United State*
Environmental Protection
Agency
Office of Air Quality
Planning And Standard*
Research Triangle Park, NC 27711
EPA-454/R-93-023
September 1993
AIR
LOCATING AND ESTIMATING
AIR EMISSIONS FROM
SOURCES OF MERCURY AND
MERCURY COMPOUNDS
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EPA-453/R-93-023
September 1993
LOCATING AND ESTIMATING AIR EMISSIONS
FROM SOURCES OF MERCURY AND
MERCURY COMPOUNDS
By
Ms. Robin Jones
Dr. Tom Lapp
Dr. Dennis Wallce
Midwest Research Institute
Gary, North Carolina
Contract Number 68-D2-0159
EPA Project Officer: Anne A. Pope
U. S. ENVIRONMENTAL PROTECTION AGENCY
Office Of Air and Radiation
Office Of Air Quality Planning And Standards
Research Triangle Park, North Carolina 27711
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This report has been reviewed by the Office of Air Quality Planning
and Standards, U. S. Environmental Protection Agency, and has been
approved for publication. Mention of trade names or commercial
products does not constitute endorsement or recommendation for use.
EPA 454/R-93-023
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TABLE OF CONTENTS
Section Page
EXECUTIVE SUMMARY xiii
1 PURPOSE OF DOCUMENT 1-1
2 OVERVIEW OF DOCUMENT CONTENTS 2-1
3 BACKGROUND 3-1
3.1 NATURE OF THE POLLUTANT 3-1
3.2 OVERVIEW OF PRODUCTION, USE, AND EMISSIONS . 3-3
3.2.1 Production 3-3
3.2.2 End-Use 3-6
3.2.3 Emissions 3-9
4 EMISSIONS FROM MERCURY PRODUCTION 4-1
4.1 PRIMARY MERCURY PRODUCTION 4-1
4.1.1 Process Description 4-2
4.1.2 Emission Control Measures ...... 4-6
4.1.3 Emissions ' 4-7
4.2 SECONDARY MERCURY PRODUCTION 4-8
4.2.1 Process Description 4-9
4.2.2 Emission Control Measures 4-11
4.2.3 Emissions 4-11
4.3 MERCURY COMPOUNDS PRODUCTION 4-12
4.3.1 Process Description 4-13
4.3.2 Emission Control Measures 4-19
4.3.3 Emissions . . . . 4-20
5 EMISSIONS FROM MAJOR USES OF MERCURY 5-1
5.1 CHLOR-ALKALI PRODUCTION USING THE
MERCURY CELL PROCESS , 5-1
5.1.1 Process Description 5-3
5.1.2 Emission Control Measures 5-5
5.1.3 Emissions 5-7
5.2 BATTERY MANUFACTURING . 5-11
5.2.1 Mercuric Oxide Batteries 5-12
5.2.2 Alkaline-Manganese Batteries .... 5-18
5.2.3 Leclanche' Zinc-Carbon Batteries . . 5-22
5.3 ELECTRICAL USES 5-24
5.3.1 Electric Switches 5-24
5.3.2 Thermal Sensing Elements 5-30
5.3.3 Tungsten Bar Sintering 5-33
5.3.4 Copper Foil Production 5-34
5.3.5 Fluorescent Lamp Manufacture .... 5-35
5.4 INSTRUMENT MANUFACTURING AND USE
(THERMOMETERS) 5-37
5.4.1 Process Description 5-38
5.4.2 Emission Control Measures 5-39
5.4.3 Emissions 5-39
iii
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TABLE OF CONTENTS (continued)
Section Page
6 EMISSIONS FROM COMBUSTION SOURCES 6-1
6.1 COAL COMBUSTION 6-5
6.1.1 Coal Characteristics ........ 6-6
6.1.2 Process Description 6-12
6.1.3 Emission Control Measures ...... 6-15
6.1.4 Emissions 6-16
6.2 FUEL OIL COMBUSTION 6^21
6.2.1 Fuel Oil Characteristics 6-23
6.2.2 Process Description 6-24
6.2.3 Emission Control Measures 6-28
6.2.4 Emissions 6-29
6.3 NATURAL GAS COMBUSTION 6-34
6.3.1 Natural Gas Characteristics 6-35
6.3.2 Process Description 6-35
6.3.3 Emission Control Measures 6-36
6.3.4 Emissions 6-36
6.4 WOOD COMBUSTION .- 6-36
6.4.1 Process Description "... 6-37
6.4.2 Emission Control Measures 6-39
6.4.3 Emissions 6-40
6.5 MUNICIPAL WASTE COMBUSTION 6-41
6.5.1 Municipal Solid Waste Characteristics 6-42
6.5.2 Process Description . . . 6-42
6.5.3 Emission Control Measures 6-49
6.5.4 Emissions 6-51
6.6 SEWAGE SLUDGE INCINERATORS .6-52
6.6.1 Process Description 6-54
6.6.2 Emission Control Measures 6-59
6.6.3 Emissions 6-60
6.7 MEDICAL WASTE INCINERATION 6-62
6.7.1 Process Description 6-64
6.7.2 Emission Control Measures 6-69
6.7.3 Emissions 6-69
7 EMISSIONS FROM MISCELLANEOUS SOURCES 7-1
7.1 PORTLAND CEMENT MANUFACTURING 7-1
7.1.1 Process Description 7-2
7.1.2 Emission Control Measures 7-6
7.1.3 Emissions 7-7
7.2 LIME MANUFACTURING 7-8
7.2.1 Process Description 7-10
7.2.2 Emission Control Measures 7-12
7.2.3 Emissions 7-12
7.3 CARBON BLACK PRODUCTION 7-14
7.3.1 Process Description 7-14
7.3.2 Emission Control Measures .' . " 7-r&
7.3.3 Emissions 7-18
iv
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TABLE OF CONTENTS (continued)
Section Page
7.4 BYPRODUCT COKE PRODUCTION 7-18
7.4.1 Process Description 7-20
7.4.2 Emission Control Measures 7-23
7.4.3 Emissions 7-24
7.5 PRIMARY LEAD SMELTING 7-24
7.5.1 Process Description 7-25
7.5.2 Emission Control Measures 7-27
7.5.3 Emissions 7-27
7.6 PRIMARY COPPER SMELTING 7-29
7.6.1 Process Description 7-30
7.6.2 Emission Control Measures 7-36
7.6.3 Emissions 7-36
7.7 'PETROLEUM REFINING 7-37
7.7.1 Process Description 7-38
7.7.2 Emission Control Measures 7-43
7.7.3 Emissions 7-43
7.8 OIL SHALE RETORTING 7-45
7.8.1 Process Description 7-45
7.8.2 Emission Control Measures 7-46
7.8.3 Emissions 7-46
7.9 GEOTHERMAL POWER PLANTS 7-46
7.9.1 Emission Control Measures 7-47
7.9.2 Emissions 7-47
8 EMISSIONS FROM MISCELLANEOUS FUGITIVE AND AREA
SOURCES 8-1
8.1 MERCURY CATALYSTS 8-1
8.1.1 Process Description 8-1
8.1.2 Emission Control Measures 8-3
8.1.3 Emissions 8-3
8.2 DENTAL ALLOYS 8-4
8.2.1 Process Description 8-4
8.2.2 Emission Control Measures 8-4
8.2.3 Emissions 8-5
8.3 MOBILE SOURCES 8-5
8.3.1 Emissions 8-5
8.4 CREMATORIES 8-6
8.5 PAINT USE 8-8
8.6 SOIL DUST 8-9
8.7 NATURAL SOURCES OF MERCURY EMISSIONS .... 8-10
9 SOURCE TEST PROCEDURES 9-1
9.1 INTRODUCTION 9-1
9.2 DEDICATED MERCURY SAMPLING METHODS 9-3
9.2.1 EPA Method 101-Determination of
Particulate and Gaseous Mercury
. . -. Emissions from Chlor-Alkali Plants . • 9-3
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TABLE OF CONTENTS (continued)
Section
9.2.2 EPA Method 101A-Determination of
Particulate and Gaseous Mercury
Emissions from Sewage Sludge
Incinerators
9.2.3 EPA Method 102-Determination of
Particulate and Gaseous Mercury
Emissions from Chlor-Alkali
« Plants-Hydrogen Streams . . . . .
9.3 MULTIPLE METALS SAMPLING TRAINS
9.3.1 Method 0012-Methodology for the
Determination of Metals Emissions
in Exhaust Gases from Hazardous
Waste Incineration and Similar
Combustion Sources
9.3.2 CARS Method 436-Determination of
Multiple Metals Emissions from
Stationary Sources .......
9.4 ANALYTICAL METHODS FOR DETERMINATION
OF- MERCURY 1 . . .
9.5 SUMMARY
10 REFERENCES •
APPENDIX A. NATIONWIDE EMISSION ESTIMATES ....
APPENDIX B. SUMMARY OF COMBUSTION SOURCE MERCURY
EMISSION DATA
APPENDIX C. SELECTED INFORMATION FOR CEMENT KILNS
AND LIME PLANTS
APPENDIX D. CRUDE OIL DISTILLATION CAPACITY . . .
Page
9-5
9-6
9-6
9-6
9-9
9-9
9-10
10-1
A-l
B-l
C-l
D-l
vi
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LIST OF FIGURES
Ficrure Page
3-1 1991 supply and demand of mercury 3-5
3-2 End-use pattern of mercury 3-7
4-1 Major components of mercury recovery from gold
ores 4-4
4-2 Process flow diagram for secondary recovery at
a battery plant ..... 4-10
4-3 Mercuric/mercurous chloride production 4-15
4-4 Mercuric oxide production via mercuric chloride
and mercuric nitrate intermediates 4-16
4-5 Process flow diagram for production of
phenylmercuric acetate 4-18
5-1 Basic flow diagram for a mercury-cell
chlor-alkali operation 5-4
5-2 General flow diagram for mercuric oxide battery
manufacture 5-14
5-3 Alkaline cell manufacture . 5-21
5-4 Manufacture of mercury buttons for wall
switches 5-26
5-5 Thermostat switch manufacture . . , = 5-27
6-1 Distribution of sewage sludge incinerators in
the U.S 6-55
6-2 Process flow diagram for sludge incineration . . 6-56
6-3 Major components of an incineration system ... 6-65
7-1 Process flow diagram of Portland cement
manufacturing process 7-3
7-2 Process flow diagram for lime manufacturing
process . f 7-11
vii
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LIST OF FIGURES (continued)
Figure Page
7-3 Process flow diagram for carbon black
manufacturing process 7-17
7-4 Schematic of byproduct coke oven battery .... 7-21
7-5 Types of air pollution emissions from coke
oven batteries 7-22
7-6 Typical primary lead processing scheme 7-26
7-7 Typical primary copper smelter process 7-31
7-8 Schematic of an example integrated .
petroleum refinery 7-39
7-9 Schematic of fluidized bed catalytic
cracking unit 7-41
8-1 Vinyl chloride process using a mercuric
chloride catalyst 8-2
9-1 Typical dedicated mercury sampling train .... 9-4
9-2 Typical multiple metals sampling train ..... 9-8
viii
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LIST OF TABLES
Table Page
ES-1 ESTIMATED NATIONWIDE EMISSIONS xiv
3-1 PHYSICAL AND CHEMICAL PROPERTIES OF MERCURY ... 3-2
3-2 COMPARISON OF MERCURY DEMAND BY USER INDUSTRY
IN 1989 AND 1991 3-8
3-3 POTENTIAL SOURCE CATEGORIES OF MERCURY
EMISSIONS 3-11
3-4 ESTIMATED 1990 NATIONWIDE MERCURY EMISSIONS FOR
SELECTED SOURCE CATEGORIES 3-14
4-1 BYPRODUCT MERCURY-PRODUCING GOLD MINES IN THE
UNITED STATES IN 1991 4-3
4-2 MERCURY EMISSION FACTORS FOR PRIMARY MERCURY
PRODUCTION 4-7
4-3, U.S. MERCURY RECYCLERS IN 1989 4-8
4-4 MERCURY COMPOUND PRODUCERS 4-13
5-1 MERCURY CELL CHLOR-ALKALI PRODUCTION
FACILITIES 5-2
5-2 - MERCURY EMISSION RATES FOR CHLOR-ALKALI
PRODUCTION FACILITIES 5-9
5-3 MERCURY-CONTAINING BATTERIES 5-11
5-4 MERCURIC OXIDE ALKALINE MANGANESE OR ZINC-CARBON
BATTERY MANUFACTURERS IN 1992 5-13
5-5 METHODS FOR REDUCING WORKER EXPOSURE TO MERCURY
EMISSIONS IN BATTERY MANUFACTURING 5-17
5-6 EMISSION SOURCE PARAMETERS FOR AN INTEGRATED
MERCURY BUTTON CELL MANUFACTURING FACILITY . . 5-19
5-7 MEASURES TO REDUCE WORKPLACE EXPOSURE TO MERCURY
VAPOR EMISSIONS IN THE ELECTRIC SWITCH
INDUSTRY 5-29
5-8 MANUFACTURERS OF ELECTRIC SWITCHES AND ELECTRONIC
COMPONENTS REPORTING IN THE 1990 TOXICS
RELEASE INVENTORY 5-31
ix
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LIST OF TABLES (continued)
Table Page
5-9 FLUORESCENT LAMP MANUFACTURING 5-35
6-1 DISTRIBUTION OF FOSSIL FUEL CONSUMPTION IN THE
UNITED STATES 6-3
6-2 COAL HEATING VALUES 6-7
6-3 EXAMPLES OF COAL HEAT CONTENT VARIABILITY .... 6-8
6-4 MERCURY CONCENTRATION IN COAL BY COAL TYPE ... 6-10
6-5 MERCURY CONCENTRATION IN COAL BY REGION ..... 6-11
6-6 CALCULATED UNCONTROLLED MERCURY EMISSION FACTORS
FOR COAL COMBUSTION 6-18
6-7 SUMMARY OF MERCURY EMISSION. FACTORS FOR COAL
COMBUSTION .6-20
6-8 BEST TYPICAL MERCURY EMISSION FACTORS FOR COAL
COMBUSTION 6-22
6-9 TYPICAL HEATING VALUES OF FUEL OILS 6-25
6-10 TYPICAL FUEL OIL HEATING VALUES FOR SPECIFIC
REGIONS 6-26
6-11 MERCURY CONCENTRATION IN OIL BY OIL TYPE .... 6-27
6-12 CALCULATED UNCONTROLLED MERCURY EMISSION FACTORS
FOR FUEL OIL COMBUSTION 6-30
6-13 MEASURED MERCURY EMISSION FACTORS FOR FUEL OIL
COMBUSTION , -6-31
6-14 MERCURY EMISSION FACTORS FOR FUEL OIL COMBUSTION
GENERATED FROM CALIFORNIA "HOT SPOTS" TESTS . . 6-33
6-15 BEST TYPICAL MERCURY EMISSION FACTORS FOR FUEL OIL
COMBUSTION 6-34
6-16 SUMMARY OF MERCURY EMISSION FACTORS FOR WOOD
COMBUSTION . . 6-41
6-17 SUMMARY OF GEOGRAPHICAL DISTRIBUTION OF MWC
FACILITIES 6-43
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LIST OF TABLES (continued)
Table Page
6-18 CURRENT AND FORECAST COMPOSITION OF DISPOSED
RESIDENTIAL AND COMMERCIAL WASTE (WEIGHT
PERCENT) 6-44
6-19 BEST TYPICAL MERCURY EMISSION FACTORS FOR
MUNICIPAL WASTE COMBUSTORS 6-53
6-20 SUMMARY OF MERCURY EMISSION FACTORS FOR SEWAGE
SLUDGE INCINERATORS 6-61
6-21 BEST TYPICAL MERCURY EMISSION FACTORS FOR SEWAGE
SLUDGE INCINERATORS 6-62
6-22 SUMMARY OF UNCONTROLLED MERCURY EMISSION FACTORS
FOR MEDICAL WASTE INCINERATORS 6-72
6-23 SUMMARY OF CONTROLLED MERCURY EMISSION FACTORS AND
CONTROL EFFICIENCIES FOR MEDICAL WASTE
INCINERATORS 6-74
6-24 BEST TYPICAL UNCONTROLLED MERCURY EMISSION FACTORS
FOR MEDICAL WASTE INCINERATORS 6-75
7-1 LIME PRODUCERS IN THE UNITED STATES IN 1989 ... 7-9
7-2 CARBON BLACK PRODUCTION FACILITIES . ' 7-15
7-3 BYPRODUCT COKE PRODUCERS IN THE UNITED STATES
IN 1991 7-19
7-4 DOMESTIC PRIMARY LEAD SMELTERS AND REFINERIES . . 7-24
7-5 MERCURY EMISSION FACTORS FOR PRIMARY
LEAD SMELTING 7-28
7-6 DOMESTIC PRIMARY COPPER SMELTERS AND REFINERIES . 7-30
7-7 MERCURY EMISSION FACTORS FOR MISCELLANEOUS
SOURCES AT PETROLEUM REFINING FACILITIES ... 7-44
7-8 CURRENT OPERATING GEOTHERMAL POWER PLANTS IN THE
UNITED STATES IN 1992 7-48
7-9 MERCURY EMISSION FACTORS FOR GEOTHERMAL POWER
PLANTS . 7-48
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LIST OP TABLES (continued)
Table Page
8-1 1991 U.S. CREMATORY LOCATIONS BY STATE ..... 8-7
9-1 MERCURY SAMPLING METHODS 9-2
xii
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EXECUTIVE SUMMARY
The emissions of mercury and mercury compounds into the
atmosphere are of special significance because of the Clean Air
Act Amendments of 1990. These amendments mandate that mercury
emissions be subject to standards that allow for the maximum
degree of reduction of emissions and that,, by 1995, a list of
source categories must be established that account for no less
than 90 percent of mercury emissions. This document is designed
to assist groups interested in inventorying air emissions of
mercury by providing a compilation of-available information on
sources and emissions of these substances.
In the U.S., mercury is produced primarily as a byproduct
of gold mining and as a result of secondary production; the last
mercury mine was closed in 1990. In 1991, the total U.S. supply
of mercury was 1,416 Mg (1,558 tons), of which approximately
4 percent resulted from imports. The demand for mercury in the
U.S. has decreased sharply since 1989. In 1991, the U.S. demand
was only 473 Mg (520 tons) or 3j percent of the supply. This
represents a demand that is only 39 percent of the 1989 demand.
The majority of the 1991 supply was for exports, which accounted
for 56 percent of the supply; the remaining 11 percent was used
to replenish industry stocks.
In 1991, 10 source categories accounted for the U.S. demand
for mercury; the chlor-alkali industry was the major user. Other
major users of mercury were for battery production and production
of measurement and control instruments. .These three source
categories accounted for 70 percent of the total U.S. demand for
xiii
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mercury; the other seven source categories accounted for the
remaining 30 percent.
Nationwide mercury emissions were estimated for several
source categories for 1990. This was the latest year for which
adequate information was available for all source categories and
it was not desirable to mix the specific source emission
estimates for 1990 and 1991. The total 1990 nationwide mercury
emissions estimate was 302 Mg (332 tons) from five major source
categories. Table ES-1 shows the estimated nationwide emissions
by major source category and the percent contribution of each
category to the total emissions. The five specific sources
emitting the largest quantities of mercury were coal combustion,
municipal waste combustion, medical waste combustion, oil
combustion, and paint application.
TABLE ES-1. ESTIMATED NATIONWIDE EMISSIONS
Major source
category
Mercury and mercury
compound production
Major uses of
mercury
Combustion sources
Miscellaneous
manufacturing
processes
Other miscellaneous
sources
TOTAL
Estimated nationwide
emissions, Mg (tons)
5.7 (6.3)
18.4 (20.2)
243 (267.5)
15.9 (17.5)
18.6 (20.6)
302 (332)
Percent of
total emissions
1.9
6.1
80.5
5.3
6.2
100
XIV
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SECTION 1
PURPOSE OF DOCUMENT
The U. S. Environmental Protection Agency (EPA), State, and
local air pollution control agencies are becoming increasingly
aware of the presence of substances in the ambient air that may
be toxic at certain concentrations. This awareness, in turn, has
led to attempts to identify source/receptor relationships for
these substances and to develop control programs to regulate
emissions. Unfortunately, little information exists on the
ambient air concentration of these substances or about the
sources that may be discharging them to the atmosphere.
To assist groups interested in inventorying air emissions of
various potentially toxic substances, EPA is preparing a series
of documents such as this that compiles available information on
sources and emissions of these substances. Prior documents in
the series are listed below:
Substance
Acrylonitrile
Carbon Tetrachloride
Chloroform
Ethylene Bichloride
Fo rma 1 dehyde
Nickel
Chromium
Manganese
Phosgene
Epichlorohydrin
Vinylidene Chloride
Ethylene Oxide
Chlorobenzene
EPA Publication Number
EPA-450/4-84-007a
EPA-450/4-84-007b
EPA-450/4-84-007C
EPA-450/4-84-007d
EPA-450/4-91-012
EPA-450/4-84-007f
EPA-450/4-84-007g
EPA-450/4-84-007h
EPA-450/4-84-007i
EPA - 4 5 0/4 - S4-- 00 7 j
EPA-450/4-84-007k
EPA-450/4-84-0071
EPA-450/4-84-007m
1-1
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Polychlorinated Biphenyls (PCB's) EPA-450/4-84-007n
Polycyclic Organic Matter (POM) EPA-450/4-84-007p
Benzene EPA-450/4-84-007q
Perchloroethylene and EPA-450/2-89-013
Tri chloroethylene
Municipal Waste Combustion EPA-450/2-89-006
Coal and Oil Combustion EPA-450/2-89-001
1,3-Butadiene EPA-450/2-89-021
Chromium (Supplement) EPA-450/2-89-002
Sewage Sludge EPA-450/2-90-009
Styrene EPA-454/R-93-011
Cadmium Number to be Assigned
Methylene Chloride EPA-454/R-93/006
Medical Waste Number to be Assigned
TCDD/TCDF Number to be Assigned
Toluene • Number to be Assigned
Xylenes Number to be Assigned
Methyl Ethyl Ketone Number to be Assigned
Methyl Chloroform Number to be Assigned
Chlorobenzene (Update) Number to be Assigned
Chloroform (Update) Number to be Assigned
This document deals specifically with mercury and mercury
compounds; however, the majority of the information contained in
this document concerns mercury.
In addition to the information presented in this document,
another potential source of emissions data for mercury and
mercury compounds is the Toxic Chemical Release Inventory (TRI)
form required by Section 313 of Title III of the 1986 Superfund
Amendments and Reauthorization Act (SARA 313J.1 SARA 313
requires owners and operators of facilities in certain Standard
Industrial Classification Codes that manufacture, import, process
or otherwise use toxic chemicals (as listed in Section 313) to
report annually their releases of these chemicals to all
environmental media. As part of SARA 313, EPA provides public
access to the annual emissions data. The TRI-data include
general facility information, chemical information, and emissions
.data. .Air emissions data are reported as total facility release
estimates for fugitive emissions and point source emissions. No
1-2
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individual process or stack data are provided to EPA under the
program. The TRI requires sources to use stack monitoring data
for reporting, if available, but the rule does not require stack
monitoring or other measurement of emissions if data from these
activities are unavailable. If monitoring data are unavailable,
emissions are to be quantified based on best estimates of
releases to the environment.
The reader is cautioned that the TRI will not likely provide
facility, emissions, and chemical release data sufficient for
conducting detailed exposure modeling and risk assessment
studies. In many cases, the TRI data are based on annual
estimates of emissions (i.e., on emission factors, material
balance calculations, and engineering judgment). We recommend
the use of TRI data in conjunction with the information provided
in this document to locate potential emitters of mercury and to
make preliminary estimates of air emissions from these
facilities.
Mercury is of particular importance as a result of .the Clean
Air Act Amendments of 1990. Mercury and its compounds are
included in the Title III list of hazardous air pollutants and
will be subject to standards established under Section 112,
including maximum achievable control technology (MACT). Also,
Section 112 (c) (6) of the 1990 Amendments mandate that mercury
(among others) be subject to standards that allow for the maximum
degree of reduction of emissions. These standards are to be
promulgated no later than 10 years following .the date of
enactment. Additionally, within 5 years of the date of
enactment, a list of source categories that account for no less
than 90 percent of mercury emissions must be established.
--"•• The data on mercury emissions are based, whenever possible,
on the results of actual test procedures. Data presented in this
document are total mercury emissions and do not differentiate the
chemical forms of the mercury. The sampling and analysis
1-3
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procedures employed for the determination of the mercury
concentrations from various sources are presented in Section 9,
Source Test Method. These methods do not provide data on the
speciation of the mercury in the emissions.
1-4
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SECTION 2
OVERVIEW OF DOCUMENT CONTENTS
*
As noted in Section l, the purpose of this document is to
assist Federal, State, and local air pollution agencies and
others who are interested in locating potential air emitters of
mercury and mercury compounds and estimating air emissions from
these sources. Because of the limited background data available,
the information summarized in this document does not and should
not be assumed to represent the source configuration or emissions
• . *
associated with any particular facility.
This section provides an overview of the contents of this
document. It briefly outlines the nature, extent, and format of
the material presented in the remaining sections of this
document.
Section 3 of this document provides a brief summary of the
physical and chemical characteristics of mercury and mercury
compounds and an overview of their production and uses. A
chemical use tree summarizes the quantities of mercury produced
by various techniques as well as the relative amounts consumed by
various end uses. This background section may be useful to
someone who wants to develop a general perspective on the nature
of the substance and where it is manufactured and consumed.
Sections 4 'to 7 of this document focus on the major .
industrial source categories that may discharge mercury-
containing air emissions. Section 4 discusses -the production of
mercury and mercury compounds. Section 5 discusses the different
uses of mercury as an industrial feedstock. Section 6 discusses
emissions from combustion sources. Section 7 discusses emissions
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from miscellaneous manufacturing processes, and Section 8
discusses emissions from miscellaneous fugitive and area sources.
For each major industrial source category described, process
descriptions and flow diagrams are given wherever possible,
potential emission points are identified, and available emission
factor estimates are presented that show the potential for
mercury emissions beforehand after controls are employed by
industry. Individual companies are named that are reported to be
involved with the production and/or use of mercury based on
industry contacts, the Toxic Release Inventory (TRI), and
available trade publications.
Section 9 of this document summarizes available procedures
for source sampling and analysis of mercury. Details are not
provided nor is any EPA endorsement given or implied for any of
these sampling and analysis procedures. Section 10 provides
references. Appendix A presents calculations used to derive the
estimated 1990 nationwide mercury emissions. Appendix B presents
a summary of the combustion source test data. Appendix C lists
U.S. Portland cement manufacturers. Appendix D presents U.S.
crude oil distillation capacity.
This document does not contain any discussion of health or
other environmental effects of mercury, nor does it include any
discussion of ambient air levels or ambient air monitoring
techniques.
Comments on the content or usefulness of this document are
welcome, as is any information on process descriptions, operating
practices, control measures, and emissions that would enable EPA
to improve its contents. All comments should be sent to:
Chief, Emission Factor and Methodology Section (MD-14)
Emission Inventory Branch
U. S. Environmental Protection Agency
Research Triangle Park, NC 27711 -..
2-2
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SECTION 3
BACKGROUND
3.1 NATURE OF THE POLLUTANT
Mercury, also called quicksilver, is a heavy, silver-white
metal that exists as a liquid at ambient temperatures. Its
symbol, Hg, comes from the Latin word, hydrargyrum, meaning
liquid silver. Mercury and its major ore, cinnabar (HgS), have
been known and used for thousands of years. Table 3-1 summarizes
the major chemical and physical properties of mercury.
Mercury is stable at ambient temperatures. It does not
react with air, ammonia, carbon dioxide, nitrous oxide, or oxygen
but readily combines with the halogens and sulfur. Mercury will
react with any hydrogen sulfide present in the air and should be
kept in covered containers.2 It is not affected to any extent by
hydrochloric acid but is attacked by concentrated sulfuric acid.
Mercury can be dissolved in either dilute or concentrated nitric
acid, resulting in the formation of either mercurous [Hg(D]
salts (if the mercury is in excess or no heat is applied), or
mercuric [Hg(II)] salts (if excess acid or heat is used).
Elemental (metallic) mercury is used primarily in electrical
applications, including batteries, electrical lamps, and wiring
and switching devices. Its low electrical resistivity makes it
one of the best electrical conductors among the metals.2
In the ionic form, mercury exists in one of two oxidation
states (or valences): Hg(I) or the mercurous ion and Hg(II) or
the mercuric ion. Of the two states, the higher oxidation state,
Hg(II), is the more stable. Mercury compounds having technical ...
and commercial importance include mercuric sulfide, mercuric
3-1
-------
TABLE 3-1. PHYSICAL AND CHEMICAL PROPERTIES OF MERCURY
Property
Value
Atomic weight
Crystal system
CAS registry number
Atomic number
Valences
Outer electron configuration
Metallic radius, A
Covalent radius, A
Electrode reduction
potentials, normal, V
Hg2 + + 2e - Hg
Hg22 + + 2e~2H0
2Hg2 + + 2e - Hg22 +
Melting point, °C
Boiling point, °C
Latent heat of fusion, J/g (cal/g)
Latent heat of vaporization, J/g (cal/g)
Specific heat, J/g (cal/g)
Solid
-75.6°C
-40°C
-263.3°C
Liquid
-36.7°C
210°C
Electrical resistivity, Q-cm, at 20°C
Density, g/cm^
at 20°C
at melting point
at -38.8°C (solid)
atO°C
Thermal conductivity,
w/(cm2 • K)
Vapor pressure, 25°C
Solubility in water, 25 °C
200.59
Rhombohedral
7439-97-6
80
1.2
5d106s2
1.10
1.50
-------
oxide, mercuric chloride, mercuric and mercurous sulfate,
mercurous nitrate, and various organic mercury salts (e.g.,
phenylmercurie acetate).
Metallic mercury can be found in small quantities in some
ore deposits; however, it usually occurs as a sulfide. It occurs
sometimes as the chloride or the oxide, typically in conjunction
with base and precious metals. Although cinnabar (HgS) is by far
the predominant mercury mineral in ore deposits, other common
mercury-containing minerals include corderoite (Hg3S2Cl2),
livingstonite (HgSb4S7), montroydite (HgO), terlinguaite
(Hg20Cl), calomel (HgCl), and metacinnabar, a black form of
cinnabar.2
Mercury has a tendency to form alloys or amalgams with
almost all metals except iron, although at higher temperatures
it will even form alloys w.ith iron. Mercury forms amalgams with
vanadium, iron, niobium, molybdenum, cesium, tantalum, or
tungsten to produce metals with good to excellent corrosion
resistance.2 A mercury-silver amalgam has been traditionally
used for teeth fillings.
3.2 OVERVIEW OF PRODUCTION, USE, AND EMISSIONS
3.2.1 Production
Primary production of mercury occurs principally as a
byproduct of gold mining. Mercury was previously mined from
mercury ores in Nevada, but that mine closed in 1990. It is
still produced in relatively small quantities as a byproduct from
gold ores in Nevada, California, and Utah.4
: Secondary production (recycling) of mercury includes.the
processing of scrapped mercury-containing products, industrial
waste and scrap, and scrap mercury from Government stocks.4
Major sources of recycled mercury are dental amalgams and scrap
3-3
-------
mercury from instrument and electrical manufacturers, wastes and
sludges from research laboratories and electrolytic refining
plants, and mercury batteries.2
Figure 3-1 presents the 1991 supply-and-demand diagram for
mercury. The information contained in Figure 3-1 was obtained
from the U.S. Bureau of Mines, Division of Mineral Commodities.
As shown in Figure 3-1, the total 1991 U.S. supply of mercury was
1,416 Mg (1,558 tons). An estimated 75 percent of the total
supply resulted from the primary and secondary mercury production
processes. The large percentage of the total supply due to
primary and secondary production processes is presumed to be
attributed to the sale of mercury stockpiles from the McDermitt
Mine in Nevada which ceased operation in 1990. Figure 3-1 also
shows that of the total 1991 U.S. mercury supply, 33 percent
(473 Mg/520,tons) was used to meet domestic demands, while
56 percent met export demands and 11 percent supplied industry
stocks.
The 1991 supply-demand figures shown in Figure 3-1 present a
dramatic change in the overall structure of the industrial demand
for mercury in the U.S. A brief review of figures for 1989,
1990, and 1991 reveal the magnitude of the changes that have
occurred.4 In 1989, the U.S. industrial demand for mercury was
1,214 Mg (1,335 tons); in 1990, it was 720 Mg (792 tons); and in
1991, it was 473 Mg (520 tons). Conversely, exports of mercury
in 1989 were 221 Mg-(243 tons); in 1990, exports were 311 Mg
(342 tons); and in 1991, exports reached 786 Mg (865 tons).
Since 1989, U.S. industrial demand has decreased by 61 percent
(741 Mg/815 tons) and'exports have increased by 356 percent
(565 Mg/622 tons). The impacts of these changes can be seen in
the changes in the end uses of mercury.
3-4
-------
IMPORTS: 56(62)-
PRIMARY PRODUCTION AND
CHANGE IN PRODUCER STOCKS8-' 718 (790)-
BVPHOOUCT PRODUCTION: M(M)
CHANGE NPRODUCER STOCKS: WO (720)
UJ
I
01
U.S.
. SUPPLY .
1.416(1.558)
INDUSTRY STOCKS
12/31/91
157 (173)
U.S.
DEMAND •
473(520)
EXPORTS
786 (865)
SECONDARY PRODUCTION: 337 (371)'
INDUSTRY STOCKS (CONSUMER-
AND DEALER): 1/1/91
202(222)
SHIPMENTS OF GOVERNMENT.
STOCKPILE EXCESSES: 103(113)
NOTE: ALL QUANTITIES ARE IN MEGAGRAMS (Mg); QUANTITIES IN PARENTHESES ARE IN TONS.
aThe separate values are withheld to avoid disclosure of compan y priority data.
Includes pigments, Pharmaceuticals, catalysts (or plastics, and misc. catalysts.
clncludes other electrical and electronic uses and other instrument uses.
Figure 3-1. 1991 supply and demand of mercury.4
ELECTRIC LIGHTING
29 (32)
WIRING DEVICES AND
SWITCHES
25(28)
BATTERIES
78(86)
CHLOR-ALKALI
184 (202)
PAINT
6(7)
OTHER CHEMICAL AND
ALLIED PRODUCTS'1
18(20)
MEASURING AND
CONTROL INSTRUMENTS
70(77)
DENTAL EQUIPMENT AND
SUPPLIES
27(30)
LABORATORY
10(11)
OTHER USESC
26(29)
-------
3.2.2 End-Use
Because of its unique qualities and properties, mercury has
various end-uses. Figure 3-1 outlines the 1991 final end-use
pattern for mercury to be:
1. Electric lighting; '
2. Wiring devices and switches;
3. Batteries;
4. Chlor-alkali production;
5. Paint manufacture;
6. Chemical and allied products production;
7. Measuring and control equipment;
8. Dental equipment and supplies;
9. Laboratory uses; and
10. Other miscellaneous uses.
The percentage of the total 1991 mercury supply that was consumed
by each end-use category is shown in Figure 3-2. Chlor-alkali
production, at 38.9 percent, accounts for the largest percentage
consumption of mercury. Battery manufacture and measuring and
control instruments manufacture represent the second and third
largest consumers of mercury at 16.5 percent and 14.8 percent,
respectively. The remaining source categories, as outlined in
Figure 3-1, account for approximately 30 percent of total mercury
consumption in 1991.
During 1989-1991, the demand picture for mercury underwent a
significant change in the overall demand among industries.4 The
magnitude of these overall changes and the dramatic change in
mercury demand for specific industries is shown in Table 3-2 for
the mercury-using industries. These are the same segments shown
in .Figures 3-1 and 3-2.
3-6
-------
Laboratory (2.1%)
Measuring & Control Instruments (14.8%)
Wiring Devices & Switches (5.3%)
Paint (1.3%)
Other Chemical & Allied Products (3.8%)
Other Uses (5.5%)
Dental Equipment & Supplies (5.7%)
Batteries (16.5%)
Electric Lighting (6.1%)
Chlor-alkali (38.9%)
Figure 3-2. End-use pattern of mercury.4
-------
TABLE 3-2. COMPARISON OF MERCURY DEMAND BY
USER INDUSTRY IN 1989 AND 1991
Industry
Electric lighting
Wiring devices/ switches
Batteries
Chlor-alkali
Paint
Other chemical and allied
products
Measuring and control
instruments
Dental equipment/supplies
Laboratory
Other uses
Total demand
Mercury demand, Mg (tons)
1989
31 (34)
141 (155)
250 (275)
381 (419)
192(211)
40 (44)
87 (96)
39 (43)
18 (20)
35 (39)
1,214 (1,335)
1991
29 (32)
25 (28)
78 (86)
1 84 (202)
6(7)
1 8 (20)
70 (77)
27 (30)
10 (11)
26 (29)
473 (520)
Note: Columns may not add due to rounding
Source: Reference 4.
The most dramatic change occurred in the paint industry where
demand dropped to only 6 Mg (7 tons) compared to 192 Mg
(211 tons) in 1989. Other industries showing significant
decreases in demand were wiring devices and switches, batteries,
chlor-alkali, and, to a lesser extent, other chemicals and allied
products.
The demand decreases in end-use areas will definitely affect
the magnitude of mercury emissions in the U.S. and will lead to
secondary impacts. One secondary major impact on emissions will
be in the area of waste disposal, particularly in municipal and
medical waste combustion. In medical waste, used batteries and
used laboratory equipment constitute a major source of mercury
and mercury emissions during incineration. The mercury demand
3-8
-------
for laboratory uses decreased by 50 percent but was at a
relatively low level at the start (18 Mg/20 tons). Mercury use
in batteries showed a major decrease in quantity
(172 Mg/189 tons), and this decrease should be evident in mercury
emissions from both medical waste and municipal waste
incineration. In addition, the significant decrease in demand
for the wiring devices and switches industry may also be felt in
emissions from municipal waste incinerations. This impact would
occur further in the future than the impact from batteries
because of the longer equipment lifetime.
3.2.3 Emissions
The source of emissions information used to determine a
portion of the source categories is the 1990 Toxic Chemicals
Release Inventory System (TRI) form required by Section 313 of
Title III of the 1986 Superfund Amendments and Reauthorization
Act (SARA 313).^ This section requires owners and operators of
facilities in Standard Industrial Classification (SIC)
codes 20-39 that manufacture, import, process, or otherwise use
toxic chemicals to report their annual air releases of these
chemicals. The emissions are to be based on source tests (if
available); otherwise, emissions may be based on emission
factors, mass balances, or other approaches. Certain source
categories (i.e., combustion sources) that account for
substantial mercury emissions, but which are not represented in
TRI, were included in the estimates presented.
It should be noted that, in selected cases, facilities
reported to TRI under multiple SIC codes. As a result, it was
difficult to assign emissions to a specific SIC code. In this
case, efforts were made to determine the appropriate SIC codes
-associated with the emissions. However, if that was hot
possible, the data were not used in the analysis. Other
3-9
-------
reference sources provided additional potential emission source
categories that may not have been included in TRI.6
Table 3-3 presents a compilation of SIC codes that have been
associated with mercury emissions.5'6 This table lists the SIC
codes that were identified as a potential source of mercury
emissions, provides a description of the SIC code, and identifies
other emission sources that do not have an assigned SIC code.5'6
Table 3-4 provides a summary of the estimated 1990
nationwide mercury emissions for those source categories where
adequate information was available (i.e., emission factors and
production data). Appendix A presents the data used for each of
these estimates, assumptions, and the emission calculations for
each of these source categories. The estimated emissions were
based on emission factors provided in this document or calculated
from source test data and appropriate process information, if
available.
The total 1990 nationwide mercury emissions estimate was
302 Mg (332 tons) for those source categories identified in
Table 3-4. The five specific sources emitting the largest
quantities of mercury were coal combustion (111 Mg; 122 tons) ,
medical waste incineration (59 Mg; 65 tons), municipal waste
combustion (58 Mg; 64 tons), oil combustion (14 Mg; 15 tons), and
paint application (13 Mg, 15 tons). These five specific sources
combined accounted for approximately 84 percent of the total
mercury emissions in Table 3-4.
Of the five major source categories, mercury emissions
resulting from combustion sources accounted for a total of 243 Mg
(268 tons) or approximately 80 percent of the total estimated
emissions. Within the combustion source category, the major
contributor to mercury emissions was from the combustion of coal,
followed by municipal waste, and medical waste. Coal combustion
accounted for 46 percent of the total emissions from combustion
3-10
-------
TABLE 3-3. POTENTIAL SOURCE CATEGORIES OF MERCURY EMISSIONS
SIC Code
Description
0721
1021
1031
1099
12
1221
1222
1311
2611
2621
2812
2813
2816
2819
2821
2822
2833
2834
2842
2851
286
2865
2869
2873
2879
2892
2911
2951
2952
308
3087
32
3229
Crop planting and protecting
Copper ores
Lead and zinc ores
Metal ores
COAL MINING
Bituminous coal and lignite surface
Bituminous coal underground
Oil shale retorting
Pulp mills
Paper mills
Alkalines and chlorine
Industrial gases
Inorganic pigments
Industrial inorganic chemicals
Plastic materials and resins
Synthetic rubber
Medicinals and botanicals
Pharmaceutical preparations
Polishes and sanitation goods
Points and allied products
Industrial organic chemicals
Cyclic crudes and intermediates
Industrial organic chemicals
Nitrogenous fertilizers
Agricultural chemicals
Explosives
Petroleum refining
Asphalt paving mixtures and blocks
Asphalt felts and coatings.
' Miscellaneous plastics products
Custom compound purchased resins
STONE, CLAY. AND GLASS PRODUCTS
Pressed and blown glass
3-11
-------
TABLE 3-3. (continued)
SIC Code
Description
3241
3274
3312
3313
332
3321
3331
3339
3341
3366
3465
3469
3471
3499
36
361
3629
364
3641
3643
3674
3679
3691
3692
3699
3711
38
3821
3822
3829
3841
40
4911
Cement, hydraulic
Lime
Blast furnaces and steel mills
Ferroalloy production
Iron and steel foundries
Gray and ductile iron foundries
Primary copper
Primary nonferrous metals
Secondary nonferrous metals
Copper foundries
Automotive stampings
Non-ferrous foundries
Plating and polishing
Fabricated metal products
ELECTRONIC AND OTHER ELECTRIC EQUIPMENT
Electric transmission and distribution equipment
Electrical industrial apparatus .
Electric lighting and wiring equipment
Electric lamps
Current-carrying wiring devices
Semiconductors and related devices
Electronic components
Storage batteries
Primary batteries, dry and wet
Electrical equipment and supplies
Motor vehicles and car bodies
INSTRUMENTS AND RELATED PRODUCTS
Laboratory apparatus and furniture
Environmental controls
Measuring and controlling devices
Surgical and medical instruments
RAILROAD TRANSPORTATION
Electric services -
3-12
-------
TABLE 3-3. (continued)
SIC Code
Description
4941
4952
4953
5094
SO
8021
8221
8731
9223
9511
9661
9711
Water supply
Sewerage systems
Refuse systems (includes municipal waste combustion, sewage sludge
incineration, and medical waste incineration)
Jewelry and precious stones
HEALTH SERVICES
Offices and clinics of dentists
Colleges and universities
Commercial physical research
Correctional institutions
Air, water, and solid waste management
Space research and technology
National security
Coal combustion
General laboratory use
Natural gas combustion
Oil combustion
Wood combustion
Source: References 5 and fi.
3-13
-------
TABLE 3-4. ESTIMATED 1990 NATIONWIDE MERCURY EMISSIONS
FOR SELECTED SOURCE CATEGORIES
Source category
Mercury and mercury compound
' production
Primary mercury production
Secondary mercury production
Mercury compound production
Maior uses of mercury
Chlor-alkali production
Battery manufacture
Electrical uses
Combustion sources
Coal combustion
Oil combustion
Natural gas combustion
Municipal waste combustion
Sewage sludge combustion
• Medical waste combustion
Wood combustion
Miscellaneous manufacturing
processes
Portland cement production
Lime manufacturing
Carbon black production
Byproduct coke production
Primary lead smelting
Primary copper smelting
Petroleum refining
Oil shale retorting
Geothermal power plants
Other miscellaneous sources
Mercury catalysts
Dental alloys
Mobile sources
Crematories
Paint
TOTAL
Mercury
Mg/yr
NA
5.7
NA
9.3
0.1
9.0
111
13.5
0
57.9
1.6
58.7
0.3
5.6
0.6
0.2
NA
8.2
NA
NA
0
1.3
0
0.5
4.5
0.4
13.2
302
emissions
Tons/yr
6.3
10.2
0.1
9.9
122
14.9
0
63.8
1.8
64.7
0.3
6.2
0.7
0.2
9.0
0
1.4
0
0.6
5.0
0.4
14.6
332
Basis
No emission factors
Appendix A
No emission factors
Appendix A
Appendix A
Appendix A
Appendix A
Appendix A
No emission factor
Appendix A
Appendix A
Appendix A
Appendix A
Appendix A
Appendix A
Appendix A
No emission factor
Appendix A
No emission factor
No emission factor
Appendix A
Appendix A
Appendix A
Appendix A
Appendix A
Appendix A
Appendix A
NA = Non-applicable
3-14
-------
sources and 37 percent of the total emissions from all source
categories. The other five combustion sources, wood, municipal
waste, medical waste, sewage sludge, and oil, collectively
accounted for 54 percent of the total emissions from combustion
sources and 44 percent of the total emissions from all source
categories. The paint category was the only other source
category to show estimated mercury emissions greater than 10 Mg
(11 tons).
3-15
-------
SECTION 4
EMISSIONS FROM MERCURY PRODUCTION
In 1991, the total supply of metallic mercury (Hg) in the
United States was 1,416 Mg (1,558 tons).7 Of this total,
approximately 51 percent was from depletion of the former mercury
ore producer stockpile and mercury production as a byproduct of
gold ore mining. Approximately 24 percent resulted from
secondary production processes (reclamation); the remaining
25 percent was due to change in industry stocks, Government
stockpile excesses, and imports (see Section 3, Figure 3-1).
There were 13 facilities in the United States that produced
mercury, primarily on the East Coast and in the West. Of these
facilities, eight produced mercury as a byproduct from gold ore
and five were mercury reclaimers. Emissions of mercury occur
primarily during the metal production process and during mercury
reclamation processes.
This section presents information on the identification of
the producers and descriptions of typical production processes.
Process flow diagrams are given as appropriate, and any known
emission control practices are presented. Estimates of mercury
emissions are provided in the form of emission factors wherever
data were available.
4.1 PRIMARY MERCURY PRODUCTION
Mercury is currently produced in the U.S. only as a
byproduct from the mining of gold ores. Production from mercury
ore had occurred at the McDermitt Mine in McDermitt, Nevada, but
the mine ceased operation in.1990. During the past 2 years, the
equipment has been dismantled and sold, landfilled, or scrapped,
4-1
-------
and all major buildings have been removed. In 1991, eight U.S.
gold mines produced metallic mercury as a byproduct; Table 4-1
presents a list of these gold mines.7 As shown in the table, six
of the mines are in Nevada, one is in California, and one is in
Utah. None of the operating gold mines in Alaska produce
byproduct mercury. In 1991, the quantity of mercury recovered at
these mines was reported by the Bureau of Mines to be 58 Mg (64
tons).
4.1.1 Process Description
Production from Mercury Ores--
No process description of the McDermitt Mine operation will
be presented because the existing equipment has been removed from
the site, thereby negating any possibility that the facility
could reopen at a future date using the same process and
equipment.
*
Byproduct from Gold Ores--
Since the closure of the McDermitt Mine, recovery of mercury
as a byproduct from gold ores is the only remaining ore-based
production process. All other processes for mercury production
are either reclamation or government surplus stock. A simplified
flow diagram depicting mercury recovery from a gold cyanidation
process is shown in Figure 4-1.
The incoming gold ore is crushed using a series of jaw
crushers, cone crushers, and ball mills. If the incoming ore is
an oxide-based ore, no pretreatment is required, and the crushed
ore is mixed with water and sent to the classifier. If the ore
is a sulfide-based ore, it must be pretreated using either a
fluid-bed or multiple hearth pretreatment furnace (roaster) to
a
convert metallic sulfides to metallic oxides. The exhaust gas
from either of these units is sent through wet electrostatic
precipitatbrs (ESP's) and, if necessary, through carbon
condensers. The exhaust gas then passes through a scrubber in
4-2
-------
TABLE 4-1. BYPRODUCT MERCURY-PRODUCING GOLD MINES IN
THE UNITED STATES IN 1991
Mine
Getchell
Carlin Mines Complex
Hog Ranch
Jerritt Canyon
(Enfield Bell)
Mclaughlin
Mercur
Paradise Peak
Pinson and Kramer Hill
County and
State
Humboldt, NV
Eureka, NV
Washoe, NV
Elko, NV
Napa, CA
Tooele, UT
Nye, NV
Humboldt, NV
Operator
FMC Gold Co.
Newmont Gold Co.
Western Hog Ranch Co.
Independence Mining Co., Inc.
Homestake Mining Co.
Barrick Mercur Gold Mines, Inc.
FMC Gold Co.
Pinson Mining Co.
Source: Reference 7.
4-3
-------
•**
I
CMC—*
•POTENTIAL MERCURY EMISSION SOURCES
Figure 4-1. Major components of mercury recovery from gold ores.
-------
which S02 is removed by lime prior to discharging to the
atmosphere. If the treated sulfide ore is high in mercury
content, the primary mercury recovery process occurs from the wet
ESP's. If the concentration is sufficiently low, no attempt is
made to recover the mercury for sale. The pretreated ore is
mixed with water and sent to the classifier, where the ore is
separated (classified) according t^ size. Ore pieces too large
to continue in the process are returned to the crusher operation.
From the classifier, the slurry passes through a
concentrator to reduce the water content and then to a series of
agitators containing the cyanide leach solution. From the
agitators, the slurry is filtered, the filter cake sent to
disposal, and the filtrate containing the^gold and mercury is
transferred to the electrowinning process. If the carbon-in-pulp
(CIP) process is used, the cyanide pulp in the agitators is
treated with activated carbon to adsorb the gold and mercury.
The carbon is filtered from the agitator tanks and treated with
an alkaline cyanide-alcohol solution to desorb the metals. This
liquid is then transferred to the electrowinning tanks. In the
electrowinning process, the gold and mercury are electrodeposited
onto a stainless steel wool cathode, which is sent to a retort to
remove mercury and other volatile impurities. The stainless
steel wool containing the gold is transferred from the retort to
a separate smelting furnace where the gold is melted and
recovered as crude bullion.
The exhaust gas from the retort, containing mercury, SO2,
particulate, water vapor, and other volatile components, passes
through condenser tubes where the mercury condenses as a liquid
and is collected under water in the launders. From the launders,
the mercury is purified and sent to storage. After passing
through the condenser tubes, the exhaust gas goes through a
venturi and impinger tower to remove particulate and water
droplets and then moves through the S02 scrubber prior to
discharging to the atmosphere.
