Method for regulating and controlling bottom blowing gas flow of electric furnace based on molten steel temperature uniformity

Abstract

The invention discloses a method for regulating and controlling the bottom blowing gas flow of an electric furnace based on molten steel temperature uniformity, and belongs to the technical field of metallurgy. A certain number of thermocouples are arranged at the bottom and on the side wall of the electric furnace, the temperature distribution state of molten steel is monitored in real time through the thermocouples, the temperature distribution uniformity of the molten steel is judged according to the temperatures fed back by the thermocouples at different positions, then the bottom blowing gas flow is dynamically adjusted, and rapid homogenization of the temperature and components of the molten steel in a molten pool is ensured. The molten steel temperature distribution uniformity is monitored in real time, the bottom blowing gas flow is dynamically adjusted according to the temperature difference, the requirements for molten steel stirring in different smelting stages can be accurately met, the bottom blowing gas flow is dynamically adjusted according to the monitored temperature difference, and a molten pool can be kept in the optimal uniform mixing state all the time. And meanwhile, the quality of molten steel is improved through accurate flow regulation and control, the smelting period is shortened, energy consumption is reduced, and the safety and stability of the smelting process are improved.

Description

Technical Field

[0001] This invention relates to the field of metallurgical technology, specifically to a method for regulating the flow rate of bottom-blown gas in an electric furnace based on the uniformity of molten steel temperature. Background Technology

[0002] In electric arc furnace steelmaking, bottom-blowing gas stirring is a crucial means to promote uniform steel composition and temperature and accelerate chemical reactions. Reasonable control of the bottom-blowing gas flow rate is essential for improving steel quality, shortening the smelting cycle, and reducing energy consumption. Several patents related to bottom-blowing flow rate control exist in the existing technology. For example, publication number CN 116356115A addresses a ladle bottom-blowing device and a method for controlling and adjusting the ladle bottom-blowing flow rate. It determines a proportional coefficient based on the actual stable argon flow rate and the maximum argon flow rate, and further adjusts the bottom-blowing flow rate using a correction coefficient. Authorization number CN 113930573 B collects, analyzes, and fits historical data on the instantaneous bottom-blowing flow rate at various task time periods and arbitrary moments in top-and-bottom blown converter production, and then combines this with feedback and correction based on the fluctuations of relevant parameters within a defined range over a recent time period. Besides the aforementioned patents, some scholars have studied the impact of bottom-blowing gas flow rate on molten steel flow and heat transfer using numerical simulation methods, finding that a reasonable bottom-blowing flow rate can effectively improve the temperature distribution and composition uniformity of molten steel. In actual production, the control of bottom blowing gas flow rate often relies on experience and lacks precise control methods, resulting in unstable steel quality and energy waste.

[0003] However, most existing methods do not fully consider adjusting the bottom blowing flow rate by the uniformity of the molten steel distribution, making it difficult to achieve precise control of the bottom blowing gas flow rate, which in turn affects the efficiency of electric arc furnace smelting and the quality of molten steel. Summary of the Invention

[0004] The purpose of this invention is to provide a method for regulating the flow rate of bottom-blown gas in an electric furnace based on the uniformity of molten steel temperature. By monitoring the temperature distribution of molten steel in real time and dynamically adjusting the flow rate of bottom-blown gas according to the temperature uniformity, the method ensures rapid homogenization of the temperature and composition of molten steel in the molten pool, improves the efficiency of electric furnace smelting, reduces energy consumption, and at the same time ensures the stability and safety of the smelting process, thereby solving the problems mentioned in the background art.

