1

MEMORANDUM

TO: Toni Jones, U.S. Environmental Protection Agency

FROM: Eastern Research Group, Inc.

DATE: December 12, 2014
SUBJECT: Potential Emission Limits Calculation Analyses for Waste-burning Kilns and

Coal ERUs

B ACKGROUND On February 7, 2013, the Environmental Protection Agency (EPA) prom ulgated its final response to petitions for reconsideration of the final new source per formance standards and emission guidelines for commercial and industrial solid waste incine ration units that were promulgated on March 21, 2011. Following promulgation of the February 2013 final ac tion, the Administrator received petitions for reconsideration that identified is sues that petitioners maintain require additional reconsideration and/or warrant further opportunit y for public comment. EPA granted reconsideration of, and requested comment on , the following issues raised: 1) Definition of “CEMS data during startup and shutdown periods; ” 2) particulate matter (PM) limit for the waste-burning kiln subcategory; 3) fuel variability fa ctor for coal-burning energy recovery units (ERUs); and 4) the definition of kiln.

The purpose of this memorandum is to summarize additional data received since the 2013 final rule and to present the emission limits that would result if EPA employed the Petitioners’ suggested approaches for resolving issues (2) and (3). This m emo is organized as follows:

I. PM Emission Limits for Waste-Burning Kilns II. Coal-burning ERU Fuel Variability Incorporation

a. Incorporating Coal-Only Data b. Determining Fuel Variability Factors

c. Potential Limits for Coal-Burning ERUs III. List of Appendices

I. PM E MISSION L IMITS FOR W ASTE -B URNING K ILNS Between the March 2011 final rule and the February 2013 final rul e, the inventory of cement kilns burning solid waste (i.e. subject to CISWI) fluctuated based on revisions made to the NHSM rule. EPA used the same calculation methodology (i.e., the upper prediction limit (UPL) calculated from a population of individual test runs) with eac h iteration of the corresponding emissions data. One petitioner argued, however, that the fi nal data set is large enough to warrant using 3-run emission test averages as the data population, r ather than individual test runs. According to the commenter, using this approach to calculate emission limits would result in PM emission limits that are different than those of the Fe bruary 2013 CISWI final rule.

The PM limit for existing kilns in the 2013 final rule is ba sed on 62 data points – individual runs from emissions tests conducted on the three best performi ng units. The raw data upon which the2

MACT analysis was based is included here as Appendix A. To develop the potential new PM limit for existing units, averages for each of these test s were calculated, yielding a total of 24 data points. The 99 percent UPL was calculated using the same equa tion used previously:



###    × 

### = ̅ +   
,   

### 

  

###  1

 + 1

 

Where:

α = the level of significance expressed as a decimal (0.01), note that 100-( α ×100) = the

confidence level (0.99, or 99%); = average or mean of test run data;

 = t score, the one-tailed t value of the Student’s t d istribution for a specific degree of freedom and level of significance;

n = the number of data points;

  = variance of test run data; and

 = number of test run values used to calculate the tes t average.

In this case, though, n represents the number of averages (24) rather than the num ber of test runs. For the 2013 final limit UPL calculations, m represented the number of observations that would be considered in the future for demonstrating compliance; becaus e stack tests generally consist of three individual test runs, m was set to equal 3. However, because test run averages are used as data points in this potential new approach, m is set equal to 1 in the UPL equation (i.e., there will be a single observation, the three-run test average, used in future demonstrations of compliance).

The UPL calculations are presented in the PM EG tab of A ppendix B. The same method was applied to develop the potential PM limit for new units, using 10 averages rather than 27 individual run values for the top performing unit. These ca lculations are presented in the PM NSPS tab of Appendix B. In both cases, the 99% UPL was rounded up to two significant figures. The resulting potential test average-based PM emission lim its are shown below and compared to previous proposed and promulgated limits.

New or Existing PM Limit (units) March 2011 Final Rule December 2011 Proposed Rule February

2013 Final Rule Test average

based calculated limits New Sources PM limit (mg/dscm) a 2.5 8.9 2.2 4.9

Existing Sources PM limit (mg/dscm) a 6.2 9.2 4.6 13.5

a Emission limits are expressed as concentrations corre cted to 7 percent oxygen.

