Feeding method and system for electric arc furnace using direct reduction iron

Abstract

The invention provides a charging method and system for an electric arc furnace using direct reduction iron, and belongs to the field of electric arc furnace steelmaking. The method comprises the following steps: acquiring smelting plan data, original material data and smelting working condition data of a current heat of an electric arc furnace according to an actual production plan, acquiring a real-time image of a molten steel area of the electric arc furnace, and then calculating the temperature of molten steel and the temperature of a direct reduction iron melting area; comparing the temperature of the melting area with the melting temperature T2 and the solidification temperature T1 of the direct reduction iron; when the temperature of the direct reduction iron melting area is smaller than or equal to T1 or larger than or equal to T2, energy balance calculation is conducted on the melting area according to the smelting plan data, the smelting working condition data, the molten steel temperature and the temperature of the direct reduction iron melting area, and the current theoretical feeding speed is obtained; and the current actual feeding speed is adjusted according to the current theoretical feeding speed, and the current actual feeding speed is adjusted to be the current theoretical feeding speed. The matching effect of charging and smelting equipment and process is improved.

Description

Technical fields:

[0001] This invention belongs to the field of electric arc furnace steelmaking, specifically relating to a feeding method and system for using direct reduced iron in an electric arc furnace. Background technology:

[0002] Direct reduced iron (DRI) is a high-metallization iron-containing material obtained by reducing iron pellets in a shaft furnace using hydrogen-rich or pure hydrogen gas. The production process has low carbon emissions and residual elements, making it an ideal raw material for replacing some scrap steel in electric arc furnace (EAF) steelmaking processes. In the smelting process of DRI in an EAF, the matching between the charging rate of the EAF and the smelting process has a significant impact on production efficiency. If the charging rate is too fast, an iceberg effect can easily form, hindering the melting process; while if the charging rate is too slow, it will lead to a prolonged smelting cycle and excessive energy consumption.

[0003] In existing technologies, the conventional solutions to the charging control problem of direct reduced iron (DRI) in electric arc furnaces are to enhance the oxygen supply and carbon injection in the DRI charging zone to provide additional chemical energy to this area, using furnace wall burners to target the DRI charging area to enhance the blowing effect, accelerate melting, and improve smelting efficiency; or using external preheating devices to heat the DRI or directly using hot DRI for smelting. However, all of these methods focus on increasing energy input to improve the melting rate of DRI. But facing the high-temperature, complex, and variable conditions of the molten pool, operators cannot accurately monitor the charging situation of DRI. Simply increasing the intensity of oxygen supply and carbon injection will lead to over-oxidation of the molten steel, unstable thermal balance in the furnace, low metal yield, and serious energy consumption. Excessive use of carbon powder also further increases CO2 emissions, failing to achieve the effect of reducing carbon emissions from DRI.

[0004] For example, Chinese patent CN118996046A discloses a dynamic control method and system for steelmaking using direct reduced iron in an electric arc furnace. By coordinating the processes of charging, power supply, oxygen supply, and carbon injection, it achieves efficient smelting of direct reduced iron in the electric arc furnace. However, it still cannot dynamically control the charging speed and energy input intensity of direct reduced iron, cannot monitor the melting effect in the charging zone, and cannot prevent the occurrence of the iceberg effect or excessive oxidation. Chinese patent CN101775460A discloses a method using coal-based direct reduced iron as raw material, utilizing auxiliary energy supply from carbon-containing materials such as waste electrodes, low-S coke, and anthracite, along with power supply operation and oxygen blowing to enhance the melting effect of coal-based direct reduced iron. While this method can also guarantee the melting effect of direct reduced iron, it is heavily dependent on carbon-containing materials, has high energy consumption, and large carbon emissions, failing to reduce carbon emissions. Summary of the Invention:

[0005] To address the aforementioned problems, this invention provides a method and system for charging direct reduced iron (DRI) in an electric arc furnace. While ensuring the smelting effect of DRI, it achieves an optimized match between the charging speed and the energy replenishment intensity of DRI, thereby reducing energy consumption and carbon emissions, shortening the smelting cycle, and improving production efficiency.

[0006] To achieve the above objectives, the technical solutions adopted in the embodiments of the present invention are as follows:

[0007] In a first aspect, embodiments of the present invention provide a method for charging direct reduced iron in an electric arc furnace, the method comprising the following steps:

[0008] Step S1: Obtain the smelting plan data, raw material data and smelting condition data of the current furnace batch of the electric arc furnace according to the actual production plan;

[0009] Step S2: Obtain a real-time image of the molten steel zone in the electric arc furnace;

[0010] Step S3: Recognize the real-time image and obtain the molten steel temperature and directly reconstruct the temperature of the iron melting zone based on the image;

[0011] Step S4: Compare the relationship between the direct reduced iron melting zone temperature and the direct reduced iron melting temperature and solidification temperature; when the direct reduced iron melting zone temperature is less than or equal to T1 or greater than or equal to T2, proceed to step S5; if the direct reduced iron melting zone temperature is less than T1 and greater than T2, proceed to step S8.

