EPA-450/2-77-01^/
CONTROL TECHNIQUES
FOR LEAD AIR EMISSIONS
VOLUME I:
CHAPTERS 1 - 3
UNITED STATES ENVIRONMENTAL PROTECTION AGENCY
Office of Air Quality Planning and Standards
Emission Standards and Engineering Division
Research Triangle Park, North Carolina 27711
Telephone: (919) 541-5271
December 1977
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EPA-450/2-77-012
CONTROL TECHNIQUES
FOR LEAD AIR EMISSIONS
VOLUME I:
CHAPTERS 1 - 3
U.S. ENVIRONMENTAL PROTECTION AGENCY
Office of Air and Waste Management
Office of Air Quality Planning and Standards
Research Triangle Park, North Carolina 27711
December 1977
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NATIONAL AIR POLLUTION CONTROL TECHNIQUES ADVISORY COMMITTEE
Chairman and Executive Secretary
Mr. Don R. Goodwin, Director
Emission Standards and Engineering Division
Office of Air Quality Planning and Standards
U.S. Environmental Protection Agency
Research Triangle Park, North Carolina 27711
Committee Members
Dr. Lucile F. Adamson
1344 Ingraham Street, N.W.
Washington, D.C. 20011
(Howard University-Professor,
School of Human Ecology)
Mr. O.B. Burns, Jr., Director
Corporate Environmental Activities
Westvaco Corporation
Westvaco Building, 299 Park Ave.
New York, New York 10017
Mr. Donald C. Francois, Asst. Dir.
Div. of Natural Resources Management
Dept. of Conservation and Cultural
Affairs
P.O. Box 578
St. Thomas, Virgin Islands 00801
Dr. Waldron H. Giles, Manager
Advanced Material and Space
Systems Engineering
General Electric Company
Re-entry and Environmental Systems Div.
3198 Chestnut St., Room 6839B
Philadelphia, Pennsylvania 19101
Mr. James K. Hambright, Dir.
Dept. of Environmental Resources
Bureau of Air Quality and Noise
Control
P.O. Box 2063
Harrisburg, Pennsylvania 17120
Mr. W.C. Holbrook, Manager
Environmental and Energy Affairs
B.F. Goodrich Chemical Co.
6100 Oak Tree Blvd.
Cleveland, Ohio 44131
Mr. Lee E. Jager, Chief
Air Pollution Control Div.
Michigan Dept. of Natural Resources
Stevens T. Mason Bldg. (8th floor)
Lansing, Michigan 48926
Dr. Joseph T. Ling, Vice Pres.
Environmental Engineering and
Pollution Control
3M Company
Minnesota Mining and Manufacturing Co,
Box 33331, Bldg. 42-5W
St. Paul, Minnesota 55133
Mr. Marcus R. McCraven
Asst. Vice Pres. of Environmental
Engineering
United Illuminating Co.
80 Temple St.
New Haven, Connecticut 06506
Mrs. Patricia F. McGuire
161 White Oak Dr.
Pittsburgh, Pennsylvania 15237
(Member of the Allegheny Co. Board
of Health, Pennsylvania)
Dr. William J. Moroz
Prof, of Mechanical Engineering
Center for Air Environment Studies
226 Chemical Engineering, Bldg. II
Pennsylvania State University
University Park, Pennsylvania 16802
Mr. Hugh Mullen, Director of
Government and Industry Relations
I.U. Conversion Systems, Inc.
3624 Market St.
Philadelphia, Pennsylvania 19104
111
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Mr. C. William Simmons
Air Pollution Control Officer
San Diego Air Pollution Control
District
9150 Cheasapeake Dr.
San Diego, California 92123
Mr. E. Bill Stewart, Dept. Dir.
Control and Prevention
Texas Air Control Board
8520 Shoal Creek Blvd.
Austin, Texas 78758
Mr. Victor H. Sussman, Dir.
Stationary Source Environmental
Control Office
Ford Motor Co.
Parklane Towers West, Suite 628
P.O. Box 54
Dearborn, Michigan 48126
IV
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TABLE OF CONTENTS
Page
SUMMARY xix
1.0 INTRODUCTION 1-1
2.0 BACKGROUND INFORMATION 2-1
2.1 Definitions 2-1
2.2 Origin and Use of Lead 2-4
2.3 Types of Lead Emissions 2-5
2.4 Sampling and Analytical Methods 2-9
2.5 Sources of Lead Emissions 2-10
2.6 Control Devices 2-12
2.7 Fugitive Lead Emissions 2-34
2.8 Control Costs 2-36
2.9 Emission Estimates and Emission Factors 2-42
2.10 Emission Trends and Projections 2-44
2.11 Anticipated Impacts 2-52
2.12 Emergency Episode Procedures 2-58
2.13 References 2-59
3.0 COMBUSTION SOURCES 3-1
3.1 Leaded Gasoline 3-1
3.2 Coal, Oil, Waste Oil, and Solid Waste 3-76
VI
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TABLE OP CONTENTS (continued).
Page
4.0 INDUSTRIAL PROCESS SOURCES 4-1
4.1 Lead Alkyl Manufacture 4-1
4.2 Storage Battery Manufacture 4-23
4.3 Primary Nonferrous Metals Production 4-38
4.4 Secondary Nonferrous Metals and Alloy 4-131
Production
4.5 Ferrous Metals and Alloy Production 4-173
4.6 Lead Oxides and Pigments 4-278
4.7 Pesticides 4-291
4.8 Lead Handling Operations 4-292
4.9 Miscellaneous Sources of Lead
APPENDIX A A-l
APPENDIX B B-l
VII
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LIST OF FIGURES
Page
2-1 Approximate Flow of Lead Through 2-8
U. S. Industry in 1975
2-2 Map of the Major Lead Emission Sources 2-13
2-3 Criteria for Selection of Gas Cleaning Devices 2-19
2-4 Fabric Filter with Mechanical Shaker 2-21
2-5 Envelope Type Fabric Filter with Automatic 2-21
Reverse-Air Cleaning Mechanism
2-6 Reverse-Jet Fabric Filter 2-22
2-7 Orifice Scrubber 2-26
2-8 Orifice Scrubber 2-27
2-9 Mechanical Scrubber 2-27
2-10 Mechanical-Centrifugal Scrubber 2-28
2-11 Centrifugal-Impingement Scrubber 2-31
2-12 Venturi Scrubber Design and Operation 2-32
2-13 Major Design Features of a Common ESP 2-35
2-14 Factors Influencing Capital and Annual Costs 2-39
of Operating Air Pollution Control System
3-1 Octane Number Versus Lead Content for Gasolines 3-9
3-2 Yearly Trends of United States Passenger Car 3-14
Engine Design and Gasoline Quality
3-3 Historical Source of Octane Quality Commercial 3-15
Gasolines
3-4 Percent of Model Year Cars and of all Cars on 3-17
the Road for Which Premium Gasoline is
Recommended, and Percent Premium Sales,
1965-1976
3-5 United States Gasoline Demand - 1960-1975 3-18
3-6 Vapor Pressure of Lead Compounds 3-32
Vlll
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LIST OF FIGURES (continued)
Page
3-7 Predicted Reduction in Lead Use in Gasoline 3-40
From Estimated 1974 Level Based on Federal Fuel
Additive Regulations and Gasoline Use Increases
of 0 and 5 Percent Per Year
3-8 Projected Lead Reduction from 1974 Level 3-42
Resulting From the Use of Nonleaded Fuel in
1975 and Later Model Year Automobiles. Curves
C-D are for Resumption of Use of Leaded Fuel at
1974 Concentration for all 1980 and Later Model
Years
3-9 DuPont Muffler Lead Trap 3-48
3-10 Ethyl Corporation Tangential Anchored Vortex 3-50
Traps Construction Features
3-11 PPG Particulate Lead Trapping System Features 3-52
3-12 Spreader and Vibrating Grate Stokers 3-78
3-13 Pulverized-Coal Unit 3-79
3-14 Diagram of Coal-Fired Boiler Equipped with 3-86
an ESP
3-15 Total Capital and Annualized Costs for ESP's 3-89
on Coal-Fired Boilers
3-16 An Oil Front-Fired Power Plant Steam Generator 3-93
3-17 ESP Installation of a Municipal Incinerator 3-99
Showing Gas Conditioning System
3-18 Capital Costs for Various Types of Control 3-109
Devices for Municipal Incinerators
3-19 Annualized Costs for Various Control Devices 3-110
on Municipal Incinerators
4-1 Sodium-Lead Alloy Process for the Production 4-3
of Tetraethyl Lead
4-2 Typical Lead Reverberatory Furnace Used 4-7
in Lead Additive Manufacturing
IX
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LIST OF FIGURES (continued)
4-3 Electrolytic Process for Tetramethyl Lead 4-12
Production
4-4 Flow Diagram of Lead Acid Battery Plant 4-24
4-5 Average Controlled Lead Emissions From Tested 4-33
Facilities
4-6 A Typical Ore Mining and Processing Operation 4-41
4-7 Flow Diagram of Primary Lead Smelter 4-45
4-8 Lead Updraft Sintering Machine 4-46
4-9 Lead Blast Furnace 4-49
4-10 Process Flow Diagram For Primary Lead Smelting 4-57
Showing Potential Industrial Process Fugitive
Particulate Emission Points
4-11 Sulfuric Acid Plant Installed on a Primary 4-60
Lead Smelter
4-12 Flow Diagram of Primary Zinc Production 4-73
4-13 Dowmdraft Sinter Machine 4-76
4-14 Horizontal Retort 4-76
4-15 Vertical Retort 4-80
4-16 Process Flow Diagram For Primary Zinc 4-84
Production Showing Potential Industrial
Process Fugitive Emission Points
4-17 Primary Copper Smelter Flow Diagram 4-96
4-18 Multiple-Hearth Roaster 4-98
4-19 Fluid-Bed Roaster 4-99
4-20 Reverberatory Furnace 4-103
4-21 Electric Smelting Furnace 4-104
4-22 Copper Converter 4-108
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LIST OF FIGURES (continued)
Page
4-23 Process Flow Diagram for Primary Copper 4-113
Smelting Showing Potential Industrial
Process Fugitive Emission Points
4-24 Blast Furnace With Typical Air Pollution 4-132
Control System
4-25 Reverberatory Furnace with a Typical Emission 4-133
Control System
4-26 Pot Furnaces with Typical Emission Control 4-134
System
4-27 Process Flow Diagram for Secondary Lead 4-138
Smelting Showing Potential Industrial Process
Fugitive Particulate Emission Points
4-28 Process Flow Sketch of Brass/Bronze 4-152
Reverberatory Furnace
4-29 Brass Reverberatory Furnace 4-154
4-30 Gas-Fired Rotary Brass Melting Furnace 4-155
4-31 Process Flow Diagram for Secondary Brass and 4-161
Bronze (Copper Alloy) Production Showing
Potential Industrial Process Fugitive
Particulate Emission Points
4-32 Production Flow Diagram for a Typical Gray 4-174
Iron Foundry
4-33 Cross-Section of a Cupola Furnace for Gray 4-175
Iron Production
4-34 Process Flow Diagram for Foundries Showing 4-184
Potential Industrial Process Fugitive
Particulate Emission Points
4-35 Method of Capturing Exhaust Gases From Cupola 4-189
Operations
4-36 Fabric Filter Control System on a Gray Iron 4-190
Cupola
4-37 Particulate Emissions as a Function of Venturi 4-195
Orifice Pressure Drop
XI
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LIST OF FIGURES (continued)
4-38 Venturi Gas Scrubbing System Installed on a 4-196
Foundry Cupola
4-39 Flow Diagram Depicting the Principal Units and 4-203
Auxiliaries in Modern Blast-Furnace Plant
4-40 Idealized Cross-Section of a Typical Modern 4-205
Blast-Furnace Plant.
4-41 Diagram which Illustrates the Principal Parts 4-207
of an Open-Hearth Furnace
4-42 Diagrammatic Section Along the Length of a 4-208
Liquid-Fuel Fired Open-Hearth Furnace
4-43 Schematic Elevation Showing the Principal 4-210
Operating Units of the Basic Oxygen Process
Steelmaking Shc-p
4-44 Schematic Cross-Section of a Heroult Electric 4-2]2
Arc Furnace
4-45 Process Flow Diagram for Iron Production 4-222
Showing Potential Industrial Process Fugitive
Particulate Emission Points
4-46 Ferroalloy Production Flow Diagram 4-256
4-47 Submerged-Arc Furnace for Ferroalloy Production 4-257
4-48 Ball Mill Process for Lead Oxide Manufacture 4-230
4-49 Barton Pot Process for Lead Oxide Manufacture 4-280
4-50 Flow Diagram for Type Metal Processes 4-293
4-51 Cross-Section of a Hydraulic Extrusion Press 4-300
4-52 Screw-Type Extrusion Press 4-300
4-53 Sources of Particulate Emissions in Cement 4-307
Plant
4-54 A Typical Rotary Cement Kiln and Clinker 4-308
Cooling System with Fabric Filter
4-55 Regenerative Glass Furnace 4-318
B-l Control system diagram for brass and bronze B-ll
Reverberatory Furnace
XI1
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LIST OF TABLES
Page
1 National Atmospheric Lead Emissions in 1975 x*
2 Lead Control Techniques xxv
3 Performance of Lead Emission Controls xxvi
2-1 Origins of Lead in United States 2-6
2-2 United States Consumption of Lead By Industry 2-7
2-3 Composition - Lead Air Emissions 2-11
2-4 Lead Particulate Size Distribution 2-14
2-5 Lead Control Techniques and Performances 2-15
2-6 Comparative Control Efficiencies for Lead 2-16
and Total Particulate
2-7 Fugitive Lead Emissions 2-37
2-8 Lead Emission Factors, Annual Emissions, and 2-45
Control Techniques
2-9 Relative Contribution of Lead Emissions From 2-50
All Sources
3-1 Operating Conditions for Determining Octane 3-2
Numbers of Fuels
3-2 ASTM Rating Scale for Automotive Fuels Above 3-10
100 Octane
3-3 Lead Consumption in U.S. Manufacture of 3-19
Lead Alkyl Gasoline Additives
3-4 Lead Particle Size Distribution From Vehicles 3-24
With Conventional Mufflers
3-5 Distribution of Particle Sizes in Exhaust at 3-25
260°F From Leaded and Unleaded Fuel
3-6 Lead Particle Size Distributions for Three 3-28
Production Vehicles
3-7 Melting Points of Selected Lead Compounds 3-33
3-8 Composition of Lead Deposits From A Lead Trap 3-34
Xlll
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LIST OF TABLES (continued)
Page
3-9 Amended Fuel Additive Regulations as of 3-38
September 28, 1976
3-10 Comparison of Properties of CNG, LNG, and 3-45
Gasoline
3-11 Estimated Sales-Weighted Fuel Economy For 3-60
American-Made Automobiles
3-12 Estimated Costs of DuPont Production Prototype 3-65
Lead Traps
3-13 Estimated Costs for Ethyl Tangential Anchored 3-67
Vortex Trap Based on 57.0 Mm (36,000-mi) Muffler
Life, 1973
3-14 Characteristics of Uncontrolled Exhaust Gas 3-81
From Pulverized-Coal-Fired Utility Boiler
3-15 Characteristics of Uncontrolled Exhaust Gas 3-82
From Cyclone Coal-Fired Boiler
3-16 Example Flue Gas and Precipitator Collection 3-87
Efficiency Data
3-17 Characteristics of Uncontrolled Exhaust Gas 3-95
From Oil-Fired Boilers
3-18 Characteristics of Uncontrolled Exhaust Gas 3-101
From Municipal Incinerators
3-19 Design Parameters for Electrostatic 3-105
Precipitators on Incinerators
3-20 Characteristics of Uncontrolled Exhaust Gas 3-116
From Medium and Large Waste Oil-Fired Boilers
4-1 Typical Exhaust Parameters for Battery 4-29
Manufacturing Operations
4-2 Lead Control Techniques and Associated Costs 4-32
for Lead-Acid Battery Plants
4-3 Lead Removal Efficiency for Well-Controlled 4-34
Processes
xiv
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LIST OF TABLES (continued)
4-4 Lead Emissions from Ore Grinding and Crushing 4-39
Operations
4-5 Characteristics of Uncontrolled Exhaust Gas 4-48
from Lead Sinter Machine
4-6 Characteristics of Uncontrolled, Undiluted 4-51
Exhaust Gas From a Lead Blast Furnace
4-7 Characteritics of Uncontrolled Exhaust Gas 4-54
From a Lead Dross Reverberatory
4-8 Estimates of Fugitive Dust Emissions From 4-55
Operations at one Primary Lead Smelter
4-8a Estimates of Fugitive Dust Emissions From 4-56
Operations at Two Primary Lead Smelters
4-9 Particle Size Distribution of Flue Dust from 4-5S
Updraft Primary Lead Sintering Machine
4-10 Performance of Blast Furnace and Dross 4-66
Reverberatory Furnace Baghouse
4-11 Characteristics of Uncontrolled Exhaust Gas 4-77
From a Zinc Sinter Machine
4-12 Lead Emissions at Zinc Sinter Machines 4-78
4-13 Characteristics of Uncontrolled Exhaust Gas 4-81
From Horizontal Zinc Retorts
4-14 Characteristics of Uncontrolled Exhaust Gas 4-83
From A Vertical Zinc Retort
4-15 Lead Emissions - Zinc Retorts 4-85
4-16 Fugitive Lead Emission Sources and Estimated 4-86
Uncontrolled Particulate Emission Factors
4-17 Characteristics of Uncontrolled Exhaust Gas 4-101
From A Copper Roaster
4-18 Characteristics of Uncontrolled Exhaust Gas 4-106
From a Copper Reverberatory Furnace
4-19 Characteristics of Uncontrolled Exhaust Gas 4-110
From a Copper Converter
xv
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LIST OF TABLES (continued)
Page
4-20 Uncontrolled Fugitive Emissions From Copper 4-112
Smelting Operations
4-21 Chemical Characteristics of Fugitive 4-114
Particulate Emissions From Various Process
Steps in Primary Copper Smelting
4-22 ESP Performance on Copper Reverberatory 4-118
Furnace and Roaster Combined Exhaust Gas Streams
4-23 ESP Performance on Two Copper Converter 4-119
Operations
4-24 Characteristics of Uncontrolled Exhaust Gas 4-136
for Secondary Lead Blast Furnace
4-25 Uncontrolled Exhaust Gas Characteristics for 4-137
Secondary Lead Reverberatory Furnace
4-26 Secondary Lead Fugitive Dust Sources and 4-137
Emissions
4-27 Performance of a Fabric Filter on a Secondary 4-143
Lead Reverberatory Furnace
4-28 Particulate Emissions From Brass and Bronze 4-158
Ingot Production
4-29 Characteristics of Uncontrolled Exhaust Gas 4-159
From A Brass and Bronze Reverberatory Furnace
4-30 Lead Emissions From Brass and Bronze 4-163
Production in 1974
4-31 Particulate Emissions From a Brass and Bronze 4-165
Reverberatory Furnace
4-32 Characteristics of Typical Exhaust Gas From 4-181
Gray Iron Melting Furnaces
4-33 Lead Emission Factors and Annual Lead Emissions 4-183
for the Gray Iron Foundry Industry
4-34 Emission Characteristics for Various Foundry 4-186
Operations
xvi
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LIST OF TABLES (continued)
Page
4-35 Dust and Fume Emissions From Gray Iron Cupolas 4-187
4-36 Fabric Filter Performance Test Results on a 4-192
Gray Iron Electric Arc Furnace
4-37 Production for Iron and Steel Industry in 1975 4-200
4-38 Characteristics of Uncontrolled Exhaust Gas 4-214
From Sintering Machines
4-39 Characteristics of Uncontrolled Exhaust Gas 4-217
From Iron Blast Furnaces
4-40 Characteristics of Uncontrolled Exhaust Gas 4-219
From Open-Hearth Steel Furnaces
4-41 Characteristics of Uncontrolled Exhaust Gas 4-224
From Basic Oxygen Furnaces
4-42 Characteristics of Uncontrolled Exhaust Gas 4-225
From Electric Arc Furnaces
4-43 Summary of Performance Test Results on a 4-229
Fabric Filter Serving Sinter Plant
4-44 Performance of an Electrostatic Precipitator 4-234
Serving an Open-Hearth Furnace
4-45 Summary of Performance Test Results on a 4-235
Venturi Scrubbing System Serving a Basic
Oxygen Furnace
4-46 Performance of Fabric Filter Serving an 4-238
Electric-Arc Furnace
4-47 U. S. Ferroalloy Production in 1975 4-254
4-48 Characteristics of Exhaust Gas From Open 4-261
Electric Furnaces Processing Common Ferroalloys
4-49 Lead Emissions From Ferroalloy Production 4-266
4-50 Test Results on an Electric Arc Furnace 4-269
Equipped With Fabric Filter
xvn
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LIST OF TABLES (continued)
Page
4-51 Characteristics of Uncontrolled Exhaust Gas 4-284
From Lead Oxide Ball Mill and Barton Pot
Processes
4-52 Performance Test Results on Fabric Filter 4-287
Systems
4-53 Characteristics of Uncontrolled Exhaust Gas 4-311
From Portland Cement Kiln
A-l Prefixes for the SI System of Measurement A-2
A-2 Conversion. Factors A-4
B-l Steps To Determine Total Equipment Costs B-2
B-2 Capital Cost Bases B-3
B-3 Annualized Cost Bases B-4
B-4 Retrofit Factors B-5
B-5 Characteristics of Uncontrolled Exhaust Gas B-10
From a Brass and Bronze Reverberatory Furnace
B-6 Determination of Capital Costs for Particulate B-12
Control System for a Brass and Bronze
Reverberatory Furnace
B-7 Control System Annual Operating Cost B-13
XVlll
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SUMMARY
This report documents atmospheric emissions of lead
(Pb) and its compounds from various sources, methods for
controlling these emissions, and approximate costs for
implementing these control methods. Estimates of energy
and environmental impacts are given for specific model
plants.
Lead and its compounds enter the atmosphere from com-
bustion of fuels, especially leaded gasoline, and from
industrial activities. Rural ambient air levels are
commonly below 0.5 yg/m whereas urban air lead levels are
mainly 1 to 2 yg/m . In highly populated areas daily
averages may exceed 3 to 5 yg/m and in dense traffic, lead
levels have been known to exceed 20 yg/m for several hours.
Near large stationary sources, levels have exceeded 300
yg/m .
In 1975, atmospheric emissions of lead in the United
States amounted to 141 Gg (155,900 tons),* of which 90.4
percent was contributed by gasoline combustion. These
emissions are summarized by source in Table 1.
*
The Appendix presents common conversion factors for
International and English systems of measurements.
xix
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Table 1. NATIONAL ATMOSPHERIC LEAD EMISSIONS IN 1975
Gasoline combustion
Coal combustion
Oil combustion
Solid waste incineration
Waste oil disposal
Lead alkyl production
Storage battery production
Ore crushing and grinding
Primary lead smelting
Primary copper smelting
Primary zinc smelting
Secondary lead smelting
Brass and bronze production
Gray iron production
Ferroalloy production
Iron and steel production
Lead oxide production
Pigment production
Cable covering
Can soldering
Type metal
Metallic lead products
Cement production
Lead glass production
Total
Megagrams
127,800
228
100
1,170
5,000
1,000
82
493
400
1,314
112
750
47
1,080
30
605
100
12
113
63
435
77
312
56
141,380
Tons
140,900
257
110
1,296
5,480
1,100
90
544
440
1,444
124
830
52
1,192
33
667
110
13
125
70
480
85
344
62
155,880
XX
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SOURCES OF LEAD AIR EMISSIONS
Lead emission sources can be categorized into three
groups: 1) combustion sources, which emit lead by volatilization
of lead components contained in the fuel or in refuse; 2)
metallurgical sources, which generate lead emissions by
volatilization or mechanical action from melting and processing
of metallic ores and materials; and 3) manufacturing sources,
which generate lead emissions by using refined lead as the
raw material to produce a lead-containing product. All
sources listed in Table 1 are considered in this study.
The nature of lead emissions depends on their origin
and on the mechanism of formation. High-temperature combustion
and smelting processes generate submicron particulate lead
fumes. Lead emissions from material handling and mechanical
attrition, as in battery manufacturing, consist of larger-
sized dust particles. The main chemical forms of lead
emissions include elemental lead (Pb), oxides of lead (PbO,
Pb02, Pb203, etc.), lead sulfates and sulfides (PbS04,
PbS, etc.), alkyl lead (Pb(CH3)4, Pb(C2H5)4), and lead
halides.
EMISSION FACTORS
Emission factors for lead were developed for each
source category; they are based on source tests, particulate
chemical analyses in the literature, industry responses,
xxi
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material balances, and engineering judgment. Because data in
the literature are limited, most of the emission factors
should be regarded as approximations; they do provide guide-
lines for estimating emissions from large groups of sources.
In many processes, lead emissions are a function of the lead
content of the charge or raw materials, for which data are
highly variable and sparse. In addition, the efficiency of
common particulate control devices with respect to lead
particulates is not well documented.
NATIONAL EMISSION INVENTORY
Annual emissions from each source category are determined
by use of (1) the uncontrolled emission factor, C2) the 1975
production output or consumption, and (3) an overall average
emission control factor for each source. Production and
consumption rates are fairly reliable. Emission factors and
overall control efficiency values are inherently less accurate
because of the limited availability of source-specific data.
The overall collection efficiencies for lead are assumed
equivalent to those for collection of nonlead particulates.
