# US 2014/0360200 A1 · Gas turbine power plant with exhaust gas recirculation > Agents: this data is available as JSON from the patentgrep API and MCP server — see https://patentgrep.com/llms.txt - Number: US 2014/0360200 A1 - Document ID: US20140360200A1 - Status: Published application - Kind: A1 - Application number: 14/467,648 - Filed: 2014-08-25 - Published: 2014-12-11 - Earliest claimed: 2012-02-29 - Assignees: Ansaldo Energia Switzerland AG - Applicants: ALSTOM Technology Ltd - Inventors: Eribert BENZ; Jaan Hellat; Hans Wettstein; Robin Payne - Web page: https://patentgrep.com/patent/US20140360200A1 ## CPC - 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 - F01K 13/02: Controlling, e.g. stopping or starting - F01K 23/10: with exhaust fluid of one cycle heating the fluid in another cycle (F01K17/025 takes precedence) - F01K 23/101: {Regulating means specially adapted therefor (F01K23/105, F01K23/108 take precedence)} - F02C 1/005: {being recirculated} - F02C 1/08: Semi-closed cycles - 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 7/042: having variable geometry - F02C 7/057: Control or regulation (conjointly with fuel supply control F02C9/50, with nozzle area control F02K1/16) - F05D 2220/60: making use of surplus or waste energy - F05D 2270/20: to optimize the performance of a machine - 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) - F01K: STEAM ENGINE PLANTS; STEAM ACCUMULATORS; ENGINE PLANTS NOT OTHERWISE PROVIDED FOR; ENGINES USING SPECIAL WORKING FLUIDS OR CYCLES (gas-turbine or jet-propulsion plants F02; nuclear power plants, engine arrangements therein G21D) - F05D: INDEXING SCHEME FOR ASPECTS RELATING TO NON-POSITIVE-DISPLACEMENT MACHINES OR ENGINES, GAS-TURBINES OR JET-PROPULSION PLANTS ## Abstract What is described is a method for operating a gas turbine power plant, in which fresh air is delivered to a compressor inlet and is accelerated in the compressor inlet and a recirculated first exhaust gas substream is delivered into a region of the compressor inlet in which the fresh air is accelerated to an extent such that the difference between total pressure and static pressure in the fresh air is greater than or equal to a pressure difference which is required in order to suck a target mass flow of the recirculated first exhaust gas substream into the compressor inlet. What is described, further, is a gas turbine power plant with a gas turbine, the compressor inlet of which is divided into two sectors which the flow duct of the compressor adjoins, a feeder for fresh air being connected to the first sector and a recirculation line for recirculating the first exhaust gas substream being connected to the second sector, and the second sector reaching so close to the compressor that, when the gas turbine is in operation, the static pressure at the outlet of the second sector is so low that the difference between total pressure and static pressure is greater than or equal to a pressure difference which is required in order to suck a target mass flow of the recirculated first exhaust gas substream into the compressor inlet. ## Claims ### Claim 1 A method for operating a gas turbine power plant with exhaust gas recirculation, which comprises a gas turbine with a compressor inlet, a waste heat recovery steam generator, an exhaust gas divider which divides the exhaust gases into a first exhaust gas substream for recirculation into an intake stream of the gas turbine and into a second exhaust gas substream for discharge into the surroundings, and also a recirculation line and an exhaust gas recooler, said method comprising: fresh air into the compressor inlet and is accelerated in the compressor inlet, delivering recirculated first exhaust gas substream is delivered, separately from the fresh air, into the compressor inlet and coaxially to the fresh air and is conducted, separately from the fresh air, as far as a region of the compressor inlet in which the fresh air is accelerated to an extent such that the difference between total pressure and static pressure in the fresh air is greater than or equal to a pressure difference which is required in order to suck a target mass flow of the recirculated first exhaust gas substream into the compressor inlet. ### Claim 2 (depends on 1) The method as claimed in claim 1, wherein the recirculated first exhaust gas substream and the fresh air are delivered via coaxial annular ducts, the first exhaust gas substream being delivered via a radially inner region of the compressor inlet. ### Claim 3 (depends on 1) The method as claimed in claim 1, wherein the quantity of the recirculated first exhaust gas substream is open loop or close loop controlled by changing