1 PROJECT REPORT VOCATIONAL TRAINING AT Kanti Bijlee Utpadan Nigam Limited . (A Joint Venture Of NTPC Ltd. & BSEB) Kanti , Muzaffarpur. FROM 13/04/2013 TO 12/05/2013 Submitted By , SUSHANT KUMAR ELECTRONICS & INST. ENGG. GURU NANAK INSTITUTE OF TECH. WEST BENGAL UNIVERSITY OF TECHNOLOGY BATCH:-2010-2014
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SUMMER Training report AT NTPC FOR INSTRUMENTATION (kbunl)
TRAINING REPORT FOR 1 MONTH SUMMER TRAINING AT NTPC KANTI, MUZAFFARPUR,BIHAR
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PROJECT REPORT
VOCATIONAL TRAINING AT Kanti Bijlee Utpadan Nigam Limited .
(A Joint Venture Of NTPC Ltd. & BSEB) Kanti , Muzaffarpur.
FROM 13/04/2013 TO 12/05/2013
Submitted By ,
SUSHANT KUMAR
ELECTRONICS & INST. ENGG.
GURU NANAK INSTITUTE OF TECH.
WEST BENGAL UNIVERSITY OF TECHNOLOGY
BATCH:-2010-2014
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ACKNOWLEDGMENT
I am highly indebted to HOD of C& I Department, all faculty members of
department for providing me an opportunity to have practical exposure at
KBUNL/MTPS Kanti (Joint venture of NTPC Ltd & BSEB)
I express my sincere thanks to Sh. S Mundle (AGM, C&I) for giving me an
opportunity to take such valuable vacational training in his department.
I also pay my sincere gratitude to Sh.J P Kushwaha (Dy. MGR,C&I) , Sh.
Anjani Kr Verma (Asst. MGR,C&I), Sh. R N Verma (Asst. MGR,C&I),
Vikas Kumravat(Asst. MGR,C&I) & Vikas Koshta(Asst. MGR,C&I) for
their continuous assistance, guidence and valuable suggestions .
Last but not the least I am also thankful to Sh. Arun Kr Singh for his
contribution.
My special thanks to HR deptt for faciliating me to impart training at this
project.
Submitted by:
SUSHANT KUMAR
B.TECH(Electronics & Instru. Engg.)
‘VI’ th Semester
Roll No. - 14300510053
Guru Nanak Institute of Tech.
West Bengal University of tech. (Kolkata)
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ABSTRACT
Any thermal power plant is converting the chemical energy of fossil
fuel (coal) into electrical energy. The process involved for this
conversion is based upon the Modified Rankine Cycle. The major
components that are used to accomplish the modified rankine cycle
are
Boiler feed pump,
The steam generator water walls (evaporator),
Steam generator super heaters,
Steam turbine,
Reheater,
Condenser,
Regenerative feed heaters etc.
All components of a power generating cycle are vital and critical in
operation. In Modified Rankin Cycle, the two most important aspects
that is added are reheating & regenerative heating. By reheating we used
to send the steam coming from exhaust of the turbines back to the
reheater of the boiler so that its enthalpy increases and more work can
be done by this steam the other purpose is to make steam dry so that no
harm will be done to the blades of the turbine.
In MTPS Kanti, we have three turbines in Tandem coupling namely
one H.P Turbine, one I.P Turbine & one L.P Turbine coupled with
the generator to which is synchronized with the grid to produce
electricity at 50Hz.
In all my modesty, I wish to record here that a sincere attempt has
been made for the presentation of this project report. I also trust that
this study will not only prove to be of academic interest but also will
be able to provide an insight into the area of technical management.
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CONTENT
Sl No. Description Page-No 01 An Over View -6-
02 Process of Generation of Electricity -9-
03 Light Up Process -11-
04 Milling System -11-
05 Main Boiler Components -13-
06 Electrostatic Precipitator -17-
07 Air Heaters -17-
08 Types of Fan -18-
09 Types of Pump -19-
10 Types of Cycle -20-
11 Types of Heater -22-
12 Types of Turbine -23-
13 Flame Scanner -24-
14 Important Control Loops in a Thermal
Power Plant -25-
15 Unit Control Desk and Panels -30-
16 References -31-
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AN OVERVIEW
NTPC NTPC was set up in 7th November 1975, the MAHARATNA power giant today generates
more than one fourth of the total power in the country, Ranked 5th largest power
generating utility in the world, NTPC is the second most efficient in capacity utilization
among the top ten thermal generating companies according to a survey conducted by
Data Monitor, United kingdom. In a short span of two decades, NTPC has earned its
prime status by setting up a total generating capacity of 22,249 MW. With 19.14% of
India’s operating capacity, the company generates 26.7% of country electricity through
its 13 coal and 7 gas based power plants spread all over the country.
