A method for evaluating the activity of a blast furnace hearth

Abstract

A method for evaluating the activity of a blast furnace hearth is disclosed, relating to the field of automated monitoring technology for blast furnace ironmaking. The beneficial effects of this invention are as follows: This invention constructs a multi-parameter quantitative evaluation model by integrating eight dimensions, including physical thermal index, sidewall temperature change, tapping index, blast pressure stability, lower temperature stability, permeability index, FeO content, and lower valve box temperature. Combined with a dynamic weight allocation mechanism and a visual monitoring platform, it achieves real-time online monitoring and accurate evaluation of blast furnace hearth activity. The scoring update frequency can reach 30 times / hour, the prediction accuracy is improved to over 90%, the early warning time is advanced to 6 hours before anomalies occur, the accuracy of control measures is improved by 35%, and the number of production reductions due to furnace condition fluctuations is reduced by 42%. It effectively overcomes the shortcomings of traditional methods, such as strong lag, single indicators, and reliance on manual experience. It has good universality and long-term optimization capabilities, providing reliable technical support for stable and smooth blast furnace operation and low-consumption, high-efficiency production.

Description

Technical Field

[0001] This invention relates to the field of automated monitoring technology for blast furnace ironmaking, and specifically to a method for evaluating the activity of the blast furnace hearth. Background Technology

[0002] Blast furnace ironmaking is the core process of modern steel production, and the hearth, as an important area in blast furnace smelting, directly affects the smooth operation, technical and economic indicators, and service life of the blast furnace. Hearth activity refers to the degree of adequacy of gas flow distribution, heat transfer, and material exchange within the hearth. An active hearth is the foundation for stable and smooth blast furnace operation and achieving low-consumption and high-efficiency production.

[0003] Currently, the main methods for evaluating the activity of blast furnace hearths fall into the following categories: 1. Temperature characterization method: This method indirectly characterizes the activity of the hearth by monitoring the ratio of the temperature at the center of the furnace bottom to the temperature on the sidewall of the hearth. This method has a significant time lag; by the time a significant temperature change is detected, abnormal hearth activity has often already occurred, making timely warning and control impossible.

[0004] 2. Blowering kinetic energy method: This method evaluates the characteristics of the vortex zone by calculating the blowing kinetic energy at the vent. However, there is a mismatch between the blowing kinetic energy and the shape characteristics of the vortex zone; the same blowing kinetic energy may correspond to different vortex zone shapes, and this method does not consider the uniformity of the vent's circumference.

[0005] 3. Hearth Sampling Method: This method assesses the hearth condition by analyzing coke particle size and slag-to-iron retention ratio during blast furnace shutdowns. While direct, this method requires blast furnace shutdowns, is complex to operate, and cannot achieve online real-time evaluation.

[0006] Traditional methods share common drawbacks, including the use of single evaluation indicators, susceptibility to interference from operating parameters, inability to reflect hearth state fluctuations in real time, and lack of universality for blast furnaces of different volumes and smelting conditions. In recent years, with the increasing size of blast furnaces and the diversification of raw material conditions, there is an urgent need for a hearth activity evaluation method that can adapt to various operating conditions, is accurate, reliable, and has strong real-time performance.

[0007] Meanwhile, existing patents, such as CN112111617B, evaluate activity level by the area ratio of the tuyeres' swirl zone and the permeability index, but do not address the correlation between the state of dead material columns and the composition of molten iron; CN115481350A uses tuyeres coke particle size analysis, but requires sampling during tuyeres shutdown and cannot be applied in real time; CN114703334A designs a multi-parameter scoring system for vanadium-titanium ore smelting, but does not clearly define the dynamic weighting mechanism. Therefore, an evaluation method that can integrate real-time data, dynamic weights, and is applicable to various smelting scenarios is needed. Summary of the Invention

[0008] The purpose of this invention is to provide a method for evaluating the activity of a blast furnace hearth, addressing the shortcomings and defects of existing technologies.

