Multi-stage Flash Distillation
Seawater passes through the heating stages and is heated further in the heat recovery sections of each stage. After passing through the last heat recovery section, and before entering the first stage where flash-boiling (or flashing) occurs, the seawater is further heated in the brine heater using externally supplied steam. This raises the seawater to its highest temperature, after which it is passed through the various stages where flashing takes place. The vapors flash off the warm liquid and the salts exit with the remaining water.
The freshwater is formed by condensation of the water vapor, which is collected at each stage and passed on from stage to stage in parallel with the brine. At each stage, the product water is also flash-boiled so that it can be cooled and the surplus heat recovered for preheating the seawater.
The freshwater is formed by condensation of the water vapor, which is collected at each stage and passed on from stage to stage in parallel with the brine. At each stage, the product water is also flash-boiled so that it can be cooled and the surplus heat recovered for preheating the seawater.