Essentials of steam turbine design and analysis aiche. A steam turbine is a device that extracts thermal energy from pressurized steam and uses it to do mechanical work on a rotating output shaft. But this loss can be minimized through some process. Steam turbine gets heat energy in the form of superheated steam from steam generator. While these technologies have not caused any large losses, the inherent. Because power is the rate of energy utilization, efficiency can also be expressed as a power ratio. Impulse and reaction principles, compounding, velocity diagrams for. It will be necessary to obtain the following operating data from the field. The steam turbine operates under high steam pressures, and has a number of moving parts that move at extremely high velocities. The sst800 is a single casing steam turbine with center steam admission and reverse steam flow inner casing, designed for a direct coupled generator or mechanical drive. The k 200 the k 200 1 steam turbine s rated thermal efficiency i s 44.
The siemens sst600 is the right answer to meet all of these different needs. A technical seminar report on working of steam turbines submitted in partial fulfilment of requirements for the degree of bachelor of technology in mechanical engineering submitted by. Types of steam turbine, types of turbine, steam turbine efficiency, small steam turbine, steam turbine basics, a steam turbine is a device that extracts thermal energy. Pdf efficiency assessment of condensing steam turbine.
The rankine cycle is a practical cycle and most steam power plants are based on it. In general, a steam turbine is a rotary heat engine that converts thermal energy contained in the steam to mechanical energy or to electrical energy. Steam turbine maintenance is of high importance to keep the steam turbines efficiency high and to conform to safety standards to avoid any unforeseen dangers. Practically 100% gross efficiency is not possible for any turbine. Steam turbine is the widely use as a prime mover in power plants, refineries, petrochemical plants, food processing plants, power plants etc. It produces only small net power outputs for the plant size because dry saturated steam is used at inlet to the turbine. Ger3706d steam turbines for industrial applications. The condensing steam turbine is a conventional steam turbine in which the steam exiting the turbine exhaust is condensed to provide the maximum energy capture. In this system,the steams ability to work may be slightly increased by reheating the steam during its passing through the turbine. This is the type of steam turbine that will be used in a bottoming cycle chp plant in which waste heat or energy from an industrial process is used to raise steam to generate electricity. Pdf power plant lecture notes chapter2 steam power. Because the turbine generates rotary motion, it is particularly suited to driving electrical generators about 90% of all electricity generation in the united states. Unlike with reciprocating engines, for instance, compression, heating and expansion are. The k 200 the k 200 1 steam turbines rated thermal efficiency i s 44.
Maintenance and overhaul of steam turbines wgp42 05. Power plant lecture notes chapter2 steam power plant cycles. Its modern manifestation was invented by charles parsons in 1884 the steam turbine is a form of heat engine that derives much of its improvement in thermodynamic efficiency from the use of multiple stages in the expansion of the steam, which results. Steam turbines are complex equipment, with a long lifecycle. The efficiency of any machine is defined as the ratio between the output energy and the input energy. A steam turbine is a mechanical device that extracts thermal energy from pressurized steam and transforms it into mechanical work. Combined heat and power technology fact sheets series. Since then turbines based on these principles have evolved in parallel and in fact merged to some degree. In case of turbines with cooling water preheating and lowpressure lp bypass, prior to supplying steam the regeneration and dumping systems have to be. In this article, we see about the impulse turbine and reaction turbineprinciple, working and difference. The gas turbine outlet temperature is maintained at the level of t4a 630 c. Process improvements made over time typically lead to a juncture when the turbine becomes the bottleneck and needs a cost57 efficiency improvements on large mechanical drive steam turbines by nathan t. Inlet steam conditions are 1250 psig, 900 deg turbine mechanical efficiency 97%. When purchasing a steam turbine, it is good practice to require all bidders to provide values of.
Steam turbine, energy performance, efficiency assessment, heat balance 1 introduction. Practical steam turbine performance calculations using flex lives steam flex routine or by manual methods a steam turbine s power andor efficiency can be quickly and accurately calculated using flexwares steam flex steam properties program. In its simplest form, a steam turbine consist of a boiler steam generator, turbine, condenser, feed pump and a variety of auxiliary devices. Directly coupled steam turbines in combinedcycle applications must provide the performance and flexibility required for integration steam turbines for industrial applications ge power systems ger3706d 3 geared turbine generator sets. When turbine works, some factors have reduced the output of the turbine, known as the losses in steam turbine or internal loss in the turbine. There are some energy losses in the bearings and governing mechanisms which can be reduced by improving the lubrication system. This is expanded to 3 bar with an isentropic efficiency of 0.
