AP-42
SUPPLEMENT C
SEPTEMBER 1990
SUPPLEMENT C
TO
COMPILATION
OF
AIR POLLUTANT
EMISSION FACTORS
VOLUME I:
STATIONARY POINT
AND AREA SOURCES
-------
This report has been reviewed by the Office Of Air Quality Planning And Standards, U. S. Environmental
Protection Agency, and has been approved for publication. Any mention of trade names or commercial
products is not intended to constitute endorsement or recommendation for use.
AIM2
Volume I
Supplement C
n
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INSTRUCTIONS FOR INSERTING SUPPLEMENT C
INTOAP-42
Pp. iii and iv replace same. New Publications In Series.
Pp. v through viii replace same. New Contents.
Pp. ix through xv replace same. New Key Word Index.
Pp. 1.10-1 through 1.10-5 replace same. Major Revision.
Pp. 2.1-1 through 2.1-20 replace 2.1-1 through 2.1-10. Major Revision.
Pp. 2.5-1 through 2.5-13 replace 2.5-1 through 2.5-6. Major Revision.
Add pp. 4.2.2.13-1 through 4.2.2.13-9. New Section.
Add pp. 4.2.2.14-1 through 4.2.2.14-18. New Section.
Pp. 5.19-1 through 5.19-24 replace 5.19-1 and 2. Major Revision.
Pp. 7.6-5 and 6 replace same. Minor Revision.
Pp. 7.10-19 through 7.10-21 replace same. Minor Revision.
Pp. 10.1-5 and 6 replace same. Major Revision.
Pp. 11.1-7 through 11.1-12 replace 11.1-7 through 11.1-11. Major Revision.
Pp. 11.2.6-1 and 2 replace same. Minor Revision.
Pp. 11.2.7-1 through 11.2.7-15 replace same. Minor Revision.
Pp. 11.3-1 through 11.3-5 replace same. Editorial Change.
Pp. C.2-5 and 6 replace same. Minor Revision.
Pp. C.2-17 through C.2-19 replace C.2-17 and 18. Major Revision.
Add pp. D-l through D-8. New Appendix.
Add pp. E-l through E-8. New Appendix.
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PUBLICATIONS IN SERIES
Issue
COMPILATION OF AIR POLLUTANT EMISSION FACTORS (Fourth Edition)
SUPPLEMENT A
Introduction
Section 1.1
1.2
1.3
1.4
1.6
1.7
5.16
7.1
7.2
7.3
7.4
7.5
7.6
7.7
7.8
7.10
7.11
8.1
8.3
8.6
8.10
8.13
8.15
8.19.2
8.22
8.24
10.1
11.2.6
Appendix C.1
Appendix C.2
Date
9/85
10/86
Bituminous And Subbituminous Coal Combustion
Anthracite Coal Combustion
Fuel Oil Combustion
Natural Gas Combustion
Wood Waste Combustion In Boilers
Lignite Combustion
Sodium Carbonate
Primary Aluminum Production
Coke Production
Primary Copper Smelting
Ferroalloy Production
Iron And Steel Production
Primary Lead Smelting
Zinc Smelting
Secondary Aluminum Operations
Gray Iron Foundries
Secondary Lead Processing
Asphaltic Concrete Plants
Bricks And Related Clay Products
Portland Cement Manufacturing
Concrete Batching
Glass Manufacturing
Lime Manufacturing
Crushed Stone Processing
Taconite Ore Processing
Western Surface Coal Mining
Chemical Wood Pulping
Industrial Paved Roads
Particle Size Distribution Data And Sized Emission Factors
For Selected Sources
Generalized Particle Size Distributions
SUPPLEMENT B
Section 1.1
1.2
9/88
1.
1.
.10
,11
2.1
2.5
4.2
4.12
Bituminous And Subbituminous Coal Combustion
Anthracite Coal Combustion
Residential Wood Stoves
Waste Oil Combustion
Refuse Combustion
Sewage Sludge Incineration
Surface Coating
Polyester Resin Plastics Product Fabrication
111
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Section 5.15
6.4
8.15
8.19.2
11.1
11.2.1
11.2.3
• 11.2.6
11.2.7
Appendix C.3
Soap And Detergents
Grain Elevators And Processing Plants
Lime Manufacturing
Crushed Stone Processing
Wildfires And Prescribed Burning
Unpaved Roads
Aggregate Handling And Storage Piles
Industrial Paved Roads
Industrial Wind Erosion
Silt Analysis Procedures
SUPPLEMENT C
Section 1.10
2.1
2.5
4.2.2.13
4.2.2.14
5.19
7.6
7.10
10.1
11.1
11.2.6
11.2.7
11.3
Appendix C.2
Appendix D
Appendix E
9/90
Residential Wood Stoves
Refuse Combustion
Sewage Sludge -Incineration
Magnetic Tape Manufacturing Industry
Surface Coating Of Plastic Parts For Business Machines
Synthetic Fiber Manufacturing
Primary Lead Smelting
Gray Iron Foundries
Chemical Wood Pulping
Wildfires And Prescribed Burning
Industrial Paved Roads
Industrial Wind Erosion
Explosives Detonation
Generalized Particle Size Distributions
Procedures For Sampling Surface/Bulk Dust Loading
Procedures For Laboratory Analysis Of Surface/Bulk Dust
Loading Samples
iv
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CONTENTS
Page
INTRODUCTION 1
1. EXTERNAL COMBUSTION SOURCES 1.1-1
1.1 Bituminous Coal Combustion 1.1-1
1.2 Anthracite Coal Combustion 1.2-1
1.3 Fuel Oil Combustion 1.3-1
1.4 Natural Gas Combustion 1.4-1
1.5 Liquified Petroleum Gas Combustion 1.5-1
1.6 Wood Waste Combustion In Boilers 1.6-1
1.7 Lignite Combustion 1.7-1
1.8 Bagasse Combustion In Sugar Mills 1.8-1
1.9 Residential Fireplaces 1.9-1
1.10 Residential Wood Stoves 1.10-1
1.11 Waste Oil Combustion 1.11-1
2. SOLID WASTE DISPOSAL 2.0-1
2.1 Refuse Combustion 2.1-1
2.2 Automobile Body Incineration 2.2-1
2.3 Conical Burners 2.3-1
2.4 Open Burning 2.4-1
2.5 Sewage Sludge Incineration 2.5-1
3. STATIONARY INTERNAL COMBUSTION SOURCES 3.0-1
Glossary Of Terms Vol. II
Highway Vehicles Vol. II
Off Highway Mobile Sources Vol. II
3.1 Stationary Gas Turbines For Electric Utility
Power Plants 3.1-1
3.2 Heavy Duty Natural Gas Fired Pipeline
Compressor Engines 3.2-1
3.3 Gasoline And Diesel Industrial Engines 3.3-1
3.4 Stationary Large Bore And Dual Fuel Engines 3.4-1
4. EVAPORATION LOSS SOURCES 4.1-1
4.1 Dry Cleaning 4.1-1
4.2 Surface Coating 4.2-1
4.3 Storage Of Organic Liquids 4.3-1
4.4 Transportation And Marketing Of Petroleum Liquids 4.4-1
4.5 Cutback Asphalt, Emulsified Asphalt And Asphalt Cement .. 4.5-1
4.6 Solvent Degreasing 4.6-1
4.7 Waste Solvent Reclamation 4.7-1
4.8 Tank And Drum Cleaning 4.8-1
4.9 Graphic Arts 4.9-1
4.10 Commercial/Consumer Solvent Use 4.10-1
4.11 Textile Fabric Printing 4.11-1
4.12 Polyester Resin Plastics Product Fabrication 4.12-1
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Page
5. CHEMICAL PROCESS INDUSTRY 5.1-1
5.1 Adipic Acid 5.1-1
5.2 Synthetic Ammonia 5.2-1
5.3 Carbon Black 5.3-1
5.4 Charcoal 5.4-1
5.5 Chlor-Alkali 5.5-1
5.6 Explosives 5.6-1
5.7 Hydrochloric Acid 5.7-1
5.8 Hydrofluoric Acid 5.8-1
5.9 Nitric Acid 5.9-1
5.10 Paint And Varnish 5.10-1
5 .11 Phosphoric Acid 5 .11-1
5.12 Phthalic Anhydride 5 .12-1
5.13 Plastics 5.13-1
5.14 Printing Ink 5.14-1
5.15 Soap And Detergents 5.15-1
5.16 Sodium Carbonate 5.16-1
5.17 Sulfuric Acid 5.17-1
5.18 Sulfur Recovery 5.18-1
5.19 Synthetic Fibers 5.19-1
5.20 Synthetic Rubber 5.20-1
5.21 Terephthalic Acid 5.21-1
5 . 22 Lead Alkyl 5 . 22-1
5.23 Pharmaceuticals Production 5.23-1
5.24 Maleic Anhydride 5.24-1
6. FOOD AND AGRICULTURAL INDUSTRY 6.1-1
6.1 Alfalfa Dehydrating 6.1-1
6.2 Coffee Roasting 6.2-1
6.3 Cotton Ginning 6.3-1
6.4 Grain Elevators And Processing Plants 6.4-1
6.5 Fermentation 6.5-1
6.6 Fish Processing 6.6-1
6.7 Meat Smokehouses 6.7-1
6.8 Ammonium Nitrate Fertilizers 6.8-1
6.9 Orchard Heaters 6.9-1
6 .10 Phosphate Fertilizers 6 .10-1
6.11 Starch Manufacturing 6.11-1
6.12 Sugar Cane Processing 6.12-1
6.13 Bread Baking 6.13-1
6 .14 Urea 6 .14-1
6.15 Beef Cattle Feedlots 6.15-1
6.16 Defoliation And Harvesting Of Cotton 6.16-1
6.17 Harvesting Of Grain 6.17-1
6.18 Ammonium Sulfate 6.18-1
7. METALLURGICAL INDUSTRY 7.1-1
7.1 Primary Aluminum Production 7.1-1
7.2 Coke Production 7.2-1
7.3 Primary Copper Smelting 7.3-1
7.4 Ferroalloy Production 7.4-1
VI
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Page
7.5 Iron And Steel Production 7.5-1
7.6 Primary Lead Smelting 7.6-1
7.7 Zinc Smelting 7.7-1
7.8 Secondary Aluminum Operations 7.8-1
7.9 Secondary Copper Smelting And Alloying 7.9-1
7 .10 Gray Iron Foundries 7 .10-1
7.11 Secondary Lead Processing 7.11-1
7.12 Secondary Magnesium Smelting 7.12-1
7.13 Steel Foundries 7.13-1
7.14 Secondary Zinc Processing 7.14-1
7.15 Storage Battery Production 7.15-1
7.16 Lead Oxide And Pigment Production 7.16-1
7.17 Miscellaneous Lead Products 7.17-1
7.18 Leadbearing Ore Crushing And Grinding 7.18-1
8. MINERAL PRODUCTS INDUSTRY 8.1-1
8.1 Asphaltic Concrete Plants 8.1-1
8.2 Asphalt Roofing 8.2-1
8.3 Bricks And Related Clay Products 8.3-1
8.4 Calcium Carbide Manufacturing 8.4-1
8.5 Castable Refractories 8.5-1
8.6 Portland Cement Manufacturing 8.6-1
8.7 Ceramic Clay Manufacturing 8.7-1
8.8 Clay And Fly Ash Sintering 8.8-1
8.9 Coal Cleaning 8.9-1
8.10 Concrete Batching 8.10-1
8.11 Glass Fiber Manufacturing 8.11-1
8.12 Frit Manufacturing 8.12-1
8.13 Glass Manufacturing 8.13-1
8.14 Gypsum Manufacturing 8.14-1
8.15 Lime Manufacturing 8.15-1
8.16 Mineral Wool Manufacturing 8.16-1
8.17 Perlite Manufacturing 8.17-1
8.18 Phosphate Rock Processing 8.18-1
8.19 Construction Aggregate Processing 8.19-1
8.20 [Reserved] 8.20-1
8.21 Coal Conversion 8.21-1
8.22 Taconite Ore Processing 8.22-1
8.23 Metallic Minerals Processing 8.23-1
8.24 Western Surface Coal Mining 8.24-1
9. PETROLEUM INDUSTRY 9.1-1
9.1 Petroleum Refining 9.1-1
9.2 Natural Gas Processing 9.2-1
10. WOOD PRODUCTS INDUSTRY 10.1-1
10.1 Chemical Wood Pulping 10.1-1
10.2 Pulpboard 10.2-1
10.3 Plywood Veneer And Layout Operations 10.3-1
10.4 Woodworking Waste Collection Operations 10.4-1
VII
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Page
11. MISCELLANEOUS SOURCES 11.1-1
11.1 Wildfires And Prescribed Burning 11.1-1
11.2 Fugitive Dust Sources 11.2-1
• 11.3 Explosives Detonation 11.3-1
APPENDIX A Miscellaneous Data And Conversion Factors
APPENDIX B (Reserved For Future Use)
A-l
APPENDIX C.I Particle Size Distribution Data And Sized Emission
Factors For Selected Sources C.l-1
APPENDIX C.2 Generalized Particle Size Distributions C.2-1
APPENDIX C.3 Silt Analysis Procedures C.3-1
APPENDIX D Procedures For Sampling Surface/Bulk Dust Loading .... D-l
APPENDIX E Procedures For Laboratory Analysis Of Surface/Bulk
Dust Loading Samples E-l
viii
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KEY WORD INDEX
Acid
Adipic 5.1
Hydrochloric 5,7
Hydrofluoric 5.8
Phosphoric 5.11
Sulf uric 5.17
Terephthalic 5.21
Adipic Acid 5.1
Aggregate, Construction , 8 .19
Aggregate Storage Piles
Fugitive Dust Sources 11.2
Agricultural Tilling
Fugitive Dust Sources 11.2
Alfalfa Dehydrating 6.1
Alkali, Chlor- 5.5
Alloys
Ferroalloy Production 7.4
Secondary Copper Smelting And Alloying 7.9
Aluminum
Primary Aluminum Production 7.1
Secondary Aluminum Operations 7.8
Ammonia, Synthetic 5.2
Ammonium Nitrate Fertilizers 6.8
Anhydride, Phthalic 5.12
Anthracite Coal Combustion 1.2
Ash
Fly Ash Sintering 8.8
Asphalt
Cutback Asphalt, Emulsified Asphalt And Asphalt Cement 4.5
Roofing 8.2
Asphaltic Concrete Plants 8.1
Automobile Body Incineration 2.2
Bagasse Combustion In Sugar Mills 1.8
Baking, Bread 6.13
Bark
Wood Waste Combustion In Boilers 1.6
Batching, Concrete 8.10
Battery
Storage Battery Production 7.15
Beer Production
Fermentation 6.5
Bituminous Coal Combustion 1.1
Bread Baking 6.13
Bricks And Related Clay Products 8.3
Burners, Conical (Teepee) 2.3
Burning, Open 2.4
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Calcium Carbide Manufacturing 8.4
Cane
Sugar CAne Processing 6.12
Carbon Black 5.3
Carbonate
Sodium Carbonate Manufacturing 5.16
Castable Refractories 8.5
Cattle
Beef Cattle Feedlots 6 .15
Cement
Asphalt 4.5
Portland Cement Manufacturing 8.6
Ceramic Clay Manufacturing 8.7
Charcoal 5.4
Chemical Wood Pulping 10.1
Chlor-Alkali 5.5
Clay
Bricks And Related Clay Products 8.3
Ceramic Clay Manufacturing 8.7
Clay And Fly Ash Sintering 8.8
Cleaning
Coal 8.9
Dry 4.1
Tank And Drum 4.8
Coal
Anthracite Coal Combustion 1.2
Bituminous Coal Combustion 1.1
Cleaning 8.9
Conversion 8.21
Coating, Surface 4.2
Coffee Roasting 6.2
Coke Manufacturing 7.2
Combustion
Anthracite Coal 1.2
Bagasse, In Sugar Mills 1.8
Bituminous Coal 1.1
Fuel Oil 1.3
Internal Vol. 11
Lignite 1.7
Liquified Petroleum Gas 1.5
Natural Gas 1.4
Orchard Heaters 6.9
Residential Fireplaces 1.9
Waste Oil 1.11
Wood Stoves 1.10
Concrete
Asphaltic Concrete Plants 8.1
Concrete Batching 8 .10
Conical (Teepee) Burners 2.3
Construction Aggregate 8.19
Construction Operations
Fugitive Dust Sources * 11.2
Conversion, Coal 8. 21
Wood Waste In Boilers 1.6
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Copper
Primary Copper Smelting 7.3
Secondary copper Smelting And Alloying 7.9
Cotton
Defoliation And Harvesting 6.16
Ginning 6.3
Dacron
Synthetic Fibers 5.19
Defoliation, Cotton 6 .16
Degreasing, Solvent 4.6
Dehydrating, Alfalfa 6.1
Detergents
Soap And Detergents 5.15
Detonation, Explosives 11.3
Drum
Tank And Drum Cleaning 4.8
Dry Cleaning 4.1
Dual Fuel Engines, Stationary 3.4
Dust
Fugitive Dust Sources ; 11.2
Dust Loading Sampling Procedures App. D
Dust Loading Analysis App. E
Electric Utility Power Plants, Gas 3.1
Elevators , Feed And Grain Mills 6.4
Explosives 5.6
Explosives Detonation 11.3
Feed
Beef Cattle Feedlots 6.15
Feed And Grain Mills And Elevators " 6.4
Fermentation 6.5
Fertilizers
Ammonium Nitrate 6.8
Phosphate 6 .10
Ferroalloy Production 7.4
Fiber
Glass Fiber Manufacturing 8.11
Fiber, Synthetic 5 .19
Fires
Forest Wildfires And Prescribed Burning 11.1
Fireplaces , Residential 1.9
Fish Processing 6.6
Fly Ash
Clay And Fly Ash Sintering 8.8
Foundries
Gray Iron Foundries 7 .10
Steel Foundries 7 .13
Frit Manufacturing 8.12
Fuel Oil Combustion 1.3
Fugitive Dust Sources 11.2
XI
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Gas Combustion, Liquified Petroleum 1.5
Gas, Natural
Natural Gas Combustion 1.4
Natural Gas Processing 9.2
Gasoline/Diesel Engines 3.3
Ginning, Cotton • 6.3
Glass Manufacturing 8.13
Glass Fiber Manufacturing 8.11
Grain
Feed And Grain Mills And Elevators 6.4
Harvesting Of Grain 6 .17
Gravel
Sand And Gravel Processing 8 .19
Gray Iron Foundries 7 .10
Gypsum Manufacturing .• 8 .14
Harvesting
Cotton 6.16
Grain 6 .17
Heaters , Orchard 6.9
Hydrochloric Acid 5.7
Hydrofluoric Acid 5.8
Incineration
Automobile Body 2.2
Conical (Teepee) 2.3
Refuse 2.1
Sewage Sludge 2.5
Industrial Engines, Gasoline And Diesel 3.3
Ink, Printing 5.14
Internal Combustion Engines
Highway Vehicles Vol. II
Off Highway Mobile Sources Vol. II
Off Highway Stationary Sources 3.0
Iron
Ferroalloy Production 7.4
Gray Iron Foundries 7 .10
Iron And Steel Mills 7.5
Taconite Ore Processing 8.22
Large Bore Engines 3.4
Lead
Leadbearing Ore Crushing And Grinding 7 .18
Miscellaneous Lead Products 7.17
Primary Lead Smelting 7.6
Secondary Lead Smelting 7.11
Lead Alkyl 5.22
Lead Oxide And Pigment Production 7 .16
Leadbearing Ore Crushing And Grinding 7 .18
Lignite Combustion 1.7
Lime Manufacturing 8.15
Liquified Petroleum Gas Combustion 1.5
xii
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Magnesium
Secondary Magnesium Smelting 7.12
Magnetic Tape Manufacturing 4.2
Maleic Anhydride 5.24
Marketing
Transportation And Marketing Of Petroleum Liquids 4.4
Meat Smokehouses 6.7
Mineral Wool Manufacturing 8.16
Mobile Sources
Highway Vol. II
Off Highway Vol. II
Natural Gas Combustion 1.4
Natural Gas Fired Pipeline Compressors 3.2
Natural Gas Processing 9.2
Nitric Acid Manufacturing 5.9
Off Highway Mobile Sources Vol. II
Off Highway Stationary Sources 3.0
Oil
Fuel Oil Combustion 1.3
Waste Oil Combustion 1.11
Open Burning 2.4
Orchard Heaters 6.9
Ore Processing
Leadbearing Ore Crushing And Grinding 7.18
Taconite 8.22
Organic Liquids, Storage 4.3
Paint And Varnish Manufacturing 5.10
Paved Roads
Fugitive Dust Sources 11.2
Perlite Manufacturing 8 .17
Petroleum
Liquified Petroleum Gas Combustion 1.5
Refining 9.1
Storage Of Organic Liquids 4.3
Transportation And Marketing Of Petroleum Liquids 4.4
Pharmaceuticals Production 5 . 23
Phosphate Fertilizers 6 .10
Phosphate Rock Processing 8.18
Phosphoric Acid 5.11
Phthalic Anhydride 5.12
Pigment
Lead Oxide And Pigment Production 7 .16
Pipeline Compressors 3.2
Plastics 5.13
Plywood Veneer And Layout Operations 10. 3
Polyester Resin Plastics Product Fabrication 4.12
Portland Cement Manufacturing 8.6
Prescribed Burning 11.1
Printing Ink 5 .14
Pulpboard 10.2
Pulping, Chemical Wood 10.1
xiii
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Reclamation, Waste Solvent 4.7
Recovery, Sulfur 5.18
Refractories , Castable 8.5
Residential Fireplaces 1.9
Roads, Paved
Fugitive Dust Sources 11.2
Roads, Unpaved
Fugitive Dust Sources 11.2
Roasting Coffee 6.2
Rock
Phosphate 'Rock Processing 8.18
Roofing, Asphalt 8.2
Rubber, Synthetic 5.20
Sand And Gravel Processing 8.19
Sewage Sludge Incineration 2.5
Sintering, Clay And Fly Ash 8.8
Smelting
Primary Copper Smelting 7.3
Primary Lead Smelting 7.6
Secondary Copper Smelting And Alloying 7.9
Secondary Lead Smelting 7 .11
Secondary Magnesium Smelting 7.12
Zinc Smelting 7.7
Smokehouses , Meat 6.7
Soap And Detergent Manufacturing 5 .15
Sodium Carbonate Manufacturing 5 .16
Solvent
Commercial/Consumer Use 4.10
Solvent Degreasing 4.6
Waste Solvent Reclamation 4.7
Starch Manufacturing 6.11
Stationary Gas Turbines 3.1
Stationary Sources, Off Highway 3.0
Steel
Iron And Steel Mills 7.5
Steel Foundries 7 .13
Storage Battery Production 7.15
Storage Of Organic Liquids 4.3
Sugar Cane Processing 6.12
Sugar Mills, Bagasse Combustion In 1.8
Sulfur Recovery 5.18
Sulfuric Acid 5.17
Surface Coating 4.2
Synthetic Ammonia 5.2
Synthetic Fiber 5.19
Synthetic Rubber 5 . 20
Taconite Ore Processing 8.22
Tank And Drum Cleaning t 4.8
Tape , Magnetic 4.2
Terephthalic Acid 5.21
xiv
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Tilling, Agricultural
Fugitive Dust Sources 11.2
Transportation And Marketing Of Petroleum Liquids 4.4
Turbine Engines, Natural Gas 3.1
Unpaved Roads
Fugitive Dust Sources 11.2
Urea 6.14
Varnish
Paint And Varnish Manufacturing 5 .10
Vehicles, Highway And Off Highway Vol. II
Waste Solvent Reclamation 4.7
Waste Oil Combustion 1.11
Whiskey Production
Fermentation 6.5
Wildfires, Forest 11.1
Wine Making
Fermentation 6.5
Wood Pulping, Chemical 10.1
Wood Stoves 1.10
Wood Waste Combustion In Boilers 1.6
Woodworking Waste Collection Operations 10.4
Zinc
Secondary Zinc Processing 7 .14
Smelting 7.7
xv
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1.10 RESIDENTIAL WOOD STOVES
1.10.1 General1"3
Wood stoves are commonly used as space heaters in residences to
supplement conventional heating systems. They are increasingly found as the
primary source of residential heat.
Because of differences in both the magnitude and the composition of
emissions from wood stoves, four different categories of stoves should be
considered when estimating emissions:
the conventional noncatalytic wood stove,
the noncatalytic low emitting wood stove,
the pellet fired noncatalytic wood stove, and
the catalytic wood stove.
Among these categories, there are many variations in wood stove design
and operation characteristics.
The conventional stove category comprises all stoves without catalytic
combustors not included in the other noncatalytic categories. Stoves of many
different airflow designs, such as updraft, downdraft, crossdraft, and S-flow,
may be in this category.
"Noncatalytic low emitting" wood stoves are those units properly
installed, haying no catalyst and meeting EPA certification standards as of
July 1, 1990.l
Pellet fired stoves are those fueled with pellets of sawdust, wood
products, and other biomass materials pressed into manageable shape and size.
These stoves have a specially designed or modified grate to accommodate this
type of fuel.
Catalytic stoves are equipped with a ceramic or metal honeycomb device,
called a combustor or converter, that is coated with a noble metal such as
platinum or palladium. The catalyst material reduces the ignition temperature
of the unburned hydrocarbons and carbon monoxide in the exhaust gases, thus
augmenting their ignition and combustion at normal stove operating
temperatures. As these components of the gases burn, the temperature inside
the catalyst increases to a point where the ignition of the gases is
essentially selfsustaining. The particulate emissions data in Table 1.10
represent the field operation emissions expected from properly installed
catalytic wood heaters meeting the EPA July 1, 1990 certification standards.
9/90 External Combustion Sources 1.10-1
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1.10.2 Emissions4"15
The combustion and pyrolysis of wood in wood stoves produce atmospheric
emissions of particulate, carbon monoxide, nitrogen oxides, organic compounds,
mineral residues, and to a lesser extent, sulfur oxides. The quantities and
types of emissions are highly variable and depend on a number of factors,
including the stages of the combustion cycle. During initial stages of
burning, after a new wood charge is introduced, emissions increase
dramatically and are primarily volatile organic compounds (VOC). After the
initial period of high burn rate, there is a charcoal stage of the burn cycle,
characterized by a slower burn rate and decreased emission rates. Emission
rates during this stage are cyclical, characterized by relatively long periods
of low emissions with shorter episodes of emission spikes.
Particulate emissions are defined in this document as the total catch
measured by the EPA Method 5H (Oregon Method 7) sampling train. A small
portion of wood stove particulate emissions includes "solid" particles of
elemental carbon and wood. The vast majority of particulate emissions is
condensed organic products of incomplete combustion equal to or less than 10
micrometers in aerodynamic diameter (PM-,Q). The particulate emission values
shown in Table 1.10-1 represent estimates of emissions produced by wood
heaters expected to be available over the next few years as cleaner, more
reliable wood stoves are manufactured to meet the New Source Performance
Standards. These emission values are derived from limited field test data
from studies of the best available wood stove control technology. Still,
there is a potential for higher emissions from some wood stove models.
In addition, the values for particulate and carbon monoxide emissions on
the table reflect tests of new units. Control devices on wood stoves may
exhibit reduced control efficiency over a period of operation, resulting in
increased emissions 3 to 5 years after installation. For catalyst equipped
wood heaters, the potential for control degradation is probably on the order
of 10 to 30 percent after 3 years of operation. Control degradation for any
stoves, including low emitting noncatalyst wood stoves may also occur, as a
result of deteriorated seals and gaskets, misaligned baffles and bypass
mechanisms, broken refractory , or other damaged functional components. The
increase in emissions resulting from such control degradation has not been
quantified, but can be significant.
Although reported particle size data are scarce, one reference states
that 95 percent of the particles in the emissions from a wood stove were less
than 0.4 micrometers in size.
Sulfur oxides are formed by oxidation of sulfur in the wood. Nitrogen
oxides are formed by oxidation of fuel and atmospheric nitrogen. Mineral
constituents, such as potassium and sodium compounds, are also released from
the wood matrix during combustion. The high levels of organic compound and
carbon monoxide emissions result from incomplete combustion of the wood.
1.10-2 EMISSION FACTORS 9/90
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VO
O
TABLE 1.10-1. EMISSION FACTORS FOR COMBUSTION IN RESIDENTIAL WOOD STOVES
m
X
rt
(D
H*
O
O
a
r
CO
ft.
rr
H-
O
3
w
O
1-4
r»
O
n>
w
Stove
type
Conventional
units
" Phased
urits9
Catalytic
Noncatalytic
Pellet fired
aPhase II units
Particulatea'b-c Carbon Nitrogen Sulfur Volatile organicsd
<10um monoxideb oxides6 oxides6 ....
- ^ Methane Nonmethane
15 (30) 140 (270) 1.4 (2.8)f 0.2 (0.4) 32 (64) 14 (28)
*'
6.6 (13) 39 (78) 1.0 (2.0) 0.2 (0.4) 13 (26) 8.6 (17)
9.6 (19) 130 (260) - 0.2 (0.4)
1.6 (3.2) 18 (36) 6.9h (14) 0.2 (0.4)
are subject to 10 to 30% degradation within the first 3 years of use. Units are
Efficiency6
(%)
52
72
63
78
g/kg (Ib/ton) of dry wood burned. Dash = no data.
References 2-8. Emission Factor Rating for paniculate, CO and SOX: C; for NOX: E. Based on field tests described
in Reference 8.
cReference 1. Defined as equivalent to total catch by EPA Method 5H (Oregon Method 7) train.
References 6,9. Emission Factor Rating: E. Calculated by adding the estimated mass of simple hydrocarbon
material C1 - C7 data to total chromatographable organics.
8Reference 1. Overall efficiency represents sum of combustion and transfer efficiencies, and values represent
averages of laboratory test results.
'References 12,15. Emission Factor Rating: C.
SReference 1. Expected from wood heaters meeting NSPS after July 1,1990.
Reference 6. Based on a single data point.
-------
Organic constituents of wood smoke vary considerably in both type and
volatility. These constituents include simple hydrocarbons of carbon number 1
through 7 (Cl - C7), which exist as gases or which volatilize at ambient
conditions, and complex low volatility substances that condense at ambient
conditions. These low volatility condensible materials generally are
considered to have boiling points below 300°C (572°F).
Polycyclic organic matter (POM) is an important component of the
condensible fraction of wood smoke. POM contains a wide range of compounds,
including organic compounds formed by the combination of free radical species
in the flame zone through incomplete combustion. This group contains some
potentially carcinogenic compounds, such as benzo(a)pyrene.
Emission factors and their ratings for wood combustion in residential
wood stoves are presented in Table 1.10-1.
As mentioned, particulate emissions are defined as the total emissions
equivalent to that collected by EPA Method 5H (Oregon Method 7). This method
employs a heated filter followed by three impingers, an unheated filter, and a
final impinger. Particulate emissions data used to develop the factors in
Table 1.10-1 are primarily from data collected during field testing programs,
and they are presented as values equivalent to that collected with Method 5H.
Conversions are employed, as appropriate, for data collected with other
methods. See Reference 2 for detailed discussions of EPA Methods 5H and 28.
Other emission factors shown in Table 1.10-1 have been developed from data
collected during laboratory testing programs.
References for Section 1.10
1. Standards Of Performance For New Stationary Sources: New Residential
Wood Heaters. 53 FR 5860, February 26, 1988.
2 . G. E. Weant, Emission Factor Documentation For AP-42 Section 1.10.
Residential Wood Stoves. EPA-450/4-89-007, U. S. Environmental
Protection Agency, Research Triangle Park, NC, May 1989.
3. R. Gay and J. Shah, Technical Support Document For Residential Wood
Combustion. EPA-450/4-85-012, U. S. Environmental Protection Agency,
Research Triangle Park, NC, February 1986.
4. Residential Wood Heater Test Report. Phase 1. Tennessee Valley
Authority, Chattanooga, TN, November 1982.
5. J. A. Rau and J. J. Huntzicker, "Composition And Size Distribution Of
Residential Wood Smoke Aerosols". Presented at the 21st Annual Meeting
of the Air And Waste Management Association, Pacific Northwest
International Section, Portland, OR, November 1984.
1.10-4 EMISSION FACTORS 9/90
-------
6. R. C. McCrillis and R. G. Merrill, "Emission Control Effectiveness Of A
Woodstove Catalyst And Emission Measurement Methods Comparison".
Presented at the 78th Annual Meeting of the Air And Waste Management
Association, Detroit, MI, 1985.
7. L. E. Cottone and E. Me'sser, Test Method Evaluations And Emissions
Testing For Rating Wood Stoves. EPA-600/2-86-100, U. S. Environmental
Protection Agency, Cincinnati, OH, October 1986.
8. In-situ Emission Factors For Residential Wood Combustion Units.
EPA-450/3-88-013, U. S. Environmental Protection Agency, Research
Triangle Park, NC, December 1988.
9. K. E. Leese and S. M. Harkins, Effects Of Burn Rate. Wood Species.
Moisture Content. And Weight' Of Wood Loaded On Woodstove Emissions. EPA-
600/2-89-025, U. S. Environmental Protection Agency, Cincinnati, OH, May
1989.
10. Residential Wood -Heater Test Report. Phase II. Vol. 1. Tennessee Valley
Authority, Chattanooga, TN, August 1983.
11. J. M. Allen, et al.. Study Of The Effectiveness Of A Catalytic
Combustion Device On A Wood Burning Appliance. EPA-600/7-84-04, U. S.
Environmental Protection Agency, Cincinnati, OH, March 1984.
12. J. M. Allen and W. M. Cooke, Control Of Emissions From Residential Wood
Burning By Combustion Modification. EPA-600/7-81-091, U. S.
Environmental Protection Agency, Cincinnati, OH, May 1981.
13. R. S. Truesdale and J. G. Cleland, "Residential Stove Emissions From
Coal And Other Fuels Combustion". Presented at the Specialty
Conference on Residential Wood and Coal Combustion, Louisville, KY,
March 1982.
14. R. E. Imhoff, et al.. "Final Report On A Study Of The Ambient Impact Of
Residential Wood Combustion in Petersville, Alabama". Presented at the
Specialty Conference on Residential Wood and Coal Combustion,
Louisville, KY, March 1982.
15. D. G. Deangelis, et al.. Preliminary Characterization Of Emissions From
Wood-fired Residential Combustion Equipment. EPA-600/7-80-040, U. S.
Environmental Protection Agency, Cincinnati, OH, March 1980.
External Combustion Sources 1.10-5
-------
2.1 REFUSE COMBUSTION
Refuse combustion is generally the burning of predominantly nonhazardous
garbage or other solid wastes. Types of combustion devices used to burn
refuse include single chamber units, multiple chamber units, trench
incinerators, controlled air incinerators, and pathological incinerators.
These devices are used to burn municipal, commercial, industrial,
pathological, and domestic refuse.
2.1.1 Municipal Waste Combustion
There are currently over 150 municipal waste combustion (MWC) plants in
operation in the United States. Three main types of combustors are used:
mass burn, modular, and refuse derived fuel (RDF) fired. In mass burn units,
the municipal solid waste (MSW) is combusted without any preprocessing other
than removal of items too large to go through the feed system. In a typical
mass burn combustor, refuse is placed on a grate that moves through the
combustor. Combustion air in excess of stoichiometric amounts is supplied
both below (underfire air) and above (overfire air) the grate. Mass burn
combustors are usually erected at the site (as opposed to being prefabricated
at another location) and range in size from 46 to 900 megagrams (50 to 1000
tons) per day of refuse throughput per unit. Many mass burn facilities have
two or more combustors and have combined site capacities of greater than 900
megagrams (1000 tons) per day. The mass burn category can be further divided
into waterwall and refractory wall designs. Most refractory wall combustors
were built prior to the early 1970s. Newer units are mainly waterwall
designs, which have water-filled tubes in the walls of the combustor used to
recover heat for production of steam and/or electricity. Process diagrams for
one type of refractory wall combustor and a typical waterwall combustor are
presented in Figures 2.1.1-1 and 2.1.1-2, respectively.
Modular combustors also burn waste without preprocessing, but they are
typically shop fabricated and generally range in size from 5 to 110 megagrams
(5 to 120 tons) per day of refuse throughput. One of the most common types of
modular combustors is the starved air or controlled air type, incorporating
two combustion chambers. A process diagram of a typical modular starved-air
combustor is presented in Figure 2.1.1-3. Air is supplied to the primary
chamber at substoichio-metric levels. The incomplete combustion products
(carbon monoxide and organic compounds) pass into the secondary combustion
chamber where excess air is added and combustion is completed. Another type
of modular combustor, functionally similar to mass burn units, uses excess air
in the primary chamber.
