Summer Traning Report 6

8/3/2019 Summer Traning Report 6

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SUMMER TRANING REPORT

NATIONAL THERMAL POWER COOPERATION

BADARPUR THERMAL POWER STATION

NEW DELHI

Submitted by:

Nikhil kainth

B.tech Final year

90680573136

Electrical Engineering

Duration-


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CONTENT

1. INTRODUCTION TO THE COMPANY

2. OPERATION OF POWER PLANT

3. VARIOUS CYCLE AT POWER STATION

4. CONTROL & INSTRUMENTATION

5. IT DEPARTMENT

6. REFERENCE


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Introduction to the company

About The Company

Vision

Strategies

Environmental Policy

Evolution


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About The CompanyNTPC, the largest power Company in India, was setup in 1975 to accelerate powerdevelopment in the country. It is among the worlds largest and most efficient powergeneration companies. In Forbes list of Worlds 2000 Largest Companies for the year

2007, NTPC occupies 411th place.

A View Of Badarpur Thermal Power Station, New-Delhi

NTPC has installed capacity of 29,394 MW. It has 15 coal based power stations (23,395 MW), 7gasbased power stations (3,955 MW) and 4 power stations in Joint Ventures (1,794 MW).Thecompany has power generating facilities in all major regions of the country. It plans to be a

75,000MW company by 2017.

Types of power station Number Capacity (MW)

Coal Based Power Station 15 23,395

Gas Based Power Station 7 3,955

Joint Venture 4 1,794

Total Capacity29,394 MW

NTPC has gone beyond the thermal power generation. It has diversified into hydro power, coalmining,

power equipment manufacturing, oil & gas exploration, power trading & distribution. NTPC is now in theentire power value chain and is poised to become an Integrated Power Major. NTPC's share on 31 Mar

2008 in the total installed capacity of the country was 19.1% and it contributed 28.50% of the total powergeneration of the country during 2007-08. NTPC has set new benchmarks for the power industry both in

the area of power plant construction and operations. With its experience and expertise in the power

sector, NTPC is extending consultancy services to various organizations in the power business. It provides

consultancy in the area of power plant constructions and power generation to companies in India and

abroad. In November 2004, NTPC came out with its Initial Public Offering (IPO) consisting of 5.25% as

fresh issue and 5.25% as offer for sale by Government of India. NTPC thus became a listed company with

Government holding 89.5% of the equity share capital and rest held by Institutional Investors and Public.

The issue was a resounding success. NTPC is among the largest five companies in India in terms of marketcapitalization.


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VISIONCorporate vision: -A world class integrated power major, powering India's growth withincreasing global presence.

Mission:-Develop and provide reliable power related products and services at competitiveprices, integrating multiple energy resources with innovative & Eco-friendly technologies andcontribution to the society.

Core Values - BCOMIT

Business ethics

Customer Focus

Organizational & Professional Pride

Mutual Respect & Trust

Innovation & Speed

Total Quality for Excellence

A View Of Well Flourished Plant


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STRATEGIES

SustainableDevolpment

NuturingHuman Maintain sector

Resource Leadership

STRATEGIES

FurtherEnchance

Technology FuelInitiative Security

Exploit NewBusiness

Oportuinity

Technological Initiatives

Introduction of steam generators (boilers) of the size of 800 MW.

Integrated Gasification Combined Cycle (IGCC) Technology.

Launch of Energy Technology Centre -A new initiative for development of technologies with focuson fundamental R&D.

The company sets aside up to 0.5% of the profits for R&D.

Roadmap developed for adopting Clean Development

Mechanism to help get / earn Certified Emission Reduction

Corporate Social Responsibility

As a responsible corporate citizen NTPC has taken up number of CSR initiatives.

NTPC Foundation formed to address Social issues at national level.

NTPC has framed Corporate Social Responsibility Guidelines committing up to 0.5% of net profit

annually for Community Welfare Measures on perennial basis.

The welfare of project affected persons and the local population around NTPC projects are takencare of through well drawn Rehabilitation and Resettlement policies.

The company has also taken up distributed generation for remote rural areas.


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ENVIRONMENTAL POLICY

NTPC is committed to the environment, generating power at minimal environmental cost andpreserving the ecology in the vicinity of the plants. NTPC has undertaken massive a forestationin the vicinity of its plants. Plantations have increased forest area and reduced barren land. The

massive a forestation by NTPC in and around its Ramagundam Power station (2600 MW) havecontributed reducing the temperature in the areas by about 3c. NTPC has also taken proactivesteps for ash utilization. In 1991, it set up Ash Utilization Division

ACentre for Power Efficiency and Environment Protection- CENPEE"has been established in NTPC with the assistance of United States Agency for InternationalDevelopment- USAID. CENPEEPis efficiency oriented, eco-friendly and eco-nurturing initiative -

a symbol of NTPC's concern towards environmental protection and continued commitmentto sustainable power development in India.

As a responsible corporate citizen, NTPC is making constant efforts to improve the socio-economic status of the people affected by its projects. Through its Rehabilitation andResettlement programmes, the company endeavours to improve the overall socio economic statusProject Affected Persons.

NTPC was among the first Public Sector Enterprises to enter into a Memorandumof Understanding-MOU with the Government in 1987-88. NTPC has been placed underthe 'Excellent category' (the best category) every year since the MOU system becameoperative.

Harmony between man and environment is the essence of healthy life and growth. Therefore,maintenance of ecological balance and a pristine environment has been of utmost importance toNTPC. It has been taking various measures discussed below for mitigation of environmentpollution due to power generation.

NTPC is the second largest owner of trees in the country after the Forest

Department.

Environment Policy & Environment Management SystemDriven by its commitment for sustainable growth of power, NTPC has evolved a well definedenvironment management policy and sound environment practices for minimizing environmental

impact arising out of setting up of power plants and preserving the natural ecology.

