# US 2014/0360199 A1 · Method of operating a gas turbine power plant with exhaust gas recirculation and corresponding gas turbine power plant > Agents: this data is available as JSON from the patentgrep API and MCP server — see https://patentgrep.com/llms.txt - Number: US 2014/0360199 A1 - Document ID: US20140360199A1 - Status: Published application - Kind: A1 - Application number: 14/467,500 - Filed: 2014-08-25 - Published: 2014-12-11 - Earliest claimed: 2012-02-29 - Assignees: Ansaldo Energia Switzerland AG - Applicants: ALSTOM Technology Ltd - Inventors: Jaan HELLAT; Eribert Benz; Frank Graf; Torsten Wind; Felix Guethe; Klaus Doebbeling - Web page: https://patentgrep.com/patent/US20140360199A1 ## CPC - F02C 3/30: Adding water, steam or other fluids {for influencing combustion, e.g. to obtain cleaner exhaust gases (F02C7/141, F02C7/30, F01D21/00, F01K21/04, F23D11/10 take precedence)} - F01D 5/141: {Shape, i.e. outer, aerodynamic form (F01D5/148 - F01D5/20 take precedence; blade construction F01D5/147)} - F02C 3/06: the compressor comprising only axial stages (F02C3/10 takes precedence) - F02C 3/34: with recycling of part of the working fluid, i.e. semi-closed cycles with combustion products in the closed part of the cycle - F02C 6/003: {Gas-turbine plants with heaters between turbine stages} - F02C 6/08: the gas being bled from the gas-turbine compressor - F02C 6/18: using the waste heat of gas-turbine plants outside the plants themselves, e.g. gas-turbine power heat plants (using waste heat as source of energy for refrigeration plants F25B27/02; using the waste heat of a gasturbine for steam generation or in a steam cycle see F01K23/10) - F02C 7/04: Air intakes for gas-turbine plants or jet-propulsion plants - F02C: GAS-TURBINE PLANTS; AIR INTAKES FOR JET-PROPULSION PLANTS; CONTROLLING FUEL SUPPLY IN AIR-BREATHING JET-PROPULSION PLANTS (construction of turbines F01D; jet-propulsion plants F02K; construction of compressors or fans F04; generating combustion products of high pressure or high velocity F23R; using gas turbines in compression refrigeration plants F25B11/00) - F01D: NON-POSITIVE DISPLACEMENT MACHINES OR ENGINES, e.g. STEAM TURBINES (machines or engines for liquids F03; non-positive displacement pumps F04D) ## Abstract The invention relates to a method for operating a gas turbine, in which an oxygen-reduced gas and fresh air are delivered to a compressor of the gas turbine in a radially staged manner, the fresh air being delivered via an outer sector of the inlet cross section in relation to the axis of rotation of the compressor, and the oxygen-reduced gas being delivered via an inner sector of the inlet cross section in relation to the axis of rotation of the compressor. The invention relates, further, to a gas turbine power plant with a gas turbine having a compressor inlet which is followed by the flow duct of the compressor and which is divided into an inner sector and an outer sector, a feed for an oxygen-reduced gas being connected to the inner sector of the compressor inlet, and a fresh air feed being connected to the outer sector of the compressor inlet. ## Claims ### Claim 1 A method for operating a gas turbine, having a compressor with an inlet cross section, a combustion chamber and a turbine, said method comprising: delivering an oxygen-reduced gas, which has an oxygen concentration which is lower than the average oxygen concentration of the compressor intake flow, and fresh air to the compressor in a radially staged manner, wherein the fresh air being delivered via an outer sector of the inlet cross section in relation to an axis of rotation of the compressor, and the oxygen-reduced gas being delivered via an inner sector of the inlet cross section in relation to the axis of rotation of the compressor. ### Claim 2 (depends on 1) The method as claimed in claim 1, wherein the exhaust gases of the gas turbine are divided into a first exhaust gas flow for recirculation into the intake flow of the gas turbine and into a second exhaust gas flow for discharge into the surroundings, and the first exhaust gas flow is delivered as oxygen-reduced gas to the compressor via the inner sector of the inlet cross section. ### Claim 3 (depends on 1) The method as claimed in claim 1, wherein at least 95% of the oxygen-reduced