1. SUMMER TRAINING REPORT AT UTTPAR PRADESH RAJAY VIDUAT UTPADAN NIGAM LIMITED ANPARA SONEBHADRA ON THERMEL POWER PLANT Submitted for partial fulfillment of award of BACHELOR OF TECHNOLOGY IN MECHANICAL ENGINEERING UNDER THE SUPERVISION OF:- COLLEGE INCHARGE:- ER.SAMIR BHATNAGAR DR. B D SAHOO (EXECUTIVE ENGINEER B.M.D. I) (H.O.D OF ME DEPARTMENT) SUBMITTED BY:- RAGHWENDRA KU. PATHAK B.TECH ME 3rd YEAR REGD. NO. 1101320106

2. Acknowledgment The result of all engineering efforts whatever from they take a direct outcome of not just an individuals thinking but represents the organization. The same view holds good this seminar report. I extended my sincere gratitude towards Er. SAMIR BHATNAGAR SIR (EXECUTIVE ENGINEERING B.M.D.I, BTPS) for giving us invaluable knowledge & Technical guidance. I would like to thanks Er. SAMIR BHATNAGAR SIR (EXECUTIVE ENGINEER B.M.D.I, BTPS) for giving me their kind co-operation & inspiration to do my seminar work. I also thanks all the staff members and my friends for their endless Help and support. NAME OF THE STUDENT:- RAGHWENDRA KU. PATHAK REGD.NO. 1101320106 BRANCH:-ME 3rd YEAR 3. Certificate This is certified that RAGHWENDRA KU. PATHAK student of Mechanical Engineering from Aryan Institute of Engineering & Technology, Bhubaneswar has carried out his summer training work during 7 MAY 2014 to 6 JUNE 2014 presented in this report entitled (THERMAL POWER PLANT) under my supervision of Er. SAMIR BHATNAGAR (EXECUTIVE ENGINEER B.M.D.I BTPS) and his entire team. Er. SAMIR BHATNAGAR (EXECUTIVE ENGINEER B.M.D.I BTPS) 4. Abstract A thermal power station is a power plant in which the prime mover is steam driven. Water is heated, turns into steam and spins a steam turbine which drives an electrical generator. After it passes through the turbine, the steam is condensed in a condenser and recycled to where it was heated; this is known as a Rankine cycle. The greatest variation in the design of thermal power stations is due to the different fuel sources. Some prefer to use the term energy center because such facilities convert forms of heat energy into electricity. Some thermal power plants also deliver heat energy for industrial purposes, for district heating, or for desalination of water as well as delivering electrical power. A large part of human CO2 emissions comes from fossil fueled thermal power plants; efforts to reduce these outputs are various and widespread. At present 54.09% or 93918.38 MW (Data Source CEA, as on 31/03/2011) of total electricity production in India is from Coal Based Thermal Power Station. A coal based thermal power plant converts the chemical energy of the coal into electrical energy. This is achieved by raising the steam in the boilers, expanding it through the turbine and coupling the turbines to the generators which converts mechanical energy into electrical energy. 5. Contents PROJECT 1 OBJECTIVES......2 BRIEF HISTORY/INTRODUCTION OF ORGANIZATION...3 ORGANIZATIONAL CHART...5 PLANT LAYOUT...6 PRODUCTS AND SPECIFICATION7 PRODUCT FLOW CHART8 CHRONOLOGICAL TRAINING DIARY11 PRODUCTION PROCESS12 TURBINE23 210 MW TURBINES IN PARICCHA32 MARKETING STRATEGIES37 DIVERSIFICATION OR EXPANSION38 SUGGESTIONS..39 CONCLUSION....40 6. Project To study the general concepts and working of thermal power plant, and its components, especially turbine. 1 7. Brief history This is a project run under Uttar Pradesh Rajya Vidhyut Utpadan Nigam Ltd.UPRVUNL is wholly owned state thermal power utility with present generating capacity of 4082MW, operating 5 Thermal Power Stations within Uttar Pradesh. Poised to contribute in the growth of state, we're in the process of adding further 2000 MW capacity to our existing fleet by year 2012. The name of this power project is paricha thermal power project its foundation war laid in 1979 and it started producing electricity in 1983. It is a state owned semi government project. It has four units which are generating electricity. Two no of 250MW which are likely to be completed tip to year 2011. Total installed capacity of the plant at present is 640 mw. The total installed capacity of the plant will be 1140 mw in the year 2011 presently it is thermal power project of UPRVUNL. This project is thermal based power project in which combustion of coal is used to convert water into steam and then steam is used to rotate the turbine the rotation of turbine drives an a.c. generator, thereby producing a.c. power. The entire thermal power project needs continuous supply of water and thus they are built near Betwa River. A dam has been constructed for this purpose of collection of water, by the name of parichadam. Coal is also required for this project and it is supplied from mines of BCCL, ECL. At present, four units of Parichha are generating 640 mw of electricity. Uttar Pradesh Rajya Vidyut Utpadan Nigam Ltd. was constituted on 25 August 1980 under the companys act 1956 for construction of new thermal power projects in the state sector. On 14th Jan 2000, in accordance to up state electricity reforms acts 1999, UP state electricity board, till then responsible for generation, transmission and distribution of power within the state of Uttar Pradesh, was unbundled and operations of the state sector thermal power stations was handed over to UPRVUNL. 