Influence of main parameters on hydrogen production during biomass/coal gasification in supercritical water

Crboxymethylcellulose (CMC)/Huating bituminous coal was considered to be an example of biomass/coal, and the effects of the reaction temperature (350-700°C), pressure (20-35 MPa) and concentration of solution (1.1%-2.0%) on gaseous products during CMC/coal co-gasification in supercritical water were investigated. The simulation results and experimental data show that the main gaseous products are H₂, CO₂ and CH₄. Moreover, hydrogen mole fraction increases with the reaction temperature but it is constant (67%) at a high temperature. Hydrogen mole fraction decreases with the concentration, and temperature and concentration have larger effects on gaseous products than pressure. In addition the reasonable parameters for hydrogen production during CMC/coal co-gasification in supercritical water are 450-550°C, 25 MPa, and the solution concentration ≥15%. It is suggested that heating rate of feedstock in the reactor should be increased and Ni catalyst with good effects at low temperature should be studied in the future experiment.