Slide 1: Seminar submitted by:- Nikhil Shrimali Electrical Engineering 4 th year INTRODUCTION : Kota Thermal Power Station is Rajasthan's First major coal power station. Presently it is in operation with installed capacity of 1240MW.And one more unit of 250MW is slated for commissioning in March 2009. INTRODUCTION Stage Unit No. Capacity(MW) Synchronizing Date Cost(Rs. Crore) I 1 110 17.1.1983 143 2 110 13.7.1983 II 3 210 25.9.1988 480 4 210 1.5.1989 III 5 210 26.3.1994 480 IV 6 195MW 31.7.2003 635 V 7 195MW 30.5 2009 880 Excellent Performance: Kota Thermal Power Station of RVUN is reckoned one of the best, efficient and prestigious power station of the country. KTPS has established a record of excellence and has earned meritorious productivity awards from the Ministry of Power, Govt. of India during 1984,1987,1989,1991& every year since 1992-93 onwards. Excellent Performance Year Million Units Generated Plant Load factor(%) Award 1999-00 6314 84.44 Cash award of Rs.8.31.Lacs for productivity and Rs.6.19.Lacs each for saving in specific oil consumption for the years 1999 and 2000, Shields and Bronze medal. 2000-01 6437 86.60 Golden Shield award from Union Ministry of power 2001-02 6351 85.30 2002-03 6553 88.01 2003-04 6424 86.04 Definition Of Thermal Power Station: 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 either drives an electrical generator or does some other work, like ship propulsion . 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 electrical energy. Definition Of Thermal Power Station Operations In Thermal Power Station :
Step wise operations in a
thermal power plant
are as follows:- Coal is used as a fuel to boil the water. Water is boiled to form pressurized steam. Pressurized steam is the force that cause the turbine to rotate at a very high speed. Low pressure steam after pushing through the turbine ,it’s going into the condenser. Condenser – the place where the steam is condensed back it it’s liquid form .Then the process is repeated. Operations In Thermal Power Station
Main Parts Of Thermal Power station: 1. Cooling tower 9. Steam Control valve 17. Forced,induced draught (draft) fan 2. Cooling water pump 10. Deaerator 18. Reheater 3. Transmission line ( 3-phase ) 11. Feedwater heater 19. Combustion air intake 4. Step-up transformer ( 3-phase ) 12. Coal hopper 20. Economiser 5. Electrical generator ( 3-phase ) 13. Coal pulverizer 21. Air preheater 6. Low,intermediate,high pressure steam turbine 14. Boiler & steam drum 22. Precipitator 7. Condensate pump 15. Bottom ash hopper 23. Flue gas stack 8. Surface condenser 16. superheater Main Parts Of Thermal Power station COAL HANDLING PLANT: COAL HANDLING PLANT RAW MATERIAL HOPPER unload WAGON TRIPPLER CRUSHER HOUSE Conveyer belt Coal size reduced By 20mm BUNKER Conveyer belt FURNACE Wagon Trippler: Wagon Trippler Rated Output. : 71 KW. Rated Voltage. : 415 V. Rated Current. : 14.22 Amp. Rated Speed. : 975 rpm. No. of phases. : 3 Frequency. : 50 HZ. Conveyor Belt: Conveyor Belt Conveyor belt Specification of Stacker / Reclaimer :- Belt width : 1400 mm. Speed : 2.2 m/second. Schedule of motor : All 3-phas induction motors Bucket wheel motor : 90 KW. Boom Conveyor motor : 70 KW. Intermediate Conveyor Motor : 90 KW Boom Housing Motor : 22KW. Slewing assembly : 10 KW. Travel Motor : 7.5 KW. Vibrating Feeder : 2x6 KW. Total installed power. : 360 KW. Conveyor Specification:- Capacity : 1) 1350 tonne per hour 2) 750 tonne per hour. No. of conveyor : 38 Horizontal length : 28 meters Lift(M) (approx.) : Variable to suit the system. Belt width : 1400 mm. specification of conveyor motor Metal Part Seperator: Metal Part Seperator CRUSHER: CRUSHER It consists of crushers which are used to crush the coal to 20 mm. size. There are mainly two type of crushers working in KSTPS:- Primary Crushers i . e. i ) Rail crushers or ii) Rotary breaker. Secondary Crushers i . e . Ring granulators. Type : 80" 5 A breakers. Capacity : 1350 TPH Rates/ 1500 TPH Design. Feed material : Rom Coal. Feed size : (-) 1200 mm. (approx.) End Product size : (-) 500 mm Motor rating : 2 Nos. 125 KW, 100 rpm Crushers : 225. BUNKERS: BUNKERS COAL MILL / COAL MILL INSIDE VIEW: COAL MILL / COAL MILL INSIDE VIEW COAL MILL COAL MILL INSIDE VIEW ASH HANDLING PLANT : ASH HANDLING PLANT This plant can be divided into 3 sub plants as follows:- 1) Fuel and Ash Plant. 