EPA-450/3-85-020
Kraft Pulp Mills —
Background Information for Promulgated
Revisions to Standards
Emission Standards and Engineering Division
U.S. ENVIRONMENTAL PROTECTION AGENCY
Office of Air and Radiation
Office of Air Quality Planning and Standards
Research Triangle Park, North Carolina 27711
May 1986
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This report has been reviewed by the Emission Standards and Engineering Division of the Off ice 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
Qffice(!vlD-35}, U.S. Environmental Protection Agency, Research Triangle Park, N.C. 27711»or from National Technical
Information Services, S285 Port Royal Road, Springfield,;Virginia 22161.
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ENVIRONMENTAL PROTECTION AGENCY !
Background Information and Final Environmental Impact, Statement
for Promulgated Revisions to Standards
- Kraft Pulp Mills -
Prepared by:
R. Tarmer
Firector, Emission Standards and Engineering Division
U.S. Environmental Protection Agency (MD-13) ;
Research Triangle Park, North Carolina 27711
1. The promulgated standards of performance will limit emissions of
particulate matter and total reduced sulfur (TRS) from new, modified, and
reconstructed kraft pulp mills. Section 111 of the Clean Air Act
(42 U.S.C. 7411), as amended, directs the Administrator to establish
standards of performance for any category of new stationary source of air
pollution that "... causes or contributes significantly to air pollution
which may reasonably be anticipated to endanger public health or welfare.11
2. Copies of this document have been sent to the following Federal
Departments: Labor, Health, and Human Services, Agriculture, Commerce,
Interior, and Energy; the National Science Foundation; the Council on
Environmental Quality; State and Territorial Air Pollution Program
Administrators; EPA Regional Administrators; Local Air Pollution Control
Officials; Office of Management and Budget; and other interested parties.
3. For additional information contact:
Mr. Doug Bell
Standards Development Branch
Emission Standards and Engineering Division (MD-13)
U.S. Environmental Protection Agency
Research Triangle Park, North Carolina 27711
Telephone: (919) 541-5578 :
4. Copies of this document may be obtained from: !;
U.S. Environmental Protection Agency Library (MD-35)
Research Triangle Park, North Carolina 27711
Telephone: (919) 541-2777
National Technical Information Service
5285 Port Royal Road
Springfield, Virginia 22161
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LIST OF TABLES
Table Page
2-1 List of Commenters : 2-2
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Volume II BID for Kraft Pulp Mills
TABLE OF CONTENTS
Section ! Page
1 Summary 1-1
2 Summary of Public Comments 2-1
2.1 Selection of Emission Sources for Control 2-4
2.1.1 Recovery Furnace Systems ; ' 2-4
2.1.2 Black Liquor Oxidation Systems 2-4
2.2 Emission Control Technology 2-5
2.2.1 Brown Stock Washers ; 2-5
2.2.1.1 Vacuum Drum Washers ; 2-5
2.2.1.2 Diffusion Washers 2-7
2.2.2 Recovery Furnace Systems 2-9
2.2.2.1 Noncontact Recovery Furnaces with 2-9
Wet-Bottom ESP's
2.2.2.2 Degradation of Performance of ESP's 2-11
2.3 Selection of Emission Limits 2-14
2.3.1 Smelt Dissolving Tanks ; 2-14
2.3.2 Lime Kilns 2-19
2.4 Test Methods and Monitoring 2-24
2.4.1 Temperature Monitoring Requirements 2-24
2.4.2 Revised Units for Smelt Tank Compliance 2-25
Calculations ,
2.4.3 Determination of Compliance with TRS 2-25
Standards
2,5 Reporting and Recordkeeping 2-26
2.6 Miscellaneous 2-27
Appendix A: Process Flow Diagram A-l
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1. SUMMARY
On January 19, 1984, the Environmental Protection Agency (EPA)
proposed revisions to the standards of performance for kraft pulp mills
(49 FR 2448) under authority of Section 111 of the Clean Air Act. Public
comments were requested on the proposal in the Federal Register. There
were 19 commenters composed mainly of industry representatives. Also
commenting were two regulatory agencies. The comments that were submitted,
along with responses to these comments, are summarized in this document.
The summary of comments and responses serves as the basis for the revisions
made to the standard between proposal and promulgation.
1.1 SUMMARY OF CHANGES SINCE PROPOSAL \
Since proposal, the Agency has reviewed new information and now concludes
that it is appropriate to exempt diffusion washers from the total reduced
sulfur (TRS) standard for brown stock washer systems. Uncontrolled TRS
emissions from diffusion washers are less than 0.001 Ib TRS per ton of
air-dried pulp (Ib TRS/TADP). This level is orders of magnitude less
than that of uncontrolled vacuum drum washers (0.3 Ib TRS/TADP) and is
also many times lower than the mass equivalent of the NSPS, The equivalent
mass emission rate for the 5 ppm NSPS, based on the vacuum drum washer,
is about 0.09 Ib TRS/TADP. Because of the low mass of TRS emissions
controlled and the low air volumes treated, requiring control of TRS
emissions from diffusion washers to the 5 ppm TRS level would result in a
cost effectiveness (C/E) in the range of $240,000 per ton of TRS removed.
Therefore, the Agency has determined that requiring diffusion washers to
meet the 5 ppm TRS standard would be unreasonable.
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1.2 SUMMARY OF IMPACTS OF PROMULGATED ACTION
1.2.1 Alternatives to Promulgated Action •
The regulatory alternatives are discussed in Chapter 6 of the •
Background Information Document (BID) for the proposed standards. These
regulatory alternatives reflect the different levels of emission control
from which one is selected that represents the best demonstrated technology,
considering costs, nonair quality health, and environmental and economic
impacts for kraft pulp mills. These alternatives remain the same.
1.2.2 Environmental, Economic, and Energy impacts of Promulgated Action
Environment impacts are summarized in Chapter 9 of the BID. The
decision to exempt diffusion washers from the new source performance standards
(NSPS) for brown stock washers will cause no increase in TRS emissions
because uncontrolled mass emissions of TRS from diffusion washers are
orders of magnitude less than controlled emissions of TRS from vacuum
washer systems. With the change noted in this section, the analysis of
environmental impact in Volume I of the BID now becomes the final Environmental
Impact Statement of the promulgated revision of the standards.
