Assembly of High Pressure Module of Steam Turbine

We would like to express our heartfelt gratitude towards Shri Jagarnath Orav (Senior Manager, IMM) for guiding us and giving us his invaluable and precious time.He directed us to learn about the machines, which were new to us. Without his help and support the completion of this project would have been a very difficult task. We would also like to thank our instructor Shri Satish Kumar Dubey who helped us enormously throughout. We would also like to thank Shri J. C. Sharma and Shri Suresh Nema (HRDC) for helping us in the allocation of appropriate departments and in a hundred little ways.Thanking the dedicated officials and staff of Steam Turbine Department, we would like to make a special mention of Shri Anand Dubey, Shri Sudipto, Shri Sumesh for giving us practical knowledge and day to day utility of the subject. We would also like to thank Shri R. B. Patil (AGM, Steam Turbine) for providing his constant help and support. Last but not the least, we would like to thank BHEL for providing us the platform to enhance our practical knowledge. APOORV MOHAN SHRIVASTAV (REG NO- 100934207) MANIPAL INSTITUTE OF TECHNOLOGY , MANIPAL, KARNATAKA- 576104 Station : BHEL (Bharat Heavy Electricals Limited) * Centre : Bhopal (Madhya Pradesh) * Duration: 4th July 2013 to 31st July 2013 * Date of submission : 31st July 2013 * Title of the project : Assembly of High Pressure Module of Steam Turbine. * Name of student: Apoorv Mohan Shrivastav * Discipline: B. E.Automobile Engineering Name of expert Designation Shri Jagarnath Orav, Senior Manager, Industrial Machine Manufacturing Division, BHEL, Bhopal Key words : Rotor, Inner Casing, Outer Casing, Blades ABSTRACT The basic aim of the project is to understand the working and assembly of steam turbine. The project lays stress on high pressure module of the steam turbine. For this, BHEL has provided us a platform to visually understand the assembly of Parli Project, which is undergoing in the shop unit. It basically consists of inner casing, outer casing, blades and rotor. The principle used in steam turbine is the temperature entropy curve.High pressure module is coupled with intermediate pressure module which is coupled with low pressure module which is further connected to boiler. High pressure part is in turn connected to condenser and generator and hence is used in the production of electricity. The Parli project in BHEL Bhopal of high pressure module of steam turbine is based on barrel system and hence all assembly is done vertically. Time taken is approximated to be around 25 days. ?? ? ? ? ? ? ? ? ? ? ? ? FOREWORD ? BHEL(Bharat Heavy Electricals Limited) is country’s premier Engineering organization and one of the Navratna PSUs which provides world class roducts and services in Power Transportation , Transmission and electronics sectors having manufacturing and services division spread all over the country and also across 70 countries around the world. The headquarters of BHEL is located in New Delhi. BHEL is currently 12th largest electrical products manufacturer in the world. Main manufacturing units of BHEL are located in India at Haridwar, Bhopal ,Hyderabad, Tiruchirapalli, Jhansi, Ranipet, Bangalore, Jagdishpur, Rudrapur, Goindwal and Vizag, besides these several ancillary and feeder units of BHEL are spread all across the country.Currently BHEL has manufacturing capability up to 15000MW per annum, in India BHEL is responsible for generation of 75% of country? s total power. BHEL (Bharat Heavy Electricals Limited) came to existence on 29th August, 1956 in Bhopal ,in collaboration with a vision of making India self-sufficient in its power needs . Heavy Electrical Plant Bhopal is the mother plant of the Bharat Heavy Electricals Limited. BHEL Bhopal has its own laboratories for material testing, the laboratories are accredited with ISO 17025 by NABL, and material testing labs come under TSD (Technical Services Division) of BHEL, Bhopal.The Ultra High Voltage labs, Electric Calibration labs are highly advanced and one of the best in South Asia. ?? ? INTRODUCTION History BHEL (Bharat Heavy Electricals Limited) is an integrated power plant equipment manufacturer and one of the largest engineering and manufacturing companies in India in terms of turnover. Established in 1964, BHEL ushered in the indigenous Heavy Electrical Equipment industry in India – a dream that has been more than realized with a well-recognized track record of performance. The company has been earning profits continuously since 1971-72 and