ashish ntpc

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2011

VOCATIONAL TRAINING REPORT

ROHIT KUMAR

ECE (7th Sem)

ABES IT ,Ghaziabad

Roll No. 0829031414


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TABLE OF CONTENT

1. ACKNOWLEDGEMENT

2. TRAINING CERTIFICATE

3. ABOUT THE COMPANY

4. BRIEF HISTORY OF THE POWER PLANT (BADARPUR)

5. THERMAL POWER PLANT

6. CONTROL & INSTRUMENTATION:- Manometry lab:- Protection and interlocks lab:- Automation lab:- Electronics lab:- Water treatment plant:- Furnaces Safety Supervisory System Lab

7. INFORMATION AND TECHNOLOGY


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ACKNOWLEDGEMENT

I hereby take this opportunity to thank NTPC Ltd. Badarpur for giving me thisopportunity to conduct my

training in NTPC Ltd., Badarpur. I am grateful toMr. Sudhir Kumar (P&S) for allowing me to conduct

my training in thecontrol & Instrumentation department. I am heartly indebted to thefaculty forproviding me with detailed in depth knowledgeand very useful information about the processes and

systems used in the plant. Their support was instrumental in my training being fruitful . I am avery

thankful to all the officers and staff ofNTPC Ltd., Badarpur for extending ahelping hand whenever needed

Furthermore, I seek extreme pleasure in expressing my feelings of indebtedness toMr Rakesh Gupta, MrPrempal, Mr R.S.Dabar, Mr Mukesh Kumarand Mr Chetan Singh for their guidanceduring the training.

ASHISH KUMAR SWAMI

ELECTONICS AND COMMUNICATION ENGINEE

ABES INSTITUTE OF TECHNOLOGY, GHAZIA


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INTRODUCTION

NTPC is the largest power generation company in India, with comprehensive in-house capabilities inbuilding and operating power projects. It is producing 31,704MW (INCLUDEING 2864MW UNDER JVs.With a current generating capacity of 31134 MW, NTPC has embarked on plans to become a 75,000

MW company by 2017. It was founded on November 7, 1975.Its family consists of 18 coal based powerplant producing (23209 MW) and 8 gas based power plant having a capacity of (5435 mw). It is also setting up ahydro based power plants having capacityof 2471MW. It is one of the largest Indian companies with a market capof more than US$50 BILLION and has total assets of around US$ 20 BILLION. In this firm government has89.5% stake and 10.5% with public. NTPC is ranked 463rd biggest company in the world, 5th biggest Indiancompany and 2nd largest Asian power generator. It produces 26350MW which is 20.18%of the total 130,539MW ofall India consumption. More than one-fourth of Indias generation with one-fifth capacity. The next largestpower utility owns 7.9% of market share in terms ofcapacity and 8.12% of share in terms of units generated. NTPCsvision is to become world classintegrated power major, powering Indias growth, with increasing globalpresence. It also develops and provides reliable power, related products and services at competitive prices,integrating multiple energy sources with innovative and eco-friendly technologies andcontributes to

society. This firm is also well concern about the environmental factors.NTPC has set new benchmarks forthe power industry both in the area of power plant construction and operations. Its providing power atthe cheapest average tariff in the country.NTPC is committed to the environment, generating power atminimal environmental cost and preserving the ecology in the vicinity of the plants. NTPC hasundertaken massive a forestation in the vicinity of its plants. Plantations have increased forest area andreduced barren land. The massive a forestation by NTPC in and around its Ramagundam Power station(2600 MW) have contributed reducing the temperature in the areas by about 3c. NTPC has also takenproactive steps forash utilization. In 1991, it set up Ash Utilization Division.

A "Centre for Power Efficiency and Environment Protection (CENPEEP)" has been established inNTPC with the assistance of United States Agency for International Development. (USAID). Cenpeep is

efficiency oriented, eco-friendly and eco-nurturing initiative - a symbol of NTPC's concern towardsenvironmental protection and continued commitment to sustainable power development in India. As aresponsible corporate citizen, NTPC is making constant efforts to improve the socio-economic status ofthe people affected by its projects. Through its Rehabilitation and Resettlement programmes, thecompany endeavors to improve the overall socio economic status Project Affected Persons. NTPC wasamong the first Public Sector Enterprises to enter into a Memorandum of Understanding (MOU) withthe Government in 1987-88. NTPC has been placed under the 'Excellent category' (the best category)every year since the MOU system became operative .Harmony between man and environment is theessence of healthy life and growth. Therefore, maintenance of ecological balance and a pristineenvironment has been of utmost importance to NTPC. It has been taking various measures discussed below for mitigation of environment pollution due to power generation .Environment Policy &

Environment Management System Driven by its commitment for sustainable growth of power, NTPChas evolved a well defined environment management policy and sound environment practices forminimizing environmental impact arising out of setting up of power plants and preserving the naturalecology. National Environment Policy: At the national level, the Ministry of Environment and Forestshad prepared a draft Environment Policy (NEP) and the Ministry of Power along with NTPC activelyparticipated in the deliberations of the draft NEP. The NEP 2006 has since been approved by the UnionCabinet in May 2006. NTPC Environment Policy: As early as in November 1995, NTPC brought out acomprehensive document entitled "NTPC Environment Policy and Environment Management System".Amongst the guiding principles adopted in the document are company's proactive approach toenvironment, optimum utilization of equipment, adoption of latest technologies and continual
http://www.ntpc.co.in/operations/operations.shtmlhttp://www.ntpc.co.in/infocus/environment.shtmlhttp://www.ntpc.co.in/infocus/ashutilisation.shtmlhttp://www.ntpc.co.in/otherlinks/cenpeep.shtmlhttp://www.ntpc.co.in/infocus/socialcomm.shtmlhttp://www.ntpc.co.in/operations/operations.shtmlhttp://www.ntpc.co.in/infocus/environment.shtmlhttp://www.ntpc.co.in/infocus/ashutilisation.shtmlhttp://www.ntpc.co.in/otherlinks/cenpeep.shtmlhttp://www.ntpc.co.in/infocus/socialcomm.shtml


