Effects of type of solvents (hydro-treated bio-oil and ethanol) and temperature (300 and 350 °C) on hydrodeoxygenation (HDO) of fast pyrolysis oil (PO) were studied. The presence of a solvent effectively reduced self-polymerization of the intermediates during the bio-oil HDO process. HDO of PO using hydro-treated oil as the solvent produced higher yields of oil fraction (OF) and consumed more H2 than those with ethanol. While the OF yields from all the HDO experiments ranged from 60 to 90 wt%, the highest OF yield was obtained using hydro-treated bio-oil as the solvent. Nevertheless, HDO of PO in ethanol is more promising as it improves the HHV (higher heating value) of the bio-oil substantially (from 21 to 38 MJ/kg), reduces the molecular weight of bio-oil, and the resulted OFs have the lowest O/C value (0.08). HDO upgrading of bio-oil in ethanol has similar effects as HDO operation at a higher temperature (350 °C) without solvent with respect to molar mass reduction for the bio-oil.
- Ethanol solvent
- Fast pyrolysis oil
- Hydro-treated bio-oil solvent
- Hydrodeoxygenation (HDO)
- Ru/C catalyst