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A project report on adani power ltd.
A project report on adani power ltd.
A project report on adani power ltd.
A project report on adani power ltd.
A project report on adani power ltd.
A project report on adani power ltd.
A project report on adani power ltd.
A project report on adani power ltd.
A project report on adani power ltd.
A project report on adani power ltd.
A project report on adani power ltd.
A project report on adani power ltd.
A project report on adani power ltd.
A project report on adani power ltd.
A project report on adani power ltd.
A project report on adani power ltd.
A project report on adani power ltd.
A project report on adani power ltd.
A project report on adani power ltd.
A project report on adani power ltd.
A project report on adani power ltd.
A project report on adani power ltd.
A project report on adani power ltd.
A project report on adani power ltd.
A project report on adani power ltd.
A project report on adani power ltd.
A project report on adani power ltd.
A project report on adani power ltd.
A project report on adani power ltd.
A project report on adani power ltd.
A project report on adani power ltd.
A project report on adani power ltd.
A project report on adani power ltd.
A project report on adani power ltd.
A project report on adani power ltd.
A project report on adani power ltd.
A project report on adani power ltd.
A project report on adani power ltd.
A project report on adani power ltd.
A project report on adani power ltd.
A project report on adani power ltd.
A project report on adani power ltd.
A project report on adani power ltd.
A project report on adani power ltd.
A project report on adani power ltd.
A project report on adani power ltd.
A project report on adani power ltd.
A project report on adani power ltd.
A project report on adani power ltd.
A project report on adani power ltd.
A project report on adani power ltd.
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A project report on adani power ltd.

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A TRAINING REPORT ON THERMAL POWER PLANT

A TRAINING REPORT ON THERMAL POWER PLANT

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  • 1. 1 A Practical Training Report On ADANI POWER LIMITED Submitted in partial fulfillment for the award of the degree of BACHELOR OF TECHNOLOGY In Mechanical Engineering (13 May 2013- 13 June 2013) Submitted by :- Nipranch Shah 10ME001073 B.Tech VIIth sem SIR PADAMPAT SINGHANIA UNIVERSITY UDAIPUR(RAJ.)
  • 2. 2 TO WHOM IT MAY CONCERN I hereby certify that NIPRANCH SHAH roll no. 10ME001073 of Sir Padampat Singhania University undergone thirty days industrial training from 13th May 2013 to 13th June 2013 at our organization to fulfill the requirement for the award of degree of B.TECH Mechanical Engineering. During his tenure with us we found him sincere and hard working. We wish him a great success in the future. Signature of student Nipranch Shah
  • 3. 3 PREFACE A student gets theoretical knowledge from classroom and gets practical knowledge from industrial training. When these two aspects of theoretical knowledge and practical experience together then a student is full equipped to secure his best. In conducting the project study in an industry, students get exposed and have knowledge of real situation in the work field and gains experience from them. The object of the summer training cum project is to provide an opportunity to experience the practical aspect of Technology in any organization. It provides a chance to get the feel of the organization and its function. The fact that thermal energy is the major source of power generation itself shows the importance of thermal power generation in India – more than 60 percent of electric power is produced by steam plant in India. In steam power plants, the heat of combustion of fossil fuels is utilized by the boilers to raise steam at high pressure and temperature. The steam so produced is used in driving the steam turbine coupled to generators and thus in generating ELECTRICAL ENERGY
  • 4. 4 INTRODUCTION TO THE COMPANY ABOUT THE COMPANY Adani Power Limited is the power business arm of Indian business conglomerate Adani Group with head office at Ahmedabad, Gujarat. The company is India's largest thermal private power producer with capacity of 5280 MW and also it is the largest solar power producer of India with capacity 40MW. The company currently operates five supercritical boilers of 660MW each (as per March 2012) at Mundra Gujrat & One 660MW out of 05 units at Tirora, Maharashtra. It also operates a mega solar plant of 40MW at Surendra nagar, Gujrat. It is India's first company to achieve the supercritical technology. The plant is the only thermal power plant in india to be certified by UN under CDM. The company is currently implementing 16500 MW at different stages of construction. Its mission is to achieve 20000 MW by 2020. The company currently produces electricity using only coal. 100MW of solar power station is also under advanced stage of implementation at Surendranagar in Gujarat out of which 40MW is already commissioned. The company has gone to long term PPAs of about 7200MW of its 9280MW with government of Gujarat, Maharashtra, Haryana and Rajasthan
  • 5. 5 HISTORY The company was changed to Adani Power Private Limited. The RoC issued a fresh certificate of incorporation on 3 June 2002. The Company was, thereafter, converted into a public limited company on 12 April 2007 and the name of the Company was changed to Adani Power Limited. Further, upon ceasing to be a private limited company, the word private was deleted through a special resolution at the EGM of the Company held on 28 March 2007. The fresh certificate of incorporation consequent to change of the name was granted by the RoC to the Company on 12 April 2007. Adani power was started as a power trading company 1996. It started generation in July 2009 by implementation of its first 330MW of 4620mw at Mundra. The Mundra super mega project is the largest coal based power project of India and fifth largest in the world. The company commissioned another three 330 MW by November 2010 and country's 1st supercritical unit of 660 MW on 22 December 2010, making its capacity 1980 MW. 0n 6 June 2011 it synchronized its second unit of 660 MW bringing the total generating capacity to 2640 MW and on 2 October 2011, it synchronized its third super critical unit with national grid .With this,Adani power has become largest thermal power generating company in the private sector and the Mundra plant has become India's Largest Power plant with capacity 3300MW. In February 2012, it commissioned the last unit of Mundra Project to take its capacity to 4620MW which makes the Mundra TPP to be the largest privately held Thermal power plant of World and fifth largest on an overall basis(As per March,2012). OPERATIONS The company currently operates 4620 MW coal based Mundra Thermal Power Station at Mundra, Gujarat. It operates first power transmission project of 400KV Double Circuit Transmission System from the Mundra plant to Dehgam (430 km). The company operates India's first supercritical unit of 660MW. It also implemented country's only private 1000 km HVDC transmission line for efficient transmission of power to Haryana. The company produces 40MW of solar power in Gujrat showing its interest in renewable energy. The company is currently implementing thermal projects of 3300MW (5X660MW) at Tiroda, Maharastra at Tirora one unit of 660 MW have been generating Power since Mid of 2012 & another is going to commissioned in the end of 2012 and 1320MW (2X660MW) at Kawai, Rajsthan, and a 100 MW solar project at Surendranagar,Gujrat(40MW commissioned).
