| Abstrakt: |
A review is presented of the designs and principles of operation of the systems for conversion of hydrocarbon fuel into synthesis gas (or syngas) to be used for energy generation in solid oxide fuel cells (SOFCs). Most SOFC systems employ methane or methane-rich (biogas, natural gas, industrial or petrochemical waste, etc.) as fuel due to their availability and ease of handling in contrast with hydrogen. The fuel-processing subsystem comprises approximately 50% of the overall electrochemical power facility. The generated heat, which is required for methane reforming, is recycled in fuel cells. Steam needed for the conversion of hydrocarbon fuel is generated in the anode compartment of the fuel cell or in an external steam generator recovering the heat of the exhaust gases of the fuel cell. The employed methods include steam reforming, partial oxidation of methane, carbon dioxide reforming of methane, and autothermal reforming. Steam reforming is the most extensively studied and widely used method. External reforming is employed for conversion of complex hydrocarbon fuels. For methane or natural gas, internal reforming is usually sufficient if the fuel recirculation ratio and steam to carbon and carbon to oxygen ratios are properly kept. Comparison of the existing methods for the production of syngas for SOFCs has revealed that steam reforming features the maximum steam consumption and the highest efficiency of the process. The partial oxidation of methane is an unsafe process due to the use of pure oxygen. Despite its low efficiency, the carbon dioxide conversion of methane offers the recovery of carbon dioxide and contributes additionally to decarbonization of the process. The autothermal reforming has merits of the steam reforming and the methane partial oxidation, but its implementation is a great challenge. [ABSTRACT FROM AUTHOR] |
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