氟化铵对高温水热超稳Y型分子筛的改性研究

Modification Study of NH_4F on Ultrastable Y-Type Zeolites Prepared by High Temperature Steam Treatment

探索了氟化铵法制备高硅铝比超稳Ｙ型分子筛的可能性。系统地考察了反应时同、反应温度、氟化铵溶液加入量及溶液ｐＨ值对处理过程的影响。结果表明，在合适的处理条件下能制备出硅铝比达２０左右的超稳Ｙ型分子筛。改性后超稳Ｙ型分子筛的晶体结构热稳定性增加，脉冲微反试验的正已烷裂解活性下降而烯烃选择性得到提高。

The possibility of preparing high SiO_2/Al_2O_3 ratio zeolite by treating USY withNH_4F was explored.The effects on the process of treatment conditions,such as reaction time,reaction temperature,the amount of NH_4F solution,the pH of the solution,etc. were inves-tigated systematically.The results showed that ultra-stable Y zeolites of SiO_2/Al_2O_3 ratio rea-ching about 20 could be prepared under proper treatment conditions.The thermal stability ofthe crystal structure of modified USY zeolite is increased, and n-hexane cracking activity ina pulse micro-reactor is decreased, while the olefin selectivity is increased.