paying dividends since 1976-77.BHEL is engaged in the design, engineering, manufacture, construction, testing, commissioning and servicing of a wide range of products and services for the core sectors of the economy, viz. Power, Transmission, Industry, Transportation, Renewable Energy, Oil & Gas and Defence. The company has 15 manufacturing divisions, two repair units, four regional offices, eight service centres, eight overseas offices and 15 regional centres and currently operates at more than 150 project sites across India and abroad.The company places strong emphasis on innovation and creative development of new technologies. The company has realized the capability to deliver 20,000 MW p. a. of power equipment, enabling to address growing demand for power generation equipment. Achievements Most of the manufacturing units and other entities have been accredited to Quality Management Systems (ISO9001:2008), Environmental Management Systems (ISO 14001:2004) and Occupational Health & Safety Management Systems (OHSAS 18001:2007).BHEL, where Quality Systems as per ISO-9000 have taken deep roots has made significant achievements in the CII Exim Award Scheme for Business Excellence by securing ‘Commendation for Significant Achievements in TQM’ for three of its manufacturing units and one power sector-region during 2011-12. Power Generation In Power generation segment, BHEL is the largest manufacturer in India supplying a wide range of products and systems for thermal, nuclear, gas and hydro-based utility and captive power plants. BHEL has the capability to execute power projects on turnkey/EPC basis from concept-to-commissioning.BHEL supplies steam turbines, generators, boilers and matching auxiliaries up to 800 MW ratings, including sets of 660/700/800 MW based on supercritical technology. BHEL has facilities to go up to 1000 MW unit size. To make efficient use of high ash content coal available in India, BHEL also supplies circulating fluidized bed combustion (CFBC) boilers for thermal plants. BHEL is the only Indian company capable of manufacturing large-size gas-based power plant equipment, comprising of advanced-class gas turbines up to 289 MW (ISO) rating .A 500-MW boiler drum made by BHEL being sent to an NTPC unit Industries BHEL is a leading manufacturer of a variety of Industrial Systems & Products to meet the demand of a number of industries, like metallurgical, mining, cement, paper, fertilizers, refineries & petro-chemicals etc. besides Captive and Industrial utilities. BHEL has supplied systems and individual products including a large number of co-generation Captive power plants, Centrifugal compressors, Drive Turbines, Industrial boilers and auxiliaries etc. TransportationMost of the trains of Indian Railways, whether electric or diesel powered, are equipped with BHEL’s traction propulsion system and controls. The range includes traction motors, traction generators/alternators, transformers, substation equipment. The systems supplied are both with the conventional DC and state-of–the-art AC drives. India’s first underground metro at Kolkata runs on drives and controls supplied by BHEL. In the last financial year 2012-2013, BHEL signed a MoU with the Indian Railways for setting up Greenfield coach factory for mainline electric multiple systems. Electric Locomotive (25 kV AC, Type WAG 7)Renewable Energy In conformity with its concern for the environment, BHEL has been contributing to the national effort for developing and promoting renewable energy based products on a sustained basis. With an aim to perform a significant role in National Solar Mission’s proposed target of 20,000 MW of grid connected solar power, BHEL signed an agreement with Abengoa, Spain, a leader in solar projects to provide EPC solutions in CSP Concentrated Solar Thermal Power Plant areas. Country’s Largest Diesel Grid-Interactive Solar Power Plant of 760 kWp capacity, commissioned by BHEL at LakshadweepThe company commissioned a 5 MW grid connected Solar Photovoltaic Plant for KPCL at Mandya, Karnataka and highest rating SPV Power Plant of orders of 10 MW each from Unachahar and Talcher. Transmission The products manufactured by BHEL include Power transformers, SF6 switchgear; Gas insulated switchgears, Ceramic insulators, etc. BHEL has successfully designed, manufactured and commissioned India’s highest voltage Power Transformer of 1200 kV 333 MVA rating at the 1200 kV National Experimental Substation of PGCIL.BHEL is executing the world’s first + 800KV 6,000 MW Ultra High Voltage Multi-Terminal DC Transmission link between North-East and Agra. BHEL has the expertise and extensive on-the job exposure for design and applications relating to Power System Studies and Feasibility Studies etc. 400 kV Substation executed by BHEL for PGCIL Research and Development In the financial year 2012-13, 385 patents were filed- highest ever in a year. The company’s intellectual capital stands at 2170 patents and copyrights. The company has earned 9,643 crore Rupees from in-house developed products and services, 19. 