[0005] To achieve the above objectives, the present invention provides the following technical solution:

[0006] A method for regulating the flow rate of bottom-blown gas in an electric furnace based on the temperature uniformity of molten steel includes the following steps:

[0007] S1: Temperature data acquisition: Thermocouples are reasonably arranged at the bottom and side walls of the electric furnace molten pool to monitor the temperature of the molten steel in real time, and the real-time temperature difference ΔT is obtained by calculation;

[0008] S2: Set upper and lower limits for bottom blowing gas flow rate: Determine the upper limit Q of the bottom blowing gas flow rate. max and lower limit Q min ;

[0009] S3: Minimum Temperature Difference Setting and Flow Control: Define a minimum temperature difference ΔT min When the calculated real-time temperature difference ΔT is less than or equal to the minimum temperature difference ΔT min When the temperature distribution of the molten steel is relatively uniform and the mixing effect of the entire molten pool is good, it is necessary to maintain or appropriately reduce the current bottom-blowing gas flow rate Q. target When the calculated real-time temperature difference ΔT is greater than the minimum temperature difference ΔT min This indicates that the temperature distribution of the molten steel is uneven, and the mixing effect of the entire molten pool is poor. It is necessary to appropriately increase the current bottom-blowing gas flow rate Q. target .

[0010] Furthermore, in S1, temperature data from each thermocouple is continuously collected to obtain the real-time maximum temperature T of the molten steel in the molten pool. max Minimum temperature T min Furthermore, the real-time temperature difference ΔT = T is calculated. max -T min .

[0011] Furthermore, the upper limit Q of the bottom-blown gas flow rate in S2 max It is determined through experiments or experience, and its value does not exceed the limiting flow rate of the bottom blowing element; the lower limit Q of the bottom blowing gas flow rate. min The lower limit is determined by observing or experimenting to find the minimum gas flow rate that can ensure slight fluctuations in the molten pool surface.

[0012] Furthermore, the limiting flow rate of a bottom blowing element refers to the maximum gas flow rate that the bottom blowing element can withstand under safe and stable operating conditions, which can be obtained by consulting the technical parameters of the bottom blowing element or by conducting experimental tests.

[0013] Furthermore, the minimum temperature difference ΔT in S3 min The value is determined through experiments or experience based on the specifications of the electric furnace, the characteristics of the steel grade, and the requirements of the smelting process.

[0014] Furthermore, the specific method for increasing the current bottom blowing gas flow rate in S3 is as follows:

[0015] The adjusted bottom-blowing gas flow rate Q is calculated using the following formula. target Q target =min(α×(T) max -T min ) / ΔT min ×Q current Q max), where α is a correction coefficient, with a value range of 0.8-1.2. This coefficient can be adjusted according to different smelting conditions and steel characteristics.

[0016] Furthermore, the specific method for reducing the current bottom blowing gas flow rate in S3 is as follows:

[0017] The adjusted bottom-blowing gas flow rate Q is calculated using the following formula. target Q target =max(β×(T) max -T min ) / ΔT min ×Q current Q min ), where β is a correction coefficient with a value range of 0.8-1.2. This coefficient can be adjusted according to different smelting conditions and steel characteristics.

[0018] Furthermore, the bottom-blowing gas flow rate Q after adjustment in S3 target Within the upper and lower limits, i.e., Q min ≤Q target ≤Q max .

[0019] Compared with the prior art, the beneficial effects of the present invention are:

[0020] The present invention relates to a method for regulating the flow rate of bottom-blown gas in an electric furnace based on the uniformity of molten steel temperature. By monitoring the temperature distribution of molten steel in real time and dynamically adjusting the flow rate of bottom-blown gas according to the temperature uniformity, the method ensures rapid homogenization of the temperature and composition of molten steel in the molten pool, improves the efficiency of electric furnace smelting, reduces energy consumption, and at the same time ensures the stability and safety of the smelting process. Attached Figure Description

[0021] Figure 1 This is a flowchart illustrating the overall control method according to an embodiment of the present invention;

[0022] Figure 2 This is a schematic diagram of the thermocouple distribution and bottom blowing arrangement in the electric furnace molten pool in an embodiment of the present invention. Detailed Implementation

[0023] 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 some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0024] To address the technical problems of unstable treatment effect, excessive cost, severe refractory corrosion, and reduced smelting efficiency in existing electric furnace bottom blowing agitation methods, this invention provides a method for regulating the flow rate of electric furnace bottom blowing gas based on the uniformity of molten steel temperature, comprising the following steps:

