A combustion device is installed in a furnace, is configured to inject and burn ammonia as a fuel, and includes an inner tube nozzle disposed in a center part of the combustion device when viewed in an injection direction of the fuel, and configured to inject the ammonia, and an outer tube nozzle disposed to surround the inner tube nozzle from outside in a radial direction when viewed in the injection direction of the fuel, and configured to inject the ammonia around the inner tube nozzle.

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 .sub.1 of the swirl vanes 4 and the .sub.2 of the swirl vanes 5 satisfy the relationship .sub.1<.sub.2.

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 .sub.1 of the swirl vanes 4 and the .sub.2 of the swirl vanes 5 satisfy the relationship .sub.1<.sub.2.

A wall-fired burner includes a fuel tip defining a fuel direction axis and a fuel tip pivot axis perpendicular thereto. A first air tip is adjacent to the fuel tip. The first air tip defines a first air direction axis and a first air tip pivot axis perpendicular thereto. A second air tip is adjacent to the fuel tip, opposite from the first air tip across the fuel tip. The second air tip defines a second air direction axis and a second air tip pivot axis perpendicular thereto. A mechanism operatively connects the fuel tip, the first air tip and the second air tip for at least one of independent and/or joint movement of the fuel tip, the first air tip and the second air tip.

A wall-fired burner includes a fuel tip defining a fuel direction axis and a fuel tip pivot axis perpendicular thereto. A first air tip is adjacent to the fuel tip. The first air tip defines a first air direction axis and a first air tip pivot axis perpendicular thereto. A second air tip is adjacent to the fuel tip, opposite from the first air tip across the fuel tip. The second air tip defines a second air direction axis and a second air tip pivot axis perpendicular thereto. A mechanism operatively connects the fuel tip, the first air tip and the second air tip for at least one of independent and/or joint movement of the fuel tip, the first air tip and the second air tip.

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 presently disclosed 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 combustion-supporting gas 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 the angle formed between the swirl vanes 4 and the burner axis is 5 or more and 45 or less.

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 presently disclosed 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 combustion-supporting gas 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 the angle formed between the swirl vanes 4 and the burner axis is 5 or more and 45 or less.

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 .sub.1 of the swirl vanes 4 and the .sub.2 of the swirl vanes 5 satisfy the relationship .sub.1<.sub.2.

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 .sub.1 of the swirl vanes 4 and the .sub.2 of the swirl vanes 5 satisfy the relationship .sub.1<.sub.2.

Provided is an auxiliary burner for an electric furnace that has high iron scrap heating effect by appropriately and efficiently burning a solid fuel such as coal together with a gas fuel. An auxiliary burner for an electric furnace 100 has a structure in which a solid fuel injection tube 1, a gas fuel injection tube 2, and a combustion-supporting gas injection tube 3 are coaxially arranged in order from the center. The front end of the solid fuel injection tube 1 is located inside the gas fuel injection tube 2 to form, between the front end of the solid fuel injection tube 1 and the front end of the gas fuel injection tube 2, a first space 4 for solid fuel and gas fuel premixing surrounded by the front end portion of the gas fuel injection tube 2.