APractical Training Report Undertaken at NASHIK THERMAL POWER STATION EKLAHARE, MAHAGENCO Dist. Nashik (Maharashtra) Submitted in Partial Fulfilment of the Requirement For the Award of Degree of BACHELOR OF TECHNOLOGY In Mechanical Engineering to Rajasthan Technical University, Kota 2014-2015 Submitted to: Dr. JP Bhamu Associate Professor Department of Mechanical Engineering Submitted by: Sagar Mehta B.Tech. VII Sem 11EEBME753 GOVERNMENT ENGINEERING COLLEGE, BIKANER August, 2014 ACKNOWLEDGEMENT It is often said that life is a mixture of achievements, failure, experiences, exposures and efforts to make your dream come true. There are people around you who help you realize your dream. I acquire this opportunity with much pleasure to acknowledge the invaluable assistance of Nasik Thermal Power Station and all the people who have helped me through the course of my journey in successful completion of the summer training. I would like to take this opportunity to thank all those who have contributed in this report directly or indirectly. I offer my thanks to Mr. Santosh Kulkarni (Dy. Executive Engineer), Mr. N.M. Shinde (Dy.Chief Engineer), Mr. K.M. Mane (Superintendent Engineer), Mr. Kimbahune Vikrant V. (Power User, EAM), and O.R.Usrete (Sr. Chemist) for providing whole hearted Co-operation. I would personally like to my thank Mr. A.P. Netke (Assistant Engineer and Training Incharge) for helping me throughout my training. I would like to express my sincere gratitude to Mr. Mohd. Yunus Sheikh (HOD, Department of Mechanical Engineering) and feel deep sense of gratitude towards Dr. JP Bhamu, Associate Professor in Govt. Engineering College Bikaner, being a constant source of motivation and guidance. I also like to thank all Faculty and all staff members of mechanical department of Govt. Engineering College Bikaner. I want to thank to all Staff and Workers of NTPS for their guidance and co-operation at each & every step of my training. I also acknowledge thank to my fellow students for discussing various points during the course of training which proved very useful in preparing this report. I am grateful to my friends who gave me the moral support in my times of difficulties. Last but not the least I would like to express my special thanks to my family for their continuous motivation and support. Sagar Mehta 11EEBME753 TABLE OF CONTENTS S. NO. 1 2 3 4 5 TOPICS PAGE NO. HISTORY OF POWER SECTOR 1 1.1 INTRODUCTION 1 1.2 MARKET REFORM 2 HISTORY OF INDIAN POWER SECTOR 3 2.1 INTRODUCTION 3 2.2 PRESENT ENERGY SCENARIO IN INDIA 4 HISTORY OF THERMAL POWER GENERATION 6 3.1 INTRODUCTION 6 3.2 THERMAL POWER GENERATION IN INDIA 6 NASIK THERMAL POWER STATION 7 4.1 INTRODUCTION 7 4.2 INSTALLED CAPACITY 8 4.3 TRANSPORT 9 4.4 SHAKTIMAN A SYMBOL OF VISIONARY RESOURCEFULNESS 9 STEAM POWER PLANT 10 5.1 POWER PLANT 10 5.2 STEAM POWER PLANT 10 5.3 RANKINE OR STEAM CYCLE 11 6 THERMAL POWER STATION VIEWS 13 7 POWER PLANT WATER INTAKE 14 7.1 INTRODUCTION 14 7.2 METHODOLOGY 14 8 COAL HANDLING PLANT 15 9 8.1 INTRODUCTION 15 8.2 COAL 15 8.3 TYPES OF COAL 15 8.4 COAL IN INDIA 16 8.5 GENERAL WORKING OF CHP 16 WATER TREATMENT PLANT 18 9.1 INTRODUCTION 18 9.2 WATER TREATMENT PROCESS 18 10 BOILER WATER MONITORING 21 11 BOILER, BOILER OPERATION, MAINTAINANCE AND 22 ITS AUXILIARIES 12 11.1 INTRODUCTION 22 11.2 BOILER MAIN PROCESS 22 11.3 TYPES OF BOILER USED IN POWER PLANT 22 11.4 BOILER MAIN AUXILIARIES 24 11.5 IMPROVING BOILER AND OVERALL EFFICIENCY OF PLANT 27 11.6 FLUE GAS PATH 27 11.7 BOILER AUXILIARIES SPECIFICATIONS 29 TURBINE, TURBINE OPERATION, MAINTAINANCE 31 AND ITS AUXILIARIES 12.1 INTRODUCTION 31 12.2 WORKING PRINCIPLE OF STEAM TURBINE 31 12.3 TYPES OF STEAM TURBINE 31 12.4 CONSTRUCTION AND STEAM FLOW 31 12.5 VALVES 32 12.6 TURBINE GOVERNING SYSTEM 32 12.7 OIL SUPPLY SYSTEM 33 10 STEAM TURBINE STARTS UP 36 12.2 TYPES OF COAL ASH 44 16.1 INTRODUCTION 44 16.5 AREAS OF FLY ASH UTILIZATION 45 ENERGY CONSERVATION AND ENERGY AUDIT 48 17.4 FLY ASH SYSTEM 45 16.12 MATERIALS FOR STEAM TURBINE DESIGN 36 GENERATOR 37 13.9 FIXED POINTS 33 12.13 14 15 16 17 12.3 BOTTOM ASH SYSTEM 45 16.1 INTRODUCTION 43 15.1 INTRODUCTION 37 13.2 PRINCIPLE OF GENERATION 37 STEAM CONDESING SYSTEM 39 14.11 PRECAUTIONS DURING RUNNING 36 12.2 AUDIT 48 18 CONCLUSION 49 19 SUGGESTIONS 50 .8 TURBINE MONITORING SYSTEM 33 12.2 STEAM CONDENSING SYSTEM COMPONENTS 39 BOILER FEED WATER PUMP 43 15.1 ENERGY CONSERVATION 48 17.1 INTRODUCTION 39 14.2 CONSTRUCTION AND OPERATION 43 ASH HANDLING PLANT 44 16. 8 6.19 13.1 2.2 Coal Handling Plant 16 1.3 4.1 Pre-Treatment Plant Flow Diagram 19 1.5 5.16 12.2 Typical View of Thermal Power Plant 13 1.18 13.2 Generator Transformer 36 .2 T-s Diagram of Modified Rankine (Reheat) Cycle 12 1.1 Rankine or Steam Cycle 11 1.13 11.4 5.3 Indian Generation Capacity (in MW) 5 1.1 Turbo-Generator 36 1.9 8.12 9.3 Coal and Flue Gas Cycle 26 1.1 Tangential Fired Boiler 23 1.2 Steam Turbine Rotor 33 1.2 2.2 Balance Draft Boiler 23 1.1 India’s Installed Capacity by Source 4 1.3 Energy Conversion in TPS 12 1.6 5.1 Steam Turbine and Regenerative Heating 33 1.2 Softening Plant Flow Diagram 19 1.17 12.7 6.15 11.10 8.LIST OF FIGURES AND TABLES S.1 Nashik Thermal Power Station 9 1. 1 2. FIGURE NAME PAGE NO.3 India’s GDP Variation with Energy Consumption 5 1.1 Constituents of Coal 15 1.11 9.1 Plant Layout 13 1.14 11. NO. 22 16.2 Typical View of Ash Handling Plant 47 TABLE NAME 1.1 BFP Technical Specifications 43 .1 Condenser Technical Specifications 42 1.21 16.24 8.38 14.1 River Water and Boiler Water Parameters 20 1.4 Flue Gas Parameters at Various Stages 28 1.7 PA Fan Technical Specifications 29 1.31 11.39 15.1 Diagram of Typical Water Cooled Condenser 40 1.2 Coal Feeder Technical Specifications 17 1.1.35 11.6 ID Fan Technical Specifications 29 1.36 12.2 Boiler Parameters 24 1.25 8.2 Oil Pump Technical Specifications 34 1.1 Coal Mill Technical Specifications 17 1.30 11.3 Required Boiler Auxiliaries 25 1.1 Electrostatic Precipitator 46 1.29 11.28 11.9 Air Pre-Heater Technical Specifications 30 1.20 14.34 11.5 Materials for Boiler Tubes 29 1.1 Turbine Technical Specifications 34 1.1 Capacity of Units 8 1.8 FD Fan Technical Specifications 30 1.32 11.23 4.1 Boiler Technical Specifications 23 1.26 9.27 11.37 12.33 11. Some prefer to use the term energy centre because such facilities convert forms of heat energy into electricity. At present 54. efforts to reduce these outputs are various and widespread. . The greatest variation in the design of thermal power stations is due to the different fuel sources. for district heating. or for desalination of water as well as delivering electrical power.09% or 93918. A large part of human CO2 emissions comes from fossil fuelled thermal power plants. turns into steam and spins a steam turbine which drives an electrical generator. Some thermal power plants also deliver heat energy for industrial purposes. as on 31/03/2011) of total electricity production in India is from Coal Based Thermal Power Station. 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. Water is heated. the steam is condensed in a condenser and recycled to where it was heated.ABSTRACT A thermal power station is a power plant in which the prime mover is steam driven. A coal based thermal power plant converts the chemical energy of the coal into electrical energy. this is known as a Rankine cycle. After it passes through the turbine.38 MW (Data Source CEA. Faraday devised a machine that generated electricity from rotary motion.CHAPTER 1 HISTORY OF POWER SECTOR 1. The overall effect was that Edison's system required power stations to 1 .1 INTRODUCTION: The electric power industry provides the production and delivery of electric energy. Robert Hammond. Thomas Edison developed and sold a commercially viable replacement for gas lighting and heating using locally generated and distributed direct current electricity. In time he had supplied a number of local consumers with electric light. in December 1881. It was for this reason that the generation was close to or on the consumer's premises as Edison had no means of voltage conversion. its production by this means was. Increasing the voltage reduces the current and therefore reduces the required wire thickness. The method of supply was direct current (DC). or electricity. in the US. expensive. Additionally. but it took almost 50 years for the technology to reach a commercially viable stage. Furthermore some load types were difficult or impossible to make work with higher voltages. demonstrated the new electric light in the Sussex town of Brighton in the UK for a trial period. Although electricity had been known to be produced as a result of the chemical reactions that take place in an electrolytic cell since Alessandro Volta developed the voltaic pile in 1800. The grid distributes electrical energy to customers. In 1878. Unfortunately it also increases the danger from direct contact and increases the required insulation thickness. Electric power is generated by central power stations or by distributed generation. In early 1882. It was later on in the year in September 1882 that Edison opened the Pearl Street Power Station in New York City and again it was a DC supply. and still is. In 1831. in sufficient quantities to areas that need electricity through a grid connection. The voltage chosen for any electrical system is a compromise. often known as power. Edison opened the world’s first steam-powered electricity generating station at Holborn Viaduct in London. where he had entered into an agreement with the City Corporation for a period of three months to provide street lighting. 