multicyclone before going to individual gas
cleaning circuits for the liquid SO,, or the sulfuric acid plants.
-------
Offgases from the acid plant and the liquid SCL plant go directly
to the stack. Converter gases can also be bypassed directly to the
precipitator and then out the stack.
The gas cleaning circuit for each plant (the liquid S07 and
sulfuric acid plants) consists of spray chambers, precipitators, scrubbers
and mist precipitators to prepare the gases for either acid or liquid
SO- production. Gases from the roasters or arsenic settling kitchens
£•
pass to precipitators and then out the stack. Gases from the re-
verberatory furnace pass through waste-heat boilers and then through
precipitators and out the stack. Some of the gases from the conver-
ters during rollout are collected in the converter hoods and passed
by a separate fan-blown system through the precipitators and then
to the stack, Offgases from the acid plant and liquid SO plant are
passed directly to the stack,
Dust from the precipitators upstream of the liquid SO- and
acid plants may contain lead which is shipped to a lead smelter for
further processing.
Because of the nature of the ore received by this smelter
from sources such as the Philippines, Arizona or other parts of the
world, a wide range of products can be manufactured.
Nickel sulfate, dore', sodium selenite, copper cathodes,
copper shapes sulfuric acid, arsenic trioxide, arsenic, lead dust,
and liquid SO- can be produced.
Temperatures, volume flows and S0? percentage are shown on the
flow sheet, Figure 5.
D. EMITTING EQUIPMENT
a. Multi-_He_arth Roasters
There are ten Herreshoff multi-hearth roasters arranged in a
double row as shown in Figure 4. Roaster hearth area is 1345 square
feet with dimensions of 19 feet diameter by 25 feet high. The top
-10-
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of the roasters is approximately 40 feet from ground level,
There are usually five roasters used at one time. However,
there may be as many as six and as few as none in operation at any
particular time. Dampers are located in the roaster uptake duct
to isolate units not in operation. Roaster ore is heated to
approximately 900 F.
As is normally encountered with multi-hearth roaster,
considerable leakage is present throughout the associated duct-
work as well as the units themselves. This results in dilution
air entering the system and reducing the concentration of pollutants
such as SO,,.
The capacity of each roaster is 1200 tons per day. Eight
loads per hour is considered the normal production rate. One
load weighs approximately 6.5 tons.
b. Reverberatory Furnaces
Two reverberatory furnaces of approximately 1200 TPD capacity
each are installed. No. 1 has dimensions of 30' wide by 110' long
and No. 2 has dimensions of 32* wide by 110' long. The draft for
each furnace is generated by a steam turbine driven fan. Four Wag-
staff guns are used to feed each furnace at the side.
Most of the time, only the No. 2 reverberatory furnace is used.
Within the last two years No. 1 has only been used for a total time
of two months.
A negative .02 inches of water pressure is maintained auto-
matically in the reverberatory furnace during normal operation.
During charging of the furnace the control damper is opened wide by
manual overide to minimize pressure surges. The fuel supply is also
cut off for a present time of approximately 30 to 40 seconds to
minimize the occurrence of positive pressure.
-------
Maximum fuel consumption for the reverberatory furnace is
180,000 CFH of 1030 BTU per cubic foot gas. An air to fuel ratio
of 10 to 11 is used for furnace firing. There are three waste-
heat boilers downstream of the two reverberatory furnaces, one on
#1 and two on #2. Each of the #2 furnace boilers has a rating of
1000 horsepower and the $1 has a rating of 1890 horsepower. Gas
temperature is reduced from 2500 F to 700 F - 800 F across the
waste-heat boilers. Approximately 35 GPM of water is used in each
boiler.
c. Converters
Three Peirce-Smith converters have dimensions of 13 feet
diameter by 30 feet long and one Peirce-Smith converter 11 feet
diameter by 26 feet long. Normally only three converters are used
at any one time. Blowing is limited to no more than two at any
one time and generally a finish blow on one only will be conducted.
Normal converter cycle takes 12 hours. Total converter opera-
tion seldom exceeds 40 hours per day and has a range of 25-40
hours per day. The blowing rate will vary from 17,000 SCFM to
25,000 SCFM. With dilution air the volume flow from each converter
through the hood during the blowing periods is approximately 38,000
- 40,000 SCFM.
Sulfur dioxide of up to 10 percent has been measured immediately
downstream of the converter opening at the hood. Average SO per-
centages are in the 3-4 percent range,
d. Arsenic Circuit:
The arsenic kitchens are rectangular shaped, brick or concrete
ovenlike structures divided into 10 or 15 chambers. The gases are
continuously passed at very low velocity through each chamber
resulting in gradual cooling by radiation. The arsenic condenses
at approximately 400 F and is collected in the intermediate chamb«
in the kitchens. The condensed arsenic trioxide is removed
-12-
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periodically from the settling kitchens and placed in storage.
This material is either shipped as is or reduced to metal in the
arsenic trioxide reduction plant.
e. OtherEmitting Equipment
Material handling in the feed preparation area during crushing
or preparation operations generates particulates.
The anode furnace generates small quantities of S09 and
particulates.
Leaks in ducts and at other pieces of equipment can generate
SO- and particulates.
Ladles holding matte and slag will produce visible fugitive
emissions. The liquid SO plant and the acid plant will produce
small quantities of S0? in the offgas.
Dust from the precipitator handling the reverberatory furnace
and roaster gases is the major source of arsenic processed in the
arsenic kitchens. The converter dust obtained from the precipitator
handling the converter gases is also processed but since it has
a lower percentage of arsenic this material is recycled through the
arsenic roasters and then shipped to another plant for lead recovery.
The converter dust is processed at separate times through the
arsenic circuit. The arsenic in the charge is eliminated 20% from
the roasters, 60% from the reverberatory furnace, 10% out of the
matte and 10% out of the reverberatory slag.
E. EXISTING CONTROL EQUIPMENT
The coarse ores and concentrate handling and crushing area
has five cyclones for particulate collection.
Three electrostatic precipitators are used for brick flues
No. 1 and No. 2 to collect particulate before the gases from all
collection points in the smelter pass out the single main stack.
