Evaporation – Pharmaceutical Engineering B. Pharm Third Semester PDF Notes



Introduction to

Basic concept of phase equilibrium

Factors affecting

Theory of

Classification of

Parts of an

Construction &
working of evaporating still

Horizontal and
vertical tube evaporator

Multiple effect


At the end of this
notes student will be able to:

• Outline the
industrial applications of evaporation

• Explain the
differences between evaporation and distillation

• Describe the
basic concepts of phase equilibrium

• Discuss the
factors affecting evaporation process

• Explain the
theory of evaporation process

• Describe the
parts of an evaporator

• Discuss the
construction and working process of evaporating still

• Explain the
process of horizontal and vertical tube evaporator

• Discuss the
construction and working process of multiple effect evaporator

• Recommend
suitable evaporator for the evaporation process


• Evaporation is
nothing but a thermal separation process.

• Theoretically,
evaporation means simply vaporization from the surface of a liquid.

• Vaporization of
a liquid below its boiling point is called evaporation.

Thus, no boiling
occurs and the rate of vaporization depends on the diffusion of
vapour through the boundary layers above the liquid.

Evaporation is a
type of phase transition; it is the process by which molecules in a
liquid state (e.g. water) spontaneously become gaseous (e.g. water

Evaporation is a
unit operation of vaporizing large quantities of volatile liquid to
get a concentrated product

v/s Distillation


Vaporization takes
place below the boiling point

Takes only from the
surface of the liquid

There is no bubble
formation in evaporation

Not necessarily a
separation or purification technique. Vaporisation occurs rapidly


Vaporization takes
place at the boiling point

Takes place from
whole of the liquid

There is bubble

It is a separation
or purifying technique. It is a slow process

v/s Evaporation


It refers to the
removal of relatively small amounts of water from solid or nearly
solid material

In most cases drying
involves the removal of water at temperatures below its boiling point


It refers to the
removal of relatively large amounts of water from solutions

Removal of water by
boiling a solution- (wherever removing water is necessary)

For Detailed PDF Notes Click on Download Button

Leave a comment