Hydrogen production by raw biomass gasification in supercritical water with a fluidization bed system

A fluidization bed reactor is proposed for supercritical water gasification of biomass, and for reducing reactor plugging. The mixture of corn cobs and sodium carboxymethylcellulose is gasified for hydrogen production in the new supercritical water fluidization bed system with temperature range 550-650°C and pressure of 25 MPa. The influences of the main parameters such as gasification time, temperature, flow rate, and feedstock concentration on the gasification process are studied. The results from experiments show that the temperature has a significant effect on gasification, and higher temperature is in favor of gasification. Smaller flow rate, which means longer reactor residence time, favors to hydrogen production. Gasification performance of the feedstock is rapidly decreased as increasing the concentration. Biomass feedstock of 18% in concentration is gasified stably during long-term operation and the reactor plugging is not observed.