A multiphase CFD-based model with gas-solid hydrodynamics and chemical reactions is used to model flow behavior of gas and particles in the fuel reactor of chemical looping combustion process. The granular kinetic theory model is used to model the interaction of particle collisions. The friction stress of particles is considered to account for strain rate fluctuations and slow relaxation of the assembly to the yield surface. The reaction kinetics model of the fuel reactor is presented. The instantaneous mass fractions of both reactant and products are predicted, and the time averaged distributions are calculated in the fuel reactor. Simulated fuel reactor flows reveal a high weight fraction of unburned methane fuel in the flue gas along with CO2 and H2O. This behavior implies high fuel loss at the exit of the reactor and indicates the necessity to increase the residence time and improve mixing in the fuel reactor using circulating fluidized bed technology. (C) 2010 The Institution of Chemical Engineers. Published by Elsevier B.V. All rights reserved.