甲烷催化部分氧化制合成气催化剂的研究进展

Advances in catalysts for catalytic partial oxidation of methane to syngas

天然气是一种前景广阔的清洁燃料,甲烷作为天然气的主要成分,其高效利用具有重要的现实意义。在众多甲烷转化途径中,甲烷催化部分氧化(CPOM)具有能耗低、合成气组分适宜、反应迅速等优势。本文简要介绍了CPOM反应机理,即直接氧化机理和燃烧-重整机理;重点综述了过渡金属、贵金属、双金属和钙钛矿这四类CPOM催化剂的研究现状;分析了反应温度、反应气体碳氧比和反应空速对CPOM反应特性的影响;阐述了积炭和烧结这两种催化剂失活的主要原因及应对措施。根据研究结果可知,通过选取合适的催化剂组分、采用优化的制备方法、精确控制催化剂活性组分分布和微观结构等措施,可以保证更多的有效活性位更稳定地暴露在催化剂表面,以此提高催化性能(包括甲烷转化率、合成气选择性、合成气生成率、反应稳定性等)。最后指出了对CPOM催化剂微观结构的合理设计与可控制备以及对CPOM反应机理的深入研究仍将是今后关注的重点。

Natural gas is a promising clean fuel.The efficient use of methane,the major component of natural gas,is of great practical importance.Among many methane conversion routes,catalytic partial oxidation of methane(CPOM)has the advantages of low energy consumption,suitable syngas fraction and rapid reaction.This paper briefly introduced the CPOM reaction mechanisms(i.e.direct oxidation mechanism and combustion-reforming mechanism),reviewed the current research on four types of CPOM catalysts(i.e.transition metal,noble metal,bimetal and perovskite catalysts),analysed the effects of reaction temperature,carbon to oxygen molar ratio of reactant gas and reaction space velocity on CPOM reaction characteristics,and explained the two main causes of catalyst deactivation(i.e.carbon deposition and sintering)together with their countermeasures.According to the results of the research,the catalytic performance(including methane conversion,syngas selectivity,syngas yield,reaction stability)could be improved by selecting suitable catalyst components,adopting an optimized preparation method and precisely controlling the distribution of active components and microstructure of the catalyst.These method could ensure that more active sites are consistently exposed to the surface of catalyst.Finally,it was pointed out that the rational microstructure design and controlled synthesis of CPOM catalysts and the in-depth study of the CPOM reaction mechanism will remain the focus of future research.