重整芳烃脱烯烃催化剂活性稳定性与表面酸性的关联

在N₂流中不同温度（20~300℃）下对固体酸催化剂进行热处理，然后进行NH₃程序升温脱附酸性表征和持续90d的重整芳烃脱烯烃反应实验，以研究催化剂失活动力学。结果表明，烯烃转化率均随着反应时间的延长而逐渐降低，催化剂结焦失活；催化剂热处理温度越高，其脱烯烃催化活性越低，活性稳定性越高。催化剂表面具有酸强度分布较窄的弱酸中心，随着催化剂处理温度提高，其表面酸密度逐渐降低，酸强度逐渐提高。催化剂表面酸密度越大和酸强度越高，其脱烯烃催化活性越高，而活性稳定性越差。300℃处理催化剂的活性稳定性较高，经90d持续反应，烯烃转化率从91.4%降至85.8%。

Relationship between Surface Acidity and Activity Stability of Solid Acid Catalyst for Removal of Trace Olefins from Reforming AromaticHydrocarbons

The solid acid catalyst was treated in N₂ flow at the temperature ranged from 20 to 300℃ and characterized by temperature programmed desorption of NH₃. The reaction experiments for the removal of trace olefins from reforming aromatic hydrocarbons were carried out in a fix-bed reactor for time on streams of 90 d with the catalyst treated at different temperatures. The deactivation kinetics of the catalyst was studied synchronously. The results indicated that the olefins conversion decreased and the catalyst deactivated by coke with the increase of time on stream. With the increase of heat-treatment temperature of catalyst, the activity stability of the catalyst became better and catalytic activity for the removal of trace olefins went lower. There were the weak acid sites with narrow acid strength distribution over the catalyst surface. With the increase of heat-treatment temperature of catalyst, the surface acid density of the catalyst reduced and the acid strength enhanced. The catalyst with larger acid density and higher acid strength over the surface exhibited the better catalytic activity and poor activity stability. The catalyst treated in N₂ flow at 300℃ had better activity stability with the olefins conversion decreased from 91.4% to 85.8% through time on stream for 90 d.