# US 9,429,075 B2 · Method of operating a fuel heating system > Agents: this data is available as JSON from the patentgrep API and MCP server — see https://patentgrep.com/llms.txt - Number: US 9,429,075 B2 - Document ID: US9429075B2 - Status: Granted - Kind: B2 - Application number: 13/755,434 - Filed: 2013-01-31 - Published: 2014-07-31 - Granted: 2016-08-30 - Earliest claimed: 2013-01-31 - Assignees: General Electric Company - Applicants: General Electric Company - Inventors: Rushi Mahesh Amin; Douglas Scott Byrd; Dean Matthew Erickson; Michael John Mariani; Christina Renee Pompey; Korey Frederic Rendo; Bryan Edward Sweet - Web page: https://patentgrep.com/patent/US9429075B2 ## CPC - F02C 7/224: Heating fuel before feeding to the burner - F02C 7/232: Fuel valves {(control of fuel supply by means of fuel metering valves F02C9/263)}; Draining valves or systems (valves in general F16K) - F02C 7/26: Starting; Ignition - F02C 9/26: Control of fuel supply (F02C9/48 takes precedence; fuel valves F02C7/232) - F05D 2230/31: Layer deposition - F05D 2230/312: by plasma spraying - F05D 2260/80: Diagnostics - F05D 2270/08: to produce clean exhaust gases - 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) - F05D: INDEXING SCHEME FOR ASPECTS RELATING TO NON-POSITIVE-DISPLACEMENT MACHINES OR ENGINES, GAS-TURBINES OR JET-PROPULSION PLANTS ## Abstract A method of operating a fuel heating system is provided. The method includes performing pre-ignition diagnostic checks on a plurality of components of the fuel heating system, wherein at least one inlet damper and at least one outlet damper of an exhaust flow circuit are each in a closed position. The method also includes purging the fuel heating system of unburned hydrocarbons. The method further includes operating the fuel heating system in a normal operating condition. The method yet further includes operating the fuel heating system in a cool down condition, wherein the at least one inlet damper is in the closed position. ## Claims ### Claim 1 A method of operating a fuel heating system, the fuel heating system including an exhaust flow circuit configured to heat a fuel flow circuit having at least one inlet damper, at least one outlet damper, and at least one recirculation damper, the method comprising: performing pre-ignition diagnostic checks on a plurality of components of the fuel heating system, wherein, during the performing of the pre-ignition diagnostic checks, the at least one inlet damper and the at least one outlet damper are each in a closed position; purging the fuel heating system of an accumulation of unburned hydrocarbons; operating the fuel heating system in a normal operating condition; and operating the fuel heating system in a cool down condition, wherein, during the operating of the fuel heating system in the cool down condition, the at least one inlet damper is in the closed position, wherein the at least one inlet damper controls an amount of exhaust air that enters the exhaust flow circuit via a supply path, the at least one outlet damper controls an amount of exhaust air that exits the exhaust flow circuit via an outlet path, and the at least one recirculation damper controls an amount of exhaust air that is recirculated in the exhaust flow circuit from the outlet path to the supply path via a recirculation path. ### Claim 2 (depends on 1) The method of claim 1, wherein the performing of the pre-ignition diagnostic checks further comprises diagnostically checking a plurality of valves and a plurality of dampers prior to starting a gas turbine engine in communication with the fuel heating system. ### Claim 3 (depends on 1) The method of claim 1, further comprising performing a fuel leak check of a fuel heater with at least one methane detection device. ### Claim 4 (depends on 3) The method of claim 3, further comprising opening the at least one recirculation damper to the open position during the performing of the fuel leak check, wherein the performing of the fuel leak check is conducted subsequent to starting a gas turbine engine in communication with the fuel heating system. ### Claim 5 (depends on 3) The method of claim 3, further comprising opening an isolation valve for allowing a flow of a fuel from a fuel supply arrangement to the fuel heater, for pressurization of the fuel heater. ### Claim 6 (depends on 1) The method of claim 1, further comprising opening the at least one inlet damper to the open position and opening both of the at least one outlet damper and the at least one recirculation damper to a partially open position during purging of the fuel heating system. ### Claim 7 (depends on 6) The method of claim 6, further comprising extracting an exhaust air as an incoming exhaust airflow of a gas turbine engine for flowing of the exhaust air over a fuel heater of the fuel heating system, wherein a fluid circulation device at least partially facilitates flowing of the exhaust air throughout the exhaust flow circuit. ### Claim 8 (depends on 1) The method of claim 1, wherein the operating the fuel heating system in the normal operating condition is conducted subsequent to ignition of a gas turbine engine in communication