2 8. Products and Specifications Following two are the main products in a thermal power plant:- 1) Electricity Electricity is produced at approximately 15.5 KV after which it is stepped up to 220 KV for reduction in losses due to transmission. Then it is connected to the grid for supply. The main client for purchasing electricity of UPRVUNL is UPPCL which is UTTAR PRADESH POWER CORPORATION LIMITED. 2) Ash:- Ash is the byproduct of coal after its combustion. It can be categorized in two parts:- A) Fly ash, which is sold to cement manufacturing organizations like Diamond and Satna. Earlier they were given away to the same, but since posses certain value; theyre now being sold to them which generates revenues up to twenty lakhs. B) Ash slurry, it is a waste product which is generally provided to construction companies for road-filling etc. 3 9. Product Flow Chart Procedure for production of electricity is based on modified Rankine cycle. The four process of Rankine cycle as used in thermal power plants are as follows:- 1) Heat addition in boiler. 2) Adiabatic expansion in turbines. 3) Heat rejection in condenser and, 4) Adiabatic compression in boiler feed pumps. This may seem to be a simple enough process, but every step employs various circuits to accomplish the required conditions for the fore told steps. Certain circuits are as follows, Fuel and Ash Circuit. Air and Gas Circuit. Feed water and Steam Circuit. Cooling Water Circuit. Various methods are employed to increase the efficiency of classical rankine cycle by adding devices like air-preheater, economizer, superheater etc. 4 10. 5 11. Above is the flow chart of production of electricity in a thermal power plant. The input at boiler is the DM water and pulverized coal with air. The DM water is prepared in the water treatment plant facility where it is deionized and deareated. It prepared in the scale of neutral liquid i.e. 7ph, although, slightly basic nature is used. The coal is prepared at coal handling plant, where it first arrives in wagons. The coal is taken out from wagons with the help of a machine known as wagon tippler. The coal is the picked and sent to crushers, where it crushed and then to bunkers. From bunkers the coal moves on to mills and is finely grounded to a pulverized form and the fed to the boiler. Then this coal is fed to the boiler and combustion takes place. The energy of the combustion is helpful in transforming the water into the steam. This steam is then used to drive the turbine; the turbine shaft drives the generator. Hence electricity is developed. The other product, which is ash, is fed into the ash treatment plant and flue gasses are expelled in the atmosphere. 6 12. Chronological training diary 7th May 2014 to 13th May 2014 This week was dedicated to familiarization with power plant, a basic understanding was developed of the flow of various elements in the production cycle, like flow of steam, DM water, clarified cooling water, coal and flue gases. 14th May 2014 to 20th May 2014 This week was dedicated in the study of installed 210 MW turbines. Various concepts regarding turbine were studied like axial shift, casing expansion, barring gear mechanism, synchronization of turbine during startup, etc. 21th May2014 to 27th May 2014 We spent this week with familiarization with coal handling plant, learning flow of coal in it and the methods and processes of converting large sized coal to a form of powder. 28th May2014 to 6th june 2014 This time was spent in understanding the importance and working of ash handling plant and water treatment plant. 