Optimal design and operation of electrodialysis for brackish-water desalination and for high-salinity brine concentration

Abstract

Electrodialysis (ED) is a desalination technology that has been deployed commercially for decades. However, few studies in the literature have looked at the optimal design and operation of these systems, especially for the concentration of high-salinity brines. In this paper, a set of constraints is defined to allow a fair comparison between different system sizes, designs, and operating conditions. The design and operation of ED are studied for the applications of brackish-water desalination and of high-salinity brine concentration for a fixed system size. The set of variables that determine the power consumption of a fixed-size system is reduced to include only the channel height and the velocity, with all the other design and operation variables depending on these two variables. After studying the minimization of power consumption for a fixed system size, the minimum costs associated with the different system sizes are studied, and the differing trends in brackish-water and high-salinity applications are compared. Finally this paper presents the effect of the cost modeling parameters on the trends of the optimal system size, current density, length, channel height, and velocity for the two applications studied.

Cost and energy needs of RO-ED-crystallizer systems for zero brine discharge seawater desalination

“…In a previous work, some of the authors of this paper had shown that state-of-the-art crystallizers are more efficient than state-of-the-art brine concentrators and suggested that research work should focus on improving the brine concentration step [14]. For seawater brine concentration, two proven technologies that can be used are mechanical vapor compressors (MVC) systems [10,[15][16][17][18] and electrodialysis (ED) systems [19][20][21][22][23][24][25][26]. Chung et al [14] had concluded that the potential for further efficiency improvements in MVC systems was limited.…”

A hierarchical model for novel schemes of electrodialysis desalination

“…However, in this case they have limited prediction capabilities, providing accurate results only under some conditions [47]. On the contrary, distributed parameters models [49][50][51][52][53][54][55][56] are more accurate, but at the cost of a larger implementation effort. In summary, with respect to the theoretical models, 1-D semi-empirical models are preferable as process simulators thanks to their features of versatility, robustness and effectiveness.…”

“…In the model recently proposed by Chehayeb and co-workers [41,49,53] the diffusion boundary layer thickness was calculated by experimental data on the Sherwood number, while mass transport in the boundary layer was simulated by the Maxwell-Stefan approach in order to predict concentration and electrical potential profiles and ionic and water fluxes. In ref [53] three different applications were simulated: brackish water desalination (from 3 to 0.35 g/kg), partial seawater desalination (from 35 to 1 g/kg) and brine concentration (from 70 to 200 g/kg).…”

Integrated Valorization of Desalination Brine through NaOH Recovery: Opportunities and Challenges

“…[32] Nevertheless,l ab-scale and large-scale implementations can differ considerably with respect to their optimal operating conditions;t hus,i dentification of the optimal conditions for ED scale-up that maximizes current efficiency and minimizes energy consumption is needed. [33,34] Ac ommon strategy for scaling up processes is to develop models that characterize the molecular transport phenomena and their corresponding energy usage.Q asem et al developed as implified model that took into consideration the Donnan potential, the voltage drop at the interface of the membrane and solution, which had significant effects on some design and performance factors. [35] Wright et al compared existing ED models and evaluated how simplifications affected the models computational time and results.…”