Structured reactors, and especially arranged reactors, are multiscale systems, in which the design on the small scale essentially determines the macroscopic reactor behaviour. In the present contribution, we propose a modelling strategy for the design and optimisation of an arranged flat-bed reforming reactor. It consists of three model levels, each describing the structure of the reactor on a different scale and detail level. The elements of this hierarchy are consistent and compatible, which means that results obtained with one model can be transferred to the other models. The possible applications of this model hierarchy range from estimation of pressure drop coefficients up to the integration of the structured reactor into a process plant. (C) 2011 Elsevier Ltd. All rights reserved.