A high-efficiency power supply method and system for electric arc furnace smelting process

Abstract

The present invention discloses an efficient power supply method and system for an electric arc furnace smelting process, which belongs to the technical field of intelligent power consumption in smelting process. Specifically, the noise intensity model of the electric arc furnace in different smelting stages is established, and the noise intensity of the drilling stage is obtained as N. 穿井 After the drilling is completed, the molten pool stage begins to form, and the noise intensity of the molten pool stage is N 熔化 After the scrap steel is melted, it enters the heating stage. The noise intensity in the heating stage is N 升温 ; Calculate the current average noise intensity N during the smelting process 平均 , using the latest noise intensity average N 平均 With N 穿井、 N 熔化 and N 升温 Compare, according to N 平均 With N 穿井、 N 熔化 and N 升温 The invention reduces smelting power consumption and improves energy utilization rate of electric arc furnace smelting process.

Description

Technical Field

[0001] The present invention relates to a high-efficiency power supply method and system for an electric arc furnace smelting process, belonging to the technical field of smart electricity use in smelting processes. Background Art

[0002] The electric arc furnace steelmaking process uses scrap steel as raw material. Compared to the long blast furnace-converter process, the shortened process reduces CO2 emissions by 75%. In electric furnace smelting, arc radiation generated during the electric arc furnace smelting process is the primary energy source for melting scrap steel. Therefore, a reasonable power supply system is crucial for reducing smelting power consumption and shortening power-on time.

[0003] The main parameters that change when power is applied are arc voltage and arc current. Arc voltage and current affect the active power input into the furnace and the arc length. Therefore, the selection of arc voltage and current when power is applied will have a significant impact on the power-on time and smelting power consumption.

[0004] Patent CN109136462A introduces a method for powering an electric furnace, in which the voltage and current levels are changed mainly according to the power-on time, thereby improving energy utilization and reducing the power consumption of the electric arc furnace during the smelting process. Patent CN115737495A provides a power supply process for a large AC electric arc furnace, in which different active power and power factors are designed at different stages of electric furnace smelting, thereby adjusting the smelting efficiency and production costs to achieve the best economic benefits of the electric arc furnace. Patent CN10132967B provides an electric arc furnace energy segment input control method, in which electrical energy and other energy are input into each energy segment of the electric arc furnace smelting through theoretical calculations to achieve optimal configuration of electrical energy and chemical energy. When optimizing the power supply of the electric arc furnace using the above methods, it is necessary to judge the stage of melting of scrap steel in the furnace during smelting of the electric arc furnace, and optimize the power supply system according to the different stages of melting of scrap steel.

[0005] Current methods for optimizing electric arc furnace power supply systems primarily use power-on time or energy balance to determine the scrap melting stage, thereby setting the voltage and current levels. However, due to the wide variety of scrap types used in electric arc furnaces, theoretical calculations are difficult to determine the scrap melting stage in actual production. This is often left to operators to determine based on their personal experience, leading to inconsistent criteria for determining the scrap melting stage and making it difficult to optimize the power supply system.

[0006] In response to the current problems, this patent provides an efficient power supply method and system for the electric arc furnace smelting process. This method dynamically adjusts the power supply system in real time based on the changes in noise signals at different stages of the electric arc furnace smelting process, thereby achieving efficient input of electrical energy during the arc smelting process, reducing power-on time, and reducing smelting power consumption. Summary of the Invention

[0007] In order to solve the above problems, the present invention discloses a high-efficiency power supply method and system for an electric arc furnace smelting process, and its specific technical solutions are as follows:

[0008] A high-efficiency power supply method for an electric arc furnace smelting process comprises the following steps:

[0009] Step 1: Establish the noise intensity model of different smelting stages of the electric arc furnace, and obtain the noise intensity of the drilling stage as N 穿井 After the drilling is completed, the molten pool stage begins to form, and the noise intensity of the molten pool stage is N 熔化 After the scrap steel is melted, it enters the heating stage. The noise intensity in the heating stage is N 升温 ;

[0010] Step 2: During the smelting process, the noise intensity of the arc furnace is collected in real time at an interval of X seconds. The duration of Y seconds is used as a cycle unit. The starting point of the collection point of the cycle unit is located in a cycle unit upstream of the adjacent cycle unit. The average noise intensity N in each cycle unit is calculated. 平均 , using the average noise intensity N of the latest cycle unit 平均 With N 穿井、 N 熔化 and N 升温 Compare, according to N 平均 With N 穿井、 N 熔化 and N 升温 The size of the resistor can be adjusted to make appropriate voltage and current adjustments.