NTPC Environment PolicyAs early as in November 1995, NTPC brought out a comprehensive document entitled "NTPCEnvironment Policy and Environment Management System". Amongst the guiding principlesadopted in the document are company's proactive approach to environment, optimum utilizationof equipment, adoption of latest technologies and continual environment improvement. The policyalso envisages efficient utilization of resources, thereby minimizing waste, maximizing ashutilization and providing green belt all around the plant for maintaining ecological balance


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Environment Management, Occupational Health and Safety Systems:

NTPC has actively gone for adoption of best international practices on environment, occupationalhealth and safety areas. The organization has pursued the Environmental Management System

(EMS) ISO 14001 and the Occupational Health and Safety Assessment System OHSAS 18001at its different establishments. As a result of pursuing these practices, all NTPC power stationshave been certified for ISO 14001 & OHSAS 18001 by reputed national and internationalCertifying Agencies.

Pollution Control systems:

While deciding the appropriate technology for its projects, NTPC integrates many environmentalprovisions into the plant design. In order to ensure that NTPC comply with all the stipulatedenvironment norms, various state-of-the-art pollution control systems / devices as discussedbelow have been installed to control air and water pollution.

Electrostatic Precipitators:

The ash left behind after combustion of coal is arrested in high efficiency ElectrostaticPrecipitators (ESPs) and particulate emission is controlled well within the stipulated norms. The

ash collected in the ESPs is disposed to Ash Ponds in slurry form.

Flue Gas Stacks:

Tall Flue Gas Stacks have been provided for wide dispersion of the gaseous emissions (SOX,NOXetc) into the atmosphere.

Low-NOX Burners:

In gas based NTPC power stations, NOx emissions are controlled by provision of Low-NOxBurners(dry or wet type) and in coal fired stations, by adopting best combustion practices.

Neutralisation Pits:

Neutralisation pits have been provided in the Water Treatment Plant (WTP) for pH correctionof the effluents before discharge into Effluent Treatment Plant (ETP) for further treatmentand use.

Coal Settling Pits / Oil Settling Pits:

In these Pits, coal dust and oil are removed from the effluents emanating from the CoalHandling Plant (CHP), coal yard and Fuel Oil Handling areas before discharge into ETP.

DE & DS Systems:

Dust Extraction (DE) and Dust Suppression (DS) systems have been installed in all coal firedpower stations in NTPC to contain and extract the fugitive dust released in the Coal HandlingPlant (CHP).


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Cooling Towers:

Cooling Towers have been provided for cooling the hot Condenser cooling water in closed cycleCondenser Cooling Water (CCW) Systems. This helps in reduction in thermal pollution andconservation of fresh water.

Ash Dykes & Ash Disposal systems:

Ash ponds have been provided at all coal based stations except Dadri where Dry Ash DisposalSystem has been provided. Ash Ponds have been divided into lagoons and provided withgarlanding arrangements for changeover of the ash slurry feed points for even filling of the

pond and for effective settlement of the ash particles.

Ash in slurry form is discharged into the lagoons where ash particles get settled from theslurry and clear effluent water is discharged from the ash pond. The discharged effluentsconform to standards specified by CPCB and the same is regularly monitored.

At its Dadri Power Station, NTPC has set up a unique system for dry ash collection anddisposalfacility with Ash Mound formation. This has been envisaged for the first time in Asia

which has resulted in progressive development of green belt besides far less requirement ofland and less water requirement as compared to the wet ash disposal system.

Ash Water Recycling System:

Further, in a number of NTPC stations, as a proactive measure, Ash Water Recycling System

(AWRS)has been provided. In the AWRS, the effluent from ash pond is circulated back to thestation for further ash sluicing to the ash pond. This helps in savings of fresh waterrequirements for transportation of ash from the plant.

The ash water recycling system has already been installed and is in operation atRamagundam,Simhadri, Rihand, Talcher Kaniha, Talcher Thermal, Kahalgaon, Korba andVindhyachal. The scheme has helped stations to save huge quantity of fresh water required asmake-up water for disposal of ash.

Dry Ash Extraction System (DAES):

Dry ash has much higher utilization potential in ash-based products (such as bricks,aeratedautoclaved concrete blocks, concrete, Portland pozzolana cement, etc.). DAES has beeninstalled at Unchahar, Dadri, Simhadri, Ramagundam, Singrauli, Kahalgaon, Farakka, TalcherThermal, Korba,Vindhyachal, Talcher Kaniha and BTPS.

Liquid Waste Treatment Plants & Management System:

The objective of industrial liquid effluent treatment plant (ETP) is to discharge lesser andcleaner effluent from the power plants to meet environmental regulations. After primarytreatment at the source of their generation, the effluents are sent to the ETP for furthertreatment. The composite liquid effluent treatment plant has been designed to treat all liquideffluents which originate within the power station e.g. Water Treatment Plant (WTP),Condensate Polishing Unit (CPU) effluent,


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Coal Handling Plant (CHP) effluent, floor washings, service water drains etc. The scheme involvescollection of various effluents and their appropriate treatment centrally and re-circulation ofthe treated effluent for various plant uses.

NTPC has implemented such systems in a number of its power stations such asRamagundam,Simhadri, Kayamkulam, Singrauli, Rihand, Vindhyachal, Korba, Jhanor Gandhar,

Faridabad, Farakka,Kahalgaon and Talcher Kaniha. These plants have helped to control qualityand quantity of the effluents discharged from the stations.

Sewage Treatment Plants & Facilities:

Sewage Treatment Plants (STPs) sewage treatment facilities have been provided at all NTPC

stations to take care of Sewage Effluent from Plant and township areas. In a number of NTPCprojects modern type STPs with Clarifloculators, Mechanical Agitators, sludge drying beds, GasCollection Chambers etc have been provided to improve the effluent quality. The effluent

quality is monitored regularly and treated effluent conforming to the prescribed limit isdischarged from the station. At several stations, treated effluents of STPs are being used forhorticulture purpose.

Environmental Institutional Set-up:

Realizing the importance of protection of the environment with speedy development of thepower sector, the company has constituted different groups at project, regional and CorporateCentre level to carry out specific environment related functions. The Environment ManagementGroup, Ash Utilisation Group and Centre for Power Efficiency & Environment Protection(CENPEEP)function from the Corporate Centre and initiate measures to mitigate the impact of

power project implementation on the environment and preserve ecology in the vicinity of theprojects. Environment Management and Ash Utilisation Groups established at each station, lookafter various environmental issues of the individual station.