Economic impacts are summarized in Chapters 1 and 9 of the BID. The
cost of controlling TRS emissions from diffusion washers was previously
estimated to be $900 per ton of TRS removed. Estimated control costs,
which take into consideration new information on actual mass emissions,
are now estimated to range as high as $240,000 per ton of TRS removed.
Such costs far exceed control costs for typical NSPS,
Exemption of diffusion washers from NSPS may produce a minor reduction
in commitment of scarce resources such as chromium. Incineration of the
somewhat corrosive vent gases requires that materials of construction
such as stainless steel be used to construct ductwork to convey the gases
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to a point of incineration. The costs of these materials and the low
volume of gases are the major contributors to the high control costs
cited above.
Since the uncontrolled TRS emissions from diffusion washers are
lower than those from controlled vacuum drum washers, no adverse urban or
community impacts will occur due to the exemption of diffusion washers
from the TRS standard.
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2. Summary of Public Comments
A total of 28 letters commenting on the proposed revisions to the
NSPS for kraft pulp mills were received. A public hearing on the proposed
standards was not held because one was not requested. A list of commenters,
their affiliations, and the EPA docket number assigned to their correspondence
is given in Table 2-1.
For the purpose of orderly presentation, the comments have been
categorized under the following topics:
1. Selection of Emission Sources for Control r
2. Emission Control Technology
3. Selection of Emission Limits
4. Test Methods and Monitoring
5. Reporting and Recordkeeping
6. Miscellaneous i
The comments, the issues they address, and EPA's responses are discussed
in the following sections of this chapter. Changes to the regulations
are summarized in Subsection 1.2 of Chapter 1.
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TABLE 2-1 LIST OF COMMENTERS ON PROPOSED STANDARDS
OF PERFORMANCE FOR KRAFT PULP MILLS
Docket Item No.a Commenter and Affi11 ation
IV-D-1, 2, 10 and 12 Dr. John Pinkerton
National Council of the Paper Industry
for Air and Stream Improvement (NCASI)
260 Madison Avenue ,
New York, NY 10016 !
IV-D-3, 14, 20, 21, Mr. Russell Blosser
24, and 26 NCASI
260 Madison Avenue •'
New York, NY 10016 ;
IV-D-4 Mr. Donald Arkell !
Lane Regional Air Pollution Authority
1244 Walnut Street :
Eugene, OR 97403
IV-D-5 Mr. David Pattee
International Paper Company
International Paper Plaza
77 West 45th Street ,>
New York, NY 10036
IV-D-6 Mr. A. D. Whitford :
Longview Fibre Company
Longview, WA 98632 •
IV-D-7 Mr. Dan Sjolseth
Weyerhaeuser Company
Tacoma, WA 98477
IV-D-8 Dr. John Festa \
American Paper Institute
1619 Massachusetts Avenue, NW
Washington, DC 20036
IV-D-9 , Mr. Michael Roberts ;
Boise Cascade Corporation
1600 S.W. 4th Avenue
P.O. Box 1414
Portland, OR 97207
IV-D-11 ' Mr. Harry Hovey, Jr.
New York State Department of Environmental
Conservation
50 Wolf Road
Albany, NY 12233-0001
IV-D-13 Mr. R. F. Cashen
St. Regis Paper Company
Gulf Life Tower
Jacksonville, FL 32207
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Docket Item No.a Commenter and Affiliation
IV-D-15 Mr. Joe 6. Land, Jr.
International Paper Company
P.O. Box 999
Mansfield, LA 710S2
IV-D-16 Mr. John S. Carter
Georgia-Pacific Corporation
133 Peachtree Street, NE
P.O. Box 105605
Atlanta, GA 30348
IV-D-17 Mr. T. 0. Andrews
Hammermill Paper Company
1540 East Lake Road
Erie, PA 16533
IV-D-18 Mr. Dennis Ross
Boise Cascade Corporation
P.O. Box 500
Wallula, WA 99363
IV-D-19 Mr. Q. A. Narum
Simpson Paper Company
P.O. Box 637
Anderson, CA 96007
IV-D-23 Mr. Alan Lindsey
International Paper Company
International Paper Plaza
77 West 45th Street
New York, NY 10036
IV-D-25 Mr. Frank B. McGinley
Tennessee River Pulp and Paper Company
P.O. Box 33
Counce, TN 38326
IV-D-27 Mr. Larry Pattengill
International Paper Company
P.O. Box 999
Mansfield, LA 71052
IV-0-28 Mr. J. L. Zuncich
Federal Paper Board Company, Inc.
Riegelwood, NC 28456
aThe docket number for this project is OAQPS A-82-36. Dockets are on
file at EPA Headquarters in Washington, D.C., and at the Office of Air
Quality Planning and Standards in Durham, N.C.
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2.1 SELECTION OF EMISSION SOURCES FOR CONTROL
2.1.1 Recovery Furnace Systems
Comment (IV-D-4). One commenter suggested that further consideration
be given to requiring S02 controls on recovery furnaces. The commenter
does not consider the estimated control cost of $3,000 per ton to be
atypical for NSPS controls.
Response; The EPA is not aware of any instance in which flue gas
desulfurization (FGD) has been installed to control sulfur dioxide (S02)
emissions from a recovery furnace. Thus, there is no data base available
upon which accurate estimates of costs and performance can be made. The
estimated cost of $3,000 per ton of S0£ removed presented in the preamble
was derived from control cost information for industrial boiler FGD
systems. Although the S02 control methodology which was examined is
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applicable to recovery furnaces, any cost projections which have been
calculated are subject to the uncertainty inherent to the transfer of
technology from one industry to another. Since the estimated cost per
ton of S0£ is in the uppermost range of control costs for NSPS and, since
there is now uncertainty as to the true value of that cost, the Agency
cannot conclude that there is a best demonstrated technology, considering
cost, which would be applicable for S02 control at all new recovery
boilers.
2.1.2 Black Liquor Oxidation (BLO) Systems
Comment (IV-D-5 and 8): Two commenters support the exemption of
BLO Systems from TRS controls.
Response; None required.
