AP-42
Supplement 12
SUPPLEMENT NO. 12
FOR
COMPILATION
OF AIR POLLUTANT
EMISSION FACTORS,
THIRD EDITION
(INCLUDING SUPPLEMENTS 1-7)
U.S. Environmental Protection Agency
Region V, Library
230 South Dearborn Street
Chicago, Illinois 60604
U.S. ENVIRONMENTAL PROTECTION AGENCY
Office of Air, Noise and Radiation
"Office of Air Quality Planning and Standards
Research Triangle Park, North Carolina 27711
April 1981
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INSTRUCTIONS FOR INSERTING SUPPLEMENT 12
Into AP-42
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This document is issued by the Environmental Protection Agency
to report technical data of interest to a limited number of
readers. Copies are available free of charge to Federal
employees, current EPA contractors and grantees, and nonprofit
organizations - in limited quantities - from the Library
Services Office (MD 35), U. S. Environmental Protection Agency,
Research Triangle Park, North Carolina 27711; or, for a fee,
from the National Technical Information Service, 5285 Port
Royal Road, Springfield, Virginia 22161. This document is
also for sale to the public from the Superintendent of
Documents, U. S. Government Printing Office, Washington, DC.
Publication No. AP-42
ii
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CONTENTS
Page
INTRODUCTION
1. EXTERNAL COMBUSTION SOURCES 1-
.1 BITUMINOUS COAL COMBUSTION 1-
.2 ANTHRACITE COAL COMBUSTION 2-
.3 FUEL OIL COMBUSTION 3-
.4 NATURAL GAS COMBUSTION 4-
.5 LIQUIFIED PETROLEUM GAS COMBUSTION 5-
.6 WOOD WASTE COMBUSTION IN BOILERS 6-
.7 LIGNITE COMBUSTION 7-
.8 BAGASSE COMBUSTION IN SUGAR MILLS 8-
.9 RESIDENTIAL FIREPLACES 9-
.10 WOOD STOVES 1.10-
.11 WASTE OIL DISPOSAL 1.11-
2. SOLID WASTE DISPOSAL 2.0-
2.1 REFUSE INCINERATION 2.1-
2.2 AUTOMOBILE BODY INCINERATION 2.2-
2.3 CONICAL BURNERS 2.3-
2.4 OPEN BURNING 2.4-
2.5 SEWAGE SLUDGE INCINERATION 2.5-
3. INTERNAL COMBUSTION ENGINE SOURCES 3-
GLOSSARY OF TERMS 3-
3.1 HIGHWAY VEHICLES 3.1-
3.2 OFF-HIGHWAY MOBILE SOURCES 3.2-
3.3 OFF-HIGHWAY STATIONARY SOURCES 3.3-
4. EVAPORATION LOSS SOURCES 4.1-
4.1 DRY CLEANING 4.1-
4.2 SURFACE COATING 4.2-
4.3 STORAGE OF PETROLEUM LIQUIDS 4.3-
4.4 TRANSPORTATION AND MARKETING OF PETROLEUM LIQUIDS 4.4-
4.5 CUTBACK ASPHALT, EMULSIFIED ASPHALT AND ASPHALT CEMENT 4.5-
4.6 SOLVENT DECREASING 4.6-
4.7 WASTE SOLVENT RECLAMATION 4.7-
4.8 TANK AND DRUM CLEANING 4.8-
4.9 GRAPHIC ARTS 4.9-
4.10 CONSUMER/COMMERCIAL SOLVENT USE 4.10-
5. CHEMICAL PROCESS INDUSTRY 5.1-
5.1 ADIPIC ACID 5.1-
5.2 SYNTHETIC AMMONIA 5.2-
5.3 CARBON BLACK 5.3-
5.4 CHARCOAL 5.4-
5.5 CHLOR-ALKALI 5.5-
5.6 EXPLOSIVES 5.6-
5.7 HYDROCHLORIC ACID 5.7-
5.8 HYDROFLUORIC ACID 5.8-
5.9 NITRIC ACID 5.9-
5.10 PAINT AND VARNISH 5.10-
5.11 PHOSPHORIC ACID 5.11-
5.12 PHTHALIC ANHYDRIDE 5.12-
5.13 PLASTICS 5.13-
5.14 PRINTING INK 5.14-
5.15 SOAP AND DETERGENTS 5.15-
5.16 SODIUM CARBONATE 5.16-
5.17 SULFURIC ACID 5.17-
5.18 SULFUR RECOVERY 5.18-
5.19 SYNTHETIC FIBERS 5.19-
5.20 SYNTHETIC RUBBER 5.20-
5.21 TEREPHTHALIC ACID 521-
5.22 LEAD ALKYL 5.22-
5.23 PHARMACEUTICALS PRODUCTION 5.23-
5.24 MALEIC ANHYDRIDE 5.24-
111
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Page
6. FOOD AND AGRICULTURAL INDUSTRY 6.1-
6.1 ALFALFA DEHYDRATING 6.1-
6.2 COFFEE ROASTING 6.2-
6.3 COTTON GINNING 6.3-
6.4 FEED AND GRAIN MILLS AND ELEVATORS 6.4-
6.5 FERMENTATION 6.5-
6.6 FISH PROCESSING 6.6-
6.7 MEAT SMOKEHOUSES 6.7
6.8 AMMONIUM NITRATE FERTILIZERS 6.8-
6.9 ORCHARD HEATERS 6.9-
6.10 PHOSPHATE FERTILIZERS 6.10-
6.11 STARCH MANUFACTURING 6.11-
6.12 SUGAR CANE PROCESSING 6.12-
6.13 BREAD BAKING 6.13-
6.14 UREA 6.14-
6.15 BEEF CATTLE FEEDLOTS 6.15-
6.16 DEFOLIATION AND HARVESTING OF COTTON 6.16-
6.17 HARVESTING OF GRAIN 6.17-
6.18 AMMONIUM SULFATE 6.18-
7. METALLURGICAL INDUSTRY 7.1-
7.1 PRIMARY ALUMINUM PRODUCTION 7.1-
7.2 COKE PRODUCTION 7.2-
7.3 PRIMARY COPPER SMELTING 7.3-
7.4 FERROALLOY PRODUCTION 7.4-
7.5 IRON AND STEEL PRODUCTION 7.5-
7.6 PRIMARY LEAD SMELTING 7.6-
7.7 ZINC SMELTING 7.7-
7.8 SECONDARY ALUMINUM OPERATIONS 7.8-
7.9 SECONDARY COPPER SMELTING AND ALLOYING 7.9-
7.10 GRAY IRON FOUNDRIES 7.10-
7.11 SECONDARY LEAD SMELTING 7.11-
7.12 SECONDARY MAGNESIUM SMELTING 7.12-
7.13 STEEL FOUNDRIES 7.13-
7.14 SECONDARY ZINC PROCESSING 7.14-
7.15 STORAGE BATTERY PRODUCTION 7.15-
7.16 LEAD OXIDE AND PIGMENT PRODUCTION 7.16-
7.17 MISCELLANEOUS LEAD PRODUCTS 7.17-
7.18 LEADBEARING ORE CRUSHING AND GRINDING 7.18
8. MINERAL PRODUCTS INDUSTRY 8.1-
8.1 ASPHALTIC CONCRETE PLANTS 8.1-
8.2 ASPHALT ROOFING 8.2-
8.3 BRICKS AND RELATED CLAY PRODUCTS 8.3-
8.4 CALCIUM CARBIDE MANUFACTURING 8.4-
8.5 CASTABLE REFRACTORIES 8.5-
8.6 PORTLAND CEMENT MANUFACTURING 8.6-
8.7 CERAMIC CLAY MANUFACTURING 8.7-
8.8 CLAY AND FLY ASH SINTERING 8.8-
8.9 COAL CLEANING 8.9-
8.10 CONCRETE BATCHING 8.10-
8.11 GLASS FIBER MANUFACTURING 8.11-
8.12 FRIT MANUFACTURING 8.12-
8.13 GLASS MANUFACTURING 8.13-
8.14 GYPSUM MANUFACTURING 8.14-
8.15 LIME MANUFACTURING 8.15-
8.16 MINERAL WOOL MANUFACTURING 8.16-
8.17 PERL1TE MANUFACTURING 8.17-
8.18 PHOSPHATE ROCK PROCESSING 8.18-
8.19 SAND AND GRAVEL PROCESSING 8.19-
8.20 STONE QUARRYING AND PROCESSING 8.20-
8.21 COAL CONVERSION 8.21-
8.22 TACONITE ORE PROCESSING 8.22-
9. PETROLEUM INDUSTRY 9.1-
9.1 PETROLEUM REFINING 9.1-
9.2 NATURAL GAS PROCESSING 9.2-
IV
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Page
10. WOOD PRODUCTS INDUSTRY 10-1-
10.1 CHEMICAL WOOD PULPING 10.1-
10.2 PULPBOARD 10.2-
10.3 PLYWOOD VENEER AND LAYOUT OPERATIONS 10.3-
10.4 WOODWORKING WASTE COLLECTION OPERATIONS 10.4-
11. MISCELLANEOUS SOURCES 11.1-
11.1 FOREST WILDFIRES 11.1-
11.2 FUGITIVE DUST SOURCES 11.2-
11.3 EXPLOSIVES DETONATION 11.3-
APPENDIX A. MISCELLANEOUS DATA AND CONVERSION FACTORS A
APPENDIX B. EMISSION FACTORS AND NEW SOURCE PERFORMANCE STANDARDS
FOR STATIONARY SOURCES B-
APPENDIX C. NEDS SOURCE CLASSIFICATION CODES AND EMISSION
FACTOR LISTING C-
APPENDIX D. PROJECTED EMISSION FACTORS FOR HIGHWAY VEHICLES D-
APPENDIX E. TABLE OF LEAD EMISSION FACTORS E-
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PUBLICATIONS IN SERIES
Issuance
Compilation of Air Pollutant Emission Factors. Third Edition
(Including Supplements 1-7)
Supplement No. 8
Introduction
Section 1.10 Wood Stoves
Section 2.1 Refuse Incineration
Section 2.4 Open Burning
Section 3.0 Internal Combustion Engine Sources; Notice
Section 3.3 Off-Highway Stationary Souices
Section 6.3 Cotton Ginning
Section 6.8 Ammonium Nitrate Feitili/ers
Section 7.3 Primary Copper Smelting
Section 7.9 Secondaiy Copper Smelting and Alloying
Section 8.1 Asphaltic Concrete Plants
Section 8.2 Asphalt Roofing
Section 8.13 Glass Manufacturing
Section 9.1 Petroleum Refining
Section 11.2.1 Unpaved Roads (Dirt and Gravel)
Section 11.2.5 Paved Roads
Release Dale
8/77
12/77
Supplement No. 9
Section
Section
Section
Section
Section
Section
Section
Section
Section
Section
Section
Section
Section
Section
Section
Section
Section
Section
Section
Section
Section
Section 11.2.5
Appendix C
Appendix E
1.11
4.4
4.5
4.6
5.2
5.3
5.17
5.22
6.9
6.13
6.14
6.15
6.16
7.3
7.9
7.15
7.16
7.17
7.18
8.10
10.4
7/79
Bituminous Coal Combustion
Transportation and Marketing of Pel i oleum Liquids
Cutback Asphalt, Emulsified Asphalt and Asphalt Cements
Solvent Degreasing
Synthetic Ammonia
Carbon Black
Sulfunc Acid
Lead Alkyl
Orchard Heaters
Bread Baking
Urea
Beef Cattle Feedlots
Defoliation and Harvesting of Cotton
Primary Copper Smelting
Secondary Copper Smelting and Alloying
Storage Battery Production
Lead Oxide and Pigment Production
Miscellaneous Lead Products
Leadbearing Ore Crushing and Grinding
Concrete Batching
Woodworking Waste Collection Operations
Fugitive Dust - Paved Roads
NEDS Source Classification Codes and Emission Factor Listing
Table of Lead Emission Factors
vn
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PUBLICATIONS IN SERIES (CONT'D)
Issuance
Supplement No. 10
Section
Section
Section
Section
Section
Section
Section
Section
Section
Section
Section
Section
Section
Section
Section 10.3
Section 10.4
Section 11.3
Appendix A
3.2.1
4.7
4.8
5.8
5.11
5.18
6.5.2
6.17
7.6
8.9
8.11
8.18
8.21
8.?.?.
Release Date
2/80
Introduction
Internal Combustion Engine Sources - Aircraft
Waste Solvent Reclamation
Tank and Drum Cleaning
Hydrofluoric Acid
Phosphoric Acid
Sulfur Recovery
Fermentation - Wine Making
Harvesting of Grain
Primary Lead Smelting
Coal Cleaning
Glass Fiber Manufacturing
Phosphate Rock Processing
Coal Conversion
Taconite Ore Processing
Plywood Veneer and Layout Operations
Woodworking Waste Collection Operations
Explosives Detonation
Miscellaneous Data and Conversion Factors
Supplement No. 11
10/80
Section
Section
Section
Section
Section
Section
Section
Section
Section
Section
Section
5.9
5.23
5.24
6.10.1
6.10.2
6.10.3
7.2
7.3
7.5
7.11
9.1
Nitric Acid
Pharmaceuticals Production
Maleic Anhydride
Normal Superphosphates
Triple Superphosphates
Ammonium Phosphates
Coke Production
Primary Copper Smelting
Iron and Steel Production
Secondary Lead Smelting
Petroleum Refining
Supplement No. 12
4/81
Section 4.1 Dry Cleaning
Section 4.2 Surface Coating
Section 4.3 Storage of Organic Liquids
Section 4.6 Solvent Degreasing
Section 4.9 Graphic Arts
Section 4.10 Consumer/commercial Solvent Use
Section 5.17 Sulfuric Acid
Section 6.5.3 Beer Making
Section 6.18 Ammonium Sulfate
Section 7.1 Primary Aluminum
Section 7.8 Secondary Aluminum
Section 7.10 Gray Iron Foundries
Section 7.13 Steel Foundries
Section 7.14 Secondary Zinc
Section 8.1 Asphaltic Concrete
Section 8.2 Asphalt Roofing
Appendix C NEDS Source Classification Codes and Emission Factor Listing
Appendix E Table of Lead Emission Factors
Vlll
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4. EVAPORATION LOSS SOURCES
Evaporation losses include the organic solvents emitted from
dry cleaning plants and surface coating operations, and the volatile
matter in petroleum products. This chapter presents the volatile
organic emissions from these sources, including liquid petroleum
storage and marketing. Where possible, the effect is shown of
controls to reduce the emissions of organic compounds.
4.1 DRY CLEANING
4.1.1 General1'2
Dry cleaning involves the cleaning of fabrics with nonaqueous
organic solvents. The dry cleaning process requires three steps:
(1) washing the fabric in solvent, (2) spinning to extract excess
solvent and (3) drying by tumbling in a hot air stream.
Two general types of cleaning fluids are used in the industry,
petroleum solvents and synthetic solvents. Petroleum solvents,
such as Stoddard or 140-F, are inexpensive combustible hydrocarbon
mixtures similar to kerosene. Operations using petroleum solvents
are known as petroleum plants. Synthetic solvents are nonflammable
but more expensive halogenated hydrocarbons. Perchloroethylene and
trichlorotrifluoroethane are the two synthetic dry cleaning solvents
presently in use. Operations using these synthetic solvents are
respectively called "perc" plants and fluorocarbon plants.
There are two basic types of dry cleaning machines, transfer
and dry-to-dry. Transfer machines accomplish washing and drying in
separate machines. Usually, the washer extracts excess solvent
from the clothes before they are transferred to the dryer, but some
older petroleum plants have separate extractors for this purpose.
Dry-to-dry machines are single units that perform all of the washing,
extraction and drying operations. All petroleum solvent machines
are the transfer type, but synthetic solvent plants can be either
type.
The dry cleaning industry can be divided into three sectors,
coin operated facilities, commercial operations and industrial
cleaners. Coin operated facilities are usually part of a laundry
supplying "self-service" dry cleaning for consumers. Only synthetic
solvents are used in coin operated dry cleaning machines. Such
machines are small, with a capacity of 3.6 to 11.5 kg (8 to 25 Ib)
of clothing.
4/81 Evaporation Loss Sources 4.1-1
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EMISSION FACTORS
4/81
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Commercial operations, such as small neighborhood or franchise
dry cleaning shops, clean soiled apparel for the consumer. Generally,
perchloroethylene and petroleum solvents are used in commercial
operations. A typical "perc" plant operates a 14 to 27 kg (30 to
60 Ib) capacity washer/extractor and an equivalent size reclaiming
dryer.
Industrial cleaners are larger dry cleaning plants which
supply rental service of uniforms, mats, mops, etc., to businesses
or industries. Perchloroethylene is used by approximately 50 percent
of the industrial dry cleaning establishments. A typical large
industrial cleaner has a 230 kg (500 Ib) capacity washer/extractor
and three to six 38 kg (100 Ib) capacity dryers.
A typical perc plant is shown in Figure 4.1-1. Although one
solvent tank may be used, the typical perc plant uses two tanks for
washing. One tank contains pure solvent, and the other contains
"charged" solvent (used solvent to which small amounts of detergent
have been added to aid in cleaning). Generally, clothes are cleaned
in charged solvent and rinsed in pure solvent. A water bath may
also be used.
After the clothes have been washed, the used solvent is filtered,
and part of the filtered solvent is returned to the charged solvent
tank for washing the next load. The remaining solvent is then
distilled to remove oils, fats, greases, etc., and is returned to
the pure solvent tank. The resulting distillation bottoms are
typically stored on the premises until disposed of. The filter
cake and collected solids (muck) are usually removed from the
filter once a day. Before disposal, the muck may be "cooked" to
recover additional solvent. Still and muck cooker vapors are
vented to a condenser and separator, where more solvent is reclaimed.
In many perc plants, the condenser offgases are vented to a carbon
adsorption unit for additional solvent recovery.
After washing, the clothes are transferred to the dryer to be
tumbled in a heated air stream. Exhaust gases from the dryer,
along with a small amount of exhaust gases from the washer/extractor,
are vented to a water cooled condenser and water separator.
Recovered solvent is returned to the pure solvent storage tank. In
30 to 50 percent of the perc plants, the condenser offgases are
vented to a carbon adsorption unit for additional solvent recovery.
To reclaim this solvent, the unit must be periodically desorbed
with steam, usually at the end of each day. Desorbed solvent and
water are condensed and separated, and recovered solvent is returned
to the pure solvent tank.
A petroleum plant would differ from Figure 4.1-1 chiefly in
that there would be no recovery of solvent from the washer and
dryer and no muck cooker. A fluorocarbon plant would differ in
that an unvented refrigeration system would be used in place of a
carbon adsorption unit. Another difference is that a typical
4/81 Evaporation Loss Sources 4.1-3
-------
fluorocarbon plant could use a cartridge filter which is drained
and disposed of after several hundred cycles.
1-3
Emissions and Controls
The solvent itself is the primary emission from dry cleaning
operations. Solvent is given off by washer, dryer, solvent still,
muck cooker, still residue and filter muck storage areas, as well
as by leaky pipes, flanges and pumps.
Petroleum plants have not generally employed solvent recovery,
because of the low cost of petroleum solvents and the fire hazards
associated with collecting vapors. Some emission control, however,
can be obtained by maintaining all equipment (e.g., preventing lint
accumulation, solvent leakage, etc.) and by using good operating
practices (e.g., not overloading machinery). Both carbon adsorption
and incineration appear to be technically feasible controls for
petroleum plants, but costs are high.
Solvent recovery is necessary in perc plants due to the higher
cost of perchloroethylene. As shown in Figure 4.1-1, recovery is
effected on the washer, dryer, still and muck cooker through the
use of condensers, water/solvent separators and carbon adsorption
units. Typically once a day, solvent in the carbon adsorption unit
is desorbed with steam, condensed, separated from the condensed
water and returned to the pure solvent storage tank. Residual
solvent emitted from treated distillation bottoms and muck is not
recovered. As in petroleum plants, good emission control can be
obtained by good housekeeping (maintaining all equipment and using
good operating practices).
All fluorocarbon machines are of the dry-to-dry variety to
conserve solvent vapor, and all are closed systems with built in
solvent recovery. High emissions can occur, however, as a result
of poor maintenance and operation of equipment. Refrigeration
systems are installed on newer machines to recover solvent from the
washer/dryer exhaust gases.
Emission factors for dry cleaning operations are presented in
Table 4.1-1.
, Typical coin operated and commercial plants emit less than
10 grams (one ton) per year. Some applications of emission estimates
are too broad to identify every small facility. For estimates over
large areas, the factors in Table 4.1-2 may be applied for coin
operated and commercial dry cleaning emissions.
4.1-4 EMISSION FACTORS 4/81
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-------
TABLE 4.1-2. PER CAPITA SOLVENT LOSS EMISSION
FACTORS FOR DRY CLEANING PLANTS3
EMISSION FACTOR RATING: B
Emission Factors ,
Operation kg/yr/capita g/day/capita
(Ib/year/cap) (Ib/day/cap)
Commercial
Coin operated
0.6
(1.3)
0.2
(0.4)
1.9
(0.004)
0.6
(0.001)
Q
.References 2-4. All nonmethane VOC.
Assumes a 6 day operating week (313 days/yr).
References for Section 4.1
1. Study To Support New Source Performance Standards for the
Dry Cleaning Industry, EPA Contract No. 68-02-1412, TRW, Inc.,
Vienna, VA, May 1976.
2. Perchloroethylene Dry Cleaners - Background Information for
Proposed Standards. EPA-450/3-79-029a, U.S. Environmental
Protection Agency, Research Triangle Park, NC, August 1980.
3. Control of Volatile Organic Emissions from Perchloroethylene
Dry Cleaning Systems, EPA-450/2-78-050, U.S. Environmental
Protection Agency, Research Triangle Park, NC, December 1978.
4. Control of Volatile Organic Emissions from Petroleum Dry
Cleaners (Draft), Office of Air Quality Planning and Standards,
U.S. Environmental Protection Agency, Research Triangle Park,
NC, February 1981.
4.1-6 EMISSION FACTORS 4/81
-------
4.2 SURFACE COATING
Surface coating operations involve the application of paint,
varnish, lacquer or paint primer, for decorative or protective
purposes. This is accomplished by brushing, rolling, spraying,
flow coating and dipping operations. Some industrial surface
coating operations include automobile assembly, job enameling and
manufacturing of aircraft, containers, furniture, appliances and
plastic products. Nonindustrial applications of surface coatings
include automobile refinishing and architectural coating of domestic,
industrial, government and institutional structures, including
building interiors and exteriors and signs and highway markings.
Nonindustrial Surface Coating is discussed below in Section 4.2.1,
and Industrial Surface Coating in Section 4.2.2.
Emissions of volatile organic compounds (VOC) occur in surface
coating operations because of evaporation of the paint vehicles,
thinners and solvents used to facilitate the application of coatings.
The major factor affecting these emissions is the amount of volatile
matter contained in the coating. The volatile portion of most
common surface coatings averages about 50 percent, and most, if not
all, of this is emitted during the application and drying of the
coating. The compounds released include aliphatic and aromatic
hydrocarbons, alcohols, ketones, esters, alkyl and aryl hydrocarbon
solvents, and mineral spirits. Table 4.2-1 presents general emission
factors for surface coating operations.
TABLE 4.2-1. GENERAL EMISSION FACTORS FOR SURFACE
COATING APPLICATIONS3
EMISSION FACTOR RATING: B
Emissions
Coating Type kg/Mg Ib/ton
Paint5601120
Varnish and Shellac 500 1000
Lacquer 770 1540
Enamel 420 840
Primer (zinc chromate) 660 1320
a
.Reference 1.
Nonmethane VOC. Reference 4.
4/81 Evaporation Loss Sources 4.2-1
-------
-------
4.2.1 NONINDUSTRIAL SURFACE COATING1'3'5
Nonindustrial surface coating operations are nonmanufacturing
applications of surface coating. Two major categories are architectural
surface coating and automobile refinishing. Architectural uses are
considered to include both industrial and nonindustrial structures.
Automobile refinishing pertains to the painting of damaged or worn
highway vehicle finishes and not the painting of vehicles during
manufacture.
Emissions from a single architectural structure or automobile
refinishing are calculated by using total volume and content and
weight of volatile constituents for the coating employed in the
specific application. Estimating emissions for a large area which
includes many major and minor applications of nonindustrial surface
coatings requires that area source estimates be developed. Archi-
tectural surface coating and auto refinishing emissions data are
often difficult to compile for a large geographical area. In cases
where a large inventory is being developed and/or resources are
unavailable for detailed accounting of actual volume of coatings
for these applications, emissions may be assumed proportional to
population or number of employees. Table 4.2.1-1 presents factors
from national emission data and emissions per population or employee
for architectural surface coating and automobile refinishing.
TABLE 4.2.1-1. NATIONAL EMISSIONS AND EMISSION FACTORS
FOR VOC FROM ARCHITECTURAL SURFACE COATING
AND AUTOMOBILE REFINISHING3
EMISSION FACTOR RATING: C
Emissions
National
Mg/yr
ton/yr
Architectural Surface
Coating
446,000
491,000
Automobile
Refinishing
181,000
199,000
Per capita
kg/yr (Ib/yr) 21.4 (4.6) , 0.84 (1.9)
g/day (Ib/day) 5.8 (0.013) 2.7 (0.006)
Per employee
Mg/yr (ton/yr) - 2.3 (2.6)
kg/day (Ib/day) - 7.4 (16.3)
o
.References 3 and 5-8. All nonmethane organics.
Reference 8. Calculated by dividing kg/yr (Ib/yr) by 365 days and
converting to appropriate units. Assumes that 75% of annual
emissions occurs over a 9 month ozone season. For shorter ozone
seasons, adjust accordingly.
Assumes a 6 day operating week (313 days/yr).
4/81 Evaporation Loss Sources 4.2.1-1
-------
The use of waterborne architectural coatings reduces volatile
organic compound emissions. Current consumption trends indicate
increasing substitution of waterborne architectural coatings for
those using solvent. Automobile refinishing often is done in areas
only slightly enclosed, which makes control of emissions difficult.
Where automobile refinishing takes place in an enclosed area,
control of the gaseous emissions can be accomplished by the use of
adsorbers (activated carbon) or afterburners. The collection
efficiency of activated carbon has been reported at 90 percent or
greater. Water curtains or filler pads have little or no effect on
escaping solvent vapors, but they are widely used to stop paint
particulate emissions.
References for Section 4.2.1
1. Air Pollution Engineering Manual, Second Edition, AP-40, U.S.
Environmental Protection Agency, Research Triangle Park, NC,
May 1973. Out of Print.
2. Control Techniques for Hydrocarbon and Organic Gases from
Stationary Sources, AP-68, U.S. Environmental Protection
Agency, Research Triangle Park, NC, October 1969.
3. Control Techniques Guideline for Architectural Surface Coatings
(Draft), Office of Air Quality Planning and Standards, U.S.
Environmental Protection Agency, Research Triangle Park, NC,
February 1979.
4. Air Pollutant Emission Factors, Contract No. CPA-22-69-119,
Resources Research Inc., Reston, VA, April 1970.
5. Procedures for the Preparation of Emission Inventories for
Volatile Organic Compounds, Volume I, Second Edition,
EPA-450/2-77-028, U.S. Environmental Protection Agency, Research
Triangle Park, NC, September 1980.
6. W.H. Lamason, "Technical Discussion of Per Capita Emission
Factors for Several Area Sources of Volatile Organic Compounds",
Monitoring and Data Analysis Division, U.S. Environmental
Protection Agency, Research Triangle Park, NC, March 15, 1981.
Unpublished.
7. End Use of Solvents Containing Volatile Organic Compounds,
EPA-450/3-79-032, U.S. Environmental Protection Agency, Research
Triangle Park, NC, May 1979.
8. Written communications between Bill Lamason and Chuck Mann,
Monitoring and Data Analysis Division, U.S. Environmental
Protection Agency, Research Triangle Park, NC, October 1980
and March 1981.
4.2.1-2 EMISSION FACTORS 4/81
-------
9. Final Emission Inventory Requirements for 1982 Ozone State
Implementation Plans, EPA-450/4-80-016, U.S. Environmental
Protection Agency, Research Triangle Park, NC, December 1980,
4/81 Evaporation Loss Sources 4.2.1-3
-------
-------
4.2.2. INDUSTRIAL SURFACE COATING
4.2.2.1 General1"4
Process Description - Surface coating is the application of decorative
or protective materials in liquid or powder form to substrates.
These coatings normally include general solvent type paints, varnishes,
lacquers and water thinned paints. After application of coating by
one of a variety of methods such as brushing, rolling, spraying,
dipping and flow coating, the surface is air and/or heat dried to
remove the volatile solvents from the coated surface. Powder type
coatings can be applied to a hot surface or be melted after application
and caused to flow together. Other coatings can be polymerized
after application by thermal curing with infrared or electron beam
systems.
Coating Operations - There are both "toll" ("independent") and
"captive" surface coating operations. Toll operations fill orders
to various manufacturer specifications, and thus change coating and
solvent conditions more frequently than do captive companies, which
fabricate and coat products within a single facility and which may
operate continuously with the same solvents. Toll and captive
operations differ in emission control systems applicable to coating
lines, because not all controls are technically feasible in toll
situations.
Coating Formulations - Conventional coatings contain at least
30 volume percent solvents to permit easy handling and application.
They typically contain 70 to 85 percent solvents by volume. These
solvents may be of one component or of a mixture of volatile ethers,
acetates, aromatics, cellosolves, aliphatic hydrocarbons and/or
water. Coatings with 30 volume percent of solvent or less are
called low solvent or "high solids" coatings.
Waterborne coatings, which have recently gained substantial
use, are of several types: water emulsion, water soluble and
colloidal dispersion, and electrocoat. Common ratios of water to
solvent organics in emulsion and dispersion coatings are 80/20 and
70/30.
Two part catalyzed coatings to be dried, powder coatings, hot
melts, and radiation cured (ultraviolet and electron beam) coatings
contain essentially no volatile organic compounds (VOC), although
some monomers and other lower molecular weight organics may volatilize.
Depending on the product requirements and the material being
coated, a surface may have one or more layers of coating applied.
The first coat may be applied to smooth surface imperfections or to
assure adhesion of the coating. The intermediate coats usually
provide the required color, texture or print, and a clear protective
topcoat is often added. General coating types do not differ from
4/81 Evaporation Loss Sources 4.2.2-1
-------
those described, although the intended use and the material to be
coated determine the composition and resins used in the coatings.
Coating Application Procedures - Conventional spray, which is
air atomized and usually hand operated, is one of the most versatile
coating methods. Colors can be changed easily, and a variety of
sizes and shapes can be painted under many operating conditions.
Conventional, catalyzed or waterborne coatings can be applied with
little modification. The disadvantages are low efficiency from
overspray and high energy requirements for the air compressor.
In hot airless spray, the paint is forced through an atomizing
nozzle. Since volumetric flow is less, overspray is reduced. Less
solvent is also required, thus reducing VOC emissions. Care must
be taken for proper flow of the coating to avoid plugging and
abrading of the nozzle orifice. Electrostatic spray is most efficient
for low viscosity paints. Charged paint particles are attracted to
an oppositely charged surface. Spray guns, spinning discs or bell
shaped atomizers can be used to atomize the paint. Application
efficiencies of 90 to 95 percent are possible, with good wraparound
and edge coating. Interiors and recessed surfaces are difficult to
coat, however.
Roller coating is used to apply coatings and inks to flat
surfaces. If the cylindrical rollers move in the same direction as
the surface to be coated, the system is called a direct roll coater.
If they rotate in the opposite direction, the system is a reverse
roll coater. Coatings can be applied to any flat surface efficiently
and uniformly and at high speeds. Printing and decorative graining
are applied with direct rollers. Reverse rollers are used to apply
fillers to porous or imperfect substrates, including papers and
fabrics, to give a smooth uniform surface.
Knife coating is relatively inexpensive, but is not appropriate
for coating unstable materials, such as some knitgoods, or when a
high degree of accuracy in the coating thickness is required.
Rotogravure printing is widely used in coating vinyl imitation
leathers and wallpaper, and in the application of a transparent
protective layer over the printed pattern. In rotogravure printing,
the image area is recessed, or "intaglio", relative to the copper
plated cylinder on which the image is engraved. The ink is picked
up on the engraved area, and excess ink is scraped off the nonimage
area with a "doctor blade". The image is transferred directly to
the paper or other substrate, which is web fed, and the product is
then dried.
Dip coating requires that the surface of the subject be immersed
in a bath of paint. Dipping is effective for coating irregularly
shaped or bulky items and for priming. All surfaces are covered,
but coating thickness varies, edge blistering can occur and a good
appearance is not always achieved.
It.2.2-2 EMISSION FACTORS 4/81
-------
In flow coating, materials to be coated are conveyed through a
flow of paint. Paint flow is directed, without atoraization, towards
the surface through multiple nozzles, then is caught in a trough
and recycled. For flat surfaces, close control of film thickness
can be maintained by passing the surface through a constantly
flowing curtain of paint at a controlled rate.
Emissions and Controls - Essentially all of the VOC emitted
from the surface coating industry is from the solvents which are
used in the paint formulations, used to thin paints at the coating
facility or used for cleanup. All unrecovered solvent can be
considered as potential emissions. Monomers and low molecular
weight organics can be emitted from those coatings that do not
include solvents, but these emissions are essentially negligible.
Emissions from surface coating for an uncontrolled facility
can be estimated by assuming that all VOC in the coatings is emitted.
Usually, coating consumption volume will be known, and some information
about the types of coatings and solvents will be available. The
choice of a particular emission factor will depend on the coating
data available. If no specific information is given for the coating,
it may be estimated from the data in Table 4.2.2.1-2.
TABLE 4.2.2.1-1. VOC EMISSION FACTORS FOR UNCONTROLLED
SURFACE COATING3
EMISSION FACTOR RATING: B
Emissions of VOC
Available Information on Coating kg/liter of coating Ib/gal of coating
Conventional or waterborne paints
VOC, wt 7. (d) d-coating density d'coating density
100 100
VOC, vol % (V) V-0.88d V-7.36d
100 100
Waterborne paint
VOC as weight \ of total
volatiles - including water (X); d-K-coating density d-X'Coating density
total volatiles as weight % 100 100
of coating (d)
VOC as volume % of total ,
volatiles - including water (Y); V-Y-0.88 V-Y-7.36
total volatiles as volume % 100 100
of coating (V)
^Material balance, when coatings volume use is known.
For special purposes, factors expressed as kg/liter of coating less water may
be desired. These may be computed as follows:
Factor as kc/liter of coating , ,., ,
L . vo?ume % water & - Factor as kg/liter of coating less water
100
If the coating den;
-t T U 1 *. I. "i 1 1 1
If the coating density is not known, it can be estimated from the information
in Table 4.2.2.1-2.
The values 0.88 (kg/liter) and 7.36 (Ib/gal) use the average density oE solvent
in coatings. Use the densities of the solvents in the coatings actually used
by the source, if known.
4/81 Evaporation Loss Sources 4.2.2-3
-------
TABLE 4.2.2.1-2. TYPICAL DENSITIES AND SOLIDS CONTENTS OF COATINGS
Type of Coating Density Solids
kg/liter Ib/gal (% by volume)
Enamel, air dry
Enamel, baking
Acrylic enamel
Alkyd enamel
Primer surfacer
Primer, epoxy
Varnish , baking
Lacquer, spraying
Vinyl, roller coat
Polyurethane
Stain
Sealer
Magnet wire enamel
Paper coating
Fabric coating
0.91
1.09
1.07
0.96
1.13
1.26
0.79
0.95
0.92
1.10
0.88
0.84
0.94
0.92
0.92
7.6
9.1
8.9
8.0
9.4
10.5
6.6
7.9
7.7
9.2
7.3
7.0
7.8
7.7
7.7
39.6
42.8
30.3
47.2
49.0
57.2
35.3
26.1
12.0
31.7
21.6
11.7
25.0
22.0
22.0
Reference 4.
