Kolaghat Thermal Power Station
&
Bakreswar Thermal Power Station
Report Submitted By:
NAME
ROLL NO
SARTHAKCHATTERJEE
GHOSH
KRISHNENDU
11501619019
11501619042
Content
1.Introduction of WBPDCL
2.Introduction of KTPP
3.Introduction of BKTPP
4.Introduction of thermal
power plant
5.Working diagram of
thermal power plant
6.Working of thermal
power plant
7.Three Major Inputs to
Power Station
8.Fire and Safety
9.Types of Fire Extinguisher
10.Coal Handling Plant
11.Pulverizing Plant
12.Boiler
13.Steam Turbine
14.Generator
15.Condenser
16.Hot-Well
17.Cooling Towers & Ponds
18.Feed Water Heater
19.Economizer
20.Air Pre-heater
21.Switch Yard
22.Ash Handling Plant
23.Boiler Feed Water
Treatment
24.Conclusion
West Bengal Power Development Corporation
Limited (WBPDCL)
West Bengal Power Development Corporation Limited
(WBPDCL) is a company owned by the Government of West
Bengal with the goal to carry on interlay the business of electric
power generation and supply in the state of West Bengal, India.
The main thermal power plants under WBPDCL are in Kolaghat,
Bakreswar, Sagardighi, Santaldih,and Bandel.
The registered & Corporate Office of The West Bengal Power
Development Corporation Limited has been functioning from its
newly constructed own office building at Plot 3/C, Bidyut
Unnayan Bhaban, LA Block, Sector III, Bidhannagar, Kolkata, West
Bengal 700098 on and from 27th October 2008 (Monday) after
shifting the office from New Secretariate Buildings.
WBPDCL Formed in July 1985 with only one generating unit at
Kolaghat having turnover of Rs.64 Crore paced up further to
Rs.2728 Crores in 2007-08 with 20 units at Kolaghat, Bandel,
Bakreswar,Santaldih
and
Sagardighi.
Kolaghat Thermal Power Station involves a total installed capacity
of 1260 MW. There are Bakreshwar Thermal Power Station plants
having a capacity of 1050MW & Sagardighi Thermal Power
Project having capacity of 600MW Bandel Thermal Power Station
and Santaldih Thermal Power Station have been undertaken by
WBPDCL as per re-organization measures of power sector in West
Bengal.
Kolaghat Thermal Power plant (KTPS):
Kolaghat is a census town situated on the banks of
the Rupnarayan River in the Midnapore East district of
West Bengal. It is located in the Panskura II CD Block of
the Tamluk subdivision. It is also the headquarters of
the outback panskura (Panskura II block). Kolaghat
Thermal Power Station is located here, which is one of
the largest power sector in the state and managed by
West Bengal Power Development Corporation Limited
(WBPDCL), a department of the State Government of
West Bengal.
Kolaghat Thermal Power Station has six units of 210
MW each for a total capacity of 1260 MW The units
were commissioned in two stages during the period of
1984 to 1995.
Bakreswar Thermal Power Plant
(BkTPP)
Bakreswar Thermal Power Project, under The
West Bengal Power Development Corporation
Limited, is one of the most reliable and prestigious coal-fired power plants in West Bengal
and in India as well. In two stages the total
capacity of the plant is (05 X 210)MW. Funded
by the Overseas Economic Co-Operation
Fund(OECF) of Japan Govt. — subsequently
constituted as Japan Bank for International Cooperation (JBIC) — this project is one of the first
Fast Track projects to be successfully completed
within scheduled time.
Bakreshwar Dam and Reservoir Project:Constructed across river Bakreshwar, it is an
integral part of Bakreshwar Thermal Power
Project, which relies on the reservoir for
fulfilling its raw water requirements during the
months of April, May and June.
Thermal Power Plant:
A thermal power station is a type
of power station in which heat energy is
converted to electrical energy. In a
steam-generating cycle heat is used to
boil water in a large pressure vessel to
produce high-pressure steam, which
drives a steam turbine connected to
an electrical generator. The lowpressure exhaust from the turbine enters
a steam condenser where it is cooled to
produce hot condensate which is
recycled to the heating process to
generate more high pressure steam. This
is known as a Rankine cycle.
Working diagram of thermal power plant:
THREE MAJOR INPUTS TO POWER STATION:
• Water: Water has been taken from nearby river or dam.
