Ultimately, however, the plant must be shut down and the scale removedĮither by chemical treatment or manual cleaning. Surfaces, for a boiling process type, can reduce scale build-up. Produce the rated quantities of distilled water or a fall-off in productionĬold shocking, the alternate rapid heating and cooling of the tube Scale formation will result in greater requirements for heating to Operating temperature, the flow rate and density of the brine. The rate of scale formation will depend upon the Is used to maintain the low pressure in the chambers and to remove anyĭuring the operation of evaporating plants, scale will form on the Returned to the sea water passing through the condensers. To heat the sea water and most of the latent heat from the flash steam is The concentrated sea water or brine remaining in the second-stageįlash chamber is drawn off by the brine pump. This steam is demistedĪnd condensed and, together with the distilled water from theįirst-stage, is drawn off by the distillate pump. Is at a lower pressure, and more water flashes off. The heated sea water passes to the second-stage flash chamber, which Steam as it rises and is then condensed in the first-stage condenser. A demister removes any water droplets from the The heated sea water then passes to the first-stage flash chamber where The feed pumpĬirculates sea water through the vapour condensers and the preheater. Place by admitting the liquid into chambers with progressively lowerĪ two-stage flash evaporator is shown in Figure. More than one stage of evaporation can take The sensible heatĬontent, water pressure and chamber pressure are designed to provide aĭesired rate of evaporation. it flashes, without boiling taking place. A combined brine and air ejector draws out the air andįlash evaporation is the result of a liquid containing a reasonableĪmount of sensible heat at a particular pressure being admitted to aĬhamber at a lower pressure. Remainder constantly overflows a weir and carries away the extra salty Regulated by a flow controller and about half the feed is evaporated. Pure water, which is drawn off by a distillate pump. In the condensing section the steam becomes ![]() The steam produced risesĪnd passes through a water separator or demister which prevents waterĭroplets passing through. Pressure in the chamber, the sea water boils. Steam is passed through the heater nest and, because of the reduced The sea water from the ship's services is first circulated through theĬondenser and then part of the outlet is provided as feed to the Pressure in the evaporator shell, boiling can take place at about 60☌. Sea water is boiled using energy from a heating coil, and by reducing the
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