Refuse derived fuel fired combustors burn processed waste which may vary
from shredded waste to finely divided fuel suitable for co-firing with
pulverized coal. A process diagram for a typical RDF combustor is shown in
Figure 2.1.1-4. Preprocessing usually consists of removing noncombustibles
and shredding the waste, which raises the heating value and provides a more
9/90 Solid Waste Disposal 2.1-1
-------
Stack
inr
L-«JI Ii
Waste Tipping ROOT
I ^
1 Bottom
Q"?Jch Conveyor
Pit
Ash
Conveyors
Figure 2.1-1. Mass burn refractory wall combustor with grate/rotary kiln.
vvv
S' . 2
<_jl[ •*•-"
2.1-2
Figure 2.1-2. Mass burn waterwall combustor.
EMISSION FACTORS
9/90
-------
To Dump Stack or
Waste Heat Boiler
Secondary
Chamber
'Gas Burner
Primary Air
Quench
Figure 2.1-3. Modular starved-air combustor with transfer rams.
9/90
Figure 2.1-4. RDF fired spreader stoker boiler.
Solid Waste Disposal
2.1-3
-------
uniform fuel. Combustor sizes range from 290 to 1,300 megagrams (320 to 1400
tons) per day. Most RDF facilities have two or more combustors, and site
capacities range up to 2700 megagrams (3000 tons) per day. RDF facilities
typically recover heat for production of steam and/or electricity.
There are also small, numbers of other types of MWCs. One type used less
extensively is the rotary waterwall combustor. As with mass burn units,
rotary waterwall combustors burn waste without preprocessing but differ in
design from most mass burn units in the use of a rotary combustion chamber
equipped with water-filled tubes for heat recovery. Other types of MWCs
include batch incinerators and fluidized bed combustors.
Over 30 percent of the units currently operating are mass burn units
(including refractory and waterwall) and another 40 to 50 percent are modular
units. Over 10 percent of the. units are RDF units and the remainder of the
units are of other designs. In terms of waste combusted, mass burn units
account for about 60 percent of the MSW combusted, modular units account for 8
percent, and RDF units for 30 percent.
2.1.1.1 Process Description
Types of combustors described in this section include:
- Mass burn refractory wall
- Mass burn waterwall
- Refuse derived fuel fired
- Modular starved air
- Modular excess air
- Rotary waterwall
- Fluidized bed
Mass Burn Refractory Wall - At least three distinct combustor designs
make up the existing population of refractory wall combustors. The first
design is a batch fed upright combustor, where the combustor may be
cylindrical or rectangular in shape. This type of combustor was prevalent in
the 1950s, but no additional units of this design are expected to be built.
A more common design consists of rectangular combustion chambers with
traveling, rocking, or reciprocating grates. This type of combustor is
continuously fed and operates in an excess air mode with both underfire and
overfire air provided. The primary distinction between plants with this
design is the manner in which the waste is moved through the combustor. The
traveling grate moves on a set of sprockets and does not agitate the waste bed
as it advances through the combustor. Rocking and reciprocating grate systems
agitate and aerate the waste bed as it advances through the combustion
chamber. The system generally discharges the ash at the end of the grates to
a water quench pit for collection and disposal in a landfill.
A third major design type in the mass burn refractory wall population is
a system which combines grate burning technology with a rotary kiln. Two
grate sections (drying and ignition) precede a refractory lined rotary kiln.
Combustion is completed in the kiln, and ash leaving the kiln falls into a
water quench. This system is depicted in Figure 2.1.1-1.
2.1-4 EMISSION FACTORS 9/90
-------
Most mass burn refractory wall combustors have electrostatic
precipitators (ESPs) for particulate control. Others have a wet particulate
control device, such as a wet scrubber.
Mass Burn Waterwall - With this type of system, unprocessed waste with
large, bulky, noncombustibles removed is delivered by an overhead crane to a
feed hopper from which it is fed into the combustion chamber. Earlier mass
burn designs utilized gravity feeders, but it is more typical today to feed by
means of single or dual hydraulic rams that operate on a set frequency.
Nearly all modern conventional mass burn facilities utilize
reciprocating grates to move the waste through the combustion chamber. The
grates typically include two or three separate sections where designated
stages in the combustion process occur. The initial grate section is referred
to as the drying grate, where heat reduces the moisture content of the waste
prior to ignition. The second grate section is the burning grate, where the
majority of active burning takes place. The third grate section is referred
to as the burnout or finishing grate, where remaining combustibles are burned.
Smaller units may have two rather than three individual grate sections.
Bottom ash is discharged from the finishing grate into a water filled ash
quench pit. Dry ash systems have been used in some designs, but are not
widespread.
Combustion air is added to the waste from beneath the grate by way of
underfire air plenums. The majority of mass burn waterwall systems supply
underfire air to the individual grate sections through multiple plenums. As
the waste bed burns, additional air is required to oxidize fuel rich gases and
complete the combustion process. Overfire air is injected through rows of
high pressure nozzles (usually two to three inches in diameter). Typically,
mass burn waterwall MWCs are operated with 80 to 100 percent excess air.
The majority of mass burn waterwall combustors have ESPs for particulate
control. Several plants have acid gas controls in combination with a fabric
filter or ESP.
Refuse Derived Fuel - As a means of raising the heating value, raw MSW
can be processed to refuse derived fuel (RDF) before combustion. A set of
standards for classifying RDF types has been established by the American
Society For Testing And Materials. The type of RDF used is dependent on the
boiler design. Boilers.that are designed to burn RDF as a primary fuel
usually utilize spreader stokers and fire RDF-3 (fluff, or f-RDF) in a semi-
suspension mode. This mode of feeding is accomplished by using an air swept
distributor, which allows a portion of the feed to burn in suspension and the
remainder to be burned out after falling on a horizontal traveling grate.
Suspension fired RDF boilers, such as pulverized coal (PC) fired boilers,
can co-fire RDF-3 or RDF-4 (powdered or p-RDF). If RDF-3 is used, the fuel
processing must be more extensive so that a very fine fluff results.
Currently, PC boilers co-fire fluff with pulverized coal. Suspension firing
is usually associated with larger boilers due to the increased boiler height
and retention time required for combustion to be completed in total
suspension. Smaller systems firing RDF in suspension require moving or dump
grates in the lower furnace to handle the falling material that is not
completely combusted in suspension. Boilers co-firing RDF in suspension are
generally limited to 50 percent RDF, based on heating value.
9/90 Solid Waste Disposal 2.1-5
-------
l-i
O
4J
O
a)
09
cu
»H
iH
O
O
a
12
10
8
6
4
2
ControlIt4
Uncontrolled
i iii
i ii iii
0.12
0.10
0.08
0.06
0.04
0.02
o
u
O
c
o
•H x~ »
U3 00
u as
•H ""^
a oo
•o
at
•u
•C
O
0.1
1.0 10
Ptrtlclt dUMttr
100
Figure 2.1-5. Cumulative particle size distribution and size
specific emission factors for mass burn combustors.
Vi
o
4J
o
(0
c
o
•H
CO x~^
.CO 00
oo
•O
0)
§
U
1.20
1.00
0.80
0.60
0.40
0.20
0
Control!
Uncontrolled
I I I I I I i I IIIMi
0.0150
0.0125
0.0100
0.0075
0.0050
0.0025
0
o
(0
c
o
•H /—.
0) 60
ca S
S "M
0) ^
0)
rH
•H
O
C
o
0.1
i.o
10
P«rticU
100
Figure 2.1-6.
Cumulative particle size distribution and size
specific emission factors for starved air combustors,
2.1-6
EMISSION FACTORS
9/90
-------
TABLE 2.1-1. EMISSION FACTORS FOR MUNICIPAL WASTE COMBUSTION3
VO
O
O
H-
P.
CU
in
rt
(D
O
CO
T)
O
Cfl
I-1
Particle Uncontrolled
diameter kg/Mg
Pollutant (ug) (Ib/ton)
PM10 0.625 2.7 (5.4)
1.0 3.5 (7.0)
2.5 4.6 (9.2)
5.0 6.0 (12)
10.0 7.0 (14)
15.0 9.0 (18)
Total particulate 19 (38)
Lead 0.09 (0.18)
Sulfur dioxided 0.85 (1.7)
Nitrogen oxides 1.8 (3.6)
Carbon monoxide 1.1 (2.2)
Volatile organic
compounds
Methane 0.0032 (0.0064)
Nonmethane 0.05 (0.10)
Mass Burn
Controlled Emission
kg/Mg Factor
(Ib/ton) Rating
0.055 (0.11)b C
0.065 (0.13)
0.075 (0.15)
0.080 (0.16)
0.090 (0.18)
0.10 (0.20)
0.19 (0.38)b C
0.011 (0.022)b C
0.55 (l.l)e D
1.8 (3.6) c D
1.1 (2.2)e D
0.0032 (0.0064)b D
0.05 (0.10)b D
Uncontrolled
kg/Mg
(Ib/ton)
0.40 (0.80)
0.50 (1.0)
0.60 (1.2)
0.65 (1.3)
0.70 (1.4)
0.75 (1.5)
0.95 (1.9)
0.06 (0.12)
0.85 (1.7)
2.2 (4.4)
0.17 (3.4)
NA
NA
Starved Air
Controlled Emission
kg/Mg Factor
(Ib/ton) Rating
0.0080 (0.016)b D
0.0095 (0.019)
0.010 (0.020)
0.011 (0.022)
0.012 (0.024)
0.013 (0.026)
0.015 (0.030)b D
0.001 (0.002)b D
0.55 (l.l)e D
2.2 (4.4)c D
0.17 (3.4)c D
NA
NA
Refuse-Derived Fuel
Uncontrolled
kg/Mg
(Ib/ton)
4.4 (8.8)
10 (20)
16 (32)
21 (42)
22 (44)
24 (48)
40 (80)
0.065 (0.13)
0.85 (1.7)
2.5 (5.0)
1.8 (3.6)
NA
NA
Controlled
kg/Mg
(Ib/ton)
0.090 (0.18)c
0.19 (0.38)
0.29 (0.58)
0.36 (0.72)
0.37 (0.74)
0.39 (0.78)
0.04 (0.08)c
Emission
Factor
Rating
E
D
0.014 (0.028)c D
0.55 (l.l)e
2.5 (5.0)°
1.8 (3.6)b
NA
NA
0
D
D
^Reference 7.
"Control devices include ESP and FF.
^Control device is an ESP.
Average for all three combustor types.
eControl devices include ESP, FF, dry scrubbers, and wet scrubbers.
-------
The emission controls for RDF systems are typically ESPs alone, although
acid gas controls are used with particulate control devices in some systems.
Modular Starved Air - The basic design of a modular starved air combustor
consists of two separate combustion chambers, "primary" and "secondary".
Waste is batch fed to the primary chamber by a hydraulically activated ram.
The charging bin is filled by a front end loader. Waste is fed automatically
on a set frequency, generally 6 to 10 minutes between charges.
Waste is moved through the primary combustion chamber by either hydraulic
transfer rams or reciprocating grates. Combustors using transfer rams have
individual hearths upon which combustion takes place. Grate systems generally
include two separate grate sections. In either case, waste retention times in
the primary chamber are long, up to 12 hours. Bottom ash is usually
discharged to a wet quench pit.
The quantity of air introduced in the primary chamber defines the rate at
which waste burns. The primary chamber essentially functions as a gasifier,
producing a hot fuel gas which is burned out in the secondary chamber. The
combustion air flow rate to the primary chamber is controlled to maintain an
exhaust gas temperature set point (generally 650 to 760°C [1200 to 1400°F]),
which normally corresponds to about 40 percent theoretical air. Other system
designs operate with-a primary chamber temperature between 870 to 980°C (1600
and 1800°F), which requires 50 to 60 percent theoretical air.
As the hot, fuel rich flue gases flow to the secondary chamber, they are
mixed with excess air to complete the burning process. The temperature of the
exhaust gases from the primary chamber is above the autoignition point. Thus,
completing combustion is simply a matter of introducing air to the fuel rich
gases. The amount of air added to the secondary chamber is controlled to
maintain a desired flue gas exit temperature, typically 980 to 1200°C (1800 to
2200°F). Approximately 80 percent of the total combustion air is introduced
as secondary air, so that excess air levels for the system are about 100
percent. Typical operating ranges vary from 80 to 150 percent excess air.
The walls of both combustion chambers are refractory lined. Early
starved air modular combustors did not include heat recovery, but a waste heat
boiler is common in newer installations, with two or more combustion modules
manifolded to a boiler. Combustors with heat recovery capabilities also have
dump stacks. A dump stack is an alternate emission point, located upstream of
the boiler and/or air pollution control equipment. It is for use in an
emergency, or when the boiler and/or air pollution control equipment are not
in operation.
Because emissions are relatively low, many modular starved air MWCs do
not have emissions control. Those that do usually have ESPs for particulate
control, although fabric filters have been used. A few newer starved air MWCs
have acid gas controls.
Modular Excess Air - This design is similar to that of modular starved
air units. The basic design includes two separate combustion chambers
(referred to as the "primary" and "secondary" chambers). Waste is batch fed
to the primary chamber, which is refractory lined. The waste is moved through
2.1-8 EMISSION FACTORS. 9/90
-------
VO
O
TABLE 2.1-2. CUMULATIVE PARTICLE SIZE DISTRIBUTION AND SIZE SPECIFIC EMISSION
FACTORS FOR MUNICIPAL WASTE COMBUSTORS3
Cumulative mass X <
Particle
Size
(ug)
15.0
10.0
5.0
2.5
1.0
0.625
Total
Uncontrolled
MB
47
37
32
24
18
14
100
SA
79
74
68
63
53
42
100
RDF
60
55
53
40
25
11
100
stated size
Controlled
MB
53
47
42
39
34
29
100
SA
87
80
73
67
63
53
100
RDF
71
67
65
53
35
16
100
Cumulative emission factor, kg/Mg (Ib/ton)
Uncontrolled
MB
9.0 (18)
7.0 (14)
6.0 (12)
4.6 (9.2)
3.5 (7.0)
2.7 (5.4)
19 (38)
SA
0.75 (1.5)
0.70 (1.4)
0.65 (1.3)
0.60 (1.2)
0.50 (1.0)
0.40 (0.80)
0.95 (1.9)
RDF
24 (48)
22 (44)
21 (42)
16 (32)
10 (20)
4.4 (8.8)
40 (80)
MB
0.10 (0.20)
0.090 (0.18)
0.080 (0.16)
0.075 (0.15)
0.065 (0.13)
0.055 (0.11)
0.19 (0.38)
Controlled
SA
0.013 (0.026)
0.012 (0.024)
0.011 (0.022)
0.010 (0.020)
0.0095 (0.019)
0.0080 (0.016)
0.015 (0.030)
RDF
0.39 (0.7)
0.37 (0.7)
0.36 (0.7)
0.29 (0.5)
0.19 (0.3)
0.09 (0.1)
0.55 (1.1)
00
O
W
ft
(D
O
I-"-
W
T3
O
to
fto
aReference 3. MB - mass burn. SA - starved air. DF - refuse-derived fuel.
-------
TABLE 2.1-3. UNCONTROLLED EMISSION FACTORS FOR INDUSTRIAL/COMMERCIAL REFUSE COMBUSTORSa
EMISSION FACTOR RATING: A
Incinerator type
Multiple chambers6
Single chambers
Trenchn
Wood
Rubber tires
Municipal refuse
Flue fed
Single chamber^
Modified0
Domestic single chamber
Without primary burner11
With primary burnerP
Pathological*!
Particulate
kg/Mg Ib/ton
3.5
7.5
6.5
69
18.5
15
3
17.5
3.5
4
7
15
13
138
37
30
6
35
7
8
Sulfur
kg/Mg
1.25
1.25
0.05
NA
1.25
0.25
0.25
0.25
0.25
Neg
oxidesb
Ib/ton
2.5f
2.5*
O.lJ
NA
2.5f
0.5
0.5
0.5
0.5
Keg
Carbon
kg/Mg
5
10
NA
NA
NA
10
5
150
Neg
Neg
monoxide
Ib/ton
10
20
NA
NA
NA
20
10
300
Neg
Neg
Volatile organicsc
kg/Mg
1.5
7.5
NA
NA
NA
7.5
1.5
50
1
Neg
Ib/ton
3
15
NA
NA
NA
15
3
100
2
Neg
Nitrogen oxidesd
kg/Mg
1.5
1
2
NA
NA
1.5
5
0.5
1
1.5
Ib/ton
3
2
4
NA
NA
3
10
1
2
3
w
s
I— I
CO
§
O
H
8
to
VD
O
^Factors are averages based on EPA procedures for incinerator stack testing. NA * not available. Neg *• negligible.
Expressed as St^.
^Expressed as methane.
Expressed as N02.
eReferences 6,10-13.
fBased on municipal incinerator data.
^References 6,10-11,13.
^Reference 8.
JBased on data for wood combustion in conical burners.
^References 6,11-15.
mWith afterburners and draft controls. References 6,13-14.
References 10-11.
PReference 10.
^Reference 6,16.
-------
the primary chamber by hydraulic transfer rams, oscillating grates or a
revolving hearth. Bottom ash is discharged to a wet quench pit.
The majority of combustion air is provided in the primary chamber. Up to
200 percent excess air can be supplied. Flue gas burnout occurs in the
secondary chamber, which is also refractory lined. Heat is recovered in waste
heat boilers.
Particulate emissions are typically controlled by ESPs , although other
controls including a cyclone and an electrified gravel bed, are used. A few
newer facilities have acid gas controls. Some modular excess air combustors
operate without emission controls.
Rotary Waterwall - This type of system uses a rotary combustion chamber
with pre- sorting of objects too large to fit in the combustor. The waste is
ram fed to the rotary combustion chamber, which sits at an angle and rotates
slowly, causing the waste to advance and tumble as it burns. Bottom ash is
discharged from the rotary combustor to a stationary after burning grate and
then into a wet quench pit .
Underfire air is injected through the waste bed and overfire air is
provided directly above the waste bed. Approximately 80 percent of the
combustion air is provided along the combustion chamber length with most of
this provided in the first half of the length. The rest of the combustion air
is supplied to the afterburner grate and above the rotary combustor outlet in
the boiler chamber. Water flowing through the tubes in the rotary chamber
recovers heat from combustion. Additional heat recovery occurs in the boiler
waterwall , superheater and economizer. Flue gas emissions are controlled by
ESPs or fabric filters.
Fluidized Bed - This technology is an alternative method of combusting
RDF. Fluffed or pelletized RDF is combusted on a turbulent bed of heated
noncombustible material such as limestone, sand, silica, or alumina. The bed
is suspended or "fluidized" through introduction of underfire air at a high
flow rate. Overfire air is used to complete combustion.
There are two basic types of fluidized bed combustion systems; bubbling
bed combustors and circulating fluidized bed combustors. With bubbling bed
combustors, most of the fluidized solids are maintained near the bottom of the
combustor by using relatively low air f luidization velocities . This helps
prevent the entrainment of solids from the bed into the flue gas, minimizing
recirculation or reinjection of bed particles. Circulating fluidized bed
combustors operate at relatively high fluidization velocities to promote carry
over of solids into the upper section of the combustor. Combustion occurs in
both the bed and upper section of the combustor. By design, a fraction of the
bed material is entrained in the combustion gas and enters a cyclone separator
which recycles unburned waste and inert particles to the lower bed.
2.1.1.2 Emissions And Controls
Refuse combustors have the potential to emit significant quantities of
pollutants to the atmosphere. The major pollutants emitted are: (1)
particulate matter, (2) metals (in solid form on particulate, except for
mercury), (3) acid gases (primarily hydrogen chloride [HC1] and sulfur dioxide
, (4) carbon monoxide (CO), (5) nitrogen oxides (NOX), and (6) toxic
9/90 Solid Waste Disposal 2.1-11
-------
U
OS
g
I
30
25
20
15
10
5
0
O.I
Uncontrolled
Controlled
i i i i 11
1.0 10
PirtlcU diMtttr (i«)
0.60
0.50 2
o
4J
O
CO
0.40
0.30 3
100
c
o
•H *-x
CD 00
0.20 %
•H
O
0.10 £
o
o
0
Figure 2.1-7. Cumulative particle size distribution and size
specific emission factors for refuse-derived fuel
combustors.
organic compounds (most notably chlorinated dibenzo-p-dioxins and chlorinated
dibenzo furans [CDD/CDF]) .
Particulate matter is emitted because of the turbulent movement of the
combustion gases with respect to the burning refuse and resultant ash.
Particulate matter is also produced when metals that are volatilized in the
combustion zone condense in the exhaust gas stream. The particle size
distribution and concentration of the particulate emissions leaving the
combustor vary widely, depending on the composition of the refuse being burned
and the type and operation of the combustor.
Particulate matter from MWCs contributes to hazardous air emissions in
two ways. First, trace metals are emitted because they are typically
concentrated in the smaller size fraction of the total particulate emissions
where capture is more difficult. Secondly, the amount of particulate surface
area may contribute to the availability of sites for catalytic reactions
involving toxic organic compounds, thus playing a role in potential downstream
formation mechanisms (see below).
Metals emissions are affected by two primary factors, (1) level of
particulate matter control, and (2) flue gas temperature. Most metals (with
the exception of mercury) are associated with fine particulate, and would
therefore be removed as the fine particulate are removed. Mercury is
generally not contained on particulate matter and removal is not a function of
particulate removal.
Concentrations of HC1 and S02 in MWC flue gases are directly related to
the quantities of chlorine and sulfur in the waste. Refuse components that
are major contributors of sulfur include rubber, plastics, foodwastes,
2.1-12
EMISSION FACTORS
9/90
-------
yardwastes, and paper. Similarly, plastics and miscellaneous organic
compounds are the major sources of chlorine in refuse. Therefore, chlorine
and sulfur contents can vary considerably based on seasonal and local waste
variations.
Carbon monoxide can be formed when insufficient oxygen is available for
complete combustion, or when excess air levels are too high, thus lowering
combustion temperature.
Nitrogen oxides are formed during combustion through (1) oxidation of
nitrogen in the waste and (2) fixation of atmospheric nitrogen. Conversion of
nitrogen in the waste occurs at relatively low temperatures (less than 1090°C
[2000°F]), while fixation of atmospheric of atmospheric nitrogen occurs at
higher temperatures. 75 to 80 percent of NOX formed is associated with
nitrogen in the waste.^
CDD/CDF may be formed through two mechanisms. In the first, CDD/CDF are
formed as products of reactions in the furnace when the combustion process
fails to completely convert hydrocarbons to carbon dioxide and water.
Alternatively, organic compounds which escape the high temperature regions of
the furnace may react at lower temperatures downstream to form CDD/CDF.
Formation of CDD/CDF across the ESP is a recently identified concern with the
operation of MWC ESPs at temperatures above roughly 230°C (450°F). The
mechanism and extent of formation are poorly understood.
A wide variety of control technologies are used to control emissions from
MWCs. For particulate control, electrostatic precipitators are most
frequently used, although other particulate control devices (including
electrified gravel beds, fabric filters, cyclones and venturi scrubbers) are
used. Processes used for acid gas control include wet scrubbing, dry sorbent
injection, and spray drying.
Electrostatic Precipitator - Particulate emissions from MWCs are most
often controlled using ESPs. In this process, flue gas flows between a series
of high voltage (20 to 100 kilovolts) discharge electrodes and grounded metal
plates. Negatively charged ions formed by this high voltage field (known as a
"corona") attach to PM in the flue gas, causing the charged particles to
migrate toward the grounded plates. Once the charged particles are collected
on the grounded plates, the resulting dust layer is removed from the plates by
rapping, washing, or some other method and collected in a hopper. When the
dust layer is removed, some of the collected PM becomes reentrained in the
flue gas. To assure good PM collection efficiency during plate cleaning and
electrical upsets, ESPs have several fields located in series along the
direction of flue gas flow that can be energized and cleaned independently.
Particles reentrained when the dust layer is removed from one field can be
recollected in a downstream field.
Small particles generally have lower migration velocities than large
particles, and are therefore more difficult to collect. This factor is
especially important to MWCs because of the large amount of total fly ash
smaller than one micron. As compared to pulverized coal fired combustors, in
which only 1 to 3 percent of the fly ash is generally smaller than 1 micron,
20 to 70 percent of the fly ash at the ESP inlet for MWCs is reported to be
smaller than 1 micron. As a result, effective collection of PM from MWCs
9/90 Solid Waste Disposal 2.1-13
-------
requires greater collection areas and lower flue gas velocities than many
other combustion types.
The most common types of ESPs used by MWCs are (1) plate wire units in
which the discharge electrode is a bottom weighted or rigid wire and (2) flat
plate units which use flat plates rather than wires as the discharge
electrode. Plate wire ESPs generally are better suited for use with fly ashes
with large amounts of small particulate and with large flue gas flow rates
(greater than 5700 actual cubic meters per minute [200,000 actual cubic feet
per minute]). Flat plate units are less sensitive to back corona problems and
are thus well suited for use with high resistivity PM. Both of these ESP
types have been widely used on MWCs in the U. S., Europe, and Japan.
As an approximate indicator of collection efficiency, the specific
collection area (SCA) of an ESP is frequently used. The SCA is calculated by
dividing the collecting electrode plate area by the actual flue gas flow rate
and is expressed as square feet of collecting area per 1000 actual cubic feet
per minute of flue gas. In general, the higher the SCA, the higher the
collection efficiency.
Fabric Filters - Fabric filters (baghouses) are frequently used in
combination with acid gas controls and are of two basic designs, reverse air
and pulse cleaned. Both methods provide additional potential for acid gas
removal as the filter cake builds up on the bags. In a reverse air fabric
filter, flue gas flows through unsupported filter bags, leaving the
particulate on the inside of the bags. The particulate builds up to form a
particulate filter cake. Once excessive pressure drop across the filter cake
is reached, air is blown through the filter in the opposite direction, the
filter bag collapses, and the filter cake falls off and is collected. In a
pulse cleaned fabric filter, flue gas flows through supported filter bags
leaving particulate on the outside of the bags. To remove built up
particulate filter cake, compressed air is introduced through the inside of
the filter bag, the filter bag expands and the filter cake falls off and is
collected. Particulate removal by a fabric filter following acid gas controls
is typically greater than 99 percent.
Wet Scrubbers - Many types of wet scrubbers are used for controlling acid
emissions from MWCs. These include spray towers, centrifugal scrubbers, and
venturi scrubbers. In these devices, the flue gas enters the absorber where
it is contacted with enough alkaline solution to saturate the gas stream. The
alkaline solution, typically containing calcium hydroxide [Ca(OH>2] reacts
with the acid gas to form salts, which are generally insoluble and may be
removed by sequential clarifying, thickening, and vacuum filtering. The
dewatered salts or sludges are then landfilled.
Dry Sorbent Injection - This type of technology has been developed
primarily to control acid gas emissions. However, when combined with flue gas
cooling and either a fabric filter or ESP, sorbent injection processes may
also control CDD/CDF and particulate emissions from MWCs. Two primary subsets
of dry sorbent injection technologies exist. The more widely used of these
approaches, referred to as duct sorbent injection (DSI), involves injecting
dry alkali sorbents into flue gas downstream of the combustor outlet and
upstream of the particulate control device. The second approach, referred to
as furnace sorbent injection (FSI), injects sorbent directly into the
combustor.
2.1-14 EMISSION FACTORS 9/90
-------
In DSI, powdered sorbent is pneumatically injected into either a separate
reaction vessel or a section of flue gas duct located downstream of the
combustor economizer or quench tower. Alkali in the sorbent (generally
calcium or sodium) reacts with HC1, hydrogen fluoride (HF), and SC>2 to form
alkali salts (e. g. , calcium chloride [CaC^], calcium fluoride [CaFo], and
calcium sulfite [CaSO^]). By lowering the acid content of the flue gas,
downstream equipment can be operated at reduced temperatures while minimizing
the potential for acid corrosion of equipment. Reaction products, fly ash,
and unreacted sorbent are collected with either a fabric filter or ESP.
Acid gas removal efficiency with DSI depends on flue gas temperature,
sorbent type and feed rate, and the extent of sorbent mixing with the flue
gas. Flue gas temperature at the point of sorbent injection can range froni
180 to 320°C (350 to 600°F) depending on the sorbent being used and the design
of the process. Sorbents that have been successfully tested include hydrated
lime (Ca(OH)2), soda ash (^2^3), and sodium bicarbonate (NaHCO-j). Based on
published data for hydrated lime, DSI can achieve relatively high removals of
HC1 (60 to 90 percent) and SC>2 (40 to 70 percent) under proper operating
conditions. Limestone (CaCO-j) has also been tested but is relatively
unreactive at the above temperatures.
By combining flue gas cooling with DSI, it may be possible to increase
the potential for CDD/CDF removal which is believed to occur through a
combination of vapor condensation and adsorption onto the sorbent surface.
Cooling may also benefit PM control by decreasing the effective flue gas flow
rate (i. e., actual cubic meters per minute) and reducing the resistivity of
individual particles.
Furnace sorbent injection involves the injection of powdered alkali
sorbent into the furnace section of a combustor. This can be accomplished by
addition of sorbent to the overfire air, injection through separate ports, or
mixing with the waste prior to feeding to the combustor. As with DSI,
reaction products, flyash, and unreacted sorbent are collected using a fabric
filter or ESP.
The basic chemistry of FSI is similar to DSI. Both use a reaction of
sorbent with acid gases to form alkali salts. However, several key
differences exist in these two approaches. First, by injecting sorbent
directly into the furnace (at temperatures of 870 to 1200°C [1600 to 2200°F])
limestone can be calcined in the combustor to more reactive lime, thereby
allowing use of less expensive limestone as a sorbent. Second, at these
temperatures, S02 and lime react in the combustor, thus providing a mechanism
for effective removal of S02 at relatively low sorbent feed rates. Third, by
injecting sorbent into the furnace rather than into a downstream duct,
additional time is available for mixing and reaction between the sorbent and
acid gases. As a result, it may be possible to remove HCl and S02 from the
flue gas at lower sorbent-to-acid gas stoichiometric ratios than with DSI.
Fourth, if a significant portion of the HCl is removed before the flue gas
exits the combustor, it may be possible to reduce the formation of CDD/CDF in
latter sections of the flue gas ducting. However, HCl and lime do not react
with each other at temperatures above 760°C (1,400°F).
Spray Drying - Spray drying is designed to control S02 and HCl emissions.
When used in combination with particulate control, the system can control
CDD/CDF, PM, S02, and HCl emissions from MWCs. In the spray drying process,
9/90 Solid Waste Disposal 2.1-15
-------
lime slurry is injected into a spray dryer (SD). The water in the slurry
evaporates to cool the flue gas and the lime reacts with acid gases to form
salts that can be removed by a PM control device. The simultaneous
evaporation and reaction increases the moisture and particulate content in the
flue gas. The particulate leaving the SD contains fly ash plus calcium salts,
water, and unreacted lime.
The key design and operating parameters that significantly affect SD
performance are SD outlet temperature and lime-to-acid gas stoichiometric
ratio. The SD outlet temperature is controlled by the amount of water in the
slurry. More effective acid gas removal occurs at lower temperatures, but the
temperature must be high enough to ensure the slurry and reaction products are
adequately dried prior to collection in the PM control device. For MWC flue
gas containing significant chlorine, a minimum SD outlet temperature of around
120°C (240°F) is required to control agglomeration of PM and sorbent by
calcium chloride. The stoichiometric ratio is the molar ratio of calcium fed
to the theoretical amount of calcium required to react with the inlet HC1 and
SC>2- Lime is fed in quantities sufficient to react with the peak acid gas
concentrations expected without severely decreasing performance. The lime
content in the slurry must be maintained at or below approximately 30 percent
by weight to prevent clogging of the lime slurry feed system and spray
nozzles.
Spray drying can be used in combination with either a fabric filter or an
ESP for PM control. Both combinations have been used for MWCs in the United
States, although SD/fabric filter systems are more common. Typical removal
efficiencies range from 50 to 90 percent for SC>2 and for 70 to 95 percent for
HC1.
Emission factors for municipal waste cumbustors are shown in Table 2.1-1.
Table 2.1-2 shows the cumulative particle size distribution and size specific
emission factors for municipal waste combustors. Figures 2.1-5, 2.1-6 and
2.1-7 show the cumulative particle size distribution and size specific
emission factors for mass burn, starved air and RDF combustors, respectively.
2.1.2 Other Types Of Combustors8"11
The most common types of combustors consist of a refractory-lined
chamber with a grate upon which refuse is burned. In some newer
incinerators water-walled furnaces are used. Combustion products are formed
by heating and burning of refuse on the grate. In most cases, since
insufficient underfire (undergrate) air is provided to enable complete
combustion, additional over-fire air is admitted above the burning waste to
promote complete gas-phase combustion. In multiple-chamber incinerators,
gases from the primary chamber flow to a small secondary-mixing chamber
where more air is admitted, and more complete oxidation occurs. As much as
300 percent excess air may be supplied in order to promote oxidation of
combustibles. Auxilliary burners are sometimes installed in the mixing
chamber to increase the combustion temperature. Many small-size incin-
erators are single-chamber units in which gases are vented from the primary
combustion chamber directly into the exhaust stack. Single-chamber
incinerators of this type do not meet modern air pollution codes.
2.1-16 EMISSION FACTORS 9/90
-------
2.1.2.1 Process Description8"11 .,„ /
Industrial/commercial Combustors - The capacities of these units cover a
wide range, generally between 22.7 and 1800 kilograms (50 and 4000 pounds)
per hour. Of either single- or multiple-chamber design, these units are
often manually charged and intermittently operated. Some industrial
combustors are similar to municipal combustors in size and design. Better
designed emission control systems include gas-fired afterburners, scrubbers,
or both.
Trench Combustors - A trench combustor is designed for the combustion of
wastes having relatively high heat content and low ash content. The design
of the unit is simple. A U-shaped combustion chamber is formed by the sides
and bottom of the pit, and air is supplied from nozzles (or fans) along the
top of the pit. The nozzles are directed at an angle below the horizontal
to provide a curtain of air across the top of the pit and to provide air for
combustion in the pit. Low construction and operating costs have resulted
in the use of this combustor to dispose of materials other than those for
which it was originally designed. Emission factors for trench combustors
used to burn three such materials are included in Table 2.1-4.
Domestic Combustors - This category includes combustors marketed for
residential use. Fairly simple in design, they may have single or multiple
chambers and usually are equipped with an auxiliary burner to aid
combustion.
Flue-fed Combustors - These units, commonly found in large apartment
houses, are characterized by the charging method of dropping refuse down the
combustor flue and into the combustion chamber. Modified flue-fed
incinerators utilize afterburners and draft controls to improve combustion
efficiency and reduce emissions.
Pathological Combustors - These are combustors used to dispose of animal
remains and other organic material of high moisture content. Generally,
these units are in a size range of 22.7 to 45.4 kilograms (50 to 100 pounds)
per hour. Wastes are burned on a hearth in the combustion chamber. The
units are equipped with combustion controls and afterburners to ensure good
combustion and minimal emissions.
2.1.2.2 Emissions And Controls8
Operating conditions, refuse composition, and basic combustor design
have a pronounced effect on emissions. The manner in which air is supplied
to the combustion chamber or chambers has a significant effect on the
quantity of particulate emissions. Air may be introduced from beneath the
chamber, from the side, or from the top of the combustion chamber. As
underfire air is increased, an increase in fly-ash emissions occurs.
Erratic refuse charging causes a disruption of the combustion bed and a
subsequent release of large quantities of particulates. Large quantities of
uncombusted particulate matter and carbon monoxide are also emitted for an
extended period after charging of batch-fed units because of interruptions
in the combustion process. In continuously fed units, furnace particulate
emissions are strongly dependent upon grate type. The use of a rotary kiln
and reciprocating grates results in higher particulate emissions than the
use of a rocking or traveling grate. Emissions of oxides of sulfur are
9/90 Solid Waste Disposal 2.1-17
-------
00
TABLE 2.1-4. UNCONTROLLED EMISSION FACTORS FOR REFUSE COHBUSTORS OTHER THAN MUNICIPAL WASTE9
EMISSION FACTOR RATING: A
Partlculate
w
s
to
to
1— 1
o
25
T)
O
H
O
Incinerator type
Industrlal/cowKrclal
Multiple charters*
Single charter9
Trenehh
Wood
Rubber tires
Municipal refuse
Flue-fed single chamber*
Flue-fed (Bodlfled)1'*
Domestic single chamber
Without pHiary burner"
With priaary burner0
Pathological1*
Ib/ton
7
IS
13
138
37
30
6
35
7
8
kg/NT
3.5
7.5
6.5
69
18.5
15
3
17.5
3.5
4
Sulfur oxidesb
Ib/ton
2.5'
2.5'
0.11
1
2.5'
0.5
0.5
0.5
0.5
Neg.
kg/MT
1.25
1.25
0.05
J
1.25
0.25
0.25
0.25
0.25
Neg.
