1. Role of Compressed Air
System in Textile Industries
UNIVERSITY OF KARACHI
CHEMICAL ENGINEERING
AELYA SHAH

2. Agenda
 Introduction
 Use of Compressed Air in Textile Industry
 Applications
 Compressed Air System
 Types of Compressor
 Compressor used in Textile Industry
 Optimization of Air System
 Minimizing Compressed Air Cost

3. Introduction
 Compressed air, also referred to as the
"4th
Utility" (after electricity, water & steam) is
one of the major energy consumption utility in
any industry.
 Various estimates indicate that about 4,000-
5,000 MW is consumed nation wide by the
compressors and its related accessories &
support systems.

4.  It is a well-known fact that of the life
cycle cost of any compressor, 85-90% is
towards energy and only 10-15% towards
initial investment & maintenance.

5.  Hence, the design and selection of the right
compressor assumes great significance while
setting up your air system. It is very important on
the part of each one of us using compressed air to
understand a simple fact that "Air is free but
compressed air is not!"

6. Use of Compressed Air in
Textile Industry
In Textile manufacturing units, generally
following Compressed air powered pneumatic
systems are used:
 Spinning machine (for control purpose through
valves and cylinders)
 Loom Jet Weaving (for the insertion of weft).
 Winding machine (for the purpose of splicing of
yarn)

7. Use of Compressed Air in
Textile Industry
 Stacking Device
 Printing machines
 Thread Detector
 Sewing Machine

8.  Texturising
 Automated
Equipment
 Agitating Liquids
 Cleaning
 Pneumatic control
and actuators
 System Cooling
 Clamping
 Blowing out
residual / dust
material
 Sewing Needle
 Conveying
Applications

9. Compressed Air System
The compressed air system mainly consists of:
•Supply side
•Distribution &
•Demand side

10.  Compressed air systems consist of a supply side,
which includes compressors and air treatment.
 and a demand side, which includes distribution
and storage systems and end-use equipment.
 A properly managed supply side will result in
clean, dry, stable air being delivered at the
appropriate pressure in a dependable, cost-effective
manner.
 A properly managed demand side minimizes
wasted air and uses compressed air for
appropriate applications.
Compressed Air System

11. compressed air sub system
As such the compressed air system has following
six major sub systems
•Air compressors
•Controls
•Air Quality
•Storage
•Distribution
•Demand (consumption)

13.  The compressed air generated by compressor
is stored in the Air-receiver of sufficient capacity
to smoothen fluctuations in the supply of
compressed air vis-a-vis demand from
individual consumption points (machines).
The air receiver helps also in cooling of air and
this facilitates removal of much of the moisture
in the air which is harmful for the pneumatic
system.
Air-receiver

14.  For large users/bigger compressors air dryer
units are provided.
 The air dryer units of two types are
normally employed in the mills.
1.heatless dryer
2.refrigerated air dryer.
Air-dryer

15.  Although, the refrigerated air dryer has
higher initial cost, it has less operational cost
than the heatless type. This is because in
heatless dryer about 10-12% of compressed
air is lost in purging thereby wasting costly
electrical energy.
 The air dryer helps in making the
compressed air almost 100% dry – which is
essential for some machines such as Air jet
looms
Air-dryer

16.  As regards air distribution network, it
should be ensured that pressure drop should
not be more than 0.5 kg/cm2in the longest
line.
 The pipe sizes are to be decided based on
this consideration. Also the pipe lines should
be of minimum length with less bends and
fittings.
 This will ensure minimum wastage of
electrical power.
Air distribution

17.  For the proper and trouble free operation
of pneumatic systems provided for the
machines, it is essential to ensure filteration,
pressure regulation and lubrication of the
compressed air.
 The filteration is ensured by providing
filters in the pipe line after the air receiver.
These can remove dust particles upto 5
micron size.
Air filter

18.  Pressure regulation i.e. maintaining the
desired air pressure for the machines used
is achieved by the use of air pressure
regulator.
Pressure regulation

19.  For reducing friction and wear
and tear and preventing corrosion,
proper lubrication of compressed
air is necessary. This is achieved by
the ‘oil-fog’ air line lubricator.
Lubrication

20. TYPES OF COMPRESSOR:

21. TYPES OF COMPRESSOR
 Air compressors are mainly classified in two
types based on their construction & operation:
1. Positive displacement (Reciprocating &
Rotary compressors)
2.Dynamic type (Centrifugal & Axial flow
compressors)

22. Positive-Displacement
Compressors
 In the positive-displacement type, a given
quantity of air or gas is trapped in a
compression chamber and the volume which
it occupies is mechanically reduced, causing
a corresponding rise in pressure prior to
discharge. At constant speed, the air flow
remains essentially constant with variations
in discharge pressure.

