Operation of Anode Supported Solid Oxide Fuel Cells on Methane and Natural Gas
INVENTION: A solid oxide fuel cell design and process has been developed at Northwestern to accommodate direct use of hydrocarbon fuels without chemical reforming. Conditions to foster stable operation below 800°C without coke formation have been demonstrated.ADVANTAGES: Fuel cell system directly utilizing hydrocarbon feed stocks without reforming offers simplified system design and process operation with improved unit efficiency.
SUMMARY: Solid oxide fuel cells (SOFCs) continue to promise clean power generation. Utilization of hydrogen and reformed hydrocarbon feed stocks for fuel cells is well established. Direct fuel cell oxidation of hydrocarbons, such as methane and natural gas, afford the potential for significant construction and operational efficiencies and economy. Prior art units operating directly on hydrocarbon fuels have encountered modest power densities, high anode catalyst requirements and electrode coking.
The SOFCs of this invention are constructed with nickel-yttria stabilized zirconia (Ni-YSZ) anodes, YSZ electrolyte and lanthanum strontium manganese (LSM) or LSM-YSZ cathodes to overcome the above stated limitations. Cells are fabricated in a unique design and stack configuration that afford improved mechanical strength, simplified gas manifolding and sealing, lower volume-weight and reduced internal electrical losses. Operation with methane or natural gas at 600-800°C exhibit similar power densities at 0.7V, achieving 0.96 W/cm2 at 800°C comparable with hydrogen feed stock in the system. Cells using methane feed at 700°C and 0.6V exhibited stable current density over 90 hours operation without anode carbon deposition (EDX and SEM analysis). Conditions for direct ethane fuel conversion have also been developed for these systems. The combination of component synthesis, design and operating conditions afford a SOFC system capable of direct hydrocarbon conversion without chemical reforming, and potential economic savings.
STATUS: A patent application has been filed.
Inventor(s): Jiang Liu, and Scott Barnett
Type of Offer: Licensing
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