Comment (IV-D-4 and 11): Two commenters oppose exemption of BLO
systems from TRS controls. Both state that the possible 42 percent
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increase in total TRS emissions from an individual facility can create
unacceptable problems for a community and cannot be considered a minor
change. Both commenters also state that control technology is available
and should be required in spite of being somewhat expensive.
Response: As was discussed-in the proposed revision (49 FR 2451-2),
the estimated control cost of $9,200 per ton of TRS is unreasonable for
a national standard. In the instance to which the commenters referred,
the possible increase in emissions is substantial (42 percent) in comparison
with total controlled TRS emissions and could conceivably create unacceptable
odor problems for individual communities. For example, if a new facility
is located at a site in close proximity to older, less effectively controlled
facilities, the overall impact of a new uncontrolled BLO system may be
unacceptable. In such instances, State and local agencies do have the
authority and prerogative of establishing standards more stringent than
NSPS.
2.2 EMISSION CONTROL TECHNOLOGY
2.2.1 Brown Stock Washers
2.2.1.1 Vacuum Drum Washers
Comment (IV-D-4 and 11): One commenter objected to continued
provisions for exemption from incineration requirements for vacuum washers
when excessive control costs can be demonstrated. They state that poor
mill design, which requires that vacuum washers be installed some distance
from an incineration device, is not reasonable cause for an exemption
from control requirements, A second commenter said that emissions from
diffusion washers may meet the standards without a control device and
that EPA should carefully review any requests for vacuum washers where
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diffusion washers could be installed. {
Response: The provision for exemption from incineration requirements
in the existing regulations is being kept because of difficulties which
may arise when new vacuum drum washers are installed in existing facilities.
The design of some existing recovery furnaces is such that the high
volumes of gas given off by vacuum washer systems cannot be' introduced to
those furnaces without creating the potential for explosions to occur.
In some cases existing plant layouts may preclude the installation
of additional washer systems in an area near the recovery furnaces or
power boilers. Without the exemption, ductwork lengths at existing mills
could range up to 1,500 feet in length. Because the gases given off by
vacuum washers have a high moisture content and contain sodium salts,
such ductwork costs must include provision for corrosion-resistant materials
of construction, with attendant high costs. A guideline document published
by EPA in 1979 for control of TRS emissions at existing ;kraft pulp mills
estimated costs for controlling brown stock washers at four times higher
than control costs for new mills. These control costs for existing
washer systems were considered unreasonable at that time and no emission
guideline was recommended. Updated control costs for existing washers
would be about $10,000/ton of TRS, which is considered unreasonable for
this national standard.
With regard to diffusion washers, the Agency agrees with the second
commenter. Elsewhere in this document, emissions from diffusion washer
systems are discussed in detail and a conclusion is reached that these
systems typically have very low mass emissions of TRS compared to vacuum
drum systems. Therefore, EPA will carefully review requests for exemptions
from NSPS for vacuum drum washers to insure that available alternatives
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have been explored and to ascertain that an exemption is necessary.
Comment; (IV-D-2, 8, 10 and 17): Three different commenters support
retention of the existing provisions for exemption from incineration
requirements for new or modified brown stock washer systems on a case-by-
case basis,
Response; None required.
2.2.1.2 Diffusion Washers
Comment (IV-D-1, 4, 5S 8, 10, and 11): Two comments contain the
findings and resulting recommendations of a study performed by an industry
council to quantify TRS emissions from diffusion washers. That study
examined 9 diffusion washer vents and the mean mass emission pate was
found to be 0.001 lb., or less, TRS/TADP. Such emission levels are two
orders of magnitude less than those from uncontrolled vacuum drum washer
systems. Using the same cost estimating procedures employed by EPA for
the case of vacuum drum washer systems, the industry calculated the C/E
of further controlling these emissions to be $240,000 per ton of TRS
removed. Three commenters said that those findings preclude EPA from
reasonably supporting the need to control diffusion washer vent gases on
an emission significance or economic basis. They note that there would
be no advantage to setting mass emission limits and that imposing measurement
and reporting requirements would be burdensome. Two commenters support
the above findings and conclusions. One commenter noted that diffusion
washers may meet the existing standards without a control device.
One commenter disagrees with the others and says that diffusion
washers should not be exempted outright from having TRS controls. This
conimenter believes each individual source should be required to demonstrate
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that emissions from its uncontrolled diffusion washers tan meet the same
TRS standards as controlled vacuum washers. '.
Response: The study submitted on TRS emissions from diffusion
washers has been reviewed by the Agency. The Agency agrees that uncontrolled
TRS emissions from diffusion washers are less than 0.001 1b TRS/TADP. -
This level is orders of magnitude less than that of uncontrolled
vacuum drum washers (0.3 Ib TRS/TADP) and is also many times lower
than the mass equivalent of the NSPS. The equivalent mass emission rate
for the 5 ppm NSPS, based on the vacuum drum washer, is about 0.09 Ib TRS/TADP,
Because of the low mass of TRS emissions controlled and the low
air volumes treated, requiring control of TRS emissions from diffusion
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washers to the 5 ppm TRS level would result in a C/E in'the range of
$240,000 per ton of TRS removed. Therefore, the Agency has determined
that requiring diffusion washers to meet the 5 ppm TRS standard would be
unreasonable.
For several reasons, revision of the NSPS to a mass equivalent TRS
standard would also be unreasonable. As the available data indicated,
uncontrolled TRS emissions from diffusion washers are many times lower
than the mass equivalent of the NSPS. As such, requiring diffusion
washers to demonstrate compliance with a mass equivalent NSPS would
impose unnecessary costs for testing and reporting requirements. In
addition, an EPA reference sampling method would have to be developed and
promulgated since the present EPA Reference Method 1 is insufficient for
sampling the low velocity, low volume, and cyclic gas stream emitted from
a diffusion washer.
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Development of a separate standard for TRS emissions from diffusion
washers would require a major commitment of Agency resources to study a
process which produces very low mass emissions. Such a standard would
have to include a control technology which, in this case, would undoubtedly
be incineration and the cost has been estimated to be in the range $240jOOO
per ton of TRS removed. Because projected control costs are high and potential
benefits are negligible, the Agency has concluded that development of NSPS
for TRS emissions from diffusion washers is not appropriate.
