Biofuel production from supercritical water gasification of sustainable biomass

A review of biofuel production from supercritical water gasification (SCWG) of sustainable biomass has been performed, mainly organic waste, following a critical thinking in this field of knowledge. Thus, sub- and supercritical water properties and hydrothermal processing are briefly commented on. Then, the feedstocks usable in SCWG are fully reviewed and a brief description of the studies on the kinetics and mechanisms of reactions is carried out. Next, thermodynamic and process simulation are discussed, aimed at producing liquid and gas biofuels. After that, a brief comment on the viability of SCWG processes to produce biofuels is provided based on techno-economic and lifecycle assessments. Finally, some remarks on where we are and where we should go are given in order to advance this technology towards its maturity. This review explains some misleading concepts applied to SCWG processes, provides a brief but comprehensive overview of the technology focused on producing biofuels in a sustainable way, allows a better understanding of the SCWG of biomass for biofuel production, and proposes a series of improvements to be made and examined in the future research.