Production and characterization of biocrude and biochar obtained from non-edible de-oiled seed cakes hydrothermal conversion

•Hydrothermal conversion of three de-oiled seed cake to biofuel is investigated.•Pongammia de-oiled seed cake yields to maximum biocrude.•Pongammia biocrude has the maximum energy content and aliphatics compounds.•GC/MS and GC of biocrudes confirm the presence of heavy hydrocarbons.

Hydrothermal conversion coupled with high pressure water and steam of three de-oiled non-edible seed cakes of Jatropha curcasa, Pongammia pinnata and Tung to biocrude is explored in this work. The cakes were characterized for proximate, ultimate and ligno-cellulosic compositions using ASTM and TAPPI standard methods. All studies were conducted at high temperature and pressure in a semi-batch autoclave. Highest conversion with maximum biocrude yield (∼35.3%) was obtained with P. pinnata cake. Silica adsorption chromatography result showed higher oxygenated aromatics subfraction in both Tung biocrude and Jatropha biocrude. GC/MS qualitative analysis confirmed the presence of heavy, oxygenated/ nitrogenous and poly aromatic hydrocarbons with carbon number ranging from C5-C47 in the biocrude. The viscosity, pH, density, total acidic number (TAN) and water content of biocrudes were evaluated using various standard methods. 34.2 to 45.8% increases in the calorific value is observed for biomass to biocrude. Biochar obtained were characterized using proximate and ultimate analysis and SEM, TGA techniques. Higher calorific values (24.7–26.3 MJ/kg) of all the biochar make them suitable for their potential application as briquettes in the furnace for power generation.