[0025] S1: Temperature Data Acquisition: Thermocouples are strategically placed at the bottom and sidewalls of the electric furnace molten pool to monitor the temperature of the molten steel in real time, and the real-time temperature difference ΔT is calculated. Specifically, the temperature data of each thermocouple is continuously collected to obtain the real-time maximum temperature T of the molten steel in the pool. max Minimum temperature T min Furthermore, the real-time temperature difference ΔT = T is calculated. max -T min ;

[0026] S2: Set upper and lower limits for bottom blowing gas flow rate: Determine the upper limit Q of the bottom blowing gas flow rate. max and lower limit Q min Among them, the upper limit of the bottom-blown gas flow rate Q max It is determined through experiments or experience, and its value does not exceed the limiting flow rate of the bottom blowing element; the lower limit Q of the bottom blowing gas flow rate. min The lower limit is determined by observation or experimentation to find the minimum gas flow rate that can ensure slight fluctuations in the molten pool surface; the limit flow rate of the bottom blowing element refers to the maximum gas flow rate that the bottom blowing element can withstand under safe and stable operating conditions, which is obtained by consulting the technical parameters of the bottom blowing element or by conducting experimental tests.

[0027] S3: Minimum Temperature Difference Setting and Flow Control: Define a minimum temperature difference ΔT min ΔT min The value is determined through experiments or experience based on the specifications of the electric furnace, the characteristics of the steel grade, and the requirements of the smelting process; when the calculated real-time temperature difference ΔT is less than or equal to the minimum temperature difference ΔT... min When the temperature distribution of the molten steel is relatively uniform and the mixing effect of the entire molten pool is good, it is necessary to maintain or appropriately reduce the current bottom-blowing gas flow rate Q. target When the calculated real-time temperature difference ΔT is greater than the minimum temperature difference ΔT min This indicates that the temperature distribution of the molten steel is uneven, and the mixing effect of the entire molten pool is poor. It is necessary to appropriately increase the current bottom-blowing gas flow rate Q. target .

[0028] Specifically, the method to increase the current bottom blowing gas flow rate is as follows:

[0029] The adjusted bottom-blowing gas flow rate Q is calculated using the following formula. target Q target =min(α×(T) max -T min ) / ΔTmin ×Q current Q max ), where α is a correction coefficient, with a value range of 0.8-1.2. This coefficient can be adjusted according to different smelting conditions and steel characteristics.

[0030] The following methods can be used to reduce the current bottom blowing gas flow rate:

[0031] The adjusted bottom-blowing gas flow rate Q is calculated using the following formula. target Q target =max(β×(T) max -T min ) / ΔT min ×Q current Q min ), where β is a correction coefficient with a value range of 0.8-1.2. This coefficient can be adjusted according to different smelting conditions and steel characteristics.

[0032] In the above method, the adjusted bottom blowing gas flow rate Q target Ensure it is within the upper and lower limits, i.e., Q min ≤Q target ≤Q max .

[0033] In summary, the present invention provides a method for regulating the flow rate of bottom-blown gas in an electric furnace based on the uniformity of molten steel temperature. This method mainly involves arranging a certain number of thermocouples at the bottom and side walls of the electric furnace. The thermocouples monitor the temperature distribution of the molten steel in real time. Based on the temperature feedback from the thermocouples at different locations, the uniformity of the molten steel temperature distribution is determined, and the flow rate of bottom-blown gas is dynamically adjusted to ensure rapid homogenization of the temperature and composition of the molten steel in the molten pool.

[0034] To better understand the above technical solution, a detailed explanation will be provided below using a specific case: This case focuses on the smelting of ordinary carbon steel in a 120-ton electric furnace at a steel plant, and provides a method for controlling the flow rate of bottom-blown gas in the electric furnace based on the uniformity of molten steel temperature. Figure 1 As shown, it includes the following steps:

[0035] Step 1: Distribute three thermocouples evenly at 120° intervals at the bottom of the molten pool, with their distance from the center of the furnace being half the radius of the molten pool; distribute six thermocouples evenly along the circumference of the molten pool sidewall at 1 / 3 and 2 / 3 of the molten pool depth, as follows. Figure 2 As shown.

