Utilities used in textile industry

UTILITIES USED IN TEXTILE
INDUSTRY
UNIVERSITY OF KARACHI
CHEMICAL ENGINEERING
UTILITIES SECTION
Utilities section is the
department which supply
Electricity Steam Water
Compressed
air
UTILITY DEFINITION:
Utility provide services to industry
processes.
UTILITIES SECTION:
1.ELECTRICITY:

Electricity is used to run the machine in industry. It is power
source for machinery.
2.STEAM:

Steam is the vaporized state of water which contains heat
energy and transfer that energy into a variety of processes in
textile industry.

Boilers are the common installation in utility plants to
produce steam.
Applications in textile industry:

In textile industry Steam is used for fiber production,
weaving , dyeing , drying , printing, heating the equipment
and maintaining the temperature of system.

BOILER:
A boiler is basically a closed vessel into which water is heated
until the water is converted into steam at required pressure.
Classification of Boilers:
Boilers can be classified as follows:
1. According to relative position of water and hot gases
2. According to geometric orientation of boiler
3. According to location of furnace
4. According to method of water circulation
5. According to working pressure
6. According to mobility of boiler
7. According to number of tubes in the boiler
1.According to relative position of water and hot gases
a) Fire tube boilers; If the hot gases of combustion from the furnace pass
through the tubes and water is surrounding the tubes is called fire tube boilers.
b) Water tube boiler; If the water passes through the tubes and hot gases
surrounding the tubes is called water tube boiler.
Water Tube Boiler
Fire Tube Boilers
2.According to geometric orientation of boiler
a. Horizontal boiler; If the axis of boiler is horizontal is called Horizontal boiler.
b. Vertical boiler; If the axis of boiler is vertical then it is called vertical boiler.
c. Inclined boiler; If the axis of boiler is inclined then it is called inclined boiler.
3.According to location of furnace
d. Externally fired boilers; In this boiler the furnace is placed outside the boiler shell.
Generally water tube boilers are externally fired.
e. Internally fired boilers; In this boiler the furnace is placed inside the boiler shell.
Generally fire tube boilers are internally fired.
4.According to method of water circulation
f. Natural circulation boilers; In this boiler, water flow take place naturally, by

density difference of water. The flow of water and steam are set up due to density
difference resulting from difference in temperature.
g. Forced circulation boilers; In this boiler, water flow takes place by a pump.
5.According to working pressure
a. High pressure boiler; The working pressure of this boiler is higher
than 25 bar.
b. Medium pressure boiler; The range of working pressure of this
boiler is between 10 bar to 25 bar.
c. Low pressure boiler; The range of working pressure is between
3.5 to 10 bar.
6.According to mobility of boiler
d. Stationary boiler; This boiler cannot be moved easily from one
place to another place. This are used in power generation or
process heating in industries.
e. Mobile boiler; It is easily moved.
7.According to numbers of tubes in the boiler
f. Single tube boiler; This boiler having only one fire or water tube
for circulation of hot gases or water.
g. Multi-tube boiler ; This boiler having two or more fire or water
tubes for the circulation of hot gases or water.
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3.WATER :
The textile industry consumes large amount of water in its varied processing
operations.

In textile wet processing, water is used mainly for two purposes.
Firstly, as a solvent for processing chemicals and
Secondly , as a washing and rinsing medium.

The quantity of water required for textile processing varies from mill to mill

depending on fabric produce, process, equipment type and dyestuff.

The longer the processing sequences, the higher will be the quantity of
water required.

Bulk of the water is utilized in washing at the end of process.

In the mechanical processes of spinning and weaving, water consumed is
very small as compared to textile wet processing operations, where water is
used extensively.
Water consumption in Textile industry
COOLING TOWER:

A Cooling tower is a heat rejection device which
removes waste heat to the atmosphere through the
cooling of a water stream to a lower temperature.

Cooling towers use the evaporation of water toremove
process heat and cool the working fluid.

Cooling towers remove excess heat from large structures;
heat that is the product of machinery, processed material,
and mechanical processes.

