A stationary SOFC system utilizing gas from a biomass updraft gasifier is under development within the project “HiEffBioPower” by MAWERA, BIOS, Bosal, AVL, Calida Cleantech, Fraunhofer IKTS, Wuppertal Institute and University Utrecht (European Union Horizon2020 No. 727330). The system is based on Mk352-CFY-stack with Chromium based (CFY) interconnects and electrolyte supported cells. These stacks are robust, redox stable and demonstrated low degradation rates. The stacks are arranged to modules of eight 30-cell stacks and are electrically connected in series. The stack module was pre-tested at the test rig at IKTS and showed performance in accordance with system requirements. Stationary power points were measured to compare the behaviour of the stack module with the system tests at MAWERA. AVL designed and installed the overall SOFC system (heat exchangers, stack, catalytic afterburner, process control and visualisation) with a nominal capacity of 6 kWel. After shipping all parts of the SOFC system to MAWERA in Hard (AT), the coupling of the biomass gasifier, the gas cleaning unit and the SOFC system was conducted. The system is operated by an automated process control. The highest efforts needed the novel gas cleaning unit, consisting of a high temperature filter, a desulphurisation unit as well as a novel catalytic gas reforming stage developed by BIOS. The biomass gasifier has been operated with wood chips of different quality. The high tar contents of the product gas make a tar cracking essential to reach a high calorific value of the gas for the SOFC system. The novel gas cleaning system shows good performance and reaches the defined SOFC requirements. The SOFC system developed and operated by AVL reached stable conditions for several days. The operating results of the stack module at lab conditions and at the real system are in a good agreement. The SOFC stack module performance in terms of cell voltages, stack temperature distribution and fuel utilization under biomass reformate fuel will be shown and supported by several simulation to get an overall energy balance. Examples of optimization for several components by CFD simulation and component tests will be given.

The coupling of AVLs 6 kW EL SOFC CHP system using an IKTS stack module with a 5 kW COLD absorption heat pump developed by TU Graz will be presented. The exhaust gas heat from the SOFC which is available at >200°C will be used to operate the thermally driven heat pump. The SOFCs fuel capability was extended towards renewable fuels such as biogas, and synthetic diesel using a novel gas cleaning concept. For buildings, a heat driven operation mode leads to low operating hours per year for conventional CHP systems during summer season. Generating cooling power in addition to heat will increase the annual operating hours per year and thus economic efficiency significantly. This analysis presents the capability of the SOFC CCHP system for a flexible and demand-oriented generation of electricity, heat and cooling power and shows how cold and cooling water temperatures influence the overall system size.

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This paper will show the results of operating an SOFC system with the product gas from a biomass gasifier for more than 200 hours under constant and dynamic operation. The SOFC system was operated at different load cases, 50 % and 100 % load, and achieved a gross electrical efficiency of 42 %. It shows a high dynamic behavior, so that electric load changes could be performed within a few seconds from full load to part load. Furthermore, AVL developed a simulation software by which a SOFC stack model can be simulated dynamically. A comparison of the measured and simulated values of the stack module will be presented. By using the results of the test runs the software could be validated successfully.