UNITED STATES ENVIRONMENTAL PROTECTION AGENCY 

REGION 5 

Vincent Hellwig, Chief 

AIR AND RADIATION DIVISION 

77 WEST JACKSON BOULEVARD 

CHICAGO, IL 60604-3590 

MAY 2 4 2012 

Air Quality Control Division --.. -------

Michigan Department of Environmental Quality 

P.O. Box 30260 

Lansing, Michigan 48909 

Dear Mr. Hellwig: 

REPLY TO THE ATTENTION OF: 

Thank you for Michigan's submittal ofa regional haze plan on November 5, 2010. Based 

on our review ofthis submittal, we believe that the plan does not require best available 

retrofit technology (BART) on several sources that must install and operate such controL 

Whereas the plan provides only for existing controls at these sources, these sources have 

significant impacts on the Seney Wildlife Refuge and other Class I areas, and we believe 

that more effective controls may be implemented at reasonable cost. In particular, we 

believe that the following controls warrant being mandated by the Michigan plan: 

NewPage Paper - For nitrogen oxides (NOx), low NOx burners for control of emissions 

from Boiler 8 and Boiler 9 

St. Mary's Cement - Selective noncataIytic reduction for control of NO x emissions. In 

addition, a limit for sulfur dioxide emissions reflecting current emission levels, thereby 

requiring either continuation of current use oflow sulfur raw materials, or, if higher sulfur 

raw materials must be used, emission control equipment to maintain low emissions. 

Tilden Mines - Low NOx burners, at a minimum, will likely be required, along with 

continuous NOx emission monitoring. Requirements for sulfur dioxide controls and 

emissions monitoring will be further evaluated after reviewing the company's response to 

our section 114 information request. 

The attachment provides further details on each of these facilities and the information we 

considered in reaching these conclusions. In conjunction with this attachment are 

spreadsheets showing revised estimates of costs for the above control equipment for 

NewPage Paper and St. Mary's Cement as well as a spreadsheet analyzing emissions data 

from St. Mary's Cement. 

We have been working with your staff on these issues, including sharing a draft of this 

letter and attachments. We appreciate your working with the affected companies to solicit 
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their comments on the draft materials. As is particularly evident for NewPage Paper, we 

have given careful consideration to their comments. 

We have negotiated a consent decree with the National Parks Conservation Association to 

specify deadlines for action on Michigan's and other states' regional haze plan submittals. 

This consent decree will require prompt action to satisfy regional haze requirements, either 

through approval of state plans or promulgation of federal plans. In particular, we are to 

sign proposed action by July 13,2012, and we are to sign final action by November 15, 

2012. We are under the same timetable for acting on BART limits for taconite plants in 

Minnesota, and we plan to act on Tilden Mines and on the Minnesota taconite plants in a 

coordinated marmer that assures consistency in the regulation of these plants in the two 

states. 

I look forward to continuing to work with you to resolve our concerns, to assure that 

emission limits necessary to satisfy the requirement for BART are in place. Please contact 

me or John Surnmerhays at (312) 886-6067 if you have any questions. 

Sincerely, 

Douglas Aburano, Chief 

AttaimnentPlanning and Maintenance Section 

Attachments 
Best Available Retrofit Technology (BART) 

For NewPage Paper 

Reevaluation of costs for controlling nitrogen oxides (NOx) emissions indicate that low NOx 

burners would provide cost-effective control of emissions at Boiler 8 and Boiler 9 of the 

NewPage Paper company facility in Escanaba, Michigan (NewPage). Spreadsheets showing a 

revised set of cost estimates are attached. Many of the elements ofthis spreadsheet are taken 

directly from estimates provided by the company's consultant. The following elements reflect 

the following revisions: 

- Installation costs are estimated to be 50 percent of purchased equipment costs. While low NOx 

burners are not directly addressed in the EPA Air Pollution Control Cost Manual (EPA CCM, 

available at http://www.epa.gov/ttncatcllproducts.html#cccinfo).this estimate is more consistent 

with cost factors given in the EPA CCM, adjusted for the fact (acknowledged by NewPage) that 

installing low NOx burners is simpler than installing more complicated control such as selective 

catalytic reduction. Retrofit installations may cost somewhat more than new installations, but 

the company's estimates, that installation costs would be 114 percent and 184 percent of 

purchased equipment costs for boilers 8 and 9 respectively, is far higher than the range of retrofit 

installation costs indicated in the EPA CCM. The company has not provided adequate 

justification for its assumption of such high installation costs. 

