Document DdYMQoQdBjKpVpJGyYMr9nr7N

*o CO PgUU--Jhs* oo t-' zi t 3 CO " rti PQ , High mpsrature '-reep and. Rupture - Makers of gaskets, packing, try asbestos replacements U.S. and foreign manufacturers are using such materials as flexible graphite for packing; chiorite/graphite sheet for spiral-wound gaskets; and mica, glass fibers and others. ffective Jan. L 1987. asbestos will application for sealing material in Ebe banned from gaskets anc pack chemical process plants, the others be ing in Sweden. And Norway. Den ing valves, pumps, compressors and mark and Finland are expected to foprlessure vessels). Users are reluctant low suit. The switch to more-expensive to change to cosliier materials they substitutes will cost the petrochemical don't have experience with, say industry alone up to S2 million, accord manufacturers. ing to the Swedish Assn, of Chemical "Many vaive manufacturers Industries. throughout the worid still use asbestos U.S. industry faces no such immedi as tne standard material- for gaskets ate threat, but gasket anc packing and packing.'- observes Donald Glover, manufacturers are bury touting a va head of the piping and technical section riety or" asbestos substitutes, proudeo with Santa Ft Eraur, Inc. (Alnambra. i by increasingly strict regulations, 'legal Caiif.i. Industrv spokesmen report that actions, at. inability u- get liability in surance. ana the U.S. Environmental Protectioii Agency's proposed total bar, vaivemaxer; stocxec up or. asoestos i braided packinc before Crane and oth- I er companies stopped making it. but ! on asbestos tsee story on p. IS). those supplies are starting to run iow. ! The smorgasbord of replacements in one contender -- At the Houston semi- i cludes flexible graphite, carbor. and nar. the virtues of one particular mate I graphite yarn, glass fibers, aramic. po riaTk- flexible or expanded graphite -- lyhenzimidasoie (PBIi. poiytetrafiuor- 1 were extolied by several speakers. oethylene (PTFEi. ceramics, mica and Flexible graphite cap withstand terr.- various metals. j peratures of more than 5.000T (com- No single materia) matches asbestos' : pared with about 1.200T for asbestos), strength, chemical resistance and flexi i say suppliers, while cautioning that it is bility over a wide temperature range, limited to about 750-850'F in the pres says Richard White, director of re ence of oxygen, and to around 1.20GT search and development with Gariock in steam. Inc. (Palmyra. N'.Y.i. Bui equal or supe "Graphite packing is proving to meet rior properties are obtainable by com or surpass all the positive characteris bining two or tnree materials, he toic a tics of asbestos." the Houston meeting seminar on asbestos-substitute gasket ; was toid by Rudy MacDonald, a piping ; anc packing materials, held in Houston : component specialist with Exxon Co. in eariy August. (The meeting featured i UFJL (Baton Rouge. La.k To date, it is speakers representing producers and the only non-asbestos material that Ex- users of gaskets and packing. I j xon has found to be fire-safe, he says, still the choice -- In the push to en "and a refinery cannot have leaking courage substitutes. John Crane Hou- i flanges in a fire." Most data on asbes- daille Inc. (Morton Grove. 111.) last year , tos suostitutes focus on process com- stopped making its 187-1 braided asbes j patibility. he adds, and fire-resistant tos packing, long considered an indus , data are virtually nonexistent. try standard. And several other manu Flexible graphite, developed by facturers have ceased production of Union Carbide Corp. about 2u years simiiar products. ago. was lime usee until recently be- i Despite this. U.S. industn spokes ! cause it costs toe much. Now it has men calculate tr.at asoestos still has around of tne packing market, up I well over 507- of the packing and gas from ]-2r) a year or two ago. says Peter ket market, compared to the traditional , Petrunieh. manager of customer tech 8(*-9(T' (pipe flanges are the biggest nical sendee with Union Carbide Elec- cat out ofthe bag.! Millions of children miehr ne\er nave me: Dr. Seuss and"his famous Cat had it nor been for The New York Public Library. That's because our renowned children's librarian. Anne Carrolj Moore, save his first book an outstanding review. He became famous ovemisht. and Dr. Seuss himself credits her with his success. Others too. credit our librarians. "The people who w'ork here." sal's author David McCullough, "provide a sendee to the whole of society that's never sung enough." Indeed, tne librarians are the very heart of the Library. They are the ten librarians who answer five million relephone inquiries a vear. They are the librarians who introduce children to the magic of liter ature and help adulrs find employment through our ]ob Information Center. They are also the librarians who select and preserve books for users of tomorrow. The Library can help just about anyone with anything. Even a Doctor with his Cat. J j j i nrK^:TOfi The New York Public Library WHERE THE FUTURE IS AN OPEN BOOK jwja-ujp1 i CHEMICAL ENGINEERING OCTOEEl: X !