[0036] Step 2: Upper limit of bottom blowing gas flow rate Q max Lower limit Q min Minimum temperature difference ΔT min Setting of correction coefficients α and β:

[0037] Experiments showed that when the bottom-blown gas flow rate exceeded 80 NL / min, it had no significant further improvement effect on the mixing time in the electric furnace. Therefore, the upper limit Q of the bottom-blown gas flow rate was determined. max =80NL / min;

[0038] The lower limit Q of the bottom blowing gas flow rate was determined through actual observation. min =5NL / min, this flow rate ensures that the liquid level fluctuates slightly;

[0039] Based on numerous experiments and accumulated experience, a minimum temperature difference ΔT was determined. min =5℃;

[0040] Based on the specific working conditions of this smelting, the correction coefficients are determined to be α = 0.9 and β = 1.1.

[0041] Step 3: Collect the temperature at different locations in the electric furnace molten pool and the current bottom-blowing gas flow rate:

[0042] The maximum temperature T of the molten steel was collected by the temperature monitoring unit during the initial stage of smelting. max =1400℃, minimum temperature T min =1380℃; the initial bottom-blown gas flow rate in the smelting stage is Q current =5NL / min;

[0043] Step 4: Calculate the temperature difference ΔT, ΔT = 1400 - 1380 = 20℃;

[0044] Step 5: Bottom-blowing gas flow rate regulation and correction: Since ΔT = 20℃ > ΔT min The adjusted bottom blowing gas flow rate is calculated according to the formula:

[0045] Q target =min(0.9×(1400-1380) / 5×5,80)=18NL / min, since 18 max ,Place

[0046] Adjust the bottom blowing gas flow rate to Q target =18NL / min.

[0047] Step 6: As the smelting process proceeds, at a certain point after a period of time, the temperature monitoring unit measures the maximum temperature T. max =1510℃, minimum temperature T min =1500℃, temperature difference ΔT = 1510 - 1500 = 10℃, which is greater than the minimum temperature difference ΔT min At this point, adjust the bottom blowing gas flow rate to Q. target =min(0.9×(1510-1500) / 5×5,80)=9NL / min.

[0048] ​Step 7: Continue smelting, and after some time, the maximum temperature T is measured at a certain moment. max =1610℃, minimum temperature T min =1607℃, temperature difference ΔT = 1610 - 1607 = 3℃; since ΔT = 3℃ < ΔT min The adjusted bottom blowing gas flow rate is calculated according to the formula:

[0049] Q target =max(1.1×(1610-1607) / 5×5,5)=5NL / min, since 5 max Therefore, the bottom blowing gas flow rate is adjusted to Q. target =5NL / min.

[0050] Therefore, the method for regulating the bottom-blowing gas flow rate of an electric furnace based on the uniformity of molten steel temperature provided by this invention can accurately meet the stirring requirements of molten steel at different smelting stages by monitoring the uniformity of molten steel temperature distribution in real time and dynamically adjusting the bottom-blowing gas flow rate according to the temperature difference, thus promoting the homogenization of molten steel temperature and composition. Dynamically adjusting the bottom-blowing gas flow rate according to the monitored temperature difference ensures that the molten pool is always in an optimal mixing state. Simultaneously, precise flow rate control accelerates various chemical reactions in the molten steel, improves steel quality, shortens the smelting cycle, and reduces energy consumption. Setting upper and lower limits for the bottom-blowing gas flow rate prevents damage to the bottom-blowing elements due to excessive or insufficient flow, extends equipment lifespan, and improves the safety and stability of the smelting process. Compared with existing similar patents, this invention uniquely regulates the bottom-blowing flow rate based on the uniformity of molten steel temperature and sets scientifically reasonable flow limits, temperature difference conditions, and correction coefficients, possessing innovativeness and practical application value, and can bring significant economic benefits to steel enterprises.

