甲醇制烯烃新型分子筛发展探析

Discussion on development of novel molecular sieves for methanol-to-olefins

甲醇制烯烃属于快速反应,在稳态下反应受内扩散限制,反应产物乙烯、丙烯在扩散过程中易发生氢转移、低聚反应,产物选择性降低,催化剂易于结焦失活。为削弱内扩散对催化剂活性及产物选择性的影响,亚微米尺度、层片状、等级孔径或具有缺陷结构、载体支撑型、微孔及大孔型、中孔型微孔复合分子筛已成为甲醇制烯烃分子筛新的开发方向,并已取得了较好的研究进展。

The reaction of methanol-to-olefins is fast, and it is limited by internal diffusion in the steady state. The reactive products, ethylene and propylene, could easily take place the reactions of hydrogen transfer and oligomerization during the diffusion process, which could result in reducing the selectivity of desired products and the catalysts tending to be deactivated by coking. In order to eliminate the effect of the internal diffusion on the catalyst activity and the selectivity of desired products, composite molecular sieves with submicron size, laminated structures, graded pore diameters, or of carrier-supported type, with defects, micro-pores, macro-pores and medium sized micro-pores have become the new development orientation of the molecular sieves for methanol-to-olefins and some research progress has been obtained.