SCREENING STUDY FOR BACKGROUND
INFORMATION AND SIGNIFICANT EMISSIONS
FROM GYPSUM PRODUCT MANUFACTURING
TASK ORDER NO. 14
CONTRACT NO. 68-02-0242
PREPARED FOR
CONTROL SYSTEMS DIVISION
ENVIRONMENTAL PROTECTION AGENCY
SUBMITTED BY
PROCESSES RESEARCH, INC.
INDUSTRIAL PLANNING AND RESEARCH
CINCINNATI, OHIO
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PROCESSES RESEARCH, INC.
INDUSTRIAL PLANNING AND RESEARCH
SCREENING STUDY FOR BACKGROUND
INFORMATION AND SIGNIFICANT EMISSIONS
FROM GYPSUM PRODUCT MANUFACTURING
Task Order No« 14
Contract No. 68-02-0242
May 25, 1973
Prepared for
Control Systems Division
Environmental Protection Agency
Submitted by
PROCESSES RESEARCH, INC.
Industrial Planning and Research
Cincinnati, Ohio
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PROCESSES RESEARCH, INC.
INDUSTRIAL PLANNING AND RESEARCH
This report was furnished to the Environmental Protection Agency by Processes
Research, Inc., Cincinnati, Ohio in fulfillment of Contract No. 68-02-0242. The
contents of this report are reproduced herein as received from Processes Research,
Inc. The opinions, findings, and conclusions expressed are those of the author
and not necessarily those of the Environmental Protection Agency.
ii
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PROCESSES RESEARCH, INC.
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ABSTRACT
The report deals with the atmospheric emissions that are produced during the
operation of calcining gypsum and production of gypsum board products. The aver-
age particulate emissions from these plants are between 25 and 40 pounds per hour
with baghouse collectors and electrostatic precipitators generally being employed
as control devices. Extrapolation of emissions from all plants indicate that total
emissions are in the range of 80,000 tons per year. Emission of sulfur oxides is
primarily dependent upon the sulfur content of the fuels being used for calcining
and other operations, and production of nitrogen oxides is also a function of the
combustion equipment and fuels used. Emission regulations relating to visible,
particulate, sulfur oxide, and nitrogen oxide emissions are shown for nine states
A description of a general process for production of calcined gypsum and gypsum
board products is given with flow diagrams. A list of gypsum and/or gypsum pro-
duct producers is shown along with total industry production capacity, best
controlled plants and their control equipment, and emissions data from various
production locations. A brief description of emission analysis, applicable con-
trol technology, and economics of control equipment is included.
iii
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PROCESSES RESEARCH, INC.
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Section
I
II
III
IV
V
VI
VII
VIII
IX
X
XI
SCREENING STUDY FOR BACKGROUND
INFORMATION AND SIGNIFICANT EMISSIONS
FROM GYPSUM PRODUCT MANUFACTURING
INDEX
Title
Purpose and Scope
Summary
Air Pollution Regulations
Calcining of Gypsum
Board Products
Emissions, Analysis and Control
List of Producers
Data from Operating Plants
Best Controlled Plants
Forecast of Growth
Information Sources
Page
1
2
3
13
19
22
31
35
41
42
43
iv
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SECTION I - PURPOSE AND SCOPE
This report provides the Control Systems Division, Environmental Protection
Agency, with preliminary qualitative and quantitative data related to the
operation of plants for the production of gypsum and gypsum products.
The general purposes of this preliminary study were to identify sources of
atmospheric emissions in this industry, to identify and quantify such emissions
and to evaluate the state of the art in terms of equipment currently employed for
the control of such emissions.
The scope of this preliminary report deals with the two major industry
operations:
A. Calcining of gypsum.
B. Production of board products.
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SECTION II - SUMMARY
Review of the emissions data contained in this report will disclose that
the "best controlled" gypsum calcining plants and board plants employ bag collec-
tors and/or electrostatic precipitators. The average particulate emissions for
these plants are in the range of 25 to 40 pounds per hour and these plants will
generally comply with existing air pollution regulations.
If all plants were so equipped, the total nationwide emissions of particu-
lates would be on the order of 12,000 tons per year.
Extrapolation of the data for all plants indicates that total emissions of
particulates to atmosphere are in the range of 80,000 tons per year.
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SECTION III - AIR POLLUTION REGULATIONS
Gypsum product plants are located in 28 states. Ten of these states have
been selected as representing a cross section of the areas in which these plants
are located.
A summary of the pertinent regulations of each of these states (with the
exception of California) is given below. In California, each county has its own
regulations and a county by county analysis of these regulations is not deemed
to be appropriate for this report.
The 10 states involved are:
California Michigan
Florida New Jersey
Georgia New York
Indiana Oklahoma
Iowa Texas
The regulations abstracted deal with:
1. Particulate Emissions from Process Sources.
2. Visible Emissions.
3. Emission of Nitrogen Oxides and Sulfur Oxides from Fuel Burning
Operations.
1. PARTICULATE EMISSIONS FROM PROCESS SOURCES
The allowable emission, in pounds per hour, is based on the process
weight rate. Process weight is defined as the total weight of all materials
introduced into any source operation. Solid fuels charged are considered as
part of the process weight, but liquid and gaseous fuels and combustion air are
not. The rate of allowable emission is shown in Table I.
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TABLE I
REGULATIONS APPLICABLE TO GENERAL PROCESS SOURCES
RATE OF ALLOWABLE EMISSION. LBS PARTICULATE/HR
Process Weight Rate, Lbs/Hr
Florida
Georgia*
Indiana
Iowa
Michigan
New Jersey'
New York3
Oklahoma
Texas
100
.55
.551
.551
.55
.55
.50
.551
..
