以经过预重整反应的混合气为原料的固体氧化物燃料电池(SOFC)内部,甲烷蒸气重整反应与电化学反应同时发生在阳极多孔介质中,二者受到不同的操作与设计参数的影响,对电池总体性能起着决定性作用。编制了三维数值模拟程序,对由多孔阳极层、气体流动管道、固体支撑平板构成的单个复合管道进行了研究。结果显示:重整反应主要发生在多孔材料靠近流动管道的薄层内,只有靠近管道入口处才能在较深处进行;电化学反应发生在多孔层与电解质的交界面处;重整反应生成的H2、CO扩散到多孔材料底部参加电化学反应;电化学反应生成的热量供重整反应使用。说明研究范围内,SOFC阳极复合通道具有较好的传热、传质性能,化学/电化学反应存在较好的耦合关系。
The overall performance of solid oxide fuel cell (SOFC) is controlled by CH4 steam reforming reactions and CO, H2 electrochemical reactions, which take place in the porous anode simultaneously and are influenced by various operation and design parameters when pre-reformed methane/steam mixture is used. The composite duct consisted of a porous anode layer, fuel gas flow duct and solid plate. A fully three dimensional numerical, simulation program was developed to analyze the coupling mechanism of reforming and electrochemical reaction. Steam reforming was found mostly at the interface and entrance regions within the porous layer close to the fuel flow duct. Electrochemical reaction occurred on the surface between electrolyte and porous layer. CO, H2 produced by reforming reaction reached the bottom of porous layer and took part in electrochemical reaction. The heat required to keep internal steam reforming reaction was provided by the electrochemical reaction. The SOFC anode composite duct in this paper operated under proper conditions had good heat and mass transfer properties and good coupling relations between reforming and electrochemical reactions.