3% of the turnover of the company.In conformity with engineering and technology objective, the Corporate R;amp;D Division at Hyderabad leads BHEL’s research efforts using emerging technologies to offer state-of-the-art total engineering solutions. Research and product development centers at each of the manufacturing divisions play a complementary role. In order to facilitate advanced R;amp;D activities in focused areas with state-of-the-art facilities and specialized manpower, BHEL has TABLE OF CONTENTS Certificate…………………………………………………………………… 2 Acknowledgement……………………………………………………………3 Abstract……………………………………………………………………… 5 Foreword…………………………………………………………………….. Introduction( About BHEL)…………………………………………………. 7 Introduction to steam Turbine……………………………. …………………. 12 History of Steam Turbine……………………………………………………. 13 How did it all start?……………………………………………………………………………… 13 What made Steam Turbine so different?…………………………………………………. 13 What were the first steam turbines used for?……………………………………………. 14 Steam Turbine Basics…………………………………………….. …………. 14 Types of Steam Turbine………………………………………. …………….. 16 Impulse Turbine Mechanism…………………………………… …………. 16 Reaction Turbine Mechansim…………………………………… …………… 17 Principle of working…………………………….. …………………………… 19 Project Report………………………………………………. …………………21 Aim……………………………………………………………………………. 21 Components……………………………………………………………………21 Major components…………………………………………. …………………. 21 Minor components………………………………………. ……………………. 21 Requirements………………………………………………………………… . 22 Methodology…………………………………….. ……………………………. 23 Outer Casing……………………………………………. …………………….. 24 Inner Casing………………………………………… …………………………. 25 Rotor……………………………………………………………………………26 Time Line………………………………………………………………………. 6 Conclusion………………………………………………………………. …….. 27 Departments Visited……………………………………………………. ……… 27 References………………………………………………………. …………….. 28 Introduction to Steam Turbine A steam turbine is a mechanical device that extracts thermal energy from pressurized steam, and converts it into rotary motion. Its modern manifestation was invented by Sir Charles Parsons in 1884. Definitions of steam turbine: * A turbine in which steam strikes blades and makes them turn * A steam turbine is a mechanical device that extracts thermal energy from pressurized steam, and converts it into rotary motion.Its modern manifestation was invented by Sir Charles Parsons in 1884. * A system of angled and shaped blades arranged on a rotor through which steam is passed to generate rotational energy. Today, normally used in power stations. * A device for converting energy of high-pressure steam (produced in a boiler) into mechanical power which can then be used to generate electricity. * Equipment unit flown through by steam, used to convert the energy of the steam into rotational energy. A machine for generating mechanical power in rotary motion from the energy of steam at temperature and pressure above that of an available sink.By far the most widely used and most powerful turbines are those driven by steam. Until the 1960s essentially all steam used in turbine cycles was raised in boilers burning fossil fuels (coal, oil, and gas) or, in minor quantities, certain waste products. However, modern turbine technology includes nuclear steam plants as well as production of steam supplies from other sources. The illustration shows a small, simple mechanical-drive turbine of a few horsepower. It illustrates the essential parts for all steam turbines regardless of rating or complexity: 1) A casing, or shell, usually divided at the horizontal centre line, with the halves bolted together for ease of assembly and disassembly; it contains the stationary blade system; (2) A rotor carrying the moving buckets (blades or vanes) either on wheels or drums, with bearing journals on the ends of the rotor; (3) A set of bearings attached to the casing to support the shaft; (4) A governor and valve system for regulating the speed and power of the turbine by controlling the steam flow, and an oil system for lubrication of the bearings and, on all but the smallest machines, for operating the