2 MARKET REFORM: There has been a movement towards separating the monopoly parts of the industry. could be used to raise the voltage from the generators. 1. it would be unable to economically supply suburbs with power. This made it more economical to distribute power over very long distances. The DC system was able to claim slightly greater safety. Increasing the voltage reduced the current in the transmission and distribution lines and hence the size of conductors and distribution losses. While this could work in city centres.S. 2 .be within a mile of the consumers. but this difference was not great enough to overwhelm the enormous technical and economic advantages of alternating current which eventually won out. This has occurred prominently since the reform of the electricity supply industry in England and Wales in 1990. and transformers at local substations could reduce voltage to supply loads. installed at power stations. AC and DC competed for a while. with generators and retailers trading electricity in a similar manner to share and accuracy. The mid to late 1880's saw the introduction of alternating current (AC) systems in Europe and the U. Generators (such as hydroelectric sites) could be located far from the loads. such as transmission and distribution sectors from the contestable sectors of generation and retailing across the world. AC power had an advantage in that transformers. during a period called the War of Currents. In some countries. wholesale electricity markets operate. all new power generation. Enthused by the success of electricity in Calcutta.362 MW. When India became independent in 1947. The control of the company was transferred from London to Calcutta only in 1970. in late sixties. Kilburn & Co secured the Calcutta electric lighting license as agents of the Indian Electric Co.1 INTRODUCTION: The Indian Power Industry before independence was controlled firmly by the British . Hydro power and coal based thermal power have been the main sources of generating electricity. Power was available only in a few urban centres. in 1925. The concept of operating power systems on a regional basis crossing the political boundaries of states was introduced in the early sixties. State Electricity Boards (SEBs) were formed in all the states.T.S. The power sector in India has undergone significant progress after Independence. power was thereafter introduced in Bombay. which was introduced. Generation and distribution of electrical power was carried out primarily by private utility companies. the country had a power generating capacity of 1. After 1947. the company was renamed the Calcutta Electric Supply Corporation. Mumbai saw electric lighting demonstration for the first time in 1882 at Crawford Market.CHAPTER 2 HISTORY OF INDIAN POWER SECTOR 2. and Bombay Electric Supply & Tramways Company (B. On 7 January 1897. In spite of the overall 3 . In 1931.E. The first demonstration of electric light in Calcutta was conducted on 24 July 1879 by P W Fleury & Co. The first hydroelectric installation in India was installed near a tea estate at Sidrapong for the Darjeeling Municipality in 1897. The first electric train ran between Bombay's Victoria Terminus and Kurla along the Harbour Line. Nuclear power development is at slower pace. A month later.) set up a generating station in 1905 to provide electricity for the tramway. which was registered in London on 15 January 1897. transmission and distribution in the rural sector and the urban centres (which was not served by private utilities) came under the purview of State and Central government agencies. Notable amongst them and still in existence is Calcutta Electric. electrification of the metre gauge track between Madras Beach and Tambaram was started. rural areas and villages did not have electricity. compared to South Africa's 92%. After coal. the power supply industry has been under constant pressure to bridge the gap between supply and demand. Figure 2. small hydro.1 India’s Installed Capacity by Source In terms of fuel. hydroelectric about 15% and rest being a combination of wind. Thermal power plants constitute 70% of the installed capacity.34 Gigawatt (GW) as of June 2013.2 PRESENT ENERGY SCENARIO IN INDIA: The electricity sector in India had an installed capacity of 205. renewable energy for 12% and natural gas for about 9%. the world's fifth largest.development that has taken place. biomass. 2. coal-fired plants account for 56% of India's installed electricity capacity. China's 77%.e. 855 TW) electricity during 2011-12 fiscal. 4 . and Australia's 76%. renewal hydropower accounts for 19%. India generated 855 BU (855 000 MU i. waste-to- electricity. and nuclear. 2 Indian Generation Capacity (in MW) As of January 2012. China and Russia.Figure 2. Figure 2. India is the world's fourth largest energy consumer after United States.3 India’s GDP Variation with Energy Consumption 5 . one report found the per capita total consumption in India to be 778 kWh. CHAPTER 3 HISTORY OF THERMAL POWER GENERATION 3. 3. India's electricity sector consumes about 80% of the coal produced in the country.1 INTRODUCTION: Almost all coal. nuclear. The initially developed reciprocating steam engine has been used to produce mechanical power since the 18th Century. as well as many natural gas power plants are thermal. A large part of Indian coal reserve is similar to Gondwana coal. turbines offered higher speeds. with notable improvements being made by James Watt. When the first commercially developed central electrical power stations were established in 1882 at Pearl Street Station in New York and Holborn Viaduct power station in London. and stable speed regulation allowing for parallel synchronous operation of generators on a common bus. as of June 30. was 115649. turbines entirely replaced reciprocating engines in large central power stations. natural gas. reciprocating steam engines were used. solar thermal electric. agricultural waste and domestic trash / waste. 2011. petroleum products. After about 1905. more compact machinery. The state of Maharashtra is the largest producer of thermal power in the country. geothermal.48 MW which is 65. 6 . The installed capacity of Thermal Power in India. and waste incineration plants.34% of total installed capacity. Possible fuels include coal. By 1892 the turbine was considered a better alternative to reciprocating engines.2 THERMAL POWER GENERATION IN INDIA: Thermal power plants convert energy rich fuel into electricity and heat. Coal and lignite accounted for about 70% of India's installed capacity. The development of the steam turbine in 1884 provided larger and more efficient machine designs for central generating stations. The entire complex measures 472 hectare of land on the bank of river Godavari.e. steel building housing the plant and equipment in bunker bay. The first 210 MW units were synchronized on 26th April 1979 at total project cost of Rs. dust collecting plant. Turbines are also from France. Water Treatment Plant for clarified and filter water. Boilers are front fired type from Babcock Wilcock France.CHAPTER 4 NASIK THERMAL POWER STATION 4. Boilers are corner fired of American design. cooling towers with canals and CW pump houses and the power station proper with concrete stack. a large raw water reservoir divided in two halves.1 INTRODUCTION: Nashik Thermal Power Plant is located at Eklahare village near Nashik in Maharashtra. Thus total cost of Stage-II is Rs.5 crores each. Nasik Thermal Power Station comprises of 2x140 MW and 3x210 MW units.95 crores and commissioned on 10th July 1980 and 30thJanuary 1981 respectively. NTPS Stage-II comprises of three units of 210 MW each of BHEL Make. The power station campus include self contained township with all amenities. 143. 