PowerPoint Presentation
www.energyxact.com
Sourced from, Presented by, CBIP Study materials Mr.Mridul Amin
Dep. TPPE SlideJunction Team CBIP, New Delhi Energyxact.com
www.cbip.org.in E-mail: [email protected] Technical Overview
of Thermal Power Plant
PRINCIPLE OF POWER GENERATION
A thermal power station works on the basic principle that heat
liberated by burning fuel is converted into mechanical work by
means of a suitable working fluid. The mechanical work is converted
into electrical energy by means of generator.In a steam power
station, heat is relised by burning fuel, this heat is taken by
water, which works as the working fuel. Water is converted into
steam as it receives heat in the boiler. The steam then expands in
turbine producing mechanical work, which is then converted into
electrical energy through a generator. The exhaust steam from the
turbine is then condensed in the condenser and the condensate is
there after pumped to the boiler where it again receives heat and
the cycle is repeated.The basic theoretical working cycle is of a
steam power plant is THE RANKINE CYCLE. The modern steam power
plant uses MODIFIED RANKINE CYCLE, which includes reheating,
superheating and regenerative feed water heating.
Rankine Cycle
POWER PRODUCTION PROCEDURE AT COAL BASED POWER PLANT
In the process of generation of power, following conversions
take place before the chemical energy in the form of coal finally
gets converted to electrical energy. Coal - Chemical energy
Chemical energy - Heat energy Heat energy - Kinetic energy Kinetic
energy - Mechanical energy Mechanical energy - Electrical
energy
Contd.
Coal
Chemical Energy
Super Heated Steam
Pollutants
Thermal Energy
Turbine TorqueHeat Loss In Condenser
Kinetic Energy
Electrical Energy
Alternating current in Stator
Mech. Energy Loss
ASH
Heat Loss
Elet. Energy Loss
STEAM GENERATION PRINCIPLESteam power plants operate on rankine
cycle,DM water as working fluid.Sensible heat is added in
economiser + furnaceSteam generation takes place in waterwalls.Heat
transfer in furnace and enclosed superheater takes place thru
radiation.
RANKINE CYCLERankine cycle is a heat engine with vapor power
cycle. The common fluid is water. The cycle consist of four
process:
1 to 2: isentropic expansion (steam turbine) 2 to 3: isobaric
heat rejection (condenser) 3 to 4: isentropic compression (pump) 4
to 1: isobaric heat supply (boiler)
Contd.
Boiler
Arrangement of Main BoilerThe illustration given in figure below
shows a symbolic arrangement of various accessories of a Boiler.
These accessories include:EconomiserBoiler drumDown ComersWater
wallsWater wall platen (used for Low Pressure Boilers)Primary super
heaterPlaten super heaterFinal super
heaterReheaterBurnerIgniters
Boiler structural:
The boiler structural is divided into two parts.Supporting
StructureGalleries and stair waysSupporting Structures: Boilers
supporting structure consists of a systematic arrangement of
columns stiffened with horizontal beams and vertical diagonal
bracings and comprise of low carbon steel material. It is composed
of 18 main columns and 12 auxiliary columns. The main columns
support the main boiler components viz. drum, water wall membrane,
panels, superheaters, reheaters, economisers, air preheater,
burners and galleries at various levels. The auxiliary columns,
supports the boiler platforms and other ducts coming in that
region.The total weight of supporting structures is about 970
M.T.
Galleries and stairways: Galleries and stairways around the
combustion and heat recovery areas are provided for proper approach
to the boiler. Stairways on both the side of boiler are provided.
All the floors are covered with floor gratings of required depth
for walkway and are tig welded to the structure. The total weight
of Galleries and stairway are 900 M.T.
