碳基燃料气体组成和运行温度对固体氧化物燃料电池开路电压的影响  

Effects of the compositions of carbon-base fuels and temperature on the open circuit voltage of solid oxide fuel cells

作　　者：陈志远[1,2] 王丽君[1,3] 赵海雷[2] 李福燊[2] 周国治[1,3] 

机构地区：[1]北京科技大学钢铁冶金新技术国家重点实验室,北京100083 [2]北京科技大学材料科学与工程学院,北京100083 [3]北京科技大学钢铁协同创新中心,北京100083

出　　处：《工程科学学报》2016年第11期1610-1619,共10页Chinese Journal of Engineering

基　　金：国家重点基础研究发展计划资助项目(2012cB215405);中国博士后科学基金资助项目(2015M570036)

摘　　要：以最小Gibbs自由能法计算固体氧化物燃料电池在不同组成碳基燃料气体组成下的理论积碳量,在此基础上讨论电池的理论开路电压(OCV),并测试在CO_2重整甲烷下Ni-YSZ‖YSZ‖LSM阳极支撑固体氧化物燃料电池的OCV.计算表明,理论积碳量从C-H-O相图的C角往积碳界线处以均匀速率减小.当积碳全部发生电化学氧化时,建议提高燃料气的碳氢比以获得较高OCV;反之则建议减小碳氢比.当燃气组分接近位于C-H-O相图中OCV界线(OCV=0 V)时,OCV会发生急剧下降.同样地,实验表明,当燃气中CO_2体积分数高于80%,会使得OCV大幅下降.综上可知,燃料气组分控制在积碳界线附近将有利于减少积碳并保证一定的电池发电性能.600℃时,在积碳界线的非积碳区侧,提高燃气中氢含量可提高OCV.而采用相同含量的CO_2稀释时,CH_4、H2和CO燃气下电池的OCV则依次降低.另外,实验表明升高外重整比例和降低温度,并不能显著提高OCV.The theoretical open circuit voltage （OCV） of solid oxide fuel cells （SOFCs） fed with carbon-based fuels and the amount of deposited carbon on the anode were calculated by the minimum Gibbs free energy method. The OCV values of Ni- YSZ II YSZ LI LSM anode-supported cells using methane-based fuels were experimentally measured. The resuks indicate that the amount of deposited carbon decreases from the C-comer of the C- H- 0 diagram to the carbon deposition boundary at a constant rate. In the case that most of deposited carbon is electrochemically oxidized, feeding fuels with high C： H ratio can enhance the value of OCV; Conversely, fuels with low C： H ratio are suggested. Theoretical analysis shows the rapidly decreasing value of OCV near the OCV boundary （OCV = 0 V）. Experimental results also reveal that the value of OCV dramatically decreases when the volume fraction of CO2 in fuel gas increases to be higher than 80%. These results imply that the compositions of carbon-based fuels should be near the carbon deposition boundary in the C-H-0 diagram, which is beneficial to suppress carbon deposition without significant OCV reduction. A relatively high value of OCV can be obtained at the H-corner in the non-carbon-deposition zone near the carbon deposition boundary, and the sequence of the value of OCV is CH4 〉 H2 〉 CO in the CO2-diluted ambiance at 600 ℃. Furthermore, the value of OCV can- not be significantly elevated via raising the proportion of external reforming or decreasing the temperature.

关 键 词：固体氧化物燃料电池 热力学 甲烷 开路电压 积碳 

分 类 号：TM911.4[电气工程—电力电子与电力传动] O646[理学—物理化学]