Ukuqonda Inqubo ye-Vinyl Chloride Monomer
I-vinyl chloride monomer (VCM) imele njengesisekelo semboni yepulasitiki yesimanje, ihlinzeka ngezakhi ezibalulekile zokukhiqizwa kwe-polyvinyl chloride (PVC). Njengekhemikhali yezimpahla, i-VCM isetshenziselwa kuphela i-PVC polymerization, evumela ukukhiqizwa kwayo yonke into kusukela kumadivayisi ezokwelapha nezinto zokwakha kuya ekumbozweni kwezintambo kanye nezimpahla zabathengi. Isidingo se-VCM sihlobene eduze nomkhiqizo we-PVC womhlaba wonke, okwenza ukukhiqizwa kwayo okuphephile, okusebenzayo, nokuphephile kubaluleke kakhulu kwezimboni.
I-VCM iyigesi engenambala, evutha kakhulu ezimweni ezizungezile, evame ukuphathwa njengoketshezi olucindezelwe ezindaweni ezikhethiwe. Isakhiwo sayo samakhemikhali, i-CH₂=CHCl, sakha iqembu le-vinyl elixhunywe kwi-athomu eyodwa ye-chlorine. Lokhu kuhlelwa kwama-molecule kuvumela i-polymerization elula, isici sokusebenza esisekela ukusabela kwe-polymerization ye-vinyl chloride ebalulekile ezinyathelweni zenqubo ye-PVC polymerization. Izakhiwo zomzimba ze-vinyl chloride ewuketshezi—njengephuzu lokubila elingu-−13.4°C kanye nobuningi obungu-0.91 g/mL ku-20°C—zidinga ukulawulwa kwenqubo okuqinile kanye nezinhlelo zokugcina ezikhethekile ezigcina i-compound njengoketshezi lwemisebenzi yenqubo yokukhiqiza i-vinyl chloride monomer engezansi.
Inqubo ye-Vinyl Chloride Monomer
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Ukusetshenziswa kwe-VCM ngaphandle kobubanzi be-PVC akunamsebenzi, kugcizelela indima yayo njenge-monomer ezinikele yokwenza i-polymerization. Ngenxa yalokho, zonke izici zomklamo wesitshalo se-vinyl chloride monomer, kusukela ekwakhiweni kwesitimela se-reactor kuya kumkhiqizo.ukuhlanzwakanye nokutakula, zilungiselelwe ukuguqulwa okukhulu, okuqhubekayo ukuze zinikeze ubuchwepheshe be-PVC polymerization.
Kodwa-ke, ukuphathwa nokugcinwa kwe-VCM kubeka izingozi ezinkulu. I-VCM ihlukaniswa njenge-carcinogen yeSigaba 1, enobufakazi obuqinile obuyixhumanisa ne-hepatic angiosarcoma kanye neminye imiphumela emibi yezempilo ngemva kokuchayeka isikhathi eside. Iphrofayili yayo yobuthi iyandiswa ngokwakhiwa kwama-metabolites asebenzayo, ahlanganisa ama-macromolecule eseli futhi aphazamise izinqubo zebhayoloji. Ukuchayeka okukhulu kuholela ekucindezelekeni kwezinzwa, kuyilapho ukuchayeka okungapheli emsebenzini kuhlotshaniswa "nesifo sabasebenzi be-vinyl chloride" - isifo esihlanganisa ukulimala kwesibindi, izimpawu ezifana ne-scleroderma, kanye nezilonda zamathambo. Imikhawulo yokuchayeka elawulwayo iqinile: kusukela ngo-2024, i-Occupational Safety and Health Administration (OSHA) ibeka umkhawulo wokuchayeka ovunyelwe wamahora angu-8 ongu-1 ppm, kanye nemingcele ephansi ngisho nangokwengeziwe enconywe yi-ACGIH kanye ne-NIOSH ukuze ibonise ukuqonda okuthuthukayo kobuthi.
I-VCM nayo iyasha kakhulu, inezinga lokuqhuma eliphakathi kuka-3.6% no-33% emoyeni. Ukuhlanganiswa kobuthi nokusha kuholele ezindleleni zokuphepha eziqinile kuzo zonke izikhungo zokukhiqiza i-VCM. Imigqa yenqubo ivalwe ngokuphelele futhi igcinwa ngaphansi kwesimo sezulu esingenawo umoya—ngokuvamile i-nitrogen—ngokutholwa kokuvuza okuqhubekayo kanye nezinhlelo zokungenisa umoya eziphuthumayo. Umoya wokukhipha umoya endaweni, ukuvalwa kwenqubo, ukuvinjelwa kwamalangabi avulekile, kanye nezindawo zokufinyelela ezilawulwa ngokuqinile kunciphisa ingozi. I-VCM yoketshezi igcinwa futhi ithuthwe ngaphansi kwengcindezi emathangini amelana nokugqwala, ngokuvamile iqiniswa ngezithibi ze-polymerization ezifana ne-phenol ukuvikela ukusabela okuyingozi okuzenzakalelayo.
Izindlela Eziyinhloko Zokukhiqiza ze-VCM
Ukukhiqizwa kwe-VCM kuphethwe izindlela ezimbili zezimboni: i-chlorination eqondile kanye ne-oxychlorination. Zombili zijikeleza ekukhiqizweni nasekuguqulweni kwe-ethylene dichloride (EDC), okuyi-principal intermediate eqhekeka ukuze iveze i-VCM.
