Document RjpDd5Ea2Y72qXN4K5qpEanzE

A brief remind rto busin ssmen who in 1962 thought the Polaroidcamera was just an expensive toy. Th larg reactor is one answ r "Large reactor technology" may prove the most feasible way out of the vinyl chloride emission morass. One large re actor for polymerizing vc resin into PVC requires hundreds fewer flanges and valves than do a dozen small ones. This drastically slashes the number of potential vc leak points. The concept is already working for Japan's Shinetsu Chemical Industry Co., which built Japan's only 35,000-gal. PVC reactor in 1970. And it is now working for Shintech, Inc., a joint ven ture of Shinetsu and Robintech, Inc., of Fort Worth, Tex. Shintech's Freeport (Tex.) Pvc plant is using four 35,000gal. reactors to produce the same amount of pvc that would be made in some 30 smaller reactors in traditional plants. The giant reactors require man ual cleaning no more than once a year. Shintech's experiences since the plant came on stream in October have been more than encouraging. "All our tests indicate we're well below the 1-ppm level without the use of respirators," claims James M. Danial, Shintech vicepresident. Treatment. The key to Shinteeh's sharply reduced cleaning schedule is a proprietary treatment applied to reac tor walls after each batfh nf pvr ;a made. The coating is sprayed on under high pressure after the reactor .is purged with a hydraulic spray and a vacuum. "The whole plant is tighter than older pvc plants," claims Joseph L. Brawner, Shintech's plant manager. "We've used welded construction on lines Bolding vinyl chloride wherever we could, eliminating flanges." ~frhe plant is entirely computer-controlled and operates with only 25% of the 163man work force required at Robintech's older Painesville (Ohio) plant, which has about the same capacity. Tenneco Chemicals, Inc., has licensed the technology for its new PVC plant in Pasadena, Tex. The plant has five 35,000-gal. reactors and a capacity of 250-million lb. According to Joseph P. Fath, a Tenneco Chemicals vice-presi dent, the plant incorporates some reac tor cleaning technology that Tenneco developed on its own which will "ob viate reactor opening and entry in the long run." But. Fath admits, there mar Still be maintenance situations where respirators are needed? Its not always wise to be negative. New developments have a way of changing old preconceptions. Take Mississippi for example. Nothing but 'gators and mint juleps, right? You really should get the facts. In our book we tell you about our available labor and raw materials and abundant transportation and favorable tax laws. Of course, you already know about our great climate. You see it on all those New Year's football games. If you're smart, you'll write for the book. If you're even smarter; you'll move your plant here. And if you're a genius, you'll fly down tomorrow and make some Polaroid shots of the place. Along with my Re-Think Mississippi button please send me infonnation on: Industrial opportunities in Mississippi. (Attach coupon to your business letterhead.) Travel information (our new travel guide). See Mississippi while looidng tor a new plant site. Name___________ Tula RitQnere ' Address___________ i CityState. Zip Mleeleelppi A & I Boerd/P O. Box 849 Jackson, Mississippi 119205 i I ! I j i I 1 batch of pvc is made, the tanks are hosed down to flush out unreacted vinyl cloride monomers and accumulated PVC resin. "We are down to manual clean ing after only 2% of batches," says Goodrich's Harrington. "With hydrau lic spraying, we are at 5 ppm for only five minutes instead of 30 minutes when we clean a reactor," adds Eli Zinn, plant manager at Diamond Shamrock Chemical Corp.'s Deer Park (Tex.) plant. Both Goodrich and Diamond Sham rock use water hydraulic sprays. Other PVC manufacturers, such as Union Car bide Corp. and Monsanto Co., are try ing closed-reactor solvent cleaning sys tems, and Carbide officials claim that reactors at their Texas City plant now need manual cleaning only once every two months. Another problem. Even with perfected cleaning methods, however, the vinyl plastics industry will still have another hurdle to overcome: recovering un reacted VC monomer that may be trapped in finished pvc resin. If the monomer is not removed before ship ping, it can escape when the resin is heated for fabrication. This then threatens fabrication workers with ex posure to unacceptable vc levels. Recovered vc can be recycled back into the PVC process, so Pvc manufac turers are especially interested in de veloping technology for stripping un reacted monomers from the resins. But so far, they are facing a Catch-22 type of problem. While the goal is to let fab ricators heat the resin without releas ing vestiges of VC, current stripping , methods also require heating. The re- ' suit can be overheating, which causes hydrochloric acid ^molecules to break away from the resin. The resin then turns brown and weakens. "Once this degrading starts at the pvc manufac-, turing level, it continues throughout: fabrication, so the goal is to get the vi nyl monomer out faster without excess heat," explains Goodrich's Harrington. One new process that looks promising involves use of a vacuum in the reactor to strip much of the unreacted mono- j mer before the resin is dried. A number of pvc manufacturers have programs , under way to develop recovery meth ods. Goodrich, for one, hopes to market a system by yearend. But osha is leaving nothing to chance so far as claims for any system go. Its vinyl industry standard not only specifies exposure limits but mandates j that all vinyl producers keep records of worker exposure and monitor vinyl chloride levels wherever they are ex pected to exceed 0.5 ppm. The fabrication plants may escape the monitoring problems, because most can establish that they have exposure I levels below 0.5 ppm. "In most fabrica-1 ting plants, there are already ducts and | vents above the blenders to meet ear-1 lier dust and fume regulations," notes J 34 H BUSINESS WEEK. April 14. 1975 JINDUSTRIAL PRODUCTION 1 MMmwmp UCC 093818 4