The document provides an overview of drying processes and equipment used in pharmaceutical and industrial applications. It details the purpose and benefits of drying, classification of dryers, and specific types like spray, tray, fluidized bed, flash, drum, and vacuum dryers, along with their advantages and disadvantages. Additionally, it discusses general considerations for choosing dryers and applications in various industries.

1. RIPER
AUTONOMOUS
NAAC &
NBA (UG)
SIRO- DSIR
Raghavendra Institute of Pharmaceutical Education and Research - Autonomous
K.R.Palli Cross, Chiyyedu, Anantapuramu, A. P- 515721 1
DRYING EQUIPMENTS
A Seminar as a part of curricular requirement
for I year M. Pharm II semester
Presented by
K. VenkataSai Prasad (20L81S0402)
Department of Pharmaceutical Quality Assurance.

2. RIPER
AUTONOMOUS
NAAC &
NBA (UG)
SIRO- DSIR
Raghavendra Institute of Pharmaceutical Education and Research - Autonomous
K.R.Palli Cross, Chiyyedu, Anantapuramu, A. P- 515721 2
S.No Content
1 Drying
2 Purpose of drying
3 Drying equipments
4 Classification of dryers
5 Industrial dryers
6 References
Contents

3. RIPER
AUTONOMOUS
NAAC &
NBA (UG)
SIRO- DSIR
Raghavendra Institute of Pharmaceutical Education and Research - Autonomous
K.R.Palli Cross, Chiyyedu, Anantapuramu, A. P- 515721 3
DRYING AND DRYING EQUIPMENTS

4. RIPER
AUTONOMOUS
NAAC &
NBA (UG)
SIRO- DSIR
Raghavendra Institute of Pharmaceutical Education and Research - Autonomous
K.R.Palli Cross, Chiyyedu, Anantapuramu, A. P- 515721 4
 Drying is the simple process
of dehydrating foods until
there is not enough moisture
to support microbial
activity.
 If adequately dried and
properly stored, dehydrated
foods are shelf stable (safe
for storage at room
temperature).
DRYING/DEHYDRATION

5. RIPER
AUTONOMOUS
NAAC &
NBA (UG)
SIRO- DSIR
Raghavendra Institute of Pharmaceutical Education and Research - Autonomous
K.R.Palli Cross, Chiyyedu, Anantapuramu, A. P- 515721 5
• Increase in shelf life/preservation.
• Reduction in transportation cost.
• Easy material handling.
• Improve or maintain properties (flow ability or compressibility)
PURPOSE OF DRYING

6. RIPER
AUTONOMOUS
NAAC &
NBA (UG)
SIRO- DSIR
Raghavendra Institute of Pharmaceutical Education and Research - Autonomous
K.R.Palli Cross, Chiyyedu, Anantapuramu, A. P- 515721 6
• Dryer is a device that removes moisture by heating
the mass to a level where it becomes safe to store.
• Batch dryers are used for solid throughout (flows) below
50 kg/hr. Continuous dryers is preferred above 1000
kg/hr.
Drying equipments
MOISTURE
FEED
DRIED
PRODUCT
DRYER
HEAT

7. RIPER
AUTONOMOUS
NAAC &
NBA (UG)
SIRO- DSIR
Raghavendra Institute of Pharmaceutical Education and Research - Autonomous
K.R.Palli Cross, Chiyyedu, Anantapuramu, A. P- 515721 7
 Physical/Chemical properties of
• materials
 Production capacity
 Initial and final moisture content required
 Particle size distribution
 Temperature and drying characteristics
• Explosion and toxicological characteristics
Selection of equipment depends on

8. RIPER
AUTONOMOUS
NAAC &
NBA (UG)
SIRO- DSIR
Raghavendra Institute of Pharmaceutical Education and Research - Autonomous
K.R.Palli Cross, Chiyyedu, Anantapuramu, A. P- 515721 8
 Dryer must operate reliably, safely and economically.
 Operating and maintenance must not be excessive.
 Pollution must be controlled.
 Energy consumption must be minimized.
General consideration

9. RIPER
AUTONOMOUS
NAAC &
NBA (UG)
SIRO- DSIR
Raghavendra Institute of Pharmaceutical Education and Research - Autonomous
K.R.Palli Cross, Chiyyedu, Anantapuramu, A. P- 515721 9
Industrial dryers