Environment Reviews:

To maintain constant vigil on environmental compliance, Environmental Reviews are carried outatall operating stations and remedial measures have been taken wherever necessary. As afeedbackand follow-up of these Environmental Reviews, a number of retrofit and up-gradationmeasures have been undertaken at different stations.

Such periodic Environmental Reviews and extensive monitoring of the facilities carried out at allstations have helped in compliance with the environmental norms and timely renewal of the Airand Water Consents.

Waste Management

Various types of wastes such as Municipal or domestic wastes, hazardous wastes, Bio-Medicalwastes get generated in power plant areas, plant hospital and the townships of projects. Thewastes generated are a number of solid and hazardous wastes like used oils & waste oils, grease,


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lead acid batteries, other lead bearing wastes (such as markets etc.), oil & clarifier sludge,

used resin, used photo-chemicals, asbestos packing, e-waste, metal scrap, C&I wastes, electrical

scrap, empty cylinders (refillable), paper, rubber products, canteen (bio-degradable) wastes,

building material wastes, silica gel, glass wool, fused lamps & tubes, fire resistant fluids etc.

These wastes fall either under hazardous wastes category or non-hazardous wastes category as

per classification given in Government of Indias notification on Hazardous Wastes (Management

and Handling)Rules 1989 (as amended on 06.01.2000 & 20.05.2003). Handling and management of

these wastes in NTPC stations have been discussed below


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OPERATION OF POWER PLANT

INTRODUCTION

BASIC PRINCIPLE

ELECTRICITY FROM COAL

OPERATION OF BOILER

OPERATION OF TURBINE


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INTRODUCTION

BADARPUR THERMAL POWER STATION was established on 1973 and it was the part ofCentral Government. On 01/04/1978 is was given as No Loss No Profit Plant of NTPC.

Since then 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 % in2006-07,which compares favourably with international standards. The PLF has increased from75.2% in1997-98 to 89.4% during the year 2006-07 which is the highest since the inception ofNTPC

Capacity of BADARPUR THERMAL POWER STATION

Sr.no capacity (mw) Number Total Capacity (MW)

1 210 2 420

2 95 3 285

Overall Capacity- 705 MW

BASIC PRINCIPLE

As per faradays law Whenever the amount of magnetic flux linked with a circuit changes, anEMF is produced in the circuit. Generator works on the principle of producing electricity. To

change the flux in the generator turbine is moved in a great speed with steam.

To produce steam, water is heated in the boilers by burning the coal. In a Badarpur ThermalPowerStation, steam is produced and used to spin a turbine that operates a generator. Wateris 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 aRankine cycle. Shown here is a diagram of a conventional thermal power plant, which uses coal,oil, or natural gases fuel to boil water to produce the steam. The electricity generated at theplant is sent to consumers through high-voltage power lines. The Badarpur Thermal Power Planthas Steam Turbine-Driven Generators which has a collective capacity of 705MW. The fuelbeing used is Coal which is supplied from the Jharia Coal Field in Jharkhand. Water supply is

given from the Agra Canal.


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Electricity from Coal

There are basically three main units of a thermal power plant:1. feed water pump

2. Steam Generator or Boiler3. Steam Turbine4. Electric Generator (Output)


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Functioning of Thermal Power Plant

Typical Diagram of Coal Based Power Plant

Its various parts are listed below:-

1. Cooling tower

2. Cooling water pump

3. Transmission line (3-phase)

4. Unit transformer (3-phase)

5. Electric generator (3-phase)

6. Low pressure turbine

7. Condensate extraction pump

8. Condenser


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9. Intermediate pressure turbine

10. Steam governor valve

11. High pressure turbine

12. DE aerator13. Feed heater

13. Coal conveyor

14. Coal hopper

15. Pulverised fuel mill

16. Boiler drum

17. Ash hopper

18. Super heater

19. Forced draught fan

20.Re heater

21. Air intake

22.Economiser

23.Air preheater

24.Precipitator

25.Induced draught fan

27. Fuel Gas Stack


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1. Cooling towers

Cooling Towers are evaporative coolers used for cooling water or other working medium to near the

ambivalent web-bulb air temperature. Cooling tower use evaporation of water to reject heat from

processes such as cooling the circulating water used in oil refineries, Chemical plants, power plants

and building cooling, for example. The tower vary in size from small roof-top units to very largehyperboloid structures that can be up to 200 meters tall and 100 meters in diameter, or rectangular

structure that can be over 40 meters tall and 80 meters long. Smaller towers are normally factory built,

while larger ones are constructed on site. The primary use of large , industrial cooling tower system is

to remove the heat absorbed in the circulating cooling water systems used in power plants , petroleum

refineries, petrochemical and chemical plants, natural gas processing plants and other industrial

facilities . The absorbed heat is rejected to the atmosphere by the evaporation of some of the cooling

water in mechanical forced-draft or induced draft towers or in natural draft hyperbolic shaped cooling

towers as seen at most nuclear power plants.

2. Cooling Water Pump

It pumps the water from the cooling tower which goes to the condenser.

3.Three phase transmission line

Three phase electric power is a common method of electric power transmission. It is a type of poly

phase system mainly used to power motors and many other devices. A Three phase system uses less

conductor material to transmit electric power than equivalent single phase, two phase, or direct

current system at the same voltage. In a three phase system, three circuits reach their instantaneous

peak values at different times. Taking one conductor as the reference, the other two current are

delayed in time by one-third and two-third of one cycle of the electrical current. This delay betweenphases has the effect of giving constant power transfer over each cycle of the current and alsomakes it possible to produce a rotating magnetic field in an electric motor. At the power station, an

electric generator converts mechanical power into a set of electric currents, one from each

electromagnetic coil or winding of the generator. The current are sinusoidal functions of time, all at

the same frequency but offset in time to give different phases. In a three phase system the phases are

spaced equally, giving a phase separation of one-third one cycle. Generators output at a voltage that

ranges from hundreds of volts to 30,000 volts.

4. Unit transformer (3-phase)

At the power station, transformers: step-up this voltage to one more suitable for transmission. Afternumerous further conversions in the transmission and distribution network the power is finally

transformed to the standard mains voltage (i.e. the household voltage).