All solvents separately purchased as solvent that are used in
surface coating operations and not recovered subsequently can be
considered potential emissions. Such VOC emissions at a facility
can result from onsite dilution of coatings with solvent, from
"makeup solvents" required in flow coating and, in some instances,
dip coating, and from the solvents used for cleanup. Makeup solvents
are added to coatings to compensate for standing losses, concentration
or amount, and thus to bring the coating back to working specifi-
cations. Solvent emissions should be added to VOC emissions from
coatings to get total emissions from a coating facility.
TABLE 4.2.2.1-3. CONTROL EFFICIENCIES FOR
SURFACE COATING OPERATIONS3
Control Option Reduction
Substitute waterborne coatings 60-95
Substitute low solvent coatings 40-80
Substitute powder coatings 92-98
Add afterburners/ incinerators 95
3.
.References 1-3.
Expressed as % of total uncontrolled emission load.
4.2.2-4 EMISSION FACTORS 4/81
-------
Typical ranges of control efficiencies are given in
Table 4.2.2.1-3. Emission controls normally fall under one of
three categories - modifications in paint formula, process changes,
or addon controls. These are discussed further in the specific
subsections which follow.
r Q
4.2.2.2 Coil and Can Coating
Process Description - Coil coating is the coating of any flat metal
sheet or strip that comes in rolls or coils. Cans are made from
two or three flat pieces of metal, so can coating is included
within this broad category, as are the coating of screens, fencing,
metal doors, aluminum siding and a variety of other products.
Figure 4.2.2.2-1 shows a typical coil coating line, and
Figure 4.2.2.2-2 depicts a three piece can sheet printing operation.
There are both "toll" and "captive" coil coating operations.
The former fill orders to customer specifications, and the latter
coat the metal for products fabricated within one facility. Some
coil coating operations do both toll and captive work.
Coil coating lines have one or more coaters, each followed by
an oven (see Figure 4.2.2.2-1). The metal is cleaned and treated
for corrosion protection and proper coating adhesion (see Section 4.6,
Solvent Degreasing). The prime coat is applied, on one or both
sides, by three or more powered rollers. This coating is dried or
baked, then is cooled in a quench chamber, either by a spray of
water or by a blast of air followed by water. It is usually reverse
roller coated. A prime or single coat may also be applied by
electrodeposition, when a waterborne coating is used.
Oven temperatures range from 40 to 380°C (100 to 1000°F),
depending on the type and desired thickness of the coating and on
the type of metal being coated. A topcoat may be applied and cured
in a similar manner.
In can coating, as with coil coating, there are both toll and
captive manufacturers. Some plants coat metal sheets, some make
three piece cans, some fabricate and coat two piece cans, and some
fabricate can ends. Others perform combinations of these processes.
Cans may be made from a rectangular sheet (body blank) and two
circular ends ("three piece" cans) or they can be drawn and wall
ironed from a shallow cup to which an end is attached after the can
is filled ("two piece" cans). There are major differences in
coating practices, depending on the type of can and the product
packaged in it.
Three piece can manufacturing involves sheet coating and can
fabricating. Sheet coating includes base coating and printing or
lithographing, followed by curing at tmeperatures of up to 220°C
4/81 Evaporation Loss Sources 4.2.2-5
-------
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HUSSION FACTORS
4/81
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(425°F). When the sheets have been formed into cylinders, the seam
is sprayed, usually with a lacquer, to protect the exposed metal.
If they are to contain an edible product, the interiors are spray
coated, and the cans baked at up to 220°C (425°F). See
Figure 4.2.2.2-2.
Two piece cans are largely used by beer and other beverage
industries. The exteriors may be reverse roll coated in white and
cured at 170 to 200°C (325 to 400°F). Several colors of ink are
then transferred (sometimes by lithographic printing) to the cans
as they rotate on a mandrel. A protective varnish may be roll
coated over the inks. The coating is then cured in a single or
multipass oven at temperatures of 180 to 200°C (350 to 400°F). The
cans are spray coated on the interior and spray and/or roll coated
on the exterior of the bottom end. A final baking at 110 to 200°C
(225 to 400°F) completes the process.
Emissions and Controls - Emissions from coil and can coating operations
depend on composition of the coating, coated area, thickness of
coat and efficiency of application. Post-application chemical
changes, and nonsolvent contaminants like oven fuel combustion pro-
ducts, may also affect the composition of emissions. All solvent
used and not recovered can be considered potential emissions.
Coil coating emissions come from the coating area, the oven
and the quench area. They consist of volatile organics and other
compounds, such as aldehydes, from the thermal degradation of
volatile organics. Emissions from combustion of natural gas,
generally used to heat the ovens, are discussed in Section 1.4.
Emissions from coil coating can be estimated from the amount of
coating applied by using the factors in Table 4.2.2.1-1.
Incineration and the use of waterborne and low solvent coatings
both reduce organic vapor emissions. Other technically feasible
control options, such as electrostatically sprayed powder coatings,
are not presently applicable to the whole industry. Catalytic and
thermal incinerators both can be used, preferably with primary
and/or secondary heat recovery systems. Waterborne primers, backers
(coatings on the reverse or backside of the coil), and some waterborne
low to medium gloss topcoats have been developed that equal the
performance of organic solventborne coatings for aluminum but have
not yet been applied at full line speed in all cases. Waterborne
coatings for other metals are being developed.
Sources of can coating VOC emissions include the coating area
and the oven area of the sheet base and lithographic coating lines,
the three piece can side seam and interior spray coating processes,
and the two piece can coating and end sealing compound lines.
Emission rates vary with line speed, can or sheet size and coating
type. On sheet coating lines, where the coating is applied by
4.2.2-8 EMISSION FACTORS 4/81
-------
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Evaporation Loss Sources
4.2.2.-9
-------
rollers, most solvent evaporates in the oven. For other coating
processes, the coating operation itself is the major source. Emis-
sions can be estimated from the amount of coating applied by using
the factors in Table 4.2.2.1-1 or, if the number and general nature
of the coating lines is known, from Table 4.2.2.2-1.
Available control technology includes the use of addon devices
like incinerators and carbon adsorbers and the conversion to low
solvent and ultraviolet curable coatings. Thermal and catalytic
incinerators both may be used to control emissions from three piece
can sheet base coating lines, sheet lithographic coating lines, and
interior spray coating. Incineration is applicable to two piece can
coating lines. Carbon adsorption is most acceptable to low tempera-
ture processes which use a limited number of solvents. Such processes
include two and three piece can interior spray coating, two piece
can end sealing compound lines, and three piece can side seam spray
coating.
Low solvent coatings are not yet available to replace all the
organic solventborne formulations presently used in the can industry.
Waterborne basecoats have been successfully applied to two piece
cans. Powder coating technology is used for side seam coating of
noncemented three piece cans.
Ultraviolet curing technology is available for rapid drying
of the first two colors of ink on three piece can sheet lithographic
coating lines.
Table 4.2.2.2-2 shows control efficiencies for typical coil
and can coating lines.
9
4.2.2.3 Magnet Wire Coating
Process Description - Magnet wire coating is applying a coat of
electrically insulating varnish or enamel to aluminum or copper
wire used in electrical machinery. The wire is usually coated in
large plants that both draw and insulate it and then sell it to
electrical equipment manufacturers. The wire coating must meet
rigid electrical, thermal and abrasion specifications.
Figure 4.2.2.3-1 shows a typical wire coating operation. The
wire is unwound from spools and passed through an annealing furnace.
Annealing softens the wire and cleans it by burning off oil and
dirt. Usually, the wire then passes through a bath in the coating
applicator and is drawn through an orifice or coating dia to scrape
off the excess. It is then dried and cured in a two zone oven at
200°, then 430°C (400 and 806°F). Wire may pass through the coating
applicator and the oven as many as twelve times to acquire the
necessary thickness of coating.
4.2.2-10 EMISSION FACTORS 4/81
-------
TABLE 4.2.2.2-2. CONTROL EFFICIENCIES FOR COIL
AND CAN COATING LINES3
Affected Facility"
Control Option
Reduction
Coil Coating Lines
Two Piece Can Lines
Exterior coating
Interior spray
coating
Three Piece Can Lines
Sheet coating lines
Exterior coating
Interior spray
coating
Can fabricating lines
Side seam spray
coating
Interior spray
coating
Thermal incineration 90-98
Catalytic incineration 90
Waterborne and high
solids coating 70-95
Thermal and catalytic
incineration 90
Waterborne and high
solids coating 60-90
Ultraviolet curing up to 100
Thermal and catalytic
incineration 90
Waterborne and high
solids coating 60-90
Powder coating 100
Carbon adsorption 90
Thermal and catalytic
incineration 90
Waterborne and high
solids coating 60-90
Ultraviolet curing up to 100
Thermal and catalytic
incineration 90
Uaterborne and high
solids coating 60-90
Waterborne and high
solids coating 60-90
Powder (only for un-
cemented seams) 100
Thermal and catalytic
incineration 90
Waterborne and high
solids coating 60-90
Powder (only for un-
cemented seams) 100
Carbon adsorption 90
End Coating Lines
Sealing compound
Sheet coating
Waterborne and high
solids coating 70-95
Carbon adsorption 90
Thermal and catalytic
incineration 90
Waterborne and high
solids coating 60-90
^Reference 7.
Coil coating lines consist of coaters, ovens and quench areas.
Sheet, can and end wire coating lines consist of coaters and
covens.
Compared to conventional solvent base coatings used without any
added controls.
4/81
Evaporation Loss Sources
4.2.2-11
-------
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4.2.2-12
EMISSION FACTORS
4/81
-------
Emissions and Controls - Emissions from wire coating operations
depend on composition of the coating, thickness of coat and effi-
ciency of application. Postapplication chemical changes, and
nonsolvent contaminants such as oven fuel combustion products, may
also affect the composition of emissions. All solvent used and not
recovered can be considered potential emissions.
The exhaust from the oven is the most important source of
solvent emissions in the wire coating plant. Emissions from the
applicator are comparatively low because a dip coating technique is
used. See Figure 4.2.2.3-1.
VOC emissions may be estimated from the factors in
Table 4.2.2.1-1, if the coating usage is known and if the coater
has no controls. Most wire coaters built since 1960 do have con-
trols, so the information in the following paragraph may be applicable.
Table 4.2.2.3-1 gives estimated emissions for a typical wire coating
line.
Incineration is the only commonly used technique to control
emissions from wire coating operations. Since about 1960, all
major wire coating designers have incorporated catalytic incinerators
into their oven designs, because of the economic benefits. The
internal catalytic incinerator burns solvent fumes and circulates
heat back into the wire drying zone. Fuel otherwise needed to
operate the oven is eliminated or greatly reduced, as are costs.
Essentially all solvent emissions from the oven can be directed to
an incinerator with a combustion efficiency of at least 90 percent.
TABLE 4.2.2.3-1. ORGANIC SOLVENT EMISSIONS FROM A
TYPICAL WIRE COATING LINEa
Coating Line Annual Totals
kg/hr
12
Ib/hr
26
Mg/yr
84
ton/yr
93
o
.Reference 9.
Organic solvent emissions vary from line to line by
size and speed of wire, number of wires per oven, and
number of passes through the oven. A typical line may
coat 1,200 pounds of wire per day. A plant may have
many lines.
Based upon normal operating conditions of 7,000 hr/yr
for one line without incinerator.
Ultraviolet cured coatings are available for special systems.
Carbon adsorption is not practical. Use of low solvent coatings is
only a potential control, because they have not yet been developed
with properties that meet industry's requirements.
4/81 Evaporation Loss Sources 4.2.2-13
-------
4.2.2.4 Other Metal Coating11"13
Process Description - Large appliance, metal furniture and
miscellaneous metal parts and products coating lines have many
common operations, similar emissions and emission points, and
available control technology. Figure 4.2.2.4-1 shows a typical
metal furniture coating line.
Large appliances include doors, cases, lids, panels and interior
support parts of washers, dryers, ranges, refrigerators, freezers,
water heaters, air conditioners and associated products. Metal
furniture includes both outdoor and indoor pieces manufactured for
household, business or institutional use. "Miscellaneous parts and
products" herein denotes large and small farm machinery, small
appliances, commercial and industrial machinery, fabricated metal
products and other industries that coat metal under Standard Industrial
Classification (SIC) codes 33 through 39.
Large Appliances - The coatings applied to large appliances
are usually epoxy, epoxy/acrylic or polyester enamels for the
primer or single coat, and acrylic enamels for the topcoat. Coatings
containing alkyd resins are also used. Prime and interior single
coats are applied at 25 to 36 volume percent solids. Topcoats and
exterior single coats are applied at 30 to 40 volume percent.
Lacquers may be used to touch up any scratches that occur during
assembly. Coatings contain 2 to 15 solvents, typical of which are
esters, ketones, aliphatics, alcohols, aromatics, ethers and terpenes.
Small parts are generally dip coated, and flow or spray coating
is used for larger parts. Dip and flow coating are performed in an
enclosed room vented either by a roof fan or by an exhaust system
adjoining the drain board or tunnel. Down or side draft booths
remove overspray and organic vapors from prime coat spraying.
Spray booths are also equipped with dry filters or a water wash to
trap overspray.
Parts may be touched up manually with conventional or airless
spray equipment. Then they are sent to a flashoff area (either
open or tunneled) for about 7 minutes and are baked in a multipass
oven for about 20 minutes at 180 to 230°C (350 to 450°F). At that
point, large appliance exterior parts go on to the topcoat applica-
tion area, and single coated interior parts are moved to the assembly
area of the plant.
The topcoat, and sometimes primers, are applied by automated
electrostatic disc, bell or other types of spray equipment. Topcoats
often are more than one color, changed by automatically flushing
out the system with solvent. Both the topcoat and touchup spray
areas are designed with side or down draft exhaust control.
The parts go through about a 10 minute flashoff period, followed
by baking in a multipass oven for 20 to 30 minutes at 140 to 180°C
(270 to 350°F).
4.2.2-14 EMISSION FACTORS 4/81
-------
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Metal Furniture - Most metal furniture coatings are enamels,
although some lacquers are used. The most common coatings are alkyds,
epoxies and acrylics, which contain the same solvents used in large
appliance coatings, applied at about 25 to 35 percent solids.
On a typical metal furniture coating line (see Figure 4.2.2.4-1),
the prime coat can be applied with the same methods used for large
appliances, but it may be cured at slightly lower temperatures,
150 to 200°C (300 to 400°F). The topcoat, usually the only coat,
is applied with electrostatic spray or with conventional airless or
air spray. Most spray coating is manual, in contrast to large
appliance operations. Flow coating or dip coating is done, if the
plant generally uses only one or two colors on a line.
The coated furniture is usually baked, but in some cases it is
air dried. If it is to be baked, it passes through a flashoff area
into a multizone oven at temperatures ranging from 150 to 230°C
(300 to 450°F).
Miscellaneous Metal Parts and Products - Both enamels (30 to
40 volume percent solids) and lacquers (10 to 20 volume percent
solids) are used to coat miscellaneous metal parts and products,
although enamels are more common. Coatings often are purchased at
higher volume percent solids but thinned prior to application (fre-
quently with aromatic solvent blends). Alkyds are popular with
industrial and farm machinery manufacturers. Most of the coatings
contain several (up to 10) different solvents, including ketones,
esters, alcohols, aliphatics, ethers, aromatics and terpenes.
Coatings are applied in conveyorized or batch, single or two
coat, operations. Spraying is usually employed for single coats.
Flow and dip coating may be used when only one or two colors are
applied. For two coat operations, primers are usually applied by
flow or dip coating, and topcoats are almost always applied by
spraying. Electrostatic spraying is common. Spray booths or areas
are kept at a slight negative pressure to capture overspray.
A manual two coat operation may be used for large items like
industrial and farm machinery. The coatings on large products are
often air dried rather than oven baked, because the machinery, when
completely assembled, includes heat sensitive materials and may be
too large to be cured in an oven. Miscellaneous parts and products
can be baked in single or multipass ovens at 150 to 230°C (300 to
450°F).
Emissions and Controls - Volatile organic compounds are emitted
from application and flashoff areas and the ovens of metal coating
lines. See Figure 4.2.2.4-1. The composition of emissions varies
among coating lines according to physical construction, coating
method and type of coating applied, but distribution of emissions
among individual operations has been assumed to be fairly constant,
4.2.2-16 EMISSION FACTORS 4/81
-------
regardless of the type of coating line or the specific product
coated, as Table 4.2.2.4-2 indicates. All solvent used can be
considered potential emissions. Emissions can be calculated from
the factors in Table 4.2.2.1-1 if coatings use is known, or from
the factors in Table 4.2.2.4-2 if only a general description of the
plant is available. For emissions from the cleansing and pretreatment
area, see Section 4.6, Solvent Degreasing.
When powder coatings, which contain almost no VOC, are applied
to some metal products as a coating modification, emissions are
greatly reduced. Powder coatings are applied as single coats on
some large appliance interior parts and as topcoat for kitchen
ranges. They are also used on metal bed and chair frames, shelving
and stadium seating, and they have been applied as single coats on
small appliances, small farm machinery, fabricated metal product
parts and industrial machinery components. The usual application
method is manual or automatic electrostatic spray.
Improving transfer efficiency is a method of reducing emissions.
One such technique is the electrostatic application of the coating,
and another is dip coating with waterborne paint. For example,
many makers of large appliances are now using electrodeposition to
apply prime coats to exterior parts and single coats to interiors,
because this technique increases corrosion protection and resistance
to detergents. Electrodeposition of these waterborne coatings is
also being used at several metal furniture coating plants and at
some farm, commercial machinery and fabricated metal products
facilities.
Automated electrostatic spraying is most efficient, but manual
and conventional methods can be used, also. Roll coating is another
option on some miscellaneous parts. Use of higher solids coatings
is a practiced technique for reduction of VOC emissions.
Carbon adsorption is technically feasible for collecting
emissions from prime, top and single coat applications and flashoff
areas. However, the entrained sticky paint particles are a
filtration problem, and adsorbers are not commonly used.
Incineration is used to reduce organic vapor emissions from
baking ovens for large appliances, metal furniture and miscellaneous
products, and it is an option for control of emissions from
application and flashoff areas.
Table 4.2.2.4-1 gives estimated control efficiencies for large
appliance, metal furniture and miscellaneous metal part and product
coating lines, and Table 4.2.2.4-2 gives their emission factors.
4.2.2.5 Flat Wood Interior Panel Coating
14
Process Description - Prefinished flat wood construction products
are interior panels made of hardwood plywoods (natural and lauan),
particle board, and hardboard.
4/81 Evaporation Loss Sources 4.2.2.-17
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Fewer than 25 percent of the manufacturers of such flat wood
products coat the products in their plants, and in some of the plants
that do coat, only a small percentage of total production is coated.
At present, most coating is done by toll coaters who receive panels
from manufacturers and undercoat or finish them according to customer
specifications and product requirements.
Some of the layers and coatings that can be factory applied to
flat woods are filler, sealer, groove coat, primer, stain, basecoat,
ink and topcoat. Solvents used in organic base flat wood coatings
are usually component mixtures, including methyl ethyl ketone, methyl
isobutyl ketone, toluene, xylene, butyl acetates, propanol, ethanol,
butanol, naphtha, methanol, amyl acetate, mineral spirits, SoCal I
and II, glycols, and glycol ethers. Those most often used in water-
borne coatings are glycol, glycol ethers, propanol and butanol.
Various forms of roll coating are the preferred techniques for
applying coatings to flat woods. Coatings used for surface cover
can be applied with a direct roller coater, and reverse roll coaters
are generally used to apply fillers, forcing the filler into panel
cracks and voids. Precision coating and printing (usually with
offset gravure grain printers) are also forms of roll coating, and
several types of curtain coating may be employed, also (usually for
topcoat application). Various spray techniques and brush coating
may be used, too.
Printed interior panelings are produced from plywoods with
hardwood surfaces (primarily lauan) and from various wood composition
panels, including hardboard and particle board. Finishing
techniques are used to cover the original surface and to produce
various decorative effects. Figure 4.2.2.5-1 is a flow diagram
showing some, but not all, typical production line variations for
printed interior paneling.
Groove coatings, applied in different ways and at different
points in the coating procedure, are usually pigmented low resin
solids reduced with water prior to use, therefore yielding few, if
any, emissions. Fillers, usually applied by reverse roll coating,
may be of various formulations: (1) polyester (which is ultraviolet
cured), (2) water base, (3) lacquer base, (4) polyurethane and
(5) alkyd urea base. Water base fillers are in common use on
printed paneling lines.
Sealers may be of water or solvent base, usually applied by
airless spray or direct roll coating, respectively. Basecoats,
which are usually direct roll coated, generally are of lacquer,
synthetic, vinyl, modified alkyd urea, catalyzed vinyl, or water
base.
Inks are applied by an offset gravure printing operation
similar to direct roll coating. Most lauan printing inks are pig-
ments dispersed in alkyd resin, with some nitrocellulose added for
4.2.2-20 EMISSION FACTORS 4/81
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4.2.2-21
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better wipe and printability. Water base inks have a good future
for clarity, cost and ecology reasons. After printing, a board
goes through one or two direct or precision roll coaters for
application of the clear protective topcoat. Some topcoats are
synthetic, prepared from solvent soluble alkyd or polyester resins,
urea formaldehyde cross linkings, resins, and solvents.
Natural hardwood plywood panels are coated with transparent or
clear finishes to enhance and protect their face ply of hardwood
veneer. Typical production lines are similar to those for printed
interior paneling, except that a primer sealer is applied to the
filled panel, usually by direct roll coating. The panel is then
embossed and "valley printed" to give a "distressed" or antique
appearance. No basecoat is required. A sealer is also applied
after printing but before application of the topcoat, which may be
curtain coated, although direct roll coating remains the usual
technique.
8 14
Emissions and Controls ' - Emissions of volatile organic
compounds at flat wood coating plants occur primarily from reverse
roll coating of filler, direct roll coating of sealer and basecoat,
printing of wood grain patterns, direct roll or curtain coating of
topcoat(s), and oven drying after one or more of these operations
(see Figure 4.2.2.5-1). All solvent used and not recovered can be
considered potential emissions. Emissions can be calculated from
the factors in Table 4.2.2.1-1, if the coating use is known. Emis-
sions for interior printed panels can be estimated from the factors
in Table 4.2.2.5-1, if the area of coated panels is known.
Waterborne coatings, a process materials change to reduce
emissions, are increasingly used. They can be applied to almost all
flat wood except redwood and, possibly, cedar. The major use of
waterborne flat wood coatings is in the filler and basecoat applied
to printed interior paneling. Limited use has been made of water-
borne materials for inks, groove coats, and topcoats with printed
paneling, and for inks and groove coats with natural hardwood panels.
Ultraviolet curing systems are applicable to clear or
semitransparent fillers, topcoats on particle board coating lines,
and specialty coating operations. Polyester, acrylic, urethane
and alkyd coatings can be cured by this method.
Afterburners can be used to control VOC emissions from baking
ovens, and there would seem to be ample recovered heat to use.
Extremely few flat wood coating operations have afterburners as
addon controls, though, despite the fact that they are a viable
control option for reducing emissions where product requirements
restrict the use of other control techniques.
Carbon adsorption is technically feasible, especially for
specific applications (e.g., redwood surface treatment), but the
use of multicomponent solvents and different coating formulations
it.2.2-22 EMISSION FACTORS 4/81
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4.2.2-23
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in several steps along the coating line have thus far precluded its
use to control flat wood coating emissions and to reclaiming solvents.
The use of low solvent coatings to fill pores and to seal wood has
been demonstrated.
4.2.2.6 Paper Coating
Process Description ' - Paper is coated for various decorative and
functional purposes with waterborne, organic solventborne, or sol-
ventless extruded materials. Paper coating is not to be confused
with printing operations, which use contrast coatings that must
show a difference in brightness from the paper to be visible.
Coating operations are the application of a uniform layer or coating
across a substrate. Printing results in an image or design on the
substrate.
Waterborne coatings improve printability and gloss but cannot
compete with organic solventborne coatings in resistance to weather,
scuff and chemicals. Solventborne coatings, as an added advantage,
permit a wide range of surface textures. Most solventborne coating
is done by paper converting companies that buy paper from mills and
apply coatings to produce a final product. Among the many products
that are coated with solventborne materials are adhesive tapes and
labels, decorated paper, book covers, zinc oxide coated office
copier paper, carbon paper, typewriter ribbons and photographic
film.
Generally used organic solvent formulations are made up of
film forming materials, plasticizers, pigments and solvents. The
main classes of film formers used in paper coating are cellulose
derivatives (usually nitrocellulose) and vinyl resins (usually the
copolymer of vinyl chloride and vinyl acetate). Three common plas-
ticizers are dioctyl phthalate, tricresyl phosphate and castor oil.
The major solvents used are toluene, xylene, methyl ethyl ketone,
isopropyl alcohol, methanol, acetone and ethanol. Although a
single solvent is frequently used, a mixture is often necessary to
obtain the optimum drying rate, flexibility, toughness and abrasion
resistance.
A variety of low solvent coatings, with negligible emissions,
has been developed for some uses to form organic resin films equal
to those of conventional solventborne coatings. They can be applied
up to 1/8 inch thick (usually by reverse roller coating) to products
like artificial leather goods, book covers and carbon paper. Smooth
hot melt finishes can be applied over rough textured paper by heated
gravure or roll coaters at temperatures from 65 to 230°C (150 to
450°F).
Plastic extrusion coating is a type of hot melt coating in
which a molten thermoplastic sheet (usually low or medium density
polyethylene) is extruded from a slotted die at temperatures of up
4.2.2-24 EMISSION FACTORS 4/81
-------
to 315°C (600°F). The substrate and the molten plastic coat are
united by pressure between a rubber roll and a chill roll which
solidifies the plastic. Many products are coated with solventless
extrusion coatings, for example, the polyethylene coated milk
carton.
Figure 4.2.2.6-1 shows a typical paper coating line that uses
organic solventborne formulations. The application device is
usually a reverse roller, a knife or a rotogravure printer. Knife
coaters can apply solutions of much higher viscosity than roll
coaters, thus emitting less solvent per pound of solids applied.
The gravure printer can print patterns or can coat a solid sheet of
color on a paper web.
Ovens may be divided into from two to five temperature zones.
The first zone is usually at about 43°C (110°F) and other zones
have progressively higher temperatures to cure the coating after
most solvent has evaporated. The typical curing temperature is
120°C (250°F), and ovens are generally limited to 200°C (400°F) to
avoid damage to the paper. Natural gas is the fuel most often used
in direct fired ovens, but fuel oil is sometimes used. Some of the
heavier grades of fuel oil can create problems, because SO and
particulate may contaminate the paper coating. Distillate fuel oil
usually can be used satisfactorily. Steam produced from burning
solvent retrieved from an adsorber or vented to an incinerator may
also be used to heat curing ovens.
Emissions and Controls - The main emission points from paper
coating lines are the coating applicator and the oven (see
Figure 4.2.2.6-1). In a typical paper coating plant, about
70 percent of all solvents used are emitted from the coating lines,
with most coming from the first zone of the oven. The other
30 percent are emitted from solvent transfer, storage and mixing
operations and can be reduced through good housekeeping practices.
All solvent used and not recovered or destroyed can be considered
potential emissions.
VOC emissions from individual paper coating plants vary with
size and number of coating lines, line construction, coating
formulation, and substrate composition, so each must be evaluated
individually. VOC emissions can be estimated from the factors in
Table 4.2.2.1-1, if coating use is known and sufficient information
on coating composition is available. Since many paper coating
formulas are proprietary, it may be necessary to have information on
the total solvent used and to assume that, unless a control device
is used, essentially all solvent is emitted. Rarely would as much
as 5 percent be retained in the product.
Almost all solvent emissions from the coating lines can be
collected and sent to a control device. Thermal incinerators have
been retrofitted to a large number of oven exhausts, with primary
4/81 Evaporation Loss Sources 4.2.2-25
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EMISSION FACTORS
4/81
-------
and even secondary heat recovery systems heating the ovens. Carbon
adsorption is most easily adaptable to lines which use single sol-
vent coating. If solvent mixtures are collected by adsorbers, they
usually must be distilled for reuse.
Although available for some products, low solvent coatings are
not yet available for all paper coating operations. The nature of
the products, such as some types of photographic film, may preclude
development of a low solvent option. Furthermore, the more complex
the mixture of organic solvents in the coating, the more difficult
and expensive to reclaim them for reuse with a carbon adsorption
system.
Table 4.2.2.6-1 lists efficiencies of several control devices.
TABLE 4.2.2.6-1. CONTROL EFFICIENCIES FOR PAPER COATING LINES3
Affected Facility Control Efficiency (%)
Coating line Incineration 95
Carbon adsorption 90+ ,
Low solvent coating 80 - 99
a
, Reference 7.
Based on comparison with a conventional coating containing
35% solids and 65% organic solvent by volume.
4.2.2.7 Fabric Coating7'15"16
Process Description - Fabric coating imparts to a fabric substrate
properties such as strength, stability, water or acid repellence,
or appearance. Fabric coating is the uniform application of an
elastomeric or thermoplastic polymer solution, or a vinyl plastisol
or organosol, across 100 percent of at least one side of a supporting
fabric surface or substrate. Coatings are applied by blade, roll
coater, reverse roll coater, and in some instances, by rotogravure
coater. Fabric coating should not be confused with vinyl printing
and topcoating, which occurs almost exclusively on rotogravure
equipment. Textile printing also should not be considered a fabric
coating process.
Products usually fabric coated are rainwear, tents, tarpaulins,
substrates for industrial and electrical tape, tire cord, seals and
gaskets. The industry is primarily small to medium size plants,
many of which are toll coaters, rather than specialists in their
own product lines.
Figure 4.2.2.7-1 is of a typical fabric coating operation.
If the fabric is to be coated with rubber, the rubber is milled with
pigments, curing agents and fillers before being dissolved (mixed)
in a suitable solvent. When other than rubber coatings are used,
milling is rarely necessary.
4/81 Evaporation Loss Sources 4.2.2-27
-------
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Emissions and Controls - The VOC emissions in a fabric coating
plant originate at the mixer, the coating applicator and the oven
(see Figure 4.2.2.7-1). Emissions from these three areas are from
10 to 25 percent, 20 to 30 percent and 40 to 65 percent, respectively.
Fugitive losses, amounting to a few percent, escape during solvent
transfer, storage tank breathing, agitation of mixing tanks, waste
solvent disposal, various stages of cleanup, and evaporation from
the coated fabric after it leaves the line.
The most accurate method of estimating VOC emissions from a
fabric coating plant is to obtain purchase or use records of all
solvents in a specified time period, add to that the amount of
solvent contained in purchased coating solutions, and subtract any
stockpiled solvent, such as cleanup solvent, that is recovered and
disposed of in a nonpolluting manner. Emissions from the actual
coating line without any solvent recovery can be estimated from the
factors in Table 4.2.2.1-1, if coating use is known and sufficient
information on coating composition is available. Because many
fabric coatings are proprietary, it may be necessary for the user
to supply information on the total solvent used and to assume that,
unless a control device is used, all solvent is emitted. To cal-
culate total plant emissions, the coatings mixing losses must be
accounted. These losses can be estimated from the printline
losses by using the relative split of plant emissions between the
mixing area and the printline. For example,
. . / 10% loss from mixing \
Emissions, = Emissions, I 2 I
mixing printline \ 85% loss from printline /
Incineration is probably the best way to control coating
application and curing emissions on coating lines using a variety
of coating formulations. Primary and secondary heat recovery are
likely to be used to help reduce the fuel requirements of the
coating process and, therefore, to increase the economy of incinera-
tion. As with other surface coating operations, carbon adsorption
is most easily accomplished by sources using a single solvent that
can be recovered for reuse. Mixed solvent recovery is, however, in
use in other web coating processes. Fugitive emission controls
include tight covers for open tanks, collection hoods for cleanup
areas, and closed containers for storage of solvent wiping cloths.
Where high solids or waterborne coatings have been developed to
replace conventional coatings, their use may preclude the need for
a control device.
References for Section 4.2.2
1. Products Finishing, 4JL_(6A) :4-54, March 1977.
2. Controlling Pollution from the Manufacturing and Coating of
Metal Products; Metal Coating Air Pollution Control, EPA-
625/3-77-009, U.S. Environmental Protection Agency, May 1977.
4/81 Evaporation Loss Sources 4.2.2-29
-------
3. H.R. Powers, "Economic and Energy Savings through Coating
Selection", The Sherwin-Williams Company, Chicago, IL,
February 8, 1978.
4. Air Pollution Engineering Manual, Second Edition, AP-40, U.S.
Environmental Protection Agency, Research Triangle Park, NC,
May 1973. Out of Print.
5. T.W. Hughes et al., Source Assessment; Prioritization of Air
Pollution from Industrial Surface Coating Operations, EPA-
650/2-75-019a, U.S. Environmental Protection Agency, Research
Triangle Park, NC, February 1975.
6. Control of Volatile Organic Emissions from Existing Stationary
Sources, Volume I; Control Methods for Surface Coating Opera-
TTons, EPA-450/2-76-028, U.S. Environmental Protection Agency,
Research Triangle Park, NC, November 1976.
7. Control of Volatile Organic Emissions from Existing Stationary
Sources, Volume II; Surface Coating of Cans, Coils, Paper
Fabrics, Automobiles, and Light Duty Trucks, EPA-450/2-77-008,
U.S. Environmental Protection Agency, Research Triangle Park,
NC, May 1977.
8. Air Pollution Control Technology Applicable to 26 Sources of
Volatile Organic Compounds, Office of Air Quality Planning and
Standards, U.S. Environmental Protection Agency, Research
Triangle Park, NC, May 27, 1977. Unpublished.
9. Control of Volatile Organic Emissions from Existing Stationary
Sources, Volume IV; Surface Coating for Insulation of Magnet
Wire. EPA-450/2-77-033, U.S. Environmental Protection Agency,
Research Triangle Park, NC, December 1977.
10. Controlled and Uncontrolled Emission Rates and Applicable
Limitations for Eighty Processes, EPA Contract No. 68-02-1382,
TRC of New England, Wethersfield, CT, September 1976.
11. Control of Volatile Organic Emissions from Existing Stationary
Sources, Volume III; Surface Coating of Metal Furniture,
EPA-450/2-77-032, U.S. Environmental Protection Agency,
Research Triangle Park, NC, December 1977.
12. Control of Volatile Organic Emissions from Existing Stationary
Sources, Volume V; Surface Coating of Large Appliances,
EPA-450/2-77-034, U.S. Environmental Protection Agency, Research
Triangle Park, NC, December 1977.
13. Control of Volatile Organic Emissions from Existing Stationary
Sources, Volume VI; Surface Coating of Miscellaneous Metal
Parts and Products, EPA-450/2-78-015, U.S. Environmental
Protection Agency, Research Triangle Park, NC, June 1978.
4.2.2-30 EMISSION FACTORS 4/81
-------
14. Control of Volatile Organic Emissions from Existing Stationary
Sources, Volume VII: Factory Surface Coating of Flat Wood
Interior Paneling, EPA-450/2-78-032, U.S. Environmental
Protection Agency, Research Triangle Park, NC, June 1978.
15. B.H. Carpenter and G.K. Hilliard, Environmental Aspects of
Chemical Use in Printing Operations, EPA-560/1-75-005, U.S.
Environmental Protection Agency, Washington, DC, January 1976.
