PartagerWater desalination thanks to freezing
A new desalination process involving freezing has been developed and offers an alternative to the shortcomings of other technologies such as distillation or inverted osmosis.
A new desalination process involving freezing has been developed and offers an alternative to the shortcomings of other technologies such as distillation or inverted osmosis.
Desalination by freezing has attracted attention as early as the 1960s as it allowed for less corrosion, required no pre-treatment and only little energy. More recently, its better environmental footprint is highlighted and the fact that 70% of global population lives less than 70 km away from coastlines.
The recent pilot crystallizer consists in a cooled tube immersed in a cylindrical double jacketed tank. The solution is poured into the tank and crystallization through freezing occurs on the external surface of the tube. A sweating stage is then necessary to purify the ice layer by melting the impure zones.
Experiments involved comparing operation in dynamic and static modes. The dynamic mode allowed for lower saline levels in the ice but the sweating stage still remained indispensable. The static process uses 10 kWh/m3 which is less than for inverted osmosis, but more than for distillation; and the dynamic mode tends to raise the system’s energy bill considerably (25 kWh/m3).
Revue Générale du Froid et du Conditionnement d’Air, May 2013
Desalination by freezing has attracted attention as early as the 1960s as it allowed for less corrosion, required no pre-treatment and only little energy. More recently, its better environmental footprint is highlighted and the fact that 70% of global population lives less than 70 km away from coastlines.
The recent pilot crystallizer consists in a cooled tube immersed in a cylindrical double jacketed tank. The solution is poured into the tank and crystallization through freezing occurs on the external surface of the tube. A sweating stage is then necessary to purify the ice layer by melting the impure zones.
Experiments involved comparing operation in dynamic and static modes. The dynamic mode allowed for lower saline levels in the ice but the sweating stage still remained indispensable. The static process uses 10 kWh/m3 which is less than for inverted osmosis, but more than for distillation; and the dynamic mode tends to raise the system’s energy bill considerably (25 kWh/m3).
Revue Générale du Froid et du Conditionnement d’Air, May 2013