2) Air and Gas Plant. 3) Ash Disposal and & Dust Collection plant. Fuel and ash plant : Fuel and ash plant Coal is used as combustion material in KTPS, In order to get an efficient utilization of coal mills. The Pulverization also increases the overall efficiency and flexibility of boilers. However for light up and with stand static load, oil burners are also used. Ash produced as the result of combustion of coal is connected and removed by ash handling plant. Ash Handling Plant at KTPS consists of specially designed bottom ash and fly ash in electro static precipitator economizer and air pre-heaters hoppers. Air & Gas Plant : Air & Gas Plant Air from atmosphere is supplied to combustion chamber of boiler through the action of forced draft fan. In KTPS there are two FD fans and three ID fans available for draft system per unit. The air before being supplied to the boiler passes through pre-heater where the flue gases heat it. The pre heating of primary air causes improved and intensified combustion of coal. The flue gases formed due to combustion of coal first passes round the boiler tubes and then it passes through the super heater and then through economizer in re-heater the temperature of the steam (CRH) coming from the HP turbines heated with increasing the number of steps of re-heater the efficiency of cycle also increases. In economizer the heat of flue gases raises the temperature of feed water. Finally the flue gases after passing through the Electro-Static Precipitator is exhausted through chimney. Ash Disposal & Dust Collection Plant: Ash Disposal & Dust Collection Plant KSTPS has dry bottom furnace. Ash Handling Plant consists of especially designed bottom and fly ash system for two path boiler. Two slurry pumps are provided which is common to both units & used to make slurry and further transportation to ash dyke through pipe line. Dry free fly ash is collected in two number of 31 fly ash hoppers which are handled by two independent fly ash system. The ash is removed from fly ash hoppers in dry state is carried to the collecting equipment where it is mixed with water and resulting slurry sump is discharged Utilization Of Ash: Utilization Of Ash 1. Manufacturing of building materials. 2. Making of concrete. 3. Manufacturing of pozzuolana cement. 4. Road construction etc. ELECTRO-STATIC PRECIPTATOR : ELECTRO-STATIC PRECIPTATOR For general mankind, today an Eco friendly industry is must. As far as air pollution is concerned now a day various flue gases filter are there in service. The choice depends on the size of suspended particle matter. These filters are E.S.P. Fabric filter high efficiency cyclone separations and stalling room. Fop fly ash, where the particle size vary from 0.75 microns to 100 micron use gradually use E.S.P. to purify the flue gases due to its higher efficiency & low running cost etc. In an ESP the dust lidder gas is passed through an intense electric field, which causes ionization of the gases& they changed into ion while travelling towards opposite charged electrode get deposited as particles and thus dust is electric deposited an electrode creating the field. It is continuous process. CONTROLLER: CONTROLLER Now a day micro-processor based intelligent controllers are used to regulate the power fed to the HVR. The controls the firing / ignition angle of the thyristor connected in parallel mode. Input out waves of the controller and HVR are also shown above, which clearly indicates that average power fed to ESP field can be controlled by variation of the firing angle of thyristor. The output of controller with respect to time is also controlled by microprocessor, so that ESP operation is smooth and efficient. The chars is as shown: As can be seen in the event of spark between electrodes the output of controller is reduced to zero for few millisecond for quenching the