Endleleni yokukhipha i-chlorine ngqo, i-ethylene isabela negesi ye-chlorine enqubweni yesigaba soketshezi esishisayo kakhulu, ngokuvamile phezu kwe-ferric chloride noma i-catalyst efanayo ukuze ikhiqize i-EDC nge:
C₂H₄ + Cl₂ → C₂H₄Cl₂
Ngaphandle kwalokho, inqubo ye-oxychlorination ihlanganisa i-ethylene, i-hydrogen chloride, kanye ne-oxygen isebenzisa i-catalyst yethusi (II) chloride, ekhiqiza i-EDC namanzi:
C₂H₄ + 2HCl + ½O₂ → C₂H₄Cl₂ + H₂O
Le ndlela inikeza izinzuzo zokuguquguquka kwezomnotho kanye nokwe-feedstock ngokuvuselela i-HCl ekhiqizwe ngesikhathi sokukhiqizwa kwe-VCM, obekungadala izinkinga zokulahlwa kwemfucuza.
Uma i-EDC isihlanganisiwe, ihlushwa ukushisa cishe ku-500°C, ngokuvamile esigabeni somusi phezu kwe-pumice noma ukupakisha kwe-ceramic, ukuze kukhiqizwe i-VCM kanye ne-hydrogen chloride:
C₂H₄Cl₂ → CH₂=CHCl (VCM) + HCl
Umkhiqizo we-VCM ophuma esithandweni sokuqhekeka uxutshwa nengxube eyinkimbinkimbi yemikhiqizo engaphansi kanye nezitsha zokudla ezingaphendulwanga. Izigaba eziningi zokuhlanza—ikakhulukaziukuhluzwa— zisetshenziselwa ukuhlukanisa, kugxilwe kakhulu enqubweni yokuhlanzwa kwe-vinyl chloride monomer. Ukusebenza kombhoshongo we-VCM distillation kanye nezinhlelo zokuhlanganisa ukushisa ezihambisanayo zenzelwe ukukhulisa ubumsulwa (ngokuvamile >99.9%), ezibalulekile ekupholiseni kwe-PVC kwekhwalithi ephezulu. Amamitha okuqina angaphakathi njengalawo akhiqizwa yi-Lonnmeter avame ukusetshenziswa ukuqapha ukuqina koketshezi lwe-VCM emazingeni okushisa ahlukahlukene, okusiza opharetha ukuthi babone ngokushesha ama-batches angaphandle kwe-spec noma izehlakalo zokungcola.
Izitshalo zokukhiqiza zithanda izakhiwo ezihlanganisiwe ezihlanganisa ama-reactor e-chlorination eqondile kanye ne-oxychlorination, ukuvuselelwa kabusha kwe-hydrogen chloride okuhlanganisiwe, kanye namasu okubuyisa amandla. Lezi zakhiwo ezihlanganisiwe zisekela izindleko eziphansi ze-feedstock kanye nokusetshenziswa kwamandla okuthuthukisiwe. Ubuchwepheshe benqubo ye-vinyl chloride monomer obusesikhathini bulwela isivuno esiphezulu, ukuphepha, kanye nokuguquguquka ekusingatheni izimfanelo zezinto zokusetshenziswa ezahlukahlukene, kuyilapho ukuqapha okuqinile kwezakhiwo ezibalulekile (kufaka phakathi ubuningi kanye nobumsulwa) ezindaweni ezahlukene zenqubo kuqinisekisa kokubili ikhwalithi ye-PVC kanye nokuhambisana nomthetho wezempilo, ukuphepha, kanye nemvelo.
Ukugeleza Kwenqubo Eningiliziwe Kokukhiqizwa Kwe-Vinyl Chloride Monomer
Umdwebo Wokugeleza Kwenqubo Yokukhiqiza I-Vinyl Chloride
Ukukhiqizwa kwe-vinyl chloride monomer (VCM) yesimanje kuncike ekugelezeni kwenqubo okuhlanganiswe kahle, okuvame ukubonakala ngomdwebo ophelele odweba isinyathelo ngasinye esibalulekile. Inqubo iqala ngokufaka izinto zokusetshenziswa—ikakhulukazi i-ethylene, i-chlorine, i-hydrogen chloride, kanye nomoya-mpilo. Ngaphakathi komklamo wesitshalo se-vinyl chloride monomer, lezi zinto zihanjiswa ngokusebenzisa ama-reactor e-chlorination aqondile kanye ne-oxychlorination ukuze kuhlanganiswe i-ethylene dichloride (EDC), okuyi-intermediate ephakathi.
Ekukhiqizeni i-chlorination eqondile, i-ethylene isabela ne-chlorine ngaphansi kwamazinga okushisa alawulwayo (40–90°C) ukuze ikhiqize i-EDC. Ngokufanayo, iyunithi ye-oxychlorination ihlanganisa i-hydrogen chloride (evame ukuphinda isetshenziswe kusukela ezinyathelweni zenqubo zakamuva), i-ethylene, kanye nomoya-mpilo—kusetshenziswa i-catalyst esekelwe ethusi emazingeni okushisa aphezulu (200–250°C) ukuze kukhiqizwe i-EDC namanzi. Zombili izindlela zokusabela zihlanganiswa ukuze kusetshenziswe kabusha amagesi angaphenduliwe futhi kuthuthukiswe amazinga okusetshenziswa, okwakha umongo wenqubo yokukhiqiza i-vinyl chloride monomer elinganisiwe.
Ukuhlanzwa kwe-EDC eluhlaza kuhilela izinsika zokuhluza ezisusa amanzi, imikhiqizo ye-hydrocarbon e-chlorine, kanye nokunye ukungcola. I-EDC ehlungiwe ibe isiphakela i-pyrolysis, noma i-cracking, isithando—inqubo esebenza ku-480–520°C kanye nokucindezela okulinganiselwe. Lapha, ukubola kokushisa kukhiqiza i-VCM futhi kukhiphe i-hydrogen chloride, evame ukubuyiselwa ku-oxychlorination loop. Ukucima nokupholisa ngokushesha kwamagesi aqhekekile kuvimbela ukusabela okungafuneki eceleni futhi kunciphisa ukwakheka komkhiqizo oyingozi.
