A blast furnace heat load control method

Abstract

This invention relates to a method for controlling the heat load of a blast furnace, comprising the steps of (1) calculating and controlling the 24-hour heat load stability index between 30 and 120; (2) controlling the coke load at the edge of the blast furnace charging assembly between 4.0 and 10.0; and (3) calculating and controlling the heat load of the blast furnace gas per unit volume between 0.10 and 0.25 MJ / m³. 3 (4) The cooling water volume of the blast furnace body shall be dynamically adjusted according to the heat load value of the gas per unit volume of the blast furnace; (5) The water volume shall reach the design upper limit and the heat load value of the gas per unit volume of the blast furnace shall be higher than 0.25 MJ / m 3 Increasing the length of the tuyeres reduces the effective belly angle by 20-150mm; the unit volume of gas heat load is proposed, combining the total heat load of the blast furnace with the smelting intensity of the blast furnace, realizing dynamic adjustment of the heat load, extending the service life of the blast furnace cooling wall, reducing water leakage caused by the damage of the cooling wall during the first generation of furnace service, and enabling the blast furnace to maintain a reasonable blast furnace slag skin state for a long time, thereby improving the stability and operating quality of the blast furnace.

Description

Technical Field

[0001] This invention relates to the field of iron and steel smelting technology, and in particular to a method for controlling the heat load of a blast furnace. Background Technology

[0002] The level of blast furnace heat load not only directly affects the blast furnace lifespan, but also has a significant impact on the stability of blast furnace slag skin, heat, and gas flow distribution. Currently, most blast furnaces in China lack methods and standards for heat load control. The cooling regime, such as water volume and water rate, is determined at the initial design stage of the blast furnace and remains basically unchanged throughout one generation of furnace life. This situation makes it difficult to meet the actual production conditions of different furnace service stages and different gas flow characteristics, thus making it difficult to maximize the longevity of blast furnace cooling equipment and the stability of the slag skin system.

[0003] Chinese patent CN114134267A discloses a furnace temperature control method to cope with blast furnace heat load fluctuations. Based on the changing characteristics of actual blast furnace operating parameters, it accurately reflects the fuel ratio adjustment under different heat load changes to ensure stable furnace temperature. This method is fully utilized in blast furnace thermal regime adjustments and can guide blast furnace operation when there are large fluctuations in furnace conditions. According to this invention, it can effectively provide a basis for blast furnace recovery operation during furnace condition fluctuations, reducing operational errors and accelerating the recovery process. However, this patent mainly controls furnace temperature; the blast furnace heat load still fluctuates and is not stable.

[0004] Chinese patent CN114015825B discloses a method for monitoring abnormal blast furnace heat load based on an attention mechanism. The method first involves data acquisition and preprocessing, then constructing a prediction model based on the attention mechanism, comprising a two-layer one-dimensional convolutional neural network structure and a single-layer bidirectional long short-term memory network structure. The prediction model is then trained using a joint training mechanism. Finally, a 1DCNN with an added attention mechanism is used to extract features of significant abnormal fluctuations in the input parameters. The time-dimensional memory function of a BiLSTM is then utilized to achieve online monitoring. This invention considers the quality of the collected historical data and designs a two-stage data preprocessing method, which can significantly improve the accuracy of predicting the trend state when the heat load changes drastically, grasp the operating status of the blast furnace equipment, and ensure the continuity and stability of the blast furnace ironmaking process. However, this patent is mainly used for monitoring abnormal blast furnace heat load conditions and cannot stably control the blast furnace heat load. Summary of the Invention

[0005] This invention provides a blast furnace heat load control method. It proposes a blast furnace heat load stability index and links the blast furnace cooling water volume, the blast furnace heat load stability index, and the blast furnace gas heat load per unit volume for correlated control. Based on the magnitude of the blast furnace heat load stability index and the gas heat load per unit volume, it dynamically adjusts the edge coke load in the blast furnace charging system and the tuyeres length parameters in the blast furnace blowing system. This dynamic adjustment method transforms the originally fixed cooling intensity of the blast furnace into dynamic control, effectively linking the adjustment of blast furnace system parameters with the specific heat load state of the blast furnace. This ultimately achieves a longer overall blast furnace lifespan, maintains a reasonable blast furnace slag condition over a long period, improves blast furnace stability and operational quality, and maintains a reasonable gas distribution and fuel consumption level.