  • 6. 6 FUTURE PROJECTS As of January 2011, the company has 16500MW under implementation and planning stage. A few of them are 3300MW coal based TPP at Bhadreswar in Gujarat, 2640 MW TPP at Dahej in Gujarat, 1320 MW TPP at Chhindwara in Madhya Pradesh, 2000 MW TPP at Anugul in Orissa and 2000MW gas based power project at Mundra in Gujarat. The company is also bidding for 1000 MW of lignite coal based power plant at Kosovo showing its international projects.
  • 7. 7 1. INTRODUCTION TO THE POWER PLANT Electricity is the only form of energy which is easy to produce, easy to transport, easy to use and easy to control. So, it is mostly the terminal of energy for transmission and distribution. Electricity consumption per capita is the index of the living standard of people of place or country. Electricity Demand and Supply in India: India is facing energy shortages of 11% of demand and even higher peak shortages of 14%Demand-supply gap is more acute in Western region (where 70% of the Project’s power will be supplied) with energy deficit at 16% and peak deficit at 21% Capacity additions of 160,000 MW required in the next 10 years to meet India’s power demand. New capacity need to be added using a combination of coal, hydro, gas, nuclear and wind projects Types of Power Plants: Electricity in bulk quantities is produced in power plants, which can be of the following types:  Thermal  Nuclear  Hydraulic  Gas turbine  Geothermal India’s Installed Capacity (132,329 MW) 55% 10% 26% 3% 6% Coal & lignite Gas Hydro Nuclear Other
  • 8. 8 2. LOCATIONAL DETAILS OF MUDRA Site Location Latitude : 22º48’35”N Longitude : 69º32’53”E Nearest Village : Tunda, Taluka Mundra, Dist Kutch, Gujarat State. Mean Sea Level : 5.1 m Total area : 294 Ha Highway Connectivity State Highway : SH6 - 3.4 KM National Highway : NH 8A extension - 5.7 km Nearest port : Mundra Port – 17.23 km Airport Bhuj : 52 KM Kandla : 64 KM Adani Pvt. Port : 25 KM
  • 9. 9 3.OVERVIEW OF POWER PROJECT at MUNDRA Mundra Thermal Power Project Power Generation Capacity Adani Group’s foray into power sector – The Group’s foray into power sector is natural extension for Adani Group, which has emerged as India’s largest coal importer and second largest power entity in the country. Adani Power Ltd (APL) is setting up a 4620 MW power project at Mundra based on imported coal. The execution will be done in the following stages;  2*330 Phase I (sub critical)  2*330 Phase II (sub critical)  3*660 Phase III (super critical)  2*660 Phase IV (super critical)
  • 10. 10 4.A VIEW OF ADANI POWER LTD.
