Summer Trainig Report Part1

8/4/2019 Summer Trainig Report Part1

1/18

SUMMER TRAINING REPORT21stJune to 6thAugust

Badarpur Thermal Power Station

Submitted By:-DHRUV

AHUJAB.Tech, 3rd year


2/18

K.I.I.T

This is to certify that DHRUV AHUJA(Roll no. 34039), student

of 2008-2012 Batch ofElectrical & Electronics Branch in 3rd

Year ofKIIT, Bhondsi has successfully completed his industrial

training atBadarpur Thermal Power Station- NTPC, New Delhi

for four weeks from 21st June to 6th August 2011. He has

completed the whole training as per the training report submittedby him.

Training In-charge

Badarpur Thermal Power Station

NTPC


3/18

Badarpur, New Delhi.

Acknowledgement

With profound respect and gratitude, I take the opportunity to convey my thanks to

complete the training here. I express gratitude to the Program Manager and other

faculty members of Electrical & Electronics Engineering Department of KIIT for

providing this opportunity to undergo industrial training at National Thermal

Power Corporation, Badarpur, New Delhi.

I am extremely grateful toMr. G.D.Sharma, Superintendent of Im-Plant Trainingat BTPS-NTPC, Badarpur for his guidance during whole training.

I am extremely grateful to all the technical staff of BTPS-NTPC for their co-

operation and guidance that helped me a lot during the course of training. I have

learnt a lot working under them and I will always be indebted of them for this

value addition in me.

Finally, I am indebted to all whosoever have contributed in this report work and

friendly stay at Badarpur Thermal Power Station, Badarpur, New Delhi.

ABOUT THE COMPANY


4/18

CORPORATE VISION

A world class integrated power major, powering India's growth with increasingglobal presence.

CORE VALUES:

BCOMIT

B- Business ethics

C- Customer focus

O- Organizational & professional pride

M- Mutual respect & trust

I- Innovation & speed

T- Total quality for excellence

NTPC Limited is the largest thermal power generating company of India, Public

Sector Company. It was incorporated in the year 1975 to accelerate power

development in the country as a wholly owned company of the Government of

India. At present, Government of India holds 89.5% of the total equity shares of

the company and the balance 10.5% is held by FIIs, Domestic Banks, Public and

others. Within a span of 31 years, NTPC has emerged as a truly national power

company, with power generating facilities in all the major regions of the country.

NTPC's core business is engineering, construction and operation of power

generating plants and providing consultancy to power utilities in India and abroad.


5/18

The total installed capacity of the company is 31134 MW (including JVs) with 15

coal based and 7 gas based stations, located across the country. In addition under

JVs, 3 stations are coal based & another station uses naphtha/LNG as fuel. By

2017, the power generation portfolio is expected to have a diversified fuel mix

with coal based capacity of around 53000 MW, 10000 MW through gas, 9000 MWthrough Hydro generation, about 2000 MW from nuclear sources and around 1000

MW from Renewable Energy Sources (RES). NTPC has adopted a multi-pronged

growth strategy which includes capacity addition through green field projects,

expansion of existing stations, joint ventures, subsidiaries and takeover of stations.

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

company has 18.79% of the total national capacity it contributes 28.60% of total

power generation due to its focus on high efficiency. NTPCs share at 31 Mar 2001

of the total installed capacity of the country was 24.51% and it generated 29.68%

of the power of the country in 2008-09. Every fourth home in India is lit by NTPC.

170.88BU of electricity was produced by its stations in the financial year 2005-

2006. The Net Profit after Tax on March 31, 2006 was INR 58,202 million. Net

Profit after Tax for the quarter ended June 30, 2006 was INR 15528 million, which

is 18.65% more than for the same quarter in the previous financial year. 2005).

Pursuant to a special resolution passed by the Shareholders at the Companys

Annual General Meeting on September 23, 2005 and the approval of the Central

Government under section 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 October 28, 2005. The primary reason for this is

the company's foray into hydro and nuclear based power generation along with

backward integration by coal mining.

