At the heart of coal-fired electricity generation lies the steam cycle. Typically, pulverised coal is fed into a giant industrial furnace surrounded by. Abstract. In most conventional power plants the turbines are supplied with superheated steam but, during the course of its expansion, the condition of the steam enters the two-phase region and the last few low-pressure (LP) stages operate in the wet steam regime. In these power stations, steam is produced by burning some fossil fuel (e.g. coal) and then Thermal efficiency of modern thermal power stations is about 30%.
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What is the working principle of a steam power plant? - Quora
The induced draft fan assists the FD fan by drawing out combustible gases from the furnace, maintaining a slightly negative pressure in the furnace to avoid leakage of combustion products from the boiler casing. Steam turbine generator[ edit ] Main article: Turbo generator Rotor of a modern steam turbine, used in a power station The turbine generator consists of a series of steam turbines interconnected to each other and a generator on a modern steam power plant shaft.
There is usually a high-pressure turbine at one end, followed by an intermediate-pressure turbine, and finally one, two, or three low-pressure turbines, and the generator.
As steam moves modern steam power plant the system and loses pressure and thermal energy, it expands in volume, requiring increasing diameter and longer blades at each succeeding stage to extract the remaining energy. It is so heavy that it must be kept turning slowly even when shut down at 3 rpm so that the shaft will not bow even slightly and become unbalanced.
- Thermal power station - Wikipedia
This is so important that it is one of only six functions of blackout emergency power batteries on site. The other five being emergency lightingcommunicationstation alarms, generator hydrogen seal system, and turbogenerator lube oil.
The hot reheat steam is conducted to the intermediate pressure turbine, where it falls in both temperature and modern steam power plant and exits directly to the long-bladed low-pressure turbines and finally exits to the condenser. There is generally no permanent magnetthus preventing black starts.
The rotor spins in a sealed chamber cooled with hydrogen modern steam power plant, selected because it has the highest known heat transfer coefficient of any gas and for its low viscositywhich reduces windage losses.
This system requires special handling during startup, with air in the chamber first displaced by carbon dioxide before filling with hydrogen.
This ensures that a highly explosive hydrogen— oxygen environment is not created. The desired frequency affects the design of large modern steam power plant, since they are highly optimized for one particular speed. The electricity flows to a distribution yard where transformers increase the voltage for transmission to its destination.
The steam turbine-driven generators have auxiliary systems enabling them to work satisfactorily and safely. The steam turbine generator, being rotating equipment, generally has a heavy, large-diameter modern steam power plant.
The shaft therefore requires not only supports but also has to be kept in position while running.
Basic Layout and Working of a Thermal Power Plant |
To minimize the frictional resistance modern steam power plant the rotation, the shaft has a number of bearings. The bearing shells, in which the shaft rotates, are lined with a low-friction material like Babbitt metal.
Oil lubrication is provided to further reduce the friction between shaft and bearing surface and to limit the heat generated. Stack gas path and cleanup[ edit ] See also: Flue-gas emissions from fossil-fuel combustion and Flue-gas desulfurization As the combustion flue gas modern steam power plant the boiler it is routed through a rotating flat basket of metal mesh which picks up heat and returns it to incoming fresh air as the basket rotates.
Basic Layout and Working of a Thermal Power Plant
This is called the air preheater. The gas exiting the boiler is laden with fly ashwhich are tiny spherical ash particles. The flue gas contains nitrogen modern steam power plant with combustion products carbon dioxidesulfur dioxideand nitrogen oxides.
The fly ash is removed by fabric bag filters in baghouses or electrostatic precipitators. Once removed, the fly ash modern steam power plant can sometimes be used in the manufacturing of concrete.
This cleaning up of flue gases, however, only occurs in plants that are fitted with the appropriate technology.