GB1021569A - Flash evaporators - Google Patents

Abstract

1,021,569. Flash evaporators; distillation of sea water. BALDWIN-LIMA HAMILTON CORPORATION. May 20, 1964 [May 20, 1963], No. 20921/64. Heading B1B. Liquids such as sea water are submitted to flash evaporation in an elongated vessel 12 throughout the length of which extends a slotshaped chamber 24 defined by parallel sidewalls 26, 28 but open at the bottom for the entry of liquid and open at the top for the discharge of liquid/vapour mixture, there being on each side of the chamber 24 a partition 38, 40 which extends laterially to the housing of the vessel and slopes down longitudinally from end-wall 20 to end-wall 22. Partitions 38 and 40 divide each of the spaces between chamber 24 and the housing into upper and lower compartments. The apparatus shown in Fig. 1 is part of a three-stage evaporator, stage 14 being interposed between stages 16 and 18. Hot brine flows from stage 16 through holes 50<SP>1</SP> and 52<SP>1</SP> in end-wall 20 into the lower compartments 42, 46 of stage 14. The brine flows under the bottom edges of side-walls 26, 28 into chamber 24 where flash vaporization of some of the water occurs because the pressure in stage 14 is lower than that in stage 16. The steam/brine mixture rises up chamber 24 and impinges on deflectors 54, 56 which causes the brine to fall freely so that the steam separates from it. The brine collects in the upper compartments 44, 48. Entrained droplets of brine are removed from the steam as it rises through mesh-separators 58, 60. The steam condenses on the outer surface of finnedtubes 64 which are cooled by the passage through them of sea water which is to be distilled. The condensate collects in pan 68, and flows out of the apparatus through pipe 70 as product, i.e. distilled water. The brine which collects in compartments 44, 48 flows through an increasing area to the openings 50 and 52 leading to the next stage 18. The liquidlevel in compartments 44 and 48 is above the upper edges 51, 53 of the openings in the endwall 22, so that the space above the brine in stage 14 is isolated from stage 18. A thirtystage process for the distillation of sea water is described, wherein the sea water is first mixed with the concentrated brine discharged from stage 1. The mixture so formed has a temperature of 100 ‹F. and is passed successively through the condenser tubes of stages 1 to 30, during which the temperature of the water rises to 200 ‹F. In stage 30 an addition of 10 ‹F. is made to the temperature of the water, e.g. by a steam heater ; and the water is then submitted to successive flash vaporization in stages 30 to 1. A three-stage apparatus is also described wherein each stage has six parallel riser-chambers 24 and each chamber is associated on both sides with a sloping partition. Each chamber may be provided with a butterfly valve near the upper end. The distillate is collected in a tank disposed in the housing below the riser-chambers. A plurality if such three-stage units may be connected side by side.