A Monte Carlo model was proposed to characterize the fuel particles motion in a large-scale fluidized bed. The model describes the global motion of a fuel particle with a proper circulation throughout the bed, analyzing its behavior both in the freeboard and inside the bed. The model was validated with experimental results of the lateral mixing of fuel particles in a large-scale fluidized bed reported in the literature. The lateral displacement of the fuel particles and the residence time, both in the freeboard and inside the bed, were obtained from the model. From those data the lateral dispersion coefficient of the fuel particle was determined. The influence of the operational conditions on the lateral dispersion coefficient and on the maximum lateral distance reached by a fuel particle for different residence times in the bed was also analyzed. Finally, an optimal distance between feeding ports to ensure suitable fuel dispersion was obtained. (C) 2014 Elsevier Ltd. All rights reserved.