UNITED STATES ENVIRONMENTAL PROTECTION AGENCY
 

REGION 8
 

1595 Wynkoop Street 

DENVER, CO 80202-1129 

Phone 800-227-8917 

http://www.epa.gov/region08 

Ref: 8P-AR 

Joe Scheeler 

Ash Grove Cement Company 

100 Highway 518 

Clancy, MT 59634-9701 

Re: BART Five Factor Analysis - Ash Grove Cement, Montana City, Montana 

Dear Mr. Scheeler: 

On February 28, 2007, EPA Region 8 sent a letter to Ash Grove Cement Company (Ash 

Grove) that provided the results of our "subject to" modeling for Best Available Retrofit 

Technology (BART) and requested that Ash Grove perform a BART analysis and submit it to 

EPA Region 8. On June 30, 2007, Ash Grove submitted a BART analysis to EPA that was 

performed by Trinity Consultants. We would like to thank you for your submittal and want to 

recognize the effort that has gone into developing the BART analysis for Ash Grove. We would 

also like to recognize your choice of selective non-catalytic reduction (SNCR) as BART for 

NOx. 

We have completed our initial review ofthe June 30, 2007 submittal and have determined 

that there is additional information and analysis needed from Ash Grove in order for us to 

complete our review. Following are EPA Region 8's comments. With the exception of the EPA 

Control Cost Manual, documents referenced in our comments have been attached for your 

convenience. In addition, we are providing a copy of comments on the Ash Grove BART 

analysis submitted to EPA on November 9, 2007 from the USDA Forest Service Northern 

Region. 

S02 Emissions and Controls 

•	 The analysis used 10 years as the basis for the remaining useful life ofthe scrubber, however 

the useful life of these control technologies is expected to be 15 years based in information 

from the EPA Control Cost Manual ("EPA Air Pollution Control Cost Manual", Sixth ed., 

EPA-452-02-001, January 2002, Section 5.2, Chapter 1, page 1-28). Ash Grove needs to 

reanalyze the annualized costs for the scrubber using fifteen years as provided in the EPA 

Control Cost Manual. 

•	 The efficiency for the wet scrubber is estimated at 90% in the analysis. Generally, wet 

scrubbers can achieve an efficiency greater than 90% ("EPA Air Pollution Control Cost 

Manual", Sixth ed., EPA-452-02-00 1, January 2002, Section 5.2, Chapter 1, page 1-3). 

Please provide the data or analysis used to justify the 90% efficiency for the wet scrubber. 
•	 Calculations for fuel switching in the analysis are based on reducing the coke consumption 

relative to the coal consumption. Another option would be to look at the reductions that can 

be achieved using both a low sulfur coke and a low sulfur coal. We ask that you provide an 

analysis of the maximum sulfur reduction that can be achieved by using both a low sulfur 

coke and a low sulfur coal without limiting the analysis to a 50% reduction in SOz if a higher 

reduction in SOz can be achieved. 

•	 Is the 2006 average 24-hour SOz emission rate hourly equivalent (253.52 lb/hour) based on 

one year of data from the SOzlNOx analyzer that was installed on the kiln exhaust? Please 

provide an average and a range for the sulfur dioxide concentration in the kiln exhaust gas 

along with the exhaust gas flow rate. 

•	 The derived costs for fuel substitution and wet scrubbing that are provided appear reasonable 

on a dollar per ton reduced emissions basis, but the BART Guidelines do specify that sources 

need to provide data supplied by a vendor to estimate costs, or sources need to evaluate costs 

using techniques developed in the EPA Control Cost Manual or other referenced documents. 

Ash Grove needs to provide documentation that verifies the costs that were used for fuel 

switching and wet scrubbing. 

•	 The cost analysis assumes the wet scrubber runs 24 hrs/day for 365 days/year, (8,760 

hrs/year), however, the cost effectiveness values are based on an operating year of7,740 

hrs/year. Both the cost and cost effectiveness analysis should be based on the same number 

of operating hours. Ash Grove should revise the analysis so the operating hours used are 

consistent. 

NOx Emissions and Controls 

•	 In section 5.2.4 you eliminate the option to use mid-kiln firing of tires. The reason provided 

is that you foresee a lack of availability of tires because the Ho1cim plant is pursuing a permit 

to burn tires. While a permit for Holcim to burn tires at its plant in Three Forks may make 

burning tires cost prohibitive for Ash Grove because of l~ck of supply, there are other fuels 

that potentially could be used in mid kiln firing to achieve reductions in the 45% range (See 

Hansen, Eric R. Technical Consultant, Cadence Environmental Energy Inc. "Stated 

Combustion for NOx Reduction Using High Pressure Air Injection." IEEE2002). Ash Grove 

should provide an analysis for other fuels that could be used in mid-kiln firing. 

•	 With regard to the efficiency and NOx emission reductions that can be achieved by SNCR, a 

recent article indicates that SNCR can reliably attain a NOx emission rate of 800 mg/m3, and 

in most cases attain a rate of 500 mg/m3 (See Scur, P. Cemex Ostzement, Redersdorf. 

