ZSM-5分子筛在甲醇转化制烯烃领域应用的研究进展

Research progress in the application of ZSM-5 molecular sieves in the methanol-to-olefin field

综述了ZSM-5分子筛在甲醇制烯烃反应特别是在甲醇制丙烯反应中的应用。介绍在接近工业反应条件下甲醇在ZSM-5分子筛上生成烯烃的反应机理,在较高反应温度下高碳数烯烃裂解是导致轻烯烃形成的主要反应路径;分析ZSM-5分子筛酸性及粒径对产品选择性及催化剂寿命的影响,由于ZSM-5分子筛酸性较强,直接用于甲醇制烯烃反应时低碳烯烃的选择性不高,而粒径小的ZSM-5分子筛扩散性能好,因而丙烯选择性得到提高。重点介绍小晶粒ZSM-5分子筛的研究进展,指出目前ZSM-5分子筛的研究方向一是对其进行酸性改性,二是制备酸度适中、粒径合适和具有介孔的多级结构ZSM-5分子筛。

The application of ZSM-5 molecular sieves for methanol-to-olefin（MTO） reaction, especially for methanol-to-propylene （MTP） reaction was reviewed. The reaction mechanism of methanol-to-olefin over ZSM-5 molecular sieves under the commercial condition was introduced. The main formation path of light olefins was the cracking of high carbon number olefins under higher reaction temperatures. Moreo- ver, the effects of the acidity and particle size of ZSM-5 molecular sieves on the selectivity to the product and catalyst life were analyzed. When it was directly applied in MTO reactions, the selectivity to light ole- fins was low because of its strong acidity of ZSM-5 molecular sieves, but ZSM-5 molecular sieves with smaller particle size led to higher selectivity to propene because its diffusion property was improved. Fur- thermore,the research progress in small grain ZSM-5 molecular sieves was focused on. It is pointed out that the main research directions for ZSM-5 molecular sieves are ： one is the acid modification of ZSM-5 molecular sieves, the other is the preparation of ZSM-5 molecular sieves with suitable acidity, appropriate particle size and hierarchical structure with meso-pores.