Durability of direct-internally reformed simulated coke oven gas in an anode-supported planar solid oxide fuel cell based on double-sided cathodes

A simulated coke oven gas (COG) is used as internally-reformed (IR) fuel in an anode of solid oxide fuel cell based on double-sided cathodes (DSC-SOFC) and the durability of the cell is studied. The DSC-SOFC operates stably for over 240 h when the steam to methane (H2O/CH4) ratio is above 3 with performance degradation of about 0.01% per hour, but it has a larger degradation of about 0.08% per hour when the H2O/CH4 ratio is lower than 2.5. The mechanism of the cell degradation has been analyzed in detail. It is found that the H2O/CH4 ratio approximately equal to 1 is the key point affecting cell performance. The results of cell analysis by energy dispersive spectroscopy and Raman spectroscopy indicate that carbon deposition mainly takes place at the inlet and at the middle of DSC-SOFC. Due to thick anode substrate in this type of cell, carbon distribution on the cross-section reveals that there are two carbon producing areas, one close to the anode surface, and the other near the three-phase boundary. Some of the deposited carbon can be carried by the fuel gas to exhaust which lowers the actual carbon amount in the cell, thus prolonging the cell operation.