Method for determining root position of soft melting zone during operation period of blast furnace

Abstract

The invention relates to a method for determining the root position of a soft melting zone during operation of a blast furnace. The method comprises the following steps: acquiring temperature monitoring data of a target blast furnace on each section of cooling wall body; calculating a daily arithmetic average value of the temperature of each section of cooling wall body; calculating the skewness of the daily arithmetic mean value; calculating a Pearson correlation coefficient between daily arithmetic mean values of the temperature of each section of the cooling wall body; and determining the root position of the soft melting zone by using the skewness and the Pearson correlation coefficient. According to the method, the influence of instantaneous temperature fluctuation on a result can be reduced by collecting the temperature monitoring data on each section of cooling wall body and calculating the daily arithmetic mean value, so that the measurement precision of the root position of the soft melting zone is improved.

Description

Technical Field

[0001] The invention relates to the technical field of metallurgy, and in particular to a method for determining the root position of a soft melting zone during operation of a blast furnace. Background Art

[0002] During the operation of the blast furnace, the ore layer and the coke layer descend alternately in the furnace. During the descending process, the coke keeps its shape basically unchanged while the ore is heated by the gas flow, gradually softened and even begins to form initial slag through solid-phase reaction. The permeability decreases rapidly. As the ore continues to heat up, the liquid slag iron formed by melting continues to increase to form a soft melting zone, affecting the output efficiency in the furnace.

[0003] At present, by monitoring and controlling the root position of the soft melting zone, the thermal efficiency of the blast furnace can be effectively improved, the life of the hearth can be extended, and the smelting process can be optimized. However, the existing measurement equipment mostly relies on experience, which leads to a certain error in the operator's judgment of the position, thus affecting the overall performance of the blast furnace. Summary of the invention

[0004] To solve the above problems, an object of an embodiment of the present invention is to provide a method for determining the root position of a soft melting zone during operation of a blast furnace.

[0005] A method for determining the root position of a soft melting zone during blast furnace operation, comprising:

[0006] Step 1: Collect temperature monitoring data on each cooling wall of the target blast furnace;

[0007] Step 2: Calculate the daily arithmetic mean temperature of each cooling wall section;

[0008] Step 3: Calculate the skewness of the daily arithmetic mean;

[0009] Step 4: Calculate the Pearson correlation coefficient between the daily arithmetic mean values ​​of the cooling wall temperatures of each section;

[0010] Step 5: Determine the root position of the soft melting zone using the skewness and Pearson correlation coefficient.

[0011] Preferably, the step 3: calculating the skewness of the daily arithmetic mean comprises:

[0012] Using the formula:

[0013]

[0014] Calculate the skewness of the daily arithmetic mean; where n represents the number of temperature monitoring data samples, s represents the sample standard deviation, and x i represents the value of the i-th sample in the temperature monitoring data, Indicates the daily arithmetic mean of temperature monitoring data.

[0015] Preferably, the step 4: calculating the Pearson correlation coefficient between the daily arithmetic mean values ​​of the temperatures of the cooling wall bodies of each section comprises:

[0016] Using the formula:

[0017]

[0018] Among them, s xy represents the covariance between the daily arithmetic mean values ​​of the cooling wall temperatures in the xth and yth sections, s x represents the standard deviation of the daily arithmetic mean temperature of the cooling wall in the xth section, s y represents the standard deviation of the daily arithmetic mean temperature of the cooling wall in section y, r xy represents the Pearson correlation coefficient, y i represents the value of the i-th sample in the y-th section cooling wall temperature monitoring data, Represents the daily arithmetic mean of the temperature monitoring data of the cooling wall in section y.

[0019] Preferably, the step 5: using the skewness and the Pearson correlation coefficient to determine the root position of the soft melting zone comprises:

[0020] When the Pearson correlation coefficient is within the preset range, the cooling wall of the corresponding section is at the root of the soft melting zone;

[0021] When the skewness is less than 0, the cooling wall body of the corresponding section is located below the soft melting zone;

[0022] When the skewness is greater than 0, the cooling wall body of the corresponding section is located above the soft melting zone.

