Evaporation

Evaporation 

Evaporation will be limited to concentrating aqueous solutions in a closed vessel or group of vessels

Evaporation is an energy-intensive process. Its efficiency can be improved by increasing the number of evaporators in series (effects), and some of the energy can be recovered by vapor recompression

Single effect evaporation

A conventional evaporator is heated by steam which condenses and transmits heat energy to the solution to be evaporated. As this solution boils it in turn releases vapor which may: – Either be condensed in a condenser, in which case the process is known as “single effect” evaporation.

Multiple effect evaporation

In a multiple effect evaporator, water is boiled in a sequence of vessels, each of which is at a lower pressure than the last. As the boiling point of the water decreases with pressure, the vapor produced in one vessel can be used to heat the next vessel. Only the first vessel requires a source of external heat.