A gas turbine is conventionally comprised of a compressor, a combustor, and a turbine. The turbine is coupled to the compressor in order to drive the compressor. The combustion chamber receives fuels such as a combustion gas, and a certain amount of nitrogen, to lower the flame temperature in the combustion chamber of the combustor, which makes it possible to minimize the discharge of nitrogen oxides to atmosphere. The combustion gas may be obtained by gasification, that is, oxidation of carbon products such as coal. This partial oxidation is carried in an independent unit referred to as a gasifier. Conventionally, the gas turbine is combined with an air separation unit. The air separation unit enables at least one gas stream, mostly consisting of one of the gases of air, especially oxygen or nitrogen, to be supplied from input air. To combine the air separation unit with the gas turbine, the oxygen and nitrogen produced in the air separation unit are admitted respectively into the gasifier and the combustion chamber of the combustor.