Oxygen lances for electric arc furnaces

Abstract

The utility model discloses a kind of oxygen lances for electric arc furnace steelmaking, including oxygen lance body, the oxygen lance body one side is connected into oxygen pipe, its other side is connected with cluster spray head, the oxygen lance body includes oxygen lance inner tube, middle pipe, water-cooled inner tube and water-cooled outer tube that are coaxially sleeved from inside to outside in order, the oxygen lance inner tube is connected with the oxygen pipe, water baffle is arranged along the axial direction between the water-cooled inner tube and the water-cooled outer tube, the oxygen lance inner tube is connected with the cluster spray head, the water-cooled inner tube and the water-cooled outer tube are sleeved on the outer side of the cluster spray head outer wall and extend outward along the axial direction of the cluster spray head to form combustion chamber, the combustion chamber is radially contracted and has the tapered structure of port along the axial direction of the cluster spray head outward extension direction. The utility model has the advantages of improving oxygen jet penetration and combustion intensity, easy to maintain and replace.

Description

Technical Field

[0001] This utility model belongs to the field of metallurgical equipment technology, and in particular relates to a clustered oxygen lance for electric arc furnace steelmaking. Background Technology

[0002] The clustered oxygen lance used in electric arc furnace steelmaking adds a co-flow of combustion gas around the nozzle of a conventional supersonic oxygen lance. The heat released by the combustion of the gas forms a high-temperature flame that surrounds the central supersonic oxygen jet, thereby suppressing the diffusion and attenuation of the central supersonic oxygen jet. This provides a longer-distance supersonic clustered jet to the molten pool, improving the molten pool dynamics. Simultaneously, the clustered oxygen lance also undertakes smelting tasks such as oxygen blowing to aid melting, creating foamed slag, and homogenizing the composition of the molten steel.

[0003] Existing clustered oxygen lances for electric arc furnace steelmaking include the lance body and the clustered nozzle. The nozzle structure of the clustered nozzle does not have an independent premixed combustion chamber at the nozzle end, which is not conducive to the full mixing and combustion of fuel and oxygen. Some existing clustered nozzles use a straight-tube premixed combustion chamber to improve the combustion effect of fuel and oxygen. Although the clustered nozzles have been appropriately optimized in the existing technology, the oxygen jet penetration is weak and the combustion intensity is low, making them unsuitable for high-intensity decarburization or rapid melting scenarios.

[0004] In addition, most existing cluster oxygen lances have hydrogen and auxiliary oxygen channels formed by drilling holes at the oxygen lance outlet, which cannot be disassembled and provides poor protection for the main oxygen jet.

[0005] Furthermore, existing electric arc furnace steelmaking bundled oxygen lances mostly use natural gas (methane) as fuel, and adjust the methane input flow rate to meet the task requirements of different smelting stages; however, methane combustion produces a large amount of CO2 gas emissions, which is not conducive to achieving low-carbon production in electric arc furnaces.

[0006] Therefore, a new type of clustered oxygen lance structure for electric arc furnace steelmaking is needed, which can use hydrogen as fuel to improve the penetration and combustion intensity of the oxygen jet, while also being easy to maintain and replace. Utility Model Content

[0007] The purpose of this invention is to provide a clustered oxygen lance for electric arc furnace steelmaking that can improve the penetration power and combustion intensity of oxygen jets.

[0008] Another objective of this invention is to provide a detachable cluster oxygen lance for electric arc furnace steelmaking that is easy to maintain and replace.

[0009] Another objective of this invention is to provide a cluster oxygen lance for electric arc furnace steelmaking that can use hydrogen as fuel gas, has high thermal efficiency, high energy density, and clean and renewable fuel gas.