10. RIPER
AUTONOMOUS
NAAC &
NBA (UG)
SIRO- DSIR
Raghavendra Institute of Pharmaceutical Education and Research - Autonomous
K.R.Palli Cross, Chiyyedu, Anantapuramu, A. P- 515721 10
Dryers
Heat transfer mode
Classification of dryers
Convection Combined
modes
Conduction Dielectric
Radiation
Infrared shelf
dryer
Sun dryer
Drum dyer
Agitated pan
dryer
Rotary dryer
Trays dryer
Flash dryer
Spray dryer
Fluid bed
dryer
Cabinet dryer
Tunnel dryer
Rotary dryer
Spouted bed
dryer
Microwave
oven
Microwave
tunnel
Radiofrequ
ency dryer
Microwave
convective dryer
Microwave
spouted bed dryer
Infrared
convective dryer
Radiofrequency
assisted heat
pump dryer

11. RIPER
AUTONOMOUS
NAAC &
NBA (UG)
SIRO- DSIR
Raghavendra Institute of Pharmaceutical Education and Research - Autonomous
K.R.Palli Cross, Chiyyedu, Anantapuramu, A. P- 515721 11
• Spray dryer
• Tray dryer
• Fluidized bed dryer
• Flash dryer
• Drum dryer
• Vacuum dryer
• Tunnel dryer
• Rotary dryer
• Freeze dryer
Industrial dryers

12. RIPER
AUTONOMOUS
NAAC &
NBA (UG)
SIRO- DSIR
Raghavendra Institute of Pharmaceutical Education and Research - Autonomous
K.R.Palli Cross, Chiyyedu, Anantapuramu, A. P- 515721 12
• The spray dryer provides a large surface area for heat and mass
transfer by atomizing the liquid to small droplets. These are
sprayed into a stream of hot air, so that each droplet dries to a
solid particle.
• The drying chamber resembles the cyclone ensuring good
circulation of air, to facilitate heat and mass transfer, and that
dried particles are separated by the centrifugal action
Spray dryer

13. RIPER
AUTONOMOUS
NAAC &
NBA (UG)
SIRO- DSIR
Raghavendra Institute of Pharmaceutical Education and Research - Autonomous
K.R.Palli Cross, Chiyyedu, Anantapuramu, A. P- 515721 13
• Product quality effectively
• controlled
• Product properties effectively controlled
• Suitable for heat sensitive foods eg: milk
• High tonnage equipment
• Corrosion problem minimized
• Good efficiency
Advantages

14. RIPER
AUTONOMOUS
NAAC &
NBA (UG)
SIRO- DSIR
Raghavendra Institute of Pharmaceutical Education and Research - Autonomous
K.R.Palli Cross, Chiyyedu, Anantapuramu, A. P- 515721 14
• Product quality effectively
• controlled
• Product properties effectively controlled
• Suitable for heat sensitive foods eg: milk
• High tonnage equipment
• Corrosion problem minimized
• Good efficiency
Disadvantages

15. RIPER
AUTONOMOUS
NAAC &
NBA (UG)
SIRO- DSIR
Raghavendra Institute of Pharmaceutical Education and Research - Autonomous
K.R.Palli Cross, Chiyyedu, Anantapuramu, A. P- 515721 15
• Drying of any substance in solution or in suspension form
• It is most useful for drying thermolabile materials eg:
antibiotics
• Suitable for large quantities solution
• Suitable for both soluble and insoluble substances
• It can produce spherical particles in the
• respiratory range
• Drying of milk, soap and detergents
Applications

16. RIPER
AUTONOMOUS
NAAC &
NBA (UG)
SIRO- DSIR
Raghavendra Institute of Pharmaceutical Education and Research - Autonomous
K.R.Palli Cross, Chiyyedu, Anantapuramu, A. P- 515721 16
• These types of dryers use trays or similar product holders to
expose the product to heated air in an enclosed space.
• The trays holding the product inside a cabinet or similar
enclosure are exposed to heated air so that dehydration will
proceed.
• Air movement over the product surface is at relatively high
velocities to ensure that heat and mass transfer will proceed in
an efficient manner.
• Operated as batch systems.
Tray dryer

17. RIPER
AUTONOMOUS
NAAC &
NBA (UG)
SIRO- DSIR
Raghavendra Institute of Pharmaceutical Education and Research - Autonomous
K.R.Palli Cross, Chiyyedu, Anantapuramu, A. P- 515721 17

