Biomass oxygen lance and electric arc furnace

Abstract

The invention provides a biomass oxygen lance and an electric arc furnace, relates to the technical field of metallurgical equipment, and aims at solving the problem that a large amount of carbon is discharged due to the fact that oil oxygen and gas burners are used for fluxing waste steel at the present stage to a certain extent. The invention provides a biomass oxygen lance. The biomass oxygen lance comprises a central pipe, a rotational flow blade and a circular seam sleeve assembly, the central pipe, the rotational flow blade and the circular seam sleeve assembly are sequentially and coaxially arranged in a sleeving mode from inside to outside, a containing cavity is formed in the circular seam sleeve assembly, the central pipe is arranged in the containing cavity, and the rotational flow blade surrounds the outer wall of the central pipe, so that a rotational flow gas channel is formed between the central pipe and the circular seam sleeve assembly; a premixing channel is formed in the position, corresponding to the circular seam sleeve assembly, of the outlet end of the center pipe, and the rotational flow gas channel is communicated with the premixing channel.

Description

Technical Field

[0001] This invention relates to the field of metallurgical equipment technology, and in particular to a biomass oxygen lance and electric arc furnace. Background Technology

[0002] In electric arc furnace steelmaking, three-phase AC electric arc furnaces typically create three cold zones in the furnace wall area during operation, leading to uneven heating of scrap steel and low melting efficiency, thus prolonging the smelting cycle. To improve production efficiency, existing technologies generally use oil-oxygen burners or gas burners to assist in the melting of scrap steel, accelerating energy input and shortening melting time. However, both fuel oil and natural gas combustion processes are accompanied by significant carbon emissions, which contradicts the current green development goal of the metallurgical industry to promote near-zero carbon emissions.

[0003] Biomass energy, as a renewable and carbon-neutral energy form, especially forest biomass (such as sawdust and waste branches), has a high calorific value and can theoretically replace fossil fuels. However, biomass fuels themselves have high volatile matter and low density, and directly using traditional oil-oxygen or gas burner structures can easily lead to unstable combustion, poor flame morphology, and low combustion efficiency. Currently, the metallurgical industry lacks an oxygen lance structure that can be optimized for the characteristics of biomass fuels, making it difficult to achieve efficient and stable combustion of biomass in electric arc furnace smelting.

[0004] Therefore, there is an urgent need to provide a biomass oxygen lance and electric arc furnace to solve the problems existing in the current technology to a certain extent. Summary of the Invention

[0005] The purpose of this invention is to provide a biomass oxygen lance and electric arc furnace to solve, to some extent, the problem of large carbon emissions caused by the current use of oil-oxygen and gas burners to flux scrap steel.

[0006] The present invention provides a biomass oxygen lance, comprising a central tube, swirl vanes, and an annular slit sleeve assembly; the central tube, the swirl vanes, and the annular slit sleeve assembly are coaxially sleeved from the inside out, the annular slit sleeve assembly forms a receiving cavity, the central tube is disposed in the receiving cavity, and the swirl vanes surround the outer wall of the central tube, forming a swirling gas channel between the central tube and the annular slit sleeve assembly; a premixing channel is formed at the outlet end of the central tube corresponding to the position of the annular slit sleeve assembly, and the swirling gas channel is connected to the premixing channel.

[0007] The biomass oxygen gun provided in this application also includes a cooling water jacket, which is disposed outside the annular sleeve assembly and is coaxially arranged with the annular sleeve assembly.

[0008] Specifically, the annular sleeve assembly includes an oxygen annular sleeve and a natural gas annular sleeve; the natural gas annular sleeve is sleeved outside the swirl blade, and the oxygen annular sleeve is sleeved outside the natural gas annular sleeve.

[0009] Furthermore, the inlet ends of both the oxygen annular sleeve and the natural gas annular sleeve are annular, and the outlet ends of both the oxygen annular sleeve and the natural gas annular sleeve are gas outlets, which are evenly distributed circumferentially.

[0010] Furthermore, the outlet direction of the gas outlet of the natural gas annular sleeve forms an angle of 45°-70° with the axis of the central tube, and the outlet direction of the gas outlet of the oxygen annular sleeve forms an angle of 0°-30° with the axis of the central tube. The gas outlets of the natural gas annular sleeve and the oxygen annular sleeve are staggered in the axial direction of the central tube.

