LAUSR

Abstract In the present study, three different solvents – ethyl acetate, tetrahydrofuran and petroleum ether – were used to extract bio-crude from a hydrothermal liquefaction product mixture obtained from canola meal and waste wheat flour. The bio-crude yields and the ease of extraction were compared for each of the solvents to evaluate the efficacy of the solvent-extraction process and to determine the most suitable solvent for the same. Among the three solvents, ethyl acetate was identified as the most favourable option for solvent-extraction. The extraction carried out using ethyl acetate yielded significantly large amounts (bio-crude yield: 31.8 wt%) of an easy-to-handle, high quality bio-crude that is most suitable for further upgrading processes and eventual bio-diesel applications. The bio-crude extracted using ethyl acetate had a higher heating value of 46.0 MJ/kg, an oxygen content of 9.2 wt% and an ash content of 0.1 wt%. The aforementioned bio-crude exhibited the highest oxidation stability at room temperature with an induction period of 86.5 days and had a significant percentage of its compounds in the C13-C24 carbon range. The amounts of nitrogen and sulphur were quite low in all the bio-crude samples. Silica polymorphs such as quartz and α-cristobalite, along with calcium mica, were the dominant phases in all the bio-residue samples. The bio-residue obtained using ethyl acetate had the highest specific surface area (249 m2/g) among the three bio-residue samples with an average pore volume of 0.37 cm3/g and an average pore size of 7 nm.