Mechanical drive steam turbines mechanical drive steam turbines figure 6 range from 3 to 60 mw 80,000 bhp, with speeds of up to 16,000 rpm, and are either condensing or noncondensing types. This will increase its expansion ratio and steam has become wet condition at the end of. Mhi performed the major inspection in october 2011 in order to check the mechanical condition, and confirmed that the hot parts and. The first steam turbine used for power generation was invented in 1884. The steam turbine generators used today produce approximately 85%.
Thermal efficiency of the cycle can be increased either by reducing the condenser pressure or by. Efficiency of steam turbines mechanical engineering. Impulse turbine and reaction turbineprinciple, working. The steam turbine is a turbine in which the potential energy of heated and compressed steam produced in a special device, a steam generator, or steam of natural origin for example, from geothermal springs is converted into kinetic energy when the steam expands in the turbine blade cascades and then into mechanical work on the rotating shaft. Steam first enters into the turbine at superheated state. Outlet steam conditions for process are 165 the cycle includes a direct contact psia. It is impractical to compress wet steam because the water content separates out.
Steam turbine types steam turbine types based on blade geometry and energy conversion process are. While the functions are the same for all steam turbines, the designs are sufficiently. The highly customized turbine provides for an outstanding efficiency, fast startup times and high reliability and availability. Since a steam turbine is costly equipment a decision must be taken regarding replacing or. The turbine is operational since 1968, therefore an efficiency assessment can highlight its present technical condition. This manual does not for designing steam turbine and the related parts.
Since the turbines are adequately insulated the surface heat loss by convection and radiation is small. It is also well suited where highefficiency steam turbines are demanded. Operation and maintenance schedule of a steam turbine. Now steams pressure and temperature is improved by efficiency of rankine cycle. Steam turbine thermal energy mechanical energy gas turbine chemical energy mechanical energy. Types of steam turbine an overview sciencedirect topics. Mechanical governors are sensitive to ambient conditions and have components. Unlike with reciprocating engines, for instance, compression, heating and expansion are continuous and. Calculate turbine efficiency improve steam turbine. The methodology of the gas turbine efficiency calculation. Steam turbines are one of the most versatile and oldest prime mover technologies still in general production used to drive a generator or mechanical machinery. Determine inlet properties using the steam property calculator, properties are determined using inlet pressure and the selected second parameter temperature, specific enthalpy, specific en. All outlet steam is used by the process, feedwater heater there are no closed.
The efficiency of any turbine or engine can be defined as its ability to convert the input energy into useful output energy which is expressed in the form of the following equation efficiency. Faculty of mechanical engineering smex1009thermal engineering unit iii unit iii steam nozzles and turbines flow of steam through nozzles, shapes of nozzles, effect of friction, critical pressure ratio,supersaturated flow. Mechanical fluid dynamic efficiency section efficiencies in terms of energy conversion. The turbine soon dominated largescale electricity generation with its compact size, efficient use of steam, and reliability, resulting from its few moving parts. The isentropic efficiency cannot be determined exactly, but it can be estimated fairly accurately using empirical correlations based on historical industry experience, which are usually available from steam turbine vendors. Steam turbine losses in steam turbine mechanicaltutorial. Complete steam turbine compressor packages as well as separate mechanical drive steam turbines, which meet api requirements, are available. Its efficiency was also boosted by using steam supplied by water tube boilers which had been developed for naval vessels and are described in section steam applied to transport. Technology improvements driven by need of higher efficiency led to a new generation of steam turbines. Turbine energy efficiency has an significant impact on overall steam power plant efficiency. An ideal turbine with 100% efficiency is the one which converts all its input energy into output work without dissipating energy in the form of heat or any other form. Prior to supplying steam to the turbine, the steam supply pipelines have to be drained and heated up.
Practical steam turbine performance calculations using flex lives steam flex routine or by manual methods a steam turbines power andor efficiency can be quickly and accurately calculated using flexwares steam flex steam properties program. What is steam turbine description and characteristics. A steam turbine takes steam at 70 bar and 500oc and expands it to 0. The difference between gas turbine and steam turbine can be done on the basis of components, space for installation, mass per kw produced, installation and running cost efficiency, control with the changing load condition, starting, efficiency and dependency on water supply. These losses are directly affected by the turbines output as well as its efficiency.
1416 672 1310 864 458 720 558 614 268 1078 662 853 424 1156 807 296 586 1418 226 793 1502 923 5 968 1330 158 449 1198 622 1084 620 1038 28 56 182 1354 461 1420 1342 340 708 1259 1409