[0011] The width of the swirling blades is the same as the gap distance of the swirling air channel. Multiple swirling blades are evenly distributed along the circumference of the central tube on the outer wall of the central tube. The outlet direction of the swirling blades forms an angle of 30°-45° with the axis.

[0012] Specifically, the outlet end of the central tube is provided with a blunt body, which is connected to the edge of the outlet end of the central tube by multiple support columns, and the maximum inner diameter of the blunt body is larger than the inner diameter of the central tube. The blunt body is located directly in front of the outlet end of the central tube.

[0013] Furthermore, the cooling water jacket includes an inlet annular gap and a return annular gap. One end of the inlet annular gap is the inlet end, and the other end is connected to one end of the return annular gap. The other end of the return annular gap is the outlet end, and the outlet end of the return annular gap and the inlet end of the inlet annular gap are located at the same end of the biomass oxygen gun.

[0014] Furthermore, the inlet annular seam is located outside the annular sleeve assembly, and the return annular seam is located outside the inlet annular seam.

[0015] Compared with existing technologies, the biomass oxygen gun provided by this invention has the following advantages: The biomass oxygen lance provided by this invention includes a central tube, swirl vanes, and an annular slit sleeve assembly. The central tube, swirl vanes, and annular slit sleeve assembly are coaxially arranged from the inside to the outside. The annular slit sleeve assembly forms a receiving cavity, and the central tube is disposed in the receiving cavity. The swirl vanes surround the outer wall of the central tube, so that a swirling gas channel is formed between the central tube and the annular slit sleeve assembly. A premixing channel is formed at the outlet end of the central tube corresponding to the position of the annular slit sleeve assembly, and the swirling gas channel is connected to the premixing channel.

[0016] Analysis shows that the layout of the central tube, swirl blades, and annular sleeve assembly, coaxially arranged from the inside out, can ensure efficient and stable combustion of biomass fuel to a certain extent. Specifically, the central tube, as the core conveying channel for biomass powder (such as compliant sawdust), has its outlet located within the receiving cavity and at a certain distance from the overall oxygen lance outlet, thus enabling thorough mixing of the biomass powder and air to ensure complete combustion.

[0017] The swirling blades surrounding the outer wall of the central tube and the inner wall of the annular sleeve assembly together form a swirling gas channel, which forces the incoming swirling gas to acquire rotational momentum before it leaves the gun body. Most importantly, the premixing channel formed at the outlet end of the central tube corresponding to the position of the annular sleeve assembly constitutes a crucial mixing chamber.

[0018] When biomass powder flows out from the central pipe outlet and encounters high-speed swirling gas ejected from the swirling gas channel, the turbulence and shear force generated by the swirling gas effectively disperse the powder clusters that are prone to form due to the "low density" of biomass. This ensures that each powder particle is enveloped by gas, achieving initial uniform mixing. This structure of "central direct powder injection, annular swirling gas, and outlet premixing" is designed directly to address the "high volatile matter" characteristic of biomass. High volatile matter means that biomass will rapidly release a large amount of combustible gas at high temperatures, requiring immediate mixing and contact with combustion-supporting gases for efficient ignition.

[0019] The premixing channel provides the necessary space and time for the thorough mixing of this gas-solid two-phase flow, solving the technical problems of unstable combustion, low flame temperature, and easy flameout caused by uneven mixing when biomass is directly injected by traditional burners, and laying a solid foundation for subsequent stable combustion.

[0020] In addition, this application also provides an electric arc furnace, including a furnace body and a plurality of the above-mentioned biomass oxygen lances, wherein the plurality of oxygen lances are obliquely installed on the furnace wall of the furnace body at an angle of 30°-45° and are evenly distributed along the circumference of the furnace body; the nozzles of the biomass oxygen lances point to the cold zone inside the furnace body.

[0021] Typically, electric arc furnaces have three distinct "cold zones" on the furnace wall, where scrap steel melts slowly, limiting overall smelting efficiency. This application addresses this by evenly arranging multiple biomass oxygen lances (e.g., 2-6 lances) around the circumference of the furnace wall at an angle of 30°-45°, allowing the high-speed, high-temperature flames from the oxygen lances to directly and precisely impact the scrap steel in these cold zones.