  • 11. 11 5.DIAGRAM OF A TYPICAL COAL-FIRED THERMAL POWER STATION 1. Cooling tower 10. Steam Control valve 19. Superheater 2. Cooling water pump 11. High pressure steam turbine 20. Forced draught (draft) fan 3. transmission line (3-phase) 12. Deaerator 21. Reheater 4. Step-up transformer (3-phase) 13. Feed water heater 22. Combustion air intake 5. Electrical generator (3-phase) 14. Coal conveyor 23. Economiser 6. Low pressure steam turbine 15. Coal hopper 24. Air preheater 7. Condensate pump 16. Coal pulveriser 25. Precipitator 8. Surface condenser 17. Boiler steam drum 26. Induced draught (draft) fan 9. Intermediate pressure steam turbine 18. Bottom ash hopper 27. Flue gas stack
  • 12. 12 COMPONENTS Main parts of the plant are 1. Coal conveyor………………………………………………………….13 2. Stoker……………………………………………………………….…..13 3. Pulveriser…………………………………………………………….....13 4. Boiler…………………………………………………………………...16 5. Air preheater…………………………………………………………….32 6. Deaerator……………………………………………………………….34 7. Turbine…………………………………………………………………35 8. Condenser……………………………………………………………….41 9. Cooling towers…………………………………………………………..43 10. Electrostatic precipitator…………………………………………..…...45 11. Smoke stack……………………………………………………………45 12. Generator………………………………………………………………46 13. Transformers…………………………………………………………...49 Conclusion…………………………………………………………………50 Reference…………………………………………………………………..51
  • 13. 13 1. COAL CONVEYOR- Coal conveyor is a belt type of arrangement. With this coal is transported from coal storage place in power plant to the place near by boiler. Adani Power Ltd. have the longest conveyor in India of 7KM long which convey the coal from the port to the plant. Phase I & Phase II Capacity : 5.50 T/ Hr / 6.6 T/Hr Phase III & Phase IV Capacity : 10-104 t/h 2. STOKER- The coal which is brought near by boiler has to put in boiler furnace for combustion. This stoker is a mechanical device for feeding coal to a furnace. It is also called feeder or hopper. 3. PULVERIZER OR COAL MILL- The coal is put in the boiler after pulverization. For this pulverizer is used. A pulverizer is a device for grinding coal for combustion in a furnace in a power plant.  Phase I & II : 5/6 mills per unit  Phase III & IV : 6 mills per unit
  • 14. 14 COAL MILL Phase I / Phase II No. of coal mills : 5 Nos. / 6 Nos. Maximum capacity : 38.7 TPH / 43.7 TPH Mill speed : 26.4 rpm No. of coal Bunkers : 5 Nos. / 6 Nos Mill type : Medium speed vertical grinder roller Make : Beijing Power Equipment Group Coal fineness : 75 µ Capacity of Bunkers : 400 MT Each Capacity of coal feeder : 50 TPH Outlet PA / Coal temp. : 85° C Coal Mill Phase III & IV No of Coal Mills : 6 nos. Mill Type : Medium Speed Bowl Mill Maximum Capacity : 86 t/h Mill Motor Rated Power : 950KW Gear Box : Spiral Bevel Gear & Planetary Mill Speed : 27.7 r/min No. of Coal Burners : 24 Type of Construction : Tangential type tilting burner Coal Feeder Type : Variable Frequency No. of Coal Bunkers : 6nos. Coal Bunker Capacity : 979 m^3. Outlet PA / Coal temp. : 85° C
  • 15. 15 Working Of Coal Mill- 1. Anthracite coal from the coal wagons is transported to the coal handling plant. 2. Here coal is crushed in crushers and reduced to 1 inch size (approx.). 3. This crushed coal is transported to the coal bunkers with the help of coal conveyers. 4. With the help of coal feeders coal from bunkers is made to fall in Coal mill. 5. Coal is grounded to powdery form in bowl mill. This finely grounded coal is known as pulverized coal. Bowl mill consists of a round metallic table and three rollers. Rotating table is made to rotate with the help of a motor. There are three large rollers which are at a spacing of 120°.When there is no coal these rollers does not rotate but when coal is fed to the table it packs between the table and the roller and this forces the rollers to rotate. Coal is crushed by the crushing action between table and rollers. 6. This pulverized coal is taken to the burner in coal pipes with the help of hot and cold air mixture from primary air (PA) fan.
  • 16. 16 4.BOILER- Now that pulverized coal is put in boiler furnace. Boiler is an enclosed vessel in which water is heated and circulated until the water is turned in to steam at he required pressure.Coal is burned inside the combustion chamber of boiler. The products of combustion are nothing but gases. These gases which are at high temperature vaporize the water inside the boiler to steam. Some times this steam is further heated in a super heater as higher the steam pressure and temperature the greater efficiency the engine will have in converting the heat in steam in to mechanical work. This steam at high pressure and temperature is used directly as a heating medium, or as the working fluid in a prime mover to convert thermal energy to mechanical work, which in turn may be converted to electrical energy. Although other fluids are sometimes used for these purposes, water is by far the most common because of its economy and suitable thermodynamic characteristics. There are two types of boiler in the power plant subcritical & supercritical 330MW unit have subcritical boiler and 660MW unit have supercritical boilers. Supercritical Technology • The supercritical technology is the thermodynamic state where there is no clear distinction between the Water and Steam phase in the Rankine Cycle • Water reaches to steam state at a critical pressure above 22.1 MPa at 374°C. Rankine Cycle • The “efficiency “of the thermodynamic process is the heat energy fed into the Rankine cycle is converted into electrical energy. • Heat energy input to the Rankine cycle is kept constant, the output can be increased by selecting high pressures and high temperatures. • The key components are supercritical once through boiler and high pressure & high temperature steam turbine.
  • 17. 17 RANKINE CYCLE SUBCRITICAL UNIT 1 – 2 > CEP work 2 – 3 > LP heating 3 – 4 > BFP work 4 – 5 > HP heating 5 – 6 > Eco. WW 6 – 7 > superheating 7 – 8 > HPT work 8 – 9 > Reating 9 – 10 > IPT work 10 – 11 > LPT work 11 – 1 > Condensing RANKINE CYCLE SUPERCRITICAL UNIT 1 – 2 > CEP work 2 – 2s > Regenration 2s – 3 > Boiler superheating 3 – 4 > HPT expantion 4 – 5 > Reheating 5 – 6 > IPT & LPT Expantion 6 – 1 > condenser Heat rejection
  • 18. 18 Difference between Sub-Critical and Super-Critical Boilers SUB-CRITICAL BOILERS SUPER-CRITICAL BOILERS Operating pressure is below 225.5 bar. Operating pressure is above 225.5 bar. circulation by pump assisted or natural circulation. Lower load start-up circulation: below 35% NR load. Power plant efficiency is around 35% Power plant efficiency is around 39% Pressure : 169 bar SH Temp : 538°C RH Temp : 538°C Pressure : 254 bar SH Temp : 571°C RH Temp : 571°C Base Additional cost to manufacturing and erection of furnace wall. Vertical water walls. Spiral wounded tilted water walls ensures: Heat distribution on each wall is more uniform than vertical water walls. Avoid higher thermal stresses in water- walls by reducing the fluid temperature difference in adjacent tubes. Steam Drum: For separation of Water and Dry-Steam. Steam Drum is not used.
