Basic components of power plant

1. Basic Components of Power
Plant
Group Members:
HassanIlyas 19013323-030
HassanShabbir 19013323-015
AliAbbas 19013323-001

2. Compressors
Compressor is the mechanical equipment which is used toincrease the
pressure of the air by reducing its volume. Theyare somehow similar to
the pumps both increase thepressure and both transport the fluid
through their pipes.

3. Types of compressor on the basis

4. a) Positive Displacement:
The compressors which compresses the air by the displacement of
amechanical linkage reducing the volume.
1. Reciporcating Compressor:
These compressors use the piston driven by the crankshaft. They can
beeither stationary or portable. It can be single staged or multistage
and canbe driven by the electric motors or internal combustion engines
as well.They are made for intermittent duty.

5. Reciprocating Types
• Single Acting Compressor:
Compressor which compresses the air in one direction only having
singlepiston.
• Double Acting Compressor:
It also has just one cylinder but is pipe up such way that its capable of
takingin discharging fluids from both ends and hence increases the
efficiency.
• Multistage Compressors:
Multistage compressor is simply the compression of the fluid in two or
morecylinders instead of one cylinder.

6. 2. Rotary Compressor
These compressors does not have any reciprocating motion in fact it
hasrotating motion with screws, scrolls, and vanes rotating along side a
shaft.
• Screw compressors:
A type of gas compressor that uses a rotary type positive
displacement.They are used in place of piston comp where large
volume of aircompression is needed and without intermittence. It has a
pair of helicalrotors where it traps air, as the rotor rotates in the
cylinder. The malerotor and female rotor are being built inside the
cylinder for compression.They are generally used in large industrial
areas.

7. • Scroll/Spiral Compressors:
A scroll compressor has one fixed scroll which remains stationary all
thetime with another orbiting scroll which rotates through the use of
swinglink. When this happens, the pockets of the air are pushed slowly
to thecenter of scrolls due to the movement of the rotating scroll
causing thereduction of the volume and hence increase in the pressure.
• Vane Compressor:
Rotary vane compressor consists of a rotor with a number of blades
inserted inradial slots in the rotor. As the rotor turns, blades slide in
and out of the slotskeeping contact with the outer wall of the housing.
Thus, a series of increasing anddecreasing volumes is created by the
rotating blades. They can be either stationaryor portable, can be single
staged or multistage driven by electric motors.

8. b) Rota Dynamic Compressors
Compression is carried out by a rotating element which is
impartingvelocity to the flowing air or gas and hence developed
desiredpressure, and compression is achieved by the dynamic action of
rotor.
Two major types of dynamic compressors
• Centrifugal Compressors
• Axial compressors

9. • Centrifuge Compressors:
They use a rotating disk or impeller in a shaped housing to force the
gasto the rim of the impeller, increasing the velocity. A diffuser or
divergentduct converts the velocity energy to pressure energy.
Application:
Used in stationary service in industries such as oil refineries, chemical
andnatural gas processing plants, small gas turbine engines also can be
usedin l.C engines as supercharger and turbocharger.

10. • Axial Flow Compressors:
Axial flow compressors are dynamic compression that use arrays of
fanlike airfoils to progressively compress a fluid. They are used where
highflow rates or a compact designs are required.The arrays of airfoils
are set in rows, usually as pairs: one rotating and onestationary. These
rotating airfoils are known as blades transport andcompress the
fluidThese compressors can have high efficiency of up to 90%.

11. Cooling Tower
A cooling tower is a heat rejection device. It works by bringing air
and water into contact to cool the water and release unwanted
heat into the atmosphere. Cooling towers are useful in industrial
processes because industrial equipment tends to generate
tremendous amounts of heat. Facilities need reliable ways to
dissipate that heat to keep their working environments cool and
reduce the risk of breakdowns and fire.

12. Types of cooling tower:
1. Natural Draft:
Natural draft cooling towers utilize no mechanical drivers or fans
to create air flow through the cooling tower. This cooling tower
takes advantage of the difference in ambient air densities below
and above the tower. Air flow is created as the denser air at the
bottom of the tower travels to a lower pressure area above the
tower. These towers are inexpensive but can only be installed
outdoors. Also, these towers have lower reliability as they are
more affected by ambient wind and temperature changes.

13. 2. Mechanical Draft:
These towers use either single or multiple fans to generate air
flow through the tower. Mechanical draft cooling towers are more
reliable and stable than natural draft towers since air flow can be
manipulated according to the cooling load required. Mechanical
draft cooling towers can be further classified as forced or induced
draft.