[0012] Step S5: Based on the smelting plan data, smelting condition data, molten steel temperature and direct reduced iron melting zone temperature, perform energy balance calculation on the melting zone to obtain the current theoretical feeding rate of direct reduced iron.

[0013] Step S6: Adjust the current actual feeding rate according to the current theoretical feeding rate, adjust the current actual feeding rate to the current theoretical feeding rate, and execute the feeding operation for the current furnace; proceed to step S8;

[0014] Step S7: Perform the feeding operation for the current furnace based on the current actual feeding rate;

[0015] Step S8: Determine whether the feeding is complete; if not, proceed to step S2; if complete, end the feeding process.

[0016] As a preferred embodiment of the present invention, the electric arc furnace includes any one of the following: a top-charged electric arc furnace of 50-300t, a continuously fed electric arc furnace, and a vertical shaft electric arc furnace.

[0017] In a preferred embodiment of the present invention, the smelting plan data includes the composition of direct reduced iron and the amount of direct reduced iron used.

[0018] In a preferred embodiment of the present invention, the original material data includes the solidification temperature T1 and the melting temperature T2 of direct reduced iron.

[0019] In a preferred embodiment of the present invention, the smelting condition data includes the electric arc furnace power supply, carbon injection rate, and gas flow rate.

[0020] As a preferred embodiment of the present invention, the formulas for calculating the solidification temperature T1 and melting temperature T2 of direct reduced iron are as follows:

[0021]

[0022] In equations (1) and (2), T1 is the solidification temperature of direct reduced iron, T2 is the melting temperature of direct reduced iron, and k is the solidification temperature of direct reduced iron. i k represents the decrease in solidification temperature when the content of a certain element i increases by 1%. j Let a1 be the increase in melting temperature when the content of a certain element j increases by 1%, where a1 is the content of element i or j in direct reduced iron; p is the total number of element i; and q is the total number of element j.

[0023] In a preferred embodiment of the present invention, step S3 obtains the steel temperature and the direct reduced iron melting zone temperature from the image using the following formula:

[0024]

[0025] In equations (3) and (4), c1 is the average temperature of the molten steel, T i Let n be the temperature of the i-th pixel in the molten steel. c1 C1 represents the number of cells containing molten steel, C2 represents the average temperature of the direct reduced iron melting zone, and T represents the temperature of the molten steel. j To directly restore the temperature of the j-th pixel in the molten iron zone, n c2 To directly restore the number of cells in the iron melting zone.

[0026] In a preferred embodiment of the present invention, the formula for calculating the current theoretical feeding rate of direct reduced iron in step S5 is as follows:

[0027] Q E =[b1]·t·η E ·ε E (5)

[0028] Q C = [b2]·t·△H C ·η C ·ε C (6)

[0029] Q Gas = [b3]·t·△H Gas·η Gas ·ε Gas (7)

[0030]

[0031] In equations (5) to (9), Q E The heat provided by electrical energy, η4 is the efficiency of converting electrical energy into heat energy, and ε E The efficiency of electrical energy transfer of heat to direct reduced iron; Q C The heat provided by carbon oxidation, η C It is the carbon utilization rate, ΔH C It is the heat released by the oxidation of carbon per unit mass, ε C The efficiency of heat transfer from carbon oxidation to direct reduced iron; Q Gas It is the heat provided by the combustion of combustible gas, η Gas It is the gas utilization rate, △H Gas It is the heat released by the oxidation of a unit mass of fuel gas, ε Gas The efficiency of heat transfer from combustion of the gas to direct reduced iron; t is the power supply time, b1 is the power supply of the electric arc furnace, b2 is the carbon injection rate of the electric arc furnace, b3 is the gas flow rate of the electric arc furnace; Q Steel For contact heat transfer between molten steel and direct reduced iron, c1 is the average temperature of the molten steel, c2 is the average temperature of the direct reduced iron melting zone, and R is the thermal resistance; γ steel It is the heat utilization coefficient of direct reduced iron; c p ΔT is the specific heat capacity of direct reduced iron, ΔT is the difference between the melting point T2 of direct reduced iron and the actual melting zone temperature c2, and L is the latent heat of fusion of direct reduced iron.

[0032] Secondly, embodiments of the present invention also provide a charging system for direct reduced iron (DRI) in an electric arc furnace. The system includes: smelting equipment 1, a charging device 2, an image capture device 3, and a computer control subsystem 4. The smelting equipment 1 includes a furnace body 11, electrodes 12, a gas lance 13, a carbon lance 14, a gas flow sensor 15, and a carbon powder quality sensor 16. The charging device 2 includes a hopper 21, a weighing device 22, a conveying device 23, and a charging speed controller 24. The image capture device 3 includes an industrial camera 31, an external water-cooling device 32, and a data transmission interface 33. The computer control subsystem 4 includes a data acquisition module 41, an image recognition module 42, a temperature comparison module 43, a theoretical charging speed calculation module 44, and a speed control module 45.