[0010] To achieve the above objectives, this utility model proposes a clustered oxygen lance for electric arc furnace steelmaking, comprising an oxygen lance body, an oxygen inlet pipe connected to one side of the oxygen lance body, and a clustered nozzle connected to the other side. The oxygen lance body includes an oxygen lance inner tube, a middle tube, a water-cooled inner tube, and a water-cooled outer tube coaxially arranged from the inside to the outside. The oxygen lance inner tube is connected to the oxygen inlet pipe. A water baffle is axially arranged between the water-cooled inner tube and the water-cooled outer tube. The oxygen lance inner tube is connected to the clustered nozzle. The water-cooled inner tube and the water-cooled outer tube are fitted onto the outer periphery of the clustered nozzle and extend outward along the axial direction of the clustered nozzle to form a combustion chamber. The combustion chamber has a radially constricted, tapered structure with an end port along the outward extension direction of the axial direction of the clustered nozzle.

[0011] Furthermore, the contraction angle of the combustion chamber is 10° to 30°.

[0012] Furthermore, the side of the middle tube facing the oxygen inlet pipe is detachably connected to the inner tube of the oxygen gun, the side of the water-cooled inner tube facing the oxygen inlet pipe is detachably connected to the middle tube, and the side of the water-cooled outer tube facing the oxygen inlet pipe is detachably connected to the water-cooled inner tube.

[0013] Furthermore, the water-cooled outer pipe is connected to the water outlet pipe, and the water-cooled inner pipe is connected to the water inlet pipe; the water-cooled outer pipe and the water-cooled inner pipe are connected via a first flange on the side facing the oxygen inlet pipe; the water-cooled inner pipe and the middle pipe are connected via a second flange on the side facing the oxygen inlet pipe, and the middle pipe is connected via a third flange on the side facing the oxygen inlet pipe to the oxygen gun inner pipe.

[0014] Furthermore, a first connecting ring is provided at the connection between the water-cooled inner tube and the middle tube; a second connecting ring is provided at the connection between the middle tube and the oxygen lance inner tube.

[0015] Furthermore, within the oxygen lance body, the inner cavity of the oxygen lance inner tube forms a main oxygen channel, the cavity between the oxygen lance inner tube and the middle tube forms a hydrogen channel, the cavity between the middle tube and the water-cooled inner tube forms an epoxy channel, the water-cooled inner tube communicates with the water baffle and the cavity between the water baffle and the water-cooled outer tube to form a water cooling channel, the hydrogen channel is connected to the hydrogen supply pipe, and the epoxy channel is connected to the epoxy supply pipe.

[0016] Furthermore, the cluster nozzle includes a main oxygen Laval tube and a cylindrical built-in copper head. The inlet side of the main oxygen Laval tube is connected to and communicates with the inner tube of the oxygen lance, and the outlet side of the main oxygen Laval tube is connected to and communicates with the combustion chamber. The built-in copper head is fitted between the outer peripheral wall of the main oxygen Laval tube and the water-cooled inner tube and is adjacent to the combustion chamber. Multiple annular hydrogen holes are axially penetrating on the inner wall of the built-in copper head. One end of the annular hydrogen hole is connected to the hydrogen channel, and the other end of the annular hydrogen hole is connected to the combustion chamber. Multiple epoxy holes are axially penetrating on the outer wall of the built-in copper head. One end of the epoxy hole is connected to the epoxy channel, and the other end of the epoxy hole is connected to the combustion chamber. The multiple annular hydrogen holes and the multiple epoxy holes are staggered circumferentially.

[0017] Furthermore, each of the epoxy pores is inclined along the axial direction at an angle of 20° to 30°.

[0018] Furthermore, the cross-sections of both the hydrogen pores and the epoxy pores are semi-circular.

[0019] Furthermore, the main oxygen Laval tube is welded to the inner tube of the oxygen lance, and the built-in copper head is welded to the middle tube.

[0020] This utility model has the following features and advantages: 1. This utility model adopts a converging combustion chamber. The mixed gas is ejected after being compressed and accelerated, and high kinetic energy is used to obtain strong penetrating force, so that the surrounding gas and oxygen are fully mixed and burned to form a high-temperature flame shroud, which enhances the penetration depth and stirring intensity of the main oxygen jet into the molten metal pool and strengthens the electric furnace smelting.