Carton aonoxlde
Ib/ton kg/St
10
20
j
J
j
20
10
300
Neg.
Neg.
5
10
J
J
j
10
s
ISO
Neg.
Neg.
Hydrocarbons'
Ib/ton
3
IS
J
J
j
15
3
100
2
Neg.
kg/NT
1.5
7.5
J
j
J
7.5
1.5
SO
1
Neg.
Nitrogen o»ldesd
Ib/ton kg^lT
3
2
4
J
j
3
10
1
2
3
1.5
1
2
J
J
1.5
5
0.5
1
l.S
aAverage factors, based on EPA procedures for incinerator stack testing. Neg = negligible.
Expressed as sulfur dioxide.
Expressed as methane.
Expressed as nitrogen dioxide.
^References 3, 7-10.
fBased on municipal incinerator data.
^References 5, 7-8, 10.
.Reference 5.
1Based on data for wood combustion in conical burners.
VO
O
available.
^References 3, 8-12.
AWith afterburners and draft controls.
""References 3, 10-11.
"References 7-8.
Reference 7.
PReferences 3, 13.
-------
dependent on the sulfur content of the refuse. Carbon monoxide and unburned
hydrocarbon emissions may be significant and are caused by poor combustion
resulting from improper combustor design or operating conditions. Nitrogen
oxide emissions increase with an increase in the temperature of the
combustion zone, an increase in the residence time in the combustion zone
before quenching, and an increase in the excess air rates to the point where
dilution cooling overcomes the effect of increased oxygen concentration. ^
References for Section 2.1
1. Municipal Waste Combustion Industry Profile - Facilities Subject To
Section llKd) Guidelines. Radian Corporation, Research Triangle Park,
NC, prepared for U. S. Environmental Protection Agency, September 16,
1988.
2. Municipal Waste Combustion Study - Combustion Control Of Organic
Emissions. EPA/530-SW-87-021-C, U. S. Environmental Protection Agency,
Research Triangle Park, NC, June 1987, p. 6-2.
3. Municipal Waste Combustion Retrofit Study (Draft), Radian Corporation,
Research Triangle Park, NC, prepared for U. S. Environmental Protection
Agency, August 5, 1988, p. 6-4.
4. Air Pollution Control At Resource Recovery Facilities. California Air
Resources Board, Sacramento, CA, May 24, 1984.
5. Control Of NOX Emissions from Municipal Waste Combustors. Radian
Corporation, Research Triangle Park, NC, prepared for U. S.
Environmental Protection Agency, February 3, 1989.
6. H. Vogg and L. Stieglitz, Chemosphere. Volume 15, 1986.
7. Emission Factor Documentation For AP-42 Section 2.1.1: Municipal Waste
Combustion. EPA-450/4-90-016, U. S. Environmental Protection Agency,
Research Triangle Park, NC, August 1990.
8. Air Pollutant Emission Factors. APTD-0923, U. S. Environmental
Protection Agency, Research Triangle Park, NC, April 1970.
9. Control Techniques For Carbon Monoxide Emissions From Stationary
Sources. AP-65, U. S. Environmental Protection Agency, Research Triangle
Park, NC, March 1970.
10. Air Pollution Engineering Manual. AP-40, U. S. Environmental Protection
Agency, Research Triangle Park, NC, 1967.
11. J. DeMarco. et al.. Incinerator Guidelines 1969. SW. 13TS, U. S.
Environmental Protection Agency, Research Triangle Park, NC, 1969.
12. J. 0. Brukle, J. A. Dorsey, and B. T. Riley, "The Effects Of Operating
Variables And Refuse Types On Emissions From A Pilot-scale Trench
Incinerator", Proceedings Of The 1968 Incinerator Conference. American
Society Of Mechanical Engineers, New York, NY, May 1968.
9/90 Solid Waste Disposal 2.1-19
-------
13. Walter R. Nessen, Systems Study Of Air Pollution From Municipal
Incineration. Contract Number CPA-22-69-23, Arthur D. Little, Inc.
Cambridge, MA, March 1970.
14. C. V. Kanter, R. G. Lunche, and A. P. Fururich, "Techniques For Testing
Air Contaminants From Combustion Sources", Journal Of The Air Pollution
Control Association. 6(4): 191-199, February 1957.
15. J. L. Stear, Municipal Incineration: A Review Of Literature. AP-79, U.
S. Environmental Protection Agency, Research Triangle Park, NC, June
1971.
16. E. R. Kaiser, Refuse Reduction Processes In Proceedings Of Surgeon
General's Conference On Solid Waste Management. PHS 1729, Public Health
Service, Washington, DC, 1967.
17. Unpublished source test data on incinerators, Resources Research,
Incorporated, Reston, VA, 1966-1969.
18. E. R. Kaiser, et al. . Modifications To Reduce Emissions From A Flue-fed
Incinerator. Report Number 552.2, College Of Engineering, New York
University, June 1959, pp. 40 and 49.
19. Communication between Resources Research, Incorporated, Reston, VA, and
Division Of Air Quality Control, Maryland State Department Of Health,
Baltimore, MD, 1969.
20. Unpublished data on incinerator testing, U. S. Environmental Protection
Agency, Research Triangle Park, NC, 1970.
2.1-20 EMISSION FACTORS 9/90
-------
2.5 SEWAGE SLUDGE INCINERATION
There are currently almost 200 sewage sludge incineration (SSI) plants
in operation in the United States. Three main types of incinerators are used:
multiple hearth, fluidized bed, and electric infrared. Some sludge is co-
fired with municipal solid waste in combustors based on refuse combustion
technology. Refuse co-fired with sludge in combustors based on sludge
incinerating technology is limited to multiple hearth incinerators only.
Over 80 percent of the identified operating sludge incinerators are of
the multiple hearth design. About 15 percent are fluidized bed combustors and
3 percent are electric. The remaining combustors co-fire refuse with sludge.
Most sludge incinerators are located in the Eastern United States, though
there are a significant number on the West Coast. New York has the largest
number of facilities with 28. Pennsylvania and Michigan have the next-largest
numbers of facilities with 20 and 19 sites, respectively.
2.5.1 Process Description-*--^
Types of incineration described in this section include:
Multiple hearth
Fluidized bed
Electric
Single hearth cyclone
Rotary kiln
High pressure, wet air oxidation
Co-incineration with refuse
2.5.1.1 Multiple Hearth Furnaces
The multiple hearth furnace was originally developed for mineral ore
roasting nearly a century ago. The air-cooled variation has been used to
incinerate sewage sludge since the 1930s. A cross section diagram of a
typical multiple hearth furnace is shown in Figure 2.5-1. The basic multiple
hearth furnace (MHF) is cylinder shaped and oriented vertically. The outer
shell is constructed of steel, lined with refractory, and surrounds a series
of horizontal refractory hearths. A hollow cast iron rotating shaft runs
through the center of the hearths. Cooling air is introduced into the shaft
by a fan located at its base. Attached to the central shaft are rabble arms,
which extend above the hearths. Each rabble arm is equipped with a number of
teeth, approximately 6 inches in length, and spaced about 10 inches apart.
The teeth are shaped to rake the sludge in a spiral motion, alternating in
direction from the outside in, to the inside out, between hearths. Typically,
the upper and lower hearths are fitted with 4 rabble arms, and the middle
hearths are fitted with two. Burners, providing auxiliary heat, are located
in the sidewalls of the hearths.
9/90 Solid Waste Disposal 2.5-1
-------
COOLING AIR •
DISCHARGE
X|\ SLUDGE -,
•r^Sl
-BURNERS
-SUPPLEMENTAL
FUEL
' • COMBUSTION AIR
SHAFT COOLING
AIR RETURN
SOLIDS FLOW
DROP HOLES
DISCHARGE
Figure 2.5-1. Cross section of a multiple hearth furnace.
»• EXHAUST AND ASH
PRESSURE TAP
SIGHT
GLASS
BURNER
PRESSURE TAP
2.5-2
Figure 2.5-2. Cross section of a fluidized bed furnace
EMISSION FACTORS
9/90
-------
Partially dewatered sludge is fed onto the perimeter of the top
hearth. The motion of the rabble arms rakes the sludge toward the center
shaft where it drops through holes located at the center of the hearth. In
the next hearth the sludge is raked in the opposite direction. This proqess
is repeated in all of the subsequent hearths. The effect of the rabble motion
is to break up solid material to allow better surface contact with heat and
oxygen, and is arranged so that sludge depth of about one inch is maintained
in each hearth at the design sludge flow rate.
Scum may also be fed to one or more hearths of the incinerator. Scum
is the material that floats on wastewater. It is generally composed of
vegetable and mineral oils, grease, hair, waxes, fats, and other materials
that will float. Scum may be removed from many treatment units including
preaeration tanks, skimming tanks, and sedimentation tanks. Quantities of
scum are generally small compared to those of other wastewater solids.
Ambient air is first ducted through the central shaft and its
associated rabble arms. A portion, or all, of this air is then taken from the
top of the shaft and recirculated into the lowermost hearth as preheated
combustion air. Shaft cooling air which is not circulated back into the
furnace is ducted into the stack downstream of the air pollution control
devices. The combustion air flows upward through the drop holes in the
hearths, countercurrent to the flow of the sludge, before being exhausted from
the top hearth. Provisions are usually made to inject ambient air directly
into on the middle hearths as well.
From the standpoint of the overall incineration process, multiple
hearth furnaces can be divided into three zones. The upper hearths comprise
the drying zone where most of the moisture in the sludge is evaporated. The
temperature in the drying zone is typically between 425 and 760°C (800 and
1400°F). Sludge combustion occurs in the middle hearths (second zone) as the
temperature is increased to about 925°C (1700°F). The combustion zone can be
further subdivided into the upper middle hearths where the volatile gases and
solids are burned, and the lower middle hearths where most of the fixed carbon
is combusted. The third zone, made up of the lowermost hearth(s), is the
cooling zone. In this zone the ash is cooled as its heat is transferred to
the incoming combustion air.
Multiple hearth furnaces are sometimes operated with afterburners to
further reduce odors and concentrations of unburned hydrocarbons. In
afterburning, furnace exhaust gases are ducted to a chamber where they are
mixed with supplemental fuel and air and completely combusted. Some
incinerators have the flexibility to allow sludge to be fed to a lower hearth,
thus allowing the upper hearth(s) to function essentially as an afterburner.
Under normal operating conditions, 50 to 100 percent excess air must
be added to a MHF in order to ensure complete combustion of the sludge.
Besides enhancing contact between fuel and oxygen in the furnace, these
relatively high rates of excess air are necessary to compensate for normal
variations in both the organic characteristics of the sludge feed and the rate
at which it enters the incinerator. When an inadequate amount of excess air
is available, only partial oxidation of the carbon will occur with a resultant
increase in emissions of carbon monoxide, soot, and hydrocarbons. Too much
excess air, on the other hand, can cause increased entrainment of particulate
and unnecessarily high auxiliary fuel consumption.
9/90 Solid Waste Disposal 2.5-3
-------
Some MHFs have been designed to operate in a starved air mode.
Starved air combustion (SAC) is, in effect, incomplete combustion. The key to
SAC is the use of less than theoretical quantities of air in the furnace,
30 to 90 percent of stoichiometric quantities. This makes SAC more fuel
efficient than an excess air mode MHF. The SAC reaction products are
combustible gases, tars and oils, and a solid char that can have appreciable
heating value. The most effective utilization of these products is by burning
of the total gas stream with subsequent heat recovery. When an SAC MHF is
combined with an afterburner, an overall excess air rate of 25 to 50 percent
can be maintained (as compared to 75 to 200 percent overall for an excess air
MHF with an afterburner).
Multiple hearth furnace emissions are usually controlled by a venturi
scrubber, an impingement tray scrubber, or a combination of both. Wet
cyclones are also used.
2.5.1.2 Fluidized Bed Incinerators
Fluidized bed technology was first developed by the petroleum industry
to be used for catalyst regeneration. Figure 2.5-2 shows the cross section
diagram of a fluidized bed furnace. Fluidized bed furnaces (FBF) are
cylindrically shaped and oriented vertically. The outer shell is constructed
of steel, and is lined.with refractory. Tuyeres (nozzles designed to deliver
blasts of air) are located at the base of the furnace within a refractory-
lined grid. A bed of sand, approximately 0.75 meters (2.5 feet) thick, rests
upon the grid. Two general configurations can be distinguished on the basis
of how the fluidizing air is injected into the furnace. In the "hot windbox"
design the combustion air is first preheated by passing through a heat
exchanger where heat is recovered from the hot flue gases. Alternatively,
ambient air can be injected directly into the furnace from a cold windbox.
Partially dewatered sludge is fed .into the lower portion of the
furnace. Air injected through the tuyeres, at pressure of from 20 to
35 kilopascals (3 to 5 pounds per square inch grade), simultaneously fluidizes
the bed of hot sand and the incoming sludge. Temperatures of 750 to 925°C
(1400 to 1700°F) are maintained in the bed. Residence times are on the order
of 2 to 5 seconds. As the sludge burns, fine ash particles are carried out
the top of the furnace. Some sand is also removed in the air stream; sand
make-up requirements are on the order of 5 percent for every 300 hours of
operation.
The overall process of combustion of the sludge occurs in two zones.
Within the bed itself (zone 1) evaporation of the water and pyrolysis of the
organic materials occur nearly simultaneously as the temperature of the sludge
is rapidly raised. In the second zone, (freeboard area) the remaining free
carbon and combustible gases are burned. The second zone functions
essentially as an after burner.
Fluidization achieves nearly ideal mixing between the sludge and the
combustion air and the turbulence facilitates the transfer of heat from the
hot sand to the sludge. The most noticeable impact of the better burning
atmosphere provided by a fluidized bed incinerator is seen in the limited
amount of excess air required for complete combustion of the sludge. These
incinerators can achieve complete combustion with 20 to 50 percent excess air,
about half the amount of excess air typically required for incinerating sewage
2.5-4 EMISSION FACTORS 9/90
-------
sludge in multiple hearth furnaces. As a consequence, FBF incinerators have
generally lower fuel requirements compared to MHF incinerators.
Fluidized bed incinerators most often have venturi scrubbers or
venturi/impingement tray scrubber combinations for emissions control.
2.5.1.3 Electric Incinerators
Electric furnace technology is new compared to other sludge combustor
designs; the first electric furnace was installed in 1975. Electric
incinerators consist of a horizontally oriented, insulated furnace. A woven
wire belt conveyor extends the length of the furnace and infrared heating
elements are located in the roof above the conveyor belt. Combustion air is
preheated by the flue gases and is injected into the discharge end of the
furnace. Electric incinerators consist of a number of prefabricated modules,
which can be linked together to provide the necessary furnace length. A cross
section of an electric furnace is shown in Figure 2.5-3.
The dewatered sludge cake is conveyed into one end of the incinerator.
An internal roller mechanism levels the sludge into a continuous layer
approximately one inch thick across the width of the belt. The sludge is
sequentially dried and then burned as it moves beneath the infrared heating
elements. Ash is discharged into a hopper at the opposite end of the furnace.
The preheated combustion air enters the furnace above the ash hopper and is
further heated by the outgoing ash. The direction of air flow is
countercurrent to the movement of the sludge along the conveyor. Exhaust
gases leave the furnace at the feed end. Excess air rates vary from 20 to
70 percent.
When compared to MHF and FBF technologies, the electric furnace offers
the advantage of lower capital cost, especially for smaller systems. However,
electricity costs in some areas may make an electric furnace infeasible. One
other concern is replacement of various components such as the woven wire belt
and infrared heaters, which have 3 to 5 year lifetimes.
Electric incinerators are usually controlled with a venturi scrubber
or some other wet scrubber.
2.5.1.4 Other Technologies
A number of other technologies have been used for incineration of
sewage sludge including cyclonic reactors, rotary kilns and wet oxidation
reactors. These processes are not in widespread use in the United States and
will be discussed only briefly.
The cyclonic reactor is designed for small capacity applications. It
is constructed of a vertical cylindrical chamber that is lined with
refractory. Preheated combustion air is introduced into the chamber
tangentially at high velocities. The sludge is sprayed radially toward the
hot refractory walls. Combustion is rapid: the residence time of the sludge
in the chamber is on the order of 10 seconds. The ash is removed with the
flue gases.
Rotary kilns are also generally used for small capacity applications.
The kiln is inclined slightly from the horizontal plane, with the upper end
9/90 Solid Waste Disposal 2.5-5
-------
receiving both the sludge feed and the combustion air. A burner is located at
the lower end of the kiln. The circumference of the kiln rotates at a speed
of about 6 inches per second. Ash is deposited into a hopper located below
the burner.
The wet oxidation process is not strictly one of incineration; it
instead utilizes oxidation at elevated temperature and pressure in the
presence of water (flameless combustion). Thickened sludge, at about six
percent solids, is first ground and mixed with a stoichiometric amount of
compressed air. The slurry is then pressurized. The mixture is then
circulated through a series of heat exchangers before entering a pressurized
reactor. The temperature of the reactor is held between 175 and 315°C
(350 and 600°F). The pressure is normally 7000 to 12,500 kilopascals (1000 to
1800 pounds per square grade). Steam is usually used for auxiliary heat.
The water and remaining ash are circulated out the reactor and are finally
separated in a tank or lagoon. The liquid phase is recycled to the treatment
plant. Off-gases must be treated to eliminate odors: wet scrubbing,
afterburning or carbon absorption may be used.
2.5.1.5 Co-incineration With Refuse
Wastewater treatment plant sludge generally has a high water content
and in some cases, fairly high levels of inert materials. As a result, its
net fuel value is often low. If sludge is combined with other combustible
materials in a co-combustion scheme, a furnace feed can be created that has
both a low water concentration and a heat value high enough to sustain
combustion with little or no supplemental fuel.
Virtually any material that can be burned can be combined with sludge
in a co-combustion process. Common materials for co-combustion are coal,
municipal solid waste (MSW), wood waste and agricultural waste. Thus, a
municipal or industrial waste can be disposed of while providing an autogenous
(self-sustaining) sludge feed, thereby solving two disposal problems.
There are two basic approaches to combusting sludge with municipal
solid waste, 1) use of MSW combustion technology by adding dewatered or dried
sludge to the MSW combustion unit, and 2) use of sludge combustion technology
by adding processed MSW as a supplemental fuel to the sludge furnace. With
the latter, MSW is processed by removing noncombustibles, shredding, air
classifying, and screening. Waste that is more finely processed is less
likely to cause problems such as severe erosion of the hearths, poor
temperature control, and refractory failures.
2.5.2 Emissions And Controls^"-*
Sewage sludge incinerators potentially emit significant quantities of
pollutants. The major pollutants emitted are: 1) particulate matter,
2) metals, 3) carbon monoxide (CO), 4) nitrogen oxides (NOX), 5) sulfur
dioxide (S02) and 6) unburned hydrocarbons. Partial combustion of sludge can
result in emissions of intermediate products of incomplete combustion (PIC)
including toxic organic compounds.
t
Uncontrolled particulate emission rates vary widely depending on the
type of incinerator, the volatiles and moisture content of the sludge, and the
operating practices employed. Generally, uncontrolled particulate emissions
2.5-6 EMISSION FACTORS 9/90
-------
HAULING
OCVICE
RADIANT
INFRARED
HEATING
ELEMENTS ITYPI
• WOVEN WIRE
CONTINUOUS IELT
COOLING
AIR
COOLING
AIR
COMMOTION
. OftCHAROC
Figure 2.5-3. Cross section of an electric infrared furnace.
Figure 2.5-4. Venturi/impingement tray scrubber.
9/90
Solid Waste Disposal
2.5-7
-------
are highest from fluidized bed incinerators because suspension burning results
in much of the ash being carried out of the incinerator with the flue gas.
Uncontrolled emissions from multiple hearth and fluidized bed incinerators are
extremely variable, however. Electric incinerators appear to have the lowest
rates of uncontrolled particulate release of the three major furnace types,
possibly because the sludge is not disturbed during firing. In general,
higher airflow rates increase the opportunity for particulate matter to be
entrained in the exhaust gases. Sludge with low volatile content or high
moisture content may compound this situation by requiring more supplemental
fuel to burn. As more fuel is consumed, the amount of air flowing through the
incinerator is also increased. However, no direct correlation has been
established between air flow and particulate emissions.
Metals emissions are affeqted by flue gas temperature and the level of
particulate matter control, since metals which are volatilized in the
combustion zone condense in the exhaust gas stream. Most metals (except
mercury) are associated with fine particulate and are removed as the fine
particulates are removed.
Carbon monoxide is formed when available oxygen is insufficient for
complete combustion or when excess air levels are too high, resulting in lower
combustion temperatures.
Nitrogen and sulfur oxide emissions are primarily the result of
oxidation of nitrogen and sulfur in the sludge. Therefore, these emissions
can vary greatly based on local and seasonal sewage characteristics.
Emissions of volatile organic compounds also vary greatly with
incinerator type and operation. Incinerators with countercurrent air flow
such as multiple hearth designs provide the greatest opportunity for unburned
hydrocarbons to be emitted. In the MHF, hot air and wet sludge feed are
contacted at the top of the furnace. Any compounds distilled from the solids
are immediately vented from the furnace" at temperatures too low to completely
de s true t them.
Particulate emissions from sewage sludge incinerators have
historically been controlled by wet scrubbers, since the associated sewage
treatment plant provides both a convenient source and a good disposal option
for the scrubber water. The types of existing sewage sludge incinerator
controls range from low pressure drop spray towers and wet cyclones to higher
pressure drop venturi scrubbers and venturi/impingement tray scrubber
combinations. A few electrostatic precipitators are employed, primarily where
sludge is co-fired with municipal solid waste. The most widely used control
device applied to a multiple hearth incinerator is the impingement tray
scrubber. Older units use the tray scrubber alone while combination
venturi/impingement tray scrubbers are widely applied to newer multiple hearth
incinerators and to fluidized bed incinerators. Most electric incinerators
and many fluidized bed incinerators use venturi scrubbers only.
In a typical combination venturi/impingement tray scrubber (shown in
Figure 2.5-4), hot gas exits the incinerator and enters the precooling or
quench section of the scrubber. Spray nozzles in the quench section cool the
incoming gas and the quenched gas then enters the venturi section of the
control device.
2.5-8 EMISSION FACTORS 9/90
-------
Venturi water is usually pumped into an inlet weir above the quencher.
The venturi water enters the scrubber above the throat and floods the throat
completely. This eliminates build-up of solids and reduces abrasion.
Turbulence created by high gas velocity in the converging throat section
deflects some of the water traveling down the throat into the gas stream.
Particulate matter carried along with the gas stream impacts on these water
particles and on the water wall. As the scrubber water and flue gas leave the
venturi section, they pass into a flooded elbow where the stream velocity
decreases, allowing the water and gas to separate. Most venturi sections come
equipped with variable throats. By restricting the throat area within the
venturi, the linear gas velocity is increased and the pressure drop is
subsequently increased. Up to a certain point, increasing the venturi
pressure drop increases the removal efficiency. Venturi scrubbers typically
maintain 60 to 99 percent removal efficiency for particulate matter, depending
on pressure drop and particle size distribution.
At the base of the flooded elbow, the gas stream passes through a
connecting duct to the base of the impingement tray tower. Gas velocity is
further reduced upon entry to the tower as the gas stream passes upward
through the perforated impingement trays. Water usually enters the trays from
inlet ports on opposite sides and flows across the tray. As gas passes
through each perforation in the tray, it creates a jet which bubbles up the
water and further entrains solid particles. At the top of the tower is a mist
eliminator to reduce the carryover of water droplets in the stack effluent
gas. The impingement section can contain from one to four trays, but most
systems for which data are available have two or three trays.
Emission factors and emission factor ratings for sludge incinerators
are shown in Table 2.5-1. Table 2.5-2 shows the cumulative particle size
distribution and size specific emission factors for sewage sludge
incinerators. Figures 2.5-5, 2.5-6, and 2.5-7 show cumulative particle size
distribution and size-specific emission factors for multiple-hearth,
fluidized-bed, and electric infrared incinerators, respectively.
9/90 Solid Waste Disposal 2.5-9
-------
ro
Ln
i
l-1
a
m
S
00
i— i
O
Tl
n
H
TAULt i.5-l
.. raic&iiw
Multiple hearth
Pollutant.
Particulate
Total
particulate
Lead
Sulfur dioxide*
Nitrogen oxides
Carbon monoxide
Volatile
organics
Methane
Nonmethane
Cut Uncontrolled,
diameter, kg/Mg
microns (Ib/ton)
0.625 0.30 (0.60)
1.0 0.47 (0.94)
2.5 1.1 (2.2)
5.0 2.1 (4.2)
10.0 4.1 (8.2)
15.0 6.0 (12)
42 (84)
0.05 (0.10)
10 (20)
5.5 (11)
36 (72)
NA
0.85 (1.7)
After
scrubber,
kg/Mg
( Ib/ton )*>
0.07 (0.14)c
0.08 (0.16)
0.09 (0.18)
0.10 (0.20)
0.11 (0.22)
0.12 (0.24)
0.89 (1.8)e
0.02 (0.04)e
2(4)6
2.5 (5.0)e
2(4)e
2.3 (4.6)e
0.85 (1.7)e
Emission
Factor
Rating
E
C
C
D
C
C
D
D
1 fflUUC HUK 5EV
HttjC SLUlit INUM
iKfllUKT
Fluidized bed
Uncontrolled,
kg/Mg
(lb/tonr
NA
NA
NA
10 (20)
NA
NA
NA
NA
After
scrubber,
kg/Mg
( Ib/ton y
0.08 (0.16)d
0.15 (0.30)
0.18 (0.36)
0.20 (0.40)
0.22 (0.44)
0.23 (0.46)
0.33 (0.66)e
0.003 (0.006)6
2.0 (4.0)e
2.2 (4.4)e
2(4)e
l(2)e
NA
Emission
Factor
Rating
E
C
D
D
D
E
E
Uncontrolled,
kg/Mg
(Ib/ton)15
0.50 (1.0)
0.60 (1.2)
1.0 (2.0)
1.7 (3.4)
3.0 (6.0)
4.3 (8.6)
4(8)
NA
10 (20)
4(8)
NA
NA
NA
Electric infrared
After
scrubber,
kg/Mg
(lb/ton)D
0.30 (0.60)e
0.35 (0.70)
0.50 (1.0)
0.70 (1.4)
1.0 (2.0)
1.2 (2.4)
l(2)e
NA
2.0 (4.0)e
3(6)e
NA
NA
NA
Emission
Factor
Rating
E
E
D
E
^Reference 5. NA = not available.
^Expressed in units of dried sludge. Particulate figures in parentheses are cumulative.
clmpingement scrubber.
VO
o
Venturi scrubber.
^Impingement, venturi and/or cyclone scrubbers.
Because data were limited, an average for all three types of incinerators is presented.
-------
TABLE 2.5-2. CUMULATIVE PARTICLE SIZE DISTRIBUTION AND SIZE SPECIFIC
EMISSION FACTORS FOR SEWAGE SLUDGE INCINERATORSa
Particle Cumulative mass % < stated size Cumulative emission
size.
microns
15
10
5.0
2.5
1.0
0.625
TOTAL
Uncontrolled Controlled Uncontrolled
MHD FBC El° MH° FBC El° MHD FBC Ela
15 NA 43 30 7.7 60 6.0 NA 4.3
(12) (8.6)
10 NA 30 27 7.3 50 4.1 NA 3.0
(8.2) (6.0)
5.3 NA 17 25 6.7 35 2.1 NA 1.7
(4.2) (3.4)
2.8 NA 10 22 6.0 25 1.1 NA 1.0
(2.2) (2.0)
1.2 NA 6.0 20 5.0 18 0.47 NA 0.60
(0.94) (1.2)
0.75 NA 5.0 17 2.7 15 0.30 NA 0.50
(0.60) (1.0)
100 100 100 100 100 100 40 NA 10
(80) (20)
factor, kg/Mg (Ib/ton)
Control led
MHD FBP
0.12 0.23
(0.24) (0.46)
0.11 0.22
(0.22) (0.44)
0.10 0.20
(0.20) (0.40)
0.09 0.18
(0.18) (0.36)
0.08 0.15
(0.16) (0.30)
0.07 0.08
(0.14) (0.16)
0.40 3.0
(0.80) (6.0)
£1°
1.2
(2.4)
1.0
(2.0)
0.70
(1.4)
0.50
(1.0)
0.35
(0.70)
0.30
(0.60)
2.0
(4.0)
aReference 5. NA = not available.
^MH =
CFB =
dEI =
multiple hearth.
fluidized bed.
electric infrared.
M y . \j
00
"75
M ' ' J
O
4-1
0
CO
^ 6.0
G
O
•H
CO , c
to 4.5
•H
&
0)
' W « f\
o 3.0
rH
O
u 1.5
c
o
o
3 0
_
Control 1*d-^^ l^
NV ^Xy
^V ^^^ 1
^^^^^^ 1
^*s"^ I
~ \f^^^^ i
— •" J
1 /
/
/
/
/
/\.
S ^S.
./ \— Uncontrolled
^^^^
^^—^^^^^^^^^
i i 1111111 i i 1111111 i it
0.1 1.0 1°
n ia
_
™
_
_
i i i 1 1
3
*•••»»
60
0.15 *
•»
M
O
4J
0.12 «
U-l
C
0.09 °
CO
co
•H
B
0.06 ^
0)
rH
0.03 S
c
o
CJ
0
100
Partlclt 4UMt«r
9/90
Figure 2.5-5. Cumulative particle size distribution and
size-specific emission factors for
multiple-hearth incinerators.
Solid Waste Disposal
2.5-11
-------
O.I
To io~
P«rtlclt dUiwttr (u«)
0.24
0.20
0.16
oo
x
60
1-1
o
0.12 .2
CO
CO
B
0.08 *
-a
CU
100
0.04 2
0
j-l
C
O
o
Figure 2.5-6. Cumulative particle size distribution and
size-specific emission factors for
fluidized-bed incinerators.
oo
ae
00
J«
. 5
v>
o
4*
u
« A
C
o
6
O
o
So
O.I
Uncontrolled
To
Pirtlelt dl«MUr
100
1.50
1.25
1.0
0.75
0.50
0.25
0
oo
s
oo
O
4-1
O
c
o
•H
CO
CO
•H
CU
13
CU
c
o
o
Figure 2.5-7. Cumulative particle size distribution
size-specific emission factors for
electric(infrared) incinerators.
and
2.5-12
EMISSION FACTORS
9/90
-------
References for Section 2.5
1. Second Review Of Standards Of Performance For Sewage Sludge Incinerators.
EPA-450/3-84-010, U. S. Environmental Protection Agency, Research Triangle
Park, NC, March 1984.
2. Process Design Manual For Sludge Treatment And Disposal. EPA-625/1-79-011,
U. S. Environmental Protection Agency, Cincinnati, OH, September 1979.
3. Control Techniques For Particulate Emissions From Stationary Sources - Volume 1.
EPA-450/3-81-005a, U. S. Environmental Protection Agency, Research Triangle Park,
NC, September 1982.
4. Emission Factor Documentation For AP-42 Section 2.5: Sewage Sludge Incineration.
EPA-450/4-90-017, U. S. Environmental Protection Agency, Research Triangle Park,
NC, August 1990.
9/90 Solid Waste Disposal 2.5-13
-------
4.2.2.13 Magnetic Tape Manufacturing Industry-*-""
Magnetic tape manufacturing is a subcategory of industrial paper
coating, which includes coating of foil and plastic film. In the
manufacturing process, a mixture of magnetic particles, resins and solvents is
coated on a thin plastic film or "web". Magnetic tape is used largely for
audio and video recording and computer information storage. Other uses
include magnetic cards, credit cards, bank transfer ribbons, instrumentation
tape, and dictation tape. The magnetic tape coating industry is included in
two Standard Industrial Classification codes, 3573 (Electronic Computing
Equipment) and 3679 (Electronic Components Not Elsewhere Classified).
-I r\
Process Description - The process of manufacturing magnetic tape
consists of:
1) mixing the coating ingredients (including solvents)
2) conditioning the web
3) applying the coating to the web
4) orienting the magnetic particles
5) drying the coating in a drying oven,
6) finishing the tape by calendering, rewinding, slitting, testing,
and packaging.
Figure 4.2.2.13-1 shows a typical magnetic tape coating operation,
indicating volatile organic compound (VOC) emission points. Typical plants
have from 5 to 12 horizontal or vertical solvent storage tanks, ranging in
capacity from 3,800 to 75,700 liters (1,000 to 20,000 gallons), that are
operated at or slightly above atmospheric pressure. Coating preparation
equipment includes the mills, mixers, polishing tanks, and holding tanks used
to prepare the magnetic coatings before application. Four types of coaters
are used in producing magnetic tapes: extrusion (slot die), gravure, knife,
and reverse roll (3- and 4-roll). The web may carry coating on one or both
sides. Some products receive a nonmagnetic coating on the back. After
coating, the web is guided through an orientation field, in which an
electromagnet or permanent magnet aligns the individual magnetic particles in
the intended direction. Webs from which flexible disks are to be produced do
not go through the orientation process. The coated web then passes through a
drying oven, where the solvents in the coating evaporate. Typically, air
flotation ovens are used, in which the web is supported by jets of drying air.
For safe operation, the concentration of solvent vapors is held between 10 and
40 percent of the lower explosive limit. The dry coated web may be passed
through several calendering tolls to compact the coating and to smooth the
surface finish. Nondestructive testing is performed on up to 100 percent of
the final product, depending on the level of precision required of the final
product. The web may then be slit into the desired tape widths. Flexible
disks are punched from the finished web with a die. The final product is then
packaged. Some plants ship the coated webs in bulk to other facilities for
slitting and packaging.
*
High performance tapes require very clean production conditions,
especially in the coating application and drying oven areas. Air supplied to
9/90 Evaporation Loss Sources 4.2.2.13-1
-------
10
Ni
LEGEND
A
4 VOC EMISSIONS
STORAGE
TANK
wn ROOM
COATING NIX
COMPONENTS
1
nix
*
SANDHILL
DISPERSING
HOLDING
TANK
COATING--TO
COATER HEAD
§
H
O
pa
in
COATING-FROM
HOLDING TANK
UNWIND
COATER HEAD
(REVERSE-ROLL TYPE)
D
ORIENTATION
(FERRITE MAGNETS
OR ELECTROMAGNETS)
DRYING OVEN
(AIR FLOTATION TYPE)
CIRCULAR
SLITTING BLADES
CALENDERING
(OPTIONAL)
REMIND
SLITTING
(OPTIONAL)
vo
vo
O
Figure 4.2.2.13-1. Schematic drawing of a magnetic tape coating plant.1
-------
these areas is conditioned to remove dust particles and to adjust the
temperature and humidity. In some cases, "clean room" conditions are
rigorously maintained.
Emissions And Controls^"** - The significant VOC emission sources in a
magnetic tape manufacturing plant include the coating preparation equipment,
the coating application and flashoff area, and the drying ovens. Emissions
from the solvent storage tanks and the cleanup area are generally only a
negligible percentage of total emissions.
In the mixing or coating preparation area, VOCs are emitted from the
individual pieces of equipment during the following operations: filling of
mixers and tanks; transfer of the coating; intermittent activities, such as
changing the filters in the holding tanks; and mixing (if equipment is not
equipped with tightly fitting covers). Factors affecting emissions in the
mixing areas include the capacity of the equipment, the number of pieces of
equipment, solvent vapor pressure, throughput, and the design and performance
of equipment covers. Emissions will be intermittent or continuous, depending
on whether the preparation method is batch or continuous.
Emissions from the coating application area result from the evaporation
of solvent during use of the coating application equipment and from the
exposed web as it travels from the coater to the drying oven (flashoff).
Factors affecting emissions are the solvent content of the coating, line width
and speed, coating thickness, volatility of the solvent(s), temperature,
distance between coater and oven, and air turbulence in the coating area.
Emissions from the drying oven are of the remaining solvent that is
driven off in the oven. Uncontrolled emissions at this point are determined
by the solvent content of the coating when it reaches the oven. Because the
oven evaporates all the remaining solvent from the coating, there are no
process VOC emissions after oven drying.
Solvent type and quantity are the common factors affecting emissions
from all operations in a magnetic tape coating facility. The rate of
evaporation or drying depends on solvent vapor pressure at a given temperature
and concentration. The most commonly used organic solvents are toluene,
methyl ethyl ketone, cyclohexanone, tetrahydrofuran, and methyl isobutyl
ketone. Solvents are selected for their cost, solvency, availability, desired
evaporation rate, ease of use after recovery, compatibility with solvent
recovery equipment, and toxicity.
Of the total uncontrolled VOC emissions from the mixing area and coating
operation (application/flashoff area and drying oven), approximately 10
percent is emitted from the mixing area, and 90 percent from the coating
operation. Within the coating operation, approximately 10 percent occurs in
the application/flashoff area, and 90 percent in the drying oven.
