Co-hydrothermal liquefaction of waste biomass: Comparison of various feedstocks and process optimization

Abstract

Hydrothermal liquefaction (HTL) is a promising method for converting biomass into biocrude, utilizing moderate temperatures (250–350 °C) and high pressures (10–25 MPa) near the solvent's critical point, typically water. This study assesses various waste biomass feedstocks under identical HTL conditions (T = 280 °C, P = 12 MPa, time = 30 min). Mustard meal exhibited the highest biocrude yield (38 wt%), followed by canola meal (27 wt%), attributed to their high lipid contents. Co-HTL using different ratios of mustard and canola meals showed that a 1:3 ratio produced biocrude with the lowest heteroatom content. Optimization of temperature (260–340 °C), reaction time (0–45 min), and solvent-to-biomass ratio (3–9) revealed that biocrude with minimal oxygen content and significant yield was achieved at 320 °C, 30 mins, and a 5:1 water-to-biomass ratio. The physicochemical properties of biocrude and bio residues were evaluated for potential applications.