Furnace
A boiler furnace is that space under or adjacent to a boiler in
which fuel is burned and from which the combustion products pass
into the boiler proper. It provides a chamber in which the
combustion reaction can be isolated and confined so that the
reaction remains a controlled force. In addition it provides
support or enclosure for the firing equipment
ECONOMISER
The purpose of economiser is to preheat the boiler feed water
before it is introduced into the steam drum by recovering heat from
the flue gases leaving the boiler. The economiser is located in the
boiler rear gas pass below the rear horizontal superheater. The
economiser is continuous unfinned loop type and water flows in
upward direction and gas in the downward direction.
FUNCTIONS OF ECONOMISEREconomizer saves energy by using the
exhaust gasesfrom the boiler to preheat the feed water.Economizers
are so named because they uses theenthalpy of flue gases which is
hot, but not hotenough to be used in a boiler, thereby,
recoveringuseful enthalpy and improving the boiler's efficiency
Boiler Drum
The function of steam drum is to separate the water from the
steam generated in the furnace walls and to reduce the dissolved
solid contents of the steam to below the prescribed limit of 1 ppm.
The drum is located on the upper front of boiler.
Down Comers:There are six down comers which carry water from
drum to the ring header.They are installed from outside the furnace
to keep density difference from natural circulation of water &
steam.
Water wallsPurpose is heating & evaporating the feed water
supplied to boiler to boiler drum.These are vertically tubes
connected at the top & bottom to the headers.Water wall tubes
receive water from Boiler Drum by means of down comers &
connected between drum & water walls bottom ring
header.Approximately 50% of the heat released by the combustion of
the fuel in the furnace is absorbed by the water walls.
Super Heater
There are three stages of superheater besides the side walls and
extended sidewalls. The first stage consists of horizontal
superheater of convection mixed flow type with upper and lower
banks located above economiser assembly in the rear pass. The upper
bank terminates into hanger tubes, which are connected to outlet
header of the first stage superheater. The second stage superheater
consists of pendant platen which is of radiant parallel flow type.
The third stage superheater pendant spaced is of convection
parallel flow type. The outlet temperature and pressure of the
steam coming out from the superheater are 540C and 157 Kg/Cm2
respectively for H.P.units.
Super HeaterThe super heater steam system has mainly three
sections-The low temperature super heater(LTSH),located above
Economiser.-Radiant/Platent super heater above furnace.-Convective
/ final super heaters above furnace in convective path.
1 Economiser2 Boiler Drum3 Down Comers4 Water Walls5 Platen
super heater6 Primary Super Heaters(LTSH)7 Platen Super Heaters8
Final Super Heaters9 Reheaters10 Burners11 Igniters
Radiant/Platen super heaterRadiant super heater absorb heat by
direct radiation from the furnace and are generally located at the
top of the furnace.A radiant super heater has a falling
characteristic,the steam temperature drops as the steam flow
rises.
Platen super heater
Convection super heaterConvection super heaters absorb heat
mainly by the impingement of flow of hot flue gas around the
tubes.A purely convection super heater has a rising steam
temperature charastic.
Primary super heater(LTSH)
Erection of platen super heater
Reheater
The function of reheater is to reheat the steam coming out from
high pressure turbine to a temperature of 540C. The reheater is
composed of two sections, the front pendant section and the rear
pendant section.The rear pendant section is located above the
furnace arc and the rear water wall and front pendant section is
located between the rear water hanger tubes and the superheater
platen section.
Air PreheaterThe heat carried out with the flue gases coming out
of economiser are further utilized for pre-heating the air before
supply to the combustion chamber.It is a necessary equipment for
supply of hot air for drying the coal in pulverized fuel system to
facilitate grinding and satisfactory combustion of fuel in the
furnace.
Burners
As evident from the name itself, these are used for burning
pulverized coal or oil. Every unit has a set of such burners
located at different elevations of the furnace.
Igniters
The burners are located at three elevations. Each elevation has
four oil burners and igniters. These elevations are normally known
as AB elevation, CD elevation and EF elevation. Igniters are used
for lighting the main oil gun. There are two igniter air fans
supply air for combustion of igniter oil. Mainly two types of
igniters are used.
