Influence of Stirring in Seawater Freeze Desalination Inside a Cooled Jacketed Crystallizer

This study investigates waste brine freeze desalination within a designed, cooled, jacketed crystallizer system. The study combines experimental findings with numerical simulation to interpret the feasibility of this approach. In the experimental phase, actual waste brine samples were collected from several seawater reverse osmosis (RO) units across the Arabian Gulf and analyzed for their ion composition. Furthermore, synthetic concentrated NaCl solution freezing inside the jacketed crystallizer by radial freezing from outer to center with stirring is carried out. The experimental results confirm that stirring enhances desalination efficiency, and it is found that 30 rpm’s efficiency outperforms 60 rpm. Moreover, a computational fluid dynamics (CFD) model of the crystallizer was also developed to understand heat and mass transfer during the freezing process under various conditions. The developed model captures the salinity growth trend, although discrepancies likely result from imperfect insulation at the top and bottom of the crystallizer. The results highlight the crucial role of stirring in homogenizing concentrated brine, effectively preventing the formation of highly concentrated layers at the freezing front. This research underscores the promise of seawater/waste brine freeze desalination as a sustainable and efficient solution for global freshwater scarcity.