2.2.2 Recovery Furnace Systems
2.2.2.1 Noncontact Recovery Furnaces with Wet-Bottom Electrostatic
Precipitators (ESP's)
Comment (IV-D-3, 4, 5S 8, 10, 11, 16, 17 and 21): Seven different
commenters agreed with the EPA proposal to delay completion of the review
of the existing TRS standards for recovery furnace systems as they pertain
to facilities which have installed wet-bottom ESP's. All agreed that any
possible changes which would take into consideration the performance of
noncontact recovery furnaces equipped with wet-bottom ESP's using unoxidized
black liquor should be delayed until the National Council of the Paper
Industry for Air and Stream Improvement (NCASI) has completed its studies
of these systems. One commenter noted that it has been demonstrated that
dry-bottom ESP's can achieve the existing TRS standard. They conclude
that any changes to the current TRS standard should pertain only to
wet-bottom ESP's and that any possible changes should be delayed only
until the NCASI study is complete. One commenter said that EPA should
resist any change in the existing standards and that EPA should explore
the use of non-TRS bearing water in the wet-bottom ESP's.
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Response: Since proposal, much work has been done by NCASI and by
individual affected firms in an attempt to fully understand and correct
the problem. The NCASI study has identified several factors which'are
contributing to the problem. These include inlet baffling design, liquor
temperature, liquor level, degree of agitation, and liquor chemistry. To
date, modifications to mitigate the first four factors ;hav'e been made in
most instances where they appeared feasible. The results of the modifications
differed from mill to mill and were not always successful for reducing
TRS emissions. Similarly, efforts by individual mills to control or
modify the chemistry of liquors used in the wet ESP's have given mixed
results. After making various combinations of modifications, some
facilities have achieved, or have come very close to achieving, the 5 ppmv
TRS standard. However, according to industry assessments, several furnaces
appear unable to consistently-achieve better than 15 ppm and some appear
unable to consistently achieve better than 25 ppm while using unoxidized
black liquor in the ESP.
The EPA has reviewed available data and the steps which industry have
taken. It is clear from this that NCASI and individual firms have expended
considerable resources in their attempts to identify and correct the
causes of TRS release from unoxidized black liquor used in wet-bottom
ESP's. The Agency agrees that the recovery furnace TRS- standard is
probably not consistently achievable at all sources when such liquor is
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used in the ESP's. However, based on its review of the1industry studies,
the factors which are causing excess emissions, and of potential remedies,
EPA has concluded that the standard for recovery furnace TRS emissions
should not be revised. In reaching this conclusion, the Agency recognizes
that the decisions to install the wet-bottom precipitators were made
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based on the available industry data which indicated that the TRS emission
limit would not be violated. But, there were other options available and
those options were employed at other facilities. Furthermore, retrofit
options are available which will allow the sources with wet-bottom ESP's
to achieve compliance with the TRS emission limit. For example, two "
mills have made piping changes which allow them to use fresh water in
wet-bottom ESP's and the level of the NSPS for TRS has been achieved. In
addition, mills have the option of converting the bottoms of their ESP's
from the wet to the dry design. Although each of these options entails a
retrofit with annualized costs ranging from $85,000 to $275,000 per mill
and the associated TRS reduction could be small, EPA believes the costs
of the retrofits are reasonable. When the annual!zed cost of installing
and retrofitting a wet-bottom ESP are compared to the annualized costs of
initially installing a dry-bottom ESP, the net difference in estimated
annualized costs of retrofitting the wet-bottom ESP are reasonable and
range from a savings of $40,000 to a cost of $100,000.
In conclusion, therefore, the Agency believes that changes to the
NSPS for kraft recovery furnaces would be inappropriate and that those
mills now out of compliance with the TRS standard should take the necessary
steps to achieve compliance in a timely manner.
2.2.2.2 Degradation of Performance of ESP's
Comment (IV-D-8, 10, and 13): Three commenters disagree with the Agency's
conclusion in the BID that data from a 9 year old ESP show that ESP's can
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reduce recovery furnace particulate emissions to NSPS levels over a long
period of time when they are properly maintained. One commenter operates
the ESP to which the three referred and this commenter says the data show
that, even with maintenance, the ESP is not capable of achieving NSPS
consistently. The commenter also said that it is inappropriate to draw
conclusions about long-term performance of ESP's from data'obtained from
only one ESP.
A second commenter said that the data provided by the previous
commenter clearly show an upward trend in emissions of PM with increasing
age of the ESP and that EPA's judgment concerning the ability of ESP's to
meet NSPS for particulate emissions over the long term is an inappropriate
interpretation of data from a single location. The commenter presented
long-term data from two other sources with ESP's designed to achieve
emission levels similar to NSPS and said the data from all three sources
showed an upward trend in particulate emissions with increasing age of
the ESP's. The data from all three ESP's also showed that measured
emissions following major rebuilds of the ESP's were significantly higher
than those achieved when the precipitators were new. The commenter
attributed the increased emissions to such factors as buildups and corrosion
in duct work, plenums and turning vanes, which can cause flow maldistributions,
The second commenter maintains that EPA has not thoroughly investigated
the ESP degradation issue in its NSPS review. They also say that the
Agency has not considered the costs of major rebuilds or lost production
due to unscheduled repairs in the C/E calculations.
Response: The problem of gradual deterioration of ESP performance
was investigated during the NSPS development and again during the NSPS
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review. During the NSPS development, the ESP vendors indicated that a
properly maintained ESP should not deteriorate over the expected life of
the unit. Problems encountered are usually due to operating the equipment
at conditions for which it was not designed (i.e., higher gas volumes,
higher inlet loadings, or lower inlet temperature). The main problem
areas are corrosion and wire breakage.
The unit for which EPA obtained long-term particulate data, at the
time it was installed, employed a new design which minimized wire breakage.
This unit was tested by EPA as part of the data base for the NSPS.
