Influence of Process Conditions on Hydrothermal Liquefaction of Eucalyptus Biomass for Biocrude Production and Investigation of the Inorganics Distribution.

In the present study, eucalyptus biomass was processed to produce biocrude via hydrothermal liquefaction. The effect of process conditions (temperature, alkali catalyst) was initially investigated. The maximum biocrude yield (35.78%, daf) was achieved at subcritical conditions (350 ̊C-catalyst) and comparatively lower at supercritical conditions. The effect of retention time on product yield, organic compounds composition, and distribution of inorganic elements was explored. HTL experiments were conducted at different retention times (5, 10, 15, 20, 25 min) by following the optimum condition (350 ̊C- catalyst) according to this study, to analyze the process efficiency. Results show clear trends of changing the content of different functional groups with a change in retention time. Overall, the majority of the inorganic and heavy metal contents migrated to solid-phase that was conformed from the ICP results. It was concluded from this study, that catalytic-subcritical liquefaction at 15 min retention time is a favorable condition for biofuel production and nutrients recovery.