A control system for evaporative emissions consists of two components, a
capture device and a control device. The efficiency of the control system is
determined by the efficiencies of the two components.
9/90 Evaporation Loss Sources 4.2.2.13-3
-------
A capture device is used to contain emissions from a process operation
and direct them to a stack or to a control device. Room ventilation systems,
covers, and hoods are possible capture devices from coating preparation
equipment. Room ventilation systems, hoods, and partial and total enclosures
are typical capture devices used in the coating application area. A drying
oven can be considered a capture device, because it both contains and directs
VOC process emissions. The efficiency of a capture device or a combination of
capture devices is variable and depends on the quality of design and the
levels of operation and maintenance.
A control device is any equipment that has as its primary function the
reduction of emissions to the atmosphere. Control devices typically used in
this industry are carbon adsorbers, condensers and incinerators. Tightly
fitting covers on coating preparation equipment may be considered both capture
and control devices, because they can be used either to direct emissions to a
desired point outside the equipment or to prevent potential emissions from
escaping.
Carbon adsorption units use activated carbon to adsorb VOCs from a gas
stream, after which the VOCs are desorbed and recovered from the carbon. Two
types of carbon adsorbers are available, fixed bed and fluidized bed. Fixed
bed carbon adsorbers are designed with a steam-stripping technique to recover
the VOCs and to regenerate the activated carbon. The fluidized bed units used
in this industry are designed to use nitrogen for VOC vapor recovery and
carbon regeneration. Both types achieve typical VOC control efficiencies of
95 percent when properly designed, operated and maintained.
Condensers control VOC emissions by cooling the solvent-laden gas to the
dew point of the solvent(s) and then collecting the droplets. There are two
condenser designs commercially available, nitrogen (inert gas) atmosphere and
air atmosphere. These systems differ in the design and operation of the
drying oven (i. e., use of nitrogen or air in the oven) and in the method of
cooling the solvent-laden air (i. e., liquified nitrogen or refrigeration).
Both design types can achieve VOC control efficiencies of 95 percent.
Incinerators control VOC emissions by oxidation of the organic compounds
into carbon dioxide and water. Incinerators used to control VOC emissions may
be of thermal or catalytic design and may use primary or secondary heat
recovery to reduce fuel costs. Thermal incinerators operate at approximately
890°C (1600°F) to assure oxidation of the organic compounds. Catalytic
incinerators operate in the range of 400 to 540 C (750 to 1000 F) while
using a catalyst to achieve comparable oxidation of VOCs. Both design types
achieve a typical VOC control efficiency of 98 percent.
Tightly fitting covers control VOC emissions from coating preparation
equipment by reducing evaporative losses. The parameters affecting the
efficiency of these controls are solvent vapor pressure, cyclic temperature
change, tank size, and product throughput. A good system of tightly fitting
covers on coating preparation equipment reduces emissions by as much as 40
percent. Control efficiencies of 95 or 98 percent can be obtained by venting
the covered equipment to an adsorber, condenser or incinerator.
4.2.2.13-4 EMISSION FACTORS 9/90
-------
When the efficiencies of a capture device and control device are known,
the. efficiency of the control system can be computed by the following
equation:
capture control device control system
efficiency x efficiency = efficiency
The terms of this equation are fractional efficiencies rather than
percentages. For instance, a system of hoods delivering 60 percent of VOC
emissions to a 90 percent efficient carbon adsorber would have control system
efficiency of 54 percent (0.60 x 0.90 = 0.54). Table 4.2.2.13-1 summarizes
control system efficiencies, which may be used to estimate emissions in the
absence of measured data on equipment and coating operations.
TABLE 4.2.2.13-1. TYPICAL OF CONTROL EFFICIENCIES3
Control technology Control Efficiency
Coating Preparation Equipment
Uncontrolled 0
Tightly fitting covers 40
Sealed covers with
carbon adsorber/condenser 95
Coating Operation0
Local ventilation with
carbon adsorber/condenser 83
Partial enclosure with
carbon adsorber/condenser 87
Total enclosure with
carbon adsorber/condenser 93
Total enclosure with incinerator 95
aReference 1.
"To be applied to uncontrolled emissions from indicated process area, not from
entire plant.
clncludes coating application/flashoff area and drying oven.
Emission Estimation Techniques '^ - In this industry, realistic
emission estimates require solvent consumption data. The variations found in
coating formulations, line speeds' and products mean that no reliable
inferences can be made otherwise.
9/90 Evaporation Loss Sources 4.2.2.13-5
-------
In uncontrolled plants and in those where VOCs are recovered for reuse
or sale, plantwide emissions can be estimated by performing a liquid material
balance based on the assumption that all solvent purchased replaces that which
has been emitted. Any identifiable and quantifiable side streams should be
subtracted from this total. The liquid material balance may be performed
using the following general formula:
solvent quantifiable VOC
purchased " solvent output = emitted
The first term encompasses all solvent purchased, including thinners, cleaning
agents, and any solvent directly used in coating formulation. From this
total, any quantifiable solvent outputs are subtracted. Outputs may include
reclaimed solvent sold for use outside the plant or solvent contained in waste
streams. Reclaimed solvent that is reused at the plant is not subtracted.
The advantages of this method are that it is based on data that are
usually readily available, it reflects actual operations rather than
theoretical steady state production and control conditions, and it includes
emissions from all sources at the plant. Care should be taken not to apply
this method over too short a time span. Solvent purchase, production and
waste removal occur in cycles which may not coincide exactly.
Occasionally, a liquid material balance may be possible on a scale
smaller than the entire plant. Such an approach may be feasible for a single
coating line or group of lines, if served by a dedicated mixing area and a
dedicated control and recovery system. In this case, the computation begins
with total solvent metered to the mixing area, instead of with solvent
purchased. Reclaimed solvent is subtracted from this volume, whether or not
it is reused on the site. Of course, other solvent input and output streams
must be accounted, as previously indicated. The difference between total
solvent input and total solvent output is then taken to be the quantity of
VOCs emitted from the equipment in question.
Frequently, the configuration of meters, mixing areas, production
equipment, and controls will make the liquid material balance approach
impossible. In cases where control devices destroy potential emissions, or
where a liquid material balance is inappropriate for other reasons, plantwide
emissions can be estimated by summing the emissions calculated for specific
areas of the plant. Techniques for these calculations are presented below.
Estimating VOC emissions from a coating operation (application/flashoff
area and drying oven) starts with the assumption that the uncontrolled
emission level is equal to the quantity of solvent contained in the coating
applied. In other words, all the VOC in the coating evaporates by the end of
the drying process.
Two factors are necessary to calculate the quantity of solvent applied,
solvent content of the coating and the quantity of coating applied. Coating
solvent content can be either directly measured using EPA Reference Method 24
or estimated using coating formulation data usually available from the plant
owner/operator. The amount of coating applied may be directly metered. If it
is not, it must be determined from production data. These data should be
4.2.2.13-6 EMISSION FACTORS 9/90
-------
available from the plant owner/operator. Care should be taken in developing
these two factors to assure that they are in compatible units. In cases where
plant-specific data cannot be obtained, the information in Table 4.2.2.13-2
may be useful in approximating the quantity of solvent applied.
When an estimate of uncontrolled emissions is obtained, the controlled
emissions level is computed by applying a control system efficiency factor:
(uncontrolled VOC) x (1-control system efficiency) = (VOC emitted).
TABLE 4.2.2.13-2. SELECTED COATING MIX PROPERTIES3
Parameter
Unit
Range
Solids
VOC
Density of coating
Density of coating solids
Resins/binder
Magnetic particles
Density of magnetic material
Viscosity
Coating thickness
Wet
Dry
weight %
volume %
weight %
volume %
kg/1
lb/gal
kg/1
lb/gal
weight % of" solids
weight % of solids
kg/1
Pa-s
lbf -s/ft2
mil
/urn
mil
aReference 9. To be used when plant-specific data are unavailable
15-50
10-26
50-85
74-90
1.0-1.2
8-10
2.8-4.0
23-33
15-21
66-78
1.2-4.8
10-40
2.7-5.0
0.06-0.10
3.8-54
0.15-2.1
1.0-11
0.04-0.4
As previously explained, the control system efficiency is the product of the
efficiencies of the capture device and of the control device. If these values
are not known, typical efficiencies for some combinations of capture and
9/90
Evaporation Loss Sources
4.2.2.13-7
-------
control devices are presented in Table 4.2.2.13-1. It is important to note
that these control system efficiencies apply only to emissions that occur
within the areas serviced by the systems. Emissions from sources such as
process wastewater or discarded waste coatings may not be controlled at all.
In cases where emission estimates from the mixing area alone are
desired, a slightly different approach is necessary. Here, uncontrolled
emissions will consist of only that portion of total solvent that evaporates
during the mixing process. A liquid material balance across the mixing area
(i.e., solvent entering minus solvent content of coating applied) would
provide a good estimate. In the absence of any measured value, it may be
assumed, very approximately, that 10 percent of the total solvent entering the
mixing area is emitted during the mixing process. When an estimate of
uncontrolled mixing area emissions has been made, the controlled emission rate
can be calculated as discussed previously. Table 4.2.2.13-1 lists typical
overall control efficiencies for coating mix preparation equipment.
Solvent storage tanks of the size typically found in this industry are
regulated by only a few states and localities. Tank emissions are generally
small (130 kilograms per year or less). If an emissions estimate is desired,
it can be computed using the equations, tables and figures provided in Section
4.3.2.
References For Section 4.2.2.13
1. Magnetic Tape Manufacturing Industry - Background Information For
Proposed Standards. EPA-450/3-85-029a, U. S. Environmental Protection
Agency, Research Triangle Park, NC, December 1985.
2. 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.
3. C. Beall, "Distribution Of Emissions Between Coating Mix Preparation
Area And The Coating Line", Memorandum file, Midwest Research Institute,
Raleigh, NC, June 22, 1984.
4. C. Beall, "Distribution Of Emissions Between Coating Application/
Flashoff Area And Drying Oven", Memorandum to file, Midwest Research
Institute, Raleigh, NC, June 22, 1984.
5. Control Of Volatile Organic Emission From Existing Stationary Sources -
Volume I: Control Methods For Surface-coating Operations. EPA-450/2-76-
028, U. S. Environmental Protection Agency, Research Triangle Park, NC,
November 1976.
6. G. Crane, Carbon Adsorption For VOC Control. U. S. Environmental
Protection Agency, Research Triangle Park, NC, January 1982.
4.2.2.13-8 EMISSION FACTORS 9/90
-------
7. D. Mascone, "Thermal Incinerator Performance For NSPS", Memorandum,
Office Of Air Quality Planning And Standards, U. S. Environmental
Protection Agency, Research Triangle Park, NC, June 11, 1980.
8. D. Mascone, "Thermal Incinerator Performance For NSPS, Addendum",
Memorandum, Office Of Air Quality Planning And Standards, U. S.
Environmental Protection Agency, Research Triangle Park, NC, June 22,
1980.
9. C. Beall, "Summary Of Nonconfidential Information On U. S. Magnetic Tape
Coating Facilities", Memorandum, with attachment, to file, Midwest
Research Institute, Raleigh, NC, June 22, 1984.
9/90 Evaporation Loss Sources 4.2.2.13-9
-------
4.2.2.14 Surface Coating Of Plastic Partis For Business Machines
4.2.2.14.1 General1'2
Surface coating of plastic parts for business machines is defined as the
process of applying coatings to plastic business machines parts to improve the
appearance of the parts, to protect the parts from physical or chemical
stress, and/or to attenuate electromagnetic interference/radio frequency
interference (EMI/RFI) that would otherwise pass through plastic housings.
Plastic parts for business machines are synthetic polymers formed into panels,
housings, bases, covers, or other business machine components. The business
machines category includes items such as typewriters, electronic computing
devices, calculating and accounting machines, telephone and telegraph
equipment, photocopiers and miscellaneous office machines.
The process of applying an exterior coating to a plastic part can include
surface preparation, spray coating, and curing, with each step possibly being
repeated several times. Surface preparation may involve merely wiping off the
surface, or it could involve sanding and puttying to smooth the surface. The
plastic parts are placed on racks or trays, or are hung on racks or hooks from
an overhead conveyor track for transport among spray booths, flashoff areas
and ovens. Coatings are sprayed onto parts in partially enclosed booths. An
induced air flow is maintained through the booths to remove overspray and to
keep solvent concentrations in the room air at safe levels. Although low
temperature bake ovens (140° F or less) are often used to speed up the curing
process, coatings also may be partially or completely cured at room
temperature.
Dry filters or water curtains (in water wash spray booths) are used to
remove overspray particles from the booth exhaust. In waterwash spray booths,
most of the insoluble material is collected as sludge, but some of this
material is dispersed in the water along with the soluble overspray
components. Figure 4.2.2.14-1 depicts a typical dry filter spray booth, and
Figure 4.2.2.14-2 depicts a typical water wash spray booth.
Many surface coating plants have only one manually operated spray gun per
spray booth, and they interchange spray guns according to what type of
coating is to be applied to the plastic parts. However, some larger surface
coating plants operate several spray guns (manual or robotic) per spray booth,
because coating a large volume of similar parts on conveyor coating lines
makes production more efficient.
Spray coating systems commonly used in this industry fall into three
categories, three coat, two coat, and single coat. The three coat system is
the most common, applying a prime coat, a color or base coat, and a texture
coat. Typical dry film thickness for the three coat system ranges from 1 to
3 mils for the prime coat, 1 to 2 mils for the color coat, and 1 to 5 mils for
the texture coat. Figure 4.2.2.14-3 depicts a typical conveyorized coating
line using the three-coat system. The conveyor line consists of three
separate spray booths, each followed by a flashoff (or drying) area, all of
9/90 Evaporation Loss Sources 4.2.2.14-1
-------
Ni
Ni
SPRAY
BOOTH
EXHAUST
W
s
00
I— I
o
a
52
OPTIONAL
CONVEYORIZED
TRACK
MOTOR FOR
EXHAUST FAN
OVERSPRAY
FILTERED AIR
FILTER MATERIAL
OPENING FOR
MOVEMENT OF
OPTIONAL
CONVEYORIZED
TRACK
VO
o
Figure 4.2.2.14-1. Typical dry filter spray booth.3"4
-------
VO
O
O
l-t
O
O
CO
to
VI
§
SPRAY
BOOTH EXHAUST
MOTOR FOR
EXHAUST PAN
OVERSPRAY
FILTERED AIR
... WATER
WATER TREATMENT/
SLUDGE REMOVER UNIT
OPTIONAL \
CONVEYORIZED \
OPENING FOR
OPTIONAL
CONVEYORIZED TRACK
WATER BATH
TRACK
Figure 4.2.2.14-2. Typical waterwash spray booth.-
-------
which is followed by a curing oven. A two coat system applies a color or base
coat, then a texture coat. Typical dry film thickness for the two coat system
is 2 mils for the color (or base) coat and 2 to 5 mils for the texture coat.
The rarely used single coat system applies only a thin color coat, either to
protect the plastic substrate or to improve color matching between parts whose
color and texture are molded in. Less coating solids are applied with the
single coat system than with the other systems. The dry film thickness
applied for the single coat system depends on the function of the coating. If
protective properties are desired, the dry film thickness must be at least 1
mil (.001 inches). For purposes of color matching among parts having
molded-in color and texture, a dry film thickness of 0.5 mils or less is
needed to avoid masking the molded-in texture. The process of applying 0.5
mils of coating or less for color matching is commonly known as "fog coating",
"mist coating", or "uniforming".
The three basic spray methods used in this industry to apply
decorative/exterior coatings are air atomized spray, air-assisted airless
spray, and electrostatic air spray. Air atomized spray is the most widely
used coating technique for plastic business machine parts. Air-assisted
airless spray is growing in popularity but is still not frequently found.
Electrostatic air spray is rarely used, because plastic parts are not
conductive. It has been used to coat parts that have been either treated with
a conductive sensitizer or plated with a thin film of metal.
Air atomized spray coating uses compressed air, which may be heated and
filtered, to atomize the coating and to direct the spray. Air atomized spray
equipment is compatible with all coatings commonly found on plastic parts for
business machines.
Air-assisted airless spray is a variation of airless spray, a spray
technique used in other industries. In airless spray coating, the coating is
atomized without air by forcing the liquid coating through specially designed
nozzles, usually at pressures of 7 to 21 megapascals (MPa) (1,000 to 3,000
pounds per square inch). Air-assisted airless spray atomizes the coating by
the same mechanism as airless spray, but at lower fluid pressures (under 7
MPa). After atomizing, air is then used to atomize the coating further and to
help shape the spray pattern, reducing overspray to levels lower than those
achieved with airless atomization alone. Figure 4.2.2.14-4 depicts a typical
air-assisted airless spray gun. Air-assisted airless spray has been used to
apply prime and color coats but not texture coats, because the larger size of
the sprayed coating droplet (relative to that achieved by conventional air
atomized spray) makes it difficult to achieve the desired surface finish
quality for a texture coat. A touch-up coating step with air atomized
equipment is sometimes necessary to apply color to recessed and louvered areas
missed by air-assisted airless spray.
In electrostatic air spray, the coating is usually charged electrically,
and the parts being coated are grounded to create an electric potential
between the coating and the parts. The atomized coating is attracted to the
part by electrostatic force. Because plastic is an insulator, it is necessary
to provide a conductive surface that can bleed off the electrical charge to
maintain the ground potential of the part as the charged coating particles
accumulate on the surfaces. Electrostatic air spray has been demonstrated for
application of prime and color coats and has been used to apply texture coats,
4.2.2.14-4 EMISSION FACTORS 9/90
-------
v£>
CURING OVEN
O
i-l
O
3
o
10
CO
O
l-{
n
o>
to
LOADING/
UNLOADING
AREA
< 1
FLASH-OFF AREA
A
I
A
I
I
I
TEXTURE
BOOTH
VOC EMISSIONS
FLASH-OFF
AREA
A
1
1
1
PRIME
BOOTH
A
1
FLASH-OFF AREA
1
COLOR
BOOTH
N>
Figure 4.2.2.14-3. Typical conveyor line for three-coat system.
-------
Figure 4.2.2.14-4. Typical air assisted airless spray gun.5
but this technique does not function well with the large size particles
generated for the texture coat, and it offers no substantial improvement over
air atomized spray for texture coating. A touch-up coating step with air
atomized spray is sometimes necessary to apply color and texture to recessed
and louvered areas missed by electrostatic spray.
The coatings used for decorative/exterior coats are generally solvent-
based and waterborne coatings. Solvents used include toluene, methyl ethyl
ketone, methylene chloride, xylene, acetone and isopropanol. Typically,
organic solvent-based coatings used for decorative/exterior coats are two
types of two-component catalyzed urethanes. The solids contents of these
coatings are from 30 to 35 volume percent (low solids) and 40 to 54 volume
percent (medium solids) at the spray gun (i.e., at the point of application,
or as applied). Waterborne decorative/exterior coatings typically contain no
more than 37 volume percent solids at the gun. Other decorative/exterior
coatings being used by the industry include solvent-based high solids coatings
(i.e., equal to or greater than 60 volume percent solids) and one-component
low solids and medium solids coatings.
The application of an EMI/RFI shielding coat is done in a variety of
ways. About 45 percent of EMI/RFI shielding applied to plastic parts is done
by zinc-arc spraying, a process that does not emit volatile organic compounds
(VOC). About 45 percent is done using organic solvent-based and waterborne
metal-filled coatings, and the remaining EMI/RFI shielding is achieved by a
variety of techniques involving electroless plating, and vacuum metallizing or
sputtering (defined below), and use of conductive plastics, and metal inserts.
Zinc-arc spraying is a two-step process in which the plastic surface
(usually the interior of a housing) is first roughened by sanding or grit
blasting and then sprayed with molten zinc. Grit blasting and zinc-arc
spraying are performed in separate booths specifically equipped for those
activities. Both the surface preparation and the zinc-arc spraying steps
currently are performed manually, but robot systems have recently become
available. Zinc-arc spraying requires a spray booth, a special spray gun,
pressurized air and zinc wire. The zinc-arc spray gun mechanically feeds two
zinc wires into the tip of the spray gun, where they are melted by an electric
4.2.2.14-6 EMISSION FACTORS 9/90
-------
arc. A high pressure air nozzle blows the molten zinc particles onto the
surface of the plastic part. The coating thickness usually ranges from 1 to 4
mils, depending on product requirements.
Conductive coatings can be applied with most conventional spray equipment
used to apply exterior coatings. Conductive coatings are usually applied
manually with air spray guns, although air-assisted airless spray guns are
sometimes used. Electrostatic spray methods can not be used because of the
high conductivity of EMI/RFI shielding coatings.
Organic solvent-based conductive coatings contain particles of nickel,
silver, copper or graphite, in either an acrylic or an urethane resin.
Nickel-filled acrylic coatings are the most frequently used, because of their
shielding ability and their lower cost. Nickel-filled acrylics and urethanes
contain from 15 to 25 volume percent solids at the gun. Waterborne nickel-
filled acrylics with between 25 and 34 volume percent solids at the gun
(approximately 50 to 60 volume percent solids, minus water) are less
frequently used than, are organic-solvent-based conductive coatings.
The application of a conductive coating usually involves three steps:
surface preparation, coating application, and curing. Although the first step
can be eliminated if parts are kept free of mold-release agents and dirt, part
surfaces are usually cleaned by wiping with organic solvents or detergent
solutions and then roughened by light sanding. Coatings are usually applied
to the interior surface of plastic housings, at a dry film thickness of 1 to
3 mils. Most conductive coatings can be cured at room temperature, but some
must be baked in an oven.
Electroless plating is a dip process in which a film of metal is
deposited in aqueous solution onto all exposed surfaces of the part. In the
case of plastic business machine housings, both sides of a housing are
coated. No VOC emissions are associated with the plating process itself.
However, coatings applied before the plating step, so that only selected areas
of the parts are plated, may emit VOCs. Wastewater treatment may be necessary
to treat the spent plating chemicals.
Vacuum metallizing and sputtering are similar techniques in which a thin
film of metal (usually aluminum) is deposited from the vapor phase onto the
plastic part. Although no VOC emissions occur during the actual metallizing
process, prime coats often applied to ensure good adhesion and top coats to
protect the metal film may both emit VOCs.
Conductive plastics are thermoplastic resins that contain conductive
flakes or fibers of materials such as aluminum, steel, metallized glass or
carbon. Resin types currently available with conductive fillers include
acrylonitrile butadiene styrene, acrylonitrile butadiene styrene/polycarbonate
blends, polyphenylene oxide, nylon 6/6, polyvinyl chloride, and polybutyl
terephthalate. The conductivity, and therefore the EMI/RFI shielding
effectiveness, of these materials relies on contact or near contact between
the conductive particles within the resin matrix. Conductive plastic parts
usually are formed by straight injection molding. Structural foam injection
molding can reduce the EMI/RFI shield effectiveness of these materials because
air pockets in the foam separate the conductive particles.
9/90 Evaporation Loss Sources 4.2.2.14-7
-------
4.2.2.14.2 Emissions And Controls
The major pollutants from surface coating of plastic parts for business
machines are VOC emissions from evaporation of organic solvents in the
coatings used, and from reaction byproducts when the coatings cure. VOC
sources include spray booth(s), flashoff area(s), and oven(s) or drying
areas(s). The relative contribution of each to total VOC emissions from a
from plant to plant, but for an average coating operation, about 80 percent is
emitted from the spray booth(s), 10 percent from the flashoff area(s), and 10
percent from the oven(s) or drying area(s).
Factors affecting the quantity of VOC emitted are the VOC content of the
coatings applied, the solids content of coatings as applied, film build
(thickness of the applied coating), and the transfer efficiency (TE) of the
application equipment. To determine of VOC emissions when waterborne coatings
are used, it is necessary to know the amounts of VOC, water and solids in the
coatings.
0
The TE is the fraction of the solids sprayed that remains on a part. TE
varies with application technique and with type of coating applied.
Table 4.2.2.14-1 presents typical TE values for various application methods.
TABLE 4.2.2.14-1. TRANSFER EFFICIENCIES"
Application methods
Transfer
efficiency
Type of coating
Air atomized spray
Air-assisted airless spray
Electrostatic air spray
25
40
40
Prime, color, texture,
touchup and fog coats
Prime, color coats
Prime, color coats
"As noted in the promulgated standards, values are presented solely to
aid in determining compliance with the standards and may not reflect
actual TE at a given plant. For this reason, table should be used with
caution for estimating VOC emissions from any new facility. For a more
exact estimate of emissions, the actual TE from specific coating
operations at a given plant should be used.1
Volatile organic compound emissions can be reduced by using low
VOC-content coatings (i.e., high solids or waterborne coatings), using surface
finishing techniques that do not emit VOC, improved TE, and/or added controls.
Lower VOC content decorative/exterior coatings include high solids-content
(i.e., at least 60 volume percent solids at the spray gun) two-component
catalyzed urethane coatings and,waterborne coatings (i.e., 37 volume percent
solids and 12.6 volume percent VOC at the spray gun). Both of these types of
exterior/decorative coatings contain less VOC than conventional urethane
4.2.2.14-8
EMISSION FACTORS
9/90
-------
vo
o
TABLE 4.2.2.14-2. REPRESENTATIVE PARAMETERS FOR SURFACE COATING OPERATIONS TO APPLY
DECORATIVE/EXTERIOR COATINGS3
w
o
II
o
CO
tn
O
i-t
O
0>
(0
Operating Surface area
Plant schedule Number of spray booths coated/yr Coating option/
size (h/yr) Dry filter Water wash (m2 of plastic) control technique
Small 4,000 2 0 9,711 Baseline coating mix"
Low solids SB coating
Medium solids SB coating6
High solids SB coating*
WB coating
Medium 4,000 5* 0 77,743 Baseline coating mixb
Low solids SB coating
Medium solids SB coating6
High solids SB coating
WB coating11
Large 4,000 &l 3* 194,370 Baseline coating mixb
Low solids SB coating
Medium solids SB coating6
High solids SB coating*
WB coating*1
Coating
sprayed (£/yr)
16,077°
18,500C
11,840C
9,867C/
6,167?
16,000C
128,704C
148,100C
94,784C
78,987C/
49,3679
128,086C
321,760C
370,275°
236,976°
197,480C/
123, 425?
320,238°
i*Does not address EMI/RFI shielding coatings. SB = solventborne. WB = waterborne.
Assumes baseline decorative/exterior coating consumption consists of a mix of coatings as follows:
64.8% = Solvent base two-component catalyzed urethane containing 32 volume I solids at the gun.
23.5% = Solvent base two-component catalyzed urethane containing 50 volume % solids at the gun.
11.7% = Waterborne acrylic containing 37 volume % solids and 12.6 volume % organic solvent
at the gun.
°Assumes 25% transfer efficiency (TE) based on the use of air atomized spray equipment.
-------
CO
CO
o
H
CO
vo
vO
o
TABLE 4.2.2.14-2 (cont.)
Assumes use of a solvent base coating containing 32 volume I solids at the gun.
^Assumes use of a solvent base coating containing 50 volume % solids at the gun.
Assumes the use of a solvent base two-component catalyzed urethane coating containing 60 volume * solids at the gun.
•^Assumes 40* TE based on the use of air assisted airless spray equipment, as required by new source performance standards.
.Assumes the use of a waterborne coating containing 37 volume % solids and 12.6 volume % organic solvent at the gun.
^Assumes two spray booths are for batch surface coating operations and remaining three booths are on a conveyor line.
^Assumes two spray booths are for batch surface coating operations and remaining four Booths are on a conveyor line
Assumes that three spray booths are on a conveyor line.
-------
TABLE 4.2.2.14-3. REPRESENTATIVE PARAHETERS FOR SURFACE COATING OPERATIONS TO APPLY
VO
o
Operating
Plant schedule
size (h/yr)
Small 4,000
PJ
id
o
t-i
S Hediun 4,000
o
3
O
CO
en
O
H
0
S Large 4,000
NJ
Ni
EHI/RFI SHIELDING COATINGS3
Number of spray booths Surface area
Grit Zinc arc coated/yr Coating option/
blasting3 spray3 (m2 of plastic) control technique
0 0 4,921 LOW solids SB EHI/RFI
shielding coating0'
Higher solids SB EHI/RFI
shielding coating6'
WB EHI/RFI shielding
coating1'"
Zinc arc spray?"1
2 2 109,862 Low solids SB EHI/RFI
shielding coating0'"
Higher solids SB EHI/RFI
shielding coating6'
WB EHI/RFI shielding
coating1'"
Zinc arc spray?"1
4 4 239,239 Low solids SB EHI/RFI
shielding coating0'
Higher solids SB EHI/RFI
shielding coating6'"
WB EHI/RFI shielding
coating1'"
Zinc arc spray?"1
Coating sprayed
(p /yj"^
3,334
2,000
1,515
750
74,414
44,648
33,824
16,744
162,040
97,224
73,654
34,460
-------
m
s
M
CO
(/I
h-H
o
2!
n
H
TABLE 4.2.2.14-3 (cont.)
alncludes sprayed conductive coatings using the dry filter and water wash spray booths listed in Table 4.2.2.14-2. SB = solventborne. WB
waterborne.
Assumes 50* transfer efficiency (TE).
^Assumes use of a solvent base EMI/RFI shielding coating containing 15 volume % solids at the gun.
Applied at a 2 rail thickness (standard industry practice).
^Assumes use of a solvent base EMI/RFI shielding coating containing 25 volume I solids at the gun.
Assumes use of a waterborne EMI/RFI shielding coating containing 33 volume % solids and 18.8 volume * organic solvent at the gun.
•JAssunes use of zinc-arc spray shielding.
.Applied at a 3 mil thickness (standard industry practice).
on amount of zinc wire sprayed per year (kg/yr) and zinc density of 6.32 g/ml.
IO
O
-------
\O
O
TABLE 4.2.2.14-4. EMISSION FACTORS FOR VOC FROM SURFACE
COATING OPERATIONS TO APPLY DECORATIVE/EXTERIOR COATINGS3'5
T)
O
l-S
O
3
r
o
W
Cfl
O
1-1
o
(D
CO
Plant configuration
Volatile oroanics
J
and control technique
Small
Baseline coating mixc
Low solids SB coating
Medium solids SB coating6
High solids SB coating*
WB Coating?
Medium
Baseline coating mixc
Low solids SB coating
Medium solids SB coating6
High solids SB coating*
WB Coating?
Large
Baseline coating mixc
Low solids SB coatingd
Medium solids SB coating6
High solids SB coating*
WB Coating?
kg/m coated
0.84
1.14
0.54
0.36/0.22
0.18
0.84
1.14
0.54
0.36/0.22
0.18
0.84
1.14
0.54
0.36/0.22
0.18
kg/yr
8,122
11,096
5,221
3,481/2,176
1,778
64,986
88,825
41,800
27,867/17,417
14,234
162,463
222,076
104,506
69,671/43,544
35,589
kg/hr
2.0
2.8
1.3
0.87/0.54
0.44
16.2
22.2
10.4
7.0/4.4
3.6
40.6
55.5
26.1
17.4/10.9
8.9
Ni
N>
I
l->
u>
-------
Ni
M TABLE 4.2.2.14-4 (cent.)
i-1
•o
i
I? aAssumes values given in Table 4.2.2.14-2, using the following equation: E = LDV.
where:
E = VOC emission factors from surface coating operations (kg/yr)
L = Volume of coating sprayed (£)
D = Density of coating sprayed (kg/£)
V = Volatile content of coating, including dilution solvents
added at plant (weight fraction).
"Assumes all VOC present is emitted. Values have been rounded off. Does not address EMI/RFI shielding coatings. Assumes annual operating schedule
s of 4,000 hours. SB = solventborne. WB = waterborne.
oo ^Based on use of the baseline coating mix in Table 4.2.2.14-2.
M dBased on use of a solvent base coating containing 32 volume % solids at the gun.
§ %sed on use of a solvent base coating containing 50 volume % solids at the gun.
T) fBased on use of a solvent base coating containing 60 volume % solids at the gun.
o ^uased on use of a waterborne coating containing 37 volune % solids and 12.6 volume I organic solvent at the gun.
vO
o
-------
vO
O
TABLE 4.2.2.14-5. EMISSION FACTORS FOR VOC FROM SURFACE
COATING OPERATIONS TO APPLY EMI/RFI SHIELDING COATINGSa'b
•a
o
it
o
(0
W
en
o
fi
o
0>
Plant configuration
and control technique
kg/nr coated
Volatile organics
kg/yr kg/hr
Small
Low Solids SB EMI/RFI shielding coating0
Higher solids SB EMI/RFI shielding coating"
WB EMI/RFI shielding coating6
Zinc-arc spray
Medium
Low solids SB EMI/RFI shielding coating0
Higher solids SB EMI/RFI shielding coatingd
WB EMI/RFI shielding coating6
Zinc-arc spray*
Large
Low solids SB EMI/RFI shielding coating0
Higher solits SB EMI/RFI shielfing coating"
WB EMI/RFI shielding coating6
Zinc-arc spray
0.51
0.27
0.05
0
0.51
0.27
0.05
0
0.51
0.27
0.05
0
2,500
1,323
251
0
55,787
29,535
5,609
0
121,484
64,314
12,214
0
0.62
0.33
0.063
0
13.9
7.4
1.4
0
30.4
16.1
3.1
0
-------
!o TABLE 4.2.2.14-5 (cont.)
•P-
£ aAssumes values given in Table 4.2.2.14-3, using the following equation: E = LDV
where:
E = VOC emission factors from EMI/RFI shielding coating operations (kg/yr)
L = Volume of coating sprayed (£)
D = Density of coating sprayed (kg/£)
V = Volatile content of coating, including dilution solvents
added at plant (fraction by weight).
"Assunes all VOC present is emitted. Values have been rounded off. Does not address EMI/RFI shielding coatings. Assumes annual operating
§ schedule of 4,000 hours. SB = solventborne. WB = waterborne.
w ^Assumes use of a solvent base EMI/RFI shielding coating containing 15 volume % solids a the gun.
M Assumes use of a solvent base EMI/RFI shielding coating containing 25 volume % solids at the gun.
§ ^Assumes use of a waterborne EMI/RFI shielding coating containing 33 volume % solids and 18.8 volume % organic solvent at the gun.
*j Assumes use of a zinc-arc spray shielding.
H
00
iO
o
-------
coatings, which are typically 32 volume percent solids at the gun. Lower VOC
content EMI/RFI shielding coatings include organic solvent-based acrylic or
urethane conductive coatings containing at least 25 volume percent solids at
the spray gun and waterborne conductive coatings containing 30 to 34 volume
percent solids at the gun. Use of lower VOG content coatings reduces
emissions of VOCs both by reducing the volume of coating needed to cover the
part(s) and by reducing the amount of VOC in the coatings that are sprayed.
The major technique which provides an attractive exterior/decorative
finish on plastic parts for business machines without emitting VOCs is the use
of molded-in color and texture. VOC-free techniques for EMI/RFI shielding
include zinc-arc spraying, electroless plating, the use of conductive plastics
or metal inserts, and in some cases, vacuum metallizing and sputtering.
Transfer efficiency can be improved by using air-assisted airless or
electrostatic spray equipment, which are more efficient than the common
application technique (air atomized). More efficient equipment can reduce VOC
emissions by as much as 37 percent over conventional air atomized spray
equipment, through reducing the amount of coating that must be sprayed to
achieve a given film thickness.
Addon controls applied to VOC emissions in other surface coating
industries include thermal and catalytic incinerators, carbon adsorbers and
condensers. However, these control technologies have not been used in the
surface coating of plastic parts because the large volume of exhaust air and
the low concentrations of VOC in the exhaust reduce their efficiency.
The operating parameters in Tables 4.2.2.14-2 and 4.2.2.14-3 and the
emissions factors in Tables 4.2.2.14-4 and 4.2.2.14-5 are representative of
conditions at existing plants with similar operating characteristics. The
three general sizes of surface coating plants presented in these tables
(small, medium and large) are given to assist in making a general estimate of
VOC emissions. However, each plant has its own combination of coating
formulations, application equipment and operating parameters. Thus, it is
recommended that, whenever possible, plant-specific values be obtained for all
variables when calculating emission estimates.
A material balance may be used to provide a more accurate estimate of
VOC emissions from the surface coating of plastic parts for business machines.
An emissions estimate can be calculated using coating composition data (as
determined by EPA Reference Method 24) and data on coating and solvent
quantities used in a given time period by a surface coating operation. Using
this approach, emissions are calculated as follows:
n
I L,i DC, W01
where:
MT = total mass of VOC emitted (kg)
Lc = volume of each coating consumed, as sprayed (£)
Dc = density of each coating as sprayed (k/£)
9/90 Evaporation Loss Sources 4.2.2.14-17
-------
W0 = the proportion of VOC in each coating, as sprayed (including
dilution solvent added at plant) (weight fraction)
n = number of coatings applied .
