1400 11 TH AVENUE· HELENA, MT 59601 • 406-442-5768

# ~BISON FAX: 406-449-6653 • E-MAIL blson@blson-eng.com • www.bison-eng.com 

## ENGINEERING, INC. January 25, 2008

# k~cYsj1~:!!l1­ Subiectto

# Confidentiality Cialni**,~** Callie Videtich Air Quality Planning and Management Unit US EPA
- Region 8 1595Wynkoop Street Denver, CO 80202-1129 Dear Ms. Videtich: 

### RE: Holcim BART Analysis - Response to EPA Comments Holcim has received your letter dated November 26, 2007, requesting more information. On behalf of Holcim US, Inc. (Holcim), Bison Engineering, Inc. (Bison) is pleased to submit responses to your questions. We have copied EPA's comments from your letter (numbered and marked by a black dot and small type), and furnished Holcim's responses in larger type. The responses are contained in Attachment A to this letter. A revised wet S02 scrubber cost analysis discussed in the comment responses is contained in Attachment B. A cost analysis for S02 control is contained in attachment C. 

### Please note Holcim considers the data contained in Attachment Band Attachment C CONFIDENTIAL and requests that EPA not distribute or publish these attachments. Please let us know ifyou have any questions on our responses. I can be reached at 406-442-5768, or Eric Ervin can be reached at 406-285-3985.



# ib'l Hal obbins 

## U President
cc: Eric Ervin
- Holcim Attachments

An Employee Ovvned Company

## Attachment A

EPA Comment#1 S02Emissions and Controls

• The analysis used 10years as the basis for the remaininguseful life ofthe scrubber, however the useful life ofthese controltechnologies is expectedto be 15 years basedon information from the EPA Control CostManual ("EPAAirPollutionControl CostManual", Sixthed., EPA-452-02-001, January 2002, Section 5.2, Chapter 2, page 2-51). Holcimneedsto reanalyze the annualized costs forthe scrubberusing fifteen years as providedin the EPA' ControlCostManual. '. 

### Holcim Response Holcim understands that the useful life expectancy of a wet venturi scrubber is up to 15 years; however, Holcim still believes a 10-year basis for BACT and BART analysis is standard and typical. This is based on financial concerns (Le., duration of financing rather than equipment life expectancy). To be complete, Holcim has analyzed the annualized cost for 15 years. These calculations include a revised cost estimate for the wet venturi scrubber as explained in comment #3. As you can see from the equations below, the annualized cost changes from $5.3 million/yr on a 10-year basis to $5.0 million/yr on a 15-year basis. This change is not large enough to substantially affect the results of Holcim's BART analysis as to whether the control device is economically feasible on a $/ton or a $/deciview basis.

. i(l

### + i)"



### -- Capital Recovery Factor (CRF) Formula:---'-----'­ (1 

### +i)" -1 7%(1 

### +7%)10

.



### -- CRF for 10 yrs @ 

### 7%: 10 = 0.142 

### (Annualized cost

# =$5,334,982/yr) (1 

### +7%) -1

. 7%(1 

### +7%)15

.



### -- CRF for 15 yrs @ 

### 7%: 15 

### =0.110 

### (Annualized cost

# =$5,029,378/yr) (1 

### +7%) -1 $5,334,982 = $19,847,4041deciview & $5,334,982 = $10,342Iton 0.269deciviewb. 516tonb. $5,029,378 = $18,710,4821deciview 

### & $5,029,378 = $9,750Iton 0.269deciviewb. 516tonb.
EPA Comment#2

• In section4.3.2, Holcim eliminates fuel substitutionas a means for reducing S<hreferencing a statement

### intheBARTGuidelineswhichreads: "Pollutionprevention: useofinherently lower-emittingprocesseslpractices, includingthe useofcontroltechniques (e.g.low-NOX burners) andworkpracticesthatpreventemissions andresUlt inlower "productionspecific"

. emissions (notethatitisnotourintenttodirect Statesto switchfuel forms, e.g. from coal to gas)" (see70 FR39164,July 6, 2005). EPAdidnotintendthisto meanthat sources should

Attachment A Page 1notbe looking atpotentially switchingto a lower sulfur contentcoal (orcoke) ifthe source is already usingcoal (orcoke)for fuel. The languageis meantfor situations where a facility**~'ould** be looking at switchingfrom onetype offuel to another, suchas coal to natural gas. Fuel substitution to lowerthe fuel sulfurcontentcanbe a very costeffective means for reducing S02 emissions and should be analyzed. 

### Holcim Response To start, Holcim believes that the design ofthe current kiln, a long, wet kiln with a strong alkali and lime atmosphere is, by itself, an ideal wet S02 scrubber. Holcim calculates that the kiln is approximately 95 to 99+% effective in removing S02 from the kiln exhaust gas. This results in little to no sulfur left in the exhaust gas stream. Historical data confirms this. For example, the last reference method stack testfor S02, performed in September of 2007, showed an S02 emission rate of 0.06 Ibs/hour. In addition, the average S02 emission rate for calendar year 2007 was 13.1 Ibs/hr (based on CEM data). This information confirms that the current plant configuration lends itself as an effective S02 scrubbing system. The data indicates that switching to a lower-sulfur fuel will, in reality, have little measurable effect on S02 emissions. In addition, these lower sulfur emissions lead to a negligible improvement in visibility at nearby Class I areas since modeled improvements are based on extreme situations rather than the norm. Nonetheless, to answer the comment, a fuel switching analysis has been performed to determine the visibility improvement and associated costs with several different fuel blend scenarios. Keep in mind, this whole analysis is based on the emission limit of 124 Ibs/hr on a 30-day rolling basis, and actual emissions are closer to zero. Thus, the visibility improvements and cost calculations are grossly inflated. Currently, Holcim's goal is to operate the kiln using a 40% petroleum coke / 60% coal blend on a Btu basis. Holcim's current coke supply has an average sulfur content of approximately 5.3%, with a heat value of approximately 14,000 Btu/lb on an as-received basis. Holcim's current coal supply has an average sulfur content of approximately 0.8%, with a heat value of approximately 9,350 Btu/lb on an as-received basis. The coal Holcim uses is a low sulfur, high Btu content western coal. Holcim is not aware of a coal supply with a significantly lower sulfur content. For purposes of a fuel switching analysis, it is assumed that this coal will be used exclusively. The petroleum coke Holcim uses has a relatively high sulfur content, but is considered typical for a coke used as a fuel. There are other grades of coke that have similar Btu values, but have lower sulfur contents. Holcim has identified two other grades of coke that are available, at higher costs. For the purposes of this fuel switching analysis, Holcim has briefly followed the same BART five-step process as outlined in the Holcim BART report.

