MEMORANDUM

DATE: March 29, 2012 

SUBJECT: GCC Dacotah - NOx Emission Reduction and Cost Calculations 

FROM: Mike Owens, Environmental Engineer 

Air Permitting, Monitoring & Modeling Unit 

 

TO: Monica Morales, Chief 

 Air Quality Planning Unit 

 

The purpose of these calculations is to provide background information for the docket for EPA 

Region 8’s rulemaking on final approval of the South Dakota regional haze SIP submittal. GCC 

Dacotah is listed as a Reasonable Progress source in the SIP submittal. 

Some of the comments EPA received on its proposed approval of the SIP submittal involved the 

possibility of obtaining further NOx emission reductions at Kiln #6, for purposes of visibility 

improvement. The current NOx controls consist of “staged combustion with a thermally 

efficient, in-line, low-NOx calciner complimented by a low NOx burner with indirect firing in the 

rotary kiln.” (ref: page 4-16 of January 16, 2002 PSD permit application by GCC Dacotah for 

Kiln #6 system.) Commenters presented arguments why Selective Non-Catalytic Reduction 

(SNCR) should be installed. 

South Dakota considers SNCR to not be feasible unless a large new pre-calciner is installed, to 

provide an adequate temperature profile for SNCR to work, at 1600o F or higher. (ref: 10/11/11 

email from Kyrik Rombough of SD DENR to Gail Fallon of EPA Region 8.) Kiln #6 currently 

has a small pre-calciner. Trinity Consultants provided a “BACT Cost Estimate for Large 

Calciner,” dated March 13, 2003, which estimated the cost and potential NOx emission 

reductions from installation of a large pre-calciner. EPA does not have any data from SD DENR 

on what SNCR might cost at GCC Dacotah, if a large pre-calciner was also installed to 

accommodate SNCR. 

The only NOx emission limit in the current South Dakota PSD permit for the kiln #6 system is 

2,267 tons per rolling 12-month period. (ref: Condition 4.2 of SD DENR Permit #28.1101-

PSD.) Actual NOx emissions for 2008-2010 averaged 816 tons per calendar year (tpy) and 2.96 

lb/ton clinker. (ref: xcel spreadsheet, attached to 03/20/12 email from Kyrik Rombough of SD 

DENR to Gail Fallon of EPA Region 8). 
These EPA calculations are based on the following assumptions and bases: 

1. EPA Region 8 is relying on SD’s statement that a large pre-calciner system would need 

to be installed, if SNCR is to be accommodated at Kiln #6. A 10/11/11 email from Kyrik 

Rombough of SD DENR to Gail Fallon of EPA Region 8 states that a larger calciner 

system "may have had an appropriate location" for SNCR and was considered during the 

2003 PSD BACT analysis. 

2. EPA Region 8 is relying on Trinity Consultants’ estimated costs and NOx emission 

reduction achievable by a large pre-calciner to be reasonable estimates. Trinity’s cost 

estimate does not include the cost of SNCR, just the cost of the large pre-calciner itself. 

It also does not include the cost of dismantling and removing the existing small precalciner. (ref: BACT Cost Estimate for Large Calciner, Trinity Consultants, March 13, 

2003.) It is important to note that the large pre-calciner, by achieving NOx reductions of 

955 tpy, is acting as both process equipment and emission reduction equipment. 

3. EPA Region 8 is relying on an EPA-OAQPS document which indicates that SNCR can 

be expected to achieve 50% emission reduction at a preheater/precalciner kiln. EPA 

Region 8 is also relying on the estimate of annual cost of SNCR to be a reasonable 

estimate, in 2005 dollars. (ref: Alternative Control Techniques Document Update – NOx

Emissions from New Cement Kilns, EPA-453/R/07-006, November 2007, page 111, 

Table 12-2, “SNCR and SCR Costs for Preheater/Precalciner Kilns in 2005 Dollars”) 

4. EPA Region 8 assumes that EPA-OAQPS’s estimate of cost for SNCR at a 100 ton-perhour kiln is a reasonable approximation to the cost for SNCR at a 94 ton-per-hour kiln. 

(ref: same as item 3 above.) 

5. Consumer Price Index (CPI) scale-up factor from 2003 to 2011 dollars is 1.22. Scale-up 

factor from 2005 to 2011 dollars is 1.15. 

Calculation of current NOx reduction: 

PTE of Kiln #6, uncontrolled, at production capacity: 2,152 tpy. 

(ref: Table 3-2 of the 2002 PSD permit application for GCC Dacotah) 

2008-2010 actual average clinker production: 550,483 tpy. 

(ref: xcel spreadsheet, attached to 03/20/12 email from Kyrik Rombough of SD DENR to Gail 

Fallon of EPA Region 8) 
Kiln #6 system design capacity clinker production: 2,250 tons per day, equivalent to 821,250 

tpy. (ref: page 3-2 of January 16, 2002 PSD permit application by GCC Dacotah, revised 

August 31, 2002) 

Therefore, during 2008-2010, Kiln #6 operated at: 550,483 / 821,250 = 67% of capacity, on 

average. 