Additional data supplied by the State agency during the NSPS development
indicated that the unit consistently achieved the NSPS level. During the
NSPS review, the operator of this unit was again contacted to obtain
information on maintenance costs and ESP performance. The maintenance
costs for this unit had increased from 240 man-hours per year to an
average of 913 manhours per year. These maintenance costs are higher
than the estimate used by the Agency. If it could be shown that all of
these costs are attributable to the NSPS, the incremental C/E of the NSPS
is $200-$300 per ton, which is still reasonable. However, as noted, it
is not clear that the increased maintenance costs are in fact due to the
NSPS. The data indicated that after 10 years of operation, the unit was
still capable of achieving the NSPS level. It is true, as the one commenter
pointed out, that test data indicate that at times the unit has had
emissions above the NSPS level. It must be pointed out, however, that
this unit is not subject to the NSPS and is only required to achieve a
State regulation which is double the NSPS level. Therefore, this unit is
maintained to achieve the State level as opposed to the NSPS level. It
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is the Agency's judgment that this unit could consistently achieve the
NSPS if the frequency of maintenance were increased. The Agency's judgment
is supported by the data supplied by one commenter which shows the'performance
of an ESP which is not subject to the NSPS but which is subject to a
State standard about 25 percent lower than the NSPS. this latter unit
has been operating for 10 years and has consistently achieved the NSPS
levels.
The Agency's cost estimates do not include the cost of major rebuilds
as was suggested by the commenters. The ESP's were widely used in the kraft
pulp industry for recovery of process chemicals prior to establishment of
NSPS and none of the information which has been reviewed indicates that
major rebuilds are needed more frequently because of NSPS for PM. As a
result of NSPS, new ESP's are designed with more plate area and additional
maintenance costs for such items as replacement of broken wires would be
expected. However, the need for major rebuilds, to repair corrosion
damage, for example, is most likely attributable to process parameters,
such as the flue gas temperature, and not related to the sizing of the
ESP's. Since the NSPS do not affect the frequency of major rebuilds, it
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would be inappropriate to include the costs of rebuilds in the calculation
of control costs.
2.3 SELECTION OF EMISSION LIMITS ;
2.3.1 Smelt Dissolving Tanks (SDT) ;
Comment (IV-D-5, 7, 8, 9, 10, 15, 18, 22, and 27): Five different
commenters were in agreement with EPA's decision to raise the TRS standard
for SDT. However, they said that the increase should be greater than the
one which was proposed. One commenter said that preliminary data from a
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new mill indicated that the proposed level needed to be doubled. In a
follow-up letter, the commenter described the liquids being used in their
scrubbers and noted that they planned to try and redirect sulfide-cbntaining
recycle streams from the SDT and scrubbers. In a third letter, the
commenter said that efforts to modify their piping system to redirect
sulfide bearing liquids away from the smelt tanks had been successful and
that they had passed compliance tests. Thus, they withdrew their request
for a higher TRS limit than that which was proposed.
A second commenter sent two letters describing experiences at two
of its mills. The commenter said that selection of the scrubbing liquid
is the only known method of modifying TRS emissions associated with smelt
tank vent gases. The commenter has examined the use of alternative
scrubbing liquids and said that TRS emissions exceeded the standard even
when fresh water was used in the scrubbers at one of the mills. They
said their best results at the other mill were obtained when both the
smelt tank scrubber and the lime kiln mud washer showers were operated on
fresh water, which the commenter considers an artificial condition for
that particular mill. The commenter submitted additional continuous
monitoring data and said the new data showed variations similar to those
in previously submitted information.
A third commenter said the proposed TRS level is a move in the
right direction, but that two of its facilities cannot meet that level on
a consistent basis. The commenter said that various scrubbing media had
been tried but that no controllable process or control technology operating
conditions had been identified which could limit TRS emissions from smelt
tank vents. This commenter said its data (from 50 hours of continuous
monitoring) supported a TRS limit well above the proposed level. Two
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comments by industry trade associations supported the first three commenters1
observations and comments.
Response; Bnissions of TRS compounds are governed by the concentration
of reduced sulfur compounds either in the smelt from the recovery furnace
or in the water in the smelt tank. . Additional TRS may be introduced if
liquids contaminated with TRS compounds are introduced to the scrubbers
used for control of PM. There is no means of controlling the introduction
of reduced sulfur compounds via the smelt from the recovery furnace.
However, the introduction of additional TRS compounds to the vent gases
can be prevented, or substantially reduced, by the selection of liquids
to be used in the tanks and scrubbers. Preventing the Introduction of
TRS-contaminated liquids to the SOT system is the basis of best demonstrated
technology (BDT), which is, "to use a liquid that is low in sulfides and
TRS compounds—such as fresh water or recycled water from the lime mud
washer—in the smelt tank and particulate control device" (49 FR 2448).
The data base used in the review to revise NSPS for TRS from 0.0084 g/kg
of black liquor solids (g/kg BLS) to 0.016 g/kg BLS includes two test
reports from one mill which failed to comply with the 0,0084 g/kg BLS
emission limit. The operators of the mill indicated that they had used
fresh water in their mud washers and that the weak wash had been used in
both the smelt tank and scrubbers. Use of these types of liquids is
considered to be BOT for reducing TRS emissions. They then experimented
with various liquids in the scrubber, including fresh water. Since no
reasons for the higher TRS emissions could be identified, and since the
sources were applying BDT, the emission limit for TRS emissions was
proposed to be raised to 0,016 g/kg BLS to reflect the results of these
compliance tests.
2-16
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Information supplied by the first commenter showed that relatively
small flows of TRS-contaminated recycle streams were being introduced to
the weak wash storage tanks and subsequently to the SDT's and scrubbers.
The operators of the mill were reluctant to remove the recycle streams
because they did not want to increase either water usage or the amount
of wastewater to be treated. When the mill used BDT and removed the TRS
contaminated liquids from the smelt dissolving system, they did pass
tests for compliance with the current TRS standard. After passing the
test, the commenter withdrew his initial comment that the TRS limit should
be greater than 0.016 g/kg BLS.
