Vapor compression distillation plant

摘要

1,128,233. Evaporators of the vapour-compression type; distillation of water. AQUACHEM Inc. 7 Jan., 1966 [1 March, 1965], No. 951/66. Heading BIB. Liquid to be distilled, e.g. sea water, is preheated by passing it as cooling medium through the condensers of a multi-stage flash evaporator 25, the preheated liquid is submitted to distillation in a still 11 of the vapourcompression type, and the residual liquid is passed through line 30 to the first flash chamber of evaporator 25. Distillate is withdrawn from the heating-coil 21 of still 11 through line 35, and this distillate is cooled by passing it through heat-exchanger 36. Distillate is also withdrawn from evaporator 25 through line 31. Most of the distillate is produced by still 11, evaporator 25 acting primarily as a preheater for the incoming sea water. Brine is discharged from evaporator 25 through line 33: Some of the sea water to be distilled is supplied through line 26, and flows through the condensers in the right-hand half of evaporator 25. Sea water is also introduced into the system through line 37 and flows through a coil in heat-exchanger 36. The two streams of sea water are then united, acid is added through line 28, and the water enters vacuum-deaerator 29. Some of the deaerated water is pumped through the condensers of the left-hand half of evaporator 25, and the remainder flows 'through a coil in heatexchanger 36; the two streams are then united, and the preheated, deaerated water is introduced into still 11. Provision may be made for recirculating brine through the system. The compressor 20 may be of the conventional type. Alternatively, there may be used a pressure exchanger comprising a rotary valving element 671 (Fig. 4) supplied with high-pressure gas, e.g. steam, through line 80. This element, which is driven by a motor, has chambers which selectively communicate with four ports, which sequentially open and close as the element rotates. The vapour from still 50 is compressed by the creation of a shook wave 'by the high-ressure gas.