Improvement of Electrical Efficiency of Solid Oxide Fuel Cells by Anode Gas Recycle

Abstract

Anode gas recycle (AGR) is one of the methods to enhance fuel utilization. In this paper, electrochemical performance of a single planar solid oxide fuel cell (SOFC) was investigated with/without AGR. Cell performance at AGR was successfully evaluated by our simulated-reformate generator without carrying out AGR actually. It was clarified that cell voltage more than 0.8 V could be obtained with AGR at utilization of 90% methane fuel and 45% air, 700ºC and 400 mA cm-2. The cell voltage was by 20 mV higher than one without AGR at the same utilizations. DC electrical efficiency more than 69%-LHV can be expected at AGR-SOFC which is by 2 percent points higher than one without AGR. Furthermore, it was found that deviation of cell voltage against change in current at a constant flow-rate and time constant for gas conversion in anode would be twice smaller with AGR than without AGR.