A side wall telescopic oxygen blowing and powder injection device for electric arc furnace and a control method thereof

Abstract

This invention discloses a sidewall telescopic oxygen blowing and powder injection device for electric arc furnaces and its control method, belonging to the field of metallurgical equipment technology. It solves the technical problems of existing electric arc furnace oxygen lances being unable to adapt to changes in molten pool height and the need for the furnace door to be kept open throughout the operation of existing furnace door oxygen lances. The sidewall telescopic oxygen blowing and powder injection device of this invention includes a carbon lance, an oxygen lance, a telescopic mechanism, a support and fixing unit, and a control unit. The telescopic mechanism is fixed to the support and fixing unit; the control unit controls the telescopic mechanism's telescopic movement; both the carbon lance and oxygen lance are mounted on the telescopic mechanism, and the telescopic oxygen blowing and powder injection device can be installed on both sides of the electric arc furnace door. The carbon lance and oxygen lance extend into the furnace through holes in the water-cooled furnace wall. This sidewall telescopic oxygen blowing and powder injection device can adjust the lance head position according to the molten steel level in the furnace, and the furnace door can be closed throughout the smelting process, ensuring optimal smelting results.

Description

Technical Field

[0001] This invention relates to the field of electric arc furnace smelting technology, and in particular to a sidewall telescopic oxygen blowing powder injection device for an electric arc furnace and its control method. Background Technology

[0002] Oxygen blowing in an electric arc furnace (EAF) is an indispensable step in EAF smelting. By blowing oxygen into the molten pool, impurities affecting steel quality are oxidized, and then enriched and removed through slag formation, achieving steel purification. Simultaneously, oxygen blowing oxidizes ferrite in the molten pool to form iron oxides. Furthermore, the injection of carbon powder into the molten pool generates gas through a carbon-oxygen reaction, promoting slag foaming. This foamed slag covers the surface of the molten pool, reducing heat loss and simultaneously enveloping the electric arc to improve heat utilization, which is key to improving the smelting performance of modern EAFs. Currently, EAF oxygen supply systems mainly consist of door lances and wall lances, with some furnace types using a top-mounted oxygen lance design, but this is less common.

[0003] The structures of the furnace door lance and furnace wall lance are entirely based on the electric arc furnace structure. The furnace door lance has some movable function, while the furnace wall lance mostly adopts a fixed design. Its position is only required to meet smelting needs in the later stages of blowing. In the early stages of smelting with all-scrap electric arc furnaces, when the liquid level is low, the excessively high lance position and poor penetration can easily lead to over-oxidation of the molten steel surface, resulting in high total iron content in the slag and low steel yield. For electric arc furnaces using a high iron-to-water ratio smelting process, the poor penetration and insufficient decarburization of the molten pool affect smelting time. Furthermore, because the furnace door carbon-oxygen lance remains open throughout the smelting process, a large amount of air is drawn into the furnace, affecting the furnace atmosphere and hindering noise suppression.

[0004] Early electric arc furnaces used all-scrap steel for smelting, with scrap steel added from the top of the furnace in one or more batches via a charging basket. Due to the small furnace capacity, the density of the scrap steel was close to that of the molten iron, resulting in limited changes in the molten pool height during a single charging process. However, with the increase in electric arc furnace capacity, especially the widespread use of horizontal continuous charging electric arc furnaces, the difference between the early and later stages of the molten pool height has widened. If the oxygen blowing device uses a fixed lance position design, the distance from the nozzle to the molten surface varies more significantly with the smelting process, compromising the blowing effect. Simultaneously, the high temperature, magnetic field, and dust environment inside the furnace make it more difficult to monitor the molten pool level. Even with some adjustment capabilities in the electric arc furnace's oxygen and carbon blowing device, achieving optimal blowing results is challenging. Summary of the Invention

[0005] Based on the above analysis, the present invention aims to provide a sidewall telescopic oxygen blowing and powder injection device for electric arc furnaces and its control method, in order to solve the technical problems that existing electric arc furnace wall oxygen lances cannot adapt to changes in molten pool height and that the furnace door oxygen lances need to be used with the furnace door open throughout the process.

[0006] The objective of this invention is mainly achieved through the following technical solutions:

[0007] On one hand, the present invention provides a sidewall telescopic oxygen blowing and powder spraying device for an electric arc furnace, including a carbon lance, an oxygen lance, a telescopic mechanism, a support and fixing unit, and a control unit; the telescopic mechanism is fixed on the support and fixing unit; the control unit is used to control the telescopic mechanism to perform telescopic movements.