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environment improvement. The policy also envisages efficient utilization of resources, therebyminimizing waste, maximizing ash utilization and providing green belt all around the plant formaintaining ecological balance. Environment Management, Occupational Health and Safety Systems:NTPC has actively gone for adoption of best international practices on environment, occupational healthand safety areas.

The organization has pursued the Environmental Management System (EMS) ISO 14001 and theOccupational Health and Safety Assessment System OHSAS 18001 at its different establishments. As aresult of pursuing these practices, all NTPC power stations have been certified for ISO 14001 & OHSAS18001 by reputed national and international Certifying Agencies. Pollution Control systems: Whiledeciding the appropriate technology for its projects, NTPC integrates many environmental provisionsinto the plant design.

In order to ensure that NTPC comply with all the stipulated environment norms, various state-of-the-artpollution control systems / devices as discussed below have been installed to control air and waterpollution. Electrostatic Precipitators: The ash left behind after combustion of coal is arrested in highefficiency Electrostatic Precipitators (ESPs) and particulate emission is controlled well within thestipulated norms. The ash collected in the ESPs is disposed to Ash Ponds in slurry form. Flue GasStacks: Tall Flue Gas Stacks have been provided for wide dispersion of the gaseous emissions (SOX,NOX etc) into the atmosphere. Low-NOX Burners: In gas based NTPC power stations, NOX emissionsare controlled by provision of Low-NOX Burners (dry or wet type) and in coal fired stations, byadopting best combustion practices. Neutralization Pits: Neutralization pits have been provided in theWater Treatment Plant (WTP) for pH correction of the effluents before discharge into EffluentTreatment Plant (ETP) for further treatment and use. Coal Settling Pits / Oil Settling Pits : In these Pits,coal dust and oil are removed from the effluents emanating from the Coal Handling Plant (CHP), coalyard 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 fired power stations in NTPC tocontain and extract the fugitive dust released in the Coal Handling Plant (CHP). 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 allcoal based stations except Dadri where Dry Ash Disposal System has been provided. Ash Ponds havebeen divided into lagoons and provided with garlanding arrangements for change over of the ash slurryfeed 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 the slurry and cleareffluent water is discharged from the ash pond. The discharged effluents conform to standards specifiedby CPCB and the same is regularly monitored. At its Dadri Power Station, NTPC has set up a uniquesystem for dry ash collection and disposal facility 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 lessrequirement of land and less water requirement as compared to the wet ash disposal system.Ash WaterRecycling System: Further, in a number of NTPC stations, as a proactive measure, Ash Water RecyclingSystem (AWRS) has been provided.

In the AWRS, the effluent from ash pond is circulated back to the station for further ash sluicing to theash pond. This helps in savings of fresh water requirements for transportation of ash from the plant. Theash water recycling system has already been installed and is in operation at Ramagundam, Simhadri,Rihand, Talcher Kaniha, Talcher Thermal, Kahalgaon, Korba and Vindhyachal. The scheme has helpedstations to save usage quantity of fresh water required a smake- aterforisposalofash. Dry Ash ExtractionSystem(DAES): Dry ash has much higher utilization potential in ash-based products (such as bricks,


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aerated autoclaved concrete blocks, concrete, Portland pozzolana cement, etc.). DAES has been installedat Unchahar, Dadri, Simhadri, Ramagundam, Singrauli, Kahalgaon, Farakka, Talcher Thermal,Korba,Vindhyachal, TalcherKanihaand BTPS.Liquid Waste Treatment Plants&Management System: Theobjective of industrial liquid effluent treatment plant (ETP) is to discharge lesser and cleaner effluentfrom the power plants to meet environmental regulations. After primary treatment at the source of theirgeneration, the effluents are sent to the ETP for further treatment. The composite liquid effluenttreatment plant has been designed to treat all liquid effluents which originate within the power statione.g. Water Treatment Plant (WTP), Condensate Polishing Unit (CPU) effluent, Coal Handling Plant(CHP) effluent, floor washings, service water drains etc. The scheme involves collection of variouseffluents and their appropriate treatment centrally and re-circulation of the treated effluent for variousplant uses.NTPC has implemented such systems in a number of its power stations such as Ramagundam,Simhadri, Kayamkulam, Singrauli, Rihand, Vindhyachal, Korba, Jhanor Gandhar, Faridabad, Farakka,Kahalgaon and Talcher Kaniha.

These plants have helped to control quality and quantity of the effluents discharged from the stations.Sewage Treatment Plants & Facilities: Sewage Treatment Plants (STPs) sewage treatment facilities havebeen provided at all NTPC stations to take care of Sewage Effluent from Plant and township areas. In anumber of NTPC projects modern type STPs with Clarifloculators, Mechanical Agitators, sludge dryingbeds, Gas Collection Chambers etc have been provided to improve the effluent quality. The effluentquality is monitored regularly and treated effluent conforming to the prescribed limit is discharged fromthe station. At several stations, treated effluents of STPs are being used for horticulture purpose.