Attachment A Page 2

### Step 1 - Identify S02 Reducing Fuel Blends For purposes of this analysis, Holcim has identified the current desired operating coal/coke blend as the baseline case. Four other coal/coke blends, as identified below, were analyzed for costs and visibility impacts. The scenarios are as follows (all blends are on a Btu basis):

• Baseline: 40% coke (5.3% S) / 60% coal (0.8% S) • Option 1: 25% coke (5.3% S) / 75% coal (0.8% S) • Option 2: 25% coke (3.5% S) / 75% coal (0.8% S) • Option 3: 25% coke (2.9% S) / 75% coal (0.8% S) • Option 4: 0% coke /100% coal (0.8% S) 

### Step 

### 2 - Eliminate Technically Infeasible Fuel Blend Options All of the above listed fuel blends can be easily implemented; therefore none is eliminated on the basis of being technically infeasible. 

### Step 3 - Evaluate Control Effectiveness of Remaining Control Options Table 1 below lists the estimated 

### S02 control efficiencies ofthe fuel blend options. 

### Step 4 - Evaluate Impacts and Document Results Fuel Blending Economic Impacts Holcim has calculated the cost-effectiveness for employing each of the fuel blend options for 

### S02 control, with the results presented in Table 1 below. Holcim has utilized vendor information on coke availability and cost on a dollar per ton basis in these calculations. To calculate the cost-effectiveness of a fuel blend in dollars per ton ($/ton), the following equation is used: 

### Cost-effectiveness ($/ton) = [(total capital investment 

### x capital recovery factor {CRF}) + Direct Annual Cost + Indirect Annual Cost]/(tons 

### S02controlled) In this case, since Holcim already blends fuels, there is no capital investment or indirect annual cost, the only cost is the direct added cost of lower sulfur fuels. Fuel Blending Environmental Impacts Holcim is not aware ofany adverse environmental impacts of using any ofthe fuel blend options.

Attachment A Page 3

### Fuel Blending Energy Impacts Holcim is not aware of any adverse energy impacts of using any of the fuel blend options. Step 5 - Evaluate Visibility Impacts Holcim used the CALPUFF model to predict visibility impacts of the identified fuel blending 802control options, using the 98th 

### percentile visibility result as recommended by EPA. The results of the analysis are shown in Table 1 on the following page. The results are only presented for the Gates of the Mountains Wilderness Area, as it is the closer, and more impacted Class I Area. Details ofthe modeling are found in Appendix B ofthe original Holcim BART report. Holcim notes that this data seems to show option #1 is the most cost-effective method of reducing visibility impacts on both a dollar per ton and dollar per deciview improvement. Holcim believes, however, that this table does not represent actual emission rates or visibility impacts at the Trident plant. Table 1 does not take the effectiveness of the kiln as an 802 scrubber into account, which shows up in the tons emitted of802from the different options. Holcim analyzed the data in Table 1 using the same baseline as in the original Holcim BART report. However, as explained above, Holcim believes the baseline 802 emission rate of 124 Ibs/hr over-represents the actual emissions from the kiln. Using the average 

### 2007 802 emissions rate from the 802 CEM8 changes the baseline emission rate to approximately 13 Ibs/hr, Table 

### 2 gives a realistic estimate of tons removed, costs and visibility impacts from implementing fuel switching at the Trident plant.

Attachment A Page 43 

### » Table 1: Fuels Switching 502 

### Analysis (Baseline of 124 Ibs/hr 502) 

### fir C'l ::r CI> ;l 

### » Control Option Annualized Cost S02 Removal Efficiency (%) S02 Emission

Rate (tpy) Tons Removed Cost ($/ton) Incremental ($/ton) Gates ofthe Mountains S02 Impact (deciview) Deciviews (24 hr**-~)** Cost ($/dc) Incremental ($/dc) Option 4:100% Coal $659,651 62% 205 338 $1,954 -$37,447 1.324 0.24 $2,795,597 -$203,335,937 Option 3: Using 25% Coke with a 2.9% Sulfur $3,215,480 50% 274 269 $11,941 $65,672 1.337 0.22 $14,393,936 $356,601,667 Content Option 2: Using 25% Coke with a 3.5% Sulfur $1,620,480 45% 298 245 $6,614 $18,940 1.341 0.22 $7,402,206 $102,841,759 Content Option 1 :Using 25% Coke with a 5.3% Sulfur $240,515 32% 371 172 $1,397



### -­ 1.354 0.21 $1,170,388


### -­ Content Baseline: Using 40% Coke with a 5.3% Sulfur $0 0% 543 0


### -­ -­ 1.56


### -­ -­ -­ Content

"'U OJ <C CI> U13 

### Table 2: Fuels Switching 502 

### Analysis (Baseline of 13 Ibs/hr 502) 

### » 

### fir n ::J CD ;l 

### » Control Option Annualized Cost Efficiency (%) S02 (tpy) Tons Removed Cost ($/ton) Incremental ($/ton) Gates ofthe Mountains S02 Impact (deciview) Deciviews (24 hr
- M Cost ($/dc) Incremental ($/dc) Using 100% Coal $659,651 62% 22 35 $18,637 -$357,090 1.290 0.0065 $101,065,953 -$1,936,447,863 Option 3: Using 25% Coke with a 2.9% Sulfur $3,215,480 50% 29 28 $113,874 $626,276 1.291 0.0052 $617,520,202 $3,396,206,349 Content Option 2: Using 25% Coke with a 3.5% Sulfur $1,620,480 45% 31 26 $63,077 $180,614 1.292 0.0047 $342,057,924 $979,445,328 Content Option 1 :Using 25% Coke with a 5.3% Sulfur $240,515 32% 39 18 $13,325

-­ 1.293 0.0033 $72,258,844

-­ Content Baseline: Using 40% Coke with a 5.3% Sulfur $0 0% 57 0
-­ -­ 1.297

-­ 

### -­ -­ Content Note: Baseline emissions of57 tons/yr were based on the average CEM data at the Trident plant 2007 under normal operating conditions. The average 802 emissions during those years was 13.1 Ibs/hr. This is 89.5% lower than the permitted limit.

