%*****y» „ Office o< Air Quality
Environmental Protection Planning and Stanoaroa February 1988
Agency Research Triangle Pi* MC 27711
6EF& Second Review of
New Source
Performance
Standards for
Coal Preparation
Plants
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EPA-450/3-88-001
Second Review of New Source Performance
Standards for Coal Preparation Plants
Emission Standards Division
U. S. ENVIRONMENTAL PROTECTION AGENCY
Office of Air and Radiation
Office of Air Quality Planning and Standards
Research Triangle Park, North Carolina 27711
February 1988
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This report has been reviewed by the Emission Standards Division of the Office of Air Quality Planning and Standards.
EPA, and approved for publication. Mention of trade names or commercial products is not intended to constitute
endorsement or recommendation for use. Copies of this report are available through the Library Services Off ice (MD-35),
U.S. Environmental Protection Agency.-Research Triangle Park NC 27711, or from National Technical Information
Services, 5285 Port Royal Road, Springfield VA 22161.
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TABLE OF CONTENTS
Page
1. SUMMARY
1.1 Best Demonstrated Technology ........................ 1-1
1.2 Industrial Trends ................................... 1-2
1.3 Findings of This Review ............................. 1-3
1.3.1 Coal Dryers and Pneumatic Cleaning
Facilities... ............................... 1-3
1.3.2 Coal Transfer, Handling, and Storage
Sy stems ...... . ............. . ................ 1-3
1.3.3 Monitoring and Recordkeeping ................ 1-4
2. INTRODUCTION ........ . ......................... . .......... 2-1
2.1 Background Information .............................. 2-1
2.2 The Preparation Process ............. ..... ........... 2-5
2.2.1 Plant Feed Preparation.... .................. 2-5
2.2.2 Raw Coal Size Reduction and Screening. ...... 2-7
2.2.3 Raw Coal Cleaning .......... . ........ ." ....... 2-7
2.2.4 Product Oewatering and/or Drying. ...... ..... 2-11
2.2.5 Product Storage and Shipping ................ 2-13
2.3 References ........................................... 2-13
3. CURRENT STANDARDS FOR COAL PREPARATION ................... 3-1
3.1 Affected Facilities ................................. 3-1
3.2 Controlled Pollutants and Emission Levels ........... 3-1
3.3 State Regulations .......................... .. ....... 3-2
3.3,1 Thermal Dryers .......... .... ................ 3-2
3.3.2 Fugitive Sources .................... . ....... 3-3
3 .5 References . . „ ......... . ............ , ...... . . . ..... . . 3-6
4. STATUS OF CONTROL TECHNOLOGY ......... . ..... . ...... . . , ____ 4-1
4.1 Coal Preparation Industry Statistics..,.. ........... 4-1
4.1.1 Number of Plants and Geographic
Distribution ............................. .. . 4-1
4.1.2 Industrial Trends ........................... 4-2
4.1.3 Preparation of Nonbitumi nous Coals .......... 4-5
4.2 Emissions from Coal Preparation Plants .............. 4-6
4.2.1 NSPS Control Techniques ............. . ....... 4-10
4.2.1.1 Thermal Drying ...... . ............... 4-11
4.2.1.2 Pneumatic Cleaning .................. 4-12
4.2.1.3 Storage, Transportation, and
Handling .................................... 4_12
4.2.2 Controls Which Exceed MSPS ................. *. 4-15
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4.3 References 4-17
5. ENFORCEMENT AND COMPLIANCE..; 5-1
5.1 Enforcement Applicability 5-1
5.2 Analysis of NSPS Test Results 5-2
5.3 Monitoring and Recordkeeping 5-2
5.4 References 5-5
6. . COST ANALYSIS 6-1
6.1 Introduction 6-1
6.2 Costs for Controlling Eastern Plants... 6-2
6.2.1 Reported Costs 6-2
6.2.2 Estimated Costs and Cost Comparison 6-2
6.3 Costs for Controlling Western Plants......... 6-5
6.3.1 Reported Costs ,. 6-5
6.3.2 Estimated Costs and Cost Comparison '. 6-5
6.4 Costs for Controlling Fugitive Emission Sources..,.. 6-9
6.5 Cost-Effectiveness of the Present NSPS Controls.,,.. 6-9
6.6 References .... 6-16
7. CONCLUSIONS AND RECOMMENDATIONS 7-1
7.1 Coal Dryers and Pneumatic Cleaning Facilities....... 7-2
7.2 Coal Transfer, Handling, and Storage Systems ,*. 7-2
7.3 Monitoring and Recordkeep ing 7-3
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LIST OF TABLES
Page
Table 2-1. Summary of Physical Coal Cleaning Unit
Operations ........................................ "
Table 2-2. Typical Moisture Content of Products by
Equipment or Process ............................. *'"
Table 3-1 State of Pennsylvania Regulation for Coal ^
Preparation Plant Fugitive Oust Sources .......... 3-a
Table 4-1. Combustion Product Emissions from Well-
Controlled Thermal Dryers ...................... •• Of~l
Table 5-1. Coal Preparation Compliance Test Results
for Thermal Dryers ..... ... ...................... • b"J
Table 6-1. Control Costs for Existing Eastern Coal
Preparation Plants.
Table 6-2. Control Costs for Model Eastern Coal
Preparation Plants
Table 6-3. Control Costs for Sources at a Western Coal
Preparation Plant (Freedom Mine)
Table 6-4. Venturi Scrubber Investment Costs for Fugitive
Euri ssions Control
Table 6-5. Venturi Scrubber Annual 1 zed Costs for Fugitive
Emissions Control ....................... «
Table 6-5. Fabric Filter Investment Costs for Fugitive
Emissions Control..
Table 6-7. Fabric Filter Annual 1 zed Costs for Fugitive
Emi ssions Control ................................ 6°13
Table 6-3. Cost Effectiveness Calculations for Particulate
Control from Dryers at Existing Eastern Coal
Preparation Plants ............................... 6"14
Taole 5-9, Cast Effectiveness Calculations for Existing
Western Coal Preparation (Beulah County, MO) ..... 6-15
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LIST OF FIGURES
Figure 4-1. Potential Sulfur Dioxide Emissions (1 OS/mill ion
Btu) 12,500 Btu/lb Coal. 4-8
Figure 6-1. Eastern Coal Preparation Plants Investment
Cost vs Air Volume 6-6
Figure 6-2. Eastern Coal Preparation Plants Annualized
Cost vs Air Volume » 6-7
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1. SUMMARY
The objective of this report is to review and determine the need for
revision of the NSPS for coal preparation plants. The review includes
new developments in emission control technology, coal preparation process
technology, projected growth, and other considerations affecting air
emissions in the industry.
The new source performance standards (NSPS) for the coal preparation
industry were promulgated by the Environmental Protection Agency (EPA) on
January 15, 1976. These standards affect thermal dryers, pneumatic co^
cleaning equipment, coal processing and conveying equipment, coal storage
systems, and coal transfer and loading facilities. Affected facilities
are those facilities which commenced construction or modification after
October 24, 1974.
The NSPS were reviewed for the first time in 1981. That review
concluded that, since best demonstrated control technology had not changed
since the regulations were originally prcmul gated, tne standards should
remain unchanged. This is the second review of the NSPS. It covers the
period from 1980 through 1986.
1.1 BEST DEMONSTRATED CONTROL TECHNOLOGY
The current NSPS specifies emission limits for thermal dryers and
pneumatic coal cleaning equipment based on particulate concentration loadings.
Emissions from thermal dryers are not to contain particulate matter in
excess of 0.31 grains per dry standard cubic foot and shall not exhibit
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20 percent or greater opacity. Emissions from pneumatic coal cleaning
equipment are not to contain parti oil ate matter in excess of 0=018 grains
per dry standard cubic foot and shall not exhibit 10 percent or greater
opacity.
No changes have occurred in control technology for thermal dryers
and pneumatic cleaning equipment since promulgation of the standards of
performance. The best demonstrated technology (SOT) for thermal dryers
consists of primary control using centrifugal collectors. Secondary
control is accomplished by the use of high-efficiency venturi scrubbers.
301 for pneumatic coal cleaning equipment consists of primary control
using centrifugal collectors and secondary control using fabric filtration
The current NSPS regulates fugitive emissions from coal processing
and conveying equipment, coal storage systems, and coal transfer and
loading systems. Emissions from these sources shall not exhibit 20
percent or greater opacity. This has historically been accomplished
through the use of wet suppression and enclosure of sources of potential
fugitive partial! ata emissions. During this review, however, several coal
preparation plants *ere found to be controlling sources of fugitive
emissions by enclosing the source and ducting the emissions to a control
device.
1.2 INDUSTRIAL TRENDS
The production of coal in the United States has been growing at an
average annual rate of about 3 percent since promulgation of the NSPS.
The economics of coal preparation technology is resulting in declining
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use of thermal drying in favor of mechanical dewatering for Eastern coals.
However, the practice of thermally drying coal at preparation plants has
been declining. Western coals are not dried either thermally or mechanically
In 1974, a growth rate of nine thermal dryers per year was estimated.
Actual construction of thermal dryers averaged three per year during the
period covered by the previous review (1974-1979), and has averaged only
two per year during the period covered by the current review (1980-1986).
The use of thermal drying of coal is expected to continue to decline.
The use of pneumatic coal cleaning equipment has also been declining and
no new pneumatic coal cleaning facilities are projected.
1.3 FINDINGS OF THIS REVIEW
1.3.1 Coal Dryers and Pneumatic Cleaning Facilities
There has been general compliance with the current NSPS for thermal
dryers and pneumatic coal cleaning equipment with achievability of existing
standards adequately demonstrated.
1.3.2 Coal Transfer. Handling, and Storage Systems
Technology being applied to the control of emissions from coal
transfer, handling, and storage systems appears to be changing. These
sources have historically been controlled by wet suppression or enclosure
to prevent excessive fugitive emissions. More recently, however, several
well-controlled coal preparation plants have enclosed sources of fugitive
emissions and ducted the emissions to a control device. Where this
technology is employed, the opacity of emissions from the source and the
control device is generally substantially less than the 20 percent required
by the NSPS.
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1.3.3 Monitoring and Recordkeepinq
The NSPS currently requires the owners or operators of coal preparation
plants to continuously monitor the pressure of the water supply to the
venturi scrubber which controls emissions from thermal coal dryers. This
requirement appears to be unnecessary. This review found that venturi
scrubber performance can be adequately determined by monitoring the
pressure drop across the scrubber, which is also a requirement of the NSPS.
This review also found that there is no current reporting requirement
for excess emissions. Further, it was found that the pressure drop across
the venturi scrubber is a good indicator of scrubber performance and that
this parameter could be used as an indicator of excess emissions.
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2. INTRODUCTION
On October 24, 1975 (39 FR 37922), under Section 111 of the Clean
Mr Act, the Environmental Protection Agency (EPA) proposed standards of
performance for new and modified coal preparation plants. In accordance
with Section 111 of the Act, as amended, these regulations were promulgated
on January 15, 1976, prescribing standards of performance for coal prepa-
ration pi ants.1 The regulations applied to thermal dryers, pneumatic coal
cleaners, coal processing and conveying equipment, coal storage systems,
and coal transfer and loading systems, the construction or modification
of which commenced after October 24, 1974.
The Clean Air Act Amendments of 1977 require the Administrator of the
EPA to review and, if appropriate, revise established standards of per-
formance for new stationary sources at least every 4 years.2 The standard
was previously reviewed in 1980. That review concluded that the regulations
should remain unchanged.3 The purpose of this report is to again review
and assess the need for revision of the existing standards for coal
preparation plants based on developments that have occurred between 1980
and 1986, or are expected to occur within the coal preparation industry.