II. C OAL

- BURNING ERU F UEL V ARIABILITY I NCORPORATION One petitioner advised EPA of concerns that the derivation of the CISWI limits should take into account the variable constituent levels in coal, urging t he EPA to incorporate fuel variability into the emission limit calculations for coal-fired ERUs as was done in the Boiler MACT. The petitioner contended that EPA’s emissions dataset for coal ERUs is very limited for the fueldependent pollutants HCl, Pb, Cd, Hg, and SO 2 , and that emission standards based on stack test and CEMS data alone are too stringent to be met reliably because of the inherent variability of the coal. Specifically, they noted that emission standards were based solely on one stack test for Cd,3

Pb, and HCl, two stack tests for Hg, and seven days o f CEMS data for SO 2 , emphasizing the short-term nature of these data. They argued that coal has variable levels of each of these contaminants, referencing historical fuel data previousl y submitted to the Agency during the public comment period.

The petitioner also contended that the data EPA has used t o establish the final rule NOx emission limit for the best-performing unit in the coal-fired ERU subcategory does not reflect this unit’s actual performance accurately, since it reflects only pe riods of waste combustion in the analysis. The petitioner noted that this unit, as well as the other coal-fired ERUs at this facility, operates for extended periods of time in a non-waste burning mode. As a remedy, the petitioner suggested that EPA use data from both waste-burning and non-waste burning periods for the bestperforming unit to establish MACT floor emission limits, s tating that this will more accurately reflect actual operating conditions for this unit.

In response to these concerns, we have conducted analyses to determine what the coal-burning emission limits would be if (1) emissions data for both waste and coal-only periods were incorporated into the UPL calculations, and (2) if fuel data were used to determine pollutantspecific fuel variability factors (FVFs) to incorporat e into the final emission limits. A summary of the resulting emission limits is presented in the table b elow:

Pollutant 99% UPL Fuel Variability Factor a (FVF) Emission Limit b

Feb 2013 (Coal-Only Emissions data excluded) Potential

(Coal-Only Emissions data incorporated) Feb 2013 Final (No FVF) Potential

(UPL*FVF)
Cadmium (Cd) (mg/dscm) 0.00946 0.00166 N/A 0.0095 0.0017 Hydrogen Chloride (HCl) (ppmv) 12.49 8.23 7 13 58 Mercury (Hg) (mg/dscm) 0.0160 0.0127 N/A 0.016 0.013 Lead (Pb) (mg/dscm) 0.1360 0.0394 1.43 0.14 0.057 Particulate Matter (filterable) (mg/dscm) 154 122 N/A 160 130 Nitrogen Oxides (NO x ) (ppmv) 331 450.46 N/A 340 460

a Unable to calculate FVF for Cd, Hg, PM, and NO x . FVFs for HCl and Pb are based on maximum ratio in data set for coal-only mode of operation. See discussion b elow for details.
b All emission limits are expressed as concentrations co rrected to 7 percent oxygen.

A. Incorporating Coal-Only Data

NO x Emissions Data

The NO x limit in the 2013 final rule is based on NOx CEMS data for Eastman Chemical Company’s Boiler 18. The data was from the company’s 2009 ICR respo nse. At the time of promulgation, it was the only NO x data in the CISWI database for coal-burning ERUs. Therefo re, by default, Boiler 18 was ranked as the best-performing unit for NO x . 1

Eastman explained in their petitions that their Boilers 18, 19, and 20 only burn solid waste during a small percentage of their operating hours. In order to m ore accurately represent operating

1 See November 2012 memorandum “CISWI Emission Limit Calculations for Existing and New Sources for the Reconsideration Final Rule” (DCN: EPA-HQ-OAR-2003-0119-2662)4

conditions for these units, they provided EPA with additional NO x CEMS data which characterized periods when only coal was combusted as wel l as periods when both coal and waste were being combusted. However, the data was for their B oiler 20, and when the NO x data averages were compared, Boiler 18 was still the best perfor mer (i.e. the NSPS and EG limits would still be based on the individual run data for Boiler 18).

Eastman indicated Boiler 20 data should be used in the UPL calculation because the unit is identical to Boiler 18 and the two units share the same s tack. EPA determined this was not appropriate, however, because the emissions were measured a t the ductwork from the individual units before the combined stack, and therefore the data ref lects the performance of the individual unit in particular. Eastman therefore submitted additional NO x data for Boiler 18 that includes periods of burning coal only from April 17-May 15, 2014.

The submitted supplemental petitions and NO x data for Boilers 20 and 18 are included as Appendices C and D, respectively.

Coal-Only Emissions Data for Other Pollutants The MACT floor calculations used at promulgation excluded emissions data collected during periods when no waste was being combusted. For the current eff ort, we revisited test reports for coal-burning ERUs to extract data that reflects periods w hen only coal was burned. The data include emissions concentrations for Cd, HCl, Hg, Pb, an d PM for Eastman’s Boilers 19 and 20. The additional data are presented in the Data Revisions ta b of Appendix E.