spark. Controller also takes place care of fault in KVR and gives a trapping and non-trapping alarm as per the nature of fault. BOILER: BOILER A boiler (or steam generator) is a closed vessel in which water, under pressure is converted into steam. It is one of the major components of a thermal power plant. A boiler is always designed to absorb maximum amount of heat released in process of combustion. This is transferred to the boiler by all the three modes of heat transfer i.e. conduction. Convection and radiation. Boilers are classified as: Boilers are classified as Fire tube boiler Water tube boiler BOILERS ARE TWO TYPES:- Fire tube boiler:- In this type the products of combustion pass through the tubes which are surrounded by water. These are economical for low pressure only. Water tube boiler:- In this type of boiler water flows inside the tubes and hot gases flow outside the tubes. These tubes are interconnected to common water channels and to steam outlet. The water tube boilers have many advantages over the fire tube boilers High evaporation capacity due to availability of large heating surface. Better heat transfer to the mass of water. Better efficiency of plant owing to rapid and uniform circulation of water in tubes. Better overall control. Easy removal of scale from inside the tubes . Furnace: Furnace Furnace is primary part of the boiler where the chemical energy available in the fuel is converted into thermal energy by combustion. Furnace is designed for efficient and complete combustion. Major factors that assist for efficient combustion are the temperature inside the furnace and turbulence, which causes rapid mixing of fuel and air. In modern boilers, water-cooled furnaces are used. PULVERISED FUEL SYSTEM: PULVERISED FUEL SYSTEM The boiler fuel firing system is tangentially firing system in which the fuel is introduced from wind nozzle located in the four corners inside the boiler The crushed coal from the coal crusher is transferred into the unit coalbunkers where the coal is stored for feeding into pulverizing mill through rotary feeder the rotary feeders feed the coal to pulverize mill at a definite rate. Then coal burners are employed to fire the pulverized coal along with primary air into furnace. Fuel Oil System The functional requirement of the fuel burning system is to supply a controllable and uninterrupted flammable furnace input of fuel and air and to continuously ignite and burn the fuel as rapidly as it is introduced into the furnace ECONOMIZER: ECONOMIZER The flue gases coming out of the boiler carry lot of heat. An economiser extracts apart of this heat from the flue gases and uses it for heating the feed water before it enters into the steam drum. The use of economiser results in saving fuel consumption and higher boiler efficiency but needs extra investment. AIR PREHEATERS Air preheaters are employed to recover the heat from the flue gases leaving the economiser and are used to heat the incoming air for combustion. Cooling of flue gases by 20% raises the plant efficiency by l%. SUPER HEATER: SUPER HEATER Superheated steam is that steam, which contains more heat than the saturated steam at the same pressure i.e. it, has been heated above the temperature corresponding to its pressure. A superheater is a device which removes the last traces of moisture from the saturated steam leaving the boiler tubes and also increases its temperature above the saturation temperature. Reheater Reheaters are provided to raise the temperature of the steam from which part of energy has already been extracted by HP turbine. FUEL: FUEL COAL:- Type Quantity consumed Type of handing. Ash disposal : Slack Coal : 3074 tones per day : Conveyor : Wet system HSD and fuel oil a) HSD - 5520 KL per Year b) Furnace Oil: 28800 KL per Year 1/2. 180 Meters 198 M3/ Sec. Air emitted. 