The data supplied by the second commenter for one of their mills
showed that they had been using contaminated condensate in their SOT
scrubber recycle system. When the condensate was replaced with fresh
water, TRS emissions began to drop. Later data from the same source
showed that use of boiler blowdown (which is very low in residual sulfides)
in the system reduced TRS emissions to NSPS levels. The commenter said
that the best results were obtained when lime mud shower (which produces
the weak wash used in the SDT) and SOT scrubber were operated on fresh
water, but that this represents an artificial condition established
solely to minimize TRS emissions. They say that operating in this manner
causes an unusually high hydraulic loading on the effluent treatment
system. The artificial condition described for the plant is what the
Agency considers to be BDT. While the plant may not operate this way
now, the Agency has concluded that using fresh water, or other liquids
low in TRS compounds, to reduce TRS emissions is technically feasible and
reasonable from a cost standpoint. The Agency continues to believe that
if BDT is implemented, the TRS limit of 0.016 g TRS/kg BLS can be met.
2-17
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The EPA disagrees with the second cofnmenter's statement that selection
of scrubbing liquid is the only known method of modifying TRS emissions
associated with SOT vent gases. The mill which they were discussing had
problems with excess TRS emissions and began testing different scrubbing
liquids. Initially, they had been -using weak white liquor, which is
known to remove some polar .compounds, such as H2S. Thus, it is not
surprising that TRS emissions increased when water, and various other
liquids were substituted. However, the scrubber was installed for removal
of PM, not TRS. The key point is that BDT for TRS is aimed at preventing
introduction of TRS to vent gases by the dissolving liquid or scrubbing
medium.
Both the second and third commenters said that the; ranges in their
TRS monitoring data were indicative that the proposed standard cannot be
met on a consistent basis. The third commenter did not submit enough
information for the Agency to draw any conclusions. It is noted that the
two tanks to which they referred are not subject to NSPS and the comment
letter suggested that water used in the SOT was not of the quality required
by BDT. The second commenter's data showed variation in TRS concentrations
for individual samples, but when the data points were averaged, as they
would be for a compliance test report, the emission levels were below the
proposed TRS limitations.
Comment (IV-D-4, 11): Two commenters object to relaxing the existing
TRS standard for SOT because of one or two failures to achieve compliance.
One commenter suggests an alternative of allowing exemptions based upon
site-specific studies and a requirement that Best Available Control
Technology be employed.
2-18
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Response: These suggestions are inconsistent with the basis of the
NSPS. An emission limit must be set at such a level that any facility
which employs BDT can achieve that emission level during a performance
test. A facility which was employing BDT failed two performance tests.
In selecting an emission limit, variability of available test data must
be taken into consideration. The Agency proposed to revise the TRS
standard from 0.0084 g/kg BLS to 0.016 g/kg BLS in order to reflect the
observed performance of BDT.
The TRS compounds may be introduced to the vent gases by the
molten smelt, the water in the smelt tank or the liquid used in the
particulate scrubbing device. There is no means of controlling the;
amount of TRS introduced by the smelt and there is no BDT for removing
TRS from SDT vent gases. However, the sulfide content of the water used
in the SDT and scrubber may be readily controlled and this is the basis
for the BDT. Hence, BDT for controlling TRS emissions from SDT is to use
a liquid that is low in sulfides, such as fresh water or recycled water
from the lime mud washer, in the SDT and scrubber.
2.3.2 Lime Kilns
Comment (IV-D-4): One commenter suggested that the standard for
PM should be made more stringent. The commenter said that EPA should
give further consideration to requiring ESP's in series with venturi
scrubbers and that the $3,200 per ton cost estimate is not out of line
with the typical cost range for NSPS controls quoted in the text.
Response: The C/E of an ESP in series with a scrubber to which
the commenter refers was calculated based on cost estimates generated
when the current NSPS was developed. The $3,200/ton C/E estimate is for
an oil-fired lime kiln. Kilns subject to the NSPS are generally designed
2-19
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to fire both gas and oil. However, most of those kilns, subject to NSPS
which were designed for both fuels are fired on natural gas. The C/E for
an ESP on a kiln firing gas is estimated at about $8,5QQ/ton. This is
because of the lower incremental emission reduction achieved by the
addition of an ESP when gas is fired. The NSPS for gas-fired kilns is
half the level for oil-fired kilns. Therefore, the C/E for1 any individual
lime kiln could vary between $3,200 and $8,500/ton depending on the
percent of time gas is fired in the kiln. Since the incremental C/E
would be higher than $3,200/ton in most cases, the Agency feels that it
would be unreasonable for the NSPS to require ESP's in Series with scrubbers,
Comment (IV-D-8, 9, 10, 16, 19, and 20): Five different commenters
suggest the current TRS standard for lime kilns needs to be revised to
reflect the results of continuous monitoring. One commenter says the
monitoring data from two of its NSPS facilities indicate that the standard
needs to be revised to allow for exceedance of the TRS limit 3 percent of
the reporting time to allow for normal variations in operating conditions.
The commenter lists four factors which can influence TRS emissions from
the kiln stack: (1) kiln firing conditions; (2) treatment of noncondensable
gases; (3) source of water used at the particulate scrubber; and (4)
porosity of the mud at the filter (which controls oxidation of the residual
1
sulfide content). This commenter stated that TRS emissions associated
with the first three factors are straightforward and the control options
are understood, but that the control of mud porosity at the filter is not
completely understood.
One commenter stated the opinion that the current TRS standard can
be met when the kiln and associated systems are operating normally, but
that the nature of the process is such that unavoidable irregularities
2-20
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which can affect TRS emissions will occur 10 percent or less of the total
operating time. He says that short-term "blips" or "spikes" are adequately
reckoned by the averaging time, but that a 4 percent allowance for excess
emissions appears reasonable for those infrequent, medium-term TRS .
excursions which are beyond the control of the operators. The commenter
says he is unaware of any evidence that the use of caustic'soda (to
control excess emissions) is effective and/or cost effective. He also
doubts that lime mud oxidation is a cost effective technique for controlling
excess TRS emissions.
One commenter has been unable to explain variations in data from a
certified continuous monitoring system. The commenter stated that 12-hour
averages from this particular facility range from 2 to 30 ppm TRS and the
commenter is concerned that it may not be possible to meet the 8 ppm
limit continuously.
One commenter says that as more TRS monitoring systems come on-line,
there will be additional information which will be useful in determining
whether or not the current standard is appropriate. The commenter suggests
that EPA should evaluate available continuous monitoring data from lime
kilns equipped with wet scrubbers before making any final decisions on an
NSPS.
