Hydrogen production by gasification of high concentration coal in supercritical water

The problems in hydrogen production from coal gasification in supercritical water include low concentration of coal feedstock, discontinuous hydrogen production due to utilizing autoclave, and so on. Our work focuses on hydrogen production by gasification of high concentration coal in supercritical water. An experiment was carried out in a continuous-flow reactor system, where coal is gasified under the conditions of temperature at 650-800°C, pressure at 23-27 MPa and flow rate from 3 to 7 kg/h. The effects of main parameters (temperature, pressure, flow rate, catalyst, oxidant, concentration of coal) were investigated. Mass fraction 16% of coal was successfully transported into the reactor and steadily gasified, hence its gasification efficiency and hydrogen yield rate reached to 0.317 and 0.022, respectively.