Patent ID: 7181916
Filing Date: 2007-02-27
Classification: F23D,F23R,Y02E

Abstract:
1. A method for combustion in a combustor in a gas turbine, wherein said combustor comprises an annular array of outer fuel nozzles arranged about a center axis and a small center fuel nozzle aligned with the center axis, and a bluff body associated with the center fuel nozzle, said method comprising: a. fueling the center fuel nozzle with a fuel-rich mixture of gaseous fuel and air and fueling the outer fuel nozzles with a fuel-lean mixture of fuel and air; b. igniting the fuel-rich mixture injected by the center fuel nozzle while the fuel-lean mixture injected by the outer fuel nozzles is insufficient to sustain ignition; c. stabilizing a flame on the center fuel nozzle using the bluff body and while the outer fuel nozzles inject the fuel-lean mixture; d. staging fuel to the outer nozzles by increasing a fuel ratio of the fuel-lean mixture, and e. after the outer nozzles sustain ignition, reducing the fuel applied to the center nozzle.