1,000
2.25
2.58
2.58
2.58
2.58
2.3
2.58
1.6
5.000
6.34
7.58
7.58
7.58
7.58
6.7
7.58
7.7
10,000
9.73
12.0
12.0
12.0
12.0
10.8
12.0
15.2
20 ,000
14.99
19.2
19.2
19.2
19.2
17.4
19.2
30.1
40,000
23.0
30.5
30.5
30.5
30.5
27.6
30.5
59.7
60,000
29.60
40.0
40.0
40.0
40.0
36.1
40.0
67.4
120,000
33.28
46.3
46.3
46.3
46.3
51.8
46.3
82.3
200,000
36.11
51.2
51.2
51.2
51.2
56.1
51.2
95.2
1,000,000
46.72
69.0
69.0
69.0
69.0
71.7
69.0
151.2
2,000,000
--
77.6
77.6
77.6
77.6
78.3
77.6
184.4
6,000,000
—
92.7
92.7
92.7
92.7
90.24
92.7
252.3
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Notes for Table I
1. For new equipment only. For existing equipment the values are the
same through 60,000 pounds per hour. For over 60,000 pounds per hour, the
values are:
Process Weight Rate
Lbs/Hr
120,000
200,000
1,000,000
2,000,000
6,000,000
Allowable Emissions
Lbs/Hr
63.5
89.7
262.0
414.0
873.0
2. New Jersey does not follow this format. Their format is:
Allowable1*
Emission
Rate
Lbs/Hr
0.5
1.0
6.0
12.0
24.0
30.0
a. Based on 99 percent collection efficiency.
b. Based on 0.02 grains per scf.
3. Applies to sources with an environmental rating of B or C. Allowable
emission rate from sources with an A or D rating is at the discretion of the
Department of Environmental Conservation.
Potential Emission
Rate from Source
Operation
Lbs/Hr
50 or less
100
1,000
2,000
3,000 or more
Allowable*
Emission
Rate
Lbs/Hr
0.5
1.0
10.0
20.0
30.0
Source Gas
Emitted From
Source Operations
Scfm
3,000 or less
6,000
35,000
70,000
140,000
175,000 or more
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2. VISIBLE EMISSIONS
a_. Process Sources
These emissions are graded on the basis of equivalent opacity which
is the degree to which an emission, other than gray or black smoke, is partially
or wholly impervious to rays of light and causes obstruction of an observer's
view. This is expressed as an equivalent of the obstruction caused by a gray or
black smoke emission of a given density as measured by a Ringelmann Smoke Chart.
b_. Fuel Burning Operations
Opacity is determined by use of a Ringelmann Smoke Chart.
The Ringelmann Smoke Chart is published in the U. S. Bureau of
Mines Information Circular No. 8333.
The allowable opacities are shown in Table II.
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TABLE II
REGULATIONS APPLICABLE TO VISUAL EMISSIONS
State
Florida
Georgia
Indiana
Iowa
Michigan
New Jersey
New York
Oklahoma
Texas
PARTICULATES
Fuel Burning1
Percent Opacity
202
202
40
40
205
206
207
20
208
Industrial Processes
Percent Opacity
No visible discharges^
104
40
40
205
20
207
20
208
Notes for Table II
1. When presence of uncombined water is the only reason for failure of
emissions to meet limitation, these requirements do not apply.
2. For new equipment; 40 percent for existing equipment.
3. For sulfuric acid plants and nitric acid plants. Other plants not
specified.
4. For new portland cement plants, new nitric acid plants, and new sul-
furic acid plants. Other plants not specified.
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5. Proposed rule change. Existing regulation calls for 40 percent.
6. Applies to indirect heat exchangers with a rated hourly capacity of
200 mm Btu or greater gross heat input. If input is less than 200 mm Btu, no
visible emissions are permitted.
7. May not exceed this value for more than 3 minutes out of any 60 minute
time period. May not exceed 40 percent during this 3 minute period.
8. For new .installations. Thirty percent for existing installations.
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3. EMISSION OF NITROGEN OXIDES AND SULFUR OXIDES FROM FUEL BURNING
OPERATIONS
The rate of allowable emission is shown in Table III. However, enforce-
ment of these regulations will undoubtedly be affected by the current uncertainty
in regard to the reliability of analyses for nitrogen oxides (see Section VI).
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Florida1
Georgia2
Indiana
Iowa
Michigan
New Jersey
New York
Oklahoma
Texas
14
TABLE III
EMISSION OF NITROGEN OXIDES AND SULFUR OXIDES
Nitrogen Oxides
Lbs/MM Btu Heat Input
Liquid
Fuel
0.30
0.30
0.303
0.306
0.3011
0.30
(As N02)
Solid
Fuel
0.70
0.70
0.703
See Note 7
See Note 9
0.7011
0.70
See Note IS
FROM FUEL BURNING OPERATIONS
Sulfur Oxides
Lbs/MM 'Btu Heat Input
Gaseous
Fuel
0.20
0.20
0.203
0.206
0.2011
0.20
(As S02)
Liquid Solid
Fuel Fuel
0.80 1.20
0.80 1.20
See Note 4
1.55 5.05
See Note 8
See Note 10
See Note 12
0.813 2.0
See Note 16
Gaseous
Fuel
•-_•
0.20
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Notes for Table III
1. New sources, maximum 2 hour average. All sources after July 1, 1975.
2. New sources. For existing sources:
S = 4000F/L^s_\ "
^300 /
Where S = S02 emitted, Ibs/hr
hg = Stack height, ft
n =» 3 for hs < 300
n = 2 for h ^-300
S
f Varies from 0.8 to 3.0 depending upon heat input and
location of source.
3. For fuel burning equipment with a capacity of 250 mm Btu/hr or more.
4. Sulfur dioxide emission for new sources with a heat input of more
than 250 mm Btu/hr shall comply with the Federal emission standards. For new
sources with a heat input of 250 mm Btu/hr or less, and for existing equipment,
the emission rate shall be limited to that expressed by:
-0.33
Em * 17.0 Qrn
Where Em = Maximum allowable SC^in the stack gases in Ibs/mm Btu
heat input
Qm = Heat input, mm Btu/hr
5. Maximum 2 hour average after January 1, 1975. From January 1, 1974 to
January 1, 1975, the limits are 2.0 for liquid fuels and 6.0 for solid fuels.
