Document g2weyEJDqok3JoL9728ZLgYXQ

Vista Chemical Company Lake Charles VCM Plant VCM Plant Rd, P.O. Box 605 CERTIFIED MAIL # 241 411 272 RETURN RECEIPT REQUESTED Westlake, Louisiana 70669 Phone (318)494-5000 October 24, 1986 VIST/ William H. Davis Department of Environmental Air Quality Division P O Box 44066 Baton Rouge, LA 70804 Quality Dear Mr. Davis: Attached is the additional information letter of October 8, 1986 concerning release on September 15, 1986. requested in your a vinyl chloride If you have any further questions, please contact George Hopkins, Chief Process Engineer, at (318) 494-5062. Sincerely, R. A. Conrad Plant Manager br bcc: JAD PEM MLA SCR GEH WPS BED MGH ERT JCL WLM RDH GJF HJN (Conoco) Question 1) Detail the event of finding the hole in the feed line. Who found it? How was it found? How can anyone be sure that the supply valve (from your sketch) was closed within one minute of the leak occurrence? Supply a copy of the operator's log and shift log that details this event. Answer 1) Two operators were working in the immediate vicinity of C-203, the Vinyl Column, and at approximately 0335 hours noticed liquid dripping from the insulation on the feed line to the column. One of the operators immediately rushed to the supply valve (a distance of about 100 feet) and closed it. He estimated that he had the valve closed within oneminute after the discovery of the leak. The belief that the leak had just started is supported both by the initially observed small leakage rate (whichincreased when the nitrogen purge was begun) and bythe fact that the presence of vinyl chloride wasn't detected by the fixed point monitor system until its next sampling of that area at 0341 hours(see attached Fixed Point Monitor Report). We have attached copies of the log sheets as requested. Most of the details described above were obtained from discussions with the operators within 1.5 days after the leak occurred. Question 2a) Detail the calculations atmosphere. for VCM emissions to the Answer 2a) Since the hole in the feed line was covered by an approximately 1-inch thick layer of stainless steel-wrapped insulation it was not possible to estimate the amount of leakage from the size of the hole in the pipe. Therefore the best estimate of the amount of liquid vinyl chloride was obtained from the observed leakage rate as reported by the operators. From their description an approximate volumetric flow rate was obtained in measurements performed in the lab. The estimated flow rate was used along with the density of vinyl chloride and the estimated liquid CWH 00000b977 leakage time to obtain the estimate of the amount of liquid vinyl chloride which leaked out in the time period between the time of the leak discovery and the cessation of liquid leakage (about 4 minutes). The amount obtained was about 19 pounds of vinyl chloride. This value includes the dripping loss as well as the loss during the nitrogen purging process. The amount of vinyl chloride vapor which may have been released after the nitrogen purging was completed was estimated by assuming that the entire volume of the feed line system (including H-212) was filled with nitrogen saturated with vinyl chloride at 80 degrees Fahrenheit and 100 psig and that all of this vinyl chloride was released to the atmosphere. This gave an estimated 73 pounds of vinyl chloride vapor which may have been released after the feed line was blocked in. The total amount of vinyl chloride which may have been released was therefore estimated to be about 92 pounds. Question 2b) Was there a picture taken documenting the size of the hole? Answer 2b) Yes, a picture was taken of the hole and is upon request. available Question 2c) From your verbage and sketch the supply valve was closed within 1 minute after the leak occurred and that only 19 pounds of vinyl was lost. Isn't it true that the line from the supply valve to C-203 through H-212 was full of vinyl? If nitrogen at 100 psig was opened into this feed line would it not push liquid through H-212 toward C-203 and out the hole? Answer 2c) Yes, the line from the supply valve to C-203 through H-212 was full of vinyl. When the leak was first detected there was only a dripping leakage rate. This increased to a "pencil stream" leakage rate during the approximately first 3 minutes of the nitrogen purging process, after which there was no visible liquid vinyl chloride leakage. All of the liquid leakage is included in the estimated 19 pounds of liquid vinyl chloride which was released. CUH OOOOOt 973 Question 3) For a better definition of the event and to enhance our understanding, is the current writeup simplified as the flow diagram? For example, was an operator taking readings on C-203 at 0330 hrs. and saw the hole appear in the line? Reporting this event by radio to the control room, the operator immediately blocked in the supply valve, opened the valve that bypasses the Feed Preheater, H-212 and blocked in the outlet and inlet valve of the preheater? This type of action would have minimized liquid vinyl to C-203. We can assume any number of things that may have happened, but we don't know actual events unless you tell us. Answer 3) Yes, the writeup was simplified, covering only the major parts of the event. Most of the details have been presented in the previous answers. Following is a step-by-step presentation of the events: a) Two operators were working on the east Vinyl Column reboiler when they discovered liquid vinyl chloride dripping from the insulation on the feed line to the column at approximately 0335 hours. b) One of the operators immediately rushed to the supply valve (about 100 feet away) and closed it. c) He then purged the line with nitrogen for about 4 minutes through H-212 into C-203, at which time the other operator closed the block valve at C-203. d) The outlet valve on H-212 was then closed, thus blocking in the section containing the leak. e) Water sprays, from the plant's firewater system were then placed on the leaking area to suppress any vinyl chloride vapors. f) Beginning at 0700 hours the feed line was further cleared and blinded at H-212, the bypass valve, and at C-203 and removed for replacement. ooooos*?79 CVJH 00:00:41 9-- 16-- B6 FIXED FOINT MONITOR REPORT FOR 9- 15-- B6 NUMBER OF LEAKS DURING THE PAST 24 HOURS: AREA 1 AREA n < CAR--171,PT3 1,2,3) = (CAR-171, RTS 1,4) - 2 LEAKS 4 1 LEAKS ^ AREA 3 (CAR-171.PTS 4,9) = 0 LEAKS AREA 4 (CAR-171.RTS 1,5) = 0 LEAKS AREA 5 (CAR-171,FT 6) = 0 LEAKS AREA 6 (CAR-171.PT 7) = 0 LEAKS AREA 7 (CAR-171,PT 0) = 0 LEAKS AREA 0 (CAR--171,FT 10) = " 0 LEAKS AREA 9 (CAR-401,PT 1) = 0 LEAKS AREA 10 (CAR-401.PT 2) 0 LEAKS AREA 1 1 (CAR-401,PTS 3,4,5.8) = 0 LEAKS AREA 12 (CAR-401.PT 6> = 0 LEAKS AREA 13 (CAR-401,FT 7) = 0 LEAKS AREA 14 (CAR-401,PTS 9,10) = 0 LEAKS A LEAK CCCURED AT A LEAK OCCURED AT A LEAK OCCURED AT 03:41!27 03:51:22 04:01:25 IN AREA IN AREA IN AREA .1 1 * 2X Nc4-Q ` fl^eAS I o. >"> di 2. o.r-e 4-^ e F / X e cl Po f n 4 Conifer rQ S O. r~ Q u r-\ q\ C - 3 3 , T I a^s i^d.KA^ci af 3 S' I a. ^ O H O { hours are acfnally' i-K e f e S' / cl ^ s I y i k\ y [ cK/tJr/ide -f-rov, e leak- Lj ^ 111\ V45 -P |V 5* -f c1 e4 e c + e_ a -f 03^/1 >990 ,00' CUV^ To VISTA From Calculation Sheet rti P- n> ~n o lST t P. 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