-* jhaW coSiiii3'" ' ironies Div.'s Specialty Products Group graphite the standard packing for (Cleveland). small, forged steel valves (up to 4 in. j. Petrunich explains that the material i The company plans to use the material is made from natural flake graphite, | in all valves. rather than from textile threads. The Rockwell has partially offset the graphite is expanded several hundred higher cost by redesigning its valves to times into a light, fluffy material by j use fewer and smaller packing rings mixing it with sulfuric or nitric acid, j than with asbestos. Braided carbon then calendered into a sheet (without . rings are placed on either enc of the [rsx(^: it r~ ; How asoesios Daewoo car. oe reo.aceo Dv cine1 maienais Crcie 20 on Reaoer Service Card 24 CHEMICAL EXGIXEERING'OCTOBE): T. IHSf, binders or additives). Although price i ring assembly to prevent extrusion of has been dropping, the product still i the flexible-graphite sealing rings. costs 30-50f:r more than asbestos pack While the material attracted much ing. says Petrunich. But he ciaims that : attention at the Houston meeting, sev- it seaie better and lasts 5-10 times long i era) others are also favored by packing er than asbestos. and gasket makers. One drawback is that graphite, an ! "Only the top of the line is made fruit. electrical conductor, can enhance gal | flexible graphite." says Garlock's vanic corrosion in stainless steel. Zinc, a i Wniie. adding that his firm hasn't made common sacrificial inhibitor, has the I asbestos packing for five years. A typi- limitation of melting at 787eF. So. Car cal Gariock design is to put giass fibers bide now ofiers a phosphorus-based in ; in the core for strength, carbon around hibitor that Petrunich says is more ef ; that (for heat transfer and thermal sta- fective. He also points out that i bility). and PBI on the outside. Tne impurities in asbestos can cause corro ! latter material, though it costs 40 times sion problems. . as much as asbestos, he notes, can One vaive manufacturer that has . stand more than 1.200T without burn- done extensive testing of flexible [ ing or melting, and resists most cbemi- graphite is Rockwell International s ; cal products. Measurement k Flow Control Div. "We use glass a lot." says Geurge (Pittsburgh. Pa.). Rockwell reports bet McKiliop. product manager for John ter performance than asbestos in seals Crane Houdaille's Packing Div. "Tne at higher temperatures, and has made cost is slightly higher than asbestos. pack inf rnr (up to ). the material offset the its valves to icking rings ideo' carbon end of the CeCt.ing aesiar .idtr. = 1C li 1I -me t 5 ;ior- ? xtrusion of : rings. ictec much eetmg. sevb\ packing : j t made from Garlock's -,asr,'t made ars. A typig;as? fibers doi. around berma; sta- ztsiae, The ?ts 40 times notes, can .bout burnoust cbemi- ; ; [ i [ { , j ; v<- ue zor o..... Div. "The . asnestos. but it ha? good strength and chemical resistance. We recommend it up to 1.200`F. for gaskets -- In the gasket area, chlorite/graphite sheet, on the market ! since 19S3, is the most popular non- j asbestos filler for spiral-wound gas- j kets, according to Samuel Thomas, vice-presideni of Flexiiallic Gasket Co., (Eellmawr. KJ.i. This mixture matches j asbestos' performance at a comparable j cost, he says. Spiral-wound gaskets i that have a flexible-graphite filler offer j superior sealing and cyclic thermal- or j pressure-loading properties, he adds, j hut cost SMOOT more. Flexiiallic Ltd CKeckmondwike. En- ! gland- markets a company-developed . mica cY>oritt-ba~ec spiral-wound gas- 1 ket that it claim? matches asbestos products for a similar price. (This com- 1 party and Ftexltailic Inc. ame owned by : Turner anc NV-vah PLC. Manchester. : England.! Cokr, Gee. general manager of the firm's Fiexicarb Div.. estimates that asbestos still nas more than 50" of the Eritisr gasket market, but feel? that a new asbestor-labeiing regulation will accelerate substitution. Ir. compressed gaskets -- conven- ; tional asbestos encapsulated in a ruiber lender -- a ramie, glass fibers anc ' mica are being used as reinforcement, while suer, materials as talc, barium sulfate, clay and mica are fillers. Jack Harris, vice-president of Durable Manufacturing Co. (Lionvilie. Pa.), says the > performance of non-asbestos materials j equals asbestos for moderate condi- j tions. but the gaskets cost 50-100" j more and cannot handle temperatures ai'iivr m? or certain chemica' envl- ' ronrnent.