16. J.C. Berry, "Fabric Printing Definition", Memorandum, Office
of Air Quality Planning and Standards, U.S. Environmental
Protection Agency, Research Triangle Park, NC, August 25, 1980.
17. G.T. Helms, "Appropriate Transfer Efficiencies for Metal
Furniture and Large Appliance Coating", Memorandum, Office of
Air Quality Planning and Standards, U.S. Environmental Pro-
tection Agency, Research Triangle Park, NC, November 28, 1980.
4/81 Evaporation Loss Sources 4.2.2-31
-------
-------
4.3 STORAGE OF ORGANIC LIQUIDS
4.3.1 Process Description
Storage vessels containing organic liquids can be found in
many industries, including: (1) petroleum producing and refining,
(2) petrochemical and chemical manufacturing, (3) bulk storage and
transfer operations, and (4) other industries consuming or pro-
ducing organic liquids. Organic liquids in the petroleum industry,
usually called petroleum liquids, generally are mixtures of chemi-
cals having dissimilar true vapor pressures (for example, gasoline
and crude oil). Organic liquids in the chemical industry, usually
called volatile organic liquids, are composed of pure chemicals or
mixtures of chemicals with similar true vapor pressures (for
example, benzene or a mixture of isopropyl and butyl alcohols).
Five basic tank designs are used for organic liquid storage
vessels: fixed roof, external floating roof, internal floating
roof, variable vapor space and pressure (low and high).
4.3.1.1 Fixed Roof Tanks - A typical fixed roof tank is shown in
Figure 4.3-1. This type of tank consists of a cylindrical steel
shell with a permanently affixed roof, which may vary in design
from cone or dome shaped to flat.
Pressure/vacuum
Valve
Gauge Hatch
Manhole
Manhole
Nozzle (For
submerged fill
or drainage)
4/81
Figure 4.3-1. Typical fixed roof tank.1
Evaporation Loss Sources
4.3-1
-------
Fixed roof tanks are commonly equipped with a pressure/vacuum
vent that allows them to operate at a slight internal pressure or
vacuum. The pressure/vacuum valves prevent the release of vapors
only during very small changes in temperature, pressure or liquid
level. These tanks are generally considered the minimum acceptable
standard for storage of petroleum or volatile organic liquids with
very low vapor pressures.
4.3.1.2 External Floating Roof Tanks - A typical external floating
roof tank is shown in Figure 4.3-2. This type of tank consists of
a cylindrical steel shell equipped with a deck or roof which floats
on the surface of the stored liquid, rising and falling with the
liquid level. The liquid surface is completely covered by the
floating roof, except in the small annular space between the roof
and the tank wall. A seal (or seal system) attached to the roof
contacts the tank wall (except for small gaps, in some cases) and
covers the annular space. The seal slides against the tank wall as
the roof is raised or lowered. The purpose of the floating roof
and the seal (or seal system) is to minimize the amount of
evaporation loss of the stored liquid.
Figure A.3-2. External floating roof tank.
4.3-2
EMISSION FACTORS
4/81
-------
4.3.1.3 Internal Floating Roof Tanks - An internal floating roof
tank has both a permanently affixed roof and a cover that floats on
the liquid surface (contact roof), or that rests on pontoons
several inches above the liquid surface (noncontact roof), inside
the tank. Typical noncontact and contact internal floating roof
tanks are shown in Figures 4.3-3a and 4.3-3b, respectively. The
roof rises and falls with the liquid level. Contact roofs include
(1) aluminum sandwich panel roofs with a honeycomb aluminum core
floating in contact with the liquid, and (2) pan steel roofs float-
ing in contact with the liquid, with or without pontoons.
Noncontact roofs typically consist of an aluminum deck or an alumi-
num grid framework supported above the liquid surface by uubular
aluminum pontoons. Both types of roof, as in the case of external
floating roofs, commonly incorporate flexible perimeter seals or
wipers which slide against the tank wall as the roof moves up and
down. In addition, circulation vents and an open vent at the top
of the fixed roof can be provided to minimize the possibility of
organic vapor accumulation in concentrations approaching the
flammable range.
4.3.1.4 Pressure Tanks There are two classes of pressure tanks
in general use, low pressure (2-15 psig) and high pressure (up to
250 psig or higher). Pressure tanks are generally used for storage
of organic liquids with high vapor pressures and are found in many
sizes and shapes, depending on the operating range of the tank.
High pressure storage tanks can be operated so virtually no
evaporative or working losses occur. Working losses can occur in
low pressure tanks, due to atmospheric venting of the pressure tank
during filling operations.
4.3.1.5 Variable Vapor Space Tanks - Variable vapor space tanks
are equipped with expandable vapor reservoirs to accomodate vapor
volume fluctuations attributable to temperature and barometric
pressure changes. Although variable vapor space tanks are some-
times used independently, they are normally connected to the vapor
spaces of one or more fixed roof tanks. The two most common types
of variable vapor space tank are lifter roof tanks and flexible
diaphragm tanks.
Lifter roof tanks have a telescoping roof that fits loosely
around the outside of the main tank wall. The space between the
roof and the wall is closed by either a wet seal, which consists of
a trough filled with liquid, or a dry seal, which employs a
flexible coated fabric instead of the trough.
Flexible diaphragm tanks use flexible membranes to provide
expandable volume. They may be separate gasholder units or
integral units mounted atop fixed roof tanks.
4/81 Evaporation Loss Sources 4.3-3
-------
Center Vent
Vent
Primary
Seal
Manhole
Rim Plate
Rim Pontoons
Rim
Fontoona
\_ Tank Support Coltaan
with Column Well
Vapor Space
Figure 4.3-3a. Noncontact internal floating roof tank.
Center Vent
Vent-,
Primary
Seal
Manhole
Figure 4.3-3b.
4.3-4
Tank Support Column
with Column. Well
Contact internal floating roof tank.
EMISSION FACTORS 4/81
-------
4.3.2 Emissions and Controls
There are six sources of emissions from organic liquids in
storage: fixed roof breathing losses, fixed roof working losses,
floating roof standing storage losses, floating roof withdrawal
losses, variable vapor space filling losses, and pressure tank
losses.
4.3.2.1 Fixed Roof Tanks - Two significant types of emissions from
fixed roof tanks are breathing losses and working losses.
Breathing loss is the expulsion of vapor from a tank due to vapor
expansion and contraction from changes in temperature and barome-
tric pressure. It occurs in the absence of any liquid level change
in the tank.
The combined loss from filling and emptying is called working
loss. Filling loss is associated with an increase of the liquid
level in the tank. The vapors are expelled from the tank when the
pressure inside the tank exceeds the relief pressure, as a result
of filling. Emptying loss occurs when air drawn into the tank
during liquid removal becomes saturated with organic vapor and
expands, thus exceeding the capacity of the vapor space.
t
Fixed roof tank breathing losses can be estimated from8:
0.68
= 2.26 X 10~2M L. 5 p ) D1-7^0-5^0-5^^ (1)
where: LD = fixed roof breathing loss (Ib/year)
D
M = molecular weight of vapor in storage tank
(Ib/lb mole). See Table 4.3-1
P = true vapor pressure at bulk liquid conditions (psia).
See Note 1
D = tank diameter (ft)
H = average vapor space height, including roof volume
correction (ft). See Note 2
AT = average ambient diurnal temperature change (°F)
Fp = paint factor (dimensionless). See Table 4.3-2
C = adjustment factor for small diameter tanks
(dimensionless). See Figure 4.3-4
Kp = product factor (dimensionless). See Note 3
4/81 Evaporation Loss Sources 4.3-5
-------
TABLE 4.3-1. PHYSICAL PROPERTIES OF TYPICAL ORGANIC LIQUIDS '
Vapor Condensed
molecular Product vapor True vapor pressure in psia at:
rU
O
o
o
rU
0
o
O*
Ut
o
o
00
0
o
I
o
o
U*)
te
o
O
-(*<
*» o
iS
j
H rH
» M
3 00
U *-*.
3 -0
-Cn
3 O
?£
H \O
U
* * o
** en CM rn o o
m m m r- so i--
CM SO 00 O O O
1
«B en o m &
O rH rH r- "-)
I £ S! & 1 7 S
-rt Q- & 06 -d 01
0) OJ OJ -H J3 O
a d a d o QU M
3 -rl -r4 -rt (00)
Oj rH rH rH V d Jri
-H o o o -a
O M (0 DO 3 4-1 4J
4J O O C3 O '-) -}
CM
CM
o
0
o
0
CM
o
o
o
o
o
0
0
m
I
o
en
o
0
o
o
CM
O
2
rH
U
R
rH
rt
4J
a
a
.00019
o
en
o
o
o
0
o
0
o
o
d
0
o
o
o
o
3
O
o
0
o
en
o
§
o
d
CM
O
O
s
o
-d-
o\
p-
o
sO
0
55
rt
o
Residual
cnocncMoocncMoocMfncomfncn^cMOoo
rHOOcoor-«oooooofnoooooo
en d
o Oi-^OCJ^rHrH
d rH rH « )H «U O r- 1 ,.d -d U U D
(D -H 3^ 4jO*J^«)OCJrH(OH J-*
00 >i w +-» S d r-t aj O U >tjSb n
rH OrH4JOO>HOI'Hi-H>J>i>%>*>»~ QJrH
H ^J>.N^^OrHCM>\>sClt,r;jS-fl^' ' 3 r*>
4-1
-------
TABLE 4.3-2. PAINT FACTORS FOR FIXED ROOF TANKS7
Tank color
Paint factors (F )
Paint condition
Roof
Shell
Good
Poor
White
Aluminum (specular)
White
Aluminium (specular)
White
Aluminum (diffuse)
White
Light gray
Medium gray
White
White
Aluminum (specular)
Aluminum (specular)
Aluminum (diffuse)
Aluminum (diffuse)
Gray
Light gray
Medium gray
1.00
1.04
1.16
1.20
1.30
1.39
1.30
1.33
1.40
1.15
1.18
1.24
1.29
1.38
1.46
1.38
1.44*
Estimated from the ratios of the seven preceding paint factors
1.0
u
. 0.8
g
H
g 0.6
o
!°-:
o
/
0
30
10 20
TANK DIAMETER, ft
Figure 4.3-4. Adjustment factor (C) for small diameter tanks.7
4/81 Evaporation Loss Sources A.3-7
-------
Notes: (1)
(2)
(3)
True vapor pressures for organic liquids can be
determined from Figures 4.3-5 or 4.3-6, or Table 4.3-1
The vapor space in a cone roof is equal in volume to a
cylinder which has the same base diameter as the cone
and is one third the height of the cone
For crude oil, KC = 0.65
For all other organic liquids, KC = 1.0
Definitions
True vapor pressure: the equilibrium partial pressure exerted by a
volatile organic liquid as defined by ASTM-D-2879 or as obtained
from standard reference texts.
Reid vapor pressure: the absolute vapor pressure of volatile crude
oil and volatile nonviscous petroleum liquids, except liquified
petroleum gases, as determined by ASTM-D-323-58.
Fixed roof tank working losses can be estimated from7:
L = 2.40 X 10"2 MPKJL, (2)
W w <-
where: L, = fixed roof working loss (lb/103 gal throughput)
M = molecular weight of vapor in storage tank
(Ib/lb mole). See Table 4.3-1
P = true vapor pressure at bulk liquid conditions (psia).
See Note 1
Ky = turnover factor (dimensionless). See Figure 4.3-7
K = product factor (dimensionless). See Note 2
Notes
(1) True vapor pressures for organic liquids can be
determined from Figures 4.3-5 or 4.3-6, or Table 4.3-1
(2) For crude oil, KC = 0.84
For all other organic liquids, KC = 1
.0
The fixed roof working loss (LW) is the sum of the loading and
unloading losses. Special tank operating conditions may result in
losses which are significantly greater or lower than the estimates
provided by Equation 2.
4.3-8
EMISSION FACTORS
4/81
-------
I- 05
1-
E
on [_
Q.
CC
2
<
UJ
D
CC
9
10
11
12
13
14
15
20
, 2
U 4
cc
D
O
Q-
15
140 -,
130
120
110
100
90 -
80
.: 5
_j D
-: a
60 --"-
50 -
40
30
20 ~^
10
- oc
-^ O
- V)
25
4/81
Figure 4.3-5. True vapor pressure (P) of crude oils (2-15 psi RVP).
Evaporation Loss Sources
4.3-9
-------
r 020
- - 030
>- 040
050
r- 0 60
[- 070
h~- 080
^ 090
- 1 oo
120
110
100
90
15 \ - 1 50
DC
D
1/5
o:
O
Q.
200
250
300
350
400
600
700
800
900
[T
D
tn
<
Q
70
60
50
01
I-
: Q
- O
J Q
01
- cc
- o
'- fe
30 -
- 11 0
U- 130
h
£- 140
{7-150
hy- 1*6 0
r- 170
~- 180
^-190
200
r - 21 0
F- 220
F- 230
t~_ 740
SLOPE OF THE ASTM DISTILLATION
CURVE AT 10 PERCENT EVAPORATED
PEG F AT 15 PERCENT MINUS PEG F AT 5 PERCENT
10
IN THE ABSENCE OF DISTILLATION DATA
THE FOLLOWING AVERAGE VALUE OF S MAY BE USED.
MOTOR GASOLINE 3
AVIATION GASOLINE 2
LIGHT NAPHTHA (9 14 LB RVP) 3 5
NAPHTHA (2 8 LB RVP) 25
Null Dashed line illustrates sample problem tor R\T III pounds per square meh gasoline
SOl'Rl I Nomograph drawn Irom (he data ot (he National Bureau ol Standards
o-J
(S -- 1). and /, tO 5 F
Figure 4.3-6. True vapor pressure (P) of refined petroleum liquids
like gasoline and naphthas (1-20psi RVP). 6
4.3-10
EMISSION FACTORS
4/81
-------
1.0
0
0
100
200
300
400
TURNOVERS PER YEAR
ANNUAL THROUGHPUT
TANK CAPACITY
Note: For 36 turnovers per year or less, KN - 1.0
Figure 4.3-7. Turnover factor (KN) for fixed roof tanks,
Several methods are used to control emissions from fixed roof
tanks. Emissions from fixed roof tanks can be controlled by the
installation of a floating roof and seals to minimize evaporation
of product being stored. The control efficiency of this method
ranges from 60 to 92 percent, depending on the type of roof and
seals installed and on the type of organic liquid stored.
A commonly used method, the vapor recovery system, collects
emissions from storage vessels and converts them to liquid product.
Several vapor recovery procedures may be used, including vapor/
liquid absorption, vapor compression, vapor cooling, vapor/solid
adsorption, or a combination of these. The overall control effi-
ciencies of vapor recovery systems are as high as 90 to 98 percent,
depending on the method used, the design of the unit, the composi-
tion of vapors recovered, and the mechanical condition of the
system.
A further mechod of emission control on fixed roof tanks is
thermal oxidation. In a typical thermal oxidation system, the
air/vapor mixture is injected through a burner manifold into the
4/81
Evaporation Loss Sources
4.3-11
-------
combustion area of an incinerator. Control efficiencies for this
system can range from 96 to 99 percent.
4.3.2.2 External and Internal Floating Roof Tanks
4.3.2.2.1 External Floating Roof Tanks - Standing storage loss,
the major element of evaporative loss, results from wind induced
mechanisms as air flows across the top of an external floating roof
tank. These mechanisms may vary, depending upon the types of seals
used to close the annular vapor space between the floating roof and
the tank wall.
Standing storage loss emissions from external floating roof
tanks are controlled by one or two separate seals. The first seal
is called the primary seal, and the other, mounted above the pri-
mary seal, is called the secondary seal. There are three basic
types of primary seal used on external floating roofs, mechanical
(metallic shoe), resilient (nonmetallic), and flexible wiper. The
resilient seal can be mounted to eliminate the vapor space between
the seal and liquid surface (liquid mounted), or to allow a vapor
space between the seal and liquid surface (vapor mounted). A
primary seal serves as a vapor conservation device by closing the
annular space between the edge of the floating roof and the tank
wall. Two configurations of secondary seal are currently avail-
able, shoe mounted and rim mounted. In addition, some primary
seals are protected by a metallic weather shield. Although there
are other seal system designs, the systems described here comprise
the majority in use today.
Withdrawal loss is another source of emissions from external
floating roof tanks. This loss is the vaporization of liquid that
clings to the tank wall and is exposed to the atmosphere when a
floating roof is lowered by withdrawal of liquid.
4.3.2.2.2 Internal Floating Roof Tanks - Internal floating roof
tanks generally have the same sources of emissions as external
floating roof tanks. Standing storage and wetting losses are two
sources of emissions from these tanks. Fitting losses, from pene-
trations in the roof by deck fittings, roof column supports, or
other openings, can also account for emissions from internal
floating roof tanks.
Typical internal floating roofs incorporate two types of
primary seal, resilient foam filled and wiper. Similar to those
employed in external floating roof tanks, these seals close the
annular vapor space between the edge of the floating roof and the
tank wall.
4.3-12 EMISSION FACTORS 4/81
-------
4.3.2.3 Emission Calculations for External and Internal Floating
Roof Tanks: Background Information - The following equation is
used to calculate standing storage loss emissions from both external
floating roof and internal floating roof storage tanks:
Where: (1) LQ is the standing storage loss (Ib/year)
O
(2) K9 and N are interdependent factors that relate the
type of tank, the design of the tank seal and local
wind velocity, V, to standing storage loss
..'-
(3) P , the vapor pressure function, is a theoretically
derived function which establishes the effect of stock
volatility on standing storage loss
(4) D, the tank diameter, is linear with standing storage
loss as verified by field tank testing
(5) My, the vapor molecular weight, provides standing
storage loss estimates in mass terms
(6) Kp, the product factor, establishes the relationship
of standing storage loss to the type of stored organic
liquid
(7) E_, the secondary seal factor, establishes the
effectiveness of secondary seals in controlling
standing storage loss
The above factors were developed from emissions data obtained from
field and pilot test studies conducted by oil companies, manufac-
turers, industry groups, and regulatory agencies, on both internal
floating roof and external floating roof storage tanks. The
largest set of data, concerning external floating roof tanks stor-
ing petroleum liquids, was analyzed by the American Petroleum
Institute (API), and the results published in Reference 6. The K,,
and N values for the primary only and primary/secondary seal sys-
tems shown in Table 4.3-3 are the same as those published in
Reference 6 for seals with "average" gaps.
Due to the small amount of emissions data available for
internal floating roof tanks storing volatile organic liquids and
petroleum liquids, and external floating roof tanks storing vola-
tile organic liquids, !( and N factors for these cases were
developed from correlations between those available data and the
data used to develop the K<, and N values published in Reference 6.
These correlations were usea to develop Kc and N factors for
o
4/81 Evaporation Loss Sources 4.3-13
-------
TABLE 4.3-3. SEAL RELATED FACTORS FOR
EXTERNAL FLOATING ROOF TANKS3'
Seal Type K_ N
O
Metallic Shoe Seal
Primary seal only 1.2 1.5
With shoe mounted
secondary seal 0.8 1.2
With rim mounted
secondary seal 0.2 1.0
Liquid Mounted Resilient
Seal
Primary seal only 1.1 1.0
With weather shield 0.8 0.9
With rim mounted
secondary seal 0.7 0.4
Vapor Mounted Resilient
Seal
Primary seal only 1.2 2.3
With weather shield 0.9 2.2
With rim mounted
secondary seal 0.2 2.6
ft
Based on emissions from tank seal system with
emissions control devices (roof, seals, etc.)
in reasonably good working condition, no visi-
ble holes, tears or unusually large gaps between
the seals and the tank wall.
Factors for secondary seals are appropriate
only for external floating roof tanks storing
petroleum liquids.
primary seal only cases. Analysis of the available test data shows
the secondary seal control efficiency to range from 55 to 93 per-
cent. Based on this information, the secondary seal factor, E,-,,
was developed. For correct application of the secondary seal
factor, a visual inspection of the tank and seal of interest is
suggested. If the tank and seal are found in good condition (no
tears or holes in the seal and no apparent large gaps at the tank
wall/seal junction), a value of E = 0.25 (75 percent control
efficiency) is recommended.8
4.3-14 EMISSION FACTORS 4/81
-------
Further analysis of all available data shows that, for any
seal system, emissions from tanks storing volatile organic liquids
were generally ten times those of the same tank type storing petro-
leum liquids. Based on this information, the value of the product
factor, Kp, was determined to be U) for tanks storing volatile
organic liquids.
Due to the small amount of data available, the method and
factors used to calculate standing storage loss emissions from
external floating roof tanks storing volatile organic liquids, and
internal floating roof tanks storing both petroleum liquids and
volatile organic liquids, are considered interim methods, awaiting
further data development.
4.3.2.3.1 External Floating Roof Tank Standing Storage Loss
Calculations6 - The standing storage loss from external floating
roof tanks can be estimated from the following equation:
IVNP*DMVKCEF (3)
Ls = Ks
Where: ! = standing storage loss (Ib/yr)
K_ = seal factor (lb-mole/(ft (mi/hr) yr)). See Note 1
o
V = average wind speed at tank site (mi/hr). See Note 2
N = seal related wind speed exponent (dimensionless). See
Note 1
/v
P = vapor pressure function (dimensionless). See Note 3
P = true vapor pressure at average actual
organic liquid storage temperature (psia)
P. = average atmospheric pressure at tank
location (psia)
D = tank diameter (ft)
y = average vapor molecular weight (Ib/lb-mole). See
Note 4
K- = product factor (dimensionless). See Note 5
E- = secondary seal factor. See Note 6
r
4/81 Evaporation Loss Sources 4.3-15
-------
Notes: (1) For petroleum liquid storage: K,, and N for both
primary only and primary/secondary seal systems are
found in Table 4.3-3
For volatile organic liquid storage: only the Kq and
N values of Table 4.3-3 for the primary only seal
systems are employed. If the storage tank of interest
has both a primary and secondary seal, use the Kq and
N value for the particular primary seal of interest
and the appropriate E_ value. See Note 6
r
(2) If the wind speed at the tank site is not available,
wind speed data from the nearest local weather station
may be used as an approximation
..»-
(3) P can be calculated or read directly from
Figure 4.3-8. True vapor pressures for organic
liquids can be determined from Figures 4.3-5 or 4.3-6,
or Table 4.3-1. If average actual organic liquid
storage temperature, T^, is unknown, the average
storage temperature can oe estimated from the average
ambient temperature T.(F) (available from local
weather service data), adjusted by the tank paint
color factor. See Table 4.3-4
(4) The molecular weight of the vapor, M.., can be
determined by Table 4.3-1, analysis of vapor samples,
or by calculation from the liquid composition. A
typical value of 64 Ib/lb-mole can be assumed for
gasoline, and a value of 50 Ib/lb-mole can be assumed
for U.S. midcontinental crude oils
(5) For all petroleum liquids except crude oil: Kp = 1.0
For crude oil: K = 0.4
For all volatile organic liquids: K~ = 10.0
L*
i _.j___ _ o -
any seal system: £ = 1.0
r
(6) For petroleum liquid storage with
any seal system:
For volatile organic liquid storage
with a primary only seal system: £ = 1.0
with a primary/secondary seal system: £ = 0.07-0.45
(A value of 0.25
is recommended
for tanks and
seals in good
condition.)
4.3-16 EMISSION FACTORS 4/81
-------
g
H-
o
u_
£ 01
a.
oc
<
u
9
8
7
6
5
4
3
2
1
09
08
07
06
05
04
03
.02
01
-
-
-
-
-
E
=
-
-
-
-
-
-
|/
E/
~|
/
I
/
/
\
/
/
/
I
1
1
X
p
VWi
At
1
X
/
ll
fre
nospher
ic pressi
1
X
\14.7
X
X
}
P\"
ire = 1
i
4.7^
* 7 poun
I
X
\
r)
ds per sc
1
X
|uare in
I
A
/
:h ahsoli
i
f
/-
/-
/ -1
-
-
5
-
-
-
-
-
jte
1 ~~
1 U
9
8
7
6
5
4
3
2
01
09
08
07
06
05
04
03
02
nm
1 2 3 4 5 6 7 8 9 10 11 12
TRUE VAPOR PRESSURE, P(psia)
NOTE Dashed line illustrates sample problem for P = 5 4 pounds per square inch absolute
Figure 4.3-8. Vapor pressure function (P*). 6
13 14
4/81
Evaporation Loss Sources
4.3-17
-------
TABLE 4.3-4. AVERAGE STORAGE TEMPERATURE
(T0) AS A FUNCTION OF TANK PAINT COLOR3
Average storage
Tank color Temperature, T_ (F)
White T. + 0
A
Aluminum T + 2.5
A
Gray TA + 3.5
Black T. + 5.0
A
a
Reference 6.
4.3.2.3.2 Internal Floating Roof Tank Standing Storage Loss
Calculations - Standing storage loss emissions from internal
floating roof tanks are best estimated from Equation 36'8:
where: K_ = 0.7 for all seal systems
o
N = 0.4 for all seal systems
Kr = 1.0 for petroleum liquid storage
L>
Kr = 10.0 for volatile organic liquid storage
Li
E_ = 1.0 for primary only seal systems
r
E = 0.07 - 0.45 for primary/ secondary seal systems (A
value of 0.25 is recommended for tanks and seals in
good condition.)
4.3.2.3.3 Withdrawal Loss from External Floating Roof and Internal
Floating Roof Storage Tanks6 - The withdrawal loss from external
floating roof and internal floating roof storage tanks can be
estimated using Equation 4.
(0.943)QCWT
A. 3-18 EMISSION FACTORS 4/81
-------
Where: L, = withdrawal loss (Ib/yr)
Q = average throughput (barrel (bbl)/yr; 1 bbl = 42 U.S.
gallons)
C = shell clingage factor (bbl/1000 ft2). See Table 4.3-5
WT = average organic liquid density (Ib/gal). See Note 1
Li
D = tank diameter (ft).
Notes: (1) If WT is not known, an average value of 6.1 Ibs/
gallon can be assumed for gasoline. An average value
cannot be assumed for crude oil, since densities are
highly variable
(2) The constant, 0.943, has dimensions of (1000 ft3 x
gal/bbl2)
4.3.2.3.4 Total Loss from External Floating Roof and Internal
Floating Roof Storage Tanks6 - The total loss from external float-
ing roof and internal floating roof storage tanks in Ib/yr can be
estimated from Equation 5.
LT(lb/yr) = Lg (Ib/yr) +
(5)
Where: L_, = total loss
L = standing storage loss
o
LW
= withdrawal loss
TABLE 4.3-5. AVERAGE CLINGAGE FACTORS (C)
(bbl/1000 ft2)3
Shell Condition
Product Light rust
Gasoline 0.0015
Crude oil 0.0060
Dense rust Gunite
0.0075 0.
0.030 0.
lined
15
60
o
Reference 6.
4/81
Evaporation Loss Sources
4.3-19
-------
4.3.2.4 Pressure Tanks Losses occur in low pressure tanks during
withdrawal and filling operations when atmospheric venting occurs.
High pressure tanks are considered closed systems, with virtually
no emissions. Vapor recovery systems are often found on low pres-
sure tanks. Fugitive losses are also associated with pressure
tanks and their equipment, but with proper system maintenance,
these losses are considered insignificant. No appropriate corre-
lations are available for estimating vapor losses from pressure
tanks.
4.3.2.5 Variable Vapor Space Tanks3'4 - Variable vapor space
filling losses result when vapor is displaced by liquid during
filling operations. Since the variable vapor space tank has an
expandable vapor storage capacity, this loss is not as large as the
filling loss associated with fixed roof tanks. Loss of vapor
occurs only when the vapor storage capacity of the tank is
exceeded.
Variable vapor space system filling losses can be estimated
from:
Ly = (2.40 x 10-2)^-((V!)-(0.25 V2N)) (6)
Where: L., = variable vapor space filling loss (lb/103 gal
throughput)
M = molecular weight of vapor in storage tank
(Ib/lb-mole). See Table 4.3-1
P = true vapor pressure at bulk liquid conditions (psia).
See Note 1
Vt = volume of liquid pumped into system; throughput (bbl)
V£ = volume expansion capacity of system (bbl). See Note 2
N = number of transfers into system (dimensionless). See
Note 3
Notes: (1) True vapor pressure for organic liquids can be
determined from Figures 4.3-5 or 4.3-6, or Table 4.3-1
(2) V2 is the volume expansion capacity of the variable
vapor space achieved by roof lifting or diaphragm
flexing
(3) N is the number of transfers into the system during
the time period that corresponds to a throughput of Vj
4.3-20 EMISSION FACTORS 4/81
-------
The accuracy of Equation 6 is not documented. Special tank
operating conditions may result in actual losses which are signifi-
cantly different from the estimates provided by Equation 6. It
should also be noted that, although not developed for use with
heavier petroleum liquids such as kerosenes and fuel oils, the
equation is recommended for use with heavier petroleum liquids in
the absence of better data.
Vapor recovery systems capture organic vapors displaced during
filling operations and recover the organic vapors by refrigeration,
absorption, adsorption and/or compression. Control efficiencies
range from 90 to 98 percent, depending on the nature of the vapors
and on the recovery equipment used.
4.3.3 Sample Calculations -
4.3.3.1 Problem I: Estimate the total standing storage loss for
3 months based on data observed during the months of March, April
and May, given the following information:
Tank description:
Stored product:
External floating roof tank with a
mechanical shoe primary seal in good con-
dition; 100 ft. diameter; tank shell
painted aluminum color.
Motor gasoline (petroleum liquid); Reid
vapor pressure, 10 psia; 6.1 Ib/gal liquid
density; no vapor or liquid composition
given; 375,000 bbl throughput for the
3 months.
Ambient conditions: 60°F average ambient temperature for the
3 months; 10 mi/hr average wind speed at
tank site for the 3 months; assume
14.7 psia atmospheric pressure.
Standing Storage Loss - Calculate the yearly standing storage loss
from Equation 3.
Ls(lb/yr) = Kg^pfcDM^Ej. (3)
The variables in Equation 3 can be determined as follows:
Kg = 1.2 (from Table 4.3-3, for a welded tank with a
mechanical shoe primary seal)
N = 1.5 (from Table 4.3-3, for a welded tank with a
mechanical shoe primary seal)
4/81
Evaporation Loss Sources
4.3-21
-------
V = 10 mi/hr (given)
V1* = (10)1-5 = 32
TA = 60°F (given)
T = 62.5°F (from Table 4.3-4, for an aluminum color tank
in good condition and T = 60°F)
A
RVP = 10 psia (given)
P = 5.4 psia (from Figure 4.3-6, for 10 psia Reid vapor
pressure gasoline and Tc = 62.5°F)
O
PA = 14.7 psia (assumed)
A
M
\14.7/
5.4\ °-<
14.7 /
0.114
(from Equation 3 or from Figure 4.3-8 for P =5.4
psia)
D = 100 ft (given)
M-, = 64 Ib/lb-mole (assumed for gasoline)
Kr = 1.0 (for an external floating roof storage tank
storing a petroleum liquid)
E_ = 1.0 (for an external floating roof storage tank
storing a petroleum liquid)
To calculate yearly standing storage loss, based on the
3 month data, multiply the K , V , P*, D, My, K , and E values, as
in Equation 3. To calculate emissions for time intervals other
than 1 year, a yearly standing storage loss must be initially
calculated and the resulting emissions scaled according to the
desired time interval.
L (Ib/yr) = (1.2)(32)(0.114)(100)(64)(1.0) (1.0) ^
= 28,016 Ib/yr
To calculate the standing storage loss for the 3 months,
divide L0 in (Ib/yr) by 4 (3 months is 1/4 of a year).
o
_ (28,016) _ ?004 lbs for 3 months
O *t
4.3-22 EMISSION FACTORS 4/81
-------
Withdrawal Loss - Calculate the withdrawal loss from Equation 4.
QCW
Lw(lb/yr) = (0.943) -^ (4)
The variables in Equation 4 can be determined as follows:
Q = 3.75 x 105 bbl for 3 months = 1.5 x 106 bbl/yr (given)
C = 0.0015 bbl/1000 ft2 (from Table 4.3-5, for gasoline in
a steel tank with light rust)
WT = 6.1 Ib/gal (given)
D = 100 ft (given)
To calculate yearly withdrawal loss, use Equation 4.
Lw(lb/yr) = (0.943K1.5 x 10«)(0.0015)(6.1) (4)
= 129 Ib/yr
To calculate withdrawal loss for 3 months, divide by 4.
LW = 129/4 = 32 Ibs for 3 months
Total Loss - Calculate the total loss in (Ib/yr) from Equation 5.
LT(lb/yr) = Ls (Ib/yr) + L^lb/yr) (5)
L (Ib/yr) =(28,016) + (129) = 28,145 Ib/yr
To calculate the total loss for 3 months, divide by 4.
LT = 28>*45 = 7036 Ibs for 3 months
4.3.3.2 Problem II: Estimate the yearly standing storage loss
from an external floating roof tank storing a volatile organic
liquid (excluding withdrawal loss) given the following information:
Tank description same as in Problem I, except the tank now is
equipped with a mechanical shoe seal and a secondary seal.
Stored product: Benzene.
Ambient Conditions: Same as in Problem I.
4/81 Evaporation Loss Sources 4.3-23
-------
Standing Storage Loss
Ls(lb/yr) = KgVVDMyK^ (3)
The variables in Equation 3 are the same as in Problem I, with the
following exceptions:
P = 1.2 psia (from Table 4.3-1 for benzene at 60°F)
PA = 14.7 psia (assumed)
= 0.021
/1 ?^ .51 2
i
My = 78 Ib/lb-mole (from Table 4.3-1)
K_ = 10 (given for calculation of volatile organic liquid
emissions from external floating roof tanks)
Ep = .25 (for tank and seals in good condition)
lo calculate the yearly standing storage loss, multiply the
K_, v , P*, D, My, Kp, and E,., values as in Equation 3.
Lq(lb/yr) = (1.2)(32)(0.021)(100)(78)(10)(.25)
= 15,725 Ib/yr
References for Section 4.3
1. Benzene Emissions from Benzene Storage Tanks - Background
Information for Proposed Standards, EPA-450/3-80-034a,
U. S. Environmental Protection Agency, Research Triangle Park,
NC, September 1980.
2. Control of Volatile Organic Emissions from Petroleum Liquid
Storage in External Floating Roof Tanks, EPA-450/2-78-047,
U. S. Environmental Protection Agency, Research Triangle Park,
NC, December 1978.
3. Use of Variable Vapor Space Systems To Reduce Evaporation Loss,
Bulletin No. 2520, American Petroleum Institute, New York, NY,
1964.
4. Petrochemical Evaporation Loss from Storage Tanks, Bulletin
No. 2523, American Petroleum Institute, New York," NY, 1969.
4.3-24 EMISSION FACTORS 4/81
-------
5. Henry C. Harriett, et. al. , Properties of Aircraft Fuels,
NACA-TN 3276, Lewis Flight Propulsion Laboratory, Cleveland,
OH, August 1956.
6. Evaporation Loss from External Floating Roof Tanks, Bulletin
No. 2517, American Petroleum Institute, Washington, DC, 1980.
7. Evaporation Loss from Fixed Roof Tanks, Bulletin No. 2518,
American Petroleum Institute, Washington, DC, 1962.
8. Background Documentation for Storage of Organic Liquids, EPA
Contract No. 68-02-3174, TRW Environmental, Inc., Research
Triangle Park, NC, May 1981.
4/81 Evaporation Loss Sources 4.3-25
-------
-------
4.6 SOLVENT DECREASING
4.6.1 General1'2
Solvent degreasing (or solvent cleaning) is the physical
process of using organic solvents to remove grease, fats, oils, wax
or soil from various metal, glass or plastic items. The types of
equipment used in this method are categorized as cold cleaners,
open top vapor degreasers, or conveyorized degreasers. Nonaqueous
solvents such as petroleum distillates, chlorinated hydrocarbons,
ketones and alcohols are used. Solvent selection is based on the
solubility of the substance to be removed and on the toxicity,
flammability, flash point, evaporation rate, boiling point, cost
and several other properties of the solvent.
