# US 2023/0054425 A1 · Radiant tube burner, radiant tube, and method of designing radiant tube burner > Agents: this data is available as JSON from the patentgrep API and MCP server — see https://patentgrep.com/llms.txt - Number: US 2023/0054425 A1 - Document ID: US20230054425A1 - Status: Published application - Kind: A1 - Application number: 17/797,269 - Filed: 2021-02-03 - Published: 2023-02-23 - Earliest claimed: 2020-02-10 - Assignees: Jfe Steel Corporation - Applicants: JFE Steel Corporation - Inventors: Tomoyuki Kawashima; Akihiro Kobayashi; Noriko Ozawa - Web page: https://patentgrep.com/patent/US20230054425A1 ## CPC - F23D 14/22: with separate air and gas feed ducts, e.g. with ducts running parallel or crossing each other - F23C 3/002: {the chamber having an elongated tubular form, e.g. for a radiant tube} - F23D 14/12: Radiant burners - F23D 14/58: characterised by the shape or arrangement of the outlet or outlets from the nozzle, e.g. of annular configuration - F23L 1/02: by discharging the air below the fire - F23L 3/00: Arrangements of valves or dampers before the fire - F23L 9/06: by discharging the air into the fire bed - F23L 15/04: Arrangements of recuperators - F23D 2900/14003: with more than one nozzle - F23D 2900/14064: Burner heads of non circular shape - Y02E 20/34: Indirect CO2mitigation, i.e. by acting on non CO2directly related matters of the process, e.g. pre-heating or heat recovery - F23D: BURNERS - F23C: METHODS OR APPARATUS FOR COMBUSTION USING FLUID FUEL OR SOLID FUEL SUSPENDED IN {A CARRIER GAS OR} AIR (burners F23D) - F23L: SUPPLYING AIR OR NON-COMBUSTIBLE LIQUIDS OR GASES TO COMBUSTION APPARATUS IN GENERAL ({air-supply arrangements for fluent fuels F23C;} firebridges with means for feeding air or steam F23M3/04; baffles or shields with air supply passages F23M9/04); VALVES OR DAMPERS SPECIALLY ADAPTED FOR CONTROLLING AIR SUPPLY OR DRAUGHT IN COMBUSTION APPARATUS {(dampers and throat restrictors for open fire-places F24; air inlet valves for open fire fronts F24)}; INDUCING DRAUGHT IN COMBUSTION APPARATUS; TOPS FOR CHIMNEYS OR VENTILATING SHAFTS; TERMINALS FOR FLUES - Y02E: REDUCTION OF GREENHOUSE GAS [GHG] EMISSIONS, RELATED TO ENERGY GENERATION, TRANSMISSION OR DISTRIBUTION ## Abstract A radiant tube burner, wherein an opening cross section of the tube is virtually divided into four areas with two straight lines as boundaries, the two straight lines being obtained by tilting a minor axis of the oval, which is a shape of the opening cross section, by ±45° with a center of the oval as a center, and a flow rate of primary combustion air injected from primary combustion air nozzles located in the areas containing the minor axis of the oval of the virtually divided four areas is lower than a flow rate of the primary combustion air injected from the primary combustion air nozzles located in the areas not containing the minor axis of the oval the four areas. ## Claims ### Claim at position 1 1-5. (canceled) ### Claim 6 A radiant tube burner adapted to be inserted and installed in a tube having an oval-shaped opening cross section and which has a gas injection unit having a secondary combustion air nozzle injecting secondary combustion air arranged in a center portion and a plurality of primary combustion air nozzles injecting primary combustion air and a plurality of fuel gas nozzles injecting fuel gas arranged to surround the secondary combustion air nozzle, wherein the opening cross section of the tube is virtually divided into four areas with two straight lines as boundaries, the two straight lines being obtained by tilting a minor axis of the oval, which is a shape of the opening cross section, by ±45° with a center of the oval as a center, and a flow rate of the primary combustion air injected from the primary combustion air nozzles located in the areas containing the minor axis of the oval of the virtually divided four areas is lower than a flow rate of the primary combustion air injected from the primary combustion air nozzles located in the areas not containing the minor axis of the oval the four areas. ### Claim 7 (depends on 6) The radiant tube burner according to claim 6, wherein, when a short diameter of the oval is defined as La and a long diameter orthogonal to the short diameter is defined as Lb, a flow rate ratio (mt/mx) is set to be equal to or larger than La2/(La2+Lb2), the flow rate ratio (mt/mx) being a ratio of a flow rate mt of the primary combustion air injected from the primary combustion air nozzles located in the areas containing the minor axis to a total air quantity mx of the primary combustion air injected from all of the primary combustion air nozzles. ### Claim 8 (depends on 6) The radiant tube burner according to claim 6, wherein the flow rate of the primary combustion air injected from the primary combustion air nozzles is adjusted by reducing a total opening cross-sectional area of the primary combustion air nozzles located in the areas containing the minor axis to be smaller than a total opening cross-sectional area of the primary combustion air nozzles located in the areas not containing the minor axis of the oval. ### Claim 9 (depends on 7) The radiant tube burner according to claim 7, wherein the flow rate of the primary combustion air injected from the primary combustion air nozzles is adjusted by reducing a total opening cross-sectional area of the primary combustion air nozzles located in the areas containing the minor axis to be smaller than a total opening cross-sectional area of the primary combustion air nozzles located in the areas not containing the minor axis of the oval. ### Claim 10 (depends on 6) A radiant tube comprising: the radiant tube burner according to claim 6, wherein an opening cross section of the tube is formed in an oval shape. ### Claim 11 (depends on 7) A radiant tube comprising: the radiant tube burner according to claim 7, wherein an opening cross section of the tube is formed in an oval shape. ### Claim 12 (depends on 8) A radiant tube comprising: the radiant tube burner according to claim 8, wherein an opening cross section of the tube is formed in an oval shape. ### Claim 13 (depends on 9) A radiant tube comprising: the radiant tube burner according to claim 9, wherein an opening cross section of the tube is formed in an oval shape. ### Claim 14 A method of designing a radiant tube burner adapted to be inserted and installed in a tube having an oval-shaped opening cross section and which has a gas injection unit having a secondary combustion air nozzle injecting secondary combustion air arranged in a center portion and a plurality of primary combustion air nozzles injecting primary combustion air and a plurality of fuel gas nozzles injecting fuel gas arranged to surround the secondary combustion air nozzle, the method comprising: virtually dividing the opening cross section of the tube into four areas with two straight lines as boundaries, the two straight lines being obtained by tilting a minor axis of the oval, which is a shape of the opening cross section, by ±45° with a center of the oval as a center; and when a short diameter of the oval is defined as La and a long diameter orthogonal to the short combustion diameter is defined as Lb, setting an amount of the primary combustion air blown out from each of the primary combustion air nozzles such that a flow rate ratio (mt/mx) satisfies Equation (1), the flow rate ratio (mt/mx) being a ratio of a flow rate mt of the primary combustion air injected from the primary combustion air nozzles located in the areas containing the minor axis to a total air quantity mx of the primary combustion air injected from all of the primary combustion air nozzles, La2/(La2+Lb2)≤(mt/mx)<0.5 (1).