Umfudlana wegesi ophumayo uyahlukaniswa futhi uhlanzwe kusetshenziswa amakholomu e-distillation engeziwe kanye nabahlukanisi besigaba. Amasu azinikele okuhlanza i-VCM, okuhlanganisa ukuhluzwa kwezigaba eziningi kanye nokumuncwa, aqinisekisa ukuhlanzeka komkhiqizo ngokuvamile kudlula u-99.9%. I-EDC engaphenduliwe eguquguqukayo iyasetshenziswa kabusha, okwenza kube ngcono ukuguqulwa ngenkathi kunciphisa ukukhishwa. Izinhlelo zokulawula eziqinile kanye nokuqapha njalo izinqubo kuvikela ekuvuvukeni futhi kuqinisekisa ukuhambisana nezinqubo zokuphepha ze-vinyl chloride evuthayo, ebangela umdlavuza.
Kuyo yonke inqubo yokukhiqiza i-vinyl chloride monomer, ukuphathwa kwamandla kanye nokubuyiselwa kokushisa kubalulekile ukuze kuqhubeke isikhathi eside. Ukushisa kwe-exothermic okuvela ku-chlorination kanye ne-oxychlorination kuyabanjwa futhi, kufudunyezwe kusengaphambili izitsha zokudla zesikhathi esizayo noma kukhiqizwe umusi wenqubo. Ukuhlaziywa kwe-pinch kanye namasu okuhlanganisa ukushisa kusetshenziswa kuwo wonke amanethiwekhi okushintshanisa ukushisa, kunciphisa ukusetshenziswa kukaphethiloli kanye nomthelela emvelweni.
Amapulatifomu okulingisa inqubo—ikakhulukazi i-Aspen Plus—abalulekile ekwakhiweni, ekukhulisweni nasekusetshenzisweni kahle. Lawa mamodeli edijithali alingisa izilinganiso zezinto, i-kinetics yokusabela, ukuziphatha kwesigaba, kanye nokugeleza kwamandla kuzo zonke izinyathelo, okuvumela ukuqinisekiswa okusheshayo kokusebenza kwesitshalo ngaphansi kwezimo ezahlukahlukene. Ukusebenza kahle kwamandla, isivuno se-EDC-to-VCM, kanye nemithwalo yemvelo kulungiswa njalo kusetshenziswa idatha yokulingisa, kusekela imigomo yezomnotho kanye neyokulawula yobuchwepheshe benqubo ye-vinyl chloride monomer ethuthukisiwe.
Imisebenzi Ebalulekile Yeyunithi Esitshalo se-VCM
Ukuhlanganiswa Nokuhlanzwa kwe-EDC
Ukwenziwa kwe-EDC kusebenzisa izindlela ezimbili zokusabela ezihambisanayo—i-chlorination eqondile kanye ne-oxychlorination—nganye inezidingo zokusebenza ezihlukile. Ekuchlorination eqondile, ukuxubana okulawulwa kahle kwe-ethylene ne-chlorine kwenzeka ku-reactor yesigaba soketshezi, ngokulawulwa kwezinga lokushisa ukuze kugwenywe ukwakheka ngokweqile komkhiqizo ongaphandle. Uma ishiswa nge-exothermically, le reactor idinga ukupholisa okuhlanganisiwe kanye nokuhlukaniswa kwesigaba segesi ukuze kuvikelwe ukusebenza kahle kokuguqulwa.
I-Oxychlorination isebenzisa i-reactor enemibhede eqinile noma enombhobho omanzi, isebenzisa i-catalyst ye-chloride yethusi esekelwa ku-alumina. I-Ethylene, i-hydrogen chloride ephinde yasetshenziswa, kanye nomoya-mpilo kuyahlanganiswa futhi kuhlangatshezwane nakho ku-200–250°C. Le nqubo ikhiqiza kokubili i-EDC kanye nomhwamuko wamanzi. Ukulawula izinga lokushisa ngokucophelela kanye nokulinganisela kwe-stoichiometric kunciphisa imikhiqizo eyingozi ene-chlorine.
Imifudlana ye-EDC eluhlaza ehlanganisiwe evela kuzo zombili izindlela ihlanzwa ngezigaba. Izinyathelo zokuqala zisusa amanzi akheke ngesikhathi se-oxychlorination ngokuhlukaniswa kwesigaba kanye nokuhluzwa. Amakholomu esibili akhipha ama-compounds alula (njenge-chloroform) kanye neziphetho ezisindayo, okuholela ekuhlanzekeni kwe-EDC okufanelekela i-pyrolysis esebenza kahle kakhulu. Ama-loop aphinda asebenzise kabusha abuyisa izinto ezingaguquliwe kanye nemikhiqizo elandelanayo, okwenza ngcono ukusetshenziswa kwezinto zokusetshenziswa kulolu hlobo lokucushwa oluvaliwe.
Ukuqhekeka Okushisayo Kube Yi-Vinyl Chloride
Ukuqhekeka kokushisa, noma i-pyrolysis, kuyisithiyo sokukhiqiza i-VCM. Lapha, umhwamuko we-EDC ohlanzekile kakhulu ushiswa ufike ku-480–520°C ngaphakathi kwesithando esishubhu, uvame ukushiswa ngokungaqondile ukuze kuqiniswe amazinga okushisa futhi kugwenywe izindawo ezishisayo. Lokhu kusabela okuphezulu kwe-endothermic kuqhekeza i-EDC ukuze kwakheke i-vinyl chloride monomer kanye ne-hydrogen chloride ngendlela ye-free-radical mechanism.
Izinguquko ezibalulekile zenqubo—izinga lokushisa, isikhathi sokuhlala, kanye nengcindezi—zithuthukiswa kusetshenziswa izinhlelo zokulawula izinqubo ezithuthukisiwe kanye namamodeli okulingisa. Amazinga okushisa aphezulu angakhuthaza ukungcola kwe-polymeric kanye nokwakheka komkhiqizo olandelanayo njenge-tar noma ama-compounds aqinile e-chlorine. Ukucima okusheshayo ngokushesha ngemva kokuqhekeka kumisa ukusabela okungekuhle futhi kufinyeze izingxenyana zomkhiqizo eziwusizo. Ukuhlaziywa kwenqubo kulandelela ukukhiqizwa kwe-HCl, okuvame ukubuyiselwa futhi kubuyiselwe ku-oxychlorination.