BOILER AUXILLIARIES
Coal Bunker These are in process storage silos used for storing
crushed coal from the coal handling system. Generally, these are
made up of welded steel plates. There are totally eight bunkers,
four on each side of the boiler. Normally, there are six such
bunkers supplying coal to the corresponding mills. These are
located on top of the mills so as to aid in gravity feeding of
coal.
Coal Feeders
Each mill is provided with a drag link chain/rotary/gravimetric
feeder to transport raw coal from the bunker to the inlet chute,
leading to mill at a desired rate.
Mills
There are six mill (25% capacity each), for every 200 MW unit,
located adjacent to the furnace at '0' M level. These mills
pulverise coal to the desired fineness to be fed to the furnace for
combustion.
Hot Air
Bowl
Motor
Gear
Roller
Inner Cone
To Boiler
F.D.Fan:The forced draft fans (2 per unit - 50% capacity each)
are designed for handling secondary air for the boiler. These fans
are located at '0' M level near the PA Fan.
ID Fans :
There are two induced draft fans per boiler located between the
Electrostatic precipitator and the chimney. These fans are used for
sucking flue gas from furnace.
Wind Box
These act as distributing media for supplying secondary/excess
air to the furnace for combustion. These are generally located on
the left and right sides of the furnace while facing the
chimney.
Electrostatic precipitator
These are generally two plate type located between boiler and
the chimney. The precipitator is arranged for horizontal gas flow
and is constructed with welded steel casings.Chimney These are tall
RCC structures with single/multiple flues (one flue per 200 MW
Unit). The heights of these chimneys vary depending on the location
considerations; anywhere between 150 m. to 220 m.
Chimney
These are tall RCC structures with single/multiple flues (one
flue per 200 MW Unit). The heights of these chimneys vary depending
on the location considerations; anywhere between 150 m. to 220
m.
Seal air Fan
These are used for supplying seal air to the mills to prevent
ingress of coal dust into gear box lubrication oil. There are two
fans per boiler for 200MW units.Soot BlowersFollowing three types
of soot blowers, in requisite numbers, are provided:Long
retractable soot blowersWall blowerThe soot blowers are used for
efficient on-load cleaning of furnace, super heaters, reheaters and
regenerative air heaters.
Soot Blowers
Following three types of soot blowers, in requisite numbers, are
provided:Long retractable soot blowersWall blowerThe soot blowers
are used for efficient on-load cleaning of furnace, super heaters,
reheaters and regenerative air heaters.
Soot blower
DEARETOR:Deaerator is a device for air removal fromwater to make
it non-corrosive. Deaerator generally implies not only the
deaerator butalso the feed water tank below where deaerated water
is stored and fed to the suction of boiler feed pumps.
Deaerator and Feed water tank
Functions of deaerator: The presence of certain gases,
principally Oxygen, carbon dioxide and ammonia, dissolved in water
is generally considered harmful because of their corrosive attack
on metals,particularly at elevated temperatures function is to
remove dissolved gases from the feed water by mechanical means.
DEAERATOR
ELECTRO STATIC PRECIPITATORWhen coal is burned in the boiler,
ash is liberated and carried along with the flue gas. To arrest the
ash particles, esp is used.
FEED WATER SYSTEM:
The main equipments coming under this systemAre: Boiler feed
pump : three per unit of 50% capacity eachLocated in the '0' meter
level in the tg bay High pressure heaters: normally three in number
andAre situated in the tg bay Drip pumps : generally two in number
of 100% capacityEach situated beneath the lp heaters.
FEED WATER SYSTEM
FEED WATER SYSTEM
Feed Water PumpTo give the required pressure to the feedWater
before entering into boiler Horizontal barrel type multi stage
pumpLocated at zero meter level in tg hall.
