4. INTRODUCTION
HINDALCO-HIRAKUD POWER is a coal based Thermal
Power plant which is located at Hirakud, Dist: Sambalpur.
The nearest Railway station is Sambalpur Junction which is
about 12 kms from plant.
It’s a CPP (Captive Power Plant) and it has basically 2
branches. One is Power generation and another is Smelter.
This power plant generates its own power and utilises for
smelting and auxiliary consumption. In addition to that it
exports some power to grid.
5. DESCRIPTION
This power plant
has 5 units. It is
capable of
generating 467.5
MW.
As it is a coal
based thermal
power plant it uses
coal as its fuel for
boiler.
It collects coal
from its own mine
i.e. Talabira mines
which is at a
distance 60kms
from plant. The
daily input of coal
is 7KT/day.
6. THE COAL BASED THERMAL POWER
PLANT COMPRISES OF FOLLOWING
UNITS
Steam generator
Steam turbine
Coal handling
system
Ash handling
System
Air cooled
Condenser
ESP
Power plant stack
Fuel system
Utilities & Services
7. General Requirement
details:
Water requirement:
900m3/hr.
Source: Reservoir,
Hirakud
Environmental
Aspects:
Use of limestone to
reduce emission
Use of environmental
friendly CFBC
Technology
Use of Air cooled
condenser to reduce
coal consumption
ESP to minimize the
emission of
particulate matter
Fire protection
system
Dust Suppression
system
8. BRIEF DISCUSSION ABOUT
POWER PLANT PROFILE
Hindalco-Hirakud power consists of 5 units.
Means here 5 turbines and 13 boilers are present.
U # 1 is capable of producing 67.5MW power.
And two boilers are connected to it.
U # 2, U # 3, U # 4 have the capacity of
producing 100MW power and 3 boilers are
assisted to each unit.
U # 5 has the capacity of producing 100MW
power & two boilers are assisted.
Hence the plant is capable of producing 467.5
MW. As per the demand of smelter it’s producing
the power.
9.
10. There are three basic circuits in a
boiler:
(a) water & steam that includes the boiler
feed pump (BFP).
(b) coal & fly ash that includes the drag
chain conveyor (DCC).
(c) air & flue gas that includes the ID fan
PA fan & SA fan.
Two main terms related to boiler are:
(a) mounting that includes safety valve, pressure
gauge, level probe etc..
(b) accessories that includes ID fan, PA fan, SA
fan, DCC, BFP etc..
11. WATER CIRCUIT
Boiler feed pump (BFP) (around 210oc)
ECO 01 ECO 02 (250oc)
Evaporator Drum Screen
(510+- 5 oc)
(300 oc) Super heater 01
SH 01 Downcomer SH 02 SH 03
Waterfall TG
13. AIR
CIRCUIT...
PA fan
Furnace
TA fan SA fan
APH
Electrostatic
Precipitator(ESP)
ID fan
Chimney
14. FUEL PROCESSING PARAMETERS:
COAL MINE COAL YARD
PRIMARY CRUSHER SECONDARY
CRUSHER FEED COAL
CONVEYING COAL BUNKERS
BOILERS
The fuels burnt in
these boilers
include low-grade
coal, biomass,
sludge, waste
plastics, waste
tires.
15. WHAT IS A BOILER...?
According to IBR
1923 boiler is a
closed vessel used
for generation of
steam for power
generation under
temperature and
pressure by
combustion of fuel
and air.
Boiler is suspended
from the top on
four columns and
kept free from the
bottom side for free
expansion on
downward direction.
16. SCHEMATIC
DIAGRAM OF
BOILER...
Feed water is fed to the boiler
drum through the economiser.
Water then enters in bottom
ring header through six numbers
of down comers.
17. PROCESS OF COMBUSTION...
There are nozzles
on the sand bed
through which
primary air (pa)
enters that helps
in fluidising the
sand and heats it
upto 510 degree
celcius.
The oil is
introduced
through the oil
gun in the hgg
area and coal
through drag
chain conveyor.
18. The coal also gets fluidised and the temperature rises as
combustion ocurrs.
The heat energy developed by combustion of coal in furnace
is utilized for the evaporation of water in water walls.
As the density of steam is lower
than water ,this water steam mixture enters in boiler
drum without help of any pump. This is called natural
circulation
19. The main
mechanism
behind it is CFBC
technology i.e.,
circulating
fluidised bed
combustion.
