Xylenes are aromatic hydrocarbons naturally present in petroleum and crude oil. Since market demand has shown a growing tendency toward xylenes consumption, investigators have been seeking for more efficient ways of their production by converting surplus toluene and less useful heavy aromatics to more valuable xylenes by means of disproportionation/transalkylation reactions. In this study, a novel radial-flow packed bed reactor configuration has been proposed for transalkylation reactions owing to its remarkably lower pressure drop in comparison to axial flow packed bed reactors. According to the complex nature of the feedstock, an accomplished reaction network based on 18 pseudo-components and 39 reactions was applied to design the reactor more reliably. Afterwards, the differential evolution (DE) method was used in order to optimize the operating conditions of the proposed reactor design. Finally, the performance of the optimized reactor was compared with that of an optimized conventional axial flow packed bed reactor to ascertain the superiority of the proposed reactor configuration. (c) 2014 The Institution of Chemical Engineers. Published by Elsevier B.V. All rights reserved.