Air supplying apparatus and method of hybrid power generation equipment

An air supply method for a hybrid power generation facility including a mixing chamber configured to selectively receive combustion gas from a gas turbine that compresses air introduced from an outside, mixes the compressed air with fuel, and burns a mixture of the compressed air and the fuel to produce the combustion gas, an air preheater configured to supply air to the mixing chamber, a burner configured to burn a fluid supplied from the mixing chamber, a first over-firing air supplier configured to receive a fluid from the gas turbine or the air preheater, a first pipeline connecting the gas turbine and the mixing chamber, and a second pipeline connecting the gas turbine and the first over-firing air supplier, the method comprising:

• adjusting a flow rate of the combustion gas flowing through the first pipeline and the second pipeline according to an oxygen concentration in the mixing chamber,
• wherein the hybrid power generation facility further comprises a third pipeline connecting the air preheater and the mixing chamber, a fourth pipeline branched from the third pipeline and connected to the second pipeline to connect the air preheater and the first over-firing air supplier, a second over-firing air supplier configured to selectively receive the combustion gas from the gas turbine, a fifth pipeline branched from the second pipeline and connected to the second over-firing air supplier, and a third damper installed in the fourth pipeline and configured to selectively open and close the fourth pipeline, and
• wherein in a second mode, the combustion gas is supplied to the mixing chamber, the first over-firing air supplier, and the second over-firing air supplier through the first pipeline, the second pipeline, and the fifth pipeline, respectively, the third damper closes the fourth pipeline, and the air preheater supplies air to the mixing chamber through the third pipeline.