Influence of main parameters on wood sawdust gasification in supercritical water

Hydrogen is gaining increasing attention as an encouraging future energy. Thermochemcial gasification of biomass in supercritical water has been identified as a promising approach to producing renewable hydrogen. The raw biomass feedstock of wood sawdust mixed in sodium carboxymethylcellulose (CMC) was gasified at a pressure range from 17.5 MPa to 30 MPa and 650°C in a tubular flow reactor with a reactor residence time of 14.4-50 s. The influence of the main parameters (pressure, temperature, residence time and concentration of solution) on wood sawdust gasification was investigated. Wood sawdust was gasified almost completely. The product gas was composed of hydrogen, carbon dioxide, methane, carbon monoxide and a small amount of ethane and ethylene. The molar fraction of hydrogen in excess of 40% was reached. Results from the experiments showed that recycling liquid effluent was possible.