the location at which the first exhaust gas substream is delivered to the compressor inlet. ### Claim 4 (depends on 1) The method as claimed in claim 1, wherein the quantity of the recirculated first exhaust gas substream is open loop or close loop controlled by varying the cross-sectional area of an outlet from which the first exhaust gas substream is delivered to the compressor inlet. ### Claim 5 (depends on 1) The method as claimed in claim 1, wherein the quantity of the recirculated first exhaust gas substream is open loop or close loop controlled by adjusting a variable separation element which is arranged in the compressor inlet and which separates the flow duct of the fresh air from the flow duct of the recirculated first exhaust gas substream. ### Claim 6 (depends on 5) The method as claimed in claim 5, wherein the quantity of the recirculated first exhaust gas substream is open loop or close loop controlled by axial displacement of the variable separation element, or in that the quantity of the recirculated first exhaust gas substream is open loop or close loop controlled by radial displacement of the variable separation element. ### Claim 7 (depends on 1) The method as claimed in claim 1, wherein the recirculated first exhaust gas substream is introduced via feeders arranged so as to be distributed in the circumferential direction, upstream of the compressor inlet, on a diameter of the intake duct concentrically to the shaft of the gas turbine, and the quantity of the recirculated first exhaust gas substream is open loop or close loop controlled by changing the axial position of the outlet orifice of the feeders in the compressor inlet. ### Claim 8 (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 conducted into the flow duct of the recirculated first exhaust gas substream via a control or regulating element. ### Claim 9 A gas turbine power plant, comprising a gas turbine, a waste heat recovery steam generator, a compressor inlet and an exhaust gas divider which, during operation, divides the exhaust gases into a first exhaust gas substream for recirculation into an intake stream of the gas turbine and into a second exhaust gas substream for discharge into the surroundings, wherein the compressor inlet is divided into a first sector and a second sector which the flow duct of the compressor adjoins, the first sector and the second sector being arranged coaxially to one another at their outlets, and a feeder for fresh air being connected to the first sector and a recirculation line for recirculating the first exhaust gas substream from the exhaust gas divider being connected to the second sector, and the second sector reaching so close to the compressor that, when the gas turbine is in operation, the static pressure at the outlet of the second sector is so low that the difference between total pressure and static pressure is greater than or equal to a pressure difference which is required in order to suck a target mass flow of the recirculated first exhaust gas substream into the compressor inlet. ### Claim 10 (depends on 9) The gas turbine power plant as claimed in claim 9, wherein the first sector for delivering fresh air and the second sector for delivering recirculated first exhaust gas substream are designed at their outlets as concentric circular rings. ### Claim 11 (depends on 9) The gas turbine power plant as claimed in claim 9, wherein the outlet of the second sector is geometrically variable. ### Claim 12 (depends on 9) The gas turbine power plant as claimed in claim 9, wherein the first sector for delivering fresh air and the second sector for delivering recirculated first exhaust gas substream are separated at their outlet by a variable separation element. ### Claim 13 (depends on 12) The gas turbine power plant as claimed in claim 12, wherein the variable separation element is arranged displaceably in the axial direction, or in that the variable separation element is arranged displaceably in the radial direction. ### Claim 14 (depends on 12) The gas turbine power plant as claimed in claim 12, wherein feeders for introducing the recirculated first exhaust gas substream are arranged so as to be distributed in the circumferential direction in the compressor inlet, upstream of the compressor entry, concentrically to the shaft of the gas turbine, the axial distance from the outlet orifices of the feeders to the compressor entry being adjustable in order to regulate or control the recirculated first exhaust gas sub stream. ### Claim 15 The gas turbine power plant as claimed in 9, wherein the second sector of the compressor entry is connected to a feeder for fresh air via a control or regulating element.