Thermal power plant Khedr, Hisar, Haryana
-
Upload
eesha-gupta -
Category
Sports
-
view
5.193 -
download
3
Transcript of Thermal power plant Khedr, Hisar, Haryana
PROJECT:FAMILIARIZATION OF POWER PLANT ALONG WITH ITS VARIOUS ASPECTS
Under the guidance of Mrs. Santosh Sahran AEE/C&I-I
Submitted by:Eesha GuptaECE-505-2K9
HPGCL (Haryana Power Generation Corporation Limited) was incorporated
as company on March 17, 1997 and was given the responsibility of operating and maintenance of State's own generating projects. One of them is Rajiv Gandhi Thermal Power Plant (RGTPP), Khedar.
It was commissioned on August 24, 2010.
It has two units each with a generating power of 600 MW. This means that total generation of the plant per day is 1200
MW.
HOW DOES ELECTRICITY REACH THE CUSTOMER
At present 60% of total electricity production in India is from Coal Based Thermal Power Station. A coal based thermal power plant
converts the chemical energy of the coal into electrical energy. This is achieved by raising the steam in the boilers, expanding it through
the turbine and coupling the turbines to the generators which converts mechanical energy into
electrical energy.
WHY COAL ?
•Abundantly available• Low cost
• Technology for generation well developed
• Easy to mine, transport and store
• Economically possible to set up coal based plants
• Produces high energy upon combustion
MAJOR
COAL MINES IN
INDIA
But there are certain disadvantages related to coal
• Non-renewable and fast depleting• Lowest energy density per unit volume,
meaning that the amount of energy generated per cubic meter is lower than any
other fossil fuel• High coal transportation costs due to the
bulk of coal• Produces large number of pollutants
• Coal dust is an extreme explosion hazard, so transportation and storage must take special
precautions to mitigate this danger
Coal
Chemical Energy
Super Heated Steam
Pollutants
Thermal Energy
Turbine Torque
Heat Loss In Condenser
Kinetic Energy
Electrical Energy
Alternating current in Stator
Mech. Energy LossASH
Heat
Loss
Elec. Energy Loss
COAL TO ELECTRICITY……..
BASIC OPERATION
BASIC OPERATION• The coal is brought and crushed to powder. This
is feed to furnace for producing heat• In Boiler drum the water is converted to steam.• In Super heater the moisture content is removed
from the steam and that steam is called super heated steam
• The superheated steam rotates the shaft of the High pressure turbine
• The Exhausted steam is sent to reheater and the steam then rotates the Intermediate pressure(IP)
Turbine•The steam from the IP turbine is then feed to low
pressure turbine.• The turbine shaft is connected to the Generator,
which produces Electric Power.• The power generated is then Transmitted.
RANKINE CYCLE – THE WORKING PRINCIPLE OF THERMAL POWER PLANTS ALL OVER THE WORLD
Starting at 1, the water at room temperature is boiled at constant
temperature in the boiler. This process has a T constant for it is the boiling of water which takes at a constant temperature.
Here we are increasing the entropy of by phase change. The end product is steam.
The steam must be heated to higher temperatures. This phase is called super
heater and this phase is mainly executed in ‘super heater’. The source of heat for the
super heater is the hot flue gases obtained in the boiler after burning coal. This
explains the phase 2-3 in the T-S curve. in the next process, the super heated steam is
allowed to expand in the turbine. As, the high pressure steam is allowed through a
small nozzle ,steam acquires kinetic energy.
This kinetic energy of the steam will exert required force on the turbine blades. This
process is a constant entropy process. Now the output of the turbine is low pressure
and low temperature steam. This accounts for the phase 3-4 of the cycle. Now steam is changed to hot water in condenser without any temperature change. This accounts for the phase 4-5 of the cycle. The step 5-6 is a
pump which is used to circulate water. During this process, a little temperature
change can be observed. Finally, the cooled water cannot be directly sent into boiler.
Hence, the water should be heated to higher temperature. This is done in economizer
which uses heat from flue gases. Thus this accounts for the 6-1 phase of the Rankine
cycle.
