脱盐，海水淡化
Consists mainly of sea-water desalination for industrial use or for obtaining drinking water. The main processes used at an industrial level are:
| Multi Stage Flash | Desalination is carried out by flashing sea-water in a vacuum, in a series of chambers arranged in a cascade, operating at decreasing temperatures and pressures. The chambers are equipped with a demister for separating the brine entrainments from the saturated steam and from a tube bank fed with sea-water that condenses the saturated steam and preheats the feed water. |
| Thermal compression | Desalination is carried out by heating sea-water to boiling temperature in an evaporator, with generation of saturated steam. The saturated steam, after retention in a separator to remove brine, is compressed and then superheated in a compressor. Afterwards the superheated steam moves into the evaporator to heat the incoming sea-water and is then condensed to desalinated water. |
| Reverse osmosis | Desalination is carried out by filtering sea-water through a semipermeable membrane, under a pressure that is higher than the osmotic pressure of sea-water. |