Effect of process parameters on hydrothermal liquefaction of waste furniture sawdust for bio-oil production

Abstract

In the present study, hydrothermal liquefaction of waste furniture sawdust was examined. The effects of various reaction conditions such as reaction temperature (180–300 °C), residence time (0–60 min), water to sawdust ratio (2–10) and initial N₂ pressure (0–2 MPa) on the product yields were studied using a high pressure batch reactor in order to determine the optimal liquefaction parameters for the production of maximum bio-oil yield. The solid residue was characterized to investigate the mechanism of hydrothermal liquefaction process by FT-IR. The highest sawdust conversion (61.6 wt%) and bio-oil yield (12.7 wt%) were obtained at 280 °C, 15 min and ratio of the water to sawdust of 6 with initial N₂ pressure of 1.0 MPa. The higher heating values (HHVs) of the bio-oils were found to be within the range of 17–30 MJ kg⁻¹. The GC-MS analysis revealed that sawdust liquefaction bio-oils comprised a complex mixture of organic compounds, which include alcohols, acids, aldehydes, ketones, esters, phenols and their derivatives.