Stepwise Enrichment of Sugars from the Heavy Fraction of Bio-oil

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• 作者：Shurong Wang ; Yurong Wang ; Furong Leng ; Junhao Chen
• 刊名：Energy & Fuels
• 出版年：2016
• 出版时间：March 17, 2016
• 年：2016
• 卷：30
• 期：3
• 页码：2233-2239
• 全文大小：360K
• ISSN：1520-5029

文摘

Sugars are among the main compounds in bio-oil produced by biomass pyrolysis. However, they can easily form coke, resulting in fast deactivation of the catalyst and severe blockage of the reactor during catalytic upgrading of bio-oil. Molecular distillation may be performed to retain sugars and pyrolytic lignin in the heavy fraction and thus to provide a primary stage for the subsequent sugar separation and utilization. A new method involving extraction, heat treatment, and column chromatography was introduced to separate further the aqueous phase obtained from the bio-oil heavy fraction by methanol–water extraction. Thus, monophenols and sugars were coextracted through these combined separation technologies. A fraction rich in monophenols was obtained by solvent extraction. Other impurities were further removed by heat treatment and column chromatography. An alcohol sedimentation method further separated the combined sugar-rich fraction into an ethanol-soluble fraction (SF-1) and an ethanol-insoluble fraction (SF-2). Gas chromatography–mass spectrometry, Fourier transform infrared spectroscopy, nuclear magnetic resonance spectroscopy, and high-performance liquid chromatography were performed to characterize sugars in the obtained fractions. SF-1 mainly contained monosaccharides such as levoglucosan, glucose, and xylose, whereas SF-2 still had a small amount of cellobiose besides monosaccharides. The ultimate recovery rates for several identified monosaccharides were in the range of 75–86 wt %.