PB-206 924
AIR POLLUTANT EMISSION FACTORS
TRW Systems Group
McLean, Virginia
April 1970
NATIONAL TECHNICAL INFORMATION SERVICE
Distributed ,., 'to foster, serve
and promote the nation's
economic development
and technological
advancement.'
U.S. DEPARTMENT OF COMMERCE
This document has been approved for public release and sale.
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BIBLIOGRAPHIC DATA
SHEET
1. RepuU No.
APTD-0923
3. Recipient's Accession No.
4. Title an<^ Subtitle
Air Pollutant Emission Factors
5. Report Date
April 1970
6.
7. Author(s)
8* Performing Organization Rept.
No> 13799.000
9. Performing Organization Name and Address
TRW
Systems Group of TRW, Inc.
10. Project/Task/Work Unit No.
11. Contract /i£tonc No.
CPA 22-69-119
12. Sponsoring Organization Name and Address
Department of Health, Education, and Welfare
Public Health Service
National Air Pollution Control Administration
Washington, D. C.
13. Type of Report & Period
Covered
14.
15. Supplementary Notes.
16. Abstracts Atmospheric emission data is compiled for a wide variety of selected
One-half of the 40 processes discussed involve an updating or review of existing emission
factors. Except for the combustion and incineration fields, very little new emission fac
tor data has been made public since 1967. Frequently, material balance calculations were
made. Detailed information is generally appended to each section. Whenever possible, the
range or variation in emission factors is reported. All emission factors were ranked
according to the available data upon which they were based. The range of values for man>
emission factors is large. The factors are presented in these major section's: Stationary
Fuel Combustion; Refuse Disposal; Chemical Manufacturing Industries; Food and Agricul-
tural Industry; Metallurgical Industries; Mineral Products Industry; and Organic Solvents
L7. Key Words and Document
Air pollution
Sxhaust emissions
Fuels
Solid waste disposal
Chemical plants
Food industry
Metal industry
Minerals
Rocks
Mining
Fly ash
Sintering
Concretes
Dry cleaning
Solvents
Coal
17b. Identifiers/Open-Ended Terms
Analysis. 17a. Descriptors
Combustion.products
Hydrocarbons
Fuel oil
Steam electric power generation
Wood
Boilers
Combustion
Lead (metal)
Magnesium
Zinc
Clays
Ceramics
Bricks
Refractories
Ammonia
Asphalts
Carbon black
Charcoal
Hydrofluoric acid
Paints
Varnishes
Plastics
Printing
Detergents
Soaps
Synthetic elastomers
Grain processing
Coke
Steel
17c. COSATI Field/Group 13B
18. Availability Statement
Unlimited
19..Security Class (This
Report)
UNCLASSIFIED
20. Security Class (This
Page
UNCLASSIFIED
21, No. of Pages
338
22. Price
FORM NTIS-JB (10-701
USCOMM-DC 40329-f7l
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13799.000
AIR POLLUTANT
EMISSION FACTORS
April 1970
Prepared for
Department of Health, Education and Welfare
Public Health Service
Environmental Health Service
National Air Pollution Control Administration
Washington, D. C.
TRW
gmrna MM* of nw me.
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11
This report contains an updating of selected existing
emission factors in addition to twenty new factors compiled for
the National Air Pollution Control Administration, Division of
Air Quality and Emission Data, under contract CPA-22-69-119.
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TABLE OF CONTENTS
1. INTRODUCTION 1-1
2. STATIONARY FUEL COMBUSTION 2-1
t t
2.1 Anthracite Coal Combustion 2-2
Appendix 2.1 2-9
References 2.1 2-18
2.2 Bituminous Coal Combustion - Gaseous Emissions 2-20
Appendix 2.2 2-26
References 2.2 2-30
2.3 Hydrocarbon Emissions from Fuel Oil Combustion
in Power Plants 2-33
Appendix 2.3 2-36
References2-3 2-37
2.4 Liquefied Petroleum Gas Combustion 2-39
Appendix 2.4 2-43
References 2.4 2-46
2.5 Wood Waste Combustion in Boilers 2-47
Appendix 2.5 2-51
References 2.5 2-54
3. REFUSE DISPOSAL; . 3-1
3.1 Refuse Incineration 3-2
Appendix 3.1 3-10
References 3.1 3-15
3.2 Automobile Body Incineration 3-17
Appendix 3.2 3-20
References1^.2%..;,,<,,. ::.,,. 3-22
3.3 Municipal Refuse and"W6bd''Dispbsal in Conical
Burners 3-23
Appendix 3.3 3-26
References 3.3 3-30
3.4 Open Burning 3-32
Appendix 3.4 3-35
References 3.4 3-39
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IV
TABLE OF'CONTENTS (continued)
4. "'CHEMICAL MANUFACTURING INDUSTRIES; 4-1
4.1 Ammonia \ 4-2
Appendix 4.1 , 4-6
References 4.1 \ 4-7.
4.2 Asphalt Roofing \ 4-8
Appendix 4.2 ', 4-12
References 4.2 ', 4-15
4.3 Carbon Black \ 4-16
Appendix 4.3 4-22
References 4.3 ' 4-29
4.4 Charcoal . 4-30
Appendix 4.4 4-36
References 4.4 4-38
4.5 Hydrofluoric Acid 4-39
References 4.5 4-42
4.6 Paint and Varnish 4-43
Appendix 4.6 4-47
References 4.6 4-48
4.7 Plastics 4-5£
References 4.7 4-56
4.8 Printing Ink 4-57
References 4.8 4-62
4.9 Soap and Detergents 4-63
Appendix 4.9 4-6,8
References 4.9 4-70
4.10 Synthetic Rubber 4-71
References 4.10 4-75
4.11 Synthetic Fibers 4-76
References 4.11 4-83
5. FOOD AND AGRICULTURAL INDUSTRY^ 5-1.
5.1 Feed and Grain Mills and Elevators 5-2
Appendix 5.1 5-7
References 5.1 5-8-
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TABLE OF CONTENTS (continued)
5.2 Meat Smokehouses 5-9
Appendix 5.2 5-13
References 5.2 5-15
5.3 Fermentation 5-16
References 5.3 5-23
^"vs
6/ METALLURGICAL INDUSTRIES; 6-1
6.1 Metallurgical Coke Manufacture 6-2
Appendix 6.1 6-7
References 6.1 6-9
6.2 Steel Foundries 6-10
Appendix 6.2 6-16
References 6.2 6-18
6.3 Secondary Lead Smelting 6-21
Appendix 6.3 6-26
References 6.3 6-28
6.4 Secondary Magnesium Smelting 6-29
Appendix 6.4 6-31
References 6.4 6-32
6.5 Secondary Zinc Processing . 6-33
Appendix 6.5 6-37
References 6.5 6-38
7. MINERAL PRODUCTS INDUSTRY; 7-1
7.1 Ceramic Clay Manufacturing 7-2
Appendix 7.1 7-7
References 7.1 7-11
7.2 Bricks and Related Clay Products Manufacturing 7-12
Appendix 7.2 " 7-16
References 7.2 7-17
7.3 Castable Refractories Manufacturing 7-18
Appendix 7.3 -: . 7-21
References 7.3 7-22
7.4 Stone Quarrying and Processing 7-23
References 7.4 7-28
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TABLE OF CONTENTS (continued)
7.5 Gypsum Manufacturing 7-29
References 7.5 7-33
7.6 Clay and Fly Ash Sintering 7-34
Appendix 7.6 7-41
References 7.6 7-43
7.7 Lime Manufacturing 7-44
Appendix 7.7 7-49
References 7.7 7-50
7.8 Concrete Batching 7-51
References 7.8 7-53
7.9 Fiber Glass Manufacturing 7-54
Appendix 7.9 7-59
References 7.9 7-60
7.TO Pulpboard Manufacturing 7-61
References 7.10 7-65
ORGANIC SOLVENTS ..,. 8-1
8.1 Dry Cleaning ' 8-2
Appendix 8.1 8-;6
References 8.1 ' .. 8-7
8.2 Surface Coating 8-^8
Appendix 8.2 -8-10
References 8.2 8-11
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vn
LIST OF TABLES
Table No. Page
2.1-1 Anthracite Coal Characteristics 2-2
2.1-2 Uncontrolled Emissions from Anthracite
Coal Combustion 2-5
2.1-3 Ranking of Anthracite Coal Combustion Emission
Factors 2-7
2.1-4 Anthracite Coal Emission Data 2-12
2.1-5 Average Particulate Emission From Anthracite
Coal Combustion in Traveling Grate Stokers 2-10
2.1-6 Hydrocarbon Emission Factors 2-16
2.2-1 Selected Gaseous Emissions from Bituminous Coal
Combustion 2-22
2.2-2 Gaseous Emission Factor Ranking for Bituminous
Coal 2-25
2.3-1 Emission Factor Ranking for Hydrocarbons 2-35
2.4-1 Emissions from LPG Combustion, pounds per
1000 gallons 2-41
2.4-2 LPG Emission Factor Ranking 2-42
2.4-3 Properties of LPG 2-43
2.4-4 Emission Factors for Natural Gas Combustion 2-44
2.5-1 Emission Factors for Wood and Bark Combustion
in Boilers, Ib/ton of fuel-fired 2-49
2.5-2 Emission Factor Ranking for Wood Combustion
in Boilers 2-50
2.5-3 Ultimate Analysis of Wood Refuse Burned, percent
by weight 2-52
2.5-4 Ultimate Analysis of Wood and Bark, percent by
weight 2-52
2.5-5 Comparable Emission Data for Wood, Bark, and
Coal Combustion 2-53
3.1-1 Emission Factors for Refuse Incineration 3-5
3.1-2 Particulate Control Efficiencies of Various
Types of Control Equipment Applied to
Municipal Incinerators 3-6
3.1-3 Chemical Analysis of Fly Ash Samples from
Typical Municipal Incinerator 3-6
3.1-4 Emission Factor Ranking for Incinerators 3-9
3.1-5 Emissions from Municipal Multiple Chamber
Incinerators, Ibs/ton of Refuse Charged 3-10
3.1-6 Emissions from Industrial and Commercial Multiple
Chamber Incinerators, Ibs/ton of Refuse Charged 3-11
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VI11
LIST OF TABLES (continued)
3.1-7 Emissions from Industrial and Commercial Single
Chamber Incinerators, Ibs/ton of Refuse Charged 3-11
3.1-8 Emissions from Flue Fed Incinerators, Ibs/ton of
Refuse Charged 3-12
3.1-9 Emissions from Modified Flue Fed Incinerators,
Ibs/ton of Refuse Charged 3-13
3.1-10 Emissions from Domestic Incinerators (Without
Gas-Fired Primary Burner) Ibs/ton of Refuse
Charged 3-13
3.1-11 Emissions from Domestic Incinerators (With Gas
Afterburner), Ibs/ton of Refuse Charged 3-14
3.1-12 Emissions from Pathological Incinerators,
Ibs/ton of Refuse Charged 3-14'
3.2-1 Emissions from Automobile Body Incineration,
Ibs/Car Burned 3-18
3.2-2 Automobile Body Incineration Emission Ranking 3-19
3.3-1 Emission Factors for Waste Incineration in
Conical and Cylindrical Burners 3-24
3.3-2 Emission Factor Ranking for Conical Burners 3-25
3.3-3 Particulate Emissions from a Pilot Scale
Concial Burner 3-26
3.3^4 Gaseous Emissions from Municipal Waste Incineration 3-27
3.3-5 Emissions from Wood Waste Incineration 3-28
3.4-1 Emission Factors for Open Burning 3-33
3.4-2 Emission Factor Ranking for Open Burning 3-34
3.4-3 Emissions from Open Burning of Municipal Refuse 3-37
3.4-4 Emissions from Open Burning of Automobile Components 3-37
3.4-5 Emissions from Open Burning of Horticultural Refuse 3-38
4.1-1 Uncontrolled Emissions from Ammonia Manufacturing,
Ibs/ton 4-5 .
4.1-2 Ammonia Emission Factor Ranking 4-5
4.2-1 Emission Factors for Asphalt Roofing 4-10
4.2-2 Emission Factor Ranking for Asphalt Roofing 4-11
4.2-3 Test Data from Asphalt Blowing Operation 4-l:2
4.2-4 Emissions from Asphalt Blowing Operation,
Ibs/ton of input 4-12
4.2-5 Reported Uncontrolled Particulate 'Emissions from
Felt Saturation 4-13
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IX
LIST OF TABLES (continued)
4.3-1 Emissions from Carbon Black Manufacturing Processes 4-20
4.3-2 Carbon Black Emission Factor Ranking 4-21
4.4-1 Products from Hardwood Distillation, percent
by weight 4-31
4.4-2 Emission Factors for the Manufacture of Charcoal
Ibs/ton of product 4-34
4.4-3 Emission Factor Ranking for Charcoal Manufacturing 4-34
4.4-4 Gaseous Constituents of Wood, Percent by Volume 4-36
4.4-5 Gaseous Constituents of Wood, Percent by Weight 4-37
4.5-1 Emissions from Hydrofluoric Acid Manufacturing
Ibs/ton 4-41
4.5-2 Emission Factor Ranking for Hydrofluoric Acid 4-41
4.6-1 Typical Varnish Raw Materials and Emissions
During Cooking 4-44
4.6-2 Uncontrolled Emission Factors for Paint and
Varnish Manufacturing 4-45
4.6-3 Emission Factor Ranking for Paint and Varnish
Manufacture 4-46
4.7-1 Plastic Manufacturing Emissions and Sources 4-53
4.7-2 Estimated Emissions from Plastics Manufacturing
Ibs/ton 4-54
4.7-3 Emissions Factor Ranking 4-55
4.8-1 Typical Ink Formulas 4-59
4.8-2 Emissions from Printing Ink Manufacturing 4-61
4.8-3 Emission Factor Ranking for Printing Ink
Manufacture 4-61
4.9-1 Particulate Emissions from Detergent Spray Drying 4-65
4.9-2 Detergent Manufacturing Emission Factor Ranking 4-67
4.10-1 Emissions from Synthetic Rubber Plant 4-73
4.10-2 Emission Factor Ranking 4-74
4.11-1 Types of Fibers and Films 4-77
4.11-2 Emission Factors for Synthetic Fiber Manufacturing 4-81
4.11-3 Emission Factor Ranking for Synthetic Fibers 4-82
5.1-1 Size of Particulate Matter Generated from Dust
Conveyor System 5-5
5.1-2 Particulate Emissions from Grain Handling and
Processing 5-5
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LIST OF TABLES (continued)
5.1-3 Emission Factor Ranking for Grain Handling and
Processing 5-6
5.2-1 Emissions from Meat Smoking, Ibs/ton of Meat 5-11
5.2-2 Emission Factor Ranking 5-12
5.2-3 Wood Smoke Emissions 5-13
5.3-1 Fermentation Products 5-16
6.1-1 Recovered Coking By-Products 6-5
6.1-2 Emission Factors for By-Product Coking, Ibs/ton
of Coal Charged 6-6
6.6-3 Emission Factor Ranking for Metallurgical Coke 6-5
6.1-4 Coke Plant Emission Data 6-7
6.1-5 Polish Estimates of Coke Plant Emissions 6-8
6.2-1 Typical Particle Size Distribution 6-13
6.2-2 Foundry Operations Emissions
6.2-3 Emission Factors for Steel Foundries 6-14
6.2-4 Steel Foundry Emission Factor Ranking 6-15
6.3-1 Lead Smelting Emissions, Ibs/ton Processes 6-24
6.3-2 Emission Factor Ranking 6-25
6.4-1 Magnesium Smelting Emissions 6-30
6.5-1 Emissions from Zinc Smelting 6-35
6.5-2 Emission Factor Ranking 6-36
7.1-1 Emission Factors for Ceramic Clay Manufacture 7-5
7.1-2 Emission Factor Ranking for Ceramic Clay
Manufacture 7-6
7.1-3 Clay Dryer Particulate Emissions Test Data 7-7
7.1-4 Estimated Uncontrolled Particulate Emissions
from the Clay Drying Process 7-8-
7.2-1 Uncontrolled Emissions from Brick Manufacturing,
Ibs per ton, of product 7-14
7.2-2 Emission Factors Ranking for Bricks 7-T5
7.3-1 Particulate Emissions from Castable Refractories
Manufacturing 7-T9
7.3-2 Emission Factor Ranking for Cast Refractories 7-20
7.3-3 Particulate Emission Data for Castable Refractories 7-21
7.4-1 Uncontrolled Emissions from Rock Handling Processes 7-24
7.4-2 Ambient Air Particulate Concentrations Around a
Rock Quarrying and Processing Plant 7-2.6
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XI
LIST OF TABLES (continued)
7.5-1 Particulate Emissions from Gypsum Processing,
Ibs/ton throughput 7-32
7.5-2 Gypsum Emission Factor Ranking 7-32
7.6-1 Emission Factors for Sintering Operations 7-39
7.6-2 Emission Factor Rankings for Sintering Processes 7-40
7.6-3 Particulate Emissions from Sintering Operations 7-42
7.7-1 Particulate Emissions from Lime Manufacturing 7-47
7.7-2 Emission Factor Ranking for Lime Manufacturing 7-48
7.7-3 Particulate Emissions from Lime Manufacturing 7-49
7.8-1 Ranking of Emission Factors 7-52
7.9-1 Uncontrolled Particulate Emissions from Fiber
Glass Manufacturing 7-57
7.9-2 Emission Factor Ranking for Fiber Glass Manufacturing 7-58
7.9-3 Particulate Emissions from Fiber Glass Manufacturing 7-59
7.10-1 Emission Factors for Pulpboard Manufacturing 7-63
7.10-2 Emission Factor Ranking for Pulpboard Manufacture 7-64
8.1-1 Total Hydrocarbon Emissions from Dry Cleaning
Operations 8-4
8.1-2 Emission Factor Ranking 8-5
8.2-1 Gaseous Emissions from Surface Coating Applications 8-9
8.2-2 Emission Factor Ranking for Surface Coating 8-9
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XI1
LIST OF ILLUSTRATIONS
Figure No. Page
2.1-1 Particulate Particle Size from Anthracite Coal
Combustion in Stokers 2-6
2.1-2 Effect of Firing Rate on Emissions from Traveling
Grate Stokers Burning Anthracite Coal During
Normal Operations 2-11
2.2-1 Nitrogen Oxide Emissions from Dry Bottom
Pulverized, and Stoker-Fired Bituminous Coal
Burning Furnaces 2-24
3.1-1 Particulate Particle Size Distribution from
Municipal Incinerators 3-7
4.1-1 Typical Ammonia Manufacturing Process 4-3
4.3-1 General Process Flow of Furnace Process Carbon
Black Manufacturing 4-18
4.4-1 Charcoal Manufacturing Processes with Condenser 4-32
4.5-1 Example Hydrofluoric Acid Manufacturing Process 4-40
4.7-1 Typical Flow Diagram for Polyvinyl Chloride
Manufacture 4-52
4.9-1 Process Flow and Particulate Emissions from Detergent 4-64
4.9-2 Particle Size Distribution of Spray Dryer Emissions 4-66
4.11-1 Nylon Manufacturing Process 4-79
4.11-2 Viscose Rayon Manufacturing 4-80
5.3-1 Beer Manufacturing Flow Diagram 5-17
5.3-2 Typical Distilled Whiskey Flow Diagram 5-18
6.3-1 Approximate Particle Size Distribution of
Particulate from Secondary Lead Smelting 6-23
7.1-1 Ceramic Clay Manufacturing Processes 7-3
7.4-1 Particulate Size from Rock Processing Operations 7-2'5
7.6-1 Fly Ash Sintering . 7-36
7.7-1 Lime Manufacturing 7-45
7.9-1 Fiber Glass Manufacturing Process 7-55
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1. INTRODUCTION
M
This report represents a compilation of the latest\atmo-
* ' * V
spheric emission data/;a₯*4-4-able for a wide variety of selected
processes. One-half of the 40 processes discussed iB this -report
involve an updating or review of existing emission factors. -,
presented in Public Health Service Publication 999-AP-42, "A
Compilation of Air Pollutant Emission Factors" by R.L. Duprey.
The remaining factors represent new processes for which emission
factors were not previously reported. All emission factors refer
to uncontrolled processes unless otherwise stated.
Information for emission factors was gathered primarily from
the technical literature up to November 1969, state and local air
pollution control agencies, trade and professional associations,
releasable portions of data obtained by TRW in various past studies,
and individual companies and persons within the various industries
under study. In all cases, attempts were made to obtain some idea
of the validity of the information obtained, and thus place each
bit of data relative to other data in the same area. Greatest weight
was given to actual measured emission data, i.e., source tests,
especially when the measuring technique was known. Estimates of
emissions were also made when feasible by .making material balances
and process loss or yield calculations.
- "' ... ...,..,,.. *., ,.. .,.. . . ^
In general, it was found that'except for the combustion and
incineration fields, very little new emission factor data has been
made public since Oup^y^--work-in 1967. x_In_ the metallurgical and
mineral industries, additional emission data has been obtained by
various companies and control equipment manufacturers. This
information has not been made public, however. Some emission data
was available for most of the new factors developed in this report.
Frequently, however, these data were in the form of concentrations
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1-2
only, not quantitative emission rates. Process weight rates were
also frequently not given or reported. Considerable engineering
calculations were thus required in order to put these data into a
form usable for emission factors. These calculations, based on
material balances/, combustion reactions, humidity balances, and
comparisons with similar processes with available emission data,
allowed one to relate the reported data with process throughputs
and develop a factor which is usable until better data are made
available.
Detailed information used to obtain the emission factors
is general 1 y -presented-in an appen-d-ix to each section. Selection
of a final emission factor depended on the amount and range of data
available. Where considerable data existed a direct arithmetic
average was used. Values on order of magnitude greater or less
than the bulk of the data were not considered in determining the
arithmetic average. Where limited data were available (1 to 5 values)
and the values covered a wide range, the selected factor was based
on our best judgment considering the factors affecting emissions.
Whenever possible, the range or variation in emission factors was -
reported.and shown in parenthesis following the factor. This range
represents the range of values used in obtaining the factor and
represents the expected variation in emissions. A lack of information
sometimes prevented the reporting of a reasonable factor range.
Standard statistical deviations of the emission factors were
not generally reported since insufficient or only widely scattered
data were available and a significant deviation could not be calculated.
All emission factors i-n th-is-repert were ranked according to
the available data upon which they were based. -.A. system which
weighted various information categories was used to rank the final
factors.. These categories were: measured emission data with a
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1-3
total possible weight of 20, process data with a weight of 10,
and engineering analysis with a weight of 10. The highest
possible score for any factor was thus 40. Any factor ranking
less than 20 was considered questionable and those ranked 20 or
greater were considered reliable.
The emission data category rated the amount of measured
emission data, i.e., stack test data available with which to develop
an emission factor.
The process data category included such factors as the
variability of the process and its effect on emissions, and available
data on the variables. The engineering analysis category
included the data available upon which a material balance or related
emission calculation could be based.
'""-I V.
'""-£ The range of values for many emission factors is large. .........
However, when the factors are applied to a large number of sources,
the calculated overall emissions should approximate the true value.
When applied to a single isolated source, an emission factor may
yield emissions that differ considerably from the true value.
Measured emission data should therefore be used, if possible, for
single sources.
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2. STATIONARY FUEL COMBUSTION
Particulate emissions from most types of stationary fuel
combustion sources have been the subject of considerable research.
However, emissions from the combustion of some of the less common
fuels have not been determined to any great extent, nor have gaseous
1 emissions been studied in any great depth. This section concentrates
on some of these areas, and further quantifies some of these emissions,
Emissions from all types of fuel combustion are highly dependent
v . «7-an.v- '» ' -
on thlf efficiency of combustion and type of fuel. The resulting
emission factors therefore cover a wide range.
Data used to determine the emission factors presented in this
section were largely based on measured values or by comparison with
similar combustion processes.
Anthracite coal combustion yielded the following approximate
particle size breakdown (% by weight, size by microns).
Particle Size
% in Range
;'!t
No particle size data was found for wood combustion emissions,
the only^other particulate source investigated in this section.
>44
45
20-44
7
10-20
.! 8-
5-10
-
-6
<5
35
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2-2
2.1 ANTHRACITE COAL COMBUSTION
General Information
The combustion of anthracite coal is characterized by the type
of firing methods used for this fuel, and by the fuel's composition
and properties. As shown in Table 2.1-1, anthracite coal contains
very little volatile matter and sulfur, and has a relatively high
ignition temperature and ash fusion temperature as compared to
bituminous coal.
Consumption of anthracite coal has declined in recent years .
It is mainly consumed in Pennsylvania, New York, and New Jersey.
Table 2.1-1. Anthracite Coal Characteristics
Characteristic3 Pea, Buckwheat, Rice, Egg, Stove, &
and Barley Sizes Chestnut Sizes
Average Composition, Weight Percent
Water
Volatile Matter
Fixed Carbon
Ash
Sulfur
Heating Value, Btu/Pound 1
Average Ash Fusion Temperature
Average Ignition Temperature
6.2
4.2
78.1
11.5
0.7
2,300
2890°F
925°F
4.4
4.3
82.4
8.9
0.7
13,015
a) As received basis.
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2-3
Firing Practice
Due to its low volatile content, and the non-clinking characteristics
of the ash, anthracite coal is largely used in medium sized industrial
and institutional boilers using stationary or traveling grates. Anthracite
coal is not used in spreader stokers because of its low volatile content and
relatively high ignition temperature. This fuel may be burned in pulverized
coal -fired units, but due to ignition difficulties, this practice is limited
to only a few plants in Eastern Pennsylvania. This fuel has also been widely
used in hand-fired furnaces.
Combustion of anthracite coal on a traveling grate is characterized by
a coal bed depth of 3 to 5 inches (bituminous coal is usually 5 to 7 inches
deep), and a high blast of underfire air at the rear or dumping end of the
grate. This high blast of air lifts incandescent fuel particles and gases
from the grate and reflects them from a long rear arch over the grate
toward the front of the fuel bed where fresh or "green" fuel is entering. -
This special furnace arch design is required to assist in the ignition of
2
the green fuel. Additional underfire air passes up through the grate
through manually adjusted air boxes. Fuel feed rates are controlled by a
manually adjusted leveling gate at the front of the grate which regulates
the bed depth. Combustion rates are controlled by the speed of the grate
and by the underfire air rates. When automatic controls are used, the
grate speed and air rates are regulated by steam pressure. Some of the
smaller traveling grate and hand-fired units use only natural draft to
supply combustion air.
Fly ash collectors are not usually installed. However, for some of the
larger units, burning smaller sizes of coal such as Buckwheat 4 or 5, ash
carryover may be high due to the large blast of underfire air at the rear of
the grate. These units sometimes install mechanical type collectors and
2
then reinject the fly ash.
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2-4
Factors Affecting Emissions
Particulate emissions are greatly affected by the rate of firing and by
the fuel's ash content. Due to the low volatile content of the anthracite
coal, smoke emissions are rarely a problem. High grate heat release
loadings result in excessive emissions since greater quantities of under-
fire air are required to burn the fuel. Hand-fired and some small natural
draft units have lower particulate emissions since underfire air rates
cannot be increased very much. However, larger units equipped with forced
draft fans may produce high rates of particulate emissions, especially
when operating at or near rated capacity.
Multicyclones may be used on anthracite coal-fired units, and very
large units may use electrostatic precipitators to reduce particulate emissions,
Emissions
Based on stack test data, literature references, comparisons to
bituminous coal combustion, and judgments , the emission data in Table 2.1-2
were compiled. The appendix contains more detailed data and calculations
upon which these factors were based. Figure 2.1-1 presents limited
particle size data.^
As is the case with other fuels, sulfur dioxide emissions are directly
related to the sulfur content of the coal. Nitrogen oxides and carbon
monoxide emissions can be expected to be similar to those found in
bituminous coal -fired units since excess air rates and combustion temperatures
are similar. No emission data on these pollutants was found in the
literature.
Due to the lower volatile matter content of anthracite, hydrocarbon
emissions are probably somewhat lower than those from bituminous coal
combustion. Again no quantitative data were available.
-------
Table 2.1-2. Uncontrolled Emissions From Anthracite Coa/1 Combustion, Ibs/ton of coal burned
Type of Furnace
Particulate
SO,
SO
-N
HC1
CO
N(f
Pulverized (dry-bottom)
no fly ash reinjection
Overfeed Stokers9
no fly ash reinjection
Hand-fired Units
17Ab
1.7A
(1.1A-2.3A)
10A(6-15A)
38SC
38S
36S
0.5SC
0.5S
0.8S
0.03
(0.01 to
0.2
(0.1 to 0
2.5
1
0.04)
1.5 to
.3) 10 f
90
18
6 to
3
159
a) Based on data obtained from traveling grate stokers in the 12 to 180 Btu/hr heat input range.
Anthracite is not burned in spreader stokers.
b) A is the ash content expressed as weight %. For units with a multicyclone collector use 20% of this value.
c) S is the sulfur content expressed as weight %.
d) Expressed as methane.
e) Emitted as NO but expressed as NO,,. £
f) Use high side of range for smaller sized units(less than 10 x 106 Btu/hr heat input).
g) Use low side of range for smaller sized units(less than 10 x 106 Btu/hr heat input).
h) Efficiency of control devices used for anthracite are approximately - Cyclone - 75-85%
Electrostatic precipitator - 85%.
NOTE: Higher range of particulate emissions should be used for grate loadings, see Figure 2.1-2.
-------
100
.01 O.I I 10 50 90 99.99
% BY WEIGHT LESS THAN STATED SIZE
Figure No 2.1-l.pQrtjCu|ate particle size from anthracite coal combustion in stokers4
-------
2-7
Reliability of Emission Factors
Rankings based on the various factors which affect the accuracy of
emission factors are presented in Table 2.1-3.
Table 2.1-3. Ranking of Anthracite Coal Combustion Emission Factors
Particulate
SOX
HC
CO
NOX
Emission
Data
0-20
10
5
0
0
0
Process
Data
0-10
8
8
8
5
5
Engineering
Analysis
0-10
5
8
8
8
8
Total
23
21
16
13
13
Based on these rankings and arbitrarily using a mid-point of 20 as
a dividing line between good and questionable factors, it is seen that
only the particulate and SOX factors are good and the remaining factors
are questionable.
Particulate samples were gathered by methods outlined in ASME PTC 27
and Western Precipitation Company's Bulletin WP-50. Particulate data
obtained by the State of New Jersey for traveling grate stokers was largely
obtained by the Null Balance Method and by a modified U.S. Public Health
Service Method. In almost all cases particulate represents that material
collected on an alundum thimble at stack temperatures of about 300°F.
-------
2-8
Further emission research work in this area is not warranted
since the consumption of anthracite is decreasing every year, and
considerable particulate emission data already exists for the
traveling grate units which are the largest single type of unit in
common use for this fuel.
The only major assumptions made in obtaining these factors were
that hydrocarbons would approximate one-eighth of the bituminous coal
emissions and that carbon monoxide and nitrogen oxide emissions would
be similar to those found in bituminous coal combustion (see Appendix)
-------
2-9
APPENDIX 2.1
A. PARTICULATE EMISSIONS
1. Pulverized coal -fired unit - dry bottom; based on data from a
single stack test made by the State of Pennsylvania.
Coal Composition:
12.1% -
14.2% -
6.1% -
79.7% -
11,066 -
Water
Ash
Volatile Matter
Fixed Carbon
Btu/lb
Coal rate 31,300 Ibs/hr. Units equipped with cyclone and
electrostatic precipitator collection system - efficiency not
known. Measured parti cul ate emissions were 805 Ibs/hr (0.91
grs/scf, 103,200 scfm)
Based on an assumed parti cul ate collection efficiency of 80% the
inlet parti cul ate loading was:
805 = 4025 Ibs ash/hr
0.20
Amount of ash entering furnace in coal was:
31,300 Ibs coal/hr x 0.142 ash = 4450 Ibs ash/hr
% ash emitted = 4025 x 100 = 90%
4450
A 90% ash emission rate yields an emission factor of ISA Ibs parti cul ate/ ton
5
The State of Pennsylvania had used a factor of 15A. The factor for
bituminous coal, dry-bottom, pulverized coal-fired units is 17A. Since
the anthracite value is close to this, but based on only one test and on
an assumed fly ash collection efficiency, use the bituminous coal factor of 17A.
-------
2-10
2. Traveling Grate Stokers
Considerable stack test data from the State of New Jersey is
shown in the Table 2.1-4 and plotted in Figure 2.1-2. Consider-
able variations in these data are evident. The arithmetic mean
values of percent ash emitted in various ranges of grate heat
release rates, and their variances are shown in Table 2.1-5.
Table 2.1-5. Average Particulate Emission From Anthracite Coal Combustion
in Traveling Grate Stokers
Operating Mode Grate Heat Release
Rate 106 Btu/ft2 -
hour
Normal
(40-70% of Capacity)
Soot Blowing
0.12 to 0.24
0.25 to 0.31
General
General
Emissions
% of Inlet lb/106
Ash Btua
5.6 ± 5.6
.11.6 ± 3.9
8.3 + 5.9 0.685
26.8 + 18.2 2.2
Factor6
1.1A
2.3A
1.7A
5A
a) Based on average ash content of 10.4% and heating value of 12,600 Btu/lb.
b) A is the percent ash in the coal
The State of New York uses 15/ton as particulates emission from
anthracite coal combustion. This is equivalent to an emission factor of
1.5A for a coal containing 10% ash. Their factor was based on bituminous
coals combustion.
The State of Pennsylvania used the same factors for anthracite and
5
bituminous coals combustion, namely:
Underfeed Stoker 3A Ibs/ton (A=% ash in coal)
Traveling Grate 3A Ibs/ton
The State of Pennsylvania has, however, now accepted the factors used
by the National Air Pollution Control Administration for bituminous fuel
combustion; namely 5A.
-------
2-11
CM
s-
O)
Q.
3
4->
CO
10
o
-------
TABLE 2.1-4. ANTHRACITE COAL EMISSION DATA
COMPANY RUN FUEL Btu/hr H.S Ash/hr GRATE
Plant A
Plant B
Plant C
Plant D
Plent E
1
2
3
4
5
1
2
3
4
5
1
2
3
1
2
3
1
2
3
4
5
Ib/hr
5150
4566
6181
4446
4434
2265
2201
2076
2332
2580
3132
2765
2100
3000
.3050
3395
1140
1C45
1190
1280
1150
% Ash
12.5
12.5
12.5
12.5
12.5
7.2
7.2
7.2
9.8
9.8
11
12.1
12.1
10.5
10.5
10.5
11.5
11.0
9.9
11.2
10.9
Btu/lb
|_\
. 13,3f;0
12,533
lo,052
13,123
13,055
K.337
14,337
14,337
14,089
14,089
12,855
12,733
12,733
13,000
13,000
13,000
12,895
12,991
13,198
13,023
13,059
106
68.1
57.2
80.7
58.3
57.9
32.5
31.5
29.7
32.85
36.3
40.3
35.2
26.7
39.0
39.65
44.1
14.7
13.6
15.7
16.7
15.0
645
570
770
555
555
163
159
149
228
253
344
334
254
315
320
356
131
115
118
143
125
Area ft2
482. 5
4C2.5
482.5
482.5
482.5
141
141
141
141
141
141
100
100
100
100
100
6tu/ft2-hr
.14
.12
.168
.121
.12
.285
.25
.188
.276
.28
.25
.15
.14
.16
.17
.15
FMIWION
lbs/hr
11.8
13.3
81.7
17.4
50.2
56.9
17.6
27.5
150.7
103.2
27.2
13.5
107.5
48.7
159.1
64
3.7
51.4
5!J.9
7.2
5.76
lb/106Btu % of Inlet
Ach
.17
.23
1.0
.30
.81
1.75
.56
.93
4.5
2.8
.67
.38
4.0
1.2
4.0
1.45
.25
4.0
3.5
0.43
0.36
1.8
2.3
10.2
3.1
9.1
35
11
18.2
66
41
7.9
*.l
42.4
15.5
49.7
18.0
2.8
47.3
47.6
5
4.6
COMMENTS
Natural Draft
for all Runs in A
Soot Blow
Soot Blow
Soot Blow
Soot Blow
UnusuallyHigh (omit)
66% of Full Load
Soot Blow
Soot Blow
Forced Draft
Soot Blew
Soot Blow
ro
-------
UJ-IKKNT KUM
Plant F
Plant G
Plant H
Plant I
Plant J
1
2
3
1
2
3
1
2
3
4
1
2
3
4
5
1
2
3
rutL
Ib/hr % Ash Btu/lb
11,682
8,805
5,704
5,940
3,963
5,634
9,259
5,480
8,958
£.355
14,195
14,265
12,891
li!, 41 7
11,357
13,900
13,400
10,600
14.3
14.3
14.3
12
12
12
12.7
12.7
12.7
12.7
11.3
11.3
11.3
11.3
11.3
10
10
10
12,300
12,300
12,300
12,874
12,874
12,874
12,212
12,212
12,687
12,687
12,845
12,845
12,677
12,677
12,677
12,800-
12,800-
1 2 .800-
Btu/hr Ibs Ash/hr
106
143.7
108.3
70.16
76.5
51.0
72.5
113.1
66.9
113.6
106.
182.3
183.2
163.4
1EJ.4
143.9
178
172
135.5
1670
1260
815
712
476
675
1180
696
1140
1060
1600
1610
1460
1408
1285
1390
1340
1060
GRATE EMISSION
Area Ft2 Btu/ft2-hr
106
344
344
344
348
348
3^8
372
372
372
372
672
67Z
672
67?
67L
582
582
582
.42
.31
.204
.22
.147
.21
.31
.18
.304
.28
.27
.27
.245
.234
.214
.306
.295
.232
Ibs/hr lb/106Btu % of Inlet
Ash
163.7
169,0
213.3
135.6
136.5
U6.3
128.5
78.5
200.7
9?. 7
252
337.3
182. 3
153.9
193.3
160
130
330
1.13
1.E6
3.03
1.77
2.60
1.74
1.13
1.17
1.76
.90
1.38
1.84
1.15
0.98
1.34
0.9
0.75
2.44
9.8
15.6
28.8
19.0
2C.7 ,
18.7
10.9
11.2
17.6
9.0
15.7
21
10.9
9.5
13.1
11.5
9.7
31
COMMENTS
No Soot Blown
in F.G.H
Appear High
Appears High
Soot Blow
Soot Blow
76% of Load
Scot Blow
PO
I
co
-------
COMPANY RUN
PUnt K
Plant L
Plant M
Plant N
Boiler #
1
a & b
2
3
1
4
5
6
7
1
2
1
: -2
3
4
5
6
FUEL
Ib/hr % Ash Btu/lb
3,394
3,910
3,580
1 ,308
1,090
2,050
2,265
1,894
6,989
7,300
960
920
960
1,040
1,340
955
11.3
9.4
9.4
10.9
10.5
10.5
10.5
10.5
11.4
11.4
13.3
13.3
13.9
13.9
11.6
11.6
It, 848
13,104
13,104
13,256
13,237
13,145
13,145
13,145
13,127
13,127
12,779
12,779
12,556
12,556
12,987
12,987
Btu/hr Ibs Ash/hr
106
43.6
51.2
46.9
17.3
14.4
26.9
29.8
24.9
91.7
96
12.3
11.7
12.05
13.1
17.3
12.4
364
367
336
142
114
211
238
199
800
830
127
122
133
H5
156
111
GRATF EMISSION
Area Ft2 Btu/ft2-hr
196
196
196
120
120
120
120
120
348
348
64
64
64
64
64
64
.222
.261
.24
.14
.12
.224
.248
.208
.264
.275
.19
.185
.189
.204
.27
.195
Ibs/hr 1b/106Btu % of Inlet
'Ash
5.6
26.7
6.6
6.35
2.76
1.93
32.3
2.5
79.2
67.7
3.83
1.83
4.83
13.9
23.4
15.8
.13
.52
.14
.37
.19
.072
1.09
0.1
.86
.705
0.32
0.16
0.4
1.07
1.3
1.27
1.4
7.3
1.9
4.45
2.4
0.9
13.5
1.2
9.9
8.1
3.0
1.5
3.6
9.6
15.0
14.3
COMMENTS
Fly Ash Reinjected
50% - Load
Forced Draft
Appears Low
Soot Blow
80% Load, Forced
Craft
Soot Blown foH min.
(No Effect)
51% Load -, Natural
Draft
Soot Blow
i,
II ||
ro
i
-------
2-15
3. Hand-Fired Units:
The State of Pennsylvania used 24-54 Ibs/ton of coal for both
anthracite and bituminous.5 These figures appear high because
they include smoke and tars, and these substances are not as
prevalent with anthracite.
The State of New York used 15 Ib/ton for all anthracite
combustion.6 Blackie reports particulate emissions from
domestic hand-fired units with anthracite to be 6 Ibs per
ton of coal. Smith reports values from 6-10 Ibs/ton for
anthracite combustion in hand-fired equipment;^ these data are,
however, rather old. Hand-fired units burn the larger sized
coals such as egg and stove which contain about 9% ash.
Based on the above information, an emission factor of 10 Ibs per
ton of coal was selected.
B. GASEOUS EMISSIONS
1. Sulfur Oxides
A stack test performed by the State of Pennsylvania on a traveling
grate stoker burning anthracite coal with a sulfur content of
0.65% yielded emissions of 117 Ibs/hr of S02 at a fuel rate of
about 11,400 Ibs/hr.
% S emitted = 100 x 1V7 = 11700 = 79%
11,400 x .0065 x 2 148
Based on earlier work on bituminous coal presented in the
literature, approximately 95% of the sulfur in the fuel appears
5 7
as S02 and about 1% appears as S03 in the flue gas. '
There is no large body of evidence to show that this value should
be different for anthracite coal fired in large units. Limited
data indicates that for hand-fired units the amount of sulfur
8,9
emitted amounts to 90% as S02 and 1.5% as S03-
-------
2-16
Based on the above information the following emission factors
for SOX were calculated:
Hand-fired units - 36S Ibs S02 per ton coal, where
S = % sulfur by weight in fuel
0.76S Ibs SO, per ton coal
0.90S x 64/,0 = Ibs SCL/lb coal; 1.8S x 2000 = 36S Ibs S09/ton
Oc & _ . ^
100
By a similar calculation, emissions for stoker and pulverized
units are: 38S Ib S02 per ton coal
0.5S Ibs S03 per ton coal
2. Hydrocarbon Emissions
Due to the lower volatile content of anthracite coal (4.2% vs 30-40%
for bituminous coal), the hydrocarbon emissions are 'probably lower.
No quantitative data are available however. Based on a bituminous
coal factor of 20 Ibs of hydrocarbon per ton of coal, New York State
took one-eighth of this value (ratio of volatile matter in
anthracite coal to bituminous coal) and arrived' at a generaV emission
factor of 3 Ibs per ton. Since hydrocarbon emissions originate
from the volatile matter in the fuel and are due to its
incomplete combustion, a factor based on about one-eighth of the
values used for bituminous coal appears reasonable. These values
are listed on Table 2.1-6.
Firing Method Bituminous Coal Anthracite Coal
Table 2.1-6. Hydrocarbon Emission Factors
jminous Coa
Ibs/ton Ibs/ton
Pulverized 0.11 to 0.35 0.012 to 0.044
Stoker 1 to 2.5 0.12 to 0.3:
Hand-Fired 20 2.5
-------
2-17
3. Nitrogen Oxides and Carbon Monoxide
The emission of these compounds is affected by the firing
method used and not by the type of coal. Since no quantitative
emission data were found, the factors used for bituminous coal
were selected as shown in Table 2.1-2 and based on data
developed in Section 2.2.
-------
2-18
REFERENCES 2.1
1. Physical and Chemical Properties of Pennsylvania Anthracite,
Anthracite Institute, Wilkes Barre, Pennsylvania.
2. Steam, Its Generation and Use. New York, Babcock and Wilcox
Company, New York, 1963, p. 16-2 to 16-6.
3. Blackie, A. Atmospheric Pollution from Domestic Appliances,
The report of the Joint Conference of the Institute of Fuel and
the National Smoke Abatement Society; London, February 23, 1945.
4. New York - New Jersey Air Pollution Abatement Activity Phase II,
December 1967, p. 58.
5. Anderson, D.M., J. Lieben, and V.H. Sussman, Pure Air for Pennsylvania,
Pennsylvania Department of Health, Harrisburg, Pa., November 1961,
p. 15.
6. Hovey, H.H., et al. The Development of Air Contaminant Emission
Tables for Non-Process Emissions, J. Air Pollution Control Association,
JJK 362-366, July 1966.
7. Smith, W.S., and C. Gruber, Atmospheric Emissions From Coal Combustion.
National Air Pollution Control Administration, Raleigh, North Carolina,
Public Health Service Publication 999-AP-24. April 1966, p. 76.
8. Crumley, P.M., and A.W. Fletcher. J. Inst. of Fuel Combustion,
30:608-612, 1957.
9. Chicago Association of Commerce, Committee of Investigation, Smoke
Abatement and Electrification of Railway Terminals in Chicago,
Chicago Rand McNally Company, 1915. p. 1143.
10. Section 2.2, infra.
-------
2-19
GENERAL REFERENCES
Nomograph to Determine the Heating Value of Anthracite Coal.
Combustion, p. 41, Novemebr 1968.
Morgan, R.E., and 0. Ratway. Anthracite's Relation to Air Pollution
Control. Coal Heat. 73: 35-38, July 1957.
Browning, W.J. The Composition of Solids Emitted from Domestic
Boiler Fireboxes. Fuel. J5.(10): 284-286, 1936.
-------
2-20
2.2 BITUMINOUS COAL COMBUSTION - GASEOUS EMISSIONS
General -
Coal is the most plentiful fuel in the United States, and
is burned in a wide variety of furnaces to produce heat and
steam. Coal -fired furnaces range in size from small hand-fired
units with capacities of 10-20 pounds of coal per hour to
large pulverized coal-fired units which burn 300-400 tons of
coal per hour.
Although predominantly carbon, coal contains many compounds
in varying amounts. The exact nature and quantity of these
compounds is determined by the source of the coal and will
usually affect the final use of the coal.
Particulate and sulfur oxide emissions from coal combustion
have received considerable attention, but the other gaseous
emissions which are less noticeable have not been the subject
of intensive investigations.
Emissions of gaseous hydrocarbons, carbon monoxide and
nitrogen oxides are currently not reduced by using control
equipment. They can, however, be reduced by optimum adjustment
of combustion conditions as discussed in the next section.
