Demonstration of a Highly Efficient SOFC System with Combined Partial Oxidation and Steam Reforming

Abstract

SOFC (solid oxide fuel cell) are known for a high electrical efficiency and especially the ESC (electrolyte supported cells) for a good robustness for system operation. Nevertheless common system concepts that use CPOX (catalytic partial oxidation) or SR (steam reforming) as fuel processing still show disadvantages. CPOX systems will not pass efficiencies beyond 35% and SR systems need additional water processing that increases complexity, as well as initial and operational costs. A technical solution for those disadvantages is a staged system design. staxera GmbH has developed a concept and EBZ GmbH has designed, built and operated a proof-of-concept installation including a serial connection of two SOFC stacks. This system design achieved an electrical efficiency of 55% due to a double use of fuel gas in stage two. In contrast to other highly efficient SOFC systems, mostly SR systems, no additional water supply and processing were needed.