Report @Ntpc

8/22/2019 Report @Ntpc

1/34

PRESENTATION REPORT ON

Industrial Training at

NTPC Badarpur Thermal Power Station

( ISO 9001/ ISO 14001 Power Station )

Submitted By:

Prashant kumar singh (ME/11/727)

VT 1776MECHANICAL ENGINEERING

Department of Mechanical Engineering

SHRI BALWANT INSTITUTE OF TECHNOLOGYApproved by AICTE, Min of HRD, Govt of India & DTE, Govt of Haryana

Affiliated to DCR University of Science and Technology,

Murthal,Sonepat-131001, Haryana


2/34

ABSTRACT

Training at BTPS : I was appointed to do a 4 week training at the Badarpur

Thermal Power Station under the National Thermal Power Corporation from

1stJuly 2013 to 27th July 2013 . I was assigned to visit various divisions of the

plant, which were

BMD

1. Boiler Maintenance Department-I (BMD-I)2. Boiler Maintenance Department-II (BMD-II)3. Boiler Maintenance Department-III (BMD-III) .

PAM

1. Control Structure Pump House.2. Water treatment Plant.3. Cooling Towers.4. Ash Slurry Pump House.5. Air Compressor House.

TMD

1. Turbine Maintenance Department.This report has been made by my experience at BTPS. The material in this

report has been gathered from my textbook, senior student reports and

trainers manuals and power journals provided by training department. The

specification and principles are as learned by me from the employees of

each division of BTPS.

ii


3/34

TABLE OF CONTENTS

1.INTRODUCTION:i. About NTPC.ii. Badarpur Thermal Power Station .iii. Powerplant .

2. DESCRIPTION:i. Rankine Cycle

ii. A COAL powered station .iii .Coal to power .

iv. BMD .v. PAM.vi. TMD.

3. INFERENCES4. REFERENCES

1


4/34

INTRODUCTION

2


5/34

About NTPC

NTPC Limited (formerly National Thermal Power Corporation) is theplant largestIndian state-owned electric utilities company based in New

Delhi, India. It is listed in Forbes Global 2000for 2012 ranked at 337th in theworld. With an electric power generating capacity of 41,184 MW, NTPC hasembarked on plans to become a 128,000 MW company by 2032. It was

founded on 7 November 1975. On 21 May 2010, NTPC was conferred

Maharatna status by the Union Government of India. The total installedcapacity of the company is 36,514 MW (including JVs) with 16 coal-basedand seven gas-based stations, located across the country. In addition under

JVs (joint ventures), six stations are coal-based, and another station usesnaphtha/LNG as fuel. By 2017, the power generation portfolio is expected to

have a diversified fuel mix with coal-based capacity of around 27,535 MW,

3,955 MW through gas, 1,328 MW through hydro generation, about 1,400MW from nuclearsources and around 1,000 MW from Renewable EnergySources (RES). NTPC has adopted a multi-pronged growth strategy which

includes capacity addition through green field projects, expansion of existingstations, joint ventures, subsidiaries and takeover of stations.

NTPC has been operating its plants at high efficiency levels. Although the

company has 19% of the total national capacity it contributes 29% of total

power generation due to its focus on high efficiency. NTPCs share at 31Mar 2001 of the total installed capacity of the country was 24.51% and it

generated 29.68% of the power of the country in 200809. Every fourth

home in India is lit by NTPC. As at 31 Mar 2011 NTPC's share of thecountry's total installed capacity is 17.18% and it generated 27.4% of thepower generation of the country in 201011. NTPC is lighting every third

bulb in India. 170.88BU of electricity was produced by its stations in thefinancial year 20052006. The Net Profit after Tax on 31 March 2006 was

58.202 billion. Net profit after tax for the quarter ended 30 June 2006

was 15.528 billion, which is 18.65% more than that for the same quarterin the previous financial year. Pursuant to a special resolution passed bythe Shareholders at the Companys Annual General Meeting on 23

September 2005 and the approval of the Central Government undersection 21 of the Companies Act, 1956, the name of the Company"National Thermal Power Corporation Limited" has been changed to

"NTPC Limited" with effect from 28 October 2005. The primary reason

for this is the company's foray into hydro and nuclear based powergeneration along with backward integration by coal mining.

3
https://en.wikipedia.org/wiki/Indiahttps://en.wikipedia.org/wiki/Electric_utilitieshttps://en.wikipedia.org/wiki/Forbes_Global_2000https://en.wikipedia.org/wiki/Maharatnahttps://en.wikipedia.org/wiki/Coalhttps://en.wikipedia.org/wiki/Natural_gashttps://en.wikipedia.org/wiki/Naphthahttps://en.wikipedia.org/wiki/Liquified_natural_gashttps://en.wikipedia.org/wiki/Hydroelectric_powerhttps://en.wikipedia.org/wiki/Nuclear_powerhttps://en.wikipedia.org/wiki/Renewable_energyhttps://en.wikipedia.org/wiki/Renewable_energyhttps://en.wikipedia.org/wiki/Renewable_energyhttps://en.wikipedia.org/wiki/Renewable_energyhttps://en.wikipedia.org/wiki/Nuclear_powerhttps://en.wikipedia.org/wiki/Hydroelectric_powerhttps://en.wikipedia.org/wiki/Liquified_natural_gashttps://en.wikipedia.org/wiki/Naphthahttps://en.wikipedia.org/wiki/Natural_gashttps://en.wikipedia.org/wiki/Coalhttps://en.wikipedia.org/wiki/Maharatnahttps://en.wikipedia.org/wiki/Forbes_Global_2000https://en.wikipedia.org/wiki/Electric_utilitieshttps://en.wikipedia.org/wiki/India


6/34

Badarpur Thermal Power Stationis located atBadarpurarea in NCTDelhi. The power is one of the coal based power plants ofNTPC. The

National Power Training Institute (NPTI) forNorth India Region underMinistry of Power,Government of India was established at Badarpur in1974, within the Badarpur Thermal power plant (BTPS) complex.