- For tni? application, flexible - graphite is several times more costiy I tnar. asbestos, he says, partly because j the gaskets are cut from sheets and | much material is wasted. ! "In sheei material for gaskets, we ! are basing a difficult time finding a ! substitute that has anywhere near the : temperature qualities of asbestos,'" j adds a spokesman for another leading i gasket maker. `*We would like an SOOT j material and we are looking at a couple ; of fibers nov. he says, "hut most high- : temperature fibers are inorganic and don't have crush resistance." i Tne Swedish forest-industry stan- > dardiaation group is recommending I that aramid-reinforced mineral gaskets . SMJim API PUMP FROM K0NTRO. NOBODY ELSE. The only leak-proof centrifugal pumps that meet API 610 6th Edition specs. Kontrc SEAL'LESS Dumps offer imDortant advantages over al> otner AP. pumps. No seals to leak, be cooled or to be maintained. Eliminates nazerds of fire, toxicity and environmen tal contamination Capacities tc 5000 GPM Temperatures to 7S0F without cooling. Ask for Bulletin API/849. EC01ITH0 6 Tne Kontro Company. Inc., Orange AAA 01364, Telephone: 617-544-2536 Circle 21 on Reader Service Card CHSM! rAt. ENG!KSESllNG OCTnBEl. T. 1W not be used above 150C. Jan Dahlgren, technical specialist with the group, says that although manufacturers claim that their products will withstand much higher temperatures, tests have shown they don't always meet require ments, especially with sudden steampressure surges up to 15 bar. Hans Wemborg, technical specialist with the Swedish Assn, of Chemical Industries, adds that expanded graph ite gaskets are brittle and hard to han dle, especially for large flanges. He notes that flanges used for batch cook ers in pulpmilis car. be as big as 3.5 m dia. PTFE has "unequaled" chemical re sistance a? a gasket material, a tem perature range front -460`F to 500'F. and good dielectric strength and impact resistance, according to David Lingard. manager of applications engineering with Gariock. However, it has poor wear resistance and a tendency to creep relaxation or cold flow. The latter can be reduced, he says, by using fill ers, such as glass or carbon fibers, bronze, ceramics or barium sulfate. However, expanded PTFE has only 17-607 creep relaxation, compared to as much as 400/7 for full-density PTFE gaskets, claims Roger Davis, of W. L. Gore & Associates (Elkton, Md.). Gerald Parkinson. Contributor: Rob ert Skole, McGraw-Hill World Mews (Stockholm) Study tracks energy to the year 2000 In a new study. `'World Energy Outloot: Tnrougr. 2000," Conoco {Wilming ton. Del.,), the Du Pom subsidiary, ar rives at conclusions that have wide implications for the energy industries ir. the I'.S. and worldwide. For example, the firm predicts that crude-oil and petroleumproduct ports will rise from 267 o; f'.S. d?; in 19S5 to 4151 by 1990. and 567 b; turn of the century. That means nearly 11 million hbl will be bro into the U.S. daily in the year 2000. pared with just over 4 million ir. OPEC's share of world oil suppli expected to reach 607 by 2000, up: 387 in 19S5, the study predicts. Noting that the world's oil resare concentrated in regions having nificant potential for supply dh tions. Conuco's outlook warns that ing import dependence means: ( higher risk of economically darr.a. shortfalls. (2i reduced flexibility if. r.tiatir.g and imjdemeuf.ng for policy, and (3- greater military ob tions to safeguard vital supply l;n A: the same time, the ability to res; with ar. increase in domestic sup; will become greatly diminished. .= trie report. TAKING THE MIDDLE COO -- In its f Expert Answers to Tough Separation Problems M!St AtASTER trie ACS Mist-Waster allows higher gas caDacm tuan conventions: nrs*. pads due lo its improved iiouid orainage. Gat caoarm increased up to ICXH are provioed Liquid loading capacity increases up to 10 times Reduces pressure drop down bv 50% txienos Service trie Hiphe- Efficiencies VAST MISt ELIMINATOR ACS Plate Pal. minimizes oiuggage in gas streams containing suspended soiias oi viscous, sucks particles. 99% efficiency on particles down to 10 micron Available in several styles, metal or plastics LIQUID-LIQUID COALESCERS ACS Coaiescei designs come in both mesh and plate type configurations. Mechanical separation ol two immicibie liouids Flow rates uo to 1000 CPM Equally efficient with an\ hyorocaruon watei combination TRAYS AND TOWER INTERNALS AC< Industries supplies a wide range o' tra anc tower internals. Valve - Bubble Cap - Sieve 1 ras < Complete iine or supports anc distributors High efficiency structured packing OVER THIRTY YEARS EXPERIENC VAN! M'S' '|IMWAK>fc f 1 CJTnduSTRIES.imc I 1420S Industry Re Houston. Texas 77053 (7l3i 434-0934 1-800-231-0077 Telex 76 2587 Telefax.: (713> 433-620". Circle 22 on Reaoer Service Card 26 CHEMICAL ENGINEERING 'OCTOBER IT. >9-