- The company's estimate for the costs of a low NOx burner for Boiler 9 assumes that the boiler 

will become fired with natural gas. EPA is estimating costs based on an assumption that a 

substantial fraction of the fuel fired in the boiler will continue to be wood waste. Low N Ox 

burners have been successfully demonstrated for use with a variety of fuels including wood 

waste, though EPA is estimating that engineering costs for designing this installation will be 20 

percent rather than 10 percent of purchase costs. EPA finds that firing this boiler with natural 

gas would also be a cost effective means of reducing emissions, except that EPA believes that 

the company misestimates the cost effectiveness of this measure. The company estimates that 

conversion to natural gas would reduce NOx emissions to 33.9 tons per year, and that use of a 

low NOx burner would reduce NOx emissions by a further 13.6 tons per year, to 20.3 tons per 

year. The company's cost effectiveness estimate credits the measure only for the 13.6 tons per 

year, as if the boiler had already been switched to fire only natural gas, but in fact this strategy 

should be credited as achieving the additional emission reductions inherent in the switch to firing 

only natural gas. That is, the cost effectiveness of this measure should be estimated based on 

credit for the full reduction from baseline NOx emissions of 296.6 tons per year. 

- Consistent with recommendations in the EPA CCM for more complicated control equipment, 

the attached spreadsheets assume that low NOx burners require minimal oversight to operate, 

such that no additional labor should be budgeted for their operation. 

- The EPA CCM recommends annualizing costs by assuming substantially longer equipment life 

and lower interest rates than were assumed by the company. The attached spreadsheet 

annualizes investment costs by assuming a IS-year equipment life and 7 percent interest. 
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- Installation oflow NOx burners will allow NewPage Paper to forgo operating flue gas 

recirculation (FGR), which the company currently operates for 5 months per year. Therefore, 

use of low NOx burners will provide a savings of the costs that would otherwise be expended on 

FGR. To estimate these savings, EPA used the company's annual FGR operating cost estimates, 

adjusted to reflect that the savings may be considered to be 5/12 of the costs of full year 

operation ofFGR. Since the company estimated the same annual operating cost ofFGR for both 

boiler 8 and boiler 9, the attached spreadsheet applies the same estimate of the savings from not 

operating FGR for both boilers, namely $36,925. 

Based on these revised estimates, we estimate that low NOx burners could control NOx 

emissions at these boilers at a cost-effectiveness of$430 per ton and $250 per ton at boilers 8 

and 9, respectively. Even without crediting the savings of not operating FGR, low NOx burners 

would be estimated to have a cost effectiveness of $1080 per ton and $560 per ton at boilers 8 

and 9, respectively. The significant impact of these boilers on visibility, and thus the substantial 

benefit of controlling emissions from these boilers, indicates that low NOx burners for these 

boilers should be considered to be BART for this facility. 
Best Available Retrofit Technology (BART) 

For St. Mary's Cement 

A reevaluation of available evidence indicates that selective noncatalytic reduction (SNCR) 

would provide cost-effective control of nitrogen oxides (NOx) emissions at the St. Mary's 

Cement facility in Charlevoix, Michigan (SMC). The following discussion addresses the issue 

of material buildup, cost estimates, and evidence regarding an emission limit that would be 

appropriate with this control. 

In addition, while evidence submitted by Michigan appears to support defining BART for sulfur 

dioxide (S02) under current conditions as no further control, the company anticipates possible 

use of higher sulfur raw materials which would make emissions control more cost effective. 

Therefore, EPA believes that BART must be defined with a limit set at approximately current 

emissions. Such a limit would also prohibit switching to higher sulfur fuels without the 

installation of additional controls. The following discussion derives such a limit. 

Material Buildup Issue 

SMC's BART analysis asserts that introduction of wet urea as part of an SNCR system would 

seriously exacerbate the facility's problems with material buildup, necessitating lost production 

during down-time for manual removal of the buildup to restore proper airflow. SNCR has been 

successfully demonstrated at many cement plants across the country, which suggests that 

solutions to this problem are readily available. 

One alternative for addressing material buildup issues involves redesign of the facility's 

preheater/precalciner system. Indeed, SMC applied for and was issued a permit, #700-77L, for a 

redesign that, by replacing the existing flash precalciner with a low NOx in-line calciner, will 

provide improved airflow and less potential for material buildup problems near the point of urea 

injection. Although the company chose not to construct the modification authorized in this 

permit, since the company determined that the price of cement did not warrant the expense of 

this project, the point here is that options are available for reducing the potential for material 

buildup by adjusting the design of the preheater/precalciner system. 