Power Plant

The Badarpur Thermal Power Station has an installed capacity of 705

MW. It is situated in south east corner of Delhi on Mathura Road near

Faridabad. It was the first central sector power plant conceived in India,in 1965. It was originally conceived to provide power to neighbouringstates of Haryana, Punjab, Jammu and Kashmir, U.P., Rajasthan, and

Delhi. But since year 1987 Delhi has become its sole beneficiary. It wasowned and conceived by Central Electric Authority. Its construction wasstarted in year 1968, and the First unit was commissioned in 26 July 1973.

The coalfor the plant is derived from the Jharia Coal Fields. This was

constructed under ownership of Central Electric Authority, later it wastransferred to NTPC. It receives its water from the Agra Canal .

Efficiency :- The energy efficiency of a conventional thermal powerstation, considered usable energy produced as a percent of the heating

value of the fuel consumed, is typically 33% to 48%. As with all heatengines, their efficiency is limited, and governed by the laws ofthermodynamics. By comparison, mosthydropower stations in the UnitedStates are about 90 percent efficient in converting the energy of falling

water into electricity. The energy of a thermal not utilized in powerproduction must leave the plant in the form of heat to the environment.This waste heatcan go through a condenserand be disposed of with

cooling wateror in cooling towers. If the waste heat is instead utilized for

district heating, it is calledco-generation. An important class of thermalpower station are associated with desalinationfacilities; these are

typically found in desert countries with large supplies ofnatural gas andin these plants, freshwater production and electricity are equallyimportant co-products .

Electricity Costs : The direct cost of electric energy produced by a thermalpower station is the result of cost of fuel, capital cost for the plant,operator labour, maintenance, and such factors as ash handling and

disposal. Indirect, social or environmental costs such as the economicvalue of environmental impacts, or environmental and health effects of the

4
http://en.wikipedia.org/wiki/Badarpur,_Delhihttp://en.wikipedia.org/wiki/National_Capital_Territory_of_Delhihttp://en.wikipedia.org/wiki/National_Capital_Territory_of_Delhihttp://en.wikipedia.org/wiki/Coalhttp://en.wikipedia.org/wiki/National_Thermal_Power_Corporationhttp://en.wikipedia.org/wiki/National_Power_Training_Institutehttp://en.wikipedia.org/wiki/North_Indiahttp://en.wikipedia.org/wiki/Ministry_of_Power_%28India%29http://en.wikipedia.org/wiki/Government_of_Indiahttp://en.wikipedia.org/wiki/Coalhttp://en.wikipedia.org/w/index.php?title=Central_Electric_Authority&action=edit&redlink=1http://en.wikipedia.org/wiki/Heating_valuehttp://en.wikipedia.org/wiki/Heating_valuehttp://en.wikipedia.org/wiki/Thermodynamichttp://en.wikipedia.org/wiki/Hydroelectricityhttp://en.wikipedia.org/wiki/Waste_heathttp://en.wikipedia.org/wiki/Surface_condenserhttp://en.wikipedia.org/wiki/Cooling_waterhttp://en.wikipedia.org/wiki/Cooling_towerhttp://en.wikipedia.org/wiki/District_heatinghttp://en.wikipedia.org/wiki/Co-generationhttp://en.wikipedia.org/wiki/Desalinationhttp://en.wikipedia.org/wiki/Natural_gashttp://en.wikipedia.org/wiki/Natural_gashttp://en.wikipedia.org/wiki/Desalinationhttp://en.wikipedia.org/wiki/Co-generationhttp://en.wikipedia.org/wiki/District_heatinghttp://en.wikipedia.org/wiki/Cooling_towerhttp://en.wikipedia.org/wiki/Cooling_waterhttp://en.wikipedia.org/wiki/Surface_condenserhttp://en.wikipedia.org/wiki/Waste_heathttp://en.wikipedia.org/wiki/Hydroelectricityhttp://en.wikipedia.org/wiki/Thermodynamichttp://en.wikipedia.org/wiki/Heating_valuehttp://en.wikipedia.org/wiki/Heating_valuehttp://en.wikipedia.org/w/index.php?title=Central_Electric_Authority&action=edit&redlink=1http://en.wikipedia.org/wiki/Coalhttp://en.wikipedia.org/wiki/Government_of_Indiahttp://en.wikipedia.org/wiki/Ministry_of_Power_%28India%29http://en.wikipedia.org/wiki/North_Indiahttp://en.wikipedia.org/wiki/National_Power_Training_Institutehttp://en.wikipedia.org/wiki/National_Thermal_Power_Corporationhttp://en.wikipedia.org/wiki/Coalhttp://en.wikipedia.org/wiki/National_Capital_Territory_of_Delhihttp://en.wikipedia.org/wiki/National_Capital_Territory_of_Delhihttp://en.wikipedia.org/wiki/Badarpur,_Delhi


7/34

complete fuel cycle and plant decommissioning, are not usually assignedto generation costs for thermal stations in utility practice, but may form

part of an environmental impact assessment.

