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1 A BATCH POLYSTYRENE REACTOR RUNAWAY: A CASE HISTORY BY RONALD J. WILLEY, PhD. PE. NORTHEASTERN UNIVERSITY PREPARED FOR SACHE A PRODUCT OF THE CCPS-AICHE.

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Presentation on theme: "1 A BATCH POLYSTYRENE REACTOR RUNAWAY: A CASE HISTORY BY RONALD J. WILLEY, PhD. PE. NORTHEASTERN UNIVERSITY PREPARED FOR SACHE A PRODUCT OF THE CCPS-AICHE."— Presentation transcript:

1 1 A BATCH POLYSTYRENE REACTOR RUNAWAY: A CASE HISTORY BY RONALD J. WILLEY, PhD. PE. NORTHEASTERN UNIVERSITY PREPARED FOR SACHE A PRODUCT OF THE CCPS-AICHE NEW YORK, NEW YORK 2000

2 2 PROVINCE OF QUEBEC CANADA ISLE OF MONTREAL LASALLE LACHINE CANAL ST. LAWRENCE RIVER

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7 7 THE ACCIDENT OCTOBER 13, 1966 LATE EVENING INITIAL EVENT STYRENE VAPOR COMBUSTION

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17 17 BACKGROUND

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19 19 5 POLYMERIZATION REACTORS IN THE BUILDING 2 REACTORS WERE USED FOR THE PROCESS DESCRIBED BELOW

20 20 PHYSICAL PROPERTIES OF STYRENE · MOLECULAR WEIGHT · BOILING POINT145 C · FREEZING POINT-30.6 C · FLASH POINT31 C · AUTOIGNITION TEMPERATURE 490 C CH=CH 2

21 21 ADDITIONAL PROPERTIES OF STYRENE FLAMMABLE LIMITS IN AIR (VOL%) 1.1 TO 6.1 OSHA PEL50 PPM WILL POLYMERIZE AT ROOM TEMPERATURE IF UNINHIBITED HEAT OF POLYMERIZATION74.5 MJ/KMOL C P, HEAT CAPACITY1.69 J/G

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23 23 ARRHENIUS EQUATION kRate constant APre-exponential constant E a Activation energy RGas Constant TAbsolute temperature

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25 25 EQUATIONS TO PREDICT TIME, t, TO RUNAWAY a is a proportionality constant T 1 is the initial temperature

26 26 ADIABATIC TEMPERATURE RISE OF CATALYZED STYRENE (HYPOTHETICAL EXAMPLE) from Boyle BATCH TEMPERATURE, o C TIME, t, MINUTES At ~130 o C, 10 MIN TO RUNAWAY

27 27 STYRENE POLYMERIZATION METHODS ANIONIC POLYMERIZATION CATIONIC POLYMERIZATION FREE RADICAL POLYMERIZATION ZIEGLER NATTA POLYMERIZATION

28 28 FREE RADICAL POLYMERIZATION CH=CH 2 + R. CH-CH R 2. INITIATION PROPAGATION R. CH-CH R 2.. n +

29 29 STYRENE TO POLYSTYRENE BATCH PROCESS 1. LOAD THE REACTOR WITH STYRENE 2. ADD POLYMERIZATION CATALYST 3. HEAT TO 95°C 4. HOLD FOR 2 TO 8 HOURS

30 30 STYRENE TO POLYSTYRENE BATCH PROCESS CONTINUED 5. TRANSFER TO FORMING UNIT AT ABOUT 75% CONVERSION 6. OPEN FORMING UNIT AFTER FULL CONVERSION. REMOVE PS BLOCK 7. CRUSH PS BLOCK 8. TRANSFER SOLIDS TO EXTRUDER

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34 34 THE RELIEF SYSTEM RUPTURE DISC SIGHT GLASS TO ROOF REACTOR INSIDE BUILDING OUTSIDE BUILDING

35 35 TIME LINE EARLY IN THE DAY OF EXPLOSION TIMENOTE 2:30POLYMER A PRODUCED 19:30STARTED POLYMER B BATCH 19:30LOADED MATERIAL 19:40STARTED HEATING 21:15HEATED TO 92°C

36 36 TIME LINE BEFORE EXPLOSION TIMETEMP,C NOTE 21: :45110 R.O. (REACTOR OPER.) IN CANTEEN 21: : :00126 R.O. RETURNED FROM CANTEEN

37 37 TIME LINE MINUTES BEFORE EXPLOSION TIMETEMP,CNOTE 22:02130 R.O. CHECKS IN 22:03132 R.O. ORDERS DUMP 22: MEN ATTEMPT DUMP 22:07170 R.O. ORDERS 3 BOLTS ON FLANGE 22:08 R.O. ORDERS EVACUATION

38 38

39 39 ?? HOW DID STYRENE FOG ENTER THE INTERNAL BUILDING ??

