Polypropylene Txheej Txheem

Polypropylene resin yog ib qho ntawm plaub lub hom phiaj thermoplastic resins (polyethylene, polyvinyl chloride, polypropylene, polystyrene). Nws yog tsim los ntawm polymerization cov tshuaj tiv thaiv nrog propylene li raw khoom thiab ethylene li comonomer.
Cov txheej txheem txheej txheem siv los tsim polypropylene nyob rau hauv lub ntiaj teb no feem ntau poob rau hauv cov nram qab no pawg raws li pawg: hnyav txoj kev, txoj kev tov, kua theem bulk method (xws li kua theem roj theem ua ke hom) thiab roj theem bulk method. Cov yam ntxwv ntawm txhua tus txheej txheem tau piav qhia luv luv raws li hauv qab no:
kuab tshuaj polymerization
Txoj kev hnyav (tseem hu ua slurry method lossis av nkos txoj kev, slurry method) yog cov txheej txheem ua ntej tshaj plaws ntawm polypropylene. Txawm li cas los xij, vim cov txheej txheem deashing thiab hnyav rov qab, cov txheej txheem yog ntev thiab nyuaj, thiab nrog rau kev nce qib ntawm catalyst kev tshawb fawb thev naus laus zis, txij li xyoo 1980s, cov txheej txheem hnyav tau ua rau stagnate thiab tau maj mam hloov los ntawm cov txheej txheem kua theem ntau.
Cov txheej txheem nta: (1) Propylene monomer yog yaj nyob rau hauv ib qho inert kua hnyav (xws li hexane), thiab hnyav polymerization yog ua raws li qhov kev txiav txim ntawm catalyst. Lub polymer raug tshem tawm nyob rau hauv cov kuab tshuaj nyob rau hauv daim ntawv ntawm cov khoom hais, thiab ib tug kettle-hom stirring reactor yog siv; (2) Muaj cov txheej txheem deashing thiab hnyav rov qab. Cov txheej txheem yog ntev thiab nyuaj, nrog rau cov cuab yeej loj peev thiab kev siv zog siab. Txawm li cas los xij, kev tsim khoom yog yooj yim los tswj thiab cov khoom zoo yog qhov zoo; (3) Cov khoom siv polypropylene tau sib cais los ntawm centrifugal filtration thiab ces qhuav los ntawm huab cua ntws boiling thiab extrusion granulation.
kev daws teeb meem polymerization
Cov yam ntxwv ntawm tus txheej txheem: (1) Siv high-boiling point linear hydrocarbons ua cov kuab tshuaj thiab ua haujlwm ntawm qhov kub siab tshaj qhov melting point ntawm polypropylene. Lub resulting polymers yog tag nrho yaj nyob rau hauv cov kuab tshuaj thiab uniformly faib; (2) High-temperature gas stripping method evaporates thiab tshem tawm cov kuab tshuaj. Molten polypropylene tau txais, thiab tom qab ntawd extruded thiab granulated kom tau cov khoom pellet; (3) Tsuas yog cov chaw tsim khoom yog American Kodak Company.
Liquid Phase bulk method
Cov theem ua kua thiab roj theem sib xyaw ua ke, cov txheej txheem ua kua theem ntau cov txheej txheem polypropylene yog txheej txheem tshiab tsim nyob rau hauv nruab nrab thiab lig theem ntawm polypropylene ntau lawm. Cov txheej txheem tsim khoom no tau tsim tawm xya xyoo tom qab polypropylene pib muaj kev lag luam hauv xyoo 1957.
Txoj kev ua kua theem ntau yog siv los tsim polypropylene. Lub catalyst yog ncaj qha dispersed nyob rau hauv cov kua theem propylene yam tsis tau ntxiv lwm yam hnyav rau cov tshuaj tiv thaiv system ua cov kua theem bulk polymerization ntawm propylene. Cov polymer tsis tu ncua los ntawm cov kua propylene thiab raug tshem tawm hauv cov kua propylene hauv daim ntawv ntawm cov khoom zoo. Raws li lub sij hawm cov tshuaj tiv thaiv nce, qhov concentration ntawm polymer hais nyob rau hauv cov kua propylene nce. Thaum cov propylene hloov dua siab tshiab nce mus txog ib theem, cov unpolymerized propylene monomer rov qab los ntawm flash evaporation kom tau ib tug hmoov polypropylene khoom. Qhov no yog ib qho yooj yim thiab siab heev industrial ntau lawm txoj kev ntawm polypropylene. Cov txheej txheem ua kua theem sawv cev rau cov thev naus laus zis tshiab thiab qib tshiab ntawm polypropylene ntau lawm hauv ntiaj teb hauv xyoo 1980s.