THERMAL POWER STATION :-

Basic operation or cycle of operation of a thermal power station : -In fossil-fueled power plants, steam generator refers to a furnace that

burns the fossil fuel to boil water to generate steam. In the nuclear plant

field, steam generator refers to a specific type of large heat exchangerused in a pressurized water reactor (PWR) to thermally connect the

primary (reactor plant) and secondary (steam plant) systems, whichgenerates steam. In a nuclear reactor called a boiling water reactor(BWR), water is boiled to generate steam directly in the reactor itself and

there are no units called steam generators. In some industrial settings,there can also be steam-producing heat exchangers calledheat recoverysteam generators (HRSG) which utilize heat from some industrial process.The steam generating boiler has to produce steam at the high purity,

pressure and temperature required for the steam turbine that drives theelectrical generator.

Geothermal plants need no boiler since they use naturally occurring steamsources. Heat exchangers may be used where the geothermal steam is verycorrosive or contains excessive suspended solids.

5
http://en.wikipedia.org/wiki/Boiler_%28steam_generator%29http://en.wikipedia.org/wiki/Nuclear_powerhttp://en.wikipedia.org/wiki/Steam_generator_%28nuclear_power%29http://en.wikipedia.org/wiki/Heat_exchangerhttp://en.wikipedia.org/wiki/Pressurized_water_reactorhttp://en.wikipedia.org/wiki/Boiling_water_reactorhttp://en.wikipedia.org/wiki/Heat_recovery_steam_generatorhttp://en.wikipedia.org/wiki/Heat_recovery_steam_generatorhttp://en.wikipedia.org/wiki/Geothermal_powerhttp://en.wikipedia.org/wiki/Geothermal_powerhttp://en.wikipedia.org/wiki/Heat_recovery_steam_generatorhttp://en.wikipedia.org/wiki/Heat_recovery_steam_generatorhttp://en.wikipedia.org/wiki/Boiling_water_reactorhttp://en.wikipedia.org/wiki/Pressurized_water_reactorhttp://en.wikipedia.org/wiki/Heat_exchangerhttp://en.wikipedia.org/wiki/Steam_generator_%28nuclear_power%29http://en.wikipedia.org/wiki/Nuclear_powerhttp://en.wikipedia.org/wiki/Boiler_%28steam_generator%29


8/34

Rankine Cycle

Rankine cycle is the idealized cycle for steam power plants. This cycle isshown on p-v,

T-v, h-s, diagram in the above figures. It consists of following processes:of Technology

Process 1-4:Water from the condenser at low pressure is pumped into the

boiler athigh pressure. This process is reversible adiabatic.

Process 4-5:Water is converted into steam at constant pressure by theaddition of heatin the boiler.Process 6-3:Bleed water taken for regeneration .

Process 5-7:Reversible adiabatic expansion of steam in the steam turbine.Process 7-1:Constant pressure heat rejection in the condenser to convertcondensateinto water.

The steam leaving the boiler may be dry and saturated, wet or superheated.