Environmental Institutional Set-up: Realizing the importance of protection of the environment withspeedy development of the power sector, the company has constituted different groups at project,regional and Corporate Centre level to carry out specific environment related functions. TheEnvironment Management Group, Ash Utilisation Group and Centre for Power Efficiency &Environment Protection (CENPEEP) function from the Corporate Centre and initiate measures tomitigate the impact of power project implementation on the environment and preserve ecology in thevicinity of the projects. Environment Management and Ash Utilization Groups established at eachstation, look after various environmental issues of the individual station. Environment Reviews: Tomaintain constant vigil on environmental compliance, Environmental Reviews are carried out at alloperating stations and remedial measures have been taken wherever necessary. As a feedback andfollow-up of these Environmental Reviews, a number of retrofit and up-gradation measures have beenundertaken at different stations. Such periodic Environmental Reviews and extensive monitoring ofthe facilities carried out at all stations have helped in compliance with the environmental norms andtimely renewal of the Air and Water Consents. Up gradation & retro fitting of Pollution ControlSystems: Waste Management Various types of wastes such as Municipal or domestic wastes, hazardouswastes, Bio-Medical wastes get generated in power plant areas, plant hospital and the townships ofprojects. The wastes generated are a number of solid and hazardous wastes like used oils & waste oils,grease, lead acid batteries, other lead bearing wastes (such as garkets etc.), oil & clarifier sludge, used

resin, used photo-chemicals, asbestos packing, e-waste, metal scrap, C&I wastes, electricial scrap,empty cylinders (refillable), paper, rubber products, canteen (bio-degradable) wastes, buidling materialwastes, 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 perclassification given in Government of Indias notification on Hazardous Wastes (Management andHandling) Rules 1989 (as amended on 06.01.2000 & 20.05.2003). Handling and management of thesewastes in NTPC stations have been discussed below. Advanced / Eco-friendly Technologies NTPC hasgained expertise in operation and management of 200 MW and 500 MW Units installed at differentStations all over the country and is looking ahead for higher capacity Unit sizes with super critical steam


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parameters for higher efficiencies and for associated environmental gains. At Sipat, higher capacityUnits of size of 660 MW and advanced Steam Generators employing super critical steam parametershave already been implemented as a green field project. Higher efficiency Combined Cycle Gas PowerPlants are already under operation at all gas-based power projects in NTPC. Advanced clean coaltechnologies such as Integrated Gasification Combined Cycle (IGCC) have higher efficiencies of theorder of 45% as compared to about 38% for conventional plants. NTPC has initiated a techno-economicstudy under USDOE / USAID for setting up a commercial scale demonstration power plant by usingIGCC technology. These plants can use low-grade coals and have higher efficiency as compared toconventional plants. With the massive expansion of power generation, there is also growing awarenessamong all concerned to keep the pollution under control and preserve the health and quality of thenatural environment in the vicinity of the power stations. NTPC is committed to provide affordable andsustainable power in increasingly larger quantity. NTPC is conscious of its role in the nationalendeavour of mitigating energy poverty, heralding economic prosperity and thereby contributingtowards Indias emergence as a major global economy. Lay out of Employees

THERMAL POWER PLANT

A thermal power station consists of all the equipments and a subsystem required to produceelectricity by using a steam generating boiler fired with fossil fuels or befouls to drive anelectric generator. Some prefer to use the term ENERGY CENTER because such facilitiesconvert form of energy like nuclear energy, gravitational potential energy or heat energy(derived from the combustion of fuel) into electrical energy. Typical diagram of a coal powerthermal power station-

1. Cooling water pump2. Three phase transmission line3. Step up transformer4. Electrical generator

5. Low pressure steam6. Boiler feed water pump7. Surface condenser8. Intermediate pressure steam turbine9. Steam control valve10.High pressure steam turbine11.Deaerator feed water heater12.Coal conveyer13.Coal hopper14.Coal pulverizer15.Boiler steam drum

16.Boiler ash hopper17.Super heater18.Force draught (draft) fan19.Reheater20.Combustion air intake21.Economiser22.Airpreheater23.Precipitator24.Induced draught(draft) fan25.Fuel gas stack

The description of some of the components above is as follows:


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Cooling towers

Cooling towers are eveporative coolers used for cooling water. Cooling tower use evaporationof water to reject heat from processes such as cooling the circulaing water used in oilrefineries, chemical plants, power plants, etc. The tower vary in size from small roof - topunits to very large hyperboloid structures that can be upto 200 meters tall and 100 meters in

diameter, or rectangular structure that can be over 40 meters tall and 80 meters long. Smallertowers are normally factory built while larger ones are constructed on site. The primary use oflarge, industrial cooling tower system is to remove the heat absorbed in the circulating watersystem used in power plants, petroleum refineries, petrochemical and chemical plants, naturalgas processing plants and other industrial facilities.The absorbed heat is rejected to the atmosphere by the evaporation of some of the coolingwater in mechanical forced - draft or induced draft towers or in natural draft hyperbolicshaped cooling towers as seen at most nuclear power plants.