This assumption has been verified by limited EPA source tests
2
on fabric filters. For ESP's and wet scrubbers, some recent
information indicates differences in the collection efficiency
*> fi 7 8
between particulates and lead. ' ' ' Lead compounds are
probably less efficiently removed by ESP and wet scrubbers
whenever lead emissions are concentrated in the very fine
particulate sizes.
xxi i
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EMISSION TRENDS AND PROJECTIONS
Lead emissions from combustion of gasoline can be expected
to decrease by about 65 percent by 1985 as levels of lead in
gasoline are reduced from the current 0.45 g/litre (1.7 g/gal)
to 0.13 g/litre (0.5 g/gal) and as sales increase at 2 percent
per annum. These factors represent a reduction of 58 percent
of total 1975 lead emissions. They will also result in
reduction of lead emissions from waste oil combustion because
of a proportionate reduction in lead content, from lead alkyl
manufacturing because of reduced production plans. Federal
new source performance standards for particulate will also
strongly influence future lead emissions. Following are esti-
mates of 1985 lead emissions: gasoline combustion 44.9 Gg
(49,500 tons); stationary combustion sources, 3.7 Gg (4038
tons); and industrial processes, 4.2 Gg (4650 tons). These
values total 52.8 Gg (58,200 tons) of lead emissions, a reduc-
tion of about 63 percent from 1975 emissions.
CONTROL TECHNIQUES
Emissions of lead particulates from automotive sources
can be reduced by installing control devices, by reducing
or eliminating the lead content of gasoline, or by a combina-
tion of these methods. The Federal law requires the reduction
of the average lead content in gasoline from 0.45 g Pb/litre
(1.7 g Pb/gal) to 0.13 g Pb/litre (0.5 g Pb/gal) by 1979 which
should reduce gasoline lead emissions substantially.
XXI11
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Application of particulate traps on automotive exhaust systems
is under investigation and is discussed in detail in this
document. However, there are no traps installed commercially
at this time.
For stationary source emissions, the use of high-efficieny,
fine particulate controls such as electrostatic precipitators
(ESP), fabric filters, and wet scrubbers is reviewed. Few
processes incorporate control devices specifically for lead
control. Rather, these devices are installed for collection
of particulate to comply with state or federal regulations
and/or to recover valuable product. Control techniques
described herein are not, therefore, intended exclusively for
lead control, but do offer potential for reducing lead emissions
Table 2 shows the lead control techniques that are available
or that are used by the various lead emission sources.
Selection of a control strategy must be based upon the
required efficiency, gas stream characteristics, particle
characteristics, space restrictions, and many other site-
specific, economic, and technical factors. Also, the lead
emissions and the effects of lead pollution can be reduced by
relocation or shutdown of sources, fuel substitution, process
changes, improvement of operating practices, and atmosphere
dispersion techniques. Table 3 shows the possible lead
emission reductions with the various control techniques
available.
COST OF CONTROL
The incremental costs to the consumer of nonlead motor
xxiv
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vehicle fuels are difficult to assess because they involve
extremely complex technical and political factors.
TABLE 2
LEAD CONTROL TECHNIQUES
Controlled Source
Principal Method of ControjL
Gasoline combustion
Waste oil disposal
Metallurgical processes
Lead alkyl manufacture
Combustion and incineration
Industrial processes
Reduce Pb in gasoline.
Pretreat before burning
Blend with fuel oil
Reduce Pb in gasoline
Fabric filters, ESP
Scrubbers, fabric filters
ESP
Fabric filters, scrubbers
xxv
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TABLE 3
PERFORMANCE OF LEAD EMISSION CONTROLS
Control Device
Possible Emission Reduction
Lead particulate
traps-autos
Fabric filters
Scrubbers
ESP
Cyclone collectors
-907.
95-99.997o
80-997o
95-99.77o
-857o
Assuming that lead particulates are captured with
the same control efficiency as for total particulates.
XXVI
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Results of some cost studies (Section 3.1.3) indicate that the
incremental consumer cost of controlling lead emissions by
requiring the use of nonleaded gasoline ranges from 1 to 4
cents per gallon.
Incremental costs for various types of particulate and
lead collection devices range from about $5 to $20 per new
automobile, depending upon the type of device. Retrofit
installations will cost considerably more.
The capital and annualized costs of particulate emission
control are given for each industrial process and control
alternative. These data are based on actual operations or
engineering cost analyses and are escalated to reflect mid-
1976 costs. These costs generally reflect the cost of com-
pliance with existing regulations for particulate emissions.
Costs attributable to control of lead emissions are not pro-
vided, since they would depend on the degree of control
required at a specific site, and it is generally impossible to
allocate lead control costs from costs for total particulate
control.
IMPACTS OF CONTROLS
The environmental and energy impacts of meeting an air
quality standard for lead are thought to be negligible.
Relatively few plants may be affected by such a standard. The
additional wastewater and solid wastes generated above that
generated by SIP controls will be insignificant. The energy
xxvii
-------
impact may be significant at plants which utilize wet scrubbers
or which require additional control equipment. In this docu-
ment, order of magnitude estimates are given for particulate
SIP control impacts for major sources of lead. Generally,
impacts for lead control will be much less than for particu-
late control.
XXVlll
-------
REFERENCES
1. Scientific and Technical Assessment Report. Office
of Research and Development. U. S. Environmental
Protection Agency. Washington, D. C. EPA 600/6-
75-OOX. STAR series. February 1975.
2. Preferred Standards Path Analysis on Lead Emissions
from Stationary Sources. Emission Standards and
Engineering Division. U. S. Environmental Protection
Agency. Research Triangle Park, N. C. September 4,
1974.
3. Environmental Protection Agency Regulations of Fuels
and Fuel Additives. 40 CFR 42675. Part 80. Subpart
B. Sec. 80.20 (a) (1). September 28, 1976.
4. Control Techniques for Particulate Air Pollutants.
AP-51, U. S. Environmental Protection Agency. Office
of Air Programs. Research Triangle Park, N. C. January
1969. 215 p.
5. KaaKinen, J. W., R. W. Jordan, M. H. Lawasani, and
R. E. West. Trace Elements Behavior in Coal-Fired
Power Plants. Environmental Science and Technology.
Volume IX (9): 862-869. September 1975.
6. Lee Jr., R, E., H. L. Crist, A. E. Riley, and K. E.
MacLeod, Concentration and Size of Trace Metal Emissions
from a Power Plant, a Steel Plant, and a Cotton Gin.
Environmental Science and Technology. Volume IX (7):
643-647. July 1975.
7. Klein, D. H. et al. Pathways of Thirty-Seven Trace
Elements Through Coal-Fired Power Plant. Environmental
Science and Technology. Volume IX (10): 973-979.
October 1975.
8. Natusch, D. F. S. and C. A. Evans, Jr. Toxic Trace
Elements: Preferential Concentration in Respirable
Particles. Science. Volume 183: 202-204. January
1975.
XXIX
-------
1.0 INTRODUCTION
Pursuant to the authority delegated to the Administrator
of the Environmental Protection Agency, Control Techniques
for Lead Air Emissions is issued in accordance with Section
108 of the Clean Air Act as amended August 1977.
Lead air pollutants are generated from a wide variety
of sources. The physical and chemical characteristics of
exhausu gases containing lead dictate a variety of control
techniques and present unique control problems.
The many processes that generate lead air pollutants
are described individually in this report. Lead emission
factors are presented and are based on source performance
testing, chemical analysis of dusts collected by control
devices, industry responses, and engineering judgment.
Nationwide lead emissions for each source category are
estimated for 1975 based upon the emission factors, pro-
duction levels,and overall level of air pollution control of
each source.
Information on capital and annualized costs of install-
ing control equipment is presented for each source category.
It is not possible, in most situations, to distinguish
between costs of particulate control and costs of lead
1-1
-------
control. The control costs are, therefore, presented for
particulate control equipment, which coincidentally reduces
potential lead emissions with the same efficiency of collection,
Combustion of gasoline in internal combustion engines
represent the most significant single source of lead emissions,
comprising about 90.4 percent. Strategies for control of
lead emissions from motor vehicles are reduction of lead
content in the gasoline or installation of lead traps on
vehicle exhaust systems. These techniques and associated
costs are discussed at length. The implications of the
control of lead emissions from gasoline combustion are also
considered. Although the stationary sources contribute
relatively minor amounts of lead on an annual tonnage basis,
they may be of importance in some localities.
The effects of lead on health and welfare are to be
described in a companion document, Air Quality Criteria
for Lead.
1-2
-------
2.0 BACKGROUND INFORMATION
2.1 DEFINITIONS
FCJlowing are brief definitions of technical or uncommon
terms used throughout this document.
Alumina - The native form of aluminum oxide occurring as
corundum or in hydrated forms as a powder or crystalline
substance.
Aluminothermic - Pertaining to the process of reducing a
met a 11 ic~olcTde" to the metal and producing great heat by
mixing finely divided aluminum with the oxide, which is
reduced as the aluminum is oxidized.
Amine - One of a class of organic compounds that can be
considered to be derived from ammonia by replacement of one
or more hydrogens by organic radicals.
Antiknock - Resisting detonation or pinging in spark-ignited
engines or a substance, such as tetraethyl lead, added to
motor and aviation gasolines tc increase the resistance of
tne fuel to knock in spark-ignitc-d engines. Also known as
antidetonant.
Autoclave - An airtight vessel for heating and sometimes
agitatTng its contents under high steam pressure; used for
industrial processing, sterilizing, and cooking with moist
or dry heat at high temperatures.
Calcine - To heat at a high temperature without fusing, as
to heat unformed ceramic materials in a kiln, or to heat
ores, precipitates, concentrates, or residues so that
hydrates, carbonates, or other compounds are decomposed and
volatile material is expelled.
Compression Ratio - In internal combustion engines, the
ratio between the volume displaced by the piston plus the
clearance space to the volume of the clearance space.
-------
Cracking - A process used to reduce the molecular weight of
hydrocarbons by breaking molecular bonds of thermal, catalytic,
or hydrocracking methods.
Cupola - A vertical cylindrical furnace for melting gray iron
for foundry use; the metal, coke, and flux are put into the
tops of the furnace onto a bed of coke, through which air is
blown.
Dross - An impurity, usually an oxide, formed on the surface of
a molten metal.
Dust - Solid particles predominately larger than colloidal
size and capable of temporary suspension in air and other
gases. Derivation from larger masses through the application
of physical force is usually implied.
Electrothermic - Pertaining to the conversion of electric
energy into heat energy.
Extruder - A device that forces ductile or semisoft solids
through die openings of appropriate shape to produce a
continuous film, strip, or tubing.
Flyash - Fine particulate, essentially noncombustible refuse,
carried in a gas stream from a furnace.
Fugitive Emissions - Particulate matter which escapes from a
defined process flow stream due to leakage, materials charging/
handling, inadequate operational control, lack of reasonable
available control technology, transfer or storage.
Fumes - Particulate matter consisting of the solid particles
generated by condensation from the gaseous state, generally
after volatilization from melted substances, and often
accompanied by a chemical reaction, such as oxidation.
Galena - PbS - A bluish-gray to lead-gray mineral with
brilliant metallic luster, specific gravity 7.5, and hardness
2.5 on Mohs scale; usually occurs in cubic or octahedral
crystals, in masses, or in grains.
Gangue - The valueless rock or aggregates of minerals in an ore
Hydrometallurgy - Treatment of metals and metal-containing
materials by wet processes.
Kiln - A heated enclosure used for drying, burning, or firing
materials such as ore or ceramics.
2-2
-------
Lead - (Pb) atomic weight 207.19; atomic number 82. Meltine
point, 327.5°C. Bciiing point 1744°C; specific gravity
11.35 (20°C). Lead is a cumulative, poisonous metal, which
enters the environment largely through combustion and indus-
trial processes.
Linotype - A typesetting machine in which the type molds of
letters are arranged in lines; solid slugs, or lines of
type, are cast.
Mist - Fine liquid droplets suspended in or fclling through
a moving or stationary gas atmosphere.
Monotype - A printing technique in which a picture is
painted on a sheet of glass or metal and is transferred to a
sheet of paper by pressure.
Octane Number - A rating that indicates the tendency to
knock when a fuel is used in a standard internal combustion
engine under standard conditions; n-heptane is 0, isooctane
is 100; different test methods give research octane, motor
octane, and road octane values.
Opacity - The light flux transmitted by an emission plume
divided by the light flux incident upon it.
Particulate Matter - Matter in the form of small liquid or
solid particles.
Pyrometallurgical - Pertaining to high-temperature process
metallurgy.
Retort - A closed refractory chamber in which coal is
carbonized for manufacture of coal gas, or any vessel for
the distillation or decomposition of a substance.
Reverberatory Furnace - A furnace in which heat is supplied
by burning of fuel in a space between the charge and the low
roof.
Spreader Stoker - A coal-burning system where mechanical
feeders and distributing devices form a thin fuel bed on a
traveling grate, intermittent-cleaning dump grate, or
reciprocating continuous-cleaning grate.
Stereotype - A duplicate printing plate made from type and
cuts; a paper matrix, or mat, is forced down over the type
and cuts to form a mold, into which molten metal is poured,
resulting in a new metal printing surface that exactly
duplicates the oriyiiol,
-------
Trommel Screen - A revolving cylindrical screen used to
grade coarsely crushed ore; the ore is fed into the trommel
at one end, the fine material drops through the holes, and
the coarse is delivered at the other end.
Tuyere - An opening in the shell and refractory lining of a
furnace through which air is forced.
VIS Breaking - (Viscosity breaking) A petroleum refinery
process used to lower or break the viscosity of high-visco-
sity residuals by thermal cracking of molecules at rela-
tively low temperatures.
2.2 ORIGIN AND USE OF LEAD1'2
Lead production in the United States in 1975 was about
1.13 Tg (1.246 x 10 tons). The approximate total consump-
tion was 1.176 Tg (1.297 x 10 tons) the difference being
accounted for by imports and reduction in stocks. Lead is
mined primarily as galena and is generally associated with
zinc, silver, gold, and copper. Missouri mines account for
approximately 80 percent of the Nation's lead ore. Idaho
provides about 10 percent; Colorado and Utah produce most of
the remaining 10 percent. The total U.S. mine production
produces about 84 percent of the primary lead used in this
country.
Lead recovered from imported ores has been between 15.5
and 22.8 percent of the total U.S. lead production. Scrap
materials consumed by secondary smelters account for nearly
50 percent of lead production. New scrap is from drosses
and residues from a variety of sources. The remainder, old
scrap, is from batteries, cables, type metal, plumbing,
2-4
-------
ballast, and other minor contributors. The origins of lead
in the United States economy for the period 1971 through
1975 are reported in Table 2-1.
Lead consumption decreased significantly in 1975 in all
usage categories. Reductions in the requirements for
storage battery and gasoline lead additives manufacturing
were the major contributors to the decrease in lead consump-
tion. This decrease reflects the decreased demand for road
motor vehicles and restrictions on leaded fuels by the new model cars.
Table 2-2 shows the estimated lead consumption for each
major category. Figure 2-1 illustrates the flow of lead
through the U.S. economy in 1975.
2.3 TYPES OF LEAD EMISSIONS
The nature of lead emissions depend upon their origin
and the mechanisms of formation. An understanding of these
factors is necessary in evaluating the potential impact and
control of the emission sources.
Lead may be emitted as a dust with particle diameters
ranging from 1 to 150 ym. Dusts are usually produced by
mechanical activity. Fumes are generated by condensation,
sublimation, or chemical reaction and include particles
below 1 micron in diameter. Mists are liquid droplets
formed by water vapor condensation on solid particles or
atomization of liquid. Most atmospheric lead emissions are
2-5
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SCRAP
598(659)
EXPORT
454(50)
DOMESTIC
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483(532)
FOREIGN
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96(106)
METAL
IMPORTS
164(181)
STOCKS
68 (75)
SECONDARY
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METAL
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245(270)
CERAMICS
AND PIGMENTS
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ALKYLS
190(209)
BATTERIES
634 (699)
OTHER
36 (40)
EXPORT
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Figure 2-1. Approximate flow of lead through
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2-8
-------
in the form of dusts or fumes. Vapor emissions emanate from
the manufacture of high volatile alkyl lead compounds for
gasoline additives.
Chemical forms of lead emissions are generally ele-
mental lead (Pb) or lead oxides (PbO, Pb02, Pb-O , etc.).
Lead sulfide, lead sulfate, and lead halide particulates and
alkyl lead vapors are also emitted.
2.4 SAMPLING AND ANALYTICAL METHODS3
As part of the work done under EPA Contract No. 68-02-1219,
Arthur D. Little, Inc. has performed a review of the recent
literature pertaining to lead stack sampling and analysis. Their
recommendation was to employ a Modified EPA Method 5 sampling
train for sample collection, with lead analysis to be per-
formed by atomic absorption spectrometry (AAS). For their
immediate needs associated with NSPS, EPA has combined these
techniques in a working draft, "Determination of Lead Emis-
sions from the Manufacturing of Lead Batteries."
In this adaption of the Method 5 sampling train, 100 ml
of 0.1N HNO., is placed in each of the first two impingers to
facilitate collection of gaseous lead. Since no separation
of gaseous and particulate lead is attempted, a filter,
which is of high purity glass fiber, is located between the
third and fourth impingers as a backup collector.
A rigorous treatment with HNO_ of all sample-exposed
surfaces and containers, blank analyses of filters and 0.1N
2-9
-------
o, and the most recent revisions of the Method 5 sample
recovery procedure are all employed to insure that high
quality samples are obtained.
Since emissions from the manufacture of lead batteries
are relatively free of other pollutants, possible sample
matrix effects associated with AAS are not thought to be of
consequence insofar as the impinger portion of the sample
is concerned. However, as a precaution against this problem
with the filter portion due to the presence of the filter,
the analytical technique known as the "method of additions"
is used for that fraction of the sample.
EPA is now planning to extend this technique (which is
commonly employed by those who use AAS) to the impinger
portion for the general-lead emission measurement method.
Work is currently being initiated to confirm this approach
on a variety of sources.
2.5 SOURCES OF LEAD EMISSIONS
Lead emissions result from combustion, furnace operations,
smelting processes, mechanical processing operations, and
fugitive dust sources.
Table 2-3 shows the composition of lead emissions from the
major sources of lead emissions.
The most significant source of lead emissions is the
combustion of leaded gasoline, followed by the combustion of
waste oil.
Combustion of coal and oil and incineration of municipal
waste are also sources of lead. Industrial sources of lead
2-10
-------
TABLE 2-3
COMPOSITION - LEAD AIR EMISSIONS
Source
Nature of Emission
Gasoline combustion
Other combustion
Metallurgical operations
Lead alkyl manufacture
Industrial processes
Particulate - Lead halides,
oxyhalides
Particulate with lead oxides
Particulate with lead oxides
TEL and TML vapor
Particulate - lead oxides
Particulate with lead oxides, Pb
2-11
-------
include the production of lead alkyls, primary and secondary
nonferrous metals, ferrous metals and alloys, and lead oxides.
Other sources of lead include the manufacture of lead acid
batteries, cable covering, can soldering, cement production,
type metal operations, and manufacture of metallic lead
products and lead glass. Figure 2-2 shows the location of some
of these industrial sources of lead emissions.
2.6 CONTROL DEVICES
Lead emissions from all sources except gasoline additives
manufacturing are in the form of particulate matter and are,
therefore, controlled with particulate control equipment.
Typical particulate size distribution ranges of lead are shown
in Table 2-4 for the major sources of lead emissions. Con-
ventional electrostatic precipitators (ESP), wet scrubbers, and
fabric filters are primarily considered in this study as control
techniques. Table 2-5 shows the lead control techniques that
are in use or have been developed for the various lead
emission sources.
Limited EPA tests of fabric filters, ESP, and wet scrubbers
indicate that overall collection efficiencies for lead and
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nonlead particulate are about the same. Table 2-6 shows the
results of the emission tests on six lead sources. In all
cases except one, the control efficiency for lead was com-
parable to that for particulate. In that one case, the
collection efficiency for lead was better than for particulate.
For ESP's and wet scrubbers, there is also some evidence
regarding possible differences in collection of lead and
nonlead particulate.11'12'13'14
2-12
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LEAD PARTICULATE SIZE DISTRIBUTION
Lead Source
Particulate Sizes
Gasoline combustion
Waste oil burning
Solid waste incineration
Gray iron production
Primary lead smelting
Sintering
Blast Furnace
Reverberatory furnace
40-75%
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TABLE 2-6
COMPARATIVE CONTROL EFFICIENCIES FOR LEAD
AND TOTAL PARTICIPATE
Source
Primary Lead
Smelter
(Blast Furnace)
Secondary Lead
Smelter
a. Blast
Furnace
b. Refining
Kettles
Battery
rtanufacture
a. Paste Mixer
b. Three
Process Opei
tion (Stacki
Burning, am
Battery
Assembly)
Lead Oxide
Manufacture
a. Furnace and
Hanrner Mill
b. In-plant
ventilation
Copper Swelter
(Converter)
Control
System
Water Spray
Chamber,
Baghouse
Afterburner,
Cooling Tower,
Baghouse
Venturi
Scrubber,
Rotoclone
Scrubber
Baghouse
a-
ng,
i
Cyclone,
Baghouse
Baghouse
Electrostatic
Preci pita tor
Collection Efficiency, *
Particulate
Front Half1
99.21
99.91
84.23
83.4
35.2
99.96
99.94
94
Total Train1^
98.51
99.09
82.57
77.3
28.8
99.96
99.90
834
Lead
Front Half1
97.66
99.93
87*95
85
98.2
99.97
99.1
5
Total Train2
97.65
99.92
87.95
84.9
96.7
99.97
99.1
90
2-16
-------
Front Half - refers to the probe, cyclone, and filter of
the EPA p.articulate sampling triin.
2
Total Train - refers to the total EPA particulate sampling
train, including the front half and the impingers.
3
See reference 10. Tests conducted according to EPA Method 5
with modifications.
The lower collection efficiency based on measurements from
the total train compared with that based on measurements
from the front half of the train is suspected to be due
to SO^ interference. (Personal verbal communication between
Robert Statnick and Susan Wyatt on May 8, 1974).
Not available.
2-17
-------
ESP and wet scrubbers will be less efficient for removal of
lead compounds that concentrate on the very fine part ioiilat .*
sizes. For evaluations in this Document, the collect .^
efficiencies of all devices a? e considered to be the ?arae with
respect to lead and nonlead particulates, and Table 2-5 also
shows the feasible lead emission reduction wit! the various
control techniques.
Detailed analyses of the design and performance of these
control devices and procedures are presented in references 15
through 18. Criteria for selection of gas cleaning devices
are illustrated in Figure 2- 3
2-1:
-------
EMISSIONS AND EMISSIONS
STANDARDS
DETERMINES COLLECTION EFFICIENCY
CONTROL EQUIPMENT ALTERNATIVES
ELECTROSTATIC
PRECIPITATOR
-J
^-_
.
WET
COLLECTOR
GAS STREAM
CHARACTERISTICS
VOLUME
TEMPERATURE
MOISTURE CONTENT
CORROSIVENESS
ODOR
EXPLOSIVENESS
VISCOSITY
WASTE TREATMENT
SPACE RESTRICTION
PRODUCT RECOVERY
i
DRY
CENTRIFUGAL
COLLECTOR
i
_-
PARTICLE
PROCESS
i
CHARACTERISTICS
IGNITION POINT
SIZE DISTRIBUTION
ABRASIVENESS
HYGROSCOPIC NATURE
ELECTRICAL PROPERTIES
GRAIN LOADING
DENSITY AND SHAPE
PHYSICAL PROPERTIES
^
PLANT
FACILITY
ENGINEERING STUDIES
HARDWARE
AUXILIARY EQUIPMENT
LAND
STRUCTURES
INSTALLATION
START-UP
i
WATER AVAILABILITY
FORM OF HEAT RECOVERY
(GAS OR LIQUID)
COST OF
CONTROL
POWER
WASTE DISPOSAL
WATER
MATERIALS
GAS CONDITIONING!
LABOR
TAXES
INSURANCE
RETURN ON
INVESTMENT
SELECTED
GAS CLEANING SYSTEM
DESIRED EMISSION RATE
Figure 2-3. Criteria for selection of gas cleaning devices.
19
2-19
-------
2.6.1 Fabric Filters
When high efficiency is required for collection of
small particles, the most widely used method of gas cleaning
is the fabric filter. Figures 2-4 through 2-6 illustrate
popular types of fabric filters. Particles are initially
captured and retained on cloth fibers by means of inter-
ception, impingement, diffusion, gravitational settling, and
electrostatic attraction. Once a mat or cake of dust is
formed on the fabric, collection occurs also by sieving.
Periodically the fabric is cleaned to allow collection and
disposal of the dust and to maintain the pressure drop
across the filter within practical limits. Fabrics are
available that permit operation at temperatures of up to
290°C (550°F) and provide chemical resistance against con-
19
stituents in the gas stream.
The gas flow rate and dust concentration, in conjunc-
tion with specific flow-resistance properties of the dust
deposited on the fabric, determine the required cloth area
for operation at a specified pressure drop. Pressure drop
is generally selected in the range of 0.75 to 1.0 kPa (3 to
4 in. H~0), although some systems operate well in excess of
3 -2
2.5 kPa (10 in. H20). Superficial filter velocity, m /s-m
2
cloth (acfm/ft cloth), commonly called the air-to-cloth
-3 3 -2
ratio, generally ranges from 5.0 to 7.5 x 10 m /s-m
2-20
-------
CUSh SIR
- "' SIDE
fiLTER
CEH
PUTE
Figure 2-4. Fabric filter with mechanical shaker.
(Courtesy of Wheelabrator-Frye Corp., Pittsburgh)
15
Figure 2-5. Envelope type fabric filter with automatic
reverse-air cleaning mechanism. I-*
(Courtesy of W. W. Sly Mfg. Co., Cleveland, Ohio)
2-21
-------
Figure 2-6. Reverse-jet fabric filter.15
(Courtesy of Western Precipitation/Joy Mfg. Co., Los Angeles)
2-22
-------
2
cloth (1 to 15 acfm/ft cloth) depending on gas stream and
particle characteristics and on the cleaning mechanism.
