Liquefaction of sawdust in hot compressed ethanol for the production of bio-oils

Direct liquefaction of lignocellulosic waste (sawdust) has been conducted in hot-compressed ethanol at temperatures from 150 to 250 degrees C. It was found that polyols such as glycerol, glycol and polyethylene glycol (PEG) promoted liquefaction process assisted with hot ethanol treatments seemed promising for production of bio-oils from lignocellulosic materials. Effects of different solvents and catalysts on liquefaction of sawdust were investigated. The results showed that the optimum operating condition for catalytic liquefaction is at 250 degrees C, 1 h of reaction time using glycerol and ethanol as solvent where operating at this condition realized the highest conversion of sawdust which is 97.8%. After reaction, the liquified product was separated by vacuum distillation. ravo fractions were obtained, namely light oil and heavy oil. The properties and compositions of these two fractions were characterized in terms of Fourier transform infrared spectroscopy (FT-IR), gas chromatography-mass spectrometry (GC-MS), size exclusion chromatography (SEC) and nuclear magnetic resonance (NMR). Crown Copyright (C) 2012 Published by Elsevier B.V. on behalf of The Institution of Chemical Engineers. All rights reserved.