steam turbine casing manufacture

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Transcript of steam turbine casing manufacture

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BHARAT HEAVY ELECTRICALS LIMITEDPresentation By:-Omkar manav 10H51A0395CMRCET COLLEGE

Industrial Training

Flow of the presentationOver viewVision, Mission & ValuesBhel productsSector detailsFinancial AnalysisBhel ramachandrapuramSteam turbine classificationsTc &gt producton activitiesMachine shopMachining of steam turbine casing

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Overview of BHELBHEL was established in 1964.BHEL is one of the only 7 Public Sector Undertakings (PSUs) of India clubbed under the esteemed 'Maharatna'status.On 1st February 2013, theGovernment of IndiagrantedMaharatnastatus toBHEL.BHEL has a share of 59% in Indias total installed generating capacity contributing 69% (approx.) to the total power generated from utility sets (excluding non-conventional capacity) as of March 31, 2012.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 (Railway), Renewable Energy, Oil & Gas and defence.BHEL has 15 manufacturing divisions, two repair units, four regional offices, eight service centers and 15 regional centers and currently operate at more than 150 project sites across India and abroad.

Main Manufacturing UnitsBHEL Bhopal (Madhya Pradesh )BHEL Ramachandrapuram, Hyderabad (Andhra Pradesh)Transformer Plant, BHEL Jhansi(Uttar Pradesh)High Pressure Boiler Plant and Seamless Steel Tube Plant, Tiruchirapalli(Tamil Nadu) Boiler Auxiliaries Plant, Ranipet (Tamil Nadu)ElectronicsDivision and Electro Porcelain Division, Bangalore(KarnatakaJagdishpur (Uttar Pradesh)Rudrapur (Uttrakhand)Industrial ValvesPlant, Goindwal (Punjab)BHEL Ranipur, Haridwar (Uttarakhand) Bharat Heavy Plates and Vessels Limited(Vizag)

SERVICE GROUPS OF BHELSteam turbines, compressors and gas turbinesCommon servicesHeat exchangers and pulverizesPumpsElectrical machinesQuality servicesSwitch gearsFinance and accountsTownship administrationProject managerMaterial management.

Product Range

ProductsBoiler(stream generator) Gas GeneratorHydro GeneratorSteam turbineGas turbineHydro turbineTransportation EquipmentsTraction MachinesTransformerSwitchgearOil field equipments OFEBoiler drumWater wall panelWind millValve Electro-static PrecipitatorsR & D products

Generator:

Operating Principle: The rotor is mounted on a shaft driven by mechanical prime mover.A field winding (rotating ) carries a DC current to produce a constant magnetic field. An AC voltage is induced in the 3-phase stator winding (stationary) to produce electrical Power. The electrical frequency of the 3-phase output depends upon the mechanical speed and the number of poles.3-phases output is directly connected to load.

Steam Turbine

Asteamturbineis a device that extractsthermal energyfrom pressurizedsteamand uses it to domechanical workon a rotating output shaft. The steam turbine is a form ofheat enginethat derives much of its improvement in thermodynamic efficiencyfrom the use of multiple stages in the expansion of the steam, which results in a closer approach to the ideal reversible expansion process.

PulverizerThe coal is put in the boiler after pulverization. For this pulverizer is used.A pulverizer is a device for grinding coal for combustion in a furnace in a power plant. Types of Pulverizers: i)Ball and Tube Mill ii) Ring and Ball

BoilerBoiler is an enclosed vessel in which water is heated and circulated until the water is turned in to steam at the required pressure. Coal is burned inside the combustion chamber of boiler. The products of combustion are nothing but gases. These gases which are at high temperature vaporize the water inside the boiler to steam.Boilers are classified as:Fire tube boilersWater tube boilers Superheater Reheater

Condenser

Steam after rotating steam turbine comes to condenser. Condenser refers here to the shell and tube heat exchanger (or surface condenser) installed at the outlet of every steam turbine in Thermal power stations of utility companies.The purpose is to condense the outlet (or exhaust) steam from steam turbine to obtain maximum efficiency and also to get the condensed steam in the form of pure water, otherwise known as condensate, back to steam generator or (boiler) as boiler feed water. Condensers are classified as: i)Jet condensers or contact condensers, ii)Surface condensers.

