Low-carbon-emission steelmaking method and low-carbon-emission steelmaking system

Abstract

The invention provides a low-carbon-emission steelmaking method and a low-carbon-emission steelmaking system, and relates to the field of metallurgy. The low-carbon-emission steelmaking method comprises the steps that biochar is injected into steel slag through a spray gun, and it is guaranteed that an outlet of the spray gun is located 300-600 mm above an interface of molten steel and the steel slag all the time and located in the steel slag through a telescopic system; when the temperature of the gun body of the spray gun is larger than or equal to the control temperature, the telescopic system controls the spray gun to execute retraction action, and after staying for a preset time, if the temperature of the gun body of the spray gun falls below the control temperature, the position of the spray gun is kept unchanged, and if the temperature of the gun body of the spray gun does not fall below the control temperature, the position of the spray gun is not changed. And if not, continuing to retract until the temperature of the gun body of the spray gun is lower than the control temperature. According to the low-carbon-emission steelmaking method and the low-carbon-emission steelmaking system, the stable foaming slag state is always kept in the smelting process, the smelting power consumption can be remarkably reduced, and the smelting efficiency can be improved.

Description

Technical Field

[0001] The present application relates to the field of metallurgy, and in particular to a low-carbon emission steelmaking method and a low-carbon emission steelmaking system. Background Art

[0002] Biochar, as a unique "zero-carbon" renewable carbon source, has become an ideal alternative to traditional foaming agent carbon sources in the field of electric furnace steelmaking. Compared with other fossil fuel foaming agents such as anthracite, coke powder and lignite, biochar has the characteristics of low density and high reactivity. This high reactivity promotes the rapid reduction reaction between biochar and slag, effectively generating a large amount of CO gas, thereby achieving slag foaming.

[0003] However, the traditional arc furnace injection method has limitations. The biochar still has a distance to reach the slag surface after the spray gun outlet. Its low density leads to insufficient impact force of the powder. Some powder is sucked away by the dust removal system before it touches the slag surface, and the powder that reaches the slag surface is difficult to penetrate into the slag layer, resulting in a large amount of waste of biochar powder and a significant decrease in utilization efficiency. At the same time, the reducing gas generated by the reaction of biochar powder and slag is difficult to remain in the slag layer, affecting the foaming effect of the slag.

[0004] Therefore, there is an urgent need to develop a blowing technology suitable for the low density and high reactivity characteristics of biochar, so as to adapt to the low density and high reactivity characteristics of biochar and accelerate its widespread application in the field of electric furnace steelmaking. Summary of the invention

[0005] The purpose of this application is to provide a low-carbon emission steelmaking method and a low-carbon emission steelmaking system to solve the above problems.

[0006] To achieve the above objectives, this application adopts the following technical solutions: A low-carbon emission steelmaking method comprising: The biochar is sprayed into the slag using a spray gun, wherein the spray gun is ensured by a telescopic system that its outlet is always located 300-600 mm above the interface between the molten steel and the slag and is located within the slag; The telescopic system controls the movement distance of the spray gun to satisfy the following formula 1: ; in, is the distance the spray gun should be retracted when When it is 0, the sliding distance of the spray gun in the current gear can be obtained. ; The height of the spray gun muzzle from the bottom of the molten pool when the spray gun is in the initial position (obtained by initial setting, measurement or calculation based on equipment size, position and other data); The real-time height of the steel liquid level; The vertical distance between the outlet of the spray gun and the steel liquid surface; θ is the installation angle of the spray gun. The angle of the spray gun at the furnace wall and furnace door is defined as the angle between the tail of the spray gun and the direction of the gun head and the horizontal line. The angle of the spray gun at the furnace top is 90 degrees. is the distance the spray gun has moved; When the gun body temperature of the spray gun is greater than or equal to the control temperature, the telescopic system controls the spray gun to perform a retraction action, and then after staying for a preset time, if the gun body temperature of the spray gun drops below the control temperature, the position of the spray gun is kept unchanged; if the gun body temperature of the spray gun does not drop below the control temperature, it continues to retract until the gun body temperature of the spray gun is lower than the control temperature.

