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8/4/2019 Summer Trainig Report Part1
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SUMMER TRAINING REPORT21stJune to 6thAugust
Badarpur Thermal Power Station
Submitted By:-DHRUV
AHUJAB.Tech, 3rd year
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K.I.I.T
This is to certify that DHRUV AHUJA(Roll no. 34039), student
of 2008-2012 Batch ofElectrical & Electronics Branch in 3rd
Year ofKIIT, Bhondsi has successfully completed his industrial
training atBadarpur Thermal Power Station- NTPC, New Delhi
for four weeks from 21st June to 6th August 2011. He has
completed the whole training as per the training report submittedby him.
Training In-charge
Badarpur Thermal Power Station
NTPC
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Badarpur, New Delhi.
Acknowledgement
With profound respect and gratitude, I take the opportunity to convey my thanks to
complete the training here. I express gratitude to the Program Manager and other
faculty members of Electrical & Electronics Engineering Department of KIIT for
providing this opportunity to undergo industrial training at National Thermal
Power Corporation, Badarpur, New Delhi.
I am extremely grateful toMr. G.D.Sharma, Superintendent of Im-Plant Trainingat BTPS-NTPC, Badarpur for his guidance during whole training.
I am extremely grateful to all the technical staff of BTPS-NTPC for their co-
operation and guidance that helped me a lot during the course of training. I have
learnt a lot working under them and I will always be indebted of them for this
value addition in me.
Finally, I am indebted to all whosoever have contributed in this report work and
friendly stay at Badarpur Thermal Power Station, Badarpur, New Delhi.
ABOUT THE COMPANY
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CORPORATE VISION
A world class integrated power major, powering India's growth with increasingglobal presence.
CORE VALUES:
BCOMIT
B- Business ethics
C- Customer focus
O- Organizational & professional pride
M- Mutual respect & trust
I- Innovation & speed
T- Total quality for excellence
NTPC Limited is the largest thermal power generating company of India, Public
Sector Company. It was incorporated in the year 1975 to accelerate power
development in the country as a wholly owned company of the Government of
India. At present, Government of India holds 89.5% of the total equity shares of
the company and the balance 10.5% is held by FIIs, Domestic Banks, Public and
others. Within a span of 31 years, NTPC has emerged as a truly national power
company, with power generating facilities in all the major regions of the country.
NTPC's core business is engineering, construction and operation of power
generating plants and providing consultancy to power utilities in India and abroad.
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The total installed capacity of the company is 31134 MW (including JVs) with 15
coal based and 7 gas based stations, located across the country. In addition under
JVs, 3 stations are coal based & another station uses naphtha/LNG as fuel. By
2017, the power generation portfolio is expected to have a diversified fuel mix
with coal based capacity of around 53000 MW, 10000 MW through gas, 9000 MWthrough Hydro generation, about 2000 MW from nuclear sources and around 1000
MW from Renewable Energy Sources (RES). NTPC has adopted a multi-pronged
growth strategy which includes capacity addition through green field projects,
expansion of existing stations, joint ventures, subsidiaries and takeover of stations.
NTPC has been operating its plants at high efficiency levels. Although the
company has 18.79% of the total national capacity it contributes 28.60% of total
power generation due to its focus on high efficiency. NTPCs share at 31 Mar 2001
of the total installed capacity of the country was 24.51% and it generated 29.68%
of the power of the country in 2008-09. Every fourth home in India is lit by NTPC.
170.88BU of electricity was produced by its stations in the financial year 2005-
2006. The Net Profit after Tax on March 31, 2006 was INR 58,202 million. Net
Profit after Tax for the quarter ended June 30, 2006 was INR 15528 million, which
is 18.65% more than for the same quarter in the previous financial year. 2005).
