AP42 Section: 11.10 Coal Cleaning
Title: Comments
1994
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MIDWEST RESEARCH INSTITUTE
Suite 350
401 Harrison Oaks Boulevard
Gary. North Carolina 27513-2412
October 17, 1994 Telephone (919) 677-0249
FAX (919) 677-0065
John Wootten
Vice President, Engineering and Environmental Affairs
Peabody Holding Company, Inc.
701 Market Street
Suite 700
St. Louis, Missouri 63101-1826
Dear Mr. Wootten:
As discussed with Jim Lunan of Peabody Holding Company, Inc. (Peabody) this
morning by telephone, Midwest Research Institute currently is assisting the U. S.
Environmental Protection Agency (EPA) in revising Section 8.9, Coal Cleaning, of the
publication Compilation of Air Pollutant Emission Factors, otherwise known as AP-42. A
draft revision to this AP-42 section was sent to the National Coal Association (NCA) on
January 12, 1993 for review. Based on NCA*s response, EPA is now trying to gather
additional test data that is more representative of current operations in the coal cleaning
industry to incorporate into the revised AP-42 section. Enclosed is a copy of the draft AP-42
section on coal cleaning and a copy of the February 16, 1993, letter from David Branand of
the NCA to Ron Myers of EPA with NCA's comments on the draft AP-42 section.
During a recent conversation with NCA, Mr. Branand suggested that we contact you
for additional information. Therefore, we are requesting-your help in obtaining emission test
reports on coal cleaning sources. Please note that the emission factors presented in AP-42
generally are based upon the results from validated tests or other emission evaluations that
are similar to EPA test methods. We also would appreciate any comments that you could
provide on the process description and identification of emission points presented in the
enclosed draft AP-42 section. Please note that we need to receive any additional information
no later than December 31, 1994 in order to incorporate it into the revised AP-42 section on
coal cleaning.
Thanks for you help.
Sincerely,
lard J, Marinshaw
Senior Environmental Engineer
2 Enclosures
cc: James S. Lunan, Peabody
Ron Myers, EPA (MD-14)
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MIDWEST RESEARCH INSTITUTE
Suite 350
401 Harrison Oaks Boulevard
Gary, North Carolina 27513-2412
Telephone (919) 677-0249
FAX (919)677-0065
September 28, 1994
Richard Kerch
Director, Air and Water Quality Assistance
CONSOL, Inc. ••
1800 Washington Road
Pittsburgh, Pennsylvania 15241
Dear Mr. Kerch:
As we discussed this morning by telephone, I am forwarding
to you a copy of the draft revised AP-42 section on coal cleaning
and a copy of the February 16, 1993, letter from David Branand of
the National Coal Association, to Ron Myers, U. S. Environmental
Protection Agency, commenting on the draft AP-42 section. We
would appreciate your help in obtaining emission test reports on
coal cleaning sources. In addition, any comments that you could
provide on the process description and identification of emission
points as presented in'the draft AP-42 section would be helpful.
Please note that we will need to receive any additional
information no later than December 31, 1994 in order to
incorporate it into the final AP-42 section.
Thanks for you help.
Sincerely,
J. Marinshaw
Senior Environmental Engineer
2 Enclosures
cc: Ron Myers, EPA (MD-14)
3376
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NATIONAL
COAL
ASSOCIATION
February 16, 1993
Mr, Ronald E. Myers
United States Environmental Protection Agency
Emissions and Methodologies Section
Emission Inventory Branch
Office of Air Quality Planning and Standards
Research Triangle Park, NC 27711
Dear Mr. Myers:
By letter of January 12, you provided the National Coal Association (NCA) with an
opportunity to comment on draft AP-42 Section 8.9, Coal Cleaning revisions. NCA, whose
membership produces almost two-thirds of the nation's annual one billion tons of coal
production, is pleased to submit these comments. Although you requested comments by
February 15 (Washington-Lincoln Day and a federal holiday), NCA was unable to comply
with this deadline and trusts that the attached comments submitted on February 16 will be
accepted. The NCA comments are based on responses from the NCA Environmental
Committee which reviewed copies of your January 12 letter with enclosures.
