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
Mar 31, 2015
1
A BATCH POLYSTYRENE REACTOR RUNAWAY:
A CASE HISTORYBY
RONALD J. WILLEY, PhD. PE.NORTHEASTERN UNIVERSITY
PREPARED FOR SACHEA PRODUCT OF THE CCPS-AICHE
NEW YORK, NEW YORK 2000
2
PROVINCE OF QUEBECCANADA
ISLE OF MONTREAL
LASALLE
LACHINECANAL
ST. LAWRENCE RIVER
3
4
5
6
BUILDING #2 POLYSTYRENE
7
THE ACCIDENT
OCTOBER 13, 1966
LATE EVENING
INITIAL EVENT
STYRENE VAPOR COMBUSTION
8
9
10
11
12
13
14
15
16
17
BACKGROUND
18
ST. PATRICK STREET
SUBSTATION
SUBSTATION
21MFGUNIT
19MFGBLDG
22MFG UNIT
11STORAGE
12MAIN OFFICE
25MFGBLDG
20WASTE TREATMENT
PLANT
12RESEARCHBLDG
GUARDHOUSE
GARAGE10
2POLYSTYRENE
PUMPHOUSE
STORAGETANKS
3STORAGE
8SERVICES
BLDG
6STEAMPLANT
5MFG BLDG
4MFG BLDG
PLANTNORTH
MERSIZETANKS
SITEOF
ACCIDENT
RAILROADTRACKS
RAILROADTRACKS
100 FT
7MFGBLDG
19
5POLYMERIZATION REACTORS
IN THE BUILDING
2 REACTORS WERE USED FOR THE PROCESS DESCRIBED
BELOW
20
PHYSICAL PROPERTIES OF STYRENE
· MOLECULAR WEIGHT 104.5· BOILING POINT 145C· FREEZING POINT -30.6C· FLASH POINT 31C· AUTOIGNITION TEMPERATURE 490C
CH=CH2
21
ADDITIONAL PROPERTIES OF STYRENE
FLAMMABLE LIMITS IN AIR (VOL%) 1.1 TO 6.1OSHA PEL 50 PPMWILL POLYMERIZE AT ROOM TEMPERATURE IF UNINHIBITEDHEAT OF POLYMERIZATION 74.5 MJ/KMOLCP, HEAT CAPACITY 1.69 J/G
22
Vapor Pressure - Temperature for Styrene and Water
0
10
20
30
40
50
60
70
80
30 40 50 60 70 80 90 100 110 120 130 140 150
Temperature (ºC)
Pre
ssu
re (
psi
a) waterstyrene
23
ARRHENIUS EQUATION
k Rate constantA Pre-exponential constantEa Activation energyR Gas ConstantT Absolute temperature
RT
EexpAk a
24
RUNAWAY REACTIONS
0
200
400
600
800
1000
1200
1400
1600
1800
0 50 100 150 200
TEMPERATURE,°C
RA
TE
OF
HE
AT
RE
MO
VE
D O
R
AD
DE
D
HEAT GENERATED BY EXOTHERMIC REACTION
MAXIMUM HEAT REMOVED BY HEAT TRANSFER
POINT OF NO RETURN
25
EQUATIONS TO PREDICT TIME, t, TO RUNAWAY
a is a proportionality constant
T1 is the initial temperature
12 aTexpKt
)c(contents)of(mass
reaction)ofheatreactant)( (massK
p2
26
ADIABATIC TEMPERATURE RISE OF CATALYZED STYRENE (HYPOTHETICAL EXAMPLE) from Boyle
0.1
1
10
100
100 150 200
BATCH TEMPERATURE, oC
TIM
E,
t, M
INU
TE
S
At ~130oC, 10 MIN TO RUNAWAY
27
STYRENE POLYMERIZATION METHODS
ANIONIC POLYMERIZATIONCATIONIC POLYMERIZATION
FREE RADICAL POLYMERIZATIONZIEGLER NATTA POLYMERIZATION
28
FREE RADICAL POLYMERIZATION
CH=CH2
+ R .
CH-CH R2
.INITIATION
PROPAGATION
R.
CH-CH R2
.