[0008] Both the carbon lance and the oxygen lance are mounted on the telescopic mechanism. The telescopic oxygen blowing and powder injection device is located on both sides of the furnace door of the electric arc furnace. The carbon lance and the oxygen lance extend into the furnace through holes opened in the water-cooled furnace wall of the electric arc furnace.

[0009] In one possible design, the telescopic mechanism includes a moving component, a crossarm support component, and a transmission component. The moving component is located on the top surface of the crossarm support component and is used to fix the carbon lance and oxygen lance. The moving component drives the carbon lance and oxygen lance to move on the top surface of the crossarm support component through the transmission component to change the position of the lance head inside the furnace.

[0010] In one possible design, the transmission components include a drive motor and a linear guide.

[0011] The linear guide rail is located on the top surface of the cross arm support component, and the drive motor is located on the cross arm support component. The drive motor is used to drive the moving component to move along the linear guide rail.

[0012] In one possible design, the transmission components also include a transmission chain, a first steering wheel, a second rotating wheel, and a pressure sprocket; the first steering wheel and the second steering wheel are located at both ends of the crossarm support component, and the transmission chain forms a closed loop through the first steering wheel, the second steering wheel, the drive motor, the pressure sprocket, and the moving component.

[0013] In one possible design, the crossarm support component includes the boom; the end of the boom closest to the electric arc furnace is the front end, and a fire baffle is provided on the end face of the front end of the boom.

[0014] In one possible design, the fire baffle is a flat or curved plate with a fire-resistant layer covering the fire-facing side, and a water-cooling design is used when the flames are too large.

[0015] In one possible design, an angular displacement sensor is installed on the boom to detect the tilt angle of the boom.

[0016] In one possible design, the drive motor is equipped with a drive shaft, and the drive shaft is equipped with an encoder. The encoder calculates the number of rotations of the drive motor by counting the number of pulses output by the encoder, thereby obtaining the extension and retraction length of the gun body, providing a basis for detecting the position of the gun head.

[0017] In one possible design, a tilting mechanism and a tilting mechanism drive system are also included;

[0018] The tilting mechanism is fixed to the support unit; the telescopic mechanism is connected to the support unit via the tilting mechanism, and the tilting mechanism drives the telescopic mechanism to achieve pitch movement. The tilting mechanism drive system is equipped with a position sensor and a servo mechanism, and the control unit continuously detects and compensates for the current attitude of the gun body.

[0019] On the other hand, the present invention also provides a control method for a sidewall telescopic oxygen blowing and powder injection device for an electric arc furnace, wherein the above-mentioned sidewall telescopic oxygen blowing and powder injection device for an electric arc furnace is used to control oxygen blowing and powder injection.

[0020] Compared with the prior art, the present invention can achieve at least one of the following beneficial effects:

[0021] (1) The present invention utilizes a telescopic mechanism to move the carbon lance and oxygen lance to a position away from or close to the molten steel surface, so that the lance head is always in a suitable position for smelting.

[0022] (2) The side wall telescopic oxygen blowing and powder spraying device of the present invention is set on both sides of the furnace door of the electric arc furnace. The carbon lance and oxygen lance are inserted into the furnace through the opening of the water-cooled wall of the electric arc furnace. The furnace door can be closed throughout the smelting process, thereby avoiding the large amount of air being sucked into the furnace body due to the furnace door being always open during the smelting process in the prior art, thus avoiding affecting the atmosphere inside the furnace, and also helping to suppress the noise of the electric arc furnace.

[0023] (3) The present invention enables the carbon lance and oxygen lance to maintain a certain adjustment capability through the moving parts, the cross arm support parts and the transmission parts, so as to ensure that the electric arc furnace can achieve the best blowing effect.

[0024] In this invention, the above-described technical solutions can be combined with each other to achieve more preferred combinations. Other features and advantages of this invention will be set forth in the following description, and some advantages may become apparent from the description or be learned by practicing the invention. The objects and other advantages of this invention can be realized and obtained through the embodiments described and the accompanying drawings, which are particularly pointed out. Attached Figure Description

[0025] The accompanying drawings are for illustrative purposes only and are not intended to limit the invention. Throughout the drawings, the same reference numerals denote the same parts.