The power may already have been split into single phase at this point or it may still be three phase.

Where the step-down is 3 phase, the output of this transformer is usually star connected with the

standard mains voltage being the phase-neutral voltage. Another system commonly seen in North

America is to have a delta connected secondary with a centre tap on one of the windings supplying the

ground and neutral. This allows for 240 V three phase as well as three different single phase voltages

( 120 V between two of the phases and neutral , 208 V between the third phase ( known as a wild leg)

and neutral and 240 V between any two phase) to be available from the same supply.


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5. Electrical generator

An Electrical generator is a device that converts kinetic energy to electrical energy, generally using

electromagnetic induction. The task of converting the electrical energy into mechanical energy is

Accomplished by using a motor. The source of mechanical energy may be a reciprocating or turbine

steam engine, , water falling through the turbine are made in a variety of sizes ranging from small

1hp (0.75 kW) units (rare) used as mechanical drives for pumps, compressors and other shaft driven

equipment, to 2,000,000 hp (1,500,000 kW) turbines used to generate electricity. There are several

Classifications for modern steam turbines.

Steam turbines are used in all of our major coal fired power stations to drive the generators or

alternators, which produce electricity. The turbines themselves are driven by steam generated inBoilers or steam generators as they are sometimes called.Electrical power station use large steam turbines driving electric generators to produce most (about

86%) of the worlds electricity. These centralized stations are of two types: fossil fuel power plantsand nuclear power plants. The turbines used for electric power generation are most often directly

coupled to their-generators .As the generators must rotate at constant synchronous speeds according

to the frequency of the electric power system, the most common speeds are 3000 r/min for 50 Hzsystems, and 3600 r/min for 60 Hz systems. Most large nuclear sets rotate at half those speeds, and

have a 4-pole generator rather than the more common 2-pole one.

6. Low Pressure Turbine

Energy in the steam after it leaves the boiler is converted into rotational energy as it passes through

the turbine. The turbine normally consists of several stage with each stages consisting of a stationary

blade (or nozzle) and a rotating blade. Stationary blades convert the potential energy of the steam into

kinetic energy into forces, caused by pressure drop, which results in the rotation of the turbine shaft.

The turbine shaft is connected to a generator, which produces the electrical energy.

Low Pressure Turbine (LPT) consist of 4x2 stages. After passing through Intermediate Pressure

Turbine is passed through LPT which is made up of two parts- LPC REAR & LPC FRONT. As water

gets cooler here it gathers into a HOTWELL placed in lower parts of Turbine.

7. Condensation Extraction Pump

A Boiler feed water pump is a specific type of pump used to pump water into a steam boiler. The

water may be freshly supplied or retuning condensation of the steam produced by the boiler. These

pumps are normally high pressure units that use suction from a condensate return system and can be

of the centrifugal pump type or positive displacement type.

Construction and operation

Feed water pumps range in size up to many horsepower and the electric motor is usually separated from the

pump body by some form of mechanical coupling. Large industrial condensate pumps may also serve as the

feed water pump. In either case, to force the water into the boiler; the pump must generate sufficient pressure to

overcome the steam pressure developed by the boiler. This is usually accomplished through the use of a

centrifugal pump.

Feed water pumps usually run intermittently and are controlled by a float switch or other similar level-sensingdevice energizing the pump when it detects a lowered liquid level in the boiler is substantially increased. Some

pumps contain a two-stage switch. As liquid lowers to the trigger point of the first stage, the pump is activated. If the liquid continues to drop (perhaps because the pump has failed, its supply has been cut off or exhausted, or


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its discharge is blocked); the second stage will be triggered. This stage may switch off the boiler equipment

(preventing the boiler from running dry and overheating), trigger an alarm, or both.

8.Condenser

The steam coming out from the Low Pressure Turbine (a little above its boiling pump) is Brought intothermal contact with cold water (pumped in from the cooling tower) in the condenser, whereit condenses rapidly back into water, creating near vacuum-like conditions inside the condenser

chest.

9. Intermediate Pressure Turbine

Intermediate Pressure Turbine (IPT) consist of 11 stages. When the steam has been passedthrough HPT it gets enter into IPT. IPT has two ends named as FRONT & REAR. Steam enters

through frontend and leaves from Rear end.

10. Steam Governor Valve

Steam locomotives and the steam engines used on ships and stationary applications such as power plants also

required feed water pumps. In this situation, though, the pump was often powered using a small steam engine

that ran using the steam produced by the boiler. A means had to be provided, of course, to put the initial charge

of water into the boiler (before steam power was available to operate the steam-powered feed water pump).thepump was often a positive displacement pump that had steam valves and cylinders at one end and feed water

cylinders at the other end; no crank shaft was required.

In thermal plants, the primary purpose of surface condenser is to condense the exhaust steam from a steamturbine to obtain maximum efficiency and also to convert the turbine exhaust steam into pure water so that it

may be reused in the steam generator or boiler as boiler feed water. By condensing the exhaust steam ofa turbine at a pressure below atmospheric pressure, the steam pressure drop between the inlet and exhaust of the

turbine is increased, which increases the amount heat available for conversion to mechanical power. Most of the

heat liberated due to condensation of the exhaust steam is carried away by the cooling medium (water or air)

used by the surface condenser.

Control valves are valves used within industrial plants and elsewhere to control operating conditions such astemperature ,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 sensors that

monitor changes in such conditions. The opening or closing of control valves is done by means of electrical,

hydraulic or pneumatic systems

11.High Pressure Turbine

Steam coming from Boiler directly feeds into HPT at a temperature of 540C and at a pressureof 136 kg/cm2. Here it passes through 12 different stages due to which its temperature goesdown to329C and pressure as 27 kg/cm2. This line is also called as CRH COLD REHEAT LINE

It is now passed to an REHEATER where its temperature rises to 540C and called as HRH-HOTREHEATED LINE .