It utilises the
fluidized bed
principle in
which crushed
(6-12 mm size)
fuel and
limestone are
injected into the
furnace.
20. The particles
are suspended
in stream of
upwardly
flowing air (60
– 70% of the
total air) which
enters the
bottom of the
furnace through
air distribution
nozzle.
The fluidizing
velocity in
circulating bed
ranges from
3.7 to 9 m/s.
21. In boiler drum steam is separated from the mixture.
Steam that comes out of boiler is called saturated steam.
This saturated steam is then passed through number of
superheaters.
22. When coal is burned in the boiler furnace, hot flue gases pass
through the first pass and then to the second pass to the exit of
boiler. Economiser and primary superheaters are placed in
second pass one above the other, economiser being placed at the
exit.
The temp. of the flue gases in the combustion zone is 1110 oc.
The temp. of flue gas gradually decreases to 400 oc when it
leaves second pass.
The flue gas then goes through air pre heaters where its temp.
Drops down to 140oc.
23. Bottom ash falls in the bottom hopper and after crushing it
is transferred to ash handling plant .
Fly ash alongwith the flue gases goes through ESP where fine
ash is taken out and send to the ash handling plant for
further processing to the ash bunds.
Boiler drum, superheater and reheaters are fitted with safety
valves for safety against the high pressures of the steam.
24. WHAT IS AN
ECONOMIZER?
An economiser is a
mechanical device
which is used as a heat
exchanger by
preheating a fluid to
reduce energy
consumption.
In a steam boiler, it is a
heat ex-changer device
that heats up fluids or
recovers residual heat
from the combustion
product i.e. flue gases in
thermal power plant
before being released
through the chimney.
25. WORKING PRINCIPLE OF
AN ECONOMISER...
The recovered
heat is in turn
used to
preheat the
boiler feed
water, that
will eventually
be converted
to super-
heated steam.
Thus, saving
on fuel
consumption
and
economising
the process to
a large extent
26. ADVANTAGES AND BENEFITS OF
ECONOMIZER
It recovers more heat of flue gases which
normal air pre-heater can not do.
Due increase in fuel prices, all power plants
are facing pressure for increasing boiler
efficiency. So by using economizer, this
pressure can be minimized.
Power plants where it is not used, large
quantity of water is required to cool the flue
gas before desulphurization which is
minimized by using economizers.
The efficiency of power plant reduced when
steam air pre-heater required steam.
27. WHAT IS A CYCLONE...?
Cyclones are simple tanks
with no moving parts and
have been used for wood dust
separation for over seventy
years.
Cyclones are made up of just
a few parts, an air inlet, an
outer cylinder, an air outlet,
and cone with dust chute
that connects to a collection
bin.
Dirty air comes in through
the inlet.
Heavy particles i.e., the
unburnt coal falls at the
bottom outlet.
This is connected to the coal
inlet to allow the unburnt
particles to undergo
combustion.
29. THERE ARE TWO TYPES OF CYCLONE:
HOT CYCLONE
COLD CYCLONE
In this type the
temp. is greater than
700oc
Here the temperature
remains between
400-500oc.
30. ELECTROSTATIC
PRECIPITATOR...
ESP is used for
reduction of
particulate matter
(PM) in flue gas
generated due to
the combustion of
Indian coal.
This coal is
characterized by
high ash content,
low calorific value
and low sulphur
content resulting
in the generation
of a very large
amount of highly
electrically-
resistive fly-ash
31. HOW
DOES AN
ESP
WORK...?
It has electrodes through which electricity in the range of
10000 kV is passed when flue gas enters into the
precipitator.
Hence the gas gets divided into (+)ve and (-)ve ions which
are then attracted towards the electrodes and stick to it.
In hirakud there is a hammering operation which hammers
the electrode from time to time so that the contents get
collected in the hopper below which are then transferred.
32. A low efficiency (65%), high throughput
cyclone is considered for pre-cleaning flue gas
and the ESP is designed for removal of the
remaining 35% fly-ash from the flue gas.
34. WHAT IS A
TURBINE...?
Turbine is a prime
mover.
It converts potential
energy into kinetic
energy.
Here the temperature
& pressure is around
510oc & 90 kg
respectively.
It is primarily of
three types: impulse,
reaction & compound.