Hoppe, Dr. Forchunginstitut der Zementindustrie, Dusseldorf. "The Present State of NOx 

Abatement with the SNCR Process." Cement International No. 2/2006, Volume 4., ISSN 

1610-6199). Using data provided by Ash Grove, we have calculated the current NOx 

emission concentration as approximately 1,950 mg/m3 (See Letter from Joseph L. Scheeler 

Environmental, Health and Safety Manager, Ash Grove Cement Company to Laurel 

Dygowski, U.S. EPA Region 8. Requestfor Best Available Retrofit Technology Information 

Pursuant to the Regional Haze Rule. October 12,2006). Achieving an 800 mg/m3 

concentration would be equivalent to a 60% reduction in NOx emissions from just the SNCR. 

Installation of the low NOx burner and SNCR is expected to provide an even greater 

reduction.. Please analyze the SNCR and low NOx burner scenario with the best reduction 

2
 
achievable without limiting the analysis to a 35% reduction. 

Particulate Matter (PM) Emissions and Controls 

•	 Ash Grove did not provide any design parameters for the existing PM control technologies 

for the ESP on the kiln and the baghouse on the clinker cooler. It is possible that BART for 

PM for these two units could include additional controls and/or increased performance of the 

existing technologies. We ask that Ash Grove submit the design parameter information for 

PM controls on the kiln and clinker cooler and evaluate the possibility of additional controls 

and increased performance of the existing equipment. 

Overall Comments 

•	 We want to acknowledge the modeling work that was done by Ash Grove to reflect more 

current data and higher emission rates from the CEM rather than the stack test. The results 

from the modeling that Ash Grove performed using the higher emission rates from the CEM 

rather than the stack test are provided for Gates ofthe Mountains but not other Class I areas. 

In order for us to fully analyze the impacts from Ash Grove, we request that you submit the 

modeling results for other Class I areas, specifically Scapegoat and Bob Marshall. 

•	 Your analysis did not include a conversion from a wet kiln to a semi-dry or dry kiln. Several 

documents in the literature indicate that both of these options would offer substantial 

emissions reductions at potentially reasonable costs (See Assessment ofNOx Emissions 

Reduction Strategies for Cement Kilns - Ellis County - Final Report. Prepared by ERG, Inc. 

for Texas Commission on Environmental Quality. TECQ Cntract No. 582-04-65589, Work 

Order No. 05-06. July 14,2006 and A Unique Approach. Menke, T., Jepsen, O.L., and 

Keefe, B.P. Review No. 136. Reprint from IEEE-IAS/PSCA 2001 Cement industry 

Technical Conference May 2001 and published in International Cement Review, July 2001). 

Please include an analysis that addresses a conversion from a wet kiln to a semi-dry or dry 

kiln. 

There are also several locations in the document that may have typographical errors. 

•	 In the first footnote on page 1-1 the document states "thus it was concluded that the 

contribution o/the non-kiln and clinker cooler sources to visibility impairment is 

negligible." This should be revised to remove the reference to the clinker cooler, as only 

the non-kiln sources have a negligible contribution to impairment. 

•	 On page 4-2 the sulfur content of the petroleum coke is listed as approximately 4.5%. On 

page 4-9 in the text, the sulfur content of the petroleum coke is listed as 3%. Please 

revise the analysis so that the number used for the sulfur content is consistent. 

•	 Reference 13 on page 5-10 is incomplete. We have a document from Schreiber, Russell 

and Evers titled Evaluation ofSuitability ofSelective Catalytic Reduction and Selective 

Non-Catalytic reduction for use in Portland Cement Industry. Is this the same 

document? If so has it been published in a peer reviewed journal? 

3 
•	 Table 5-3 lists the LNB and SNCR as achieving approximately 35% control. Is this 

intended to be 50%? All three footnotes to table 5-3 state 'The 90 percent reduction was 

applied to the 2006 average ... ' Are these statements accurate? 

In order to move forward with the BART process, we ask that you submit the requested 

information and analysis to our office within thirty days from the date of this letter. 

Once again, we would like to thank you for submitting the BART analysis and 

acknowledge the work that has gone into preparing this analysis. If you have any questions, 

please contact Laurel Dygowski at (303) 312-6144. 

4 *

Printed on Recycled Paper 
USDA United States Forest Region One Northern Region 

Department of Service 200 East Broadway 

Agriclilture Missoula, MT 59802 

File Code: 2580 

Date: NOV 9 2'00? 

Laurel Dygowski 

Regional Haze Coordinator 

Air Quality Planning and Management Unit 

US EPA - Region 8 

1595 Wynkoop Street 

Denver, CO 80202-1129 

Dear Ms. Dygowski: 

The USDA Forest Service Northern Region is pleased to provide the following comments in 

regards to the BART Analysis submitted by Ash Grove Cement. 

•	 We concur with the analysis provided by EC/R that a greater level of control of NOx 

emissions can be achieved using SNCR and a low NOx burner than what is quoted by 

Ash Grove. Ash Grove should redo its calculations based on the highest potentiallevcl 

of control. 

•	 The Forest Service would like to see more information pertaining to the actual level of 

PM\o control provided by the existing control devices. The Forest Service is concerned 

about the high levels of PM 10 emissions even with the existing controls in place. 

•	 When assessing deciview improvements or costs per deciview for improvements, Ash 

Grove should consider all Class I areas, not just Gates ofthe Mountains. 

Thank you for the opportunity to provide comments on this analysis. 

Sincerely, 

'~i0P'hLu- tt t/f}£&'L!i,;:A 

(THOMAS L. TIDWELL 

Regional Forester 

Caring for the Land and Serving People	 rrinted on Recycled Paper