Cov txheej txheem tsim cov yas PETE thiab nws daim ntawv thov hauv kev ntim dej haus
PETE (Polyethylene Terephthalate) yas, feem ntau sau ua PET, yog ib hom yas siv dav tshaj plaws hauv ntiaj teb, tshwj xeeb tshaj yog rau cov dej haus ntim xws li cov fwj dej ntxhia, dej qab zib, tshuaj yej npaj txhij haus, thiab kua txiv hmab txiv ntoo. PETE paub txog nws lub teeb, ntshiab, muaj zog, thiab muaj kev nyab xeeb rau kev sib cuag zaub mov thaum tsim raws li cov qauv. Tom qab lub raj mis PETE zoo li yooj yim, muaj ntau cov txheej txheem kev lag luam ntev heev: los ntawm kev tsim cov khoom siv raw, polymerization, resin pelletization, mus rau kev tsim lub raj mis. Tsab xov xwm no tham txog cov txheej txheem tsim yas PETE thiab nws siv li cas rau kev ntim dej haus zoo thiab nrov.
1. Paub txog PETE: cov qauv thiab cov yam ntxwv tseem ceeb
PETE yog ib hom thermoplastic polymer uas yog los ntawm tsev neeg polyester. Hauv kev tshuaj lom neeg, PET yog tsim los ntawm kev sib xyaw ntawm cov khoom uas muab ib pawg ethylene thiab ib qho khoom uas muab ib pawg terephthalate. Nws cov qauv polymer tsim cov khoom sib xyaw ua ke uas muaj txiaj ntsig zoo rau kev ntim khoom: pob tshab, tiv taus kev cuam tshuam nruab nrab, ruaj khov, thiab tiv thaiv cov pa roj thiab cov pa dej. Rau cov chaw tsim khoom haus, cov khoom thaiv no yog qhov tseem ceeb rau kev tswj cov khoom zoo, piv txwv li, tswj cov pa roj carbon hauv cov dej qab zib lossis pab qeeb oxidation uas tuaj yeem ua rau cov saj puas tsuaj.
Ntawm qhov tod tes, PET muaj qhov txwv: nws qhov kev tiv taus kub siab tsis zoo li qee cov yas lwm yam, ua rau nws tsis zoo rau cov ntawv thov uas xav tau kev tua kab mob kub siab, xws li cov ntim khoom rov qab. Txawm li cas los xij, rau cov dej haus txias lossis kub hauv chav, PET yog qhov kev xaiv pheej yig heev.
2. Cov khoom siv raw tseem ceeb: PTA/DMT thiab MEG
Hauv kev lag luam, PET feem ntau yog ua los ntawm ob yam khoom siv tseem ceeb:
1. PTA (Purified Terephthalic Acid) lossis lwm txoj hauv kev DMT (Dimethyl Terephthalate) ua qhov chaw ntawm cov pab pawg terephthalate.
2. MEG (Mono Ethylene Glycol) ua ib qho chaw ntawm cov pab pawg ethylene.
Tam sim no, txoj kev PTA + MEG tau siv dav dua vim yog kev ua haujlwm zoo thiab tus nqi. Ob qho tib si cov khoom siv raw yog los ntawm kev lag luam petrochemical, txawm hais tias cov kev xaiv bio-based rau qee cov khoom (xws li bio-MEG) tau nyuam qhuav muaj los txo cov pa roj carbon.
3. Cov theem tshuaj tiv thaiv: esterification / transesterification thiab polycondensation
Cov txheej txheem tsim khoom PETE hauv lub Hoobkas resin muaj ob theem tseem ceeb ntawm kev ua haujlwm.
a) Esterification (PTA txoj kev) lossis transesterification (DMT txoj kev)
– Thaum siv PTA, qhov kev tshuaj tiv thaiv esterification tshwm sim ntawm PTA thiab MEG. Qhov kev tshuaj tiv thaiv no tsim cov oligomers (cov saw hlau luv luv) thiab tsim cov dej ua cov khoom seem. Cov dej yuav tsum tau tshem tawm ntawm lub kaw lus kom qhov kev tshuaj tiv thaiv no nce mus rau kev tsim oligomer.
– Yog siv DMT, transesterification tshwm sim nrog MEG, tsim cov methanol ua cov khoom seem.
