nspcl presentation
TRANSCRIPT
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NSPCL
A JOINT VENTURE OF NTPC and SAIL
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NTPC Ltd formed a joint venture with SAIL on 50:50 basis
in March, 2001 in the name NTPC-SAIL Power Company
Private Limited (NSPCL). NSPCL took over captive power
plant-II located at Durgapur Steel Plant (2X60 MW) and
Rourkela Steel Plant (2X60 MW) from SAIL.
THE COMPANY AND ITS OBJECTIVE
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To supply power to Bhilai, Durgapur and Rourkela Steel Plants of Steel Authority of India
Ltd. (SAIL) on captive basis from its coal based captive power plants –II at Bhilai
(Chhattisgarh) 2X30 MW + 1X14 MW, Durgapur (West Bengal) 2X60 MW and Rourkela
(Orissa) 2X60 MW. To meet additional captive power requirement of Bhilai Steel Plant and
other units of SAIL, NSPCL commissioned Bhilai CPP-II Expansion Power Project
(2X250MW) during 2008-09 and commercialized the units during 2009-10. From the
expansion plant, NSPCL is supplying power to the beneficiaries viz. Union Territory of
Dadra & Nagar Haveli , Union Territory of Daman & Diu, Chhattisgarh and Bhilai Steel
Plant / SAIL in the western region.
OBJECTIVE
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1.Coal handling plant2.Pulverising plant3.Draft fans4.Boiler5.Ash handling plant6.Turbine7.Condenser8.Cooling towers9.Feedwater heater10.Economiser11.Air-Preheater
MAIN AND AUXILIARY EQUIPMENTS
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Coal handling plant
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Use of F- grade coal(3500kcal/kg) Process involved are:1.Seperation of metal2.Stone collection3.Magnetic separator4.Crushing to a size of 20mm5.storage
Details of coal handling plant
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The difference between atmospheric pressure and the pressure existing in the furnace or flue gas passage of a boiler is termed as draft.
There are 2 types of draft fans used in thermal plants:-
1. Induced draft2. Forced draft
DRAFT SYSTEM
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Placed at the outlet of boiler
Exhausts all gaseous combustion products or flue gas by creating negative pressure
More susceptible to erosion and corrosion
Induced draft
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Forced draft
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Supply the air necessary for combustion pushing the air through combustion chamber to the furnace
Most efficient fans in power plants
These are centrifugal fans, uses variable pitch axial fans
Function of FD
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BOILERS
Definition: An enclosed vessel where heating of fuel or gas takes place
Place where differential heating takes place
To maximize efficiency water tubes are constructed
Water tubes absorb the heat
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Water tube boilers Corner fixed Drum type Natural recirculation Tilted firing superheated Vertically downward expansion
TYPES OF BOILERS
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Water tube boiler
A pressure of 140kg/cm2 can be obtained easily.
Increases boiler efficiency
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Definition: It is a water to steam separator
Water entering into the drum has Temp. about 3500 C and pressure about170kg/cm2
It is placed 60m high
It includes natural recirculation process
If pressure >190kg/ cm2 ,then forced recirculation is done
Boiler drum(steam cycle)
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Boiler drum
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Ash is the residue remaining after the coal is incinerated
SiO2, Al2O3, Fe2O3, CaO , MgO are the components in ash
Ash generated in power plant is about 30-40% of total coal consumption
2 type of ashes:1. Fly Ash -Around 80% is the value of fly ash
generated2. Bottom ash -Bottom ash is 20% of the ash
generated in coal based power stations.
Ash handling plant
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Bottom Ash Handling System: Bottom ash resulting from the combustion of coal in the boiler
Further the slurry is passed through pipes
Coarse Ash (Economizer Ash) handling System: Ashes generated in economizer
Fly Ash Handling System: Fly ash is considered to be collected in ESP Hoppers.
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TURBINES Turbines form the heart of power plants Generally to maximize the efficiency, steam
has to be expanded Work increases in stages use of HPT,LPT and intermediate turbines
(IPT)- multi stage turbines HPT and IPT are single flow
turbines(expansion of steam on only 1 side) having 24 stages.
LPT is double flow turbine with 8 stages.
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Flow diagram
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HPT Details
Inlet pressure (kg/cm2 )
Inlet temperature(o
C)
Outlet pressure(kg/cm2 )
Outlet temperature(o C)
35 350 147 540
Low Pressure Turbine
Outlet pressure Outlet temperature
8-10 kg/cm2 <500 o C
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IMPULSE TURBINE & REACTION TURBINE
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Have fixed nozzle that orients the flow into high speed jets
High kinetic energy, results in shaft rotation
Drop in the pressure from inlet to outlet increases the expansion rate of steam
Steam velocity increases
There is a loss of energy due to high exit velocity which is called as carry over velocity
EXPLANATION (IMPULSE TURBINE)
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A condenser is a device or unit used to condense a substance from its gaseous to its liquid state, typically by cooling it.
The latent heat is given up by the substance, and will transfer to the condenser coolant.
In thermal Power plant we use surface condenser
condenser
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CROSS-SECTION OF SURFACE CONDENSER
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Cooling towers are heat removal devices used to transfer process waste heat to the atmosphere
Classified into two:1.HVAC cooling tower2.Industrial cooling tower
HVAC(heating , ventilation &air-conditioning)- HVAC use of a cooling tower pairs the cooling tower with a water-cooled chiller or water-cooled condenser.
Industrial Cooling tower- Industrial cooling towers can be used to remove heat from various sources such as machinery or heated process material.
The primary use- cooling towers is to remove the heat absorbed in the circulating cooling water systems used in power plants.
Cooling towers
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An air preheater absorbs waste heat from flue gas, then transfers this heat to incoming cold air.
Two types of air preheaters are used: bisector (one air stream per air heater) and trisector ( two air streams per air heater).
The trisector incorporates both primary and secondary air within one housing.
AIR - PREHEATER
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Control room