control valves by a relay system connected with the governor; (5) A coupling to connect with the driven machine; and (6) Pipe connections to the steam supply at the inlet and to an exhaust system at the outlet of the casing or shell. Steam turbines are ideal prime movers for driving machines requiring rotational mechanical input power. A History of Steam TurbinesThe Steam Turbine is one of the most important inventions in the world, as far as engineering is concerned! Steam turbines are devices that convert the mechanical energy of high pressure steam or water vapor, into electrical energy by the use of a generator. How Did It All Start ? Ever since the industrial revolution in Britain, focus shifted on completion of work automatically. This basically meant the use of resources such as coal to produce heat or thermal energy to evaporate water to steam, that could in turn be used to do useful work such as producing motion or performing industrial tasks like lifting (pneumatics), which were otherwise difficult to perform by direct human effort.The invention of the steam engine by James Watt saw the viable use of steam as a working fluid, and hence, the steam turbine was invented and improved upon, based on the same line of thought. What Made Steam Turbines So Different? The steam turbine revolutionized the power production industry, and the steam turbine literally changed the world in a matter of a few years! Steam turbines effectively converted mechanical energy into electrical energy and the processes used initially were also easy to manage, in spite of having great room for improvement, which was later done by other engineers and scientists anyway. While the steam engine focused on using steam to rotate the wheels of the train or car, the steam turbine worked to rotate the blades of a windmill like structure (the turbine itself) by rotating its blades.Fundamentally, they are pretty much alike, but instead of generating motion alone, turbines generated electricity, which is easy to store, transport and share. Electricity could be used to perform a wide range of tasks that were not necessarily mechanical in nature, such as lighting bulbs and providing heat! This was the main reason that propelled steam turbines to become the prime focus of engineers of the time. What Were The First Steam Turbines Used For? Though you may find it quite unbelievable, initially the steam turbine was a mere toy, used by the ancient Egyptians! Later on, the steam turbine was used to rotate cooking aids such as spits, also in Egypt.Steam turbines have, as you can see, long been used to do useful work. However, the main focus of scientists and engineers after the industrial revolution was the use of steam turbines to produce electricity by moving the armature arms of the electrical generator. Putting it technically, the generator armature is rotated due to the rotary motion of the turbine, which is in turn because of the force of the impending steam on the turbine blades. Steam Turbines were then used in producing motion, though only for a short period of time. Steam turbines were used in ships to propel them forward more efficiently, and this was also an area of high interest. Steam Turbines BasicsThough “Steam Turbines” might sound like a technical term, most of the things we do every day would be impossible to do without this wonderful technology in power generation. Nature does not have sockets from where power plants pull out electricity to run your laptop or charge your iPod! Energy needs to be converted to electricity or electrical energy, from its natural occurrences. Steam Turbines are devices that help in the production of electricity, by converting mechanical energy into useful electrical energy! The Steam Turbine was invented by Parson, more than a century ago, and it has gone through numerous changes to become an effective power generator in today’s power plants. A large percentage of world’s power generation is achieved using steam turbines.The advantage of power generation using steam turbines are The physical properties of steam (used as energy source for the turbines) are predictable at various pressures ;amp; temperatures and are constant across the globe. The Steam turbine designs are scalable, and can be design to suit any application. A Steam turbine separates the energy source and electrical power generation, making it compatible with various sources of fuels as feedstock (Coal, biomass, Municipal Waste, Gas), unlike a gas turbine, gas engine, diesel sets etc. Combined heat and power can be handled