It is apparent from the comments that NCA could work with its members to provide
EPA with additional data. The short comment period has prevented inclusion of this
information with these comments. However, NCA would welcome the opportunity to work
with EPA.
x-Rfspectfully
David C. Branand
Counsel and Director, Environmental
Affairs
1130 Seventeenth Street, N.W.
Washington, D.C. 20036-4077
(202) 463-2625
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NATIONAL COAL ASSOCIATION COMMENTS ON CHAPTER 8 OF
A4-42 SECTION 8.9
COAL CLEANING REVISIONS 11/92
February 16, 1993
INTRODUCTION
The U.S. EPA is in the process of updating the document Compilation of Air Pollutant
Emission Factors, Volume I: Stationary Point and Area Sources (commonly referred to as
AP-42). Chapter 8 of this manual addresses the mineral industry with a sub-section dealing
with coal cleaning plants. Within this section, thermal dryers are identified as the primary
source of emissions. EPA has asked for comments regarding a proposed draft of the revised
section on coal cleaning plants specific to thermal dryers. The National Coal Association
(NCA) comments regarding this draft are documented in this correspondence.
COMMENTS & DISCUSSION
Low Quality Data: All of the emission factors presented in this document have either a
"below average (D)" or "Poor (E)" quality rating. Using the EPA definition, these factors
may not be representative of the industry and have limitations on their use. Considering
the quality of the emission factors, this current draft is of little value in estimating emission
levels.
Old Data: Most of the emission factors are based on sampling data collected in the early
1970s. These data were obtained by first-generation stack samplers using first-generation
equipment. Much of this work was complicated by the unusual problems associated with
coal dryers such as saturated gas streams and cyclonic flows. Since then, improvements have
been made in all facets of stack sampling.
The current draft document states that the past sampling efforts have shown no CO
emissions as measured by ORSAT analysis (EPA Method 3). This method has a detection
limit of ~0.1% or -1000 ppm. The use of more sophisticated analytical instrumentation
such as electrochemical sensors and gas chromatography has shown measurable amounts of
CO in thermal dryers. It is a misconception based upon the earlier data that thermal dryers
do not emit CO. This misconception could prove to be a future permitting obstacle.
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Other advancements in Q A/QC procedures have led to improved data. Improvements have
also been made on the thermal dryers themselves including the use of "high energy" venturi
scrubbers. These collectors operate at pressure drops greater than 36 WG and afford
greater paniculate collection compared to their "low energy" counterparts. High energy
scrubbers have also shown to be effective in removing SO2 and to a lesser degree NOX.
Emission factors should be based on this type of collection device.
Units for Emission Factors: The expression of emission factors in "mass of emission per
mass of coal throughput" is only valid for the particulate emissions and possibly the VOCs.
The particulate emissions are primarily a product of entrained coal fines and may correlate
to coal throughput. The primary VOC emissions are dependent on the coal type and
combustion process. However, secondary VOC emissions can be generated during the
drying process. In some cases, the secondary VOC emissions are greater than the primary
VOC emissions. All other emissions are the products of combustion and should be
expressed in either "mass of emissions per mass of fuel fired" or better as "mass of emissions
per MM Btu of fuel fired."
Type of Combustion and Conditions: Consideration should be given to the type of
combustion and also the furnace conditions. The coal industry operates both stoker-fired
and pulverized coal-fired systems. The differences in these combustion processes can affect
the NO,, CO, and VOC emissions.
Coal Characteristics: The type and quality of the fired coal has a direct effect on the
emissions of SO2, NOX, VOCs, and CO, The SO2 emissions are a function of the amount
of coal fired, its sulfur content, and the SO2 removal across the venturi scrubber. The
removal across the scrubber can vary considerably depending on the local scrubber water
quality.
Other coal quality parameters such as volatile matter, fixed carbon, and grind size can affect
the NO^ VOC, and CO emissions. A recent study conducted by an NCA member showed
that the majority of the particulate emitted from thermal dryers consists of fine coal
particles. Emission of inorganic species would be predominantly dependent on the
concentration of these species in the original coal matrix. Also, the coal size and friability
could affect the amount of fine coal entrained in the flue gas during the drying step. These
parameters vary depending on the coal.
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COMPARISON WITH COLLECTED DATA
The data in the following table compares the current AP-42 estimates with measured
emissions for two post-1966 construction thermal dryers.
Species
Filterable
Paniculate Matter
CO
C02
S02
NOX
VOCs
AP-42 Estimate
(Ib/hr)
8.5
Not Detected •
Not Measured
110
11
3.5
Dryer # 1 PC Unit
(Ib/hr)
10.8
32
14100
157
36
-50
Dryer # 2 Stoker
Unit (Ib/hr)
26.5
...