4-5
-------
Gold ores in open heaps and dumps can also be treated by
cyanide leaching. In this process, the gold ore is placed on a
leaching pad and sprayed with the cyanide solution. The solution
permeates down through the ore to a collection system on the pad,
and the resulting pregnant solution is sent to a solution pond.
From this pond, the leachate liquors, which contain gold and
mercury, are transferred t^ the gold recovery area where the
liquor is filtered and sent to the electrowinning process.
4.1.2 Emission Control' Measures
Potential sources of mercury emissions from gold processing
facilities are at locations where furnaces, retorts, or other
high, temperature sources are used_ in the process and where the
mercury is removed from the launders. The treated gas discharged
to the atmosphere is also a source of mercury emissions. These
sources are denoted in Figure 4-1 with a solid circle.
When pretreatment roasting is required, the exhaust gases
from the furnace pass through a cyclone to remove particulate and
then move through wet ESP's to remove arsenic, mercury, and some
of the 862 - If the mercury concentration in the gold ore is
high, the ESP's will not remove all of the mercury, and an
activated carbon adsorber bed may be required for additional
mercury removal. The gas passes through a lime scrubber to
remove SC^; if the SO2 concentration is low, a caustic scrubber
may be used.8 From the scrubber, the gas is discharged through
the stack to the atmosphere. Essentially the same emission
control measures are used from the exhaust gas from the retort.
After the gas passes through the condenser tubes to remove the
mercury, a venturi and a cyclone are used to remove particulate
and water droplets. These controls are followed by the lime
scrubber to remove the S02 prior to discharging the clean gas to
the atmosphere.
4-6
-------
4.1.3 Emissions
The major sources of mercury emissions for gold processing
facilities are the pretreatment roaster (if required) and the
retort. Other sources of emissions are from the purification
process after removal of mercury from the launders and the stack
emissions to the atmosphere. No emissions data have been
published for facilities producing mercury as a byproduct from
gold ore. Furthermore, limited data were published for emission
sources at facilities that produced mercury from the primary ore.
Emission factors for three potential sources in the production
process from mercury ore were published in 1973. These emission
factors are presented in Table 4-2 and were based on the quantity
of ore processed, not on the quantity of mercury produced. No
information was provided to equate the quantity of ore processed
to quantity of mercury produced.1(^
TABLE 4-2. MERCURY EMISSION FACTORS FOR PRIMARY MERCURY
PRODUCTION
Process
Cleaning launders
Retort nneratinn
Stack
Emission
kg/Mg ore
0.01
n.nni
0.16
factor
Ib/ton ore
0.02
nnn?
0.32
Notes
Uncontrolled emissions3
1 Incnrvtrnlforl Amiccinnc"
Uncontrolled emissions3
3 As stated in Reference 9.
Source: Reference 9.
Emission tests were conducted in the condenser stack at the
McDermitt Mine in 1981, and the average mercury emission rate was
calculated to be 816 grams/day (g/d) [1.8 pounds/day (lb/d)].
Based on eight furnace runs per year, each of 15 days duration,
and a production of 750 tons of mercury in 1981, the calculated
emission rate would be 0.13 kg/Mg (0.3 Ib/ton) of mercury
produced.
11
The emission factors shown in Table 4-2 are based on
tons of ore processed, whereas the rate calculated from the
emission tests at McDermitt Mine is based on tons of mercury
produced.
4-7
-------
Extreme caution should be exercised in using any of these
emission factors from primary mercury production for mercury
production as a byproduct of gold mining. The treatment
techniques to recover the mercury, after the mercury has been
vaporized in a retort or furnace, and the emission sources are
very similar for both processes, but the overall production
process is different.
4.2 SECONDARY MERCURY PRODUCTION
Secondary mercury production involves the processing of
scrapped mercury-containing products, industrial waste and scrap,
and scrap mercury from Government stocks. Major sources of
recycled mercury include dental amalgams and scrap mercury from
instrument and electrical manufacturers (lamps and switches),
wastes and sludges from research laboratories and electrolytic
refining plants, and mercury batteries.2
In 1991, 122 Mg (134 tons) of mercury was recycled from
industrial scrap and 215 Mg (237 tons) from Government stocks.7
These totals do not include in-house mercury reclamation at
industrial plants using mercury. Table 4-3 presents a list of
the five major companies that were involved in secondary mercury
production (mercury recyclers) in 1989.12
TABLE 4-3. U.S. MERCURY RECYCLERS IN 1989
Adrow Chemical Company Wanaque, NJ
Bethlehem Apparatus Company, Inc. • Hellertown, PA
D. F. Goldsmith Chemical and Metals Corp. Evanston, IL
Mercury Refining Company, Inc. ' Latham, NY
Wood Ridge Chemical Company Newark, NJ
Source: Reference 12.
4-8
-------
4.2.1 Process Description
Secondary mercury production (recycling) can be accomplished
by one of two general methods: chemical treatment or thermal
treatment. Chemical treatment can encompass several methods for
processing aqueous mercury-containing waste streams. To
precipitate metallic mercury, the waste stream can be treated
with sodium borohydride or it can be passed through a zinc-dust
bed. Mercuric sulfide can also be precipitated from the waste
streams by treatment with a water-soluble sulfide, such as sodium
sulfide. Ion-exchange systems can be used to recover ionic
mercury for reuse, while mercuric ions can be trapped by
treatment with chemically modified cellulose.1^
The most common method to recover metallic mercury for
recycling is thermal treatment. . Figure 4-2 provides a general
process diagram for secondary mercury recovery at a battery
plant. This process is generally representative of the recovery
of mercury by thermal treatment of scrap. Generally, the
mercury-containing scrap .is reduced in size and is heated in
retorts or furnaces at about 538°C (1000°F) to vaporize the
mercury. The mercury vapors are condensed by water-cooled
condensers and collected under water.14/1^
Vapors from the condenser, which may contain particulate,
organic compounds, and possibly other volatile materials from the
scrap, are combined with vapors from the mercury collector line.
This combined vapor stream is passed through an aqueous scrubber
to remove particulate and acid gases (e.g., HC1, SC^) . From the
aqueous scrubber, the vapor stream passes through a charcoal
filter to remove organic coniponents prior to discharging into the
atmosphere.14
The collected mercury is further purified by distillation,
collected, and then transferred to the filling area. In the
filling area, special filling devices are used to bottle small
4-9
-------
H,O
. SCRAP ^
,
H
o
Hg
•
1 ^
RETORT
CHAMBER
,
r \
1 V
• 1
CONDENSER
HjO
A
— —
*
/'
'
Hg
^
•
T
^
i !
— >
T 1
SCRUBBER
A
T
1.
DISTILLATION
1
i
1
1
1
! •
Cp— -^ CHARCOAL
^ FILTERS
A
f
1.
FILLING AREA
Hg COLLECTOR
DENOTES POTENTIAL MERCURY EMISSION SOURCE
Figure 4-2. Process flow diagram for secondary recovery at a battery plant.
-------
quantities, usually 0.464 kg (1 Ib) or 2.3 kg (5 Ib) of distilled
mercury. With these filling devices, the mercury flows by
gravity through tubing from a holding tank into the flask until
the flask overflows into an overflow bottle. The desired amount
of mercury is dispensed into the shipping bottle by opening a
valve at the bottom of the flask. The shipping bottle is then
immediately .capped after the filling and sent to the storage
area.15
4.2.2 Emission Control Measures
Information on specific emission control measures is very
limited and site specific. If a scrubber is used, as shown in
Figure 4-2, mercury vapor or droplets in the exhaust gas may be
removed by condensation in the spray. There is no information to
indicate that chemical filters would be effective in removing
mercury vapors.15 No information was found for other control
measures that are being used in secondary mercury production
processes. Concentrations in the workroom air due to mercury
vapor emissions from the hot retort may be reduced by the
following methods: containment, local exhaust ventilation,
dilution ventilation, isolation, and./G2f pei'scnal protective
equipment. No information was provided to indicate that these
systems are followed by any type of emission control device.15
Vapor emissions due to mercury transfer during the distillation
or filling stages may be reduced by containment, ventilation
(local exhaust or ventilation), or temperature control.
4.2.3 Emissions
During secondary mercury production, emissions may
potentially occur from the following sources: retort or furnace
operations, distillation, and discharge to the atmosphere from
the charcoal filters.14'15 The major mercury emission sources
are due to condenser exhaust and vapor emissions that occur
during unloading of the retort chamber. These sources are
4-11
-------
indicated in Figure 4-2 by a solid circle. Mercury emissions can
also occur in the filling area when the flask overflows and
during the bottling process.
The secondary mercury production process has not undergone
any recent emission tests so there is virtually no data for this
process. .In 1973, emission factors were estimated to be 20 kg
(40 Ib) per megagram (ton) of mercury processed due to
uncontrolled emissions over the entire process.^ These data
should be used with extreme caution because they are very old and
industry practices have changed.
Data for emission levels in a limited number of facilities
have been reported.14 For example, a Pennsylvania recycler used
a water spray to control mercury emissions from the condenser
exhaust. Mercury emissions after the spray were
840 g/d (1.85 Ib/d). A New York plant was estimated to emit less
than 1 g/d (<0.002 Ib/d) to the atmosphere.14 However, these
data, in terms of weight of mercury emitted per day, are not
useful for developing emission factors because no process or
production data were available for these facilities.
The only mercury emission data reported in the 1990 TRI was
for Mercury Refining Company, Inc., in Albany (Latham), New
York.5 This facility reported plant emissions to the atmosphere
of 227 kg (500 Ib) for 1990.
4.3 MERCURY COMPOUNDS PRODUCTION
The production of mercury compounds presents a potential
source of release of mercury into the atmosphere. Table 4-4
lists several producers of inorganic and organic mercury
compounds. Only one facility reported significant mercury
emissions in the 1990 TRI: Mallinkrodt Specialty Chemicals Co.
in Erie, PA reported 226.8 kg (500 Ib).5'16 - -
4-12
-------
TABLE 4-4. MERCURY COMPOUND PRODUCERS
Producer
Location
Compound(s)
Atochem North America, Inc., Chemical Tulsa, OK
Specialties Division
Atomergic Chemetals Corp. Farmingdale,NY
Cambrex Corp., CasChem, Inc., Subsidiary Carlstadt, NJ
(formerly Cosan Chem. Corp.)
W.A. Cleary Corp.
Deepwater, Inc.
GFS Chemicals, Inc.
Somerset, NJ
Carson, CA
Columbus, OH
Huls America, Inc. Elizabeth, NJ
Imsera Group, Inc., Erie, PA
Mallinkrodt Inc.,
Subsidiary, Mallinkrodt Specialty Chem. Co.
Morton International, Inc., Specialty Woburn, MA
Chemicals Group, Advanced Materials, CVD
Inc. Subsidiary
Polychemical Laboratories, Inc.
R.S.A Corporation
Troy Chemical Corp.
Melville, NY
Ardsley, NY
Newark, NJ
HgF2
Thimerosal (Merthiolate)
Phenylmercury acetate
(PMA), Phenylmercury
oleate
PMA
Hgl2
HgBr2, HgU, Hg(NO3)2,
HgS04
PMA
HgCI2 on carbon support
(catalyst for vinyl chloride
manufacture)
Highly purified
dimethylmercury,
(CH3>2Hg, for chemical
vapor deposition (CVD) of
thin films
Thimerosal (Merthiolate)
Hg(SCN)2
PMA
Source: Reference 16.
4.3.1 Process Description
Numerous inorganic mercury compounds are produced annually
in the U.S. using metallic mercury as the starting material. The
production processes for mercuric chloride and mercuric oxide
were selected to serve as typical examples because both of these
compounds are common mercury compounds that are annually produced
in large quantities. The production processes for each compound
have been studied at Troy Chemical Corporation.17 Phenylmercurie
.acetate is one of the most common organomercuric- compounds
produced in the U.S. The production method for this compound was
also selected as a typical process because of the.quantities
produced, and the process has been studied.17 A synopsis of
4-13
-------
these three production processes is provided below; additional
information is provided in Reference 15.
Mercuric Chloride and Mercurous Chloride--
The production of these two compounds- occurs by the direct
reaction of mercury with chlorine gas according to the following
equations:
2Hg° + C12 •* Hg2Cl2
Hg° + C12 •* HgCl2
Figure 4-3 presents a process diagram for the production of
mercuric chloride. Elemental mercury (Stream A) is pumped from a
holding tank into a reactor where it reacts with excess chlorine
gas (Stream B). The reaction products (Stream C)'are ducted to a
precipitation unit where the dry product (HgCl2) settles and is
raked out. Mercuric chloride (Stream D) is packaged and sealed
in drums for shipping.1^'17 The exhaust from the reactor
(Stream E) is sent to a caustic scrubber where unreacted mercury
is recovered and is then recycled back (Stream F) to the reactor.
A similar process is used to produce mercurous chloride.
Mercuric Oxide--
Two different processes have been used for mercuric oxide
production: (1) production via mercuric chloride and
(2) production via mercuric nitrate intermediates. Both
processes are shown in Figure 4-4.
In production via mercuric chloride, mercury (Stream A) and
chlorine in brine solution (Stream B) are mixed in a
reactor where mercuric chloride is produced in solution by
oxidation of the liquid mercury. The mercuric chloride
(Stream C) is then transferred to a second reactor and an aqueous
caustic (NaOH) solution is added, resulting in the formation of
4-14
-------
I
H
U1
VENT TO AIR 01%
Hg
NaOH
CARBON
FILTER
Hg-
t
EXCESS
CI2 ' B
SCRUBBER
EXHAUST HOOD
REACTOR
(COMBUSTION)
T
HEAT
PRECIPITATION
UNIT
DRUMMING
-HgCI2
WASTE EFFLUENT
NaOCI + Nad
(1.9% OF ORIGINAL
AMOUNT OF HG
RECYCLED)
Figure 4-3. Mercuric/mercurous chloride production.
-------
Reactor 1:
Oxidation
toHgCI2
C
r
Reactor 2:
Precipitation
asHgO
0
Washing
Drying
Screening
Packaging
NaOH
A
Hfl —
a\
»
Reactor 1:
Formation
o»Hg(N03)2
N
C
P
aOH
Reactor 2:
Precipitation
oIHgO
Filtration
ofCryst Red
Oxide or
Powd. Yellow
Oxide
0
Drumming
WetHgO
Cake
t
Oven
Drying
Enclosed
Dumping
Station
Filtrate
Mercury
Effluent
Treatment
System
i
Grinder
_Vacuum_
Feeding"
Packaging
inSO-lb
Drum*
Denotes potential mercury emission source
Figure 4-4. Mercuric oxide production via mercuric chloride and mercuric
nitrate intermediates.
-------
mercuric oxide. The mercuric oxide precipitate (Stream D) is
then washed, dried, screened, and packaged.14
In the process using the mercuric nitrate intermediate,
(also shown in Figure 4-4), mercury (Stream A) and nitric acid
(Stream B) are combined in a reactor, resulting in the formation
of mercuric nitrate (Hg(N03)2). The mercuric nitrate (Stream C)
is then transferred to a second reactor where mercuric oxide is
precipitated by adding an aqueous caustic solution (NaOH) . The
mercuric oxide (Stream D) is washed, dried, ground, and
packaged."
Phenylmercuric Acetate --
Phenylmercuric acetate (PMA) can be produced by one of two
processes. In the most common production process, mercuric oxide
is transferred to a glass -lined reactor and refluxed in a boiling
mixture of acetic acid (CH3C02H) and benzene (CgHg) at
approximately 80 °C (176°F) . The reaction proceeds according to
the following steps:
HgO + 2CH3C02H -* (CH3C02)2Hg + H20
(CH3C02)2Hg + CgHg -> CgH5Hg02CCH3 + CH3C02H
Figure 4-5 presents a process flow diagram for this PMA
production process using 1982 technology, which is the most
recent available description.1^
In the less common process, mercuric acetate is refluxed
with a mixture of benzene and acetic acid. Aside from the
initial reactions to form the PMA, the subsequent processes
follow the same procedure.
When the reaction is complete, the PMA solution is filtered
to remove any solid material, transferred to a precipitator, and
the solid PMA is filtered to yield a wet filter cake. The wet
PMA filter cake is transported to a vacuum drying oven to produce
4-17
-------
£>
i
H
CD
MERCURY
OXIDE
BFN7FNF
AND ACETIC
ACID
FILTER
/.
\
\ t.
REACTOR f. FILTER » PRECIPITATOR VACUUM ^ fipiNpFR ^ DRUM FOR
OVEN " SHIPMENT
- ^
,
Figure 4-5. Process flow diagram for production of phenylmercuric acetate.
-------
the final dry product. After drying, the PMA is ground and
packed in fiber drums for shipment.
4.3.2 Emission Control Measures
No information was found on specific emission control
devices to remove or treat the mercury emissions. Only methods
designed to reduce the workplace concentrations without
subsequent treatment were presented.15 Methods suitable for
reducing workroom air concentrations of mercury -during the
production of mercury compounds are similar to those described
for primary and secondary mercury processing. Particulate
concentrations in the workplace resulting from several process
operations (e.g., addition of dry chemicals to reactors,
• •
•filtration, drying, grinding, and packaging) may be reduced by
containment, exhaust ventilation, dilution ventilation, and
personal protective equipment. Vapor concentrations from
reactors may be reduced by containment. Mercury vapor
concentrations in the workplace from mercury transfer to reactors
may be reduced by containment.15
In the production and packaging of PMA, local exhaust
ventilation is used to reduce mercury concentrations in workroom
air at the loading hopper for the grinder, at the station where
the dried PMA is drummed, and at the drum loading stand where PMA
exits the grinder. Local exhaust ventilation is used at the
reactor charging station and at the blender, where dilute PMA is
discharged.15
During mercuric oxide production, grinding and packaging
operations are done in an enclosed system under vacuum, including
material transfers. A cyclone dust collector separates fine dust
from product-sized HgO particles, which are channeled to the
packaging station. The fine dust is collected and transferred
periodically to fiber drums. The vacuum pump discharge also goes
4-19
-------
through a cyclone dust separator before it exhausts to the roof.
Collected dust is recycled through the grinder.17
4.3.3 Emissions
During the production of these compounds, emissions of
mercury vapor and particulate mercury compounds may occur at the
following sources: reactors, driers, filters, grinders, and
transfer operations. These emission sources are indicated in
Figures 4-3, 4-4, and 4-5 by a solid circle.
Emission factors are not available for production of mercury
compounds. No test data for mercury emissions were found that
would permit the calculation of emission factors.
4-20
-------
SECTION 5
EMISSIONS FROM MAJOR USES OF MERCURY
Emissions from industrial processes that use mercury are
discussed in this section. Based on the 1991 U.S. industrial
demand figures presented in Figure 3-1 in Section 3, mercury has
four major commercial uses. These are: (1) chlor-alkali
production using the mercury cell process, (2) primary battery
production, (3) production of measuring and control instruments,
and (4) production of electrical lighting, wiring devices, and
electrical switches. This section is divided into four
subsections, one devoted to each major use. Each of the
subsections presents a general discussion of the production
process and where mercury is used in the process, descriptions of
existing mercury emission control measures, and estimates of
mercury emission factors. The level of detail will vary
according to the availability of information, particularly for
emissions where data may be incomplete or absent.
5.1 CHLOR-ALKALI PRODUCTION USING THE MERCURY CELL PROCESS
In 1988, the mercury cell process accounted for 17 percent
of all U.S. chlorine production. The diaphragm cell accounted
for 76 percent, the membrane cell for 5 percent, and other
methods for 2 percent. However, recent trends are moving away
from mercury cell production toward the more environmentally
acceptable membrane cell process. Only the mercury cell process
uses mercury. The more modern membrane cell process is more
energy efficient compared to the diaphragm cell or mercury cell
and produces a higher quality product.1** Table 5-1 presents the
5-1
-------
TABLE 5-1. 1990 MERCURY CELL CHLOR-ALKALI PRODUCTION FACILITIES
FACILITY
Akzo Chemicals, Inc.
Georgia-Pacific Corp., Chemical
Division
BF Goodrich, Chemical Division
Hanlin Group, Inc., LCP Chemicals
Division
Lin Chem, Inc.
Occidental Petroleum Corporation,
Electrochemicals Division
Olin Corporation,
Olin Chemicals
Pioneer Chlor-alkali Company, Inc.
PPG Industries, Inc.,
Chemicals Group
Vulcan Materials Company, Vulcan
Chemicals Division
LOCATION
Le Moyne, AL
Bellingham, WA
Calvert City, KY
Acme, NC
Brunswick, GA
Moundsville, WV
Orrington, ME
Ashtabula, OH
Deer Park, TX
Delaware City, DE
Mobile, AL
Mussel! Shoals, AL
Augusta, GA
Charleston, TN
St. Gabriel, LA
Lake Charles, LA
Natrium, WV
Port Edwards, Wl
TOTAL
CAPACITY,
103 Mg/yr
70
82
109
48
96
79
76
36
347
126
34
132
102
230
160
1,041
313
65
3,146
103 TONS/YR
78
90
120
53
106
87
80
40
383
139
37
146
112
254
176
1,148
345
72
3,466
Source: Reference 16.
5-2
-------
location and capacity of mercury cell chlor-alkali production
facilities operating in 1991. 16
5.1.1 Process
The mercury cell process consists of two electrochemical
cells, the electrolyzer and the decomposer. A basic flow diagram
for a mercury cell chlor-alkali production operation is shown in
Figure 5-1.
Saturated (25.5 weight percent) purified sodium or potassium
brine (Stream A) flows from the main brine saturation section,
through the inlet end box, and into the electrolyzer cell. The
cell is an elongated trough that is inclined approximately 1° to
2.5° with sides that are typically lined with rubber. Stationary
activated titanium anodes are suspended from above into the
brine; mercury, which is the cathode, flows concurrently with the
brine over a steel base.
The electrochemical reaction that occurs at the titanium
anodes is shown in equation (1) ; the reaction at the mercury
cathode
shown in equation (3) .
c shown in equation (2) ,- and £he overall reaction is
2C1" -» Cl2t -(- 2e (1)
Hg + 2Na+ + 2e -» Na-Hg amalgam (2)
Hg + 2Na+ + 2C1" •* Cl2t + Na-Hg amalgam (3)
Chlorine gas (Stream B) , formed at the electrplyzer anode,
\
is collected for further treatment. The spent brine (Stream C)
contains 21-22 weight percent NaCl and is recycled from the -
electrolyzer to the main brine saturation section through a
dechlorination stage. Sodium forms an amalgam, containing from
0.25 to 0.5 percent sodium, at the electrolyzer cathode. The
resulting amalgam flows into the outlet end box at the end of the
electrolyzer. In the outlet end box, the amalgam is constantly
5-3
-------
BASIC TREATMENT CHEMCAU
(SODA ASH. CAUSTIC LUC.
ACID. CaCL2. ETC.)
CHLORINE
PRODUCT
CHLORINE
SOLID
NjCL FEED
OTHER
1
BRINE
OECHLORINATOR
SPENT 3R1NE
MAIN MINE
SATURATION.
PURIFICATION. AND
FILTRATION
TREATED (A)
BRINE
H
(B)
COOUNO.
DRYING.
COMPRESSION. ANO
LIQUEFACTION
(C)
ENO-BOX
VENTILATIOIf SY5T
OUTLET END-BOX
ENO-ipX
VENTILATION SYSTEM
ENO-80X
VEjmUTIOIt SYSTCM
denotes potential
mercury emissions
WATER COLLECnOII
SYSTEM
END-MI
VENTILATION SYSTEM
HYDROGEN
^ GAS
BYPRODUCT
CAUSTIC SODA
SOLUTION
» TICK. AM) J-CAUSTIC
KfPUMP
Figure 5-1. Basic flow diagram for a mercury-cell
chlor-alkali operation.^
5-4
-------
covered with an aqueous layer to reduce mercury emissions. The
outlet end box also allows removal of a thick mercury "butter"
that is formed by impurities. The sodium amalgam (Stream D)
flows from the outlet end box into the second cell, the
decomposer.
The decomposer is a short-circuited electrical cell in which
the sodium amalgam acts as the anode and graphite as the cathode
in sodium hydroxide solution. Fresh water is added to the
decomposer where it reacts with the sodium amalgam to produce
elemental mercury (Stream E), sodium hydroxide (Stream F), and
byproduct hydrogen gas (Stream G). Stream E is then stripped of
sodium and the mercury (Stream H) is recirculated back to the
electrolyzer through the inlet end box. The inlet end box
provides a convenient receptacle on the inlet end of the
electrolyzer to receive the recycled mercury from the decomposer
and keep it covered with an aqueous layer to reduce mercury
emissions.
The caustic soda solution (Stream F) leaving the decomposer
at a typical concentration of 50 weight percent is filtered and
then further concentrated by evaporation. The byproduct hydrogen
gas (Stream G) may be vented to the atmosphere, burned as a fuel,
or used as a feed material for other processes.
5.1.2 Emission Control Measures14
Several control techniques can be employed to reduce the
level of mercury in the hydrogen streams and in the ventilation
stream from the end boxes. The most commonly used techniques
are: (1) gas stream cooling, (2) mist eliminators,
(3) scrubbers, and (4) adsorption on activated carbon or
molecular sieves. Mercury vapor concentrations in the cell room
air are not subject to specific emission control measures but
rather are maintained at acceptable worker exposure levels using
good housekeeping, practices and equipment maintenance procedures.
5-5
-------
Gas stream cooling may be used as the primary mercury
control technique or as a preliminary removal step to be followed
by a more efficient control device. The hydrogen gas stream from
the decomposer exits the decomposer at 93° to 127°C (200° to
260°F) and passes into a primary cooler. In this indirect
cooler, a shell-and-tube heat exchanger, ambient temperature
water is used to cool the gas stream to 32° to 43°C (90° to
110°F). A knockout container following the cooler is used to
collect the mercury. If additional mercury removal is desired,
the gas stream may be passed through a more efficient cooler or
another device. Direct or indirect coolers using chilled water
or brine provide for more efficient mercury removal by decreasing
the temperature of the gas stream to 3° to 13 °C (37° to 55°F).
If the gas stream is passed directly through a chilled water or
brine solution, the mercury condenses and is collected under
water or brine in lined containers. Mercury in the ventilation
air from the end boxes can be removed using either direct or
indirect cooling methods, but the direct method is used more
frequently because the ventilation air from the exit end box
contains mercuric chloride particulate. The direct cooling
method not only cools the gas stream, but also removes the
particulate from the stream. Regardless of the gas stream
treated, the water or brine from direct contact coolers requires
water treatment prior to reuse or discharge because of the
dissolved mercury in the liquid.
Mist eliminators can be used to removed mercury droplets,
water droplets, or particulate from the cooled gas streams. The
most common type of eliminator used is a fiber pad enclosed by
screens. With the fiber pad eliminator, trapped particles are
removed by periodic spray washing of the pad and collection and
treatment of the spray solution.
Scrubbers are used to chemically absorb the mercury from
both the hydrogen stream and the end box ventilation streams.
The scrubbing solution is either depleted brine from the mercury
5-6
-------
cell or a sodium hypochlorite (NaOCl) solution. These solutions
are used in either sieve plate scrubbing towers or packed-bed
scrubbers. Mercury vapor and mist react with the sodium chloride
or hypochlorite scrubbing solution to form water-soluble mercury
complexes. If depleted brine is used, the brine solution is
transferred from the scrubber to the mercury cell where it is
mixed with fresh brine and the mercury is recovered by
electrolysis in the cell.
Sulfur- and iodine-impregnated carbon adsorption systems are
commonly used as a method to reduce the mercury levels in the
hydrogen gas stream. Use of this method requires pretreatment of
the gas stream by primary or secondary cooling followed by mist
eliminators to remove about 90 percent of the mercury content of
the gas stream. As the gas stream passes through the carbon
adsorber, the mercury vapor is initially adsorbed by the carbon
and then reacts with the sulfur or iodine to form the
corresponding mercury sulfides or iodides. Depending upon the
purity requirements and final use for the hydrogen gas, several"
adsorber beds may be connected in series to reduce the mercury
levels to the very low parts per billion (ppb) range.
A proprietary molecular sieve adsorbant was used by five
facilities to remove mercury from the hydrogen gas stream until
1984 when the supply of the adsorbant was discontinued by the
manufacturer. The technique used dual adsorption beds in
parallel such that while one bed was being used for adsorption,
the other was being regenerated. A portion of the purified
hydrogen gas from one adsorption bed was diverted, heated, and
used to regenerate the second adsorption bed.
5.1.3 Emissions
The three primary sources of mercury emissions to the air
are:.- (l) the byproduct hydrogen stream, (2) end box ventilation
5-7
-------
air, and (3) cell room ventilation air. Emission sources (1) and
(2) are indicated on Figure 5-1 by solid circles.
The byproduct hydrogen stream from the decomposer is
saturated with mercury vapor and may also contain fine droplets
of liquid mercury. The quantity of mercury emitted in the end
box ventilation air depends on the degree of mercury saturation
and the volumetric flow rate of the air. The amount of mercury
in the cell room ventilation air is variable and comes from many
sources, including end box sampling, removal of mercury butter
from end boxes, maintenance operations, mercury spills, equipment
leaks, cell failure, and other unusual circumstances.14
The only source of data for mercury emissions from chlor-
alkali production facilities was a 1984 EPA report.14 This
report contained test data from 21 chlor-alkali production
facilities. The emission rates presented in Table 5-2 were
calculated based on these test data. Emission control measures
employed at the facilities ranged from no controls to a
combination of control methods. The dates of the emission tests
ranged from 1973 to 1983; however, more recent emission test data
were not available. The emission rates presented in Table 5-2
represent mercury emissions per day. Emission factors were not
calculated using the emission rate data because the chlorine
production rates cited in the report for each of the facilities
appear to be based on process design capacity values rather than
actual production levels during the test. Use of prorated
process design capacity data for daily production rates is not a
reliable method to estimate emission factors.
Of the 21 plants/ only three had production levels in excess
of 364 Mg/d (400 tons/d) and 14 plants had levels between
182-364 Mg/d (200-400 tons/d). Test data for the uncontrolled
emissions from the end box ventilation system were obtained from
the same plant in three different years (19731; 1974, 1977)-. The
data showed approximately an order of magnitude difference in"
5-8
-------
TABLE 5-2. MERCURY EMISSION RATES FOR CHLOR-ALKALI PRODUCTION FACILITIES
Emission source
End box ventilation
system
Hydrogen gas
stream
Controls
Uncontrolled
Scrubber
Cooler/chiller
Scrubber & cooler
Scrubber & carbon adsorber
Scrubber
Cooler/chiller
Cooler & carbon adsorber
Cooler & molecular sieve
Cooler & scrubber
Cooler & molecular sieve & carbon
adsorber
No of
plants
1
5
8
2
1
1
8
4
4
1
1
No of
tests3
3
8
9
2
6
2
14
12
8
1
1
Emission rate, g/d (Ib/d)
Range
23-163
3-549
1-390
2-426
5-118
86-236
1-689
9-159
5-295
59
263
(0.05-0.36)
(0.006-1.21)
(0.003-0.86)
(0.004-0.94)
(0.01-0.26)
(0.19-0.52)
(0.002-1.52)
(0.02-0.35)
(0.01-0.65)
(0.13)
(0.58)
Average
100
200
136
213
32
163
308
73
95
59
263
(0.22)
(0.44)
(0.30)
(0.47)
(0.07)
(0.36)
(0.68)
(0.16)
(0.21)
(0.13)
(0.58)
U1
I
aNumber of tests at each facility ranged from one to seven.
Spurce: Reference 14.
-------
emission rates over the three test years. In 1973, the mercury
emission rate was 163 g/d (0.36 Ib/d) whereas in 1977, the
emission rate was 23 g/d (0.05 Ib/d). No test data were reported
for uncontrolled emissions from the hydrogen gas stream.
The controlled emission rate data often showed a wide
variability depending upon the emission control measure .and the
number of plants tested. In the end box ventilation system
tests, the data presented for the scrubber were affected by a
high emission rate from one facility, which had only one set of
tests. The cited production level for this plant was the lowest
of all plants tested (100 tons/day) so the high value is not a
function of the production level. For the control system using a
cooler followed by a scrubber, one of the two facilities showed a
much higher emission rate (over 2 orders of magnitude) compared
to the other facility. The plant with the higher emission rate
had a lower stated production level (220 tons/d vs. 125 tons/d).
In the hydrogen gas stream tests, the control measure consisting
of a cooler, chiller, refrigerated cooler, or other gas cooling
device, showed a three order of magnitude difference in emission
rates among the eight facilities tested. The facility with the
highest emission rate had a stated production level of 205 Mg/d
(225 tons/d) whereas the facility with the lowest emission rate
had a production level of 273 Mg/d (300 tons/d). The very large
difference in emission rates is obviously not a function of the
stated production levels.
Extreme caution should be exercised in the use of these
rates for specific types of control devices at current mercury
cell production facilities primarily because of the very wide
variability in the emission rates between the plants. This wide
variation does not appear to be a function of production levels
at the plants. Differences between plants in the operation of
the control devices may be a possible explanation. No evaluation
of the variability in the data were presented in the EPA
report.14 A second consideration is that the control techniques
5-10
-------
at the current facilities may be considerably different from the
techniques employed during these tests. In addition, even if the
general technique (e.g., scrubbers, carbon adsorption) at the
current facility is the same, considerable improvements in
control efficiency may have been made since these 'tests were
conducted. Recent test data and information on control measure
system design and efficiency should .be used to evaluate any
current production facility.
5.2 BATTERY MANUFACTURING
Prior to the late 1980's, most primary batteries and some
storage batteries contained mercury in the form of mercuric oxide
(HgO), zinc amalgam (ZnrHg), mercuric chloride (HgCl2)/ or
mercurous chloride (Hg2Cl2)• Table 5-3 presents a synopsis of
the three main types of primary batteries and their composition.
TABLE 5-3. MERCURY-CONTAINING BATTERIES
Cell type
HgO-Zn
Alkaline-Manaanese
batteries
Leclanche' or zinc-
carbon batteries
Cathode
1 . HgO/Mn02
2. HgO
MnO«
£.
MnO2 (10-30 wt. %
acetylene black)
Anode
Zn-Hg (amalgam)
7n-Hn
Zn-container (Prior
to 1991,
amalgamated with
HgCI2 or Hg2CI2
to minimize corro-
sion and H2
evolution)
Electrolyte
Aqueous KOH or NaOH
Aniioniie k"OU
NH4CI, ZnCI2, H20.
Prior to 1991, the paste
or solution applied to the
paper separator contained
HgCI2 or Hg2CI2
Source: References 14 and 20.
Since 1989, the use of mercury in primary batteries has decreased
from 250 Mg (275 tons) in 1989 to 78 Mg (86 tons) in 1991 (see
Table 3-2) and probably has decreased further in 1992. The
primary decrease in usage has occurred with the alkaline-
manganese batteries and the zinc-carbon batteries. The
5-11
-------
production processes underwent an obvious change during this
period to accommodate the new type of reduced mercury content
batteries. The ensuing subsections discuss each of the three
major types of batteries.
Operations at several battery manufacturing plants were
investigated in 1983 via contacts with State agencies, industry,
and site visits. Of these plants, five manufactured mercuric
oxide-zinc or mercuric oxide-cadmium batteries; seven plants
manufactured alkaline manganese batteries; and seven manufactured
Leclanche' zinc-carbon batteries but the identify of specific
plants was not disclosed.14 Table 5-4 presents the U.S.
manufacturers and production sites for mercuric oxide, alkaline
manganese, or zinc-carbon batteries in 1992.
5.2.1 Mercuric Oxide Batteries
Mercuric oxide batteries are small circular, relatively flat
batteries that are used in transistorized equipment, walkie-
talkie's, photoelectric exposure devices, hearing aids,
electronic watches, cardiac pacemakers, and other items requiring
small batteries. Of the three major types of batteries, only
this type still adds mercury (mercuric oxide) as of the end of
1992.
Process Description--
The basic flow diagram for the manufacture of mercuric oxide
batteries is shown in Figure 5-2. The mercuric oxide-zinc cells
use mercuric oxide (mixed with graphite and manganese dioxide) as
the cathode. The anode is a zinc-mercury amalgam.
In the production of the cathodes, mercuric oxide
(Stream A), manganese dioxide (Stream B), and -graphite (Stream C)
are manually metered through a hopper to the blending area.14
The resulting mixture (Stream D) is sent to a processing unit
where it is compacted into tablets by "slugging" (compression in
5-12
-------
TABLE 5-4. MERCURIC OXIDE, ALKALINE MANGANESE, OR ZINC-CARBON BATTERY
MANUFACTURERS IN 1992
Manufacturer
Alexander Manufacturing Company (AMC,
Inc.)
Duracell, USA
Eagle-Picher Industries, Inc.
Eveready Battery Company, Inc.
Mutec3
Rayovac Corp.
Production site
Mason City, IA
Cleveland, TN
LaGrange, GA
Lancaster, SC
Lexington, NC
Colorado Springs, CO
Maryville, MO
Red Oak, IA
Fremont, OH
Bennington, VT
Asheboro, NC (2 plants)
Columbus, GA (Corporate offices)
Madison, Wl
Fennimore, Wl
Portage, Wl
Source: Reference 5 and information provided by the National Electrical Manufacturers Association
(NEMA).
aMutec is a joint venture between Eastman Kodak and Panasonic.
5-13
-------
ANODE
(MERCURIC OXIDE-ZINC CELLS)
• DENOTES POTENTIAL MERCURY EMISSION SOURCE
UNCONTROLLED
EMISSIONS
Hg E >
F
U1
1
H
it-
Hgo A ».
c
GRAPHITE ~ ^
B
MnO2 ^>
AMALGAMATING
G
W
•
PROCESSING.
BLENDING, ANODE
GEL
t.
BAGHOUSE
EMISSIONS
•
MIXING AND
BLENDING
A
D
^
^
EMISSIONS
•
PROCESSING
(PELLETING,
GRANULATION.
PELLETING.
CONSOLIDATION)
i
UNCONTROLLED
EMISSIONS
•
• ^ BATTERIES (BUTTON
CELL CELLS)
MANUFACTURING
'
~! HEATING/AC AIR
L A |
1
CATHODE
(MERCURIC OXIDE-ZINC & MERCURIC OXIDE-CADMIUM CELLS)
Figure 5-2. General flow diagram for mercuric oxide battery (button cell) manufacture.14
-------
a rotary pressing device to a specified density). These tablets
are then granulated into uniformly sized particles, and then
pelletized in a rotary press. The pellets are consolidated into
small metal cans less than 1.3 cm (0.5 in.) in diameter.15
For the production of the anodes, elemental mercury
(Stream E) and zinc powder (Stream F) are metered from hoppers or
hold tanks into an enclosed blender to produce a zinc-mercury
amalgam.15 The amalgam (Stream G) is sent to a processing area
where it is blended and the anode gel formed.
The completed anodes and cathodes are then sent to the cell
manufacturing area. Separators, electrolyte, and other
components are assembled with the anode and cathode to produce
the HgO-Zn cell. Assembly may be automatic or semiautomatic.
The assembled cathode, anode, electrolyte, and cover are sealed
with a crimper. Depending on the design, other components may be
added. Those additional components may include an insulator, an
absorber, and a barrier.
An integrated mercuric oxide battery plant may also produce
HgO and recycled mercury onsite. Mercuric oxide production was
discussed in Section 4 under mercury compound production.
Secondary recovery of mercury at the battery plant was discussed
in Section 4 under secondary mercury production.
Emission Control Measures--
Baghouses are used to control particulate emissions from the
mixing/blending and processing steps in the production of
cathodes. Mercury vapor emissions from the anode processing and
cell manufacturing areas are generally discharged to the
atmosphere uncontrolled. Ventilation air in the assembly room is
recirculated through particulate filters. One plant reported an
average of 73 percent mercury vapor removal efficiency in the
cell assembly room when an .air handler system, consisting of a
5-15
-------
particulate prefliter and a charcoal filter, was operated using
75 percent recirculating air and 25 percent fresh air.15
In addition to the emission control measures, other methods
can be used to reduce potential worker exposure in the workplace.
Table 5-5 summarizes the types of methods used in the workplace
to reduce worker exposure to mercury vapor and particulate during
battery manufacturing.
Reject materials such as anodes, cathodes, chemical mixes,
and cells can be stored under water to suppress mercury
vaporization.15
Machinery for grinding, mixing, screening, pelletizing,
and/or consolidating can be enclosed with little or no need for
worker access. Two mercuric oxide button cell manufacturers in
1983 were using such enclosures and glove boxes to reduce worker
exposure. Iris ports allowed access to the enclosed equipment.
Exhaust airstreams are generally ducted to a baghouse. These
facilities also used ventilated enclosures to store completed
anodes and cathodes on the cell assembly lines; the exhaust air
takeoffs from these enclosures led to a baghouse.15
Emissions--
During the manufacture of mercuric oxide batteries, mercury
may potentially be emitted from several processes as particulate
and as vapor emissions. These release points are indicated in
Figure 5-2 by a solid circle. The processes include grinding,
mixing, sieving, pelleting, and/or consolidating.
The only reported emission factor for a mercuric oxide
production facility was for one plant in Wisconsin.19 This
facility used a combination of a baghouse and" charcoal filter to
treat the exhaust ventilation air. Annual use of mercury was
36.17 Mg (39.8 tons) and annual emissions were reported as
36.3.kg (80 Ib) of mercury as HgO particles. For this specific
5-16
-------
TABLE 5-5. METHODS FOR REDUCING WORKER EXPOSURE TO MERCURY
EMISSIONS IN BATTERY MANUFACTURING
Control methods
Process modification and substitution
Contaminant
Ventilated enclosure
Local exhaust ventilation
Temperature control
Dilution ventilation
Isolation
Mercury removal from air stream
Personal protective equipment
Paniculate
Xa
xa
xb,c
xa,b,c
xa,b,c
xa,c
xa,b,c
xa,b
Vapor
xd,e
xd,e
xd,e
xd,e
xd,e
xd,e
aParticulate emissions during loading of mixers and blenders in cathode preparation.
^Paniculate emissions from grinding, slugging, and pelletizing in cathode production.
°Paniculate emissions from drying, screening, and pelletizing in anode production.
dVapor emissions from blending, drying, and pelletizing during anode production.
eVapor emission from product components.
Source: Reference 15.
5-17
-------
facility, the mercury emission factor would be 1.0 Jcg/Mg
(2.0 Ib/ton) of mercury used.19 No mercury emissions were
reported for this facility in the 1990 TRI.5
This emission factor should be used with extreme caution for
several reasons. The data, both usage and emissions, are over
10 years old and emission controls may have changed in the
interim. Although it is not specifically stated in Reference 19,
it is also presumed that the mercury emission quantity is an
estimate by the manufacturer because no reference is made to any
emissions testing performed at the facility. Moreover, this
factor is for one year at one specific site so that extrapolation
of this factor to all mercuric oxide battery manufacturing
facilities can lead to erroneous results.
Based on another study, the emission source rates from an
integrated mercury button cell plant are summarized in
Table 5-6.14 Data reported for this facility also included the
HgO production plant and the mercury recovery plant, but these
data were deleted from this table because they are addressed in
Section 4. Major emission points were the pelleting and
consolidating operations (up to 42 g/d; 0.094 Ib/d) and cell
assembly (29 g/d; 0.063 Ib/d). Emission controls were not in
place for mercury vapor emissions from the main plant.14 This
plant reported total mercury emissions of 3.2 kg (7 Ib) in the
1990 TRI.5
Other HgO battery plants in 1983 consumed up to 25 percent
as much mercury as the integrated HgO plant and emitted 2 to
<200 g Hg/d (0.003 to <0.4 Ib/d). Baghouses and charcoal filters
were the primary measures used to control emissions.14
5.2.2 Alkaline-Manganese Batteries
The alkaline-manganese battery uses essentially the same
electrode materials as the Leclanche' system described in the
5-18
-------
TABLE 5-6. EMISSION SOURCE PARAMETERS FOR AN INTEGRATED
MERCURY BUTTON CELL MANUFACTURING FACILITY
Building/source no.
description3
Emission rateb
g/d
Ib/d
Exit temp., °K, and
control device
Main Plant
Control Room
1 . Blending,
slugging,
compacting,
granulating
2. Slugging,
granulating
3. Pelleting,
consolidating
4. Pelleting,
consolidating
4a. Pelleting,
consolidating
5. Blending,
compacting,
granulating,
pelleting,
consolidating
6.12
1.22
1.63C
42.46
6.53
1.36°
0.0135
0.0027
0.0036°
0.0936
0.0144
0.003a
297; Baghouse
297; Baghouse
295; Baghouse
297; Baghouse
297; Baghouse
297; Baghouse
Anode room
6. Amalgam,
dewatering
6a. Vacuum dryer
6b. Blending
7. Pelleting, zinc
amalgam
1.82C
0.46C
0.91C
4.08°
0.004C
0.001 c
0.002°
0.009°
297; Uncontrolled
297; Uncontrolled
297; Uncontrolled
295; Baghouse
Cell assembly area
8. Assembling calls
28.58
0.0630
295; Baghouse for
particulate. Vapor
by recirculating air
through prefilters and
charcoal filters
^Source numbers are the same code used by facility.
"Emission rates were measured by facility except where noted.
cEstimated emission rate by facility.
Source: Reference 14.
5-19
-------
next subsection; the only difference is the electrolyte. This
battery is characterized by good low temperature performance and
a long shelf life. Alkaline-manganese batteries are used in
movie cameras, electronic flash devices, tape recorders, toys,
shavers, and other devices resulting in a heavy-discharge use.
"The use of mercury in this battery system has decreased
considerably since 1989, and it is anticipated that little, if
any, mercury will be used by the end of 1993. Two of the major
alkaline-manganese battery manufacturers ceased adding mercury to
the batteries in 1992 and the other two major companies will
cease by the end of 1993.
Process description1^--
The process flow diagram for alkaline cell manufacture is
given in Figure 5-3. For the production of the anodes, zinc
oxide (Stream A), elemental mercury (Stream B), the electrolyte
solution (Stream C), and a gelling agent (Stream D) are mixed in
an enclosed blender to produce an anode gel. The gel is held for
a specified time and then fed manually into a grinder to remove
any lumps before transport, in sealed plastic cans, to the cell
assembly area.
The cathode is formed by compacting a mixture of manganese
dioxide (MnO2) (Stream E) and graphite (Stream F) into an annular
shape. During cell assembly, the preformed cathode is injected
into a steel can and a paper cylinder is inserted into the
cathode together with the electrolyte. The inner cylinder is
filled manually or automatically with the anode gel. The final
battery is produced by placing current collectors on top of the
cell, crimp-closing the can, and placing the cell in a battery
casing.
Emission Control Measures-- : -••.•'
Baghouses are generally used to control particulate
emissions, particularly from the cell assembly areas-,- but mercury
vapor emissions are uncontrolled.
5-20
-------
t
U1
I
to
Mn02
Graphite
ANODE GEL
PRODUCTION:
BLENDING IN
VACUO
GRINDING
CATHODE
PRODUCTION:
MIXING
COMPACTING
INTO ANNULAR
SHAPE
PLACING
CURRENT
COLLECTORS
ON TOP OF
CELL
PLACING
CELL IN
BATTERY
CASING
DENOTES POTENTIAL MERCURY EMISSION SOURCE
Figure 5-3. Alkaline cell manufacture.15
-------
Emissions--
During the production of alkaline-manganese batteries,
mercury may be emitted primarily from the anode gel production
area as denoted on Figure 5-3 by a solid circle. The only
reported emissions data are for an alkaline-manganese battery
production facility in Wisconsin.19 At this facility, mercury
vapor from the blender in the gel production aj^a was passed
through charcoal filters prior to discharge; no other control
measures were stated for other production areas. Annual use of
mercury was 33.0 Mg (36.4 tons) and annual air emissions from the
facility were reported to be 0.9 kg (2 Ib) of mercury. The
mercury emission factor for this facility would be 0.03 kg/Mg
(0.05 Ib/ton) of mercury used. This facility reported annual
emissions of 4.5 kg (10 Ib) in the 1990 TRI.5
This emission factor should be used with extreme caution
because of several reasons. The data, both usage and emissions,
are over 10 years old and emission controls may have changed in
the interim. Although it is not specifically stated in
reference 19, it is also presumed that the mercury emission
quantity is an estimate by the manufacturer because no reference
is made to any emissions testing performed at the facility.
Moreover, this factor applies to a given year at a specific site,
and extrapolation of this factor to other alkaline-manganese
production facilities can lead to erroneous results.
5.2.3 Leclanche' Zinc^Carbon Batteries
The Leclanche' cell or zinc-carbon battery has been a major
factor in the primary battery market since its introduction in
the 1860's. Prior to 1989, the dry cells used a cathode of
manganese dioxide, and acetylene black, and an anode of zinc.
There are two general categories for the dry cell: round and
flat, but the difference is primarily physical, not chemical.
The popularity of these dry cells is due in part to their
relatively low cost, availability in many voltages and sizes, and
5-22
-------
suitability for intermittent and light-to-medium current drainage
uses. Zinc-carbon batteries find extensive use in numerous
commercial products.20"22 Like the alkaline-manganese battery,
the use of mercury in this battery system has decreased since
1989. It is doubtful that any mercury was still in use by the
end of 1992 for the production of zinc-carbon batteries.
Process Description--
The overall process for the manufacture of zinc-carbon
batteries did not change significantly with the removal of
mercury from the process. In these batteries, the mercury was
present to retard detrimental side reactions in the cell, to
increase shelf life, and as a corrosion inhibitor; mercury was
not an integral part of the cell reaction. It was the
development of alternative methods and materials that led to the
removal of mercury from these batteries. The primary detrimental
effect in these batteries is side reactions and the leakage of
air into the battery cell; air dries out the cell medium (a paste
or moist paper 'separator) and provides the oxygen necessary for
corrosion of the battery container which results in gas
formation. Three major improvements were made in the battery
construction:
1. Improved integrity of the seals of the battery;
2. Quality of the raw materials; and
3. Development of nonmercury inhibitors.
The improved integrity of the seals in the battery containers led
to a significant reduction in air leakage into the battery and '
reduced gas formation. Requirements for higher purity raw
materials resulted in fewer detrimental side reactions that would
affect the battery integrity. Finally, the development of
effective nonmercury corrosion inhibitors made the use of mercury
unnecessary. The chemical nature of these corrosion inhibitors
is highly proprietary with each company so no information can be
provided regarding their chemical structure or type.
5-23
-------
The removal of mercury from the production of zinc-carbon
batteries negates the need for any discussion of the -emission
control measures for mercury as well as any discussion of mercury
emissions during the production process. Therefore, no further
discussion of zinc-carbon batteries is presented.
5.3 ELECTRICAL USES
Because mercury is rated as one of the best electrical
conductors among the metals, it is used in many electrical
applications including electric switches, electric lamps, thermal
sensing elements, and other electrical uses.
5.3.1 Electric Switches
The primary use of elemental mercury is for silent electric
wall switches and electric switches for thermostats. The mercury
"buttons" used in wall switches consist of mercury, metal
electrodes (contacts), and an insulator. The thermostat switches
are constructed of a short glass tube with wire contacts sealed
in one end of the tube. An outside mechanical force or gravity
activate the switch by causing the mercury to flow from one end
of the tube to the other, thus providing a conduit for electrical
flow.
