A comprehensive three-dimensional (3-D) heterogeneous reactor model was applied to simulate the turbulent gas-solid flow and reaction in a polydisperse fluid catalytic cracking (FCC) riser reactor. In order to describe the hydrodynamics of polydisperse solid catalyst particles and the FCC reaction, the reactor model combined the population balance model of the catalyst with the 14-lump reaction kinetic equations. The reactor model was also used to predict the distributions of system parameters in the complex gas-solid turbulent reacting flow in the riser, such as velocity, temperature and component concentrations. Furthermore, the effect of aggregation and breakage of particles on the catalyst particle size distribution (PSD) in the flow field was also considered in the proposed model. The simulation results showed that the particle breakage is significant in the FCC riser, which causes the particles become smaller. Besides, the simulated product yields considering particle aggregation and breakage agreed well with the on-site data in the plant. (c) 2013 Elsevier B.V. All rights reserved.