Energy Conversion and Management, Volume 93, 2015, Pages 23–30.
Rundong Li, Yinghui Xie, Tianhua Yang, Bingshuo Li, Weidan Wang, Xingping Kai
College of Energy and Environment, Shenyang Aerospace University, Key Laboratory of Clean Energy, Liaoning Province, No. 37 Daoyi South Avenue, Daoyi Development District, Shenyang 110136, Liaoning, China
The production of bio-oils by hydrothermal liquefaction of lignocellulose is an attractive prospect. However, bio-oils produced using traditional methods have multiple components and are low grade, which limit their application. In this study, a new method was proposed to improve the quality of bio-oils. Chemical–Biological pretreatment (CB-pretreatment) was performed on fresh corn stalks to separate a partial lignin and to convert hemicellulose, generating ethanol for hydrothermal liquefaction and improving the quality of the resulting bio-oils. Furthermore, the influence of CB-pretreatment on the components of lignocellulose in corn stalks and the pretreated samples was analyzed. And the materials and bio-oils were analyzed with TGA and GC–MS. The results showed that the relative content of lignin reduced from 13.25 ± 0.87% to 8.97 ± 0.77% in the alkaline treatment. And the relative content of hemicellulose in the alkaline-acid pretreated substrates decreased from 21.65 ± 0.74% to 10.06 ± 0.48%. After the whole pretreatment, the concentrations of ethanol and remaining reducing sugar in the fermented liquor were 2.88 ± 0.09 mg/mL and 3.59 ± 0.30 mg/mL, respectively. Moreover, the pretreated substrates had a lower degradation temperature and less ash content than the corn stalks. The heating value of the bio-oil was 32.21 MJ/kg. Moreover, the number of bio-oils components was obviously reduced. Toluene and 2,6-di-tert-butyl-4-methylphenol, which are respectively used as high octane additive and antioxidant in fuels increased significantly in quantity, with their total percentage of corresponding peak area reaching 30.77%.