Multiple-effect distillation

This article needs additional citations for verification. Please help improve this article by adding citations to reliable sources. Unsourced material may be challenged and removed. Find sources: "Multiple-effect distillation" – news · newspapers · books · scholar · JSTOR (April 2017) (Learn how and when to remove this message)

Multiple-effect distillation or multi-effect distillation (MED) is a distillation process often used for sea water desalination. It consists of multiple stages or "effects". In each stage the feed water is heated by steam in tubes, usually by spraying saline water onto them. Some of the water evaporates, and this steam flows into the tubes of the next stage (effect), heating and evaporating more water. Each stage essentially reuses the energy from the previous stage, with successively lower temperatures and pressures after each one. There are different configurations, such as forward-feed, backward-feed, etc.^[1] Additionally, between stages this steam uses some heat to preheat incoming saline water.^[2]