Ukuhlanzwa kwe-VCM kanye nokuhluzwa
Ukuhlanzwa phansi kubalulekile ekufinyeleleni ubumsulwa obuphezulu be-vinyl chloride monomer. Ukuhlukaniswa kwegesi noketshezi kususa amanzi kanye nezinsalela ezisindayo ngaphambi kwamakholomu amakhulu okuhluza. Inqubo yokuhluza i-vinyl chloride monomer isebenza ngaphansi kokulawulwa ngokucophelela kokucindezela nokushisa, okuqinisekisa ukuhlukaniswa kwe-EDC, i-HCl, kanye ne-azeotropes engaphenduliwe nezinye izinto eziphilayo ezifakwe i-chlorine.
Izilinganiso zokucindezela kwekholomu kanye ne-reflux zilungiselelwe ukulinganisela ukusetshenziswa kwamandla ngokumelene nemigomo yobumsulwa—i-reflux ephezulu ithuthukisa ukuhlukaniswa ngezindleko zomusi kanye namandla okupholisa. Izinhlelo ze-condensation eziningi kanye ne-reboiler zithuthukisa ukusebenza kahle, ikakhulukazi uma zihambisana nokubuyiselwa kokushisa okuhlanganisiwe.
Ngaphandle kokuhlukaniswa ngokomzimba, amasu okulawula inqubo athuthukile avumela ukulungiswa kwesikhathi sangempela ezimweni zekholomu, ukuphendula ekushintsheni kwe-feedstock noma izehlakalo ezingacacisiwe. Ukuhlolwa kwengozi yobuningi kusekela ukuphepha kokusebenza, kusekela ukutholwa kokuvuza kanye nokunciphisa ukukhishwa okubalulekile kwalesi sikhemikhali esiguquguqukayo. Ukusetshenziswa kwezixazululo zokulinganisa eziku-inthanethi, njengemitha yobuningi kanye ne-viscosity evela eLonnmeter, kunikeza ukuqapha okunembile, kwesikhathi sangempela okubalulekile kwekhwalithi yomkhiqizo kanye nokusebenza okuphephile.
Izakhiwo Ezibonakalayo Nezamakhemikhali Ezihlobene Nokukhiqizwa Kwe-VCM
Ubuningi be-VCM Liquid kanye nokuphathwa kwe-VCM Liquid
Ubuningi boketshezi be-VCM buyahlukahluka kakhulu ngokushisa kanye nengcindezi—into ebalulekile yokusebenza ekuphatheni nasekugcineni i-vinyl chloride monomer. Ezimweni ezijwayelekile (20°C), ubuningi be-vinyl chloride monomer buvame ukubikwa njengo-0.911–0.913 g/cm³. Njengoba izinga lokushisa likhuphuka, ubuningi buyancipha, okuthinta amazinga okugeleza kwe-volumetric kanye nokubalwa kokugcinwa kwethangi.
Isibonelo, ku-0°C, ubuningi bungakhuphuka bufike cishe ku-0.930 g/cm³, kuyilapho ku-50°C busondela ku-0.880 g/cm³. Izinguquko ezinjalo zidinga ukulinganiswa kabusha kwemishini yokudlulisa kanye nokuqapha ngokucophelela inqubo, njengoba ukushintshashintsha kuthinta izinyathelo zenqubo ye-PVC polymerization ezansi. Amamitha obuningi boketshezi angaphakathi kwe-Lonnmeter avame ukusetshenziswa kulezi zisekethe ukuze kuqinisekiswe okuqhubekayo, asekele ukulawulwa kwempahla kanye nokudluliselwa kokugcinwa ngokunikeza ukufundwa okusheshayo kuzo zonke izimo zenqubo ezishintshayo.
Izici zokuncibilika kwe-vinyl chloride ewuketshezi nazo zibalulekile. I-VCM ayincibiliki emanzini kuphela kodwa ixubana kakhulu nezinyibilikisi eziphilayo, okuthonya ukukhetha ezintweni zokuvimba kanye nezinyathelo zokunciphisa eziphuthumayo ngesikhathi sokuphathwa nokugcinwa.
Ukuphepha kanye Nokulawulwa Kwemvelo
I-vinyl chloride iwuketshezi oluvutha kakhulu kanye nomhwamuko, ene-flashpoint ephansi njenge--78°C kanye nobubanzi obubanzi bokuqhuma. Ubuthi bayo obukhulu kanye nokuba yingozi komdlavuza okuqashelwayo kudinga izinyathelo zokuphepha eziqinile ze-vinyl chloride monomer. Ekwakhiweni kwenqubo, amapayipi anezindonga ezimbili, i-nitrogen blanketing, kanye namanethiwekhi amaningi okuthola ukuvuza kusetshenziswa kuyo yonke inqubo yokukhiqiza i-vinyl chloride monomer.
Ukuthutha nokugcina kusebenzisa imikhumbi elinganiswe ngomfutho ehlonyiswe ngezinhlelo zokusiza kanye nezindawo ezifrijiwe ukuze kuncishiswe umfutho womusi ngaleyo ndlela kukhishwe ingozi. Izinqubo zokuqapha ukukhishwa komoya ngesikhathi sangempela kanye nokulawula zisebenza kokubili ukuphepha kwendawo yokusebenza kanye nokuthobela imvelo. Emifudlaneni evulekile, izinhlelo zokuhlanza kanye nezindawo zokushisa zinciphisa ukukhishwa kwama-hydrocarbon ane-chlorine, zinamathela ezindinganisweni zomthetho ezishintshayo emisebenzini yamakhemikhali ezimbonini. Ukuhlela okuphuthumayo kanye nokuzivocavoca okuvamile kusalokhu kuyimikhuba ephoqelekile kuzo zonke izitshalo zesimanje ze-VCM, ngenxa yokuthi kungenzeka ukuthi kube nezingozi zokuchayeka eziphuthumayo nezingapheli ezihlobene nale nhlanganisela.