Factors Affecting Emissions
The carbon monoxide and hydrocarbon content of the gases
emitted from bituminous coal combustion depend mainly on the
efficiency of combustion. Complete combustion and a low level
of gaseous carbon and organic emissions involves a high degree
of turbulence, high temperatures, and sufficient time for the
-------
2-21
combustion reaction to take place. Thus, careful control of
excess air rates, high combustion temperature, and intimate fuel-
air contact will minimize these emissions.
Since the larger furnaces are usually better equipped to
control air and fuel feed rates, they have lower gaseous emission
rates. Smaller furnaces, both manual and stoker-fired, have less
control over air and fuel rates and combustion temperatures, and
produce higher emissions. Composition of the bituminous coal does
not apparently have any significant effect on these emissions.
Emissions of nitrogen oxides result primarily from the high
temperature reaction of atmospheric nitrogen and oxygen in the
combustion zone. The main factors affecting these emissions are
furnace temperature, residence time in the furnace, and the rate of
gas cooling. Generally, larger more efficient combustion units yield
higher nitrogen oxide emissions. The practice of preheating
combustion air at large boilers is considered a significant reason for
the resultant higher NOX release.
Since some of the factors affecting gaseous emissions such
as combustion temperatures or excess air rates are frequently not
readily apparent to the operator, the emissions of these compounds
tend to vary over a wide range. Reported CO and hydrocarbon emissions
vary 3 to 4 orders of magnitude among smaller combustion sources.
(See Appendix).
Emissions
Selected gaseous emissions from bituminous coal combustion are
presented in Table 2.2-1. The size range in Btu per hour for the
various categories is shown only as a guide in applying these
factors and cannot be used as a clear demarcation between furnace
applications. The actual values selected are based on engineering
judgment and on knowledge and involvement with most of the tests.
Due to their higher firebox temperatures, cyclone-fired
furnaces and other types of wet bottom burnaces produce greater
-------
2-22
concentrations of nitrogen oxides. However, longer residence
time in the conventional wet bottom furnace appears to reduce
concentrations again by causing decomposition of the oxide.
Table 2.2-1. Selected Gaseous Emissions from Bituminous Coal
Combustion.
Lbs/ton of Coal Burned
Furnace Size,
10° Btu/hr heat input
1. Greater than 100 -
utility and large
industrial boilers
General -dry bottom
Cyclone Furnaces
N0xa CO HCb
18 1 (0.1-3) 0.25 (.11-1)
55 1 (0.1-3) 0.25 (.11-1)
2. 10 to 100
large commercial and
general industrial
boilers, stoker-fired 15 1.5 (1-3) 1 (0.2-20)
3. Less than 10
s.toker-fired commercial
and domestic furnaces 6 10 (4.5-31) 2.5 (1-3.3)
4. Hand-fired Units 3 90 20
a) Expressed as N0£. The equation, log NO^ = 1.165 log (hourly
heat input) - 7.6081, represents NOX emissions from dry bottom
pulverized and stoker fired units and can be used to estimate
hourly NOX emissions.
b) Expressed as methane.
Carbon monoxide and hydrocarbons are generally emitted at
concentrations of 5-50 ppm under normal combustion conditions in
stoker-fired units.
-------
2-23
Nitrogen oxides are mainly emitted as nitric oxide (NO) at
concentrations of about 100 to 500 ppm, except for the large
cyclone-fired units which emit concentrations in the range of
700 to 1200 ppm. Relationships between Btu input and hourly
emission of NOX may be found in the literature. » '° For larger
combustion sources, an empirical relationship which expresses
NOX emissions in terms of heat input would probably be more
accurate than using a general emission factor. Based on emission
data available for this review (excluding cyclone furnaces), the
equation:
log NOY = 1.165 (log heat input) - 7.608
/\
was derived. This equation gives the NO emissions in Ibs/hr when
A
the hourly heat input is known. Figure 2.2-1 shows this relationship.
Reliability of Emission Factors
Gaseous emissions from bituminous coal combustion vary widely
since they are affected by many variables some of which are not
easily controlled. Thus, emissions even from the same furnace
will vary from day to day since only a small change in the
efficiency of combustion can greatly affect carbon monoxide and
hydrocarbon emissions. It must be realized, that these pollutants
are only emitted in ppm quantities, and they are not easily
measured with a great degree of accuracy.
Nitrogen oxide emissions are also affected by many variables
and thus cover a wide range. However, these emission data correlate
well with furnace size and are representative of the true emission.
Table 2.2-2 ranks the emission factors and indicates that
they are fairly reliable.
-------
2-24
10'
^ 10.0
3E
$ ..o
,~
E
LU
i
10
-I
10
10
,-4
10'
Log NOX =1.165 Log (Heat Input)
-7.6O8
10'
10'
10
8
10"
Gross Heat Input to Furnace in Fuel
Btu/hr.
10
10
Figure 2.2-1 .Nitrogen Oxide Emissions from Dry
Bottom Pulverized, and Stoker-Fired
Bituminous Cool Burning Furnaces.
-------
2-25
Table 2.2-2. Gaseous Emission Factor Ranking for
Bituminous Coal
NOX
CO
HC
Emission Data
0-20
12
10
10
Process Data
0-10
7
7
7
Engineering Analysis
0-10
8
5
5
Total
27
22
22
-------
2-26
APPENDIX 2.2
A. NITROGEN OXIDE EMISSIONS
1. Furnaces larger than 100 x 10 Btu/hr heat input
Large Industrial and Public Utility Sizes
Full Load Tests
Pulverized Coal
lbs/106Btu
0.55
0.71
0'.95
Avg. 0-74
Dry bottom
Ibs/ton Coal
13.0
17.1
24.8
18.3
Reference
4
4
4
Cyclone -Fi red
2.2
61
Other Firing Methods, Stokers, etc.
0.76 19.2 4
0..59 15.6 - wet bottom furnace 4
Partial Load Tests
Pulverized Coal
lbs/T06Btu
0,31
0.51
0.74
Avg. 0.52
Dry bottom
Ibs/ton Coal
7.3
13.7
19.3
13.4
4
4
4
-------
2-27
1bs/106 Btu Ibs/ton
$.*>
Cyclone-Fired
1.8 55 4
Other Firing Methods
0.68 17.2 4
0.56 14.8 - wet bottom 4
furnace
Data not designating load or type of unit
0.17 to 2.5 4.1 - 60 5
0.12 to 2.4a 3-20 1
2.3a 19.2 2,3
A value of 18 Ibs/ton was chosen for dry bottom units, and
55 for cyclone units.
2. Furnaces in the 10 to 100 x 10 Btu/hr heat input range.
Large Commercial and General Industrial Sizes; Under-
feed or Overfeed Stokers
lb/106Btu Ibs/ton Reference
20 (estimate) 6,7
0.8 19.2 2,3
Note, Oil-fired units in this size range emit 12-17 Ibs
N0x/ton.
Factor chosen based on data for both larger and smaller
sized units and on relationship in Figure 2.2-1, was
15 Ibs. NO/ton coal.
X
a) Based on 25 million Btu per ton.; of coal.
-------
2-28
3. Furnaces less than 10 x 10 Btu/hr heat input stoker-fired
including residential.
lbs/10 Btu Ibs/ton fuel Reference
0.30 8.3 9
0.36 9.8 9
0.4 7
0.5 8
Hand-Fired Units
0.11 3.2 9
Factor chosen was 6 and 3 Ibs/ton of fuel respectively
for small stokers and hand-fired units.
B. CA'RBON MONOXIDE AND HYDROCARBON EMISSIONS
1. Furnaces larger than 100 x 10 Btu/hr heat input
CO HCa Reference
1;
Avg.
b's/106Btu
0.017
'0.011
0.005
$.10
0.044
tU)35
Other bafca- 0
Value
$..029
.0..51
chosen for
Ibs/ton
0
0
0
2
1
0
.1
0
12
PULVERI
.41
.26
.13
.8
.16
.95
- 0.6
STOKE R-
.73
lbs/106Btu
Ibs/ton
ZED COAL
0.
0.
0.
0.
0.
0.
FIRED
0.
0,
013
005
013
004
001
007
-
012
005
0.
0.
0.
0.
0.
0.
0.34
0.
0.
32
13
35
11
35
25
- 1.25
31
11
3
3
3
9
3
1
3
9
,4
,4
,4
,4
c
,4
b
factor -"
1
0.
25
a) Expressed as methane. Data from reference 3 & 4 converted from
carbon to methane by multiplying by 16/12.
b') tfld'unit without modern combustion controls.
c) 'Data 'from reference one converted from hexane to methane.
-------
2-29
2. Furnaces in the 10 x 106 to 100 x 106 Btu/hr heat input range,
CO
lbs/106Btu
0.1
.
Ibs/ton
3
1
HC
lbs/10°Btu Ibs/ton
0.0045 0.16
20
14 - 26
Reference
9
6
7
3.
Since very limited and scattered data are available for
furnaces in the 10 x 10 to 100 x 10 Btu/hr heat input range,
the final CO and HC factor was chosen by picking values
between the factors for the larger and smaller stoker-fired
units and not on the values reported above. Values chosen were
1.5 Ibs/ton for CO and 1 for HC.
Furnaces less than 10 x 10 Btu/hr heat input.
CO HC Reference
lbs/106Btu
Avg.
Value
0.16
0.14
1.1
0.47
chosen
Ibs/ton lbs/106Btu
STOKER-FIRED
4.5
3.9
31
1.3.1
10
0.116
0.036
0.12
0.095
Ibs/ton
3.2
1.0
3.3
2.5
2.5
9
9
9
HAND-FIRED
3.5
99
0.73
21
-------
2-30
REFERENCES 2.2
1. Perry, H., and J.H. Field. Air Pollution and the Coal
Industry. Transactions of the Society of Mining Engineers.
December 1967.
2. He.ller, A.W., and D.F, Walters. Impact of Changing Patterns
of Energy Use on Community Air Quality. J. Air Pollution
Control Assoc., J_5_:426, September 1965.
3. Smith, W.S., and C.W. Gruber. Atmospheric Emissions from
Coal Combustion, An Inventory Guide. National Air Pollution
Control Administration, Raleigh, N.C. Public Health Service
Publication 999-AP-24. p. 91.
4. Cuffe, S.T., and R.W. Gerstle. Emissions from Coal-Fired
Power Plants, A Comprehensive Summary. National Air Pollution
Control Administration, Raleigh, N.C. Public Health Service
Publication 999-AP-35. 1967. p. 15.
5. Austin, H.C. Atmospheric Pollution Problems of the Public
Utility Industry. J. Air Pollution Control Assoc., 10(4): 292-294,
August, 1960.
6. Hovey, H.H., A. Risman, and J.F. Cunnan. The Development
of Air Contaminant Emission Tables for Non Process Emissions..
J. Air Pollution Control Assoc., j^_:362-366, July 1966, and
private communication with New York State Health Dept.
7. Anderson, D.M., J. Lieben, and V.H. Sussman. Pure Air for
Pennsylvania. Harrisburg, Pa. Pennsylvania Dept. of Health.
November 19&1. p. 91-95.
8. Communication with National Coal Association. Washington, D.C.
September 1969.
9. Hangebrauck, R.P., et al. Emissions of Polynuclear Hydrocarbons:-
and-Other Pollutants from Heat - Generation and Incineration
Processes. J. Air Pollution Control Assoc., 14:267-278,
July/ 1964.
-------
2-31
10. Wool rich, P.P. Methods for Estimating Oxides of Nitrogen
Emissions from Combustion Processes. American Ind. Hyg.
Association, J. 22_:481-484, 1961.
GENERAL REFERENCES
La Manita, C.R., and E.L. Field. Tackling the Problem of
Nitrogen Oxides. Power. April 1969. p. 63-66.
Singer, J.M., et al. Flame Characteristics Causing Air Pollution:
Production of Oxides of Nitrogen and Carbon Monoxide. Bureau of
Mines, R.I. #6958, 1967.
Fernandes et al. Boiler Emissions and Their Control. Combustion
Engineering. 1966.
Barnhart, D.H., and E.E. Diehl. Control of Nitrogen Oxides in
Boiler Flue Gases by two-Stage Combustion, J. Air Pollution Control
Assoc., 10(5):397-406, October 1960.
An Appraisal of Air Pollution in Minnesota. Minnesota State
Department of Health, January 1961.
Terrill, J.G., E.D. Howard, and I.P. Leggett. Environmental
Aspects of Nuclear and Conventional Power Plants. Industrial
Medicine and Surgery. June 1967.
Interstate Air Pollution Study, Phase II, St. Louis Project Report,
Air Pollution Emission Inventory. National Air Pollution Control
Administration.
Giever, P.M. The Significance of Carbon Monoxide as an Air
Pollutant. University of Michigan. ( Presented at American Institute
of Chemical Engineers'. Detroit Meeting. December 8, 1969.)
The Contribution of Power Plants and Other Sources to Suspended
Particulate and S02 Concentrations in Metropolis, Illinois.
National Air Pollution Control Administration. Raleigh, N.C. 1966.
-------
2-32
Steam - Electric Plant Factors. National Coal Association.
Washington, D.C. 1968.
Air Pollution Aspects of Thermal Power Plants - An Annotated
Bibliography. National Air Pollution Control Administration.
Raleigh, N.C. March 27, 1968.
-------
2-33
2.3 HYDROCARBON EMISSIONS FROM FUEL OIL COMBUSTION
IN POWER PLANTS
General Information
Residual or Grade 6 fuel oil is the major liquid fuel
used by electric power generating stations and accounts for
approximately 8.5% of all fuel burned at power stations.3 This
fuel oil is a component of the higher boiling residue resulting
from the distillation of crude petroleum. Its viscosity is high
and it requires heating for efficient transfer and injection
into the boiler. The average analysis of #6 or residual oil is
86% carbon, 10% hydrogen, 1.0% water, 0.5% nitrogen, 1.6% sulfur,
p
and the remainder ash. However,wide variations in composition
may occur depending on the crude oil and refining practices used
to produce the residual fuel. Grade 6 oil has a heating value of
about 18,300 Btu/pound.b Many boilers use coal, oil, and natural
gas interchangeably and sometimes simultaneously.
Factors Affecting Emissions
The major factors affecting hydrocarbon emissions at oil
fired power plants are the quantity of oil used and the efficiency
of combustion within the furnace. This efficiency is affected
i
in turn by the temperature of the injected oil, the composition
of the oil, the pressure and temperature of the fuel at the burner,
and the excess air rates. "The key to optimum oil burner
3
operation is careful control of fuel viscosity." Viscosity of
the fuel entering the burner should be less than 150 Saybolt S.econds
Universal (SSU).
In order to burn properly, oil must be atomized as it enters
the combustion chamber. . This atomization provides a high degree
a) On a Btu basis, Reference 1.
b) Approximately 147,000 Btu/gallon.
-------
2-34
of air/fuel mixing and exposes a large amount of droplet surface
area to the heat of the combustion zone. There are three basic
types of oil atomizers; namely, air, steam,and mechanical (rotary
cup). However, steam atomizers are most commonly used at
power plants. In this type of atomizer, steam at a pressure
greater than 100 psi and hot oil (170 - 260°F) are mixed in the
burner nozzle and then sprayed into the combustion chamber.
The oil mixture is this atomized as it passes out through the
burner's nozzles.
Oil burners are usually mounted in banks inside the
boiler's firebox. As many as 24 burners may be mounted in a
large furnace, either all in a single side in rows (front-wall
fired) or in sets in the four corners of the boiler (tangentially
or corner fired). Excess air rates on the order of 15 to 30%
are usually used. Under ideal firing and combustion conditions
the hydrocarbon emissions are very low.
Emissions
Based on data presented in Appendix 2.3, the hydrocarbon
emission factor for oil-fired power plants shown below was
determined:
0.25 lbs/1000 Ibs of oil burned or 2 lbs/1000 gallons of
oil burned, when the hydrocarbons are expressed as methane.
The range of values reported in the literature was 0.1 to 0.4 Ibs
per 1000 pounds of fuel oil.
Reliability of Emission Factor
Only references to actual source tests based mainly on work
conducted by the Los Angeles County Air Pollution Control District
-------
2-35
in the late 1950's were used to determine these emission factors.
However, due to the limited number of these data, the complicated
techniques required to measure rather low concentrations, and the
limited geographical area in which tests were made, further work
in this area should be done. Data on the composition of these
hydrocarbons would also be useful. The numerical ranking for
this factor is presented in Table 2.3-1.
Table 2.3-1. Emission Factor Ranking for Hydrocarbons
Emission Data Process Data Engineering Analysis Total
0-20 0-10 0-10
5 8 2 15
-------
2-36
APPENDIX 2.3
Emission Data from the Literature
Data Reference
0.4 Ibs methane/1000 Ibs of oil 4
0.097 Ibs hexane/1000 Ibs of oil j$,6 (same data)
0.19 Ibs hexane/ton of oil 7 (1 ton oil = 244 gals)
0.56 Ibs hexane/ton of oil 7
13 pprn (0.324 Ibs propane/1000 Ibs of oil) 8
Converting these values to methane3, and putting them on a common
basis of lbs/1000, we have:
0.40 Ibs methane/1000 Ibs oil
0.11 Ibs methane/1000 Ibs oil
0.11 Ibs methane/1000 Ibs oil
0.31 Ibs methane/1000 Ibs oil
0.35 Ibs methane/1000 Ibs oil
Total =1.28 Avg = 0.256
a) Pounds of hexane are converted to equivalent pounds of methane
by multiplying by 96/86. Pounds of propane are converted to
methane by multiplying by 48/44.
-------
2-37
REFERENCES 2.3
1. Steam Electric Plant Factors. National Coal Association,
Washington, D.C. 1968. p. 87.
2. Smith, W.S. Emissions From Fuel Oil Combustion. National
Air Pollution Control Administration, Raleigh, N.C. Public
Health Service Publication 999-AP-2. 1967. p. 5.
3. Walsh, R.T. Gaseous and Liquid Fuels. In: Air Pollution
Engineering Manual. Danielson, J.A. (ed.). National Air
Pollution Control Administration, Raleigh, N.C. Public Health
Service Publication 999-AP-40. 1967. p. 520.
4. Terrill, J.G., E.V. Howard, and I.P. Leggett. Environmental
Aspects" of Nuclear and Conventional Power Plants. Industrial
Medicine and Surgery. June 1967.
5. Weisburd, M.I., and S.S. Griswold (eds.). Air Pollution Control
t;Field Operations Manual. National Air Pollution Control
Administration, Raleigh, N.C. Public Health Service
Publication #937. 1962. p. 27.
6. Chass, R.L., et al. Total Air Pollution Emissions in Los
Angeles County. J. Air Pollution Control Association.
10(5):351-366, October 1960.
7. Kanter, C.V., R.G. Lunche, and A.P. Fudurich. Techniques
for Testing Air Contaminants from Combustion Sources. J. Air
Pollution Control Association. 6_(4) :191-198, February 1957.
8. Feldstein, M., et al. The Collection and Infrared Analysis
of Low Molecular Weight Hydrocarbons From Combustion Effluents.
American Industrial Hygiene Association J. 20:374-378.
October 1959.
-------
2-38
GENERAL REFERENCES
An Appraisal of Air Pollution in Minnesota. Minnesota State
Department of Health. 1961.
The Contribution of Power Plants and Other Sources to Suspended
Particulate and S02 Concentrations in Metropolis, Illinois,
U.S; Public Health Service. National Air Pollution Control
Administration. 1966.
Emissions of Oxides of Nitrogen from Stationary Sources in Los
Angeless Report #3, Los Angeles County Air Pollution Control
District; July 1961.
Chaney, A,L. Significance of Contaminants from Central Power
PI ants.
Preparation, Sampling, and Assay of Synthetic Atmospheres.
Stanford Research Institute Project, 1816 Stanford University,
1956.
Magilli P.L., and R.W. Benoliel. Air Pollution in Los Angeles
County-, Contribution of Combustion Products. Industrial Engineering
Chemistry. 44:1347, 1952.
Removal of Particulate and Gaseous Contaminants from Power Plant
Flue Gases, Air Pollution Control Association, 1st Technical
Meeting, 1957.
Heller, A.W., and D.F. Walters. Impact of Changing Patterns of
Energy Use on Community Air Quality. J. Air Pollution Control
Association. 1_5_:426, September 1965.
-------
2-39
2.4 LIQUEFIED PETROLEUM GAS COMBUSTION
General Information
Liquefied petroleum gas, commonly referred to as LPG, consists
mainly of butane, propane, or a mixture of the two, and trace amounts
of propylene and butyl ene. This gas, obtained from oil or gas wells,
or as a by-product of gasoline refining is sold as a liquid in metal
cylinders under pressure. It is therefore often called bottled gas.
Butane, CyH-jQ, boils at 31.T°F and propane, C3HQ, boils at
-43.8°F. The use of these gases is therefore limited to those areas
with ambient temperatures generally higher than these, since
vaporization is greatly impaired at temperatures approaching the
boiling point. LP gases are graded according to maximum vapor pressure
with Grade A being predominantly butane, Grade F .being predominantly
propane, and Grades B thru E consisting of various mixtures of butane
and propane. Generally, sulfur content is less than one grain per
hundred cubic feet of vapor, although variance is not uncommon. The
heating value of LPG ranges from 3200 ^=- for Grade A to 2500 ^F=- for
Grade F. .
The use of LPG has grown from 77 million gallons in 1935 to
14,466 million gallons in 1967 and is expected to top 43,500 million
gallons in 1978. The largest market for LPG is presently the
domestic-commercial heating market which consumed 43.0% of the 1967
total. The chemical industry and internal combustion engines consumed
37.6% and 8.0% of the 1967 total respectively. Annual utility use
accounted for 97 million gallons or only 0.67% of the 1967 total,
registering a decline for two straight years (1966 and 1967).
This fuel is considered a "clean" fuel because of the lack
of visible emissions. Gaseous pollutants such as carbon monoxide,
hydrocarbons, and nitrogen oxides do occur, however.
a) Equal to 337,000 Btu per gallon.
b) Equal to 308,000 Btu per gallon.
-------
2-40
Factors Affecting Emissions
The most significant factor affecting emissions is the burner
2
design, adjustment, and venting. Improper design, blocking and
clogging of the flue vent, and lack of combustion air will result
in improper combustion causing the emission of aldehydes, carbon
monoxide, hydrocarbons, and other organics.
Nitrogen oxide emissions are a function of a number of variables
including temperature, excess air, and residence time in the
combustion zone. These variables in turn are a function of hydrogen
to carbon ratio in the fuel and to furnace design. Since the
o
hydrogen to. carbon ratio for LPG is similar to fuel oil, and
combustion chamber designs are similar to natural gas fired units,
a nitrogen oxide emission between that of fuel oil and natural gas
combustion is probable.
The amount of S02 emitted is directly proportional to the amount
of sulfur in the fuel.
Emissions
There have been no published results of source testing of
stationary sources using LPG nor have any unpublished results been
found. However, due to the similarities between LPG and natural gas,
it is felt that for most emissions, the data used to compute
emission factors for natural gas combustion when put on a Btu basis
may be reasonably used when considering LPG. For nitrogen oxides
a factor based on both fuel oil and natural gas was used. Factors
based on these data as shown in the Appendix are presented in Table 2.4-1
In some instances, the sulfur content in LPG may be different than
that normally found in natural gases thus affecting the amount of S02
produced. Therefore, a separate factor for S02 is presented.
-------
2-41
Table 2.4-1. Emissions From LPG Combustion, pounds per 1000 gallons
Pollutant
Aldehydes (HCHO)
Carbon Monoxide
Hydrocarbons (CH^)
Oxides of Nitrogen9
Oxides of Sulfurb
Other Organics
Parti cul ate
a) Expressed as NO,
b.) S equals sulfur
Industrial Processes Domestic and Commercial
Furnaces Furnaces
Butane Propane Butane Propane
0.70
0.14
Neg.
120
0.300S
1.76
6.3
j ,
content expr«
0.64
. 0.13
Neg.
no
0.335S
1.6
5.8
sssed in gr
Neg.
0.14
Neg.
30-100C
0.300S
Neg.
6.7
*ains per 100 CF gas
Neg.
0.12
Neg.
30-90C
0.335S
Neg.
6.1
c)
vapor, e.g., if the sulfur content is 0.16 grains per 100 CF
vapor, the S02 emission would be 0.300 (for butane) x 0.16
or 0.048 Ib S02 per 1000 gallon butane burned.
Use values of 30-50 for domestic units 50-100 for commercial units
Neg. = negligible.
Reliability of Emission Factors
While there is a lack of measured emission data from LPG combustion
in stationary sources, this fuel does have many of the characteristics
of natural gas and the emissions are therefore similar. The factors
listed in Table 2.4-1 are based on an engineering analysis of
similar processes and fuels (LPG, natural gas combustion, and fuel
oil combustion) and on measured emissions from natural gas and oil
combustion. *
-------
2-42
An overall ranking of questionable is assigned to these factors
based on the ranking in Table 2.4-2, and on the fact that the natural
gas emission data itself is about 10 years old. Los Angeles County
Air Pollution Control District sampling techniques were used. Further
work in this area is warranted due to the lack of data, and the
increased use of this fuel.
Table 2.4-2. LPG Emission Factor Ranking
Emission Data Process Data Engineering Analysis Total
0-20 0-10 0-10
28 8 18
The major assumptions made in deriving these factors were that
particulate and gaseous carbon compounds were the same as those from
natural gas combustion, and nitrogen oxide emissions were between
those for oil and gas combustion.
-------
2-43-
APPENDIX 2.4
Particulate, Carbon Monoxide, Hydrocarbons, and Aldehydes
The factors found in Table 4, Reference 4, are based upon
pounds per million cubic feet of natural gas burned. That table
was derived -from the figures given in Reference 5 which assumed
that 6000 cubic feet of gas is equivalent to one barrel of fuel oil
One barrel of fuel oil contains 312 Ib at 18,500 Btu/lb, or 5.76
x 106 Btu.5
Therefore, Duprey's emission factors are based upon
6
pounds per 960 x 10 Btu.
Using the values given in Table 2.4-3; the heating value of
LPG can be found on a gallon basis.
Table 2.4-3. Properties of
Gas
Butane
Propane
A
Avg. Gross
Btu/CF
3200
2525
B
CF/LB
6.29
8.45
Column
C
Avg. Specific
Gravi ty
2.02
1.66
D
LB/GAL
16.75
13.85
E
Btu/1000 GAL
(AxBxDxlOOO)
337 x 106
308.x 106
The emission factors shown by Duprey therefore can be converted
to relate gallonage (pounds per 1000 gallons LPG burned) by multiplying
each of Duprey's factors (excluding S02 which is treated separately
herein) as follows:
-------
2-44
GAS MULTIPLIER
Butane 337 n .,,-,
960 "
Propane 308 _
950 ~
Duprey's table is shown below, with his column for emissions
from power plants omitted:
Table 2.4-4. Emission Factors For Natural Gas Combustion
(Pounds million cubic feet of natural gas burned)
Type of Unit
Industrial Process Domestic and Commercial
Pollutant
Aldehydes .(HCHO)
Carbon Monoxide
Hydrocarbons (CH^)
Oxides of Sulfur (S02)
Other Organics
Parti cul ate
Boilers
2
0.4
Neg.
0.4
5
18
Heating Units
Neg.
0.4
Neg.
0.4
Neg.
19
Table 2.4-1 in the main text is based upon the values given in
Table 2.4-4, with each value multiplied by 0.351 and 0.321 for
butane and propane,respectively.
Sulfur Oxides
When the sulfur content, S, is expressed in grains per 100 cf of
gas fuel, the weight of S02 given off upon complete combustion of the
100 cf is:
Enole. wt. S02 1 Ib. "j
nole. wt. S7000 grains]
f x 7000I = °-000286 S 1b
-------
2-45
To determine the pounds S09 emitted from 1000 gal. of LPG,
3
find the number of 100 ft. units in 100 gallons of butane and propane.
Using the values shown in Table 2.4-3:
3
Butane: 6.29 - x 16.75 x = 1050, 100 ft.3 in 1000 gal
Propane: 8.45 x 13.85 x - = 1170, 100 ft.3 units in 1000 gal.
Thus the weight of SOp emitted from combustion of 1000 gal is:
Butane: 1050 x 0.000286 S = 0.300 S
Propane: 1170 x 0.000286 S = 0.335 S
Nitrogen Oxides
For natural gas combustion in industrial furnaces, Duprey reports
214 Ibs NO/106 ft3 or.214 per 106 Btu of fuel (1000 Btu/ft3),
6
and 72 Ibs NOY/1000 gallons of oil or 0.5 Ibs per 10 Btu of fuel
/\
(142,000 Btu/gal). An average factor for LPG assuming NO emissions
O
lie mid-way between oil and gas, would be 0.35 Ibs per 10 Btu.
For domestic and commercial units, the natural gas NOX factor
is 0.116 NOV per 106 Btu and the oil factor varies from 0.5' to 0.083 Ibs
6 6
per 10 Btu. LPG factors are therefore 0.3 to 0.1 Ibs per 10 Btu
depending on size of unit.
Butane contains 337 x 10 Btu per 1000 gals, and propane contains
308 x 106 Btu per 1000 gals. (Table 2.4-3). NOY emissions are therefore:
/\
Propane Butane
lbs/1000 gal. Ibs/lOQQ gal.
Industrial 0.35 x 308=108 0.35 x 337=118
Commercial -
Domestic 0.1 x 308=30.8 0.1 x 337= 33.7
-------
2-46
REFERENCES 2.4
1. National Petroleum News, Factbook Issue. New York, McGraw-
Hill, Inc. Mid-May 1969. p. 124.
2. Clifford, E.A. A Practical Guide to LP Gas Utilization. New York,
Moore Publishing Company, 1962.
3. North American Combustion Handbook. Cleveland, Ohio, North
American Manufacturing Company, 1965. p. 15.
4. Duprey,. R.L. Compilation of Air Pollutant Emission Factors.
National Air Pollution Control Administration, Raleigh, N.C.
Public Health Service Publication 999-AP-42, 1968. p. 6 and 7.
5. Weisburd, M.I. and S.S. Griswold (eds.). Air Pollution Control
Field Operations Manual. National Air Pollution Control Administration,
Raleigh, N.C. Public Health Service Publication 937. 1962. p. 27.
GENERAL REFERENCE
Singer, et al. Flame Characteristics Causing Air Pollution: Production
of Nitrogen. Oxides and Carbon Monoxide. Bureau of Mines. R.I. 6958.
1967.
-------
2-47
2.5 WOOD WASTE COMBUSTION IN BOILERS
General Information
Wood is no longer a primary source of heat energy as it was
before the latter part of the nineteenth century. However, there
are situations today where the availability of wood as a by-product
or waste makes it a desirable fuel for steam generation. Industries
such as lumber, furniture, plywood, and pulp, use wood in the form
of hogged chips, shavings, and sawdust as fuel. It is sometimes
burned in combination with oil, gas, or pulverized coal. This
technique is used where the available wood waste is substantial
enough to utilize, but the quantity is not always sufficient to
meet the power requirements of the plant.
Firing Practices
In general, furnaces designed for the burning of wood waste
fall into three types: 1) pile, 2) thin-bed, and 3) cyclonic. All
three of these furnaces are usually water-cooled and can be modified
to burn supplemental fuel with the wood.
In pile burning, the wood is fed through the furnace roof and
burned in a cone shaped pile on the grate. Most of the combustion
air enters under the grate around the edge of the pile. Excess air
at the boiler outlet is maintained at about 30-40%, but accurate
control is difficult.
Thin-bed burning is accomplished on a moving grate similar to
a spreader stoker. In a cyclone furnace, wood (especially bark) is
usually burned with coal.
Wood refuse from some processes contains more than 75% moisture.
Since it is not practical to burn wood with more than 60 or 65%
moisture, the excessive water is often extracted by means of mechanical
presses.
-------
2-48
Excessive water content is particularly common to pulping processes
where wood is frequently floated to the plant.
Unless the furnace is properly designed and operated, a smoke
problem will develop. The particulate matter resulting from the
combustion of hog fuel can be seen over a wide area depending on
weather conditions. In addition, gaseous emissions common to all
combustion processes will occur.
It is common practice to reinject the collected fly ash from
wood boilers. A study of 15 bark boilers indicated that each of
these had a mechanical collector which collected 80% of the fly ash
and then reinjected half of the collected portion.
Factors Affecting Emissions
Unless the furnace is properly designed and maintained,incomplete
combustion will result. The design of wood burning furnaces should
2
differ from that for coal furnaces as follows:
1. Larger area of refractory surface in the primary fuel-drying
zone
2. Higher proportion of overfire secondary air above the grate
to primary air through the grate
3. Larger combustion space, or secondary air space, to burn
the volatile matter
Excessive smoking will result from improper grate maintenance,
especially where coal is burned simultaneously with the wood. When
mixed and burned in common, the resulting ash will cause furnace
slagging and adversely affect grate performance.
Another major factor is the water content of the wood refuse.
This is not only a function of the absorptive property of the wood
but also a function of the process which produces the waste. Thus
wet bark will generally produce more emissions than kiln-dried lumber.
Of minor importance, except as it reflects on the factor noted
above, is the species of wood. Table 2.5-3. (see Appendix 2.5) shows
the ultimate analysis of various wood fuels on a dry basis. However,
-------
2-49
the composition of bark is significantly different than wood. As
shown in Table 2.5-4., bark contains less carbon and nitrogen, but
more sulfur than wood. This difference coupled with a high moisture
content is thought to account for more severe dust and smoke problems
when burning bark.
Emissions
Emissions .factors for the combustion of wood and bark in boilers
are shown in Table 2.5-1. These factors are based on the information
in Appendix 2.5.
Table 2.5-1. Emission Factors for Wood and Bark Combustion
in Boilers. Ib/ton of fuel-fired
(approximately 50% moisture content)
Emissions Conditions of Operation
no reinject. 50% reinject.8 100% reinject.3
Particulate 25-30 30-35 40-45
CO 1.5 (1 to 3)
HCC 2.0 (0.2 to 20)
N0xd 10 (6 to 15)
S02b 0-3
Carbonyls6 0.5 (0.4 to 0.9)f
a) This is not an emission factor. Value represents the loading
reaching the control equipment usually used on this type of
furnace, and is based on the percentage of fly ash reinjection
indicated.
b) Use zero for most wood and higher values for bark.
c) HC expressed as methane.
d) NOX expressed as N02-
e) As formaldehyde.
f) Trench incinerator emission (see Reference 6).
g) Particulate emissions are frequently reduced by using cyclone
collectors with efficiencies in the 75-85% range.
-------
2-50
Reliability of Emission Factors
A variety of data was used to arrive at emissions from wood
waste combustion in boilers. Particulate emissions are based on
measured data from 15 separate bark boilers and are believed to be
reliable. However, gaseous emission data are lacking and were
based on other related processes. The factor rankings are presented
in Table 2.5-2.
Table 2.5-2. Emission Factor Ranking for Wood Combustion in Boilers
Emission Data Process Data Engineering Analysis Total
0-20 0-10 0-10
Parti cul ate
Gases
15
5
5
5
5
4
25
1 14
The following assumptions were made in determining the emission
factors listed in this section:
1. Particulate emissions from wood burning is slightly less
than that for bark.
2. Gaseous emissions (CO, HC, and NOX) from wood and bark are
similar to that from the combustion of coal in industrial
boilers.
3. Carbonyls emitted from wood and bark are similar to that
from the combustion of wood in trench incinerators.
Further work on obtaining quantitative gaseous emission data
appears, justified.
-------
2-51
APPENDIX 2.5
Results of source testing of wood boilers have not been published
nor have unpublished tests results been found (with the exception of
bark boilers). Emissions from bark boilers may be substantial in
the form of particulate matter. Even some odorous gases have been
reported1, although no indication was made as to gas type and quantity.
While Hough and Gross1 reported particulate emissions of 35 pounds
per ton of pulp produced, they are not clear as to the amount of
wood burned. It is generally expected that one half ton of burn-
able wood is generated per ton of air dried pulp. On that basis,
the reported 35 pound figure might well be expressed in terms of
70 pounds per ton (based on 50% moisture content). Since that
figure is at great variance with 15 other reported figures4 and its
origin is not stated, it will not be considered.
Based on a fly ash collector efficiency of 80%, the amount of
particulate that.would be emitted from a boiler without fly ash
reinjection is about 25 to 30 pounds/ton of wood, depending on the
combustible content of the reinjected material. The process is
shown below:
Fuel
35 J/ton with 50% reinj.
Boiler
14 #/ton
at 50% reinj.
7 #/ton
Collector
E = 80%
V 28 #/ton
14 #/ton to disposal
-------
2-52
At 100% reinjection the participate entering the collector
would increase to about 40-45 #/ton of wood.
Table 2 .5-5 is a compilation of known emission data for
the burning of bark in boilers with comparable figures for
coal combustion. In the absence of data for gaseous emissions
for wood boilers the known emission figures for coal boilers
may be considered reasonably similar to that expected from the
combustion of wood.
Table 2.5-3. Ultimate Analysis of Wood Refuse Burned,
percent by weight
Carbon
Hydrogen
Sulfur
Nitrogen
Ash
Oxygen
Jack
Pine
53.4
5.9
0.0
0.1
2.0
38.6
Birch
57.4
6.7
0.0
0.3
1.8
33.8
Maple
50.4
5.9
0.0
0.5
4.1
39.1
Eastern
Hem! ock
53.6
5.8
0.0
0.2
2.5
37.9
Dry
Average
53.7
6.1
0.0
0.3
2.6
37.3
Wet
Ave rage
26.8
3.0
0.0
0.2
1.3
18.6
(by difference)
Water
50.0
Table 2.5-4. Ultimate Analysis of Wood and Bark,
percent by weight
Dry Average Wet Average
Carbon
Hydrogen
Sulfur
Nitrogen
Ash
Oxygen
Water
Wood3
53.7
6.1
0.0
0.3
2.6
37.3
-
Barkb
26.5
8.2
0.1
0.0
1.7
62.0
-
Wood3
26.8
3.0
0.0
0.2
1.3
18.6
50.0
Bark
13.2
4.1
0.05
0.0
0.8
31.0
50.0
a) See Table 2,5-3.
-------
2-53
Table 2.5-5. Comparable Emission Data for Hood,
Bark, and Coal Combustion
Fuel Type and
Equipment Type
Emissions, Ibs/ton of fuel fired0
Part. CO HCa NO b S09 Carbonyls'
Ref.
No.
Bark Boilers
Coal-fired
Industrial
Boiler-Stoker
2.3
5 Ac 1.5 1 to 6 to
2.5 15
5,7
Open Pit
Burning
4.6 to --
12.8
4
0.4 to 0.9 6
a) HC expressed as methane.
b) NO expressed as N09.
A C
c) Wood weighed on an as-fired basis of 45-50% moisture content.
d) Value represents the loading reaching the control equipment
used on this type of furnace, and is an average of 15 reported
installations. The range of emissions was 21-36 Ib/ton of
wood, based on 50* reinjection of flyash.
e) Percent ash in coal; See Reference 5.
f) Expressed as formaldehyde.
-------
2-54
REFERENCES 2.5
1. Hough, G.W., and L.J. Gross. Air Emission Control in a
Modern Pulp and Paper Mill. American Paper Industry.
36, February 1969.
2. Magill, P.L., F.R. Hoi den, and C. Ackley (eds.). Air
Pollution Handbook. New York, McGraw-Hill Book Co. 1956.
p. 1-16.
3. Fryling, G.R. (ed.). Combustion Engineering. New York,
Combustion Engineering, Inc. 1967. p. 27-3.
4. Private Communication, W.G. Tucker. Div. of Process Control
Engineering, Public Health Service, National Air Pollution
Control Administration. Cincinnati, Ohio. November 19, 1969.
5. Duprey, R.L. Compilation of Air Pollution Emission Factors, p.
National Air Pollution Control Administration. Raleigh, N.C.
Public Health Service Publication 999-AP-42. 1968. p. 4.
6. Burckle, J.O., J.A. Dorsey, and B.T. Riley. The Effects of
the Operating Variables and Refuse Types on the Emission
from a Pilot-Scale Trench Incinerator. National Air Pollution
Control Administration. (Proceedings of the 1968 Incinerator
Conference, ASME. New York. 1968.) p. 34-41.
7. Section 2.2, supra.
GENERAL REFERENCES
Reiter, F..W. Incinerator Doubles as Dutch Oven to Solve Waste-
Wood Disposal and Air Pollution Problems. Power. 102^:114-115,
January 1958.
Private Communication, D.L. Wallace. Dayton Air Pollution Control
Department. Dayton, Ohio. November 1969.
Greenfc B:.;L. Boiler for Bark Burning. Power Engineering. 52,
September 1968.
-------
2-55
Schillinger, E.S. Experience with a Large Water-Tuber Boiler
Burning Wood Waste. J. Inst. Fuel (London) 36:414, October 1963.
Steam, Its Generation and Use. New York, Babcock and Wilcox
Co., 1963. p. 19-7 to 19-9.
Kressinger, H. Combustion of Wood-Waste Fuels. Mech. Eng.
61:115-120, February 1939.
Anon. Air Pollution: How One Company Fights The Battle. Wood
and Wood Products, p. 28-29, 68, September 1968.
-------
3. REFUSE DISPOSAL
While incineration from an air pollution viewpoint is not
a recommended form of solid waste disposal, it does occur in almost
every part of the country and forms a significant part of the air
pollution problem. More than five pounds per day of solid waste
are currently collected from every person in this country, and this
value is increasing by 2-3% per year.
Approximate Particle size, microns - % by weight
Process >44 20-44 10-20 5-10 <5
Municipal Incineration 45 18 15 10 12
Atmospheric emissions, both gaseous and particulate, result
from refuse disposal operations which utilize combustion to reduce
the quantity of refuse. Many types of solid waste are currently
disposed of by a wide variety of combustion methods including both
enclosed and open burning. Emissions from these combustion processes
cover a wide range because of their dependence on the refuse burned,
the method of combustion or incineration, and the efficiency of
combustion. Many of these variables are not well controlled during
incineration. *-,
Reported factors were largely based on measured emission data.
These data were found to vary considerably. The number chosen as
the emission factor represented our best judgment based on the
available data.
-------
3-2
3.1 REFUSE INCINERATION
Process Description
Refuse incineration is the process of reducing combustible
wastes to inert residue by the use of high temperature
combustion. A wide variety of incinerators presently in
existence. Due to the variations in incinerator design, the types
of waste, and the methods of operation, incinerator emissions
vary iwidely. The most common type of incinerators consists of
a refractory lined chamber with a grate upon which refuse is
burned. This primary chamber may be followed by a secondary
combustion chamber to promote more complete combustion
of the particulate and gaseous material which is carried
over from the primary chamber. Many small size incinerators
are 5ingle chamber units which vent the gases from the primary
combustion chamber directly into the exhaust stack.
No exact definitions of incinerator size categories exist.
However, for this report the following general categories and
descriptions have been selected.
"Municipal incinerator - A multiple chamber unit with
capacities greater than 50 tons per day usually equipped
with automatic charging mechanisms and temperature
controls. Municipal incinerators are usually equipped
with some type of parti cul ate control device such as
a spray chamber.
°Industrial/commercial incinerators - These units cover
a wide size range and are generally in the 50-4000 Ibs
per hour range. They are frequently manually charged,
operate intermittently, and may be either single or
multiple chamber designs. Emission control systems
-------
3-3
among the better designs include gas-fired afterburners
and/or particulate scrubbing systems.
°Domestic incinerators - This category includes incinerators
marketed for residential use. They are fairly simple in
design (with single or multiple chamber) and usually are
equipped with an auxiliary burner to aid combustion.
°Flue-fed incinerators - These units, commonly found in
large apartment houses, are characterized by the charging
method which consists of dropping refuse down the incinerator
flue and into the combustion chamber. Modified flue-fed
incinerators utilize afterburners and draft controls to
improve combustion efficiency and reduce emissions.
°Pathological incinerators - These are incinerators used
to dispose of animal remains and other high moisture
content organic material. Generally, these units are
in a size range of 50-100 pounds per hour. They are
equipped with combustion controls and afterburners
to insure good combustion and minimum emission.
Factors Affecting Emissions
Operating conditions, refuse composition, and basic
incinerator design have a great effect on emissions. The manner
in which air is supplied to the combustion chamber or chambers
has the greatest effect on the quantity of particulate emission.
Air may be introduced from beneath the chamber, from the side
or from the top of the combustion area. As underfire air
is increased, an increase in fly ash emission is noted.
The way in which refuse is charged has a great effect on the
particulate emissions. Improper charging causes a disruption
of the combustion bed with the subsequent release of large
quantities of particulate. Emission of oxides of sulfur
-------
3-4
dependent on the sulfur content of the refuse. Nitrogen oxide
emissions depend on the temperature of the combustion gases,
residence time in the combustion zone, and the excess air rate.
Carbon monoxide and hydrocarbon emissions also depend on the
quantity of air supplied to the combustion chamber and the
efficiency of combustion.
Emissions
Table 3.1-1 lists the particulate and gaseous emission
factors for various incinerator types and classes based on
data in the Appendix. Properly operated multiple chamber
incinerators promote more complete combustion and subsequently
produce less emission than those of the simple single chamber
design. The single chamber high temperature regulated air
("starved air") incinerator is not included as a simple single
chamber design in this summary. The high temperature
incinerators employ a burner, at the base of the stack, to
achieve low particulate emission rates.
Table 3.1-2 lists the relative collection efficiencies
of various types of control equipment for incinerators. This
CShtrol equipment has little effect on gaseous pollutant emis-
sions. Table 3.1-3 lists a chemical analysis of
particulate emissions from a municipal incinerator, and Figure
3.1-1 shows the particle size distribution of particulate
11 1 ?
emissions from a municipal incinerator. s "
-------
Table 3.1-1. Emission Factors for Refuse Incineration
Incinerator Type
Emissions, Ibs/ton of refuse charged
Parti oil ate
SO..
HC
NO.
CO
Municipal
Multiple Chamber
Uncontrolled 30(3 to 35)
With Settling Chamber 17d(2.6 to 20)
& baffled water spray
system
1.5 (1 to 1.8) 1.5 (0.1 to 1.8) 2 (0.1 to 3.3) 0.8 (0.3 to 4)
(Gaseous emissions same as above)
Indus tri al /Commerci al
Multiple Chamber 5(3 to 6)d 1.5e
Single Chamber 15(4 to 31) 1.5e
Flue Fed 30(7 to 76) 0.5
Flue Fed (Modified)1 6(1 to 10.2) 0.5
Domestic Single Chamber
Without primary burner 35 0.5
With primary burner 7 0.5
Pathological 5(2.3 to 8) neg.
a) Expressed as S02.
b) Expressed as methane.
c) Expressed as N02<
d' Cyclones and scrubbers can reduce
this factor by 70-80%.
