Auxiliary burner for electric furnace

Patent metadata

Field	Value
Publication number	US-10935234-B2
Application number	US-201716320217-A
Country	US
Kind code	B2
Filing date	Jul 24, 2017
Priority date	Jul 26, 2016
Publication date	Mar 2, 2021
Grant date	Mar 2, 2021

Abstract

Provided is an auxiliary burner for an electric furnace capable of increasing and homogenizing the heating effect of iron scrap by suitably and efficiently burning solid fuel along with gas fuel. This auxiliary burner 100 for an electric furnace comprises a solid fuel injection tube 1, a gas fuel injection tube 2, and a combustion-supporting gas injection tube 3 in the stated order from the center side, all arranged coaxially, and is characterized in that: a flow path 30 of the combustion-supporting gas injection tube 3 is provided with a plurality of swirl vanes 4 for swirling the combustion-supporting gas, and a flow path 20 of the gas fuel injection tube 2 is provided with a plurality of swirl vanes 5 for swirling the gas fuel; and the angle θ1 of the swirl vanes 4 and the θ2 of the swirl vanes 5 satisfy the relationship θ1<θ2.

First claim

The invention claimed is:

1. An auxiliary burner for an electric furnace for manufacturing molten iron by melting iron scrap, which is attached to the electric furnace and uses a gas fuel and a solid fuel as fuel, comprising:
a solid fuel injection tube defining a first flow path through which the solid fuel passes and configured to inject the solid fuel from a tip of the first flow path;
a gas fuel injection tube arranged around the solid fuel injection tube, defining a second flow path through which the gas fuel passes between the gas fuel injection tube and an outer wall of the solid fuel injection tube, and configured to inject the gas fuel from a tip of the second flow path;
a combustion-supporting gas injection tube arranged around the gas fuel injection tube, defining a third flow path through which a combustion-supporting gas passes between the combustion-supporting gas injection tube and an outer wall of the gas fuel injection tube, and configured to inject the combustion-supporting gas from a tip of the third flow path;
a plurality of first vanes arranged in the third flow path at a predetermined interval in a circumferential direction of the third flow path; and
a plurality of second vanes arranged in the second flow path at a predetermined interval in a circumferential direction of the second flow path, wherein
the plurality of first vanes form an angle θ 1 with a burner axis and the plurality of second vanes form an angle θ 2 with the burner axis, the angles satisfying a relationship θ 1 <θ 2 , and the angle θ 1 is 10° or more and 50° or less, and the angle θ 2 is 20° or more and 75° or less.

2. An auxiliary burner for an electric furnace for manufacturing molten iron by melting iron scrap, which is attached to the electric furnace and uses a gas fuel and a solid fuel as fuel, comprising:
a solid fuel injection tube defining a first flow path through which the solid fuel passes and configured to inject the solid fuel from a tip of the first flow path;
a gas fuel injection tube arranged around the solid fuel injection tube, defining a second flow path through which the gas fuel passes between the gas fuel injection tube and an outer wall of the solid fuel injection tube, and configured to inject the gas fuel from a tip of the second flow path;
a combustion-supporting gas injection tube arranged around the gas fuel injection tube, defining a third flow path through which a combustion-supporting gas passes between the combustion-supporting gas injection tube and an outer wall of the gas fuel injection tube, and configured to inject the combustion-supporting gas from a tip of the third flow path;
a plurality of first vanes arranged in the third flow path at a predetermined interval in a circumferential direction of the third flow path; and
a plurality of second vanes arranged in the second flow path at a predetermined interval in a circumferential direction of the second flow path, wherein
the plurality of first vanes form an angle 01 with a burner axis and the plurality of second vanes form an angle 02 with the burner axis, the angles satisfying a relationship θ 1 <θ 2 , wherein
θ 2 −θ 1 is 15° or more and 45° or less.

3. The auxiliary burner for an electric furnace according to claim 1 , wherein
θ 2 −θ 1 is 15° or more and 45° or less.

4. The auxiliary burner for an electric furnace according to claim 1 , wherein
when each of the first vanes has a length Q 1 in the circumferential direction of the third flow path and the plurality of first vanes have an installation interval P 1 in the circumferential direction of the third flow path, Q 1 /P 1 is 1.0 or more and 1.2 or less; and
when each of the second vanes has a length Q 2 in the circumferential direction of the second flow path and the plurality of second vanes have an installation interval P 2 in the circumferential direction of the second flow path, Q 2 /P 2 is 1.0 or more and 1.2 or less.

