不同燃料SOFC的理论电池电动势及其性能  

Theoretical electromotive force and performance of SOFC fed with different fuel gases

作　　者：熊洁[1] 焦成冉[2] 韩敏芳[3] 

机构地区：[1]枣庄学院化学化工与材料科学学院,山东枣庄277160 [2]枣庄学院机电工程学院,山东枣庄277160 [3]中国矿业大学(北京)化学与环境工程学院,煤气化燃料电池研究中心,北京100083

出　　处：《化工学报》2013年第7期2664-2671,共8页CIESC Journal

基　　金：国家重点基础研究发展计划项目(2012CB215404)~~

摘　　要：以NH3以及3%H2O增湿的H2、CH4、C3H8和煤炭地下气化(underground coal gasification,UCG)气为燃料,用最小Gibbs自由能法计算平衡气体组分和理论电池电动势,并测试在NiO-GDC‖GDC‖Ba0.9Co0.7Fe0.2Nb0.1O3-δ(B0.9CFN)阳极支撑固体氧化物燃料电池(SOFC)中的电池开路电压、电池性能和长期稳定性。结果表明,以上述气体作燃料的SOFC热力学计算理论电动势均高于1.05V,而由于GDC电解质在还原气氛下存在电子电导,导致碳氢燃料在NiO-GDC‖GDC‖B0.9CFN阳极支撑电池中的开路电压略小。中低温下,碳氢燃料相对缓慢的动力学过程和GDC电解质快速的氧离子传输速率,使得以UCG气、CH4和C3H8为燃料的电池实际积炭比理论预测少。以UCG气为燃料的SOFC在500、550、600和650℃的最高功率密度分别高达0.151、0.299、0.537和0.729W.cm-2,在0.6V恒压放电120h后性能没有明显衰减,且阳极表面无积炭产生,表明直接UCG气SOFC具有广阔的应用前景。The equilibrium species and theoretical electromotive force of cells fed with NH3 and 3% H2O humidified H2,CH4,C3H8 and underground coal gasification（UCG）gas on the basis of minimum Gibbs free energy were calculated,whilst the open circuit voltage（OCV）,V-I characteristics and long-term stability of NiO-GDC‖GDC‖Ba0.9Co0.7Fe0.2Nb0.1O3-δ（B0.9CFN）anode-supported cells operated in above five fuels were evaluated.The results showed that direct utilization of hydrocarbon fuels in anode could achieve a desirable electromotive force（EMF）no less than 1.05 V,while the OCV for ceria-based cells was comparatively poorer due to the presence of electronic conductivity.Besides,the synergy effect between stagnant kinetics of hydrocarbons reforming and the relatively sufficient O2-supply due to fast migration of oxide ions suppressed carbon deposition at low operating temperatures for ceria-based SOFC.Furthermore,the UCG gas fed cell exhibited peak power densities as high as 0.151,0.299,0.537 and 0.729 W·cm-2,respectively at 500,550,600 and 650℃,and showed no evident performance decay and carbon deposition on anode after discharging at 600℃ under a constant voltage of 0.6 V for 120 h,thereby demonstrating UCG gas is a promising fuel for direct utilization in SOFC.

关 键 词：固体氧化物燃料电池 UCG气 热力学平衡 电动势 积炭 

分 类 号：O646[理学—物理化学] TM911.4[理学—化学]