3(0.3 to 20) 3 (2.5 to 3.5)
15(0.5 to 50) 2 (0.1 to 2)
15(2.2 to 40). 3 (1.3-6)
39 10(7-16)
100 2f
2 2
neg. 3(1.2-8.8)
e) Based on municipal incinerator.
f) Based on single chamber commercial
10 (1 to
20 (4 to
20f
negh
300
neg.h
neg.
25)
200)
incinerator.
g) Estimated factor, based on commercial units.
h) Neg. = negligible.
i) With afterburner and draft controls
.
co
en
Note: Use high side of particulate, HC, and CO emission range when operation is
intermittent, and combustion conditions are not good.
-------
3-6
Table 3.1^2. Participate Control Efficiencies of Various Types
of Control Equipment Applied to Municipal Incinerators
System Type Efficiency, %
Settling Chamber 0 to 30
Settling Chamber and Water Spray 30 to 60
Mechanical Collector 30 to 80
Scrubber 80 to 95
Electrostatic Precipitator 90 to 96
Fabric filter 97 to 99
a) Based on Reference 1.
Table '$.1-3. Chemical Analysis of Fly Ash Samples From Typical
Municipal Incinerator
Component Percent of Particulate Emitted
Organi'c 10.4
Inorganic 89.6
Silica as Si02 , 36.1
Iron as Fe20 4.2
Alumina as A1203 22.4
Cal'C'tum as CaO 8.6
Magnesium as MgO 2.1
Sulfur as S03 7.6
Sodtum and potassium oxichs 19.0
-------
OJ
I
.01
10 - 50 90
% BY WEIGHT LESS THAN STATED SIZE
9999
Figure 3.1-1 Porticulate particle size distribution from municipal incinerators
-------
3-8
Reliability of Emission Factors
Emission factors for participates from multiple chamber
municipal incinerators was largely based on data obtained
by various Bureaus of the Public Health Service. The sampling
techniques are set forth in "Specifications for Incinerator
Testing at Federal Facilities".
Substantial particulate emission data on small sized
incinerators was obtained from Resources Research, inc. (RRI),
source sampling information and from literature sources.
Most of the RRI data was obtained using the PHS procedures
or a modification of these procedures.
Gaseous emission data were not as readily available as
particulate emission data. Considerable variation was found
due to the difference in incinerator operation.
The emission factor information in this section incor-
porates much previously unpublished information obtained
from RRI's source tests and various Bureaus of the Public
Health Service. RRI data, PHS data and Los Angeles County
data have been considered as more reliable than other data
found.
-------
3-9
Table 3.1-4. Emission Factor Ranking for Incinerators
Municipal Incinerators
Parti cul ate
Gases
Commercial/ Indus trial
Parti cul ate
Gases
Domestic
Parti cul ate
Gases
Flue Fed
Parti cul ate
Gases
Pathological
Parti cul ate
Gases
Emission
Data
0-20
15
8
15
8
5
5
15
3
10
8 '
Process
Data
0-10
8
8
5
5
5
5
5
5
5
5
Engineering Total
Analysis
0-10
5
5
5
5
3
3
5
5
8
8
28
21
25
18
13
13
25
13
23
21
Table 3.1-4 indicates that most of the particulate emission
i
factors are considered good, while most of the gaseous factors
are considered questionable.
No major assumptions were made in obtaining these data
since they are mainly based on actual emission measurements.
-------
3-10
Table 3.1-5.
APPENDIX 3.1
Emissions from Municipal Multiple Chamber
Incinerators, Ibs/ton of Refuse Charged
Paniculate S0..a HCb
A
35
8.1 <0.08
18d 1
9 1.8 0.34
12.4 1.8
25.1
9-1
30.8
11.8
20.4*
14.56
17.2-
13.6e
3 1.0
2.6e
T7*'-e' or 30 1.5 1.5
(2.6-20): (3-35) (1.0- 1.8) (0.1-1
N0..c
X
2.4
2.5
2.4
1.4-3.3
0,8
2.3
3.1
1.2
2.8
0.1
3.0
2
.8)(0.1-3.3)
a) S0v expressed as S09.
X i-
b) Hydrocarbons expressed as methane.
When the referenced data was reported
as hexane, it was converted to
methane by multiplying by 96/86.
CO Reference
1
4 2
0.67 2
0.3 3
0.7 4
4
4
4
4
5
5
5
5
5
6
7
7
7
7
7
8
2
0.8 Factor
(0.3-4) Range
c) NO expressed as N0?.
A t.
d) After settling chamber.
e) After water spray system
-------
3-11
Table 3.1-6. Emissions from Industrial and Commercial Multiple
Chamber, Incinerators, Ibs/ton of Refuse Charged
Parti cul ate
6.2 c
3.7
3.4
4.7d
4.6d
4.8d
4.2d
3.5
HCa
3.6
0.28
16(6 to 20)
le
0.3
N0vb CO
X
25
0.05
3.5 7(4 to 9)
2.5 2.9
Reference
2
3
3
4
9
9
9
.9
5
8
5 (with water
sprays)
3.4-6.2
0.3-20
2.5-3.5
10
0.05-25
Factor
Range
a) HC expressed as methane.
b) NO expressed as N09.
X L.
c) With auxiliary burner fn
primary chamber.
d) With low efficiency scrubber
or spray system, average of
three tests.
e) Originally reported by
Williamson as <1 expressed
as hexane.
Table 3.1-7.
Particulate
Emissions from Industrial and Commercial Single Chamber
Incinerators, Ibs/ton of Refuse Charged
HC9
NO.
CO
Reference
4.1C
31 .0
23.8
6.3d
6.9d
14. 2d
15
4.1-31.0
0.45
20-50
8
19
9
15
0.45-50
1.6
0.1
2
2
2
2
0.1-2
4.3
84
197-991
5.6(2 to 8)
2.5
8
20
4.3-991
2
3
4
5
9
9
9
Factor
Range
a) HC expressed as methane.
b) NOX expressed as N02.
c) No underfire air.
d) With water sprays.
-------
3-12
Table 3.1-8.
Emissions from Flue Fed Incinerators,
Ibs/ton of Refuse Charged.
Parti cul ate S0va HCb
X
40
0.5
76 2.2
52
48
37
37
34
25
23,
23,
19
17
7
26.2 0.5
13.4
3.9
IT. 7( with scrubber)
14.5(with scrubber)
33(no scrubber) 0.5 14
7-76 2.2-40
a) SO expressed as S0«.
X £
b) HC expressed as methane.
c) NO expressed as N0?.
NO c Reference
/\
1.3-4.4 4
8
6 5
5
5
5
5
5
5
5
5
5
5
5
0.07 6
10
10
9
9
2.9 Average
1.3-6 Range Used
-------
3-13
Table 3.1-9. Emissions from Modified Flue Fed Incinerators ,
Ibs/ton of Refuse Charged
Parti cul ate SOYa
A
6.1 0.5
6.5
5.9
5.2
5.6 ,
1.2
10.2
5.9(1 .3 after water
spray)
5.3
6 0.5.
1.2 to 10.2
HCb NOVC
A
16
4.2
7
-
0.14
3d 10
7 to 16
CO Reference
5
5
5
5
5
5
6
9
9
Factor
Range
a) SO expressed as S09.
A ' £
b) HC expressed as methane.
c) NO expressed-as N09. "
X £
d) Estimate based on commercial
units.
-,'..-e) Chute fed unit, average of 3 tests.
f) With afterburners and draft
controls.
Table 3.1-10. Emissions from Domestic Incinerators (Without Gas-Fired
Primary Burner), Ibs/ton of Refuse Charged.
Parti cul ate
39
soa
X
0.4
HCb
100
100
NO C CO
X
7d 300
300-600
Reference
3
4
a) SOX expressed as
b) HC expressed as methane.
c) NOX expressed as NOp
d) Final factor was based on single chamber incinerator,
-------
Table 3.1-11.
3-14
Emissions from Domestic Incinerators (With Gas
Afterburner), Ibs/ton of Refuse Charged
Parti cul ate
6.3
soxa
0.4
HCb
1.5
NOVC CO
A
2.0
Reference
3
a) SO expressed as SO,,.
X £
b) HC expressed as methane.
c) NO expressed as NO,,
y\ Cm
Table 3.1-12. Emissions from Pathological Incinerators, Ibs/ton
of Refuse Charged
Parti cul ate
2.3
8.0
3.1
7.3
5
2.3-8.0
HCa
neg.
neg.
neg.
neg.
neg.
NOYb
X
1.2
1.6
8.8
2.0
3
1.2-8.8
Reference
5
5
5
5
Factor
Range
a) HC expressed as methane.
b) NO expressed as NO,,.
J\ £
-------
3-15
REFERENCES 3.1
1. Fernandes, J.H. Incinerator Air Pollution Control. In:
Proceedings of 1968 National Incinerator Conference.
New York. American Society of Mechanical Engineers.
May 1968. p. 111.
2. Hangebrauck, R.P., et al. Emissions of Polyrtuclear Hydro-
carbons and other Pollutants from Heat Generation and
Incineration Processes. Air Pollution Control Association.
14; 275, July 1964.
3. Kanter, C.V., R. G. Lunche, and A. P. Fudurich. Techniques
for Testing for Air Contaminants from Combustion Sources.
J. of Air Pollution Control Association. j5 (4) :191-199,
February 1957.
4. Unpublished Report on Incineration. National Air Pollution
Control Administration. Office of Technical Information and
Publications, Raleigh, N. C. 1969.
5. Williamson, J. Incineration. In: Air Pollution Engineering
Manuel, Danielson, J. (ed.). National Air Pollution Control
'Association. Raleigh, N. C. Public Health Service
Publication 999--AP-40. 1967. p. 413-435 and 447-470.
6. Kaiser, E. R., et. al. Modifications to Reduce Emissions
from a Flue Fed Incinerator. N. Y. University, College of
Engineering. Report 552.2. June 1959. p. 40 and 49.
7. Unpublished Data. Public Health Service, Bureau of Solid
Waste Management, Technical Assistance Division, Cincinnati,
Ohio. 1969.
8. Kaiser, E. R. "Refuse Reduction Processes in Proceeding of
Surgeon General's Conference on Solid Waste Management.
Washington, D. C. Public Health Service #1729. July 10-20, 1967.
-------
3-16
9. Resources Research, Inc. Source Test Data. 1966-1969.
10. Communication with State of Maryland, Division of /h'r
Quality Control ,1969.
11. Proceedings of the 1964 National Incinerator Conference.
American Society of Mechanical Engineers. New York.
May 1964. p. 17 and 124.
12. Proceedings of the 1966 National Incinerator Conference.
American Society of Mechanical Engineers. New York.
May 1966. p. 71, 81, 163.
GENERAL REFERENCES
Robinson, E. and R. C. Robbins. Sources, Abundance, and Fate
of Gaseous Atmospheric Pollutants. Stanford Research Institute,
February 1968.
Rehtn, F. R. Incinerator Testing and Test Results. J. Air
Pollution Control Assoc. i(4); 199-204, February 1957.
Jacobs, M. B. Performance of a Flue Fed Incinerator. 0. Air
Pollution Control Assoc. 9_(2):85-91, 1958.
Stenburg, R. L., et al. Effects of Volatile Fuel on Incinerator
Effluents. Journal of Air Pollution Control Association. 11:
376-583, August 1961.
Altman, P. L. Environmental Biology. Aerospace Medical Research
Labs, Wright-Patterson ABF. Dayton.
Fife, J. A. Controlled Combustion for Solid Waste Disposal.
Heating, Piping, and Air Conditioning. March 1968. p. 146.
-------
3-17
3.2 AUTOMOBILE BOB^'MCINERATION
Process Description
Approximately 10 million automobiles are scrapped each year in
the United States, and the accumulation'and eventual disposal of
these discarded bodies presents an increasing problem in urban areas.
For many years open burning of automobile bodies to prepare them for use in
the steel industry has been practiced, -.but the heavy black smoke
resulting from this practice has led to-^regulations banning this form
of open burning in many areas.
However, burning is still a practical way to prepare scrapped cars
for steel processing if the air pollution problems resulting from the
incomplete combustion of paint, upholstery, insulation, floor mats, hoses,
etc., can be solved. In an attempt to reduce the various air pollutants
produced by this burning, automobile incinerators have been developed which
are equipped with emission control devices. Both afterburners and/or
low voltage electrostatic precipitators have been used to reduce
2 3
particulate emissions ' , with the former also reducing some of the
gaseous emissions. Afterburner particulate removal efficiencies of
3
about 40% have been reported.
Automobile incinerators consist of a primary combustion chamber into
which the'partially stripped car(s) is placed. The car is then ignited, and
the incinerator doors are closed. Approximately 30-40 minutes are
4
required to burn two bodies simultaneously. Up to 50 cars per day
can be burned in this batch type operation depending on the size of the
incinerator, that is, the number of cars burned simultaneously. Continuous
operations in which cars are placed on a conveyor belt and passed through
a tunnel type of incinerator have capacities of more than 50 cars
per 8 hour day.
Factors Affecting Emissions
Both the degree of combustion as determined by the incinerator design,
and the amount of combustible material left on the car greatly affect combustion.
-------
3-18.
Temperatures on the order of 1200°F'are reached during automobile body
a
incineration. This relatively low combustion temperature is caused
by the large incinerator volume needed to contain the bodies as
compared to the small quantity of combustible material. The use of
overfire air jets in the primary combustion chamber will increase
combustion efficiency by providing air and increased turbulence.
Normally tires are removed from the cars before incineration.
Incineration with tires would tend to increase the particulate emissions
When afterburners are used to control emissions,, the temperature
in the secondary combustion chamber should be at least 1500°F. Lower
temperatures will result in higher emissions.
Emissions
Particulates in the form of smokes aldehydes, hydrocarbons,
organic acids, and nitrogen oxides are emitted from the combustion
of junked automobiles. Particulate is composed of approximately
67% combustible matter, largely carbon.^
Table 3.2-1 presents a summary of emission data reported in the
literature. More detailed data and related calculations are provided
in the Appendix 3.2.
Table 3.2.-1. Emissions from Automobile Body Incineration,
Ibs/Car Burned
Particulates
CO
HC (as methane)
Aldehydes (as HCOH)
Organic Acids (as Acetic)
Nitrogen Oxides (as N02)
Uncontrolled
2 (1.6 - 2.1)
2.5 (2 - 3)
0.5 (0.3 - 0.7)
0.1 (0 - 0.2)
0.2 (0 - 0.4)
0.3 (0.2 - 0.4)
With Afterburner
1.5 (1 - 1.9)
negligible
negligible
0.02
0.06
0.4
-------
3-19
Reliability of Emission Factor
Limited emission testing has been done on automobile body incinera-
tion. However, the reported data agree fairly well considering the
process variables inherent in any type of incineration.
Table 3.2-2 presents, the factor ranking.
Table 3.2-2. Automobile-Body Incineration Emission Ranking
Emission
Data
0-20
Process
Data
0-10
Engineering Tota'
Analysis
0-10
10 5 5 20
The trend toward automobile shredders and pulverizers will probably
reduce the amount of automobile body incineration in the future. Further
work in this area does not appear warranted.
The only major assumption made in obtaining these factors was that
CO and hydrocarbon emissions approximated one-sixth of the factors
obtained in open burning of automobile components.
-------
3-20
APPENDIX 3.2
Emission Data Calculations
A. Participate
Uncontrolled - burning 3 cars per hour (Ref. 3)
1. 0.63 grs/ft3 at 12% C02 x 4% C02 x 3500 ft3 x 60 min x 1 Ib = 6.3 Ibs/hr
12%~CO^ m1n hr 700° gr
2. At 0.45 grs/ft3 x 4.5% C02 x 3500 x 60 x 1 = 5.1 Ibs/hr
TZ7000 Avg. = 5.7 Ibs/hr or
u 1.9 Ibs/car
Controlled - with gas-fired afterburners - 3 cars/hour (Ref. 3)
1. 0.26 grs/ft3 at 12% C02 x 5.5% x 3400 ft3 x 60 x 1 =3.5 Ibs/hr or
12 min 7000 1.2 Ibs/car
2. 0.16 x 6^3 x 3200 x 60 x 1 = 2.3 Ibs/hr
12 7000 Avg. = 2.9 Ibs/hr or 1 Ib/car
Controlled with oil-fired afterburner, 3 /2 cars/hour
0.27 x 7.3 x 4200 x 60 x 1 =5.9 Ibs/hour
12 7000
At 3/2 cars/hour, emissions = 1.7 Ibs/car
Controlled with afterburner - 4 cars/hour (Ref. 4, pg. 70 and 71.)
2170 ft/min x * x 392 x 60 min x 520°R x 29 Ib/lb mol x 0.357 Ib
4 x 144 hr 1960°R 379 ft3/mol 1000 Ib gas
= 7.84 Ibs/hour
B. Gaseous Emissions (Ref. 3) - 3 cars/hour burning rate = 1>9 lbs/car
NOX as N02
Uncontrolled
Avg. = 32 ppm - 25%
32 x 10~6 x 3500 ft x 60 min x 46 Ibs/lb-mol = 0.815 Ib N02/hour or
min hour 379 ft3/lb-mol 0.27 lbs/car
With gas-fired afterburner
Avg. = 46.5 ppm
3J
min 379 0.4 lbs/car
46.5 x 10"5 x 3300 ft3 x 60 x 46 = 1.2 Ibs N02/hour or
-------
3-21
Aldehydes as HCOH (formaldehyde)
Uncontrolled - 16 ppm
16 x 10-6X 35SO_ft jrnn 30 Ibs/lb-mol =
mm
hour 379 ft-vlb-mol o.l Ibs/car
With gas-fired afterburner - 3 ppm
Emission = 0.05 lbs/hour pr 0.02 Ibs/car
Estimated range for aldehyde emission was assumed t 100%.
Organic Acids^
Uncontrolled 0.62 lbs/hour - 0.2 Ibs/car (t 100% estimated)
With gas-fired afterburner 0.2 lbs/hour = 0.06 Ibs/car
CO and Hydrocarbons
Open burning emissions (Reference 5) which are reported on a 1 fas/ton
automobile components, and the fact that there are about 250 Ibs of
combustible material on a stripped car body (one without tires)^ yields
the following emission rates.
250
Open burning data, Ibs/ton x WT = Ibs/car body
IBS/TON5'6 IBS/ CAR
Particulate 100 12.5
NOY 2-5 0.25 - 0.62
/\
Formaldehyde 0.03 0.38
CO 125 15
HC (as methane) 30 3.7
It is seen that uncontrolled emissions of parti cul ate and
formaldehyde from automobile incineration are approximately 1/6 to 1/4
of the open burning values. An estimate of CO and gaseous hydrocarbons
based on 1/6 of the open burning values should give some idea of the
incineration emission. These values are 2.5 Ibs CO per car and 0.5 Ib.
HC per car.
-------
3-22
REFERENCES 3.2
1. Anon, Car Junkyards Try Sophistication. Business Week,
February 26, 1966. p. 108-112.
2. Alpiser, F.M. Air Pollution From Disposal of Junked Autos. Air
Engineering. TjO:18-22, November 1968.
3. Walters, D.F. Memorandum - Summary of Tests on Auto Body Burner.
National Air Pollution Control Administration, July 19, 1963.
In: Air Pollution from Disposal of Junk Autos by F.M. Alpiser
Air Engineering. JJh 18-22, November 1968.
4. Kaiser, E.R., and J. Tolcias. Smokeless Burning of Automobile
Bodies. J. Air Pollution Control Association. 1_2:64-73, February 1962.
5. Gerstle, R.W., and D.A. Kemnitz. Atmospheric Emissions from Open
Burning. J. Air Pollution Control Association. 17^324-327, May 1967.
6. Infra, 3.4.
-------
3-23
3.3 MUNICIPAL REFUSE AND WOOD DISPOSAL IN CONICAL BURNERS
Process Description
Conical burners .are generally a truncated sheet metal cone with a
screened top vent. The charge is placed on a raised grate by conveyor or
bulldozer, the former method resulting in more efficient burning. No
supplemental fuel is used but limited control of combustion air is often
effected by means of a blower which supplies underfire air below the
grate and peripheral openings in the shell which provide overfire air.
For best results, each of these supply air systems is designed to
create a cyclonic action. Excessive combustion air prevents good
control of the combustion process and results in excessive smoke and other
air contaminants.
The cylindrical or silo incinerator consists of a steel silo lined
with refractory materials. Air is admitted through openings near the base of
the incinerator. It is generally held that more efficient combustion can
be attained in a cylindrical incinerator since the refractory-lined chamber
maintains higher operating temperatures than the standard conical burner.
However, emission test data does not indicate any significant reduction in
contaminants emitted and, for the purpose of this study.no distinction
is made between these two types of incinerators.
Factors Affecting Emissions
Many factors affect combustion within conical and cylindrical type
incinerators. -Quantity and types of pollutants are dependent on the makeup
and moisture content of the charged material, control of combustion air,
type of charging system used, and the condition in which the incinerator
is maintained. It is difficult to establish what effect each of these
factors has on the emission of contaminants. The most critical single
factor seems to be the lack of maintenance on the incinerators. It is not
-------
3-24
uncommon for conical incinerators to have doors missing and a multiplicity
of holes in the shell, all resulting in excessive combustion air, low
temperatures, and therefore high emission rates.
Particulate control systems have been adapted to conical burners
with some success. These control systems include water curtains (wet
caps) and water scrubbers.
Emissions
Published emission data for waste combustion in conical burners
are very limited. Regarding municipal waste, some particulate data were
available, but gaseous emission factors were estimated based on open
burning and incineration test data. Detailed emission data are presented
in the Appendix and summarized in Table 3.3-1.
Table 3.3-1. Emission Factors for Waste Incineration in Conical and
Type of Waste
Cylindrical Burners
Emissions, Ib/ton of waste as firedc
Municipal Refuse
Wood
Particulate CO
30 (10 to 60) 60
la
10b
20C
130(30
to 360)
HCe
20
10(0.8
to 43)
NO f
5
1.2
SO,
L.
3
0.15
a) Properly maintained burner with adjustable underfire air supply and
adjustable, tangential overfire air inlets; approximately 500% excess
air and 700°F exit gas temperature.
b) Properly maintained burner with radial overfire air supply near bottom
of shell; approximately 1200% excess air and 400°F exit gas temperature.
c) Improperly maintained burner with radial overfire air supply near
bottom of shell and many gaping holes in shell; approximately 1500%
excess air and 400°F exit gas temperature.
d) Moisture content as-fired is approximately 50% for wood waste.
e) HC expressed as methane.
f) Expressed as NO^.
Note: Use high side of range for intermittent operations charged with
a bulldozer.
-------
3-25
Reliability of Emission Factors
-1 '
'^- Particulate emission factors for combustion of municipal refuse
or wood waste in conical burners are good even though they cover a
range of values. However, gaseous emission data are very scarce and
difficult to estimate. Emission factor rankings are presented in
Table 3.3-2.
Table 3.3-2. Emission Factor Ranking for Conical Burners
Particulate
Gases
Emission Data
0-20
14
7
Process Data
0-10
5
5
Engineering Analysis
0-10
5
3
Total
24
15
No major assumptions were made in obtaining the factors presented
in this section, except that inferences were drawn from incineration
emission data to determine gaseous emissions from conical burners.
-------
3-26
APPENDIX 3.3
Municipal Waste
There are no published results of incineration of municipal waste
in conical or cylindrical burners. The results of one unpublished test
for particulate emissions made on a conical burner by the Bureau of
Solid Waste Management2 are shown in Table 3.3-3. Note that there
is no correlation between the rate of feed and the particulate emissions.
For instance, while the feed rate of test No. 1 was 50% greater than test
No. 4, the emissions were substantially less. Comparing tests 4, 5, and 6,
we find there is no correlation. Since all tests were made under iden-
tical conditions on the same burner it can only be concluded that the
particulate emissions are greatly affected by the composition of the
charged material. Due to the limited sample size, a statistical evalua-
tion of the data has not been made. Under the circumstances, it seems
more reasonable to assign a range (10-60) to the particulate emission
factor.
Table 3.3-3. Particulate Emissions From a Pilot Scale
Test No.
1
2
3
4
5
6.
Conical
Feed Rate,
Ibs/hr
1670
1670
1460
1190
1190
1190
Burner
Ib/hr
8.65
8.70
13.26
32.44
17.46
4.41
Particulate
Ib/ton
10.3
10.5
18.2
54.6
29.4
7.4
Emission,
% of feed
0.5
0.5
0.9
2.7
1.5
0.4
Values for gaseous emissions must be approximated from the values
found for. other types of incinerators. These values are shown in
-------
3-27
table 3:3-4. Incineration in conical and cylindrical burners tends
to resemble open burning in that the fire must support itself, no
auxiliary fuel being used. Unlike open burning, however, outside
wind conditions do not appreciably affect the combustion and the
combustion air supply can be regulated. The ambient temperature is
a factor since the metal skin has no significant insulation value.
Except for size, the backyard incinerators are seemingly most similar
to the conical burners, but the data from Reference No. 6, shown in
Table 3.3-4, are so high, relatively speaking, as to preclude full
consideration. More complete combustion may generally be expected
from flue fed and single chamber incinerators since they control
the overfire and underfire air rates to a greater extent.
Analyzing the abovej it must be concluded that the incineration
of municipal Waste in conical and cylindrical burners is more efficient
than open burning and less efficient than single chamber incinerators.
Table 3.3-4. Gaseous Emissions From Municipal
Waste
Type of Incineration
! ,
Incineration
Emissions,
S00 CO
t.
Open Burning and Single Chamber 3 40
Open Burning
Single-Chamber (Commercial)
Backyard Incinerator
85
1.5 20
600
Ib/ton
HCa
8
30
15
115C
of waste
N0..b
X
4
4-9
2
1
Reference
Number
3
4
5
6
a) HC expressed as methane.
b) NO expressed as N0~.
A, £
c) Reported values for saturated HC (30) and methane (85) were assumed
to be expressed as methane.
-------
3-28
Wood Waste
Very little testing has been done to measure emissions from
the incineration of wood waste in conical and cylindrical burners.
Almost all the reported figures are confined to particulate emissions.
Table 3.3-5 compares the available test data with the open burning
4
figures developed by Gerstle and Kemnitz.
There is no correlation between the particulate emission figures
which range from 1 to 20 Ib/ton of wood waste. The highest figure
was obtained from a conical burner having radial air openings and
many gaping holes all over the shell. The exit gas temperature
averaged about 400°F with approximately 1500% excess air while the
burner which emitted only 2 Ib. particulate matter/ton of wood
waste, averaged approximately 700°F exit gas temperature with 500%
excess air. Thus three particulate emission factors are given fn
Table 3.3-1 based on the condition and operation of the equipment.
Table 3.3-5. Emissions From Wood Waste Incineration
Type of Incineration
Emissions, Ib/ton of waste as-fired Reference
Open Burning
Cylindrical (Silo)
Cylindrical (Silo)
Conical - Satisfactory Operation
Conical - Unsatisfactory
Conical - Very Unsatisfactory
Cylindrical (Silo)
Conical
Conical
17
20
2
D.2-2.
7.3
20.2
12
10.7(0
19.9)
£.-
0.15
0.16
J
.2-
50
130(30
-360)
3
20
11(0.,!
-43)
A
1
1.3
1.2
J
4
7
8
9
9
9
10
11
12
a) Hydrocarbons expressed as methane.
b) Moisture content as-fired is approximately 50%.
-------
3-29
Carbon monoxide emissions from conical burners have been
measured by Droege and Lee. These measurements are the basis for
carbon monoxide emission factors. The emission factors for hydro-
o
carbon and oxides of nitrogen are based on measured data.
-------
3-30
REFERENCES 3.3
1. Kreichelt, I.E. Air Pollution Aspects of Teepee Burners.
National Air Pollution Control Administration. Raleigh, N.C.
Public Health Service Publication 999-AP-28. September 1966.
2. Private Communication with Public Health Service, Bureau of
Solid Waste Management, Cincinnati, Ohio. October 31, 1969.
3. Weisburd, M.I., and S.S. Griswold (eds.). Air Pollution Control
Field Operations Manual. National Air Pollution Control
Administration. Raleigh, N.C. Public Health Service Publication
937. 1962. p. 29.
4. Section 3.4, infra.
5. Section 3.1, supra.
6. Feldstein, M., et al. The Contribution of the Open Burning of
Land Clearing Debris to Air Pollution. J. Air Pollution Control
Association. 13:542-545, November 1963.
7. Magill, P.L., and R.W. Benoliel. Air Pollution in Los Angeles
County, Contribution of Combustion Products. Industrial and
Engineering Chemistry. 44:1347, June 1952.
8. Anderson, D.M., J. Lieben, and V:H. Sussman. Pure Air for
Pennsylvania. Pennsylvania Department of Health. Harrisburg, .Pa.
November 1961. p. 98.
9. Boubel, R.W., et al. Wood Waste Disposal and Utilization.
Engineering Experiment Station, Oregon State University. Corvallis,
Oregon. Bulletin No. 39. June 1958. p. 57.
10. Netzley, A.B., and J.E. Williamson. Multiple Chamber Incineratprs
for Burning Wood Waste. In: Air Pollution Engineering Manual,
Danielson, J.A. (edo)« National Air Pollution Control Administration.
Raleigh, N.C. Public Health Service Publication 999-AP-40. 1967.
p. 436.
11. Droege, H.s and G. Lee. The Use of Gas Sampling and Analysis
for the Evaluation of Tepee Burners. Bureau of Air Sanitation,
-------
3-31
California Department of Public Health (Presented at the
Seventh Conference on Methods in Air Pollution Studies. Los
Angele's. January 25 and 26, 1965.) 7 pages.
12. Boubel, R.W. Particulate Emissions from Sawmill Waste Burners.
Engineering Experiment Station, Oregon State University.
Corval.lis, Oregon. Bulle.tin No. 42. August 1968. p. 7 and 8.
-------
3-32
3.4 OPEN BURNING
General Information
Open burning can be carried out in open drums or baskets and in
large scale open dumps or pits. Materials commonly disposed of in
this manner are municipal waste, automobile body components, landscape
refuse, agricultural field refuse, wood refuse, and bulky industrial
waste.
While open burning of waste is not desirable from an air pollution
point of view, exemptions from control are often applied to right-of-
way clearing, field burning of agricultural wastes, logging debris
and bulky materials, since it is frequently the cheapest method for
disposing of such refuse.
Disposal of agricultural wastes is imperative because the refuse
piles act as reservoirs of horticultural diseases and agricultural
pests. As agricultural activities grow more intensive, the danger
of horticultural debris carrying diseases and pests to succeeding
crops increases. Thus, until a non-chemical means of disease control
can be found, open burning of residues will continue to be common
practice.
A similar problem exists regarding lumbering activities. On the
average, 25 million tons of logging debris are left in the woods each
year. As with horticultural wastes, this debris harbors tree diseases
and harmful insects and, in addition, poses an exceedingly serious
fire hazard. It has been reported that the average size of forest
fires originating in logging waste is more than seven times the
average size of fires originating in uncut areas.
-------
3-33
Factors Affecting Emissions
Ground level, open burning is affected by many variables
including wind, ambient temperature, moisture content of the debris
burned, size and shape of the debris, and compactness of the pile.
To what degree each of these variables affects the burning is not
known. Additional research is required in this area if refinement
of the emission factors is desired.
In general, the relatively low temperatures associated with open
burning increase the emissions of particulate, carbon monoxide, and
hydrocarbons, while suppressing the emission of nitrogen oxides and
sulfur oxides. The sulfur oxides are also a direct function of the
sulfur content of the refuse.
Emissions
Emission factors are presented for the open burning of three
broad categories: 1) municipal refuse, 2) automobile components,
and 3) horticultural refuse. The factors are listed in Table 3.4-1.
See Appendix 3.4 for a discussion of these factors.
Table 3.4-1. Emission Factors for Open Burning
Type of Waste Emissions, Ib/ton of waste as fired
Particulate CO HCa NO b S09
A £m
Municipal Refuse 15 (14 to 59) 85 (80 to 90) 30 6 (4 to 9) 1
Automobile Components0 100 125 30 4 (2 to 5) neg.
Horticultural Eefuse
1) Agricultural 17 (12 to 23) 100 (36 to 175) 20 (3 to 50) 1 to 4 neg.
Field Burning
2) Landscape 17 (12 to 23) 60 (45 to 87) 20 (5 to 35) 1 to 4 neg.
Refuse and
Pruning
3) Wood 17 (12 to 23) 50 4 1 to 4 neg.
-------
3-34
Table 3.4-1. Continued
a) HC expressed as methane.
b) NO expressed as N0?.
/\ t
c) Upholstery, belts, hoses, and tires burned in-common.
Reliability of Emission Factors
The factors for open burning are limited by the fact that
accurate source testing on large scale burning dumps is extremely
difficult. Factors thus must be based on simulated open burns carried
out under controlled conditions in the laboratory or on information
collected at actual open burns which is subject to considerable
variation. The documented laboratory studies plus actual testing
do however give information which is fairly complete and should
serve to categorize the emissions from open burning within satisfactory
limits. The factors here are thus considered to be good and no
further work is indicated,except a more detailed analysis of gaseous
hydrocarbon emissions is warranted. Emission factor rankings are
presented in Table 3.4-2.
Table 3.4-2. Emission Factor Ranking for Open Burning
Emission Data Process Data Engineering Analysis Total
0-20 0-10 0-10
10 8 6 24
No major assumptions were made in obtaining the factors presented
in this section except that the determination of SOp emissions from
the open burning of municipal refuse was based on information obtained
from incinerator emissions.
-------
3-35
APPENDIX 3.4
Little testing has been done regarding the open burning of
municipal waste. Table 3.4-3 compiles all the figures found in the
literature for such burning. In general, the average figures reported
2
by Gerstle and Kemnitz are adopted as emission factors since none of
the other reported numbers is based on actual testing of open burns.
The figures reported by Feldstein, et al are at such great variance
with the other figures that little or no weight has been given them.
Since the open burn test data for municipal refuse does not include
sulfur oxides, and the reported estimated figures (See Table 3.4-3.)
do not agree with incineration test data, a comparative analysis is
warranted. The formation of sulfur oxides is dependent on two
factors: 1) sulfur content of refuse and 2) efficiency of the
combustion operation. The sulfur content of municipal waste is,
generally speaking, constant. Open burning differs from multiple
chamber incineration only as. regards efficiency of combustion.
Less sulfur is oxidized in the less efficient open burn. Thus the
sulfur oxides emitted from open burning must be less than that emitted
from incinerators. Incinerators emit approximately 1.5 Ib/ton
(see Section 3.1 supra.). Estimating an open burn combustion efficiency
of 60-70% relative to multiple chamber incineration, it is expected
that the former operation will emit 1.0 Ib/ton of sulfur oxides. This
figure is between the 3.0 and 0.3 reported in Table 3.4-3.
Only one data source has been found for emissions from the open
burning of automobile components These figures are shown in Table 3.4-4.
Table 3.4-5 lists all the reported data for emissions from
open burning of horticultural wastes.
-------
3-36
There are no reported particulate emission figures for the open
burning of pure.ly wood wastes. The data reported for hydrocarbon and
carbon monoxide emissions are for fruit tree primings and do hot
directly relate to wood wastes due to lumbering and saw mill activities,
The composition of the fruit prunings necessarily included small
branches, leaves, and twigs.
Only one study has expressed nitrogen oxide emissions in terms
2
of pounds per ton of material burned. Even these readings are not
conclusive, as they are instantaneous determinations of a rate. The
reported figure is low since, in open burning, temperatures are
generally relatively low. The temperature of the test fires reached
its peak at approximately four minutes after burning was started and
then diminished at a rapid rate. Thus the high-intensity burning
required for the oxidation of atmospheric nitrogen exists only for
2
a short period of time. The studies made by Gerstle and Kemnitz and
Darley, et al, indicate that the mean rate of NO production would
/\
yield approximately 1 Ib/ton of material initially present. Burkle,
et al, determined that 4 Ib of NO per ton of cord wood was produced
/^
when burned in a trench incinerator. This higher rate is due, no
doubt, to the extended residence time at the peak temperature achieved
in a trench type incinerator.
The data shown in Table 3.4-5 indicates that as the wood content
of the fuel increases, the emissions of hydrocarbon and carbon
monoxide decrease.
Note that the reported figures for particulate emissions are
essentially similar. What effect the wood content of the waste would
have on the particulate emission is not known. For the purposes of
this study, the figure found for landscape refuse will be used.
While moisture content will affect the emissions, no data has
been reported in this regard with the exception of two of the brush
P
and prunings tests. However, there is no agreement in those figures
that emissions increase as moisture content increases and, indeed,
the magnitudes of emission remain the same.
-------
3-37
Table 3.4-3. Emissions From Open Burning of Municipal Refuse
Emi
Parti cul ate
16 (14 to 18)
-
30
20-59
ssions,
CO
85 (80
40
0
«.
600
Ib/ton of waste
HCa
to 90) 30
8
80
115f
N0xb S02
4 to 9
4 3
0.6 0.3
» .
1 -
Reference
Number
2
3C
5e
4d
?9
a) HC expressed as methane.
b) NO expressed as NOp-
c) Whether figures are based on actual testing is not stated.
d) Measured emission from pilot-scale trench incinerator varied
directly in proportion to the amount of combustion air admitted.
e) Figures based on estimate only.
f) Reported values for saturated HC (30) and methane (85) were
assumed to be expressed as methane.
g) Figures are result of testing backyard incinerators.
Table 3.4-4. Emissions From Open Burning of Automobile Components
Emissions, Ib/ton of Waste Reference
Particulate . CO HCa NOYb S09 Number
J\ £
100 125 30 2 to 5 - 2C
a) HC expressed as methane.
b) NO expressed as NOp.
c) Figures based on tests of upholstery, belts, hoses, and
tires burned in-common.
-------
Table 3.4-5. Emissions From Open Burning of Horticultural Refuse
Type of Refuse Burned
Fruit Prunings
Landscape Refuse
Grass Stubble and Straw
R1ce Straw
Barley Straw
Native Brush
Redwood Chips
Fir Chips
Enri
Particulate
_
17 (12 to 23)
0
15.6 (9 to 26)
-
.
-
-
ssions, Ib/ton o
CO
45 to 87
65 (50 to 80)
0
101 (56 to 147)
56 to 90
60 to 106
36 to 175
70
35
f waste
HCa'b
3.9 to 18.5
30 (25 to 35)
415
16 (5 to 25)
11.5 to 15.4
14.5 to 24.3
2.9 to 48.2
2.9
3.7
| N°x
-
1 to 4
0.6
-
-
-
-
-
so2
_
-
-
-
-
-
-
-
Reference
Number
6
2
5
8
6
6
6
6
6
a) HC expressed as methane.
b) Where HC was reported as carbon, figures were converted to methane.
c) N0x expressed as N02-
co
i
Co
CO
-------
3-39
REFERENCES 3.4
1. Waste Problems of Agriculture and Forestry. Environmental Science
and Technology 2: 498, July 1968.
2. Gerstle, R.W., and D.A. Kemnitz, Atmospheric Emissions From Open
Burning. J. Air Pollution Control Association. V7_:324-327, May 1967.
3. Weisburd, M.I.., and S.S. Griswold (eds.). Air Pollution Control Field
Operations Manual, National Air Pollution Control Administration,
Raleigh, North Carolina, Public Health Service Publication 937.
p. 29. 1962.
4- Burkle, J.O., J.A. Dorsey, B.T. Riley. The Effects of the Operating
Variable and Refuse Types on the Emissions from a Pilot-Scale Trench
Incinerator. In: Proceedings of 1968 National Incinerator Conference,
ASME, New York, 1968. p. 34-41.
5. Estimated Major Air Contaminant Emissions, State of New York, Department
of Health, Albany, New York. Reviewed April 1, 1968. Table A-9 (unpublished)
6. Darley, E.F., et al. Contribution of Burning of Agricultural Wastes to
Photochemical Air Pollution. J. Air Pollution Control Association,
16:685-690, December 1966.
7. Feldstein, M., et al. The Contribution of the Open Burning of Land
Clearing Debris to Air Pollution, J. Air Pollution Control Association.
13j_542-545, November 1963.
8. Boubel, R.W., E.F. Darley, and E.A. Shuck. Emissions from Burning Grass
Stubble and Straw. J. Air Pollution Control Association. 1_9_:497-500,
July 1969.
-------
4.-- CHEMICAL MANUFACTURING INDUSTRIES
This section deals with the emissions from the manufacture
and/or use of chemicals or chemical products. Potential emissions
from many of these processes are high, but due to the nature of
these compounds, they are, in general, recovered as an economic
necessity to the profitable operation of the process. In still
other cases, the manufacturing operation is run as a closed
system allowing little or no escape to the atmosphere of any of
the reactants or by-products.
In general, the emission which can reach the atmosphere
from these processes is primarily gaseous and is controlled
by incineration, adsorption, or absorption. In some cases,
however, particulate emissions are also a problem from the
manufacturing processes. When these occur, they are generally
particles of extremely small size and require very efficient
treatment for removal.
In a few cases, such as carbon black, charcoal, and rayon
manufacture, emission of various noxious gases is a major problem
which could be controlled, but control is apparently not
economically attractive.
For many chemical processes emission data is extremely sparse,
or non existent. Emissions were therefore frequently estimated
based on material balances, yields, or similar processes. These
factors are,of course,not as reliable as measured emission data.
Since the major emissions from the processes presented in this
section are gases, no particle size summary is presented.
-------
4-2
4.1 AMMONIA
Process Description1'2*3
The manufacture of ammonia (NHg) is accomplished primarily by
the catalytic reaction of hydrogen and nitrogen at high temperatures and
pressures. In a typical modern plant as shown in Figure 4.1-1 a hydro-
carbon feed stream (usually natural gas) is desulfurized to less than 2 ppm
of sulfur, mixed with steam and catalytically reformed to carbon monoxide
and hydrogen. A nickel-base catalyst is used in this high temperature
(1400-1500°F) step. Air is introduced into the secondary reformer to
supply oxygen and provide a nitrogen to hydrogen ratio of 1:3. The
gases then enter a two-stage shift converter which reacts the carbon
monoxide with water vapor to form carbon dioxide and hydrogen. The gas
stream is then scrubbed with either monoethanolamine (MEA), hot potassium
carbonate or other ($2 absorbing solutions to yield a gas containing less
than 1% COp. A methanator may then be used to convert quantities of
unreacted CO to inert CH. before the gasess now largely nitrogen and hydrogen
in a ratio of 1:3, are compressed to 150 to 300 atmospheres and passed to the
converter. Alternatively, the gases leaving the COg scrubber may pass through
a CO scrubber where they are scrubbed with an ammoniacal solution of copper
formate and then passed to the converter.
Most converters in the United States operate at about 150 atmospheres
of pressure (2200 psi) and 1000°F with a once-through yield of 15%. The
synthesis gases react in the converter to form ammonia in the presence of an
iron oxide catalyst whose activity is increased by adding other trace metaV
oxides. Since CO greatly reduces the activity of the catalyst, its concentration
must be reduced to a level of 10 ppm or less.
-------
CH4 or
HC Feed
Steom ^
Fuel
Prim
Refoi
CH
CH<
Flue Gas
> I
T> Air - CO 1- 3H2 ^ N2 t 3H2-*-2NH3
^ + Air >-COt2H2-r-N2 C021-H2 CH4 + H20
oo
Figure 4.I-I Typical Ammonia Manufacturing Process
-------
4-4
The converted ammonia gases are partially recycled, and
the balance is cooled and compressed to liquefy the ammonia. The non-
condensable portion of the gas stream consisting of unreacted nitrogen,
hydrogen, and traces of inerts such as methane, carbon monoxide, and
argon, is largely recycled to the converter. However, to prevent
accumulation of the inerts, some of the non-condensable gases must be
purged from the system.
When a carbon monoxide scrubber is used 1n the synthesis gas
preparation system, the scrubber solution (copper formate) regenerator off-
gases contain significant amounts of carbon monoxide (73%) and ammonia (4%) in
addition to hydrogen, nitrogen, and carbon dioxide. This gas may be scrubbed
to recover ammonia and then burned to utilize the CO fuel value.
Emissions of ammonia also occur from the storage and loading area.
Factors Affecting Emissions
The major factor affecting emissions from the synthesis of ammonia
is the general operating condition of the plant such as the condition of
compressor and valve seals, relief valve settings, product loading operations,
etc. Plants equipped with a methanator will have much lower CO emissions as
compared to plants using a CO scrubbing system.
Emissions
Since a portion of the uncondensed exit gases are recycled, all
ammonia plants must bleed-off or purge some of these gases in order to prevent
the accumulation of inerts in the system. These gases contain about 15% ammonia.
Gases from the loading and storage operations contain 60-100% ammonia. These
gases may be scrubbed with water to reduce the atmospheric emissions. In addition,
emissions of'CO and ammonia can occur from those plants equipped with copper formate
CO scrubbing systems.
Emission factors based on data in the Appendix are presented in
Table 4.1-1.
-------
4-5
Table 4.1-1 Uncontrolled Emissions from Ammonia Manufacturing, Ibs/ton
NHs CO CH4
Plants with Methanator
Purge Gasa 3(2 to 4) Neg. 90(40 to 130)
Storage and Loading3 200(150 to 250) 0 0
Total 203(152 to 254) Neg. 90
Plants with CO Absorber and Regeneration System
Regenerator Exttb 7 200 0
Purge Gas* 3(2 to 4) Neg. 90(40 to 130)
Storage and Loadinga 200(150 to 250) 0 0
Total 210(152 to 254) 200 90(40 to 130)
a) NH3 emissions can be reduced by 99% by pass.ing through a 3 stage packed
tower water scrubber. CH4 is not reduced.
b) A two stage water scrubber and incineration system can reduce
these emissions to a negligible amount.
Note: Ranges in emissions are due to variations in gas flows and concentrations,
and not any specific factor.
Reliability of Emission Factors
Though based on limited emission data, the ammonia processes used
today are well defined, and data based on only one plant should represent
emissions from all plants of similar design. The emission factors
presented here are considered reliable, but would benefit from additional
emission data. Table 4.1-2 presents the factor ranking.