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12. Dearator

A 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 dearator 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 feed water 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 willdeposit 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 level by regulating condensate

flow and the pressure by regulating steam flow. If operated properly, most deaerator vendors will guarantee that

oxygen in the deaerated water will not exceed 7 ppb by weight (0.005cm3/L)

13. 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.[4] 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 modelled 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 reversibilitys associated

with heat transfer to the working fluid (water). A belt conveyor consists of two pulleys, with a continuous loop

of material- the conveyor Beltthat 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.

14. Coal conveyor

Coal conveyors are belts which are used to transfer coal from its storage place to Coal Hopper.

15. Coal Hopper

Coal Hopper are the places which are used to feed coal to Fuel Mill. It also has the arrangementof entering of Hoy Air at 200C inside it which solves our two purposes:-

1. If our Coal has moisture content then it dries it so that a proper combustion takes place.

2. It raises the temperature of coal so that its temperature is more near to its IgniteTemperature so that combustion is easy


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16. Pulverised Fuel Mill

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

17. Boiler Drum

Steam 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 in the water tubes and act as a phase separator

for the steam/water mixture. The difference in densities between hot and cold water helps in the accumulation of

the hotter-water/and saturatedsteam into steam drum. Made from high-grade steel (probably stainless) andits working involves temperatures 390C and pressure well above 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 the furnace 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.

18. Ash Hopper

A steam drum is used in the company 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.

19. Super Heater

A Super heater is a device in a steam engine that heats the steam generated by the boiler 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 20thcentury, to most steam vehicles, and so stationary steam

engines including power stations.

20. Force Draught Fan

External fans are provided to give sufficient air for combustion. The forced draft fan takesair from the atmosphere and, first warming it in the air pre heater for better combustion,injects it via the air nozzles on the furnace wall.

21. Reheater

Reheater are heaters which are used to raise the temperature of air which has been fallen down due to various

process.

22. Air Intake

Air is taken from the environment by an air intake tower.

23. Economizers

Economizer, or in the UK economizer, are mechanical devices intended to reduce energy consumption, or toperform another useful function like preheating a fluid. The term economizer issued for other purposes as

well. Boiler, power plant, and heating, ventilating and air conditioning.


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In boilers, economizer are heat exchange devices that heat fluids , usually water, up to but not normally beyond

the boiling point of the fluid. Economizers are so named because they can make use of the enthalpy and

improving the boilers efficiency. They are a device fitted to a boiler which saves energy by using the exhaustgases from the boiler to preheat the cold water used the fill it (the feed water). Modern day boilers, such as those

in cold fired power stations, are still fitted with economizer which is decedents of Greens original design. In

this context they are turbines before it is pumped to the boilers. A common application of economizer is steam

power plants is to capture the waste hit from boiler stack gases (flue gas) and transfer thus it to the boiler feedwater thus lowering the needed energy input , in turn reducing the firing rates to accomplish the rated boiler

output . Economizer lower stack temperatures which may cause condensation of acidic combustion gases andserious equipment corrosion damage if care is not taken in their design and material selection.

24. Air Preheater

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 allowing simplified design

of the ducting and the flue gas stack. It also allows control over the temperature of gases leaving the stack.

25. Precipitator

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 catalyst collection from fluidized bed catalytic crackers from several hundred thousand ACFM in the

largest coal-fired boiler application.

The original parallel plate-Weighted wire design (described above) has evolved as more efficient (and robust)

discharge 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,

avoiding damage 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.

26. Induced Draught Fan

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 anyopening. At the furnace outlet, and before the furnace gases are handled by the ID fan, finedust carried by the outlet gases is removed to avoid atmospheric pollution. This is anenvironmental limitation prescribed by law, additionally minimizes erosion of the ID fan.


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27. Fuel gas stack

A Fuel gas stack is a type of chimney, a vertical pipe, channel or similar structure through whichcombustion product gases called fuel gases are exhausted to the outside air. Fuel gases areproduced when coal, oil, natural gas, wood or any other large combustion device. Fuel gas is

usually composed of carbon dioxide(CO2) and water vapour as well as nitrogen and excess oxygenremaining from the intake combustion air. It also contains a small percentage of pollutants suchas particulates matter, carbon mono oxide, nitrogen oxides and sulphur oxides. The flue gasstacks are often quite tall, up to 400 meters (1300 feet) or more, so as to disperse the exhaustpollutants over a greater aria and thereby reduce the concentration of the pollutants to thelevels required by governmental environmental policies and regulations. When the fuel gasesexhausted from stoves, ovens, fireplaces or other small sources within residential abodes,restaurants , hotels or other stacks are referred to as chimneys


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OPERATION OF BOILER

The 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 rapidlyburns, forming a large fireball at the centre. The thermal radiation of the fireball heatsthe water that circulates through the boiler tubes near the boiler perimeter. The watercirculation rate in the boiler is three to four times the throughput and is typically driven bypumps. As the water in the boiler circulates it absorbs heat and changes into steam at 700F (370 C) and 22.1 MPa. It is separated from the water inside a drum at the top ofthe furnace. The saturated steam is introduced into superheat pendant tubes that hang in thehottest part of the combustion gases as they exit the furnace. Here the steam is superheatedto 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 temperaturerequired for the steam turbine that drives the electrical generator. The generator includes theeconomizer, the steam drum, the chemical dosing equipment, and the furnace with its steamgenerating tubes and the super heater coils. Necessary safety valves are located at suitablepoints to avoid excessive boiler pressure. The air and flue gas path equipment include: forceddraft(FD) fan, air preheater (APH), boiler furnace, induced draft (ID) fan, fly ash collectors(electrostatic precipitator or bughouse) and the flue gas stack.

Schematic diagram of a coal-fired power plant steam generator


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Boiler Furnace and Steam Drum

Once water inside the boiler or steam generator, the process of adding the latent heatof vaporization or enthalpy is underway. The boiler transfers energy to the water by the

chemical reaction of burning some type of fuel. The water enters the boiler through a sectionin the convection pass called the economizer. From the economizer it passes to the steam drum. Oncethe 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 intosteam due to the heat being generated by 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.

