Exergy and sensitivity analysis of electrodialysis reversal desalination plants

•Exergy analysis shows the stack with highest exergy destruction in an actual plant.•Sensitivity studies are then carried out on a modelled electrodialysis stack.•Concentration and current efficiency are the most significant variables.•Plant size is affected less at higher feed salinities compared to lower feed salinities.•A large variation in plant cost may occur while operating at higher concentrations.

In this paper, a normalized sensitivity analysis is done on an electrodialysis plant for various design and performance parameters. From the angle of design and performance, the most significant variables were the feed concentration and current efficiency, respectively. For the design aspect, plant size determination is affected less at higher feed salinities due to variations in the feed concentration, which seems to be favorable for high salinity applications. For the performance aspect, it is found that larger fluctuations in plant cost may occur while operating at higher feed concentrations. The desired diluate concentration and, thus, limiting current density as well as expected energy consumption may be more difficult to maintain at higher current efficiencies. Yet, the limiting current density is less sensitive at higher flow velocities. Therefore, the above problem could possibly be countered by using a combination of higher current efficiencies with higher flow velocities.