Solid Oxide Fuel Cell short stack performance testing - part B: Operation in carbon capture applications and degradation issues

The need to experimentally understand the performance of Solid Oxide Fuel Cells (SOFC) stacks under Carbon Capture and Storage (CCS) mode operating conditions, hence with anode recirculation, has prompted this two-part study. The steady state performance of a 6-cell short stack of Y2O3 stabilised Zirconia (YSZ) with Ni/YSZ anodes and composite Sr-doped LaMnO3 (LSM)/YSZ cathodes is experimentally evaluated. In Part A, the electrical and environmental performance are assessed and the results are compared with the commercial full-scale micro-Combined Heat and Power system, which comprises the same cells. In Part B of this work, a specific set of stack operating conditions important to CCS applications is explored. The experimental inlet composition is changed in order to reproduce a simulated syngas in CCS mode operation for different fuel utilisation factors. Operation with the simulated anode recycle syngas leads to lower voltage when the anode recycle is lower, mainly due to higher internal reforming and polarisation losses. A clear voltage trend is observed when the amount of CO content in the inlet fuel is increased, signalling an improvement of the polarisation performance at constant current density and fixed inlet equivalent hydrogen content. Stack degradation is measured and results in line with manufacturer's data.