Fuel Preparation System

In coal-fired power stations, the raw feed coal from the coal storage area is first crushed intosmall pieces and then conveyed to the coal feed hoppers at the boilers. The coal is nextpulverized into a very fine powder. The pulverizers may be ball mills, rotating drum grinders, orother types of grinders. Some power stations burn fuel oil rather than coal. The oil must keptwarm (above its pour point) in the fuel oil storage tanks to prevent the oil from congealing andbecoming un-pumpable.The oil is usually heated to about 100C before being pumped through thefurnace fuel oil spray nozzles.

Fuel Firing System and Ignite System

From the pulverized coal bin, coal is blown by hot air through the furnace coal burners at anangle which imparts a swirling motion to the powdered coal to enhance mixing of the coal powderwith the incoming preheated combustion air and thus to enhance the combustion. To providesufficient combustion temperature in the furnace before igniting the powdered coal, thefurnace 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 airfrom the atmosphere and, first warming it in the air preheated for better combustion, injects itvia the air nozzles on the furnace wall. The induced draft fan assists the FD fan by drawing outcombustible gases from the furnace, maintaining a slightly negative pressure in the furnace toavoid backfiring through any opening. At the furnace outlet, and before the furnace gases arehandled by the ID fan, fine dust carried by the outlet gases is removed to avoid atmosphericpollution. This is an environmental limitation prescribed by law, and additionally minimizeserosion of the ID fan.


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Fly Ash Collection

Fly ash is captured and removed from the flue gas by electrostatic precipitators or fabric bagfilters (or sometimes both) located at the outlet of the furnace and before the induced draftfan. 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 subsequenttransport by trucks or railroad cars.

Bottom Ash Collection and Disposal

At the bottom of every boiler, a hopper has been provided for collection of the bottom ashfrom the bottom of the furnace. This hopper is always filled with water to quench the ash andclinkers falling down from the furnace. Some arrangement is included to crush the clinkers andfor 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 theboiler, losses due to blow-down and leakages have to be made up for so as to maintain thedesired water level in the boiler steam drum. For this, continuous make-up water is added to theboiler water system. The impurities in the raw water input to the plant generally consist ofcalcium and magnesium salts which impart hardness to the water. Hardness in the make-upwater to the boiler will form deposits on the tube water surfaces which will lead to overheatingand failure of the tubes. Thus, the salts have to be removed from the water and that is done bya water demineralising treatment plant (DM).

OPERATION OF TURBINE

Steam turbines are used in all of our major coal fired power stations to drive the generators oralternators, which produce electricity. The turbines themselves are driven by steam generatedin Boilers' or 'Steam Generators' as they are sometimes called. Energy in the steam after itleaves the boiler is converted into rotational energy as it passes through the turbine. Theturbine normally consists of several stages with each stage consisting of a stationary blade (ornozzle) and a rotating blade. Stationary blades convert the potential energy of the steam

(temperature and pressure) into kinetic energy (velocity) and direct the flow onto the rotatingblades. The rotating blades convert the kinetic energy into forces, caused by pressure

drop, which results in the rotation of the turbine shaft. The turbine shaft is connected toa generator, which produces the electrical energy. The rotational speed is 3000 rpm for IndianSystem (50 Hz) systems and 3600 for American (60 Hz)systems.

In a typical larger power stations, the steam turbines are split into three separate stages, thefirst being the High Pressure (HP), the second the Intermediate Pressure (IP) and the third theLow-pressure (LP) stage, where high, intermediate and low describe the pressure of the steam.After the steam has passed through the HP stage, it is returned to the boiler to be re-heatedto its original temperature although the pressure remains greatly reduced. The reheated steam

then passes through the IP stage and finally to the LP stage of the turbine.High-pressure oil is injected into the bearings to provide lubrication.


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CONTROL & INSTRUMENTATION

INTRODUCTION

C&I LABS

CONTROL & MONITORING MECHENISM

PRESSURE MONITORING

TEMPERATURE MONITORING

FLOW MEASUREMENT

CONTROL VALVES


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INTRODUCTION

This division basically calibrates various instruments and takes care of any faults occur in anyof the auxiliaries in the plant.

Instrumentation can be well defined as a technology of using instruments to measure andcontrol the physical and chemical properties of a material.

C&I LABS

Control and Instrumentation Department has following labs:

1. Manometry Lab

2. Protection and Interlocks Lab

3. Automation Lab

4. Electronics Lab

5. Water Treatment Plant

6. Furnaces Safety Supervisory System Lab

OPERATION AND MAINTENANCE

Control and Instrumentation Department has following Control Units:

1. Unit Control Board

2. Main Control Board

3. Analog & Digital Signal Control

4. Current Signal Control

This department is the brain of the plant because from the relays to transmitters followed by theelectronic

computation chipsets and recorders and lastly the controlling circuitry, all fall under this.

A View Control Room at BTPS


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1.Manometer Lab

TRANSMITTERS

It is used for pressure measurements of gases and liquids, its working principle is that the input

pressure is converted into electrostatic capacitance and from there it is conditioned and amplified. Itgives an output of 4-20 ma DC. It can be mounted on a pipe or a wall. For liquid or steam

measurement transmitters is mounted below main process piping and for gas measurement transmitter

is placed above pipe.

MANOMETER

Its a tube which is bent, in U shape. It is filled with a liquid. This device corresponds to a

difference in pressure across the two limbs.

BOURDEN PRESSURE GAUGE

Its an ovalsection tube. Its one end is fixed. It is provided with a pointer to indicate thepressure on a calibrated scale. It is of 2 types:-

(a) Spiral type: for Low pressure measurement.

(b) Helical Type: for High pressure measurement.

While selecting Pressure Gauge these parameters should keep in mind.

-Accuracy

-Safety

-Utility

-Price

ACCURACY

Higher Accuracy implies Larger Dial Size for accuracy of small and readable pressure scale

increments.

SAFETY

While selecting Pressure Gauge it should consider that Gauge Construction Material should bechemically compatible with the environment either inside or outside it.

UTILITY

It should keep it mind that range of the Gauge should be according to our need elseOverpressure Failure may occur resulting in damage of Gauge.

PRICE

Lager the Gauges Dial size larger would be our price. Better Gauges Construction material alsoincreases the cost. So they must be chosen according to our need.


