Patent ID: 8413445

Claim:
An air fuel assembly for a combustor in a gas turbine, the assembly comprising: a gaseous fuel injection nozzle assembly having a center axis and including a gaseous fuel passage extending along the center axis, and a fuel nozzle at a distal end of the gaseous fuel passage, wherein said gaseous fuel injection nozzle assembly continuously injects gaseous fuel into the gaseous fuel passage; an air tube concentric with the fuel injection nozzle assembly and defining an air passage between the air tube and the fuel injection nozzle assembly, wherein the air tube includes a distal section extending axially beyond the fuel injection nozzle and includes a compressed air inlet adapted to receive compressed air from a compressor in the gas turbine; a first fuel-air mixing zone in the distal section of the air tube and downstream of the fuel injection nozzle, a flame holder comprising a porous structure connected to the distal section of the air tube and defining a downstream end of the first fuel-air mixing zone, wherein, prior to and upstream from combustion, fuel and air from the first fuel-air mixing zone pass through the porous structure of the flame holder and into a combustion zone of the combustor and continuous combustion of the fuel and air first occurs in the combustion zone.