40 40 INVESTIGATION COMPARISON/CONTRAST OF TWO REACTORS ITEMREACTOR 1 REACTOR 2 (THE OTHER)(THE SUSPECT) RUPTURE DISCINTACTRUPTURED MANWAYINTACTINTACT DUMP VALVECLOSED1/4 OPEN SIGHT GLASSINTACTMISSING ANSWER: FAILED SIGHT GLASS

41 41 Courtesy Prof. Chuck Sheppard, Univ. of Tulsa

42 42 A CONFINED SPACE EXPLOSION

43 43 EXTENT OF EXPLOSION 11 PEOPLE KILLED 130 TON CAR OF VINYL CHLORIDE TIPPED OVER GUARDHOUSE DESTROYED BRICKS FOUND 400 FEET AWAY

44 44 TNT EQUIVALENT BASED ON THE ESTIMATED OVERPRESSURES AND AMOUNT OF STYRENE RELEASED BEFORE THE INITIAL COMBUSTION THE COMBUSTION WAS AS IF 6.6 TONS OF TNT EXPLODED AT ONCE

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46 46 FIRE PROTECTION SYSTEMS SPRINKLER SYSTEMS FIRE WATER PUMPS FIRE RATED WALLS AND BARRIERS

47 47 BROKEN SPRINKLER MAIN REMAINS OF POLYMERIZATION BUILDING

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49 49 PROPERTY DAMAGE SUMMARY POLYSTYRENE BUILDING DESTROYED BUILDINGS 1,4,5,8,&12 SUFFERED FIRE AND WATER DAMAGE PUMP HOUSE DESTROYED SEVERAL AUTOMOBILES DAMAGED

50 50 INVESTIGATION SEARCH FOR THE ROOT CAUSE PRINCIPAL CAUSE – RUNAWAY REACTION CAUSED A PRESSURE BUILDUP INSIDE A REACTOR THAT SUBSEQUENTLY RELIEVED. ALL MATERIAL RELIEVED SHOULD HAVE EXITED BUILDING THROUGH ROOF VENT.

51 51 TESTIMONY STYRENE VAPOR INSIDE PS BUILDING WHY? FAILED SIGHT GLASS ABOVE RUPTURE DISK

52 52 POSSIBLE IGNITION SOURCE ARCING MOTOR? HOT SURFACES? ELECTROSTATIC DISCHARGE?

53 53 WHY DID THE REACTION RUN AWAY? WRONG CAM ON THE RECORDER? OR THE PENS STUCK?

54 54 LESSONS LEARNED MAINTAIN CRITICAL PROCESS EQUIPMENT INSTALL AUDIBLE ALARMS CENTRALIZE CONTROL OF BATCH OPERATIONS ELIMINATE SIGHT GLASS VIEWPORTS FROM RELIEF LINES HAVE SEMI-AUTOMATED DISCHARGE SYSTEMS (REMOTE DUMP VALVE)

55 55 BROADER LESSONS LEARNED USE DOW FIRE AND EXPLOSION INDEX FOR SPACING OF PROCESS EQUIPMENT STORAGE TANKS, AND TANK CAR KEEP UPDATED DISASTER CONTROL PLANS

56 56 OTHER LESSONS LEARNED REDUNDANT PROCESS CONTROL EQUIPMENT LOCATION OF EMERGENCY POWER AND FIRE PROTECTION FAIL SAFE VALVES ON STORAGE TANKS

57 57 ACKNOWLEDGEMENT DR. WALT HOWARD LASALLE FIRE DEPARTMENT MR. ROBERT GUERARD MR. JOHN PAUL LACOURSIERE SACHE COMMITTEE


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