Hydrothermal and solvothermal processes for renewable fuels

Biomass, whether energy crops or residues from agriculture, is a renewable source of energy. Modern society uses liquid and gaseous fuels as energy carriers, so biomass conversion to these fuels is an integral part of a sustainable energy future. Solvothermal processes, which involve the simultaneous action of a solvent and elevated temperature, perhaps along with a catalyst, can do this necessary conversion. This lecture will describe our recent work in converting biomass to gases and bio-oils and the subsequent upgrading of the bio-oil to liquid hydrocarbons. We have examined the hydrothermal liquefaction and gasification of microalgae, the hydrothermal gasification of lignin and cellulose, the esterification of oleic acid in supercritical ethanol, and the hydrothermal catalytic deoxygenation of fatty acids. In each of these systems, the fluid (water or ethanol) serves not only as the solvent but also as a key reactant in the process.