[0006] To achieve the above objectives, the present invention employs the following technical solution:

[0007] A method for controlling the heat load of a blast furnace includes the following steps:

[0008] (1) Calculate the heat load stability index and control the 24-hour heat load stability index between 30 and 120. The calculation formula is as follows:

[0009]

[0010] Where S is the heat load stability index, X1 is the heat load value in the first hour of the day (MJ / h), and m is the average heat load value in 24 hours (MJ / h).

[0011] (2) Control the coke load at the edge of the blast furnace charging point between 4.0 and 10.0;

[0012] (3) Calculate and control the heat load of blast furnace gas per unit volume within the range of 0.10–0.25 MJ / m³. 3 ;

[0013] (4) The cooling water volume of the blast furnace body is dynamically adjusted according to the heat load value of the gas per unit volume of the blast furnace;

[0014] (5) The water volume reaches the design limit and the heat load of the blast furnace gas per unit volume is higher than 0.25 MJ / m³. 3 Increase the length of the air vent by 20-150mm.

[0015] Furthermore, in step (2), for every 10 that the heat load stability index exceeds the upper limit or falls below the lower limit, the edge coke load increases or decreases by 0.8 to 1.5.

[0016] Furthermore, the heat load per unit volume of blast furnace gas is equal to the blast furnace 24-hour heat load divided by the gas volume in the furnace belly, as shown in the following formula:

[0017]

[0018] Furthermore, the adjustment amount of the blast furnace cooling water volume shall be adjusted such that for every 0.02 MJ / m exceeding the upper limit or falling below the lower limit... 3 Increase or decrease cooling water volume by 200m 3 / h, 0~0.02MJ / m 3 Within 0.02 MJ / m 3 Increase or decrease.

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

[0020] 1) The heat load stability index is proposed, which is the first quantitative description of the stability of blast furnace heat load. The heat load per unit volume of gas is proposed, which combines the total amount of blast furnace heat load with the smelting intensity of blast furnace. This changes the previous problem of only analyzing the numerical value of blast furnace heat load while ignoring the amount of gas in the blast furnace itself. Both indicators are incorporated into a dynamic control method, and a control benchmark is established from the two dimensions of heat load stability and numerical rationality.

[0021] 2) By establishing a two-dimensional control method, the service life of the blast furnace cooling wall is extended, and water leakage caused by the damage of the cooling wall during the first generation of furnace service is reduced;

[0022] 3) By using the heat load stability index and the heat load per unit volume of gas in the blast furnace as the standard, the heat load of the blast furnace body is dynamically adjusted, so that the heat load of the blast furnace body changes from passive tracking to active control, and the blast furnace maintains a reasonable slag skin state in the long term, thereby improving the stability and operation quality of the blast furnace. Detailed Implementation

[0023] The specific embodiments of the present invention will be further described below:

[0024] A steel plant with a capacity of 2580m 3 Taking a blast furnace as an example, the present invention provides a blast furnace heat load control method, comprising the following steps:

[0025] (1) Calculate and control the 24-hour heat load stability index between 30 and 120. The heat load stability index is used to represent the stability of the blast furnace heat load. Its value is the variance of the hourly heat load over 24 hours / 1,000,000. The formula for calculating the heat load stability index is as follows:

[0026]

[0027] Where S is the heat load stability index, X1 is the heat load value in the first hour of the day (MJ / h), and m is the 24-hour average heat load value (MJ / h). The 24-hour heat load is shown in Table 1 below.

[0028] Table 1

[0029] time 0:00 1:00 2:00 3:00 4:00 5:00 6:00 7:00 8:00 9:00 10:00 11:00 Heat load (MJ / J) 79748 86959 81046 77441 73403 79854 71384 70086 73980 69798 82587 69653 time 12:00 13:00 14:00 15:00 16:00 17:00 18:00 19:00 20:00 21:00 22:00 23:00 Heat load (MJ / J) 70519 68932 70230 63452 79171 86093 93015 105994 98541 82587 104408 101210

[0030] The S value was calculated to be 140 using Table 1 and the S calculation formula. 140 exceeds the upper limit of 120 for the 24-hour heat load stability index, which proves that the fluctuation range of the heat load of the blast furnace exceeds the standard within 24 hours.

[0031] (2) Control the coke load at the edge of the blast furnace charging feeder between 4.0 and 10.0. The coke load at the edge of the blast furnace charging feeder is the ratio of ore weight to coke weight. For every 10 units that the heat load stability index S exceeds the upper limit or falls below the lower limit, the coke load at the edge increases or decreases by 0.8 to 1.5. Therefore, adjust the coke load at the edge based on the obtained S value of 140 to control the fluctuation range of the heat load. The current charging matrix of this blast furnace is shown in Table 2.

