Development of Highly-Efficient SOFC System Using Anode Off-gas Regeneration Technique

To improve the power generation efficiency of a solid oxide fuel cell (SOFC) system, we tried to operate the system at extremely high fuel utilization around 90% while keeping lower fuel utilization for individual cell-stacks. We designed the system with two-stage SOFC stacks and a fuel regeneration process. The system was operated at a high total fuel utilization rate of 88.4%, and the gross power generation efficiency reached DC 71.2% at its lower heating value and gross power output of 2 kW. In addition, our system was operated for more than 500 hours without degradation. The technologies of the two-stage SOFC stacks and fuel regeneration process were proven to make stable power generation possible even with high fuel utilization in the system.