{In Archive} FYI - EPA Letter Shaheerah Fateen to: Gerardo Rios, Ann Lyons 04/06/2004 11:01 AM Archive: This message is being viewed in an archive. fyi ----- Forwarded by Shaheerah Fateen/R9/USEPA/US on 04/06/2004 10:59 AM ----- Shaheerah Fateen 04/02/2004 02:02 PM To: neil.j.ryan@exxonmobil.com cc: Subject: EPA Letter Neil, attached is the letter I mentioned to you over the phone earlier this week. The purpose of the letter is to update the information in the Part 71 application for the McElmo Creek Unit. The letter was mailed today. Please let me know if you have any questions. Thanks.

Shaheerah Fateen U S EPA Region 9, Air Division (AIR-3) San Francisco, CA 94105 email: fateen.shaheerah@epa.gov Phone: 415-947-4156 Fax: 415-947-3579UNITED STATES ENVIRONMENTAL PROTECTION AGENCY REGION IX 75 Hawthorne Street San Francisco, CA 94105 March 31, 2004 Neil J. Ryan Regulatory Compliance Supervisor ExxonMobil Production Company U. S. Production P. O. Box 4358 Houston, Texas 77210-4358 Subject: Request For Information To Update Part 71 Permit Application No. NN-OP 00-07 Dear Mr. Ryan: The purpose of this letter is to request information in response to the Part 71 application, dated March 22, 2000, for the ExxonMobil McElmo Creek Unit (MCU) site. We are currently drafting the Part 71 (Title V) permit for this facility and reviewing the requirements that may apply to the source. Below is the information that will allow us determine the federal regulations that apply to MCU and complete the Part 71 permit for this site. We request that you provide us with responses by the date listed at the end of this letter.
1. Our records for this facility indicate one natural gas-fired turbine, which was used to drive natural gas compressors at the site, is located at MCU and that the turbine is subject to the performance standards for stationary gas turbines under 40 CFR Part 60 Subpart GG. Please identify the status of the gas turbine. Specifically, identify whether the emissions unit is currently operating at MCU or whether the unit is no longer operating and has been removed from the site. If the gas turbine is not operational, identify the date when the unit was permanently taken out of service.
2. Our records for this facility indicate that a natural gas liquids (NGL) plant was located on the MCU site. The records also indicate that the plant was subject to the requirements of 40 CFR Part 60 Subpart KKK, which is theperformance standards for equipment leaks of volatile organic compounds (VOC) from onshore natural gas processing plants. Please identify whether the NGL plant, and its associated equipment, is currently operating at MCU or whether the plant is no longer operating and has been dismantled and removed from the site. If the NGL plant is not operational, identify the date when the unit was permanently taken out of service.2

3. Our records indicate that MCU contained affected sources as defined under 40 CFR Part 60 Subpart LLL, which is the performance standards for sulfur dioxide emissions at onshore natural gas processing. The affected sources include a sweetening unit followed by a sulfur recovery unit. Please identify whether sweetening units and/or sulfur recovery units are currently operating at MCU, or whether the equipment are no longer operating and have been dismantled and removed from the site. If the equipment are not operational, identify the date when the units were permanently taken out of service.
4. The Part 71 application for ExxonMobil states that MCU is not subject to the maximum achievable control technology (MACT) standards under 40 CFR Part 63 Subpart HH, which applies to oil and natural gas production facilities. The March 22, 2000 Part 71 application states that according to GRI-GLYCalc calculations, the facility is not major for HAPs for the TEG reboiler. However, according to the GRI-GLYCalc attachment of an April 30, 1999 letter from Mobil Exploration & Producing U. S. Inc. to the EPA, uncontrolled emissions of n-hexane were estimated to be 12.2 tons per year, which exceeds the major source threshold of 10 tons per year for any single hazardous air pollutant and could potentially subject the glycol dehydrator and any other affected units to the Subpart HH MACT standard. The compliance deadline for the Subpart HH was June 17, 2002. At this time, any affected sources are required to comply with the requirements under the MACT standard. Please provide the following information in which our office will use to determine whether Subpart HH applies. (a) Identify each glycol dehydration unit, storage vessel with the potential for flash emissions, any ancillary equipment that are intended to operate in volatile hazardous air pollutant service as defined under § 63.761 and are located at the natural gas processing plant; and any compressors intended to operate in volatile hazardous air pollutant service as defined under § 63.761 and are located at the natural gas processing plant. (b) Describe the current operation any glycol dehydrators, storage vessel with the potential for flash emissions, any ancillary equipment that are intended to operate in volatile hazardous air pollutant service as defined under § 63.761 and are located at the natural gas processing plant; and any compressors intended to operate in volatile hazardous air pollutant service as defined under § 63.761 and are located at the natural gas processing plant. (c) Complete the analysis under § 63.760(a). To estimate the emissions, you may use the model GRI-GLYCalcTM version 3.0 or higher and the procedures presented in the associated GRI- GLYCalcTM Technical Reference Manual for estimating major HAP emissions from the TEG dehydrator.3