  • 19. 19 Boiler Design Boiler Components  Water Walls  Separator  Economiser  Superheater  Reheater
  • 20. 20 A DETAILED VIEW OF SUPERCRITICAL BOILER
  • 21. 21 Water Walls /Evaporator – The furnace circuitry consists of a lower section with optimized, vertical rifled tubes that extend up to transition headers located at an elevation below the furnace nose. The transition headers are interconnected to provide pressure equalization to minimize flow unbalances and provide circuit flow stability. Above the transition header location, vertical smooth bore tubes extend up to the furnace roof, and also form the furnace exit screen and part of the vestibule side walls. The tube panels that form the furnace enclosure are of Monowall type construction. Risers pipes extend from the furnace enclosure upper headers and are routed to a collection manifold from which the flow is directed to a final evaporator zone that forms the furnace nose, vestibule floor and approximately half of the vestibule sidewalls. The furnace enclosure tube size and spacing were selected to provide a low mass flux (nominally 1000 kg/m2-s at full load) to provide a “natural circulation” flow characteristic (as will be described in a subsequent section) to accommodate radial heat absorption variations around the perimeter of the furnace. Tube sizes and spacing, membrane fin sizes, and materials are all selected to provide for base load service as well as the defined cyclic operation of the plant. The final evaporator zone that forms the furnace nose, vestibule floor, and part of the vestibule sidewalls is provided to act as a buffer circuit to minimize tube temperature differentials between the furnace evaporator walls and the adjacent HRA enclosure superheater panels during start-up and transient conditions. The interface between evaporator and superheater tubes is positioned near the center of the vestibule to avoid structural discontinuities such as enclosure corners where stress concentrations are the greatest. From the vestibule enclosure, steam is directed to four in-line steam/water separators connected in parallel, which are part of the start-up system, which is described below. Separator- Subcritical boilers are consist of drum arrangement and supercritical boilers are consist of separator. The separator are once through arrangement.
  • 22. 22 DRUM vs ONCE THROUGH Pressure Sub critical Sub & super critical Steam separation Drum Separator(low loads) Types Natural / assisted Sulzer / benson Burner panel Straight tube Spiral tube / straight(MHI) Load change Base Faster Cold start 4-5 Hours 2 Hours Hot start 1-2 Hours 0.5 Hours Economiser An economizer is a heat exchanger which raises the temperature of the feedwater leaving the highest pressure feed water heater to about the saturation temperature corresponding to the boiler pressure. This is done by the hot flue gases exiting the last superheater or reheater at a temperature varying from 370`C to 540`C. The throwing away of such high temperature gases involved a great deal of energy loss. By utilizing these gases in heating feedwater, higher efficiency and better economy were achieved. SH STEAM TO TURBINE HEAT DOWN COMER DRU M ECO Water Wall ORIFICE CIRC. PUMP SH STEAM TO TURBINE ECO HEAT Water Wall
  • 23. 23 The flue gases coming out of the boiler carry lot of heat. An economiser extracts a part 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. In an economizer, a large number of small diameter thin walled tubes are placed between two headers. Feed water enters the tubes through the other. The flue gases flow outside the tubes. Superheater The superheater is a heat exchanger in which heat is transferred to the saturated steam to increase its temperature. It raises the overall cycle efficiency. In addition it reduces the moisture content in the last stages of the turbine and thus increases the turbine internal efficiency. In modern utility high pressure boilers, more than 40% of the total heat absorbed in the generation of steam takes place in the superheaters. So, large surface area is required to be provided for superheating of steam. Superheaters are commonly classified as:  Ceiling Superheater:  Primary Superheater or the Low Temperature Superheater (LTSH):  Convection Superheater:  Platen or pendent panel Superheater: Ceiling Superheater: A panel of small bore tubes interconnecting long header at both ends, forms the roof of the furnace and the second pass of flue gas path. From here the steam flows through different stages of superheating.
  • 24. 24 Primary Superheater or the Low Temperature Superheater (LTSH): A panel of small bore tubes formed in “U” shaped coils is connected to long headers on either ends and located horizontally in second Pass of the flue gas path above the economizer. Superheated steam from Ceiling Superheater enters at inlet and gets heated further, raising the steam temperature. It is located in the low temperature region of flue gas path. The steam just gets superheated and the temperature range to which the steam is heated is very low compared to the final outlet steam temperature and hence called Low Temperature Superheater. Platen or pendent panel Superheater: Steam from Primary Superheater enters the Platen Superheater. The Platen Superheater is located just above the combustion zone at the top of the furnace. Mainly it receives radiant heat from the furnace and the steam is further superheated. They are hanging panels arranged in rows across the width of the furnace. Each panel is connected with its own small inlet and outlet headers, which are in turn is connected to the big and long common headers, on both inlet and outlet sides. Convection Superheater: From Platen Superheater the steam enters the next stage of superheating, which is called Convection Superheater. Convection Superheater is located away from radiant zone of the furnace and the heat transfer takes place by convection process, when the mass of flue gases pass through and across the convection Superheater coils. The steam gets its final heat addition while flowing through the final Superheater stage and flows out through main steam pipes, for the end use.