The National Electrical Manufacturers Association (NEMA) was
contacted for manufacturers of electric switches that may contain
mercury in the devices. The fifteen companies identified by NEMA
were contacted to determine whether mercury was used at any of
their production facilities. Of the fifteen companies, seven
stated that no mercury was used at their production facilities.
General Electric Corporation stated that thermostats, both with
and. without mercury, were produced at their Morrison, Illinois
facility. Honeywell, Inc. produces microswitches that contain
mercury.at. their Freeport, Illinois facility. The. six companies
shown below either declined to provide any information or
5-24
-------
provided a response for only a portion of their divisions and
declined to comment on the other divisions.
Company
Eaton Corporation
Emerson Electric Co.
Johnson Controls, Inc.
Ranco, Inc.
Therm-0-Disc
United Technologies
Corporate Headquarters
Cleveland, OH
St. Louis, MO
Milwaukee, WI
Plain City, OH
Mansfield, OH
Huntington, IN
Process Description--
Mercury Buttons for Wall Switches1^--The manufacture of
mercury buttons for wall switches is shown in Figure 5-4. In this
process, a metal ring, glass preform, ceramic center, and center
contact are assembled on a semiautomatic loader (Step 1) and
fused together in a sealing furnace (Step 2)'. Each subassembly
is then transferred to a rotating multistation welding machine,
which is completely enclosed, where the subassembly is filled
with about 3 g (0.11 ounces) of mercury (Step 3). The mercury
used to fill the subassembly is stored in an external container.
During the subassembly filling step, the mercury container is
pressurized with helium; this pressurization transfers the
mercury from the large storage container to a smaller holding
tank. Mercury is released in a controlled manner from the
holding tank by using a rotating slide gate that is synchronized
to the welding machine speed. The filled subassembly is manually
placed in the can, evacuated, and welded shut to form the button
(Step 4).
After leaving the isolation room, the buttons are cleaned
(Step 5), zinc plated (Step 6), and assembled with other
components (Step 7) to form the finished wall switches.
Thermostat Switches--The production process for thermostat
.switches used for household heating/air conditioning -control, and
other applications is shown in Figure 5-5. Metal electrodes
5-25
-------
PRESSURIZED
HELIUM
Ul
i
to
i
ASSEMBLY OF
METAL RING. GLASS
PREFORM. CERAMIC
CENTER. AND
CENTER CONTACT
EVACUATION
AND WELDING
OF METAL CAN
ASSEMBLY
WITH OTHER
COMPONENTS
INTO WALL
SWITCHES
ISOLATION ROOM
DENOTES POTENTIAL MERCURY EMISSION SOURCE
Figure 5-4. Manufacture of mercury buttons for wall switches.'5
-------
U1
I
to
J
ELECTRODES
(CONTACTS)
EMPLACEMENT
INTO GLASS TUBES
2
TUBE
EVACUATION
MEF1CURY
RESEIRVOIR
Hg
3
•
•f
•
MERCURY
FILING
(AUTOMATIC
OR M/iNUAL)
•
4
WEI
(SEAL
FILLEC
,
5
1
•
.DING
ING) OF
) TUBES
6 7
FINISHED
^ ^ ATTACHMENT ^ SWITCH
TO ELECTRODE
CONTACTS
.
EXCESS GLASS
DISCHARGE
INTO WATER
ISOLATION FILL ROOM
DENOTES POTENTIAL MERCURY EMISSION SOURCE
Figure 5-5. Thermostat switch manufacture.15
-------
(contacts) are inserted into one end of a glass tube 0.89 to
1.5 cm (0.35 to 0.59 in.) in diameter (Step 1). This end of the
tube is then heated, crimped around the electrodes, and then
sealed. The apparatus is then cleaned, transferred to the
isolation fill room, and loaded onto the filling machine where
the tubes are evacuated (Step 2). At the filling machine (Step
3), the vacuum in the glass tube is released and mercury is drawn
into the tube. The open end of the mercury-filled tube is
heated, constricted, and sealed (Step 4). Filling of switch
tubes produced in low volume is performed manually using the same
sequence of steps. Excess glass at the seal is discarded into a
bucket of water (Step 5). The filled tube leaves the isolation
room and falls into a transport container (Step 6). Attachment
of wire leads to the electrode contacts completes the switch
assembly (Step 7).
Emission Control Measures15--
Table 5-7 shows typical emission control methods used in the
mercury switch industry to reduce worker exposure to mercury
vapor.
The use of isolation rooms and automated systems for fill
operations in the manufacture of mercury buttons has reduced
considerably the manual handling of elemental mercury. For
example, a mercury refiner supplies 363 kg (800 Ib) of mercury in
stainless steel storage containers that are individually mounted
in steel frames to permit lifting and transport by forklift. The
alternative procedure is to manually transfer the mercury from
76-Ib iron flasks to the holding tank.
The use of effective gaskets and seals allows containment of
mercury in the process streams. Reject and broken switches are
discarded under water to suppress mercury vaporization.
Exhaust ventilation, which is custom designed to fit
specific equipment, is often used to reduce worker exposure to
. 5-28
-------
TABLE 5-7. MEASURES TO REDUCE WORKPLACE EXPOSURE TO MERCURY
VAPOR EMISSIONS IN THE ELECTRIC SWITCH INDUSTRY
Control method
Process modification and
substitution
Containment
Ventilated enclosure
Local exhaust ventilation
Temperature control
Dilution ventilation
. Isolation
Sources
Hg purification
and transfer
X
X
X
X
X
X
Hg filling
X
X
X
Product testing
X
X
X
X
Spills,
breakage,
rejects
X
-
X
X
X
Source: Reference 15.
mercury vapor, mercury particulate, or both. For example, a
specially designed circular slot hood may be used to cover the
filling and welding machine. Plastic strip curtains may be
suspended from the hood to help prevent airflow from the hood
into the work room.
Temperature control is widely practiced as one of the most
effective measures to reduce mercury emissions. Reducing the
fill room temperature to between 18° and 20°C (64° and 68°F) can
be effective in lowering mercury emissions. Some industry
operations shut down and require personnel evacuation from the
room when temperatures rise above 21°C (70°) .
Dilution ventilation of fill room air, without apparent
control, has been practiced at mercury switch plants. The
negative pressure in the fill room prevents escape of mercury
vapor into adjacent assembly areas.
5-29
-------
Examples of technology for removing mercury from exhaust
streams were not found. However, controls used at other
manufacturers of electrical and electronic items may be effective
at mercury switch plants. These controls are discussed in
subsequent subsections.
Emissions^-
During the manufacture of electric switches (wall and
thermostat), mercury may potentially be emitted during welding or
filling, as a result of spills or breakage, during product
testing, and as a result of material transfer. The mercury
emission sources are indicated in Figures 5-4 and 5-5 by a solid
circle.
Table 5-8 lists the five manufacturers of electric switches
that reported mercury air emissions in the 1990 Toxics Release
Inventory.5 Total reported emissions from these manufacturers
was 14 pounds.
No mercury emission data have been published for other
manufacturers of electrical switches. In the production of
either mercury buttons for wall switches or thermostat switches,
the principal sources of mercury emissions occur during filling
processes that are conducted in isolated rooms. The isolation
rooms are vented to maintain the room at a slight negative
pressure and prevent mercury contamination of adjacent work
areas. However, no emission data or results of tests are
available to develop an estimate of mercury emissions from these
two processes.
5.3.2 Thermal Sensing Elements15
In certain temperature-sensing instruments, a bulb and
capillary temperature-sensing device is an integral part of the
instrument. These devices use the expansion force of mercury as
5-30
-------
TABLE 5-8. MANUFACTURERS OF ELECTRIC SWITCHES AND ELECTRONIC COMPONENTS
REPORTING IN THE 1990 TOXICS RELEASE INVENTORY
Facility
Babcock Display
Products
Durakool, Inc.
Emerson Puerto Rico
Inc.
Hermaseal Co.
Micro Switch
Honeywell Div.
Location
Anaheim, CA
1010 N. Main Street
Elkhart, IN
Dorado, PR
1101 Lafayette
Elkhart, IN
Freeport, IL
Comments
Gas discharge display;
Hg used as a formulation
component and possibly
recycled
Repackaging only
Switch gear and
switchboard apparatus
Hg used for "ancillary or
other use"
Repackaging only
Hg used as an article
component
Total annual air
emissions, Ib
0
5
0
5
4
Source: Reference 5.
5-31
-------
it is heated to activate the external controls and indicators of
the instrument.
Process Description--
A thermal sensing instrument consists of a temperature-
sensing bulb, a capillary tube, a mercury reservoir, and a spring
loaded piston. The bulb is made by cutting metal tubing to the
correct size, welding a plug to one end of the tube, and
attaching a coupling piece to the other end. The capillary tube
is cut to a specified length and welded to the coupling at the
open end of the bulb. The other end of the capillary is welded
to a "head" that houses the mechanical section of the sensor.
The bulb and capillary assembly are filled with mercury by a
multistation mercury filling machine that is housed in a
ventilated enclosure. After filling, the sensor is transferred
to a final assembly station where a return spring and plunger are
set into a temporary housing on the head of the sensor. To
complete the temperature instrument, the sensor is then attached
to a controller and/or indicating device.
Emission Control Measures--
No information was found on specific emission control
devices or measures to control mercury emissions during the
filling process. Although the filling machine is typically in a
ventilated enclosure, no information is available concerning any
subsequent treatment of the exhaust gas prior to discharge to the
atmosphere.
Emissions--
No emission factors for mercury emissions from thermal
sensing element manufacturing were found in the literature, and
no .emission test data were available to calculate" emission . '"
factors.
5-32
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5.3.3 Tungsten Bar Sintering1^
Process Description--
Tungsten is used as a raw material in the manufacture of
incandescent lamp filaments. The manufacturing process starts
with tungsten powder pressed into long, thin bars of a specified
weight. These bars are pretreated and -then sintered using a
high-amperage electrical current. During the tungsten bar
sintering process, mercury is used as a continuous electrical
contact. The mercury contact is contained in pools (mercury
cups) located inside the sintering unit.
After the sintering process is completed, the bars are
cooled to ambient temperature to determine the density of the
tungsten bar. Metallic mercury is normally used in these
measurements because of its high specific gravity. To calculate
the density of the tungsten bar, the bars are dipped into a pool
of mercury, and the weight of the displaced mercury is
determined. When the bar is removed from the mercury pool, the
mercury is brushed off into a tray of water that is placed in
front of the pool.
Emission Control Measures--
No specific information on emission control measures for
sintering tungsten bars was found in the literature.
Emissions--
Mercury is used only during the actual sintering and the
final density measurements. For this reason, it is assumed that
these two operations account for all the mercury emitted from the
process. No specific data for mercury.emissions from the
tungsten sintering process were found in the literature, and no
.emission test data were available to calculate mercury emission
factors.
5-33
-------
5.3.4 Copper Foil Production^
High purity copper foil, used as a laminate in printed
circuit boards, is produced by an electrodeposition process using
mercury as the electrical contacts.
Process Description--
The initial step in the foil production process is the
dissolution of scrap copper in sulfuric acid to form copper
sulfate. The solution is then fed to the plating operation where
the copper ions are electrodeposited on rotating drums as copper
metal. Each plating drum is composed of a concrete cell
containing the copper sulfate solution, an anode (lead), a
rotating titanium drum (cathode), and a winding roll. During the
electrodeposition process, a current passes between the lead
anode and the rotating drum cathode. As the drum rotates, the
copper metal is electrodeposited on the drum surface in the form
of a continuous thin foil sheet.
Elemental mercury is used as the continuous contact between
the rotating shaft of the rotating drum and the electric
connections. The liquid mercury is contained in a well located
at one end of the rotating drum shaft.
Emission Control Measures--
Manufacturing processes that require mercury as an
electrical contact generally use ventilated enclosures for
controlling vapor emissions from mercury pools. In copper foil
production, the mercury wells are located in ventilated
enclosures, and exhaust gases are directed to a mercury vapor
filter. Another method of controlling emissions from mercury
wells is to reduce the temperature of mercury in the well.
Generally, mercury wells operate at 82°C (180°"F) ; at this
temperature, mercury has a vapor pressure of 0.10 mmHg. A
temperature reduction to 21°C (70°F) decreases the mercury vapor
pressure to 0.0013 mmHg.
5-34
-------
Emissions--
Mercury is emitted from the drum room and treatment room of
the copper plating process. No information was available on
mercury release rates to the atmosphere through ventilation
systems. No specific data for mercury emissions from the
production of copper foil were found in the literature, and no
emission test data were available for calculating emission
factors.
5-.3.5 Fluorescent Lamp Manufacture15
Information obtained from NEMA indicates that there were
four fluorescent lamp manufacturers in the U.S. in.1992. The
names and production facility locations are presented in
Table 5-9. •
TABLE 5-9. FLUORESCENT LAMP MANUFACTURING
Company
Duro-Test Corp.
General Electric
Osram/Sylvania, Inc.
Philips Lighting Co.
Plant Location
North Bergen, NJ .
Bucyrus, OH
Circleville. OH
Danvers, MA
Manchester, NH
Versailles, KY
Fairmont, WV
Salina, KS
Bath, NY
Comments
Division Headquarters; Declined to
identify production facility locations
Standard fluorescent lamps
Standard fluorescent lamps
Standard fluorescent lamps
HID (high intensity discharge) lamps
HID lamps and standard fluorescent lamps
Ultraviolet and germicidal lamps
Standard fluorescent lamps
Mercury vapor lamps and HID lamps
Process Description--
Fluorescent lamp production begins with the preparation of
the lamp tube. Precut glass tubes are washed to remove -
impurities, dried with hot air, and coated with a liquid phosphor
emulsion that deposits a film on. the inside of the lamp tube.
Mount assemblies, consisting of a short length of glass exhaust
tube, lead wires, and a cathode wire, are fused to each end of
5-35
-------
the glass lamp tube. The glass lamp tube, with attached mount
assemblies, is then transferred to the exhaust machine.
On the exhaust machine, the entire glass tube system is
exhausted and a small amount (15 - 250 mg/3.3 x 10"5-5.5 x 10"4
Ib) of mercury is added, which adheres to the emulsion coating on
the interior of the glass lamp tube. Following the addition of*
mercury, a vacuum is drawn through the exhaust tubes to remove
excess mercury and evacuate the glass lamp tube system. The
glass tube system is then filled with inert gas and sealed.
After the lamp tubes are sealed, metal bases are attached to the
ends of the lamp tube and are cemented in place by heating.
Emission Control Measures--
No emission control measures were identified for exhaust or
ventilation gases. The only methods identified were those used
to reduce worker exposure. Mercury air concentrations due to
handling are usually reduced by containment, local exhaust
ventilation, temperature control, isolation, and/or mercury
removal from the air stream. Mercury air levels during the lamp
production steps are reduced by process modifications,
containment, ventilated enclosures, local exhaust ventilation,
and temperature control.
In 1991, 29 Mg (32 tons) of mercury were used to manufacture
electric lamps, including fluorescent, mercury vapor, metal
halide, and high-pressure sodium lamps. These lamps are used in
street lights, high-ceiling rooms, film projectors, photography,
dental exams, photochemistry, heat lamps, and water purification.
In 1980, it was estimated that the amounts of mercury used for
indoor and outdoor applications were equally divided.^
Emissions--
Mercury emissions during fluorescent lamp manufacturing
occur during mercury handling and lamp production. -Mercury
handling procedures result in vapor emission from mercury
5-36
-------
purification, transfer, and parts repair. Lamp production
results in mercury emissions from the injection operation and
from broken lamps, spills, and waste material.
A 1984 emission rate of 10.2 g/d (0.02 Ib/d) was found in
NATICH (National Air Toxics Information Clearinghouse) for a GTE
lamp manufacturing facility in Kentucky. 4 However, no
information was available on the quantity of mercury used at the
facility, the number of units produced, or other data that would
permit a comparison of this emission rate with other facilities.
In addition, no data were presented to allow calculation of an
annual quantity. Only one lamp manufacturing facility (General
Electric Company Bucyrus Lamp Plant) reported mercury emissions
in the 1990 TRI; their annual emissions were 0.44 Mg/yr
(0.48 tons/yr).5
About 50 percent of the mercury used to manufacture electric
lamps is for outdoor applications. About one-third of this
amount is lost to the atmosphere annually after the lamp is
broken and about one-fifth of the amount used in indoor lamps is
lost upon disposal. 3
5.4 INSTRUMENT MANUFACTURING AND USE (THERMOMETERS)
Mercury is used in many medical and industrial instruments
for measurement and control functions including thermometers;
manometers, barometers, and other pressure-sensing devices;
gauges; valves; seals; and navigational devices. Because mercury
has a uniform volume expansion over its entire liquid range and a
high surface tension, it is extremely useful in the manufacture
of a wide range of instruments. Process descriptions, emission
control measures, and emissions are limited to a very few
5-37
-------
instruments. One of those instruments is the thermometer and the
ensuing discussion will focus on that instrument.
5.4.1 Process Description14'15
The manufacture of temperature measurement instruments
varies according to the type of bulb or probe. In addition, the
mercury filling procedure varies among different instrument
manufacturers. The production of glass thermometers begins with
cutting glass tubes into required lengths. Next, the bulb used
to contain mercury is attached to the tube; either glass or metal
bulbs may be used.
The tubes are filled with mercury in an isolated room. A
typical mercury filling process is conducted inside a bell jar.
Each batch of tubes is set with open ends down into a pan and the
pan set under the bell jar, which is lowered and sealed. The
tubes are heated to approximately 200°C (390°F) and a vacuum is
drawn inside the bell jar. Mercury is allowed to flow into the
pan from either an enclosed mercury addition system or a manually
filled reservoir. When the vacuum in the jar is released, the
resultant air pressure forces the mercury into the bulbs and
capillaries. After filling, the pan of tubes is manually removed
from the bell jar. Excess mercury in the bottom of the pan is
refiltered and used again in the process.
Excess mercury in the tube stems is forced out the open ends
by heating the bulb ends of the tubes in a hot water or oil bath.
The mercury column is shortened to a specific height by flame-
heating the open ends (burning-off process). The tubes are cut
to a finished length just above the mercury column, and the ends
of the tubes are sealed. All of these operations are performed
manually at various work stations. A temperature scale is etched
onto the tube, completing the assembly.
5-38
-------
5.4.2 Emission Control Measures
Several emissions control measures have been identified for
production processes that require, in part, the filling of an
apparatus with metallic mercury. In the previous discussion of
the electric switch industry, Table 5-8 delineated several
control methods that are used by that industry. To a large
extent, these controls or combination of controls are generally
applicable to the production of thermometers. Within the
industry, vapor emission from mercury purification and transfer
is typically controlled using containment-procedures, local
exhaust ventilation, temperature reduction to reduce the vapor
pressure, dilution ventilation, or isolation of the operation
from other work areas. The tube bore size can be modified to
reduce the use of mercury. Other measures that may be applied
are use of local exhaust ventilation, dilution ventilation, and
temperature control.
The major source of mercury emissions in the production of
thermometers may be in the mercury filling step. In this step,-
virtually all of the control measures identified in Table 5-8
would be applicable, to some degree. One of the latter steps in
the production involves heating the mercury in a high temperature
bath and the subsequent heating of the open ends with a flame
(burning-off process). This stage of the production would be
particularly amenable to a ventilated isolation room, using local
exhaust ventilation in addition to dilution ventilation, to
create a slight negative pressure in the room. This procedure
would prevent escape of mercury vapor into adjacent assemble or
N
work areas.
5.4.3 Emissions
Mercury emissions can occur from several sources during the
production of thermometers. From the available information, many
of the procedures used in the production are manual and, as a
5-39
-------
result, it is more difficult to control the mercury emissions.
The most prevalent sources of emissions result from three steps
or stages in the process: (1) mercury purification and transfer,
(2) the mercury filling process, and (3) the heating out/burning
off steps. Vapor emission due to spills of mercury, broken
thermometers, and other accidents can add to the level of
emissions.
No specific data for mercury emissions from the manufacturer
of thermometers were found in the literature, and no emission
test data were available to permit the calculation of mercury
emissions.
5-40
-------
SECTION 6
EMISSIONS FROM COMBUSTION SOURCES
Mercury is often found as a trace contaminant in fossil
fuels or waste materials. When these materials are fed to
combustion processes, the combination of the elevated temperature
of the process and the volatility of mercury and mercury
compounds results in mercury being emitted in the combustion gas
exhaust stream. This section addresses mercury and mercury
compound emissions from seven stationary source combustion
processes:
- Coal combustion
- Oil combustion
- Natural gas combustion
- Wood combustion
- Municipal waste combustion
- Sewage sludge incineration
- Medical waste incineration
These seven processes fall into two general categories. The
first four involve fuel combustion for energy, steam, and heat
generation, while the last three are primarily waste disposal
processes, although some energy may be recovered from these
processes. The paragraphs below provide a general introduction
to the two combustion categories. As part of this introduction,
a summary of nationwide fuel usage is presented in detail. This
information was used in Section 3 to develop nationwide emissions
of mercury for different sectors and fuels. It is included in
the introduction rather than in individual sections because
(1) the individual sections are organized by fuel type rather
than by use sector and (2) fossil fuel use patterns differ
6-1
-------
geographically and by industry sector. The introduction also
briefly describes the waste combustion category. Specific
discussions for the seven source categories follow these
introductory paragraphs.
In 1990, the total annual nationwide energy consumption in
the United States was 85.533 X 1012 megajoules (MJ)
(81.151 X 1015 British thermal units [Btu]).25 Of this total,
about 52.011 X 1012 MJ (49.347 X 1015 Btu) or 61 percent involved
consumption of coal, petroleum products, and natural gas in
nontransportation combustion processes. (No data were available
on energy consumption for wood combustion from the U.S.
Department of Energy.) Table 6-1 summarizes the 1990 U.S.
distribution of fossil fuel combustion as a function of fuel type
in the utility, industrial, commercial, and residential sectors.
The paragraphs below provide brief summaries of fuel use
patterns; additional details on fuel consumption by sector for
each State can be found in Reference 25.
As shown in Table 6-1, the utility sector is the largest
fossil fuel energy consumer at the rate of 21.290 X 1012 MJ
(20.199 X 1015 Btu) per year. About 80 percent of this energy
was generated from coal combustion, with bituminous and lignite
coal contributing substantially greater quantities than
anthracite coal. In fact, Pennsylvania is the only State in
which anthracite coal is used for electric power generation.
Although most States rely primarily on coal for power generation,
the distribution among fossil fuels varies from State to State,
and several States rely heavily on natural gas and fuel oil for
power generation. In California, natural gas provides about
90 percent of the fossil-fuel based electricity production, and
no coal is used. In Hawaii, fuel oil is used exclusively, while
in Oklahoma and Texas, a mixture of coal and natural gas are
used. In Florida, Louisiana, Massachusetts, and New York, coal,
fuel oil, and natural gas each represent a substantial fraction
of the power generation. The States of Idaho, Maine, Rhode
6-2
-------
TABLE 6-1. DISTRIBUTION OF FOSSIL FUEL CONSUMPTION
IN THE UNITED STATES
Fuel
Bituminous/
lignite coal
Anthracite coal
Distillate oil
Residual oil
Other petroleum fuels
Natural gas
Total
Annual energy consumption
1012 MJ(1015Btu)
Utilities
16.939
(16.071)
0.018
(0.017)
1.201
(1.139)
0.091
(0.086)
0.026
(0.025)
3.015
(2.861)
21.290
(20.199)
Industrial
2.892
(2.744)
0.010
(0.010)
1.245
(1.181)
0.436
(0.414)
7.083
(6.720)
8.925
(8.468)
20.591
(19.537)
Commercial
0.085
(0.081)
0.013
(0.012)
0.513
(0.487)
0.255
(0.242)
0.197
(0.187)
2.907
(2.758)
3.970
(3.767)
Residential
0.045
(0.043)
0.019
(0.018)
0.882
(0.837)
-
0.452
(0.429)
4.762
(4.518)
6.160
(5.845)
Total
19.961
(18.939)
0.060
(0.057)
3.841
(3.644)
0.782
(0.742)
7.758
(7.361)
19.609
(18.605)
52.011
. (49.347)
en
i
Source: Reference 25.
-------
Island, and Vermont had no coal consumption. Idaho relies
exclusively on hydroelectric power, while the New England States
use a mixture of fuel oil, natural gas, nuclear, and
hydroelectric power.
At 20.591 X 1012 MJ (19.537 X 1015 Btu) per year, the
industrial sector is the second largest consumer of fossil fuels.
This sector uses a mixture of natural gas (43 percent), fuel oil
(8 percent), other petroleum fuels (34 percent), and coal
(14 percent). The other petroleum fuels that are used include
primarily liquified petroleum gas, asphalt and road oil, and
other nonclassified fuels. Again, the distribution among the
three fuel types varies substantially from State to State, with
each of the three contributing significant fractions in most
States. Notable exceptions are Hawaii, which relies almost
exclusively on petroleum fuels; Alaska, which relies primarily on
natural gas; and the northeastern States of Connecticut, New
Hampshire, Rhode Island, and Vermont, which use almost no coal.
As shown in Table 6-1, substantially smaller quantities of
fossil fuel are used in the commercial and residential sectors
than are used in the utility and industrial sectors. The fuels
used are primarily natural gas, fuel oil, and liquified petroleum
gas (the "other petroleum fuels" in the residential category).
Almost all States use a mixture of the fuels, but the
distributions vary substantially, with some States like
California and Louisiana using primarily natural gas and others
like New Hampshire and Vermont using a much greater fraction of
fuel oil. One unique case is Pennsylvania where anthracite coal
is used in both the residential and commercial sectors.
In the individual sections below, additional information
will be- presented on the mercury content of the different fuels
and on the relationship between fuel type and emissions.
However, for any geographic area, the contribution of energy
generation sources to mercury emissions will be a function of the
6-4
-------
distribution of fuels used in the different sectors within the
area.
The sources within the second combustion category are
engaged primarily in waste disposal. Mercury emissions from
these processes are related to the mercury levels in the waste.
The different waste types are generally characterized with
distinct source categories. Furthermore, these waste disposal
practices are not strongly related. Consequently, each of these
categories will be characterized individually within the sections
below rather than in a general discussion here. The eight
sections below have a consistent organization. First, the
characteristics of the fuel or waste are described and, in the
case of the waste combustion processes, the general source
category is also described. Second, process descriptions are
presented and emission points are identified. Third, available
emission control measures are identified and described. Finally,
emission factors are presented. A discussion of the sampling and
analytical methods'used to determine the mercury emission levels
from combustion sources is presented in Section 9.
6.1 COAL COMBUSTION
As presented in Table 6-1, most coal combustion in the
United States occurs in the utility and industrial sectors, with
about 85 percent being bituminous and lignite combustion within
the utility sector and about 14 percent being bituminous and
lignite combustion in the industrial sector. Consequently, the
focus of the discussion below will be on bituminous and lignite
coal combustion in utility and industrial boilers. However,
limited information on anthracite coal combustion will also be
presented.
6-5
-------
6.1.1 Coal Characteristics
The coal characteristics of greatest interest in evaluating
mercury emissions from coal combustion are coal heating values
and coal mercury content. Mercury emissions are a direct
function of the mercury content, while heating values are used to
convert emission factors between mass input-based and heat
input-based activity levels. This section briefly summarizes the
information about coal heating levels and mercury content
contained in References 26 through 28. More complete summaries
can be found in Reference 26, and detailed analyses of coal
mercury content as a function of coal type and geographic region
can be found in References 27 and 28.
Coal is a complex combination of organic matter and
inorganic ash formed in geologic formations from successive
layers of fallen vegetation and other organic matter. Coal types
are broadly classified as anthracite, bituminous, subbituminous,
or lignite,' and classification is made by heating values and
amounts of fixed carbon, volatile matter, ash, sulfur, and
moisture. ^ Formulas for differentiating coals based on these
properties are given in Reference 30. These four coal types are
further subdivided into 13 component groups. Table 6-2
summarizes information about the heating values for these
component groups. °
The heating value of coal varies between coal regions,
between mines within a region, between seams within a mine, and
within a seam. The variability is minimal compared to that found
with trace metal levels described below, but it may be important
when fuel heat content is used as the activity level measure for
source emission calculations. Data presented in Table 6-3
illustrate the regional variability of coal heat content. Heat
content among coals from several different mines within a region
appears to exhibit greater variability than either variability
within a mine or within a seam. For the sample points presented
6-6
-------
TABLE 6-2. COAL HEATING VALUES
Coal class
Anthracite
Bituminous
Subbituminous
Lignite
Component
group
A1
A2
A3
B1
B2
B3
B4
B5
SI
S2
S3
L1
L2
Definition
Meta-anthracite
Anthracite
Semianthractte
Low volatile
bituminous
Medium volatile
bituminous
High volatile
A bituminous
High volatile
B bituminous
High volatile
C bituminous
Subbituminous A .
Subbituminous B
Subbituminous C
Lignite A
Lignite B
Source3
PA.RI
CO.PA.NM
AR,PA,VA
AR.MD.OK.PA,
WV
AL.PA.VA
AL.CO.KS.KY,
MO.NM.PA,
TN.TX.UT.VA,
WV
IL,KY,MO,OH,
UT,WY
IL,IN,IA,MI
MT.WA
WY
CO.WY
ND.TX
NA
Heating value, kj/kg (Btu/lb)
Range3
21,580-29,530
(9,310-12,740)
27,700-31,800
(11,950-13,720)
27,460-31,750
(11,850-13,700)
30,640-34,140
(13,220-14,730)
31,360-33,170
(13,530-14,310)
28,340-35,710
(12,230-14,510)
26,190-30-480
(11,300-13,150)
24,450-27,490
(10,550-11,860)
23,940-25,820
(10,330-11,140)
21,650-22,270
(9,340-9,610)
19,280-19,890
(8,320-8,580)
16,130-17,030
(6,960-7,350)
NA
Mean3
25,560
(11,030)
30,270
(13,000)
29,800
(12,860)
32,400
(13,980)
32,170
(13,880)
31,170
(13,450)
28,480
(12,290)
26,030
(11,230)
24,890
(10,740)
21,970
(9,480)
19,580
(8,450)
16,660
(7,190)
NA
Source: Reference 26.
aNA = not available.
6-7
-------
TABLE 6-3. EXAMPLES OF COAL HEAT CONTENT VARIABILITY
Variability
Intermine
variability
Intramine
variability
Intraseam
variability
Coal source
Eastern U.S.
Central U.S.
Western U.S.
Eastern U.S.
Central U.S.
Western U.S.
Eastern U.S.
Central U.S.
Western U.S.
Coal heat content, Btu/lb
Mean
12,320
10,772
11,227
12,950
10,008
12,000
12,480
10,975
10,351 .
12,230
10,709
11,540
Range3
10,750- 13,891
9.147 - 12,397
9,317 - 13,134
NA
9,182 - 10,834
11,335 - 12,665
NA
9,667 - 12,284
9,791 - 10,911
NA
10,304- 11,113
NA
Percent
variation about
the mean
12.7
1C
o
17
4.8b
8.0
5.5
5.7C
12.0
5.4
3.0d
3.7
2.5e
Source: Reference 26.
aNA = not available.
bBased on a standard deviation of 624.
GBased on a standard deviation of 708.
dBased on a standard deviation of 371.
eBased on a standard deviation of 291.
6-8
-------
in Table 6-3, intermine variability averaged 15 percent,
intramine variability 7 percent, and intraseam variability
3 percent. Because few combustion sources burn coal from just
one seam or one mine, coal heat content variability may
significantly affect emission estimates that are being calculated
using emission factors, coal use data, and coal heat content
<3ata, even if the source gets all its coal from the same area of
the country.26
To an even greater extent than the heating value, the
mercury content of coal varies substantially among coal types, at
different locations in the same mine, and across geographic
regions. The most comprehensive source of information on coal
composition is the United States Geological Survey (USGS)
National Coal Resources Data System (NCRDS). Geochemical and
trace element data are stored within the USCHEM file of NCRDS.
As of October 1982, the file contained information on 7,533 coal
samples representing all U.S. coal provinces. Trace element
analysis for about 4,400 coal samples were included in the data
base. This computerized data system was not accessed during the
current study due to time and budgetary constraints and
information from USGS that indicated that few data had been added
to the system since 1972; however, a summary of the data
presented in Reference 26 was reviewed. The most extensive
source of published trace element data was produced by Swanson
et al. of the USGS.28 This report contains data for 799 coal
samples taken from 150 producing mines and includes the most
important U.S. coal seams. Data from the Swanson study was the
initial input into the USCHEM file of NCRDS. The information
presented here summarizes Brooks' review of the results published
by White and Swanson.26"28 Note that those results are
consistent with unpublished analyses conducted by USGS on the
data contained in NCRDS as of 1989.31 More information on the
sampling and analysis of mercury in coal is presented in
Section 9.
6-9
-------
Table 6-4 presents information on the mean concentration of
mercury in coal and on the distributions of mercury concen-
trations by coal type. Bituminous and anthracite coals have the
highest mean mercury concentrations, 0.21 parts per million by
weight (ppmwt) and 0.23 ppmwt, respectively. The standard
deviation of each mean either approaches or exceeds the mean,
indicating strong variation in the data. Subbituminous coals
have the greatest reported range of mercury concentrations
(0.01 to 8.0 ppm).26 Based on conversations with USGS personnel,
the means reported in Table 6-4 are regarded as typical values
for in-ground mercury concentration in coals in the United
States.
TABLE 6-4. MERCURY CONCENTRATION IN COAL BY COAL TYPE
Coal type
Bituminous
Subbituminous
Anthracite
Lignite
No. of samples
3.527
640
52
183
Mercury concentration, ppmwt
Range
<0.01 to 3.3
0.01 to 8.0
0.1 6 to 0.30
0.30 to 1 .0
Arithmetic mean
0.21
0.10
0.23
0.15
Standard
deviation
0.42
0.11
0.27
0.14
Source: Reference 26.
The concentration of mercury in coal also varies by
geographic region from which the coal is mined. Based on the
"best typical" values for each region, which are footnoted in
Table 6-5, coals from the Appalachian and Gulf Provinces have the
highest mean mercury concentration, 0.24 ppmwt for both regions.
Also, based on the best available data, the lowest mean
concentration is found in coals from the Alaska region
(0.08 ppmwt). However, note that another study showed
substantially higher levels (4.4 ppmwt). That study also showed
that the greatest range of concentration is found in coals from
6-10
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TABLE 6-5. MERCURY CONCENTRATION IN COAL BY REGION
Region
Appalachian
Interior
Illinois Basin0
Gulf Province
Northern Plains
Rocky Mountains
Alaska
No. of
samples
2,749
331
592
155
82
38
34
371
490
184
124
107
18
Mercury concentration, ppmwt
Range
<0.01-3.3
0.01-0.83
0.01-1.5
0.03-1.6
0.16-1.91
0.03-1 .0
0.01-3.8
0.01-1.48
0.01-8.0
0.02-63
Arithmetic mean
0.24a
0.24b
0.1 4a
0.14b
0.15
0.21
0.24a
0.18b
0.11a
0.11
0.09a
0.06b
0.11
0.08a
4.4b
Standard deviation
0.47
0.14
0.22
0.19
0.10
0.12
0.07
Source: Reference 26.
aValues from the White, et al. study are based on the most comprehensive data set currently available (the
NCRDS) and may be used as typical values for mercury in coal from these regions.
bValues from the Swanson, et al. study are included in the NCRDS. Arithmetic means from the entire NCROS
are more representative than means from this study, since the NCROS contains many more coal samples.
The Swanson, et al. data are included to give an idea of the range of values for mercury content in individual
coal samples from each region.
cEastem section of Interior Province.
6-11
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the Alaska region with a reported range of 0.02 to 63 ppmwt.26
The means reported in Table 6-5 may be regarded as typical
in-ground concentrations of mercury in coals from each geographic
region.
6.1.2 Process Description26'29'32
. As shown in Table 6-1, almost all coal combustion occurs in
utility and industrial boilers. Almost all of the coal burned is
bituminous and subbituminous (95 percent) and lignite
(4 percent).26 However, the processes used for the different
coals are comparable. The paragraphs below first describe the
boilers used for bituminous coal combustion. Then, lignite and
anthracite combustion are described briefly. References 29
and 32 offer additional details on these processes.
The two major coal combustion techniques used to fire
bituminous and subbituminous coals are suspension firing and
grate firing. Suspension firing is the primary combustion
mechanism in pulverized coal and cyclone systems. Grate firing
is the primary mechanism in underfeed and overfeed stokers. Both
mechanisms are employed in spreader stokers.
Pulverized coal furnaces are used primarily in utility and
large industrial boilers. In these systems, the coal is
pulverized in a mill to the consistency of talcum power (i.e., at
least 70 percent of the particles will pass through a 200-mesh
sieve). The pulverized coal is generally entrained in primary
air and suspension-fired through the burners to the combustion
chamber. Pulverized coal furnaces are classified as either dry
or wet bottom, depending on the ash removal technique. Dry
bottom furnaces fire coals with, high ash fusion-temperatures, and
dry ash removal techniques are used. In wet bottom (slag tap)
furnaces, coals with low ash fusion temperatures are used, and
molten ash is drained from the bottom of the furnace.
6-12
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Cyclone furnaces burn low ash fusion temperature coal
crushed to a 4-mesh size. The coal is fed tangentially, with
primary air, to a horizontal cylindrical combustion chamber.
Small coal particles are burned in suspension, while the larger
particles are forced against the outer wall. Because of the high
temperatures developed in the relatively small furnace volume,
and because of the low fusion temperature of the coal ash, much
of the ash forms a liquid slag that is drained from the bottom of
the furnace through a slag tap opening. Cyclone furnaces are
used mostly in utility and large industrial applications.
In spreader stokers, a flipping mechanism throws the coal
into the furnace and onto a moving grate. Combustion occurs
partially in suspension and partially on the grate. Because the
entrained particles in the furnace exhaust have substantial
carbon, fly ash reinjection from mechanical collectors is
commonly used to improve boiler efficiency. Ash residue in the
fuel bed is deposited in a receiving pit at the end of the grate.
In overfeed stokers, coal is fed onto a traveling or
vibrating grate and burns on the fuel bed as it progresses
through the furnace. Ash particles fall into an ash pit at the
rear of the stoker. "Overfeed" applies because the coal is fed
onto the moving grate under an adjustable gate. Conversely, in
"underfeed" stokers, coal is fed upward into the firing zone by
mechanical rams of screw conveyers. The coal moves in. a channel,
known as a retort, from which it is forced upward, spilling over
the top of each side to feed the fuel bed. Combustion is
completed by the time the bed reaches the side dump grates from
•which the ash is discharged to shallow pits.
The next most common coal used in the U.S. is lignite.
..Lignite is a relatively young coal with properties intermediate
to those of bituminous coal and peat. Because lignite has a high
moisture content (35 to 40 weight percent) and a low wet basis
heating value (16,660 kJ/kg [7,190 Btu/lb}), it generally is used
6-13
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as a fuel only in areas in which it is mined. Lignite is used
mainly for steam/electric production in power plants and
typically is fired in larger pulverized coal-fired or
cyclone-fired boilers.
Anthracite coal is a high-rank coal with more fixed carbon
and less volatile matter than either bituminous coal or lignite.
Because of its low volatile matter content and slight clinkering,
anthracite is most commonly fired in medium-sized traveling grate
stokers and small hand-fired units. Some anthracite
(occasionally with petroleum coke) is used in pulverized
coal-fired boilers, and it may be blended with bituminous coal.
Because of its low sulfur content (typically less than 0.8 weight
percent) and minimal smoking tendencies, anthracite is considered
a desirable fuel in areas where it is readily available. In the
United States, anthracite is mined primarily in northeastern
Pennsylvania and consumed mostly in Pennsylvania and surrounding
States. The largest use of anthracite is for space heating.
Lesser amounts are employed for steam/electric production,
typically in underfeed stokers and pulverized coal dry-bottom
boilers.
Although small quantities of mercury may be emitted as
fugitive particulate matter from coal storage and handling
operations, the primary source of mercury and mercury compound
emissions from coal combustion is the combustion stack. Because
the combustion zone in boilers operates at temperatures in excess
of 1100°C (2000°F), the mercury in the coal is vaporized and
exits the combustion zone as a gas. As the combustion gases
pass through the boiler and the air pollution control system,
they cool, and some of the mercury and mercury compounds may
condense on the surface of fine particles. The relative
fractions of vapor- and particle-phase mercury in the exhaust
stack depend primarily on the temperature of the air pollution
control system, and the amount of residual carbon in the coal fly
ash (some of the vaporous mercury and mercury compounds will
6-14
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adsorb onto carbon at temperatures present in some air pollution
control devices). To date, little information has been obtained
on these distributions.
6.1.3 Emission Control Measures29
Data on the performance of coal combustion emission control
measures, relative to mercury and mercury compounds, are quite
sparse. Furthermore, many of the data that are available are
somewhat dated and are of questionable reliability.
Emission control measures for coal-fired boilers include
controls based on combustor design and operating practices that
are directed primarily at nitrogen oxides (NOX) and particulate
matter (PM) control and add-on air pollution control devices that
are designed for acid gas and PM control. .Those measures that
are most likely to affect mercury control are add-on control
systems designed for both PM and acid gas control. The primary
types of PM control devices used for coal combustion include
multiple cyclones, electrostatic precipitators, fabric filters •
(baghouses), and wet scrubbers, while both wet and dry flue gas
desulfurization (FGD) systems are used for sulfur dioxide (SC^) .
Some measure of PM control is also obtained from ash settling in
boiler/air heater/economizer dust hoppers, large breeches and
chimney bases, but these mechanisms will not reduce mercury
emissions.
Electrostatic precipitators (ESP) are the most common high
efficiency control devices used on pulverized coal and cyclone
units. These devices are also being used increasingly on
stokers. Generally, PM collection efficiencies are a function of
the specific collection area (i.e., the ratio of the collection
plate area per volumetric flow rate of flue gas through the
device). Particulate matter efficiencies of 99.9 weight percent
have been measured with ESP's. Fabric filters have recently seen
increased use in both utility and industrial applications both as
6-15
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a PM control measure and as the collection mechanism in dry FGD
systems, generally achieving about 99.8 percent PM control. Wet
scrubbers are also used to control PM emissions, although their
primary use is to control emissions of sulfur oxides. Because,
unlike the other PM control devices, wet scrubbers reduce the gas
stream temperature, they may be more effective than the other
controls in removing condensible PM, such as mercury. The other
PM control devices would require some type of acid gas control,
such as a spray dryer.
Mechanical collectors, generally multiple cyclones, are the
primary means of control on many stokers and are sometimes
installed upstream of high efficiency control devices in order to
reduce the ash collection burden. Depending on application and
design, multiple cyclone PM efficiencies can vary tremendously.
However, these systems are relatively inefficient for fine
particles and are not likely to provide measurable control of
mercury emissions, which are primarily in the vapor and fine
particle fractions of the exhaust.
The section on emission factors below presents the available
data on emission control system performance. However, in
evaluating the potential emissions from a facility or group of
facilities, any assumptions about control system performance,
including those based on the data presented herein, should be
examined carefully to assure that they are supported by reliable
test data obtained via methods comparable to those described in
Section 9. Also, performance estimates must be consistent with
the physical and chemical properties of the compounds being
emitted and with the operating characteristics of the systems
being evaluated.
6.1.4 Emissions .-..:..•: ..."
---The primary source of mercury emissions from coal combustion
operations is the combustion gas exhaust stack. ~Small amounts of
6-16
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mercury also may be emitted as a component of the fugitive PM
emissions from coal and ash handling.
Two distinct sources of information were used to develop and
evaluate mercury emission factors for coal combustion. A third
source was considered but was not used. First, the data
presented above on mercury concentrations in coal and coal
heating values were used to develop mass balance-based emission
factors under the conservative assumption that all mercury
charged with the coal is emitted in the stack gas. The
assumption is based on a lack of data on the effectiveness of
mercury controls for coal combustion. Second, the emission
factors presented in the coal and oil Locating and Estimating
(L&E) document were reviewed and summarized. ° No attempt was
made to verify the sources of data used in the coal and oil L&E
document or to rate the emission factors that were developed
therein. The results obtained from these two methods are
discussed separately in the paragraphs below. Then the relative
merits of the emission factors obtained by the different methods
are examined and the best typical emission factors are
identified. The third approach, using controlled emission
factors from a summary of the PISCES literature data base, was
considered, but those results are based on a much smaller number
of data points. Data were excluded as unreliable for a variety
of reasons, including uncharacteristically low ESP control
efficiencies, but the variability in the data did not improve
significantly.^
The information presented in the literature indicates that
virtually 100 percent of the mercury contained in the coal is
emitted from the furnace as either a vapor or fine PM.
Consequently, the coal heating values presented in Table 6-2 and
the coal mercury concentrations presented in Table 6-4 can be
used to develop emission factors for major coal types .under the
conservative assumption that all mercury in the coal. is.emitted.
Furthermore, note that the coal composition data in Table 6-4 are
6-17
-------
based on in-ground mercury concentrations and that calculated
emission factors shown in Table 6-6 are-based on the conservative
assumption that as-fired coal contains equivalent concentrations.
If mercury concentrations are reduced during coal cleaning
operations, these estimates will be biased high. The Utility Air
Regulatory Group (UARG) and the Electric Power Research Institute
(EPRI) are working with the USGS to compile data on the extent of
coal washing in the United States and its effects on the trace
metal content of coal. This study is expected to be completed by
the end of 1993. Preliminary data from the U.S. Department of
Energy indicates that there is reduction in mercury
concentrations from coal cleaning (10 to 25 percent for
commercial cleaning and 25 to 50 percent for laboratory
cleaning).34 The mercury emission factors derived from these
reduced mercury concentrations are also shown in Table 6-6.
TABLE 6-6. CALCULATED UNCONTROLLED MERCURY EMISSION
FACTORS FOR COAL COMBUSTION
Coal type
Bituminous''
Subbituminousc
Anthracited
Lignite8
Calculated mercury emission factors3
kg/1015J
7.0 (5.2-6.3)
4.5 (2.9-4.0)
7.6 (5.7-6.8)
9.0 (6.8-8.1)
lb/1012Btu
16 (12-14)
10 (7.5-9.0)
18 (14-17)
21 (16-19)
g/Mg coal
0.21 (0.16-0.19)
0.10 (0.075-0.090)
0.23 (0.17-0.21)
0.15 (0.11-0.14)
10~3 Ib/ton coal
0.42 (0.32-0.38)
0.20 (0.15-0.18)
0.46 (0.34-0.41)
0.30 (0.22-0.27)
3Values in parenthesis are based on a 10 to 25 percent reduction in mercury concentrations from
commercial coal cleaning.
bBased on arithmetic .average of the five average heating values in Table 6-2.
cBased on arithmetic average of the three average heating values in Table 6-2.
dBased on average heating value for coal category A2 in Table 6-2.
eBased on average heating value for coal category L1 in Table 6-2.
A comprehensive summary of the test data generated prior to
1989 for coal-fired boilers and furnaces is presented in ' .
Reference 26. The data from individual tests that are presented
6-18
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in that report are compiled in Table B-l in Appendix B.
Table 6-7 summarizes these data as a function of coal type and
control status. Note the wide range of emission factors for each
coal type. In addition to the variability in coal heat content
and the uncertainty in mercury sampling and analysis, this range
reflects the substantial variation in coal mercury content and
highlights the need to obtain coal-specific mercury data to
calculate emission estimates whenever possible. Also note that
the data are combined across industry sector and boiler type
because these parameters are not expected to have a substantial
effect on emission factors.
As noted in Reference 26, the available test data, although
limited, indicate that essentially no control of mercury in flue
gas is achieved by multiclones, up to 50 percent control is
achieved by ESP'3, and limited scrubber data show mercury
efficiencies of 50 and 90 percent. Long-term scrubber
performance will depend on the blowdown rate for the scrubber,
with efficiency falling if the system approaches equilibrium.
However, according to literature references discussed in
Reference 26, these control efficiencies may be biased high
because they are based on data collected using older test
methods, which tended to collect mercury vapor inefficiently.
Consequently, these estimates represent upper bounds of
efficiencies. More information on the sampling and analysis of
mercury in flue gas is presented in Section 9.
Based on review of the available data, the best estimates
for uncontrolled emission factors for typical coal combustion
facilities are those obtained from a mass balance using coal
composition data. This approach was selected because the
available test data are of uncertain quality, and the coal
concentration data are representative of a much larger industry
segment. Controlled emission factors were obtained by applying
an assumed 0 percent efficiency for mechanical collectors, 0 to
50 percent control for ESP's, and 50 to 90 percent control for
6-19
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TABLE 6-7. MEASURED MERCURY EMISSION FACTORS FOR COAL COMBUSTION
Coal
type8
Bd
Bd
Bd
Bd
Bd
Bd
SB6
SBe
SB8
L»
L'
Afl
•
. Control
statue"
UN
MPor
MC
ESP or
MP/ESP
ESP-2
stage
WSor
MC/WS
FF
UN
ESP or
MP/ESP
WS
MC
ESP
UN
No.
of
boilers
17
9
29
1
5
1
3
3
2
4
3
3
No. of
data
points
34
16
59
5
6
1
5
5
2
4
3
3
Measured mercury emission factors
kg/1015 J
Mean
3.8
12.9
3.4
0.086
7.9
2.0
13.0
1.2
3.4
4.1
0.18
2.3
Range0
0.005-133
0.60-77
0.18-9.6
0.005-0.25
b.d.-37
--
0.28-35
0.16-1.8
2.1-4.7
1.9 9.5
0.099-0.23
1.5-3.0
lb/1012Btu
Mean
8.8
29.9
8.0
0.20
18.4
4.6
30.2
2.7
•
8.0
9.6
0.41
5.3
Range0
0.011-308
1.4-180
0.41-22.3
0.011-0.56
b.d.-86
-
0.64-81
0.37-4.1
4.9-11
4.4-22
0.23-0.53
3.5-7.0
g/Mg coald
Mean
0.11
0.39
0.10
0.0026
0.24
0.060
0.29
0.027
0.075
0.068
0.0030
0.070
Range0
0.00015-4.0
0.018-2.3
0.0055-0.29
0.00015-0.0075
b.d.-l.l
-
0.0062-0.78
0.0035-0.040
0.047-0.10
0.032-0.16
0.0016-0.0038
0.046-0.091
10'3lb/toncoale
Mean
0.23
0.78
0.21
0.0052
0.48
0.12
0.68
0.052
0.15
0.14
0.0069
0.14
Range6
0.00029-8.0
0.036-4.7
0.011-0.58
0.00029-0.016
b.d.-2.2
-
0.012-1.6
0.0071-0.078
0.094-0.21
0.0630.32
0.0033-0.0076
0.091-0.18
a\
i
to
o
Source: Reference 26.
aB = bituminous, SB = subbituminous, L = lignite, A = anthracite.
UN = uncontrolled, MP = mechanical precipitation system, MC = multiclone, ESP = electrostatic precipitator, WS =wet scrubber.
cb.d. = below detection limits.
dBased on arithmetic average of the five average heating values in Table 6-2.
eBased on arithmetic average of the three average heating values in Table 6-2.
'Based on average heating value for coal category Li in Table 6-2.
OBased on average heating value for coal category A2 in Table 6-2.
