A heat recovery steam generator or HRSG is an energy recovery heat exchanger that recovers heat from a hot gas stream, usually coming from gas turbine or engines. It produces steam that can be used in a process (cogeneration) or used to drive a steam turbine (combined cycle).
HRSGs consist of four major components: the economizer, evaporator, superheater and water preheater. The different components are put together to meet the operating requirements of the unit.
Modular HRSGs can be categorized by a number of ways such as direction of exhaust gases flow or number of pressure levels.
The HRSGs systems could be of two type: one, where gas turbine is coupled directly to the steam generator and the major components are disposed in line: superheater, evaporator and economizer (one pressure level); this is the typical application of our burners “DB” type, which are installed inside the duct that connects gas turbine and steam generator. The other type is a classic steam generator: the exhaust gas coming from gas turbine reaches the burners, which are installed on boiler front wall. This is the typical application of our burners “M” or “DM” type, adapted for such application.
In both cases the burner are suitable to work either with hot flue gas stream or fresh air.