Document gbEz3jdmbQw9nQew7D1N8kYrG

c CiM^AN'V (EKB-e-76; TO D. R. Keck FOR: S. E. Hcheer FRO id E. L. Bu m a r. RE: PVC PLent uPP Compliance - Carbon Adsorbers DATE: August 2C, 2??r' , A. study ha? r a = r. rads to recortsnd carbon adsorber requirements for the P'YC Plan: extension. This study was made using the existing adsorbers manufactured by Chemical Design, Inc. (CDI). Material and mechanical flow sheets based on the CDI concept ware prepared. However, this type of unit has some serious deficiencies which can adversely affect the ability to consistently jadsorb VCM to or below 10 ppm. The findings of this study show that with the GDI design: . Carbcr. bee capacity is approximately pounds of organic material per IOC pounds of carbon with inlet organic concentration varying The amount c: residual moisture cn the bed during the aasorptiqn cycle is very important, (This is a major deficiency in the CD|l unit). Toe much water decreases the carbon capacity. Too littfLe water does not give an adequate "neat sink" for the heat of adsorption and the bed temperature gets too high. . The drying system requires a very large volume of nitrogen to bet recirculated. The existing unit never gets completely dry*. E.ECOMME'dTlDh'1 Tne results of this study show that heat of adsorption and drying are very- important. For maximum bed capacity, trie bed must be completely dry- but must remain cool throughout the acsorprion cycle. Tne existing CDI beds dc nor meet these requirements. Hence, this writer recommends that th^y be dropped from furrier consideration unless CDI can design a system td meet the following recommendations. 1 To achieve the goal of dry, cool beds, the new adsorbers should incorporate the following: Vacuum stripping with simultaneous internal high pressure steam heat via heat exchange. COLORXTE 017691 Kec Aurusr :Cj IS 76 The adsorbers described bv Mr. J. H. Jacob ir. his memo "VCM F.enrvalj Via Carbon Adsorption: Research-Cottrell Lesiur.1'. June 1-., 1976 , appear to incorporate the above mentioned lectures. Hence, this writer recommends that P.esearcb.-Cottrell be considered as a p: ter. rial supplier c; our! new adsorbers. _ i None of the equipment on the existing unit is star sequence control valves have beer, provided with 17 Hence even s~all repairs require a r: relate strut do shutdowns ir. the new unit, all Meier pieces c: equ spare, and ail sequence valves should be cl.thed w Lso. none olf the '.Z 3vrid :re|C'jent DISCUSSION A three month study was made of the existing PVC Plant carbon adsorbers. During this period, the unit was down almost one-third of the time (due to mechanical problems. The unit was off-spec (above 10 ppm VCM in thp vent) about one-third of the time, and on-spec the remaining one-third of! the time. Much of the downtime was caused by a bearing problem in the regeneration biow'er. However, some downtime was for minor repairs which because! of the., economy design, could not be made without a complete shutdown which;requires a day to purge the system prior to opening the equipment, and a day to purge air out of the system prior to putting it back on-line. If appropriate block, valves wTith bypass valves and spare eruirrer.c had beer, installed, much of this downtime could have been prevented. Problems of high stack analyses were found to have two major causesH One cause was a heavy loading of toluene fed to the adsorbers during nitrogen stripping of the slurry tanks.. The other problem is an improper relation ship between bed moisture content and bed capacity and/or bed temperature. When toluene is adsorbed on the beds, it is extremely difficult to remove to a low enough concentration to allow adequate VCM adsorption with the existing regeneration system.- This problem, however, car. re eliminated by using steam stripping of the slurry as is the current plan. ! The relationship between bed moisture content and VCM concentration in the adsorber vent was found to be very important. Under iscthermal bed Conditions, VCM concentration in the adsorber vent wTill decrease with a corresponding decrease in moisture content of the bed. However, because of heat ojf adsorption of VCM on carbon, a bed temperature rise is experienced. : The magnitude of this rise can be large enough to be detrimental to the bed efficiency. Because of the high heat capacity of water, any w'ater op the bed acts as a "heat sink" to minimize this temperature rise. Hence, there exists an important balance between Tnpj_g11-i~jm contsnt .nd bed Although this optimum moisture content was not evaluated, the stuaiefe did indicate that there exists a very narrow range of moisture where 10 ppm VCM in tne vent can be met. Based on these findings, a unit which incorporates internal cooling and very dry carbon would appear to be much mm re reliable than the existing unit. LKB-5-76 "Removal Of Toluene From Carbon Adsorbers", June 28, 1976, COLORITE 017692 TO: D. R. Keck -o- Augus t 2C 19 7c Mechanical anc material flow sheers based or. the existing CDI svstem. were prepared and are attached. As mentioned in the recommendation section of this report, this design is not reconmendec. The feed data, however, presente ir. the material flow sheet car. be used for other VCM ret,oval designs. The reader will note that there is real or deviation from thee CD! dssi that a third bed has been added. This third bed has dual purpose: (1; it will allow changing of the carbon without removing the entire unit iron: service, and (2) it allows rrimarv ar.d a seconder'.