[0011] Furthermore, the starting point of the periodic unit is the second point in the previous periodic unit.

[0012] Furthermore, when it is determined that the next stage has been entered, the real-time data collection at this time does not need to take values ​​from the previous cycle unit, and the moment of entering the next stage is used as the starting point of the cycle unit.

[0013] Furthermore, the specific method for establishing the noise intensity model of different smelting stages of the electric arc furnace is as follows: the noise data of the first 10 furnaces with the same molten iron ratio are selected, and the noise intensity of the 30s interval is averaged according to the power-on time, N i-1 、N i and N i+1 are the noise intensity values ​​at time i-1, time i and time i+1 respectively. If N i With N i-1 The noise intensity difference is greater than 6dB, and N i+1 With N i If the noise intensity difference is less than 3dB, the scrap melting stage changes;

[0014] The average noise intensity at all times in each stage is calculated to obtain the noise control intensity N of the three stages of drilling, melting and heating. 穿井 、N 熔化 and N 升温 .

[0015] Furthermore, in the arc starting stage, the voltage gear adopts 8 gears and the current gear adopts 6 gears; when the real-time noise intensity N≥N 穿井 When the voltage gear is 12 gears and the current gear is 5 gears; when the real-time noise intensity N 穿井 >N≥N 熔化 When the voltage gear is 15 gears and the current gear is 5 gears; when the real-time noise intensity N 熔化 >N≥N 升温 When the voltage gear is 13 gears, the current gear is 9 gears;

[0016] During the arc starting period, the 8th gear voltage is 698V and the 6th gear current is 44KA; during the well penetration period, the 12th gear voltage is 815V and the 5th gear current is 43KA; during the melting period, the 15th gear voltage is 843V and the 5th gear current is 42KA; during the heating period, the 13th gear voltage is 900V and the 9th gear current is 51KA.

[0017] Furthermore, the rated power of the transformer used in the electric arc furnace is 65MW, and the scrap steel ratio of the electric arc furnace is 60% to 70%.

[0018] Furthermore, the voltage and current levels at each stage of the electric arc furnace smelting process are automatically adjusted by a first-level program.

[0019] An electric arc furnace high-efficiency power supply system for implementing a high-efficiency power supply method for an electric arc furnace smelting process, comprising: a memory, a processor, and a controller, wherein the memory is used to receive and store collected noise intensity information, the memory storing a computer program, the processor implementing the high-efficiency power supply method for an electric arc furnace smelting process, and processing the noise intensity information in the memory, wherein the processor executes the computer program;

[0020] When establishing the noise intensity model for different smelting stages of an electric arc furnace, first set the current molten iron ratio, then record M groups of data for the arc starting period, well penetration period, melting period, and heating period in sequence, calculate the average of the simultaneous values ​​between each group, and obtain the noise control intensity range for each stage.

[0021] By changing different molten iron ratios and repeating the above process, we can obtain the average noise intensity in the time period corresponding to different molten iron ratios.

[0022] storing the molten iron ratio and the corresponding noise control intensity range of each stage in a memory;

[0023] During the smelting process, the memory stores the real-time noise intensity, the average noise intensity within the time period and the real-time stage information.

[0024] The processor calculates an average noise intensity within a time period, and compares the average noise intensity within the time period with the average noise intensity within the time period stored in the memory, and feeds the comparison result back to the memory and the controller;

[0025] The controller is used to adjust the current and voltage in real time after receiving the comparison result fed back by the processor.

[0026] Furthermore, it also includes: an industrial microphone, which is facing the front of the furnace door and suspended above the front of the furnace door for collecting sound signals.

[0027] Furthermore, the memory is also used to store the noise audio information of the historical furnaces.