[0021] 2. This utility model uses high-flow-rate hydrogen instead of methane as the fuel gas for the electric arc furnace's cluster jet oxygen lance, reducing the consumption of high-calorific-value fuel gas (such as natural gas), reducing carbon emissions in the steelmaking process, and realizing green and low-carbon production of electric arc furnaces.

[0022] 3. This utility model has a compact structure and adopts a detachable design, making the maintenance and replacement of the oxygen lance convenient and quick.

[0023] 4. This utility model adopts an axial tilt setting, which improves the combustion effect of fuel and oxygen and increases the oxygen utilization rate. Attached Figure Description

[0024] The accompanying drawings described herein are for illustrative purposes only and are not intended to limit the scope of this invention in any way. Furthermore, the shapes and proportions of the components in the drawings are merely illustrative to aid in understanding the invention and do not specifically limit the shapes and proportions of the components. Those skilled in the art, under the guidance of this invention, can select various possible shapes and proportions to implement this invention according to specific circumstances.

[0025] Figure 1 This is a three-dimensional structural schematic diagram of the clustered oxygen lance for electric arc furnace steelmaking according to this utility model; Figure 2 This is a schematic diagram of the axial cross-sectional structure of the clustered oxygen lance for electric arc furnace steelmaking according to this utility model. Figure 3 for Figure 2 An enlarged schematic diagram of the cluster nozzle in section A; Figure 4 for Figure 2 Schematic diagram of the cross-sectional structure along the BB direction; Figure 5 A three-dimensional structural diagram of the built-in copper head of this utility model.

[0026] Explanation of reference numerals in the attached figures: 100-Oxygen lance body, 1-Oxygen inlet pipe, 2-Oxygen lance inner pipe, 3-Middle pipe, 4-Hydrogen supply pipe (fuel gas pipe), 5-Water-cooled inner pipe, 6-Epoxy gas supply pipe, 7-Water baffle, 8-Water-cooled outer pipe, 9-Water outlet pipe. 10-Cluster nozzle, 101-Main oxygen Laval tube, 102-Built-in copper head, 103-Annular hydrogen orifice, 104-Epoxy orifice, 105-Combustion chamber, 106-Reduced diameter section, 107-Throat, 108-Expanding section, 109-Port of combustion chamber 11-Water inlet pipe, 12-First flange, 13-First connecting ring, 14-Second flange, 15-Second connecting ring, 16-Third flange, 17-Bend, 18-Water cooling passage, 19-Hydrogen passage, 20-Main oxygen passage, 21-Epoxy passage. Detailed Implementation

[0027] The details of this utility model can be more clearly understood by referring to the accompanying drawings and the description of specific embodiments. However, the specific embodiments of this utility model described herein are for illustrative purposes only and should not be construed as limiting the utility model in any way. Under the teachings of this utility model, those skilled in the art can conceive of any possible modifications based on this utility model, and these should all be considered to fall within the scope of this utility model.

[0028] like Figure 1 , Figure 2As shown, the bundled oxygen lance for electric arc furnace steelmaking proposed in this utility model includes an oxygen lance body 100 and a bundled nozzle 10. One side of the oxygen lance body 100 is connected to an oxygen inlet pipe 1 for providing main oxygen; the other side of the oxygen lance body 100 is the bundled nozzle 10 for injecting mixed combustion gas. The oxygen lance body 100 includes an inner oxygen lance tube 2, a middle tube 3, a water-cooled inner tube 5, and a water-cooled outer tube 8, coaxially arranged from the inside out, forming a packaged structure. The inner oxygen lance tube 2 is connected to the oxygen inlet pipe 1, allowing the main oxygen supplied externally to be transported to the inner oxygen lance tube 2 through the oxygen inlet pipe 1. Figure 2 , Figure 3 As shown, in this embodiment, the bottom of the water-cooled inner tube 5 is connected to the bottom of the water-cooled outer tube 8. A water baffle 7 is arranged axially in the cavity between the water-cooled inner tube 5 and the water-cooled outer tube 8 to form a meandering water-cooling channel 18, thereby realizing the water-cooling function. The cluster nozzle 10 is connected to the bottom end of the oxygen lance inner tube 2 and communicates with the oxygen lance inner tube 2. The water-cooled inner tube 5 and the water-cooled outer tube 8 are fitted on the outer periphery of the cluster nozzle 10 and extend outward along the axial direction of the cluster nozzle 10 to form a combustion chamber 105. The combustion chamber 105 has a radially contracting structure with an opening 109 along the outward extension direction of the axial direction of the cluster nozzle. That is, the cross-section of the combustion chamber 105 gradually decreases from the side adjacent to the cluster nozzle 10 to the side away from the cluster nozzle 10. This allows the premixed gas ejected from the cluster nozzle 10 to be compressed and accelerated by the gradually contracting combustion chamber 105 and then ejected through the port 109, exchanging high kinetic energy for strong penetration and enhancing the jet penetration.