A graphical overview


6/18

STRATEGIES


7/18


8/18

OPERATION

Introduction

Steam Generator or Boiler

Steam Turbine Electric Generator

Introduction


9/18

The operating performance of NTPC has been considerably above the national

average. The availability factor for coal stations has increased from 85.03 % in

1997-98 to 90.09 % in 2006-07, which compares favourably with international

standards. The PLF has increased from 75.2% in 1997-98 to 89.4% during the year

2006-07 which is the highest since the inception of NTPC.

Operation Room of Power Plant

In Badarpur Thermal Power Station, steam is produced and used to spin a turbine

that operates a generator. Water is heated, turns into steam and spins a steam

turbine which drives an electrical generator. After it passes through the turbine, the

steam is condensed in a condenser; this is known as a Rankine cycle. Shown here

is a diagram of a conventional thermal power plant, which uses coal, oil, or natural

gas as fuel to boil water to produce the steam. The electricity generated at the plant

is sent to consumers through high-voltage power lines.

The Badarpur Thermal Power Plant has Steam Turbine-Driven Generators which

has a collective capacity of 705MW.The fuel being used is Coal which is supplied from the Jharia Coal Field in

Jharkhand.

Water supply is given from the Agra Canal.


10/18

Table: Capacity of Badarpur Thermal Power Station, (BTPS) New Delhi

There are basically three main units of a thermal power plant:

1. Steam Generator or Boiler

2. Steam Turbine

3. Electric Generator

We have discussed about the processes of electrical generation further. A complete

detailed description of two (except 2) units is given further.

Coal is conveyed (14) from an external stack and ground to a very fine powder by

large metal spheres in the pulverised fuel mill (16). There it is mixed withpreheated air (24) driven by the forced draught fan (20). The hot air-fuel mixture is

forced at high pressure into the boiler where it rapidly ignites. Water of a high

purity flows vertically up the tube-lined walls of the boiler, where it turns into

steam, and is passed to the boiler drum, where steam is separated from any

remaining water. The steam passes through a manifold in the roof of the drum into

the pendant super heater (19) where its temperature and pressure increase rapidly

to around 200 bar and 540C,


11/18


12/18

sufficient to make the tube walls glow a dull red. The steam is piped to the high

pressure turbine (11), the first of a three-stage turbine process. A steam governor

valve (10) allows for both manual control of the turbine and automatic set-point

following. The steam is exhausted from the high pressure turbine, and reduced in

both pressure and temperature, is returned to the boiler reheater (21). The reheated

steam is then passed to the intermediate pressure turbine (9), and from there passed

directly to the low pressure turbine set (6). The exiting steam, now a little above its

boiling point, is brought into thermal contact with cold water (pumped in from the

Cooling tower) in the condenser (8), where it condenses rapidly back into water,

creating near vacuum-like conditions inside the condensor chest. The condensed

water is then passed by a feed pump (7) through a deaerator (12), and pre-warmed,

first in a feed heater (13) powered by steam drawn from the high pressure set, and

then in the economiser (23), before being returned

to the boiler drum. The cooling water from the condensor is sprayed inside a

cooling tower (1), creating a highly visible plume of water vapour, before beingpumped back to the condensor (8) in cooling water cycle. The three turbine sets are

sometimes coupled on the same shaft as the three-phase electrical generator (5)

which generates an intermediate level voltage (typically 20-25 kV). This is stepped

up by the unit transformer (4) to a voltage more suitable for transmission (typically

250-500 kV) and is sent out onto the three-phase transmission system (3). Exhaust

gas from the boiler is drawn by the induced draft fan (26) through an electrostatic

precipitator (25) and is then vented through the chimney stack (27).

