Document mmZkpZYbkQZ2Vd7xdwbboD60Z
ENGINEERING DEPARTMENT OLEFINS DIVISION
UNION CARBIDE CORPORATION SOUTH CHARLESTON, WEST VIRGINIA
TRANSMITTAL MEMORANDUM
June 30, 1966
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received
JUL 1 1966 R. N Wh eler
Mr. J. W. Ackenhusen
Mr. C- P. Bennett Mr. F. D. Dexter (k)
Mr. A. P. Dunlap Mr. M- B. Elsenhour Mr. J. F. ffrAmann Mr. J. H. Field Mr. D. W. Finn Mr. P. F. Fisher Mr. C. E. Fry Mr. N. A. Glmber Mr. Lee E. Hall Mr. R. j. Hanna Mr. J. R; Hazle Mr. H. V. Hooper Mr. 0. A. Holt Mr. H. J. Karavan
Mr. R. P. Little Mr. J. M. McKee Mr. D. E. Richardson Mr. J. A. Riddle Mr. H. H. Savage Mr. M. S. Sutherland Mr. R. J. Taylor "^Mr. R. N. Wheeler Mr. E> F. Williamson
Mr. M. Johnson Mr. W. S. Lanier Mr* C E> McConnell, Mr. S. P. Smith Mr. R. V. Wallin
FROM:
V. R. Manning
SUBJECT: Polyvinyl Chloride Industry Safety Meeting
Herewith la your copy of the subject memorandum, dated June 30, 1966, prepared by Mr. Marlon Johnson and Mr. W. S. Lanier. The memorandum pertains to an Industry-wide meeting sponsored by the Ffaudler Company to
discuss general aspects of safety In polyvinyl chloride plants. Comments or questions concerning this report should be directed to the authors.
WRM:rc Attachment
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POLYVINYL CHLORIDE INDUSTRY SAFETY MEETING
Sponsored By The Pfaudler Company Rochester, New York
Date: April 26 and 27, 1966 Reported By: W. S. Lanier
M. Johnson
SUMMARY
As a sequel to the meeting of polyvinyl chloride producers following the Thompson explosion, a second meeting of these producers was called and hosted hy the Pfaudler Company* All hut three of the domestic PVC producers were represented; some had several representatives.
The formal meetings consisted mainly of lectures on the design of Pfaudler equipment; only two speakers discussed safety primarily (a copy of the formal program is appended). The PVC manufacturers exchanged experiences related to safety at the dinner tables and an Informal session of the group*
Several recommendations on layout, equipment, and operating personnel protection were endorsed hy the producers as safety improvements. A list of these recommendations Is appended.
Fatalities have occurred at three producers' facilities in the past year. Tennaco (Cary) and Borden have each found a man on top of their blending tanks, apparently asphyxiated hy fumes. UCC lost three people due to the fire and explosion which occurred when the lower manhole on a reacting autoclave was erroneously opened. Several other incidents have occurred which, although fatalities or major fires did not result, are considered serious: several detonations have occurred in tanks or compressors which handle vinyl chloride monomer and operate under vacuum conditions at some time in the cycle.
Mr. Bill Doyle of Factory Insurance Association presented a compari son of FVC plants which were built before the Thompson explosion and those built after the explosion. The increased concern with safety was obvious, but several of the more expensive recommendations of the Insurance companies have not been adopted across the board. The "new" plants tend to either eliminate sight glasses or provide the safer, more expensive models. They also provide larger relief capacities on the polymerizers (autoclaves) and higher ventilation rates in the control rooms. Monomer recovery areas have
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been located some distance from the reaction areas in the "new" plants. Deluge water spray systems, rather than closed-head sprinkler systems, and concrete autoclave structures, rather than steel-only structures, although recommended by the insurance companies, were installed in only about half of the "new" plants.
A list of recommendations by Pfaudler on the normal handling and operation of glass-lined autoclaves is attached.
DISCUSSION
Safety Recommendations (From the Meetings) The following list of items was generally agreed upon by the FVC
producers as design and operation concepts which would improve the operaring safety of PVC manufacturing facilities:
1. Use Nash compressors in monomer recovery area. These compressors use liquid in the casing to seal between the Impeller and the caBing. The liquid has a cooling effect on the compressed gas and also will tend to saturate the gas which minimizes the static electricity hazard.
2. Locate monomer recovery area some distance from the reaction (polymerization) area. The reaction area is considered the most hazardous, and removing the potential fire-feeding monomer from the adjacent area is desirable.
3* Design control room ventilation system for 15 turn-overs per hour and take suction in a monomer-free area. This should prevent build-up of sufficient monomer vapors in the control room to exceed the lower explosion limit.
h. Use deluge-type fire protection systems rather than closed-head sprinklers. The deluge systems have extremely high water flow rates which means more cooling.
