Hydrothermal liquefaction of water hyacinth (Eichhornia crassipes): influence of reaction temperature on product yield, carbon and energy recovery, and hydrocarbon species distribution in biocrude

Hydrothermal liquefaction (HTL) of biomass derived from Eichhornia crassipes popularly known as water hyacinth (WH) was performed at different reaction temperatures of 280 °C, 300 °C, 320 °C and 350 °C at a constant reaction time of 30 min using a feedstock with ~ 20% w/w solids in a 1-L HTL batch reactor. This study was aimed at the following: quantification of HTL products, estimation of carbon and energy recovery in biocrude and solid residues and analyses of hydrocarbon species distribution in biocrude. The results showed that biocrude yield increased with an increase in reaction temperature, to a maximum of 37 wt% (43.7 wt% on the basis of dry ash free biomass or daf) at 350 °C with a higher heating value of 23 MJ/kg. Up to 86.9% conversion was achieved and the carbon and energy recovery in the biocrude obtained through HTL of WH biomass at 350 °C was 70% and 78%, respectively. GC-MS analysis of biocrude showed presence of a complex mixture containing hydrocarbons, phenolics, and large amounts of O- and N- compounds. This study showed that aquatic weeds like water hyacinth could be used as potential feedstocks for producing biocrude and/or bio-based renewable chemicals, while simultaneously helping in the bioremediation of water bodies.