Electrochlorination systems have become popular. Their hydrodynamic behavior affects the efficiency and power consumption but the reaction environment is complex due to the complex flow arising from gas evolution at the electrodes. Water reduction at the stainless steel cathode generates a large amount of small hydrogen bubbles being then, the only evolving gas at the electrodes that can modify the flow pattern inside the reactor. (Cl-2(8) generated at anode is rapidly hydrolyzed into hypochlorous acid or hypochlorite ion). This paper considers the hydrodynamic behavior of the two-phase flow using experimentally and modeled RTD curves, via a weakly coupled Euler-Euler model. Experimental data are in a qualitative agreement with the RTD model. (C) 2019 Institution of Chemical Engineers. Published by Elsevier B.V. All rights reserved.