The key parts of a
turbine are a set
of blades (41 blade
assembly in Hirakud
power plant) that
catch the moving
fluid, a shaft
or axle that rotates as
the blades move, and
some sort
of machine that's
driven by the axle.
Each set of blade is
called a stage.
35. THERE ARE TWO TYPES OF
BLADES:
Fixed blade
These blades are
mounted on the
casting.
These are used to
direct the steam
towards the
direction of moving
blades.
Moving blade
These are mounted
on the rotor.
These blades rotate
on their own & are
exactly responsible
for converting
potential energy into
kinetic energy.
36. IMPULSE TURBINE...
In an impulse turbine, a
fast-moving fluid is fired
through a narrow nozzle
at the turbine blades to
make them spin around.
The blades of an impulse
turbine are usually bucket-
shaped.
so they catch the fluid and
direct it off at an angle or
sometimes even back the way
it came (because that gives
the most efficient transfer of
energy from the fluid to the
turbine). In an impulse
turbine, the fluid is forced to
hit the turbine at high speed.
37. REACTION TURBINE...
In a reaction turbine, the
blades sit in a much
larger volume of fluid and
turn around as the fluid
flows past them. A
reaction turbine doesn't
change the direction of
the fluid flow as
drastically as an impulse
turbine
It simply spins as the
fluid pushes through
and past its blades.
Wind turbines are
perhaps the most
familiar examples of
reaction turbines.
38. WORKING OF A
TURBINE...
Steam in superheated
condition from boiler
enters turbine through
valve called control
valve(4 in Hkd)
Opening & closing of
CV is not decided
manually.
Before CV there are
stop valves called
Emergency stop valves
(ESV).
ESV opens only when
all the factors like
temp. & pressure are
satisfied.
ESV is also
hydraulically operated.
There are nozzles on
the surface of the
blades that direct the
flow of the steam.
39. Initial blades are pure
impulse.
Here the 90 kg
pressure is directly
converted into
enthalpy.
Subsequently, the 90 kg &
510oc goes on drooping &
at the end, pressure &
temp. around (0.5-
0.8)kg/cm2 (45-52)oc
respectively is obtained.
This is because of the
compounding factor which
is necessary to increase
enthalpy.
40. The last stage is the exhaust stage.
It leaves the heat out & into the condenser
from where it is transferred to the CEP
(condensate extraction pump).
An ejector type vaccum pump is used to suck
the air out to allow the steam to enter it.
This is cooled by surface type heat exchanger
where pipes containing cold water is entered
into the condenser.
41. Tip loss means the process of loss of steam through
the tip of blades hence the gap between the blades
is kept less (usually in microns).
The steam lost through these parts are subsequently
collected and are taken to HP 1, HP 2, dearator,
LP 1 & LP 2.
The heat from these stages are then used to heat
up the circulating water hence forming a close
circuit.
43. STEAM
GENERATOR...
The steam enters in steam
turbine and due to the
heat energy of steam,
turbine rotates at about
3000 rpm. The turbine
is directly coupled to the
generator rotor.
Electricity is generated as
per the “Faradays Law”
in generator.
FARADAYS FIRST LAW :
Whenever a conductor
cuts magnetic flux,an
emf is induced in that
conductor.
FARADAYS SECOND
LAW : The magnitude of
the induced emf is equal
to the rate of change of
flux linkages.
44. In alternator time varying
magnetic field is produced by
rotating field winding with
help of turbine. Field windings
are wound over rotor of the
alternator and rotor is
coupled to the turbine. Field
windings are connected to the
excitation system through slip
rings. From excitation circuit,
D.C. current is allowed to pass
through the field windings
and produces a magnetic field.
So when the rotor rotates,
D.C. current carrying field
windings also rotates and
produces a time varying
magnetic fieldx
45. This time varying magnetic field is cut by the
stator windings of the alternator and emf is induced
in it of the order of 15.75 KV as per the “Faradays
Law”. Electricity produced in the stator is then
passed though bus ducts to the generator
transformer. GT increases the voltage level from
15.75 KV to 400 KV. This transformer is connected
to 400 KV buses in switchyard through isolators and
a circuit breaker.
51. CONCLUSION...
The HINDALCO- HIRAKUD POWER is
one of the major power plant in ODISHA
as well as in INDIA. We are very grateful
that we got the opportunity to join the
Industrial training project in your
Industry. We are very thankful to all the
respected Employees of the plant who
guided us to get all the knowledge about
the power plant.
