Comparison of a fuel-driven and steam-driven ejector in solid oxide fuel cell systems with anode off-gas recirculation: Part-load behavior

• Published in: Journal of power sources Vol. 277; pp. 251 - 260
• Main Authors: Engelbracht, Maximilian, Peters, Roland, Blum, Ludger, Stolten, Detlef
• Format: Journal Article
• Language: English
• Published: Elsevier B.V 01.03.2015
• Subjects: Anode recycling; Anodes; Capacitors; Carbon; Condensing; Formations; Fuel cells; Fuel ejector; Part load; Power sources; Simulation; SOFC; Solid oxide fuel cells; Steam ejector; Utilization; Part load; Steam ejector; Anode recycling; Fuel cells; Fuel ejector; SOFC
• ISSN: 0378-7753; 1873-2755
• DOI: 10.1016/j.jpowsour.2014.12.009

This paper investigates the use of ejectors for recirculating anode off-gas in an SOFC system, focusing on the part-load capability of two different systems. In the first system, recirculation was enabled by a fuel-driven ejector. The part-load threshold of this system was determined by carbon formation and was 77.8% assuming a fuel utilization of 70% and suitable ejector geometry. The second system was based on a steam-driven ejector. The simulation results for this system showed an improved part-load capability of 37.8% as well as a slightly improved electrical efficiency. Here, the minimal part load was determined by the condensation temperature of the condenser used in the system. •We model an SOFC system with anode off-gas recirculation.•A steam and fuel driven ejector are used for recirculation.•Carbon formation limits the part load of a fuel driven ejector system.•The condensation temperature limits the part load of a steam driven ejector system.•A steam driven concept increases the electrical efficiency.