6


9/34

A Coal powered station

Typical diagram of a coal-f ir ed thermal power station

1. Cooling tower 10. Steam Control valve 19. Superheater

2. Cooling water pump 11. High pressure steam turbine 20. Forced draught (draft) fan

3. transmission line (3-phase) 12. Deaerator 21. Reheater

4. Step-up transformer(3-phase) 13. Feedwater heater 22. Combustion air intake

5. Electrical generator(3-phase) 14. Coal conveyor 23. Economiser

6. Low pressure steam turbine 15. Coal hopper 24. Air preheater

7. Condensate pump 16. Coal pulverizer 25. Precipitator

8. Surface condenser 17. Boiler steam drum 26. Induced draught (draft) fan

9. Intermediate pressure steam

turbine18. Bottom ash hopper 27. Flue gas stack

7
http://en.wikipedia.org/wiki/Cooling_towerhttp://en.wikipedia.org/wiki/Control_valvehttp://en.wikipedia.org/wiki/Superheaterhttp://en.wikipedia.org/wiki/Steam_turbinehttp://en.wikipedia.org/wiki/Centrifugal_fanhttp://en.wikipedia.org/wiki/Electrical_power_transmissionhttp://en.wikipedia.org/wiki/Three-phasehttp://en.wikipedia.org/wiki/Deaeratorhttp://en.wikipedia.org/wiki/Transformerhttp://en.wikipedia.org/wiki/Three-phasehttp://en.wikipedia.org/wiki/Feedwater_heaterhttp://en.wikipedia.org/wiki/Combustionhttp://en.wikipedia.org/wiki/Electrical_generatorhttp://en.wikipedia.org/wiki/Three-phasehttp://en.wikipedia.org/wiki/Coalhttp://en.wikipedia.org/wiki/Conveyorhttp://en.wikipedia.org/wiki/Economiserhttp://en.wikipedia.org/wiki/Steam_turbinehttp://en.wikipedia.org/wiki/Coalhttp://en.wikipedia.org/wiki/Air_preheaterhttp://en.wikipedia.org/wiki/Condensate_pumphttp://en.wikipedia.org/wiki/Pulverizerhttp://en.wikipedia.org/wiki/Electrostatic_precipitatorhttp://en.wikipedia.org/wiki/Surface_condenserhttp://en.wikipedia.org/wiki/Steam_drumhttp://en.wikipedia.org/wiki/Centrifugal_fanhttp://en.wikipedia.org/wiki/Steam_turbinehttp://en.wikipedia.org/wiki/Steam_turbinehttp://en.wikipedia.org/wiki/Bottom_ashhttp://en.wikipedia.org/wiki/Flue_gas_stackhttp://en.wikipedia.org/wiki/Flue_gas_stackhttp://en.wikipedia.org/wiki/Bottom_ashhttp://en.wikipedia.org/wiki/Steam_turbinehttp://en.wikipedia.org/wiki/Steam_turbinehttp://en.wikipedia.org/wiki/Centrifugal_fanhttp://en.wikipedia.org/wiki/Steam_drumhttp://en.wikipedia.org/wiki/Surface_condenserhttp://en.wikipedia.org/wiki/Electrostatic_precipitatorhttp://en.wikipedia.org/wiki/Pulverizerhttp://en.wikipedia.org/wiki/Condensate_pumphttp://en.wikipedia.org/wiki/Air_preheaterhttp://en.wikipedia.org/wiki/Coalhttp://en.wikipedia.org/wiki/Steam_turbinehttp://en.wikipedia.org/wiki/Economiserhttp://en.wikipedia.org/wiki/Conveyorhttp://en.wikipedia.org/wiki/Coalhttp://en.wikipedia.org/wiki/Three-phasehttp://en.wikipedia.org/wiki/Electrical_generatorhttp://en.wikipedia.org/wiki/Combustionhttp://en.wikipedia.org/wiki/Feedwater_heaterhttp://en.wikipedia.org/wiki/Three-phasehttp://en.wikipedia.org/wiki/Transformerhttp://en.wikipedia.org/wiki/Deaeratorhttp://en.wikipedia.org/wiki/Three-phasehttp://en.wikipedia.org/wiki/Electrical_power_transmissionhttp://en.wikipedia.org/wiki/Centrifugal_fanhttp://en.wikipedia.org/wiki/Steam_turbinehttp://en.wikipedia.org/wiki/Superheaterhttp://en.wikipedia.org/wiki/Control_valvehttp://en.wikipedia.org/wiki/Cooling_tower


10/34

DESCRIPTION


11/34

COAL TO STEAM

Coal from the coal wagons is unloaded in the coal handling plant. This coal

is transported up to the raw coal bunkers with the help of belt conveyors. .Coal - How much Coal required for a 100 MW plant per year =

Power Plant Wattage x Coal unit/ Hr x Hr/ Yr = :100 x (Per unit Heat Required/ Coal Heat Value) x (24 x 365) = 100 x (10.765/ 20) x

8760 kg/ Yr = 471.51 x 1000 kg/ Yr = 471.51 mT/ Yr

Coal is transported from the mine to loading place .Wagon Tripler Transported

through conveyors into bunkers . From bunkers the coal is sent into mills i.e bowl

mills where the coal gets pulverized or powdered .The powdered coal is then put intofurnace and burnt .The heat generated is used to heat water, steam, air etc .

BOILER COAL BUNKER

Boiler Coal Coal bunker supplies coal to pulverizing fuel mills. Each bunker can hold

1,000 tonnes of coal, and there may be six to eight bunkers per unit .Power station coal

is not as lumpy as coal used in the home. Typically around half of it is less than 12.5

millimeters across and 95% is less than 50 millimeters . That is the powdered coal

passes through a sieve with so many holes in square inch area. It is better than the face

powder in terms of size

COAL FEEDERS

The variable speed coal feeder feeds coal from the bunkers to the mill . It uses a

conveyor to move coal through a fixed gap at a precisely controlled speed. Varying the

speed controls the amount of coal supplied to the boilers. These are precision bits of

equipment that have to move exact amounts of coal .They can move 40 tonnes of coal in

an hour .

THE MILL

The mill consists of a round metallic table on which coal particles fall. This table is

rotated with the help of a motor. There are three large steel rollers, which are spaced

120 apart. When there is no coal, these rollers do not rotate but when the coal is fed

to the table it packs up between the roller and the table and this forces the roller to

rotate. Coal is crushed by the crushing action between the rollers and the rotating

table .This crashed coal is taken away to the furnace through coal pipes with the help of hot

and cold air mixture from the primary air fans .

PRIMARY AIR FAN


12/34

to blow the coal from the mill to the boiler, called the primary air, is supplied by a

large fan driven by a variable speed motor .

When mixed with a stream of air the powdered coal behaves more like a gas than asolid . Primary air does two jobsheating the coal powder and secondly lifting it into

the furnace through pipelines.

Boiler light-up spark plug provides the initial ignition. Light Diesel oil is then fed to

the burner and it catches fire .This is followed by heavy furnace oil (HFO), once a

stable flame is established the coal/air mix is blown through the burner where it lights

spontaneously The oil are then shut off. Burner position, coal flow and air flow are

controlled to achieve desired output of temperature, pressure and flow.

