Patent ID: 8448445

Claim:
A method for the start-up of a gas turbine of the type having at least one compressor, which compresses the air introduced therein through an inlet duct, at least one combustor, in which said compressed air is mixed and combusted with a gaseous fuel, coming from a feeding duct, and at least one turbine, which transforms the energy of the combusted gas coming from said combustor into work energy, the method comprising the following phases: a) establishing a predetermined minimum value (FSR 1 ) of the fuel flow entering said combustor and effecting a first attempt at ignition, wherein the predetermined minimum value is established by being set at a value that is sufficient to ignite a richest fuel/air mixture among a predetermined group of gaseous fuels; and b) progressively increasing the value (FSR n ) of the fuel flow entering said combustor and effecting further attempts at ignition until the complete ignition of the air/fuel mixture and consequent start-up of said turbine, or until a predetermined maximum value (FSR max ) of said fuel flow is reached, wherein in said phase b) an intermediate purging cycle of said discharge duct is effected, interrupting the flow of gaseous fuel to said combustor before the increase in said value (FSR n ) of the fuel flow.