SMC notes a second option for addressing material buildup, by installing additional "air 

cannons" to provide periodic pneumatic cleaning at strategic locations. Other options may 

include use of other cleaning approaches and use of higher concentrations of urea (i.e., urea with 

less water). EPA will not dictate a particular approach, but the important point here is that this 

problem has been solved elsewhere, and EPA believes that either SMC or a suitable consultant 

can solve this problem here. 

For purposes of evaluating the cost-effectiveness of SNCR at the SMC, EPA assumed some 

costs would be incurred to mitigate material buildup. While a full engineering analysis would 

provide more precise cost estimates, the attached spreadsheet relies on two assumptions 

regarding these costs: I) that capital costs to address material buildup issues are as much as half 

the cost of the SNCR equipment costs, and 2) maintenance costs are twice the normal SNCR 
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maintenance costs. 

Cost Effectiveness ofSNCR at SMC 

A spreadsheet is attached which shows a revised set of estimates of cost and cost-effectiveness 

for the installation ofSNCR at this facility. Many of the elements of this spreadsheet are taken 

directly from estimates provided by the company's consultant. For example, the estimates of 

capital costs are unchanged from those provided by the company's consultant. The following 

elements reflect the following revisions: 

- Electricity: The "cooler season," for which 100 kilowatts are estimated to be needed for heating 

urea, is assumed to be 4000 hours. 

- Clean-out: As discussed above, costs are added to address material buildup. The attached 

spreadsheet assumes no costs for lost revenue due to clean out of cementic build-up, and 

conversely assumes no gain in revenue from addressing material buildup issues that exist 

currently. However, the attached spreadsheet assumes that addressing material buildup 

sufficiently to accommodate use of SNCR while having no more material buildup than presently 

occurs will impose costs equal to one half of the cost of the SNCR equipment and will require 

twice the maintenance that is normally associated with SNCR. 

- Capital recovery: More consistently with the range recommended in the EPA CCM, the 

equipment life is assumed to be 15 years. 

- Pollutant Removed: The Environ report included in the SMC BART evaluation notes that 

SNCR achieves between 10 and 50 percent NOx control efficiency. While the current SNCR 

may have problems that limit its effectiveness to eliminating only 10 percent of NO x emissions, 

BART must reflect consideration of control options which significantly improve SMC's NOx 

control efficiency. The BART determination cannot plausibly be based on an evaluation that 

finds that spending substantial capital costs would achieve no improvement in NOx control as 

compared to existing equipment. Control efficiency is discussed further below. The attached 

spreadsheet assumes that the upgraded control equipment will achieve 50 percent NOx control. 

The continuous emission monitoring data provided by SMC for 2006 to 2008 indicates that 

average NOx emissions for those three years are 2518 tons per year. Thus, SNCR is assumed to 

reduce NOx emissions by 1259 tons per year. 

- The attached spreadsheet uses a revised estimate of reagent costs. Based on results at St. 

Mary's Cement's facility in Dixon, Illinois, the attached spreadsheet assumes that injection of 

urea in the quantity of 57 percent of the molar equivalent of the quantity of uncontrolled NOx 

will suffice to achieve 46 percent reduction of NO x emissions, suggesting that injecting urea in a 

molar ratio to uncontrolled NOx of 62 percent would achieve 50 percent NOx reduction. The 

cost per ton of urea (before dilution) is assumed to be $450 per ton. 

- The revised spreadsheet estimates that SNCR would reduce NOx emissions at SMC's facility at 

a cost of $983 per ton. Since this control would achieve substantial improvement in visibility at 

the Seney Wildlife Refuge, this evidence suggests that BART at this facility would include full 
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year operation of upgraded SNCR. 

- The evaluation of BART for S02 at the SMC facility is premised on the sulfur contents of 

materials in the future remaining similar to current sulfur contents. The submittal raises the 

possibility that future raw material may contain significantly more sulfur. Such an increase 

would make S02 control equipment more cost effective, since equipment at similar cost would 

control more S02 emissions. While S02 control equipment appears under current circumstances 

to be marginally more expensive than would be considered cost-effective, it appears likely that 

S02 control equipment would be cost-effective if the sulfur content of the raw materials 

increased. 

Therefore, this evidence suggests that current S02 emissions represent BART for this facility. 