Potential uncontrolled NOx emissions at 67% of capacity: 2,152 x 0.67 = 1,442 tpy. 

2008-2010 actual average controlled NOx emissions: 816 tpy (equivalent to 3.0 lb/ton clinker). 

(ref: xcel spreadsheet, attached to 03/20/12 email from Kyrik Rombough of SD DENR to Gail 

Fallon of EPA Region 8) 

 

Current percent reduction from uncontrolled NOx emissions, at 67% of kiln capacity: 

[1,442 – 816] / 1,442 = 43.4% reduction. 

Controlled emissions at capacity: 816 tpy / 0.67 = 1,218 tpy 

CONTROL UPGRADE SCENARIO #1: REPLACE EXISTING NOX CONTROL 

SYSTEM WITH A NEW LARGE PRE-CALCINER, BUT WITHOUT SNCR 

Calculation of cost and emission reduction for new large pre-calciner, to replace current NOx

control system, but without installing SNCR: 

As noted in assumption/basis item #2 above, Trinity Consultants has estimated that a new large 

pre-calciner alone (without SNCR) could achieve NOx emission reductions of 955 tpy, therefore 

acting as both process equipment and emission reduction equipment. 

Capital cost: $34,523,546 (2003 dollars). Total annual cost: $4,823,925 (2003 dollars). 

Emission reduction from potential uncontrolled emissions, at kiln capacity: 955 tpy. 

(ref: BACT Cost Estimate for Large Calciner, Trinity Consultants, March 13, 2003.) 

Potential controlled emissions at capacity: 2,152 – 955 = 1,197 tpy. 

 

Reduction from current controlled emissions, at capacity: 1,218 – 1,197 = 21 tpy. 

(This is the basis for the incremental cost-effectiveness calculation below.) 
The total cost-effectiveness calculation below is the annualized cost of a large new pre-calciner, 

divided by the emission reduction expected to be achieved by the new pre-calciner from potential 

uncontrolled NOx emissions. 

Total cost-effectiveness (2003 dollars): $4,823,925 / 955 = $5,051/ton. 

Total cost-effectiveness (2011 dollars): $5,051 x 1.22 = $6,164/ton 

The incremental cost-effectiveness calculation below is the annualized cost of a large new precalciner, divided by the emission reduction expected to be achieved by the new pre-calciner from 

current controlled NOx emissions. The incremental cost-effectiveness analysis uses the same 

annualized cost as the total cost-effectiveness analysis because the cost of achieving the current 

controlled emissions is zero, i.e., current controls are already installed and operating. 

Incremental cost-effectiveness (2003 dollars): $4,823,925 / 21 = $229,710/ton. 

Incremental cost-effectiveness (2011 dollars): $229,710 x 1.22 = $280,246/ton 

EPA Region 8’s preliminary conclusion on Scenario #1: Replacement of the current small precalciner with a large pre-calciner, without SNCR being installed along with it, can be expected to 

achieve substantial NOx control, but very little additional NOx control as compared to the 

existing NOx control system, and at an extremely high incremental cost-effectiveness. 

 

CONTROL UPGRADE SCENARIO #2: REPLACE EXISTING NOX CONTROL 

SYSTEM WITH A NEW LARGE PRE-CALCINER AND SNCR

Calculation of cost and emission reduction for new large pre-calciner and SNCR, to replace 

current NOx control system: 

Total annual cost for urea injection form of SNCR: $755,192. 

Uncontrolled NOx emission rate: 1,360 tpy (equivalent to 3.6 lb/ton clinker) 

Estimated NOx reduction with SNCR: 50%. 

(ref: 2007 ACT Document, cited earlier) 

Annual cost of SNCR, scaled up from 2005 to 2011 dollars: 

$755,192 x 1.15 = $868,471. 

Annual cost of new large pre-calciner, scaled up from 2003 to 2011 dollars: 

$4,823,925 x 1.22 = $5,885,188. 

Total annual cost, in 2011 dollars: $868,471 + $5,885,188 = $6,753,659. 

 
Additional NOx reduction that might be achievable by SNCR, on the controlled emissions from a 

new large pre-calciner, at kiln capacity: 50% of 1,197 tpy = 598 tpy. 

Total NOx reduction that might be achievable with new large pre-calciner plus SNCR, at kiln 

capacity: 955 + 598 = 1,553 tpy. 

Incremental NOx reduction, versus current NOx control system, at kiln capacity: 

1,553 – 1,218 = 335 tpy. 

Total cost-effectiveness: $6,753,659 / 1,553 tons reduced = $4,348 per ton reduced. 

Incremental cost-effectiveness: $6,753,659 / 335 tons reduced = $20,160 per ton reduced. 

EPA Region 8’s preliminary conclusion on Scenario #2: Replacement of the current small precalciner with a large pre-calciner and SNCR can be expected to achieve substantially more NOx 

control than just a large pre-calciner alone, and is not extremely expensive (i.e., less than 

$5k/ton) in terms of total cost-effectiveness, but is much more expensive in terms of incremental 

cost-effectiveness (greater than $20k/ton), where current NOx controls are taken into 

consideration.