6. Maximum 2 hour average, effective January 1, 1974.
7. No limits stated.
8. Limitations apply to steam generating stations only.
9. No limits stated.
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10. Very involved method used for determining allowable S02 emission.
See New Jersey Air Pollution Control Code, Chapter 8, Sections 2.2, 2.3, and
2.17.
11. Applies to installations with a heat input of more than 250 mm Btu/hr.
12. Limitations are placed on sulfur content of fuel rather than on
emissions.
13. After July 1, 1975, limit is 0.3 Ibs/mm Btu.
14. All figures are based on a maximum 2 hour average.
15. Limitations apply to gas-fired steam generating units only.
16. For fuel burning units other than steam generators, limitations are
based on ground level concentration averaged over a 30 minute period. They are:
Galveston and Harris Counties - 0.28 ppm
Jefferson and Orange Counties - 0.32 ppm
Other counties - 0.40 ppm
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SECTION IV - CALCINING OF GYPSUM
For the manufacture of gypsum products, the gypsum must be converted from
calcium sulfate dihydrate (CaSO^ZI^O) to calcium sulfate hemihydrate
(CaSO^»l/2H20) by calcining under controlled temperature conditions so that
calcium sulfate anhydrite (CaSO^) is not produced. Strictly speaking, the term
"gypsum" refers only to the dihydrate, but the term is almost universally used
in referring to the hemihydrate and anhydrite as well. Block flow diagram
No. 3411-A shows the relationship between steps in the process and composition
of the gypsum.
Gypsum is mined in both open pit and underground mines. Calcining plants
are located near these mines or along a seaboard,or major waterway if imported
gypsum is used. The run-of-mine gypsum is reduced in size and free water re-
moved before calcining to remove the combined water. Referring to flow diagram
No. 3411-B, a brief description of the process iis:
v Run-of-mine gypsum is conveyed to a crusher feed bin. From this bin it
passes over a vibrating screen to a crusher. The underflow from the screen and
the discharge from the crusher are combined and conveyed to a crushed rock
hopper. A portion of this material may be screened to provide the proper size
rock to be sold for use as a Portland cement retarder. Rock from the hopper is
fed to a surge bin from which it flows (or is conveyed) to a grinding mill.
This mill is usually a Raymond type which grinds, classifies, and dries the rock.
When calcining or drying gypsum, the mill is in a circuit in which the solid is
subjected to hot gases during grinding. In this setup, the mill fan draws hot
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PROCESSES RESEARCH, INC.
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combustion gases through a flue from a furnace. From the mill the hot dust-laden
gases exit through a duct to a cyclone collector, from which the finished product
drops to a bin while any remaining dust is removed by a baghouse collector. The
hot combustion gases are exhausted by a fan from the bag collector with part of
the gas being recycled to the furnace. This is shown on flow diagram No. 3411-B1.
The ground rock from the mill (80 percent O-OO mesh) is known as "land plaster"
and may be sold as such for agricultural purposes. This material is conveyed to
the land plaster bins which feed the calciners when further treatment is required„
Calcining is usually done batchwise in vertical kettles until the tempera-
ture of the mass reaches a maximum of 320 to 340F. The calcined materials, known
as "hot stucco" is then dropped to the hot pits. The stucco is then conveyed to
stucco storage bins. Improperly calcined material may be conveyed to the stucco
reject bin from where it is recycled back to the crushed rock storage bin. In
some plants, continuous calcining is carried out in a Raymond mill. This simul-
taneously crushes, classifies, removes the surface moisture, and calcines the
gypsum.
The finished stucco may be sold as such for use in various plasters, Keene's
cement, etc. It is also the major raw material for a board products plant. If
such a plant is built in conjunction with a calcining plant, the stucco is con-
veyed to the feed bins of the board plant.
The only air pollutants from this process are gypsum dust and stack gases
from the heaters for the Raymond mills and from the calciners. The fuel used
for the heaters and calciners may be gas or oil. If oil is used there may be
SOX and NOX emissions.
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PROCESSES RESEARCH, INC.
CINCINNATI, OHIO
NEW YORK, N.Y.
DRWG. 34II-A
GYPSUM
RCCK
CASQq
•2H20
PARTICIPATE
PARTICULATE
CRUSHING
PARTICULATE -
PLASTERS
&CEMENTS
SCREENING
GRINDING
DRYING
(FREE WATER!
ONLY) i
PORTLAND
CEMENT
RETARDER
CASCV2H20
-PARTICULATE
LAND
PLASTER
CAS04-2H20
AGRICULTURAL
GYPSUM
-2H20
CALCINING
PARTICULATE
SOX,NOX
STUCCO
CAS04-'4H20
BOARD
PRODUCTS
PRODUCT BLOCK FLOW DIAGRAM
15
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RUN-OF-
MINE ROCK
HOPPER
CRUSHER
FEED
BIN
V
^
SCREEN
TO ATM
I
II SCREENJV
CEMENT ROCK
\/
SURGE
TANK
CRUSHED
ROCK
STORAGE
BIN
^
D
^
7i
if
1
?
s
LAND
PLASTER
BIN
fx
\
Si
s.
'v
/
— ... .... , >
STUCCO
REJECT
BIN
ELECTROSTATIC
PKECI PITATOR
1-
/I'TO ATM
r
i IT
RAYMOND MILL
CALCINER
HOT
PIT
TO BOARD
PLANT
^^-""^^
CEMENT
ROCK
LOADING
TYPICAL GYPSUM PRODUCTS PLANT
CRUSHING,- MILLING, AND CALCINING
DRWG. 3411-B
PROCESSES RESEARCH, INC.
CINCINNATI, OHIO NEW YORK, N.Y.
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EXHAUST
GASES
RECYCLED
GASES
RAYMOND
MILL
FURNACE
MAKE-UP
AIR
FAN
17
DRWG34II-BI
PROCESSES RESEARCH, INC.
CINCINNATI, OHIO
NEW YORK, N.Y.