  • 25. 25 Reheater : Some of the heat of superheated steam is used to rotate the turbine where it loses some of its energy. Reheater is also steam boiler component in which heat is added to this intermediate-pressure steam, which has given up some of its energy in expansion through the high-pressure turbine. The steam after reheating is used to rotate the second steam turbine where the heat is converted to mechanical energy. This mechanical energy is used to run the alternator, which is coupled to turbine , there by generating electrical energy. Boiler Technical data:- I. Manufacturer : Harbine boiler company II. Model : HG 2115/25.4-HM15 III. Type : Supercritical once through, primary inter-mediate reheating, single furnace, II type suspended structure. IV. Type of firing : Wall mounted tangential firing
  • 26. 26 V. Water volume capacity : Economizer system – 65 m3 Water wall system – 70 m3 Start up system – 22 m3 Super heater – 227 m3 Re-heater – 435 m3 DESIGN SPECIFICATION OF THE BOILER No. Item Specification Unit 1 Model HG2115/25.4 – HM15 2 Mode Once-through boiler with supercritical pressure 3 Superheater steam flow 2115.5 t/h 4 Superheater outlet pressure 25.4 Mpa 5 Superheater outlet temperature 571 °C 6 Reheated steam flow 1714.9 t/h 7 Reheater inlet pressure 4.794 Mpa 8 Reheater outlet pressure 4.604 Mpa 9 Reheater inlet temperature 328.6 °C 10 Reheater outlet temperature 569 °C 11 Feedwater pressure 28.87 Mpa(g) 12 Feedwater temperature 292.6 °C 13 Separator’s steam temperature 421 °C 14 Air preheater’s outlet air temperature 153.3 °C 15 Uncorrected after 147.2 °C 16 Calculating thermal efficiency of boiler 92.62% (BMCR) 17 Guarantee thermal efficiency of boiler 92.17% (TRL) 18 Pulverizing type Cold primary fan positive pressure direct blowing system 19 Burner type Wall – mounted tangential circle combustion, dry ash extraction 20 Draft type Balanced ventilation 21 Design fuel Indonesian coal 22 Check fuel Indonesian coal 23 Coal-fired quantity of the boiler 338 t/h 24 Check fuel 300 t/h 25 Fuel oil startup and ignition LDO and HDO 26 Superheated steam temperature adjustment Ratio of coal and water, secondary spray desuperheating
  • 27. 27 Furnace detail Furnace dimension (width×height×height×depth)= 23567×17012×616 mm43 Horizontal pass depth : 5322 mm Back pass front duct depth : 8618 mm Break pass back duct depth : 9098 mm Water wall lower header elevation : 7000 mm
  • 28. 28
  • 29. 29 DRAUGHT SYSTEM Large amount of air is required for combustion of fuel. The gaseous combustion products in huge quantity have also to be removed continuously from the furnace. To produce the required flow of air or combustion gas, a pressure differential is needed. The term “draught” or “draft” is used to define the static pressure in the furnace, in the various ducts, and the stack. The function of the draught system is basically two folds:  To supply to the furnace the required quantity of air for complete of fuel.  To remove the gaseous products of combustion from the furnace and throw these through chimney or stack to the atmosphere. There are two ways of producing draught:  Natural draught  Mechanical draught Natural Draught: The natural draught is produced by a chimney or a stack. It is caused by the density difference between the atmospheric air and the hot gas in the stack. Mechanical Draught: Mechanical draught is produced by fans. Induced and Forced Draught Fans: Big fans may be used for sucking and throwing out the flue gas through the chimney, thereby creating adequate draught inside the furnace. Such Fans are termed as Induced Draught Fans. Forced draught Fans may also be deployed for supply of required quantity of combustion air and maintaining a positive draught inside the furnace. The flue gas will be pushed out the stack with the draught pressure available in the furnace. Forced Draught Fan: Air drawn from atmosphere is forced into the furnace, at a pressure higher than the outside atmosphere, by big centrifugal fan or fans to create turbulence and to provide adequate Oxygen for combustion. Hence the system is known by the name Forced draught system and the fan, used to push through combustion air under pressure, is called Forced Draught Fan. F D fan is normally located at the front or sideways of the furnace.
  • 30. 30 Induced Draught Fan Instead of drawing atmospheric air and pushing through furnace, a centrifugal fan can be deployed to draw out the air from the furnace and throw out through the chimney, thereby creating negative pressure in the combustion zone and maintain the negative draught through out the furnace. The system is called Induced Draught system and the fan deployed for this purpose is known as Induced Draught Fan. In the Induced Draught system, the fan is fitted at back end of the furnace or near the base of the chimney. Due to the negative pressure created inside the furnace, by the action of the fan, flue gas will not come out of combustion space i.e. Furnace. The entry of air to Boiler is regulated through air registers and dampers.