18. RIPER
AUTONOMOUS
NAAC &
NBA (UG)
SIRO- DSIR
Raghavendra Institute of Pharmaceutical Education and Research - Autonomous
K.R.Palli Cross, Chiyyedu, Anantapuramu, A. P- 515721 18
• Simple in handling
• Lesser capital cost
Disadvantages
• Non-uniform drying of a product at different locations
within the system
• Time required for drying is more
• The major disadvantages of this type of dryers are the high
labor cost involved during loading and unloading of the
drying materials and the low capacities of the units
Advantages

19. RIPER
AUTONOMOUS
NAAC &
NBA (UG)
SIRO- DSIR
Raghavendra Institute of Pharmaceutical Education and Research - Autonomous
K.R.Palli Cross, Chiyyedu, Anantapuramu, A. P- 515721 19
• Mainly used for drying agricultural produce
• Drying foods E.g.( chillies and spices etc)
• Of potential use in pharmaceuticals, paints, textile and
other industries
Applications

20. RIPER
AUTONOMOUS
NAAC &
NBA (UG)
SIRO- DSIR
Raghavendra Institute of Pharmaceutical Education and Research - Autonomous
K.R.Palli Cross, Chiyyedu, Anantapuramu, A. P- 515721 20
• Fluid bed drying is most widely used technique for drying
pharmaceutical powders and granulation
• The direct contact between particles and air/gas is possible in
fluid bed systems.
• Here any type of inert gas or air is used.
• They can be designed in either batch or continuous type fluid
bed dryer.
• In fluidized bed dryer, hot air is passed at high pressure
through a perforated bottom of the container containing
granules to be dried.
Fluidized bed dryer

21. RIPER
AUTONOMOUS
NAAC &
NBA (UG)
SIRO- DSIR
Raghavendra Institute of Pharmaceutical Education and Research - Autonomous
K.R.Palli Cross, Chiyyedu, Anantapuramu, A. P- 515721 21
Cont..
• The hot gas surrounding every granule to completely dry
them.
• The material or granule are uniformly dried.
• The hot air/gas used for drying can be generated by either
steam coils or a combustion furnace.
• The angle of repose of gas-solid mixture is zero and it
• assumes the shape of vessel that contains it.
• Uniform conditions of temperature, composition and particle
size distribution is achieved throughout the bed because of
complete mixing between the solids and gas is obtained.

22. RIPER
AUTONOMOUS
NAAC &
NBA (UG)
SIRO- DSIR
Raghavendra Institute of Pharmaceutical Education and Research - Autonomous
K.R.Palli Cross, Chiyyedu, Anantapuramu, A. P- 515721 22
• Fluidized bed dryer requires less time to complete drying i.e., 20 to 40 min.
• Hot spots are observed in the dryer, because of its excellent mixing and
drying capacities.
• The thermal efficiency is 2 to 6 times greater than tray dryer
• It facilitates the drying of thermolabile substances, since contact time
for drying is short.
• It can be used as batch type or continuous type.
• The free movement of individual particles eliminates the risk of
soluble material migrating as may occur in static bed
Disadvantages
• Equipment is bulky.
• Expensive
Advantages

23. RIPER
AUTONOMOUS
NAAC &
NBA (UG)
SIRO- DSIR
Raghavendra Institute of Pharmaceutical Education and Research - Autonomous
K.R.Palli Cross, Chiyyedu, Anantapuramu, A. P- 515721 23
• Flash dryer utilizes superheated steam as the drying medium
have some unique quality and energy advantages over air
drying systems.
• Flash dryers consisting of inert media have been employed at
pilot scales to dry slurries and suspensions sprayed onto
them.
• The particles are coated thinly by the slurry and dried rapidly
as a thin film.
• Attrition due to inter-particle collisions and shrinkage
induced breakage of the dried film allows entrainment of
the dry powder into the drying gas for collection in cyclone
or baghouse.
Flash dryer

24. RIPER
AUTONOMOUS
NAAC &
NBA (UG)
SIRO- DSIR
Raghavendra Institute of Pharmaceutical Education and Research - Autonomous
K.R.Palli Cross, Chiyyedu, Anantapuramu, A. P- 515721 24

25. RIPER
AUTONOMOUS
NAAC &
NBA (UG)
SIRO- DSIR
Raghavendra Institute of Pharmaceutical Education and Research - Autonomous
K.R.Palli Cross, Chiyyedu, Anantapuramu, A. P- 515721 25
• Short contact time and parallel flow make possible to dry thermo
liable materials.
• The dryer needs only a very small area and can be installed outside a
building.
• The dryer is easy to control. The low material content in the dryer
enables equilibrium conditions to be reached very quickly.
• Due to small number of moving
• parts the maintenance cost is low.
• The capital cost are low in comparison with other types of
dryers.
• Simultaneous drying and transportation is useful for
material handling.
Advantages