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The major sources of emission and types of pollutants are:
Source Pollutant
Primary crusher Dust
Crushed rock screen Dust
Crushed rock bin Dust
Crushed rock feeder Dust
Grinding mill
Gas fired Dust
Oil fired Dust
S02
NOX
Calciners
Gas fired Dust
Oil fired Dust
S02
NOX
Land plaster bin Dust
Stucco reject elevator Dust
Emissions from the grinding mill, land plaster bin, calciners, and stucco
reject elevator may be too hot to be sent to a baghouse and the dust is too fine
to be collected efficiently in a cyclone. Therefore, they are usually conveyed
to an electrostatic precipitator. If the calciners and grinding mill heaters
are oil fired, the exhaust gases from the precipitator may have to be scrubbed
to bring the S02 down to acceptable levels.
The dust from the primary crushing and screening operations is usually
collected in cyclone units. It is usually necessary to supplement these with
baghouse units or a precipitator for additional cleanup«
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SECTION V - BOARD PRODUCTS
In manufacturing board products from gypsum, water ±s mixed with the stucco
and various materials are added to impart the required properties to the finished
product. The nature of these additives will vary, depending upon whether the
finished product is wallboard, acoustical board, insulating board, etc. A
typical process for making wallboard is shown on flow Diagram 3411-C. Referring
to this flow diagram, a brief description of the process is:
Stucco from the hot pits is conveyed to the stucco storage bins in the board
plant. No attempt is made to cool this stucco since the elevated temperature
will not affect the process adversely. The stucco is conveyed by a screw con-
veyor to an elevator and discharged to a vibrating screen. Any agglomerates
which may have formed are screened out and returned to the screw conveyor where
the shearing action of the conveyor will break them up. The underflow from the
screen flows to a transfer conveyor. Various additivies such as starch, vermicu-
lite, chopped glass fiber, and ground scrap are also added in this conveyor.
This mixture is conveyed to a mixer where foamed soap from a foam generator and
a mixture of asphalt, potash, and water from a Hydrapulper are also added. This
material is thoroughly mixed to form a thick slurry, or paste, which is fed to
the board machine.
In the board machine the paste is fed uniformly onto a liner paper. A top
paper liner is applied under a pair of nip rolls and edge folders. This sand-
wich is then conveyed on a flat belt conveyor until the core hardens - usually
about 6 minutes. The board is then cut automatically by a revolving knife.
19
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N>
O
TO ATM
BAGHOUSE
UJ
O
V
1
MANUAL
"S
r
S
<\
a:\
0
x
cc
\
SOAP
SOLUTI.OJ
GLASS FIBER
ROVING CUTTER
: _£_
TO WASTECTRUCK)
»LATH TO STOkAGE
ABOARD TO STORAGE
DRYER
CUT OFF
KNIFE
BOARD MACHINE
TYPICAL GYPSUM PRODUCTS PLANT
BOARD AND LATH PRODUCTION
PAPER
FEEDER
DRWG. 34II-C
PROCESSES RESEARCH, INC.
CINCINNATI, OHIO
NEW YORK, N.Y.
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The cut boards are automatically turned over and passed through a long, four-
section kiln dryer. The boards leaving the dryer are turned face to face and
end sawed to give smooth, straight ends. They are then bundled and stacked in
preparation for shipping or warehousing.
With minor modifications in operations, lath and sheathing can be made on
the same equipment. The process is the same as described for wallboard.
The only air pollutants from this process are gypsum dust and wallboard
dust, which are essentially the same thing. Dusts from the stucco handling
system, the additives elevator, and the mixer, go directly to a baghouse. Dust
from the board-forming machine goes to a cyclone collector. The solids from
this collector flow to the Hydrapulper and the air goes to the baghouse. Solids
from the baghouse are recycled to the stucco feed screw.
Dust from the end saws goes to a cyclone or baghouse collector. The
collected dust may be recycled as an additive or may be discarded. Air from the
collector is discharged to the atmosphere.
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SECTION VI - EMISSIONS, ANALYSIS AND CONTROL
A. ANALYSIS
The determination of the quantity of emissions from a gypsum products
plant is facilitated by the fact that most emissions are carried in airstreams
which are moved by blowers. Few natural draft stacks are involved. These
blowers are usually used as exhausters on the downstream side of dust collection
equipment.
The most accurate method in general use to determine the quantity of
air moved by a blower is a duct traverse using a standard pitot tube (Ref. 3b).
Frequently it is possible to make a close approximation of the flow rate by
measuring the operating horsepower of the blower and the differential head across
the blower. The flow rate can be found from the performance curve. The accuracy
will depend on the characteristic curve for the blower.
The determination of the quantity of particulate matter carried in any
stream is best made by passing a known quantity of the stream through a flash-
fired glass fiber filter which is weighed before and after the sample is taken
(Ref. 3b). The highest temperature of any of these streams from a gypsum plant
is below the temperature limit of the filters and filter holders available.
In making these determinations, it is important that isokinetic sampling tech-
niques are used.
Since the only S02 which will be emitted from a gypsum plant will be
from a combustion process using oil, the simplest way to determine it is to
analyze the oil for sulfur content. All of this sulfur will be converted to
S02 so the total emission of SO2 will depend on the firing rate.
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The problem of measuring nitrogen oxides, especially in the presence
of sulfur oxides, is being extensively studied by many organizations. None of
the methods now available give completely satisfactory results (Ref. 3b, 4 and
5). However, some of the newer methods seem promising. One of these is the
electrochemical sensor equipped to determine both S0£ and NOX. In this unit,
the 802 is not differentiated by the NOX sensor but the NOX does not interfere
with the SO2 sensor. Both sensors are used and the NOX measurement is corrected
to allow for the S0£ level. In using this method the sample must be filtered
and cooled. This could be done in conjunction with the test for particulate
matter.
