Nuclear Power Technology Development Section

NUCLEAR DESALINATION

Large-scale commercially available desalination processes can generally be classified into two categories:

Distillation processes that require mainly heat plus some electricity for ancillary equipment. The two major processes in use are:

Multi-Stage Flash (MSF) Distillation: This process produces vapor by heating the seawater close to its boiling temperature and passing it to a series of stages under successively decreasing pressures to induce flashing. The vapor produced is then condensed and cooled as distillate.

Multi-Effect Distillation (MED): In this process, vapor produced by an external heating steam source is multiplied by placing several evaporators (effects) in series under successively lower pressures, and using the vapor produced in each effect as a heat source for the next.
Reverse Osmosis (RO) processes

In this process, pure water is forced to pass under pressure through special semi-permeable membranes, while salt is rejected. The pressure differential must be high enough to overcome the natural tendency of water to move from the low salt concentration side of a membrane to the high concentration side, as defined by osmotic pressure.

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Last modified: March, 2004