4 and 5 of 210 MW were constructed at the cost of Rs. heater bay.The cost of unit including civil work was Rs. About 100 meters away from the powerhouse stack and further beyond are the installations for fuel oil day storage and pump houses and bulk storages with pump house. it is the second highest generation company after NTPC. The power station with its auxiliary equipment comprise intake pump house on the bank of river Godavari. The power plant is one of the coal based power plants of Mahagenco (Maharashtra State Power Generation Company Limited – MSPGCL). and reservoir pump house. Turbines are of Russian design. 238. 56. 94. In terms of installed capacity. boiler plant. Unit No.73 crores. and turbine bay. The first 140 MW unit was synchronized on 16thAugust 1970 followed by second unit on 21st of March 1971. Mahagenco has the highest overall generation capacity and the highest thermal installed capacity amongst all the state power generation utilities in India. The next two units i. Near the power 7 . auxiliary reserve and unit transformers.68 crores. Beyond the turbine bay is the outdoor installation of generator transformers. The plant has 5 units under operation. 1980 Running Stage II 5 210 January. 1981 8 Running . HAL(Hindustan Aeronautics Limited). CEAT. 1971 Stopped(under renovation) Stage II 3 210 April. Raymond. surge and reclaim hoppers. Siemens. connecting belt conveyor system with inclined belt conveyors leading to the power station.2 INSTALLED CAPACITY: Nashik Thermal Power Station has an installed capacity of 890 MW. wagon tipplers. Pune & Nashik. comprising crusher house. The power plant has got ISO Certification on April 2002.1 Capacity of Units Stage Unit Number Installed Capacity (MW) Date of Commissioning Status Stage I 1 140 August.station is the coal storage yard and coal handling plant. Table 4. Gabriel. MICO. VIP. Crompton Greaves. The individual units have the generating capacity as follows. 1979 Running Stage II 4 210 July. Security Press are HT Consumers more than110 MW. 1970 Stopped(under renovation) Stage I 2 140 March. 4. NTPS… a major driving force since 1971 pouring 910 MW and an apex of Golden triangle of Mumbai. Industrial house of giants like Mahindra. No doubt it’s a symbol of innovative idea emerged in word and sprit.626. inspiring visitors that wealth from waste can be a reality.3 TRANSPORT: It is on the Bhusawal-Kalyan section of Central Railway. For example. Coal-based thermal power stations consume large quantities of coal.4. Around 80 per cent of the domestic coal supplies in India are meant for coal based thermal power plants and coal transportation forms 42 per cent of the total freight earnings of Indian railways.000 tonnes of coal in 2006-07.1 Shaktiman Statue in Guinness Book of World Records In 1991 9 . the Nasik Thermal Power Station consumed 4.4 SHAKTIMAN A SYMBOL OF VISIONARY RESOURCEFULNESS: NTPS built a scrap metal sculpture "SHAKTIMAN”. weighing 27 tones. 4. Figure 4. 17 meter tall one of its kinds in ASEA recorded in the GUINNES book of records. Figure below illustrate a fossil-fuelled power plant as a bulk energy converter from fuel to electricity using water as working medium.CHAPTER 5 STEAM POWER PLANT 5. The steam leaving the turbine condensed into water in the condenser (C) where cooling water from river or sea circulates carrying away the heat 10 . The working fluid is water. After it passes through the turbine. Oil. turns into steam and spins a steam turbine. Thorium) into shaft power into shaft work and ultimately into electricity. powerhouse. A steam power plant continuously convert the energy stored in fossil fuels (Coal. 1. Energy released by burning of fuel is transferred to water by boiler (B) to generate steam at a high pressure and temperature. Tidal Power 7. Types of energy available for generation of electrical energy are follows. Thermal Energy 2. For a steam power plant. Solar Energy 3. Water is heated. The greatest variation in the design of steam-electric power plants is due to the different fuel sources. From Gas 5. practical thermal cycle was suggested by Rankine called Ideal cycle or Rankine cycle. Wind Power 6. Atomic Energy 4.1 POWER PLANT: A power station (also referred to as generating station. Hydro Power 5. the steam is condensed in a condenser. which expands in the turbine (T) to a low pressure to produced shaft work.2 STEAM POWER PLANT: A steam-electric power station is a power station in which the electric generator is steam driven. Geo-Thermal 8. which is sometimes in liquid phase and sometimes in the vapour phase during its cycle of operations. power plant. generating plant) is an industrial facility for the generation of electric power. Natural Gas) or fissile fuels (Uranium. Boiler 2.3 THERMAL POWER STATION WORKS ON ‘RANKINE CYCLE’ Main Components of TPS 1. 5.released during condensation. Generator Figure 5. and the cycle goes on repeating itself. Boiler feed pump 5. The water (condensate) is then fed back to the boiler by the pump (P).1 Rankine or Steam Cycle 11 . Turbine 3. Condenser 4. Figure 5.3 Energy Conversions in TPS 12 .2 T-s Diagram of Modified Rankine (Reheat) Cycle Furnace Chemical to Heat Boiler Heat energy converts water to saturated Steam Generator Mechanical to Electrical Energy Turbine Kinetic energy into Mechanical Work Turbine Heat energy into Kinetic Energy Figure 5. 1 Plant Layout Figure 6.CHAPTER 6 THERMAL POWER STATION VIEWS Figure 6.2 Typical View of Thermal Power Plant 13 . CHAPTER 7 POWER PLANT WATER INTAKE 7. A dredging arrangement is there to remove the sand from front of the Pump House. To overcome from these difficulties due to polluted water. Sand also accumulates in front of pump house. Due to shifting flow of river water bunds with the help of sand bags are sometimes used to diver the flow of river water along the pump house.1 INTRODUCTION: A systematic study has been carried out to assess the water quality at downstream of Godavari river at Nashik city and its impact on Nashik Thermal Power Station. The use of Godavari river water is. These are placed in line in a common basin behind three partitioned bays. after Gangawadi. The pollution level over a period of time is increasing on the river water mainly due to sewage. 7. 14 . Trash racks are provided at the entry of each bay to arrest the floating debris coming with river water. industrial. the quality assessment of intake water of Nashik Thermal Power Station is necessary for cost effective generation. which leading to high chemical cost. There are four vertical mixed flow type water pumps. agricultural purpose and huge amount of water is also utilized by Nashik Thermal Power Station for electricity generation.e.2 METHODOLOGY: The pumping station consists of a box open on the riverside. industrial and other wastewaters are directly discharge in the river. Water samples from six sampling stations were collected monthly. equally spaced pillar walls at the inside base of the box dived the river approach into three equal bay. Eklahare. For treatment of such contaminated water huge chemicals are required for production of filtered water (sump water). Two. during period March 08 – April 09 and physic-chemical and chemical parameters were analyzed by the standard methods. All the pumps are motor driven. butterfly types discharge valves are provided for the pumps. The intake water lifted by Nashik Thermal Power Station is from downstream of the Godavari River i. mainly for domestic. Motor operated. Ultimate Analysis: Determines carbon. volatile matter and fixed carbon percentage ii. ash.3 TYPES OF COAL: According to quality (carbon content).1 INTRODUCTION: In thermal power plant coal is a principal fuel. 8. hydrogen. For calculating usefulness of coal as a fuel it is analyzed by two types Proximate Analysis: Determines moisture. sulfur and oxygen within coal. i. the coal may be divided into following classes: 15 .CHAPTER 8 COAL HANDLING PLANT 8.2 COAL: Coal is a non renewable solid fuel formed by a series of geochemical process from the plant remains accumulated together with other sediments. hence design & layout of coal handling plant is important.1 Constituents of Coal 8. nitrogen. Main constituents of coal are ffffffigFf Figure 8. iv.The good thing about Indian coal is its low sulphur content. Bituminous: . ii.It is also of good quality coal next to Anthracite. They contain 15-30% inherent moisture by weight and are non-coking. dark brown to black. It is also known as ‘brown coal’. is mainly of bituminous type of Gondwana age. The calorific value of Indian coal ranges from 4000-5000 Kcal/kg. full of moisture and volatile matter. Its carbon content is less than 50%. 