Pursuant to a special resolution passed by the Shareholders at the Companys
Annual General Meeting on September 23, 2005 and the approval of the Central
Government under section 21 of the Companies Act, 1956, the name of the
Company "National Thermal Power Corporation Limited" has been changed to
"NTPC Limited" with effect from October 28, 2005. The primary reason for this is
the company's foray into hydro and nuclear based power generation along with
backward integration by coal mining.
A graphical overview
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STRATEGIES
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OPERATION
Introduction
Steam Generator or Boiler
Steam Turbine Electric Generator
Introduction
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The operating performance of NTPC has been considerably above the national
average. The availability factor for coal stations has increased from 85.03 % in
1997-98 to 90.09 % in 2006-07, which compares favourably with international
standards. The PLF has increased from 75.2% in 1997-98 to 89.4% during the year
2006-07 which is the highest since the inception of NTPC.
Operation Room of Power Plant
In Badarpur Thermal Power Station, steam is produced and used to spin a turbine
that operates a generator. Water is heated, turns into steam and spins a steam
turbine which drives an electrical generator. After it passes through the turbine, the
steam is condensed in a condenser; this is known as a Rankine cycle. Shown here
is a diagram of a conventional thermal power plant, which uses coal, oil, or natural
gas as fuel to boil water to produce the steam. The electricity generated at the plant
is sent to consumers through high-voltage power lines.
The Badarpur Thermal Power Plant has Steam Turbine-Driven Generators which
has a collective capacity of 705MW.The fuel being used is Coal which is supplied from the Jharia Coal Field in
Jharkhand.
Water supply is given from the Agra Canal.
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Table: Capacity of Badarpur Thermal Power Station, (BTPS) New Delhi
There are basically three main units of a thermal power plant:
1. Steam Generator or Boiler
2. Steam Turbine
3. Electric Generator
We have discussed about the processes of electrical generation further. A complete
detailed description of two (except 2) units is given further.
Coal is conveyed (14) from an external stack and ground to a very fine powder by
large metal spheres in the pulverised fuel mill (16). There it is mixed withpreheated air (24) driven by the forced draught fan (20). The hot air-fuel mixture is
forced at high pressure into the boiler where it rapidly ignites. Water of a high
purity flows vertically up the tube-lined walls of the boiler, where it turns into
steam, and is passed to the boiler drum, where steam is separated from any
remaining water. The steam passes through a manifold in the roof of the drum into
the pendant super heater (19) where its temperature and pressure increase rapidly
to around 200 bar and 540C,
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sufficient to make the tube walls glow a dull red. The steam is piped to the high
pressure turbine (11), the first of a three-stage turbine process. A steam governor
valve (10) allows for both manual control of the turbine and automatic set-point
following. The steam is exhausted from the high pressure turbine, and reduced in
both pressure and temperature, is returned to the boiler reheater (21). The reheated
steam is then passed to the intermediate pressure turbine (9), and from there passed
directly to the low pressure turbine set (6). The exiting steam, now a little above its
boiling point, is brought into thermal contact with cold water (pumped in from the
Cooling tower) in the condenser (8), where it condenses rapidly back into water,
creating near vacuum-like conditions inside the condensor chest. The condensed
water is then passed by a feed pump (7) through a deaerator (12), and pre-warmed,
first in a feed heater (13) powered by steam drawn from the high pressure set, and
then in the economiser (23), before being returned
to the boiler drum. The cooling water from the condensor is sprayed inside a
cooling tower (1), creating a highly visible plume of water vapour, before beingpumped back to the condensor (8) in cooling water cycle. The three turbine sets are
sometimes coupled on the same shaft as the three-phase electrical generator (5)
which generates an intermediate level voltage (typically 20-25 kV). This is stepped
up by the unit transformer (4) to a voltage more suitable for transmission (typically
250-500 kV) and is sent out onto the three-phase transmission system (3). Exhaust
gas from the boiler is drawn by the induced draft fan (26) through an electrostatic
precipitator (25) and is then vented through the chimney stack (27).
