Process and apparatus for the production of para-xylene

A process for producing para-xylene, the process comprising:

• (a) providing a first hydrocarbon feed comprising para-xylene, meta-xylene, ortho-xylene, and ethylbenzene to a first para-xylene adsorption section;
• (b) providing a second hydrocarbon feed comprising para-xylene, meta-xylene, ortho-xylene, and less ethylbenzene than the first hydrocarbon feed to a second para-xylene adsorption section;
• (c) recovering a first para-xylene-rich stream and a first para-xylene-depleted stream from the first hydrocarbon feed from the first para-xylene adsorption section;
• (d) recovering a second para-xylene-rich stream and a second para-xylene-depleted stream from the second hydrocarbon feed from the second para-xylene adsorption section;
• (e) separating the first and second para-xylene-depleted streams into an ethylbenzene-rich stream, which contains a majority portion of the ethylbenzene from the first and second para-xylene-depleted streams, and an ethylbenzene-depleted stream, which contains a minor portion of the ethylbenzene from the first and second para-xylene-depleted streams, in a divided wall raffinate column, wherein the first and second para-xylene-depleted streams are provided to the divided wall raffinate column on opposite sides of the dividing wall;
• (f) isomerizing meta-xylene, ortho-xylene, and ethylbenzene in at least a portion of the ethylbenzene-rich stream at least partially in the vapor phase back towards to an equilibrium concentration of xylene isomers to produce a second isomerized stream having a higher para-xylene concentration than the para-xylene-depleted stream;
• (g) isomerizing at least a portion of the ethylbenzene-depleted stream at least partially in the liquid phase back towards an equilibrium concentration of the xylenes isomers to produce a first isomerized stream having a higher para-xylene concentration than the para-xylene-depleted stream;
• (h) recycling at least a portion of the first isomerized stream to the first para-xylene adsorption section;
• and
• (i) recycling at least a portion of the second isomerized stream to the second para-xylene adsorption section.