Multi-Stage Flash (MSF)

Multi-Stage Flash (MSF) evaporation desalination plants are based on flash evaporation in a cascade of stages (effects) at different pressure levels. In the brine-recirculation mode, the brine is recirculated through the system.

In the last stage of an MSF plant, the heated feed water is led into the pressure vessel where it partially evaporates in a flashing process due to the pressure decline. The vapour is used to preheat the feed water. The part of the brine that does not evaporate is sucked into the next stage which has a lower pressure. There, the same flashing and evaporation procedure takes place [
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