Three phase transmission line

Three phase electric power is a common method of electric power transmission. It is a type ofpolyphase system mainly used for power motors and many other devices. In a three phasesystem,three circuits reach their instantaneous peak values at different times. Taking oneconductor as reference, the other two conductor are delayed in time by one-third and two-third of cycle of the electrical current. This delay between phases has the effect of givingconstant power over each cycle of the current and also makes it impossible to produce arotating magnetic field in an electric motor. At the power station, an electric generatorconverts mechanical power into a set of electric currents one from each electromagnetic coilor winding of the generator. The currents are sinusoidal functions of time, all at the samefrequency 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 of one cycle. Generators output at avoltage that ranges from hundreds of volts to 30,000 volts. At the power station. Transformersstep-up this voltage for suitable transmission. After numerous further conversions in thetransmission and distribution network, the power is finally transformed to standard mainsvoltage i.e. the household voltage. The power may already have been split into single phaseat this point or it may be still three phase. Where the step-down is three phase. The output ofthe transformer is usually star connected with the standard mains voltage being the phaseneutral voltage.

Electrical generator

An electrical generator is a device that coverts mechanical energy to electrical energy, usingelectromagnetic induction whereas electrical energy is converted to mechanical energy withthe help of electric motor. The source of mechanical energy may be a reciprocating turbinesteam engine. Turbines are made in variety of sizes ranging from small 1 hp(0.75 kW) used asmechanical drives for pumps, compressors and other shaft driven equipment to 2,000,000hp(1,500,000 kW) turbines used to generate electricity.


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Boiler Feed Pump

A Boiler Feed Pump is a specific type of pump used to pump water into steam boiler. Thewater may be freshly supplied or retuning condensation of steam produced by the boiler.These pumps are normally high pressure units that use suction from a condensate returnsystem and can be of centrifugal pump type or positive displacement type. Construction andOperation feed water pumps range in size upto many horsepower and the electric motor isusually 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 water intothe boiler, the pump must generate sufficient pressure to overcome the steam pressuredeveloped by the boiler. This is usually accomplished through the use of centrifugal pump.Feed water pumps usually run intermittently and are controlled by a float switch or othersimilar level-sensing device energizing the pump when it detect a lowered liquid level in the

boiler substantially increased. Some pumps contain a two stage switch. As liquid lowers tothe 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 itsdischarge is blocked),the second stage will be triggered. This stage may switch off the boilerequipment (preventing the boiler from running dry and overheating), trigger an alarm orboth.

Control valves-

Control Valves are the valves used within industrial plants and elsewhere to control operatingconditions such as temperature, pressure, flow and liquid level by fully or partially openingor closing in response to signals received from controllers that compares a set point to aprocess variable whose value is provided by sensors that monitor changes in suchconditions. The opening or closing of control valves is done by means of electrical, hydraulicor pneumatic systems.

Deaerator

A Deaerator is a device for air removal and used to remove dissolved gases from boiler feedwater to make it non-corrosive. A deaerator typically includes a vertical domed deaerationsection as the deaeration feed water tank. A steam generating boiler requires that thecirculating steam, condensate and feed water should be devoid of dissolved gases, particularlycorrosive ones and dissolved or suspended solids. The gases will give rise to corrosion of themetal. The solids will deposit on heating surfaces giving rise to localized heating and tube

ruptures due to overheating. Deaerator level and pressure must be controlled by adjustingcontrol valves-the level by regulating condensate flow and pressure by regulating steamflow. Most deaerators guarantee that if operated properly, oxygen in deaerated water will notexceed 7ppb by weight.

Feed Water Heater

A feed water heater is a power plant component used to pre heat water delivered to a steamgenerating boiler. Feed water heater improves the efficiency of the system. This reduces plantoperating costs and also helps to avoid thermal shock to boiler metal when the feed water isintroduced back into the steam cycle. Feed water heaters allow the feed water to be brought

upto the saturation temperature very gradually. This minimizes the inevitable irreversibility


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associated with heat transfer to the working fluid(water). A belt conveyer consistsof two pulleys, with a continuous loop of material- the conveyer belt that rotates aroundthem. The pulleys are powered, moving the belt and the material on the belt forward.Conveyer belts are extensively used to transport industrial and agricultural material, such asgrain, coal, ores, etc.

8. Pulverizer

A pulverizer is a device for grinding coal for combustion in a furnace in a fossil fuel powerplant.

9. Boiler Steam Drum

Steam Drums are a regular feature of water tube boilers. It is reservoir of water/steam at thetop end of the water tubes in the water-tube boiler. They store the steam generated in thewater tubes and act as a phase separator for the steam/water mixture. The difference indensities between hot and cold water helps in the accumulation of the hotter-water/and

saturated -steam into steam drum. Made from high-grade steel (probably stainless) and itsworking involves temperatures 390C and pressure well above 350psi (2.4MPa). The separatedsteam is drawn out from the top section of the drum. Saturated steam is drawn off the top ofthe drum. The steam will re-enter the furnace in through a super heater, while the saturatedwater at the bottom of steam drum flows down to the mud- drum /feed water drum by downcomer tubes accessories include a safety valve, water level indicator and fuse plug. A steamdrum is used in the company of a mud-drum/feed water drum which is located at a lowerlevel. So that it acts as a sump for the sludge or sediments which have a tendency tothe bottom.

10. Super Heater

A Super heater is a device in a steam engine that heats the steam generated by the boiler againincreasing its thermal energy and decreasing the likelihood that it will condense inside theengine. 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-superheatedsteam is called saturated steam or wet steam; Super heaters were applied to steam locomotivesin quantity from the early 20th century, to most steam vehicles, and so stationary steamengines including power stations.