by steam turbines effectively, making it a widely used mode of power generation in process industry.By virtue of its operational characteristics (starting time and reliability) these turbines suits better, catering to the base load operation in modern power systems. Basic Types of Steam Turbines The two most basic and fundamental types of steam turbines are the impulse turbine and the impulse reaction turbine. The Impulse Turbine: The impulse turbine consists of a set of stationary blades followed by a set of rotor blades which rotate to produce the rotary power. The high pressure steam flows through the fixed blades, which are nothing but nozzles, and undergo a decrease in pressure energy, which is converted to kinetic energy to give the steam high velocity levels. This high velocity steam strikes the moving blades or rotor and causes them to rotate.The fixed blades do not completely convert all the pressure energy of the steam to kinetic energy, hence there is some residual pressure energy associated with the steam on exit. Therefore the efficiency of this turbine is very limited as compared to the next turbine we are going to review- the reaction turbine or impulse reaction turbine. The impulse turbine was one of the basic steam turbines. It involved striking of the blades by a stream or a jet of high pressure steam, which caused the blades of the turbine to rotate. The direction of the jet was perpendicular to the axis of the blade. It was realized that the impulse turbine was not very efficient and required high pressures, which is also quite difficult to maintain.The impulse turbine has nozzles that are fixed to convert the steam to high pressure steam before letting it strike the blades. Impulse turbine mechanism – Impulse turbine Mechanism deals with the Impulse force action-reaction. As we all know the Newton 3rd law of motion,” Every action has equal and opposite reaction”, the same is work on this. As the water fall on the blade of the rotor it generate the impact force on the blade surface, The blade tends to give the same reaction to the fluid, but the rotor is attached to the rotating assembly, it absorb the force impact and give the reaction in the direction of the fluid flow. Thus the whole turbine rotates.The rotation speed of the turbine depends on the fluid velocity, more the fluid velocity, greater the rotation speed, and greater the speed means more power generation. The Reaction Turbine: The reaction turbine is a turbine that makes use of both the impulse and the reaction of the steam to produce the rotary effect on the rotors. The moving blades or the rotors here are also nozzle shaped (They are aerodynamically designed for this) and hence there is a drop in pressure while moving through the rotor as well. Therefore in this turbine the pressure drops occur not only in the fixed blades, but a further pressure drop occurs in the rotor stage as well.This is the reason why this turbine is more efficient as the exit pressure of the steam is lesser, and the conversion is more. The velocity drop between the fixed blades and moving blades is almost zero, and the main velocity drop occurs only in the rotor stage. * Reaction Turbine mechanism In the reaction turbine, the rotor blades themselves are arranged to form convergent nozzle Reaction Turbines. In the reaction turbine, the rotor blades themselves are arranged to form convergent nozzles. This type of turbine makes use of the reaction force produced as the steam accelerates through the nozzles formed by the rotor. Steam is directed onto the rotor by the fixed vanes of the stator.It leaves the stator as a jet that fills the entire circumference of the rotor. The steam then changes direction and increases its speed relative to the speed of the blades. A pressure drop occurs across both the stator and the rotor, with steam accelerating through the stator and decelerating through the rotor, with no net change in steam velocity across the stage but with a decrease in both pressure and temperature, reflecting the work performed in the driving of the rotor. This type of turbine makes use of the reaction force produced as the steam accelerates through the nozzles formed by the rotor. Steam is directed onto the rotor by the fixed vanes of the stator.It leaves the stator as a jet that fills the entire circumference of the rotor. The steam then changes direction and increases its speed relative to the speed of the blades. A pressure drop occurs across both the stator and the rotor, with steam accelerating through the stator and