The information presented in this report was obtained from reference
literature, discussions with industry representatives, trade associations,
control equipment vendors, SPA Regional Offleas, and State agencies.
2.1 BACKGROUND INFORMATION
Coal preparation is a series of processes which has the overall
objective of improving the characteristics of mined coal by removing
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certain contaminants and changing its physical properties to meet market
demands of industry. The degree of preparation varies widely, and the
processes range from simple mechanical removal of rock and dirt to
complex coal beneficiation plants which remove chemical contaminants
(e.g., sulfur) which may produce pollution problems (e.g., SOj) at some
point of end use. The type of cleaning process and the extent of cleaning
depends on the type of coal, the method of mining, contaminants, and the
end use of the coal. Some characteristics of coal which may be
altered by coal preparation include the following:
Size
0 Mineral content
0 Sulfur content
" Foreign materials
0 Surface moisture
The relative amount of contaminants, the manner in which they are part
of the coal structure, and the degree to which they can be reduced, vary
widely with different coals.
Almost all of the coal mined in the United States is subject to some
type of preparation process. Presently, all domestic commercial coal
preparation plants handling bituminous coal use physical coal cleaning
techniques which are primarily designed to remove mineral matter. Mineral
matter forms ash when coal is burned. These pnysical coal cleaning
techniques also increase the energy content of the coal by reducing moisture
and other non-combustibles. Run-of-the-mine (ROM) coal is physically
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cleaned by crushing in several stages to the point at which a portion
of the mineral impurities are separated from the coal structure. The
mineral and coal fragments are then separated by dry and/or wet techniques
which utilize the differences in the specific gravity OP surface properties
of the particles. Western coal, mainly subbituminous and lignite coals, are
strip mined and are not treated by wet techniques. Strio mines commonly
contain thick deposits of coal covered by foreign material called overburden
(roclc and soil), which is removed almost completaV/. The coal then removed
and reduced in size and classified as needed. Though almost all mined coal
is crushed and sized in a coal preparation process, only about 35 percent
of coal mined in the United States undergoes physical cleaning.4
The existence of State and Federal sulfur dioxide (S02) emission
regulations has created interest in the sulfur reduction potential of
the coal preparation process. Sulfur found in coal is normally chemically
combined with iron as FeS2 (pyritic sulfur) which is impregnated in the
coal, or as an organic compound which is chemically bound to the coal
(organic sulfur). The organic sulfur is part of the coal itself and cannot
be removed unless the chemical bonds are broken. The amount of organic sulfur
present, therefore, defines the theoretical lowest limit to which the sulfur
can be removed by physical methods. In American coals, the organic sulfur
ranges from about 20 to 80 percent of the total sulfur, and has a mean value
of about 50 percent of the total sulfur. 5
Several attempts have been made to liberate the pyritic sulfur by
the effect of crushing, i.e., reduction in size and subsequent treatment
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based on the density of the components. One system, known as the
Multi-Stream Coal Cleaning System (MCCS), selectively removes the pyrltic
sulfur from the coal stream, dramatically reducing the sulfur content
of the coal. It 1s designed to provide low-sulfur (2.24 percent sulfur)
coal to fuel two existing 600 megawatt steam generation units at the
adjacent power plant as well as ultra-low-sulfur (0.88 percent sulfur)
coal for a 650 megawatt unit. The selected design utilizes a broad
spectrum of conventionally applied coal cleaning equipment, working to
its best advantage on a preprocessed feedstock. The MCCS has been
operating successfully since 1984.6
Chemical coal cleaning processes are also being developed to provide
improved techniques for desulfurizing coal employed for steam generation
and metallurgical purposes. These processes are intended to renrave the
organic sulfur. Chemical coal cleaning processes vary substantially due
to the different chemical reactions which can be used to remove the sulfur
and other contaminants from the coal. Chemical coal processes usually
entail grinding the coal into small particles followed by treatment using
acid, alkaline, and oxidation reaction methods. The report on the previous
(1980) 4-year review estimated that several chemical processes could be
ready for commercial demonstration In 5 to 10 years.7 That estimate
proved to be optimistic, and commercial demonstration of chemical coal
cleaning still appears to be 5 to 10 years away.8
The specific intent of chemical coal cleaning Is to produce desulfurized
coals for use in complying with S02 emission standards. If inexpensive
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processes can be developed that reduce sulfur content as well as achieve
high Btu yields, the vast eastern and midwestern coal reserves would
hold greater potential use to industry because compliance with regulations
which govern SOa emissions could be more readily and economically
achieved. Because chemical cleaning is still in the development stage, it
is uncertain which processes will prove commercially viable. This report
deals exclusively with the available technology of physical coal preparation.
2.2 THE PREPARATION PROCESS^
The physical preparation of coal may be categorized into five general
processes:
1. Plant feed preparation.
2. Raw coal size reduction and screening.
3. Raw coal cleaning (removal of impurities, including ash and pyritel
4. Product dewaterfng and/or drying.
5. Product storage and shipping.
2.2.1 Plant Feed Preparation
The first step in the coal preparation process is the delivery of
run-of-the-mine (ROM) coal to the plant site. Coal is transported by
railroad cars, trucks, or conveyors from both surface and underground
mines. When ROM coal is delivered to the preparation site, it is
dumped into a surge bin or surge-feeder. The coal is then processed by
a ROM scalper to remove large pieces of coal and rock. The ROM scalper
is usually a heavy-duty, mechanically vibrated, single deck, inclined
screen.
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The second step is size reduction, which is done 1n coal breakers
or crushers. There are two fundamental object1v.es for the reduction of
the size of coal: to reduce it to sizes suitable for cleaning or further
reduction, and to meet market specifications for certain sizes. Since
production of fines is considered undesirable, breakers and crushers
are designed to produce minimal amounts of undersize material. ROM
coal is broken into increasingly smaller sizes by staged reduction. The
first stage, primary breaking, reduces the raw coal to 4 to 8 Inches.
For metallurgical coal the various sizes are then screened and sent to
washing units or to secondary crushers which reduce the product to a
top size of 1.75 inches. Subbituminous and lignite coals are not
treated in washing units. The final step In the plant feed preparation
process is storage of the raw coal.
The storage of raw coal has become an increasingly important
operation in new, large coal preparation facilities because it:
* limits interruptions of feedstock to the preparation plant,
9 improves efficiency by allowing a controlled feed rate, and
a facilitates 1n blending various ROM coals to produce the
desired properties of the feedstock.
Raw coal can be stored either in open areas, closed bins, or
partially or entirely closed slot storage facilities known as barns.
Though open outside storage is usually chosen, there are drawbacks to
this method. Outside coal storage is a potential environmental problem
due to wind and rainfall erosion. Winds remove particulate matter from
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the storage pile, and rainfall can also leach pollutants from this pile
which end up in "run-off" water. The storage of coal in closed bins or
slot storage facilities, however, minimizes the potential for airborne
pollutants and run-off. Various types of bunkers, silos, and bins are
available. Storage bins are usually cylindrical in shape and constructed
of steel or concrete.
2.2.2 Raw Coal Size Reduction and Screening
Raw coal sizing generally consists of two stages, primary and secondary,
that result in the separation of the coal into three sizes: coarse, inter-
mediate, and fine. Primary sizing is typically accomplished hy screens
that separate coal into coarse and intermediate fractions. The coarse
fraction is reduced in size as necessary and returned to the primary
sizing stage. The second sizing stage is generally accomplished by wet
(in the case of bituminous coal) or dry vibrating screen. This stage
separates the fines from the intermediate fraction and directs the resultant
product to the raw coal cleaning operation.
The sizing and screening of coal and its transfer from one operation
to the next are sources of fugitive particulate emissions.
2.2.3 Raw Coal Cleaning
The raw coal cleaning operation.determines product quality. Although many
different coal cleaning techniques exist, most processes are based upon gravity
separation methods. The decision concerning which separation process should
be used is generally based on the size grouping (fine, intermediate, coarse)
of the raw coal. Table'2-1 summarizes the types of equipment used for raw coal
cleaning.
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TABLE 2-1. SUMMARY OF PHYSICAL COAL CLEANING UNIT OPERATIONS
Unit Operation
Description
Remarks
Hydrocyclones
Humphrey spiral
Launder-type coal
The separating mechanism is described
as taking place in the ascending
vortex. The high and low specific
gravity particles moving upward in
this current are subjected to centri-
fugal forces effecting separation.
Coal-water slurry is fed into a spiral
conduit. As it flows downward, strati-
fication of the solids occurs with the
heavier particles concentrated in a
band along the spiral. An adjustable
splitter separates the stream into
two products - a clean coal and the
middlings.
Raw coal is fed into the high end of a
trough with a stream of water. As the
stream of coal and water flows down the
Incline, particles having the highest
settling rate settle into the lower
strata of the stream. These are the
middling or refuse particles. The clean
coal particles gravitate into the upper
strata before separation.
If maximum pyrite reduction and
maximum clean coal yield are to be
obtained, supplemental processes
such as cyclone classifying, fine
mesh screening and froth flotation
are necessary (on stream process).
Hydrocyclones are presently used
in the United States to clean
flotation-sized coal, but can be
used for coarse coal.
Has shown significant ash and
sulfur reduction on Middle
Kittanning coal.
Three types of launders are
recognized based upon mode of
transport. Sizes: 4 mesh to
3 Inches.
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TABLE 2-1. SUMMARY OF PHYSICAL COAL CLEANING UNIT OPERATIONS (Cont.)
Unit Operation
Description
Remarks
Pneumatic
Froth flotation
Coal and refuse particles are stratified
by means of pulsating air. The layer
of refuse formed travels forward into
pickets or wells from which it is with-
drawn. The upper layer of coal travels
over the refuse and is removed at the
opposite end.
A coal slurry is mixed with a collector
to make certain fractions of the
mixture hydrophilic. A frother is
added and finely disseminated air
bubbles are passed through the mix.
Air-adhering particles float to the
top of the remaining slurry and then
are removed as concentrate.
Most acceptable preparation method
from the standpoint of delivered
heating value cost. Sizes: up to
0.25 inches.
Froth flotation is used to reduce
pyrite in English coals; the
flotation of coal refuse to obtain
salable pyrite is uneconomical in
view of today's poor sulfur market;
if ethylxanthate is used as the
collector, it is absorbed onto coal
pyrite in such a manner as to make
it ineffective for flotation.
Sizes: 14 to 325 mesh.
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TABLE 2-1. SUMMARY OF PHYSICAL COAL CLEANING UNIT OPERATIONS (Cont.)
Unit Operation
Description
Remarks
Jigging
Tables
Dense media
A pulsating fluid stratifies coal
particles in Increasing density from
top to bottom. The cleaned coal is
overflowed at the top.
Pulverized coal and water are floated
over a table vibrating In a recipro-
cating motion. The lighter coal
particles are separated to the bottom
of the table, while the heavier,
larger, impure particles move to the
sides.
Ccal is slurried in a medium with a
specific, gravity close to that at
which the reparation is to be made.
The lighter, purer coal floats to the
top and is continuously skimmed off.
Most popular and least expensive
coal washer available, but may not
produce the desired separation.
Sizes: 6 mesh to 3 Inches.
Sizes: 100 mesh to 0.25 inches.
Advantages: Ability to make sharp
separations at any specific gravity
within the range normally required;
ability to handle wide range of
sizes; relatively low capital and
operating costs when considered in
terms of high capacity and small
space requirements; ability to
handle fluctuations in feed quantity
and quality. Sizes: 28 mesh to
8 inches.
