Catalytic Hydrothermal Liquefaction of Waste Furniture Sawdust to Bio-oil

Abstract

The objective of present study is to investigate the effect of alkalis (NaOH, Na₂CO₃, KOH and K₂CO₃) on hydrothermal liquefaction of waste furniture sawdust (mixture of different types of waste woods) under sub-critical water conditions in a batch reactor operating at 280°C for 15 min. The liquefaction products were analysed using Fourier transform infrared spectroscopy, elemental composition, higher heating value and gas chromatography-mass spectrometry (GC-MS). The highest total bio-oil yield (34.9 wt%) and lowest solid residue yield (6.8 wt%) was obtained in the presence of 1.0 M K₂CO₃. Reactivity order for alkalis based on biomass conversion and liquid yield was found to be K₂CO₃ > KOH > Na₂CO₃ > NaOH. The experimental results showed that the bio-oils produced were enriched in carbon and hydrogen and had reduced level of oxygen compared with original sawdust. The GC-MS analysis showed that light bio-oils and heavy bio-oils comprised a complex mixture of organic compounds, which mainly include phenols and their derivatives.

Keywords:

• Hydrothermal liquefaction
• Sawdust
• Bio-oil
• Alkalis
• Solid residue

Disclosure statement

No potential conflict of interest was reported by the authors.