Cooling Towers

The condensate (water) formed in the condenser after condensation is initially at high temperature. This hot water is passed to cooling towers. It is a tower- or building-like device in which atmospheric air (the heat receiver) circulates in direct or indirect contact with warmer water (the heat source) and the water is thereby cooled.Types Of Cooling Tower-Wet cooling towerDry cooling tower

Economizer Flue gases coming out of the boiler carry lot of heat. Function of economizer is to recover some of the heat from the heat carried away in the flue gases up the chimney and utilize for heating the feed water to the boiler. It is placed in the passage of flue gases in between the exit from the boiler and the entry to the chimney. The use of economizer results in saving in coal consumption, increase in steaming rate and high boiler efficiency but needs extra investment and increase in maintenance costs and floor area required for the plant.

Electrostatic Precipitator

It is a device which removes dust or other finely divided particles from flue gases by charging the particles inductively with an electric field, then attracting them to highly charged collector plates.

Some of the usual applications are: (1) Removal of dirt from flue gases in steam plants (2) Cleaning of air to remove fungi and bacteria in establishments producing antibiotics and other drugs, and in operating rooms (3) Cleaning of air in ventilation and air conditioning systems (4) Removal of oil mists in machine shops and acid mists in chemical process plants (5) Cleaning of blast furnace gases (6) Recovery of valuable materials such as oxides of copper, lead, and tin

Alternator

An alternator is an electromechanical device that converts mechanical energy to alternating current electrical energy. Most alternators use a rotating magnetic field. Different geometries - such as a linear alternator for use with sterling engines - are also occasionally used. In principle, any AC generator can be called an alternator, but usually the word refers to small rotating machines driven by automotive and other internal combustion engines.

Transformers

It is a device that transfers electric energy from one alternating-current circuit to one or more other circuits, either increasing (stepping up) or reducing (stepping down) the voltage. Uses for transformers include reducing the line voltage to operate low-voltage devices (doorbells or toy electric trains) and raising the voltage from electric generators so that electric power can be transmitted over long distances. Transformers act through electromagnetic induction; current in the primary coil induces current in the secondary coil. The secondary voltage is calculated by multiplying the primary voltage by the ratio of the number of turns in the secondary coil to that in the primary.

Sector DetailsPower transmission sector, high voltage direct current (HVDC) technology. It manufactures a vast range of transformers, instrument transformers, thyristor valves, and associated control equipment.Industrial equipment sector, BHEL supplies a wide variety of electrical, electronic and mechanical equipment to a host of industries, viz. fertilizers, petrochemicals, refineries, coal, steel etc.Oil and Gas, BHEL has designed, manufactured and serviced various types of on-shore deep drilling rigs, super-deep drilling rigs, mobile rigs and desert rigs with matching draw works and hoisting equipment Telecommunication area BHEL has manufactured electronic private automatic branch exchanges (PABXs) and rural automatic exchanges (RAXs) for IndiaNon-conventional energy, BHEL has contributed by way of manufacturing equipment like solar water heating systems, solar photo-voltaic systems and wind electric generators

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Transportation sector, over 66% of the Indian Railways, is equipped with traction equipment by BHEL. Kolkata Metro is equipped with BHEL drives and controls.

Other products in the sector include traction generators/ alternators, transformers, sub-station equipment, vacuum circuit breakers, locomotive bogies, smoothing tractors, exciters, converters, inverters,

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Technological StrategyResearch and Development StrategyWork-Culture and PhilosophyVendor DevelopmentQuality StrategyManufacturing StrategyFlexible Manufacturing TechnologyShare Point Portal Server Other strategies

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BHEL:Financials

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BHEL Ramachandrapuram UnitBHEL Ramachandrapuram Unit has acquired considerable experience in the design and manufacture of various important types of pumps required for the thermal power plants

designed and manufactured for 60 MW, 110 MW and 210 MW under technical collaboration with M/s. Sigma Lutin of Czechoslovakia.

In order to meet the requirements of higher efficiency pumps for 210 MW units and large capacity pumps for 500 MW units, collaboration was entered in 1980 with M/s. Wier Pumps Limited, U.K., who are acknowledged as one of the leading manufacturers of pumps in the world.

In 2007, BHEL Hyderabad has entered into collaboration with M/s. Mitsubishi Heavy Industries, Japan to manufacture pumps for super-critical thermal power plants up to 1000 MW

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PRODUCT AND PROCESSESTurbine & Compressors shop.Steam Turbines Compressors.Gas Turbines Compressors.Turbo Generators.Steam Generators.Gas Generators.Switch Gears.Ferrous Foundry.Non-Ferrous Foundry.Heat Exchangers.Tool Room.Heat Treatment.Pattern shop.Spares Manufacturing.Coal pulverizes.Pumps.

