Cathode–anode side interaction in SOFC hybrid systems

Cathode–anode interaction, mainly based on cathode versus anode volume influence, recirculation performance, and turbomachinery integration, is an important issue for pressurised SOFC hybrid systems, and this aspect must be carefully considered to prevent fuel cell ceramic material failures through a reliable control system. Over the last 10 years, several theoretical analyses of this issue have been carried out at the University of Genoa. These interaction studies have been analysed and an experimental approach (for model validation, system development and prototype design activities) has been applied using emulator facilities or real plants. In particular, general hybrid system layouts based on the coupling of pressurized SOFC stacks of different geometries (planar, tubular, etc.) with a gas turbine bottoming cycle have been investigated using the hybrid system emulator facility of the University of Genoa. The experimental results are focused on the interaction between gas turbine and anodic circuit and on cathode–anode differential pressure behaviour for design, off-design and transient hybrid system operative conditions. The information obtained in these tests is essential to understand the main features of the variables that drive the phenomena and to design a suitable control system that can mitigate the differential pressure values during all plant operating conditions.

► Cathode–anode interaction issues.
► Hybrid system emulator with anodic recirculation.
► Grid-connected and stand-alone tests.
► Cathode–anode differential pressure.
► Control system aspects.