Production of biocrude oil through hydrothermal liquefaction of palm empty fruit bunch with ethanol co-solvent: A source of value-added chemicals

Palm empty fruit bunches (EFB) is the most abundant biomass from palm oil industries which needs further attention as a source of value-added materials. Hydrothermal liquefaction (HTL) of biomass at subcritical conditions can provide valuable products such as biocrude oil and hydrochar with minimum emission of CO₂. In this work, hydrothermal liquefaction of EFB was investigated at different conditions such as 275 and 300 °C, in presence of organic solvents (ethanol, methanol, isopropanol) with a reaction time of 30 min and an initial pressure of 10 bar. In addition, the presence of an oxidation agent, hydrogen peroxide was also investigated in optimized conditions. GC-MS, FTIR, TGA, and CHNS were used to characterize the properties of the biocrude oil and hydrochar. The highest biocrude oil yield of 40.8 wt% was obtained at 275 °C with 40 vol% ethanol as co-solvent in water. GC-MS analysis indicated that the biocrude oil produced at these conditions was rich in phenolic and enone compounds. Pure ethanol solvent provided the lowest yield for biocrude oil, while the water-ethanol mixture provided a high yield of biocrude oil with different groups of value-added chemicals. Hydrochars were thermally stable until 250 °C and lost around 40 wt% at 900 °C.