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2.Protection and Interlock Lab

INTERLOCKING

It is basically interconnecting two or more equipments so that if one equipment fails other onecan perform the tasks. This type of interdependence is also created so that equipments

connected together are started and shut down in the specific sequence to avoid damage. Forprotection of equipments tripping are provided for all the equipments. Tripping can beconsidered as the series of instructions connected through OR GATE, which trips the circuit.The main equipments of this labare relay and circuit breakers. Some of the instrument uses forprotection are:-

RELAY

It is a protective device. It can detect wrong condition in electrical circuits by constantlymeasuring the electrical quantities flowing under normal and faulty conditions. Some of theelectrical quantities are voltage, current, phase angle and velocity. 2. FUSES It is a short pieceof metal inserted in the circuit, which melts when heavy current flows through it and thus

breaks the circuit.

Usually silver is used as a fuse material because:

a) The coefficient of expansion of silver is very small. As a result no critical fatigue occursand thus the continuous full capacity normal current ratings are assured for the longtime.

b) The conductivity of the silver is unimpaired by the surges of the current that producestemperatures just near the melting point.

c) Silver fusible elements can be raised from normal operating temperature to vaporizationquicker than any other material because of its comparatively low specific heat.

Miniature Circuit Breaker

They are used with combination of the control circuits to.

a) Enable the staring of plant and distributors.

b) Protect the circuit in case of a fault. In consists of current carrying contacts, onemovable and other fixed. When a fault occurs the contacts separate and are is stuck

between them.There are three types of trips

I. MANUAL TRIPII. THERMAL TRIP

III. SHORT CIRCUIT TRIP.

Protection and Interlock System-

1. HIGH TENSION CONTROL CIRCUIT for high tension system the control system areexcited by separate D.C supply. For starting the circuit conditions should be in series withthe starting coil of the equipment to energize it. Because if even a single condition is not truethen system will not start.


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2.LOW TENSION CONTROL CIRCUIT For low tension system the control circuits are directlyexcited from the 0.415 KV A.C supply.

The same circuit achieves both excitation and tripping. Hence the tripping coil is provided foremergency tripping if the interconnection fails.

3.AUTOMATION LABThis lab deals in automating the existing equipment and feeding routes. Earlier, the oldtechnology dealt with only (DAS) Data Acquisition System and came to be known as primarysystems. The modern technology or the secondary systems are coupled with (MIS) ManagementInformation System. But this lab universally applies the pressure measuring instruments as thecontrolling force. However, the relays are also provided but they are used only for protectionand interlocks.

4.PYROMETRY LAB

LIQUID IN GLASS THERMOMETER

Mercury in the glass thermometer boils at 340 C which limits the range of temperature thatcan be measured. It is L shaped thermometer which is designed to reach all inaccessible places.

1. ULTRA VIOLET CENSOR-

This device is used in furnace and it measures the intensity of ultra violet rays there andaccording to the wave generated which directly indicates the temperature in the furnace.

2, THERMOCOUPLES

This device is based on SEEBACK and PELTIER effect. It comprises of two junctions atdifferent temperature. Then the emf is induced in the circuit due to the flow of electrons. Thisis an important part in the plant.

3. RTD (RESISTANCE TEMPERATURE DETECTOR)

It performs the function of thermocouple basically but the difference is of a resistance. Inthis due to the change in the resistance the temperature difference is measured. In thislab, also the measuring devices can be calibrated in the oil bath or just boiling water (for lowrange devices) and in small furnace (for high range devices).

5.FURNACE SAFETY AND SUPERVISORY SYSTEM LAB

This lab has the responsibility of starting fire in the furnace to enable the burning of coal. Forfirst stage coal burners are in the front and rear of the furnace and for the second andthird stage corner firing is employed. Unburnt coal is removed using forced draft or induceddraft fan. The temperature inside the boiler is 1100C and its heights 18 to 40 m. It is made upof mild steel. An ultra violet sensor is employed in furnace to measure the intensity of ultraviolet rays inside the furnace and according to it a signal in the same order of same mV isgenerated which directly indicates the temperature of the furnace. For firing the furnace a

10 KV spark plug is operated for ten seconds over a spray of diesel fuel and pre-heater air along


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each of the feeder-mills. The furnace has six feeder mills each separated by warm air pipes fedfrom forced draft fans.In first stage indirect firing is employed that is feeder mills are not fed directly from coal butare fed from three feeders but are fed from pulverized coalbunkers. The furnace can operateon the minimum feed from three feeders but under no circumstances should anyone be left

out under operation, to prevent creation of pressure different within the furnace, whichthreatens to blast it.

6.ELECTRONICS LABThis lab undertakes the calibration and testing of various cards. It houses various types ofanalytical instruments like oscilloscopes, integrated circuits, cards auto analyzers etc.Variousprocesses undertaken in this lab are:1. Transmitter converts mV to mA.2. Auto analyzer purifies the sample before it is sent to electrodes. It extracts the magneticportion.

ANNUNCIATIN CARDS

They are used to keep any parameter like temperature etc. within limits. It gets a signalif parameter goes beyond limit. It has a switching transistor connected to relay that helps inalerting the UCB.

CONTROL & MONITORING MECHANISMS

There are basically two types of Problems faced in a Power Plant.

1. Metallurgical

2. Mechanical

Mechanical Problem can be related to Turbines that is the max speed permissible for a turbineis3000 rpm so speed should be monitored and maintained at that level.Metallurgical Problem canbe view as the max Inlet Temperature for Turbine is 1060 C sotemperature should be belowthe limit. Monitoring of all the parameters is necessary for the safetyof both:

1. Employees

2. MachinesSo the Parameters to be monitored are:

1. Speed

2. Temperature

3. Current

4. Voltage

5. Pressure


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6. Eccentricity

7. Flow of Gases

8. Vacuum Pressure

9. Valves

10. Level

11. Vibration

PRESSURE MONITORING

Pressure can be monitored by three types of basic mechanisms

1. Switches

2. Gauges

3. Transmitter type

For gauges we use Bourdon tubes. The Bourdon Tube is a non-liquid pressure measurementdevice. It is widely used in applications where inexpensive static pressure measurements areneeded. A typical Bourdon tube contains a curved tube that is open to external pressure input onone end and is coupled mechanically to an indicating needle on the other end, as shown

schematically below.