The metalworking industries are the major users of solvent
degreasing, i.e., automotive, electronics, plumbing, aircraft,
refrigeration and business machine industries. Solvent cleaning is
also used in industries such as printing, chemicals, plastics,
rubber, textiles, glass, paper and electric power. Most repair
stations for transportation vehicles and electric tools use solvent
cleaning at least part of the time. Many industries use water
based alkaline wash systems for degreasing, and since these systems
emit no solvent vapors to the atmosphere, they are not included in
this discussion.
Cold Cleaners - The two basic types of cold cleaners are maintenance
and manufacturing. Cold cleaners are batch loaded, nonboiling
solvent degreasers, usually providing the simplest and least
expensive method of metal cleaning. Maintenance cold cleaners are
smaller, more numerous and generally using petroleum solvents as
mineral spirits (petroleum distillates and Stoddard solvents).
Manufacturing cold cleaners use a wide variety of solvents, which
perform more specialized and higher quality cleaning with about
twice the average emission rate of maintenance cold cleaners. Some
cold cleaners can serve both purposes.
Cold cleaner operations include spraying, brushing, flushing
and immersion. In a typical maintenance cleaner (Figure 4.6-1),
dirty parts are cleaned manually by spraying and then soaking in
the tank. After cleaning, the parts are either suspended over the
tank to drain or are placed on an external rack that routes the
drained solvent back into the cleaner. The cover is intended to be
closed whenever parts are not being handled in the cleaner. Typical
manufacturing cold cleaners vary widely in design, but there are
two basic tank designs, the simple spray sink and the dip tank. Of
these, the dip tank provides more thorough cleaning through
immersion, and often is made to improve cleaning efficiency by
agitation. Small cold cleaning operations may be numerous in urban
areas. However, because of the small quantity of emissions from
each operation, the large number of individual sources within an
urban area, and the application of small cold cleaning to industrial
4/81 Evaporation Loss Sources 4.6-1
-------
cc
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4.6-2
HUSSION FACTORS
4/81
-------
uses not directly associated with degreasing, it is difficult to
identify individual small cold cleaning operations. For these
reasons, factors are provided in Table 4.6-1 to estimate emissions
from small cold cleaning operations over large urban geographical
areas. Factors in Table 4.6-1 are for nonmethane VOC and include
25 percent 1,1,1 - trichloroethane, methylene chloride and
trichlorotrifluoroethane.
TABLE 4.6-1. NONMETHANE VOC EMISSIONS FROM SMALI
COLD CLEANING DEGREASING OPERATIONS3
EMISSION FACTOR RATING: C
Per capita
Operating period emission factor
Annual 1.8 kg
4.0 Ib
Diurnal 5.8 g
0.013 Ib
o
, Reference 3.
Assumes a 6 day operating week (313 days/yr).
Open Top Vapor Systems - Open top vapor degreasers are batch loaded
boiling degreasers that clean with condensation of hot solvent
vapor on colder metal parts. Vapor degreasing uses halogenat«d
solvents (usually perchloroethylene, trichloroethylene, or 1,1,1-tri-
chloroethane), because they are not flammable and their vapors are
much heavier than air.
A typical vapor degreaser (Figure 4.6-1) is a sump containing
a heater that boils the solvent to generate vapors. The height of
these pure vapors is controlled by condenser coils and/or a water
jacket encircling the device. Solvent and moisture condensed on
the coils are directed to a water separator, where the heavier
solvent is drawn off the bottom and is returned to the vapor degreaser.
A "freeboard" extends above the top of the vapor zone to minimize
vapor escape. Parts to be cleaned are immersed in the vapor zone,
and condensation continues until they are heated to the vapor
temperature. Residual liquid solvent on the parts rapidly evaporates
as they are slowly removed from the vapor zone. Lip mounted exhaust
systems carry solvent vapors away from operating personnel. Cleaning
action is often increased by spraying the parts with solvent below
the vapor level or by immersing them in the liquid solvent bath.
Nearly all vapor degreasers are equipped with a water separator
which allows the solvent to flow back into the degreaser.
Emission rates are usually estimated from solvent consumption
data for the particular degreasing operation under consideration.
4/81 Evaporation Loss Sources 4.6-3
-------
Solvents are often purchased specifically for use in degreasing and
are not used in any other plant operations. In these cases, purchase
records provide 'the necessary information, and an emission factor
of 1,000 kg of volatile organic emissions per metric ton of solvent
purchased can be applied, based on the assumption that all solvent
purchased is eventually emitted. When information on solvent
consumption is not available, emission rates can be estimated if
the number and type of degreasing units are known. The factors in
Table 4.6-2 are based on the number of degreasers and emissions
produced nationwide and may be considerably in error when applied
to one particular unit.
The expected effectiveness of various control devices and
procedures is listed in Table 4.6-3. As a first approximation,
this efficiency can be applied without regard for the specific
solvent being used. However, efficiencies are generally higher for
more volatile solvents. These solvents also result in higher
emission rates than those computed from the "average" factors
listed in Table 4.6-2.
Conveyorized Degreasers - Conveyorized degreasers may operate with
either cold or vaporized solvent, but they merit separate
consideration because they are continuously loaded and are almost
always hooded or enclosed. About 85 percent are vapor types, and
15 percent are nonboiling.
1-3
4.6.2 Emissions and Controls
Emissions from cold cleaners occur through (1) waste solvent
evaporation, (2) solvent carryout (evaporation from wet parts),
(3) solvent bath evaporation, (4) spray evaporation, and (5) agitation
(Figure 4.6-1). Waste solvent loss, cold cleaning's greatest
emission source, can be reduced through distillation and transport
of waste solvent to special incineration plants. Draining cleaned
parts for at least 15 seconds reduces carryout emissions. Bath
evaporation can be controlled by using a cover regularly, by allowing
an adequate freeboard height and by avoiding excessive drafts in
the workshop. If the solvent used is insoluble in, and heavier
than, water, a layer of water two to four inches thick covering the
halogenated solvent can also reduce bath evaporation. This is
known as a "water cover". Spraying at low pressure also helps to
reduce solvent loss from this part of the process. Agitation
emissions can be controlled by using a cover, by agitating no
longer than necessary, and by avoiding the use of agitation with
low volatility solvents. Emissions of low volatility solvents
increase significantly with agitation. However, contrary to what
one might expect, agitation causes only a small increase in emissions
of high volatility solvents. Solvent type is the variable which
most affects cold cleaner emission rates, particularly the volatility
at operating temperatures.
4.6-4 EMISSION FACTORS 4/81
-------
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TABLE 4.6-3. PROJECTED EMISSION REDUCTION FACTORS FOR SOLVENT DECREASING
Cold Vapor Conveyorized
cleaner degreaser degreaser
System
Control devices
Cover or enclosed design
Drainage facility
Water cover, refrigerated chiller, carbon
adsorption or high freeboard
Solid, fluid spray stream
Safety switches and thermostats
XXX
XXX
X
X
X X
X
X
X
X
X
X
X
Emission reduction from control devices (%)
Operating procedures
Proper use of equipment
Use of high volatility solvent
Waste solvent reclamation
Reduced exhaust ventilation
Reduced conveyor or entry speed
Emission reduction from operating
procedures(%)
Total emission reduction(%)
13-38 NAU
X
X
15-45 NAd
20-40 30-60
X
X
X
X
X
X
X
X
X
40-60
X
X
X
15-35 20-40 20-30 20-30
28-83e 55-69f 30-60 45-75 20-30 50-70
Reference 2. Ranges of emission reduction present poor to excellent compliance.
X indicates devices or procedures which will effect the given reductions. Letters
A and B indicate different control device circumstances. See Appendix B of
bReference 2.
Only one of these major control devices would be used in any degreasing system. System B
could employ any of them. Vapor degreaser system B could employ any except water cover.
Conveyorized degreaser system B could employ any except water cover and high freeboard.
, If agitation by spraying is used, the spray should not be a shower type.
Breakout between control equipment and operating procedures is not available.
eA manual or mechanically assisted cover would contribute 6-18% reduction; draining
parts 15 seconds within the degreaser, 7-20%; and storing waste solvent in containers,
fan additional 15-45%.
Percentages represent average compliance.
As with cold cleaning, open top vapor degreasing emissions
relate heavily to proper operating methods. Most emissions are due
to (6) diffusion and convection, which can be reduced by using an
automated cover, by using a manual cover regularly, by spraying
below the vapor level, by optimizing work loads or by using a
refrigerated freeboard chiller (for which a carbon adsorption unit
would be substituted on larger units). Safety switches and
thermostats that prevent emissions during malfunctions and abnormal
operation also reduce diffusion and convection of the vaporized
solvent. Additional sources are (7) solvent carryout, (8) exhaust
systems and (9) waste solvent evaporation. Carryout is directly
affected by the size and shape of the workload, by racking of parts
and by cleaning and drying time. Exhaust emissions can be nearly
eliminated by a carbon adsorber that collects the solvent vapors
for reuse. Waste solvent evaporation is not so much a problem with
4.6-6
EMISSION FACTORS
4/81
-------
vapor degreasers as it is with cold cleaners, because the halogenated
solvents used are often distilled and recycled by solvent recovery
systems.
Because of their large workload capacity and the fact that
they are usually enclosed, conveyorized degreasers emit less solvent
per part cleaned than do either of the other two types of degreaser.
More so than operating practices, design and adjustment are major
factors affecting emissions, the main source of which is carryout
of vapor and liquid solvents.
References for Section 4.6
1. P.J. Marn, et al., Source Assessment; Solvent Evaporation -
Decreasing, EPA Contract No. 68-02-1874. Monsanto Research
Corporation, Dayton, OH, January 1977.
2. Jeffrey Shumaker, Control of Volatile Organic Emissions from
Solvent Metal Cleaning, EPA-450/2-77-022, U.S. Environmental
Protection Agency, Research Triangle Park, NC, November 1977.
3. W.H. Lamason, "Technical Discussion of Per Capita Emission
Factors for Several Area Sources of Volatile Organic Compounds",
Office of Air Quality Planning and Standards, U.S. Environmental
Protection Agency, Research Triangle Park, NC, March 15, 1981,
unpublished.
4. K.S. Suprenant and D.W. Richards, Study To Support New Source
Performance Standards for Solvent Metal Cleaning Operations,
EPA Contract No. 68-02-1329, Dow Chemical Company, Midland,
MI, June 1976.
4/81 Evaporation Loss Sources 4.6-7
-------
-------
4.9 GRAPHIC ARTS
4.9.1 General
Process Description - The term "graphic arts" as used here means
four basic processes of the printing industry: web offset lithography,
web letterpress, rotogravure and flexography. Screen printing and
manual and sheet fed techniques are not included in this discussion.
Printing may be performed on coated or uncoated paper and on
other surfaces, as in metal decorating and some fabric coating
(see Section 4.2, Industrial Surface Coating). The material to
receive the printing is called the substrate. The distinction
between printing and paper coating, which may employ rotogravure or
lithographic methods, is that printing invariably involves the
application of ink by a printing press. However, printing and
paper coating have these elements in common: application of a
relatively high solvent content material to the surface of a moving
web or film, rapid solvent evaporation by movement of heated air
across the wet surface, and solvent laden air exhausted from the
system.
Printing inks vary widely in composition, but all consist of
three major components: pigments, which produce the desired colors
and are composed of finely divided organic and inorganic materials;
binders, the solid components that lock the pigments to the substrate
and are composed of organic resins and polymers or, in some inks,
oils and rosins; and solvents, which dissolve or disperse the
pigments and binders and are usually composed of organic compounds.
The binder and solvent make up the "vehicle" part of the ink. The
solvent evaporates from the ink into the atmosphere during the
drying process.
Web Offset Lithography - Lithography, the process used to produce
about 75 percent of books and pamphlets and an increasing number of
newspapers, is characterized by a planographic image carrier
(i.e., the image and nonimage areas are on the same plane). The
image area is ink wettable and water repellant, and the nonimage
area is chemically repellant to ink. The solution used to dampen
the plate may contain 15 to 30 percent isopropanol, if the Dalgren
dampening system is used.^ When the image is applied to a rubber
covered "blanket" cylinder and then transferred onto the substrate,
the process is known as "offset" lithography. When a web (i.e., a
continuous roll) of paper is employed with the offset process, this
is known as web offset printing. Figure 4.9-1 illustrates a web
offset lithography publication printing line. A web newspaper
printing line contains no dryer, because the ink contains very
little solvent, and somewhat porous paper is generally used.
Web offset employs "heatset" (i.e., heat drying offset) inks
that dry very quickly. For publication work the inks contain about
40 percent solvent, and for newspaper work 5 percent solvent is
used. In both cases, the solvents are usually petroleum derived
4/81 Evaporation Loss Sources 4.9-1
-------
GAS
j THERMAL OR
CATALYTIC '
INCINERATOR
I
TOR I INK
TOR| 1 THERM
- J__I _ _
I HEAT I
INK SOLVENT AND
'HERMAL DEGRADATION
PRODUCTS
1 EXCHANGER 1
1 #1 1
EXHAUST FAN
SHELL AND
FLAT TUBE
HEAT
EXCHANGER
COMBUSTION
PRODUCTS,
UNBURNED
ORGANICS,
O2 DEPLETED
AIR
FRESH AIR
| FILTER || FILTER)
FAN
HEATSET
INK
INK SOLVENT AND
THERMAL DEGRADATION
PRODUCTS
WASHUP
SOLVENTS.
WEB
WATER AND
ISOPROPANOL
VAPOR
1
WASHUP
SOLVENTS
FAN
AIR AND SMOKE
PRINTED WEB
TT
* WATER AND
ISOPROPANOL VAPOR
AIR
AIR
WATER ISOPROPANOL
(WITH DALGREN
DAMPENING SYSTEM)
Figure 4.9-1. Web offset lithography publication printing line emission point;;.
11
4.9-2
EMISSION FACTORS
4/81
-------
hydrocarbons. In a publication web offset process, the web is
printed on both sides simultaneously and passed through a tunnel or
floater dryer at about 200-290°C (400-500°F) . The dryer may be hot
air or direct flame. Approximately 40 percent of the incoming
solvent remains in the ink film, and more may be thermally degraded
in a direct flame dryer. The web passes over chill rolls before
folding and cutting. In newspaper work no dryer is used, and most
of the solvent is believed to remain in the ink film on the paper.^
Web Letterpress - Letterpress is the oldest form of moveable type
printing, and it still dominates in periodical and newspaper publish-
ing, although numerous major newspapers are converting to web offset.
In letterpress printing, the image area is raised, and the ink is
transferred to the paper directly from the image surface. The
image carrier may be made of metal or plastic. Only web presses
using solventborne inks are discussed here. Letterpress newspaper
and sheet fed printing use oxidative drying inks, not a source of
volatile organic emissions. Figure 4.9-2 shows one unit of a web
publication letterpress line.
Publication letterpress printing uses a paper web that is
printed on one side at a time and dried after each color is applied.
The inks employed are heatset, usually of about 40 volume percent
solvent. The solvent in high speed operations is generally a
selected petroleum fraction akin to kerosene and fuel oil, with a
boiling point of 200-370°C (400-700°F),13
Rotogravure - In gravure printing, the image area is engraved, or
"intaglio" relative to the surface of the image carrier, which is a
copper plated steel cylinder that is usually also chrome plated to
enhance wear resistance. The gravure cylinder rotates in an ink
trough or fountain. The ink is picked up in the engraved area, and
ink is scraped off the nonimage area with a steel "doctor blade".
The image is transferred directly to the web when it is pressed
against the cylinder by a rubber covered impression roll, and the
product is then dried. Rotary gravure (web fed) systems are known
as "rotogravure" presses.
Rotogravure can produce illustrations with excellent color
control, and it may be used on coated or uncoated paper, film, foil
and almost every other type of substrate. Its use is concentrated
in publications and advertising such as newspaper supplements,
magazines and mail order catalogues; folding cartons and other
flexible packaging materials; and specialty products such as wall
and floor coverings, decorated household paper products and vinyl
upholstery. Figure 4.9-3 illustrates one unit of a publication
rotogravure press. Multiple units are required for printing multiple
colors.
The inks used in rotogravure publication printing contain from
55 to 95 volume percent low boiling solvent (average is 75 volume
percent), and they must have low viscosities. Typical gravure
4/81 Evaporation Loss Sources 4.9-3
-------
r " '
J THERMAL |
INCINERATOR V
I
1"
GAS
I
I HEAT
I EXCHANGER |
I #1 I
ONLY WHEN
CATALYTIC
UNIT IS
USED HERE
FAN
HEATSETINK
SOLVENT AND THERMAL
DEGRADATION
PRODUCTS
I SUPPLY FAN
AIR AND SMOKE
WEB
COMBUSTION
PRODUCTS,
UNBURNED
ORGANICS,
O2 DEPLETED
AIR
FRESH AIR
PRINTED WEB
COOL WATER
AIR
Figure 4.9-2. Web letterpress publication printing line emission points.
4.9-4
EMISSION FACTORS
4/81
-------
solvents include alcohols, aliphatic naphthas, aromatic hydrocarbons,
esters, glycol ethers, ketones and nitroparaffins. Water base
inks are in regular production use in some packaging and specialty
applications, such as sugar bags.
Rotogravure is similar to letterpress printing in that the web
is printed on one side at a time and must be dried after application
of each color. Thus, for four color, two sided publication printing,
eight presses are employed, each including a pass over a steam drum
or through a hot air dryer at temperatures from ambient up to 120°C
(250°F) where nearly all of the solvent is removed. For further
information, see Section 4.9.2.
Flexography - In flexographic printing, as in letterpress, the image
area is above the surface of the plate. The distinction is that
flexography uses a rubber image carrier and alcohol base inks. The
process is usually web fed and is employed for medium or long
multicolor runs on a variety of substrates, including heavy paper,
fiberboard and metal and plastic foil. The major categories of the
flexography market are flexible packaging and laminates, multiwall
bags, milk cartons, gift wrap, folding cartons, corrugated paperboard
(which is sheet fed), paper cups and plates, labels, tapes and
envelopes. Almost all milk cartons and multiwall bags and half of
all flexible packaging are printed by this process.
Steam set inks, employed in the "water flexo" or "steam set
flexo" process, are low viscosity inks of a paste consistency that
are gelled by water or steam. Steam set inks are used for paper
bag printing, and they produce no significant emissions. Water
base inks, usually pigmented suspensions in water, are also available
for some flexographic operations, such as the printing of multiwall
bags.
Solvent base inks are used primarily in publication printing,
as shown in Figure 4.9-3. As with rotogravure, flexography publi-
cation printing uses very fluid inks of about 75 volume percent
organic solvent. The solvent, which must be rubber compatible, may
be alcohol, or alcohol mixed with an aliphatic hydrocarbon or
ester. Typical solvents also include glycols, ketones and ethers.
The inks dry by solvent absorption into the web and by evaporation,
usually in high velocity steam drum or hot air dryers, at temper-
atures below 120°C (250°F).3'13 As in letterpress publishing, the
web is printed on only one side at a time. The web passes over
chill rolls after drying.
Emissions and Controls - Significant emissions from printing
operations consist primarily of volatile organic solvents. Such
emissions vary with printing process, ink formulation and coverage,
press size and speed, and operating time. The type of paper (coated
or uncoated) has little effect on the quantity of emissions, although
low levels of organic emissions are derived from the paper stock
4/81 Evaporation Loss Sources 4.9-5
-------
TO ATM
OSPHERE
TRACES OF
WATER
AND
SOLVENT
1
f
t
HOT WATER
1
| ] 1
CONDENSERI i DECANTER
SOLVENT) I
..MIXTUREi |-
* iSTILLl
1 1 i ' " 1 1-
1 1 1 WARM i
1 ' 'WATER ' '
COOL WATER
STEAM PLUS
SOLVENT
VAPOR I |
i ADSORBER i
* (ACTIVE MODE)
. ADSORBER 1
\ J
r
STEAM [
L_
*~
SOLVENTS
»
*- WATER
COMBUSTION
PRODUCTS
t
1
1
STEAM BOILER |
Try1
GAS . n
WATER
SOLVENT LADEN AIR
WEB-
INK
|
INK
FOUNTAIN
*
PRESS
(ONE UNIT)
i
STEAM DRUM OR
HOT AIR DRYER
«^-
CHILL
ROLLS
PRINTED WEB
T I n ll\
AIR AIR UCAT r-nni i
HEAT
FROM STEAM,
HOT WATER,
OR HOT AIR
COOL WATER
Figure 4.9-3. Rotogravure and flexography printing line emission points (chill rolls not
used in rotogravure publication printing).^
4.9-6
EMISSION FACTORS
4/81
-------
1 O
during drying. High volume web fed presses such as those discussed
above are the principal sources of solvent vapors. Total annual
emissions from the industry in 1977 were estimated to be 380,000 Mg
(418,000 tons). Of this total, lithography emits 28 percent, letter-
press 18 percent, gravure 41 percent and flexography 13 percent.
Most of the solvent contained in the ink and used for dampening
and cleanup eventually finds its way into the atmosphere, but some
solvent remains with the printed product leaving the plant and is
released to the atmosphere later. Overall solvent emissions can be
computed from Equation 1 using a material balance concept, except
in cases where a direct flame dryer is used and some of the solvent
is thermally degraded.
The density of naphtha base solvent at 21°C (70°F) is
6.2 pounds per gallon.
E , = T (1)
total v '
where
E . = total solvent emissions including those from the
printed product, kg (Ib)
T = total solvent use including solvent contained in
ink as used, kg (Ib)
The solvent emissions from the dryer and other Printline
components can be computed from Equation 2. The remaining solvent
leaves the plant with the printed product and/or is degraded in the
dryer.
v - !§! (loo - P)
*" " 100 100
where
E = solvent emissions from Printline, kg (Ib)
I = ink use, liters (gallons)
d = solvent density, kg/liter (Ib/gallon)
S and P = factors from Table 4.9-1
Per Capita Emission Factors - Although major sources contribute
most of the emissions for graphic arts operations, considerable
emissions also originate from minor graphic arts applications,
including inhouse printing services in general industries. Small
sources within the graphic arts industry are numerous and difficult
to identify, since many applications are associated with nonprinting
4/81 Evaporation Loss Sources 4.9-7
-------
TABLE 4.9-1.
TYPICAL PARAMETERS FOR COMPUTING SOLVENT EMISSIONS
FROM PRINTING LINES a'b
Process
Solvent
Content of Ink
(Volume %) [S]
Solvent Remaining
in Product and
Destroyed in Dryer
(%) [P]°
Emission
Factor
Rating
Web Offset
Publication
Newspaper
Web Letterpress
Publication
Newspaper
40
5
40
0
40 (hot air dryer) B
60 (direct flame dryer)
100 B
40 B
(not applicable)
Rotogravure
Flexography
75
75
2-7
2-7
C
C
References 1 and 14.
DValues for S and P are typical. Specific values for S and P
^should be obtained from a source to estimate its emissions.
""For certain packaging products, amount of solvent retained is
regulated by FDA.
TABLE 4.9-2. PER CAPITA NONMETHANE VOC EMISSION
FACTORS FOR SMALL GRAPHIC ARTS APPLICATIONS
EMISSION FACTOR RATING: D
Units
Emission Factor
kg/year/capita
Ib/year/capita
g/day/capita
Ib/day/capita
0.4
0.8
1
0.003
Reference 15. All nonmethane VOC.
Assumes a 6 day operating week (313 days/yr).
industries. Table 4.9-2 presents per capita factors for estimating
emissions from small graphic arts operations. The factors are
entirely nonmethane VOC and should be used for emission estimates
over broad geographical areas.
Web Offset Lithography - Emission points on web offset lithography
publication printing lines include (1) the ink fountains, (2) the
4.9-8
EMISSION FACTORS
4/81
-------
dampening system, (3) the plate and blanket cylinders, (4) the
dryer, (5) the chill rolls and (6) the product (see Figure 4.9-1).
Alcohol is emitted from Points 2 and 3. Washup solvents are a
small source of emissions from Points 1 and 3. Drying (Point 4) is
the major source, because 40 to 60 percent of the ink solvent is
removed from the web during this process.
The quantity of web offset emissions may be estimated from
Equation 1, or from Equation 2 and the appropriate data from
Table 4.9-1.
Web Letterpress - Emission points on web letterpress publication
printing lines are: the press (includes the image carrier and
inking mechanism), the dryer, the chill rolls and the product (see
Figure 4.9-2).
Web letterpress publication printing produces significant
emissions, primarily from the ink solvent, about 60 percent of
which is lost in the drying process. Washup solvents are a small
source of emissions. The quantity of emissions can be computed as
described for web offset.
Letterpress publication printing uses a variety of papers and
inks that lead to emission control problems, but losses can be
reduced by a thermal or catalytic incinerator, either of which may
be coupled with a heat exchanger.
Rotogravure - Emissions from rotogravure printing occur at the ink
fountain, the press, the dryer and the chill rolls (see Figure 4.9-3).
The dryer is the major emission point, because most of the VOC in
the low boiling ink is removed during drying. The quantity of
emissions can be computed from Equation 1, or from Equation 2 and
the appropriate parameters from Table 4.9-1.
Vapor capture systems are necessary to minimize fugitive
solvent vapor loss around the ink fountain and at the chill rolls.
Fume incinerators and carbon adsorbers are the only devices that
have a high efficiency in controlling vapors from rotogravure
operations.
Solvent recovery by carbon adsorption systems has been quite
successful at a number of large publication rotogravure plants.
These presses use a single water immiscible solvent (toluene) or a
simple mixture that can be recovered in approximately the propor-
tions used in the ink. All new publication gravure plants are
being designed to include solvent recovery.
Some smaller rotogravure operations, such as those that print
and coat packaging materials, use complex solvent mixtures in which
many of the solvents are water soluble. Thermal incineration with
heat recovery is usually the most feasible control for such operations.
4/81 Evaporation Loss Sources 4.9-9
-------
TABLE 4.9-3. ESTIMATED CONTROL TECHNOLOGY EFFICIENCIES
FOR PRINTING LINES
Reduction in
Method Application Organic Emissions
Carbon adsorption Publication rotogravure
operations 75
b c
Incineration Web offset lithography 95,
Web letterpress 95
Packaging rotogravure
printing operations 65
Flexography printing
operations 60
Q
Waterborne inks Some packaging rotogravure
printing operations^ 65-75
Some flexography packaging
printing operations 60
ft
Reference 3. Overall emission reduction efficiency (capture
.efficiency multiplied by control device efficiency).
Direct flame (thermal) catalytic and pebble bed. Three or more
pebble beds in a system have a heat recovery efficiency of 85%.
Reference 12. Efficiency of volatile organic removal - does not
.consider capture efficiency.
Reference 13. Efficiency of volatile organic removal - does not
consider capture efficiency.
Solvent portion consists of 75 volume % water and 25 volume %
..organic solvent .
With less demanding quality requirements.
With adequate primary and secondary heat recovery, the amount of
fuel required to operate both the incinerator and the dryer system
can be reduced to less than that normally required to operate the
dryer alone.
In addition to thermal and catalytic incinerators, pebble bed
incinerators are also available. Pebble bed incinerators combine
the functions of a heat exchanger and a combustion device, and can
achieve a heat recovery efficiency of 85 percent.
VOC emissions can also be reduced by using low solvent inks.
Waterborne inks, in which the volatile portion contains up to
20 volume percent water soluble organic compounds, are used
extensively in rotogravure printing of multiwall bags, corrugated
paperboard and other packaging products, although water absorption
into the paper limits the amount of Waterborne ink that can be
printed on thin stock before the web is seriously weakened.
4.9-10 EMISSION FACTORS 4/81
-------
Flexography - Emission points on flexographic printing lines are
the ink fountain, the press, the dryer and the chill rolls (see
Figure 4.9-3). The dryer is the major emission point, and emissions
can be estimated from Equation 1, or from Equation 2 and the
appropriate parameters from Table 4.9-1.
Vapor capture systems are necessary to minimize fugitive
solvent vapor loss around the ink fountain and at the chill rolls.
Fume incinerators are the only devices proven highly efficient in
controlling vapors from flexographic operations. VOC emissions can
also be reduced by using waterborne inks, which are used extensively
in flexographic printing of packaging products.
Table 4.9-3 shows estimated control efficiencies for printing
operations.
References for Section 4.9
1. "Air Pollution Control Technology Applicable to 26 Sources of
Volatile Organic Compounds", Office of Air Quality Planning
and Standards, U.S. Environmental Protection Agency, Research
Triangle Park, NC, May 27, 1977. Unpublished.
2. Peter N. Formica, Controlled and Uncontrolled Emission Rates
and Applicable Limitations for Eighty Processes, EPA-340/1-78-004,
U.S. Environmental Protection Agency, Research Triangle Park,
NC, April 1978.
3. Edwin J. Vincent and William M. Vatavuk, Control of Volatile
Organic Emissions from Existing Stationary Sources, Volume VIII;
Graphic Arts - Rotogravure and Flexography, EPA-450/2-78-033,
U.S. Environmental Protection Agency, Research Triangle Park,
NC, December 1978.
4. Telephone communication with C.M. Higby, Cal/Ink, Berkeley, CA,
March 28, 1978.
5. T.W. Hughes, et al., Prioritization of Air Pollution from
Industrial Surface Coating Operations, EPA-650/2-75-019a, U.S.
Environmental Protection Agency, Research Triangle Park, NC,
February 1975.
6. Harvey F. George, "Gravure Industry's Environmental Program",
Environmental Aspects of Chemical Use in Printing Operations,
EPA-560/1-75-005, U.S. Environmental Protection Agency, Research
Triangle Park, NC, January 1976.
7. K.A. Bownes, "Material of Flexography", ibid.
8. Ben H. Carpenter and Garland R. Hilliard, "Overview of Printing
Processes and Chemicals Used", ibid.
4/81 Evaporation Loss Sources 4.9-11
-------
9. R.L. Harvin, "Recovery and Reuse of Organic Ink Solvents",
ibid.
10. Joseph L. Zborovsky, "Current Status of Web Heatset Emission
Control Technology", ibid.
11. R.R. Gadomski, et al., Evaluations of Emission and Control
Technologies in the Graphic Arts Industries, Phase I; Final
Report, APTD-0597, National Air Pollution Control Administration,
Cincinnati, OH, August 1970.
12. R.R. Gadomski, et al., Evaluations of Emissions and Control
Technologies in the Graphic Arts Industries, Phase II; Web
Offset and Metal Decorating Processess, APTD-1463, U.S.
Environmental Protection Agency, Research Triangle Park, NC,
May 1973.
13. Control Techniques for Volatile Organic Emissions from
Stationary Sources, EPA-450/2-78-022, U.S. Environmental
Protection Agency, Research Triangle Park, NC, May 1978.
14. Telephone communication with Edwin J. Vincent, Office of Air
Quality Planning and Standards, U.S. Environmental Protection
Agency, Research Triangle Park, NC, July 1979.
15. W.H. Lamason, "Technical Discussion of Per Capita Emission
Factors for Several Area Sources of Volatile Organic Compounds",
Office of Air Quality Planning and Standards, U.S. Environmental
Protection Agency, Research Triangle Park, NC, March 15, 1981.
Unpublished.
4.9-12 EMISSION FACTORS 4/81
-------
4.9.2 PUBLICATION GRAVURE PRINTING
1 2
Process Description ' - Publication gravure printing is the printing
by the rotogravure process of a variety of paper products such as
magazines, catalogs, newspaper supplements and preprinted inserts,
and advertisements. Publication printing is the largest sector
involved in gravure printing, representing over 37 percent of the
total gravure product sales value in a 1976 study.
The rotogravure press is designed to operate as a continuous
printing facility, and normal operation may be either continuous or
nearly so. Normal press operation experiences numerous shutdowns
caused by web breaks or mechanical problems. Each rotogravure
press generally consists of eight to sixteen individual printing
units, with an eight unit press the most common. In publication
printing, only four colors of ink are used, yellow, red, blue and
black. Each unit prints one ink color on one side of the web, and
colors other than these four are produced by printing one color
over another to yield the desired product.
In the rotogravure printing process, a web or substrate from a
continuous roll is passed over the image surface of a revolving
gravure cylinder. For publication printing, only paper webs are
used. The printing images are formed by many tiny recesses or
cells etched or engraved into the surface of the gravure cylinder.
The cylinder is about one fourth submerged in a fountain of low
viscosity mixed ink. Raw ink is solvent diluted at the press and
is sometimes mixed with related coatings, usually referred to as
extenders or varnishes. The ink, as applied, is a mixture of
pigments, binders, varnish and solvent. The mixed ink is picked up
by the cells on the revolving cylinder surface and is continuously
applied to the paper web. After impression is made, the web travels
through an enclosed heated air dryer to evaporate the volatile
solvent. The web is then guided along a series of rollers to the
next printing unit. Figure 4.9.2-1 illustrates this printing
process by an end (or side) view of a single printing unit.
At present, only solventborne inks are used on a large scale
for publication printing. Waterborne inks are still in research
and development stages, but some are now being used in a few limited
cases. Pigments, binders and varnishes are the nonvolatile solid
components of the mixed ink. For publication printing, only ali-
phatic and aromatic organic liquids are used as solvents. Presently,
two basic types of solvents, toluene and a toluene-xylene-naphtha
mixture, are used. The naphtha base solvent is the more common.
Benzene is present in both solvent types as an impurity, in concen-
trations up to about 0.3 volume percent. Raw inks, as purchased,
have 40 to 60 volume percent solvent, and the related coatings
typically contain about 60 to 80 volume percent solvent. The
applied mixed ink consists of 75 to 80 volume percent solvent,
required to achieve the proper fluidity for rotogravure printing.
4/81 Evaporative Loss Sources 4.9.2-1
-------
1 3-4
Emissions and Controls ' - Volatile organic compound (VOC) vapors
are the only significant air pollutant emissions from publication
rotogravure printing. Emissions from the printing presses depend
on the total amount of solvent used. The sources of these VOC
emissions are the solvent components in the raw inks, related
coatings used at the printing presses, and solvent added for dilu-
tion and press cleaning. These solvent organics are photochemically
reactive. VOC emissions from both controlled and uncontrolled publi-
cation rotogravure facilities in 1977 were about 57,000 megagrams
(63,000 tons), 15 percent of the total from the graphic arts industry.
Emissions from ink and solvent storage and transfer facilities are
not considered here.
Table 4.9-1 presents emission factors for publication printing
on rotogravure presses with and without control equipment. The
potential amount of VOC emissions from the press is equal to the
total amount of solvent consumed in the printing process (see
Footnote f). For uncontrolled presses, emissions occur from the
dryer exhaust vents, printing fugitive vapors, and evaporation of
solvent retained in the printed product. About 75 to 90 percent
of the VOC emissions occur from the dryer exhausts, depending on
press operating speed, press shutdown frequency, ink and solvent
composition, product printed, and dryer designs and efficiencies.
The amount of solvent retained by the various rotogravure printed
products is three to four percent of the total solvent in the ink
used. The retained solvent eventually evaporates after the printed
product leaves the press.
There are numerous points around the printing press from
which fugitive emissions occur. Most of the fugitive vapors result
from solvent evaporation in the ink fountain, exposed parts of the
gravure cylinder, the paper path at the dryer inlet, and from the
paper web after exiting the dryers between printing units. The
quantity of fugitive vapors depends on the solvent volatility, the
temperature of the ink and solvent in the ink fountain, the amount
of exposed area around the press, dryer designs and efficiencies,
and the frequency of press shutdowns.