-------
wet scrubbers. Data were inadequate to estimate efficiencies for
systems equipped with fabric filters. The resultant best typical
emission factors are shown in Table 6-8.
The ESP-controlled emission factors for bituminous,
subbituminous, and lignite coal were compared with the median and
mean ESP-controlled emission factors summarized from the PISCES
data base.33 For bituminous and subbituminous coals, the
emission factors for mercury presented in this L&E were in the
same range as those from PISCES. The mercury emission factor
presented here for lignite coals was higher than that from PISCES
by almost two orders of magnitude. However, the PISCES results
are based on a much smaller number of samples due to the
exclusion of data considered unreliable. The variability in the
PISCES data was not improved significantly with the exclusion.
The mercury emission factors presented for coal combustion
should be viewed as the most realistic nationwide estimates
possible, based on what little data are available. It should be
recognized that, as with the PISCES data, there is considerable
uncertainty in these estimates. The uncertainty in the L&E
estimates is due to the wide variability in mercury
concentrations in coal, the variability in coal heat content, and
the uncertainty in sampling and analytical methodologies for
detecting mercury. Therefore, these estimates should not be used
to determine emissions from specific coal combustion facilities.
6.2 FUEL OIL COMBUSTION
s
As shown in Table 6-1, based on energy consumption estimates
by the U.S. Department of Energy, fuel oil use spans the four
sectors of energy users. Distillate fuel oil is used extensively
in all sectors with the largest use in the utility (31 percent)
and the industrial (32 percent) sectors, but with substantial
amounts used in both the commercial (13 percent) and residential
(23 percent) sectors. Residual oil is used primarily in the
6-21
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TABLE 6-8. BEST TYPICAL MERCURY EMISSION FACTORS FOR COAL COMBUSTION
Coal
type3
B
B
B
B
Control statusb
Uncontrolled
Mechanical collector
ESP
Wet scrubber
Typical mercury emission factors
kg/1015 J
7.0
7.0
3.5-7.0
0.7-3.5
lb/1012 Btu
16
16
8-16
1.6-8
SB
SB
SB
SB
Uncontrolled
Mechanical collector
ESP
Wet scrubber
4.5
4.5
2.2-4.5
0.4-2.2
10
10
5-10
1-5
A
A
A
A
Uncontrolled
Mechanical collector
ESP
Wet scrubber
7.6
7.6
3.8-7.6
0.7-3.8
18
18
9-18
1.8-9
L
L
L
L
Uncontrolled
Mechanical collector
ESP
Wet scrubber
9.0
9.0
4.5-9.0
0.9-4.5
21
21
10-21
2.1-10
g/Mg coal
0.21
0.21
0.10-0.21
0.021-0.10
10'3 Ib/ton
coal
0.42
0.42
0.21-0.42
0.042-0.21
0.10
0.10
0.050-0.10
0.010-0.050
0.20
0.20
0.10-0.020
0.02-0.10
0.23
0.23
0.12-0.23
0.023-0.12
0.46
0.46 '
0.23-0.46
0.046-0.23
*
0.15
0.15
0.075-0.15
0.015-0.075
0.30
0.30
0.15-0.30
0.030-0.15
3B = bituminous, SB = subbituminous, A = anthracite, L = lignite.
ESP = electrostatic precipitator.
6-22
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industrial (56 percent) and commercial (33 percent) sectors.
Because the oil combustion process is not complex, and control
systems are not widely applied to oil-fired units, the discussion
below will focus on fuel characteristics and on emissions from
oil-fired units.25
6.2.1 Fuel Oil Characteristics26
*
The fuel oil characteristics of greatest importance for
characterizing .mercury emissions from fuel oil combustion are the
heating value and the mercury content of the oil. The heating
value is used for converting from emission factors with mass- or
volume-based activity levels to those with activity levels based
on heat input.
•
The term fuel oil covers a variety of petroleum products,
including crude petroleum, lighter petroleum fractions such as
kerosene, and heavier residual fractions .left after distillation.
To provide standardization and means for comparison,
specifications have been established that separate fuel oils into
various grades. Fuel oils are graded according to specific
gravity and viscosity, with No. 1 Grade being the lightest and
No. 6 the heaviest. The heating value of fuel oils is expressed
in terms of kJ/L (Btu/gal) of oil at 16°C (60°F) or kJ/kg
(Btu/lb) of oil. The heating value per gallon increases with
specific gravity because there is more weight per gallon. The
heating value per mass of oil varies inversely with specific
gravity because lighter oil contains more hydrogen. For an
uncracked distillate or residual oil, heating value can be
approximated by the following equation:
Btu/lb =17,660 + (69 x API gravity)
6-23
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For a cracked distillate, the relationship becomes:
Btu/lb = 17,780 + (54 x API gravity)
Table 6-9 provides an overall summary of the heating values
of typical fuel oils used in the U.S., and Table 6-10 shows the
variability in fuel oil heating values used in various regions of
the country. Appendix B of Reference 26 provides additional
details.
The data base for mercury content in fuel oils is much more
limited than the coal mercury content data base. A number of
petroleum industry associations were contacted, but none who
responded have done any research on metals content in fuel oils.
•
No single centralized data base is available, and the information
presented below is based on limited data from individual studies.
Concentrations of mercury in fuel oil depend upon the type
of oil used. No comprehensive oil characterization studies have
been done, but data in the literature report mercury
concentrations in crude oil ranging from 0.023 to 30 ppmwt, while
the range of concentrations in residual oil is 0.007 to
0.17 ppmwt. Because only a single mean value was found in the
literature for mercury concentration in distillate oil, no
conclusions can be drawn about the range of mercury in distillate
oil. Table 6-11 lists typical values for mercury in oils, which
were obtained by taking the average of the mean values found in
the literature. The value for distillate oil is the single data
point found in the literature and may not be as representative as
the values for residual and crude oils.
6.2.2 Process Description29'32
Fuel oils are broadly classified into two major types:
distillate and residual. Distillate oils (fuel oil'grade
Nos. I and 2) are more volatile and less viscous than residual
6-24
-------
TABLE 6-9. TYPICAL HEATING VALUES OF FUEL OILS
Type
Color
Heating value8
kJ/L
(Btu/gal)
kJ/kg
(Btu/lb)
FUEL OIL GRADES
No. 1
Distillate
Light
38,200
(137,000)
45,590-46,030
(19,670-19,860)
No. 2
Distillate
Amber
40,900
(141,000)
44,430-45,770
(19,170-19,750)
No. 4
Very light residual
Black
40,700
(146,000)
42.370-44,960
(18.280-19,400)
No. 5
Light residual
Black
41,200
(148,000)
41,950-44,080
(18,100-19,020)
No. 6
Residual
Black
41,800
(150,000)
40,350-43,800
(17,410-18,900)
Crude6
40,000-42,300
(144,000-152,000)
40,700-43,300
(17,500-18,600)
a\
t
to
in
Source: References 26 and 35.
aThe distillate samples, as well as the residual samples, analyzed for Btu/gal and Btu/lb heating values are different; therefore, the heating values presented do not
directly correspond .to one another.
"These crude oil values are based on a limited number of samples fiom West Coast field sites presented in Reference 34 and may not be representative of the
distribution of crude oils processed in the United States.
-------
TABLE 6-10. TYPICAL FUEL OIL HEATING VALUES FOR SPECIFIC REGIONS
Region
Eastern
Southern
Contra!
Rocky
Mountain
Western
No. 1 fud oil
Heating value, kJrt. (Btu/gall
No. of
samples
33
13
27
14
10
Range
36.800-37.800
<132,6OO-136,700|
37.0OO-37.7OO
1132.800-136.400)
36.800-37.800
. 1132.600-136.7001
37.1OO-37,6OO
1133,100-136.1001
36.700-37,800
I13I.70O-136.20OI
Average
37,400
1134,200)
37,400
1134.300)
37.3OO
(134.000)
37,400
1134.200)
37.60O
(134.600)
No. 2 lud oil
Heating value. kJ/t (Btu/gall
No. of
•amplea
66
18
3E
17
18
Range
37.100-40,800
(133.100-146,600)
38,000-38,400
(136.400-141.600)
37.800-40,800
(136.800-146.600)
37.800-39,100
(136.100-140,400)
37,800-38.100
(136.100-140.600)
Average
38.800
1138.600)
38.800
I138.4OOI
38,800
(138,200)
38.700
1138.000)
38.700
(139.OOOI
No. 4 lud oil
Heating value, kJ/L (Btu/gal)
No. ol
samples
1
0
2
2
0
Range
:
„
40.700-41.800
I146.00O-160.1OOI
41.800-41,800
1160.100-160.600)
--
Average
40.70O
1148.0001
-
41.200
. (148.000) .
41.800
1160.3001
37.600
(134,6001
a\
i
to
a\
Region
Eastern
Southern
Central
Rocky
Mountain
Western
No. 6 lud oil (light!
Heating vdua. kJ/L IBlu/gal)
No. ol
•amplea
1
0
4
2
0
Range
-
:
41.300-42,200
(148.400-161,600)
42,800-43,600
11 63.800-1 66.6OOI
•-
Average
41.300
(148.4OO)
I
41,700
1148.8001
43.200
(166,2001
...
No. 6 lud oil
Hawing value. kJ/L (Blu/gall
No. ol
samples
17
14
10
7
12
Range
40.9OO 43.900
I147.OOO-167.600I
41.800-43.600
(160,600-166,600)
41. 9OO 44.2OO
(160.600-168.800)
42.300-44,300
(161,800-168,200)
41.700-46.600
148.800-163.6001
Average
43,300
1161,8001
42,600
(162.800)
42.600
1162,800)
43.100
(164,600)
43.000
(164.400)
Source: Reference 26.
-------
TABLE 6-11. MERCURY CONCENTRATION IN OIL BY OIL TYPE
Fuel oil type
Residual No. 6
Distillate No. 2
Crude
No. of samples
14
1
46
Mercury concentration, ppmwt
Range
0.007-10
—
0.007-30
Typical value
0.0563
0.40b
3.5C
Source: Reference 26.
aAverage of 14 data points with 10 ppm concentration discarded as an outlier.
bBased on single data point. May not be representative.
cAverage of 46 data points was 6.86; if the single point value of 23.1 is eliminated, average based
on 45 remaining data points is 1.75. However, the largest study with 43 data points had an
average of 3.2 ppmwt. A compromise value of 3.5 ppmwt was selected as the best typical
value.
oils, having negligible ash and nitrogen contents and usually
containing less than 0.1 weight percent sulfur. No. 4 residual
oil is sometimes classified as a distillate; No. 6 is sometimes
referred to as Bunker C. Being more viscous and less volatile
than distillate oils, the heavier residual oils (Nos. 5 and 6)
must be heated to facilitate handling and proper atomization.
Because residual oils are produced from the residue after lighter
fractions (gasoline and distillate oils) have been removed from
the crude oil, they contain significant quantities of ash,
nitrogen, and sulfur. Small amounts of crude oil are sometimes
burned for steam generation for enhanced oil recovery or for
refinery operations.
Oil-fired boilers and furnaces are simpler and have much
less variation in design than the coal-fired systems described
earlier. The primary components of the system are the burner,
which atomizes the fuel and introduces it along"with the
combustion air into the flame, and the furnace, which provides
the residence time and mixing needed to complete combustion of
the fuel. The primary difference in systems that fire distillate
6-27
-------
oil and residual oil is that the residual oil systems must have
an oil preheater to reduce the viscosity of the oil so that it
can be atomized properly in the burner. Systems that fire
distillate oil and residual oil also have different atomization
methods.
The only source of mercury emissions from oil-fired boilers
and furnaces is the combustion stack. Because the entire fuel
supply is exposed to high flame temperatures, essentially all of
the mercury and mercury compounds contained in the fuel oil will
be volatilized and exit the furnace with the combustion gases.
Unless these combustion gases are exposed to low-temperature air
pollution control systems and high-efficiency PM control systems,
which typically are not found on oil-fired units, the mercury and
mercury compounds will be exhausted in vapor phase through the
combustion stack.
6.2.3 Emission Control Measures26'32
The three types of control measures applied to oil-fired
boilers and furnaces are boiler modifications, fuel substitution,
and flue gas cleaning systems. Only fuel substitution and flue
gas cleaning systems will affect mercury emissions. Fuel
substitution is used primarily to reduce S02 and NOX emissions.
However, if the substituted fuels have lower mercury
concentrations, the substitution will also reduce mercury
emissions. Because PM emissions from oil-fired units are
generally much lower than those from coal-fired units,
high-efficiency PM control systems are generally not employed on
oil-fired systems. Consequently, these flue gas cleaning systems
are not likely to achieve substantial mercury control. However,
the flue gas cleaning systems that are used on oil-fired units
are described briefly below. "-"." '~~ '•'••-'"'
.Flue gas cleaning equipment generally is employed only oh
larger oil-fired boilers. Mechanical collectors, a prevalent
6-28
-------
type of control device, are primarily useful in controlling PM
generated during soot blowing, during upset conditions, or when a
very dirty heavy oil is fired. During these situations, high
efficiency cyclonic collectors can achieve up to 85 percent
control of PM, but negligible control of mercury is expected with
mechanical collectors.
Electrostatic precipitators are commonly used in oil-fired
power plants. Older ESP's may remove 40 to 60 percent of the PM,
but negligible mercury control is expected. Newer ESP's may be
more efficient, but no data are available for oil-fired power
plants. Scrubbing systems have been installed on oil-fired
boilers to control both sulfur oxides and PM. Similar to systems
applied to coal combustion (presented in Reference 26), these
systems can achieve PM control efficiencies of 50 to 90 percent.
Because they provide gas cooling, some mercury control may be
obtained, but no data are available on their performance.
6.2.4 Emissions •
The only substantive source of mercury emissions from fuel
oil combustion operations is the combustion gas exhaust stack.
Three types of information were used to develop emission factors
for oil combustion. First, the data described above on fuel oil
heating value and mercury content of fuel oils were used to
develop emission factors by mass balance, assuming conservatively
that all mercury fired with the fuel oil is emitted through the
stack. Second, the emission factors from the coal and oil L&E
document were evaluated and summarized, but no attempt was made
to verify original references or to rate these data. Finally,
rated emission test data developed in preparation of this
document were evaluated and summarized. The paragraphs below
first present the results generated from each of the three
sources. Then, the relative merits of the emission factors
generated via each of the procedures are discussed, and the best
"typical" emission factors are identified.
6-29
-------
The literature on fuel oil .combustion suggests that
essentially all mercury in the fuel oil .is vaporized in the
combustion zone and exhausted as a vapor in the combustion gas
stream. Using the assumption that 100 percent of the mercury in
fuel oil leaves the boiler or furnace in the exhaust gases, the
data in Tables 6-9 and 6-11 were used to calculate uncontrolled
emission factors for No. 2 distillate and No. 6 residual oil.
Data presented in Reference 34, which show average crude oil
heating values of 42,500 kJ/kg (18,300 Btu/lb) and 41,300 JcJ/L
(148,000 Btu/gal), can be combined with the mercury content data
in Table 6-11 to calculate uncontrolled emission factors for
crude oil combustion. The results of these calculations are
presented in Table 6-12.
TABLE 6-12. CALCULATED UNCONTROLLED MERCURY EMISSION FACTORS
FOR FUEL OIL COMBUSTION
Fuel oil type
Residual No. 6a
Distillate No. 2a
Crudeb
Calculated mercury emission factors
kg/1015 J
1.4-
8.8
84
lb/1012 Btu
3.3
21
190
g/Mg
fuel oil
0.056
0.40
3.5
10'3 Ib/ton
fuel oil
0.11
0.80
7.0
g/103L
fuel oil
0.058
0.36
3.5
lb/106 gal
fuel oil
0.50
3.0
28
aBased on typical heating values in Table 6-9 and mercury concentrations in Table 6-11.
^Based on average crude oil heating values in Reference 35 and mercury concentrations
in Table 6-11.
A comprehensive summary of the emission data generated prior
to 1989 was prepared by Brooks.26 These somewhat dated results
are tabulated in Table 6-13. Note that both the residual and
distillate values presented in Table 6-13 are consistently less
than the calculated values presented in Table 6-12. Brooks noted
that for-those tests for which data were sufficient to calculate
.mercury input rates, the measured emissions ranged from 3 to
20 percent of the mercury in the fuel.26 Mercury is quite
volatile and is expected to be emitted from the combustion
process as a vapor. These results suggest that the emission test
6-30
-------
TABLE 6-13. MEASURED MERCURY EMISSION FACTORS FOR FUEL OIL COMBUSTION
Fuel type
Residual No. 6
Residual No. 6
Residual No. 6
Residual No. 6
Residual No. 6
1:1 Residual No. 6/Crude
1:1 Residual No. 6/Cruda
1:1 Residual No. 6/Crude
Distillate No. 2°
Distillate No. 2°
Distillate No. 2a
i
Industry
sector8
1
1
1
1
1
U
u
U
R
R
R
Control
statusb
MC/WS
MC
UN
UN
UN
UN
UN
UN
UN
UN
UN
Fuel Hg
content,
ppmwt
—
~_
<0.01
<0.01
<0.01
0.04
0.03
0.04
_.
0.4
0.4
Measured mercury emission factors
kg/1015 J
0.099
0.60
0.47
0.47
0.0 IB
0.056
0.031
0.022
1.2
6.0
7.3
lb/1012 Btu
0.23d
1.4d
1.1
1.1
0.037
0.13
0.072
O.OS2
2.8(
14
17
g/Mg
fuel oil0
0.0042
0.025
0.020
0.020
0.00067
0.0024
0.0013
0.00093
0.054
0.27
0.33
10'3 Ib/ton
fuel oilc
0.0084
0.051
0.040
0.040
0.0013
0.0047
0.0026
0.0019
0.11
0.54
0.66
g/103L
fuel oilc
0.0041
0.025
0.020
0.020
0.00067
0.0024
0.0013
0.00093
0.049
0.25
0.30
lb/106 gel
fuel oil0
0.034
0.21
0.16
0.16
0.0056
0.019
0.011
0.0077
0.39
2.0
2.4
Date
1979
1979
1978
1978
1978
1981
1981
1981
1979
1981
1981
a\
i
u>
M
Source: Reference 26.
al = Industrial, U = utility, R = residential.
bMC = multiclone, WS = wet scrubber, UN = uncontrolled.
°Based on typical residual and distillate fuel oil heating values in Table 3-9 and average crude oil heating values in Reference 10,
•Values obtained at outlet from and inlet to a wet scrubber at a single facility.
"Type of distillate oil not specified.
Average of eight tests on seven units.
-------
results are biased low, probably because they were collected
using older test methods, in which the impinger solutions in the
sampling train captured mercury vapors inefficiently.
Consequently, the test data in Table 6-13 should be used
cautiously. More information on the sampling and analysis of
mercury in fuel oil is presented in Section 9.
As a part of this study, three test reports prepared as a
part of the California "Hot Spots" program were reviewed.35-37
The emission factors generated from these three reports are
summarized in Table 6-14. Each of the reports contained the data
on fuel oil characteristics needed to calculate mercury input
rates, so Table 6-14 contains both calculated emission factors
based on mercury input levels and measured emission factors based
on stack tests. Because mercury levels in all of the fuel oils
tested were below detection limits, all calculated emission
factors are reported as "less than" values. Note that only one
of the three tests showed mercury levels above the detection
limit in the stack. That test showed measured emissions to be
substantially greater than mercury input to the process, making
the results suspect. These discrepancies may be a function of
the analytical problems that have been reported for mercury
methods applied to combustion sources. These problems are
discussed in more detail in Section 9. On balance, these data
provide little information for emission factor development.
Given the limited emission test data available and the
concerns about possible biases in those data, the mass balance
approach was used to estimate the best "typical" emission factor
for distillate and residual fuel oil combustion. Because only a
single data point was available for distillate oil, the data in
Table 6-11 were used to develop a weighted average mercury
concentration in distillate and residual oils of 0.13 ppmwt.
This concentration was combined with the average heating values
shown in Table 6-9 to obtain the best estimate of typical :
emission factors for distillate and residual"oil combustion.
6-32
-------
TABLE 6-14. MERCURY EMISSION FACTORS FOR FUEL OIL COMBUSTION
GENERATED FROM CALIFORNIA "HOT SPOTS" TESTS
Process
type
Pipeline/
process
heater11
Generator0
Power
boilard
Fuel
oil
type
Crude
Crude
Residual
Calculated mercury emission factors"
kg/1016
J
<2.4
<2.4
<2.3
lb/1012
Btu
<6.6
<6.6
<6.6
g/Mg
(uel
oil
<0.10
<0.1O
<0.10
ID'3
Ib/ton
fuel
oil
<0.20
<0.21
<0.21
g/103L
fuel
oil
<0.097
<0.10
<0.10
lb/106
gal
fuel
oil
OJ
Source: Reference* 36-37.
*For crude oil. emission factors were based on assumed crude oil heating value of 42,600 kJ/kg (18,300 Btu/lb) and density of 0.97 kg/L (8.1 Ib/gal). For residual oil. emission factors
were based on residual oil heating value of 43.6OO kJ/kg (18.800 Btu/lb) and density of 0.98 kg/L (8.2 Ib/gal).
bMercury detection limit is 0.1 mg/kg.
cMorcury detection limit is 0.1 mg/L.
dMorcury detection limit is 0.1 mg/L.
-------
The available information on uncontrolled mercury emissions
from crude oil combustion is ambiguous. The limited test data
presented in Tables 6-13 and 6-14 show measured factors that
range from 0.02 to 15 kg/1015 J (0.05 to 34 lb/1012 Btu), a range
of almost three orders of magnitude. The calculated emission
factor of 84 kg/1015 J (190 lb/1012 Btu), which is "based on
limited fuel composition and heating value data, expands the
range even further. Because these data are quite sparse and the
relative quality of the data is uncertain, the midpoint of the
range was selected as the best "typical" emission factor.
The uncontrolled emission factors for distillate, residual,
and crude oil are presented in Table 6-15. Data are insufficient
to develop controlled emission factors for fuel oil combustion.
There is considerable uncertainty in these emission factor
estimates due to the variability of mercury concentrations in
fuel oil, the incomplete data base on distillate oil, and the
uncertainty in sampling and analysis for detecting mercury.
Therefore, these estimates should not be used to determine
emissions from specific oil-fired units.
TABLE 6-1 5. BEST TYPICAL MERCURY EMISSION FACTORS FOR FUEL OIL COMBUSTION
Fuel oil type
Residual No. 6
Distillate No. 2
Crude
Typical mercury emission factors
kg/1015 J
3.0
2.9
41
lb/1012 Btu
7.2
6.8
95 •
g/Mg
fuel oil
0.13
0.13
1.7
10"3 Ib/ton
fuel oil
0.26
0.26
3.5
g/103 L
fuel oil
0.12
0.12
1.7
lb/106 gal
fuel oil
1.1
0.96
14
6.3 NATURAL GAS COMBUSTION
Natural gas is one of the major fuels used throughout the
country. As shown in Table 6-1, natural gas is used as an energy
source in all four sectors, but the greatest uses are in the
6-34
-------
industrial (46 percent) and residential (15 percent)' sectors.
The five States that consume the largest quantities of natural
gas are Texas, California, Louisiana, Illinois, and New York.
However, only Louisiana and Oklahoma consume more energy via
natural gas combustion than by either coal or petroleum products
combustion. ^
6.3.1 Natural Gas Characteristics31'38
Natural gas is considered to be a clean fuel. It consists
of primarily methane (generally 80 percent or greater by mass),
along with varying amounts of ethane, propane, butane, and inert
material (typically nitrogen, carbon dioxide, and helium). The
average heating value of natural gas is about 8,900 kilocalories
per standard cubic meter (kcal/scm)(1,000 Btu per standard cubic
foot [Btu/scf]), with levels ranging from 8,000 to 9,000 kcal/scm
(900 to 1,100 Btu/scf). No data are available on the mercury
content of natural gas. However, concentrations are expected to
be quite low. Little mercury is -expected to be found in raw gas,
and the processing steps used to recover liquid constituents and
to remove hydrogen sulfide from the raw gas should remove mercury
that is contained in the raw gas.
6.3.2 Process Description38
Natural gas combustion sources can be divided into four
categories: utility/large industrial boilers, small industry
boilers, commercial boilers, and residential furnaces. These
systems are configured differently, but the combustionNprocesses
are comparable for all categories. The natural gas and
combustion air are mixed in a burner and introduced to a
combustion chamber via a flame. The natural gas flame
temperature, which exceeds 1000°C (1832°F), will volatilize any
mercury or mercury compounds in the fuel. The compounds will
then be exhausted as a vapor from the boiler "or furnace with.the
6-35
-------
combustion gas stream. This exhaust stream is the only source of
mercury emissions fronrnatural gas' combustion.
6.3.3 Emission Control Measures
No control measures applied to natural gas-fired boilers and
furnaces are expected to affect mercury emissions.
6.3.4 Emissions
The only source of mercury emissions from natural gas
combustion is the combustion gas exhaust stack, and mercury
emissions from this source are expected to be minimal. Data on
mercury emissions from natural gas combustion are very limited.
One reference reported an emission factor of 4.-9 kg/1015 J
(11.3 lb/1012 Btu) for both tangential-fired and wall-fired
boilers based on emission test data.39 However, this emission
factor seems unlikely in that it would require the concentration
of mercury in natural gas-to be 0.27 ppmwt, a concentration that
is of the same order of magnitude as coal and fuel oil. Given
the processing steps that natural gas undergoes, this
concentration does not seem feasible. Consequently, the emission
factor presented above is not considered to be reliable, and no
emission factor is recommended for mercury.
6.4 WOOD COMBUSTION
Wood and wood wastes are used as fuel in both the industrial
and residential sectors. In the industrial sector, wood waste is
fired to industrial boilers to provide process heat, while wood
is fired to fireplaces and wood stoves in the residential
sectors. The information below includes process descriptions for
the three combustion processes (boilers, fireplaces, and wood
stoves),.descriptions of the control measures used for wood-fired
processes, and emission factors.
6-36
-------
6.4.1 Process Description38'40
Wood waste combustion in boilers is mostly confined to those
industries for which it is available as a byproduct. These
boilers generate energy and alleviate possible solid waste
disposal problems. In boilers, wood waste is normally burned in
the form of hogged wood, sawdust, shavings, chips, sanderdust, or
wood trim. Heating values for this waste range from about 2,200
to 2,700 kcal/kg (4,000 to 5,000 Btu/lb) of fuel on a wet,
as-fired basis. The moisture content is typically near 50 weight
percent but may vary from 5 to 75 weight percent, depending on
the waste type and storage operations. Generally, bark is the
major type of waste burned in pulp mills; either a mixture of
wood and bark waste or wood waste alone is burned most frequently
in the lumber, furniture, and plywood industries. A State of
Washington study in 1990 found the mercury content in bark waste
to range from <0.08 to 0.84 ppmwt.40
As of 1980, approximately 1,600 wood-fired boilers were
operating in the U.S., with a total capacity of over
30 gigawatts(GW) (1.0 x 1036 Btu/hr). No specific data on the
distribution of these boilers were identified, but most are
likely to be located in the Southeast, the Pacific Northwest
States, Wisconsin, Michigan, and Maine.
The most common firing method employed for larger wood-fired
boilers is the spreader stoker. Wood enters the furnace through
a fuel chute and is spread either pneumatically or mechanically
across the furnace, where small pieces of the fuel burn while in
suspension. Simultaneously, larger pieces of fuel are spread in
a thin, even bed on a stationary or moving grate. Natural gas or
oil is. often fired in spreader stoker boilers as auxiliary fuel
to maintain a constant steam supply when the wood waste supply or
composition fluctuates. Auxiliary fuel allows more steam to be
generated than is possible from the waste supply alone.
6-37
-------
Another boiler type sometimes used for wood combustion is
the suspension-firing boiler. This boiler differs from a
spreader stoker in that small-sized fuel (normally less than
2 mm) is blown into the boiler and combusted by suspension firing
in air rather than on fixed grates. Rapid changes in combustion
rate and, therefore, steam generation rate are possible because
the finely divided fuel particles burn very quickly.
Wood stoves are commonly used in residences as space
heaters, both as the primary source of residential heat and to
supplement conventional heating systems. The three different
categories of wood stoves are:
The conventional wood stove;
• The noncatalytic wood stove; and
The catalytic wood stove.
The conventional stove category comprises all stoves without
catalytic combustors not included in the other noncatalytic
categories (i.e., noncatalytic and pellet). Conventional stoves
do not have any emissions reduction technology or design features
and, in most cases, were manufactured before July 1, 1986.
Stoves of many different airflow designs may be in this category,
such as updraft, downdraft, crossdraft, and S-flow.
Noncatalytic wood stoves are those units that do not employ
catalysts but do have emission-reducing technology or features.
Typical noncatalytic design includes baffles and secondary
combustion chambers.
Catalytic stoves are equipped with a ceramic or metal
honeycomb device (called a combustor or converter) that is coated
with a noble metal such as platinum or palladium. The catalyst
material reduces the ignition temperature of the unburned
volatile organic compounds (VOC's) and carbon monoxide ..(CO) in
6-38
-------
the exhaust gases, thus augmenting their ignition and combustion
at normal stove operating temperatures.
Fireplaces are used primarily for aesthetic effects and
secondarily as a supplemental heating source in houses and other
dwellings. Wood is the most common fuel for fireplaces, but coal
and densified wood "logs" may also be burned. The user
intermittently adds fuel to the fire by hand.
All of the systems described above operate at temperatures
that are above the boiling point of mercury and mercury
compounds. Consequently, any mercury contained in the fuel will
be emitted with the combustion gases. The combustion exhaust
stack is the only source of mercury emissions from these
processes.
6.4.2 Emission Control Measures38
Although some wood stoves use control measures to reduce VOC
and CO emissions, these techniques are not expected to affect
mercury emissions. However, wood waste boilers do employ PM
control equipment, which may provide some reduction. These
systems are described briefly below.
Currently, the four most common control devices used to
reduce PM emissions from wood-fired boilers are mechanical
collectors, wet scrubbers, ESP's, and fabric filters. Of these
controls, only the last three have the potential for significant
mercury reduction.
The most widely used wet scrubbers for wood-fired boilers
are venturi scrubbers. With gas-side pressure drops exceeding
4 kilopascals (15 inches of water), PM collection efficiencies of
90 percent or greater have been reported for venturi scrubbers
operating on wood-fired boilers. No data were located on the
performance of these systems relative to mercury emissions.
6-39
-------
However, some control is expected (probably in the range of
50 to 90 percent) based on results achieved for coal combustion
sources.
Fabric filters (i.e., baghouses) and ESP's are employed when
PM collection efficiencies above 95 percent are required.
Collection efficiencies of 93 to 99.8 percent for PM have been
observed for ESP's operating on wood-fired boilers, but mercury
efficiencies are likely to be substantially less (probably
50 percent less) based on the performance of ESP's in controlling
mercury from coal combustion sources. The performance of ESP's
in controlling mercury depends on temperature and the amount of
carbon in the fly ash. Fabric .filters have had limited
applications to wood-fired boilers because of fire hazards.
Despite complications, fabric filters are generally preferred for
boilers firing salt-laden wood. This fuel produces fine PM with
a high salt content for which fabric filters can achieve high
collection efficiencies. In two tests of fabric filters
operating on salt-laden wood-fired boilers, PM collection
efficiencies were above 98 percent. No data are available on
mercury emission reduction for fabric filters, but results for
other combustion sources suggest that efficiencies will be low,
probably 50 percent or less, depending on temperature and the
carbon content of the fly ash.
6.4.3 Emissions
The primary source of mercury emissions from wood combustion
processes is the combustion gas exhaust stack. Small quantities
of mercury also may be emitted with the fugitive PM emissions
from bottom and fly ash handling operations.
The data on mercury emissions from wood combustion are quite
limited. A recent study to update the wood waste combustion
section-of AP-42 and a report from the National Council of the
Paper Industry for Air and Stream Improvement provided a range
6-40
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TABLE 6-16. SUMMARY OF MERCURY EMISSION FACTORS FOR WOOD COMBUSTION
Operation
Wood waste boiler3
Residential wood stove-
conventional
Mercury emission factors
1 0"3 g/Mg wood burned
Range
1.3-10
—
Mean
3.4
130
10~6 Ib/ton wood burned
Range
2.6-21
~
Mean
6.7
260
. Source: References 40-42.
3Based on an assumed heating value of 10,460 kJ/kg (4,500 Btu/lb) and PM control.
and average typical emission factor for wood waste combustion in
boilers based on the results of eight tests.40'41 Table 6-16
presents the range and average obtained from those tests. The
average is recommended as the best typical emission factor for
wood waste combustion.
A review of the .literature produced, one emission factor for
residential wood combustion.4^ This factor, which was based on a
single test at one location, is also presented in Table 6-16.
Because mercury content in wood may vary with local soil
conditions, this single value may not be representative of
conditions across the U.S. and should be used cautiously.
6.5 MUNICIPAL WASTE COMBUSTION
Refuse or municipal solid waste (MSW) consists primarily of
household garbage and other nonhazardous commercial,
institutional, and industrial solid waste. Municipal waste
combustor (MWC's) are used to reduce the mass and volume of MSW
that ultimately must be landfilled.
• ...
Currently, over 160 MWC plants are in operation in the U.S.
with capacities greater than 36 megagrams per day (Mg/d) [40 tons
per day (ton/d)]- and a total capacity of approximately ~ -
6-41
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100,000 Mg/day (110,000 ton/d) of MSW. It is predicted that by
1997, the total MWC capacity will approach 150,000 Mg/day
(165,000 ton/d), which represents over 28 percent of the
estimated total amount of MSW generated in the U.S. by the
year 2000.43 However, because permitting difficulties have
delayed construction of new units, these projections may be
optimistic. Table 6-17 shows the geographic distribution of MWC
units and capacities by States.43
In addition to these large units, a number of smaller,
specialized facilities around the U.S. also burn MSW. However,
the total nationwide capacity of those smaller units is only a
small fraction of the total capacity of units with individual
capacities of 36 Mg/d (40 ton/d) and larger.
6.5.1 Municipal Solid Waste Characteristics44'46
Municipal solid waste is a heterogeneous mixture of the
various materials found in household, commercial, and industrial
wastes. Major constituents in typical municipal waste are listed
in Table 6-18. Known sources of mercury in MSW are household and
film pack batteries, discarded electrical equipment and wiring,
fluorescent bulbs, paint residues, and plastics. As of 1989,
644 Mg (709 tons) of mercury were reported to be discarded in the
municipal solid waste stream, and the concentration of mercury in
solid waste is reported to be in the range of less than 1 to
6 ppm by weight with a typical value of 4 ppm by weight.45'46
However, because of changes in mercury consumption, these
concentrations are expected to decrease in the future.45'46
6.5.2 Process Description31'43/47
The three principal MWC classes are mass burn, refuse-
derived fuel (RDF), and modular combustors. The paragraphs below
briefly describe some of the key design and operating
characteristics of these different combustor types.
References 31, 43, and 47 provide more detailed process
6-42
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TABLE 6-17. SUMMARY OF GEOGRAPHICAL DISTRIBUTION OF MWC FACILITIES
State
AK
AL
AR
CA
CT
DC
DE
FL
GA
HI
IA
ID
IL
IN
MA
MD
ME
Ml
MN
MO
MS
MT
NC
NH
NJ
m. »* t
IMT
OH
OK
OR
PA
PR
SC
TN
TX
UT
VA
WA
Wl
Totals
Number of MWC
Facilities
2
2
5
3
9
1
1
14
1
1
1
1
1
1
10
3
4
5
13
1
1
1
4
4
6
15
4
2
3
6
1
2
4
4
1
9
5
_9_
160
State MWC Capacity
Mg/d (ton/d)
150(170)
900 (990)
350 (380)
2,330 (2,560)
6,050 (6,660)
910 (1,000)
550 (600)
15,770 (17,350)
450 (500)
2,510 (2,760)
1 80 (200)
45 (50)
1,450 (1,600)
2,150 (2,360)
9,400 (10,340)
3,460 (3,810)
1,700 (1,870)
4,380 (4,820)
4,850 (5,330)
71 (78)
140 (150)
65 (72)
710 (780)
780 (860)
5,290 (5,820)
11,370 (12,510)
4,360 (4,800)
1,120 (1,230)
740 (810)
6,550 (7,200)
950 (1,040)
760 (840)
1,350(1,480)
220 (240)
360 (400)
6,220 (6,840)
1,360 (1,500)
1.240 (1.360)
101,200 (111,400)
Percentage of Total
MWC Capacity in the
United States
<1
1
<1
2
6
1
<1
16
<1
2
<1
<1
1
2
9
3
2
4
5
<1
<1
<1
1
1
5
11
4
1
1
6
1
1
1
<1
<1
6
1
_L
100
Source: Reference 43.
6-43
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TABLE 6-18. CURRENT AND FORECAST COMPOSITION OF DISPOSED RESIDENTIAL
AND COMMERCIAL WASTE (WEIGHT PERCENT)
Component
Paper and Paperboard
Yard Wastes
Food Wastes
Glass
Metals
Plastics
Wood
Textiles
Rubber and Leather
Miscellaneous
Totals
Year
.1980
33.6
18.2
9.2
11.3
10.3
6.0
3.9
2.3
3.3
1.9
100.0
1990
38.3
17.0
7.7
8.8
9.4
8.3
3.7
2.2
2.5
2.1
100.0
Source: Reference 44.
6-44
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descriptions and process diagrams for each of the systems
described below.
In mass burn units, the MSW is combusted without any
preprocessing, other than removal of items too large to go
through the feed system. In a typical mass burn combustor,
refuse is fed onto a moving grate. Combustion air in excess of
stoichiometric amounts is supplied below (underfire air) and
above (overfire air) the grate. Mass burn combustors are usually
erected at the site (as opposed to being prefabricated at another
location) and range in size from 46 to 900 Mg/day (50 to
1,000 tons/d) of MSW throughput per unit. The mass burn
combustor category can be divided into mass burn refractory wall
(MB/REF), mass burn/waterwall (MB/WW), and mass burn/rotary
• . •
waterwall (MB/RC) designs. The two most common, MB/REF and
MB/WW, are described below.
The MB/REF combustors are older facilities that comprise
several designs. This type of combustor is continuously fed and
operates in an excess air mode with both underfire and overfire
air provided. The waste is moved on a traveling grate and is not
mixed as it advances through the combustor. As a result, waste
burnout or complete combustion is inhibited by fuel bed
thickness, and there is considerable potential for unburned waste
to be discharged into the bottom ash pit. Rocking and
reciprocating grate systems mix and aerate the waste bed as it
advances through the combustion chamber, thereby improving
contact between the waste and combustion air and increasing the
burnout of combustibles. The system generally discharges the ash
at the end of the grates to a water quench pit for collection and
disposal in a landfill. The MB/REF combustors have a
refractory-lined combustion chamber and operate at relatively
high excess air rates to prevent excessive temperatures, which
can result in refractory damage, slagging, fouling, and corrosion
problems.
6-45
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Because of their operating characteristics, the tracking
grate systems may have cool ash pockets in which mercury and
mercury compounds are not exposed to high temperature and are
thereby retained in the ash, rather than being exhausted with the
combustion gas stream. Consequently, mercury and mercury
compounds may be emitted as fugitive emissions from ash handling.
However, the combustion stack is the primary source of mercury
emissions. In the rocking and reciprocating grate systems,
essentially all mercury will be exhausted with the combustion
gas.
The MB/WW design represents the predominant technology in
the existing population of large MWC's, and it is expected that
over 50 percent of new units will be MB/WW designs. . In MB/WW
units, the combustor walls are constructed of metal tubes that
contain pressurized water and recover radiant energy from the
combustion chamber. With this type of system, unprocessed waste
(after removal of large, bulky items and noncombustibles) is
delivered by an overhead crane to a feed hopper that conveys the
waste into the combustion chamber. Nearly all modern MB/WW
facilities utilize reciprocating grates or roller grates to.move
the waste through the combustion chamber. The grates typically
include two or three separate sections where designated stages in
the combustion process occur. On the initial grate section,
referred to as the drying grate, the moisture content of the
waste is reduced prior to ignition. In the second grate section,
the burning grate, the majority of active burning takes place.
The third grate section, referred to as the burnout or finishing
grate, is where remaining combustibles in the waste are burned.
Bottom ash is discharged from the finishing grate into a water-
filled ash quench pit or ram discharger. From there, the moist
ash is discharged to a conveyor system and transported to an ash
loading area or storage area prior to disposal. Because the
waste bed is exposed to fairly uniform high combustion
temperatures, mercury and mercury compounds will be exhausted as
vapors with the combustion gases.
6-46
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Refuse-derived fuel combustors burn MSW that has been
processed to varying degrees; from simple removal of bulky and
noncombustible items accompanied by shredding, to extensive
processing to produce a finely divided fuel suitable for
co-firing in pulverized coal-fire boilers. Processing MSW to RDF
generally raises the heating value of the waste because many of
the noncombustible items are removed.
A set of standards for classifying RDF types has been
established by the American Society for Testing and Materials
(ASTM). The type of RDF used is dependent on the boiler design.
Boilers that are designed to burn RDF as the primary fuel usually
utilize spreader stokers and fire fluff RDF in a semi-suspension
mode. This mode of feeding is accomplished by using an air swept
distributor, which allows a portion of the feed to burn in
suspension and the remainder to be burned out after falling on a
horizontal traveling grate. The number of RDF distributors in a
single unit varies directly with unit capacity. The distributors
are normally adjustable so that the trajectory of the waste feed
can be varied. Because the traveling grate moves from the rear
to the front of the furnace, distributor settings are adjusted so
that most of the waste lands on the rear two-thirds of the grate
to allow more time for combustion to be completed on the grate.
Bottom ash drops into a water-filled quench chamber. Underfire
air is normally preheated and introduced beneath the grate by a
single plenum. Overfire air is injected through rows of high
pressure nozzles, providing a zone for mixing and completion of
the combustion process. Because essentially all of the waste is
exposed to high combustion temperatures, on the grate, most of the
mercury in the RDF will be discharged with the combustion gas
exhaust.
In a fluidized-bed combustor (FBC), fluff or pelletized RDF
is combusted in a turbulent bed of noncombustible material, such
as limestone, sand, or silica. In its simplest form, the FBC
consists of a combustor vessel equipped with a gas distribution
6-47
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plate and an underfire air windbox at the bottom. The combustion
bed overlies the gas distribution plate. The RDF may be injected
into or above the bed through ports in the combustor wall. The
combustor bed is suspended or "fluidized" through the
introduction of underfire air at a high pressure and flow rate.
Overfire air is used to complete the combustion process.
Good mixing is inherent in the FBC design. Fluidized-bed
combustors have uniform gas temperatures and mass compositions in
both the bed and in the upper region of the combustor. This
uniformity allows the FBC's to operate at lower excess air and
temperature levels than conventional combustion systems.
Waste-fired FBC's typically operate at excess air levels between
30 and 100 percent and at bed temperatures around 815°C (1500°F).
At this temperature, most mercury and mercury compounds will be
volatilized and exhausted with the combustion gas stream as a
vapor.
In terms of number of facilities, modular starved-
(or controlled-) air (MOD/SA) combustors represent a large
segment of the existing MWC population. However, because of
their small sizes, they account for only a small percentage of
the total capacity. The basic design of a MOD/SA combustor
consists of two separate combustion chambers, referred to as the
"primary" and "secondary" chambers. Waste is batch-fed
intermittently to the primary chamber by a hydraulically
activated ram. The charging bin is filled by a front-end loader
or by other mechanical systems. Waste is fed automatically on a
set frequency, with generally 6 to 10 minutes between charges.
Waste is moved through the primary combustion chamber by
either hydraulic transfer rams or reciprocating grates.
Combustors using transfer rams have individual"hearths upon which'
combustion takes place. Grate systems generally include two
separate grate sections. In either case, waste"retention times
6-48
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in the primary chamber are lengthy, lasting up to 12 hours.
Bottom ash is usually discharged to a wet quench pit.
The quantity of air introduced in the primary chamber
defines the rate at which waste burns. Combustion air is
introduced in the primary chamber at substoichiometric levels,
resulting in a flue gas rich in unburned hydrocarbons. The
combustion air flow rate to the primary chamber is controlled to
maintain an exhaust gas temperature set point [generally 650° to
980°C (1200° to 1800°F)], which corresponds to about 40 to
60 percent theoretical air. As the hot, fuel-rich flue gases
flow to the secondary chamber, they are mixed with excess air to
complete the burning process. Because the temperature of the
exhaust gases from the primary chamber is above the autoignition
point, completing combustion is simply a matter of introducing
air to the fuel-rich gases. The amount of air added to the
secondary chamber-is controlled to maintain a desired flue gas
exit temperature, typically 980° to 1200° (1800° to 2200°F). At
these primary chamber and secondary chamber temperatures,
essentially all of the mercury contained in the waste is expected
to be emitted as a vapor from the secondary chamber with the
combustion gas stream.
6.5.3 Emission Control Measures
Mercury emissions from MWC units are generally controlled by
adsorbing the mercury vapors from the combustion chamber onto the
acid gas sorbent material and then removing the particle-phase
mercury with a high-efficiency PM control device. The PM control
devices most frequently used in the U.S. are ESP's and fabric
filters. To achieve substantial mercury control, reducing flue
gas temperature at the inlet to the control device to
175°C (350°F) or less is beneficial.48 Typically, newer MWC
systems use a combination of gas cooling and duct sorbent
injection (DSI) or spray dryer (SD) systems upstream of the PM
device to reduce temperatures and provide a mechanism for acid
6-49
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gas control. The information contained in Reference 48 suggests
that these combined acid gas/PM systems can achieve improved
mercury control by injecting sodium sulfide (Na2S), activated
carbon, or modified activated carbon into the flue gas upstream
from the DSI or SD unit. The paragraphs below briefly describe
the DSI and SD processes. Because the ESP's and FF's used on
MWC's are comparable to those used on other combustion systems,
they are not described. References 43 and 48 provide more
detailed descriptions of the control systems and additional
information on the performance of these systems.
Spray drying in combination with either fabric filtration or
an ESP is the most frequently used acid gas control technology
for MWC's in the United States. Spray dryer/fabric filter
systems are more common than SD/ESP systems and are used most on
new, large MWC's. In the spray drying process, lime is slurried
and then injected into the SD through either rotary atomizer or
dual-fluid nozzles. The key design and operating parameters that
significantly affect SD acid gas performance are the SD's outlet
temperature and lime-to-acid gas stoichiometric ratio. The SD
outlet temperature, which affects mercury removal, is controlled
by the amount of water in the lime slurry.43
With DSI, powdered sorbent is pneumatically injected into
either a separate reaction vessel or a section of flue gas duct
located downstream of the combustor economizer. Alkali in the
sorbent (generally calcium) reacts with HC1 and S02 to form
alkali salts (e.g., calcium chloride [CaCl2] and calcium sulfite
[CaSO3]). Some units also use humidification or other
temperature control measures upstream from the collection device.
Reaction products, fly ash, and unreacted sorbent are collected
with either an ESP or fabric filter.43
• ••
Add-on mercury control techniques include the injection of
activated carbon or Na2S into the flue gas prior to the PM
control system. In sodium sulfide injection, an Na2S solution is
6-50
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sprayed into cooled flue gas (about 200°C [390°F]) prior to the
acid gas control device. The reaction of Na2S and Hg
precipitates solid mercuric sulfide (HgS) that can be collected
in the PM control device.43 These technologies have not been
used commercially on MWC's in the United States, but have been
applied to MWC's in Europe, Canada, and Japan, where removal
efficiencies have been reported to range from over 50 percent to
90 percent, but concerns have been raised that analytical
problems may have caused these efficiencies to be overstated.48
Recent test programs using activated carbon and Na2S
injection have been conducted in the United States. For
activated carbon injection, mercury removal efficiencies reported
generally range from 80 percent to over 95 percent. Other test
results show mercury reductions ranging from 50 to over
95 percent, depending on the carbon feed rate, with average
outlet Hg concentrations generally ranging from 30 to
200 /zg/dscm.43'48
6.5.4 Emissions
The primary source of mercury emissions from municipal waste
combustors is the combustion gas exhaust stack. However, small
amounts of mercury may be emitted as part of the fugitive PM
emissions from fly ash handling, particularly if highly efficient
dry control systems are used.
A recent study conducted to update the municipal waste
combustion section of AP-42 provided a comprehensive review of
the available MWC mercury emission data, which are summarized in
Table B-2 of Appendix B. The emission data that are presented in
Appendix B are in concentration units rather than emission
factors because the study found that most of the test reports
contained insufficient process data to generate emission factors.
6-51
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After reviewing the test data, the authors concluded that
the development of emission factors for MWC's, using only the
test reports which estimated feed rates, would eliminate data
from so many facilities, especially key facilities, that the
values derived were not likely to be representative of the entire
MWC population. In addition, the subjective nature of the refuse
feed rates called into question the validity of the limited data.
Consequently, emission factors were developed using the F-factor,
which is the ratio of the gas volume of the products of
combustion to the heating value of the fuel. This approach,
presented in EPA Method 19, requires an F-factor and an estimate
of the fuel heating value. For MWC's, the F-factor is
0.257 dscm/MJ (9,570 dscf/106 Btu) (at 0 percent 02). For all
combustor types, except RDF combustors, a heating value of
10,500 kJ/kg (4,500 Btu/lb) refuse was assumed. For RDF
combustor units, the processed refuse has a higher heating value,
and a heating value of 12,800 kJ/kg (5,500 Btu/lb) was assumed.
Overall, these data are representative of average values for
MWC's.43
The resultant best typical emission factors for different
combinations of combustor and control device are presented in
Table 6-19. While this procedure does provide good average
emission factors that represent an industry cross section, it
should not be used to convert individual data points in
Appendix B. The assumed F-factor and waste heating values above
may not be appropriate for specific facilities.
6.6 SEWAGE SLUDGE INCINERATORS
Currently about 200 sewage sludge incinerators (SSI's)
operate in the United States using one of three technologies:
multiple hearth, fluidized-bed, and electric infrared. Multiple
hearth units predominate, with over 80 percent of the identified,
operating SSI's being of that type. About 15 percent of the
SSI's are fluidized-bed combustors; 3 percent are electric :
6-52
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TABLE 6-19. BEST TYPICAL MERCURY EMISSION FACTORS
FOR MUNICIPAL WASTE COMBUSTORS
Cpmbustor type
Mass burn/waterwall
Mass burn/rotary
waterwall
Mass burn/refractory wall
Refuse-derived fuel-fired
Modular/excess air
Modular/starved air
Control status3
UN
SD or DSI/FF
SD/ESP
ESP
SD or DSI/FF
UN
ESP
DSI/ESP
UN
SD/FF
SD/ESP
ESP
ESP
UN
ESP
Typical mercury emission factors
g/Mg waste
2.8
1.1
1.6
2.8
1.1
2.8
2.8
2.0
2.8
1-4
0.21
2.8
2.8
2.8
2.8
10"^ Ib/ton waste
5.6
2.2
3.3
5.6
2.2
5.6
5.6
4.0
5.5
2.9
0.42
5.5
5.6
5.6
5.6
Source: Reference 43.
aUN = uncontrolled, SD = spray dryer, FF
DSI = duct sorbent injection.
