Drying in chemical Engineering context.

Drying is a mass transfer process resulting in the removal of water moisture or moisture from another solvent, by evaporation from a solid, semi-solid or liquid to end in a solid state. To achieve this, there must be a source of heat, and a sink of the vapor thus produced. In the most common case, a gas stream, e.g., air, applies the heat by convection and carries away the vapor as humidity.


The drying of materials is often the final operation in a manufacturing process, carried out immediately prior to packaging or dispatch. Drying is carried out for one or more of the following reasons:
(a) To reduce the cost of transport.
(b) To make a material more suitable for handling as, for example, with soap powders, and fertilizers.
(c) To provide definite properties, for example maintaining the free-flowing nature of salt.
(d) To remove moisture which otherwise may lead to corrosion.