In a properly fired unit, carbon monoxide should not be present in the
outlet gases. It is the only one of the fixed gases which is a pollutant. The
classical procedure for measuring it is to pass the gas sample over hot iodine
pentoxide and titrate the iodine liberated. Carbon monoxide is also measured
by gas chromatography and by nondispersive infrared (NDIR) analyzers. The NDIR
analyzers have rapid response and good sensitivity but tend to drift so that
fairly frequent zeroing and calibration may be necessary. All of these methods
require that the sample be filtered and cooled.
In discussion with gypsum manufacturers in the United States, it has
been determined that no fluorine bearing gypsum (byproduct of phosphoric acid
manufacture) is used to produce commercial gypsum, wall board, .and associated
products. Therefore, in regard to the gypsum industry, emissions of fluorines
and fluorides are not considered to be a problem.
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B. CONTROL
The best way to control 802 is to use a low sulfur fuel. If this is
not feasible the S02 may be removed from the stack gas by wet scrubbing» One
system uses a lime slurry which reacts with the S02 to form sulfates and sul-
fites (Ref. 3a). This, of course, precludes recovery of the SQ2. Another
systems uses a hot solution of potassium sulfite (1^803) for scrubbing (Ref. 3a) .
The sulfite reacts with 802 to form potassium bisulfite. Cooling the hot bi-
sulfite solution converts the bisulfite (KHS03> to the pyrosulfite (1^8205) which
is concentrated and steam stripped to produce 802 an<^ potassium sulfite. The
latter is reused in the scrubber. This system requires close temperature control
and uses about four pounds of steam for each pound of 802 recovered.
The reduction of nitrogen oxides to less than 200 ppm in an effluent
stream is very difficult. Much of the current technology involves scrubbing with
alkaline solutions but this is of limited value because of the low solubility of
nitrogen oxides in water (Ref. 3a). This problem is also being extensively in-
vestigated by several organizations.
The most efficient equipment for the collection of particulate matter
is the electrostatic precipitator. It is also the most expensive and is used in
gypsum plants only when the effluent is too hot to be collected in a baghouse.
The use of cyclone collectors and baghouses should be satisfactory if proper
units are chosen for the various services. Wet collectors are usually avoided
since they convert an air pollution problem to a water pollution problem.
Both baghouse collectors and electrostatic precipitators used to collect
gypsum dust have collection efficiencies of 95 to 99 percent. The cost information
relating to these two types of equipment are presented in the following tables.
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PROCESSES RESEARCH, INC.
INDUSTRIAL PLANNING AND RESEARCH
TABLE IV
BAGHOUSE COLLECTOR
Rate: 40,000 acfm
Costs:
FOB (including fan, starter, and 40 horsepower motor) $40,000
Erected $50,000
Operating per year $ 3,200
Maintenance per year $ 8,000
Capital (12.8 percent of erected cost) $ 6,400
Total annual cost $17,600
Sources: "Estimating the Cost of Gas Cleaning Plants" Chemical
Engineering, December 13, 1971, Pg 86-96.
"A Manual of Electrostatic Precipitator Technology - Part II -
Application Areas." NATIC No. PB-196-381
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Table V
Electrostatic Precipitator Installations in Gypsum Plants
(Period 1935-1969)
Pptr. Contract
Year (s)
1935-1939
1940-1944
1945-1949
1950-1954
1955-1959
1960-1964
1965-1969
Five (5)
No. of
Install.
4
3
3
18
20
10
1
Year Period Indicated
No. of
Pptrs.
5
3
3
25
21
11
2
Total Gas
Volume
(ICfacfm)
100
56
77.5
545.5
607.6
351.6
80
Average Volume /Year
During Period
(10 acfm)
20
11.2
15.5
109
121.5
70.3
16.0
Weighted Design
Efficiency on acfm
Basis (%)
98.5
98.6
96.5
97.5
97.7
99. 15
99.0
Grand Totals
59
70
1818.2
NOTES: The statistics in this table include precipitators on rock dryers,
kettles, rotary calciners, holoflite calciners, and combinations
of calciners and kettles with dryer and grinding mill vent gases.
26
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Table VI
Summary of Performance Data on Gypsum Plant Electrostatic Precipitators
Calciner Calciner Combination
Kettles Rock Dryers (Rotary) (Holoflite) . Kettle, Dryer, Mill
Critical Parameter Max Min Max Min Max Min Max Min Max Min
1. Gas Volume/Precipitator 13.6 2.9 43.0 10.8 82.5 29.8 16.6 7.6 60.2 9.0
(acfm in thousands)
2. Precipitator Efficiency 99.90 94.38 99.85 97.2099.82 99.14 99.90 98.20 99.96 93.76
(per cent)
3. Gas Velocity in Precipitator 5.5 1.5 7.5 3.1 7.9 4.2 2.8 1.4 7.4 3.0
(fps)
•VJ
4. Precipitator Dust Concentration 48.0 4.8 156 4.6 46.3 32.9 62.6 30.8 63.9 7.7
; (gr/scfd)
5. Precipitator Input Power 828 124 282 69 174 62 983 576 390 65
(watts/1000 acfm)
6. Precipitator Avg. Field 12.8 8.8 15.0 9.0 13.0 8.1 15.5 9.8 13.4 8.0
Strength (kV/in.)
7. Gas Moisture 47.6 19.0 17.4 3.6 35.2 14.2 54.0 17.6 22.2 6.7
(per cent by volume)
8. Gas Temperature 342 220 240 125 - 339 200 250 140
(°F)
9. Precipitator Performance 2.39 0.74 2.06 0.89 1.45 1.03 1.39 0.47 2.39 0.40
Ratio (R)
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PROCESSES RESEARCH, INC.
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Economics. Table VII shows erected and FOB costs for precipitators installed
in gypsum plants over the period 1959-1967. The costs per acfm range from $0.89
to $1.03 for 99.0% collection efficiency, and from $1.43 to $1.53 for 99.5%.
Erected costs vary from $1.38 to $3.62 per acfm.
Table VIII lists the maintenance costs for two precipitators installed in
gypsum plants. The fan costs were based on a pressure drop of 1/2" W.G. in the
precipitator. The plant was assumed to operate 8000 hours per year with elec-
tricity costs estimated at $0.0075 per kWh.