A variety of cleaning mechanisms are used to remove
dust from the filter media: 1) mechanical shaking; 2) air
shaking; 3) air bubbling; 4) jet-pulse; 5) reverse air
flexing; 6) reverse jet; and 7) repressuring. Very small
2 2
baghouses, less than 93 m (1000 ft ) of cloth, are fre-
quently cleaned by manual rapping. This method is unreli-
able to the extent that it depends on the operator's work
habits. Manometers are recommended to indicate pressure
drop when cleaning is done manually. Mechanical shakers,
which are most common, are driven by electric motors that
provide a gentle but effective cleaning action. Air shaking
is accomplished by causing air to flow through the rows of
bags to impart a cleaning action. In cleaning by air bub-
bling, a jet of air is released at the top of the bags,
causing them to ripple; air bubbling has not been proved
effective at high air-to-cloth ratios. In the jet-pulse
method a jet of compressed air released through a venturi
section at the top of the bag cause the bags to pulse out-
ward; jet pulse cleaning provides for automatic, continuous
cleaning with uniform pressure drop and permits higher air-
to-cloth ratios. Reverse air flexing is achieved by a
double or triple cycle deflation of the bags followed by
2-23
-------
gentle inflating through low-pressure reverse flow. Re-
verse jet cleaning is done with a traveling ring of com-
pressed air, which moves up and down the outside of the
tubular bag. Repressuring cleaning is accomplished a low-
pressure, high-volume, reverse flow of air through the
19
bags.
A variety of woven and felted fabrics is available for
diverse applications. Selection of a filter medium involves
consideration of temperature, particle characteristics, cor-
rosivity and reactivity of the gas stream, type of cleaning
mechanism, and desired pressure drop. Bag life, which
varies greatly with operating conditions, is on the order of
1 to 3 years.
Operational problems with fabric filters include
fluctuations in gas flow and dust loading, high temperature
and humidity, condensation, and reactivity of gas and/or
dust particles with system components. These problems
affect pressure drop, efficiency, and bag life. Maintenance
includes regular inspection, greasing of mechanical parts,
disposal of solid waste and replacement of worn bags.
2.6.2 Wet Collectors
Wet collectors are available in a wide range of costs
and performance characteristics. Wet collectors, or scrub-
bers, are popular because they can remove both solid and
2-24
-------
gaseous components from flue gases with high temperatures,
moisture content, and corrosivity. High-efficiency collection
of submicron particles requires very high expenditure of
energy. Efficiency can be related to pressure drop for a
specific particle size. Treatment of the wastewater generated
by wet collectors can be difficult and expensive.
In orifice-type scrubbers the orifice increases the
velocity of the gas to provide for liquid contact. Flow of
gas through a restricted passage partially filled with water
causes dispersion of the water as centrifugal forces, impinge-
19
ment, and turbulence cause the collection of particles.
Figures 2-7 and 2-8 show two types of orifice scrubbers.
Pressure drops range from 1 kPa to 3 kPa (4 to 12 in. of l^O).
3
Water requirements are from 0.03 to 0.67 1/m (0.2 to 5 gpm/
3
10 acfm), depending upon gas temperature and desired con-
20
centration of solids in the slurry.
Mechanical scrubbers include devices in which the
water spray is generated by a rotating disc or drum, promoting
high turbulence to promote collision between water droplets
and dust particles. Figure 2-9 illustrates a typical
mechanical collector.
In a mechanical-centrifugal collector, water sprays are
added to the inlet of a rotary blade fan. Collection is due
primarily to impingement of dust particles on the wetted
rotary blades. The water film on the blades flushes away
2-25
-------
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2-27
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2-28
-------
the collected dust. Figure 2-10 shows a popular mechanical-
centrifugal collector. Pressure drop is about 1.6 kPa
(6.5 in. of H^O) with a maximum pressure drop of 2.25 kPa
(9 in. of l^UO). Water requirements range from 0.1 to 0.2
(0.75 to 1.5 gpm/1000 acfm). The chief advantages are low
space requirements, moderate power requirements, low water
consumption, and a relatively high scrubbing efficiency of
70 to 80 percent.
2-29
-------
Impingement plate scrubbers, as shown in Figure 2-11
consist of a tower equipped with one or more impingement
stages, mist-removal baffles, and spray chambers. The
plates are perforated, and a weir controls the level of
water on the plate. The water flows through a downcomer to
the next lower stage as dust-laden gas passes through the
perforated plates. Overall collection efficiencies are as
high as 90 to 98 percent for pressure drops of 2 to 4 kPa (8
to 16 in. H20). Water requirements are 0.4 to 0.7 litre/m
(3 to 5 gpm/103 acfm). 19
In a venturi scrubber, the flue gases are passed
through a venturi throat where water is injected. Gas
velocities in the throat range from 75 to 100 m/s (15,000 to
20,000 fpm). Pressure drops can range from 2.5 kPa (10 in.
H20) to over 20 kPa (80 in. H_0). The venturi provides very
intimate contact and relatively higher collection effi-
ciencies. Liquid-to-gas ratios are from 0.4 to 2 litre/m
(3 to 15 gpm/103 acfm). The wetted particles and droplets are
collected by a cyclone spray separator following the ven-
turi. Figure 2-12 illustrates the operation of a common
venturi scrubber system.
2.6.3 Electrostatic Precipitators
The high-voltage electrostatic precipitator (ESP) is
commonly used at coal fired boilers, smelters, steel furnaces,
2-30
-------
ENTRAPMENT
STAGE
WATER
INLET
ROTATING
AIR STREAM
IMPINGEMENT
STAGES
AIR
INLET
WASH 9
WASH 8
WASH 7
WASH 6
WASH 5
WASH 4
WASH 3
WASH 2
WASH 1
Figure 2-11. Centrifugal-impingement scrubber.
(Courtesy of Schneible Co., Detroit, MI)
15
2-31
-------
Figure 2-12. Venturi scrubber design and operation
15
2-32
-------
cement kilns, and many other high-exhaust-volume
applications for control of particulate matter.
Electrostatic precipitation separates particles from a
gas stream by three basic steps: electrical charging of the
dust particles, collection of the dust on a grounded surface,
and removal of the dust. The charge is applied by passing
the dust-laden gas stream through a high-voltage direct-
current corona established between an electrode and the
grounded collecting plate. Particles become highly charged
in a fraction of a second and migrate toward the collecting
surface. The dust is removed by mechanical rappers or by
18
flushing with water. Parameters that must be considered in
ESP design include voltage, electrical energy, dust resis-
tivity, velocity, flow distribution, sectionalization,
collection area, and residence time. Particle and gas
stream characteristics determine the ease of collection, the
major factors being resistivity (optimum < 10 ohm - cm)
and size distribution of the particles and temperature and
moisture content of the gas. For example, in coal-fired
boiler applications, the sulfur content of the coal greatly
influences the collection efficiency of the ESP since
18
sulfates change the resistivity of the particulates.
Gas conditioning systems, primarily spray chambers, are
commonly required to decrease temperature and particle
2-33
-------
resistivity prior to precipitation. Addition of moisture
decreases resistivity, while in the temperature range of 121 C
to 204°C (250°F to 400°F) resistivity increases with temperature
However the net result in moisture addition is a decrease in
resistivity. Some systems condition the gases by adding
small amounts of sulfur trioxide or ammonia. Cooling can also
19
be accomplished by heat transfer or air dilution.
Common problems in ESP operation are condensation of
moisture, corrosion, gas expansion, rapping problems,
high resistivity, nonuniform gas distribution, iand electrode
failure.18
Figure 2-13 illustrates the major construction features
of a typical ESP.
2.7 FUGITIVE LEAD EMISSIONS
Lead emissions from fugitive dust sources may be signifi-
cant, in terms of health effects, in primary and secondary lead
smelting, copper and zinc smelting, and production of lead
oxide and gasoline additives. Examples of fugitive dust
sources include uncovered railroad cars, raw material unload-
ing, product loading, storage piles, furnace tapping, con-
veyors, grinders, transfer points, leaks, and handling of
dust collected by control systems.
Fugitive dust emissions containing lead can be controlled
by maintenance, enclosure, and wetting. Maintenance includes
2-34
-------
Ml RAPPERS
HTCABLE FROM
RECTIFIER
SHEIL
HOPPERS
HOPPER BAFFLES
WIRE TENSIONING
WEIGHTS
Figure 2-13. Major design features of a common ESP.
2-35
-------
sealing of furnaces and ductwork. Furnace charging, furnace
tapping, transfer points, conveyors, and mechanical equipment
can be enclosed and vented to an adjacent control device.
Uncovered railroad cars, trucks, raw materials, and unloading
areas can be enclosed or wetted.
Lead and particulate emission factors for fugitive dust
sources are estimated for ore mining, crushing, and grinding,
primary copper, lead, and zinc smelting, and secondary lead
smelting, and are presented under these sections in the docu-
ment.
Other sources of fugitive dust emissions containing lead
do not appear to be a major problem in terms of health impact
on surrounding communities. Iron, steel, and gray iron, and
non-ferrous metals production operations may have particulate
fugitive dust problems. Table 2-7 summarizes some major
fugitive lead emission sources and some available control
techniques for non-ferrous smelters.
2.8 CONTROL COSTS
Knowledge of the relationships between the cost of
control and amount of pollutant reduction is useful in
assessing the impact of control on product prices, value
added to the product, profits, and investments. Seldom are
control systems installed specifically for control of lead
emissions, since lead control is usually coincidental with
particulate control. It is difficult, therefore, to deter-
mine distinct incremental costs for control of lead
2-36
-------
TABLE 2-7
FUGITIVE LEAD EMISSIONS
Significant Sources
Smelting of primary lead, zinc, copper, and secondary lead.
Operations
Transport, storage, charging, furnace tapping.
Control Techniques
Maintenance - seal furnaces and ducts.
Enclosure - furnace charging, tapping, material handling,
Wetting - roads, piles, trucks.
2-37
-------
emissions; the costs presented in this report are for the
broader category of particulate control.
Capital and annualized costs may be developed for a
system having a certain flow rate and desired control effi-
ciency. Under actual operating conditions, however, flow
rates and efficiencies may vary. In estimating flow rates
for each process, the flow rates may be highly variable,
depending upon hooding configuration and other site-specific
factors.
Figure 2-14 illustrates the factors influencing the
cost of gas cleaning systems. For a specific control de-
*
vice, gas flow rate, and degree of pollutant reduction,
capital costs will vary from one application to another.
Variations are due to differences in particle and gas stream
characteristics, operating requirements, gas conditioning,
special materials (stainless steel, ceramic coatings, etc.),
insulation, instrumentation, waste treatment, and other
factors. Significantly higher costs are usually incurred
for retrofitting control systems on existing facilities.
Complete engineering cost estimates were made for the fol-
lowing industries:
Lead Additives Production
Battery Manufacturing
Primary Lead Smelters
2-38
-------
en
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CQ
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2-39
-------
Primary Zinc Smelters
Primary Copper Smelters
Secondary Lead Smelters
Brass and Bronze Production
Gray Iron Foundries
Q
Lead Oxide Manufacturing
Ferroalloys Production
Municipal Incineration
It cannot be overemphasized that the costs developed
for the above -processes apply only for the assumptions made
and are within a range of + 30 percent of the actual value.
For a specific model plant and control configuration, costs
can vary widely due to volumetric flow rate and material and
equipment selection. In addition, installation charges are
dependent on many site-specific factors and also vary widely.
Additional costs incurred due to retrofitting new equipment
in an existing plant are difficult to estimate and will vary
significantly from plant to plant. Most existing plants will
have some equipment installed and operating which is suitable
for use, i.e., fan, ductwork, and cooling devices. The costs
presented in this document include ductwork, cooling equipment,
fan, etc. Since most existing plants may have hooding systems
and stacks already installed, these costs are not included.
Detailed cost analyses are available from EPA - Office of
Air Quality Planning and Standards upon request.
o
Lead oxide manufacturing is generally part of lead-acid
battery manufacturing plants.
2-40
-------
Control costs given for sources other than those listed
above were obtained from the literature references indicated.
Cost data reflect mid-1976 prices. A detailed dis-
cussion of the costing procedure and assumptions is pre-
sented in Appendix B.
2-41
-------
2.9 EMISSION ESTIMATES AND EMISSION FACTORS
An emission factor is an estimate of the emissions
generated from a specific activity divided by a value
indicating the level of that activity. The emission factor
for production of gray iron in a cupola is expressed as g
Pb/kg product (Ib Pb/ton). The emission factor for combus-
tion of distillate oil is expressed as kg Pb/10 litre
3
(lb/10 gal) of oil fired. The emission factors may also be
expressed as a function of the lead content of the material
processed. The lead emission factor for combustion of coal
is 0.8L g Pb/kg coal (1.6L Ib Pb/10 ton) where L is the
lead content in ppm by weight.
Emission factors are developed for each source category
on the basis of source performance test data, chemical
analyses of dusts recovered from control devices, industry
responses, material balances, and engineering judgment. The
data were obtained from current literature, private indivi-
duals, control agencies, and industry representatives. Most
emission factors given in this study should be considered
only as approximations, since they are based on limited
data. In many processes, lead emissions are a function of
the lead content of the charge or raw material; values for
lead content vary widely and are mostly unavailable.
2-42
-------
The annual lead emissions for each source category are
determined by multiplying the lead emission factor by the
1975 production (consumption) level and by the overall
average control factor for each source. Earlier efforts to
determine annual lead emissions by use of input from the
National Emission Data Systems (NEDS) for particulate emissions
yielded results of limited value; this method of calculation
was therefore abandoned.
Production rates given in this document are reliable.
The elements that remain questionable are the lead emission
factors and the overall control efficiencies: although
these data may not be fully reliable, they are the best that
are currently available. Collection efficiencies are assumed
to be essentially the same for lead as for total particulate,
except that some major lead emission sources have lead
-1-1 TO "I Q T /
concentrated in the fine particulate sizes. ' ' ' When
a smaller number of sources comprise a source category, as
in copper smelting, it is not difficult to estimate the
overall degree of control. When many sources are controlled
at various levels, as with power plants, the estimated
control levels are based on NEDS data and other published
information. A high degree of error may be prevalent with
respect to highly controlled industries. For example, if the
actual control level for the iron and steel industry is 99.5
2-43
-------
percent and the estimated level is 98 percent, an error of
400 percent would be involved in the estimate. Similarly,
if the actual control level of municipal incineration is 60
percent and it is estimated at 50 percent, the error would be
only 20 percent. These evaluations assume that the lead
emission factor is accurate.
The emission inventory presented is designed such that
as new and more reliable information becomes available, i.e.,
emission factors and control levels, these data can be incor-
porated to develop a more accurate inventory.
The uncontrolled lead emission factors, annual emission
estimates, and control techniques are given for each source in
Table 2-8. Table 2-9 presents a breakdown of lead emissions by
source category. Detailed discussion and references are given
in Chapter 3.0 and 4.0.
2.10 EMISSION TRENDS AND PROJECTIONS
An accurate projection of lead emissions to the atmosphere
in 1985 entails projection of changes in production and the
impacts of State and Federal regulations on new and existing
sources. The only significant reduction of emissions (65
percent) is attributed to the program for phaseout of leaded
gasoline additives. A much smaller reduction will be due to
additional control of air pollution from stationary sources.
The reduction of gasoline lead content from 0.45 to
0.13 g/1 (1.7 to 0.5 g/gal) by 197921 will reduce the lead
2-44
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2-49
-------
Table 2-9. RELATIVE CONTRIBUTION OF LEAD EMISSIONS
FROM ALL SOURCES
o of emissions
from source
of total lead
emissions
Mobile combustion
0 Leaded gasoline
Stationary combustion
0 Waste oil
0 Incineration
0 Coal
0 Oil
Industrial sources
0 Ferrous metals
and alloys
0 Primary nonferrous
metals
0 Lead additives
0 Secondary nonferrous
metals
0 Lead handling
operations
0 Miscellaneous sources
0 Lead oxides and
pigment
0 Battery manufacturing
100.00
76.95
18.00
3.51
1.54
24.4
32.6
14.1
11.3
8.5
6.4
1.6
1.1
90.4
4.6
5.0
2-50
-------
emissions from automotive sources from 128 Gg (140,900 tons)
in 1975 to 44.9 Gg (49,500 tons) in 1985, assuming a 2
percent per annum increase in average consumption.
The next largest decrease in lead emissions will be
from waste oil disposal. Although consumption of waste oil
22
for fuel will increase by over 42 percent by 1985 , the
lead content will decrease proportionately with gasoline
content, resulting in a decrease of lead emissions from 5.0
Gg (5,480 tons) in 1975 to 1.86 Gg (2,300 tons) in 1985.
A study of the emissions impact of new source per-
23
formance standards deals with industrial growth and
application of air pollution controls on most sources con-
sidered in this document. The report specifies emission
reductions anticipated by 1985 based on various assumptions.
In the calculation of 1985 emissions, these percentages of
reduction are multiplied by the annual emissions for each
source category. The results show that 3.7 Gg (4,038 tons)
of lead will be emitted by stationary combustion sources in
1985, compared to 6.50 Gg (7,143 tons) in 1975. Approxi-
mately 4.2 Gg of lead (4,650 tons) will be emitted in 1985
by industrial sources, compared to 7.1 Gg (7,800 tons) in
1975. The overall atmospheric lead emissions will be reduced
63 percent, from 141.4 Gg (155,840 tons) in 1975 to 52.8 Gg
(58,200 tons) in 1985.
2-51
-------
2.11 ANTICIPATED IMPACTS
The incremental impacts associated with an air quality
standard for lead are those impacts due to additional
emission control, beyond that required by a general state or
federal emission regulation, in order to meet the lead stan-
dard. The incremental impacts that may be incurred by indus-
try due to the NAAQS for lead cannot be estimated quantita-
tively. However the impacts associated with complying with
SIP particulate limits can be estimated and the relative
magnitude of the secondary environmental and energy impacts
due to additional control can be shown to be insignificant.
2.11.1 Plants Effected
The proposed lead air quality standards would affect
those plants which exceed the standard while complying with
SIP, NSPS, or other applicable regulations. It is inferred
that relatively few plants would require additional emission
reductions beyond that required by existing regulations. It
appears that the primary copper and lead smelting industries
would be most affected by a NAAQS for lead, primarily be-
cause of fugitive dust emissions. It is also reasonable to
state that not all plants in any one industrial category may
require emission cutbacks. For example, NAAQS for lead may
be exceeded around only 10 of the over 1500 gray iron
foundries after meeting all other emission limitations.
2-52
-------
This is due to such plant-specific variables as raw mate-
rial characteristics, production rates, state emission
regulations, meteorological conditions and/or geographical
location.
2.11.2 Pollutant Capture
Most plants which require even large emission reducticns
will need to collect relatively small amounts of emissions.
For example, a process meeting SIP limits by a control
system with a 90 percent efficiency may require up to 99
percent removal to meet NAAQS; this represents a decrease in
emissions by a factor of 10, but only a 10 percent increase
in pollutant catch. However, a process meeting SIP limits
by a control system with a 95 percent efficiency may require
only 98 percent removal to achieve NAAQS; this represents a
60 percent decrease in emissions but only 3 percent increase
in the amount of pollutant captured.
2.11.3 Solid Waste Impact
By the emission reductions, additional solid wastes
will be generated because of the increase in the amount of
pollutants collected. As shown above, this increase may be
only 3 to 10 percent for control of lead emissions. However
the total impact will usually be much less than 3 to 10
percent because solid wastes generated by air pollution
control equipment is usually a small fraction of that
2-53
-------
generated by the entire plant. If the total plant solid
wastes amount to only 10 times that for air pollution
control, the incremental impact of lead control may only be
0.3 to 1.0 percent. Furthermore, most solid wastes produced
by the processes considered herein can be recycled to the
process and, thereby, would present no impact on solid waste
disposal. In no case is a new type of solid waste created.
In some industries the collected materials must be disposed
of, usually in a landfill. None of these solid wastes
should be of a nature such that environmentally acceptable
disposal techniques are not available.
Consequently, the slight increases in solid waste
production are not expected to necessitate major capital
outlay for disposal facilities not already in operation
within the area of a plant.
2.11.4 Water Pollution Impacts
Most of the processes considered herein utilize dry
collection devices for particulate emissions. These are
advantageous because they greatly reduce or eliminate water
pollution poxential and the collected material is more
likely to be acceptable for recycle to the process.
In those processes where wet collectors are used for
emission control an increase in plant wastewater generation
will occur although this increase will not be significant in
2-54
-------
most cases. Moreover, to increase emission reduction to
achieve NAAQS for lead, the incremental impact on total
plant wastewater flow is even less. Normally, liquid-to-gas
ratios are maintained at 0.8 to 1.0 £*s /m -s (6 to 8
3
gpm/10 acfm) while only pressure drop is increased to
increase collector efficiency. Therefore there may be no
increase in wastewater production to reduce emissions
beyond SIP limits. Generally, about 10 percent of the
recirculated scrubber water is purged to control solids
buildup. This waste stream can be discharged to a municipal
sewerage system or recycled to processes with or without
treatment. Treatment facilities, if necessary, will generally
be available for other plant wastewaters or for wet collect-
ing devices used to meet SIP limits. If treatment facilities
are not available, wet scrubbers generating wastewaters
requiring extensive treatment may not be an economically
feasible alternative, and other control devices would be
used. In many industries, such as non-ferrous smelting,
huge quantities of wastewater are generated by the production
facilities and the wastewater contributed by air pollution
control devices is insignificant.
2.11.5 Energy Impacts
The incremental energy impacts for plants which require
emission control beyond that required to meet SIP limits
2-55
-------
will be most significant for wet scrubber applications. The
energy demand by air pollution control devices is generally
small in relation to energy demand for production, especially
in non-ferrous metals, iron and steel, and other industries
where vast quantities of energy are required. Where high
energy scrubbers are necessary to remove particulates from
high exhaust volumes, considerable energy is consumed. If
this is in a plant where process energy demands are relatively
low, then the energy impact of air pollution controls to
meet SIP limits could be significant. However, if energy
demands are so great other control alternatives would be
chosen if technically and economically feasible.
The additional energy required to control emissions
beyond SIP limits so as to achieve NAAQS for lead would be
insignificant for fabric filters and electrostatic precipi-
tators. For scrubber applications, the incremental energy
demand is a function of the gas flow rate and the required
increase in pressure drop. Below are approximate incremental
energy requirements as a function of additional pressure
drop:
2-56
-------
Additional Incremental energy
pressure drop required
kPa
1
2
3
4
5
Summary
in. WG
4
8
12
16
20
of Impacts
kJ/m3
6
11
17
22
28
Btu/103 acf
50
100
150
200
250
Promulgation of a national ambient air quality standard
for lead will apparently affect a relatively small number of
specific plants. Energy and environmental impacts associated
with achieving this standard are essentially negligible for
most situations. The impact of SIP controls are shown to
be small or negligible, for most cases, and that the impacts
of additional control is even less. The data presented in
this document relative to secondary impacts have been cal-
culated from assumptions and estimates with questionable
accuracy due to variability and lack of data. Therefore,
the secondary impacts due to SIP control are considered
order of magnitude estimates and are not to be considered
as averages or typical estimates. However, the approach
taken is sufficient to show that the incremental energy
and environmental impacts of achieving NAAQS for lead
should be negligible at the affected plants.
2-57
-------
2.12 EMERGENCY EPISODE PROCEDURES
Most states have adopted procedures to provide a mechanism
for rapid, short-term emission control to prevent accummulation
of air pollutants to hazardous levels under unfavorable
meteorological conditions.
At the time of writing, however, EPA believes that
there is no evidence that exposure to short-term (hourly)
u
peak lead levels in the ambient air have caused adverse
health effects in any segment of the general population,
although these conditions have not been studied specifically.
Therefore, an "emergency episode" for lead will remain
undefined until contradictory evidence is uncovered. For
this reason, EPA does not intend to require States to adopt
specific procedures to prevent lead emergency episodes as
part of their implementation plans.
2-58
-------
2.13 ReEerences
1. Ai.nual Preview 1975. U. S. Lead Industry. Lead
Industry Association, Inc. New York, N.Y. April
1976. 20p.
2. Lead Industry in May 1976. Mineral Industry Surveys.
U. S. Department of the Interior. Bureau of Mines.
Washington, D. C. August 5, 1976.
3. Grimley, W. Memo to Mr. George Crane (ESED). U. S.
Environmental Protection Agency. Emission Measurement
Branch. Research Triangle Park, N. C. November 18,
1976.
4. Crane, G. B. Control Techniques for Lead Air Emissions.
Draft. Environmental Protection Agency. Research
Triangle Park, N. C. February 1971.
5. Lead Storage Battery Manufacturers in the United States.
National Institute for Occupational Safety and Health.
Washington, D. C. October 29, 1976. (Unpublished).
6. Secondary Lead Smelters in the United States. National
Institute for Occupational Safety and Health. Washington,
D. C. (Unpublished).
7. Background Information in Support of the Development
of Performance Standards for the Lead Addivities Industry.
Interim Report No. 2. PEDCo-Environmental, Inc.
Cincinnati, Ohio. For Environmental Protection Agency,
Research Triangle Park, N. C. Contract No. 68-02-2085.
January 1976.
8. Primary Lead Production in December 1976. Mineral
Industries Surveys. U. S. Department of the Interior.
Bureau of Mines. Washington, D. C. February 16, 1977.
5 p.
9. Preferred Standards Path Analysis on Lead Emissions
From Stationary Sources. Emission Standards and
Engineering Division, U. S. Environmental Protection
Agency. Research Triangle Park, N. C. September 4,
1974.
10. Statmick, Robert M. Measurement of Sulfur Dioxide
and Particulate in a Copper Smelter Converter and
Roaster - Reverberatory Gas Streams. Environmental
Protection Agency. MERC, CSL (Draft Report). April
1974.
2-59
-------
11.
