Fe2O3/Al2O3氧载体用于甲烷化学链燃烧：负载量与制备方法的影响

以不同方法制备了系列Fe₂O₃/Al₂O₃氧载体,采用XRD、H₂-TPR、CH₄-TPR、O₂-TPD和BET等分析技术对氧载体进行了表征。研究了不同Fe₂O₃负载量氧载体的甲烷化学链燃烧性能,考察了不同制备方法对Fe₂O₃/Al₂O₃氧载体结构、反应性和产物选择性的影响。结果表明,Fe₂O₃负载量对氧载体活性及产物中CO₂选择性的影响较大,负载量较低时氧载体活性较低且引起甲烷部分氧化产物CO含量增加。制备方法亦对氧载体与甲烷的反应活性有所影响,整体上共沉淀法制备的质量分数60％Fe₂O₃/Al₂O₃氧载体具有较高的氧化活性和化学链循环稳定性。其在反应温度850℃、反应时间15 min、30次循环后甲烷转化率及产物中CO₂选择性均未见明显降低。

Fe2O3/Al2O3 oxygen carriers for chemical looping combustion of methane: Influence of Fe2O3 loadings and preparation methods

A series of Fe₂O₃/Al₂O₃ oxygen carriers with different Fe₂O₃ loading were prepared by different methods and characterized by means of XRD, H₂-TPR, CH₄-TPR, O₂-TPD and BET technologies. The effects of the preparation methods on the Fe₂O₃/Al₂O₃ oxygen carrier structure, activity and the selectivity for CO₂ were also investigated. An obvious effect of Fe₂O₃ loading on the reactivity for methane oxidation and the CO₂ selectivity is observed. Lower Fe₂O₃ loading results in a lower reactivity of oxygen carrier and more CO content in the product gas. The reactivity of Fe₂O₃/Al₂O₃ is also affected by the preparation method of oxygen carrier. The Fe₂O₃/Al₂O₃ oxygen carrier with a Fe₂O₃ loading of 60% (mass ratio) has the best activity and redox stability for methane oxidation. Methane can be quickly converted to CO₂ and H₂O with higher selectivity at 850℃ for 15 min. After redox cycling in alternant methane/air atmosphere for 30 times, no decline in the conversion of methane and the formation of CO₂ is observed.