SIMPLIFIED DIAGRAM
1. Cooling tower2. Cooling water pump
3. Transmission line4. Step-up transformer5. Electrical generator
6. Low pressure steam turbine7. Condensate pump8. Surface condenser
9. Intermediate pressure steam turbine
10. Steam Control valve11. High pressure steam turbine
12. Deareator13. Feed heater/heater
14. Coal conveyor15. Coal hopper
16. Coal pulverizer17. Boiler steam drum
19. Superheater20. Forced draught (draft)
fan21. Reheater
22. Combustion air intake23. Economiser
24. Air preheater25. Precipitator
26. Induced draught (draft) fan
27. Flue gas stack
COMPONENTS
COAL HANDLING SYSTEM
It contains many components:
• Coal wagon• Wagon tippler• coal hopper• crusher
• magnetic separator• dryer
• coal mill• pulveriser• storage
Coal hopper
Coal mills
Coal bunker
Back to slide no. 43
BOILER
A Boiler or steam generator essentially is a container into which water can be fed and steam can be taken out at desired pressure (172-180 kg), temperature (540°C) and flow. This calls for application of heat on the container. For that the boiler should have a facility to burn a fuel and release the heat. The functions of a boiler thus can be stated as:-• To convert chemical energy of the fuel into heat energy• To transfer this heat energy to water for evaporation as well to steam for superheating.
• Light diesel oil (LDO)• Heavy fuel oil (HFO)
Light diesel oil is fuel of intermediate viscosity. Preheating may be necessary in some equipment for burning and, in colder climates, for handling. It is also costly. Heavy fuel oil is a fuel more viscous than Light diesel oil but intended for similar purposes. Preheating is usually necessary for burning and, in colder climates, for handling. It is less costly than LDO
KINDS OF OIL USED IN FURNACE
FLAME MONITOR
FURNACE AND ITS ALLEVATION POINTS
There are five alleviation points in a furnace from where oil firing is done. Initially LDO is used at BC and FG. Thereafter HFO is
used at remaining levels.
Combustion Reactions
Carbon reaction 2C + O2 =2CO [Eco=60kJ/mol]C + O2 =CO2 [Eco2=140kJ/mol]
Reaction at 1200oC4C + 3O2 =2CO + 2CO2 (Ratio 1:1)
Reaction at 1700oC3C + 2O2 = 2CO + CO2 (Ratio 2:1)
Hydrogen reaction2H2 + O2 = 2H2O 61095 BTU/lb
Sulfur reactionS + O2 = SO2 3980 BTU/lb
(undesirable)
Super heater : The steam is super heated in order to make it
hold more energy and transfer it to the turbine. This job is accomplished by the super heater.
Super heater is showed in the boiler schematic. The flue gases coming out of the
boiler are used to super heat the steam.
Economizer : The water entering into the boiler must have a
temperature compatible with the boiler temperature. So, the heat left with the flue gases after superheater is used to heat the
water in the economizer. The economizer has convoluted tubes in which water flows and the
flue gases flow over these tubes in a closed structure.
ReheaterPower plant furnaces may have a reheater section containing tubes heated by hot flue gases outside the tubes. Exhaust steam from the high pressure turbine is rerouted to go inside the reheater tubes to
pickup more energy to go drive intermediate or lower pressure turbines.
Ash handling systemThe disposal of ash from a large capacity power station is of same
importance as ash is produced in large quantities. Ash handling is a major problem.
i) Manual handling: The ash is collected directly through barrows from the ash outlet door from the boiler into the container from
manually.
ii) Mechanical handling: Mechanical equipment is used for ash disposal, mainly bucket elevator, belt conveyer.
iii) Electrostatic precipitator: From air preheater this flue gases (mixed with ash) goes to ESP. The precipitator has plate banks (A-F)
which are insulated from each other between which the flue gases are made to pass. The dust particles are ionized and attracted by charged
electrodesBack to slide 43
TURBINES
In thermal Power Plant generally 3 turbines are used to increase the efficiency.
High Pressure Turbine(HPT): The superheated steam is directly fed to this turbine to rotate it.
Intermediate Pressure Turbine(IPT): The out put from the HPT is reheated in a reheater(RH) and used to rotate IPT .
Low Pressure Turbine(LPT): The Exhausted steam from the IPT is directly fed to rotate the shaft of LPT.
*All the turbines are connected to a single shaft which is connected to the Generator.
GENERATORSThe Synchronous Generator is used to Generate power by
connecting the shaft of the Turbine to the shaft of the generator which cuts the magnetic flux producing mf.
The Generated Voltage will generally 11KV to 20 KV max. here 20KV
The Generated Voltage is stepped up by connecting Step up transformer (here 400KV) and is transmitted and is also used for
Auxiliary purposes.
Unit Auxiliary Transformer: This transformer is used to step down the produced voltage and use for Auxiliary purpose.