"1J OJ <0 CD 0>

### Based upon the modeling results, the use of fuel switching, in practice, will result in negligible visibility improvement. Even when using the best figure for control at 62%, this option has a projected 0.0065 deciview impact on visibility. This change in visibility at the nearest Class I Area is imperceptible. The costs of any of the fuel blend options, on a dollars per deciview improvement are astronomical. Select BART 

### Of the alternative fuel blending options identified above, none achieve a perceptible visibility improvement, and none are economically feasible at the Trident facility. Therefore, no new fuel blending requirements for S02 control are proposed under the BART program. Holcim proposes to continue to employ the baseline of proper kiln design and operation and comply with the existing S02emission limitation (124 Ibs/hour on a rolling 30-day basis). EPA Comment#3

• The BARTanalysis estimatesthe purchasecostfor a venturiscrubber at $14,500,500. We havecostestimate informationforventuri scrubbersthatis significantly less than the cost estimateyouprovided. Pleaseprovide documentationfor thispurchase cost. Holcirn Response 

### In responding to this comment, we have discovered an error in our cost analysis for the venturi scrubber. The value of $14,500,000 was mistakenly put into our cost analysis as the purchase cost. Holcim had estimated this value to be the approximate Capital Cost Investment (purchase and installation costs combined). Holcim has performed a revised and more detailed site-specific cost analysis for the venturi scrubber. The new purchased cost is estimated to be $2,703,683. Holcim has provided the spreadsheet showing the new cost analysis as Attachment Bto this letter. Because other tables of the original BART report rely on this cost information, Holcim has revised the tables in the report addressing purchased and installed costs for the venturi scrubber, cost analyses for performance on a dollar per ton removed and dollar per deciview improvement basis. The tables that have been revised are Table 4-2: Summary of S02 Cost Analysis on page 4-11 and Table 4-3: Summary of S02 Visibility Impacts on page 4-12 of the original BART report. The revised tables are presented below. In addition, we have discovered a mathematical error in the original Table 4-3: Summary of S02 Visibility Impacts. The two cells containing the Cost in dollars per deciview ($/dc) for the Wet S02 Scrubber and the Spray Dry Absorber were calculated incorrectly. The revised table below corrects that error as well

Attachment A Page 7

### fSO etA

### nalysls

. 

### U

'Pi

### ddT ate able42


## - 

# . Summary 0 

### 2 os I 502 Control Option Estimated Annualized Cost Efficiency (%) Wet S02 Scrubber $5,334,982 95% Spray Dry Absorber (includes baahouse) $6,070,650 90% Baseline $0 0% Emissions (Ibs/hr)

6.20

12.40

124 502 Emissions (tpy) Tons Removed Cost ($/ton) Incremental ($/ton)
27 516 $10,342 -$27,090

54 489 $12,422



### -­ 543 0


### -­ -­ Updated Table4-3: SummaryofS02**Visibili~** 

### Impacts Gates ofthe MountainslYellowstone National Park Estimated 502 Control Option Annualized Cost Efficiency (%) Emissions (Ibs/hr) S021mpact (deciview)b Deciviews (24 hr
-

### M Cost ($/dc) Incremental ($/dc) Wet S02 Scrubber $5,334,982 95% 6.20 1.291 0.269 $19,847,404 -$147,133,624 Spray Dry Absorber (includes baQhouse) $6,070,650 90% 12.40 1.296 0.264 $23,012,321

-­ Baseline $0 0% 124 1.56 0.000


### -­ -­

EPA Comment#4

• The conclusionspresentedinTable 4-2 and otherparts ofthis docwnent are drivenbythe highcapital equipmentcosts**f~r** thewet scrubber. Iftheinformationrequested above differs fromtheoriginalestimatedcostof$14,500,500, we askthat Holcimreanalyzethe**part~** of theBARTanalysisthatareaffected bythis figure. 

### Holcirn Response A purchase cost of $2,703,683 

### was updated in the cost analysis tables and is provided as Attachment B. Although the purchased cost of the Wet S02 Scrubber has dropped dramatically, the error in Table 4-3 

### has artificially lowered the costs on a dollar per deciview change for both the Wet S02 Scrubber and the Spray 

### Dry Absorber. The corrected Table 4-3 

### now shows lowered annualized costs, but increased the costs for both technologies on a dollars per deciview improvement basis. The data presented in the revised tables does not change Holcim's conclusions about the use of either S02 control technology. Both technologies listed in Table 4-3 

### above have similar performance and similar costs. Holcim believes that the cost in dollars per deciview for either technology is excessive. Holcim also believes that the annualized

Attachment A Page 8

### costs of 5 to 6 million dollars per year are unwarranted when the visibility improvement is 0.264 to 0.269 deciviews, which is not detectable by the human eye. In addition, Holcim also wants to re-emphasize that the above analysis was based on the current emission limit of 124 Ibs/hr. Holcim believes this greatly exaggerates actual 802emissions, and overstates any 802 reduction and visibility improvements made by the addition of 802controls to the kiln. Of the two alternative 802 control technologies identified above, neither is economically justified or produces a perceptible result. Therefore, Holcim proposes to continue to employ the baseline of proper kiln design and operation and comply with the existing 802 emission limitation (124 Ibs/hour on a rolling 30-day basis). No new requirements for 802are proposed underthe BART program.