[0028] The beneficial effects of the present invention are:

[0029] The present invention provides a new perspective on the use of electricity in electric arc furnace smelting. It proposes using noise signals to dynamically identify the smelting stage in real time and contactlessly, and through use verification, the smelting effect is stable.

[0030] The present invention can dynamically adjust the power supply system in real time according to the changes in noise signals at different stages of the electric arc furnace smelting process, thereby achieving efficient input of electric energy during the electric arc furnace smelting process, reducing power-on time, reducing smelting power consumption, and improving energy utilization of the electric arc furnace smelting process.

[0031] Compared with traditional methods, the present invention can dynamically adjust the power supply system according to the actual conditions of the scrap steel entering the furnace, avoiding the deviation problem existing in theoretical calculations, and has significant effects in shortening the power-on time and reducing smelting power consumption. BRIEF DESCRIPTION OF THE DRAWINGS

[0032] Figure 1 It is a schematic flow chart of the present invention,

[0033] Figure 2 is the average noise intensity N during the smelting process of the present invention 平均 Calculation cycle diagram. DETAILED DESCRIPTION

[0034] The present invention will be further described below in conjunction with the accompanying drawings and specific embodiments. It should be understood that the following specific embodiments are only used to illustrate the present invention and are not intended to limit the scope of the present invention.

[0035] The method for high-efficiency power supply in the electric arc furnace smelting process includes the following steps: Figure 1

[0036] (1) Establish the noise intensity model of different smelting stages of the electric arc furnace, and obtain the noise intensity of the drilling stage as N 穿井 After the drilling is completed, the molten pool stage begins to form, and the noise intensity of the molten pool stage is N 熔化 After the scrap steel is melted, it enters the heating stage. The noise intensity in the heating stage is N 升温 ;

[0037] (2) During the smelting process, the noise intensity of the arc furnace is collected in real time at a time interval of X seconds. The duration of Y seconds is used as a cycle unit. The starting point of the collection point of the cycle unit is located in a cycle unit upstream of its adjacent time. The average noise intensity N in each cycle unit is calculated. 平均 , using the average noise intensity N of the latest cycle unit 平均 With N 穿井、 N 熔化 and N 升温 Compare, according to N 平均 With N 穿井、 N 熔化 and N 升温 The voltage and current can be adjusted accordingly based on the size of the scrap. Voltage and current adjustments are based on the melting state of the scrap in the furnace. Currently, the parameter that can reflect this melting state is noise level. Loud noise indicates incomplete melting of the scrap in the furnace. The more molten iron fed into the furnace, the faster the scrap melts, and the faster the noise decreases. Therefore, voltage and current can be adjusted based on the noise level. During the drilling phase, when noise is high, low voltage and high current arc operation is used to improve arc stability. During the melting phase, when a molten pool is formed, noise is reduced, and high voltage, low current, and long arc operation are used to provide active power. During the heating phase, noise is minimized, and low voltage and high current are used to improve energy utilization.

[0038] In order to increase the density of collected data and the accuracy of the data, the starting point of the cycle unit is the second collection point in the previous cycle unit. When it is determined to enter the next stage, the real-time data collection at this time does not need to take the value from the previous cycle unit. The moment of entering the next stage is used as the starting point of the cycle unit. For details, please refer to the attached Figure 2 In the figure, the time interval is X seconds, which is 5 seconds, and the duration is Y seconds, which is 30 seconds, as the period unit. Only the first value point is staggered between period units.

[0039] The specific method for establishing the noise intensity model of different smelting stages of electric arc furnace is as follows: select the first 10 furnaces with the same molten iron ratio. Here, the molten iron ratio is a variable. Each time the data is selected, the furnaces with the same molten iron ratio should be selected. The noise data of the smelting furnaces are averaged at 30s intervals according to the power-on time, and N i-1 、N i and N i+1 are the noise intensity values ​​at time i-1, time i and time i+1 respectively. If Ni With N i-1 The noise intensity difference is greater than 6dB, and N i+1 With N i If the noise intensity difference is less than 3dB, the scrap steel melting stage has changed. Count the noise intensity N at all times in each stage. i The average value of the noise control intensity N in the three stages of drilling, melting and heating is obtained. 穿井 、N 熔化 and N 升温 .