= fabric filter, ESP = electrostatic precipitator,
6-53
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infrared; and the remainder cofire sewage, sludge with municipal
solid waste.49
Figure 6-1 shows the distribution of sewage sludge
incinerators in the United States50 Most facilities are located
in the Eastern United States, but a substantial number are also
located on the West Coast. New York has the largest number of
SSI facilities with 33, followed by Pennsylvania and Michigan
with 21 and 19, respectively. About 1.5 x 106 Mg
(1.6 x 106 tons) of sewage sludge on a dry basis are estimated to
be incinerated annually.49
Limited data obtained on the mercury content of sewage
sludge obtained in the mid 1970's indicated that mercury
concentrations in municipal sewage sludge range from 0.1 to
89 ppmwt with a mean value of 7 ppmwt and a median value of
4 ppmwt.14 Similar data collected by EPA from 42 municipal
sewage treatment plants in the early 1970's showed a range of 0.6
to 43 ppmwt, with a mean value of 4.9 ppmwt on a dry solids
basis.51 No more recent data were located during this study, and
no information is available on how changes in waste disposal and
waste treatment practices may affect these levels.
The sections below provide SSI process descriptions, a
discussion of control measures, and a summary of mercury emission
factors.
6.6.1 Process Description4^'49
Figure. 6-2 presents a simplified diagram of the sewage
sludge incineration process, which involves two primary steps.
The first step in the process of sewage sludge incineration is
the dewatering of the sludge. Sludge is generally dewatered
until it is about 15 to 30 percent solids. When it is more than
25 percent solids, the sludge will usually burn without auxiliary
fuel. After dewatering, the sludge is sent to the incinerator,
6-54
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HI-3
Rgure 6-1. Distribution of sewage sludge incinerators in the U.S.
6-55
50
-------
GAS EXHAUST
INDUCED
DRAFT PAN
FUGITIVE EMISSIONS
• POTENTIAL SOURCES OF MERCURY EMISSIONS
VENTURI WATER
Figure 6-2. Process flow diagram for sludge incineration.
. 6-56
-------
and thermal oxidation occurs. The unburned residual ash-is
removed from the incinerator, usually on a continuous basis, and
is disposed. A portion of the noncombustible waste, as well as
unburned volatile organic compounds, is carried out of the
combustor through entrainment in the exhaust gas stream. Air
pollution control devices, primarily wet scrubbers, are used to
remove7the entrained pollutants from the exhaust gas stream. The
gas stream is then exhausted, and the collected pollutants are
sent back to the head of the wastewater treatment plant in the
scrubber effluent. As shown in Figure 6-2, the primary source of
mercury emissions from the SSI process is the combustion stack.
Some fugitive emissions may be generated from ash handling, but
the quantities are expected to be small. Because mercury and
mercury compounds are relatively volatile, most mercury will
leave the combustion chamber in the exhaust gas; concentrations
in the ash residue are expected to be negligible.
The paragraphs below briefly describe the three primary SSI
processes used in the United States. .References 32 and 49
provide more detailed descriptions and process diagrams.
The basic multiple hearth furnace is cylindrical in shape
and is oriented vertically. The outer shell is constructed of
steel, lined with refractory, and surrounds a series of
horizontal refractory hearths. A hollow cast iron rotating shaft
runs through the center of the hearths. Attached to the central
shaft are the rabble arms with teeth shaped to rake the sludge in
a spiral motion, alternating in direction from the outside in,
then inside out, between hearths. Typically, the upper andx lower
hearths are fitted with four rabble arms, and the middle hearths
are fitted with two. Cooling air for the center shaft and rabble
arms is introduced into the shaft by a fan located at its base.
Burners that provide auxiliary heat are located in the sidewalls
of the hearths.
6-57
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Partially dewatered sludge is typically fed onto the
perimeter of the top hearth. Typically, the rabble arms move the
sludge through the incinerator as the motion of the rabble arms
rakes the sludge toward the center shaft, where it drops through
holes located at the center of the hearth. This process is
repeated in all of the subsequent hearths, with the sludge moving
in opposite directions in adjacent hearths. The effect of the
rabble motion is to break up solid material to allow better
surface contact with heat and oxygen.
Ambient air is first ducted through the central shaft and
its associated rabble arms. This air is then taken from the top
of the shaft and recirculated onto the lowermost hearth as
preheated combustion air. The combustion air flows upward
through the drop holes in the hearths, countercurrent to the flow
of the sludge, before being exhausted from the top hearth.
Multiple hearth furnaces can be divided into three zones.
The upper hearths comprise the drying zone where most of the
moisture in the sludge is evaporated. The temperature in the
drying zone is typically between 425° and 760°C (800° and
1400°F). Sludge combustion occurs in the middle hearths (second
zone) as the temperature is increased between 815° and 925°C
(1500° and 1700°F). When exposed to the temperatures in both
upper zones, most mercury will be volatilized and discharged as
vapor in the exhaust gas. The third zone, made up of the
lowermost hearth(s), is the cooling zone. In this zone, the ash
is cooled as its heat is transferred to the incoming combustion
air. . x
Fluidized-bed combustors (FBC's) are cylindrically shaped
and oriented vertically. The outer shell is constructed of steel
and is lined with refractory. Tuyeres (nozzles designed to
deliver blasts of air) are located at the base of the furnace
within a refractory-lined grid. A bed of sand rests upon the
grid. Partially dewatered sludge is fed into the bed of the
6-58
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furnace. Air injected through the tuyeres, at pressures from
20 to 35 kPa (3 to 5 psig), simultaneously fluidizes the bed of
hot sand and the incoming sludge. Temperatures of 725° to 825°C
(1350° to 1500°F), which are sufficient to vaporize most mercury
contained in the sludge, are maintained in the bed. As the
sludge burns, fine ash particles and mercury vapor are carried
out the top of the furnace with the exhaust gas.
An electric incinerator consists of a horizontally oriented,
insulated furnace. A woven wire belt conveyor extends the length
of the furnace, and infrared heating elements are located in the
roof above the conveyor belt. Combustion air is preheated by the
flue gases and is injected into the discharge end of the furnace.
Electric incinerators consist of a number of prefabricated
modules that are linked together to provide the necessary furnace
length. The dewatered sludge cake is conveyed into one end of
the incinerator. An internal roller mechanism levels the sludge
into a continuous layer approximately 2.5 centimeters (cm)
~[1 inch (in.)] thick across the width of the belt. The sludge is
sequentially dried and then burned as it moves beneath the
infrared heating elements. Ash is discharged into a hopper at
the opposite end of the furnace. The preheated combustion air
enters the furnace above the ash hopper and is further heated by
the outgoing ash. The direction of air flow is countercurrent to
the movement of the sludge along the conveyor.
6.6.2 Emission Control Measures14
Most SSI's are equipped with some type of wet scrubbing
system for PM control. Because these systems provide gas cooling
as well as PM removal, they can potentially provide some mercury
control. Limited data obtained on mercury removal efficiencies
are presented in the emission factor discussion. The paragraphs
below briefly describe the wet scrubbing systems typically used
on existing SSI's.
6-59
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Wet scrubber controls on SSI's range from low pressure drop
spray towers and wet cyclones to higher pressure drop venturi
scrubbers and venturi/impingement tray scrubber combinations.
The most widely used control device applied to a multiple hearth
incinerator is the impingement tray scrubber. Older units use
the tray scrubber alone while combination venturi/impingement
tray scrubbers are widely applied to newer multiple hearth
incinerators and to fluidized-bed incinerators. Most electric
incinerators and some fluidized-bed incinerators use venturi
scrubbers only.
In a typical combination venturi/impingement tray scrubber,
hot gas exits the incinerator and enters the precooling or quench
section of the scrubber. Spray nozzles in the quench section
cool the incoming gas, and the quenched gas then enters the
venturi section of the control device. Venturi water is usually
pumped into an inlet weir above the quencher.. The venturi water
enters the scrubber above the throat and floods the throat
completely. Most venturi sections come equipped with variable
throats to allow the pressure drop to be increased, thereby
increasing PM efficiency. At the base of the flooded elbow, the
gas stream passes through a connecting duct to the base of the
impingement tray tower. Gas velocity is further reduced upon
entry to the tower as the gas stream passes upward through the
perforated impingement trays. Water usually enters the trays
from, inlet ports on opposite sides and flows across the tray. As
gas passes through each perforation in the tray, it creates a jet
that bubbles up the water and further entrains solid particles.
At the top of the tower is a mist eliminator to reduce the
carryover of water droplets in the stack effluent gas.
6.6.3 Emissions . . • . .
The primary source of mercury emissions from sewage sludge
incineration is the combustion gas exhaust stack. However, small
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quantities of mercury also may be emitted with the fugitive PM
emissions generated from bottom and fly ash handling operations
As a part of EPA's development of the mercury NESHAP for
SSI's and subsequent review of that NESHAP and as a part of the
recent update of AP-42, data have been developed on mercury
emissions from SSI's. These .data are tabulated in Appendix B,
Table B-3 and summarized in Table 6-20.
TABLE 6-20. SUMMARY OF MERCURY EMISSION FACTORS
FOR SEWAGE SLUDGE INCINERATORS
Incinerator
type3
MH
MH
MH
FB
FB
Control
status0
UN
IS
VS/IS
SC
VS/IS
No. data
points
6
2
1
1
3
Mercury emission factors
g/Mg dry sludge
Range
0.54 - 4.6
0.35 - 9.0
-
— '
0.026 - 3.1
Mean
2.0
0.62
1.1
24
0.72
10"3 Ib/ton dry sludge
Range
1.1-9.2
0.70- 1.8
—
—
0.052 -6.2
Mean
4.0
1.2
2.1
48
1.6
Source: References 49 and 51.
aMH = multiple hearth, FB = fluidized-bed.
b|JN = uncontrolled, IS = impingement scrubber, VS = venturi scrubber, SC = spray chamber.
If the spray chamber on the fluidized-bed unit for which
data are given in Table 6-20 is assumed to provide essentially no
mercury control, then the uncontrolled emission factors for
fluidized-bed and multiple hearth units combined range from
0.54 to 24 g/Mg (1.1 x 10"3 to 48 x 10"3 Ib/ton). This range is
consistent with the range of concentrations of mercury in sewage
sludge presented earlier (0.1 to 43 ppmwt) for two studies.
Because the data on sludge concentrations represent a larger
number of facilities than do the test data in Table 6-20, a best
typical emission factor of 5.0 g/Mg dry solids (10 x 10"3 Ib/ton
dry solids) was.selected. This emission factor is based on a
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typical sludge concentration of 5.0 ppmwt and the assumption that
all mercury in the sludge is emitted from the incinerator.
Limited data presented in Reference 38 indicate that the
impingement scrubbers, venturi scrubbers, and venturi/impingement
scrubber combinations have efficiencies in the range of
68 to 96 percent. These ranges are consistent with the data
contained in Table 6-20. Consequently, the best typical
controlled emission factor was obtained by applying this range to
the uncontrolled emission factor reported earlier. The resultant
emission factor range is reported in Table 6-21.
TABLE 6-21. BEST TYPICAL MERCURY EMISSION FACTORS FOR
SEWAGE SLUDGE INCINERATORS
Control status
Uncontrolled
Venturi scrubber, impinger
scrubber, or combination
Typical mercury emission factors
g/Mg dry sludge
5.0
0.2-1.6
1 0"3 Ib/ton dry sludge
10
0.4 - 3.2
The emission factors in Table 6-21 should be used cautiously
in that available data suggest that both mercury concentrations
in sludge and control efficiencies vary widely. Because mercury
emissions from SSI's are regulated by a NESHAP, all SSI's are
required to report their compliance status and mercury emission
rate annually. Hence, the best source of emission data for an
individual facility is the annual compliance status report, which
is available through EPA's Compliance Data System.
6.7 MEDICAL WASTE INCINERATION
Medical waste includes infectious and noninfectious wastes
generated by a variety of facilities engaged in medical care,
veterinary care, or research activities such as hospitals,
clinics, doctors' and dentists' offices, nursing homes,
veterinary clinics and hospitals, medical laboratories, and
6-62
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medical and veterinary schools and research units. Medical waste
is defined by the U. S. EPA as "any solid waste which is
generated in the diagnosis, treatment, or immunization of human
beings or animals, in research pertaining thereto, or in the
production or testing of biologicals." A medical waste
incinerator (MWI) is any device that burns such medical waste.52
Recent estimates developed by EPA suggest that about
3.06 million Mg (3.36 million tons) of medical waste are produced
annually in the United States. Approximately 5,000 MWI's, which
are distributed geographically throughout the United States, are
used to treat this waste. Of these 5,000 units, about 3,000 are
located at hospitals; about 150 are larger commercial facilities;
and the remainder are distributed among veterinary facilities,
nursing homes, laboratories, and other miscellaneous
facilities.53
Available information indicates that these MWI systems can
be significant sources of mercury emissions. Mercury emissions
result from mercury-bearing materials contained in the waste.
Although concentrations of specific metals in the waste have not
been fully characterized, known mercury sources include
batteries; fluorescent lamps; high-intensity discharge lamps
(mercury vapor, metal halide, and high-pressure sodium);
thermometers; special paper and film coatings; and pigments.
Batteries, primarily alkaline and mercury-zinc batteries, are a
major mercury source. Mercury is used in alkaline batteries,
which are used in digital thermometers, but this use is
declining. Mercury-zinc batteries are used in transistorized
equipment, hearing aids, watches, calculators, computers, smoke
detectors, tape recorders, regulated power supplies, radiation
detection meters, scientific equipment, pagers, oxygen and metal
monitors, and portable electrocardiogram monitors. '-'"'•
Cadmium-mercury pigments are primarily used in plastics but are
also used in paints, enamels, printing inks, rubber, paper, and
painted textiles.45'54 All of these materials can be routed to
6-63
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an MWI, thereby contributing to mercury emissions from this
source category.
6.7.1 Process Description
Although the ultimate destination of almost all medical
waste produced in the United States is a solid waste landfill,
the waste generally must be treated before it can be landfilled.
The primary functions of MWI facilities are to render the waste
biologically innocuous and to reduce the volume and mass of
solids that must be landfilled by combusting the organic material
contained in the waste. Over the years, a wide variety of MWI
system designs and operating practices have been used to
accomplish these functions. To account for these system
differences, a number of MWI classification schemes have been
used in past studies', including classification by waste type
(pathological, mixed medical waste, red bag waste, etc.),
classification by operating mode (continuous, intermittent,
batch), and classification by combustor design (retort,
fixed-hearth, pulsed-hearth, rotary kiln, etc.). Some insight
into MWI processes, emissions, and emissions control is provided
by each of these schemes. However, because the available
evidence suggests that mercury emissions are affected primarily
by waste characteristics, the characterization and control of
mercury emissions from MWI's can be discussed without considering
other MWI design and operating practices in detail. The
paragraphs below provide a generic MWI process description and
identify potential sources of mercury emissions. More detailed
Descriptions of specific MWI design and operating practices can
be found in References 55 through 57.
A schematic of a generic MWI system that identifies the
major components of the system is shown in Figure 6-3. "As
indicated in the schematic, most MWI's are multiple-chamber
combustion systems that comprise primary, secondary, and Ipossibly
tertiary chambers. The primary components of the MWI process are
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TO
ATMOSPHERE
a\
i
at
ui
CONTROL AND
MONrroRwa
TO
ATMOSPHERE
A •
POTENTIAL MERCURY EMISSION SOURCE
j STACK
STACK
WASTE l
HEAT '
BOILER
AIR i
POLLUTION '
CONTROL ?•
SYSTEM !
ASH
Figure 6-3. Major components of an incineration system.
-------
the waste-charging system, the primary chamber, the ash handling
system, the secondary chamber, and the air pollution control-
system, which are discussed briefly below.
Medical waste is introduced to the primary chamber via the
waste-charging system. The waste can be charged either manually
or mechanically. With manual charging, which is used only on
batch and smaller (generally older) intermittent units, the
operator opens a charge door on the side of the primary chamber
and tosses bags or boxes of waste into the unit. When mechanical
feed systems are employed, some type of mechanical device is used
to charge the waste to the incinerator. The most common
mechanical feed system is the hopper/ram assembly. In a
mechanical hopper/ram feed system, the following steps take
place: (1) waste is placed into a charging hopper manually, and
the hopper cover is closed; (2) a fire door isolating the hopper
from the incinerator opens; (3) the ram moves forward to push the
waste into the incinerator; (4) the ram reverses to a location
behind the fire door; (5) after the fire door closes, a water
spray cools the ram, and the ram retracts to the starting
position; and (6) the system is ready to accept another charge.
The entire hopper/ram charging sequence normally functions as a
controlled, automatically-timed sequence to eliminate
overcharging. The sequence can be activated by the operator or
for larger, fully automated incinerators, it may be activated at
preset intervals by an automatic timer.56,57
The potential for mercury emissions from the waste-charging
systems is .low. Mechanical systems are generally operated with a
double-door system to minimize fugitive emissions. Small
quantities of fugitive emissions may be generated while the
chamber door is open during manual charging, but no data are
available on the magnitude of these emissions.
The primary chamber (sometimes called the "ignition"
chamber) accepts the waste and begins the combustion process.
6-66
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Most modern MWI's operate this chamber in a "controlled-air" mode
to maintain combustion air levels at or below stoichiometric
requirements. The objectives of this controlled-air operation
are to provide a more uniform release of volatile organic
materials to the secondary chamber and to minimize entrainment of
solids in these off-gases. Three processes occur in the primary
chamber. First, the moisture in the waste is volatilized.
Second, the volatile fraction of the waste is vaporized, and the
volatile gases are directed to the secondary chamber. Third, the
fixed carbon remaining in the waste is combusted.
The primary chamber generates two exhaust streams--the
combustion gases that pass to the secondary chamber and the solid
ash stream that is discharged. Any metal compounds in the waste,
including mercury, are partitioned to these two streams in one of
three ways. The metals may be retained in the primary chamber
bottom ash and discharged as solid waste; they may be entrained
as PM in the combustion gases; or they may be volatilized and
discharged as a vapor with the combustion gases. Because mercury
and mercury compounds are generally quite volatile and because
the primary chamber typically operates in the range of 650° to
820°C (1200° to 1500°F), most of the mercury in the waste stream
will be exhausted as a vapor to the secondary chamber.
The primary chamber bottom ash, which may contain small
amounts of mercury or mercury compounds, is discharged via an ash
removal system and transported to a landfill for disposal. The
ash removal system may be either manual or mechanical.
Typically, batch units and smaller intermittent units employ
manual ash removal. After the system has shut down and the ash
has cooled, the operator uses a rake or shovel to remove the ash
and place it in a drum or dumpster. Some intermittent-duty MWI's
and all continuously operated MWI's use a mechanical ash removal
system. The mechanical system includes three major components:
(Da means of moving the ash to the end of the incinerator
hearth--usually an ash transfer ram or series of transfer rams,
6-67
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(2) a collection device or container for the ash as it iis
discharged from the hearth, and (3) a transfer system to move the
ash from the collection point. Generally, these automatic
systems are designed to minimize fugitive emissions. For
example, one type of collection system uses an ash bin sealed
directly to the discharge chute or positioned within an air-
sealed chamber below the hearth. A door or gate that seals the
chute is opened at regular intervals to allow the ash to drop
into the collection bin. When the bin is filled, the seal-gate
is closed, and the bin is removed and replaced with an empty bin.
In another system, the ash is discharged into a water pit. The
ash discharge chute is extended into the water pit so that an air
seal is maintained. The water bath quenches the ash as the ash
is collected. A mechanical device, either a rake or drag
conveyor system, is used to intermittently or continuously remove
the ash from the quench pit. The excess water is allowed to
drain from the ash as it is removed from the pit, and the wetted
ash is discharged into a collection container.
The potential for mercury emissions from both mechanical and
manual ash discharge systems is minimal. As described above,
most mechanical systems have seals and provide ash wetting as
described above to minimize fugitive PM emissions. While manual
systems can generate substantial fugitive PM, the concentrations
of mercury have generally been shown to be quite low.58
Consequently, fugitive mercury emissions are negligible.
Almost all the mercury that enters the primary chamber is
exhausted to the secondary chamber as a vapor. The primary
function of the secondary chamber is to complete the combustion
of the volatile organic compounds that was initiated in the
primary chamber. Because the temperatures in the secondary
chamber are typically 980°C (1800°F) or greater, essentially all
of the mercury that enters the secondary chamber will be
exhausted as a vapor. The hot exhaust gases"from the secondary
chamber may pass through an energy recovery device (waste heat
6-68
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boiler or air-to-air heat exchanger) and an air pollution control
system before they are discharged to the atmosphere through the
combustion stack. This combustion stack is the major route of
mercury emissions from MWI's.
6.7.2 Emission Control Measures
A number of air pollution control system configurations have
been used to control PM and gaseous emissions from the MWI
combustion stacks. Most of these configurations fall within the
general classes of wet systems and dry systems. Wet systems
typically comprise a wet scrubber designed for PM control
(venturi scrubber or rotary atomizing scrubber) in series with a
packed-bed scrubber for acid gas removal and a high-efficiency
mist elimination system. Most dry systems use a fabric filter
for PM removal, but ESP's have been installed on some larger
MWI's. These dry systems may use sorbent injection via either
dry injection or spray dryers upstream from the PM device to
enhance acid gas control. Because these systems are designed
primarily for PM and acid gas control, they have limitations
relative to mercury control. However, recent EPA studies
indicate that sorbent injection/fabric filtration systems can
achieve improved mercury control by adding activated carbon to
the sorbent material. More detailed descriptions of MWI air
pollution control systems can be found in Reference 58. The
emission data presented in the section below provide information
on the performance of some of the more common systems.
6.7.3 Emissions59'72
The primary source of emissions from medical waste
incineration is the combustion gas exhaust stack. However, small
quantities of mercury may be contained in the fugitive PM
emissions from ash handling operations, particularly if the fly
ash-is collected in a dry air pollution control system with high
mercury removal efficiencies.
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Over the past 5 years, mercury emissions have been measured
at several MWI's through the U. S. EPA's regulatory development
program, MWI emission characterization studies conducted by the
State of California, and compliance tests conducted in response
to State air toxic requirements. Emission data from
approximately 20 MWI's were identified in developing this L&E
document. However, only the data from 14 facilities were
considered adequate for emission factor development. For the
other facilities, either process data were insufficient to
develop emission factors or the test methodologies were
considered unacceptable. Emission data for the 14 facilities are
tabulated in Appendix B, Table B-4. The paragraphs below
summarize the information on uncontrolled emissions and on the
performance of emission control systems collected from these
14 facilities.
The uncontrolled emission data collected at eight facilities
show wide variability, with mercury emission factors ranging from
0.043 to 317 g/Mg of waste charged (8.6 x 10"4 to
6.3 x 10-1 Ib/ton). These data represent a variety of waste
types (mixed medical waste, red bag [infectious] waste only, and
pathological waste) and incinerator types (continuous and
intermittent units with varied operating practices). While the
data are insufficient to demonstrate a direct relationship
between waste characteristics and emissions, the data strongly
suggest that most of this variability is related to differences
in the mercury content of the waste. First, characterization of
the bottom ash at several facilities showed virtually no mercury
in the ash, indicating that the mercury in the waste is
discharged with the combustion gases. Second, as part of an EPA
study, wastes from two different hospitals were fired to the same
incinerator under comparable operating conditions. The average
emission factors for the two wastes varied by over an order of
magnitude with wastes from the smaller hospital yielding an
emission factor of 1 g/Mg (2.2 x 10"3 Ib/ton) and those from the
larger hospital yielding a factor of 66 g/Mg (1.3 x 10"x Ib/ton),
6-70
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again providing evidence of substantial waste-related variation.
Although there has been some speculation that the higher emission
factors result from having mercury-bearing items, such as
batteries and disposable thermometers in the waste stream,
insufficient information is available to define conclusively the
influence of waste attributes on mercury emissions.
Because emissions are strongly related to waste
characteristics, separate uncontrolled emission factors were
developed for the different waste types. These emission factors
are summarized in Table 6-22. Substantially greater information
is available for mixed medical waste incineration than for either
red bag or pathological waste incineration. Consequently, the
mixed waste' results are considered to be a more reliable
indicator of the range of emission factors likely to be found
across the MWI population than are the red bag or pathological
results. However, because the range in emission factors is so
large, even the mixed waste emission factors should be applied to
individual MWI's with caution. In particular, the average
emission factor of 50 g/Mg (1.1 x 10"^ Ib/ton) is strongly
influenced by the largest emission factor identified
(317 g/Mg [6.3 x 10"1 Ib/ton]), which is a factor of 5 larger
than the second largest value. If the largest and smallest
values are removed, the trimmed mean is 20 g/Mg
(4.0 x 10"2 Ib/ton), which is of the same order of magnitude as
the median of the data. Hence, the emission factor of 20 g/Mg
(4.0 x 10~2 Ib/ton) is recommended as the best emission factor
for a typical MWI firing mixed medical waste.
The emission factors for the red bag and pathological waste
should be used with extreme caution because each factor is based
on results from waste fired at only one facility. Two
observations are noteworthy in interpreting these data. First,
the red bag emission factor of 16 g/Mg (3.2 x 10"2 Ib/ton) is at
the upper end of the range of emission factors. However, the
wastes were generated by the same facility that had.the largest
6-71
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TABLE 6-22. SUMMARY OF UNCONTROLLED MERCURY EMISSION FACTORS
FOR MEDICAL WASTE INCINERATORS
Waste type
Mixeda-b
Red bag
Pathological
No. of
facilities
9
1
1
No. of
test runs
54
10
6
Mercury emission factors,
g/Mg CIO"3 Ib/ton) waste
Range
0.043 -317
(0.086 - 634)
1 0 - 27C
(20 - 54)
d
Mean
50.4
(101)
16
(32)
0.5
(1.0)
Source: References 59-67 and 70.
aBased on the range of facility averages. Number of runs for each facility ranged from two to nine.
'•'This emission factor is strongly influenced by a single large value. A better estimate of emissions
from a "typical" facility is the trimmed mean, which is 20 g/Mg (40 x 10"^ Ib/ton).
c Based on the range spanned by three test averages (two tests comprised three runs; one test
comprised four runs) at one facility.
two tests (three runs each) resulted in the same emission factor. - A range could not be
determined.
6-72
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mixed waste emission factor, so the high factor may be
misleading. Similarly, the emission factor for pathological
waste of 0.5 g/Mg (1.0 x 10"3 Ib/ton) is at the bottom end of the
mixed waste range. However, this low emission factor also may be
misleading because tests at the same facility produced the lowest
mixed waste emission factor. As evidenced by these observations,
the red bag and pathological emission data are too sparse to
differentiate between the effects of waste type and
facility-specific waste practices on mercury emissions.
Substantially fewer data are available on controlled
emissions than on uncontrolled emissions. lf°2/°°~72 The best
data available are those generated by the U. S. EPA to
characterize the performance of three MWI air pollution control
systems--a venturi scrubber/packed-bed system, a dry
injection/fabric filter system, and a spray dryer/fabric filter
system. Table 6-23 presents controlled emission factors, mercury
emission control efficiencies, and flue gas temperatures for
these air pollution control systems. Because controlled emission
factors could only be developed for a few facilities, they are
not likely to represent the variability across the incinerator
population, Theiref ore,- it is recommended, that controlled
emission factors be developed by applying the average control
efficiencies to uncontrolled emission factors or emission rates
rather than using the controlled emission factors presented in
Table 6-23.
The performances of the dry systems were examined with and
without carbon injection. The results from these tests are also
presented in Table B-4, Appendix B. These results indicate that
the two dry systems without carbon injection provided essentially
no control of mercury. For these systems, the outlet mercury
emissions range from 400 percent higher to 40 percent lower than
the inlet emissions, depending on the flue gas temperature. This
variability is considered to be within the normal range of
process and emission test method variability as described in
6-73
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TABLE 6-23. SUMMARY OF CONTROLLED MERCURY EMISSION FACTORS AND CONTROL
EFFICIENCIES FOR MEDICAL WASTE INCINERATORS
Waste
type8
M
RB
Control
8tatU8b
VS/PB
DI/ESP
DI/FF
DI/FF + C
SD/FF
SD/FF + C
DI/FF
No. of
facilities.
4
1
No. of
runs
11
3
9
5
3
3
9
Mercury emission factors0
g/Mg waste
Mean
5.4
9.0
50
4.2
24
4.0
26
Range
0.72-20
2.7-17
20-110
0.74-6.4
8.3 49
1.5-6.1
2.6-84
10'31b/ton waste
Mean
11
18
100
8.3
48
8.0
52
Range
1.4-40
5.533
1 7-220
1.5-13
17-98
3.0-12
5.2-170
Control efficiency, %d
Mean
8.0
NA
20
91
38
90
-76
Range
-52-62°
NA
-18-70
85-98
25-51
84-96
-400-45
Flue gas temp. °F
Mean
186
402
299
291
285
282
314
Range
120-301
309-405
289-307
282-296
—
270-289
305-321
a\
i
-j
Source: References 61, 62, and 66-72.
aM = mixed medical waste, RB = red bag waste.
VS - venturi scrubber, PB = packed bed scrubber, 01 = dry injection
ESP = electrostatic precipitator, FF = fabric filter, C = carbon injection, SO = spray dryer.
cRanges are for individual runs. Averages were obtained by taking the arithmetic mean of facility averages.
dNA = not available.
Efficiency data were available for only one facility.
-------
Section 9. Consequently, the results are consistent with-no
measured removal by the control system. However, the dry systems
with carbon injection can achieve mercury removal efficiencies in
the range of 90 to 95 percent.
The emission test-results for the wet systems are also
presented in Table B-4, Appendix B. As shown in Table 6-23, the
performance of the wet systems in controlling mercury emissions
was comparable to that achieved by the dry system without carbon
injection. Similar to dry systems, the performance of the wet
systems is directly related to flue gas temperature. It is also
dependent on the blowdown rate, with efficiency falling if the
system approaches equilibrium. The only control systems that
provided any degree of control of mercury emissions were the dry
systems with carbon injection. Table 6-24 presents the best
typical uncontrolled emission factors for MWI's. To obtain best
typical controlled emission factors for systems with controls
other than dry injection with carbon addition, use these emission
factors. For dry systems with carbon injection, apply a
90-percent efficiency to these uncontrolled emission factors.
TABLE 6-24. bfcbl lYPiuAL UNCONTROLLED MERCURY EMISSION FACTORS
FOR MEDICAL WASTE INCINERATORS
Waste type
Mixed
Red Bag
Pathological
Typical mercury emission factors
g/Mg waste
20
16
0.5
1 0"3 Ib/ton waste
40
32
1
6-75
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SECTION 7
EMISSIONS FROM MISCELLANEOUS SOURCES
Mercury has been found to be emitted from various
miscellaneous sources including the following:
1. Portland cement manufacturing,
2. Lime manufacturing,
3. Carbon black production,
4. Byproduct coke production,
5. Primary lead smelting,
6. Primary copper smelting,
7. Petroleum refining,
8. Oil shale retorting, and
9. Geothermal power plants.
Raw materials processed at the facilities listed above
include minerals, ores, and crudes extracted from the earth. ,
Many of these raw materials contain mercury. At various stages
of processing, the raw materials are heated. Therefore, each of
the manufacturing processes listed above may emit mercury during
various steps of raw materials processing. This section presents
process information, air pollution control measures, and
estimates of mercury emissions for these sources.
*
7.1 PORTLAND CEMENT MANUFACTURING73"76
More than 30 raw materials are used to manufacture portland
cement. These materials can be classified into four basic
classes of raw materials: calcarious, siliceous, argillaceous,
and ferriferous. Two processes, the wet and dry processes, can
be used to manufacture portland cement. In 1990, there were a
. •
total of 212 U.S. cement kilns with a combined total clinker
capacity of 73.5 x 106 Mg (81.1 x 10s tons). Of this total, 11
kilns with a combined capacity of 1.8' x 106 Mg (2.0 x 106 tons)
7-1
-------
were inactive. The total number of active kilns was 201 with a
clinker capacity of 71.8 x 106 Mg (79.1 x 106 tons). The name,
location, and clinker capacity of each kiln is presented in
Appendix C. Based on 1990 U.S. cement kiln capacity data, an
estimated 68 percent of the portland cement is manufactured using
the dry process, and the remaining 32 percent based on the wet
process. A description of the processes used to manufacture
portland cement and the emissions resulting from the various
operations is presented below.
7.1.1 Process Description
Figure 7-1 presents a basic flow diagram of the portland
cement manufacturing process. The process can be divided into
four major steps: raw material acquisition and handling, kiln
feed preparation, pyroprocessing, and finished cement grinding.
The initial step in the production of portland cement
manufacturing is raw materials acquisition. Calcium,' which is
the element of highest concentration in portland cement, is
obtained from a variety of calcareous raw materials, including
limestone, chalk, marl, sea shells, aragonite, and an impure
limestone known as "natural cement rock." The other raw
materials--silicon, aluminum, and iron--are obtained from ores
and minerals, such as sand, shale, clay, and iron ore. Mercury
is expected to be present in the ores and minerals extracted from
the earth. The only potential source of mercury emissions from
raw material acquisition would be due to wind blown mercury-
containing particulate from the quarry operations. Mercury
emissions are expected to be negligible from these initial steps
in portland cement production.
The second step involves preparation of the raw materials
for pyroprocessing. Raw material preparation includes a variety
of blending and sizing operations designed to.provide a feed .with
appropriate chemical and physical properties. The raw material
7-2
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DRY PROCESS
OPTIONAL r
PREHEATEH/
PRECALCINER
OPTIONAL
PREHEATER
A PM.
PRODUCTS
OF FUEL
COMBUSTION
,PM
GYPSUM
I
U)
WATER
WET PROCESS
Figure 7-1. Process flow diagram of portland cement manufacturing process.
-------
processing differs somewhat for wet- and dry-process. At
facilities where the dry process is used, the moisture content in
the raw material, which can range from less than 1 percent to
greater than 50 percent, is reduced to less than 1 percent.
Mercury emissions can occur during this drying process but are
anticipated to be very low because the drying temperature is much
below the boiling point of mercury. At some facilities, heat for
drying is provided by the exhaust gases from the pyroprocessor.
At facilities where the wet process is used, water is added to
the raw material during the grinding step, thereby producing a
pumpable slurry containing approximately 65 percent solids.
Pyroprocessing (thermal treatment) of the raw material is
carried out in the kiln, which is the heart of the portland
cement manufacturing process. During pyroprocessing, the raw
material is transformed into clinkers, which are gray, glass-
hard, spherically-shaped nodules that range from 0.32 to 5.1 cm
(0.125 to 2.0 in.) in diameter. The chemical reactions and
physical processes that take place during pyroprocessing'include:
1. Evaporation of uncombined water from raw materials as
material temperature increases to 100°C (212°F),
2. Dehydration as the material temperature increases from
100°C to approximately 430°C (800°F) to form the oxides of
silicon, aluminum, and iron,
3. Calcination, during which carbon dioxide (C02) is
evolved, between 900°C (1650'F) and 982°C (1800°F) to form
calcium oxide,
4. Reaction of the oxides in the burning zone of the rotary
kiln to form cement clinker at temperatures about 1510°C
(2750°F).
7-4
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The rotary kiln is a long, cylindrical, slightly inclined,
refractory-lined furnace. The raw material mix is introduced
into the kiln at the elevated end, and the combustion fuels are
usually introduced into the kiln at the lower end, in a
countercurrent manner. The rotary motion of the kiln transports
the raw material from the elevated end to the lower end. Fuel
such as coal or natural gas, or occasional^ oil, is used to
provide energy for calcination. Mercury is present in coal and
oil. Tables 6-4 and 6-11 presented data pertaining to mercury
content in coal and oil, respectively. ' Use of other fuels, such
as chipped rubber, petroleum coke, and waste solvents, is
becoming increasingly popular. Combustion of fuel during the
pyroprocessing step contributes to potential mercury emissions.
Mercury may also be present in the waste-derived fuel mentioned
above. Because mercury evaporates at approximately 350°C
(660°F) , most of the mercury present in the raw materials can be
expected to be volatilized during the pyroprocessing step. Since
temperature at the inlet to the air pollution control device
generally do not exceed this temperature, at least a portion of
the condensed mercury should be captured with the particulate
emissions.
Pyroprocessing can be carried out using one of five
different processes: wet process, semi-dry, dry process, dry
process with a preheater, and dry process with a
preheater/precalciner. These processes essentially accomplish
the same physical and chemical steps described above. The last
step in the pyroprocessing is the cooling of the clinker. This
process step recoups up to 30 percent of the heat input to the
kiln system, locks in desirable product qualities by freezing
mineralogy, and makes it possible to handle the cooled clinker
with conventional conveying equipment. Finally, after the cement
clinker is cooled, a sequence of blending arid grinding operations
is carried out to transform the clinker into finished portland
cement.
7-5
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7.1.2 Emission Control Measures
With the exception of the pyroprocessing operations, the
emission sources in the portland cement industry can be
classified as either process emissions or fugitive emissions.
The primary pollutants resulting from these fugitive sources are
PM. The control measures used for ^:hese fugitive dust sources
are comparable to those used throughout the mineral products
industries.
Methods used to reduce particulate levels in the ambient air
due to vehicular traffic include paving and road wetting.
Additional methods that are applied to other open dust sources
include water sprays with and without surfactants, chemical dust
suppressants, wind, screens, and process modifications to reduce
drop heights or enclose storage operations.
Process fugitive emission sources include materials handling
and transfer, raw milling operations in dry process facilities,
and finish milling operations. Potential mercury emission
sources are indicated in Figure 7-1 by solid circles. Typically,
particulate emissions from these processes are captured by a
ventilation system with a fabric filters. Because the dust from
these units is returned to the process, they are considered to be
process units as well as air pollution control devices. The
industry uses shaker, reverse air, and pulse jet filters, as well
as some cartridge units, but most newer facilities use pulse jet
filters. For process fugitive operations, the different systems
are reported to achieve typical outlet PM loadings of
45 milligrams per cubic meter mg/m3 (0.02 grains per actual cubic
foot [gr/acf]). Because the mercury is in particle form, the
performance of these systems relative to mercury control is
expected to be equivalent to this overall particulate
performance. However, no data are available on mercury
performance of fugitive control measures.
7-6
-------
In the pyroprocessing units, PM emissions are controlled by
fabric filters (reverse air, pulse jet, or pulse plenum) and
ESP's. The reverse air fabric filters and ESP's typically used
to control kiln exhausts are reported to achieve outlet PM
loadings of 45 mg/m3 (0.02 gr/acf). Clinker cooler systems are
controlled most frequently with pulse jet or pulse plenum fabric
filters. A few gravel bed (GB) filters have been used on clinker
coolers.
According to MacMann, limited data indicate that ESP's
capture about 25 percent and baghouses capture up to 50 percent
of the potential mercury emissions as particulate.77 If this
cement kiln dust (CKD) is returned to the process, the mercury or
mercury compounds in the dust are volatilized again and therefore
essentially all of the mercury input to the process eventually
leaves as a vapor in the kiln stack. If the dust is wasted,
25 to 50 percent of the mercury input to the process escapes as a
solid in the CKD with the remaining 50 to 75 percent escaping as
* 77
a vapor in the kiln stack. '' Some levels of mercury have been
detected in the portland cement product.7°
7.1.3 Emissions
The principal sources of mercury emissions are expected to
be from the kiln and preheating/precalcining steps. Negligible
quantities of emissions would be expected in the raw material
processing and mixing steps because the only source of mercury
would be fugitive dust containing naturally occurring quantities
of mercury compounds in the limestone. Processing steps that
occur after the calcining process in the kiln would be expected
to be a much smaller source of emissions than the kiln.
Potential mercury emission sources are denoted by solid circles
in Figure 7-1. Emissions resulting from all processing steps
include particulate matter. Additionally, emissions from the
pyroprocessing step include other products of fuel combustion
such as sulfur dioxide (S02), nitrogen oxides (NOX), carbon
7-7
-------
dioxide (C02)/ and carbon monoxide (CO). Carbon dioxide from the
calcination of limestone will also be present in the flue gas.
Cement kiln test reports were reviewed for facilities
performing Certification of Compliance (COO tests required of
all kilns burning waste derived fuel (WDF). Fifteen of the test
reports contained sufficient process information to allow
calculation of mercury emission factors for the kiln stack; these
data are shown in Appendix C, Table C-2. The results from these
15 kilns showed a range in average emission factors from
2.23 x 1CT3 g/Mg of clinker (4.5 x 10~6 Ib/ton of clinker) to
0.49 g/Mg of clinker (9.7 x 10"4 Ib/ton of clinker). The average
emission factor for all 15 facilities was 8.7 x 10"2 g/Mg of
clinker (1.7 x 10"4 Ib/ton of clinker). These data are based on
the average of all test runs.
7.2 LIME MANUFACTURING
Lime is produced in various forms, with the bulk of
production yielding either hydrated lime or quicklime. In 1992,
producers sold or used 16.4 x 10^ Mg (18 x 10^ tons) of lime
produced at 113 plants in 32 States and Puerto Rico. The 1992
production represented a 4 percent increase over 1991 production.
In 1989, there were 116 lime production operations in the U.S.
with a annual production of 15.56 x 106 Mg (17.15 x 106 tons).78
The leading domestic uses for lime include steelmaking, flue gas
desulfurization, pulp and paper manufacturing, water
purification, and soil stabilization.78
Appendix C provides a list of the active lime plants in the
United States in 1991. The list includes company headquarters'
locations, plant locations by State, and the type of lime
produced at each plant. The geographical locations by State of
the lime operations are shown in Table 7-1.
7-8
-------
TABLE 7-1. LIME PRODUCERS IN THE UNITED STATES IN 1989
State
Alabama
Arizona
Arkansas, Louisiana, Oklahoma
California
Colorado, Nevada, Wyoming
Hawaii, Oregon, Washington
Idaho
Illinois, Indiana, Missouri
Iowa, Nebraska, South Dakota
Kentucky, Tennessee, West Virginia
Massachusetts
No. of
Plants
5
3
3a
11
9a
4a
3
8a
4a
5a
2
State
Michigan
Minnesota,
Montana
North Dakota
Ohio
Pennsylvania
Texas
Utah
Virginia
Wisconsin
Puerto Rico
No. of
Plants
8
7a
3
9
10
8
4
5
4
1
Source: Reference 78.
aTotal for States listed.
7-9
-------
7.2.1 Process Description .
Lime is produced by calcining (removal of C02) limestone at
a high temperature. The product of the calcining operation is
quicklime; this material can be hydrated with water to produce
hydrated lime or slaked lime (Ca(OH)2). -Figure 7-2 presents a
flow diagram for the lime manufacturing process. Lime
manufacturing is carried out in five major steps. These are:
1. Quarrying raw limestone,
2. Preparing the limestone for calcination,
3. Calcining the limestone,
4.. Processing the lime by hydrating, and
5. Miscellaneous transfer, storage, and handling
processes.
The manufacturing steps in lime production are very similar
to that of the dry portland cement process, which was discussed
in the previous section. The most important process step with
respect to emissions of mercury and other air pollutants is the
calcination. During calcination, kiln temperature may reach
1820°C (3300°F). Approximately 90 percent of the lime produced
in the United States is manufactured by calcining limestone in a
rotary kiln. Other types of lime kilns include the vertical or
shaft kiln, rotary hearth, and fluidized bed kilns. Fuel, such
as coal, oil, petroleum coke, or natural gas, may be used to
provide energy for calcination. Petroleum coke is usually used
in combination with coal. Auxiliary fuels such as chipped rubber
and waste solvents may potentially be used; at the present time,
however, no lime kilns use these auxiliary fuels.
Mercury is expected to be present in very small quantities
in the limestone and in coal and oil used as- fuel. Tables 6-4
and 6-11 present data pertaining to the mercury content in coal
and oil, respectively. The predominant fuel sources for lime
kilns are coal, coal/petroleum coke, and natural gas; oil is
rarely used as a fuel source. As with the production of portland
cement, any mercury present in the raw materials can be expected
7-10
-------
! I
§ i
ill
ITOM
RAWMATBMKTOKMi
h
MAX. MB OJf* . U ••
WATW
Figure 7-2. Process flow diagram for lime manufacturing
process. ^
7-11
-------
to be emitted in the lime kiln. Combustion of fuel in the lime
kiln is the major.contributor to mercury emissions. :
7.2.2 Emission Control Measures
With the exception of the lime kiln, the emission sources in
the lime manufacturing industry can be classified as either
process emissions or fugitive emissions. The primary pollutants
resulting from these fugitive sources are PM. No specific
control measures for the lime industry are reported in the
literature for the fugitive sources. The reduction measures used
for fugitive dust sources at portland cement manufacturing
facilities may also be applicable at lime manufacturing
industries.
Air pollution control-devices for lime kilns are primarily .
used to recover product or control fugitive dust and PM
emissions. Calcination kiln exhaust is typically routed to a
cyclone for product recovery, and then routed through a fabric
filter or ESP's to collect fine particulate emissions. Other
emission controls found at lime kilns include wet scrubbers
(typically venturi scrubbers). How well these various air
pollution control devices perform, relative to vapor phase
mercury emissions in lime production, is not well documented.
The control efficiencies are expected to be similar to those
observed in the production of portland cement because of the
similarities in the process and control devices.
7.2.3 Emissions
Mercury emissions from fuel combustion will occur from the
lime kiln (calcination) as shown in Figure 7-2 by a solid circle.
Mercury that may be present in the limestone-can"potentially also
be emitted from the kiln. All other potential emission sources
in the process are expected to be very minor contributors to
overall mercury emissions. Emissions resulting from all five
7-12
-------
processing steps include particulate matter. Additionally,
emissions from the lime kiln include other products of fuel
combustion such as 862, NOX, and CO.
Representative estimates of mercury emissions from lime
manufacturing are not possible based on the available data from
lime kilns in the U.S. An ongoing EPA study to update AP-42,
Section 8.15, on lime manufacturing emission factors has reviewed
and summarized test data for lime calcining at 93 kilns.79
Pollutants identified and noted in a summary of the test data did
not indicate any mercury emissions and gave little or no
indication that emissions tests at lime kilns have sampled and
analyzed for trace metals. However, one previous study provided
1983 mercury emission test data from five Wisconsin lime plants.
Emission estimates, based on mass balances generated from
information for mercury content in limestone from the five
operating lime kilns in Wisconsin in 1983, revealed mercury
emission estimates of 18 kg/yr (39 Ib/yr) for all the kilns
combined.80 In 1983, these five lime plants produced
0.29 x 10^ Mg (0.32 x 10^ tons) of lime. 1 Assuming uniform
emissions for each ton of production suggests that 5.5 x 10"^ g
(1.2 x 10"4 Ib) of mercury were emitted for each Mg (ton) of lime
produced. These data do not account for any differences in fuel
used to heat the kilns or any differences in raw materials used.
However, because one-third of the lime kilns are fired with
natural gas, which contains no mercury, estimated annual
emissions should be reduced to reflect the differences in fuels
(see Appendix A).
In the previous section, an emission factor for mercury
emissions from the production of portland cement was estimated
using the results of emission testing at 15 cement" kilns. This
estimated emission factor was 8.7 x 10"2 g (1.7 x 10"4 Ib) of
mercury emitted for each Mg (ton) of clinker produced. In the
production of portland cement and in lime production, the major
7-13
-------
source of any mercury emissions is from the kiln during the
calcination process. In addition, the basic raw material
(limestone) is the same for both products; the fuels are
generally the same, although over one-third of the lime kilns use
natural gas and oil may be used to a greater extent in portland
cement production than in lime manufacture; and the emission
controls are very similar, if not the same.
The mercury emission factor of 5.5 x 10"2 g/Mg of lime
produced (1.2 x 10"4 Ib/ton) based on the five lime kilns in
Wisconsin has a high level of uncertainty. The material
composition could vary significantly across the country, and the
fuel type(s) used in Wisconsin may not be representative of these
used nationwide. However, based on the overall similarity of the
calcining process in lime manufacture with portland cement
production and the similarities in the two emission factors, the
emission factor based on the five Wisconsin kilns may be useful
to provide an order of magnitude estimate of mercury emissions
from lime manufacture.•
7.3 CARBON BLACK PRODUCTION
Carbon black is produced by pyrolizing petrochemical oil
feedstock. A compilation of facilities, location, type of
process, and annual capacity is presented in Table 7-2. A
description of the process used to manufacture carbon black and
the emissions resulting from the various operations is presented
below.
7.3.1 Process Description82
Carbon black is produced by partial combustion of
hydrocarbons. The most predominantly used process (which
accounts for more than 98 percent of carbon black produced) is
based on.a feedstock consisting of a highly aromatic
petrochemical or carbo chemical heavy oil. Mercury can be
7-14
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TABLE 7-2. CARBON BLACK PRODUCTION FACILITIES
Company
Cabot Corporation
North American Rubber Black Division
Chevron Corporation
Chevron Chemical Company, subsidiary
Olevins and Derivatives Division
Degussa Corporation
Ebonex Corporation
General Carbon Company
Hoover Color Corporation
J.M. Huber Corporation
Phelps Dodge Corporation
Colombian Chemical Company, subsidiary
Sir Richardson Carbon & Gasoline Company
Witco Corporation
Continental Carbon Company, subsidiary
Location-
Franklin, Louisiana
Pampa, Texas
Villa Platte, Louisiana
Waverly, West Virginia
Cedar Bayou, Texas
Aransas Pass, Texas
Belpre, Ohio
New Iberia, Louisiana
Melvindale, Michigan
Los Angeles, California
Hiwassee, Virginia
Baytown, Texas
Borger, Texas
Orange, Texas
El Dorado, Arkansas
Moundsville, West Virginia
North Bend, Louisiana
Ulysses, Kansas
Addis, Louisiana
Big Spring, Texas
Borger, Texas
Phenix City, Alabama
Ponca City. Oklahoma
Sunray, Texas
Type of
process"
F
F
F
F
A
F
F '
F
C
C
C .
F
FandT
F
F
F
F
F
F
F
F
f
P
P
TOTAL
Annual capacity5
103 Mg
141
32
127
82
9
57
59
91
4
0.5
0.5
102
79
61
50
77
109
36
66
52
98
27
fifi
45
1,471
10elbs
310
70
280
180
20
125
130
200
8
1
1
225
175
135
110
170
240
80
145
115
215
60
14?
100
3,240
Source: Reference 16.
"A = acetylene decomposition %
C = combustion
•F = furnace
T = thermal
bCapacities are variable and based on SRI estimates as of January 1, 1991
7-15
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expected to be present in the feedstock. Although the mercury
content in the feedstock used to manufacture carbon black is not
known, mercury content in- petroleum crude is reported to range
between 0.023 and 30 parts per million (ppm) by weight.83
Figure 7-3 contains a flow diagram of this process.
Three primary raw materials used in this process are,
preheated feedstock (either the petrochemical oil or
carbochemical oil), which is preheated to a temperature between
150 and 250°C (302 and 482°F), preheated air, and an auxiliary
fuel such as natural gas. A turbulent, high-temperature zone is
created in the reactor by combusting the auxiliary fuel, and the
preheated oil feedstock is introduced in this zone as an atomized
spray. In this zone of the reactor, most of the oxygen would be
used to burn the auxiliary fuel resulting in insufficient oxygen
to combust the oil feedstock. Thus, pyrolysis (partial
combustion) of the feedstock is achieved, and carbon black is
produced. Most of the mercury present in the feedstock will be
emitted in the hot exhaust gas from the reactor.