[0022] An inclination angle of 30°-45° allows the flame to cover and penetrate the scrap steel pile at the optimal angle, avoiding damage caused by the flame directly scouring the furnace lining due to an angle that is too small, and avoiding low heating efficiency due to an angle that is too large.

[0023] The circumferentially uniform arrangement ensures even heat distribution within the furnace, preventing localized overheating or underheating. In this way, the biomass oxygen lance directly and efficiently inputs chemical energy into the cold zones that require the most heat, significantly accelerating the melting rate of scrap steel, shortening smelting time, and reducing electricity consumption. Simultaneously, using biomass, a zero-carbon fuel, completely avoids the carbon emissions associated with traditional oil or natural gas burners, improving the overall environmental friendliness of the process. Attached Figure Description

[0024] To more clearly illustrate the specific embodiments of the present invention or the technical solutions in the prior art, the drawings used in the description of the specific embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are some embodiments of the present invention. For those skilled in the art, other drawings can be obtained from these drawings without creative effort.

[0025] Figure 1 A cross-sectional view of a biomass oxygen lance provided in an embodiment of the present invention; Figure 2 This is a cross-sectional view of the biomass oxygen lance provided in an embodiment of the present invention from a second perspective.

[0026] In the diagram: 1-Central tube; 101-Blunt body; 2-Swirl blade; 201-Swirl gas channel; 3-Oxygen annular sleeve; 301-Oxygen annular outlet; 4-Natural gas annular sleeve; 401-Premixed channel; 5-Natural gas annular outlet; 6-Cooling water jacket; 601-Inlet annular seam; 602-Return annular seam. Detailed Implementation

[0027] To make the objectives, technical solutions, and advantages of the embodiments of this application clearer, the technical solutions of the embodiments of this application will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of this application, and not all embodiments. The components of the embodiments of this application described and shown in the accompanying drawings can generally be arranged and designed in various different configurations. Therefore, the following detailed description of the embodiments of this application provided in the accompanying drawings is not intended to limit the scope of the claimed application, but merely represents selected embodiments of this application. All other embodiments obtained by those skilled in the art based on the embodiments of this application without inventive effort are within the scope of protection of this application.

[0028] In the description of the embodiments of this application, it should be noted that the terms "upper," "lower," "left," "right," "vertical," "horizontal," "inner," and "outer," etc., indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings, or the orientation or positional relationship commonly used when the product of the invention is in use. They are only for the convenience of describing the invention and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation. Therefore, they should not be construed as limitations on the invention. In addition, the terms "first," "second," and "third," etc., are only used to distinguish descriptions and should not be construed as indicating or implying relative importance.

[0029] Furthermore, terms such as "horizontal" and "vertical" do not imply that components must be absolutely horizontal or suspended, but rather that they can be slightly tilted. For example, "horizontal" simply means that its direction is more horizontal than "vertical," and does not mean that the structure must be completely horizontal, but can be slightly tilted.

[0030] In the description of the embodiments of this application, it should also be noted that, unless otherwise explicitly specified and limited, the terms "set," "install," "connect," and "connect" should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral connection; they can refer to a mechanical connection or an electrical connection; they can refer to a direct connection or an indirect connection through an intermediate medium; and they can refer to the internal connection of two components. Those skilled in the art can understand the specific meaning of the above terms in this invention based on the specific circumstances.

[0031] As used herein, the term “and / or” includes any one of the relevant items listed and any combination of any two or more items.

[0032] For ease of description, spatial relation terms such as “above,” “upper,” “below,” and “lower” may be used herein to describe the relationship between one element and another as shown in the accompanying drawings. Such spatial relation terms are intended to include not only the orientation depicted in the drawings but also the different orientations of the device during use or operation.

[0033] The terminology used herein is for the purpose of describing various examples only and is not intended to limit this disclosure. Unless the context clearly indicates otherwise, the singular form is also intended to include the plural form. The terms “comprising,” “including,” and “having” enumerate the stated features, quantities, operations, components, elements, and / or combinations thereof, but do not exclude the presence or addition of one or more other features, quantities, operations, components, elements, and / or combinations thereof.