Ukuthuthukiswa Kwenqubo Nokusebenza Kahle
Ukuthuthukiswa Kwamandla Nokuhlanganiswa
Ukuhlanganiswa kokushisa sekuyindlela eyinhloko ekwakhiweni kwenqubo yokukhiqiza i-vinyl chloride monomer. Ukuhlaziywa kwe-pinch kuyindlela eyisisekelo yokumaka imifudlana yenqubo eshisayo nebandayo, kwembula iphuzu lokuncishana—inkinga yokushisa lapho ukubuyiselwa kokushisa kwandiswa khona. Esitshalweni esivamile se-vinyl chloride monomer, imifudlana emikhulu edinga ukupholisa, njenge-EDC pyrolysis effluent, ifaniswa nemifudlana edinga ukufudumala, njenge-reboilers ezinyathelweni zokuhlanza ze-VCM. Ama-composite curve aphumayo asiza ekunqumeni izidingo eziphansi kakhulu zokusetshenziswa kokushisa nokubanda, ukuqinisekisa ukuthi inqubo isebenza eduze kwemikhawulo yayo yokusebenza kahle kwe-thermodynamic.
Amanethiwekhi okushintshanisa ukushisa alungiselelwe (ama-HEN) abuyisa ukushisa kusuka emifudlaneni eshisayo ephumayo ukuze afudumale kusengaphambili ukudla okubandayo okungenayo. Lokhu kusetshenziswa kabusha kwamandla ngendlela ehlelekile kunciphisa izindleko zensiza yomusi kanye nokupholisa ngo-10–30% uma kusetshenziswa ngokuqinile, njengoba kuboniswe ezifundweni zezitshalo ze-VCM ezigcwele. Izinhlelo zokusebenza zokulungisa kabusha zivamile, zivumela imishini ekhona ngokungeza ama-exchange ahambisanayo noma ukulungisa kabusha ukugeleza ngaphandle kwesikhathi esibalulekile sokungasebenzi. Lokhu kusetshenziswa okuhleliwe, okuqinisekiswe nge-steady-state simulation, kuqinisekisa ukuthi ukonga amandla kuyabonakala ngenkathi kugcinwa izindleko zemali ziphakathi.
Ukuhlanganiswa okusekelwe ku-pinch kwenza okungaphezu kokunciphisa izindleko zokusebenza. Kuphinde kushintshe ukusebenza kwemvelo iyonke—ukushiswa kancane kukaphethiloli kusho ukukhishwa kwe-CO₂ okuphansi, okusekela ukuhambisana nemithethonqubo yokuqinisa ukukhishwa kwegesi. Ukonga ukukhishwa kwegesi kuvame ukulingana namandla agciniwe; izitshalo zibika ukwehla kwe-CO₂ okungama-25% esigabeni se-VCM kuphela ngemuva kokuhlaziywa kwe-HEN okuqinisekiswe ukuhlaziywa kwejika elihlanganisiwe.
Amasu Okuthuthukisa Inqubo Ethuthukisiwe
Ukulingisa inqubo kusekela ukwenziwa ngcono kokugeleza kwenqubo yokukhiqiza i-vinyl chloride monomer. Besebenzisa ukulingisa okuzinzile, onjiniyela baklama futhi balinganise amayunithi amasha, bahlole izimo eziningi zokusebenza, futhi baqinisekise ukuthi izilinganiso zamandla nezinto ezibonakalayo ziqinile. Lokhu kuqinisekisa ukusebenza okuqinile kuzo zonke izinhlobo zenqubo kanye namazinga okukhiqiza alindelekile.
Ukwenza ngcono okunezinhloso eziningi, kusetshenziswa izindlela ezifana nama-algorithms ezakhi zofuzo, kulinganisela izinto eziza kuqala ezincintisanayo. Emisebenzini ye-VCM, izinhloso eziyinhloko ukukhiqizwa komkhiqizo, ukusetshenziswa kwamandla amancane, kanye nokunciphisa ukukhishwa kwamagesi okushisa okushisa. Izindlela zesimanje zihlanganisa uhlelo lwezibalo nolwazi lwenqubo ye-heuristic ukuze kukhiqizwe izakhiwo zezitshalo ezingokoqobo neziguquguqukayo. Lezi zindlela zivame ukuletha izixazululo ngokubuyiselwa kokushisa okuthuthukisiwe ngenkathi kugcinwa amazinga okukhipha kanye nokuhlanzeka komkhiqizo abalulekile ezinyathelweni zenqubo ye-PVC polymerization ezansi.
Ukulungiswa okuphindaphindiwe kubalulekile. Ngemva kokukhethwa kokucushwa kokuqala kwe-HEN ngokulingisa, ukuhlaziywa kwedatha yesitshalo kanye nokuqapha kwedijithali kunikeza ukuhlolwa kokusebenza kwesikhathi sangempela. Abaqhubi bangenza izinguquko ezincane—njengokulungisa amazinga okugeleza kwenqubo noma ukwabiwa kwemisebenzi yokushintshanisa ukushisa—ngokusekelwe kudatha yokushisa yangempela kanye nokwakheka. Le mpendulo iqinisekisa ukusebenza okuqhubekayo eduze kwamaphuzu okusetha umklamo olungiselelwe ngisho nalapho isidingo sokudla noma sokukhiqiza sishintsha.
Amathuluzi afana namamitha okuqina angaphakathi kanye namamitha okuqina avela eLonnmeter ahlinzeka ngokulinganisa okuqondile kwezakhiwo zoketshezi ngesikhathi sangempela. Lezi zilinganiso zikhomba ukuphambuka okungase kuvele ngenxa yokungcola, ukuphazamiseka kwenqubo, noma izinto zokuphakelayo ezingacacisiwe. Ngedatha enembile, yokuqina kwesikhathi sangempela kanye ne-viscosity, opharetha bagcina imigomo yokusebenza ebekwe ngesikhathi sokuklama kanye nezigaba zokuqalisa.
