烃类燃料的直接使用造成固体氧化物燃料电池(SOFC)阳极积碳并导致性能下降的严峻问题,开展积碳原因分析并采取减少积碳形成的措施是加快固体氧化物燃料电池商业化的重要课题。提出三维瞬态多物理场耦合积碳模型,通过仿真模型计算,研究不同条件、不同参数对固体氧化物燃料电池性能的影响,以评估电池的长期性能。在电池工作电压和积碳速率方面,计算结果与已有试验结果吻合较好。结果表明,随着积碳含量增加,阳极电极材料的孔隙率将减小,催化剂活性降低。当预重整程度降低、入口速度增加、操作温度增加、工作电压下降和燃料中氢气比例增大,积碳量均呈上升趋势。通常来说,积碳的增加会造成电池性能下降,如预重整程度的降低及入口速度的增加符合这一趋势。操作温度增加、工作电压下降和燃料中氢气比例增加虽然也会造成积碳量增加、电性能衰减严重,但电池性能呈上升趋势。研究表明,这一现象与甲烷裂解反应关系密切。

The direct utilization of hydrocarbon fuel leads to the significant issue of carbon deposition and performance deterioration in solidoxide fuel cells (SOFC). It is imperative to expedite the commercialization of solid oxide fuel cells by analyzing the causes of carbon deposition and implementing measures to mitigate it. This paper presented a three-dimensional transient multi-physics coupled model for carbon deposition. The impact of various conditions and parametered on the performance of solid oxide fuel cells was investigated through simulation model calculations, aiming to assess the long-term performance of the cells. The calculated results demonstrate good agreementwith experimental findings in terms of operating voltage and carbon deposition rate. The findings indicate that an increase in carbon deposition results in decreased porosity of anode electrode material and catalyst activity. Moreover, an upward trend in carbon deposition is observed with reduced prereforming degree, increased inlet speed, elevated operating temperature, decreased operating voltage, and higherhydrogen content in the fuel. Notably, while an increase in operating temperature, decrease in operating voltage, and higher proportion ofhydrogen lead to increased carbon deposition and severe decline in electrical performance, overall battery performance improves. These results suggest a close relationship between this phenomenon and methane cracking reaction.

0 引言

1 多物理场模拟及反应

   1.1 组分传递

   1.2 动量传递

   1.3 热量传递

   1.4 电荷守恒与传递模型

   1.5 电化学动力学模型

   1.6 积碳模型

   1.7 边界条件

   1.8 网格独立化验证

2 计算结果

   2.1 基本案例分析

   2.2 温度对积碳的影响

   2.3 氢气含量对积碳的影响

   2.4 入口速度对积碳的影响

   2.5 预重整对积碳的影响

   2.6 工作电压对积碳的影响

3 结语与展望