[0034] Variations in the shapes shown in the accompanying drawings may occur due to manufacturing techniques and / or tolerances. Therefore, the examples described herein are not limited to the specific shapes shown in the accompanying drawings, but include changes in shape that may occur during manufacturing.

[0035] The features of the examples described herein can be combined in various ways that will be apparent upon understanding the disclosure of this application. Furthermore, although the examples described herein have various constructions, other constructions are possible, as will be apparent upon understanding the disclosure of this application. Additionally, the technical solutions of the various embodiments can be combined with each other, but only on the basis that they can be implemented by those skilled in the art. When the combination of technical solutions is contradictory or impossible to implement, it should be considered that such a combination of technical solutions does not exist and is not within the scope of protection claimed in this application.

[0036] like Figure 1 Combination Figure 2 As shown, the present invention provides a biomass oxygen lance, including a central tube 1, a swirl vane 2, and an annular slit sleeve assembly; the central tube 1, the swirl vane 2, and the annular slit sleeve assembly are coaxially sleeved from the inside to the outside, the annular slit sleeve assembly forms a receiving cavity, the central tube 1 is disposed in the receiving cavity, the swirl vane 2 surrounds the outer wall of the central tube 1, so that a swirl gas channel 201 is formed between the central tube 1 and the annular slit sleeve assembly; a premixing channel 401 is formed at the outlet end of the central tube 1 corresponding to the position of the annular slit sleeve assembly, and the swirl gas channel 201 is connected to the premixing channel 401.

[0037] Compared with existing technologies, the biomass oxygen gun provided by this invention has the following advantages: The biomass oxygen lance provided by the present invention includes a central tube 1, a swirl vane 2, and an annular slit sleeve assembly; the central tube 1, the swirl vane 2, and the annular slit sleeve assembly are coaxially sleeved from the inside to the outside, the annular slit sleeve assembly forms a receiving cavity, the central tube 1 is disposed in the receiving cavity, and the swirl vane 2 surrounds the outer wall of the central tube 1, so that a swirl gas channel 201 is formed between the central tube 1 and the annular slit sleeve assembly; a premixing channel 401 is formed at the outlet end of the central tube 1 corresponding to the position of the annular slit sleeve assembly, and the swirl gas channel 201 is connected to the premixing channel 401.

[0038] Analysis shows that the layout of the central tube 1, swirl blades 2, and annular sleeve assembly, coaxially arranged from the inside out, can ensure efficient and stable combustion of biomass fuel to a certain extent. Specifically, the central tube 1 serves as the core conveying channel for biomass powder (such as compliant sawdust), with its outlet located within the receiving cavity and at a certain distance from the overall oxygen lance outlet. This allows for thorough mixing of the biomass powder and air, ensuring complete combustion.

[0039] The swirling blades 2 surrounding the outer wall of the central tube 1 and the inner wall of the annular sleeve assembly together form a swirling gas channel 201, which forces the incoming swirling gas to acquire rotational momentum before leaving the gun body. Most importantly, the premixing channel 401 formed at the outlet end of the central tube 1 corresponding to the position of the annular sleeve assembly constitutes a key mixing chamber.

[0040] When the biomass powder flows out from the outlet of the central pipe 1 and encounters the high-speed swirling gas ejected from the swirling gas channel 201, the turbulence and shear force generated by the swirling gas effectively disperse the powder clusters that are easily formed due to the "low density" characteristics of biomass, ensuring that each powder particle is enveloped by gas and achieving initial uniform mixing. This structure of "central direct injection of powder, swirling gas in the annular slot, and premixing at the outlet" is designed directly to address the "high volatile matter" characteristic of biomass. High volatile matter means that biomass will rapidly release a large amount of combustible gas at high temperatures, requiring immediate mixing and contact with combustion-supporting gas for efficient ignition.

[0041] The premixing channel 401 provides the necessary space and time for the full mixing of this gas-solid two-phase flow, solving the technical problems of unstable combustion, low flame temperature, and easy flameout caused by uneven mixing when biomass is directly injected by traditional burners, and laying a solid foundation for subsequent stable combustion.

