| Summary: | 碩士 === 國立清華大學 === 化學工程學系 === 94 === In this study, we developed a direct methane solid oxide fuel cells that used yttria-staled zirconia and Ni(60 wt%)-YSZ(100 wt%) and platinum as electrolyte , anode, cathode respectively. Main discussion in the experiment was the condition of carbon deposition and removal on direct methane solid oxide fuel cell.
With operating the process in the solid oxide fuel cells, the cathode would divide oxygen to oxide ions and transmit that to the anode by the electrolyte. According to this behavior, we could remove the carbon deposited on the anode without adding H2O in the fuel and use the deposited carbon to generate electricity. During the operation of methane, the bulk lattice oxygen of Ni-YSZ would spread outwards and react with methane. According to the oxygen pumping, when we closed methane inlet, we still could detect electricity.
Using methane as fuel under 50 mA/cm2 current density reacted with 5min, the carbon deposited on the anode that could remove easily by the self de-coking capability. With increasing methane reaction time (10min、30min),the amount of carbon increased and couldn't remove from the anode completely.
At lower current density (5 mA/cm2、1 mA/cm2), we couldn't remove all of the carbon by the self de-coking capability and that decreased the CO/CO2 ratio in the product gas. That meant that CO2 percentage in the product gas was increased under lower current density (5 mA/cm2、1 mA/cm2).
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