STEAM TURBINE
By group :-
Ruqaya Raad
Abbas Talib
Zahraa Awad
Huda Ahmed
Hala Adil
Naba'a Tariq
Dr. Aws AL-Akam
INTRODUCTION TO STEAM TURBINES
Steam turbines are used in all of our major coal fired
power stations to drive the generators or alternators,
which produce electricity. The turbines themselves
are driven by steam generated in ‘Boilers‘ or ‘Steam
Generators‘ as they are sometimes called.
Energy in the steam after it leaves the boiler is
converted into rotational energy as it passes through
the turbine. The turbine normally consists of several
stages with each stage consisting of a stationary
blade (or nozzle) and a rotating blade. Stationary
blades convert the potential energy of the steam
(temperature and pressure) into kinetic energy
(velocity) and direct the flow onto the rotating
blades. The rotating blades convert the kinetic
energy into forces, caused by pressure drop, which
results in the rotation of the turbine shaft.
STEAM TURBINE PART
The main parts of a steam turbine are :
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the rotor that carries the blading to convert the
thermal energy of the steam into the rotary motion
of the shaft
the casing, inside of which the rotor turns, that
serves as a pressure vessel for containing the steam
(it also accommodates fixed nozzle passages or
stator vanes through which the steam is
accelerated before being directed against and
through the rotor blading)
the speed-regulating mechanism
the support system, which includes the lubrication
STEAM TURBINE PRINCIPLE
In simple terms, a steam turbine works by using a
heat source (gas, coal, nuclear, solar) to heat
water to extremely high temperatures until it is
converted into steam. As that steam flows past a
turbine’s spinning blades, the steam expands
and cools. The potential energy of the steam is
thus turned into kinetic energy in the rotating
turbine’s blades. Because steam turbines
generate rotary motion, they’re particularly
suited for driving electrical generators for
electrical power generation. The turbines are
connected to a generator with an axle, which in
turn produces energy via a magnetic field that
produces an electric current.
TYPES OF STEAM TURBINE
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The two types of steam turbines most widely
used are the backpressure and the extractioncondensing types .The choice between
backpressure turbine and extractioncondensing turbine depends mainly on the
quantities of power and heat, quality of heat,
and economic factors. The extraction points of
steam from the turbine could be more than
one, depending on the temperature levels of
heat required by the processes.
ADVANTAGES
1.
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S Ability to utilize high pressure and high
temperature steam.
High efficiency.
High rotational speed.
High capacity/weight ratio.
Smooth, nearly vibration-free operation.
No internal lubrication.Soil free exhaust
steam.
Can be built in small or very large units (up to
1200 MW).
DISADVANTAGES
Although approximately 90% of all electricity
generation in the world is by use of steam
turbines, they have also some disadvantages :1. Relatively high overnight cost
2. Steam turbines are less efficient than
reciprocating engines at part load operation.
3. They have longer startup than gas turbines
and surely than reciprocating engines.
4. Less responsive to changes in power demand
compared with gas turbines and with
reciprocating engines.
APPLICATION
Steam turbines are part of various industries, from medium
to large, and include dozens of institutional applications:1.
2.
3.
4.
Chemical Industry: Providing heat and electricity to
drive various processes In the chemical and
pharmaceutical industries, steam turbines are
integrated into the power production process.
Waste plants: Steam turbines help generate the energy
needed to harness energy from waste.
Oil and Gas: Steam turbines are used as a pump or
compressor motor, and support dozens of processes in
the oil and gas industry
Sugar Mills: Steam turbines offer high levels of efficiency
and sustainable operations, and are used to produce
green carbon dioxide energy from bagasse.
THANK YOU