MULTI-EFFECT DISTILLATION (MED)

A Multi-effect distillation (MED) is a water desalination to produce clean fresh water from seawater. MED process is designed to produce distilled water/ potable water with steam or waste heat from power production or chemical processes, and/or to produce potable water. In a MED unit, the steam/heat passes through in the tubes of a number of stages of the unit to evaporate the SW sprayed in each stage/ effect. The steam in the tubes is condensed. The evaporated SW in the first effect is collected with evaporated brine in the flash boxes and goes into the tubes of the second effect. In flash boxes, a small pressure drop causes a small portion of brine to evaporate.This process continues until the last effect. For performance improvement of the MED, the thermal vapor compressor (TVC) is used. The TVC reduces the steam consumption in the MED. In the MED, TVC works by the superheated steam and it pressurizes the part of water vapor generated in the last effect.