Steam Generator/BoilerThe boiler is a rectangular furnace about 50 ft (15 m) on a side and 130 ft (40 m)
tall. Its walls are made of a web of high pressure steel tubes about 2.3 inches (60
mm) in diameter. Pulverized coal is air-blown into the furnace from fuel nozzles at
the four corners and it rapidly burns, forming a large fireball at the center. The
thermal radiation of the fireball heats the water
that circulates through the boiler tubes near the boiler perimeter. The water
circulation rate in the boiler is three to four times the throughput and is typically
driven by pumps. As the water in the boiler circulates it absorbs heat and changesinto steam at 700 F (370 C) and 3,200 psi (22.1MPa). It is separated from the
water inside a drum at the top of the furnace. The saturated steam is introduced
into superheat pendant tubes that hang in the hottest part of the combustion gases
as they exit the furnace. Here the steam is superheated to 1,000 F (540 C) to
prepare it for the turbine. The steam generating boiler has to produce steam at the
high purity, pressure and temperature required for the steam turbine that drives the
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electrical generator. The generator includes the economizer, the steam drum, the
chemical dosing equipment, and the furnace with its steam generating tubes and
the superheater coils. Necessary safety valves are located at suitable points to avoid
excessive boiler pressure. The air and flue gas path equipment include: forced draft
(FD) fan, air preheater (APH), boiler furnace, induced draft (ID) fan, fly ash
collectors (electrostatic precipitator or baghouse) and the flue gas stack.
For units over about 210 MW capacity, redundancy of key components is provided
by installing duplicates of the FD fan, APH, fly ash collectors and ID fan with
isolating dampers. On some units of about 60 MW, two boilers per unit may
instead be provided.
Schematic diagram of a coal-fired power plant steam generator
Boiler Furnace and Steam Drum
Once water inside the boiler or steam generator, the process of adding the latent
heat of vaporization or enthalpy is underway. The boiler transfers energy to thewater by the chemical reaction of burning some type of fuel.
The water enters the boiler through a section in the convection pass called the
economizer. From the economizer it passes to the steam drum. Once the water
enters the steam drum it goes down the down comers to the lower inlet water wall
headers. From the inlet headers the water rises through the water walls and is
eventually turned into steam due to the heat being generated by
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the burners located on the front and rear water walls (typically). As the water is
turned into steam/vapour in the water walls, the steam/vapour once again enters the
steam drum.
External View of an Industrial Boiler at BTPS, New Delhi
The steam/vapour is passed through a series of steam and water separators and then
dryers inside the steam drum. The steam separators and dryers remove the water
droplets from the steam and the cycle through the water walls is repeated. This
process is known as natural circulation. The boiler furnace auxiliary equipment
includes coal feed nozzles and igniter guns, soot blowers, water lancing and
observation ports (in the furnace walls) for observation of the furnace interior.
Furnace explosions due to any accumulation of combustible gases after a tripout
are avoided by flushing out such gases from the combustion zone before igniting
the coal. The steam drum (as well as the superheater coils and headers) have air
vents and drains needed for initial start-up. The steam drum has an internal device
that removes moisture from the wet steam entering the drum from the steam
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generating tubes. The dry steam then flows into the superheater coils. Geothermal
plants need no boiler since they use naturally occurring steam sources. Heat
exchangers may be used where the geothermal steam is very corrosive or contains
excessive suspended solids. Nuclear plants also boil water to raise steam, either
directly passing the working steam through the reactor or else using an
intermediate heat exchanger.
Fuel Preparation System
In coal-fired power stations, the raw feed coal from the coal storage area is first
crushed into small pieces and then conveyed to the coal feed hoppers at the boilers.
The coal is next pulverized into a very fine powder. The pulverisers may be ball
mills, rotating drum grinders, or other types of grinders. Some power stations burn
fuel oil rather than coal. The oil must kept warm (above its pour point) in the fueloil storage tanks to prevent the oil from congealing and becoming unpumpable.
