Supercritical water gasification of fruit pulp for hydrogen production: Effect of reaction parameters

Supercritical water gasification (SCWG) is a promising technology for converting high moisture biomass into valuable gas products. In this study, SCWG of fruit pulp was carried out in a batch reactor in the presence of KOH catalyst. The effect of reaction parameters such as temperature (400–600 °C), reaction time (30–180 min), biomass ratio (2.5–10%, wt. biomass/wt. water) and KOH ratio (0–30%, wt. catalyst/wt. biomass) were investigated in order to determine the suitable reaction conditions for maximizing H2 yield. The maximum H2 yield (32.1 mol/kg biomass) was achieved at 600 °C, 30 min, 2.5% biomass ratio and 10% KOH loading. The experimental results indicated that KOH could promote biomass decomposition and increase the amount of gas products via the water-gas shift reaction (WGSR) by intermediate formation of salts and suppressing the char and tar formation. KOH also played a sufficient role in capturing CO2 at high temperatures, proceeding the WGSR equilibrium reaction towards the products resulting in the production of more hydrogen. [Display omitted] •SCWG of fruit pulp was performed in a batch reactor in the presence KOH.•Suitable reaction parameters were investigated to maximize the hydrogen yield.•KOH could promote biomass decomposition by increasing the gas products yield.•The maximum H2 yield of 32.1 mol/kg fruit pulp was achieved at 600 °C, 30 min, 2.5% biomass ratio and 10% KOH ratio.•Supercritical water gasification of fruit pulp has high potential for H2 production.