我国合成气一步法制低碳烯烃催化剂研究新进展

New advances in the catalysts for one-step light olefins production from syngas in China

合成气一步法制低碳烯烃作为优势明显的非石油路线替代技术,至今仍未工业化的一个关键问题即催化剂的选择性较差。本文介绍了近十年来关于该催化剂的研究进展,分析了活性组分、助剂、载体及制备工艺分别对催化剂结构与性能的影响,认为Fe系与Co系是最有应用前景的催化剂,碱金属、碱土金属、过渡金属、稀土金属及非金属在调变催化剂酸碱性与电性上各自表现出不同的正作用,抑制了低碳烯烃的二次加氢副反应。分子筛等载体的表面性质与孔道结构可控,方便低碳烯烃从催化剂中扩散移除。浸渍、沉淀、溶胶-凝胶、熔融、水热、微波、超临界、真空干燥等工艺的改进或结合更有利于活性组分的分散和超细颗粒的形成。指出催化剂配合适宜的工艺及反应器才能发挥最大效能,才有可能突破F-T合成中低碳烯烃收率低的ASF规律的限制,实现合成气一步法制低碳烯烃的产业化推广。

As a promising non-oil route technology with obvious advantages,light olefins production from syngas through one step has not been industrialized owing to the low selectivity of the catalyst. Research progress on the catalyst in past decade was introduced,and influences of active components, additives,carriers and preparation technology on the structure and properties of the catalyst were analyzed in this paper. The Fe-based and Co-based catalysts were considered as the most promising catalysts,and alkali metal,alkaline earth metal,transition metal,rare earth metal and non-metal showed different positive effects in modulating acid-base properties and electrical properties of the catalyst, which prevented light olefins from secondary hydrogenation reaction. Carriers,such as molecular sieve,had controllable pore structure and surface area,and were convenient for the diffusion and removal of light olefins from the catalyst. Improvements and combinations of the technologies of impregnation,precipitation,sol-gel,melting,hydro-thermal,microwave,supercritical and vacuum drying are all favored for the dispersion of active components and formation of ultra-fine particles. It pointed out that only with an appropriate combination of the catalyst,process and reactor could it obtain the maximum efficiency,break the ASF rule of light olefins yield limitations in F-T synthesis, and achieve its industrialization promotion.