26. RIPER
AUTONOMOUS
NAAC &
NBA (UG)
SIRO- DSIR
Raghavendra Institute of Pharmaceutical Education and Research - Autonomous
K.R.Palli Cross, Chiyyedu, Anantapuramu, A. P- 515721 26
• High efficiency of gas cleaning system is required.
• Dryer cannot be used for toxic materials.
• Not suitable for lumped materials.
• Risk of fire and explosion.
• Generally, not all the particles have same residence time in the dryer.
Applications
• Drying of heat sensitive products in this type of dryers is very
useful.
• They are successfully used in food, chemical, pharmaceutical,
mining, ceramic and wood industries.
• Widely used in plastic and
Disadvantages

27. RIPER
AUTONOMOUS
NAAC &
NBA (UG)
SIRO- DSIR
Raghavendra Institute of Pharmaceutical Education and Research - Autonomous
K.R.Palli Cross, Chiyyedu, Anantapuramu, A. P- 515721 27
• The drum dryer is an indirect type dryer in which the feed to
be dried is maintained in a thin film on a rotating steam
heated drum.
• The feed being dried is spread over the outside surface of the
dryer. Clinging to it drying continues ad the hot drum rotates.
• At the end of revolution, the drum comes to a ‘doctor blade’
which scrapes the dried film from the drum, when the
product has made about three quarter of a complete rotation
on the drum surface.
• The process is known as roller drying.
• Drum diameter: 0.5 to 6m and the length from 1m to 6m
• In operation, steam at temperature to 200 degree celsius heats
the inner surface of the drum.
Drum/Roller dryer

28. RIPER
AUTONOMOUS
NAAC &
NBA (UG)
SIRO- DSIR
Raghavendra Institute of Pharmaceutical Education and Research - Autonomous
K.R.Palli Cross, Chiyyedu, Anantapuramu, A. P- 515721 28

29. RIPER
AUTONOMOUS
NAAC &
NBA (UG)
SIRO- DSIR
Raghavendra Institute of Pharmaceutical Education and Research - Autonomous
K.R.Palli Cross, Chiyyedu, Anantapuramu, A. P- 515721 29
Classification
Drum dryers
Number of
drums pressure
A)Single
B)Double
drum
Feeding
arrangement
A)Atmospheric
B)Vacuum
A)Nip feed
B)Splash feed
C)Dip feed
D)Roller
A)Alloy steel
B)Stainless steel
C)Chrome
D)Nickel plate
steel
Material of
construction

30. RIPER
AUTONOMOUS
NAAC &
NBA (UG)
SIRO- DSIR
Raghavendra Institute of Pharmaceutical Education and Research - Autonomous
K.R.Palli Cross, Chiyyedu, Anantapuramu, A. P- 515721 30
• c

31. RIPER
AUTONOMOUS
NAAC &
NBA (UG)
SIRO- DSIR
Raghavendra Institute of Pharmaceutical Education and Research - Autonomous
K.R.Palli Cross, Chiyyedu, Anantapuramu, A. P- 515721 31
• Large production capacity
• Continuous operation
• Simple structure
• Easy to operate
• Less failure
• Low maintenance costs
Disadvantages
• Large equipment
• High one time investment
• Installation and removal are difficult
• Heat loss is large
• Thermal efficiency is low
• Material in dryer stay for long
Advantages

32. RIPER
AUTONOMOUS
NAAC &
NBA (UG)
SIRO- DSIR
Raghavendra Institute of Pharmaceutical Education and Research - Autonomous
K.R.Palli Cross, Chiyyedu, Anantapuramu, A. P- 515721 32
• This equipment is a good example of conduction drier.
• The vacuum oven consists of a jacketed vessel to withstand
vacuum within the oven
• There are supports for the shelves giving a larger area for
conduction heat transfer.
• The oven can be closed by a door.
• The oven is connected through a condenser and liquid
receiver to a vacuum pump.
• Operating pressure can be as low as
• 0.03 bar, at which pressures water boils at 25-35 degree
Celsius.
Vacuum dryer

33. RIPER
AUTONOMOUS
NAAC &
NBA (UG)
SIRO- DSIR
Raghavendra Institute of Pharmaceutical Education and Research - Autonomous
K.R.Palli Cross, Chiyyedu, Anantapuramu, A. P- 515721 33