[0051] It should be noted that the methods and apparatus not described in detail in the embodiments of the present invention are all prior art and will not be repeated. The above description is only a preferred embodiment of the present invention, but the protection scope of the present invention is not limited thereto. Any equivalent substitutions or changes made by those skilled in the art within the scope of the technology disclosed in the present invention, based on the technical solution and inventive concept of the present invention, should be covered within the protection scope of the present invention.​

Claims

1. A method for regulating the flow rate of bottom-blown gas in an electric furnace based on the uniformity of molten steel temperature, characterized in that, Includes the following steps: S1: Temperature data acquisition: Thermocouples are reasonably arranged at the bottom and side walls of the electric furnace molten pool to monitor the temperature of the molten steel in real time, and the real-time temperature difference ΔT is obtained by calculation; S2: Set upper and lower limits for bottom blowing gas flow rate: Determine the upper limit Q of the bottom blowing gas flow rate. max and lower limit Q min ; S3: Minimum Temperature Difference Setting and Flow Control: Define a minimum temperature difference ΔT min When the calculated real-time temperature difference ΔT is less than or equal to the minimum temperature difference ΔT min When the temperature distribution of the molten steel is relatively uniform and the mixing effect of the entire molten pool is good, it is necessary to maintain or appropriately reduce the current bottom-blowing gas flow rate Q. target When the calculated real-time temperature difference ΔT is greater than the minimum temperature difference ΔT min This indicates that the temperature distribution of the molten steel is uneven, and the mixing effect of the entire molten pool is poor. It is necessary to appropriately increase the current bottom-blowing gas flow rate Q. target .

2. The method for regulating the flow rate of bottom-blown gas in an electric furnace based on the uniformity of molten steel temperature as described in claim 1, characterized in that: In S1, temperature data from each thermocouple is continuously collected to obtain the real-time maximum temperature T of the molten steel in the molten pool. max Minimum temperature T min Furthermore, the real-time temperature difference ΔT = T is calculated. max -T min .

3. The method for regulating the flow rate of bottom-blown gas in an electric furnace based on the uniformity of molten steel temperature as described in claim 1, characterized in that: Upper limit Q of bottom blowing gas flow rate in S2 max It is determined through experiments or experience, and its value does not exceed the limiting flow rate of the bottom blowing element; the lower limit Q of the bottom blowing gas flow rate. min The lower limit is determined by observing or experimenting to find the minimum gas flow rate that can ensure slight fluctuations in the molten pool surface.

4. The method for regulating the flow rate of bottom-blown gas in an electric furnace based on the uniformity of molten steel temperature as described in claim 3, characterized in that: The limiting flow rate of a bottom blowing element refers to the maximum gas flow rate that the bottom blowing element can withstand under safe and stable operating conditions. It can be obtained by consulting the technical parameters of the bottom blowing element or by conducting experimental tests.

5. The method for regulating the flow rate of bottom-blown gas in an electric furnace based on the uniformity of molten steel temperature as described in claim 1, characterized in that: Minimum temperature difference ΔT in S3 min The value is determined through experiments or experience based on the specifications of the electric furnace, the characteristics of the steel grade, and the requirements of the smelting process.

6. The method for regulating the flow rate of bottom-blown gas in an electric furnace based on the uniformity of molten steel temperature as described in claim 1, characterized in that: The specific method for increasing the current bottom blowing gas flow rate in S3 is as follows: The adjusted bottom-blowing gas flow rate Q is calculated using the following formula. target Q target =min(α×(T) max -T min ) / ΔT min ×Q current Q max ), where α is a correction coefficient, with a value range of 0.8-1.

2. This coefficient can be adjusted according to different smelting conditions and steel characteristics.

7. The method for regulating the flow rate of bottom-blown gas in an electric furnace based on the uniformity of molten steel temperature as described in claim 1, characterized in that: The specific methods for reducing the current bottom blowing gas flow rate in S3 are as follows: The adjusted bottom-blowing gas flow rate Q is calculated using the following formula. target Q target =max(β×(T) max -T min ) / ΔT min ×Q current Q min ), where β is a correction coefficient with a value range of 0.8-1.

2. This coefficient can be adjusted according to different smelting conditions and steel characteristics.

8. The method for regulating the flow rate of bottom-blown gas in an electric furnace based on the uniformity of molten steel temperature as described in claim 1, characterized in that: The bottom blowing gas flow rate Q after adjustment in S3 target Within the upper and lower limits, i.e., Q min ≤Q target ≤Q max .

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