Evaluation of Anaerobically Digested Biomass in Catalytic Supercritical Water Gasification for Biofuel Production

Digested water hyacinth with activated sludge as inoculum were obtained after anaerobic digestion at 35 and 45 ° C. High organic content of digested biomass were evaluated through gasification at supercritical conditions of water in the absence and presence of catalysts (KOH, NaOH, LiOH and K 2 CO 3 ) with 10 wt.% of volatile solid in feed. Supercritical water gasification of digested biomass was performed in batch reactor system at temperature and pressure ranges of 500 – 600 ° C and 350 –450 bar, respectively. The highest carbon gasification efficiency, hydrogen and methane yields were reached at 600 ° C (with samples digested at 45 ° C ) in the absence of catalyst as 84.6 ( g C in gaseous/g C in digestate) , 53.0 (mol H 2 %) and 12.5 (mol CH 4 %), respectively. High organic content of digested biomass was converted by supercritical water gasification to hydrogen and methane rich gas, and aqueous products (aliphatic hydrocarbons, phenol, substituted phenols, N-heterocyclic, substituted N-heterocyclics, and substituted benzene) that can be evaluated as platform chemicals.