References for Section 4.2.2.14
1. Surface Coating Of Plastic Parts For Business Machines - Background
Information for Proposed Standards. EPA-450/3-85-019a, U. S.
Environmental Protection Agency, Research Triangle Park, NC, December
1985.
2. Written communication from Midwest Research Institute, Raleigh, NC, to
David Salman, U. S. Environmental Protection Agency, Research Triangle
Park, NC, June 19, 1985.
3. Protectaire" Spray Booths, Protectaire Systems Company, Elgin, IL, 1982.
4. BinksR Spray Booths and Related Equipment, Catalog SB-7, Binks
Manufacturing Company, Franklin Park, IL, 1982.
5. Product Literature on Wagner8 Air Coat" Spray Gun, Wagner Spray
Technology, Minneapolis, MN, 1982.
4.2.2.14-18 EMISSION FACTORS 9/90
-------
5.19 SYNTHETIC FIBER MANUFACTURING
5.19.1 General
1-3
There are two types of synthetic fiber products, the semisynthetics, or
cellulosics, (viscose rayon and cellulose acetate) and the true synthetics, or
noncellulosics, (polyester, nylon, acrylic and modacrylic, and polyolefin).
These six fiber types compose over 99 percent of the total production of
manmade fibers in the U. S.
5.19.2 Process Description2"6
Semisynthetics are formed from natural polymeric materials such as
cellulose. True synthetics are products of the polymerization of smaller
chemical units into long chain molecular polymers. Fibers are formed by
forcing a viscous fluid or solution of the polymer through the small orifices
of a spinneret (see Figure 5.19-1) and immediately solidifying or
precipitating the resulting filaments. This prepared polymer may also be used
in the manufacture of other than fiber products, such as the enormous number
of extruded plastic and synthetic rubber products.
SPINNING SOLUTION
OR DOPE
FIBERS
Figure 5.19-1. Spinneret.
Synthetic fibers (both semisynthetic and true synthetic) are produced
typically by two easily distinguishable methods, melt spinning and solvent
spinning. Melt spinning processes use heat to melt the fiber polymer to a
viscosity suitable for extrusion through the spinneret. Solvent spinning
processes use large amounts of organic solvents, which usually are recovered
for economic reasons, to dissolve the fiber polymer into a fluid polymer
solution suitable for extrusion through a spinneret. The major solvent
spinning operations are dry spinning and wet spinning. A third method,
9/90
Chemical Process Industry
5.19-1
-------
-reaction spinning, is also used, but to a much lesser extent. Reaction
spinning processes involve the formation of filaments from prepolymers and
monomers that are further polymerized and cross linked after the filament is
formed.
Figure 5.19-2 is a general process diagram for synthetic fiber
production using the major types of fiber spinning procedures. The spinning
process used for a particular polymer is determined by the polymer's melting
point, melt stability and solubility in organic and/or inorganic (salt)
solvents. (The polymerization of the fiber polymer is typically carried out
at the same facility that produces the fiber.) Table 5.19-1 lists the
different types of spinning methods with the fiber types produced by each
method. After the fiber is spun, it may undergo one or more different
processing treatments to meet the required physical or handling properties.
Such processing treatments include drawing, lubrication, crimping, heat
setting, cutting, and twisting. The finished fiber product may be classified
as tow, staple, or continuous filament yarn.
TABLE 5.19-1. TYPES OF SPINNING METHODS AND
FIBER TYPES PRODUCED
Spinning method Fiber type
Melt spinning Polyester
Nylon 6
Nylon 66
Polyolefin
Solvent spinning
Dry solvent spinning Cellulose acetate
Cellulose triacetate
Acrylic
Modacrylic
Vinyon
Spandex
Wet solvent spinning Acrylic
Modacrylic
Reaction spinning Spandex
Rayon (viscose process)
Melt Spinning - Melt spinning uses heat to melt the polymer to a
viscosity suitable for extrusion. This type of spinning is used for polymers
that are not decomposed or degraded by the temperatures necessary for
extrusion. Polymer chips may be melted by a number of methods. The trend is
toward melting and immediate extrusion of the polymer chips in an electrically
heated screw extruder. Alternatively, the molten polymer is processed in an
inert gas atmosphere, usually nitrogen, and is metered through a precisely
machined gear pump to a filter assembly consisting of a series of metal gauges
interspersed in layers of graded sand. The molten polymer is extruded at high
5.19-2 EMISSION FACTORS 9/90
-------
VD
VD
o
n
(D
a
O
O
0>
(0
W
to
rt
i-i
(N
Ln
I
(D
3
3 *
S°
£
-------
pressure and constant rate through a spinneret into a relatively cooler air
stream which solidifies the filaments. Lubricants and finishing oils are
applied to the fibers in the spin cell. At the base of the spin cell, a
thread guide converges the individual filaments to produce a continuous
filament yarn, or a spun yarn, that typically is composed of between 15 and
100 filaments. Once formed, the filament yarn either is immediately wound
onto bobbins or is further treated for certain desired characteristics or end
use. Treatments include drawing, lubrication, crimping, heat setting,
cutting, and twisting.
Since melt spinning does not require the use of solvents, VOC emissions
are significantly lower than those from dry and wet solvent spinning
processes. Lubricants and oils are sometimes added during the spinning of the
fibers to provide certain propertj.es necessary for subsequent operations, such
as lubrication and static suppression. These lubricants and oils vaporize,
condense, and then coalesce as aerosols primarily from the spinning operation,
although certain post-spinning operations may also give rise to these aerosol
emissions.
Dry Solvent Spinning - The dry spinning process begins by dissolving the
polymer in an organic solvent. This solution is blended with additives and
is filtered to produce a viscous polymer solution, referred to as "dope", for
spinning. The polymer solution is then extruded through a spinneret as
filaments into a zone of heated gas or vapor. The solvent evaporates into
the gas stream and leaves solidified filaments, which are further treated
using one or more of the processes described in the general process
description section. (See Figure 5.19-3.) This type of spinning is used for
easily dissolved polymers such as cellulose acetate, acrylics and modacrylics.
POLYMER
^rjflTTj spmcnjL
SOLVENT-LADEN
STREAM TO
RECOVERY
PRODUCT
Figure 5.19-3. Dry spinning.
5.19-4
EMISSION FACTORS
9/90
-------
Dry spinning is the fiber formation process potentially emitting the
largest amounts of VOC per pound of fiber produced. Air pollutant emissions
include volatilized residual monomer, organic solvents, additives, and other
organic compounds used in fiber processing. Unrecovered solvent constitutes
the major substance. The largest amounts of unrecovered solvent are emitted
from the fiber spinning step and drying the fiber. Other emission sources
include dope preparation (dissolving the polymer, blending the spinning
solution, and filtering the dope), fiber processing (drawing, washing,
crimping) and solvent recovery.
Wet Solvent Spinning - Wet spinning also uses solvent to dissolve the
polymer to prepare the spinning dope. The process begins by dissolving polymer
chips in a suitable organic solvent, such as dimethylformamide (DMF),
dimethylacetamide (DMAc), or acetone, as in dry spinning; or in a weak
inorganic acid, such as zinc chloride or aqueous sodium thiocyanate. In wet
spinning, the spinning solution is extruded through spinnerets into a
precipitation bath that contains a coagulant (or precipant) such as aqueous
DMAc or water. Precipitation or coagulation occurs by diffusion of the
solvent out of the thread and by diffusion of the coagulant into the thread.
Wet spun filaments also undergo one or more of the additional treatment
processes described earlier, as depicted in Figure 5.19-4.
POLYMER
SOLVENT
DOPE
PREPARATION
VOC EMISSIONS
A
PRECIPITATION
BATH SOLUTION
UY
• UTb ~Mte>
LVENT/WATER T
MIXTURE) L
PRODUCT
MORE CONCENTRATED
SOLUTION OF
SOLVENT AND WATER
TO RECOVERY
SPINNERET
Figure 5.19-4. Wet spinning.
Air pollution emission points in the wet spinning organic solvent
process are similar to those of dry spinning. Wet spinning processes that use
solutions of acids or salts to dissolve the polymer chips emit no solvent VOC,
only unreacted monomer, and are, therefore, relatively clean from an air
pollution standpoint. For those that require solvent, emissions occur as
solvent evaporates from the spinning bath and from the fiber in post-spinning
operations.
9/90
Chemical Process Industry
5.19-5
-------
Reaction Spinning - As in the wet and dry spinning processes, the
reaction spinning process begins with the preparation of a viscous spinning
solution,which is prepared by dissolving a low molecular weight polymer, such
as polyester for the production of spandex fibers, in a suitable solvent and a
reactant, such as di-isocyanate. The spinning solution is then forced through
spinnerets into a solution containing a diamine, similarly to wet spinning, or
is combined with the third reactant and then dry spun. The primary
distinguishable characteristic of reaction spinning processes is that the
final cross-linking between the polymer molecule chains in the filament occurs
after the fibers have been spun. Post-spinning steps typically include drying
and lubrication. Emissions from the wet and dry reaction spinning processes
are similar to those of solvent wet and dry spinning, respectively.
5.19.3 Emissions And Controls
For each pound of fiber produced with the organic solvent spinning
processes, a pound of polymer is dissolved in about 3 pounds of solvent.
Because of the economic value of the large amounts of solvent used, capture
and recovery of these solvents are an integral portion of the solvent spinning
processes. At present, 94 to 98 percent of the solvents used in these fiber
formation processes is recovered. In both dry and wet spinning processes,
capture systems with subsequent solvent recovery are applied most frequently
to the fiber spinning operation alone, because the emission stream from the
spinning operation contains the highest concentration of solvent and, there-
fore, possesses the greatest potential for efficient and economic solvent
recovery. Recovery systems used include gas adsorption, gas absorption,
condensation, and distillation and are specific to a particular fiber type or
spinning method. For example, distillation is typical in wet spinning
processes to recover solvent from the spinning bath, drawing, and washing (see
Figure 5.19-8), while condensers or scrubbers are typical in dry spinning
processes for recovering solvent from the spin cell (see Figures 5.19-6 and
5.19-9). The recovery systems themselves are also a source of emissions from
the spinning processes.
The majority of VOC emissions from pre-spinning (dope preparation, for
example) and post-spinning (washing, drawing, crimping, etc.) operations
typically are not recovered for reuse. In many instances, emissions from
these operations are captured by hoods or complete enclosures to prevent
worker exposure to solvent vapors and unreacted monomer. Although already
captured, the quantities of solvent released from these operations are
typically much smaller than those released during the spinning operation. The
relatively high air flow rates required in order to reduce solvent and monomer
concentrations around the process line to acceptable health and safety limits
make recovery economically unattractive. Solvent recovery, therefore, is
usually not attempted.
Table 5.19-2 presents emission factors from production of the most
widely known semisynthetic and true synthetic fibers. These emission factors
address emissions only from the spinning and post-spinning operations and the
associated recovery or control systems. Emissions from the polymerization of
the fiber polymer and from the preparation of the fiber polymer for spinning
are not included in these emission factors. While significant emissions occur
in the polymerization and related processes, these emissions are discussed in
Sections 5.13, "Plastics", and 5.20, "Synthetic Rubber".
5.19-6 EMISSION FACTORS 9/90
-------
TABLE 5.19-2. EMISSION FACTORS FOR SYNTHETIC FIBER MANUFACTURING
EMISSION FACTOR RATING: C
Type of Fiber
Rayon, viscose process
Cellulose acetate, filter tow
Cellulose acetate and
triacetate , filament yarn
Polyester, melt spun
Staple
Yarnk
Acrylic, dry spun
Uncontrolled
Controlled
Modacrylic, dry spun
Acrylic and modacrylic, wet spun
Acrylic, inorganic wet spun
Homopolymer
Copolymer
Nylon 6, melt spun
Staple
Yarn
Nylon 66, melt spun
Uncontrolled
Controlled
Polyolefin, melt spun
Spandex, dry spun
Spandex, reaction spun
Vinyon, dry spun
Nonme thane
Volatile
Organics
0
112d
199d,e
0.6f '&
0.05f'S
40
32m
125S'h
6.75?
2.75S'r
3.93S
0.45s
2.13f 't
0.31f'v
56
4.23m
138X
150m
Particulate
c
c
c
25.2h'J .
0.036> J
c
c
c
c
c
c
O.OlS
c
0.5U
O.lu
O.OlS
c
c
c
References
7-8,10,35-36
11,37
11,38
41-42
21,43-44
45
19,46
47-48
25,49
26
5,25,28,49
32
50-51
52
aFactors are pounds of emissions per 1000 pounds of fiber spun, including
waste fiber.
^Uncontrolled carbon disculfide (CS2) emissions are 251 Ib CS2/1000 Ib fiber
spun; uncontrolled hydrogen sulfide emissions are 50.4 Ib I^S/IOOO Ib fiber
9/90
Chemical Process Industry
5.19-7
-------
TABLE 5.19-2 (CONT.).
spun. If recovery of €82 from the "hot dip" stage takes place, CS2 emissions
are reduced by about 16%.
°Particulate emissions from the spinning solution preparation area and later
stages through the finished product are essentially nil.
"After recovery from the spin cells and dryers. Use of more extensive
recovery systems can reduce emissions by 40% or more.
eUse of methyl chloride and methanol as the solvent, rather than acetone, in
production of triacetate can double emissions.
fEmitted in aerosol form.
^Uncontrolled.
_After control on extrusion parts cleaning operations.
^Mostly particulate,. with some aerosols.
^Factors for high intrinsic viscosity industrial and tire yarn production are
0.18 Ib VOC and 3.85 Ib particulate.
mAfter recovery from spin cells.
nAbout 18 Ib is from dope preparation, and about 107 Ib is from spinning/post-
spinning operations.
PAfter solvent recovery from the spinning, washing, and drawing stages. This
factor includes acrylonitrile emissions. An emission factor of 87 lb/1000 Ib
fiber has been reported.
^Average emission factor; range is from 13.9 to 27.7 Ib.
rAverage emision factor; range is from 2.04 to 16.4 Ib.
sAfter recovery of emissions from the spin cells. Without recovery, emission
factor would be 1.39 Ib.
^•Average of plants producing yarn from batch and continuous polymerization
processes. Range is from abut 0.5 to 4.9 Ib. Add 0.1 Ib to the average
factor for plants producing tow or staple. Continous polymerization
processes average emission rates approximately 170%. Batch polymerization
processes average emission rates approximately 80%.
uFor plants with spinning equipment cleaning operations.
vAfter control of spin cells in plants with batch and continuous
polymerization processes producing yarn. Range is from 0.1 to 0.6 Ib. Add
0.02 Ib to the average controlled factor for producing tow or staple. Double
the average controlled .emission factor for plants using continuous
polymerization only; subract 0.01 Ib for plants using batch plymerization
only.
wAfter control of spinning equipment cleaning operation.
xAfter recovery by carbon adsorption from spin cells and post-spinning
operations. Average collection efficiency 83%. Collection efficiency of
carbon adsorber decreases over 18 months from 95% to 63%.
5.19-8 EMISSION FACTORS 9/90
-------
Examination of VOC pollutant emissions from the synthetic fibers
industry has recently concentrated on those fiber production processes that
use an organic solvent to dissolve the polymer for extrusion or that use an
organic solvent in some other way during the filament forming step. Such
processes, while representing only about 20 percent of total industry
production, do generate about 94 percent of total industry VOC emissions.
Particulate emissions from fiber plants are relatively low, at least an order
of magnitude lower than the solvent VOC emissions.
5.19.4 Semi synthetics
Rayon Fiber Process Description^' '"•*• - In the United States, most rayon
is made by the viscose process. Rayon fibers are made using cellulose
(dissolved wood pulp), sodium hydroxide, carbon disulfide, and sulfuric acid.
As shown in Figure 5.19-5, the series of chemical reactions in the viscose
process used to make rayon consists of the following stages:
1. Wood cellulose and a concentrated solution of sodium hydroxide
react to form soda cellulose.
2. The soda cellulose reacts with carbon disulfide to form sodium
cellulose xanthate.
3. The sodium cellulose xanthate is dissolved in a dilute solution of
sodium hydroxide to give a viscose solution.
4. The solution is ripened or aged to complete the reaction.
5 . The viscose solution is extruded through spinnerets into dilute
sulfuric acid, which regenerates the cellulose in the form of
continuous filaments .
Emissions And Controls - Air pollutant emissions from viscose rayon
fiber production are mainly carbon disulfide (CS2), hydrogen sulfide (F^S),
and small amounts of particulate matter. Most C§2 and l^S emissions occur
during the spinning and post-spinning processing operations. Emission
controls are not used extensively in the rayon fiber industry. A counter-
current scrubber (condenser) is used in at least one instance to recover CS2
vapors from the sulfuric acid bath alone. The emissions from this operation
are high enough in concentration and low enough in volume to make such
recovery both technically and economically feasible. The scrubber recovers
nearly all of the CS2 and I^S that enters it, reducing overall CS2 and I^S
emissions from the process line by about 14 percent. While carbon adsorption
systems are capable of CS2 emission reductions of up to 95 percent, attempts
to use carbon adsorbers have had serious problems.
Cellulose Acetate And Triacetate Fiber Process Description^ »H-14 .
cellulose acetate and triacetate fibers are produced by dry spinning. These
fibers are used for either cigarette filter tow or filament yarn. Figure
5.19-6 shows the typical process for the production of cigarette filter tow.
Dried cellulose acetate polymer flakes are dissolved in a solvent, acetone
and/or a chlorinated hydrocarbon in a closed mixer. The spinning solution
(dope) is filtered, as it is with other fibers. The dope is forced through
spinnerets to form cellulose acetate filaments, from which the solvent rapidly
9/90 Chemical Process Industry 5.19-9
-------
Figure 5.19-5. Rayon viscose process.
evaporates as the filaments pass down a spin cell or column. After the
filaments emerge from the spin cell, there is a residual solvent content which
continues to evaporate more slowly until equilibrium is attained. The
filaments then undergo several post-spinning operations before they are cut
and baled.
In the production of filament yarn, the same basic process steps are
carried out as for filter tow, up through and including the actual spinning of
the fiber. Unlike filter tow filaments, however, filaments used for filament
yarn do not undergo the series of post-spinning operations shown in Figure
5.19-6, but rather are wound immediately onto bobbins as they emerge from the
spin cells. In some instances, a slight twist is given to the filaments to
meet product specifications. In another area, the wound filament yarn is
subsequently removed from the bobbins and wrapped on beams or cones (referred
to as "beaming") for shipment.
Emissions And Controls - Air pollutant emissions from cellulose acetate
fiber production include solvents, additives and other organic compounds used
in fiber processing. Acetone, methyl ethyl ketone and methanol are the only
solvents currently used in commercial production of cellulose acetate and
triacetate fibers.
In the production of all cellulose acetate fibers, i.e., tow, staple, or
filament yarn, solvent emissions occur during dissolving of the acetate
flakes, blending and filtering of the dope, spinning of the fiber, processing
of the fiber after spinning, and the solvent recovery process. The largest
emissions of solvent occur during spinning and processing of the fiber.
Filament yarns are typically not dried as thoroughly in the spinning cell as
are tow or staple yarns. Consequently, they contain larger amounts of residual
solvent, which evaporates into the spinning room air where the filaments are
5.19-10
EMISSION FACTORS
9/90
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VOC EMISSIONS
FIITMTION
ORWIIK
DOTING
CUTTING
Figure 5.19-6. Cellulose acetate and triacetate filter tow.
wound and into the room air where the wound yarn is subsequently transferred
to beams. This residual solvent continues to evaporate for several days,
until an equilibrium is attained. The largest emissions occur during the
spinning of the fiber and the evaporation of the residual solvent from the
wound and beamed filaments. Both processes also emit lubricants (various
vegetable and mineral oils) applied to the fiber after spinning and before
winding, particularly from the dryers in the cigarette filter tow process.
VOC control techniques are primarily carbon adsorbers and scrubbers.
They are used to control and recover solvent emissions from process gas
streams from the spin cells in both the production of cigarette filter tow and
filament yarn. Carbon adsorbers also are used to control and recover solvent
emissions from the dryers used in the production of cigarette filter tow. The
solvent recovery efficiencies of these recovery systems range-from 92 to 95
percent. Fugitive emissions from other post-spinning operations, even though
they are a major source, are generally not controlled. In at least one
instance however, an air management system is being used in which the air from
the dope preparation and beaming areas is combined at carefully controlled
rates with the spinning room air which is used to provide the quench air for
the spin cell. A fixed amount of spinning room air is then combined with the
process gas stream from the spin cell and this mix is vented to the recovery
system.
5.19.5 True Synthetic Fibers
Polyester Fiber Process Description5,11,15-17 . Polyethylene
terepthalate (PET) polymer is produced from ethylene glycol and either
dimethyl terepthalate (DMT) or terepthalic acid (TPA). Polyester filament
yarn and staple are manufactured either by direct melt spinning of molten PET
from the polymerization equipment or by spinning reheated polymer chips.
Polyester fiber spinning is done almost exclusively with extruders, which feed
9/90
Chemical Process Industry
5.19-11
-------
the molten polymer under pressure through the spinnerets. Filament
solidification is induced by blowing the filaments with cold air at the top of
the spin cell. The filaments are then led down the spin cell through a fiber
finishing application, from which they are gathered into tow, hauled off and
coiled into spinning cans. The post-spinning processes, steps 14 through 24
in Figure 5.19-7, usually take up more time and space and may be located far
from the spinning machines. Depending on the desired product, post-spinning
operations vary but may include lubrication, drawing, crimping, heat setting,
and stapling.
ETjfe.
11 L_*
i°?°J I-=Y— •* E "i •
6 7
i ± : : s
V8 12
- ^
__— — V 14
liijir7]
8 Spinneret
7 Corm
mtlonal haul-off
w 8 Blowing air
>r 9 Spinning shaft, solidification
•uder • 10 Finish application
Irect spinning, spinning manifold 1 1 Tow
Itton 12 H«ul-
nfuntt
13 Fibre can
TH*
14
15
18
17
18
19
20
21
Can creel
Finish
Drawing
Heating zone
(setting)
Crimping
Tow
Stapling (setting)
JLtt
«. 18 ^%,22
— LJ— L\W^Jtsi23
Ne5^CJ24
22 Flocks
23 Bale press
24 Carton filling
Figure 5.19-7. Polyester production.
Emissions And Controls - Air pollutant emissions from polyester fiber
production include polymer dust from drying operations, volatilized residual
monomer, fiber lubricants (in the form of fume or oil smoke), and the burned
polymer and combustion products from cleaning the spinning equipment.
Relative to the solvent spinning processes, the melt spinning of polyester
fibers does not generate significant amounts of volatilized monomer or
polymer, so emission control measures typically are not used in the spinning
area. Finish oils that are applied in polyester fiber spinning operations are
usually recovered and recirculated. When applied, finish oils are vaporized
in the spin cell to some extent and, in some instances, are vented to either
demisters, which remove some of the oils, or catalytic incinerators, which
oxidize significant quantities of volatile hydrocarbons. Small amounts of
finish oils are vaporized in the post-spinning process. Vapors from hot draw
operations are typically controlled by such devices as electrostatic
precipitators. Emissions from most other steps are not controlled.
Acrylic And Modacrylic Fiber Process Description '°> - Acrylic and
modacrylic fibers are based on acrylonitrile monomer, which is derived from
propylene and ammonia. Acrylics are defined as those fibers that are composed
of at least 85 percent acrylonitrile. Modacrylics are defined as those fibers
that are composed of between 35 and 85 percent acrylonitrile. The remaining
composition of the fiber typically includes at least one of the following -
methyl methacrylate, methyl acrylate, vinyl acetate, vinyl chloride, or
vinylidene chloride. Polyacrylonitrile fiber polymers are produced by the
5.19-12
EMISSION FACTORS
9/90
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industry using two methods, suspension polymerization and solution
polymerization. Either batch or continuous reaction modes may be employed.
As shown in Figures 5.19-8 and 5.19-9, the polymer is dissolved in a
suitable solvent, such as dimethylformamide or dimethylacetamide. Additives
and delusterants are added, and the solution is usually filtered in plate and
frame presses. The solution is then pumped through a manifold to the
spinnerets (usually a bank of 30 to 50 per machine). At this point in the
process, either wet or dry spinning may be used to form the acrylic fibers.
The spinnerets are in a spinning bath for wet spun fiber, or at the top of an
enclosed column for dry spinning. The wet spun filaments are pulled from the
bath on takeup wheels, then washed to remove more solvent. After washing, the
filaments are gathered into a tow band, stretched to improve strength, dried,
crimped, heat set, and then cut into staple. The dry spun filaments are
gathered into a tow band, stretched, dried, crimped, and cut into staple.
Emissions And Controls - Air pollutant emissions from the production of
acrylic and modacrylic fibers include emissions or acrylonitrile (volatilized
residual monomer), solvents, additives, and other organics used in fiber
processing. As shown in Figures 5.19-8 and 5.19-9, both the wet and the dry
spinning processes have many emission points. The major emission areas for
the wet spin fiber process are the spinning and washing steps. The major
emission areas from dry spinning of acrylic and modacrylic fibers are the
spinning and post-spinning areas, up through and including drying. Solvent
recovery in dry-spinning of modacrylic fibers is also a major emission point.
The most cost-effective method for reducing solvent VOC emissions from
both wet and dry spinning processes is a solvent recovery system. In wet
spinning processes, distillation is used to recover and recycle solvent from
the solvent/water stream that circulates through the spinning, washing, and
drawing operations. In dry spinning processes, control techniques include
scrubbers, condensers, and carbon adsorption. Scrubbers and condensers are
used to recover solvent emissions from the spinning cells and the dryers.
Carbon adsorption is used to recover solvent emissions from storage tank vents
and from mixing and filtering operations. Distillation columns are also used
in dry spinning processes to recover solvent from the condenser, scrubber, and
wash water (from the washing operation).
Nylon Fiber 6 and 66 Process Description->»1'» 24-27 . Nylon g polymer is
produced from caprolactam. Caprolactam is derived most commonly from
cyclohexanone, which in turn comes from either phenol or cyclohexane. About
70 percent of all nylon 6 polymer is produced by continuous polymerization.
Nylon 66 polymer is made from adipic acid and hexamethylene diamine, which
react to form hexamethylene diamonium adipate (AH salt). The salt is then
washed in a methyl alcohol bath. Polymerization then takes place under heat
and pressure in a batch process. The fiber spinning and processing procedures
are the same as described earlier in the description of melt spinning.
Emissions And Controls - The major air pollutant emissions from
production of nylon 6 fibers are volatilized monomer (caprolactam) and oil
vapors or mists. Caprolactam emissions may occur at the spinning step,
because the polymerization reaction is reversible and exothermic, and the heat
of extrusion causes the polymer to revert partially to the monomer form. A
monomer recovery system is used on caprolactam volatilized at the spinneret
9/90 Chemical Process Industry 5.19-13
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IWSNIK ORMIIK I FHISH MY I IB C8IW1PC SE1IIN6 CUTIIIB Ml I KG
nut
an
VOC EMISSIONS
wux ur
sunn
Figure 5.19-8. Acrylic fiber wet spinning.
RECOVERED SOLVENT
i VOC EMISSIONS
oo
PIOHING
BOX
Figure 5.19-9. Acrylic fiber dry spinning.
5.19-14
EMISSION FACTORS
9/90
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roi.no
CHIPS
spinner
Figure 5.19-10. Nylon production.
during nylon 6 fiber formation. Monomer recovery systems are not used in nylon
66 (polyhexamethylene adipamide) spinning operations, since nylon 66 does not
contain a significant amount of residual monomer. Emissions, though small,
are in some instances controlled by catalytic incinerators. The finish oils,
plasticizers and lubricants applied to both nylon 6 and 66 fibers during the
spinning process are vaporized during post-spinning processes and, in some
instances, such as the hot drawing of nylon 6, are vented to fabric filters,
scrubbers and/or electrostatic precipitators.
Polyolefin Fiber Process Description^'5>28-30 _ p0lyolefin fibers are
molecularly oriented extrusions of highly crystalline olefinic polymers,
predominantly polypropylene. Melt spinning of polypropylene is the method of
choice because the high degree of polymerization makes wet spinning or
dissolving of the polymer difficult. The fiber spinning and processing
procedures are generally the same as described earlier for melt spinning.
Polypropylene is also manufactured by the split film process, in which it is
extruded as a film and then stretched and split into flat filaments, or narrow
tapes, that are twisted or wound into a fiber. Some fibers are manufactured as
a combination of nylon and polyolefin polymers, being melted together in a
ratio of about 20 percent nylon 6 and 80 percent polyolefin such as
polypropylene, and being spun from this melt. Polypropylene is processed more
like nylon 6 than nylon 66, because of the lower melting point 203°C (397°F)
for nylon 6 versus 263°C (505°F) for nylon 66.
Emissions And Controls - Limited information is available on emissions
from the actual spinning or processing of polyolefin fibers. The available
data quantify and describe the emissions from the extruder/pelletizer stage,
the last stage of polymer manufacture, and from just before the melting of the
polymer for spinning. VOC content of the dried polymer after extruding and
9/90
Chemical Process Industry
5.19-15
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pelletizing was found to be as much as 0.5 weight percent. Assuming the
content is as high as 0.5 percent and that all this VOC is lost in the
extrusion and processing of the fiber (melting, spinning, drawing, winding,
etc.), there would be 5 pounds of VOC emissions per 1,000 pounds of polyolefin
fiber-. The VOCs in the dried polymer are hexane, propane and methanol, and
the approximate proportions are 1.6 pounds of hexane, 1.6 pounds of propane
and 1.8 pounds of methanol.
^2T
®
•
AJMALIIC OVU
P
VOC EMISSIONS
Figure 5.19-11. Polyolefin fiber production
During processing, lubricant and finish oils are added to the fiber, and
some of these additives are driven off in the form of aerosols during
processing. No specific information has been obtained to describe the oil
aerosol emissions for polyolefin processing, but certain assumptions may be
.made to provide reasonably accurate values. Because polyolefins are melt spun
similarly to other melt spun fibers (nylon 6, nylon 66, polyester, etc.), a
fiber similar to the polyolefins would exhibit similar emissions. Processing
temperatures are similar for polyolefins and nylon 6. Thus, aerosol emission
values for nylon 6 can be assumed valid for polyolefins.
c 01 o o
Spandex Fiber Manufacturing Process Description3' -> - Spandex is a
generic name for a polyurethane fiber in which the fiber-forming substance is
a long chain of synthetic polymer comprising of at least 85 percent of a
segmented polyurethane. In between the urethane groups, there are long chains
which may be polyglycols, polyesters or polyamides. Being spun from a
polyurethane (a rubber-like material), spandex fibers are elastomeric, that
is, they stretch. Spandex fibers are used in such stretch fabrics as belts,
foundation garments, surgical stockings, and stocking tops.
Spandex is produced by two different processes in the United States.
One process is similar in some respects to that used for acetate textile yarn,
in that the fiber is dry spun, immediately wound onto takeup bobbins, and then
twisted or processed in other ways. This process is referred to as dry
spinning. The other process, which uses reaction spinning, is substantially
different from any other fiber forming process used by domestic synthetic
fiber producers.
5.19-16
EMISSION FACTORS
9/90
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Spandex Dry Spun Process Description - This manufacturing process, which
is illustrated in Figure 5.19-12, is characterized by use of solution
polymerization and dry spinning with an organic solvent. Tetrahydrofuran is
the principal raw material. The compound's molecular ring structure is
opened, and the resulting straight chain compound is polymerized to give a low
molecular weight polymer. This polymer is then treated with an excess of a
di-isocyanate. The reactant, with any unreacted di-isocyanate, is next reacted
with some diamine, with monoamine added as a stabilizer. This final
polymerization stage is carried out in dimethylformamide solution, and then
the spandex is dry spun from this solution. Immediately after spinning,
spandex yarn is wound onto a bobbin as continuous filament yarn. This yarn is
later transferred to large spools for shipment or for further processing in
another part of the plant.
OISTILUTIM
VOC EMISSIONS
POlrHER FIBER
OUT
FINISH
APPIICATION
Figure 5.19-12. Spandex dry spinning.
Emissions And Controls - The major emissions from the spandex dry
spinning process are volatilized solvent losses, which occur at a number of
points of production. Solvent emissions occur during filtering of the spin
dope, spinning of the fiber, treatment of the fiber after spinning, and the
solvent recovery process. The emission points from this process are also
shown in Figure 5.19-12.
Total emissions from spandex fiber dry spinning are considerably lower
than from other dry spinning processes. It appears that the single most
influencing factor that accounts for the lower emissions is that, because of
nature of the polymeric material and/or spinning conditions, the amount of
residual solvent in the fiber as it leaves the spin cell is considerably lower
than other dry spun fibers. This situation may be because of the lower
9/90
Chemical Process Industry
5.19-17
-------
solvent/polymer ratio that is used in spandex dry spinning. Less solvent is
•used for each unit of fiber produced, relative to other fibers. A
condensation system is used to recover solvent emissions from the spin cell
exhaust gas. Recovery of solvent emissions from this process is as high as 99
percent. Since the residual solvent in the fiber leaving the spin cell is much
lower than for other fiber types, the potential for economic capture and
recovery is also much lower. Therefore, these post-spinning emissions, which
are small, are npt controlled.
Spandex Reaction Spun Process Description - In the reaction spun
process, a polyol (typically, polyester) is reacted with an excess of
di-isocynate to form the urethane prepolymer, which is pumped through
spinnerets at a constant rate into a bath of dilute solution of
ethylenediamine in toluene. The ethylenediamine reacts with isocyanate end
groups on the resin to form long chain cross-linked polyurethane elastomeric
fiber. The final cross linking reaction takes place after the fiber has been
spun. The fiber is transported from the bath to an oven, where solvent is
evaporated. After drying, the fiber is lubricated and is wound on tubes for
shipment.
Recovered
/Condenser j «
Room Air
Prepolymer
Filament
Winding
Conveyor
Drying
Oven
t
! VOC
i EMISSIONS
Figure 5.19-13. Spandex reaction spinning.
Emissions And Controls - Essentially all air that enters the spinning
room is drawn into the hooding that surrounds the process equipment and then
leads to a carbon adsorption system. The oven is also vented to the carbon
adsorber. The gas streams from the spinning room and oven are combined and
cooled in a heat exchanger before they enter the activated carbon bed.
Vinyon Fiber Process Description^'^ - Vinyon is a copolymer of vinyl
chloride (88 percent) and vinyl acetate (12 percent). The polymer is
dissolved in a ketone (acetone'or methyl ethyl ketone) to make a 23 weight
percent spinning solution. After filtering, the solution is extruded as
filaments into warm air to evaporate the solvent and to allow its recovery and
reuse. The spinning process is similar to that of cellulose acetate. After
5.19-18
EMISSION FACTORS
9/90
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spinning, the filaments are stretched to achieve molecular orientation to
impart strength.
Emissions And Controls - Emissions occur at steps similar to those of
cellulose acetate, at dope preparation and spinning, and as fugitive
emissions, from the spun fiber during processes such as winding and
stretching. The major source of VOC is the spinning step, where the warm air
stream evaporates the solvent. This air/solvent stream is sent to either a
scrubber or carbon adsorber for solvent recovery. Emissions may also occur at
the exhausts from these control device.
Other Fibers - There are synthetic fibers manufactured on a small volume
scale relative to the commodity fibers. Because of the wide variety of these
fiber manufacturing processes, specific products and processes are not
discussed. Table 5.19-3 lists some of these fibers and the respective
producers.
TABLE 5.19-3. OTHER SYNTHETIC FIBERS AND THEIR MAKERS
Nomex (aramid)
Kevlar (aramid)
FBI (polybenzimidazole)
Kynol (novoloid)
Teflon
DuPont
DuPont
Celanese
Carborundum
DuPont
Crimping:
Coagulant:
Continuous
filament
yarn:
Cutting:
Delusterant:
GLOSSARY
A process in which waves and angles are set into fibers,
such as acrylic fiber filaments, to help simulate properties
of natural fibers.
A substance, either a salt or an acid, used to precipitate
polymer solids out of emulsions or latexes.
Very long fibers that have been converged to form a
multifiber yarn, typically consisting of 15 to 100 filaments.
Refers to the conversion of tow to staple fiber.
Fiber finishing additives (typically clays or barium sulfate)
used to dull the surfaces of the fibers.
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Chemical Process Industry
5.19-19
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Dope:
Drawing:
Filament:
The polymer, either in molten form or dissolved in solvent,
that is spun into fiber.
The stretching of the filaments in order to increase the
fiber's strength; also makes the fiber more supple and
unshrinkable (that is, the stretch is irreversible). The
degree of stretching varies with the yarn being spun.
The solidified polymer that has emerged from a single hole or
orifice in a spinneret.
