Evaluation of steady-state characteristics for solid oxide carbon fuel cell short-stacks

Solid oxide based carbon fuel cells (SO-CFCs) offer clean and efficient utilization of carbon based fuels for energy conversion. In this work, we have realized and operated 100 and 200 W-class solid oxide carbon fuel cell (SO-CFC) short stacks to investigate the fuel supply, electrochemical performance, continuous operation, long-term stability, and scale-up characteristics for SO-CFC based power generation systems. Different configurations for 100 and 200 W class short stacks were employed for integrated Boudouard gasification and carbon fuel supply at the stack level. For the 100 W class SO-CFC short stack, maximum stack power of 80.4, 93.5, and 111.5 W was achieved at 700, 750, and 800 °C, respectively, while the 200 W class SO-CFC short stack produced maximum power of 224.4 W at 750 °C when operated on carbon fuel. Both SO-CFC short stacks were operated continuously at galvanostatic conditions to study the fuel supply conditions and long-term degradation behavior of the tubular cells in the short stacks. A postmortem analysis of the SO-CFC anode was also performed by SEM and XRD to elucidate the reasons for stack performance degradation during relatively longer operation with carbon fuels. Through a detailed analysis of the dry gasification in the integrated gasifier, the electrochemical performance of the SO-CFC stacks, and the post operation diagnosis of the cells, this study provides details on the important challenges in scaling-up SO-CFC technology from a single-cell to a several hundred watt power generation system.