Since the two main brick flues join together and automatically
balance the flow, there is no complete separation between roaster and
-13-
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reverberatory furnace offgases. However, the two precipitators
in brick flue No. 1 (Fig. 4) generally treat the roaster offgases
and the single precipitator in brick flue No. 2 treats the reverbera-
tory furnace offgases. There is no S0_ collection for the roaster
or reverberatory furnace offgases. Water and sulfuric acid are
sprayed into the flues upstream of the precipitators for conditioning
and cooling. The gases that join at the roaster chamber and rever-
beratory flue are conditioned for precipitation by adding small
quantities of SO,, taken from the acid plant,
The precipitator in brick flue No. 2 consists of five sections
with six units in each section. The overall dimensions are 7T9" x
14' 0" x 72'0". The upstream pipe precipitator in brick flue No. 1
has two sections of 4-1/2 units each consisting of 84 - 12" x 15' x 0"
pipes per unit. The downstream precipitator in brick flue No. 1
is a plate-type of five sections, each section having four units each
8'6" wide x 7'6" long x 12'0" high. The precipitators are designed
to handle a total volume flow of 345,000 ACFM.
The single contact acid plant was originally designed in 1950
for 100 TPD at 3% SO . It has been enlarged to the 200 TPD capacity
at 5% SO and is capable of handling 23,000 SCFM.
Acid production record in tons:
Year Tons H SO,
1969 38,379
1970 37,485
1971 40,154
1972 22,230
(first half)
The acid plant precipitator is designed to handle a volume
flow of 34,000 ACFM.
-14-
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The liquid S0? plant processes up to 45,000 SCFM of the con-
verter gases. This system uses dimethylaniline (DMA) for absorbing
the gaseous S0_ and then regenerating by stripping with steam. The
concentrated SO^ is produced as a 100% gas. It is liquified by
compression and is then stored under pressure. A description of the
DMA process is included in Appendix A,
The DMA concentration plant contains 20,000 gallons of DMA
which is passed between the pregnant tank and the stripped tank.
When there is no SO- being generated by the converters, the system
operation can be cut back so that very little DMA is processed.
Some of the liquid SO is shipped to the east coast under a
contractual agreement that ASARCO has with a chemical firm. This
long shipping distance results in a net cost to ASARCO for S0_ pro-
duction. The price of SO. must be competitive with that produced
from elemental sulfur burning,
F, GAS SYSTEM pUCTWORK
A plan view of the interconnecting ductwork between the
roasters, reverberatory furnaces, converters, acid plant, liquid
SO plant and the stack is shown in Figure 4. Gases from any one
of ten multi—hearth roasters pass into the roaster building flue,
then to the roaster chamber or settling flue and then to the junction
with the reverberatory furnace flue. Gases from the reverberatory
furnaces pass through waste—heat boilers, then to the reverberatory
furnace flue. The No. 1 brick flue takes most of the gases from the
roaster building and No, 2 brick flue takes most of the gases from
the reverberatory furnaces. However a crossover link is installed
to allow system pressure balance. The draft is obtained from the
563 foot high main stack and is 2" W.C. at the base. Duct dimensions
are shown in Figure 4. Gases from the converter hoods are drawn by
two hot gas fans and allowed to pass either to the liquid S0~ plant,
the sulfuric acid plant or to the stack. An additional line is used
to provide SO,, from the acid plant to condition the gases for the
final precipitator treatment.
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A separate vent system connected to the converter hoods, is
used during converter rollout to minimize fugitive emissions during
the non-blowing phase. Not all gases enter the hood during this
phase because of geometrical considerations. The duct is connected
to the brick flues which pass this gas out the tall stack.
Elevations of principal ductwork are as follows: (All eleva-
tions are to the bottom of the flue).
No, 1 Brick Flue 67« - 150'
No. 2 Brick Flue 67f - 150'
Roaster Chamber Flue 54'
Roaster Building Balloon 65'
Flue
Reverberatory 50'
The acid plant and SO™ plant offgases are vented to the main
stack downstream of the precipitators.
G. SULFUR BALANCE AM) GAS COMPOSITION AT SYSTEM EXIT
Typical _Sulfur Balance Data - TPD Sulfur
From ore concentrates charged 270
To 100% sulfuric acid produced 39
To liquid SO produced 71
To slag 6
To other waste (not emissions) 2
To SO, emissions 152
The above are recent typical data based on monthly measure-
ments. Reference 2. Table 1 summarizes representative sulfur
balance by emitting equipment.
S09 concentration at the outlet of the multi-hearth roasters
was measured to be 1.5% with 3.5% to 5,0% water. SG_ concentration
at the outlet of the precipitators in brick flue No. 1 was 0,6%,
Reference 3.
-16-
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TABLE 1
ASARCO/TACOMA
AVERAGE SULFUR BALANCE SUMMARY
Sulfur
Input
TPD-S
300
Roasters
(Uncontrolled)
%so2
1.5
TPD-S
60
Reverberatory
Furnaces
(Uncontrolled)
%so2
1,0
TPD-S
84
Converters
(Partially Controlled)
%so2
3 to 4
{up to
10%)
TPD-S
141,6
Slag and
Solid Waste
(Controlled)
TPD-S
4.8
Fugitive
Emissions
(Uncontrolled)
TPD-S
9.6
(By difference)
Sulfur j
Captured
(Slag and Acid Plant)
TPD-S
158.4
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Suspended particulate in tons per year, and SO in tons per
x
year for the years 1971-1975 are shown on Table 2, Reference 4.
Low level sources near the plant that have had some control
are listed in the following Table 3 (Reference 6), Dates show
the date of control.
Figure 6 and Figure 7 show mass distribution of particles
upstream and downstream of the precipitator in brick flue No. 1
which carries most of the gases from the roasters. As can be seen,
the precipitator takes out a major portion of the . Ijj. to 10u.
material but does not effect the less than . Ijj particles to as
great an extent. Mass mean diameter at the precipitator outlet
has been determined to be . 12 u. , std. dev. ,162 jj. (Reference 6).
Particulate emissions from the tall stack (from all plant
equipment) are estimated by PSAPCA and ASARCO as follows:
Material T/Y AS2°3 T/Y
Total Part. T/Y AS20 T/Y Under 3.2u Under 3.2
(Reference 6) (Reference 6)
ESP ASARCO
(Estimate) 150 80 99 52 (3)
PSAPCA 191 102 140 72 (3)
(Estimate)
The chart, Figure 8, shows the sulfur captured by month during
1974 and 1975 from the converter gases related to sulfur input in
the matte. This shows the relative sulfur captured in the slag,
liquid S0_ and sulfuric acid and indicates the major improvement
obtained with the liquid S0_ plant.
