# US 9,752,502 B2 · Power generation system exhaust cooling > Agents: this data is available as JSON from the patentgrep API and MCP server — see https://patentgrep.com/llms.txt - Number: US 9,752,502 B2 - Document ID: US9752502B2 - Status: Granted - Kind: B2 - Application number: 14/753,066 - Filed: 2015-06-29 - Published: 2016-12-29 - Granted: 2017-09-05 - Earliest claimed: 2015-06-29 - Assignees: General Electric Company - Applicants: General Electric Company - Inventors: Lewis Berkley Davis, Jr.; Parag Prakash Kulkarni; Robert Joseph Reed - Web page: https://patentgrep.com/patent/US9752502B2 ## CPC - F02C 7/141: of working fluid - F01D 25/305: {with fluid, e.g. liquid injection} - F02C 6/08: the gas being bled from the gas-turbine compressor - F02C 7/18: the medium being gaseous, e.g. air {(F02C7/125 takes precedence)} - F02C 9/18: by bleeding, bypassing or acting on variable working fluid interconnections between turbines or compressors or their stages {(F02C3/113 takes precedence)} - F01N 3/2066: {Selective catalytic reduction [SCR]} - F02K 3/00: Plants including a gas turbine driving a compressor or a ducted fan - F05D 2270/082: with as little NOx as possible - 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) - F01N: GAS-FLOW SILENCERS OR EXHAUST APPARATUS FOR MACHINES OR ENGINES IN GENERAL; GAS-FLOW SILENCERS OR EXHAUST APPARATUS FOR INTERNAL-COMBUSTION ENGINES (arrangements in connection with gas exhaust of propulsion units in vehicles B60K13/00; combustion-air intake silencers specially adapted for, or arranged on, internal-combustion engines F02M35/00; protecting against, or damping, noise in general G10K11/16) - F02K: JET-PROPULSION PLANTS (features of jet-propulsion plants common to gas-turbine plants, air intakes or fuel supply control of air-breathing jet-propulsion plants F02C7/00, F02C9/00) - F05D: INDEXING SCHEME FOR ASPECTS RELATING TO NON-POSITIVE-DISPLACEMENT MACHINES OR ENGINES, GAS-TURBINES OR JET-PROPULSION PLANTS ## Abstract An airflow control system for a gas turbine according to an embodiment includes: an airflow generation system for attachment to a rotatable shaft of a gas turbine system, the airflow generation system drawing in an excess flow of air through an air intake section; a mixing area for receiving an exhaust gas stream of the gas turbine system; an air extraction system for: extracting at least a portion of the excess flow of air generated by the airflow generation system to provide bypass air; and diverting the bypass air into the mixing area to reduce a temperature of the exhaust gas stream; and an exhaust processing system for processing the reduced temperature exhaust gas stream. ## Claims ### Claim 1 An airflow control system for a gas turbine system, comprising: an airflow generation system for attachment to a rotatable shaft of a gas turbine system, the airflow generation system drawing in an excess flow of air through an air intake section, the airflow generation system including a fan and a plurality of inlet guide vanes in the air intake section upstream from the fan, the excess flow of air passing through the inlet guide vanes, the inlet guide vanes controlling the excess flow of air passing through the air intake section toward and through the fan; a mixing area for receiving an exhaust gas stream of the gas turbine system; an air extraction system for extracting at least a portion of the excess flow of air generated by the airflow generation system to provide bypass air, and for diverting the bypass air into the mixing area to reduce a temperature of the exhaust gas stream, the air extraction system including an air splitting system comprising: an outer bypass duct for diverting the bypass air around the gas turbine system into the mixing area to reduce the temperature of the exhaust gas stream in the mixing area, wherein the outer bypass duct comprises an arrangement of axially extending ducts, the axially extending ducts arrayed circumferentially around the gas turbine system to surround the gas turbine system; and an inner passage for directing any non-extracted portion of the excess flow of air into a compressor component of the gas turbine system to supercharge the gas turbine system; and a selective catalytic reduction (SCR) system for processing the reduced temperature exhaust gas stream from the mixing area. ### Claim 2 (depends on 1) The airflow control system of claim 1, wherein the fan is fixedly coupled to the shaft or releasably coupled to the shaft using a clutch mechanism. ### Claim 3 (depends on 1) The airflow control system of claim 1, further comprising a mixing system for mixing the bypass air with the exhaust gas stream in the mixing area. ### Claim 4 (depends on 1) The airflow control system of claim 1, further comprising a flow restriction system coupled to the bypass duct for selectively restricting