Recent advances in co-thermochemical conversions of biomass with fossil fuels focusing on the synergistic effects

Biomass is vital for future energy use, but several disadvantages obstruct its commercial applications. Co-thermochemical conversions of biomass and fossil fuels are alternative methods for offsetting the disadvantages of biomass and improving the quality of bio-oil. This paper overviewed the state-of-the-art research and development of co-thermochemical conversions of biomass and fossil fuels (i.e., coal, oil sand and oil shale). Emphasis was placed on different types of feedstocks, three thermochemical conversion methods (i.e., co-pyrolysis, co-gasification and co-liquefaction) and the synergistic effects. Furthermore, the influencing factors, advantages and disadvantages, and the possible mechanisms related to these co-thermochemical conversion technologies are discussed. The current developments and prospects for co-thermochemical conversions of biomass and fossil fuels are also proposed.