decelerating through the rotor, with no net change in steam velocity across the stage but with a decrease in both pressure and temperature, reflecting the work performed in the driving of the rotor. Principle of working * Steam turbine is one of the oldest turbo-machinery (rotating machine) deployed as a prime mover for large and continuous power generation. It converts heat energy (enthalpy) into kinetic energy (rotational energy).Whereas the generator converts Mechanical energy into Electrical energy. * Steam power generation operates on the basic thermodynamic cycle, known as Rankine Cycle. * 1 to 2: Isentropic expansion (Steam turbine) : The high pressure, high temperature steam is admitted into a steam turbine, where it expands and imparts energy to the moving blades. The pressure and temperature of steam drops as it exits the turbine. * 2 to 3: Isobaric heat rejection (Condenser) : The steam coming out of the turbine is condensed into water and feed into the boiler to again to raise superheated steam. And the cycle continues. * 3 to 4: Isentropic compression (Pump) : Water is pumped to a boiler at a higher pressure. 4 to 1: Isobaric heat supply (Boiler) : Water is converted to superheated steam through a heat transfer process. * The overall operation of the steam power plant is represented by a Heat and Mass Balance Diagram * Steam Turbines consist of a casing around the moving set of blades assembled on a rotor; that contains and controls the flow of steam. This steam is feed through an elaborate arrangement of steam inlet valves assembled over steam chest, mounted on the upper half of the casing. * The profile of the moving blades mounted on the rotor and nozzles (stationery blades) mounted on a diaphragms inside the top and bottom half casing are so designed to minimize the losses and maximize the work extraction from the steam flow. PROJECT REPORT AIM:The project aims at providing thorough information about the assembly of high pressure module of Steam Turbine of the Parli Project. It also provides a basic understanding of the working of the steam turbine, the major components which are required for its construction and the processes involved in the assembly. Components: Major Components – * Outer Casing * Inner casing * Top Half * Bottom Half * Rotor * Blades Minor Components: Support Ring | Thrust ring | U-Sealing ring | Screw Grub slotted | Angle ring | threaded ring | Stud | cap nut | Wrench | screw set | handle | Plate | screw hex | holding ring | parallel key | thrust pad | disc | Pin | Sealing ring | stud bolt | Nipple | Sleeve | plug for M24 | Technological plate | aper pin | guide column | sealing strip | shaft sealing cover | Washer | lock nut | caulking wire | square wire | lock washer | | REQUIREMENTS: DIFFERENT MACHINES USED FOR THE ASSEMBLY OF STEAM TURBINE IN BHEL, BHOPAL MACHINE NO. 20/A/67 This is a vertical boring machine. This is used for cutting inner diameter and outer diameter. It can also be used for chamfering. It is used for making many parts of rotor. MACHINE NO. 20/A/2018 This is a vertical borer. It is used for the production of the ring . This machine was used for decreasing the thickness of the ring used for the Parle project. It can also be used for performing ‘turning’ and ‘facing’ operations.This ring is used for holding the rotor during transportation to ensure its safety. It is a temporary component essential for easy and safe transportation of rotor of steam turbine. MACHINE NO. 20/A/68 This is a vertical boring and turning machine. It is used for the production of U-Sealing ring of steam turbine. This U-Sealing ring is one of the major components of the outer casing. This is of great importance because it helps to fit properly the inner casing inside the outer casing to prevent the escape of steam. MACHINE NO. 20/A/2016 This is used for the facing of the big block of iron. This big iron block can be further used for making any part of lesser dimension of steam turbine. MACHINE NO. 0/A/2087 This is a Plano milling machine. This is used for surfacing operation. It helped in the production of Parli HP Inner casing. It can also perform operations like angle cutting and face cutting. This is one of the oldest machines of BHEL, Bhopal. MACHINE NO. 20/A/2080 This is a drilling and boring machine. This is used for manufacturing dowell pin which is one of the components of steam turbine. MACHINE NO. 20/A/71 This is a shroud machine. This is used for planning of the blades of the steam turbine to make them smooth and give them an overall finish. It helps further for proper aligning of the rotor and for the smooth passage of the steam.Apart from this several other machines were used for manufacturing many other small components. These components are like breach nut, holding ring, inner ring etc. METHADOLOGY: The assembly process was as follows – 1. The basic design of the outer casing was prepared in the foundry shop and was received in the Steam Turbine Manufacturing Shop (STM) 2. Some basic machining operations were done on the outer casing. This included – shaping, planning and edge cutting. 