Nyob rau theem no, kev tswj qhov kub thiab txias, siab, thiab cov khoom siv raw yog qhov tseem ceeb heev kom ntseeg tau tias muaj kev tsim oligomer zoo thiab tsim cov khoom sib xyaw kom raug rau theem tom ntej.
b) Polycondensation (kev tsim cov saw polymer ntev)
Thaum cov oligomers tau tsim, cov txheej txheem txuas ntxiv nrog polycondensation kom nce qhov ntev ntawm cov saw hlau (qhov hnyav molecular) kom cov khoom siv kho tshuab thiab lub cev ua tau raws li cov qauv siv. Nyob rau theem no, cov khoom seem (feem ntau yog glycol ntau dhau) kuj tseem yuav tsum tau tshem tawm ntawm lub reactor. Cov lag luam feem ntau siv lub tshuab nqus tsev thiab qhov kub siab kom txhawb nqa cov tshuaj tiv thaiv los tsim cov polymers ntev dua.
Cov tshuaj catalysts feem ntau siv los ua kom cov tshuaj tiv thaiv sai dua thiab tswj cov tshuaj resin zoo. Txawm li cas los xij, kev xaiv cov tshuaj catalyst yuav tsum xav txog kev nyab xeeb ntawm cov zaub mov thiab qhov cuam tshuam rau cov xim / qhov meej ntawm cov khoom. Cov tshuaj PET rau cov fwj dej haus feem ntau xav tau qhov meej thiab cov khoom tsis muaj kuab paug.
4. Kev tsim cov roj hmab: txias, txiav, thiab ziab
Tom qab cov txheej txheem polymerization tiav lawm, cov PET yaj raug extruded los ntawm lub pwm thiab txiav ua cov granules me me hu ua pellets lossis chips. Theem no suav nrog:
- Extrusion: hloov cov kua PET mus rau hauv cov xov.
- Pelletizing: cov xov raug txiav ua cov pellets loj sib npaug.
- Kev txias thiab crystallization thaum pib: pab kom pellet ruaj khov.
– Kev ziab: Qhov no tseem ceeb heev vim tias PET yog hygroscopic (nyiam nqus cov dej noo). Cov dej noo ntau dhau tuaj yeem ua rau puas tsuaj thaum lub sijhawm ua lub raj mis thiab cuam tshuam rau lub zog thiab kev meej.
Rau cov ntawv thov fwj dej haus, qhov zoo ntawm cov resin feem ntau raug txhim kho los ntawm kev tswj nws "intrinsic viscosity" (IV), ib qho parameter ntsig txog qhov ntev ntawm cov saw polymer. Cov resin nrog IV tsim nyog yuav tsim lub raj mis uas muaj zog tab sis tsis hnyav.
5. Los ntawm cov resin mus rau preform: cov txheej txheem txhaj tshuaj molding
Cov kauj ruam tom ntej yog hloov cov PET pellets mus ua preforms, uas yog cov me me, tubular "lub raj mis sib tw" nrog lub caj dab thiab lub hau xov tiav. Preforms yog ua los ntawm kev txhaj tshuaj molding, ib qho txheej txheem uas PET pellets raug yaj thiab tom qab ntawd txhaj rau hauv pwm.
Vim li cas ho ua preform? Vim tias txoj hauv kev no muaj txiaj ntsig zoo: lub caj dab ntawm lub raj mis tuaj yeem ua tau raws li qhov xav tau (qhov tseem ceeb rau kev ruaj khov ntawm lub hau thiab tiv thaiv kev xau), thaum lub cev tom qab ntawd raug tsim los ntawm cov txheej txheem tshuab pwm.
Thaum lub sijhawm txhaj tshuaj molding, cov PET resin yuav tsum qhuav tag. Yog tias nws tseem muaj dej, PET tuaj yeem hydrolyze thaum yaj, ua rau cov saw polymer tawg thiab cov khoom ua brittle lossis opaque.
6. Lub raj mis ua: tshuab molding (ncab tshuab molding)
Tom qab ntawd, cov preform raug rov ua kom sov mus rau qhov kub thiab txias kom raug (saum toj no qhov kub hloov iav tab sis qis dua nws qhov melting point), thiab tom qab ntawd ua rau hauv lub raj mis siv cov tshuab ncab. Cov kauj ruam tseem ceeb:
1. Rov ua kom sov: qhov preform raug cua sov kom sib npaug.
2. Ncab: tus pas nrig rub (ncab pas nrig) rub lub preform ntev.
3. Tshuab: cua siab tshuab lub preform kom txog thaum nws lo rau ntawm phab ntsa ntawm lub pwm raj mis.
4. Txias: lub raj mis raug txias kom nws cov duab ruaj khov.
Cov txheej txheem "ncab" no txhim kho kev taw qhia ntawm cov molecule, ua rau lub raj mis muaj zog dua, tiv taus kev nyem sab hauv (tseem ceeb rau dej qab zib), thiab muaj cov khoom thaiv zoo dua li yog tias nws tsuas yog cua tsis ncab.
