Energetic and economic analysis of novel cascade systems for ammonia-fed solid oxide fuel cell

Abstract

This study proposes an ammonia-fed cascade recirculation system comprising: (1) two stacks connected in series and (2) an anode off-gas recirculation configuration to enhance electrical efficiency of the system. The proposed system is both energetically and economically investigated. Under energetic analysis, the effects of fuel utilization, temperature, and recirculation rate, are clarified. Information from energetic analysis is employed to investigate levelized cost of electricity (LCOE) value in the entire working range. Due to the high potential of the cascade configuration, a cascade system without recirculation is also investigated using the same methods. The results reveal that the cascade-only and cascade recirculation systems obtain electrical efficiency up to 67.78% and 68.80%, respectively. The minimum LCOEs are 0.485 and 0.486 $/kWh, respectively, which are both higher than grid electricity cost; however, compared with other ammonia-fed SOFC systems, the two cascade configuration-based systems show significant improvements in both efficiency and cost.