[0026] Figure 1 This is a schematic diagram showing the arrangement of the sidewall telescopic oxygen blowing and powder spraying device of the present invention;

[0027] Figure 2 This is a schematic diagram of the overall structure of the sidewall telescopic oxygen blowing and powder spraying device of the present invention;

[0028] Figure 3This is a schematic diagram of the telescopic mechanism of the present invention;

[0029] Figure 4 This is a schematic diagram of the tilting mechanism of the present invention;

[0030] Figure 5 This is a schematic diagram illustrating the process of adjusting the nozzle position via the telescopic mechanism during use of the sidewall telescopic oxygen blowing and powder spraying device of the present invention.

[0031] Figure 6 This is a schematic diagram illustrating the process of adjusting the nozzle position via a tilting mechanism during use of the sidewall telescopic oxygen blowing and powder spraying device of the present invention.

[0032] Figure 7 This is a simplified schematic diagram of the sidewall telescopic oxygen blowing and powder spraying device of the present invention;

[0033] Figure 8 This is a schematic diagram of the operation of the carbon-oxygen lance of the present invention in the fixed-height sweeping mode;

[0034] Figure 9 This is a schematic diagram of the carbon-oxygen gun of the present invention operating in the positioning and lifting mode.

[0035] Figure label:

[0036] 1-Fire shield; 2-Oxygen lance; 3-Carbon lance; 4-Main boom; 41-First steering wheel; 42-Pressure sprocket; 43-Linear guide rail; 44-Drive chain; 45-Second steering wheel; 5-Drive motor; 6-Moving trolley; 7-Tilting mechanism; 71-First drive hydraulic cylinder; 72-Connecting frame; 73-Second drive hydraulic cylinder; 8-Fixed base. Detailed Implementation

[0037] The preferred embodiments of the present invention will now be described in detail with reference to the accompanying drawings, which constitute a part of the present invention and are used together with the embodiments of the present invention to illustrate the principles of the present invention, but are not intended to limit the scope of the present invention.

[0038] On one hand, the present invention provides a sidewall telescopic oxygen blowing and powder injection device for an electric arc furnace, such as... Figure 2 As shown, the device includes a carbon lance 3, an oxygen lance 2, a tilting mechanism 7, a telescopic mechanism, a support and fixing unit, and a control unit. The telescopic mechanism is fixed to the support and fixing unit via the tilting mechanism 7, and the control unit is used to control the telescopic mechanism to perform telescopic movements. Both the carbon lance 3 and the oxygen lance 2 are mounted on the telescopic mechanism. The telescopic oxygen blowing and powder spraying device is located on both sides of the furnace door of the electric arc furnace. The carbon lance 3 and the oxygen lance 2 extend into the electric arc furnace through holes in the water-cooled furnace wall.

[0039] Specifically, the carbon lance 3 and oxygen lance 2 are arranged in parallel, with one end fixed to the telescopic mechanism and the other end extending into the interior of the electric arc furnace through a hole in the water-cooled wall. The lance heads face the molten steel surface inside the electric arc furnace. In the early stage of all-scrap electric arc furnace smelting, the molten steel level in the molten pool is low, while it increases during smelting. At this time, it is necessary to adjust the lance head positions of the carbon lance 3 and oxygen lance 2. This invention uses a moving component to move the carbon lance 3 and oxygen lance 2 (referred to as carbon-oxygen lances) on the top surface of the crossarm support component, so that the lance positions of the carbon-oxygen lances located at the furnace door can be telescopic.

[0040] Compared with the prior art, the present invention uses a telescopic mechanism to move the carbon lance 3 and the oxygen lance 2 to a position away from or close to the molten steel surface, so that the lance head is always in a suitable position for smelting.

[0041] Existing furnace wall oxygen lances 2 use fixed positions, making it impossible to adjust the lance head position inside the furnace. Furthermore, existing furnace door oxygen lances 2 require opening the furnace door during smelting. Compared to existing technologies, the side-wall telescopic oxygen blowing and powder injection device of this invention is installed on both sides of the electric arc furnace door (e.g., Figure 1 As shown, the carbon lance 3 and oxygen lance 2 extend into the furnace through openings in the water-cooled wall of the electric arc furnace, meaning that the carbon lance 3 and oxygen lance 2 do not enter the furnace through the furnace door. Therefore, the furnace door can be closed throughout the smelting process, which avoids the large amount of air being drawn into the furnace body due to the furnace door being constantly open during the smelting process, as is the case in the prior art. This avoids affecting the atmosphere inside the furnace and also helps to suppress the noise of the electric arc furnace.