8. Lignite: . It is light and woody and has poor heating capacity. It is hard and heavy and burns with great heat.It is the best quality coal and its carbon content is as much as 92% with a low volatile matter and very little moisture. Anthracite: . v.2 Coal Handling Plant 16 . Sub-bituminous coals may be dull. Sub-bituminous: -It is a type of coal whose properties range from those of lignite to those of bituminous coal and are used primarily as fuel for steam-electric power generation. soft. Coal mined in India.4 COAL IN INDIA: The common coals used in Indian industry are bituminous and sub-bituminous coal.It is inferior quality coal.i. Indian coal suffers from high ash content (15-45%) which is about 30-40%.5 GENRAL WORKING OF CHP Figure 8. Apart from low calorific value. Peat: .It is the first stage in the formation of coal. 8. Its carbon content is up to 85%. iii. For example. a pulveriser mill (Coal Mill) is used to produce pulverize coal for combustion in the steam generating furnaces of fossil fuel power plants.7 KW 17 CURRENT 7. Ball & Race Mill (Medium Speed) iii.2 Coal Feeder Technical Specifications MAKE TYPE CAPACITY MITSUBHISHI PIV ROTARY FEEDER SPEED 1430 RPM COAL 3.Coal Mill: A pulveriser or grinder is a mechanical device for the grinding of many different types of materials. Bowl Mill (Medium Speed) ii.6 KV 72 % ( 200 MESH) CURRENT 37 AMP SPEED 990 RPM 80-85 ºC Coal Feeder Table 8.1 Coal Mill Technical Specifications MAKE CAPACITY TYPE HRDGROOVE IN MILL OUTLET T BHEL MAKE BHEL 31. Ball and Tube Mill (Low Speed) TECHNICAL SPECIFICATIONS OF COAL MILL AND COAL FEEDER:Coal Mill Table 8.6 AMP VOLTAGE 415 V . Types of Coal Mills i.4 T/HR CAPACITY 320 KW XRP 763 BOWL MILLS VOLTAGE 6. Most of the period during the year.Pre-treatment Maximum impurities except total dissolved solids and colloidal silica are removed in this treatment. This water is used for cooling water system. separate arrangement of Darna River water for drinking purpose is made for NTPS colony residents. Second Stage: .1 INTRODUCTION: Nashik Thermal Power Station is situated at the bank of Godavari River at Eklahare Village. The treatment is done in two stages – i.Post Treatment a) Demineralization: . c) Domestic water: . the water contains impurities beyond removal by way of existing conventional system.CHAPTER 9 WATER TREATMENT PLANT 9. This water is fed to the boiler feed water system. b) Softening: .Perfectly pure water is produced by ion exchange process by passing the filtered water through the resins. River water contains a lot of impurities such as algae. cooling water system and for domestic purpose. various domestic effluents etc. fungi. 9. This water is fed after treatment to boiler water system. Due to deteriorated Godavari river water quality. ii.2 WATER TREATMENT PROCESS: i. Raw water quality at Nashik TPS is much typical and contaminated due to release of raw sewage.Chlorination / Bleaching Powder dosing is arranged to the filtered water so as to make it suitable for drinking purpose. ii. from up-stream. Average Incoming River water Parameters are – 18 . Godavari River is the only source of raw water for Nashik Thermal Power Station for Electricity Generation and other purpose. untreated effluents from various Chemical Industries. First Stage: .Hardness causing elements such as Calcium and Magnesium are removed in this process. dead vegetation and mineral matter in the form of dissolved solids. Bleaching CLARIFIER CHAMBER Powder (STG-2) RAPID SAND FILTERED WATER GRAVITY FILTER SUMP Figure 9. lime /bleaching powder. Reaction of which is – R.2 Softening Plant Flow Diagram R – Na + Ca / Mg Resin = R – Ca / Mg + Na Hard Water Soft Water Regeneration of Base Exchanger resin is done by using Common Salt. are added. PAC etc.Lime KmnO4 SETTLING TANK(STG-1) PUMP INTAKE PAC. FILTERED WATER SUMP FILTERED WATER PUMP BASE EXCHANGER SOFT WATER C. River water is taken at river water inlet chamber at W. T.1 Pre-Treatment Plant Flow Diagram Softening Plant: Water is passed through base exchangers where hardness causing elements i.e. Plant where the chemicals such as alum. RIVER RIVER WATER Alum. Cations (positive ions) and Anions (Negative ions) are removed from the water one by one using Resin which 19 . T.1 River Water Parameters Ion Minimum impurities (ppm) Maximum impurities (ppm) TH 90 350 TCL 20 250 Pretreatment Plant: i.Ca / Mg + NaCl Salt = R – Na + Ca / Mg Resin Effluent Demineralization: Minerals are removed from the filtered water by ion exchange process. POND Figure 9. calcium and magnesium are removed to get soft water.Table 9. 4 to 9.7 9.CO3 Mg SiO3 Reaction in Anion ExchangerCl H--. Chemical reactions in Regular Process are i.1 Boiler Water Parameters Drum Operating Pressure M/S BHEL Kg / cm2 126 – 165 Recommendation Treatment Type Phosphate Phosphate pH at 25 0 C 9. Ca Cl2 Mg Cl2 Reaction in Anion ExchangerCl R ---SO4 Cl + NaOH = ROH + Na--.4 . Reaction in Cation ExchangerNa R ---Ca Na Cl + HCl = R-H + Mg ii.SO4 SiO3 SiO3 Recommended Boiler water parameters – Stage – II (210 MW) Table 9. Reaction in Cation ExchangerNa Cl Na Ca CO3 R–H + Mg SiO3 ii. = Cl R ---Ca Resin + H --.is an organic material having the capacity to exchange ions in the water with the active group on the resin.SO4 Cl R – OH + SiO3 = R--.9.6 Conductivity at 25 0 C 100 < 35 mhos/cm 20 Parameters at NTPS .H / H2O SiO3 Chemical reactions during Regeneration Process are i.SO4 Resin + OH . water which is responsible for corrosion. 21 .CHAPTER 10 BOILER WATER MONITERING i. Colloidal Silica (which is not removed in D.9 ( which is not desirable ) is increased to about 8. Above 250 deg.P. pH of D. dosing pump. CONCLUSION: i. Nashik Road area. Nashik TPS is situated on the downstream of Godavari River and all the waste water effluents from Nashik City.8 by dosing Ammonia solution along with Hydrazine through L. Such type of contaminated water has to be treated in W. Normally the water cycle is about 10 days per month throughout the year. iii. Plant before its utilization for electricity generation. make up water at condenser is about 6. Silica in the form of silicates is hazardous in boiler water as it gets evaporated to steam and gets deposited directly on the turbine blades as too hard deposits.M. Due to these reasons. as per the agricultural requirement.NIL. water which is produced for feeding to boiler water system is having pH 7.M. vii. v. Silica . This water is very sensitive and atmospheric CO2 gets immediately mixed with it to make it acidic which is not desirable. D. M. vi. And it appears in boiler drum water. gets mixed with the Godavari River which lastly comes to NTPS Dam. 85 % of dissolved oxygen is removed in deaerator in feed water system. ii. iv. iii. Dissolved oxygen is also present in the D.0 micromhos / cm. water gets contaminated for about 200 days per year. The rotation of water is decided by the Govt. M. ii. Hydrazine dosing is arranged through L.P dosing pump at BFP suction for scavenging residual dissolved oxygen in the system water to avoid corrosion of metal surface. chemical effluent released from MIDC Industries etc. iv.0 and Conductivity less than 1. v.8 to 6. Cent. Plant) gets transformed to active silica at Temp.T. so chemical dosing is done in boiler feed water. 11. The utility boilers are large capacity steam generators used purely for the electrical power generation. Natural Circulation. Sending required amount of primary (300T/hr) and secondary air (600T/hr) to the boiler. There are many different types of boiler utilized for different purposes like running a production unit. MAINTAINANCE AND ITS AUXILIARIES 11. iv. Removing fly ash from electrostatic precipitator hoppers. Fuel (generally coal) is bunt in a furnace and hot gasses are produced. sterilizing equipment. In boiler heat energy is released from the combustion of fossils fuel and heat is transferred to different fluids in the system and a part of it is lost or left out as unutilized. v. The basic working principle of boiler is very simple and easy to understand. Supplies superheated steam (5400C) of adequate temperature and pressure to turbines.3 TYPES OF BOILER USED IN POWER PLANTS: Conventional. 11. Sending fuel (furnace oil and coal) to the boiler through dampers (3000 MT/day). Send DM water to the boiler through boiler drum to boiler tubes. Radiant Reheat Type.1 INTRODUCTION: Steam boiler or simply a boiler is basically a closed vessel into which water is heated until the water is converted into steam at required pressure. sanitizing some area.2 BOILER MAIN PROCESS: i. The boiler is essentially a closed vessel inside which water is stored. Extracting flue gases from the boiler and discharging them to atmosphere. Tangentially fired. Dry Bottom with Direct Fired Pulverized Coal with Bowl Mill or with Fuel Oil.CHAPTER 11 BOILER OPERATION. 