[0007] It should be noted that, first of all, compared with the spray gun muzzle being located above the slag, the present application limits the spray gun muzzle to be located 300-600mm above the interface between the molten steel and the slag and inside the slag, thereby effectively solving the problem of low utilization efficiency of traditional biochar injection and greatly reducing the amount of biochar injection; in addition, the smelting process always maintains a stable foam slag state, which can significantly reduce smelting power consumption and improve smelting efficiency. Secondly, the height of the molten steel level changes in real time during the smelting process. Therefore, to ensure that the spray gun muzzle is always located 300-600mm above the interface between the molten steel and the slag and inside the slag, it is necessary to dynamically adjust the position of the spray gun. Therefore, the actual distance that the spray gun needs to move is calculated by the above formula, and then the real-time adjustment is completed by the telescopic system; finally, the spray gun itself is equipped with a cooling water circulation. If the temperature of the gun body is not controlled, the gun body will be damaged. On the one hand, the cooling water enters the molten steel, causing safety problems. On the other hand, the spray gun will need to be frequently replaced, increasing production costs. Therefore, it is necessary to retract the spray gun to keep it away from the molten steel, reduce the temperature, and ensure safety.

[0008] Preferably, the Obtained by: A 3D full-size geometric model of the arc furnace molten pool was established. By adjusting the molten steel level in the geometric model, the volume of molten steel corresponding to different molten steel heights was calculated. The molten steel level height was adjusted in increments of 10 mm to 50 mm. The calculated molten steel volume data is subjected to data fitting analysis to determine the molten steel level height. Mathematical relationship model between the volume of molten steel and the By expressing the volume of molten steel as the ratio of its weight to its density, the height of the molten steel level can be derived. A quantitative relationship between the density of molten steel and the weight of molten steel; the weight of molten steel is calculated based on the amount of iron-containing raw materials added to the electric arc furnace.

[0009] During the smelting process, according to the amount of iron-containing raw materials added and the set steel liquid density value, the quantitative relationship is used to calculate the .

[0010] Preferably, the quantitative relationship needs to be calibrated regularly within 200-300 smelting cycles.

[0011] Preferably, the gun body temperature of the spray gun is measured by a temperature sensor; The temperature sensor is installed between the biochar powder spray pipe and the water cooling jacket of the spray gun; The maximum measurement temperature of the temperature sensor is not less than 1300°C, and the measurement accuracy is ±3°C.

[0012] Preferably, the telescopic system controls the movement distance of the spray gun along its movement direction to be 3-5 meters; The moving distance is measured by a displacement sensor.

[0013] Preferably, the retraction action includes at least 3 gears, corresponding to They are 400mm, 500mm and 600mm respectively.

[0014] For ease of implementation, in a preferred embodiment, the initial The position is set to 300mm, and then retracted to 400mm, 500mm, and 600mm positions according to the measured temperature.

[0015] Preferably, the installation position of the spray gun includes any one of the outer side of the electric furnace wall, the electric furnace door and the electric furnace top; The initial position of the spray gun arranged on the outer side of the electric furnace wall is that the muzzle is 150-300mm away from the furnace wall surface; the initial position of the spray gun arranged on the electric furnace door is that the muzzle is 500-1000mm away from the outside of the furnace door; the initial position of the spray gun arranged on the electric furnace top is that the muzzle is 300-800mm away from the outer side of the furnace cover.

[0016] Preferably, the controlled temperature is not higher than 800°C.

[0017] Preferably, the spraying amount of the biochar sprayed by the spray gun is 15-25kg / ton of steel.

[0018] The present application also provides a low-carbon emission steelmaking system for executing the low-carbon emission steelmaking method; The low-carbon emission steelmaking system includes an electric furnace, a spray gun, a telescopic mechanism and a control system. The spray gun is arranged at any position of the outer side of the electric furnace wall, the electric furnace door and the electric furnace top. The spray gun is connected to the mobile module in the telescopic mechanism. The control system is used to receive data, process data and control the mobile module according to the data processing results, thereby controlling the spray gun to move away from or approach the interface between molten steel and slag in the electric furnace.

