A three-phase hydrodynamic model is employed for the analysis of experimental data of chemical-looping reduction with nickel-based oxygen carriers and methane as the fuel. The model rigorously accounts for the mass, energy, and pressure balances, and the effect of oxygen carrier entrainment in the freeboard region. Model predictions are in good agreement with the relevant experimental data. The capability of the model to be used in the scale-up of fixed-bed kinetic studies of oxygen carriers to fluidized bed pilot-scale reactors is illustrated. The generality and validity of the model are analyzed, so that it can be used for further reactor design studies. In particular, sensitivity analyses, in terms of the crucial hydrodynamic parameters and correlations are carried out and the effects of important parameters, such as bubble size, mass transfer, oxygen carrier entrainment and reactions in the freeboard, on the performance of the chemical-looping reducer are investigated. (C) 2015 Elsevier Ltd. All rights reserved.