改性HZSM-5 上正己烷、正庚烷和甲基环戊烷芳构化反应规律的研究

STUDIES ON AROMATIZATION OF n HEXANE,n HEPTANE AND METHYLCYCLOPENTANE OVER MODIFIED HZSM-5

通过不同的方法对ＨＺＳＭ－５分子筛改性，用脉冲微反装置和连续流动固定床积分微反装置考察了硅铝比、载铂量、水热处理、高温焙烧对ＨＺＳＭ－５分子筛催化剂性能的影响，系统研究了催化剂的表面酸性质、载铂量和反应气氛对反应的影响。通过ＴＰＤ、ＸＲＤ、２７ＡｌＭＡＳＮＭＲ等方法测试催化剂的物理性质，研究了水热处理、高温焙烧和载铂前后ＨＺＳＭ－５分子筛的结构、表面酸性质及其变化的规律，并与反应性能关联，总结了正己烷、正庚烷及甲基环戊烷在分子筛上的反应规律。研究结果表明，在适当的条件下，经水热处理和高温焙烧后分子筛的活性和芳构化选择性增强，且载铂后高温焙烧产生最佳效果的温度较未载铂分子筛高；芳构化活性、分子筛强酸中心数与载铂量在实验范围内呈抛物性关系；氮气氛有利于芳构化选择性的提高。还比较了常压下Ｐｔ／ＺＳＭ－５和Ｐｔ／Ａｌ２Ｏ３对低碳烷烃的重整效果，发现前者具有较高的催化活性和较低的失活速率。

ZSM-5 was modified by various methods.Effects of its SiO 2/Al 2O 3 mole ratio,platinum loading,steam treatment and calcination on properties of ZSM-5 were studied by a pulse micro reaction unit as well as a fixed bed continuously flow integral micro reaction unit .The influence of surface acidity and platinum loading of catalysts,and the effects of gas media on aromatization were also examined.The changes of structure and surface acidity of catalysts measured by means of 27 Al MASNMR,TPD and XRD methods were correlated to catalytic activity.Steaming and calcination treatments enhanced aromatization over both PtHZSM 5 and HZSM 5.The presence of hydrogen or nitrogen as gas media benefited the aromatization reaction.Aromatization of n hexane was also studied on PtZSM 5 and Pt/Al 2O 3 under atomdspheric pressure.It is obvious that PtZSM 5 showed higher activity and lower deactivating rate than that of Pt/Al 2O 3.