[0019] Compared with the prior art, the beneficial effects of this application include: Compared with the traditional steelmaking biochar injection technology, the low-carbon emission steelmaking method and low-carbon emission steelmaking system provided by the present application can realize the dynamic regulation of the biochar injection position during the entire steelmaking process to ensure that the biochar leaves the muzzle and directly enters the deep slag layer, significantly improving the utilization efficiency of the biochar and reducing the amount of biochar injection. In addition, the high volatility and high reactivity of biochar are fully utilized to effectively promote the rapid and stable formation of foamed slag, thereby significantly reducing the power consumption during the smelting process and shortening the overall smelting cycle.

[0020] The low-carbon emission steelmaking method and low-carbon emission steelmaking system provided in the present application can be used for steelmaking processes of all different charge structures such as 50-200t of all scrap steel, scrap steel + molten iron, scrap steel + direct reduced iron, etc. The use of this method can reduce the amount of biochar injection by 1-5kg / ton of steel, shorten the electric furnace smelting time by 3-6min, and reduce the energy consumption by 4-12kWh / ton of steel compared with traditional biochar injection technology. BRIEF DESCRIPTION OF THE DRAWINGS

[0021] In order to more clearly illustrate the technical solutions of the embodiments of the present application, the drawings required for use in the embodiments will be briefly introduced below. It should be understood that the following drawings only show certain embodiments of the present application and therefore should not be regarded as limiting the scope of the present application.

[0022] Figure 1 A schematic diagram of a low carbon emission steelmaking system used in an embodiment of the present application; Figure 2 Schematic diagram of the control principle of the low-carbon emission steelmaking system provided for this application.

[0023] Reference numerals: 1- spray gun; 2- telescopic mechanism; 3- electric arc furnace; 4- control system. DETAILED DESCRIPTION

[0024] The embodiments of the present application will be described in detail below in conjunction with specific examples, but it will be appreciated by those skilled in the art that the following examples are only used to illustrate the present application and should not be considered as limiting the scope of the present application. If specific conditions are not specified in the examples, they are carried out according to normal conditions or the conditions recommended by the manufacturer. If the manufacturer is not specified in the reagents or instruments used, they are all conventional products that can be purchased commercially.

[0025] First, the low-carbon emission steelmaking system used in the embodiment of the present application is described as follows: like Figure 1 As shown, the low-carbon emission steelmaking system is a control system for submerged injection of biochar in an electric furnace steelmaking process, specifically comprising: a spray gun 1, a telescopic mechanism 2, an electric arc furnace 3 and a control system 4.

[0026] Among them, the spray gun 1 is arranged on the telescopic mechanism 2, and the muzzle of the spray gun 1 is arranged above the interface between the molten steel and the slag (slag layer) in the electric arc furnace 3 and is located in the slag, and under the control of the control system 4, the telescopic mechanism 2 can realize the up and down movement of the gun body to ensure that the muzzle of the spray gun 1 is always located 300-600mm above the interface between the molten steel and the slag (slag layer) and is located in the slag.

[0027] The gun body temperature of the spray gun 1 is measured by a temperature sensor; the temperature sensor is installed between the biochar powder spray pipe and the water cooling sleeve of the spray gun; the maximum measurement temperature of the temperature sensor is not less than 1300°C, and the measurement accuracy is ±3°C.

[0028] The telescopic mechanism 2 is provided with a displacement sensor (distance sensor) for measuring the moving distance of the spray gun 1 .

[0029] In an optional embodiment, the installation position of the spray gun includes any one of the outside of the electric furnace wall, the electric furnace door and the electric furnace roof; the initial position of the spray gun arranged on the outside of the electric furnace wall is that the muzzle is 150-300mm away from the furnace wall surface; the initial position of the spray gun arranged on the electric furnace door is that the muzzle is 500-1000mm away from the outside of the furnace door; the initial position of the spray gun arranged on the electric furnace roof is that the muzzle is 300-800mm away from the outside of the furnace cover.