This water is lifted by raw water pumps and is sent to
clarifier to remove turbidity of water. The clear water is
sent to water treatment plant, cooling water system and
service water system. The water is de-mineralized (DM)
by water treatment plant. The DM water is stored in
condensate storage tanks from where it is used in boiler.
• Fuel Oil: The fuel oil used is of two types:(a) Low Sulphur
high stock oil (LSHS) (b) High speed diesel oil (HSD)The
high-speed diesel oil reaches the power station through
the lorry tankers. The oil is stored in large tanks for the
future use in the boiler. Heavy oil is stored in storage
tanks in oil storage yard and is conveyed to the front
through a set of pumps and strainers. The whole length of
piping from the boiler front in stream traced to maintain
the temperature and hence its fluidity so that it can freely
flow in the pipelines.
• Coal: The coal reaches the plant in the railway's wagons.
The unloading of coal is done mechanically by tilting the
wagons by tippler. The coal is sent to the coal storage
yard through the conveyor belts. The crushed coal from
store is sent to the mill bunkers through conveyor belts.
The air which takes away the coal dust passes upward
into the classifier where the direction of flow is changed
abruptly This causes the coarse particle in the air coal
stream to finer coal dust along with the primary air leaves
the classifier onto the coal transport piping from where it
goes to nozzle. Pulverized coal obtained from coal mill
can not be burnt directly.
Working of TPP:
Coal is delivered to the plant via road, rail or ship, and deposited in
a coal yard. Stacker reclaimers are used to gather coal and deposit it
into hoppers, the hoppers then feed flatbed conveyors. Conveyors
transport the coal from the coal yard to day silos within the main power
station building. Each day silo contains enough coal for a set period of
time when the power station is fully loaded e.g. one day silo may contain
enough coal for one boiler at 12 hours of full load operation. The day
silos ensure that any disruption to the supply chain from the coal yard to
the day silos will not cause a disruption to the boiler and consequently
power generation.
Larger power stations may have several large watertube boilers, steam
turbines and generators. It is standard practice for each power
generation building to be referred to as a ‘Block’ e.g. Block A, Block B
etc. Firetube boilers are used to provide the initial heating of the power
plant steam systems.
Day silos feed the boiler directly (old design and uncommon), or, by
passing the coal through a coal pulverizer (standard design and
common). Coal pulverizer increase the coal’s contact surface area with
the air by grinding the coal into small pieces. The pulverizer
also dries the coal in order that combustion can more easily occur
(reduced moisture content). The heat to dry the coal is recovered from
the boiler exhaust gas stream.
Pulverized coal from the pulverizer is blown into the boiler with
the primary air stream. The coal at this stage is finely ground and very
dry, both of these characteristics aid combustion. Combustion occurs
and heat is generated (this plant is a ‘thermal power plant').
The heat generated by the water tube boiler is used to change the state
of water to steam. The steam is then discharged to a condenser steam
turbine.
The steam turbine is connected via a gearbox to an a.c. electrical
generator. Alternating current then passes through switchgear prior to
being distributed to an electrical transformer; the switchgear used will
often be of the SF6 or vacuum design. The electrical transformer
increases the output voltage and is referred to as a ‘generator step-up
(GSU)’ transformer.
The GSU increases the output voltage to match that of the electrical grid,
this may be several hundred thousand volts e.g. 110kV, 220kV etc.
Increasing the voltage reduces transmission losses and reduces the
thickness of the transmission cables required (higher voltage means
lower amps, lower amps means thinner conductors/cables can be
used).
FIRE AND SAFETY
• USE OF PERSONA PROTECTIVE EQUIPMENT'S:
• Appropriate PPE's need to be used based for the job.
• The minimum PPE's to be used for entry or working in
the plant premises are Helmets, Safety Shoes & High
VizJacket.
• For working at height more than 1.8 meters full body
harness must be worn and authorized through Work
Permit.
• For welding, welding shield and leather hand gloves
need to be used.
• Use earplugs while working in high noise areas.
• During mixer cleaning use of face shield is required
and authorized through work permit.
• Wear close fitting uniforms made of cotton materials.
➢THINGS TO REMEMBER WHILE USING PPE'S:
• Always take good care of your PPE's and report any
defects to supervisor.
• While working near rotating machinery do not use of
hand gloves and loose clothing.
• The safety harness must be inspected for any damages
(wear out of ropes, condition of joints) prior to use
implant.
• Never watch a welder at work with unprotected eyes.