Table 4.1-2. Ammonia Emission Factor Ranking
Emission Data Process Data Engineering Analysis Total
0-20 0-10 0-10
58 8 21
No assumptions were made in determining these emission factors.
Additional detailed emission test data for ammonia manufacture appear
desirable.
-------
4-6
APPENDIX 4.1
Emission Calculations for a 450 ton per day Ammonia Plant. (Reference 4)
Purge Gas
100-200 cfm, 15% NH3
150 ft3 x .15 MM., x 1440 min x 17 Ib/lb mol = 1450 Ibs/day - 33%
j 3
min day 380 ft /lb mol
or 3.2-33% Ibs/ton product
CO at about 10 ppm in this gas stream would produce a negligible emission.
CH4 at 1% (± 50%) in this gas stream would produce an emission of 91 Ibs/ton.a
Loading and Storage
Approximately 1800 cfm @ 60-100% NH3
1800 ft^ x .80 NH3 x 1440 min. x 17. = 93,000 - 25% Ibs/day
min day 380 or 208 - 25% Ibs/ton product
Combined purge and storage emissions after water scrubber
600 cfm 0.2% NH3, CH4 is not changed.
600 ft3 x 0.0020 NH3 x 1440 min x J7 = 77.5 Ibs/day
min day 380 or 0.17 Ibs/ton product
Emissions from CO Scrubber when used in system;
1200 cfm, 73% CO, 4% NH3
1200 I*3, x .73 CO x 1440 min. x 28_ = 93,000 Ibs CO/day
min day 380 or 206 Ibs CO/ton product
1200 l*i x 0.04 NH3 x 1440 min. x 1_7_ = 3110 Ibs NH3/day
min day 380 or 6.9 Ibs NH3/ton product
These emissions can be virtually eliminated by a water scrubber
and final combustion of the gases in a boiler.
a) CH4 based on very limited gas concentration data in Reference 3, page 18.
-------
4-7
REFERENCES 4.1
1. Shreve, R.N. Chemical Process Industries, 3rd Edition. New York,
McGraw Hill Book Company. 1967. p. 105-106, 302-314.
2. Gucci one, E. The New Look in Ammonia Plants. Chem. Eng.
721:124-126, November 22, 1965.
3. Axel rod, L.C., and T.E. O'Hare. Production of Synthetic Ammonia.
New York* M.W. Kellogg Company, 1964.
4. Burns, W.E. and R.R. McMullan. No Noxious Ammonia Odors Here.
Oil and Gas Journal, p. 129-131, February 25, 1967.
GENERAL
Sittig, M. Inorganic Chemical and Metallurgical Process Encyclopedia
Park Ridge, New Jersey, Noyes Development Corporation. 1968. p. 56.
Caplow, S.D. and S.A. Bresler. Economics of Gas Turbine Drives.
Chem. Eng. 74:103, March 27, 1967.
Bresler, S.A. and G.R. James. Questions and Answers on Today's
Ammonia Plants. Chem. Eng. 72^:109, June 21, 1965.
Chopey, N.P. Methane Reforming: Pressure Goes Up. Chem. Eng.
68:158-161, April 17, 1961.
-------
4-8
4.2 ASPHALT ROOFING
ProcessJDescri pti on
The manufacture of asphalt roofing felts and shingles
involves saturating a fiber media with asphalt by means of
dipping and/or spraying.
While not always done at the same site, an integral
part of the operation is the preparation of the asphalt
saturant, This preparation consists of oxidizing the asphalt
and i§ accomplished by bubbling air through liquid (430-500°F)
asphalt for 8 to 16 hours. The industry refers to this operation
as "blowing". The time required for blowing depends on the
desired properties of the saturant. It had been the practice
to blqw the asphalt in horizontal stills where the material
loss ranges from 3 to 5%J Most of this material is recovered
by venting the exhaust gases through oil knock-out tanks
which are an integral part of the process. The recaptured
mist, is not reintroduced into the saturant but is used for
other products such as cut-back asphalt. Thus, in horizontal
stills, it requires approximately 1.05 tons of asphalt to produce
1.00. tojn.i of saturant. However, most roofing manufacturing firms
are eurrently using vertical stills from which the material loss
is 1. tO> 2% over a 1 1/2 to 5 hour cycle. The ameliorating effect
of these stills, regarding emissions, is significant.
After blowing, the saturant is transported to the saturation
tank or spray area. The saturation of the felts is accomplished
at temperatures of 400-500°F by dipping, by high pressure sprays.*
or be-th. Where both methods are useds the spray is preliminary
-------
4-9
to the dipping. This spray, applied to one side of the felt only,
drives the moisture out the other side. The felts must contain
less than 7% moisture to prevent subsequent blistering of the.
asphalt.
The entire saturation process is limited by the properties
of the felt and the speed at which the felt can be fed to the
saturator. Maximum speeds of 600 fpm are obtained for 15 to 30 Ib.
felt and 400-500 fpm for the heavier weights. However, the speed
on the average installation is more like 250-275 fpm. Normally,
felts are 3 or 4' ft. wide. On rare occasions however, 6 ft. wide
felts are run.
Felts are made in varying weights: . 15, 30, and 55 lb/100 sq.
ft. (1 square). Often granules of gravel or mica are applied
to the 55 Ib. felt making it suitable for use as shingles. Dust
generation may accompany this procedure. Regardless of the weight
of the final product, the makeup is approximately 40% dry felt
and 60% asphalt saturant.
Common methods of air pollution control at asphalt
saturating plants include complete enclosure of the spray area
and saturator followed by good ventilation through one or
more collection devices including combinations of wet scrubbers,
and two-stage low voltage electrical precipitators, or cyclones and
fabric filters. A low voltage electrical precipitator preceded
by a wet scrubber has been reported to provide a collection
efficiency of about 85%.
Factors Affecting Emissions
Factors affecting emissions include the temperature of the
asphalts, the amount of volatiles in the asphalt, the amount of
spray air used initially, the feed rate, width, and weight of the
-------
4-10
felt, the moisture content of the felt, the amount of asphalt
applied to felts by spraying, the rate of ventilation of the
system, and the efficiency and degree of maintenance of control
equipment used.
Emissions
Table 4.2-1 lists the emission factors derived for the
asphalt blowing and felt saturation processes. Limited test
data is available and the factors are based on the information
obtained from industry as well as published works. Appendix 4.2
contains a compilation of available data. Gaseous emissions
from the saturation process are unknown. It is likely that such
emissions are slight due to the initial driving off of these
contaminants during the blowing process. Likewise, no data has
been found for emissions from saturation processes which employ
the use of sprays. The spray will increase emissions due to
the entrainment of asphalt in the water particles which are
driven through and out the lee side of the felt. Factors given
for such operation in Table 4.2-1 are engineering estimates which
comport with previously used hourly emission rates. (See
Appendix 4.2 for this correlation.) Ranges in emissions were not given
since the reported information did not provide a basis for estimation.
Table 4.2-1. Emission Factors for Asphalt Roofing
Uncontrolled Emissions. Ib/ton of saturated felt
Operation Particulateb HCa CO
Asphalt Blowing 2.5 1.5 0.9
Felt Saturation
a) Dipping only 1
b) Dipping and spraying 2
c) Spraying only 3
" ' ' '" " ' " i I !- 11.1 II I "i Mil. I i - ""' - -i-r-W-.--.-i . , , _JWJ
a) HC expressed as methane.
b) Low voltage precipitator can reduce emissions by about 60%;
when used in combination with a scrubber, overan efficiency
is about 85%.
-------
4-11
Reliability of Emission Factors
The factors listed in Table 4.2-1 are based on limited data,
and gaseo'us data were not available for the saturation process.
The factors for asphalt blowing and the dipping-only saturation
.process are based on test data and are felt to be representative.
The factors developed for the dipping-and-spraying and the
spraying-only saturation processes are based on engineering
judgment arid are therefore to be considered questionable. Further
work in this area is justified, especially regarding the gaseous
emissions from,the various saturation processes. Emission factor
rankings are presented in Table 4.2-2.
Table 4.2-2. Emission Factor Ranking for Asphalt Roofing
Process
Asphalt Blowing
Saturation
a) Dipping only
b) Spraying and dipping
c) Spraying only
Emission
Data
0-20
10
10
0
0
Process
Data
0-10
8
8
8
8
Engineering
Analysis
0-10
3
3
3
3
Total
21
21
11
11
No major assumptions were made except that the factors for
the spraying-and-dipping and the spraying-only saturation processes
were assumed to be 200% and 300%,respectively»of that found for
the dipping-only process.
-------
4-12
APPENDIX 4.2
A. Reported Emissions from Asphalt Blowing
The test reported in Reference 2 provides emission
information for a 24 tons per hour asphalt blowing operation.
This information is compiled in Table 4.2-3.
2
Table 4.2-3. Test Data from Asphalt Blowing Operation
Exhaust gas, Temp. Particulate HCa, CO, Input
scfm °F grains/scf ppm ppm tons/hr
8400 210 1.30b 2500 900 24
a) HC expressed as methane [Note: original text is in conflict
whether HC is expressed as carbon or methane.]
b) Reading taken in exhaust stack after steam spray-baffle
arrangement was higher (1.45). However, since the baffles
are not an integral part of the process, the reading taken
ahead of the baffles is used.
The emissions given in Table 4.2-3 are converted to Ib/ton and
reported in Table 4.2-4.
Table 4.2-4. Emissions from Asphalt Blowing Operation,
Ib/ton of input5
f articulate HC.b CO
3,.9 2.25 1.38
a) Conversion of data given in Table 4.2-3.
b). HC expressed as methane.
-------
4-13
However, the figures in Table 4.2-4 are based on Ib/ton of asphalt
input. It should be noted that approximately 5%. of the initial
material is lost in the blowing-process (See main text. Process
Description). Further, only 61.5% of the final product (asphalt
saturated felts) is asphalt. All emissions for this section will
be based on the final product,viz. , Ib/ton of asphalt saturated
felts. Thus it requires 0.65 tons (105% x 61.5% x 1 ton) of
unoxidized asphalt to produce 1 ton of saturated felts. The
factors reported in Table 4.2-1 are 65% of those reported in
Table 4.2-4 and are rounded off for ease of use.
B. Emissions from Felt Saturation
No gaseous emissions have been reported from this process
and very little information is available regarding particulate
emissions^ The published emissions are based on a Ib/hr basis
and are shown in Table 4.2-5. :
Table 4.2-5. Reported Uncontrolled Particulate Emissions
from Felt Saturation
Emissions, Ib/hr Reference Number
67.7 3
55.0 3
71.4 3
20a 4
a) Emission after control device.
An unpublished test reported 24 Ib/hr uncontrolled particulate
emissions from a process operating at the rate of 22.5 tons
-------
4-14
finished product/hr.1 (Approximately 1.0 Ib/ton of saturated felt).
This process did not utilize sprays. This fact seems to account
for the relatively low emission rate. The highest reported rate
shown in Table 4.2-5 is approximately three time the above figure.
Since spraying increases the potential particulate emissions, the
factors are arbitrarily weighted as follows:
a) Dipping only 100%
b) Dipping and Spraying 200%
c) Spraying only 300%
That, is to say, the factor for Spraying-Only is 300% greater than
for Dipping-Only.
-------
4-15
REFERENCES 4.2
1. Private Communication with the Philip Carey Corp., Cincinnati,
Ohio, January 8, 1970.
2. Von Lehmden, D.J., R.P. Hangebrauck, and J.E. Meeker. Poly-
nuclear Hydrocarbon Emissions from Selected industrial Processes.
J. Air Pollution Control Association. ljj_:306-312, July 1965.
3. Weiss, S.M. In: Air Pollution Engineering Manual. Danielson,
JiA. (:e'd.-). National Air Pollution Control Administration.
Raleigh, N.-C. Public Health Service Publication 999-AP-40. 1967,
p. 378-383.
4. Goldfield, J., and R.G. McAnlis. Low Voltage Electrostatic
Precipitators to Collect Oil Mists from Roofing Felt Asphalt
. Saturators. and Stills. Industrial Hygiene Association Journal.
July-August 1963.
-------
4-16
4.3 CARBON BLACK
PrSce'ss Description
Carbon black is produced by reacting a hydrocarbon fuel
such as oil and/or gas with a limited supply of air at temperatures
of 2500°F - 3000°F. Part of the fuel is burned to C02, CO, and
water thus generating heat for the combustion of fresh feed. The
un&ufnt carbon is collected as a black fluffy particle. Three
basic processes currently exist in the United States for producing
this compound. They are: The furnace process accounting for
ab<3u£ 83% of production; the older channel process which accounts
for' about 6% of production; and the thermal process. Atmospheric
pollutants from the thermal process are negligible since the exit
gases Which are rich in hydrogen are used as fuel in the process.
In contrast, the pollutants emitted from the channel process are
excessive and characterized by copious amounts of highly visible
black smoke. Emissions from the furnace process consist of carbon
dioxide, nitrogen, carbon monoxide, hydrogen, hydrocarbons, some
particulate matter, and some sulfur compounds.
In the channel black process, natural gas is burned with a
limited air supply in long low buildings containing 3000 to 4000
small burners. The flame impinges on long steel channel sections
that swing continuously over the flame. Carbon black, deposited
on the channelsf is scraped off and falls into collecting hoppers.
The combustion gases containing solid carbon not collected
on the channels, in addition to carbon monoxide and other comb.us.tipn
products, are then vented directly from the building. Approximately
1 to 1.5 pounds of carbon black are produced from the 32 pounds
3 123
of carbon available in 1000 ft of natural gas. ' ' The balance
of the carbon is lost as COS C02s hydrocarbons, and particulate.
-------
4-17
The furnace process is sub-divided into either the gas or oil
process depending on the primary fuel used to produce the carbon
black. In either case, gas (gas process) or gas and oil (oil
process) are injected into a reactor with a limited supply of
combustion air. Common practice currently consists of also
feeding some oil to the reactor in the gas process. This enrichment
is on the order of 5.65 gallons of oil per 1000 ft gas. Part
of the feed is burned with the combustion air to provide heat
for decomposing the balance of the feed at a temperature of
about 2600 - 2900°F. The combustion gases containing the hot
carbon are then rapidly cooled to a temperature of about 500°F by
water sprays and by radiant cooling. Yields of 10 to 30% are
obtained in the gas process (i.e., 10 to 30% of the carbon in
the feed is recovered as carbon black). Approximately 55% of the
oil feed is recovered as carbon in the oil process.
The largest and most important portion of the furnace process
\
consists of the particulate or carbon black removal equipment.
While many combinations of control equipment exist, common practice
as shown in Figure 4.3-1 is to provide an electrostatic precipitator,
a cyclone, and a fabric filter system in series to collect the
carbon black. In newer plants, the electrostatic precipitator may
be omitted. In some older plants the final fabric filter system
is not used, or a scrubber may be used in its place. Control of
gaseous emissions of carbon monoxide and hydrocarbons is not
practiced in the United States. Incineration of these gases is
feasible, however, and is practiced in Great Britain.
In thermal black plants, natural gas is decomposed by heat
in the absence of air or flame. In this cyclic operation,
methane is pyrolyzed or decomposed by passing it over a heated
brick checkerwork at a temperature of about 3000°F. (CH^ C + 2H2).
-------
= PARTICULATE EMISSION LBS. PER TON
FABRIC FILTER SYSTEM
£=10,OR FINAL
SCRUBBER E=60
E=220
I
00
PRODUCT TO SCREENING,DRYING OPERATIONS
Figure 4.3-1. General process flow of furnace process carbon black
manufacturing I, 3.
-------
4-19
This checker-work is first heated by burning hydrogen generated in
the decomposition reaction and/or by additional gas fuel. While
one set of checkerwork is decomposing gas to produce carbon black,
the other set is being heated. The gas flows are then switched
and the heating/decomposition cycle is repeated. The decomposed
gas is then cooled and the carbon black removed by a series of
cyclones and fabric filters. The exit gas consisting largely
of hydrogen (85%), methane (5%), and nitrogen is then recycled
to the process burners or used to generate steam in a boiler.
Due to the recycling of the effluent gases, there are essentially
no atmospheric emissions from this process. Particulate emissions
can, of course,occur from product handling.
Factors Affecti ng Emi ssions
The most important factor affecting emissions is the basic
manufacturing process and its inherent efficiency. Thus, emissions
from the channel black process are excessive, while those from
the thermal process are negligible. Particulate emissions
from the furnace process are affected by the type of control
equipment used. Gaseous emissions, .are largely determined by
the overall yield, type of fuel (that is, liquid or gas), the
reaction time and temperature, the ratio of gas to oil in the
feed, and the amount of combustion air.
Emissions
Table 4.3-1 presents the calculated emissions from the
various carbon black processes. Nitrogen oxide emissions are
not included since data are not available and they are believed
to be low due to the lack of available oxygen in the reaction.
-------
4-20
Table 4.3-1. Emissions From Carbon Black Manufacturing Processes,
Process
Channel f
Thermal
Furnace
Gas
Ibs/ton of product
Particulate CO H0S \
(26,000 to <-
2300(2000 to 5000) 33,50044,000) - 11 ,500(
neg. neg. neg. n<
/220b\ 5,300(4200 to neg. 1,81
HC
Gas
Oil
/220U \ 5,300(4200 to
f 60C 1 640°)
V 10d/ 4,500(3600 to
V / 5400)
neg.
38Se
1,800
400 -
a) As methane.
b) 90% overall collection efficiency, that is, no collection after
cyclone^
c) 97% overall collection efficiency, that is, cyclones followed
by s cvMjb.be r.
d) 99.5% overall collection efficiency, that is, fabric filter
system:.
e) S = Height % sulfur in feed.
f) Based oa yield of 1.5 pounds of carbon black per 1000 ft. 3
of gas-. feed.
Note: Emi%s,ion ranges are due to variations in operating conditions
and- not any specific factors.
quantities of carbonyl sulfide, thiophene and carbon
disulfid^ have also been reported when oil is used in the feed.
Most of the gas used in the carbon black industry is scrubbed to
remove. sulifur compounds. Oil feeds may, however, contain more than
1% of sujlf.uj-. When sulfur contents increase beyond about 1.2%
by weighjt,,, Additional H2S is not produced and free sulfur is formed.
Addi-tional emissions may occur from the grinding, screening,
and dry ifigr operations at a carbon black plant. These emissions
are usually controlled by a pneumatic system which exhausts into
a bag filter system. However, poorly designed or maintained
equipment can result in spills and leaks. Due to the variability
of these emissions, no emission estimate is possible.
-------
4-21
Reliability of Emission Factors
Factors for the channel black process are questionable
due to.a complete absence of emission data. Factors for
furnace black plants are considered good since exit gas concentrations
and considerable process throughput data were available.
Table 4.3-2 presents the factor ranking.
Table 4.3-2. Carbon Black Emission Factor Ranking
Channel Process
Furnace Process
Emission
Data
0-20
0
7
Process
Data
0-10
5
8
Engineering
Analysis
0-10
5
8
Total
10
23
No major assumptions were made in determining the emissions
from the furnace process. For the channel black process, gaseous
emissions were assumed to be similar in composition to those
from the gas furnace process. Product yield was based on reported
data, and the balance of the feed was lost to the atmosphere.
Variations in emissions due to these assumptions are shown in
Table 4.3-1.
-------
4-22
APPENDIX 4.3
A. CARBON BALANCE TO ESTIMATE EXIT GAS VOLUMES - FURNACE PROCESS
1. Oil Furnace Process Input (Intermediate super abrasion grade)
220 gal oil/hr
12,200 ft3 gas/hr
190,000 ft3 air/hr
220 gal oil/hr x 7.1 Ib/gal x .90 C = 1408 IbC/hr entering
reactor in oil
12,200 ft3 gas/hr x 12 x .97 C = 374 IbC/hr entering
380
reactor in gas
55% of oil feed is converted to carbon black.
0.55 x 1408 = 774 Ib carbon black produced
0.45 x 1408 = 634 Ib carbon not converted to carbon black
634 Ibs C from oil + 374 Ibs C from gas = 1008 Ibs C in exit gas
145
Exit gas carbon composition is: ' '
4.9% C02
11.4% CO
0.8% CH4
0.5% C2H2
Exit gas rate may be calculated from carbon mass balance,
namely:
(% Carbon)(exit gas rate) x 12 Ibs/lb mol = Ibs carbon
380 ft-Vlb mol in exit gas
-------
4-23
Let Q = exit gas rate
[(0.049 Q + 0.114 Q + 0.008 Q) 12l +
U CO, CO CH. 380J
!0.005 Q(24 Ibs C/lb mol CpHp
380 ft3/lb mol
= 1008 Ibs carbon/hr
0.00534 Q + 0.00032 Q =1008
Q = 180,000 ft3/hr (dry basis rounded off)
= 3000 SCFM @ 60°F, dry basis
or.^3000 SCFM per 774 Ibs carbon black produced/hr
= 3900 SCFM per 1000 Ibs carbon black/hr
dry basis (calculated).
4
Calculations based on data in article by Reinke and Ruble
gives 25,700 SCFM (wet) per 3000 Ibs of product/hr, or
25.700 x .60 H20 x 1Q"3 = 5140 SCFM/1000 Ib C/hr (dry),
3000
Therefore use an average value of 4500 SCFM (dry basis)
per 1000 Ibs of carbon black produced or 9000 SCFM per ton of
carbon black.
2. Gas Furnace Process
560 ft3/min of gasa
2520 ft3/min of air
560 ft3/min x 12 x .97 x 60 min/hr = 1030 Ib C/hr entering
380
a) Oil is sometimes added at the rate of 5.5 gallons per 1000 ftv
of gas. This has very little effect on the overall emission
rate per ton of product.
-------
4-24
25% conversion to carbon black = 258 Ib carbon black/hr product,
Lbs gaseous carbon in exit gas = (1030 - 258) = 772 Ib/hr.
Exit gas carbon composition is (dry basis):
C02 5%
CO 5%
CH,
4
3
Let Q = ft /hr of exit gas flow
[(.05 + .05 + .01) x 12-, Q + [>01 x 24J Q = 772 lbs carbon
* 380 in exit gas
.00348 Q + .00063 Q = 772
.00411 Q = 772
Q = 187,000 ft3/hr (dry basis)
= 3130 SCFM dry basis for 258 Ib/hr of
product
For 1000 lbs of product, 3130 = 12,100 SCFM dry basis at 60°F.
7158
Use 24,000 SCFM/ton of carbon black.
B. GASEOUS EMISSIONS - FURNACE PROCESSES
Average Exit Gas Composition, percent by volume, dry basis.
145 1
Oil Process '* Gas Process
C02 4.9 5 ± 20%
CO 11.4 5 ± 20% (The range was
CH4 0.8 1 estimated.)
C2H2 0.5 1
H2 13.5 17 - 18
H2S 0.035
N0 Balance Balance
-------
4-25
1. Oil Process - per ton of product
CO: 9000 ft3 (dry basis) x 60 min/hr x .114 x 28 Ib/mol
mTn 380 ftVmoi
^..
= 4550 Ibs/ton
CH.: 540,000 ft3/hr x .008 x 16 = 181 Ibs/ton
q 380
C9H9: (expressed as CH.): 540,000 ft3/hr x .005 x 32
c *- ' 4 380
=228 Ibs/ton
H9S: 540,000 ft3/hr x 0.00035 x 34 = 16.9 Ibs/ton
* 380
(See later calculation for HLS emissions).
2. Gas Process - per ton of product
CO: 24,000 ft3/nrm x 60 min/hr x .05 x 28 = 5300 lbs/tona± 20%
380
CH.: 1,440,000 ft3/hr x .01 x 16 = 606 lbs/tonb
4 380
C0H0: (as CH.): 1,440,000 ft3/hr x .01 x 32 = 1212 lbs/tonc
i d 4 380
a) Represents 2280 Ibs of carbon (5300 x 12/28), C0? also represents
2280 Ibs of carbon
b) Represents 460 Ibs of carbon
c) Represents 910 Ibs of carbon
-------
4-26
Nitrogen Oxide Emissions
Due to lack of oxygen in the high temperature zones, very
little nitric oxide will form. No emission data are available.
Sulfur Emissions
Drogin reports 90% of S goes to effluent gas. For low
sulfur feeds this sulfur appears largely as hLS, not SOp. Free
sulfur could also be formed but this would be collected as a
particulate.
Based on 90% S emitted as HLS, emission factor for oil
process is:
34 H2S x .90 x S x 570 gal oil x 7.1 Ib = 38.6S
Where S
in feed
32 s 10° ton Prod 9al Where S is weight
570 gal of oil = 220 x 2000 Ibs/ton
ton 774 lbs/220 gal
C. PARTICIPATE EMISSIONS - FURNACE PROCESS - (either gas or oil)
Since production is the amount collected in the particulate
control system, the efficiency of the control system can be
mathematically related to the production:
Emission, e
Inlet from reactor, i
Production, p
-------
4-27
i = e + p
E = Collector Efficiency = i - e = £
i i
iE = i-e
i (1-E) = e
and i = £
E
Therefore e = £ M_E)
Particulate Emissions per ton of product!on.are therefore:
145
@.90% collection efficiency, that is, no collection after cyclone ' '
e = 2000 (1 - .90) = 220 Ibs/ton
.90
@ 97% collection efficiency, that is, with a scrubber following
. cyclone
e = 2000 (1- .97) = 61.9 Ibs/ton
.97
@ 99.5% (good fabric filter system)
e = 2000 (1- .995) = 10.05 Ibs/ton
005 , -
''J ' '. ." ic. . -'
D. CHANNEL PROCESS
Yield is 1 to 1.5 Ib per 1000 ft3 of gas.1'2
1000 ft3 gas contains about 32 Ib of available carbon (1000 x 12
380
= 32 Ib)
Therefore 30.5 Ibs of carbon are lost as particulate, COp,
CO and hydrocarbons for each 1.5 Ib of product (32-1.5 = 30.5).
Due to the higher excess air (open flame) less particulate
is initially formed as compared to the furnace process, and more
CO and C02 are formed.
In the gas furnace process about 25% of the feed (by weight)
is converted to solid carbon. Assume in channel black process that
-------
4-28
about 10% of feed is converted to solid carbon and balance is
split between CO, C02, and HC. For 1000 ft3 of gas entering
(32 Ib carbon), 1.5 Ib is product, and 1.7 Ib is lost in smoke
(3.2-1.5). This could vary up to 3-4 Ibs, depending on amount
of feed converted to solid carbon. Remaining 28.2 Ib carbon
(32-3.2) appears as a gas with the following assumed composition,
based on gas furnace process:
38.4% of carbon appeared as C0? in the exit gas (probably varies
from 30 to 50%)
38.4% of carbon appeared as CO in the exit gas (probably varies
from 30 to 50%)
23,2% of carbon appeared as HC in the exit gas (probably varies
from 10 to 30%)
on a Ibs per ton basis:
1.7 Ib part x 2000 Ib/ton = 2,260 Ib part/ton of product (2000
1.5 Ib/product to 5000)
28.2 x 2000 x 0.384 x 28 = 33,600 Ib CO/ton (Varies from 26,000
1.5 12 to 44,000)
28.2 x 2000 x 0.232 x J6. = 11,500 Ib CH./ton (Varies from 5,000
1.5 12 ^ to 15,000)
-------
4-29
REFERENCES 4.3
1. Drogin, I. Carbon Black. J. Air Pollution Control Association.
^"1^:216-228, April 1968.
2. Cox, J.T. High Quality - High Yield Carbon Black. Chem.
Eng. 57.:116-117, June 1950.
3. Shreve, R.N. Chemical Process Industries, 3rd Edition. New
York, McGraw-Hill Book Co. 1967, p. 124-130.
4. Reinke, R.A. and T.A. Ruble. Oil Black. Industrial and
Engineering Chemistry. 44_:685-694, April 1952.
5. Allan, D.L. The Prevention of Atmospheric Pollution in the
Carbon Black Industry. Chemistry and Industry, p. 1320-1324,
October 15, 1955.
GENERAL REFERENCES
«*« ' "
Powell, R. Carbon Black Technology. Noyes Development Company,
Park Ridge, New Jersey, 1968.
Chopey, N.P. New Entry Spurs Carbon Black Boom. Chem. Eng.
68(24):88-90, November 27, 1961.
Chemical Week, p. 79, June 16, 1962.
Shearon, et al. Industrial and Engineering Chemistry. 44:685,
1952.
-------
4-30
4.4 CHARCOAL
General Information
Charcoal is generally manufactured by means of pyrolysis, or
destructive distillation of wood waste from members of the deciduous
hardwood species. In 1958, approximately 214,000 tons of charcoal
were manufactured and shipments of that product totaled $14.7 million.
The production figures for 1963 had nearly doubled to 379,000 tons
2
and $28.4 million. This increase was registered in spite of the
decrease in profits due to the more economical production of
synthetic methanol, acetic acid, and acetone by methods other than
wood distillation.
Using maple as a typical hardwood, the composition is found to
be 50.64% carbon, 6.02% hydrogen, 41.74% oxygen, 0.25% nitrogen,
3
and 1.35% ash. All percentages are based on dry weight. In the
pyrolysis of wood, all the gases, tars, oils, acids, and water are
driven off leaving virtually pure carbon. All but the gas is a
useful by-product if recovered. The gas itself contains methane,
carbon monoxide, carbon dioxide, nitrogen oxides, and aldehydes.
By weight, two-thirds of the gas is carbon dioxide and therefore
the thermal value of the gaseous effluent is low. Table 4.4-1 lists
the products of wood distillation.
Other by-products of the pyrolysis may be refined to produce
methanol acetic acid, methyl acetone, tar and oil. All of these can,
however be manufactured more economically by other means; and wood
is distilled only for charcoal manufacture; there being no synthetic
counterpart for that product. Unfortunately,economics has rendered
the recovery of the distillate by-products unprofitable and they are.
generally permitted to be discharged to the atmosphere. This is
evidenced by a bluish plume similar to that resulting from open
burning of wood. The plume is very irritating to the eyes and throat.
-------
4-31
4
Table 4.4.1. Products From Hardwood Distillation, percent by weight
Charcoal 25.2
Water 46.7
tar, Oil 5.0
Acetic Acid 2.9
Crude Methanol 1.9
Carbon Monoxide 4.0a
Carbon Dioxide 12.3a
Methane 1.3a
Other Gases 0.7a
a) See Appendix 4.4 for calculations
Process Description
In manufacturing charcoal by destructive distillation or pyrolysis,
the wood is placed in a retort where it is externally heated for about
20 hours at 500 - 700°F. While the retort has air intakes at the bottom,
these are only used during startup and thereafter are closed. The
entire distillation cycle takes approximately 24 hours, the last 4 hours
being an exothermic reaction with no external heat being applied. A
white plume is observed during the early stages of the process, due
to the water being boiled off. Thereafter the plume, if recovery
of the by-products is not employed, is irritating and bluish in color.
If a recovery plant is utilized, the vapors formed by the heat-
treatment are passed through water-cooled condensers. The condensate
then refined while the remaining cool non-condensable gas is discharged
to the atmosphere as shown in Figure 4.4-1. Four tons of hardwood
are required to produce one ton of charcoal.
-------
4-32
A 1460 Ib. Gas
CONDENSER
COOLING WATER IN
VAPOR
I TON CHARCOAL
PRODUCT *-
R ETORT
T
f 320 Ib. CO
I IOOIb.CH4
S 980lb.C02
I 60 Ib. Other
^ 4540 CONDENSATE
2 CORDS OF WOOD
8000 Ibs. (As received )
HEAT INPUT, 28 x!06BTU/TON PRODUCT
Figure 4.4-1. Charcoal manufacturing processes with condenser.
-------
4-33
-,,. r-fx**^
Factors. Affecting Ennssi ons
The nature of pyrolysis is to produce copious quantities of
potential pollutants, a full three-fourths of the charged material
being driven off.
The most obvious factor affecting the composition and quantity
of the emissions is the recovery plant condenser. If the cooling
medium (chilled water, etc.) temperature is too high or the heat
transfer area is inadequate, complete condensation will not occur.
The most common situation, however, is the complete absence of a
condenser, the recovery of the condensable by-product being
unprofitable.
The emission is also increased by the introduction of outside air.
However*, the intakes are normally closed as soon as possible since
further injections of outside air, above that needed for start-up,
diminish the finished product.
. , ... Notwithstanding the absence of a recovery plant, the emission
can be controlled by means of an afterburner, since the unrecovered
by-products are combustible. Some charcoal plants presently control
emissions with this device. If the afterburner operates efficiently
no organic pollutants should escape into the atmosphere.
Emissions
Results of source testing of charcoal plants have not been
published nor have any unpublished results been found. However, an
engineering analysis of the by-products of the pyrolysis of hardwood
provides a reasonably accurate estimate of the kinds and quantities
of emission. The quantity of pollutants resulting from the manu-
facture of one ton of charcoal (distillation of 4 tons of hardwood)
is shown in Table 4.4-2.
-------
4-34
Table 4.4-2. Emission Factors for the Manufacture of Charcoal,
Ib/ton of product
Pollutant Type of Manufacturing Operation
With Chemical Recovery Without Chemical
Plant Recovery Plant
CO 320a 320a
HCb 100a TOO*
Other Gases (HCHO, N2, NO) 60
Crude Methanol - 152
Acetic Acid - 232
Particulate (Tar, Oil) - 400
a) Emissions are negligible if afterburner is used.
b) HC expressed as methane.
Reliability of Emission Factors
The factors presented in Table 4.4-2 were based on limited data
and were arrived at by material balance calculations. As shown in
Table 4.4-3 these factors are all ranked as questionable due.to the
lack of emission data.
Table 4.4-3. Emission Factor Ranking for Charcoal Manufacturing
Emission Data Process Data Engineering Analysis Total
0-20 0-10 0-10
0 6 8 14
-------
4-35
Further work in this area appears to be justified due to the
potential health hazards from these fumes and the growth rate of
this industry. To date, charcoal operations have been located in
rural areas and have not received much attention from an air
pollution standpoint.
The lack of emission data and the variance in the composition
of the raw product required the assumption that the reported products
of distillation are correct and relatively constant between the
various species of wood. Only a slight variance in the figures
reported in. Table 4.4-1 will greatly vary the emission factor.
-------
4-36
APPENDIX 4.4
It has been reported that the weight of gas driven off in the
pyrolysis of hardwood is 18.3% of the weight of the wood and the
weight of the resulting charcoal is 25.2% of the raw product. Thus
approximately 8000 Ib wood is required for the production of one
ton of charcoal and the gas thereby liberated weighs approximately
1460 Ib. The volumetric make up of this gas is 53% carbon dioxide,
27% carbon monoxide, and 15% methane. The remaining 5% shall be
designated "other"herein. To determine the weight of these
constituents (P ), find the weight a pound mole of the constituent
J\
gas (W ), multiply that by the total weight of flue gas (1460 Ib),
A
multiply by the volumetric percentage of the constituent (R ) and
/(
divide by the weight of a pound mole of the flue gas (W^).
Expressed in equation form
P . U x 1460 x R
Wt
for values Of W see Table 4.4-4
/\
for values of R see Table 4.4-4
y\
for values of W. see Table 4.4-5
Table 4.4-4 Gaseous Constituents of Wood. Percent by Volume
CO C02 CH4 Other
Mole Wt., Wx 28 44 16 28
Percent; by 27 53 15
Volume R
/\
a) Estimated average based on HCHO being 30, N? being 28, and
NO being 30.
a
-------
4-37
Table 4.4-5 Gaseous Constituents of Hood, Percent by Weight
Constituent Gas
CO
co2
CH4
Others
Wt» Total
Applying eq (2)
CO
co2
CH4
Other
% By Volume x Mole Wt. = Partial Mole Wt. of
Flue Gas
27 28 7.6
53 44 23.3
TE 16 2.4
5 28 1.4.
Weight of 1 mole of flue gas 34.7 Ib.
to each constituent gas:
P = 28 x 1460 x .27 _ 30Q lb
X O£U ID.
34.7
P = 44 x 1460 x .53 _ QOQ ,.
34.7
P - 16 x 1460 x .15 _ ,OQ ,b
A ...... | (JU 1 U .
34.7
P = 28 x 1460 x .05 s ,n ,.
34.7
1460 Ib.
Dividing the weights found above by the total weight of the 8000 Ib.
charge in the retort, we find that the percentages are as shown in Table 4.4-1
-------
4-38
REFERENCES 4.4
1. Census of Manufacturers 1958: V2, Part 2. U.S. Bureau of Census.
Washington, D.C. 1961.
2. Census of Manufacturers 1963: V2, Part 2. U.S. Bureau of Census.
Washington, D.C. 1966.
3. Zerban, A.H. and E.P. Nye. Power Plants. Scranton, International
Textbook Company, 1957. p. 56.
4. Shreve, R.N. Chemical Process Industries, 3rd Edition. New York,
McGraw-Hill, 1967. p. 619.
5. Private Communication with Kentucky Air Pollution Control
Commission, Frankfort, Kentucky August 29, 1969.
-------
4-39
4.5 HYDROFLUORIC ACID
Process Description
All hydrofluoric acid in the United States is currently produced by
reacting acid-grade fluorspar with sulfuric acid for 30-60 minutes in externally
fired rotary kilns at a temperature of 400-500°F according to the following
121
reaction: *"3
Ca F2 + H2S04 -> CaS04 + 2HF
The resulting gas is then cleaned, cooled, and absorbed in water and
weak hydrofluoric acid to form a strong acid solution. Anhydrous hydrofluoric
acid is formed by distilling 80% hydrofluoric acid and condensing the gaseous
HF which is driven off. The by-product, calcium sulfate or anhydrite is
recoverable. Figure 4.5-1 illustrates a typical process for producing 80% acid
and anhydrous acid; however, many variations in scrubber and absorber
arrangements may be used.
The fluorspar used to prepare hydrofluoric acid is a specially prepared
finely ground (approximately 95% through a 170 mesh screen) acid grade material
with a minimum purity of about 97-98% calcium fluoride as marketed. It also
contains some silicon dioxide and calcium carbonate in addition to trace amounts
of sulfur (less than 0.05%) and water. Process yields vary from 85 to 92%
depending on the purity of the reactants.
Air pollutant emissions are minimized by the scrubbing and absorption
systems used to purify and recover the HF. The initial scrubber utilizes
concentrated sulfuric acid as a scrubbing medium and is designed to remove dust,
SOp, and SO.,, sulfuric acid mist, and water vapor present in the gas stream
leaving the primary dust collector. The HF recovery system utilizes water and
hydrofluoric acid of increasing strengths to countercurrently cool and absorb
the HF. Anhydrous hydrofluoric acid 99.9% HF is produced by distilling the
80% acid. Uncondensed gases from the distillation process may be scrubbed
by sulfuric acid to recover additional HF and followed by a water scrubber
to remove any silicon tetrafluoride in the exit gases.
-------
H2S04
Cooler
V
u
>
u
<£
o
X
Oust
Seporotor
Pre mixer
CJ
CoF2
CaS04
Figure 4.5-1 Example Hydrofluoric Acid Manufacturing Process2
-------
4-41
Factors Affecting Emissions
The main factor affecting emissions is the general operating
condition of the plant and the equipment maintenance. Plants operating
in excess of rated capacity will have emissions many times those of a
plant operated within limits. Maintenance problems exist due to the
corrosive nature of hydrofluoric acid. Badly corroded scrubbers and/or
dust collectors will not operate at optimum efficiency.
Emissions
The exit gases from the final absorber contain small amounts
of HF, silicon tetrafluoride (SiF4), C02» and S02 and may be scrubbed
with a caustic solution to further reduce emissions. A final water
ejector, sometimes used to draw the gases through the absorption system,
will also reduce fluoride emissions. Emissions of non-condensable gases
from the anhydrous acid condenser consisting mainly of C02» SiF4, and
HF may also occur.
Table 4.5.1 Emissions from Hydrofluoric Acid Manufacturing Ibs/ton
Particulate 20a From raw material processing.
HF 50b From manufacturing process.
a) Based on Reference 1. Reported value is a maximum with dust control
system installed (Probably fabric filter, but reference was not specific).
b) ;A high efficiency water scrubber will reduce these emissions by 99.6%,
or down to 0.2 Ibs/ton. Based on Reference 4.
a,
Reliability of Emission Factor
Due to the very limited emission data available for this process,
and the variability in emissions caused by only small changes in scrubber
efficiency, these emission factors must be considered questionable. Additional
emission measurements for this process are warranted. Table 4.5.2 presents
the factor ranking.
Table 4.5.2 Emission Factor Ranking for Hydrofluoric Acid
Emission Data Process Data Engineering Analysis Total
0-20 0-10 0-10
35 3 11
-------
4-42
REFERENCES 4.5
Rogers, W.R. and K. Muller. Hydrofluoric Acid Manufacture.
Chemical Engineering Progress. 59_:85-88, May 1963.
Heller, A.N., S.T. Cuffe, and D.R. Goodwin. Inorganic
Chemical Industry, In: Air Pollution Volume III, 2nd Edition,
Stern, A.C. (ed.). New York, Academic Press Inc. 1968. p. 197-198.
Hydrofluoric Acid.Kirk-Othmer Encyclopedia of Chemical Technology
2nd Ed. 9:618-624. 1964.
Communication with Du Pont Co. January 13, 1970.
GENERAL
Shreve, R.N. Chemical Progress Industries, 3rd Edition, New York.
McGraw Hill Book Co., 1967. p. 350-351.
Landau, R. and R. Rosen. Fluorine Disposal. Industrial and Engineering
Chemistry. 40:1389, 1948.
Lunde, K.E. Performance of Equipment for Control of Fluoride
Emissions. Industrial and Engineering Chemistry. 50:293-298,
March 1958.
Rudge, A.J. The Manufacture of Fluoride and Its Compounds. New York
Oxford University Press. 1962. p. 10-18.
Faith, L., Keyes and Clark. Industrial Chemicals, 3rd Edition.
New York, Wiley Company. 1965. p. 426-433.
Davenport, S.J. and G.G. Morgis. Bureau of Mines Information Circular
#7687.
Fabel, H.W. Chemical Industries. 66:508-5095 1950.
-------
4-43
4.6 PAINT AND VARNISH
1 p
Process Description '
The manufacture of paint involves the dispersion of a
colored oil or pigment in a vehicle, usually an oil or resin,
followed by the addition of an organic solvent for viscosity
adjustment. Only physical processes of weighing, mixing,
grinding, tinting, thinning and packaging are involved; there are
no chemical reactions. These processes take place in large mixing
tanks at approximately room temperature. Higher temperatures
are also occasionally used depending on the product. Tinting
pigments include lead and titanium oxides, and carbon black.
Thinners and solvents include mineral spirits, turpentine,
naphtha, xylol, etc.
The manufacture of varnish also involves the mixing and
blending of various ingredients to produce a wide range of
products. However, in this case chemical reactions are initiated
by heating, to produce the desired product. Varnish cooking is
accomplished in either open or enclosed gas-fired kettles for
periods of 4 to 16 hours at a temperature of 200-650°F. The.
exact cooking time and temperature vary widely and depend on the
ingredients and desired product.
Emissions, largely in the form of organic compounds, escape
during the cooking process while the chemical reactions, such as
polymerization, esterification and isomerization, and distillation
occur.
-------
4-44
Factors Affecting Emissions
The primary factors affecting emissions from paint manu-
facture are care in handling dry pigments, type of solvents
used, and mixing temperature. Varnish cooking emissions depend on
the cooking temperatures and time, solvent used, degree of tank
enclosure, and type of air pollution controls used.
Emissions
In the manufacture of paint, about 1 to 2% of the solvents are
2 3
lost even under well controlled conditions. ' Particulate emissions
4
amount to 0.5 to 1% of the pigment handled.
Emissions from varnish cooking amount to 1 to 6% of the raw
material and consist of both gaseous and condensed organic compounds.
Particle sizes in the 8 to 10 micron size range have been measured.
Table 4.6-1 lists the types of compounds which may be emitted from
various varnish manufacturing operations.
Table 4.6-1.
Typical Varnish Raw Materials and
Emissions During Cooking?
RAW MATERIAL
Bodying
Oils
Running
Natural Gums
Manufacturing
Oleoresinous
Varnish
Manufacturing
Alkyd
Varnish
EMISSIONS
J:
f
Water Vapor
Fatty Acids
Glycerine
Acrolein
Aldehydes
Ketones
Carbon Dioxide
Water Vapor
Fatty Acids
Terpenes
Terpene Oils
Tar
Water Vapor
Fatty Acids
Glycerine
Acrolein
Phenols
Aldehydes
Ketones
Terpene Oils
Terpenes
Carbon Dioxide
Water Vapor
Fatty Acids
Glycerine
Phthalic Anhydride
Carbon Dioxide
-------
4-45
Based on information summarized in Appendix 4.6, the
emission factors in Table 4.6-2 were developed.
Table 4.6-2. Uncontrolled Emission Factors for Paint
and Varnish Manufacturingb
Parti culates
Hydrocarbons'
PAINT
2 (1-4) Ibs/ton of pigment
30 (10-40) Ibs/ton of paint
Type of Varnish
Bodying Oil
01eoresinous
Alkyd
Acrylic
VARNISH
Emission, Ibs/ton of varnish'
40 (20-60)
150 (60-240)
160 (80-240)
20
a) Expressed as undefined organic compounds whose composition
depends on the type of varnish or paint.
b) Control techniques used to reduce hydrocarbons include
condensers and/or adsorbers on solvent handling operations,
and scrubbers and afterburners on cooking operations. After-
burners can reduce gaseous hydrocarbon emissions by 99% and
particulates by about 90%. 1 A water spray and oil -niter
system reduce particulate emissions from paint blending by
90%.
Reliability of Emission Factors
These factors are questionable due to lack of new data or
source tests. The reported emissions are based on estimates or
measurements of process weight loss and are considered to be all
-------
4-46
atmospheric losses. Table 4.6-3 presents the factor ranking.
The major assumption inherent in these factors is that the
emissions as determined by process weight losses are essentially
all atmospheric losses.
