ZSM-5分子筛催化甲醇制汽油反应中的晶粒粒径效应研究

发布时间：2019-01-14 08:53

【摘要】：通过调控水热合成ZSM-5凝胶液中H_2O/Si物质的量比,实现了粒径为70、200、400和650 nm四种单分散ZSM-5的可控合成。采用XRD、TEM、BET和NH_3-TPD等多种表征对其微观结构进行分析,结合催化性能评价,考察了晶粒粒径对其催化甲醇制汽油反应性能的影响机制。结果表明,整体上随着ZSM-5晶粒粒径的增加,其外比表面积减小,结晶度提高,酸量呈现出先增加后基本不变的趋势。但外表面附着小晶粒的粒径为650 nm的分子筛体现出了大的外表面积和强的酸性。ZSM-5晶粒粒径的增加整体上降低了其催化MTG反应的寿命和最高收率。晶粒粒径为70 nm时,ZSM-5体现出了96 h的催化寿命和30.8%的最高收率。晶粒粒径为650 nm样品由于其大的外比表面积和较强的表面酸性,也体现出91 h的寿命。在大晶粒ZSM-5外表面附着生长小晶粒ZSM-5,是一种制备高性能催化剂的新方法。
[Abstract]:The controllable synthesis of monodisperse ZSM-5 with particle sizes of 70200400 and 650 nm was achieved by adjusting the ratio of H_2O/Si in hydrothermal synthesis of ZSM-5 gel solution. The microstructure of the catalyst was analyzed by XRD,TEM,BET and NH_3-TPD. The mechanism of the effect of grain size on the catalytic performance of methanol to gasoline was investigated in combination with the evaluation of catalytic performance. The results show that with the increase of ZSM-5 grain size, the external surface area decreases, the crystallinity increases, and the acid content increases first and then remains unchanged. However, the molecular sieve with a small grain size of 650 nm on the outer surface showed a large surface area and a strong acidity. The increase of the particle size of ZSM-5 decreased the lifetime and the highest yield of the catalytic MTG reaction as a whole. When the grain size is 70 nm, ZSM-5 exhibits a catalytic life of 96 h and a maximum yield of 30.8%. Because of its large external specific surface area and strong surface acidity, the grain size of 650 nm sample also exhibits 91 h lifetime. It is a new method to prepare high performance catalyst for the growth of small grain ZSM-5, on the outer surface of large grain ZSM-5.
【作者单位】：太原理工大学煤科学与技术教育部和山西省重点实验室;
【基金】：国家自然科学基金(21606160) 山西省科技基础平台建设项目(2015091009) 太原理工大学人才资助项目(tyut-rc201454a)资助~~
【分类号】：O643.36

【相似文献】