BOILER FEED PUMP
Boiler feed pump is a multi stage pump provided for pumping feed water to economiser. BFP is the biggest
auxiliary equipment after Boiler and Turbine. It consumes about 4 to 5 % of total electricity generation.
AIR PREHEATER
The heat carried out with the flue gases coming out of economiser are further utilized for preheating the air before supplying to the combustion chamber. It is a
necessary equipment for supply of hot air for drying the coal in pulverized fuel systems to facilitate grinding and
satisfactory combustion of fuel in the furnace
CONDENSOR
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 of the exhaust steam is reduced and efficiency of the cycle increases. Below shown is surface
condensor which is used in RGTPP, Khedar
COOLING TOWER
The cooling tower is a semi-enclosed device for evaporative cooling of water by contact with air. The hot water coming out
from the condenser is fed to the tower on the top and allowed to tickle in form of thin sheets or drops. The air flows from bottom of the tower or perpendicular to the direction of water flow and
then exhausts to the atmosphere after effective cooling.
COOLING TOWER
DEAERATORIt is used to remove air which is entrapped in the water
molecules. It is very important part because the entrapped air affects boiler drum badly and leads to
corrosion.
DEAERATOR
Principle behind deareation: gas solubility decreases as temperature rises till saturation temperature is
achieved. Therefore when steam interacts with water it rises the temperature of water till saturation
temperature.
There are total three pumps attached to Deareator. They are Motor Driven Boiler Feed Pump (MDBFP) on standby and two TDBFP (Turbine Driven Boiler Feed
Pump). MDBFP is costly and uses electricity for its operation. Therefore it is used in the starting only. TDBFP is very economical and is turbine driven. Tappings are taken from HP turbines and LP turbines. Steam from those
tappings is used to drive TDBFP.
FEED HEATER
Two types of feed heater are there:High pressure heaterLow pressure heater
H P Heater is installed after Boiler feed pump and it heats the feed water by exchanging heat with the steam that is extracted from
the H.P. Turbine from different stages at different pressure.
L P heater is installed after condensate extraction pump and in the same way it heats the water but it takes the steam
extraction from the L.P. turbine.
Atmospheric air from PA fan is mixed with coal and fed in
the furnace. FD fan supports combustion
ID fan is the outlet or exhaust. Already present air
in furnace is sucked by ID fan and thrown out.
FANS
Three kinds of fans are there:• Primary air fan• Forced draft fan• Induced draft fan
PRIMARY AIR FAN CYCLE
Cool air
Cool air
FORCED DRAFT FAN
INDUCED DRAFT FAN
MAJOR EVENTS OF PLANT:
• Coal flow• Water flow• Steam flow• Ash handling
WATER FLOW
STEAM FLOW
SWAS DEPARTMENT(Steam and Water Analysis System)
Different samples of water and steam are taken for testing its various aspects.
• Silica analyzers• Phosphate analyzers• Chloride analyzers• Hydrazine analyzers• Sodium analyzers• Cation conductivity• Specific conductivity• Ph transmitters
• Dissolved oxygen transmitters
There are ten HIS (Human Interface Station) in each unit. These HIS are:• Engineering station (one)
• Historians (two)• SOE – Sequence of Events (one)• Performance calculation (one)• Operation systems (five)
In addition to HIS, we have twenty three FCS
(Field Control Station) in each unit.
DCS SYSTEM
The termination pannel contains electronic cards which are responsible for every type of
communication process.
• AI card (analog input)• AO card (analog output)• DI card (digital input)• DO card (digital output)
MEASUREMENTS TAKEN IN POWER PLANT
• Temperature• Pressure• Level
• Analysis of water, steam and flue gases• Others
TEMPERATURE MEASUREMENTS:
•Steam at superheater inlet and outlet•Feed water at economizer inlet•Air preheater•Reheater outlet•Furnace•Coal mill inlet and outlet•P A fan, I D fan•L P, H P heaters
PRESSURE MEASUREMENTS:
•Boiler•Furnace•Coal mill•Furnace•Boiler drum
STEAM MEASUREMENTS:
•Reheated steam at outlet of reheater (LHS)•Reheated steam at outlet of reheater (RHS)•Saturated steam (RHS)•Saturated steam (LHS)•Super heated steam (RHS)•Super heated steam (LHS)
WATER MEASUREMENTS:
•Feed water at economizer inlet•Boiler water (left side)•DM water•HP heater drain•LP heater drain•Electric generator cooling water•Deareator