Components of BFPBOOSTER PUMP To ensure a net positive suction
head (npsh) for main feed pump saves a costly main pump due to any
damage from cavitation typically a single-stage, centrifugal
pumpRECIRCULATION :To maintain the continuous flow of feed water
When the valve to economizer is closed
Components of BFPSUCTION STRAINERS To protect booster pump and
main pump against catastrophic failure due to entry of coarse
particlesHYDRAULIC COUPLINGUsed to transmit power from motor to
pump as per the load requirement
Feed Water Heaters Feedwater heaters are used in a regenerative
watersteam Cycle To improve thermodynamic efficiency, resulting in
aReduction of fuel consumption and thermal pollution. The boiler
feedwater is heated up by steam extracted fromSuitable turbine
ranges
LOW PRESSURE FEEDWATER HEATERSThe feedwater heaters placed
between the main condensate pumps and the boiler feedwater pumps
are named low pressure (lp) feedwater heaters. These are utube
bundle heat exchangers, which are mounted in a tube sheet and
surrounded by a steam shell.
HIGH PRESSURE FEEDWATER HEATERSThe feedwater heaters placed
between the boiler feedwater pump and the boiler are named high
pressure (hp) feedwater heaters
HP HeatersDirect contact and indirect contact type Heaters are
designed to transfer latent heat from bled steam Vent to condenser
is given to remove non condensible gases Protection of high level
is given as 80% water ingress in turbine has been due to level high
in hp heaters.
LP HeatersTurbine has been provided with noncontrolled
extractions which are utilised for heating the condensate, from
turbine bleed steam There are 3 or 4 low pressure heaters in which
lp turbine last extractions are used.
Ash Handling System:The ash handling system handles the ash by
bottom ash handling system, coarse ash handling system,fly ash
handling system, ash disposal system up to the ash disposal area
and water recovery system from ash pond and bottom ash
overflow.
Description is as follows:
A. Bottom ash handling system: Bottom ash resulting from the
combustion of coal in the boiler shall fall into the over ground,
refractory lined, water impounded, maintained level, double
vsection type/ w type steel- fabricated bottom ash hopper having a
hold up volume to store bottom ash and economizer ash of maximum
allowable condition with the rate specified. The slurry formed
shall be transported to slurry sump through pipes.
B. COARSE ASH (ECONOMIZER ASH) HANDLING: System ash generated in
economizer hoppers shall be evacuated continuously through flushing
boxes. Continuous generated economizer slurry shall be fed by
gravity into respective bottom ash hopper pipes with necessary
slope.C. AIR PRE HEATER ASH HANDLING SYSTEM: Ash generated from aph
hoppers shall be evacuated once in a shift by vacuum conveying
system connected with the esp hopper vacuum conveying system.
D. FLY ASH HANDLING SYSTEM Fly ash is considered to be collected
in esp hoppers. Fly ash from esp hoppers extracted by vacuum pumps
up to intermediate surge hopper cum bag filter for further dry
conveying to fly ash silo. Under each surge hopper ash vessels
shall be connected with oil free screw compressor for conveying the
fly Ash from intermediate surge hopper to silo.E. ASH SLURRY
DISPOSAL SYSTEM Bottom ash slurry, fly ash slurry and the coarse
ash slurry shall be pumped from the common ash slurry sump up to
the dyke areawhich is located at a distance From slurry pump
house.
Steam Turbine A steam turbine is a mechanical device that
extracts thermal energy from pressurized steam, and converts it
into useful mechanical work.
Impulse TurbinesAn impulse turbine uses the impact force of the
steam jet on the blades to turn the shaft. Steam expands as it
passes through the nozzles, where its pressure drops and its
velocity increases. As the steam flows through the moving blades,
its pressure remains the same, but its velocity decreases. The
steam does not expand as it flows through the moving blades
Velocity compounded impulse turbine
Reaction TurbinesIn the reaction turbine, the rotor blades
themselves are arranged to form convergent nozzles. This type of
turbine makes use of the reaction force produced as the steam
accelerates through the nozzles formed by the rotor.
