in this ppt i descussed about evaporator.evaporation,Evaporation is the process by which an element or compound transitions from its liquid state to its gaseous state below the temperature at which it boils. types of Evaporators Open kettle or pan Horizontal tube natural circulation evaporator Vertical tube natural circulation evaporator Long tube vertical evaporator Falling film evaporator Forced circulation evaporator Open-pan solar evaporator

1. Communication skills-iii
Evaporator
Submitted by:-
Sumit Patel
20BPE137D
SoET
Submitted to:-
Mr.Arvind Kumar
PDEU

2. Introduction
evaporation, the process by which an element or compound transitions from its liquid state to its
gaseous state below the temperature at which it boils.
Example of evaporation
• Drying of clothes in the sun: The water present in the clothes when they are washed is removed by
the process of evaporation.
• Evaporation of acetone which is used for removing nail paint

3. Types of evaporator
1. Open kettle or pan
2. Horizontal tube natural circulation evaporator
3. Vertical tube natural circulation evaporator
4. Long tube vertical evaporator
5. Falling film evaporator
6. Forced circulation evaporator
7. Open-pan solar evaporator

4. Open kettle or pan
 Principle
The steam jacketed kettle or evaporating pan is an evaporator that can be used for
the bulk evaporation of water from aqueous liquids.
 Working
 Steam is supplied through the inlet.
 Steam gives out its heat to the contents and the
condensate leaves through the outlet.
 The rate of evaporation is fast in the initial
stages and decreases gradually as the liquid
gets concentrated.

5. Applications
 Concentrating aqueous liquids
 Concentrating thermo stable
liquors (ex. Liquorice extracts)
Advantage
 Evaporating pan is constructed both for small-
scale and large-scale operations.
 It is simple in construction and easy to operate,
clean, and maintains.
 Its cost of installation and maintenance is low.
 A wide variety of materials can be used for
construction such as copper, stainless steel, and
aluminum.
 Stirring of the contents and removal of the
product is easy.

6. Disadvantages
1. In evaporating pans, the heat economy is less. Hence. cost per unit
material production is more.
2. It is not suitable for heat-sensitive materials due to a long time of
exposure.
3. The heating area decreases as the product gets more concentrated.
4. As it is an open type, the vapor passes into the atmosphere, which can
lead to saturation of the atmosphere, slowing evaporation as well as
causing discomfort.
5. The boiling point of water cannot be reduced, since reduced pressure can
not be created in an open type of evaporator.

7. Horizontal tube natural circulation evaporator
Principle
Steam is passed through the horizontal tubes, which are
immersed in a pool of liquid to be evaporated. Heat
transfers through the tubes and the solvent evaporates.
Concentrated liquid is collected.
Working
Feed is introduced into the evaporator until the steam
compartment is immersed. The horizontal tubes
receives the heat and conduct it to the liquid. The feed
absorbes heat and solvent gets evaporated.
Concentrated liquid is collected.

8. advantage
 its relatively low cost per unit of heat surface.
 its extreme simplicity
 easy renewal of the heating surface
 its ability to carry a large volume of liquor in the body when finishing to a
definite density.
disadvantage
 it may be used only when rigorous boiling can be obtained with natural
circulation.
 its use should be avoided when scailing or salting liquids are involved.
application
horizontal-tube evaporators are widely used in the evaporator of sugar syrups,
Twitchell sweet water, tank water, beef extract, phosphoric acid, zinc chloride.

9. Vertical tube natural circulation evaporator
principle
Liquid is passed through the vertical tubes and
steam is supplied from outside tubes. Heat
transfer takes place through the tubes and the
liquids inside tube gets heated. The solvent
evaporates, vapor escapes from the top and
concentrated liquid is collected from bottom.
working
Steam is presented outside the tubes. The
condensate is gone through the comparing out
let and non dense gasses escape through the
vent.

10. The bolster is presented so as to keep up the fluids level somewhat over the
highest point of the tubes. The fluids in side the tubes is warmed by the steam and
starts to bubbles.
As the fluid bubbles it gushes up through the tubes and returns through the focal
down take. It set up a dissemination of hot fluid which upgrades the rate of
warmth exchange.
The vapor escapes through the top outlets. Steam is provided until required
grouping of the items is acquired. At long last the items can be pulled back from
the scrape the bottom let.
 Application
Vertical tube evaporator or short tube evaporator is utilized as a part of the
produce of the cascara remove, salts and scathing pop, and make of salts.

11.  Advantage
 Increases the heating surface 10-15 times than steam jacketed kettle.
 Fiery flow improves the rate of warmth exchange.
 Various units can be joined to got more proficient impact.
Disadvantage
 Liquid to be maintained above calandria.
 Complicated- increased installation cost.
 Pressure has to maintain.
 Cleaning and maintenance is difficult.

12. Long tube vertical evaporator
 working
In this evaporator, feed enters the bottom of the tubes, gets
heated by the condensing steam, starts to boil part way up
the tubes and a mixture of vapour and liquid issues from
the top of tubes and finally impinges at a high velocity on
a deflector. The deflector acts both as a primary separator
and a foam breaker. Some part of the separated liquid is
removed as a product and the remaining part is returned to
the bottom of the evaporator.
 application
This type of evaporator is widely used for handling of
foamy, frothy liquors.
It is used for the production of condensed milk and
concentrating a black liquor in the pulp and paper industry.

13.  advantage
 low cost
 large heating surface in one body
 low holdup
 small floor surface
 good heat transfer coefficients at all temperature differences
 disadvantage
 high head room
 generally unsuitable for salting and severely scaling liquids
 poor heat transfer coefficients of rising film at low temperature
differences

14. Falling film evaporator
 working
Feed enters from the top and flows down the
walls of the tube. The liquid becomes vapor and
forms small bubbles. They tend to fuse to form
layers of bubbles. Concentration takes place
during downward journey. Vapor and liquid are
separated at the bottom.
 application
Falling film evaporators are used extensively in
chemical process industry, food and paper
industry, dairy industry, Pharmaceuticals

15.  advantage
 Suitable for high viscous liquids
 Liquid hold up time is less
 Liquid is not overheated
 Highly acidic and corrosive feeds can be concentrated
 disadvantage
 Not for suspensions, salting and scaling liquids
 Poor feed distribution in tubes
 Feed ratio is high

16. Forced circulation evaporator
 Working
Feed is introduced through the liquor inlet.
Pump will force the liquid through the
calandria. Steam heats the liquid inside the
calandria. As it is under pressure in the tubes
the boiling point is elevated and no boiling
takes place. As the liquor leaves the tubes and
enters the body of the evaporator through the
tangential inlet there is a drop in pressure and
vapor flashes off from the superheated liquor.
The concentrated liquid is pumped out through
the product outlet and the vapor is collected
through the vapor outlet.

17.  Application
These evaporators are mainly used for thermolabile materials.
These can also be used in practice for the concentration of insulin and liver extracts.
 Advantage
In force circulation evaporator there is a rapid liquid movement due to high heat
transfer coefficient.
Salting, scaling and fouling are not possible due to force circulation.
This evaporator is suitable for themolabile substance because of rapid evaporation.
It is suitable for the viscous preparation because pumping mechanism is used.
 Disadvantage
The equipment is expensive because the power is required for the circulating the
liquids.
The hold up of liquids is high.

18. Open-pan solar evaporator
 Solar energy is used to evaporate the water
from the solution
 Application
Solar evaporators are used in contaminated water
purification, sea water desalination, electric
generation, steam sterilization, and fuel production.
 Advantage
 No more energy used
 cheap
 Disadvantage
 Low scale evaporator
 Takes longer time

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