We propose a multiregion approach to allow for the computational fluid dynamic simulation of heterogeneous fixed bed reactors with a microkinetic description of the surface reactivity and the concomitant account for intraphase transport. A partitioned approach has been considered for the coupling between the different regions. The computational domain is split in different regions, which are characterized by different phenomena. The governing equations in the different regions of the domain are solved separately, followed by the achievement of the convergence at the boundaries through an iterative procedure. Overall, the resulting numerical framework allows for the dynamic solution of reacting flows over solid porous catalysts of arbitrary complex geometries with surface reactivity described by detailed microkinetic mechanisms. The capabilities of the numerical framework are tested through the analysis of complex geometries and large heterogeneous microkinetic models and the simulation of experimental data of H-2 combustion on Rh in conditions where internal mass transfer limitations are controlling. (C) 2015 Elsevier B.V. All rights reserved.