(412c) Bio-Oil Production and Catalytic Upgrading to Transportation Fuels

Abstract

Increasing fossil fuel prices and the demands of clean energy have accelerated research on renewable new energy sources. Bio-oil (also known as pyrolysis oil) which can be derived from lignocellulosic biomass by fast pyrolysis process has the potential to be substitute for petroleum-drived transportation fuels. In addition, with numerous combustion tests, it has been shown that bio-oil can be burned efficiently in internal combustion engine without any major modification. However, due to its high acidity (PH: 2-3), high oxygen (30-60wt %) and water (15-30 wt %) contents, bio-oil has lower energy density (15-19 MJ/kg), compared with petroleum (40MJ/kg). Furthermore, bio-oil is thermal unstable that tends to age and results in phase separation at room temperature. Therefore, upgrading of bio-oil is necessary before it can be used as a transportation fuel.

The high oxygen content of bio-oil imparts undesirable properties. To upgrade bio-oil, several metal catalysts such as NiCl_2, Ru, Rh and CoCl₂ supported on γ-Al₂O₃, C and SiO₂, slurried in polyethylene glycol solvent, were evaluated at 150 - 270^oC and in the presence of H₂, bio-oil was deoxygenated by a combination of hydrodeoxygenation and decarboxylation reactions while oxygen is removed as H₂O and/or CO₂. Gas analysis of the reactor yielded: CO₂ (11%) and CH₄ (0.84%), indicating that some oxygen was efficiently removed from the bio-oil partly. The GC-MS analysis showed that propylene glycol and hexadecane were produced as the major products.