Utilizing cocoa bean husk residues from supercritical extraction for biofuel production through hydrothermal liquefaction

This study aimed to develop an efficient method for converting residual biomass into biofuel through a process that combines supercritical fluid extraction and hydrothermal liquefaction. The study analyzed the compositional changes in the biomass residues using various co-solvents and assessed their potential for biofuel production. After hydrothermal liquefaction, the liquid biofuel produced showed a decrease in the H to C ratio from 1.7 to 1.6 and a reduction in the O to C ratio from 0.5 to 0.2, compared to the unprocessed feedstock, indicating a favorable alteration in elemental composition for biofuel production. Notably, residues extracted with supercritical CO₂ and ethanol had the lowest yield, while those extracted with CO₂ and water achieved the highest energy recovery at 101.5 %. These findings suggest that integrating supercritical fluid extraction with hydrothermal liquefaction is an environmentally sustainable and efficient approach, significantly advancing the development of sustainable biofuels.