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2.2.4 Product Dewatering and/or Drying
The wet types of coal cleaning operations require some type of product
dewatering and/or drying stage. Removal of excess moisture from coal decreases
shipping costs, increases the heating value of the coal, and prevents freezing
problems in cold climates. Moisture reduction can be accomplished by either
mechanical or thermal drying processes. Table 2-2 shows the product coal
moisture ranges which can be achieved by various dewatering and drying methods.
The decision of which moisture reduction scheme to utilize is primarily
dependent on coal particle size. Coarse particles greater than 0.25 inch
offer comparatively small surface areas for moisture adhesion and can be
dewatared by mechanical means to S percent moisture content or less.
Fine coals, 0.5 inch x 23 mesh, have a considerably larger surface area
in proportion to weight and require more sophisticated mechanical dewatering
techniques to reduce moisture content to below 10 percent. Advanced
dewatering techniques include processes such as high performance centrifuges
and vacuum filters. Very fine coals, 0.25 inch x 28 mesh, represent the
greatest problem, and often may only be adequately dried by the thermal
(evaporative) means as a final step. The energy requirements of dewatering
and drying are directly related to the size of the feed and the percent
moisture reduction desired, and can be very high. Thermal drying is the
major air pollutant emission source for thermally dried coal. The emissions
consist of particulates, sulfur dioxide, and nitrogen oxides generated
during the combustion of coal to provide the hot gases for drying of the
coal, as well as entrained small coal particles.
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TABLE 2-2. TYPICAL MOISTURE CONTENT OF PRODUCTS BY EQUIPMENT OR PROCESS
Type of Equipment/Process
Discharge of Product
Dewatering screens
Centrifuges
Filters
Hydraulic cyclones
Static thickeners
Thermal dryers
Oil agglomeration processes
8 to 20 percent moisture
10 to 20 percent moisture
20 to 50 percent moisture
40 to 60 percent solids
30 to 40 percent solids
6 to 7.5 percent moisture
3 to 12 percent moisture
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2.2.5 Product Storage and Shipping
Coal preparation plants must be capable of providing specific
quantities of cleaned coal at specified times. Sometimes it is not
feasible to load clean coal at the rate of production of the coal
preparation plant. As a result, clean coal storage has become an
economic necessity. Several important reasons for storing clean coal
are:
to quickly and economically load unit trains, barges, and other
intermittent bulk transport conveyances;
0 to facilitate the attainment of maximum product uniformity;
and
to eliminate the dependency on preparation plant production.
Cleaned coal may be stored in open, uncontrolled storage piles or in enclosed
silos or bins. In contrast to open storage facilities, enclosed storage
facilities eliminate blowing dust and wind losses as well as protect the
clean coal from the elements.
2.3 REFERENCES:
1. United States Environmental Protection Agency. Code of Federal
Regulations, Title 40, Part 60. Washington, O.C. Office of
the Federal Register. January 15, 1976.
2. United States Congress. Clean Air Act, as amended, August 1977.
42 U.S.C. 1857 et. seq. Washington, D.C. U.S. Government Printing
Office. November 1977.
3. U.S. Environmental Protection Agency. A Review of Standards of
Performance for New Stationary Sources - Coal Preparation Plants.
EPA Publication No. EPA-450/3-30-022. December 1980. p. 6-5.
4. Electric Power Research Institute. Report Summary. Coal-Cleaning
Plant Refuse Characterization. Report No. EPRI CS-4095s. June 1985.
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5. Leonard, J. W., and Mitchell, 0. R. Coal Preparation. New York,
The American Institute of Mining, Metallurgical, and Petroleum
Engineers, Inc. 1968, pp. 1-44 through 1-48.
6. Telecon. Beck, Lee, U.S. Environmental Protection Agency, with
Harrison, Clark, Electric Power Research Institute, June 27, 1986.
Multi-Stream Coal Cleaning System.
7. Reference 3, p. 2-3.
8. Telecon. Beck, Lee, U.S. Environmental Protection Agency, with
Kilgroe, J.D., U.S. EPA, October 29, 1986. Coal Cleaning Research.
9. Reference 3, pp. 2-3 through 2-12.
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3. CURRENT STANDARDS FOR COAL PREPARATION .
3.1 AFFECTED FACILITIES
The existing standards of performance apply to coal preparation plants
processing more than 200 tons of coal per day. The specific processes
affected by the new source performance standard (NSPS) are thermal
dryers, pneumatic coal cleaning equipment (air tables), coal processing
and conveying equipment (including breakers and crushers), coal storage
systems, and coal transfer and loading facilities. The standards
governing thermal dryers and pneumatic coal cleaning equipment apply
only to facilities processing bituminous coal. The regulation limiting
emissions from coal processing and conveying equipment, coal storage
systems and coal transfer and loading facilities, however, applies to
the processing of all types of coal. Open coal storage piles are
currently excluded from the definition of coal storage systems.1'2
. 3.2 CONTROLLED POLLUTANTS AND EMISSION LEVELS3
The coal preparation plant pollutant controlled by the NSPS is
particulate matter. The standards are as follows:
0 Thermal dryer. Exhaust gases discharged to the atmosphere shall
not contain particulate matter in excess of 0.070 grams per dry
standard cubic meter (g/dscm) or 0.031 grains per dry standard
cubic foot (gr/dscf), and shall not exhibit 20 percent or greater
opacity.
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0 Pneumatic coal cleaning equipment (air tables). The gases emitted
to the atmosphere shall not contain particulate matter in excess
of 0.040 grams per dry standard cubic meter (0.018 grains per dry
standard cubic foot), and shall not exhibit 10 percent or greater
opacity.
0 Other facilities. Gases emitted into the atmosphere from any
coal processing and conveying equipment, coal storage system, or
coal transfer and loading facility shall not exhibit 20 percent
or greater opacity.
3.3 STATE REGULATIONS
All of the States surveyed in this study enforce the NS?S for new
coal preparation plants. However, most States do not have regulations
specific to existing coal preparation plants. These facilities are usually
regulated by general process weight regulations which base the allowable
emissions on the process throughput, regardless of the material being
processed.
3.3.1 Thermal Dryers
State standards governing existing preparation plants are generally
less stringent than the Federal NSPS. The only possible exceptions are for
plants with very large capacities. In Arizona, for instance, using the
allowable emissions formula for existing plants inside the Phoenix/Tucson
Region, a 500 tons per hour thermal dryer would have a maximum allowable
particulate emission rate of 46.78 pounds per hour. Based on average
emission factors for fluid bed dryers with high efficiency venturi-type
wet scrubbers for secondary control, the corresponding particulate
3-2
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concentration would be 0.028 grains per dry standard cubic foot.5 This
is slightly less than the thermal dryer NSPS.
3.3.2 Fugitive Sources
As with the regulations for thermal dryers, all States enforce the
NSPS for new plants, and most State regulations for existing plants are not
as stringent as the NSPS. There are, however, some notable exceptions.
The State of Kentucky requires covering of trucks which transport
material, including coal, which may become airborne. The State also requires
that roadways inside the plant be paved and "no visible fugitive dust
emissions beyond the lot line of the property."6
The State of West Virginia requires, in addition to the NSPS, that
roads inside the plant and access roads owned by the plant be controlled
for fugitive emissions by paving or other suitable measures.7
The State of North Dakota applies process-weight regulations to coal
preparation plants. Facilities in that State process lignite coal which
is not dried, so the regulations apply only to fugitive sources such as
crushers and transfer, loading, and storage facilities. Because of the
large amount of material handled by these systems, the process-weight
regulations are relatively restrictive and the systems are frequently
controlled by total enclosure and fabric filtration. The resulting
control is far greater than the limitation of 20 percent opacity required
by the NSPS.
Pennsylvania requires best available technology (BAT) for fugitive
dust sources for any new coal preparation plants or additions to existing
ones. Sources such as coal transfer to trucks and roadways associated
with surface mines have been delegated to the Bureau of Mining Regulations.
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The minimum BAT requirements for fugitive dust emissions from coal preparation
plants are a function of plant rated annual coal throughput and proximity to
private residences. The Pennsylvania fugitive BAT standards are depicted
in Table 3-1.
Probably the most stringent State regulations for fugitive emissions
from coal preparation plants are those adopted by the State of California,
which are applied primarily to coal shipping terminals in that State.
The California regulations require the following control techniques to
be used:^
0 Enclosing all conveyor transfer points and coal receiving hopper
areas,
0 Providing in-draft air to enclosures (approximately 150 fpm air
velocity through opening) and exhausting to a fabric collector.
0 Particulate grain loading from each fabric collector may not
exceed 0.005 - Oa01 gr/scf.
0 Installing water suppression systems and using chemical surfactants
to minimize fugitive emissions from unenclosed sources.
0 Reducing the falling distance of the coal during loading by using
telescopic chutes.
0 Enclosing the stacking area.
0 Installing-wind barriers to reduce dust entrainment caused by
strong winds.
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TABLE 3-1. STATE OF PENNSYLVANIA REGULATION FOR COAL
PREPARATION PLANT FUGITIVE OUST SOURCES
Annual Coal
Throughput
(T/yr)
> 500,000
<_ 500,000
<_ 500,000
£ 200,000
Proximity to
Residences
N/A
<_ 1/4 mile
> 1/4 mile
N/A
Coal
Storage
A+8+C+0
A+8+C+Q
4+8+0
D
Conveyors
E
F
F
-
Crushers/
Screens
G+H+I
G+H+I
G+H
G
Loading/
Unloading
J+K
L
L
L
Roadways
N+O+P
N+O+P
N+O+P
M+P
MISC.
Q
q
T
^
KEY TO TABLE 3-1.
Coal Storage
A. Radial or tube stacker with air canon or other device to prevent operational
problems in the winter.
3. Use of existing and/or man-made wind barriers.
C. Use of permanent elevated surfactant treated water/oil sprays or watar truck wit.i
pressurized spray gun for stockpile control.
0. Storage silos with bin vent collector (required for thermally dried coal).
Coal Conveyors
E. Fully enclosed.
F. Partially enclosed.
Crushers and Screens
G~IEnclosure of rotary breakers and crushers.
H. Enclosure of screens and transfer points.
I. Use of winterized surfactant treated water/oil sprays at appropriate points.
Loading/Unloading of Coal
37Underground reclaim tunnels under stockpiles.
K. elevated rai1/barge/truck loadout with telescopic cnute.
L. Front end loaders.
Roadways
R". Plant roadways must be delineated by paving or by periodic chipping.
N. Plant entrance roadway must be paved for the first 500 feet and routinely swept;
remainder must be delineated by paving or period chipping.
0. Road dust control by road sweeper (if paved) and use of water sprays, oils, or other
surfactants including 250 feet of public highway on either side of plant access road.
P. Tarping of all trucks plus posted notice of tarping requirement.
Miscellaneous
$~. Upwind/downwind dustfall monitoring at the request of the State.
3-5
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3.4 REFERENCES:
1. United States Environmental Protection Agency. Code of Federal
Regulations. Title 40, Part 60. Washington, D.C. Office of
the Federal Register. January 15, 1976.
2. Burke, J. R., N. J. Kulujian, and Y. M. Shah. Inspection Manual
for Enforcement of New Source Performance Standards: Coal
Preparation Plants. U.S. Environmental Protection Agency,
Washington, D.C. Publication No. EPA-340/1-77-022. November 1977.
p. 156.
3. Reference 1.
4. U. S. Environmental Protection Agency. Code of Federal Regulations,
Title 40, Part 60. Washington, D.C. Office of the Federal Register.
January 15, 1976.