140’c One for each unit OIL:- Type : Quantity : No. of chimney/ stack : Height of Chimney : Volume of flue Gas : Temp. of flue gas : ESP : STEAM TURBINE : STEAM TURBINE Turbine is a machine in which a shaft is rotated steadily by impact or reaction of current or stream of working substance (steam, air, water, gases etc) upon blades of a wheel Working of the steam turbine depends wholly upon the dynamic action of Steam. The steam is caused to fall in pressure in a passage of nozzle doe to this fall in pressure a certain amount of heat energy is converted in to mechanical kinetic energy and the steam is set moving with a greater velocity. The main technical data of 110 MW turbines is given below: The main technical data of 110 MW turbines is given below Rated output 110 MW. Economic output 95 MW. Rated speed 3000 rpm Direction of rotation viewing from the front bearing pedestal clock wise Rated steam pressure before stop valve 130 ata Maximum steam pressure before stop valve 146 ata Rated temperature of steam before the stop valve. 535°C Maximum temperature of steam before the stop valve. 545°C Rated pressure of steam 31.6 ata Description of Steam Turbines: Description of Steam Turbines Steam flow HP Turbine IP Turbine LP Turbine STEAM FLOW:- 210 MW steam turbine is a tandem compound machine with HP, IP & LP parts. The HP part is single flow cylinder and HP & LP parts are double flow cylinders. The individual turbine rotors and generator rotor are rigidly coupled. HP TURBINE:- The HP casing is a barrel type casing without axial joint. Because of its rotation symmetry the barrel type casing remain constant in shape and leak proof during quick change in temperature. The HP turbine consists of 25 reaction stages. Slide 31: IP TURBINE:- The IP turbine consists of 20 reaction stages per flow. The moving and stationary blades are inserted in appropriately shaped grooves in shaft and inner casing. The IP part of turbine is of double flow construction. The casing of IP turbine is split horizontally and is of double shell construction. The double flow inner casing is supported kinematically in the outer casing. The steam from IIP turbine after reheating enters the inner casing from above and below through two inlet nozzles. LP TURBINE:- The casing of double flow type LP turbine is of three shell design. The shells are axially split and have rigidly welded construction. The outer casing consist of the front and rear walls, the lateral longitudinal support bearing and upper part Steam admitted to LP turbine from IP turbine flows into the inner casing from both sides through steam inlet nozzles. ELEGTRICITY GENERATOR : ELEGTRICITY GENERATOR Thermal power station burns the fuel and use the resultant heat to raise the steam which drives the turbo-generator. The fuel may be "Fossil" (Coal, Oil and Natural Gas) whichever fuel is used the object is same to convert the heat into mechanical energy to electrical energy by rotating a magnet inside the set of winding. TURBO GENERATOR:- TURBO GENERATOR manufactured by B.H.E.L . The generator stator is a tight construction, supporting & enclosing the stator windings, core and hydrogen coolers. The generator is driven by directly coupled steam turbine at a speed of 3000 r.p.m. MAIN PARTS OF GENERATOR: MAIN PARTS OF GENERATOR STATOR ROTOR STATOR:- The stator frame of welded steel frame construction, which gives sufficient & necessary rigidity to minimize the vibrations and to withstand the thermal gas pressure. The complete frame is subjected to hydraulic test at a pressure of 7 ATA . Stator bars are manufactured as half bars. Each stator half coil is composed of double glass cover and bars of copper transposed in straight portion of "Robill Method" so that each strip occupies every radial portion in the bar. For an equal length along the bar. Six output leads (3 1ong, 3 short) have been brought out of the coming on the exciter side. External connections are to be made to the three shorter terminals, which are phase terminals. Slide 34: Generator bearings have electrical seats of consists of steel bodies with removable steel pads. The bearings are formed for forced lubrication of oil at a pressure of 2 - 3 ATM / from the same pump that supplies oils to the turbine, bearings & governing gears. The machine is designed with ventilation system having 2 ATM rated hydrogen pressure. Two axial fans mounted