• Always wear ear plugs before you enter an area where
there is loud noise.
• Damaged personnel protection (PPE) equipment
should not be used.
DURING EMERGENCY PRIORITY IS TOWARDS SAVING
HUMAN LIFE:
• Do's
• Evacuate immediately from the workplace.
• Proceed towards to emergency assembly point or safe
assembly point.
• Report to emergency rescue team member at Emergency
assembly area.
• Inform missing person information to the rescue team if
you are aware.
• Assist to carry seriously injured personnel to hospital.
• Wait for instructions from emergency coordinator.
• Go back to the work area only after receiving clearance
from emergency coordinator.
• DON'TS
• Do not panic and run.
• Do not attend the emergency if you are not trained.
TYPES OF FIRE EXTINGUISHERS:
Coal handling plant:
Some picture of ktps and bktps chp:
Pulverizing Plant
The main function of the Pulverizers in thermal
power plant is to crush or grind the raw coal
coming from coal handling plant through coal
feeder into a pre-determined size in order to
increase the surface area of the coal.
If the coal is not pulverized , the coal might not
burn completely, thus resulting in wastage of fuel.
Also, pulverization of coal helps the boiler to
respond to load variations more promptly.
Type of coal Pulverizers
1.Slow speed mills like ball mill
2.Medium speed mills like bowl mill
3.High speed impact mill
The slow speed and medium speed mills are
selected for coals ranging from sub-bituminous to
anthracite. The high-speed mills are used for
lignite.
Types of Coal Pulveriser
1.Bowl Mill
2.Ball Mill
3.Impact Mill
Operation of Bowl mill:
In Bowl Mill pulveriser raw coal coming from feeder gets
around between three grinding rolls and bull ring segments
installed on the revolving bowl.
Bowl is made to rotate at medium speed for proper
pulverization of coal. Spring exert necessary pressure on
rolls for grinding. Hot air through the mill besides removing
coal moisture pressure on rolls for grinding . Hot air
through the mill besides removing coal moisture , picks up
the lighter particle and takes them through the classifier
and drop down the higher size particles for further
grinding.
Fine coal mixture leaves the mill and enters the piping
system. Tramp iron pieces which are not required to grind
leaves the bowl due to centrifugal force and removed
through the mill reject handling system.
Operation of ball mill:
The Ball mill pulveriser is basically horizontal
cylindrical tube rotating at low speed on its axis ,
whose length is slightly more to its diameter .
The inside of the cylinder shell is fitted with
heavy cast liners and is filled with cast or forged
balls for grinding , to approximately 1/3 of the
diameter.
Raw coal to be ground is fed from the end and
the product is discharged through the discharge
end. As the shell rotates the balls are lifted up on
the rising side of the shell and they cascade
down from near the top of the shell.
Larger pieces of coal are broken by impact and
the fine grinding is done by attrition and crushing
as the balls roll and slide within the charge. Hot
air flow is induced through the mill in order to
dry the coal and remove the fines from the
pulverizing zone.
If the rate of feed is increased , coarser product
will be obtained and if the speed of rotation is
increased the fineness for the given capacity
increases. During grinding , balls themselves
wear and are continuously replaced by new ones.
