In order to improve the enzymatic saccharification ratio of straw when producing biomass ethanol, rice straw was pretreated with ethanol-phosphoric acid solution at the normal temperature and pressure. The effects of temperature, ethanol volume fraction, time and the recycled ethanol-phosphoric acid solution on enzymatic saccharification ratio of rice straw were investigated. The results showed that the enzymatic saccharification ratio of rice straw increased from 10.03% to 57.75% when the volume fraction of ethanol was 50% (v/v), the pretreated temperature was50℃ and the pretreated time was 60 min. The enzymatic saccharification ratio of straw pretreated with the recycled ethanol-phosphoric acid solution was reached 56.89%, and close to saccharification ratio of straw pretreated with ethanol-phosphoric acid. The pretreatment with the recycled ethanol-phosphoric acid solution was able to reduce energy consumption and save operating cost with reducing the number of recycling ethanol by distillation. The physical structure and chemical properties of rice straw were changed after pretreated. The crystalline structure of rice straw was destroyed during the process of pretreatment, and its specific surface area and porosity increased. The pretreated straw was easily hydrolyzed by hydrolytic enzymes or microbe. Ethanol, lignin, phosphoric acid and other useful materials in filtrate solution were easily separated by distillation and centrifugation. The research could provide a circulatory pretreatment way of straw under mildness conditions was obtained.%为了提高制生物质酒精时稻草酶解糖化率,该文采用常温常压乙醇-磷酸预处理稻草.研究了预处理温度、乙醇体积分数、预处理时间对稻草糖化率的影响以及最优条件下的回用乙醇-磷酸预处理稻草糖化效果.结果表明,在50℃、乙醇体积分数50％、处理时间60 min条件下,稻草酶解糖化率从10.03％提高到57.75％.回用乙醇-磷酸预处理后稻草糖化率达到56.89％,与乙醇-磷酸预处理后糖化率相接紧,可减少蒸馏回收乙醇次数,降低能量消耗,节省运行费用.对比预处理前后稻草物理和化学性质的变化表明,乙醇-磷酸预处理使稻草的晶状结构遭到破坏、孔隙度增加、比表面增大,易于被微生物或酶酶解.乙醇-磷酸预处理后的过滤液容易通过蒸馏、离心、过滤等方式分离得出乙醇、木质素、磷酸等有用原料.该研究提供了一种温和条件下可运用于循环生产的稻草预处理方法.
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