A steam turbine is a mechanical device that extracts thermal energy from pressurized steam and transforms it into mechanical work. Consider steam turbine drives for rotating equipment. Turbine rolling procedure free download as pdf file. Schematic diagram of 200 mw unit 8 construction of the steam generator is carried out in two distinct bodies, symmetrical with the axis of the group, operating in parallel to the k2001 steam turbine. Power regulation adjusts the operation of the steam turbine load current, i. Further, once the turbine has been split into separate sections, additional efficiency gains can be made by reheating the steam when it exits the highpressure turbine where it will have cooled and before it enters the intermediatepressure turbine. Steam turbine performance 3 4 2 1 46 45 44 43 42 41 43 42 41 40 39 % % 1. Principles of operation of a steam turbinewhen high temperature steam passes through a steam turbine. Aug 19, 20 a condenser installed at the exhaust or low pressure end of the turbine receives and condenses the steam prior to it being pumped back to the boiler. The drop in pressure across the turbine will cause it to rotate. Dear all, why ip rolling is preferred than hip hp rolling. Thermal efficiency of a steam turbine is usually higher than that of a reciprocating engine. Our steam turbine portfolio spans across all fuels, from gas and coal to nuclear applications from 100. In noncondensing turbines or backpressure turbines, steam exhausts at a pressure greater than.
Steamturbine principles and practice by croft, terrell, 1880publication date 1923 topics steamturbines publisher new york. Now charge the turbine inlet valve for line warm up by venting out the steam via turbine start up vent. D0 is the main steam flow before the variable condition. Over the last 100 years, ge has manufactured and installed a worldwide fleet of steam turbines.
Steam turbines startups 1 principles of steam turbines startups. The purpose of this pilot valve was to maintain a rolling steam supply to the cruising turbine sufficient to turn it at around 400 r. As turbine exhaust is connected to a condenser which is operated below atm pressure so there are chances of air ingres or va. The steam turbine rotor is the spinning component that has wheels and blades attached to it. Pdf portable document format pdf 68 care and maintenance. Steam turbine a steam turbine is a mechanical device that extracts thermal energy from pressurized steam, and converts it into useful mechanical work. Steam turbine governing is the procedure of controlling the flow rate of steam to a steam turbine so as to maintain its speed of rotation as constant. Since the steam turbine is a rotary heat engine, it is particularly suited to be used to drive an electrical generator. Very high powertoweight ratio, compared to reciprocating engines. Steam process in steam turbine steam entrance to turbine through governor valv e to control steam capacity and therefore to control turbine speed. The variation in load during the operation of a steam turbine can have a significant impact on its performance.
Journal bearings are at each end of each rotor to support the weight of the rotor. The blade is the component that extracts energy from the steam. Impulse turbines an impulse turbine uses the impact force of the steam jet on the blades to turn the shaft. Efficiency will depend on turbine size or rotor diameter, blade geometries, speed, extreme condition of steam and other losses. Three basic phases can be distinguished in the process of steam turbine unit start. The main use for steam turbines is in electricity generation in the 1990s about 90% of the worlds electric production was by use of steam turbines however the recent widespread application of large gas turbine units and typical combined cycle power plants has resulted in reduction of this percentage to the 80% regime for steam turbines. Scribd is the worlds largest social reading and publishing site. Steam turbine operating conditions the steam cycle the essential elements of the steam cycle include the boiler or steam generator, turbines, generator and condenser.
Steam turbine thermal modeling for improved transient. A presentation on turbine rolling atrs final 2 free download as powerpoint presentation. For understanding the gland sealing system first we have to understand why it is required so there are two main reason. Two basic types of steam turbine designs are available. A selfcontained lubrication system oft en used to grease inaccessible places. The principles of correct conducting startups have been developed over the longterm operation of steam turbines and contain experience of turbine designers, constructors and operators. Latest technologies and future prospects for a new steam turbine. Aug 01, 2012 turbine generator maintenance 180,068 views.
Pdf simulation of speed steam turbine control system. This thesis addresses the thermal modeling of steam turbines. A presentation on turbine rolling atrs final 2 electric. Method for starting a steam turbine alstom technology ltd. Schofield ge company schenectady, ny introduction the need to provide stateoftheart products for a diverse and everchanging market is the chal lenge facing steam turbinegenerator manufactur ers in the 90s. In case of turbines with cooling water preheating and lowpressure lp bypass, prior to supplying steam the regeneration and dumping systems have to be.
One thrust bearing typically is provided for the entire steam turbine to maintain the axial position of the rotor. Appendix b glossary of steam turbine terms antifriction bearing. Steam has one great advantage over waterit expands in volume with tremendous velocity. In the turbine governor the target rotational speed 3000 rpm is set as well as runup rate. Steam turbine portfolio overview digital asset management. Steam turbine, watersteam chemistry, stress corrosion cracking. Ger3705 ge steam turbine design philosophy and technology. One is an impulse design in which the rotor turns as a result of the force of steam on the blades. This service generally calls for a backpressure noncondensing steam turbine. Nevertheless modern steam turbines are very efficient and operate with internal efficiencies within the range of 80 percent to 90 percent depending upon the steam conditions. Following figures show steam process in steam turbine.
Next hp and ip stop valves can be opened, with control valves closed. Steam for turbine is provided by pp330140p55 type steam generator, a oncethrough coalfired boiler 8. Steam turbine operating conditions, chemistry of condensates. There are two classical types of turbine stage designs.
This is a common feature of the steam turbines used in coalfired power plants. The water and steam run through a continuous cycl e of water boiled into steam, used in the engine, condensed back to water, and then pumped back into the boiler for reuse, a cycle first studied scientifically by the. The starting process of a steam turbine can be divided into three phases. Intermediatepressure turbine an overview sciencedirect. The method of claim 1 wherein the prewarming includes filling the steam turbine with the steam. Prior to supplying steam to the turbine, the steam supply pipelines have to be drained and heated up. Our steam turbines equip 41% of the worlds combinedcycle plants, 30% of fossil power plants, and 50% of the worlds nuclear power plants. All controls of hp bypass are on manual mode and all valves are closed. New procedure speeds cold start, protects turbine power. How does the steam turbine gland sealing system work. Gt load 50mw for cold start up conditions gt load 65 mw for warmhot start up st on turning gear minimum 6 hrs one cep in service one cw pump in service st turning gear operation f. An antifriction bearing is a bearing that utilizes rolling elements between the stationary and rotating assemblies.
Powerpoint presentation on steam turbine powerpoint. A simplified steam cycle7, in this case with a drumtype boiler, is shown schematically in figure 1. Steam consumption of steam turbine is depending to required output power and efficiency of the turbine. Consider steam turbine drives for rotating equipment steam turbines are well suited as prime movers for driving boiler feedwater pumps, forced or induceddraft fans, blowers, air compressors, and other rotating equipment. Sliding pressure optimization method for steam turbine with. In an extracting type turbine, steam is released from variousin an extracting type turbine, steam is released from various stages of the turbine, and used for industrial process needs or sentstages of the turbine, and used for industrial process needs or sent to boiler feed water heater to. Mar 09, 2017 rolling means getting the steam turbine to rotate. Because the turbine generates rotary motion, it is particularly suited to driving electrical generators about 90% of all electricity generation in the united states 1996 is by use of steam turbines 1 wiser.
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