Optimization of bio-crude yield and its calorific value from hydrothermal liquefaction of bagasse using methanol as co-solvent

Hydrothermal liquefaction is a promising resource recovery technique to valorize wet lignocellulosic agro residues. In this study, hydrothermal liquefaction of bagasse was performed at different temperatures (280, 300, 320 degrees C), reaction times (15, 30, 45 min), and amount of KOH catalyst (5, 7.5, 10 wt%) in the presence of methanol as a co-solvent. The process conditions were optimized using response surface methodology to maximize the yield of bio-crude and its higher heating value (HHV). Maximum biocrude yield of 36.3 wt% was obtained at 320 degrees C, 15 min and 10 wt% KOH. The bio-crude yield was found to depend on temperature, amount of KOH, and the interaction of reaction time and amount of KOH. Maximum HHV of bio-crude (34.6 MJ kg(-1)) was recorded at 320 degrees C, 45 min and 10 wt% KOH, and this condition corresponded to highest deoxygenation achieved in the bio-crude. The major organic constituents in the bio-crude were cyclo-oxygenates, phenolics, and esters, and their combined selectivity was 78-83%. Maximum energy recovery of 56% was obtained. The energy content of the solid residue was high (similar to 23 MJ kg(-1)) at the center point corresponding to 300 degrees C, 30 min and 7.5 wt% KOH. The process exhibited positive energy gain with favorable sustainability metrics. (C) 2022 Elsevier Ltd. All rights reserved.