Some picture of BKTPS Pulverizer:
A boiler is a pressure vessel which is used to generate high-pressure steam at a saturated
temperature. At this high pressure and temperature generally, bi-drum water tube boilers are
used. Thermodyne Engineering Systems manufactures water tube boilers of various sizes and
capacities that can run on various fuels. Water-tube boiler consists of a furnace enclosed by
the water tubes membrane. The crushed fuel from the crushers is fed into the boiler furnace
over the grate. The hot air from the Forced Draft (FD) fan is mixed with the crushed fuel
causing combustion of fuel. Combustion of fuel generates a lot of radiation heat which is
transferred to water in the membrane tubes. Flue gases generated during combustion travel at
high velocity across the convection bank of tubes thereby heating water through convection
heat transfer. Hot water is sent to a boiler drum at high pressure through the feed-water
pump. The boiler tubes which are in contact with low temperature acts as downcomers to
circulate the water while the tubes which are in contact with high temperature acts as risers
to carryBoiler
steam. This leads to an effective circulation of water thereby preventing the tubes
from getting overheated. The steam leaving the boiler is at saturated temperature and
pressure but there are a lot of heat losses during its transportation to the turbines. So to
increase the quality of steam, steam Superheater is installed in a radiate section of a boiler to
increase its temperature and dryness fraction without increasing its pressure as well as to
accommodate for the transportation temperature losses. The exhaust gases leaving the boiler
are generally at high temperature and this waste heat is extracted by installing
an Economizer or Water Preheaters to preheat the feed water to the boiler and Air
Preheaters to pre-heat the air coming from the Forced Draft Fan required for the combustion
of fuel. Installing this equipment help to decrease the flue gas temperature thereby increasing
the efficiency. The flue gases leaving the boiler also contain some ash particles, so to reduce
the air pollution, flue gases are allowed to pass through the Dust Collectors and Bag Filters to
remove the ash particulates from the flue gases and are sometimes passed through the Wet
Scrubbers to decrease the sulfur content from the gases. The flue gases are drawn through
this equipment using an Induced Draft (ID) Fan which is designed for a fixed capacity and head
to prevent any backpressure. After the ID fan, flue gases are exhausted off into the
atmosphere using a chimney
Types of Boilers:
• Based on tube content:
• Fire Tube
• Water Tube
• Based on operating pressure:
• Ultra-supercritical
boiler:
Pressure ≥ 27.0MPa or rated
outlet temperature ≥ 590 ℃
boiler
• Supercritical boiler: 22.1MPa ≤
Pressure ≤ 27.0MPa
• Subcritical boiler: 16.7MPa ≤
Pressure ≤ 22.1MPa
• Ultra-high pressure boiler:
13.7MPa ≤ Pressure ≤16.7MPa
• High pressure boiler: 9.8MPa ≤
Pressure ≤ 13.7MPa
• Sub-high
pressure
boiler:
5.4MPa ≤ Pressure ≤ 9.8MPa
• Medium
pressure
boiler:
3.8MPa ≤ Pressure≤ 5.4MPa
• Based on fuel used:
• Solid Fuel Fired
• Stoker Fired Boilers
• Pulverized Fuel Boilers
• Fluidized Bed Combustion
(FBC) Boilers
• Oil Fired
• Gas Fired Boilers
• Based on draught system:
• Natural Draught
• Mechanical Draught
• Forced Draught System
• Induced Draught System
• Balanced Draught System
Steam Turbine:
A steam turbine is a machine that extracts thermal
energy from pressurized steam and uses it to do
mechanical work on a rotating output shaft.
Function of steam turbine:• The thermal power plant is equipped with boilers –
some up to 90 meters long – heated by a burner
ignited in a powder with coal, fuel oil vaporized into
fine droplets or natural gas.
• The heat produces used to raise the temperature of
a circuit of water until it turns into steam, which is
then run through a series of turbines under high
pressure.
• The construction of steam turbines is very simple.
This is not a piston rod; flywheel or slide valves are
attached to the turbine. It is a rotor and a set of
rotating blades that attach to the shaft, and the
shaft is placed in the middle of the rotor.
• Turbines exploit a system of blades to spin and,
through a shaft, drive the generator. The generator
is composed of a moving part, rotor, and a
stationary part, the stators.
• The outers layer of the rotor is coated in
electromagnets, and the inner wall of the stators is
lined with coils of copper wires.
• When the rotor turns, it creates a rotating
magnetic field, which induces alternating currents
in the stator.
• The power generated is channeled through a
transformer, which raises the voltage to an
appropriate level for use in power transmission
systems.
Steam Turbine working diagram:
Turbo generator
The generator, typically about 30 feet (9 m) long and 12
feet (3.7 m) in diameter, contains a stationary stator and a
spinning rotor, each containing miles of
heavy copper conductor. There is generally no
permanent magnet, thus preventing black starts. In
operation it generates up to 21,000 amperes at
24,000 volts AC (504 MWe) as it spins at either 3,000 or
3,600 rpm, synchronized to the power grid. The rotor spins
in a sealed chamber cooled with hydrogen gas, selected
because it has the highest known heat transfer
coefficient of any gas and for its low viscosity, which
reduces windage losses. This system requires special
handling during startup, with air in the chamber first
displaced by carbon dioxide before filling with hydrogen.