[0030] In order to facilitate control, the retraction of the spray gun 1 is set to 4 gears, including the initial gear and 3 retraction gears ABC. is 300mm, then position A 400mm, B position 500mm, C position It is 600mm.

[0031] Figure 2 The control principle of the above system is demonstrated.

[0032] Example 1 This embodiment provides a 120t electric arc furnace scrap steel + 30% molten iron smelting process, and the injected biochar is corn straw biochar. The biochar has a fixed carbon content of 75%, an ash content of 13%, a moisture content of 2%, and a particle size of 2mm.

[0033] The biochar spray gun is installed on the furnace wall. The initial position is 200 mm from the gun muzzle to the furnace wall. The installation angle is 30°. When the spray gun is in the initial position, the height of the gun muzzle from the bottom of the furnace molten pool is It is 2100mm.

[0034] During the smelting process Obtained by: 1. Use SolidWorks software to build a 3D full-size geometric model of the arc furnace molten pool. Use the volume calculation function of the software to adjust the steel liquid level in the geometric model to calculate the volume of the steel liquid corresponding to different steel liquid heights. The steel liquid level changes in 30mm increments. 2. Import the molten steel volume data calculated in SolidWorks software into Matlab or Python software for data fitting analysis to determine the molten steel level height Furthermore, by expressing the volume of molten steel as the ratio of the weight of molten steel to its density, the height of the molten steel level is derived. The quantitative relationship between the density of molten steel and the weight of molten steel. The density of molten steel is set to 7.2g / cm³. If the amount of scrap steel added is 60t and the amount of molten iron added is 36t, the weight of molten steel is 96t.

[0035] 3. During the smelting process, the control system calculates the above-mentioned quantitative relationship in real time according to the amount of scrap steel and molten iron added and the set steel liquid density value. .

[0036] Furnace geometry, steel level The mathematical relationship between the density and weight of the molten steel is calibrated regularly once every 240 smelting cycles. The maximum measuring temperature of the temperature sensor installed on the spray gun is 1400°C with a measurement accuracy of ±2°C. The travel of the telescopic system is 4 meters.

[0037] During the entire spraying process, the control system automatically controls the telescopic system to adjust the gun position based on the real-time predicted steel liquid level and the temperature information fed back by the temperature sensor installed on the spray gun, so as to ensure that the spray gun is always kept at a position of 300~600mm above the steel slag interface during the entire spraying process; At the beginning of smelting, the spray gun is in the initial retraction position. At a certain moment in the smelting process, the temperature sensor shows that the gun body temperature is 810℃. The control system calculates the specific retraction distance based on the following data and formula: At this time, the real-time height of the steel liquid level 1200mm, the spray gun has slid away 1200mm, A gear is 400mm, according to formula 1: It is calculated that the spray gun needs to retract 200mm at this time, and then the telescopic system is instructed to retract to position A. After staying in position A for 5 minutes, the gun body temperature drops to 790℃ and the retraction action stops.

[0038] Compared with the traditional biochar injection technology, the use of this method can reduce the amount of biochar injection by 2kg / ton of steel (the actual injection amount is 25kg / ton of steel), shorten the electric furnace smelting time by 3min, and reduce the power consumption by 6kWh / ton of steel.

[0039] Example 2 This embodiment provides a 90t electric arc furnace full scrap steel smelting process, and the injected biochar is solid wood biochar. The biochar has a fixed carbon content of 80%, an ash content of 5%, a moisture content of 3%, and a particle size of 3mm.

[0040] The biochar spray gun is installed at the furnace door. The initial position is that the muzzle is 600mm away from the outside of the furnace door. The installation angle is 45°. When the spray gun is in the initial position, the height of the muzzle from the bottom of the electric furnace molten pool is 2200mm.

