What does a heat recovery steam generator do?
A heat recovery steam generator (HRSG) is one of the major pieces of equipment in a gas turbine combined cycle power plant that boasts a high thermal efficiency and produces minimal CO2 emissions. An HRSG is a kind of heat exchanger that recovers heat from the exhaust gases of a gas turbine to an extreme degree.
Is a boiler the same as a steam generator?
A steam generator is a form of low water-content boiler, similar to a flash steam boiler. The usual construction is as a spiral coil of water-tube, arranged as a single, or monotube, coil. Circulation is once-through and pumped under pressure, as a forced-circulation boiler.
What is the difference between HRSG and boiler?
Most of the HRSG’s are internally insulated so that expansion does not affect the external surfaces and the structures. Conventional boilers on the other hand are top supported and free to expand so the insulation is on the outside.
How can a heat recovery steam generator increase the overall plant efficiency what processes can steam be used for?
HRSGs can be used to generate steam for district heating or factory processes, or to drive a steam turbine to generate more electricity. Used in cogeneration, HRSGs help bring overall plant efficiency to 85%”90%, and the economic and environmental benefits are well recognized.
How many sections does waste heat recovery boiler have in steam generators?
three sections
As such triple pressure HRSGs consist of three sections: an LP (low pressure) section, a reheat/IP (intermediate pressure) section, and an HP (high pressure) section. Each section has a steam drum and an evaporator section where water is converted to steam.
What is once through steam generator?
The OTSG is a vertical shell counterflow straight-tube heat exchanger design which directly generates superheated steam as the feedwater flows through the steam generator in a single pass. BWXT is the exclusive designer and manufacturer of OTSGs for the nuclear industry.
How do steam boilers work?
A steam boiler operates through a combustion reaction between fuel and air, which ignites a flame into tubes that are submerged in water. The heat from this combustion is then transferred from the tube to the water in which the tubes are submerged. The water is then evaporated into steam.
What is the difference between a steam boiler and a steam turbine?
The primary difference between steam and gas turbines is the fact that steam turbines receive power from expanding steam. Fuels such as natural gas can heat condensed water in a boiler, but it’s also possible to utilize renewable thermal energy for this heating.
How efficient is a HRSG?
The HRSG forms a major part of the steam system. In the combined cycle mode, the efficiency of the combined gas turbine-plus-HRSG system can reach 55–60% (lower heating value basis) with modern advanced machines, while in cogeneration mode, the system efficiency can be as high as 75–85%.
What is a duct burner in an HRSG?
Duct burners use supplementary firing to increase the heat energy of a gas turbine’s exhaust, making it possible to increase the output of a downstream heat-recovery steam generator (HRSG). Early systems of the 1960s took a conventional approach to burner design.
What is HRSG efficiency?
Which of the following components of the boiler is used to recover the waste heat of the flue gases for heating feed water?
Recuperators. Recuperators are a form of heat exchanger units that are usually made out of metallic or ceramic materials, depending on their application, and they are used to recover waste exhaust gases at medium to high temperature [32].