【作者】 栗薇；

【导师】 吴正舜；

【作者基本信息】 华中师范大学 ， 应用化学， 2007， 硕士

【摘要】 利用废弃纤维类原料制取燃料酒精是目前全球范围研究和应用的热点。本文以木屑和谷壳作为纤维类原料，对其制取燃料酒精过程中的预处理工艺和酶水解工艺进行了研究。纤维素原料在水解前经过预处理可除去木质素、溶解半纤维素或破坏纤维素的晶体结构，从而增大其可接近表面，提高水解产率。通过对谷壳、木屑稀酸预处理的研究，考察了酸种类、固液比、反应时间、温度、酸浓度对预处理的影响。实验研究结果表明，谷壳在2％（w／w）H₂SO₄、105℃、3小时的条件下有利于其预处理，原料中半纤维素含量比未处理时降低了74.2％，木质素含量降低了18％，而纤维素则增加了15％；而木屑在2％（w／w）HCl、105℃、反应3小时的条件下预处理较有利，原料中半纤维素含量比未处理时降低了78.4％，木质素含量降低了29.3％，纤维素含量增加了28.6％。同时对预处理后的谷壳、木屑进行酶水解研究，研究了pH、温度、时间、酶用量对酶水解的影响及水解后原料组分及物理微观形态的变化，实验研究结果表明，pH=4.8，50℃，反应48小时，纤维素酶用量20FPA／g（谷壳），酶水解最有利于纤维素转化为葡萄糖。酶水解后，谷壳中纤维素含量降低了72％，木屑中纤维素含量降低了65.4％。扫描电镜观察原料形态变化。谷壳用氢氧化钙预处理的研究结果表明，氢氧化钙80℃预处理谷壳6天时，溶解性大约增加了50％，氢氧化钙的用量是0.167g，原料中木质素的含量是9.3％，降低了62.4％，而纤维素仍有90.8％保留在原料中，半纤维素经80℃预处理4天后其含量稍微降低。氢氧化钙80℃预处理6天的谷壳在纤维素酶用量20FPA／g（谷壳），温度50℃，水解48h的条件下水解，酶水解率达到84.2％。更多还原

【Abstract】 It has been the hotspot of study and application in last decades in the world, which is using lignocellulose to ethanol. In the paper, we study pretreatment and enzymatic technics on lignocellulose to ethanol with wood and rice hull as materials.Before enzymatic hydrolysis, by pretreating lignocellulose may remove lignin, dissolve hemicellulose or destroy crystal configuration of cellulose, for aggrandizing approachability surface, improving yield of hydrolysis. The influential factors of dilute acid pretreated rice hull and wood were studied including acid kinds, the ratio of solid to liquid, reaction time, temperature, acid concentration. Experimental results showed that: rice hull was favorable at 2 %（w/w） H₂SO₄、105℃、3 h, the content of hemicellulose and lignin in rice hull reduced 74.2 % and 18 % individually, the content of cellulose increased 15 %. But pretreatment of wood was advantageous at 2 %（w/w） HCl、105℃、3 h, the content of hemicellulose and lignin in wood reduced 78.4 % and 29.3 % individually, the content of cellulose increased 28.6 %. Then the enzymatic hydrolysis of rice hull and wood pretreated was studied. The influential factors of enzymatic hydrolyzing were pH, cellulose loading （FPA/g cellulose）, hydrolyzing temperature, time of enzymatic hydrolysis, and the changes of material component and physics microcosmic configuration were observed. Experimental results showed that: at pH=4.8, 50℃, 48 h, 20 FPA(g rice hull^-1), cellulose of enzymatic hydrolysis was propitious to translate into glucose. After enzymatic hydrolysis, the content of cellulose felled 72 % in rice hull, the content of cellulose felled 65.4 % in wood.The result of rice hull pretreated with lime indicated that: rice hull with lime pretreated 6d at 80℃, the solubilization of rice hull increased about 50 %, the lime consumption was 0.167 g, the content of lignin was 9.3 %, reduced 62.4 %. But 90.8 % of cellulose retained in the rice hull, the content of hemicellulose little reduced after pretreated 4 d at 80℃. At 50℃, 48 h, 20 FPA (g rice hull^-1), the yield of enzymatic hydrolysis of rice hull with lime pretreated 6d at 80℃was 84.2 %.更多还原