11. Economizers

Economizer, or in the UK economizer, are mechanical devices intended to reduce energyconsumption, or to perform another useful function like preheating a fluid. The termeconomizer is used for other purposes as well. Boiler, power plant, and heating, ventilatingand air conditioning. 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 areso 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 exhaust gases from the

boiler to preheat the cold water used the fill it (the feed water). Modern day boilers, such asthose in cold fired power stations, are still fitted with economizer which is decedents ofGreens original design. In this context they are turbines before it is pumped to theboilers. A common application of economizer is steam power plants is to capture the waste


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hit from boiler stack gases (flue gas) and transfer thus it to the boiler feed water thuslowering the needed energy input , in turn reducing the firing rates to accomplish the rated

boiler output . Economizer lower stack temperatures which may cause condensationof acidic combustion gases and serious equipment corrosion damage if care is not taken intheir design and material selection.

12. Air Preheater

Air preheater is a general term to describe any device designed to heat air before anotherprocess (for example, combustion in a boiler).

The purpose of the air preheater is to recover the heat from the boiler flue gas whichincreases 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 lowertemperature allowing simplified design of the ducting and the flue gas stack. It also allowscontrol over the temperature of gases leaving the stack.

13. Precipitator

An Electrostatic precipitator (ESP) or electrostatic air cleaner is a particulate device thatremoves particles from a flowing gas (such As air) using the force of an induced electrostaticcharge. Electrostatic precipitators are highly efficient filtration devices, and can easilyremove fine particulate matter such as dust and smoke from the air steam. ESPs continue tobe excellent devices for control of many industrial particulate emissions, including smokefrom electricity- generating utilities (coal and oil fired), salt cake collection from blackliquor boilers in pump mills, and catalyst collection from fluidized bed catalytic crackersfrom 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 ( androbust) discharge electrode designs were developed, today focusing on rigid dischargeelectrodes to which many sharpened spikes are attached , maximizing corona production.Transformer -rectifier systems apply voltages of 50-100 Kilovolts at relatively high currentdensities. Modern controls minimize sparking and prevent arcing, avoiding damage to thecomponents. Automatic rapping systems and hopper evacuation systems remove the collectedparticulate matter while on line allowing ESPs to stay in operation for years at a time.

14. 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 gasesare produced when coal, oil, natural gas, wood or any other large combustion device. Fuel gasis usually composed of carbon dioxide (CO2) and water vapor as well as nitrogen and excessoxygen remaining from the intake combustion air. It also contains a small percentage ofpollutants such as particulates matter, carbon mono oxide, nitrogen oxides and sulfur oxides.The flue gas stacks are often quite tall, up to 400 meters (1300 feet) or more, so as to dispersethe exhaust pollutants over a greater aria and thereby reduce the concentration of the

pollutants to the levels required by governmental environmental policies and regulations.


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Electricity Generation Process(A Basic Overview)

At NTPC (Badarpur) the man two paths are the flue gas or air cycle and steam or condensate paths.

Capital Overhaul

NTPC has been in news due to extensive load sheds in many areas in delhi and the main cause behindthese load sheds was the capital overhaul of one of 210 MW units. Unit IV was under an extensive check ,which has caused shut down of the plant and the plant, was dismantled completely to change the old partsand cleaning up the whole unit. But capital overhaul has no meaning because such a deep checking of theplant happens once in five to seven years.

How Electricity Is Generated

Thermal power station burns fuel and uses the resultant heat to raise steam which drives the TURBOGENERATOR. The fuel may be fossil(coal,oil,natural gas) or it may be fissionable, whichever fuel is

used, the objective is same to convert the mechanical energy into electricity by rotating a magnet inside aset of winding.

Coal To Steam

Its other raw materials are air and water. The coal brought to the station by trains or by other means,travels handling plant by conveyer belts, travels from pulverizing mills, which grind it as fine as the facepowder of size upto 20 microns. The finely produced coal mixed with preheated air is then blown into theboiler by a fan called primary air fan where it burns more like a gas than as a solid, in the conventionaldomestic or industrial grate, with additional amount of air, called secondary air supply, by forced draft fan.

As coal is ground so finally the resultant ash is also a fine powder. Some of it binds together to formpumps, which falls into ash pits at the bottom of the furnace. The waterquenched ash from the bottom isconveyed to pits for subsequent disposal or sale. Most of ash, still in fine partical form is carried out ofboilers to the precipitator as dust, where electrodes charged with high voltage electricity trap it. The dust isthen conveyed to water to disposal area or to bunker for sale while the clean flue gases are passed onthrough IP fans to be discharged through chimneys.

The heat released from the coal has been absorbed by the many kilometers tubing which line the boilerwalls. Inside the tubes the boiler feed water, which is transformed by heat into staemat high temperatureand pressure.. The steam superheated in further tubes (superheaters) passes to turbine where it isdischarged through the nozzle on the turbine blades. Just as the energy of wind turns the sail of the

windmill, the energy of steam striking the blade makes the turbine rotate.Coupled to the end of the turbine is the rotor of the generator. The rotor is housed inside the stator havingheavy coils of the bars in which electricity is produced through the movement of magnetic field created bythe rotor. Electricity passes from stator windings to step-up transformer which increases its voltage so thatit can be transmited efficiently over lines of grid.

The staem which has given up its heat energy is cahnged back into water in a condenser so that it is readyfor re-use. The condenser contains many kilometers of tubing through which cold water is constantlypumped. The staem passing around the tubes looses heat.Thus it is rapidly changed back into water.