Filament yarn: (See continuous filament yarn)
Heat setting:
Lubrication:
Spinneret:
Spun yarn:
Staple:
Tow:
Twisting:
The dimensional stabilization of the fibers with heat so
that the fibers are completely undisturbed by subsequent
treatments such as washing or dry cleaning at a lower
temperature. To illustrate, heat setting allows a pleat to be
retained in the fabric, while helping prevent undesirable
creases later in the life of the fabric.
The application of oils or similar substances to the
fibers in order, for example, to facilitate subsequent
handling of the fibers and to provide static suppression.
A spinneret is used in the production of all man-made fiber
whereby liquid is forced through holes. Filaments emerging
from the holes are hardened and solidified. The process of
extrusion and hardening is called spinning.
Yarn made from staple fibers that- have been twisted or spun
together into a continuous strand.
Lengths of fiber made by cutting man-made fiber tow into
short (1- to 6-inch) and usually uniform lengths, which
are subsequently twisted into spun yarn.
A collection of many (often thousands) parallel, continuous
filaments, without twist, which are grouped together in
a rope-like form having a diameter of about one-quarter
inch.
Giving the filaments in a yarn a very slight twist that
prevents the fibers from sliding over each other when pulled,
thus increasing the strength of the yarn.
References for Section 5.19
1.
2.
Man-made Fiber Producer's Base Book. Textile Economics Bureau
Incorporated, New York, NY, 1977.
"Fibers - 540.000", Chemical Economics Handbook. Menlo Park, CA, March
1978.
5.19-20
EMISSION FACTORS
9/90
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3. Industrial Process Profiles For Environmental Use - Chapter 11 - The
Synthetic Fiber Industry. EPA Contract No. 68-02-1310, Aeronautical
Research Associates of Princeton, Princeton, NJ, November 1976.
4. R. N. Shreve, Chemical Process Industries. McGraw-Hill Book Company, New
York, NY, 1967.
5. R. W. Moncrief, Man-made Fibers. Newes-Butterworth, London, 1975.
6. Guide To Man-made Fibers. Man-made Fiber Producers Association, Inc.
Washington, DC, 1977.
7. "Trip Report/Plant Visit To American Enka Company, Lowland, Tennessee",
Pacific Environmental Services, Inc., Durham, NC, January 22, 1980.
8. "Report Of The Initial Plant Visit To Avtex Fibers, Inc., Rayon Fiber
Division, Front Royal, VA", Pacific Environmental Services, Inc.,
Durham, NC, January 15, 1980.
9. "Fluidized Recovery System Nabs Carbon Disulfide", Chemical Engineering.
70181:92-94, April 15, 1963.
10. Standards Of Performance For Synthetic Fibers NSPS, Docket No. A-80-7,
II-B-3, "Viscose Rayon Fiber Production - Phase I Investigation", U. S.
Environmental Protection Agency, Washington, DC, February 25, 1980.
11. "Report Of The Initial Plant Visit To Tennessee Eastman Company
Synthetic Fibers Manufacturing", Kingsport, TN, Pacific Environmental
Services, Inc., Durham, NC, December 13, 1979.
12. "Report Of The Phase II Plant Visit To Celanese's Celriver Acetate Plant
In Rock Hill, SC", Pacific Environmental Services, Inc., Durham, NC, May
28, 1980.
13. "Report Of The Phase II Plant Visit To Celanese's Celco Acetate Fiber
Plant In Narrows, VA", Pacific Environmental Services, Inc., Durham, NC,
August 11, 1980.
14. Standards Of Performance For Synthetic Fibers NSPS, Docket No. A-80-7,
II-I-43, U. S. Environmental Protection Agency, Washington, DC, December
1979.
15. E. Welfers, "Process And Machine Technology.Of Man-made Fibre
Production", International Textile Bulletin. World Spinning Edition,
Schlieren/Zurich, Switzerland, February 1978.
16. Written communication from R. B. Hayden, E. I. duPont de Nemours and
Co., Wilmington, DE, to E. L. Bechstein, Pullman, Inc., Houston, TX,
November 8, 1978.
17. Written communication from E. L. Bechstein, Pullman, Inc., Houston, TX,
to R. M. Glowers, U. S. Environmental Protection Agency, Research
Triangle Park, NC, November 17, 1978 .
9/90 Chemical Process Industry 5.19-21
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18.'- "Report Of The Plant Visit To Badische Corporation's Synthetic Fibers
Plant In Williamsburg, VA", Pacific Environmental Services, Inc.,
Durham, NC, November 28, 1979.
1.9. "Report Of The Initial Plant Visit To Monsanto Company's Plant In
Decatur, AL", Pacific Environmental Services, Inc., Durham, NC,
April 1, 1980.
20. "Report Of The Initial Plant Visit To American Cyanamid Company",
Pacific Environmental Services, Inc., Durham, NC, April 11, 1980.
21. Written communication from G. T. Esry, E. I. duPont de Nemours and Co.,
Wilmington, DE, to D. R. Goodwin, U. S. Environmental Protection Agency,
Research Triangle Park, NC, July 7, 1978.
22. "Report Of The Initial Visit To duPont's Acrylic Fiber Plant In
Waynesboro, VA", Pacific Environmental Services, Inc., Durham, NC,
May 1, 1980.
23. "Report Of The Phase II Plant Visit To duPont's Acrylic Fiber May Plant
In Camden, SC", Pacific Environmental Services, Inc., Durham, NC,
August 8, 1980.
24. C. N. Click and D. K. Webber, Polymer Industry Ranking By VOC Emission
Reduction That Would Occur From New Source Performance Standards. EPA
Contract No. 68-02-2619, Pullman, Inc., Houston, TX, August 30, 1979.
25. Written communication from E. L. Bechstein, Pullman, Inc., Houston, TX,
to R. M. Glowers, U. S. Environmental Protection Agency, Research
Triangle Park, NC, November 28, 1978.
26. Written communication from R. B. Hayden, E. I. duPont de Nemours and
Co., Wilmington, DE, to W. Talbert, Pullman, Inc., Houston, TX, October
17, 1978.
27. "Report Of The Initial Plant Visit To Allied Chemical's Synthetic Fibers
Division, Chesterfield, VA, Pacific Environmental Services, Inc.,
Durham, NC, November 27, 1979.
28. Background Information Document -- Polymers And Resins Industry.
EPA-450/3-83-019a, U. S. Environmental Protection Agency, Research
Triangle Park, NC, January 1984.
29. H. P. Frank, Polypropylene. Gordon and Breach Science Publishers, New
York, NY, 1968.
30. A. V. Galanti and C. L. Mantell, Polypropylene - Fibers and Films.
Plenum Press, New York, NY, 1965.
31. D. W. Grumpier, "Trip Report.- Plant Visit To Globe Manufacturing
Company", D. Grumpier, U. S. Environmental Protection Agency, Research
Triangle Park, NC, September 16 and 17, 1981.
5.19-22 EMISSION FACTORS 9/90
-------
32. "Standards Of Performance For Synthetic Fibers NSPS, Docket No. A-80-7,
II-I-115, Lycra Reamout Plan," U. S. Environmental Protection Agency,
Washington, DC, May 10, 1979.
33. "Standards Of Performance For Synthetic Fibers NSPS, Docket No. A-80-7,
II-I-95," U. S. Environmental Protection Agency, Washington, DC, March
2, 1982.
34. Written communication from W. K. Mohney, Avtex Fibers, Inc., Meadville,
PA, to R. Manley, Pacific Environmental Services, Durham, NC,
April 14, 1981.
35. Personal communication from J. H. Cosgrove, Avtex Fibers, Inc., Front
Royal, VA, to R. Manley, Pacific Environmental Services, Inc., Durham,
NC, November 29, 1982.
36. Written communication from T. C. Benning, Jr., American Enka Co.,
Lowland, TN, to R. A. Zerbonia, Pacific Environmental Services, Inc.,
Durham, NC, February 12, 1980.
37. Written communication from R. 0. Goetz, Virginia State Air Pollution
Control Board, Richmond, VA, to Director, Region II, Virginia State Air
Pollution Control Board, Richmond, VA, November 22, 1974.
38. Written communication from H. S. Hall, Avtex Fibers, Inc., Valley Forge,
PA, to J. R. Farmer, U. S. Environmental Protection Agency, Research
Triangle Park, NC, December 12, 1980.
39. Written communication from J. C. Pullen, Celanese Fibers Co., Charlotte,
NC, to R. A. Zerbonia, Pacific Environmental Services, Inc., Durham, NC,
July 3, 1980.
40. Written communication from J. C. Pullen, Celanese Fibers Co., Charlotte,
NC, to National Air Pollution Control Techniques Advisory Committee,
U. S. Environmental Protection Agency, Research Triangle Park, NC,
September 8, 1981.
41. "Report Of The Initial Plant Visit To Tennessee Eastman Company
Synthetic Fibers Manufacturing, Kingsport, TN", Pacific Environmental
Services, Inc., Durham, NC, December 13, 1979.
42. Written communication from J. C. Edwards, Tennessee Eastman Co.,
Kingsport, TN, to R. Zerbonia, Pacific Environmental Services, Inc.,
Durham, NC, April 28, 1980.
43. Written communication from C. R. Earnhart, E.I. duPont de Nemours and
Co., Camden, SC, to D. W. Grumpier, U. S. Environmental Protection
Agency, Research Triangle Park, NC, November 5, 1981.
44. C. N. Click and D. K. Weber, Emission Process And Control Technology
Study Of The ABS/SAN. Acrylic Fiber. And NBR Industries. EPA Contract
No. 68-02-2619, Pullman, Inc., Houston, TX, April 20, 1979.
9/90 Chemical Process Industry 5.19-23
-------
45. Written communication from D. 0. Moore, Jr., Pullman, Inc., Houston, TX,
to D. C. Mascone, U. S. Environmental Protection Agency, Research
Triangle Park, NC, April 18, 1979.
46. Written communication from W. M. Talbert, Pullman, Inc., Houston, TX, to
R.'J. Kucera, Monsanto Textiles Co., Decatur, AL, July 17, 1978.
47. Written communication from M. 0. Johnson, Badische Corporation,
Williamsburg, VA, to D. R. Patrick, U. S. Environmental Protection
Agency, Research Triangle Park, NC, June 1, 1979.
48. Written communication from J. S. Lick, Badische Corporation,
Williamsburg, VA, to D. R. Goodwin, U. S. Environmental Protection
Agency, Research Triangle Park, NC, May 14, 1980.
49. P. T. Wallace, "Nylon Fibers", Chemical Economics Handbook. Stanford
Research Institute, Menlo Park, CA, December 1977.
50. Written communication from R. Legendre, Globe Manufacturing Co., Fall
River, MA, to Central Docket Section, U. S. Environmental Protection
Agency, Washington, DC, August 26, 1981.
51. Written communication from R. Legendre, Globe Manufacturing Co., Fall
River, MA, to J. Farmer, U. S. Environmental Protection Agency, Research
Triangle Park, NC, June 26, 1980.
52. Written communication from R. H. Hughes, Avtex Fibers Co., Valley Forge,
PA, to R. Manley, Pacific Environmental Services, Inc., Durham, NC,
February 28, 1983.
53. "Report Of The Phase II Plant Visit, duPont's Acrylic Fiber May Plant In
Camden, SC", Pacific Environmental Services, Inc., Durham, NC,
April 29, 1980.
5.19-24 EMISSION FACTORS . 9/90
-------
Particulate emissions from sinter machines range from 5 to 20 percent of
the concentrated ore feed. In product weight, typical emissions are estimated
at 106.5 kilograms per megagram (213 pounds per ton) of lead produced. This
value and other particulate and 862 factors appear in Table 7.6-1.
Typical material balances from domestic lead smelters indicate that about
15 percent of the sulfur in ore concentrate fed to the sinter machine is
eliminated in the blast furnace. However, only half of this amount, about 7
percent of the total sulfur in the ore is emitted as S02.
The remainder is captured by the slag. The concentration of this S02
stream can vary from 1.4 to 7.2 grams per cubic meter (500 to 2500 parts per
million) by volume, depending on the amount of dilution air injected to
oxidize the carbon monoxide and to cool the stream before baghouse particulate
removal.
Particulate emissions from blast furnaces contain many kinds of material,
including a range of lead oxides, quartz, limestone, iron pyrites, iron-lime-
silicate slag, arsenic and other metallic compounds associated with lead ores.
These particles readily agglomerate and are primarily submicron in size,
difficult to wet, and cohesive. They will bridge and arch in hoppers. On
average, this dust loading is quite substantial, as is shown in Table 7.6-1.
Minor quantities of particulate are generated by ore crushing and
materials handling operations, and these emission factors are also presented
in Table 7.6-1.
TABLE 7.6-1. UNCONTROLLED EMISSION FACTORS FOR PRIMARY LEAD SMELTINGa
EMISSION FACTOR RATING: B
Total
Process
Ore crushing*3
Sintering (updraft)0
Blast furnaced
Parti
kg/Mg
1.0
106.5
180.5
culate
Ib/ton
2.0
213.0
361.0
Sulfur
kg/Mg
-
275.0
22.5
dioxide
Ib/ton
-
550.0
45.0
Lead
kg/Mg Ib/ton
0.15 0.3
87 174
(4.2-170) (8.4-340)
29 59
(8.7-50) (17.5-100)
Dross reverberatory
furnace
Materials
handl ing
10.
2.
0
5
20
5
.0
.0
Neg
Neg
(1
2
.4
3-3.5)
4.8
(2.6-7.0
aOre crushing factors expressed as kg/Mg (Ib/ton) of crushed ore. All other
factors are kg/Mg (Ib/ton) of lead product. Dash = no data. Neg =
negligible.
^References 2,13.
References 1, 4-6, 11, 14-17, 21-22.
References 1-2, 7, 12, 14, 16-17, 19.
References 2, 11-12, 14, 18, 20.
Reference 2.
9/90 Metallurgical Industry 7.6-5
-------
'.Table 7.6-2 and Figure 7.6-2 present size specific emission factors for
the controlled emissions from a primary lead blast furnace. No other size
distribution data can be located for point sources within a primary lead pro-
cessing plant. Lacking definitive data, size distributions for uncontrolled
assuming that the uncontrolled size distributions for the sinter machine and
blast furnace are the same as for fugitive emissions from these sources.
Tables 7.6-3 through 7.6-7 and Figures 7.6-3 through 7.6-7 present size
specific emission factors for the fugitive emissions generated at a primary lead
processing plant. The size distribution of fugitive emissions at a primary lead
processing plant is fairly uniform, with approximately 79 percent of these
emissions at less than 2.5 micrometers. Fugitive emissions less than 0.625
micrometers in size make up approximately half of all fugitive emissions, except
from the sinter machine, where they constitute about 73 percent.
Emission factors for total fugitive particulate from primary lead smelting
processes are presented in Table 7.6-8. The factors are based on a combination
of engineering estimates, test data from plants currently operating, and test
data from plants no longer operating. The values should be used with caution,
because of the reported difficulty in accurately measuring the source emission
rates.
Emission controls on lead smelter operations are for particulate and
sulfur dioxide. The most commonly employed high efficiency particulate control
devices are fabric filters and electrostatic preclpitators (ESP), which often
follow centrifugal collectors and tubular coolers (pseudogravity collectors).
Three of the six lead smelters presently operating in the United States use
single absorption sulfuric acid plants to control SC>2 emissions from sinter
machines and, occasionally, from blast furnaces. Single stage plants can
attain sulfur oxide levels of 5.7 grams per cubic meter (2000 parts per mill-
ion), and dual stage plants can attain levels of 1.6 grams per cubic meter (550
parts per million). Typical efficiencies of dual stage sulfuric acid plants in
removing sulfur oxides can exceed 99 percent. Other technically feasible S02
control methods are elemental sulfur recovery plants and dimethylaniline (DMA)
and ammonia absorption processes. These methods and their representative
control efficiencies are given in Table 7.6-9.
7.6-6 EMISSION FACTORS 10/86
-------
References For Section 7.10
1. Summary Of Factors Affecting Compliance By Ferrous Foundriesr
Text. EPA-340/1-80-020, U. S. Environmental Protection Agency,
Washington, DC, January 1981.
2. Air Pollution Aspects Of The Iron Foundry Industry. APTD-0806, U. S.
Environmental Protection Agency, Research Triangle Park, NC, February
1971.
3. Systems Analysis Of Emissions And Emission Control In The Iron Foundry
Industry. Volume II: Exhibits. APTD-0645, U. S. Environmental
Protection Agency, Research Triangle Park, NC, February 1971.
4. 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.
5. R. W. Hein, et al.. Principles Of Metal Casting. McGraw-Hill, New York,
1967.
6. P. Fennelly and P. Spawn, Air Pollution 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.
7. R. D. Chmielewski and S. Calvert, Flux Force/Condensation Scrubbing For
Collecting Fine Particulate From Iron Melting Cupola. EPA-600/7-81-148,
U. S. Environmental Protection Agency, Research Triangle Park, NC,
September 1981.
8. W. F. Hammond and S. M. Weiss, "Air Contaminant Emissions From
Metallurgical Operations In Los Angeles County", Presented at the Air
Pollution Control Institute, Los Angeles, CA, July 1964.
9. Particulate Emission Test Report On A Gray Iron Cupola At Cherryville
Foundry Works. Cherryville. NC. State Department Of Environmental Health
And Natural Resources, Raleigh, NC, December 18, 1975.
10. J. W. Davis and A. B. Draper, Statistical Analysis Of The Operating
Parameters Which Affect Cupola Emissions. DOE Contract No. EY-76-5-02-
2840.*000, Center For Air Environment Studies, Pennsylvania State
University, University Park, PA, December 1977.
11. Air Pollution Engineering Manual. Second Edition, AP-40, U. S.
Environmental Protection Agency, Research Triangle Park, NC, May 1973.
Out of Print.
12. Written communication from Dean Packard, Department Of Natural
Resources, Madison, WI, to Douglas Seeley, Alliance Technology, Bedford,
MA, April 15, 1982.
9/90 Metallurgical Industry 7.10-19
-------
13. Particulate Emissions Testing At Opelika Foundry. Birmingham. AL. Air
Pollution Control Commission, Montgomery, AL, November 1977 - January
1978.
14. Written communication from Minnesota Pollution Control Agency, St. Paul,
MM, to Mike Jasinski, Alliance Technology, Bedford, MA, July 12, 1982.
15. Stack Test Report. Dunkirk Radiator Corporation Cupola Scrubber. State
Department Of Environmental Conservation, Region IX, Albany, NY,
November 1975.
16. Particulate Emission Test Report For A Scrubber Stack For A Gray Iron
Cupola At Dewey Brothers. Goldsboro. NC. State Department Of
Environmental Health And Natural Resources, Raleigh, NC, April 7, 1978.
17. Stack Test Report. Worthington Corp. Cupola. State Department Of
Environmental Conservation, Region IX, Albany, NY, November 4-5, 1976.
18. Stack Test Report. Dresser Clark Cupola Wet Scrubber. Orlean. NY. State
Department Of -Environmental Conservation, Albany, NY, July 14 & 18,
1977.
19. Stack Test Report. Chevrolet Tonawanda Metal Casting. Plant Cupola 43
And Cupola #4. Tonawanda. NY. State Department Of Environmental
Conservation, Albany, NY, August 1977.
20. Stack Analysis For Particulate Emission. Atlantic States Cast Iron
Foundry/Scrubber. State Department Of Environmental Protection, Trenton,
NJ, September 1980.
21. S. Calvert, et al.r Fine Particle Scrubber Performance. EPA-650/2-74-
093, U. S. Environmental Protection Agency, Cincinnati, OH, October
1974.
22. S. Calvert, e£. al.. National Dust Collector Model 850 Variable Rod
Module Venturi Scrubber Evaluation. EPA-600/2-76-282, U. S.
Environmental Protection Agency, Cincinnati, OH, December 1976.
23. Source Test. Electric Arc Furnace At Paxton-Mitchell Foundry. Omaha. NB.
Midwest Research Institute, Kansas City, MO, October 1974.
24. Source Test. John Deere Tractor Works. East Moline. IL. Gray Iron
Electric Arc Furnace. Walden Research, Wilmington, MA, July 1974.
25. S. Gronberg, Characterization Of Inhalable Particulate Matter Emissions
From An Iron Foundry. Lynchburg Foundry. Archer Creek Plant. EPA-600/X-
85-328, U. S. Environmental Protection Agency, Cincinnati, OH, August
1984.
26. Particulate Emissions Measurements From The Rotoclone And General
Casting Shakeout Operations Of United States Pipe & Foundry. Inc.
Anniston. AL. Black, Crow and Eidsness, Montgomery, AL, November 1973,
7.10-20 EMISSION FACTORS 9/90
-------
27. Report Of Source Emissions Testing At Newbury Manufacturing. Talladega.
AL. State Air Pollution Control Commission, Montgomery, AL, May 15-16,
1979.
28. Particulate Emission Test Report For A Gray Iron Cupola At Hardy And
Newson. La Grange. NC. State Department Of Environmental Health And
Natural Resources, Raleigh, NC, August 2-3, 1977.
29. H. R. Crabaugh, et al,. "Dust And Fumes From Gray Iron Cupolas: How Are
They Controlled In Los Angeles County?", Air Repair. 4(3):125-130,
November 1954.
30. J. M. Kane, "Equipment For Cupola Control", American Foundryman's
Society Transactions. 64:525-531, 1956.
31. Control Techniques For Lead Air Emissions. 2 Volumes, EPA-450/2-77-012,
U. S. Environmental Protection Agency, Research Triangle Park, NC,
December 1977.
32. 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.
33. Emission Test No. EMB-71-CI-27, Office Of Air Quality Planning And
Standards, U. S. Environmental Protection Agency, Research Triangle
Park, NC, February 1972.
34. Emission Test No. EMB-71-CI-30, Office Of Air Quality Planning And
Standards, U. S. Environmental Protection Agency, Research Triangle
Park, NC, March 1972.
35. 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.
36. John Jeffery, et al.. Gray Iron Foundry Industry Particulate Emissions:
Source Category Report. EPA-600/7-86-054, U. S. Environmental Protection
Agency, Cincinnati, OH, December 1986.
9/90 Metallurgical Industry 7.10-21
-------
TABLE 10.1-1. EMISSION FACTORS FOR KRAFT PULPING9
EMISSION FACTOR RATING: A
Source
Digester relief and blow tank
Brown stock washer
Multiple effect evaporator
Recovery boiler and direct
evaporator
Noncontact recovery boiler
without direct contact
evaporator
Smelt dissolving tank
Lime kiln
Turpentine condenser
Miscellaneous11
Type of control
Untreated1*
Untreated1"
Untreatedb
Untreated4
Venturl
scrubber^
ESP
Auxiliary
scrubber
Untreated
ESP
Untreated
Mesh pad
Scrubber
Untreated
Scrubber or ESP
Untreated
Untreated
Participate
kg/Mg
_
-
90
24
1
1.5-7.58
115
1
3.5
0.5
0.1
28
0.25
-
-
Ib/ton
—
-
180
48
2
3-158
230
2
7
1
0.2
56
0.5
- '
-
Sulfur
dioxide (S02)
kg/Mg
_
-
3.5
3.5
3.5
-
-
0.1
0.1
-
0.15
-
-
-
Ib/ton
_
_
-
7
7
7
-
-
0.2
0.2
-
0.3
-
-
-
Carbon
monoxide (CO)
kg/Mg
.
-
-
5.5
5.5
5.5
5.5
5.5
_
_
-
0.05
0.05
-
-
Ib/ton
_
-
-
11
11
11
11
11
_
-
-
0.1
0.1
-
-
Hydrogen
sulflde (S")
kg/Mg
0.02
0.01
0.55
6e
6e
6«
6e
0.05h
0.05h
O.lJ
O.lJ
O.lJ
0.25m
0.25m
0.005
-
Ib/ton
0.03
0.02
1.1
12«
12«
12*
12e
O.lh
O.lh
0.2J
0.2.1
0.2J
0.5"
0.5°
.01
-
RSH, RSR.
RSSR (S")
kg/Mg
0.6
0.2C
0.05
1.5e
1.5«
1.56
1.5e
-
-
o.isJ
0.15J
0.15J
0.1°
0.1°
0.25
0.25
Ib/ton
1.2
0.4C
0.1
3e
3e
3e
3e
-
—
0.3J
0.3J
0.3J
0.2"
0.2"
0.5
0.5
o
o
I-S
O
n
rt
en
I
en
rt
t-1
o
aReferences 8-10. Factors expressed In unit weight of air dried unbleached pulp (ADP). RSH " Methyl oercaptan. RSR =
Dimethyl sulflde. RSSR » Dimethyl dlsulfide. ESP - Electrostatic preclpltator. Dash - No data.
blf noncondenslble gases from these sources are vented to lime kiln, recovery furnace or equivalent, the reduced sulfur
compounds are destroyed. .'
cApply with system using condensate as washing medium. When using fresh water, emissions are 0.05 (0.1).
dApply when cyclonic scrubber or cascade evaporator is used for direct contact evaporation, with no further controls.
eUsually reduced by SOX with black liquor oxidation and can be cut 95 - 99Z when oxidation is complete and recovery
furnace is operated optimally.
*Apply when venturi scrubber is used for direct contact evaporation, with no further controls.
gUse 7.5 (15) when auxiliary scrubber follows venturi scrubber, and 1.5 (3) when it follows ESP.
"Apply when recovery furnace is operated optimally to control total reduced sulfur (TRS) compounds.
JUsually reduced to 0.01 g/kg (0.02 Ib/ton) ADP when water low in sulfldes is used in smelt dissolving tank and
associated scrubber. /
"Usually reduced to 0.015 g/kg (0.03 Ib/ton) ADP with efficient mud washing, optimal kiln operation and added caustic
In scrubbing water. With only efficient mud washing and optimal process control, TRS compounds reduced to 0.04 g/kg
(0.08 Ib/ton) ADP.
"Includes knotter vents, brownstock seal tanks, etc. When black liquor oxidation is Included, emissions are 0.3 (0.6).
-------
TABLE 10.1-2. CUMULATIVE PARTICLE SIZE DISTRIBUTION AND SIZE SPECIFIC
EMISSION FACTORS FOR A RECOVERY BOILER WITH A DIRECT
CONTACT EVAPORATOR AND AN ESPa
EMISSION FACTOR RATING: C
Particle size
(urn)
15
10
6
2.5
1.25
1.00
0.625
Total
Cumulative mass % <^
stated size
Uncontrolled
95.0
93.5
92.2
83.5
56.5
45.3
26.5
100
Cont rol 1 ed
_
-
68.2
53.8
40.5
34.2
22.2
100
Cumulative emission factor
(kg/Mg of air dried pulp)
Uncontrolled
86
84
83
75
51
41
24
90
Controlled
mm
-
0.7
0.5
0.4
0.3
0.2
1.0
aReference 7. Dash = no data
100
90 -
80 -
o_ 70
g^ 60
ij 5°
•a *
V u_
^ o 40
85 30
G
^3
20
10
0.1
Uncontrolled
Controlled
1.0
9.9
D.8
0.7
0.6
0.5
0.4
0.3
0.2
0.1
' I I I I III
§1
"if
is.
1.0 10
Particle diameter (ym)
100
Figure 10.1-2. Cumulative particle size distribution and
specific emission factors for recovery boiler
with direct contact evaporator and ESP.
size
10.1-6
EMISSION FACTORS
10/86
-------
In discussing prescribed burning, the combustion process is divided into
preheating, flaming, glowing and smoldering phases. The different phases of
combustion greatly affect the amount of emissions produced. 5-7 fhe preheating
phase seldom releases significant quantities of material to the atmosphere.
Glowing combustion is usually associated with burning of large concentrations
of woody fuels such as logging residue piles. The smoldering combustion phase
is a very inefficient and incomplete combustion process that emits pollutants
at a much higher ratio to the quantity of fuel consumed than does the flaming
combustion of similar materials.
The amount of fuel consumed depends on the moisture content of the
For most fuel types, consumption during the smoldering phase is much greatest
when the fuel is driest. When. lower layers of the fuel are moist, the fire
usually is extinguished rapidly.^
The major pollutants from wildland burning are particulate, carbon monoxide
and volatile organics. Nitrogen oxides are emitted at rates of from 1 to A
grams per kilogram burned, depending on combustion temperatures. Emissions of
sulfur oxides are negligible. *1~12
Particulate emissions depend on the mix of combustion phase, the rate of
energy release, anxi the type of fuel consumed. All of these elements must be
considered in selecting the appropriate emission factor for a given fire and
fuel situation. In some cases, models developed by the U. S. Forest Service
have been used to predict particulate emission factors and source strength.^
These models address fire behavior, fuel chemistry, and ignition technique, and
they predict the mix of combustion products. There is insufficient knowledge
at this time to describe the effect of fuel chemistry on emissions.
Table 11.1-3 presents emission factors from various pollutants, by fire
and fuel configuration. Table 11.1-4 gives emission factors for prescribed
burning, by geographical area within the United States. Estimates of the
percent of total fuel consumed by region were compiled by polling experts
from the Forest Service. The emission factors are averages and can vary by
as much as 50 percent with fuel and fire conditions. To use these factors,
multiply the mass of fuel consumed per hectare by the emission factor for the
appropriate fuel type. The mass of fuel consumed by a fire is defined as the
available fuel. Local forestry officials often compile information on fuel
consumption for prescribed fires and have techniques for estimating fuel
consumption under local conditions. The Southern Forestry Smoke Management
Guidebook ^ and the Prescribed Fire Smoke Management Guide^-* should be consulted
when using these emission factors.
The regional emission factors in Table 11.1-4 should be used only for
general planning purposes. Regional averages are based on estimates of the
acreage and vegetation type burned and may not reflect prescribed burning
activities in a given state. Also, the regions identified are broadly defined,
and the mix of vegetation and acres burned within a given state may vary
considerably from the regional averages provided. Table 11.1-4 should not be
used to develop emission inventories and control strategies.
To develop state emission inventories, the user is strongly urged to con-
tact that state's federal land management agencies and state forestry agencies
that conduct prescribed burning to obtain, the best information on such activities.
9/88
Miscellaneous Sources 11.1-7
-------
TABLE 11.1-3. EMISSION FACTORS FOR PRESCRIBED BURNING*
00
Fire/fuel
configuration
Phase
Pollutant fo/kol
Particulate
PM2.5 PM10 Total
Carbon
monoxide
Volatile orqanics
Methane
Nomnethane
Fuel
mix
Emission
Factor
Rating
H
O
yo
to
VO
O
Broadcast logging
slash
Hardwoodb
Conifer
Short needlec
Long needle
Logging slash debris
Dozer piled conifer
No mineral soir
10-30% mineral
soil6
251 organic soil6
Range fire
Juniper slash
f
Sagebrush'
f
F
S
Fire
6
13
11
F
S
Fire
F
S
Fire
7
14
12
6
16
13
8
15
13
6
17
13
12
19
17
9
25
20
72
226
175
45
166
126
2.3
7.2
5.6
1.5
7.7
5.7
2.1
4.2
3.5
1.7
5.4
4.2
7
14
12
8
15
13
6
17
13
4
7
4
-
~
8
13
10
16
15
15
13
20
18
12
19
17
9
25
20
5
14
6
25
35
11
18
14
23
23
23
44
146
112
2.1
8.0
6.1
F
S
Fire
S
S
4
6
4
_
-
4
7
4
_
-
5
14
6
25
35
28
116
37
200
250
1.0
8.7
1.8
_
-
3.8
7.7
6.4
F
S
Fire
F
S
Fire
7
12
9
15
13
13
8
13
10
16
15
15
11
18
14
23
23
23
41
125
82
78
106
103
2.0
10.3
6.0
3.7
6.2
6.2
2.7
7.8
5.2
3.4
7.3
6.9
33
67
33
67
33
67
90
10
A
A
A
B
B
B
B
B
B
D
D
B
B
B
B
B
B
-------
*> TABLE 11.1-3. EMISSION FACTORS FOR PRESCRIBED BURNING (cont.)a
VO
o
Fire/fuel Phase Pollutant fg/kgl ' Fuel Emission
configuration mix Factor
Participate Carbon Volatile Organics (%) Rating
monoxide
PH, 5 PH1Q Total Methane Nonmethane
Line fire
Conifer
in
O
(D
(D
o
en
O
C
O
Long needle (pine)
Palmetto/gallberry^
Chaparral"
Grasslands?
Heading?
Backing"1
Heading
Back
Fire
Heading
Fire
40
20
15
15
8
to
22
8 9
10
50
20
17
15
-
15
10
200
125
150
100
_
62 2.8 3.5
75
D
D
D
D
D
C
D
2 References 7-8. Unless otherwise noted, determined by field testing of fires > 1 acre size.
F = flaming. S = smoldering. Fire = weighted average of F and S. Dash = no data.
^For PH10, Reference 7. Emission Factor Rating: C.
PM10, Reference 3,7. Emission Factor Rating: C.
For PM1Q, Reference 3,7. Emission Factor Rating: D.
JReference 12. Determined using laboratory combustion hood.
fn
e
Reference 16.
^References 1
.References 1
^Reference 7.
^References 13-14. Determined using laboratory combustion hood.
^References 13-14.
-------
TABLE 11.1-4. EMISSION FACTORS FOR PRESCRIBED BURNING
BY U. S. REGION
Regional
configuration and
fuel type8
Pacific Northwest
Logging slash
Piled slash
Douglas fir/
Western hemlock
Mixed conifer
Ponderosa pine
Hardwood
Underburning pine
Average for region
Pacific Southwest
Sagebrush
Chaparral
Pi nyoa/ Juniper
Underburing pine
Grassland
Average for region
Southeast
Palmetto/ gallberry
Underburning pine
Logging slash
Grassland
Other
Average for region
Rocky Mountain
Logging slash
Underburning pine
Grassland
Other
Average for region
North Central and Eastern
Logging slash
Grassland
Underburning pine
Other
Average for region
Percent
of fuelb
42
24
19
6
4
5
100
35
20
20
15
10
100
35
30
20
10
5
100
50
20
20
10
100
50
30
10
10
100
Pollutant6
Particulate
(g/kg)
«»2.5
4
12
12
13
11
30
9.4
8
n»io
5
13
13
13
12
30
10.3
9
9
13
30
10
13.0
15
30
13
10
17
18.8
4
30
10
17
11.9
13
10
30
17
14
PM
6
17
17
20
18
35
13.3
15
15
17
35
10
17.8
16
35
20
10
17
21.9
6
35
10
17
13.7
17
10
35
17
16.5
CO
37
-*
175
175
126
112
163
111.1
62
62
175
163
75
101.0
125
163
126
75
175
134
37
163
75
175
83.4
175
75
163
175
143.8
aRegional areas are generalized, e. g., the Pacific Northwest includes
Oregon, Washington and parts of Idaho and California. Fuel types
generally reflect the ecosystems of a region, but users should seek
advice on fuel type mix for a given season of the year. An average
factor for Northern California could be more accurately described as
chaparral, 25Z; Underburning pine, 15Z; sagebrush, 15Z; grassland,
5Z; mixed conifer, 25Z; and Douglas fir/Western hemlock, 15Z.
Dash " no data.
bBased on the judgment of forestry experts.
cAdapted from Table 11.1-3 for the dominant fuel types burned.
11.1-10
EMISSION FACTORS
9/90
-------
References for Section 11.1
1. Development Of Emission Factors For Estimating Atmospheric Emissions From
Forest Fires, EPA-450/3-73-009, U. S. Environmental Protection Agency,
Research Triangle Park, NC, October 1973.
2. D. E. Ward and C. C. Hardy, Advances In The Characterization And Control
: Of Emissions From Prescribed Broadcast Fires Of Coniferous Species Logging
Slash On Clearcut Units, EPA DW12930110-01-3/DOE DE-A179-83BP12869, U. S.
Forest Service, Seattle, WA, January 1986.
3. L. F. Radke, et al., Airborne Monitoring And Smoke Characterization Of
Prescribed Fires On Forest Lands In Western Washington and Oregon,
EPA-600/X-83-047, U. S. Environmental Protection Agency, Cincinnati, OH,
July 1983.
4. H. E. Mobley, et al., A Guide For Prescribed Fire In Southern Forests,
U. S. Forest Service, Atlanta, GA, 1973.
5. Southern Forestry Smoke Management Guidebook, SE-10, U. S. Forest Service,
Asheville, NC, 1976.
6. D. E. Ward and C. C. Hardy, "Advances In The Characterization And Control
Of Emissions From Prescribed Fires", Presented at the 77th Annual Meeting
of the Air Pollution Control Association, San Francisco, CA, June 1984.
7. C. C. Hardy and D. E. Ward, "Emission Factors For Particulate Matter By
Phase Of Combustion From Prescribed Burning", Presented at the Annual
Meeting of the Air Pollution Control Association Pacific Northwest
International Section, Eugene, OR, November 19-21, 1986.
