Paraxylene Separation Process

摘要

The invention relates to a p-xylene separation process wherein at least a portion of ethylbenzene present in an aromatics-containing feed is removed prior to isomerization. Aspects of the invention provide a process for producing p-xylene. The process includes providing a first mixture comprising ≧5.0 wt. % of aromatic C8 isomers, the C8 isomers comprising p-xylene and ethylbenzene. A p-xylene-containing portion and an ethylbenzene-containing portion are separated from the first mixture in a first separation stage to form a p-xylene-depleted raffinate. The first separation stage can include at least one simulated moving-bed adsorptive separation stage. At least a portion the p-xylene-depleted raffinate in the liquid phase is reacted to produce a reactor effluent comprising aromatic C8 isomers. The first mixture can be combined with ≧50.0 wt. % of the reactor effluent's aromatic C8 isomers. The combining can be carried out before and/or during the separating of the p-xylene and ethylbenzene portions.

主权项

1. A process for producing p-xylene, the process comprising:
(a) providing a first mixture comprising ≧5.0 wt. % of aromatic C8 isomers, the C8 isomers comprising p-xylene and ethylbenzene; (b) separating from the first mixture in a first separation stage a p-xylene-containing portion and (i) an ethylbenzene-containing portion and/or (ii) a non-aromatic containing portion, to form a p-xylene-depleted raffinate; (c) reacting at least a portion the p-xylene-depleted raffinate in the liquid phase to produce a reactor effluent comprising aromatic C8 isomers; (d) combining with the first mixture ≧50.0 wt. % of the reactor effluent's aromatic C8 isomers, the combining being carried out before and/or during the separating of (b), and (e) conducting away at least part of the separated ethylbenzene-containing portion and/or conducting away at least part of the separated non-aromatic containing portion.