水氯失衡对连续重整催化剂性能的影响

水氯平衡控制是重整催化剂性能发挥和保持的关键因素。考察了工业运转过程中催化剂的物化性能和催化性能的变化，对水氯失衡造成的催化剂失活和性能恢复进行了探讨。结果表明：长时间的水氯失衡，导致催化剂氯含量降低，使Pt发生严重积聚，运转1 967 天的催化剂中最大Pt晶粒直径达到90 nm；Pt的严重积聚导致催化剂活性和选择性大幅度下降，与新鲜催化剂相比，催化剂运转1 967 天后，C5+产物中芳烃含量下降12.89百分点，芳烃产率下降10.59百分点，积炭量增加0.77百分点；在常规氧氯化和还原条件下，特别是在连续重整装置的操作条件下，严重积聚的Pt晶粒的再分散速率非常慢，很难使运转催化剂恢复到新鲜催化剂的Pt分散水平。

EFFECT OF WATER-CHLORINE IMBALANCE ON THE PERFORMANCE OF CCR CATALYST

Water-chlorine balance of the system is very important for reforming catalyst to maintain good performance. The changes of physical-chemical properties and catalytic performance of CCR catalyst during commercial operation were studied. The deactivation of catalyst by water-chlorine imbalance and reactivation of said catalyst were investigated. Results show that the long-term imbalance of water-chlorine during operation leads to the decrease of chlorine content in catalyst, resulting in the severe agglomeration of Pt particles which reduce the activity and selectivity of catalyst significantly. The test results of a reforming catalyst collected from a CCR unit after running 1 967 d show that the maximum diameter of its Pt particle reaches 90 nm, as compared with fresh catalyst, its aromatics content in C5+ product is 12.89 percentage point lower, aromatics yield drops 10.59 percentage point and coke yield increases 0.77 percentage point. However, the redispersion of large Pt agglomerate is rather difficult under conventional oxychlorination and reduction conditions, especially under the operation conditions of CCR unit.