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Figure 2.6 EDR process.

2.2.2 Thermal Desalination

Thermal desalination or the most popular name distillation is the process of
evaporating seawater and condenses it to produce freshwater with low salinity
percent.

Thermal desalination stimulates the natural water cycle on Earth.

In the natural water cycle, water first evaporating from oceans due to sun rays and
thin rising in the steam form to the atmosphere, then steam formation as clouds and
finally it condenses and rains as freshwater. In Thermal desalination boilers and
flush vessels replace sun rays.

There are three popular systems in distillation :

1- Multi-stage flash (MSF ) :

MSF is the most popular system in distillation, that’s because it is the oldest
technique in distillation.

The main idea of MSF is based on the evaporation of saline seawater and
condensation of the generated steam. The necessary energy to increase seawater
temperature to the boiling point is supplied by steam coming from the boiler. The

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