Kupanga mapepala a nsungwi ku China kwakhala ndi mbiri yakale. Kapangidwe ka ulusi wa nsungwi ndi mankhwala ake ali ndi makhalidwe apadera. Utali wa ulusi wapakati ndi wautali, ndipo kapangidwe kake ka khoma la cell ya ulusi ndi kapadera, komwe kumakhudza mphamvu ya chitukuko cha pulp ndikwabwino, zomwe zimapangitsa kuti pulp yophwanyika ikhale ndi mawonekedwe abwino: kutseguka kwambiri komanso kufalikira kwa kuwala. Kuchuluka kwa zinthu zopangira nsungwi (pafupifupi 23% mpaka 32%) ndikokwera, zomwe zimapangitsa kuti pulp yake iphike ndi alkali ndi sulfide yambiri (sulfide nthawi zambiri 20% mpaka 25%), pafupi ndi matabwa a coniferous; zinthu zopangira, hemicellulose ndi silicon ndizokwera, komanso kutsuka kwa pulp, kusamba kwa zakumwa zakuda ndi kusungunuka kwa zida zamagetsi. Kugwira ntchito kwabwino kwabweretsa zovuta zina. Komabe, zinthu zopangira nsungwi sizinthu zabwino zopangira mapepala.
Njira yoyeretsera nsungwi yapakatikati komanso yayikulu ya mankhwala a pulp mill, makamaka idzagwiritsa ntchito njira yoyeretsera ya TCF kapena ECF. Kawirikawiri, kuphatikiza kuzama kwa delignification ndi oxygen deignification ya pulping, kugwiritsa ntchito ukadaulo wa TCF kapena ECF bleaching, malinga ndi kuchuluka kwa magawo osiyanasiyana a bleaching, pulp ya nsungwi imatha kuyera mpaka 88% ~ 90% ISO whiteness.
Kuyerekeza kwa ECF ya bamboo ndi TCF bleaching
Chifukwa cha kuchuluka kwa lignin mu nsungwi, iyenera kuphatikizidwa ndi ukadaulo wozama wa delignification ndi oxygen deignification kuti ilamulire kuchuluka kwa Kappa kwa slurry yolowera ku ECF ndi TCF (yolimbikitsidwa <10), pogwiritsa ntchito Eop enhanced two-stage ECF bleaching sequence, acid pretreatment kapena Eop two-stage TCF bleaching sequence, zonse zomwe zimatha kuyeretsa sulphate ya nsungwi mpaka kufika pamlingo woyera kwambiri wa 88% ISO.
Kagwiridwe ka ntchito ka zinthu zosiyanasiyana zopangira nsungwi kamasiyana kwambiri, Kappa mpaka 11 ~ 16 kapena kuposerapo, ngakhale ndi ECF ndi TCF zoyeretsera ziwiri, zamkati zimatha kufika pa 79% mpaka 85% yokha ya kuyera.
Poyerekeza ndi TCF bamboo pulp, ECF bleached bamboo pulp ili ndi kutayika kochepa kwa bleach komanso kukhuthala kwakukulu, komwe nthawi zambiri kumatha kufika pa 800ml/g. Koma ngakhale TCF bleached bamboo pulp yamakono, kukhuthala kumatha kufika pa 700ml/g yokha. Ubwino wa ECF ndi TCF bleached pulp ndi mfundo yosatsutsika, koma kuganizira bwino za ubwino wa pulp, ndalama zogulira ndi ndalama zogwirira ntchito, bleached bamboo pulp pogwiritsa ntchito ECF bleaching kapena TCF bleaching, sikunatsimikizidwebe. Opanga zisankho zosiyanasiyana zamabizinesi amagwiritsa ntchito njira zosiyanasiyana. Koma kuchokera ku zomwe zikuchitika mtsogolo, bleached bamboo pulp ECF ndi TCF pulking zidzakhalapo kwa nthawi yayitali.
Othandizira ukadaulo wa ECF bleaching amakhulupirira kuti ECF bleach pulp ili ndi khalidwe labwino la pulp, pogwiritsa ntchito mankhwala ochepa, bleaching yabwino kwambiri, pomwe makina a zida ndi okhwima komanso ogwira ntchito bwino. Komabe, ochirikiza ukadaulo wa TCF bleaching amanena kuti ukadaulo wa TCF bleaching uli ndi ubwino wochepa wa madzi otayika kuchokera ku fakitale yoyeretsa, zofunikira zochepa zotsutsana ndi dzimbiri pazida, komanso ndalama zochepa. Mzere wopanga bleaching wopanda chlorine wa sulphate pulp TCF umagwiritsa ntchito njira yoyeretsa yotsekedwa pang'ono, kutulutsa madzi otayika m'fakitale yoyeretsa kumatha kulamulidwa pa pulp ya 5 mpaka 10m3/t. Madzi otayirira ochokera ku gawo la (PO) amatumizidwa ku gawo loyeretsa mpweya kuti agwiritsidwe ntchito, ndipo madzi otayirira ochokera ku gawo la O amaperekedwa ku gawo lotsuka la sefa kuti agwiritsidwe ntchito, ndipo pamapeto pake amalowa mu alkali recovery. Madzi otayirira ochokera ku gawo la Q amalowa mu dongosolo lakunja loyeretsera madzi otayirira. Chifukwa cha bleaching yopanda chlorine, mankhwalawo sawononga, zida zoyeretsera sizifunikira kugwiritsa ntchito titaniyamu ndi chitsulo chapadera chosapanga dzimbiri, chitsulo chosapanga dzimbiri wamba chingagwiritsidwe ntchito, kotero mtengo woyika ndalama ndi wotsika. Poyerekeza ndi mzere wopanga ma pulp wa TCF, ndalama zomwe zimayikidwa mu mzere wopanga ma pulp wa ECF zimakhala zokwera ndi 20% mpaka 25%, pomwe ndalama zomwe zimagwiritsidwa ntchito mu mzere wopanga ma pulp nazonso ndizokwera ndi 10% mpaka 15%, ndalama zomwe zimagwiritsidwa ntchito mu njira yobwezeretsa mankhwala nazonso ndi zazikulu, ndipo ntchitoyo ndi yovuta kwambiri.
Mwachidule, kupanga bleach ya nsungwi ya TCF ndi ECF yoyera kwambiri ya 88% mpaka 90% ya nsungwi yoyera bwino ndizotheka. Pulping iyenera kugwiritsidwa ntchito muukadaulo wozama wa delignification, oxygen deignification isanayambe bleach, kuwongolera bleach mu dongosolo la bleaching la Kappa, bleaching pogwiritsa ntchito njira yoyera ndi njira zitatu kapena zinayi zoyera. Ndondomeko yoyera ya ECF ya bleach ya nsungwi ya OD(EOP)D(PO), OD(EOP)DP; L-ECF bleaching sequence ndi OD(EOP)Q(PO); TCF bleaching sequence ndi Eop(ZQ)(PO)(PO), O(ZQ)(PO)(ZQ)(PO). Popeza kapangidwe ka mankhwala (makamaka kuchuluka kwa lignin) ndi mawonekedwe a ulusi zimasiyana kwambiri pakati pa mitundu yosiyanasiyana ya nsungwi, kafukufuku wokonzedwa bwino ayenera kuchitika pa pulping ndi papermaking ya mitundu yosiyanasiyana ya nsungwi isanamangidwe chomera kuti ipereke chitsogozo pakupanga njira ndi mikhalidwe yoyenera.
Nthawi yotumizidwa: Sep-14-2024
