Numerical Modeling of Capacitive Deionization Desalination and Studying the Effect of Effective Parameters on Its Performance

Abstract

Due to the lack of fresh water, production of potable water is one of the important issues for mankind. Capacitive deionization is one of the methods that has recently attracted the attention of researchers due to its simplicity, low price and low energy consumption. The main challenge of this method is high energy consumption at high water concentrations. Therefore, this paper aims to investigate the effect of different effective parameters to improve the system performance. These parameters include feeding voltage, process time, electrode surface area and its capacitance value, overall transfer coefficient, volumetric flow rate and concentration of the feed water, and micropores’ volume, whose effects on energy consumption and number of cycles required to produce potable water are investigated. Results showed that the electrode capacitance and micropores’ volume decreased the necessary process cycles (reducing desalination process time) to produce potable water without significant changes in the energy consumption. The feeding voltage, volumetric flow rate and concentration of the feed water significantly affected the process time and energy consumption. For feed water concentration between 5 and 25 mM, results showed that the minimum values for the desalination process time, electrode surface area, and overall transfer coefficient, are 400 s, 50 cm2 and 0.9 µm/s, respectively. To improve the performance of desalination process in the capacitive deionization cell, development on the physical properties (increasing micropores) and the electrical properties (increasing capacitance value) of the electrodes, as the most important parameters, is suggested.

Keywords

• desalination
• capacitive deionization
• parametric study
• simulation