Hydrothermal liquefaction of Litsea cubeba seed to produce bio-oils

Hydrothermal liquefaction (HTL) of Litsea cubeba seed was conducted over different temperature (250–350 °C), time (30–120 min), reactor loading (0.5–4.5 g) and Na2CO3 loading (0–10 wt.%). Temperature was the most influential factor affecting the yields of product fractions. The highest bio-oil yield of 56.9 wt.% was achieved at 290 °C, 60 min, and reactor loading of 2.5 g. The presence of Na2CO3 favored the conversion of the feedstock but suppressed the production of bio-oil. The higher heating values of the bio-oil were estimated at around 40.8 MJ/kg. The bio-oil, which mainly consisted of toluene, 1-methyl-2-(1-methylethyl)-benzene, fatty acids, fatty acid amides, and fatty acid esters, had a smaller total acid number than that of the oil obtained from the direct extraction of the starting material. It also contained nitrogen that was far below the bio-oil produced from the HTL of microalgae, making it more suitable for the subsequent refining.