Patent ID: 6627783
Filing Date: 2003-09-30
Classification: C07C

Abstract:
A pressure swing adsorption process for separating para-xylene from a feed of C8 aromatics comprising a gaseous mixture comprising para-xylene, meta-xylene and ortho-xylene under substantially isothermal conditions comprising:(a) adsorbing the mixture onto an adsorbent comprising a para-selective adsorbent capable of selectively adsorbing para-xylene at a temperature and pressure at which at least 0.01 grams of para-xylene are adsorbed per gram of adsorbent; (b) producing a first effluent stream comprising a mixture of ortho-xylene and meta-xylene which contains no more than a total of about 20 mole percent of para-xylene based on total C8 aromatics; (c) selectively removing any feed present in the non-selective void volume; (d) selectively desorbing para-xylene by decreasing partial pressure of para-xylene; and (e) collecting the desorbed para-xylene to form a stream comprising para-xylene which contains no more than a total of about 50 mole percent of meta-xylene and ortho-xylene based on total C8 aromatics.