22 . vi. Single Drum. to warm up the surroundings etc. iii. balanced draught. Removing bottom ash formed as a result of combustion process. ii. vii. Then this steam is piped to the turbine of thermal power plant. These hot gasses come in contact with water vessel where the heat of these hot gases transfer to the water and consequently steam is produced in the boiler. Figure 11.M SURFACE AREA 23 .2 Balance Draft Boiler 210 MW BOILERS TECHNICAL SPECIFICATIONS: Table 11.30% 27.8C8M 10.592M 5495 M³ TYPE FUSION WELDED TYPE LIGHT DIESEL OIL WARM UP OIL TOTAL HEATING 22862.1 Boiler Technical Specifications BOILER TYPE TANGENTIALLY FIRED OR CORNER FIRED COAL BITUMINOUS COAL FURNACE FC VM MOIST 37.60% 10% ASH GRINDABILITY CV 25% 50 HGI 5000 KCAL/KG WIDTH DEPTH VOLUME 13.1 Corner Fired Boiler Figure 11.10 SQ. unsized raw bituminous coal –crusher – bunker (stack).1 COAL CYCLE: Coal is pulverized and feed into the boiler in the following steps• Coal mine .3T/HR REHEAT STEAM TEMP @REHEAT OUTLET REHEAT STEAM PRESSURE@REHEAT OUTLET REHEAT STEAM PRESSURE@REHEAT INLET FEED WATER TEMP.to furnace for combustion.FEED WATER CYCLE: DM Water – Feed Storage Tank – Boiler Feed Pump – HP Heaters –LP Heaters – Feed Station – Economizer – Boiler Drum – Boiler Tubes BOILER PARAMETERS: Table 11. 24 .4. pulverized coal lifted by primary air and sending through coal pipes . These devices should be maintained and controlled.unshaped. so steam boiler can run in good condition. Some of auxiliaries which are installed in steam boiler are: 11.coal dampers .2 Boiler Parameters MAIN STEAM FLOW @ SH OUTLET 700 T/HR MAIN STEAM TEMP @ SH OUTLET 540 ºC MAIN STEAM PRES @ SH OUTLET 137 KG/CM² REHEAT STEAM FLOW 578.1 KG/CM² 27 KG/CM² 247 ºC 11. ECONOMISER INLET 540 ºC 25. • Powder. • Coal bunkers (20mm size coal) – coal feeders (controlling input to coal mill) – coal mills.4 BOILER MAIN AUXILIARIES: Auxiliaries of steam boiler are devices that be installed to the steam boiler. and can make it operates efficiently. 11. SEAL AIR FANS 02 NOS. when no coal firing is taking place. AT 1 ELEVATION) COAL MILLS 06 NOS. FUEL OIL PUMPS 03 NOS. OIL GUNS / IGNITORS 12 NOS.Oil Guns – To Furnace • Furnace Oil Is Non Explosive. • Forced Draft Fans: – Supplies hot air required for combustion. BOILER FEED PUMPS 03 NOS. (4 NOS. INDUCED DRAFT FANS 02 NOS. FOR ONE PASS) ELECTROSTATIC PRECIPETATOR 24 ESP FIELDS (48 HOPPERS) 11. BOTTOM ASH GRINDERS 04 NOS. the function of forced draft fan remains only to supply air required for completing combustion process.3 AIR CYCLE: • Primary Air Fans: – Mixture cold & hot air supplies to lifting coal to furnace. FORCE DRAFT FANS 02 NOS. EMERGENCY LIFT PUMPS 02 NOS. 45-60 Thousand/Kl Table 11. The function of forced draft fans is to supply the combustion air initially.4.2 FUEL (FO / LDO) OIL CYCLE: • Furnace Oil (FO) / Light Diesel Oil (LDO) Tanks – Fuel Oil Pumps – Heaters (Steam) – Oil Dampers . PRIMARY AIR FANS 02 NOS.4. But once the coal firing starts. No Spontaneous Combustion • Expensive Rs.( 2NOS.3 Required Boiler Auxiliaries BOILER AUXILIARIES QUANTITY IN NUMBERS AIR HEATERS 02 NOS. SCANNER FANS 02 NOS. Difficult To Ignite In Bulk. 25 . • Induced Draft Fans: – Maintain continuity of combustion and maintain negative pressure (-ve).Balanced draft is obtained through use of both induced and forced draft.These fans take the suction from cold air duck of primary air system & their discharge goes to the sealing of gear box of coal mills & its rollers for bearing sealing.• Balanced Draft: . • Scanner Fans: .The fuel used in thermal power plants causes soot and this is deposited on the boiler tubes. These fans take their suction from the discharge of FD in the discharge of these fans goes to scanner after getting filtered.As air supplied wet coal (Primary air) is less in quantity it is not sufficient for complete combustion & some quantity of air must be supplied additionally to complete combustion. they concentrate the cleaning through a single large nozzle rather than many small nozzles and there is no concern of nozzle arrangement with respect to the boiler tubes. In case of AC failure when FD fans trip. 26 . • Primary Air: . Scanner heads may get damaged if not cooled.This air lifts the pulverized coal from the coal mills & enters the boiler with it. air pre heaters. The other type of soot blower is the retractable soot blower. Extract flue gases from furnace and discharge them to atmosphere. • Secondary Air: . The advantages are that they are placed far away from the high temperature zone. economizer tubes. This air is also used to dry the coal. leading to outage of units. • Seal Air Fans: . This is more common with larger boilers where the flue gases have to travel a long distance through many boiler passes. This drastically reduces the amount of heat transfer of the heat exchangers. This is called secondary air. The induced draft fan works in conjunction with the forced draft fan allowing the furnace pressure to be maintained slightly below atmospheric. The primary air quantity is less with pressure higher so that it can lift the coal. etc. which may be further classified into lane type and mass type depending upon the type of spray and nozzle used. • Soot Blower System: . The types of soot blowers are fixed type. there is provision to provide suction to these fans from atmosphere.Scanner fans air supply the cooling air necessary for the cooling of costly scanner heads. Soot blowers control the formation of soot and reduce its corrosive effects. 5 IMPROVING BOILER AND OVERALL EFFICIENCY OF PLANT: • Economizer: . N2. SO2. • Reheater: . In turn this depends on the flue gas temperature leaving the boiler and the feed water inlet temperature. • Heat carried away through flue gas is used in Air Heater & Economizer to improve Boiler Efficiency.11. Superheated steam is more expansive. the steam is returned to the steam generator for reheating (in a reheater) after which it is sent to the low pressure turbine. An air preheater or air heater is a general term to describe any device designed to heat air before another process (for example. Primary steam is supplied to the high pressure turbine. The superheater consists of a superheater header and superheater elements. • Temperature of the flue gases at various stages is given below in the index for (210 MW) Rated output plant. It raises the overall cycle efficiency. water vapor produced. it reduces the moisture content in the last stages of the turbine and thus increases the turbine efficiency. The justifiable cost of the economizer depends on the total gain in efficiency. • Air Pre-Heater: -Flue gases passes through Heater tubes and Cold air passes through air heater heated up and Hot air used for combustion. After passing through the high pressure turbine.Absorbs heat from flue gas and add this sensible heat to feed water before water enters to Boiler. 11.The super heater is a heat exchanger in which heat is transferred to the saturated steam to increase its temperature.6 FLUE GAS PATH: • Whenever combustion takes place chemical energy converted into heat energy (depends on CV). combustion in a boiler) with the primary objective of increasing the thermal efficiency of the process.The reheater functions similar to the superheater in that it serves to elevate the steam temperature. In addition. They may be used alone or to replace a recuperative heat system or to replace a steam coil. 27 . • Super Heaters: . Parameters of flue gas may vary from one plant to other. Steam from the main steam pipe arrives at the saturated steam chamber of the superheater header and is fed into the superheater elements. • Various gases CO2. S.Table 11. 125 I.4 Flue Gas Parameters at Various Stages FLUE GAS PATH OUTLET TEMPERATURE 0 IN C FURNACE 1123 PLATTERN SUPER HEATER 1010 REHEATER FRONT 823 REHEATER REAR 765 FINAL SUPER HEATER 662 HORIZONTAL SUPER HEATER 479 ECONOMISER 369 AIR HEATER 140 E.P.FAN 120 CHIMNEY 120 COAL AND FLUE GAS CYCLE Coal from CHP Drum S/H R/H S/H Coal Bunker Chimney Boiler LTSH FD Fan HFO WindBox Eco Feeder ID fan APH ESP Coal Mill PA Fan Figure 11.3 Coal and Flue Gas Cycle 28 .D. Materials used for the boiler tubes as per ASME: Table 11.6 KV FAN SIZE NDF-21 b U#3 FAN SIZE NDFV-22b U#4&5 CAPACITY 70.5M³/SEC AXIAL IMPULSE 990 RPM 2 Table 11.6 CURRENT 175 138 138 TYPE SPEED NO.6 ID Fan Technical Specifications MOTOR MAKE CAPACITY UNIT NO.4 BHEL 1300 UNIT NO.5 BHEL 1300 FAN MAKE CAPACITY SPEED VOLTAGE 990 6.6 990 6. 8 % Ni Stainless Steel SA 213 T304 Up to 700oC 11. ½ % MO Steel SA 213 T11 550oC 2 ½ % Cr.5 Materials for Boiler Tubes Material ASTM Grade Temperature Specification Carbon Steel SA 210 A1 450oC Carbon ¼ % MO Steel SA 209 T1 480Oc 1 % Cr.7 BOILER AUXILIARIES SPECIFICATIONS: Table 11. OF FAN / BOILER BHEL 232.6 990 6. KKK CAPACITY 1250 KW TYPE SINGLE SUCTION RADIAL VOLTAGE 6.3 BHEL 1700 UNIT NO.33 M³/SEC SPEED 1480 RPM 29 .7 PA Fan Technical Specifications MAKE BHEL MAKE BHEL . 1 % MO Steel SA 213 T22 580oC 18% Cr. 9 Air Pre-Heater Technical Specification TYPE TRISECTOR ROTARY AIR PREHEATER(LIUNGSTORM) SIZE 27 VI 72 MAKE NO OF AIR HEATERS 2 CAPACITY 11 KW INSTALLED POSITION VERTICAL VOLTAGE 415 V 1067 MM CURRENT 22 AMP HEIGHT OF INTERMEDIATE LAYER 457 MM SPEED HEIGHT OF COLD END LAYER GAS TEMP.8 FD Fan Technical Specifications UNIT NO.6 FAN TYPE AN 20e6 U#3 CURRENT 68 79 79 TYPE OF FAN IGV OPERATIO PNEUMATIC HYDRAULIC HYDRAULIC FAN TYPE MOTOR FAN AXIAL REACTION API-18/11 U#4&5 Table 11. .5 MAKE BHEL BHEL BHEL MAKE BHEL CAPACITY 630 750 750 CAPACITY 105. 