A comprehensive validated numerical model simulating the pneumatic transport of fine particles through various geometries has been developed using Computational Fluid Dynamics (CFD). The prediction reliability of the model was tested over a range of operational conditions, geometry layouts and particle size distributions (PSD). Simulation results have shown a reasonable agreement with published experimental data. The achieved results indicate that this CFD model has an extensive applicability for different geometries when an alternative recently developed drag force correlation is used. Furthermore, the effect of PSD was introduced in the validated model to gain a better understanding of particle motions during conveying. The CFD model with PSD also provided reliable results in various geometries. Numerical results reveal completely different particle size distributions in horizontal and vertical pneumatic conveying. Moreover, the formation and disintegration of particle ropes are both found to be controlled mainly by the behavior of large particles during transportation in a horizontal-bend-vertical pipeline. (C) 2019 Elsevier B.V. All rights reserved.