SMC could achieve current S02 emissions either by continuing to use comparatively low sulfur 

raw materials or by operating S02 control equipment to accommodate use of higher sulfur raw 

materials. Under Michigan's submittal, SMC is allowed much greater S02 emissions than are 

currently emitted (as requested by SMC to accommodate higher sulfur raw materials). An 

emission limit reflecting current S02 emissions is necessary to assure that BART is in place for 

S02 for SMC. 

Appropriate Emission Limits 

Several types of information are available to support a determination of the emission limit that 

SMC can be expected to meet with proper installation and use of SNCR. 

According to continuous emission monitoring data reported by SMC, the average NOx emission 

rate for 2006 to 2008 is 4.52 pounds per ton of clinker. This is quite similar to the representative 

emission factors for similar Portland cement manufacturing facilities given in the EPA emission 

factor guidance document known as AP-42, which is 4.2 pounds of NO x per ton of clinker for 

preheaterlprecalciner kilns and 4.8 pounds of NO x per ton of clinker for preheater process kilns. 

The SMC data for 2006 to 2008 also indicate that the maximum 30-day average NOx emission 

rate was 6.50 pounds per ton, and the 95th percentile value among 30-day average NOx emission 

rates was 5.78 pounds per ton of clinker. Conversely, the 5

th percentile value among 30-day 

average NOx emission rates was 3.33 pounds per ton of clinker. While SMC installed an 

indirect firing system in 2005/2006 that significantly reduced NOx emissions, the emission rates 

in 2006 are sufficiently similar to emission rates in 2007 and 2008 that use of a full 3-year 

baseline appears to provide a more robust representation of current emissions than use of data for 

a shorter period. 

EPA has conducted a recent review of options for controlling emissions for Portland cement 

plants, in developing new source performance standards for these facilities. EPA published final 

new source performance standards on September 9, 2010, at 75 FR 54970. Unlike prior new 

source performance standards for cement kilns, which had been set to limit the pounds of 

emissions per ton of feed material, the new standards set limits per ton of clinker produced. 

These standards included a new standard for NOx emissions, set at 1.5 pounds per ton of clinker 

on a 30-day rolling average basis. 
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Other reviews similar to EPA's review for its new source performance standards have also found 

SNCR to be an effective means of controlling NOx emissions from existing cement kilns. EPA 

made similar findings in an earlier review, given in a report published in 2000 entitled, "NOx 

Control Technologies in the Cement Industry: Final Report" (EPA-457/R-00-002, September 

2000, available at http://www.epa.gov/ttnnaags/ozone/ctg act/200009 nox epa457 r-OO002 cement industry.pdf). Although application of NO x control technology was relatively rare 

in the United States at the time (i.e., before the NOx SIP Call required control), EPA found 

SNCR to be an effective means of reducing NOx emissions, commonly achieving 50 percent or 

more reduction. Regional planning organizations evaluating options for BART also made 

similar findings. (See, for example, "Identification and Evaluation of Candidate Control 

Measures-Phase II Final Report", June 2006, available at 

http://www.ladco.org/reports/control/final reports/identification and evaluation of candidate c 

ontrol measures ii june 2006.pdf.) 

Similarly, according to the RACT/BACT/LAER Clearinghouse, recent permits for new Portland 

cement kilns have set BACT limits of 1.50 pounds of NO x per ton of clinker (issued on June 27, 

2007 by Florida to Cemex) and 1.95 pounds of NO x per ton of clinker (on January 27,2010 by 

Georgia to Cemex and on June 19,2007 by Georgia to Houston American Cement). These 

limits were also set on a 30-day rolling average basis. 

Extensive testing of SNCR at St. Mary's Cement's facility in Dixon, Illinois, appears to provide 

the most germane information regarding the potential effectiveness of SNCR at St. Mary's 

Cement's facility in Charlevoix, Michigan. The key portions of the report on this testing are 

provided as an additional attachment. At the Dixon facility, short term tests (generally between 

5 and 10 minutes per test) were conducted to test the emission impact of different rates of urea 

injection, as well as to assess the most effective and appropriate location in the ductwork to 

inject urea. These tests are best considered in relation to the stoichiometric ratio (i.e., the molar 

ratio) of the ammonia equivalent of the urea versus the pre-controlled quantity ofNOx. These 

tests used a range from 0.28 to 1.79 moles of ammonia-equivalent per mole of pre-controlled 

NOx. 

