Patent ID: 7584598

Claim:
A method for operating a gas turbine, the method comprising: drawing in and compressing air with the gas turbine; conducting compressed air to a combustor; combusting a syngas that is generated from coal with said compressed air in said combustor to generate hot gases; expanding the hot gases that occur in the course of combustion in a downstream turbine as said hot gases perform work; separating a portion of the compressed air into oxygen and nitrogen; conducting said separated oxygen to and using said separated oxygen in a coal gasifier to produce syngas; conducting a portion of said compressed air to said gas turbine to cool parts of the gas turbine exposed to hot gases; wherein said gas turbine comprises a gas turbine with reheating including two combustors and two turbines, wherein in a first combustor of said two combustors, said syngas is combusted using said compressed air and the resultant hot gases are expanded in a first turbine, and wherein in a second combustor of said two combustors, said syngas is combusted using the gases coming out of the first turbine and the resultant hot gases are expanded in a second turbine; cooling the gas turbine with the nitrogen that occurs in the separation of the air; wherein the gas turbine comprises a first compressor for compressing drawn-in air to an initial pressure stage and a second compressor for compressing the air further from the initial pressure stage to a second, higher pressure stage; cooling said first combustor and said first turbine directly with compressed air from said first compressor; separating a portion of the air coming from the first compressor into oxygen and nitrogen; and using the nitrogen that occurs in the course of said separating to cool the second combustor and second turbine.