EPA Comment#5

NOxEmissions andControls

• Section4.4 ofyouranalysislistsproperkiln designand operation as oneofthepossible control options and as the baseline inthe analysisforothercontroloptionsbutdoes not provideinformationonthe current designand operationofthe**kiln~** Pleaseprovide informationonthecurrentkilndesign and operation and ananalysis onwhetheradditional reductions canbeachieved throughproperkiln design andoperation. Holcim Response 

### The current kiln, which was constructed in 1973, is a long, wet kiln design. Holcim believes the kiln is well designed for its intended purpose, a relatively low production facility. (More typical cement plants constructed in the past 30 years have been much larger). Holcim operates the kiln to minimize NOx emissions while still meeting product quality requirements. Holcim is always searching for ways to improve product quality, production efficiency and emissions performance. To that end, Holcim has worked with the kiln and control system for many years to minimize NOx emissions. Holcim employs extensively trained kiln operators, uses a state-of-the-art computer control system and operates a NOx CEM8 in an effort to monitor and minimize NOx formation. Through years of experience and optimization, Holcim believes the kiln is operated properly and no further NOx reductions can be I 

### made without design changes or add-on controls. Holcim has performed an analysis on theoretical and practical ways to reduce NOx emissions, as listed in pages 4-12 through 4-14 of the BART report. Holcim identified several changes to the system, including increased thermal efficiency through improved clinker cooler sealing, and decreased combustion temperatures through the switch to a low NOx burner and other combustion system changes. These are changes to the existing design and methods of operation that were not envisioned when the kiln was

Attachment A Page 9

### constructed. The low NOx burner and combustion system modifications achieve all five of the theoretical ways to reduce NOx formation as spelled out on page 4-13. Holcim believes changing the kiln to another design, such as pre-heater dry kiln, may lower NOx emission rates, and it would be theoretically possible to implement a fundamental change to the kiln and plant design. Holcim also believes that the practical and economic realities of such a change preclude this from actually being done (See response to EPA comment #11). In addition, a complete rebuilding ofthe kiln and plant layout to accommodate such a change goes far beyond the scope of BART. The BART program is meant to apply a retrofit technology to an existing source, not to replace the source itself. Holcim only meant for the phrase "proper kiln design and operation" to serve as the baseline case of existing equipment operated to minimize NOx formation, and that any identified improvements would be clearly spelled out as retrofits to the existing system.
EPA Comment#6

• In additiontothe installationofa fixed inletto the clinkercooler and the installation ofalow NOxburner, Holcim should continueto considermid-kilnfiring and SelectiveNon-Catalytic Reduction (SNCR) as viableBARTcontroltechnologies forNOxemissionreduction. Mid­ kilnfiring is expectedto achieve an emissionreduction of45%ormore (see**H~en,** Eric R TechnicalConsultant, CadenceEnvironmentalEnergy Inc. "StagedCombustionforNOx Reduction Using HighPressureAirInjection."IEEE2002). SNCRhas been ap:pliedto wet kilns and canreliably attain aNOx emissionrate of800mg/m3, and inmostcases attaina rate of500mg/m3 (see Scur, P. CemexOstzement,Red.ersdorf. Hoppe, Dr, Forchunginstitut derZementindustrie, Dusseldorf. "ThePresent State ofNOx Abatementwiththe SNCR Process.",CementInternationalNo. 2/2006,Volume4.,ISSN 1610-6199 andAssessmentof NO x EmiSsionsReductionStrategies for CementKilns

- Ellis County...,. FinalReport. Preparedby ERG, Inc

..for Texas CommissiononEnvironmental Quality. TECQ CotractNo. 582-04-65589, Work OrderNo; 05..Q6. July 14,2006). Pleaseprovide additional analyses anddocumentation for bothofthese potential control measures. Holcim Response 

### Mid-Kiln Firing ofTires Holcim wants to again emphasize that the use of tires is prohibited by Montana rule unless an air quality permit authorizing the incineration of tires is issued to Holcim. As detailed in the BART report, Holcim applied for such a permit in 2001, and it has yet to be issued. The permit is waiting for completion of a Montana Environmental Impact Statement by the Montana Department of Environmental Quality (DEQ). It appears that the probability of receiving a final permit free of legal challenges within the next few years is very low. Holcim cannot commit to the use of mid-kiln injection oftires, nor can Holcim commit to a lower NOx limit achieved through the use of tires. Therefore, Holcim believes any analysis of exactly how much NOx reduction can be achieved is irrelevant, since this system is not proposed as BART and cannot, by rule, be installed.

Attachment A Page 10Selective Non-Catalytic Reduction (SNCR) Since the initial BART submittal in July of 2007 and at your suggestion, Holcim has continued to research the possibility of applying SNCR-type technology to its kiln operation at Trident. After considerable review as it applies to Trident and other installations, we have come to believe that indeed an SNCR-type oftechnology may be possible, at least on a trial basis, for the kiln at Trident. To that end, Holcim proposes to forgo an extensive re-analysis of BART for NOx for the kiln, and commit to install, on a trial basis, an SNCR system on the kiln. Holcim believes that an SNCR would offer at least a 30% NOx reduction, which would make it equal to or better than the best performing NOx reduction technology identified in Table 4-4 of Holcim's BART report. Holcim would install, operate and test the new SNCR system for a period of time (one year for example), analyze the actual NOx reductions achieved from that system, and then propose a new BART-derived limit for NOx for the kiln. As of the date of this document, Holcim has not chosen a specific SNCR system to install. Therefore, technical details of the proposed system will not be known until the required research is completed. Holcim is aware of two styles of SNCR which could be retrofitted to the kiln. One uses a solid pelletized form of urea, which could be mechanically introduced into the existing "dust scoops" mechanism. The other would involve a system to inject liquid urea into the proper temperature zone in the kiln. Holcim believes it can start the trial process by installing the necessary equipment to study the proper temperature zone in the kiln. This will be accomplished by installing a series of thermocouples in the kiln shell during the planned annual outage during April of 2009 Following installation of the thermocouples to determine the proper temperature zone, Holcim will engineer and procure the associated equipment for installation of the trial SNCR in approximately April of 2010. Trials would occur over the next year with the intent ofestablishing an agreed upon reduction limit within one year, by April 2011.
EPA Comment#7

• Table 4-4 liststhe efficiency for mid-kiln injection oftires as 30%. A value of40%for wet kilnshas been documented and we request that Holcimprovide arevised analysis forthis

.