- adsorption bee. to - LKB/cjm Attachments D. C. Coldiron R. E. Harmona C. E. Crain L. L. Bird A. p # Gutierre: J. R. Jacob E. J. Schuetz P. J. Patel P. A. Lobo G. I. Rozand E. J. Hourihan S. R. Madan J. Sandstedt L. K. Burraan COLORITE 0X7693 Getting out ths last traces of VCM Tenneco Drocess uses activated carbon to remove vinyl chloride monomer from PVC plant gas streams. It's one of several methods producers are licensing lid.:.', exntirimc; uitr. m z: `.nere ua n, e-Ucncr c rrt.or, meihoO oi ayntreiime y ir."' \:r C",'. ' id; rrni.sitQns fretr r>oi^ s v! s;rTt ' :. .,:-.c:-...v.ivr, it t:.s a: u- '.ror :nt car nor. : Cf 7 , -n:.- :.a' convinced Tcr.nectr". S jddit brook. N.J ) tha! it Tn u h;c:. t Stmts' Aside from `Ut. sr-iart^rcr.' in to keep to r mi tuz ney. route So r. i- yetting 'i1.;:<s points w.ieri y y ;> , `.mu r.einoc U' C'liiSTe \ r\- e ,ar: 're atme-m: er. a T L .---cjL-ir.i rTw-r>. c " re tz . r ; ".c: / *. r.. - : ' . :' \ r - ' c. - -r: S Mike: mat.^er o' - . tne tarr. nac t< cc r tjrt nc-ioey to coniroi emi- p\: Z ' w " N J i. nicues i,,f lt - ;1 ir Zv Generally, tr, v.'iZ3Ljcr il-li tntst processef .,iOn- \ OVv f :> n.arkeuns tne know-now VCM and the polymerization initiator ir U.S and in Eurontar courttrie? that are follow me tne U.S. lead in setting are ci: nersec ir. waier bv the use cf su_Dcndmst or emulsifying agents. The poly stringent emission standards. merization temperature ts selected to ob The firm is just one of a number of tain the desired molecular weight. But U.S. producers that have developed li not aJl of the vmvl chloride is converted censing packages in an effort to recoup into PVC. Usually 17-20T of monomer pan of ttie million; me) have spent to de that does not tea:: '--mams at the end cf velop trie nev technology tne pe.Knisrtzauor cveie Much o; tna: B.F Goodrich is licensing ns steam- can be recovereo and recycled to the stripping process, which removes VCM from end of the process But as much as from PVC suspension icsms Diamond Snamroc) h-v- Ge.eiopec a pronnetar1. li-c.cnicur ice rerr.oy mg resiGuai \CM U from PVC dupersion resins Monsanto has been licensing its PVC reactor clean ing know-how for more than a year. Lonza (Basle! Switzerland) is offering a procedure for preventing suspension resin polvmer buildup on reactor walls. And several others have developed . in strumentation to monitor the amount of VCM :r. the air and in PVC Thirst' Carbon.- Tenneco`s develop ment is aimec at recovering the residual VCM in vent gas streams (CM', Sepi. 18, 1974, p 66) A unit built by Chemical De sign (Lockper. N'.Y.j was installed at Tenneco ; PVC riant m Pasadena. Tex., in earn !97i _ A year s experience with the equips mem, saw- Ro\ T Gottesman. associate direcior of research and development. show-s that less man 4 ppm of vmvl chlo- 7f_G=~' mm S*r*-*Li ___ 5 TENNECO'S GOTTESMAN New process cuts PVC plants' VCM ipss to beiow 4 purr, ride monomer is escaping in the adsorber effluent strearr. Dunne tnal time, the ac tivated carbon in tne unit has undergone more than 1.300 adsorption and regener ation cycles That makes it good enough to meet the proposed Environmental Pro tection Scenes standard of 10ppm. More:.-::, a..:: K months of com:;,, uous service, samples of carbon with drawn from the adsorber showed that it retained 90'ir of :L- original adsorptive ca- 4% VCM car, remain ;n tne PVC Slum from the reactor. That can be removed b\ specialized stripping techniques, such as the ones Goodrich. Diamond Shamrock and Tenneco now offer. Residua; VCM Goer that cieanur pr.aie is one of im pc'.er,tiai sources of feed for the carbon acsorption siep. Another source is the slurry tanks, where operators flush air or nitrogen ff.r.'uch the vapor Space of the uni. i, re.-: VCM concenuiauons cown and sityen: - ff,amiridbie mixture from formine lj.-pending on the level of stnppma of the >.-rr) downstre4m. VCM concentre, t-or. ;r f;e nitroaen ipuraed may reach l11 u- eucirmeit: ir the process :> p-'iec v H!" mqr; car it. reauce the e' . r ar.src ar.