12.
13.
14.
15.
16.
17.
18.
19.
20.
21.
KaaKinen, J. W., R. W. Jordan, M. H. Lawasani, and
R. E. West. Trace Elements Behavior in Coal-Fired Power
Plants. Environmental Science and Technology. Volume
IX (9): 862-869. September 1975.
Lee Jr., R. E., H. L. Crist, A. E. Riley, and K. E.
MacLeod. Concentration and Size of Trace Metal Emissions
from a Power Plant, a Steel Plant, and a Cotton Gin.
Environmental Science and Technology. Volume IX (7):
643-647. July 1975.
Klein, D. H. et al. Pathways of Thirty-Seven Trace
Elements Through Coal-Fired Power Plants. Environmental
Science and Technology. Volume IX (10): 973-979.
October 1975.
Natusch, D. F. S. and C. A. Evans, Jr. Toxic Trace
Elements: Preferential Concentration in Respirable
Particles. Science. Volume 183: 202-204. January 1975.
Danielson, T. A. (ed.) Air Pollution Engineering Manual.
Los Angeles Air Pollution Control District. Environmental
Protection Agency. Research Triangle Park, N. C. AP-40.
May 1973.
Mcllvaine Scrubber Manual.
Illinois. 1974.
The Mcllvaine Co. Northbrook,
Billings, C. E. (ed.) Mcllvaine Fabric Filter Manual.
The Mcllvaine Company. Northbrook, Illinois. November
1975.
Nichols, G. B. (ed.) Electrostatic Precipitator Manual.
The Mcllvaine Company. Northbrook, Illinois. February
1976.
Control Techniques for Particulate Air Pollutants.
AP-51. U. S. Environmental Protection Agency. Office
of Air Programs. Research Triangle Park, N. C. January
1969. 215p.
Scrubber Handbook. Volume I. Ambient Purification
Technology, Inc. Riverside, Calif. For U. S. Environ-
mental Protection Agency, Control Systems Division.
August 1972.
Environmental Protection Agency Regulations on Fuels and
Fuel Additives. 40 CFR 42675. Part 80, Subpart B.
Sec. 80.20 (a) (1). September 28, 1976.
2-60
-------
22. Resource Recovery and Energy Roundup. Eight-Fold
Increases in Waste Oil Rerefined into Lubricating Oil
March-April 1976. 22p.
23. Hopper, T. G. and W. A. Marrone. Impact of New Source
Performance Standards on 1985 National Emissions from
Stationary Sources. Volume I. The Research Corporation
of New England. Wethersfield, Connecticut. U. S.
Environmental Protection Agency. Research Triangle
Park, N. C. Contract 68-02-1382. Task 3. October 24,
1975.
2-61
-------
3.0 COMBUSTION SOURCES
3.1 LEADED GASOLINE
Lead alkyl compounds were first added to gasoline in
1923 as a means of suppressing engine knock by promoting
uniform burning of the fuel-air mixture in the engine com-
bustion chambers.
Combustion in the cylinder of a gasoline-fueled engine
begins when a compressed charge of fuel and air is ignited
by a spark. A flame front moves through the mixture in all
directions from the point of ignition. The unburned gas
ahead of the flame front at any instant is called the end
gas. With proper operation, combustion proceeds as an
orderly chain reaction through the fuel-air mixture. Ex-
pansion of gases by the combustion causes the piston to move
and produce mechanical work.
Detonation, or knock, is the premature autoignition and
very rapid combustion of the fuel charge in the combustion
chamber. Detonation causes the occurrence of high-frequency
pressure waves in the combustion chamber and is accompanied
by very high rates of pressure rise. Detonating combustion
is audible as a sharp metallic rap, and it may cause damage
h
to engines. Energy is dissipated in the form of pressure
waves, heat, and vibrations. Higher rates of heat transfer
3-1
-------
to cylinder components cause overheating and reduce the lives
of valves, spark plugs, and pistons. Overheating of deposits
in the combustion chamber can cause knock-induced preignition.
The latter is a condition in which a "hot spot" in the com-
bustion chamber ignites the fuel-air mixture before the spark
plug fires. The resulting higher temperature and pressure
favor detonation of a larger portion of charge. Therefore,
detonation caused by using a fuel of insufficient antiknock
quality can result in a self-worsening situation that can
damage an engine if allowed to persist.
The octane requirements of a gasoline engine are expressed
as the minimum antiknock (or antidetonation) quality of the
fuel that will allow the engine to operate without knock
(or detonation) under "normal" conditions. The octane rating
of a fuel is estimated by comparing it to a blend of normal
heptane (of poor antiknock quality) and isooctane (of good
antiknock quality) that gives the same knock intensity in a
test engine under specific conditions. Two test conditions have
2
been specified for determing the octane rating of a fuel;
these are summarized in Table 3-1.
Table 3-1. OPERATING CONDITIONS FOR DETERMINING
OCTANE NUMBERS OF FUELS2
Factor
Charge- inlet temperature
Water- jacket temperature
Speed
Moisture, % wt
Research Method
52°C (125°F)
100°C (212°F)
600 rpm
0.36 - 0.72
Motor Method
149°C (300°F)
100°C (212°F)
900 rpm
0.36 - 0.72
3-2
-------
For determination of the Research Octane Number (RON)
[American Society for Testing and Materials (ASTM) designa-
tion D2699-68] a Cooperative Fuel Research (CFR) one-cylin-
der, variable-compression-ratio engine is operated at wide-
open throttle with the fuel to be tested, under the condi-
tions in Table 3-1. The compression ratio is adjusted to
give a standard level of knock intensity on a knock meter.
Then reference fuels, which consist of various blends of
normal heptane and isooctane, are run in the same engine
until a pair is found of which one will cause the engine (at
the same compression ratio) to have a slightly higher knock
intensity, and the other will cause a slightly lower knock
intensity than the fuel being evaluated. The fuel is then
bracketed, and its Research Octane Number (RON) is the
percentage of isooctane in the blend that would produce the
same knock intensity. The actual value is determined by
interpolation between the percentages of isooctane of the
two fuels that have been shown to bracket the fuel being
evaluated.
The Motor Method (ASTM designation D2700-68) is used to
determine the Motor Octane Number (MON). Although the
general procedure is the same, the specified operating
conditions of the engine at wide-open throttle are as shown
in Table 3-1.
The Motor Method provides a more severe test, because
the higher inlet temperature is more conducive to detona-
3-3
-------
tion. Because operating conditions in the Research Method
are less stringent, most commercial gasolines show a higher
octane rating by the Research Method than by the Motor
Method. The difference between Research and Motor ratings
is referred to as sensitivity. Thus, the sensitivity of a
fuel is defined as:
Sensitivity = RON - MOW
Paraffinic hydrocarbons generally have a very low
sensitivity. Olefinic and aromatic fuels, however, are
often quite sensitive. Because the severity of engine
operating conditions on the road is usually greater than the
severity of the RON test conditions, sensitive and insen-
sitive fuels of the same Research Octane Number may differ
greatly in performance on the road; i.e., the sensitive
fuels are much more prone to detonation. This is the reason
for the two test methods: together they predict the knock
behavior of fuels at road conditions better than either test
method alone.
Engine fuel octane requirements may be affected by
several engine design factors and operating conditions. A
major design factor is compression ratio. Compression ratio
is defined as the ratio between the gas volume in the
piston chamber of an engine when the piston is at the end of
the power stroke and the gas volume in the chamber when the
piston is at the point of maximum compression. As the
compression ratio increases, the maximum cycle temperature
3-4
-------
and maximum cycle pressure increase; hence, there is increased
tendency for detonation. The efficiency of gasoline-fueled
engines generally increases as the compression ratio increases.
In years prior to requirements for control of air pollutants
from motor vehicles, many automobile engines were designed
for use with the highest compression ratio compatible with
octane ratings of fuel supplies. With application of emissions
control technology in recent years, there has been a general
reduction in the compression ratios of automobile engines.
It has been reported recently that if pollutant emissions are
held constant there is no improvement in fuel economy with
3
increasing compression ratio. This is because of the tendency
toward gas heat loss and flame quenching at high compression
ratio, where the metal surface to gas ratio is larger than at
lower compression ratios. Cooler combustion increases unburned
hydrocarbons.
All internal combustion engines are equipped with some
type of cooling system. Generally, as the coolant temperature
increases, the end-gas temperature also increases and thus
increases the tendency for detonation. An improperly
functioning cooling system, such as one that is scaled
(impeding heat transfer), clogged (impeding flow), or not full
of coolant, can increase the octane requirement of the engine
by allowing increased temperature of the combustion chambers.
For best operation at normal speeds, the spark ignition
timing of most engines is so controlled that the electrical
spark that ignites the fuel-air mixture occurs before the
piston has compressed the mixture to its minimum volume.
3-5
-------
Such "spark advance" increases t.he efficiency r:-f ' :.c .--n
it also increases the peak cycle renaperatare and ;.-oroUie
and thus increases the tendency of the engine to detonate.
Engines using higher-octane fuel are generally adjusted for
greater spark advance than are those using low-octane fuel.
Moderate retardation of the spark from the best power setting
(i.e., timing the spark to occur later in the cycle) lowers
the octane requirement of an engine. Spark retardation
causes another phenomenon, however; because the charge is
ignited later, spark retardation causes a larger fraction of
the combustion heat to be rejected to the engine coolant
than would be the case with best power spark-advance con-
ditions. With a great deal of spark retardation, coolant
temperature may rise, especially at low speeds and heavy
loads.
The air-fuel ratio affects engine octane requirements.
Generally, air-fuel ratios near stoichiometric (between
14.5:1 and 15:1 air-to-fuel mass ratio) result in the high-
est octane requirement. Rich mixtures (between 12:1 and
13:1 air-to-fuel mass ratio) reduce the peak combustion
temperature and pressure and reduce octane requirement.
Combustion of very lean mixtures could theoretically reduce
peak combustion temperature and pressure and reduce octane
requirement because of the presence of excess air. In
conventional engines, however, difficulties sucr. as loss of
power, misfiring, and stalling, especially at j.eav,, loads
-------
where detonation most often occurs, preclude the use of very
lean mixtures (between 15:1 and 17:1 air-to-fuel mass ratio)
as a means of lowering octane requirement under heavy load
conditions.
Design of the combustion chamber influences the fuel
octane requirements of an engine. By virtue of design a
combustion chamber may contain "hot spots", such as an
exhaust valve or spark plug that does not cool well. Such
hot spots may cause preignition, with high peak combustion
temperature and pressure and increased detonation tendency.
Deposits of foreign matter that remain incandescent in the
combustion chamber can also cause preignition. Such de-
posits often consist of lead compounds derived from lead
alkyl antiknock fuel additives.
Motor gasoline is a complex mixture of relatively
volatile hydrocarbons obtained from the refining of petro-
leum. It ordinarily contains chemical additives of one kind
or another. Petroleum refining consists of a series of
processing, treating, and blending steps to convert mixtures
of crude oils of varying quality into gasoline and a wide
variety of other useful products. The type and amount of
each product depends on current demands. The largest
demand is for motor gasolines, which, in the United States,
accounts for about 45 percent of the total petroleum prod-
ucts. Modern refinery operations consist of a number of
basic processing steps, not all of which are necessarily
3-7
-------
found in all refineries. These operations include crude dis-
tillation, thermal cracking and visbreaking, catalytic cracking,
catalytic reforming, hydrogenation, alkylation, isomerization,
coking, and treating. Although each unit in the refinery per-
forms a specific function, the major emphasis is on producing
a high-quality motor gasoline.
To increase the octane number of gasoline and suppress
knock, antiknock agents are added to the fuel. Although a
number of chemical compounds can provide some antiknock
effectiveness, the most commonly used and the most cost-
effective are tetraethyl lead (TEL) and tetramethyl lead (TML).
An addition of about 0.8 g/1 TEL (3 g/gal) to catalytically
cracked gasoline will often provide an increase in octane
number of 5 to 7. In fact, the octane scale above 100 is
based on the amount of addition of lead to isooctane, as shown
in Table 3-2.
The relationship between gasoline lead content and octane
number is not linear. The initial increment of TEL is most
effective in increasing the antiknock quality of gasoline, and
the effectiveness of each succeeding increment is less. For
instance, if the TEL content of the premium gasoline shown in
Figure 3-1 were reduced from 0.8 to 0.5 g/liter (3.0 to 2.0
g/gal), the lead content of the gasoline would be reduced by
33.33 percent at the expense of about 1.4 RON, or 17 percent
of the total octane-number lead response.
-------
TEL LEAD CONTENT, g Pb/liter
0.10 0.20 0.30 0.40 0.50 0;60 0.70 0.80 0.90
84.0
0.0 0.5 1.0 1.5 2.0 2.5 3.0 3.5
TETRAETHYL LEAD CONTENT, g Pb/GAL.
Figure 3-1. Octane number versus lead content for gasolines
3-9
-------
Table 3-2. ASTM RATING SCALE FOR AUTOMOTIVE FUELS
ABOVE 100 OCTANE5
in
ppm
TEL
isooctane,
by volume^
0
132
264
396
528
661
793
Octane number
100
105.3
108.6
111.0
112.8
114.3
115.5
a 1.06 kg Pb/liter TEL (8.83 Ib Pb/gal TEL).
The effectiveness of the lead alkyls as antiknock
agents depends upon their ability to retard or suppress the
autoignition at high compression ratio. The mechanism
involved is not understood, even after much research. It is
believed, however, that the lead alkyl decomposes in the
engine cyclinder to form fine colloidal particles of lead
oxide. The particles then react with free radicals in the
hot, high-pressure gases ahead of the advancing flame front
and thus terminate chain reactions that lead to the forma-
tion of compounds (e.g./ peroxides) capable of lowering the
autoignition temperature of the unburned mixture. In essence
then, the lead alkyls suppress detonation or knock in spark-
ignited engines by promoting smooth combustion of the entire
>J.O
-------
batch of fuel-air mixture charged to the cylinder of an
engine and do not permit all of the mixture to explode
simultaneously. It is important to bear in mind that the
antiknock quality of gasoline is controlled primarily by the
chemical composition of the hydrocarbons in the gasoline,
and that the lead alkyls are used to supplement the anti-
knock quality achievable by varying the chemical composi-
tion. There are finite limits on the levels of antiknock
quality that can be reached by varying the nature of the
hydrocarbons contained in gasolines. In addition, there are
finite limits on the degree to which the antiknock quality
of gasolines can be improved by the inclusion of the lead
alkyls.
TEL is the most widely used antiknock agent, but tet-
ramethyl lead (TML) and mixtures of TEL and TML are being
used because they are more volatile than TEL and, therefore,
provide more even distribution of antiknock quality through-
out the gasoline boiling range. By distributing the anti-
knock action more evenly throughout the vaporizing fuel,
TEL-TML mixtures often provide superior antiknock perform-
ance in multicylinder carbureted engines.
Other knock suppressors include organic amines, such as
aniline, which are somewhat effective but higher in cost
than lead alkyls partly because of the large amounts re-
quired. Iron carbonyl is effective and relatively inexpen-
sive, but the combustion products are abrasive and cause
3-11
-------
accelerated engine wear. Some organic chemicals (e.g., tert-
butyl acetate) have shown a synergistic effect when added to
leaded gasoline. Such compounds give an increase in octane
number greater than would be expected from the individual
effects of the compound and the lead alkyl.
The nonleaded organometallic additive commanding greatest
interest at this time is methylcyclopentadienyl manganese
tricarbonyl (MMT). This compound has had commercial use as
a combustion improver for fuel oil and turbine fuel. Since
the 1960's it has had limited use in gasoline, usually in
o
combination with lead alkyls. In this latter use, 7.9 to
40 ing of manganese per liter of fuel (0.03 to 0.15 g/gal)
is reported to yield 2 to 4 research octane numbers in
selected fuels. Used without lead alkyls at a concentration
of 33 mg Mn/liter (0.125 g Mn/gal) (the recommended maximum),
MMT is reported to increase the road octane value of gasoline
about 2 numbers without adverse effects upon engine durability
Q
or engine exhaust oxidation catalysts. At a meeting with
EPA at Ann Arbor on January 20, 1977, General Motors reported
that the use of MMT increased hydrocarbon emissions and plugged
emission control catalysts.
3.1.1 Emissions
Factors that influence the emissions of lead from
combustion of gasoline in motor vehicles have changed in the
past decade. These factors are lower fuel octane and use of
catalytic converters. Lower fuel octane requirements are related
3-12
-------
to a decrease in average compression ratio in passenger car
engines, necessary to be compatible with the use of unleaded
gasoline. As depicted in Figure 3-2, the model-year-weighted
average compression ratio increased approximately 2-% numbers
from 1950 to 1969; it then decreased approximately 1-% numbers
to a weighted average value of 8.2 for the model years 1974
and later. ' Early in 1976 an official of General Motors
Corporation announced that there would be no increase in the
12
compression ratio of General Motors cars before 1985.
Figure 3-3 illustrates the changes in octane quality of
gasolines over the years due to both refining and lead
12
addition. The improvement achieved in recent years by lead
addition is substantially less than in early years. The
principal factor in octane quality today is refining, and
the role of lead has been gradually reduced. Between 1930 and
1970, the regular gasoline clear (nonleaded) pool increased
about 24 octane numbers, while the premium gasoline clear
(nonleaded) pool increased 34 octane numbers; these increases
have resulted from refinery operations. The incremental
increase for both premium and regular gasoline resulting from
the addition of lead alkyls has averaged about 7 octane numbers
over the past two or three decades.
With the decrease in the sales-weighted average com-
pression ratio for passenger car engines since 1970, the
number of passenger cars requiring premium gasoline has
decreased markedly. As a consequence, the demand for premium
3-13
-------
1950 1955 1960 1965
1970 1971
YEAR
1972 1973 1974 1975 1976
o
tt
5
z 10.0
o
H* Q n
4O
£ 8.0
§ 7.0
^ 6.0
COHPRESSION RATIO
j I I I I
I
I
I
1950 1955 1960 1965 1970
1971 1972 1973
YEAR
1974 1975 1976
Figure 3-2. Yearly trends of United States passenger car engine
design and gasoline antiknock quality. '
3-14
-------
100
80
rs
z
JJ
t-
u
o
60
O
RE:'*"!
r
/
i F
/"
JM G
^
An
/
\SOL;
/'/
^
f'T<;
/
/
RF
jS
fS'
F;' '
/ (CLEAR
f
1*1
i L:
. -'-
POOL)
80
70
60
RLC'JLAR GASOLINE
REFi.MNG
(CLEAR POOL)
1930 1940 1950 1960 1970
YEAR
Figure 3-3. Historical source of octane quality
commercial gasolines
3-15
-------
gasoline has declined correspondingly. These changes are
depicted in Figure 3-4. It is noteworthy that the clear
pool (unleaded) octane characteristics of premium fuel (see
Figure 3-3) is essentially that required as unleaded fuel
for automobiles equipped with catalytic emission control
systems. The decrease in demand for premium fuel has been
accompanied by an increase in demand for a lower-octane-
number unleaded fuel. This trade-off can be expected to
operate for only a few years, because, at its peak, the
demand for premium 'fuel was only about 40 percent of the
total passenger car market, while if the use of catalytic
emission control systems that require lead-free fuel should
continue, most passenger cars in operation a decade from now
will require unleaded fuel.
3.1.1.1 Quantity of Lead Emitted - Total domestic annual
demand for gasoline increased from about 238 Gl (6.3 x 10
gal) in 1960 to 390 Gl (1.04 x 1011 gal) in 1975.I! Con-
sumption decreased slightly from 1973 to 1974, the year of
the oil embargo by the Organization of Petroleum Exporting
Companies (OPEC). Annual gasoline demand for the years 1960
through 1975 is depicted in Figure 3-5. Over the past
decade, 70 to 75 percent of gasoline consumption is reported
to have been retail sales for use in passenger cars.
Use of lead in the domestic manufacture of lead alkyl
gasoline additives increased from about 149 Gg (164,000
tons) in 1960 to more than 252 Gg (278,000 tons) in 1970;
3-16
-------
avoy NO savo
HV3A 13QOW
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O
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CO
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-rH
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r \
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3-17
-------
o
LT>
co
WJL'QNVWBi] 3NI10SV9
c. o c
O Lf
CO CM
o
o
CM
rH
IT)
r-
cn
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4-1
rH
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SN011V9
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3-18
-------
use of lead for this purpose appears to have decreased since
1972. ' The annual consumption of lead in manufacture of
lead alkyls for the decade 1965 to 1975 is shown in Table
3-3.
Table 3-3. LEAD CONSUMPTION IN U.S. MANUFACTURE
OF LEAD ALKYL GASOLINE ADDITIVES15
Year
1965
1966
1967
1968
1969
1970
1971
1972
1973
1974
1975
Gg
204.28
223.94
224.21
237.57
245.94
252.60
239.66
252.45
248. 92
: 2 7 . 8 7
: P Q ~\ '
-' y 5 .
tons
225,203
246,879
247,170
261,897
271,128
278,505
264..204
278,304
274,410
251,210
/. 08,- 786
I \ 1958f as a result of a scudy by 3 cormnirr.er- estab-
lished a-t the request of the '." - S, Su-gecn Genera! . Lhe
recommended maximum amount of TEL in motor veh.tcle fuels was
set at 1057 ppm by volume (1,12 g Pb/iiter or 4,2? g Pb/gal)
In actual practice, this maximum lead content occurs in only
a small fraction of all gasolines.
If one assumes that all lead used in the domestic
manufacture of lead alkyls is for gasoline consumed in the
United States, (e.g., lead losses in the manufacturing
process are negligible, lead alkyl exports are negligible),
the data of Table 3-3 and Figure 3-5 may be used to estimate
the national average annual lead content of gasoline. Such
3-19
-------
an exercise yields annual average values of 0.74 to 0.79 g
Pb/liter (2.8 to 3.0 g Pb/gal) of gasoline for the years 1965
through 1970, and (2.4 to 2.6 g Pb/gal) for the years 1971 to
1973. A low value of 0.60 g/1 (2.26 g/gal) is obtained for
1974. A 0.58 g/liter (2.2 g/gal) is mentioned as being near
the national average of regular and premium fuels at that
21
time. For 1975, the calculations yield a lead content of
0.473 g/liter (1.79 g/gal). For the second quarter of 1976,
the lead content of the National gasoline pool actually was
i 70 i 40
1. 12 g/gal.
Nor all. lead contained in fuel is emitted in the exhaust
from a gasoline engirt; some is retained in the engine, in the
exhaust system, and in the crankcase oil. It was reported in
1969 that 70 to 80 percent of che lead in the gasoline is
eventually discharged in the exhaust. A later report, after
analysis of the literature, concludes that 75+4 percent of
lead in fuel is the appropriate factor for automobile exhaust
emissions in the Los Angeles basin. If one adopts the factor
75 percent of fuel lead as particulate lead emission in auto-
mobile exhaust, then average vehicle lead emissions from
vehicles can be estimated by use of data on national average
miles per gallon for automobiles and the lead content of the
national gasoline supply. Such estimates indicate that
average lead emissions from automobiles in the period 1971
through 1974 were 74 to 87 mg/km (0.12 to 0.14 g/mi).
Several reports have been made of measurements of
particulate lead emissions from test automobiles. One of
3-20
-------
21
these shows a weighted average particulate lead exhaust
emission rate of approximately 68 mg/km (0.11 g/mi) for three
1970 model Chevrolet automobiles using commercial gasoline
containing 0.58 g Pb/liter (2.2 g/gal) of fuel. The automobiles
were operated on a programmed chassis dynamometer according to
the Federal mileage accummulation schedule. Lead was collected
from exhausts with total exhaust filters over test distances
of 88.5, 45.1, and 33.8 Mm (55,000 mi, 28,000 mi, and 21,000 mi).
Gasoline consumption data are not reported. An assumed nominal
gasoline mileage of 5.9 km/liter (14 mi/gal), however, would
indicate exhaust emission of approximately 71 percent of the
lead in the fuel.
The national motor vehicle exhaust emissions of particulate
lead from the use of leaded gasoline can be estimated. Using
the amounts of lead consumed in the manufacture of lead alkyls,
an emission factor of 75 percent of fuel lead, and the assumption
that all gasoline engines behave similarly to passenger car
engines in the matter of lead emissions, one can calculate
that the mean national annual lead emission in motor vehicle
exhaust for the decade 1965 to 1974 was 191 Gg (210,000 tons).
A method based on total gasoline consumption and 1.7 g Pb/gal
in the gasoline pool has been used to calculate 1975 lead
/TO
emissions at 128 Gg (140,900 tons).
3-21
-------
Alkyl lead vapor is probably not a significant pollutant
from normal automobile operation. It can be evolved at sites
where alkyl lead is produced or used and can escape to atmosphere
18
through vents on the carburetor and fuel systems. Both TEL
and TML are light sensitive and undergo photochemical decom-
18
position in the atmosphere. Organic lead emissions have beer
3
identified and measured in the range of 5 to 5,000 yg/m
19 20
in automobile exhaust gases. ' These high values were
from a cold started, fully choked, and poorly tuned vehicle.
More representative values of organic lead have been measured
by an improved method for determining low organic lead concen-
c o Q
trations in air. Thus, concentrations of 0.04 to 0.11 yg/m
were found on streets, or about 0.3 to 2.6 percent of total
airborne lead. At busy service stations, about 3.9 to 9.7
percent of total airborne lead was organic lead.
3.1.1.2 Size Characteristics of Particulate Emissions
Many studies of the size characteristics of lead-bearing
particles in exhaust gases of engines using leaded fuels have
been conducted. It is clear that the quantities and size
distributions of such particles vary with fuel-use history
(i.e., the use of lead and other additives in fuels), mode
of operation of the engine, number of miles the vehicle has
been operated, history of maintenance and component replace-
ment of the vehicle exhaust system, exhaust gas temperature,
and probably other factors as well.