BOILER

To produce steam each boiler converts energy, in the form of coal, into steam The

boiler is lined with steel tubing in which pure boiler feed water is turned to steam bythe heat created from the burning of coal .Each boiler is as high as 60 mts and weighs

about 40,00,000 kg (4000 T)Inside the boiler there is enough steel tubing to stretch the

500 kilometres and they are joined together by about 20,000 joints Pressure inside the

tubes could be about hundred times that of cars wheel pressure .

Water from the boiler feed pump passes through economiser and reaches the boilerdrum.

ECONOMISER

Flue gases leaving the superheater and reheater still contain useful energy . Water

from the high pressure feed heaters is heated in the economizer from 250C to 290C

before it continues to the steam drum Having given up its last heat in the boiler, the

flue gases move on to the air heater31. Drum After leaving the economizer, the feed

water reaches the drum, which is a cylindrical vessel at the top of the boiler From here

the water flows by natural circulation through downpipes into the boiler Saturated

steam collects here ready to go to the superheater does the important function of -

separating steam from a mixture of steam and water .

CONTROL VALVES

Control valves are valves used within industrial plants and elsewhere to control

operating conditions such as temperature,pressure,flow,and liquid Level by fully

partially opening or closing in response to signals received from controllers that

compares a set point to a process variable whose value is provided by sensorsthat monitor changes in such conditions. The opening or closing of control valves is


13/34

DEARATOR

Dearator is a device for air removal and used to remove dissolved gases (an alternate

would be the use of water treatment chemicals) from boiler feed water to make it non-corrosive. A deaerator typically includes a vertical domed deaeration section as the

deaeration boiler feed water tank.

A Steam generating boiler requires that the circulating steam, condensate, and feedwater should be devoid of dissolved gases, particularly corrosive ones and dissolved or

suspended solids. The gases will give rise to corrosion of the metal. The solids will

deposit on the heating surfaces giving rise to localized heating and tube ruptures due

to overheating. Under some conditions it may give to stress corrosion cracking.

Deaerator level and pressure must be controlled by adjusting control valves- the levelby regulating condensate flow and the pressure by regulating steam flow. If operatedproperly, most deaerator vendors will guarantee that oxygen in the deaerated water

will not exceed 7 ppb by weight (0.005 cm3/L) .

FEED WATER HEATER

A Feed water heater is a power plant component used to pre-heat water delivered to a

steam generating boiler. Preheating the feed water reduces the irreversible 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 introduces back into the steam cycle. In a steam power

(usually modeled as a modified Ranking cycle), feed water heaters allow the feed water

to be brought up to the saturation temperature very gradually. This minimizes the

inevitable irreversibilitys associated with heat transfer to the working fluid (water). Abelt conveyor consists of two pulleys, with a continuous loop of material- the conveyor

Belt that rotates about them. The pulleys are powered, moving the belt and the

material on the belt forward. Conveyor belts are extensively used to transport

industrial and agricultural material, such as grain, coal, ores etc.

PULVERISER

A pulveriser is a device for grinding coal for combustion in a furnace in a fossil fuel

power plant.

BOILER STEAM DRUM

Drums are a regular feature of water tube boilers. It is reservoir of water/steam at the

top end of the water tubes in the water-tube boiler. They store the steam generated inthe water tubes and act as a phase separator for the steam/water mixture. The

diff i d i i b h d ld h l i h l i f h


14/34

hotter-water/and saturatedsteam into steam drum. Made from high-grade steel

(probably stainless) and its working involves temperatures 390C and pressure wellabove 350psi (2.4MPa). The separated steam is drawn out from the top section of the

drum. Saturated steam is drawn off the top of the drum. The steam will re-enter thefurnace in through a super heater, while the saturated water at the bottom of steam

drum flows down to the mud-drum /feed water drum by down comer tubes accessories

include a safety valve, water level indicator and fuse plug. A steam drum is used in thecompany of a mud-drum/feed water drum which is located at a lower level. So that it

acts as a sump for the sludge or sediments which have a tendency to the bottom.

SUPER HEATER

A Super heater is a device in a steam engine that heats the steam generated by theboiler again increasing its thermal energy and decreasing the likelihood that it will

condense inside the engine.

Super heaters increase the efficiency of the steam engine, and were widely adopted.

Steam which has been superheated is logically known as superheated steam; non-

superheated steam is called saturated steam or wet steam; Super heaters were applied

to steam locomotives in quantity from the early 20th century, to most steam vehicles,and so stationary steam engines including power stations.

AIR PREHEATERS

Air preheater is a general term to describe any device designed to heat air before

another process (for example, combustion in a boiler). The purpose of the air preheater

is to recover the heat from the boiler flue gas which increases the thermal efficiency of

the boiler by reducing the useful heat lost in the fuel gas. As a consequence, the flue

gases are also sent to the flue gas stack (or chimney) at a lower temperature allowingsimplified design of the ducting and the flue gas stack. It also allows control over the

temperature of gases leaving the stack.

