This document discusses different types of evaporators used in pharmaceutical manufacturing. It begins by defining evaporation as a process to concentrate liquids by removing solvent through application of heat. It then describes several types of evaporators in detail, including steam jacket kettles, horizontal tube evaporators, vertical tube evaporators, forced circulation evaporators, and multiple effect evaporators. The key factors influencing evaporation rate are also summarized.

1. EVAPORATION
B. PHARMACY SECOND YEAR
BY- SHALINI KESHAVRAO DHAWALE
ASSISTANT PROFESSOR
D. K. PATIL INSTITUTE OF PHARMACY, LOHA,NANDED

2. INTRODUCTION
 Evaporation is a process of converting dilute liquid/
solution to more concentrated liquid by removing solvent
by application of heat.
 In this process liquid is changes to gaseous state due to an
increase in temperature.
 Evaporation is a type of vaporization that occurs on the
surface of liquid as it changes into gaseous phase.
 Evaporation reduce the volume of product by some
significant amount without loss of nutrients component.
 To improve stability.
 To make transport and storage easier as evaporation
deacrese weight and volume of product.
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3. EVAPORATION
Advantages:
 Used in manufacturing of bulk drug in industries.
 In formulation of biological product like enzymes,
antibiotics, vitamins etc.
 Concentration of blood plasma and serum.
 Removal of water and solvent from fermentation broths.
 Concentration of herbal extract.
 In demineralization of water.
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4. FACTORS INFLUENCING THE RATE OF EVAPORATION
 Temperature: it is directly proportional to rate of evaporation.
 Vapour pressure: if vapour pressure of liquid is more then the
rate of evaporation will be more.
 Flow rate of Air: if air already has high concentration of the
substance evaporating , then the given substance evaporate
slowly.
 Inter molecular forces: stronger inter molecular forces will
require high energy to evaporate the molecule.
 Surface area: substance with large surface area will evaporate
faster
 Film and deposits: some product during concentration forms
film on surface of liquid, this film reduce evaporating surface.
 Density and Concentration
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5. EQUIPMENT USED FOR EVAPORATION
 Evaporation with heating medium in jacket: Steam jacket
kettle
 Evaporation with tubes placed horizontally: Horizontal
tube evaporator.
 Evaporation with tube placed vertically: Vertical tube
evaporator, basket type vertical tube evaporator.
 Evaporation with long tube
 Forced circulation evaporation
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6. STEAM JACKET KETTLE
 Principle: the conduction and convection mechanism is
involved in the evaporation process, steam provides heat
to the pan in which material is placed, temperature raises
and escaping tendency of solvent molecules into vapours
increases and enhance vaporisation of solvent.
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7. STEAM JACKET KETTLE
construction:
 Steam jacket kettle consist of hemispherical pans one is
kettle (inner )and other is called jacket( outer).
 These two pan are joined to each other enclosing a space
through which stem is passed.
 Several metals are used to construct kettle.
 At top of jacket inlet for stem is provided.
 Jacket has two outlet for uncondensed gases and another is
to remove condensate.
 Kettle is provided with one outlet for the product
discharge at the bottom.
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8. STEAM JACKET KETTLE
Uses-
 Used in food processing, pharmaceuticals and fine chemical
industries for evaporation of food items.
 Suitable for concentrating aqueous and thermostable liquors.
Advantages-
 simple design,
 Easy to clean and maintain no moving part so less ware and
tare.
 Stirring of contents and removal of product is easy.
Disadvantages-
 Capacity is less
 Efficiency is less
 It’s a batch process.
 Heating area decreases as the product gets more concentrated.
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9. HORIZONTAL TUBE EVAPORATOR
Principle- tubes are immersed inside the pool of the liquid to
be evaporated and steam is passed inside the tube. Heat is
transferred from the stem to the liquid.
Liquid is heated and librated vapours are removed from
the top, concentrated product is removed from the bottom.
Construction- it consist of vertical cylindrical body with
dome shaped top and bottom.
 These evaporators are of iron or steel plate with 2m
diameter and 3m height.
 Heating compartment contains horizontal tubes.
 Diameter of tubes is usually 2 to 3 inches.
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10. Horizontal tube evaporator
 Construction-
 The tubes are further secured by the use of gasket to avoid
slippage.
 Steam compartment and condensate are place on the either
side of the heating compartment
 Stem is introduced from one end and condensate is
removed from another end.
 Feed liquor is introduced at any convenient point such a
way that it covers all the tubes.
 Vapours are removed from the top and concentrated
product is removed from the top.
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11. HORIZONTAL TUBE EVAPORATOR
 Working- Feed liquor is
introduced in the heating
compartment till it covers all
the tubes
 Steam is introduced from the
steam compartment
 Heat from the steam is
supplied to the tubes and
ultimately to the product.
 Liquid is heated by the steam
and vapours are removed from
the top.
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12. HORIZONTAL TUBE EVAPORATOR
Use –
 Best Suitable for non-viscous solutions.
 to prepare cascara extract.
Advantages-
 More efficient than evaporating pans.
 heating surface is less.
Disadvantages-
 Heat transfer is not efficient.
 Crystals can deposit on tubes.
 Not suitable for viscous solutions.
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13. VERTICAL TUBE EVAPORATOR
Principle- in this evaporator liquid
is inside the tube and steam is
outside the tubes.
Construction:
This consists of a long tubular
heating element incorporating
the tubes 25 mm to 50 mm and
3 to 10 meters in length.
 And also it contains at the top a
separator or vapour space for
removing entrained liquid from
the vapour.
 The deflector is provided just
above the tube sheet.
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14. VERTICAL TUBE EVAPORATOR
 Working:
 The feed at near boiling is fed to the bottom of the
evaporator.
 It is then pumped inside the tubes. Steam is provided
on the shell side.
 Liquid and vapour are separated in the vapour
separator at the top.
 Deflector acts as both primary separator
and foam breaker. Multiple effects are used to achieve
higher steam economy
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15. FORCED CIRCULATION EVAPORATOR
 Principle- Forced circulation
evaporator working involves the
liquor being pumped through
tubes at high velocity. The liquor
goes from the bottom of the cone
of the vapour body, through the
tubes and then back into the
vapour body. When the liquid
comes out of the tubes and enters
the vapour body, there is a
sudden fall in pressure, leading
to the flashing of superheated
liquor. Hence, evaporation takes
place in the vapour body. Forced
circulation evaporator working
also creates a degree of agitation
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16. FORCED CIRCULATION EVAPORATOR
Advantages:
 High transfer coefficients obtained even with viscous solutions.
 Whenever we are dealing with concentration of highly viscous
and scale forming solutions forced circulation evaporators
prevents the scale formation on heating surfaces
 Residence times are low so that heat sensitive materials can be
used.
Disadvantage: The main disadvantage of forced circulation
evaporators is high pumping cost
Applications:
 These types of evaporators are widely used in industries for
salting, viscous and scale forming solutions
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17. MULTIPLE EFFECT EVAPORATOR
 The vapors, which contain latent heat, are generally discarded
in an evaporator, thereby wasting energy.
 But it can be used as steam supply to another unit operating
under lower pressure and temperature.
 The vapor from the second unit can be further used as a steam
supply to a third unit operating at a still lower pressure and
temperature.
 Each unit in such a series is called an effect and the method of
re-using the latent heat is called multiple-effect evaporation.
 In the case of multiple effect evaporators the economy
increases at the cost of capacity.
 Operating cost is same, but the capital cost, repair and
maintenance cost increases with increase in number of effects.
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18. Multiple effect evaporator
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19. THANK YOU.
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