Biomass to Biocrude: A Brief Review of Catalytic Liquefaction

Abstract

Biomass energy is the largest source of renewable energy, accounting for approximately 55% of global renewable energy consumption. Therefore, it holds great importance for the efficient utilization of biomass. Hydrothermal liquefaction (HTL) has been demonstrated to convert biomass into liquid biofuels, with physicochemical properties comparable to conventional crude oil. Because moisture content is a key factor in choosing the best conversion method, HTL is especially well-suited for fresh biomass, which usually contains a substantial amount of moisture. This comprehensive review examines the research progress in biomass hydrothermal liquefaction, focusing on biomass types, liquefaction parameters, reactor configurations, and catalyst types, with particular emphasis on a comparative analysis of catalytic mechanisms. This study provides a structured framework for selecting optimal conversion processes by linking biomass types, parameters, reactors, and catalysts. Future research should prioritize the development of cost-efficient bifunctional catalysts and optimization of continuous reaction systems with respect to heat and mass transfer efficiency, and integration design of catalysts, while also aiming to minimize byproduct handling costs.