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PROCESSES RESEARCH, INC.
INDUSTRIAL PLANNING AND RESEARCH
Table VII
Gypsum Industry Economics
Year
1959
1960
1961
1962
1964
1965
1967
Type
Cost
FOB
Erected
FOB
Erected
FOB
FOB
Erected
FOB
Design Design Total Cost/Unit Volume
Volume Efficiency Cost ($ /acfm)
(1000'sacfm) (%) (10? $)
40
40
40
40
40
36
36
36
40
27
40
99.0
99.0
99.0
99.7
99.0
99.5
99.5
99.5
99.0
99.0
99.0
39.5
55.2
38.7
90.1
35.7
55.0
51.3
56.3
36.0
97.8
41.0
0.99
1,38
0.97
2.25
0.89
1.53
1.43
1.57
0.90
3.62
1.03
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PROCESSES RESEARCH, Lsrc.
INDUSTRIAL PLANNING AND RESEARCH
Table VIII
Maintenance Data for Precipitators
Installed on Gypsum Calciners
Prod. Rate tons/hr. 17-17 60-90
Gas Flow, acfm 16,600 35,000
Precipitator Power, kW 12.2 13.5
No. of Maintenance Periods/year 3-4 3-4
Man hours/year 70-90 70-90
Maintenance Labor Costs 480 480
Fan Power, kW 2 1. 04 2.19
Power Costs - Fan, $/yr. 62.25 131.25
Power Costs - Precipitator, $ /yr. 730 810
Capital Costs,4 $/yr. 8,600 9,350
Total Annual Costs 9. 872. 25 10, 771. 25
i
Based on $6. 00 per hour
Based on 1/2" W. G. pressure drop
Based on Power Costs at $0. 0075 per kWh
Based on 12. 8% of total Erected Costs
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PROCESSES RESEARCH, INC.
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SECTION VII - LIST OF PRODUCERS
Gypsum and/or gypsum products are produced in twenty-eight of the conter-
minous states at 79 locations. Six major producers account for sixty-nine, or
87-1/2 percent, of these installations. There is no breakdown available showing
the nominal capacity or production for any of these producers. However, the
latest data (1971) available for the overall industry shows this breakdown
(Ref. 6):
Product Capacity
Uncalcined Short Tons
Portland cement retarder 3,349,018
Agricultural gypsum 849,970
Fillers and unclassified 106,003
Total 4,304,991
Calcined Plasters
Building Plasters
Regular basecoat 381,471
Mill-mixed basecoat 188,556
Veneer plaster 89,723
Gouging, molding, and Keene's cement 75,251
Roof-deck concrete 180.803
Total 915,804
Industrial Plasters 268,212
Board Products .MSF
Lath 477,403
Veneer base 292,257
Gypsum sheathing 272,269
Regular gypsum board 9,014,908
Type X gypsum board 1,766,483
Predecorated wallboard 122,361
Total (MSF) 11,945,681
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PROCESSES RESEARCH, INC.
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If all of the board products averaged out at 1/2 inch thickness, which gives
a weight of 2 pounds per square foot, the tonnage of board products is the same
as the thousands of square feet produced. Using this assumption, the total ton-
nage of gypsum and gypsum products produced in 1971 is 17,434,688 short tons.
This is in close agreement with the apparent supply of crude gypsum which was
estimated at 16,688,235 short tons (including imports) in 1971 (Ref» 6).
The seven major producers and the location of their installations are:
Company
The Celotex Corporation
The Flintkote Company
Georgia-Pacific Corporation
Gypsum Division
Johns-Manville Corporation
Kaiser Cement and Gypsum Corp,
State
Iowa
New Jersey
Ohio
Texas
Wyoming
California
Georgia
Nevada
New Jersey
Texas
Delaware
Georgia
Iowa
Kansas
Michigan
New York
Texas
Utah
Wyoming
Nevada
Arizona
California
Florida
New Jersey
Washington
City
Fort Dodge
Edgewater
Port Clinton
Hamlin
Cody
Fremont
Savannah
Las Vegas
Camden
Sweetwater
Wilmington
Brunswick
Fort Dodge
Blue Rapids
Grand Rapids
Akron
Buchanan
Quanah
Sigurd
Lovell
Las Vegas
Florence
Antioch
Long Beach
Jacksonville
Delanco
Seattle
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Company
National Gypsum Company
United States Gypsum Company
State
Arizona
California
Connecticut
Florida
Georgia
Illinois
Indiana
Iowa
Kansas
Louisiana
Maryland
Michigan
New Hampshire
New Jersey
New York
Ohio
Texas
California
Florida
Indiana
Iowa
Louisiana
Maryland
Massachusetts
Michigan
Montana
Nevada
New York
Ohio
Oklahoma
Pennsylvania
Texas
Utah
Virginia
City
Phoenix
Long Beach
Richmond
New Haven
Tampa
Garden City
Waukegan
Shoals
Fort Dodge
Medicine Lodge
Westwego
Baltimore
National City
Portsmouth
Burlington
Bronx
Clarence Center
Lorain
Rotan
Plaster City
Santa Fe Springs
Jacksonville
East Chicago
Shoals
Fort Dodge
Sperry
New Orleans
Baltimore
Boston
Alabaster
River Rouge
Lewistown
Empire
New Brighton (S.I.)
Oakfield
Stony Point
Gypsum
Southard
Philadelphia
Galena Park
Sweetwater
Sigurd
Norfolk
Saltville
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PROCESSES RESEARCH, INC.
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Of the 81 installations, 46 (or 56.8 percent) are located in, or very close
to, standard metropolitan statistical areas. These include:
East Coast 21
Gulf Coast 4
West Coast 7
Fort Dodge, Iowa 4
East Chicago,
Indiana 1
Buffalo, New
York 3
Sandusky, Ohio 2
Sweetwater, Texas 4
46
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SECTION VIII -DATA FROM OPERATING PLANTS
The data shown in Tables IX and X were obtained from the plants indicated.