ESPS

An Electrostatic precipitator (ESP) or electrostatic air cleaner is a particulate device

that removes particles from a flowing gas (such As air) using the force of an induced

electrostatic charge. Electrostatic precipitators are highly efficient filtration devices,

and can easily remove fine particulate matter such as dust and smoke from the air

steam. ESPs continue to be excellent devices for control of many industrial

particulate emissions, including smoke from electricity-generating utilities (coal and

oil fired), salt cake collection from black liquor boilers in pump mills, and catalystcollection from fluidized bed catalytic crackers from several hundred thousand ACFM

in the largest coal fired boiler application The original parallel plate Weighted wire


15/34

electrode designs were developed, today focusing on rigid discharge electrodes to

which many sharpened spikes are attached , maximizing corona production.Transformerrectifier systems apply voltages of 50-100 Kilovolts at relatively high

current densities. Modern controls minimize sparking and prevent arcing, avoidingdamage to the components. Automatic rapping systems and hopper evacuation systems

remove the collected particulate matter while on line allowing ESPs to stay in

operation for years at a time.

FUEL GAS STACK

A Fuel gas stack is a type of chimney, a vertical pipe, channel or similar structure

through which combustion product gases called fuel gases are exhausted to the outside

air. Fuel gases are produced when coal, oil, natural gas, wood or any other largecombustion device. Fuel gas is usually composed of carbon dioxide (CO2) and water

vapor as well as nitrogen and excess oxygen remaining from the intake combustion air.

It also contains a small percentage of pollutants such as particulates matter, carbonmono oxide, nitrogen oxides and sulfur oxides.


16/34

BOILERMAINTENANCE

DEPARTMENT

(BMD)


17/34

BOILER MAINTENANCE DEPARTMENT

The Boiler Maintenance Department (I,II,III) are departments who are

seployed for the proper working and maintenance of the boilers . At BTPSthere are 5 boilers, 3 of 95 MW and 2 of 210 MW each. Each boiler is

considered as one unit. Structure of units 1,2,3 is same and so is of unit 4,5

.

Units 1/2/3 (95 MW each):

1. I.D Fans 2 in no.

2. F.D Fans 2 in no.

3. P.A.Fans 2 in no.

4. Mill Fans 3 in no.

5. Ball mill fans 3 in no.

6. RC feeders 3 in no.

7. Slag Crushers 5 in no.

8. DM Make up

Pump

2 in no.

9. PC Feeders 4 in no.

10. Worm Conveyor 1 in no.

11. Turnikets 4 in no.


18/34

Units 4/5 (210 MW each)

1. I.D Fans 2 in no.

2. F.D Fans 2 in no.

3. P.A Fans 2 in no.

4. Bowl Mills 6 in no.

5. R.C Feeders 6 in no.

6. Clinker Grinder 2 in no.

7. Scrapper 2 in no.

8. Seal Air Fans 2 in no


19/34

Milling System

RC BUNKER

Raw coal is fed directly to these bunkers. These are 3 in no. per boiler. 4 & tons

of coal are fed in 1 hr. the depth of bunkers is 10m.

RC FEEDER

It transports pre crust coal from raw coal bunker to mill. The quantity of raw coal

fed in mill can be controlled by speed control of aviator drive controlling damper

and aviator change.

BALL MILL

The ball mill crushes the raw coal to a certain height and then allows it to fall

down. Due to impact of ball on coal and attraction as per the particles move over

each other as well as over the Armor lines, the coal gets crushed. Large particles

are broken by impact and full grinding is done by attraction. The Drying and

grinding option takes place simultaneously inside the mill.

CLASSIFIER

It is an equipment which serves separation of fine pulverized coal particles medium

from coarse medium. The pulverized coal along with the carrying medium strikes

the impact plate through the lower part. Large particles are then transferred to the

ball mill.

CYCLONE SEPARATOR

It separates the pulverized coal from carrying medium. The mixture of pulverized

coal vapour caters the cyclone separators. .

TURNIKET

It serves to transport pulverized coal from cyclone separators to pulverized coal

bunker or to worm conveyors. There are 4 turnikets per boiler.

WORM CONVEYER

It is equipment used to distribute the pulverized coal from bunker of one system tobunker of other system. It can be operated in both directions. 8. Mills Fans: - It is of


20/34

(a) I D Fans- Located between electrostatic precipitator and chimney. Type-radicalSpeed-1490 rpm 20 Rating-300 KW Voltage-6.6 KV Lubrication-by oil ..

(b) D Fans- Designed to handle secondary air for boiler. 2 in number and provideignition of coal. Type-axial Speed-990 rpm Rating-440 KW Voltage-6.6 KV

(c) Primary Air Fans- Designed for handling the atmospheric air up to 50 degreesCelsius, 2 in numbers,and they transfer the powered coal to burners to firing. Type-

Double suction radial Rating-300 KW Voltage-6.6 KV Lubrication-by oil Type of

operation-continuous

BALL MILL

One of the most advanced designs of coal pulverizes presently manufactured. Motorspecification squirrel cage induction motor Rating-340 KW Voltage-6600KV

Curreen-41.7A Speed-980 rpm Frequency-50 Hz No-load current-15-16 A .


21/34

PLANT AUXILIARY

MAINTENANCE

(PAM)


22/34

PLANT AUXILIARY MAINTENANCE (PAM)

This unit of the plant mainly dealt with the auxiliary or helping parts in the plant eg:

water treatment, ash treatment, pump division etc.This two week of training in this division were divided as follows:

1. Control Structure Pump House (CSPH)

2. Water Treatment Plant (WTP)

3. Ash Pump House (APH)

4. Compressed Air Systems

The details of the above sub units are as follows:

CONTROL STRUCTURE PUMP HOISE (CSPH)

This unit consists of all types of pumps used in plants for purposes like water supply,ash slurry flow etc.