But, the two lots of water, that is, the boiler feed and cooling water must never mix. Cooling water isdrawn from river- bed, but the boiler feed water must be absolutely pure, far purer than the water we drink


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(de-mineralized water), otherwise it may damage the boiler tubes.


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TABLES OF CYCLES

COAL CYCLE


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CONDENSATE CYCLE


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FEED WATER CYCLE


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STEAM CYCLE


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Control And Instrumentation

This division basically calibrates various instruments and takes care ofany faults occur in anyof the auxiliaries in the plant.This department is the brain of the plant because from the relaysto transmitters followed by the electronic computation chipsets and recorders and lastly thecontrolling circuitry, all fall under this.

Instrumentation can be well defined as a technology of using instruments to measure and control thephysical and chemical properties of a material.

Control and instrumentation has following labs:

1. Manometry lab2. Protection and interlocks lab3. Automation lab4. Electronics lab5. Water treatment plant6. Furnaces Safety Supervisory System Lab

1. Manometry lab

Transmitters- Transmitter 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 isconditioned and amplified. It gives an output of 4-20 ma DC. It can be mounted on a pipe or a wall. Forliquid or steam measurement transmitters is mounted below main process piping and for gas measurementtransmitter is placed above pipe.

Manometer- Its a tube which is bent, in U shape. It is filled with a liquid. This device corresponds toa difference in pressure across the two limbs. Bourden Pressure Gauge- Its an oval section tube. Its one end is fixed. It is provided with a pointer

to indicate the pressure on a calibrated scale. It is of two types : (a) Spiral type: for low pressuremeasurement and (b) Helical type : for high pressure measurement

2. Protection and Interlock Lab

Interlocking- It is basically interconnecting two or more equipments so that if one equipments failsother one can perform the tasks.

This type of interdependence is also created so that equipments connected together are started and shutdown in the specific sequence to avoid damage. For protection of equipments tripping are provided for allthe equipments. Tripping can be considered as the series of instructions connected through OR GATE.

When The main equipments of this lab are relay and circuit breakers. Some of the instrument uses forprotection are: 1. RELAY It is a protective device. It can detect wrong condition in electrical circuits byconstantly measuring 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 piece of metalinserted 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 occurs and thus the continuous full capacity normal current ratings areassured for the long time. b) The conductivity of the silver is unimpaired by the surges of the current thatproduces temperatures just near the melting point. c) Silver fusible elements can be raised from normaloperating temperature to vaporization quicker than any other material because of its comparatively lowspecific heat.


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Miniature Circuit Breaker- They are used with combination of the control circuits to. a) Enable thetaring of plant and distributors. b) Protect the circuit in case of a fault. In consists of current carryingontacts, one movable and other fixed. When a fault occurs the contacts separate and are is stuck betweenthem. There are three types of trips viz. Annual trip, Thermal trip and Short Circuit Trip.

Protection and Interlock System- 1. HIGH TENSION CONTROL CIRCUIT for high tension system thecontrol system are excited by separate D.C supply. For starting the circuit conditions should be in serieswith the starting coil of the equipment to energize it. Because if even a single condition is not true thensystem will not start. 2. LOW TENSION CONTROL CIRCUIT For low tension system the control circuitsare directly excited from the 0.415 KVA .C supply. The same circuit achieves both excitation and tripping.Hence the tripping coil is provided for emergency tripping if the interconnection fails.

3.Automation Lab

This lab deals in automating the existing equipment and feeding routes. Earlier, the old technology dealtwith only (DAS) Data Acquisition System and came to be known as primary systems. The moderntechnology or the secondary systems are coupled with (MIS) Management Information System. But thislab universally applies the pressure measuring instruments as the controlling force. However, the relays arealso provided but they are used only for protection and interlocks.

4.Pyrometry Lab Liquid in glass thermometer - Mercury in the glass thermometer boils at 340 degree Celsius which

limits the range of temperature that can be measured. It is L shaped thermometer which is designed toreach all inaccessible places.

Ultra violet censor- This device is used in furnace and it measures the intensity of ultra violet raysthere and according to the wave generated which directly indicates the temperature in the furnace.

Thermocouples - This device is based on SEEBACK and PELTIER effect. It comprises of twojunctions at different temperature. Then the emf is induced in the circuit due to the flow of electrons. Thisis an important part in the plant.

RTD(Resistance temperature detector) - It performs the function of thermocouple basically but thedifference is of a resistance. In this due to the change in the resistance the temperature difference ismeasured. In this lab, also the measuring devices can be calibrated in the oil bath or just boiling water (forlow range 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. For first stagecoal burners are in the front and rear of the furnace and for the second and third stage corner firing isemployed. Unburnt coal is removed using forced draft or induced draft fan. The temperature inside the

boiler is 1100 degree Celsius and its height is 18 to 40 m. It is made up of mild steel. An ultra violet sensoris employed in furnace to measure the intensity of ultra violet rays inside the furnace and according to it asignal in the same order of same mV is generated which directly indicates the temperature of thefurnace.

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 each of the feeder-mills. The furnace has six feeder mills each separated by warm air pipesfed from forced draft fans. In first stage indirect firing is employed that is feeder mills are not fed directlyfrom coal but are fed from three feeders but are fed from pulverized coalbunkers. The furnace can operateon the minimum feed from three feeders but under not circumstances should any one be left out underoperation, to prevent creation of pressure different with in the furnace, which

threatens to blast it.