5. U.S. Environmental Protection Agency. Background Information for
Standards of Performance: Coal Preparation Plants Volume I:
Proposed Standards. Research Triangle Park, N.C. Puolication
No. EPA-450/2-74-02U. October 1974. p. 9.
6. State of Kentucky Department of Natural Resources and Environmental
Protection. Regulation No. 401 KAR 63:010. Fugitive Emissions,
pp. 142.
7. West Virginia Administrative Regulations. Chapters 16-20. Series V.
Section 5, paragraph 5.02,
8. State of Pennsylvania Department of Environmental Regulation. Best
Available Technology for Coal Preparation Plants. Fugitive Dust
Sources. Pernit Manual 127,12(a)(5):27. July 1985.
9. Letter from Shiroma, G., State of California Air Resources Board, to
Georgieff, N. T., U.S. EPA. December 1985.
10. National Environmental Development Association. Air Pollution Control
Growth and Clean Air, Assessment of Federal Law. 1978.
3-6
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4. STATUS OF CONTROL TECHNOLOGY
4.1 COAL PREPARATION INDUSTRY STATISTICS
4.1.1 Number of Plants and Geographical Distribution
According to data obtained from the Energy Information Adminstration
and from States, at least 359 new coal preparation plants were put in
operation between 1980 and 1985.1.2,3,4,5 This does not take into account
plants which may have become subject to the NSPS via the modification/
reconstruction provisions.
Though the location of these new plants is widely distributed,
two-thirds are located in Kentucky, West Virginia, and Pennsylvania.
These States supply bituminous coal, which is used as metallurgical coal
for coke making and For combustion in utility boilers. The Western
States, such as Montana and Wyoming, are sources of subbituminous coal.
Texas and North Dakota are sources of lignite coal.
The last review of the NSPS indicated that approximately 438 coal
preparation plants were operating in the United States in 1979.6 This
number is believed to be erroneous. The reference for it (1979 Keystone
Coal Industry Manual, page 1311) makes no such claim. According to the
Energy Information Administration, there were 1017 coal preparation plants
operating in the United States in 1980, and 1378 coal preparation plants
operating in the United States in 1985.7 A possible explanation for the
mistaken number of coal preparation plants cited in the previous study is
a listing of mechanical coal cleaning plants. The manual lists about 500
mechanical coal cleaning plants.3
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4.1.2 Industrial Trends
During the last review of the NSPS, projections were made that 40
new or modified facilities would be in operation by 1985. As stated above,
this estimate was exceeded by a wide margin. In the State of Kentucky
alone, permits were issued for the construction of 208 new coal preparation
pi ants.9 The daily production capacity of each of these plants was in
excess of 200 tons. The reason for this gross misprojection of new
facilities is unknown. The estimate given in the previous study was
based on a projected increase in annual production of domestic coal to
about 1 billion tons by 1985. Actual production achieved in 1985 was
about 900 million tons or 90 percent of that projected in the previous
study. Possibly the earlier study assumed that increased production
would be accomplished by fewer plants with very large production
capacities. The study may also have neglected or underestimated the
inpact of plant closures on new plant construction.
The construction of new coal preparation plants is, of course,
directly linked to increases in coal production. The Energy Information
Administration projects annual coal productions to increase to 1.1
billion tons by 1990 and to 1.2 billion tons by 1995. For the 1985-
1995 decade, this translates to an average annual growth rate of 3.1
percent.10
Annual coal production in 1985 exceeded 1980 annual production by
128 million tons. Coupling this increase in coal production with the
number of coal preparation plants constructed during that time period
4-2
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(359) produces a factor of 2.8 plants per minion tons of increased
annual production. Application of this factor to the increase in annual
production projected by 1995 (300 million tpy greater than 1985 pro-
duction),^ a crude projection can be made of 84 new plants per year for
that 10 year period. While this method does not take into account such
unknown factors as the current relationship of actual production to
production capacity, it does illustrate the potential for substantial
growth in the number of new plants over the next decade.
While production and preparation of coal is expected to increase,
the practice of thermal drying is declining. When the MSPS became effective
in October 1974, EPA projected a growth rate of 9 thermal dryers per
year. However, only 17 new dryers were built during the period covered
by the previous MSPS review (1974-1980), which amounts to less than 3 new
dryers per year. During the period covered by the current review (1980-1985),
only 10 new dryers were found to have been constructed. This is only
2 per year. The State of Kentucky, which experienced the greatest amount
of new plant construction during the period of 1980-1985 (208 construction
permits awarded), reported that no thermal dryers were constructed in
that State during the subject 5 year period.12
The principle reason behind the general reduction in thermal dryers
is that the energy costs associated with thermal drying are substantial.
Energy savings associated with the elimination of thermal dryers approach
1 percent of total coal production.1-3 For example, for a facility pro-
cessing 500 tons of coal per hour, the eqivalent of 5 tons of coal is
necessary to operate the dryers.
4-3
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Declining use of thermal drying has led to a greater dependence on
mechanical dewatering. Over the past few years, several sophisticated
mechanical drying processes have been introduced to the industry. The
new processes are able to achieve greater reduction in surface moisture
content than previously possible by mechanical methods. This provides
a significant advantage because the energy benefits of removing excess
moisture, in terms of avoiding transportation and evaporation penalties,
are much greater than the energy requirements for mechanical dewatering.
The trend towards improving this technology is expected to continue,
with emphasis being placed on reducing the surface moisture of fine
siza coal particles,
Another significant processing trend has been in the area of chemical
cleaning technology. As many processes are still in the pilot plant or
development stage, performance and cost comparisons are relatively uncertain
at this time. These procesess vary greatly in their approach because of
the varied reactions which can be used to effectively remove sulfur and
other reactive impurities in the coal. Most chemical processes under
development ramove over 90 percent of the pyrite sulfur. In addition,
several of the processes reportedly remove up to 40 percent of the organic
sulfur.14 These new processes have been developed to maximize the reduction
of sulfur (pyrite) in metallurgical coals and boiler fuels which must
comply with sulfur dioxide ($02) emission regulations.
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4.1.3 Preparation of Nonbitunrinous Coal
Coal drying, pneumatic cleaning (air tables) and beneficiation
operations in the United States are applied almost exclusively to
bituminous coals. However, the opacity provisions of the NSPS apply to
the handling of all kinds of coal, regardless of type, as long as the
amount of coal processed exceeds 200 tons per day.
Anthracite production in the United States was less than 6 million
tons in 1985. This represents less than 1 percent of the total United
States annual coal production. The preparation prcoass for anthracite
is comparable to that of bituminous coal preparation. The principle
consumer of anthracite is the metallurgical industry.
The production of lignite and other subbituminous coals was 265
million tons in 1985,15 and production and use of subbituminous coals is
expected to increase. The Energy Information Administration projects
that annual production of Western Coal (predominently subbituminous) will
increase at an average rate of 1.6 percent greater than the growth rate
projected for Eastern coal production over the next 10 years.10
The largest deposits of subbituminous coals are found in Montana,
Wyoming, Colorado, New Mexico, and Arizona. As with lignite, most
subbituminous coal seams are relatively free of impurities. Preparation
generally consists of crushing to the extent necessary to facilitate
transporation and handling. Because the moisture content is mostly
inherent, subbituminous coals appear very dry and dusty during handling
4-5
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and transporation.17 Because of the potential that exists for the
utilization of subbituminous coal, fugitive emissions from the preparation
of the coal may increase in significance.
4.2 EMISSIONS FROM COAL PREPARATION PLANTS
There are four principle sources of air pollution in the coal
preparation process:
1. thermal drying;
2. pneumatic cleaning;
3. crushing and sizing; and
4, coal storage, transportation, and handling.
Air emissions from thermal dryers include particulates from the
drying process as well as particulates from the coal-fired furnace that
supplies the drying gases.
Uncontrolled particulate emissions from fluid bed thermal dryers have
been estimated at 20 pounds per ton of coal dried.18 Based on this factor,
a 500 tons per hour furnace would have an controlled emission rate of
10,000 pounds per hour. For a 3,000 hour operating year, uncontrolled
annual particulate emissions would be 15,000 tons per year.
Gaseous emissions from thermal dryers include carbon monoxide (CO),
carbon dioxide (COe) hydrocarbons (HC), sulfur dioxide (S02), and nitrogen
oxides (NOXK All of these are furnace combustion products. Table 4-1
shows typical uncontrolled emission ranges of some of the gaseous emissions.^-9
4-6
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TABLE 4-1. COMBUSTION PRODUCT EMISSIONS FROM THERMAL DRYERS
Pollutant
NOX
CO
HC (as methane)
Emission rate
lb/106 Btu
0.39 to 0.68
<0.30
0.07 to 0.35
Concentration
ppm
40 to
<50
20 to
70
100
The emissions of S02 from thermal dryers are a function of the
sulfur content of the coal burned in the combustion furnace. Figure 4-1
illustrates this relationship for bituminous coal rated at 12,500 Btu
20
per pound. Using this relationship, potential emissions of SO? may be
calculated for thermal dryer furnaces. For example, a typical furnaca
using coal with 1 percent sulfur would be estimated to emit 1.6 pounds
of $62 per million Btu. Based on this estimate, a 100 million Btu per
hour furnace has the potential for emitting 160 pounds of S02 per hour.
Annual emissions of S02 (based on a 3,000 hour operating year) would be
240 tons per year.
Actual S02 emission levels from thermal dryers may not be as high as
those estimated using Figure 4-1. Source tests conducted by EPA have
recorded emission rates from thermal dryers in the range of not detectable
to 0.09 pound S02 per million Btu.21 Based on the highest measurement,
a 100 million Btu per hour furnace would have a maximum S02 enission rate
4-7
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Potential Sulfur Dioxide Emissions
(Ibs/million Btu) for 12,500 Btu/lb Coal
Weight Percent of Sulfur in Coal
2 r
Potential Sulfur Dioxide Emissions
Ubs/million Btu)
FIGURE 4-1. SO., Emissions Compared to dul Sulfur
-------
of 9 pounds per hour. Corresponding maximum annual emissions (based
on a 3,000 hour operating year) would be 13.5 ton per year or less than
5 percent of the annual value calculated using Figure 4-1.
The reason for the disparity between measured and estimated S0£
emission levels is unclear. It appears that $03 is somehow being removed
from the thermal dryer off-gas, possibly as a result of secondary wet scrubbing
In the case of fluid bed thermal dryers, a percentage of S02 may be
adsorbed by the coal due to the reaction of SO^ with flue gas oxygen and
water which forms sulfuric acid in the coal pores,22 Incomplete combustion
of coal in the dryer furnace may also account for the difference between
measured and estimated S0£ emission levels.
Of the coal cleaning (separation) processes, only pneumatic cleaning
operations contribute to air pollution. Emissions from pneumatic cleaning
consist of particulate matter only, because ambient air is used to separate
coal from refuse. The quantity and pressure of the air used depends on
the size of coal to be cleaned. For pneumatic cleaning of coal less than
0.375 inch, an average exhaust air volume is 14,200 cubic feet per ton of
feed coal. The exhaust air usually entrains 70 percent of the less than
43 mesh material in the feed coal. Typically, the less than 43 mesh
material accounts for about 20 percent of the total feed. Therefore, the
uncontrolled exhaust air could contain 280 pounds of dust per ton of
coal feed treated or 138 grains of dust per dry cubic foot. For-a
representative air table having a design capacity of 50 tons per hour,
uncontrolled particulate emissions could be as high as 14,000 pounds per
4-9
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hour. Annual uncontrolled particulate emissions (based on a 3,000 hour
operating year) would be 21,000 tons per year.