[0042] It should be explained that the support and fixing unit of the present invention includes a fixing base, which is installed on the platform and is used to provide stable support for other mechanisms.

[0043] like Figure 3 As shown, the telescopic mechanism of the present invention includes a moving component, a crossarm support component, and a transmission component. The moving component is disposed on the top surface of the crossarm support component and is used to fix the carbon lance 3 and the oxygen lance 2. The moving component drives the carbon lance 3 and the oxygen lance 2 to move on the top surface of the crossarm support component through the transmission component.

[0044] Specifically, in this invention, the carbon lance 3 and oxygen lance 2 are arranged in parallel, with their ends furthest from the electric arc furnace fixed to a moving component. The moving component is located on the top surface of the crossarm support. A transmission component is connected to the moving component, which in turn moves the moving component, thereby moving the carbon lance 3 and oxygen lance 2 on the top surface of the crossarm support. This changes the lance head positions of the carbon lance 3 and oxygen lance 2 within the electric arc furnace, allowing the lance head positions to be adjusted according to changes in the molten steel level. That is, when the molten steel level in the furnace rises, the transmission component moves the moving component away from the molten steel level, thereby raising the lance head position; when the molten steel level in the furnace decreases, the transmission component moves the moving component closer to the molten steel level, thereby lowering the lance head position.

[0045] Compared with the prior art, the present invention enables the carbon lance 3 and oxygen lance 2 to maintain a certain degree of adjustability through moving parts, cross arm support parts and transmission parts, so as to ensure that the electric arc furnace can achieve the best blowing effect.

[0046] like Figure 3 As shown, the transmission component of the present invention includes a drive motor 5 and a linear guide rail 43; the linear guide rail 43 is disposed on the top surface of the cross arm support component, and the drive motor 5 is disposed on the cross arm support component. The drive motor 5 is used to drive the moving component to move along the linear guide rail 43.

[0047] like Figure 3 As shown, the transmission component of the present invention further includes a transmission chain 44, a first steering wheel, a second rotating wheel, and a pressure sprocket 42; the first steering wheel and the second steering wheel are located at both ends of the cross arm support component, and the transmission chain 44 forms a closed loop through the first steering wheel 41, the second steering wheel 45, the drive motor 5, the pressure sprocket 42, and the moving component.

[0048] Specifically, the first steering wheel and the second steering wheel are respectively located at the two ends of the cross arm support component. The transmission chain 44 is located on the first steering wheel and the second steering wheel. The clamping sprocket 42 is used to tightly fit the transmission chain 44 to ensure the stability and tightness of the transmission chain 44 and prevent the transmission chain 44 from falling off due to loosening. The drive motor 5 is used to provide power so that the moving component drives the oxygen lance 2 and the carbon lance 3 to slide along the linear guide rail 43 at the top of the cross arm support component to change the position of the lance head in the furnace and adjust it according to the change of the molten steel level.

[0049] Compared with the prior art, the telescopic unit of the present invention has a simple structure, long stroke, is easy to maintain, and has a relatively low cost; in addition, the longer its stroke, the more obvious its cost advantage.

[0050] It should be noted that the moving part of the present invention is a moving trolley 6. The carbon lance 3 and the oxygen lance 2 are both fixed on the moving trolley 6. The moving trolley 6 can slide along the linear guide rail 43 on the top surface of the upper arm 4, and its power is provided by the drive motor 5.

[0051] Compared with existing technologies, the mobile trolley 6 of this invention has a simple structure, low cost, and is easy to maintain.

[0052] To prevent hot fumes and flames from affecting the device during the blowing process, the horizontal arm support component of the present invention includes a main arm 4; the end of the main arm 4 closest to the electric arc furnace is the front end, and a fire baffle 1 is provided on the end face of the front end of the main arm 4; the fire baffle 1 is a vertical flat plate or a vertically placed arc plate.

[0053] Specifically, the fire baffle 1 is made of welded steel plates, and the fire-facing surface is covered with fire-resistant material. This invention blocks flames or hot smoke by setting the fire baffle 1, thus avoiding adverse effects on the equipment.