Steam turbines manufacturedSTEAM TURBINES MANUFACTURED IN BHEL HYD Various types of SIEMENS model turbines are manufactured at BHEL Hyderabad according to the requirement of any customer to suit his boiler steam parameters. They are: Type Turbine G - Back pressure type EG - Extraction back pressure type EHG - Extraction back pressure type with high inlet parameters HG - Back pressure type with high inlet parameters K - Condensing type EK - Extraction condensing type WK - Double flow condensing type EMG - Electrochemically machined rotor of back pressure type EHNK - Extraction condensing with inlet parameters and high speed type NK - Straight condensing with high speed type

Catogaries in steam turbine

Industrial steam turbine are categorized into different series like -2 series -3 series -4 series

2 SERIES TURBINESstandard type and have been designed for the best efficiency for range parameters.Designs being the standard further based on then steam flow quantities size of the turbine is selected in these series of turbines the fixed blade grooves are machined directly in the outer casing and guide blades are inserted

Different sizes of -2 types of turbines are: G250-2 EK/K 600-2 G300-2 EK/K 800-2 G400-2 EK/K 1000-2 G500-2 EK/K 1100-2 G800-2 EK/K 1400-2 G stands for back pressure turbine K stands for condensing turbines E stands for controlled extraction

-3 SERIES TURBINE:

Based on customers requirements and steps involved in design, the turbine is divided into different sections: inlet section, transition, exhaust or condensing sectionthe size of the section is geometrically graded in the ratio to 1.25 to form different sizes of section

-4 SERIES TURBINES:

These types of series are called as centre admission steam turbines with counter flowrange of power, between 30MW to 150 MWThe steam reverses the direction on the reaching the end of inner casing to flow around inner casing and expands towards the rear end of the turbineThis process of reverse flow of steam helps in control the axial thrust to a large extent.These turbines are directly coupled to the generator. The valve blocks in these turbines are separate

TC&GT PRODUCTION ACTIVITIES

Machine shops Bay 0Maintenance and service dept / Heavy duty CNC machines / Steam turbine 150 MW Assembly shopBay 1Heavy duty CNC machines / Gas turbine rotor AssemblyBay 2Heavy machine shop withHeavy duty CNC and conventional machinesBay 3Blade shopBay 4Heavy duty CNC Lathe machines and steam turbine rotor assembly

Bay 5Impeller shop / Light machine shop / Gas turbine wheel Assembly Bay 6 Medium machine shopBay 7Gas turbine machine shop / Steam turbine Regulation Assembly

Bay 0Maintenance and service dept / Heavy duty CNC machines / Steam turbine 150 MW Assembly shop

QiQihar CNC horizontal boring machines 2 nosTacchi CNC lathes 2 nos

QiQihar CNC horizontal boring machines 2 nos

Tacchi CNC lathes 2 nos

Bay 1Heavy duty CNC machines / Gas turbine rotor Assembly

INNSE Horizontal CNC machine :Mario Carnaghi Gantry type machine :Gas turbine Rotor Balancing machine Tacchi heavy duty CNC lathe:

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INNSE Horizontal CNC machine :

This machine is provided with Sinumerik 840C CNC system

Mario Carnaghi Gantry type machine :

Rough machining of heavy casings of 120 MW design is carried out on this machine. Both top and bottom casings can be placed side by side on the table with the parting plane up for machining.

Rough machining of heavy casings of 120 MW design is carried out on this machine. Both top and bottom casings can be placed side by side on the table with the parting plane up for machining.

Gas turbine Rotor Balancing machine :

The rotors are balanced individually and as a unit rotor also for its unbalance before lowering into the gas Gas turbine Rotor Balancing machine :Machining of heavy rotors, drilling, reaming of Coupling holes on turbine rotor and load coupling of gas turbine also carried out in this shop

Tacchi heavy duty CNC lathe:

Tacchi heavy duty CNC lathe:

Machining of heavy duty rotors are carried out on this machine. The max weight carrying capacity of the machine is 80 T. This machine is provided with Sinumerik 840 D CNC system. Gas turbines of Fr5, Fr6 and Fr9 flange to flange assembly is carried out here.

Bay 2Heavy machine shop withHeavy duty CNC and conventional machines

withHeavy duty CNC and conventional machinesHeavy machine shop

Machining of peripheral details and grinding of parting planes of casings are carried put in this shop. The important machines in this bay are Plano grinding machine etc Radial drilling machines etc

Heavy duty CNC machines: Mitsubishi Horizontal boring machine :DorriesVeritical CNC lathe:Skoda Horizontal boring machine:Skoda Vertical CNC lathe:

Mitsubishi Horizontal boring machine :

Fir tree blade root machining on steam turbine rotor is carried out on this machineFanuc 9 CNC system.

