| Solid oxide fuel cell(SOFC)is a green and environmentally friendly power generation equipment,which has the advantages of strong fuel selectivity,high power generation efficiency and low emissions,and has been favored by researchers.SOFC has two kinds of structure,flat plate and tubular,and tubular structure has attracted attention because of its excellent strength,stable structure at high temperature,and high thermal shock resistance.However,conventional SOFCs often generate carbon deposits at the anode when using hydrocarbon fuels,resulting in a sharp decline in cell performance.Starting from improving the performance of tubular SOFCs and improving the anti-carbon deposition performance of cells,this thesis systematically studied the performance of tubular SOFCs from the perspective of structural optimization of tubular cellss and hydrocarbon fuel reforming:The preparation process of tubular fuel cell is based on the dip-coating method,and the anode pore structure is improved by adjusting the binder content in the slurry composition of the anode support,so as to improve the electrochemical performance of the cell.When the PVB content is 9%,the power density at 800°C under H2 fuel is560.75 m W cm-2,and the performance with 13% PVB content under the same conditions is 382.04 m W cm-2,The SEM of the cell microstructure also show that the anode porosity of 9% PVB is high,which is convenient for the transmission of fuel gas,and improving the erformance of the cell.The thermal shock resistance of tubular SOFCs and the packaging and testing process of the cells are important indicators affecting the commercial application of the cells.Experiments show that the performance of the 9% PVB cell is attenuated by52.4% in the 30-cycle thermal cycle in the range of 700°C-300°C,and the attenuation is concentrated in the first five cycles,which is caused by particle precipitation and defects on the electrode side.Similarly,the current collector of the electrode of the large tubular cell prepared by the pouring method was optimized,and the maximum power density of the cells was increased from 73.21 m W cm-2 to 176.20 m W cm-2 at800°C,and the long-term performance of the cell was tested for 500 hours under hydrogen fuel,and the cell performance did not have obvious attenuation phenomenon,and the experiment proved that the improved electrode current collector effect was better.In order to alleviate the problem of carbon deposition of tubular fuel cells under ethanol fuel,tubular cells with 9% PVB content are used as the carrier,and dry reforming reactions with ethanol fuel are carried out by introducing CO2 into the fuel,The thesis has 37 pictures,3 tables,and 112 references.To further improve the fuel reforming effect,a Ni Fe2O4-GDC(NFO-GDC)reforming layer is added to the anode side of the cell.The study shows that when the ethanol content is 50%,the cell has the best internal reforming effect,the reaction of carbon dioxide and ethanol fuel is more sufficient,and the hydrogen production rate is higher.The CO2-ethanol dry reforming method and the hybrid reforming method with NFO-GDC anode reforming layer can effectively reduce the carbon deposition of tubular cells and improve the operating stability.The thesis has 36 pictures,3 tables,and 121 references. |
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