Today, the country needs a 10 percent sustained growth in power generation to ensure the
momentum for a 7 percent overall growth in the economy. Recognizing this, NTPC has
committed itself to achieving the status of a 30,000MW plus company by the year 2007
and 40,000MW plus company by the year 2012 and power generating capacity addition
programme of 51,000 MW (Including nuclear energy and non-conventional sources of
energy) for the tenth plan.
New technology
Super critical technology at NTPC Sipat project (3X600MW) to increase the
efficiency of the cycle and to decrease the green house gas emission.
Closed cycle seawater cooling at Simhadri project for first time in India.
Introduction of IGCC (Integrated gasified combined cycle) for clean and efficient
utilization of coal.
Environment management
Liquid water treatment plants at Farakka and Kahalgaon.
Ash water recycling system at Kahalgaon and Korba to reduce water requirement for
ash disposal at these station
PLANT INTRODUCTION Salient Features Of Boiler Plant 1. General a) Type of boiler Single drum tangential firing &
reheat type.
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b) Type of fuel used Pulverized coal (Main Fuel)
Heavy oil & L.D.O. (for light up
& flame stabilization)
c) No. of Mills 6
d) Type of Mills Pressurized type Bowl Mill
e) Furnace Balanced draught
f) P.A. Fans 2 nos. (each 60% capacity)
g) F.D. Fans 2 nos. (each 60% capacity)
h) I.D. Fans 3 nos. (one standby)
(each 60% capacity)
i) Air Heater 2 nos.
j) Type of Air Heater Trisector regenerative
k) Electrostatic Precipitator 1 nos.
2. M.C.R. Parameter M.C.R. Value
a) S.H. Outlet Steam Flow 375 T/Hr
b) R.H. Steam Flow 331 T/Hr
c) Pressure at S.H. Outlet 141.5 Ata
d) Temp. at S.H. Outlet 540oC
e) Pressure at R.H. Inlet 37 ata
f) Pressure at R.H. Outlet 32.9 ata
g) Temp. at R.H. Inlet 369oC
h) Temp. at R.H. Outlet 540oC
i) Pressure in Drum 148.69 ata
j) Design Pressure 158.0 kg/cm2
k) Flue Gas temp. leaving
Economiser 350oC
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l) Flue Gas temp. leaving
Air Heater 142oC
m) Feed Water Temp. before
Economizer 235oC
Salient Feature Of Turbine
1. General
a) Type Of Turbine Reheat
b) No. Of Cylinders 3 (HP,IP & LP)
c) No. Of LP Heater 5
d) No. Of HP Heater 2
e) Deaerator 1 (Variable pressure type)
f) No. Of Extraction pump 3 (one standby)
g) No. Of BFP 2 (one standby)
2. M.C.R. Parameter M.C.R. Value
a) Rated output 110 MW
b) M.S. Pressure at H.P. turbine inlet 130 ata
c) M.S. temp. at H.P. turbine inlet 535oC
d) H.R.H. temp. at I.P. turbine inlet 535oC
e) Turbine speed 3000 rpm
f) Condenser Vacuum 0.1 kg/cm2 (abs)
g) No. of Extraction 7
h) Quantity of cooling water 15,400 m3/hr
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Salient Feature Of Generator
a) Rating Continuous
b) Active Output 110 MW
c) Rated Voltage 11000 +/- 5% V
d) Rated Current 7220 A
e) Power Factor 0.8 Lagging
f) Frequency 50 Hz
g) Excitation System Static type
h) Field Current at rated output 1335 A
i) Type of Cooling System Hydrogen Cooled
j) Hydrogen Pressure 2 ata
k) No. of H2 Cooled elements 6
l) Cooling Medium for H2 Soft water
PROCESS OF GENERATION OF ELECTRICITY
MTPS Kanti is a Thermal Power Plant. The functioning of every thermal power plant is based
on the following processes: -
1. Coal To Steam.
2. Steam To Mechanical Power
3. Power Generation, Transmission & Distribution.
Coal To Steam
Coal and Water are primary inputs to a thermal power plant.
