Roberto E Prada

US Patent:

51772957, Jan 5, 1993

Filed:

Dec 23, 1991

Appl. No.:

7/812262

Inventors:

Anil R. Oroskar - Downers Grove IL
Roberto E. Prada - Mount Prospect IL
James A. Johnson - Clarendon Hills IL
Gary C. Anderson - Clarendon Hills IL
Hermann A. Zinnen - Summit NJ

Assignee:

UOP - Des Plaines IL

International Classification:

C07C 700
C07C 712

US Classification:

585805

Abstract:

In the process flow scheme for chromatographically separating para-xylene from C. sub. 8 isomers containing substantial amounts of C. sub. 9 aromatic hydrocarbon impurities with BaX or KY zeolite adsorbent and heavy desorbents, e. g. , tetralin and diethyltoluene, a bottoms stream from the extract fractionation column containing desorbent is recycled to the separation unit and a sidecut stream, containing C. sub. 9 aromatic hydrocarbon impurities and a minor amount of the desorbent from the raffinate stream, is directed to the raffinate fractionation column, thereby removing C. sub. 9 aromatic hydrocarbons from the desorbent before recycling the desorbent to the separation unit, and preventing C. sub. 9 aromatics from building up in the desorbent input. A fractionator for the extract column bottoms stream is eliminated, lowering capital costs, and energy requirements for the raffinate column are reduced.