Ranking and Calculating 99% UPL Using the same methodology employed at promulgation and incorpor ating the additional data described above, EPA calculated the 99% UPL for Cd, HCl, H g, Pb, PM, and NOx for coalburning ERUs. Averages for each pollutant for each boiler we re calculated in the Data Revisions tab of Appendix E, and the units were ranked in the Rankings - ERU - Coal tab of Appendix E. In some cases, the best performing units changed. Corresponding UP L calculations are presented in Appendix F. Calculations are identical for new and existing u nits because only one unit represents the top 12% of existing units.

B. Determining Fuel Variability Factors FVFs were calculated using a methodology similar to that use d for the Boiler MACT. For a given pollutant, the following data is needed in order to determine a FVF:

1. Historical fuel data and fuel data corresponding to the emissions tests of the best performer(s) 2. Fuel data that corresponds to the best performers’ emiss ions test data During the comment period following the 2011 reconsideration propos al, Eastman provided EPA with historical fuel analysis data for sulfur, lead, m ercury, and chlorine, urging EPA to use the data to develop FVFs for SO2, lead, mercury, and hydrogen c hloride. 2 Eastman acknowledged that no cadmium was detected in Eastman’s fuel analys es, therefore no FVF could be determined for this pollutant fuel data.

In additional to the historical fuel data, fuel data speci fic to the emissions tests of the best performer for each pollutant (“paired data”) were ident ified and extracted from test reports. 3

2 Eastman Chemical Company February 14, 2012 comment letter (DCN: EPA-HQ-OAR-2003-0119-2569)

3 Blr 19 B-83 Stationary Source Sampling 12-14-05.pd f , Blr 19 B-83 Stationary Source Sampling 3-8 and 9-05.pdf, Blr 20 B-835

Because these are multiple-fuel boilers, data correspondin g to the predominant fuel (with respect to pollutant loading) for each pollutant was selected, an d the single highest concentration value for a given pollutant was compared to each historical dat a point using a ratio (the maximum value during the emissions testing being the denominator and each h istorical data point the numerator).

The next step in the analysis is to identify the historica l data points for which this ratio is greater than one (i.e. instances where the pollutant concentration in the fuel was higher than the pollutant concentration in the fuel during the emissions tests). Any of these ratios greater than or equal to the averages of all the ratios plus three standard deviation s of all the ratios were removed as outliers. The FVF could be calculated based either on the maximum of the remaining ratios or the mean of the remaining ratios. For the purposes of this an alysis, the maximum ratio was selected to develop a potential FVF.

FVF calculations and data sources are presented the indivi dual pollutant tabs of Appendix G. Based on available data, FVFs were calculated for two pollutants, HCl and Pb. No FVFs were determined for Hg, Cd, PM, NO x , or SO 2 for the following reasons:

Mercury . There were only two instances where the ratio of histor ical data to paired data was greater than one, and these two data points were ou tliers. Therefore, no FVF could be determined for mercury. Cadmium . As noted above, fuel data was all non-detect for this pol lutant. Particulate Matter. No paired or historical fuel data available. Nitrogen Oxides. No paired or historical fuel data available. Sulfur Dioxide . Although percent sulfur was included in the historical f uel data provided by Eastman, only one fuel data point was available to be pai red with SO2 emissions data. Eastman claimed they supplied 4 values for percent sulfur th at could be paired with 30 days of SO2 data they’d also submitted. However, that CE MS data corresponded to their coal-fired boilers, not the three CISWI units (Boilers 18, 19, and 20).Therefore, no FVF was determined.

C. Potential Limits for Coal-Burning ERUs The potential new limits for coal-burning ERUs were cal culated by multiplying the revised UPL values (discussed in II.A above) by the calculated FVFs ( discussed in II. B, above), where applicable. If no FVF was determined, the potential limi t is simply the UPL rounded up to the nearest two significant figures. Where FVFs were calcula ted, the product of the UPL and FVF is rounded up to the nearest two significant figures.

Revised 99% UPL values, FVFs, and all potential limits (including those if the FVF is based on an average ratio) are presented in the Summary tab of A ppendix G.

III. L IST OF A PPENDICES

Appendix A KilnEmissionsData.xlsx Appendix B Existing Kilns PM Variability With Run Averages.xls x Appendix C Eastman Boiler 20 NOx Data May-June 2013.xlsx Appendix D Eastman Boiler 18 NOx Data April-May 2014.xlsx Appendix E Rankings_IncludingCoal-OnlyData.xls Appendix F VariabilityAnalysis - ERU - Coal - IncludingCoa l-OnlyData.xls

Stationary Source Sampling Report 11-30 and 12-1-04 .pdf available within DCN EPA-HQ-OAR-2003-0119-004 7.6

Appendix G FVFCalcs.xlsx