[0033] The data acquisition module 41 is connected to the temperature comparison module 43 and the theoretical charging rate calculation module 44. It is used to acquire the smelting plan data, raw material data and smelting condition data of the current furnace of the electric arc furnace according to the actual production plan, and send the raw material data to the temperature comparison module 43, and send the smelting plan data and smelting condition data to the theoretical charging rate calculation module 44.

[0034] The image recognition module 42 is connected to the data transmission interface 33 of the image recognition device 3, and is also connected to the temperature comparison module 43 and the speed control module 45. It is used to receive real-time images of the molten steel zone of the electric arc furnace acquired by the image capture device, and to recognize the real-time images. Based on the images, the temperature of the molten steel and the temperature of the iron melting zone are obtained and sent to the temperature comparison module 43 and the speed control module 45.

[0035] The temperature comparison module 43 is connected to the theoretical feeding rate calculation module 44 and is used to compare the relationship between the temperature of the direct reduced iron melting zone and the direct reduced iron melting temperature and solidification temperature. When the temperature of the direct reduced iron melting zone is less than or equal to T1 or the temperature of the direct reduced iron melting zone is greater than or equal to T2, the theoretical feeding rate calculation module 44 is activated.

[0036] The theoretical feeding rate calculation module 44 is connected to the speed control module 45. It is used to perform energy balance calculation on the melting zone based on smelting plan data, smelting condition data, molten steel temperature and direct reduced iron melting zone temperature, to obtain the current theoretical feeding rate of direct reduced iron, and send it to the speed control module 45.

[0037] The speed control module 45 is connected to the feeding speed controller 24 of the feeding device. It is used to adjust the current actual feeding speed according to the current theoretical feeding speed, adjust the current actual feeding speed to the current theoretical feeding speed, and send it to the feeding speed controller 24.

[0038] In a preferred embodiment of the present invention, the image capture device 3 is disposed on the upper part of the eccentric bottom tapping EBT device in the smelting equipment, and is equipped with a high-definition lens, the lens range of which can cover the entire surface of the molten steel.

[0039] The solutions of the embodiments of the present invention have the following beneficial effects:

[0040] The electric arc furnace charging method and system for direct reduced iron (DRI) provided in this invention uses an energy balance calculation model combined with DRI melting state data obtained through image recognition to dynamically adjust the charging speed of DRI, achieving a match between the melting speed, charging speed, and energy replenishment intensity. By better matching the charging with the smelting equipment and process based on the energy balance within the electric arc furnace, efficient DRI smelting is achieved, accelerating the smelting pace, improving smelting efficiency, increasing energy utilization, reducing carbon emissions, lowering production costs, and shortening the smelting cycle. Furthermore, it is easy to operate, highly automated, and can realize large-scale industrial production.

[0041] Of course, implementing any product or method of the present invention does not necessarily require achieving all of the advantages described above at the same time. Attached image description:

[0042] To more clearly illustrate the technical solutions in the embodiments of the present invention, the accompanying drawings used in the description of the embodiments will be briefly introduced below. Obviously, the accompanying drawings described below are only some embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0043] Figure 1 This is a flowchart illustrating the charging method for direct reduced iron in an electric arc furnace according to an embodiment of the present invention.

[0044] Figure 2 This is a schematic diagram of the feeding system for the electric arc furnace using direct reduced iron according to an embodiment of the present invention.

[0045] Explanation of reference numerals in the attached figures:

[0046] 1-Smelting equipment; 2-Feeding device; 3-Image capture device; 4-Computer control subsystem; 11-Furnace body; 12-Electrode; 13-Gas gun; 14-Carbon gun; 15-Gas flow sensor; 16-Carbon powder quality sensor; 21-Hopper; 22-Weighing device; 23-Conveying device; 24-Feeding speed controller; 31-Industrial camera; 32-External water cooling equipment; 33-Data transmission interface; 41-Data acquisition module; 42-Image recognition module; 43-Temperature comparison module; 44-Theoretical feeding speed calculation module; 45-Speed ​​control module. Detailed implementation method:

[0047] The technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only a part of the embodiments of the present invention, and not all of them. The components of the embodiments of the present invention described and shown in the accompanying drawings can generally be arranged and designed in various different configurations. It should be noted that, without conflict, the embodiments and features in the embodiments of the present invention can also be combined with each other.

