Comparative investigation on hydrothermal and alkali catalytic liquefaction of bagasse: Process efficiency and product properties

Abstract

In this study, we propose a novel and efficient process for bagasse liquefaction in subcritical water over the solid alkali catalyst of MgMOx (M=Mn, Ni, Fe, Cr, Zn and Al). The intensification effect of the catalyst was investigated via hydrothermal liquefaction, where the product distribution and composition of volatiles and residue were compared using GC–MS, GPC, FT-IR and elemental analysis. The results show that the materials substantially promote bagasse liquefaction. Under optimized conditions (250°C for 15min), MgMnO2 liquefied 93.7% of the bagasse yielding a water-soluble fraction of 59.5%. Of particular note, lignin, the most recalcitrant fragment in biomass hydrothermal liquefaction, is efficiently depolymerized to volatile phenolic monomers with these catalysts. Furthermore, the MgMnO2 catalyst shows good recyclability, where no significant activity loss is demonstrated even after the fifth run.