This ensures that a highly explosive hydrogen–
oxygen environment is not created. The power grid
frequency is 60 Hz across North America and 50 Hz
in Europe, Oceania, Asia (Korea and parts of Japan are
notable exceptions), and parts of Africa. The desired
frequency affects the design of large turbines, since they
are highly optimized for one particular speed. The
electricity
flows
to
a
distribution
yard
where transformers increase the voltage for transmission
to its destination. The steam turbine-driven
generators have auxiliary systems enabling them to work
satisfactorily and safely. The steam turbine generator,
being rotating equipment, generally has a heavy, largediameter shaft. The shaft therefore requires not only
supports but also has to be kept in position while running.
To minimize the frictional resistance to the rotation, the
shaft has a number of bearings. The bearing shells, in
which the shaft rotates, are lined with a low-friction
material like Babbitt metal. Oil lubrication is provided to
further reduce the friction between shaft and bearing
surface and to limit the heat generated.
Turbo Generator Types:
Turbo generators are available in three types which include the
following.
❖Air-cooled Turbo Generator
❖Hydrogen-cooled Turbo Generator
❖Water-cooled Turbo Generator
❑Air-cooled Turbo Generator
Air-cooled turbogenerators are used to provide a modern and high-quality solution for the operation of loads
in different power plants with effortless and inexpensive maintenance. Air-cooled turbo generators are
reliable, robust, and easily maintained. These turbo generators are very flexible to use with other turbines like
steam and gas type within multi or single shaft configurations. These turbogenerators are very helpful in
geothermal applications because due to some severe environmental conditions like humidity and hydrogen
sulfide in the atmosphere. These turbogenerators include cooled stator windings indirectly & cooled rotor
windings directly. These generators are ventilated independently within a closed circuit through air-to-water
coolers. The pressurization kit allows further power extensions. The reduced impact of auxiliary systems
simplifies unit management and cuts the cost of spare parts.
❑Hydrogen-cooled Turbo Generator
A hydrogen-cooled turbo generator uses gaseous hydrogen like a coolant. These types of turbo generators
are mainly designed to provide a low-drag environment, cooling for single-shaft & combined-cycle applications
in combination through steam turbines. So, this generator is most frequently used in different fields due to its
high thermal & hydrogen gas properties. The features of a Hydrogen cooled turbogenerator are long life and
high performance. The hydrogen in this generator increases its performance, efficiency and provides low
frictional losses. There are different models of turbo generators available in the market like optimum
reliability, good quality, and high efficiency. These generators are strong, consistent, and easily maintainable.
This turbo-generator is sealed hermetically to avoid hydrogen gas leakage. The deficiency of oxygen (O2)
within the environment significantly decreases the damage of the insulation of windings. The hydrogen (H2)
gas is dispersed in the rotor field & gets cooled through a heat exchanger of gas to water.
❑Water-cooled Turbo Generator
Water-cooled Turbogenerators are the best solution for the maximum output ranges. These are used in large
power plants due to their solid design. Water-cooled turbogenerators obey PED & ATEX regulations to provide
safe operation when H2 gas is available. All generators including water-cooled stator windings are fixed
through laminated press plates for decreasing different losses and also for eliminating hotspots.
Some picture of BKTPS AND KTPS
Condenser:
The condenser condenses
the steam from the exhaust
of the turbine into liquid to
allow it to be pumped . If
the condenser can be made
cooled , the pressure of the
exhaust steam is reduced
and efficiency of the cycle
increases.
The function of the
condenser are:1. To
provide
lowest
economic heat rejection
temperature for steam.
2.To convert the exhaust
steam to water for
reserve thus saving on
feed water requirement.
3.To introduce make up
water.
Hot well
It acts as a reservoir, and the drain in its bottom allows the
condensate to flow from the condenser, then follow a path to
the boiler, where it will be recycled and put to renewed use
within the power plant.
The water droplets fall like rain from the tube surfaces into
the hot well situated at the bottom of the condenser. This
hot well is essentially a large basin that serves as a collection
point for the condensed water, otherwise known
as condensate.
It’s important to collect the condensate in the hot well and
not just empty it back into the lake, because condensate is
water that has already undergone the process of
purification. It’s been made to pass through a water
treatment plant prior to being put to use in the boiler, and
that purified water took both time and energy to create. The
purified condensate also contains a lot of sensible heat
energy which was added by the boiler to raise the water
temperature to boiling point
Cooling Towers
Cooling of condensed water from the condenser is carried
out by following methods :
• (i) Natural draught cooling towers.
• (ii) Forced draught cooling towers.