[0054] The boom 4 of this invention is equipped with an angular displacement sensor, which is used to detect the current tilt angle of the boom 4. In addition, a drive shaft is provided on the drive motor 5, and an encoder is provided on the drive shaft. The encoder calculates the number of rotations of the drive motor 5 by counting the number of pulses output by the encoder, thereby determining the extension length and providing a basis for the position of the detection gun head.

[0055] To achieve the pitching of the sidewall telescopic oxygen blowing powder injection device, the sidewall telescopic oxygen blowing powder injection device for electric arc furnace of the present invention further includes a tilting mechanism 7, which is fixed on the support fixing unit (i.e., the fixed base); the telescopic mechanism is connected to the support fixing unit through the tilting mechanism 7; the tilting mechanism 7 is used to drive the telescopic mechanism to pitch.

[0056] Most existing furnace wall lances adopt a fixed lance position design. In the early stage of smelting of all-scrap electric arc furnaces, when the liquid level is low, the lance position is too high and the penetration ability is poor, which can easily cause the surface of the molten steel in the pool to be over-oxidized, resulting in high total iron content in the steel slag and low steel yield. For electric arc furnaces using high iron-to-water ratio smelting process, the poor penetration ability and insufficient decarburization ability of the molten pool affect the smelting time.

[0057] Compared with the prior art, the present invention sets up a tilting mechanism 7, which drives the boom 4 to tilt at a certain angle, so that the positions of the carbon lance 3 and oxygen lance 2 can be adjusted according to the changes in the molten steel level in the furnace, so as to achieve the best blowing effect.

[0058] like Figure 4As shown, the tilting mechanism 7 of the present invention includes a first driving hydraulic cylinder 71, a second driving hydraulic cylinder 73, and a connecting frame 72; the bottom of the end of the boom 4 near the electric arc furnace is provided with a first hinge point and a second hinge point, and the support fixing unit is provided with a third hinge point and a fourth hinge point; one end of the boom 4 is hinged to the first driving hydraulic cylinder 71 at the first hinge point, and one end of the connecting frame 72 is hinged to the second hinge point; the other end of the first driving hydraulic cylinder 71 is hinged to the support fixing unit at the third hinge point; the other end of the connecting frame 72 is hinged to the support fixing unit at the third hinge point; one end of the second driving hydraulic cylinder 73 is hinged to the boom 4 at the second hinge point, and the other end is hinged to the support fixing unit at the fourth hinge point.

[0059] Specifically, as shown in the figure, the tilting mechanism 7 of the present invention adopts a dual-drive, dual-rotating-shaft design. One end of the boom 4 is hinged to the first drive hydraulic cylinder 71 at a first hinge point (denoted as hinge point A), and to one end of the connecting frame 72 at a second hinge point (denoted as hinge point B). The other end of the first drive hydraulic cylinder 71 is hinged to the support and fixing unit at a third hinge point (denoted as hinge point C). The other end of the connecting frame 72 is hinged to the support and fixing unit at the third hinge point. One end of the second drive hydraulic cylinder 73 is hinged to the boom 4 at the second hinge point, and to the support and fixing unit at the third hinge point. The unit is hinged at the fourth hinge point (denoted as hinge point D). Hinge point A connects to the boom 4 and the first drive hydraulic cylinder 71; hinge point B connects to the boom 4, the second drive hydraulic cylinder 73, and the connecting frame 72; hinge point C connects to the first drive hydraulic cylinder 71, the fixed base 8, and the connecting frame 72; and hinge point D connects to the second drive hydraulic cylinder 73 and the fixed base 8. Although the four hinge points A, B, C, and D (i.e., from the first intersection point to the fourth hinge point) are connected to multiple components, each component rotates independently around its hinge point. Connecting hinge points A, B, and C forms triangle ABC, where AC represents the two ends of the first drive hydraulic cylinder 71, and AB and BC are the axes of rotation on the boom 4 and the connecting frame 72, respectively. The lengths of AB and BC are fixed. Therefore, triangle ABC can be considered a variable triangle driven by AC and rotating around the axis where hinge point B is located. The size of its ∠ABC is affected by the length of AC (i.e., the length of the first drive hydraulic cylinder 71). Similarly, hinge points B, C, and D form triangle BCD, where BD is the two ends of the second driving hydraulic cylinder 73, and BC and CD are the rotating shaft and fixed base on the connecting frame 72, respectively. The lengths of BC and CD are fixed. Therefore, triangle BCD can be regarded as a variable triangle driven by BD and rotating around the axis where hinge point C is located. The size of ∠BCD is affected by the length of BD (i.e., the length of the second driving hydraulic cylinder 73). Quadrilateral ABDC is considered to be composed of triangle ABC and triangle BCD. The included angle between AB and CD has the following relationship: Δβ=Δ∠BCD-Δ∠ABC, and the included angle β is the pitch angle of the boom 4.

