Mild Hydrothermal Liquefaction of High Water Content Agricultural Residue for Bio-Crude Oil Production: A Parametric Study

Abstract

Depleting petroleum reserves together with the associated environmental concerns have intensified the exploration of alternatives to petroleum. Wet food processing wastes present promising bioresources for liquid fuel production via hydrothermal liquefaction (HTL) followed by additional upgrading. In this study, tomato plant waste (TPW) was utilized as a feedstock for the production of bio-crude oils via HTL at medium-temperature (220–280 °C) in water or a water–ethanol (17/3, v/v) medium in a 600 mL autoclave reactor. Effects of various operating parameters, such as catalysts (H2SO4 or KOH), reaction time (15–60 min) and reaction temperature (220–280 °C) on product yields were investigated. This study showed that a high yield (45.1 wt%) of bio-crude oil was achieved from HTL of TPW in water–ethanol medium at 250 °C in the presence of acid catalyst H2SO4. The oil, gas and solid residue (SR) products were analyzed for their chemical and structural properties.