Reaction turbine
TURBINE COMPONENTSCASINGROTORBLADESSEALING SYSTEMSTOP &
CONTROL VALVESCOUPLINGS & BEARINGSBARRING GEAR
Turbine CasingsHP Turbine Casing outer casing: a barrel-type
without axial or radial flange. Barrel-type casing suitable for
quick startup and loading.The inner casing--- cylindrical , axially
split.The inner casing is attached in the horizontal and vertical
planes in the barrel casing so that it can freely expand radially
in all directions and axially from a fixed point (HP-inlet
side).
HP Turbine Casing
IP Turbine CasingThe casing of the IP turbine is split
horizontally and is of double-shell construction.Both are axially
split and A double flow inner casing is supported in the outer
casing and carries the guide blades. Provides opposed double flow
in the two blade sections and compensates axial thrust. Steam after
reheating enters the inner casing from Top & Bottom
LP Turbine CasingThe LP turbine casing consists of a double flow
unit and has a triple shell welded casing.The shells are axially
split and of rigid welded construction.The inner shell taking the
first rows of guide blades, is attached kinematically in the middle
shell. Independent of the outer shell, the middle shell, is
supported at four points on longitudinal beams. Steam admitted to
the LP turbine from the IP turbine flows into the inner casing from
both sides.
LP Turbine Casing
RotorsHP Rotor:
The HP rotor is machined from a single Cr-Mo-V steel forging
with integral discs. In all the moving wheels of a LMZ machine
balancing holes are machined to reduce the pressure difference
across them, which results in reduction of axial thrust. In KWU
machines no balancing holes exists.All stages has integral shrouds
with pre compression.
IP RotorThe IP rotor has seven discs integrally forged with
rotor while last four discs are shrunk fit. The shaft is made of
high creep resisting Cr-Mo-V steel forging while the shrunk fit
disc are machined from high strength nickel steel forgings.Except
the last two wheels, all other wheels have shrouding riveted at the
tip of the blades. To adjust the frequency of the moving blades,
lashing wires have been provided in some stages.
LP RotorThe LP rotor consists of shrunk fit discs a shaft. The
shaft is a forging of Cr-Mo-V steel while the discs are of high
strength nickel steel forgings. Blades are secured to the
respective discs by riveted fork root fastening. In all the stages
lashing wires are provided to adjust the frequency of blades. In
the last two rows satellite strips are provided at the leading
edges of the blades to protect them against wet steam erosion.
BLADESmost costly element of turbineblades fixed in stationary
part are called guide blades/nozzles and those fitted in moving
part are called rotating/working blades.blades have three main
partsAerofoil: working part RootShroudsshroud are used to prevent
steam leakage & to guide steam to next set of moving
blades.
Three types of root arrangements are commonly used. They are (1)
T-roots: for small blades; (2) Fir Tree or serrated roots - for
longer blades; (3) Fork and Pin root: for longer blades shrunk on
disc type rotors.Integral shroud for are used for shorter blades
and shrunk fitting for larger blades. Lacing wires are also used to
dampen the vibration and to match frequencies in the longer blades.
Since in the reaction type machine the pressure drop also occurs
across the moving blades it is necessary to provide effective
sealing at the blade tips.
BEARINGS:Journal bearing---6no.SThrust bearing ---1no. Bearings
are usually forced lubricated and have provision for admission of
jacking oil
Front Bearing PedestalThe Front Bearing Pedestal is located at
the turbine side end of the turbine generator unit.Its function is
to support the turbine casing and bear the turbine rotor.It houses
the following componentsJournal bearingHydraulic turning gearMain
oil pump with hydraulic speed transducerElectric speed
transducerOver speed tripShaft vibration pick-upBearing pedestal
vibration pick-up
The bearing pedestal is aligned to the foundation by means of
hexagon head screws that are screwed in to it at several points.The
space beneath the bearing pedestal is filled with non shrinking
grout.The bearing pedestal is anchored at to the foundation by
means of anchor bolts.The anchor bolt holes are filled with
gravel,it gives a vibration dampening effect.