[0040] The following describes the corresponding power supply measures for each stage: In the arc starting stage, the voltage gear adopts 8 gears and the current gear adopts 6 gears. The voltage of gear 8 is 698V and the current of gear 6 is 44KA. When the real-time noise intensity N≥N 穿井 During the drilling period, the voltage level is 12 and the current level is 5. The voltage level 12 is 815V and the current level 5 is 43KA. 穿井 >N≥N 熔化 During the melting period, the voltage level is 15 and the current level is 5. The voltage level 15 is 843V and the current level 5 is 42KA. 熔化 >N≥N 升温 During the heating period, the voltage gear adopts gear 13 and the current gear adopts gear 9. The voltage of gear 13 is 900V and the current of gear 9 is 51KA.

[0041] During the drilling period, the noise is high, and low voltage and high current arc operation is used to improve arc stability. During the melting period, the molten pool is formed and the noise is reduced. High voltage, low current and long arc operation are used to provide active power and quickly melt the scrap steel. During the heating period, the noise is minimal, low voltage and high current are used to improve energy utilization.

[0042] The transformer used in an electric arc furnace has a rated power of 65MW, and the scrap ratio of the furnace is 60% to 70%. In actual production, there is no direct relationship between transformer power and scrap ratio. The rated power of the transformer generally depends on the nominal capacity of the furnace.

[0043] The voltage and current levels at each stage of the arc furnace smelting process are automatically adjusted by a first-level program. This refers to a first-level automated PLC control program. The control principle is that voltage and current level signals are sent to the PLC program, which then controls the voltage and current switches for adjustment.

[0044] An electric arc furnace high-efficiency power supply system for implementing a high-efficiency power supply method for an electric arc furnace smelting process includes: a memory, a processor, and a controller. The memory is configured to receive and store collected noise intensity information. The memory stores a computer program that compares noise intensity signals at different times, identifies different smelting stages based on the comparison results, and calculates the average noise level for each smelting stage. The processor is configured to process the noise intensity information in the memory when executing the computer program.

[0045] When establishing the noise intensity model for different smelting stages of an electric arc furnace, first set the current iron-to-liquid ratio, then record M groups of data for the arc starting period, well penetration period, melting period, and heating period in sequence, and calculate the average of the simultaneous times between each group to obtain the noise control intensity range for each stage.

[0046] By changing different molten iron ratios and repeating the above process, the average noise intensity in the time period corresponding to the different molten iron ratios is obtained.

[0047] The molten iron ratio and the corresponding noise control intensity range of each stage are stored in the memory.

[0048] During the smelting process, the memory stores the real-time noise intensity, the average noise intensity within a period of time, and the real-time stage information.

[0049] The processor calculates the average noise intensity within the time period, and compares the average noise intensity within the time period with the average noise intensity within the time period stored in the memory, and feeds the comparison result back to the memory and the controller. The memory is also used to store the noise audio information of the historical furnace.

[0050] The controller is used to adjust the current and voltage in real time after receiving the comparison result fed back by the processor.

[0051] An industrial microphone is also included for collecting sound signals. The industrial microphone faces the front of the furnace door and is suspended directly above the furnace door. Specifically, the industrial microphone is installed on the wall of the main control room in front of the furnace door, 10-12 meters away from the furnace door and 1.0-1.2 meters above the ground.

[0052] When modeling, by replacing one variable and keeping other variables unchanged, we can complete the corresponding N in more situations. 穿井、 N 熔化 and N 升温 , build a rich database and achieve data matching in more situations. Example

[0053] Example 1:

[0054] The electric arc furnace is equipped with a 65MW transformer, with a scrap steel ratio of 65%. Scrap steel is added to the furnace at one time through a bag. The electric furnace noise collection device is installed on the wall of the operating room opposite the furnace door, with a distance of 10m between the two. The sound collection frequency is 44100HZ. The collected sound signal is transmitted to the first-level computer in the main control room. After program processing, the average sound intensity signal at intervals of 30s is obtained. Based on the molten iron ratio of the furnace, the first 10 smelting heats with the same molten iron ratio are selected, and the historical noise intensity signals stored in the computer are processed to obtain the average noise intensity N of the electric furnace smelting well drilling stage. 穿井 The average noise intensity during the melting phase is 80dB. 熔化 The average noise intensity during the heating stage is 75dB. 升温 The noise intensity is 70dB, and the above noise intensity value is used as the judgment signal of the smelting stage of this furnace. After the start of this furnace smelting, 8 voltage gears and 6 current gears are used in the arc starting stage. After 30s of power-on time, the monitored sound intensity reaches 82dB, and the electric arc furnace smelting reaches the well-penetrating stage. At this time, the voltage gear is changed to 12 gears and the current gear is changed to 5 gears. After 120s of power-on time, the monitored sound intensity is reduced to 76dB, and the well-penetrating stage of the electric arc furnace smelting ends and reaches the melting stage. At this time, the voltage gear is changed to 15 gears and the current gear is changed to 5 gears. After 600s of power-on time, the monitored sound intensity average value is reduced to 71dB, and the melting stage of the electric arc furnace smelting ends and reaches the molten pool heating stage. At this time, the voltage gear is changed to 13 gears and the current gear is changed to 9 gears.

[0055] Example 2:

[0056] The electric arc furnace smelting is equipped with a 65MW transformer, with a scrap steel ratio of 70%. The scrap steel is added to the furnace at one time through a bag. The electric furnace noise collection device is installed on the wall of the operating room opposite the furnace door, with a distance of 10m between the two. The sound collection frequency is 44100HZ. The collected sound signal is transmitted to the first-level computer in the main control room. After program processing, the average sound intensity signal at intervals of 30s is obtained. Based on the molten iron ratio of the furnace, the first 10 smelting heats with the same molten iron ratio are selected, and the historical noise intensity signals stored in the computer are processed to obtain the average noise intensity N of the electric furnace smelting well drilling stage. 穿井 The average noise intensity during the melting phase is 82dB. 熔化 The average noise intensity during the heating stage is 75dB. 升温The noise intensity value is 68dB, and the above noise intensity value is used as the judgment signal of the smelting stage of this furnace. After the start of this furnace smelting, 8 voltage gears and 6 current gears are used in the arc starting stage. After 30s of power-on time, the monitored sound intensity reaches 83dB, and the electric arc furnace smelting reaches the well-penetrating stage. At this time, the voltage gear is changed to 12 and the current gear is changed to 5. After 150s of power-on time, the monitored sound intensity is reduced to 75dB, and the well-penetrating stage of the electric arc furnace smelting ends and reaches the melting stage. At this time, the voltage gear is changed to 15 and the current gear is changed to 5. After 690s of power-on time, the monitored average sound intensity is reduced to 69dB, and the melting stage of the electric arc furnace smelting ends and reaches the molten pool heating stage. At this time, the voltage gear is changed to 13 and the current gear is changed to 9.

[0057] The method of the present invention has been applied in practical applications, and after data comparison, it was found that the database established by the method of the present invention and the corresponding electricity consumption strategy consume less electricity than smelting raw materials and smelting results under the same conditions.

[0058] The technical means disclosed in the solution of the present invention are not limited to the technical means disclosed in the above technical means, but also include technical solutions composed of any combination of the above technical features.

[0059] With the above-described preferred embodiments of the present invention as a guide, and with reference to the above description, relevant personnel are fully capable of making various changes and modifications without departing from the technical scope of this invention. The technical scope of this invention is not limited to the contents of the specification and must be determined according to the scope of the claims.