[0042] Optionally, such as Figure 1 Combination Figure 2 As shown, the biomass oxygen gun provided in this application also includes a cooling water jacket 6, which is disposed outside the annular sleeve assembly and is coaxially arranged with the annular sleeve assembly.

[0043] By arranging a cooling water jacket 6 coaxially outside the circumferential sleeve assembly, the durability and reliability issues of the oxygen lance in high-temperature smelting environments were resolved. When the biomass oxygen lance is in operation, its muzzle and the premixed channel 401 area are directly exposed to the high-temperature radiation and high-temperature gas recirculation inside the electric furnace. In particular, the combustion of the premixed fuel near the muzzle generates extremely high local temperatures, which can easily exceed the tolerance limits of ordinary metal materials.

[0044] Therefore, by further adding a cooling water jacket 6, the internally circulating cooling water can continuously remove a large amount of heat from the area, preventing the oxygen lance body from softening, deforming, or even melting and burning due to overheating, thereby greatly extending the service life of the oxygen lance.

[0045] By coaxially aligning the cooling water jacket 6 with the internal components, the cooling water chamber can uniformly surround the outer periphery of the high-temperature components, providing a 360° uniform cooling effect without dead angles, thus avoiding cracking of the gun body caused by thermal stress concentration due to uneven cooling.

[0046] Furthermore, a stable low-temperature lance body condition also helps maintain the stability of the internal flow field. High temperatures heat the internally flowing gases and powders, potentially causing uncontrollable factors such as gas expansion and flow rate changes. Effective cooling ensures that fuel and combustion media are injected into the furnace in the designed-intended state, indirectly guaranteeing the stability of the combustion process. Therefore, the further arrangement of the cooling water jacket 6 in this application provides crucial assurance for the long-term, stable, and safe operation of the biomass oxygen lance in the harsh electric furnace smelting environment.

[0047] Optionally, such as Figure 1 As shown, the annular sleeve assembly in this application includes an oxygen annular sleeve 3 and a natural gas annular sleeve 4; the natural gas annular sleeve 4 is sleeved outside the swirl blade 2, and the oxygen annular sleeve 3 is sleeved outside the natural gas annular sleeve 4.

[0048] By using the natural gas annular sleeve 4 fitted outside the swirl blade 2 and the oxygen annular sleeve 3 fitted outside the natural gas annular sleeve 4, a four-layer structure design of "central tube 1 - swirl gas - natural gas - oxygen" from the inside out can be formed, which reflects the combustion concept of staged and layered combustion assistance.

[0049] The innermost layer of biomass powder is premixed with the swirling gas to form a gas-solid mixture rich in volatiles. Then, the natural gas injected from the outer natural gas annular sleeve 4, as the ignition medium and auxiliary fuel, comes into contact with this mixture first.

[0050] Natural gas has the advantages of low ignition energy and fast combustion speed, which can quickly form a stable initial flame, providing a reliable high-temperature environment for igniting highly volatile biomass. The outermost oxygen annular sleeve 3 is responsible for providing the high concentration of oxygen required for the main combustion stage. This layered oxygen supply method from the outside in can form a high-temperature, oxygen-rich combustion zone around the flame, ensuring complete combustion of biomass volatiles and natural gas, releasing maximum heat.

[0051] At the same time, it avoids the safety risks such as backfire and deflagration that may be caused by prematurely mixing all the oxygen with the fuel inside the gun. This structure ingeniously solves the problem of the difficulty of direct ignition of biomass, uses natural gas to achieve stable ignition, and achieves high-temperature and efficient combustion through the supply of oxygen in the outer layer. It optimizes the flame shape, making the flame more penetrating and covering a wider range, and more effectively heating the scrap steel.

[0052] Optionally, such as Figure 1 Combination Figure 2 As shown, the inlet ends of both the oxygen annular sleeve 3 and the natural gas annular sleeve 4 in this application are annular, and the outlet ends of both the oxygen annular sleeve 3 and the natural gas annular sleeve 4 are gas outlets, which are evenly distributed circumferentially.

[0053] By changing the outlets of the oxygen annular sleeve 3 and the natural gas annular sleeve 4 from continuous annular gaps to discrete, circumferentially uniformly distributed outlet holes, i.e., annular hole structure, the gas outlet velocity and jet flow rate can be significantly improved.

