甜高粱茎秆固态发酵制取燃料乙醇过程分析与中试研究

STUDIES ON THE PROCESS PARAMETERS OF SOLID STATE FERMENTATION FOR FUEL ETHANOL PRODUCTION FROM SWEET SORGHUM STALKS AND PILOT TEST

研究了甜高粱秆固态发酵生产燃料乙醇过程工艺参数的变化规律及相关性,并以此为基础进行了5m^3转鼓式固态发酵反应器中试试验。结果表明:糖份的快速消耗伴随着乙醇的大量产生,酵母分泌相关酶类使非还原糖向还原糖转化;发酵过程pH下降,对乙醇产生无明显抑制;搅拌可以改善传质、传热,有利于菌体的生长和发酵的进行。中试结果表明40～44h内可完成发酵。直接固态发酵与蒸馏后获得30%～40%的粗醇溶液,平均13.5～15.5kg甜高粱秆产1kg(99.5%)无水乙醇,糟渣粗蛋白含量6.94%(干基),可替代"黄储"饲料。糖利用率最高97.50%,乙醇实际收率最高94.48%。

The variation and correlation of process parameters in solid state fermentation for ethanol from sweet sorghum stalks were investigated.According to the results of shaking flask experiment and 10L bioreactor experiment,a pilot plant for ethanol production from sweet sorghum stalks via solid state fermentation was built.The results indicated that sugars were consumed connecting with the increase of ethanol content.The non-reducing sugar was converted to the reducing sugar with enzymes secreted by yeast in initial stage of fermentation;pH decreased during fermentation process and had no impacts on ethanol production.Stirring could improve mass and heat transfer,mitigate the adverse effects caused by high temperature and reduced dissolved oxygen yeast growth and ethanol yield.The solid-state fermentation could be completed within 40～44h in the pilot test.The crude ethanol of 30%-40%（v/v）was obtained via solid-state distillation.13.5-15.5kg of sweet sorghum stalks on average were used to produce 1kg of（99.5%）anhydrous ethanol; The distillers contain 6.94% proteins which can be used as yellow fodder.The maximum ethanol yield of 94.48% and sugar utilization of 97.50% were obtained,respectively.