The complete air pollution control system for a modern
publication rotogravure printing facility consists of two sections,
the solvent vapor capture system and the emission control device.
The capture system collects VOC vapors emitted from the presses and
directs them to a control device where they are either recovered or
destroyed. Low-VOC waterborne ink systems to replace a significant
amount of solventborne inks have not been developed as an emission
reduction alternative.
Capture Systems - Presently, only the concentrated dryer
exhausts are captured at most facilities. The dryer exhausts
contain the majority of the VOC vapors emitted. The capture
efficiency of dryers is limited by their operating temperatures and
4.9.2-2 EMISSION FACTORS 4/81
-------
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4.9.2-3
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4.9.2-4
EMISSION FACTORS
4/81
-------
other factors that affect the release of the solvent vapors from
the print and web to the dryer air. Excessively high temperatures
impair product quality. The capture efficiency of older design
dryer exhaust systems is about 84 percent, and modern dryer systems
can achieve 85 to 89 percent capture. For a typical press, this
type capture system consists of ductwork from each printing unit's
dryer exhaust joined in a large header. One or more large fans are
employed to pull the solvent laden air from the dryers and to
direct it to the control device.
A few facilities have increased capture efficiency by gathering
fugitive solvent vapors along with the dryer exhausts. Fugitive
vapors can be captured by a hood above the press, by a partial
enclosure around the press, by a system of multiple spot pickup
vents, by multiple floor sweep vents, by total pressroom ventila-
tion capture, or by various combinations of these. The design of
any fugitive vapor capture system needs to be versatile enough to
allow safe and adequate access to the press in press shutdowns.
The efficiencies of these combined dryer exhaust and fugitive
capture systems can be as high as 93 to 97 percent at times, but
the demonstrated achievable long term average when printing several
types of products is only about 90 percent.
Control Devices - Various control devices and techniques may
be employed to control captured VOC vapors from rotogravure presses.
All such controls are of two categories, solvent recovery and
solvent destruction.
Solvent recovery is the only present technique to control VOC
emissions from publication presses. Fixed bed carbon adsorption by
multiple vessels operating in parallel configuration, regenerated
by steaming, represents the most used control device. A new
adsorption technique using a fluidized bed of carbon might be
employed in the future. The recovered solvent can be directly
recycled to the presses.
There are three types of solvent destruction devices used to
control VOC emissions, conventional thermal oxidation, catalytic
oxidation and regenerative thermal combustion. These control
devices are employed for other rotogravure printing. At present,
none are being used on publication rotogravure presses.
The efficiency of both solvent destruction and solvent recovery
control devices can be as high as 99 percent. However, the
achievable long term average efficiency for pxiblication printing is
about 95 percent. Older carbon adsorber systems were designed to
perform at about 90 percent efficiency. Control device emission
factors presented in Table 4.9-1 represent the residual vapor
content of the captured solvent laden air vented after treatment.
Overall Control - The overall emissions reduction efficiency
for VOC control systems is equal to the capture efficiency times
4/81 Evaporative Loss Sources 4.9.2-5
-------
the control device efficiency. Emission factors for two control
levels are presented in Table 4.9.2-1. The 75 percent control level
represents 84 percent capture with a 90 percent efficient control
device. (This is the EPA control techniques guideline recommenda-
tion for State regulations on old existing presses.) The 85 percent
control level represents 90 percent capture with a 95 percent effi-
cient control device. This corresponds to application of best
demonstrated control technology for new publication presses.
References for Section 4.9.2
1. Publication Rotogravure Printing - Background Information for
Proposed Standards, EPA-450/3-80-03la, U.S. Environmental
Protection Agency, Research Triangle Park, NC, October 1980.
2. Publication Rotogravure Printing - Background Information for
Promulgated Standards, EPA-450/3-80-031b, U.S. Environmental
Protection Agency, Research Triangle Park, NC. Expected
November 1981.
3. Control of Volatile Organic Emissions from Existing Stationary
Sources, Volume VIII; Graphic Arts - Rotogravure and Flexography,
EPA-450/2-78-033, U.S. Environmental Protection Agency, Research
Triangle Park, NC, December 1978.
4. Standards of Performance for New Stationary Sources: Graphic
Arts - Publication Rotogravure Printing, 45 FR 71538, October 28,
1980.
5. Written communication from Texas Color Printers, Inc., Dallas,
TX, to Radian Corp., Durham, NC, July 3, 1979.
6. Written communication from Meredith/Burda, Lynchburg, VA, to
Edwin Vincent, Office of Air Quality Planning and Standards,
U.S. Environmental Protection Agency, Research Triangle Park,
NC, July 6, 1979.
7. W.R. Feairheller, Graphic Arts Emission Test Report, Meredith/
Burda, Lynchburg, VA, EPA Contract No. 68-02-2818, Monsanto
Research Corp., Dayton, OH, April 1979.
8. W.R. Feairheller, Graphic Arts Emission Test Report, Texas
Color Printers, Dallas, TX, EPA Contract No. 68-02-2818,
Monsanto Research Corp., Dayton, OH, October 1979.
4.9.2-6 EMISSION FACTORS 4/81
-------
4.10 COMMERCIAL/CONSUMER SOLVENT USE
4.10.1 General1'2
Commercial and consumer use of various products containing
volatile organic compounds (VOC) contributes to formation of tropo-
spheric ozone. The organics in these products may be released
through immediate evaporation of an aerosol spray, evaporation
after application, and direct release in the gaseous phase. Organics
may act either as a carrier for the active product ingredients or
as active ingredients themselves. Commercial and consumer products
which release volatile organic compounds include aerosols, household
products, toiletries, rubbing compounds, windshield washing fluids,
polishes and waxes, nonindustrial adhesives, space deodorants, moth
control applications, and laundry detergents and treatments.
4.10.2 Emissions
Major volatile organic constituents of these products which
are released to the atmosphere include special naphthas, alcohols
and various chloro- and fluorocarbons. Although methane is not
included in these products, 31 percent of the volatile organic
compounds released in the use of these products is considered
nonreactive under EPA policy. '
National emissions and per capita emission factors for commercial
and consumer solvent use are presented in Table 4.10-1. Per capita
emission factors can be applied to area source inventories by
multiplying the factors by inventory area population. Note that
adjustment to exclude the nonreactive emissions fraction cited
above should be applied to total emissions or to the composite
factor. Care is advised in making adjustments, in that substitution
of compounds within the commercial/consumer products market may
alter the nonreactive fraction of compounds.
References for Section 4.10
1. W.H. Lamason, "Technical Discussion of Per Capita Emission
Factors for Several Area Sources of Volatile Organic Compounds",
Monitoring and Data Analysis Division, U.S. Environmental
Protection Agency, Research Triangle Park, NC, March 15, 1981.
Unpublished.
2. End Use of Solvents Containing Volatile Organic Compounds,
EPA-450/3-79-032, U.S. Environmental Protection Agency,
Research Triangle Park, NC, May 1979.
3. Final Emission Inventory Requirements for 1982 Ozone State
Implementation Plans, EPA-450/4-80-016, U.S. Environmental
Protection Agency, Research Triangle Park, NC, December 1980.
4/81 Evaporation Loss Source 4.10-1
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EMISSION FACTORS
4/81
-------
4. Procedures for the Preparation of Emission Inventories for
Volatile Organic Compounds, Volume I, Second Edition, EPA-4i>0/
2-77-028, U.S. Environmental Protection Agency, Research
Triangle Park, NC, September 1980.
4/81 Evaporation Loss Source- 4.10-3
-------
-------
5.17 SULFURIC ACID
5.17.1 General
All sulfuric acid is made by either the lead chamber process
or the contact process. Because the contact process accounts for
more than 97 percent of the total sulfuric acid production in the
United States, it is the only process discussed in this Section.
Contact plants are generally classified according to the raw materials
charged to them - (1) elemental sulfur burning, (2) spent acid and
hydrogen sulfide burning, and (3) sulfide ores and smelter gas
burning, The contributions from these plants to the total acid
production are 68, 18.5 and 13.5 percent respectively.
All contact processes incorporate three basic operations, each
of which corresponds to a distinct chemical reaction. First, the
sulfur in the feedstock is burned to sulfur dioxide:
S + 02 ^- S02
Sulfur Oxygen Sulfur (1)
dioxide
Then, the sulfur dioxide is catalytically oxidized to sulfur trioxide:
2S02 + 02 ->> 2S03
Sulfur Oxygen Sulfur (2)
dioxide trioxide
Finally, the sulfur trioxide is absorbed in a strong aqueous solution
of sulfuric acid:
S03 + H20 ^ H2S04
Sulfur Water Sulfuric (3)
trioxide acid
1 2
Elemental Sulfur Burning Plants ' - Elemental sulfur, such as
Frasch process sulfur from oil refineries, is melted, settled or
filtered to remove ash and is fed into a combustion chamber. The
sulfur is burned in clean air that has been dried by scrubbing with
93 - 99 percent sulfuric acid. The gases from the combustion chamber
cool and then enter the solid catalyst (vanadium pentoxide) con-
verter. Usually, 95 - 98 percent of the sulfur dioxide from the
combustion chamber is converted to sulfur trioxide, with an accompany-
ing large evolution of heat. After being cooled, the converter exit
gas enters an absorption tower, where the sulfur trioxide is absorbed
with 98 - 99 percent sulfuric acid. The sulfur trioxide combines
with the water in the acid and forms more sulfuric acid.
If oleum, a solution of uncombined 863 in H2S04, is produced,
SO^ from the converter is first passed to an oleum tower that is
fed with 98 percent acid from the absorption system. The gases
4/31 Chemical Process Industry 5.17-1
-------
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5.17-2
EMISSION FACTORS
4/81
-------
-AIR'
-SPENT ACID
SULFUR
FUEL OIL
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STEAM
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Figure 5.17-2. Basic flow diagram of contact process sulfuric acid plant burning spent acid.
4/81
Chemical Process Industry
5.17-3
-------
from the oleum tower are then pumped to the absorption column where
the residual sulfur trioxide is removed.
A schematic diagram of a contact process sulfuric acid plant
that burns elemental sulfur is shown in Figure 5.17-1.
1 2
Spent Acid and Hydrogen Sulfide Burning Plants ' - Two types of
plants are used to process this type of sulfuric acid. In one, the
sulfur dioxide and other combustion products from the combustion of
spent acid and/or hydrogen sulfide with undried atmospheric air are
passed through gas cleaning and mist removal equipment, The gas
stream next passes through a drying tower. A blower draws the gas
from the drying tower and discharges the sulfur dioxide gas to the
sulfur trioxide converter. A schematic diagram of a contact process
sulfuric acid plant that burns spent acid is shown in Figure 5.17-2.
In a "wet gas plant", the wet gases from the combustion chamber
are charged directly to the converter with no intermediate treatment.
The gas from the converter flows to the absorber, through which
93 - 98 percent sulfuric acid is circulating.
Sulfide Ores and Smelter Gas Plants - The configuration of this
type of plant is essentially the same as that of a spent acid plant
(Figure 5.17-2), with the primary exception that a roaster is used
in place of the combustion furnace.
The feed used in these plants is smelter gas, available from
such equipment as copper converters, reverberatory furnaces,
roasters and flash smelters. The sulfur dioxide in the gas is con-
taminated with dust, acid mist and gaseous impurities. To remove
the impurities, the gases must be cooled and passed through purifi-
cation equipment consisting of cyclone dust collectors, electrostatic
dust and mist precipitators, and scrubbing and gas cooling towers.
After the gases are cleaned and the excess water vapor is removed,
they are scrubbed with 98 percent acid in a drying tower. Beginning
with the drying tower stage, these plants are nearly identical to
the elemental sulfur plants shown in Figure 5.17-1.
5.17.2 Emissions and Controls
1-3
Sulfur Dioxide - Nearly all sulfur dioxide emissions from
sulfuric acid plants are found in the exit gases. Extensive testing
has shown that the mass of these SO2 emissions is an inverse func-
tion of the sulfur conversion efficiency (SC>2 oxidized to SO-}).
This conversion is always incomplete, and is affected by the number
of stages in the catalytic converter, the amount of catalyst used,
temperature and pressure, and the concentrations of the reactants
(sulfur dioxide and oxygen). For example, if the inlet SC>2 concen-
tration to the converter were 8 percent by volume (a representative
value), and the conversion temperature were 473°C (883°F), the con-
version efficiency would be 96 percent. At this conversion, the
5.17-4 EMISSION FACTORS 4/81
-------
uncontrolled emission factor for SC>2 would be 27.5 kg/Mg (55 pounds
per ton) of 100 percent sulfuric acid produced, as shown in
Table 5.17-1. For purposes of comparison, note that the Environ-
mental Protection Agency performance standard for new and modified
plants is 2 kg/Mg (4 pounds per ton) of 100 percent acid produced,
maximum 2 hour average. As Table 5.17-1 and Figure 5.17-3 indicate,
achieving this standard requires a conversion efficiency of 99.7
percent in an uncontrolled plant or the equivalent 862 collec-
tion mechanism in a controlled facility. Most single absorption
plants have SO conversion efficiencies ranging from 95 - 98 percent.
In addition to exit gases, small quantities of sulfur oxides
are emitted from storage tank vents and tank car and tank truck vents
during loading operations, from sulfuric acid concentrators, and
through leaks in process equipment. Few data are available on the
quantity of emissions from these sources.
Of the many chemical and physical means for removing SO2 from
gas streams, only the dual absorption and the sodium sulfite/bisul-
fite scrubbing processes have been found to increase acid production
without yielding unwanted byproducts.
TABLE 5.17-1. EMISSION FACTORS FOR SULFURIC
ACID PLANTS3
EMISSION FACTOR RATING: A
S02 Emissions
Conversion of S02
to S03 (%)
93
94
95
96
97
98
99
99.5
99.7
100
kg/Mg of 100%
H2S04
48.0
41.0
35.0
27.5
20.0
13.0
7.0
3.5
2.0
0.0
Ib/ton of 100%
H2S04
96
82
70
55
40
26
14
7
4
0
a
.Reference 1.
This linear interpolation formula can be used for calculating
emission factors for conversion efficiencies between 93 and 100%:
emission factor = 13.65 (% conversion efficiency) + 1365.
4/81 Chemical Process Industry 5.17-5
-------
99.92
10,000
SULFUR CONVERSION, % feedstock sulfur
99.7 99.0
98.0
97.0 96.0 95.0
1.5 2 2.5 3 4 5 6 7 8 9 10 15 20 25 30 40 50 60708090100
S02EMISSIONS, Ib/ton of 100% H2S04 produced
Figure 5.17-3. Sulfuric acid plant feedstock sulfur conversion versus volumetric and
mass SC>2 emissions at various inlet SC>2 concentrations by volume.
5.17-6
EMISSION FACTORS
4/81
-------
In the dual absorption process, the 863 gas formed in the
primary converter stages is sent to a primary absorption tower where
most of the 863 is removed to form 112804. The remaining unconverted
sulfur dioxide is forwarded to the final stages in the converter to
remove much of the remaining 802 ^Y oxidation to 803, from whence
it is sent to the secondary absorber for final sulfur trioxide
removal. The result is the conversion of a much higher fraction of
S02 to 803 (a conversion of 99.7 percent or higher, on the average,
which meets the performance standard). Furthermore, dual absorption
permits higher converter inlet sulfur dioxide concentrations than
are used in single absorption plants, because the secondary conver-
sion stages effectively remove any residual sulfur dioxide from the
primary absorber.
Where dual absorption reduces sulfur dioxide emissions by
increasing the overall conversion efficiency, the sodium sulfite/
bisulfite scrubbing process removes sulfur dioxide directly from
the absorber exit gases. In one version of this process, the sul-
fer dioxide in the waste gas is absorbed in a sodium sulfite solution,
is separated, and is recycled to the plant. Test results from a
680 Mg (750 ton per day) plant equipped with a sulfite scrubbing
system indicated an average SO emission factor of 1.35 kg/Mg
(2.7 pounds per ton) of 100 percent acid.
1-3
Acid Mist - Nearly all the acid mist emitted from sulfuric acid
manufacturing can be traced to the absorber exit gases. Acid mist
is created when sulfur trioxide combines with water vapor at a
temperature below the dew point of sulfur trioxide. Once formed
within the process system, this mist is so stable that only a small
quantity can be removed in the absorber.
In general, the quantity and particle size distribution of
acid mist are dependent on the type of sulfur feedstock used, the
strength of acid produced, and the conditions in the absorber.
Because it contains virtually no water vapor, bright elemental
sulfur produces little acid mist when burned. However, the hydro-
carbon impurities in other feedstocks - dark sulfur, spent acid
and hydrogen sulfide - oxidize to water vapor during combustion.
The water vapor, in turn, combines with sulfur trioxide as the gas
cools in the system.
The strength of acid produced - whether oleum or 99 percent
sulfuric acid - also affects mist emissions. Oleum plants produce
greater quantities of finer more stable mist. For example, uncon-
trolled mist emissions from oleum plants burning spent acid range
from 0.5 to 5.0 kg/Mg (1.0 to 10.0 pounds per ton), while those
from 98 percent acid plants burning elemental sulfur range from
0.2 to 2.0 kg/Mg (0.4 to 4.0 pounds per ton). Furthermore,
85 - 95 weight percent of the mist particles from oleum plants are
less than 2 microns in diameter, compared with only 30 weight
percent that are less than 2 microns in diameter from 98 percent
acid plants.
4/81 Chemical Process Industry 5.17-7
-------
The operating temperature of the absorption column directly
affects sulfur trioxide absorption and, accordingly, the quality of
acid mist formed after exit gases leave the stack. The optimum
absorber operating temperature depends on the strength of the acid
produced, throughput rates, inlet sulfur trioxide concentrations,
and other variables peculiar to each individual plant. Finally,
it should be emphasized that the percentage conversion of sulfur
trioxide has no direct effect on acid mist emissions. In
Table 5.17-2, uncontrolled acid mist emissions are presented for
various sulfuric acid plants.
TABLE 5.17-2. ACID MIST EMISSION FACTORS FOR SULFURIC
ACID PLANTS WITHOUT CONTROLS3
EMISSIONS FACTOR RATING: B
b
Emissions
Oleum produced,
Raw material % total output kg/Mg acid Ib/ton acid
Recovered sulfur
Bright virgin sulfur
Dark virgin sulfur
Sulfide ores
Spent acid
0
33
0
0
to
0
to
to
to
43
100
25
77
0.
0.
0.
1.
175
0.
16
6 -
1 -
_
85
3
1
0
3.
.7
.2
.4
15
0.
0.
1.
2.
35
32
2
2
- 0.8
1.7
- 6.3
- 7.4
- 2.4
, Reference 1.
Emissions are proportional to the percentage of oleum in the total
product. Use low end of ranges for low oleum percentage and high
end of ranges for high oleum percentage.
Two basic types of devices, electrostatic precipitators and
fiber mist eliminators, effectively reduce the acid mist concentra-
tion from contact plants to less than the EPA New Source Performance
Standard, which is 0.075 kg/Mg (0.15 pound per ton) of acid. Pre-
cipitators, if properly maintained, are effective in collecting the
mist particles at efficiencies up to 99 percent (see Table 5.17-3).
The three most commonly used fiber mist eliminators are the
vertical tube, vertical panel, and horizontal dual pad types. They
differ from one another in the arrangement of the fiber elements,
which are composed of either chemically resistant glass or fluoro-
carbon, and in the means employed to collect the trapped liquid.
The operating characteristics of these three types are compared with
electrostatic precipitators in Table 5.17-3.
5.17-8 EMISSION FACTORS 4/81
-------
TABLE 5.17-3. EMISSION COMPARISON AND COLLECTION EFFICIENCY OF
TYPICAL ELECTROSTATIC PRECIPITATOR AND FIBER MIST ELIMINATORS3
Control device
Particle size
collection
efficiency, %
Acid mist emissions
98% acid plants Oleum plants
>3 (am <3|_tm kg/Mg Ib/ton kg/Mg Ib/ton
Electrostatic
precipitator
Fiber mist
eliminator
99
100
0.05
0.10
0.06
.Reference 2.
Based on manufacturers' generally expected results.
SO concentration in gas converter.
References for Section 5.17
0.12
Tabular
Panel
Dual pad
100
100
100
95-99
90-98
93-99
0.01
0.05
0.055
0.02
0.10
0.11
0.01
0.05
0.055
0.02
0.10
0.11
Calculated for
1. Atmospheric Emissions from Sulfuric Acid Manufacturing Processes,
999-AP-13, U.S. Department of Health, Education and Welfare,
Washington, DC, 1966.
2. Unpublished report on control of air pollution from sulfuric
acid plants, U.S. Environmental Protection Agency, Research
Triangle Park, NC, August 1971.
3. Standards of Performance for New Stationary Sources, 36 FR 24875,
December 23, 1971.
4. M. Drabkin and Kathryn J. Brooks, A Review of Standards of
Performance for New Stationary Sources - Sulfuric Acid Plants,
EPA Contract No. 68-02-2526, Mitre Corporation, McLean, VA,
June 1978.
5. Final Guideline Document; Control of Sulfuric Acid Mist
Emissions from Existing Sulfuric Acid Production Units,
EPA 450/2-77-019, U.S. Environmental Protection Agency,
Research Triangle Park, NC, September 1977.
4/81
Chemical Process Industry
5.17-9
-------
-------
6.5 FERMENTATION
Process Description1
For the purpose of this report only the fermentation industries associated with food will be considered. This
includes the production of beer, whiskey, and wine.
The manufacturing process for each of these is similar. The foui main brewing production stages and their
respective sub-stages are: (1) brewhouse operations, which include (a) malting of the barley, (b) addition of
adjuncts (corn, grits, and rice) to barley mash, (c) conversion of starch in barley and adjuncts to maltose sugar b\
enzymatic processes, (d) separation of wort from grain by straining, and (e) hopping and boiling of the wort; (2)
fermentation, which includes (a) cooling of the wort, (b) additional yeast cultures, (c) fermentation for 7 to 10
days, (d) removal of settled yeast, and (e) filtration and carbonation; (3) aging, which lasts from 1 to 2 months
under refrigeration; and (4) packaging, which includes (a) bottlmg-pasteunzation, and (b) racking draft beer.
The major differences between beer production and whiskey production are the purification and distillation
necessary to obtain distilled liquors and the longer period of aging. The primary difference between wine making
and beer making is that grapes are used as the initial raw material in wine rather than grains.
2/72 Food and Agricultural Industry 6.5-1
-------
Table 6.5-1. EMISSION FACTORS FOR FERMENTATION PROCESSES
EMISSION FACTOR RATING: E
Type of product
Particulates
Ib/ton
kg/MT
Hydrocarbons
Ib/ton
kg/MT
Beer
Grain handling3
Drying spent grains, etc.3
Whiskey
Gram handling3
Drying spent grains, etc.3
Aging
Wine
See Subsection 6.5.1
1.5
2.5
NA I NA
10° 0.024d
See Subsection 6.5.2
aBased on section on grain processing
bNo emission factor available, but emiss ons do occur
GPounds per year per barrel of whiskey stored
Kilograms per year per liter of whiskey stored.
eNo significant emissions.
References for Section 6.5
i. Air Pollutan' Emission Factors. Final Report Resources Research, Inc. Reston, Va. Prepared for National
Air Pollution Control Administration. Durham. N C.. under Contract Number CPA-22-69-119. April 1970.
2. Shreve. R.N. Chemical Process Industries, 3rd Ed. New York, McGraw-Hill Book Company. 1967. p.
591-608.
6.5-2
EMISSION FACTORS
2/72
-------
6.5.1. BEER MAKING
1-3
6.5.1.1 General
Beer is a beverage of low alcoholic content (2-7 percent)
made by the fermentation of malted starchy cereal grains. Barley
is the principal grain used. The production of beer is carried out
in four major stages, brewhouse operations, fermentation, aging and
packaging. These processes are shown in Figure 6.5.1-1.
Brewhouse operations include malting of the barley, addition
of adjuncts to the barley mash, conversion of the starch in the
barley and adjuncts to maltose sugar, separation of wort from the
grain, and hopping and boiling of the wort.
In malting, barley is continuously moistened to cause it to
germinate. With germination, enzymes are formed which break down
starches and proteins to less complex water soluble compounds. The
malted barley is dried to arrest the enzyme formation and is ground
in a malt or roll mill. Adjuncts, consisting of other grains
(ground and unmalted), sugars and syrups, are added to the ground
malted barley and, with a suitable amount of water, are charged to
the mash tun (tank-like vessel). Conversion of the complex
carbohydrates (starch and sugars) and proteins to simpler water
soluble fermentable compounds by means of enzyme action takes
place in the mash tun, a process called mashing. The mash is sent
to a filter press or straining tub (lauter tun) where the wort
(unfermented beer) is separated from the spent grain solids. Hops
are added to the wort in a brew kettle, where the wort is boiled
one and a half to three hours to extract essential substances from
the hops, to concentrate the wort, and to destroy the malt enzymes.
The wort is strained to remove hops, and sludge is removed by a
filter or centrifuge.
Wort is cooled to 10°C (50°F) or lower. During cooling, it
absorbs air necessary to start fermentation. The yeast is added
and mixed with the wort in line to the fermentation starter tanks.
Fermentation, the conversion of the simple sugars in the wort to
ethanol and carbon dioxide, is completed in a closed fermenter.
The carbon dioxide gas released by the fermentation is collected
and later used for carbonating the beer. Cooling to maintain
proper fermentation temperature is required because the reaction is
exothermic.
After fermentation is complete, beer is stored to age for
several weeks at 0°C (32°F) in large closed tanks. It is recar-
bonated, pumped through a pulp filter, pasteurized at 60°C (140°F)
to make it biologically stable, and packaged in bottles and cans.
Beer put in kegs for draft sale is not pasteurized.
4/81 Food and Agricultural Industry 6.5.1-1
-------
(Pasteurizer
V
/ Packager /
Figure 6.5.1-1. Flow diagram of a beer making process.
6.5.1.2 Emissions and Controls
2-7
The major emissions from beer making and their sources are
particulates and volatile organics, mainly ethanol, from spent
grain drying, and particulates from grain handling. Volatile
organics (VOC) from fermentation are negligible, and they are
fugitive because the fermenters are closed to provide for collecting
carbon dioxide. Other brewery processes are minor sources of
volatile organics, ethanol and related compounds, such as boiling
6.5.1-2
EMISSION FACTORS
4/81
-------
wort in the brew kettle and malt drying. An estimate of these
emissions is not available.
Fugitive particulate emissions from grain handling and milling
at breweries are reduced by operating in well ventilated, low
pressure conditions. At grain handling and milling operations,
fabric filters are most often used for dust collection. Organics
and organic particulate matter from spent grain drying can be
controlled by mixing the dryer exhaust with the combustion air of a
boiler. A centrifugal fan wet scrubber is the most commonly used
control.
TABLE 6.5.1-1. EMISSION FACTORS FOR BEER BREWING3
EMISSION FACTOR RATING: D
Source
Grain handling
Brew kettle
Spent grain drying
Cooling units
Fermentation
Particulate
1.5 (3)b
2.5 (5)b
Volatile Organic Compounds
c
NA
1.31 (2.63)d
NAC
e
Neg
a 6
Expressed in terms of kg/10 g (Ib/ton) of grain handled. Blanks
.indicate no emissions.
Reference 6.
Factors not available, but negligible amounts of ethanol emissions
,are suspected.
Reference 4. Mostly ethanol.
eNegligible amounts of ethanol, ethyl acetate, isopropyl alcohol,
n-propyl alcohol, isoamyl alcohol, and isoamyl acetate emissions
are suspected.
References for Section 6.5.1
1. H.E. H^yrup, "Beer and Brewing", Kirk-Othmer Encyclopedia of
Chemical Technology, Volume 3, John Wiley and Sons, Inc.,
New York, 1964, pp. 297-338.
2. R. Norris Shreve, Chemical Process Industries, 3rd Ed.,
McGraw-Hill Book Company, New York, 1967, pp. 603-605.
3. E.G. Cavanaugh, et al., Hydrocarbon Pollutants from Stationary
Sources, EPA-600/7-77-110, U.S. Environmental Protection Agency,
Research Triangle Park, NC, September 1977.
4/81 Food and Agricultural Industry 6.5.1-3
-------
4. H.W. Bucon, et al., Volatile Organic Compound (VOC) Species
Data Manual, Second Edition, EPA-450/4-80-015, U.S. Environmental
Protection Agency, Research Triangle Park, NC, December 1978.
5. Melvin W. First, et al., "Control of Odors and Aerosols from
Spent Grain Dryers", Journal of the Air Pollution Control
Association, 24_(7): 653-659, July 1974.
6. AEROS Manual Series, Volume V: AEROS Manual of Codes,
EPA-450/2-76-005, U.S. Environmental Protection Agency, Research
Triangle Park, NC, April 1976.
7. Peter N. Formica, Controlled and Uncontrolled Emission Rates
and Applicable Limitations for Eighty Processes, EPA-340/1-78-004,
U.S. Environmental Protection Agency, Research Triangle Park,
NC, April 1978.
6.5.1-4 EMISSION FACTORS 4/81
-------
6.18 AMMONIUM SULFATE MANUFACTURE
6.18.1 General1
Ammonium sulfate, [Nh^^SO^ is commonly used as a fertilizer.
About 90 percent of ammonium sulfate is produced by three types of
facilities, caprolactam byproduct, synthetic, and coke oven byproduct
plants. The remainder is produced as a byproduct of nickel manu-
facture from ore concentrates, methyl methacrylate manufacture, and
ammonia scrubbing of tail gas at sulfuric acid plants.
During the manufacture of caprolactam, [Ct^^COHN, ammonium
sulfate is produced from the oximation process stream and the
rearrangement reaction stream. Synthetic ammonium sulfate is
produced by the direct combination of ammonia and sulfuric acid in
a reactor. Coke oven byproduct ammonium sulfate is produced by
reacting ammonia recovered from coke oven offgas with sulfuric
acid. Figure 6.18-1 is a process flow diagram for each of the
three primary commercial processes.
After formation of the ammonium sulfate solution, operations
of each process are similar. Ammonium sulfate crystals are formed
by continuously circulating an ammonium sulfate liquor through an
evaporator to thicken the solution. Ammonium sulfate crystals are
separated from the liquor in the centrifuge. The saturated liquor
is returned to the dilute ammonium sulfate brine of the evaporator.
The crystals, with about 1 to 2.5 percent moisture by weight after
the centrifuge, are fed to either a fluidized bed or rotary drum
dryer. Fluidized bed dryers are continuously steam heated, and
rotary dryers are either directly fired with oil or natural gas, or
they use steam heated air. At coke oven byproduct plants, rotary
drum dryers may be used in place of a centrifuge and dryer. On the
filter of these dryers, a crystal layer is deposited which is
removed from the drum by a scraper or a knife.
The volume of ammonium sulfate in the dryer exhaust gas varies
according to production process and dryer type. A gas flow rate of
620 scm/Mg of product (20,000 scf/ton) is considered representative
of a direct fired rotary drum dryer. A gas flow of 2,500 scm/Mg of
product (80,000 scf/ton) is considered representative of a steam
heated fluidized bed dryer. Dryer exhaust gases are passed through
a particulate collection device, usually a wet scrubber, for product
recovery and for pollution control.
The ammonium sulfate crystals are conveyed from the dryer to
an enclosure where they are screened to product specifications,
generally to coarse and fine products. The screening is enclosed
to control dust in the building.
4/81 Food and Agricultural Industry 6.18-1
-------
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6.18-2
EMISSION FACTORS
4/81
-------
6.18.2 Emissions and Controls
Ammonium sulfate particulate is the principal pollutant emitted
to the atmosphere from the manufacturing plants, nearly all of it
being contained in the gaseous exhaust of the dryers. Other plant
processes, such as evaporation, screening, and materials handling,
are not significant sources of emissions.
The particulate emission rate of a dryer depends on the gas
velocity and the particle size distribution. Since gas velocity
varies according to the dryer type, emission rates also vary.
Generally, the gas velocity of fluidized bed dryers is higher than
for most rotary drum dryers, and particulate emission rates are
also higher. The smaller the particle, the easier it is removed by
the gas stream of either type of dryer.
At caprolactam byproduct plants, volatile organic compounds
(VOC) are emitted from the dryers. Emissions of caprolactam vapor
are at least two orders of magnitude lower than the particulate
emissions.
Wet scrubbers, such as venturi and centrifuge, are most suitable
for reducing particulate emissions from the dryers. Wet scrubbers
use process streams as the scrubbing liquid. This allows the
collected particulate to be recycled easily to the production
system.
Table 6.18-1 shows the uncontrolled and controlled emission
factors for the various dryer types. The VOC emissions shown in
Table 6.18-1 apply only to caprolactam byproduct plants which may
use either a flu-idized bed or rotary drum dryer.
TABLE 6.18-1. EMISSION FACTORS FOR AMMONIUM SULFATE MANUFACTURE3
EMISSION FACTOR RATING: B
Particulates Volatile Organic Compounds
Dryer Type & Controls kg/MgIb/ton kg/MgIb/ton
Rotary dryers
Uncontrolled 23 46 0.74 1.48
Wet scrubber 0.12 0.24 0.11 0.22
Fluidized bed dryers
Uncontrolled
Wet scrubber
109
0.14
218
0.28
0.74
0.11
1.48
0.22
«a
Expressed as emissions by weight per unit of ammonium sulfate
, production by weight.
VOC emissions occur only at caprolactam plants using either type
of dryer. The emissions are caprolactam vapor.
4/81 Food and Agricultural Industry 6.18-3
-------
Reference for Section 6.18
1. Ammonium Sulfate Manufacture - Background Information for Proposed
Emission Standards, EPA-450/3-79-034a, U.S. Environmental Protection
Agency, Research Triangle Park, NC, December 1979.
6.18-4 EMISSION FACTORS 4/81
-------
7.1 PRIMARY ALUMINUM PRODUCTION
1 2
7.1.1 Process Description '
The base ore for primary aluminum production is bauxite, a
hydrated oxide of aluminum consisting of 30 to 70 percent alumina
(A^Og) and lesser amounts of iron, silicon and titanium. The
bauxite ore is first purified to alumina by the Bayer process, and
this is then reduced to elemental aluminum. The production of
alumina and the reduction of alumina to aluminum are seldom
accomplished at the same location. A schematic diagram of the
primary production of aluminum is shown at Figure 7.1-1.
In the Bayer process, the ore is dried, ground in ball mills
and mixed with sodium hydroxide to yield aluminum hydroxide. Iron
oxide, silica and other impurities are removed by settling, dilution
and filtration. Aluminum hydroxide is precipitated from the solution
by cooling and is then calcined to produce pure alumina, as in the
reaction:
2 A1(OH)3 - ^ 3 H20 + A1203 (1)
Aluminum hydroxide Water Alumina
Aluminum metal is manufactured by the Hall-Heroult process,
which involves the electrolytic reduction of alumina dissolved in a
molten salt bath of cryolite (Na-^AlF^) and various salt additives:
Electrolysis
2A1203 - * 4A1 + 302 (2)
Alumina Aluminum Oxygen
The electrolysis occurs in shallow rectangular cells, or "pots",
which are steel shells lined with carbon. Carbon blocks extending
into the pot serve as the anodes, and the carbon lining the steel
shell acts as the cathode. Cryolite functions as both the
electrolyte and the solvent for the alumina. Electrical resistance
to the current passing between the electrodes generates heat that
maintains cell operating temperatures between 950° and 1000°C
(1730° and 1830°F) . Aluminum is deposited at the cathode, where it
remains as molten metal below the surface of the cryolite bath.
The carbon anodes are continuously depleted by the reaction of
oxygen (formed during the reaction) and anode carbon, to produce
carbon monoxide and carbon dioxide. The carbon consumption and
other raw material and energy requirements for aluminum production
are summarized in Table 7.1-1. The aluminum product is periodically
tapped beneath the cryolite cover and is fluxed to remove trace
impurities.