Steam Generator/BoilerThe boiler is a rectangular furnace about 50 ft (15 m) on a side and 130 ft (40 m)

tall. Its walls are made of a web of high pressure steel tubes about 2.3 inches (60

mm) in diameter. Pulverized coal is air-blown into the furnace from fuel nozzles at

the four corners and it rapidly burns, forming a large fireball at the center. The

thermal radiation of the fireball heats the water

that circulates through the boiler tubes near the boiler perimeter. The water

circulation rate in the boiler is three to four times the throughput and is typically

driven by pumps. As the water in the boiler circulates it absorbs heat and changesinto steam at 700 F (370 C) and 3,200 psi (22.1MPa). It is separated from the

water inside a drum at the top of the furnace. The saturated steam is introduced

into superheat pendant tubes that hang in the hottest part of the combustion gases

as they exit the furnace. Here the steam is superheated to 1,000 F (540 C) to

prepare it for the turbine. The steam generating boiler has to produce steam at the

high purity, pressure and temperature required for the steam turbine that drives the


13/18

electrical generator. The generator includes the economizer, the steam drum, the

chemical dosing equipment, and the furnace with its steam generating tubes and

the superheater coils. Necessary safety valves are located at suitable points to avoid

excessive boiler pressure. The air and flue gas path equipment include: forced draft

(FD) fan, air preheater (APH), boiler furnace, induced draft (ID) fan, fly ash

collectors (electrostatic precipitator or baghouse) and the flue gas stack.

For units over about 210 MW capacity, redundancy of key components is provided

by installing duplicates of the FD fan, APH, fly ash collectors and ID fan with

isolating dampers. On some units of about 60 MW, two boilers per unit may

instead be provided.

Schematic diagram of a coal-fired power plant steam generator

Boiler Furnace and Steam Drum

Once water inside the boiler or steam generator, the process of adding the latent

heat of vaporization or enthalpy is underway. The boiler transfers energy to thewater by the chemical reaction of burning some type of fuel.

The water enters the boiler through a section in the convection pass called the

economizer. From the economizer it passes to the steam drum. Once the water

enters the steam drum it goes down the down comers to the lower inlet water wall

headers. From the inlet headers the water rises through the water walls and is

eventually turned into steam due to the heat being generated by


14/18

the burners located on the front and rear water walls (typically). As the water is

turned into steam/vapour in the water walls, the steam/vapour once again enters the

steam drum.

External View of an Industrial Boiler at BTPS, New Delhi

The steam/vapour is passed through a series of steam and water separators and then

dryers inside the steam drum. The steam separators and dryers remove the water

droplets from the steam and the cycle through the water walls is repeated. This

process is known as natural circulation. The boiler furnace auxiliary equipment

includes coal feed nozzles and igniter guns, soot blowers, water lancing and

observation ports (in the furnace walls) for observation of the furnace interior.

Furnace explosions due to any accumulation of combustible gases after a tripout

are avoided by flushing out such gases from the combustion zone before igniting

the coal. The steam drum (as well as the superheater coils and headers) have air

vents and drains needed for initial start-up. The steam drum has an internal device

that removes moisture from the wet steam entering the drum from the steam


15/18

generating tubes. The dry steam then flows into the superheater coils. Geothermal

plants need no boiler since they use naturally occurring steam sources. Heat

exchangers may be used where the geothermal steam is very corrosive or contains

excessive suspended solids. Nuclear plants also boil water to raise steam, either

directly passing the working steam through the reactor or else using an

intermediate heat exchanger.

Fuel Preparation System

In coal-fired power stations, the raw feed coal from the coal storage area is first

crushed into small pieces and then conveyed to the coal feed hoppers at the boilers.

The coal is next pulverized into a very fine powder. The pulverisers may be ball

mills, rotating drum grinders, or other types of grinders. Some power stations burn

fuel oil rather than coal. The oil must kept warm (above its pour point) in the fueloil storage tanks to prevent the oil from congealing and becoming unpumpable.

The oil is usually heated to about 100C before being pumped through the furnace

fuel oil spray nozzles.