. control optionusing a value of40% for the wetkilnor

### an analysis ofwhy 40%is pot

achievable (seeNOxControl Technologies for the CementIndustry. Battye, R., SWalsh,J. Lee-Greco, ECIRIncorporated preparedforU.S. EPAundercontractNo. 68-D-98-026. September 19,2000. Table 5-7). Holcim Response Obviously, Holcim does not have direct experience of expected NOx reductions from the use of TDF at the Trident facility. Rather, Holcim has relied on other studies of

Attachment A Page 11actual installations elsewhere to estimate NOx reduction efficiency. Holcim used 30% as a conservative number taken from other studies. In examining the EPA referenced document, an average of 40.5% NOx reduction was reported in Table 5-7 on page 67, but the lowest value reported from the three wet kilns was a 27.5% reduction. Also, in Table 5-9 on page 75, which summarizes the NOx reductions cited for European kilns, a range of 20-40% reduction is listed. Given the variable nature ofthe existing data, the low number of similar installations and a lack of data on how mid-kiln injection of tires would actually perform at Trident, Holcim felt choosing a conservative but reasonable value of 30% was appropriate. Holcim feels that a 40% reduction may be achievable, but to base the entire BART analysis and a new NOx limit on 40% is foolhardy, as this number mayor may not actually be achieved in practice. In addition, as stated in the response to #6 above, Holcim will likely not be permitted to use TDF in the timelimes outlined in the BART regulations. Therefore, the use ofTDF is not achievable and cannot be BART.
EPA Comment#8

• Thedocument states thatdetails ofthe costanalysis for low-NOxburners, and mid-kilnfuel injection are included inAppendixC. However, Appendix C did /)ot include theseanalyses. Please submitthe details ofthecostanalysis for 10w-NOxburners andmid-kiln injection.' Holcim Response Holcim was incorrect in stating that a cost analysis for either of these control technologies could be found in Appendix C. Section 4.4.4 of the report explains the details ofthe cost analysis for the annualized cost of LNB and mid-kiln firing conversion. As stated in Section 4.4.4, page 4-23 of the report, Holcim referenced the guidance document EPA NOx Control Technologies for Cement Industry Final Report, (9/19/00), Table 6-8 for costs of 10w-NOx burners and Table 6-10 for costs of mid-kiln fuel injection. Holcim used a 1.25607 CPI multiplier to adjust to 2006 dollars. Table 6-8 estimates an annualized cost of $389,000 (1997 dollars) for retrofit LNB installations for a 50 ton/hr long wet kiln. It is assumed this is a representative cost. The adjusted annualized cost was calculated to be $498,065. Table 6-10 estimates an annualized cost of $370,000 (1997 dollars) for mid-kiln firing conversion for a 50 ton/hr long wet kiln. It is assumed this is a representative cost. The adjusted annualized cost was calculated to be $473,738.

EPA Comment#9

• Using thepermittedNOxemissionrate to determinetons ofNOxremoved is problematic. Thepermittedvalue is very highrelativetothe actual emissions. ThemaximumNOx
Attachment A Page 12emissionrate during the three yearperiod of2001-2003 was reported as 7841bslhour. The permitted value is 1,568 Ibslhour, ortwicethe maximumvaluereported for the threeyear period. Using thepermitted value as the baseline could give a calculatedpost control emission rate largerthan the actual uncontrolled emissions. Forexampleproposing a 20% NOxreductionwitha pennitlimitation of 1,254 Ibslhourwould allow anemission increase from the currentlyreportedmaximumhourly rate of784Ibslhour

..Itis appropriate to use actual emissionsifthose are representative ofhowHolcimhasbeenoperatingin the past. In addition, Holcimused actual emissionsto model visibility for the BARTanalysis and the emissionsused inthe modeling and the rest ofthe analysis needto beconsistent. Please t;evise theanalysis using actual emissions. Holcim Response 

### We have reviewed your concern regarding the fact that the permitted emission rate for NOx (1,568 lb/hour) is higher than the actual reported rate (24-hour max) of784 Ib/hour. We offer several observations and the rationale for our use ofthe permitted rate. 1. Applicability. To begin, the 24-hour maximum rate was used primarily, in our OpiniOn, for applicability purposes. The term applicability here refers to the determination of which sources are "BART-eligible sources" (those sources that primarily meet the requirements of 40 CFR 51, Appendix Y, Section II) in conjunction with those sources that are determined to be "subject to BART" (40 CFR 51, Appendix Y, Section 111.1). The "subject to BART" analysis was conducted by EPA and the results are summarized in your February 28, 2007 letter. The letter includes a summary of dispersion modeling results, including indirect references to the actual emission rates, and requesting Holcim to conduct BART engineering studies. To that end, the BART Guideline (40 CFR 51, Appendix Y) and the Montana "Modeling Protocol For Federal Mandatory Class I Areas,,1 require that the emission rate used in the dispersion modeling be the "24-hour average actual emission rate from the highest emitting day of the meteorological period, unless this rate reflects periods of start-up, shutdown, or malfunction."z Once an applicability determination is (was) made, then its use is not necessarily required for continuing analyses of defining an appropriate BART technology. That is not to say that the "actual" values would necessarily be ignored. However, we believe we have provided a more conservative approach to the NOx BART analysis by using the allowable emission rate in the technology analysis section of our July, 2007 submittal. Additional information is provided below.

1 http://www.epa.gov/Region8/air/pdf/MontanaBARTProtocoI0906.pdf. 2 40 CFR 51, Appendix Y, Section 11I.A.3.

Attachment A Page 13

### 2. Conservative Analysis.
Your comment: "Using the permitted values as

### a baseline couldgive 

### a calculatedpost controlemission rate larger than the actual uncontrolled emissions. " 

### This sentence appears to be misleading. The discussion intimates that any control technology that could be applied (to Holcim) will yield a larger emission reduction rate than starting the comparison from the actual emission rates. The statement is factually correct, but its implied impact (the selection of a BACT technology that is inappropriately weak) is not. The selection of BART is based on a number offactors. Once all ofthe infeasible or otherwise inappropriate technologies are eliminated, the selection ofthe "final" BART is based, in large part, on the cost-effectiveness of the remaining technologies coupled with visibility improvements, all other factors being equal. This analysis is typically expressed as an annualized cost of the alternatives divided by the reduction in emissions from each control. 3 

### Once a particular technology is considered, the cost of that technology remains fixed within the parameters of this discussion regardless of the emission rate. The final cost-effectiveness figure depends on the denominator of the equation, the tons ofemissions reduction. From that perspective, the selection of a less stringent BART technology would be favored by using the actual emission rate. 

