# US 11,309,553 B2 · Fuel cell system including exhaust heat recovery components > Agents: this data is available as JSON from the patentgrep API and MCP server — see https://patentgrep.com/llms.txt - Number: US 11,309,553 B2 - Document ID: US11309553B2 - Status: Granted - Kind: B2 - Application number: 16/724,991 - Filed: 2019-12-23 - Published: 2020-07-02 - Granted: 2022-04-19 - Earliest claimed: 2018-12-26 - Assignees: Bloom Energy Corporation - Applicants: Bloom Energy Corporation - Inventors: Arne Ballantine; Jessica Mahler; Swaminathan Venkataraman; Martin Perry; David Weingaertner; Samuel Juday; Christian Daco - Web page: https://patentgrep.com/patent/US11309553B2 ## CPC - H01M 8/04074: {Heat exchange unit structures specially adapted for fuel cell} - H01M 8/04014: Heat exchange using gaseous fluids; Heat exchange by combustion of reactants - H01M 8/04097: {with recycling of the reactants (H01M8/04119, H01M8/04104 take precedence)} - H01M 8/04701: Temperature - H01M 8/0631: {Reactor construction specially adapted for combination reactor/fuel cell (hydrogen C01B3/00; reactors for physicochemical processes B01J19/00)} - H01M 8/0668: Removal of carbon monoxide or carbon dioxide - H01M 8/0675: {Removal of sulfur} - H01M 8/2475: Enclosures, casings or containers of fuel cell stacks - H01M 2004/8684: {Negative electrodes} - Y02E 60/50: Fuel cells - H01M: PROCESSES OR MEANS, e.g. BATTERIES, FOR THE DIRECT CONVERSION OF CHEMICAL ENERGY INTO ELECTRICAL ENERGY - Y02E: REDUCTION OF GREENHOUSE GAS [GHG] EMISSIONS, RELATED TO ENERGY GENERATION, TRANSMISSION OR DISTRIBUTION ## Abstract A fuel cell system including power modules including fuel cells, and an exhaust flue connected to the power modules. The exhaust flue includes an outer duct configured to receive relatively cool cabinet exhaust from the power modules, and an inner duct disposed inside of the outer duct and configured to receive relatively hot reaction exhaust from the power modules. ## Claims ### Claim 1 A fuel cell system comprising: power modules that each comprise a cabinet and fuel cells disposed in the cabinet; and an exhaust flue comprising: an outer duct configured to receive relatively cool cabinet exhaust output from the cabinets; and an inner duct disposed inside of the outer duct and configured to receive relatively hot reaction exhaust output from the fuel cells of the power modules. ### Claim 2 (depends on 1) The system of claim 1, further comprising a heat exchanger located in the exhaust flue and configured to extract heat from the reaction exhaust. ### Claim 3 (depends on 2) The system of claim 2, wherein the heat exchanger comprises a boiler. ### Claim 4 (depends on 2) The system of claim 2, further comprising: a damper configured to divert at least a portion of the reaction exhaust from the inner duct into the outer duct; and an actuator configured to open and close the damper. ### Claim 5 (depends on 1) The system of claim 1, further comprising: a reaction conduit extending through the outer duct and the inner duct and configured to provide fuel from a fuel source to at least one of the power modules; a first catalyst disposed in the reaction conduit; and a second catalyst disposed in the reaction conduit downstream from the first catalyst, with respect to a flow direction of a fuel through the reaction conduit. ### Claim 6 (depends on 5) The system of claim 5, wherein: the first catalyst comprises a metal oxide catalyst configured to remove sulfur species from the fuel; and the second catalyst comprises a reformation or methanation catalyst. ### Claim 7 (depends on 5) The system of claim 5, further comprising: a carbon dioxide separator disposed on the reaction conduit, outside of the flue, and downstream of the second catalyst; and a heat exchanger disposed on the reaction conduit, in the outer duct, and downstream of the second catalyst. ### Claim 8 (depends on 7) The system of claim 7, further comprising: a flow control valve disposed on the reaction conduit, outside of the flue, and upstream of the first catalyst; and an anode recirculation blower disposed on the reaction conduit, outside of the exhaust flue, and downstream of the heat exchanger. ### Claim 9 (depends on 1) The system of claim 1, further comprising a thermoelectric generator module disposed between the inner duct and the outer duct. ### Claim 10 (depends on 1) The system of claim 1, wherein the exhaust flue comprises a plurality of the inner ducts disposed in the outer duct. ### Claim 11 (depends on 1) The system of claim 1, wherein the power modules are disposed in vertically stacked rows, and wherein the exhaust flue is located between back sides of two rows of the power modules. ### Claim 12 (depends on 1) The system of claim 1, wherein: the fuel cells are located in hot boxes; and the hot boxes are located inside cabinets of the power modules. ### Claim 13 (depends on 12) The system of claim 12, wherein the inner duct is fluidly connected to exhaust conduits of the hot boxes. ### Claim 14 (depends on 13) The system of claim 13, wherein the outer duct is fluidly connected to exhaust conduits of the cabinets. ### Claim 15 A method of operating a fuel cell system, comprising: operating fuel cells located in hot boxes which are located inside cabinets to generate electricity; providing a relatively cool cabinet exhaust from the cabinets to an outer duct of a flue; and providing a relatively hot reaction exhaust from the hot boxes to an inner duct of the flue that is disposed inside of the outer duct. ### Claim 16 (depends on 15) The method of claim 15, further comprising extracting heat from the reaction exhaust in a heat exchanger located in the inner duct. ### Claim 17 (depends on 15) The method of claim 15, further comprising opening a damper to divert at least a portion of the reaction exhaust from the inner duct into the outer duct. ### Claim 18 (depends on 15) The method of claim 15, further comprising at least one of reforming, desulfurizing, methanating or fractionating a hydrocarbon fuel in a reaction conduit located in the inner duct using heat from the reaction exhaust flowing through the inner duct. ### Claim 19 (depends on 15) The method of claim 15, wherein the relatively cool cabinet exhaust from the cabinets flows in the outer duct of a flue in a same direction as the relatively hot reaction exhaust from the hot boxes flows in the inner duct of the flue.