[0029] As an optional implementation, the contraction angle of the combustion chamber 105 is 10° to 30°, thereby generating better jet penetration. Preferably, the contraction angle of the combustion chamber 105 is set to 20°, which helps to obtain a higher outlet flow rate.

[0030] like Figure 1 , Figure 2As shown, the water-cooled inner tube 5 is connected to the inlet pipe 11, which provides cooling water to the cooling channel 18. The water-cooled outer tube 8 is connected to the outlet pipe 9, and the cooling water is output from the outlet pipe 9 after passing through the cooling channel 18, forming the oxygen lance's cooling system. Specifically, the water-cooled outer tube 8 and the water-cooled inner tube 9 are connected to the oxygen inlet pipe 1 via a first flange 12; the water-cooled inner tube 5 and the middle tube 3 are connected to the oxygen inlet pipe 1 via a second flange 14; and the middle tube 3 is connected to the oxygen lance inner tube 2 via a third flange 16. In this invention, in addition to the flange connections described above, bolt connections, snap-fit ​​connections, tenon joints, and other detachable connection methods can also be used between the middle tube 3 and the oxygen lance inner tube, between the water-cooled inner tube 5 and the middle tube 3, and between the water-cooled outer tube 8 and the water-cooled inner tube 5. That is, any connection method that enables detachable functionality between components falls within the protection scope of this invention. This utility model adopts a detachable design. When the oxygen lance is repaired or replaced, the inner tube 2 and the middle tube 3 of the oxygen lance can be pulled out by removing the corresponding flange, which greatly facilitates the repair and replacement of the oxygen lance.

[0031] Furthermore, a first connecting ring 13 is provided at the connection between the water-cooled inner tube 5 and the middle tube 3; a second connecting ring 15 is provided at the connection between the middle tube 3 and the oxygen lance inner tube 2, thereby enhancing the stability and reliability of the connection between the components.

[0032] like Figure 2 As shown, inside the oxygen lance body 100, the inner cavity of the oxygen lance inner tube 2 forms the main oxygen channel 20, the cavity between the oxygen lance inner tube 2 and the middle tube 3 forms the hydrogen channel 19, the cavity between the middle tube 3 and the water-cooled inner tube 5 forms the epoxy channel 21, and the cavities between the water-cooled inner tube 5 and the water baffle 7, and between the water baffle 7 and the water-cooled outer tube 8, form the water cooling channel 18. The hydrogen channel 19 is connected to the hydrogen supply pipe 4, through which hydrogen is introduced as fuel; the epoxy channel 21 is connected to the epoxy supply pipe 6, through which oxygen is introduced to provide auxiliary oxygen for combustion. In use, the oxygen lance inner tube 2 is connected to the oxygen inlet pipe 1. The main oxygen is introduced into the oxygen lance inner tube 2 through the oxygen inlet pipe 1, the hydrogen fuel enters the hydrogen channel 19 between the oxygen lance inner tube 2 and the middle tube 3 from the hydrogen supply pipe 4, and the auxiliary oxygen enters the epoxy channel 21 between the middle tube 3 and the water-cooled inner tube 5 from the epoxy supply pipe 6.

