Catalytic hydrothermal liquefaction of water hyacinth.

Abstract Thermal and catalytic hydrothermal liquefaction of water hyacinth was performed at temperatures from 250 to 300 °C under various water hyacinth:H 2 O ratio of 1:3, 1:6 and 1:12. Reactions were also carried out under various residence times (15–60 min) as well as catalytic conditions (KOH and K 2 CO 3 ). The use of alkaline catalysts significantly increased the bio-oil yield. Maximum bio-oil yield (23 wt%) comprising of bio-oil1 and bio-oil2 as well as conversion (89%) were observed with 1 N KOH solution. 1 H NMR and 13 C NMR data showed that both bio-oil1 and bio-oil2 have high aliphatic carbon content. FTIR of bio-residue indicated that the usage of alkaline catalyst resulted in bio-residue samples with lesser oxygen functionality indicating that catalyst has a marked effect on nature of the bio-residue and helps to decompose biomass to a greater extent compared to thermal case.