H. GAS CHARACTERISTIC VARIATION
The SO- concentrations in the offgas from the reverberatory
furnace will vary significantly depending upon the charge rate and
the various sulfide materials contained in the charge. The normal
-18-
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Table 2
TACOF1A SMELTER EMISSIONS ESTIMATES
PARTI CULATE TONS/YR
YR,
1971
1972
1973
1974
*1975
TALL STACK
ARSENIC
TRIOXIDE'
506
228
176
164
80
CADMIUM
3,4
1,6
1,2
0,6
0,2
TOTAL
970
438
335
308
150
LOW LEVEL
As2o3
296+
281+
• 266+
167+
90,+
CADMIUM
2,0+
1,9+
1,8+
1,5+
,98+
TOTAL
1285+
1218+
1145+
967+
682+
SOX TONS/YR
m
164,600
156,000
148,000
117,900
99,600
d&
6814
6460
6127
3414
3400
i-O
1
+ INDICATES THAT THERE ARE LOW LEVEL EMISSIONS WHICH.HAVE NOT BEEN MEASURED OR ESTIMATED,
* 1975 ESTIMATE BASED ON ASARCO REPORTS FOR JANUARY AND FEBRUARY,
Reference 6
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TABLE 3. LOW LEVEL EMISSION SOURCES Date of
AND CONTROL TECHNIQUES Control
1.
2.
3,
4.
5.
6,
7.
8.
9.
10.
11.
12.
13.
14.
15.
16.
17.
18.
19.
20.
21.
22.
23.
24.
25.
26.
27.
28.
29.
30.
Wind Blow Dust from ASARCO Property
In-Plant Road Dust
Improve Matte Ladle Loading Hood
Arsenic Storage and Loadout
Dust from Converter Flue Unloading
Conveyor for Arsenic Feed Plant
Larry Car Covers
Reverb. Furnace Slag Launder
Reverb, Furnace Charge Guns
Flue Dust Handling
Converter Fugitive Emissions
Ore Roasters Fugitive Emissions
Slag Bumping
Gravel Roads Outside Plant
Wind Blown Dust Outside Plant
Sealing Arsenic Building
Anode Furnaces
Reverb. Furnace Slag Launder for Converter
Minimum Blow on Converters
TallStack
Metallic Arsenic Plant
Original Cottrells (ESP)
Acid Plant
New ESP Rappers
New ESP Voltage Regulators
Use of SOo for ESP Dust Conditioning
Liquid SO? Plant
Roaster SO? Control
Bagtiouse for Arsenic Plant Flue
Ventillation As Pulling for Kitchens
6/73
6/73
2/74
2/74
3/74
4/74
11/74
5/75
2/75
5/75
7/75
7/75
4/76
12/75
1917
1950
12/71
12/73
7/74
7/74
-20-
-------
Mass distribution of particles
upstream of the #1-electrostatic
precipitator (assuming particle
specific gravity = 5.865).
Legends
0 test 3, Nelson impactor
fest *f» Nelson, impaetor
Test *f, UW Mark II irapactor
Test 6, Nelson impactor
^
10
-------
Mass distribution of particles
downstream of the #1 electrostatic
precipitator (assuming particle
specific gravity = 3.865)
'Figure 7
Legend;
O Test 1, Nelson impactor
Test 2, Nelson iaspactor B.S P
D Test 2, UW Mark II impactor
Test 5i Nelson impactor (baghous^
Q Test ?t Nelson impactor (baghoueef—
L~LjJ4 •
,.| 'I TV..-.. --:.-. :•:..;•:. 1-.. I
,0001
-22-
10
-------
Figure 8
ASARCO - TACOMA
CONVERTER OPERATION SULFUR BALANCE
Tons Sulfur In:
leyerb. Matte chgd,
to Converters
Liquid S0~
Converter Slag
FMAMJJA SO'NDJFMAMJJASOND
-23-
-------
or average charge rate into the furnace is four loads per hour.
However, this can vary between two and eight loads per hour. This
"variation is a result of intermittent pollution control and smelter
operations and can be controlled only to a limited extent. Table
4 shows the effect of variation in charge or dropping rate into the
furnace on the percent S0? concentration in the offgas. These
measurements (Reference 5} were taken primarily in the steel flue
immediately downstream of the No. 2 reverberatory furnace. The
firing rate will also have an affect on the percent S0?. Table 5
shows a variation from .16% SCL up to 1.52% S0«. This occurred over
a volume flow range of 33,338 SCFM to 54,600 SCFM.
Table 5 further shows the potential variation in SO concen-
tration. For the date of 2/16/70 the average percent SO,, between
drops was 1.0%. This occurred at a charging rate of 6 loads per
hour. Maximum peak percent S0_ during this same period was measured
as 13.0% but there is considerable question as to the accuracy of
this number. The average of peak values for this same period (1
hour) was 6.5%. Thus, it can be seen that between at least 1.0%
and 6.5% can be encountered over a relatively short period of time.
The second set of data in Table 5 had a charging rate of 8 loads per
hour and indicates less of a variation but still shows a peak of
5.0% to an average between drops at .75%,
From these data it can be said that peak S0_ may vary between
7-13 times the average percent S0_. Any control system must be
designed with this variability in mind.
SO,, concentration in the converter offgas also varies con-
siderably because of the batch nature of the operation. Also, the
variation in actual metallurgical operation between slag blows and
copper blows will cause a variation in percent SO-. Between blows
the converter may be rolled out for slag pouring or material
charging. When the converter is not blowing the hood above the
converter collects the gases and passes them to a separate vent
system. See Figure 4.
-24-
-------
Table 4.
45-Minute Sampling (3 Drops)
Date
/21/70
121
127
713
/16
ii
tt
ii
!!
rt
ii
(i
ii
n
ii
712
713
713
Dropping Rate
Loads/Hour
8
7
7
5
2
6
6
4
5
5
4
4
4
4
6
5
6
6
% S02
Shell Keich
-
1.09
1.55
0.82
1.07
0,16
0.26
0.49
0.15
0.21
0.21
0.45
0.21
0.28
0.30
0.43
0.45
0.32
1.64
1.21
1,52
1.40
Volume
Std. cfm
_
-
-
-
37,586
39,439
33,338
-
-
-
-
-
49,700
54,600
52,000
48,700
Tons S
Elim./Hr.
