Citric acid tuaj yeem muab rho tawm los ntawm cov txiv hmab txiv ntoo xws li txiv qaub thiab txiv kab ntxwv, nrog rau kev tsim los ntawm oxaloacetic acid thiab ethylene ketone. Txawm li cas los xij, txoj kev tsim khoom lag luam tam sim no siv hauv tsev thiab thoob ntiaj teb yog txhua txoj kev fermentation. Muaj cov khoom fermentation, ntiav phaj fermentation, thiab sib sib zog nqus fermentation txheej txheem nyob rau hauv fermentation txoj kev. Ntau tshaj 80% ntawm citric acid nyob rau hauv Tuam Tshoj yog tsim los ntawm qhuav qos yaj ywm hmoov los ntawm sib sib zog nqus fermentation los ntawm Aspergillus niger, neutralization nrog calcium carbonate, sulfuric acid hydrolysis, refining, concentration, crystallization, thiab ziab.
(1) fermentation yuav tsum sib tov qhuav qos yaj ywm hmoov rau hauv ib lub slurry ntawm 18% mus rau 22%, uas yog ces xa mus rau ib tug steam sterilized (0.2MPa, 40-60min) fermentation tank. Tshav kub nrog chav rau 110 degree thiab sterilize rau 20 feeb, ces liquefy nrog 0.05% amylase. Tom qab txias rau 35 degree, inoculate nrog Aspergillus niger rau fermentation. fermentation kub yog 36-38 degree nyob rau hauv thaum ntxov theem thiab 34-36 degree nyob rau hauv lub tom ntej theem; Qhov cua qhov cua yog 1: (0.1-0.2); pH tus nqi yuav tsum tsis txhob qis dua 2.5; Lub voj voog fermentation yog 96 teev. Cov kua qaub ntau lawm yog 10% mus rau 14%, thiab hloov pauv tus nqi yog 95%.
(2) Tom qab qhov nruab nrab fermentation tiav lawm, kub lub fermentation broth mus rau 8 0 degree kom tshem tawm pwm, thiab ces xa mus rau lub phaj ncej rau siab pom kom tau ntshiab kua. Ntxiv cov hmoov calcium carbonate rau hauv qhov pom ntawm 80 degree thiab neutralize nws mus rau pH tus nqi ntawm 5.0-5.5, thiab ua kom sov li 0.5 teev. Tom qab ntawd, tom qab lub tshuab nqus tsev pom, ntxuav nrog dej kub 80 degree kom tau txais calcium citrate.
(3) Acid hydrolysis thiab refining yog ua los ntawm kev nplawm tas li, ntxiv calcium citrate rau hauv dej los yog dilute acid, ces maj mam ntxiv sulfuric acid kom txog rau thaum tus nqi pH nce mus txog 1.8, cua sov rau 9 0 degree, thiab txiav txim siab qhov kawg siv. txoj kev ob lub raj. Tom qab ntawd ntxiv 1% mus rau 3% activated carbon nrog citric acid cov ntsiab lus, ua kom sov rau 0.5 teev, muab tso rau hauv lub tshuab nqus tsev lim kom qhuav, thiab ntxuav cov kua qaub nrog dej kub 90 degree kom txog thaum cov kua qaub seem. qis dua 0.5%. Cov dej ntxuav (xws li dilute acid) yog siv rau cov kua qaub hydrolysis tom ntej. Thaum kawg, siv 732 cationic resin rau ion pauv kom tshem tawm ntau yam cations.
(4) Cov concentrated, crystallized, thiab qhuav ntshiab kua tom qab ion pauv muaj kwv yees li 15% mus rau 20% citric acid. Ua kom pom tseeb hauv lub tshuab nqus tsev ntawm 55-600 degree C mus rau qhov sib txheeb ze ntawm 1.335-1.340 thiab tso rau hauv lub lauj kaub crystallization. Txias nrog cov dej ntsev khov kom qis dua 36.6 degree kom precipitate dej crystals. Tom qab sib cais cov muaju, ntxuav nrog me me ntawm cov dej distilled kom txog thaum cov ntsiab lus sulfuric acid yog 200 × Hauv qab 10 ntiv tes, thaum kawg qhuav nrog cua kub ntawm 35 degree kom tau cov khoom tiav.