14. • Forced Draft:
This type of cooling tower uses fans or blowers to force air into
the cooling tower. Air flow has high entrance velocity as it is being
forced by the blower. As it passes through the tower, air flow
slows down. Thus, performance is less stable compared to
induced draft towers due to recirculation. Forced draft cooling
towers are used in indoor applications where high static pressure
is a concern.

15. • Induced Draft:
These have their fans located at the top that draws (or induces)
air from the air intake louvers at the bottom or sides of the tower.
Contrary to forced draft cooling towers, this arrangement has low
entrance and high exit velocity, which results in reduced
recirculation. These types of cooling towers are widely used in
industrial plants requiring stable performance.

16. 3. Hybrid Draft:
Its operation is the same as natural draft towers, but equipped
with fans for air flow. Hence, they are also referred to as fan-
assisted natural draft cooling towers. The fans in this setup
have lower horsepower compared to forced and induced draft
fans. Because of the additional draft, there is no need to
construct a tall tower which may be economically impractical
for a given application

17. Turbines
A turbine is rotating part which converts kinetic energy of working fluid into
useful mechanical energy or electrical energy.
Types of turbine:
The 4 types of turbines are-
1. Water turbines
2. Steam turbines
3. Gas turbines
4. Wind turbines

18. 1. Water Turbines
This type of turbines is used in hydroelectric powerplants that have
water as their working fluid.First of all, millions of litres of water is
collected in the dam. More the height of the dam, the more pressure.
The highly pressurized water is then made to flow via a large pipe
called a penstock.The turbine is located at the end of the penstock
from where the pressurized water strikes the blades of the turbine at
high velocity making it rotate. This turbine is connected to a generator
which generates electricity.
Water turbines are classified into 2 types-
• Impulse type
• Reaction type

19. • Impulse Turbines:
Impulse turbines basically work on Newton’s 2nd law.
In impulse turbines, the number of elliptical half-sized buckets are
fitted instead of blades on the rotor hub. When water strikes the
buckets at high speed, the rotor starts rotating. In short, the
kinetic energy of water gets converted into rotational mechanical
energy!
Thus electricity is generated when one end of the turbine shaft is
connected to the generator !
Example – Pelton turbine

20. • Reaction Turbines:
The turbine blades or the impeller blades are designed in such a way that a
force is generated on one side when water flows through it just like an airfoil.
The force produced by an airfoil is responsible for the lift of an airplane.
Similarly here, that force makes the blades rotate.
Example – Kaplan turbine
Different types of turbines have their own ideal operating conditions. For eg.

21. • Pelton turbines are preferred where a low discharge rate can be obtained &
high head(80-1600m) is available.
• Kaplan turbines require a high discharge rate along with low or medium
head(2-70m).
• Francis turbine work on medium flow rate & medium head. Francis turbine is
a combination of impulse & reaction turbines. Francis turbines are the most
widely used turbines because they offer the highest efficiency & could also
work in a wide range of operating conditions.

22. 2. Steam Turbines
Steam Turbines are used in nuclear & thermal powerplants where water is
heated to form steam & then flowed through turbines to produce electricity. Alike
water turbines, steam turbines are also classified into impulse & reaction types
but the arrangement & design is different. All the modern steam turbines are a
combination of impulse & reaction type.

23. 3. Gas Turbines
Gas turbines are not only used in powerplants for generating
electricity but also for propelling airplanes & helicopters. Gas
turbines as a whole system has an axial compressor at the inlet.
These are sets of rotating blades which suck a huge amount of
air & compress it which also increases the temperature. This air
is then supplied to the combustion chamber. Fuel is added into
the combustion chamber & ignitor ignites the fuel. Thus a large
amount of exhaust gases are produced which are made to flow
through turbines.

24. 4. Wind Turbines
Wind turbines are a boon to mankind- affordable, clean & sustainable!
The working of wind turbine is same as other turbines. The rotor has 3
blades & are designed in such a way that when wind flows straight
through them, they start rotating. The only problem here is wind
turbines rotate at a very low RPM. The low RPM doesn’t produce
electricity of required frequency & that is why we require a gearbox
which increases the speed of the shaft. The output shaft is then
connected to the generator.
The 3 primary types of wind turbines are –
• Horizontal-axis wind turbines (HAWT)
• Savonius vertical-axis
wind turbine (Savonius VAWT)
• Darrieus vertical-axis
wind turbine (Darrieus VAWT)