GB1135132A - Improvements in or relating to desalination plant - Google Patents

Abstract

1,135,132. Desalination of water; multipleeffect distillation. J. A. R. FIFIELD. 31 Oct., 1967 [1 Sept., 1966], No. 39189/66. Heading B1B. Potable water is produced from saline water by pumping it into the upper end of a helical channel of closed cross section, the lowermost turn 11a of which is heated by circulation of hot fluid .through heat-exchange tubes 23a; the steam evolved from the saline water 23 in the lowermost turn passes through perforated pipes 26b into the heat-exchange tubes 23b and condenses therein, causing boiling of the saline water in the turn 11 b of the helical channel, this multiple-effect action being continued upwards through the other turns of the helical channel. Condensate, i.e. the required potable water, is withdrawn from heat-exchange tubes 23b, 23c ... through lines 17b, 17c ... into a common vertical pipe 18. Residual brine is pumped out of the lower end of the helical channel. The pressure in the vapour-space at the upper end of the channel is maintained below atmospheric pressure, e.g. at 0.5 p.s.i.a., while the pressure in the lower end is maintained at atmospheric pressure or above. The helical channel may be divided into sections by metal-mesh or by impervious partitions which have apertures below the surface of the saline water; and the condensate manifolds 25 may be connected to the vertical pipe 18 at suitably graded pressure points to give automatic pressure control down the helical channel. Effluent brine may be recirculated from the lower end of the helical channel into different turns of the helical channel, the brine forming liquid curtains in the turns in order to disentrain saline spray from the steam. The lowermost heat-exchange tubes 23a may be heated by steam or hot gas from a nuclear reactor 20. Two or more helical channels may be disposed side by side. The channels) and the supporting structure may be made of reinforced concrete.