COMBINED HEAVY REFORMATE DEALKYLATION-TRANSALKYLATION PROCESS FOR MAXIMIZING XYLENES PRODUCTION

摘要

The present invention relates to a method of forming mixed xylenes from a heavy reformate using a dealkylation-transalkylation system that includes the step of introducing a heavy reformate containing methyl ethyl benzenes and tri-methyl benzenes and sufficiently free of toluene into the dealkylation stage with a hydrogen-containing material such that the heavy reformate and the hydrogen-containing material intermingle and contact a hydrodealkylation catalyst. The dealkylation-transalkylation system includes dealkylation stages, non-aromatic product gas separations and transalkylation stages. The BTEX component toluene forms from the reaction of methyl ethyl benzenes and hydrogen in the presence of the hydrodealkylation catalyst. The method also includes the step of introducing a dealkylated heavy reformate into the transalkylation stage such that the dealkylated heavy reformate contacts a transalkylation catalyst, forming a transalkylation stage product mixture that includes mixed xylenes.

主权项

1. A dealkylation-transalkylation system that is useful for forming mixed xylenes from a heavy reformate that includes both methyl ethyl benzenes and tri-methyl benzenes comprising:
a dealkylation stage that contains a hydrodealkylation catalyst, that is operable to receive both a hydrogen-containing material and the heavy reformate, and that is operable to produce a dealkylation stage product that contains toluene, tri-methyl benzenes and non-aromatic product gas; a non-aromatic product gas separations stage that is fluidly coupled to the dealkylation stage, that is operable to receive the dealkylation stage product, and that is operable to produce separately the non-aromatic product gas and a dealkylation heavy reformate that contains toluene and tri-methyl benzenes; and a transalkylation stage that is fluidly coupled to the non-aromatic product gas separations stage, that contains a transalkylation catalyst, that is operable to receive the dealkylation heavy reformate, and that is operable to produce a transalkylation stage product that contains mixed xylenes; wherein the hydrodealkylation catalyst is operable to selectively convert methyl ethyl benzenes and hydrogen into toluene and the non-aromatic product gas; wherein the transalkylation catalyst is operable to selectively convert tri-methyl benzenes and toluene into mixed xylenes; wherein the hydrodealkylation catalyst and the transalkylation catalyst are not the same material, and wherein the hydrodealkylation catalyst and the transalkylation catalyst are not contained in the same stage.