Design eines hocheffizienten Festoxid-Brennstoffzellensystems mit integrierter Schutzgaserzeugung

  • Design of a highly efficient solid oxide fuel cell system with integrated safety gas generation

Engelbracht, Maximilian Florian Alexander; Stolten, Detlef (Thesis advisor); Wirsum, Manfred Christian (Thesis advisor)

Jülich : Forschungszentrum Jülich GmbH, Zentralbibliothek (2016, 2017)
Book, Dissertation / PhD Thesis

In: Schriften des Forschungszentrums Jülich. Reihe Energie & Umwelt/Energy & Environment 346
Page(s)/Article-Nr.: 190 Seiten : Illustrationen, Diagramme

Dissertation, RWTH Aachen University, 2016


The decision reached at the UN Climate Change Conference in Paris provides to keep global warming temperature increase below 1.5 °C, which should limit the impact of climate change. To achieve this, especially within the energy sector, new low emission and efficient energy conversion systems must be provided. The new systems must have a flexible part load capacity in order to compensate for the fluctuating influence of renewable energy sources on the power grid. Solid oxide fuel cell systems achieve a high partial load flexibility, and at the same time, a high electrical efficiency and thus fulfill today already the requirements for future energy conversion systems.The research objective of this work is an efficiency increase of a solid oxide fuel cell system developed at the Forschungszentrum Jülich, with a particular focus on the development of an innovative safety gas generator for the heating and cooling phases. In particular this means the removal of premixed safety gas compressed in gas cylinders, which currently limits the system’s suitability for everyday use.To achieve these objectives, dynamic component simulation models were developed on the basis of a stirred tank reactor cascade. With these models different system concepts were then investigated to ensure their feasibility and efficiency. Of the chosen criteria, the most suitable concept is a solid oxide fuel cell system with an anode off-gas recirculation, in combination with a low temperature blower. With this concept, electrical efficiency could be increased from 41% to 60%. In order to enable the release of premixed safety gas, a new safety gas release strategy was developed. This includes a component that uses the resources provided by the infrastructure to generate a hydrogen-rich atmosphere within the safety gas requiring operating phases. The functionality of the developed anode off-gas recirculation concept, as well as of the protection gas strategy, has been experimentally demonstrated.Through the combination of dynamic simulation models and experiments, a highly efficient system, consisting of anode off-gas recirculation and own safety gas generation, was achieved. Thereby, the challenges of operating the system could be resolved by developing a recirculation measuring method, an operation strategy to achieve maximum electrical efficiency, an analysis of the carbon-free operation window, as well as an innovative operating strategy within the safety gas requiring operating phases.