Catalytic Hydrothermal Liquefaction of Waste Furniture Sawdust to Bio-oil

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 degrees 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 biooil 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.