Qhov sib txawv tseem ceeb ntawm kraft thiab sulfite pulping yog kraft pulping cuam tshuam nrog kev kho cov ntoo chips nrog kub sib tov ntawm dej, sodium hydroxide thiab sodium sulfide whereas sulfite pulping cuam tshuam nrog kev kho cov ntoo chips nrog sulfite los yog bisulfite ntsev. sodium, calcium, potassium, magnesium lossis ammonium.
Ntoo pulp ntau lawm yog ib qho tseem ceeb heev hauv papermaking thiab lwm yam kev xav tau kev lag luam. Nyob rau hauv cov txheej txheem ntawm ntoo pulping, peb cais cellulose fibers los ntawm ntoo los yog chemically los yog mechanically. Qhov no siv tau los ua raw khoom rau kev tsim cov ntawv.
Kraft Pulping yog dab tsi?
Kraft pulping yog txheej txheem siv los hloov ntoo rau hauv cov ntaub ntoo siv cov dej sib tov, sodium hydroxide thiab sodium sulfide. Ntoo muaj yuav luag ntshiab cellulose fibers, uas yog lub ntsiab ntawm daim ntawv. Yog li ntawd, ntoo pulp yog ib qho tseem ceeb hauv kev tsim cov ntawv. Cov txheej txheem kraft yuav tsum muaj cov dej sib tov kub, NaOH, thiab Na2S (tseem hu ua cawv dawb) uas tuaj yeem rhuav tshem cov kev sib raug zoo ntawm lignin, hemicellulose, thiab cellulose. Qhov no yog txoj kev loj uas siv rau kev tsim cov ntoo pulp. Nws muaj ob qho tib si chemical thiab mechanical cov kauj ruam. Txawm li cas los xij, muaj qee qhov kev xav txog cov txheej txheem no vim tias nws tuaj yeem tso cov khoom tsw ntxhiab thiab qee zaum txawm tias cov kua khib nyiab.
Daim duab 01: Ntoo Chips
Muaj ntau cov kauj ruam hauv cov txheej txheem kraft pulping: impregnation, ua noj, rov qab, tshuab, tshuaj ntsuam, ntxuav, thiab tshuaj dawb. Cov kauj ruam impregnation yuav tsum ua ntej steaming ntawm ntoo chips qhov twg ntoo chips tau wetted thiab preheated nrog chav. Cov kauj ruam tom ntej yog ua noj nyob rau hauv uas ntoo chips yog siav nyob rau hauv pressurized hlab ntsha hu ua digesters. Cov kauj ruam tom ntej yog cov txheej txheem rov qab uas cov kua ntau dhau thiab cov khoom siv tau raug tshem tawm los ntawm kev siv ntau yam evaporator uas cov sib tov yog concentrated.
Kauj ruam plaub ntawm txheej txheem yog tshuab kauj ruam. Nyob rau hauv cov kauj ruam no, cov tiav lawm thiab siav chips yog tshuab mus rau hauv ib tug sau tank (lub tshuab nqus tsev tank), uas tso cai rau tso tawm ntau ntawm chav thiab volatiles. Ntawm no, cov volatiles yog condensed thiab sau. Cov kauj ruam tom ntej yog kev tshuaj ntsuam xyuas, nyob rau hauv uas lub pulp yog cais los ntawm loj shives, knots, av thiab seem ntawm cov khib nyiab. Tom qab ntawd los ntawm cov kauj ruam ntxuav qhov twg cov dej cawv sib cais los ntawm cov cellulose fibers nyob rau hauv ib tug series ntawm 3-5 ntxuav theem. Cov kauj ruam kawg ntawm cov txheej txheem no yog bleaching.
Sulphite Pulping yog dab tsi?
Sulfite pulping yog txheej txheem siv los tsim cov ntoo ntoo siv sulfites lossis bisulfite ntsev ntawm sodium, calcium, potassium, magnesium, thiab ammonium. Cov kev daws teeb meem ntawm cov sulfites los yog bisulfites yog siv los kho cov ntoo chips, uas ua rau lub cleavage ntawm tshuaj bonds ntawm cellulose thiab lignin. Thaum lub sijhawm txheej txheem no, lignin hloov mus rau hauv cov kua qaub lignosulfonates, thiab peb tuaj yeem yooj yim cais cov compound no los ntawm cellulose fibers. Tsis zoo li cov txheej txheem kraft, cov txheej txheem sulfite tsim cov fibers muaj zog, thiab cov txheej txheem no tsis muaj teeb meem rau ib puag ncig.
Daim duab 02: Cov Lus Teb Loj hauv Cov Txheej Txheem Sulfite
Thawj kauj ruam ntawm cov txheej txheem sulfite yog pulping cawv npaj. Rau feem ntau sulfite mills, cov dej cawv pulping yog lub hauv paus (hydroxides ntawm alkali hlau thiab alkaline ntiaj teb hlau) nrog sulfur dioxide. Txawm li cas los xij, peb tuaj yeem siv carbonated los ntawm hydroxide. Cov kauj ruam no tsim sulfites thiab bisulfites. Cov kauj ruam tom ntej yog kev zom zaub mov uas ua rau hauv cov hlab ntsha loj hu ua digesters. Ntawm no, cov ntoo chips raug kho nrog cov cawv pulping. Cov tshuaj tiv thaiv no ua rau lignosulfonates ua cov khoom lag luam uas muaj txiaj ntsig zoo hauv lwm daim ntawv thov. Cov kauj ruam kawg yog cov tshuaj rov qab siv cov tshuab ntxhua khaub ncaws, tshem tawm cov tshuaj siv ua noj thiab degraded lignin thiab hemicellulose.
Qhov txawv ntawm Kraft thiab Sulfite Pulping yog dab tsi?
Kraft thiab sulfite txheej txheem yog ob txoj hauv kev tsim cov ntoo ntoo los ntawm cov ntoo chips. Qhov sib txawv tseem ceeb ntawm cov txheej txheem kraft thiab sulfite pulping yog tias kraft pulping cuam tshuam nrog kev kho cov ntoo chips nrog cov dej kub sib tov, sodium hydroxide thiab sodium sulfide whereas sulfite pulping cuam tshuam nrog kev kho ntoo chips nrog sulfite lossis bisulfite ntsev ntawm sodium, calcium, poov tshuaj, magnesium los yog ammonium. Qhov tseem ceeb, sulfite pulping yog ib puag ncig zoo dua li kraft pulping.
Hauv qab infographic qhia ib sab ntawm kev sib piv ntawm qhov sib txawv ntawm kraft thiab sulfite pulping.
Summary – Kraft vs Sulfite Pulping
Ntoo pulp yog cov khoom siv tseem ceeb hauv kev lag luam xws li kev lag luam ntawv. Kraft pulping txheej txheem thiab cov txheej txheem sulfite yog siv rau kev tsim cov ntoo pulp los ntawm ntoo chips. Qhov sib txawv tseem ceeb ntawm kraft thiab sulfite pulping txheej txheem yog cov txheej txheem kraft pulping suav nrog kev kho cov ntoo chips nrog cov dej kub sib tov, sodium hydroxide thiab sodium sulfide whereas sulfite pulping txheej txheem suav nrog kev kho ntoo chips nrog sulfite lossis bisulfite ntsev ntawm sodium, calcium, potassium, magnesium los yog ammonium.