[0033] Furthermore, such as Figure 2 , Figure 3 , Figure 4As shown, the cluster nozzle 10 includes a main oxygen Laval tube 101 and a cylindrical built-in copper head 102. The inlet side of the main oxygen Laval tube 101 is connected to and communicates with the inner tube 2 of the oxygen lance, and the outlet side of the main oxygen Laval tube 101 is connected to and communicates with the combustion chamber 105, so that the main oxygen in the inner tube 2 of the oxygen lance is injected into the combustion chamber 105 through the main oxygen Laval tube 101 for mixing and combustion. The built-in copper head 102 is fitted between the outer peripheral wall of the main oxygen Laval tube 101 and the water-cooled inner tube 5 and is adjacent to the combustion chamber 105. Multiple annular hydrogen holes 103 are provided axially through the inner wall of the built-in copper head 102. One end of the annular hydrogen hole 103 is connected to the hydrogen channel 19, and the other end of the annular hydrogen hole 103 is connected to the combustion chamber 105, so that hydrogen as fuel gas can be injected into the combustion chamber 105 through the annular hydrogen hole 103 for mixing and combustion. Multiple epoxy holes 104 are axially perforated on the outer wall of the built-in copper head 102. One end of the epoxy hole 104 is connected to the epoxy channel 21, and the other end of the epoxy hole 104 is connected to the combustion chamber 105, so that auxiliary oxygen is injected into the combustion chamber 105 through the epoxy hole 104 for mixing and combustion. Figure 4 , Figure 5 As shown, in an embodiment of this utility model, a plurality of annular hydrogen pores 103 and a plurality of epoxy pores 104 are arranged alternately in the circumferential direction to promote full mixing and combustion of secondary oxygen and hydrogen gas.

[0034] Furthermore, such as Figure 5 As shown, each annular hydrogen orifice 103 is inclined along the axial direction at an angle of 20° to 30°. This allows the epoxy flow to generate a tangential velocity around the oxygen lance axis after passing through the annular hydrogen orifice 103, enhancing the thorough mixing of the epoxy and annular hydrogen fuel, thus promoting the formation of a stable and reliable flame sleeve and achieving a longer main oxygen jet core region. The swirling intensity of the epoxy is dominated by the inclination angle α, and its relationship with the main oxygen jet core length L_core can be expressed as: , Where L_core is the core length of the main oxygen jet; α is the tilt angle of the epoxy orifice; D is the outlet diameter of the main oxygen nozzle; n is an empirical index that reflects the sensitivity of the core length to the swirl intensity, typically 0.8-1.5; and K is a proportionality constant, which is a comprehensive constant that includes the influence of factors such as the flow ratio of the main oxygen jet to the epoxy jet, pressure, density, and environmental gas characteristics.

[0035] If the tilt angle is less than 20°, the swirling flow is too weak. The cyclic hydrogen (fuel gas) and epoxy (oxygen) are mainly ejected in parallel, axial streams. Their mixing relies on turbulent shearing caused by velocity differences, resulting in low mixing efficiency. The protective gas curtain formed by the weak swirling flow is not tight or stable enough, and is easily torn apart by the main oxygen flow or interfered with by the gas flow in the furnace, causing the main oxygen flow to diverge prematurely and the focusing effect to deteriorate. If the tilt angle is greater than 30°, the excessively strong swirling flow will cause the cyclic fuel and epoxy to mix and burn violently in a very short distance. The combustion is too concentrated near the nozzle outlet, resulting in extremely high local temperatures in that area and exacerbating the burn-out of the nozzle tip. In addition, a large tilt angle will cause the jet to become diffused, losing the "rigidity" required to penetrate scrap steel or deep smelting pools. Therefore, the tilt angle of the epoxy orifice 104 should be in the range of 20°-30°.