The size characteristics of exhaust particulates con-
taining lead from vehicles with conventional exhaust systems
3-22
-------
have recently been reported in connection with studies of
21
lead traps. Table 3-4 shows results of four test runs of
about 320 km (200 mi) each using gasoline containing 2.2
grams lead per gallon, the Federal Durability Driving
schedule on a programmed chassis dynamometer, and the
sampling method described
40 to 70 percent of the particulate lead emitted was in
particles having equivalent diameters less than 1 ym.
Overall these data yield a mass median equivalent diameter
less than 1 ym.
In studies of the influence of exhaust gas temperature
on particle characteristics, a mass median equivalent dia-
meter of about 0.15 ym was found for particles in diluted
room-temperature exhaust gases from combustion of leaded
23
fuel. About 80 percent on weight of the particles were
smaller than 1.7 ym; since essentially none were in the size
range 1.7 to 5.0 ym, the remaining 20 percent were of size
greater than 5 ym. The authors suggest that the particles
greater than 5 ym result from reentrainment of material
deposited in the exhaust system. The data reported were
obtained with a 5.74 liter (350 CID) engine operated on an
engine dynamometer at 25 m/s (55-mph) cruise conditions
using fuel containing 0.8 ml TEL/liter (800 ppm by volume).
Size distribution of particles in high-temperature
exhaust gases from combustion of both leaded and unleaded
24
fuels has been examined. The concentrations of particles
greater than 0.35 ym aerodynamic diameter were relatively
3-23
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low and approximately equal for unleaded and leaded fuels;
the concentration of particles less than 0.35 ym aerodynamic
size from leaded fuel far exceeded those of the same size
from unleaded fuel. The results are summarized in Table
3-5.
Table 3-5. DISTRIBUTION OF PARTICLE SIZES IN
EXHAUST AT 260°C (500°F) FROM LEADED AND UNLEADED FUEL.
5.74 Liter (350 CID) Engine At
25 M/S (55-MPH) Cruise Condition.
Fuels: Leaded Standard Regular And Indolene Clear
24
Unleaded fuel
Leaded fuel
Concentration of particles,
aerodynamic diameter
>0.35 ym
g/m3
1.6
1.7
gr/ft3
0.71
0.75
<0.35 ym
g/m3 1 gr/ft3
1.2
18.0
0.52
8.0
As the authors state, these results imply that lead com-
pounds exhausted as particulate matter are mostly in parti-
cles smaller than 0.35 ym aerodynamic diameter. It is
recognized that lead particles that deposit on the walls in
conventional exhaust systems occasionally flake off and
appear in the exhaust gases as particles of larger size.
The high-temperature samples described here were collected
from a special exhaust system by means of a high-temperature
Andersen stack sampler and glass fiber filters; the 5.74
liter (350 CID) engine was operated on an engine dynamometer
to simulate 25 m/s (55-mph) cruising road load.
3-25
-------
Size distributions were determined for particles in
engine exhaust gases in work done for the Environmental
25
Protection Agency by the Dow Chemical Company. The size
distributions of exhaust lead particulates were reported for
18 test runs, 15 of which were made with 5.74 liter (350
CID) engines on an engine dynamometer. Of these 15 runs, 12
simulated 30 m/s (60-mph) cruise and three were with the Dow
cycle. Two tests were run with 6.55 liter (400 CID) engines
on an engine dynamometer and one with a vehicle having a
5.74 liter (350 CID) engine and operated on a chassis dyna-
mometer; these three runs all simulated 30 m/s (60-mph)
steady-state operation. Engines were equipped with exhaust
pipe, conventional muffler, and tail pipe, and particle size
samples were obtained with Andersen samplers and filters
from an exhaust dilution system similar to that in reference
22. Hours of past operation or equivalent mileage for the
test engines and exhaust systems at the time of test are not
reported. Thirteen test runs were made with fuels containing
0.70 to 0.79 ml TEL/liter (700 to 790 ppm by volume); 11 of
these yielded mass median equivalent diameters of 0.1 ym or
smaller for lead particulates; the other two tests yielded
values of 0.35 and 2.0 ym. One test with 0.40 ml TEL/liter
(400 ppm by volume) gave a mass median equivalent diameter
of 3.1 ym for leaded particles. Fuels with no more than a
trace of TEL yielded mass median equivalent diameters of
0.1, 1.2, 1.35, and 1.5 ym for lead in four tests. These
data indicate that leaded fuels tend to generate lead
3-26
-------
exhaust particles having mass median equivalent diameters of
about 0.1 um or less under high-speed steady-state operating
conditions. One may suspect that under the conditions of
test described here relatively little lead particulate was
reentrained from exhaust system deposits.
*2 £.
Size distribution data have been reported for parti-
culate lead emitted from three production vehicles at various
mileages. Results are given in Table 3-6. Samples were
obtained over test runs of about 322 km (200 mi) each using
the dilution method of reference 22. Data for the first vehicle
listed in Table 3-6 (1966 Chevrolet) appear to be those
reported earlier in references 27 and 28 and used later to
illustrate the decrease in emissions of < 0.3 ym lead parti-
cles and the increase in > 9 um lead particles with increase
29
in vehicle mileage. This tendency is apparent also?
perhaps not quite so clearly, in data for the other two
vehicles. The differences in low-mileage (4.8 - 8.0 Mia,
3000-5000 mi) and high-mileage (26-88 Mm, 16,000-55,000 mi)
emissions of large lead particles (> 9 ym) are about a
factor of two, both in absolute rate and in percent of lead
emissions. The differences are less marked for small parti-
cles, those less than 1 ym; low-mileage emissions for this
series of tests were about 1.3 times greater than those for
higher mileages. Overall, the average values for all three
vehicles, regardless of mileage, suggest that about 40
3-27
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3-28
-------
percent of the lead particles emitted have equivalent dia-
meters greater than 9 ym, 40 percent less than 1 ym, and 20
percent between 1 and 9 urn. About 30 percent of the emitted
particles appear to have equivalent diameters less than 0.3
ym.
On the basis of tests with 1966 model automobiles with
stabilized exhaust deposits during the lifetime of a car
about 35 percent of the lead burned is emitted as fine
particles and about 40 percent as coarse. Fine particles
are identified generally as those having equivalent diameter
of about 0.5 urn and less; coarse particles are those with
equivalent diameter about 5 ym and greater. These investi-
gations showed very few particles in the range of 0.5 to 5,0
ym. The 26 test cars were operated on the seven-mode Fed-
eral cycle, and samples were obtained with a cyclone-filter
assembly attached directly to the tail pipe of the can lead
content of the fuel used for particle size samples was not
given, but, based on other investigations also described one
may speculate that the fuel contained about 0.8 ml TEL/liter
(800 ppm by volume). Federal cycle tests, weighted 35
percent cold and 65 percent hot, yielded fine-particle
emissions of 32 mg/km (0.051 g/mi) and coarse-particle
emissions of 17 mg/km (0.028 g/mi). These results agree
remarkably well with those reported in References 26 and 27
when one considers the differences in sampling technique and
vehicle operating mode.
3-29
-------
Early studies yielded markedly different results for
sizes of lead particles emitted from automobiles. For
example, one reported that for an average car with 53 Mm of
use (33,000 mi) about 25 percent of lead emissions were in
28
particles smaller than 1 ym. Another reported that 90
percent of weight of exhausted lead is contained in parti-
cles smaller than 0.5 ym. Such disagreement may be due to
many factors including the type of fuel used, the operating
mode or driving cycle, both the long-term and the immediate
past operating history of the exhaust system, and the
sampling and analytical methods.
Several conclusions about the size of lead particles
emitted by motor vehicles using leaded fuel can be drawn
from these investigations:
lo Most of the lead generated by engines burning
leaded fuel is in particles of submicron size,
with mass median equivalent diameters in the order
of < 0.1 to 0.3 ym.23,24,25
2. Lead compounds accumulate in crankcase oil and on
components of the engine and exhaust system. Over
the life of an automobile about 75 percent of the
lead in the fuel is emitted as particulate matter
in the exhaust.17,27,30
3. In general, 40 to 75 percent of the lead emitted
from production vehicles in typical operation
modes is in fine pari'-icles, ie., in particles
having equivalent dia.meter of less than 1 ym. 23,26,30
This suggests that, on' the average, 35 to 40
percent of lead in fue! is emitted as fine parti-
culate. About an equal amount (35 to 40 percent)
must then be emitted as coarse particles. The
emission rate of coarse particles is greatly
influenced by reentrainment of lead compounds that
3-30
-------
have been deposited in the exhaust and is highly
variable; fine particles are likely to be those
emitted directly from the engine and at a rate
more uniform than that of large-particle emission.
3.1.1.3 Composition of Particulate Emissions - When lead
alkyl compounds are burned, lead oxide is formed. This
compound has a high melting point and is almost nonvolatile
32
at combustion-chamber temperatures. To reduce the ten-
dency of lead oxide to build deposits in automobile engines,
commercial antiknock fluids include halogen compounds that
scavenge the lead deposits from the engine.- The most
commonly used commercial antiknock fluids contain =thylene
dicriloride and ethylene dibromide in a mclar rati" c c 2 ~o
le and in amounts required to react --rith all tne lead
present in the fluid.
The reason for adding ethyleie dihalides to TEL ": *
evident from the vapor pressure curves shown in Figura 3-6.
These curves show that the vapor pressures of lead halides
are much greater than those for lead and lead oxide; the
high volatility of the lead halides tends to carry such lead
compounds out of the power train. Lead removal is also
aided by the lower melting points of lead compounds similar
to those in engine exhausts. Melting points of several lead
compounds are shown in Table 3-7.
3-31
-------
TEMPERATURE, °C
600 800 1000 1200
1 x 10-
x 0
1 x 10
1 x 10
1 x 10
1 x 10
-3
1000 1500 2000 2500
TEMPERATURE,°F
Figure 3-6. Vapor pressure of lead compounds
3-32
-------
Table 3-7. MELTING POINTS OF SELECTED
LEAD COMPOUNDS34'35
Compound
PbBrCl
PbBr2
PbCl2
PbO-PbBr2
PbO-PbCl2
PbO
PbS02
Melting point,
°C
425-436
371
499
328-890
482-977
888
999-1093
°F
797-817
700
930
622-1634
900-1790
1630
1830-2000
The principal inorganic lead compound in the exhaust
from engines burning leaded fuel with halogen scavengers is
generally reported to be PbClBr.21'28'30'36 Table 3-8 shows
the reported composition of lead compounds recovered from a
lead trap from a vehicle operated on gasoline containing
0.58 g Pb/liter (2.2 g/gal). These compounds account for
about 84 percent of potential particulate lead exhaust
21
emissions from the vehicle.
3-33
-------
Table 3-8. COMPOSITION OF LEAD DEPOSITS
FROM A LEAD TRAP
Fuel: 0.58 g Pb/liter (2.2 g Pb/gal)
21
Compound
PbBrCl
PbS04
PbBr2
Pb3(po4)2
PbO
Total
Weight, %
54
19
11
3
13
100
Composition of lead particles emitted in engine exhaust
has been shown to be related to particle size. Studies of
emissions from vehicles operated on fuel containing 0.71 to
0.79 g Pb/liter (2.7 to 3 g Pb/gal) yielded a number of
findings including the following:
28
"Very large particles of greater than 200 microns have
a composition similar to exhaust system deposits con-
firming that they are reentrained or flaked material.
These particles contain approximately 60 to 65 percent
lead salts, 30-35 percent Fe203, and 2 to 3 percent
soot and carbonaceous material. The major lead salt is
PbBrCl with large amounts of PbO (15 to 17 percent)
occurring as 2 PbO-PbBrCl double salt. Lead sulfate
and lead phosphate account for 5 to 6 percent of these
deposits (low sulfur and low phosphorous fuel).
"PbBrCl is the major lead salt in particles of 2 to 10
microns equivalent diameter with 2 PbBrCl-NH.C1 present
as a minor constituent.
"Submicron lead salts are primarily 2 PbBrCl-NH.C1.
3-34
-------
"Lead halogen molar ratios in particles of less than 10
microns equivalent diameter indicate that much more
halogen is associated with these solids than the amount
expected from X-ray identification of 2 PbBrCl-NI^Cl.
This is particularly true for particles in the 2 to 0.5
micron size range.
"Only small quantities of 2 PbBrCl-Nt^Cl was found in
samples collected at the tail pipe from the hot exhaust
gas. Its formation, therefore, mainly takes place
during cooling and mixing of exhaust with ambient air."
These results agree generally with the earlier work reported
in reference 36 on the nature of particulate lead emissions
from motor vehicles.
Studies of exhaust lead particle composition as a
function of exhaust gas temperature from an engine using
fuel containing 0.79 ml TEL/liter (790 ppm of volume)
yielded somewhat different results; the principal lead
halide compound identified was PbCl2'PbClBr rather than
23
PbClBr. PbCl2'PbClBr was identified as the principal lead
component throughout the size spectrum (submicron to 10-20
Vim aerodynamic diameter) for samples of exhaust taken at
temperatures of 35°C (95°F) and 243°C (470°F); this compound
is not reported for samples taken at temperatures of 338°C
(640°F) samples. Lead-ammonium halides were not found in
samples taken directly from the engine exhaust stream; this
is consistent with the conclusion reported in reference 28
that formation of 2 PbBrCl-NH.C1 takes place mainly during
cooling and mixing of exhaust with ambient air.
3-35
-------
In summary, it can be concluded that lead halides are
the principal inorganic lead compounds emitted in the
exhaust of vehicles using leaded fuel with halide scavengers.
Lead-ammonium halides, although not emitted directly from
the engine, are a common constituent of exhaust gases after
dilution with ambient air. Lead oxhalides, lead oxides,
lead sulfates, and lead phosphates also result from use of
leaded fuels; these compounds are more likely to be found in
particles of larger size than in submicron particles.
3.1.2 Control Techniques
A direct means for controlling the quantity of lead
emitted from motor vehicles is to reduce or eliminate the
addition of lead antiknock compounds to gasoline. Another
means is to capture lead compounds from exhaust gases prior
to their release to the atmosphere from vehicles burning
leaded fuel. Other techniques also are available, including
the use of unleaded fuels other than gasoline and the use of
motive power units other than internal combustion engines.
Such techniques are discussed in AP-66, Control Techniques
for Carbon Monoxide, Nitrogen Oxide, and Hydrocarbon Emis-
sions from Mobile Sources.
3.1.2.1 Lead in Fuels - Section 211 of the Clean Air Act
provides that the Administrator of the Environmental Protec-
tion Agency may, by regulation, control or prohibit the
3-36
-------
manufacture or sale of any fuel or fuel additive for motor
vehicle use if any emission products of the fuel or additive
will (1) endanger public health or welfare, or (2) signifi-
cantly impair the performance of any emission control device
which is in general use or which would be in general use
with regulation of fuel or additive. Federal Regulations
controlling the lead content of gasoline have been promul-
39
gated under this authority. Regulations were promulgated
January 10, 1973, to ensure that lead-free gasoline would be
available to owners of automobiles equipped with catalytic
converters. The regulation required that gasoline stations
selling more than 757 m (200,000 gal) annually offer
unleaded gasoline by July 1, 1974; subsequent amendments
require availability of unleaded gasoline at smaller sta-
tions serving areas of low population density.
The most recent amendment to the Fuel Regulations
eliminates the interim phase-down levels prior to January 1,
1978 and the specified levels and effective dates as shown
in Table 3-9. The Environmental Protection Agency made
these amended regulations effective as of September 28,
1976.40
3-37
-------
Table 3-9. AMENDED FUEL ADDITIVE REGULATIONS AS OF
39 4f)
SEPTEMBER 28, 1976 '
Effective
January 1
January I
January 1
January 1
October 1
date
, 1975a
, 1976a
, 1977a
, 1978
, 1979
Maximum average lead
content,
g Pb/liter
0.45a
0.37a
0.26a
0.21
0.13
Pb/gal
(1.7)a
(1.4)a
(i.o)a
(0.8)
(0.5)
Eliminated, as amended on September 28, 1976.
Total gasoline use in the United States for the period
1960 through 1967 showed a remarkably uniform rate of
increase of 3 percent per year; for the period 1967 through
1973 use increased 4.9 percent per year. Consumption in
1974, the year of the OPEC embargo, was less than in 1973,
but that in 1975 was about 3 percent greater than in 1974.
Predictions of future gasoline use are uncertain. Over the
next decade, however, in the absence of major international
political interventions that would interrupt supplies, it is
reasonable to assume that the rate of increase in gasoline
use will be 0 to 5 percent per year.
The average lead content of motor gasoline in 1974 is
estimated to have been about 0.60 g/liter (2.26 g/gal). The
3-38
-------
summer 1976 pool average is estimated to be in the range
40
0.37 to 0.50 g Pb/liter (1.4 to 1.9 g Pb/gal); since lead
levels in gasoline for summer use are typically 0.05 to 0.08
g/liter (0.2 to 0.3 g/gal) greater than those for winter
use, the 1976 annual average may be lower than the summer
values, and not far from the 0.37 g/liter (1.4 g/gal) total
pool average sought by the regulations for 1976. Assuming
the time-phased reduction in the lead content of motor
gasoline at the levels for 1977 and later years, reduction
of total lead use from the 1974 estimated level would
result, as shown in Figure 3-7.
Automobile manufacturers have adopted catalytic reactor
systems as the means to meet regulations on emissions of
carbon monoxide, hydrocarbons, and oxides of nitrogen.
Catalysts currently available and in use for these systems
are adversely affected by lead in the fuel. As a result,
more than 75 percent of the 1975 model year and all of the
1976 model year automobiles produced in the United States
require nonleaded gasoline. As the number of vehicles that
require nonleaded gasoline increases, the amount of lead
used overall in the manufacture of gasoline will decrease.
Estimates of future use of motor vehicles based on reports
of past experience permit prediction of future lead use in
passenger car gasoline. Such predictions, based solely on
3-39
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use requirements for nonleaded fuel and neglecting any
effect of the time-phased reduction of lead in the total
gasoline pool, are depicted graphically in Figure 3-8.
These predictions are based on several assumptions:
1. Pre-1975 model automobiles will use fuel having
the 1974 average lead content.
2. 1975 and later model year automobiles will use
nonleaded fuel.
3. Future vehicle use patterns will be similar to
past experience with regard to annual miles of use
versus vehicle age^O and distribution of numbers
of vehicles in use by vehicle age.41
4. Average fuel economy by model year remains con-
stant.
It is recognized that these assumptions will not be
valid for the future; estimates based upon them, however,
provide insights into the nature of changes in lead use that
can be expected from the use of nonleaded gasoline. Note
that passenger vehicles consume 70 to 75 percent of all
gasoline.
Figure 3-8 entails fuel-use increases of 0 and 5 per-
cent per year over 1974 levels. Curves A-B represent fuel
lead use if all post-1974 model years continue to require
nonleaded fuel. Curves C-D represent the increase in lead
use that could occur if emissions control technology that is
tolerant of fuel lead should be adopted for all 1980 and
later model years and fuel lead at 1974 concentrations
should be used in these vehicles. The increases depicted in
3-41
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of a time-phased reduction in lead content of the total
gasoline pool.
Examination of Figures 3-7 and 3-8 assuming time-phased
reduction, suggests that the lead content in the total
gasoline pool will be the effective limit on use of lead in
gasoline until about 1982, even if all new vehicles should
require nonleaded gasoline. Should lead-tolerant emissions
control technology be adopted, regulation of the lead con-
tent of gasoline could continue to be the factor controlling
use of lead for this purpose even after 1982. The relative
effectiveness of fuel regulation is further emphasized by
the fact that it is applicable to the total gasoline pool
whereas the operational requirement for nonleaded fuel is
imposed only on those vehicles (currently light-duty vehicles)
requiring catalytic emissions control systems.
3.1.2.1 Gasoline Substitutes
Light hydrocarbon fuels have a high octane number
without lead and can be used for fuel in spark-ignited
internal combustion engines.
Table 3-10 compares the properties of compressed
natural gas (CNG), liquified natural gas (LNG), and liquified
petroleum gas (LPG) with those of gasoline. These
gasoline substitutes have the advantage of high octane
rating without lead; they also have excellent air-mixture-
distribution characteristics, offering a potential for lean
3-43
-------
engine operation and thus for a reduction in emissions.
These three fuels also involve special handling and ser-
vicing requirements that will limit their attractiveness for
use in captive fleets. The limited supply and the distribu-
tion problems are further impediments to their universal
use.
3.1.2.2 Particulate Collection Devices - Noble-metal
catalyst systems currently in use on new automobiles for
control of gaseous pollutants require nonleaded fuel. The
development and adoption of thermal converters, lead-tol-
erant catalysts, or other such means for satisfying emission
limits for gaseous pollutants, however, may make the use of
leaded fuels in future motor vehicles technically feasible.
Most of the lead emitted in exhaust streams from vehicles
using leaded gasoline is particulate; should lead-tolerant
emissions control systems be adopted, particulate collection
devices represent an alternative to regulation of lead in
fuels for the control of lead emissions from motor vehicles.
A number of approaches to particulate removal and their
applicabilities to engine exhaust systems have been ex-
plored. Such techniques include filtration, impingement,
agglomeration, adsorption, and thermal precipitation.
Collection devices should have the capacity to collect small
particles, i.e., those under 1 urn in diameter, and they
should require only simple and infrequent maintenance.
3-44
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Most reported work has been on inertial or impingement
type devices. One such device, reported to be relatively
simple, low in cost, and muffler-like in appearance was
43
described in 1970. Two parallel cyclone elements were
arranged to handle the exhaust in one element under light
load and in both elements under high load. A prototype was
road-tested for 57.9 Mm (36,000 mi) and reductions of up to
47 percent of exhaust lead were claimed. No information is
included on the reduction of particles smaller than 5 ym
when an improved unit was driven similarly for 38.6 Mm
(24,000 mi), reductions of 64 percent were claimed.
A more complex device consists of an interceptor in
conjunction with an inertial device. The interceptor
contains loose material for impingement and growth of
particles, which then migrate to the inertial device.
Reductions in exhaust lead of 70 to 90 percent are claimed,
but the performance for fine particles is not stated.
An Inter-Industry Emission control (IIEC) study of the
feasibility of protecting catalytic exhaust treatment equip-
ment by trapping lead close to the engine to conserve heat
for the catalytic oxidation reactors was also reported in
44
1970. In tests of a few hours, lead retention was as high
as 70 percent. In longer runs of up to 17.6 Mm (11,000 mi),
however, lead retention in the trap was poor. The traps
3-46
-------
were of the filter type; about ten filter materials were
tested, of which activated alumina was the most effective.
Higher filter temperatures favored lead retention. Potentially
serious problems were high filter back-pressure and high heat-
capacity effects of the filter assembly. The latter effect
increases the difficulty of maintaining gas temperature,
especially during cold starts. Insufficient work was done
to prove feasibility.
Since 1970 E. I. DuPont DeNemours and Company, Inc., has
developed and tested a muffler lead trap for motor vehicles
use. This device is illustrated in Figure 3-9. In tests
involving a variety of operating conditions and using fuels
with lead content ranging from 0.53 to 0.79 g/liter (2 to 3
g Pb/gal), this collector is reported to reduce total lead
emissions by 80 to 90 percent and air (suspendible) lead
01 / ^x
emissions by some 70 percent. ' One vehicle, operated in a
road test of 162.8 Mm (101,000 mi) with the lead trap, showed
a reduction of 83 percent in total lead emissions compared with
emission from a companion vehicle equipped with a conven-
tional muffler and operated over the same mileage; there was
no deterioration in performance of the lead trap with in-
21
creasing mileage. It is also reported that use of the
lead trap causes no adverse effect upon performance of
automobiles. Lead emissions from one vehicle, a 1970
Chevrolet with 5.74 liter (350 CID) engine, equipped with
3-47
-------
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3-48
-------
the DuPont lead trap, were measured by four different lab-
oratories (DuPont, Dow, Ethyl, Exxon) using the 1972 CVS,
1975 CVS, and seven-mode Federal Test cycles and gasoline
containing 0.58 to 0.71 g Pb/liter (2.2 to 2.7 g Pb/gal).
The results were remarkably consistent, with a test mean
emission rate of 12 mg Pb/km (0.019 g Pb/mi) and a range of
11 to 13 mg/km (0.017-0.021 g/mi) for the six tests re-
ported.
The Ethyl Corporation has developed an agglomerating
and inertial type device called the Tangential Anchored
Vortex Trap (TAV trap). This device is illustrated in
Figure 3-10. Tests of five vehicles equipped with the TAV
trap and operated in the range 9.7 to 80.5 Mm (6000 to
50,000 mi) (mean vehicle test mileage 38.9 Mm or 24,200 mi)
showed an average 78 percent reduction in lead emissions
relative to those of 11 vehicles with standard exhaust
46
systems operated an average of 44.7 test Mm (27,800 mi).
Emissions of total particulates, both lead and nonlead
compounds, were reduced by an average of 72 percent. Lead
emissions by size range for two TAV traps have been re-
ported; the reduction in emissions of particles greater than
0.4 ym mass median equivalent diameter was 83 percent, and
42
reduction in those less than 0.4 ym was 72 percent.
Since the overall reduction indicated by the size distribu-
tion test is greater than the mean value for the more ex-
3-49
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3-50
-------
tensive emissions road tests, the absolute values may be
questioned. The results suggest, however, that the device
is effective in collection of submicron as well as larger
particles. Tests of the unit with an additional final
filter stage showed emissions reductions of 93 to 94 percent
for total and airborne lead.
PPG Industries, Inc., has developed a motor vehicle
exhaust particulates collection device consisting of an
agglomerator, an inertial separator, and a fiberglass filter
unit. This system is illustrated in Figure 3-11. Reported
test results show lead emissions of 1 to 2 mg/km (0.002 to
0.004 g/mi), representing 93 to 96 percent reduction in
47
suspendable lead emissions. Lead emission values are
listed for nine test automobiles having a mean accumulated
mileage of 51.5 Mm (32,000 mi), mileage for individual
vehicles ranging from 8.05 to 80.5 Mm (5,000 to 50,000 mi).
