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.

Despite long and successful development history of Solid Oxide Cells (SOC) continuous improvement in performance, longevity, manufacturing and system integration is necessary to bring this highly efficient technology to the market. The activities on material development and optimization at IKTS are focused mainly on enhancement of durability in SOFC, SOEC and rSOC operation and on boosting the power density for electrolysis operation. The recent results show considerable enhancement in cell longevity and power density. The SOC priorities in applied research are moving from materials to industrialization and Fraunhofer as applied R&D service provider is following this trend. During recent years considerable efforts on simplification and automation of cell and stack manufacturing processes has been addressed at IKTS. The manufacturing processes for electrode manufacturing have been adjusted for high yield automated printing on thin electrolytes with integrated quality control measures. The efficient ways for reduction of time and energy consumption for sealing process of SOC stacks have been found and shown in pilot production as well as automated assembling of components to stacks demonstrated. Furthermore the stack integration into modules utilizing stacks of different providers has been addressed during last years and reliable solutions for building of compact stack modules of higher power (2 to 10 kW) has been developed and tested with industrial partners. The increasing interest in “green hydrogen” generated multiple opportunities for SOEC technology to be considered as inherent part of industrial and chemical processes. IKTS pioneering work on coupled operation of SOEC module with Fischer-Tropsch reactor provided first demonstration of feasibility of this approach for waxes production. The process design and analysis of steel, using SOEC technology, has been performed and resulted in multiple demonstration activities in last four years. Recently novel approaches for ammonia production are addressed at IKTS showing opportunity for transportable chemicals/fuel production without need of CO2 source. High power electrolysis applications (>10 MW) will need new approaches for stack design and put higher requirements on durability. High power electrolysis applications will also open a new window of opportunities for industrial SOFC power plants. This vision is considered as outline for our future research.