_
-
-
-
_
0.22
0.23
0.41
-
-
-
-
-
2.23
1.81
2.21
1.87
Sample Location
#2 Reverb. Uptake (Dpstrm. W.H.B.)
#2 Reverb. Steel Flue (Dwnstrm. W.H.B.)
ir
II
II
it
II
n
II
II
II
II
II
II
II
II
II
"
-------
Table 5.
Reverberatory Furnace Sulfur Elimination
As A Function of Charge Rate
Date
2/16/70
It
11
9/10/71
rt
it
Dropping Rate
Loads /Hour
6
6
6
8
8
8
%
so2
1.0
13. GO)
6,5
0.75
5.0
4.0
Volume
Std.- cfm
51,300
51,300
51,300
51,000
51,000
51,000
Ton S
Elim. /Hr
1.41
18.30
9.14
1.04
6.98
5.59
*
Sampling Period
Average between drops
Max. Peak during drop
Average Peak during drop
Average between drops
Max. Peak during drop
Average Peak during drop
Sampling was done in #2 Reverb. Steel Flue
-------
The attempt is always made to maintain at least one converter
blowing gases into the system at any given time. Usually a converter
will be provided with 18,000 - 20,000 SCFM to the tuyeres. An
additional 100-120% of dilution air is generally estimated to be
added to this gas flow resultiag in a total gas flow from each
converter in the range of 35,000 — 40,000 SCFM. When a converter
is blowing there will usually be approximately 38,000 SCFM and an
SO- content in the range of 4,0 to 4,5%,
Because of the above, the gas volume flow from the converter
line to the control system acid plant and liquid S0« plant can
vary over a wide range from maximum to zero. Stored liquid S09
can be fed to the acid plant when the smelter is not generating
a sufficient quantity, thereby allowing the acid plant to operate
on a continuous basis to minimize startup inefficiencies and
corrosion. Because of contractual commitments, ASARCO is generally
not able to operate in this manner.
I. STACK DESCRIPTION
The 563-foot high stack has a top diameter of 24 feet. The
top of the stack is located 713 feet above sea level.
Inlet temperature at the bottom of the stack is 185 F.
Stack construction is brick and mortar with an acid brick
lining.
The acid plant and liquid SO,, plant offgases are ducted to the
main stack.
There is a preheater used to heat the gases going up the
stack. When the preheater is not used a temperature of 150 F will
be reached 200 feet up the stack. When the preheater is used, a
temperature of 250 F is reached at the 200-foot elevation.
— 27—
-------
J, PRESENT TECHNIQUE FOR SOLID-WASTE HANDLING
Slag is sold for sandblasting, roof granules or portland cement
aggregate. Dust taken from the dust collection devices are recycled.
Lead containing dusts are shipped to the Helena, Montana smelter for
processing. Dusts high in arsenic are processed through the arsenic
circuit.
K, FOOTING AND STRUCTURAL REQUIREMENTS
Most of the smelter is constructed on fill slag and some saw-
mill wastes are the primary fill constituents. Pilings, installed
by drilling and driving, are required on 3-foot centers. City of
Tacoraa local codes apply. Seismic zone 3, wind load 25 PSF, and
snow load 15 PSF are used for design.
L. EXISTING AND POTENTIALLY AVAILABLE UTILITIES
There is an abundant water supply and it is expected that any
new control equipment can be supplied with the existing system.
Future increases in gas usage as fuel are unacceptable due to
the decreasing availability of natural gas. There are no additional
loads that can be supplied to the gas system. Direct-fired and
waste-heat boilers provide steam for compressed air, heating and
S0_ DMA stripping. The #1 furnace waste-heat boiler is rated at
1890 HP and 65,205 Ib/hr of steam and the two #2 furnace waste-heat
boilers are each rated at 1000 HP and 34.500 Ib/hr of steam. Tacoma
City Light Company provides electricity required. The available sub-
station is now operating at approximately 75% capacity. There is an
additional 5,000 KVA capacity available.
M. POTENTIAL NEW CONTROL EQUIPMENTINSTALLATION PROBLEMS
One of the major problems at this particular smelter would be
to find space for additional control equipment near the emission
source. The Tacoma Tide Lands area would appear to be the most
logical for installation of any extensive control equipment. As can
-28-
-------
be seen from Figure 3 the plant area is fairly well crowded with
buildings, flues and equipment. The area adjacent to the street
is also a potential space for control equipment, though it also
is some distance from the major emission sources. The area along
brick flue No, 1 adjacent to the metallic arsenic area is also a
potential space for control equipment. The smelter is obtaining
to obtain a. permit to fill ten acres with slag up to the 1961
inner harbor line which could be used but at additional fill
expense. The 50' x 100' nickel plant will be torn down in the
near future making this site available for new equipment.
Tests with a pilot baghouse were performed to compare bag-
house collection efficiency with electrostatic precipitator
collection efficiency. The tests indicated that the baghouse was
approximately 25 times better at collecting particles less than 1
micron.
-29-
-------
REFERENCES
1. Discussion with Mr. C.H. Randt, Assistant Manager ASARCQ Tacoma
Plant.
2. ASARCO sulfur balance, March 1975,
3. Puget Sound Air Pollution Control Agency data taken using
Ritagawa tubes and Umgard pump.
4. ASARCO Data, 4-14-75.
5. ASARCO data.
6. Puget Sound Air Pollution Control Agency data and calculations.
-30-
-------
19SO
INDUSTRIAL AND ENGINEERING CHEMISTRY
22S3
•jture combustion. In this case, a preheat of over 500* C, In
.. p$ would be necessary to maintain the required temperature
. ;]g reduction furnace.
.toco was considering the installation of a commercial 35-tori-
.nhy sulfur unit at Garfidd in 1944. By that time, however,
.. leasehold requirements of Salt Lake City for natural gas dur-
I ide winter months became so heavy that existing pipe lines
«IJ not supply this demand and at the same time carry the
iiistris) load. Tlie project wns therefore shelved.
LITERATURE CITED
(1) Fleming, E. P., and Fitt, T. C. (to American Smelting and Re-
fining Co.), U. S. Patent 2,270,427 (Jan. SO, 1942).
(2) Ibid,. 2,388,259 (Nov. «. 1945),
(3) Ibid,, 2,431,230 (Nov. 18, 1947).