4/81 Metallurgical Industry 7.1-1
-------
SODIUM
HYDROXIDE
BAUXITE
TO CONTROL DEVICE
I
SETTLING
CHAMBER
DILUTION
WATER
RED MUD
(IMPURITIES)
DILUTE
SODIUM
HYDROXIDE
i
TO CONTROL
DEVICE
CRYSTALLIZER
AQUEOUS SODIUM
ALUMINATE
TO CONTROL DEVICE
BAKING
FURNACE
BAKED
ANODES
TO CONTROL DEVICE
_L
PREBAKE
REDUCTION
CELL
ANODE PASTE
TO CONTROL DEVICE
HORIZONTAL
OR VERTICAL
SODERBERG
REDUCTION CELL
MOLTEN
ALUMINUM
Figure 7.1-1. Schematic diagram of primary aluminum production process.
7.1-2
Metallurgical Industry
4/81
-------
TABLE 7.1-1.
RAW MATERIAL AND ENERGY REQUIREMENTS FOR
ALUMINUM PRODUCTION
Parameter
Typical value
Cell operating temperature
Current through pot line
Voltage drop per cell
Current efficiency
Energy required
~950°C (~1740°F)
60,000 - 125,000 amperes
4.3 - 5.2
85 - 90%
13.2 - 18.7 kwh/kg aluminum
(6.0 - 8.5 kwh/lb aluminum)
Weight alumina consumed 1.89 - 1.92 kg (Ib) AL203/kg (Ib) aluminum
Weight electrolyte
fluoride consumed
0.03 - 0.10 kg (Ib) fluoride/kg (Ib) aluminum
Weight carbon electrode
consumed 0.45
- 0.55 kg (Ib) electrode/kg (Ib) aluminum
Aluminum reduction cells are distinguished by the anode
configuration used in the pots. Three types of pots are currently
used, prebaked (PB), horizontal stud Soderberg (HSS), and vertical
stud Soderberg (VSS). Most of the aluminum produced in the U. S.
is processed in PB cells. These cells use anodes that are press
formed from a carbon paste and baked in a direct fired ring furnace
or indirect fired tunnel kiln. Volatile organic vapors from the
coke and pitch paste comprising the anodes are emitted, and most
are destroyed in the baking furnace. The baked anodes, typically
14 to 24 per cell, are attached to metal rods and serve as
replaceable anodes.
In reduction, the carbon anodes are lowered into the cell and
consumed at a rate of about 2.5 cm (1 in.) per day. Prebaked cells
are preferred over Soderberg cells for their lower power requirements,
reduced generation of volatile pitch vapors from the carbon anodes,
and provision for better cell hooding to capture emissions.
The second most commonly used reduction cell is the horizontal
stud Soderberg. This type of cell uses a "continuous" carbon
anode. A green anode paste of pitch and coke is periodically added
at the top of the superstructure and is baked by the heat of the
cell to a solid mass as the material moves down the casing. The
cell casing consists of aluminum sheeting and perforated steel
channels, through which electrode connections or studs are inserted
horizontally into the anode paste. During reduction, as the baking
anode is lowered, the lower row of studs and the bottom channel are
removed and the flexible electrical connectors are moved to a
4/81
Metallurgical Industry
7.1-3
-------
higher row. Heavy organics from the anode paste are added to the
cell emissions. The heavy tars can cause plugging of ducts, fans
and emission control equipment.
The vertical stud Soderberg cell is similar to the HSS cell,
except that the studs are mounted vertically in the anode paste.
Gases from the VSS cells can be ducted to gas burners and the tars
and oils combusted. The construction of the VSS cell prevents the
installation of an integral gas collection device, and hooding is
restricted to a canopy or skirt at the base of the cell where the
hot anode enters the cell bath.
1-3 9
7.1.2 Emissions and Controls '
Controlled and uncontrolled emission factors for sulfur oxides,
fluorides and total particulates are presented in Table 7.1-2.
Fugitive particulate and fluoride emission factors for reduction
cells are also presented in this table.
Emissions from aluminum reduction processes consist primarily
of gaseous hydrogen fluoride and particulate fluorides, alumina,
carbon monoxide, hydrocarbons or organics, and sulfur dioxide from
the reduction cells and the anode baking furnaces. Large amounts
of particulates are also generated during the calcining of aluminum
hydroxide, but the economic value of this dust is such that extensive
controls have been employed to reduce emissions to relatively small
quantities. Small amounts of particulates are emitted from the
bauxite grinding and materials handling processes.
The source of fluoride emissions from reduction cells is the
fluoride electrolyte, which contains cryolite, aluminum fluoride
(A1F3), and fluorspar (CaF2). For normal operation, the weight, or
"bath", ratio of sodium fluoride (NaF) to AlF^ is maintained between
1.36 and 1.43 by the addition of Na2C03, NaF and A1F3. Experience
has shown that increasing this ratio has the effect of decreasing
total fluoride effluents. Cell fluoride emissions are also decreased
by lowering the operating temperature and increasing the alumina
content in the bath. Specifically, the ratio of gaseous (mainly
hydrogen fluoride and silicon tetrafluoride) to particulate fluorides
varies from 1.2 to 1.7 with PB and HSS cells, but attains a value
of approximately 3.0 with VSS cells.
Particulate emissions from reduction cells consist of alumina
and carbon from anode dusting, cryolite, aluminum fluoride, calcium
fluoride, chiolite (NarAloF^) and ferric oxide. Representative
size distributions for particulate emissions from PB cells and HSS
cells are presented in Table 7.1-3. Particulates less than 1 micron
in diameter represent the largest fraction (35 - 44 percent) of
uncontrolled emissions. Uncontrolled particulate emissions from
one HSS cell had a mass mean particle diameter of 5.5 microns.
Thirty percent by mass of the particles were submicron, and 16 percent
were less than 0.2^ in diameter.'
7.1-4 EMISSION FACTORS 4/81
-------
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Metallurgical Industry
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4/81
-------
Emissions from reduction cells also include hydrocarbons or
organics, carbon monoxide and sulfur oxides. Small amounts of
hydrocarbons are released by PB pots, and larger amounts are emitted
from HSS and VSS pots. In vertical cells, these organics are
incinerated in integral gas burners. Sulfur oxides originate from
sulfur in the anode coke and pitch. The concentrations of sulfur
oxides in VSS cell emissions range from 200 to 300 ppm. Emissions
from PB plants usually have S02 concentrations ranging from 20 to
30 ppm.
TABLE 7.1-3. REPRESENTATIVE PARTICLE SIZE DISTRIBUTIONS
OF UNCONTROLLED EMISSIONS FROM PREBAKED AND
HORIZONTAL STUD SODERBERG CELLS*
Particles (wt %)
Size range (M) PB HSS
<1
1 to 5
5 to 10
10 to 20
20 to 44
>44
35
25
8
5
5
22
44
26
8
6
4
12
*1
Reference 1.
Emissions from anode bake ovens include the products of fuel
combustion, high boiling organics from the cracking, distillation
and oxidation af paste binder pitch, sulfur dioxide from the carbon
paste, fluorides from recycled anode butts, and other particulate
matter. The concentrations of uncontrolled emissions of S02 from
anode baking furnaces range from 5 to 47 ppm (based on 3 percent
sulfur in coke).°
Casting emissions are mainly fumes of aluminum chloride, which
may hydrolyze to HC1 and A1203.
A variety of control devices has been used to abate emissions
from reduction cells and anode baking furnaces. To control gaseous
and particulate fluorides and particulate emissions, one or more
types of wet scrubbers (spray tower and chambers, quench towers,
floating beds, packed beds, Venturis, and self induced sprays) have
been applied to all three types of reduction cells and to anode
baking furnaces. Also, particulate control methods such as
electrostatic precipitators (wet and dry), multiple cyclones and
dry alumina scrubbers (fluid bed, injected, and coated filter
types) have been employed with baking furnaces and on all three
cell types. Also, the alumina adsorption systems are being used on
all three cell types for controlling both gaseous and particulate
fluorides by passing the pot offgases through the entering alumina
4/81 Metallurgical Industry 7.1-7
-------
feed, on which the fluorides are absorbed. This technique has an
overall control efficiency of 98 to 99 percent. Baghouses are
then used to collect residual fluorides entrained in the alumina
and to recycle them to the reduction cells. Wet electrostatic pre-
cipitators approach adsorption in particulate removal efficiency
but must be coupled to a wet scrubber or coated baghouse to catch
hydrogen fluoride.
Scrubber systems also remove a portion of the S02 emissions.
These emissions could be reduced by wet scrubbing or by reducing the
quantity of sulfur in the anode coke and pitch, i.e., calcinating
the coke.
In the aluminum hydroxide calcining, bauxite grinding and
materials handling operations, various dry dust collection devices
such as centrifugal collectors, multiple cyclones, or electrostatic
precipitators and/or wet scrubbers have been used.
Potential sources of fugitive particulate emissions in the
primary aluminum industry are bauxite grinding, materials handling,
anode baking and the three types of reduction cells (see Table 7.1-2),
These fugitives probably have particle size distribution similar to
those presented in Table 7.1-3.
References for Section 7.1
1. Engineering and Cost Effectiveness Study of Fluoride Emissions
Control, Vol. I, APTD-0945, U.S. Environmental Protection Agency,
Research Triangle Park, NC, January 1972.
2. Air Pollution Control in the Primary Aluminum Industry, Vol. I,
EPA-450/3-73-004a, U.S. Environmental Protection Agency, Research
Triangle Park, NC, July 1973.
3. Particulate Pollutant System Study, Vol. I, APTD-0743, U.S.
Environmental Protection Agency, Research Triangle Park, NC,
May 1971.
4. Emissions from Wet Scrubbing System, Report Number Y-7730-E,
York Research Corp., Stamford, CT, May 1972.
5. Emissions from Primary Aluminum Smelting Plant, Report Number
Y-7730-B, York Research Corp., Stamford, CT, June 1972.
6. Emissions from the Wet Scrubber System, Report Number Y-7730-F,
York Research Corp., Stamford, CT, June 1972.
7. T.R. Hanna and M.J. Pilat, "Size Distribution of Particulates
Emitted from a Horizontal Spike Soderberg Aluminum Reduction
Cell", JAPCA, _22_: 533-536, July 1972.
7.1-8 EMISSION FACTORS 4/81
-------
8. Background Information for Standards of Performance: Primary
Aluminum Industry, Volume I: Proposed Standards, EPA 450/2-74-020a,
U.S. Environmental Protection Agency, Research Triangle Park,
NC, October 1974.
9. Primary Aluminum: Guidelines for Control of Fluoride Emissions
from Existing Primary Aluminum Plants, EPA-450/2-78-049b, U.S.
Environmental Protection Agency, Research Triangle Park, NC,
December 1979.
4/81 Metallurgical Industry 7.1-9
-------
-------
7.8 SECONDARY ALUMINUM OPERATIONS
7.8.1 General
Secondary aluminum operations involve the cleaning, melting,
refining and pouring of aluminum recovered from scrap. The processes
used to convert scrap aluminum to secondary aluminum products such
as lightweight metal alloys for industrial castings and ingots are
presented in Figure 7.8-1. Production involves two general classes
of operation, scrap treatment and smelting/refining.
Scrap treatment involves receiving, sorting and processing
scrap to remove contaminants and to prepare the material for smelting.
Processes based on mechanical, pyrometallurgical and hydrometal-
lurgical techniques are used, and those employed are selected to
suit the type of scrap processed.
The smelting/refining operation generally involves the following
steps:
charging mixing
melting demagging
fluxing degassing
alloying skimming
pouring
All of these steps may be involved in each operation, with process
distinctions being in the furnace type used and in emission charac-
teristics. However, as with scrap treatment, not all of these
steps are necessarily incorporated into the operations at a
particular plant. Some steps may be combined or reordered, depending
on furnace design, scrap quality, process inputs and product
specifications.
Scrap treatment - Purchased aluminum scrap undergoes inspection
upon delivery. Clean scrap requiring no treatment is transported
to storage or is charged directly into the smelting furnace. The
bulk of the scrap, however, must be manually sorted as it passes
along a steel belt conveyor. Free iron, stainless steel, zinc,
brass and oversized materials are removed. The sorted scrap then
goes to appropriate scrap treating processes or is charged directly
to the smelting furnace.
Sorted scrap is conveyed to a ring crusher or hammer mill,
where the material is shredded and crushed, with the iron torn away
from the aluminum. The crushed material is passed over vibrating
screens to remove dirt and fines, and tramp iron is removed by
magnetic drums and/or belt separators. Baling equipment compacts
bulky aluminum scrap into 1x2 meter (3x6 foot) bales.
4/81 Metallurgical Industry 7.8-1
-------
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EMISSION FACTORS
4/81
-------
Pure aluminum cable with steel reinforcement or insulation is
cut by alligator type shears and granulated or further reduced in
hammer mills, to separate the iron core and the plastic coating
from the aluminum. Magnetic processing accomplishes iron removal,
and air classification separates the insulation.
Borings and turnings, in most cases, are treated to remove
cutting oils, greases, moisture and free iron. The processing
steps involved are (a) crushing in hammer mills or ring crushers,
(b) volatilizing the moisture and organics in a gas or oil fired
rotary dryer, (c) screening the dried chips to remove aluminum
fines, (d) removing iron magnetically and (e) storing the clean
dried borings in tote boxes.
Aluminum can be recovered from the hot dross discharged from a
refining furnace by batch fluxing with a salt/cryolite mixture in a
mechanically rotated, refractory lined barrel furnace. The metal
is tapped periodically through a hole in its base. Secondary
aluminum recovery from cold dross and other residues from primary
aluminum plants is carried out by means of this batch fluxing in a
rotary furnace. In the dry milling process, cold aluminum laden
dross and other residues are processed by milling, screening and
concentrating to obtain a product containing at least 60-70 percent
aluminum. Ball, rod or hammer mills can be used to reduce oxides
and nonmetallics to fine powders. Separation of dirt and other
unrecoverables from the metal is achieved by screening, air
classification and/or magnetic separation.
Leaching involves (a) wet milling, (b) screening, (c) drying
and (d) magnetic separation to remove fluxing salts and other non-
recoverables from drosses, skimmings and slags. First, the raw
material is fed into a long rotating drum or an attrition or ball
mill where soluble contaminants are leached. The washed material
is then screened to remove fines and dissolved salts and is dried
and passed through a magnetic separator to remove ferrous materials.
The nonmagnetics then are stored or charged directly to the smelting
furnace.
In the roasting process, carbonaceous materials associated
with aluminum foil are charred and then separated from the metal
product.
Sweating is a pyrometallurgical process used to recover
aluminum from high iron content scrap. Open flame reverberatory
furnaces may be used. Separation is accomplished as aluminum and
other low melting constituents melt and trickle down the hearth,
through a grate and into air cooled molds or collecting pots. This
product is termed "sweated pig". The higher melting materials,
including iron, brass and oxidation products formed during the
sweating process, are periodically removed from the furnace.
4/81 Metallurgical Industry 7.8-3
-------
Smelting/refining - In reverberatory (chlorine) operations,
reverberatory furnaces are commonly used to convert clean sorted
scrap, sweated pigs or some untreated scrap to specification ingots,
shot or hot metal. The scrap is first charged to the furnace by
some mechanical means, often through charging wells designed to
permit introduction of chips and light scrap below the surface of a
previously melted charge ("heel"). Batch processing is generally
practiced for alloy ingot production, and continuous feeding and
pouring are generally used for products having less strict
specifications.
Cover fluxes are used to prevent air contact with and consequent
oxidation of the melt. Solvent fluxes react with nonmetallies such
as burned coating residues and dirt to form insolubles which float
to the surface as part of the slag.
Alloying agents are charged through the forewell in amounts
determined by product specifications. Injection of nitrogen or
other inert gases into the molten metal can be used to aid in
raising dissolved gases (typically hydrogen) and intermixed solids
to the surface.
Demagging reduces the magnesium content of the molten charge
from approximately 0.3 to 0.5 percent (typical scrap value) to
about 0.1 percent (typical product line alloy specification). When
demagging with chlorine gas, chlorine is injected under pressure
through carbon lances to react with magnesium and aluminum as it
bubbles to the surface. Other chlorinating agents, or fluxes, are
sometimes used, such as anhydrous aluminum chloride or chlorinated
organics.
In the skimming step, contaminated semisolid fluxes (dross,
slag or skimmings) are ladled from the surface of the melt and
removed through the forewell. The melt is then cooled before
pouring.
The reverberatory (fluorine) process is similar to the
reverberatory (chlorine) smelting/refining process, except that
aluminum fluoride (AlFo) is employed in the demagging step instead
of chlorine. The AlF-j reacts with magnesium to produce molten
metal aluminum and solid magnesium fluoride salt which floats to
the surface of the molten aluminum and is skimmed off.
The crucible smelting/refining process is used to raelt small
batches of aluminum scrap, generally limited to 500 kg (1000 Ib) or
less. The metal treating process steps are essentially the same as
those of reverberatory furnaces.
The induction smelting/refining process is designed to produce
hardeners by blending pure aluminum and hardening agents in an
electric induction furnace. The process steps include charging
scrap to the furnace, melting, adding and blending the hardening
agent, skimming, pouring and casting into notched bars.
7.8-4 EMISSION FACTORS 4/81
-------
7.8.2 Emissions and Controls
Table 7.8-1 presents emission factors for the principal
emission sources in secondary aluminum operations. Although each
step in scrap treatment and smelting/refining is a potential source
of emissions, emissions from most of the processing operations are
either not characterized here or emit only small amounts of
pollutants.
Crushing/screening produces small amounts of metallic and
nonmetallic dust. Baling operations produce particulate emissions,
primarily dirt and alumina dust resulting from aluminum oxidation.
Shredding/classifying also emits small amounts of dust. Emissions
from these processing steps are normally uncontrolled.
Burning/drying operations emit a wide range of pollutants.
Afterburners are used generally to convert unburned hydrocarbons to
CC>2 and l^O. Other gases potentially present, depending on the
composition of the organic contaminants, include chlorides, fluo-
rides and sulfur oxides. Oxidized aluminum fines blown out of the
dryer by the combustion gases comprise particulate emissions. Wet
scrubbers are sometimes used in place of afterburners.
Mechanically generated dust from the rotating barrel dross
furnace constitutes the main air emission of hot dross processing.
Some fumes are produced from the fluxing reactions. Fugitive emis-
sions are controlled by enclosing the barrel in a hood system and
by ducting the stream to a baghouse. Furnace offgas emissions,
mainly fluxing salt fume, are controlled by a venturi scrubber.
In dry milling, large amounts of dust are generated from the
crushing, milling, screening, air classification and materials
transfer steps. Leaching operations may produce particulate emis-
sions during drying. Emissions from roasting are particulates from
the charring of carbonaceous materials.
Emissions from sweating furnaces vary with the feed scrap
composition. Smoke may result from incomplete combustion of organic
contaminants (e.g., rubber, oil and grease, plastics, paint, card-
board, paper) which may be present. Fumes can result from oxidation
of magnesium and zinc contaminants and from fluxes in recovered
drosses and skims.
Atmospheric emissions from reverberatory (chlorine) smelting/
refining represent a significant fraction of the total particulate
and gaseous effluents generated in the secondary aluminum industry.
Typical furnace effluent gases contain combustion products, chlorine,
hydrogen chloride and metal chlorides of zinc, magnesium and aluminum,
aluminum oxide and various metals and metal compounds, depending on
the quality of scrap charged. Particulate emissions from one
secondary aluminum smelter have a size distribution of D = 0.4n.
4/81 Metallurgical Industry 7.8-5
-------
TABLE 7.8-1.
PARTICIPATE EMISSION FACTORS FOR SECONDARY
ALUMINUM OPERATIONS3
Electrostatic Emission
Uncontrolled
Operation
Sweating furnace
Smelting
Crucible furnace
Reverberatory furnace
Chlorination station
kg/Mg
7.25
0.95
2.15
500
Ib/ton
14.5
1.9
4.3
1000
Baghouse precipitator Factor
kg/Mg
1.65
_
0.65s
25
Ib/ton kg/Mg
3.3
_
1.3e 0.65
50
Ib/ton Rating
C
_ r
1.3 B
B
Reference 2. Emission factors expressed as units per unit weight of metal
.processed. Factors apply only to Al metal recovery operations.
Based on averages of two source tests.
Based on averages of ten source tests. Standard deviation of uncontrolled
emission factor is 17.5 kg/Mg (3.5 Ib/ton), that of controlled factor is 0.15 kg/Mg
d(0.3 Ib/ton).
Expressed as kg/Mg (Ib/ton) of chlorine used. Based on averages of ten source tests.
Standard deviation of uncontrolled emission factor is 215 kg/Mg (430 Ib/ton), of
Controlled factor, 18 kg/Mg (36 Ib/ton).
6This factor may be lower if a coated baghouse is used.
Emissions from reverberatory (fluorine) smelting/refining are
similar to those from reverberatory (chlorine) smelting/refining.
The use of A1F3 rather than chlorine in the demagging step reduces
demagging emissions. Fluorides are emitted as gaseous fluorides
(hydrogen fluoride, aluminum and magnesium fluoride vapors, and
silicon tetrafluoride) or as dusts. Venturi scrubbers are usually
used for fluoride emission control.
References for Section 7.8
1. W.M. Coltharp, et al., Multimedia Environmental Assessment of
the Secondary Nonferrous Metal Industry, Draft Final Report,
2 vols., EPA Contract No. 68-02-1319, Radian Corporation,
Austin, TX, June 1976.
2. W.F. Hammond and S.M. Weiss, Unpublished report on air
contaminant emissions from metallurgical operations in Los
Angeles County, Los Angeles County Air Pollution Control
District, July 1964.
3. R.A. Baker, et al., Evaluation of a Coated Baghouse at a
Secondary Aluminum Smelter, EPA Contract No. 68-02-1402,
Environmental Science and Engineering, Inc., Gainesville, FL,
October 1976.
4. Air Pollution Engineering Manual, 2d Edition, AP-40, U.S.
Environmental Protection Agency, Research Triangle Park, NC,
May 1973. Out of Print.
7.8-6 EMISSION FACTORS 4/81
-------
5. E.J. Petkus, "Precoated Baghouse Control for Secondary Aluminum
Smelting", Presented at the 71st Annual Meeting of the Air
Pollution Control Association, Houston, TX, June 1978.
4/81 Metallurgical Industry 7.8-7
-v-
-------
-------
7.10 GRAY IRON FOUNDRIES
7.10.1 General1
Gray iron foundries produce gray iron castings by melting,
alloying and molding pig iron and scrap iron. The process flow
diagram of a typical gray iron foundry is presented in Figure 7.10-1.
The four major processing operations of the typical gray iron
foundry are raw materials handling, metal melting, mold and core
production, and casting and finishing.
Raw Materials Handling - The raw material handling operations
include the receiving, unloading, storage and conveying of all raw
materials for the foundry. The raw materials used by gray iron
foundries are pig iron, iron and steel scrap, foundry returns,
metal turnings, alloys, carbon additives, coke, fluxes (limestone,
soda ash, fluorspar, calcium carbide), sand, sand additives, and
binders. These raw materials are received in ships, railcars,
trucks and containers, transferred by truck, loaders and conveyers
to both open piles and enclosed storage areas, and then transferred
by similar means from storage to the processes.
Metal Melting - Generally the first step in the metal melting
operations is scrap preparation. Since scrap is normally purchased
in the proper size for furnace feed, scrap preparation primarily
consists of scrap degreasing. This is very important for electric
induction furnaces, as organics on scrap can cause an explosion.
Scrap may be degreased with solvents, by centrifugation or by
combustion in an incinerator or heater, or it may be charged with-
out treatment, as is often the case with cupola furnaces. After
preparation, the scrap, iron, alloy and flux are weighed and charged
to the furnace.
The cupola furnace is the major type of furnace used in the
gray iron industry today. It is typically a vertical refractory
lined cylindrical steel shell, charged at the top with alternate
layers of metal, coke and flux, larger cupolas are water cooled
instead of refractory lined. Air introduced at the bottom of the
cupola burns the coke to melt the metal charge. Typical melting
capacities range from 0.5 to 14 Mg (1 - 27 tons) per hour, with a
few larger units approaching 50 Mg (100 tons) per hour. Cupolas
can be tapped either continuously or intermittently from a side
tap hole at the bottom of the furnace.
Electric arc furnaces, used to a lesser degree in the gray
iron industry, are large refractory lined steel pots fitted with a
refractory lined roof through which three graphite electrodes are
inserted. The metal charge is heated to melting by electrical arcs
produced by the current flowing between the electrodes and the
charge. Electric arc furnaces are charged with raw material through
the removed lid, by a chute through the lid, or through a door in
4/81 Metallurgical Industry 7.10-1
-------
RAW MATERIALS
UNLOADING, STORAGE,
TRANSFER
FLUX
METALLICS
CARBON SOURCES
SAND
BINDER
FUGITIVE
DUST
I
j -^HYDROCARBONS
I AND SMOKE
SCRAP
PREPARATION
1 FUMES AND-*
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DUST
-»-FURNANCE
VENT
FURIUAIUCE
CUPOLA
ELECTRIC ARC
INDUCTION
OTHER
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TREATING
MOLD POURING,
COOLING
FUGITIVE FUMES
AND DUST
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AND DUST
OVEN VENT
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SHAKEOUT
-*-FUGITIVE
DUST
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+. FUMES AND
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CLEANING,
FINISHING
->-FUGITIVE
DUST
SHIPPING
Figure 7.10-1. Typical flow diagram of a grey iron foundry.
7,10-2
EMISSION FACTORS
4/81
-------
the side. The molten metal is tapped by tilting and pouring through
a hole in the side. Melting capacities range up to 10 Mg (20 tons)
per hour.
A third furnace type used in the gray iron industry is the
electric induction furnace. Induction furnaces are vertical refrac-
tory lined cylinders surrounded by electrical coils energized with
alternating current. The resulting fluctuating magnetic field
heats the metal. Induction furnaces are kept closed except when
charging, skimming and tapping. The molten metal is tapped by
tilting and pouring through a hole in the side. Induction furnaces
are also used with other furnaces to hold and superheat the charge
after melting and refining in another furnace.
A small percentage of melting in the gray iron industry is
also done in air furnaces, reverberatory furnaces, pot furnaces and
indirect arc furnaces.
The basic melting process operations are 1) furnace charging,
in which the metal, scrap, alloys, carbon and flux are added to the
furnace, 2) melting, during which the furnace remains closed,
3) backcharging, which involves the addition of more metal and,
possibly, alloys, 4) refining and treating, during which the chemis-
try is adjusted, 5) slag removing, and 6) tapping molten metal into
a ladle or directly into molds.
Mold and Core Production - Cores are molded sand shapes used to
make the internal voids in castings, and molds are forms used to
shape the exterior of castings. Cores are made by mixing sand with
organic binders, molding the sand into a core, and baking the core
in an oven. Molds are prepared by using a mixture of wet sand,
clay and organic additives to make the mold shapes, and then by
drying with hot air. Increasingly, cold setting binders are being
used in both core and mold production. Used sand from shakeout
operations is recycled to the sand preparation area to be cleaned,
screened and reused to make molds.
Casting and Finishing - When the melting process is complete, the
molten metal is tapped and poured into a ladle. At this point, the
molten metal may be treated by addition of magnesium to produce
ductile iron by the addition of soda ash or lime to remove sulfur.
At times, graphite may be innoculated to adjust carbon levels. The
treated molten metal is then poured into molds and allowed partially
to cool. The partially cooled castings are placed on a vibrating
grid where the mold and core sand is shaken away from the casting.
The sand is returned to the mold manufacturing process, and the
castings are allowed to cool further in a cooling tunnel.
In the cleaning and finishing process, burrs, risers and gates
are broken off or ground off to match the contours of the castings,
after which the castings are shot blasted to remove remaining mold
sand and scale.
4/81 Metallurgical Industry 7.10-3
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EMISSION FACTORS
4/81
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Metallurgical Industry
7.10-5
-------
7.10.2 Emissions and Controls
Emissions from the raw materials handling operations consist
of fugitive particulates generated from the receiving, unloading,
storage and conveying of all raw materials for the foundry. These
emissions are controlled by enclosing the major emission points and
routing the air from the enclosures through fabric filters or wet
collectors.
Scrap preparation using heat will emit smoke, organics and
carbon monoxide, and preparation using solvent degreasers will emit
organics. (See Section 4.6, Solvent Degreasing.) Catalytic incinera-
tors and afterburners can be applied to control about 95 percent of
the organics and carbon monoxide.
Emissions from melting furnaces consist of particulates,
carbon monoxide, organics, sulfur dioxide, nitrogen oxides and
small quantities of chlorides and fluorides. The particulates,
chlorides and fluorides are generated by flux, incomplete combustion
of coke, carbon additives, and dirt and scale on the scrap charge.
Organics on the scrap and the reactivity of the coke effect carbon
monoxide emissions. Sulfur dioxide emissions, characteristic of
cupola furnaces, are attributable to sulfur in the coke.
The highest concentration of furnace emissions occurs during
charging, backcharging, alloying, slag removal, and tapping opera-
tions, when the furnace lids and doors are opened. Generally,
these emissions have escaped into the furnace building and have
been vented through roof vents. Controls for emissions during the
melting and refining operations usually concern venting the furnace
gases and fumes directly to a collection and control system.
Controls for fugitive furnace emissions involve the use of roof
hoods or special hoods in the proximity of the furnace doors, and
of tapping ladles to capture emissions and to route them to emission
control systems.
High energy scrubbers and bag filters with respective effi-
ciencies greater than 95 percent and 98 percent are used to control
particulate emissions from cupolas and electric arc furnaces in the
U.S. Afterburners achieving 95 percent control are used for reducing
organics and carbon monoxide emissions from cupolas. Normally,
induction furnaces are uncontrolled.
The major pollutants from mold and core production are particu-
lates from sand reclaiming, sand preparation, sand mixing with
binders and additives, and mold and core forming. There are organics,
CO and particulate emissions from core baking, and organic emissions
from mold drying. Bag filters and high energy scrubbers can be
used to control particulates from mold and core production.
Afterburners and catalytic incinerators can be used to control
organics and carbon monoxide emissions.
7.10-6 EMISSION FACTORS 4/81
-------
TABLE 7.10-3. SIZE DISTRIBUTION FOR PARTICULATE EMISSIONS FROM
THREE ELECTRIC ARC FURNACE INSTALLATIONS21
Particle Size (u)
<1
<2
<5
<10
<15
<20
<50
Foundry A
5
15
28
41
55
68
98
Foundry B
8
54
80
89
93
96
99
Foundry C
18
61
84
91
94
96
99
Reference 1, p. 111-39.
TABLE 7.10-4. SIZE DISTRIBUTION FOR PARTICULATE
EMISSIONS FROM EIGHTEEN CUPOLA FURNACE INSTALLATIONS3
Cumulative % Less
Particle Size (|-i) Than Indicated Size
<2
<5
<10
<20
<50
<100
<200
14
24
34
44
61
78
93
Reference 1, p. 111-33.
4/81 Metallurgical Industry 7.10-7
-------
In the casting operations, large quantities of particulates
can be generated in the treating and innoculation steps before
pouring. Emissions from pouring consist of fumes, carbon monoxide,
organics, and particulates evolved from the mold and core materials
when contacted with molten iron. These emissions continue to
evolve as the mold cools. A significant quantity of particulate
emissions is also generated during the casting shakeout operation.
Particulate emissions from shakeout can be controlled by either
high energy scrubbers or bag filters. Emissions from pouring are
normally uncontrolled or are ducted into other exhaust streams.
Emissions from finishing operations are of large particulates
emitted during the removal of burrs, risers and gates, and during
the blasting process. Particulates from finishing operations are
usually large in size and are easily controlled by cyclones.
Emission factors for melting furnaces are presented in
Table 7.10-1, and emission factors for fugitive particulates are
presented in Table 7.10-2. Typical particle size distributions for
emissions from electric arc and cupola furnaces are presented in
Table 7.10-3 and Table 7.10-4.
References for Section 7.10
1. J.A. Davis, et al., Screening Study on Cupolas and Electric
Furnaces in Gray Iron Foundries, EPA Contract No. 68-01-0611,
Battelle Laboratories, Columbus, OH, August 1975.
2. W.F. Hammond and S.M. Weiss, "Air Contaminant Emissions from
Metallurgical Operations in Los Angeles County", Presented at
Air Pollution Control Institute, Los Angeles, CA, July 1964.
3. H.R. Crabaugh, et al., "Dust and Fumes from Gray Iron Cupolas:
How They Are Controlled in Los Angeles County", Air Repair,
4.(3): 125-130, November 1954.
4. Air Pollution Engineering Manual, Second Edition, AP-40, U.S.
Environmental Protection Agency, Research Triangle Park, NC,
May 1973. Out of Print.
5. J.M. Kane, "Equipment for Cupola Control", American Foundryman's
Society Transactions, j)4_:525-531, 1956.
6. Air Pollution Aspects of the Iron Foundry Industry, APTD-0806,
U.S. Environmental Protection Agency, Research Triangle Park,
NC, February 1971.
7. John Zoller, et al., Assessment of Fugitive Particulate Emission
Factors for Industrial Processes, EPA-450/3-78-107, U.S.
Environmental Protection Agency, Research Triangle Park, NC,
September 1978.
7.10-8 EMISSION FACTORS 4/81
-------
8. P.F. Fennelly and P.D. Spawn, Air Pollutant Control Techniques
for Electric Arc Furnaces in the Iron and Steel Foundry Industry,
EPA 450/2-78-024, U.S. Environmental Protection Agency, Research
Triangle Park, NC, June 1978.
9. Control Techniques for lead Air Emissions, Volumes 1 and 2,
EPA-450/2-77-012, U.S. Environmental Protection Agency, Research
Triangle Park, NC, December 1977.
10. W.E. Davis, Emissions Study of Industrial Sources of lead Air
Pollutants, 1970, APTD-1543, U.S. Environmental Protection
Agency, Research Triangle Park, NC, April 1973.
11. Emission Test No. 71-CI-27, Office of Air Quality Planning and
Standards, U.S. Environmental Protection Agency, Research
Triangle Park, NC, February 1972.
12. Emission Test No. 71-CI-30, Office of Air Quality Planning
and Standards, U.S. Environmental Protection Agency, Research
Triangle Park, NC, March 1972.
4/81 Metallurgical Industry 7.10-9
-------
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10/80
Metallurgical Industry
7.11-7
-------
Table 7.11-4. PARTICLE SIZE DISTRIBUTION OF PARTICULATES
RECOVERED FROM A COMBINED BLAST AND REVERBERATORY
FURNACE GAS STREAM WITH BAGHOUSE CONTROL'1
Particle Size Range, ym
Fabric filter catch, wt %
0 to
1 to
2 to
3 to
4 to
1
2
3
4
16
13.
45.
19.
14.
8.
3
2
1
0
4
Reference 4, Table 86.
References for Section 7.11
1. William M. Coltharp, et al., Multimedia Environmentsil Assessment
of the Secondary Nonferrous Metal Industry (Draft), 2 Volumes, EPA
Contract No. 68-02-1319, Radian Corporation, Austin,, TX, June 1976.
2. H. Nack, et al., Development of an Approach to Identification of
Emerging Technology and Demonstration Opportunities,, EPA-650/2-74-
048, U.S. Environmental Protection Agency, Research Triangle Park,
NC, May 1974.
3. J. M. Zoller, et al., A Method of Characterization and Quantifi-
cation of Fugitive Lead Emissions from Secondary Lead Smelters,
Ferroalloy Plants and Gray Iron Foundries (Revised), EPA-450/3-78-
003 (Revised), U.S. Environmental Protection Agency, Research
Triangle Park, NC, August 1978.
