SSZ-13沸石粒径及硅铝比对甲醇制烯烃反应性能的影响

通过调控合成配方,以水热合成法制备一系列不同粒径及硅铝比的SSZ-13沸石,考察沸石孔道结构、酸性质与催化性能之间的关系。采用XRD、SEM、XRF、N₂吸附-脱附以及²⁷Al MAS NMR对沸石样品进行详细的表征,并评价其甲醇制烯烃反应(MTO)催化性能。结果表明,小晶粒SSZ-13沸石相对结晶度高、晶粒尺寸均一;在MTO中,小晶粒SSZ-13沸石的MTO催化寿命大幅高于大晶粒SSZ-13沸石;减小晶粒尺寸可改善分子扩散效率,在此基础上提高沸石的酸密度可增加其活性稳定性。

Effects of crystal size and silica-alumina ratio of SSZ-13 zeolite on the performance of methanol-to-olefins reaction

A series of SSZ-13 zeolites with different particle sizes,and silica-to-aluminum ratios were prep-ared by hydrothermal synthesis via adjusting the synthesis formula.The relationships between the zeolite pore structure,acidic properties,and catalytic performance were investigated.XRD,SEM,XRF,N₂ adsorption-desorption and ²⁷Al MAS NMR were adopted to characterize the zeolite samples in detail and their MTO catalytic performance were evaluated.The results show that the SSZ-13 zeolites with ultra-small crystal size have relatively high crystallinity and uniform grain size.The catalytic lifetime of the small crystal SSZ-13 zeolitesare significantly higher than that of the SSZ-13 zeolites with larger crystal size;the molecular diffusion efficiency can be improvedby reducing the grain size,therefore,the activity stability of the zeolite catalyst could be promoted by increasing the density of the strong acid sites.