Fuel Oxidation Efficiencies and Exhaust Composition in Solid Oxide Fuel Cells

详细信息    查看全文

• 作者：Michael B. Pomfret ; Oktay Demircan ; A. Mary Sukeshini ; Robert A. Walker
• 刊名：Environmental Science & Technology
• 出版年：2006
• 出版时间：September 1, 2006
• 年：2006
• 卷：40
• 期：17
• 页码：5574 - 5579
• 全文大小：217K
• 年卷期：v.40,no.17(September 1, 2006)
• ISSN：1520-5851

文摘

Solid oxide fuel cells (SOFCs) are electrochemical devicesthat rely on ion migration through a solid-state electrolyteto oxidize fuel and produce electricity. The present studyemploys Fourier transform infrared spectroscopy to quantifythe exhaust of an SOFC operating with fuel flows ofmethane over Ni/YSZ cermet anodes and butane over Ni/YSZ and Cu/CeO₂/YSZ cermet anodes. Data show thathydrocarbon fuels can participate in a variety of differentreactions including direct electrochemical oxidation,various reforming processes, and surface-catalyzed carbondeposition. These findings have direct consequences forassessing the environmental impact of SOFCs in terms of theexhaust discharged from devices operating with commonhydrocarbon fuel feeds. In the work presented below, ameasure of fuel oxidation efficiency is found by comparingthe partial pressure of CO₂ (P_CO2) in the SOFC exhaust tothe partial pressure of CO (P_CO). The fuel anode combinationwith the largest P_CO2/P_CO ratio is the C₄H₁₀ over Cu/CeO₂combination (0.628 ± 0.016). The CH₄ over Ni cell type hasthe second highest ratio (0.486 ± 0.023). The C₄H₁₀ overNi cell type gives a ratio of 0.224 ± 0.001. Attempts to balancethe carbon content of the fuel feed and exhaust lead topredictions of SOFC fuel oxidation mechanisms.