Table 4.6-3. Emission Factor Ranking for Paint
Emission Data
0-20
8
and Varnish
Process Data
0-10
5
Manufacture
Engineering Analysis
0-10
5
Total
18
-------
4-47
APPENDIX 4.6
Emission Data from literature:
Paint Mixing and Blending
Type of Emission - Quantity Reference
Particulates 1-4 Ibs/ton of pigment 3, 4
0.5-1.7 Ibs/ton after a water 6
spray and filter
Hydrocarbons 20-40 Ibs/ton of paint 4
36 Ibs/ton of paint 5
1-2% of solvent (20-40 Ibs/ton) 2
10 Ibs/ton of paint 7
Varnish (Reference 2)
Hydrocarbons, Ibs/ton of varnish Type of Varnish
range average
20-60 40 Bodying Oils
60-240 150 Oleoresinous
80-240 160 Alkyd
20 - Acryli c
1-5% 3% or 60 Ibs/ton - (Reference 1)
Note: Paints weigh 10-15 pounds/gallon; varnish weighs about
7 pounds/gallon.
-------
4-48
REFERENCES 4.6
Chatfield, H. E. Varnish Cookers. In: Air Pollution
Engineering Manual. Danielson, J. A. (ed.) National
Air Pollution Control Administration. Raleigh, N.C.
Public Health Service Publication. 999-AP-40. 1967.
p. 688-695.
Stenburg, R. L. Atmospheric Emissions from Paint and
Varnish Operations. Paint and Varnish Production.
p. 61-65 and 111-114, September, 1959.
Personal Communication. National Paint, Varnish, and
Lacquer Assoc. September, 1969.
Engineering Estimates Based on Plant Visits in Washington,
D.C. Area by Resources Research, Inc. October, 1969.
Lunche, E. G., et al. Distribution Survey of Products
Emitting Organic Vapors in Los Angeles County. Chem. Eng.
Progress. 53, August, 1957.
Private Communication. 6. Sallee, Midwest Research Insititue.
December 17, 1969.
Communication with Roger Higgins, Benjamin Moore Paint Co.
June 25, 1968, As reported in Draft report of Control Techniques
for Hydrocarbon Air Pollutants. Section 7.4, National Air
Pollution Control Administration, August, 1969.
-------
4-49
GENERAL REFERENCES
Chass, R. L., C. V. Kanter, and J. H. Elliott. Contributions
of Solvents to Air Pollution and Methods for Controlling the
Emissions. J. Air Pollution Control Assoc. 13:64-72, February,
1963.
Brewer, G. L. Odor Control for. Kettle Cooking. J. Air Pollution
Control Assoc. 13:167-169, April 1963.
A Survey of Organic Vapor Emissions in L.A. County. Los Angeles
Air Pollution Control District. September 1959.
McCabe, L. and J. S. Lagarias. Air Pollution in the Paint
Industry. J. of Paint Technology. 1966.
Fink, G. K. and J. E. Weigel. Oxygenated Solvents. Paint
and Varnish Production. March 1968.
Elder, H. J. and A. D. Muldoon. Solvents Emission Survey for
Allegheny County, 1968. Allegheny County Health Department, p a.,
Bureau of Air Pollution Control.
-------
4-50
4.7 PLASTICS
Process Description
The manufacture of most resins or plastics begins with the
polymerization or linking of the basic compound (monomer) usualTy
a gas or liquid, into high molecular weight non-crystalline solids.
The manufacture of the basic monomer is not considered part of the
plastics industry and is usually accomplished at a chemical or petro-
chemical plant.
The three largest selling plastics are currently polyethylene,
polystyrene, and polyvinyl chloride. Consumption of some of the
major plastics in 1967 were:
Polyethylene 3632 million Ibs/year
Polyvinyl Chloride 2167
Polystyrene 2110
Phenolics 800
Polypropylene 641
Plastic manufacture of most compounds involves an enclosed reaction
or polymerization step in the presence of a catalyst, a drying step.,
and a final treating and forming step. Two principal types of polymerization
reactions occur in the manufacture of resins or plastics, namely,
condensation and addition reactions. Condensation polymerization
occurs when single molecules or monomers combine to form larger functional
groups with a resulting loss of simple molecules such as water or
alcohol. Addition reactions involve the joining of bonds between like
molecules without the formation of any side products.
-------
4-51
Phenolic and polyester resins such as phenol-formaldehyde are
made via condensation reactions while.polyolefins such as polyethylene,
polyvinyl chlorides, and polystyrene are made by addition reactions.
Most plastics are polymerized or otherwise reacted in stainless
steel or glass-lined vessels, which are completely enclosed, equipped
with a stirring mechanism, and generally contain an integral reflux
condenser. Since most of the reactions are exothermic, cooling coils
are usually required. Some resins, especially those formed by
condensation reactions, require that the kettle be under vacuum
during part of the cycle. This can be supplied either by a vacuum
pump or by a steam or water jet ejector. Alternatively, the addition
reactions usually occur at elevated temperatures and pressures.
The following process description for polyvinyl chloride (PVC)
also shown in Figure 4.7-1, will illustrate the steps involved in
2 3
making many types of plastics. '
The vinyl chloride monomer is purified by scrubbing and
distillation, (the monomer is shipped with an inhibitor
such as phenol to prevent polymerization). The purified
monomer is then stored at 60°F at 50 psig before charging
to the reactor. The polymerization addition reaction is
carried out in a 3000 - 4000 gallon batch reaction at a
temperature of 100 - 160°F and a pressure of 80 - 180 psig
in the presence of organic peroxide, persulfate, or metallic
chloride catalysts. Reaction time varies from 12 to 72 hours
depending on the reaction conditions, desired product, and
yield. The reactor contents are then stripped of unreacted
monomer by applying a vacuum, and.the polymerized slurry is
dried in a spray dryer or dewatered and dried in a rotary
dryer. Unreacted monomer is recycled. Particle size of the
finished product varies from 0.1 to 1 micron and is further
processed by adding plasticizers, stabilizers, etc.
Treatment of the resin after polymerization varies with the
proposed use. Resins for moldings are dried and crushed or ground
into molding powder. Resins, such as the alkyd resins, to be used for
protective coatings are normally transferred to an agitated thinning
tank, where they are thinned with some type of solvent and then stored
in large steel tanks equipped with water-cooled condensers to prevent
loss of solvent to the atmosphere. Still other resins are stored in
latex form as they come from the kettle.
-------
Vacuum
Purified Vinyl Chloride
Reactor
a.
a
CO
Product
to sizing 6>
packing
Rotary
Dryer
on
ro
Figure 4.7-1. Typical Flow Diagram for Polyvinyl Chloride Manufacture
-------
4-53
Because of the many types of raw materials, ranging from gases
to solids, storage facilities vary accordingly. Ethylene is handled
under pressure; vinyl chloride, a gas at standard conditions, is
liquefied easily under pressure and is stored as a liquid in a pressurized
vessel. Most of the other liquid monomers do not present any
particular storage problems. Some, such as styrene, must be stored
under an inert atmosphere to prevent premature polymerization. Some
of the more volatile materials are stored in cooled tanks to prevent
excessive vapor loss. Some of the materials have strong odors, and
care must be taken to prevent emission odors to the atmosphere.
Solids, such as phthalic anhydride, are usually packaged and stored
in bags or fiber drums.
The major sources of possible air contamination in plastic
manufacturing are the emissions of raw materials or monomer to the
atmosphere, emissions of solvent or other volatile liquids during
the reaction, emissions of sublimed solids such as phthalic anhydride
in alykd production, emissions of solvents during storage and handling
of thinned resins. Table 4.7-1 lists the most probable types and
sources of air contaminants from various plastic manufacturing
operations.
Table 4.7-1. Plastic Manufacturing Emissions and Sources
Plastic Emission Source
Phenolic Resins Aldehydes Storage, leaks,
condenser outlets
Amino Resins Aldehydes Storage and leaks
Polyesters Oil cooking odors, Cooker discharge,
phthalic anhydride, condenser discharge
solvents
Polyvinyl Acetate Odors, solvents Storage, condenser
outlets
Polyvinyl Chloride Odors Leaks
Polystyrene Odors Leaks
Polyurethane Toluene, Odor Product
-------
4-54
Much of the emission control equipment used in this industry is
really a basic part of the system and serves to recover a reactant
or product. These controls include: floating roof tanks or vapor
recovery systems on volatile material storage units, vapor recovery
systems (adsorption or condensers), purge lines and relief valves which
vent to a flare system; and recovery systems on vacuum exhaust lines.
Factors Affecting Emissions
The major factor affecting atmospheric emissions is the basic
design of the plant, its maintenance, and the amount of control
equipment included in the basic plant. Greater emissions may be
expected from those processes operating at atmospheric pressure since
condensers then vent directly to the atmosphere, and care in sealing
the reactor is not generally as great.
Emissions
Quantitative emission data from plastics manufacturing are not
readily available. In the manufacture of ethylene gas (a high pressure
process) hydrocarbon emissions amounted to 0.21% (4.2 Ibs/ton) of the
feed. 5 Other reported data,.from manufacturing plant estimates based
largely on material balance estimates, are shown in Table 4.7-2. '
Table 4.7-2. Estimated Emissions From Plastics Manufacturing. Ibs/ton
Plastic Gasesb Particulate
Polyvinyl Chloride 17 35a
Polypropylene 0.7 3
General 5 to 10
a) Usually controlled with a fabric filter, efficiency of 98-99%.
b) Reported as the monomer (vinyl chloride, or propylenes etc.).
-------
4-55
This wide range in emission data is due to the difficulty in
accurately performing material balance estimates, and to actual emission
differences.
Based on the reported emissions from ethylene manufacture and
the two estimates in Table 4.7-2, a general gaseous emission factor
of about 5-10 Ibs/ton of feed may be used until better data are
available.
Reliability of Emission Factor
Due to the limited data available and the wide variation in
processing methods and products, the emission factor for plastics
manufacturing must be classified as questionable. Table 4.7-3 presents
the factor ranking.
Table 4.7-3. Emission Factor Ranking
Emission Data 'Process Data Engineering Analysis Total
0-20 0-10 0-10
-------
4-56
REFERENCES 4.7
1. Modern Plastics Encyclopedia. 1968-1969, p. 46-47.
2. Shreve, R.N. (ed.). Chemical Process Industries. New York,
McGraw-Hill Book Company, 1967. p. 660-673.
3. Anon. Drying Tricks Tailor Resin Properties. Chem. Eng.
66_:166-169, November 16, 1959.
4. Chatfield, H.E. Resin Kettles, In: Air Pollution Engineering
Manual, Danielson, J.A. (ed.). National Air Pollution Control
Administration, Raleigh, North Carolina, Public Health Service
Publication 999-AP-40, 1967. p. 687.
5. Mencher, S.K. Change Your Process to Alleviate Your Pollution
Problems. Petro/Chem Eng. 39_:(6): 21-24, May 1967.
6. Communication with M. McGraw. National Air Pollution Control
Administration, Division of Air Quality and Emission Data.
December 1969.
7. Communication with Maryland State Department of Health,
November 1969.
GENERAL REFERENCES
Sittig, M. Organic Chemical Process Encyclopedia. Park Ridge,
New Jersey, Noyes Development Corporation, 1969. p. 545-569.
Parker, C. H. Plastics and Air Pollution. SPE Journal.
p. 26-30. December 1967.
-------
4-57
4.8 PRINTING INK
Process Description
Ink is a fluid or viscous material of various colors, but most
often black, used for writing and printing. Printing inks as supplied
to the graphic arts industry are used in much greater volume as
compared to writing inks. There are approximately 350 printing-ink
manufacturing establishments in the United States today with a
production value of over $300 million in 1968.
Printing ink is a mixture of coloring matter, dispersed or
dissolved in a vehicle or carrier, which forms a fluid or paste which
can then be printed on a substrate and dried. The coloring agents
used are most often pigments, toners and dyes, or combinations of
these materials. These agents are selected to provide color contrast
with the background on which the ink is printed. The vehicle used
acts as a carrier for the colorant during the printing operation.
2
In most cases the vehicle serves to bind the colorant to the substrate.
Drying oils, petroleum oils, and resins are usually employed as
vehicles. However, newer synthetic-resins are becoming increasingly
popular because they are quick-drying and have better working
properties.
There are four major classes of printing ink. These vary
considerably in physical appearance, composition, method of application,
and drying mechanism. The four classes are letterpress and
lithographic inks, commonly called oil or paste inks; and
flexographic and rotogravure inks, which are referred to as solvent inks.
-------
4-58
Flexographic and rotogravure inks have many elements in common
with the paste inks, but differ in that they are of very low
viscosity, and they almost always dry by evaporation of highly
volatile solvents.
There are three general processes in the manufacture of printing
inks, namely:
1) Cooking the vehicle and adding dyes
2) Grinding of a pigment in a vehicle using a roller mill
3) Replacing water in the wet pigment pulp by an ink
vehicle (commonly known as the flushing process).
The ink "varnish" or vehicle consists of resins, drying oils,
and/or petroleum oils. This varnish is generally cooked in large
kettles at 200-600°F for an average of 8-12 hours in much the same
way that regular varnish is made. Most modern kettles are totally
enclosed stationary vessels; however, there are still a number of
mobile, open kettles being used. Cooking the varnish performs many
functions, depending upon the raw materials used and the formulation
4
cycle. These functions include:
1) Polymerization of the oil
2) Depolymerization of the high molecular weight resins at
600 to 650°F
3) Melting and accelerated solution of any solids
4) Esterfication at 450° - 525°F
5) Isomerization
6) Distillation and evaporation
Letterpress, litho, and dry-offset inks are produced in two ways:
1) By mixing preground or flushed pigment concentrates with
vehicles, solvents, oils, and compounds.
2) By mixing dry pigments with vehicles and compounds and then
grinding them on ink mills.
Some typical ink formulas are given in Table 4.8-1.
-------
4-59
Table 4.8-1 Typical Ink Formulas'
Letterpress Newsprint Black
10 or 15a carbon black
2 or 3 induline toner
85 or 67 mineral oil
3 or 15 mineral oil (low
viscosity)
Quick-Set Litho Black
16 or 18 carbon black
4 or 6 alkali blue toner
65 or 58 phenolic resin/oil
(hydrocarbon solvent,
530°F)
10 or 6 bodied linseed oil
2 or 2 cobalt linoleate
5 or 10 aliphatic hydrocarbon
solvent (530°F)
Heat-Set Publication Blue
10 phthalocyanine blue
15 alumina hydrate
65 pentaerythritol resin
ester/hydrocarbon solvent
5 polyethylene wax compound
5 aliphatic hydrocarbon
solvent (470°F)
Gloss Letterpress Oleoresinous Red
25 permanent 2B red
5 clay or alumina hydrate
50 phenolic resin/China wood oil
15.5 ester gum/linseed oil
2 cobalt naphthenate
2 lead naphthenate
0.5 eugenol
a) Numbers refer to proportions by weight in mixture.
Mixing of the pigment and vehicle is done in dough mixers of
various sizes, or in large agitated tanks which may hold up to 1000
pounds. Grinding is most often carried out in three-roller or five-
roller horizontal or vertical mills. Softer, more fluid inks can be
ground in colloid mills, sand mills, or ball mills. Dispersion of
the pigment in the roller mills is accomplished by shearing forces
generated by the differential speed of the rollers as well as by the
closeness of roller setting.
Flexographic and rotogravure printing processes require the use
of volatile solvents such as low boiling point alcohols, esters,
aliphatic and aromatic hydrocarbons, ketones, and water.
-------
4-60
Factors Affecting Emission
The quantity, composition, and rate of emissions depend upon the
ingredients in the cook, the cooking temperature and time, the method
of introducing additives, the degree of stirring, and the extent of
4
air or inert gas blowing.
Particulate emissions resulting from the addition of pigments
to the vehicle are affected by the type of pigment and its particle
size. Carbon black handling generally causes the biggest particulate
problem, and efforts are always made to control this emission with
fabric filters.
Emissions
Varnish or vehicle preparation by heating is by far the largest
source of ink manufacturing emissions. Cooling the varnish components--
resins, drying oils, petroleum oils, and solventsproduces odorous
emissions which are very objectionable. At about 350°F the products
begin to decompose, resulting in the emission of decomposition
products from the cooking vessel. Emissions continue throughout
the cooking process with the maximum rate of emissions occurring
just after the maximum temperature has been reached.
Compounds emitted from cooking of oleoresinous (resin plus
varnish) varnish include water vapor, fatty acids, glycerine, acrolein,
phenols, aldehydes, ketones, terpene oils, terpenes, and carbon
A
dioxide. Some highly offensive sulfur compounds such as hydrogen sulfide,
allyl sulfide, butyl mercaptan, and thiphene are formed when tall
oil is used in the ink vehicle.
Emissions of thinning solvents used in flexographic and rotogravure
inks may also occur. In most of the newer installations, the cooked
varnish is pumped to a thinning tank that is equipped with integral
condensers and emissions are kept to a minimum. In the older open-
kettle operations, however, the thinning operation is carried out
near the boiling point of the solvent, and emissions of vapor can be
considerable.
-------
4-61
Quantitative emission data from ink manufacturing were not found.
However, based on published emissions from similar processes such
as paint and varnish manufacturing, and discussions with a manufacturer,
the factors in Table 4.8-2 were derived. This information is based on
information in Chapter 4.6, and no appendix is included in this chapter.
Table 4.8-2. Emissions From Printing Ink Manufacturing
Process Gaseous Organicsa Particulate
Tbs/ton Ibs/ton
Vehicle Cooking
General 120
Oils 40 (20-60)
Oleoresinous 150 (60-240)
Alkyds 160 (80-240)
Pigment Mixing 2 (1-4)
a) Emitted as a gas, but rapidly condense as the effluent is
cooled, see Reference 6 and 7.
b) Based on Reference 7.
Emissions from the cooking phase can be reduced by more than 90%
4 5
with the use of scrubbers or condensers, followed by afterburners. '
Reliability of Emission Factors
Due to a lack of measured emission data, these factors for ink
manufacture must be considered questionable. Table 4.8-3 presents
the factor ranking.
Table 4.8-3. Emission Factor Ranking for Printing Ink Manufacture
Emission Data Process Data Engineering Analysis Total
0-20 0-10 0-10
0 5 38
The current National Air Pollution Control Administration study
on printing processes will cover the manufacture of ink, and should
Q
provide more quantitative data when it is completed in 1970.
-------
4-62
REFERENCES 4.8
1. Larsen, L.M. Industrial Printing Inks. New York, Reinhold Pub.
Co., 1962.
2. Inks, Kirk - Othmer Encyclopedia of Chemical Technology. (2nd Edition)
1966, p. 611.
3. Shreve, R.N. Chemical Process Industries (2nd Edition). New York,
McGraw-Hill Book Company, 1967. p. 454-455.
4. Chatfield, H.E. In: Air Pollution Engineering Manual, Danielson,, J.A.
(ed). National Air Pollution Control Administration, Raleiah, N*C.
Public.Health Service Publication 999-A-P-40-1967. p. 688-695.
5. Private Communication with Interchemical Corp., Ink Division,
Cincinnati, Ohio. November TO, 1969.
6. Stenburg, R.L. Atmospheric Emissions from Paint and Varnish
Operations. Paint and Varnish Production, p. 61-65 and 111-114.
September 1959.
7. Supra, 4.6.
8. Private Communication with L. Lasker. Process Control Engineers D,dv.,
National Air Pollution Control Administration, Cincinnati, Ohio.
October 1969.
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4-63
4.9 SOAP AND DETERGENTS
Process Description
The manufacture of detergents generally begins with the sulfonation
by sulfuric acid of a fatty alcohol or linear alkylate. The sulfonated
compound is then neutralized with caustic solution (NaOH), and various
1 2
dyes, perfumes, and other compounds are added. The resulting paste or
slurry containing 40 - 60% water is then sprayed under pressure into a
vertical drying tower where it is dried with a stream of hot (400 - 500°F)
air passing upward through the falling droplets, as shown in Figure 4.9-1,
The dried detergent is then cooled and packaged. The main source of
particulate emission is the spray drying tower, since the exit gases contain
entrained particles. Odors may also be emitted from this source and from
storage and mixing tanks.
The manufacture of soap entails the catalytic hydrolysis of various
fatty acids or glycerides, such as stearic, oleic, palmitic, etc., with
sodium or potassium hydroxide to form a glycerol-soap mixture. This mixture
is separated by distillation, neutralized and blended to produce soap. The
finished soap may be in a bar, flake, or powder form. The main atmospheric
pollution problem in the manufacture of soap is odor, and if a spray drier
is used a particulate emission problem may also occur. Vent lines, vacuum
exhausts, product and raw material storage, and waste streams are all
potential odor sources.
Depending on the type of soap or fatty acid used and the required
pretreatment of the raw materials, a variety of odors could be emitted.
Nitrogen containing compounds such as soya bean, soap stock, or cottonseed
stock produce amine compounds which have an objectionable fishy odor.
Control of these compounds may be achieved by scrubbing all exhaust fumes
and if necessary incinerating the remaining compounds. Odors emanating
o
from the spray drier may be scrubbed with an acid solution to control odors.
-------
Spray Chamber
Packed Scrubber
Venturi Scrubber
4
|
E = 7
E = 4.5
E = 2.7
1 E = I3.5
Secondary
Collector
Primary Collector
(cyclone)
Fines to Process
t
Slurry Feed
Dry Product
E = Emission in Ibs. per
ton of product
i.
E =0.17
~L
Primary
Separator
/o
Air Conveyor
Secondary
Collector
Fines to Process
Figure 4.9-1 Process Flow and Particulate Emissions from Detergent Manufacturing.
-------
4-65
Factors Affecting Emissions
In the manufacture of soap and detergents, particulate emissions
from the spray dryer are affected by the basic design of the unit, the desired
product (especially its size), and the type of control equipment and process
throughput. Odor emissions are affected by the type of raw materials used,
the basic equipment design such as reactor volume and condenser capacity, and
product throughput.
Emissions
Particulate emissions from spray drying operations are shown in
Figure 4.9-1 and summarized in Table 4.9-1. More detailed emission information
is presented in the Appendix.
Table 4.9-1. Particulate Emissions From Detergent Spray Drying.
Control Device Overall Efficiency, % Emissions, Ibs/ton
of Product
None - 90 (72-108)
Cyclone a 85 13.5
Cyclone Followed By:
1. Spray Chamber 92 7
2. Packed Scrubber 95 4.5
3. Venturi Scrubbe*- 97 2.7
a Some type of primary col "ie-lor such as a cyclone is considered an integral part
of the spray drying sy:;t,p'.
Other dust emissions from cooling and packaging amount to about 0.17
Ib per ton of product.
The size distribution of the particulate emissions leaving the spray
dryers before any collection equipment is shown in Figure 4.9-2.
While the above j-.itd were obtained for detergent manufacturing operations,
they can, if no other dst-i are available, be used for soap manufacturing
operations which use r-pr«y urye-rs.
-------
100
0.
-pi
CT>
10 50 90
%BY WEIGHT LESS THAN STATED SIZE
99.99
Figure 4.9-2 Particle size distribution of spray dryer emissions4.
-------
4-67
Emissions of odorous organic compounds also occur, but no
emission information is available and the emissions cannot be estimated
because of the many variables involved. Carbon monoxide emissions do not
occur from these manufacturing processes.
Reliability of Factor
Fair agreement between calculated values and the single reported
field measurement for particulate matter was obtained. Based on the
ranking procedure in Table 4.9-2, the particulate emission factor is
felt to be good. However, there is room for improvement; and additional
emission data, especially for gases, are required.
Table 4.9-2. Detergent Manufacturing Emission Factor Ranking
Emission
Data
0-20
8
Process
Data
0-10
"*«-» *>'.* ***. , ^
8
Engineering
Analysis
0-10
8
Total
24
No major assumptions were involved in determining these emission
factors. Minor assumptions required to use various reported bits of
information were:
1) 10% of air in leakage around dryer outlet (this increased
emission from 70 to 77 Ibs/ton).
2) 15% organic content in emission (this could affect the
calculated value of 10.4 Ibs/ton after a cyclone by ± 10%).
These assumptions give estimated emissions well within the
overall range of final results.
-------
4-68
APPENDIX 4.9
1 5
A. Calculation of Gas Volumes From Spray Dryer *
1) Air entering at 70°F and 50% relative humidity contains about
40 grains HO per 1b dry air or 0.0057/lb dry air, and is heated
to about 450°F.
2) Exit air is at 250°F and 140°F Wet Bulb Temp, and contains 0.13 Tb
H20/lb dry air (from high temperatures psychrometric chart).
Therefore, each Ib of dry air entering system picks up 0.13 Ibs of
H20. The exit gas temperature may be as low as 200°F. This would*
increase the moisture content by about 10%.
3) Pounds of dry air required per 1000# of finished product based on
40% water in detergent slurry (1667 Ibs of slurry) is:
667 1b H2° = 5120 Ib dry air required
0.13 Ib H20/lb dry air
4) Exit volume in SCF G>70°F 29.92 "H is:
5120 Ib air x 387 ft3/lb mol = 68,325 ft3 dry air
29 Ib/mol
667 Ib H20 x 387. = 14,340 ft3 water vapor
18 TOTAL = 82,665aft3 moist air per
1000 Ib product
at 70°F.
Assume 10% in leakage of outside air, or 90,000 ft3 total air per
1000 Ib of product. This is the same as 180,000 ft3 per ton of product.
5) Based on grain loadings reported by Phelps , the Ibs of particu.Ta.te
emitted per ton of product may be calculated as follows:
Leaving dryer - 3 grs/ft3 x 180,000 ft3 x 1 = 77 Ibs/ton
ton 7000 grs/lb
Larson reported an emission of 8.8 Ibs/ton of product of non-ether
soluble particulate following a cyclone collector on a detergent spray dryer.^
Heavy duty detergents with controlled sudsers contain 8 - 20% organic
o
surfactants. Using 15% as the average organic fraction, the total particulate
emission would be 8.8/.S5 or 10.4 Ibs/ton after a cyclone collector.
a) Based on humid volume of 21.5 ft3/lb dry air at 250°F, 5120 Ib dry air
x 21.5 ft3 x 530°R = 82,000 ft3 moist volume at 70°F.
Ib dry air 710°R
-------
4-69
A 90% efficient cyclone would mean the inlet loading was 104 Ibs/ton (10.4);
( -10)
an 80% cyclone would give 52 Ibs/ton.
Data from Reference 7 showed uncontrolled emission rates of 125 Ibs/ton
of product each from two installations with emissions reduced by cyclone-scrubber
combinations to 5 Ib/ton and 1.5 Ib/ton,respectively.
An average of these sources of data yields an uncontrolled particulate
emission rate of from about 75 to 125 with a most probable value of about
90 Ibs/ton. This figure is always reduced by at least a cyclone type collector,
and usually by other more efficient secondary collectors.
Based on Phelps1 data and knowing efficiencies of various types of
collectors, the following emission data were computed:
COLLECTOR EFFICIENCY, % FACTOR
Increment Overal1 Ibs/ton,
Uncontrolled (right 0 90 (75-125)
. from tower)
Primary Cyclone 85 85 13.5
Secondary Device In 50 92.5 6.7
Series Spray Chamber
Secondary Scrubber - - 65 94.7 4.7
Venturi Scrubber 80 97 2.7
From Conveying of Dry Product
One cfm of air is used for each Ib/hr of product. For 1 ton
of product/hr., 2000 cfm are therefore required. Exit loss after primary
3 1
inertial device (cyclone) and a bag collector is 0.01 grs/ft. or less.
2000 ft.3 x 60 min. x 0.01 grs x 1 _ Q 1?1 lbs/hr
min. hr. ft.3 7000 grs/lb
or 0.17 Ibs/ton or less
-------
4-70
REFERENCES 4.9
1. Phelps, A. H. Air Pollution Aspects of Soap and Detergent
Manufacture. J. Air Pollution Control Association. 17:505-507,
August 1967.
2. Shreve, R. N., (ed.). Chemical Process Industries, 3rd Edition,
New York McGraw-Hill Book Company. 1967. p. 544-563.
3. Molos, J. E. Control of Odors From A Continuous Soap Making
Process. J. Air Pollution Control Association. 11:9-13, 44,
January 1961.
4. Duprey, R. L. Particulate Emission and Size Distribution.
National Air Pollution Control Administration, Raleigh, N. C.
Unpublished Report for New York - New Jersey Air Pollution
Abatement Activity, May 1967.
5. McCormick, P. Y., R. L. Lucas, and D. F. Wells. Gas-Solid
Systems. In: Chemical Engineer's Handbook, Perry, J. H. (ed.).
New York, McGraw-Hill Book Company, 1963. Chapter 20, p. 59.
6. Larson, G. P. Evaluating Sources of Air Pollution. Industrial
and Eng. Chem. 45_: 1070-1074, May 1953.
7. Private Communication. Maryland State Department of Health,
November, 1969.
GENERAL REFERENCES
Fedor, et al. Industrial and Eng. Chem. 5J_:13, January 1959.
Phelps, A. H. What Doesn't Go Up Must Come Down. Chem. Eng.
Progress. 62_: 37-40, October, 1966.
Murray, R. C. and E. J. Vincent. Soaps and Synthetic Detergents,
In: Air Pollution Engineering Manual, Daniel, J. A., (ed.).
Raleigh, North Carolina, National Air Pollution Control
Administration, Public Health Service Publication 999-AP-40,
p. 716-720.
-------
4-71
4.10 SYNTHETIC RUBBER
1 2
Process Description *
Copolymers of butadiene and styrene commonly known as SBR
account for more than 70% of all synthetic rubber produced in the
United States.
The manufacture of synthetic rubber and plastics (Section 4.7)
are similar. In a typical SBR manufacturing process, the monomers
of butadiene and styrene are mixed in a ratio of about 3:1;
various additives such as soaps and mercaptans are added, and the
mixture is polymerized to approximately a 60% conversion point.
A cumene peroxide which acts as a polymerization catalyst is also
added. Approximatley 680 pounds of butadiene and 212 pounds of
styrene are required to produce 1,000 pounds of product. This
mixture is cooled before being charged to the reactor. The
polymerization*.reaction takes place at about 40°F and at essentially
atmospheric pressure for 8-16 hours. When conversion reaches about
60%, the reactor contents are dumped into flash drums or blow-down
tanks. Unreacted butadiene is evolved from the latex mixture in the
flashing process and returned to the process. Unreacted styrene
is removed in a stripping column operated under vacuum and also
returned to the process. The latex product is then mixed with various
ingredients such as oil, carbon black, etc.; coagulated and precipitated
from the latex emulsion. The rubber particles are then dried and
baled. Drying operations may take many forms depending on the desired
product. Spray dryers, vacuum dryers, and tunnel or conveyor
dryers have been used.
-------
4-72
Emissions from synthetic rubber manufacturing process consist
of organic compounds, largely the monomers used, emitted from the
reactor and blow-down tanks, and particulate matter and odors from
the drying operations.
Drying operations are frequently controlled with fabric filter
systems to recover any particulate emissions since this emission
represents a product loss. Potential gaseous emissions are largely
controlled by recycling the gas stream back to the process.
Factors.Affecting Emissions
The overall condition and equipment maintenance at the plant,
the overall yield, the degree of monomer recovery, and the degree
of control applied to vacuum vents and dryer operations all affect
emissions. The largest single factor is the degree of control used
on the blow-down tank vents and on the stripping tower.
Emissions
Gaseous emissions consisting mainly of the monomer compounds used
to make the rubber, account for the largest portion of emissions.
Table 4.10-1 presents the emissions from a butadiene-acrylonitrile and
o
butadiene-styrene rubber manufacturing plant.
-------
4-73
Table 4.10-1 Emissions from Synthetic Rubber Plant (Butadiene-Acrylonitrile
and Butadiene-Styrene)3
Compound Quantity Emitted,
tons per year
1,3- Butadiene 500a
2 - Methyl Propene 180
1 - Butyne 36
1,4- Pentadiene 15
Total Alkenes 753
3, 4 - Dimethyl heptane 15
Cis - 2 - Pentane 29
Total Alkanes 44
Ethanenitrile (Alaphatic) 10
Acrylonitrile 210
Aerolein (Propenal) 31
Total Carbonyls 24T
a) The butadiene emission is not continuous and is greatest right after
a batch of partially polymerized latex enters the blowdown tanks.
While the data in Table 4.10-1 were based on measured emission
rates, no relationship to plant production was made and a usable
emission factor based on pounds per ton is thus not obtainable. The
table does, however, show the types of compounds that are emitted.
Reported emissions from another rubber plant showed 0.55 pound
of particulate, 40 pounds of butadiene, and 17 pounds acrylonitrile
4
per ton of product. These emissions are comparable to those reported
in Table 4.10-1 for a 25,000 ton per year plant.
-------
4-74
Reliability of Emission Factor
Due to the many variables in the synthetic rubber manufacturing
process and the limited emission data available, the emission factor
is questionable. Table 4.10-2 presents the factor ranking.
Table 4.10-2. Emission Factor Ranking
Emission Data Process Data Engineering Analysis Total
0-20 0-10 0-10
45 2 lil
Additional emission measurements are required to assess the
quantity and composition of emissions from synthetic rubber manufacturing
processes.
-------
4-75
REFERENCES 4.10
Shreve, R.N. Chemical Process Industries, 3rd Edition. New York.
McGraw-Hill" Book Company. 1967. p. 720-730.
Sittig, M. Organic Chemical Process Encyclopedia, 2nd Edition.
Park Ridge, New Jersey. Noyes Development Corporation. 1969.
p. 123.
Anon. The Louisville Air Pollution Study. Public Health Service,
Division of Air Pollution, Robert A. Taft Sanitary Engineering
Center, Cincinnati, Ohio. 1961. p. 26-27, 124.
Communication with M. McGraw. National Air Pollution Control
Administration, Division of Air Quality and Emission Data.
December 2, 1969.
GENERAL REFERENCES
Labine, R.A. Flexible Process Makes Silicone Rubber.
Chem. Eng. 67_:102-105, July 11, 1960.
Labine, R.A. Butyl Process Spurs French Economic Boom.
Chem. Eng. 66;60-63, November 30, 1959.
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4-76
4.11 SYNTHETIC FIBERS
.Process Description
Fibers are either natural, semi-synthetic, or "true" synthetic.
Natural fibers are produced from naturally found materials such as
cotton or wool. Semi-synthetics (e.g.,viscose rayon and acetate
fibers) result when natural polymeric materials such as cellulose
are brought into a dissolved or dispersed state and then spun into
fine filaments. True synthetic polymers, such as nylon, orlon and
dacron resul-t from two methods of forming long chain molecules:
addition polymerization and condensation polymerization. United States
annual production of synthetic and semi-synthetic fibers is now
more than 3 billion pounds.
Some of the major synthetic (true and semi-synthetic) fibers
are classified chemically and by method of spinning in Table 4.11-1.
All true synthetic fibers begin with the preparation of extremely
long, chainlIke molecules. The polymer is spun in one of four
3
ways: 1) melt spinning - involves pumping molten polymer through
spinneret jets. The polymer solidifies into filaments as it strikes
the cool air. 2) dry spinning - the polymer is dissolved in a
suitable organic solvent, and the resulting solution is forced through
spinnerets. Dry filaments result upon the evaporation of the
solvent in warm air. 3) wet spinning - the solution is coagulated
in a chemical bath as it emerges from the spinneret. 4) core spinning
newest method - a continuous filament yarn together with short-
length "hard" fibers are introduced onto a spinning frame in such a
way that a composite yarn is formed in which the continuous filament
p
is a core and the stable fibers are a sheath.
-------
4-77
Table 4.11-1. Types of Fibers and Films
Classification Spinning Method
Polyamides, or nylon fibers
Nylon 66, nylon 6 Melt
HT-1, or Nomex Dry
Polyesters
Fibers: Dacron, Vycron, Kodel, Fortrel Melt
Films: Mylar, Gronar, Kodar, Estar Melt
Acrylics and modacrylics
Orion fiber Dry
Acrilan fiber Wet
Creslan fiber Wet
Dynel fiber (vinyl-acrylic) Dry
Verel fiber Dry
Vinyls and Vinylidines
Saran fiber and film Melt
Vinyon N fiber (vinyl and acrylonitrile) Dry
Spandex
Lycra fiber (DuPont) Core
Vyrene fiber (U.S. Rubber) Core
Blue C fiber or film (Chemstrand) Core
Olefins
Polyethylene films
Polypropylene fibers and films: Avisun, Herculon
Fluorocarbons
Teflon
Regenerated cellulose
Fibers: Rayon (viscose), Cordura, cuprammonium Wet
Film: Cellophane Wet
Cellulose Esters
Acetate fibers and films: Acele, Estron Dry
Triacetate fiber: Arnel Dry
-------
4-78
In order to illustrate in more detail the processes involved
in the manufacturing of synthetic fibers .simplified flow charts for
the manufacture of nylon yarn (true synthetic) and viscose rayon
1 2
yarn (semi-synthetic) are shown in Figures 4.11-1 and 4.11-2 ,
respectively. In addition, a brief description of each of these
particular manufacturing processes follows:
Nylon(66): This fiber is made from basically two chemical s--
hexamethylene diamine (HgNfCHgJgNHg) and adipic acid
These compounds are combined to form nylon
salt, hexamethylene dlamonium adipate and polymerized to
polyhexamethylene adipamide or nylon. Emissions of gaseous
hydrocarbons may occur, especially from drying of the finished
fiber. Emission controls are not generally used.
Viscose Rayon: Wood chips or cotton fibers are treated to
produce sheets of purified cellulose. The cellulose sheets
are then soaked in caustic soda, producing sheets of alkali
cellulose, which is broken up into grains called "cellulose
crumbs." The "cellulose crumbs" are aged for two or three
days under controlled temperature and humidity. Liquid carbon
disulfide is then added, which combines with the cellulose crumbs
to form cellulose xanthate. The cellulose xanthate crumbs are
dissolved in a weak solution of caustic soda and transformed into'
a thick viscous solution called viscose. The viscose is aged,
filtered, and vacuum- treated to remove air bubbles. It is then
forced through the holes of a spinneret into sulfuric acid,
which coagulates the cellulose of the soluble cellulose xanthate
to form pure generated cellulose filaments. The filament is
stretched, treated, dried, and wound. Sodium sulfate is a
by-product while carbon disulfide is a major gaseous emission.
Hydrogen sulfide is also emitted.
-------
Hexamethylene
diamine
Adipic
Ac id
Autoclave Evaporator Autoclave Casting
wheel
Chopper
Melting
chamber
Figure 4.11-I Nylon Manufacturing process
-------
4-80
Pulp soaked in caustic
and pressed
i
Shredding &
initial aging
i
Churning & addition
of carbon disulfide
i
Secondary aging
i
Filter press
i
Spinning in
sulfuric acid bath
i
Drying
'Vacuum
Figure 4.11-2 Viscose Rayon Manufacturing
-------
4-81
Air pollution controls are not used to reduce CSp or H2S emissions
in the United States. However, an activated fixed bed carbon absorber
4
has been successfully used in England.
Factors Affecting Emissions
The major factors affecting emissions from synthetic fiber
manufacturing is the type of fiber produced and the manufacturing
process involved, and the volatility of any binder used on the fibers.
Emissions
Very limited emission data are available from synthetic fiber
manufacturing plants. Exit gas stream concentrations of 1000 ppm
CS2 and 30 ppm H2S have been reported for rayon plants.
Table 4.11-2 Emission Factors for Synthetic Fiber Manufacturing
Type of Fiber
Rayon
Nylon
Dacron
Emission
CS2
H2S
Oil Vapor or Mist
Gaseous Hydrocarbons
Oil Vapor or Mist
Quantity, Ibs per ton
*H
a -._
10 to 20b
4 to 10b
4 to 10b
of Fiber
a) May be reduced by 80-95% by adsorption in activated charcoal. Emission
Data Based on Reference 5.
b) Emissions vary with type and volatility of binder - Reference 6.
-------
4-82
Reliability of Emission Factor
Due to the very limited data available on fiber manufacturing,
the emission factors must be considered questionable. Further work
in obtaining both quantity and composition of gaseous emissions is
required and appears warranted due to the growth of this industry.
Table 4.11-3 presents the emission factor ranking.
Table 4.11-3 Emission Factor Ranking for Synthetic Fibers
Emission Data
0-20
Rayon 5
Nylon 5
Process Data
0-10
5
2
Engineering Analysis
0-10
2
2
Total
12
9
Due to the limited amount of information available for synthetic
fiber manufacturing, no Appendix is included in this section.
-------
4-83
REFERENCES 4.11
1. Shreve, R.N. Chemical Process Industries, 3rd Edition. New York,
McGraw-Hill Book Company, 1967. p. 686-709.
2. Labarth, J. Textiles: Origins To Usgae. New York, McMillan Co.,
1964. p. 279-371.
3. Fibers, Man-Made. Kirk-Othmer Encyclopedia of Chemical Technology.
New York, Interscience Publishers, 1965. p. 151-152.
4. Anon. Fluidized Recovery System Nabs Carbon Disulfide. Chemical
Engineering. 7(D(8): 92-94, April 15, 1963.
5. Private Communication. Rayon Manufacturing Plant. December 1969.
6. Private Communication, du Pont Company January 13, 1970.
-------
5. FOOD AND AGRICULTURAL INDUSTRY
Atmospheric emissions from feed and grain handling, meat
smoking, and fermentation processes are reviewed in this section.
In general, these industries are characterized by a lack of
available emission information.
Grain handling is largely based in the midwestern area of the
country. Due to the tremendous quantities of grain handled and the
dry, dusty nature of the material handled, grain handling is a
significant source of particulate emissions.
Continued improvements in meat smoking processes have reduced
the smoke problem from this source.
Quantitative emission data from fermentation processes was not
found. Due to the alternate methods of processing, a wide range in
the emissions can be expected.
-------
5-2
5.1 FEED AND GRAIN MILLS AND ELEVATORS
Process Description
Graift elevators are primarily transfer and storage units and are
classified Into two categories. These are the smaller more numerous
country elevators and the larger terminal elevators. In addition,
many elevator locations also contain feed manufacturing facilities.
Particulat'e emissions occur due to the dry, light nature of most
grains anti the way they are handled via pneumatic and mechanical
conveyors, A wide variety of grain handling configurations are
possible at elevator sites depending on the number and quantity of
grains haniTed, and the amount of processing required to produce
feeds. At ffain elevator locations any or all of the following
operations tan occur:
Receiving, transfer and storage
Cleaning
Drying
Milling or grinding
Receiving and transfer operations are accomplished by unloading
the grai'fi usually by dumping into a bin followed by conveyor belt
or pneumatic transfer. Cleaning operations are designed to eliminate
impurities such as sticks, stones, and other foreign matter. Both
screening and air classifiers are used to separate grain and
foreign 'matter.
Drying is usually accomplished in rotary, column, or shelf
dryers using heated air as the drying medium.
GriMihg may be done in a variety of devices in either a wet or
dry state. Common devices used include hammer mills and rollers.
-------
5-3
Dust control at elevator operations is most commonly accomplished
by cyclones or baghouses. Hooding and ventilation of such dust
generation points as shipping and receiving, conveyor drop, cleaning,
drying, and elevating points accomplishes dust pickup at the source,
with the cyclone and bag filter used to remove dust from the exhausted
air. Cyclones are the most commonly used collectors due to their low
cost and durability under conditions of high temperature and moisture.
Combinations of the two types of collectors are often used for high
efficiency of air cleaning.
Many of the large terminal elevators also process grain at the
same location. The grain processes may include wet and dry milling
(cereals), flour milling, oil seed crushing, and distilling. Wet
milling by its nature is not conducive to major dust formation, although
dust may escape from dryer cyclones. Dry milling, however, is somewhat
more dusty in its operation. Most handling and transfer in these operations
is pneumatic, allowing good dust control. Small particle size makes dust
control a much greater problem. Oil seed crushing generally is not
conducive to major dust generation, but losses can occur from extracting
and drying operations and from cyclone collectors used on these operations.
Grain distilling operations also are not conducive to major dust formation
although particulates can escape during unloading of grains and be entrained
in the gaseous discharge from cooling operations. The major problem at
these operations remains that of odor emissions.
Feed manufacturing involves the receiving, conditioning (drying, sizing,
cleaning) and blending of grains and various nutritional supplements and
their subsequent bagging or bulk loading. Emissions may occur during
receiving and loading operations and from dust collection systems which are
generally applied to most phases of the operation to reduce product and
component losses. Pneumatic conveying is widely used in these processes
for transfer and loading.
-------
5-4
Factors Affecting Emissions
Factors affecting emissions from, grain elevator operations include
the types of grain, the moisture content of the grain (usually 10-30%),
amount of foreign material in the grain (usually 5% or less), the amount
of moisture in the grain at the time of harvest (hardness), the amount
of dirt harvested with the grain, the degree of enclosure at loading
and unloading areas, the type of cleaning and conveying, and the
amount and type of control equipment used, if any.
Factors affecting emission from grain processing operations include
the type of processing (wet or dry), the amount of grain processed,
the amount of cleaning, the degree of drying or heating, the amount
of grinding, the temperature of the process, plus the degree of control
applied to the particulates generated.
Factors affecting emissions from feed manufacturing operations
include the type and amount of grain handled, the degree of drying,
the amount of additive or water blended into the feed, the type of
handling (conveyor or pneumatic), and the degree to which control
equipment is applied to the process.
Emissions
Emissions from feed and grain operations may be separated into
those occurring at all elevators involving transfer losses, and those
emissions occurring at other grain processing operations such as
cleaning, drying, and grinding.
Emissions are greatest at the loading and unloading areas, especially
when these operations are carried out in the open. Most of the
particulate emission is 50p or smaller in size. A particle size
distribution for grain dust emissions is shown in Table 5.1-1.
Beeswings or corn chaff, although a small weight percent of the emitted
particulate, cause a major air pollution problem. This material
is of low specific gravity (1.5) and can be carried great distances
by moderate winds. Emission data are presented in Table 5.1-2.
-------
5-5
Table 5.1-1. Size of Particulate Matter Generated From Dust Conveyor System8
% By Weight
Particle Size (y) Before Cyclone After Cyclone
0-44 6.4 58
44 - 74 19.2 11
74 - 104 17.4 10
104+ 57 21
a) System serves soybeans, wheat, milo and yellow corn, and corn
cleaning. From Reference 7.
