Experimental Setup of a Pressurized Solid Oxide Fuel Cell System for Hybrid Power Plants

Kurzfassung

The future energy system will favour electricity generating devices with highest efficiencies, good part load performance and fuel flexibility to consume as little chemical energy as possible. One promising concept to realize that is the combination of solid oxide fuel cells (SOFC) with a gas turbine (GT) in a hybrid power plant. By that the high efficiency and good part load performance of the fuel cell is used while remaining chemical energy in the off-gas of the fuel cell is converted in the gas turbine. Via an integrated steam reformer carbon based fuels can be used. Exhaust heat is recuperated. Recently, Mitsubishi-Hitachi Power Systems demonstrated a hybrid power plant with an electrical power output of 250 kW that runs on natural gas. It is being tested in field trials in Japan and a scale-up to 1 MW is in progress. However, since experimental data for such SOFC/GT systems are scarce the DLR is building a demonstrator with 30 kW electrical output. In the first step two separate test rigs were build. One uses a real GT and components that emulate the SOFC. This MGT system was setup by the Institute of Combustion Technology. The other one uses a 30 kW SOFC under pressurized conditions with components that emulate the GT. This SOFC system was built by the Institute of Engineering Thermodynamics and includes a hot anode off-gas recirculation, a steam reformer and recuperator. State of the art components and commercially available stacks with electrolyte supported cells (ESC) are used. Both systems were put into operation and are now being used to experimentally analyse their operational behaviour. After all necessary investigations it is planned to merge the SOFC with the GT and thereby build a real coupled SOFC/GT system. This presentation will give an overview of the underlying hybrid power plant process, the implementation within the currently installed SOFC system and its first experimental results. The basic design choices, key challenges during the development and necessary modifications will be shown. The experimental results, such as efficiency, power output, part load performance and control strategies will give an insight about the current status of the project.