[0009] To achieve the above objectives, the present invention adopts the following technical solution: a method for evaluating the activity of a blast furnace hearth, comprising the following steps: collecting blast furnace production data, including the physical heat temperature of molten iron, silicon content of molten iron, hearth sidewall temperature, furnace bottom center temperature, tapping rate, blast pressure, lower furnace body temperature, permeability index, FeO content in slag, and lower valve box temperature; based on the collected blast furnace production data, calculating the following evaluation indicators in several dimensions: physical heat index: the correlation coefficient between the physical heat of molten iron and silicon content; sidewall temperature change: the ratio of the furnace bottom center temperature to the average hearth sidewall temperature; tapping index: the change in hearth tapping rate measured by the amount of iron tapped each time; blast pressure stability: the standard deviation of blast pressure fluctuation; lower furnace body temperature stability: the lower furnace body temperature stability index; permeability index: the permeability index deviation rate; FeO content: the FeO content in slag; lower valve box temperature: the trend of lower valve box temperature change; determining the weight of each indicator through the analytic hierarchy process (AHP), constructing a comprehensive scoring model for hearth activity, with a score of 0-100.

[0010] Furthermore, the formula for the physical thermal index is: Where tp is the physical heat of molten iron, in °C; Si is the silicon content of molten iron, in %; the trend of this index can reflect the trend of physical heat in a timely manner. The parameter limit is set to 1.4, 1.6, 1.9, 2.1, 2.4, 2.7 according to the physical heat index value, and the corresponding scores are 50, 60, 70, 80, 90, 100, and this item accounts for 35% of the weight.

[0011] Furthermore, the sidewall temperature change is the ratio of the average temperature of the furnace bottom center to the average temperature of the furnace hearth sidewall; the parameter limit is set according to the temperature ratio as 2.6, 2.63, 2.67, 2.71, 2.75, 2.78, with corresponding scores of 50, 60, 70, 80, 90, 100, and this item has a weight of 25%.

[0012] Furthermore, the method for calculating the iron tapping index is as follows: Where Y is the daily iron production of the blast furnace, in tons; D is the number of times the furnace is blasted per day, in times; the parameter limits are set to 3.7, 3.9, 4.2, 4.6, 5, and 5.5 based on the iron tapping index value, with corresponding scores of 50, 60, 70, 80, 90, and 100, and this item accounts for 15% of the weight.

[0013] Furthermore, the wind pressure stability is calculated by taking an average value every 10 minutes to calculate the wind pressure deviation value for one day. When the value is negative, the absolute value is taken. The parameter limit is set to 5, 6, 7, 8, 9, 10 according to the wind pressure stability value, and the corresponding scores are 100, 90, 80, 70, 60, 50, and this item accounts for 5% of the weight.

[0014] Furthermore, the lower temperature stability refers to the temperature stability of the lower part of the furnace body: an average value is taken every 10 minutes to calculate the temperature deviation value for one day; the parameter limit is set to 5, 6, 7, 8, 9, 10, 11, 12 according to the value of the lower temperature stability of the furnace body, and the corresponding scores are 100, 90, 80, 70, 60, 50, 40, 30, and this item accounts for 5% of the weight.

[0015] Furthermore, the breathability index is the breathability index deviation rate, and the breathability index... The permeability index reflects the air permeability of the blast furnace bed. Here, V is the amount of gas generated in the blast furnace belly area; Q is the gas flow rate, which is the amount of gas passing through a certain cross section of the blast furnace per unit time; and h is the burden thickness, which is the height of the burden in the blast furnace. The parameter limits are set to 0.86, 0.89, 0.91, 0.94, 0.97, and 1 based on the permeability index value, with corresponding scores of 50, 60, 70, 80, 90, and 100, and this item accounts for 5% of the weight.

[0016] Furthermore, the FeO content is the ratio of the FeO content in the slag to the benchmark value (0.35%); the parameter limit is set to 1, 1.14, 1.29, 1.43, 1.57, and 1.71 according to the FeO content value, and the corresponding scores are 100, 90, 80, 70, 60, and 50, and this item accounts for 5% of the weight.

[0017] Furthermore, the lower valve box temperature is the trend of lower valve box temperature change. The parameter limit is set to 100, 110, 120, 130, 140, and 150 according to the lower valve box temperature value, with corresponding scores of 25, 40, 55, 70, 85, and 100, and this item accounts for 5% of the weight.

[0018] Furthermore, a dynamic weight allocation mechanism is introduced, and the comprehensive score calculation formula is as follows: ,in, The result is the weighted sum of the scores of each indicator. ,Right now ,in: The weight percentages for each indicator are as follows: physical thermal index, sidewall temperature change, iron tapping index, wind pressure stability, lower temperature stability, air permeability index, FeO content, and lower valve box temperature, with x1+x2+x3+x4+x5+x6+x7+x8=100%; .