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6. Electronics Lab

This lab undertakes the calibration and testing of various cards. It houses various types of analyticalinstruments like oscilloscopes, integrated circuits, cards auto analyzers etc.Various processes undertaken inthis lab are: 1. Transmitter converts mV to mA. 2. Auto analyzer purifies the sample before it is sent toelectrodes. It extracts the magnetic portion.

AUTOMATION AND CONTROL SYSTEMAutomation: The Definition

The word automation is widely used today in relation to various types of applications, such as officeautomation, plant or process automation.

This subsection presents the application of a control system for the automation of a process / plant, such asa power station. In this last application, the automation actively controls the plant during the three mainphases of operation: plant start-up, power generation in stable or put During plant start-up and shut-down,sequence controllers as well as long range modulating controllers in or out of operation every piece of the

plant, at the correct time and in coordinated modes, taking into account safety as well as overstressing limits.During stable generation of power, the modulating portion of the automation system keeps the actualgenerated power value within the limits of the desired load demand.

During major load changes, the automation system automatically redefines new set points and switchesON or OFF process pieces, to automatically bring the individual processes in an optimally coordinatedway to the new desired load demand. This load transfer is executed according to pre- programmedadaptively controlled load gradients and in a safe way.

Automation: The Benefits

The main benefits of plant automation are to increase overall plant availability and efficiency. The increaseof these two factors is achieved through a series of features summarized as follows:

Optimisation of house load consumption during plant start- up, shut-down and operation, via:

Faster plant start-up through elimination of control errors creating delays. Faster sequence of control actions compared to manual ones. Figures 1 shows the sequence of a rapid

restart using automation for a typical coal-fired station. Even a well- trained operator crew wouldrobably not be able to bring the plant to full load in the same time without considerable risks.

Co-ordination of house load to the generated power output.

Ensure and maintain plant operation, even in case of disturbances in the control system, via: Coordinated ON / OFF and modulating control switchover capability from a sub process to a

redundant one. Prevent sub-process and process tripping chain reaction following a process component trip.

Reduce plant / process shutdown time for repair and maintenance as well as repair costs,via: Protection of individual process components against overstress (in a stable or unstable plant operation). Bringing processes in a safe stage of operation, where process components are protected against

overstress


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Process Structure

Analysis of processes in Power Stations and Industry advocates the advisability of dividing the complexoverall process into individual sub-processes having distinctly defined functions. This division of theprocess in clearly defined groups, termed as FUNCTIONAL GROUPS, results in a hierarchical processstructure. While the hierarchical structure is governed in the horizontal direction by the number of drives(motorised valves, fans, dampers, pumps, etc.) in other words the size of the process; in the verticaldirection, there is a distinction made between three fundamental levels, these being the: -

Drive Level

Function Group Level

Unit Level.

To the Drive Level, the lowest level, belong the individual process equipment and associated electricaldrives.

The Function Group is that part of the process that fulfils a particular defined task e.g., Induced DraftControl, Feed Water Control, Blooming Mill Control, etc. Thus at the time of planning it is necessary toidentify each function group in a clear manner by assigning it to a particular process activity. Eachfunction group contains a combination of its associated individual equipment drives. The drive levels aresubordinate to this level. The function groups are combined to obtain the overall process control functionat the Unit Level.

The above three levels are defined with regard to the process and not from the control point of view.Control System Structure

The primary requirement to be fulfilled by any control system architecture is that it be capable of beingorganized and implemented on true process-oriented lines. In other words, the control system structureshould map on to the hierarchy process structure. BHELs PROCONTROL P, a microprocessor basedintelligent remote multiplexing system, meets this requirement completely.

System Overview

The control and automation system used here is a micro based intelligent multiplexingsystem This system, designed on a modular basis, allows to tighten the scope of controlhardware to the particular control strategy and operating requirements of the process. Regardless of thetype and extent of process to control provides system uniformity and integrity for:

Signal condition in grand transmission Modulating controls


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CONTROL AND MONITORING MECHANISMS

There are basically two types of Problems faced in a Power PlantMetallurgical

Mechanical

Mechanical Problemcan be related to Turbines that is the max speed permissible for a turbine is 3000rpm , so speed should be monitored and maintained at that level Metallurgical Problem can be view as themax Inlet Temperature for Turbile is 1060 oC so temperature should be below the limit.

Monitoring of all the parameters is necessary for the safety of both:

Employees

Machines

So the Parameters to be monitored are :

Speed

Temperature

Current

Voltage

Pressure

Eccentricity

Flow of Gases

Vaccum Pressure

Valves

Level

Vibration


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PRESSURE MONITORING

Pressure can be monitored by three types of basic mechanisms

Switches

Gauges

Transmitter type

For gauges we use Bourden tubes : The Bourdon Tube is a non liquid pressure measurement device. It iswidely used in applications where inexpensive static pressure measurements are needed.

A typical Bourdon tube contains a curved tube that is open to external pressure input on one end and iscoupled mechanically to an indicating needle on the other end, as shown schematically below.

Typical Bourdon Tube Pressure Gages

For Switches pressure swithes are used and they can be used for digital means of monitoring as swithbeing ON is referred as high and being OFF is as low. All the monitored data is converted to eitherCurrent or Voltage parameter. The Plant standard for current and voltage are as under

Voltage : 0 - 10 Volts range

Current : 4 - 20 milliAmperes

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 %

The whole system used is SCADA baseD.Programmable Logic Circuits ( PLCs) are used in the process as they are the heardt of Instrumentation .


