Document DNRzyKoL83Oq4XgVNDpEwO0a

POLYVINYL CHLORIDE INDUSTRY SAFETY MEETING Sponsored By The Pfaudler Company Rochester, New York Date: April 26 and 27, 1966 Reported By: V- S- Lanier M. Johnson SUMMARY As a sequel to the meeting of polyvinyl chloride producers following the Thompson explosion, a Becond 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 autoc--l-a--ve was erroneousv ly-*or --p-e--n--e--d-. -S-ev--eral o- th---e--r--'--in- --cide"nts ha--ve- -oc-c--u---r-r-e---d- , - W* which, although fatalities or major fires did not result, are considered | serious: several detonations have occurred in tanks or compressors which\1 ^h v* t*" u handle vinyl chloride monomer and operate under vacuum conditions at some time in the cycle. -- //_a iIftPeK VC& Vl-tst Tt "c ''Pf //r - 7L C ~ A/#7 7Z-jr fin- pvnts tecttW dr r*f. CTZ-ftf* Mr. Bill Doyle of Factory Insurance Association presented a compari- son of PVC plants which were built before the Thompson explosion and those built after the explosion. The Increased concern with safety was obvious. u > but several of the more expensive recommendations of the insurance -companies have not been adopted across the board. The "new" plantB tend to either eliminate sight glasses or provide the safer, more expensive models. They fS also provide larger relief capacities on the polymerizers (autoclaves) higher ventilation rates in the control rooms. Monomer recovery areas have UCC 093002 2- - 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. e S'v-' , ym A list of recommendations by Pfaudler on the normal handling and yt 'y operation of glass-lined autoclaves is attached. DISCUSSION Safety Recommendations (From the Meetings) tf *' 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 FVC manufacturing facilities: *'C 11 -fit* rU^- p, 1. Use Nash compressors in monomer recovery area. These compressors use liquid in the casing to seal between the impeller and the casing. 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 W (polymerization) area. The reaction area is considered the most hazardous. fa *** and removing the potential fire-feeding monomer from the adjacent area is *^*'**"j desirable. ^d***^, fL Vf>, vdH:V esign control room ventllati system forfll n-overs per suction in a monomer-free areeaaD.) This should prevent build-up of sufficient monomer vapors in the control room to exceed the lower explosion limit. (UA* Tf k. Use/deluge-type fire protection systems rather than clOBed-head iprinklers. The deluge systems have extremely high water flow rates which means more cooling. ,i ^ * ** ` 5* Use Pressure Product^ sight glasses if sight glasses cannot be eliminated- The Pressure Product device seals the two tempered glasses around^ the O.D. j/'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 The compressive strength of glass 1b several times Its tensile strength. e UCC 093003 fill jL p ^ --- ninr- -3- 6. Provide short-stop 'bombs. These bombs contain a reaction IaJj. drd 4' ,c - [.Mif inhibitor which, if drained into an autoclave, will stop the reaction. ^e"> e*) 7. Provide multiple safety devices to protect personnel inside ect 0 autoclaves. When Inside autoclave, the man should wear wrist straps, rather /r s&rvf than ankle straps (ropes not connected). A boat trailer winch with which ^ 'r one man could lift an injured worker out of the autoclave Is provided hy one /-y tvf producer.^Sso. some means, either an outside observed) an alarm which mug}) he signaled every few/minutes, should he employed to spot an lnji^ed worker quickly. ;^a:m / Informal Discussion of Incidents hy FVC Producers Mr. Jim Hahn, the plant manager of Tenneco1s Burlington, New Jersey plant, called the meeting. The following incidents were related: 1. (Tenneco) detonations in "stripper" ("blow-down tank) when dry air (-40F dew pt.) was used to pressure the slurry to "screener" (skin-trap). Now use nitrogen. Other manufacturers use plant air (0F dew pt.); none have had similar problems. The strippers are pulled down to below 20" hg. vac. The autoclaves are also evacuated. r 2. (Tenneco) detonations in discharge of both stages of reciprocating ressors 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. ^-JJote: Several manufacturers are now using the liquid-sealed Nash centrifugal compressors to minimise 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), 1 ! , U' t' -Vp1/L , I1 p Goodrich has portable alarm which inside man must pull every three to five minutes to prevent sounding. If line kept taut more than 3 seconds hy 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 ft I.V extract inside man. UCC 093004 (UCC) - Opening of lover shell manhope in live reactor incident was related by Hal Savage. 