Natural draught cooling towers :
• The condensate water from the condenser to be cooled
is pumped at about 10 m above the ground into the
troughs and the nozzles at the bottom of the troughs,
sprayed it in thin sheets. These thin sheets of water
break under force of gravity and when it strikes with the
hurdles. The circulation of air for cooling the water is
induced by enclosing the heated air in the chimney. As
the heated air is lighter than the surrounding air of
atmosphere it produces a difference of pressure causing
natural draught of air for cooling of water. There are two
types of construction of natural draught cooling towers :
(a) Rectangular timber tower .
(b) Reinforced concrete hyperbolic type.
Cooling Towers
Forced draught cooling towers :
In case of large capacity thermal plants, it requires
very high rate of cooling water per hour. In such
cases, the natural draught type cooling towers are
not useful. Hence, It requires large amount of cooling
air provided by fans. The principle of forced draught
cooling towers is shown in Figure C. They are basically
natural draught cooling towers, except that motor
driven fan is also provided at the base. When a
Impeller is used at the top of the cooling tower it is
called as Induced draught cooling tower.
The forced draught cooling towers have horizontal
shaft fan on the side of the cooling tower. This fan
discharges air towards the back of tower and then it
is turned upwards by means of baffles. In the process
it cools the falling water. Fan speeds of the order of
100 rpm are used for this purpose.
The Induced draught type cooling towers are used for
large capacity Installations They use large fans with
vertical shaft located at the top of the towers, and
they pull air upwards from the sides of the cooling
tower. The warm air is exhausted at a considerable
velocity upwards after cooling the water on its way. It
requires low speed fans.
For increasing efficiency of towers, water flow should
be uniformly distributed and divided into fine droplets,
a large wetted area should be used. In order to
increase air contact time a series of baffles, shelves
etc. should be used to obstruct the flow of air.
Some picture of Bktps and ktps
Feed
waterused to
A feed water heater is a power plant
component
heater
pre-heat
water
delivered
to
a steam generating boiler. Preheating the feed water
reduces the irreversibility's involved in steam generation
and therefore improves the thermodynamic efficiency of the
system. This reduces plant operating costs and also helps to
avoid thermal shock to the boiler metal when the feed water
is introduced back into the steam cycle.
In a steam power plant (usually modeled as a
modified Rankine cycle), feed water heaters allow the feed
water to be brought up to the saturation temperature very
gradually. This minimizes the inevitable irreversibility's
associated with heat transfer to the working fluid (water).
Economizer:
The
Economizer
in
Boiler works on the principle
of Heat Transfer. Heat
transfer usually takes place
from high temperature to low
temperature. In the case
of Boilers, flue gases or
exhaust from the boiler outlet
are at high temperature and
water that needs to be
preheated is at low
temperature.
So,
this
temperature
difference
between water and flue gases
helps to increase the feed
water temperature. Depending
on
the
type
of
operations,
design
of
Economisers can be smoke
tube type or water tube type.
In smoke tube type flue gases
are inside the tubes and water
is on the shell side while in the
water tube type, water is in
the tube and flue gases are on
the shell side.
Air Pre-heater:
Air heater is an important Boiler auxiliary
which primarily preheats the combustion
air for rapid and efficient combustion in the
furnace. The air heater recovers the waste
heat from the outgoing flue gas of a Boiler
and transfers the same to the combustion
air. In a utility Boiler the flue gas leaves the
economizer at a temperature of around
3800C. As every 550C drop in flue gas
temperature improves the Boiler efficiency
by about 2.5%, having an air heater in the
downstream of economizer the Boiler
efficiency is considerably improved.
Further the air heater may also be used for
heating the air to dry the coal in the
pulverizing plant.
There are two main types of air heaters in
use; the static recuperative type and the
rotary regenerative type. In the
recuperative type the flue gas in on one
side of the surface and the air is on the
other side The heat from the flue gas istransferred to the air through the heat
transfer surface normally in form of
tubes/ plates. In the regenerative type the
gas flows through a closely packed matrix
or heat transfer element giving up heat to
the air heater elements and so raising the
temperature of the matrix. Air is then pas
through and recovers the heat. Either the
matrix or the hoaxes may be rotated to
achieve this heat transfer as a continuous
process.
Images of Air Pre-heater:
Switch Yard
• Switchyard is a switching station which is the main link between
the generating plant and the transmission system. It can be
considered as the heart of the power plant, the generated power
will only be worthy if it can be transmitted and received by the
consumers. Switchyard is a junction which carries the generated
power to the destination, it plays a major part in the security of the
system, it can control the reactive power devices which plays a
major role in power quality. It is mostly an assemblage of switches,
power circuits, breakers, and the auxiliary equipment which is used
to collect power from the generators at the power plant and then it
will be distributed to the transmission lines at a load point.