305 MM 141 ºC HEIGHT LAYER OF HOT MAIN DRIVE MOTOR CROMPTON GREAVES END DRIVE MOTOR 30 1440 RPM 2 NOS.4 UNIT NO.6 6.5 M³/SEC SPEED 990 1491 1491 TYPE OF FAN AXIAL IMPULSE VOLTAGE 6.6 6.Table 11.3 UNIT NO. The steam turbine is steam driven rotary engine. • The LPT has 4+4 stages .The common bearing of HP & IP rotor is a combined journal & radial thrust bearing. Reaction Turbine: . Such above requirement is built up in the space between two consecutive blades of fixed and moving blades rows. 12. A steam turbine works on the principle of conversion of High pressure & temperature steam into high Kinetic energy. the first stage being governing stage. TURBINES IN NTPS NASHIK: 210 MW Turbine at Nashik is three cylinders (HP. iii.3 TYPES OF STEAM TURBINE: According to the principle of action of the steam. MAINTAINANCE AND ITS AUXILIARIES 12.Steam enters at middle & flows in opposite paths having four stages. 12.In a stage of Reaction Turbine the Pressure/enthalpy drop takes place in both the fixed and moving blades. • The IPT comprises of 11 stages. For above energy conversion there is requirement of converging /ConvergingDiverging Sections. LP) Tandem compound with nozzle governing. turbine can be classified as: i. IP. ii.CHAPTER 12 TURBINE OPERATION. Impulse Turbine: .4 CONSTRUCTION AND STEAM FLOW: - 31 . • The HPT comprises of 12 stages.2 WORKING PRINCIPLE OF STEAM TURBINE: i.1 INRODUCTION: Turbine is an engine that converts energy of fluid into mechanical energy. ii. Turbine rotors are supported on five bearings . 12.In a stage of Impulse turbine the pressure/Enthalpy drop takes place only in fixed blades and not in the moving blades. Rest four bearings are journal bearings. thereby giving torque to a moving rotor.Steam Turbine Converts the Heat Energy (Kinetic Energy) into Mechanical Energy. condensing & regenerative feed heating type. The HP turbine is fitted with two initial steam stop & control valves. The steam coming from the re heater is passed to the IP part via two combined reheat stop & control valves cross around pipes connect the IP & LP cylinders. have diffusers to reduce pressure losses. they control the steam flow to the IP turbine & ensure stable operation even when turbo set is supplying only the station load. & LP parts. The IP turbine has two combined reheat stop &control valves. The HP cylinder has a throttle control. IP. All valves are individually operated by oil hydraulic servomotors. the control valves.6 TURBINE GOVERNING SYSTEM: - 32 . The stop valves are spring operated single-seat valves.5 VALVES: It is a mechanical device to control the flow of fluid in pipe. 12. are also of single seat design. In the lower load range. The lines leading from the two HP exhaust branches to the re heater are provided with swing a check valve which prevents hot steam from re heater flowing back in to the HP cylinder. The turbine is tandem compound machine with HP. The HP part is a single flow cylinder & IP & LP parts are double flow cylinders. Both the main & reheat stop & control valves are supported kinematically on foundation ceiling below the machine floor before the turbo set. The control valves. Valves are said to be nerve centre of power plant controlling high pressure steam & water. also spring loaded. The control valves operate in parallel & are fully open in the upper load range. A stop & control valve with stems arranged right angle to each other are combined in a common body. have diffusers. 12. The individual rotors & generator rotor are connected by rigid couplings. The initial steam is admitted before the blading by two combined main steam stop & control valves. Bleeds are arranged at several points of the turbine. The reheat stop valves are spring loaded single seat valves. The turbine has an electro-hydraulic governing system backed with a hydraulic governing system.9 FIXED POINTS: There is no restriction on axial movement of the casings. Bearing pedestal vibrations. The lubricating & cooling oil is passed through oil coolers before oil supply. When the turning gear is stared. obtained from bearing pedestal vibration & relative shaft vibration by calculation. measured at several points. jacking oil pumps force high pressure oil under the shaft journals to prevent boundary lubrication. The linear output frequency characteristic can be very closely set even during operation. measured at all turbine bearings. Auxiliary oil pumps maintain the oil supply on start up & shut down. 12. During turbine gear operation & when MOP is faulted. the monitoring system also includes measuring instruments & indicators for the following values. valve positions &speed. The main pump is driven by the turbine shaft draws oil from the main oil tank. 12. & operate the control valves hydraulically in conjunction with an electro hydraulic converter. An electric system measures & controls speed & output. governs the machine operates the hydraulic actuators & safety and protective devices & drives the hydraulic turning gear. 12.8 TURBINE MONITORING SYSTEM: In addition to measuring instruments & instruments indicating pressures.7 OIL SUPPLY SYSTEM: A single oil supply system lubricates & cools the bearing. Differential expansion between the shafting & turbine casing. Absolute expansion. measured at the front & rear bearing pedestal of the HP turbine. Relative shaft vibrations measured at all turbine bearings . The electro hydraulic governing system permits run up control of turbine up to rated speed & keeps speed swings following sudden load shedding low. 33 .absolute shaft vibrations. temperatures. 20 KG /CM² RATED STEAM PRESS. The method of attachment of the machine components. AF 535 ºC STEAM FLOW 616 TON/HR STEAM FLOW AT VALVE WIDE OPEN CONDITION RATED PRESSURE AT THE EXHAUST OF LPT 670 TON/HR RATED CIRCULATING WATER TEMP.1 Turbine Technical Specifications RATED OUTPUT OF TURBINE 210 MW RATED SPEED 3000 RPM RATED PRESSUE OF STEAM EMERGENCY STOP VALVE BEFORE 130 KG/CM² RATED LIVE STEAM TEMPERATURE 535 ºC RATED STEAM PRESSURE 23.HARIDWAR MAKE CAPACITY 200 KW SPEED VOLTAGE CURRENT 6. In designing the supports of the turbine on the foundation. TURBINE MAIN DATA: Table 12. which is given careful attention when determining the internal clearances in the design.PUNE 970 RPM 220 M 200 M³/HR . 30 ºC RATED QUALITY OF CIRC 27000 M³/HR 63.6 KV 21.2 Oil Pump Technical Specifications MOTOR MAKE PUMP BHEL.8 AMP HEAD DISCHARGE SPEED 985 RPM 34 MATHER & PLATT. attention is given to the expansion and contraction of the machine during thermal cycling.3 MM HG COL OIL PUMPS: Table 12. are also decisive factors in determining the magnitude of the relative axial expansion between the rotor system & turbine casings. and their coupling together. Excessive stresses would be caused in the components if the thermal expansion or contractions were restricted any way. 1 Steam Turbine and Regenerative Heating Figure 12.2 Steam Turbine Rotor 35 .Figure 12. however.12 MATERIALS FOR STEAM TURBINE DESIGN: i. If water gets into the steam and is blasted onto the blades (moisture carryover) rapid impingement and erosion of the blades can occur. then the turning gear is disengaged and steam is admitted to the turbine. After first rotating the turbine by the turning gear. along with controls and baffles in the boilers to ensure high quality steam. It is. Blades Stainless Steel – 403 & 422 (+Cr) 17-4 PH steel (+ Ti) Super Alloys Rotor High “Chrome – Moley” Steel – Cr-Mo-V Low “Ni Chrome Steel – Ni-Cr-Mo-V 36 .11 PRECAUTIONS DURING RUNNING: Problems with turbines are now rare and maintenance requirements are relatively small.10 STEAM TURBINE STARTS UP: When warming up a steam turbine for use. Also water entering the blades will likely result in the destruction of the thrust bearing for the turbine shaft. condensate drains are installed in the steam piping leading to the turbine. first to the astern blades then to the ahead blades slowly rotating the turbine at 10 to 15 RPM to slowly warm the turbine. allowing time for the rotor to assume a straight plane (no bowing). 12. which in extreme cases can lead to a blade letting go and punching straight through the casing. To prevent this. Also a turning gear is engaged when there is no steam to the turbine to slowly rotate the turbine to ensure even heating to prevent uneven expansion. essential that the turbine be turned with dry steam. possibly leading to imbalance and catastrophic failure. the main steam stop valves (after the boiler) have a bypass line to allow superheated steam to slowly bypass the valve and proceed to heat up the lines in the system along with the steam turbine. ii. 12.12. Any imbalance of the rotor can lead to vibration. is the quality of electric supply in our India.e.1 INTRODUCTION: In electricity generation. 