Ukuhlolwa Komnotho kanye Nezilinganiso Zokuzinza
Ukuhlolwa okuphelele kwezomnotho kwesitshalo se-VCM kulinganisa ukutshalwa kwezimali, izindleko zokusebenza, kanye nesikhathi sokukhokha. Izindleko zokuqala zemali zifaka phakathi izindleko zabashintshisi abasha, amapayipi, kanye nezinhlelo zokujikeleza kabusha ezidingekayo ukuze kuqaliswe noma kufakwe kabusha inethiwekhi yokushintshanisa ukushisa. Ngokulungisa kabusha, izindleko zemali ezengeziwe zihlala ziphansi ngoba imishini emikhulu yenqubo isetshenziswa kabusha noma isetshenziswe kabusha. Ukonga izindleko zokusebenza—ikakhulukazi amandla—kuvame ukunciphisa ukutshalwa kwezimali kungakapheli iminyaka eyi-1-3, ikakhulukazi ezindaweni ezinentengo ephezulu yegesi yemvelo noma umusi.
Izilinganiso zokuzinza enqubweni yokukhiqizwa kwe-vinyl chloride monomer zihlanganisa okungaphezu kokusetshenziswa kwamandla. Izinyathelo ezibalulekile zifaka phakathi ukusebenza kahle kwezinsizakusebenza, ukukhishwa kwe-CO₂ ngethani lomkhiqizo, kanye nokusetshenziswa kwamanzi kumasekethe okupholisa. Ukuhlaziywa kwezifundo zakamuva kuqinisekisa ukuthi ukwenziwa ngcono kwe-HEN njalo kuqhuba ukuthuthuka kulezi zilinganiso. Ukufakwa kwezinsizakusebenza okuphelele ngethani le-VCM kwehla, ukwehla kokukhishwa, kanye nokuhambisana nezinhlaka zokubika ukuzinza kuyathuthuka.
Izimo zokukhokha zivame ukuba nomthelela ekongeni okuqondile kwezinsizakusebenza kanye nezinzuzo ezingaqondile njengezikweletu zentela yekhabhoni ephansi kanye nezindleko ezimbalwa zemvume yokukhishwa komoya. Ezifundeni ezinengcindezi yokulawula ekhulayo, ikhono lesitshalo se-vinyl chloride monomer lokubonisa intuthuko eqhubekayo kulezi zilinganiso lithonya kakhulu ukusebenza kwesikhathi eside kanye nokuncintisana.
Ngamafuphi, ukwenza ngcono izinqubo kanye nokuhlanganiswa kwamandla—okusekelwe ekulingiseni okuthuthukisiwe, ukwenza ngcono okunezinhloso eziningi, kanye nokulinganisa okuqondile (njengalokho okuvunyelwe ubuchwepheshe beLonnmeter)—kwakha umongo womklamo wesitshalo se-vinyl chloride monomer sesimanje, esisebenzayo, nesiqhubekayo.
I-Polyvinyl Chloride (PVC) Polymerization Esebenzisa i-VCM
Isingeniso senqubo ye-PVC Polymerization
I-vinyl chloride monomer (VCM) iyisakhiwo esibalulekile sokukhiqizwa kwe-polyvinyl chloride (PVC). Ukusabela kwe-vinyl chloride polymerization kuguqula lolu ketshezi oluguquguqukayo, olungenambala lube olunye lwepulasitiki ezisetshenziswa kakhulu emhlabeni. I-PVC polymerization yenziwa kakhulu kusetshenziswa izindlela zokumiswa kanye ne-emulsion.
Ku-inqubo yokwenza i-polymerization yokumiswa, i-VCM ihlakazeka emanzini ngosizo lwezinto ezilengayo ezifana ne-polyvinyl alcohol noma i-methyl cellulose. Inqubo iqala ngokushukuma okuphezulu ukuze kukhiqizwe amaconsi amancane e-VCM amiswe esigabeni samanzi. Iziqalisi ze-polymerization, ngokuvamile ama-peroxide e-organic noma ama-azo compounds, zibe sezifakwa. Ngaphansi kwamazinga okushisa alawulwa kahle (ngokuvamile angu-40-70°C), amaconsi e-VCM ayenza i-polymer, akha ubuhlalu noma izinhlayiya ze-PVC. Iqoqo libanjwa ngaphansi kokushukuma, futhi izinga lokusabela linqunywa uhlobo lomqalisi, ukuhlushwa, kanye nephrofayili yokushisa. Ukulungiswa ngokucophelela kwalezi zinhlaka kubalulekile ukuqinisekisa ukusatshalaliswa kosayizi wezinhlayiya omncane nofanayo. Lapho sekuqediwe, ingxube yokusabela iyapholiswa, i-VCM engaphendulwanga iyasuswa, futhi izinto eziqinisayo noma iziguquli zingafakwa ngaphambi kwezigaba ezilandelayo zokuhlunga, ukugeza, nokomisa.
Iindlela yokwenza i-emulsion polymerizationisebenza ngesethi ehlukile yezidingo. Lapha, i-VCM ixutshwa emanzini kusetshenziswa ama-surfactants (ama-molecule afana nensipho), akha osayizi abancane kakhulu bamaconsi uma kuqhathaniswa nenqubo yokumiswa. Le ndlela ikhiqiza i-PVC latex—i-colloidal dispersion efanelekile kwizicelo ezikhethekile, njengezimbozo noma izikhumba zokwenziwa. Izinhlelo zokuqala zivame ukuthembela kuma-redox pairs, asebenza emazingeni okushisa aphansi kakhulu. I-Emulsion polymerization ivumela ukulawulwa okuhle kakhulu kwezici zezinhlayiya, njenge-morphology kanye ne-porosity, yize ihilela izinyathelo zokubuyisa umkhiqizo eziyinkimbinkimbi kakhulu.