22000
27.3
52
3.5
The variability in the data shown in this table illustrates the gross miscalculations that can
result when using the current AP-42 emission factors. The AP-42 estimates carry an order
of magnitude uncertainty for all the above species. The data clearly show the limited value
of the current emission factors.
RECOMMENDATIONS
Thermal dryer emissions are dependent on a wide variety of variables. The differences in
dryer designs also affect the emission rates. The source specific nature of thermal dryer
designs and operation results in a wide degree of variability in their emission rates. Because
of this, the current AP-42 factors are of limited value in the estimation of thermal dryer
emissions from a specific facility. A more accurate estimate would be to use the measured
emission rates from a facility that most closely resembles the dryer in question and to use
an appropriate scaling factor to project the emissions. Two potential scaling factors are the
tons of water evaporated and the gas flowrate. This technique eliminates the potential
biases previously discussed such as firing type, fuel type and quality, control equipment, etc.
The emission factors should be expressed on "mass of emissions per MM Btu of fuel fired"
basis for all emissions except particulate matter and VOCs. These emissions are greatly
influenced by the type and quantity of coal throughput and are better expressed on the basis
of "mass of emissions per ton of coal throughput."
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The database regarding CO emissions is invalid. It is a misconception to assume that
thermal dryers which use coal as a heat source have no CO emissions. Consideration should
be given to what these levels are for the different firing configurations,
Since 1979, the coal industry has conducted many thermal dryer source tests. Most of these
tests involved the measurement of particulate matter, NO^, and SO2. In some of these tests,
VOC and CO measurements were also taken. These data could be useful to the EPA in
their determination of the variability in thermal dryer emissions. This would also give EPA
some additional insight into the utility of emission factors,
There are some limitations to the current industry data. The objective of most of these tests
was to measure emission rates during "routine and normal" dryer operation. For the
majority of these tests, no data regarding the fuel firing rate of the dryer throughput were
required or taken. For these reasons it would be prudent for EPA to undertake a program
to compile and review the most current data and to re-assess their emission factors based
on their findings.
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FAX TRANSMISSION
TO: Ron Myers, EFIG
FROM: Rick Marinshaw, MRI
DATE: February 14, 1995
RECEIVING FAX NUMBER: 541-0684
SENDING FAX NUMBER: 919-677-0065
THIS FAX CONSISTS QfPAGES (INCLUDING THIS PAGE)
As I mentioned during our phone conversation yesterday, I am sending you a
fax copy of the results of an emission test conducted on a coal preparation plant
thermal dryer provided by Dick Kerch of CONSOL, The table includes run by run
emission rates and emission factors for several pollutants. Mr. Kerch said that
CONSOL has conducted emission tests on eight thermal dryers over the past year
and that they can provide at least the summaries of those tests. He can send
similar summaries for all the tests right away, but it may take time for them to
provide us with complete copies of the test reports.
The emission factors in the accompanying summary table are in units of
mass (IbJ emitted per heat input (millions of BTUs). In the current AP-42 section,
the emission factors for coal cleaning are presented in units of mass emitted per
mass of coal dried. According to in-house studies performed by CONSOL,
emissions are more a function of heat input than tonnage dried because of large
variations in the initial moisture content of the coal. Furthermore, Mr. Kerch stated
that CONSOL may not have data on tonnage dried for the recent tests. He also
suggested that the emission factor for VOC should take into account the volatile
material content of the coal. In their February 16, 1993 response to the draft
AP-42 section, the National Coal Association (NCA) also recommended that
emission factors be expressed in units of mass emitted per heat input for all
pollutants except PM and VOC, for which they recommended units of mass
emitted per mass of coat dried. I am also faxing a copy of NCA's comments
! checked the emission test reports in the background file and none of them
include data on heat input for the tests, so they would not be usable if we were to
express factors in units of mass emitted per heat input.