Claims

1. A high-efficiency power supply method for an electric arc furnace smelting process, characterized in that: The following steps are involved: Step 1: Establish the noise intensity model of different smelting stages of the electric arc furnace, and obtain the noise intensity of the drilling stage as N 穿井 After the drilling is completed, the molten pool stage begins to form, and the noise intensity of the molten pool stage is N 熔化 After the scrap steel is melted, it enters the heating stage. The noise intensity in the heating stage is N 升温 ; The average noise intensity of all moments in each stage is calculated to obtain the noise intensity N of the three stages of drilling, melting and heating. 穿井 、N 熔化 and N 升温 ; When establishing the noise intensity model for different smelting stages of an electric arc furnace, first set the current molten iron ratio, then record M groups of data for the arc starting period, well penetration period, melting period, and heating period in sequence, calculate the average of the simultaneous values ​​between each group, and obtain the noise control intensity range for each stage. By changing different molten iron ratios and repeating the above process, the average noise intensity in the time period corresponding to the different molten iron ratios is obtained; Step 2: During the smelting process, the noise intensity of the arc furnace is collected in real time at an interval of X seconds. The duration of Y seconds is used as a cycle unit. The starting point of the collection point of the cycle unit is located in a cycle unit upstream of the adjacent cycle unit. The average noise intensity in each cycle unit is calculated and the average noise intensity of the latest cycle unit is used as the value N. 平均 With N 穿井、 N 熔化 and N 升温 Compare, according to N 平均 With N 穿井、 N 熔化 and N 升温 The size of the voltage and current can be adjusted accordingly. The specific method for establishing the noise intensity model of different smelting stages of the electric arc furnace is as follows: selecting the noise data of the first 10 furnaces with the same molten iron ratio, averaging the noise intensity at intervals of 30 seconds according to the power-on time, and calculating N i-1 、N i and N i+1 are the noise intensity values ​​at time i-1, time i and time i+1 respectively. If N i With N i-1 The noise intensity difference is greater than 6dB, and N i+1 With N i If the noise intensity difference is less than 3dB, the scrap melting stage will change; The voltage range in the arc starting stage is 8, and the current range is 6. When the average noise intensity N in the real-time cycle unit is 平均 ≥N 穿井 When the voltage gear is 12 gears and the current gear is 5 gears; when the average noise intensity N in the real-time cycle unit is 穿井 >N 平均 ≥N 熔化 When the voltage gear is 15 gears and the current gear is 5 gears; when the average noise intensity N in the real-time cycle unit 熔化 >N 平均 ≥N 升温 When the voltage gear is 13 gears, the current gear is 9 gears; The industrial microphone faces the front of the furnace door and is suspended above the front of the furnace door to collect sound signals.

2. The high-efficiency power supply method for electric arc furnace smelting process according to claim 1, characterized in that: The starting point of the periodic unit is the second point in the previous periodic unit.

3. The high-efficiency power supply method for electric arc furnace smelting process according to claim 1, characterized in that: When it is determined that the next stage has been entered, the real-time data collection at this time does not need to take values ​​from the previous cycle unit. The moment of entering the next stage is used as the starting point of the cycle unit.

4. The high-efficiency power supply method for electric arc furnace smelting process according to claim 1, characterized in that: During the arc starting period, the 8th gear voltage is 698V and the 6th gear current is 44KA; during the well penetration period, the 12th gear voltage is 815V and the 5th gear current is 43KA; during the melting period, the 15th gear voltage is 843V and the 5th gear current is 42KA; during the heating period, the 13th gear voltage is 900V and the 9th gear current is 51KA.

5. The high-efficiency power supply method for electric arc furnace smelting process according to claim 1, characterized in that: The transformer used in the electric arc furnace has a rated power of 65MW, and the scrap steel ratio of the electric arc furnace is 60% to 70%.

6. The high-efficiency power supply method for electric arc furnace smelting process according to claim 1, characterized in that: The voltage and current levels at each stage of the electric arc furnace smelting process are automatically adjusted by a first-level program.

7. An electric arc furnace high-efficiency power supply system for implementing the method according to any one of claims 1 to 6, characterized in that: include: A memory, a processor, and a controller, wherein the memory is used to receive and store the collected noise intensity information, the memory stores a computer program, the processor is used to process the noise intensity information in the memory according to the method according to claim 1, and the processor processes the noise intensity information when executing the computer program; storing the molten iron ratio and the corresponding noise control intensity range of each stage in a memory; During the smelting process, the memory stores the real-time noise intensity, the average noise intensity within the time period and the real-time stage information. The processor calculates an average noise intensity within a time period, and compares the average noise intensity within the time period with the average noise intensity within the time period stored in the memory, and feeds the comparison result back to the memory and the controller; The controller is used to adjust the current and voltage in real time after receiving the comparison result fed back by the processor.

8. The high-efficiency power supply system for an electric arc furnace according to claim 7, characterized in that: The memory is also used to store noise audio information of historical furnaces.

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