Experiment on Microwave Pyrolysis of Biomass Induced by Compound Absorber

Bio-oil organic phases were prepared by microwave pyrolysis of biomass with the compound absorber of TiC/SiC. The effects of mass ratios of TiC to SiC, absorber to biomass and microwave power to biomass on the yield of organic phase were analyzed by response surface methodology. The effects of pure SiC and compound absorber on the yields and chemical compositions of organic phase were analyzed and compared under the optimal conditions, and the characterization and analysis of bio-char were also carried out, to explore the properties and potential of organic phase and bio-char. The results showed that all factors had obvious effects on organic yield with interactions between the factors. The optimal yield was 28.60% under conditions of TiC to SiC mass ratio of 20%, absorber to biomass mass ratio of 53% and microwave power to biomass mass ratio of 9.5 W/g, which was similar to the predicted value of 28.69%. When the pure SiC was used under the optimal conditions, the organic yield was reduced to 23.35%. The pyrolysis products from cellulose and hemicellulose could be retained more by introducing appropriate amount of TiC, which could increase the organic yield and reduce the relative content of acids, ketones and phenols at the same time. A relatively large number of furans, alcohols and phenols and their relatively concentrated carbon atom distribution made organic phase have high potential as chemical raw materials. The NMR analysis showed that the ratio of aliphatic hydrogen/carbon to aromatic hydrogen/carbon in organic phase obtained by using compound absorber was increased significantly, which verified the accuracy of the analysis. In addition, the bio-char obtained by using the compound absorber had higher carbonization degree and adsorption performance, and its specific surface area and pore volume were 360 m2/g and 0.22 cm3/g respectively. It had high potential to make active materials. The research result provided experimental and theoretical basis for further industrial application research. © 2020, Chinese Society of Agricultural Machinery. All right reserved.