The GALACTICA research environment at the DLR Institute of Technical Thermodynamics in Stuttgart offers the possibility of investigating reactors with several solid oxide cell stacks (SOC). The design of the system allows adaptation to reactors from different manufacturers, variation of the gas compositions and a wide temperature operating range.
The stationary and dynamic behaviour of SOC reactors is being investigated at GALACTICA. These can be operated both in electrolysis mode (SOE) and in fuel cell mode (SOFC), whereby the fuel gases can be varied. Reformer gas compositions of hydrogen, methane, carbon monoxide and carbon dioxide can also be set for SOFC operation. In SOE operation, in contrast to other electrolysis technologies, not only water vapour can be converted to hydrogen, but also gas mixtures of water vapour and carbon dioxide can be converted to synthesis gas (hydrogen and carbon monoxide). Strategies and concepts are derived from the operational investigations that enable safe and low-ageing operation of these SOC reactors. The results also allow conclusions to be drawn about the behaviour in the larger process engineering system context. The real test data from the experiments at GALACTICA provide important parameterisation data for the reactor and system models of the TEMPEST and CELESTE simulation environments.
A recently started expansion of the test environment to include a battery module is to be used to demonstrate a hybrid system consisting of SOFC and battery (maritime drive train). The complex coupling of charging and discharging strategies as well as the development of control strategies for a secure energy supply through such an SOFC battery unit enable application-oriented system research.
Mode of operation
Various operating modes can be analysed:
Fuel cell mode (SOFC) for power generation up to 40 kWel
Electrolysis mode (SOE) for the production of hydrogen or synthesis gas from hydrogen and carbon monoxide using electrical energy of up to 120 kWel
Reversible operation (rSOC) e.g. for the intermediate storage of electrical energy in the form of chemical energy, switching between SOFC and SOEC operation
Media supply & disposal
On the fuel gas side, H2, CO2, CO, N2 and CH4 as well as H2O(g) (up to 28 kg/h) are available. Two air compressors regulate the air flow up to 360 m3/h. Two electric heaters with a total output of 156 kW each ensure that the process gas and air flow are heated to operating temperatures of up to 850 °C in the SOC reactor.
GALACTICA experimental environment
NAUTILUS experiments with SOFC-Battery hybrid genset have been performed in the GALACTICA test facility at DLR. GALACTICA provides SOC system testing capabilities in fuel cell-mode (up to 40 kWe) and electrolysis-mode (up to 120 kWe)
In-situ characterisation methods such as online gas analysis of product gases and electrochemical impedance spectroscopy (EIS) provide a detailed view of system performance as well as identification and quantification of cell and reactor resistances at reactor level.