  • 31. 31 For similar capacity boilers, the size of an induced draught fan will be more than the size of the forced draught fan required for a forced draught system. This is because the products of combustion is always much higher in volume than the volume of combustion air handled by the forced draught fan. Further the flue gas is hotter and the density is less. Hence the volume is much more. According to Charles Law, when a gas is heated the volume will proportionately increase at constant pressure, with the raise in temperature. According to Boyles Law, if pressure inside a vessel is increased, the volume will proportionately decrease and the vice-versa is also true (P ∝ 1/V). Primary air fan These are the large high pressure fans which supply the air needed to dry and transport coal either directly from the coal mills to the furnace or to the intermediate bunker. These fans may be located before or after the milling equipment. The most common applications are cold primary air fans, hot primary air fans. The coal primary air fan is located before air heater and draws air from the atm. And supplies the energy required to force air through air heaters, ducts, mills and fuel piping. With a cold air system like this the FD fan may be made smaller as PA fan supply part of combustion air. For primary air fans boosts the air pressure from air heaters for drying and transporting coal from pulverisers in these systems the total air has to be handled by FD fans and each mill will be provided with a primary air fan at the mill inlet side the primary fan in these case has to handle hot air probably with some amount of fly ash carried from the air pre-heater. Technical data :- Description Unit FD PA ID Fan Model Axial Fan Axial Fan Axial Fan Rated Power of Motor kW 2000 3150 4500 Rotational Speed of Fan r/min 990 1490 990
  • 32. 32 5.AIR PREHEATER: Air preheater are in generally divided into following two types:  Recuperative  Regenerative In Recuperative APH, heat is directly transferred from the hot gases to the air across the heat exchanging surface. They are commonly tubular, although some plate types are still in use. Tubular units are essentially counter-flow shell-and- tube heat exchangers in which the hot gases flow inside the vertical straight tubes and air flows outside. Baffles are provided to maximize air contact with the hot tubes. Regenerative APH are also known as storage type heat exchangers, have an energy storage medium, called the matrix, which is alternately exposed to the hot and cold fluids. When the hot flue gases flow through the matrix in the first half of the cycle, the matrix is heated and the gas is cooled. In the next half of the Volume flow of fan inlet m^3/s 230.1 112.9 538.4 Temperature of fan inlet ˚C 47.8 47.8 137 Fan total pressure Pa 3871 12671 3989 Total efficiency % 87 88 85.5 External Diameter of Blade mm 2880 2100 3349 Diameter of Impeller mm 1600 1400 1884 Blade No. of Each Grade Nos. 26 22 18
  • 33. 33 cycle when air flows through the matrix, air gets heated and the matrix is cooled. The cycle repeats itself.
  • 34. 34 6.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 feed water. A deaerator typically includes a vertical, domed deaeration section mounted on top of a horizontal cylindrical vessel which serves as the deaerated boiler feed water storage tank.
  • 35. 35 7.STEAM TURBINE INTRODUCTION:- 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. It converts the potential or kinetic energy of the working substance into mechanical power by virtue of dynamic action of working substance. When the working substance is steam it is called the steam turbine. PRINCIPAL OF OPERATION OF STEAM TURBINE:- 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 into mechanical kinetic energy and the steam is set moving with a greater velocity. The rapidly moving particles of steam, enter the moving part of the turbine and here suffer a change in direction of motion which gives rose to change of momentum and therefore to a force. This constitutes the driving force of the machine. The processor of expansion and direction changing may occur once or a number of times in succession and may be carried out with difference of detail. The passage of steam
  • 36. 36 through moving part of the commonly called the blade, may take place in such a manner that the pressure at the outlet side of the blade is equal to that at the inlet inside.Such a turbine is broadly termed as impulse turbine.On the other hand the pressure of the steam at outlet from the moving blade may be less than that at the inlet side of the blades; the drop in pressure suffered by the steam during its flow through the moving causes a further generation of kinetic energy within the blades and adds to the propelling force which is applied to the turbine rotor.Such a turbine is broadly termed as impulse reaction turbine. The majority of the steam turbine have, therefore two important elements, or Sets of such elements.These are the nozzle in which the system expands from high pressure end a state of comparative rest to a lower pressure end a status of comparatively rapid motion. The blade or deflector, in which the steam particles changes its directions and hence its momentum changes . The blades are attach to the rotating elements are attached to the stationary part of the turbine which is usually termed the stator, casing or cylinder. Although the fundamental principles on which all steam turbine operate the same, yet the methods where by these principles carried into effect very end as a result, certain types of turbine have come into existence. 1. Simple impulse steam turbine. 2. The pressure compounded impulse turbine. 3. Simple velocity compounded impulse turbine. 4. Pressure-velocity compounded turbine. 5. Pure reaction turbine. 6. Impulse reaction turbine.