gas is guided into the combustion chamber of the gas turbine. ### Claim 4 (depends on 1) The method as claimed in claim 1, wherein the fresh air is introduced into the compressor inlet without being intermixed with the oxygen-reduced gas, and at least part of the fresh air compressed in the compressor is branched off as cooling gas for the cooling of hot gas parts. ### Claim 5 (depends on 1) The method as claimed in claim 1, wherein the oxygen-reduced gas is introduced via feeds arranged, upstream of the compressor inlet, so as to be distributed in the circumferential direction on a diameter of the intake duct concentrically with respect to the axis of rotation of the compressor. ### Claim 6 (depends on 1) The method as claimed in claim 1, wherein the oxygen content of the gases compressed by the compressor and introduced into the combustion chamber is at least 3% below the average oxygen content of the cooling gases branched off from the compressor. ### Claim 7 (depends on 1) The method as claimed in claim 1, wherein a lean gas is delivered via the inner sector of the intake cross section of the compressor. ### Claim 8 (depends on 2) The method as claimed in claim 2, wherein the first exhaust gas flow and the lean gas are delivered via the inner sector. ### Claim 9 (depends on 1) The method as claimed in claim 1, wherein, when the gas turbine is under part load and/or is being started, fresh air is guided into the inner sector of the compressor inlet via a regulating element. ### Claim 10 A gas turbine power plant, comprising a gas turbine with a compressor inlet, with a compressor, with a combustion chamber following the compressor, and with a turbine following the combustion chamber, wherein the compressor inlet, which the flow duct of the compressor follows, is divided into an inner sector in relation to the axis of rotation of the compressor and an outer sector in relation to the axis of rotation of the compressor, a feed for an oxygen-reduced gas, which has an oxygen concentration which is lower than the average oxygen concentration of the compressor intake flow during the operation of the gas turbine, being connected to the inner sector of the compressor inlet, and a fresh air feed being connected to the outer sector of the compressor inlet. ### Claim 11 (depends on 10) The gas turbine power plant as claimed in claim 10, wherein the gas turbine power plant comprises an exhaust gas divider which is connected by means of a recirculation line to the inner sector for the recirculation of a first exhaust gas flow as oxygen-reduced gas and which is connected to an exhaust gas line for the discharge of a second exhaust gas flow into the surroundings. ### Claim 12 (depends on 10) The gas turbine power plant as claimed in claim 10, wherein the inner sector and the outer sector are separated by an inlet guide plate, and in that the inner sector and the outer sector of the compressor inlet are designed as concentric circular rings at the connection to the flow duct of the compressor. ### Claim 13 (depends on 10) The gas turbine power plant as claimed in claim 10, wherein the area ratio of the area of connection of the outer sector to the flow duct of the compressor to the area of connection of the inner sector to the flow duct of the compressor is selected so as to be equal to the ratio of the volume flows of the delivered fresh air to the first exhaust gas flow under the design conditions of the gas turbine. ### Claim 14 (depends on 10) The gas turbine power plant as claimed in claim 10, wherein it comprises a regulating element, by means of which the area ratio of the area of connection of the outer sector to the flow duct of the compressor to the area of connection of the inner sector to the flow duct of the compressor can be varied, in order to match the area ratio to changes in the ratio between the delivered fresh air and the recirculated first exhaust gas flow. ### Claim 15 (depends on 10) The gas turbine power plant as claimed in claim 10, wherein a multiplicity of feed ducts for introducing the oxygen-reduced gas into the inner sector of the compressor inlet are arranged in the compressor inlet so as to be distributed in a circumferential direction on a circle concentrically with respect to the axis of the gas turbine.