(4) Pulton, Chan, H., U. 8. Dept. Interior, Bull. 84 (1915).
(5) Leeds & Northrup Co., Philadelphia, Pa., private communi-
cations.
(6) Lepaoo, E., IKD. EKO. CHEM., 30, 02 (1938); 32, 810 (1040).
(7) Young, S. W., Trans. Am. Intt. Chem. Engrt., 8, 81 (1915),
RICEIVEB March 27, 1950.
LIQUID SULFUR DIOXIDE FROM
WASTE SMELTER GASES
Use of Dimethylaniline as Absorbant
EDWARD P. FLEMING AND T, CLEON FITT
American Smelting and Refining Company, San Francisco, Calif.
MI1E American Smelting
I and Refining Company
4 for the past 30 years,
"rn engaged in investignt-
i various methods for re-
wring sulfur dioxide from
'•i waste smelter gusos
•A< tho twofold objective
• muiinizing sniolce com-
iteand perfecting aproe-
••*'hat could compete with
"sustnne in the sulfitc
..ij»r pulp industry. Over
'-i period, pilot planta of
)m 1 to 15 tons' capacity
:-i'« been operated, using
'•M Haenisch-Schrooder
'•ilcr-absorption process
'), direct compression of
''''•grade converter gaa in u
'•••"tt-pcwlay pilot plant (fl),
:!* ammonium sullitfi-binul-
*'-ii cycle (4), the Lurgi
>«lplii<]uic" praeeas uwing
V'lklmo in water suspension (0), and finally tho Asarco process
••"lEiiiiiictliyliuiilino (I, S), Laboratory experimontnl work wiii
"> I'liwluctud on other reagents, particularly Imperial Chemi-
-'ibiwic aluminum sulfatc (/, 7) and I,urgi's toluiler to orMtrato and also
''J<:>! KIP proccivi cynln of operation, patented by American
•••iiiH! !>'id Er-finiriR Oompany, i«:rmitted material savings in
•i.'Xit- lo:^-i, Htenni cmifluinptioti, and labor cost as compared
•'••' U'i: I,urj{i cycle as operated in 1'luropo by MetuHgescllHchaft.
"* s'llphidiixs Kystem a-s developed by MetullKesellBcliaft
•' f< >[ of .separate unite for alworplion of nulfur dioxide, recov-
.' "f xylidiijc, vujwr in tiwd Kwubber Holutwm, ri'.gnueration of
.'; inn sulfate with H«lu ;«,h and vouling to 2° O,, unit (k-.wption
• iliiir- di(K\'wlu. These various oporjitionn involved considftr-
•'"••' n-i'pf.nl losa, excessive labor, and high steam coiiNumntion.
paper reviews tha various pilot plant investigations
conducted by tha American Smelting and Refining Com-
pany during the past 30 year* with tha object of perfecting
a process that could produce liquid sulfur dioxide commer-
cially from waste smelter gases* Processes developed along
these lines in Europe are briefly discussed and reasons given
£01* the selection by American Smelting and Refining of
anhydrous dimethylaniline as its preferred reagent.
The novel features of process system and plant construc-
tion are described in detail fay reference to the flow diagram
of the 20-ton plant installed September 1947, in the com-
pany's load smelter at Selby, Calif. The benefits of the im-
proved system of operation, as compared with the proce-
dure followed in European plants, are emphasized; among
these are high purity of product and facility of operation.
Basic data aa indicated by 1949 operations at Selby are
given, covering such items as reagents, steam, power, cool-
ing water, labor, and supervision. The possibilities of the
process' being applied to the recovery of sulfur dioxide from
low-grade industrial gases by the use other reagents having
m high absorptive capacity for the gaa are briefly noted.
The priucipul uovi-I fea-
tures of tho Asjirco process
using dimethylanilino rea
ge,nt consist »f :
1, Incorporating the re-
generation unit for treat-
ment of recaptured di-
lucthylunilme sulfnte as an
inteRrnI part of the a-lworp-
tion-ilfKoqjtii'ii cyolt; !hi.s
sjivrs labor ;ind steam :ui-
tion-dcsurptinii cyeic :mrriiiiioti.
3, iimlallinj; just above
the absorption .sitflimi «f
tower, two inibbk1-e:t[> tr;ivs
where (he sodium carbonate
_ solution is eonvi'i'letl to so-
dium sit Hit R <>r bi-itilfile bv
tho rwidn.'il sulfur dioxide
In tlio exit gases; this pormits regcneniHon of diiuotbylaiiiline in
thn closed ubsorption-desorption eyele, a]k)wing (lie eont'euirdti'd
siilfiif dloxidi) to (siitur tha wmipwssof fi'oo uf enrhuti iliii<,iti.'.
4. llecapturing prautieally all the diinelhylaiiiliiH' v.ipor,
which has oseupwl from tho absorption tower, in a bubble-cap,
nine-trny exteiiHioa of the HIIIDO tower wliere tho vapor i,< si-nil'beit
with dilute Hulfuric acul flowing counlerKurrenl to u:i>- How.
5. Hecovering and returning u eimsidorable port km of tin*
diiURthylaiiilino to tho tilMorlxtr without the neeawi) y »if !i,-:iling
it in tho main regi'iierat iun unit,
A comparison of dimotliylaiiilino and .xylidino, as u
sulfur dioxide, B!IOWS that oitoh has some iulv:u>hi
other, Dinietliylanilino is lined substantially dry
dinoin used in a mixture of one-half xylidiiu! and oiif^-
TSio ability of dimethylunillne mid xylidini* tn ab.-.o,
oxiJo from fluo gun is Khiiwn on Figure 1, eurvi',-t ,1 a
ttbsorptiim isotherms show that xylidine, curve H, n »
Borbant for sulfur dioxide in tho lower pwenttiyi'S by v
dimethylanilino, curve A, u a bettor nbsorhanl for
-------
2254
INDUSTRIAL AND ENGINEERING CHEMISTRY
Vol.
in tin- hvlior concentrations. The two isotherms cross nt about
U..V", fiutfur dioxide by volume.
Tl\e Mobility «( s«lf«r dioxide from g»s mixtures in ditneUiyl-
flnilii',0 follows Henry's linv, but this law docs not apply when xy-
lidine ix u»'d. ID this case lew hen!, would be generated in the ab-
sorber when treating the higher grades of sulfur dioxido with di-
njctlivtaniline than with xylidine. Thin would entail ft less ef-
ficient cooling system when using dtmpthylaniline.