[0060] In summary, the tilting mechanism 7 of the present invention adopts a dual-drive dual-rotating-shaft design. Compared with the prior art, under the same external conditions, the intersection point of the gun body rotation of the dual-drive dual-rotating-shaft structure can be controlled by the cooperation of the two rotating shafts, which makes the furnace wall opening size smaller, which is beneficial to reduce furnace body leakage and greatly helps to reduce the entry of external air into the furnace.

[0061] It should be noted that the sidewall telescopic oxygen blowing and powder injection device of the electric arc furnace of the present invention also includes a control unit, which is used to adjust the posture of carbon lance 3 and oxygen lance 2 through data transmitted by angular displacement sensor and encoder.

[0062] On the other hand, the present invention also provides a method for controlling the oxygen blowing and powder injection of a telescopic oxygen blowing and powder injection device, which uses the above-mentioned telescopic oxygen blowing and powder injection device for the side wall of an electric arc furnace, and includes the following steps:

[0063] Step 1: Determine the change in the liquid level height Δh of the molten pool by measuring the distance the electrode rises and falls;

[0064] Modern electric arc furnaces typically control the electrode system by detecting the circuit impedance. This impedance value is composed of the short-circuit system, electrodes, arc, and the current loop at the molten steel surface. When other conditions remain constant, the impedance value is determined by the distance between the electrode and the molten surface. Therefore, in electric arc furnace smelting using constant impedance control, the electrode rises with the molten pool height, and the change in the molten pool height Δh can be determined by the distance the electrode rises and falls.

[0065] After tapping steel from an electric arc furnace, a certain amount of steel remains, which is usually a fixed value. Therefore, the minimum liquid level of the electric arc furnace can be calculated using the refractory masonry diagram. Based on this position, the minimum position of the sidewall telescopic oxygen blowing device can be set. Then, the change in the molten steel level Δh can be calculated based on the lifting distance during the electrode smelting process. The lance position can be compensated according to the process requirements. The compensation value is calibrated by an encoder connected to the drive motor 5 shaft and an angular displacement sensor installed on the boom 4, which can maintain the stability of the lance position throughout the smelting process.

[0066] Step 2: Measure the current tilt angle of the gun body using an angular displacement sensor, then compare the current tilt angle of the gun body with the liquid level of the molten pool, and send the comparison result to the control unit. The control unit adjusts the attitude of the gun head according to the comparison result.

[0067] When adjusting the positions of the carbon lance 3 and oxygen lance 2 using the telescopic mechanism, the lance position is compensated by controlling the number of motor rotation pulses.

[0068] m=nΔh(πDsin(β)) -1 (1)

[0069] Where m is the number of motor rotation pulses; n is the number of pulses that the motor can output in one revolution; Δh is the range of steel molten fluctuation during the smelting process (i.e., the change in the steel molten level); D is the pitch circle diameter of the drive wheel connected to the motor; and β is the angle between the oxygen lance 2 and the horizontal plane.

[0070] Specifically, such as Figure 5 As shown in the figure, the lowest liquid level is the initial liquid level h0 at the beginning of smelting. As smelting progresses, scrap steel is continuously added through the feeding system and melted, causing the liquid level to rise continuously. The highest liquid level at the end of scrap steel feeding is h1. The fluctuation range of the molten steel during the smelting process is Δh, so Δh = h1 - h0 exists. The oxygen lance 2 has an angle β with the horizontal plane. When the liquid level rises, in order to keep the lance position h constant, the extension distance ΔL of the lance body and the liquid level height difference Δh have the following relationship: Δh = ΔLsin(β). An encoder is installed on the drive shaft of the drive motor 5. The number of pulses that the motor can output one revolution is n. The pitch circle diameter of the drive wheel connected to the motor is D. Then the distance the chain moves corresponding to a single pulse of the encoder is l = πDn. -1 During the smelting process, as the liquid level rises, the gun body needs to retreat to compensate. The compensation length is converted into the number of motor rotation pulses m. Therefore, there exists m = nΔh(πDsin(β)). -1 Therefore, in actual use, the gun position can be compensated by controlling the number of motor rotation pulses.