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BASIC PRESSURE CONTROL MECHANISM

Pressure

Electricity

Electricity

Electricity

HL switchStartLevel low Pressurein lineLevel High LLswitch

pumpStopPressure

AND

High level

OR


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TEMPERATURE MONITORINGWe can use Thernocouples or RTDs for temperature monitoring Normally RTDs are used for lowtemperatures.

Thermocoupkle selection depends upon two factors: Temperature Range Accuracy Required

Normally used Thermocouple is K Type Thermocouple:

Chromel (Nickel-Chromium Alloy) / Alumel (Nickel-Aluminium Alloy)

This is the most commonly used general purpose thermocouple. It is inexpensive and, owing to its

popularity, available in a wide variety of probes. They are available in the 200 C to +1200 C range.Sensitivity is approximately 41 V/C.

RTDs are also used but not in protection systems due to vibrational errors.

We pass a constant curre t through the RTD. So that if R changes then the Voltage also changes

RTDs used in Industries are Pt100 and Pt1000

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

Pt1000 : 0 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 are basically mercury switches.


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FLOW MEASUREMENTFlow measurement does not signify much and is measured just for metering purposes and for monitoringthe processes

ROTAMETERS:

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

It belongs to a class of meters called variable area meters, which measure flow rate by allowing the crosssectional area the fluid travels through to vary, causing somemeasurable effect.

A rotameter consists of a tapered tube, typically made of glass, with a float inside that is pushed up byflow 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 many different shapes, with spheresand spherical ellipses being the most common. The float is shaped so that it rotates axially as the fluidpasses. This allows you to tell if the float is stuck since it will only rotate if it is not.

For Digital measurements Flap system is used.

For Analog measurements we can use the following methods :

Flowmeters

Venurimeters / Orifice meters

Turbines

Massflow meters ( oil level )

Ultrasonic Flow meters

Magnetic Flowmeter ( water level )

Selection of flow meter depends upon the purpose , accuracy and liquid to be measured so different typesof meters used.

Turbine type are the simplest of all.

They work on the principle that on each rotation of the turbine a pulse is generated and that pulse iscounted to get the flow rate.


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VENTURIMETERS :


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Referring to the diagram, using Bernoulli's equation in the special case of incompressible fluids (such asthe 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 Presure 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 are technically pipe fittings, butusually are discussed separately.

Valves are used in a variety of applications including industrial, military, commercial, residential,

transportation. Plumbing valves 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 steam engines anddomestic heating or cooking appliances. Others are used in a controlled way, like in Otto cycle enginesdriven 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 aquarter of a full turn (90) between operating positions, the valve is called a quarter-turn valve. Butterflyvalves, ball valves, and plug valves are often quarter-turn valves. Valves can also be controlled by devicescalled actuators attached to the stem. They can be electromechanical actuators such as an electric motor orsolenoid, pneumatic actuators which are controlled by air pressure, or hydraulic actuators which arecontrolled by the pressure of a liquid such as oil or water.

So there are basically three types of valves that are used in power industries besides the handle valves.They are : Pneumatic Valves - they are air or gas controlled which is compressed to turn

or move themHydraulic valves - they utilize oil in place of Air as oil has better

compression

Motorised valves - these valves are controlled by electric motors

Furnace Safeguard Supervisory SystemFSSS is also called as Burner Management System (BMS). It is a microprocessor basedprogrammablelogic controller of proven design incorporating all protection facilities required for such system. Mainobjective 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. Thats why itscalled front and rear type boiler.

The 210 MW boilers are direct type boilers (which means that HSD is in direct contactwith coal) firing takes place from the corner. Thus it is also known as corner type boiler.


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Igniter System

Igniter system is an automatic system, it takes the charge from 110kv and this spark is brought infront of the oil guns, which spray aerated HSD on the coal for coal combustion. There is a 5minute delay cycle before igniting, this is to evacuate or burn the HSD. This method is known asPURGING.

PRESSURE SWITCHPressure switches are the devices that make or break a circuit. When pressure is applied , the switchunder the switch gets pressed which is attached to a relay that makes or break the circuit. Time delay canalso 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 action

3. Pneumatic valve (actuator) _ works due to pressure of compressed air

4. Hydraulic valve


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INFORMATION AND TECHNOLOGY

IT Role @ BTPS

1.Development,implementation,maintenance and support for local applications.Planning,procurrement and maintenance of IT Infrastructure

(PCs,Printers, Scanners and network LAN/WAN etc._)3.ERP support and modules for supplement ERP.

Implementing support of BTPS for other projects.

Company Wide Communication Network1. NTPC is among very few companies to have its own satellite basedcommunication network.

2. The network is expanding and maintaining with the expansion of theCompany.3. All the projects are directly connected to the network.

Achievements And Improvements1. Network upgradation with recharging links and standby devices.2. Multiple WAN links for redundancy.3. Replacement of old PCs and peripherals with new and latest ones.4. Improvements and achievement it IT applications.

ERP/SAP modules implemented

Maintenance Management (MM)Finance Management (FM)Material Management (MM)Human Resource Management (HR)Employee Self Service (ESS)Operational Management (OPM)Coal Maintenance and AccountingContracts MaintenanceOffice maintenance and communication


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BTPS IT Highlights

ERP implementation support

Year 2008 has been an eventful and challenging year. ERP was implemented in year 2008. Migration of legacy applications data. Personal, Loans and payroll data of over 1500 employees. Huge savings of man days and efforts of users. ERP training labs were set up to impart hands on training to users. Materials (30000+ items) and vendors (5000+) data. Accountbalances of finance.

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