8. D. V. Sandberg and R. D. Ottmar, "Slash Burning And Fuel Consumption In
The Douglas Fir Subregion", Presented at the 7th Conference On Fire And
Forest Meteorology, Fort Collins," CO, April 1983.
9. D. V. Sandberg, "Progress In Reducing Emissions From Prescribed Forest
Burning In Western Washington And Western Oregon", Presented at the Annual
Meeting of the Air Pollution Control Association Pacific Northwest
International Section, Eugene, OR, November 19-21, 1986.
10. R. D. Ottmar and D. V. Sandberg, "Estimating 1000-hour Fuel Moistures In
The Douglas Fir Subregion", Presented at the 7th Conference On Fire And
Forest Meteorology, Fort Collins, CO, April 25-28, 1983.
11. D. V. Sandberg, et al. , Effects Of Fire On Air - A State Of Knowledge
Review. WO-9, U. S. Forest Service, Washington, DC, 1978.
12. C. K. McMahon, "Characteristics Of Forest Fuels, Fires, And Emissions",
Presented at the 76th Annual Meeting of the Air Pollution Control
Association, Atlanta, GA, June 1983.
13. D. E. Ward, "Source Strength Modeling Of Particulate Matter Emissions From
Forest Fires", Presented at the 76th Annual Meeting of the Air Pollution
Control Association, Atlanta, GA, June 1983.
9/90 Miscellaneous Sources 11.1-11
-------
14. D. E. Ward, et al.. "Particulate Source Strength Determination For Low-
intensity Prescribed Fires", Presented at the Agricultural Air
Pollutants Specialty Conference, Air Pollution Control Association,
Memphis, TN, March 18-19, 1974.
15. Prescribed Fire Smoke Management Guide. 420-1, BIFC-BLM Warehouse,
Boise, ID, February 1985.
16. Colin C. Hardy, Emission Factors For Air Pollutants From Range
Improvement Prescribed Burning Of Western Juniper And Basin Big
Sagebrush. PNW 88-575, Office Of Air Quality Planning And Standards,
U. S. Environmental Protection Agency, Research Triangle Park, NC,
March 1990.
11.1-12 EMISSION FACTORS 9/90
-------
11.2.6 INDUSTRIAL PAVED ROADS
11.2.6.1 General
Various field studies have indicated that dust emissions from industrial
paved roads are a major component of atmospheric particulate matter in the
vicinity of industrial operations. Industrial traffic dust has been found to
consist primarily of mineral matter, mostly tracked or deposited onto the road-
way by vehicle traffic itself, when vehicles enter from an unpaved area or
travel on the shoulder of the road, or when material is spilled onto the paved
surface from open truck bodies.
11.2.6.2 Emissions And Correction Parameters*^
The quantity of dust emissions from a given segment of paved road varies
linearly with the volume of traffic. In addition, field investigations have
shown that emissions depend on correction parameters (road surface silt content,
surface dust loading and average vehicle weight) of a particular road and asso-
ciated vehicle traffic.
Dust emissions from industrial paved roads have been found to vary in
direct proportion to the fraction of silt (particles equal to or less than 75
microns in diameter) in the road surface material. The silt fraction is deter-
mined by measuring the proportion of loose dry surface dust that passes a 200
mesh screen, using the ASTM-C-136 method. In addition, it has also been found
that emissions vary in direct proportion to the surface dust loading. The road
surface dust loading is that loose material which can be collected by broom
sweeping and vacuuming of the traveled portion of the paved road. Table 11.2.6-1
summarizes measured silt and loading values for industrial paved roads.
11.2.6.3 Predictive Emission Factor Equations
The quantity of total suspended particulate emissions generated by vehicle
traffic on dry industrial paved roads, per vehicle kilometer traveled (VKT) or
vehicle mile traveled (VMT), may be estimated with a rating of B or D (see
below), using the following empirical expression^:
0.0221 (kg/VKT) (1)
s
/ L \/W\0-7
0.0771 [ 1 I I jf —| (Ib/VMT)
10 / VlOOO/l 3 I
where: E = emission factor
I = industrial augmentation factor (dimensionless) (see below)
n = number of traffic lanes
s = surface material silt content (%)
L = surface dust loading, kg/km (Ib/mile) (see below)
W = average vehicle weight, Mg (ton)
11/88 Miscellaneous Sources 11.2.6-1
-------
N)
I
ro
TABLE 11.2.6-1. TYPICAL SILT CONTENT AND LOADING VALUES FOR
PAVED ROADS AT INDUSTRIAL FACILITIESa
Industry
Copper
smelting
Iron and
steel
production
Asphalt
batching
Concrete
batching
Sand and
gravel
processing
No.
of
sites
1
6
1
1
1
No.
of
samples
3
20
3
3
3
Silt (wgt. %)
Range Mean
15.4 - 21.7 19.0
1.1 - 35.7 12.5
2.6 - 4.6 3.3
5.2 - 6.0 5.5
6.4 - 7.9 7.1
No. of
travel
lanes
2
2
1
2
1
Total loading x 10~3
Range Mean Units0
12.9 - 19.5 15.9 kg/km
45.8 - 69.2 55.4 Ib/mi
0.006 - 4.77 0.495 kg/km
0.020 - 16.9 1.75 Ib/mi
12.1 - 18.0 14.9 kg/km
43.0 - 64.0 52.8 Ib/mi
1.4 - 1.8 1.7 kg/km
5.0 - 6.4 5.9 Ib/mi
2.8 - 5.5 3.8 kg/km
9.9 - 19.4 13.3 Ib/mi
Silt loading
(g/m2)
Range Mean
188 - 400 292
0.09 - 79 12
76 - 193 120
11 - 12 12
53 - 95 70
on
on
o
z
o
H
O
?o
on
a References 1-5.
b Multiply entries by 1,000 to obtain stated units.
vO
00
oo
-------
11.2.7 INDUSTRIAL WIND EROSION
11.2.7.1 General1'3
Dust emissions may be generated by wind erosion of open aggregate storage
piles and exposed areas within an industrial facility. These sources
typically are characterized by nonhomogeneous surfaces impregnated with
nonerodible elements (particles larger than approximately 1 centimeter (cm) in
diameter). Field testing of coal piles and other exposed materials using a
portable wind tunnel has shown that (a) threshold wind speeds exceed 5 meters
per second (11 miles per hour) at 15 centimeters above the surface or 10
meters per second (22 miles per hour) at 7 meters above the surface, and (b)
particulate emission rates tend to decay rapidly (half life of a few minutes)
during an erosion event. In other words, these aggregate material surfaces
are characterized by finite availability of erodible material (mass/area)
referred to as the erosion potential. Any natural crusting of the surface
binds the erodible material, thereby reducing the erosion potential.
11.2.7.2 Emissions And Correction Parameters
If typical values for threshold wind speed at 15 centimeters are
corrected to typical wind sensor height (7-10 meters), the resulting values
exceed the upper extremes of hourly mean wind speeds observed in most areas of
the country. In other words, mean atmospheric wind speeds are not sufficient
to sustain wind erosion from flat surfaces of the type tested. However, wind
gusts may quickly deplete a substantial portion of the erosion potential.
Because erosion potential has been found to increase rapidly with increasing
wind speed, estimated emissions should be related to the gusts of highest
magnitude.
The routinely measured meteorological variable which best reflects the
magnitude of wind gusts is the fastest mile. This quantity represents the
wind speed corresponding to the whole mile of wind movement which has passed
by the 1 mile contact anemometer in the least amount of time. Daily
measurements of the fastest mile are presented in the monthly Local
Climatological Data (LCD) summaries. The duration of the fastest mile,
typically about 2 minutes (for a fastest mile of 30 miles per hour), matches
well with the half life of the erosion process, which ranges between 1 and 4
minutes. It should be noted, however, that peak winds can significantly
exceed the daily fastest mile.
The wind speed profile in the surface boundary layer is found to follow
a logarithmic distribution:
u(z) = u*_ In z_ (z > ZQ) (1)
0.4 z0
where u = wind speed, centimeters per second
u* = friction velocity, centimeters per second
z = height above test surface, cm
zQ = roughness height, cm
0.4 = von Karman's constant, dimensionless
9/90 Miscellaneous Sources 11.2.7-1
-------
The friction velocity (u*) is a measure of wind shear stress on the erodible
surface, as determined from the slope of the logarithmic velocity profile.
The roughness height (zo) is a measure of the roughness of the exposed surface
as determined from the y intercept of the velocity profile, i. e., the height
at which the wind speed is zero. These parameters are illustrated in Figure
11.2.7-1 for a roughness height of 0.1 centimeters.
Emissions generated by wind erosion are also dependent on the frequency
of disturbance of the erodible surface because each time that a surface is
disturbed, its erosion potential is restored. A disturbance is defined as an
action which results in the exposure of fresh surface material. On a storage
pile, this would occur whenever aggregate material is either added to or
removed from the old surface. A disturbance of an exposed area may also
result from the turning of surface material to a depth exceeding the size of
the largest pieces of material present.
11.2.7.3 Predictive Emission Factor Equation^
The emission factor for wind generated particulate emissions from
mixtures of erodible and nonerodible surface material subject to disturbance
may be expressed in units of grams per square meter per year as follows:
N
Emission factor = k S P (2)
where k = particle size multiplier
N = number of disturbances per year
P^ = erosion potential corresponding to the observed (or
probable) fastest mile of wind for the ith period
between disturbances, g/m^
The particle size multiplier (k) for Equation 2 varies with aerodynamic
particle size, as follows:
AERODYNAMIC PARTICLE SIZE MULTIPLIERS FOR EQUATION 2
30 urn <15 urn <10 pm <2 . 5 ^m
1.0 0.6 0.5 0.2
This distribution of particle size within the under 30 micron fraction
is comparable to the distributions reported for other fugitive dust sources
where wind speed is a factor. This is illustrated, for example, in the
distributions for batch and continuous drop operations encompassing a number
of test aggregate materials (see Section 11.2.3).
In calculating emission factors, each area of an erodible surface that
is subject to a different frequency of disturbance should be treated
separately. For a surface disturbed daily, N = 365 per year, and for a
surface disturbance once every 6 months, N = 2 per year.
11.2.7-2 EMISSION FACTORS 9/90
-------
vO
H-
OP
w
o
(D
P>
O
(0
o
o
0)
(0
c
en
rt
H-
o
3
o
H)
o
-------
The erosion potential function for a dry, exposed surface is:
P = 58 (u* - u*)2 + 25 (u* - u*)
t t
P = 0 for u* < u*
t
where u* = friction velocity (m/s)
*
(3)
u
threshold friction velocity (m/s)
Because of the nonlinear form of the erosion potential function, each
erosion event must be treated separately.
Equations 2 and 3 apply only to dry, exposed materials with limited
erosion potential. The resulting calculation is valid only for a time period
as long or longer than the period between disturbances. Calculated emissions
represent intermittent events and should not be input directly into dispersion
models that assume steady state emission rates.
For uncrusted surfaces, the threshold friction velocity is best
estimated from the dry aggregate structure of the soil. A simple hand sieving
test of surface soil can be used to determine the mode of the surface
aggregate size distribution by inspection of relative sieve catch amounts,
following the procedure described below in Table 11.2.7.-1. Alternatively,
the threshold friction velocity for erosion can be determined from the mode of
the aggregate size distribution, as described by Gillette. ""
Threshold friction velocities for several surface types have been
determined by field measurements with a portable wind tunnel. These values
are presented in Table 11.2.7-2.
TABLE 11.2.7-1. FIELD PROCEDURE FOR DETERMINATION OF
THRESHOLD FRICTION VELOCITY
Tyler
sieve no.
5
9
16
32
60
Opening
(mm)
4
2
1
0.5
0.25
Midpoint
(mm)
3
1.5
0.75
0.375
u (cm/sec)
t
100
72
58
43
11.2.7-4
EMISSION FACTORS
9/90
-------
FIELD PROCEDURE FOR DETERMINATION OF THRESHOLD FRICTION VELOCITY
(from a 1952 laboratory procedure published by W. S. Chepil):
1. Prepare a nest of sieves with the following openings: 4 mm, 2 mm, 1 mm,
0.5 mm, 0.25 mm. Place a collector pan below the bottom (0.25 mm)
sieve.
2. Collect a sample representing the surface layer of loose particles
(approximately 1 cm in depth, for an encrusted surface), removing any
rocks larger than about 1 cm in average physical diameter. The area to
be sampled should be not less than 30 cm.
3. Pour the sample into the top sieve (4 mm opening), and place a lid on
the top.
4. Move the covered sieve/pan unit by hand, using a broad circular arm
motion in the horizontal plane. Complete 20 circular movements at a
speed just necessary to achieve some relative horizontal motion between
the sieve and the particles.
5. Inspect the relative quantities of catch within each sieve, and
determine where the mode in the aggregate size distribution lies, i. e.,
between the opening size of the sieve with the largest catch and the
opening size of the next largest sieve.
6. Determine the threshold friction velocity from Figure 1.
The fastest mile of wind for the periods between disturbances may be obtained
from the monthly LCD summaries for the nearest reporting weather station that
is representative of the site in question. These summaries report actual
fastest mile values for each day of a given month. Because the erosion
potential is a highly nonlinear function of the fastest mile, mean values of
the fastest mile are inappropriate. The"anemometer heights of reporting
weather stations are found in Reference 8, and should be corrected to a
10 meter reference height using Equation 1.
To convert the fastest mile of wind (u+) from a reference anemometer
height of 10 meters to the equivalent friction velocity (u*), the logarithmic
wind speed profile may be used to yield the following equation:
u* = 0.053 u+ (4)
where u* = friction velocity (meters per second)
u'+ = fastest mile of reference anemometer for period
1 between disturbances (meters per second)
This assumes a typical roughness height of 0.5 cm for open terrain.
Equation 4 is restricted to large relatively flat piles or exposed areas with
little penetration into the surface wind layer.
9/90 Miscellaneous Sources 11.2.7-5
-------
TABLE 11.2.7-2. THRESHOLD FRICTION VELOCITIES
Threshold
friction
velocity
Material
Overburden3
Scoria (roadbed
material )a
Ground coala
( surrounding
coal pile)
Uncrusted coal
pile3
Scraper tracks on
coal pilea>k
Fine coal dust
on concrete padc
(m/s)
1
1
0
1
0
0
.02
.33
.55
.12
.62
.54
Roughness
height
(cm)
0.
0.
0.
0.
0.
0.
3
3
01
3
06
2
Threshold wind
velocity at 10 m (m/s)
ZQ = Act
21
27
16
23
15
11
ZQ = 0.5 cm
19
25
10
21
12
10
aWestern surface coal mine. Reference 2.
Lightly crusted.
cEastern power plant. Reference 3.
If the pile significantly penetrates the surface wind layer (i. e., with
a height-to-base ratio exceeding 0.2), it is necessary to divide the pile area
into subareas representing different degrees of exposure to wind. The results
of physical modeling show that the frontal face of an elevated pile is exposed
to wind speeds of the same order as the approach wind speed at the top of the
pile.
For two representative pile shapes (conical and oval with flattop,
37 degree side slope), the ratios of surface wind speed (ug) to approach wind
speed (ur) have been derived from wind tunnel studies. The results are shown
in Figure 11.2.7-2 corresponding to an actual pile height of 11 meters, a
reference (upwind) anemetersometer height of 10 meters, and a pile surface
roughness height (z ) of 0.5 centimeters. The measured surface winds
correspond to a height of 25 centimeters above the surface.
within each contour pair is specified in Table 11.2.7-3.
The area fraction
The profiles of ug/ur in Figure 11.2.7-2 can be used to estimate the
surface friction velocity distribution around similarly shaped piles, using
the following procedure:
1. Correct the fastest mile value (u+) for the period of interest from
the anemometer height (z) to a reference height of 10 m (u+n) using
a variation of Equation 1:
10
u+ =
10
u
In (10/0.005)
In (z/0.005)
(5)
where a typical roughness height of 0.5 cm (0.005 meters) has been
assumed. If a site specific roughness height is available, it
should be used.
11.2.7-6
EMISSION FACTORS
9/90
-------
2. Use the appropriate part of Figure 11.2.7-2 based on the pile shape
and orientation to the fastest mile of wind, to obtain the
corresponding surface wind speed distribution (u+):
s
u+ = -— u+ (6)
ur 10
3. For any subarea of the pile surface having a narrow range of
surface wind speed, use a variation of Equation 1 to calculate the
equivalent friction velocity (u*):
0.4 u+
s
u* - = 0.10 u+
25. s
lnO.5
From this point on, the procedure is identical to that used for a flat
pile, as described above.
Implementation of the above procedure is carried out in the following
steps:
1. Determine threshold friction velocity for erodible material of
interest (see Table 11.2.7-2 or determine from mode of aggregate
size distribution).
2. Divide the exposed surface area into subareas of constant frequency
of disturbance (N).
3. Tabulate fastest mile values (u+) for each frequency of disturbance
and correct them to 10 m (u+ ) using Equation 5.
10
4. Convert fastest mile values (U^Q) to equivalent friction velocities
(u*), taking into account (a) the uniform wind exposure of
nonelevated surfaces, using Equation 4, or (b) the nonuniform wind
exposure of elevated surfaces (piles), using Equations 6 and 7.
5. For elevated surfaces (piles), subdivide areas of constant N into
subareas of constant u* (i. e., within the isopleth values of
in Figure 11.2.7-2 and Table 11.2.7-3) and determine the size of
each subarea.
6. Treating each subarea (of constant N and u*) as a separate source,
calculate the erosion potential (P^) for each period between
disturbances using Equation 3 and the emission factor using
Equation 2.
7. Multiply the resulting emission factor for each subarea by the size
of the subarea, and add the emission contributions of all subareas.
Note that the highest' 24-hr emissions would be expected to occur on
the windiest day of the year. Maximum emissions are calculated
assuming a single event with the highest fastest mile value for the
annual period.
9/90 Miscellaneous Sources 11.2.7-7
-------
Flow
Direction
Pile A
Pile B1
Pile B2
Pile B3
Figure 11.2.7-2. Contours of normalized surface wind speeds, us/ur.
11.2.7-8 EMISSION FACTORS 9/90
-------
TABLE 11.2.7-3. SUBAREA DISTRIBUTION FOR REGIMES OF us/ur
Pile
Subarea
0.2a
0.2b
0.2c
0.6a
0.6b
0.9
1.1
Percent of pile surface area
Pile A
5
35
-
48
-
12
-
Pile Bl
5
2
29
26
24
14
-
Pile B2
3
28
-
29
22
15
3
Pile B3
3
25
-
28
26
14
4
The recommended emission factor equation presented above assumes that all
of the erosion potential corresponding to the fastest mile of wind is lost
during the period between disturbances. Because the fastest mile event
typically lasts only about 2 minutes, which corresponds roughly to the
halflife for the decay of actual erosion potential, it could be argued that
the emission factor overestimates particulate emissions. However, there are
other aspects of the wind erosion process which offset this apparent
conservatism:
1. The fastest mile event contains peak winds which substantially
exceed the mean value for the event.
2. Whenever the fastest mile event occurs, there are usually a number
of periods of slightly lower mean wind speed which contain peak
gusts of the same order as the fastest mile wind speed.
Of greater concern is the likelihood of overprediction of wind erosion
emissions in the case of surfaces disturbed infrequently in comparison to the
rate of crust formation.
11.2.7.4 Example 1: Calculation for wind erosion emissions from conically
shaped coal pile
A coal burning facility maintains a conically shaped surge pile 11 meters
in height and 29.2 meters in base diameter, containing about 2000 megagrams of
coal, with a bulk density of 800 kg/m3 (50 lb/ft3). The total exposed surface
area of the pile is calculated as follows:
S = TT r (r2 + h2)
= 3.14(14.6) (14.6)2 +(11.0)2
= 838 m2
Coal is added to the pile by means of a fixed stacker and reclaimed by
front-end loaders operating at the base of the pile on the downwind side. In
addition, every 3 days 250 megagrams (12.5 percent of the stored capacity of
coal) is added back to the pile by a topping off operation, thereby restoring
«
9/90 Miscellaneous Sources 11.2.7-9
-------
the full capacity of the pile. It is assumed that (a) the reclaiming
operation disturbs only a limited portion of the surface area where the daily
activity is occurring, such that the remainder of the pile surface remains
intact, and (b) the topping off operation creates a fresh surface on the
entire pile while restoring its original shape in the area depleted by daily
reclaiming activity.
Because of the high frequency of disturbance of the pile, a large number
of calculations must be made to determine each contribution to the total
annual wind erosion emissions. This illustration will use a single month as
an example.
Step 1: In the absence of field data for estimating the threshold
friction velocity, a value of 1.12 meters per second is obtained from Table
11.2.7-2.
Step 2: Except for a small area near the base of the pile (see Figure
11.2.7-3), the entire pile surface is disturbed every 3 days, corresponding to
a value of N = 120 per year. It will be shown that the contribution of the
area where daily activity occurs is negligible so that it does not need to be
treated separately in the calculations.
Step 3: The calculation procedure involves determination of the fastest
mile for each period of disturbance. Figure 11.2.7-4 shows a representative
set of values (for a 1-month period) that are assumed to be applicable to the
geographic area of the pile location. The values have been separated into 3-
day periods, and the highest value in each period is indicated. In this
example, the anemometer height is 7 meters, so that a height correction to
10 meters is needed for the fastest mile values. From Equation 5,
u+
In (10/0.005)
10 7 1 In (7/0.005)
u+ = 1.05 u+
10 7
Step 4: The next step is to convert the fastest mile value for each 3
day period into the equivalent friction velocities for each surface wind
regime (i. e., us/ur ratio) of the pile, using Equations 6 and 7. Figure
11.2.7-3 shows the surface wind speed pattern (expressed as a fraction of the
approach wind speed at a height of 10 meters). The surface areas lying within
each wind speed regime are tabulated below the figure.
The calculated friction velocities are presented in Table 11.2.7-4. As
indicated, only three of the periods contain a friction velocity which exceeds
the threshold value of 1.12 meters per second for an uncrusted coal pile.
These three values all occur within the Ug/Uj. = 0.9 regime of the pile
surface.
Step 5: This step is not necessary because there is only one frequency
of disturbance used in the calculations. It is clear that the small area of
daily disturbance (which lies entirely within the us/ur =0.2 regime) is never
subject to wind speeds exceeding the threshold value.
11.2.7-10 EMISSION FACTORS 9/90
-------
Prevailing
Wind
Direction
Circled values
refer to
* A portion of C2 i-s disturbed daily by reclaiming activities.
Pile Surface
Area u
ID -rqr
A 0.9
B 0.6
C-L + C2 0.2
%
12
48
40
9
Area (m )
101
402
335
Total 838
Figure 11.2.7-3. Example 1: Pile surface areas within each wind
speed regime.
9/90
Miscellaneous Sources
11.2.7-11
-------
TABLE 11.2.7-4. EXAMPLE 1: CALCULATION OF FRICTION VELOCITIES
3 -day
period
1
2
3
4
5
6
7
8
9
10
(mph)
14
29
30
31
22
21
16
25
17
13
U7
(m/s)
6.3
13.0
13.4
13.9
9.8
9.4
7.2
11.2
7.6
5.8
U10
(mph)
'15
31
32
33
23
22
17
26
18
14
(m/s)
6.6
13.7
14.1
14.6
10.3
9.9
7.6
11.8
8.0
6.1
u* =
us/ur: 0.2
0.13
0.27
0.28
0.29
0.21
0.20
0.15
0.24
0.16
0.12
0.1 us
0.6
0.40
0.82
0.84
0.88
0.62
0.59
0.46
0.71
0.48
0.37
(m/s)
0.9
0.59
1.23
1.27
1.31
0.93
0.89
0.68
1.06
0.72
0.55
Steps 6 and 7: The final set of calculations (shown in Table 11.2.7-5)
involves the tabulation and summation of emissions for each disturbance period
and for the affected subarea. The erosion potential (P) is calculated from
Equation 3.
TABLE 11.2.7-5. EXAMPLE 1: CALCULATION OF PM1Q EMISSIONS3
3 -day
period u* (m/s)
2 1.23
3 1.27
4 1.31
"Jc
u* - u (m/s)
0.11
0.15
0.19
P (g/m2)
3.45
5.06
6.84
Pile
Surface Area
ID (m2)
A
A
A
101
101
101
kPA
(g)
170
260
350
Total:
780
awhere u =1.12 meters per second for uncrusted coal and k = 0.5 for PM^Q.
For example, the calculation for the second 3 day period is:
P = 58(u* - u*)2 + 25(u* - u*)
P2 = 58(1.23 - 1.12)2 + 25(1.23 - 1.12)
= 0.70 + 2.75 = 3.45 g/m2
The PM-^Q emissions generated by each event are found as the product of
the PM-^o multiplier (k = 0.5), the erosion potential (P), and the affected
area of the pile (A).
11.2.7-12
EMISSION FACTORS
9/90
-------
Local Climatological Data
MON1HLY SUMMARY
WIND
.
cr
o
^»
z
i
^J
^
t/1*
h*>
a
13
30
0
10
13
12
20
29
29
22
1 4
29
17
21
10
10
01
33
27
32
24
22
32
29
07
34
31
30
30
33
34
29
.
x
*- o.
z
rf
_) O
S k*J
t/1 U
l*J CX
i"y 4/»
14
5.3
10.5
2.4
1 1 .0
1 1 .3
1 . 1
19.6
10.9
3.0
14.6
22.3
7.9
7.7
4.5
6.7
13.7
1 1 .2
4.3
9.3
7.5
10.3
17.1
2.4
5.9
11.3
12. 1
8.3
8.2
5.0
3. 1
4.9
o
UJ
a.
trt
o at
£= a.
t._j
•>• ac
"*
15
6.9
FASTEST
HILE
^
o
v— i a.
L«> •
o. z;
16
J
10.61 (ij)
6.0 10
1 1 .4 1 16
11.9 15
19.0
19.8
1 .2
8. 1
15. 1
23.3
ft
1 7
15
2J
©
13.5 23
is.srTT
9.6 £}
8.8
13.8
1 1 .5
5.8
10.2
7.8
z
0
_
0
UJ
cr
o
17
36
01
02
13
1 1
30
30
30
13
12
29
17
18
13
-^ "
^Jl 36
T« 34
j 2
1 4
(Tb
10.6 16
17.3 jc¥
8.51 P4
31
35
24
20
32
13
8.8 15 02
1 .7 1 QJ)I 32
12.2 16 32
8.51161 26
g . 3 1 QJI 32
6.6 rO 32
5.2 9_l 31
5.5 1 Si 25
FOP THE MONTH;
30
—
3.3
I . I
C
31 1 29
ATE: 1 1
k*J
^_
^
0
22
i
2
3
4
5
6
7
g
9
10
i
12
3
1 1,
15
16
17
16
"19
20
21
22
23
24
25
26
27
22
29
30
31
Figure 11.2.7-4. Example daily fastest miles of wind for periods of interest,
9/90
Miscellaneous Sources
11.2.7-13
-------
As shown in Table 11.2.7-5, the results of these calculations indicate a
monthly PM^o emissi-on total of 780 grams.
11.2.7.5 Example 2: Calculation for wind erosion from flat area covered
with coal dust
A flat circular area of 29.2 meters in diameter is covered with coal dust
left over from the total reclaiming of a conical coal pile described in the
example above. The total exposed surface area is calculated as follows:
7T
S = - d2 = 0.785 (29. 2)2 = 670 m2
This area will remain exposed for a period of 1 month when a new pile
will be formed.
Step 1: In the absence of field data for estimating the threshold
friction velocity, a value of 0.54 m/s is obtained from Table 11.2.7-2.
Step 2: The entire surface area is exposed for a period of 1 month after
removal of a pile and N = 1/yr.
Step 3: From Figure 11.2.7-4, the highest value of fastest mile for the
30-day period (31 mph) occurs on the llth day of the period. In this example,
the reference anemometer height is 7 m, so that a height correction is needed
for the fastest mile value. From Step 3 of the previous example,
u+ = 1.05 u+ -, so that u+ = 33 mph.
10 7 10
Step 4: Equation 4 is used to convert the fastest mile value of 33 mph
(14.6 mps) to an equivalent friction velocity of 0.77 mps. This value exceeds
the threshold friction velocity from Step 1 so that erosion does occur.
Step 5: This step is not necessary, because there is only one frequency
of disturbance for the entire source area.
Steps 6 and 7: The PM^g emissions generated by the erosion event are
calculated as the product of the PM^Q multiplier (k = 0.5), the erosion
potential (P) and the source area (A). The erosion potential is calculated
from Equation 3 as follows:
P = 58(u* - u*)2 + 25(u* - u*)
t t
P - 58(0.77 - 0.54)2 + 25(0.77 - 0.54)
= 3.07 + 5.75
=8.82 g/m2
Thus the PM^Q emissions for the 1 month period are found to be:
E = (0.5)(8.82 g/m2)(670 m2)
= 3.0 kg
11.2.7-14 EMISSION FACTORS 9/90
-------
References for Section 11.2.7
1. C. Cowherd Jr., "A New Approach To Estimating Wind Generated Emissions
From Coal Storage Piles", Presented at the APCA Specialty Conference on
Fugitive Dust Issues in the Coal Use Cycle, Pittsburgh, PA, April 1983.
2. K. Axtell and C. Cowherd, Jr., Improved Emission Factors For Fugitive
Dust From Surface Coal Mining Sources. EPA-600/7-84-048, U. S.
Environmental Protection Agency, Cincinnati, OH, March 1984.
3. G. E, Muleski, "Coal Yard Wind Erosion Measurement", Midwest Research
Institute, Kansas City, MO, March 1985.
4. Update Of Fugitive Dust Emissions Factors In AP-42 Section 11.2 - Wind
Erosion. MRI No. 8985-K, Midwest Research Institute, Kansas City, MO,
1988.
5. W. S. Chepil, "Improved Rotary Sieve For Measuring State And Stability Of
Dry Soil Structure", Soil Science Society Of America Proceedings.
16:113-117, 1952.
6. D. A. Gillette, et al. . "Threshold Velocities For Input Of Soil Particles
Into The Air By Desert Soils", Journal Of Geophysical Research.
85(C10_): 5621-5630.
7. Local Climatological Data, National Climatic Center, Asheville, NC.
8. M. J. Changery, National Wind Data Index Final Report. HCO/T1041-01
UC-60, National Climatic Center, Asheville, NC, December 1978.
9. B. J. B. Stunder and S. P. S. Arya, "Windbreak Effectiveness For Storage
Pile Fugitive Dust Control: A Wind Tunnel Study", Journal Of The Air
Pollution Control Association. 38:135-143, 1988.
9/90 Miscellaneous Sources 11.2.7-15
-------
11.3 EXPLOSIVES DETONATION
11.3.1 General 1~5
This section deals mainly with pollutants resulting from the
detonation of industrial explosives and firing of small arms. Military
applications are excluded from this discussion. Emissions associated
with the manufacture of explosives are treated in Section 5.6,
Explosives.
An explosive is a chemical material that is capable of extremely
rapid combustion resulting in an explosion or detonation. Since an
adequate supply of oxygen cannot be drawn from the air, a source of
oxygen must be incorporated into the explosive mixture. Some explo-
sives, such as trinitrotoluene (TNT), are single chemical species, but
most explosives are mixtures of several ingredients. "Low explosive"
and "high explosive" classifications are based on the velocity of
explosion, which is directly related to the type of work the explosive
can perform. There appears to be no direct relationship between the
velocity of explosions and the end products of explosive reactions.
These end products are determined primarily by the oxygen balance of the
explosive. As in other combustion reactions, a deficiency of oxygen
favors the formation of carbon monoxide and unburned organic compounds
and produces little, if any, nitrogen oxides. An excess of oxygen
causes more nitrogen oxides and less carbon monoxide and other unburned
organics. For ammonium nitrate and fuel oil mixtures (ANFO), a fuel oil
content of more than 5.5 percent creates a deficiency of oxygen.
There are hundreds of different explosives, with no universally
accepted system for classifying them. The classification used in Table
11.3-1 is based on the chemical composition of the explosives, without
regard to other to other properties, such as rate of detonation, which
relate to the applications of explosives but not to their specific end
products. Most explosives are used in two-, three-, or four-step trains
that are shown schematically in Figure 11.3-1. The simple removal of a
tree stump might be done with a two-step train made up of an electric
blasting cap and a stick of dynamite. The detonation wave from the
blasting cap would cause detonation of the dynamite. To make a large
hole in the earth, an inexpensive explosive such as ammonium nitrate and
fuel oil (ANFO) might be used. In this case, the detonation wave from
the blasting cap is not powerful enough to cause detonation, so a
booster must be used in a three- or four-step train. Emissions from the
blasting caps and safety fuses used in these trains are usually small
compared to those from the main charge, because the emissions are
roughly proportional to the weight of explosive used, and the main
charge makes up most of the total weight. No factors are given for
computing emissions from blasting caps or fuses, because these have not
been measured, and because the uncertainties are so great in estimating
emissions from the main and booster charges that a precise estimate of
all emissions is not practical.
2/80 Miscellaneous Sources 11.3-1
-------
2. OYNAMITf
1. ELECTRIC
•LASTING CAP
PRIMARY
MICH EXPLOSIVE
SECONDARY NIGH EXPLOSIVE
a. Two-step explosive train
a. DYNAMITE
1. SAFETY FUSE
2. NONELECTRIC
BLASTING CAP
LOW EXPLOSIVE PRIMARY
(BLACK POWDER) HIGH
'EXPLOSIVE
SECONDARY HIGH EXPLOSIVE
b. Three-step explosive train
4. ANFO
LOW PRIMARY TS
EXPLOSIVE HIGH EXPLOSIVE SECONDARY HIGH EXPLOSIVE
X DYNAMITE
BOOSTER
, «««TV *• NONELECTRIC
FUSE W.ASTINC CAP
i n
I
i
i
w
c. Four-step explosive train
Figure 11.3-1. Two-, three-, and four-step explosive trains.
11.3-2
EMISSION FACTORS
2/80
-------
CO
o
Table 11.3-1. EMISSION FACTORS FOR DETONATION OF EXPLOSIVES
(EMISSION FACTOR RATING: D)
2
l-1-
(n
O
CD
3
fl>
O
to
CO
o
n
o
(D
Cfl
Explosive
Black powder?
Smokeless
farter*
Dynamite.
Straight'
Dynamite.
Ammonia2
Dynamite.
Gelatin'
ANFO4-5
TNT2
ROX3
P£TN2
Composition
75/15/10; potassium (sodium)
nitrate/charcoal/sulfur
nitrocellulose (sometimes
with other materials)
30-601 nitroglycerine/
sodium nitrate/wood pulp/
calcium carbonate.
20-601 nitroglycerine/
ammonium nitrate/sodium
nitrate/wood pulp
20-IOOt nitroglycerine
ammonium nitrate with
5.8-8t fuel oil
trinitrotoluene
-------
t / f\
11.3.2 Emissions And Controls '
Carbon monoxide is the pollutant produced in greatest quantity from
explosives detonation. TNT, an oxygen deficient explosive, produces
more CO than most dynamites, which are oxygen balanced. But all explo-
sives produce measurable amounts of CO. Particulates are produced as
well, but such large quantities of particulate are generated in the
shattering of the rock and earth by the explosive that the quantity of
particulates from the explosive charge cannot be distinguished. Nitrogen
oxides (both NO and N02) are formed, but only limited data are available
on these emissions. Oxygen deficient explosives are said to produce
little or no nitrogen oxides, but there is only a small body of data to
confirm this. Unburned hydrocarbons also result from explosions, but in
most instances, methane is the only species that has been reported.
Hydrogen sulfide, hydrogen cyanide and ammonia all have been
reported as products of explosives use. Lead is emitted from the firing
of small arms ammunition with lead projectiles and/or lead primers, but
the explosive charge does not contribute to the lead emissions.
The emissions from explosives detonation are influenced by many
factors such as explosive composition, product expansion, method of
priming, length of charge, and confinement. These factors are difficult
to measure and control in the field and are almost impossible to duplicate
in a laboratory test facility. With the exception of a few studies in
underground mines, most studies have been performed in laboratory test
chambers that differ substantially from the actual environment. Any
estimates of emissions from explosives use must be regarded as approxi-
mations that cannot be made more precise, because explosives are not
used in a precise, reproducible manner.
To a certain extent, emissions can be altered by changing the
composition of the explosive mixture. This has been practiced for many
years to safeguard miners who must use explosives. The U. S. Bureau of
Mines has a continuing program to study the products from explosives and
to identify explosives that can be used safely underground. Lead
emissions from small arms use can be controlled by using jacketed soft
point projectiles and special leadfree primers.
Emission factors are given in Table 11.3-1.