100 (SO 200 2SO SOU 55O
fUR BOXIDE CRAMS PER LITER AT ZO-Z3* C.
00
1. Absorption IsotHerrtiB of Sul£ur Dioxide
tuUur cUomide and xylidiri* (1:1 *ylicHn»
[*miHn«; Curir»
imdi w*t«r)
The vapor pressure of dimethylaniline at 20° C, 18 0.35 nun.,
and tln> vapor presMire of xylidinc nt the same temperature is 0.20
mm. This indicates ;i slight saving of sulfuric acid when re-
covering xyhumc v;ij>or a.s compared with dimethybmilino vapor.
The. Fohibi'iiiy cf dimethylaniline sulfato in water is much
(CrenU'r t'i.'in the solubility of xylidino sulfate in water. There-
fore, the weak sulfiirie aoid solution from the scrubbers, when us-
ir,ii dir.iethyl.inilitie, can carry a much greater lo.id of dimethyl-
.tnilino to (he regenerator than when xylidinc is used. To some
extent this jjrcatcr sohtliilily would offset the Advantage of the
lower vapor pressure of xylidiiie.
During the absorption of sulfur ilioxklc with cither dimethyl-
aniline or xylidiiic there is scviue oxidation of sulfur dioxide to sul-
fur trioxUU: iifthoiiKh in the trcntment of gns containing 3.5%
sulfur dinxido or over, the conversion is cjuitc small, being !ij>-
proxtiuiitoly O.HO^J,. in She. treattnfnt of gas under this grade,
the j>ereent!tn<« of <>\id:ition imircjLies rapitily, pnrticulnrly with
thr u*(' of xylidine in iv.-iter ."-'uspension.
In the diniRthyl.'uiilinc prowss all t,h«> water nliniinnted as steiim
from the recenrrntiiifj ;ind stripping operation in condRris«i. Af-
t anhydrous dimnthylrinilino in the gravity
wpiir.-itor, all UK- wa(<-r pli.'im> is returned to the regenerator.
I'nder these eojiditi'iiis the su'fafe radical which forms is continu-
ously removed from the iilisorptiou cireuit thus eliminating the
pos>ih]e formation r>f any Kc^litl reaetioEi products.
With the use of the xylidiue-water wisponsion process, great
care mart bft taken to prevent the formation of solid reaction
products, even when treating K!'S relatively high in sulfur dioxide.
In this case, if tiie sulfatc radical in the water phnse is not kept
within low limits by bleeding sufficient water to the regenerator,
rapid mitoxidalion triA«-s plare to the extent that the xylidine sul-
fate, having a low watilitit> ],v
tin; advantage, of lower uteum consumption, and the prom^ r,,
quit'eH fewer skilled operator and I«'NH wipervisiou. Also tlr
very low grart,
would bo Jitt.le difference when using the Awirwi wywtflin of OIKTI-
tion. In the opinion of the ntithors the advantages of diiiK'tiiv).
aniline nrc such that it enn be u.sed competitively with xylidine on
sulfur dioxide gsts w low HH 2.0% by volume.
Following 0 months' operation of a 1-t^iii diinethylanilmc nt
Horption unit on 0,0% milfur diox«!e gan at Oarfiold, Utah, it »a,
decided to build a 2.5-t
-------
Kovember 1950
INDUSTRIAL AND ENGINEERING CHEMISTRY
2255
time of the Norwegian installation, but Aauroo took no part hi the
fcign of plant, und tho operation there did not follow the pre»-
{ process system us installed at Selby. Iteccntly, changes have
ten\ made at Kristiansand to tako advantago of some features of
he Asarco process.
The present plant at the Sclby lead smelter went into opera-
ion in September 10-17, In order to take cure of the bulk of Fa-
ilic Const ree|iiirenicnts mid allow a surplus of 100% sulfur dio.x-
i1 i'.n» tor emii'Iiing HIM) pliibili/.ing the supply to adjoining
id (limit, thu design ciilleil lor u enp«ellj' u{ i!tl lonw pur ility,
his wiis biiM'd on a supply of gas fi'nm Ihvight-Lloyd sintoring
;icliin«'fi averaging 5,0% sulfur dioxide by volume, As regards
limit capacity, atciiui I'niiNuniption, dimutliylunilino loss, and
icilily of o|n-ration lln» unit IIHH (weeedi'd exiH'Rtiilions.
l>l«iiitiuiw iluritig IIIH> indicate the following biisiudutai
Iti'rovrry uf KOi from &.()','» Jinn, %
UinH'thylamlini! I'uBmnm-d/tim SOi prodm-pd, 1b.
SuMiium I'urhotm!*1 eniimimcil/toii SO? produced, Ih.
Snlfurk ai'i'l t'«!ri'nimf1*&/tou HI*; pro^m'c*!, Ib.
Su-am e<3n.«uiui:d./lim BOi i^rodtKvd, tim*
POVKT", kw.-hr.
Cooling wiitcr at (i5° FM giiJ./miii,
t)u,o
1.1
35.0
40 0
1,2
145
300
11 Provided OH' SOt in pro
R|>pr«ximHU'!y 100 kw.-lir.
SB n 100% ga^ puwer conauniption will be
These datu do not include labor, power, and water used for the
purification of gas prior to entering the sulfur dioxide plant proper,
The labor required to oiwratc the plant consists of one foreman
on day shift only, thrw wliift operators, uiul on« ipsnnrul utility
limn on tiny f.tiifl. Tlu> MLIIHI ITUW I'uii upcriLte a pltuit of mtvoral
timcM ScWiy'M capucity. In addition, Mii]M'rviNioii and HOtnu vlunuU
cal control wurk urcrniuiiwl.
It i« iliff'ieult ut tliis ti)ni: lo pivi' a fair I'Htiinutu of miiinteiiuiioo
rusts. Tlic* plant hu>) tii'cu going tlsrough a dewlopntciit stage in
tlip scl(H'tinn of tlit! best corrosion resistant jiiBturiul, Recently,
lead has bei-i» substituted for 3I('» Htiiinlcsa KUsel in the coiiBtruo-
1iru.te gus purification wystem at Selby is nec-
WiHiiry lii!cauw> of tho high impurities in the gits stream.
