用微波可高效对生物质烘焙预处理，考察了不同微波烘焙过程对玉米秸秆主要组分的降解作用及酸、碱、甘油催化剂对纤维素转化效率的影响，并对预处理的玉米秸秆进行酶解实验。结果表明，单纯的微波预处理对玉米秸秆中主要组分纤维素、半纤维素和木质素均有强烈的转化作用。无催化剂微波烘焙后，样品中纤维素含量降低了30%。在微波烘焙中添加酸、碱、甘油催化剂，可选择性降解玉米秸秆中的半纤维素或木质素，有效提高预处理后玉米秸秆中的纤维素含量，添加NaOH后纤维素含量增加最明显，由33%增至42%，纤维素最高转化率达65%。
As an indispensable step in biomass utilization chain, the current pretreatment methods cannot meet the industrial production requirements of low cost, low pollution and high efficiency. New technology development is necessary. In this work, microwave irradiation-based torrefaction pretreatment was employed to investigate the degradation of the major components in corn stover with or without catalysts. In addition, the destruction and change of corn stover structure before/after pretreatment and enzymatic hydrolysis were also studied. The results showed that the monomers of the three major components (cellulose, hemicellulose and lignin) were transformed dramatically with microwave treatment. However, they were not degraded from the polymer structure. With the presence of catalysts, the microwave torrefaction presented selective degradation effect on corn stover. The addition of acid, alkali or glycerol in the pretreatment process increased the content of cellulose. NaOH was observed to be the most effective catalyst. The cellulose content increased from 33% to 42%. The contents of other components in the solids were significantly reduced. Enzymatic hydrolysis experiments on the corn stover obtained from different pretreatments. After microwave torrefaction for 20 min, the yield of glucose increased from 12% to 17% with the enzymatic hydrolysis rate of cellulose increased from 33% to 65%. NaOH as a catalyst in the pretreatment process could significantly improve the enzymatic hydrolysis rate of cellulose. The glucose yield was increased from 12% to 30%. While the enzymatic hydrolysis of the corn stover pretreated with sulfuric acid or glycerol presented a slight effect or no effect. Microwave torrefaction increased temperature without the use of pressure vessels and organic solvents compared to single microwave irradiation process. Due to the unique advantage such as easy operation and less energy consumption, the microwave torrefaction can be developed into a practical and efficient biomass pretreatment technology.
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