The product stream from the reactor is quenched with water,
and any residual heat in the product stream is used to preheat
the oil feedstock and combustion air before recovering the carbon
in a fabric filter. Carbon recovered in the fabric filter is in
a fluffy form. The- fluffy carbon black may be ground in a
grinder, if desired. Depending on the end use, carbon black may
be shipped in a fluffy form or in the form of pellets.
Pelletizing is done by a wet process in which carbon black is
mixed with water along with a binder and fed into a pelletizer.
The pellets are subsequently dried and bagged prior to shipping.
7.3.2 Emission Control Measures
82
.High-performance fabric filters are reported to be used to
control PM emissions from main process streams-- during the
manufacture of carbon black.. It is reported that- the fabric
7-16
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ATMOSPHERIC
Burner
Tux
V»nt to
Vacuun
<0ptlon«. Clo,.*-Loop ««„.,.
Dry»r Purg* Goi
(Op-Mon.!*-? I
Oust lag FH-tn-
To Storag*
Figure 7-3. Process flow diagram for carbon black-
manufacturing process. ^
7-17
-------
filters can reduce PM emissions to levels as low as 6 mg/m3
(normal- m3) . Mercury emissions from the reactor are primarily in
the vapor phase and not as particulate. These emissions will
proceed through the main process streams to the fabric filters.
If the mercury remains in the vapor phase, the mercury control
efficiency by the fabric filters is expected to be low. If the
product gas stream is cooled to below 170°C (325°F), the fabric
filter may capture a significant fraction of the condensed
mercury, thus providing a high degree of emission control.
7.3.3 Emissions
The processing unit with the greatest potential to emit
mercury'is the reactor. Mercury emission sources are indicated
in Figure 7-3 by solid circles. Mercury, which is present in the
oil feedstock, can potentially be emitted during the pyrolysis
step. However, no data are available on the performance of the
fabric filter control systems for mercury emissions. The only
available data are for emissions from the oil-furnace process.
These data show mercury emission to be.0.15 g/Mg (3 x 10"4 lb/
ton) from the main process vent.84 The source of these data
could not be obtained in order to verify the validity of the
emission factors. Because the factors are not verified, they
should be used with extreme caution.
7.4 BYPRODUCT COKE PRODUCTION
Byproduct coke, also referred to as metallurgical coke, is
so named because it is produced as a byproduct when coal is
distilled (in the absence of oxygen) to recover volatiles. These
volatiles are refined to produce clean coke-oven gas, tar,
sulfur, ammonium sulfate, and light oil. Table 7-3 contains a
list of byproduct coke oven facilities reported to be in
operation in 1991.85 A description of the process used to
manufacture byproduct coke and the emissions resulting from the
various operations is presented below.
7-18
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TABLE 7-3. BYPRODUCT COKE PRODUCERS IN
THE UNITED STATES IN 1991
Facility
Acme Steel, Chicago, IL
Armco, Inc., Ashland, KY
Armco, Inc., Middleton, OH
Bethlehem Steel, Bethlehem, PA
Bethlehem Steel, Burns Harbor, IN
Bethlehem Steel, Lackawanna, NY
Bethlehem Steel, Sparrows Point, MD
Geneva Steel, Orem, UT
Gulf States Steel, Gadsden, AL
Inland Steel, -East Chicago, IN
LTV Steel, Pittsburgh, PA
LTV Steel, Chicago, IL
LTV Steel, Cleveland, OH
LTV Steel, Warren, OH
National Steel, Granite City, IL
National Steel, Ecorse, Ml
USS, Div. of USX Corp., Clairton, PA
USS, Div. of USX Corp., Gary, IN
Wheeling-Pittsburgh Steel, East Steubenville,
WV
Number of
batteries
2
2
3
3
2
2
3
1-
2
6
5
1
2
1
2
1
12
6
4
Total
number of
ovens
100
146
203
284
164
152
210
208
130
446
315
60
126
85
90
78
816
422
224
Total
capacity,
tons per day
1,600
2,700
4,535
•3,944
4,380
1,872
4,069
2,250
2,800
5,775
5,404
1,600
3,200
1,500
1,520
925
12,640
7,135
3,800
Source: Reference 85.
7-19
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7.4.1 Process Description73'86
Coke is currently produced in two types of coke oven
batteries: the slot oven byproduct battery and the nonrecovery
battery. The slot oven byproduct type is the most commonly used
battery. Over 99 percent of coke produced in 1990 was produced
in this type of battery. The nonrecovery battery, as^ the name
suggests, is one where the products of distillation are not
recovered and are immediately combusted to provide energy within
the plant. The nonrecovery battery is currently 'used at only one
location; however, it is expected to be a more popular choice
when existing plants are reconstructed. Figures 7-4 and 7-5
present the general layout and the emission points of a typical
byproduct coke oven battery.
* a
The byproduct coke oven battery consists of a series
(ranging from 10 to 100) of narrow ovens, 400- to 600-mm- (16- to
24-inch) wide, and 12- to 18-meter (40- to 60-foot) long. The
height of the ovens may range between 3 and 6 meters (10 and
20 feet). Depending on the dimensions, the production capacity
may range between 7.5 and 39 tons of coke per batch. A heating
flue is located between each oven pair.
Pulverized coal (which is the feedstock) is fed through
ports located on the top, by a car (referred to as a larry car in
the industry) that travels on tracks along the top of each
battery. The ports are sealed upon charging, and gaseous fuel
(usually cleaned coke oven gas) is combusted in the flues located
between the ovens to provide the energy for the pyrolysis. The
coking process takes place for between 12 and 20 hours, at the
end of which almost all the volatile matter produced from the
coal is driven off--thus forming coke. The coke is then
unloaded from the ovens through vertical doors on each end of the
oven into a rail car where it is quenched by spraying several
thousand gallons of water. At the end of the- coking cycle,- the
maximum temperature at the center of the coke mass could be as
7-20
-------
I
to
H
._ ,, —Srondplpe Copi
Quenching r^ r r
Emitiiont Coa) pof,, Collector
^Tc*..* \^^"= "--\i»*
Waile
Slack
Coke Guide
Pusher Car
Figure 7-4. Schematic of byproduct coke oven battery. ^
-------
0 Pushing minions
(2) Charging emissions
(3) Door emissions
0 Topsidt tmissions
(|) Battery undcrf irt emissions
Figure 7-5. Types of air pollution emissions from coke
oven batteries.7^
7-22
-------
high as 1150°C (2100°F); therefore, the quenching is performed to
cool down the coke and to prevent complete combustion of the coke
upon exposure to air. The rail car then unloads the coke in a
separate area where the coke is allowed to cool further.
Mercury is present in coal in appreciable quantities.
Table 6-4 presented data pertaining to mercury levels in various
types of U.S. coals. Depending on the type of coal used, the
mercury content can be as high as 8 ppm by weight; however,
values of about 1 ppm are more typical. The volatiles recovered
from the coking operation will, therefore, contain mercury.
7.4.2 Emission Control Measures86
The PM emissions resulting from coal preparation
(pulverizing, screening, and blending) are controlled by
cyclones. Oven charging produces PM and VOC emissions. • The PM
emissions are reduced by process modifications such as staged or
sequential charging of coal into the coke oven.
Leaks of VOC through doors are reduced by door cleaning and
maintenance, rebuilding of doors, and manual application of lute
(seal) material. Charge lid and offtake leaks are reduced by an
effective patching and luting program.
Pushing coke into the quench car produces PM, VOC, and other
products of fuel combustion. Emission control devices used to
control the emissions during quenching include ESP's, fabric
filters, and wet scrubbers. These control devices are effective
\
mainly for PM control. No data are available for the performance
of these control systems for mercury emissions. However, because
they typically operate at elevated temperatures [>170°C (325°F)]
or greater, mercury removal is anticipated to be limited.
Fugitive PM generated from material handling operations such
as, unloading, storing, and grinding of coal; screening,
7-23
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crushing, storing, and loading of coke. Information pertaining
to methods of control of fugitive emissions resulting from
material handling operations is not available.
7.4.3 Emissions
Mercury, which is present in the coal, will be primarily
emitted during the coking process. During the coking cycle,
mercury emissions leak into the atmosphere through poorly sealed
doors, charge lids, and offtake caps, and through cracks which
may develop in oven brickwork, the offtakes, and collector mains.
No documentation is available pertaining to mercury emissions
resulting from the pyrolysis step. Emissions resulting from the
various process steps during the manufacture of byproduct coke
will also include PM, VOC, and CO.
7.5 PRIMARY LEAD SMELTING
Lead is recovered from a sulfide ore, primarily galena (lead
sulfide--PbS), which also contains small amounts of copper, iron,
zinc, and other trace elements such as mercury. A list of
primary lead smelters currently in operation within the United
States (U.S.) is given in Table 7-4.87 A description of the
process used to manufacture lead and the emissions resulting from
the various operations are presented below.
TABLE 7-4. DOMESTIC PRIMARY LEAD SMELTERS AND REFINERIES
Smelter
ASARCO, East Helena, MT
ASARCO, Glover, MO
Doe Run (formerly St. Joe),
Herculaneum, MO
Refinery
ASARCO, Omaha, NE
Same site
Same site
1990 Production, Mg (tons)
65,800 (72,500)
112,000 (123,200)
231,000 (254,100)
Source: Reference 87.
7-24
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7.5.1 Process Description73'88
Figure 7-6 contains a process flow diagram of primary lead
smelting. The recovery of lead from the lead ore consists of
three main steps: sintering, reduction, and refining.
Sintering is carried out in a sintering machine, which is a
continuous steel pallet conveyor belt. Each pallet consists of
perforated grates, beneath which are wind boxes connected to fans
to provide a draft through the moving sinter charge. The
sintering reactions take place at about 1000°C (1832°F) during
which lead sulfide is converted to lead oxide. Since mercury and
its compounds vaporize below this temperature, most of the
mercury present in the ore can be expected to be emitted during
sintering either as elemental mercury or as mercuric oxide.
Reduction of the sintered lead is carried out in a blast
furnace at a temperature of 1600°C (2920°F). The furnace is
charged with a mixture of sinter (80 to 90 percent of charge),
metallurgical coke (8 to 14 percent of charge), and other
materials, such as limestone, silica, litharge, and other
constituents, which are balanced to form a fluid slag. In the
blast furnace, the sinter is reduced to lead. The heat for the
reaction is supplied by the combustion of coke. Slag, consisting
of impurities, flows from the furnace and is either land
deposited or is further processed to recover zinc. The
impurities include arsenic, antimony, copper and other metal
sulfides, iron, and silicates. Lead bullion, which is the
primary product, undergoes a preliminary, treatment to remove
impurities, such as copper, sulfur, arsenic, antimony, and
nickel. Residual mercury can be expected to be emitted during
the reduction step. Further refining of the lead bullion is
carried out in cast iron kettles. Refined lead, which is 99.99
to 99.999 percent pure, is cast into pigs for shipment.
7-25
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.!
so2
Dust and Fume
Concentrated ore
Limestone
SHjca
Sinter recycle
Flue dust
Coke
1
so2
Dust and Fume
1
Dust and Fume
Denotes potential
mercury emission source
aNot at ASARCO. East Helena, Montana.
bNot at ASARCO, Glover, Missouri.
Limestone3
Silica3
Soda Ash
Sulfur3
Scrap
Zinc oxide3
Coke
A Fume
Sinter
Machine
ore
.
Coal
Sinter
fc-
i
Blast
Furnace
Slag
Limestone
Silica
Sinter recycle
Lead oxide
Coke
Bullion
t
. Dressing Dressing
-r Kettles Bum™, •" '
Ammonium chloride3
Soda ash
Sulfur
Flue dust
Coke
t
Slag fuming
furnace3'''
Zinc oxide3*
Du
mp
^
Dross
A Dust and Fume
T
Tl 1
Dross
Reverberatory
furnace
; Matte and Speiss
Refined
Lead
Figure 7-6. Typical primary lead processing scheme.73
-------
7.5.2 Emission Control Measures7^
Emission controls on lead smelter operations are employed
for controlling PM and S02 emissions resulting from the blast
furnace and sintering machines-. Centrifugal collectors
(cyclones) may be used in conjunction with fabric filters or
ESP's for PM control. The blast furnace and the sintering
machine operate at very high temperatures (in excess of 1000°C
[1832°F]), and as a result, mercury would be emitted from these
sources in vapor form. Therefore, particulate control devices
would have little effect on mercury emissions from the sintering
machine and blast furnace. However, no collection efficiency
data are available for mercury using these systems.
Control of S02 emissions is achieved by absorption to form
sulfuric acid in the sulfuric acid plants, which are commonly
part of lead smelting plants.
7.5.3 Emissions
Mercury, which may be present in the ore, may be emitted
during the sintering and blast furnace steps and in the dressing
area because these processes take place at high temperatures.
Mercury emission sources are indicated on Figure 7-6 by solid
circles.
The most recent emission factor data available for mercury
emissions from primary lead smelting are presented in
Table 7-5.88 These data represent emission factors for a custom
smelter operated by ASARCO in El Paso, Texas; this facility
ceased operating in 1985. No recent mercury emission factors are
available for the three current primary lead smelters. The
custom smelter in El Paso obtained lead ore from several sources
both within and outside the United States. These ores had a
variable mercury content depending upon the source of the ore.
Two of the three current smelters are not custom smelters; they
7-27
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TABLE 7-5. MERCURY EMISSION FACTORS FOR PRIMARY LEAD SMELTING
Process
Materials Handling:
Ore crushing
Materials Handling:
Sinter charge
mixing
Sintering Machine
leakage
Blast furnace
Slag fuming furnace
Slag pouring
Dross reverberatory
furnace
Emission factor
g/Mg
1.2a
6.5C
0.7b
1.9C
1.?d
0.45d
0.08°
Ib/ton
0.00243
0.01 3C
0.0014
0.0038C
0.0034d
0.0009d
0.00016°
Notes
Uncontrolled
Uncontrolled
Uncontrolled
Baghouse sampling
data
Baghouse sampling
data
Uncontrolled
Uncontrolled
sampling data
Source: Reference 88.
aPer ton (or Mg) of raw materials.
bPer ton (or Mg) of sinter.
cPer ton (or Mg) of concentrated ore.
dPer ton (or Mg) of lead product.
7-28
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typically process ore from the vicinity of the smelter. The two
smelters in Missouri use ore only from southeast Missouri; these
ores have a very low mercury content. The ASARCO-East Helena
plant, although a custom smelter, processes low mercury
concentrates. None of the three primary lead smelters reported
mercury emission data in the 1990 TRI, indicating that emissions
from the sources are estimated to be below the TRI reporting
threshold.
Because the data in Table 7-5 were based on ores with a
variable mercury content and the current sources of lead ore have
a low mercury content, the emission factors in Table 7-5 probably
would lead to an overestimation of current emissions. Extreme
caution should be exercised in the use of these emission factors
to predict precise current emissions; however, the factors may
provide an order of magnitude estimate. An alternative
estimating method may be to use the actual mercury content of the
ore and estimate emissions based on those data.
»
7.6 PRIMARY COPPER SMELTING
* *•• **» •*• ^ >^»** W» ^ %*«*» ^ ^ ^*^M "t^ ^ ^ t* *~ .fc A*Vrf ^ k^^lt ^. _i_ T *^ J
pyrometallurgical smelting methods. Copper ores contain small
quantities of arsenic, cadmium, lead, antimony, and other heavy
metals including mercury. Data pertaining to mercury content in
the ore are not available.
A list of primary copper smelters currently in operation
within the U.S. is given in Table 7-6." A description of the
process used to manufacture copper and the emissions resulting
from the various operations is presented below.
7-29
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TABLE 7-6. DOMESTIC PRIMARY COPPER SMELTERS AND REFINERIES
Smelter
ASARCO Inc., Hayden, AZ
Cyprus Miami Mining Co., Globe, AZ
MAGMA Copper Co., San Manuel, AZ
Copper Range Co., White Pine, Ml
Phelps Dodge, Hidalgo, NM
Chino Mines Co., Hurley, NM
ASARCO Inc., El Paso, TX
Kennecott, Garfield, UT
ASARCO Inc., Amarillo, TX
Phelps Dodge, El Paso, TX
1 992 Capacity, Mg (tons)
191,000 (210,000)
180,000 (198,000)
290,000 (319,000)
60,000 (66,000)
190,000 (209,000)
170,000 (187,000)
100,000 (110,000)
210,000(231,000)
Unknown
Unknown
Source: Reference 89.
7,6.1 Process Description73
The pyrometallurgical copper smelting process is illustrated
in Figure 7-7. The traditionally used process includes roasting
of ore concentrates to produce calcine, smelting of roasted
(calcine feed) or unroasted (green feed) ore concentrates to
produce matte, and converting of the matte to yield blister
copper product (about 99 percent pure). Typically, the blister
copper is fire refined in an anode furnace, cast into "anodes"
and sent to an electrolytic refinery for further impurity
elimination. The currently used copper smelters process ore
concentrates by drying them in fluidized bed dryers and then
converting and refining the dried product in the same manner as
the traditionally used process.
In roasting, charge material of copper concentrate mixed
with a siliceous flux (often a low grade ore) is heated in air to
about 650°C (1200°F), eliminating 20 to 50 percent of the sulfur
as S02- Portions of such impurities as antimony, arsenic, and
lead are driven off, and some iron is converted to oxide. The
7-30
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Ore Concentrates with Silica Fluxes
1 .
Fuel
Air
ROASTINGa
OR DRYINQb
d
CN
O)
I
03
O
O
Fuel
Air
OFF GAS
FLASH
SMELTING
f
Slag to Dump
(0.5% Cu)
Air
OFF GAS
MATTE (-40% Cu)
CONVERTING
OFF GAS
Natural or Reformulated Gas
Green Poles or Logs
Fuel
Air
Slag to Converter
Blister Copper (98.5% Cu)
FIRE REFINING
J
OFF GAS
• Denotes potential
mercury emission source
Anode Copper (99.5% Cu)
To Electrolytic Refinery
aFirst step in the traditionally used copper-smelting process.
bFirst step in the currently used copper-smelting process.
Figure 7-7. Typical primary copper smelter process. ^
7-31
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roasted product, calcine, serves as a dried and heated charge for
the smelting furnace. Either multiple hearth or fluidized bed
roasters are used for roasting copper concentrate. Multiple
hearth roasters accept moist concentrate, whereas fluid bed
roasters are fed finely ground material (60 percent minus
200 mesh). With both of these types, the roasting is autogenous.
Because there is less air dilution, higher SO2 concentrations are
present in fluidized bed roaster gases than in multiple hearth
roaster gases. Because mercury has a boiling point of 350°C
(660°F), most of the mercury in the ore may be emitted as an air
pollutant during roasting.
In the smelting process, either hot calcines from the
roaster or raw unroasted or dried concentrate is melted with
siliceous flux in a flash smelting furnace to produce copper
matte, a molten mixture of cuprous sulfide (Cu2S), ferrous
sulfide (FeS), and some heavy metals. The required heat comes
from partial oxidation of the sulfide charge and from burning
external fuel. Most of the iron and some of the impurities in
the charge oxidize with the fluxes to form a slag atop the molten
bath, which is periodically removed and discarded. Copper matte
remains in the furnace until tapped. Mattes produced by the
domestic industry range from 35 to 65 percent copper, with
45 percent the most common. The copper content percentage is
referred to as the matte grade. Currently, five smelting furnace
technologies are used in the U.S., reverberatory, electric,
Noranda, Outokumpu (flash), and Inco (flash). Reverberatory
furnace may operate at temperatures as high as 1500°C (2730°F).
Flash furnaces may operate at temperatures as high as 1200° .
to 1300°C (2200° to 2300°F). Even though the exact temperatures
at which the other two furnace technologies (electric and
Noranda) operate are not known, it is probable that they operate
at temperatures higher than the boiling point of mercury.
Therefore, any residual mercury that remains in the calcine may
be emitted as an air pollutant during the smelting step." " -
7-32
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Reverberatory furnace operation is a continuous process,
with frequent charging of input materials and periodic tapping of
matte and skimming of slag. Heat is supplied by combustion of
oil, gas or pulverized coal, and furnace temperature may exceed
1500°C (2730°F). Currently, a reverberatory furnace used at
ASARCO, El Paso and an Isamelt furnace at Cyprus are being
replaced with ConTop cyclone reactors (another type of flash
smelting).
For smelting in electric arc furnaces, heat is generated by
the flow of an electric current in carbon electrodes lowered
through the furnace roof and submerged in the slag layer of the
molten bath. The feed generally consists of dried concentrates
or calcines, and charging wet concentrates is avoided. The
chemical and physical changes occurring in the molten bath are
similar to those occurring in the molten bath of a reverberatory
furnace. Also, the matte and slag tapping practices are similar
at both furnaces. Electric furnaces do not produce fuel
combustion gases, so flow rates are lower and S02 concentrations
higher in the effluent gas than in that of reverberatory
furnaces.
Flash furnace smelting combines the operations of roasting
and smelting to produce a high grade copper matte from
concentrates and flux. In flash smelting, dried ore concentrates
and finely ground fluxes are injected, together with oxygen,
preheated air, or a mixture of both, into a furnace of special
design, where temperature is maintained at approximately 1200
to 1300°C (2200 to 2300°F). Most flash furnaces, in contrast to
reverberatory and electric furnaces, use the heat generated from
partial oxidation of their sulfide charge to provide much or all
of the energy (heat) required for smelting. They also produce
offgas streams containing high concentrations of S02. Other
flash furnaces, such as ConTop cyclone reactors, use oxyfuel
combustion to generate the heat required for oxidation.
7-33
-------
Slag produced by flash furnace operations typically contains
higher amounts .of copper than does that from reverberatory or
electric furnace operations. As a result, the flash furnace and
converter slags are treated in a slag cleaning furnace to recover
the copper (not conducted at the ASARCO, Hayden facility). Slag
cleaning furnaces usually are small electric furnaces. The flash
furnace and converter slags are charged to a slag cleaning
furnace and are allowed to settle under reducing conditions, with
the addition of coke or iron sulfide. The copper, which is in
oxide form in the slag, is converted to copper sulfide, is
subsequently removed from the furnace and is charged to a
converter with regular matte. If the slag's copper content is
low, the slag is discarded.
The Noranda process, as originally designed, allowed the
continuous production of blister copper in a single vessel by
effectively combining roasting, smelting, and converting into one
operation. Metallurgical problems, however, led to the operation
of these reactors for the production of copper matte. As in
flash smelting, the Noranda process takes advantage of the heat
energy available from the copper ore. The remaining thermal
energy required is supplied by oil burners, or by coal mixed with
the ore concentrates.
The final step in the production of blister copper is
converting, with the purposes of eliminating the remaining iron
and sulfur present in the matte and leaving molten "blister"
copper. All but one U. S. smelter uses Fierce-Smith converters,
which are refractory lined cylindrical steel shells mounted on
trunnions at either end, and rotated about the major axis for
charging and pouring. An opening in the center of the converter
functions as a mouth through which molten matte, siliceous flux,
and scrap copper are charged and gaseous products are vented.
Air or oxygen-rich air is blown through the molten matte. Iron
sulfide (FeS) is oxidized to iron oxide (FeO) and S02, and the
FeO blowing and slag skimming are repeated until an adequate
7-34
-------
amount of relatively pure Cu2S, called "white metal", accumulates
in the bottom of the converter. A renewed air blast oxidizes the
copper sulfide to SO2, leaving blister copper in the converter.
The blister copper is subsequently removed and transferred to
refining facilities.• This segment of converter operation is
termed the finish blow. The S02 produced throughout the
operation is vented to pollution control devices.
One domestic smelter uses Hoboken converters. The Hoboken
converter is essentially like a conventional Pierce-Smith
converter, except that this vessel is fitted with a side flue at
one end shaped as an inverted U. This flue arrangement permits
siphoning of gases from the interior of the converter directly to
the offgas collection system, leaving the converter mouth under a
slight vacuum. The Hoboken converters are also equipped with
secondary hoods to further control emissions.
Blister copper usually contains from 98.5 to 99.5 percent
pure copper. Impurities may include gold, silver, antimony,
arsenic, bismuth, iron, lead, nickel, selenium, sulfur,
tellurium, and zinc. To purify blister copper further, fire
refining and electrolytic refining are used, in fire refining,
blister copper is placed in an anode furnace, a flux is usually
added, and air is blown through the molten mixture to oxidize
remaining impurities, which are removed as a slag. The remaining
metal bath is subjected to a reducing atmosphere to reconvert
cuprous oxide to copper. Temperature in the furnace is around
1100°C (2010°F). The fire-refined copper is cast into anodes.
Further refining separates the copper from impurities by
electrolysis in a solution containing copper sulfate and sulfuric
acid. Metallic impurities precipitate from the solution and form
a sludge that is removed and treated to recover precious metals.
Copper is dissolved from the anode and deposited at the cathode.
Cathode copper is remelted and cast into bars, rods, ingots, or
slabs for marketing purposes. The copper produced is 99.95 to
7-35
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99.97 percent pure. Any mercury emission during the refining
step will only be minimal.
7.6.2 Emission Control Measures73
Emission controls on copper smelters are employed for
controlling PM and S02 emissions resulting from roasters,
smelting furnaces, and converters. Electrostatic precipitators
are the common PM control devices employed at copper smeltering
facilities.
Control of SO2 emissions is achieved by absorption to
sulfuric acid in the sulfuric acid plants, which are commonly
part of copper smelting plants.
7.6.3 Emissions
The main source of mercury will be during the roasting step
and in the smelting furnace. Converters and refining furnaces
may emit any residual mercury left in the calcine. These sources
are denoted by solid circles in Figure 7-7. Data pertaining to
mercury emissions from copper primary copper smelting facilities
are limited. One emission test report at Copper Range Company
located in White Pine, MI, containing results of metals analysis
was reviewed during this study. " This facility operates a
reverberatory furnace which is controlled by an ESP. The exhaust
stream from the converter (which is uncontrolled) is mixed with
the exhaust from the ESP outlet and is routed through the main
stack and discharged into the atmosphere. Testing for metals was
done at the main stack after the two exhaust streams (from the
ESP outlet and the converter) are mixed. Mercury emissions were
measured for three modes of converter operation, slag-blow,
copper-blow and converter idle (no blow) cycles. Mercury level
during the converter idle cycle was measured to be the highest,
corresponding .to a mercury emission rate of O:i661 Ib/hr.
Additionally, the plant capacity was reported to be approximately
7-36
-------
42 tons/hr of feed which consists of mill concentrate,- limestone,
iron pyrites, and recycled material. The actual process rate
during the test is not known. Since the feed mix varies from
facility to facility, the mercury emissions measured at Copper
Range Company, cannot be used to estimate a general mercury
emission factor that would be valid industrywide. Additionally,
Copper Range Company, is the only facility in the U. S. which
operates a reverberatory furnace. All other copper smelting
furnaces use flash furnaces which inherently produce less
emissions.
7.7 PETROLEUM REFINING
Petroleum refining involves the conversion of crude
petroleum oil into refined products, including liquified
petroleum gas, gasoline, kerosene, aviation fuel, diesel fuel,
fuel oils, lubricating oils, and feedstocks for the petroleum
industry.
As of January 1992, there were 32 oil companies in the
United States with operable atmospheric crude oil distillation
oil companies operated refiners at a total of 110 different
locations. In addition, there were 72 companies with
distillation capacities of less.than 100,000 barrels per calendar
day. A listing of all companies, specific'refinery locations,
and distillation capacities is presented in Appendix D.91
Mercury is reported to be present in petroleum crude, and
its content in petroleum crude is reported to range between 0.023
and 30 parts per million (ppm) by weight.83 A description of the
processes used in petroleum refining and emissions resulting from
the various operations is*presented below.
7-37
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7.7.1 Process Description73'9-2'93
Figure 7-8 presents a schematic of an integrated petroleum
refinery. The processes and operations shown in Figure 7-8 show
a general processing arrangement. However, it may vary among
refineries depending upon the specific products produced. The
operations at petroleum refineries are classified into five
general categories, as listed below:
1. Separation processes,
2. Petroleum conversion processes,
3. Petroleum treating processes,
4. Feedstock and product handling, and
5. Auxiliary facilities.
Separation processes--
Constituents of crude oil include paraffinic, naphthenic,
and aromatic hydrocarbon compounds. Impurities may include
sulfur, nitrogen, and metals. Three separation processes used to
separate these constituents include: atmospheric distillation,
vacuum distillation, and recovery of light ends (gas processing).
Atmospheric distillation results in the formation of bottoms
consisting of high-boiling-point hydrocarbons. Topped crude
withdrawn from the bottoms of atmospheric distillation can be
separated further by vacuum distillation.
In vacuum distillation, the topped crude is heated in a
process heater to temperatures ranging from 370° to 425°C
(700° to 800°F) and subsequently flashed in a multi-tray vacuum
distillation column, operating at vacuums ranging from 350 to
1,400 kg/m2 (0.5 to 2.0 psia). Standard petroleum fractions
withdrawn from the vacuum distillation include lube distillates,
vacuum oil, asphalt stocks, and residual oils.
Distillation" is carried out at temperatures higher than the
boiling point of mercury. Therefore, the distillation step can
be expected to be the primary source of mercury emissions.
7-38
-------
Got
Liquefied petroleum qas
Crudt oil-*-
Alternate
operation!
and
products
dependent
on kind pi
crude oil
being run
Automobiles
*• Home healing
ATMOSPHERIC
OR VACUUM
DISTILLATION
Roads
*-Wo« paper
Figure 7-8. Schematic of an example integrated petroleum refinery.
-------
Conversion processes--
Conversion processes include cracking, coking, and
visbreaking, which break large molecules into smaller molecules;
isomerization and reforming processes to rearrange the structures
of molecules; and polymerization and alkylation to combine small
molecules into larger ones. Residual mercury from the separation
processes is probably emitted during the conversion processes.
Catalytic cracking--using heat, pressure, and catalysts--
converts heavy oils into lighter products. Feedstocks are
usually gas oils from atmospheric distillation, vacuum
distillation, coking, and deasphalting processes, and they have a
boiling range of 340° to 540°C (650° to 1000°F). Two types of
cracking units, the fluidized catalytic cracking (FCC) unit and
the moving-bed catalytic cracking unit, are used in the
refineries. Figure 7-9 presents a schematic of a fluid catalytic
QO
cracking unit. "
Visbreaking is a thermal cracking process used to reduce the
viscosity of the topped crude or vacuum distillation residues.
The feedstock is heated and thermally cracked at a temperature
ranging between 455° and 480°C (850° and 900°F) and pressure
ranging between 3.5 and 17.6 kg/cm2 (50 and 250 psia). The
cracked products are quenched with gas oil and flashed into a
fractionator. The vapor overhead from the fractionator is
separated into light distillate products. A heavy distillate is
recovered from the fractionator liquid.
Coking is also a thermal cracking process used to convert
low value residual fuel oil to higher value gas oil and petroleum
coke. This process is carried out. at high temperature and low
pressure, and the resulting products include petroleum coke, gas
oils, and lighter petroleum stocks. '-"-- '. -"
Equipment commonly used during conversion includes process -
heaters and reformers. Process heaters are used'to raise"the
7-40
-------
Fncllonalar
UgMCyocon
h
R^i
COFUHMC*
BfWMIOf
PwfletMa
Coolfoi
Owte*'
Cembiaaon
MrBkmr
Figure 7-9. Schematic of fluidized bed catalytic
cracking unit. 92
7-41
-------
temperature of petroleum feedstocks to a maximum of 510°C
(950°F). Fuels burned include refinery gas, natural gas,
residual fuel oils, or combinations. Reformers are reactors
where the heat for the reaction is supplied by burning fuel. For
example, the reforming of natural gas by steam takes place in a
reformer equipped with tubes. The natural gas and steam are
introduced through the tubes, and the energy for the reaction is
supplied by burning fuel in burners located outside the tubes.
The conversion steps, cracking, coking, and visbreaking,
described above can be expected to be the secondary sources of
mercury emissions.
Treatment processes- -
Petroleum treatment processes, include hydrodesulfurization,,
hydrotreating, chemical sweetening, acid gas removal, and
deasphalting. These treatment methods are used to stabilize and
upgrade petroleum products. Removal of undesirable elements,
such as sulfur, nitrogen, and oxygen, is accomplished by
hydrodesulfurization, hydrotreating, chemical sweetening, and
acid gas removal. Deasphalting is carried out to separate
asphaltic and resinous materials from petroleum products.
Hydrotreating is a process in which the oil feed is treated by
mixing with hydrogen in a fixed-bed catalyst reactor. Removal of
acid gas involves controlling emissions of S02. Elemental sulfur
is recovered as a byproduct.
Asphalt blowing is carried out by blowing air through the
vacuum distillation residue to polymerize asphalt by oxidation.
Feed is preheated to a temperature ranging between 200° and 320°C
(400° and 600°F) prior to blowing air. The off gases (asphalt
fumes) are commonly treated (for VOC control) .in an incinerator
prior to being released into the atmosphere.
Distillate sweetening is a catalytic process carried out in
a fixed-bed catalytic reactor in which sulfur is introduced in
7-42
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the sour distillate along with small quantities of caustic and
air.
Any residual mercury left over in the feedstock after the
separation and conversion steps can be expected to be emitted
during the treatment step.
Feedstock and product handling--
This includes storage, blending, loading, and unloading of
petroleum crude and products. No mercury emissions are expected
during these steps.
Auxiliary facilities--
Auxiliary facilities include boilers, gas turbines,
wastewater treatment facilities, hydrogen plants, cooling towers,
and sulfur recovery units. Boilers and gas turbines cogeneration
units within petroleum refineries may burn refinery gas.
7.7.2 Emission Control Measures
Control of VOC (and in some instances, CO) emissions from
distillation, catalytic cracking, coking, blowdown system,
sweetening, and asphalt blowing is achieved by flares. In some
instances, the VOC-laden gas stream is also used as fuel in
process heaters.
Control of PM emissions from catalytic cracking is achieved
by using cyclones in conjunction with ESP's.
7.7.3 Emissions
Emissions of mercury can be expected during the process
steps where petroleum crude is processed at high temperatures,
such as the distillation, cracking, visbreaking, and other
conversion steps. Potential mercury emission sources are . •
identified in Figures 7-8 and 7-9 by solid circles. Other
7-43
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emissions from petroleum refining operations include mainly PM,
VOC, and products of fuel combustion. An emission factor for
uncontrolled emissions from the fluid coking unit in the
conversion step was cited in SPECIATE to be 3 x 10"5 g/liter
(0.0105 lb/ 1,000 barrels) of fresh feed.94 The source of these
data could not be obtained in order to verify the validity of the
emission factors. Because the factors are not verified, they
should be used with extreme caution. The only additional data
available pertaining to mercury emissions are those documented
for process heaters and reformers. Based on a series of emission
tests carried out in California, emission estimates for mercury
are available for refinery gas-fired process heaters, boilers,
gas turbine cogeneration units, and asphalt fume incinerators.95
Table 7-7 contains emission factors for mercury from the above
mentioned sources.
TABLE 7-7. MERCURY EMISSION FACTORS FOR MISCELLANEOUS SOURCES
AT PETROLEUM REFINING FACILITIES.
Process Unit
Process heater (refinery gas-fired)
Boiler (refinery gas-fired)
Gas-fired cogeneration unit (refinery gas-fired)
Asphalt fume incinerator (this is an emission control
device to treat the fumes resulting from asphalt
blowing operation)
- Blow cycle
- No blow cycle
Mercury emission factor
kg/1015J
0.09
6.0
2.8
3.4
3.7
lb/10l2Btu
0.2
14
6.6
8
8.5
Source: Reference 95.
The emission factors in Table 7-7 were derived based on an
emission test. Details pertaining to the process conditions
during the test are not known. Additionally, the emission factor'
for the asphalt fume incinerator is based on measurements taken
at the outlet of the fume incinerator, which is an emission
control device for the asphalt blowing process. Details :
7-44
-------
pertaining to any auxiliary fuel used in the fume incinerator are
not known. Therefore, it is not possible to estimate how much of
the mercury measured is contributed by the fuel used in the fume
incinerator as opposed to that created by the asphalt blowing
process. Additionally, since the asphalt fume incinerator is
employed primarily for VOC control, the emission factors for
mercury given in Table 7-7 represent uncontrolled emission
factors.
7.8 OIL SHALE RETORTING
Oil shale is a marlstone-type sedimentary inorganic material
containing complex organic polymers. These complex organic
polymers are high-molecular-weight solids. Mercury may be
expected to be present in.oil shale. However, no data are
available pertaining to mercury content in oil shale. The
composition of inorganic and organic constituents of oil shale is
completely dependent on deposit location.96
Thermal decomposition of oil shale is referred to'as oil
shale retorting. A description of the processes used in oil
shale retorting and einj.ssj.ons resulting fjroin the VS.ITJ.OUS
operations is presented below.
7.8.1 Process Description96'97
The retorting process breaks down the high molecular weight
complex organic polymers contained in oil shale (referred to as
kerogen) into liquid, gaseous, and solid products. The oil shale
pyrolysis process is carried out approximately at a temperature
of 480°C (900°F). Pyrolysis reduces the kerogen into coke, gas,
and liquid. Additional details pertaining to the composition of
the oil and gaseous products are not available:
Processing of oil shale involves four steps: feed :
preparation, retorting, product recovery, and waste disposal.
7-45
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There are three general classes of oil shale feed preparation and
retort technology: (l) mining, followed by surface retorting,
(2) true in situ (TIS), and (3) modified in situ (MIS). In
surface retorting, oil shale is mined by conventional underground
or open pit methods, and the oil is recovered in an above-ground
retort. With TIS technology, the retorting takes place
underground in the oil shale deposit. Modified in situ
technology is a cross between surface and TIS technologies where
the initial 15 to 40 percent of the oil shale is mined and
retorted in a surface facility, and the remaining 60 to
85 percent of the shale is retorted in-place underground.
The retorting step may be expected to be the primary source
of mercury emissions.
7.8.2 Emission Control Measures
Flares are reported to be used to control VOC emissions
resulting from the retorting process. No other details are
available pertaining to air pollution devices used in oil shale
processing operations.
7.8.3 Emissions
At this time, there are no commercial oil shale retorting
operations being conducted in the United States.
7.9 GEOTHERMAL POWER PLANTS98
N
Geothermal power plants are either dry-steam or water-
dominated and emitted an estimated 1.3 Mg (1.4 tons) of mercury
in 1992. For dry-steam plants, steam is pumped from geothermal
reservoirs to turbines at a temperature of about 180°C (360°F)
and a pressure of 7.9 bars absolute. For water-dominated plants,
water exists in the producing strata at a temperature of
approximately 270°C (520°F) and at a pressure slightly higher
7-46
-------
than hydrostatic. As the water flows towards the surface,
pressure decreases and steam is formed, which is used to operate
the turbines. There are currently 18 geothermal power plants
operating in the United States." Table 7-8 lists the names,
locations, and capacities of these facilities.
Mercury can be expected to be present in the steam and water
because it is recovered from beneath the earth's surface.
However, no data on the mercury content of steam or water cycled
through geothermal facilities are available.
7.9.1 Emission Control Measures
No information is available pertaining to air pollution
•
control systems used in geothermal power plants.
7.9.2 Emissions
Mercury emissions at geothermal power plants are documented
to result from two sources: off-gas ejectors, and cooling
towers. Table 7-9 contains the mercury emission factors for
Q fl
1977.y° No process data are given in the documentation
containing the test results and the primary source of these data
could not be obtained in order to verify the validity of the
emission factors. If significant process modifications or
changes in control strategies have been incorporated since 1977,
the emission factors reported in Table 7-9 may no longer be
valid.
7-47
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TABLE 7-8. CURRENT OPERATING GEOTHERMAL POWER PLANTS
IN THE UNITED STATES IN 1992
Facility
The Geysers, CA
Salton Sea, CA
Heber, CA
East Mesa, CA
Coso, CA
Casa Diablo, CA
Amedee, CA
Wendel, CA
Dixie Valley, NV
Steamboat Hot Springs, NV
Beowawe Hot Springs, NV
Desert Peak, NV
Wabuska Hot Springs, NV
Soda Lake, NV
Stillwater, NV
Empire and San Emidio, NV
Roosevelt Hot Springs, UT
Cove Fort, UT
Type
Dry-steam
Water-dominated
Water-dominated
Water-dominated
Water-dominated
Water-dominated
Water-dominated
Water-dominated
Water-dominated
Water-dominated
Water-dominated
Water-dominated
Water-dominated
Water-dominated
Water-dominated
Water-dominated
Water-dominated
Water-dominated
Net capacity (MW)
1,805.7
218.3
47.0
106.0
247.5
34.0
2.0
0.7
57.0
19.3
16.7
9.0
1.7
15.7
12.5
3.2
20.0
12.1
Total . 2,628.4
Source: Reference 99.
TABLE 7-9. MERCURY EMISSION FACTORS FOR GEOTHERMAL
POWER PLANTS
Source
Off-gas ejectors
Cooling tower exhaust
Emission factor range,
g/Mwe/hr
0.00075 - 0.02
0.026 - 0.072
Average emission factor
g/Mwe/hr
0.00725
0.05
Ib/Mwe/hr
0.00002
0.0001
Source: Reference 98.
7-48
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SECTION 8
EMISSIONS FROM MISCELLANEOUS FUGITIVE AND AREA SOURCES
8.1 MERCURY CATALYSTS
Mercury catalysts are used in the production of polyurethane
and vinyl chloride. According to 1991 data, U.S. consumption of
refined mercury for "other chemical and allied products" includes
catalysts for plastics and miscellaneous catalysts. This entire
category was reported to have consumed 18 Mg (20 tons) of mercury
metal in 1991, which represents about four percent of the total
mercury consumed in the U.S.1^^
8.1.1 Process Description
Catalysts involved in the production of polyurethane have
been composed of the phenylmercuric compounds (CgHgHg"1") , but few
facilities currently uss this catalyst. Ths location cf these
facilities is unknown.
Two processes can be used to manufacture vinyl chloride:
one process based on acetylene uses mercuric chloride on carbon
pellets as a catalyst, and the other is based on the
oxychlorination of ethylene. Vinyl chloride is always produced
by oxychlorination except at Borden Chemical and Plastics
Corporation. Borden Chemical and Plastics produces about
136,000 Mg (149,600 tons) of vinyl chloride using mercuric
chloride as a catalyst with acetylene. This represents
approximately 2.5 percent of the total U.S. production.16
Figure 8-1 shows a flow diagram for this manufacturing process.
To produce 136,000 Mg (149,600 tons) of vinyl chloride requires
57,500 Mg (63,000 tons) acetylene, 79,000 Mg (87,000 tons)
8-1
-------
ACETYLENE AND HCI
OD
I
(0
CATALYST
ACETYLENE
HYDROGEN CHLORIDE
. VINYL CHLORIDE
(STABLIZED)
PHENOL
BOTTOMS TO POT STILL
• DENOTES POTENTIAL MERCURY EMISSION SOURCE
Figure 8-1. Vinyl chloride process using a mercuric chloride catalyst.
-------
anhydrous hydrogen chloride, and; 131 Mg (144 tons) of mercuric
chloride impregnated carbon pellets. The yield is 80 to
85 percent vinyl chloride.101 This reaction occurs when the
anhydrous hydrogen chloride and acetylene are mixed in a reactor
vessel with the mercuric chloride catalyst contained on carbon
pellets. Since the reaction is exothermic, the effluent gases
are cooled by heat exchange, and then condensed and fractionated
in a refrigerated column. Further fractionation in another
refrigerated column will remove the vinyl chloride for
stabilization with phenol and storage.101
8.1.2 Emission Control Measures
No specific information was found in the literature
concerning specific control measures for mercury emissions. The
use of a heat exchange and refrigeration column in the production
process will provide for a significant reduction in mercury
emissions, particularly in the refrigerated column.
8.1.3 Emissions
In Figure 8-1, if the heat exchanger is operated at a low
temperature, mercury condensation will occur and eventually be
found in the bottoms. However, if the temperature is not
sufficient to provide for condensation, an appreciable quantity
of the mercury from the reactor will be entrained with the
acetylene and HC1.
No emission factors were found in the literature, and no
test data that could be used to calculate emission factors was
found. In the 1990 TRI inventory, Borden Chemical and Plastics
reported no mercury emissions at the Louisiana production
facility.5 ' •-•-•• •
8-3
-------
8.2 DENTAL ALLOYS
Dental amalgams used to fill cavities in teeth-include an
appreciable quantity of mercury. The amalgamation process is
fairly generic industrywide, although some dental facilities use
ready-made dental capsules to reduce worker exposure to elemental
mercury.15
Dental fillings contain mixtures of metals, usually silver
(67 to 70 percent), tin (25 to 28 percent), copper (0 to
5 percent), and zinc (0 to 2 percent), which are blended with
mercury in a 5:8 proportion to form an amalgam.15
8.2.1 Process Description
The dental alloy and mercury are placed inside a two-part
plastic capsule that contains a pestle. Mercury is added with a
dispenser that delivers a drop (or "spill") when a button is
pressed. Usually, only one or two drops are necessary to mix the
amalgam. The plastic capsule is then closed and placed in an
agitator where the contents are mixed for approximately
15 seconds. Once mixing is completed, the capsule is opened to
remove the amalgam, which is then placed in a container for
immediate application in the cavity.15
8.2.2 Emission Control Measures
There are no emission controls noted for handling mercury
used in amalgam production. One work practice is the use of
ready-made dental capsules that already contain a pestle and
premeasured amounts of mercury and alloy.15 This would eliminate
any unnecessary handling and accidental spilling of mercury.
8-4
-------
8.2.3 Emissions
According to the Bureau of Mines (1991), industrial
consumption of mercury for dental equipment and supplies was
27 Mg (30 tons).100 A study in 1980 estimated that approximately
2 percent of the mercury used in dental preparations would be
emitted due to spills and scrap.102 This corresponds to an
emission factor of 20 kg/Mg (40 Ib/ton) of mercury used. The
percentage of the total quantity of mercury in dental equipment
and supplies that is used for dental alloys is not known.
8.3 MOBILE SOURCES
Gasoline-powered motor, on-roadr light-duty vehicles
comprise the most significant mobile emission sources. According
to the Motor Vehicle Manufacturers Association (MVMA), the total
distance travelled for all vehicles in the U.S. in 1990 was
3,457,478 million kilometers (2,147,501 million miles).103
8.3.1 Emissions
Historically, the major emissions measured from mobile
sources are CO, NOX, and hydrocarbons (HC); AP-42, Volume II
compiles emission factors for these specific pollutants among the
different motor vehicle classes. A 1983 study indicated an
estimated mercury emission factor of 1.3 x 10"3 milligram (mg)
per kilometer (km) (4.6 x 10"9 Ib/mile) for motor vehicles
without resolution of emission rates into vehicle types.104 The
population of vehicles studied was 81.9 percent gasoline-powered
passenger cars, 2.4 percent gasoline-powered trucks, and
15.7 percent diesel trucks. This emission factor should be used
cautiously as it was based on a 1977 ambient sampling1study,
which was before the widespread use of catalytic converters and
unleaded gasoline, and before State-regulated inspection and
maintenance programs were widely mandated. In 1977,
8-5
-------
diesel-powered vehicles had not yet been regulated for emission
controls, especially for particulates.
A 1979 study characterized regulated and unregulated exhaust
emissions from catalyst and non-catalyst equipped light-duty
gasoline operated automobiles operating under malfunction
conditions.105 An analysis for mercury was included in the study
but no mercury was detected. The analytical minimum detection
limit was not stated.
A more recent 1989 study measured the exhaust emission rates
of selected toxic substances for two late model gasoline-powered
passenger cars.106 The two vehicles were operated over the
Federal Test Procedure (FTP) ,- the Highway Fuel Economy Test
(HFET), and the New York City Cycle (NYCC). Mercury was among
the group of metals analyzed but was not present in detectable
quantities. The analytical minimum detection limits for mercury
in the three test procedures were: FTP 0.025 mg/km (8.9 x
10"8 Ib/mile) HFET 0.019 mg/km (6.7 x 10"8 Ib/mi), and NYCC
0.15 mg/km (53.2 x 10"8 Ib/mi).107 These minimum detection
limits are over ten times higher than the estimated emission
factor presented in the 1983 study.
8.4 CREMATORIES
Mercury resulting from the thermal instability of mercury
alloys of amalgam tooth fillings during cremation of human bodies
may potentially be a source of mercury air emissions. In 1991,
there were about 400,500 cremations in the slightly more than
1,000 crematories located throughout the United States.108
Table 8-1 lists the number of crematories located in each State
and the estimated number of cremations performed in each State.
No information was available on the location of individual
crematories.109
8-6
-------
TABLE 8-1. 1991 U.S. CREMATORY LOCATIONS BY STATE
State
Alabama
Alaska
Arizona
Arkansas
California
Colorado
Connecticut
Delaware
District of
Columbia
Florida
Georgia
Hawaii
Idaho
Illinois
Indiana
Iowa
Kansas
Kentucky
Louisiana
Maine
Maryland
Massachusetts
Michigan
Minnesota
Mississinni
Missouri
No. of
crematories
6
7
26
13
141
28
10
4
1
95
14
10
12
44
21
15
10
5
6
4
• 17
13
38
18
4
19
No. of
cremations3
1,138
790
10,189
1,787
86,374
7,432
4,260
1,165
b
46,775
2,684
3,495
1,949
12,083
3,636
2,241
1,559
1,192
1,853
2,656
5,587
8,104
13,431
5,662
450
4,637
State
Montana
Nebraska
Nevada
New
Hampshire
New Jersey
New Mexico
New York
North Carolina
North Dakota
Ohio
Oklahoma
Oregon
Pennsylvania
Rhode Island
South
Carolina
South Dakota
Tennessee
Texas
Utah
Vermont
Virginia
Washington
West Virginia
Wisconsin
\AA/nminn
- - ,_..... .o
No. of
crematories
12
6
11
6
16
9
40
24
1
41
9
34
44
5
10
4
8
36
5
5
25
46
6
29
2
No. of
cremations
2,502
1,139
5,009
1,842
14,427
2,134
23,946
4,749
b
12,552
1,372
9,020
12,153
1,842
1,764
b
1,712
9,340
769
1,570
6,097
15,673
582
5,541
h
a1990 data. 1991 data unavailable.
"No information available.
Source: Reference 108.
8-7
-------
No data are available for the average quantity of mercury
emitted for a cremation in the United States. Only three
estimated levels have been cited for European countries
(Switzerland, Germany, and the UK) with an estimated emission of
one gram of mercury per cremation recommended as a typical
value.110 This emission factor is not considered to be
applicable to cremations in the United States. There is a
substantial difference in the frequency of cremations in Europe
compared to the United States. In addition, there is a
considerable variation in the overall dental care programs in the
United States compared to Europe which may result in a difference
in the average number of mercury amalgam fillings per person.
The average number of fillings per person and the average mercury
content per filling have a direct impact on the estimated mercury
emissions. The considerable potential differences between the
United States and Europe precludes an accurate estimate of
mercury emissions from this source.
