Upgrading Fast Pyrolysis Oil with Vacuum Gas Oil by Catalytic Hydrodeoxygenation in Supercritical Ethanol

This work demonstrated an effective approach to upgrading bio-oils by upgrading pyrolysis bio-oil with vacuum gas oil (VGO) by catalytic hydrodeoxygenation (HDO) in supercritical ethanol with both hydrogen gas and formic acid as the in situ hydrogen source. The effects of supercritical ethanol, bio-oil/VGO mass ratio, reaction temperature, hydrogen source, and reaction time on co-upgrading pyrolysis bio-oil with VGO over Ru/Al 2 O 3 were investigated in this study. Crude bio-oil, crude VGO, and co-upgraded oils were characterized comparatively for their physical/chemical properties and compositions. It was found that the optimal reaction conditions of co-upgrading bio-oil with VGO were at a 4:1 mass ratio, in supercritical ethanol, with hydrogen gas as the hydrogen source, and at 350 °C for 2 h over the Ru/Al 2 O 3 catalyst. The obtained co-upgraded oils have improved thermal stability and homogeneity, which could be used as an environmentally friendly and sustainable feed for large-scale upgrading in a petroleum refinery.