煤基近零排放系统中固体氧化物燃料电池本体的模拟研究

Simulation Research of Solid Oxide Fuel Cell Integrated in Zero-emission Coal Systems

煤基近零排放(zero-emission coal,ZEC)系统采用固体氧化物燃料电池(solid oxide fuel cell,SOFC)进行清洁高效发电。以西门子发电集团研发的100 kW热电联产(combined heat and power,CHP)管式固体氧化物燃料电池堆为对象,采用ASPEN流程模拟软件借助FORTRAN编程搭建了SOFC本体模型,并依据文献报道的实际运行数据,对模型进行验证分析。结果表明,该SOFC模型具有良好的可靠性,可以用于后续ZEC系统的集成研究。同时该文就不同运行条件对SOFC工作性能的影响进行了分析,发现维持电池功率恒定,电池效率在燃料利用系数为0.8左右达到峰值;在其他条件不变时,增加电流密度会使燃料电池电压下降,燃料消耗量增加,电池效率降低,电池功率在电流密度约为3 500 mA时达到峰值;随着汽碳摩尔比的增加,乏燃料循环流率增加,初级重整炉出入口温度增加,甲烷转化率上升。

Solid oxide fuel cell （SOFC） is adopted in the zero emission （ZEC） coal system to generate environment- friendly electrical energy at high efficiency. A model of solid oxide fuel cell （SOFC） using ASPENTM PLUS with the assistance of FORTRAN based on the Siemens Power Generation Inc. （SPGI） 100 kW combined heat and power （CHP） SOFC was set up. The model was validated against data available in the literatures. Then, the model was used to do some sensitivity analyses about the influences of different parameters including the fuel utilization factor Kf, the current density J and the steam to carbon ratio Rsc on SOFC operation characteristics. Keeping the cell power constant, the cell efficiency was found reaching its peak value when Kf is about 0.8. When the other parameters were kept invariable, the amount of fuel exhausted increases with J increasing while the cell voltage and efficiency decrease; the cell power reaches its peak value when J is about 3 500 mA. The exhaust fuel recirculation flow rate, the pre-reformer inlet gas temperature and the methane reforming ratio all increase with Rsc increasing.