[0048] It should be noted that similar reference numerals and letters in the following figures indicate similar items; therefore, once an item is defined in one figure, it does not need to be further defined and explained in subsequent figures. In the description of this invention, the terms "first," "second," "third," "fourth," etc., are used only to distinguish descriptions and should not be construed as indicating or implying relative importance.

[0049] To address the charging problem of direct reduced iron (DRI) in electric arc furnaces, this invention provides a charging method and system for DRI in electric arc furnaces. The system includes acquiring smelting plan data, real-time smelting parameters, and DRI melting zone image data; inputting power supply, carbon injection rate, gas flow rate, molten steel temperature, and DRI melting zone temperature to perform material and energy balance calculations for DRI melting; outputting a DRI charging rate matching the energy replenishment intensity; and dynamically controlling the DRI charging rate until the end of the furnace cycle. This invention, based on image recognition technology, dynamically controls DRI charging, further reducing energy and raw material consumption and improving production efficiency while meeting target steel temperature, composition, and quality requirements. This invention is highly efficient, easy to operate, and highly automated, making it suitable for large-scale industrial production.

[0050] like Figure 1 As shown, the electric arc furnace described in this embodiment uses a direct reduced iron charging method, which includes the following steps:

[0051] Step S1: Obtain the smelting plan data, raw material data, and smelting condition data for the current furnace batch of the electric arc furnace based on the actual production plan.

[0052] In this step, the smelting plan data includes the composition and amount of direct reduced iron (DRI), and the raw material data includes the DRI solidification temperature T1 and the DRI melting temperature T2. The smelting operating condition data includes the electric arc furnace power supply, carbon injection rate, and gas flow rate. The electric arc furnace mentioned here includes any one of the following: a 50-300t top-charge electric arc furnace, a continuously charged electric arc furnace, or a vertical shaft electric arc furnace.

[0053] The formulas for calculating the solidification temperature T1 and melting temperature T2 of direct reduced iron are as follows:

[0054]

[0055] In equations (1) and (2), T1 is the solidification temperature of direct reduced iron, T2 is the melting temperature of direct reduced iron, and k is the solidification temperature of direct reduced iron. i k represents the decrease in solidification temperature when the content of a certain element i increases by 1%. j Let a1 be the increase in melting temperature when the content of a certain element j increases by 1%, where a1 is the content of element i or j in direct reduced iron; p is the total number of element i; and q is the total number of element j.

[0056] Step S2: Obtain a real-time image of the molten steel zone in the electric arc furnace.

[0057] In this step, the equipment used to acquire real-time images includes infrared, thermal imaging, and / or industrial cameras with temperature measurement capabilities.

[0058] Step S3: Recognize the real-time image and obtain the molten steel temperature and the temperature of the iron melting zone directly from the image.

[0059] In this step, the steel temperature and the direct reduction iron melting zone temperature are obtained from the image using the following formulas:

[0060]

[0061] In equations (3) and (4), c1 is the average temperature of the molten steel, T i Let n be the temperature of the i-th pixel in the molten steel. c1 C1 represents the number of cells containing molten steel, C2 represents the average temperature of the direct reduced iron melting zone, and T represents the temperature of the molten steel. j To directly restore the temperature of the j-th pixel in the molten iron zone, n c2 To directly restore the number of cells in the iron melting zone.

[0062] Step S4: Compare the relationship between the direct reduced iron melting zone temperature and the direct reduced iron melting temperature and solidification temperature; when the direct reduced iron melting zone temperature is less than or equal to T1 or greater than or equal to T2, proceed to step S5; if the direct reduced iron melting zone temperature is less than T1 and greater than T2, proceed to step S7.

[0063] In this step, the temperatures c2, T1, and T2 in the direct reduced iron melting zone are compared. When c2 is less than or equal to T1, the feeding rate in this zone is considered too fast, resulting in an iceberg effect; when c2 is greater than or equal to T2, the feeding rate is considered too slow, resulting in over-oxidation. In these cases, the feeding rate needs to be adjusted.

[0064] Step S5: Based on the smelting plan data, smelting condition data, molten steel temperature, and direct reduced iron melting zone temperature, perform energy balance calculations on the melting zone to obtain the current theoretical feeding rate of direct reduced iron.

[0065] In this step, the formula for calculating the current theoretical feeding rate of direct reduced iron is as follows:

[0066] Q E =[b1]·t·η E ·ε E (5)

[0067] Q C = [b2]·t·△H C ·η C ·ε C (6)

[0068] Q Gas = [b3]·t·△H Gas ·η Gas ·ε Gas (7)

[0069]

