GB1038058A - Improvements in the recovery of solvent from solutions containing dissolved non-volatile substances - Google Patents

Abstract

1,038,058. Distillation of liquids, particularly water. SALINE WATER CONVERSION CORPORATION. July 4, 1964, No. 27674/64. Heading B1B. Solvent is separated from solutions of non- volatile solutes, e.g. saline water, by heating the solution and introducing it through conduit 20 into enclosure 12 where the heated solution is distri-. buted by troughs 19 to the upper ends of plates 21 so that the solution flows in film-form down the sides of the plates, the pressure differential between the interior of the enclosure and the saturation pressure of the solution at any given point of the films being such that gradual vaporization (but no flashing) of the solvent takes place from the downflowing films. The concentrated solution collects in troughs 22, and the vapour flows on to condenser 11 which is provided with cooling coils 30, and is evacuated by air-pumps 36. Vertical slabs may be disposed between plates 21 to provide vapour-channels which gradually increase in width in the downward direction, thereby ensuring an appropriate decrease in pressure and suitable vapour velocities throughout the channels. Alternatively, the slabs may be dispensed with, and the plates may be tapered so that they diverge from each other in the downward direction as shown in Fig. 5. The vapours may be compressed before they are admitted to the condenser. The condensershell is supported by springs 32, and an expansion joint 34 between the shell and the evaporator permits free movement due to temperature variations. The condensate is withdrawn by pump 35. The concentrated solution flows from troughs 22 into troughs 24, and is then withdrawn through troughs 25 and conduit 23. In order to produce potable water from sea water, the latter is pumped through the condenser tubes 30 and thence through the condenser tubes of a steam-power plant; the hot sea water is then introduced into the film-evaporator. Alternatively, one stream of sea water may be pumped through the condenser tubes 30, and then discharged into the sea, while an independent water stream circulates between the auxiliary heat source and the evaporator. Several evaporator/ condenser units may be connected together to form a multi-stage system, each unit being disposed at a slightly lower level than the preceding one.