Transient Behavior of Electrodialysis Unit

Abstract

Electrodialysis (ED) is an electrochemical separation process in which charged membranes are applied to separate ionic species from one solution to another under an electric field [1]. In this work, the Computational Fluid Dynamics (CFD) modeling approach for the simulation of the ED unit was studied. Transport of species, current-voltage distribution, and fluid flow were simulated using the diffusion, Nernst-Planck, and Navier-Stokes equations. The commercial software (COMSOL 5.5) was used to solve the system of equations that govern this problem. The extracted results from the simulation model show how the voltage, current, velocity and concentration of the Na⁺ and Cl^- are distributed in the ED system.In this study the ED system operate at temperature 298K. The influence of different parameters such as flow rate, applied voltage  and different initial concentration of the sea water for counter flow has been studied. Besides, the transient behavior of the salt removal from the water was demonstrated in this work. The results show that by increasing applied voltage the removal efficiency increase but by increasing the flowrate and initial concentration of the seawater the removal efficiency of the salt decrease.