【作者】 何方； 王华； 戴永年；

【Author】 He Fang, Wang Hua~*, Dai Yongnian (Faculty of Materials and Metallurgical Engineering, Kunming University of Science and Technology, Kunming 650093, China)

【机构】 昆明理工大学材料与冶金工程学院；

【摘要】 制备了新鲜的Fe2O₃甲烷燃烧催化剂,利用XRD、SEM和TG等分析手段对催化剂的性能进行了表征,并在质量比为1:1的Na₂CO₃和K₂CO₃熔融盐中研究了Fe₂O₃中的晶格氧对甲烷的催化燃烧性能。TG分析表明,Fe₂O₃与CH₄的反应分为两个阶段,第一个阶段从550℃开始,700℃结束,这一阶段里Fe₂O₃主要被还原成了Fe₃O₄,第二个阶段从800℃开始,Fe₃O₄被还原成了FeO和Fe:新生成的铁和低价铁氧化物与空气反应的TG曲线只出现一个增重阶段,从350"C开始质量开始显著增加,最后又重新生成了Fea03。在熔融碳酸盐体系进行的切换反应表明,在熔融盐中Fe₂O₃中的晶格氧能有效地对甲烷的燃烧过程进行催化,并且失去晶格氧的Fe₂O₃能与空气反应重新恢复其晶格氧,并且整个反应过程放出的热被储存在熔融盐热载体中,这更有利于甲烷的完全燃烧或部分氧化制合成气。因此,控制合适的反应条件,利用Fe₂O₃作为催化剂在熔融盐体系里使甲烷完全燃烧或部分氧化制合成气是可能的。更多还原

【Abstract】 Fe₂O₃ as a combustion catalyst was prepared and its characterizations and redox performance were studied using X-ray diffraction （XRD）, scanning electron microscope （SEM） and thermogravimetric analysis （TG）. The TG experimental results show that the reaction process between Fe₂O₃ and CH₄ can be divided into two steps. In the first step, Fe₂O₃ is reduced to Fe₃O₄ at temperature from 550℃ to 700℃. In the second step, Fe₃O₄ is reduced to FeO or Fe from 800℃ to 1000 ℃. In the other half redox circulation, newly-formed Fe, FeO and Fe₃O₄ are oxidized to Fe₂O₃ again by air flow in only one step at temperature of 350-800 ℃. A switching reaction system between 10%CH₄/N2 and air at a flow rate of 35Ncm³. min^-1 and at 800℃ was carried out in a stainless steel reactor, in which an alkali-metal carbonate mixture of Na₂CO₃ and K₂CO₃（weight ratio=1:1） and a desire weight ratio of Fe₂O₃ were placed. The results show that, in the CH₄ reaction step, the lattice oxygen in Fe₂O₃ canreact with CH₄ to form CO₂ and H₂O. And in the O₂ reaction step, lower valence iron oxide is reoxidized by molecular oxygen to Fe₂O₃. At the same time, the thermal energy discharged during the whole process is stored in the molten salts bath. These results indicate that methane can be oxidized by using the lattice oxygen in Fe₂O₃ in molten carbonate salts bath. The molten carbonate salts enjoy a high heat capacities and absorb the thermal energy of the reactions, which is favorable to methane combustion and synthesis gas production.更多还原