Methods and apparatuses for producing xylene from propylbenzene

A method of producing xylene comprising:

• isolating a desired xylene isomer from a first xylene column stream in a xylene recovery unit, and producing a xylene raffinate stream;
• contacting the xylene raffinate stream and a propylbenzene containing feed with an isomerization catalyst at isomerization conditions to produce a xylene isomerization effluent stream comprising aromatic compounds having 8 carbon atoms (A8 compounds) and aromatic compounds having 9 to 10 carbon atoms (A9-10 compounds);
• separating the A8 compounds from the A9-10 compounds;
• and
• contacting the A9-10 compounds with a transalkylation catalyst at transalkylation conditions, and in the presence of toluene, to produce xylene.

An apparatus for producing xylene comprising:

• a xylene recovery unit configured to isolate a desired xylene isomer from a first xylene column stream;
• an isomerization unit coupled to the xylene recovery unit;
• a propylbenzene containing feed coupled to the isomerization unit;
• a transalkylation unit configured to transalkylate aromatic compounds having 9 or more carbon atoms with toluene to produce xylene;
• a xylene column coupled to the xylene recovery unit, wherein the xylene column is configured to transfer the first xylene column stream to the xylene recovery unit and to transfer a second xylene column stream to the transalkylation unit;
• and
• a fractionation zone coupled to the transalkylation unit and to the xylene column, wherein the fractionation zone is configured to transfer aromatic compounds having 8 or more carbons to the xylene column.