.
n
+
29
STYRENE TO POLYSTYRENE BATCH PROCESS
1. LOAD THE REACTOR WITH STYRENE2. ADD POLYMERIZATION CATALYST3. HEAT TO 95°C4. HOLD FOR 2 TO 8 HOURS
30
STYRENE TO POLYSTYRENE BATCH PROCESS CONTINUED
5. TRANSFER TO FORMING UNIT AT ABOUT 75% CONVERSION6. OPEN FORMING UNIT AFTER FULL CONVERSION. REMOVE PS BLOCK7. CRUSH PS BLOCK8. TRANSFER SOLIDS TO EXTRUDER
31
32
SIMPLIFIED SCHEMATIC FOR TEMPERATURE CONTROL ON JACKETED VESSELS
WATER FOR
COOLING
STEAM FOR HEATING
JACKET
Temperature TC
BATCH REACTOR
TO DRAIN
TC sensor
Air to Open
sensor
Air to Close
33
BatchPolystyreneReactor Train
StyreneStorage
TankGravity Feed
2400 gallon Batch Reactor
Forming Unit
Grinder
6" Dump Line toCatch Tank
Valve
BlankFlange
RuptureDisk
SightGlass
To Roof
2nd floor
1st floorReactorJacket
34
THE RELIEF SYSTEM
RUPTUREDISC
SIGHTGLASS
TOROOF
REACTOR INSIDE BUILDING
OUTSIDE
BUILDING
35
TIME LINE EARLY IN THE DAY OF EXPLOSION
TIME NOTE2:30 POLYMER A PRODUCED19:30 STARTED POLYMER B BATCH19:30 LOADED MATERIAL19:40 STARTED HEATING21:15 HEATED TO 92°C
36
TIME LINE BEFORE EXPLOSION
TIME TEMP,C NOTE21:15 9221:45 110 R.O. (REACTOR OPER.) IN CANTEEN21:51 11521:55 11922:00 126 R.O. RETURNED FROM CANTEEN
37
TIME LINE MINUTES BEFORE EXPLOSIONTIME TEMP,C NOTE22:02 130 R.O. CHECKS IN22:03 132 R.O. ORDERS DUMP22:04 137 3 MEN ATTEMPT DUMP22:07 170 R.O. ORDERS 3 BOLTS ON FLANGE22:08 R.O. ORDERS EVACUATION
38
39
??HOW DID STYRENE FOG ENTER
THE INTERNAL BUILDING??
40
INVESTIGATIONCOMPARISON/CONTRAST OF
TWO REACTORS
ITEM REACTOR 1 REACTOR 2
(THE OTHER) (THE SUSPECT)
RUPTURE DISC INTACT RUPTUREDMANWAY INTACT INTACTDUMP VALVE CLOSED 1/4 OPENSIGHT GLASS INTACT MISSINGANSWER: FAILED SIGHT GLASS
41
Ignition Source
CourtesyProf. Chuck Sheppard,Univ. of Tulsa
42
A CONFINED SPACE EXPLOSION
43
EXTENT OF EXPLOSION
11 PEOPLE KILLED130 TON CAR OF VINYL
CHLORIDE TIPPED OVERGUARDHOUSE DESTROYED
BRICKS FOUND 400 FEET AWAY
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
45
46
FIRE PROTECTION SYSTEMS
SPRINKLER SYSTEMSFIRE WATER PUMPS
FIRE RATED WALLS AND BARRIERS
47
BROKEN SPRINKLER MAIN
REMAINS OF POLYMERIZATION BUILDING
48
49
PROPERTY DAMAGE SUMMARY
POLYSTYRENE BUILDING DESTROYED
BUILDINGS 1,4,5,8,&12 SUFFERED FIRE AND WATER
DAMAGEPUMP HOUSE DESTROYEDSEVERAL AUTOMOBILES
DAMAGED
50
INVESTIGATIONSEARCH 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
TESTIMONY
STYRENE VAPOR INSIDE PS BUILDING
WHY?FAILED SIGHT GLASS ABOVE
RUPTURE DISK
52
POSSIBLE IGNITION SOURCE
ARCING MOTOR?HOT SURFACES?
ELECTROSTATIC DISCHARGE?
53
WHY DID THE REACTION RUN AWAY?
WRONG CAM ON THE RECORDER?
ORTHE PENS STUCK?
54
LESSONS LEARNED
MAINTAIN CRITICAL PROCESS EQUIPMENTINSTALL AUDIBLE ALARMSCENTRALIZE CONTROL OF BATCH OPERATIONSELIMINATE SIGHT GLASS VIEWPORTS FROM RELIEF LINESHAVE SEMI-AUTOMATED DISCHARGE SYSTEMS (REMOTE DUMP VALVE)
55
BROADER LESSONS LEARNED
USE DOW FIRE AND EXPLOSION INDEX FOR SPACING OF PROCESS EQUIPMENT STORAGE TANKS, AND TANK CARKEEP UPDATED DISASTER CONTROL PLANS
56
OTHER LESSONS LEARNED
REDUNDANT PROCESS CONTROL EQUIPMENT
LOCATION OF EMERGENCY POWER AND FIRE PROTECTION
FAIL SAFE VALVES ON STORAGE TANKS
57
ACKNOWLEDGEMENT
DR. WALT HOWARDLASALLE FIRE DEPARTMENT
MR. ROBERT GUERARDMR. JOHN PAUL LACOURSIERE
SACHE COMMITTEE