[0070] In equations (5) to (9), Q E The heat provided by electrical energy, η E ε represents the efficiency of converting electrical energy into heat energy. E The efficiency of electrical energy transfer of heat to direct reduced iron; Q C The heat provided by carbon oxidation, η C It is the carbon utilization rate, ΔH C It is the heat released by the oxidation of carbon per unit mass, ε C The efficiency of heat transfer from carbon oxidation to direct reduced iron; Q Gas It is the heat provided by the combustion of combustible gas, η Gas It is the gas utilization rate, △H Gas It is the heat released by the oxidation of a unit mass of fuel gas, ε Gas The efficiency of heat transfer from combustion of the gas to direct reduced iron; t is the power supply time, b1 is the power supply of the electric arc furnace, b2 is the carbon injection rate of the electric arc furnace, b3 is the gas flow rate of the electric arc furnace; Q Steel For contact heat transfer between molten steel and direct reduced iron, c1 is the average temperature of the molten steel, c2 is the average temperature of the direct reduced iron melting zone, and R is the thermal resistance; γ steel It is the heat utilization coefficient of direct reduced iron; c p ΔT is the specific heat capacity of direct reduced iron, ΔT is the difference between the melting point T2 of direct reduced iron and the actual melting zone temperature c2, and L is the latent heat of fusion of direct reduced iron.

[0071] This step calculates the current theoretical feeding rate of direct reduced iron through energy balance calculations, based on the law of conservation of matter and energy. Therefore, the calculated results are more consistent with actual production, allowing for more precise adjustment of the direct reduced iron feeding rate, avoiding unnecessary energy consumption in smelting, shortening the smelting cycle, greatly saving smelting costs, and improving economic efficiency.

[0072] Step S6: Adjust the current actual feeding rate according to the current theoretical feeding rate, adjust the current actual feeding rate to the current theoretical feeding rate, and execute the feeding operation for the current furnace. Proceed to step S8.

[0073] Step S7: Perform the feeding operation for the current furnace based on the current actual feeding rate.

[0074] Step S8: Determine whether the feeding is complete; if not, proceed to step S2; if complete, end the feeding process.

[0075] Based on the same idea, embodiments of the present invention also provide a charging system for direct reduced iron in an electric arc furnace. For example... Figure 2 As shown, the system includes: smelting equipment 1, feeding device 2, image capture device 3, and computer control subsystem 4; wherein, the smelting equipment 1 includes furnace body 11, electrode 12, gas gun 13, carbon gun 14, gas flow sensor 15, and carbon powder quality sensor 16; the feeding device 2 includes hopper 21, weighing device 22, conveying device 23, and feeding speed controller 24; the image capture device 3 includes industrial camera 31, peripheral water cooling device 32, and data transmission interface 33; the computer control subsystem 4 includes data acquisition module 41, image recognition module 42, temperature comparison module 43, theoretical feeding speed calculation module 44, and speed control module 45; wherein,

[0076] The data acquisition module 41 is connected to the temperature comparison module 43 and the theoretical charging rate calculation module 44. It is used to acquire the smelting plan data, raw material data and smelting condition data of the current furnace batch of the electric arc furnace according to the actual production plan, and send the raw material data to the temperature comparison module 43, and send the smelting plan data and smelting condition data to the theoretical charging rate calculation module 44. The data acquisition module 41 can input the collected data through the display device.

[0077] The image recognition module 42 is connected to the data transmission interface 33 of the image recognition device 3, and is also connected to the temperature comparison module 43 and the theoretical feeding rate calculation module 44. It is used to receive real-time images of the molten steel zone of the electric arc furnace acquired by the image capture device, and to recognize the real-time images. Based on the images, it obtains the molten steel temperature and the direct reduction iron melting zone temperature, and simultaneously sends them to the temperature comparison module 43 and the theoretical feeding rate calculation module 44. The image recognition module 42 can be connected to the data transmission interface 33 through a hub or the like.

[0078] The temperature comparison module 43 is connected to the theoretical feeding rate calculation module 44 and is used to compare the relationship between the temperature of the direct reduced iron melting zone and the direct reduced iron melting temperature and solidification temperature. When the temperature of the direct reduced iron melting zone is less than or equal to T1 or the temperature of the direct reduced iron melting zone is greater than or equal to T2, the theoretical feeding rate calculation module 44 is activated.

[0079] The theoretical feeding rate calculation module 44 is connected to the speed control module 45. It is used to perform energy balance calculation on the melting zone based on smelting plan data, smelting condition data, molten steel temperature and direct reduced iron melting zone temperature, to obtain the current theoretical feeding rate of direct reduced iron, and send it to the speed control module 45.

[0080] The speed control module 45 is connected to the feeding speed controller 24 of the feeding device. It is used to adjust the current actual feeding speed according to the current theoretical feeding speed, adjust the current actual feeding speed to the current theoretical feeding speed, and send it to the feeding speed controller 24. The speed control module 45 can control the feeding speed controller 24 through the control cabinet, etc.

[0081] Preferably, in this embodiment of the invention, the image capture device 3 is disposed on the upper part of the eccentric bottom tapping (EBT) device in the smelting equipment, and is equipped with a high-definition lens, the lens range of which can cover the entire surface of the molten steel.