[0036] Furthermore, such as Figure 4 As shown, the cross-sections of both the annular hydrogen orifice 103 and the epoxy orifice 104 are semi-circular. The diameter of the semi-circular annular hydrogen orifice 103 is 5.5 mm to 8.5 mm, and the diameter of the semi-circular epoxy orifice 104 is 6.5 mm to 9.4 mm. There are 8-12 of each, further promoting thorough mixing and combustion of hydrogen and oxygen. Compared with other existing shapes of annular hydrogen orifices and epoxy orifices, the semi-circular annular hydrogen orifice 103 and epoxy orifice 104 used in this invention have technical advantages in terms of jet characteristics, structural strength, and performance. Regarding jet characteristics: Existing complete circular orifices exhibit a typical axisymmetric "bell-shaped" outlet gas flow distribution, with high velocity at the center and low velocity at the edges. This is not conducive to rapid and thorough, uniform mixing with the main oxygen flow or ambient gas at the outlet, resulting in poor flame envelopment. The biggest drawback of existing rectangular orifices is their sharp corners. Elliptical orifices are superior to rectangular orifices, but areas with small radii of curvature still exist at both ends of the major axis, leading to a certain degree of stress concentration. In contrast, the semi-circular annular hydrogen orifice 103 and epoxy orifice 104 used in this invention create a stronger "wall adhesion effect" and a more uniform lateral velocity distribution on the straight side near the gun body wall. This helps the gases (such as fuel gas or protective oxygen) ejected from multiple semi-circular orifices to merge more quickly into a continuous, stable, and uniform annular gas curtain around the outlet, enhancing the protection of the main oxygen flow.

[0037] Regarding structural strength and performance: Existing complete circular, rectangular, or elliptical holes are drilled using an internal copper head, resulting in stress concentration zones around the nozzle. Under extreme thermal cycling (frequent heating-cooling) and high-pressure loads within the electric furnace, these stress concentration points are prone to microcracks, ultimately leading to material cracking and burning between the holes. This invention, however, utilizes semi-circular holes on the inner and outer walls of the internal copper head 102. This structure maintains the radial continuity of the internal copper head structure, significantly improves stress distribution, extends the overall service life of the oxygen lance body, and facilitates disassembly and maintenance.

[0038] Furthermore, the main oxygen Laval tube 101 is welded to the oxygen lance inner tube 2, and the built-in copper head 102 is also welded to the middle tube 3, ensuring the airtightness and structural strength of the connection. For example, Figure 3 As shown, the main oxygen Laval tube 101 includes a reduced-diameter section 106, a throat 107, and an expanded section 108 connected in sequence; the diameter of the throat 107 is determined according to the design flow rate, and the outlet diameter of the expanded section 108 is determined according to the required Mach number. In an optional embodiment, the design flow rate of the main oxygen Laval tube 101 is 2800 Nm³. 3 / h, Mach number 2.0. The semi-circular annular hydrogen pores 103 have a diameter of 6.0 mm, and the semi-circular epoxy pores 104 have a diameter of 7.5 mm. They are staggered and there are 10 of each. The semi-circular epoxy pores 104 adopt an axially inclined through-hole design with an inclination angle of 10°. This design promotes the full mixing and combustion of epoxy and annular hydrogen gases.

[0039] The detailed explanations of the above embodiments are intended only to explain the present invention so as to facilitate a better understanding of the present invention. However, these descriptions should not be construed as limiting the present invention for any reason. In particular, the various features described in different embodiments can be arbitrarily combined with each other to form other embodiments. Unless there is an explicit description to the contrary, these features should be understood to be applicable to any embodiment, and not limited to the described embodiments.

Claims

1. A clustered oxygen lance for electric arc furnace steelmaking, comprising an oxygen lance body, wherein one side of the oxygen lance body is connected to an oxygen inlet pipe and the other side is connected to a clustered nozzle, characterized in that, The oxygen lance body includes an oxygen lance inner tube, a middle tube, a water-cooled inner tube, and a water-cooled outer tube, which are coaxially sleeved from the inside to the outside. The oxygen lance inner tube is connected to the oxygen inlet pipe. A water baffle is arranged axially between the water-cooled inner tube and the water-cooled outer tube. The oxygen lance inner tube is connected to the cluster nozzle. The water-cooled inner tube and the water-cooled outer tube are fitted onto the outer periphery of the cluster nozzle and extend outward along the axial direction of the cluster nozzle to form a combustion chamber. The combustion chamber has a radially constricted, tapered structure with an end port along the outward extension direction of the axial direction of the cluster nozzle.

