Characteristics of solid oxide fuel cells in gasified gases from biomass

Abstract

For an extremely efficient power generation using biomass, a renewable energy, we investigated characteristics of an autothermal downdraft gasifier and SOFCs. Cypress chips were converted into gasified gases with the efficiency of 90%. The gasification rate saturated as the air flow rate increased, because of the heat losses from char surfaces via radiation and convection. For the discharge of SOFCs, electrochemical H2 oxidation was more dominant than CO oxidation in a model gasified gas, due to water gas shift reaction and selective electrochemical H2 oxidation via H-spillover. Electrochemical H2O reduction was inhibited by strongly adsorbed CO on Ni in the model gasified gas with the reverse bias operation. The maximum polarization resistances of an anode-supported cell were more than two times larger than the charge transfer resistances in the model gasified gas. The power density in the model gasified gas attained 62% of that in humidified H2 at 0.8 V.