A review of advances in freeze desalination and future prospects

Freeze desalination (FD) has several benefits compared to vaporization-based and membrane-based desalination methods. The FD process needs approximately 1/7th of the latent heat required by the vaporization-based desalination processes. The involvement of sub-zero temperature in FD reduces the risk of corrosion and scaling. This paper reviews the advances in FD methods involving stand-alone and hybrid methods that operate with and without utilizing the energy released during the re-gasification of liquefied natural gas. Moreover, the paper discusses the future focus areas for research and development to make FD a commercially feasible technology. Potable water was produced from brackish water and seawater by FD wherein the nucleation was achieved by ice seeding, the mixing of rejected salt from ice into the liquid phase was controlled appropriately, growth of ice crystals was slow, and liquid subcooling was maintained at approximately 4 K The post-treatment of obtained ice is needed to produce potable water if the process is instigated without ice seeding. The plant capacity of stand-alone progressive FD was higher than the stand-alone suspension FD of seawater. The integration of the falling-film, fractional thawing, and block FD method showed significantly improved plant capacity than the stand-alone suspension FD method. The energy consumption of stand-alone PFC and SFC-based desalination with latent heat recovery was reported close to the reverse osmosis (RO) method. The hybrid (integration of the suspension FD method with membrane distillation) FD method utilizing LNG cold energy consumed less energy than the conventional RO method.

Automated summary

Freeze desalination (FD) is a promising desalination method that requires less energy and reduces corrosion risk compared to other methods. This review paper discusses the advances in FD methods, including stand-alone and hybrid approaches, and explores future research focus. Results show that ice seeding in FD can produce potable water, while post-treatment is required without ice seeding. Stand-alone progressive FD has higher plant capacity than suspension FD, and integrating FD with membrane distillation significantly improves plant capacity.