These tests showed SNCR to be highly effective. Even the lowest urea injection rates (with an 

average molar ratio of 0.30) achieved an average of29 percent reduction of NO x emissions. A 

set of tests with a molar ratio around 0.6 achieved an average 51 percent reduction in NOx 

emissions. Tests using an average molar ratio of 1.2 achieved an average of 83 percent reduction 

in NOx emissions. 

Additional longer term tests, lasting 1 to 3 days each, were conducted at the Dixon facility to 

assess whether the NOx reductions demonstrated in the short term tests were sustainable for 

longer periods. These tests used a quantity of urea injection equivalent to a stoichiometric ratio 

with pre-control NOx emissions of approximately 0.6. The results were quite similar to the 

results of the short term tests, achieving a 46 percent reduction in NOx emissions. 

This information supports setting a limit on NOx emissions that requires an average 50 percent 

control efficiency. Average emissions at SMC are 4.52 pounds per ton of clinker, and so 50 
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percent control efficiency would achieve an emission rate of 2.26 pounds per ton of clinker, 

which may be expressed in two significant figures as 2.3 pounds per ton of clinker. Achieving 

this emission rate would require slightly under 60 percent reduction from the 95th percentile 

emission rate, while achieving this emission rate would require only about 31 percent reduction 

from the 5

th percentile emission rate. The available evidence indicates that achievement of 60 

percent control of NO x emissions at SMC is fully feasible, particularly since a limit of 2.3 

pounds per ton would only occasionally require this level of control. Therefore, a limit of 2.3 

pounds per ton of clinker, requiring an average control efficiency of 50 percent, appears to be a 

fully achievable emission rate even under conditions of relatively higher uncontrolled NOx 

emission rates. Thus, this information indicates that the appropriate limit to mandate BART for 

NOx at SMC is a limit of2.3 pounds of NO x per ton of clinker, expressed as a 30-day rolling 

average. 

The purpose of a limit on S02 emissions at SMC is not to require emission controls to achieve 

lower emissions; instead, the purpose is to assure that emissions do not increase significantly. 

Therefore, the appropriate starting point for determining a limit is maximum current emissions. 

The 95th percentile among 30-day average S02 emission rates in 2006 to 2008 at SMC was 6.81 

pounds per ton of clinker, and the maximum 30-day average S02 emission rate was 7.19 pounds 

per ton of clinker. Since the average S02 emission rate from 2006 to 2008 is 3.02 pounds per ton 

of clinker, and mosUO-day average S02 emission rates during 2006 to 2008 are well below 7.19 

pounds per ton of clinker, only a 5 percent compliance margin appears warranted to 

accommodate current operations, including current sulfur contents of raw materials and fuel. 

This indicates that an appropriate limit to require no additional control under current conditions 

but to require that emissions not increase significantly above current levels would be a limit of 

7.5 pounds of S02 per ton of clinker on a 30-day average basis. 
Best Available Retrofit Technology (BART) 

For Tilden Mine 

We have sent out a request for information under Clean Air Act section 114 to the Tilden Mining 

Company on April 20, 2012. We will determine BART for Tilden's indurating furnace(s) after 

reviewing this information. However, available evidence indicates that low NOx burners are a 

cost-effective means of controlling NOx from indurating furnaces at taconite plants. Michigan's 

SIP does not require such control, and Michigan'S SIP does not provide for adequate monitoring 

for judging whether emissions are being appropriately controlled. 

Also attached is a letter that EPA sent to Minnesota describing evidence from work by U.S. Steel 

at its Milmesota taconite facilities that low NOx burners are a feasible and effective option for 

reducing NOx emissions. In order to obtain the information necessary to set appropriate NOx 

emissions limits, we are requesting pertinent information from taconite plants in Minnesota, to 

supplement information we have already requested from Tilden Mine. 

We further believe that the taconite facilities in Minnesota and Michigan should install and 

operate systems that provide for continuous monitoring of NO x emissions in accordance with 

Performance Specification 2 in Appendix B of 40 CFR 60. This monitoring will serve several 

purposes: I) it will help identify the operating conditions in which higher and lower NOx 

emissions occur, 2) as the companies conduct trials of burner designs and related combustion 

improvements, it will provide needed feedback on which approaches are most effective, and 3) it 

will help ensure the continuous, effective control of NO x emissions. 

In addition, the need for S02 controls and continuous monitoring of S02 emissions will be 

evaluated after reviewing the requested information from Tilden.