The various types of pumps

Sr.No Types No.1 CRW Pump 3

2 Fire

Fighting

Pump

2

3 Diesel FirePump

1

4 Low

Pressure

Pump

3

5 High

PressurePump

6

6 TWS Pump 3


23/34

CRW pump is raw water pump used in CSPH, through which raw water is sent into

water treatment plant to get demineralised water . Fire Fighting Pump are used topacify fire, which occurs most of the time in Coal Handling Plant. These pumps direct

the screened or strained water into the areas where fire has started. Diesel Fire Pumpis an alternative to Fire fighting pump. It acts as spare. Low Pressure Pump is used to

direct treated water into turbines and cooling lines of units 1, 2, 3, 4, 5. In case LP

pump is not able to send water up to unit 4 or 5, HP pumps are used. High PressurePumps are also used in ash lines, where the ash is directed into slurry pond.

Travelling Water Strainer or TWS pump is used to screen the catchable impurities,

plastics, dirt through screens placed in the inlet of the agra canal channel.

WATER TREATMENT PLANT

The raw water from CSPH is sent to WTP where it is processed and converted into DMwater. This unit has 8 pumps in all, of which 3 pumps are of 210 MW and are used in

running plant, whereas other 5 are 100 MW pumps used in cooling water circulation.

Here, initially raw water is mixed with alum and chlorine, and then passed through

chambers of carbon filter to convert it to clarified water. This water is passed throughresin filter and then mixed with 30 % HCL solution, to form ions. Then it is passed

through cation chamber to separate cations, and similarly anions are removed through

anion chamber. Thus we get carbonated water, this water is passed through the

process of decarbonation, and thus we get DM or Demineralised water.


24/34

Layout

Ash Pump House

In the bottom ash system the ash slag discharged from furnace bottom is collected in

two water impounded scraper troughs installed below bottom ash hoppers. The ash is

continuously transported by means of scrapper chain conveyor, on to the respective

cinker grinders which reduces the lump size to required fineness.

The crushed ash from clinker grinders falls into the ash sluice trench provided below

bottom ash hopper from where ash slurry is further transported to ash slurry sump

aided by the ash sluice channel. If the clinker grinder is not in operation , bottom ash

can be discharged directly into the sluice channel through bifurcating chute bypass thegrinder.


25/34

1. Water Filter Hoppers2. Quencher Cooled Ash Hopper

The various ash disposal systems are:

Fly Ash System

The fly ash collected in these hoppers drop continuously to flushing apparatus where

fly ash gets mixed with flushing water and the resulting slurry drops into the ash sluice

channel. Low pressure water is applied through the nozzle directing tangentially to the

section of pipe to create turbulence and proper mixing of ash with water. For the

maintenance of flushing apparatus plate valve is provided between apparatus andconnecting chute.

Ash Water System

High pressure water required for B.A. hopper quenching nozzles, B.A. hoppers window

spraying, clinker grinder sealing scrapper bars, cleaning nozzles, B.A. hopper seal

through flushing, Economizer hoppers flushing nozzles and sluicing trench jetting

nozzles is tapped from the high pressure water ring main provided in the plant area.

Low pressure water required for bottom ash hopper seal through make up, scrapperconveyor makeup, flushing apparatus jetting nozzles for all.. F.A.hoppers excepting

economiser hoppers, is tapped from low pressure water ring mains provided in the

plant area.

Ash Slurry SystemBottom ash and fly ash slurry of the system is sluiced upto ash slurry pump along the

channel with the aid of high pressure water jets located at suitable intervals along the

channel.

Slurry pump suction line consisting of reducing elbow with drain valve reducer andbutterfly valve and portion of slurry pump delivery line consisting of butterfly valve,

pipe and fittings has also been provided.

Compressed Air SystemsInstrument air is required for operating various dampers , burner tilting devices,

diaphragm valves etc., in the 210 MW units. Station air meets the general requirement

of the power statin such as light oil atomising air, for cleaning filters and for various

maintenance works. The control air compressors have been housed separately withseparate receivers and supply headers and their tappings.


26/34

Control Air System

These have been installed for supplying moisture free dry air required for instrument

used. The output from the compressor is fed to air receivers via non return valves.From the receiver air is passed through the dryers to the main instrument air line

which runs alongwith the boiler house and turbine house of 210 MW unit.

There is one interconnection between service air and instrument air headers just at the

inlet of drying units. This connection has been provided as an emergency provision to

meet the requirement of instrument air in case of non-availability of instrument air

compressor. The line connecting the service air header with instrument air header is

provided with two isolating valves , one oil separator, one activated carbon filter, one

non return valve and one regulating valve. Oil and dust free air is supplied to the

instrument air header which is then passed through air drier units. Instrument aircompressor are of double acting horizontal cross head type of two opposed cylinder.