[0019] After adopting the above technical solution, the beneficial effects of the present invention are at least as follows: 1. This invention is based on conventional blast furnace production data (such as molten iron temperature, air pressure, slag composition, etc.) for calculation, and the scoring update frequency can reach 30 times / hour, which is much higher than the traditional method (4~8 hours), and can realize continuous online monitoring of hearth activity.

[0020] 2. By using multi-parameter fusion and dynamic weighting mechanisms, combined with correlation analysis and machine learning correction, the model's prediction accuracy for the inactive state of the hearth has been improved to over 90%, effectively overcoming the subjectivity and lag of single indicators or human experience judgment.

[0021] 3. The eight evaluation indicators selected in this invention cover thermodynamics, fluid dynamics, and chemical reaction characteristics, and are applicable to blast furnaces of different volumes and various smelting scenarios, demonstrating good universality.

[0022] 4. By combining a visual monitoring platform with a dynamic weight adjustment mechanism, the system can provide early warnings before the hearth activity decreases. Examples show that after applying this invention, early warnings of hearth inactivity can be issued up to 6 hours before the anomaly occurs, and the accuracy of control measures is improved by 35%.

[0023] 5. Through timely early warning and precise control, the number of production cuts caused by furnace condition fluctuations is effectively reduced. In the example, the number of production cuts decreased by 42% after applying this invention, improving the stability and economy of blast furnace production.

[0024] 6. This invention supports historical data accumulation and algorithm trend prediction. After accumulating 3 months of data, it can provide a risk warning of activity decline 24 hours in advance, providing forward-looking guidance for blast furnace operation. Attached Figure Description

[0025] To more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the 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.

[0026] Figure 1 This is a schematic diagram of the lower temperature stability and lower valve box temperature in this invention.

[0027] Figure 2 This is a schematic diagram of wind pressure stability and FeO content in this invention.

[0028] Figure 3 This is a schematic diagram of the physical thermal index and the iron tapping index in this invention.

[0029] Figure 4 This is a schematic diagram showing the relationship between the air permeability index and the sidewall temperature in this invention. Detailed Implementation

[0030] See Figures 1-4 As shown, the technical solution adopted in this specific embodiment is: At 1950m 3 Taking a blast furnace as an example, the specific implementation steps are as follows: 1. Data Acquisition: Real-time data such as molten iron temperature, air pressure, and slag composition are acquired from the existing sensor system and stored in the database. Blast furnace production data is collected, including physical thermal index, sidewall temperature change, tapping index, air pressure stability, lower temperature stability, permeability index, FeO content, FeO content in slag, and lower valve box temperature.

[0031] 2. Based on the data, calculate the evaluation indicators for the following eight dimensions and generate curves.

[0032] 1) Calculate the indicators and obtain the scores for each indicator: 2) Calculation of Indicators: Calculate the physical thermal index, sidewall temperature change, iron tapping index, air pressure stability, lower temperature stability, permeability index, FeO content, and lower valve box temperature. Indicator Scores: Calculate the scores for the physical thermal index, sidewall temperature change, iron tapping index, air pressure stability, lower temperature stability, permeability index, FeO content, and lower valve box temperature.

[0033] 3) Weight allocation: (1) Determine the correspondence between the physical heat of molten iron and its silicon content: expressed using the physical heat index calculation method on a furnace basis: tp is the physical heat of molten iron, in °C; Si is the silicon content of molten iron, in °C.

[0034] Example: Physical heat 1500℃, [Si]=0.32%, then the physical heat index is... When Ktp≥2.7 (e.g., physical heat 1490℃, [Si]=0.30%), this item is worth 100 points (this item accounts for 35% of the weight).

[0035] (2) The state of the hearth is determined according to the change pattern of the hearth sidewall temperature and the hearth bottom temperature. The hearth activity index is calculated as follows: K = hearth bottom center temperature / average hearth sidewall temperature. The hearth sidewall temperature can be taken as the average temperature below the taphole (closest to the taphole, No. 1 and No. 2, elevation 11.335m). When K ≥ 2.78 (e.g., hearth bottom center temperature (A6) 364℃, hearth sidewall temperature 131℃), this item is 100 points (this item accounts for 25% of the weight).

