煤气化燃料电池联合系统是下一代高效、清洁发电技术的重要选择之一。为避免煤合成气在固体氧化物燃料电池堆内由于CO歧化反应形成积碳，需对合成气进行一定程度加湿。利用替代映射方法构建了固体氧化物燃料电池堆多物理场多尺度模型，分析不同加湿程度下的电堆性能。加湿后，电堆内水煤气变换反应速率显著增大，并与H2和CO的电化学反应相互影响。在电堆内电池流道入口附近，水煤气变换反应尤为强烈，将CO快速转变为H2，补充了H2电化学反应的消耗。但加湿程度的增大也会降低H2能斯特电势，抑制流道入口段附近的H2电化学反应速率。距流道入口大于60 mm的部分，CO和H2分压接近平衡，水煤气变换反应减弱，气体反应速率受电化学反应控制。流道入口段H/O体积分数比和C/O体积分数比都较低，易发生积碳。50%以上的加湿可显著降低电堆内的积碳风险。加湿会造成电堆性能下降，采用的合成气组成条件下，100%加湿造成电堆性能损失4.65%。

Integrated gasification fuel cell system is one of the important candidates for the next generation clean and high efficiency power generation technology. In order to avoid carbon deposition caused by the carbon monoxide disproportionation reaction of the coal syngas in the solid oxide fuel cell stack, it is necessary to humidify the syngas to a certain extent. A multi-physics multi-scale model of the solid oxide fuel cell stack was constructed based on alternative mapping method to analyze the performance of the stack under different humidification levels. After humidification, the water gas shift reaction rate in the stack increases significantly and interacts with the electrochemical reactions of hydrogen and carbon monoxide. The water gas shift reaction is relatively strong near the inlet of the cell flow channel in the stack, rapidly converting CO to H2, and, supplementing the consumption of hydrogen in its electrochemical reaction. However, the increase of humidification degree will also reduce the Nernst potential of hydrogen and inhibit the electrochemical reaction rate of hydrogen near the inlet section of the flow channel. The partial pressures of carbon monoxide and hydrogen are close to equilibrium at a distance greater than 60 mm from the inlet of the flow passage, the water gas shift reaction is weakened, and the gas reaction rate is controlled by the electrochemical reaction. The H/O and C/O volume fraction ratio in the inlet section of the flow channel are both low, which is easy to occur carbon deposition. More than 50% humidification can significantly reduce the risk of carbon deposition in the stack. Humidification will also cause performance degradation of the stack. Under the conditions of syngas composition adopted in this paper, humidification of 100% will cause 4.65% performance degradation.

0 引言

1 SOFC电堆多物理场多尺度模型

   1.1 替代映射方法

   1.2 单元模型

   1.3 替代映射函数

   1.4 电堆模型

2 IGFC中SOFC电堆性能分析

   2.1 仿真参数与典型工况

   2.2 不同加湿程度电堆性能

   2.3 WGS和电化学反应的相互影响

   2.4 积碳安全边界

3 结论