Engineering

Casing  Based on high inlet pressure and temperature the casing construction shall be either single or double shell type. The double shell construction prevents the steam contact to the outer casing joint and it will be used in case of high inlet steam conditions. Single casing has all its stages in the one casing and all are connected to a common drive shaft. Steam expansion, controlled / uncontrolled extraction provision within casing. Double casing turbines have the exhaust steam circulating in the annular space between the casings as in case of high steam inlet condition and also the steam within the space will be taken into controlled / uncontrolled extraction for process / feedwater heating if required. Double shell casing Single shell casing The parts of the turbine that control the position of the rotating components in relation to the fixed components are supported and located precisely at shaft height, they move independently of each other. For smaller turbine, bearing ho...

Compounding of steam Turbine Compounding method in which energy from the steam is extracted in several stages rather than a single stage in a turbine. In all turbines, the rotating blade velocity is proportional to the steam velocity passing over the blade. If the steam is expanded only in a single stage from the boiler pressure to the exhaust pressure, its velocity must be extremely high. A  compounded steam turbine has multiple stages,  i.e., it has more than one set of nozzles and rotors, in series, keyed to the shaft or fixed to the casing, so that either the steam pressure or the jet velocity is absorbed by the turbine in several stages Compounding will be done mostly on Impulse type Turbine and for Reaction turbine the same is not required (except few cases of severe application, only pressure compounding can be done but it is different from the compounding arrangement discussed below)   Velocity Compounding   A velocity-compounded impulse stage...

Steam turbine is a type of turbomachine which is an assembly of nozzles and blades. It converts a part of the energy of high temperature and high-pressure steam (Enthalpy of steam into Kinetic in nozzle) into mechanical energy (or shaft work). The operation of steam turbine completely depends on the dynamic action of the steam expanding in nozzles.  The steam turbines are used for the generation of electricity in steam power plants varying from 1 MW to 1500 MW capacity. These are also used for marine propulsion. The steam turbines operate at very high speed (up to about 40,000 rpm) and are able to give efficiency about 40% which is higher than the other power producing devices. Because of its ability to develop tremendous power within a comparatively small space, the steam turbine has superseded all other Prime Movers , except hydraulic turbines, for generating large amounts of electricity and for providing propulsive power for large, high-speed ships. Today, units capable of gene...