Catalyst activity decay functions in liquid and vapour phase xylenes isomerization over H-Y zeolite

Abstract

A kinetic comparison of the deactivation of a zeolite catalyst in vapour and liquid phase isomerization of xylenes has been made. Quantitative data confirm the more rapid deactivation in the vapour phase. The liquid phase deactivation was best expressed by an exponential function, while the vapour phase was best expressed by a power law. Both systems correlated best using time on stream as the variable. Changes in isomerization selectivity were shown to result from differing variation of deactivation parameters with temperature. The faster deactivation of mordenite compared with Y zeolite was confirmed, and is consistent with the structural characteristics of the two zeolites. © 1982.