The mileage accumulation schedule is not reported; the test
fuel, not reported either, is assumed to be commercial
leaded gasoline. It is reported that particulate removal
efficiency of the agglomerator-inertial separator unit when
47
used without the filter unit is 65 to 75 percent.
Laboratory studies have been done on the effectiveness
of thermal precipitation and sonic agglomeration in collec-
ting lead aerosols similar to those generated by spark
48
ignition engines using leaded fuels. Studies of thermal
3-51
-------
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deposition of lead chloride aerosol particles in the size
range of 0.1 to 0.8 ym showed that collection efficiency in
a packed bed depends primarily on the temperature differ-
ential between the gas and the packing. At a gas velocity
of 0.15 m/s (0.5 fps) through the bed, the efficiency of
collection exceeded 95 percent for temperature differentials
greater than 200°C (392°F). A gas velocity of 1.30 m/s (4.3
fps) yielded collection efficiencies 10 to 15 percent lower.
The efficiency of collection did not change appreciably with
changes in particle size or aerosol concentration. Studies
of sonic agglomeration revealed that travelling sound waves
are relatively ineffective in promoting collection of aero-
sol in a fluidized bed. Efficiency of a sonic fluidized bed
device approached 90 percent for collection of lead chloride
aerosol, however, when standing sound waves at a flux in
2 2
excess of 5000 W/m (465 W/ft ) were used. Specific use of
thermal precipitation or sonic agglomeration in practical
devices for control of particulate emissions from motor
vehicles has not been reported.
In summary, it is concluded that lead trap devices at
their presently reported stage of development are capable of
reducing overall particulate lead emissions from motor vehicles
by 85 to 95 percent and of reducing emissions of small lead
particles, those smaller than 1 ym, by about 70 percent. Lead
traps are not presently being installed by automobile manufac-
turers. Therefore, it is not warranted to discuss possible
environmental impacts by use of this control option.
3-53
-------
3.1.3 Control Costs
Costs attributable specifically to control of lead
emissions from motor vehicles cannot be identified at this
time. New automobiles use catalytic reactor systems for
control of emissions of gaseous pollutants; the catalysts do
not tolerate lead in the fuel. The use of nonBeaded fuel
eliminates emissions of lead in the exhaust stream, but
there is no basis for allocating a specific portion of any
incremental cost for nonleaded fuel to the control of lead
emissions. A comparison of total costs for control systems
using leaded fuel with costs for systems using nonleaded
fuel would provide a basis for estimating the increment of
cost related to control of lead emissions. Costs for
current new car systems that use nonleaded fuel can be
estimated, but there are no data on total system costs for
control of both gaseous pollutants and lead from vehicles
using leaded fuels.
It is possible, however, to examine costs for some
elements of overall emission control systems that affect the
emission of lead compounds. Such system elements may be
categorized as limitations on the use of lead additives in
fuels and use of mechanical devices to capture lead com-
pounds from motor vehicle exhaust streams.
3.1.3.1 Lead in Fuels - The benefits of adding lead alkyls
to gasoline to increase its octane rating are well known and
3-54
-------
generally agreed upon; the resultant higher allowable
compression ratios produce more power and better mileage for
a given size of engine. The extra power and mileage tend to
minimize crude oil consumption. The use of lead alkyls
allows greater flexibility in adjusting the refinery process
to obtain gasolines of acceptable octane number; ii addi-
tion, the use of lead is currently the cheapest way to
increase fuel octane rating by several octane numbers.
Another benefit should be mentioned: operation of pre-1975
cars on unleaded gasoline may result in excessive wear of
49
exhaust valves and valve seats. Valve seat wear tends to
be inhibited by deposits of lead or its compounds on valve
seats; these deposits act as a lubricant that separates the
valve and seat surfaces. With unleaded gasolines, valve
seat wear is most noticeable at high engine speeds and heavy
loads (high operating temperatures). Incipient welding
occurs, and small particles are torn from the valve seats.
The solution to this problem for cars designed for use of
nonleaded gasoline has been in valve design and in altered
materials of construction. Conversion in pre-1975 cars is
difficult and expensive. Fortunately, the amount of lead
required to prevent exhaust valve wear in such cars is quite
49
small; 0.13 g/liter (0.5 g/gal) will probably suffice.
3-55
-------
Also under study are fuel additives other than lead that
may be able to offset the potential valve seat problem.
The many implications of reducing or eliminating the
use of lead additives in gasoline have been extensively
debated. Many elements of cost that have been associated
with limiting the use of lead additives cannot be assigned
as costs for the control of lead emissions per se. The
demand for nonleaded gasoline for 1975 and 1976 model year
automobiles, for example, results directly from adoption
of catalytic emissions control systems that do not tolerate
lead in the fuel; a consequence, however, is the elimination
of lead emissions from such vehicles.
The technical and political factors that influence the
cost of motor vehicle fuel, and specifically the incremental
cost between leaded and nonleaded gasoline are extremely
complex and are not discussed in this document. A brief
examination of the incremental cost between leaded and
nonleaded gasoline is offered.
The first extensive study on costs of producing
unleaded gasoline was published in June 1967. The
American Petroleum Institute engaged Bonner and Moore of
Houston, Texas, to conduct an economic study, the primary
objective of which was to obtain data indicative of the
added cost of manufacturing unleaded gasoline. The study
was based on the situation in the United States and on the
3-56
-------
situation prevailing in the petroleum industry in the year
1965. The study was confined entirely to identifying the
added costs to the refiner of switching completely to the
manufacture of unleaded gasoline at a designated time while
maintaining -hen current octane levels in motor gasoline.
Increased capital and operating costs, based on the 1965
situation, were determined. The study was not intended to
encompass all costs that might be incurred by the petroleum
industry as a whole from the marketing of unleaded gasoline
or to examine the impact of such a move on the petrochemical
industry. This study indicated that the increase in overall
refinery costs for unleaded gasoline, based on an estimated
national average, was about 2.2 cents per gallon, with a net
increase in requirement of raw stock (crude) of about 5
percent. The total capital investment for the U.S. petro-
leum industry in new refinery equipment to enable production
of nonleaded gasoline was estimated to be 4.235 billion
dollars.
A later study by Bonner and Moore, based upon a dif-
ferent series of lead restriction schedules, yielded estimates
of 0.05 to 3.24 C/liter (0.2 to 0.9 C/gal) as the incremental
costs for production and marketing of nonleaded gasoline.
Using the figure 0.24 C/lb (0.9 C/gal) as the incremental
cost for production and marketing, and an additional cost of
1.0 C/liter (3.8 C/gal) for loss in efficiency due to the lower
3-57
-------
compression ratio of engines using nonleaded gasoline, the Ethyl
Corporation estimated that the incremental cost to consumers in
the year 1980 due to use of nonleaded rather than leaded gasoline
5 2
would be 1.3c/liter (4.8£/gal) (based on 1971 gasoline prices).
In 1974, the Environmental Protection Agency commissioned
a study to mathematically model the petroleum refining industry
in the United States and to predict up to 1985 the impacts on
the industry of the entry into the market of unleaded gasoline,
53
and the phase-down of total lead use in the gasoline pool.
It was assumed that unleaded gasoline would be manufactured
at about 92 RON and at an 84 MON minimum. It was assumed
that essentially all gasoline would be the unleaded grade in
1985, and an average product demand growth rate of two percent
per year was used. Investment was in 1975 dollars. The
additional 1985 refining cost, including capital charges and
manufacturing costs, was found to be 1.7 cents per gallon of
unleaded gasoline. On the same basis, the net energy penalty
to refining is 180,000 barrels per calendar day of fuel oil
equivalent.
In 1975 the National Academy of Engineering, in addres-
sing the matter of air quality and automobile emissions,
examined the relative costs of a variety of motor vehicle
emission control systems to achieve various limits for
emissions of gaseous pollutants. Although specific analysis
3-58
-------
of the incremental cost of nonleaded gasoline was not
reported, estimates of 0.13 and 0.53
-------
Table 3-11. ESTIMATED SALES-WEIGHTED FUEL ECONOMY
FOR AMERICAN-MADE AUTOMOBILES54
Manufacturer
American Motors
Chrysler
Ford
General Motors
km/liter (mi/gal) by model year
1974
6.97
5.87
6.30
5.10
(16.4)
(13.8)
(14.8)
(12.0)
1975
8.08
6.59
5.78
6.55
(19.0)
(15.5)
(13.6)
(15.4)
1976
7.78
6.98
7.36
7.06
(18.3)
(16.4)
(17.3)
(16.6)
Neither the incremental costs for nonleaded gasoline
nor the benefits of improved fuel economy in recent model
years can be assigned to the control of lead emissions from
motor vehicles. Unrelated though they may be, however, the
improvement in fuel economy far outweighs the incremental
cost for nonleaded fuel.
The EPA position on fuel economy of controlled automobiles
is summarized well in reference 55, Factors Affecting Auto-
motive Fuel Economy. Figure 32 of this reference charts a
comparison of 1975 models and pre-control models for all
vehicle weights. The comparison is made for individual makes
and models averaged in proportion to sales. The city driving
fuel economy for 1975 is equal to or better than that of the
pre-control models at all weights. It is also better than for
1974 models above 2,000 pounds. Thus, lowering of compression
ratio, in itself, has not reduced the fuel economy of late
model controlled cars.
3-60
-------
Other benefits related directly to use of nonleaded
fuel have been identified. The dependence of noble metal
catalytic emissions control systems on the use of nonleaded
fuel has been studied extensively. One recent report, which
cites a number of earlier reports, describes the separate
and combined effects of lead alkyls and the halide scav-
engers, ethylene dibromide and ethylene dichloride, on
platinum and palladium oxidation catalysts. Although
catalyst activity is not a simple function of the lead
deposit (it is influenced by the combination of additives),
the report reconfirms that TEL causes permanent deactivation
and irreversible loss of the Pt-Pd (platinum/paladium)
surface area. The choice of catalytic systems for control
of emissions of gaseous pollutants has made such control
dependent on nonleaded fuel; the utility of such systems is
identified as a major benefit of nonleaded fuels.
3-61
-------
Direct monetary benefits also accrue from use of
nonleaded fuels. The use of nonleaded fuel is reported to
increase spark plug life, to reduce carburetor maintenance,
and to reduce corrosion of engine components and exhaust
systems. Increased corrosion attributed to the use of
leaded gasoline is caused by the halogen-bearing scavengers
in the lead alkyl additive mix. One maintenance cost study
involves a 4-year test with a fleet of 24 automobiles
operated in city-suburban driving and a 5-year survey of
302 vehicles in consumer use. Matched pairs of auto-
mobiles were operated on leaded and nonleaded fuels over
periods up to 4 years, and the records of maintenance costs
were maintained. In this study gasoline-related main-
tenance costs increased with vehicle age and mileage. It
was concluded that over the lifetime of the average car
such maintenance costs averaged about 1.3 C/liter or 5c
less per gallon of fuel used for cars using nonleaded
gasoline than for those using leaded gasoline in the test
fleet, and about 1.1 C/liter or 4c less per gallon for
the nonleaded fuel cars in consumer use.
It is recognized that the lowering of compression ratio
to permit automobiles to operate on low octane nonleaded
gasoline entails a fuel economy penalty. EPA estimates this
58
penalty to be 5 percent. Given the requirement for emis-
sions control, it is concluded that this penalty may be
3-62
-------
offset by retuning of catalyst-equipped automobiles.
In addition, it is generally accepted that savings on main-
tenance that result from use of nonleaded rather than leaded
gasoline can be about equal to the fuel penalty, thus repre-
senting a net benefit for the use of nonleaded fuel.
In summary, a precise estimate of that fraction of any
direct or indirect costs associated with the use o- non-
leaded gasoline that may be attributed to control of lead
emissions cannot be made at this time. Given the require-
ment for control of emissions of gaseous pollutants, and a
trade-off between fuel economy decrement and reduced main-
tenance costs (neglecting fuel economy improvements from
better engine tuning), it is concluded that the cost for
control of lead emissions resulting from use of nonleaded
fuel is no more than a small (and undeterminable) fraction
of the incremental cost between unleaded and leaded fuel.
Any incremental cost increases for low-lead fuels which may
take place with implementation of time-phased reduction in
lead content of gasoline will be attributable to lead emis-
sions control. Any such costs should be less than the 0.13
to 0.63 £/liter (0.5 to 2.4 £/gal) increment predicted for
nonleaded fuel. Moreover, these costs are incurred to meet
the requirements of catalytic control systems and there-
fore, the true cost impact due to lead controls is not given
in this document.
3-63
-------
3.1.3.2 Collection Devices - Catalytic emissions control
systems now in use require the use of nonleaded fuel. The
development of lead-tolerant emissions control systems
capable of use with a significant fraction of new vehicles
could influence the long-range prospects for use of leaded
fuels. A great amount of interest in such systems is being
exhibited. ' ' ' The acceptance of lead-tolerant
emissions control systems could result in adoption of
exhaust lead collection devices for control of lead emis-
sions from motor vehicles.
The reported characteristics of several particulate
collection devices for trapping lead in automobile exhaust
were summarized earlier. Cost estimates for their devices
have been offered by three developers: DuPont, Ethyl, and
PPG Industries. These estimates are summarized here.
In 1972 DuPont estimated the cost of its production
prototype lead trap made to the exact outer dimensions of a
conventional muffler for a 1970 Chevrolet automobile with a
21
5.74 liter (350 CID) engine. Estimated consumer cost for
a retrofit trap was $36.00, compared with an estimate of
$17.30 for a conventional muffler. Consumer cost estimates
for a lifetime-type trap and lifetime conventional muffler
were $57.00 and $28.50, respectively. These estimated costs
agreed well with estimates obtained by DuPont from a muffler
manufacturer; both are summarized in Table 3-12. The report
3-64
-------
concludes that the cost differential for a lifetime muffler
and lifetime lead trap should not be so great as the $41.46
indicated by Table 3-12 if the trap is original equipment on
new vehicles. The amounts shown in Table 3-12 are for
purchase by an individual from an automobile parts jobber;
costs to a new vehicle manufacturer are expected to be
somewhat less.
As reported earlier, the DuPont lead trap has been
shown to reduce total lead emissions by 80 to 90 percent and
airborne lead emissions by about 70 percent.
Table 3-12. ESTIMATED COSTS OF DUPONT PRODUCTION
PROTOTYPE LEAD TRAPS21
Retrofit type trap
Manufacturing cost
Consumer cost
(from jobber)
Lifetime type trap
Manufacturing cost
Consumer cost
DuPont estimate
Conventional
muffler
$ 4.50
17.30
$ 7.50
28.50
Lead
trap
$ 9.36
36.00
$14.84
57.00
Manufacturer estimate
Conventional
muffler
$17.30
Lead
trap
$35.16
$69.96
The Tangential Anchored Vortex trap of the Ethyl Cor-
poration was reported in 1973 to have (for a device with
57.9 Mm (36,000-mi) life) a manufacturing cost of $6.30
3-65
-------
compared with $4.74 for a standard muffler. The comparable
manufacturing cost for the TAV device with filter unit was
reported to be $10.90. Table 3-13 lists these estimated
costs, along with the incremental cost for a consumer,
assuming a consumer-manufacturing cost ratio of 3:1, for
substituting a TAV trap for a conventional 57.9 Mm (36,000-
mi) muffler.
Tests of the TAV trap, as described earlier, showed, an
average reduction in lead emissions of about 8'1 percent,
and with the added filter stage about 93 percent.
Estimates of manufacturing and consumer costs for the
PPG Particulate Lead Trapping System are not available.
Estimates were reported in 1974, however, for the original
equipment sales prices for the PPG system and a conventional
muffler system. For the PPG device, fabricated or aluminized
steel, the estimated price of the agglomerator-inertial
separator unit was $8 and for the filter unit $13, giving a
total price of $21; a conventional muffler-resonator system
of the same material was estimated to cost $9. Fabrication
from low-grade stainless steel for 80.5 Mm (50,000 mi)
durability was estimated to increase the cost of the PPG
system to $36 and of the conventional system to $18. Emis-
sions reductions reported for the PPG system are 93 to 96
percent.
3-66
-------
Table 3-13. ESTIMATED COSTS FOR ETHYL TANGENTIAL ANCHORED
VORTEX (TAV) TRAP BASED ON 57.0 Mm (36,000-mi)
64
MUFFLER LIFE, 1973
Total manufacturing
cost
Incremental cost over
standard muffler
Incremental consumer
cost over standard
muffler
(assume markup 3:1)
Standard
muffler
$4.74
TAV
trap
$6.30
1.56
4.68
TAV trap
and filter
$10.90
6.16
18.48
The costs reported here suggest that for lead trap
systems capable of reducing particulate lead emissions by
about 90 percent, the incremental consumer cost over that
for a conventional muffler is about 0.03 £/km (0.05 C/mi).
An original equipment cost, or cost to a vehicle manufac-
turer to whom marketing economies may apply, may be somewhat
i 15,47
lower.
Should the use of lead traps become widespread, the
disposal of the devices after use would require attention.
Recognizing the ecological need to collect the lead from the
used devices, the DuPont Company conducted in 1973 a study
of the technical feasibility of collection and recycle of
21
the units. The study concluded that economically a
recycle program would just break even under the most
3-67
-------
favorable set of marketing conditions, including shortage
of materials and pressure for environmental concern.
In summary, it is concluded that if economically
advantageous lead-tolerant emissions control systems should
be developed, or if the retrofitting of pre-1975 automobiles
should be necessary for control of lead emissions, lead
trapping systems have the potential for reducing particulate
lead emissions in the order of 90 percent or more at
relatively modest cost.
Since lead collection devices are not currently installed
on automobiles by manufacturers, only limited data are avail-
able. Therefore, estimating secondary environmental impacts
and expanding discussion of this control option are not
warranted.
3-68
-------
3.1.4 References for Section 3.1
1. Gasoline and Other Motor Fuels. In: Kirk-Othmer
Encyclopedia of Chemical Technology. Vol. 10, 3rd
Edition, New York, John Wiley & Sons, Inc., 1966.
p. 467-481.
2. Taylor, C.F. The Internal Combustion Engine in Theory
and Practice, Volume 2. Cambridge, Massachusetts, The
MIT Press, 1968. p. 144.
3. Schweikert, J.E., et al. Emission Control With Lean
Mixtures. SAE Paper 760226. (Presented at the
Automotive Engineering Congress and Exposition. Detroit,
February 1976).
4. Air Quality Control Takes on a Major Role in Oil
Operations. Oil and Gas Journal. 68(24) :104, June 15,
1970.
5. ASTM Manual for Rating Motor Fuels by Research and Motor
Methods. 6th Edition. American Society for Testing
and Materials. Philadelphia, 1969. 194 p.
6. Lewis, B. and G. von Elbe. Combustion, Flames and
Explosion of Gases. New York, Academic Press, Inc.,
1961. 731 p.
7. Ter Harr, G.L. et al. Methylcyclopentadienyl Manganese
Tricarbonyl as an Antiknock: Composition and Fate of
Manganese Exhaust Products. Journal of the Air Pollu-
tion Control Association. 25 (8) :858-860 , August 1975.
8. Unzelman, G.H. Manganese Gains Stature as Octane
Improves for Unleaded Gasoline. The Oil and Gas
Journal. p. 49-57, November 17, 1975.
9. Manganese Gets Boost at SAE Meeting. The Oil and Gas
Journal. p. 28-29, October 20, 1975.
10. Brief Passenger Car Data 1969. The Ethyl Corporation,
New York. 1969. p. 9.
11. 1976 National Petroleum News Factbook Issue. National
Petroleum News. 68(5A), Mid-May 1976.
12. Refineries Get Good News from GM Auto-Emissions
Specialists. The Oil and Gas Journal. p. 54,
January 12, 1976.
3-69
-------
13. Allen, R.R., and C.G. Gerhold. Catalytic Converters
for New and Current (used) Vehicles. Universal Oil
Products Company. (Presented at the Meeting of West
Coast Section of the Air Pollution Control Association.
October 8-9, 1970).
14. Minerals Yearbook. U.S. Department of the Interior,
Bureau of Mines. Volumes 1961 through 1973. USGPO,
Washington, D.C. 1963 through 1975.
15. Annual Review 1975. U.S. Lead Industry. Lead Indus-
tries Association, Inc. New York, New York. 1975.
16. Logan, J.O. Universal Oil Products Company. (Testi-
mony to Assembly Committee on Transportation of the
California Legislature. Los Angeles. December 4, 1969)
17. Huntzicker, J.J., S.K. Friedlander, and C.I. Davidson.
Material Balance for Automobile-Emitted Lead in Los
Angeles Basin. Environmental Science and Technology.
9(5):448-457, May 1975.
18. Survey of Lead in the Atmosphere of Three Urban
Communities. U. S. Public Health Service, Washington,
D. C. Publication Mo. 799-AP-12, 1965.
19, Stoefan, D. Health Hazards Due to Lead in Gasoline -
A Warning from Sweden. Staedthehvgiene (Uelian/
Hamburg). 12:259-260, 1970.
20. Laveskog, A,, Organic Lead Compounds in Actomoti\re
Exhausts and in Street Air, Stockholm Cn.i varsity,
Institute of Analytical Chemistry, TPM-B1L-64. January
1971, 84 p.
21, Kunz, W.G., E.S. Jacobs, and A.J. Pahnke. Design and
Performance of Muffler Lead Traps for Vehicles,
(Paper presented to the Union Intersyridicale de 1'
Industrie du Petrole). Paris, France, January 1975.
22. Habibi, K. Characterization of Particulate Lead.
Vehicle Technology. 4(3):230-253, March 1970.
23. Ganley, J.T., and A.S. Springer. Physical and Chemical
Characteristics of Particulates in Spark Ignition
Engine Exhaust. Environmental Science and Technology.
8(4): 340-347, April 1974.
3-70
-------
24. Sampson, R.E., and A.f. jringer. Effect- of Exhaust
Gas Temperatr^-e a:id Fuel Coirposition on Particu] '-e
Emission from Spark Ignition Engines. Environme- ^al
Science and Technology. 7(1):55-60, January 1973.
25. Dow Chemical Company. Effect of Fuel Additives on the
Chemical and Physical Characteristics of Particulate
Emissions in Automotive Exhaust. U.S. Environmental
Protection Agency, Washington, D.C. EPA-R2-72-066.
December 1972.
26. Cantwell, E.N., et al. Control of Particulate Lead
Emissions from Automobiles. SAE paper 720672. (Pre-
sented at the National Automobiles Engineering Meeting.
Detroit. May 1972).
27. Habibi, K. Automotive Particulate Emissions and Their
Control. SAE paper 710638. (Presented at the Joint
Meeting of SAE Mid-Michigan Section and the American
Chemical Society Midland Section. Midland, Michigan.
October 1970) .
28. Habibi, K., et al. Characterization and Control of
Gaseous and Particulate Exhaust Emissions from Vehicles,
(Paper presented at the Air Pollution Control Associa-
tion, West Coast Division - Fifth Technical Meeting.
San Francisco. October 1970).
29. Habibi, K. Characterization of Particulate Matter in
Vehicle Exhaust. Environmental Science and Technology,
7(3) :223-234, March 1973.
30. Ter Haar, G.L., et al. Composition, Size, and Control
of Automotive Exhaust Particulates. Journal of the
Air Pollution Control Association. 22(l):39-46,
January 1972.
31. Lee, R.E. Jr., et al. Concentration and Particle Size
Distribution of Particulate Emissions in Automobile
Exhaust. Atmospheric Environment. Pergamon Press,
Oxford, England. 1970.
3-71
-------
32. Guthrie, V.B. Petroleum Products Handbook. New York,
McGraw-Hill Book Company, 1960. 864 p.
33. Peirrard, J.M. Photochemical Decomposition of Lead
Halides from Automobile Exhaust. Environmental Science
and Technology. 3(1):48. January 1969.
34. Kirk-Othmer Encyclopedia of Chemical Technology, Vol. 12
2nd edition. New York, John Wiley & Sons, Inc., 1967.
p. 270-279.
35. Calingaert, G., et al. Studies in the Lead Chloride-
Lead Bromide System. Journal of the American Chemical
Society. 71 (11):3709-3720, November 1949.
36. Hirschler, D.A., et al. Particulate Lead Compounds in
Automobile Exhaust Gas. Industrial and Engineering
Chem. 49(7) :1131-1142, July 1957.
37. Control Techniques for Carbon Monoxide, Nitrogen Oxide,
and Hydrocarbon Emissions from Mobile Sources. U.S.
DHEW, PHS, National Air Pollution Control Administra-
tion. Washington, D.C. NAPCA Publication Number
AP-66. March 1970.
38. 42 USC, The Clean Air Act, Amendments of 1970, 1857,
et seq., Sec. 211, (December 1970).
39. Federal Register, Regulations of Fuel and Fuel Addi-
tives, Part II. Environmental Protection Agency.
38(6):1254-1261, January 10, 1973, and Amendment,
Federal Register, 38(234) : 33734-33741, Part III,
December 6, 1973. (40CFR80).
40. Federal Register. Regulations of Fuels and Fuel Addi-
tives. Control of Lead Additives in Gasoline. Part
80. September 28, 1976. p. 42675.
41. Strate, H.E. Nationwide Personal Transportation Study -
Annual Miles of Automobile Travel. Report No. 2. U.S.
Department of Transportation. Federal Highway Admin-
istration. Washington, D.C. 1972.
42. 1975 Automobile Facts and Figures. Motor Vehicle
Manufacturers Association of the United States, Inc.
Detroit. 1975.
3-72
-------
17
43. Hirschler, D. A., and F. J. Marsee. Meeting Future
Automobile Emission Standards. AM-70-5. (Paper
presented at National Petroleum Refiners Association.
