Performance Comparison of Internal Reforming Against External Reforming in a SOFC, Gas Turbine Hybrid System

Solid Oxide Fuel Cell (SOFC) manufacturers are presently considering both internal and external reforming fuel cell designs. Generally, the endothermic reforming reaction and excess air through the cathode provide the cooling needed to remove waste heat from the fuel cell. Current information suggests that external reforming fuel cells will require a flow rate twice the amount necessary for internal reforming fuel cells. The increased airflow could negatively impact system performance. This paper compares the performance among various external reforming hybrid configurations and an internal reforming hybrid configuration. A system configuration is introduced that uses interstage external reforming. Results show that that the thermodynamic performance of an interstage reforming system is an improvement over a base-concept external approach, and may be slightly better than the hybrid with an internal reforming fuel cell.