[0041] During the smelting process Obtained by: 1. Use SolidWorks software to build a 3D full-size geometric model of the arc furnace molten pool. Use the volume calculation function of the software to adjust the steel liquid level in the geometric model to calculate the volume of the steel liquid corresponding to different steel liquid heights. The steel liquid level changes in 40mm increments. 2. Import the molten steel volume data calculated in SolidWorks software into Matlab or Python software for data fitting analysis to determine the molten steel level height Furthermore, by expressing the volume of molten steel as the ratio of the weight of molten steel to its density, the height of the molten steel level is derived. The quantitative relationship between the density of molten steel and the weight of molten steel. The density of molten steel is set to 7.2g / cm³. If the amount of scrap steel added is 50t, the weight of molten steel is 50t.

[0042] 3. During the smelting process, the control system calculates the amount of scrap steel added and the set steel liquid density value in real time through the quantitative relationship. .

[0043] Furnace geometry, steel level The mathematical relationship between the density and weight of the molten steel is calibrated regularly once every 260 smelting cycles. The maximum measuring temperature of the temperature sensor installed on the spray gun is 1500°C with a measurement accuracy of ±3°C. The travel of the telescopic system is 5 meters.

[0044] During the entire spraying process, the control system automatically controls the telescopic system to adjust the gun position based on the real-time predicted steel liquid level and the temperature information fed back by the temperature sensor installed on the spray gun, so as to ensure that the spray gun is always kept at a position of 300~600mm above the steel slag interface during the entire spraying process; At the beginning of smelting, the spray gun is in the initial retraction position. At a certain moment in the smelting process, the temperature sensor shows that the gun body temperature is 820℃. The control system calculates the specific retraction distance based on the following data and formula: At this time, the real-time height of the steel liquid level 900mm, the spray gun has slid away 1414mm, A gear is 400mm, according to formula 1: Calculation shows that the spray gun needs to retract 141mm at this time, and then the telescopic system is instructed to retract to position A. After staying in position A for 4 minutes, the gun body temperature is 810℃.

[0045] At this time, the real-time height of the steel liquid level 900mm, the spray gun has slid away 1273mm, B gear is 500mm, according to formula 1: Calculation shows that the spray gun needs to retract 142mm at this time, and then the telescopic system retracts to position B. After staying in position B for 4 minutes, the gun body temperature drops to 790℃ and stops retracting.

[0046] Compared with the traditional biochar injection technology, the use of this method can reduce the amount of biochar injection by 3kg / ton of steel (the actual injection amount is 22kg / ton of steel), shorten the electric furnace smelting time by 4min, and reduce the power consumption by 8kWh / ton of steel.

[0047] Example 3 This embodiment provides a 100t electric arc furnace scrap steel + 30% direct reduced iron smelting process, the iron content of the direct reduced iron is 94%. The injected biochar is coconut shell biochar. The biochar has a fixed carbon content of 88%, an ash content of 2%, a moisture content of 3%, and a particle size of 1 mm.

[0048] The biochar spray gun is installed on the furnace top. The initial position is that the muzzle is 300mm away from the outside of the furnace cover. When the spray gun is in the initial position, the height of the muzzle from the bottom of the electric furnace molten pool is 4200mm.

[0049] During the smelting process Obtained by: 1. Use SolidWorks software to build a 3D full-size geometric model of the arc furnace molten pool. Use the volume calculation function of the software to adjust the steel liquid level in the geometric model to calculate the volume of the steel liquid corresponding to different steel liquid heights. The steel liquid level changes in 20mm increments. 2. Import the molten steel volume data calculated in SolidWorks software into Matlab or Python software for data fitting analysis to determine the molten steel level height Furthermore, by expressing the volume of molten steel as the ratio of the weight of molten steel to its density, the height of the molten steel level is derived. The quantitative relationship between the density of molten steel and the weight of molten steel. The density of molten steel is set to 7.2g / cm³. If the amount of scrap steel added is 40t and the amount of direct reduced iron added is 10t, the weight of molten steel is 49.4t.