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STACK GAS PARAMETERS:
Gas Flow, OSCPM
Firing Rate, Ib/hr
Firing Rate, Ib/MMBtu
C0a,%
0,,%
P ARTICULATE EMISSIONS:
Gralns/dsef
Ib/hr
Ib/MMBtu
CO EMISSIONS:
ppmv
Ib/hr
Ib/MMBtu
NOx EMISSIONS:
ppmv
Ib/hr _ """"""'te*-,
to/MM Btu (O, based)
SO, EMISSIONS:
ppmv
Ib/hr
Ib/MM Btu (02 based)
E sllmated Removal, %
TOTAL VOC EMISSIONS;
ppmv
Ib/hr
Ib/MM Btu (0, based)
NON-METHANE VOC EMISSIONS:
ppmv
Ib/hr
ib/MM Btu (O, baaed)
66796
4527
64.0
2.6
17,6
0^)21
11.8
0.18
449
130
2.09
75
35
*~°^ 0,55
179
118
1,84
11,8
9.6
4.4
0.06
9,6
4,4
0.06
10/18/94
66798
4527
64.0
2.6
17.6
46
22
0,35
10/19/94
69400
461 \
65.1
2.7
17.7
0.024
14.6
022
404
123
1,69
60
29
0.47
171
118
1,82
12.8
9.8
4.7
0.07
9.8
4,7
0,07
10/19/94
67400
4341
61 J
2.6
17.8
0,027
15.7
0.26
406
120
196
172
11S
1.18
9.6
117
5.4
0,08
11.7
5.4
0,08
10/20/94
66800
4187
59.1
2.5
17.9
0.022
12.6
0.21
400
118
199
59
28
0.47
157
105
1,78
13.6
9.7
4.5
0.08
9.7
4.5
0.08
10/20/94
66800
4187
59.1
2,5
17.9
•_
407
120
1.96
9.9
4.6
0.08
9.9
4.6
0.08
AVG
67599
4417
62.4
2.7
173
0,024
13.7
022
419
122
1.97
60
28
0.46
170
114
1J3
11J
10.1
4.7
0.07
10.1
4.7
0.07
SDEV
1234
190
2.7
0,1
0,1
0.003
1.8
0.03
20
6
0.05
11
5
0.09
9
6
0.04
1.8
0,9
0.4
0.01
0.9
0,4
0,01
PRSD
1.8%
4.3%
4,3%
4.9%
0.7%
11.3%
18.1%
13.5%
4.9%
3.9%
2.6%
19,1%
19,0%
18.7%
5.4%
5.4%
2.3%
14,»%
fl.7%
8,4%
12.1%
8.7%
8.4%
12.1%
0:WPPRES\STACKV
\SE-SUMM
01/30/95
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MIDWEST RESEARCH INSTTTUT1
Suite 35
401 Harrison Oaks Boulavai
Gary, North Carolina 27513-241
Telephone (919) 677-024
FAX (919) 677-006
March 8, 1993
Mr. Neville Holt
Electric Power Research Institute
3412 Hillview Avenue
Palo Alto, California 94304
Dear Mr. Holt:
Thank you for the information you provided in a telephone
conversation with me on February 26, 1993. Enclosed are two
copies of a contact report summarizing the information discussed.
The information that you provided will be used in preparing
a revised section on coal conversion for the publication
Compilation jaf Air Pollutant Emission Factors, otherwise known "as
AP-42. To ensure the accuracy of the information, please review
the enclosed report and mark any changes you believe are
necessary to make the information accurate, complete, and
nonconfidential. Return to me one copy that you have signed and
dated, and retain one copy for your records. A final version of
the report, incorporating any changes you request, will be placed
in the background file for the AP-42 section. If we have not
received a response from you by March 24, 1993, the report will
be considered final and, nonconfidential and will be placed in the
project files that will be made available to the public.
Thank you for your review of this report. If you have any
questions, please call1 me at (919) 677-0249, extension 5359.
Sincerely,
"Marinshaw
Environmental Engineer
Enclosures
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CONTACT REPORT—MRI Project No. 3612
From: Richard Marinshaw, Environmental Engineering
Department
Date of Contact: February 26, 1993
Contacted by: Telephone
Company/Agency: Electric Power Research Institute
3412 Hillview Avenue
Palo Alto, California 94304
Telephone Number: (415) 855-2503
Person(s) Contacted/Titleis)
Neville Holt
CONTACT SUMMARY:
Mr. Holt was contacted for information on coal gasification.
Mr. Holt stated that only three coal gasification plants
currently are in operation in the United States. These plants
are located in Louisiana, Tennessee, and North Dakota. However,
many new coal gasification plants are under design through the
.Department of.Energy's Clean Coal Demonstration Project.
The Electric Power Research Institute (EPRI) has conducted
research on emissions from coal gasification processes. The
results of this research are included in two reports (GS-6806 and
AP-5931), which can be obtained through EPMI's distribution
center (Telephone: [510] 934-4212).
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