Experimental Investigation of�Anode/Cathode Differential Pressures �for a SOFC/Gas Turbine Hybrid Power Plant

Abstract

Providing electrical energy with a reduced CO2 footprint and in a sustainable way is a significant challenge for the future. Therefore the research community is intensively studying more effective ways to provide electricity to consumers. In this respect a hybrid power plant, a combination of SOFC and gas turbine, is highly attractive and a research prototype is being developed at the German Aerospace Center.

The hybrid power plant consists of a pressurized solid oxide fuel cell (SOFC) and a small gas turbine. It has the possibility to provide electrical energy with high electrical efficiencies. In the hybrid power plant the SOFC will be operated at elevated pressure which enhances the electrical power output of the SOFC. The increased SOFC cathode pressure is maintained by the gas turbine compressor. Pressure differences between the two electrode volumes lead to mechanical stresses and may lead to failure of the SOFC.

The durability of the SOFC stack related to pressure differences between anode and cathode compartment was investigated with a planar two layer SOFC stack at operating temperature of 850 °C. The tests were carried out with stationary pressure changes to determine operational limits and potential reasons for failure. The testing procedure and the results will be explained and discussed.