Table 5.1-2. Particulate Emissions From Grain Handling and Processing
Emission Source
1 . Terminal Elevators
Shipping or Receiving
Rail
Truck
Barge
(pounds/ton of grain
Ibs/ton
processed
1
1.4
1.2
Transferring, Conveying, etc. 2.0
Screening and Cleaning
Drying
5.0
5.5
processed)
range of emissions
(Ibs/ton)
(1 - 3)
(0.8 - 3.5)
(1 - 3.5)
(2 - 2.5)
(5 - 7)
(4-8)
2. Country Elevators
Shipping or Receiving
Rail 4 (3 - 8)
Truck 4.5 (2 - 8)
Barge 5.5 (3 - 8 )
Transferring, Conveying, etc. 3.5 (2 - 4)
Screening and Cleaning 8.5 (7 - 10)
Drying 7-5 (4 - 8)
-------
5-6
Emission Source Ibs/ton range of emissions
processed (Ibs/ton)
3. Grain Processing
Alfalfa Dehydrating (overall plant)3 4.5 20 - 70
Alfalfa Meal. Milling 0.2
Corn Meal (based on process weight loss) 5 1 - 27b
Soybean Processing (based on process weight 7 4 - 10b
loss)
Malted Barley Cleaner or Wheat Cleaner 0.2b
Milo Cleaner 0.35b
Barley Flour Milling 3b
4. Feed Manufacturing
Barley 3.2b
a) Not a true grain operation per se.
b) At cyclone exit (only non-ether soluble).
Reliability of Emission Factor
The factors for grain elevators are good due to a fair amount
of data and engineering evaluation of the available data.
Factors for grain processing and feed mills are questionable due
to lack of data.
Further work is indicated in the area of emission data from grain
processes and feed blending operations. The limited data in this
area are old and very incomplete. The factor ranking is shown in
Table 5.1-3.
Tabl-e 5.1-3. Emission Factor Ranking for Grain Handling and Processing
Emission Data Process Data Engineering Analysis3 Total
0-20 0-10 0-10
Elevators
10
Grain Processing
5
Feed Mills
4
7
6
7
9
8
8
26
19
19
a) Engineering Analysis performed by industry personnel.
-------
5-7
APPENDIX 5.1
Terminal Elevators
Country Elevators
Emission Source Emi
Shipping & Receiving
Rail
Truck
Barge
Transferring &
Conveying
Screening & Cleaning
Grain Drying
Grain Processing
Type
Alfalfa Dehydrating
Alfalfa Meal Milling
Barley Flour Milling
Corn Meal
Corn Meal
Soybean Processing
Wheat Cleaning
Malted Barley Cleaner
Milo Cleaner
Feed Manufacture
Type
Barley Feed
ssion Ibs/ton Ref.
Processed
1.0 3
1.1 4
2.0 3
.8 4
1.0 3
1.2 4
2.0 3
5 3
2-10 4
4 3
8 4
Ib/ton
20-70
0.2b
3.1b
26.7
1-10
4-10
0.2b
0.2a
0.35a
Ib/ton
3.2a
% Lost During Ref.
Processing
0.2 - 0.5% 4
0.2 - 0.5% 4
0.2 r 0.5% 4
0.1 - 0.25% 4
0.1 - 0.5% 4
0.1 - 0.5% 4
Ref. No.
5
6
6
2
4
4
6
1
1
Ref. No.
1
a) At cyclone exit
b) At cyclone exit
- but only includes non-ether soluble particulate,
-------
5-8
REFERENCES 5.1
1. Donnelly, W.H. Feed and Grain Mills, In: Air Pollution Engineering
Manual, Danielson, J.A. (ed.)- National Air Pollution Control
Administration, Raleigh, North Carolina, Public Health Service
Publication 999-AP-40. 1967. p. 359.
2. Contribution of Power Plants and Other Sources to Suspended Particulate
and S02 Concentrations in Metropolis, Illinois, U.S. Public Health
Service. National Air Pollution Control Administration. 1966.
3. Thimsen, D.J. and P.W. Aften. A Proposed Design for Grain Elevator
Dust Collector. J. Air Pollution Control Association. 18:738-742,
November 1968.
4- Personal Correspondence. Brain and Feed Dealers National Association,
Washington, D.C., September 1969. Dr. H. L. Kiser.
5. Anon. Air Pollution from Alfalfa Dehydrating Mills. Air Pollution
Engineering Program, U.S. Public Health Service, Robert A. Taft
Sanitary Engineering Center, Report, A60-4, 1960.
6. Larson, G.P.,, G.I. Fisher and W.J. Hamming. Evaluating Sources
of Air Pollution. Industrial and Engineering Chem. 45:1071,
May 19;53.
7. Private Communcation. G. Sallee. Midwest Research Institute, Dec. 17,1969.
GENERAL REFERENCES
McLouth, M.E. and H.J. Paulus. Air Pollution from the Grain Industry.
J. Air Pollution Control Association. ]_1_:313-317, July 1961.
Cote, W.A. Grain and Dust Emissions in Our Atmosphere. U.S. Public
Health Service, National Air Pollution Control Administration,
Proceedings of the National Symposium on Air Pollution of the Grain
and Feed Dea-lers National Association, January 1967, Washington, D.G.
Interstate Air Pollution Study, St. Louis, Phase II Project Report f2;
Air Pollution Emission Inventory, U.S. Public Health Service, 1966v
Stern, A,C. (ed.). Air Pollution Vol. Ill, 2nd Edition, New York,,
Academic Press, 1968. p. 276-280.
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5-9
5.2 MEAT SMOKEHOUSES
Process Description
Meat smoking has been employed for centuries for the
preservation of meat and fish products. Today, however, with the
influx of more efficient and more economical methods of curing and
preserving meat, smoking is primarily used to impart flavor and
color to the meat for better "customer appeal". While some smoking
of fish and poultry products is done, the vast majority of smoked
products are meats of bovine and porcine origin. In addition, a
token amount of vegetable products are smoked as gourmet items.
Smoking is a diffusion process in which food products are
exposed to an atmosphere of hardwood smoke. This exposure causes
various organic compounds to be absorbed by the food. Smoke is
produced commercially in the United States by three major methods:
1) burning dampened sawdust (20-40% moisture); 2) burning dry (5-9%
moisture) sawdust continuously, and 3) by friction. Today, burning
dampened sawdust and kiln-dried sawdust are the most widely used
methods. Smoke production by frictiontxy pressing the end grain
of hardwood block against a rotating carbide-tipped diskis in
use to some extent with relatively small production units.
n
The smoke production takes place at temperatures from 700 - 1000°F.
Most large, modern, production meat smokehouses are the recirculating
type, in which smoke is circulated at reasonably high temperatures
throughout the smokehouse. There are some atmospheric smokehouses
still in operation, but these outmoded systems are rapidly giving
way to the modern recirculating type. Recirculation smokehouses
usually include automatic temperature and humidity controls, and
thus the opacity and make up of exhaust gases are more constant
than those from atmospheric units.
-------
5-10
The actual smoking of the meat is an absorption or scrubbing
p
process, rather than a settling process, and it has been found that
the rate of deposition of phenols from the smoke is about 20 times
o
as high for wet surfaces as for dry surfaces. Furthermore, the
percentage loss of the smoke particles is a linear function of
2
temperature,
Liquid smoke materials prepared by burning hardwood or hardwood
sawdust in a manner similar to that used in meat smoking are
available. There are many potential advantages to liquid smoking;
however, the fear that this process might deposit lethal quantities
of toxic materials from the smoke onto the meat has restricted its
development and use in many states. From an air pollution standpoint!
liquid smoking is ideal, since the scrubbing process which produces
the liquid smoke simultaneously removes the air pollutants.
Another rather new smoking method is electrical precipitation,
in which the smoke particles are electrically charged and
precipitated on the meat. This process, though not widely used,
has the advantages of faster smoking and greater use of generated
smoke. Air pollutants from the process are considerably less than
those from conventional methods. Spacing problems and difficulty
with irregularly shaped smoked products have severely curtailed the
development of the electrical smoke precipitator as a major smoking
process..
Both T;ow voltage electrostatic preci pita tors and direct-fired
afterburners may be used to reduce particulate and organic emissions..
Aldehydes may be decreased by 35-40% and particulates by about 65%
with either device.
-------
5-11
Factors Affecting Emissions
The composition of smoke is dependent on several factors,
including 1) type of wood, 2) type of smoke-generator, 3) moisture
content of the wood, 4) temperature of combustion, 5) air supply,
6) rate and quantity of smoke deposition, and 7) amount of smoke
recirculated.
Emissions
While the smoking process is widely used in meat packing plants,
very little work has been done to estimate the smoking industry's
contribution to air pollution. There have been some studies made
on the chemical composition of smoke from smokehouses, and this
information coupled with production data was used to determine the
emission factors in Table 5.2-1.
Table 5.2-1. Emissions From Meat Smoking, Ibs/ton of Meat3
Pollutant
Parti cul ate
CO
HCC
Aldehydes
Organic Acids6
a) Based on 110 Ibs
b) Controls consist
Uncontrolled
Range Avergae
0.04 to 0.5 0.27
0.4 to 0.7 0.6
0.03 to 0.16 0.07
0.065 to 1.1 0.08
0.23 to 0.25 0.24
of meat smoked per pound of
of a wet collector and low
Controlled
Average
0.09
Neg.f
Neg.f
-0.05
0.13
wood burned.
voltage precipitator
V
\
in
series, or direct-fired afterburner.
c) As methane.
d) As formaldehyde.
e) As acetic acid.
f) With afterburner.
-------
5-12
Reliability of Emission Factors
Concentrations of particulate emissions and some gaseous emissions
have be,en reported in the literature. However, little data exists
which relates the volume of exit gases to the amount of wood burned,
or to the amount of food smoked. The overall emission factor must
therefore be considered questionable as shown by the ranking in
Table 5.2-2.
Table 5.2-2. Emission Factor Ranking
Emission Data Process Data Engineering Analysis Total
0-20 0-10 0-10
8 2 2 12
-------
5-13
APPENDIX 5.2
Emission Data
1. Grain loading range and average particulate emissions
from smokehouses^
a. range: 0.016 to 0.234 gr/scf
b. average: 0.1.16 gr/scf - 86%
2. Production figures - meat smoking process.
a. 20 Ibs. sawdtfst"burned per hour
b. 2200 Ibs. meat smoked per hour
c. 300 cfm exhaust gases
3. Particulate emission.
300 cfm x 0.116 gr/scf x 60 min/hr x j^
x 1 hr/2200 Ibs x 2000 Ibs/ton =
0.272 Ibs particulates/ton of meat
or 29.8 Ibs particulates/ton of sawdust ~.^. f"
.iff '.' ,>
"Ti Carbon monoxide and hydrocarbons. , '" '"".
These pollutants were estimated from similar processes, ;Vi
v--'
namely charcoal and open wood burning.
Since 29.8 Ibs particulates/ton of sawdust is within
the range of particulate emissions for charcoal
manufacturing and open wood burning (see Table 5.2-3),
the CO and HC emission factors for smokehouses ^
were assumed to fall within these respective randies .«p;
by about the same ratio. Thus the CO emission^actor ^.,
is about 55 Ibs/ton of sawdust or about 0.55 Ibs/ton If'
of meat. Similarly, HC emissions should be about 7 Ibs/ton
of sawdust or about 0.07 Ibs/ton of meat.
4
Table 5.2-3. Wood Smoke Emissions
Charcoal Pollutant. Ibs/ton of Wood Open Burning of Wood
80 CO 50
25 HC 3
100 Particulates 17
-------
5-14
5. Aldehydes and organic acids.
a. Aldehydes (as formaldehyde)
Molecular weight = 30
Average concentration = 57 ppm - 30%
57 x 10"6 x 300 cfm x 60 min/hr = 1.025 cf/hr.
1.025 cf/hr x 2000 Ibs/ton x 1 hr/2200 Ibs x
30 Ibs/lb mol = 0.0725 Ibs/ton meat
387 ft3/lb mol
b. Organic acids (as acetic acid)
Molecular weight = 60
Average concentration = 89 ppm - 2%
89 x 10"6 x 300 cfm x 60 min/hr = 1.60 cf/hr
1.60 cf/hr x 2000 Ibs/ton x 1 hr/2200 Ibs x
60_ = 0.225 Ibs organic acids/ton of meat
387
Average control efficiencies of 65% for particulates, 37% for
aldehydes, and 55% for organic acids for either a scrubber-precipitator
combination or an afterburner, were used.
-------
5-15
REFERENCES 5.2
1. Polglase, W.L., H.F. Dey, and R.T. Walsh. Food Processing /
Equipment in: Air Pollution Engineering Manual, Danielson
J.A. (ed.). National Air Pollution Control Administration,
Raleigh, North Carolina. Public Health Service Publication
999-AP-40, 1967. p. 750-755.
2. Draudt, H.N. The Meat Smoking Process: A Review. Food
Technology. 17_: 85-89, December 1963.
3. Foster, W.W. and T.H. Simpson. Studies on the Smoking Process
For Food. 0. Sci. Food Agr. Ij2:363, December 1961.
4. Supra, Section 3.4 and 4.4.
5. Private Communication. Maryland State Department of Health.
November 21, 1969.
GENERAL REFERENCES
Jensen, L.B. Microbiology of Meats, 2nd Edition. Champaign, 111.
Garrard Press, 1945. .
Soderholm, N. and D.E. Bonn. Air Pollution Control of Smokehouse
Emission in the Packing Industry. J. Air Pollution Control
Association. _7(l):36-28, May 1957.
Goos, A.W. The Thermal Decomposition of Wood. In: Wood Chemistry
2nd Edition Volume 2. Wise, I.E. and E.C. Jahn (eds.) New York,
Reinhold Publishing Company. 1952. p. 846-850.
Simon, S., A.A. Pypinski, and F.W. Taube. Water-Filled Cellulose
Casings as Model Aborbents for Wood Smoke. Food Technology.
p. 114-118, November 1966.
-------
5-16
5.3 FERMENTATION
General
A wide spectrum of product materials are derived from
various fermentation processes. All fermentation industries
employ one common element, the biochemical action of micro-
organisms to convert one substance to another. Fermentation
industries can be divided into three subgroups according to their
manufactured products. Table 5.3-1 lists the predominant
fermentation products:
Table 5.3-1. Fermentation Products
Food Pharmaceuticals Chemical
Beer Antibiotics Organic Acids
Wine Hormones
Whiskey Enzymes
Vitamins
Penicillin
The U. S. production of beers, liquors, and wines (116.5,
,7.3, and 5.0 million barrels, respectively in 1967) completely
dwarfs the production of the other fermentation products and
emissions from the production of these beverages also dwarfs the
emissions from the remaining fermentation processes. For this
reason, only emissions from the production of beers, liquors, and
wines will be considered in this report.
Process Descriptions
Beer and allied products are beverages of low alcoholic
content (2 to 7%) made by brewing various cereals with hops, usually
-------
5-17
VENT
LAUTER
MAI TING - UIACLJ TI IP TIIR _».- HDP6? RRFW
FILTER
SPENT
GRAINS
. VENT
TO CARBONATION
CARBONATION COLD
^^ AMD E-e-pnc-MT/->e> - FIITFP - NA/flPT
*" AINU < ' r triMC-lM 1 Urt rll_IC.n WUtt 1
FILTRATION TANK
HOP
. *. JACK
FILTER
-*1
i
SPENT
HOPS
HOT
^ *A»/^OT
TANK
I
SPENT
YEAST
COLD CARBONATION
.^. <rnRACF ANH . . -» ROTTI IMP. «. .*
FILTRATION
"PA«?TFI IRI7AT
i MO 1 L.Umt.MI
ION
Figure No. 5.3-1 Beer manufacturing flow diagram
-------
Cooling
coil
Slop
Screen
-------
5-19
added to impart a more or less bitter taste and to control the
fermentation that follows. The cereals employed are..ma.l feed
barley and malt adjuncts: flaked rice, oats, and corn. Brewing
sugars, syrups, and yeast complete the raw materials. A flow
diagram of the brewery operations describes the beer making
process as shown in Figure 5.3--1. The four main brewing
production stages and their respective sub-stages are:
[1] BREWHOUSE OPERATIONS, which includes a) malting of the
barley; b) addition of adjuncts (corn, grits, and rice) to
barley mash; c) conversion of starch in barley and adjuncts to
maltose sugar by enzymatic processes; d) separation of wort from
grain by straining; and e) hopping and boiling of the wort.
[2] FERMENTATION, which includes a) cooling of the wort; b) additional
yeast cultures; c) fermentation for 7-10 days; d) removal of
settled yeast; and e) filtration and carbonation. [3] AGING,
which lasts from 1-2 months under refrigeration . [4] PACKAGING
PROCESS, which includes a) bottling-pasteurization, and b) racking-
draft beer.
The spent hops, spent grains, and spent yeast (see
Figure 5.3-1), which have been separated from the liquid which
ultimately is beer, are generally drained and then dried. The
dried spent products are then either sold as by-products or
wasted.
Parti cu'i ate control systems or grain handling systems are
generally the only type of air pollution controls used. These
systems consist of cyclones.
Various fermented products, upon distillation and aging,
yield the distilled liquors. Figure 5.3-2 shows the flow chart
for whiskey. There are a multitude of distilled liquors,
differing in raw materials and distillation processes. By law,
the aging of bourbon or rye whiskey of claimed age must take
place in charred new white-oak barrels of approximately 50 gallons.
These are kept in bonded warehouses at 65° to 85°F and at a
-------
5-20
preferred humidity of 65 to 70 percent for 1 to 5 years.
During this time, an evaporation of the contents takes place,
largely through the ends of the barrel staves. By reason of
a more rapid capillary travel and osmosis of the smaller water
molecules in comparison to alcohol molecules, an increase in
the percentage of alcohol is found in the barrel contents. The
government shrinkage allowance is approximately 8 percent in the
first year, 4 percent in the second year, 4 percent in the third,
and 3 percent in the fourth year. The distillate from the spirit
is still under 160 proof and is subsequently diluted upon
barreling to about 100 proof. Packaging of the finished liquor is
the last manufacturing process in the production of distilled
spirits.
As shown in Figure 5.3-2, the discharge liquor, known as
slop or spillage is treated to separate the solids from the
liquid slop. After vacuum evaporation of the liquid portion, it
is added to the solids and the mixture dried in rotating steam-
heated driers to produce cattle feed. Particulates and odors
are emitted from this drying process.
Wines are classified as natural (alcohol 7 to 14%), fortified
(alcohol 14 to 30%) sweet or dry, still as spark-ling. The
fortified wines have alcohol or brandy added. In the sweet
wines, some of the sugar remains.
The manufacturing processes for most wines are generally the
same. For example in the manufacture of dry red wine, red or
black grapes are run through a crusher which macerates them
but does not crush the seeds, and also removes part of the
stems. The resulting pulp, or "must", is pumped into 3,000-10,000
gallon tanks, where sulfurous acid is added to check the growth
of wild yeast. An active culture of selected and cultivated yeast
equal to 3-5 percent of the volume Is then added. During
fermentation, the temperature rises, so that cooling coils are
-------
5-21
necessary to maintain a temperature of 85°F. When the fermentation
process slows, the juice is pumped out of the bottom of the vat
and back over the top. The wine is run into closed tanks in
the storage cellar where, during a period of 2 to 3 weeks, the
yeast ferments the remainder of the sugar. By quick aging methods,
it is possible to put out a good sweet wine in 4 months. These
methods include pasteurization, refrigeration, sunlight, ultra-
violet light, ozone, agitation, and aeration. The wine is finally
racked, clarified, and bottled.
Factors Affecting Emissions
The general factors affecting atmospheric emissions in
addition to type and throughput of the process are general plant
operation and maintenance, and degree of control on solids (grain)
handling systems. Gaseous control systems are rarely used on
fermentation processes; however, particulate controls in the
form of cyclones are commonly used on the grain handling systems.
Emissions
Emissions from fermentation processes are nearly all gases
and primarily consist of carbon dioxide, hydrogen, oxygen, and
water vapor, none of which presents an air pollution problem.
Purification and concentration of the fermentation product and
by-products are generally carried out by distillation, drying, and
filtration, and it is in this area that gaseous emissions occur.
These emissions are mainly hydrocarbons and are emitted from the
condensers, dryer vents, and mash cooker vents.
Origin of emissions from the individual processes involved
in beer, liquor, and wine production are: [1] BEER a) grain
handling - particulates; b) drying of spent grains, hops, and
-------
5-22-
yeast-- gaseous hydrocarbons; c) vent gases from brew kettle -
primarily Hg, C02> 02> and H20 vapor. [2] DISTILLED LIQUORS
a) grain handling; b) drying spent grains and yeast - gaseous
hydrocarbons; and c) whiskey aging warehouse - gaseous hydrocarbons,
[3] WINE -no significant emissions. .;.-/ . ... ,,.,.,.
Neither emission data nor sufficient process data are available
from which emissions can be calculated.
\
-------
5-23
REFERENCES 5.3
1. Fermentation. Kirk-Othmer Encyclopedia of Chemical Technology.
New York, Interscience Publishers, 1965. p. 871.
2. Beer and Brewing. Kirk-Othmer Encyclopedia of Chemical
Technology. New York, Interscience Publishers, 1964. p. 314.
3. Shreve, R.N. (ed.). Chemical Process Industries, 3d Ed.
New York, McGraw-Hill Book Company. 1967. p. 591-608.
4. Boruff, C.S. Recovery of Fermentation Residues as Feeds.
Industrial and Engineering Chemistry. 39(11): 602-607,
May 1947.
-------
6. METALLURGICAL INDUSTRIES
The metallurgical industries can be broadly divided into
primary and secondary "metal, production operati'ons. The primary
metal industries produce metal from ore. The secondary metal industries
recover metal from scrap and salvaged metal.
The secondary metallurgical industries, discussed, in this .
section, are steel foundries, lead smelting, magnesium smelting
and zinc processing. The major air contaminants from these .
operations are particulates in the forms of metallic fumes,
smoke and dust. The small particle sizes of the emissions
require high efficiency collectors such as electrostatic
precipitators, baghouses and high energy scrubbers (e.g. , venturi
scrubbers). .
The metallurgical processes, except the coking process,
discussed in this section are limited to processes which utilize
metal scrap and salvaged metal to produce a metal or metal alloy.
Coking, while not a metallurgical process, is an essential
step to the production of a fuel and reducing agent required by
many metallurgical processes. Coke is used in blast furnaces
and smelters to generate the heat and reducing atmosphere vital
to the production of iron, lead, zinc, copper, and other metals
from their ores.
In general, emission data for these processes are sparse.
Some of the data cited are for processes of a similar type rather
than for the listed process itself.
Typical Particle Size Distribution,
Weight Percents Metallurgical Industries
Coking Process 0-5y 5-10P 10-20y 7-20
Steel Foundries
Electic Arc
Oxygen Lanced Open Hearth
Secondary Lead Smelting
Secondary Magnesium Smelting
Secondary Zinc Processing
to
68
46
95
100
5
7
22
4
No
5
10
17
.8 0.2
Information
90
15
15
-
"
a) Magnesium fume is quite fine; the fume is probably all less than
5 microns in diameter.
-------
6-2
6.1 METALLURGICAL COKE MANUFACTURE
Process Description
Coking is the process of heating coal in an atmosphere of low
oxygen content, i.e., destructive distillation. During this process
organic compounds in the coal break down to yield gases and a residue
of relatively non-volatile nature. Two processes are used for the
manufacture of metallurgical coke, the beehive process and the by-
product process. The by-product process, however, accounts for
about 98% of coke produced.
The beehive oven is a refractory lined enclosure with a dome-
shaped roof. The coal charge is deposited onto the floor of the
beehive and leveled to give a uniform depth of material. Openings
to the beehvve oven are then restricted to control the amount of
air reaching the coal. The carbonization process begins in the
coal at the top of the pile and works down through the pile. Th.e
volatile matter be-ing distilled escapes to the atmosphere through
a hole in the roof. Although some attempts have been made at
capturing the gases from beehive ovens for waste heat recovery
or by-product recovery, most have been unsatisfactory. At the
completion of the coking time, the coke is "watered out" or quenched.
The by-product process, as the name suggests, is oriented
toward the recovery of the gases produced during the coking cycle.
The coking chamber is a rectangular oven 6 to 14 feet high, 30 to
43 feet in length, and 12 to 22 inches in width. These ovens are
grouped together in a series called a coke battery. Coal is charged
to the oven through ports in the top and then sealed. Heat is
supplied to the ovens by burning some of the coke gas produced.
Upon completion of the coking period, the coke is pushed from the
oven by a ram and quenched with water. Coking is largely accomplished
at temperatures of 1650°F to 2150°F for a period of 16 to 20 hours.
-------
6-3
Visible smoke, hydrocarbons, CO, and other emissions originate
from the following by-product coking operations: (1) charging of
coal into the red-hot ovens, (2) oven leakage during the coking or
carbonization period, (3) pushing the coke out of the ovens, and
(4) quenching the hot coke.
Associated with both coking processes are the material handling
operations. These include: unloading coal, storage of coal, grinding
and sizing of coal, screening and crushing coke, and coke storage and
loading. All of these material handling operations are potential
particulate emission sources. In addition, the operations of oven-
charging, coke pushing, and quenching produce particulate emissions.
For the most part, the latter three operations go uncontrolled at the
present time.
Virtually no attempts are being made to prevent gaseous emissions
from beehive ovens. Gaseous emissions from.the by-product ovens are
drawn off to a collecting main and are subjected to various operations
for separating ammonia, coke oven gas, tar,phenol, light oil (benzene,
toluene, and xylene), and pyridine. These unit operations are poten-
tial sources of hydrocarbon emissions.
Oven charging operations and leakage around poorly sealed coke
oven doors and lids are major sources of gaseous emissions from by-
product ovens. Sulfur is present in the coke oven gas in the form
of hydrogen sulfide and carbon disulfide. Some plants desulfurize
the coke oven gas before consuming it. If the gas is not desulfurized,
the combustion process will produce sulfur dioxide which is, in
turn, emitted to the atmosphere.
-------
6-4
Factors Affecting Emissions
Factors affecting emissions include the amount of fines in
the coal used and the degree of dust control practiced on the
material handling phases. The manner and speed of charging the
oven affects the particulate and the gaseous emissions from the
oven. Routine maintenance practices on the coke oven doors affect
the amount of leakage around the doors. Most coking coals are
low sulfur coals; however, a variation in the sulfur content of
the coal will vary the amount of sulfur-bearing compounds in the
emissions.
Upsets in coking operations can cause significant amounts of
gaseous pollutants to be discharged. If suction is lost on the
collecting mains of a by-product battery, hydrocarbons, arnmoniaj
carbon monoxide, and sulfur-bearing compounds will be released
to the atmosphere.
The water used for coke quenching can affect the emissions
from the quenching process. In some plants contaminated waste
water, cbntainina phenol and clorides from other portions of
the coking operations, is used as quench water. Since quenching
causes sudden, violent evaporation, liquid mist as well as coke
particles are entrained in the rising vapor. A substantial
portion of this material does, however, fall out in the immediate
area of the quenching water.
Emissions
Data concerning emissions from the coking process are sparse.
Most of the data are limited to the composition and concentration
of the by-product oases and particulates. Table 6.1-1 contains a
list of by-product substances which are normally recovered durino
by-product coking operations, but would be emitted in the case of
beehive coking.
-------
6-5
Table 6.1-1. Recovered Coking By-Products
Quantity Recovered
Material (Ibs/ton of coal charged)
Coke Gas 105
Tar Mist , 104
Light Oil 8
Ammonia , 1.6
Hydrogen Sulfide 1.7
Some data on coking emissions were published recently in a
United Nations report. These data were obtained from European
operations, and no judgments on their comparability to United
States operations or their accuracy have been made. Table 6.1-2
lists emission factors based on European data.
Reliability of Emission Factors
Limited data are available for both gaseous and particulate
emissions from coking operations. Much of the reported data was
based on European measurements and estimates which frequently com-
bined measured concentrations with estimated total gas flows to
obtain total emissions. Table 6.1-3 presents the factor ranking.
Further emission research is indicated in this area.
Table 6.1-3. Emission Factor Ranking for Metallurgical Coke
Emission Data Process Data Engineering Analysis Total
0-20 0-10 0-10
Particulate 7 6 3 16
Gases 4 .6 3 13
-------
Table 6.1-2. Emission Factors for By-product Co
Operation Participate
Unloading 0.4 (0.07-0.96)
Charging 1.5 (0.11-4.3)
Coking Cycle 0.1
Discharging 0.6 (0.14-1.37)
Quenching 0.9 (0.5-1.40)
TOTALS 3.5
CO
0.6 (0.08-1.2)
0.6
0.07 (0.01-0.13)
1.27
CH4
1.9 (0.23-3.5)
1.5
0.2 (0.04-0.40)
3.6
king, Ibs/ton of Coal Charged
CXHX
0.6
0.6
Tar
1.3 (0.23-2.0)
0.8
0.06 (0.01-0.10)
2.16
H2S
0.03
0.1
0.08b
0.21
I
NOX
0.03
0.01
NH-,
0.02
0.06
0.12b
0.20
S02
0.02
0.002
0.022
a) Aromatic Hydrocarbons, e. g., benzene (CeHs) - reported as methane.
b) Emission reported from discharging and quenching combined.
-------
6-7
APPENDIX 6.1
Table 6.1-4. Coke Plant Emission Data
Emissions, Ib/ton of coal charged
Parti cul ate CO CH4 CXHX Tar
Plant 1 2
Unloading 0.96
Charging 4.30 1.2 3.5 0.6 as Qty 1.7-2
Discharging 0.14-1.37 0.01-0.13 0.04-0.4
Quenching 0.55-1.40
(Ib/ton coke)
Plant 2 2
Unloading 0.07-0.11
Charging 0.11-0.15
Discharging 0.29-0.44
(Ib/ton coke)
Other data4
Quenching 0.5
a) Aromatic hydrocarbons> e.g., benzene
-------
6-8
Table 6.1-5. Polish Estimates of Coke Plant Emissions 3
Pollutant
Coal Dust
Tar
Methane & homologues
Ethyl ene & homologues
Acetylene
Carbon Monoxide
Benzene
Napthalene
Phenol
Pyridine
Ammonia
Hydrogen Sulfide
Hydrocyanic acid
Oxides of Nitrogen
Sulfur Dioxide
Carbon Disulfide
Chlorine
Chlorides
Cnl-Fa+oc
Formula
CnH2n+2
CnH2n
C2H2
CO
C6H6
C10H8
CeHsOH
C5H5N
NH3
H2S
HCN
NOX
S02
CS2
C12
ci-
Qn*
Charging*
1.366
0.229
0.227
0.033
0.002
0.081
0.033
0.011
0.013
0.134
0.018
0.026
0.002
0.029
0.024
0.002
Coking Cycle*
0.130
0.768
1.487
0.224
0.013
0.554
0.019
0.075
0.022
0.013
0.059
0.103
0.007
0.013
0.002
0.002
0.007
Discharging*
& Quenching
0.400
0.022
-- .
0.011
0.031
0.174
0.125
0.084
0.011
0.062
n ie;a
*lbs/ton charged
-------
6-9
REFERENCES 6.1
1. Unpublished data. Maryland State Department of Health.
2. Air Pollution by Coking Plants. United Nations Report -
Economic Commission for Europe. ST/ECE/Coal/26. 1968.
pp.3-27.
3. Ibid, p. 19.
4. Fullerton, R. W. Impingement Baffles to Reduce Emissions
From Coke Quenching. J. Air Pollution Control Association.
17:807-809, December 1967.
GENERAL REFERENCES
Griswold, 0. Fuels, Combustion and Furnace. New York. McGraw
Hill Book Company, Inc. 1946.
Smith, Gordon L., Jr. Air Pollution Control of Beehive Coke Ovens.
Master's Problem Report. West Virginia University. Morgantown,
West Virginia. 1968.
McGannon, Harold E. The Making, Shaping, and Treating of Steel.
Pittsburgh. United States Steel Corporation. 8th Edition. 1964.
-------
6-10
6.2 STEEL FOUNDRIES
Process Description
Steel foundries produce steel castings by melting steel metal
and pouring it into molds. Castings of nearly any desired shape
or size can be made in this manner.
The melting of steel for castings is accomplished in one of
five types of furnaces. These various types are direct electric
arc, electric induction, open hearth, crucible, and pneumatic
converter. The first three types are most frequently used since
the older crucible and pneumatic types are being replaced by
electric furnaces. Raw materials supplied to the various melting
furnaces include: steel scrap of all types, pig iron, ferroalloys
and limestone. The basic melting process operations are furnace
charging, melting, tapping the furnace into a ladle and pouring the
steel into molds.
The direct electric arc furnace is a refractory-lined, cylin-
drical basin. The roof is a flat dome with openings for the electrodes.
The furnace is charged either through a door in the side of the,
furnace or through the top of the furnace after the roof is swung
aside. Heat for the melting process is supplied by applying low
voltage, high current electrical power to carbon or graphite electrodes
positioned just above the level of the metal or bath. Arcs are
formed between the electrodes and the bath, and current travels
through the bath. Thus, heat is supplied to the bath by radiation
from the arcs and by the electrical resistance of the bath to
the current. Steel is tapped from the furnace after the electrodes
are raised by tilting the furnace and allowing the metal to run
out the tap hole into a ladle. Capacities of direct electric arc
furnaces range from 3 to 200 tons per heat. Heat times vary from
one to four hours. Oxygen lancing may be used.
-------
6-11
Fume control is achieved by placing a canopy hood above the
furnace or by having an exhaust takeoff in the furnace roof or
sidewall. While the overhead canopy hood could, possibly, catch
particulate emitted from the charge or tap operations, the roof
hood and sidewall tap do not have this potential.
Open hearth furnaces range in size from 10 to 600 tons capa-
city. Most open hearths in the United States are basic furnaces,
i.e., utilize basic refractory brick and a basic process. The
furnaces have a long, relatively shallow hearth and a low roof.
Heat for steel melting is supplied by combustion of natural gas,
coke oven gas, heavy fuel oil or tar. These heat sources may
be augmented by oxygen enrichment of combustion air or oxygen
lancing. Combustion air is preheated in a regenerative chamber
system consisting of brick checker-work heated by the exhaust
gases. Raw materials are charged to the furnace through doors
in the front of the furnace. The furnace is tapped through a .
hole in the rear of the furnace. Oxygen lancing is frequently
used.
Fume control may be achieved by processing the waste gases
downstream of the regenerative chambers. Gas temperatures may
require the use of a waste heat boiler or other cooling apparatus
upstream of the air pollution control equipment.
Electric induction furnaces are generally small in capacity,
usually 1/4 to 1 ton in size. These furnaces are generally used
for melting with little or no refining of the charged materials.
The charge is introduced into the top of the furnace. Energy
is supplied to the furnace by activating the induction coil around
the furnace. The electrical resistance to secondary currents in the
charged material generates heat which, in turn, melts the charged
material. The completed heat is tapped either directly into molds
or into a ladle in the case of larger furnaces.
-------
6-12
Fume emissions from the electric induction process can be
captured by use of a canopy hood. This type of hood can potentially
control emissions generated during charging and tapping.
An integral part of the steel foundry operation is the prepara-
tion of casting molds and the shakeout and cleaning of these castings.
Molds can be made from many materials. The choice of molding material
is dependent upon variables such as size of castings, metal temperature,
and the pouring method. Some common materials used in molds and
cores for hollow casting include sand, oil, clay, and resin.
Shakeout is the operation in which the cool casting is separated from
the mold. The castings are commonly cleaned by shotblasting, and
surface defects such as fins may be removed by burning and grinding.
Factors Affecting^ Emissions
Factors affecting emissions from the melting process include
quality and cleanliness of the scrap and increased oxygen lancing.
Additional particulate is generated due to the oxidation of iron,
zinc, lead and other metals which depend upon the source of scrap
metal in the furnace charge. If the scrap metal is quite dirty or
oily or increased oxygen lancing is employed, the emission factor
should be chosen from the high side of the factor range. The
concentrations of oxides of nitrogen will be dependent upon operating
conditions in the melting unit such as temperature and the rate
of cooling of the exhaust gases. The concentration of carbon
monoxide in the exhaust gases is dependent on the amount of draft
on the melting furnace. Sulfur oxide emissions depend mainly on
the sulfur content of the fuel when used. Emissions from the . ^
shakeout and cleaning operations, being mostly particulate, will
vary according to the type and efficiency of dust collection and
air cleaning systems used.
-------
6-13
Gaseous emissions from the mold and baking operations are
dependent upon the fuel used by the ovens and the temperature
reached in these ovens. Odorous emissions may be produced by
baking operations, depending on the resins, oils and other mold
ingredients used by the foundries.
'.
Emissions
Particulate emissions from steel foundry operations include'
iron oxide fume, sand fines, graphite and metal dust. These partic-
ulates range in size from 0.1 microns to 1000 microns or larger.
The smaller particles are the oxide fumes from melting operations,
and the larger are typical of grinding operations
Table 6.2-1. Typical Particle Size Distribution
for Melting Operations in Weight Percent
Electric Arc Furnace ;
Oxygen Lanced Open Hearth2
10-20U >20U
10 15
17 15
Table 6.2-2 . Foundry.Operations Emissions
Operation
Shakeout
Sand Cooler
Airless Abrasive Cleaning
Grinders
Dry Sand Reclaimer
Screens and Transfer Points
Grain Loading (grains/SCF)
0.5 - 1.0
1.0 - 20.0
0.5 - 5.0
0.5 - 2.0
10.0 - 40.0
0.5 - 3.0
-------
6-14
Gaseous emissions from foundry operations include oxides of
nitrogen, oxides of sulfur, and hydrocarbons.
6.2-3. Emission Factors for Steel Foundries
Uncontrolled Emissions - Ib/ton processed
Type of Process Parti cul ate Range
NOv Range
Electric Arc Furnacea
Open Hearth
Oxygen Lanced Open Hearth0
Induction Electric
13
11
10
0.1
3.5-40
1.5-20
9.3-10
0,2 0.07-0,4
0.013
a) Electrostatic precipitator
Baghouse (Fabric filter)
Venturi scrubber and other
high energy scrubbers
b) Electrostatic precipitator
Baghouse
Venturi scrubber and other
high energy scrubbers
c) Electrostatic precipitator
Baghouse .
Venturi scrubber and other
hitjh energy scrubbers
d) Usually not controlled
92-98% control .efficiency
98-9955 control efficiency
94-98% control efficiency
95-98.5% control efficiency
99.9% control efficiency
96-99% control efficiency
95-98% control efficiency
99% control efficiency
95-98% control efficiency
-------
6-15
Reliability of Emission Factors
Particulate emission data are generally available for the
various steel melting operations, and these emission factors are
considered to be reliable. Gaseous emission data is not available,
and the factors cited are questionable. Additional experimental
work is recommended to determine NOx, CO, and hydrocarbon emission
from the various steel melting and casting processes.
Table 6.2-4 presents the factor rankings.
Table 6.2-4. Steel Foundry Emission Factor Ranking
Emission Data Process Data Engineering Analysis Total
0-20 0-10 0-10
Particulate 16 9 5 30
Gases 24 28
-------
6-16
APPENDIX 6.2
Electric Arc Furnace - Participate Emissions Data
Factor, Ibs/ton
10.0
3.5-4.0
40.0
12.7
30.0
10.7
6.8
12.0
9.3
18.6
7.6
10.4
5.5
5.2
13.4
4.5
5.8
15.3
12.8
6.1
37.8
29.4
7.0
4.5
10.6
Reference
5
5
5
5
5
5
6
6
7,8
7,8
9
9
9
9
9
10
10
10
10
11
12
12,13
14
19
19
335.9 ,. .
Average = -r: =12.9
-------
6-17
Open Hearth Data (no oxygen lances)
* Factor, Ibs/ton Reference
17.50 15
12.90 15
7.95 . Ifi
5-10.00 17
1.50 19
7.50 19
20.00 19
Average = -'7 > = 10.7
Open Hearth Data (oxygen lanced)
Factor, Ibs/ton Reference
10.2 18
9.3 10
Although emission rates for oxygen lanced open hearths are.
generally believed to be higher than those for non-lanced furnaces,
the emission factors determined for this report do not indicate that
such is the case. No explanation for this discrepancy is evident.
-------
6-18
REFERENCES 6.2
1. Erickson, E. 0. Dust Control of Electric Foundries in
Los Angeles Area. Electric Furnace Steel, Proceedings
(American Institute of Mining and Metallurgical Engineers)
Jl: 156-60. 1953.
2. Bishop, C. A., et al. Successful Cleaning of Open Hearth
Exhaust Gas with a High-Energy Venturi Scrubber. 0. Air
Pollution Control Association. Vh83-87. February 1961.
3. Varga, 0., and H. W. Townie. A System Analysis Study of
the Integrated Iron and Steel Industry. Battelle Memorial
Institute. Columbus, Ohio. 1969.
4. Schueneman, J. J., M. D. High and W. E. Bye. Air Pollution
Aspects of the Iron and Steel Industry. Public Health Service
Bulletin 999-AP-l. 1963. p. 57.
5. Foundry Air Pollution Control. Committee. Foundry Air Pollution
Control Manual. 2nd Edition. 1967. Des Plaines, Illinois.
p. 8.
6. Foundry Air Pollution Control Committee. Foundry Air Pollution
Control Manual. 2nd Edition. 1967. Des Plaines, Illinois.
p. 8.
7. Coulter, R. S. Bethlehem Pacific Coast Steel Corporation.
Personal Communication. April 24, 1956 as cited in Air
Pollution Aspects of the Iron and Steel Industry.' U. S.
Public Health Service Publication 999-AP-l. Reference 74.
p. 59.
8. Coulter, R. S. Smoke, Dust, Fumes Closely Controlled in
Electric Furnaces. Iron Age. J_73_: 107-10. January 14, 1954
-------
6-19
9. Los Angeles"Cdunty Air Pollution Control District. Unpublished
Data as cited in Air Pollution Aspects of the Iron and Steel
Industry. U. S. Public Health Service Publication 999-AP-l.
Reference 76. p. 109.
10. Kane, J. M. and R. V. Sloan. Fume Control - Electric Melting
Furnaces. American Foundryman. Tj3:33-35. November 1950.
11. Pier, H. M. and H. S. Baumgardner. Research-Cottrell, Inc.
Personal Communication as cited in Air Pollution Aspects of
the Iron and Steel Industry. U. S. Public Health Service
Publication 999-AP-l. Reference 78. p. 109.
12. Faist, C. A. Remarks, Electric Furnace Steel. Proceedings
American Institute of Mining and Metallurgical Engineers.
IV. 160-61. 1953.
13. Faist, C. A. Burnside Steel Foundry Company. Personal
Communication as cited in Air Pollution Aspects of the
Iron and Steel Industry. U. S. Public Health Service Publi-
cation 999-AP-l. Reference 80. p. 109.
14. Douglas, I. H. Direct Fume Extraction and Collection Applied
to a Fifteen Ton,.Arc Furnace. Fume Arrestment - Iron and
Steel Institute - Special Report. 1964. pp. 144,149.
15. Inventory of Air Contaminant Emissions. New York State
Air Pollution Control Board. Table XI. pp. 14-19. Unpublished.
16. Elliot, A. C. and A. J. Freniere. Metallurgical Dust Collection
in Open Hearth and Sinter Plant. Canadian Mining and Metallur-
gical Bulletin. _55(606):724-32. October 1962.
17. Hemeon, C. L. Air Pollution Problems of the Steel Industry.
Informative Report TI-6 Technical Committee. J. of the Air
Pollution Control Association. _U)(3):208-18, March 1960.
18. Coy, D. W. Resources Research, Inc. Unpublished data.
-------
6-20
19. Schueneman, J. J., M. D. High and W. E. Bye. Air Pollution
Aspects of the Iron and Steel Industry. Public Health
Service Bulletin 999-AP-l. 1963. p. 50.
GENERAL REFERENCES
McGannon, H. E. The Making, Shaping, and Treating of Steel.
Pittsburgh: United States Steel Corporation. 8th Edition. 1964.
pp. 29,30,459-545.
Varga, J. , and H. W. Townie. A System Analysis Study of the
Integrated Iron and Steel Industry. Battelle Memorial Institute.
Columbus, Ohio. 1969.
Doerschuk, V. C. How to Control Emissions from Electric Steel
Melting Furnaces. Air Engineering. October 1960.
-------
6-21
6.3 SECONDARY LEAD SMELTING
Process Description
There are three types of furnaces used to produce the common
types of lead. These are the pot furnace for the production of
soft or high purity lead, the reverberatory furnace for the pro- .
duction of semi-soft" lead, and the blast furnace or cupola for hard
lead containing antimony and other metallic impurities. The pot
furnaces are used for the production of the purest of the lead
products. They are usually gas-fired and they operate under more
closely controlled temperature conditions using charges of better
quality lead. Pot furnace air polluting emissions are, therefore,
of a lesser magnitude.
Reverberatory furnaces are used for the production of semi-
soft lead from lead scrap, oxides and drosses. These furnaces
maintain temperatures around 2300°F which favor the production
of sulfur oxides from the sulfur content of the charge and nitrogen
oxides from the fixation of atmospheric nitrogen at these temperatures,
In addition, particulate emissions of lead, tin, copper, and antimony
o
with a particle size averaging 0.3 microns usually occur.
The third common type of furnace, the blast furnace, is used
to produce hard lead (typically averaging 8% antimony and up to 2%
additional metallic impurity). The charge to these furnaces
consists of rerun, slag,*'and reverberatory slags. Emission problems
are greatest with'"this-type of furnace with particulate matter, oil
vapors, and carbon monoxide being emitted.
Factors Affecting Emissions
Factors affecting emissions from the pot furnace include the
composition of the charge, temperature of the pot, and the degree
of control, usually hooding followed by a baghouse applied to the
-------
6-22
system. Emission from the reverberatory furnace is affected by
the content of sulfur in the charge, the temperature in the furnace
(typically around 2300°F) and the amount of air pulled across the
furnace. The off gases here are much hotter than those from the
pot furnace and require cooling before a baghouse can be employed.
Lead blast furnace emissions are dependent on the amount of air
passed through the charge, the temperature of the furnace, and the
amount of sulfur and other impurities contained in the charge.
In addition, significant quantities of carbon monoxide are released
due to the reduction of the lead oxides in the charge by the coke
included in the charge. These emissions, as well as those of oil
vapors and hydrocarbons, must be controlled by incineration. Blast
furnace stack gases, thus, range from 1200-1350°F and must be cooled
before a baghouse can be employed to remove particulates from the
gas stream.
Emissions
Emissions are primarily of particulates consisting of lead,
lead oxides, and contaminants in the lead charged. A particle
size distribution of lead smelting emissions is given in Figure 6.3-1
Emissions from battery lead reclaiming and other reclaiming of
dirty lead scrap can consist of sulfur oxides, hydrocarbons, and
particulates. Carbon monoxide is also released by the reduction1 of
lead oxide by carbon in the cupola. Nitrogen oxides are formed by
fixation of atmospheric nitrogen due to the high temperatures
associated with the smelting. Control of emissions is directed
primarily toward particulates with the bag filter the most common
control device.
