Multi Effect Evaporators

Multiple Effect Evaporator (MEE) is a system consists of a sequence of heat exchangers – VLSs (vapor-liquid separators) used widely for many applications in industries to achieve evaporation and obtain desired concentration as output by using an efficient amount of heat source such as steam or hot water to evaporate water.Evaporation is normally stopped before the solute starts to precipitate in the operation of an evaporator. Most of the industrial evaporators have tubular heating surfaces. The tubes may be horizontal or vertical, long or short and the liquid may be inside or outside the tubes.A typical feeding method of multi-effect evaporators is forward feed, where both feed and steam are introduced in the first effect and the feed passed from effect to effect parallel to the vapor from the earlier effect. Feeding the steam results in the formation of a small amount of water vapor, which is used to heat the second effect. The vapor releases its latent heat and condense. The released latent heat would result in the formation of a smaller amount of vapor in the second effect. This process is repeated in subsequent effects, until the vapor temperature becomes close to the feed sea water temperature.