[0082] In this embodiment, each module is implemented using a processor, with additional memory added as needed for storage. The processor can be, but is not limited to, a microprocessor (MPU), a central processing unit (CPU), a network processor (NP), a digital signal processor (DSP), an application-specific integrated circuit (ASIC), a field-programmable gate array (FPGA), a programmable logic controller (PLC), other programmable logic devices, discrete gates, transistor logic devices, discrete hardware components, etc. The memory can include random access memory (RAM) or non-volatile memory (NVM), such as at least one disk storage device. Optionally, the memory can also be at least one storage device located remotely from the aforementioned processor.

[0083] In the above embodiments, implementation can be achieved, in whole or in part, through software, hardware, firmware, or any combination thereof. When implemented in software, it can be implemented, in whole or in part, as a computer program product. The computer program product includes one or more computer instructions. When the computer program instructions are loaded and executed on a computer, all or part of the processes or functions described in the embodiments of the present invention are generated. The computer can be a general-purpose computer, a special-purpose computer, a computer network, or other programmable device. The computer instructions can be stored in a computer-readable storage medium or transmitted from one computer-readable storage medium to another. For example, the computer instructions can be transmitted from one website, computer, server, or data center to another website, computer, server, or data center via wired (e.g., coaxial cable, fiber optic, digital subscriber line (DSL)) or wireless (e.g., infrared, wireless, microwave, etc.) means.

[0084] It should also be noted that the electric arc furnace charging system for direct reduced iron described in this embodiment corresponds to the electric arc furnace charging method for direct reduced iron. The description and limitations of the method also apply to the system, and will not be repeated here.

[0085] The method and system for charging direct reduced iron (DRI) in an electric arc furnace according to the embodiments of the present invention were applied to the actual production of a 120t top-charged electric arc furnace. Low-carbon steel was smelted using 20% ​​DRI and 80% scrap steel as raw materials. The electric arc furnace had three gas burners and two biomass charcoal powder spray guns on the furnace wall. The DRI composition was 1.79% C, 0.09% Mn, 0.007% P, 3.11% SiO2, 0.77% Al2O3, 0.341% CaO, 0.62% MgO, and 5.78% FeO. The solidification temperature T1 of the DRI was calculated to be 1496℃, and the melting temperature T2 was 1549℃. The planned amount of DRI was 24t. The real-time smelting data and the DRI charging rate during one smelting cycle are shown in Table 1.

[0086] Table 1 Phase Planning Operation Table

[0087]

[0088]

[0089] Capture real-time images of the molten steel zone in the electric arc furnace, and calculate the molten steel temperature and the direct reduced iron melting zone temperature according to formulas (3) and (4); then compare the direct reduced iron melting zone temperature with the solidification temperature and melting temperature, and adjust the feeding speed in real time to match the feeding speed with the smelting equipment and process. The judgment criterion is that the calculated direct reduced iron melting zone temperature is within the range of the solidification temperature and melting temperature. If it is not, calculate the current theoretical feeding speed and adjust the current actual feeding speed to achieve matching.

[0090] The method and system for charging direct reduced iron (DRI) in the electric arc furnace described in this embodiment of the invention were then applied to the actual production of a 250t CONSTEEL electric arc furnace. Low-carbon steel was smelted using 30% DRI and 70% scrap steel as raw materials. The electric arc furnace wall had two biomass gas burners and two carbon powder spray guns. The DRI composition was 3.14% [C], 0.07% [Mn], 0.007% [P], 2.91% SiO2, 0.72% Al2O3, 0.381% CaO, 0.6% MgO, and 5.35% FeO. The calculated solidification temperature T1 was 1491℃, and the melting temperature T2 was 1537℃. The planned DRI usage was 60t. Real-time smelting data and DRI charging rate over one smelting cycle are shown in Table 2.

[0091] Table 2 Phase Planning Operation Table

[0092]

[0093] Performing the same operation, after smelting, both electric arc furnaces achieved steel smelting within 48 minutes, shortening the production cycle, reducing power consumption per ton of steel by more than 9 kWh, shortening the smelting time per furnace by about 10% compared to the traditional process, reducing energy consumption per ton of steel production by more than 27 kgce, reducing CO2 emissions by more than 110 kg, and reducing the cost per ton of steel by more than 18 yuan.

[0094] As can be seen from the above technical solutions, the electric arc furnace charging method and system for direct reduced iron provided in this embodiment of the invention dynamically adjusts the charging speed of direct reduced iron by using an energy balance calculation model combined with the melting state data of direct reduced iron obtained by image recognition. This achieves a match between the melting speed, charging speed, and energy replenishment intensity of direct reduced iron. By better matching the charging with the smelting equipment and process according to the energy balance in the electric arc furnace, efficient melting of direct reduced iron is achieved, accelerating the smelting pace, improving smelting efficiency, increasing energy utilization, reducing carbon emissions, reducing production costs, and shortening the smelting cycle. At the same time, it is easy to operate, highly automated, conducive to industrial production, and suitable for widespread application.

