FROM: Jeff Coburn, RTI International

TO: Brenda Shine, EPA/OAQPS

FOR: Docket ID No. EPA-HQ-OAR-2003-0146

DATE: August 29, 2012

SUBJECT: Evaluation of the Refinery ICR Cooling Water Analysis Results

1. Purpose

This memorandum summarizes the results of th e cooling water sampling and analysis conducted in response to the detailed information collec tion request (ICR) for petroleum refineries.

2. Background

On April 1, 2011, the EPA sent an ICR to facilities in the U.S. petroleum refining industry. The ICR was comprehensive and designe d to collect information on pro cessing characteristics, crude slate characteristics, emissions inventories and so urce testing to bolster our current data and fill known data gaps. The ICR had four components: (1) a questionnaire on processes and controls to be completed by all petroleum refineries (C omponent 1); (2) an emissions inventory to be developed by all petroleum refine ries using the emissions estimati on protocol developed for this effort (Component 2); (3) distillation feed sampling and analysis to be conducted by all petroleum refineries (Component 3); and (4) em issions source testing to be completed in accordance with an EPA-approved protocol for speci fic sources at specific petroleum refineries (Component 4).

Component 4 of the ICR required so urce testing for twelve different types of emission sources or units; one of the types of sources for which testing was required is cooling water systems (also known as heat exchange systems). Owners or oper ators of cooling water systems at 11 selected facilities were required to te st for total strippable volatile organic compounds (VOC) using Modified El Paso Method (TCEQ, 2003). Following Modified El Paso testing, additional testing was performed on the cooling water system w ith the highest total strippable hydrocarbon concentration, except for the following situations: (1) if more than one cooling water system return line had total strippable hydrocarbon conc entration greater than 62 parts per million by volume (ppmv), then the facility conducted additio nal testing for all cooling water systems that had a return line concentration gr eater than 62 ppmv; a nd (2) if none of the cooling water system return lines had a total strippa ble hydrocarbon concentration greate r than or equal to 3 ppmv, then the facility conducted additional testing only for hydrogen chloride (HCl) and chlorine (Cl 2 ) for any one cooling water system return line.Technical Memorandum – Evaluation of the Re finery ICR Cooling Water Analysis Results August 29, 2012

2 The additional testing included:

 Speciated volatile organic hazardous air po llutants (HAP) (in stri pping air and water)

 Speciated semi-volatile organic HAP (in stripping air and water)

 Formaldehyde (in stripping air)

 Total hydrocarbons (in stripping air)

 Methane (in stripping air)

 Hydrogen chloride and chlori ne (in stripping air).

3. Summary of Results

Four of the 11 facilities that we re required to test their coolin g water systems did not have any strippable hydrocarbons in the cooling water atconcentrations of 3 ppmv or greater (as methane), so these four facilities did not do additional organic sampling and analysis. Three small refineries did not conduct on-site flame ioni zation detector (FID) analysis using the direct Modified El Paso Method, but c onducted detailed sampling on a se lect cooling water system or each cooling water system at the facility. In total, seven refine ries conducted detailed sampling of eight cooling water systems. The potential emissions in pounds per da y (lb/day) associated with the hydrocarbons measured in the cooling water were calculated based on the water-phase concentrations and the water flow rate of the c ooling water system. Concentrations determined in the stripping air were back-calculated to wate r-phase concentrations us ing Equation 7-1 of the Modified El Paso Method (TCEQ, 2003). The projected emissions from the speciated analyses were calculated by summing the emissions projecte d for each compound detected in at least one sample analysis for a given cooling water system . Concentrations of compounds detected below the lowest calibration standard (commonly marked in the analytical reports with a “J”) were used as reported; concentrations for compounds that we re not detected in any samples were assumed to be zero. The calculated poten tial emissions from the ICR te sting data are summarized in Table 1 . A detailed summary of the specific analy tical results is available on the petroleum refinery sector ICR web page ( http://www.epa.gov/ttn/a tw/petref/petrefpg.html ) under the “ICR Component 4 – Emission Source Testing” section.

4. Discussion of Results

The results of the direct El Pa so on-site FID measurements compare well with the results of stripping gas collected for total hydrocarbon anal ysis or methane plus non-methane organic carbon (NMOC) analysis. For one cooling water system (Facility ID LA3C0700; Cooling Water System 8006), the results of the laboratory analys is of the collected gas is about a factor of 3 greater than the direct El Paso FID reading. This may be due to an error in labeling the results. The NMOC were labeled “as propane” so the ca lculated water concentrations (and potential emissions) are approximately 3 times greater than if these results were actually measured “as methane.” The El Paso FID readings were not sp ecifically marked, so they were assumed to be “as methane.” If these measurements were made on the same basis (either both “as methane” or both “as propane”) then the calculated emissions would have been more similar for the two sets of results.Technical Memorandum – Evaluation of the Re finery ICR Cooling Water Analysis Results August 29, 2012

3 The results of the speciated stripping air sample analyses were always much less than the total hydrocarbon analyses. The results of the speciate d water sample analyses were also much less than the total hydrocarbon analyses, as a general rule. There were several water samples whose analyses appeared to be contamin ated with acetone and/or methyl ene chloride (see footnotes to Table 1 for details). Excluding these analytes, the sp eciated water sample analytical results were generally comparable to or less than the speciated air sample an alytical results. The largest discrepancy for the air versus water speciation results (not consideri ng the probable acetone contamination) were for Facility ID LA3C0700; Cooling Water System 8006. This cooling water system had significant total hydrocar bon and speciated HAP emissions based on the analysis of the stripping air, but all analytes were below detection limit for the water samples.

