Heat Recovery Steam Generator

Thursday, November 20, 2008

A heat recovery steam generator is a heat exchanger which recovers heat from a hot gas stream. It produces steam that can be used to drive a steam turbine. A common application for a heat recovery steam generator is in a combined-cycle power station, where hot exhaust from a gas turbine is fed to a heat recovery steam generator to generate steam which in turn drives a steam turbine. This combination produces electricity more efficiently than either the gas turbine or steam turbine alone.

Another application for a heat recovery steam generator is in diesel engine combined cycle power plants, where hot exhaust from a diesel engine is fed to a heat recovery steam generator to generate steam which in turn drives a steam turbine. The HRSG is also an important component in cogeneration plants. Cogeneration plants typically have a higher overall efficiency in comparison to a combined cycle plant. This is due to the loss of energy associated with the steam turbine.

A heat recovery steam generator consists of three major components. They are the Evaporator, Superheater, and Economizer. The different components are put together to meet the operating requirements of the unit.