Assessment of a pilot continuous freezing desalination system with vacuum-assisted brine extraction

Abstract

Freezing desalination (FD) is considered a potential alternative that addresses the shortage in water resources. FD commercialization is limited due to the intermittent nature of the FD process. An experimental investigation is conducted to a pilot continuous freeze desalination unit that employs vacuum-assisted brine extraction. The system is regarded as a first step to realize a continuous freeze desalination process that can be then commercialized. The proposed pilot FD unit has multiple brine extraction stages to reach the desired water salinity. Four distinct feed water salinity are tested. The results show that the unit has the potential to produce low-salinity water without the need for washing or crushing which causes significant mass loss. The results indicate that water is obtained at a salinity of 393 and 1225 ppm NaCl at feed water salinities equal 10,000 and 40,000 ppm NaCl, respectively. Furthermore, the system produces an approximate constant volume equal 850 mL which is around 28 % of feed water volume. The gain output ratio (GOR) of the system is 3.07, 2.97, 2.99 and 2.98 for feed water with salinity 10,000, 20,000, 30,000 and 40,000 ppm NaCl respectively.