IP Rear Bearing PedestalArrangement:The bearing pedestal is
located between the HP and IP turbines. Its function is to support
the turbine casing and bear the HP and IP turbine rotors. The
bearing pedestal houses the following turbine components:
Journal bearing Shaft vibration pick-up Bearing pedestal
vibration pick-up Hand barring arrangement Differential expansion
measurement device
Journal BearingThe function of the journal brg.is to support the
turbine rotor.The journal brg. Consists of the upper & lower
shells,bearing cap,Spherical block, spherical support and key.The
brg shell are provided with a babbit face.Brg is pivot mounted on
the spherical support to prevent the bending movement on the
rotor.A cap which fits in to the corresponding groove in the brg
shell prevents vertical movement of the brg shell.The brg shells
are fixed laterally by key.Each key is held in position in the brg
pedestal by 2 lateral collar.
Journal BearingThe Temperature of the brg bodies is monitored by
thermocouple. Upper and lower shell can be removed without the
removal of Rotor.To do this shaft is lifted slightly by means of
jacking device but within the clearance of shaft seal.The lower
bearing shell can be turned upward to the top position and
removed.
LP TURBINERear Bearing Pedestal: The bearing pedestal is
situated between the LP turbine and generator. Its function is to
bear the LP rotor.The bearing pedestal contains the following
turbine components:Journal bearing Shaft vibration pick-up Bearing
pedestal vibration pick-up
BARRING GEARThe primary function of barring gear is rotate the
turbo generator rotors slowly and continuously During startup and
shutdown periods when changes in rotor temperature occurs >
Shaft system is rotated by double row blade wheel which is driven
by oil provided by AOPA manual barring gear is also provided with
hydraulic gearBarring speed 70-120 rpm
ESV & CV2 main stop valves and 2 control valves located
symmetrically
The main steam is admitted through the main steam inlet passing
first the main stop valves and then the control valves. From the
control valves the steam passes to the turbine casing.
Turbine is equipped with emergency stop valve to cut of steam
supply with control valves regulating steam supplyEmergency stop
valve are actuated by servo motor controlled by protection
systemControl valves are actuated by governing system through servo
motors to regulate steam supply
GENARATOR The synchronous Generator is used to Generate power by
connecting the shaft of the turbine to the generator which cuts the
magnetic flux producing Emf.
The Generator Voltage will generally 11kv to 20kv max.The
generator voltage is stepped up by connecting step up transformer
and is transmitted and is also used for Auxiliary purposes.
GENERATORTYPE AND RATING (TYPICAL FOR 500MW UNIT)
THE TURBOGENERATOR IS THREE PHASE, HORIZONTALLY MOUNTED, TWO
POLE CYLINDRICAL ROTOR TYPE DIRECTLY DRIVEN BY THE STEAM TURBINE
RUNNING AT 3000RPM. THE GENERATOR HAS FOLLOWING CONTINUOUS
RATINGS:
RATED OUTPUT500MW/588MVA
POWER FACTOR0.85 LAG
GENERATORRATED TERM. VOLT 21KV
VOLTAGE VARIATION +/-5%
FREQUENCY 50HZ
FREQ. VARIATION 47.5HZ TO 51.5HZ
COMBINED VOL. AND FREQ. VARIATION 5%(ABSOLUTE)
SHORT CIRCUIT RATIO(WITHOUT NEG.TOLE.)0.48
NEG. SEQ. CURRENT CAPABILITY 8%, 8 SEC
SHORT CIRCUIT WITHSTAND TIME 3 SEC. AT RATED MVA WITH 5% OVER
VOLTAGE
THE GENERATOR IS CONNECTED TO GENERATOR TRANSFORMER BY MEANS OF
ISOLATED PHASE BUSDUCTS.
DESIGN AND CONSTRUCTIONAL FEATURESSTATOR BODY AND CORE Totally
enclosed gas tight construction having sufficient strength and
rigidity to withstand any internal h2 explosion.
Man holes at suitable locations to facilitate inspection of back
of core and end winding area.
