The document outlines the operation and components of thermal power plants, focusing on pollution control methods and the Rankine cycle. It details the processes involved in converting heat energy from coal into electrical energy, including the roles of various parts like boilers, turbines, and condensers. Pollution control techniques such as scrubbers and selective non-catalytic reduction (SNCR) to manage emissions are also discussed.

1. 44th KVS JAWAHARLAL NEHRU SCIENCE,
MATHEMATICS AND ENVIRONMENT
EXHIBITION 2016-17
THEME : HEALTH
TITLE : POLLUTION CONTROL THERMAL POWER PLANT

2. Kendriya Vidyalaya A.F.S ARJANGARH NEW
DELHI

3. THERMAL POWER PLANT
POLLUTION CONTROL
BY:-HIMANSHU
ROLL NO :15

4. Thermal Power Station
Presented by :-
himanshu

5. Introduction
• In India 65% of total power is generated by theThermal Power Stations .
• In thermal generating stations coal, oil, natural gas etc. are employed as primary
sources of energy .
• A thermal power station basically work on the rankine cycle.
• Thermal power plant convert the heat energy of coal into electrical energy.
• Coal is burnt in a boiler which converts water into steam.
• The expansion of steam in turbine produces mechanical power which drives the
alternator coupled to the turbine.

6. Thermal Power Plant:
“A thermal power plant is a power plant in which the prime mover is
stream. Water is heated, turns into steam and spins a turbine which
drives an electrical generator. After it passes through the turbine, the
steam is condensed in a condenser and recycled to where it was heated,
this is known as a Rankine cycle.

7. Definition
A generating station which converts
heat energy of coal combustion into
electrical energy is known as thermal
power station.

9. parts
1.Coal Conveyor
Coal conveyor is a belt type arrangement that are used to move coal efficiently.
2.Pulverizer
Pulverizer increases the coal combustion efiiciency of coal.
3.Boiler (Furnace)
A boiler is a device used to create steam by applying heat energy to water.
4.Superheater
In a power plant, after the steam is conditioned by the drying equipment inside the
steam drum, it is piped from the upper drum area into tubes inside an area of the
furnace known as the super heater.
5.Economizer
Economizer are mechanical devices intended to reduce energy consumption, or to
perform another useful function like preheating a fluid.

10. 6.Reheator
Reheator added heat in the high-pressure steam.
7.Steam Turbine
A steam turbine is a mechanical device that extracts thermal energy from
pressurized steam, and converts it into rotary motion.
8.Generator
A device which convert mechanical energy into electrical energy is called generator.
9.Condenser
Condenser is a device or unit used to condense a substance from its gaseous to its
liquid state, typically by cooling it.
10.Deaerator
A deaerator is a device that is widely used for the removal of air and other dissolved
gases from the feed water to steam-generating boiler.

11. Coal Handling Plant
• The function of coal handling plant is automatic
feeding of coal to the boiler furnace.
• A thermal power plant burns enormous amounts of
coal.
• A 200MW plant may require around 2000 tons of coal
daily
• following are the process of plant-:
1. Unloading process
2. Feeding process
3. Screening process
4. Crushing process
5. Stacking process
6. Reclaiming process
7. Bunkering process

12. Pulverizing Plant
• In modern thermal power plant , coal is pulverized
• ground to dust like size and carried to the furnace in a
stream of hot air.
• Pulverizing is a means of exposing a large surface area
to the action of oxygen and consequently helping
combustion.
• Pulverizing mills are further classified as:
1. Contact mill
2. Ball mill
3. Impact mill

13. Draft System
• The circulation of air is caused by a
difference in pressure, known as
Draft.
• Draft is a differential pressure b/w
atmosphere and inside the boiler.
• It is necessary to cause the flow of
gases through boiler setting It may
be –
1. Natural draft
2. Mechanical draft

14. Boiler
•A boiler is a closed vessel in which water
under pressure, is converted into steam.
•It is one of the major components of a
thermal power plant Always designed to
absorb maximum amount of heat
released in the process of combustion
• Boilers are of two types-
1. Fire tube boiler
2.Water tube boiler

15. Ash Handling Plant
• The percentage of ash in coal varies from 5% in
good quality coal to about 40% in poor quality coal
Power plants generally use poor quality of coal .
• thus amount of ash produced by it is pretty large .
• A modern 2000MW plant produces about 5000 tons
of ash daily.
• The stations use some conveyor arrangement to
carry ash to dump sites directly or for carrying and
loading it to trucks and wagons which transport it to
the site of disposal

16. Steam Turbine
• A steam turbine converts heat energy of steam into
mechanical energy and drives the generator.
• It uses the principle that steam when issuing from a
small opening attains a high velocity.
• This velocity attained during expansion depends on the
initial and final heat content of the steam.
• This difference b/w initial and final heat content
represents the heat energy converted into kinetic
energy.
• These are of two types :-
1. Impulse turbine
2. Reaction turbine

17. Alternator
•Turbine and alternator are
mechanical coupled with each other.
•Alternator convert mechanical
energy of turbine into electrical
energy.
•The electrical output from the
alternator is delivered to the bus bar
through transformer.