Crushing and sizing operations produce dry, small particles (0.5 to
6.0 microns) at ambient temperatures. The quantity of particulate matter
generated depends on the coal type, moisture level, and type of sizing
and screening operations.23
Particulate matter in the form of fugitive coal dust is emittad
from storage, transporation, and handling operations. The amount of
particulate matter generated varies widely, depending on such factors as
climate, topography, and coal characteristics including moisture content.
For example, the handling of thermally dried coal results in more particu-
late emissions than undried coal because the moisture content has been
lowered. It has been estimated that 80 pounds of coal per ton are lost
as fugitive particulate emissions during transporation and handling
operations. A particulate emission factor from coal storage piles has
been estimated at 0.0013 pounds per ton per year.-^
4.2.1 NSPS Control Techniques
Several types of air pollution control devices can be applied to
emissions from cleaning facilities. The choice of control device is
dependent upon the pollutant, the properties of the pollutant, and the
properties of the conveying medium. Particulate control devices are
broadly classified as dry inertia! collectors, filters, and wet scrubbers.
Dry inertia! collectors (cyclones) are characterized by moderate removal
efficiencies, low energy requirements, low capital and operating costs,
4-10
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and an ability to accommodate high inlet particulate loadings. They can
also operate at high temperatures. The major disadvantage of using cyclones
for emissions control is their low collection efficiency for particles
smaller than 10 microns. Consequently, they are generally considered part
of the operating process rather than part of the emissions control systein.
Fabric filters are regarded as one of the simplest and most reliable high
efficiency dry collection devices, capable of 99.9 percent removal of
submicron size particles. Fabric filters are suitable for a wide variety
of dry particulate removal applications. Limitations ara excessive
moisture, which tends to blind the fabric, and gas stream temperature,
which must be relatively cool. The advantages of wet scrubbers are high
removal efficiency,, ability to remove gaseous pollutants, tolerance of
moisture in the gas stream treated, and relatively low capital costs.
The major disadvantage of wet scrubbers is their high energy requirements.
4.2.1.1 Thermal drying. Exhaust air from thermal dryers is characterized
by high moisture content and low temperature (about 200°F). Particulate
levels are characteristically high due to the entrapment of fine coal
particles during the drying process.25 Fabric filters are not generally
applied on thermal dryers due to the high moisture content and low
temperature of the exhaust air. High moisture content combined with too
low an operating temperature results in the condensation of moisture that
produces blinding of the fabric (i.e., particulate matter is retained
within the fabric interstices or pores making resistance to gas flow
prohibitively high).
4-11
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The principle control device applied to thermal dryers is a wet
scrubber. Venturi type wet scrubbers associated with thermal dryers
normally operate at pressure differentials of 15 to 40 inches water
gauge. The equipment requires 3 to 10 gallons of water per 19000 cubic
feet per minute of gas cleaned. Water entrained by exhaust gases from
the scrubbers is removed using mist eliminators.
An average uncontrolled emission rate for fluid-bed dryers is
3.0 grains per dry standard cubic foot. Well-controlled thermal dryers
with high efficiency venturi type wet scrubbers reduce particulate
emissions to less than or equal to the standard of performance, which is
Q.031 grains per dry standard cubic foot. This is equivalent to 99
perce'nt control efficiency.
4.2.1.2 Pneumatic cleaning. Emissions from pneumatic coal cleaning
equipment consist entirely of particulate matter. Typically, emission
control is achieved by a fabric filter. In tests conducted by EPA,
particulate emissions measured from representative pneumatic cleaning
operations equipped with fabric filter control ranged from 0,004 to 3.011
grains per dry standard cubic foot. The existing standard of performance
for pneumatic coal cleaning equipment is 0.018 grains per dry standard
cubic foot.25
4.2.1.3 Storage, transporation and handling. Coal processing and conveying
equipment, storage systems, and transfer and loading facilities are subject
to the general opacity provisions of the NSPS. Fugitive emissions from
these sources may not exhibit 20 percent or greater opacity. Historically,
4-12
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these sources have been controlled by applying wet suppression techniques
and/or by completely enclosing the source. This is still generally true
for most plants processing Eastern (bituminous) coal. However, some of
the best controlled Eastern plants are now applying engineering controls
consisting of local hooding and ventilation systems for emissions capture
and control devices for collection. The EPA visited two such facilities.
One plant has two very similar production lines for processing bituminous
coal.27 The major difference in the two lines, from an emissions control
perspective, is that one uses low-energy scrubbers (Rotoclones) to control
fugitive sources and the other line uses fabric filters to control fugitive
sources. Sources which are hooded and ducted to the control devices
include conveyor transfer points upstream and downstream of the dryer and
the coal crusher. A fabric filter collects coal dust on one line upstream
of the dryer, evidence to the fact that fabric filters can tolerate some
ambient moisture without blinding. Emissions from the control devices
have never been measured; however, no visible emissions were detected in
the control device exhaust.~^
The other Eastern plant visited by EPA controls two dry-coal conveyor
transfer points by enclosure and venting to a fabric filter. The fabric
filter, which has a gas handling capacity of 3,000 ACFM, has never been
tested for emissions control performance.29
Some plants processing Western (lignite and subbituminous) coal
are also beginning to use engineering controls on sources of fugitive
emissions. Three such plants were visited by EPA as part of this review.
4-13
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One of the plants processes about 4,000 tons of lignite per hour.
This plant controls emissions from primary and secondary crushers using
pulse jet type fabric filters.30 Emissions from the fabric filters which
have gas handling capacities of 20,000 ACFM each were sampled by a contractor
for the company in 1979. Emissions from the primary crusher were found to
be 0.0014 gr/dscf, and emissions From the secondary crusher were 0.0025 gr/dscf.
Though EPA Method 5 was not used, the test method was evaluated by EPA and
judged to be comparable to Method 5 for the sampling conditions reported.
The lignite coal processed by the plant is inherently dry, and stack gas
moisture averaged only 1.1 percent during tests of both fabric filters.31
Even so, the fabric filters are insulated and heated to prevent condensation
of moisture. The fabric filters were installed in 1969.
A similar operation was visited by EPA and controlled fugitive emissions
from the processing of lignite coal by using four fabric filters.32 The fabric
filters ranged in gas handling capacity from 9,800 ACFM to 15,000 ACFM and
controlled emissions from vibrating feeders, crushers, storage silos and
conveyor transfer points. The fabric filters were installed between 1980
and 1933, and emissions from two of them were sampled in 1934. Emissions
ranged from 0.003 to 0.005 gr/dscf.
The third Western plant visited by EPA processes 460 tons per hour
of subbituminous coal and has a very extensive control system for sources
of fugitive emissions.33 Emissions captured from several sources are ducted
to a central fabric filter for particulate removal. The fugitive sources
treated by the central fabric filter include the primary crusher, the truck
4-14
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dump and the primary crusher feed and discharge locations. The fabric
filter treats 68,800 ACFM when the truck dump is operated and 28,800 ACFM
when the truck dump is not operated. Emissions from the fabric filter
were sampled in 1983, and averaged 0.005 gr/dscf.
After the coal at this plant has been processed it is transferred to
a 1250 ton per hour overland conveyor which carries the coal 5 miles to an
electric power generating plant. Three transfer points along the conveyor
are completely covered and vented to three separate fabric filters. One
of the fabric filters was tested in 1983, and was found to have particulate
emissions of 0.003 gr/dscf.
4.2.2 Controls Vihich Exceed NSPS
Several control techniques have been identified which have the
potential for exceeding the requirements of the MSPS for several of the
affected facilities:
0 Indirect thermal drying.
0 Venturi wet scrubber operation with greater pressure drops.
0 Lime scrubbing for S02 removal.
Enclosure followed by fabric filtration.
For indirect thermal drying, the coal being processed does not come
in contact with the hot furnace gases. Heat is transferred to the moist
coal through contact with previously heated elements, such as screws,
fins, paddles, steel balls, and chains. The principle advantage of
indirect thermal drying is its potential for reducing particulate emissions,
There are several disadvantages of indirect thermal drying, however,
4-15
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including high operating costs and limited capacity.34 No domestic,
commercial, indirect thermal dryers were found presently in operation,
thus operating characteristics could not be quantified.
Operating wet scrubbers at higher pressure drops could provide a
further reduction in particulate emissions from thermal dryers. The
highest pressure drop recorded on a scrubber demonstrated to be achieving
the NSPS for thermal dryers is 40 inches water gauge. Basing a revised
standard on the application of venturi scrubbers operated at substantially
higher pressure drops could result in a lower emission limit for the
standard. However, the resulting increase in energy consumption and
consequent impact on costs appear to be disproportionate to any benefits
derived. Energy requirements for venturi scrubbers are exponentially
related to the level of control achieved.
As mentioned in Section 4.2, gaseous emissions from thermal dryers
include sulfur dioxide ($02). These emissions are not regulated by the
NSPS. Removal of S02 can be accomplished by a process of wet absorption,
such as with a lime/limestone based scrubbing system. Removal efficiencies
range from 70 to 90 percent SO? in inlet gas.35 Although these operations
have achieved commercial status in flue gas desulfurization for util ity
and industrial boilers, installation and operating costs are high.35
Probably the most significant potential for additional control of
particul ate emissions from coal preparation plants is in,the area of
fugitive emissions from coal processing, conveying, transfer, loading,
and storage facilities. The current NSPS requires control of emissions
4-16
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from these operations only to the extent that they do not exceed 20 percent
opacity. As noted in Section 4.2.1.3, each of these sources is currently
being controlled at one or more plants by ventilation followed by fabric
filtration. Additional investigation is necessary to determine if more
stringent fugitive emission controls should be applied across the industry,
4.3 REFERENCES
1 Telecon. Georgieff, N.T., U.S. Environmental Protection Agency, with
Balthasar, M.C., U.S. Department of Energy. Energy Information
Administration. February 5, 1936. Number of coal preparation plants
built since 1980.
2. Letter and attachments from Overstreet, M.C., Virginia Air Pollution
Control Board, to Georgieff, M.T., U.S. EPA. January 13, 1986.
3 Telecon. Georgieff, N.T., U.S. EPA, with Johnson, Dick, Pennsylvania
Department of Environmental Resources. February 5, 1936. Number or
coal preparation plants built since 1930.
4. Letter from Helbling, G.O., North Dakota State Department of Health,
to Georgieff, N.T., U.S. EPA. February 11, 1986.
5 Letter from McCann, R.B., Kentucky Department of Environmental
Protection, to Georgieff, N.T., U.S. EPA. April 3, 1985.
6. TRW Energy Systems Group. A Review of Standards of Performance for
New Stationary Sources - Coal Preparation Plants. Prepared for U.S.
-nvironmental Protection Agency, Research Triangle Park, N.C.
Publication No. EPA-450/3-80-022. December 1980. 9Co.
7. Letter and attachments from Heath, C.C., U.S. Department of Energy -
Energy Information Administration, to Georgieff, N.T., U.S. EPA.
February 11, 1986. Annual listing of coal preparation plants
since 1930.
8. Mining Information Services of the McGraw-Hill Mining Publications.
1979 Keystone Coal Industry Manual. New York, N.Y. 1979. pp.729-739.
9. Reference 5.
4-17
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10.
U.S. Department of Energy. Energy Information Administration.
Annual Energy Outlook 1984, with Projections to 1995. Publication
Mo. DOE/EIA-0383(84). January 1985. p. xxvii.