Reliability of Emission Factors
Only limited information on smelting emissions was found to
be available at this time. Some information does exist, but is not
available for release at this time. Further information on smelting
emissions should be published as it becomes available.
-------
100
80
60
40-
20
(A
C
o
I 10
: 8
0)
N
'tn
a>
u
I
ro
CO
J
I I 1 I I
I I
I I
.01 O.I 1.0 10 50 90 99.8
Percent by weight less than the stated particle size
Figure 6.3-1. Approximate particle size distribution of participate from
secondary lead smelting6.
99 99
W» *? *F &
-------
Table 6.3-1 Lead Smelting Emissions, Ibs/ton Processes
PartiG,u1atfi:
Furnace Type Uncontrolled Range Controlled Range
Pot Furnace 0.8 0.23-
1.36
Reverberatory
Furnace 130 106-154
Blast (cupola)
Furnace 190 80-181
Rotary Rever- 70 6.6-
beratory 132
Neg
1.6 0.96-
2.33
2.3 0.80-
5.1
s.ox~a
Uncontrolled Range Controlled Range
85
90 64-116
0.8,b 46. 2C
01
I
ro
a) SOX expressed as S02
b) With NaOH scrubber
c) With water spray chamber
-------
Table 6.3-2 Emission Factor Ranking for Lead Smelting Operations
Emission Data Process Data Engineering Evaluation Total
0-20 0-10 0-10
85 5 18
This factor must be considered questionable due to lack of
emission data.
-------
6-26
APPENDIX 6.3
Emission Data from the Literature
(pounds/tpji processed)
BEFORE CONTROL
Furnace- Type
~* '*" *""'
Pot Furnaces
Average
Reverberatory
Furnaces
Rotary, Furnace
Blast (cupola)
Average-
Parti cul ate
0.1
0.34
1.36
0.34
0.68
0.23
0.25-11
0.7?a
106.00
149-154
6.60-132
181
80C
300
187
Ref. S0..b Ref.
X
6
3
4
4
4
4
5
1 26 1
6 149 6
5
1 116 1
2 95.5 2
6 58-64 6
91
a) High value of 11 was not included in average.
b) As S02.
c) A&sumTng baghouse control 99% efficient for particulate emiss'ions,
-------
6.27
Emission Data from;the Literature
(pounds/ton processed)
AFTER CONTROL
Furnace Type Parti cul ate Ref Sp_x_ Ref
Pot Furnaces Neg.
Reverberatory 1.4 6
Furnaces 0.96 1
2.33 3
Average l. 56
Blast (cupola)
Furnaces
Average
3.04
0.80
' 5.1C
~2T33
1
2
0.79
46.20
2b
2a.
a) Spray tower and cyclone control.
b) NaOH scrubbing venturi scrubber.
c) With fabric filter. '
No data was available on CO or NO emissions for secondary lead smelting.
-------
6-28
REFERENCES 6.3
1. , Nance, - O.T. and K. D. Luedtke, Lead Refining. In: Air Pollution-
Engineering Manuals Danielson, J.A. (ed.). National Air Pollution,
Control Administration. Raleigh, North Carolina. Public Health
Sen/tee Publication 999 AP-40, p. 300-304.
2. Pennsylvania State Department of Health. Personal Communication
of Unpublished Stack Test Data, 1969.
3. Allen, G. L., F. H. Viets and L. C. McCabe. Control of Metallurgical
and Mineral Dusts and Fumes in Los Angeles County, California.
Bureau of Mines, Washington, D.C., Information Circular 7627.
April 1952.
4. Private Communication, State of Maryland, November 1969.
5. Restricting Dust and Sulfur Dioxide Emissions from Lead Smelters.
Komrrtission Reinhaltung der Luft (translated from German), Reproduced.
by the U. S. Department of Health, Education and Welfare, Public
Health Service, Washington, D. C., VDI No. 2285. September 1961.
6. Hantnonds W. C. Data on Non-ferrous Metallurgical Operations.
Los Angeles County Air Pollution Control District. November 1966
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6-29
6.4 SECONDARY MAGNESIUM SMELTING
Process Description
Magnesium smelting is carried out primarily in crucible or
pot type furnaces, averaging one ton and less in capacity. .'
Magnesium scrap is charged in a pot or crucible furnace. The
pot or crucible furnace may be fired by gas, oil or electrical
heating. A flux, either gaseous or solid, is used to cover the
surface of the molten metal as magnesium will burn in air at the
pouring temperature (approximately 1500°F). Melts are usually
purified by lancing with chlorine gas. The molten magnesium, usually
cast by pouring into molds, is annealed in ovens utilizing an atmosphere
devoid of oxygen. Usually, this atmosphere consists of sulfur dioxide
maintained at a slightly positive pressure. Losses from this atmosphere
are captured and recirculated to the oven to conserve sulfur.
Factors Affecting Emissions
Factors affecting emissions include the capacity of the furnace,
the type of flux used on the molten material, the amount of lancing
used, and the amount of contamination of the scrap including oil and
other hydrocarbons, and the type and extent of control equipment used
on the process. Typically, hooding is used on the furnaces, and
closed system annealing ovens conserve the sulfur atmosphere used
to prevent the oxidation of the hot magnesium,
Emissions
Emissions from magnesium smelting include particulate magnesium
(MgO) from the furnace melting, oxides of nitrogen from the fixation
of atmospheric nitrogen by the furnace temperatures, sulfur dioxide
losses from annealing oven atmospheres and chloride gases from
-------
6-30
lancing. Carbon monoxide emissions may occur in magnesium reduction
furnaces where magnesium oxide is reduced to magnesium metal by
coke (carbon).
Table 6.4-1 Magnesium Smelting Emissions
Emissions, pounds per ton processed
Furnace Type Particul ate Range
Pot 0.4 0.38-0.46
Reliability of Emission Factors
Emission data from magnesium smelting are extremely limited, and
the factor must be considered questionable.
Table 6.4-2 Emission Factor Ranking
Emission Data Process Data Engineering Evaluation Total
Q-20 0-10 0-10
5 3 5 13
Due to the very limited data available, additional work on
determining both particulate and gaseous emissions is warranted.
-------
6-31
APPENDIX 6.4
Emission Data from the Literature
(pounds/ton processed)
Particulate Ref.
POT Furnace Q.38 1 With Control
0.46 1 With Control
4.4 3
No data were available on CO and NOX emissions from secondary magnesium
smelting operations.
-------
6-32
REFERENCES 6.4
1. ATKejiu G. L., F. H. Viets, and L. C. McCabe. Control of Metallurgical
and (Mineral Duct and Fumes in Los Angeles County, U. S. Bureau
of Mines, Washington, D. C. Information Circular 7627. April 19:52.
2. The %n-Ferrous Scrap Metal Industry, by the National Association
of iSfipondary Material Industries, Inc. 1967.
3. Hanppnd - See Reference 6 previous chapter.
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6-33
6.5 SECONDARY ZINC PROCESSING
Process Description
Zinc processing includes zinc reclaiming carried out by zinc
melting or zinc vaporization, zinc oxide manufacturing typically by
zinc vaporization furnaces, and zinc galvanizing done by dipping
the material to be galvanized in a molten zinc bath. Separations
of zinc from scrap containing lead, copper, aluminum, and iron are
made by careful control of temperature in the furnace allowing each
metal to be removed at its melting range. The furnaces typically
employed are the pot, muffle, reverberatory or electric induction.
These furnaces are oil-, gas- or electrically-fired and must allow
for careful temperature control. Further refining of the zinc cart
be done in retort distilling or vaporization furnaces where the
vaporized zinc is condensed to the pure metallic form. Zinc oxide
is produced by distilling metallic zinc into a dry air stream and
capture of the subsequently formed oxide in a baghouse. Fluxing
is used to clean molten zinc and prevent oxidation when zinc metal
is desired as a final product. Most fluxes do not fume appreciably
if careful temperature control is applied to the furnace. Zinc
fuming can occur if the furnace temperature is allowed to exceed
1100°F. Zinc galvanizing is carried out in vat or bath type dip
tanks utilizing a flux cover. Iron and steel pieces to be coated
are cleaned and dipped into the vat through the covering flux.
Temperatures in the vat are held between 840°F - 860°F.^
-------
6-34
Factors,.Affecting Emissions
Factors affecting emissions from zinc melting include the
type of flux used, temperature in the furnace, amount of organic
material in the charge and the degree to which control of the
generated; fume and particulate is practiced. Factors affecting
zinc vaporization furnaces include the use of carbon as a reducing
agent causing the emission of CO, the amount of organic material
in the charge, the temperature of the furnace residue upon removal,
and the degree to which control is applied to the charging, dis-
tilling^ removal of residue and screening of the residue from
the zinc vaporization operations. Factors affecting emissions
from zinc galvanizing include the temperature of the bath, the
type of flux and method of flux charging on the bath, the amount of
disruption of the flux upon charging of parts to be galvanized, the
amount of dusting of finished pieces with ammonium chloride, and
the amount of control applied to generated emissions from the bath.
Emissions
A potential for emission of particulates, mainly zinc oxide,
occurs if the temperature of the furnace exceeds 1100°F. Zinc
oxide (2nQ) may escape from condensers or distilling furnaces, and
due to its extremely small particle size (0.5 to 0.03 microns),
may pass through even the most efficient collection systems. Some
loss of zinc oxides occurs during the galvanizing processes but
these losses are small due to the flux cover on the bath and the
relatively low temperature maintained in the bath. Some emissions
of partiGlilate ammonium chloride occur when galvanized parts are
dusted after coating to improve their finish. Average particle
size of emissions from galvanizing vats is approximately 2 microns.
-------
6-35
Another source of poten'tial emission of participates and
gaseous zinc is in the tapping of zinc vaporizing muffle furnaces
to remove accumulated slag residue. This slag is hot enough to
generate some zinc fume, and when screened to separate drosses
from solid metal, considerable dust is generated. Emissions of
carbon monoxide occur when reduction of zinc oxide by carbon is '=
done. The potential for emission depends on the amount of charge.
Nitrogen oxide emissions are also possible due to the high
temperatures associated with the smelting and the resulting fixa-
tion of atmospheric nitrogen. Typical pollution control systems
include cyclones, gas cooling units followed by bag-type filters
o
or electrostatic precipitators where oil mist is a problem.
Table 6.5-1 lists the emissions from zinc processing. It
relies on information obtained some years ago because very little
new emission data are available at this time.
'"'*,
Table 6.5-1. Emissions from Zinc Smelting
Emissions - Ibs/ton of product
Furnace^ Type Particulate Range
Retort Reduction 47 20-71.6
Furnace
Horizontal Muffle .,- -Q 60
Galvanizing Kettles 5
Calcining Kiln 89
Pot Furnace 0.1
Sweat Furnace 11
-------
6-36
Reliability of Emission Factors
Very, little data were available on emissions from secondary zinc
smelting operations. Table 6.5-2 presents the factor ranking.
Table 6.5-2. Emission Factor Ranking
Emission Data Process Data Engineering Analysis Total
0-20 0-10 0-10
Particulate 5 4 5 14
Futher work on determining participate and gaseous emission is
warranted!.
-------
6-37
APPENDIX 6.5
Emission Data from the Literature
(pounds/ton processed)
Furnace Type Particulate Reference Number
Retort Reduction 20-50 1
Furnace 71.6 4
Horizontal Muffle
_
Furnace
-------
6-38
REFERENCES 6.5
1. McCabej L C., et al. Control of Metallurgical and Mineral
Dusts and Fumes in Los Anqeles County, California. U. S.
Bureau of Mines. Washington, D. C. Information Circular
7627. April 1952
2. The Ndnferrous Scrap Metal Industry. National Association
of Secondary Materials Industries, Inc. 1967.
3. Thomas, 6. Secondary Zinc-Melting Processes. In: Air
Pollution Engineering Manual. Danielson, J. A. (ed.).
National Air Pollution Control Administration. Raleigh,
North Carolina. Public Health Service Publication 999-AP-40.
p. 293-302.
4. Restricting Dust and Sulfur Dioxide Emissions from Lead
Smelt§rs. Kommission Reinhaltung der Luft (translated from German),
reproduced by the u. S. Department of Health, Education and Welfare,
Public Health Service, Washington, D. C., VDI No. 2285. September
1961.
-------
7. MINERAL PRODUCTS INDUSTRY
Mineral processing is characterized by participate emissions in
the form of dust. Frequently, as in the case of crushing and
screening, this dust is identical to the material being handled.
Emissions also occur through handling and storage of the finished
product since this material is often a dry fine material. Particulate
emissions from some of the processes such as quarrying, yard storage,
and road dust are difficult to control. However, most of the
emissions from the manufacturing processes discussed in this Section,
with the exception of fiber glass, can be reduced by conventional
particulate control equipment such as cyclones, scrubbers, and fabric
filters. Because of the wide variety in processing equipment and
final product, emissions cover a wide range.
Gaseous emissions may occur when the minerals are subjected
to high temperatures such as in calcining or sintering operations.
Fluorides are among the more common gaseous emissions. Gaseous
emissions from fuel combustion also occur when heat is generated
on site.
Particle size data is summarized for those processes
in this section for which such information was available.
-------
7-2
7.1 CERAMIC CLAY MANUFACTURING
Process Description
The manufacture of ceramic clay involves the conditioning
of the basic ores by several methods. These include the
separation and concentration of the minerals by screening,
floating, wet and dry grinding and blending of the desired
ore varieties. The basic raw materials in ceramic clay
manufacture are kaolinite (AlpO-j.ZSiOp.ZHpOjand montmorillonite
(Mg, Ca) O.Al203.5Si02.nH20) clays. These clays are refined by
separation and bleaching, blended and after kiln drying are formed
into such items as whiteware, heavy clay products (brick, etc.)
and various stoneware and other products such as diatomaceous
earth used as a filter aid.
New processes such as halide bleaching for preparation
of kaolinite present an additional potential for air pollution.
This process utilizes the reactivity of the halide to remove
the chemically active and unwanted constituents of the clay
ore leaving behind a purified white product suitable for
ceramics manufacture. See Figure 7.1-1 for a schematic diagram
of this process.
The manufacture of filter and activated clays includes
grinding and wet or acid treating followed by drying and re-
grinding* The drying is accomplished in rotary kilns, which
reduce moisture content from 15-20% to 10%, and the discharge
gases contain high particulate concentrations (4-6 gr/ft.3) as well
as some acid gases and fluorine when this is present in the ores.
-------
Beneficiotion
Raw
Material
t
Trommel
Screen
P-Participates
NO, - NO, N02
F~- Fluoride
Selective
Settling
Bleaching
P, NO..F'
Clay
Fuel
Air, Reaction Gas
Bleached
Product
By product
waste
P, NO*, F~
i ?
Bagging
Clay Storage
Shipment
P, NO., F"
Reacted gas*
* Reaction Gas may include
chlorine and carbon tefrachloride
or other bleaching agents.
I
co
Figure 7.1-1. Ceranic Clay Manufacturing Processes
-------
7-4
Ceramic clay is manufactured from a mixture of wet talc,
whiting* silica clay, and other ceramic materials. This
mixture is dried in an instant spray dryer.
Factors Affecting Emissions
Factors affecting emissions include the amount of material
processed, the type of grinding (wet or dry), the temperature
of the drying kilns, the gas types velocities and flow
direction in the kilns, the amount of fluorine in the ores,
and the type and extent of pollution control equipment
applied to the processes.
Common control techniques include settling chambers,
cyclones, wet scrubbers, electrostatic precipitators and bag
filters. Cyclones for the coarser material followed by wet
scrubbers, bag filters or electrostatic precipitators for
dry dust are the most effective control techniques.
There is no correlation between the various drying
processes and reported emissions. See Appendix 7.1, Table 7.1-3.
Emissions
Emissions consist primarily of particles but some fluorides
and acid gases are also emitted in the drying process. The high
temperatures of the firing kilns are also conducive to the
fixation of atmospheric nitrogen and the subsequent release
of NO . Acid and halide gases from the bleaching of ceramic
clays and the activating of bentonite clays are also emitted
depending on both the amount of acid and excess gas used in the
process and the exit gas velocities. No published information
has been found regarding gaseous emissions from ceramic clay
manufacture.
-------
7-5
Particulate emissions also occur from the grinding
process and storage of the ground product. There is no emission data
in the literature. The emission factors for these operations
2
are based on limited unpublished test data. See Appendix 7.1
for this data. These readings were taken after the dust
collector on the grinding mill exhaust. Whether a collector
was used in the storage area ventilation exhaust is not
known. However, the test results indicate that the readings
were taken after a collector since less than 2.5% of the
emissions are greater than 44 y. The percentage of coarse
particles (> 44y) downstream of the dust collector was found
2
to be as follows:
Drying operation - 13.0%
Grinding operation - 0.6%
Storage bins - 2.3%
Table 7.1-1 lists the factor ranges for particulate emissions
from ceramic clay manufacturing processes.
Table 7.1-1. Emission Factors for Ceramic Clay Manufacture
Particulate Emissions, Ib/ton of input to process
Process No Controls Cyclone a Multiple-unit cyclones & scrubber
Drying 70(14 to 110) 18(4 to 27). 7 (2 to 11)
Grinding 76(64 to 88) 19(16 to 22)
Storage 34(16 to 52) . 8(4 to 13)
a) Approximate collection efficiency 75%; b) Approximate collection
efficiency 90%.
Reliability of Emission Factors
No test data was found to exist for uncontrolled emissions
and the controlled emission data is sparse. Broad ranges are
found to exist even within the same installation. Due to the
-------
7-6
scarcity of particulate emission data and the absence of
gaseous emission data, further testing is warranted. Emission
factor rankings are presented in Table 7.1-2.
Table 7.1-2. Emission Factor Ranking for
Ceramic Clay Manufacture
Emission Data Process Data Engineering Analysis Total
0-20 0-10 0-10
Drying
Grinding
Storage
12
10
4
8
8
8
8
8
5
28
26
17
The factors presented herein for uncontrolled emissions are
based on the major assumption that the collection devices
on which the source tests were made had the following efficiencies:
Cyclone 75%
Cyclone and sprays 80%
Multiple-unit cyclone and scrubber 90%
-------
7-7
APPENDIX 7.1
A. Emissions from Drying Process
The results of nine tests of dryer exhaust gases are
shown in Table 7.1-3. In all cases the readings were taken
downstream of the particulate collection device. Using
the test data, Table 7.1-4 presents uncontrolled emission rates
based on estimated collection device efficiencies and estimated
grain loading of 6 grains/ft.3 upstream of the control device.
Table 7.1-3. Clay Dryer Particulate
Emissions Test Data
Gas
Test Process Collection Gas Volume,
No. Equipment Device Temp.,°F scfm
Process Parti -
Wt. cul ate Reference
Ib/hr Ib/hr Number
1
2
3
4
5
6
7
8
9
Dryer
Rotary
dryer
Ki 1 n &
cooler
it
Instant
spray
dryer
Rotary
dryer
n
n
n
Cyclone &
sprays
Multiple-
unit
cyclone &
wet scrubber
Cyclones
Cyclones
ii
M
n
66
109
159
160
244
-
-
-
_
23800
17600
23900
27300
10500
-
-
-
-
15000
29300
31000
31000
3300
10000
10000
10000
10000
20.7
56.1
127.0
92.4
24.8
28.8
128
135
85.1
1
1
1
1
1
2
2
2
2
-------
7-8
Table 7.1-4.
Estimated Uncontrolled Particulate Emissions
from the Clay Drying Process
Test Estimated eff.
No. of collector, !
Controlled Uncontrolled Emissions, Ib/ton of input
Emissions Based on Collector Based on 4-6 gr/ft.3
Ib/ton of Efficiency loading
input
1
2
3
4
5
6
7
8
9
Average
Range
80
90
90
90
75
75
75
75
75
2.8
3.9
8.2
6.0
15.0
5.8
25.6
27.0
17.0
3 to 27
14
39
82
60
60
23
102
108
68
61.8
14 to 110
107 to 160
43 to 66
63 to 94
71 to 106
290 to 430
-
-
-
-
74 a
43 - 110a
a) Not including Tests No. 1 and 5
Particulate loss on drying has been estimated to be
13.8 Ib/ton^ and 14.4 Ib/ton . These figures tend to agree
with estimated emissions for Tests No. 1 and 6 above. Note,
however,that the emissions based on estimated grain loadings
do not correlate well for Tests No. 1 and 5.
Based on the above data, an uncontrolled factor of
70 Ibs/ton was chosen.
-------
7-9
B. Emissions from Grinding Process
Table 7.1-5 presents test data taken from a clay grinding
2
mill. Three separate tests were run on the same facility.
The test port was located downstream of the cyclone collector.
2
Table 7.1-5. Particulate Emissions from a Clay Grinding Mill
Feed Rate,
tons/hr
5
5
5
Range
Ib/hr
111.3
81.8
81.5
Controlled Emissions3
Ib/ton
22.2
16.3
16.3
16-22
a) Measured after cyclone collector.
Assuming a collection efficiency of 75%, 'the uncontrolled
emissions would range from 64 to 88 Ib/tonwith an average of 76.
C. Emissions from Storage Bin
Table 7.1-6 presents test data taken from a storage bin
area of the ceramic clay manufacturing installation tested above.
The operating production rate was 5 tons/hr. A collector having
a 75% efficiency was assumed to be in use with the test readings
taken downstream of such collector.
2
Table 7.1-6. Particulate Emissions from Ground Clay Storage Bin Area
Feed Rate, Control1edaEmissions
tons/hr Ib/hr Ib/ton
5 65.1 13.0
5 20.4 4.1
5 27.2 5.4
Range 4 to 13
a) Assumed.
-------
7-10
Based on a collector efficiency of 75%, the uncontrolled
emissions would range from 16 to 52 Ib/ton with an average
of 34.
-------
7-11
REFERENCES 7.1
1. Allen, G.L., F.H. Viets, and L.C. McCabe. Control of
Metallurgical and Mineral Dusts and Fumes in Los Angeles
County, California. Bureau of Mines. Washington, D.C.
Information Circular 7627. April 1952. p. 65-68.
2. Private Communication with the State of New Jersey Air" :
Pollution Control Program, Trenton, N.J. July 20, 1969.
3. Henn, J.J., et al. Methods for Producing Alumina From
Clay, An Evaluation of Two Lime Sinter Processes. Bureau
of Mines. Washington, D.C. Report of Investigations 7299.
September 1969.
4. Peters, F.A., et al. Methods for Producing Alumina From
Clay, An Evaluation of the Lime-Soda Sinter Process.
Bureau of Mines. Washington, D.C. Report of Investigations
6927. 1967.
GENERAL REFERENCES
Shreve, R.N. Chemical Process Industries, 3rd Edftion,
New York. McGraw Hill Book Co. 1967. p. 143-149.
-------
7-12
7.2 BRICKS AND RELATED CLAY PRODUCTS MANUFACTURING
Process Description1'2'3
The manufacture of brick and related products such as clay pipe,
pottery and some types of refractory brick involves the grinding,
screening, blending of the raw materials; forming, drying or curing,
firing, and final cutting or shaping. Particulate emissions occur
during handling of raw materials, grinding, screening and blending,
and during cutting and shaping operations. Gaseous emissions occur
from the curing and firing operations.
Refractory brick may be formed by pressing at high pressure,
after the raw material is blended and mixed with various binders.
The formed brick is then fired at temperatures in excess of 3000°F
in long tunnel ovens. Most of the refractory brick manufactured in
the United States is either silica (acid) or fire-clay (neutral).
Silica brick contains 95-96% silicon dioxide and about 2% lime, and
is formed by high pressure pressing. Fire clays are made from
clay and vary in composition from those with high silica content to
those with high alumina content. The relatively small amount of basic
refractories manufactured include magnesia, chromite, and mixtures
of magnesia and silicon dioxide.
The drying and firing of pressed bricks, both common and refractory,
is accomplished in many types of ovens. The most popular type is the
long tunnel oven in which the bricks, loaded on steel carts, pass
counter-currently against the heat flow. Total heating time varies,
but is usually 50-100 hours for 9 inch refractory bricks. Normally
gas or oil fuel is used for heating., but coal may be used. Temperatures
up to about 2000°F are used in firing common brick.
-------
7-13
Common brick or building brick is prepared by molding a wet mix
(20-25% water, 75-80% clay) followed by baking in chamber kilns at
1600-1800°F. Common brick is also prepared by extrusion of a stiff
mix (10-12% water), followed by pressing and baking of the sections
cut from the extrusion. These operations using large quantities of
water are not major sources of dust.
Factors Affecting Emissions
The extent of raw material handling and processing, and the
degree of control on these operations greatly affect the dust emissions
from this part of the manufacturing process. Emissions when firing
and/or curing the formed bricks are affected by the temperature in
the ovens and the type and quantity of trace components in the brick.
Thus, sulfur and/or fluoride compounds may be emitted when the bricks
are subjected to high temperatures. The type of fuel used to heat
the ovens also has a direct bearing on the combustion emissions.
Emissions
Particulate emissions, similar to those obtained in clay processing
(Section 7.1) are emitted from the materials handling process in^a
refractory and brick manufacturing.
Combustion products from the fuel consumed in the curing, drying,
and firing portion of this process are also emitted. Approximately
fi <3
3-4 x 10 Btu of heat are required per ton of. brick produced.
Nitrogen oxide emissions were therefore estimated^based on emission
factors available for fuel combustion in boilers (S§e>Appendix 7.2).
Fluorides, largely in a gaseous form, are also emitted from brick
4
manufacturing operations. Sulfur dioxide may also be emitted from
the bricks when firing temperatures of 2500°F or more occur, or when
the fuel contains sulfur.
-------
7-14
A variety of control systems may be used to reduce both parti cul ate
and gaseous emissions. Almost any type of particulate control system
will reduce emissions from the material handling process. However,
good design, and hooding are required to keep emissions to a minimum.
Fluoride emissions can be reduced to very low levels by using a
water scrubber.
Table? 7.2-1 presents the emission factors for brick manufacturing.
Table 7.3*1;. Uncontrolled Emissions From Brick Manufacturing,
_ Ibs per ton of product _
Process Particulate Fluoride3 NO
Raw Material;
Handling0 -. Drying 70 (14 to 110)
Grinding 76 (64 to 88)
Storage 34 (16 to 52)
Curing and Firing
a)
b)'
c)
Gas Fired
Oi.l Fired
Coal Fired 5A
Expres£e4, as HF and based
percent fluoride.
Expressed? as NO^.
Based, on: Reference 8.
Neg.
Neg.
to 10Ad
on a raw material
0.8
0.8
0.8
content of
0.6
1.3
1.5
0.05 weight
d) A >s the percent ash in the coal and gives the emission on a
Ibs per ton of fuel used basis. This is an estimate based
on coa.l-fired furnaces.
-------
7-15
Reliability of Emission Factor
Limited data are available on gaseous emissions from brick and
related clay product manufacturing processes. The raw material handling
processes used at any particular installation could vary widely.
Emission factors for these processes are, however, considered reliable
(Section 7.1). Emissions from curing and firing of clay products
are based on very limited data and are considered questionable as
shown in Table 7.2-2.
Table 7.2-2. Emission Factor Ranking for Bricks
Emission Data Process Data Engineering Analysis Total
0-20 0-10 0-10 '
2 55 12
Nitrogen oxide emissions were based on the fuel consumption used
in firing bricks and on emission factors used for boilers.
-------
7-16
APPENDIX 7.2
Nitrogen oxide emissions may be estimated based on a heat
fi o
consumption of 10 - 12 x 10 Btu per 1000 bricks, and on existing
emission factors for fuel combustion. Combustion chamber temperatures
in brick ovens and boilers are similar, but excess air rates are
usually lower in the ovens. Therefore, use 0.75 of existing NO
X
emission factor for industrial boilers. One thousand bricks weigh
about 3 tons,* therefore, 3 - 4 x 10 Btu are required to treat
1 ton of brick.
NO emission factors for Industrial Boilers '
/\
Gas- Fired 214 lbs/106 ft3 = 0.214 lbs/106 Btu
Oil- Fired 72 lbs/1000 gal = 0.5 lbs/106 Btu
Coal-Fired 15 Ibs/ton = 0.58 lbs/106 Btu
Emissions from brick firing ovens may be estimated as follows:
Gas- Fired 0.214 lbs/106 Btu x 3.5 x 106 Btu/ ton x .75 = 0.56 Ibs/ton
Oil-Fired 0.5 lbs/106 Btu x 3.5 x 106 Btu/ton x .75 =1.3 Ibs/ton
Coal-Fired 0.58 lbs/106 Btu x 3.5 x 106 Btu/ton x .75 = 1.5 Ibs/ton
HF emissions from brick baking : based on 500 ppm F~ by weight
in the clay and 80% evolved at a temperature of 1800°F of higher, the
emission would be:
1 ton cla.y x 2000 Ibs/ton x 500 x .80 = 0.8 Ibs F"/ton of brick.
o o
a) Bricks weigh about 110 Ibs/ft and each brick occupies 0.058 ft ,
one brick thus weighs about 6.45 Ibs (Reference 4).
-------
7-17
REFERENCES 7.2
1. Shreve, R.N. Chemical Process Industries, 3rd Edition.
New York, McGraw-Hill Book Company. 1967. p. 151-158.
2. Havighorst, C.R. and S.L. Swift. The Manufacture of Basic
Refractories. Chem. Eng. 72_: 98-100, August 16, 1965.
3. Norton, F.H. Refractories, 3rd Edition. New York, McGraw-Hill
Book Company. 1949. p. 252.
4. Marks, L.S. (ed.). Mechanical Engineers' Handbook, 5th Edition,
New York, McGraw-Hil:,l Book Company. 1951. p. 523 and 535.
5. Duprey, R.L. Compilation of Air Pollutant Emission Factors.
National Air Pollution Control Administration, Raleigh, North Carolina,
Public Health Service Publication 999-AP-42. p. 6 and 7.
6. Supra, 2.2.
7. Semrau, K.T. Emission of Fluorides from Industrial Processes.
A Review. 0. Air Pollution Control Association. 7_(2):105,
August 1957.
8. Supra, 7.1.
-------
7-18
7.3 CASTABLE REFRACTORIES MANUFACTURING
1 2
Process Description '
Castable or fused-cast refractories are manufactured by
carefully blending such components as alumina, zirconia, silica,
chrome, and magnesia, melting the mixture in an electric arc
furnace at temperatures of 3200-4500°F, pouring into molds, and
slowly cooling to the solid state.
Fused refractories are less porous, and more dense than
kiln-fired refractories.
Particulate emissions occur from the drying, crushing,
handling, and blending phases of this process; the actual
melting process; and in the molding phase. Fluoride emissions
largely in the gaseous form may also occur during the melting
operations.
The general types of particulate controls may be used
on the materials handling aspects of refractory manufacturing.
However, emissions from the electric arc furnace are largely
condensed fume and consist of very fine particles, largely
3
2 microns or smaller. Fluoride emissions can be effectively
controlled with a scrubber.
Factors Affecting Emissions
Particulate emissions are affected by the amount of
material handling and pre-treatment required before melting,
and by the components in the melt. Generally, increasing
concentrations of silicon will cause increased particul ate
emissions. The effectiveness of hooding and control equipment
wills of course, have a direct bearing on emissions.
-------
7-19
Fluoride emtssions are a direct function of the feed's
fluoride content. Dry type particulate collectors will have
little effect on fluorides.
Emissions
Emission fadtors based on the data presented in Appendix 7.3
are shown in Table 7.3-1 for the various processes involved
in cast refractories manufacturing.
Table 7.3-1. Particulate Emissions from
Castable Refractories Manufacturing
Process
Emissions, Ibs/ton of feed material
Uncontrolled Controlled Type of Control
Raw Material Dryer
Raw Material Crushing
and Processing
Electric Arc Melting
Curing Oven
Molding and Shakeout
30
120 (100-190)
50 (10-88)
Neg.
25
0.3
7
45
0.8
10
0.3
Baghouse
Scrubber
Cyclone
Baghouse
Scrubber
Baghouse
Fluoride emissions from the melting operation averaged
1.3 pounds of HF per ton of melt with a range of 0.7 to 1.9 pounds
per ton.
* .
Reliability of Emission Factors
Emission factors for cast refractories are based on
limited data and cover a wide range. Variations in processes
and at the various plants, and in the composition of the product
account for some of this variation. Table 7.3-2 presents the
factor rankings and shows the factors to be questionable.
-------
7-20
Table 7.3-2. Emission Factor Ranking
for Cast Refractories
Emission Data Process Data Engineering Analysis Total
0-20 0-10 0-10
Parti eul ate
Fluoride
7
5
4
3
3
3
14
11
Additional work appears warranted in this area because of
the large amount and small particle size of particulate emissions,
and the possibility of fluoride emissions.
-------
7-21
Process
APPENDIX 7.3
Table 7.3-3. Particulate Emission Data for
Castable Refractories
Emission, Ibs/ton of feed
Reference
Raw Material Dryer
Raw Material Crushing,
Screening, Blending
Electric Arc Furnace
Melting
Molding and Shakeout
Curing Oven (if used)
Uncontrolled
30
102
189
88
10-70
11*
55*
Avg. 47
25
0.2
Type of Controlled
Control
Baghouse
Roto clone
Cyclone
Baghouse
Scrubber
Baghouse
Baghouse
-
0.3
6
76
0.9
ga
0.5a
0.25
-
4
4
5
4
5
3
3
4
5
a) Emissions were measured, but process weight was estimated based
on furnace size.
Fluoride Emission Data
From electric arc melting process, pounds of HF/ton
Uncontrolled Type of Control Controlled
0.7 Scrubber 0.005
1.9 Baghouse 1.7
Avg. 1.3
-------
7-22
REFERENCES 7.3
1. -Brown, R.W. and K.H. Sandmeyer. Applications of Fused-Cast
Refractories. Chem. Eng. 76;106-114, June 16, 1969.
2. Shreve, R.N., (ed.). Chemical Process Industries. 3rd
Edition. New York. McGraw Hill Book Co. 1967. p. 158.
3. Resources Research, Inc. Stack Test Data, 1967.
4. Personal Communication. M. McGraw. Division of Air Quality
and Emission Data, National Air Pollution Control Administration.
November 1969.
5. Resources Research, Inc. Stack Test Data, 1969.
GENERAL REFERENCE
Buf'st, J.F., and J.A. Spieckerman. A Guide to Selecting
Modern Refractories. Chem. Eng. 74:85-104, July 31, 1967.
-------
7-23
7.4 STONE QUARRYING AND PROCESSING
Process Description
Rock and gravel products are loosened by drilling and
blasting from their deposit beds and removed with the use of
heavy earth moving equipment. This mining of rock is done
primarily in open pits. The use of pneumatic drilling and
cutting as well as the blasting and transferring cause considerable
dust formation. Further processing includes crushing, screening,
regrinding, and removal of fines. Dust emissions can occur
from all of these operations as well as from quarrying,
transferring, loading, and storage operations. Drying operations,
when used,can also be a source of dust emissions.
An additional major source of air pollution at these
plants is the traffic of heavy equipment over unpaved dusty
surfaces. The control of this dust is very difficult and is
usually handled by wetting of traveled areas with oil or water.
Paving has had limited success in dust control in that dust
accumulates on the paving and is thus recirculated to the
atmosphere by the traffic over the pavement. Common controls
of these operations include cyclones and fabric filters or
scrubbers on processing machinery, and dust suppression through
cleaning and wetting traveled surfaces. Cyclones can achieve
an efficiency of about 80% while fabric filter systems can collect
99% of the dust vented from the process equipment. Approximately
10-15% of dust generally escapes the hooding and ventilation
2
systems.
-------
7-24
Factors Affecting Emissions
Factors affecting emissions include the amount of rock
processed, the method of transfer of the rock, the moisture
content of the raw material, the degree of enclosure of the
transferring, processing or storage areas, and the degree to
which control equipment is used on the processes. The amount
of vehicular traffic and the method and degree of control of
dust generated by traffic in the plant also affect emissions.
Emissions
Limited particulate emission data are presented in Table
7.4-1. These data are based on the amount of particulate
collected in a baghouse control system. While individual process
emissions are only crude estimates, the overall plant emission
is representative of these variable emissions. Particle size
data are presented in Figure 7.4-1.
The data presented in Table 7.4-1 based on reference 2
is based on the dust collected at processes controlled by fabric
filter systems. The quantity of dust collected was then
correlated with the process throughput. These factors have an
estimated range of about ±25%.
2
Table 7.4-1. Uncontrolled Emissions From Rock Handling Processes
Process Estimated Atmospheric Emission. lbs/tona
Primary Crushing
Secondary Crushing
& Screening
From Process
0.5
1.5
% Settled Out
in Plant
80
60
Suspended
Emission
0.1
0.6
Tertiary Crushing & 6.0 40 3.6
Screening (if used)
Recrushing & Screening 5 50 2.5
Fines Mill _6 25 4.5
TOTAL 19.0 11.3
a) All values are based on raw materials entering primary crusher except
for recrushing and screening which is based on throughput for .that
operation. Typical collection efficiencies: Cyclone 70-85&;
-------
I
r>o
Ui
O.I
10 50 90
% BY WEIGHT LESS THAN STATED SIZE
9999
Figure 7.4-1. Participate size from rock processing operations3
-------
7-26
Storage pile losses due to wind erosion have been estimated
at about 1% of product.4 While this figure is probably representative
of sand and other finer material, it is thought to be too high
for rock and gravel storage. A value of about 0.5% of the
finished product is probably closer to the wind losses from
rock and gravel storage piles.
Particulate emissions from dryer operations also occur.
Normally dryers are not used, but for some minerals such as
dolomite they are required. These units are usually direct fired,
either parallel or counter flow, rotary dryers. Particulate
emissions from a dolomite dryer have been reported in the
2-50 Ib/ton of product range after a cyclone type collector.5
General screening, conveying, and handling losses have been
estimated to be 1,7 pounds per ton.
Ambient air data around rock processing plants have been
reported and are summarized in Table 7.4-2.
Table 7.4-2. Ambient Air Particulate Concentrations Around a
Rock Quarrying and Processing Plant
- Production Rate of 600 - 700 tons/hr
Distance From Average Dustfall Average Daily
Center of Plant, 2 Suspended ParticuTate
Feet Tons/Mile/Month*3
0
18000
2,500
40000
5,000
225
78
15
13
8
50 - 130*
* During plant shut-down, a value of 35 ygm/M was obtained and
during periods of inversions, values as high as 954 were obtained.
-------
7-27
Reliability of Emission Factors
Actual source test data is limited and would vary widely
depending on plant design and operation. Ambient air conditions
around this type of operation have been monitored, and information
is available. Further work in this area must include source
testing and engineering analysis. The factors given here must
be considered questionable. Factor ranking is presented in
Table 7.4-3.
Table 7.4-3. Emission Factor Ranking for Stone Processing
Emission Data Process Data Engineering Analysis Total
0-20 0-10 0-10
5 7 5 17
Appendix was not included in this Section, since large
quantities of emission data were not found, and no calculations
were involved.
-------
7-28
REFERENCES 7.4
1. Personal Communication, National Crushed Stone Association,
Sept. 1969.
2. Memo from P. Culver to File, Abatement Division, National
Air Pollution Control Administration. January 6, 1968.
3. Duprey, R.L. Particulate Emission and Size Distribution
Factors. National Air Pollution Control Administration.
Unpublished Data Prepared for New York - New Jersey Air
Pollution Abatement Activity, May 1967.
4. Sussman, V.H. Nonmetallic Mineral Products Industries. In:
Air Pollution Vol. III. Stern, A.C. (ed.). New York. Academic
Press. 1968 p. 123-127.
5. Cross, F.L., and R.W. Ross. Field Control of a Dolomite
Plant. J. Air Pollution Control Association. 18:27-29,
January 1968.
6. Private Communication. Sableski, J.J. National Air Pollution
Control Administration. May 1967.
)
GENERAL REFERENCES
Minnick, J.L. Air and Water Pollution as Affecting the Stone
Industry. Presented at 50th Anniversary Convention - National
Crushed Stone Association, 1967.
Anderson, F.6., and R.L. Beatty. Dust Control in Mining, Tunneling,
and Quarrying in the United States 1961-1967. U.S. Bureau of
Mines #8407. 1969.
Levine, S. What You Should Know About Dust Collectors. Rock
Products, April 1965.
Soderberg, H.F. Keep That Crusher Dust Down. Metal Mining and
Processing, September 1964.
-------
7-29
7.5 GYPSUM MANUFACTURING
General Information
Gypsum or hydrated calcium sulfate is a naturally occurring
mineral which is found in large deposits throughout the world. With
its fire resistance, structural strength, adaptability to design, ,
ease of handling and ready availability, gypsum has been an important
building material for nearly four thousand years. When heated,
gypsum loses its water of hydration and becomes what is commonly
known as plaster of paris, which is used for casts and stucco work.
When blended with fillers such as lignin or starch, the calcined
gypsum serves as wall plaster. In both cases the material hardens
12
as water reacts with it to form the solid crystalline hydrate.
Gypsum is very widely distributed in the United States. \ The
largest producing states are Michigan, New York, Iowa, and California,
but there are also extensive deposits in Kansas, Ohio, Wyoming,
3
New Mexico, Virginia, Texas, Nevada, and Montana. In 1967, there
were 76 active gypsum calcining plants in the United States, and
nearly 8 million short tons of calcined gypsum were produced with
4
a value of over 115 million dollars.
1 5
Process Description *
Calcination of gypsum to first-settle plaster (plaster of paris)
occurs according to the following reactions:
2(caS04 2 H2o)+ (CaS04)2 H2C +3 H20 AH25 = +33.0 Kcal
The usual method of calcination of gypsum consists of grinding the
mineral to about 90% minus 100 mesh and placing it in large externally
heated calciners holding 10 to 25 tons. The calciners are usually
large kettles, but rotary kilns are sometimes used. In the kettle
process, the pulverized gypsum is placed in a vertical cylindrical
kettle which is 8 to 10 feet in diameter and depth. The center of
the bottom is about one foot higher than the sides. The temperature
-------
7-30
is raised to 120 to 150°C (250 - 300°F) and the material is stirred
with a heavy blade closely conforming to the bottom of the kettle.
External heat is applied directly to the kettle bottom, and hot gases
rise around the sides and also pass through flues higher up in the
kettle. Complete calcination takes about 3 hours. The material in
the kettle, known as plaster of paris or first-settle plaster, may
be heated further to 190°C (375°F) to produce a material known as
second-settle plaster. First settle plaster is approximately the
half-hydrate, CaS04 /2 hUO, while second-settle plaster is
anhydrous.
The more modern rotary kiln method involves heating crushed
gypsum rock in rotary kilns and dropping the hot material into concrete
bins lined with firebrick, where calcination reaches the hemihydrate
stage, CaS04 V2 H20.
The finished product may be passed through mechanical air
separators (cyclone) to segregate the material before packaging.
Approximately 1.0 million Btu are required to calcine 1 ton
of plaster.5'9
Factors Affecting Emissions
The major factor affecting particulate emission's from the actual
calcining process is the calcination rate which in turn determines the
emission rate of the escaping gases. Particle size of the gypsum
and-degree of agitation are other factors affecting particulate
emissions during calcination. In general, emissions from a direct-
fired rotary kiln are greater due to the added agitation in the kiln
caused by the fuel's combustion products.
-------
7-31
Dust emissions resulting from the grinding of the gypsum before or after
calcining and from the mixing of the calcined gypsum with filler are
also affected by particle size and degree of agitation.
Emissions
Calcining gypsum appears at first glance to be devoid of any air
pollutants, since the process involved is simply the relatively low
temperature removal of the water of hydration. However, the resultant
gases created by the release of the water of crystallization carry
gypsum rock dust and partially calcined gypsum dust into the
atmosphere in.a steamy, dusty condition. For each ton of gypsum
o
calcined, there are 314 pounds of water vapor liberated (6600 ft ).
In addition, dust emissions from the grinding of the gypsum before
calcining, and from the mixing of the calcined gypsum with filler
also occur.
Ninety-five percent of gypsum dust particles emitted from the
calcining process are smaller than ten microns in diameter and grain
loadings from handling and conveying range from 1.5 - 5.0 grains per
cubic foot of exhaust.
Table 7.5-1 presents limited emission data based on actual plant
estimates and measurements. This table incorporates all the data
found, and no appendix is included in this chapter.
-------
7-32
Table 7.5-1. Particulate Emissions From Gypsum Processing, Ibs/ton throughput8
1. Raw Material Dryer (if used)
a. Uncontrolled
b. Fabric Filter
c. Cyclone and Electrostatic Precipitator
Emission
40 (4 to 80)
Negligible to 0.3
0.4
2. Primary Grinder (if used)
a. Uncontrolled
b. Fabric Filter
1
0.001
3. Calciner
a. Uncontrolled
b. Fabric Filter
90 (87 to 93)
0.13
4. Conveying
a. Uncontrolled
b. Fabric Filter
0.7
0.001
Total uncontrolled emissions thus vary from about 93 to 175 Ibs/ton
w_4th controlled emissions of about 0:15 Ibs/ton. An average
uncontrolled factor of about 130 Ibs/ton of raw material input for
a large integrated plant can be used for general estimating purposes
with a range of - 30%.
Reliability of Emission Factor
Due to limited emission data and the lack of process information
required to perform engineering analysis, the emission factors for
gypsum processing must be classified as questionable as ranked in Table 7.5-2.
Table 7.5-2. Gypsum Emission Factor Ranking
Emission Data
0-20
Process Data
0-10
Engineering Analysis
0-10
Total
-------
7-33
REFERENCES 7.5
1. Shreve, R.N. (ed.). Chemical Process Industries, 3rd Edition.
New York, McGraw-Hill Book Company, 1967. p. 180-182.
2. Havinghorst, R. A Quick Look at Gypsum Manufacture. Chem. Eng.
71:52-54, January 4, 1965.
3. Gypsum. The Encyclopedia Americana. 13_:592-593, 1957.
4. Gypsum. Minerals Yearbook: U.S. Dept. of the Interior, Bureau
of Mines, Washington, D.C., 1-2: 552, 1967.
5. Work, L.T. and A.L. Stern. Size Reduction and Size Enlargement.
Chemical Engineers' Handbook, 4th Edition. Perry, J.H. (ed.).
New York, McGraw-Hill Book Company, 1963. Chap. 8, p. 51.
