What is unfired HRSG?
What is unfired HRSG?
The amount of recoverable steam from gas turbine exhaust in a heat recovery steam generator (HRSG) is a function of the exhaust mass flow, temperature, and boiler effectiveness. The steam profiles indicate what you can reasonably expect without supplementary firing.
How does a HRSG work?
An HRSG is a kind of heat exchanger that recovers heat from the exhaust gases of a gas turbine to an extreme degree. The heat is recovered in the form of steam which is served as the power source of a power-generating steam turbine.
What is supplementary firing?
Supplementary firing is adopted in combined-cycle power plants to reheat low-temperature gas turbine exhaust before entering into the heat recovery steam generator.
What is auxiliary firing?
Auxiliary firing means the combustion of addi- tional fuel downstream of a gas turbine for the purpose of adding thermal energy to the exhaust gases which can be recovered in a waste heat recovery unit.
How the supplementary firing will affect the thermal efficiency?
Studies show that in all operation modes subject to research, using supplementary firing causes an increase in power generation up to 26.3 MW, energy efficiency of steam cycle about 2.43% and decreases the exergy destruction of steam flow control valves.
What does HRSG stand for?
Heat Recovery Steam Generators (HRSG)
What is a duct burner In a 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).
What is a duct burner?
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). Simpler, grid-style systems were later designed to reduce the pressure drop and spread the heat out across the duct.
What does a duct burner do?
Duct burners are capable of firing all fuels suitable for the engine/turbine, as well as many that are not, including heavy oils and waste gases. Supplementary firing is often incorporated into the boiler/heat recovery steam generator (HRSG) design as it allows increased production of steam as demanded by the process.
What are the latest trends in HRSG design?
Recent trends in HRSG design include multiple-pressure units for maximum energy recovery, the use of high-temperature superheaters or reheaters in combined cycle plants and auxiliary firing for efficient steam generation. The first step in designing a HRSG is to calculate the steam generation ability, and gas and steam temperature profiles.
Where does supplemental firing of a HRSG take place?
Supplemental Firing takes place in burners in the gas duct at HRSG inlet. Oil or gas is the supplementary fuel. Since the flue gas at exhaust of a Gas Turbine is high in Oxygen content, additional air is not required for combustion. This eliminates the need of Forced draft or Induced Draft fans.
Why are HRSGs not efficient at high steam pressures?
It may be seen that the exit gas temperature is rather high. With lower pinch and approach points, we could bring it down a little to around 370 F but not to 300 F range. Thus unfired single pressure HRSGs are not very efficient particularly at high steam pressures. The exit gas temperature will be higher at higher steam pressures.
Why does HRSG have a high exit temperature?
The small ratio of steam to gas flow in a HRSG is not adequate to cool the exhaust gases in the economizer, resulting in a high exit gas temperature. Also it can be shown that higher the steam pressure, higher the exit gas temperature and vice versa.
What is unfired HRSG? The amount of recoverable steam from gas turbine exhaust in a heat recovery steam generator (HRSG) is a function of the exhaust mass flow, temperature, and boiler effectiveness. The steam profiles indicate what you can reasonably expect without supplementary firing. How does a HRSG work? An HRSG is a kind of…