2. The clustered oxygen lance for electric arc furnace steelmaking as described in claim 1, characterized in that, The contraction angle of the combustion chamber is 10° to 30°.

3. The clustered oxygen lance for electric arc furnace steelmaking as described in claim 1, characterized in that, The middle tube is detachably connected to the oxygen lance inner tube on the side facing the oxygen inlet pipe, the water-cooled inner tube is detachably connected to the middle tube on the side facing the oxygen inlet pipe, and the water-cooled outer tube is detachably connected to the water-cooled inner tube on the side facing the oxygen inlet pipe.

4. The clustered oxygen lance for electric arc furnace steelmaking as described in claim 3, characterized in that, The water-cooled outer pipe is connected to the water outlet pipe, and the water-cooled inner pipe is connected to the water inlet pipe; the water-cooled outer pipe and the water-cooled inner pipe are connected by a first flange on the side facing the oxygen inlet pipe; the water-cooled inner pipe and the middle pipe are connected by a second flange on the side facing the oxygen inlet pipe, and the middle pipe is connected by a third flange on the side facing the oxygen inlet pipe to the oxygen gun inner pipe.

5. The clustered oxygen lance for electric arc furnace steelmaking as described in claim 4, characterized in that, A first connecting ring is provided at the connection between the water-cooled inner tube and the middle tube; a second connecting ring is provided at the connection between the middle tube and the oxygen lance inner tube.

6. The clustered oxygen lance for electric arc furnace steelmaking as described in any one of claims 1 to 5, characterized in that, Within the oxygen lance body, the inner cavity of the oxygen lance inner tube forms the main oxygen channel, the cavity between the oxygen lance inner tube and the middle tube forms the hydrogen channel, the cavity between the middle tube and the water-cooled inner tube forms the epoxy channel, the cavity between the water-cooled inner tube and the water baffle plate and the cavity between the water baffle plate and the water-cooled outer tube forms the water cooling channel, the hydrogen channel is connected to the hydrogen supply pipe, and the epoxy channel is connected to the epoxy supply pipe.

7. The clustered oxygen lance for electric arc furnace steelmaking as described in claim 6, characterized in that, The cluster nozzle includes a main oxygen Laval tube and a cylindrical built-in copper head. The inlet side of the main oxygen Laval tube is connected to and communicates with the inner tube of the oxygen lance, and the outlet side of the main oxygen Laval tube is connected to and communicates with the combustion chamber. The built-in copper head is fitted between the outer peripheral wall of the main oxygen Laval tube and the water-cooled inner tube and is adjacent to the combustion chamber. Multiple annular hydrogen holes are axially penetrating on the inner wall of the built-in copper head. One end of the annular hydrogen hole is connected to the hydrogen channel, and the other end of the annular hydrogen hole is connected to the combustion chamber. Multiple epoxy holes are axially penetrating on the outer wall of the built-in copper head. One end of the epoxy hole is connected to the epoxy channel, and the other end of the epoxy hole is connected to the combustion chamber. The multiple annular hydrogen holes and the multiple epoxy holes are arranged alternately in the circumferential direction.

8. The clustered oxygen lance for electric arc furnace steelmaking as described in claim 7, characterized in that, Each of the epoxy pores is inclined along the axial direction at an angle of 20° to 30°.

9. The clustered oxygen lance for electric arc furnace steelmaking as described in claim 8, characterized in that, Both the hydrogen pores and the epoxy pores have semi-circular cross-sections.

10. The clustered oxygen lance for electric arc furnace steelmaking as described in claim 7, characterized in that, The main oxygen Laval tube is welded to the inner tube of the oxygen lance, and the built-in copper head is welded to the middle tube.

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