Switchyard makes available the generated power at the plant to the
people. The power generated at a power station is transmitted via a
switchyard. When there is sudden damage outside the plant
switchyard can protect the plant. A Switchyard consists of many
equipment such as Current transformer (CT), Voltage transformer
(VT), Lightning arrester (LA), Power transformers, Isolators
support structure, Circuit breaker (CB), Wave traps, Earthling
switch, Bus bar etc.
• Thus ensuring their condition and proper operation is very
important, Power Electronical has a vast experience in switchyard
equipment testing analysis erecting and commissioning of them. We
are also channel partners of ABB India. We conduct various tests
on these equipment which can be mainly categorized into two i.e.
Online Mode and Offline mode.
Some picture of Bakreswar plant
Some picture of kolaghat plant
Ash Handling Plant:
Ash handling plant in thermal power plant are used to cooled
down the ash to manageable temperature , transferred to a
disposal are or storage which is further utilized in other
industries.
Types of ash generated in TPP–
Bottom Ash – Ash generated below furnace of the thermal
power plant is called the bottom ash. The value of bottom ash
generated is around 20% of total ash. Bottom ash is mostly
coarse in nature hence to be further crushed before being
transported to ash handling plant system.
Fly ash- Around 80% of the ash generated in thermal power
plant is fly ash. It is in form of very tiny particles which is
collected via economizer hopper , air pre heater hopper and
electrostatic precipitator (ESP).
Equipment's used in ash handling plantElectrostatic precipitator , Feed/ Discharge/ Sluice Gate,
Clinker Grinder, Jet Pump, Dewatering Bin, Transfer Bin,
Storage Bin, Dry Bottom Ash Conveyor, Clinker Cooling
Conveyor, Dry Bottom Ash System, Slurry Pump.
Some picture of Bakreswar plant
Boiler Feed Water Treatment:
• What is a boiler feed water treatment system?
A boiler feed water treatment system is a system made up of several
individual technologies that address your specific boiler feed water
treatment needs. Treating boiler feed water is essential for both highand low-pressure boilers. Ensuring the correct treatment is implemented
before problems such as fouling, scaling, and corrosion occur, will go a
long way in avoiding costly replacements/upgrades down the line.
An efficient and well-designed boiler feed water treatment system should
be able to:• Efficiently treat boiler feed water and remove harmful impurities prior
to entering the boiler
• Promote internal boiler chemistry control
• Maximize use of steam condensate
• Control return-line corrosion
• Avoid plant downtime and boiler failure
• Prolong equipment service life
Boiler Feed Water Treatment:
• What does a boiler feed water treatment system typically remove?
A boiler feed water treatment system might be made up of the technologies
necessary to remove problematic dissolved solids, suspended solids, and
organic material, including any number of the following:
• Iron: either soluble or insoluble, iron can deposit on boiler parts and
tubes, damage downstream equipment, and affect the quality of certain
manufacturing processes
• Copper: can cause deposits to settle in high-pressure turbines,
decreasing their efficiency and requiring costly cleaning or equipment
change-outs
• Silica: if not removed to low levels, especially in high-pressure boilers,
silica can cause extremely hard scaling
• Calcium: can cause scaling in several forms depending on the chemistry
of the boiler feed water (e.g. calcium silicate, calcium phosphate, etc.)
• Magnesium: if combined with phosphate, magnesium can stick to the
interior of the boiler and coat tubes, attracting more solids and
contributing to scale
• Aluminum: deposits as scale on the boiler interior and can react with
silica to increase the likelihood of scaling
• Hardness: also causes deposits and scale on boiler parts and piping
• Dissolved gasses: chemical reactions due to the presence of dissolved
gases such as oxygen and carbon dioxide can cause severe corrosion on
boiler pipes and parts
Some picture of Bakreswar plant
Some picture of kolaghat plant
RESOURCES
❖Class notes
❖Wikipedia.org
❖Google.com
Conclusion:
My
vocational training in
KOLAGHAT
THERMALPOWER
STATION
and
BAKRESHWAR
THERMAL POWER PLANT has
enriched my knowledge about
generation of electric power &
also about different process
associated with it.