Design and Evaluation of a Metal-Supported Solid Oxide Fuel Cell Vehicle Power System with Bioethanol Onboard Reforming

Abstract

A solid oxide fuel cell (SOFC) has wide stationary and mobile application prospects due to its high efficiency and fuel flexibility. The SOFC system's performance depends on the reforming option and system design. In this paper, we designed a novel SOFC auxiliary power unit (APU) system with ethanol on-board reforming aiming at vehicle application. The thermodynamic analysis is employed to evaluate the ethanol-fueled SOFC performance of different reforming options with a metal-supported SOFC working at 600 °C and a 0.3 A/cm2 current density. The electrical efficiency of the SOFC can reach a maximum of 50% with ethanol autothermal reforming. Under the optimal reforming option and operating conditions, the conceptual SOFC-APU system design is identified with the trade-off between system efficiency and ethanol flow from the startup and stable operation phase. The results show that the system efficiency of 44.4% can be achieved with a 0.42 g/s ethanol flow at the startup phase. During the stable operation, the electrical efficiency and exergy efficiency of the SOFC-APU system can reach 55.4 and 77.1% with a 70% anode gas recirculation ratio, respectively.