(641c) Effect of Operating Temperature and Voltage On a SOFC Anode Fueled by Phosphorus Contaminated Coal Syngas

Among different types of fuel cells, solid oxide fuel cells (SOFCs) have the advantage of fuel flexibility where it can operate on fuels such as coal syngas and natural gas in addition to pure hydrogen. With the identification of potential to improve energy efficiency by employing an integrated gasification fuel cell (IGFC) system, research on trace contaminants in syngas that can deactivate SOFC Ni/YSZ anodes has gained significant attention. Thermodynamic analysis based on experimental data obtained from various gasifiers have revealed that phosphine (PH3) a phosphorus based gaseous contaminant can exist in concentrations in the region of 1.9 ppm in coal syngas. Such a fuel can be detrimental to electrochemical reactions occurring in a SOFC anode as nickel phosphides are formed. However the oxygen partial pressures at the anode that operates in a reducing atmosphere can be varied by current generated in the fuel cell. In addition phosphorus can react with available oxygen and form gaseous oxides. This research concentrates on varying oxygen partial pressures via changing operational voltage and monitoring electrochemical performance of the SOFC at temperatures above 800°C. Material tests such as SEM, EDXS, XRD and XPS will be performed on the SOFC anode following electrical tests, in order to investigate new phase formation and changes to surface morphology