### If that were done, then the costeffectiveness of the control technologies would be about one-half the costeffectiveness of the same strategy if one uses the permitted figures (as Holcim has done). For the BART analyses conducted in the July 2007 submittal along with this document, Holcim has chosen to use the permitted emission rate for consistent analysis. Such a technique has led to an artificially low cost-effectiveness of available technologies. Therefore, the approach is a conservative one for the BART program. Regardless, it is clear both from the July 2007 submittal and this document that the use of either the actual or permitted values for NOx would not change the selected control technology. This submittal proposes to use the most effective feasible control technology for purposes of NOx control:

3 See Steps 3 and 4 Section IV.D ofAppendix Y (70 FR 69164, etseq.)

Attachment A Page 14• fixed clinker cooler inlet; combustion system modification (low NOx burner); and • a demonstration project SNCR

. Therefore, no additional analyses are necessary nor would they lead to an alternative technology selection. EPAComment#10 ParticulateMatterEmissions andControls

• Holcimdidnotprovide any designparameters forthe existingPM controltechnologies on the ESP onthe kiln andthe baghouse onthe clinkercooler. Itis possiblethatBARTforPM forthese two sources couldinclude additional controls and/orincreasedperfonnance of, the existingtechnologies. TheBARTGuidelines statethat**~'For** emissionunits subject to a BARTreview, there will oftenbecontrolmeasuresordevices already inplace. Forsuch emissionunits, itis importantto includecontrol options thatinvolveimprovementsto existing cO!1trolsandnotto limitthecontrol options only tothOsemeasures thatinvolve a

, completereplacement ofcontrol devices" (see 70FR 39164, July 6, 2005). We askthat

Holcim submitthe designparameterinformationfor PM controls onthe kilnand clinker coolerandevaluatethepossibility ofadditional controls and increasedperfonnance ofthe existingequipment. ' 

### Holcim Response The ESP on the kiln has a 99.9%+ control efficiency as estimated by Holcim and independently estimated by Montana DEQ (referenced in the BART report). The baghouse on the clinker cooler also has an estimated 99.9%+ control efficiency. Holcim believes these control system performance figures to be typical for modern installations. In the most recent stack testing on each source, the ESP tested at a total particulate emission rate of 0.0146 gr/dscf (Sept 2007), and the clinker cooler baghouse tested at 0.0139 gr/dscf (Oct 2006). These emission rates are consistent with sources at similar facilities, and represent the highest level of control that is achieved in practice with the same device; therefore, the existing controls were chosen as BART and were not further analyzed. In Holcim's opinion, the phrase that reads "it is important to include control options that involve improvements to existing controls" means that a system not performing to modern standards could be rebuilt for improved performance. For example, an existing older S02 scrubber achieving a 70% S02 reduction could be brought up to modern standards and be made to achieve a 90 or 95% reduction. In this case, Holcim is not aware of any improvements that could be made to increase the performance of the existing systems. Methods to improve the performance of the existing ESP and baghouse were not evaluated because the BART Guideline states that, "if a source commits to a BART determination that consists of the most stringent controls available, then there is no need to complete the remaining analyses in this section."

Attachment A Page 15EPA Comment#11
Overall Comments

• Youranalysisdidnot include a conversion from a wetkilnto a semi-dry or dry kiln. Several documents intheliterature indicatethatboth ofthese demonstrated options would offer substantial emissionsreductions at'potentiallyreasonablecosts (seeAssessmentof NO x Emissions Reduction Strategiesfor CementKilns

- Ems Co.unty

- FinalReport. Prepared by ERG,Inc. for**Te~as** CommissiononEnvironmental Quality. TECQ CntractNo. 582-04­ 65589, WorkOrderNo. 05-06. July 14,2006and A UniqueApproach. Menke, T., Jepsen. O.L., and Keefe, B.P. ReviewNo. 136. Reprintfrom IEEE-IASIPSCA 2001 Cement industry Technical Conference May 2001 andpublished inInternational CementReview, July 2001). Please include ananalysis thataddresses a conversionfrom a wetkilnto a semi­ dry ordry kiln. Holcirn Response 

### As mentioned in the response to comment #5, Holcim believes changing the kiln to another design, such as a pre-heater, pre-calciner or dry kiln would lower NOx emission rates on a pound per ton of clinker produced basis. There are no major technical challenges to convert the plant to one of those designs. The challenges come in the economic realities ofsuch a change. To modify the kiln design would actually require a re-configuration of much ofthe rest of the plant as well. Holcim converted its Devils Slide, Utah plant to a dry kiln in 1998. Holcim reported the total cost at $133 million. In todays dollars, that figure exceeds $200 million. Furthermore, Holcim and its competitors already serve a market that is smaller than its capacity. The Portland Cement Association projects that the Montana market demand will not exceed capacity for approximately 20 years. Therefore, the market demand simply does not exist at this time to satisfy the construction a plant with the capacity of the Devil's Slide plant, the smallest of any Holcim plants recently constructed. To construct a dry plant the size of the existing Trident plant simply to reduce NOx emissions (other BART related criteria pollutants would be nearly the same) would simply be uneconomical. Holcim believes that a reconstruction of the kiln and supporting plant structure goes far beyond what is meant by a "retrofit technology" under the meaning of the BART program. The BART program is meant to apply a retrofit technology to an existing source (constructed 1962 to 1977), not to replace the source itself. If the kiln were redesigned and replaced, the kiln would be a new or re-constructed source, and would fall outside of the authority of the BART program. The kiln would be permitted under the Montana PSD permitting process, which would then address modeling and visibility issues at Class I and other areas.

Attachment A Page 16EPA Comment#12
There are also several locations inthe documentthatmay havetypographical errors.

• Onpage 3-3 inSection 3.3 it states thattheBARTmodeling analysis perfonnedfor Holcim used thepennittedNOx PTEto establishthe baseline visibility impacts. The pennittedvalue is givenas 1,568 Ibslhrona rolling 30-day average (6,868 tons/year). As provided inTable 3-2,the rate thatwas modeled is 784 lbslhour.

. . 