[0054] According to fluid mechanics principles, at the same flow rate, reducing the outlet cross-sectional area can multiply the outlet velocity of the fluid. Therefore, by transforming the wide annular slit into multiple small-diameter oxygen annular slit outlets 301 and natural gas annular slit outlets 5, natural gas and oxygen can be ejected at extremely high speeds.

[0055] High-speed jets have stronger entrainment and penetration capabilities. On the one hand, they can more effectively draw in surrounding furnace gases and promote mixing with fuel. On the other hand, high-speed airflow can resist pressure fluctuations that may exist in the furnace, ensuring the rigidity and stability of the flame and preventing the flame from becoming weak or being blown away by the airflow in the furnace.

[0056] The circumferentially evenly distributed vent holes ensure that the gas supply is uniform and symmetrical from any circumferential angle. This is crucial for forming a stable, axisymmetric flame shape and avoids adverse phenomena such as flame deflection and localized high temperatures caused by uneven gas distribution. This achieves controllable, concentrated, and high-speed flame control.

[0057] Optionally, in this application, the outlet direction of the gas outlet of the natural gas annular sleeve 4 forms an angle of 45°-70° with the axis of the central pipe 1, and the outlet direction of the gas outlet of the oxygen annular sleeve 3 forms an angle of 0°-30° with the axis of the central pipe 1. Furthermore, the gas outlets of the natural gas annular sleeve 4 and the oxygen annular sleeve 3 are staggered in the axial direction of the central pipe 1.

[0058] The outlet direction of the natural gas annular sleeve 4 is set at an angle of 45°-70° with the axis of the central pipe 1. The purpose is to form a centripetal converging rotating gas flow. This obliquely injected natural gas flow forms an effective gas envelopment zone in front of the oxygen lance outlet. It can wrap the biomass mixed gas flow from the premixed channel 401 in the center, forming a favorable "gas-coated powder" structure.

[0059] This not only enhances the mixing of natural gas and biomass volatiles, but more importantly, this combustion layer acts as a barrier, slowing the diffusion rate of the central biomass powder stream and extending its residence time in the high-temperature zone, ensuring complete combustion. Simultaneously, this large-angle oblique injection helps create a strong internal recirculation zone near the nozzle, drawing downstream high-temperature flue gas back to the fire root, continuously providing heat for ignition and stabilizing the flame.

[0060] Setting the outlet direction of the oxygen annular sleeve 3 at a small angle of 0°-30° with the axis is to provide a relatively parallel, concentrated, high-speed oxygen jet. This oxygen flow mainly acts on the periphery and rear middle part of the flame, providing sufficient combustion-supporting gas for the fully diffused fuel, ensuring complete combustion, and giving the flame sufficient length and penetration to reach the scrap steel further away. Axially staggering the outlets of the two gases prevents oxygen and natural gas from mixing too early and too quickly at the muzzle, achieving staged and segmented control of the combustion process. Natural gas first ignites and stabilizes the biomass flame, and then the outer layer of oxygen completes the main combustion. This greatly optimizes the combustion process, improves efficiency, and reduces the generation of pollutants such as nitrogen oxides.

[0061] Optionally, the width of the swirl blade 2 in this application is the same as the gap distance of the swirl gas channel 201, and multiple swirl blades 2 are evenly distributed on the outer wall of the central tube 1 along the circumference of the central tube 1. The outlet direction of the swirl blade 2 forms an angle of 30°-45° with the axis.

[0062] The width of the swirl blade 2 is the same as the gap distance of the swirl gas channel 201. This design ensures that the swirl blade 2 can completely fill the annular space in which it is located, and guides all the swirling gas passing through to form a rotating flow in the direction of the blade's flow. This avoids short-circuiting of the gas on the side of the blade or the generation of irregular vortices, and ensures the efficiency and consistency of the swirl effect.

