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: BARTFive FactorAnalysis

- 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 ofour "subjectto" modeling for Best Available Retrofit Technology (BART) and requested that Ash Grove perform a BART analysis and submit it to EPA Region 8. OnJune 30, 2007, AshGrove submitted a BART analysisto EPA that was performed by Trinity Consultants. We would liketo thank you for your submittal and want to recognize the effortthat has gone into developing the BART analysis for Ash Grove. We would also like to recognize yourchoice ofselective non-catalytic reduction (SNCR) as BARTfor 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 completeourreview. Following are EPA Region 8'scomments. Withthe exception ofthe EPA Control Cost Manual, documents referenced in ourcomments have been attached for your convenience. In addition, we are providing a copy ofcomments onthe Ash Grove BART analysis submittedto EPA onNovember 9, 2007 from the USDA Forest ServiceNorthern Region. 

### S02 Emissions and Controls

• The analysis used 10 years as the basis for the remaining useful life ofthe scrubber, however the useful life ofthese control technologies is expectedto 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 CostManual. • The efficiency for the wet scrubberis estimated at 90% inthe analysis. Generally, wet scrubbers can achieve an efficiency greaterthan 90% ("EPA Air Pollution Control Cost Manual", Sixth ed., EPA-452-02-001, January 2002, Section 5.2, Chapter 1, page 1-3). Please provide the data or analysis used tojustifythe 90% efficiency forthe 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 sulfurcoke and a low sulfur coal. We ask that youprovide an analysis ofthe maximum sulfurreduction 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 ifa higher reduction in SOz canbe achieved. • Is the 2006 average 24-hour SOz emissionrate hourly equivalent (253.52 lb/hour) based on one year ofdata from the SOzlNOx analyzerthat was installed on the kiln exhaust? Please provide an average and a range for the sulfurdioxide 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 appearreasonable on a dollar perton reduced emissions basis, but the BARTGuidelines do specify that sources need to provide data supplied by a vendorto 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 scrubberruns 24 hrs/day for 365 days/year, (8,760 hrs/year), however, the cost effectiveness values are based on an operating yearof7,740 hrs/year. Boththe cost and cost effectiveness analysis should be based on the same number ofoperating hours. Ash Grove should revise the analysis so the operating hours used are consistent. NO

### x Emissions and Controls

• In section 5.2.4 you eliminate the option to use mid-kiln firing oftires. The reason provided is that youforesee a lack ofavailability oftires because the Ho1cim plant is pursuing apermit 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** ofsupply, there are otherfuels 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 AirInjection." IEEE2002). Ash Grove should provide an analysis for other fuels that could be used in mid-kiln firing. • With regard to the efficiency and NOxemissionreductions that can be achieved by SNCR, a recent article indicates that SNCR can reliably attain aNOx emission rate of800 mg/m3, and in most cases attain a rate of500 mg/m3 (See Scur, P. Cemex Ostzement, Redersdorf. Hoppe, Dr. Forchunginstitut der Zementindustrie, Dusseldorf. "The Present State ofNOx Abatement with the SNCRProcess." Cement International No. 2/2006, Volume 4., ISSN 1610-6199). Using dataprovided by Ash Grove, we have calculated the currentNOx 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. RequestforBestAvailable Retrofit Technology Information Pursuant to the RegionalHaze Rule. October 12,2006). Achieving an 800 mg/m3 concentration would be equivalent to a 60% reduction in NOx emissions fromjustthe SNCR. Installation ofthe lowNOx burner and SNCRis expected to provide an even greater reduction

.. Please analyze the SNCR and low NOx burner scenario with the best reduction 2achievable without limiting the analysis to a 35% reduction. 

### ParticulateMatter(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 onthe clinker cooler. Itis possible that BART for PM for these two units could include additional controls and/or increased performance ofthe existing technologies. We ask that Ash Grove submit the design parameter information for PM controls onthe kiln and clinker cooler and evaluatethe possibility ofadditional controls and increased performance ofthe existing equipment. 

### Overall Comments

• We wantto acknowledge the modeling work that was done by Ash Grove to reflect more current data and higher emissionrates 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 stacktest 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 submitthe 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 bothofthese options would offer substantial emissionsreductions at potentially reasonable costs (See Assessmentof NOx Emissions Reduction Strategiesfor CementKilns

- Ellis County

- FinalReport. Prepared by ERG, Inc. for Texas Commission on Environmental Quality. TECQ CntractNo. 582-04-65589, Work Order No. 05-06. July 14,2006and A Unique Approach. Menke, T., Jepsen, O.L., and Keefe, B.P. ReviewNo. 136. Reprint from IEEE-IAS/PSCA 2001 Cement industry Technical Conference May 2001 andpublished 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 onpage 1-1 the document states "thus itwas concludedthatthe contribution o/the non-kiln andclinker coolersources 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 ofthe petroleum coke is listed as approximately 4.5%. On page 4-9 in the text, the sulfur content ofthe 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 of Suitability of Selective Catalytic Reduction andSelective Non-Catalytic reduction for use in PortlandCementIndustry. Is this the same document? Ifso has it been published in apeerreviewedjournal?

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 90percentreduction was appliedto the 2006average... ' Are these statements accurate?

In orderto 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 ofthis 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. Ifyouhave any questions, please contact Laurel Dygowski at (303) 312-6144.

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## 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 submittedbyAsh Grove Cement.

• We concur with the analysis provided byEC/Rthat a greater level ofcontrol ofNOx emissions can be achieved using SNCR and a low NOx burnerthan what is quoted by Ash Grove. Ash Grove should redo its calculationsbased on thehighest potentiallevcl ofcontrol.

• The Forest Service would like to see more information pertaining to the actual level of PM\o control provided bythe existing control devices. The Forest Service is concerned about the high levels ofPM 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 Iareas, notjustGates ofthe Mountains. Thank you for the opportunity to provide comments onthis analysis. Sincerely,

# '~i0P'hLu- ttt/f}£&'L!i,;:A (THOMAS L. TIDWELL

Regional Forester

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