^j it icmoye the las. trace- cf \ CM T^iese off-gas puree s:reams generally contain 10-30 moi pet tirn: vinyl chloride j New Twist: Vinyl' chloride has been around a long lime and so has activated carbon But up to nqw, researchers have worked with pure ifionomer. Tenneco's contribution has beefi to make the pro- cesx y'ork with recovered vinyl chloride, sav? Gottesman He , explains that this material can contain : residual-iwuaiors, catalyst fragments, and suspending agents, so that it is pjone to polymerize and foul the carbon svjuem Making the process work is a mailer of se.ictmg the right operating conditions and the nght type of activated carbon Another method of scrubbing VCM from stack gas, called oxyphotolysis, has been investigated by Robintcch of Fort V.- orth. Tex. (C W Technology Newsletter Juh 9. 197S). The firm says it is still eval uating the economics, of installing the uniL which so far has n|ot been used com mercially Ait.nougn caroon adsprpuon is the pro cess that GotlesmaD believes will .attract the widest interest, the company is arm ing itself with a vanejy of other tecn- noiogy "V t have filed 13 patent appli cation^ or. wide!) differing subiectsf" sav- Gottesman. "They include a spray appa ratus for cleaning PVC reactors, processes for removing VCM froth suspension and emulsion processes, thp destruction of VCM by ozonolvsis an(3 the removal of monomer from dispersipn latex by spar- gmg " If others' experience ^s any indication, there is a big demand fcjr the know-how. B.F. Goodrich Chemical says it has signed agreements with (six corporations in Sweden. Italy. Japan jand the U.S. for tti suspension-resin stnpjung lechnoiogy. Diamond Shamrock bpcame a licensor in March, offering its proprietary tech nique for removing residual VCM from August 11, 1976 CHEMICAL WEEK 35 Ji -- ;----A' - a---- WTf CC ^:.r5w COLOR!TE 017694 You can have plenty; get it fast! Aminate reacts with acids ro generate carbon dioxide and pro duce solutions of the correspond ing salt. It s used in the manufacture of isirazene.an ingredient for smail arms primers. Further applications, in pnotograonic emulsions a20 dyes oferylation of animal sxins, textue softening agents, flameproofing agents. Also as a blowing agent in manufacture of foam as a vinyl sta bilizer, and in the preparation of aminoplast resins. Let your chemical imagination ream. Find all the uses you '.van: because we nave all tne Aminate you could want. Available as a fine, white, odorless crystalline powder Delivery is fast. The price is right. For full details, write tocay tc the IMC Chemical Group, inc., Sobin Park, Boston. Mass 02210. line eg cHemicfli GftOURinc. CSC INDUSTRIAL CHEMICALS DIVISION A suosioiafy of l^nterna^pona, Mtr*ifa*s & Cnenvcai C-C'cc'S' o~ 36 CHEMICAL WEEK Aupust 11, 1976 dispcrsior Ttsituj Difi.ertr'. tecnmcuts are rcomrrd for ihe tv : s-r.rns or;a\ji: of differmeet m particle sice The comb an;- fyni'-TV f.-.;'. :r. '.tie su- pension mores;, .mcint'tr.er nrcp'ev.- si;-- nenced ir. water It;- p.i-b; rare : ' t panicles ranging jir. sicr itojt 9-, t. . _'. microtis ir. the ld>prTo' t-r .. r rrocess. a ct'ii d..:e'..\ - c i net droplets cetpe; 5'VC : .."-.Ur , r aping 0 f mirror., ir. sir; Tv_->-. ranicies art more ser-Stme r.er mechanica' disturbance t.-?.r <.: cl resins, into d.ffjren: tvtrr, .vt" me 11 outs;;se- V, r _ r-:' ' f TV.oriie s;r'. um;, :r.'re;'i` G v:imt irorr, outside tne U S \\ ;: c; " in ; iTioment r,a\elans beers h'ji r Te lativch new onfer " It seems doubtful tne; an;. O'*! c w: ' :. a financial bonanza from t ns n c i c nologv. Rainer, licensors see iheir effort as one of trying jto recover pan of their development cost). Diamond Shapiroci adds "Liu;"' t; this find of teLtihoiogv is not gome u : . a giant mone\-maker for-aftybodv as w as we can sec ofice vou nut the income generated ur attdins; what it cost to de velop 11 in t.it first puce V\ e nc:w. v . will be able to da:ra_\ cur de-eicurr i n.- costs--that is, spraaa mem out truougr. me industry." , Insight into energy A new 900-pag|e United Nations studs of energv use his turned up extensive data on the use a^id distribution of com mercial energy since 1930 Among the findings ; The U.S.. wtjth 5f,7 of tne wmlc . population, used i)05c of the world's com mercial energy iijt 1974. compared with 45% in 1950. Its per-capua gasoline cor- sumouon was nifie times the world asr- age. The U.S-S.Rf., the world s second- largest user, increased its share firm 11.5% in 1950 to l|6.6%in 1974 China and Jgpan arc the third- and fourth-largest consumers, respective!;. China still relies plainly on solid fuel. Ja pan is a leading importer of ali types of energy'. , The report updates earlier studies on commercial energy production, trade and consumption anp includes prehrr.mip data on tne prodbcticr. of pr.rr.ip '. fuels for 197;. I It is available from the UN Sales Sec tion (New York) for S30, COLORITE 017695