[0036] (3) The working tapping index of the hearth measures the change in the tapping situation of the hearth by measuring the amount of iron tapped each time, thereby judging the change in the activity of the hearth. The calculation method of the working tapping index of the hearth is as follows: Where Y is the daily iron production of the blast furnace, in tons; and D is the number of times the furnace is blasted per day, in times.

[0037] Example: A blast furnace produces 5500 tons of iron per day; D represents the number of times the furnace is used for blasting per day (10 times). Then, the hearth operating iron tapping index is... When A≥5.5 (e.g., blast furnace daily iron production is 5500t, and the daily blast furnace runs 10 times), this item is worth 100 points (this item accounts for 15% of the weight).

[0038] (4) Wind pressure stability: Take an average value every 10 minutes to calculate the wind pressure deviation (standard deviation) for one day (this item accounts for 5% of the weight).

[0039] (5) Temperature stability of the lower part of the furnace body (the three layers of copper cooling wall, layers 10, 11 and 12 of furnace #1): Take an average value every 5-10 minutes and calculate the temperature deviation value (standard deviation) for one day (this item accounts for 5% of the weight).

[0040] (6) Air permeability index: The daily average value is used in the calculation; (the air permeability index is X. When X / 1650≥1 under the current strong wind control, this item is worth 100 points; when X / 1800≥1 under full wind conditions, this item is worth 100 points), (this item accounts for 5% of the weight).

[0041] (7) FeO content in slag: The daily average value is used in the calculation; (When the FeO content in slag Y, Y / 0.35%≤1, this item is worth 100 points), (This item accounts for 5% of the weight).

[0042] (8) Lower valve box temperature: The daily average value is included in the calculation; when the lower sealing valve seat temperature is >150℃, this item is worth 100 points (this item accounts for 5% of the weight).

[0043] 3) First, organize the above data into a table by day, referring to the "Monthly Report of Comprehensive Blast Furnace Data". Use this table as the raw data to add an application module to perform weighted analysis and connect it to the processing system. Calculate the hearth activity score with a daily time granularity. Adjust the weights every 7 days based on the recent furnace conditions. For example, if there are continuous difficulties in slag and iron discharge, the weight of the iron tapping index will be increased from 15% to 25%.

[0044] 5) Scoring and Early Warning: A comprehensive score is generated and a curve is produced. The comprehensive score for hearth activity is 0-100 points. When the score is below 75 points for two consecutive days, the system recommends "appropriately reducing coke load" or "improving coke quality".

[0045] 6) Long-term optimization: After accumulating 3 months of data, an algorithm is used to predict trends and provide a warning 24 hours in advance of the risk of declining activity.

[0046] 7) A steel plant 1950m 3 After applying this invention to blast furnaces, the early warning of hearth inactivity is brought forward to 6 hours before the abnormality occurs, the accuracy of control measures is improved by 35%, and the number of production reductions caused by furnace condition fluctuations is reduced by 42%.

[0047] The above description is only used to illustrate the technical solution of the present invention and is not intended to limit it. Any other modifications or equivalent substitutions made by those skilled in the art to the technical solution of the present invention, as long as they do not depart from the spirit and scope of the technical solution of the present invention, should be covered within the scope of the claims of the present invention.

Claims

1. A method for evaluating the activity of a blast furnace hearth, characterized in that: Includes the following steps: S1 collects blast furnace production data, including the physical heat temperature of molten iron, silicon content of molten iron, hearth sidewall temperature, furnace bottom center temperature, tapping rate, air pressure, lower furnace body temperature, permeability index, FeO content in slag, and lower valve box temperature. S2, based on the collected blast furnace production data, calculate the following evaluation indicators: (1) Physical heat index: the correlation coefficient between the physical heat of molten iron and silicon content; (2) Sidewall temperature change: The ratio of the average temperature of the furnace bottom center to the average temperature of the furnace hearth sidewall; (3) Iron tapping index: The change in iron tapping in the hearth is measured by the amount of iron tapped each time; (4) Wind pressure stability: standard deviation of wind pressure fluctuation; (5) Lower part temperature stability: Temperature stability index of the lower part of the furnace body; (6) Breathability index: Breathability index deviation rate; (7) FeO content: FeO content in the slag; (8) Lower valve box temperature: Trend of lower valve box temperature; S3. The weights of each indicator are determined by the analytic hierarchy process, and a comprehensive scoring model for hearth activity is constructed with a score of 0-100.

