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.
Xia XU Yun WU Yong ZHAO Hongqiang LI Min PENG Jian XU
. Degradation of corn stover components with microwave torrefaction[J]. The Chinese Journal of Process Engineering, 2019
, 19(S1)
: 109
-114
.
DOI: 10.12034/j.issn.1009-606X.219160
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