7 13. Production process Diagram of a typical coal-fired thermal power station In a coal based power plant coal is transported from coal mines to the power plant by railway in wagons or in a merry-go-round system. Coal is unloaded from the wagons to a moving underground conveyor belt. This coal from the mines is of no uniform size. So it is taken to the Crusher house and crushed to a size of 25mm. From the crusher house the coal is either stored in dead storage ( generally 20 days coal supply) which serves as coal supply in case of coal supply bottleneck or to the live storage(8 hours coal supply) in the raw coal bunker in the boiler house. Raw coal from the raw coal bunker is supplied to the Coal Mills by a Raw Coal Feeder. The Coal Mills or pulverizer pulverizes the coal to 200 mesh size. The powdered coal from the coal mills is carried to the boiler in coal pipes by high pressure hot air. The pulverized coal air mixture is burnt in the boiler in the combustion zone. Generally in modern boilers tangential firing system is used i.e. the coal nozzles/ guns formatngent to a circle. The temperature in fire ball is of the order of 1300 deg.C. The boiler is a water tube boiler hanging from the top. Water is converted to steam in the boiler and steam is separated from water in the boiler Drum. The saturated steam from the boiler drum is taken to the Low Temperature Superheater, Platen Superheater and Final Superheater respectively for superheating. 8 14. The superheated steam from the final superheater is taken to the High Pressure Steam Turbine. (HPT). In the HPT the steam pressure is utilized to rotate the turbine and the resultant is rotational energy. From the HPT the out coming steam is taken to the Reheater in the boiler to increase its temperature as the steam becomes wet at the HPT outlet. After reheating this steam is taken to the Intermediate Pressure Turbine (IPT) and then to the Low Pressure Turbine (LPT). The outlet of the LPT is sent to the condenser for condensing back to water by a cooling water system. This condensed water is collected in the hot well and is again sent to the boiler in a closed cycle. The rotational energy imparted to the turbine by high pressure steam is converted to electrical energy in the Generator. Principal Coal based thermal power plant works on the principal of Modified Rankine Cycle. 9 15. ComponentsofCoalFiredThermalPowerStation: Fuelpreparationsystem In coal-fired power stations, the raw feed coal from the coal storage area is first crushed into small pieces and then conveyed to the coal feed hoppers at the boilers. The coal is next pulverized into a very fine powder. The pulverizers may be ball mills, rotating drum grinders, or other types of grinders. Airpath External fans are provided to give sufficient air for combustion. The forced draft fan takes air from the atmosphere and, first warming it in the air preheater for better combustion, injects it via the air nozzles on the furnace wall. The induced draft fan assists the FD fan by drawing out combustible gases from the furnace, maintaining a slightly negative pressure in the furnace to avoid backfiring through any opening. Boilerfurnaceandsteamdrum Once water inside the boiler or steam generator, the process of adding the latent heat of vaporization or enthalpy is underway. The boiler transfers energy to the water by the chemical reaction of burning some type of fuel. The water enters the boiler through a section in the convection pass called the economizer. From the economizer it passes to the steam drum. Once the water enters the steam drum it goes down the down comers to the lower inlet water wall headers. From the inlet headers the water rises through the water walls and is eventually turned into steam due to the heat being generated by the burners located on the front and rear water walls (typically). As the water is turned into steam/vapor in the water walls, the steam/vapor once again enters the steam drum. The steam/vapor is passed through a series of steam and water separators and then dryers inside the steam drum. The steam separators and dryers remove water droplets from the steam and the cycle through the water walls is repeated. This process is known as natural circulation. The boiler furnace auxiliary equipment includes coal feed nozzles and igniter guns, soot blowers, water lancing and observation ports (in the furnace walls) for observation of the furnace interior. Furnace explosions due to any accumulation of combustible gases after a trip-out are avoided by flushing out such gases from the combustion zone before igniting the coal. The steam drum (as well as the superheater coils and headers) have air vents and drains needed for initial startup. The steam drum has internal devices that removes moisture from the wet steam entering the drum from the steam generating tubes. The dry steam then flows into the superheater coils. 