7. Kev siv PETE hauv kev ntim dej haus
PETE zoo heev rau kev ntim dej haus rau ntau qhov laj thawj tseem ceeb:
- Lub teeb thiab muaj zog: txo cov nqi thauj mus los thiab kev pheej hmoo ntawm kev tawg piv rau iav.
- Pob tshab thiab txaus nyiam: cov neeg siv khoom tuaj yeem pom cov ntsiab lus ntawm cov khoom.
- Sib xws nrog kev tsim khoom loj: kev kub ceev, tus nqi qis.
- Kev ua tau zoo rau kev ua pa roj carbon: Lub raj mis PET rau cov dej haus carbonated yog tsim los kom tiv taus qhov siab.
– Siv Tau Dua: PET yog ib hom yas uas muaj cov txheej txheem siv dua tshiab zoo tshaj plaws.
Cov ntawv thov PETE muaj xws li:
- Cov fwj dej ntxhia ntawm ntau qhov ntau thiab tsawg.
- Cov dej haus uas muaj pa roj carbon dioxide (nrog rau lub raj mis uas muaj qauv thiab tuab ib yam).
- Tshuaj yej, kas fes uas haus tau thiab dej haus uas muaj ntxhiab tsw qab.
– Kua txiv hmab txiv ntoo thiab dej haus isotonic (feem ntau xav tau kev tiv thaiv ntxiv los ntawm oxygen lossis lub teeb).
Rau cov khoom uas rhiab heev rau oxygen lossis UV, cov lag luam tuaj yeem ntxiv cov thev naus laus zis xws li cov txheej thaiv, cov khoom ntxiv uas thaiv oxygen, lossis cov xim hauv lub raj mis (piv txwv li, xim av) kom txo qhov zoo ntawm cov khoom.
8. Tej Yam Uas Yuav Tsum Tau Ua: kev nyab xeeb, qhov zoo, thiab ib puag ncig
Txawm hais tias PETE siv dav dav, tseem muaj cov teeb meem uas yuav tsum tau tswj hwm:
– Qhov zoo thiab kev nyab xeeb ntawm cov khoom noj: Cov chaw tsim khoom yuav tsum xyuas kom meej tias kev tsiv teb tsaws chaw ntawm cov tshuaj los ntawm cov ntim khoom mus rau cov dej haus yog nyob rau hauv cov kev cai lij choj. Kev huv ntawm cov resin thiab kev tswj cov txheej txheem yog qhov tseem ceeb.
– Kev tiv taus kub: Cov fwj PET txheem tsis haum rau qhov kub thiab txias heev. Rau cov dej haus kub, yuav tsum muaj qib PET tshwj xeeb thiab tsim lub raj mis uas tuaj yeem tiv taus qhov ntsws.
– Kev cuam tshuam rau ib puag ncig: Qhov teeb meem tseem ceeb tsis yog cov khoom siv nws tus kheej, tab sis yog kev tswj cov khib nyiab. PET muaj peev xwm rov ua dua tshiab tau zoo, tab sis xav tau kev sau thiab cais cov khoom zoo.
Kev siv rPET (PET rov ua dua tshiab) tau dhau los ua ib qho uas siv ntau dua rau cov fwj dej haus. Txawm li cas los xij, rPET rau kev sib cuag nrog zaub mov yuav tsum dhau los ntawm cov txheej txheem rov ua dua tshiab uas ua tau raws li cov qauv nruj kom ntseeg tau tias muaj kev nyab xeeb thiab kev sib xws.
Xaus
Cov txheej txheem ntawm kev ua PETE yas rau kev ntim dej haus muaj ntau kauj ruam, los ntawm cov tshuaj lom neeg mus rau kev tsim polymer (esterification / transesterification thiab polycondensation), mus rau kev tsim cov resin pellets, kev tsim cov preforms los ntawm kev txhaj tshuaj molding, thiab kev tsim cov fwj los ntawm kev ncab tshuab molding. PETE qhov zoo - lub teeb, muaj zog, meej, thiab rov ua dua tshiab - ua rau nws yog qhov kev xaiv tseem ceeb rau kev lag luam dej haus. Mus tom ntej, kev tsim kho tshiab hauv kev siv tshuab thaiv, kev tsim lub raj mis sib dua, thiab kev siv rPET yuav txiav txim siab ntau ntxiv txog kev ruaj khov ntawm PETE siv ua cov ntim dej haus zoo thiab zoo rau ib puag ncig.
Yog tias koj xav tau, kuv tuaj yeem ntxiv ib ntu tshwj xeeb rau cov txheej txheem rov ua dua tshiab ntawm PET rau rPET, lossis piav qhia qhov sib txawv ntawm PET kub thiab CSD (dej qab zib carbonated) PET nrog rau cov piv txwv ntawm cov qauv raj mis.
