The effect of biochemical composition on the renewable crude oil produced from hydrothermal liquefaction of biosolids

The accumulation of biosolids has caused significant harmful pollutants and negatively impacted nearby ecosystems and communities, which requires immediate management and regulation. Biosolids are potentially a highly productive source of renewable crude. Hydrothermal liquefaction is a promising technique to convert biosolids into renewable crude oil. However, challenges exist with optimising the HTL of biosolids, such as identifying biosolids composition and the resultant effect on the produced renewable crude. This work aims to develop and modify methods to analyse biosolids' composition and quantify the effect of biosolids' composition and specific reaction conditions on product distributions derived from HTL. Biosolids with varying compositions were processed using HTL in a batch reactor under controlled operating conditions. The analysis of the biosolids' composition showed that few biosolids samples are close to the composition of biomass content when compared using the Van Krevelen diagram. The results also show that those biosolids with higher lipid and protein content exhibit an increase in the renewable crude yield with a larger content of low-boiling point components. However, biosolids with higher carbohydrate and insoluble lignin content produce lower renewable crude oil yield with a higher content of high-boiling point components and an increased mass fraction of solid residue.