Ubuchwepheshe besimanje be-PVC polymerization buvame ukuhlanganisa amathuluzi okuqapha asendaweni, njengezihlaziyi zosayizi wezinhlayiya noma amamitha obuningi obusemugqeni (njengoba akhiqizwe yi-Lonnmeter), enkambisweni. Lawa mathuluzi anikeza impendulo yesikhathi sangempela, okuvumela ukulungiswa okuqhubekayo kwesivinini sokushukuma, izinga lokushisa, kanye nokudla kokuqala, ngaleyo ndlela kuthuthukisa ukuhambisana komkhiqizo futhi kuncishiswe imfucuza.
Amapharamitha Ekhwalithi ye-VCM Okukhiqiza i-PVC Okuphumelelayo
Ukusebenza kahle kanye nekhwalithi yokukhiqizwa kwe-PVC kuhlobene kakhulu nezakhiwo zomzimba nezamakhemikhali ze-VCM. I-VCM ehlanzekile kakhulu ibalulekile ekupholimeni okuphumelelayo kanye nokusebenza kahle kwe-polymer okuphansi.
Ukungcola okukhona ku-VCM—njengamanzi asele, i-acetylene, izinto eziphilayo ezi-chlorine, noma ama-ion ensimbi—kungafaka ubuthi kubaqalisi, kubambezele amazinga okwenziwa kwe-polymerization, futhi kungenise amaphutha ku-resin ye-PVC. Isibonelo, ukuba khona kwama-hydrocarbon a-chlorine a-trace, ngisho nasezingxeni zezingxenye ngesigidi, kungashintsha i-kinetics yokusabela noma kuholele kumkhiqizo ongekho umbala. Izinqubo ezisebenzayo zokuhlanza i-vinyl chloride monomer ziyasetshenziswa phezulu, kusetshenziswa amasu anjengokucwiliswa kwezigaba eziningi (okusebenza emibhoshongweni yokucwiliswa ye-VCM ezinikele) ukunciphisa ukungcola kube yimingcele eyamukelekayo.
Izakhiwo zomzimba—ikakhulukazi ubuningi be-VCM kanye nokulawula kwayo—zidlala indima eqondile ekuphatheni nasekuphindaphindeni kwenqubo ezansi. Ubuningi boketshezi be-VCM buyahlukahluka kakhulu ngokushisa, okuthinta ukunemba kokulinganisa, ukuziphatha kwesigaba ngesikhathi se-polymerization, kanye nokusebenza kahle kokunyakaza. Isibonelo, ku-0°C, ubuningi be-VCM bungaba ngu-1.140 g/cm³, buyehla ngokwanda kokushisa. Ukuqapha okuthembekile, kwesikhathi sangempela kobuningi boketshezi be-VCM (kusetshenziswa amamitha obuningi angaphakathi njengalawo avela eLonnmeter) kuqinisekisa izilinganiso zokudla ezifanele, kwenza kube lula ukubalwa kokudlulisa ukushisa okunembile, futhi kusekela ukufana okuqinile komkhiqizo we-batch-to-batch.
Izinto ezingcolisayo ezisele, ikakhulukazi i-VCM engaphenduliwe, zingalimaza kokubili ukuphepha kanye nekhwalithi yomkhiqizo. Amazinga aphezulu e-VCM yamahhala ku-PVC eqediwe aletha izingozi ezinobuthi futhi angathinta kabi izakhiwo ezifana nokubhoboka, amandla omshini, kanye nokuqina kombala. Imithethonqubo ivame ukuphoqelela izinyathelo eziphelele zokususa kanye nokuqapha okuqhubekayo kwe-VCM kulo lonke umjikelezo wokukhiqiza ukuqinisekisa umkhiqizo ophephile nohambisanayo.
Umthelela wekhwalithi ye-VCM ku-PVC ufingqwe kahle kakhulu eshadini elilandelayo:
| Isibaluli Sekhwalithi ye-VCM | Umphumela enqubweni naseMkhiqizweni we-PVC |
| Ubumsulwa (ukwakheka kwamakhemikhali) | Kuthinta ngqo izinga le-polymerization, ukusatshalaliswa kwesisindo sama-molecule, umbala, kanye nokuqina kokushisa |
| Isimo somzimba (ukuminyana koketshezi) | Ithonya ukunemba kokulinganisa, ukusebenza kahle kokuxuba, kanye nesimo se-polymer |
| Okuqukethwe kokungcola | Kuholela ekucinyweni kwe-initiator, ekuvinjelweni kokusabela, kanye nezakhiwo ezimbi zemishini/zokusetshenziswa kokugcina |
| Izinsalela (isib. amanzi, izinto eziphilayo) | Kungabangela ukukhubazeka kwe-porosity, i-evenly particle morphology, kanye nezinkinga zokucubungula ezingezansi |
Ukuqinisekisa ukulawulwa okuqinile kwekhwalithi ye-VCM ngokuhlanzwa okuthuthukisiwe, isitoreji esifanele, kanye nobuchwepheshe bokulinganisa ubuningi besikhathi sangempela kubalulekile ekwakhiweni kwesitshalo se-vinyl chloride monomer okuphumelelayo kanye nokuhlangabezana nezinyathelo zokuphepha ezidingekayo kubuchwepheshe besimanje benqubo ye-vinyl chloride monomer.
imibuzo ejwayelekile ukubuzwa
Iyini inqubo ye-vinyl chloride monomer?