This process of conversion of water to steam by using the heat energy
Produced by burning coal for producing heat takes place in the boiler
and its auxiliaries. Coal burns in a furnace located at the bottom
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part of the boiler. Feed water is supplied to the boiler drum by boiler
feed pumps, where water is heated and converted into saturated steam
This is further superheated in the super heaters.
water
Coal
SM
To Condensers
GENERATOR TRANSFORMER(400KV)
Steam to Mechanical Power.
This is the most important process of a power plant. The superheated
Steam produced in the boiler at high pressure and temperature is feed
to the turbine. The steam expands in the turbine giving up heat energy, which is
transformed into mechanical energy on turbine shaft. Thus,
Mechanical power is obtained from the turbine shaft.
BOILER
GENERATOR
TURBINE
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Turbine
Power Generation, transmission &
Distribution
Mechanical power produced at the shaft of the turbine is used to
rotate the rotor of an electrical generator that produces electric
power. The electric power produced by the generator is boosted to a
higher voltage by a generator transformer to reduce the transmission
losses.
This power at EHV i.e. 400 kV is transmitted and distributed by EHV transmission
lines.
GENERATOR A generator consists of rotor which consists of carbon brushes. The rotor rotates at 3000rpm
in case of any fault if production of plants stops then we have bearing motor which rotates
shaft of turbine continuously and rotor at 65rpm. This is because if shaft doesn’t rotates then
due to load it may bend.
As generator produces 110MW or generates 11kv output. The output of generator is step up
to 220kv by using step up transformer or generating transformer. Three phase is fed to station
transformer. There are two station transformer1 and 2 which is step down transformer. Here
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220kv is step down to 6.6kv for internal purpose. This 6.6kv is step down to 415v for low
rating motors. At generating transformer we are using lighting arrestor which protects G.T
from lighting. This 220kv is given to grid substation. In grid substation we are using some
protective system before distribution we have Bus isolator, SF6 breaker, Line isolator, CT,
lightning arrestor. Similarly we have two unit auxiliary transformer UAT-1 and UAT-2,
which will step down voltage from 11kv to 6.6kv and it will supply to unit auxiliary board
1BA, 1BB.
Similarly station transformer will supply to station board 9BA, 9BB. One unit is tie with
other unit because during the failure of any one of the unit other unit will able to supply.
LIGHT UP PROCESS MTPS Kanti has direct firing system. In this system, a controlled quantity of crushed
coal is fed to each bowl mill (pulveriser) by its respective feeders and primary air is
supplied from the primary air fans which dries the coal as it is being pulverized and
transports the pulverized coal through the coal piping system to the coal burners.
There are six pulverisers out of which four are used and two remains in standby. The
raw coal feeders supply 74 TPH of coal to each mill.
The pulverized coal and air discharged from the coal burners is directed towards the
center of the furnace to form firing ball.There are 24 tilting, tangentially fired coal
burners fitted at the four corners of the boiler at six elevations.
The secondary air heating system supplies secondary air for combustion in the furnace
around the pulverized coal burners and through auxiliary air compartments directly
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adjacent to the coal burner compartments. There are 12 air-atomizing ignitors per
boiler, which initially ignite the coal and air mixture.
Above a predictable minimum loading condition, the ignition becomes self-sustaining.
Combustion is completed as the gases spiral up in the furnace.
MILLING SYSTEM
1. COAL BUNKER: - These are in-process storage silos used for storing crushed coal coming from the coal
handling plant through conveyor belts.
There are six coalbunkers supplying coal to each mill and are located at top of the mills to aid
in gravity feeding of the coal. Each bunker can store coal, which can be used for 12hrs.
2. COAL FEEDER: -
The purpose of coal feeder is to transfer coal at a pre- determined rate, from coalbunker to
the mill.
The coal feeder comprises two continuous chains with L sections flight bars mounted
between the chains at every fifth link .The chains runs on sprockets mounted at each end of
the feeder to given an upper strand movement towards the driven ends and a lower strand
movement in the opposite direction. The drive shaft is supported on two self aligning bearing
mounted in the Plummer block on support out side the feeder casing, shaft sealing is
achieved by the lip seals in the sealing housing and mounted in board of the bearing to abut
the feeder casing.
The tail sprocket shaft is mounted in adjustable bearing blocks adjacent to the feeder casing
with positioned which allow the feeder chain to be tensioned.