Stator core is made of high permeability, low loss, cold rolled
silicon sheet steel punchings which are tightly clamped and
adequately insulated.
Stampings assembled on spring core bars in an interleaved
manner.
STATOR WINDING Consists of three phase, double layer bar type
copper winding having two parallel paths.
Conductors are transposed.
Insulation epoxy thermosetting type.
Semiconducting filler and coatings to prevent slot discharge in
the gaps between the bar and slots.
Overhang portion suitably braced to withstand short circuit
forces.
ROTOR AND ROTOR WINDINGROTORCylindrical type machined from a
single alloy steel forging to give required mechanical,
metallurgical and magnetic characteristics.
Dynamically balanced and subjected to 20% over speed for 2
min.
Rotor windingConsists of coil made of hard drawn silver bearing
copper.
Epoxy glass based insulation
Retaining rings for overhang portion to take care centrifugal
forces.
CondenserThe main purpose of the condenser is to condense the
exhaust steam from the turbine for reuse in the cycle and to
maximise turbine efficiency by maintaining proper vacuum 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
cooler, the pressure ofthe exhaust steam is reduced and efficiency
ofthe cycle increases
As the operating pressure of the condenser is lowered (vacuum is
increased), the enthalpy drop of the expanding steam in the turbine
will also increase. This will increase the amount of available work
from the turbine (electrical output).
Condenser
Advantage of CondenserThe use of a condenser in a power plant is
to improve the efficiency of the power plant by decreasing the
exhaust pressure of the steam below atmosphere Another advantage of
the condenser is that the steam condensed may be recovered to
provide a source of good pure feed water to the boiler and reduce
the water softening capacity to a considerable extent A condenser
is one of the essential components of a power plant.
BY LOWERING THE CONDENSER OPERATING PRESSURE, THE FOLLOWING WILL
OCCUR: Increased turbine output Increased plant efficiency Reduced
steam flow (for a given plant output) It is therefore very
advantageous to operate the condenser at lowest possible pressure
(highest vacuum)
The Function of CondenserTo provide lowest economic heat
rejection temperature for steam To convert exhaust steam to water
for reserve thus saving on feed water requirement The use of a
condenser in a power plant is to improve the efficiency of the
power plant by decreasing the exhaust pressure of the steam below
atmosphere.
To condense exhaust steam from turbine To maintain vacuum for
better efficiency Remove non condensable gasses from the cycle
Provide reserve for cep suction Acts as a low pressure sink for
cycle drains, vents etc.
Cooling Towers A Condenser needs huge quantity of water to
condense the steamTypically a 2000MW plant needs about 1500MGallon
of water.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.High of the cooling tower may
be 150 m
CONDENSATE EXTRACTION PUMP (CEP)The condensate extraction pump
(cep) is a centrifugal, vertical pump, consisting of the pump body,
the can, the distributor housing and the driver lantern A rising
main of length depending upon npsh available, is also provided, the
pump body is arranged vertically in the can and is attached to the
distributor body with the rising mainThe rotor is guided in
bearings lubricated by the fluid pumped, is suspended from the
support bearing, which is located
CEP Pump
Function of CEPThe function of these pumps is to pumps out the
condensate to the deaerator thru' ejectors, gland steam cooler, and
L.P. Heaters.These pumps have four stages and since the suction is
at a negative pressure, special arrangements have been made for
providing sealing.
OPERATION MECHANISMThe coal is brought and crushed to
powder,This is feed to Boiler for production heat In Boiler the
water is converted to steamIn superheater the content is removed
from the steam and that steam is called super heated steamThe
superheated steam rotates the shaft of the high pressure turbineThe
Exhausted steam is sent to preheater and the steam then rotates the
intermediate pressure(IP) TurbineThe steam from the IP turbine is
then feed to low pressure turbine The turbine shaft is connected to
the Generator ,which produces Electric PowerThe power generation is
then Transmitted.
Thank you for your attention!For more information please visit
our site:www.energyxact.com