4. John A. Danielson, editor, Air Pollution Engineering Manual, Second
Edition, AP-40, U.S. Environmental Protection Agency, Research
Triangle Park, NC, May 1973, pp. 299-304. Out of Print.
5. Control Techniques for Lead Air Emissions, EPA-450/2-77-012, U.S.
Environmental Protection Agency, Research Triangle Park, NC,
January 1978.
6. Background Information for Proposed New Source Performance Standards,
Volume I; Secondary Lead Smelters and Refineries, APTD-1352, U.S.
Environmental Protection Agency, Research Triangle Park, NC, June
1973.
7.11-8
EMISSION FACTORS
10/80
-------
7.13 STEEL FOUNDRIES
7.13.1 Process Description
Steel foundries produce steel castings by the melting, alloying
and molding of pig iron and steel scrap. The process flow diagram
of a typical steel foundry is presented in Figure 7.13-1. The
major processing operations of the typical steel foundry are raw
materials handling, metal melting, mold and core production, and
casting and finishing.
Raw Materials Handling - The raw material handling operations
include the receiving, unloading, storage and conveying of all raw
materials for the foundry. Some of the raw materials used by steel
foundries are pig iron, iron and steel scrap, foundry returns,
metal turnings, alloys, carbon additives, fluxes (limestone, soda
ash, fluorspar, calcium carbide), sand, sand additives, and binders.
These raw materials are received in ships, railcars, trucks, and
containers, and are transferred by trucks, loaders, and conveyors
to both open pile and enclosed storage areas. They are then
transferred by similar means from storage to the subsequent processes,
Metal Melting - Generally, the first step in the metal melting
operations is scrap preparation. Since scrap is normally purchased
in the proper size for furnace feed, preparation primarily consists
of scrap degreasing. This is very important for electric induction
furnaces, as organics on scrap can be explosive. Scrap may be
degreased with solvents, by centrifugation or by incinerator or
preheater combustion. After preparation, the scrap, metal, alloy,
and flux are weighed and charged to the furnace.
Electric arc furnaces are used almost exclusively in the steel
foundry for melting and formulating steel. Electric arc furnaces
are large refractory lined steel pots, fitted with a refractory
roof through which three graphite electrodes are inserted. The
metal charge is melted with resistive heating generated by electrical
current flowing among the electrodes and through the charge.
Electric arc furnaces are charged with raw materials by removing
the lid, through a chute opening in the lid, or through a door in
the side. The molten metal is tapped by tilting and pouring
through a hole in the side. Melting capacities range up to
10 megagrams (11 tons) per hour.
A second, less common, furnace used in steel foundries is the
open hearth furnace, a very large shallow refractory lined vessel
which is operated in a batch manner. The open hearth furnace is
fired at alternate ends, using the heat from the waste combustion
gases to heat the incoming combustion air.
A third furnace used in the steel foundry is the induction
furnace. Induction furnaces are vertical refractory lined cylinders
4/81 Metallurgical Industry 7.13-1
-------
RAW MATERIALS
UNLOADING, STORAGE,
TRANSFER
FLUX
METALLICS
CARBON SOURCES
SAND
BINDER
FUGITIVE
DUST
r^HYDROCARBONS
SCRAP
PREPARATION
1 FUMES AND-*-
FUGITIVE
DUST
SAND
AND SMOKE
-+-FURNANCE
VENT
FUGITIVE
DUST
I
FURNANCE
ELECTRIC ARC
INDUCTION
OTHER
i
-FUGITIVE FUMES
AND DUST
TAPPING,
TREATING
,--^FUGITIVE FUMES
MOLD POURING,
COOLING
AND DUST
OVEN VENT
CASTING
SHAKEOUT
^-FUGITIVE
DUST
COOLING
h »> FUMES AND
FUGITIVE
DUST
CLEANING,
FINISHING
-» FUGITIVE
DUST
SHIPPING
Figure 7.13-1. Typical flow diagram of a steel foundry.
7.13-2
EIIISSION F^.CTOP.S
4/81
-------
surrounded by electrical coils energized with alternating current.
The resulting fluctuating magnetic field heats the metal. Induction
furnaces are kept closed except when charging, skimming and tapping.
The molten metal is tapped by tilting and pouring through a hole in
the side. Induction furnaces are also used with other furnaces, to
hold and superheat a charge melted and refined in the other furnaces.
A very small fraction of the secondary steel industry also uses
crucible and pneumatic converter furnaces.
The basic melting process operations are 1) furnace charging,
in which metal, scrap, alloys, carbon, and flux are added to the
furnace, 2) melting, during which the furnace remains closed,
3) backcharging, which is the addition of more metal and possibly
alloys, 4) refining, during which the carbon content is adjusted,
5) oxygen lancing, which is injecting oxygen into the molten steel
to dislodge slag and to adjust the chemistry of the metal, 6) slag
removal, and 7) tapping the molten metal into a ladle or directly
into molds.
Mold and Core Production - Cores are forms used to make the internal
voids in castings, and molds are forms used to shape the casting
exterior. Cores are made of sand with organic binders, molded into
a core and baked in an oven. Molds are made of wet sand with clay
and organic additives, dried with hot air. Increasingly, coal
setting binders are being used in both core and mold production.
Used sand from castings shakeout operations is recycled to the sand
preparation area, where it is cleaned, screened and reused.
Casting and Finishing - When the melting process is complete, the
molten metal is tapped and poured into a ladle. At this time, the
molten metal may be treated by adding alloys and/or other chemicals.
The treated metal is then poured into molds and is allowed partially
to cool under carefully controlled conditions. Molten metal may be
poured directly from the furnace to the mold.
When partially cooled, the castings are placed on a vibrating
grid, and the sand of the mold and core are shaken away from the
casting. The sand is recycled to the mold manufacturing process,
and the casting is allowed to cool further.
In the cleaning and finishing process, burrs, risers and gates
are broken or ground off to match the contour of the casting.
Afterward, the castings are usually shot blasted to remove remaining
mold sand and scale.
7.13.2 Emissions and Controls
Emissions from the raw materials handling operations are
fugitive particulates generated from receiving, unloading, storage
and conveying all raw materials for the foundry. These emissions
are controlled by enclosing the major emission points and routing
the air from the enclosures through fabric filters.
4/81 Metallurgical Industry 7.13-3
-------
Emissions from scrap preparation consist of hydrocarbons if
solvent degreasing is used, and consist of smoke, organics and
carbon monoxide if heating is used. Catalytic incinerators and
afterburners of approximately 95 percent control efficiency for
carbon monoxide and organics can be applied to these sources.
Emissions from melting furnaces are particulates, carbon
monoxide, organics, sulfur dioxide, nitrogen oxides, and small
quantities of chlorides and fluorides. The particulates,, chlorides
and fluorides are generated by the flux, the carbon additives, and
dirt and scale on the scrap charge. Organics on the scrap and the
carbon additives effect CO emissions. The highest concentrations
of furnace emissions occur during charging, backcharging, alloying,
oxygen lancing, slag removal, and tapping operations, when the
furnace lids and doors are opened. Characteristically, these
emissions have escaped into the furnace building and have been
vented through roof vents. Controls for emissions during the
melting and refining operations focus on venting the furnace gases
and fumes directly to an emission collection duct and control
system. Controls for fugitive furnace emissions involve either the
use of building roof hoods or of special hoods near the furnace
doors, to collect emissions and route them to emission control
systems. Emission control systems commonly used to control partic-
ulate emissions from electric arc and induction furnaces are bag
filters, cyclones and venturi scrubbers. The capture efficiencies
of the collection systems, presented in Table 7.13-1, range from
80 to 100 percent. Usually, induction furnaces are uncontrolled.
The major pollutants from mold and core production are
particulates from sand reclaiming, sand preparation, sand mixing
with binders and additives, and mold and core forming. There are
volatile organics (VOC), CO and particulate emissions from core
baking, and VOC emissions from mold drying. Bag filters and high
energy scrubbers can be used to control particulates from mold and
core production. Afterburners and catalytic incinerators can be
used to control VOC and CO emissions.
In the casting operations, large quantities of particulates
can be generated in the steps prior to pouring. Emissions from
pouring consist of fumes, CO, VOC, and particulates from the mold
and core materials when contacted by the molten steel. As the mold
cools, emissions continue. A significant quantity of particulate
emissions is also generated during the casting shakeout operation.
The particulate emissions from the shakeout operations can be
controlled by either high efficiency cyclones or bag filters.
Emissions from pouring are usually uncontrolled.
Emissions from finishing operations consist of large particulates
from the removal of burrs, risers and gates, and during shot blasting.
Particulates from finishing operations typically are large and are
generally controlled by cyclones.
7.13-4 EMISSION FACTORS 4/81
-------
TABLE 7.13-1. EMISSION FACTORS FOR STEEL FOUNDRIES
EMISSION FACTOR RATING: A
Nitrogen
Particulates3 oxides
Process kg/Mg Ib/ton kg/Mg Ib/ton
Melting
Electric arcb'c 6.5 (2 to 20) 13 (4 to 40) 0.1 0.2
Open hearthd'e 5.5 (1 to 10) 11 (2 to 20) 0.005 0.01
f B
Open hearth oxygen lanced '& 5 (4 to 5.5) 10 (8 to 11)
Electric induction 0.05 0.1
a
Expressed as units per unit weight of metal processed. If the scrap metal
is very dirty or oily, or if increased oxygen lancing is employed, the
.emission factor should be chosen from the high side of the factor range.
Electrostatic precipitator, 92 - 98% control efficiency; baghouse
(fabric filter), 98 - 99% control efficiency; venturi scrubber, 94 - 98%
control efficiency.
,References 2 - 10.
Electrostatic precipitator, 95 - 98.5% control efficiency; baghouse, 99.9%
control efficiency; venturi scrubber, 96 - 99% control efficiency.
^References 2, 11 - 13.
Electrostatic precipitator, 95 - 98% control efficiency; baghouse, 99% control
efficiency; venturi scrubber, 95 - 98% control efficiency.
^References 6 and 14.
Usually not controlled.
Emission factors for melting furnaces in the steel foundry are
presented in Table 7.13-1.
Although no emission factors are available for nonfurnace
emission sources in steel foundries, they are very similar to those
in iron foundries. Nonfurnace emission factors and particle size
distributions for iron foundry emission sources are presented in
Section 7.10, Gray Iron Foundries.
References for Section 7.13
1. Paul F. Fennelly and Peter D. Spawn, Air Pollutant Control
Techniques for Electric Arc Furnaces in the Iron and Steel
Foundry Industry, EPA-450/2-78-024, U.S. Environmental
Protection Agency, Research Triangle Park, NC, June 1978.
4/81 Metallurgical Industry 7.13-5
-------
2. J.J. Schueneman, et al., Air Pollution Aspects of the Iron and
Steel Industry, National Center for Air Pollution Control,
Cincinnati, OH, June 1963.
3. Foundry Air Pollution Control Manual, 2nd Ed., Foundry Air
Pollution Control Committee, Des Plaines, II, 1967.
4. R.S. Coulter, "Smoke, Dust, Fumes Closely Controlled in Electric
Furnaces", Iron Age, 173:107-110, January 14, 1954.
5. Air Pollution Aspects of the Iron and Steel Industry,, p. 109.
6. J.M. Kane and R.V. Sloan, "Fume Control Electric Melting
Furnaces", American Foundryman, 18:33-34, November 1950.
7. Air Pollution Aspects of the Iron and Steel Industry, p. 109.
8. C.A. Faist, "Electric Furnace Steel", Proceedings of the
American Institute of Mining and Metallurgical Engineers,
_U: 160-161, 1953.
9. Air Pollution Aspects of the Iron and Steel Industry,, p. 109.
10. I.H. Douglas, "Direct Fume Extraction and Collection Applied
to a Fifteen Ton Arc Furnace", Special Report on Fume Arrestment,
Iron and Steel Institute, 1964, pp. 144, 149.
11. Inventory of Air Contaminant Emissions, New York State Air
Pollution Control Board, Table XI, pp. 14-19. Date unknown.
12. A.C. Elliot and A.J. Freniere, "Metallurgical Dust Collection
in Open Hearth and Sinter Plant", Canadian Mining and Metal-
lurgical Bulletin, _55_(606) : 724-732, October 1962.
13. C.L. Hemeon, "Air Pollution Problems of the Steel Industry",
JAPCA, _1£(3):208-218, March I960.
14. D.W. Coy, Unpublished data, Resources Research, Incorporated,
Reston, VA.
7.13-6 EMISSION FACTORS 4/81
-------
7.14 SECONDARY ZINC PROCESSING
1 2
7.14.1 Process Description '
The secondary zinc industry processes obsolete and scrap
materials to recover zinc as slabs, dust and zinc oxide. Pro-
cessing involves three operations, scrap pretreatment, melting and
refining. Processes typically used in each operation are shown in
Figure 7.14-1. Molten product zinc may be used in zinc galvanizing.
Scrap Pretreatment - Pretreatment is the partial removal of metal
and other contaminants from scrap containing zinc. Sweating
separates zinc from high melting metals and contaminants by melting
the zinc in kettle, rotary, reverberatory, muffle or electric
resistance furnaces. The product zinc then is usually directly
used in melting, refining or alloying processes. The high melting
residue is periodically raked from the furnace and further processed
to recover zinc values. These residues may be processed by crushing/
screening to recover impure zinc or by sodium carbonate leaching to
produce zinc oxide.
In crushing/screening, zinc bearing residues are pulverized or
crushed to break the physical bonds between metallic zinc and
contaminants. The impure zinc is then separated in a screening or
pneumatic classification step.
In sodium carbonate leaching, the zinc bearing residues are
converted to zinc oxide, which can be reduced to zinc metal. They
are crushed and washed to leach out zinc from contaminants. The
aqueous stream is then treated with sodium carbonate, precipitating
zinc as the hydroxide or carbonate. The precipitate is then dried
and calcined to convert zinc hydroxide into crude, zinc oxide. The
ZnO product is usually refined to zinc at primary zinc smelters.
Melting - Zinc is melted at 425-590°C (800-1100°F) in kettle,
crucible, reverberatory and electric induction furnaces. Zinc to
be melted may be in the form of ingots, reject castings, flashing
or scrap. Ingots, rejects and heavy scrap are generally melted
first, to provide a molten bath to which light scrap and flashing
are added. Before pouring, a flux is added and the batch agitated
to separate the dross accumulating during the melting operation.
The flux floats the dross and conditions it so it can be skimmed
from the surface. After skimming, the melt can be poured into
molds or ladles.
Refining/Alloying - Additional processing steps may involve alloying,
distillation, distillation and oxidation, or reduction. Alloying
produces mainly zinc alloys from pretreated scrap. Often the
alloying operation is combined with sweating or melting.
Distillation retorts and furnaces are used to reclaim zinc
from alloys or to refine crude zinc. Retort distillation is the
4/81 Metallurgical Industry 7.14-1
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4/81
-------
TABLE 7.14-1.
UNCONTROLLED PARTICULATE EMISSION FACTORS
FOR SECONDARY ZINC SMELTING3
EMISSION FACTOR RATING: C
Emissions
Operation
Reverberatory sweating
clean metallic scrap
general metallic scrap
residual scrap
Rotary sweating
Muffle sweating0
Kettle sweating
clean metallic scrap
general metallic scrap
residual scrap
Electric resistance sweating0
Crushing/ screening
Sodium carbonate leaching
crushing/ screening0
calcining^
Kettle (pot) melting
Crucible melting
Reverberatory melting
Electric induction melting
Alloying
Retort and muffle distillation
pouring0
casting ,
muffle distillation
Graphite rod distillation0'6
Retort distillation/oxidation
Muffle distillation/oxidation
Retort reduction
Galvanizing
kg/Mg
Negligible
6.5
16
5.5-12.5
5.4-16
Negligible
5.5
12.5
<5
0.5-3.8
0.5-3.8
44.5
0.05
DNA
DNA
DNA
DNA
0.2-0.4
0.1-0.2
22.5
Negligible
10-20
10-20
23.5
2.5
Ib/ton
Negligible
13
32
11-25
10.8-32
Negligible
11
25
<10
1.0-7.5
1.0-7.5
89
0.1
DNA
DNA
DNA
DNA
0.4-0.8
0.2-0.4
45
Negligible
20-40
20-40
47
5
Expressed as units per unit weight of feed material processed for
crushing/screening, skimming/residues processed; for kettle (pot)
melting and retort and muffle distillation operations, metal
product. Galvanizing factor expressed in units per unit weight
.of zinc used. DNA: Data not available.
Reference 3.
.Reference 4.
References 5-7.
^Reference 1.
Reference 4. Factor units per unit weight of ZnO produced. The
product zinc oxide dust is totally carried over in the exhaust gas
from the furnace and is recovered with 98-99% efficiency.
4/81
Metallurgical Industry
7.14-3
-------
vaporization at 980-1250°C (1800-2280°F) of elemental zinc with its
subsequent condensation as zinc dust or liquid zinc. Rapid cooling
of the vapor stream below the zinc melting point produces zinc
dust, which can be removed from the condenser and packaged. If
slab zinc is the desired product, the vapors are condensed slowly
at a higher temperature. The resultant melt is cast into ingots or
slabs. Muffle distillation furnaces produce principally zinc
ingots, and graphite rod resistance distillation produces zinc
dust.
Retort and muffle furnace distillation and oxidation processes
produce zinc oxide dust. These processes are similar to distillation
through the vaporization step. In contrast, for distillation/oxi-
dation, the condenser is omitted, and the zinc vapor is discharged
directly into an air stream leading to a refractory lined combustion
chamber. Excess air is added to complete oxidation and to cool the
product. The zinc oxide product is usually collected in a baghouse.
In retort reduction, zinc metal is produced by the reaction of
carbon monoxide and zinc oxide to yield zinc and carbon dioxide.
Carbon monoxide is supplied by the partial oxidation of the coke.
The zinc is recovered by condensation.
Zinc Galvanizing - Zinc galvanizing is the coating of clean oxide
free iron or steel with a thin layer of zinc by immersion in molten
zinc. The galvanizing occurs in a vat or in dip tanks containing
molten zinc and cover flux.
1 2
7.14.2 Emissions and Controls '
Factors for uncontrolled point source and fugitive particulate
emissions are tabulated in Tables 7.14-1 and 7.14-2 respectively.
Emissions from sweating and melting operations consist
principally of particulates, zinc fumes, other volatile metals,
flux fumes and smoke generated by the incomplete combustion of
grease, rubber and plastics in the zinc bearing feed material.
Zinc fumes are negligible at low furnace temperatures, for they
have a low vapor pressure even at 480°C (900°F). With elevated
temperatures, however, heavy fuming can result. Flux emissions are
minimized by the use of a nonfuming flux. Substantial emissions
may arise from incomplete combustion of carbonaceous material in
the zinc scrap. These contaminants are usually controlled by
afterburners. Further emissions are the products of combustion of
the furnace fuel. Since the furnace fuel is usually natural gas,
these emissions are minor. In reverberatory furnaces, the products
of fuel combustion are emitted with the other emissions. Other
furnaces emit the fuel combustion products as a separate emission
stream.
Particulates from sweating and melting are mainly hydrated
and ZnO, with small amounts of carbonaceous material. Chemical
7.14-4 EMISSION FACTORS 4/81
-------
TABLE 7.14-2. FUGITIVE PARTICIPATE UNCONTROLLED EMISSION
FACTORS FOR SECONDARY ZINC SMELTING
EMISSION FACTOR RATING: E
Particulate
Operation
Reverberatory sweating
Rotary sweating
Muffle sweating
Kettle (pot) sweating
Electric resistance sweating
Crushing/screening
Sodium carbonate leaching
Kettle (pot) melting furnace
Crucible melting furnace
Reverberatory melting furnace
Electric induction melting
Alloying retort distillation
Retort and muffle distillation
Casting
Graphite rod distillation
Retort distillation/oxidation
Muffle distillation/oxidation
Retort reduction
kg/Mg
0.63
0.45
0.54
0.28
0.25
2.13
DNA
0.0025
0.0025
0.0025
0.0025
DNA
1.18
0.0075
DNA
DNA
DNA
DNA
Ib/ton
1.30
0.90
1.07
0.56
0.50
4.25
DNA
0.005
0.005
0.005
0.005
DNA
2.36
0.015
DNA
DNA
DNA
DNA
Reference 8. Expressed as units per end product, except factors
for crushing/screening and electric resistance furnaces, which are
expressed as units per unit of scrap processed. DNA: Data not
.available.
Estimate based on stack emission factor given in Reference 1,
assuming fugitive emissions to be equal to 5% of stack emissions.
Reference 1. Average of reported emission factors.
Engineering judgement, assuming fugitive emissions from crucible
melting furnace to be equal to fugitive emissions from kettle
(pot) melting furnace.
4/81
Metallurgical Industry
7.14-5
-------
analyses of particulate emissions from kettle sweat are shown in
Table 7.14-3.
TABLE 7.14-3. COMPOSITION OF PARTICULATE EMISSIONS
FROM KETTLE SWEAT PROCESSING3
Component Percent
ZnCl2 14.5 - 15.3
ZnO 46.9 - 50.0
NH.C1 1.1-1.4
4
A1203 1.0 - 2.7
Fe203 0.3 - 0.6
PbO 0.2
H20 (in ZnCl2 4H20) 7.7 - 8.1
Oxide of Mg, Sn, Ni, Si, Ca, Na 2.0
Carbonaceous material 10.0
Moisture (deliquescent) 5.2 - 10.2
Reference 3.
These particulates also contain Cu, Cd, Mn and Cr. Another
analysis showed the following composition: 4 percent ZnCl2, 77 percent
ZnO, 4 percent H20, 4 percent metal chlorides and 10 percent carbona-
ceous matter.1^ These particulates vary widely in size. Particulates
from kettle sweating of residual zinc scrap had the following size
distributions :
60% 0 -
17% 11 - 20n
23%
Particulates from kettle sweating of metallic scrap had mean particle
size distributions ranging from Dp5Q = 1.1/n to Dp5Q = 1.6|i. Emissions
from a reverberatory sweat furnace had an approximate Dp^Q = l|i.
Baghouses are most commonly used to recover particulate emissions
from sweating and melting. In one application on a muffle sweating
7.14-6 EMISSION FACTORS 4/81
-------
furnace, a cyclone and baghouse achieved particulate recovery
efficiencies in excess of 99.7 percent. In another application on
a reverberatory sweating furnace, a baghouse removed 96.3 percent
of the particulates, reducing the dust loading from 0.513 g/Nm-> to
0.02 g/Nm^.2 Baghouses show similar efficiencies in removing
particulates from exhaust gases of melting furnaces.
Crushing and screening operations are also sources of dust
emissions. These particulates are composed of Zn, Al, Cu, Fe, Pb,
Cd, Sn and Cr, and they can be recovered from hooded exhausts by
baghouses.
The sodium carbonate leaching process produces particulate
emissions of ZnO dust during the calcining operation. This dust
can be recovered in baghouses, although ZnCl2 in the dust may cause
plugging problems.
Emissions from refining operations are mainly metallic fumes.
These fume and dust particles are quite small, with sizes ranging
from 0.05 - lu. Distillation/oxidation operations emit their
entire ZnO product in the exhaust gas. The ZnO has a very small
particle size (0.03 to 0.5[_i) and is recovered in baghouses with
typical collection efficiencies of 98-99 percent.
Some emissions of zinc oxide occur during galvanizing, but
these emissions are small because of the bath flux cover and the
relatively low temperature maintained in the bath.
Data describing the particle size distribution of fugitive
emissions are unavailable. These emissions are probably similar in
size to stack emissions.
References for Section 7.14
1. William M. Coltharp, et al., Multimedia Environmental Assessment
of the Secondary Nonferrous Metal Industry, Draft Final Report,
2 vols., EPA Contract No. 68-02-1319, Radian Corporation,
Austin, TX, June 1976.
2. John A. Danielson, Air Pollution Engineering Manual, 2nd
Edition, AP-42, U.S. Environmental Protection Agency, Research
Triangle Park, NC, 1973. Out of Print.
3. W. Herring, Secondary Zinc Industry Emission Control Problem
Definition Study (Part 1), APTD-0706, U.S. Environmental
Protection Agency, Research Triangle Park, NC, May 1971.
4. H. Nack, et al., Development of an Approach to Identification
of Emerging Technology and Demonstration Opportunities, EPA-650/
2-74-048, U.S. Environmental Protection Agency, Research
Triangle Park, NC, May 1974.
4/81 Metallurgical Industry 7.14-7
-------
5. G.L. Allen, et al., Control of_ Metallurgical and Mineral Dusts
and Fumes in Los Angeles County, Number 7627, U.S. Department
of the Interior, Washington, DC, April 1952.
6. Restricting Dust and Sulfur Dioxide Emissions from Lead Smelters,
translated from German, VDI Number 2285, U.S. Department of
Health, Education and Welfare, Washington, DC, September 1961.
7. W.F. Hammond, Data on Nonferrous Metallurgical Operations, Los
Angeles County Air Pollution Control District, Los Angeles,
CA, November 1966.
8. Assessment of Fugitive Particulate Emission Factors for
Industrial Processes, EPA-450/3-78-107, U.S. Environmental
Protection Agency, Research Triangle Park, NC, September 1978.
7.14-8 EMISSION FACTORS 4/81
-------
8. MINERAL PRODUCTS INDUSTRY
This section involves the processing and production of various minerals. Mineral processing is characterized
by particulate emissions in the form of dust. Frequently, as in the case of crushing and screening, this dust is
identical to the material being handled. Emissions also occur through handling and storing the finished product
because this material is often dry and fine. Particulate emissions from some of the processes such as quarrying,
yard storage, and dust from transport are difficult to control. Most of the emissions from the manufacturing pro-
cesses discussed in this section, however, can be reduced by conventional particulate control equipment such as
cyclones, scrubbers, and fabric filters. Because of the wide variety in processing equipment and final product,
emissions cover a wide range; however, average emission factors have been presented for general use.
4/81 Mineral Products Industry 8.0-1
-------
-------
8.1 ASPHALTIC CONCRETE PLANTS
8.1.1 General
Asphaltic concrete (asphaltic hot mix) is a paving material
which consists of a combination of graded aggregate that is dried,
heated and evenly coated with hot asphalt cement.
Asphalt hot mix is produced by mixing hot, dry aggregate with
hot liquid asphalt cement, in batch or continuous processes. Since
different applications require different aggregate size distribu-
tions, the aggregate is segregated by size and is proportioned into
the mix as required. In 1975, about 90 percent of total U.S.
production was conventional batch process, and most of the remainder
was continuous batch. The dryer drum process, another method of
hot mix asphalt production, in which wet aggregate is dried and
mixed with hot liquid asphalt cement simultaneously in a dryer,
comprised less than 3 percent of the total, but most new construc-
tion favors this design. Plants may be either permanent or portable.
Conventional Plants - Conventional plants produce finished asphaltLc
concrete through either batch (Figure 8.1-1) or continuous
(Figure 8.1-2) aggregate mixing operations. Raw aggregate is
normally stockpiled near the plant, at a location where the moisture
content will stabilize to between 3 and 5 percent by weight.
As processing for either type of operation begins, the aggregate
is hauled from the storage piles and is placed in the appropriate
hoppers of the cold feed unit. The material is metered from the
hoppers onto a conveyor belt and is transported into a gas or oil
fired rotary dryer. Because a substantial portion of the heat is
transferred by radiation, dryers are equipped with flights designed
to tumble the aggregate to promote drying.
As it leaves the dryer, the hot material drops into a bucket
elevator and is transferred to a set of vibrating screens, where it
is classified into as.many as four different grades (sizes). The
classified hot materials then enter the mixing operation.
In a batch plant, the classified aggregate drops into one of
four large bins. The operator controls the aggregate size distri-
bution by opening individual bins and allowing the classified
aggregate to drop into a weigh hopper until the desired weight is
obtained. After all the material is weighed, the sized aggregates
are dropped into a mixer and mixed dry for about 30 seconds. The
asphalt, a solid at ambient temperatures, is pumped from heated
storage tanks, weighed and injected into the mixer. The hot mix is
then dropped into a truck and hauled to the job site.
In a continuous plant, the classified aggregate drops into a
set of small bins which collect and meter the classified aggregate
to the mixer. From the hot bins, the aggregate is metered through
4/81 Mineral Products Industry 8.1-1
-------
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Mineral Products Industry
8.1-3
-------
a set of feeder conveyors to another bucket elevator and into the
mixer. Asphalt is metered through the inlet end of the mixer, and
retention time is controlled by an adjustable dam at the end of the
mixer. The mix flows out of the mixer into a hopper from which
trucks are loaded.
Dryer Drum Plants - The dryer drum process simplifies the conven-
tional process by using proportioning feed controls in place of hot
aggregate storage bins, vibrating screens and the mixer.
Figure 8.1-3 is a diagram of the dryer drum process. Both
aggregate and asphalt are introduced near the flame end of the
revolving drum. A variable flow asphalt pump is linked electron-
ically to the aggregate belt scales to control mix specifications.
Dryer drum plants generally use parallel flow design for hot
burner gases and aggregate flow. Parallel flow has the advantage
of giving the mixture a longer time to coat and to collect dust in
the mix, thereby reducing particulate emissions to the atmosphere.
The amount of particulates generated within the dryer in this
process is lower than that generated within conventional dryers,
but because asphalt is heated to high temperatures for a long
period of time, organic emissions are greater.
The mix is discharged from the revolving dryer drum into surge
bins or storage silos.
22
Recycle Process for Drum Mix - Asphalt injected directly into the
dryer in the drum mix process is uniquely suited for the new, fast
developing technology of recycling asphalt pavement. Many drum mix
plants are now sold with a "recycle kit", which allows the plant to
be converted to process blends of virgin and recycled material.
In a recycling process, salvaged asphalt pavement (or base
material) that has been crushed and screened is introduced into the
dryer drum at a point somewhere downstream of the virgin aggregate
inlet. The amount of recycled pavement that can be successfully
processed has not yet been determined, but eventually, as the tech-
nology is developed, the blends may approach 100 percent recycled
material. Current blends range from about 20 percent to a maximum
of 50 percent recycled material.
The advantages of the recycling process are that blended
recycled material and virgin aggregate are generally less expensive
than 100 percent virgin aggregate, liquid asphalt requirements are
less due to residual asphalt in the recycled material, and the
recycled material requires less drying than the virgin aggregate.
The chief problem with recycling is opacity standards, because of
emissions of blue smoke (an aerosol of submicron organic droplets
volatilized from the asphalt and subsequently condensed before
exiting the stack). However, current recycle plant designs have
8.1-4 EMISSION FACTORS 4/81
-------
c
JO
Q.
*J
CO
Q.
E
D
a
a>
0)
a
re
0)
.c
CO
oo
4/81
Mineral Products Industry
8.1-5
-------
reduced blue smoke emissions greatly by preventing direct contact
of flame and liquid asphalt as it is injected.
8.1.2 Emissions and Controls
Emission points at batch, continuous and drum dryer hot mix
asphalt plants numbered below refer to Figures 8.1-1, 2 and 3,
respectively.
Emissions from the various sources in an asphaltic concrete
plant are vented either through the dryer vent or the scavenger
vent. The dryer vent stream goes to the primary collector. The
outputs of the primary collector and the scavenger vent go to the
secondary collector, then to the stack (1) for release to the atmos-
phere. The scavenger vent carries releases from the hot aggregate
elevator (5), vibrating screens (5), hot aggregate storage bins
(5), weigh hopper and mixer (2). The dryer vent carries emissions
only from the dryer. In the dryer drum process, the screens, weigh
hopper and mixer are not in a separate tower. Dryer emissions in
conventional plants contain mineral fines and fuel combustion
products, and the mixer assembly (2) also emits materials from the
hot asphalt. In dryer drum plants, both types of emissions arise
in the drum.
Emissions from drum mix recycled asphalt plants are similar
to emissions from regular drum mix plants, except for greater vola-
tile organics due to direct flame volatilization of petroleum deriva-
tives contained in used asphalt. Control of liquid organic emissions
in the drum mix recycle process is by (1) introduction of recycled
material at the center of the drum or farther toward the discharge
end, coupled with a flight design that causes a dense curtain of
aggregate between the flame and the residual asphalt, (2) protection
of the material from the flame by a heat shield, or (3) insulation
of the recycled material from the combustion zone entirely by a
drum-within-a-drum arrangement in which virgin material is dried
and coated in the inner drum, recycled material is indirectly heated
in the annular space surrounding the inner drum, and the materials
are mixed at discharge of the inner drum.
Potential fugitive particulate emission sources from asphaltic
concrete plants include unloading of aggregate to storage bins (5),
conveying aggregate by elevators (5), and aggregate screening
operations (5). Another source of particulate emissions is the
mixer (2), which, although it is generally vented into the secondary
collector, is open to the atmosphere when a batch is loaded onto a
truck. This is an intermittent operation, and ambient conditions
(wind, etc.) are quite variable, so these emissions are best regarded
as fugitive. The open truck (4) can also be a source of fugitive
VOC emissions, as can the asphalt storage tanks (3), which may also
emit small amounts of polycyclics.
8.1-6 EMISSION FACTORS 4/81
-------
Thus, fugitive particulate emissions from hot mix asphalt plants
are mostly dust from aggregate storage, handling and transfer.
Stone dust may range from 0.1 ^m to more than 300 [im in diameter.
On the average, 5 percent of cold aggregate feed is <74 /zm (minus
200 mesh). Dust that may escape before reaching primary dust col-
lection generally is 50 to 70 percent <74 /im. Materials emitted
are given in Tables 8.1-1 and 8.1-4.
Emission factors for various materials emitted from the stack
are given in Table 8.1-1. With the exception of aldehydes, the
materials listed in this table are also emitted from the mixer,
but mixer concentrations are 5 to 100 fold smaller than stack con-
centrations, lasting only during the discharge of the mixer.
TABLE 8.1-1. EMISSION FACTORS FOR SELECTED MATERIALS FROM
AN ASPHALTIC CONCRETE PLANT STACK3
Material Emitted
Particulated ,
d e
Sulfur oxides (as SO ) '
Nitrogen oxides (as NO )
f
Volatile organic compounds
Carbon monoxide
f
Polycyclic organic material
Aldehydes
Formaldehyde
2-Methylpropanal
( isobuty raldehyde )
1-Butanal
(n-butyraldehyde )
3-Methylbutanal
(isovaleraldehyde)
Emission
Factor
Rating
B
C
D
D
D
D
D
D
D
D
D
Emission
g/Mg
137
146S
18
14
19
0.013
10
0.077
0.63
1.2
8.3
Factor0
Ib/ton
.274
.292S
.036
.20
.038
.000026
.020
.00015
.0013
.0024
.016
. Reference 16.
Particulates, carbon monoxide, polycyclics, trace metals and
hydrogen sulfide were observed in the mixer emissions at con-
centrations that were small relative to stack concentrations.
Expressed as g/Mg and Ib/ton of asphaltic concrete produced.
^lean of 400 plant survey source test results.
Reference 21. S = % sulfur in fuel. S02 may be attenuated more
fthat 50% by adsorption on alkaline aggregate.
Based on limited test data from the single asphaltic concrete
plant described in Table 8.1-2.
4/81
Mineral Products Industry
8.1-7
-------
Reference 16 reports mixer concentrations of SOX, NOX, VOC and
ozone as less than certain values, so they may not be present at
all, while participates, carbon monoxide, polycycllcs, trace metals
and hydrogen sulfide were observed at concentrations that were small
relative to stack amounts. Emissions from the mixer are thus best
treated as fugitive.
The materials listed in Table 8.1-1 are discussed below.