References for Section 11.3
1. C. R. Newhouser, Introduction to Explosives, National Bomb Data
Center, International Association of Chiefs of Police, Gaithersburg,
MD (undated).
2. Roy V. Carter, "Emissions from the Open Burning or Detonation of
Explosives", Presented at the 71st Annual Meeting of the Air
Pollution Control Association, Houston, TX, June 1978.
11-3-4 EMISSION FACTORS 2/80
-------
3. Melvin A. Cook, The Science of High Explosives, Reinhold Publishing
Corporation, New York, 1958.
4. R. F. Chaiken, et al., Toxic Fumes from Explosives; Ammonium
Nitrate Fuel Oil Mixtures, Bureau of Mines Report of Investigations
7867, U. S. Department of Interior, Washington, DC, 1974.
5. Sheridan J. Rogers, Analysis of Noncoal Mine Atmospheres; Toxic
Fumes from Explosives, Bureau of Mines, U. S. Department of Interior,
Washington, DC, May 1976.
6. A. A. Juhasz, "A Reduction of Airborne Lead in Indoor Firing
Ranges by Using Modified Ammunition", Special Publication 480-26,
Bureau of Standards, U. S. Department of Commerce, Washington, DC,
November 1977.
2/80 Miscellaneous Sources 11.3-5
-------
TABLE C.2-1. PARTICLE SIZE CATEGORY BY AP-42 SECTION
AP-42
Section
1.1
1.2
1.3
1.4
1.5
1.6
1.7
1.8
1.9
1.10
1.11
2.1
2.3
2.5
32
5.4
5.8
5.10
5.11
5.12
5.15
5.16
5.17
6.1
6.2
6.3
6.4
6.5
6.7
Source
Category
External combustion
Bituminous and subbituminous
coal combustion
Anthracite coal combustion
Fuel oil combustion
Residual oil
¥ T*«1.t™
Utility
Industrial
Commercial
Distillate oil
Utility
Commercial
Residential
Natural gas combustion
Liquefied petroleum gas
Wood waste combustion
in boilers
Lignite combustion
Bagasse combustion
Residential fireplaces
Residential wood stoves
Waste oil combustion
Solid waste HKTKVM!
Refuse combustion
Conical burners (wood waste)
Sewage sludge incineration
Internal combustion engines
Highway vehicles
Off highway vehicles
Chemical processes
Charcoal
Hydrofluoric acid
Spar drying
Spar handling
Transfer
Paint and varnish
Phosphoric acid (thermal process)
Pthalic anhydride
Soap and detergents
Sodium carbonate
Sulfuric acid
Food and agricultural
Alfalfa dehydrating
Primary cyclone
Meal collector cyclone
Pellet cooler cyclone
Pellet regrind cyclone
Coffee roasting
Cotton ginning
Grain elevators and
processing plants
Fermentation
Meat smokehouses
Category
Number
a
a
a
a
a
. a
a
a
a
a
a
a
b
a
a
a
a
2
a '
c
1
9
3
3
3
4
a
9
a
a
b
b
7
7
7
6
b
a
6,7
9
AP-42
Section
6.8
6.10
6.10.3
6.11
614
.it
6.16
6.17
6.18
7.1
7.2
7.3
7.4
7.5
7.6
7.7
7.8
7.9
7.10
7.11
7.12
7.13
7.14
7.15
7.18
Source
Category
Ammonium nitrate fertilizers
Phosphate fertilizers
Ammonium phosphates
Reactor/ammoniator-granulator
Dryer/Moler
Starch manufacturing
Urea -
Category
Number*
a
3
4
4
7
0
Defoliation and harvesting of cotton
Trailer loading
Transport
Harvesting of grain
Harvesting machine
Truck loading
Field transport
Ammonium sulfate
Rotary dryer
Fluidized bed dryer
Metallurgical
Primary aluminum production
Bauxite grinding
Aluminum hydroxide calcining
Anode baking furnace
Prebakecell
Vertical Soderberg
Horizontal Soderberg
Coke manufacturing
Primary copper smelting
Ferroalloy production
Iron and steel production
Blastfurnace
Slips
Cast house
Sintering
Windbox
Sinter discharge
Basic oxygen furnace
Electric arc furnace
Primary lead smelting
Zinc smelting
Secondary aluminum operations
Sweating furnace
Smelting
Crucible furnace
Reverbcratory furnace
Secondary copper smelting
6
6
6
6
6
b
b
4
5
9
a
8
a
a
a
a
a
a
a
a
a
a
a
8
8
8
a
and alloying 8
Gray iron foundries a
Secondary lead Processing a
Secondary magnesium smelting 8
Steel foundries - melting b
Secondary zinc processing 8
Storage battery production b
Leadbearing ore crushing and grinding 4
Data for numbered categories are given in Table C.2-2. Particle size data on "a" categories are found in the AP-42
text; for "b" categories, in Appendix C.I; and for "c" categories, in AP-42 Volume II; Mobile Sources.
9/90
Appendix C.2
C.2-5
-------
TABLE C.2-1. PARTICLE SIZE CATEGORY BY AP-42 SECTION (cont.)
AP-42
Section
8.1
8.3
8.5
8.6
8.7
8.8
8.9
8.10
8.11
8.13
8.14
8.15
8.16
8.18
Source
Category
Category
Number*
Mineral products
Asphallic concrete plants a
Bricks and related clay products
Raw materials handling
Dryers, grinders, etc. b
Tunnel/periodic kilns
Gas fired a
Oil fired a
Coal fired a
CastaMe refractories
Raw material dryer 3
Raw material crushing and screening 3
Electric arc melting 8
Curing oven 3
Portland cement manufacturing
Dry process
Kilns a
Dryers, grinders, etc. 4
Wet process
Kilns a
Dryers, grinders, etc. 4
Ceramic clay manufacturing
Drying 3
Grinding 4
Storage 3
Clay and fly ash sintering
Fly ash sintering, crushing, screening,
yard storage 5
Clay mixed with coke
Crushing, screening, yard storage 3
Coal cleaning 3
Concrete batching 3
Glass fiber manufacturing
Unloading and conveying 3
Storage bins 3
Mixing and weighing 3
Glass furnace - wool a
Glass furnace - textile a
Glass manufacturing a
Gypsum manufacturing
Rotary ore dryer a
Roller mill 4
Impact mill 4
Flash calciner a
Continuous kettle calciner a
Lime manufacturing a
Mineral wool manufacturing
Cupola 8
Reverberatory furnace 8
Blow chamber 8
Curing oven 9
Cooler 9
Phosphate rock processing
Drying a
Calcining a
Grinding b
Transfer and storage 3
AP-42
Section
8.19.1
8.19.2
8.22
8.23
8.24
10.1
11.1
11.2
Source
Category
Category
Number*
Sand and gravel processing
Continuous drop
Transfer station
Pile formation - stacker
Batch drop
Active storage piles
Vehicle traffic on unpaved road
Crushed stone processing
Dry crushing
Primary crushing
Secondary crushing and screening
Tertiary crushing and screening
Recrushing and screening
Fines mill
Screening, conveying, handling
Taconite ore processing
Fine crushing
Pellet handling
Grate discharge
Grate feed
Bentonite blending
Coarse crushing
Ore transfer
Bentonite transfer
Unpaved roads
Metallic minerals processing
Western surface coal mining
Wood products
Chemical wood pulping
Miscellaneous sources
Wildfires and prescribed burning
Fugitive dust
a
a
3
4
4
a
4
a
4
5
4
4
3
3
4
a
*Dala for numbered categories are given in Table C.2-2. Particle size data on "a" categories are found in the AP-42
text; for "b" categories, in Appendix C.I; and for "c" categories, in AP-42 Volume II: Mobile Sources.
C.2-6
EMISSION FACTORS
9/90
-------
C\ 2.3 How To Use The Generalized Particle Size Distributions For Controlled
Processes
To calculate the size distribution and the size specific emissions for a
source with a particulate control device, the user first calculates the
uncontrolled size specific emissions. Next, the fractional control efficiency
for the control device is estimated, using Table C.2-3. The Calculation Sheet
provided (Figure C.2-2) allows the user to record the type of control device
and the collection efficiencies from Table C.2-3, the mass in the size range
before and after control, and the cumulative mass, the user will note that
the uncontrolled size data are expressed in cumulative fraction less than the
stated size. The control efficiency data apply only to the size range
indicated and are not cumulative. These data do not include results for the
greater than 10 /*m particle size range. In order to account for the total
controlled emissions, particles greater than 10 pm in size must be included.
C.2.4 Example Calculat i on
An example calculation of uncontrolled total particulate emissions,
uncontrolled size specific emissions, and controlled size specific emission is
shown on Figure C.2-1. A blank Calculation Sheet is provided in Figure C.2-2.
TABLE C.2-3
TYPICAL COLLECTION EFFICIENCIES OF VARIOUS
PARTICULATE CONTROL DEVICES3
AIRS
Code1
Particle size
Type of collector
0 - 2.5 2.5 - 6
6 - 10
001 Wet scrubber - hi-efficiency 90
002 Wet scrubber - med-efficiency 25
003 Wet scrubber - low-efficiency 20
004 Gravity collector - hi-efficiency 3.6
005 Gravity collector - med-efficiency 2.9
006 Gravity collector - low-efficiency 1.5
007 Centrifugal collector - hi-efficiency 80
008 Centrifugal collector - med-efficiency 50
009 Centrifugal collector - low-efficiency 10
010 Electrostatic precipitator -
hi-efficiency 95
Oil Electrostatic precipitator -
med-efficiency boilers 50
other 80
012 Electrostatic precipitator -
low-efficiency boilers 40
other 70
014 Mist eliminator - high velocity >250 FPM 10
015 Mist eliminator - low velocity <250 FPM 5
016 Fabric filter - high temperature 99
017 Fabric filter - med temperature 99
018 Fabric filter - low temperature 99
95
85
80
5
4
3.2
95
75
35
99
80
90
70
80
75
40
99.
99.
99.5
99
95
90
6
4.8
3.7
95
85
50
99.5
94
97
90
90
90
75
99.5
99.5
99.5
9/90
Appendix C.2
C.2-17
-------
046
049
050
051
052
053
054
055
056
057
058
059
061
062
063
064
071
075
076
077
085
086
Process change
Liquid filtration system
Packed-gas absorption column
Tray- type gas absorption column
Spray tower
Venturi scrubber
Process enclosed
Impingement plate scrubber
Dynamic separator (dry)
Dynamic separator (wet)
Mat or panel filter - mist collector
Metal fabric filter screen
Dust suppression by water sprays
Dust suppression by chemical stabilizer
or wetting agents
Gravel bed filter
Annular ring filter
Fluid bed dry scrubber
Single cyclone
Multiple cyclone w/o fly ash reinjection
Multiple cyclone w/fly ash reinjection
Wet cyclonic separator
Water curtain
--
50
90
25
20
90
1.5
25
90
50
92
10
40
40
0
80
10
10
80
50
50
10
--
75
95
85
80
95
3.2
95
95
75
94
15
65
65
5
90
20
35
95
75
75
45
--
85
99
95
90
99
3.7
99
99
85
97
20
90
90
80
97
90
50
95
85
85
90
aData represent an average of actual efficiencies. Efficiencies are
representative of well designed and well operated control equipment. Site-
specific factors (e. g., type of particulate being collected, varying pressure
drops across scrubbers, maintenance of equipment, etc.) will affect collection
efficiencies. Efficiencies shown are intended to provide guidance for
estimating control equipment performance when source-specific data are not
available. Dash - Not applicable.
Control codes in Aerometric Information Retrieval System (AIRS), formerly
National Emissions Data Systems.
C.2-18 EMISSION FACTORS 9/90
-------
References for Appendix C.2
1. Fine Particle Emission Inventory System, Office Of Research And
Development, U. S. Environmental Protection Agency, Research Triangle
Park, NC, 1985.
2. Confidential test data from various sources, PEI Associates, Inc.,
Cincinnati, OH, 1985.
3. Final Guideline Document: Control Of Sulfuric Acid Production Units.
EPA-450/2-77-019, U. S. Environmental Protection Agency, Research
Triangle Park, NC, 1977.
4. Air Pollution Emission Test. Bunge Corp.. Destrehan. LA. EMB-74-GRN-7,
U. S. Environmental Protection Agency, Research Triangle Park, NC, 1974.
5. I. W. Kirk, "Air Quality In Saw And Roller Gin Plants", Transactions Of
The ASAE. 20:5, i977.
6. Emission Test Report. Lightweight Aggregate Industry. Galite Corp.. EMB-
80-LWA-6, U. S. Environmental Protection Agency, Research Triangle Park,
NC, 1982.
7. Air Pollution Emission Test. Lightweight Aggregate Industry. Texas
Industries. Inc.. EMB-80-LWA-3, U. S. Environmental Protection Agency,
Research Triangle Park, NC, 1975.
8. Air Pollution Emission Test. Empire Mining Company. Palmer. Michigan.
EMB-76-IOB-2, U. S. Environmental Protection Agency, Research Triangle
Park, NC, 1975.
9. H. Taback, et al., Fine Particulate Emissions From Stationary Sources In
The South Coast Air Basin. KVB, Inc., Tustin, CA, 1979.
10. K. Rosbury, Generalized Particle Size Distributions For Use In Preparing
Particle Size Specific Emission Inventories. EPA Contract No. 68-02-
3890, PEI Associates, Inc., Golden, CO, 1985.
9/90 Appendix C.2 C.2-19
-------
APPENDIX D
PROCEDURES FOR SAMPLING SURFACE/BULK DUST LOADING
Procedures are herein recommended for collection of road dust and
aggregate material samples from unpaved and paved industrial roads, and from
storage piles. These recommended procedures are based on a review of American
Society Of Testing And Materials (ASTM) standards. The recommended procedures
follow ASTM standards where practical, and where not, an effort has been made
to develop procedures consistent with the intent of the majority of pertinent
ASTM Standards.
1. Unpaved Industrial Roads
The main objective in sampling the surface material from unpaved roads is
to collect composite samples from major road segments within an industrial
facility. A composite, or gross, sample comprises of several incremental
samples collected from representative subareas of the source. A road segment
can be defined as the distance between major intersections. Major road
segments can be identifed by an analysis of plant delivery, shipment and
employee travel routes and should be mapped before sampling begins.
The goal of this sampling procedure is to develop data on the mean silt
and moisture contents of surface material from a given road segment.
"Representative" samples will be collected and analyzed through the use of
compositing and splitting techniques. A composite sample is formed by the
collection and subsequent mixing of the combined mass obtained from multiple
increments or grabs of the material in question. The analyzed, or test,
sample refers to the reduced quantity of material extracted, or split, from
the larger field sample. A minimum of 0.4 kg (-1 Ib) of sample is required
for analysis of the silt fraction and moisture content.
A gross sample of 5 kg (10 Ib) to 23 kg (50 Ib) from every unpaved road
segment should be collected in a clean, labeled, 19 liter (5 gal) plastic pail
with a scalable poly liner. This sample should be composited from a minimum
of three incremental samples, but it may consist of only one, depending on the
length of the road segment and hazards to the sampling team. The first sample
increment is collected at a random location within the first 0.8 km (0.5 mi)
of the road segment, with additional samples collected from each remaining 0.8
km (0.5 mi) of the road segment up to a maximum road segment length of 4.8 km
(3 mi).
An acceptable method of selecting three sample locations on road segments
of less than 1.5 mi length is to sample at locations represented by three
random numbers (x^, X2> X3), between 0.0 mi and y mi, the road segment length.
A scientific handheld calculator can produce pseudorandom numbers, or they may
be obtained from statistical tables.
9/90 Appendix D D-l
-------
o
Ni
Road
Intersection
Road Length £1.5 mi
1ft.
1ft.
1ft.
0.5mi ^- -* 0.5mi *~ ~+ 0.5mi—
n
3
CO
t— I
§
ss
o
8
JO
CA
Road
Intersection
Road Length <1.5 mi
1 ft.
1 ft. 1 ft.
x2-
Road
Intersection
VO
O
Figure 1. Recommended Sampling Locations for an Industrial Unpaved Road
-------
Date Sample Collected.
Sampling Data for
Unpaved Roads
Recorded by.
Type of Material Sampled:
Site of Sampling*:
SAMPLING METHOD
1. Sampling device: whisk broom and dust pan
2. Sampling depth: loose surface material (do not abrade road base)
3. Sample container: metal or plastic bucket with sealed poly liner
4. Gross sample specifications:
(a) 1 sample of 23kg (50 Ib) minimum for every 4.8 km (3 mi) sampled
(b) composite of at least 3 increments: lateral strips of 30 cm (1 ft) width extending over
traveled portion of roadway
Indicate deviations from above methods and general meteorology:
SAMPLING DATA
Sample
No.
Time
Location*
Surface
Area
Depth
Quantity
of Sample
Use code given on plant or road map for segment identification and indicate sample
on map.
Figure 2. Data Form For Unpaved Road Sampling.
9/90
Appendix D
D-3
-------
Figure 1 illustrates sampling locations along industrial unpaved roads.
The width of each sampled area across the road should be 0.3 m (1 ft). Only
the travelled section of the roadway should be sampled.
The loose surface material is removed from the hard road base with a
whisk broom and dustpan. The material should be swept carefully to prevent
injection of fine dust into the atmosphere. The hard road base below the
loose surface material should not be abraded so as to generate more fine mate-
rial than exists on the road in its natural state. Figure 2 is a data form to
be used for the sampling of unpaved roads.
2 . Payed Industrial Roads
For paved roads, it is necessary to obtain a representative sample of
loading (mass/area) from the travelled surface to characterize particulate
emissions caused by vehicle traffic. A composite sample should be collected
from each major road 'segment in the plant. A minimum sample mass of 0.4 kg
(~1 Ib) should be composited from a minimum of three separate increments.
Figure 3 is a diagram showing the locations of incremental samples for a
two-lane paved industrial road. The first sample increment should be
collected at a random location between 0.0 and 0.8 km (0.5 mi). Additional
samples should be collected from each remaining 0.8 km (0.5 mi) of the road
segment, up to a maximum road segment length of 8 km (5 mi). For road
segments of less than 2.4 km (1.5 mi) in length, an acceptable method would be
to collect sample increments at three randomly chosen locations (x^, ^> X3)>
between 0.0 km and y km, the road length.
Care must be taken that sampled dust loadings are typical of only the
travelled portion of the road segment of interest. On paved roads painted
with standard markings, the area from "solid white line to solid white line"
should be sampled. Curbs should not be sampled, since vehicles are not likely
to disturb dust from this area.
Each incremental sample location consists of a lateral strip from 0.3 to
3 m (1 to 10 ft) wide across the travelled portion of the roadway. The exact
area to be sampled depends on the amount of loose surface material on the
paved roadway. For a visibly dirty road, a width of 0.3 m (1 ft) is
sufficient, but for a visibly clean road, a width of 3 m (10 ft) could be
required to obtain an adequate sample.
This sampling procedure is the preferred method of collecting surface
dust from a paved industrial road segment. However, if for lack of resources
or traffic hazards collection of a minimum of three sample increments across
all travel lanes is not feasible on a short road segment (<2.4 km or 1.5 mi),
sampling from a single representative paved strip 3 to 9 m (10 to 30 ft) wide
across each lane will likely produce sufficient sample for analysis.
Samples are removed from the road surface by vacuuming, preceded by broom
sweeping if large aggregate is present. The sample number is identified and
the sampled area measured and is recorded on the appropriate data form. With
a whisk broom and a dust pan, the larger particles are collected from the
sampling area and placed in a clean, labeled plastic jar. The remaining
t
D-4 EMISSION FACTORS 9/90
-------
VO
O
Road
Intersection
Road Length >1.5 mi
1-10 ft.
1-10 ft.
0.5 mi-
0.5 mi
1-10 ft.
0.5 mi
•o
(D
H-
X
Road
Intersection
Road Length <1.5 mi
J v :
1-10 ft.
x2-
1-10 ft. 1-10 ft.
Road
Intersection
90-13 GREL grel schemZ II 042790
G
Figure 3. Recommended Sampling Locations for an Industrial Paved Road
-------
Paved Road Loading
Date Sample Collected.
Recorded by.
Type of Material Sampled:
Sampling Location*:
. No. of Traffic Lanes:
. Surface Condition:
*Use code given on plant or road map for segment identification and indicate sample on map.
SAMPLING METHOD
1. Sampling device: portable vacuum cleaner (broom sweep first if loading is heavy)
2. Sampling depth: loose surface material
3. Sample container: tared and numbered vacuum cleaner bags
4. Gross sample specifications:
(a) 1 sample every 8 km (5 mi) of road length
(b) lateral sampling strips of 30 cm (1 ft) minimum width extending from curb to curb
traveled portion of roadway
(c) do not sample curb areas
Indicate deviations from above method:
SAMPLING DATA
Sample
No.
Vac
Bag
Time
Surface
Area
Broom
Swept?
Sample
No.
Vac
Bag
Time
Surface
Area
Broom
Swept?
DIAGRAM (mark each segment with vacuum bag number)
Figure 4. Data Form For Paved Road Sampling.
D-6
EMISSION FACTORS
9/90
-------
Date Sample Collected.
Sampling Data for
Storage Piles
Recorded by
Type of Material Sampled:
Site of Sampling :
SAMPLING METHOD
1. Sampling device: pointed shovel
2. Sampling depth: 10-15 cm (4-6 in)
3. Sample container: metal or plastic bucket with sealed poly liner
4. Gross sample specifications:
(a) 1 sample of 23kg (50 Ib) minimum for every pile sampled
(b) composite of 10 increments
5. Minimum portion of stored material (at one site) to be sampled: 25%
Indicate deviations from above method (e.g., use of sampling tube for inactive piles):
SAMPLING DATA
Sample
No.
Time
Location (Refer to map)
Surface
Area
Depth
Quantity
of Sample
Figure 5. Data Form For Storage Pile Sampling.
9/90
Appendix D
D-7
-------
smaller particles are then swept from the road with an electric broom-type
vacuum sweeper. The sweeper must be equipped with an empty weighed, labeled,
disposable vacuum bag. Care must be taken to avoid tearing the bag and losing
the sample. After the sample has been collected, the bag should be removed
from the sweeper, checked for leaks and stored in a previously labeled sealed
plastic bag or paper envelope for transport. Figure 4 presents a data form to
be used for the sampling of paved roads.
3. Storage Piles
Ideally, a gross sample made up of top, middle, and bottom incremental
samples from a pile should be obtained to determine representative silt and
moisture content for use in predicting particulate emissions from wind erosion
and materials handling operations. However, it is impractical to climb to
the top or even the middle of most industrial storage piles, because of their
large size.
The most practical approach to minimize sampling location bias for large
piles is to sample as near to the middle of the pile as practical and to
select sampling locations in a random fashion. A minimum of ten incremental
samples should be obtained at locations along the entire perimeter of a large
pile. If a small pile is sampled, two sets of three incremental samples
should be collected from the pile top-, middle, and bottom. A gross sample of
5 kg (10 Ib) to 23 kg (50 Ib) from a storage pile should be placed in a clean,
labeled, 19 liter (5 gal) plastic pail with a sealable poly liner.
For determination of wind erosion estimation parameters, incremental
samples are collected by skimming the surface of the pile in an upwards
direction, using a straight-point shovel or small garden spade. Every effort
must be made not to avoid sampling larger pieces of aggregate material.
To characterize a pile for particulate emissions from materials handling
processes, incremental samples should be taken from the portion of the storage
pile surface (1) which has been been recently formed by the addition of aggre-
gate material, or (2) from which aggregate material is being reclaimed.
Samples should be collected with a shovel to a depth of 10 to 15 cm (4 to 6
in), taking care not to avoid sampling larger pieces of material.
If an inactive pile is to be sampled before loadout operations, sample
increments should be obtained using a sampling tube approximately 2 m (6 ft)
long pushed to a depth of 1 m (3 ft). The diameter of the sampling tube
should be a minimum of 10 times the diameter of the largest particle sampled.
Samples should be representative of the interior portions of the pile that
constitute the bulk of the material to be transferred. Figure 5 presents a
data form to be used for the sampling of storage piles.
D-8 EMISSION FACTORS 9/90
-------
APPENDIX E
PROCEDURES FOR LABORATORY ANALYSIS OF SURFACE/BULK DUST LOADING SAMPLES
1.0 Samples From Sources Other Than Paved Roads
1.1 Sample Preparation
Once the gross sample is brought to the laboratory, it must be prepared
for analyses of moisture and silt, the two physical parameters of principal
interest. The latter is defined as the percent of test sample mass passing a
200 mesh screen (<75 micrometers physical diameter) based on mechanical
sieving of oven-dried material. These analyses entail dividing the sample to
a workable size.
The gross sample can be divided by using (1) mechanical devices,
(2) alternative shovel method, (3) riffle, or (4) coning and quartering
method. Mechanical division devices are not discussed in this section since
they are not found in many laboratories. The alternative shovel method is
actually only necessary for samples weighing hundreds of pounds. Therefore,
only the use of the riffle and the coning and quartering method are discussed.
American Society For Testing And Materials (ASTM) standards describe the
selection of the correct riffle size and the correct use of the riffle.
Riffle slot widths should be at least three times the size of the largest
aggregate in the material being divided. Figure 1 shows two riffles for
sample division. The following describes the use of the riffle.
Divide the gross sample by using a riffle. Riffles properly used
will reduce sample variability but cannot eliminate it. Riffles are
shown in Figure 1, (a) and (b). Pass the material through the riffle
from a feed scoop, feed bucket, or riffle pan having a lip or opening
the full length of the riffle. When using any of the above containers
to feed the riffle, spread the material evenly in the container, raise
the container, and hold it with its front edge resting on top of the
feed chute, then slowly tilt it so that the material flows in a uniform
stream through the hopper straight down over the center of the riffle
into all the slots, thence into the riffle pans, one-half of the sample
being collected in a pan. Under no circumstances shovel the sample into
the riffle, or dribble into the riffle from a small-mouthed container.
Do not allow the material to build up in or above the riffle slots. If
it does not flow freely through the slots, shake or vibrate the riffle
to facilitate even flow.
The procedure for coning and quartering is best illustrated in Figure 2.
Coning and quartering is a simple procedure which is applicable to all
powdered materials and to sample sizes ranging from a few grams to several
hundred pounds.^ Oversized material, defined as >0.6 mm (3/8 in) in diameter,
should be removed prior to quartering and weighed in a tared container. The
following steps describe the procedure.
9/90 Appendix E E-l
-------
1. Mix the material and shovel it into a neat cone;
2. Flatten the cone by pressing the top without further mixing;
3. Divide the flat circular pile into equal quarters by cutting or
scraping out two diameters at right angles;
4. Discard two opposite quarters;
5. Thoroughly mix the two remaining quarters, shovel them into a cone,
and repeat the quartering and discarding procedures until the
sample has been reduced to 0.4 to 1.8 kg (1 to 4 Ib).
Preferably, the coning and quartering operation should be conducted on a floor
covered with clean 10 mil plastic. Samples likely to be affected by moisture
or drying must be handled rapidly, preferably in an area with a controlled
atmosphere, and sealed in a container to prevent further changes during
transportation and storage. Care must be taken that the material is not
contaminated by anything on the floor or that a portion is not lost through
cracks or holes.
The size of the laboratory sample is important. Too little sample will
not be representative and too much sample will be unwieldly. Ideally, one
would like to analyze the entire gross sample in batches, but this is not
practical. While all ASTM standards acknowledge this impracticality, they
disagree on the exact size, as indicated by the range of recommended samples,
extending from 0.05 to 27 kg (0.1 to 60 Ib).
The main principle in sizing the laboratory sample is to have sufficient
coarse and fine portions to be representative of the material and to allow
sufficient mass on each sieve so that the weighing is accurate. A laboratory
sample of 400 to 1600 g is recommended since these masses can be handled by
the scales normally available (1.6 to 2.6 kg capacities). Also, more sample
than this can produce screen blinding for the 20 cm (8 in) diameter screens
normally available. In addition, the sample mass should be such that it can
be spread out in a reasonably sized drying pan to a depth of < 2.5 cm (1 in).
1.2 Laboratory Analysis Of Samples For Moisture And Silt Contents
The basic recommended procedure for silt analysis is mechanical, dry
sieving after moisture analysis. Step-by-step procedures are given in
Tables 1 and 2. The moisture content is obtained from a differential weight
analysis of the bulk material before and after drying.
Non-organic samples should be oven dried overnight at 110° C (230°F)
before sieving. The sieving time is variable; sieving should be conducted for
several periods of equal interval (e. g., 10 rain), and continued until the net
sample weight collected in the pan increases by less than 3.0 percent of the
previous silt weight. A small variation of 3.0 percent is allowed since some
sample grinding due to interparticle abrasion will occur, and consequently,
the weight will continue to increase.
When the silt mass change reduces to not more than 3.0 percent, it is
thought that the natural silt has been passed through the No. 200 sieve screen
and that any additional increase is due to grinding. The sample preparation
E-2 . EMISSION FACTORS 9/90
-------
Feed Chute
SAMPLE DIVIDERS (RIFFLES)
Rolled
Edges
Riffle Sampler
(b)
Riffle Bucket and
Separate Feed Chute Stand
(b)
Figure 1. Sample Dividers (Riffles)
CONING AND QUARTERING
9/90
Figure 2. Procedure For Coning And Quartering.
Appendix E
E-3
-------
MOISTURE ANALYSIS
Date: By:
Sample No: Oven Temperature:
Material: Date In Date Out
Time In Time Out
Split Sample Balance: Drying Time
Make
Capacity Material Weight (after drying)
Smallest Division '_ Pan + Material:
Pan:
Total Sample Weight: Dry Sample: '
(Excl. Container)
Number of Splits: ' MOISTURE CONTENT:
(A) Wet Sample Wt.
Split Sample Weight (before drying) (B) Dry Sample Wt.
Pan + Sample: s (C) Difference Wt.
Pan: c x 100
Wet Sample: . A
-------
mb + mv
L =
P
(1)
where: m^ = mass of the broom swept dust (kg)
mv = mass of the vacuum swept dust (kg)
P = width of the sampling strip as measured along the
centerline of the road segment (km)
TABLE E-l. MOISTURE ANALYSIS PROCEDURE
1. Preheat the oven to approximately 110°C (230°F). Record oven
temperature.
2. Tare the laboratory sample containers which will be placed in the oven.
Tare the containers with the lids on if they have lids. Record the tare
weight(s). Check zero before each weighing.
3. Record the make, capacity, and smallest division of the scale.
4. Weigh the laboratory sample(s) in the container(s).a Record the
combined weight(s). Check zero before each weighing.
5. Place sample in oven and dry overnight.
6. Remove sample container from oven and (a) weigh immediately if
uncovered, being careful of the hot container; or (b) place tight-
fitting lid on the container and let cool before weighing. Record the
combined sample and container weight(s). Check zero reading on the
balance before weighing.
7. Calculate the moisture as the initial weight of the sample and container
minus the oven-dried weight of the sample and container divided by the
initial weight of the sample alone. Record the value.
8. Calculate the sample weight to be used in the silt analysis as the oven-
dried weight of the sample and container minus the weight of the
container. Record the value.
aFor materials with high moisture content, agitate the sample container to
ensure that any standing moisture is included in the laboratory sample
container.
"Materials composed of hydrated minerals or organic material like coal and
certain soils should be dried for only 1.5 h.
9/90 Appendix E E-5
-------
Date
Sample No:
Material:
Split Sample Balanc
Make
Capacity
Smallest Division
SILT ANALYSIS
Bv
Material Weight (after dryinq)
Pan + Material:
Pan:
e: Dry Sample:
Final Weiaht:
„,«.,. Net weiant
-------
TABLE E-2. SILT ANALYSIS PROCEDURES
1. Select the appropriate 8-in diameter, 2-in deep sieve sizes. Recommended
U.S. Standard Series sizes are: 3/8 in, No. 4, No. 20, No. 40, No. 100,
No. 140, No. 200, and a pan. Comparable Tyler Series sizes can also be
utilized. The No. 20 and the No. 200 are mandatory. The others can be
varied if the recommended sieves are not available or if buildup on one
particulate sieve during sieving indicates that an intermediate sieve
should be inserted.
2. Obtain a mechanical sieving device such as vibratory shaker or a Roto-Tap
(without the tapping function).
3. Clean the sieves with compressed air and/or a soft brush. Material
lodged in the sieve openings or adhering to the sides of the sieve should
be removed (if possible) without handling the screen roughly.
4. Obtain a scale (capacity of at least 1600 g) and record make, capacity,
smallest division, date of last calibration, and accuracy.
5. Tare sieves and pan. Check the zero before every weighing. Record
weights.
6. After nesting the sieves in decreasing order with pan at the bottom, dump
dried laboratory sample (probably immediately after moisture analysis)
into the top sieve. The sample should weigh between 400 and 1600 g (-
0.9 to 3.5 lb)a. Brush fine material adhering to the sides of the con-
tainer into the top sieve and cover the top sieve with a special lid
normally purchased with the pan.
7. Place nested sieves into the mechanical device and sieve for 10 min.
Remove pan containing minus No. 200 and weigh. Repeat the sieving in 10-
min intervals until the difference between two successive pan sample
weighings (where the tare of the pan has been subtracted) is less than
3.0 percent. Do not sieve longer than 40 min.
8. Weigh each sieve and its contents and record the weight. Check the zero
reading on the balance before every weighing.
9. Collect the laboratory sample and place the sample in a separate
container if further analysis is expected.
10. Calculate the percent of mass less than the 200 mesh screen (75 urn).
This is the silt content.
aThis amount will vary for finely textured materials; 100 to 300 g may be
sufficient when 90% of the sample passes a No. 8 (2.36 mm) sieve.
2.2 Sample Preparation And Analysis For Road Dust Silt Content
After weighing the sample to calculate total surface dust loading on the
traveled lanes, the broom swept particles and vacuum swept dust are
9/90 Appendix E E-7
-------
composited. The composited sample is usually small and may require no sample
splitting in preparation for sieving. If splitting is necessary to prepare a
laboratory sample of 400 to 1600 g, the techniques discussed in Section 1.1
can be used. The laboratory sample is then sieved using the techniques
described in part 1.2 above.
References For Appendix E
1. "Standard Method Of Preparing Coal Samples For Analysis", D2013-72,
Annual Book Of ASTM Standards. 1977.
2. L. Silverman, et al.. Particle Size Analysis In Industrial Hygiene.
Academic Press, New York, 1971.
PRIOTBC OFFICE 1990/727-090/27002
E-8 EMISSION FACTORS 9/90
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TECHNICAL REPORT DATA
(Please read Instructions on the reverse before completing}
REPORT NO.
AP-42 Supplement C
2.
3. RECIPIENT'S ACCESSION NO.
*. TITLE AND SUBTITLE
Supplement C to Compilation Of Air Pollutant Emission
Factors. AP-42, Fourth Edition
5. REPORT DATE
September 1990
6. PERFORMING ORGANIZATION CODE
1. AUTHOR(S)
8. PERFORMING ORGANIZATION REPORT NO.
i
). PERFORMING ORGANIZATION NAME AND ADDRESS
U. S. Environmental Protection Agency
Office Of Air And Radiation
Office Of Air Quality Planning And Standards
Research Triangle Park, NC 27711
10. PROGRAM ELEMENT NO.
11. CONTRACT/GRANT NO.
12. SPONSORING AGENCY NAME AND ADDRESS
13. TYPE OF REPORT AND PERIOD COVERED
14. SPONSORING AGENCY CODE
15. SUPPLEMENTARY NOTES
EPA Editor: Whitmel M. Joyner
16. ABSTRACT
In this Supplement to the Fourth Edition of AP-42, new or revised emissions data
are presented for Residential Wood Stoves; Refuse Combustion; Sewage Sludge
Incineration; Magnetic Tape Manufacturing Industry; Surface Coating Of Plastic Parts
For Business Machines; Synthetic Fiber Manufacturing; Primary Lead Smelting; Gray
Iron Foundries; Chemical Wood Pulping; Willdfires And Prescribed Burning; Industrial
Paved Roads; Industrial Wind Erosion; Explosives Detonation; Appendix C.2,
"Generalized Particle Size Distributions"; Appendix D, "Procedures For Sampling
Surface/Bulk Dust Loading1!; and Appendix E, "Procedures For Laboratory Analysis Of
Surface/Bulk Dust Loading Samples".
17.
KEY WORDS AND DOCUMENT ANALYSIS
DESCRIPTORS
b.lDENTIFIERS/OPEN ENDED TERMS C. COS AT I Field/Group
Stationary Sources
Point Sources
Area Sources
Emission Factors
Emissions
18. DISTRIBUTION STATEMENT
19. SECURITY CLASS .(Tins Report)
, NO. OF PAGES
170
20. SECURITY CLASS (Thispage)
22. PRICE
EPA Form 2220-1 (Rev. 4-77) PREVIOUS EDITION is OBSOLETE
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