水蒸汽处理的HZSM-5沸石的酸性质及其对正构烷烃的裂解性能的研究

Studies of Acidic Properties and n-Alkane Cracking Performance of Steam Treated HZSM-5 Catalysts

用NH_3-TPD、IR技术和以正已烷、正十六烷为探针反应,研究了水蒸汽处理对HZSM-5催化剂酸性质及其倦化性能的影响,发现水蒸汽处理有效地脱除了能使正己烷裂解的活性中心,并发现通过水蒸汽处理,将酸中心数控制在1.60—1.00×10^(10)个/g范围内的HZSM-5催化剂均可作为石油脱腊催化剂。Mg、Fe改性后,将加深催化剂上长链烷烃的裂解程度。

NH_3-TPD, FT-IR techniques and probe cracking reaction of n-hexane and n-hexadecane were used to investigate the influence of steam treatment on acid and catalytical properties of HZSM-5 catalysts. It was found that with steam treatment, the acid sites where n-hexane cracking took place were effectively eliminated. If the concentration of acid sites of HZSM-5 catalysts was controlled by steam treatment in the range of 1.60-1.00×1020 sites/g, then all these catalysts could be used for oil dewaxing. It was also found that HZSM-5 catalysts modified with Mg and Fe could enhance the severity of n-hexadecane cracking.