ES339384A1 - Separation of fresh water from an aqueous solution by the high pressure inversion of the order of melting points - Google Patents

Abstract

A freeze-purification process for aqueous solutions, e.g. sea-water, employs a heatexchange medium which, under a relatively low pressure, is melted while absorbing the heat of freezing of the ice and, under a relatively high pressure, is solidified while supplying the heat of fusion of the ice. As shown, sea-water is filtered, heat exchanged with concentrated brine and product water, refrigerated and passed to an ice maker in which it is directly contacted with a slurry of a solid organic material under low pressure. The resultant ice, concentrated brine and organic liquid pass to a separator S 1 from which ice and brine are withdrawn by a pump J 1 and passed to an ice-washer. Part of the organic liquid from S 1 is passed to a highpressure ice melter by a high pressure pump J H and the remainder slurries the ice from the icewasher, this slurry being passed by a lowpressure pump J L to a set of vessels O 1 -O 4 in which it is pressurized by high-pressure streams of fresh water and organic slurry from a separator S 2 downstream of the ice melter, the pressurized slurry being supplied to the ice melter. The fresh water and organic slurry streams from vessels O 1 -O 4 are now at low pressure and are respectively removed as product and recycled to the ice maker. The heat exchange medium may be a pure compound or a eutectic or other mixture of substances suitable media are listed.