[0050] 3. During the smelting process, the control system calculates the amount of scrap steel added and the set steel liquid density value in real time through the quantitative relationship. .

[0051] Furnace geometry, steel level The mathematical relationship between the density and weight of the molten steel is calibrated regularly every 300 smelting cycles. The maximum measuring temperature of the temperature sensor installed on the spray gun is 1600°C with a measurement accuracy of ±3°C. The travel of the telescopic system is 3 meters.

[0052] During the entire spraying process, the control system automatically controls the telescopic system to adjust the gun position based on the real-time predicted steel liquid level and the temperature information fed back by the temperature sensor installed on the spray gun, so as to ensure that the spray gun is always kept at a position of 300~600mm above the steel slag interface during the entire spraying process; At the beginning of smelting, the spray gun is in the initial retraction position. is 300mm, at this time, S 理论is 0, calculated by formula 1, the spray gun has slid a distance At a certain moment in the smelting process, the temperature sensor shows that the gun body temperature is 815°C. The control system calculates the specific retraction distance based on the following data and formula: At this time, the real-time height of the steel liquid level 1000mm, the spray gun has slid distance 2900mm, A gear is 400mm, according to formula 1: It is calculated that the spray gun needs to retract 100mm at this time, and then the telescopic system is instructed to retract to position A. After staying in position A for 3 minutes, the gun body temperature is 830℃.

[0053] At this time, the real-time height of the steel liquid level 1100mm, the spray gun has slid away 2800mm, B position is 500mm, according to formula 1: Calculation shows that the spray gun needs to retract 200mm at this time, and then the telescopic system retracts to position B. After staying in position B for 3 minutes, the gun body temperature drops to 820℃.

[0054] At this time, the real-time height of the steel liquid level 1100mm, the spray gun has slid away 2600mm, C position is 600mm, according to formula 1: It is calculated that the spray gun needs to retract 100mm at this time, and then the telescopic system retracts to the C position. After staying in the C position for 3 minutes, the gun body temperature drops to 795℃ and stops retracting.

[0055] Compared with the traditional biochar injection technology, the use of this method can reduce the amount of biochar injection by 4kg / ton of steel (the actual injection amount is 24kg / ton of steel), shorten the electric furnace smelting time by 5min, and reduce the power consumption by 10kWh / ton of steel.

[0056] Comparative Example 1 This comparative example provides a 120t electric arc furnace scrap steel + 30% molten iron smelting process, and the injected biochar is corn straw biochar. The biochar has a fixed carbon content of 75%, an ash content of 13%, a moisture content of 2%, and a particle size of 2mm.

[0057] The biochar spray gun is fixedly installed on the furnace wall. The initial position is that the muzzle is 200 mm away from the furnace wall surface. The installation angle is 30°. The height of the muzzle of the spray gun from the bottom of the electric furnace molten pool is 2100 mm. Biochar is continuously sprayed during the smelting process.

[0058] The amount of biochar injected during the entire smelting process was 27 kg / ton of steel. Compared with Example 1, the use of this method will increase the amount of biochar injected by 2 kg / ton of steel, increase the electric furnace smelting time by 3 min, and increase the power consumption by 6 kWh / ton of steel.

[0059] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present application, rather than to limit it. Although the present application has been described in detail with reference to the aforementioned embodiments, those skilled in the art should understand that they can still modify the technical solutions described in the aforementioned embodiments, or replace some or all of the technical features therein with equivalents. However, these modifications or replacements do not cause the essence of the corresponding technical solutions to deviate from the scope of the technical solutions of the embodiments of the present application.

