Effects of regulating the cathode gas properties on the ammonia-fueled solid oxide fuel cell. Part I. Parasitic power consumption and electrical efficiency after increasing O2 and H2O

• Published in: International journal of hydrogen energy 2024-11, Vol.89, p.90-104
• Main Authors: Sun, Boyu, Xu, Yishu, Liu, Yimin, Ya, Yuchen, Liu, Junjia, Xiang, Mingyuan, Zhang, Jie, Hua, Shiyang, Cheng, Xiaobei
• Format: Article
• Language: English
• Subjects: Ammonia; Efficiency; Parasitic power consumption; Solid oxide fuel cell; Stack cooling optimization
• ISSN: 0360-3199
• DOI: 10.1016/j.ijhydene.2024.09.307

This study designed and simulated a kW-scale SOFC system equipped with liquified O2 and NH3 tanks for unmanned underwater vehicles (UUVs). Optimizing the parasitic power consumption and electrical efficiency was performed via using oxygen-enriched cathode gas, in-cell cracking of ammonia and adding steam into cathode gas coupled with phase change of recycle steam. The results show increasing O2 concentration helps improve the net system electrical efficiency from 47.9% at simulate air to 51.7% at pure O2. The use of in-cell cracking increases the net system electrical efficiency by 1.3% on this basis. Interestingly, substitution of O2 to H2O would slightly reduce the net electrical efficiency of the system with O2-enriched cathode gas (e.g., decreased by 0.2% when using 40% H2O); however, substitution of N2 to H2O would help improve the net electrical efficiency of the system with simulated air as cathode gas (e.g., increased by 1.2% when using 40% H2O). [Display omitted] •1D ammonia-fueled SOFC stack model for UUVs are developed.•Optimize performance from the perspective of reducing parasitic power consumption.•An optimization strategy using the phase change process of recycle H2O is proposed.•Energy flow diagrams of the system under different strategy are presented.