Patent ID: 8716541
Filing Date: 2014-05-06
Classification: B01D,B01J,C07C,Y02P

Abstract:
1. In a process for the production of paraxylene (PX) by a xylenes loop process including the steps of: (i) separating by distillation a C8+ aromatic feed into an overhead comprising xylenes and a bottoms comprising C9+ aromatics; (ii) recovering from said overhead comprising xylenes a high purity paraxylene (PX) stream by adsorption technology process; and a paraxylene-lean stream comprising metaxylene and orthoxylene; (iii) contacting said paraxylene-lean stream with an isomerization catalyst under vapor phase isomerization conditions sufficient to generate an equilibrium mixture of xylenes and passing said equilibrium mixture of xylenes to step (i); wherein the improvement comprises: (ia) separating said overhead from step (i) into a paraxylene-rich stream and a paraxylene-lean stream; (ib) passing said paraxylene-rich stream to step (ii) and contacting said paraxylene-lean stream with an isomerization catalyst containing a ZSM-5 zeolite under liquid phase isomerization conditions sufficient to generate an equilibrium mixture of xylenes and passing said equilibrium mixture of xylenes to step (i).