35
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TABLE IX
EMISSIONS FROM CALCINING OPERATIONS
PLANT DATA
Date
Company and Location Constructed
Celotex Corp.
Cody, Wyoming 1962
Edgewater, New Jersey 1958
Fort Dodge, Iowa 1958
Hamlin, Texas cas 1945
Port Clinton, Ohio ca. 1945
The Flintkote Co.
Fremont, California 1965
Savannah, Georgia 1964
Georgia-Pacific Corp.
Buchanan, New York 1969
Level1, Wyoming 1967
Grand Rapids Gypsum Co.
Grand Rapids, Michigan 1970'
Johns-Manvllle Corp.
Florence, Arizona 1955
Las Vegas, Nevada 1965
Kaiser Gypsum Co.
Jacksonville, Florida 1964
Delanco, New Jersey 1966
National Gypsum Co.
Richmond, California 1964
Fort Dodge, Iowa 1940
Clarence Center, New York 1940
Long Beach, California 1965
United States Gypsum Co.
Shoals, Indiana 1955
Stony Point, New York 1956
Baltimore. Maryland 1962
Dust Emission. Lbs/Hr
Total
40
40
40
400
35
.02 Grains
Per scf
0.5
0.84
0.56
35
0.2
4.3
45.5
45
0.45
7.6
12.6
0.9
5307
,96
5.11
Dust Collection Equip.
Fuel Burning
S02
Emission
Lbs/Hr
Note 1
Note 1
Note 1
Note 1
Note 1
Negl.
Negl.
Negl.
Negl.
Negl.
Negl.
Negl.
1.33
Note 5
0
0
(61) 6
0
Negl.
Negl.
Negl.
N°x
Emission
Negl.
Negl.
Negl.
Negl.
Negl.
Negl.
Note 4
Note 4
Negl.
Negl.
Negl.
Negl.
Negl.
Negl.
Negl.
Fuel
Used
Note 1
Note 1
Note 1
Note 1
Note 1
Gas2
Gas
Gas
Gas
Gas
Gas
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Notes for Table IX
1. S(>2 from low sulfur fuel meets. Federal standards.
2. No. 2 fule oil standby.
3. Also use a wet scrubber.
4. Unknown.
5. Unknown. Low sulfur fuel is used.
6. Quantity reported as 250 tons per year. Quantity shown is calculated
using 8160 operating hours per year.
7. Board plant built in 1920.
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TABLE X
EMISSIONS FROM BOARD PLANT OPERATIONS
Company and Location
Celotex Corp.
Cody, Wyoming
Edgewater, New Jersey
Fort Dodge, Iowa
Hamlln, Texas
Fort Clinton, Ohio
The Fllntkote Co.
Freemont, California
Savannah, Georgia
Georgia-Pacific Corp.
Buchanan, New York
Love11, Wyoming
Grand Rapids Gypsum Co.
Grand Raplda, Michigan
Kaiser Gypsum Co.
Jacksonville, Florida
Delanco, New Jersey
National Gypsum Co.
Richmond, California
Fort Dodge, Iowa
Clarence Center, New York
Long Beach, California
United States Gypsum Co.
Shoals, Indiana
Stony Point, New York
Baltimore, Maryland
Paper
Dust
.01
.01
15.4
Dust Emission. Lbs/Hr
End Trim Board
Dust Drying Total
30
5
5
30
Note 1
Note 3
0.5
.18 .19
.18 .19
5
33.3
14
2.8
2.6
2.1
2.9
3.6 19
12.8
9.9
Dust Collection Equip.
Cyclones Baghouse . P
X
X
X
X
Note 2
X
X
X
X
X5
X
X
X X
X X
X X
X X
X X
X X
X X
Fuel Burning
SC7 NOx
Emission Emission
Lbs/Hr^ Lbs/
Negl.
Negl.
Negl.
Negl.
Negl.
Negl.
Negl.
Negl.
Negl.
Negl.
12.5
Negl.
Negl.
Negl.
(94.4)'
Negl.
Negl.
Negl.
Negl.
Negl.
Negl.
Negl.
Negl.
Negl.
Negl.
Negl.
Negl.
Negl.
Negl.
Note 6
Negl.
Negl.
Negl.
Negl.
Negl.
Negl.
Negl.
Negl.
Gas
Gas
Gas
Gas
Gas
Gas*
Gas"
Gas
Gas
Gas
Gas
Gas
Gas"
Gas4
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PROCESSES RESEARCH, INC.
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Notes for Table X
1. None reported.
2. Closed system.
3. 99 percent of particles greater than 0.5 microns collected.
4. No. 2 fuel oil standby.
5. Also use a wet scrubber.
6. Quantity of NOX emission unknown.
7. Quantity reported as 340 tons per year. Quantity shown is calculated
using 7200 operating hours per year.
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PROCESSES RESEARCH, INC.
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A rough estimate of nationwide particulate contamination from gypsum
product plants can be made by using an average dust emission figure. From the
data available this is 340 Ibs/hr for crushing, grinding, and calcining oper-
ations, and 10.3 Ibs/hr for board plants. An average board line will produce
400 square feet per minute, or
4000*40) 365 . 210j2M mf per yMr
Since approximately 12,000,000 MSF per year are produced (see Section VII), the
total emission for board lines is
(1°'3) = 588 Ibs Per hour nationwide.
The total quantity of gypsum processed is approximately 17,500,000 tons
per year. The average plant will process about 1000 tons of rock per day.
Therefore, the approximate total emission for rock processing, is
\l>50°>0™ (340) - 16,300 Ibs per hour nationwide
3o!>
This is based on continuous three-shift operation.
If the mill is operated on a one-shift basis, the dust emission rate would
be three times this. Thus, the total dust emission rate could be as high as
49,500 pounds per hour on a nationwide basis.
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PROCESSES RESEARCH, INC.
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SECTION IX - BEST CONTROLLED PLANTS
The best controlled plants are the latest ones built, and are equipped
with baghouses or electrostatic precipitators or a combination of the two.