Both upper and lower strands run over full width carrying plates with the lower strands
located by angle section guides mounted on the feeder wall. The upper and lower carrying
plates and the inside wall are protected from wear by replaceable stainless steel panels,
chains are kept clean by rubber wiper.
Feeder input is achieved by roller chain drive to the conveyor via a fixed speed electric motor
driving a variable speed gear box, torque limiter and fixed out put gear box The electric
motor is flanged mounted to variable speed gear box, coupled to the fixed output gear box by
a flexible coupling and torque limiter.
The principle of operation of coal feeder is that coal flows from the bunker into the chain
feeder via feed hopper and is conveyed to the mill, when the feeder is in the operation, the
conveyor chain drag a fixed head of coal towards the driven ends of the feeder. At the end of
the carrying plates the coal falls through the conveyor onto the bottom plate, where it is
picked up by the returning flight bars and dragged back along the feeder to fall into the mill.
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3. PULVERISER MILL :-
There are six mills located adjacent to the furnace at 0 m level .These mills pulverize coal to
desired fineness to be fed to the furnace for combustion .
The main structure of the pulverisering mill is fabricated from mild steel in three cylindrical
sections, the bottom section (the mill housing support )which support the entire unit and
encloses the mill drive gear unit, a center section (the mill housing)that contains the rotary
grinding element and upper section (the classifier housing )comprising an accommodate the
gas loading cylinders of the mill loading gear .A platform around the upper section provide
an access to an inspection door and to the top of the mill routine maintenance and is served
by detachable ladder .
The grinding element comprises of 3 rotatory rollers.
The raw coal enter the mill through inlet and fall into the grinding zones ,where rotating
bottom grinding and transport coal through the grinding element into the primary air stream
.The primary air enters through the inlet duct in the mill while goes to the furnace from four
outlet ducts at the top of the mill.
The ground fuel particle are picked up by the primary air stream after it is passed through the
throat plates and carried upwards towards the classifier .The larger particle are initially
carried upwards by the air stream and circulate over the upper grinding ring before falling
back into the grinding zone by virtue of their weight .The coal /air mixture then passes into
the classifier ,where any remaining oversize particle are separated out and fall down to the
return skirt until their commutative weight is sufficient to deflect the flaps and return them
into the grinding zone .
The setting of the classifier vane control the fineness of the ground product .
Heavy material such as pyrites and tramp iron which has passed through grinding zone
without being pulverized is carried around throat plate and discharged through a counter
balance relief gate into the space below the yoke .
. Main Boiler Components
The major accessories of a steam-generating unit are listed as below:
Furnace.
Economizer.
Boiler drum.
Downcomers.
Water walls.
Riser tubes.
Superheaters.
Reheaters.
Desuperheaters.
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1. Furnace
A boiler furnace is the first pass of the boiler in which fuel is burned and from which the
combustion products pass to the super heater and second pass of boiler.
The combustion process is a continuous process, which takes place in first pass of the boiler
and controlled by fuel input through coal feeders. It is a radiant type and water-cooled
furnace and enclosure is made up of water wall.
The furnace is open at the bottom to allow ash/clinkers to fall freely into the furnace bottom
ash hopper (through a ‘furnace throat’), and at the top of its rear wall, above the arch, to
allow hot gases to enter the rear gas pass.
The basic requirements that a furnace must satisfy are:
1. Proper installation, operation and maintenance of fuel burning equipment.
2. Sufficient volume for combustion requirements.
3. Adequate refractories and insulation.
2. Economiser The function of an economizer in a steam-generating unit is to absorb heat from the flue
gases and add this as sensible heat to the feed water before the feed water enters the
evaporative circuit of the boiler. This additional heating surface in the path of the feed water
increases the efficiency of the steam generating cycle, saving in fuel consumption, thus this
additional surface was named as ‘economizer’.
The economizer is placed in the path of the flue gases leaving the boiler, in the boiler rear
gas pass below the rear super heater.
The economizer is continuous ‘unfinned loop type’ and water flows in upward direction and
gas flows in the downward direction. Since water flow is from bottom to top so if any steam
is formed during the heat transfer it also moves along with water and prevent the lock up
steam which will cause overheating and failure of economizer tube.
A recalculation line with a stop valve and non return valve is incorporated to keep
circulation in economizer into boiler drum when there is fire in furnace but it prevents the
feed water flow into the boiler drum.
3. Boiler drum
The boiler drum is a cylindrical pressure vessel with hemispherical ends. It contains two
rows of cyclone separators, four rows of drier boxes, a perforated feed water distribution
pipe, and a chemical dosing pipe.
