Abstract

Liquefaction of lignocellulosic biomass is a promising process to produce liquid biofuels and valuable chemicals. The main purpose of this work is to efficiently liquefy biomass into energy-dense bio-oils through direct liquefaction. Pinewood sawdust was liquefied in supercritical carbon dioxide (SCCO2) at various temperatures (225-375°C) and residence time (0-4 hours) with alkaline catalyst (K₂CO₃). The results showed that the yield of bio-oils varied from 12 wt% to 29 wt% under various conditions. The optimal parameters for SCCO₂ liquefaction were 300°C and 2 hours in this study, which generated the maximum bio-oil yield 29 wt%. The effects of temperature and residence time on SCCO₂ liquefaction process were discussed. Multiple analytical methods such as GC-MS, FT-IR and elemental analyzer were applied to study the compositions and properties of liquid bio-oils.

Keywords: Bio-oils, Biomass, Liquefaction, Supercritical carbon dioxide.