5* Use Pressure Products sight glasses if sight glasses cannot be eliminated. The Pressure Product device seals the two tempered glasses around the O.D., thereby putting the glass in compression rather than using gaskets to seal the glass on the upper and lower flat surfaces which puts the upper glass in tension. The compressive strength of glass is several times its tensile strength.
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6. Provide short-stop tombs. These bombs contain a reaction inhibitor which, if drained into an autoclave, will stop the reaction.
7* Provide multiple safety devices to protect personnel inside autoclaves. When inside autoclave, the man should wear wrist straps, rather than ankle straps (ropes not connected). A boat trailer winch with which one man could lift an injured worker out of the autoclave is provided by one producer. Also, some means, either an outside observer or an alarm which must be signaled every few minutes, should be employed to spot an injured worker quickly.
Informal Discussion of Incidents by PVC Producers
Mr. Jim Hahn, the plant manager of Tenneco's Burlington, New Jersey plant, called the meeting. The following Incidents were related:
1. (Tenneco) detonations in "stripper" (blow-down tank) when dry air (-4o"P dew pt.) was used to pressure the slurry to "screener" (skin-trap). Now use nitrogen. Other manufacturers use plant air (0#F dew pt.); none have had similar problems. The strippers are pulled down to below 20" hg. vac. The autoclaves are also evacuated.
2. (Tenneco) detonations in discharge of both stages of reciprocating compressors in monomer recovery service. Other manufacturers have also had detonations. It was postulated that air slugs are pulled into the vacuum systems and, when compressed, explode. The possibility that vinyl peroxides are the culprits was also suggested.
Note: Several manufacturers are now using the liquid-sealed Nash centrifugal compressors to minimize danger due to vacuum operation; none of them has had any detonations.
3* Protection of laborer cleaning reactor internally. One manu facturer has outside man check visually every ten minutes or so (no buddy system)
Goodrich has portable alarm which inside man must pull every three to five minutes to prevent sounding. If line kept taut more than 30 seconds by tying it to agitator, etc., the alarm goes off. The alarm costs approxi mately $500.
Several manufacturers use wrist straps on inside man (ropes not con nected); one has portable winch so that only one man outside autoclave can extract inside man.
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(UCC) - Opening of lover shell manhope In live reactor incident was related by Hal Savage.
5. Dump line breakage - Several manufacturers have lost monomer charges through slurry dump lines which broke. Some had used Victaullic joints to make cleaning easy, but most have now gone to welded lines.
6. Fatalities by asphyxiation - Tenneco and Borden have had recent fatalities by suffocation in slurry blending tanks. In each case, the man was apparently looking into top openings of tanks, fainted and was later found draped over edge of tank, head one to two feet below top of tank.
7. Phenol hazards were stressed by several men present. Phenol is used as a polymerization inhibitor (see Item 6 under Safety Recommendations).
8. High pressure water cleaning of autoclaves is being used successfully by U. S. Rubber. Under evaluation by Pantasote.
"Safety in PVC Plants" (After-dinner speech by Mr* Bill Doyle, Factory Insurance Association)
Mr. Doyle's talk centered around a comparison of the PVC plants which were built before the Thompson explosion and those built after the explosion, both groups being insured by members of his association. The plants were mainly located in the northern half of the U. S. There are ten "old" (before Thompson explosion) plants and six "new" plants. Data were not available for all comparison items from all the plants.
Sight Glasses
Factory Insurance Association recommends only the Pressure Products sight glasses.
Old Plants (10)
New Plants (6)
7 - ordinary type 2 - Pressure Products type 1 - no sight glasses
3 - Pressure Products type 3 - no sight glasses
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Pressure Relief Devices
Factory Insurance Association has developed curves for run-away reactions by relating rate of heat release (low, medium, high, very high) versus safety valve size recommended. liability ruling by the courts prevent their publishing the curves, but the safety valve sizes for the new plantB are indicative:
Old Plants (10)
S. V. inlet Size, in.
3" V 4" + 8" Rupture Disc 6"
vessel Sizes, gal
1600, 2200, 1100, 2000, 3000 3750
2250, 3750 2250, 3700
New Plants (6) - 3 of new plants' safety valves were sized off curves developed by Factory Insurance Association.
3" 2000, 2200
Indicated relief capacity for 3750-gallon autoclave is 3" safety valve plus 3" rupture disc from curves.
Monomer Recovery Area Location
Factory Insurance Association recommends that the monomer recovery area be detached from the reaction area, and monomer storage in accordance with the code for IPG storage, - 400 ft. separation for 500-M gal, 100 ft. for 30-M gal, with the use of dikes, and spray systems.
Old Plants - monomer recovery area and reaction area combined. New planta - monomer recovery area detached from reaction area.