The compressors are driven by electric motor through V belts. Gear wheel type

lubricating oil pump is provided to feed the main bearing. Connecting rod bearing and

cross heads of one side ie. to the opposite side of crank shaft rotation piston. Thecompressor is equipped with water cooled inter cooler or header, pressure regulator to

load and unload the compressor and safety valves for first and second stages. The

suction air filter is at the middle of the cylinder so that air can enter at both ends of the

piston. After compression the air passes through the delivery valves to the intercooler

where the air is cooled and enters the HP cylinder. The entrapped air in HP side iscompressed in a similar manner as in LP cylinder to the required pressure and enters

the header connected to the HP cylinders through the delivery valves and then finally

to the air receiver.

Air Drying Unit

Air contains moisture which tends to condense, and cause trouble in operation of

various devices by compressed air. Therefore drying of air is accepted widely in case

of instrument air. Air drying unit consists of dual absorption towers with embedded

heaters for reactivation. The absorption towers are adequetly filled with speciallyselected silica gel and activated alumina .While one tower is drying the air , the other

tower is under reactivation. Thus the unit maintains continuous supply of dry air for

plant requirement. Thus the system is completely automatic.


27/34

TURBINE MAINTENANCE

DIVISION

(TMD)


28/34

TURBINE MAINTENANCE DIVISION (TMD)

A turbine, being a form of engine, requires in order to function a suitable working

fluid, a source of high grade energy and a sink for low grade energy. When the fluidflows through the turbine, part of the energy content is continuously extracted and

converted into useful mechanical work.

The data about the turbine of 210 MW is shown below :

MAIN TURBINE DATA

Rated output of Turbine 210 MW

Rated speed of turbine 3000 rpmRated pressure of steam

before emergency

130 kg/cm^2

Stop valve rated live steam

temperature

535 degree Celsius

Rated steam temperature afterreheat at inlet to receptor

valve

535 degree Celsius

Steam flow at valve wide opencondition 670 tons/hour

Rated quantity of circulating

water through condenser

27000 cm/hour

1. For cooling water

temperature (degree Celsius)

24,27,30,33

1.Reheated steam pressure at

inlet of interceptor valve in

kg/cm^2 ABS

23,99,24,21,24,49,24.82

2.Steam flow required for 210

MW in ton/hour

68,645,652,662

3.Rated pressure at exhaust of

LP turbine in mm of Hg

19.9,55.5,65.4,67.7

Turbine Components

The Main Turbine

The 210 MW turbine installed in our power stations is predominantly of condensing-

tandom compound three cylinder horizontal disc and diaphragm reheat type with


29/34

The various main components of the steam turbine are as follows :

Turbine casings

I. High Pressure Casing

II. Intermediate Pressure Casing

III. Low Pressure Casing

Rotors

I. High Pressure Rotor

II. Intermediate Pressure Rotor

III. Low Pressure Rotor

Blades

Blades fitted in stationary part are called guide blades or nozzles and those fitted in the

rotor are called moving or working blades. The following are three main types ofblades.

Ar rangement Of Turbine Auxi li aries

The turbine cycle can be viewed in the form of different systems as given in following

paragraphs

I. Condenser- 2 per 210 MW unit at the exhaust of LP turbine


30/34

II. Ejectors- One starting and two main ejectors connected to the condenser locatednear the turbine

II. C.W. pumpsNormally two per unit of 50 % capacity

I. Condensate Pumps- 3 per unit of 50% capacity each located near the condenser hotwell.

II. LP heaters- Normally 4 in number with no.1 located at ther upper part of thecondenser and nos 2,3,4 around 4m level

III. Deaerator- One per unit located around 18 M level in CD bay

Feed Water System

I. Boiler Feed Pump- 3 per unit of 50% capacity each located in the 0 meter level in

TG bay

II. High Pressure Heaters- Normally 3 in number and are situated in the TG bay

Drip Pumps

Generally two in number of 100% capacity each situated beneath the LP heaters

Turbine Lubricant Oil system

This consists of Main Oil Pump(MOP), Starting Oil Pump(SOP), AC standby oil pumps

and emergency DC oil pump and Jacking Oil Pump (JOP) (one each per unit)

Auxiliary Steam System

The main 16 ata header runs parallel to BC bay at the level ofaround 18M.

The arrangement of turbine auxiliaries is shown in the following figure:


31/34


32/34


33/34

INFERENCE

In my four week training, I was assigned the work of three units, which wereBMD, PAM

and TMD. These 3 units are explained above in chapter 3, of this report.Boiler and turbine are the most important part of the power plant, without

which the power plant cannot run. This plant produces 705 MW of electricity,with the help of its 5 units. 3 units of 95 MW each and 2 units of 210 MW

each. The 95 MW units were the first ones to be established followed by the210 MW units in the later years. As for the unit PAM, it is equally important.It takes care of all the auxiliary processes going on in the plant. It provides

water to all the parts of the plant with the help of pumps present in CSPH.

Also it produces DM water from raw water by passing it through water

treatment plant. The ash or the waste produced on burning is taken care of, byAsh handling plant. The compressed air required in any part of the plant isprovided by the unit comprising of the compressor, also known as compressorhouse. The fuel used was coal which was pulverized with the help of bowl andball mills. These pulverized coal was the fuel burnt in the furnace to produce

heat, which then heated the water to superheated steam.

30


34/34

REFERENCES

1.Training Staffat BTPS

badarpur

2.Manualsprovided by

NTPC .

3.Senior studentsand Teachers .

Report @Ntpc

Documents

Transcript of Report @Ntpc