37 . However multi pole generators are used for Hydro Power Stations as speed depends upon depth of reservoirs i.. The source of mechanical energy may vary widely from a hand crank to an internal combustion engine and turbine used in power plants. 13.2 PRINCIPLE OF GENERATION: . Magnetic field iii. Generators provide nearly all of the power for electric power grids. i. Thus maximum speed shall be achieved by 2 poles machine. water pressure. Relative speed Faraday's laws of electromagnetic induction First Law: . Second law: .CHAPTER 13 GENERATOR 13. an emf is induced in it.Whenever there is change in magnetic flux associated with a coil. Conductor ii.GENERATION OF AC POWER The basic requirements for generation of AC power are as follows. water head available at first stage of runner of turbine. a generator is a device that converts mechanical energy to electrical energy for use in an external circuit.The magnitude of induced emf is directly proportional to the rate of change of flux through the coil. Maximum electric speed to be achieved is 3000 RPM being 50 cycles per sec. 2 Generator Transformer 38 .Figure 13.1 Turbo-Generators Figure 13. Deaerator x. these systems have much lower water withdrawals than once-through systems. Condensate air extraction pump vi.2 STEAM CONDENSING SYSTEM COMPONENTS: i. Drain Cooler xii. Feed Water Heaters (HP/LP Heaters) 39 . Condenser ii. or directly from the sun or geothermal heat sources underground.CHAPTER 14 STEAM CONDENSING SYSTEM 14. Air Ejector xi. wetrecirculating systems use cooling towers to expose water to ambient air.1 INTRODUCTION: Thermoelectric power plants boil water to create steam. Condenser cooling water pump v. the rest is then sent back to the condenser in the power plant. Make up water pump ix. Because wetrecirculating systems only withdraw water to replace any water that is lost through evaporation in the cooling tower. Hot well iv. Once steam has passed through a turbine. The heat used to boil water can come from burning of a fuel. it must be cooled back into water before it can be reused to produce more electricity. Wet-recirculating or closed-loop systems reuse cooling water in a second cycle rather than immediately discharging it back to the original water source. Boiler feed pump viii. Air extraction pump vii. Colder water cools the steam more effectively and allows more efficient electricity generation. 14. Some of the water evaporates. Most commonly. but tend to have appreciably higher water consumption. Cooling tower iii. from nuclear reactions. which then spins turbines to generate electricity. Increased Plant efficiency c. They are also equipped with make-up lines from DM Storage Tank and Surge Tank. As the operating pressure of the condenser is lowered (vacuum is increased). They are maintained at required level of condensate with the help of Hot Well Level Controller. This will increase the amount of available work from the turbine (electrical output). provided just before drain cooler.Condenser: The main purposes of the condenser are to condense the exhaust steam from the turbine for reuse in the cycle and to maximize turbine efficiency by maintaining proper vacuum. Increased turbine output b. 40 . the following will occur: a.1 Diagram of a Typical Water-cooled Surface Condenser Hot Well: These are small storage tank of condensate water below condensers. Reduced steam flow Figure 14. the enthalpy drop of the expanding steam in the turbine will also increase. It is provided with continuous vent connection to condenser to maintain the flow of condensate water from condenser by neglecting its vacuum. Suction Well: This is the storage well of condensate water and condensate pump is submerged in this well. By lowering the condenser operating pressure. Cooling Towers are commonly used to provide lower than ambient water temperatures and are more cost effective and energy efficient than most other alternatives. Exhaust steam from jet ejector are made to pass from inter and after condenser where heat of jet steam is transferred to condensate coming from SPE. 41 . Part of this water will also evaporate. Cooling Tower: A cooling tower extracts heat from water by evaporation. which are drained to the condenser through an atmospheric drain tank. Air Ejector: It is a double stage twin steam jet ejector which acts as an air pump. Steam Packing Exhauster (SPE): This is a surface type heat exchanger which transfers the heat energy of packing steam to the condensate water and condenses packing steam (drip) in turn. it is pumped to the top of the cooling tower and will then flow down through plastic or wood shells. In an evaporative cooling tower. It delivers condensate to SPE. The pipes are obviously much larger to accommodate this much water in the larger towers and can range up to 12 inches in diameter. Its shell is equipped with an Air Blower to evacuate non-condensable gases to atmosphere. Its main function is to maintain vacuum by pulling out air and non-condensable gases from the condenser. much like a honeycomb found in a bee’s nest. causing it to lose even more heat. which in turn cools the water. When water is reused in the process.Condensate Pump: There are two multistage centrifugal condensate pumps but both are capable of delivering full load individually. a small portion of the water being cooled is allowed to evaporate into a moving air stream to provide significant cooling to the rest of that water stream. The water will emit heat as it is downward flowing which mixes with the above air flow. The smallest cooling towers are structured for only a few litres of water per minute while the largest cooling towers may handle upwards of thousands of litres per minute. OF COOLING TUBE NO. The bled steam directly condenses and gets mixed with condensate water from heater. condensing and overcooling areas. Condenser Data: Table 14.Drain Cooler: The air from condensate water. Use one or more high pressure feed water heaters to raise the temperature of feed water from de-aerator outlet temperature to the required boiler economizer inlet temperature. making it difficult to design and produce. Use one or more low pressure feed water heaters to raise the temperature of condensate from condensate pump discharge temperature to the de-aerator inlet temperature.1 Condenser Technical Specifications MAKE COOLING SURFACE AREA NO. condensing areas. 1 NO . OF COOLING TUBES LENGTH OF COOLING TU DIA. dissolved oxygen in boiler feed water will cause serious corrosion damage in steam boiler systems by attaching to the walls of metal piping and other metallic equipment and forming oxides (rust). which is exhausted to atmosphere through a vent condenser. Feed Water Heaters: This item is installed to improve power generator efficiency by heating supplied water and reducing breakage due to heat stress from temperature differences in boiler tubes. and this is passed to storage tank. In particular. Because a single heater consists of cooling areas. Deaerator: A deaerator is a device that is used for removal of oxygen and other dissolved gases from the feed water to steam-generating boilers. Feed water heaters are classified as low and high pressure heaters with one heater consisting of overheating. this item requires thoughtful engineering and production. OF WATER PATHS FOR EACH CONDENSER DESIGNED CONSUMPTION OF COOLING WATER QUANTITY OF STEAM CONDENSING MAIN EJECTOR STARTING EJECTOR 42 BHEL 14650 M² 15652 10M 30/28 MM 2 27000 M³/HR 150 TO 500 T/HR 2 NOS. and heating areas. HARDWAR MAKE BHEL. The minimum flow usually returns to the tank or deaerator. the pump must generate sufficient pressure to overcome the steam pressure developed by the boiler. Another common form of feed water pumps run constantly and are provided with a minimum flow device to stop over pressuring the pump on low flows.6 KV 408 AMP 1485 RPM TYPE NO. Large industrial condensate may also serve as the feed water pump.2 CONSTRUCTION AND OPERATION: Feed water pumps range in size up to many horsepower and the electric motor is usually separated from the pump body by some form of mechanical coupling.1 BFP Technical Specifications MOTOR PUMP MAKE BHEL .CHAPTER 15 BOILER FEED WATER PUMP 15. This is usually accomplished through the use of a centrifugal pump. 15. In either case. These pumps are normally high pressure units that take suction from a condensate return system and can be of the centrifugal pump type or positive displacement type. to force the water into the boiler.HYDERABAD CAPACITY VOLTAGE CURRENT SPEED 4000 KW 6.OF STGES SPEED LUBRICATION 200 KHI 6 4320 RPM FORCED HEAD 1830 MLC DISCHARGE 430 T/HR 43 . The water may be freshly supplied or returning condensate produced as a result of the condensation of the steam produced by the boiler. Boiler Feed Pump Data: Table 15.1 INTRODUCTION: A boiler feed water pump is a specific type of pump used to pump feed water into a steam boiler. 