10 16. Superheater Coal based power plants can have a superheater and/or reheater section in the steam generating furnace. Nuclear-powered steam plants do not have such sections but produce steam at essentially saturated conditions. In a coal based plant, after the steam is conditioned by the drying equipment inside the steam drum, it is piped from the upper drum area into tubes inside an area of the furnace known as the superheater, which has an elaborate set up of tubing where the steam vapor picks up more energy from hot flue gases outside the tubing and its temperature is now superheated above the saturation temperature. The superheated steam is then piped through the main steam lines to the valves before the high pressure turbine. Reheater Power plant furnaces may have a reheater section containing tubes heated by hot flue gases outside the tubes. Exhaust steam from the high pressure turbine is rerouted to go inside the reheater tubes to pickup more energy to go drive intermediate or lower pressure turbines. This is what is called as thermal power. Flyashcollection Fly ash is captured and removed from the flue gas by electrostatic precipitators or fabric bag filters (or sometimes both) located at the outlet of the furnace and before the induced draft fan. The fly ash is periodically removed from the collection hoppers below the precipitators or bag filters. Generally, the fly ash is pneumatically transported to storage silos for subsequent transport by trucks or railroad cars. Bottomashcollectionanddisposal At the bottom of the furnace, there is a hopper for collection of bottom ash. This hopper is always filled with water to quench the ash and clinkers falling down from the furnace. Some arrangement is included to crush the clinkers and for conveying the crushed clinkers and bottom ash to a storage site. Boilermake-upwatertreatmentplantandstorage Since there is continuous withdrawal of steam and continuous return of condensate to the boiler, losses due to blow down and leakages have to be made up to maintain a desired water level in the boiler steam drum. For this, continuous make-up water is added to the boiler water system. 11 17. Impurities in the raw water input to the plant generally consist of calcium and magnesium salts which impart hardness to the water. Hardness in the make-up water to the boiler will form deposits on the tube water surfaces which will lead to overheating and failure of the tubes. Thus, the salts have to be removed from the water, and that is done by a water demineralising treatment plant (DM). A DM plant generally consists of cation, anion, and mixed bed exchangers. Any ions in the final water from this process consist essentially of hydrogen ions and hydroxide ions, which recombine to form pure water. Very pure DM water becomes highly corrosive once it absorbs oxygen from the atmosphere because of its very high affinity for oxygen. The capacity of the DM plant is dictated by the type and quantity of salts in the raw water input. However, some storage is essential as the DM plant may be down for maintenance. For this purpose, a storage tank is installed from which DM water is continuously withdrawn for boiler make-up. The storage tank for DM water is made from materials not affected by corrosive water, such as PVC. The piping and valves are generally of stainless steel. Sometimes, a steam blanketing arrangement or stainless steel doughnut float is provided on top of the water in the tank to avoid contact with air. DM water make-up is generally added at the steam space of the surface condenser (i.e., the vacuum side). This arrangement not only sprays the water but also DM water gets de aerated, with the dissolved gases being removed by an air ejector attached to the condenser. Steamturbine-drivenelectricgenerator Rotor of a modern steam turbine, used in a power station 12 18. The steam turbine-driven generators have auxiliary systems enabling them to work satisfactorily and safely. The steam turbine generator being rotating equipment generally has a heavy, large diameter shaft. The shaft therefore requires not only supports but also has to be kept in position while running. To minimize the frictional resistance to the rotation, the shaft has a number of bearings. The bearing shells, in which the shaft rotates, are lined with a low friction material like Babbitt metal. Oil lubrication is provided to further reduce the friction between shaft and bearing surface and to limit the heat generated. Barringgear Barring gear (or turning gear) is the mechanism provided to rotate the turbine generator shaft at a very low speed after unit