[0071] Using only the telescopic adjustment method will not change the jet angle, but the position of the ignition point will move to some extent, which will not have a significant impact on the smelting effect.

[0072] When the tilting mechanism 7 is used to adjust the positions of the carbon lance 3 and the oxygen lance 2, the pitch change angle Δβ of the carbon lance 3 and the oxygen lance 2 is:

[0073] Δβ=arcsin(H-h0-h)-arcsin(H-h0-h-Δh) (2)

[0074] Where Δβ is the pitch angle of the carbon-oxygen lance; H is the height of the carbon-oxygen lance's axis from the bottom of the molten pool; h0 is the initial liquid level h0 in the initial stage of smelting; and h is the lance position.

[0075] Specifically, the process of adjusting the gun position by pitching during use of the side-wall telescopic oxygen blowing and powder spraying device is as follows: Figure 6 As shown, when the pitch control gun position h is used, the distance from the gun head to the virtual axis is L, the angle between the gun body and the horizontal plane is β, and the height of the axis from the bottom of the molten pool is H. When the molten steel level rises from h0 to h1, in order to keep the gun position h unchanged, the gun body should rotate by a corresponding angle Δβ. Then the following relationship exists:

[0076] H=Lsin(β)+h0+h=Lsin(β-Δβ)+h1+h............(3)

[0077] Lsin(β)+h0=Lsin(β-Δβ)+h1............(4)

[0078] (sin(β)-sin(β-Δβ))=Δh·L -1 ......................(5)

[0079] In the formula, the angle β between the gun body and the horizontal plane can be obtained by the angular displacement sensor, and the gun body extension length L can be calculated by the number of encoder rotation pulses on the drive motor 5. The angle Δβ that the gun body needs to compensate for when the gun position changes Δh can be obtained by formula (5).

[0080] To simplify the calculation, a coordinate system is established with the virtual pivot point of the gun body as the zero point, the horizontal direction as the X-axis, and the vertical direction as the Y-axis. Furthermore, the extension length L0 = 1m, and the elevation angle change Δβ is:

[0081] Δβ=arcsin(H-h0-h)-arcsin(H-h0-h-Δh)......(6)

[0082] H and h0 are determined during the design phase. h is the gun position height, which is determined according to the smelting process. Δh is the rising height of the molten pool, which can be determined by raising and lowering the electrodes. Δβ is the pitch change angle, and its value is related to the height change.

[0083] Since the corresponding data formula is calculated based on a penetration length L0 = 1m, in actual use, the height change Δh needs to be corrected according to the actual penetration length. Then, the corresponding Δβ in the array is retrieved using the corrected Δh and β values ​​and submitted to the control unit for gun attitude control. While using pitch control to adjust the gun position height will affect the incident angle of the jet, which will have a certain impact on smelting, adjusting the pitch angle can significantly change the jet injection position, so it can be used in conjunction with telescopic control.

[0084] It should be noted that the pitching and telescopic processes of the sidewall telescopic oxygen blowing powder spraying device of the present invention are two independent processes, both of which can achieve control of the gun position; the difference is that while the pitching changes the gun position, it also changes the jet angle, and the intersection point of the oxygen jet and the molten pool moves accordingly; the jet angle does not change during telescopic movement, and the position of the ignition point moves back and forth with the telescopic movement, but the range is small; these two actions can be performed simultaneously or separately.

[0085] Existing technologies often employ fixed-position oxygen blowing, which leads to problems such as the lance position being too high in the early stages, resulting in poor oxygen blowing and slag formation, and the lance position being too low in the later stages, making it prone to lance burnout. Compared with existing technologies, the side-wall telescopic oxygen blowing and powder spraying device of this invention can automatically extend and retract to control the lance position, thereby avoiding the problems caused by fixed-position oxygen blowing. The side-wall telescopic oxygen blowing and powder spraying device and its control method of this invention can maintain the oxygen blowing effect at its optimal state throughout the entire smelting cycle.

[0086] Example 1

[0087] like Figure 7 As shown, the present invention simplifies the sidewall telescopic oxygen blowing and powder spraying device. The gun body control consists of three driving parts: tilting 1, tilting 2 and telescopic; wherein, the tilting 1 angle is a1, the tilting 2 angle is a2, the telescopic displacement is S, the current gun position height is h, and the gun body angle is β.