3276*0. Indian coal has Calorific Value.65 kg coal. Ash content is 28% I. as per design we have to burn 0.e.55 kg coal. Fly Ash: .Collected at the bottom of boiler furnace.2 TYPES OF COAL ASH: Coal ash is the residue of the coal combustion process involved in the thermal power plants.e.e.e. Out of this 28% ash Bottom ash 15 to 20% i. iii.65*5. Pond Ash: . One 210 mw set requires 0.28 tonne i. 734 to 780 tonne Contents of ash Silica Alumina Iron oxide 44 .1 INTRODUCTION: To generate one unit.28=917.Mixture of bottom ash and fly ash as available in ash disposal ponds.04*1000=3276 tonne coal per day.5000 Kcal/ Kg.Collected from different rows of electrostatic precipitator. But actually we have to burn 0. 138 to 184 tonne Fly ash 80 to 85% i.CHAPTER 16 ASH HANDLING PLANT 16. 920 tonne. 16. Bottom Ash: . The types of coal ash from coal based thermal power plants are: i. ii. Fixed Carbon – 38% Volatile Matter – 26% Moisture – 8% Ash Content – 28%. 3 BOTTOM ASH SYSTEM: It consists following main components: Bottom ash hopper Clinker grinder Ejector feed pump Hydro ejector 16. Two slurry pumps are provided which is common to all units & used to make slurry and further transportation to ash dyke through pipeline. Components in ESP: • Discharge electrode (-ve) • Collecting electrode (+ve ) • Rapping mechanism • Fly ash hopper • High tension voltage equipment 16.5 AREAS OF FLY ASH UTILISATION: Fly ash can be used for various applications. Ash particles are separated by passing through electrical field (Electrostatic Precipitator). Calcium Magnesium Sulphate Alkalis 16.4 FLY ASH SYSTEM: The system for all units is identical and following description is applied to both the units the water compounded bottom ash hopper receives the bottom ash from the furnace from where it is stores and discharged through the clinker grinder. Some of the major areas of fly ash utilization are as follow: Fly ash bricks Fly ash cement Reclamation of waste land 45 . Sintered aggregate Wood substitute – doors & panels Granite substitute Ceramic tiles Paints & enamels Reclamation of ash ponds for human settlement Figure 16.1 Electrostatic Precipitator Common causes of unsatisfactory performance of ESP are: Excessive gas volume Overloading Ineffective rapping 46 . Fly ash based components for construction industry. Overfilling of dust hoppers Poor gas distribution Flashover and electrical instability Discharge wire breakage Fig 16.2 Typical View of Ash Handling Plant 47 . When the object of study is an occupied building then reducing energy consumption while maintaining or improving human comfort. political and environmental sustainability. process or system to reduce the amount of energy input into the system without negatively affecting the output. national and personal security.CHAPTER 17 ENERGY CONSERVATION AND ENERGY AUDIT 17. energy conservation is an important method to prevent climate change. 48 . Beyond simply identifying the sources of energy use. Energy conservation is often the most economical solution to energy shortages. This practice may result in increase of financial capital. In general. an energy audit seeks to prioritize the energy uses according to the greatest to least cost effective opportunities for energy savings.2 ENERGY AUDIT: An Energy Audit is a systematic exercise to identify end-uses that consume a significant amount of energy. survey and analysis of energy flows for energy conservation in a building. This reduces the rise in energy costs. and human comfort. and can reduce the need for new power plants. health and safety are of primary concern. On a larger scale. Individuals and organizations that are direct consumers of energy may want to conserve energy in order to reduce energy costs and promote economic. energy conservation is an important element of energy policy.1 ENERGY CONSERVATION: Energy conservation means to reduce the quantity of energy that is used for different purposes. By reducing emissions. The reduced energy demand can provide more flexibility in choosing the most preferred methods of energy production. environmental value. It attempts to balance the total energy inputs with its use and serves to identify all the energy streams in a facility. and energy imports. 17. estimate the efficiency in each of these end uses and devise methods of improving efficiency curbing losses and wasteful use or in other words it is an inspection. Energy conservation makes it easier to replace non-renewable resources with renewable energy. energy conservation reduces the energy consumption and energy demand per capita. delivers satisfactory financial Parameters as per base financial model. But there are few factors that require special mention. boiler and generator. Assessment of the financial feasibility of the Proposed Project.CHAPTER 18 CONCLUSION It was a knowledgeable experience while taking practical training at NASHIK THERMAL POWER STATION. 49 . a thermal power project is very large establishment with many components and it awesome to see how all the components work in a synchronized manner. Company has proposed to set-up 660 MW Coal fired Thermal Power Project based on Super Critical Technology. The Electricity Act 2003 and subsequent National Electricity Policy and Tariff Policy have Opened up several opportunities for the power sector. All in all. Well. Slowly open access in distribution system is also being allowed. From all the study it can be concluded that the Nasik thermal power project of 210X3 units is fairly organized unit with the latest machinery available. which could be at variance with the base case scenario assumed. Another interesting yet worrying fact is the quantity of coal consumed which approximately 3276 tonne per day. efforts are always underway in reducing the pollution and improving the efficiency of the plant. but still I consider it to be quite enough. The Act allows the IPPs and captive Power producers open access to transmission system. It proved an opportunity for encounter with such huge machines like tippler. turbine. The turbine is a very sophisticated assembly of machinery which requires specific conditions of steam temperature and pressure to work efficiently. Any alteration of the specific requirements may prove hazardous to the turbine. thus allowing them to bypass the SEBs and sell power directly to bulk consumers. The level of pollution is always controlled according the established norms. It has also assessed the viability of the project under the impact of various scenarios. State Government has supported this Project and has issued letter of support to provide all kind of administrative support required. but the main concern is the cleanliness of plant. What I believe is that cleaner environment might help in improving of productivity and decrease the rate of breakdowns. It plays a vital role in the socio-economic development.CHAPTER 19 SUGGESTIONS Power sector is an essential service and in the basis of industrialization and agriculture. The plant. NTPC. Turbine driven Boiler Feed Pumps should be used. the coal consumption will be reduced for the same load and that would provide better profit to the organization. several actions have already been initiated by Ministry of Power (MOP) and other various agencies like CEA. With this objective in view. especially 140X2 units building of the plant is not clean enough. If the efficiency increases. there is need of many projects and the exposure limit should be increased to effectively assist the new projects. Recover the portion of heat loss from the warm cooling water existing the steam condenser. water. State Electricity Boards. Reduce air. Use of automatic system for monitoring flue gases. Variable speed motors should be used. Now I here make it sort with my suggestions for improving efficiency of power plant and for various other factors on the basis of what I have learned during my training are: With the deficit of electricity in our country. 50 . steam and flue gas leakages. The plant is working fine with not many hindrances. This might improve the efficiency of the unit as lesser number of foreign elements will be present which prevent the proper functioning of the unit. Therefore. to improve the operating efficiency and PLF of thermal power stations. Auxiliaries power reduction. improving efficiency of these thermal power stations in addition to increasing their PLF (Plant Load Factor) has become the need of the hour to bring the cost and maximize the generation levels. Proper maintenance of ESP must be done with regular maintenance of boilers and furnaces. Completely insulate the steam system. CBIP etc.
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