stoppages. Once the unit is tripped (i.e., the steam inlet valve is closed), the turbine coasts down towards standstill. When it stops completely, there is a tendency for the turbine shaft to deflect or bend if allowed to remain in one position too long. This is because the heat inside the turbine casing tends to concentrate in the top half of the casing, making the top half portion of the shaft hotter than the bottom half. The shaft therefore could warp or bend by millionths of inches. This small shaft deflection, only detectable by eccentricity meters, would be enough to cause damaging vibrations to the entire steam turbine generator unit when it is restarted. The shaft is therefore automatically turned at low speed (about one percent rated speed) by the barring gear until it has cooled sufficiently to permit a complete stop. Condenser Diagram of a typical water-cooled surface condenser 13 19. The surface condenser is a shell and tube heat exchanger in which cooling water is circulated through the tubes. The exhaust steam from the low pressure turbine enters the shell where it is cooled and converted to condensate (water) by flowing over the tubes as shown in the adjacent diagram. Such condensers use steam ejectors or rotary motor-driven exhausters for continuous removal of air and gases from the steam side to maintain vacuum. For best efficiency, the temperature in the condenser must be kept as low as practical in order to achieve the lowest possible pressure in the condensing steam. Since the condenser temperature can almost always be kept significantly below 100 C where the vapor pressure of water is much less than atmospheric pressure, the condenser generally works under vacuum. Thus leaks of non- condensible air into the closed loop must be prevented. Plants operating in hot climates may have to reduce output if their source of condenser cooling water becomes warmer; unfortunately this usually coincides with periods of high electrical demand for air conditioning. The condenser generally uses either circulating cooling water from a cooling tower to reject waste heat to the atmosphere, or once-through water from a river, lake or ocean. Feedwaterheater In the case of a conventional steam-electric power plant utilizing a drum boiler, the surface condenser removes the latent heat of vaporization from the steam as it changes states from vapour to liquid. The heat content (joules or Btu) in the steam is referred to as enthalpy. The condensate pump then pumps the condensate water through a Air ejector condenser and Gland steam exhauster condenser. From there the condensate goes to the deareator where the condenstae system ends and the Feed water system begins. Preheating the feed water reduces the irreversibilitys involved in steam generation and therefore improves the thermodynamic efficiency of the system. This reduces plant operating costs and also helps to avoid thermal shock to the boiler metal when the feed water is introduced back into the steam cycle. Deaerator A steam generating boiler requires that the boiler feed water should be devoid of air and other dissolved gases, particularly corrosive ones, in order to avoid corrosion of the metal. Generally, power stations use a deaerator to provide for the removal of air and other dissolved gases from the boiler feedwater. A deaerator typically includes a vertical, domed aeration section mounted on top of a horizontal cylindrical vessel which serves as the deaerated boiler feedwater storage tank. 14 20. Coolingtower A cooling tower is a heat rejection device, which extracts waste heat to the atmosphere though the cooling of a water stream to a lower temperature. The type of heat rejection in a cooling tower is termed evaporative in that it allows a small portion of the water being cooled to evaporate into a moving air stream to provide significant cooling to the rest of that water stream. The heat from the water stream transferred to the air stream raises the airs temperature and its relative humidity to 100%, and this air is discharged to the atmosphere. Evaporative heat rejection devices such as cooling towers are commonly used to provide significantly lower water temperatures than achievable with air cooled or dry heat rejection devices, like the radiator in a car, thereby achieving more cost-effective and energy efficient operation of systems in need of cooling. Thecoolingtowersareoftwotypes:- 1. Natural Draft Cooling Tower 2. Mechanized Draft Cooling Tower i. Forced Draft cooling tower ii. Induced Draft cooling tower iii. Balanced Draft cooling tower 15 21. Auxiliarysystems Oil