[0088] The basic action modes of the gun can be divided into fixed-height sweeping and fixed-position lifting. The remaining actions can be regarded as combinations of these two basic modes.

[0089] like Figure 8 As shown, when using the side-wall telescopic oxygen blowing powder spraying device of the present invention to perform fixed-height sweeping, by changing the values ​​of a1, a2 and S, when the speeds of the three are appropriate, the gun body can be moved back and forth without changing the gun position h, which can be used to expand the oxygen supply area.

[0090] like Figure 9 As shown, when using the side-wall telescopic oxygen blowing powder spraying device of the present invention for positioning and lifting the gun, by changing the values ​​of a1, a2 and S, when the speeds of the three are appropriate, the gun position can be changed up and down without changing the position of the gun head, thereby adjusting the gun position and improving the impact and stirring of oxygen on the molten pool.

[0091] It should be noted that the parameter matching for the two action modes, namely, fixed height sweeping and fixed position lifting, is calculated and fixed in the corresponding model of the control unit. In actual use, different trajectories and gun positions are achieved by recalling and combining these parameters.

[0092] The above description is only a preferred embodiment of the present invention, but the scope of protection of the present invention is not limited thereto. Any changes or substitutions that can be easily conceived by those skilled in the art within the scope of the technology disclosed in the present invention should be included within the scope of protection of the present invention.

Claims

1. A sidewall telescopic oxygen blowing and powder injection device for an electric arc furnace, characterized in that, It includes a carbon lance, an oxygen lance, a telescopic mechanism, a support and fixing unit, and a control unit; the telescopic mechanism is fixed to the support and fixing unit; the control unit is used to control the telescopic mechanism to perform telescopic movements. The carbon lance and oxygen lance are both mounted on the telescopic mechanism. The telescopic oxygen blowing and powder spraying device is located on both sides of the furnace door of the electric arc furnace. The carbon lance and oxygen lance extend into the furnace through openings in the water-cooled furnace wall of the electric arc furnace. The telescopic mechanism includes a moving component, a crossarm support component, and a transmission component. The moving component is located on the top surface of the crossarm support component and is used to fix the carbon lance and the oxygen lance. The moving component drives the carbon lance and the oxygen lance to move on the top surface of the crossarm support component through the transmission component to change the position of the lance head inside the furnace. The transmission components include a drive motor and a linear guide rail; The linear guide rail is disposed on the top surface of the cross arm support component, and the drive motor is disposed on the cross arm support component. The drive motor is used to drive the moving component to move along the linear guide rail. The transmission component further includes a transmission chain, a first steering wheel, a second steering wheel, and a pressure sprocket; the first steering wheel and the second steering wheel are located at both ends of the crossarm support component, and the transmission chain forms a closed loop through the first steering wheel, the second steering wheel, the drive motor, the pressure sprocket, and the moving component; The crossarm support component includes a main arm; the end of the main arm closest to the electric arc furnace is the front end, and a fire baffle is provided on the end face of the front end of the main arm; An angular displacement sensor is installed on the boom, and the angular displacement sensor is used to detect the tilt angle of the boom; The drive motor is equipped with a drive shaft, and the drive shaft is equipped with an encoder. The encoder calculates the number of rotations of the drive motor by counting the number of pulses output by the encoder, thereby obtaining the extension and retraction length of the gun body, providing a basis for detecting the position of the gun head. It also includes a tilting mechanism and a tilting mechanism drive system; The tilting mechanism is fixed to the support fixing unit; the telescopic mechanism is connected to the support fixing unit through the tilting mechanism, and the tilting mechanism is used to drive the telescopic mechanism to achieve pitching action; the tilting mechanism drive system is equipped with a position sensor and a servo mechanism, and the control unit detects and compensates for the current attitude of the gun body at any time.

2. The sidewall telescopic oxygen blowing and powder spraying device for an electric arc furnace according to claim 1, characterized in that, The fire baffle is a flat plate or an arc plate.

3. A control method for a sidewall telescopic oxygen blowing and powder injection device for an electric arc furnace, characterized in that, The oxygen blowing and powder injection device for the side wall telescopic oxygen blowing of the electric arc furnace as described in claim 1 or 2 is used for control of oxygen blowing and powder injection.

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