Catalytic hydrothermal liquefaction of lignocellulosic biomass for biocrude production and process optimization

Abstract Hydrothermal liquefaction is a promising technology to process wet lignocellulosic biomass, without the need for the energy intensive drying process. The objective of this study is to explore the recovery of biocrude from lignocellulosic biomass (orange peel, dairy manure, and food waste) with and without the addition of catalyst and the optimization of process parameters in terms of both biocrude quantity and quality. Potassium alkali catalysts were more effective in the chemical degradation of biomass to biocrude and the orange peel sample showed a higher energy recovery of about 54.4% under both catalytic and non‐catalytic conditions compared to dairy manure (36%) and food waste (28.5%). The ideal parameters for achieving the highest biocrude yield (32% by weight) were determined to be a temperature of 250°C, a total solids concentration of 25%, the addition of 3% K 2 CO 3 , and a reaction time of 30 min. The extracted biocrude exhibited fuel characteristics similar to those of diesel and biodiesel, with a higher heating value between 32 and 38 MJ/kg and a flash point ranging from 90 to 108°C. The distillation of biocrude showed a higher diesel distribution of 45% with the boiling range between (270–345°C), which falls within the typical boiling range of conventional diesel fuels. This indicates that a significant fraction of the biocrude can be directly utilized or further refined as a substitute for petroleum‐based diesel, enhancing its viability as a renewable transportation fuel.