[0063] Multiple blades are evenly distributed around the central tube 1 to generate a balanced and symmetrical swirling flow field, which is a prerequisite for forming a stable, axisymmetric flame. Limiting the exit angle of the swirling blades 2 to 30°-45° can, to some extent, prevent the airflow from being too weak, which would result in insufficient rotational intensity and insufficient centrifugal force, hindering the mixing of powder and gas and the formation of the subsequent recirculation zone. On the other hand, if the angle is too large, the airflow resistance will increase significantly, resulting in large energy loss and an excessively small axial velocity component, leading to an overly short and thick flame, or even backfire. This ensures that the biomass powder is efficiently atomized, mixed, and stably combusted, providing the fundamental power source for this process.

[0064] Optionally, such as Figure 1 As shown, the outlet end of the central tube 1 in this application is provided with a blunt body 101. The blunt body 101 is connected to the edge of the outlet end of the central tube 1 through multiple support columns, and the maximum inner diameter of the blunt body 101 is greater than the inner diameter of the central tube 1. The blunt body 101 is located directly in front of the outlet end of the central tube 1.

[0065] The blunt body 101 is fixed in front of the outlet of the central tube 1 by multiple slender support columns. Its maximum inner diameter is larger than that of the central tube 1. When the biomass powder flow hits the blunt body 101, the flow direction is forced to change from the original axial flow to radial diffusion in all directions. This process greatly enhances the dispersion of powder particles and breaks the "agglomeration" phenomenon that is prone to occur due to the "low density" characteristics of powder, creating excellent conditions for subsequent mixing with air.

[0066] Furthermore, the presence of the blunt body 101 creates a stable low-speed recirculation zone downstream of it, in the direction away from the outlet of the central tube 1. The high-speed swirling gas generates a pressure difference behind the blunt body 101, drawing back the high-temperature combustion products downstream. This continuously provides the high-temperature heat source required for ignition of the newly diffused biomass powder and volatiles, forming a stable ignition source. This is crucial for maintaining flame stability and preventing flameout, especially considering the characteristic of biomass with "high volatile content" requiring timely ignition. The support column, while ensuring secure fixation, minimizes its obstruction of the flow field.

[0067] Optionally, such as Figure 1 As shown, the cooling water jacket 6 in this application includes an inlet annular seam 601 and a return annular seam 602. One end of the inlet annular seam 601 is the inlet end, and the other end is connected to one end of the return annular seam 602. The other end of the return annular seam 602 is the outlet end, and the outlet end of the return annular seam 602 and the inlet end of the inlet annular seam 601 are located at the same end of the biomass oxygen gun.

[0068] The inlet annular joint 601 is located outside the annular joint sleeve assembly, and the return annular joint 602 is located outside the inlet annular joint 601.

[0069] The inlet annular slot 601 is close to the high-temperature annular sleeve assembly, where cooling water flows in and first absorbs the heat conducted from the innermost component. Subsequently, the cooling water can enter the outer return annular slot 602, so that the cooler inlet water first contacts the hottest area, generating the maximum heat exchange temperature difference and thus obtaining the strongest cooling effect.

[0070] As the water flows from the inlet annular joint 601 to the return annular joint 602, its temperature gradually increases. Since it has already passed through the main high-temperature zone, even with the increased temperature, heat exchange with the relatively low-temperature outer shell in the return annular joint 602 effectively controls the overall temperature. Placing the inlet and outlet ends at the same end of the biomass oxygen lance greatly simplifies the connection of external water pipes, facilitates the installation, disassembly, and maintenance of the oxygen lance, and improves its convenience and reliability in placement on the electric furnace wall.

[0071] In addition, this application also provides an electric arc furnace, including a furnace body and a plurality of the above-mentioned biomass oxygen lances. The plurality of oxygen lances are installed obliquely on the furnace wall of the furnace body at an angle of 30°-45° and are evenly distributed along the circumference of the furnace body; the nozzles of the biomass oxygen lances point towards the cold zone inside the furnace body.

[0072] Typically, electric arc furnaces have three distinct "cold zones" on the furnace wall, where scrap steel melts slowly, limiting overall smelting efficiency. This application addresses this by evenly arranging multiple biomass oxygen lances (e.g., 2-6 lances) around the circumference of the furnace wall at an angle of 30°-45°, allowing the high-speed, high-temperature flames from the oxygen lances to directly and precisely impact the scrap steel in these cold zones.

