A falling film molecular distillation (FFMD) process was used in a pilot plant to fractionate a polyethylene wax (PE-Wax) into light paraffin wax (LP-Wax) and super-microcrystalline wax (SM-Wax). The pseudoization technique was applied to represent the molecular distribution of the PE-Wax by pseudo-components (PS1 and PS2). Investigation was made of the influences of the evaporator temperature (EVT), feed flow rate (FF), and condenser temperature (CT) on the percent recovery of distillate (D-p), the yield of PS1 in the distillate (Y-D_PS1), and the distillate flow rate/feed flow rate ratio (DF). The predictive models and the multi-response optimization provided decision criteria about the most suitable operating conditions for fractionating PE-Wax. The best experimental data for D-p, Y-D_PS1, and DF (63.4%, 81.5%, and 0.60, respectively) were obtained with EVT of 184 degrees C, FF of 1.81 kg/h, and CT of 28 degrees C, at 0.1 Pa. The LP-Wax, recovered mainly in the distillate, exhibited a normal distribution throughout the carbon number range from n-C-13 to n-C-30. The SM-Wax, recovered in the residue, showed a higher latent heat of storage (>169 kJ/kg), according to the phase-change performance of the material. These results offer new insights into processing PE-Wax to obtain value-added products with narrower carbon number distributions. (C) 2019 Institution of Chemical Engineers. Published by Elsevier B.V. All rights reserved.