11. Reference 10.
12. Reference 5.
13. Buroff, J., B. Hylton, S. Keith, J. Stauss, and L. McCandless.
Technology Assessment Report for Industrial Boiler Applications:
Coal Cleaning and Low Sulfur Coal . U.S. Environmental
Protection Agency. Research Triangle Park, N.C. Publication
No. EPA-600/7-79-178c. July 1979. p. 5-53.
14. McCandless, L.C., and R.8. Shaver. Assessment of Coal Cleaning
Technology: First Annual Report. U.S» Environmental Protection
Agency. Washington, O.C. Publication No. EPA-600/7-73-150.
July 1978. p. 154.
15. Telecon. Beck, L.L., U.S. Environmental Protection Agsncy, with
Balthasar, M.C., U.S. Department of Energy, Energy Information
Administration. November 5, 1985. Non-3ituminus Coal Production in
1985.
16. Reference 10.
17. Phillips, P.J. Coal Preparation and Combustion and Conversion.
Electric Power Research Institute. Palo Alto, California.
May 1978. p. 2-100.
18. U.S. Environmental Protection Agency. Compilation of Air Pollution
Emission Factors, Fourth Edition, Publication No. AP-42. Office of
Air Quality Planning and Standards, Research Triangle Park, N.C.
September 1985. p. 8.9-3.
19. U.S. Environmental Protection Agency. Background Information for
Standards of Performance: Coal Preparation Plants Volume I:
Proposed Standards. Research Triangle Park, N.C. Publication No.
EPA-450/2-74-021a.
20. Lemmon, A.W. Jr., G.I. Robinson, and O.A. Sharp. An Overview of
Control Technology. Proceedings: Symposium on Coal Cleaning to
Achieve Energy and Environmental Goals Volume II. (September 1978,
Hollywood, FL). U.S. Environmental Protection Agency. Research
Triangle Park, N.C. Publication Mo. EPA-600/7-79-098b. April 1979.
p. 794-823.
4-18
-------
21. Reference 19.
22. Reference 6. p. 4-13.
23. Lemmon, A.W. Jr., S.E. Rogers, G.L. Robinson, V.Q. Hale and
G E Raines. Environmental Assessment of Coal Cleaning Processes.
First Annual Report Volume II. U.S. Environmental Protect!on Agency
Research Triangle Park, M.C. Publication Mo. 600/7-79-073c. June 1979
p. 104-120.
24. Reference 20.
25 Nunenkamp, 0. Coal Preparation Environmental Engineering Manual.
U.S. Environmental Protection Agency, Research Triangle Park, N.C.
Publication No. EPA-600/2-76-138. May 1978. p. 547.
25. Reference 19.
27. Memorandum from Georgieff, M.T., U.S. EPA, to Crowder, J.U., £J>A.
December 18, 1985. Report on trip to Island Creek Coal Company,
Grundy, Virginia.
28. Reference 27.
29. Memorandum from Georgieff, M.T., U.S. EPA, to Crowder, J.U., EPA.
August 8, 1985. Report on trip to Clinchfiel d- Coal Company,
Moss III plant, Pitts ton County, Virginia.
30. Memorandum from Georgieff, N.T., U.S. EPA, to Crowder, J.U., EPA.
October 31, 1985. Report on trip to Falkirk Mining Company.
31. Memorandum and attachments from Bivins, D. C., EPA, to Georgieff,
M.T., EPA, October 30, 1985. Test report evaluation.
32. Memorandum from Georgieff, N.T., U.S. EPA, to Crowder, J.U., E3A.
October 17, 1985. Report on trip to Coteau Properties Company
Freedom Mine.
33. Letter and attachments from Mation, O.K. Montana Power Company,
Coal strip Project Division, to Fanner, J.R., U.S. EPA. December 24,
1985. Response to Section 114 letter on coal preparation plants.
34. Reference 23.
35. Reference 23.
36. Reference 6, p. 4-22.
4-19
-------
-------
5. ENFORCEMENT AMD COMPLIANCE
EPA Regional Offices, State agencies, and operating facilities
were contacted to obtain comments on enforcement aspects of the MSPS
and compliance testing results for new, modified, or reconstructed coal
preparation plants. Test data for thermal dryers, air tables, dust
suppression, wet dust collectors and fabric filters were also requested.
The information obtained supported information found in the literature
concerning process trends. Many coal preparation plants handling v:-ci"\-us
coal are removing the surface moisture of the coal by means of centrifuging.
This is one of the reasons for the small number of thermal dryers put
in operation since the standards of performance were reviewed in 1930.
Mo new air tables were installed during this period of time.
5.1 ENFORCEMENT APPLICABILITY
The MSPS for coal preparation plants clearly states that the
regulation applies to any plant which processes more than 200 tons per
day and includes any of the following operations: "Thermal dryers,
pneumatic coal-cleaning and conveying equipment {including breakers and
crushers), coal storage systems, and coal transfer and loading systems."
The scope of applicability, therefore, includes many facilities at stationary
sources not commonly referred to as "coal preparation plants." These include
large power plants, coke oven batteries, and large loading facilities.
5-1
-------
5.2 ANALYSIS OF NSPS TEST RESULTS
The results of compliance tests obtained from new, modified, or
reconstructed coal preparation plants with thermal dryers are summarized
in Table 5-1. All dryers were of the fluid bed design and emissions from
all were controlled using venturi scrubbers.
From the test data 1t can be seen that all plants are in compliance
with existing NSPS, with particulate emissions ranging from 0.005 to
0.024 grains per dry standard cubic foot. The pressure drops for the
venturi scrubbers listed in Table 5-1 range from 32 to 40 inches H20.
Generally, the units with the higher pressure drop producac lower
particulate emissions.
5.3 MONITORING AND RECQRDKEEPING
Review of the monitoring and recordkeeping provisions of the regulation
indicate that only one of the requirements may be questionable. This is
the requirement to continuously monitor the pressure of the water supply
to the scrubber. An increase in the water supply pressure could indicate
a beneficial situation (e.g., more water being supplied to the scrubber)
or a condition which would have a detrimental effect on scruober performance
(e.g., plugged spray nozzles). Also, the effect of some sets of conditions
may offset each other with a decrease in scrubber performance yet no net
change in water supply pressure. An example of offsetting conditions
would be a combination of broken spray nozzles and plugged spray nozzles.
5-2
-------
TABLE 5-1. COAL PREPARATION COMPLIANCE TEST RESULTS FOR THERMAL DRYERS
Plant Name
Consol
Pennsylvania
Coal Company
Consolld.
Coal Co.
Consolld.
Coal Co.
Consolld.
Coal Co.
Consolld.
Coal Co.
Plttston
Pittston
Plttston
Island
Creek
Coal Co.
Island
Creek
Coal Co.
Location
Bailey
preparation
plant
Enbn, PA
Nalller Mine
Mannlngton, UV
Blacksvllle
No. 2 dryer
Uana, UV
Amonate
plant
Amonate, UV
Buchanan
preparation
plant
Oak wood. VA
Moss III
Met Dryer
Dante, VA
Moss III
M1dds Dryer
McClure
River
VPS Mine
Oakwood, VA
VP6 Mine
Oakwood, VA
Date of Test
11/85
4/84
5/86
11/78
11/85
7-8/81
7-8/Bl
6/83
5/85
11/82
Participate
Emissions
gr/dscf
0.024
0.024
0.018
0.022
0.014
0.007
0.006
0.009
0.014
0.024
Process
Rate
ton/hr
688
678
810
380
413
400
300
1275
425
425
Venturl
Pressure Drop
In H20 Reference
32 to 35 1
30 to 32 1
28 to 30 1
32 1
34 to 37 1
35 2
35 2
39.5 3
35 4
35 5,6
-------
After concluding that water supply pressure is not a good indicator
of scrubber performance, we considered a revision to require the monitoring
of water flow to the scrubber. Such a requirement would eliminate the
concern about increased water supply pressure being the result of
plugged nozzles, but again, offsetting conditions such as a combination
of plugged and broken spray nozzles could result in no net change in
water flow.
As a result of discussions with EPA's Air and Energy Engineering
Research Laboratory (AEERL), this review determined that one good
indicator of water flow through the scrubber is the pressure drop
measured across the throat of the venturi.7 Since the NSPS currently
requires continuous monitoring of the pressure drop, this review concluded
that the requirement for continuous monitoring of water supply pressure
may be redundant.
This review also found that, unlike most other NSPS, the regulation
for coal preparation plants has no provisions for the reporting of
excess emissions. In searching for a meaningful indicator of excass
emissions, it was found that the pressure drop across the throat of the
venturi scrubber has a direct effect on scrubber performance. In fact,
a decrease of only 10 percent in the pressure drop across the scrubber
can result in a 75 percent increase in particulate emissions.8 Since
the NSPS requires continuous monitoring of the pressure drop across the
scrubber, a requirement to report pressure drop decreases in excess of
10 percent of the pressure drop measured during the performance test would
be a good indicator of possible excess emissions.
5-4
-------
5.4 REFERENCES
1 Letter and attachments from Brady, S.J., Consolidation Coal Company,
to Farmer, J.R., EPA. February 20, 1986.
2. Letter and attachments from Bryan, J., Pittston Coal Group, Inc.,
to Georgieff, N.T., U.S. Environmental Protection Agency. February 19,
1986.
3. Memorandum from Georgieff, N.T., U.S. Environmental Protection
Agency, to Crowder, J.U., EPA. September 9, 1985.
4. Kalb, G.W., Partial!ate Emission Test Fluidized Bed Thermal Coal
Dryer Virginia Pocahontas #5 Mine Island Creek Coal Company. TraOet
Laboratory. Wheeling, West Virginia. May 1985.
5. Letter and attachments from Overstreet, M.D., Commonwealth of
Virginia State Air Pollution Control Board, to Ramsey, G.D. , Garden
Creek Pocahontas Co. August 20, 1982.
6. TraDet Laboratories, Inc., Particulate Emissions Thermal Coal Dryer
Virginia Pocahontas #6 Mine Island Creek Coal Company. TraOet
Laboratories, Inc., Wheeling, West Virginia. November 1982.
7. Letter from Sparks, L.E., U.S. Environmental Protection Agency, to
Beck, L.L., EPA. February 9, 1987.
8. Reference 7.
5-5
-------
6. COST ANALYSIS
6.1 INTRODUCTION
The estimated and reported costs of particulate emission control
systems for new and modified coal preparation plants are presented in this
chapter. Eastern preparation plants, for the most part, utilize thermal
dryers and control them by venturi scrubbers. Venturi scrubbers are used
because the residual moisture remaining after thermal drying is sufficient
to cause fabric filters to blind, if the gas temperature should fall below
the moisture dew point. Western plants, which primarily process subbituminous
and lignite coals, generally from surface mines, rely on fabric filters.
The capital costs estimated by EPA are based on standard references or on
vendor quotes for major equipment, escalated to January 1986, via the
Fabricated Equipment component of the Chemical Engineering magazine "CE
plant cost index". The capital costs reported by industry were not listed
by individual pieces of equipment, but were reported for entire control
systems. T0 escalate the industry costs, the Mining and Milling industry
segment of the Marshall and Swift ("M&S") equipment cost index for the first
Quarter of 1986, also taken from Chemical Engineering, was used.