The main purpose of cooling towers is to cool the
circulating water used in these structures.
Classification Of Cooling Tower

On the basis of air flow:
1.Natural draft

No external mean required to
force or draw air through the tower.
2.Mechanical draft
Uses power-driven fan motors
to force or draw air through the tower.
i. Induced draft
ii. Forced draft
.
On the basis of air-to-water flow
1.Cross flow
2.Counter flow
Mechanical draft:
It is divided into two types:
i) In induced draft cooling towers, the fan is
mounted at the top of the tower and is used to
"pull" air through the tower.
ii) In forced draft cooling towers, the fan is
mounted on the side of the tower and is used to
"push" air through the tower.
On the basis of air-to-water flow
i) In cross flow cooling towers, the air enters
the side of the tower and travels perpendicularly to
the water stream.
ii) In counter flow cooling towers, the air

enters at the bottom of the tower and travels up

in the opposite direction of the water stream.

The induced draft counter flow cooling tower is

probably the most common.
4.COMPRESSED AIR:

Compressed air is a form of stored energy that is used to
operate machinery, equipment, or processes.

Air compressor , used to produce compressed air.
Application In Textile Industry:

Compressed air is used mainly as a motive force to actuate
the process control valves and machines in a textile mill.

It is also used for loom jet weaving, spinning , texturizing.
AIR COMPRESSOR

A compressor is a machine that is used to increase the
pressure of a gas.
Compressor
Positive
displacement
Reciprocating Centrifugal
Axial
Dynamic
Rotary
Classification Of Air Compressor
1.Positive-displacement Compressor

In the positive-displacement type, a given quantity of air is
trapped in a compression chamber and the volume it
occupies is mechanically reduced, causing a corresponding

rise in pressure prior to discharge.
a. Reciprocating Compressor

A piston, driven through a crankshaft and connecting rod by
an electric motor, reduces the volume in the cylinder occupied
by the air or gas , compressing it to a higher pressure.
b. Rotary compressor

Rotary compressors have rotors in place of pistons and give
a continuous discharge.

The most common type of rotary compressor is screw-type.

Rotary screw compressor consists of two intermeshing rotors,
screw-rotors mesh, trapping air, and reducing the volume of
the air along the rotors to the air discharge point resulting in
increased pressure.
2.Dynamic Compressors

These compressors raise the pressure of air by imparting velocity energy and
converting it to pressure energy.
a. Centrifugal Compressor

The centrifugal-type is the most common and is widely used for industrial
compressed air.

A centrifugal air compressor has a
continuously flowing air stream
which has velocity energy, imparted
to it by an impeller.


Approximately one half of the
pressure energy is developed in the
impeller with the other half achieved
by converting the velocity energy to
pressure energy as the air speed is
reduced in a diffuser and volute.
B. Axial Compressors

Axial compressors consist of a rotor with multiple rows of
blades and a matching stator with rows of stationary
vanes.

The rotating blades impart velocity energy, primarily in an
axial plane. The stationary vanes then act as a diffuser to
convert the residual velocity energy into pressure energy.
BOILER WATER TREATMENT

The primary function of a boiler water treatment
program is to keep heat transfer surfaces free from
scale and deposition.

Boiler deposits are problematical, as they typically
contain undesirable levels of metal oxides, mineral
scale, sludge, or various combinations.

Boiler water treatment is used to remove suspended
solid , dissolved solid and dissolved gases.

The steps that are used to purify water before it goes to boiler

are:
1. Filtration to remove suspended solid
2. Reverse osmosis to remove dissolved solid
3. Deaeration to remove dissolved gasses
1.Carbon filter
.
A pressure vessel, filter bed of various sizes of gravel, sand,
and anthracite coal is usually sufficient to reduce suspended
solids to acceptable levels.
.
It remove some particles that cloud the water,
reduce nasty chlorine residue and can even help
to reduce odors, thus improving the general
taste and clarity of water.
2.Reverse osmosis

RO involves separating water from a
solution of dissolved solids by forcing the
water through a semi-permeable
membrane.
3.Deaerator

To reduce corrosive dissolved gases we use a deaerator.
Deaerators exploit the physical properties of temperature and
pressure to drive off dissolved gases.

The water introduced in a deaerator is sprayed in to the tank just
to remove the dissolved corrosive gasses( Hydrogen
(H2S) ,Carbon dioxide (CO2), Oxygen (O2))properly.


The water inside the deaeration tank is heated to 100 centigrade
temperature but the pressure is also exerted to stop boiling
phenomenon.

Once the gasses are forced out of solution they are vented off.

Now , treated water can be supplied into boiler.