Boiler Side of the Badarpur Thermal Power Station, New Delhi


16/18

Boilers in some power stations use processed natural gas as their main fuel. Other

power stations may use processed natural gas as auxiliary fuel in the event that

their main fuel supply (coal or oil) is interrupted. In such cases, separate gas

burners are provided on the boiler furnaces.

Fuel Firing System and Igniter System

From the pulverized coal bin, coal is blown by hot air through the furnace coal

burners at an angle which imparts a swirling motion to the powdered coal to

enhance mixing of the coal powder with the incoming preheated combustion air

and thus to enhance the combustion. To provide sufficient combustion temperature

in the furnace before igniting the powdered coal, the furnace temperature is raised

by first burning some light fuel oil or processed natural gas (by using auxiliary

burners and igniters provide for that purpose).

Air Path

External fans are provided to give sufficient air for combustion. The forced draft

fan takes air from the atmosphere and, first warming it in the air preheater for

better combustion, injects it via the air nozzles on the furnace wall. The induced

draft fan assists the FD fan by drawing out combustible gases from the furnace,

maintaining a slightly negative pressure in the furnace to avoid backfiring through

any opening. At the furnace outlet and before the furnace gases are handled by theID fan, fine dust carried by the outlet gases is removed to avoid atmospheric

pollution. This is an environmental limitation prescribed by law, and additionally

minimizes erosion of the ID fan.

Auxiliary Systems

Fly Ash Collection

Fly ash is captured and removed from the flue gas by electrostatic precipitators or

fabric bag filters (or sometimes both) located at the outlet of the furnace and before

the induced draft fan. The fly ash is periodically removed from the collection

hoppers below the precipitators or bag filters. Generally, the fly ash is

pneumatically transported to storage silos for subsequent transport by trucks or

railroad cars.


17/18

Bottom Ash Collection and Disposal

At the bottom of every boiler, a hopper has been provided for collection of the

bottom ash from the bottom of the furnace. This hopper is always filled with water

to quench the ash and clinkers falling down from the furnace. Some arrangement isincluded to crush the clinkers and for conveying the crushed clinkers and bottom

ash to a storage site.

Boiler Make-up Water Treatment Plant and Storage

Since there is continuous withdrawal of steam and continuous return of condensate

to the boiler, losses due to blow-down and leakages have to be made up for so as to

maintain the desired water level in the boiler steam drum. For this, continuous

make-up water is added to the boiler water system. The impurities in the raw water

input to the plant generally consist of calcium and magnesium salts which imparthardness to the water. Hardness in the make-up water to the boiler will form

deposits on the tube water surfaces which will lead to overheating and failure of

the tubes. Thus, the salts have to be removed from the water and that is done by a

Water Demineralising Treatment Plant (DM).

Ash Handling System at Badarpur Thermal Power Station, New Delhi


18/18

A DM plant generally consists of cation, anion and mixed bed exchangers. The

final water from this process consists essentially of hydrogen ions and hydroxide

ions which is the chemical composition of pure water. The DM water, being very

pure, becomes highly corrosive once it absorbs oxygen from the atmosphere

because of its very high affinity for oxygen absorption. The capacity of the DM

plant is dictated by the type and quantity of salts in the raw water input. However,

some storage is essential as the DM plant may be down for maintenance. For this

purpose, a storage tank is installed from which DM water is continuously

withdrawn for boiler make-up. The storage tank for DM water is made from

materials not affected by corrosive water, such as PVC. The piping and valves are

generally of stainless steel. Sometimes, a steam blanketing arrangement or

stainless steel doughnut float is provided on top of the water in the tank to avoid

contact with atmospheric air. DM water make-up is generally added at the steam

space of the surface condenser (i.e., the vacuum side). This arrangement not only

sprays the water but also DM water gets deaerated, with the dissolved gases beingremoved by the ejector of the condenser itself.

Documents

Summer Trainig Report Part1