DK137066C

1353444 Multiple-effect distillation; desalination of water R V J SAARI and E E HUHTAKOMSTO 21 April 1972 [22 April 1971] 18580/72: Heading B1B Liquid such as sea water is submitted to distillation in a multiple-effect apparatus wherein each effect is provided with a condeser 14..17 through which the seawater flows before it is introduced into the first effect 10, the arrangement being such that part of the vapour liberated in each effect is condensed on the codenser therein while the remainder is condensed in -the heat exchanger 36...38 of the next effect, and the condensates flow through heat exchangers 40, 41, and 43 in subsequent effects. Each main heat exchanger, e.g. heat exchanger 37 of effect 12, comprises a vertical tube 70 (Fig. 4) within which is disposed the condenser 72 corresponding to the condenser or the previous effect, i.e. condenser 15 of Fig. 1. Heat exchanger 76 corresponds to heat exchanger 40 in Fig. 1. Vapour from effect 11 flows into tube 70. Seawater from effect 11 rises up pipe 74 and. pipe 73 to anular space 71, passes through gap 84 and flows as a film down the outer surface of tube 70, while vapour from effect 11 is condensing within the tube. The steam liberated from the downflowing film of seawater rises through helical duct 80 to pipe 83 leading to the next effect. In Fig. 1, the steam leaving the last effect flows through pipe 48 with the condensates, flowing from heat exchangers 38, 41, 43, to ejector 49 operated by pumping distilled water from tank 51. In Fig. 2 (not shown) the steam leaving the last effect is drawn into a compressor driven by a diesel engine, and the compressed steam is used as heating- medium for the first effect.