GB1093791A - Process and apparatus for continuous regenerative distillation - Google Patents

Abstract

1,093,791. Distillation apparatus, vapour-compression type; desalination of water. DESAL Ltd. Feb. 24, 1965, No. 7883/65. Headings B1B and B1M. Impure water, e.g. sea water, is distilled in an evacuated vessel divided into an evaporato chamber 26 and a condenser chamber 27 by a zig-zag barrier comprising heat-conductive trays 28, 29 connected together and arrangec one above the other and in such a way tha each tray has a slight inclination to the hori zontal, trays 28 sloping in the opposite direc tion to trays 29. Trays 28 and 29 are shapes to form V-channels 170 and U-shaped chan nels 171, respectively. The water-to-be-distillec is first de-aerated by causing it to flow as film down the inside wall of a conical vessel 121 (Fig. 11) which is maintained under vacuum at pipe 125. The water is drawn into vessel 121 through perforations 124 in a circular manifold attached to inlet pipe 120 The de-aerated water is then preheated an< introduced through pipe 94 (Fig. 1) into the distillation vessel, where it is sprayed into the upper ends of trays 28. The water flows turbulently down channels 170, which are heated from below, and vapour is evolved. The vapour is withdrawn from chamber 26 by compressor 85 and is forced into chamber 27 on the other side of the zig-zag barrier, where it condenses on the undersides of trays 28, which are pre ferably coated with silicone material. The con denser chamber is preferably provided with ar electrically-operated vibrating-diaphragm. The condensate, i.e. pure water, immediately drips off the undersides of trays 28 into channels 171 of trays 29, and is withdrawn from the distil lation-vessel via pipe 99. Residual air, and some water-vapour, is drawn through close mesh screens at the upper ends of trays 29 into an axial pipe, and is then withdrawn from the distillation-vessel through pipe 107 by means of an ejector operated by a stream of pure water. Residual brine is withdrawn from the vessel via pipe 103, and may be recirculated to attain any desired degree of brine concentration. Alternatively, the brine may be passed to a second distillation vessel. It is stated that a centrifuge may be used in conjunction with, or in place of, compressor 85 in order to separate heavy water.