Chemical characterisation of sugarcane bagasse bio-oils from hydrothermal liquefaction: Effect of reaction conditions on products distribution and composition

The effects of temperature, residence time, catalyst use, and recycling on the composition of bio-oil as a result of the hydrothermal liquefaction (HTL) of sugarcane bagasse were investigated via comprehensive two-dimensional gas chromatography with time-of-flight mass spectrometry (GC x GC-TOFMS) and high-resolution mass spectrometry (Orbitrap HRMS) with electmspray ionisation (ESI). HTL bio-oils from sugarcane bagasse contain linear and branched aliphatics, aromatics, phenolic derivatives, carboxylic acids, esters, and other heterocyclic oxygen-containing compounds. The HHV from the HTL bio-oils are between 19.0 and 21.2 MJ/kg, lower than HHV of petroleum fuels. The operational parameters had different influences on the degrees of the decarboxylation and dehydration reactions. The processed water reuse has been shown to benefit deoxygenation and promoted decarboxylation reactions, while the residence time had less influence. The phenolic compounds formation was favoured by the increase in temperature and the use of catalysts, and ketone and furan concentration showed opposite results. Higher temperature and catalyst use also increased the number of detectable polar compounds with high molecular weights.