18. Condenser
• Steam after rotating steam turbine comes to Condenser refers here
to the shell and tube heat exchanger installed at the outlet of every
steam turbine in Thermal power stations of utility companies
generally.
• These condensers are heat exchangers which convert steam from its
gaseous to its liquid state, also known as phase transition.
• In so doing, the latent heat of steam is given out inside the
condenser. Where water is in short supply an air cooled condenser is
often used.
• An air cooled condenser is however significantly more expensive and
cannot achieve as low a steam turbine backpressure (and therefore
less efficient) as a surface condenser.
• The purpose is to condense the outlet (or exhaust) steam from
steam turbine to obtain maximum efficiency and also to get the
condensed steam in the form of pure water, otherwise known as
condensate, back to steam generator or (boiler) as boiler feed water

19. Cooling Towers And Ponds
• A condenser needs huge quantity of water to
condense the steam .
• Most plants use a closed cooling system where warm
water coming from condenser is cooled and reused
• Small plants use spray ponds and medium and large
plants use cooling towers.
• Cooling tower is a steel or concrete hyperbolic
structure having a reservoir at the base
• For storage of cooled water Height of the cooling
tower may be 150 m or so and diameter at the base is
150 m

20. Feed Water Heater
• Advantages of heating water before feeding
back to the boiler:-
• Feed water heating improves overall plant
efficiency.
• The dissolved oxygen and carbon dioxide
which would otherwise cause boiler corrosion
are removed in feed water heater
• Thermal quantity of steam produced by the
boiler is increased.
• Some other impurities carried by the steam
and condensate, due to corrosion of boiler and
condenser are precipitated outside the boiler.

21. Economizer
• Flue gases coming out of the boiler
carry lot of heat.
• An economizer extracts a part of
this heat from flue gases and uses it
for heating feed water.
• This use of economizer results in
saving coal consumption and higher
boiler efficiency

22. Super heater
• Super heater is a component of a steam-
generating unit in which steam, after it has
left the boiler drum, is heated above its
saturation temperature.
• The super heater may consist of one or more
stages of tube banks arranged to effectively
transfer heat from the products of
combustion.
• Super heaters are classified as convection ,
radiant or combination of these.

23. Reheater
• Some of the heat of superheated steam is used to rotate the
turbine where it loses some of its energy.
• Reheater is also steam boiler component in which heat is
added to this intermediate-pressure steam, which has given
up some of its energy in expansion through the high-pressure
turbine.
• The steam after reheating is used to rotate the second steam
turbine where the heat is converted to mechanical energy.
• This mechanical energy is used to run the alternator, which is
coupled to turbine , there by generating electrical energy.

24. Air Preheater
• An air pre heater increases the temperature of
air supplied for coal burning
• And it driven from the flue gases.
• Air is drown from the atmosphere by the force of
draft fan.
• Air preheaters may be of three types
1. Plate type
2. Tubular type
3. Regenerative type

25. function
STAGE 1
Coal arriving by train can be stocked for later use or taken straight to the coal
bunkers.
 Coal is prepared for use by crushing the rough coal to pieces less than 2 inch (5
cm in size). Crushing the coal into a fine powder makes easirer to burn it more
completely.
Coal mills grind the larger of 2 inch pieces to face powder and mixed them with
primary combustion air which transports the coal to the furnace and preheats
the coal to drive off excess moisture content.
By pulverizing the coal combustion efficiency of coal increases.
Conveyor Pulverized mill

26. sTAGE 2
Pulverized coal is burnt to produce steam.
Water from the feed pump, after pre-heating enters the
boiler. This water may be obtained from a nearby river or
lake. The condensed water from the cooling tower is re-
used.
The heated or vapourized fluid exits the boiler for use in
various processes and heating applications.

27. STAGE 3
The steam produced in the boiler,
goes to the steam drum and is then
piped to super-heaters where it is
heated above saturation temperature.
At this point steam is now turned into
a very powerful source of energy.
This rotates the turbine.

