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.