6. Culhane, F.R. Chem. Eng. Progress. 64_:72, January 1, 1968.
7. Magill, P.L., F.R. Molden, and C. Ackley. Gypsum Storage,
Conveying, and Handling. Air Pollution Handbook, New York,
McGraw-Hill Book Company, 1956. Chapter 13.
8. Private Communication. Maryland State Department of Health,
November 1969.
9. Private Communication. Hambuik, M.M. Gypsum Assoc. Chicago, 111.
January 1970.
GENERAL REFERENCES
Calcium Compounds. Kirk-Othmer Encyclopedia of Chemical Technology,
2nd Edition, 4:18, 1964.
Taeler, P.H. Gypsum Plant by - the - Number, Minerals Processing.
p. 15-19, January 1967.
-------
7-34
7.6 CLAY AND FLY ASH SINTERING
General Information
The use of sintered fly ash in the manufacture of light-
weight masonry products has been a potential solution to the
difficult disposal problem facing large coal-burning operations.
Fly ash cannot simply be dumped. Due to its extreme lightness it
must be covered with soil and vegetation, or treated and disposed
of in a subterranean site. Conventional fly ash disposal costs
range from $0.60 to $2.00 per ton. However, sintered fly ash
may be sold for more than $5.00 per ton.
Clay, on the other hand, does not present a disposal problem,
but its natural characteristics render it desirable for sintering
purposes.
The predominant use of sintered clay is for concrete building
products. Sintering drives off the volatile matter within the
pellet thereby creating macroscopic voids and creating a strong
bond between clay particles. This process reduces the weight of
the clay material by approximately 20 to 30%, and the sintered
2
product weighs 1200 Ibs per cubic yard.
Process Description
While the processes for sintering fly ash and clay are generally
similar, some distinctions exist which justify a separate discussion
of each process.
-------
7-35
Fly ash sintering plants are generally located near the source -
the fly ash being delivered to a storage silo at the plant by a
closed pneumatic system. The storage silos generally have bag-type
filters to control dust. The dry fly ash is moistened with a 1%
water solution of lignin or other binding agent and agglomerated
into pellets, balls, or other convenient shapes generally less than
1 inch in circumference. The material then goes to a traveling
grate sintering machine, where direct contact with hot combustion
gases at 2300°F sinters the individual particles of the pellet
and completely burns off the residual carbon in the fly ash. After
sintering, the product is crushed since the individual pellets
normally fuse together into clusters. Finally, the material is
screened, further crushed as required, graded and stored in yard
31 11
piles. The typical aggregate grades are /. - /^ inch, /, - /g inch,
and less than /g inch. Figure 7.6-1 illustrates a typical fly
ash sintering operation.
As was previously stated, clay sintering involves the driving
off of entrained volatile matter.
It is desirable that the clay contain a sufficient amount of
volatile matter in its natural state. Should the sintered clay not
contain enough volatile matter,the resultant aggregate will be too
heavy. Thus, in areas where the natural clay contains insufficient
amounts of volatile matter, it is necessary to mix the clay with
finely pulverized coke. Some sources require that up to 10% coke
23
by weight be added. ' To sinter clay, it is first mixed with pulverized
coke, if necessary, and then pelletized. After pelletizing, the
clay is sintered in a rotating kiln, or on a traveling grate by
direct contact with hot combustion gases at 1950 - 2200°F. The
sintered pellets are then crushed, screened, and stored, similar to
fly ash pellets.
-------
7-36
Fly Ash
Storage
Silo
1
1 % Water
Drying ft Sintering
Machine
Product
Hopper
Crusher
Figure 7.6-1. Fly Ash Sintering
-------
7-37
Factors Affecting Emissions
For both fly ash and clay sintering, the major factor affecting
participate emissions, in addition to plant throughput, is plant
design and maintenance. Each process will be discussed separately.
Fly ash will, if improperly handled, create an air pollution
problem. Adequate design features including fly ash wetting systems,
and particulate collection systems on all exit stack-conveyor belt
transfer points and on crushing and screening operations will greatly
reduce emissions.
Normally fabric bag filters are used to control emisstio^s from
the storage silo. The absence or malfunction of this dust collection
system would create a major emission problem.
Upon discharge from the silo to the agglomerator, moisture
is added and very little emission occurs between the storage silo
and the sintering machine. However, emissions do vary with the
type of conveying system used. If an open belt is used between these
points, efficient water sprays must be utilized at the silo
discharge.
Normally, there is little emission in the sintering machine.
However, it is important that the traveling grate be properly
maintained. If the grate is defective, dried pellets will drop
through the grate. These pellets will then break and create dust
particles which are carried along in the exit gas stream. The speed
of grate travel is also important since dryipg too rapidly or raising
the temperature too quickly will cause the pellets to crumble. Down-
draft sintering machines inherently produce less emissions due to
the basic design feature which directs the hot gas stream downward.
Continuity of operation also affects emissions since the low temperatures
experienced during start-up will result in a brittle pellet which
crumbles and drops through the grate.
-------
7-38
After sintering, the crushing, screening, handling, and storage
of the sintered product creates dust problems. These emissions are
usually controlled with scrubbers on the crushers and water sprays
as required at the various handling points and in the yard.
In general, a dust problem arises at points of transfer where
sufficient hoods and venting are not provided or where skirts are
inadequately designed. While strategically placed water sprays
will help keep the dust down, it is important that all dry fly ash
handling be done by means of enclosed conveyors.
Scrubbing systems on the crushing and screening operations,
proper conveyor belt design, and liberal use of water sprays can
reduce these emissions an estimated 90%.
Emissions from the combustion process also occur. The fuel is
usually light oil or gas and the gaseous emissions may be estimated
4
from available factors. No correlation between fuel use and
finished product is available.
The addition of pulverized coke, when sintering clay, presents
an emission problem. If the coke pulverizing system is improperly
maintained, it can be a major source of particulate emission. Also,
the sintering of coke impregnated dry pellets produces more particulate
emissions than the natural clay. In a traveling grate sintering
machine, the direction of the hot process gases also affects emissions.
For example, if the gas flows downward through the grate, particulate
emissions will be less than from an updraft unit which discharges
after one pass.
The crushing, screening, handling, and storage of the sintered
clay pellets creates dust problems similar to those encountered in
fly ash sintering.
-------
7-39
Emissions
Results of source testing of fly ash sintering operations have
not been reported. However, a yield of 90% has been reported in the
literature. Another plant has estimated an 83% yield based on a
fly ash carbon content of approximately 7%. Assuming that about
half of the difference may be airborne, the potential particulate
emission may range from about 4 to 5% of input, or 5 to 6% of
finished product (100 to 120 Ib/ton). These losses include yard
losses of the finished product due to wind.
Limited source test data and engineering analysis have been
found for clay sintering processes. From this information, emission
factors have been calculated. (See Appendix 7.6 for detailed calculations).
In addition to the actual sintering operation, particulate losses
occur from crushing, screening, and storing the sintered product.
Table 7.6-1 lists the emission factors for sintering of fly ash
and clay.
Table 7.6-1. Emission Factors for Sintering Operations
Type of Sintering Particulate Emissions, Ib/ton of finished product
Operation Sintering Operation6 Crushing, Screening
and Yard Storage
Fly Ash 110 (100 to 120) d
Clay Mixed with Cokea 40 (25 to 65) 15
Natural Clayb 12 (10 to 14) 12
a) 90% clay, 10% pulverized coke; traveling grate, single-pass
up-draft sintering machine.
b) Rotary dryer sinterer.
c) Estimated* based on data-in Reference 6.
d) Included in sintering losses.
e) Cyclone's would reduce this emission by about 80%,
Scrubbers would reduce this emission by about 90%.
-------
7-40
Reliability of Emission Factors
Due to the limited process data and emission data available and
the general lack of source testing data, the emission factors for
fly ash and clay sintering are questionable. Emission factor rankings
are presented in Table 7.6-2. Further work in this area is necessary
to provide more realistic factors. The reported factors are felt
to be correct - 50%.
Table 7.6-2. Emission Factor Rankings for Sintering Processes
Emission Data Process Data Engineering Analysis Total
0-20 0-10 0-10
Fly Ash
Clay Mixed with Coke
Natural Clay
0
5
5
8
5
5
5
5
8
13
15
18
The emission factor developed for fly ash sintering is based on
the assumption that only half the reported losses (viz. 10% of input)
are actually airborne. This is an engineering judgment If all
the reported losses became airborne, the factor for fly ash would
be 240 Ib/ton instead of the 100 to 120 shown in Table 7.6-1.
-------
7-41
APPENDIX 7.6
Clay Sintering Emission Data
A. Data Obtained from Reference 2.
Sintered Material Natural Clay .
Input Rate 560 tons/day
Finished Product Rate 420 tons/day
Particulate Removed by Dust Collector 2 tons/day
Thus assuming the dust collector is only 80% efficient, the
sintering process dispels 2.5 tons of particulate per 420 tons of
finished product, or 12 Ib/ton of finished product. A variation
from about 10 to 14 Ibs/ton could be expected
B. Data Obtained from Reference 3.
Sintered Material 90% Clay, 10% Pulverized Coke
Input Rate 35 tons/hr
Finished Product Rate 26 tons/hr
Particulate in Exhaust Gas After Collector 0.74 lb/1000 Ib Exhaust Gas
Collector Type Cyclone
Quantity and Temperature of Exhaust Gas 94,200 cfm at 175°F
The above information yields particulate emissions as follows:
94,200 cfm at 175°F is equivalent to 78,600 scfm
or 4,720,000 scfh. This amount of gas weighs 355,000 Ib.
Thus 355,000 Ib gas x 0.74 Ib part = 263 Ib part/hr
hr 1000 Ib gas
Assuming the collection equipment (cyclone) has an efficiency
of 75%, the 263 Ib represents 25% of the total emission. Total emissions
therefore are 1050
-------
7-42
This amount of particulate represents 40 Ib/toh of finished
product (36 tons/hr^' An assumeci collection efficiency of 85%
would give a factor of 67.5 Ibs/ton while an,efficiency of 60%
would give 25 Ibs/ton.
Table 7.6-3 presents a summary of the emission data derived
from the above calculation and the data found in References 7 and 8.
Table 7.6-3. Particulate Emissions From Sintering Operations
Sintered Material, Particulate Emissions Reference Number
Operation, and Ib/ton of Finished Product
Qualifying Conditions
Based on estimate of par- 12 (10 to 14) 2
ticulate collected from
sintering of natural clay
in rotary kiln.
B#sed on material-balance 20 7 and 8
for sintering clay mixed
with limestone.
Based on stack sample after 40 (25 to 65) 3
collection equipment; 90% clay,
10% pulverized coke pellets
sintered on traveling grate,
updraft sintering machine.
The emissions reported in References 7 and 8 are not the result
of actual tests but of an engineering analysis. Further, the analysis is
based on clay-mixed-with-limestone. While the analyzed process
is unrelated to sintering of clay for the purposes of producing light-
weight aggregate, it is presented herein as a model to lend reliability
to figures based on scant data. That these emissions are between the
figure calculated in A and B, indicates the calculated emission factors
are in a t 50% range.
Crushing, screening and storage losses were estimated from the data
presented in Chapter 7-4 for rock crushing.
-------
7-43
REFERENCES 7.6
1. Anon. Sintering Profit from a Waste Disposal Problem.
Checmial Engineering. 71_:34, August 31, 1964.
2. Private Communication with a Clay Sintering Firm, October 2, 1969.
3. Private Communication with an Air Pollution Control Agency,
October 16, 1969. -
4. Duprey, R.L. Compilation of Air Pollutant Emission Factors.
National A1r Pollution Control Administration. Raleigh, North Carolina.
Public Health Service Publication 999-AP-42. 1968. p. 6 and 7.
5. Private Communication with a Fly Ash Sintering Firm, September 29, 1969,
6. Section 7.4, Supra.
7. Peters, F.A. et al. Methods for Producing Alumina From Clay, an
Evaluation of the Lime-Soda Sinter Process. Bureau of Mines,
Washington, D.C. Report of Investigation. 6927. 1967.
8. Henn, J.J. et al. Methods for Producing Alumina From Clay, An
Evaluation of Two Lime Sinter Processes. Bureau of Mines.
Washington, D.C. Report of Investigation 7299. September 1969.
GENERAL REFERENCES
Informative Air Pollution Problems in Fly Ash Sintering Plants,
. i-1"*"
T 1-5 Public Utilities Committee Report No. 6 J. Air Pollution
Control Association. 1_5:123-124, March 1965.
Wirt, R.L. and W.A. Rumberger. Eastern Sintering Plant Now
Producing Fly Ash Pellets. Rock Products Mining and Processing
6^:62-66, June 1964.
Con Ed Turns Waste to Wealth at Fly Ash Sintering Plant. Rock
Products. 68:81-82, October 1965.
Private Communication with the Consolidated Edison Company, New York.
September 1969.
-------
7-44
7.7 LIME MANUFACTURING
Process Description
Lime (CaO) is the high temperature product of the calcination
of limestone which is calcium carbonate (CaCOg). Lime is
manufactured in vertical or rotary kilns fired by coal, oil, or
natural gas. Figure 7.7-1 presents a schematic process ..diagram
of lime manufacturing. Kiln temperatures approaching 950°C
decompose the limestone with the loss of C02 by the following
reaction:
CaC03 -* CaO+C02
The charge to the kiln ranges in size from stones of 6-8 inches
diameter for the vertical kiln to 1/4 to 1/2 inch diameter for
the rotary kiln. Somewhat more than 50% of the Time produced
in the United States is from rotary kilns. Several modifications
of the vertical and rotary kilns have been introduced. However,
the standard vertical .and rotary kilns are, by far, the most
common types of lime manufacturing equipment. Typical exhaust
rates for vertical kilns, averaging approximately 3.5 tons per
hour, are 8000-10,000 SCFM. For rotary kilns, averaging 14-16
tons per hour, the exhaust rate is approximately 75,000-80,000
3
SCFM. Other types of kilns currently in use are fluidized bed,
modified vertical, and traveling grate kilns. Their typical
features are good fuel economy and lower emission rates. These
types are used for the minor portion of the production in the
United States.1
-------
P- Participates
NOX - NO, N02
SOX- S02, S03
P, NOX, SO,
Row
Material
Storage
Rotary Kiln
Stone
P,NOX1SO»
Feed
1
Fuel
Air
tn
CaO
Vertical Kiln
Figure 7.7-1. Llf^E MANUFACTURING
-------
7-46
Factors Affecting Emissions
Factors affecting emissions from lime manufacturing
kilns are: (1) the type and capacity of the kiln, (2) the type
of fuel used to fire the kiln, (3) the rate of air flow through
the kiln, (4) the particle size of the charge, (5) the amount
of agitation of the charge, and (6) the type and extent of
control equipment used to reduce the emissions from the kiln.
Emissions
Atmospheric emissions in the lime manufacturing industry
include the particulate emissions from the mining, handling,
crushing, screening and calcining of the limestone and the
combustion products from the kilns. The lime emitted from
the kilns (referred to as quicklime) is a fine particulate
which may be 15% of the total weight of limestone charged to
the rotary kiln. The vertical kilns, because of the use of
larger size of charge material, lower air velocities and less
agitation, have considerably less particulate emission. Emission
of fly ash and smoke may be a greater problem in the vertical
kilns which are fired by coal or heavy fuel oil. Control of
emissions from vertical kilns is accomplished by sealing the
exit of the kiln and exhausting the gases through various
control equipment or through other processes, i.e., alkali
and sugar industry where the C09 content of the exhaust is
1
utilized.
Particulate emission problems are much greater on the
rotary kilns due to a smaller size of charge material (1/2" -
1/4"), higher fuel consumption, and greater air velocities.
-------
7-47
through the rotary chamber. The rotary kilns are becoming
more popular for new installations due to their average 'il
capacity. Methods of control on rotary kiln plants include
simple and multiple cyclones, wet scrubbers, baghouses and
electrostatic precipitators. The most common control is the
cyclone. A cyclone's collection efficiency is approximately
2
70%, with better efficiency for particles greater than 10 microns.
Bag filtration and venturi scrubbers are often used to obtain
99% + collection efficiencies. Exit grain loadings of 0.05 to
4
0.6 have been measured after various scrubbing devices.
Typical analyses of the particulate emission from a
lime kiln showed lime (CaO) dust to constitute two thirds of the
material with CaC03 being the remainder. Products of fuel
combustion are also emitted. For coal these are primarily sulfur
oxides and fly ash. The amounts of these emissions are
inconsequential compared to the lime dust emission. Table 7.7-1
lists the particulate emissions from lime manufacture.
Table 7.7-1. Particulate Emissions from Lime Manufacturing
Operation Emissions, Ibs /ton processed - uncontrolled5
Crushing 7
primary 31 (2.4 to 78)
secondary 2 -
Calcining
vertical 8 (2.5 to 15.4)
rotary 315 (100 to 430)
a) Cyclones could reduce this factor by about 70%
Venturi scrubbers could reduce this factor by about'95-99%
Fabric filters could reduce this factor by about 99%.
-------
7-48
Reliability of Emission Factor
Emission factors from primary crushing, vertical and rotary
kilns are considered reliable, and no further work is indicated
in these areas at this time. Factors for secondary crushing are
questionable due to lack of data. These emissions do not appear
to be major. Thus it is felt no further work is necessary in
this area at this time. Table 7.7-2 presents the factor
ranking.
Table 7.7-2. Emission Factor Ranking for Lime Manufacturing
Engineering
Operation Emission Data Process Data Analysis Total
0-20 0-10 0-10
Crushing
primary
secondary
Kilns
vertical
rotary
10
5
10
7
5
2
8
8
5
2
5
5
20
9
23
20
-------
7-49
APPENDIX 7.7
Table 7.7-3. Particulate Emissions from Lime Manufacturing
Operation
LIMESTONE CRUSHING
Primary
Average
Secondary
LIME KILNS
Vertical
Average
Rotary
Emission, Ibs/ton processed
5.0
8.0
18.3
9.4
2.4
36.0
78.3
371. Oa
374. Oa
31.5
2.T
7.4
5.3
15.4
8.6
2.5
7.8
100-300
430
Reference
3
3
3
3
3
3
3
3
3
3
1
2
2
2
1
2
a) Not used in determining average.
-------
7-50
REFERENCES 7.7
1. Lewis, C., and B. Crocker. The Lime Industry's Problem of
Airborne Dust. J. of the Air Pollution Control Association.
19.:31-39, January 1969.
2. A Study of Lime Industry in the State of Missouri for the
Air Conservation Commission of the State of Missouri.
Resources Research, Inc. Reston, Virginia. December 1967.
54 p.
3. State of Maryland Emission Inventory Data. Maryland State
Department of Health. Baltimore, Md. 1969.
4. Taylor, C.E. Lime Kilns and Their Operation. In: Atmospheric
Emissions from Sulfate Pulping. Hendrickson, E.R. (ed.).
De Land, Florida. E.O. Painter Printing Co. April 28, 1966.
p. 244-250.
GENERAL REFERENCES
Kenline, P.A., and J.M. Hales. Air Pollution and the Kraft
Pulping Industry. Division of Air Pollution, Public Health
Service Publication 999-AP-4. November 1963. p. 5 and 10.
-------
7-51
Process Description
7.8 CONCRETE BATCHING
1,2
Concrete batching involves the proportioning of sand, gravel,
and cement by means of weight hoppers and conveyors into a mixing receiver
such as a transit mix truck. The required amount of water is also dis-
charged into the receiver along with the dry materials. In some cases *
the concrete is prepared for on-site building construction work or the
manufacture of concrete products such as pipe and prefabricated construc-
tion parts. Particulate emissions consist primarily of cement dust,
but some sand and aggregate gravel dust emissions do occur during
patching operations. There is also a potential for dust emissions during
the unloading and conveying of concrete and aggregates at these plants
and during the loading of dry batched concrete mix. Another source of
dust emissions is the traffic of heavy equipment over unpaved or dusty
surfaces in and around the concrete batching plant.
Factors Affecting Emissions
Factors affecting emissions include the amount and particle size
of materials handled and the type of handling methods used. Enclosure
of dumping and loading areas, and of conveyors and elevators, filters
on storage bin vents and liberal use of water sprays will reduce particu-
late emissions. The degree to which dust control of traveled surfaces,
and general plant housekeeping is practiced will also affect emissions.
Emissions
Very limited particulate emissions data were found in the literature.
These data estimated emissions at 0.04 to 0.05 Ibs of dust per ton of
o
concrete. This is equivalent to 0.08 to 0.1 Ibs of dust per cubic yard
while using good dust control procedures. Emissions of 0.2 Ibs/cubic
*
yard could probably be expected for some dusty operations.
o
* 1 yard of concrete = 4000 pounds
-------
7-52
Reliability of Emission Factors
No actual source test data are available. Engineering estimates were
the only references to emissions. Data and references to emissions are old and
based on engineering estimates. Further work must include source test information.
Lack of new work in the field causes this factor to be questionable. Table 7.8
presents the factor ranking.
TABLE 7.8-1 Ranking of Emission Factors
Emission Data Process Data Engineering Analysis Total
0-40 0-10 0-10
12
No appendix is included in this section due to a lack of data.
-------
7-53
REFERENCES 7.8
Vincent, E.J. and J.L. McGinnity. Concrete Batching Plants, In:
Air Pollution Engineering Manual, Danielson, J.A. National Air
Pollution Control Administration. Raleigh, North Carolina,
Public Health Service Publication 999-AP-40, 1967. p. 334-335.
Personal Communication, The National Ready Mixed Concrete
Association, September 1969.
.Allen, G.L., F.H. Viets, L.C. McCabe. Control of Metallurgical
and Mineral Dust and Fumes in Los Angeles County, California.
U.S. Bureau of Mines, Department of the Interior I.C. 7627,
1952. p. 60.
GENERAL REFERENCES
Gaskin, H.L. Modern Batch Plant Technology, presented at the
37th Annual Convention of the National Ready Mixed Concrete
Association, Los Angeles, California. 1967.
Child, G.B. A Modern High Capacity Batching Plant. Presented
at the 35th Annual Convention of the NRMCA, Miami, Florida, 1965.
Gottheil, L.A. An Automatic Ready Mixed Concrete Plant with
Capacity of 300 Cubic Yards per Hour. Presented at the 31st
Annual Convention of the NRMCA. Miami, .Florida. 1961.
Concrete Plant Standards of the Concrete Plant Manufactures Bureau,
3rd Revision, 1967. NRMCA.
-------
7-54
7.9 FIBER GLASS MANUFACTURING
Process Description
Fiber glass is manufactured by melting various raw materials to form
glass, drawing the molten glass into fibers, and coating the fibers with an
organic material. Figure 7.9.1 is a simplified flow diagram of the fiber glass
manufacturing process. The basic ingredients for continuous-filament glass
fiber are:
Silicon dioxide 52 - 56%
Calcium oxide 16 - 25%
Aluminum oxide 12-16%
Boron oxide 8-13%
Sodium and Potassium oxides ,0-1%
Magnesium oxide 0-6%
The glass-forming reaction takes place at 2800°F (about 100°F higher
than that required for normal plate glass) in a large rectangular, gas-or-oil-
fired reverberatory furnace. The melting furnaces are equipped with either
regenerative or recuperative heat recovery systems.
After refining, the molten glass passes to a forehearth where
temperatures are kept between 2,300 and 2,400°F. At this point, the glass is
either formed into marbles for subsequent remelting, or passed directly through
orifices (bushings) to form a filament. The older method of producing continuous
filament fiber glass is to form the molten glass into marbles, inspect the
marbles for quality, and then remelt them for final filament drawing. This
method is still required for very fine fibers (less than 0.00025 inch diameter).
-------
l-3lbs./TON
RAW
MATERIALS-
FUEL
20-100 Ibs./TON
3-IOlbs./TON
BINDER
GLASS
MELTING
FURNACE
1
MOI TFN
GLASS
\
V
1
CURING
OVEN
FORMING
LINE
1
PRODUCT
FUEL
I
I
tn
en
Figure 7.9-1. Fiber glass manufacturing process
-------
7-56
However, for larger fibers, the marble producing stage may be bypassed and
the glass filaments drawn directly from the forehearth through orifices in
platinum-rhodium bushings.
After forming, the continuous filaments are treated with organic
binder material, wound, spooled, and sent to a high-humidity curing area where
the binder sets. Retention time in the curing area varies from 1 to 10 hours
and depends on the type of binder used and the desired product. The product is
then cooled by blowing air over it.
In the manufacture of glass wool as used in insulation, the molten
borosilicate glass is also drawn through orifices. However, in this case,
the filament is dropped onto a moving bed conveyor or forming line and sprayed
with a binder. This stringy mass is then cured by heat treating at temperatures
234
in the 300 - 600°F range in a curing oven. ' * Phenolic base organic binders
have been used in this operation.
The major emissions from fiber glass manufacturing processes are
particulates from the glass melting furnace, the forming line, the curing
oven, and the product cooling line. In addition, gaseous organic emissions occur
from the forming line and curing oven. Combustion products from the natural
gas or oil burned in the melting furnace and curing oven are also emitted. The
emissions from the forming line are the largest single source of emissions and
are characterized by a dense light-colored cloud.
o
Factors Affecting Emissions
Particulate emissions from the glass melting furnace are affected by
basic furnace design, type of fuel (oil or gas), raw material size and composition,
5
and type and volume of furnace heat recovery system. Regenerative heat recovery
systems generally allow more particulate matter to escape than do recuperative
systems. Particulate control systems are not generally used on the glass furnace.
-------
7-57
Organic and'particulate emissions from the forming line are
most-affected by the composition and quantity of the binder, and the
spraying techniques used to coat the fibers. Very fine spray and
volatile binders increase emissions. Pollutant control systems are
not generally used.
Emissions from the curing oven are affected by the oven
temperature and binder composition. Direct-fired afterburners with
heat exchangers may be used to control emissions.
Emissions
Particulate emissions from fiber glass manufacturing based on
data in the Appendix are summarized in Table 7.9-1.
Table 7.9-1. Uncontrolled Particulate Emissions From Fiber Glass Manufacturing
Process
Glass Furnace3
Regenerative Heat Exchanger
Recuperative Heat Exchanger
Electric Induction Furnace
Forming Line
Curing Oven
TOTAL
Emissions, Ibs/ton of material
processed
3 (2 to 4)
--1 (0.5 to 1)
0
50 (20 to 100)
7 (3 to 10)
57 to 60 (25-114)
a) Only one type is usually used at any one plant.
Overall emissions may be reduced approximately 50% by using:
1) An afterburner on the curing oven.
2) A filtration system on the product cooling and handling processes.
3) Process modifications for the forming line.
-------
7-58
Hydrocarbon emission data were not available and due to the
extreme variability of these emissions depending on binder composition
and operating temperatures, no reliable estimate could be made.
Reliability of Emission Factors
The forming line emissions account for the major portion of the
plant emissions. However, quantitative emission data from this process
were limited to one stack test. Due to this lack of emission data
and the variability in emissions due to process variables, the overall!
factor is questionable. Table 7.9-2 presents the factor ranking.
Table 7.9-2. Emission Factor Ranking for Fiber Glass Manufacturing
Emission Data Process Data Engineering Analysis Total
0-20 ' 0-10 0-10
6 2 5 13
-------
7-59
APPENDIX 7.9
Table 7.9-3. Participate Emissions From Fiber Glass Manufacturing
Operational Source Uncontrolled Emissions, Reference
Ib/ton of Product
1. Glass Melting Furnace 3.4 7
(Regenerative)
2.0-4. 8
3. 9
1.0-2 6
Glass Melting (Recuperative) 0.5-1. 6
2. Forming Line 23.5 4
100. 6
3. Curing Oven 3.4, 14 4
3.6, 6.4 4
10. 4
(Curing Mineral Wool) 4. 3
-------
7-60
REFERENCES 7.9
1. Chopey, N.P. New Plant Features Latest Look in Making
Glass Fibers. Chemical Engineering. 68^:136, May 15, 1961.
2. Shreve, R.N. Chemical Process Industries. (3rd Edition).
New York. McGraw-Hill Book Company, 1967. p. 700-702.
3. Spinks, J.L. Mechanical Equipment. In: Air Pollution
Engineering Manual, Danielson, J.A. (ed.). National Air
Pollution Control Administration, Raleigh, N.C. Public
Health Service Publication 999-AP-40. 1967. p. 342.
4. Private Communication with the New Jersey State Dept. of
Health. July 1969.
5. Netzley, A.B., and J.L. McGinnity. Chemical Processing
Equipment. In: Air Pollution Engineering Manual, Danielson, J.A.
(edO. National Air Pollution Control Administration,
Raleigh, N.C. Public Health Service Publication 999-AP-40.
1967. p. 724-733.
6. Private Communication with Fiber Glass Company, October 1969.
7. Chass, R.L., et al. Total Air Pollution Emissions In Los
Angeles County. J. of the Air Pollution Control Association.
1i(5):351-366, October 1960.
8. Kansas City Air Pollution Abatement Activity. National Air
Pollution Control Administration. Raleigh, N.C. January 1967.
p. 53.
9. Larson, G.P., et al. Evaluating Sources of Air Pollution.
Industrial and Engineering Chemistry. 45(5) :1070-1074, May 1953.
-------
7-61
7.10 PULPBOARD MANUFACTURING
General Information
Pulpboard manufacturing includes the manufacture of
fibrous boards from a pulp slurry. This encompasses two
distinct types of product, paperboard and fiberboard.
Paperboard is a general term which describes a sheet
0.012 inches or more in thickness made of fibrous material on
a paper machine. It is commonly made from wood pulp, straw,
or paper stock. In short, paperboard is merely heavy paper,
manufactured on a cylinder machine or a Fourdrineir machine
in the same manner as paper less than 0.012 inches thick.
Fiberboard, also referred to as particle board, is much
thicker than paperboard and is made somewhat differently.
This general product is used extensively by the construction
industry and includes both cellular fiber and hard pressed
composition board (containing no gypsum). Resins are often
used in fiberboard to impart the characteristics of strength
and stability.
Process Description
There are two distinct phases in the conversion of wood
to pulpboard. These are (!) the manufacture of pulp from
the raw wood and (2) the manufacture of pulpboard from the
pulp. This investigation concerns itself only with the latter
2
phase, the former having been the subject of earlier reviews.
-------
7-62
Paper-board is manufactured on a cylinder machine or a
Fourdrineir machine. Whether the board is formed on a cylinder
machine or a Fourdrineir machine does not appreciably affect
emissions since each machine utilizes the same principle. For
the purposes of this report, the Fourdrineir machine will be
discussed.
First the stock is sent through screens into the head
box from which it flows through the sluice onto a moving
bronze-wire screen. Approximately 15% of the water is removed
by suction boxes located under the screen. From the wire
screen, the paperboard is transferred to the first felt blanket
and enters the drying section of the machine with a moisture
content of 60 to 70 percent. The drying section is vented and
consists of steam-heated drying rolls and felt-drying blankets.
Water content of the board upon leaving the dryer is between
6 and 10, percent. After drying, the board enters the calender
stack which imparts the final surface to the product.
Unlike paperboard, fiberboard is often made from fibrous
by-pmduc;ts such as bagasse. After pulping, the slurry is pumped
to a shredder and washed in rotary washers to remove dirt,
pith, and soluble compounds. The slurry next enters half
stock chests where the sizing is added.
A typical fiberboard composition is:
100 Ibs. shredded fiber
3 Ibs. sawdust
1 - 2 Ibs. wax, resins, or other binders
150 Ibs. water
Trace - al urn
Trace - aluminate
-------
7-63
The entire mass is then agitated and the fibers refined in a
Jordan engine to give optimum fiber size. The refined fiber
is transferred to stock chests, from which it is fed to the
head box of the board machine. The stock is fed onto forming
screens and led to drying felts and press rolls. To obtain the
required thickness, individual layers are felted together. The
board is then dried at 300 to 450°F in a drying tunnel up to
1000 feet long. After drying, the product is cut and fabricated.
Emissions
The second phase of the paperboard making process does
not contribute to air pollution. Emissions from the paper-
making machine consist only of water vapor. ' ' The dryer
section exhausts approximately 430,000 SCF of air per ton of
finished prqduct. This air contains between 2,000 and 2,700 Ib.
of water vapor. TaBVe'"7:10-1 .presents emission data. -
Table 7.10-1. Emission Factors for Pulpboard Manufacturing
'".Product
Total Vol.
SCF/ton
Water Vapor
Ib/ton of
finished product
Parti cul ate
Ib/ton of
finished product
Sulfur
Ib/ton of
finished product
Paperboard0 430,000
Fiberboard
2,700
-0-
0.6
-0-
Average particulate emission from the drying operation at
a fiberboard operation are approximately 0.6 Ib/ton with about
75% of the particulate by weight less than 44 microns. Additional
particulate emissions also occur from the cutting and sending
operations. However, no quantitative data were available from this
portion of the operation. These emissions can be easily controlled
by cyclone and fabric filter control systems.
-------
7-64
Reliability of Emission Factor.
Emissions from the drying operations of paperboard
manufacturing do not appear to be a major problem, and the
factors reported in this review are believed to be good.
Additional work is,however,required to obtain emission data
from the product trimming, cutting, and other finishing operations.
The reported factor for particulate emissions from
fiberboard drying is also believed to be accurate. However,
in addition to determining emissions from the cutting and
fabricating operations, additional work is warranted to
determine the gaseous emissions from the dryer due to the
various resins and binders used in the stock. Emission factor
rankings are presented in Table 7.10-2.
Table 7.JO-2. Emission Factor Ranking for Pulpboard Manufacture
Emission Data Process Data Engineering Analysis Total
0-20 0-10 0-10
Paperboard 10 8 8 26
Fiberboard 5 8 3 16
One major assumption was made in obtaining the factors
presented in this section in that the particle emissions from
the'drying of fiberboard are assumed to be identical for all
fiberboards regardless of the type of pulp and binder used.
-------
7-65
REFERENCES 7.10
1. The Dictionary of Paper. American Paper and Pulp Association.
New York. 1940.
2. Duprey, R.L. Compilation of Air Pollutant Emission Factors.
National Air Pollution Control Administration. Raleigh, N.C.
Public Health Service Publication 999-AP-42. 1968. p. 43.
3. Pollution Control Progress. J. Air Pollution Control
Association. 1_7:410, June 1967.
4. Private Communication. Dr. I. Gellman, Technical Director,
National Council of the Paper Industry for Clean Air and
Stream Improvement. New York. October 28, 1969.
5. Hough, G.W., and L.J. Gross. Air Emission Control in a
Modern Pulp and Paper Mill. American Paper Industry.
51:36, February 1969.
6. Private Communication. New Jersey State Department of
Health, July 1969.
-------
8. ORGANIC SOLVENTS
Organic solvent emissions from dry cleaning and surface
coating operations are presented in this section. The solvent
emissions from these processes represent a wide range of hydrocarbon
compounds. Some dry cleaning plants recover the solvent which
evaporates during operations when a substantial savings in
operating costs can be effected. Nearly all solvents from
surface coating operations escape to the atmosphere. Control
techniques such as adsorption or incineration are used to reduce
the emissions of organic compounds.
-------
8-2
8.1 DRY CLEANING
Process Description
Clothing and other textiles may be cleaned by treating them
with organic solvents. This treatment process involves agitating the
clothing in a solvent bath, rinsing with clean solvent, and drying
with warm air.
There are basically two types of dry cleaning installations:
those using petroleum solvents (Stoddard and 140°F), and those using.
chlorinated synthetic solvents (perchloroethylene). All of the older
dry cleaning plants used petroleum solvents. Because of the inherent
fire hazard, most zoning restrictions prohibit the operation of
petroleum cleaning plants in residential and commercial areas. This
led to the development of non-flammable, chlorinated solvents which
can be used in residential installations.
In a petroleum solvent dry cleaning plant, the equipment generally
consists of a washer, centrifuge (extractor), tumbler, filter, and
often a batch still. The centrifuge is used to recover solvent by
spinning it; from the clothes. The clothes then enter a tumbler where
they are dried with warm air. The tumbler is usually vented through
a lint trap to the atmosphere in this type of plant.
In synthetic solvent plants, the washer and extractor are a
single unit. The tumbler is vented through a closed system with a
condenser for vapor recovery while in operation. The tumbler is
vented to the atmosphere only during short deodorizing periods.
Both adsorption and condensation systems may be used to control
hydrocarbon emissions from dry cleaning plants. Solvent recovery
systems are not only commercially available as part of a synthetic
solvent cleaning plant, but they are also economically attractive.
The primary control element is a water cooled condenser which is an
integral part of the closed cycle in the tumbler or drying system.
Up to 95% of the solvent that is evaporated from the clothing is
-------
8-3
recovered here. About half of the remaining solvent is then recovered
in an activated-carbon adsorber giving an overall control efficiency
of 97-98%. About half of the synthetic dry cleaning plants in the
country use carbon adsorbers.
There are no commercially available control units for solvent
recovery in petroleum based plants because it is less economical to
recover the vapors. The vaporized solvent is not condensable at the
temperatures employed and thus the whole solvent recovery burden
would fall on an adsorption system, necessitating equipment up to 20
times larger than that used in a comparable synthetic solvent .plant.
Factors Affecting Emission's
Factors affecting hydrocarbon emissions from dry cleaning operations
include the amount of solvent :used, the amount of fabric cleaned,
the temperature of the wash, the degree of enclosure of the washers,
the maintenance of the washers, the amount of ventilation throughout
the operation, the amount of open handling of wet fabric, the aromatic
content of the solvent, the degree to which control equipment is
applied to the exhaust system of the plant and the amount of the
generated solvent reaching the control equipment.
Emissions
The major source of hydrocarbon emissions in dry cleaning is the
tumbler through which hot air is circulated to dry the clothes.
Drying leads to vaporization of the solvent and emissions to the
atmosphere unless control equipment is used. Because of the volatility
of the solvents used, additional emissions occur when storage tanks
are loaded, equipment doors are opened, ductwork or equipment leaks
and textiles soaked in solvent are removed from equipment.
These latter sources are more of a problem in petroleum plants because
the low cost of the solvent does not give much economic incentive
for conserving the solvent during handling operations.
-------
8-4
Since dry cleaning is only a physical process, hydrocarbon
emissions consist of the respective evaporated solvents. Chemical
composition of petroleum solvents was about 46% paraffins, 42%
naphthenes, and 12% aromatic compounds. The advent of Los Angeles
Rule 66 has led to some reformulations so that in many parts of the
country the solvent's aromatic content now is at or below 8 percent.
Table '8.1-1 presents the emissions from dry cleaning operations
based on data in the Appendix.
The tnend in dry cleaning operations today is toward the smaller
package operations located in shopping centers and suburban business
districts. These operations typically handle less than 2,000 Ibs.
of clothes per week with 1500 Ibs. being an average weekly production..
These plants almost exclusively use perchloroethylene and have recovery
systems for -the solvent built into the process. It has been estimated
that perchtteroethylene is used on 50% of the weight of clothes dry
cleaned in ihe United States today and that 70% of the dry cleaning
3
plants use ^perchloroethylene. The remaining plants use the common
petroleum solvents but in cases where air pollution potential is
high, i.e., Los Angeles, regulations are requiring the use of petroleum
solvents Adi-h ~a low initial concentration of aromatics.
Table 8.1-1 Total Hydrocarbon Emissions from Dry Cleaning Operations,
Ibs/ ton clothes cleaned9
Petroleum Solvents Chlorinated Solvents
Uncontrolled 305 Ibs (22.7 gal) 210 Ibs (15.6 gal)
Range 125 Ibs to Range 70 to 280 Ibs
500 Ibs '
Average Control - 95
Good Control - 35
Approximately il8-25 Ibs of clothes are cleaned per person per year.
Reliability of Emission Factor
Little emission data on source tests at dry cleaning plants are
available.. Most emission calculations are based on solvent usage and
-------
8-5
throughput at the plants. For air pollution calculations virtually
all solvent loss was considered as loss to the atmosphere. Due to
good evaluation of conditions at dry cleaning operations and reliable
estimates of solvent usage, the factor is considered good. Table
8.1-2 shows the factor ranking.
Table 8.1-2 Emission Factor Ranking
Emission Data Process Data Engineering Analysis Total
0-20 0-10 0-10
58 8 21
-------
8-6
APPENDIX 8.1
Emission Data
Lbs Hydrocarbon Solvent Released/Ton Clothes Cleaned
Uncontrolled
After Control with Activated-Carbon Adsorber
Perchl oroethyl ene
270
230
481
128-
7Q,
280
Reference
1
5
5
6
3
3
95
New Plant
30-40
Reference
T
7/
Data in Reference 1 are 10 gallons emitted per 1000 Ibs clothes
for uncontrolled, 3.5 gallons per 1000 Ib for controlled plants.
Density of perchloroethylene is about 13.5 Ibs/gallon (s.g. = 1.623).
Average quantity of clothes cleaned is about 18 Ibs/capita/year
o t
in moderate climates and about 2.5 Ibs/capita/year in colder areas.
An average emission factor on a per capita basis may be estimated
as follows. Since 50% of all plants use petroleum solvents,
4
25% of synthetic solvent plants are controlled:
and
r
[
305 Ibs
ton clothes
18 Ibs/capita/year
x 2000 Ibs/ ton
controlled factor 18
n
°-
r?1Q
L21°
18
000
0>25] = 2 Ibs/cap1ta/year in,
moderate climaies, and,
by a similar calculation,
using 25 Ibs/capita,
2.7 Ibs/capita/year in
colder areas.,
-------
8-7
REFERENCES 8.1
1. Chass, R. L., C. V. Kanter, and 0. H. Elliot. Contribution of
Solvents to Air Pollution and Methods for Controlling Their
Emissions. J. Air Pollution Control Association, 13:64-72.
February, 1963.
2. Bailor, W.C.y Dry"Cleaning Equipment, In: Air Pollution Engineering
Manual, J.A. Danielson, (ed.) National Air Pollution Control
Administration, Raleigh* N.C., Public Health Service 999-AP-40, p. 393-
397, 1967.
3. Personal Communication, The National Institute of Dry Cleaning, 1969.
4. Personal Communication, S. Landon,.Washer Machinery Corp., June, 1968.
5. Dry Cleaning Plant Survey, Kent County, Michigan, 1965, Michigan
Dept. of Public Health. .
6. Bi-State Study of Air Pollution in the Chicago Metropolitan Area,
1957-1959.
7. Personal Communication, A. Netzley, Los Angeles County Air Pollution
Control District, July, 1968.
8. Los Angeles and San Francisco Area Data as reported In: Compilation
of Air Pollutant Emission Factors, Duprey, R.L., National Air
Pollution Control Administration, Public Health Service Publication
999-AP-42, p. 46.
-------
8-8
8.2 SURFACE COATING
i 9
Process Description '
Surface coating operations are primarily involved with the
application of paint, varnish, lacquer, or paint primer for decorative
or protective purposes. This is accomplished by brushing, rolling,
spraying, flow coating and dipping. Electro-dipping is also used.
Spraying is generally carried out in booths. Other coating techniques
such as dip tanks, flow coaters, and roller coaters are often operated
without hooding or ventilation. Hooding is used on most operations
where some ventilation is required.
Control of the gaseous emissions can be accomplished by the use
of adsorbers (activated carbon) or by afterburners. The collection
efficiency of activated carbon has been reported at 90% or greater.
Water curtains or filter pads have little or no effect on escaping
solvent vapors. These are widely used, however, to stop paint
particulate emissions.
Factors Affecting Emissions
The 'major factor affecting emissions from surface coating
operations is the amount of volatile matter contained in the coating.
The type of operation (spraying, dipping, rolling, etc.) and the extent
to which control equipment is used will also affect emissions for
those applications which occur in an enclosed area.
Emissions of hydrocarbons occur due to the evaporation of the
paint vehicles, thinners, and solvents used to facilitate the application
of the coatings. This evaporation is very rapid in high pressure
spraying Mvere -as much as 80% of the spray does not contact the part
to be coated and is called overspray. In brush and roller applications
the evaporation occurs more slowly and the total evaporation time
depends on the coating thickness.
-------
8-9.
The volatile portion of.most common surface coatings averages
approximately 50% and most, if not all, of this is emitted upon applying
and drying of the coating. The compounds released include aliphatic
and aromatic hydrocarbons, alcohols, ketones, esters, alkyl and aryl
hydrocarbon solvents and mineral spirits. Table 8.2-1 presents
emission factors for surface coatings.
Table 8.2-1 Gaseous Emissions from Surface Coating Applications
Coating Type Emission, lbs/tona
Paint 1120
Varnish and Shellac 1000
Lacquer 1540
Enamel 840
Primer (Zinc Chromate) 1320
aReported as undefined hydrocarbons, usually organic solvents both
aryl and alkyl. Paints weigh 10-15 pounds per gallon, varnishes
weigh about 7 pounds per gallon.
The emission factor is based on the composition of the coating
and assumes that all of the solvent eventually evaporates from the
applied coating.
Reliability of Emission Factor
While no total emission data are available, solvent content
does provide a fairly accurate estimate of total organic emissions.
The ranking in Table 8.2-1 indicates these factors are reliable.
Table 8.2-2 Emission Factor Ranking for Surface Coating
Emission Data Process Data Engineering Analysis Total
0-20 Q-10 Q-10
59 9 23
-------
8-10
APPENDIX 8.2
Emission Data from the Literature
Coating
Paint
Varnish
Lacquer
Enamel
Primer
Composition
% Volatile
56
50
77
42
66
Emission Factor
Ibs/ton of coating
applied
1120
1000
1540
840
1320
Reported as undefined hydrocarbons, usually organic solvents
both aryl and alkyl.
-------
8-11
REFERENCES 8.2
1. Weiss, S.F., Surface Coating Operations, In: Air Pollution Engineering
Manual, Danielson, J.A. (ed.), National Air Pollution Control
Administration, Raleigh, N.C., Public Health Service Publication
999 AP-40, p. 387-390.
2. Control Techniques for Hydrocarbon Air Pollutants, National Air
Pollution Control Administration, Raleigh, N.C., First Draft,
Oct., 1969, Chap. 7.6.
GENERAL REFERENCES
Lunche, R.6., et. al., Emissions from Organic Solvent Usage in Los
Angeles County, 0. APCA 7^(4): 275-283, Dec., 1957.
Martens, C.R., Technology of Paints, Varnishes and Lacquers,
Rheinhold Book Corp., New York, N.Y., 1968.
Elliot, J. H., et. al., Experimental Program for the Control of
Organic Emissions for Protective Coating Operations, Los Angeles Air
Pollution Control District, June, 1962.
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