Among these are:
The Celotex Corporation Cody, Wyoming
The Flintkote Co. Savannagh, Georgia
Georgia-Pacific Corporation Buchanan, New York
Grand Rapids Gypsum Co. Grand Rapids, Michigan
Johns-Manville Corporation Florence, Arizona
Las Vegas, Nevada
Kaiser Gypsum Co. Delanco, New Jersey
National Gypsum Co. Long Beach, California
United States Gypsum Co. Baltimore, Maryland
The quantity of emissions for these plants and the type of control equip-
ment in use is shown in Tables IX and X.
A baghouse collector costs approximately five times as much as a comparable
cyclone collector. An electrostatic precipitator can be installed at a cost
comparable to a baghouse if the flow quantity is high. The minimum flow rate
for an industrial type precipitator is approximately 50,000 absolute cubic feet
per minute.
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PROCESSES RESEARCH, INC.
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SECTION X - FORECAST OF GROWTH
The demand for gypsum products is directly related to the housing industry.
For the past five years the domestic production of crude gypsum has leveled
off at 10 to 10.5 million short tons per year, with the balance of the crude
supplied as imports. Conceivably, this situation could continue for the next
few years and present gypsum producers attach a low probability to the possibility
of new gypsum plants in the short term.
Current indications of a rising trend in the housing industry could, however,
lead to expansion of existing plants or possibly to new gypsum board plants in
the near future.
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PROCESSES RESEARCH, INC.
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SECTION XI - INFORMATION SOURCES
COMPANIES AND ORGANIZATIONS CONTACTED
Celotex Corp.
1500 N. Dale Mabry
Tampa, Florida 33607
(813) 872-3111
Flintkote Co.
400 WestChester Ave0
White Plains, New York 10604
(914) 761-7400
Georgia-Pacific Corp.
900 S. W. Fifth Street
Portland, Oregon 97207
(503) 222-5561
Johns-Manville Corp.
Greenwood Plaza
Denver, Colorado
(303) 770-1000
Kaiser Gypsum Co.
300 Lakeside Drive
Oakland, California 94612
(415) 271-2211
National Gypsum Co.
325 Delaware Avenue
Buffalo, New York 14202
(716) 852-5880
United States Gypsum Co.
101 South Wacker Drive
Chicago, Illinois 60606
(312) 321-3400
The Gypsum Association
201 N. Wells Street
Chicago, Illinois 60606
(312) 726-5675
Grand Rapids Gypsum Co.
1007 N. Division Ave.
Grand Rapids, Michigan
(616) 459-6183
49501
Marion M. Hambrick
Vice President of Operations
J. E. Krebs
Project Engineer
Vincent J0 Tretter, Jr.
Senior Environmental
Engineer
Edmund M. Fenner
Director of Technical
Relations
Robert Costa
Vice President and General
Manager
W. A. Schmidt
Chief Dust Control Engineer
John F. Schroder
Manager of Environmental
Protection
F. J. Rogers
Manager, Administrative
Services
Not contacted. Data obtained
through the Gypsum Association
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PROCESSES RESEARCH, INC.
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B. EQUIPMENT COMPANIES
The Coe Manufacturing Co.
Painesville, Ohio 44077
The Ehrsam Co.
300 N. Cedar
Abilene, Kansas 67410
Combustion Engineering Co.
Raymond Division
427 W. Randolph St.
Chicago, Illinois 60606
C. STATES (Air Pollution Regulations)
California
California Air Resources Board
1108 14th Street
Sacramento, California 95814
Florida
Department of Pollution Control
Suite 300, Tallahassee Bank Building
315 South Calhoun St.
Tallahassee, Florida 32301
Georgia
Georgia Department of Public Health
47 Trinity Avenue S.W.
Atlanta, Georgia 30334
Indiana
Air Pollution Control Board
1330 Vest Michigan St.
Indianapolis, Indiana 46206
ATT: Mr. Perry E. Miller
Technical Secretary
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Iowa
Iowa Air Pollution Control Commission
Iowa State Department of Health
Lucas State Office Building
Des Moines, Iowa 50319
ATT: Mr. Charles Campbell
Michigan
Bureau of Industrial Health and Air Pollution Control
Department of Public Health
3500 N. Logan
Lansing, Michigan 48914
New Jersey
New Jersey State Department of Environmental Protection
Bureau of Air Pollution Control
P. 0. Box 1390
Trenton, New Jersey 08625
New York
New York State Department of Environmental Conservation
41 State Street
Albany, New York 12207
Oklahoma
Environmental Health Services
Air Pollution Control Division
Oklahoma State Department of Health
3400 N. Eastern
Oklahoma City, Oklahoma 73105
Oregon
Department of Environmental Quality
1400 Southwest Fifth Avenue
Portland, Oregon 97201
ATT: Mr. H. M. Patterson
Chief, Air Quality Control
Texas
Texas Air Control Board
1100 West 49th Street
Austin, Texas 78756
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D. PUBLICATIONS
1. American Petroleum Institute Engineering Reports
Cyclone Dust Collectors, 1955
Removal of Particulate Matter from Gaseous Wastes -
Filtration, 1961
Electrostatic Precipitators, 1961
2. Chemical Economics Handbook - Standford Research Institute,
July 1971
3. Chemical Engineering Deskbook
a_. Environmental Engineering, June 1971
b_. Environmental Engineering, May 1972
4. Combustion, August 1972
5. Environmental Science and Technology, October 1972
6. Mineral Industry Surveys - Gypsum (Quarterly)
U. S. Bureau of Mines, 1971
7. Minerals Yearbook - U. S. Bureau of Mines, 1970
8. Pit and Quarry, August 1961
9. Pit and Quarry Handbook, 1971-72
10. Rock Products, November 1960
11. Rock Products, June 1966
E. PLANT VISITS
National Gypsum Co.» Shoals, Indiana
United States Gypsum Co., Shoals, Indiana
Georgia-Pacific Corp., Buchanan, New York
United States Gypsum Co., Stony Point, New York
December 4, 1972
December 4, 1972
December 6, 1972
December 6, 1972
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