3. The outer casing has 2 inlets and 1 outlet. Many small components such as breach nut, sealing fin and sealing rings are fit to ensure that there is no leakage of steam at the inlets as well as the outlet. 4. Barrel system is followed.In this, the outer casing is mounted vertically on a stand and all the components are fixed after that. 5. The outer casing is made as a single entity. This is because of the High pressure steam inside it. The single entity structure makes it sturdier and more resistive to breakage. 6. It is a casted structure and the primary function is to prevent the leakage of steam and to prevent any external damages to the turbine. 7. The inner casing is made in two halves – the top and the bottom half. 8. Both of them are exactly of the same shape and size. 9. HP turbine casings are of double design type, based on the steam pressure and temperature at which the turbine will operate and the application for which the turbine was designed. 10.In the steam inlet plane the inner casing is axially fixed to the outer casing at the level of the flange. The inner casing is also supported laterally by sliding keys at the flange level. At the steam inlet end, centring is achieved by keys located in the upper and lower parts. At the exhaust end, centring is accomplished by a centring bolt. 11. The outer and inner casing is made of cast steel. Pre-stressed bolts hold the upper and lower casings together at the centre line. 12. The flange design is such that it ensures complete tightness of the joint without the need for sealing materials. 13. The inner casing has grooves for fitting the blades. The size of the blades is based on the capacity of the turbine. 14.Parli Project was of 250MW. The blades are fitted separately on each half of the inner casing. 15. It was a 25 stage module. That is the number of rings of blades to fixed on the casing was 25. Initially, the blades are hammered and fixed up to a certain mark. 16. Then, some blades are kept for testing. These loose blades are required to see whether all of the blades have been fixed as required. 17. The extra portion of the two end blades in each ring is shredded from each of the loose blades partly. This is done so that the blades and the side surface of the casing are on the same level. 18. This is necessary for the two halves to fit together.There is a test called Blue Matching: Paint is applied on the surface of one of the casing. And its impression is taken on the other half. The place where there is no impression is machined and is made plane. 19. After the blades are fixed, the inner casing is sent for shroud machining. Shroud machining makes sure that blades are uniform, i. e. all the blades are on the same height vertically. 20. Then the casing is sent for other machining and finishing operations. Testing is done. The inner surface of the casing is checked for planarity. 21. Hydraulic Test : Water at pressure is filled inside the casing to see if there is any leakage. The pressure is checked periodically and if it remains the same the casing is ready. 2. The rotor also has 25 stages. The blades of the rotor are closed on both ends. They are not free. These blades are also known as rotatory blades. 23. They are fit with the help of cocking pins. The size of the blades increases from inlet towards the outlet as the volume of the steam increases. 24. After the blades are fixed on the rotor, the rotor is sent for over speed balancing. 25. Over speed Balancing: The rotor is rotated at a higher speed than the normal. 125% of the normal speed (3000rpm). The over speed balancing is done at the Banglore plant. 26. After the rotor comes back, it is aligned with the lower half of the inner casing. 27.The alignment is very important as the blades of the rotor should rotate exactly between the blades of the inner casing. 28. Also, the rotor should not vibrate along its position laterally or axially. These tests are called Axial Run out check and Radial Run out check. 