The oil is usually heated to about 100C before being pumped through the furnace
fuel oil spray nozzles.
Boiler Side of the Badarpur Thermal Power Station, New Delhi
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Boilers in some power stations use processed natural gas as their main fuel. Other
power stations may use processed natural gas as auxiliary fuel in the event that
their main fuel supply (coal or oil) is interrupted. In such cases, separate gas
burners are provided on the boiler furnaces.
Fuel Firing System and Igniter System
From the pulverized coal bin, coal is blown by hot air through the furnace coal
burners at an angle which imparts a swirling motion to the powdered coal to
enhance mixing of the coal powder with the incoming preheated combustion air
and thus to enhance the combustion. To provide sufficient combustion temperature
in the furnace before igniting the powdered coal, the furnace temperature is raised
by first burning some light fuel oil or processed natural gas (by using auxiliary
burners and igniters provide for that purpose).
Air Path
External fans are provided to give sufficient air for combustion. The forced draft
fan takes air from the atmosphere and, first warming it in the air preheater for
better combustion, injects it via the air nozzles on the furnace wall. The induced
draft fan assists the FD fan by drawing out combustible gases from the furnace,
maintaining a slightly negative pressure in the furnace to avoid backfiring through
any opening. At the furnace outlet and before the furnace gases are handled by theID fan, fine dust carried by the outlet gases is removed to avoid atmospheric
pollution. This is an environmental limitation prescribed by law, and additionally
minimizes erosion of the ID fan.
Auxiliary Systems
Fly Ash Collection
Fly ash is captured and removed from the flue gas by electrostatic precipitators or
fabric bag filters (or sometimes both) located at the outlet of the furnace and before
the induced draft fan. The fly ash is periodically removed from the collection
hoppers below the precipitators or bag filters. Generally, the fly ash is
pneumatically transported to storage silos for subsequent transport by trucks or
railroad cars.
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Bottom Ash Collection and Disposal
At the bottom of every boiler, a hopper has been provided for collection of the
bottom ash from the bottom of the furnace. This hopper is always filled with water
to quench the ash and clinkers falling down from the furnace. Some arrangement isincluded to crush the clinkers and for conveying the crushed clinkers and bottom
ash to a storage site.
Boiler Make-up Water Treatment Plant and Storage
Since there is continuous withdrawal of steam and continuous return of condensate
to the boiler, losses due to blow-down and leakages have to be made up for so as to
maintain the desired water level in the boiler steam drum. For this, continuous
make-up water is added to the boiler water system. The impurities in the raw water
input to the plant generally consist of calcium and magnesium salts which imparthardness to the water. Hardness in the make-up water to the boiler will form
deposits on the tube water surfaces which will lead to overheating and failure of
the tubes. Thus, the salts have to be removed from the water and that is done by a
Water Demineralising Treatment Plant (DM).
Ash Handling System at Badarpur Thermal Power Station, New Delhi
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A DM plant generally consists of cation, anion and mixed bed exchangers. The
final water from this process consists essentially of hydrogen ions and hydroxide
ions which is the chemical composition of pure water. The DM water, being very
pure, becomes highly corrosive once it absorbs oxygen from the atmosphere
because of its very high affinity for oxygen absorption. The capacity of the DM
plant is dictated by the type and quantity of salts in the raw water input. However,
some storage is essential as the DM plant may be down for maintenance. For this
purpose, a storage tank is installed from which DM water is continuously
withdrawn for boiler make-up. The storage tank for DM water is made from
materials not affected by corrosive water, such as PVC. The piping and valves are
generally of stainless steel. Sometimes, a steam blanketing arrangement or
stainless steel doughnut float is provided on top of the water in the tank to avoid
contact with atmospheric air. DM water make-up is generally added at the steam
space of the surface condenser (i.e., the vacuum side). This arrangement not only
sprays the water but also DM water gets deaerated, with the dissolved gases beingremoved by the ejector of the condenser itself.