T
ine
can
rel
ASARCO SULFUR DIOXIDE PROCESS
ho proeusu fur the recovery of eulfur dioxido from flue gna by
is of dimi'thylanilinu ubsorbant, UH duvelopisd by the Ameri-
Hmeltirijj; and Itiifining Company, consists essoatially of two,
ted clo«t;d <:iriiiiit ojHirationB, curriwl out siinultiuioously, in
twfj main bubble-cap towers- nttmi'ly, tho absorbing towor
the htri)i[iiii|{ tower, Tho first operation eotiNwtB of recov-
of Kiilfur dioKidi; from lliu (ItlcgiiK by absorption in diimnhyl-
im: iind its wib«e(|iiuiit stri|j|)iii« I'nitii Uici j>rijMTuti«>ii itoimislH f)f tho recovery of the
iclliyliiiiilinc which CWUJM« into the gan sttrenm during tho ab-
itiiui (tjii'j-jiti«»ii and from Shut dksolvod in water dtiriiiK thn
pptiij; ijpcnition. Without tlio recovery of dimethyhutiliiiB
prMiilici' through metering
devices from the supply in the- ditiielliyhiniline Mir^e t;uik. The
sulfur dinxido dissolves in tin* dimelhylaniliiie, and as Ilie Hue H.'I.H
iMteunicH impuvt'fishril in sulfur diitUtle i( bi-eonie.-: enriched with
dhucthylsnUuio vapor. Tlie diriH'thylutuhiic in (Utuii^ tlown-
Wiinl from tray to tray becomes richer in ili-isnlvc.l sulfur dioxide
mid changes in color from light-yellow to a deep rul'v-rcd solution.
Considerable heat w evolwd during tin' :ibsi>iptioti of sulfur di-
oxido by the dimt'thyhinUini1, iiml inleivonlers :md putupx aro
-------
2256
INDUSTRIAL AND ENGINEERING CHIMISTBY
Vol. 42, No, 11
Figure 3. Flow Diagram of Aaarco Ijiquid Sulfur Dioxide Plant
provided on the .'ibnorber to dissipate this heat of solution. Tho
qunniity of sulfur dioxide which a given weight of ditnelhylaniline
tun
-------
November 1950
INDUSTRIAL AND ENGINEERING CHEMISTRY
2257
, • - • -
iiaij • -t JfCiittifiaiP -iiifft'*1"-'ij
Figuro 4. Irutitament Panel, Selby Liquid Sulfur
Plant
Tin1 !lu>- gns LS impoverished in sulfur dioxide and enriches! in
ilmicthylanilitie vapors while po-ssing through the ateorber unit,
Thf due g:w leaves the absorber and is bubbled through two trays
of dilute sodium carbonate solution in tho 8oda scrubber. Any
FKi'hiul auUur dioxide in Uio flue gtus converts the sodium carbon-
ate to siodium stiinte or bisulfite, Tho carbon dioxide is liber-
als! in (lie flue gas. Any spray or droplets of diniethylaiiilme are
irapix'il in this section and escape with the liquid effluent from
tins unit.
The fhir» gits substantially free of physical ditnethylaniline liq-
uid but containing vapor of dimethylanitine is caused to bubble
through nine trays of bubble cups irrigated with a dilute sulfuric
tirid solution. The acid and the dimcthylaiiiliwe- base react to
furiiidiiiu-lliylaiiiliiiCflulfute.
The dilute sulfuric acid is fed onto the top truy of the third unit
of ;!«> MisoyVmn UIVMT or tin* nr.id scrubber at a rate to almost
t-'atiiriife tht" ncid with diinethylamlme on tho bottom tray of this
ii.'iit .in.! to maintain n concentration of dimethylaoiline in the
ii i-1 sampled from tho top (ray of less than ono twentieth satura-
tion. 'J'lit flue gus which leaves tho tower at this point and flows
into Uu.' atmosphere contains a fraction of 1% of sulfur diosade
and j>r;;t'lien1iy no dimethylmiiline,
The eH'uent from the soda truyet and the acid scrubber empties
ia'o :i tdlWlJnc tank and is pumpL'd up to asma!! gi'avity separa-
tor, wlmri! ;i ;it, vnlv.; l,n :i
pll cell and then to tho newer, Tho sodium mil fate fomu-d in (lit;
regenerator iu thrown to wiujte.
The. pll of the water Molution in tin) regenerator i.s niainS.'iincd
betwiicn 5 and 0 and is adjusted by the rule of How of sodium car-
bonate solution to the soda .scrubber. The ellluent water con-
tains no dissolved dimctliySanilinc.
There are only three passible Kourrofi of low <>f dinu'thyluniline
from (he process cycle - namely:
1, A,H dimel.hylnnilini! vapor cHeupin^ from the absorption
tower with th« iiupovcri.shed flue KHH
2. AH dimcthylaniline dissolved in the water effluent from the
As mechanical leaks in pump glands, valve packing glands,
and pipe threads
The firet two sources of loss are recoverable and may !«; (fon-
trollod by correct operation of the process, and tho third source of
loas is preventable.
The operation of the Asarco process is smooth and flexible.
The plant may be shut down and started up without dilFieulty.
There arc only six control valves on the process; these control
solution flow rates, and the levels of liquid iu ihc various units are
automatically maintained by float valves. There is no juggling
of flow rates to maintain normal liquid levels in the units irt the,
two bubble-cup towers.
The operation of tho plant takes place principally from one
T'
f
Uiij,
I ••-* ,,
1
til
JDioxid*J?!«\.t
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2258
INDUSTRIAL AMD ENGINEERING CHEMISTRY
Vol. 42, No.
fUw and from one instrument pmifl. This is nhown in Figure -f,
Tl»> utstrumrnls consist of ft temperature recorder, » vncuum wwl
pro-ware Rftff for blower nnil n.1 unii^r, integrating and recording
line i;;i.s fltnnnrtrr nml steam flnwmotw, rolmnotor for liquid flow
control, and rnuole iiulirnlitiR (.,'tnk level RBKW, Tho IliHtrit-
iiionis !ils 130
New York, MrfirawJIiU Hook (Jo., 1riv(it,p invmtiKntion, American SmHtin;; nni|
IteliniiiK (^o., Tacnmii, Waeli. (HI29).
(7) Sulphur 1'ntent.n Jf Su|.
phtlr from Smelter (Simon" (1000),
(») Tlimnw, M. !>., Ivio, J. <)., »n,\ Kilt, T. f!., INO, KVK. fHn,
AMAT,, Kn., 18, .18,1 (Hun).
