Reporting Degradation from Different Fuel Contaminants in Ni-anode SOFCs

The real-life operation of solid oxide fuel cell (SOFC) system has to deal with fuel contaminants which might reduce even significantly the lifetime of reformer and stack depending on the type and amount of contaminant present in the feed stream. From a system perspective, detecting and correlating observed stack and reformer performance degradation with fuel contamination is fundamental to implement correctional procedures (e.g., change of clean-up vessels catalysts) and/or trigger alarms to prevent a further contamination of the fuel cell. In this work, based on own experiments with several fuel contaminants (H2S, HCl, tars, siloxanes), we have developed empirical degradation models which are able to quantitatively correlate the range of degradation rate resulting from known amounts of a certain contaminant type in the fuel stream. Degradation induced by carbon deposition is also assessed using a simulation model. The techno-economic trade-off of having ultra-stringent purification requirements on the fuel clean-up unit due to additional operating costs (e.g., for frequent catalysts change) or capital costs (e.g., for vessel over-sizing to accommodate a larger amount of catalysts and possibly of different types) versus the lifetime of the fuel cell stacks is eventually analyzed.