Patent ID: 7536863

Claim:
A combined cycle system for generating electric power that is comprised of the following equipment: a gas turbine; a gas turbine compressor; a gas turbine generator; a gas turbine exhaust gas recycle heat recovery unit; an expander; an air compressor; a steam turbine; a steam turbine generator: wherein the combined cycle process comprises the following steps: compressing a gas stream that contains oxygen using the gas turbine compressor; feeding the compressed gas stream into the gas turbine; injecting a stream of fuel gas into the gas turbine and burning the fuel gas in the gas turbine to produce gas turbine shaft power; applying the gas turbine shaft power produced to drive the gas turbine compressor; applying gas turbine shaft power to drive the gas turbine generator to produce electric power; producing a gas turbine exhaust gas stream that is emitted from the gas turbine; dividing the gas turbine exhaust gas stream into two parts—one part to eventually be recycled to the gas turbine and the other part to eventually be expelled from the cycle; conveying the part of the gas turbine exhaust gas stream to be expelled from the cycle to the expander; expanding the gas turbine exhaust gas stream to be expelled in the expander to produce expander shaft power, and an expander turbine exhaust gas stream that is discharged from the expander; applying shaft power produced by the expander to drive the air compressor; using the air compressor to pump a stream of ambient air into the stream of gas turbine exhaust gas stream fraction that is to be recycled to the gas turbine to form the gas stream containing oxygen that is fed into the gas turbine compressor and then pumped into the gas turbine; conveying the part of the gas turbine exhaust gas stream to be recycled to the recycle heat recovery unit; in the heat recovery unit transferring available sensible heat in the gas turbine exhaust gas to a water stream that is fed into the recycle heat recovery unit; converting that water stream to a stream of steam; conveying that steam stream to the steam turbine to drive the steam turbine to produce steam turbine shaft power and an exhaust steam stream; applying steam turbine shaft power to drive the steam turbine electric generator to produce electric power; condensing the exhaust steam produced by the steam turbine to form a stream of water; feeding part of the stream of water to the recycle heat recovery unit as the water stream that is converted to steam.