29. The rotor is checked manually for any movement axially and radially. 30. The gap between the blades of the rotor and the casing has a certain tolerance level and this gap should be more than 0. 8mm 31. The top half of inner casing is then fixed on the lower half with the help of bolts and nuts. 32. The tightening is done with the help of a machine. The two halves are fixed together with the help of 20 nuts and bolts. 3. This assembly of inner casing and rotor fitted inside it is ready to be fixed into the outer casing 34. Cranes are used to lift the inner casing. A U sealing ring ensures that inner casing fits perfectly in the outer casing. Also, it would also prevent, in future, the leakage of steam, if there would be any. 35. This is the whole assembly of HP module consisting of inner casing, outer casing, the rotor and several small components. 36. This assembly is ready for dispatch. TIME LINE Dates on which major tasks took place for the assembly of High Pressure module of Steam Turbine 6 JULY Making of the holding ring. Fixing of blades of rotor. 0. mm gap to be left in the blades of the rotor for the steam to pass through. Since it is a barrel system, making proper arrangements so that rotor and inner casing can be fitted vertically inside the outer casing of the high pressure steam turbine. (Parli Module) 9 JULY Fixing of the holding ring of the high pressure turbine. It is used for locking the inner ring, which is used for rotating inner cylinder ie. Rotor. Continuation of the fixing of the blades of the rotor. 10 JULY Flenge was being made. It is an external rim for attachment to another object . Making of locking pin. Locking pin is fixed on the shaft, on which U sealing ring is fixed.If any load comes, it comes on the locking pin and not on the shaft. Hence, locking pin only breaks, shaft does not. So, it is important. 13 JULY Dry-out of holding ring. Centralization of the inner casing along with the key. 16 JULY Shroud machining of the inner casing. This is done so that all the blades are at the same level. It gives them an overall finish and helps in the smooth passage of the steam flow. 19 JULY Cleaning of the blades of the rotor. Some unwanted materials which stick to the blades during the course of time, are necessary to be removed for the proper functioning of the steam turbine. 22 JULY Checking alignment of the rotor with the shaft. With the shaft, dummy work is done.Once the centralization is done, then the rotor is put in the HP inner casing. All the distances are measured and checked. Any deficiency is removed by chamfering the same amount of material on the opposite side . 24 JULY Fitting of the diaphragm, also called the guide blade carrier. After this bolting procedure is done. 26 JULY Fitting inner casing on rotor. Tightening of all the nuts. Further testings to be done to ensure proper working. 27 JULY Assembling HP inner casing along with the rotor inside the HP outer casing. After this the U sealing ring is kept to press the inner casing. This tightly fixes the inner casing inside the outer casing. 29 JULYFinal dispatch of the product. Conclusion: The High Pressure module passed all the quality checks. It took over a month it to get ready up to this precision. Other components of Parli project were already dispatched. Whole of the turbine would be assembled on-site. The 250 MW steam turbine was one the significant projects and we were overjoyed to overlook its assembly. Other Departments Visited: CIM (Coil Induction Manufacturing) | Manufacturing insulation for coils using various materials like mica backed glass sheets etc. | Transformers | Manufacturing of transformers ( one phase and three phase) | Electric Machines | Manufacturing of motors and generators.Assembly of Stator and Rotors for Motors and generators and parts of generator | Press Shop | Sheet metal forming for different operations. Different sheet metal pressing and cutting for motors’ and generators’ stators, rotors and rims. Lamination of punchings Production of dyes for punching. | BIBLIOGRAPHY: * A practical guide to Steam Turbine Technology * Heinz P Bloch * Steam Turbine theory and practice * William Johnston Kearton * The Steam Turbine * Robert Morrison Neilson * “ Super steam…. An amazing story of Achievement” Popular Mechanics , August 1937 * Encyclopedia Britannica (1931-02-11) * A new look at Heron’s Steam Engine (1922-06-25)

Leave a Reply

Your email address will not be published. Required fields are marked *

x

Hi!
I'm Heidi!

Would you like to get a custom essay? How about receiving a customized one?

Check it out