Comparison and analysis of heat exchange and off-gas recycle strategies in tri-reforming-SOFC system

Integrating tri-reforming into SOFC system can convert fuels flexibly and reduce carbon emissions. The tri-reformer-SOFC system requires heat management to reduce energy consumption and to average temperature profiles. In this paper, four system configurations were built with two gas recirculation strategies (anode off gas recycling and burner off-gas recycling) and two reformer types (with heat exchange and oxygen injections). 1-D spatial distributions in the reformer/SOFC and the effect of recirculation ratio (RR) are explored. It is found that the two recirculation strategies can enhance the system electric efficiency due to the recycled fuel and heat, and the two reformers can both average the temperature profiles. Among the four configurations, configuration A exhibits the best performance, and higher RR increases the system electric efficiency, decreases the max temperature gradient in the SOFC and decreases the system global efficiency slightly. This work proposes novel strategies for SOFC system and provides important data for practice.