[0073] An inclination angle of 30°-45° allows the flame to cover and penetrate the scrap steel pile at the optimal angle, avoiding damage caused by the flame directly scouring the furnace lining due to an angle that is too small, and avoiding low heating efficiency due to an angle that is too large.

[0074] The circumferentially uniform arrangement ensures even heat distribution within the furnace, preventing localized overheating or underheating. In this way, the biomass oxygen lance directly and efficiently inputs chemical energy into the cold zones that require the most heat, significantly accelerating the melting rate of scrap steel, shortening smelting time, and reducing electricity consumption. Simultaneously, using biomass, a zero-carbon fuel, completely avoids the carbon emissions associated with traditional oil or natural gas burners, improving the overall environmental friendliness of the process.

[0075] The above description is only a preferred embodiment of the present invention and is not intended to limit the present invention. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of the present invention should be included within the protection scope of the present invention.

Claims

1. A biomass oxygen gun, characterized in that, Includes the central tube, swirl vanes, and circumferential sleeve assembly; The central tube, the swirl vanes, and the annular sleeve assembly are coaxially sleeved from the inside to the outside. The annular sleeve assembly forms a receiving cavity, the central tube is disposed in the receiving cavity, and the swirl vanes surround the outer wall of the central tube, so that a swirling air channel is formed between the central tube and the annular sleeve assembly. A premixing channel is formed at the outlet end of the central tube corresponding to the position of the annular sleeve assembly, and the swirling gas channel is connected to the premixing channel.

2. The biomass oxygen gun according to claim 1, characterized in that, It also includes a cooling water jacket, which is disposed outside the annular sleeve assembly and is coaxially arranged with the annular sleeve assembly.

3. The biomass oxygen gun according to claim 1, characterized in that, The annular sleeve assembly includes an oxygen annular sleeve and a natural gas annular sleeve; The natural gas annular sleeve is fitted over the outside of the swirl blade, and the oxygen annular sleeve is fitted over the outside of the natural gas annular sleeve.

4. The biomass oxygen gun according to claim 3, characterized in that, The inlet ends of both the oxygen annular sleeve and the natural gas annular sleeve are annular, and the outlet ends of both the oxygen annular sleeve and the natural gas annular sleeve are gas outlets, which are evenly distributed circumferentially.

5. The biomass oxygen gun according to claim 4, characterized in that, The outlet direction of the gas outlet of the natural gas annular sleeve forms an angle of 45°-70° with the axis of the central tube, and the outlet direction of the gas outlet of the oxygen annular sleeve forms an angle of 0°-30° with the axis of the central tube. The gas outlets of the natural gas annular sleeve and the oxygen annular sleeve are staggered in the axial direction of the central tube.

6. The biomass oxygen gun according to claim 1, characterized in that, The width of the swirl blades is the same as the gap distance of the swirl air channel. Multiple swirl blades are evenly distributed along the circumference of the central tube on the outer wall of the central tube. The outlet direction of the swirl blades forms an angle of 30°-45° with the axis.

7. The biomass oxygen gun according to claim 1, characterized in that, The outlet end of the central tube is provided with a blunt body. The blunt body is connected to the edge of the outlet end of the central tube by multiple support columns, and the maximum inner diameter of the blunt body is larger than the inner diameter of the central tube. The blunt body is located directly in front of the outlet end of the central tube.

8. The biomass oxygen gun according to claim 2, characterized in that, The cooling water jacket includes an inlet annular seam and a return annular seam. One end of the inlet annular seam is the inlet end, and the other end is connected to one end of the return annular seam. The other end of the return annular seam is the outlet end, and the outlet end of the return annular seam and the inlet end of the inlet annular seam are located at the same end of the biomass oxygen gun.

9. The biomass oxygen gun according to claim 8, characterized in that, The inlet annular seam is located outside the annular seam sleeve assembly, and the return annular seam is located outside the inlet annular seam.

10. An electric arc furnace, characterized in that, The furnace body includes a furnace body and a plurality of biomass oxygen lances as described in any one of claims 1-9, wherein the plurality of oxygen lances are obliquely installed on the furnace wall of the furnace body at an angle of 30°-45° and are evenly distributed along the circumference of the furnace body; The nozzle of the biomass oxygen lance is pointed towards the cold zone inside the furnace.

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