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The boiler drum is located on the upper front of the boiler. It is suspended from roof
steelwork by two u-shaped slings.
It forms a part of the water circulation system of the boiler. The drum serves mainly two
functions:
The first and primary one is that it separates steam from the mixture of water and
steam discharged into it and to reduce the dissolved solid contents of the steam to
below the prescribed limit of 1 ppm.
Secondly, the drum houses all equipments used for purification of steam after being
separated from water. These equipments are known as ‘drum internals’.
Drum internals These are the equipments, which are used to separate water from steam and to direct the flow
of water and steam to obtain an optimum distribution of drum metal temperature in boiler
operation. The drum internals consists of baffle arrangements, devices which change the
direction of flow of steam and water mixture, separators employing spinning action for
removing water from steam or steam purifiers as washers and screen dryers.
Steam output. So, the drum size is determined by the space required to accommodate the
steam separating and purifying equipments. The level of water in the stream is monitored by
control and interlock equipment.
Drum level is monitored by four level transmitters which are connected across individual
drum mounted, short-range constant head chambers.
Water level gauge is mounted on each end of the steam drum. If water level goes outside of
the prescribed operating limit then the boiler is tripped.
Transformer:- A transformer is an electrical device which works on the principle of
mutual induction. The autotransformer used in power station. It has three windings primary,
secondary and tertiary. The 220kv voltage is fed as input to primary by step down 132kv fed
MTPS as input
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4. Downcomers Down comers provide a passage for water from the boiler drum to bottom ring header. From
bottom ring header the water goes to water walls for heat absorption and conversion into
steam heating .To achieve the circulation of water into water wall Boiler circulation pumps
are provided in down comers.
5. Waterwalls Water walls are the necessary elements of the boiler. They serve as the means of heating and
evaporating the feed water supplied to the boiler from the economizers via boiler drum and
down comers.
In large boilers, water walls completely cover the interior surfaces of the furnace providing
practically complete elimination of exposed refractory surface. They usually consist of
vertical tubes membrane and are connected at the top and at the bottom to headers. These
tubes receive water from the boiler drum by means of down comers connected between drum
and water walls lower header.
Water walls absorb 50 percent of the heat released by the combustion of fuel in the furnace,
which is utilized for evaporation of feed water. The mixture of water and steam is discharged
from the top of the water walls into the upper wall header and then passes through riser tubes
to the steam drum.
The design and construction of the water walls depends upon the combustion and steam
conditions and the size of the boiler.
6. Riser tubes
A riser is a tube through which the mixture of water and steam pass from an upper water wall
header to the steam drum.
7. Superheater
The steam generated by the boiler is usually wet or at the most dry saturated because it is in
direct contact with water. So, in order to get superheated steam, a device known as
superheater has to be incorporated in the boiler.
The function of the superheater system, is to accept dry saturated steam from the steam drum
and to supply superheated steam at the specified final temperature of 540oC, by means of a
series of heat transfer surfaces arranged within the boiler gas passes.
A superheater is a surface type heat exchanger generally located in the passage of hot flue
gases. The dry saturated steam from the boiler drum flows inside the superheater tubes and
the hot flue gases flows over the tubes and in this way its temperature is increased at the
same pressure.
The super heater consists of three sections classified as primary super heater, secondary super
heater and final super heater. In Kanti, there are 14 super heater coils which are divided into
above different sections where temperature is increased from approx. 340oC to 540oC.
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Dry saturated steam from the drum passes through the three sections of super heater,
increasing the temperature to approx. 540oC as it travels through each section.
8. Reheater A reheater is a device that is incorporated in the upper arch of the boiler near the gooseneck
in the path of the outgoing flue gases. As the name indicates, it reheats the
outlet steam from the HP turbine and thus increasing its temperature up to the desired value.
The reheater accept cold reheat steam from the HP turbine exhaust and supply hot reheat
steam at the specified outlet steam temperature of 540oC by means of heat transfer surfaces
arranged within the boiler gas passes.
The reheater consists of 2 heating coils which finally raise the temperature of the steam to the
required level.
Steam from the HP turbine exhaust enters the reheater system through two parallel mounted
spray water desuperheaters liners located in the cold reheat pipe work, then passes through
reheater, increasing the temperature as it travels through it. Reheater
outlet temperature is controlled by raising or lowering the angle of burner tilt.
When this reheated steam enters the IP turbine, the net efficiency of the cycle is increased.