Numerical Simulation of SOFC System Performance at 90% Fuel Utilization with or without Anode Off-Gas Recycle for Enhancing Efficiency

Monday, 27 July 2015
Hall 2 (Scottish Exhibition and Conference Centre)
Y. Tanaka, T. Terayama, A. Momma, and T. Kato (National Institute of Advanced Industrial Sci. Technol.)
To investigate possibility to enhance electrical efficiency, performance of methane-fueled 10 kW SOFC systems was numerically simulated with calculated voltage-current-density curves at 750ºC of a single cell with a bipolar plate, which approximated a stack performance. Operation at 90% fuel utilization (Uf) with anode off-gas recycle (AGR) and with steam reforming (no recycle) led to 75-67%-LHV and 72-66%-LHV DC electrical efficiency at 0.05-0.40 A/cm2, respectively. System simulations considering heat loss from a cell stack clarified that 750ºC stack temperature can be maintained at 0.12-0.40 A/cm2 and 64-58% and 63-59% net AC electrical efficiency will be attainable at Uf = 90% with and without AGR, respectively. Furthermore, enhancement of net AC efficiencies was found to be 11-10 percentage points at those current densities against ones of a Ene-farm-like conventional system using steam reforming at Uf = 73%.