San Antonio, April 6-7, 1970).
44. Gray, D.S, Inter Industry Emission Control Program.
Lead Trap Feasibility Study. Report 11-1, American
Oil Comoany Research and Development Department, March
1970,
45 Evaluation of DuPont Lead Trap by EPA and DuPont.
Petroleum Laboratory. F,, 1 ">ai:>oril" De Nemours &
Coavoany, ~nc, VI lining! or;, >v '" JV/'TC f'LMR 5-7:.
Aujai1 : ",9/5
'.-( '.f.iiar50. 0 \, Scatus Report: - '"ir^Hijtial Anchored
''-'orreK rart1" culate Trao, Atlachnieni: 2. Letter to
Senator Randolph January 1974. In: Automotive ',ead
:;psi s.s'lops, Dart 2, p. ) 5. Hearings before the Panel on
tnv 1 ronmes;tal Science and Tecbr.ology of the Subcommittee
,n'i Kriviros .mental Pollution of the CorrtmLttee on Public
Works United States Senate. May 7 and 8, 19/4.
(Serial No. 93-H41).
47. Fremd, 0. Houston Chemical Company, a unit of PPG
Industries, Inc. In: Automotive Lead Emission, Part
1, p. 99. (Hearing before the Panel on Environmental
Science and Technology of the Subcommittee on Environ-
mental Pollution of the Committee on Public Works).
United States Senate. May 7 and 8, 1974. (Serial No.
93-H41).
48. Sood, S. K., and R. Karuhn. Development of Particulate
Emissions Control Techniques for Spark Ignition Engines.
Environmental Protection Agency. IIT Research Institute.
Report No. C6186-5. Chicago. February 1971.
49. Petrus, P. Mobile Oil Corporation. (Statement presented
to New York City Council re: Inter Industry Emission
Control Program. September 24, 1970).
50. Manufacture of Unleaded Gasoline. U. S. Motor Gasoline
Economics, Volume I. Houston. Bonner & Moore
Associates. June 1967.
51. An Economic Analysis of Proposed Regulations for Removal
of Lead Additives from Gasoline. Houston. Bonner & Moore
Associates. March 1972.
3-73
-------
52. Blanchard, L. E., and H. E. Hesselberg. Ethyl Corporation
Testimony - EPA Hearings on Proposed Lead Regulations.
Los Angeles, May 4, 1972. p. III6.
53. The Impact of Lead Additive Regulations on the Petroleum
Refining Industry: Volume I Project Summary. Arthur D.
Little, Inc. Cambridge, Mass. May 1976. Report to
Environmental Protection Agency, Research Triangle Park,
N. C. under Contract No. 68-02-1332. EPA publication
450/3-76-016a.
54. Automobile Emission Control - The Current Status and
Development Trends as of March 1976. (Report to the
Administrator of the Environmental Protection Agency,
Office of Mobile Source Air Pollution Control. April
1976).
55. Factors Affecting Automotive Fuel Economy. United
States Environmental Protection Agency, Office of Air
and Waste Management, Mobile Source Air Pollution Control,
Emission Control Technology Division. October 1976.
56. Otto, K., and C. N. Montreuil. Influence of Tetra-
ethyl Lead and Lead Scavengers on Oxidation of Carbon
Monoxide and Hydrocarbons Over Pt and Pd. Environmental
Science and Technology. 10(2): 154-158, February 1976,.
57, Gray, D. S., and A. G. Azhardi, Saving Maintenance
Dollars with Lead-Free Gasoline, SAE paper 720084,
(Presented at the Automobile Engineering Congress,
D e t r o it. . I a riu a r y 1 072).
!;S. I>t'c: -'1 jn of f:he A'"TTiii'".s i:
Envii orime'i ;;a 1 Procec ;~ ion
Suspension of 19~1 Motor
Chrysler Corporation. For:o Motor Cc rapapy,, anci -leneral
Motors Cor oo rat.-'0:1 Applicants, Washingto~: 0 C.,
March 5, 1975,
59. Adams, W. E., et al. Emissions, Fuel Economy and
Durability of Lean Burn Systems. SAE paper 760227.
(Presented at the Automotive Engineering Congress and
Exposition. Detroit. February 1976).
60. Herrin, R. J. Lean Thermal Reactor Performance - A
Screening Study. SAE 760319. (Presented at the Auto-
motive Engineering Congress and Exposition. Detroit.
February 1976).
3-74
-------
61. Pozniak, D. J. A Spark Ignition, Lean Homogeneous
Combustion Engine Emission Control System for a Small
Vehicle. SAE paper 760225. (Presented at the Automotive
Engineering Congress and Exposition, Detroit. February
1976).
62. Letter, David M. Augenstein, FEDCo-Environmental, to
George B. Crane, Environmental Protection Agency, Durham,
N. D., dated March 28, 1977,
63. Harrison, R. M. , R. Perry, and ~;, "[]. Slater
Contribution of Organic Lead wOnipoui.dt> to
Levels in Urban /. cmospheies . ni-. Inv^.rnacloKa i /.yniposiuni
Proceeding^, Recent; Advances in the Assessment 01 the
Health Effects of T;;i!"i^otJ:aent:dl Pollution,
Luxembourg, Comra. of f.uropean Coiiraualt: e^.
p. 178.}-1783.
64, Lenane, D, L. Letter to J. H. Somers, Envii orurern.al
Protection Agency, June 7, 19/3. Appendix C, letter to
Senator Randolph. January 1974. In: Automotive Lead
Emissions, Part 2, p, 424. (Hearings before the Panel
on Environmental Science and Technology of the Subcommittee
on Environmental Pollution of the Committee on Public
Works). United States Senate. Nay 7 and 8, 1974.
(Serial No. 93-H41).
3-75
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3.2 COAL, OIL, WASTE OIL, AND SOLID WASTE
Stationary combustion sources emitted an estimated 6.5
Gg of lead (7,143 tons) in 1975. The major contributors,
to be discussed in this section, were combustion of coal
228 Mg, 257 tons), oil (100 Mg, 110 tons), waste oil (5.0
Gg, 5,480 tons), and solid wastes (1.17 Gg, 1,296 tons)
Natural gas combustion does not generate lead emissions.
3.2.1 Coal Combustion
Most of the coal consumed in the United States is
burned in utility and industrial boilers. In 1975, com-
bustion in utility, industrial, and commercial and institu-
tional boilers consumed approximately 374, 49, and 3.6 Tg of
coal (412, 54, and 4 million tons) respectively. It was
estimated that 228 Mg (257 tons) of lead were emitted to the
atmosphere from the combustion of 426 Tg of coal (470 million
tons),
3.2.1 I raroc
-------
Cyclone firing represents less than 2 percent of the
total number of utility coal combustion systems. These
units burn coal in a horizontal cylinder, into which part of
the combustion air is introduced tangentially, imparting a
whirling or centrifugal motion to the coal. Molten ash is
discharged from the end of the cylinder.
Smokers are combustion units in which crushed coal is
burned c cc above a grate. The principal types of stok~_j
are spreader, vibrating grate, (as shown in Figure 3-i2.,,
anr traveling grate stokers.
Pialveri zed-coal firing is by far the most common method
of burning coal in utility and large industrial boilers.
These units burn an air suspension of pulverized coal in a
combustion chamber. They yield greater concentrations of
fly ash in a smaller size range than either stoker or cyclone
units. Figure 3-13 illustrates a pulverized-coal-fired
boiler system.
3.2.1.2 Emissions - Studies of the fly ash emitted from
coal combustion indicate that from 60 to 90 percent of the
lead in the coal is emitted as suspended particlate in the
234
flue gases leaving the boiler. ' ' The amount depends on
the properties of the coal, the operating conditions, and
the configuration of the boiler. Combustion temperature
influences lead emission rates. For example, the lead
content of bottom ash from a coal burned at 482°C (900°F)
3-77
-------
GRATE
Spreader stoker
GRATE TUYERE
BLOCKS
FLEXING
PLATES
COAL HOPPER-
COAL GATEi
OVERFI RE-AIR NOZZLES
Vibrating grate stoker
Figure 3-12. Spreader and vibrating grate stokers,
3-78
-------
WATER IN
VENT TO
ATMOSPHERE
ECONOMIZER
(PREHEATS
WATER) -
EMISSION
CONTROL
DEVICE
/.COAL-AIR
MIXTURE
INDUCED-
DRAFT FAN
.EORCED-
DRAFT FAN
PRIMARY
AIR
COAL
PULVERIZER
Figure 3-13. Pulverized-coal unit.
3-79
-------
was 10 times greater than in the ash from the same coal
burned at 982°C (1800°F).5
On a state-by-state basis, the average concentration of
lead in coal ranges from less than 1 ppm to over 33 ppm by
weight. Some coals have been known to contain over 250 ppm
lead. The weighted average lead content of United States
coal is approximately 8.3 ppm.
Assuming that 80 percent of the lead in coal is re-
leased in the fly ash, the emission factor of lead from coal
combustion systems can be expressed as 0.8 (L) g/Mg [1.6(D
lb/1000 ton], where L represents the lead concentration of
the coal in ppm. Based on 426 Tg of coal (470 million tons)
burned in 1975, the emission factor developed above, and 92
percent average particulate control efficiency, it was
estimated that 288 Mg of lead (257 tons) was emitted by coal
combustion facilities. Specific information on the
characteristics of lead emissions, such as particle size
distribution and resistivity, is sparse. Tables 3-14
and 3-15 summarize the typical characteristics of exhaust
gas from cyclone and pulverized-coal-fired boilers. In
addition, minor quantities of fugitive dust are emitted from
coal storage piles and from ash disposal operations.
3.2.1.3 Control Techniques - The primary method for control
of particulate emissions from coal-fired utility boilers is
use of the electrostatic precipitator (ESP). Mechanical
3-80
-------
Table 3-14. CHARACTERISTICS OF UNCONTROLLED EXHAUST GAS
FROM PULVERIZED-COAL-FIRED UTILITY BOILER
Parameters
Gas flow ratea
Temperature
Moisture content
Grain loading
Particle size
distribution^
Emission
factors
0 particulate6
0 leadf
0 sulfur
dioxide^
Standard
international
units
0.1-0.18
m3/s -kJhr
150°C
5-15% v
17-20 g/m3
60% < 10 ym
54% < 5 ym
17% < 1 ym
8A g/kg coal
0.8L g/Mg coal
19S g/kg coal
English
units
0.2-0.33
scfm/103
Btu per hr
300°F
5-15% v
7-8 gr/dscf
60% < 10 ym
54% < 5 ym
17% < 1 ym
17A Ib/ton coal
1.6L lb/103 ton
38S Ib/ton coal
References
9
9
9
9
9
8
2, 3, 4
8
Range of volumes correspond to 20-100% excess air.
Downstream from the air preheater. Upstream temperature is
about 370°C (700°F).
Depends on coal characteristics and boiler type.
After cyclonic precleaning.
A = ash content of coal, percent by weight; most coals
are 8-15% ash.
L = lead content of coal, ppm by weight; U.S. average is
8.3 ppm.
S = sulfur content of coal, percent by weight; most coals
are 0.5-3.5% sulfur.
3-81
-------
Table 3-15. CHARACTERISTICS OF UNCONTROLLED EXHAUST GAS
FROM CYCLONE COAL-FIRED BOILER
Parameters
Gas flow rate
Temperature
Moisture content
Grain loading0
Particle size
distribution
Emission
factors
0 particulate
0 lead6
0 sulfur
dioxide-^
Standard
international
units
0.1-0.18^
m /s*kJhr
150°C
5-15% v
1.2 g/m3
40-95%w. < 10 ym
20-75%w < 5 ym
1.5-5%w < 1 ym
1A g/kg coal
0 . 8L g/Mg coal
19S g/kg coal
English
units
0.2-0.33
scfm/103 Btu per
hour
300°F
5-15% v
0.5 gr/dscf
40-95%w. < 10 ym
20-75%w. < 5 ym
1.5-5%w < 1 ym
2A Ib/ton coal
1.6L lb/103 ton
38S Ib/ton coal
References
9
9
9
9
9
8
8
Range of volumes correspond to 20-100% excess air.
Downstream from the air preheater. Upstream temperature
is about 370°C (700°F).
Depends on coal characteristics and boiler type.
A = ash content of coal, percent by weight; most coals
are 8-15% ash.
L = lead content of coal, ppm by weight; U.S. average is
8.3 ppm.
S = sulfur content of coal, percent by weight; most coals
are 0.5-3.5% sulfur.
3-82
-------
collectors, fabric filters, and wet scrubbers are also used
to a lesser extent. Lead emission control devices as such
are not used on coal-fired boilers. However, conventional
particulate control will simultaneously reduce lead emissions
A. Mechanical collectors: Mechanical collectors, or multi-
clones, use a combination of centrifugal, inertial, and
gravitational forces to separate particles from the gas
stream; these units can achieve particulate collection
efficiencies of 70 to 90 percent, depending on particle
size. Since lead particle sizes are much smaller, a much
lower efficiency is expected for lead. They are widely used
on stoker-fired units and are used for precleaning ahead of
an electrostatic precipitator on some pulverized-coal-fired
units.
Q
B. Fabric filters: Fabric filtration has recently been
used successfully to achieve total particulate collection
efficiencies higher than 99 percent. Pulse-jet fabric
filters designed for superficial filter velocities of 2 to 3
cm/s (4 to 6 fpm) and reverse air filters at 1 to 4 cm/s (2
to 7 fpm) have been installed for particulate control.
n
These filter systems use fiberglass or Teflon bags and
operate at pressure drops of 1.0 to 1.7 kPa (4 to 7 in.
H20).
p
Registered trademark
3-83
-------
C. Electrostatic precipitators: To date, electrostatic
precipitators are used to a great extent to control partic-
ulate emissions from large boilers.
The size of ESP systems varies, depending upon flue gas
volume, particulate collection efficiency, and fly ash
characteristics. Larger-sized ESP systems are required for
higher efficiencies, greater gas volume, and more-difficult-
to-collect ash. The design efficiency of modern ESP systems
ranges between 95 and 99.7 percent, depending upon owner
policy and air pollution control requirements.
ESP systems are installed either before (hot side) or after
(cold side) the air preheater system. Combustion gas tem-
peratures ahead of the air preheater range from 315 to 480 C
(600 to 900°F). After the air preheater, gas temperature ranges
from 120 to 200°C (250 to 400°F). Economics and ash charac-
teristics determine whether a hot-side or cold-side ESP
system is selected. Some types of coal produce an ash which
can be collected much more easily on the hot side; although
the gas volumes are greater because of the higher temperature,
hot-side ESP systems are applied. Some ash can be collected
almost as easily on the cold side of the air preheater, and
in this case, cold-side ESP systems are applied. Often there
3-84
-------
are borderline cases where one ESP manufacturer will recom-
mend a hot-side ESP while another will recommend a cold-side
ESP as the most economical choice. For difficult-to-collect
ash, collecting-surface area to gas volume ratios for cold-
23-1
side, high-efficiency ESP systems are as much as 157 m /m -s
2 3
(800 ft /10 scfm). Hot-side precipitators with as much as
2 3 -1 2 3
69 m /m -s (350 ft /10 scfm) collecting-surface area have
been installed for high-efficiency, difficult-to-
collect ash applications. Figure 3-14 shows schematically
a typical cold-side ESP application on a utility boiler.
Table 3-16 presents flue gas and particulate data from two
examples of pulverized-coal-fired boilers equipped with
cold-side precipitators.
D. Wet scrubbers: High-energy venturi scrubbers offer
particulate control efficiencies of 99 percent or higher and
are generally used in conjunction with S0~ removal systems.
Pressure drops up to 6.2 kPa (25 in. H^O) are required to
meet emission regulations, depending on the particle size
and concentrations and other exhaust gas characteristics.
Variable-throat designs are used to maintain pressure drop
as the boiler load fluctuates. Corrosion potential and
maintenance requirements are high. Materials of construc-
tion consist of 316 L stainless steel used with alkaline
addition to the scrubbing water to maintain its pH above 3.
3-85
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-------
Fiberglass-reinforced polyester, rubber-lined steel, and
other corrosion-resistant materials can also be used.
12
3.2.1.4 Control Costs - Capital and annualized costs of
particulate control systems can vary significantly, depend-
ing on design efficiency and many site-specific factors.
Factors having a major impact upon costs are the size,
remaining life, and capacity factor of the plant; the sulfur
and ash content and heating value of the coal; the maximum
allowable particulate emission rate; and replacement power
requirements.
Figure 3-15 presents capital and annualized costs of
ESP's as a function of plant size. These costs are given
for existing plants at specified control levels and sulfur
contents for a capacity factor of 0.6.
Other assumptions are as follows:
Capacity,
MW
150
300
450
Heat rate,
J/kWh
10,550
10,000
9,800
(Btu/kWh)
(10,000)
(9,500)
(9,300)
0Flue gas rate,
m~Ys 'Mw
1.60
1.54
1.48
(acfm/MW)
(5,400)
(3,275)
(3,140)
Remaining
life, yr
10
15
20
Capital costs for new plant installations are 15 to 20
percent lower, and annualized costs, 20 to 30 percent
lower.
3-88
-------
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3.2.1.5 Impacts
A. Emission Reductions
Particulate emission reductions achieved by air pollu-
tion control equipment varies according to the type of
boiler and the ash content of the coal. The reduction for
pulverized coal-fired units, by far the most common type of
utility boiler, is about 8.4 A kg/Mg and (17 A Ib/ton) where
A is the ash content in percent by weight. Emission factors
for coal-fired boilers indicate the amount of emission
reduction and solid waste generated by particulate emission
control. The lead content of coal averages 8.3 ppm.
B. Energy Impact
Secondary fuel input (natural gas or oil) to coal-fired
boilers may amount to 5 percent of the heat input, or 1.2
GJ/Mg coal (1.2 MM Btu/ton) for coal with 2.6 MJ/kg (12,000
Btu/lb) heating value. For the ESP application about 0.017
GJ/Mg coal (0.017 MM Btu/ton) of electrical energy required
for a 0.8 kPa (3 in. WG) system pressure drop. For a wet
scrubber operating at 6 kPa (24 in. WG), 0.11 GJ/Mg coal
(0.11 MM Btu/ton) is required.
About 10 GJ/Mg coal (10 MM Btu/ton) of electrical
energy can be generated, assuming 30 percent conversion
efficiency, of which about 0.2 percent is required for ESP
operations and 1 percent is required for the wet collector
operation.
3-90
-------
C. Water Pollution Impact
Boiler feedwater blowdown is the major source of
wastewater at a utility boiler and amounts to approximately
5 percent of the total feedwater rate. This discharge
is estimated at 0.5 m /Mg coal (130 gal/ton). Essentially
no wastewater is generated by fabric filter or ESP appli-
cations. However, a wet scrubber may produce up to 1.2
m /Mg coal (300 gal/ton) of wastewater.
D. Solid Waste Impact
The volume of solid waste generated by air pollution
control devices depends on the type of boiler and coal
characteristics. For a pulverized coal-fired boiler,
the amount of solid waste generated can be 8.5 A kg/Mg coal
(17 A Ib/ton), where A is the ash content of the coal. The
solid waste (bottom ash) generated without emission control
is about 1000 A kg/Mg coal (2000 A Ib/ton).3 Therefore the
solid waste impact of emission control is less than 1 percent,
3-91
-------
3.2.2 Oil Combustion
Oil consumption in the United States in 1975 totalled
165 Mm3 (1.04 x 109 bbl) of distillate fuel oil and 177 Mm3
9 14
(1.12 x 10 bbl) of residual fuel oil. Total lead emis-
sions for all oil combustion sources are estimated at 100 Mg
(110 tons) in 1975.
3.2.2.1 Process Description - Oil combustion sources are
grouped in three major categories: (1) electric utility,
(2) industrial, and (3) commercial, institutional, and
residential units. A front-fired steam generator is shown
in Figure 3-16. Utility boilers generally emit less par-
ticulate matter per quantity of oil consumed than do the
smaller industrial and commercial boilers using the same
grade of fuel.
3.2.2.2 Emissions - Emissions from oil combustion depend on
the type of oil, the type and size of combustion equipment,
and the degree of combustion. Distillate oils contain less
lead than residual oil.
Typical particulate emission factors for oil-fired
3 3
combustion sources are: 1 kg/m (8 lb/10 gal) from power
3 3
plants, 2.75 kg/m (23 lb/10 gal) from industrial and
commercial plants using residual oil; and 1.8 kg/m (15
lb/10 gal) from industrial and commercial plants using
Q
distillate oil.
3-92
-------
INDUCED DRIFT
FIN
Figure 3-16. An oil front-fired power plant steam generator
(Courtesy of Babcock and Wilcox Co., New York)
3-93
-------
Typical characteristics of exhaust gas from oil-fired
boilers are shown in Table 3-17.
Concentrations of lead in residual oils range up to 1
ppm and in distillate oils from 0.1 to 0.5 ppm by weight. '
Emission tests of oil-fired boilers show that up to 60
percent of the lead in the fuel is emitted to the atmos-
phere. ' A general emission factor of 0.5 (P) g/m of
£
oil [4.2 (P) lb/10 gal] was developed where P is the lead
content of oil in ppm by weight, based on the emission of 50
percent of the lead in the fuel.
Totals of 165.3 Mm3 (1.04 x 109 bbl) of distillate fuel
oil and 177.4 Mm3 (1.116 x 109 bbl) of residual fuel oil
were consumed in 1975, accounting for 34 percent by volume
of the total refinery products. On the basis of 1974
consumption distribution, 13 and 9.8 Mm (81.8 and 61.8 MM
bbl) of distillate oils were consumed by power utilities and
industrial boilers, respectively. About 88.1 and 26.5 Mm
o
(5.54 and 1.67 10 bbl) of residual oil were fired in
14
utility and industrial boilers, respectively. The esti-
mated annual lead emissions from utility boilers burning
fuel oil were 45 Mg (50 tons), and from industrial boilers,
14 Mg (15 tons). These values were calculated assuming 0.1
ppm lead in distillate oil and 1.0 ppm in residual oil.
With the combustion of 343 Mm3 (2.156 x 109 bbl) of dis-
tillate and residual oils from all sources, including home
3-94
-------
Table 3-17. CHARACTERISTICS OF UNCONTROLLED EXHAUST
GAS FROM OIL-FIRED BOILERS
Parameters
Fuel consumption
Gas flow rate
Temperature
Moisture content
Grain loading
Particle size
distribution
Emission
factors
0 particulars
0 leadc
Standard
international
units
0.26 liter/kW
19 km /m of oil
150°C
9-11% v
< 0.07 g/m
87% w < 1 urn
7.3% w < 2 yra
3.0% w < 5 ym
1.0-2.8 kg/m°
oil
-,
0.5(P) g/mj
oil
English
units
0.070 gal/kW
2500 acf/gal
300°F
9-11% v
< 0.03 gr/dscf
87% w < 1 ym
7.3% w < 2 ym
3.0% w < 5 y.m
8.0-23 lb/1'000
gal oil
4.2(P) lb/106
gal
References
7
7
7
7
7
7
CE
17, 18
After air preheater.
Depends upon oil and boiler type.
P = lead content of oil, ppm by weight.
3-95
-------
heating, railroads, and trucking, a total lead emission of
100 Mg (110 tons) of lead is estimated on the basis of the
above assumptions.
In an analysis of 100 crude oils produced in the United
19
States, the average lead content was 0.29 ppm.
Emissions of lead from oil consumption, considered in
terms of both nationwide and point-source emissions, are
comparatively small. A typical medium-sized (300 MW) power
plant boiler will consume 71.5 m (450 bbl) of fuel oil per
36 7
hour and exhaust 470 m /s (10 cfm) of combustion products.
If lead content of the oil were a very high 5 ppm, the lead
emission rate would amount to only 0.04 g/s (0.33 Ib/hr) or
88 yg/m3 (3.8 x 10~5 gr/acf).
3.2.2.3 Control Techniques - Emission control devices are
not generally used on oil-fired boilers since particulate
regulations can be met by proper design, operation, and
maintenance of firing equipment.
Precipitators and fabric filter systems could be used
to control particulate emissions, as well as lead, up to 99
percent efficiency or higher. Lead emissions can also be
reduced by utilizing low-lead fuel.
3.2.2.4 Control Costs - Since it may not be necessary to
require an air pollution control device for oil-fired sources,
no control costs are given.
3-96
-------
3.2.3 Solid Waste Incineration
An average of 1.6 kg (3.5 Ib) of domestic refuse and
garbage is collected per capita per day in the United
States. Excluded from this estimate are wastes such as
demolition and construction wastes, street sweepings, sewage
sludge, and residuals from mining, agricultural, and in-
dustrial activities. Incineration of wastes as a means of
volume reduction is a common practice in metropolitan areas.
In 1975, approximately 16.5 Tg (18.2 x 10 tons) of waste
21
was burned in a wide variety of municipal incinerators.
Possible sources of lead in the waste are solder from tin
cans, lead foils, collapsible tubes, lead toys, and crank-
case oils. Quantitative data on the lead content of the
waste are not available, but based on limited emissions test
data, the 1975 lead emissions from municipal incinerators
are estimated at 1.17 Gg (1296 tons).
3.2.3.1 Process Description - Most incinerators consist of
a refractory-lined chamber in which refuse is burned on a
grate. To achieve more complete combustion, most municipal
incinerators incorporate a secondary chamber where gas-phase
combustion takes place. The burning mechanism is one of
fuel-bed surface combustion. This is attained by the
predominant use of overfire combustion air and by charging
the incinerator in such a manner as to provide concurrent
travel of both air and refuse with minimum admission of
3-97
-------
underfire combustion air. Charging of the waste in the
primary chamber is thus an important aspect of proper oper-
ation. Auxiliary fuel is usually required to initially ig-
nite the waste.
Gases from the secondary chamber either discharge
directly through a stack or pass through one or more air
pollution control devices before discharge to the atmos-
phere.