5. The prevention of significant deterioration (PSD) permit issued in 1991 contains enforceable requirements for the equipment listed in Attachment A. Of this equipment, only one TEG reboiler is listed in the Part 71 application. Aside from the equipment identified in items 1 through 4 of this letter and the one TEG reboiler identified in the Part 71 application, please confirm that the equipment listed in Attachment A and that are not listed in the Part 71 permit application have been dismantled and removed and are no longer operating at MCU. If the equipment are not operational, please identify the date when the emissions units were permanently taken out of service. If any of the equipment has not been removed, please inform us of the status of the equipment.
6. Please identify any of the following equipment that is located at MCU that either contains or contacts a fluid (liquid or gas) containing benzene: pumps, compressors, pressure relief devices, sampling connection systems, open-ended valves or lines, valves, connectors, surge control vessels, bottoms receivers, and control devices or systems which contacts benzene. Of the equipment identified, identify which equipment that either contains or contacts a fluid (liquid or gas) that is less than 10 percent by weight of benzene as determined using ASTM Method D-2267. (See 40 CFR 61.245(d).) We request that you submit this information by April 19, 2004 in order for us to determine whether the above federal regulations apply to MCU. If you need additional time please contact our office as soon as possible. The above information is necessary to complete the draft Part 71 permit for MCU. We appreciate your assistance and cooperation in providing this information. Please contact me at (415) 972-3974 or Shaheerah Fateen, of my staff, at (415) 947-4156 orfateen.shaheerah@epa.govif you have any questions or concerns. Sincerely, /Signed by Gerardo C. Rios/ Gerardo C. Rios Chief, Permits Office

Enclosure

cc: Jennifer Wilder Baird, ExxonMobil Production Company Irene T. Garcia, ExxonMobil Production Company Wilson Laughter, Navajo Nation Christopher Lee, Navajo Nation4 

### Attachment A Table 1 of Pollutant-Emitting Equipment Authorized Under the April 1991 EPA PSD permit for MCU

Emission Point Size Listed In Part 71 Application? T4500 Gas Turbine 4390 HP Not listed Ingersoll Rand Engine 491 HP Not listed Fairbanks Morse Engine 1712 HP Not listed Fairbanks Morse Engine 1712 HP Not listed Fairbanks Morse Engine 1848 HP Not listed Fairbanks Morse Engine 1848 HP Not listed DPC-540 470 HP Not identified in Part 71 application Waste Heat Recovery Unit 11.0 MMBtu/hr Not listed HC Liquid Reboiler 1.0 MMBtu/hr Not listed Heat Medium Heater 4.0 MMBtu/hr Not identified in Part 71 application TEG Reboiler 0.33 MMBtu/hr Listed as TEG Reboiler TEG Reboiler 0.33 MMBtu/hr Not listed TEG Reboiler 0.33 MMBtu/hr Not listed