Table 1. Summary of Cooling Water System ICR Anal ytical Results

Facility ID/Cooling Water System ID Estimated Hydrocarbon Emissions (lb/day) based on:

El Paso On-site FID Methane+NMOC Method 18/TO-12 Sum Analytes in Gas; TO-11/15 Sum Analytes in Water M8260B/8270C
CO4A0340/P2CT-1 16.3 17.9 5.85 BDL a LA3C0700/8006 867 3,880 b 111 BDL a
NM3E0880/CT-1&2 354 83 107 OK2C0960/Hydrocrkr 82.8 12 112 c
PA1B150/West 6.5 4.3 0.35 0.38 UT4A1380/11 1,100 1,160 0.87 2.43 d

WI2B1460/CT1 1.47 0.02 23.8 d

WI2B1460/CT2 2.4 0.22 BDL a

a All analytes were below the analytical detection limit (BDL).

b NMOC concentration value was reported “as propane.” If th is was actually “as methane” the calculated emissions would be similar to those determined using the El Paso me thod (they did not s pecify if the El Paso concentrations were FID “as methane” or “as propane,” but were assumed to be “as methane”).

c One water sample had high acetone conc entration; the next two were detected but below quantitation limit (roughly a factor of 10 lower concentration). Excluding this one high acetone sample (but using the average of the other two acetone concentrations), the emission s would be estimated as 35 lb/day. The next highest detected quantity was for methylene chloride, which was also detected in the blan k. The refinery notes that both acetone and methylene chloride are not expected to be in any of the streams serv iced by the cooling tower and are expected to be laboratory contaminants. Little to no acetone or methylene chloride we re present in air samples. Emissions based on the water method’s analytes excluding acetone a nd methylene chloride are 1.9 lb/day.

d The primary (or, for WI2B1460/CT1, the only) analyte det ected in the water sample was acetone. Little to no acetone was present in air samples. Again, ac etone appears to be a laboratory contaminant.

There are several reasons why the speciated an alyses yield lower results than the total hydrocarbon analysis. The primary reason for this is that the target lis t of analytes for the speciated analyses did not include all of the hydrocarbon compounds pr esent in the cooling water. The speciated target an alyte list included primarily HAP constituents and only a few nonHAP compounds. Many petroleum refinery hydrocar bons are not HAP, so the target analyte list, which focused on HAP, did not include all of the compounds that could have been present in the cooling water. Another reason why the speciated an alyses may have yielded lower results is thatTechnical Memorandum – Evaluation of the Re finery ICR Cooling Water Analysis Results August 29, 2012

4 many of the individual constituents were presen t below the analytical detection limit. Many refinery process streams may have hundreds of di fferent organic species. When the compounds are separated in a GC and indivi dual peaks are analyzed, the i ndividual peaks may be small and some may be so small that the peak is not de tected. However, when all these trace compounds are analyzed together (no GC separation), these compounds will add to the total hydrocarbon concentration measured by the detector.

Most analytical test methods provide a specific list of analyt es for the method. The list of analytes may not include all compounds poten tially determined by the method, but the method will generally list the most common compounds fo r which the method has been used and for which detection limits and other analytical parame ters have been assessed. Therefore, if a certain test method is specified and the target analyte list is limited to only those compounds specifically listed in the referenced test method, th en the speciated analyses will invariably have a similar low bias compared to the total hydro carbon analysis as seen in Table 1 for most petroleum refinery streams. Another way to say this is that unless the composition of the process stream consists of only one to a few compounds that are all included on the ta rget analyte list, the speciated analyses will result in lower overall concentr ation as compared to a total hydrocarbon measurement. As such, speciated analyses are less likely to identify a leak into the cooling water. For petroleum refineries, where the MA CT floor is based on total hydrocarbon analysis using the Modified El Paso Method, speciated analysis to identif y leaks at the same concentration action level used fo r the total hydrocarbon analyses is expected to be less stringent than the MACT floor.

The low bias of speciated analysis exists for bot h the stripping air analys is and the direct water analysis. The direct water analysis appears to be more limited by detection limits (that is, stripping air analysis appears to be more sensitive and capable of detecting trace quantities of volatiles in the cooling water). The direct wate r analysis also appears to be more prone to laboratory contamination. It appears that severa l of the water samples had trace quantities of acetone and/or methylene chloride that are more likely to have come from laboratory contamination than a leaking petroleum refinery heat exchanger. Volatile loss during water sampling has also been identified as a potential bias for the water analysis methods (TCEQ, 2003). Use of the Modified El Paso Method wi th on-site FID detection for total hydrocarbons (or off-site analysis of the stripping air for tota l hydrocarbons) eliminates the potential biases of the speciated methods and the ot her potential issues identified above concerning water sampling and analysis.

5. References

TCEQ (Texas Commission on Environmental Qual ity). 2003. “Air Stripping Method (Modified El Paso Method) for Determination of Volatile Organic Compound Emissions from Water Sources,” Revision Number One, Sampling Procedures Manual, Appendix P: Cooling Tower Monitoring . January.