# US 9,435,227 B2 · Gas-to-liquid heat exchange system with multiple liquid flow patterns > Agents: this data is available as JSON from the patentgrep API and MCP server — see https://patentgrep.com/llms.txt - Number: US 9,435,227 B2 - Document ID: US9435227B2 - Status: Granted - Kind: B2 - Application number: 13/798,462 - Filed: 2013-03-13 - Published: 2014-09-18 - Granted: 2016-09-06 - Earliest claimed: 2013-03-13 - Assignees: Nooter/Eriksen, Inc. - Applicants: Nooter/Eriksen, Inc. - Inventors: Yuri Rechtman - Web page: https://patentgrep.com/patent/US9435227B2 ## CPC - F01K 23/10: with exhaust fluid of one cycle heating the fluid in another cycle (F01K17/025 takes precedence) - F22B 1/1815: {using the exhaust gases of gas-turbines} - F22B 35/007: {Control systems for waste heat boilers} - F22B 37/025: {Devices and methods for diminishing corrosion, e.g. by preventing cooling beneath the dew point} - F22D 1/003: {Feed-water heater systems (F22D1/325, F22D1/36 and F22D1/40 take precedence)} - F22D 5/34: Applications of valves - Y02E 20/16: Combined cycle power plant [CCPP], or combined cycle gas turbine [CCGT] - 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) - F22B: METHODS OF STEAM GENERATION; STEAM BOILERS - F22D: PREHEATING, OR ACCUMULATING PREHEATED, FEED-WATER FOR STEAM GENERATION; FEED-WATER SUPPLY FOR STEAM GENERATION; CONTROLLING WATER LEVEL FOR STEAM GENERATION; AUXILIARY DEVICES FOR PROMOTING WATER CIRCULATION WITHIN STEAM BOILERS - Y02E: REDUCTION OF GREENHOUSE GAS [GHG] EMISSIONS, RELATED TO ENERGY GENERATION, TRANSMISSION OR DISTRIBUTION ## Abstract Systems and methods for the design of a heat recovery steam generator (HRSG) or similar system that is designed to extract heat from hot gases flowing through a duct which utilizes an external liquid-to-liquid heat exchanger for preheating feedwater. The systems and methods allow for multiple water flow patterns to adjust the temperature of the feedwater into the gas duct. ## Claims ### Claim 1 A piping system for transferring heat from an exhaust gas flow to a feedwater comprising: an economizer including: a first section; a second section; a third section; and a fourth section; wherein said first section, said second section, said third section, and said fourth section are within said gas flow; a heat exchanger which is not within said exhaust gas flow and having a cold input and hot input; and a plurality of valves comprising; a first three-way valve positioned between an upstream face of said first section of said economizer, an upstream face of said third section of said economizer, and said hot input of said heat exchanger; a second three-way valve positioned between an upstream face of said first section of said economizer, an upstream face of said second section of said economizer, and a downstream face of said third section of said economizer; and a first two-way valve positioned between an upstream face of said third section of said economizer and an upstream face of said fourth section of said economizer; wherein said valves in said plurality of valves can be arranged in a first configuration so a feedwater passes through the system in the following order: a) said cold input of said heat exchanger; b) said first section of said economizer; c) said hot input of said heat exchanger; d) said second section of said economizer; and e) at least one of said third and said fourth section of said economizer in-any order; and wherein said valves in said plurality of valves can be arranged in a second configuration so a feedwater passes through the system in the following order: a) said cold input of said heat exchanger; b) said first section of said economizer; c) said third section of said economizer; d) said hot input of said heat exchanger; e) said second section of said economizer; and f) said fourth section of said economizer. ### Claim 2 (depends on 1) The system of claim 1, wherein said exhaust gas flow is selected from the group consisting of: exhaust gas from the combustion of natural gas and exhaust gas from the combustion of #2 fuel oil. ### Claim 3 (depends on 2) The system of claim 2, wherein said valves in said plurality of valves are arranged in said first configuration when said exhaust gas is from the combustion of natural gas and in said second configuration when said exhaust gas is from the combustion of #2 fuel oil. ### Claim 4 (depends on 1) The system of claim 1, wherein said first section of said economizer and said second section of said economizer are arranged in parallel relative to said exhaust gas flow. ### Claim 5 (depends on 1) The system of claim 1, wherein said