5. The auxiliary burner for an electric furnace according to claim 2 , wherein
when each of the first vanes has a length Q 1 in the circumferential direction of the third flow path and the plurality of first vanes have an installation interval P 1 in the circumferential direction of the third flow path, Q 1 /P 1 is 1.0 or more and 1.2 or less; and
when each of the second vanes has a length Q 2 in the circumferential direction of the second flow path and the plurality of second vanes have an installation interval P 2 in the circumferential direction of the second flow path, Q 2 /P 2 is 1.0 or more and 1.2 or less.

6. The auxiliary burner for an electric furnace according to claim 3 , wherein
when each of the first vanes has a length Q 1 in the circumferential direction of the third flow path and the plurality of first vanes have an installation interval P 1 in the circumferential direction of the third flow path, Q 1 /P 1 is 1.0 or more and 1.2 or less; and
when each of the second vanes has a length Q 2 in the circumferential direction of the second flow path and the plurality of second vanes have an installation interval P 2 in the circumferential direction of the second flow path, Q 2 /P 2 is 1.0 or more and 1.2 or less.

7. An auxiliary burner for an electric furnace for manufacturing molten iron by melting iron scrap, which is attached to the electric furnace and uses a gas fuel and a solid fuel as fuel, comprising:
a solid fuel injection tube defining a first flow path through which the solid fuel passes and configured to inject the solid fuel from a tip of the first flow path;
a gas fuel injection tube arranged around the solid fuel injection tube, defining a second flow path through which the gas fuel passes between the gas fuel injection tube and an outer wall of the solid fuel injection tube, and configured to inject the gas fuel from a tip of the second flow path;
a combustion-supporting gas injection tube arranged around the gas fuel injection tube, defining a third flow path through which a combustion-supporting gas passes between the combustion-supporting gas injection tube and an outer wall of the gas fuel injection tube, and configured to inject the combustion-supporting gas from a tip of the third flow path;
a plurality of first vanes arranged in the third flow path at a predetermined interval in a circumferential direction of the third flow path; and
a plurality of second vanes arranged in the second flow path at a predetermined interval in a circumferential direction of the second flow path, wherein
the plurality of first vanes form an angle θ 1 with a burner axis and the plurality of second vanes form an angle θ 2 with the burner axis, the angles satisfying a relationship θ 1 <θ 2 , wherein
the angle θ 1 is 0°, and the angle θ 2 is 10° or more and 70° or less.

8. The auxiliary burner for an electric furnace according to claim 7 , wherein
the angle θ 2 is 45° or more and 60° or less.

9. The auxiliary burner for an electric furnace according to claim 7 , wherein
when each of the second vanes has a length Q 2 in the circumferential direction of the second flow path and the plurality of second vanes have an installation interval P 2 in the circumferential direction of the second flow path, Q 2 /P 2 is 1.0 or more and 1.2 or less.

10. The auxiliary burner for an electric furnace according to claim 8 , wherein
when each of the second vanes has a length Q 2 in the circumferential direction of the second flow path and the plurality of second vanes have an installation interval P 2 in the circumferential direction of the second flow path, Q 2 /P 2 is 1.0 or more and 1.2 or less.

Assignees

• Jfe Steel Corp
• Chugai Ro Kogyo Kaisha Ltd

Inventors

• Tsutsumi Koichi
• Miwa Yoshihiro
• Ozawa Sumito
• Sumi Ikuhiro
• Tomozawa Kenichi
• Ito Takayuki

Classifications

• F23D99/004

  for use in particular heating operations · CPC title

• F23D17/00

  Burners for combustion simultaneously or alternately of gaseous or liquid or pulverulent fuel · CPC title

• F23D14/24

  at least one of the fluids being submitted to a swirling motion · CPC title

• F23C1/12 Primary

  gaseous and pulverulent fuel · CPC title

• F27D7/02

  Supplying steam, vapour, gases or liquids · CPC title