Evaporation is the unit operation of raising the solute concentration in a solvent by heating a solution containing a non-volatile solute to a boiling point in which part of the solvent is vaporized and removed.
There are several occasions when evaporation operation is used in industrial production:
1. The concentrated dilute solution can be directly produced or the concentrated solution can be reprocessed (such as cooling crystallization) to produce solid products, such as the concentration of electrolytic baking lye, the concentration of sugar solution and the concentration of various fruit juices
2. At the same time, concentrate the solution and recycle the solvent, such as concentrated debenzene of organophosphorus pesticide benzene solution, evaporation of alcohol leaching solution in the production of Traditional Chinese medicine, etc
3. In order to obtain pure solvent, such as seawater desalination.
In short, evaporation is widely used in chemical, food, pharmaceutical and other industries.