[0095] The above description is merely a preferred embodiment of the present invention and an explanation of the technical principles employed, and is not intended to limit the scope of the claimed invention, but merely to illustrate preferred embodiments of the invention. Those skilled in the art should understand that the scope of the invention is not limited to the specific combinations of the above-described technical features, but should also cover other technical solutions formed by arbitrary combinations of the above-described technical features or their equivalents without departing from the inventive concept. All other embodiments obtained by those skilled in the art based on the embodiments of the present invention without inventive effort are within the scope of protection of the present invention.

Claims

1. A method for charging direct reduced iron in an electric arc furnace, characterized in that, The method includes the following steps: Step S1: Obtain the smelting plan data, raw material data and smelting condition data of the current furnace batch of the electric arc furnace according to the actual production plan; the raw material data includes the solidification temperature T1 and melting temperature T2 of direct reduced iron. Step S2: Obtain a real-time image of the molten steel zone in the electric arc furnace; Step S3: Recognize the real-time image and obtain the molten steel temperature and directly reconstruct the temperature of the iron melting zone based on the image; Step S4: Compare the relationship between the direct reduced iron melting zone temperature and the direct reduced iron melting temperature and solidification temperature; when the direct reduced iron melting zone temperature is less than or equal to T1 or greater than or equal to T2, proceed to step S5; if the direct reduced iron melting zone temperature is less than T1 and greater than T2, proceed to step S8. Step S5: Based on the smelting plan data, smelting condition data, molten steel temperature and direct reduced iron melting zone temperature, perform energy balance calculation on the melting zone to obtain the current theoretical feeding rate of direct reduced iron. Step S6: Adjust the current actual feeding rate according to the current theoretical feeding rate, adjust the current actual feeding rate to the current theoretical feeding rate, and execute the feeding operation for the current furnace; proceed to step S8; Step S7: Perform the feeding operation for the current furnace based on the current actual feeding rate; Step S8: Determine whether the feeding is complete; if not, proceed to step S2; if complete, end the feeding process.

2. The method according to claim 1, characterized in that, The electric arc furnace includes any one of the following: a top-charged electric arc furnace of 50-300t, a continuously fed electric arc furnace, or a vertical shaft electric arc furnace.

3. The method according to claim 1, characterized in that, The smelting plan data includes the composition and amount of direct reduced iron (DRI).

4. The method according to claim 1, characterized in that, The smelting operating data includes the electric arc furnace power supply, carbon injection rate, and gas flow rate.

5. The method according to claim 1, characterized in that, The formulas for calculating the solidification temperature T1 and melting temperature T2 of direct reduced iron are as follows: In equations (1) and (2), T1 is the solidification temperature of direct reduced iron, T2 is the melting temperature of direct reduced iron, and k is the solidification temperature of direct reduced iron. i k represents the decrease in solidification temperature when the content of a certain element i increases by 1%. j Let a1 be the increase in melting temperature when the content of a certain element j increases by 1%, where a1 is the content of element i or j in direct reduced iron; p is the total number of element i; and q is the total number of element j.

6. The method according to claim 1, characterized in that, Step S3: Obtain the steel temperature and the direct reduced iron melting zone temperature from the image. The formulas are as follows: In equations (3) and (4), c1 is the average temperature of the molten steel, T i Let n be the temperature of the i-th pixel in the molten steel. c1 C1 represents the number of cells containing molten steel, C2 represents the average temperature of the direct reduced iron melting zone, and T represents the temperature of the molten steel. j To directly restore the temperature of the j-th pixel in the molten iron zone, n c2 To directly restore the number of cells in the iron melting zone.

7. The method according to claim 1, characterized in that, The formula for calculating the current theoretical feeding rate of direct reduced iron in step S5 is as follows: Q E =[b1]·t·η E ·ε E (5) Q C =[b2]·t·△H C ·η C ·ε C (6) Q Gas =[b3]·t·△H Gas ·or Gas ·e Gas (7) In equations (5) to (9), Q E The heat provided by electrical energy, η E ε represents the efficiency of converting electrical energy into heat energy. E The efficiency of electrical energy transfer of heat to direct reduced iron; Q C The heat provided by carbon oxidation, η C It is the carbon utilization rate, ΔH C It is the heat released by the oxidation of carbon per unit mass, ε C The efficiency of heat transfer from carbon oxidation to direct reduced iron; Q Gas It is the heat provided by the combustion of combustible gas, η Gas It is the gas utilization rate, △H Gas It is the heat released by the oxidation of a unit mass of fuel gas, ε Gas The efficiency of heat transfer from combustion of the gas to direct reduced iron; t is the power supply time, b1 is the power supply of the electric arc furnace, b2 is the carbon injection rate of the electric arc furnace, b3 is the gas flow rate of the electric arc furnace; Q Steel For contact heat transfer between molten steel and direct reduced iron, c1 is the average temperature of the molten steel, c2 is the average temperature of the direct reduced iron melting zone, and R is the thermal resistance; γ steel It is the heat utilization coefficient of direct reduced iron; C p ΔT is the specific heat capacity of direct reduced iron, ΔT is the difference between the melting point T2 of direct reduced iron and the actual melting zone temperature c2, and L is the latent heat of fusion of direct reduced iron.

