Research Of SOFC Performance Feeded With CH₄ And Experience Of Changing Characteristic Over Anode

Solid oxide fuel cell (SOFC) is an all solid-state energy conversion device operated at high temperatures with the advantage of high efficiency, little pollution and no expensive metal catalyzer. SOFC attracts more and more attention allover the world for lack of power resources and environmental pollution. However, there are many problems to be solved such as carbon deposition on anode when feeded with CH4.Combining the status and trend of R&D in the field of SOFC and the conditions in our laboratory, we make this paper consist of several parts as following: the studies of SOFC which feed in CH₄ and the researches of carbon dioxide reforming of methane over nickel/alkaline earth metal oxide as anode materials, the main work and conclusions of this paper are as follows:(1) Tested the output performance of SOFC which feed in CH4 in different conditions. Generally speaking, the performance of SOFC increases with the rise of temperature and pressure. The dilution helium was causing a significant change in the reaction mechanism, from partial oxidation to complete oxidation with higher output performance. The output performance of SOFC increase to the top and then fall as the concentration of carrier gas increased. 85% is the feasible point with the highest power output. Compared with N₂, He is a better carrier.(2)Study the CO₂ reforming of CH4 by detecting the component of outlet gas with GC on-line to analyst the possible reaction over anode and find the reason of carbon deposition. According to the rise of ratio of CO2/CH4, the output performance of SOFC increases to the top and then fall. It is known that the curve of carbon formation has a turning point whose value is CO₂/CH4=1.67.At this point, carbon deposition is restrained. The effects of deposition on catalysis activation are unreversible. Though CO₂ can restrain carbon deposition, it could not remove all the carbon.(3) According to the researches of CO₂ reforming of CH₄ over nickel/alkaline earth and rare earth metal oxide as anode materials, the conclusions are obtained as following: The performance of Ni+YSZ cell has slightly down when mixed with CaO. However, the result of its running report shows that CaO is still an available promoter. Ni+CeO₂ cell, which carbon deposition is restrained, has better catalyst activity, lower interface impedance and best outputperformance;Ni+MgO cell can run in a long time without deterioration, so it is considered to be one of the best promoter of restraining carbon deposition.