34. RIPER
AUTONOMOUS
NAAC &
NBA (UG)
SIRO- DSIR
Raghavendra Institute of Pharmaceutical Education and Research - Autonomous
K.R.Palli Cross, Chiyyedu, Anantapuramu, A. P- 515721 34
• Drying takes place at low temperature.
• Maximum retention of nutrition.
• There is little air present, so there is minimum risk of
oxidation.
Disadvantages
• Drying takes place at low temperature.
• Maximum retention of nutrition.
• There is little air present, so there is minimum risk of
oxidation.
Applications
• Mainly used for puffed cereals
Advantages

35. RIPER
AUTONOMOUS
NAAC &
NBA (UG)
SIRO- DSIR
Raghavendra Institute of Pharmaceutical Education and Research - Autonomous
K.R.Palli Cross, Chiyyedu, Anantapuramu, A. P- 515721 35
Tunnel dryer
• It is modified form o the tray dryer in which oven is replaced by a
tunnel. The material to be dried is entered at one end and dried
material is collected form the other end of the tunnel.
Rotary drying
• A direct heated dryer uses the combustion gases generated by the
heater mixed with an artificially heated gas. This second gas is nearly
always common air, but it can be any inert gas.

36. RIPER
AUTONOMOUS
NAAC &
NBA (UG)
SIRO- DSIR
Raghavendra Institute of Pharmaceutical Education and Research - Autonomous
K.R.Palli Cross, Chiyyedu, Anantapuramu, A. P- 515721 36
• Freeze drying is a process in which water is removed from a
product after it is frozen and placed under a vacuum, allowing
the ice to change directly from solid to vapor without passing
through a liquid phase.
Freeze drying

37. RIPER
AUTONOMOUS
NAAC &
NBA (UG)
SIRO- DSIR
Raghavendra Institute of Pharmaceutical Education and Research - Autonomous
K.R.Palli Cross, Chiyyedu, Anantapuramu, A. P- 515721 37
Stages
• Freezing
a)Shell freezing
b)Centrifugal evaporative freezing
• Vacuum application stage
• Sublimation stage
Primary drying
Heat transfer
Vapour removal
Rate of drying
• Secondary drying
• Packaging

38. RIPER
AUTONOMOUS
NAAC &
NBA (UG)
SIRO- DSIR
Raghavendra Institute of Pharmaceutical Education and Research - Autonomous
K.R.Palli Cross, Chiyyedu, Anantapuramu, A. P- 515721 38
• Drying takes place at low
• temperature.
• Product is light and porous
• The porous form of the product gives ready solubility
• No concentration of solution prior to drying
• Nutrition retention.
• There is little air present, so there is minimum risk of
oxidation.
Advantages

39. RIPER
AUTONOMOUS
NAAC &
NBA (UG)
SIRO- DSIR
Raghavendra Institute of Pharmaceutical Education and Research - Autonomous
K.R.Palli Cross, Chiyyedu, Anantapuramu, A. P- 515721 39
• The porosity, ready solubility and complete dryness yield a
very hygroscopic product. Unless the products are dried in
their final container and sealed in situ, packing require
special conditions.
• The process is very slow.
• Uses complicated plant which is very expensive.
• Limited to certain types of valuable products
Applications
• The method is used for products that cannot be dried by any
other heat method. These include biological products.
E.g:antibiotics, blood products, vaccines, enzyme preparations
and microbiological cultures.
Disadvantages

40. RIPER
AUTONOMOUS
NAAC &
NBA (UG)
SIRO- DSIR
Raghavendra Institute of Pharmaceutical Education and Research - Autonomous
K.R.Palli Cross, Chiyyedu, Anantapuramu, A. P- 515721 40
1. APV Dryer Handbook-Invesnsys APV Technical Centre, USA.
2. Lykov M.V. Drying in the chemical industry/M.V. Lykov. M:
Chemistry-432p.
3. Fundamental of Food Engineering by D.G. Rao, 2010 by PHI
Learning Private Limited, New Delhi
4. https://gcwgandhinagar.com/econtent/document/1588156026Uni
t%20V%20Types%20of%20dryers%20and%20their%20applications
.pdf
References

41. RIPER
AUTONOMOUS
NAAC &
NBA (UG)
SIRO- DSIR
Raghavendra Institute of Pharmaceutical Education and Research - Autonomous
K.R.Palli Cross, Chiyyedu, Anantapuramu, A. P- 515721 41