Skoda Horizontal boring machineMachining of combustion bores on gas turbine casings, peripheral details on steam turbine casings are carried out on this machine

Skoda Vertical CNC lathe:

Finishing machining casings including guide blade grooves are carried out in vertical position on this lathe. The machine is provided with 840-C CNC system.

Bay 4Heavy duty CNC Lathe machines and steam turbine rotor assemblyHeavy duty CNC Lathe machines and steam turbine rotor assembly

Functions of baySteam Turbine rotor Assembly :Sealing fins drawing machine LP drilling Machine :A-Wheel drilling Machine (Impulse blade drilling machine

CASING SHELL OR CYLINDER

ASTM A 356 Grade 1 for cast carbon steelNodular Cast Iron GGG40The reason is that cast carbon steel is weld repairable(LP turbine inner casing rings,)Casing Materials

1-2 cr mo steels low temperature steamCast 9 Cr 1 Mo- V Nb alloys9-12-cr martensite /ferrite steel

Properties applications as they offer usefulcombination of high temperature mechanicalproperties and corrosion/oxidation resistance

Casing boltsBolting materialpropertiesNimonic 80A Inconel 740Allvac 718 plus (super alloy )

High resistance to stress relaxationCreep relaxation behaviouroffering excellent mechanical properties, increased temperature capability, good fabricability and moderate cost

Unstable states arising during start-ups, shutdowns and load changes give rise to unsteady temperature distribution with time in steam turbine innercasing (HP/IP), which results in non-uniform strain and stress distribution

The rapid increase of temperature during starts-ups, especially, causes susceptible to failure and reduction of expected life for steam turbine components. Thus accurate knowledge of thermal stresses is required for the integrity and lifetime assessment for the turbine

MACHINING SEQUENCE UNDERGONE BY STEAM TURBINE -3 CASING:

Casing

Lower halfUpper half

1)Marking on both lower half and upper half of casing with machine allowanceOr Punching on cnc machine during machining with allowances2)Skin cut on connecting flang face of lower half by positioning the parting plane downwards this process is repeated for upper half also (INNSE MACHINE )3)Now the loading the lower half in vertical position by the help of bearing and clamps 4)Repeat the process for upper half as well5)Parting plane present in both upper half and lower half are rough milled and then are followed by finish milling by positioning the job in vertically with inner part facing the milling cutter (INNSE)

Parting plane in lower and upper half are drilled and threaded as per the drawing provided While providing reses the job is still in vertical position

Eccentric pin holes packets machining followed by pin holes drilling and finish boring is operation is done only in lower half 10)Drain holes drilling and slots milling done only in lower half11)Guide blade carriers shoulders machining only in lower half 12)Guide blade carriers guides are done rough milling 13)Steam chest area machining is done only in upper half 14)Job position is changed and clamped in vertical positonie the casing is placed backside towards the spindle of machine

Now the casing is moved to next machine for further operation

( TOS KURIM)

Parting plane holes done backcounter boring in both lower and upper half Eccentric pin holes are back counter bored and holes are positioned this is done only in lower half18)Steam valve spindle boring drilling and finish boring is done only in upper half 19)Resting paws are milled in upper half20)Job position is changed and loaded as combined part on an hydraulic box and tightened with studs and capnut for stiffness

21)combined position is loaded on machine table 22)Job in combined position is performed with finish boring of guide blade carriers and connecting flange 23)Connecting flange holes are drilled and provided with threading 24)Now the combined part is rotated by 18025)Front gland is rough milled 26)The combined job is sent for inspection27)After inspecting the job is dismantled 28)Now the job is loaded in vertical position with parting plane facing the spindle of machine29)Rough and finish machining of balance piston gland is done by vertical attachment30)Job is inspected 31)Stop valve body finish boaring in upper half 32)Diffuser bore finishing bores finish boring and inspection

Machining for peripheral holes

a)Peripherial holes radial drilling both inside and outside of casing b)Flange fixing holes c)Wall temperature measurement holesd)Thermoelement holese)Pressure test holes (hydraulic pressure tasting holes)f)Tapper pin holesg)Guide pinning holes

h)Focing off screw holesi)Main steam inlet flange holes34)Blue matching both the halves to ensure parting plane contact area by 90% to 100%35)If not performing a) scraping b)deburing36)Hydraulic pressure testing37) sent for assembly