with the fuel heating system. ### Claim 9 (depends on 8) The method of claim 8, wherein the operating the fuel heating system in the normal operating condition comprises: extracting an exhaust air as an incoming exhaust airflow from an exhaust stack by opening the at least one inlet damper; recirculating the exhaust air for mixing with additional incoming exhaust airflow by opening the at least one recirculation damper; and expelling the exhaust air to the exhaust stack by opening the at least one outlet damper, wherein the at least one recirculation damper and the at least one outlet damper regulate an inlet temperature of the exhaust air proximate the at least one inlet damper. ### Claim 10 (depends on 1) The method of claim 1, wherein a fluid circulation device at least partially facilitates flowing of an exhaust air throughout the exhaust flow circuit. ### Claim 11 (depends on 1) The method of claim 1, wherein operating the fuel heating system in the normal operating condition further comprises flowing a fuel from a fuel supply disposed proximate a fuel flow circuit inlet through a fuel heater to a fuel flow circuit outlet for delivery of heated fuel to a gas turbine engine. ### Claim 12 (depends on 11) The method of claim 11, further comprising controlling a fuel mixing valve for selectively routing a portion of unheated fuel from the fuel supply to the fuel flow circuit outlet for mixing of unheated fuel with heated fuel. ### Claim 13 (depends on 1) The method of claim 1, wherein operating the fuel heating system in the cool down condition further comprises routing an exhaust air through the exhaust flow circuit, wherein the exhaust air is routed through the recirculation path controlled by the at least one recirculation damper and the outlet path controlled by the at least one outlet damper. ### Claim 14 (depends on 13) The method of claim 13, further comprising opening the at least one recirculation damper a greater extent than the at least one outlet damper for routing a majority of the exhaust air through the recirculation path. ### Claim 15 (depends on 13) The method of claim 13, further comprising closing a fuel mixing valve configured to selectively route a portion of unheated fuel from a fuel supply from proximate a fuel flow circuit inlet to a fuel flow circuit outlet. ### Claim 16 (depends on 1) The method of claim 1, further comprising operating the fuel heating system in a shutdown condition, wherein the at least one inlet damper is in the closed position and the at least one outlet damper and the at least one recirculation damper are each in a partially open position. ### Claim 17 A method of operating a fuel heating system, the fuel heating system including an exhaust flow circuit configured to heat a fuel flow circuit having at least one inlet damper, at least one outlet damper, and at least one recirculation damper, the method comprising: performing pre-ignition diagnostic checks on a plurality of components of the fuel heating system; purging the fuel heating system of an accumulation of unburned hydrocarbons; operating the fuel heating system in a normal operating condition; operating the fuel heating system in a cool down condition; operating the fuel heating system in a shutdown condition, wherein, during the shutdown condition, the at least one outlet damper and the at least one recirculation damper are each opened to a position that allows an equal amount of the exhaust air to flow through the at least one outlet damper and at least one recirculation damper; and monitoring the fuel heating system, wherein the fuel heating system initiates at least one protective mode upon detection of an abnormal operating characteristic, wherein the at least one inlet damper controls an amount of exhaust air that enters the exhaust flow circuit via a supply path, the at least one outlet damper controls an amount of exhaust air that exits the exhaust flow circuit via an outlet path, and the at least one recirculation damper controls an amount of exhaust air that is recirculated in the exhaust flow circuit from the outlet path to the supply path via a recirculation path. ### Claim 18 (depends on 17) The method of claim 17, wherein the at least one protective mode comprises isolating the exhaust flow circuit from a heat source for cooling down a fuel heater, wherein isolating the exhaust flow circuit comprises: closing one of: the at least one inlet damper or the at least one outlet damper; and closing a fuel mixing valve configured to selectively route a portion of unheated fuel from a fuel supply from proximate a fuel flow circuit inlet to a fuel flow circuit outlet. ### Claim 19 (depends on 18) The method of claim 18, wherein the at least one protective mode further comprises isolating the fuel heater from the fuel flow circuit, wherein isolating the fuel heater from the fuel flow circuit comprises: closing at least one fuel isolation valve configured to control fuel flow from the fuel supply to the fuel heater; and opening the fuel mixing valve. ### Claim 20 (depends on 19) The method of claim 19, further comprising opening a heater vent valve for venting fuel from the fuel heater.