[0032] Table 2

[0033]

[0034] Wherein, the tilt angle is the inclination angle of the blast furnace charging chute, J represents coke, J represents ore, the ore batch weight is 65.0t / batch, the coke batch weight is 13.95t / batch, the total number of ore charging rings is 13 rings according to Table 2, and the number of ore charging rings in 10 rings is 3 rings, the total number of coke charging rings is 17.5 rings according to Table 2, and the number of coke charging rings in 10 rings is 3 rings, calculate the current edge coke load, the edge coke load is taken as the weight ratio of ore to coke at the 10th ring position:

[0035]

[0036]

[0037] Therefore, the edge coke load is: 10 ring ore weight / 10 ring coke weight = 15 / 2.39 = 6.27. Since the S value is higher than the upper limit of 20, the edge coke load needs to be increased by 0.8 to 1.5. The specific operation is to reduce the weight of 10 rings of coke by changing the 10th ring position in the material distribution matrix table 2 from 3 rings of coke to 2 rings of coke, thereby achieving the goal of reducing the weight of 10 rings of coke. After changing the 10th ring of coke in the matrix from 3 rings to 2 rings, the coke load increases from 6.27 to 8.87.

[0038] (3) Calculate and control the heat load of blast furnace gas per unit volume within the range of 0.10–0.25 MJ / m³. 3 According to the formula The average daily gas volume in the blast furnace was V. 腹 5147m 3 / min, average heat load m is 80837MJ / h, calculate K as

[0039] (4) The cooling water volume of the blast furnace body is dynamically adjusted according to the K value. The adjustment amount of the cooling water volume of the blast furnace body exceeds the upper limit or falls below the lower limit by 0.02 MJ / m. 3 Increase or decrease cooling water volume by 200m 3 / h, 0~0.02MJ / m 3 Within 0.02 MJ / m 3 The calculated heat load K value per unit volume of blast furnace gas, whether increased or decreased, is 0.261 MJ / m³. 3 Exceeding the upper limit of 0.25 MJ / m 3 Total 0.011 MJ / m 3 Cooling water volume is 3200m³ 3 At the current gas volume, the absolute level of the blast furnace's heat load is too high, and its cooling water volume needs to be increased from 3200 m³ / min. 3 / min, increased to 3400m 3 / min.

[0040] (5) The water volume reaches the upper limit of the blast furnace design, and the heat load value K of the gas per unit volume of the blast furnace is higher than 0.25 MJ / m³. 3 Increase the length of the air vent by 20-150mm.

[0041] The above embodiments are implemented based on the technical solution of the present invention, providing detailed implementation methods and specific operation processes. However, the scope of protection of the present invention is not limited to the above embodiments. Unless otherwise specified, the methods used in the above embodiments are conventional methods.

Claims

1. A method for controlling the thermal load of a blast furnace, characterized in that, It comprises the following steps: (1) calculating the thermal load stability index, and controlling the 24-hour thermal load stability index between 30-120, the calculation formula is as follows: （1） Wherein, S is the thermal load stability index, X1 is the thermal load value of the first hour per day MJ / h, and m is the 24-hour average thermal load value MJ / h; (2) controlling the edge coke load of the blast furnace between 4.0-10.0; (3) calculating and controlling the heat load of unit volume of blast furnace gas in the range of 0.10-0.25 MJ / m 3 ; the heat load of unit volume of blast furnace gas is equal to the average heat load of blast furnace in 24 hours / the volume of bosh gas, and the formula is as follows: （2） wherein K is the heat duty of the blast furnace per unit volume of gas MJ / m 3 , is the amount of gas in the bosh m 3 / min; (4) the blast furnace shaft cooling water quantity is dynamically adjusted according to the unit volume coal gas thermal load value of the blast furnace; (5) The water quantity reaches the design upper limit and the unit volume gas heat load value of the blast furnace is higher than 0.25 MJ / m 3 , increase the tuyere length by 20-150 mm.

2. A method of controlling the heat load of a blast furnace according to claim 1, characterized by, In the step (2), the edge coke load is correspondingly increased or decreased by 0.8-1.5 when the thermal load stability index exceeds the upper limit or is lower than the lower limit by 10.

3. The method of controlling the heat load of a blast furnace according to claim 1, wherein In step (4), for every 0.02 MJ / m³ of blast furnace gas heat load per unit volume exceeding the upper limit or falling below the lower limit... 3 Increase or decrease cooling water volume by 200m 3 / h, 0~0.02MJ / m 3 Within 0.02 MJ / m 3 Increase or decrease.

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