Cov txheej txheem nta: (1) Tsis muaj cov kuab tshuaj ntxiv rau hauv lub cev, propylene monomer tau dhau los ua cov theem ua kua polymerization nyob rau hauv lub hwj reactor nyob rau hauv lub xeev ua kua, thiab ethylene propylene undergoes roj theem copolymerization nyob rau hauv ib tug fluidized txaj reactor; (2) Cov txheej txheem yooj yim, Cov khoom siv tsawg dua, kev nqis peev tsawg, kev siv hluav taws xob tsawg thiab cov nqi tsim khoom; (3) Homopolymerization txais yuav lub hwj chim stirred reactor (Hypol txheej txheem) los yog voj reactor (Spheripol txheej txheem), random copolymerization thiab thaiv copolymerization yog ob qho tib si nyob rau hauv stirred hom ua nyob rau hauv ib tug fluidized txaj.
Ib tug neeg sawv cev ntawm cov kua theem ntau txoj kev yog BASELL's Spherizone kua theem txheej txheem txheej txheem. Spherizone yog lub tshuab hluav taws xob siv hluav taws xob siv hluav taws xob siv Ziegler-Natta catalyst uas tsim cov polymers uas tswj cov tawv nqaij thiab kev ua tau zoo thaum ua cov crystalline heev, tawv thiab ntau yam. Nws ua tau zoo ib yam multimonomer resins lossis bimodal homopolymers hauv ib lub reactor. Lub voj voog Spherizone cov tshuaj tiv thaiv muaj ob thaj chaw sib cuam tshuam. Cov chaw sib txawv ua lub luag haujlwm ntawm cov pa roj theem thiab cov kua theem voj reactors ntawm lwm cov txheej txheem. Ob lub cheeb tsam no tuaj yeem tsim cov resins nrog qhov sib txawv ntawm qhov sib txawv ntawm cov khoom sib txawv lossis cov monomer muaj pes tsawg leeg faib, nthuav dav kev ua haujlwm ntawm polypropylene.
Cov cuab yeej tseem ceeb ntawm cov txheej txheem no yog MZCR (multi-zone circulation reactor system) reactor R230 system. Lub reactor muaj ib tug riser thiab downcomer. Nyob rau hauv lub riser, lub polymer yog cua tshuab upwards los ntawm cov tshuaj tiv thaiv roj los tsim fluidization, thiab xa mus rau sab sauv ntawm downcomer thiab dhau los ntawm lub cyclone separator. Cov hmoov yog sau nyob rau hauv lub downcomer. Cov roj cov tshuaj tiv thaiv yog circulated los ntawm ib tug centrifugal compressor los ntawm ib tug sab nraud pipeline, thiab cov tshuaj tiv thaiv tshav kub yog muab tshem tawm los ntawm ib tug circulator cooler nyob rau hauv lub sab nraud ncig pipeline. Cov khoom lag luam reactor raug tso tawm los ntawm lub valve ntsia hauv qhov qis ntawm tus downcomer. Tom qab cov hmoov tso tawm yog degassed nyob rau hauv siab siab thiab tsis tshua muaj siab, nws yog ncaj qha steamed thiab qhuav thaum tsim homopolymers thiab random copolymer kom tau cov hmoov khoom. Thaum tsim cov khoom siv los tiv thaiv kev cuam tshuam, cov hmoov tom qab kev kub siab degassing yog tawm mus rau hauv cov pa roj-theem fluidized txaj reactor. Lub reactor tseem siv Spheripol II roj theem reactor system. Lub copolymerization reactor yog lub nkoj ntsug cylindrical nrog lub taub hau kheej kheej nyob rau sab sauv thiab sab qis thiab lub txaj ebullating nyob rau sab qis. Cov khoom tseem ceeb yog stainless hlau thiab sab hauv yog polished.
Tam sim no lub peev xwm ntau lawm ntawm cov txheej txheem no hauv ib kab tau mus txog 450,{1}} tons / xyoo. Cov ntsiab lus ethylene ntawm MZCR (multi-zone circulation reactor) cuam tshuam cov khoom copolymer tuaj yeem siab txog 22% (cov ntsiab lus roj hmab ntau dua 40%), thiab cov khoom siv terpolymer uas muaj ethylene thiab 1-butene kuj tuaj yeem tsim.