I. Txheej txheem cej luam ntawm Anaerobic Digestion
Anaerobic digestion yog ib txoj kev kho mob lom neeg uas siv cov kab mob enzymatic los degrade cov organic teeb meem. Thaum xub thawj, cov cuab yeej no tau siv tsuas yog hauv nroog cov chaw kho dej khib nyiab los kho cov sludge los ntawm thawj cov dej xau thiab cov sludge ntau dhau. Nrog rau kev txhim kho thev naus laus zis, nws cov nqi hauv kev kho cov dej khib nyiab thiab kev siv cov peev txheej tau raug tshuaj xyuas dua.
II. Mechanism ntawm Anaerobic Digestion
Anaerobic digestion yog ib tug complex biochemical txheej txheem. Los ntawm kev xav fermentation, nws tuaj yeem muab faib ua peb theem; los ntawm kev pom microbiological, nws feem ntau muab faib ua ob theem ua haujlwm.
1. Peb theem ntawm txheej txheem fermentation
Acidic Fermentation Stage: Thaum lub concentration ntawm cov organic teeb meem nyob rau hauv cov dej khib nyiab yog siab dhau lawm thiab yaj cov pa oxygen depleted, tsim ib lub xeev anaerobic, carbohydrates sai decompose, ua cov fatty acids qis xws li acetic acid, propionic acid, thiab butyric acid. Lub sijhawm no, tus nqi pH sai sai poob rau 5.0-6.0, thiab cov dej khib nyiab tso tawm cov ntxhiab tsw muaj zog.
Theem Txo Acidity: Organic acids thiab nitrogenous compounds pib decompose, tsim cov khoom xws li ammonia thiab amines. Lub pH maj mam nce mus rau 6.0-6.5, thiab BOD nce mus txog qhov siab tshaj plaws, nrog rau cov foaming thiab khoom ntab.
Alkaline fermentation theem: Qhov no yog theem kawg ntawm kev zom. Accumulated organic acids yog decomposed rau hauv methane, carbon dioxide, thiab ammonia, thiab yuav luag tag nrho cov fiber thiab nitrogen-muaj cov organic teeb meem yog decomposed. Lub sijhawm no, pH nce siab tshaj 7.5, BOD poob qis, thiab cov txheej txheem zom zaub mov tiav.
2. Ob theem hauv microbiology
Theem 1 (Acid production stage): Nyob rau hauv qhov kev txiav txim ntawm cov kua qaub- tsim cov kab mob (facultative thiab obligate anaerobes dav pom nyob rau hauv cov xwm), cov organic teeb meem decomposed rau hauv qis fatty acids, aldehydes, cawv, thiab lwm yam. Acid- tsim cov kab mob reproduces sai thiab yog heev adaptable rau ib puag ncig.
Theem 2 (Methane fermentation stage): Methanogens siv cov khoom ntawm thawj theem, decomposing rau methane thiab carbon dioxide. Methanogens yog lub luag haujlwm anaerobes nrog tus nqi qis heev thiab muaj kev nkag siab zoo rau ib puag ncig (pH, kub, tshuaj lom).
Cov ntsiab lus tseem ceeb ntawm kev tswj hwm: Qhov kev tswj hwm rau kev zom zaub mov anaerobic yog qhov kev loj hlob ntawm methanogens. Nyob rau hauv tas li fermentation, liquefaction thiab gasification yuav tsum muaj ib tug dynamic tshuav nyiaj li cas. Yog hais tias ib puag ncig cuam tshuam, methane fermentation nres, ua rau tsub zuj zuj ntawm cov roj fatty acids thiab ua rau kev zom zaub mov tsis zoo.
III. Qhov zoo thiab qhov tsis zoo ntawm anaerobic digestion
Txawm hais tias kev zom zaub mov anaerobic muaj qee qhov kev txwv hauv daim ntawv thov muab cov qauv tseem ceeb tam sim no hauv kev kho cov khib nyiab organic rau lub cev qhuav dej, ziab, lossis kev ua kom qhuav, nws qhov tshwj xeeb zoo ua rau nws tseem ceeb hauv lub zog tam sim no - ib puag ncig tsis tshua muaj.
1. Kev soj ntsuam tsis zoo
Effluent yuav tsum tau kev kho mob theem nrab: Lub concentration ntawm cov organic residual nyob rau hauv lub digestive sib cais kua tseem siab, yuav tsum tau kev kho mob ntxiv.
Teeb meem tsw: Sulfur thiab nitrogen{0}}muaj cov dej khib nyiab ua rau hydrogen sulfide thiab ammonia thaum lub sij hawm decomposition reductive, emissions foul.
Kev txwv nyiaj txiag: Kev zom zaub mov anaerobic tsis yog kev lag luam rau cov dej khib nyiab qis qis.
2. Kev soj ntsuam zoo
Kev txuag hluav taws xob: Cov biogas uas tsim tawm tuaj yeem siv los ua roj, nrog rau cov nqi hluav taws xob tsuas yog ib qho -feem kaum ntawm cov roj ntsha oxidation.
Tsawg thiab ruaj khov sludge ntau lawm: Tus nqi ntawm cov sludge tshaj yog me me, nrog zoo heev thickening thiab dewatering zog; cov sludge digested yog hygienically thiab chemically ruaj khov thiab yuav siv tau raws li pov tseg los yog tsiaj pub.
Muaj peev xwm kho tau siab: Nws muaj qhov cuam tshuam liquefaction tseem ceeb ntawm cov khib nyiab hauv cov dej khib nyiab.
Kev ua haujlwm thiab khoom siv tau zoo: Cov cuab yeej muaj cov qauv yooj yim, ua haujlwm hauv lub kaw lus kaw tsis muaj ntxhiab tsw phem, thiab yuav tsum tsis muaj kev txawj tshwj xeeb los ua haujlwm.
Kev nthuav dav thev naus laus zis: Nrog rau kev txhim kho ntawm anaerobic activated sludge thiab fluidized txaj txheej txheem, cov cuab yeej no maj mam dhau los siv rau kev kho cov dej khib nyiab qis, thiab nws cov kev lag luam yuav tsum txhim kho.