Factor ratings are listed for each material in the table. All emis-
sion factors are for controlled operation, based either on average
industry practice shown by survey or on actual results of testing
in a selected typical plant. The characteristics of this represen-
tative plant are given in Table 8.1-2.
TABLE 8.1-2. CHARACTERISTICS OF AN ASPHALTTC
CONCRETE PLANT SELECTED FOR SAMPLING3
Parameter
Plant Sampled
Plant type
Production rate,
Mg/hr (ton/hr)
Mixer capacity,
Mg (tons)
Primary collector
Secondary collector
Fuel
Release agent
Stack height, m (ft)
Conventional permanent
batch plant
160.3 ± 16%
(177 ± 16%)
3.6 (4.0)
Cyclone
Wet scrubber (venturi)
Oil
Fuel oil
15.85 (52)
Reference 16, Table 16.
The industrial survey showed that over 66 percent of operating
hot mix asphalt plants use fuel oil for combustion. Possible sulfur
oxide emissions from the stack were calculated assuming that all
sulfur in the fuel oil is oxidized to SOX. The amount of sulfur
oxides actually released through the stack may be attenuated by
water scrubbers or even by the aggregate itself, if limestone is
being dried. No. 2 fuel oil has an average sulfur content of
0.22 percent.
Emission factors for nitrogen oxides, nonmethane volatile
organics, carbon monoxide, polycyclic organic material and aldehydes
1.1-8
EMISSLON FACTORS
4/31
-------
were determined by sampling stack gas at the representative asphalt
hot mix plant.
The choice of applicable control equipment ranges from dry
mechanical collectors to scrubbers and fabric collectors. Attempts
to apply electrostatic precipitators have met with little success.
Practically all plants use primary dust collection equipment such
as large diameter cyclones, skimmers or settling chambers. These
chambers are often used as classifiers to return collected material
to the hot aggregate elevator combine it with the dryer aggregate
load. The primary collector effluent is ducted to a secondary
collection device because of high emission levels if vented to the
atmosphere.
TABLE 8.1-3. PARTICIPATE EMISSION FACTORS FOR
CONVENTIONAL HOT MIX ASPHALTIC PLANTS3
EMISSION FACTOR RATING: B
Emission Factor
Type of Control kg/Mg Ib/ton
c d
Uncontrolled '
Precleaner"
High efficiency cyclone
Spray tower
Baffle spray tower
Multiple centrifugal scrubber
Orifice scrubber
Venturi scrubber^
Baghouse*
22.5
7.5
0.85
0.20
0.15
0.035
0.02
0.02
0.01
45.0
15.0
1.7
0.4
0.3
0.07
(.007-. 138)
0.04
0.04
(.025-. 053)
0.02
(0. 07-. 036)
^References 1, 2, 5-10 and 14-16.
Expressed in terms of emissions per unit weight of asphalt
concrete produced.
Almost all plants have at least a cleaner following the
.rotary dryer.
Reference 16. These factors differ from those given in
Table 8.1-1 because they are for uncontrolled emissions and
are from an earlier survey.
6Reference 15. Average emission from a properly designed,
installed, operated and maintained scrubber, based on a
fstudy to develop New Source Performance Standards.
References 14 and 15.
g
References 14 and 15. Emissions from a properly designed,
installed, operated and maintained baghouse, based on a study
to develop New Source Performance Standards.
4/81 Mineral Products Industry 8.1-9
-------
Particulate emission factors for conventional asphaltic concrete
plants are presented in Table 8.1-3. Particle size distribution
information has not been included, because the particle size distri-
bution varies with the aggregate being used, the mix being made and
the type of plant operation. Potential fugitive particulate emis-
sion factors for conventional asphaltic concrete plants are shown
in Table 8.1-4.
Particulate emission factors for dryer drum plants are presented
in Table 8.1-5. (There are no data for other pollutants released
from the dryer drum hot mix process.) Particle size distribution
has not been included, because it varies with the aggregate used,
the mix made and the type of plant operation. Emission factors for
particulates in an uncontrolled plant can vary by a factor of 10,
depending upon the percent of fine particles in the aggregate.
References for Section 8.1
1. Asphaltic Concrete Plants Atmospheric Emissions Study,
EPA Contract No. 68-02-0076, Valentine, Fisher, and Tomlinson,
Seattle, WA, November 1971.
2. Guide for Air Pollution Control of Hot Mix Asphalt Plants,
Information Series 17, National Asphalt Pavement Association,
Riverdale, MD.
3. J.A. Danielson, "Control of Asphaltic Concrete Batching Plants
in Los Angeles County", JAPCA, ^0(2):29-33, 1960.
4. H.E. Friedrich, "Air Pollution Control Practices and Criteria
for Hot Mix Asphalt Paving Batch Plants", JAPCA, _19(12):424-8,
December 1969.
5. Air Pollution Engineering Manual, AP-40, U.S. Environmental
Protection Agency, Research Triangle Park, NC, 1973. Out of
Print.
6. G.L. Allen, et al., "Control of Metallurgical and Mineral Dust
and Fumes in Los Angeles County, California", Information
Circular 7627, U.S. Department of Interior, Washington, DC,
April 1952.
7. P.A. Kenline, Unpublished report on control of air pollutants
from chemical process industries, Robert A. Taft Engineering
Center, Cincinnati, OH, May 1959.
8. G. Sallee, Private communication on particulate pollutant study
between Midwest Research Institute and National Air Pollution
Control Administration, Durham, NC, June 1970.
8.1-10 EMISSEON FACTORS 4/81
-------
TABLE 8.1-4. POTENTIAL UNCONTROLLED FUGITIVE
PARTICIPATE EMISSION FACTORS FOR CONVENTIONAL
ASPHALT1C CONCRETE PLANTS
EMISSION FACTOR RATING: E
f-i
Particulates
Type of Operation kg/MgIb/ton
Unloading coarse and fine
aggregate to storage bins" 0.05 0.10
Cold and dried (and hot)
aggregate elevator'3 0.10 0.20
Q
Screening hot aggregate 0.013 0.026
^Expressed as units per unit weight of aggregate.
Reference 18. Assumed equal to similar sources.
Reference 19. Asssumed equal to similar crushed
granite processes.
TABLE 8.1-5. PARTICULATE EMISSION FACTORS
FOR DRYER DRUM HOT MIX ASPHALT PLANTS3
EMISSION FACTOR RATING: B
Type of Control
Uncontrolled
Cyclone or multicyclone
c
Low energy wet scrubber
Venturi scrubber
Emission
kg/Mg
2.45
0.34
0.04
0.02
Factor
Ib/ton
4.9
0.67
0.07
0.04
-Reference 11.
Expressed in terms of emissions per unit weight of
asphalt concrete produced. These factors differ
from those for conventional asphaltic concrete
plants because the aggregate contacts, and is coated
with, asphalt early in the dryer drum process.
Either stack sprays where water droplets are
injected into the exit stack, or a dynamic scrubber
that incorporates a wet fan.
4/81 Mineral Products Industry 8.1-11
-------
9. J.A. Danlelson, Unpublished test data from asphalt hatching
plants, Los Angeles County Air Pollution Control District,
Presented at Air Pollution Control Institute, University of
Southern California, Los Angeles, CA, November 1966.
10. M.E. Fogel et al., Comprehensive Economic Study of Air Pollution
Control Costs for Selected Industries and Selected Regions,
R-OU-455, U.S. Environmental Protection Agency, Research
Triangle Park, NC, February 1970.
11. Preliminary Evaluation of Air Pollution Aspects of the Drum
Mix Process, EPA-340/1-77-004, U.S. Environmental Protection
Agency, Research Triangle Park, NC, March 1976.
12. R.W. Beaty and B.M. Bunnell, "The Manufacture of Asphalt
Concrete Mixtures in the Dryer Drum", Presented at the Annual
Meeting of the Canadian Technical Asphalt Association, Quebec
City, Quebec, November 19-21, 1973.
13. J.S. Kinsey, An Evaluation of Control Systems and Mass Emission
Rates from Dryer Drum Hot Asphalt Plants, Colorado Air Pollution
Control Division, Denver, CO, December 1976.
14. Background Information for Proposed New Source Performance
Standards, APTD-1352A and B, U.S. Environmental Protection
Agency, Research Triangle Park, NC, June 1973.
15. Background Information for New Source Performance Standards,
EPA 450/2-74-003, U.S. Environmental Protection Agency, Research
Triangle Park, NC, February 1974.
16. Z.S. Kahn and T.W. Hughes, Source Assessment: Aspha11 Paving
Hot Mix, EPA Contract No. 68-02-1874, Monsanto Research
Corporation, Dayton, OH, July 1977.
17. V.P. Puzinauskas and L.W. Corbett, Report on Emissions from
Asphalt Hot Mixes, RR-75-1A, The Asphalt Institute,, College
Park, MD, May 1975.
18. Evaluation of Fugitive Dust from Mining, EPA Contract
No. 68-02-1321, Pedco Environmental Specialists, Inc., Cincinnati,
OH, June 1976.
19. J.A. Peters and P.K. Chalekode, "Assessment of Oper Sources",
Presented at the Third National Conference on Energy and the
Environment, College Corner, OH, October 1, 1975.
20. Illustration of Dryer Drum Hot Mix Asphalt Plant, Pacific
Environmental Services, Inc., Santa Monica, CA, 1978.
8.1-12 EMISSION FACTORS 4/81
-------
21. Herman H. Forsten, "Applications of Fabric Filters to Asphalt
Plants", Presented at the 71st Annual Meeting of the Air Pol-
lution Control Association, Houston, TX, June 1978.
22. Emission of Volatile Organic Compounds from Drum Mix Asphalt
Plants, EPA Contract No. 68-01-2585, JACA Corporation, Fort
Washington, PA, September 1980.
4/81 Mineral Products Industry 8.1-13
-------
-------
8.2 ASPHALT ROOFING
8.2.1 General1
The asphalt roofing industry manufactures asphalt saturated felt
rolls, shingles, roll roofing with mineral granules on the surface, and
smooth roll roofing that may contain a small amount of mineral dust or
mica on the surface. Most of these products are used in roof construc-
tion, with small quantities used in walls and other building applications.
8.2.2 Process Description
The manufacturing of asphalt felt, roofing, and shingles involves
the saturating and coating of felt with heated asphalt (saturant asphalt
and/or coating asphalt) by means of dipping and/or spraying. The process
can be divided into (1) asphalt storage, (2) asphalt blowing, (3) felt
saturation, (4) coating and (5) mineral surfacing. Glass fiber is
sometimes used in place of the paper felt, in which case the asphalt
saturation step is bypassed.
Preparation of the asphalt is an integral part of the production of
asphalt roofing. This preparation, called "blowing", involves the
oxidation of asphalt flux by bubbling air through liquid asphalt flux at
260°C (500°F) for 1 to 4.5 hours, depending on the desired characteristics
of the asphalt, such as softening point and penetration rate.2 A typical
plant will blow from four to six batches per 16 hour day, and the roofing
line will operate for 16 hours per day and 5 days per week. Blowing may
be done either in vertical tanks or in horizontal chambers. Inorganic
salts such as ferric chloride (FeCls) may be used as catalysts to achieve
desired properties and to increase the rate of reaction in the blowing
still, thus decreasing the time required for each blow.3 Air blowing of
asphalt may be conducted at oil refineries, asphalt processing plants,
and asphalt roofing plants. Figure 8.2-1 illustrates an asphalt blowing
operation.
Figure 8.2-2 shows a typical line for the manufacture of
asphalt-saturated felt, which consists of a paper feed roll, a dry looper
section, a saturator spray section (if used), a saturator dipping section,
steam-heated drying-in drums, a wet looper, water cooled rollers, a
finish floating looper, and a roll winder.
Organic felt may weigh from 25 to 55 pounds per 480 square feet (a
common unit in the paper industry), depending upon the intended product.
The felt is unrolled from the unwind stand into the dry looper, which
maintains a constant tension on the material. From the dry looper, the
felt may pass into the spray section of the saturator (not used in all
plants), where asphalt at 205° to 250°C (400° to 480°F) is sprayed onto
one side of the felt through several nozzles. In the saturator dip
section, the saturated felt is drawn over a series of rollers, with the
bottom rollers submerged in hot asphalt at 205° to 250°C (400° to 480°F).
4/81 Mineral Products Industry 8.2-1
-------
KNOCKOUT BOX
OR CYCLONE
WATER VAPOR, OIL
AND PARTICULATE
ASPHALT
FLUX -?
125"-150°F
400°-4700F
BLOWING
STILL
CONTAINING
ASPHALT
WATER VAPOR
PARTICULATE
TO
CONTROL
DEVICE
RECOVERED OIL
WATER
AIR
FUEL
ASPHALT HEATER
AIR BLOWER
BLOWN ASPHALT
Figure 8.2.-1. Air blowing of asphalt.3
At the next step, steam heated drying-in drums and the wet looper provide
the heat and time, respectively, for the asphalt to penetrate the felt.
The saturated felt then passes through water cooled rolls and onto the
finish floating looper, and then is rolled and cut on the roll winder to
product size. Two common weights of asphalt felt are 15 and 30 pounds
per 108 square feet (108 square feet of felt covers exactly 100 square
feet of roof).
A typical process for manufacturing asphalt shingles, mineral
surfaced rolls and smooth rolls is illustrated in Figure 8.2-3. This
line is similar to the felt line, except that following the wet looper are
a coater, a granule applicator, a press section, water cooled rollers, a
finish floating looper, and either a roll winder or a shingle cutter and
stacker. After leaving the wet looper, the saturated felt passes through
the coater. Filled asphalt coating at 180° to 205°C (355° to 400°F) is
released through a valve onto the felt just as it passes into the coater.1
Filled asphalt is prepared by mixing coating asphalt at 205°C (400°F) and
8.2-2
EMISSION FACTORS
4/81
-------
n
VENT TO CONTROL
EQUIPMENT
BURNER
A
,-- FIRED""
~ - HEATER
1 » \
VENT TO
CONTROL DEVICE
*
i r
SATURAHT
STORAGE
PUMP
PUBP
8.2-2. Schematic of line for manufacturing asphalt saturated felt.1
4/81
Mineral Products Industry
1.2-3
-------
i 1
VENT TO CONTROL
EQUIPMENT
ASPHALT
SATURATOR
VENT TO
CONTROL
EQUIPMENT
GRANULES
APPLICATOR SANO
APPLICATOR
VENT TO
CONTROL
EQUIPMENT
t
SATURANT
STORAGE
VENT 70
CONTROL
EQUIPMENT
ROLLS TO STORAGE
SHINGLE BUNDLES
TO STORAGE "
SHINGLE STACKER
8.2-3. Schematic of line for manufacturing asphalt shingles, mineral .surfaced rolls, and smooth
rolls.1
8.2-4
EMISSION FACTORS
4/81
-------
a mineral stabilizer (filler) in approximately equal proportions. The
filled asphalt is pumped to the coater. Sometimes the mineral stabilizer
is dried at about 120°C (250°F) in a dryer before mixing with the coating
asphalt. Heated squeeze rollers in the coater distribute the coating
evenly upon the felt surface, to form a thick base coating to which rock
granules, sand, talc, or mica can adhere. After leaving the coater, a
felt to be made into shingles or mineral surfaced rolls passes through
the granules applicator where granules are fed onto the hot, coated
surface. The granules are pressed into the coating as it passes through
squeeze rollers. Sand, talc or mica is applied to the back, or opposite,
side of the felt and is also pressed into the felt surface. Following
the application of the granules, the felt is cooled rapidly and is
transferred through the finish flowing looper to a roll winder or shingle
cutter.
8.2.3 Emissions and Controls
The atmospheric emissions from asphalt roofing manufacturing are:
1. gaseous and particulate organic compounds that include small
amounts of particulate polycyclic organic matter (PPOM),
2. emissions of small amounts of aldehydes, carbon monoxide and
sulfur dioxide, and
3. particulate emissions from mineral handling and storage.
The sources of the above pollutants are the asphalt blowing stills,
the saturator and coater, the asphalt storage tanks, and the mineral
handling and storage facilities. Emission factors from uncontrolled
blowing and saturating processes for particulate, carbon monoxide, and
volatile organic carbon as methane and nonmethane are summarized in
Table 8.2-1.
A common method to control emissions at asphalt roofing plants is
completely to enclose the saturator, wet looper and coater and then to
vent the emissions to one or more control devices (see Figures 8.2-2 and
8.2-3). Fugitive emissions from the saturator may pass through roof
vents and other openings in the building, if the saturator enclosure is
not properly installed and maintained. Control devices used in the
industry include afterburners, high velocity air filters, low voltage
electrostatic precipitators, and wet scrubbers. Blowing operations are
controlled by afterburners. Table 8.2-2 presents emission factors for
controlled blowing and saturating processes.
Particulate emissions associated with mineral handling and storage
operations are captured by enclosures, hoods or pickup pipes and are
controlled by using cyclones and/or fabric filters with removal
efficiencies of approximately 80-99 percent.
4/81 Mineral Products Industry 8.2-5
-------
TABLE 8.2-1.
EMISSION FACTORS FOR ASPHALT ROOFING MANUFACTURING
WITHOUT CONTROLS3
EMISSION FACTOR RATING:
PARTICULATE- A
OTHER- D
Carbon
Particulates
Operation
Asphalt blowing
Q
Saturant
Coating
kg/Mg
3.6
13.4
Ib/ton
7.2
26.7
monoxide
kg/Mg
0.14d
Ib/ton
0.27d
Volatile
organic compounds
methane nonmethane
kg/Mg Ib/ton kg/Mg Ib/ton
e e e e
0.94 1.88 0.93 1.86
Shingle
saturation
g
0.25
0.50 0.01 0.02 0.04 0.08 0.01 0.02
Shingle ,
saturation
1.57
3.14 0.13 0.25 0.11 0.22 0.02 0.03
.References 2 and 4.
Expressed as kg/Mg (Ib/ton) of asphalt processed.
,Saturant blow of 1.5 hours.
Reference 2. CO data for uncontrolled emissions from stills was not
obtained during latest test program.
6Species data not available for saturant blow. Total organics (as CH4) for
saturant blow are 0.73 kg/Mg (1.460 Ib/ton).
Coating blow of 4.5 hours.
Expressed as kg/Mg (Ib/ton) of 106.5 kg (235 lb) shingle produced. Data
.from dip saturators.
Data from spray/dip saturator.
NOTES: -Particulate polycyclic organic matter is about 0.3 % of
particulate for blowing stills and 0.1 % of particulate for saturators.
-Aldehyde emission measurements made during coating blows:
4.6x10"5 kg/Mg (9.2xlO~5 Ib/ton).
-Aldehyde emissions data taken from one saturator only, with
afterburner the control device: 0.004 kg/Mg (0.007 Ib/ton).
-Species data not obtained for uncontrolled VOC, assumed same
percentage methane/nonmethane as in controlled emissions.
8.2-6
EMISSION FACTORS
4/81
-------
TABLE 8.2-2. EMISSION FACTORS FOR ASPHALT ROOFING MANUFACTURING
WITH CONTROLS3
EMISSION FACTOR RATING: PARTICULATE- A
OTHER- D
Volatile
Carbon organic compounds
Particulates monoxide methane nonmethane
Operation kg/Mg
Asphalt blowing
Saturantc 0.25
Coating6 0.45
Shingle
saturation 0.03
Ib/ton kg/Mg Ib/ton kg/Mg Ib/ton kg/Mg Ib/ton
0.50 0.6 1.2 d d d d
0.89 4.4 8.8 0.05 0.10 0.05 0.09
0.06 0.45 0.898 0.08 0.15 0.01 0.02
, References 2 and 4.
Expressed as kg/Mg (Ib/ton) of asphalt processed.
,Saturant blow of 1.5 hours.
Species data not available for saturant blow. Total organics (as CH4) for
saturant blow are 0.015 kg/Mg (0.03 Ib/ton).
..Coating blow of 4.5 hours.
Expressed as kg/Mg (Ib/ton) of 106.5 kg (235 Ib) shingle produced
(averages of test data from four plants).
CO emissions data taken from one plant only, with afterburner the
control device. Temperature of afterburner not high enough to convert
CO to C02.
NOTE: Particulate polyclic organic matter is about 0.03 % of particulate
for blowing stills and about 1.1 % of particulate for saturators.
4/81
Mineral Products Industry
8.2-7
-------
In this industry, closed silos are used for mineral storage, so open
storage piles are not a problem. To protect the minerals from moisture
pickup, all conveyors that are outside the buildings are enclosed.
Fugitive mineral emissions may occur at the unloading point, depending on
the type of equipment used. The discharge from the conveyor to the silos
is controlled by either a cyclone or a fabric filter.
References for Section 8.2
1. John A. Danielson, Air Pollution Engineering Manual (2d Ed.), AP-40,
U.S. Environmental Protection Agency, Research Triangle Park, NC,
May 1973. Out of print.
2. Atmospheric Emissions from Asphalt Roofing Processes, EPA Contract
No. 68-02-1321, Pedco Environmental, Cincinnati, OH, October 1974.
3. L. W. Corbett, "Manufacture of Petroleum Asphalt", Bituminous
Materials: Asphalts, Tars, and Pitches, Vol. 2, Part 1, New York,
Interscience Publishers, 1965.
4. Background Information for Proposed Standards Asphalt Roofing
Manufacturing Industry, EPA 450/3-80-021a, U.S. Enviromental
Protection Agency, Research Triangle Park, NC, June 1980.
8.2-8 EMISSION FACTORS 4/81
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APPENDIX C
NEDS SOURCE CLASSIFICATION CODES
and
EMISSION FACTOR LISTING
Source Classification Codes (SCC), defined for use in the
National Emissions Data System (NEDS), represent individual processes
or functions logically associated with points of air pollutant
emissions. Related to each SCC are emission factors for the five
NEDS pollutants (particulates, sulfur oxides, nitrogen oxides,
hydrocarbons and carbon monoxide). These emission factors are used
in the calculation of emissions estimates in NEDS and, normally, are
the same as the emission factors appearing in AP-42.
Updated editions of the NEDS SCC and emission factor listing
appear in AEROS Volume V. Because of its availability, the listing
will no longer be carried in AP-42. The SCC listing that appeared
in Supplement 9 of AP-42 does not reflect changes and additions made
to the NEDS SCC file since then.
Individuals who wish to obtain copies of the most current NEDS
SCC listing may request the most recent version of AEROS Volume V
from:
Requests and Information Section
National Air Data Branch (MD-14)
U.S. Environmental Protection Agency
Research Triangle Park, NC 27711
Phone (919) 541-5694, (FTS) 629-5694
4/81 EMISSION FACTORS C-l
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APPENDIX E
COMPILATION OF LEAD EMISSION F \CTOKS
INTRODUCTION
Lead was not involved as a specific pollutant in the earlier editions and supplements of AP-42. Since
a National Ambient Air Quality Standard for lead has been issued, it has become necessary to determine
emission factors for lead, and these are given in Table E-l. The AP-42 Section number given in this table
for each process corresponds to the pertinant section in the body of the document.
Lead emission factors for combustion and evaporation from mobile sources require a totally different
treatment, and they are not included in this Appendix.
Table E-1. UNCONTROLLED LEAD EMISSION FACTORS
AP-42
Section
1.1
1.2
1.3
1.3
1 7
1.11
21
2.5
Process
Bituminous coal combustion
(all furnace types)
Anthracite coal combustion
(all furnace types)
Residual fuel oil combustion
(all boiler types)
Distillate fuel oil combustion
(all boiler types)
Lignite combustion
(all boiler types)
Waste oil combustion
Refuse incineration
(municipal incinerator)
Sewage sludge incineration
(wet scrubber controlled)
Multiple hearth
Fluidized bed
Emission
Metric
0 8 (L) kg/106 kg
(Average L
08 (L) kg/106 kg
(Average L
05(L) kg/103m3
(Average L
05 (L) kg/103m3
(Average L
5-6 kg/106 kg
9 (P) kg/m3
(Average P -
0.2 kg/MT chgd
.01-. 02 kg/MT chgd
.0005-.002 kg/MT chgd
factora-b
English
1 6 (L)lb/103 ton
= 8.3 ppm)
1.6 (L) lb/103ton
= 8 1 ppm)
42(L) lb/106gal
= 10 ppm)
4.2 (L) lb/106gal
= 0.1 ppm)
10-11 lb/103 tons
75 (P) lb/103 gal
1 0 percent)
0 4 Ib/ton chgd
02-.03 Ib/ton chgd
001-.003 Ib/ton
References
1,4-6
1,4-6
1,7
1,7
2
18,51,52
1,3,9-11
3,12
3,12
7/79
Appendix E
E-l
-------
Table E-1 (continued). UNCONTROLLED LEAD EMISSION FACTORS
AP-42
Section
5.22
7.2
7.3
7.4
7.4
7.5
Process
Lead alkyl production
Electrolytic process
Sodium-lead alloy process
Recovery furnace
Process vents, TEL
Process vents, TML
Sludge pits
Metallurgical coke
manufacturing
Primary copper smelting
Roasting
Smelting (reverberatory
furnace)
Converting
Ferroalloy production -
electric arc furnace (open)
Ferrosilicon (50%);FeSi
Silicon metal
Silico-manganese
Ferro-manganese (standard)
Ferrochrome-silicon
High carbon ferrochrome
Ferroalloy production -
blast furnace
Iron and steel production
Sintering
(windbox + vent
discharges)
Blast furnace
(for mixed charge)
Emission
Metric
0.5 kg/MT prod
28 kg/MT prod
2 kg/MT rood
75 kg/MT prod
0.6 kg/MT prod
.000 18 kg/MT
coal chgd
0.03 kg/MT cone
0.03 kg/MT cone
0.06 kg/MT cone
0.1 5 kg/MT prod
0.001 5 kg/MT prod
0.29 kg/MT prod
0.06 kg/MT prod
0.04 kg/MT prod
0.17 kg/MT prod
1.9 kg/MT prod
0.0067 kg/MT sinter
0.062 kg/MT Fe
factor3'13
English
1.0 Ib/ton prod
55 Ib/ton prod
4 Ib/ton prod
150 Ib/ton prod
1.2 Ib/ton prod
.00035 Ib/ton
coal chgd
0.05 Ib/ton cone
0.06 Ib/ton cone
0.12 Ib/ton cone
0.29 Ib/ton prod
0.0031 Ib/ton prod
0.57 Ib/ton prod
0.1 1 Ib/ton prod
0.08 Ib/ton prod
0.34 Ib/ton prod
3.7 Ib/ton prod
0.013 Ib/ton sinter
0.124 Ib/ton Fe
References
1,3,53
1 ,53,54
1
1
1
1,13,14
65
65
65
20
1,19
1,21
1,3
20
20
1,3
1,23,24
1,23
E-2
EMISSION FACTORS
4/81
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Table E-1 (continued). UNCONTROLLED LEAD EMISSION FACTORS
AP-42
Section
7.6
7.7
79
7.10
Process
Open hearth
Lancing
No lancing
Basic oxygen furnace (BOF)
Electric arc furnace
Lancing
No lancing
Primary lead smelting
Ore crushing and grinding
Sintering
Blast furnace
Dross reverberatory furnace
Zinc smelting
Ore unloading, storage,
transfer
Sintering
Horizontal retorts
Vertical retorts
Secondary copper smelting
and alloying
Reverberatory furnace
(high lead alloy 58% Pb)
Red and yellow brass
(15% Pb)
Other alloys (7% Pb)
Gray iron foundries
Cupola
Emission
Metric
0.07 kg/MT steel
0.035 kg/MT steel
0 1 kg/MT steel
0 11 kg/MT steel
0 09 kg/MT steel
015 kg/MT ore
42-170 kg/MT Pb prod
8.7-50 kg/MT Pb prod
1 3-3.5 kg/MT Pb prod
0.035-0.1 kg/MT ore
13.5-25 kg/MT ore
1 2 kg/MT ore
2-2.5 kg/MT ore
25 kg/MT prod
6.6 kg/MT prod
2.5 kg/MT prod
0.05-0 6 kg/MT prod
facto r3"
English
0.14 Ib/ton steel
0.07 Ib/ton steel
0 2 Ib/ton steel
0.22 Ib/ton steel
0 18 Ib/ton steel
0 3 Ib/ton ore
8 4-340 Ib/ton Pb
prod
175-100 Ib/ton Pb
prod
2,6-7.0 Ib/ton Pb
prod
0.07-0.2 Ib/ton ore
27-50 Ib/ton ore
2 4 Ib/ton ore
4-5 Ib/ton ore
50 Ib/ton prod
13.2 Ib/ton prod
5 Ib/ton prod
0 1-1.1 Ib/ton prod
References
1
1
1,23,25
1,28
1
29
1,21,22,
30-33
1,30,32,
33,35,36
1,18,30,
34,36
1
1,30,38
1,30,38
1,30,38
1,26,39-41
1,26,39-41
1,26,39-41
1,3,26,
42,43
10/80
Appendix E
E-3
-------
Table E-1 (continued). UNCONTROLLED LEAD EMISSION FACTORS
AP-42
Section
7.11
7.15
7.16
7.17
Process
Reverberatory furnace
Electric induction furnace
Secondary lead smelting
Reverberatory furnace
Blast cupola furnace
Refining kettles
Storage battery production
(total)
Grid casting
Lead oxide mill (baghouse
outlet)
Three-process operations0
Lead reclaim furnace
Small parts casting
Lead oxide and pigment
production
Barton pot (baghouse
outlet)
Calcining furnace
Red lead (baghouse outlet)
White lead (baghouse
outlet)
Chrome pigments
Miscellaneous lead products
Type metal production
Can soldering"
Cable covering
Emission
Metric
0.006-0.7 kg/MT prod
0.005- .05 kg/MT prod
17 kg/MT Pb prod
22 kg/MT Pb prod
0.1 kg/MT Pb prod
8 kg/103 batteries
0.4 kg/103 batteries
0.05 kg/103 batteries
6.6 kg/103 batteries
0.35 kg/103 batteries
0.05 kg/103 batteries
0.22 kg/MT prod
7 kg/MT prod
0.5 kg/MT prod
0.28 kg/MT prod
0.065 kg/MT prod
0. 13 kg/MT Pb proc
160 kg/106 baseboxes
prod
0.25 kg/MT proc
factora-b
English
0.012-0.14 Ib/ton
prod
0.009-0.1 Ib/ton
prod
34 Ib/ton Pb prod
44 Ib/ton Pb prod
0.21 Ib/ton Pb prod
17. 7 lb/103 batteries
0.9 lb/103 batteries
0.1 2 lb/103 batteries
14.6 lb/103 batteries
0.77 lb/103 batteries
0.10 lb/103 batteries
0.44 Ib/ton prod
14 Ib/ton prod
0.9 Ib/ton prod
0.55 Ib/ton prod
0.13 Ib/ton prod
0.25 Ib/ton Pb Proc
0.1 8 ton/106 base-
boxes prod
0.5 Ib/ton Pb proc
References
1
1
1,66
1,66
46
1,55-58
1,55-58
1,55-58
1,55-58
1,55-58
1,55-58
1,61,62
61
1,54
1.54
1.54
1,63
1
1,3,64
E-4
EMISSION FACTORS
4/81
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55. Screening Study To Develop Background Information and To Determine the Significance of Emissions from
the Lead/Acid Battery Industry, EPA Contract No. 68-02-0299, Vulcan-Cincinnati, Inc., Cincinnati. OH,
December 1972.
56. Confidential test data from a major battery manufacturer, July 1973.
57. Paniculate and Lead Emission Measurements from Lead Oxide Plants, EPA Contract No. 68-02-0226,
Monsanto Research Corp., Dayton, OH, August 1973.
58. Background Information in Support of the Development of Performance Standards for the Lead/Acid Bat-
tery Industry, EPA Contract No. 68-02-2085, PEDCo-Environmental Specialists, Inc., Cincinnati, OH,
December, 1976.
59. Communication with Mr. J. Patrick Ryan, Lead-Zinc Branch, Bureau of Mines, U.S. Department of the In-
terior, Washington, DC, September 1976.
60. B.C. Wixson and J.C. Jennett, "The New Lead Belt in the Forested Ozarks of Missouri", Environmental
Science and Technology, 9(13):\\ 28-1133, December 1975.
61. Emission Test No. 74-PBO-l, Office of Air Quality Planning and Standards, U.S. Environmental Protection
Agency, Research Triangle Park, NC, August 1973.
62. Private communication with Bureau of Mines, U.S. Department of the Interior, Washington, DC, 1975.
63. Atmospheric Emissions from Lead Typesetting Operations - Screening Study, EPA Contract No.
68-02-2085, PEDCo-Environmental Specialists, Inc., Cincinnati, OH, January 1976.
64. E.P. Shea, Emissions from Cable Covering Facility, EPA Contract No. 68-02-0228, Midwest Research In-
stitute, Kansas City, MO, June 1973.
65. D. Ringwald and T. Rooney, Copper Smelters: Emission Test Report - Lead Emissions, EPA-79-CUS-14,
U.S. Environmental Protection Agency, Research Triangle Park, NC, September 1979.
66. J.M. Zoller, et al, A Method of Characterization and Quantification of Fugitive Lead Emissions from Secon-
dary Lead Smelters, Ferroalloy Plants and Gray Iron Foundries (Revised), EPA-450/3-78-003 (Revised),
U.S. Environmental Protection Agency, Research Triangle Park, NC, August 1978.
4/81 Appendix E E-9
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TECHNICAL REPORT DATA
(Please read imtnit ttoni on the rcverst before completing;
1
4
7
9
12
15
1b
17
a.
IB
REPORT NiO |2
AP-42, Supplement 12 J^
T,TLt AND SUBTITLE Supplement U for
Compilation of Air Pollutant Emission Factors, AP-42
AUTHORIS)
Monitoring and Data Analysis Division
PERFORMING ORGANIZATION NAME AND ADDRESS
US Environmental Protection Agency
Office of Air, Noise and Radiation
Office of Air Quality Planning and Standarc
Research Triangle Par'.c, NC 27711
SPONSORING AGENCY NAME AND ADDRESS
SUPPLEMENTARY NOTES
EPA Editor: Whitmel M. Joyner
is
3 RECIPIENT S ACCESSION NO
5 REPORT DATE
April 1981
6. PERFORMING ORGANIZATION CODE
B. PERFORMING ORGANIZATION REPORT NO.
10 PROGRAM ELEMENT NO
11 CONTRACT/GRANT NO
13. TYPE OF REPORT AND PERIOD COVERED
14 SPONSORING AGENCY CODE
ABSTRACT
In this Supplement for AP-42, revised or updated emissions data are presented
for Dry Cleaning; Surface Coating; Storage of Organic Liquids; Solvent Degreasing;
Graphic Arts; Consumer /commercial Solvent Use; Sulfuric Acid; Beer Making; Ammonium
Sulfate; Primary Aluminum; Secondary Aluminum; Gray Iron Foundries; Steel Foundries;
Secondary Zinc; Asphaltic Concrete; Asphalt Roofing; NEDS Source Classification
Codes and Emission Factor Listing; and Table of Lead Emission Factors.
KEY WORDS AND DOCUMENT ANALYSIS
DESCRIPTORS
Fuel Combustion Source Classificatio
Emissions Codes
Emission Factors
Stationary Sources
Lead Emissions
-
nisrp'auTioN STATEMFHJ-.-
Unlimited
b IDENTIFIERS/OPEN ENDED TERMS c. COSATI 1-rclcl/Group
1
IS SEC'JHITV Ci-ASS f/Vlit i-/i>pcrt) 21 NO OFPAGFo
. _ . _ 208
20 SE-.CUR-TY CL'SS rtlitvnitei 2T- PRICE
FPA Form 2220-i ;Re< "i-77> PHE.VIOUS EDITION 's ou-OLETE
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