1. Simultaneous Heat and Mass Transfer
Chemical Engineering Department
Introduction to Drying Process
Presented by:
Umer Farooq
BEC-FA11-093
Dated:
05-06-2014
5. Why Drying is important…???
To reduce cost of transportation.
To make material more suitable for
handling.
To provide definite properties i-e free
flowing nature.
To remove moisture which may lead to
corrosion.
6. General Principle of Drying
If the material is exposed to air at
given temperature and humidity the
material will either lose or gain water
until an equilibrium condition is
established.
7. Forms of moisture
Bound moisture
• This is Water content retained in such
a way that it exert a vapour pressure
than that if free water at same
Free Moisture
• This is water which is in excess
amount of equilibrium moisture
content.
8. Rate of Drying
It is necessary to remove free
moisture from the surface and also
moisture from the interior of the
material.
9. General Methods of Drying
Natural Air
drying
Supercritical
drying
(superheated
steam
drying)
Freeze
drying
10. Industrial application
The drying process used in many
process industries i-e
In sugar industry, Pharmaceutical
industry, food industry, Paper industry,
and in caustic soda industry etc.