Typical Bourdon Tube Pressure Gauge

For Switches pressure switches are used and they can be used for digital means ofmonitoring as switch being ON is referred as high and being OFF is as low.All the monitored data is converted to either Current or Voltage parameter.

The Plant standard for current and voltage are as under

Voltage: 0 10 Volts range Current: 4- 20 milli-Amperes


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We use 4mA as the lower value so as to check for disturbances and wire breaks.

Accuracy of such systems is very high.

ACCURACY : 0.1 %

Programmable Logic Circuits (PLCs) are used in the process as they are the heart ofInstrumentation.

TEMPERATURE MONITORING

We can use Thermocouples or RTDs for temperature monitoring. Normally RTDs are used for

low temperatures.Thermocouple selection depends upon two factors:

1. Temperature Range

2. Accuracy Required

Normally used Thermocouple is K Type Thermocouple:

In this we use Chromel (Nickel-Chromium Alloy) / Alumel (Nickel-Aluminium Alloy) as two metals.This is the most commonly used general purpose thermocouple. It is inexpensive and, owing to itspopularity, available in a wide variety of probes. They are available in the 200C to +1200Crange. Sensitivity is approximately 41 V/C.

RTDs are also used but not in protection systems due to vibrational errors.We pass a constant current through the RTD. So that if R changes then the Voltage alsochanges.

RTDs used in Industries are Pt100and Pt1000

Pt100 : 0C 100 ( 1 = 2.5 0C )

Pt1000 : 0C -1000

Pt1000 is used for higher accuracy.

The gauges used for Temperature measurements are mercury filled Temperature gauges.

For Analog medium thermocouples are used and for Digital medium Switches are used which arebasically mercury switches.


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FLOW MEASUREMENT

Flow measurement does not signify much and is measured just for metering purposes and formonitoring the processes

ROTAMETERS:

A Rotameter is a device that measures the flow rate of liquid or gas in a closed tube. It isoccasionally misspelled as 'Rotometer'.

It belongs to a class of meters called variable area meters, which measure flow rate by allowingthe cross sectional area the fluid travels through to vary, causing some measurable effect. Arotameter consists of a tapered tube, typically made of glass, with a float inside that is pushedup by flow and pulled down by gravity. At a higher flow rate more area (between the float and

the tube) is needed to accommodate the flow, so the float rises. Floats are made in manydifferent shapes, with spheres and spherical ellipses being the most common. The float is

shaped so that it rotates axially as the fluid passes. This allows you to tell if the float is stucksince it will only rotate if it is not.

For Digital measurements Flap system is used.

For Analog measurements we can use the following methods :

1. Flow meters

2. Venturimeters / Orifice meters

3. Turbines

4. Mass flow meters( oil level )

5. Ultrasonic Flow meters

6. Magnetic Flow meter( water level )

Selection of flow meter depends upon the purpose, accuracy and liquid to be measured so

different types of meters used.

TURBINE TYPE:

They are simplest of all. They work on the principle that on each rotation of the turbine a pulseis generated and that pulse is counted to get the flow rate.


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VENTURIMETERS :

Referring to the diagram, using Bernoulli's equation in the special case of incompressiblefluids (such as the approximation of a water jet), the theoretical pressure drop at the

Constriction would be given by(/2)(v22- v12).And we know that rate of flow is given by:Flow = k (D.P)

Where DP is Differential Pressure or the Pressure Drop.

CONTROL VALVES

A valve is a device that regulates the flow of substances (either gases, fluidized solids,

slurries, or liquids) by opening, closing, or partially obstructing various passageways. Valves aretechnically pipe fittings, but usually are discussed separately. Valves are used in a varietyof applications including industrial, military, commercial, residential, transportation. Plumbingvalves are the most obvious in everyday life, but many more are used.

Some valves are driven by pressure only, they are mainly used for safety purposes in steamengines and domestic heating or cooking appliances. Others are used in a controlled way, like inOtto cycle engines driven by a camshaft, where they play a major role in engine cycle control.

Many valves are controlled manually with a handle attached to the valve stem. If the handle is

turned a quarter of a full turn (90) between operating positions, the valve is called a quarter-turn valve. Butterfly valves, ball valves, and plug valves are often quarter-turn valves. Valves canalso be controlled by devices called actuators attached to the stem. They canbe electromechanical actuators such as an electric motor or solenoid, pneumatic actuatorswhichare controlled by air pressure, or hydraulic actuators which are controlled by the pressure of aliquid such as oil or water. So there are basically three types of valves that are used in powerindustries besides the handle valves.They are :

PNEUMATIC VALVES -They are air or gas controlled which is compressed to turn or move them

HYDRAULIC VALVES- They utilize oil in place of Air as oil has better compression


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MOTORISED VALVES -These valves are controlled by electric motors

FURNACE SAFEGUARD SUPERVISORY SYSTEM

FSSS is also called as Burner Management System (BMS). It is a microprocessor basedprogrammable logic controller of proven design incorporating all protection facilities requiredfor such system. Main objective of FSSS is to ensure safety of the boiler.

The 95 MW boilers are indirect type boilers. Fire takes place in front and in rear side. Thatswhy its called front and rear type boiler.

The 210 MW boilers are direct type boilers (which means that HSD is in direct contact with

coal) firing takes place from the corner. Thus it is also known as corner type boiler.

IGNITER SYSTEM

Igniter system is an automatic system, it takes the charge from 110kv and this spark isbrought in front of the oil guns, which spray aerated HSD on the coal for coal combustion.There is a 5 minute delay cycle before igniting, this is to evacuate or burn the HSD. Thismethod is known as PURGING.

PRESSURE SWITCH

Pressure switches are the devices that make or break a circuit. When pressure is applied, the

switch under the switch gets pressed which is attached to a relay that makes or break thecircuit.

Time delay can also be included in sensing the pressure with the help of pressure valves.Examples of pressure valves:

1. Manual valves (tap)2. Motorized valves (actuator) works on motor action3. Pneumatic valve (actuator) _ works due to pressure of compressed air4. Hydraulic valve

Documents

Summer Traning Report 6