28. STAGE 4
Flue gases coming out of the boiler carry
a lot of heat. An economizer extracts a
part of this heat from flue gases and use
it for heating feed water.
This use of economizer result in saving
coal consumption and higher boiler
efficiency.

29. STAGE 5
Reheaters is also a steam boiler in which heat is added
to this high-pressure steam. Which has given up some of
its energy in expansion through the intermediate-
pressure turbine.
The steam after reheating is used to rotate the the
second steam turbine where the heat is converted to
mechanical energy.
This mechanical energy is used to run the generator,
which is coupled to the turbine, there by generating
electrical energy.

30. STAGE 6
The turbine generator consists of a series of
steam turbines interconnected to each other
and a generator on a common shaft.
There is a high pressure at one end , follower
by an intermediate pressure turbine. A low
pressure turbines, and the generator.
As steam moves through the system, it losses
pressure and thermal energy and expands in
volume, requiring increasing diameter and
longer blades at each succeeding to extract
the remaining energy.

31. Stage 7
Steam after rotating steam turbine comes to the condenser.
The purpose of condenser is to condense the outlet steam from
steam turbine to get the condensed steam in the form of pure
water.
This water is then pumped back to boiler.

32. STAGe 8
A steam generating boiler requires that the boiler feed
water should be devoid of air and other dissolved
gases,particularly corrosive ones.
In order to avoid corrosion of the metal power station
uses a Deaerator, for the removal of air and other
dissolved gases from the boiler feed water.
A deaerator has a vertical. Domed deaeration section
mounted on top of a horizontal cylindrical vessel which
seves as a deaerated boiler feed water
storage tank.

33. STAGE 9
The enormous pressure of the steam pushing against
a series of giant turbine blades turns the turbine shaft.
The turbine shaft is connected to the shaft of
the generator, where magnets spin within wire coils to
produce electricity.
Electricity is send through power grid lines and then
travelled to substations located in towns.

34. Video on working of coal fired power plant

35. HOW TO CONTROL POLLUTION
PRODUCED BY THERMAL
POWERPLANTS

36. TYPES OF POLLUTION CONTROL METHODS ADOPTED IN THERMAL
POWERPLANTS

37. Power Plant Pollution Control
What is being
Removed by
The electrostatic
Precipitator?
By the wet
Scrubber?

38. pollution control devices

43. ASH WATER RECYCLING SYSTEM

45. How do coal-fired power plant scrubbers
work?
If coal were pure carbon, then the only thing we would have to worry about at
coal-fired power plants is the carbon dioxide formed when coal burns.
Unfortunately, coal often contains other chemicals. Sulfur is one common
element found in coal. When burned, the sulfur in coal turns into sulfur dioxide.
When sulfur dioxide mixes with moisture in clouds, it creates acid rain
Scrubbers help to remove most of the sulfur oxides from the smoke stack
exhaust of a power plant. The smoke from the burning coal first goes through a
particulate filter to remove soot and ashThen it enters a scrubber. In the
scrubber, there is a water spray that produces a cloud of fine water droplets.
The water is mixed with crushed limestone, which reacts with the sulfur and
pulls it out of the exhaust.
The unexpected side effect is that the calcium in the limestone plus the sulfur
form gypsum (CaSO4-2H2O). Gypsum is best known as the material
inside gypsum wallboard.

46. Selective Non-Catalytic Reduction (SNCR)
It is a method to reduce the level of nitrogen
oxides (NOx) emissions in conventional
combustion plants that burn coal, biomass and
waste. Cement plants, waste incinerators and
waste-to-energy plants that need to reduce
their NOx emissions will often choose SNCR
as an efficient, low-cost NOx reduction system.

47. Why choose SNCR?
Selective non-catalytic reduction
involves only a fraction of the
investment cost compared to SCR
technology. It can, in many cases,
also be installed without the need of
expensive downtime which is
required for installing catalyst,
injection grids and mixers required
for SCR.

48. Video on SNCR

49. CHEMICAL REACTIONS INVOLVED IN SCRUBBING
Ca(OH)2(s) + SO2(g) → CaSO3(s) + H2O(l)
CaSO3(aq) + 2H2O(l) + ½O2(g) → CaSO4 · 2H2O(s)
CHEMICAL REACTIONS INVOLVED IN S.N.C.R
4 NO + 4 NH3 + O2 -> 4 N2 + 6 H2O

50. BIBLOGRAPHY/REFERENCE
• www.brainstuffshow.com
• www.yara.us
• www.firstenergycorp.com
• https://en.wikipedia.org/wiki/FirstEnergy
• www.myclassbook.org
• BY READING BOOKS
• COLLECTING ARTICLE FROM NEWSPAPER