Claims

1. A low-carbon emission steelmaking method, characterized in that: include: The biochar is sprayed into the steel slag by a spray gun, wherein the spray gun is ensured by a telescopic system that its outlet is always located 300-600 mm above the interface between the molten steel and the steel slag and is located within the steel slag; The telescopic system controls the movement distance of the spray gun to satisfy the following formula 1: ； in, is the distance that the spray gun should be retracted; is the height from the muzzle to the bottom of the molten pool when the spray gun is in the initial position; The real-time height of the steel liquid level; The vertical distance between the outlet of the spray gun and the steel liquid surface; θ is the installation angle of the spray gun. The angle of the spray gun at the furnace wall and furnace door is defined as the angle between the tail of the spray gun and the direction of the gun head and the horizontal line. The angle of the spray gun at the furnace top is 90 degrees. is the distance the spray gun has moved; When the gun body temperature of the spray gun is greater than or equal to the control temperature, the telescopic system controls the spray gun to perform a retraction action, and then after staying for a preset time, if the gun body temperature of the spray gun drops below the control temperature, the position of the spray gun is kept unchanged; if the gun body temperature of the spray gun does not drop below the control temperature, it continues to retract until the gun body temperature of the spray gun is lower than the control temperature.

2. The low-carbon emission steelmaking method according to claim 1, characterized in that: Said Obtained by: A 3D full-size geometric model of the arc furnace molten pool was established. By adjusting the molten steel level in the geometric model, the volume of molten steel corresponding to different molten steel heights was calculated. The molten steel level height was adjusted in increments of 10 mm to 50 mm. The calculated molten steel volume data is subjected to data fitting analysis to determine the molten steel level height. Mathematical relationship model between the volume of molten steel and the By expressing the volume of molten steel as the ratio of its weight to its density, the height of the molten steel level can be derived. The quantitative relationship between the density of the molten steel and the weight of the molten steel; the weight of the molten steel is calculated based on the amount of iron-containing raw materials added to the electric arc furnace; During the smelting process, according to the amount of iron-containing raw materials added and the set steel liquid density value, the quantitative relationship is used to calculate the .

3. The low-carbon emission steelmaking method according to claim 2, characterized in that: The quantitative relationship needs to be calibrated regularly within 200-300 smelting cycles.

4. The low-carbon emission steelmaking method according to claim 1, characterized in that: The gun body temperature of the spray gun is measured by a temperature sensor; The temperature sensor is installed between the biochar powder spray pipe and the water cooling jacket of the spray gun; The maximum measurement temperature of the temperature sensor is not less than 1300°C, and the measurement accuracy is ±3°C.

5. The low-carbon emission steelmaking method according to claim 1, characterized in that: The telescopic system controls the movement distance of the spray gun along its movement direction to be 3-5 meters; The moving distance is measured by a displacement sensor.

6. The low-carbon emission steelmaking method according to claim 1, characterized in that: The retraction action includes at least 3 gears, corresponding to They are 400mm, 500mm and 600mm respectively.

7. The low-carbon emission steelmaking method according to claim 1, characterized in that: The installation position of the spray gun includes any one of the outer side of the electric furnace wall, the electric furnace door and the electric furnace top; The initial position of the spray gun arranged on the outer side of the electric furnace wall is that the muzzle is 150-300mm away from the furnace wall surface; the initial position of the spray gun arranged on the electric furnace door is that the muzzle is 500-1000mm away from the outside of the furnace door; the initial position of the spray gun arranged on the electric furnace top is that the muzzle is 300-800mm away from the outer side of the furnace cover.

8. The low-carbon emission steelmaking method according to claim 1, characterized in that: The controlled temperature is not higher than 800°C.

9. The low-carbon emission steelmaking method according to any one of claims 1 to 8, characterized in that: The spraying amount of the biochar sprayed by the spray gun is 15-25kg / ton of steel.

10. A low-carbon emission steelmaking system, characterized in that: Used to implement the low-carbon emission steelmaking method according to any one of claims 1 to 9; The low-carbon emission steelmaking system includes an electric furnace, a spray gun, a telescopic mechanism and a control system. The spray gun is arranged at any position of the outer side of the electric furnace wall, the electric furnace door and the electric furnace top. The spray gun is connected to the mobile module in the telescopic mechanism. The control system is used to receive data, process data and control the mobile module according to the data processing results, thereby controlling the spray gun to move away from or approach the interface between molten steel and slag in the electric furnace.

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