The core process of desalination is the Reverse Osmosis Process. It consists of a High pressure pump followed by an Energy Recovery device and the Reverse Osmosis Membranes.
Before entering the seawater reverse osmosis membranes, clarified seawater is pressurized by the High Pressure Pump typically between 55 and 85 bars, depending on the temperature and the salinity of the water.
The pressure drop over the RO membranes is about 1.5 to 2 bar, depending on the number of element per pressure vessel, so the concentrate is released at high pressure.
Thanks to Energy Recovery Devices, it is possible to reuse the energy from the concentrate flow. The concentrate is directed to the ERD, where it directly transfers its energy to part of the incoming feed water.
There are two main energy recovery concepts:
Energy Recovery Turbine (ERT)
Pressure Exchanger (PX)