Response; Many of the comments were prompted by the requirement that
lime kilns subject to the NSPS install and operate continuous emission
monitors (OEM's) to measure TRS emission by July 20, 1984. After considering
the comments, the Agency determined that it would be appropriate to
obtain additional data. Subsequently, the first 6 months' CEM data for
all 19 lime kilns subject to NSPS were requested along with associated
operational data and design parameters for the lime kilns and lime mud
2-21
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washing systems. The Agency has received additional information for
14 of the 19 lime kilns subject to the NSPS. Of the 14 submitting data,
3 were judged to be using BDT and had CEM data which were accompanied by
information needed to ascertain the accuracy of the certification reports.
The data from these 3 facilities indicate that the NSPS can be achieved
when BDT is implemented.
During the data period, one of the three mills had'only one excess
emission and the excursion occurred when the addition of caustic was
discontinued for testing of the CEM. A second mill, which previously
achieved the NSPS TRS limit a high percentage of the time through good
mud washing and process control, began using caustic in recent months.
The most recent excess emission reports show no excess emissions. The
i
Agency considers this information to be indicative that caustic addition
reduces excess TRS emissions. '•<
Approximately half of the remaining data could not be used in making
a decision because either data needed to determine if the OEM's had been
properly certified was missing or the information provided showed that
the CEM's had histories indicative of maintenance problems,, The data
from the rest of the mills were suggestive of failure tcl follow all of
the practices which constitute BDT.
In general, long-term CEM and operational data for NSPS lime kilns
show that the ability to reliably operate CEM's and use the CEM's for
process control plays a central role in the achievement of the NSPS and
that such ability is learned over time. The industry continues to believe
i
it is possible in some cases that, even with experience and the use of
BDT, there could continue to be periods of excess emissions. Although
such a possibility may not be ruled out, the Agency has not received any
2-22 •
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data which would indicate that such is the case. The Agency expects
that, as the operators of these facilities learn to use their CEM's to
aid in controlling their processes, the periods of excess emissions
should be significantly reduced when BDT is fully implemented.
Industry representatives have-expressed concern that reported excess
emissions may be construed as violations of the Clean Air Act. Compliance
or non-compliance with the Act is determined by performance testing. A
detailed description of the Agency's intended use of CEM data was previously
published in the Federal Register (43 FR 7568). The overall intent of
the requirement to continuously monitor TRS emissions is to provide enforce-
ment agencies with an instrument to determine that BOT has been implemented
and is being practiced.
Comment (IV-D-6 and 10): Two comments were received concerning
the lime kiln controlled with an ESP which was described in the Proposed
Rules. The commenters emphasized the uniqueness of this particular
facility, at which an ESP was installed to meet local and State particulate
limits which are site specific, and that an exemption should be granted for
this facility. One commenter requested that the NSPS TRS limit be revised
to require this particular facility to meet a TRS emission limit of
20 ppm corrected to 10 percent oxygen, on a 12-hour basis, and not to be
exceeded more than 2 percent of the time on a quarterly basis. The
commenter also said that the stack gases from the ESP would disperse
better than those from a venturi scrubber because the gases from the ESP
are approximately 180° hotter.
Response: The Agency has reviewed information on the lime kiln which
is controlled with an ESP instead of a wet scrubber. Information reviewed
2-23
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by the Agency suggests that this particular facility can control TRS
emissions to NSPS levels by making additional improvements in process
controls and by raising the temperature of the cold end of the lime kiln '
by 100° F. During the review, the costs of implementing BDT were reexamined.
These costs included the costs to increase cold-end temperatures, and
the Agency continues to believe these costs are reasonable.
2.4 TEST METHODS AND MONITORING
2.4.1 Temperature Monitoring Requirements <
Comments (IV-D-5, 8, 9, and 11): Four commenters favor the proposed
elimination of temperature monitoring requirements for lime kilns, power
boilers, and recovery furnaces. One commenter voiced agreement with the
decision to retain the temperature monitoring requirement for TRS incinerators
because they believe that these records can reveal excessive control
equipment downtime.
Response: None required.
Comment (IV-D-4): One commenter opposes the elimination of any
temperature monitoring requirements because they consider such requirements
to be a low-cost item which will ensure proper combustion of TRS emissions.
Response: The Agency proposed to eliminate temperature monitoring
requirements for power boilers, recovery furnaces, and lime kilns. The
basis of the proposal is that the flame temperatures and residence times
at which these facilities are expected to operate exceed the 1200° F and 1/2
second considered necessary for adequate incineration of TRS emissions.
The Agency also noted that implementation of requirements for continuous
2-24
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monitoring of TRS emissions from recovery furnace systems and lime kilns
provides additional justification for eliminating temperature monitoring
requirements for these sources. Further, prevention of energy waste
and of fouling of heat transfer surfaces in power boilers is sufficient
incentive for the owners of these facilities to properly operate and
maintain them. Therefore, the Agency considers temperature monitoring
requirements to be unnecessary.
2.4.2 Revised Units for Smelt Tank TRSCompliance Calculations
Comment (IV-D-8 and 11): Two commenters support the proposed revision
of the units of the TRS standard for smelt tanks. One of the commenters
suggests that a source which fails the performance test using Method 16A
should be required to retest using Method 16 because the latter procedure
provides more information as to why the source failed the test.
Response; It is the option of the source owner to test using the
Method 16 gas chromatographic procedure and only quantify hydrogen
sulfide,-methyl mercaptan, dimethyl sulfide, and dimethyl disulfide. If
the source owner chooses to use Method 16A, which measures all sulfur
compounds except S0£, and fails the performance test, the owner would
presumably re-test using Method 16. Therefore, it is not necessary to
provide this in the regulation.
2.4.3 Determination of Compliance with TRS Standards
Comment (IV-D-12): One commenter noted the need to correct the
formula for calculation of the TRS emission rate as given in
Section 60.28S(d)(3) of the NSPS for Kraft Pulp Mills which was promulgated
on February 23, 1978. When English units are used in the formula as it
was published, the resulting value of "E" is 500 times too large.
2-25
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Response: The commenter Is correct. A corrected formula was
printed in the Federal Register on March 8, 1985 (50 FR 9578) and on
May 6, 1985 (50 FR 19022).