### Holcim Response Section 3.3 of Holcim's BART report is correct; the permitted limit of 1,568 Ibs per hour was used by Holcim for NOx reduction modeling and associated visibility analysis. Table 3-2 refers to the initial applicability test and modeling performed by EPA, where the highest actual 24-hour rate of 784 Ibs/hr was used. See response to Comment #9 for further information. EPA Comment#13

-. Onpage4-11 the secOnd technology analyzed 'wet S02 scrubberimpacts' begins with a (c) ratherthan a (b). Is there a missing analysis? 

### Holcim Response No, this is a typographical error. It should read (b) Wet 502 ScrubberImpacts. EPA Comment#14

• On**p~ge 4~23**  theweb address forthe CPI multiplierdoes notwork. 

### Holcim Response This link was successfully used after reading this comment. It is http://www.rninneapolisfed.org/research/data/us/calc/.

Attachment A Page 17----

--- Appendix 8 -CONFIDENTIAL- Trident Plant A<;tual Emissions S02 Emissions (lpy) 543 Airflow (acfm) 172959 Production (tpd) 957.6 Direct Costs Purchased Equipment Cost· Scrubber $2.073,683 xponentJal scaling using an exponent of 0.7 and ratio ofTrident Kiln to Model Plant B flowrate of238.800 acfm in PCA Report I xponential scaling using an exponent of 0.2 and ratio ofTrident Kiln to Model Plant B f\Owrate of238,800 acfm in PCA Report Purchased Equipment Cos!
- Waste Water Treatment Plant $750,018 IE

I xponential scaling using an exponent of0.7 and ratio ofTrident Kitn to Model Plant B fIowrate 01 238,800 acfm in PCA Report. PCA Total Cost ofScrubber and New Stack $6,223,444 t ased their value on sum of Purchased Equipment Cost, Direct Installation Cost, Total Direct Cost arld Totallrldired Cost Total Cost of Waste WaterTreatment Plant $1,875,045 I xponent\aJ scaling using an exponent of0.2 and ratio of Trident Kiln to Model Plant Bflowrale of 238,800 acfm in PCA Report Total Capital Investment (TCI) $8,098,489 DirectAnnual Costs

Hours perYear 7,680 I xpected annual operationfor PCA cost estimates OperatinQ Labor Operator $219,150 I stimate from PCA Suoervisor (15% ofooeratorl $32,873 ( CCM (and PCA) Subtotal, Operating Labor $252,023 Maintenance Maintenance (labor and materials) 20% of Purchasing Cost $564,74[ Subtotal, Maintenance $564,74' Lost Production 

# if:;, 

# I? ((Of, Cost of Lost Production @ $30/ton $317,7 Subtotal, Lost Production $317,;



# _ ..**~-**

# -;i-"'-­

Utilities Electricity 

# 3 Pump (kW) Fan (kW) Cost ($lkW-hr) $[ 

# r ('

## ~f r;;:;. Subtotal, Electricity $4' ./ /
Water 

# &
Amount Required (Iblhr)**~.** Cost 

# a Subtotal, Water Reagent (NaOH) Amount Required (tpy) "c, 

## S" $5'J() 1R1 NaOH Cost (50% liq. Caustic soda. $300rr)) $5 ("":l Subtotal, Reagent Acid Wash**(,i-<.~~** Amount Required (ton/yr) 

# T ?rcf' Ir Ie'

# 9 o

Cost ($Iton) ! ,....,-1/ 'i 0 , Subtotal, Acid Wash 

## , 01f/ C/ Waste Water Disposal (Slurry) Amount Required (tpy) , " 

# = t:t. Cost ($Iton) 

### ----, Subtotal, Waste Disposal (Slurry) 

# a**~.** 

### 7**~~.**

# 'I**<~,~** Blowdown Disposal Costs Amount Required (ton/yr) 

## f 3/!l73,V0 

## 9 

# 4",,!\4 Cost($lton) 

# o Subtotal, WasIe Disposal (Solids)**-~--=---:--L&** rf

### Lj**~/~C;D(p** 

# e· Subtotal, Utilities ( 

# a

Total Dired Annual Costs IndirectAnnual Costs

Overhead (60% ofsum of operating, supervisor, maintenance labor & matenals) $490,058 PCA report agreed wi OAQPS CCM percentage Administrative (2% TCI) $161,970 PGA report agreed wi QAQPS CCM percentage PropertyTax (1% TCI) $80,985 PGA report agreed wI OAQPS GCM percentage Insurance (1 % TCI) $80,985 PCA report agreed wi OAQPS CCM percentage Ca ital Recovery (10 year life, 7 percent interest) $1,153,043 PCA report agreed wi OAQPS CCM recovery equation Total Indirect Annual Cost $1,967,040



### ,002 Price Total Annualiz.ed Cost (2002 $) $4,606,451 Scaled based on inflation to represent 2007 values (PCA used 2002). Consumer Price Index Annual Avg from 2002 = 179.9to June 2007 =208.352 Total Annualiz.ed Cost (2007 $) $5,334,982,21 Used actual emissions from 2002 Pollutant Emission Rate Prior to Scrubber (tons SQyr) S43 L Pollutant Removed (tons SQ/yr) assuming 95% removal 516 Cost Per Ton of Pollutant Removed $10,342

# SubjecttoConfidentiality

# ClaimAttachment C



### - CONFIDENTIAL
­

Trident Facilitv Fuel Consumotion Scenarios 40% Pet Coke/60% Coal BASELINE Sulfur Perc"nt -. 0 content offu"l Emissions Pet Coke 28,700 metric Ions @ 5.30% 40% 1521 Ions of uncontrolled sulfur 78% Currenl Coal 53,000 metric Ions @ 0.80% 60% 424 Ions of uncontrolled sulfur 22% TOTAL 81,700 1945 lolal sulfur= 3890 tons ofS02 

# I

Estimated fuel consumption based off of producing 289,953 metric tons of clinker per year. 6,613.9 E.G (joulesJMton c1inker))II 289,953 (Mton clinker/yr)" 1.9155 E+15 (Joulesfyr) =>1.9155E+15 lJoules/yr) J1055.06 (JOUles/Btu) '"' 1.818 E.12 (Btulyr) "'''>14,000 {Btu/lb coke) x 2,000 (Ib/Stan coke)" 2.8 E+7 (Btu/Stan coke)

