The document explains the process of evaporation, which involves removing solvent from solutions by boiling, and discusses its importance in pharmaceutical engineering. It outlines factors affecting evaporation rates such as temperature, surface area, and agitation, as well as types of evaporators used. Additionally, it highlights applications of evaporation in the preparation of biological products, concentration of solutions, and water purification.

1. PHARMACEUTICAL ENGINEERING
UNIT-2 EVAPORATION
SUBMITTED TO: MR.L.GOPI M.PHARM
ASSISTANT PROFESSOR,
DEPARTMENT OF PHARMACEUTICS,
AADHIBHAWAN COLLEGE OF PHARMACY-RANTHAM
PREPARED BY: N.M.SWETHA
AADHIBHAWAN COLLEGE OF PHARMACY-RANTHAM

2. EVAPORATION
• “ Evaporation is the process of removal of solvent from the solution by
boiling the liquid n a suitable vessel & withdrawing the vapor, leaving a
concentrated product.”
• “Evaporation is the process of a substance in a liquid state changing to a
gaseous state due to an increase in temperature/pressure.”
• “Evaporation is the process of vaporizing large quantity of volatile liquid
to get concentrated product.” Equipment used for evaporation are known as
“Evaporator”.
• It is a surface phenomenon thus no boiling occurs . Either solution
suspension can be subjected to evaporation but the only condition is
that the liquid must be volatile & solute must be non-volatile.

3. OBJECTIVE
EVAPOURATION IS DONE BY :
 To get concentrated product.
 To remove water aqueous solution.
 To evaporate the sea water for develop drinking
water.
 To get solid from water which is used in boiler for
chemical process.

4. FACTORS AFFECTING EVAPORATION
 TEMPERATURE
 SURFACE AREA
 AGITATION
 VAPOUR PRESSURE
 TYPE OF PRODUCT REQUIRED
 DENSITY
 MOISTURE CONTENT
 TIME OF EVAPOURATION
 ECONOMIC FACTOR

5. • TEMPERATURE:
The evaporation rate is directly related to the temperature. As the temperature
increases, the rate of evaporation also increases. Because the temperature is rising,
the water molecules begin to move faster. As the kinetic energy is acquired by the
molecules and they escape from the surface to the vapor state. The heat is needed to
provide the latent heat of vaporization, and in general, the rate of evaporation is
controlled by the heat transfer rate. The rate of heat transfer depends on the
temperature gradient.
• SURFACE AREA:
The rate of evaporation is directly proportional to the surface area of the vessel
exposed to evaporation.

6. • AGITATION:
Agitation is necessary for evaporation.
• VAPOUR PRESSURE:
Liquids with a low boiling point evaporate quickly due to high vapor
pressure.
• TYPE OF PRODUCT REQUIRED:
The selection of the method and apparatus to be used for
evaporation depends upon the type of product required. For example, an open pan
produces liquid or dry concentrate while a film evaporator yields liquid concentrate.

7. • DENSITY:
As the density increases, the rate of evaporation decreases.
• TIME OF EVAPORATION:
Exposure to a relatively high temperature for a short time may be less
destructive of the active ingredients than a lower temperature with exposure for a
longer period. Film evaporators have used a fairly high temperature but the exposure
time is very short.
• ECONOMIC FACTORS:
When selecting the method and apparatus the economic factors are
important. Evaporators are designed to give maximum heat transfer to liquid.

8. • MOISTURE CONTENT:
Some drug constituents decompose more rapidly in the presence of moisture,
especially at the raised temperature. Hence, evaporation should be carried out at a
low controlled temperature.
TYPES OF EVAPORATORS
 Falling Film Evaporator.
 Forced Circulation Evaporators.
 LTV( Long Tube Vertical) Evaporators.
 Plate Evaporators.
 Mechanical Vapor Recompression (MVR).

9. FORCED CIRCULATION EVAPORATOR
• PRINCIPLE:
In forced circulation evaporator liquid is circulated through takes at
high pressure means of pump , hence boiling does not take place because boiling
point is elevated forced circulation of liquid also creed some form of agitation when
the liquid leaves the takes & enters the vapour head, pressure falls suddenly. This
flashing of super-heated liquor. Thus, evaporation is affected.
• CONSTRUCTION:
The steam jacketed takes are held between two rube sheet. The tube
measures osmotic pressure meter inside diameter & 2.5m long.

10. DIAGRAM

11. • WORKING :
Steam is introduced into calandria .Pump send the liquid to the tubes
with a positive velocity. As the liquid moves up through the tubes , it gets heated &
being to boil . As a result ,the vapour & liquid mixture rashes out of the tubes at high
velocity . this mixture strikes the deflector . The vapour enters the cyclone separator
&leaves the equipment. This concentration liquid returns to pump for further
evaporation. Finally , the concentrated product is collected.
• USES:
 It is used for thermolabile substance.
 It is used for to obtain concentration insulin & liver extracts.
 It is used for crystallizing operation.

12. • ADVANTAGES:
 The heat transfer coefficient are high due to rapid liquid movements.
 This evaporator is used for thermolabile substance because of rapid
evaporation.
 It is used for high viscous preparation because pumping mechanism is
use.
• DISADVANTAGES:
 The equipment is expensive because power is required for circulating the
liquids.
 Holing time of liquid is high.

13. APPLICATION
1. Evaporation is used in preparation of blood product such blood, plasms &
serum.
2. It is used for preparation of enzymes, hormones, antibodies, antibiotics.
3. It is used to prepare liquid extract or soft extract.
4. Used in the purification of vitamins.
5. Concentration of biological product.
6. In demineralization of water.
7. It is also used in formation of biological products like enzymes,
antibiotics& vitamin.

14. THANK YOU