the amount of bypass air flowing into the bypass duct. ### Claim 5 (depends on 1) The airflow control system of claim 1, wherein the compressor component draws in a flow of air, and wherein the excess flow of air drawn in by the airflow generation system comprises about 10 percent to about 40 percent of the flow of air drawn in by the compressor component of the gas turbine system. ### Claim 6 (depends on 1) The airflow control system of claim 1, further comprising an airflow controller for controlling the air extraction system to maintain the reduced temperature exhaust gas stream at a temperature of less than about 900° F. ### Claim 7 A turbomachine system, comprising: a gas turbine system including a compressor component, a combustor component, and a turbine component; a shaft driven by the turbine component; a fan coupled to the shaft upstream of the gas turbine system for drawing in an excess flow of air through an air intake section; a mixing area for receiving an exhaust gas stream produced by the gas turbine system; an air extraction system for: extracting at least a portion of the excess flow of air generated by the fan to provide bypass air; and diverting the bypass air into the mixing area to reduce a temperature of the exhaust gas stream; the air extraction system including an air splitting system comprising: an outer bypass duct for diverting the bypass air around the gas turbine system into the mixing area to reduce the temperature of the exhaust gas stream in the mixing area, wherein the outer bypass duct comprises an arrangement of axially extending ducts, the axially extending ducts arrayed circumferentially around the gas turbine system to surround the gas turbine system; and an inner passage for directing any non-extracted portion of the excess flow of air into the compressor component of the gas turbine system to supercharge the gas turbine system; an airflow controller for controlling the air extraction system to maintain the reduced temperature exhaust gas stream at a temperature of less than about 900° F.; and a selective catalytic reduction (SCR) system for processing the reduced temperature exhaust gas stream from the mixing area. ### Claim 8 (depends on 7) The turbomachine system of claim 7, further comprising at least one inlet guide vane for controlling a flow of air through the fan, each inlet guide vane coupled to an actuator configured to rotate the inlet guide vane. ### Claim 9 (depends on 7) The turbomachine system of claim 7, wherein the fan is either fixedly coupled to the shaft or releasably coupled to the shaft using a clutch mechanism. ### Claim 10 (depends on 7) The turbomachine system of claim 7, further comprising a mixing system for mixing the bypass air with the exhaust gas stream in the mixing area. ### Claim 11 (depends on 7) The turbomachine system of claim 7, further comprising a flow restriction system coupled to the bypass duct for selectively restricting the amount of bypass air flowing into the bypass duct. ### Claim 12 (depends on 7) The turbomachine system of claim 7, wherein the excess flow of air drawn in by the airflow generation system comprises about 10 percent to about 40 percent of a flow of air drawn in by the compressor component. ### Claim 13 A power generation system, comprising: a gas turbine system including a compressor component, a combustor component, and a turbine component; a shaft driven by the turbine component; an electrical generator coupled to the shaft for generating electricity; a fan coupled to the shaft upstream of the gas turbine system for drawing in an excess flow of air through an air intake section; a mixing area for receiving an exhaust gas stream produced by the gas turbine system; an air extraction system for: extracting at least a portion of the excess flow of air generated by the can to provide bypass air; and diverting the bypass air into the mixing area to reduce a temperature of the exhaust gas stream; the air extraction system including an air splitting system comprising: an outer bypass duct for diverting the bypass air around the gas turbine system into the mixing area to reduce the temperature of the exhaust gas stream in the mixing area, wherein the outer bypass duct comprises an arrangement of axially extending ducts, the axially extending ducts arrayed circumferentially around the gas turbine system to surround the gas turbine system; and an inner passage for directing any non-extracted portion of the excess flow of air into the compressor component of the gas turbine system to supercharge the gas turbine system; an airflow controller for controlling the air extraction system to maintain the reduced temperature exhaust gas stream at a temperature of less than about 900° F.; and a selective catalytic reduction (SCR) system for processing the reduced temperature exhaust gas stream.