........>1.818 E+12 (Btu/yr) / 2.8 E+7 (Btu/Stan coke) • (64,916 Ston coke/yr) x (1 Mton ( 1.1023 Ston) '"' 71,557 Mton coal x (40%) • 28,662 Metric ton coke per year

..........> 9,350 (Btu/lb coal) x 2,000 (Ib/Ston coal)- 1.87 E+7 (Btu/Ston coal) """""=>1.818 E+12 (Btulyr) 11.87 E+7 (BtU/Stan coal) • (97,200 Ston coal/yr) x (1 Mton 11.1023 Stan) • 88,400 Mton coal yr)( (60%) = 53,040 Metric ton coal peryear
0% Pet Coke/100% Coal Scenario Pel Cok.e o melric tons @ 5.30% 0% 0 Ions of unconlrolled sulfur 0% Current Coal 92,000 melrlc Ions @ 0.80% 100% 736 Ions of uncontrOlled sulfur 100%**TOTAL~** 92.000 736 lolal sulfur :: 1472 tons of S02 

## I

25% Pet Coke/75% Coal Scenarios 5.3% 5 Pet Coke Currenl Pel Coke 14,500 metnc Ions @ 5.30% 25% 769 tons of uncontrolled sulfur 58%

Current Coal 70,000 metric tons @ 0.80% 75% 560 Ions of unconlrolled sulfur 42% TOTAL: 84,500 1329 lotal sulfur
- 2657 tons of S02 1 3.5% S Pet Coke Current Pel Coke 14,500 metric Ions @ 3.50% 25% 508 tons of uncontrolled sulfur 48%

Currenl Coal 70,000 metric tons @ 0.80% 75% 560 tons of uncontrolled sulfur 52% TOTAL: 64,500 1068 lolal sulfur '" 2135 tons of502 1 2.9% 5 Pet Coke Currenl Pel Cok.e 14,500 metnc Ions @ 2.90% 25% 421 tons or uncontrolled sulfur 43%

Current Coal 70,000 metrIC Ions @ 0.80% 75% 560 tons of uncontrolled sulfur 57% TOTAL; 64.500 981 tolal sulfur = 1961 tons of 502 I lpy 13042 10"' or S02 rcom coke

848 Ions of 802 from coal



## I 0 100' or S02 rcom coke 1472 Ions of 502 from coal

1'537 10"ofS02fcomcoke 1120 tons ofS02 from coal 

# I'
015 lon' of S02fcom coke 1120 tons of S02 from coal

1'41 Ion"f S02fcomcoke 1120 Ions of S02 from coal

Current Cost of5.3% Sulrur Pet Coke from Billings = $27.83 IMT <---Current Conoco 3.5% Sulfur Pet Coke from California :; $123 IMT <---Option 1 Chevron 2.9% Sulfur Pel Coke Salt Lake City;: $233 IMT <---0 tion 2 

# SubjecttoConfidentialityClairn

Cost of 0 8% Sulfur coal from E Montana =I $41.22 1ST -I $37.39 IMT 40'/D Coke 60% Coal Ontion BASELINE Consumption Sulfur Annual 502 from Reduction Reduction E5timated Fuel of coke Content Cost fuel in 502 in 502 Consumotion Fuel metrictons/vr % CostiMT Baseline Ito, IlonlY'\ 1%\ Estimated Baseline Coke Pet Coke 28,700 530% $27.83 798.721 3042 Esllmaled Basehne Coal Coal 53.000 080% $37.39 I 1,981.890 848 Estimated Total Fuel Annualized Cost $ 2,780,611

25% Coke 75% Coal ODtions

Ootions Fuel Consumption of coke (metric tons/yr) Sullur Content

(%\ C05VMT Annual Coke Cost S021rom luel (tpy) Reduction in 502 (ton/yr) Reductio n inS02

(%) Coke Ootion 1 Pet Coke 14.500 5.30% $27.83 $403.535 2657.0 0 0% Coke Ootion 2 Pet Coke 14,500 3.50% $123.00 $1,783.500 2135.0 522.0 20% Coke Option 3 Pet Coke 14,500 290% $233.00 $3,378,500 1961.0 696.0 26% Note. Annualized Cost of75Yo coal =70,000 metnctons/yr)( $37.39/MT

- - $2,617,591/yr. ThIS cost IS In additIon to the coke cost above and is included in the cost analysis table below. 0% Coke 100% Coal Ontions
Consumption Sulfur S02 from Reduction Reduction

ofcoal Content Annual fuel in 502 in 502 Ootions Fuel (metric tons/yr) (%j Cost/MT Fuel Cost (tpy) (ton/yr) (%) Coal Option 1 Coal 92,000 0.80% $ 37.39 $3,440,262 1472.0 0 0% Cost Analvsis for Fuel Switchina Qations
Gates ofthe Mountains

ControlODtion Annualized Cost1 Effieienev f%\ 502 Ib/hr\ 502 (lOY) Tons Removed Cost ($/ton) Incremental ($/ton) 502 Imoact DeCiviews Ir24 hr

-**~I** Cost I$/de) Incremental ($/de) Using 100% Coal $659,651 62% 5 22 35 $18,637 -$357,090 1290 0.0065 $101,065,920 -$1,936.447,863 Option 3 USing 25% CoKe Wlth a2.9% Sulfur Contenl $3.215.480 50% 7 29 28 $113.874 $626.276 1291 0.0052 $617,520.160 $3.396.206.349 Option 2' USing 25% Coke With a 35% Sulfur Canten! $1.620.480 45% 7 31 26 $63,077 $180,614 1.292 0.0047 $342.057.878 $979,445.328 Option 1Using 25% Coke With a 5 3% Sulfur Canlent $240.515 32% 9 39 18 $13,325
-­ 1.293 0.0033 $72.258.780

-­ Baseline' USing 40% Coke wilh a 53% Sulfur $0 0% 13 57 0
-­ -­ 1.297

-­ -­ -­ Content Annualized cost Option Cost = Baseline Cost 2 The baseline is based offthe 2007 CEM's data that averaged 13.1 lbs/hr of S02. This is calculated to be 57 tons/yr, which is 89.5% lowever than the permitted limit.