摘要
在保温温度170℃、保温时间90 min、乙醇浓度50%的条件下对大豆秸秆进行乙醇预处理,并对预处理后大豆秸秆进行成分分析,发现乙醇预处理主要脱除了大豆秸秆中的半纤维素和木素(脱除率分别为82.9%和62.0%)。动力学研究发现,乙醇预处理脱木素反应为一级反应,脱木素过程由大量脱木素段和补充脱木素段组成,且预处理反应进入补充脱木素段的温度要高于160℃。在保温温度为170℃时,大量脱木素段和补充脱木素段的木素脱除率分别为87.9%和12.1%。大量脱木素段主要脱除的是小分子木素(相对分子质量为9101);而补充脱木素段脱除的木素的相对分子质量较大,达到12961。对比2个阶段的木素脱除速率发现,大量脱木素段的脱除速率(k_大=4×10^(-4)s^(-1))高于补充脱木素段(k_补=4×10^(-5)s^(-1)),说明大量脱木素段木素脱除速率较快。
It is an essential step to destroy the structure of the cell wall by pretreatment before enzymatic hydrolysis for the conversion of lignocellulose to ethanol.Ethanol pretreatment has many advantages,and is a hot research topic in recent years.In this experiment,soybean stalk was pretreated under the following condition：heat preservation temperature 170℃,holding time 90 min,ethanol concentration 50%.The component analysis of pretreated material indicated that the hemicellulose and lignin in soybean stalk were mainly removed by ethanol pretreatment （The removal ratio reached 82.9% and 62.0% respectively）.Delignification reaction during ethanol pretreatment was a first order reaction.The kinetics study showed that there were two delignification stages i.e.bulk delignification and supplement delignification when the temperature was above 160℃.Lignin was removed 87.9% and 12.1% respectively in the two steps when the temperature was 170℃.The removed lignin in the two stages had different molecular weight （Mw =9101 and 12961）.In these two delignification stages,lignin removal rate in bulk delignification stage was higher （Kbulk =4 ×10^-5^s-1 〉 ksupplement =4 ×10^-5^s-1）.
出处
《中国造纸学报》
CAS
CSCD
北大核心
2017年第1期1-6,共6页
Transactions of China Pulp and Paper
基金
国家自然科学基金(31500496)
湖北省教育厅重点项目(D20161402)
制浆造纸科学与技术教育部重点实验室开放基金(KF201611
KF-201409)
关键词
大豆秸秆
乙醇预处理
脱木素
动力学
soybean stalk
ethanol pretreatment
delignification
kinetics
