Document x5qqe7ymo8XR3VO5BL8JmNVNy

Lake Charles VCM Plant CERTIFIED MAIL =8090866 RETURN RECEIPT REQUESTED June 18, 1982 Conoco Chemicals Company A Division of Conoco Inc. P O Box 605 Westlake. Louisiana 70669 (318) 481-5211 C 0-^.5 Al'-C. t> W v/ Ms. Adlene Harrison, Regional Administrator U.S. Environmental Protection Agency Region VI 1201 Elm Street Dallas, TX 75270 Dear Ms. Harrison: The following is a reoort of a relief valve discharge to the atmosphere at the Conoco 7CM Plant in Westlake, Louisiana which occurred on June 9, 1982. Reporting of the relief valve discharge is required under Section 61.65(a) of the National Emission Standard for Hazardous Air Pollutants for vinyl chloride At 10:50 pm on June 9, the relief valve on top of the Caustic Decanter relieved due to an overpressure.condition in a downstream Vinyl Check Tank. The Vinyl Chloride Monomer (VCM) was released into the relief vent line near the Caustic Decanter, but a closed valve on the line prevented the VCM from entering the main relief vent header. The line pressured up to 115 psig, equal to the pressure inside the Caustic Decanter. This high pressure caused the bellows on the Caustic Decanter relief valve to rupture, and 885 Lbs. of VCM were released to the atmosphere. The amount of VCM released was based on the assumption that the entire line between the Caustic Decanter and the closed valve filled with liquid, the high pressure ruptured the relief valve bellows, and the entire pipe volume was discharged to the atmosphere. The relief valve is a 3"x4" Consolidated Type 1905-30LC relief valve with a set pressure of 115 psig. The high pressure situation at the Vinyl Check Tank was corrected by switch ing to another Vinyl Check Tank. This was done as soon as the problem was discovered. The valve on the relief vent line which was closed appeared to be open from the position of the valve handle. The valve was installed the previous week during a plant shutdown, and the valve handle was improperly installed. The handle has now been properly installed. Our letters of August 30, 1981 and November 18, 1981 had stated that engineering design ChannP^-e^-irhff-Caijr,t:i-C. , nprantor-'-s--inol i-awing ryctpm wort* frfpng qtndipr[ to contain future releases of VCM from this system. The design for those Ms. Adlene Harrison Page 2 changes has been issued and tie-ins have been completed. The remainder bf-tfae-Dcoifictwill be installed in the near future. Installation of this project will successfully contain releases of this type." Please let me know if you have any questions concerning this report or if you require any additional information. Sincerely, Plant Manager Conoco VCM Plant br cc: Gus VonBoduncen - DNR Joe Withers - DNR bcc: CRH-MGH-BIR-JWW-RB-PLF-DLD-JCL-SWS CC, oooozi^9