8.5 PAINT-USE
Four mercury compounds--phenylmercuric acetate,
3-(chloromethoxy) propylmercuric acetate, di(phenylmercury)
dodecenylsuccinate, and phenylmercuric oleate--have been
registered as biocides for interior and exterior paint.111
Surface application of paints using these compounds resulted in
an estimated 13.2 Mg (14.6 tons) of mercury emissions into the
atmosphere in 1990 and 4 Mg (5 tons) in 1991.
Mercury compounds are added to paints to preserve the paint
in the can by controlling microbial growth and to preserve the
paint film from mildew attack after it is applied to a surface.
During and after application of paint, these mercury compounds
-can be- emitted into the atmosphere. One source estimates that •
66 percent of the mercury used in paints is emitted into the
atmosphere; however, this emission rate, which Was derived using
engineering judgement, is based on a 1975 study performed when
8-8
-------
the demand for mercury in paint was high.10 The age of the data
and the method by which the emission factor was calculated limit
the reliability of the factor, making emission estimates
generated from it quite uncertain. Furthermore, no conclusive
information is available regarding the time frame over which
mercury in paint is emitted into the atmosphere -after it is
applied to a surface. However, limited information suggests that
emissions could occur for as long as 7 years after initial
application, although the distribution of emissions over this
time period is unknown.112
As of May 1991, all registrations for mercury biocides used
in paints were voluntarily canceled by the registrants, thus
causing a drastic decrease in the use of mercury in paint.113
For example, the paint industry's demand for mercury in 1989 was
192 Mg (211 tons) but fell to 6 Mg (7 tons) in 199I.100 Note
that emission estimates presume that all mercury emissions are
generated from.paint application in the year that the paint is
produced.
8.6 SOIL DUST
Mercury levels in soil dust have been measured at a few
locations in the western United States.94 The mercury level in
soil dust near a phosphate fertilizer operation in Pocatello,
Idaho was found to be 0.002 (20 ppm) weight percent and levels in
dust from an unpaved road near the same facility were at
0.001 weight percent. This reference also cited mercury levels
to be about 0.001 weight percent in soil dust near a courthouse
in Medford, Oregon; at a school in Bend, Oregon; near the
downtown area of Grant's Pass, Oregon; and near Key Back in
Eugene, Oregon. Samples taken near a silicone manufacturing
plant in Springfield, Oregon, showed mercury "levels at
0.004 weight percent in the soil dust. Tests at LaGrande dock in
LaGrande, Oregon, showed mercury in the soil"dust it levels of
0.003 weight percent.
8-9
-------
The validity of these levels cannot be verified because the
original, references could not be located to evaluate the test
methods and procedures used in these studies. In addition, the
mercury levels found in the soils of these areas probably are not
indicative of soil levels in other areas of the country. The
soils in the Idaho and Oregon areas are primarily volcanic in
geologic origin and have higher soil mercury levels than other
areas of the U.S.
8.7 NATURAL SOURCES OF MERCURY EMISSIONS
Mercury is emitted from natural sources (rock, soils, water
and biota) primarily as elemental mercury vapor and to a lesser
degree as particulate and vaporous oxides, sulfides and halides
of mercury. Organomercurie compounds (methylmercury vapors) are
also a significant component of natural emissions (some evidence
of dimethyl-mercury emissions also exists).114 However, few
direct .measurements of mercury flux and. speciation from natural
sources are available in the literature. There is general
agreement that the principal natural sources of mercury emissions
include, in order of probable importance, volatilization in
marine and other aquatic environments, volatilization from
vegetation, degassing of geologic materials, particulate matter
(PM) and vapor emissions during volcanic and geothermal activity,
wind-blown dust, and PM and vapor emissions during forest and
brush fires. Recent studies strongly emphasize the importance of
the air-water exchange of mercury as well as biologically
mediated volatilization in both marine and terrestrial
environments.114"11 These sources represent a relatively
constant flux to the atmosphere and may comprise 30 to 50 percent
of total natural emissions.117 In contrast, volcanic,
geothermal, and burning biomass activities are widely variable
temporally and spatially. Volcanic eruptions; in particular, can
cause massive perturbations in atmospheric -trace metal cycles.
Volcanic activity alone may comprise 40 to 50 percent of "total -
natural mercury emissions at times.117
8-10
-------
Published estimates of total global emissions of mercury
from natural sources range widely from 100 to 30,000 megagrams
(Mg) (110 to 33,000 tons) per year. However, the more recent
estimates cluster in the 2,000 to 3,000 Mg per year range.114"117
Lindqvist, citing work done in 1988, estimated natural emissions
to be 3,000 Mg (3,300 tons) per year or approximately 40 percent
of total global emissions from all sources.114 The supporting
data for individual source categories are limited for each of
these estimates, and it is clear that any quantitative
understanding of natural mercury flux is lacking.
As a result of reemission, current levels of mercury emitted
to the atmosphere by natural processes are elevated relative to
preindustrial levels. More than two thirds of world mercury
production has occurred since 1900, and mercury emissions have
been widely dispersed and recycled. In other words, present day
emissions from natural sources are comprised of a yesterday's
anthropogenic emissions, in part. It is not possible to quantify
the contribution of recycled mercury to the natural emissions
estimates and, therefore, the estimates cited above must be
viewed with even greater uncertainty.
8-11
-------
SECTION 9
SOURCE TEST PROCEDURES
9.1 INTRODUCTION
A number of methods exist to determine mercury emissions
from stationary sources. Several EPA offices and some State
agencies have developed source specific or dedicated sampling
methods for Hg. Other industry sampling methods do exist, but
none of these methods have been validated and will not be
discussed in this section.
Subsequent parts of this section discuss EPA reference or
equivalent sampling methods for Hg. Sampling methods fall into
one of two categories: (1) dedicated Hg methods for specific
sources or, (2) multiple-metals sampling trains that include Hg
for multiple sources. Each category of methods will be
H o a r* -r- -i Vio/-1 H-i f f o van f a a am/->nrr ^Via mot-ViriHc! w-i "} 1 V>o /^ i ct/->naaaH ariH a
N^ttf M *•» ••• ^*t* *^%^ , *a*rt. ^B ^ *v «• ^««*^« ••• ** - _- - »»^^ AA^ w«* W »»k^0 »«**x^ - 1 •• ^ ^ ^ *^ ^1* -Hfl^ ** ** «IBK« tav ~— *^ , W«*VBB «M
citation provided for more detailed information about the
methods. A summary of methods is presented in Table 9-1.
Sampling methods included in this section were selected from
EPA reference methods, draft methods, or State methods. To be a
reference method, a sampling method must undergo a validation
process and be published. To qualify as an equivalent method,.a
sampling method must be demonstrated to the EPA Administrator,
under specific conditions, as an acceptable alternative to the
normally used reference'methods. Also included in this section
is a draft method, which is under development.
9-1
-------
TABLE 9-1. MERCURY SAMPLING METHODS
Method
EPA 101
EPA 101 A
EPA 102
EPA 29
(Draft)
SW-8460012
OSW-BIF
CARB 436
Filter
None
Glass fiber
(optional)
None
Quartz or glass
fiber
Quartz or glass
fiber
Quartz or glass
fiber
Quartz or glass
fiber
Impinger
3 XICI
1 X silica gel
1 X KMn04
2 X KMn04
1 X silica gel
3 XICI
1 X silica gel
1 X empty (optional)
2 X HN03/H202
1 X empty
2 X KMn04/H2SO4
1 X silica gel
1 X empty (optional)
2 X HNO3/H2O2
1 X empty
2 X KMnO4/H2S04
1 X silica gel
1 X empty
2 X HN03/H202
1 X empty
2 X KMn04/H2S04
1 X silica gel
1 X empty
2 X HN03/H202
2 X KMn04/H2S04
1 X silica gel
Range
0.5 to 1 20 //g Hg/ml
20-800 ng Hg/ml
0.5 to 1 20 fJQ Hg/ml
ngHg/ml to //g Hg/ml
ngHg/ml to //g Hg/ml
ngHg/ml to fJQ Hg/ml
ngHg/ml to ywg Hg/ml
Chemical interference
S02
Oxidizable organic matter,
Water vapor on
optical window
S02
None
None
None
None
Detection limit
Not listed
Not listed
Not listed
0.2 ng Hg/ml
0.2 ng Hg/ml
0.2 ng Hg/ml
0.2 ng Hg/ml
vo
I
to
-------
9.2 DEDICATED MERCURY SAMPLING METHODS
9.2.1 EPA Method 101-Determination of Particulate and Gaseous
Mercury Emissions from Chlor-Alkali Plants11^
This method applies to the determination of particulate and
gaseous Hg emissions from chlor-alkali plants and other sources
(as specified in the regulations), where the carrier-gas stream
in the duct or stack is principally air. Particulate and gaseous
Hg emissions are withdrawn isokinetically from the source and
collected in an acidic iodine monochloride (IC1) solution. The
Hg collected (in the mercuric form) is reduced to elemental Hg
and then aerated and precipitated from the solution into an
optical cell and measured by atomic absorption spectrophotometry
(AAS). A diagram of a sampling train typical of dedicated Hg
sampling trains is presented in Figure 9-1.
After initial dilution, the range of this method is 0.5 to
120 micrograms of Hg per milliliter (pig Hg/ml). The upper limit
can be extended by further dilution of the sample. The
sensitivity of this method depends on the selected
recorder/spectrophotometer combination.
Analytical interferences include SC^ which reduces IC1 and
causes premature depletion of the IC1 solution. Also,
concentrations of IC1 greater than 10"4 molar inhibit the
reduction of the Hg(II) ion in the aeration cell. Condensation
of water vapor on the optical cell windows of the AAS causes a
positive interference.
Estimates of precision and accuracy were based on
collaborative tests, wherein 13 laboratories performed duplicate
analyses on two Hg-containing samples from a chlor-alkali plant
and on one laboratory-prepared sample of known Hg concentration.
9-3
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THERMOMETER
PROBE
RE VERSE-TYPE
PITOTTUIE
CHECK VALVE
ORIFICE
MANOMETER
MAIN VALVE
AIR-TIGHTPUMP
VACUUM LINE
VACUUM GAUGE
DRY TEH METER
Figure 9-1. Typical dedicated mercury sampling train.
-------
The estimated within-laboratory and between-laboratory standard
deviations are 1.6 and 1.8 fig Hg/ml, respectively.
9.2.2 EPA Method IQlA-Determination of Particulate and Gaseous
Mercury Emissions from Sewage Sludge Incinerators11^
This method is similar to Method 101, except acidic
potassium permanganate (KMn04) solution is used for collection
instead of acidic IC1. This method applies to the determination
of particulate and gaseous Hg emissions from sewage sludge
incinerators and other sources as specified in the regulations.
Particulate and gaseous Hg emissions are withdrawn
isokinetically from the source and collected in acidic KMn04
solution. The Hg collected (in the mercuric form) is reduced to
elemental Hg, which is then aerated from the solution into an
optical cell and measured by AAS.
After initial dilution, the range of this method is 20 to
800 nanograms of Hg per milliliter (ng Hg/ml). The upper limit
can be extended by further dilution of the sample. The
Sensitivity of the method, depends on the selected
recorder/spectrophotometer combination.
Analytical interferences include excessive oxidizable
organic matter in the stack gas, which prematurely depletes the
KMn04 solution, and thereby prevents further collection of Hg.
Condensation of water vapor on the optical cell windows of the
AAS causes a positive interference.
Based on eight paired-train tests, the within-laboratory
standard deviation was estimated to be 4.8 ng Hg/ml in the
concentration range of 50 to 130 micrograms of Hg per cubic meter
Hg/m3).
9-5
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9.2.3 EPA Method 102-Determination of Particulate and Gaseous
Mercury Emissions from Chlor-Alkali Plants-Hydrogen
Streams120
Although similar to Method 101, Method 102 requires changes
to accommodate the sample being extracted from a hydrogen stream.
Sampling is conducted according to Method 101, except:
1. Operate only the vacuum pump during the test. The other
electrical equipment, e.g., heaters, fans, and timers, normally
are not essential to the success of a hydrogen stream test.
2. Calibrate the orifice meter at flow conditions that
simulate the conditions at the source as described in APTD-0576
(see Citation 9 in Section 10 of Method 101). Calibration should
either be done with hydrogen or with some other gas having a
similar Reynolds Number so that there is a similarity between the
Reynolds Numbers during calibration and during sampling.
9.3 MULTIPLE METALS SAMPLING TRAINS
9.3.1 Method 0012-Methodology for the Determination of Metals
Emissions in Exhaust Gases from Hazardous Waste
Incineration and Similar Combustion Sources121
Two other multiple metals sampling methods developed by EPA
exist that can be used to collect Hg. These methods are the
Methodology for the Determination of Metals Emissions in Exhaust
Gases from Hazardous Waste Incineration and Similar Combustion
Sources and EPA Method 29-Methodology for the Determination of
Metals Emissions in Exhaust Gases from Incineration and Similar
Combustion Sources (Draft).122'123 Both methods are virtually
identical to Method 0012 in sampling approach and analytical
requirements.
9-6
-------
This method was developed for the determination of a total
of 16 metals, including Hg, from stack emissions of hazardous
waste incinerators and similar combustion processes. Method 0012
allows for the determination of particulate emissions from these
sources; however, the filter heating/desiccation modifications to
the sample recovery and analysis procedures described in this
protocol for the purpose of determining particulate emissions may
potentially impact the front-half Hg determination. A diagram of
a sampling train typical of a multiple metals sampling train is
presented in Figure 9-2.
The stack sample is withdrawn isokinetically from the
source. Particulate emissions are collected in the probe and on
a heated filter; gaseous emissions are collected in a series of
moisture knockout traps, chilled impingers, and silica gel traps.
Of the four solution charged impingers, two contain an aqueous
solution of dilute nitric acid (HN03) combined with dilute
hydrogen peroxide (H202) and two contain acidic potassium
permanganate (KMnO4) solution. Materials collected in the
sampling train are digested with acid solutions using
conventional Parr® Bomb, or microwave digestion techniques to
dissolve inorganics and to remove organic constituents that may
create analytical interferences. As many as six separate samples
can be recovered from the sampling train. The HNO3/H2O2 impinger
solution, the acidic KMn04 impinger solution, the hydrochloric
acid (HC1) rinse solution, the acid probe rinse, the acetone
probe rinse, and digested filter solutions can be analyzed for Hg
by cold vapor atomic absorption spectroscopy (CVAAS). As few as
three sample fractions can be analyzed for Hg; the combined probe
rinse and filter, the combined HN03/H202 impinger solutions, and
the combined KMnO4 impinger and rinse solutions. The detection
limit for Hg by CVAAS is approximately 0.2 ng Hg/ml.
The corresponding in-stack method detection limit can be
calculated by using (1) the procedures described in this method,
(2) the analytical detection limits described in the previous
9-7
-------
Al gtMt MMfte AipoMd tuitao* to km.
|EM»pl Mtwn laftm HIM support to UMd).
vo
OD
Empty (OpteiMl MoUlw* Knockom)
6XHNO, /IOXH
4XKUnO4/IO*H28O4
Figure 9-2. Typical multiple metals sampling train.
-------
paragraph, (3) a volume of 300 ml for the front-half and 150 ml
for the back-half samples, and (4). a stack gas sample volume of
1.25 m3:
where: A = analytical detection limit, /*g Hg/ml
8* = volume of sample prior to aliquot for analysis, ml
C =» sample volume, dry standard cubic meter (dscm)
D = in- stack detection limit, /*g Hg/m3
The in- stack method detection limit for Hg using CVAAS based
on this equation is 0.07 /xg Hg/m3 for the total sampling train.
A similar determination using AAS is 5.6 /*g Hg/m3 .
•
9.3.2 GARB Method 436 -Determination of Multiple Metals Emissions
from Stationary Sources124
This method is applicable for determining the emissions of
metals, including Hg, from stationary sources. This method is
similar to SW-846 Method 0012 in sampling approach and analytical
requirements. Method 436 suggests that the concentrations of
target metals in the analytical solutions be at least 10 times
the analytical detection limits. This method may be used in lieu
of Air Resource Board Methods 12, 101, 104, 423, 424, and 433.
9.4 ANALYTICAL METHODS FOR DETERMINATION OF MERCURY125'126
This section contains brief descriptions of two analytical
techniques generally used for Hg determinations.
The two Hg analysis methods are Method 7470 and 7471, from
SW-846. Both methods are cold- vapor atomic absorption methods,
based on the absorption of radiation at the 253.7-nm wavelength
by mercury vapor. Mercury in the sample is reduced to the
elemental state and aerated from solution in a closed system.
9-9
-------
The Hg vapor passes through a cell -positioned in the light path
of an atomic absorption spectre-photometer. "Absorbance (peak
height) is measured as a function of mercury concentration.
Cold-Vapor AA (CVAA) uses a chemical reduction to selectively
reduce Hg. The procedure is extremely sensitive but is subject
to interferences from some volatile organics, chlorine, and
sulfur compounds. The typical detection limit for these methods
is 0.0002 mg/L.
The two methods differ in that Method 7470 is approved for
analysis of Hg in mobility-procedure extracts, aqueous wastes,
and ground waters. Method 7471 is approved for analysis of Hg in
soils, sediments, bottom deposits, and sludge-type materials.
Analysis of samples containing high amounts of organic present
•
special problems: (1) likely to foam during the reduction step
and block the flow of sample to the absorption cell and (2) have
high reducing capability and can reduce Hg(II) to Hg before
addition of stannous chloride (SnCl2).
Two analytical considerations are common to both methods.
stannous chloride should be added immediately prior to analysis
to ensure the reduction of Hg(II) to Hg occurs in the
vaporization cell only. Second, moisture in the absorption cell
can reduce the reliability of the method and should be eliminated
or minimized. Finally, a closed-loop system may provide a more
reliable system than an open-loop system for introduction of the
sample to the reaction flask.
9.5 SUMMARY
All of the above source sampling methods collect a sample
for analysis of multiple metals, including Hg, or a sample for Hg
analysis alone. Significant criteria and characteristics of each
method are presented in Table 9-1. This table is a summary of
information presented in various methods. The major differences
between the methods involve: (1) the type of impinger solutions,
9-10
-------
(2) the amount or concentration of impinger solutions, (3) the
sequence and types of sample train recovery solutions, and
(4) the use and/or type of particulate filter.
In assessing Hg emissions from test reports, the age or
revision number of the method indicates the level of precision
and accuracy of the method. Older methods are sometimes less
precise or accurate than those that have undergone more extensive
validation. Currently, EPA Method 301 from 40 CFR Part 63,
Appendix A can be used to validate or prove the equivalency of
new methods.
9-11
-------
SECTION 10
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87. Woodbury, W. D. Lead-Annual Report 1990. Bureau of Mines,
U. S. Department of the Interior, U. S. Government Printing
Office, Washington, D.C. April 1992.
88. Facsimile from Richardson, J., ASARCO, Inc., Salt Lake
City, Utah, to Midwest Research Institute. August 24,
1993. Primary lead smelting process information and
mercury emission factors.
89." Facsimile from Jolly, J., Bureau of Mines, U.S. Department
of the Interior, Washington, DC., to Midwest Research
Institute. January 23, 1993. Capacities of U.S. Copper
Smelters.
90. TRC Environmental Corporation. Emission Characterization
Program. Prepared for Copper Range Company, White Pine,
Michioan. Orhoh^r 15. 1QQ2.
— ^ , _____ , .. _ _ .
91. United States Refining Capacity. National Petroleum
Refiners Association. Washington, D.C. January 1, 1992.
Pp 31-34.
92. Rucker, J. E., and R. P. Streiter. Section 17. The
Petroleum Industry. Air Pollution Engineering Manual. Air
and Waste Management Association, Pittsburgh, PA.
93. Shreve, R. N., and J. A. Brink, Jr. Chemical Process
Industries. New York. McGraw-Hill Book Company. 1977.
94. SPECIATE. Volatile Organic Compound (VOC)/Particulate
Matter (PM) Speciation Data System, Version 1.4. Office of
Air and Radiation,. Office of Air Quality Planning and
Standards, U. S. Environmental Protection Agency, Research
Triangle Park, NC. October 1991.
10-9
-------
95. AB2588 Pooled Source Emission Test Program, The Almega
Corporation Project 16551, The Almega Corporation Report
16551-4. Volume I. Prepared for Western States Petroleum
Association, Glendale, Ca. July 1990.
96. Dickson, P. F. Oil Shale. (In) Kirk-Othmer Concise
Encyclopedia of Chemical Technology. 3rd ed. M. Grayson,
executive ed. A Wiley-Interscience Publication, John Wiley
and Sons, New York, NY. 1985.
97. Emission Standards and Engineering Division. Source
Category Survey: Oil Shale Industry. EPA-450/3-81-010.
Office of Air, Noise, and Radiation, Office of Air Quality
Planning and Standards, U.S. Environmental Protection
Agency, Research Triangle Park, North Carolina.
August 1981.
98. Robertson, D. E., E. A. Crecelius, J. S. Fruchter, and
J. D. Ludwick. Mercury. Emissions from Geothermal Power
Plants. Science, 196(4294): 1094-1097. 1977.
99. Facsimile. Marshal, R., Department of Energy, Geothermal
Division, to Campbell, T., Midwest Research Institute.
Location and capacity information on U.S. geothermal power
plants. February 1993.
100. Bureau of Mines, Division of Mineral Commodities, U. S.
Department of- the Interior, Washington DC. Mercury
Statistics. 1991
101. Lowenheim, F. A., and M. K. Moran. Vinyl Chloride. (In)
Faith, Keyes, and Clark's Industrial Chemicals. 4th ed.
Wiley-Interscience Publication, John Wiley and Sons, New
York, NY. 1975.
102. A. D. Little, Inc. Exposure and Risk Assessment for
Mercury. EPA Contract 68-01-3957. U. S. Environmental
Protection Agency. 1980.
103. Motor Vehicle Manufacturers Association (MVMA). MVMA Motor
Vehicle Facts and Figures '92. Motor Vehicle Manufacturers
Association, Detroit, Michigan.
\
104. Pierson, W. R., and W. W. Brachaczek. Particulate Matter
Associated with Vehicles on the Road. II. Aerosol Science
and Technology 2:1-40 (1983).
105. Urban, C.M. and R.J. Garbe. Regulated and Unregulated
Exhaust Emissions from Malfunctioning Automobiles.
Presented at the Society of Automotive Engineers (SAE)
Passenger Car Meeting, Dearborn, Michigan. June 1979.
10-10
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106. Warner-Selph, M.A. and J. DeVita. Measurements of"Toxic
Exhaust Emissions from Gasoline-Powered Light-Duty
Vehicles. Presented at the Society of Automotive Engineers
(SAE) International Fuels and Lubricants Meeting and
Exposition, Baltimore, Maryland. September 1989.
107. Personal communication. M.A. Warner-Selph, U. S.
Environmental Protection Agency, Office of Air Quality
Planning and Standards with T. Lapp, Midwest Research
Institute. Analytical ^detection limits for mercury in the
1989 study. April 1993.
108. Cremation Association of North American (CANA). Cremation
Statistics from Cremationist Journal. Compiled by CANA.
1992.
109. Facsimile, Springer, J., Cremation Association of North
American, to T. Campbell, Midwest Research Institute.
Number of Crematories by State, 1991. February 1993.
110. Vander Most, P.F.J. and C. Veldt. Emission Factors Manual:
Emission Factors for Air Pollutants 1992. Report Reference
Number 92-235. TNO Environmental and Energy Research, The
Netherlands. September 1992.
111. U. S. Environmental Protection Agency, Office of Pesticide
Programs. Environmental Fact Sheet-Mercury Biocides in
Paint. July 1990.
112. U. S. Environmental Protection Agency, Office of Solid
Waste. Characterization of Products Containing Mercury in
Municipal Solid Waste in the United States, 1970 to 2000.
April 1992.
113. Agocs, M. M., et al. Mercury Exposure from Interior Latex
Paint. The New England Journal of Medicine. October 18,
1990. pp. 1096-1101.
114. Lindqvist, 0., K. Johansson, M. Aatrup, A. Andersson,
L. Bringmark, G. Hovsenius, L. Hakanson, A. Iverfeldt,
M. Meili, and B. Timm. Mercury in the Swedish Environment:
Recent Research on .Causes, Consequences and Corrective
Methods. Water Air Soil Pollut. 55(1-2): 26-30, 38-39,
65-70. 1991.
115. Environmental Health Criteria 1. Mercury. World Health
Organization. Geneva. 1976.
116. Klein, D. H. Some Estimates of Natural Levels of Mercury
in the Environment. In: Environmental Mercury
Contamination, R. Hartung and B. D. Dinman, eds. Ann Arbor-
Science Publishers, Inc. Ann Arbor, Michigan. 1972.
10-11
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117. Nriagu, J. O. A Global Assessment of Natural Sources of
Atmospheric Trace Metals. Nature. Vol. 338. March 2,
1989.
118. EPA Method 101, Determination of Particulate and Gaseous
Mercury Emissions from Chlor-Alkali Plants. 40 Code of
Federal Regulations, Part 61, Appendix B. Washington, B.C.
U.S. Government Printing Office. 1992.
119. EPA Method 103A, Determination of Particulate and Gaseous
Mercury Emissions from Sewage Sludge Incineration. 40 Code
of Federal Regulations, Part 61, Appendix B. Washington,
D.C. U.S. Government Printing Office. 1992.
120. EPA Method 102, Determination of Particulate and Gaseous
Mercury Emissions from Chlor-Alkali Plants - Hydrogen
Streams. 40 Code of Federal Regulations, Part 61,
Appendix B. Washington, D.C. U.S. Government Printing
Office. 1992.
121. EPA Method 0012, Methodology for the Determination of
Metals Emissions in Exhaust Gases from Hazardous Waste
Incineration and Similar Combustion Sources, Test Methods
for Evaluating Solid Waste; Physical/Chemical Methods.
SW-846, Third Edition. Office of Solid Waste and Emergency
Response. U. S. Environmental Protection Agency,
Washington, D.C. September 1988.
122. Methodology for the Determination of Metals Emissions in
Exhaust Gases from Hazardous Waste Incineration and Similar
Combustion Sources, Methods Manual for Compliance with the
BIF Regulations Burning Hazardous Waste in Boilers and
Industrial Furnaces. E.P.A./530-SW-91-010. Office of Solid
Waste and Emergency Response. U.S. Environmental
Protection Agency, Washington, D.C. December 1990.
123. EPA Method 29, Methodology for the Determination of Metals
Emissions in Exhaust Gases from Incineration and Similar
Combustion Sources (Draft). 40 Code of Federal
Regulations, Part 60, Appendix A. Washington, D.C. 1992.
124. CARB Method 436, Determination of Multiple Metals Emissions
from Stationary Sources. State of California Air Resources
Board, Sacramento, CA.
125. EPA.Method 7470, Mercury in Solid or Semisolid Waste
(Manual Cold-Vapor Technique), Test Methods for Evaluating
; Solid Waste; Physical/Chemical Methods. SW> 8.46;.. Third;
Edition. Office of Solid Waste and Emergency Response.
U. S. Environmental Protection Agency, Washington, D.C.
September 1988. ' :
10-12
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126. EPA Method 7471, Mercury in Solid or Semisolid Waste
(Manual Cold-Vapor Technique), Test Methods for Evaluating
Solid Waste; Physical/Chemical Methods. SW-846, Third
Edition. Office of Solid Waste and Emergency Response.
U. S. Environmental Protection Agency, Washington, D.C.
September 1988.
10-13
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APPENDIX A.
NATIONWIDE EMISSION ESTIMATES
-------
EMISSIONS FROM MERCURY PRODUCTION
Secondary Mercury Production
Basis of Input Data
1. Emission factor of 20 kg of Hg/Mg Hg produced.1
2. 1990 production from industrial and governmental
sources was 286 Mg.2
3. Emissions from secondary mercury production are
uncontrolled.
4. Emissions due to chemical and thermal treatment are
equal.
Calculation
Annual emission = 20 kg/Mg * 286 Mg = 5.7 Mg/yr =
6.3 tons/yr
A-l
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EMISSIONS FROM MAJOR USES OF MERCURY • '"
Chior-Alkali Production
Basis of Input Data.
1. In 1990 TRI summary, 17 of the 18 mercury cell
facilities reported air emissions of mercury.
2. -The total quantity of mercury emissions from
17 facilities was 8.74 Mg (9.6 tons).
3. Emission data were prorated for the remaining facility.
Calculation
Annual emissions = 18/17 * 8.74 Mg/yr =9.3 Mg/yr =
10.2 tons/yr
Battery Manufacture
Basis of Input Data
1. The 1990 consumption of mercury in the production of
primary batteries was 106 Mg (117 tons).
2. A mercury emission factor of 1.0 kg/Mg used
(2.0 Ib/ton) was obtained from a Wisconsin study of a
mercury oxide battery plant, which is the only type of
battery using mercury.
3. Another mercury emission factor of 5.6 kg/Mg
(11.2 Ib/ton) has been cited but the source and
reliability of this factor could not be verified.5
4. The emission factor based on TRI data may give
abnormally high values because the TRI data includes
abnormal and accidental releases.
Calculation
Wisconsin study --
Annual emissions =1.0 kg/Mg * 106 Mg = 106 kg/yr =
0.11 Mg/yr =0.12 ton/yr
A-2
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Electrical Uses
Electric lighting --
Basis of Input Data
1. The 1990 consumption of mercury was 33 Mg (36 tons).^
2. No emission factor is available for the manufacture of
electric lamps.
3. The only mercury emission information available is due
to lamp breakage of outdoor and indoor lamps.
4. It is assumed that 50 percent of the mercury used in
lamps was for outdoor lamps and 50 percent for indoor
lamps.
5. Of the mercury used in outdoor lamps, 33 percent will
be released to the atmosphere and 22 percent from the
indoor lamps.1
Calculation
Outdoor lamps - -
Annual emission = 33 Mg * 0.5 * 0.33 = 5.4 Mg/yr =
6.0 tons/yr
Indoor lamps
Annual emissions = 33 Mg * 0.5 * 0.22 = 3.6 Mg/yr =
4 tons/yr
EMISSIONS FROM COMBUSTION SOURCES
Coal Combustion
Coal-Fired Utility Boilers--
Basis of Input Data
1. From Table 6-8, emission factor for bituminous coal
• combustion = 7.0 x 10~15 kg/J and for anthracite coal
combustion = 7.6 x 10~15 kg/J.
2. Bituminous coal combustion systems controlled by ESP's
with an average mercury control efficiency of
25 percent.
3. Anthracite coal combustion systems uncontrolled.
A-3
-------
4. Energy from coal combustion in utility sector from
Table 6-1.
Calculations
Annual Emissions = 7.0 x 10~15 kg/J * 16.939 x 1018 J/yr *
0.75
+ 7.6 x 10"15 kg/J * 0.018 x 1018 J/yr
•=89.07 Mg/yr = 97.98 tons/yr
Coal-Fired Industrial Boilers--
Basis of Input Data
1. From Table 6-8, emission factor for bituminous coal
combustion = 7.0 x 10"15^ kg/J and for anthracite coal
combustion = 7.6 x 10~15 kg/J
2. No control of emissions from industrial boilers was
assumed.
3. Energy from coal combustion in industrial sector from
Table 6-1.
Calculations
Annual Emissions = 7.0 x 10~15 kg/J * 2.892 x 1018 J/yr
+ 7.6 x 10~15 kg/J * 0.009 x 1018 J/yr
= 20.31 Mg/yr = 22.34 ton/yr
Coal-Fired Commercial and Residential Boilers- -
Basis of Input Data
1. From Table 6-8, emission factor for bituminous coal
combustion = 7.0 x 10"^ kg/J and for anthracite coal
combustion = 7.6 x 10~15 kg/J
2. No control of emissions from commercial/residential
boilers was assumed.
3. Energy from coal combustion in commercial/residential
sectors from Table 6-1.
Calculations
Annual Emissions = 7.0 x 10"15kg/J * 0.130 x 1018 J/yr
+ 7.6 x 10"15kg/J * 0.032 x 1018J/yr
=1.15 Mg/yr =1.27 tons/yr
A-4
-------
Oil Combusion
Oil-Fired Utility Boilers--
Basis of Input Data.
1. From Table 6-15, emission factor for distillate oil
combustion = 2.9 x 10"^ kg/J and for residual oil
combustion = 3.0 x 10~15 kg/J
2. Air pollution control measures assumed to provide no
mercury emission reduction.
3. Energy consumption from fuel oil combustion from
Table 6-1.
Calculations
Annual Emissions = 2.9 x 10~15 kg/J * 1.201 x 1018 J/yr
+ 3.0 x 10'15 kg/J * 0.091 x 1018 J/yr
=3.76 Mg/yr =4.14 tons/yr
Oil-Fired Industrial Boilers--
Basis of Input Data
1. . From Table 6-15, emission factor for distillate oil
combustion = 2.9 x 10~15 kg/J and for residual oil
combustion = 3.0 x 10~15 kg/J
2. Air pollution control measures assumed to provide no
mercury emission reduction.
3. Energy consumption from fuel oil combustion from
Table 6-1.
Calculations
Annual Emissions = 2.9 x 10~15 kg/J * 1.245 x 1018 J/yr
+ 3.0 x 10~1S kg/J * 0.436 x 1018 J/yr
=4.92 Mg/yr =5.42 tons/yr
Oil-Fired Commercial/Residential Boilers--
Basis of Input Data
1. From Table 6-15, emission factor for distillate oil
combustion = 2.9 x lO"1^ kg/J and for residual oil
combustion = 3.0 x 10~15 kg/J
2. Air pollution control measures assumed to provide no
mercury emission reduction.
A-5
-------
3. Energy consumption from fuel oil combustion from
Table 6-1.
Calculations
Annual Emissions = 2.9 x 10"15 kg/J * 1.395 * 1018 J/yr
+ 3.0 x 10'15 kg/J * 0.255 x 1018 J/yr
- 4.81 Mg - 5.30 tons/yr
Wood .Combustion in Boilers--
Basis of Input Data
1. Wood combustion rate in boilers is 1.0 x 1011 Btu/hr,
which is the same rate as 1980 given on p. 6-37.
Boilers assumed to operate at capacity, 8,760 hr/yr.
2. Heating value of wood is 4,500 Btu/lb based on midpoint
of range presented on p. 6-37.
.3. Emission factor of 6.5 x 10"6 Ib/ton of wood burned.
4. No control of mercury emissions.
Calculations
Annual Emissions
= 1.0 x 1011 Btu/hr * 8.760 hr/vr * 6.5 x 10'6 Ib/tons wood
4,500 Btu/lb * 2,000 Ib wood/ton wood * 2,000 Ib Hg/ton Hg
= 0.32 ton/yr = 0.29 Mg/yr
Municipal Waste Combustors--
Basis of Input Data
1. Under the assumption that ESP's provide essentially no
control, the facility-average concentrations at
7 percent oxygen for uncontrolled and ESP-controlled
mass burn (including modular) and RDF systems contained
in Table B-2 were averaged to obtain the following
"typical" concentrations:
Mass Burn - 696 /xg/dscm
RDF - 561 /zg/dscm
2. The F-factor for municipal waste combustors was assumed
to be 0.257 x 10"6 dscm/J at 0 percent oxygen and the
heating values were assumed to be 4,500 Btu/lb for MSW
and 5,500 Btu/lb for RDF (see p. 6-53). The F-factor
was converted from 0 percent oxygen to 7 percent oxygen
A-6
-------
(at which concentrations are based) using a factor of
1.5.
3. Based on a meeting with the EPA MWC project team, all
modular MWC's are assumed to be controlled with ESP's.
4. Spray dryer or duct sorbent injection systems combined
with fabric filters or ESP's and wet scrubber systems
achieve 50 percent" removal. No other control measures
achieve appreciable mercury control.
5. The 1990 MWC processing rates are assumed to be equal
to those presented in Waste Age. November 1991, and
tabulated in the calculation table below.6
Calculations
Uncontrolled Emission Factors
• Mass burn/modular - 670 ^g/dson * 0.257 x 10"^ dscm/J *
10,500 J/g * 1.5 = 2.71 g/Mg
• RDF - 527 /xg/dscm * 0.257 x 10'6 dscm/J * 12,800 J/g *
1.5 = 2.60 g/Mg
Controlled Emissions
Annual Emissions
= Process rate * emission factor * (100-efficiency)
100
The calculated emissions are tabulated below:
Combust or
type
Mass Burn
Mass Burn
Mass Burn
Mass Burn
RDF
Modular
Total
Control
status3
U
SD
DSI
ESP
SO
ESP
Process
rate,
10° Mg/yr
0.517
7.190
1.077
13.806
2.809
0.630
Uncontrolled
emission
factor, g/Mg
2.8
2.8
2.8
2.8
2.8
2.8
Control
efficiency,
X
0
50
50
0
50
0
Annual Emissions
Mg/yr
1.45
10.07
1.51
38.66
3.93
2.25
57.87
ton/yr
1.60
11.10
1.66
42.61
4.34
2.48
63.79
aSD = Spray dryer with either ESP or fabric filter
ESP = Electrostatic precipitator - "..-.--
DSI = Duct sorbent injection with either ESP or fabric filter
U = Uncontrolled
A-7
-------
Sewage Sludge Incinerators --
Basis for Input Data
1. Total sludge processed annually is 1.5 x 106 Mg
(see p. 6-54)
2. From the Draft AP-42, Section 2.5, Sewage Sludge
Incineration, an average emission factor for units with
a venturi control device was 0.018 g/Mg
(3.5 x 10"5 lb/ton).7 .For other control devices, the
average emission factor was 1.6 g/Mg
(3.2 x 10~3 lb/ton).
3. In the U.S., there are 210 sewage sludge incinerators;
of this population, 47 use venturi control devices,
97 use other control devices, and no information was
available for 66 units.8 Of the 144 units for which
data are available, 47/144 or 33 percent use venturi
controls and 97/144 or 67 percent use other controls.
This percentage distribution is assumed to be
representative for all 210 units.
Calculations
Annual Emissions = 1.5 x 10^ Mg/yr * 0.33 * 0.018 g/Mg +
1.5 x 106 x 0.67 x 1.6 g/Mg =1.62 Mg/yr
= 1.79 tons/yr
Medical Waste Incinerators - -
Basis of Input Data
1. The annual emission estimates are based on a model
plant calculation procedure employed in developing the
environmental impacts for the New Source Performance
Standard for medical waste incinerators.9 Uncontrolled
Hg concentrations are assumed to be 3,100 /tg/dscm at
7 percent 02 for continuous and intermittent MWI's,
2,300 jtg/dscm at 7 percent 02 for batch MWI's, and
50 /*g/dscm at 7 percent 02 for pathological MWI's.
2. No appreciable control of Hg emissions is achieved by
existing facilities.
A-8
-------
3.
The operating characteristics and numbers of units
associated with existing MWI's are:
Model
No.
1
2
3
4
5
6
7
Type
Continuous
Continuous
Intermittent
Intermittent
Intermittent
Batch
Pathological
Flow rate, dscfm
at 14% O2
4,747
3,165
4,747
1,899
633
455
730
Operating
hours, hr/yr
7,760
3,564
4,212
4,212
3,588
3,520
2,964
No. of units
154
182
171
742
2,097
335
1,305
Calculations
1. Example for Model 1
Annual emissions
- 154 units « 7'760hl . 60min . 4-747 £fc3
unityl hi """
= 14.94 Mg/yr = 16.47 ton/yr
2. Total emissions
Annual emissions
1 m3
35.31 ft3
3,100 tig
mj
emissions for Model i
«i
= 14.94 + 5.41 + 9.01 + 15.63 + 12.55 + 1.05 + 0.12
=58.7 Mg/yr =64.7 tons/yr
EMISSIONS FROM MISCELLANEOUS MANUFACTURING PROCESSES
Portland Cement Production
Basis of Input Data
1. The 1990 total production of cement was 70.6 x 106 Mg
(77.8 x 106 tons) of which 95.7 percent was portland
cement. Total production of portland cement was
67.5 x 106Mg (74.5 x 106 tons).2 Portland cement is
•96% clinker.
A-9
-------
2. From Table C-2, the average emission factor is
8.7 x 10'2 g/Mg (1.7 x 10"4 Ib/ton) of clinker
produced. This emission factor is based on the average
of all test runs in Table C-2.
Calculations
Annual emissions:
67.5 x 106 Mg * 8.7 x 10~2 g/Mg * 0.96 = 5.6 Mg/yr =
6.2 tons/yr
Lime Manufacture
Basis of Input Data
1. Based on the total production of lime in 1989 and 1992
cited in the discussion of Lime Manufacturing (see
p. 7-8), the estimated 1990 total production of lime
was 15.6 x 106 Mg (17.2 x 106 tons)
2. An emission factor of 5.5 x 10"2 g/Mg of lime produced
(1.1 x 10"4 Ib/ton) is used. This figure is based on a
study of mercury emissions from five kilns in Wisconsin
and kiln production quantities cited on p. 7-13. ^
3. Natural gas, which contains no mercury, is used to fire
33 percent of the lime kilns and thus would result in
no mercury emissions from the fuel source.
Calculations
Annual emissions:
15.6 x 106 Mg * 5.5 x 10"2 g/Mg * 0.67 » 0.57 Mg/yr =
0.63 tons/yr
Carbon Black Production
Basis of Input Data
1. The 1990 total capacity for carbon black production was
1.47 x 106 Mg (1.62 x 106 tons).11 No data were
available for actual production of carbon black in
1990.
2. An emission factor of 1.5 x 10"4 kg of Hg/Mg of carbon
black (3 x 10 "4 Ib/ton) is used.12
3. The emission factor is based only on the oil-furnace
process which accounts for 99 percent of all carbon
black production.
A-10
-------
4. Mercury emissions are based on production capacity and
not actual production. Use of actual production data
would show a lower value for mercury emissions.
Calculations
Annual emissions = 1.5 x 10"4 kg/Mg * 1.47 x 106 Mg =
0.22 Mg/yr =0.24 ton/yr
Byproduct Coke Production
No emission factors are available for mercury emissions from
this process.
Primary Lead Smelting
Basis of input Data
1. Based on background information in the NSPS for lead
smelters, 100 units of ore yields 10 units of ore
concentrate, 9 units of sinter, and 4.5 units of
refined lead.1^
ore -*> ore concentrate •* sinter -» refined lead
100 units 10 units 9 units 4.5 units
2. Using 1989 lead ore consumption levels with previous
years data, the estimated 1990 lead ore utilization
quantity was 3.74 x 10° Mg -(4.11 x 10° tons) .
3. The mercury emission factors from Table 7-5 for five
emission sources in the process are:
a. materials handling: ore crushing = 0.0012 kg/Mg
(0.0024 Ib/ton) of raw material
b. materials handling: sinter charge
mixing = 0.0065 kg/Mg (0.013 Ib/ton) of ore
concentrate
c. sinter machine leaks = 0.0007 kg/Mg
(0.0014 Ib/ton) of sinter
d. blast furnace - 0.0019 kg/Mg (0.0038 Ib/ton) of
ore concentrate
e. slag furnace + slag pouring = 0.0021 kg/Mg
(0.0042 Ib/ton) of lead product
A-11
-------
Calculations
Annual emission from material handling (ore crushing):
0.0012 kg/Mg * 3.74 x 106 Mg = 4.5 Mg/yr =5.0 tons/yr
Annual emission from material handling (sinter charge
mixing): 0.0065 kg/Mg * 3.74 x 10s Mg = 2.4 Mg/yr =
2.6 tons/yr
Annual emissions from sintering:
0.0007 kg/Mg * 3.36 x 10s Mg = 0.24 Mg/yr =0.26 tons/yr
Annual emission from blast furnace:
0.0019 kg/Mg * 3.74 x 10s Mg = 0.71 Mg/yr =0.78 tons/yr
Annual emissions from slag furnace + slag pouring:
0.0021 kg/Mg * 1.87 x 105 Mg = 0.39 Mg/yr =0.43 tons/yr
Total annual emissions:
4.5 Mg/yr +2.4 Mg/yr +0.24 Mg/yr +0.71 Mg/yr +0.39 Mg/yr
8.2 Mg/yr » 9.0 tons/yr
Petroleum Refining
A mercury emission factor for the fluid caking unit in the
conversion step was obtained from SPECIATE but the original
references could not be obtained to confirm the emission data.
Therefore, the data from SPECIATE were judged unacceptable for
use. Mercury emission data were obtained from the CARB Air
Toxics Emission Inventory Report for selected processes in
petroleum refining using refinery gas as the fuel. No data could
be located for the nationwide volume of refining gas used for
these selected processes. Therefore, no mercury emissions could
be calculated for the petroleum refining industry.
Oil Shale Retorting
Because there are no commercial oil shale retort facilities
in operation in the U.S., a mercury emission value of zero has
been assumed.
Geothermal Power Plants- -
Basis of Input Data
1. Only three States report production of electric power
by geothermal.means, California, Nevada, and Utah.
2. A mercury emission factor, based on a 1977 report, was"
stated to be 0.05 g/MW-hr from the cooling tower
exhaust and 0.0073 g/MW-hr from the off-gas ejectors.14
A-12
-------
3. It was assumed that the net capacity of the gee-thermal
power plants stated in Table 7-8 was valid for 1990.
4. It was assumed that the mercury emission factors
developed in 1977 for the California power facility are
valid for all California, Nevada, and Utah facilities
in 1990.
5. It was assumed that geothermal power plants operate
24 hr/d, 365 d/yr (8,760 hr/yr). %
Calculations
Off-gas ejectors: 8,760 hr/yr * 0.0073 g/MW-hr *
. 2,628.4 MW/yr = 0.17 x 106 g/yr =0.17 Mg/yr
Cooling tower exhaust: 8.760 hr/yr * 0.05 g/MW-hr *
2,628.4 MW/yr - 1.15 x 106 g/yr -1.15 Mg/yr
Total annual emissions = 0.17 Mg/yr + 1.15 Mg/yr =
1.3 Mg/yr = 1.4 tons/yr
EMISSIONS FROM MISCELLANEOUS FUGITIVE AND AREA SOURCES
Mercury Catalysts
There is only one facility in the U.S. that may be using
small quantities of mercury catalysts. Because no emission
factors are available and only one facility, zero emissions have
been assumed.
Dental Alloys
Basis for Input Data
l. In 1990, the total usage of mercury in dental equipment
and supplies was 27 Mg (30 tons).
2. It has been -estimated that 2 percent of the mercury
used in dental applications is emitted to the
atmosphere.1 This figure would correspond to an
emission factor of 20 kg/Mg (40 Ib/ton) of mercury
used.
3. This emission factor is .based on information
approximately 15 years old so it should be viewed with
caution because dental practices have changed
considerably in the interim.
A-13
-------
Calculation
Annual emissions = 20 kg/Mg * 27 Mg = 0.54 Mg/yr =
0.59 ton/yr
Mobile Sources
Basis for Input Data
1. An emission factor of 1.3 x 10 "^ mg/km traveled
(4.6 x 10"9 Ib/mile) was obtained from a 1983 study.15
2. This emission factor should be interpreted with caution
since it was based on a 1977. ambient sampling study,
which was before the use of catalytic converters,
unleaded gasoline, and state-regulated I/M programs.
3. In 1990, the total miles traveled in the U.S was
2,147,501 million miles (3,457,478 x 10s km).16
Calculation • •
Annual emissions = 3.4575 x 1012 km * 1.3 x 10"3 mg/km =
4.5 x 109 mg = 4.5 Mg/yr = 5 tons\yr
Crematories
Basis for Input Data
1. In 1991, there were 400,500 crematories in the U.S.17
2. No data are available for the average quantity of
mercury emitted for a cremation in the U.S. An
estimated emission of 1 g of mercury per cremation has
been recommended as a typical value in Europe. ° This
emission factor will be used for estimations for the
U.S.
3. There is a considerable variation in the overall dental
care programs between the U.S. and Europe which may
result in differences in the average number of mercury
amalgam fillings per person.
Calculations
Annual emissions:
400,500 cremations * 1 g/cremation =0.4 Mg/yr = 0.44 ton/yr
A-14
-------
Paint Application
Basis for Input Data
1. In 1990, the total usage of mercury in paints was 20 Mg
(22 tons).2
2. It is estimated that 66 percent of the mercury used in
paints is emitted into the atmosphere.1^
3. This estimate presumes that all mercury emissions are
generated from paint application in the year that the
paint is produced.
Calculation
Annual emissions:
20 Mg * 0.66 = 13.2 Mg = 14.6 tons/yr
A-15
-------
TABLE A-l. SUMMARY OF MERCURY EMISSION FACTORS AND SCC
SCC number
3-03-999-99
3-04-999-99
3-99-999-94
1-01-001
1-01-002
1-02-001
1-02-002
1-03-001
1-03-002
1-01-004
1-01-005
1-02-004
1-02-005
1-03-004
1-03-005
1-02-009
5-01-001-02
5-01-001-02
5-01-001-03
5-O1-O01
5-01-005-15
5-01-005-16
5-01-005-16
Source description
Primary mercury production
Secondary mercury production
Battery manufacture
(mercuric oxide)
Coal combustion: Utility boilers
Coal combustion: Utility boilers
Coal combustion: Industrial boilers
Coal combustion: Industrial boilers
Coal combustion: Commercial &
residential
Coal combustion: Commercial &
residential
Oil combustion: Utility boilers
Oil combustion: Utility boilers
Oil combustion: Industrial boilers
Oil combustion: Industrial boilers
Oil combustion: Commercial &
residential
Oil combustion: Commercial &
residential
Wood combustion: Boilers
Municipal waste combustors: Mass
burn
Municipal waste combustors: Mass
bum
Municipal waste combustors: RDF
Municipal waste combustors:
Modular
Sewage sludge incinerators
Sewage sludge incinerators
Sewage sludge incinerators
Control
status3
C
U
u
U
u
u
u
u
u
u
u
u
u
u
u
u
u
C
C
u
C
u
C
Mercury emission factor
0. 13 kg/Mg produced
20 kg/Mg produced
1.0 kg/Mg used
7.6x 10' 15kg/J produced
7.0xlO'15 kg/J produced
7.6xlO'15 kg/J produced
7.0xlO'15Mg/J produced
7.6xlO'15 kg/J produced
7.0xlO'15 kg/J produced
3.0xlO'15 kg/J produced
2.9xlO'15 kg/J produced
3.0xW15 kg/J produced
2.9xlO'15 kg/J produced
3. Ox 10' 15 kg/J produced
2.9xlO'15 kg/J produced
3.4X1Q-6 kg/Mg burned
2.8 g/Mg waste
1.4 g/Mg waste
1.4 g/Mg waste
2.8 g/Mg waste
0.018 g/Mg sludge
5.0 g/Mg sludge
1.6 g/Mg sludge
A-16
-------
TABLE A-l. (continued)
SCC number
5-01-005-05
5-01-005-05
5-01-005-05
3-05-006-06
3-05-007-06
3-05-016-04
3-01-005-04
3-03-010-02
3-03-010-08
3-03-010-04
3-03-010-15
3-03-010-25
1-01-015-01
1-01-015-02
3-15-021-01
Source description
Medical waste incinerators: mixed
waste
Medical waste incinerators: red bag
Medical waste incinerators:
Pathological waste
Portland cement production: Dry
process
Portland cement production: Wet
process
Lime manufacture: rotary kiln
Carbon black production: Oil
furnace
Primary lead smelting: Blast
furnace
Primary lead smelting: Slag fume
furnace (including slag pouring)
Primary lead smelting: ore
crushing
Primary lead smelting: Sinter
crushing
Primary lead smelting: Sinter
leakage
Geothermal power plant: Off-gas
ejectors
Geothermal power plant: Cooling
tower
Crematories
Control
status3
U
U
U
C
C
C
C
C
C
U
U
U
U
U
U
Mercury emission factor
20 g/Mg burned
16 g/Mg burned
0.5 g/Mg burned
8.7xlO"2 g/Mg produced
8.7xlO~2 g/Mg produced
5.5xlO"2 g/Mg produced
LSxlO"4 kg/Mg produced
1.9xlO~3 kg/Mg ore concentrate
2. IxlO"3 kg/Mg lead
1.2xlO~3 kg/Mg raw material
6.5xl03 kg/Mg ore
7X10"4 kg/Mg suiter
7.3xlO'3 g/MW-hr produced
0.05 g/MW-hr produced
1.0 g/human body
aU = uncontrolled; C = controlled.
