The hydrodynamics of rectangular spout-fluid beds are studied using Computational Fluid Dynamics-Discrete Element Method (CFD-DEM), a powerful approach in simulating gas-solid flows. Modified Navier-Stokes equations for the gas phase mass and momentum balance, and Newton's second law for the solid phase motion are coupled with Newton's third law of motion. Contact forces of particles and particle-wall collisions are based on a spring-damper system. The results show good agreement with 24,500 spherical particles for a column of 15 mm thickness and 150 mm width. The effect of column thickness and 3D effects are investigated by studying thicknesses of 30, 60, and 90 mm with 49,000, 98,000, and 147,000 particles. The effects of 2D and 3D CFD modeling on the pressure drop, air velocity, particle flux, and voidage profiles in different directions are compared in a column of thickness 30 mm. In addition to demonstrating the capability of CFD-DEM to model rectangular spout-fluid beds, it is shown that bed thickness and CFD modeling dimensions affect the flow and should be considered in numerical simulations. (C) 2015 Elsevier B.V. All rights reserved.