Patent ID: 7721552

Claim:
A method of operating a gas turbine power plant wherein the power plant is comprised of: a first gas turbine group, comprised of a first compressor and a first turbine which are connected mechanically with one another, a second gas turbine group comprised of a combustion device, which is placed in a gas flow stream between the first group's first compressor and first turbine, a second compressor, a fuel injection device, a combustion chamber and a second turbine, the second gas turbine group's second compressor and second turbine are mechanically coupled to one another, at least one of the first and second gas turbine groups having a device for extraction of useful work, the method comprising: producing flue gas from the first turbine and heating a first flow of water and/or steam with heat from the flue gas from the first group's turbine, compressing the gas stream from the first turbine in the first compressor, using heat from the compressed gas stream for heating further amounts of water and/or steam with heat from the gas stream that is compressed by the first group's first compressor, injecting the produced water and/or steam into the gas flow stream in such amounts that at least 60% of the oxygen content of the air in the gas flow stream is consumed through combustion in the combustion device, and feeding combustion gas into the second turbine of the second gas turbine group at a pressure in the range 50-300 bar.