2.5 REPORTING AND RECORDKEEPING
Comment (IV-D-5, 8, and 9): Three commenters favor the proposal to
change the frequency of excess emissions reporting from quarterly to semi-
annually.
Response: None required.
Comment (IV-D-4 and 11): Two commenters oppose the proposed change
in the reporting period. One commenter says the current requirement
imposes little burden on industry but provides significant improvement in
the data base used by controlling agencies. One commenter says that the
proposed change would make any response to excessive emissions more
difficult. '
i
Response; The proposed change in the reporting period will affect
neither the data base nor the usefulness of the data for identifying
periods of excess emissions. For example, continuous monitoring of TRS
emissions from recovery furnaces and lime kilns is required. Twelve (12)
hour average TRS concentrations (2 per day) must be calculated and recorded.
The proposed change in the reporting period would have no effect whatsoever
on these requirements and, thus, the data base will not,!be affected.
Also, the data which is gathered is not used to determine compliance with
the regulations. Rather, the data is used as an indicator of good process
operation and as a possible indicator of the need for compliance testing.
Although the Agency will receive data less often, we believe that semi-
annual reporting will be sufficient to insure proper operation and maintenance,
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2.6 MISCELLANEOUS
Comment (IV-D-10): One commenter made the following remarks regarding
the timeliness of the current procedures for reviewing NSPS: "New technologies
with significant potential for reduced emissions and energy consumption
as compared to conventional technologies are constantly under development
and may be ready for full-scale commercial application at any time.
However, several years typically elapse between EPA reviews of the NSPS
for a particular industry. Since existing NSPS may or may not be appropriate
for a given new technology, there is an urgent need for timely EPA review
and evaluation of new technologies as they come on-line. Appropriate
revisions to the NSPS should be made in an expeditious manner to accommodate
new technologies; EPA should not wait until the normally scheduled periodic
NSPS review is conducted." The commenter feels that the NSPS should not
be an impediment to the installation of new and/or lower emitting technologies,
Response; The NSPS do not require that operators of a facility
install a specific technology. Instead, the standards establish emission
limits which are achievable by the BDT. An operator is free to install
and operate any technologies if emissions do not exceed the limitations
of the applicable standards. An individual wishing to install an innovative
technological system, one which has not yet been adequately demonstrated,
may request a waiver under the provisions contained in Section lll(j) of
the Clean Air Act.
In those instances where major changes within an industry occur
between 4-year reviews, the industry may request that a special review of
NSPS be conducted if the need to do so can be demonstrated to the Agency.
Comment (IV-D-9): One commenter remarked that the EPA proposal to
allow the owner of a kraft pulp mill to select the control process for
2-27
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TRS emissions, so long as the 5 ppm TRS limit is met, for digester systems,
brownstock washer systems, and condensate strippers is ;a reasonable
position. This commenter notes that the owners of these facilities have
both the economic incentive and the expertise to comply with applicable
regulations. - i
Response; None required. i
2-28
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APPENDIX A
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T
0
z
E
o.
m
O
NONCONDENSABLES
WOOD
WHITE LIQUOR
{NaOH + Na£S)
DIGESTER
SYSTEM
WATER
f
WHITE LIQUOR
DIGESTER)
VENT GAS
RECOVERY
FURNACE
SYSTEM
SMELT
GREEN LIQUOR
1
»
CAUSTICIZING
TANK
fri«
HEAVY
BLACK
LIQUOR
AIR
T
SMELT
DISSOLVING
TANK
'
-
VENT GAS
PULP
WASHERS
PULP
WATER
BLACK LIQUOR
VENT GAS NONCONDENSABLES
BLACK
LIQUOR
OXIDATION
TANK
(OPTIONAL)
T
J
MULTIPLE
EFFECT
EVAPORATOR
SYSTEM
CONDENSATE
STRIPPER
SYSTEM
TO TREATMENT POND
CONDENSATE
-o
o
X
VENT GAS
CALCIUM
RBON
MUD
KRAFT PULPING PROCESS
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TECHNICAL REPORT DATA
(Please read Instructions on the reverse before completing}
1. REPORT NO.
EPA-450/3-85-020
3. RECIPIENT'S ACCESSION NO.
4, TITLE AND SUBTITLE
Kraft Pulp Mills—Background Information for
Promulgated Revisions to Standards
5, REPORT DATE
August 1985
6. PERFORMING ORGANIZATION CODE
7. AUTHORCS!
8. PERFORMING ORGANIZATION REPORT NO,
9. PERFORMING ORGANIZATION NAME AND ADDRESS
Office of Air Quality Planning and Standards
U.S. Environmental Protection Agency
Research Triangle Park, North Carolina 27711
10. PROGRAM ELEMENT NO.
11. CONTRACT/GRANT NO.
12. SPONSORING AGENCY NAME AND ADDRESS
DAA for Air Quality Planning and Standards
Office of Air and Radiation
U.S. Environmental Protection Agency
Research Triangle Park, North Carolina 27711
13. TYPE: OF REPORT AND PERIOD COVERED
14. SPONSORING AGENCY CODE
EPA/200/04
15. SUPPLEMENTARY NOTES
16. ABSTRACT
As a result of the 4-year review of New Source Performance. Standards (NSPS) for
Kraft Pulp Mills, the Agency proposed revisions to the NSPS, which were promulgated
on February 23, 1978, and requested public comments. This document summarizes the
comments which were received and presents the Agency's response to those comments.
17.
KEY WORDS AND DOCUMENT ANALYSIS
DESCRIPTORS
b.lDENTIFl£RS/OP£N EMDED TERMS
c. COSATI Field/Group
Air Pollution
Kraft Pulp Mills
Particulate Matter
Total Reduced Sulfur
Standards of Performance
Pollution Control
Air Pollution Control
13 B
18. DISTRIBUTION STATEMENT
Release Unlimited
19. SECURITY CLASS (This Report}
Unclassified
21. NO. OF PAGES
37
20. SECURITY CLASS (This page)
Unclassified ;'
22. PRICE
EPA Form 2220-1 (Rev. 4-77) PREVIOUS EDITION is OBSOLETE
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