5- Dump line breakage - Several manufacturers have li charges through slurry dump lines which broke. Some had us^d Victaullic JointB to make cleaning easy, but most have now gone to weldei 6. Fatalities by asphyxiation - Tenneco and. Borden have had recent/ fatalities by suffocation in slurry blending tanks. In each case, the man / frt / (rfK (s-:t was apparently looking into top openings of tanks, fainted and was later C ^ found draped over edge of tank, head one to two feet below top of tank. `v ` J/SY-- I 7* Phenol hazards were stressed by several men present. Phenol is f ^ used as a polymerization Inhibitor (see Item 6 under Safety Recommendations). 8. High pressure water cleaning of autoclaves is being used rsuccessfully by U. S. Rubber. Under evaluation by Pantasote. brU. <+U- "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 pi ants 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) ~ 7 - ordinary type 2 - Pressure Products type 1 - no sight glasses J New Plants (.6..) "Uf l?/ D0.'1 y 3 - Pressure PProducts type - / 3 - no sight glasses a.*..' r. a fLA. J UCC 093005 -5- 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 plants are indicative: Old Plants (10) S. V. inlet Size, in. 3" k" 4" + 8" Rupture Disc 6" yj * Vessel Sizes,. gal WT.i L-J^: jvr*. 1600, 2200, 2250 , 3750 I J *(. ^ 1100, 2TM000, 2TM250, 3TM700 A/ U*f JJ] 3000 3750 M iT + <i>s New Plants (6) - 3 of new plants' safety valves vere sized off U 1'^ curves developed by Factory Insurance Associationi. 1 y 3" 2000, 2200 Indicated relief capacity for 3750-gallon autoclave is 3" safety / JHi r ,3'- 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 LPG storage, - UOO 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. Mew Plants - monomer recovery area detached from reaction area. Ventilation of enclosed reaction buildings - fy-s /j Old Plants Mew Plants a*,- opPr 1 U'j AMi/fi-tc yv j,y/u' AS OSp, i ** 1s d**it*u* ' 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 k - deluge , jj J1 ** **r( Ucc 093006 6- - Several plants have vapor detectors which can Bpeed 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) / r-L Mr. Doyle asked if they were used. -- A few ccmpanies uBe them. \ yy Styrene bombs on portable carriers with high pressure nitrogen to blow the/ styrene into the autoclaves are uBed by one company. Other companies use \ /* ,7r/_ Btyrene or phenol on occasion. /y y CatalyBt Storage _-- ------------ -- No problems likely if stored in accordance withSduPont literature. Handling and Operation of Glass-Lined Autoclaves Pfaudler recommends the following: ^ ft# J t, ^// 1. Autoclave Installation - use bail bars and all hoist loops provided -when lifting vessels. Do not lift a vessel by one lifting loop. -- 20/ tr 2. Operating Pressure - do not exceed design pressure for fear of 'spalling glass at high stress points. The pressures which the steel vessels^ 41' could withstand before the stress limits are exceeded are many times the j pressure at which spalling of the glass will occur. /jC44. . W 3* Flange protective rings - use stainless steel spool pieces to 6': prevent loss of glass on those flanges which must be broken frequently. 4. Use Torque wrenches to tighten flange nuts to prevent glass lbreakage due to overtightening of nuts. Torque wrenches will give leak J-C/',-d.''.4'.'T'%'iU~ ^/4/ r tight seal with minimum bolt tension. /t 5* Regular cleaning of Jacket (O.D. of autoclave which is covered y ' by the jacket) is considered essential if heat transfer capacity is to be ( maintained. J> UCC 093007 -7- 6. Relief valve settings should he 90 percent of design pressure; / normal operating pressures should not exceed 80 percent of design pressure. (Note - since UCC autoclaves are designed for a teat pressure of 150 percent of MftWP 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 M. Johnson June 30> 1966 >A > ' V/- .^.V: ' - UCC 093008 i s