Internal manifold air extraction system for IGCC combustor and method

A combustor for a turbine including a combustor liner; a first flow sleeve surrounding the combustor liner with a first flow annulus therebetween, the first flow sleeve having at least one cooling aperture formed about a circumference thereof for directing compressor discharge air as cooling air into the first flow annulus; a casing surrounding first flow sleeve with a second flow annulus therebetween, the first flow sleeve having at least one air extraction opening formed about a circumference thereof for directing compressor discharge air from the first flow annulus as extraction air into the second flow annulus; and an extraction port operatively coupled to the casing for extracting the extraction air from the second flow annulus.