The Preparation And Study Of Co-generation Of Electricity And Ethylene Solid Oxide Fuel Cells

Solid oxide fuel cell?SOFC?is a reactor with high efficiency,no pollution and the product safety.Because of its advantages of modular structure and having a positive impact on optimizing energy structure and promoting the development of related high-tech industries,it has become an international research focus.Co-generation SOFCs batteries use alkanes as fuel gas and proton conducting material as an electrolyte.Under the catalysis of anode material,steam is generated at the cathode side,which avoids the disadvantage of dilution of fuel and reduces the complexity of the battery system.At the same time,ethylene,as a chemical intermediate of industrial value,is produced on the anode side,which provides a new idea for the development and research of solid oxide fuel cells.In this thesis,the preparation and forming process of electrolyte and electrode materials are mainly studied.In this thesis,BaCe_0.7Zr_0.2Y_0.1O_3–??BCZY?powders were prepared by sol-gel method and high temperature solid state method,furthermore,the effect of different experimental conditions of sol-gel method and high temperature solid state method on particle size of powders were further investigated.By comparing experiments: when the molar ratio of EDTA and citric acid with metallic ion is 1:1.25,the powder prepared by sol-gel method has the smallest particle size about 25 nm;and when the electrolyte powder is prepared by high temperature solid state method,the yield is higher than that of sol-gel process.When ZrO₂ is the source of zirconium,BCZY powder prepared at 1100 ? high sintering temperature 6 h is the smallest,which is beneficial to the optimization of subsequent electrolyte forming process.In this study,the thermal shrinkage curve of BCZY powder was tested and the sintering properties were studied.When the temperature is as high as 1590 ?,the BCZY powders do not have the contraction platform,and the sintering performance is not ideal.For this reason,CuO,ZnO and NiO were used as the sintering aids to prepare the electrolyte,and the effect of CuO was best.The different effects of CuO additive on the densification and sintering temperature of the electrolyte was investigated,when the amount of CuO is 1.8 wt%,the sintering temperature is 1300 ?,electrolyte performance is the best.Due to vanadium nitride is a kind of Pt-like type catalytic material,this paper used it as co-generation SOFCs anode material.Through studying the experiment,the sol-gel of ammonium vanadate was nitrided by urea in nitrogen atmosphere,vanadium nitride?VN?was prepared at the sintering temperature of 900 ? for 2 h.The anode supported electrolyte half cell was prepared by mixing,casting and sintering the CuO with the precursor during solid state synthesis of BCZY powder,and the anode was prepared by dipping method.An anode supported whole cell was prepared by screen printing.The performance of the cell was tested and the results show that when the battery is tested at 700?,the conversion of ethane was 30.8 %,ethylene selectivity is as high as 90.3 %,and the maximum power density of the battery reached up to 102 mW cm^-2.