Document NezMXXzqo5qj1Bbg1gQxJDdOD

July 19, 1994 Mr. Don Watts Mississippi Department of Environmental Quality Office of Pollution Control P. O. Box 10385 Jackson, MS 39289-0385 RE: Determination of Potential To Emit HC1 From Vinyl Chloride Control Device Dear Mr. Watts: Vista Chemical Company is requesting a determination on calculation of "potential to emit" (PTE) hydrogen chloride (HC1) from a control device used to limit vinyl chloride monomer (VCM) emissions from process vents. Calculation of the PTE HC1 is necessary to determine the plant's status as a major or minor source under the Title V permitting program. Vista Chemical Company's Aberdeen Plant uses VCM to produce polyvinyl chloride (PVC) resins. The plant is subject to the National Emission Standards for Hazardous Air Pollutants (NESHAPs) contained in 40 CFR 61 Subpart F - National Emission Standard for Vinyl Chloride. The VCM NESHAP requires process vents containing VCM be ducted to a control device from which the concentration in the exhaust gases does not exceed 10 ppm (average for 3-hour period). Most plants subject to the VCM NESHAP, including the Aberdeen Plant, use an incinerator as the control device to limit VCM emissions. The incineration of VCM produces HC1. Most VCM incinerators, including the Aberdeen Plant's incinerators, are fitted with scrubbers to remove HC1 from the gas stream. The Aberdeen Plant uses the HC1 discharged in the scrubber effluent to neutralize high pH streams from other processes before these streams enter the wastewater treatment system. To demonstrate compliance with the 10 ppm emission standard, a gas chromatograph (GC) samples the exhaust gases from the scrubber. Removal of HC1 from the gas stream is necessary to prevent analyzer damage and allow the required monitoring of the VCM emissions. Title III (Hazardous Air Pollutants) of the Clean Air Act Amendments define major source as follows: "'major source' means any stationary source... that emits or has the potential to emit considering controls, in the aggregate, 10 tons per year or more..of any hazardous air pollutant." B0139913.DOC VAB.0001159558 Vista Cham!cal PTB Determination - Pag* 2 As a practical matter, HC1 must be removed before the exhaust gas is monitored with an on-line instrument. Based on the NESHAP requirement for a control device and monitoring of VGM in exhaust gases together with the definition of major source under Title III, Vista believes that PTE HC1 should be calculated aftar the scrubber. Please advise as to whether the Office of Pollution Control concurs with this calculation methodology. If you have any questions or require further information please call me at 369-3637. / Kenneth 6. Akins Senior Environmental Coordinator c: LLZ, JCL, JEN % B0139913.DOC VAB.0001159559