  • 37. 37 Description of Steam Turbines:- 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 inner casing too is cylinder in shape as horizontal joint flange are relieved by higher pressure arising outside and this can kept small. Due to this reason barrel type casing are especially suitable for quick start up and loading.The HP turbine consists of 25 reaction stages. The moving and stationary blades are inserted into appropriately shapes into inner casing and the shaft to reduce leakage losses at blade tips. IP Turbine:- 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 HP turbine
  • 38. 38 after reheating enters the inner casing from above and below through two inlet nozzles. The centre flows compensates the axial thrust and prevent steam inlet temperature affecting brackets, bearing etc. The arrangements of inner casing confines high steam inlet condition to admission branch of casing, while the joints of outer casing is subjected only to lower pressure and temperature at the exhaust of inner casing. The pressure in outer casing relieves the joint of inner casing so that this joint is to be sealed only against resulting differential pressure. 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. 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. The outer casing is supported by the ends of longitudinal beams on the base plates of foundation. The double flow inner casing consist of outer shell and inner shell. The inner shell is attached to outer shell with provision of free thermal movement. Steam admitted to LP turbine from IP turbine flows into the inner casing from both sides through steam inlet nozzles. Engineering Design Aspects Steam and heat cycle Type (N660.24.2/566/566) Dongfang Steam Turbine Impulse type, tandem compound three cylinders, four flow exhaust, single reheat, condensing turbine TMCR Output 660 MW BMCR Output 694 MW HP turbine 8 Stages, 2 Stop valves, 4 control valves IP turbine 6 Stages, 2 Stop valves, 2 control valves LP turbine Double flow 2x7 Stages HP heaters 3 LP heaters 4 No of Extractions 8 No of Journal bearings 6
  • 39. 39 STEAM FLOW DIAGRAM OF TURBINES AND HEATERS LOSSES IN STEAM TURBINE • Friction losses • Leakage losses • Windage loss( More in Rotors having Discs) • Exit Velocity loss
  • 40. 40 • Incidence and Exit loss • Secondary loss • Loss due to wetness • Loss at theBearings(appx 0.3% of total output) • Off design losses MAIN LOSSES IN TURBINE FRICTION LOSS- It is more in Impulse turbines than Reaction Turbines,because impulse turbines uses high velocity of steam and further the flow in the moving blades of the Reaction turbines is accelerating which leads to better and smooth flow(Turbulent flow gets converted to Laminar flow) LEAKAGES LOSS- It is more in Reaction turbines than Impulse turbines because there is Pressure difference across the moving stage of reaction turbines which leads to the Leakages. In Impulse turbine such condition is not there. • Leakage loss predominates over friction losses in the High Pressure end of the Turbine • Friction Losses predominates over the Leakage's Loss in the Low Pressure end of the Turbine. • It is observed that the Efficiency of The IP Turbine is the maximum followed by The HP and LP Turbine. Features of 660 MW Mundra Steam Turbine  Combined HP & IP Section  Shorter Turbine Length – More Efficient  Reduced No. of Bearings  Reduced No. of Packing segments  Opposite flow in HP & IP Turbines makes thrust force balanced  Casings upper & lower halves are nearly symmetrical
  • 41. 41 8.Condenser : Steam after rotating steam turbine comes to condenser. Condenser refers here to the shell and tube heat exchanger (or surface condenser) installed at the outlet of every steam turbine in Thermal power stations of utility companies generally. These condensers are heat exchangers which convert steam from its gaseous to its liquid state, also known as phase transition. In so doing, the latent heat of steam is given out inside the condenser. Where water is in short supply an air cooled condenser is often used. An air cooled condenser is however significantly more expensive and cannot achieve as low a steam turbine backpressure (and therefore less efficient) as a surface condenser. The purpose is to condense the outlet (or exhaust) steam from steam turbine to obtain maximum efficiency and also to get the condensed steam in the form of pure water, otherwise known as condensate, back to steam generator or (boiler) as boiler feed water. heat exchanger  Tubes  sea water  steam  water (condensate)  vacuum is created due to steam / condensate volume difference  vacuum is maintained by constant cool water circulation through the tubes
  • 42. 42
  • 43. 43 9.COOLING TOWERS : The condensate (water) formed in the condenser after condensation is initially at high temperature. This hot water is passed to cooling towers. It is a tower- or building-like device in which atmospheric air (the heat receiver) circulates in direct or indirect contact with warmer water (the heat source) and the water is thereby cooled. A cooling tower may serve as the heat sink in a conventional thermodynamic process, such as refrigeration or steam power generation, and when it is convenient or desirable to make final heat rejection to atmospheric air. Water, acting as the heat-transfer fluid, gives up heat to atmospheric air, and thus cooled, is recirculated through the system, affording economical operation of the process. COOLING TOWER : Inlet water temperature : 60 °C Outlet water temperature : 35 °C Output : 150 m3/h Motor Power : 7.5 kW
  • 44. 44 10.ELECTROSTATIC PRECIPITATOR(ESP) : It is a device which removes dust or other finely divided particles from flue gases by charging the particles inductively with an electric field, then attracting them to highly charged collector plates. Also known as precipitator. The process depends on two steps. In the first step the suspension passes through an electric discharge (corona discharge) area where ionization of the gas occurs. The ions produced collide with the suspended particles and confer on them an electric charge. The charged particles drift toward an electrode of opposite sign and are deposited on the electrode where their electric charge is neutralized. The phenomenon would be more correctly designated as electrode position from the gas phase.
