Patent ID: 6598383
Filing Date: 2003-07-29
Classification: F23D,F23R

Abstract:
A method of operating a combustor wherein the combustor has a plurality of outer fuel nozzles in an annular array arranged about a center axis and a center nozzle located on the center axis, and wherein the annular array is selectively supplied with premix fuel, liquid fuel, water and atomizing air, and further wherein the center nozzle is selectively supplied with diffusion fuel and premix fuel, the method comprising the steps of:a) at start-up, supplying the center fuel nozzle with diffusion fuel; b) as the unit load is raised, supplying premix fuel to at least one of the outer nozzles in the annular array; c) at part load, ceasing diffusion fuel flow to the center nozzle and redirecting a corresponding percentage of fuel to at least one of the outer nozzles in the annular array, thereby to maintain fuel flow constant; d) after load is further increased, initiating premix fuel supply to the center nozzle without adding to the supply of premix fuel to the outer fuel nozzles in the annular array; and then e) selectively supplying additional premix fuel to all of the fuel nozzles in the annular array and to the center nozzle as the turbine load increases.