A-17
-------
REFERENCES FOR APPENDIX A
1. Little (A.D.), Inc. Exposure and Risk Assessment for
Mercury. EPA Contract 68-01-3957. U. S. Environmental
Protection Agency. 1980
2. Bureau of Mines, Division of Mineral Commodities, U. S.
Department of the Interior, Washington DC.- 1991.
3. U. S. Environmental Protection Agency. 1990 Toxics Release
Inventory. Office of Toxic Substances, Washington DC.
December 1992.
4. Bureau of Air Management. Mercury Emissions to the
Atmosphere in Wisconsin. Publication Number PUBL-AM-014.
Wisconsin Department of Natural Resources, Madison,
Wisconsin. June 1986. pp. 19-32.
5. Cole, H.S., A.L. Hitchcock, and R. Collins. Mercury
Warning: The Fish You Catch May Be Unsafe To Eat; A Study of
Mercury Contamination in the United States. Clean Water
Fund/Clean Water Action, Washington DC; August 1992.
6. Kiser, J. V. L., and D. B. Sussman, Municipal Waste
Combustion and Mercury: The Real Story. Waste Age, November
1991, Pp. 41-44.
7. U. S. Environmental Protection Agency. Emission Factor
Documentation for AP-42 Section 2.5, Sewage Sludge
Incineration. U. S. Environmental Protection Agency,
Research Triangle Park, NC. July 1993.
8. U. S. Environmental Protection Agency. Locating and
Estimating Air Emissions From Sewage Sludge Combustors. EPA
Report No. EPA-450/2-90-009. U. S. Environmental Protection
Agency, Research Triangle Park, NC. May 1990.
9. Midwest Research Institute. Medical Waste Incinerators--
Background Information for Propos'ed Standards and
Guidelines: Environmental Impacts Report for New and
Existing Facilities. Draft Report. Prepared for U. S.
Environmental Protection Agency, Research Triangle Park, NC.
N July 1992.
10. Mercury Emissions to the Atmosphere in Wisconsin.
PUBL-AM-014 Wisconsin Department of Natural Resources,
Bureau of Air Management, Madison, WI. June 1986.
11. SRI International. 1991 Directory of Chemical Producers:
United States of America. SRI International, Menlo Park,
California. 1991.
A-18
-------
12. Serth, R. W., and T. W. Hughes. Polycyclic Organic Matter
(POM) and Trace Element Contents of Carbon Black Vent Gas.
Environ. Sci. Technol., 14(3): 298-301. 1980.
13. Background Information for New Source Performance Standards:
Primary Copper, Zinc and Lead Smelters. Volume I: Proposed
Standards, Report No. EPA-450/2-74-002a. Office of Air
Quality Planning and Standards, EPA, Research Triangle Park,
NC. October 1974.
14. Robertson, D. E., E. A. Crecelius, J. S. Fruchter, and
J. D. Ludwick. Mercury Emissions from Geothermal Power
Plants. Science, 196(4294): 1094-1097. 1977.
15. Pierson, W.R., and W.W. Brachazek, Particulate Matter
Associated with Vehicles on The Road. II. Aerosol Science
and Technology 2:1-40 (1983).
16. Motor Vehicle Manufacturers Association (MVMA). MVMA Motor
Vehicle Facts and Figures '92. Motor Vehicle Manufacturers
Association, Detroit, Michigan.
17. Cremation Association of North American (CANA). Cremation
Statistics from Cremationist Journal. Compiled by CANA.
1992.
18. vander Most, P.F.J. and C. Veldt. Emission Factors Manual:
Emission Factors for Air Pollutants 1992. Report Reference
Number 92-235. TNO Environmental and Energy Research, The
Netherlands. September 1992.
19. Van Horn, W. Materials Balance arid Technology Assessment of
Mercury and Its Compounds on National and Regional Bases.
EPA 560/3-75/007. (NTIS PB-247 00/3). Office of Toxic
Substances, U. S. Environmental Protection Agency,
Washington, B.C. October 1975.
A-19
-------
APPENDIX B
SUMMARY OF COMBUSTION SOURCE MERCURY EMISSION DATA
-------
TABLE B-1. SUMMARY OF COAL COMBUSTION EMISSION DATA
Industry
sector3
U
U
U
U
U
U
U
U
U
U
U
U
U
U
ij
U
U
U
U
U
U
U
U
U
U .
Facility
typeb
PC/DB
PC/DB
PC/DB
PC/DB
PC/DB
PC/DB
PC/DB
PC/DB
PC/DB
PC/DB
PC/DB
PC/DB
PC/DB
PC/DB
PC/DB
PC/DB
PC/DB
PC/DB
PC/DB
PC/WB
PC/WB
PC/WB
PC/WB
PC/WB
PC/WB
Control
status0
ESP
WS
MP/ESP
MP/ESP
MP/ESP
ESP
UN
UN
ESP
UN
UN
UN
ESP
ESP
ESP
ESP
MP
MP/ESP
MP/ESP
MP/ESP
ESP
ESP
VS
ESP
ESP
Coal
typed
B
B
B
B
B
B
B
B
B
B
B
B
B
B
g
B
B
B
B
B
B
B
B
B
B
Emission factor6
kg/1015 J
Mean
4.7
bd
9.5
9.6
2.5
2.5
31
9.9
7.7
4.3
1.7
6.9
0.65
1.1
0.86
1.3
3.7
0.32
0.086
2.3
1.1
1.8
0.069
2.2
2.7
Range
—
—
—
—
1.5-3.5
0.56-4.2
4.9-130
—
—
_
—
—
—
—
-
-
1.6-9.1
0.18-0.86
<0.0047-0.24
—
—
—
-
—
-
lb/1012Btu
Mean
11
bd
22
22
5.9
5.8
72
23
18
10
3.9
16
1.5
2.6
2 Q
3.1
8.5
0.75
0.20
5.3
2.6
4.2
0.16
5.1
6.3
Range
-
-
—
-
3.6-8.2
1.3-9.7
11-310
—
-
—
-
-
-
—
.
-
3.7-21
0.41-2.0
<0.01 1-0.56
—
-
—
-
—
-
B-1
-------
TABLE B-1. (continued)
Industry
sector3
U
U
U
U
U
U
U
U
U
U
U
U
U
U
U
U
U
U
U
U
U
U
U
1
1 .
Facility
type"
CY
CY
CY
CY
CY
CY
CY
S
S
S
CY
CY
PC
PC
NA
NA
PC/DB
PC/DB
PC/DB
CY
CY
SS
SS
PC/DB
PC/DB
Control
statusc
WS
ESP
ESP
ESP
ESP
ESP
ESP
FF
MP
MC
UN
WS
VS
ESP
ESP
ESP
MC
MC
ESP
ESP
CY
MC
ESP
ESP
ESP'
Coal
typed
B
B
B
B
B
B
B
B
B
B
SB
SB
SB
SB
SB
SB
L
L
L
L
L
L
L
B
B
Emission factor6
kg/1015 J
Mean
2.1
1.7
2.2
4.1
7.6
4.3
2.6
2.0
11
1.1
35
2.1
4.7
1.8
0.86
0.73
1.9
2.8
< 0.099
.020
9.5
2.4
0.23
1.8
1.9
Range
—
_
—
—
—
—
—
—
—
—
—
—
—
_
—
—
~
~
—
—
_
_
—
—
-
lb/1012 Btu
Mean
4.9
4.0
5.1
9.5
18
10
6.1
4.6
26
2.5
81
4.9
11
4.1
2.0
1.7
4.4
6.5
<0.23
0.46
22
5.6
0.53
4.2
4.4
Range
-
~
—
—
—
—
~
—
—
~
—
--
—
—
-
-
-
—
—
—
—
—
-
-
-•- ' . .
B-2
-------
TABLE B-1. (continued)
Industry
sector3
1
1
1
1
1
1
1
1
1
1
1
1
1
1
1
1
1
1
1
1
1
1
1
1
1 .
Facility
type"
PC/DB
PC/DB
PC/WB
SS
SS
SS
SS
SS
SS
SS
SS
SS
OS
OS
OS
OS
OS
SS
SS
SS
SS
SS
SS
SS
SS
Control
status0
MC
MC/WS
MC
MC/ESP
MC
MC
UN
UN
UN
UN
UN
UN
UN
UN
UN
UN
MP
UN
MP/ESP
UN
MP/ESP
UN
UN
MP/ESP
UN
Coal
typed
B
B
B
B
B
B
B
B
B
B
B
B
B
B
B
B
B
B
B
B
B
SB
SB
SB
SB
Emission factor6
kg/1015 J
Mean
77
37
2.9
1.8
2.5
11
0.33
1.7
0.99
0.69
1.4
1.7
0.047
0.73
0.56
0.90
0.34
1.8
1.0
5.2
0.43
3.8
0.28
0.28
0:39
Range
—
—
—
—
—
—
0.33-0.34
1.1-2.2
—
0.56-0.86
1.1-1.7
0.69-2.8
-
-
0.32-0.82
—
0.17-0.52
_
_
—
~
0.37-7.3
—
-
- •
lb/1012 Btu
Mean
180
86
6.7
4.2
5.8
25
0.77
3.9
2.3
1.6
3.2
4.0
0.11
1.7
1.3
2.1
0.80
4.1
2.4
12
1.0
8.9
0.64
0.64
0.91
Range
—
—
-.
—
—
—
0.76-0.78
2.5-5.1
—
1.3-2.0
2.5-3.9
1.6-6.5
—
—
0.74-1.9
~
0.39-1.2
..
..
—
—
0.86-17
—
-
" -
B-3
-------
TABLE B-1. (continued)
Industry
sector3
I
C
C
C
C
C
C
C
C
R
R
R
R
Facility
type"
SS
PC/DB
PC/DB
US
SS
OS
s •
S
S
~
~
—
--
Control
status0
MP/ESP
UN
MC/WS
UN
MP
MP
UN
UN
UN
UN
UN
UN
UN
Coal
typedr
SB
B
B
B
B
B
A
A
A
B
B
. B
B
Emission factor6
kg/1015 J
Mean
0.16
2.5
0.47
0.18
0.60
5.6
3.0
1.5
2.3
3.3
10
11
<0.39
Range
—
_
—
-.T«J"..
—
-
—
-
-
—
—
—
-
lb/1012 Btu
Mean
0.37
5.8
1.1
.0.42
1.4
13
7.0
3.5
5.3
7.7
23
27
<0.9
Range
-
—
—
—
—
-
~
-
-
_
—
- —
-
aU = utility, I = industrial, C = commercial, R = residential
bPC = pulverized coal, DB = dry bottom, WB = wet bottom, CY = cyclone, NA = not available,
SS = spreader stoker, OS = overfeed stoker, US = underfeed stoker, S = stoker
CESP = electrostatic precipitator, WS = wet scrubber, MP = mechanical precipitation device,
UN = uncontrolled, VS = venturi scrubber, FF = fabric filter, MC = multiclone,
CY = cyclone
dB = bituminous, SB = subbituminous, L = lignite, A = anthracite
ebd = below detection limit
B-4
-------
TABLE B-2. SUMMARY OF MUNICIPAL WASTE COMBUSTOR EMISSION DATA
Facility name
Adirondack (Boiler A)
Adirondack (Boiler B)
Adirondack (Boiler B)
Adirondack average
Camden (Unit 1)
Commerce
Commerce
Commerce
Commerce average
Quebec City - Pilot
Quebec City - Pilot
Quebec City - Pilot
Quebec City - Pilot
Quebec City - Pilot
Quebec City - Pilot
Quebec City average
Vancouver (11/88)
Vancouver (3/89)
Vancouver (4/89)
Vancouver (8/89)
Vancouver averaae
Babylon
Bristol
Bristol
Bristol
Bristol
Bristol average
Commerce (1987)
Commerce (1988)
Commerce (1988)
Commerce- average
Fairfax
Fairfax
Fairfax
Fairfax
Fairfax average
Combustor
type3
MB/WW
MB/WW
MB/WW
MB/WW
MB/WW
MB/WW
MB/WW
MB/WW
MB/WW
MB/WW
MB/WW
MB/WW
MB/WW
MB/WW
MB/WW
MB/WW
MB/WW
MB/WW
MB/WW
MB/WW
MB/WW
Mb/WW
MB/WW
MB/WW
MB/WW
MB/WW
MB/WW
MB/WW
MB/WW
MB/WW
MB/WW
MB/WW
MB/WW
MB/WW
MB/WW
MB/WW
Control
technology
U
U
U
U
U
UN
UN
UN
UN
UN
UN
UN
UN .
UN
UN
UN
UN
UN
UN
UN
UN
SD/FF
SD/FF
SD/FF
SD/FF
SD/FF
SD/FF
SD/FF
SD/FF
SD/FF
SD/FF
SD/FF
SD/FF
SD/FF
SD/FF
SD/FF
Concentration
//g/dscm @ 7% 02
328
659
439
475
710
450
453
261
388
445
360
451
320
480
187
374
527
1,200
1,360
661
937
323
99.0
10
64.0
399
167
570
68.0
39.0
226
331
406
466
514
429
-------
TABLE B-2. (continued)
Facility name
Hempstead, Unit 1(9/89)
Hempstead, Unit 2(9/89)
Hempstead, Unit 3(10/89)
Hempstead average
Huntsville
Huntsville
Huntsville average
Indianapolis
Indianapolis
Indianapolis, Unit 1
Indianapolis average
Kent
Kent
Kent average
Long Beach
Marion Countv
Stanislaus County
Stanislaus County
Stanislaus County
Stanislaus County, Unit 1
Stanislaus County, Unit 2
Stanislaus Countv averaae
Adirondack (Boiler A)
Adirondack (Boiler B)
Adirondack (Boiler B)
Adirondack average
Camden (Unit 1)
Charleston (Units A & B)
Charleston (Unit A)
Charleston (Unit B)
Charleston average
Haverill, Unit A (6/89)
Haverill, Unit B (3/90)
Haverill, Unit B (6/89)
Haverill averaae
Combustor
type3
MB/WW
MB/WW
MB/WW
MB/WW
MB/WW
MB/WW
MB/WW
MB/WW
MB/WW
MB/WW
MB/WW
MB/WW
MB/WW
MB/WW
MB/WW
MB/WW
MB/WW
MB/WW
MB/WW
MB/WW
MB/WW
MB/WW
MB/WW
MB/WW
MB/WW
MB/WW
MB/WW
MB/WW
MB/WW
MB/WW
MB/WW
MB/WW
MB/WW
MB/WW
MB/WW
Control
technology1*
SD/FF
SD/FF
SD/FF
SD/FF
SD/FF
SD/FF
SD/FF
SD/FF
SD/FF
SD/FF
SD/FF
SD/FF
SD/FF
SD/FF
SD/FF
SD/FF
SD/FF
SD/FF
SD/FF
SD/FF
SD/FF
SD/FF
SD/ESP
SD/ESP
SD/ESP
SD/ESP
SD/ESP
SD/ESP
SD/ESP
SD/ESP
SD/ESP.
SD/ESP
SD/ESP
SD/ESP
SD/ESP
Concentration
^g/dscm @ 7% 02
9.28
25.5
25.0
19.9 *
463
1,280
869
200
277
283
253
166
248
207
180
239
427
508
481
499
462
475
574
74.8
131
87.7
217
723
457
498
559
247
567
208
341
B-6
-------
TABLE B-2. (continued)
FacilitY name
Military, Unit 1
Millbury, Unit 2
Millbury average
Portland, Unit 1 (1 2/89)
Portland, Unit 2 (12/89)
Portland averaae
Hillsborough
Pinedas County
Quebec City
Tulsa
Tulsa
Tulsa
Tulsa
Tulsa
Tulsa
Tulsa
Tulsa average
Vancouver (12/89)
Vancouver (12/89)
Vancouver (12/89)
Vancouver (3/S9!
Vancouver (4/89)
Vancouver (8/89)
Vancouver, Unit 1 (9/89)
Vancouver, Unit 2 (9/89)
Vancouver, Unit 3 (11/88)
Vancouver, Unit 3 (9/89)
Vancouver, Unit 3 (9/89)
Vancouver average
Delaware (Unit 1)
Delaware (Unit 2)
Delaware (Unit 3)
Delaware (Unit 4)
Delaware (Unit 5)
Delaware (Unit 6)
Combustor
type3
MB/WW
MB/WW
MB/WW
MB/WW
MB/WW
MB/WW
MB/WW
MB/WW
MB/WW
MB/WW
MB/WW
MB/WW
MB/WW
MB/WW
MB/WW
MB/WW
MB/WW
MB/WW
MB/WW
MB/WW
MRAA/W
MB/WW
MB/WW
MB/WW
MB/WW
MB/WW
MB/WW
MB/WW
MB/WW
MB/RC
MB/RC
MB/RC
MB/RC
MB/RC
MB/RC
Control
technology*5
SD/ESP
SD/ESP
SD/ESP
SD/ESP
SD/ESP
SD/ESP
ESP
ESP
ESP
ESP
ESP
ESP
ESP
ESP
ESP
ESP
ESP
DSI/FF
DSI/FF
DSI/FF
DSI/FF
DSI/FF
DSI/FF
DSI/FF
DSI/FF
DSI/FF
DSI/FF
DSI/FF
DSI/FF
SD/FF
SD/FF
SD/FF
SD/FF
SD/FF
SD/FF
Concentration
ug/dscm @ 7% O2
565
954
760
550
382
466
823
847
685
746
466
711
600
418
1,000
97.0
577
156
117
127
456
632
95.0
470
368
485
1,080
1,090
461
40.6
22.6
30.5
27.3
54.3
84.1
B-7
-------
TABLE B-2. (continued)
Facility name
Delaware (Unit 1)
Delaware (Unit 2)
Delaware (Unit 3)
Delaware (Unit 4)
Delaware (Unit 5)
Delaware (Unit 6)
Delaware average
York (Unit 1 )
York (Unit 2)
York (Unit 3)
York (Unit 1 )
York (Unit 2)
York (Unit 3)
York (Unit 1 )
York (Unit 2)
York (Unit 3)
York (Unit!)
York (Unit 2)
York (Unit 3)
York (Unit 1 )
York (Unit 1 )
York (Unit 2)
York (Unit 3)
York (Unit 1 )
York (Unit 2)
York (Unit 3)
York average
AVERAGE
Dayton
Dayton
Dayton
Dayton
Dayton
Average
Combustor
type3
MB/RC
MB/RC
MB/RC
MB/RC
MB/RC
MB/RC
MB/RC
MB/RC
MB/RC
MB/RC
MB/RC
MB/RC
MB/RC
MB/RC
MB/RC
MB/RC
MB/RC
MB/RC
MB/RC
MB/RC
MB/RC
MB/RC
MB/RC
MB/RC
MB/RC
MB/RC
MB/RC
MB/RC
MB/REF
MB/REF
MB/REF
MB/REF
MB/REF
MB/REF
Control
technology
SD/FF
SD/FF
SD/FF
SD/FF
SD/FF
SD/FF
SD/FF
SD/FF
SD/FF
SD/FF
SD/FF
SD/FF
SD/FF
SD/FF
SD/FF
SD/FF
SD/FF
SD/FF
SD/FF
SD/FF
SD/FF
SD/FF
SD/FF
SD/FF
SD/FF
SD/FF
SD/FF
SD/FF
UN
UN
UN
UN
UN
UN
Concentration
//g/dscrn @ 7% O2
30.1
50.2
57.6
87.0
41.0
42.8
47.4
158
105
79.3
151
167
136
155
167
136
36.1
53.0
120
48.4
54.0
55.4
40.1
153
79.2
150
110
70.6
716
907
962
973
1,060
923
B-8
-------
TABLE B-2. (continued)
Facility name
Dayton
Dayton
Average
Davton
Biddeford
Mid-Connecticut (2/89)
Mid-Connecticut (7/88)
Mid-Connecticut (7/88)
Mid-Connecticut Average
Mid-Connecticut (2/89)
Mid-Connecticut (7/88)
Mid-Connecticut Average
Honolulu, Unit 1
Honolulu, Unit 2
Average
Semass, Unit 1
Semass, Unit 2
Average
West Palm Beach, Unit 1
West Palm Beach, Unit 2
Average
Detroit (3/90)
Detroit (7/89)
Average
Albany
Pigeon Point
Pooe/Douqlas
Dversburg
Oneida County
Combustor
type3
MB/REF
MB/REF
MB/REF
MB/REF
RDF
RDF
RDF
RDF
RDF
RDF
RDF
RDF
RDF
RDF
RDF
RDF
RDF
RDF
RDF
RDF
RDF
RDF
RDF
RDF
RDF
MOD/EA
MOD/EA
MOD/SA
MOD/SA
Control
technology'5
ESP
ESP
ESP
DSI/ESP
UN
UN
UN
UN
UN
SD/FF
SD/FF
SD/FF
SD/ESP
SD/ESP
SD/ESP
SD/ESP
SD/ESP
SD/ESP
SD/ESP
SD/ESP
SD/ESP
ESP
ESP
ESP
ESP
ESP
ESP
UN
ESP
Concentration
x/g/dscm @ 7% O2
1,020
1,150
1,080
491
389
668
1,010
884
853
9.20
50.0
29.6
5.28
7.25
6.27
59.3
105
82.2
55.6
23.2
39.4
194
653
424
441
363
133
130
2.060
aMB = mass burn, WW = water wall, REF
MOD = modular, SA = starved air, EA =
bUN = uncontrolled, SD = spray dryer, FF
DSI = duct sorbent injection.
= refractory wall, RDF = refuse-derived fuel-fired,
excess air.
fabric filter, ESP = electrostatic precipitator,
B-9
-------
TABLE B-3. SUMMARY OF SEWAGE SLUDGE INCINERATOR EMISSION DATA
Incinerator
type3
MH
FB
MH
NA
FB
FB
MH
MH
MH
MH
MH
MH
MH
MH
NA
MH
MH
FB
Control
status0
IS
SC
IS
NA
VS/IS
VS/IS
NA
VS/IS
NA
UN
UN
UN
UN
UN
UN
UN
IS
- VS/IS
Method0
T
T
T
T
T
NA
T
T
NA
MB
MB
MB
MB
MB
MB
MB
T
- T
Emissio
g/Mg dry sludge
0.35
24
0.90
1.5
1.6-3.1
0.026
0.83 - 14
1.1
3.0
0.54 - 0.84
0.66
4.6
3.4 - 4.0
1.2 - 2.1
0.32
0.58
0.97
0.030
n factor
10"3 Ib/ton dry sludge
0.70
48
1.8
3.0
? 3.2-6.2
0.051
1.7-27
2.1
6.0
1.1 - 1.7
1.3
9.2
6.8 - 8.0
2.4 - 4.2
0.64
1.2
1.9
0.060
Ref.
51
51
51
51
51
14
14
14
14
14
14
14
14
14
14
14
49
49
aMH = multiple hearth, FB = fluidized-bed, NA = not available.
bIS = impingement scrubber, SC = spray chamber, NA = not available, VS = venturi scrubber,
UN = uncontrolled.
CT = source test, NA = not available, MB = mass balance.
B-10
-------
TABLE B-4. SUMMARY OF MEDICAL WASTE INCINERATOR EMISSION DATA
Facility
Fox Chase
Southland
Royal
Jubilee0
Meaa
Nazareth
St.
Bernadines
Kaiser
use
Borgess
University
of Michiaan
Lenoir
Cane Fear
AMI
Central
Carolina
Morristown
Waste
type*
M
M
M
NA
M
M
M
M
GSOO
RB
G100
M
M
M
M
P
M
Control
status0
VS/PB
DSI/ESP
UN
VS/PB
VS/PB
UN
WS
UN
UN
OI/FF A
DI/FF + Cd
DI/FF + C8
UN
DI/FF
UN
UN
VS/PB
UN
UN
UN
UN
UN
SD/FF
SD/FF + C
No. of
runs
3
3
2
3
2
3
3
3
14
9
2
3
10
9
2
3
3
9
9
3
6
6
3
3
Emission factor
a/Ma of waste
Averaae
0.72
9.0
0.0129
3.22
14
9.7
15.8
317
66.2
5O.O
5.84
2.48
16.2
26.2
1.13
4.03
3.66
7.15
11.6
0.043
0.5
37.1
23.9
3.98
Ranae
_
2.73-16.7
0.01 24-O.0 134
2.08-4.24
8.1-2.0
8.4-12.2
0.41-33.4
9.92-914
2O.3-165
19.5-109
5.25-6.42
0.739-4.18
0.922-630
2.61-84.2
0.24O-2.O1
1.98-5.35
0.74-7.26
1.05-510
0.58-56O
<0.00055-O.081
not available, GSOO = mixed waste from 500-bed hospital, RB = red bag waste,
G100 = mixed waste from 100-bed hospital, P = pathological waste.
bVS = venturi scrubber, PB = packed bed, OSI = duct sorbent injection, ESP = electrostatic precipitator,
UN = uncontrolled, WS = wet scrubber, Dl = dry injection, FF = fabric filter, C = carbon addition,
SD = spray dryer.
°Sampling method suspect, results biased low.
dCarbon injection at 1 Ib/hr rate.
aCarbon injection at 2.5 Ib/hr rate.
B-ll
-------
APPENDIX C.
SELECTED INFORMATION FOR CEMENT KILNS AND LIME PLANTS
C.I - UNITED STATES PORTLAND CEMENT
KILN CAPACITIES--1990
C.2 - SUMMARY OF PORTLAND CEMENT
EMISSION FACTORS
C.3 - LIME PLANTS IN THE UNITED STATES
IN 1991
-------
TABLE C-1. PORTLAND CEMENT PRODUCTION FACILITIES
Company and location
Alamo Cemant Co.
San Antonio, TX
Allantown Cament Co., Inc.
Blandon, PA
Armstrong Cament & Sup. Co.
Cabot, PA
Ash Grova Cemant Co.
Naphi, UT
Louisville, NE
Durkea, OR
Foreman, AR
Montana City, MT
Chanute, KS
Inkom, IO
Blue Circle Inc.
Ravena, NY
Atlanta, GA
Tulsa, OK
Calara, AL
Boxcrow Cament
Midlothian, TX
Calaveras Cament Co.
Redding, CA
Tehachapi, CA
California Portland Cement
Mojave, CA
Colton, CA
Rillito, AZ
Capitol Cement Corporation
Martinsburg, WV
Capitol Aggregates, Inc.
San Antonio, TX
Carlow Group
Zanesville, OH
Centex
Laramie, WY
La Salle, IL
Fernley, NV
Continental Cement Co., Inc.
Hannibal. MO
Dixon-Marquette
Oixon, IL
Dragon Products Company
Thomaston, ME
Essroc Materials
Nazareth, PA
Speed, IN
Bessemer, PA
Frederick, MO
Logansport, IN
No. /type of kiln
1 - Dry
2- Dry
2- Wet
1 -Dry
2 -Dry
1 - Dry
3 - Wet
1 • Wet
2 -Wet
2- Wet
2 -Wet
2 -Dry
2 -Dry
2- Dry
1 - Dry
1 - Dry
1 -Wet
1 -Dry
2 -Dry
4- Dry
3 -Wet
1 -Dry/1 -Wet
2 -Wet
1 -Dry
1 -Dry
2 -Dry
1 - Wet
4 -Dry
1 -Wet
1 - Dry
2 -Dry
1 -Dry/1 -Wet
2- Wet
2 -Wet
Clinker capacity,8
103 tons/year
750
930
310
600
961
500
945
280
496
210
1,532
612
600
600
1,000
651
425
1,039
750
1,065
822
503/352
603
461
410
415
600
524
455
963
951
. 325/21 1
370
404
C-1
-------
TABLE C-1. (continued)
Company and location
Florida Crushed Stone
Brooksville. FL
Giant Cement Company
Harlayville, SC
Gifford-Hill & Co., Inc.
Harteyville, SC
Oro Grande, CA
Riverside, CA
Glens Falls Cement Co.
Glens Falls, NY
Hawaiian Cement Company
Ewa Beach, HI
Heartland Cement Company
Independence, KS
Hercules Cement Company
Stockertown, PA
Holnam, Inc.
Theodore, AL
Claricsville, MO
Holly Hill, SC
Mason City, IA
Florence, CO
Fort Collins, CO
Dundee, Ml
Artesia, MS
Seattle, WA
Three Forks, MT
Ada, OK
Tijeras, NM
Saratoga, AR
Morgan, UT
Independent Cement Corp.
Catskill, NY
Hagsrstown, MO
Kaiser Cement Corp.
Permanente, CA
Keystone Cement Company
Bath, PA
Kosmos Cement Co.
Louisville, KY
Pittsburgh, PA
LaFarge Corporation
New Braunfels, TX
Buffalo, IA
Demopolis, AL
Grand Chain, IL
Alpena, Ml
Whitehall, PA
Sugar Creek. MO
Paulding, OH
Fredonia, KS
No. /type of kiln
1 - Dry
4- Wet
1 -Dry
7 -Dry
2- Dry
1 -Dry
1 -Dry
4- Dry
3 -Dry
1 -Dry
1 -Wet
2 -Wet
2 -Dry
3- Wat
1 -Dry
2- Wet
1 -Wet
1 -Wet
1 -Wet
2 -Wet
2 -Dry
2- Wet
2- Wet
1 -Wet
1 -Dry
1 - Dry
2- Wet
1 -Dry
1 -Wet
1 -Dry
1 -Dry -
1 - Dry
2 -Dry
5 -Dry
3 -Dry
2 -Dry
2- Wet
2- Wet
Clinker capacity,3
10 tons/year
571
870
617
1,148
110
495
263
336
723
*
1,442
1,312
1,092
888
860
494
970
5O4
473
312
600
494
369
328
512
498
1,600
602
724
. 394
954
858
722
1,186
1,954
760
482
490
382
C-2
-------
TABLE C-1. (continued)
Company and location
Lehigh Portland Cement
Mason City, IA
Leeds, AL
Cementon, NY
Union Bridge, MO
Mitchell, IN
York, PA
Waco, TX
Lone Star Industries
Cape Girardeau, MO
Greencastle, IN
Oglesby, IL
Pryor, OK
Nazareth, PA
Sweetwater, TX
Medusa Cement Co.
Charievoix, Ml
Clinchfield, GA
Wampum, PA
Mitsubishi Cement Corp. •
Lucerne Valley, CA
Monarch Cement Company
Humboldt, KS
Das Moines, IA
National Cement Company
Ragland, AL
Natl. Cement Co. of Califorina
Lebec, CA
North Texas Cement
Midlothian. TX
Phoenix Cement Company
Clarkdale, AZ
Rinker Portland Cement Corp.
Miami, FL
River Cement Company
Festus, MO
RMC Lonestar
Davenport, CA
Roanoke Cement Company
Cloverdale, VA
Signal Mountain Cement Co.
Chattanooga, TN
South Dakota Cement
Rapid City, SD
Southdown, Inc.
Victorville, CA
Brooksville, FL
Knoxviile, TN
Fairborn, OH
Lyons, CO
Odessa, TX
No. /type of kiln
1 -Dry
1 - Dry
1 - Wet
4 -Dry
3 -Dry
1 -Wet
1 -Wet
1 -Dry
1 -Wet
1 -Dry
3 -Dry
4 - Dry
3 - Dry
1 -Dry
1 -Dry/1 -Wet
3- Dry
1 -Dry
3- Dry
2 - Wet
1 - Dry
1 - Dry
3- Wet
3 -Dry
2- Wet
2 -Dry
1 -Dry
5 -Dry
2 -Wet
1-Dry/2-Wet
2 -Dry
2 -Dry
1 -Dry
1 -Dry
1 - Dry
2 -Dry
Clinker capacity,3
10^ tons/year
760
651
. . 558
992
760
99
81
1,104
715
465
687
623
495
1,364
56O/206
703
1,669
674
300
845
650
900
705
564
1,179
800
1,117
45O
45O/316
1,550
1,200
600
610
450
550
C-3
-------
TABLE C-1. (continued)
Company and location
St. Mary's Peerieas Cement Co.
Detroit, Ml
Tarmac Florida, Inc.
Medley, FI_
Texas Industries
New Braunfels, TX
Midlothian, TX
Texas-Lehigh Cement Co.
Buda. TX
Total capacity reported
No. /type of kiln
1 - Wet
3- Wet
1 - Dry
4 - Wet
1 - Dry
1 35 - Dry/79 - Wet
Clinker caoacity,9
103 tons/year
610
1,028
759
1,256
987
81,056
Source: U.S. and Canadian Portland Cement Industry: Plant Information Summary. December 31, 1990. Portland Cement
Association, Skokia, Illinois. July 1991.
aNote:
Kilns reported as inactive in 1990
Ash Grove Cement
California Portland Cement
Holnam, Inc.
Lone Star Industries
Medusa Cement Company
Monarch Cement Company
Tarmac Florida
Total active capacity
Foreman, AR
Rillito, AZ
Florence, CO
Swoatwater, TX
Clinchfield, GA
Das Moines, IA
Medby, FL
1 kiln
2 kilns
2 kilns
1 kiln
1 kiln
2 kilns
2 kilns
Clinker capacity, 10*
tons/yr
271
•270
368
165
206
300
368
79,108
C-4
-------
TABLE C-2. SUMMARY OF MERCURY EMISSION FACTORS FOR PORTLAND CEMENT PRODUCTION
Facility
Lone Star Industries
Lone Star Industries
LaFarge Corp.
Ash Grove Cement Co.
Ash Grove Cement Co.
Ash Grove Cement Co.
Ash Grove Cement Co.
Ash Grove Cement Co.
Ash Grove Cement Co.
Essroc Materials
Essroc Materials
LaFarge Corp.
Lone Star Industries
Lone Star Industries
Holnam Inc.
Facility location
Cape Girardeau, MO
Cape Girardeau, MO
Oemopolie, AL
Foreman, AR
Foreman, AR
Chanute, KS
Chanute, KS
Louisville, NE
Louisville, NE
Frederick, MD
Frederick, MD
Paulding, OH
Oglesby, IL
Oglesby, IL
Clarksville, MO
Control
status8
BH
BH
ESP (2)
ESP
ESP
ESP
ESP
ESP
ESP
12)
NS
NS
ESP
ESP
ESP
ESP
No. of
runs
:)
:)
:l
i5
4
4
4
3
4
a
a
a
•t
a
a
Average clinker
production rate
Mg/hr (tons/hr)
149 (164)
Phase 1 test
146(160)
Phase 2 test
102(112)
45 (49)
Kiln No. 3
32 (35)
Kiln No. 1
30 (33)
Kiln No. 1
30 (33)
Kiln No. 2
40 (44)
Kiln No. 1
57 (63)
Kiln No. 2
43 (47)
Test No. 1
44 (48)
Test No. 2
55(61)
54 (59)
Test No. 1
64 (60)
Test No. 2
163 (180)
Emission factor
10'3kg/Mg of clinker
Average
0.01
0.22
0.08
0.02
0.04
0.49
0.08
0.047
0.015
0.11
0.11
0.016
0.0023
0.014
0.049
Range
0.0088-0.013
0.113-0.4
0.067 - 0.090
0.011 -0.028
0.022 - 0.055
0.14- 1.25
0.033-0.15
0.03 - 0.067
0.01 - 0.030
0.076-0.13
0.076-0.14
0.014-0.018
0.0016-0.0030
0.006 - 0.020
0.036 - 0.06
10 d Ib/ton of clinker
Average
0.020
0.43
0.16
0.035
0.07
0.97
0.15
0.095
0.030
0.22
0.22
0.032
0.0045
0.028
0.097
Range
0.0176-0.0252
0.225 - 0.8
0.134-0.179
0.022 - 0.055
0.043-0.11
0.28 - 2.5
0.066 -'0.29
0.05-0.123
0.019-0.059
0.15-0.26
0.15-0.27
0.028 - 0.036
0.0032 - 0.0059
0.012 - 0.040
0.072-0.12
n
tn
aBH = baghouse
ESP = electrostatic precipitator
NS = not stated
-------
TABLE C-3. LIME PLANTS ACTIVE IN THE UNITED STATES IN 1991a
(Source: National Lime Association)
Company/headquarters location
Alabama
Allied Lima Company (HQ)
Birmingham. AL
Blue Circle. Inc.
Calera. AL
Cheney Lime & Cement Company
Allgood. AL
Oravo Lime Company
Saginaw, AL
Arizona
Chemstar Lime, Inc. (HQ)
Phoenix. AZ
Magma Cooper Company (C)
San Manuel, AZ
Arkansas
Arkansas Lime Company
Batasville. AR
California
Spreckles Sugar Company, Inc. (C)
Woodland. CA
Chemstar Lime, Inc. (HQ)
Phoenix, AZ
Delta Sugar Corp. (C)
Clarksburg, CA
Holly Sugar Corp. (C)
Colorado Springs, CO
Marine Magnesium Company (C)
S. San Francisco, CA
National Refractories & Minerals Corp.
Moss Landing, CA
Union Sugar Division of Holly Sugar Corp. (C)
Santa Maria. CA
Colorado
Calco, Inc.
Salida, CO
Western Sugar Company
Port Morgan, CO
Greeley, CO
Idaho
The Amalgamated Sugar Company (C)
Nampa, ID
Paul, ID
Twin Falls, ID
Phoenix, AZ
Illinois
Marblehead Lime Company (HQ)
Chicago, IL
Vulcan Materials Company
Countryside, IL
Inland Steel Company (C) .
E. Chicago. IN
Iowa
Lin wood Mining & Minerals Corp.
Davenport, IA
Plant location/name
•
Alabaster
Montevallo
Roberta
Landmark
Allgoodb
Longview Div.
Douglas
Nelson
San Manuel
Batesville
Woodland
City of Industry"
Stockton15
Clarksburg
Hamilton City
Brawley
Tracy
Sonora
Natividad
Betteravia
Salida
Fort Morgan
Greeley
Nampa
Mini-Cassia
Twin Fall*
Ten Mile0
South Chicago
Thornton
Buffington
McCook
Indiana Harbor
LJnwood (UG)
Type of lime produced
Q
Q, H
Q, H
Q, H
H
Q. H
Q
Q, H
H
Q, H
Q
H
H
H
Q
Q
Q
Q
DL
Q
Q
Q
Q
Q
Q
Q
Q
Q, H
DL, DH, DB
Q
DL
Q
Q. H
C-6
-------
TABLE C-3. (continued)
Company/headquarters location
Kentucky
Dravo Lima Company (HQ)
Pittsburgh, PA
Louisiana
Dravo Lima Company (HQ)
Pittsburgh, PA
USG Corp. (HQ)
Chicago, IL
Massachusetts
Laa Lima Corp.
Lae, MA
Pfizer, Inc.
Adams. MA
Michigan
Datroit Lime Company
Detroit, Ml
The Dow Chamical Company (C)
Ludington. Ml
Marblahaad Lima Company (HQ)
Chicago, IL
Michigan Sugar Company (C)
Saginaw, Ml
Monitor Sugar Company (C)
Bay City, Ml
Minnesota
American Crystal Sugar Company (C)
Moorhead, MN
Southern Minn. Sugar Corp. (C)
a -:u- fcJM
Missouri
Ash Grove Cament Company
Springfield, MO
Mississippi Lime Company (HQ)
Alton, IL
Resco Products of Missouri, Inc. (HQ)
Clearfield, PA
Montana
Continental Lime, Inc.
Townsend, MT
Holly Sugar Corp. (C)
Colorado Springs, CO
Western Sugar Company
Billings, MT
Nebraska
Western Sugar Company (C)
Bayard, NE
Mitchell, NE
Scottsbluff, NE
Nevada
Chamstar Lime, Inc. (HQ)
Phoenix, AZ
Continental Lime, Inc.
Wendover, NV
Plant location/name
Black River Div. (UG)
Maysvilla Div. (HG)
Pelican5
New Orleans
Lee
Adams
River Rouge
Ludington
River Rouge
Brennan
Sebawaing
Carollton
CroMwell
Caro
Bay City
Moorhead
Crookston
East Grand Forks
o iii-
Springfield
Ste. Genevieve (UG)
Bonne Terra
Indian Creek
Sidney
Billings
Bayard
Mitchell
Scottsbluff
Apex
Henderson
Pilot Peak
Type of lime produced
Q, H
Q
% H
Q, H
DL. DH
Q
Q
DL
Q
Q, H
Q
Q
Q
Q
Q
Q
Q
Q
Q
Q, H
Q, H
DL, Q, DB
Q
Q
Q
Q
Q
Q
Q, H
DL, OH
Q
C-7
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TABLE C-3. (continued)
Company/headquarters location
North Dakota
American Crystal Sugar Company (C)
Orayton, ND
Hilleboro, NO
Minn-Oak Farmers Corp. (C)
Wahpeton, NO
Ohio
Elkem Motels Company (C)
Astabula, OH
GenLime Group LP
Genoa, OH
The Great Lake* Sugar Company (C)
Fremont, OH
Huron Ume Company
Huron, OH
LTV Steel (C&S)
Grand River, OH
Martin Mariana (C&S)
Woodville, OH
National Lime & Stone Company
Findlay, OH
Ohio Lime Company
Woodville, OH
Oklahoma
St. Clair Lime Company
Oklahoma City, OK
Oregon
The Amalgamated Sugar Company (C)
Nyssa, OR
Ash Grove Cement Company
Portland, OR
Pennsylvania
J.E. Baker Company (C&S)
York, PA
Bellefonte Lime Company
Bellefonte, PA
Centre Ume & Stone Company
Pleasant Gap, PA
Con Lime Company
Bellefonte, PA
Corson Lime Company
Plymouth Meeting, PA
Mercer Lime & Stone Company
Pittsburgh, PA
Warner Company
Oevault, PA
Wimpey Minerals PA, Inc.
Annville, PA
Puerto Rico
Puerto Rican Cement Company, Inc.
Ponce, PR
South Dakota
Pete Lien & Sons, Inc.
Rapid City, SD
Plant location/name
Drayton
Hillsboro
Minn-Dak
Ashtabula
Genoa
Fremont
Huron
Grand River
Woodville
Carey
Woodville
Millersville
Marble City (UG)
Nyssa
Portland
York
Bellefonte
Pleasant Gap
Bellefonte (UG)
Plymouth Meeting
Branchton
Cedar Hollow
Hanover
Annville
Ponce
Rapid City
Type of lime produced
Q
Q
Q
4
a
DL, DH
Q '
Q
Q
DL, DB
DL, DH
DL
DL
Q, H
Q
Q, H
DB
Q. H
Q, H
Q, H
DL, DH
Q, H
DL, DH
DL, Q
Q, H
Q. H
Q, H
C-8
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TABLE C-3. (continued)
Company/headquarters location
Tennessee
Bowater Southern Paper Corp. (C)
Calhoun, TN
Tenn Luttrell Company
Luttrell, TN
Texas
APG Lime Corp.
New Braunfels, TX
Austin White Lime Company
Austin, TX
Chemical Lime, Inc.
Clifton, TX
Holly Sugar Corp. (C)
Colorado Springs, CO
Redland Stone Products Company
San Antonio, TX
Texas Lime Company
Cleburne, TX
Utah
C hems tar Lime, Inc. (HQ)
Phoenix, AZ
Continental Lime, Inc.
Delta, UT
M.E.R.R. Corp.
Grantsville, UT
Virginia
APG Lime Corp
Ripplemead, VA
Chemstone Corp.
Strasburg, VA
W.S. Fray Company, Inc.
York, PA
DiisArmn f*/\m //?\
Riverton, VA
Shorn/alley Lime Corp.
Stephens City, VA
Virginia Lime Company
Ripplemead, VA
Washington
Northwest Alloys, Inc. (C)
Addy, WA
Continental Lime, Inc.
Tacoma, WA
West Virginia
Germany Valley Limestone Company
Riverton, WV
Wisconsin
CLM Corp. (HQ)
Duluth, MN
Rockwell Lime Company
Manitowoc, Wl
Western Lime & Cement Company
West Bend, Wl
Plant location/name
Calhoun
Luttrell (UG)
New Braunfels
McNeil
Cliefton
Marble Falls
Hereford
San Antonio
No. 1
Round Rockd
Dolomite
Cricket Mountain
Marblehead Mt.e
Kimballton (UG)
Dominion
Clearbrook
Riverton
Stepens City*9
Kimballton (UG)
Addy
Tacoma
Riverton
Superior
Manitowoc
Green Bay
Eden
Type of lime produced
Q
Q, H
Q, H, DL, OH
Q, H
Q, H
DL
Q
Q. H
Q, H
Q, H
DL, OH
Q
DL
Q, H
Q, H
Q
H
H
Q, H
DL
Q, H
Q, H
Q, H
DL, DH
Q, H
DL, DH
C-9
-------
TABLE C-3. (continued)
Company/headquarters location
Wyoming
Holly Sugar Company (C)
Colorado Springe, CO
The Western Sugar Company (C)
Lovell, WY
Plant location/name
Torrington
Worland
Lowell
Type of lime produced
Q
Q
Q
C
c&s
08
OH
DL
H
HQ
Q
UG
LJme plant is operated predominantly for captive consumption.
Captive and sales—captive consumption with significant commercial sales.
Refractory, dead-burned dolomite.
Dolomitic hydrate.
Oolomitic quicklime.
Hydrated lime.
Headquarters address.
Quicklime.
Underground mine.
aExcludes regenerated lime.
Hydrating plant only.
°New plant, scheduled to come on-line August 1992.
dPlant did not operate in 1991; it has been mothballed.
aClosed December'1991, last shipments made May 1992.
C-10
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APPENDIX D.
CRUDE OIL DISTILLATION CAPACITY
-------
Op«raM« AJmotplwrte Cnid« 00 OWlUttttn Capacity •» o» January 1. i »9J
OwmnU.SA.iiw
Pen *i»»». T,
tinUlM cay. Uafc
EnnC*. UAA
Amoco OlCa
T.M.CI*. T«a
411.000
110.000
SMOJCo.
Wood Wwr. »<•• .
OMrPM.T«a>....
WOOD
40.000
2*.ooo
274.000
2U.900
JHQOO
144.100
UoMQICa^.
VOICvp.
8«t» CMM* (AJI»M), 1
UnaOh*..-
Totato. OH.
F«MM».«ini
278.000
HO.OOO
110.000
1ZHOOO
100.000
741.400
2U.OOO
160.000
141.000
12*. MO
USX Cop.
120.000
2SI.OOO
179.000
70.000
70.000
90.000
•15.000
2M.OOO
225.000
1*0.000
814.000
171.000
TU«, Otwon
SuiMtowif *M*>U«nf
199.000
M.OOO
NOK* (O«M HOOT).
Kim Scnngi. kouwam „
SMI MM. lauiMw
2SO.SOO
I19.«00
70.100
D-l
-------
Rcfliwra* Op«nM* Atmo
-------
RaflMra' OpwaM* AtmoaplMric Ciuott Oil Distinction Capacity M at January i, 1992
(ContbiiMd)
Oar
-------
Rcfliwr*' OpmAte Atmospheric dud* Oil Distuwian Capacity M of January 1,1992
(Continued,
TranmnM Ol U.&A. Inc.
I
Cm*
WarMOiCo.
iPM>
IZSOO I
IJ.OOO
12.000
11.500
7.000
CMtrautf Corp.
TvwPirTwi IP
Actmond, VVQIMII «..nv..._ .......
(Mbing Corp
11.500 i SamiMl
10.HO
|Co.
San Mvy«. WM VirgnC..
IMMngC*.
•n CIV. MM
ONCEMtwCap.
(.700
«.tao
1.000
1700
5J40
1SOO
4JOO
4.000
4.000
3.000
3.000
t.700 I
UmkyT>«aM
UL8. TtM 11 tMi.111
• r,
t -
•Ca.Lf.
•tMM »MMng r^i^rry. January 1. 1MO
O.C.
D-4
-------
TECHNICAL REPORT DATA
(Please read Inilruciiont on iHt reverie before eomplennfl
. REPORT NO.
EPA-454/R-93-023
3. RECiPIENT'S ACCESSION NO.
4. TITLE AND SUBTITLE
5. REPORT DATE
Locating and Estimating Air Emissions From
Sources of Mercury and Mercury Compounds
September 1993
6. PERFORMING ORGANIZATION CODE
7. AUTHOH(S)
Ms. Robin Jones, Dr. Tom Lapp,
and Dr. Dennis Wallace
(8. PERFORMING ORGANIZATION REPORT NO
9. PERFORMING ORGANIZATION NAME AND AOORESS
Midwest Research Institute
401 Harrison Oaks Boulevard, Suite 350
Gary/ North Carolina 27513
tO. PROGRAM ELEMENT NO.
11. CONTRACT/GRANT NO.
68-D2-0159
12. SPONSORING AGENCY NAME AND ADDRESS
Technical Support Division
OAR, OAQPS, TSD, EFMS (MD-14)
Emission Inventory Branch
Research Triangle Park, North Carolina 27711
IS. SUPPLEMENTARY NOTES
EPA Project Officer: Anne A. Pope
13. TYPE.OF REPORT AND PERIOD COVERED
14. SPONSORING AGENCY CODE
16. ABSTRACT ——————^———^—^—__^______^__—_
To assist groups interested in inventorying air emissions of various
potentially toxic substances, EPA is preparing a series of documents
such as this to compile available information on sources and emission
of these substances. This document deals specifically with mercury
and mercury compounds. Its intended audience includes Federal, State
and local air pollution personnel and others interested in locating
potential emitters of mercury and in making gross estimates of air
emissions therefrom.
This document presents information on (1) the types o-f sources that
may emit mercury and mercury compounds, (2) pxrocess variations and
release points that may be emitted within these sources, and (3)
available emissions information indicating the potential for mercury
and mercury compound releases into the air from each operation.
7.
KEY WORDS ANO DOCUMENT ANALYSIS
DESCRIPTORS
b.lOENTIFIERS/OPEN ENDED TERMS |c. COSATI Field/Croup
Mercury
Mercury Compounds
Air Emissions Sources
Locating Air Emissions Sources
Toxic Substances
8, DISTRIBUTION STATEMENT
Unlimited
19. SECURITY CLASS I Tllif Report I
Unclassified
21. NO. OF PAGES
314
2O. SECURITY CLASS (Tin* page I
Unclassified
22. PRICE
GPA F«nn 2220—1 (R«». 4—77) previous COITION i* oasoeerc
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