Investment and annualized costs of emission control for eastern plants
are presented in Section 6.2. The costs for controlling western plants and
fugitive sources are shown in Sections 6.3 and 6.4, respectively. Lastly,
cost-effectiveness data for these control measures are presented in Section 6.5,
6-1
-------
6.2 COSTS FOR CONTROLLING EASTERN PLANTS
6.2.1 Reported Costs
Four plants supplied cost information on their NSPS units.1 All uti-
lized venturi scrubbers following cyclones to control thermal dryers. In
the case of coal preparation plants, the manufacturing process requires
cyclones to maintain acceptable product yields. Thus, their costs should
not be charged against partlculate emissions control. A static pressure
drop of approximately 5 inches of water is required to operate the cyclones.2
The energy costs for operating the cyclones have been deducted from the
industry-reported annualized costs, to keep from distorting the control
costs per ton of coal processed and per ton of particulate captured (cost-
effectiveness). One other adjustment was made to the reported costs. Because
the industry figures did not allow for recovery of capital, a capital recovery
factor of 11.75 percent of investment was added to their annual costs. This
factor represents a 20-year equipment Hfe at a 10 percent annual interest
rate. (Note: this is a "real" Interest rate that does not consider either
income taxes or Inflation.) Table 6-1 gives the industry-reported investment
and annualized costs for the four eastern coal preparation plants.
6.2.2 Estimated Costs and Cost Comparison
The investment and annual 1 zed costs for three model plants were calcu-
lated by EPA for comparison with the industry data.3 The industry information
showed that the installation cost averaged 33 percent of the cost of the
control devices and auxiliaries.4 The EPA used the same factor. Table 6-2
presents the EPA costs. (The factors used to calculate the various annualized
costs are listed after each item in the table.)
6-2
-------
TABLE 6-1
CONTROL COSTS FOR EXISTING EASTERN
COAL PREPARATION PLANTS*.**
Air Volume, acfm
lit:-,,,
Installation
Loveridge
245,000
139,100
' s/yr
Oerhead 16,900
Taxes I Insurance lIoOO
Caoital Recovery (10%, 20 yr) 68,800
Tot aid {
Blacfcsville »2
145,000
134,100
11,500
1.000
52,100
Bailey Buchanan
145,000 175,000
$133,700
188,900
9,000
107,700
$439, 30U
$444,000
$109,000
205,400
9,500
112,300
$436, 2QU
$450,000
$160,800
209,900
9,500
148,200
ssw'.ooo
11,500
1.000
52,900
11,500
1.000
62,700
$204,000
Deference 5.
bThese costs pertain to venturi scrubbers installed to control partial! ate
emissions from existing thermal dryers. The costs of product recovery equipment
(e.g., cyclones) are not included in the above numbers.
^Industry total was escalated to first quarter 1986 dollars via the
Marshall and Swift (M&S) cost index.
costs have been rounded to three places.
6-3
-------
TABLE 6-2
CONTROL COSTS FOR MODEL EASTERN
COAL PREPARATION PLANTSa>b
Air Volume, acfm 90,000 160,000 240,000
Investment, $
Cyclone/Scrubber $120,000 $185,000 $260,000
Fan 4 Motor 131,700 168,100 181,500
Circulating Pump & Motor 3,200 7,000 7,900
Make-up Pump & Motor 1,900 2,200 2,700
Thickener Pump & 'tfotor 2,200 2,500 2,700
Transfer Point Baghouse 24,500 27,200
Fan & Motor " _ 1,600 2,100
Total Major Equipment $259,000 $390,900 $434,100
Insallation 86,300 130,300 161,400
Total0 $345,000 $521,000 $646,000
Annualized Costs, $/yr
Labor (1.5 mhr/shift
9 $14.37/hr) $ 12,900 $ 12,900 $ 12,900
Utilities, 9 $0.04/kwh 146,800 261,000 391,400
Overhead, 9 80% of Labor 10,300 10,300 10,300
Taxes I Insurance,
3 4% of Investment 13,400 20,800 25,300
Capital Recovery (10%,
20yr) 39,400 61,200 75,800
Total0 $223,000 $366,000 $516,000
References 6-10.
bThese costs pertain to venturi scrubbers for control of thermal dryers
in the model pi ants.
cTotal costs have been rounded to three places.
6-4
-------
Figure 6-1 compares the industry-reported and the EPA-estimated
investment costs. A reasonably good agreement is evident. Figure 6-2
compares the reported and estimated annualized costs. The EPA annualized
costs are somewhat higher than the industry-reported costs. One of the
largest components of the annualized costs is the cost of power, which
varies in proportion to the capacity utilization (operating hours). The
EPA estimates assume full capacity utilization during the reported hours of
operation. It is evident from the reported costs that the industry capacity
utilization is well below the maximum. If the industry costs were adjusted
to reflect full capacity utilization, the differences between them and the
EPA estimates would likely be smaller than those shown in Figure 6.2.
6.3 COSTS FOR CONTROLLING WESTERN PLANTS
6.3.1 Reported Costs
The reports from western plants did not furnish detailed costs for
individual pieces of equipment, only costs for total investment and annual
maintenance. Therefore, no itemized industry costs can be shown.
6.3.2 Estimated Costs and Cost Comparison
EPA estimated costs for fabric filters to control emissions from a
western coal preparation plant (Freedom, NO). These costs are based upon
the engineering parameters reported by industry sources. Table 6-3 shows
both the capital cost totals reported by industry and the costs estimated
by EPA. Generally, the reported and estimated costs differ by less than +_
30 percent. The control devices to control Sources 13 and 19 are identical,
yet the cost for Source 19 exceeds Source 18 cost by fifty percent. Presumably,
additional equipment was charged to the Source 19 project, so that the
lower cost for Source 18 is probably the correct one for both sources.
6-5
-------
Investment Cost.
700 r
600
500
400
300
200
100
0
FIGURE 6-1
EASTERN COAL PREPARATION PLANTS
Investment Cost vs Air Volume
x 1000
^^--•''"""^
Estimated
—e—
Reported
0
20 40 60
—i 1 j 1 i • i i i i
80 100 120 140 160 100 200 220 240 260
Air Volume, acfm x 1000
-------
FIGURE 6-2
EASTERN COAL PREPARATION PLANTS
Annualized Cost vs Air Volume
Annualized Cost. $ x 1000
600 r
500
400
300
200
100
0
Estimated
unspecified
Reported
A
A
A
A
A
0 20 40 60
80 100 120 140 160 180
Air Volume, acfm x 1000
200 220 240 260
-------
TABLE 6-3
CONTROL COSTS FOR SOURCES AT A
WESTERN COAL PREPARATION PLANT
(FREEDOM MINE, N0)a>°
Emission Source Number 17 18 19 20
Air Volume, acfm . ' 10,100 15,000 15,000 9,300
Baghouse Cloth Area, sq. ft. 1,155 1,732 1,732 1,367
Pressure Drop, in. of V^O 6 666
Installed Capital (Reported): $64,875 $70,439 $106,707 NR
Date of Installation 12-83 12-83 8-84 7-33
Installed Capital (Escalated
to 1st Qtr. 1986)d: $65,400 $71,000 $106,000
Investment Cost (Estimated)
Baghouse $10,700 $13,400 $13,400 511,700
Insulation add on 10,300 11,500 11,500 10,700
Bags 700 1,000 1,000 900
Motor 800 1,300 1,300 800
Fan 1,100 1V400 l,.40g 1,100
Major Equipment Total MET $23,600 $23,600 $28,600 $25,200
Installation, 9 72% of MET 17,000 20,600 20,600 18,100
Indirect Cost, 9 45% of MET 10,600 12,900 12,900 11,300
Totald J51.200 $62,100 $62,100 $54,600
Annualized Cost
Labor $3,520 $5,120 $5,990 $2,060
Materials 430 1,960 1,010 1,560
Utilities 2,230 3,380 3,330 2,210
Overhead, 9 80% of Labor 2,820 4,100 4,790 1,640
Taxes and Insurance, 9 4% of 2,050 2,480 2,480 2,190
Investment
Capital Recovery (10%, 20 yrs) 6,020 7,280 7.280 6,440
Totald $17,100 $24,300 $24,900 $16,100
Deferences 11-15.
^Costs are for a fabric filter (baghouse) to control each of Che above sources
clndicates that no cost was reported for this source.
dTotal costs have been rounded to three places.
6-8
-------
6.4 COSTS FOR CONTROLLING FUGITIVE EMISSION SOURCES
There are several sources o* fugitive emissions in a coal preparation
plant, such as truck dumps, conveyor transfer points, and crusher discharges.
For the control of these fugitive emissions, three sizes of control systems
have been costed: a 1,000-, a 5,000- and a 10,000-acfm unit, which can
handle the gas volumes captured by a 5-, a 25-, and a 50-square foot
hood, respectively. Costs for both venturi scrubber and fabric filter
systems have been estimated by EPA for each of these three flowrates.
Table 6-4 sets forth the investment costs for the three venturi scrubber
systems; Table 5-5 details their annualized costs. Investment and annualizsd
costs for the three Fabric filter systems are shown in TaDles 5-6 and 5-7,
respectively.
5.5 COST-EFFECTIVENESS OF THE PRESENT NSPS CONTROLS
The cost-effectiveness of controlling particulate emissions at existing
coal preparation plants to meet the present NSPS has also been calculated,
based on data supplied by coal preparation plants.
Table 6-3 shows the cost effectiveness calculations for coal dryers
operated by the Consolidation Coal Company mines in the eastern U.S. The
cost of pollution control ranges from SO.06 to SO.10 per ton of coal cleaned,
and the cost-effectiveness ranges from $10 to S15 per ton of particulate
captured.
Table 6-9 shows the cost-effectiveness calculations for four sources
of fugitive emissions at the Freedom Mine of North American Coal Corporation
(NACC) in Beulah County, North Dakota. Based on information submitted by NACC,
the control cost per ton of coal approximates $0.01, and the cost-effectiveness
is 33.18 per ton of particulate matter collected.
6-9
-------
TABLE 6-4
VENTURI SCRUBBER INVESTMENT COSTS FOR
FUGITIVE EMISSIONS CONTROL
Air Volume, acfm
Venturi Scrubber*
Fan (15" Static Pressure)15
Motor-c and Starter
Water Pumpd and Motor
Ductwork & Hoods
Major Equipment Total (MET)
Sales Tax, Freight,
Instrumentation, @ 13% of MET
Installation Direct Costs,
9 56% of METe
Installation Indirect Costs,
9 35% of
Total Investment Costf
1,000
$4,050
675
1,351
1,741
2,323
$7,822
1,430
5,209
3,256
$17,800
5,000
$6,250
1,640
2,101
1,741
3,518
$15,250
2,745
10,077
6,298
$34,400
10,000
$8,270
1,640
4,923
1,741
5,442
322,016
3,302
14,178
3,861
$48,400
Reference 16.
^Reference 17.
cRefarance 13.
dRefarence 19.
Deference 20.
fTotal costs have been rounded to three places.
6-10
-------
TABLE 6-5
VENTURI SCRUBBER ANNUALIZED COSTS FOR
FUGITIVE EMISSIONS CONTROL
Air Volume, acfm
Labor, 2hr/shift 9 $12/nra
Supervision, 9 15% of Labor
Overhead, 9 80% of Lab. + Supv.
Utilities
Taxes, Insurance, & GiA, 9 4% of
Investment
Capital Recovery (10 years, 10%)
Maintenance, 9 5% of Investment
Total Annualized Costb
Particulate Captured, tons/yr.c
Cost Effectiveness, S/ton
JJ300
$13,200
1,980
12,144
1,600
710
2,891
888
$33,400
67.9
492
5,000
$13,200
1,980
12,144
8,000
1,374
5,592
1,719
$44,000
338
130
10,000
$13,200
1,980
12,144
16,000
1,934
7,363
2,417
$55,600
676
82
Reference 21.
bTotal costs nave been rounded to three places.
cinlet particulate loading of 4 gr./dscf, 90% removal efficiency,
4,400-hr/yr operating factor.