23. Reciprocating compressors
 It work like bicycle
pumps. 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.

24.  Double-acting reciprocating compressors
are generally water-cooled and with multi-
stage versions are usually considered to be the
most efficient air compressors (100 hp to 250
hp). These however, come with high initial &
installation costs and higher maintenance as
well.
 Single-acting reciprocating compressors are
generally air-cooled and available in the
smaller hp sizes (1 hp to 50 hp). However, such
compressors are generally less efficient than
the other types.

25. Screw compressors
 Screw compressors are available as oil-
flooded (lubricated) single or multistage
(generally from 15 hp to 500 hp) but have lower
operating efficiencies at part-loads and also
high unload power, which could become the key
factors in reducing your operating efficiencies.
However, incorporating VFD (variable
frequency drive) or HPM motor (hybrid
permanent magnet) would make these
compressors efficient throughout the operating
range.

26.  Advantages of the rotary screw compressor
include smooth, pulse-free air output in a
compact size with high output volume over a
long life.

27. Dynamic compressors
 Dynamic compressors impart velocity energy
to continuously flowing air or gas by means of
impellers rotating at very high speeds. The
velocity energy is changed into pressure energy
both by the impellers and the discharge volutes
or diffusers.
 In the centrifugal-type dynamic
compressors, the shape of the impeller blades
determines the relationship between air flow
and the pressure (or head) generated.

28. Centrifugal compressors
 A centrifugal air compressor has a
continuously flowing air stream which has
velocity energy, or kinetic energy, imparted to it
by an impeller, or impellers, which rotate at
speeds that can exceed 50,000 revolutions per
minute (rpm).
 Three stage centrifugal compressors
available in the market would give much higher
efficiencies generally 10-15% more than the two
stage positive displacement types.

29.  Moreover, features like 100% oil-free air,
constant pressure, high turndown abilities with
good part-load efficiencies, nil wear & tear,
much lower maintenance costs have made this
compressor very popular with all users.
 These are available
from 250 hp to 5,000 hp
and upward as well.

30. Compressor used in Textile
Industry:
 Reciprocating type of compressors were normally in
use in the textile industry.
 However, of late screw compressors are being
preferred as these are more energy efficient as compared
to reciprocating compressors.
For very high capacity requirements centrifugal
compressors are used. In fact, for many large textile
units who have been using positive displacement
technology for the last 5-10 years or above can ideally
look to incorporate the centrifugal technology, which will
have payback of less than 2 years in most cases.

31. Capacity range of air
compressors
The compressor capacity is stated in terms of cfm i.e. cubic
feet per minute of air (being compressed or free air
delivery). Capacity range of air compressors normally used
in the industry is as follows:
Type of Air Compressor Capacity Range (cfm)
Reciprocating Compressor, Single
Stage
Upto 50 cfm
Reciprocating, Two Stage 50-600 cfm
Screw Compressors 150-2500cfm
Centrifugal Compressors 2000-4000cfm

32. Optimization of Air System
The six steps to optimize an air system are
following.
Demand Side
1. Establish your correct air needs for the points-
of-use (Flow & Pressure)
Distribution Side
2. Establish the leakage in your system and
proactively manage the same
3. Analyse the System Capacitance & optimize
the same.

33. 4. Track the pressure profiles across the plant
to match the supply & demand and also
minimise the pressure drops
Supply Side
5. Evaluate the health of the compressors and
the support systems
6. Optimise the controls to match the system
dynamics
Optimization of Air System

34. Minimizing Compressed Air
Cost
 Compressed air cost can be minimize
broadly in two ways
1. By minimizing wasteful consumption of
compressed air i.e. by preventing
compressed air leakages.
2. By improving the efficiency of
compressors.