first section of said economizer and said second section of said economizer are arranged in series relative to said exhaust gas flow. ### Claim 6 (depends on 1) The system of claim 1, wherein said third section of said economizer and said fourth section of said economizer are arranged in parallel relative to said exhaust gas flow. ### Claim 7 (depends on 1) The system of claim 1, wherein said third section of said economizer and said fourth section of said economizer are arranged in series relative to said exhaust gas flow. ### Claim 8 (depends on 1) The system of claim 1, wherein said plurality of valves further includes a bypass valve which allows for said feedwater to either: enter the cold input of said heat exchanger; or bypass said economizer. ### Claim 9 (depends on 1) The system of claim 1, wherein said feedwater entering said cold input is between about 90° F. and about 100° F. ### Claim 10 (depends on 9) The system of claim 9, wherein, when said valves are in said first configuration, said feedwater entering said first section of said economizer is above 140° F. ### Claim 11 (depends on 1) The system of claim 1, wherein said system is part of a heat recovery steam generator (HRSG). ### Claim 12 (depends on 1) The system of claim 1, wherein after said feedwater has passed through either said first configuration or said second configuration, said feedwater is passed to a low pressure evaporator. ### Claim 13 A method for controlling the flow of a liquid through a device for exchanging heat between a gas and a liquid, the method comprising: providing a device for exchanging heat between a gas and a liquid, the device including: an economizer including: a first section; a second section; a third section; and a fourth section; wherein said first section, said second section, said third section, and said fourth section are within said gas flow; a heat exchanger which is not within said exhaust gas flow and having a cold input and hot input; using said device in a first configuration wherein liquid passes through the components of the device in the following order: a) said cold input of said heat exchanger; b) said first section of said economizer; c) said hot input of said heat exchanger; d) said second section of said economizer; and e) at least one of said third and said fourth section of said economizer; when a first exhaust gas forms said exhaust gas flow; and using said device in a second configuration wherein liquid passes through the components of the device in the following order: a) said cold input of said heat exchanger; b) said first section of said economizer; c) said third section of said economizer; d) said hot input of said heat exchanger; e) said second section of said economizer; and f) said fourth section of said economizer; when a second exhaust gas, different from said first exhaust gas, forms said exhaust gas flow. ### Claim 14 (depends on 13) The method of claim 13, wherein said first exhaust gas is exhaust gas from the combustion of natural gas and said second exhaust gas is exhaust gas from the combustion of #2 fuel oil. ### Claim 15 (depends on 13) The method of claim 13, wherein said first exhaust gas has a lower sulfur content than said second exhaust gas. ### Claim 16 (depends on 13) The method of claim 13, wherein said first section of said economizer and said second section of said economizer are arranged in parallel relative to said exhaust gas flow. ### Claim 17 (depends on 13) The method of claim 13, wherein said first section of said economizer and said second section of said economizer are arranged in series relative to said exhaust gas flow. ### Claim 18 (depends on 13) The method of claim 13, wherein said third section of said economizer and said fourth section of said economizer are arranged in parallel relative to said exhaust gas flow. ### Claim 19 (depends on 13) The method of claim 13, wherein said third section of said economizer and said fourth section of said economizer are arranged in series relative to said exhaust gas flow. ### Claim 20 (depends on 13) The method of claim 13, wherein said liquid entering said cold input is between about 90° F. and about 100° F. ### Claim 21 (depends on 13) The method of claim 13, wherein, in said first configuration, said liquid entering said first section of said economizer is above 140° F. ### Claim 22 (depends on 13) The method of claim 13, wherein, in said second configuration, said liquid entering said first section of said economizer is above 230° F. ### Claim 23 (depends on 13) The method of claim 13, wherein said method is performed in a heat recovery steam generator (HRSG).