6-11
-------
TABLE 6-6
FABRIC FILTER INVESTMENT COSTS FOR
FUGITIVE EMISSIONS CONTROL
Air Volume, acfm
Fabric Filter Cost w/o Bags3
Polypropylene bags*3
Fanc Motor** and Starter
Ducting 4 Hood
Major Equipment Total (MET)
Sales Tax, Freight,
Instrumentation, @ 18% of MET
Installation Direct Costs,
£ 72% of METe
Installation Indirect Costs,
§ 45% of
Total Investment Costf
1,000
$10,000
488
2,286
1,751
$14,525
2,615
10,458
6,536
$31,500
5,000
$28,667
2,440
2,400
2,400
$35,392
6,370
25,482
15,926
$76,800
10,000
$52,000
4,880
6,000
6,000
$71,535
12,876
60,776
37,985
$183,000
Reference 12.
Reference 13.
Reference 17.
^Reference 18.
SReference 21.
costs have been rounded to three places.
6-12
-------
TABLE 6-7
FABRIC FILTER ANNUALIZED COSTS FOR
FUGITIVE EMISSIONS CONTROL
Air Volume, acfm
Labor, 2hr/shift 9 $12/hra
Supervision, 9 15% of Labor
Overhead, 9 80% of Lab. + Supv.
Utilities
Bag replacement (2-year life)
Taxes, Insurance, & GSA, 9 4% of
Investment
Capital Recovery (10 years 10%)
Maintenance
Total Annualized Cost3
Participate Captured, tons/yr.b
Cost Effectiveness, $/ton
1,000
$13,200
1,980
12,144
392
244
1,261
5,128
1,576
5,000
$13,200
1S980
12,144
1,960
1,220
3,072
12,495
3,840
10,000
$13,200
1,980
12,144
3,921
2,440
7,327
29,802
9,159
$35,900
74.7
481
$49,900
372
134
$30,000
743
108
aTotal costs have been rounded to three places.
blnlet particulate loading of 4 gr./dscf, 99% removal efficiency,
4,400-hr/yr operating factor.
6-13
-------
TABLE 6-3
COST EFFECTIVENESS CALCULATIONS FOR PARTICULATE CONTROL FROM
DRYERS AT EXISTING EASTERN COAL PREPARATION PLANTS
Loveridge Blacksville#2 Sailey Buchanan
WV WV PA VA
Coal Cleaned, tons/hr , 935 310 688 413
Operating Time, hrs/yr 3,625 6,000 4,500 4,830
Production, 103 tons/yr 3,389 4,860 3,096 1,995
Annual Uad Control Cost, $103/yra 272 302 177 204
Control Cost, S/ton of coal 0.080 0.062 0.057 0.102
cleaned
Average 1984 Coal Price, $/tonb 36.74 36.74 34.56 37.10
Control Cost as Percent 0.22 0.17 0.16 0.27
of Coal Price
Particulate Captured, tons/yr 21,300 20,900 15,700 20,300
Cost-Effectiveness, $12.80 $14.40 $11.30 $10.00
S/ton of Particulate
Table 6-1.
^Reference 22.
6-14
-------
TABLE 6-9
COST EFFECTIVENESS CALCULATIONS FOR
EXISTING WESTERN COAL PREPARATION
(BEULAH COUNTY, ND)
Capacity, tons/yr 8,320,000
Annualized Cost, $/yr 32,445
Control Cost, S/ton of capacity 0.0099
Control Cost as percent of coal price (S9.69/ton) 0.10
Total particulate matter captured, tons/yr 10,079
Cost effectiveness, S/ton of particulate 8.18
6-15
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6.6 REFERENCES
1. Letter from Brady, Spencar J., Consolidation Coal Co., to Carrier, J.R.,
EPA. February 20, 1986. (§114 response.)
2. Letter from Werle, Don, Flex-Kleen Corporation, to Georgieff Maum T.,
EPA. November 12, 1985. (Scrubber costs.)
3. Memo from Georgieff, Naum T., EPA, to Jenkins, R.E., EPA. March 21; 1986.
(Model plant parameters.)
4. Reference 1.
5. Reference 1.
6. Reference 3.
7. Telcon. Jenkins, R.E., EPA, to Rich Bohinc, Westinghouse Corporation.
April 4, 1986. (Electric motor costs.)
3. Letter from Almon, Duke, PNUCOR, to Jenkins, R.E., EPA. April 8, 1986.
(Pump quote.)
9. Quote from Robinson Industries to Georgieff, Maum T., EPA. January 15, 1986.
(Fan quote.)
10. Reference 1.
11. Letter from Stromberg, Andrea L., The Morth American Coal Corporation,
to Farmer, J.R., EPA, March 18, 1986. (§114 response.)
12. i'lemo from Buck,
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18. Reference 15, §100-550, p.6.
19. Reference 15, §100-232, p.4.
70 Neveril, R.B., Capital and Operating Costs of Selected Air Pollution Control
" Systems, U.S. Environmental Protection Agency, tPA 45U/b-au-uu
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7. CONCLUSIONS
The current NSPS for coal preparation plants has remained unchanged
since it was proposed in 1974 and reviewed in 1979. The primary purpose
of the NSPS was to control particulate emissions from thermal coal dryers.
These emissions, from an estimated 200 coal dryers operating with existing
controls in 1968, exceeded 150,000 tons nationwide.
The production of coal in the United States has been growing at an
average annual rate of about 3 percent since promulgation of the NSPS.
However, the U.S. Department of Energy forecasts that growth will decline
to an average annual rate of 2.3 percent between 1985 and 1995. Furthermore,
the average annual rate of growth in production of Western coal (mostly
lignite and subbituminous) is-projected to exceed the annual growth rate in
Eastern coal production over the next 10 years (3.6 percent versus 1.6 percent)
Western coals are predominantly removed by surface (strip) mining techniques
in relatively arid portions of the country, whereas Eastern coals are
predominantly removed via underground (shaft) mines and the coal is wet
because of water sprayed on the coal during the mining process. Consequently,
the handling of Western coal, where more of the growth is expected to
occur, is more conducive to generating fugitive particulate emissions than
handling undried Eastern coal. The economics of coal preparation technology
is resulting in declining use of thermal drying in favor of mechanical
dewatering for Eastern coals. Western coals are not dried either thermally
or mechanically.
7-1
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7.1 COAL DRYERS AND PNEUMATIC CLEANING FACILITIES
Of the 84 coal preparation plants per year expected to be built during
the next decade, probably fewer than two per year will use thermal dryers.
This is primarily the result of the industry's selection of mechanical
dewatering technology. Mechanical dewatering, which is not a significant
source of air emissions, offers the advantage of being less energy intensive,
and- consequently less costly, than thermal drying. The use of thermal
drying of coal is expected to continue to decline. The use of pneumatic
coal cleaning equipment has also been declining and no new pneumatic coal
cleaning facilities are projected.
With the exception of a total ban on the use of thermal drying, no nsw
technology was found to be capable of reducing emissions significantly below
what is currently required by the NSPS.
7.2 COAL TRANSFER, HANDLING, AND STORAGE SYSTEMS
Technology is available to control the transfer, handling, and storage
of both Eastern and Western coals more effectively than the requirements of
the current NSPS. As indicated in Section 4.2.1,3, particulate grain
loadings range from 0.001 gr/ dscf to 0.005 gr/dscf. While no EPA Metnod 9
opacity data are available for these facilities, unofficial observations by
State and EPA personnel indicate that the opacities at the processes being
controlled and at the exhausts of the control devices are generally zero.
A wide range of coal types and processing tnethods used by the
approximately 1400 coal preparation plants operating in the United States.
Controls which are appropriate and cost-effective at one plant, however,
7-2
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may be inappropriate for another. For example, coal crusher and conveyor
transfer points are being controlled by fabric filtration at some Western
plants with an estimated cost effectiveness of less than $500/ton of parti -
culate captured. However, Eastern coal at some processing locations is so
wet as it comes from the mine that uncontrolled processing operations
upstream of the dryer present no significant potential for particulate
emissions. Those Eastern plants which process dryer, dustier coals frequently
control sources of fugitive particulate emissions by using water sprays.
Spraying water on some of the Western coals would be totally inappropriate
since it would add unwanted moisture and create a freezing problem at some
plants located in severe winter climates.
The coal preparation industry has been growing since proposal of the
NSPS, and all new or modified coal preparation plants have potential sources
of fugitive emissions which are subject to the existing 20 percent limit on
opacity. Also, this review found that many of the newer plants are con-
trolling sources of fugitive emissions to a degree beyond that which is
required by the existing NSPS.
7.3 MONITORING AND RECOROKEEPING
During our review of the monitoring and recordkeeping provisions of
the regulation, only one requirement was found to be questionable. This is
the requirement to continuously monitor the pressure of the water supply to
the scrubber.
7-3
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TECHNICAL REPORT DATA
(Please read Instructions on the reverse before completing;
1. R6PORTNO.
EPA-450/3-88-001
3. RECIPIENTS ACCESSION NO.
4. TITLE ANO SUBTITLE
Second Review of New Source Performance Standards
for Coal Preparation Plants
5. REPORT DATE
February 1988
6. PERFORMING ORGANIZATION COOE
7. AUTHOH(S)
8. PERFORMING ORGANIZATION REPORT NO.
9. PERFORMING ORGANIZATION NAME ANO ADDRESS
Office of Air Quality Planning and Standards
U.S. EPA, Research Triangle Park, NC 27711
10. PROGRAM ELEMENT NO.
11. CONTRACT/GHANT NO.
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TECHNICAL REPORT DATA
/Ptease read Instructions on the reverse before completing}
1. REPORT NO.
EPA-450/3-88-001
3. RECIPIENT'S ACCESSION NO.
4. TITLE AND SUBTITLE
Second Review of New Source Performance Standards
for Coal Preparation Plants
3. REPORT DATE
February 1988
8. PERFORMING ORGANIZATION COO6
7. AUTHOR(S)
I. PERFORMING ORGANIZATION REPORT NO.
a. PERFORMING ORGANIZATION NAME AND ADDRESS
Office of Air Quality Planning and Standards
U.S. EPA, Research Triangle Park, NC 27711
10. PROGRAM ELEMENT NO.
11. CONTRACT/CHANT NO.
12. SPONSORING AGENCY NAME AND ADDRESS
13. TYPE OF REPORT AND PERIOD COVERED
Final
1*. SPONSORING AGENCY COO6
EPA/200/04
1 IS. SUPPLEMENTARY NOTES
16. ABSTRACT
The new source performance standards (NSPS) for coal preparation plants
(Subpart Y of 40 CFR Part 60) were reviewed by the U. S. Environmental
Protection Agency for the second time. The industry and other government -
agencies were contacted to obtain data. The review found that the use of
coal dryers and pneumatic coal cleaning equipment is declining, and that no
new technology exists for these facilities. Technology exists for more
stringent control than required by the NSPS for sources of fugitive emissions
from coal transfer, handling, and storage facilities because of recent
application of high efficiency control equipment for particulate emissions.
17.
KEY WORDS AND DOCUMENT ANALYSIS
DESCRIPTORS
b.IDENTIFIERS/OPEN ENDED TERMS C. COSAT1 Fieid/Grouo
Air Pollution
Pollution Control
Standards of Performance
Coal Cleaning
Particulates
Air Pollution Control
Stationary Sources
13B
18. DISTRIBUTION STATEMENT
Unlimited
19. SECURITY CLASS {This Report)
TTnrl agq-f f-i oH
120. SECURITY CLASS (Tins page!
Unclassified
21. NO. OP 3AGcS
73
22. PRICS
SPA Form 2220-]
». 4-771
previous eoirioN n
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