(!)) Woicimntin, If., and llrsraitior, d,, Mi-taHgr*, /VnWi'c /irf |j
7-13 (IflOT); Ind, Krtg. V.hrni., Ntw* Ed., 14, 1r»!j {llKJfl).'
RBOIHVIB March 27, tflfifl.
Recovery of Sulfur Compounds
from Atmospheric Contaminants
MORRIS KATZ
D*f*nc* ReiearehOh*mlcal Laboratories, Ottawa, Canada
R. J. COLE
Ontario Rafiaareh Faundallon, Toronto,
I ho ciniraion of sulfur compounds, rocognlzod &e major
atmospheric contnintnants, must be reduced na a matter
oi economics and in the interest of public welfare. Great
strides have been made in the control oi smelt«r smoko
damage by scientific investigation of sulfur dioxide injury
to plant life, and the application of remedial measures,
whicH include use of high stacks and high temperature*
for the discharge of waste gasoa, continuous automatic
measurement of ground concentrations and application
of meteorological control by accurate forecasting of critical
weather conditions, and installation of recovery plants
for conversion of excess sulfur dioxide to Ucruid sulfur
dioxide, sulfuric acid, fertilizers, or elemental sulfur.
The annual losses of sulfur from products discharged to
the atmosphere from zinc plants, lead, copper, and nickel
smelters, crude oil refineries, and from coal combustion,
are compared with world native suHur production and
fay-product sulfur recovery. The extent to which, aulfur
emission must ba reduced, to avoid injury to plant life,
is discussed in terms of the permissible levels o£ ground
concentration. Methods for recovery of sulfur com-
pounds from sulfur dioxide and hydrogen eulfide in stack
gas include concentration of sulfur dioxide and its con-
version to sulfuric acid, recovery a« elemental aulfur, and
flue gas disposal of the effluent and noneffluent types.
New developments of outstanding importance for puri-
fication and recovery of sulfur dioxide are embodied
in the Trail ammonia process, the dimethylaniline process
•tSelfcy, ahS Rash smelting at Copper~C!ifi in conjunction
with liquid sulfur dioxide recovery. An aroused public
consciousness of the need of controlling atmospheric ,
pollution has stimulated investigation in many contaml-
nated areas. SuHur contaminants may ba profitably re-
covered In many industrial operations and thus clean up
the air and add to native aulfur reservos, which are rapidly
being depleted in tho United States. More research u
needed in industries confronted with difficult recovery
problems—for example, nickel Bmeltern. Cooperation
between major native sulfur producers and companies
•with a large sulfur problem on their hands is desirable.
SULFUR compounds have been recognized as major ;dii«.
plierlc contaminants for mnny years in the metal sincltini!
Bnd oil refining industries, and in all operations involving tlw
consumption of large quantities of sulfur-containing fuels such n."
coal. Enormous damage has been caused by tho excessive emis-
sion and wastage of such products to agricultural and forest ttrcn.?,
and to materials such as nietnls, atone, cement, paint, pupcr,
leather, and textiles. The nnnunl Infwes from nir pollution cannot
be assessed accurately but, nevertheless, nnmunt to man)
millions of dollars. If one considers (hat, a suhstnnt.irJ portion of
tho sulfur dioxide or hydrogen Biilfide lost to the atmosphere
may be economically recovered, the, real magnitude o( such taws
and the importance of tide problem l»ceoine apparent.
Within the. past 20 years a great scientific effort has Ixwn mad*
in the United Stales, Canada, and elsewhere to determine tlw
causes of air pollution and to develop tcelimcal methods of con-
trol. Tho effect of sulfur dioxide on plant life and metabolism,
IilKitosyritheaia and respiration, and the factors affecting suscep-
tibility have been evaluated with scientific accuracy. Consider-
. able insight has been gained into tho role of nucromoteorology
and the influence of topography on smog conditions aecom-
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TECHNICAL REPORT DATA
(Please read Inunctions on the reverse before completing)
1. REPORT NO.
EPA-600/2-76-036k
4. TITLE AND SUBTITLE
Design and Operating Parameters for Emission •
Control Studies; ASARCO, Tacoma, Copper Smelter
5. REPORT DATE
February 1976
6, PERFORMING ORGANIZATION CODE
J, AUTHOR(S)
I. J. Weisenberg and J. C. Serne
B. PERFORMING ORGANIZATION REPORT NO.
3. RECIPIENT'S ACCESSION-NO.
9. PERFORMING ORG '\NIZATION NAME AND ADDRESS
Pacific Environmental Services, Inc.
1930 14th Street
Santa Monica, CA 90404
10. PBOORAM ELEMENT NO.
1AB013; ROAP 21ADC-061
11. CONTRACT/GRANT NO.
68-02-1405, TaskS
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 AND PERIOD COVERED
Task Final; 4-10/75
14. SPONSORINQ AGENCY CODE
EPA-GRD
15. SUPPLEMENTARY NOTES
EPA Task Officer for this report is R.Rovang, 919/549-8411, Ext 2557.
is. ABSTRACT
repOr^ gives background design data for a specific copper smelter,
The data is sufficiently detailed to allow air pollution control system engineering
studies to be conducted. These studies will be concerned primarily with lean SO2
streams that currently are not being captured. Physical layout of the smelter and
the surrounding area is presented, along with existing control equipment. Ductwork
that would be considered for future system tie-in is defined. Emissions from
operating equipment, gas flow rates, temperatures, sulfur balance, and a process
flow sheet are included. Utilities , stack dimensions , footing requirements , and
solid waste handling are defined. Available area for new control equipment, gas
characteristic variation, and potential new control equipment installation
problems are discussed.
17.
KEV WORDS AND DOCUMENT ANALYSIS
DESCRIPTORS
b.lDENTIFIERS/OPEN ENDED TERMS C, CCSATI Field/Group
Air Pollution
Copper
Smelters
Design
Sulfur Dioxide
Utilities
Air Pollution Control
Stationary Sources
Emission Control
Operating Data
Solid Waste Handling
Wastes
13 B
07B
11F
18. DISTRIBUTION STATEMENT
Unlimited
19. SECURITY CLASS (ThisReport)
Unclassified
[21. Up. OJ= PAGES
\L
2O. SECURITY CLASS (Thispage)
Unclassified
EPA Form 2220-1 {9-73}
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