Inqubo yokukhiqizwa kwe-vinyl chloride monomer iwuchungechunge lwezimboni oluguqula i-ethylene ibe yi-vinyl chloride monomer (VCM), okuwukudla okubalulekile kokukhiqizwa kwe-resin ye-PVC. Iqala ngokufaka i-chlorine ye-ethylene, yakha i-ethylene dichloride (EDC), ngokuvamile ngokusebenzisa i-chlorine eqondile noma i-oxychlorination. Okulandelayo, i-EDC ehlanzekile kakhulu iqhekeka ngokushisa ezithandweni ku-480–520°C, ikhipha i-VCM kanye ne-hydrogen chloride (HCl). Ngaphansi komfula, imibhoshongo eminingi yokuhlanza ihlanza i-VCM, isusa ukungcola namanzi ukuze inikeze ubumsulwa obungaphezulu kuka-99.9% obubalulekile ekufakweni kwe-polymer. Ubunzima kanye nokucushwa komdwebo wokugeleza kokukhiqizwa kwe-vinyl chloride monomer kuncike ekwakhiweni kwezitshalo, imigomo yokusebenza kahle, kanye nokuhlanganiswa kwemfucuza.
Isitshalo se-vinyl chloride monomer siqinisekisa kanjani ukuphepha kanye nokuthobela imithetho yemvelo?
Ngenxa yokuthi i-VCM iyasha, ibangela umdlavuza, futhi iyingozi emvelweni, ukwakheka kwesitshalo se-vinyl chloride monomer kubeka phambili ukugcinwa nokunciphisa. Izikhungo zisebenzisa izixazululo zokulawula ukukhishwa kwegesi ezinezingqimba eziningi ukuze kuvinjwe umusi we-organochlorine. Izinhlelo zokuthola ukuvuza ezizenzakalelayo kanye nezinqubo zokuvala izinqubo zivimbela ukukhishwa ngengozi. Izindawo ezibucayi zisebenzisa izivalo ezivala igesi kanye namayunithi okunciphisa umoya. Umkhiqizo we-HCl uphinda usetshenziswe noma welashwe ukuze kuncishiswe ukungcola. Ukucima ngemva kokuqhekeka kwe-EDC kumisa ukwakheka kwe-dioxin. Ukuthobela imithetho kuqinisekiswa ngokuqapha okuhlanganisiwe kwesikhathi sangempela kanye nokunamathela emikhawulweni yokulawula ekukhishweni komoya namanzi.
Iyini i-vinyl chloride ewuketshezi, futhi kungani ubuningi bayo bubalulekile?
I-vinyl chloride ewuketshezi iwuhlobo olufingqiwe, olucindezelwe lwe-VCM—olugcinwa futhi luthuthwe ekushiseni okuphansi noma ekucindezelweni okuphezulu ukuvimbela ukuhwamuka. Ubuningi be-vinyl chloride ewuketshezi, ngokuvamile kusukela ku-0.910 kuya ku-0.970 g/cm³ kuye ngokushisa nokucindezela, kuyipharamitha ebalulekile yokuklama imikhumbi yokugcina izinto, amathangi omgwaqo, kanye nemigqa yokudlulisa. Idatha yobuningi be-VCM ibalulekile futhi ekulandeleni impahla, imisebenzi yokuxuba, izilinganiso ezinembile zesisindo, kanye nokuqinisekisa isivuno senqubo kulo lonke umsebenzi wokukhiqiza. Amamitha obuningi angaphakathi, njengalawo akhiqizwa yi-Lonnmeter, anikeza ukuqapha okuqhubekayo okudingekayo ukuze kuphephe ukusebenza kanye nokusebenza kahle.
Kungani umbhoshongo wokuhluza ubalulekile enqubweni yokuhlanzwa kwe-VCM?
Imibhoshongo yokucwilisa ibalulekile enqubweni yokuhlanzwa kwe-vinyl chloride monomer. Ihlukanisa i-VCM ne-EDC esele, ukungcola okune-chlorine okubilayo kancane, kanye "neziphetho ezinzima" ezakheka ngesikhathi sokukhiqizwa. Ukusebenza kahle kombhoshongo wokucwilisa we-VCM kuqinisekisa ukuthi i-monomer yokuphakelayo nge-polymerization ihlangabezana nezindinganiso zekhwalithi eziqinile. Noma yikuphi ukungcola, njengezakhi ezingagcwalisiwe noma umswakama, kungaphazamisa izinyathelo zenqubo ye-PVC polymerization, kubangele i-resin engacacisiwe, noma kulimaze ama-catalyst angaphansi komfula. Amasu athuthukile okuhlanza i-VCM asebenzisa ama-rectifiers anemiphumela eminingi kanye nama-tray akhethekile ukuze kuthuthukiswe ukuhlukaniswa, kubuyiselwe imikhiqizo ephumayo, futhi kuncishiswe ukungcola kwe-reboiler.
Inqubo yokwenza i-PVC polymerization ihlobene kanjani nokukhiqizwa kwe-vinyl chloride monomer?
Ubumsulwa nokuqina kwe-VCM kuyizinto ezidingekayo ukuze kube nama-resin e-polyvinyl chloride asezingeni eliphezulu. Inqubo yokwenza i-PVC polymerization isebenzisa ngqo i-VCM kuma-reactor e-polymerization (ngokuvamile ngokumiswa, i-emulsion, noma ubuchwepheshe obukhulu). Ukulawulwa okunembile kokwakheka kwe-VCM kuthinta isakhiwo sama-molecule, amaphrofayili okungcola, kanye nezakhiwo zomzimba zemikhiqizo yokugcina ye-PVC. Ukuxhumana okuseduze phakathi kwenqubo yokukhiqiza i-vinyl chloride monomer kanye nobuchwepheshe be-PVC polymerization kusho ukuthi noma yikuphi ukushintshashintsha kwenqubo ku-VCM—njengokwehluka kobuningi, ukungcola okulandelwayo, noma ukuvakasha kwezinga lokushisa—kungasakazeka kuze kube sezingeni lokwenza i-polymerization, kuthinte ukusebenza kahle kanye nokusebenza komkhiqizo.
Isikhathi sokuthunyelwe: Disemba 18-2025