2. The method for evaluating the activity of a blast furnace hearth according to claim 1, characterized in that: The formula for the physical thermal index is: Where tp is the physical heat of molten iron, in °C; Si is the silicon content of molten iron, in %, and this item accounts for 35% of the weight. The trend of this index can reflect the trend of physical heat in a timely manner. The parameter limit is set to 1.4, 1.6, 1.9, 2.1, 2.4 and 2.7 according to the physical heat index value, and the corresponding scores are 50, 60, 70, 80, 90 and 100, and this item accounts for 25% of the weight.

3. The method for evaluating the activity of a blast furnace hearth according to claim 1, characterized in that: The sidewall temperature change is the ratio of the furnace bottom center temperature to the average value of the furnace hearth sidewall temperature; The parameter limits are set to 2.6, 2.63, 2.67, 2.71, 2.75, and 2.78 based on the temperature ratio, with corresponding scores of 50, 60, 70, 80, 90, and 100, and this item has a weight of 15%.

4. The method for evaluating the activity of a blast furnace hearth according to claim 1, characterized in that: The method for calculating the iron tapping index is as follows: Where Y is the daily iron production of the blast furnace, in tons; D is the number of times the furnace is blasted per day, in times. The parameter limits are set to 3.7, 3.9, 4.2, 4.6, 5, and 5.5 based on the iron output index value, with corresponding scores of 50, 60, 70, 80, 90, and 100, and this item has a weight of 5%.

5. The method for evaluating the activity of a blast furnace hearth according to claim 1, characterized in that: The wind pressure stability is calculated by taking an average value every 10 minutes to calculate the wind pressure deviation value for one day. When the value is negative, the absolute value is taken. The parameter limits are set to 5, 6, 7, 8, 9, and 10 based on the wind pressure stability values, with corresponding scores of 100, 90, 80, 70, 60, and 50, and this item accounts for 5% of the weight.

6. The method for evaluating the activity of a blast furnace hearth according to claim 1, characterized in that: The lower temperature stability refers to the temperature stability of the lower part of the furnace body: an average value is taken every 10 minutes, and the temperature deviation value for one day is calculated. The parameter limits are set to 5, 6, 7, 8, 9, 10, 11, and 12 based on the stability values ​​of the lower part of the furnace body. The corresponding scores are 100, 90, 80, 70, 60, 50, 40, and 30, and this item accounts for 5% of the weight.

7. The method for evaluating the activity of a blast furnace hearth according to claim 1, characterized in that: The air permeability index is the air permeability index deviation rate. This reflects the permeability of the blast furnace bed. Here, V is the amount of gas generated in the blast furnace belly area; Q is the gas flow rate, which is the amount of gas passing through a certain cross section of the blast furnace per unit time; and h is the burden thickness, which is the height of the burden inside the blast furnace. The parameter limits are set to 0.86, 0.89, 0.91, 0.94, 0.97, and 1 based on the breathability index value, with corresponding scores of 50, 60, 70, 80, 90, and 100, and this item accounts for 5% of the weight.

8. The method for evaluating the activity of a blast furnace hearth according to claim 1, characterized in that: The FeO content is the ratio of the FeO content in the slag to the benchmark value; The parameter limits are set to 1, 1.14, 1.29, 1.43, 1.57, and 1.71 based on the FeO content values, with corresponding scores of 100, 90, 80, 70, 60, and 50, and this item has a weight of 5%.

9. The method for evaluating the activity of a blast furnace hearth according to claim 1, characterized in that: The lower valve box temperature refers to the temperature change trend of the lower valve box. The parameter limit is set to 100, 110, 120, 130, 140, and 150 based on the lower valve box temperature value, with corresponding fractions of 25, 40, 55, 70, 85, and 100.

10. The method for evaluating the activity of a blast furnace hearth according to claim 1, characterized in that: Introducing a dynamic weight allocation mechanism, the comprehensive score calculation formula is as follows: in, The result is the weighted sum of the scores of each indicator. ,Right now ,in: The weight percentages for each indicator are as follows: physical thermal index, sidewall temperature change, iron tapping index, wind pressure stability, lower temperature stability, air permeability index, FeO content, and lower valve box temperature, with x1+x2+x3+x4+x5+x6+x7+x8=100%; .

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