Ventilation of enclosed reaction buildings
Old Plants
New Plants
8 - for comfort only 2 - 2 to 15 turnovers per hour
6 - have at least 14 turnovers per hour
Fire protection - Factory Insurance Association recommends deluge systems.
Old Plants
New plants
7 - closed-head sprinklers 2 - deluge 1 - closed-head sprinklers +
deluge
2 - closed-head sprinklers 4 - deluge
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Several plants have vapor detectors which can speed up ventilation systems and/or actuate sprinkling system.
Autoclave Supports - Factory Mutual recommends concrete supports. Old Plants and New Plants - half of "both types are steel, the other half are concrete.
Short Stop (Reaction inhibitors) Mr. Doyle asked if they were used. -- A few companies use them.
StyTene bombs on portable carriers with high pressure nitrogen to blow the styrene into the autoclaves are used by one company. Other companies use styrene or phenol on occasion.
Catalyst Storage No problems likely if stored in accordance with duFont literature.
Handling and Operation of Glass-Lined Autoclaves Pfaudler recommends the following: 1. Autoclave Installation - use ball bars and *11 hoist loops
provided when lifting vessels. Do not lift a vessel by one lifting loop. 2. Operating Pressure - do not exceed design pressure for fear of
spalling glass at high stress points. The pressures which the steel vessels could withstand before the stress limits are exceeded are many times the pressure at which spalling of the glass will occur.
3- Flange protective rings - use stainless steel spool pieces to prevent loss of glass on those flanges which must be broken frequently.
4. Use Torque wrenches to tighten flange nuts to prevent glass breakage due to overtightening of nuts. Torque wrenches will give leak tight seal with minimum bolt tension.
5- Regular cleaning of Jacket (O.D. of autoclave which is covered by the Jacket) Is considered essential if heat transfer capacity Is to be maintained.
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-76. Relief valve settings should be 90 percent of design pressure; normal operating pressures should not exceed 80 percent of design pressure. (Note - since UCC autoclaves are designed for a test pressure of 1J0 percent of MA.WP before glassing, the second 10 percent below design pressure could probably be eliminated but Pfaudler will not guarantee integrity of the glass if pressure exceeds design.)
W. S. Lanier H. Johnson June 3, 1966
UCC
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DESIGN FOR SAFETY IN
POLYMERIZATION
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PROGRAM
TUESDAY, APRIL 26
Morning Session
Moot ot tho Towno Imr -- Town# Mouse
Chairman ot Session --" ft. H. Storrett -- Vico President, CnginoofinQ
$i45 Introductory Remarks
I. T. Cork# -- Vko President, MarkoHng
tatic Vessel Dotign Considerations D. E. Kropp -- Manager, Product Engineering
Hoot lithcfigc Considerations J. M. Procepio -- faction Manager, Product
EnginooHng
Material* tor Gaskets I. G. Staple* -- Tocknicol Enpinooring Specialist
Nozsloi and Split Flange* ft, E. Knebteck Section Manager, Product
Engineering
Manholes, Protection ftingi. Gaskets end Camps H. G. Melino -- Manager, Engineering Standard*
Lunch -- 12 tSO. University kit Room -- Towno House
Afternoon Session
1.30 Agitator* and Sealing Devices E. S. Harrison -- Manager, Mixer Engineering
Seal lubricating Systems C. J. Nunliit -- Manager, Product Developaent
Sight and Ugbt Glasses D. E. Kropp -- Manager, Product Engineering
4i00 Moot ot Pfaudlor Factory (a chartered bus will loauo the Towno Hoese ot S*4J til.)
Choiraan of fasilon - E. J. Wight -- Manager, Cottaaer Service
5t30 Chortorod bus loaves fro Podory for Town# House
Dinner Meeting
6s!5 Cocktails -- Heritage Room -- Towno House
700 Dinner Town# Room Towno House Chairman of Session -- ft, S. Payne -- Manager, Vassal Solas Dept.
Speaker -- Mr. W. H. Doyle Chief Cheaical Engineer Factory Insurance Association
Topic -- "Evolution of Protective Practices in Polyvinyl Chloride Plants"
WEDNESDAY, APRIL 27
Morning Session
Meat ot the Towne Room -- Towne Hows#
Chairman of Session -- ft. H. Stonretf -- Vice President, Engineering
1*45 Pressure Sensing Devices E. J. Nunlist -- Manager, Product Development
Softies and Softie Holders J. S. Eyster -- Engineering Specialist
Safety Relief Devices D. I. Diehl Manager, Test Center
Explosion Protective Systems ft, C. Clyde -- Project Engineer
Summery J. M. Culotto -- Chief Project Engineer
Lunch -- 12i30. Celeste Room -- Towne House
Afternoon
No formal session. Individual conferences with Pfoudler
personnel moy be arranged.
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