OPERATION METHOD OF GAS TURBINE COMBUSTOR

PURPOSE:To improve combustion efficiency and ensure pilot combustion with the reduced production amount of NOx by previously setting an air-fuel ratio of a pilot burner and a mixing ratio of pilot combustion gas and premixing air within proper ranges respectively. CONSTITUTION:When an air mass flow rate of a first premixing burner 9 is assumed to be A1 and air mass of a second premixing burner 12 to be A2, a combustor 2 is constructed such that A2=0.39 to 0.8XAl holds. When a fuel mass flow rate of a diffusion burner 8 is assumed to be Fp, t:and a fuel mass flow rate of the first premixing burner 9 to be F1, the diffusion burner 8 and the first premixing burner 9 are operated until (Fp+F1)/(A1+A2)>0.020 holds. Thereafter, a fuel flow rate of a second premixing burner fuel system 202 is thrown in for the operation. Then, premixed air is mixed with a strong shearing layer formed with oppositely rotating spiral motions, and gets high temperature. Accordingly, combustion efficiency of the pilot burner is improved and combustion with the reduced production amount of NOx is ensured.