system An auxiliary oil system pump is used to supply oil at the start-up of the steam turbine generator. It supplies the hydraulic oil system required for steam turbines main inlet steam stop valve, the governing control valves, the bearing and seal oil systems, the relevant hydraulic relays and other mechanisms. At a preset speed of the turbine during start-ups, a pump driven by the turbine main shaft takes over the functions of the auxiliary system. Generatorheatdissipation The electricity generator requires cooling to dissipate the heat that it generates. While small units may be cooled by air drawn through filters at the inlet, larger units generally require special cooling arrangements. Hydrogen gas cooling, in an oil-sealed casing, is used because it has the highest known heat transfer coefficient of any gas and for its low viscosity which reduces windage losses. This system requires special handling during start-up, with air in the chamber first displaced by carbon dioxide before filling with hydrogen. This ensures that the highly flammable hydrogen does not mix with oxygen in the air. The hydrogen pressure inside the casing is maintained slightly higher than atmospheric pressure to avoid outside air ingress. The hydrogen must be sealed against outward leakage where the shaft emerges from the casing. Mechanical seals around the shaft are installed with a very small annular gap to avoid rubbing between the shaft and the seals. Seal oil is used to prevent the hydrogen gas leakage to atmosphere. The generator also uses water cooling. Since the generator coils are at a potential of about 22 kV and water is conductive, an insulating barrier such as Teflon is used to interconnect the water line and the generator high voltage windings. De mineralized water of low conductivity is used. Generatorhighvoltage system The generator voltage ranges from 11 kV in smaller units to 22 kV in larger units. The generator high voltage leads are normally large aluminum channels because of their high current as compared to the cables used in smaller machines. They are enclosed in well- grounded aluminum bus ducts and are supported on suitable insulators. The generator high voltage channels are connected to step-up transformers for connecting to a high voltage electrical substation (of the order of 115 kV to 520 kV) for further transmission by the local power grid. The necessary protection and metering devices are included for the high voltage leads. Thus, the steam turbine generator and the transformer form one unit. In smaller units, generating at 11 kV, a breaker is provided to connect it to a common 11 kV bus system. 16 22. Othersystems Monitoringandalarmsystem Most of the power plant operational controls are automatic. However, at times, manual intervention may be required. Thus, the plant is provided with monitors and alarm systems that alert the plant operators when certain operating parameters are seriously deviating from their normal range. Batterysuppliedemergencylightingandcommunication A central battery system consisting of lead acid cell units is provided to supply emergency electric power, when needed, to essential items such as the power plants control systems, communication systems, turbine lube oil pumps, and emergency lighting. This is essential for a safe, damage-free shutdown of the units in an emergency situation. 17 23. TURBINES A steamturbine is a mechanical device that extracts thermal energy from pressurized steam, converts it into rotary motion. Its modern manifestation was invented by sir Charles 1884. It has almost completely replace greater thermal efficiency and hi rotary motion, it is particularly suited all electricity generation in the worl TYPES Schematic operation of a steam turbine generator system l device that extracts thermal energy from pressurized steam, n. Its modern manifestation was invented by sir Charles almost completely replaced the reciprocating piston steam engine primarily because of it greater thermal efficiency and higher power-to-weight ratio. Because the turbine generates motion, it is particularly suited to be used to drive an electrical generator electricity generation in the world is by use of steam turbines. Schematic operation of a steam turbine generator system l device that extracts thermal energy from pressurized steam, and n. Its modern manifestation was invented by sir Charles Parsons in d the reciprocating piston steam engine primarily because of it weight ratio. Because the turbine generates enerator-about 80% of 18 24. Steam turbines are made in a variety o f sizes ranging from small