Pneumatic conveying drying (PCD) has been widely used in industrial processes because it is regarded as a highly efficient technique in heating, and mass transfer of product operation. Despite the fact that the use of multi-stage drying techniques is now justifiable, many industrial complexes still use older single-stage systems. The purpose of this article is to investigate the effects of using a pneumatic dryer as a pre-dryer in PVC suspension production line at Bandar Imam Petrochemical Complex (BIPC). The current operating system in PVC suspension production line is fluidized bed drying. In the present work, computational fluid dynamics (CFD) is utilized to predict the hydrodynamics and drying mechanisms of a three-dimensional, dilute-phase, gas-solid turbulent flow in the laboratory-scale. The experimental study is carried out in two pilot-scale spiral pneumatic conveying dryers of diameter 5 cm and 13.45 m length and diameter 10 cm and 7.2 m length. As the main goals of this research, the influence of diameter and length of the dryer are investigated in two pilot-scale vertical pneumatic conveying dryers. In addition, the effects of gas velocity and temperature, particle temperature, mass flow rate and initial moisture content on the dryer performance are examined. The variations in the air velocity, air temperature, air pressure and particle moisture content are investigated along the length of the dryer. The results of energy analysis show that by using the pneumatic dryer as a pre-dryer, the specific energy consumption is reduced about 23.1%. (C) 2018 Elsevier B.V. All rights reserved.