3.2.3.2 Emissions - Incineration generates both gaseous and
particulate emissions. Operating conditions, refuse com-
position, and incinerator design have a pronounced effect on
the emissions. Particulate emissions are most affected by
the manner in which combustion air is supplied to the com-
bustion chamber(s), the method of charging, and ash removal.
Figure 3-17 shows a cross-section of a typical municipal
incinerator with a gas cooler and precipitator.
Lead is emitted in the form of particulates. For con-
trol of these emissions it is important to limit the ad-
mission of underfire air and thereby maintain relatively low
fuel bed temperature. With a relatively high rate of air
flow through the fuel bed, the stack effluent contains
appreciable quantities of metallic salts and oxides in
microcrystalline form. A probable explanation is that
vapor-phase reactions and vaporization of metals take place
at high fuel-bed temperatures, with resultant condensation
3-98
-------
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3-99
-------
of particles in the effluent gases as they cool upon leaving
22
the stack.
Although very limited lead emission test data are
available, several tests indicate that lead emissions range
from 0.015 to 0.25 g/kg of charge (0.03 to 0.5 Ib/ton).
Since adequate data on process conditions and waste lead
content are not available, no conclusions can be made about
the relative effects of these variables. A recent study
indicates that 95 percent of the lead particles are smaller
than 3 microns diameter, and 60 percent smaller than 1
22
micron. Typical exhaust gas parameters are given in Table
3-18.
On the basis of emissions data in references 15, 22
and 23, uncontrolled lead emissions from municipal inciner-
ators are estimated to be 0.2 g/kg of charge (0.4 Ib/ton).
1 21
Assuming an overall control efficiency of 64 percent, '
the lead emissions from municipal incinerators in 1975 are
estimated to be 1.17 Gg (1296 tons).
3.2.3.3 Control Techniques - Proper design and operation
are the most effective means of minimizing particulate
emissions from incinerators. A modern, well-designed,
municipal incinerator, however, cannot meet Federal and
state regulations for particulate emissions without a con-
trol device. To attain these standards, almost all par-
ticles larger than 1 to 3 microns must be removed. This
requirement eliminates the traditional sole use of low-
3-100
-------
Table 3-18. CHARACTERISTICS OF UNCONTROLLED EXHAUST
GAS FROM MUNICIPAL INCINERATORS
Parameters
Gas flow rate
Temperature
Grain loading
Particulate sizeC
distribution
Lead size
distribution
Emission
factors
0 particulate
° leadd
Standard
international
units
6.25 m3/kg
charge3
3.75 m3/kg
charge*3
315-370°C
0.7-2.3 g/m3
70% < 60 ym
42% < 20 ym
18% < 10 ym
12% < 5 ym
95% < 3 ym
60% < 1 ym
8 . 5 g/kg
charge
0.2 g/kg
charge
English
units
100 scf/lb
charge
60 scf/lb
charge
600-700°F
0.3-1.0 gr/dscf
70% < 60 ym
42% < 20 ym
18% < 10 ym
12% < 5 ym
95% < 3 ym
60% < 1 ym
17 Ib/ton
charge
0.4 Ib/ton
charge
References
7, 9
7, 9
7, 9
22
8
15, 22, 23
d
200% excess air, refractory-lined furnace.
80% excess air, water-wall furnace.
Obtained from a major air pollution control equipment
manufacturer.
Fifty percent or more of the lead in the charge may be
emitted in the exhaust gas.
3-101
-------
efficiency control devices such as baffled chambers and
spray towers and necessitates the use of electrostatic
precipitators, wet scrubbers, or rarely, fabric filter
systems. These devices can collect a substantial amount of
lead if they are designed to collect submicron particles.
Since vaporization of metallic salts and oxides and sub-
sequent condensation of these vapors may be a probable cause
of lead emissions, these emissions may also be reduced by
limiting the admission of underfire air and thereby con-
trolling fuel bed temperatures.
Segregation of waste before combustion can be utilized
to remove metal components and thus reduce potential lead
emissions. Alternatively, switching from incineration to a
landfill for disposing of solid waste will eliminate lead
emissions.
Selection of a specific control technique depends on
such factors as the available space and waste disposal
facilities, the control efficiency requirement, initial
system cost, operating cost, reliability, incinerator's age,
and land availability for a landfill.
A. Gas Cooling; Depending on the furnace type, temper-
atures of the gases leaving the furnace range from 426 to
1090°C (800 to 2000°F). Cooling is required prior to in-
troduction of these gases to a baghouse or a precipitator,
and also, in view of rising costs of materials, before a
scrubber.
3-102
-------
For baghouses and precipitators, the primary require-
ment is complete evaporation of the water in the cooling
chamber, with no moisture carryover. Otherwise, the dust
will tend to cake or form a slurry.
The interior of the the spray cooling chamber is
equipped with refractory lining, as is the ductwork leading
from the incinerator furnace. In addition, titanium, Haste-
alloy alloy C-276, and Inconel alloy 625 have shown satis-
factory test performance. Since the control device and fan
can be damaged by exposure to high temperatures, provision
should be made to bypass the gases around the control device
in case of failure of the water supply or other components
of the system.
24
B. Wet Collectors: Incinerator stack gases contain
gases such as hydrogen chloride that dissolve during scrub-
bing and cause the water to become acidic. Because of this,
even stainless steel scrubbers have been known to corrode.
Therefore, steel-lined scrubbers are used and pH of the
scrubbing solution is controlled by the addition of alkali.
3
To achieve an emission rate of 50 mg/m (0.02 gr/scf),
venturi scrubbers with pressure drops as high as 12 to 15
kPa (50 to 60 in. H2O) may be required. Selection of the
pressure requirement for a scrubber is extremely difficult
because of variations in particulate loading and size
distribution. Wastewater from the scrubbers can be used
3-103
-------
to quench the furnace residue prior to treatment or dis-
posal, thereby reducing both water and treatment costs.
C. Baghouses: Only a few baghouses have been built for
control of emissions from municipal incinerators. The lack
of use may be due to the sensitivity of filters to high and
low temperatures, space requirements, rapid fouling of
filters by condensation of fats, and significant operating
24
costs. Most fabric filter installations have used sili-
conized fiberglass bags. Cleaning is done by intermittent
shaking, reverse air, pulse-jet, and combinations of these
methods. Typical superficial filter velocities are 1 to 2
cm/s (2 to 4 fpm) with corresponding pressure drops of 1 to
2 kPa (4 to 8 in H2O).9
D. Electrostatic Precipitators; Although used extensively
in Europe, electrostatic precipitators were not used on
incinerators in the U.S. until 1969. Almost all new incin-
erators built since 1969 are equipped with electrostatic
precipitators for particulate emission control. Figure 3-17
shows an ESP applied to an incinerator. Design efficiencies
24
of these precipitators range from 93 to 97.5 percent.
Reported values of precipitation rate parameter, or drift
velocity, are 4 to 10 cm/s (0.13 to 0.33 fps). Table
3-19 presents design parameters for precipitators recently
applied to incinerators.
?-104
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Corrosion resulting from acidic gases can be a problem
in precipitator operation. This problem can be overcome by
maintaining gas temperature above the dewpoint, with proper
insulation and hot-air purging during startup and shutdown.
The primary material of construction has been mild steel.
To prevent accelerated deterioration due to condensation of
acid gas, castings of Corten steel have also been used.
3.2.3.4 Control Costs - A refractory-lined municipal incin-
erator with a capacity of 227 Mg/day (250 TPD) is considered
a typical model plant for the emission control cost anal-
ysis. Exhaust flow from this type and size of incinerator
is 70 m3/s at 980°C (148,000 acfm at 1800°F).7'9 Emissions
are 80 kg/h (177 Ib/hr) particulate and 1.9 kg/h (4.2 Ib/hr)
lead. These gases are cooled by a spray chamber to 315°C
(600°F) before they enter an insulated electrostatic precipi-
tator. The ESP is designed to maintain a system collection
2 2
efficiency of 99 percent by providing 2850 m (30,700 ft )
of plate area. The 110-hp fan system handles 47 m /s
(100,000 acfm) at a system pressure drop of 1 kPa (4 in.
W.G.). This control strategy will meet a typical state
particulate emission control standard of 0.1 g/kg charge
(0.1 lb/1000 Ib).
The capital costs are estimated at $926,000, including
ESP, spray chamber, pump, holding tank, fan system, and
ductwork.
3-106
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The annualized costs are estimated at $248,000, in-
cluding utilities, labor, maintenance, overhead, and fixed
costs (with capital recovery) .a Sludge disposal costs are
minimal since on-site disposal facilities and equipment are
generally available. A 6000-hour annual operating time and
1500 hours annual labor are assumed.
The capital and annualized costs are expressed below in
terms of exhaust flow rate and annual hours of labor.
S.I, units
Capital, $ = 7.24 x 104V0-6
Annualized, $ = 587V + 19.6H + 1.4 x 104V°'6
V = m3/s at 980°C
H = annual labor hours
23 < V < 210
range
English units
Capital, $ = 732Q0'6
Annualized, $ = 0.277Q + 19.6H + 141Q0'6
Q = acfm at 1800°F
H = annual labor hours
50,000 < Q < 450,000
range
aSee Section 2.9 and Appendix B for discussion of cost analysis.
Detailed cost studies are available from EPA upon request.
3-107
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Cost data for operating municipal incinerators were
compiled by a major manufacturer of pollution control
equipment. Figure 3-18 shows total capital costs as a
function of gas volume for various control devices.
Annualized costs are given in Figure 3-19. The capital
costs are flange-to-flange costs, not including ductwork,
fans, and gas conditioning equipment. The annualized
costs include operating, maintenance, and capital charges.
3.2.3.5 Impacts
A. Emission Reductions
The particulate emission reduction achieved by air
pollution control systems for municipal incinerators are
about 8.5 kg/Mg charge (17 Ib/ton). The lead content is
estimated at 2.4 percent by weight.
B. Energy Impact
The auxiliary heat input ranges from about 5 to 25 per-
cent of the heat content of the charge, depending upon
moisture content and other waste characteristics. The
heating value for typical wastes is about 11 GJ/Mg charge
(11 MM BtiVton), and therefore, 0.6 to 2.8 GJ/Mg charge
(0.6 to 2.8 MM Btu/ton) of auxiliary fuel (oil, natural
gas or pulverized coal) for some incinerators. The ESP
control system for the model incinerator consumes 0.06
GJ/Mg charge (0.06 MM Btu/ton), a 2 to 10 percent increase
3-108
-------
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i
GAS VOLUME, M
40 _ 50 60708090100 150
200 250
80 100
99S ESP
SCRUBBER. AP « 3.7 kPa-
(15" KG)
FABRIC FILTER
SCRUBBER, AP - 1.2 kPa
(5" WG)
95* ESP
CYCLONE, AP
CYCLONE,
AP = 870 Pa
(3 1/2" WG)
1.2 kPa
(5» WG)
SETTLING CHAMBER
200
300
400 500
1000
SAS VOLUME. 10° ACFM
Figure 3-19. Annualized costs for various control
devices on municipal incinerators
(Courtesy of Mr. Robert Morand, Wheelabrator-Frye, Inc,
Cincinnati, Ohio).
3-110
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in energy demand. If a 5 kPa (20 in. WG1* scrubber is
utilized, energy requirements are about 5 times that for
the ESP.
C. Water Pollution Impact
Water is used to quench the incinerator bottom ash
prior to disposal. Two municipal incinerator operations
uses 2.5 to 3.0 m3/Mg charged (600 to 700 gal/ton) for this
26
purpose, most of which is recycled. About 30 £/Mg charge
(8 gal/ton) is needed to sluice the dust collected by the
ESP. The same amount of water is discharged from a scrubber
system which recycles 90 percent of the scrubber water.
D. Solid Waste Impact
The solid waste generated by incineration is the amount
of ash input less the atmospheric emissions. Typical
municipal wastes contain 30 to 50 percent by weight as
27
charged and emit about 8.5 kg/Mg (17 Ib/ton) of waste
incinerated. The solid waste generated is approximately
290 to 490 kg/Mg charge (580 to 980 Ib/ton). The solid
waste generated by air pollution control is about 8.5
kg/Mg charge (17 Ib/ton), an increase of 1.7 to 5.9
percent.
3-111
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3.2.4 Waste Oil Disposal
The various sources of waste oil may be classified into
five broad types: automotive lubricants, metal-working lubri-
cants, heavy hydrocarbon fuels, animal and vegetable oils and
fats, and industrial oil materials. The waste automotive
lubricants include crankcase oils, transmission fluids, dif-
ferential gear lubricants, and hydraulic oils; they originate
mainly from automobile service stations. As a means of
disposal and for recovery of economic and energy values, some
of the waste oil is burned as fuel in industrial and utility
boilers. It is either blended with virgin fuel for use in
power plants, directly fired as in rotary cement kilns, or used
as supplementary fuel in smaller boilers generating steam for
space heating and processing.
O Q
An estimated 1.04 Mm (2.74 x 10 gal) of waste crankcase
oil was consumed as an alternative fuel in 1975. Of the total
O Q
1.82 Mm (4.8 x 10 gal) of waste crankcase oil used in the
U. S., 15 percent was re-refined, 15 percent was used for road
? 8
oil or asphalt, and 13 percent for miscellaneous purposes.
Lead in waste automotive lubricants originates from leaded
gasoline additives. It is estimated that about 5.0 Gg of
lead (5,480 tons) was emitted in 1975 by combustion of waste
oil.
3.2.4.1 Process Description - Waste oil is burned in con-
ventional boiler equipment, as shown earlier in Figure 3-16
3-112
-------
Combustion of untreated waste oil can increase maintenance
requirements, foul and corrode the surfaces of boiler heat
exchangers, and contaminate the environment. Waste oil
t
combustion generates less particulate and SC^ than coal.
The potentially adverse environmental impacts of waste
oil combustion result from significant concentrations of
waste oil contaminants, particularly lead, which may be
emitted in part to the atmosphere with flue gas.
3.2.4.2 Emissions - Lead emissions from sources burning
waste oil depend largely on the lead content of the waste
oil and operating conditions of the combustion source. The
lead content may range from 800 to 11,200 ppm. Average con-
28 30
centrations are given as 6000 ppm and as 10,000 ppm.
Three EPA emission tests established a lead emission
factor of 4.8 (M) kg/m3 of waste oil (40 M lb/103 gal), where
O I
M is the lead content of waste oil in percent. These tests
and other information on combustion sources using waste oil
directly or in a blend with fuel oil indicate that about 50
percer r of the lead is emitted with the flue gas during the
?Q 11 ^8
normal operation. ' A total of 1.04 MmJ (2.74 x 10° gal)
f\ i
of waste oil was fired in combustion processes in 1975.
Therefore, at a 50 percent emission rate, the estimated annual
uncontrolled lead emission from combustion sources using
waste oil (assuming 10,000 ppm by weight lead) was 5.0 Gg
(5,480 tons).
3-113
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The lead in the flue gas from waste oil combustion is
emitted as particulate. In tests conducted recently by
Exxon Research and Engineering using 10 percent: waste oil
in combustion the particulate emitter contained 14 to 19
70 _
(average 16) weight percent lead." in addition to being
present in the flue gas; the lead is a principal constituent
of the ash produced in combustion, accounting for 35 percent
of the total ash content. The ash content from combustion
of waste oil lubricants ranges from 0.03 c '-,.78 weight
percent, which is higher than that produced from cjuibutstion
f} C
of distillate or residual fuel oi... " Tabl^ 3-20 gives
characteristics of exhaust gas from a waste oil-fired boiler.
Additional information on typical contents of lead and
the fraction of input lead emitted would enable a more
accurate assessment of emission factors. Data concerning the
effects of equipment capacities, burner configuration, and
operating conditions on lead emissions would also be useful.
3.2,4,3 Control Techniques - Currently, particulate control
is not usually applied at oil-fired combustion sources.
Blends of waste oil with virgin fuel in low ratios (1 to 5%
by volume) can also be burned1 in combustion sources with no
control without exceeding par ticul..ate emissi:;r. regulations.
Emissions of lead i.roir burnirg op w-jisue oil can be
minimizec b^ rccetrea timer, n": ~-Il orior to combustion or by
use .if hi 2;h~r-"f ioi PP. '-- :.:>-_ L ate control. The protreat-
ment methods indua^:- \,-n: u .<;. .ii.<= zi'1- 1 it ion or solvent extraction
3-114
-------
32
settling, and/or centrifuging. These pretreatment techniques
may alleviate technical problems associated with the storage,
transport, and burning of waste oil, but they will not sig-
nificantly reduce the submicron-sized constituents of the waste
29
oil and may cause the use of waste oil to be uneconomical.
The increased use of low-lead fuels in automobiles will
proportionately decrease the lead content of crankcase oils.
Even though not in widespread use, high-efficiency
particulate control devices can control lead and other sub-
micron- sized emissions from oil combustion. Fabric filters,
electrostatic precipitators, and to a lesser degree, high-
energy venturi scrubbers are all capable of removing sub-
micron-sized particles. Studies have shown that baghouses can
29
successfully remove about 99 percent of submicron particulate.
A properly operated and maintained baghouse is capable of
achieving efficiencies greater than 99.99 percent for 0.5-
micron-diameter particulate.
The most economical and environmentally favorable
2 q
options for utilizing waste oil are stated as follows:
(1) Large users, especially utilities, could blend
small percentages of a partially treated or
untreated waste oil with their current fuel
without necessarily adding emission control
equipment.
(2) Medium-sized users now operating effective emission
control equipment could blend high or low-treated
waste oil with their other fuels.
3-115
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Table 3-20. CHARACTERISTICS OF UNCONTROLLED EXHAUST
GAS FROM MEDIUM AND LARGE WASTE OIL-FIRED BOILERS
Parameter
Gas flow rate
Temperature
Moisture
content
Grain loading
Particle size
distribution
Emission
factors
° particulate
Standard
international
units
1.7 m3/s-MW
150°C
9-11% v
0.2-0.5 g/ m3
I virgin oil)
(100* waste oil)
76-79% w i-b. < 1 prn
16-21* - i-b. < 1-10 i>:n
2, "-4. 1 i w Pb < 10 pra
2.3 kg/m3
(virgin oil)
0 lead I 4 . 8 K ka/ra^
i
English
units
350 scfm/MM
Btu/hr input
300°F
9-11% v
0.1-0.2 gr/scfd
(virgin oil)
(100% waste oil)
76-79 % w Pb < 1 pm
16-21% w Pb < 1-10 pm
2.7-4.4% w Pb < 10 ym
19 lb/103 gal
(virgin oil)
40 M lb/103 gal
References
7
7
7
7
29
8
Particulate emissions vary according to type of boiler and
grade of fuel burned. See Section 4.2 for specific emission
factors.
M is the percent by weight of lead in the oil-normally about
one percent.
3-116
-------
(3) Relatively small users could burn highly-treated
waste oil (after lead removal) by itself.
3.2.4.4 Control Costs - The economics of waste oil com-
bustion are based on the fuel costs and operating charges
associated with burning a specific fuel. If particulate
control equipment were required, the costs would not be
greatly different from those associated with coal-fired
boilers, possibly 10 to 20 percent less. Depending on fuel
costs, the addition of control equipment would shift the
economics away from the use of waste oils as fuel and
probably would cause the owner to burn only virgin fuel.
O (.
One report states that more than 11.4 km (3 x 10 gal)
of waste oil must be burned in a boiler in order to offset
29
annualized control costs.
3-117
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3.2.5 References for Section 3.2
1. National Emission Data System (NEDS). U. S.
Environmental Protection Agency. Research Triangle
Park, N. C. Updated May 1975.
2. Davidson, R. L., et al. Trace Elements in Fly Ash.
Env. Sci. & Tech. 13. 1974. p. 1107-1113.
3. McSich, F. G., et al. Coal Fired Power Plant Trace
Element Study. Radian Corp., Austin, Texas. Environ-
mental Protection Agency. Region VIII. Contract No.
68-01-2663. September 1975. p. 22.
4. Bolton, N. E., et al. Trace Element Measurements at
the Coal-Fired Allen Steam Plant. February 1973-July
1973. Oak Ridge, Tennessee, National Laboratory. For
U. S. Atomic Energy Commission. Contract No. W-7405-
Eng.-26. June 1974. pp. 3-5.
5. Survey of Lead in the Atmosphere of Three Urban
Communities. U. S. D. HEW, PHS, National Air Pollution
Control Administration,, NAPCA Pub. No. AP-12,
Raleigh, N. C. April 1970. p. 94,
6, Abernathy, R. F., M. J. Peterson, and F. H, Gibson,
Spectrochemical Analysis of Coal Ash for Trace Elements,
Burea of Mines. RI 7281. July 1969,
7. Danielson, J. A. (ed.). Air Pollution Engineering
Manual. 2nd Edition. Air Pollution Control District,
County of Los Angeles. Environmental Protection Agency.
Research Triangle Park, N. C. AP-40. Chapter 9.
May 1973.
8. Compilation of Air Pollutant Emission Factors. 2nd
Edition. U. S. Envii-onmental Protection Agency.
Research Triangle Park, N. C. Publication AP-42.
February 1976.
9. Billings, C. E. (ed). Fabric Filter Manual, The
Mcllvaine Company. Northbrook, Illinois. February 1976,
10. Nichols, G. B. (ed). Electrostatic Precipitator
Manual. The Mcllvaine Company. Northbrook, Illinois.
February 1976.
11. The Mcllvaine Scrubber Manual Volume III. Mcllvaine
Company. Northbrook, Illinois. 1974.
31 i <
j. i (
-------
12. Gibbs, L. and T. Ponder. Model Plant Cost Estimates
for ESP's on Coal-Fired Utility-Sized Boilers. PEDCo-
Environmental Specialists, Inc., Cincinnati, Ohio. For
U.S. Environmental Protection Agency. August 1976.
13. Personal communication with Mr. David Noe. PEDCo-
Environmental, Cincinnati, Ohio. October 11, 1977.
14. Breese, F. National Petroleum News Factbock. McGraw-
Hill. New York. Mid-May 1976.
15. Davis, W.E. Emission Study of Industrial Sources of
Lead Air Pollutants, 1970. W.E. Davis and Associates.
Leawood, Kansas. Contract No. 68-02-0271. April 1973.
16. Smith, W.S. Atmospheric Emissions from Fuel Oil Com-
bustion. U.S. Dept. HEW. Taft Sanitary Engrg. Center.
Cincinnati, Ohio. November 1962.
17. Levy, A., S.E. Miller, R.E. Barrett, E.J. Schulz, R.H,
Melvin, W.H. Axtman, and D.W. Locklin. A Field Inves-
tigation of Emission from Fuel Oil Combustion for Space
Heating. Battelle, Columbus. Presented at American
Petroleum Institute Committee on Air and P?ater Conser-
vation Meeting at Columbus, Ohio. November I, 1971.
18. Test No. 71-CI-08. Emission Testing Branch. Environ-
mental Protection Agency. Research Triangle Park, N.C.
April 19-23, 1971.
19. Hora, C.A., A.T. Myers, P.J. Dunton, and H.J. Heyden.
Metals in Crude Oils. Geological Survey Bulletin 1100.
U.S. Government Printing Office. Washington, D.C.
1961.
20. Resource Recovery and Waste Reduction. Third Report to
Congress. U.S. Environmental Protection Agency.
Office of Solid Waste Management Programs. 1975.
21. Hopper, T.G. and W.A. Marrone. Impact of New Source
Performance Standards on 1985 National Emissions from
Stationary Sources. Volume I. The Research Corpora-
tion of New England. For Environmental Protection
Agency. Research Triangle Park, N.C. Contract No.
68-02-1382. Task 3. October 24, 1975.
3-119
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22. Yost, K.J. The Environmental Flow of Cadmium and Other
Trace Metals. Purdue University. West Lafayette,
Indiana. NSF (RANN) Grant Gl - 35106. Progress
Report. July 1, 1973 to June 30, 1974. 287 p.
23. Closs, F.L., R.J. Drago, and H.E. Francis. Metal and
Particulate Emissions from Incinerators Burning Sewage
Sludge. Proceedings of the 1970 National Incinerator
Conference of ASME. 1970. 6 p.
24. Weinstein, N.J. and R.F. Toro. Control Systems on
Municipal Incinerators. Environmental Science and
Technology. June 1976. pp. 545-547.
25. Personal communication with Mr. John Bruck. PEDCo
Environmental, Cincinnati, Ohio. October 11, 1977.
26. Wilson, D.A. and R.E. Brown. Characteristics of Several
Incinerator Process Wastewaters. Proceedings of the
1968 National Incinerator Conference. ASME. New York,
NY. 1968, p. 196,
27. Kaiser, E.R., et al. Municipal Incineration of Refuse
and Residue. Proceedings of the 1968 National
Incinerator Conference. ASME. New York, NY. 1968.
28. Wyatt, S., et al. Preferred Standards Path Analysis
on Lead Emissions from Stationary Sources, Volume I-IV.
U.S. Environmental Protection Agency. Research Triangle
Park, N.C. September 14, 1974.
29. Chansky, S., et al. Waste Automotive Lubricating Oil
Reuse as a Fuel. U.S. Environmental Protection Agency.
ORD. Washington, D.C. EPA Contract No. 68-01-1859.
September 1974.
30. Final Report of the API Task Force on Used Oil
Disposal. API Committee for Air and Water Conservation.
American Petroleum Institute. New York, NY. May 1970.
31. Test No. 71-CI-09. Emission Testing Branch, U.S.
Environmental Protection Agency. Research Triangle
Park, N.C. April 19-23, 1971.
32. Quang, Dang Vu, et al. Spent Oil Reclaimed Without Acid
Hydrocarbon Processing. _5_5_(12): 130-131.
33. GCA/Technology Division. Fabric Filter Systems Study.
Report to National Air Pollution Control Administration.
December 1970.
3--120
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