8. A charging system for direct reduced iron in an electric arc furnace, characterized in that, The system includes: smelting equipment, a feeding device, an image capture device, and a computer control subsystem; wherein, the smelting equipment includes a furnace body, electrodes, a gas lance, a carbon lance, a gas flow sensor, and a carbon powder quality sensor; the feeding device includes a hopper, a weighing device, a conveying device, and a feeding speed controller; the image capture device includes an industrial camera, peripheral water cooling equipment, and a data transmission interface; the computer control subsystem includes a data acquisition module, an image recognition module, a temperature comparison module, a theoretical feeding speed calculation module, and a speed control module; wherein... The data acquisition module is connected to the temperature comparison module and the theoretical charging rate calculation module. It is used to acquire the smelting plan data, raw material data and smelting condition data of the current furnace batch of the electric arc furnace according to the actual production plan, and send the raw material data to the temperature comparison module, and send the smelting plan data and smelting condition data to the theoretical charging rate calculation module. The raw material data includes the solidification temperature T1 and the melting temperature T2 of direct reduced iron. The image recognition module is connected to the data transmission interface of the image recognition device, and is also connected to the temperature comparison module and the speed control module. It is used to receive real-time images of the molten steel zone of the electric arc furnace acquired by the image capture device, and to recognize the real-time images. Based on the images, the molten steel temperature is obtained and the temperature of the iron melting zone is directly reconstructed, and then sent to the temperature comparison module and the speed control module. The temperature comparison module is connected to the theoretical feeding rate calculation module and is used to compare the relationship between the temperature of the direct reduced iron melting zone and the direct reduced iron melting temperature and solidification temperature; when the temperature of the direct reduced iron melting zone is less than or equal to T1 or the temperature of the direct reduced iron melting zone is greater than or equal to T2, the theoretical feeding rate calculation module is activated. The theoretical feeding rate calculation module is connected to the speed control module. It is used to perform energy balance calculation on the melting zone based on smelting plan data, smelting condition data, molten steel temperature and direct reduced iron melting zone temperature, to obtain the current theoretical feeding rate of direct reduced iron, and send it to the speed control module. The speed control module is connected to the feeding speed controller of the feeding device. It is used to adjust the current actual feeding speed according to the current theoretical feeding speed, adjust the current actual feeding speed to the current theoretical feeding speed, and send it to the feeding speed controller.

9. The system according to claim 8, characterized in that, The theoretical feeding rate calculation module calculates the current theoretical feeding rate of direct reduced iron using the following formula: Q E =[b1]·t·η E ·ε E (5) Q C =[b2]·t·△H C ·η C ·ε C (6) Q Gas =[b3]·t·△H Gas ·or Gas ·e G2s (7) In equations (5) to (9), Q E The heat provided by electrical energy, η E ε represents the efficiency of converting electrical energy into heat energy. E The efficiency of electrical energy transfer of heat to direct reduced iron; Q C The heat provided by carbon oxidation, η C It is the carbon utilization rate, ΔH C It is the heat released by the oxidation of carbon per unit mass, ε C The efficiency of heat transfer from carbon oxidation to direct reduced iron; Q Gas It is the heat provided by the combustion of combustible gas, η Gas It is the gas utilization rate, △H Gas It is the heat released by the oxidation of a unit mass of fuel gas, ε Gas The efficiency of heat transfer from combustion of the gas to direct reduced iron; t is the power supply time, b1 is the power supply of the electric arc furnace, b2 is the carbon injection rate of the electric arc furnace, b3 is the gas flow rate of the electric arc furnace; Q Steel For contact heat transfer between molten steel and direct reduced iron, c1 is the average temperature of the molten steel, c2 is the average temperature of the direct reduced iron melting zone, and R is the thermal resistance; γ steel It is the heat utilization coefficient of direct reduced iron; c p ΔT is the specific heat capacity of direct reduced iron, ΔT is the difference between the melting point T2 of direct reduced iron and the actual melting zone temperature c2, and L is the latent heat of fusion of direct reduced iron.

10. The system according to claim 8, characterized in that, The image capture device is located on the upper part of the eccentric bottom tapping (EBT) device in the smelting equipment, and is equipped with a high-definition lens whose range can cover the entire surface of the molten steel.

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