The full set of scaling laws derived by Glicksman allows the hydrodynamic scale-up of fluidized bed reactors. In case of catalytic bed materials, changing the particle diameter during scale-up may have consequences for mass transfer, catalyst activity, selectivity and deactivation behavior. For catalytic fluidized bed reactors of Geldart B particles with vertical internals such as heat exchanger tubes, a sectoral scale-up approach is tested, that shall help to avoid this dilemma of chemistry vs. hydrodynamics. It was found that at least two rows of tubes are needed around the measurement position to neglect outer wall effects and to reach similar hydrodynamic properties. (C) 2014 Elsevier B.V. All rights reserved.