  • 45. 45 TECHNICAL DATA 330 MW ESP ash collection 80 % (i.e.13.6 t/hr) of total ash generated. Total height of ESP 27 m Insulation Glass wool Electric insulation material Porcelain insulator Total efficiency 99.9% 1st field 80-85 % 2nd field 10-12 % 3rd and 4th field Rest 660 MW ESP ash collection 99.2 % of total ash generated. First field : 1488 second field : 210 Third field : 42 fourth field : 8 Fifth field : 2 No. of electrical fields in series : 5 11.SMOKE STACK/CHIMNEY : A chimney is a system for venting hot flue gases or smoke from a boiler, stove, furnace or fireplace to the outside atmosphere. They are typically almost vertical to ensure that the hot gases flow smoothly, drawing air into the combustion through the chimney effect (also known as the stack effect). The space inside a chimney is called a flue. Chimneys may be found in buildings, steam locomotives and ships. In the US, the term smokestack (colloquially, stack) is also used when referring to locomotive chimneys. The term funnel is generally used for ship chimneys and sometimes used to refer to locomotive chimneys. Chimneys are tall to increase their draw of air for combustion and to disperse
  • 46. 46 pollutants in the flue gases over a greater area so as to reduce the pollutant concentrations in compliance with regulatory or other limits. These are 220M tall RCC structures with single / multiple flues inside the concrete shells (one flue per 330 MW units). The height of these chimneys varies depending on the location of power plant. Stage I Chimney: 220M (two flue’s inside the outer concrete shell) Stage II Chimney: 275M (two flue’s inside the outer concrete shell) Stage III Chimney: 275M (two flue’s inside the outer concrete shell) Stage IV Chimney: 275M (three flue’s inside the outer concrete shell) 12.GENERATOR : An alternator is an electromechanical device that converts mechanical energy to alternating current electrical energy. Most alternators use a rotating magnetic field. Different geometries - such as a linear alternator for use with stirling engines - are also occasionally used. In principle, any AC generator can be called an alternator, but usually the word refers to small rotating machines driven by automotive and other internal combustion engines. Generator is connected with the all HP, IP and LP turbines so when the turbines rotates by the pressure of the steam the generator also rotate and due to magnetic field it generates electricity.
  • 47. 47 In 330MW unit the generator is connected with one HP turbine ,one IP turbine and one LP turbine but In 660MW unit the generator is connected with one HP turbine, one IP turbine and two LP turbine. Generator 330MW units Specifications Active Output 330 MW Apparent Output 388 MVA Rated Terminal Voltage 24 KV+/- 5% Rated Frequency 50 Hz +3% to -5% Rated Power Factor 0.85 lagging Phases 3 Phase Connection Star Rated Speed 3000 rpm Reference Standard IEC-34 Live Terminals brought out 3 Neutral Terminal brought out 3 Short Circuit ratio 0.60 min Short time overload capability 150% for 15 sec Class of Insulation for Stator & Rotor F Temp. Rise of Stator/Rotor Limited to Class B Cooling for Stator Core/Rotor Hydrogen Over Speed 120% for 2 mins 3 Phase short circuit withstand time 3 Sec Degree of Protection IP 54 Telephonic Harmonic interference factor Less than 1.5% Inertia Constant of Generator 2 KW sec/ KVA Type of Generator Earthing Earthed through distribution Tr.
  • 48. 48 Cooling of Stator Winding DM Water Type of Excitation Brushless without PMG DM Cold water Temp. 38 °C Cold Hydrogen gas temperature 46 °C Generator (660MW units) Specifications Manufacturer Dongfang Electric Machinery Ltd Model QFSN-660-2-2D Rated Capacity 776.5 MVA Rated Power 660 MW Rated stator voltage 22 kV, +/- 5% Rated stator current 20377 A Field Current 4476 A Phase 3 No of Terminals 6 Frequency 50 Hz Power factor 0.85 lag Rated speed 3000 rpm Wiring type Y - Y type ( Double star) Cooling method Water, hydrogen Cooling water of stator winding Directly Water cooled, Flow 102 m³/Hr Cooling Water Pressure 0.20 MPa (Stator Winding) Cooling of stator core & rotor Directly hydrogen cooled Insulation Class F Excitation Terminal, Self, static excitation. Generator rotating direction Clock wise
  • 49. 49 Rated Hydrogen Pressure 0.45 MPa (g) Max 0.5 MPa Excitation Type Static Thyristor excitation Short Circuit Ratio >= 0.5 Efficiency >= 98.8% DC Resistance of stator winding/phase 0.001196 W at 15 °C DC Resistance of field winding 0.077723 W at 15 °C 13.TRANSFORMERS : It is a device that transfers electric energy from one alternating-current circuit to one or more other circuits, either increasing (stepping up) or reducing (stepping down) the voltage. Uses for transformers include reducing the line voltage to operate low-voltage devices and raising the voltage from electric generators so that electric power can be transmitted over long distances. Transformers act through electromagnetic induction; current in the primary coil induces current in the secondary coil. The secondary voltage is calculated by multiplying the primary voltage by the ratio of the number of turns in the secondary coil to that in the primary. After generating the electricity by the generator the electricity passes through the transformers and this is how the electricity is generated.
  • 50. 50 CONCLUSION The first phase of practical training has proved to be quiet fruitful. It provided an opportunity for encounter with such hardworking engineers. The architecture of the power plant the way various units are linked and the way working of whole plant is controlled make the student realize that engineering is not just learning the structured description and working of various machines, but the greater part is of planning proper management. It also provides an opportunities to learn low technology used at proper place and time can cave a lot of labour But there are few factors that require special attention. Training is not carried out into its tree sprit. It is recommended that there should be some project specially meant for students where presence of authorities should be ensured. There should be strict monitoring of the performance of students and system of grading be improved on the basis of work done. However training has proved to be quite fruitful. It has allowed an opportunity to get an exposure of the practical implementation to theoretical fundamentals.
  • 51. 51 REFERENCES  www.adani.com  en.wikipedia.org  economictimes.indiatimes.com  energy.siemens.com  www.mapsofindia.com  www.ntpc.co.in  timesofindia.indiatimes.com  adani technical diary  adani training manual

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