on either side of the rotor to ensure circulation of hydrogen. . The Clearing of the individual cooler element can be carried out from both ends of the Generator even during operation. Three Hydrogen Coolers each comprising of two individual units are mounted inside the stator frame. The inlet and outlet of cooling water from both of machine i.e. from non-driving side as well as turbine side Slide 35: ROTOR:- Rotor shaft consists of single piece alloy steel forging of high mechanical and magnetic properties rotor is dynamically balanced and subject to 120 % over speed test at the work balancing tunnel so as to ensure reliable operation Rotor winding is of direct coil type and consists of parallel strips of very high conductivity Silver Bearing Copper, bent on edge to form coil. The coils are placed in impregnated glass, laminated short shells; using glass strips inter turn insulation and will be brazed at the end to form continuous winding. The complete winging will be packed at high temperature and pressed to size by heavy steel damping rings. TECHNICAL DATA: TECHNICAL DATA Generator (110 M W):- Type Continuous apparent power Active power Power factor Rated voltage Current Critical speed Frequency Phase connection No. of terminals Main diameter of slip rings Voltage regulation Reactance : t.g.p.2, 34, 602 : 1, 37, 50K0V A. : 7, 10, 000KW. : 0.8 (lagging). : 1000+ 5%rated. : 7,220 A : 3000 r.p.m.at : 50 Hz. : Double star. : 6. : 420 mm. : 39 %. : Informative COOLING SYSTEM: COOLING SYSTEM In KSTPS hydrogen cooling system is employed for generator cooling. Hydrogen is used for cooling medium primarily because of its superior cooling properties & low density. Thermal conductivity of hydrogen 7.3 times of air. It also has higher transfer co-efficient. Its ability to transfer heat through forced convection is about 75% better than air. Cooling Tower : Common applications include cooling the circulating water used in oil refineries , chemical plants , power stations and building cooling Cooling towers are heat removal devices used to transfer process waste heat to the atmosphere . Cooling towers may either use the evaporation of water to remove process heat and cool the working fluid to near the wet-bulb air temperature or rely solely on air to cool the working fluid to near the dry-bulb air temperature . Cooling Tower EXCITATION SYSTEM: EXCITATION SYSTEM The electric power Generators requires direct current excited magnets for its field system. The excitation system must be reliable, stable in operation and must response quickly to excitation current requirements. WATER TREATTENT PLANT : WATER TREATTENT PLANT The principle problem in high pressure boiler is to control corrosion and steam quality. Slide 41: The impurities present in water are as follows:- 1) Un-dissolved and suspended solid materials. 2) Dissolved slats and minerals. 3) Dissolved gases. 4) Other minerals (oil, acid etc.). 5). a) Turbidity & Sediment. b) Silica. c) Micro Biological. d) Sodium& Potassium Salt. e) Dissolved Sales Minerals. 6). a) O2gas. b) CO2 gas. CIRCULAR TANK SWITCH YARD: SWITCH YARD Two 220 KV bus bars have been provided in switch yard and are inter-connected through a bus coupler. . Each station transformer has two windings one secondary side and is rated for 50/25/25mva, 270/7/7.2 kva four feeder take off from 220 switch yard two to SKATPURA GSS and other to HEERAPURA , Jaipur GSS. Each of four feeder are provided with bypass isolators which is connected across line breaker and breaker isolator. SALIENT FEATURE OF K.S.T.P.S.: SALIENT FEATURE OF K.S.T.P.S. LOCATION-: Sakatpura, Kota. CAPACITY-: A) 1 st Stage-: 2x110 MW . B) 2 nd Stage-: 2x210 MW. C) 3 rd Stage-: 1x210 MW. D) 4 th Stage-: 1x195 MW. E) 5 th Stage-: 1x195 MW (commissioned in September 2008). SOURCE OF WATER- : Chambal River. BOILER-: a) Type. Tangentially fired natural, circulation, balanced raft, direct fired radiant reheat, water tube boiler. b) No. of units . 7 c) Max. Efficiency. BHEL (86.6+ 1) % d) Capacity. 375 tonnes 1 Hr. e) Steam Pressure 139 Kg./cm² f) Steam Temp. 540 c Slide 44: QUERIES ?