[0023] According to the specific embodiments provided by the present invention, the present invention discloses the following technical effects:

[0024] The present invention relates to a method for determining the root position of a soft melting zone during blast furnace operation. Compared with the prior art, the present invention reduces the influence of instantaneous temperature fluctuations on the results by collecting temperature monitoring data on each section of cooling wall and calculating the daily arithmetic mean value, thereby improving the measurement accuracy of the root position of the soft melting zone.

[0025] In order to make the above-mentioned objects, features and advantages of the present invention more obvious and easy to understand, preferred embodiments are given below and described in detail with reference to the accompanying drawings. BRIEF DESCRIPTION OF THE DRAWINGS

[0026] In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the drawings required for use in the embodiments or the description of the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying creative work.

[0027] Figure 1 A flow chart of a method for determining the root position of a soft melting zone during blast furnace operation provided by the present invention;

[0028] Figure 2 A schematic diagram of the blast furnace structure provided by the present invention;

[0029] Figure 3 A histogram of the temperature mean values ​​of the six cooling wall sections provided by the present invention;

[0030] Figure 4 A histogram of the temperature mean values ​​of 8 sections of the cooling wall provided by the present invention;

[0031] Figure 5 A histogram of the mean temperature values ​​of 9 sections of the cooling wall provided by the present invention;

[0032] Figure 6 This is a graph of the Pearson correlation coefficient calculation results provided by the present invention.

[0033] Explanation of symbols:

[0034] 1. Charging device, 2. Coke window, 3. Cooling wall section 10, 4. Cooling wall section 9, 5. Cooling wall section 8, 6. Cooling wall section 7, 7. Cooling wall section 6, 8. Tap hole, 9. Molten iron, 10. Slag, 11. Tuyere, 12. Hot air surrounding pipe, 13. Soft melting zone. DETAILED DESCRIPTION

[0035] In the description of the present invention, it should be understood that the terms "center", "longitudinal", "lateral", "length", "width", "thickness", "up", "down", "front", "back", "left", "right", "vertical", "horizontal", "top", "bottom", "inside", "outside", "clockwise", "counterclockwise" and the like indicate orientations or positional relationships based on the orientations or positional relationships shown in the accompanying drawings, and are only for the convenience of describing the present invention and simplifying the description, rather than indicating or implying that the referred device or element must have a specific orientation, be constructed and operated in a specific orientation, and therefore should not be understood as limiting the present invention.

[0036] In addition, the terms "first" and "second" are used for descriptive purposes only and should not be understood as indicating or implying relative importance or implicitly indicating the number of the indicated technical features. Therefore, the features defined as "first" and "second" may explicitly or implicitly include one or more of the features. In the description of the present invention, the meaning of "plurality" is two or more, unless otherwise clearly and specifically defined.

[0037] In the present invention, unless otherwise clearly specified and limited, the terms "installed", "connected", "connected", "fixed" and the like should be understood in a broad sense, for example, it can be a fixed connection, a detachable connection, or an integral connection; it can be a mechanical connection or an electrical connection; it can be a direct connection, or it can be an indirect connection through an intermediate medium, or it can be the internal communication of two components. For ordinary technicians in this field, the specific meanings of the above terms in the present invention can be understood according to specific circumstances.

[0038] See also Figure 1 , a method for determining the root position of a soft melting zone during blast furnace operation, comprising:

[0039] Step 1: Collect temperature monitoring data on each cooling wall of the target blast furnace;

[0040] Step 2: Calculate the daily arithmetic mean temperature of each cooling wall section;

[0041] Step 3: Calculate the skewness of the daily arithmetic mean;

[0042] Among them, in step 3, the formula is used:

[0043]

[0044] Calculate the skewness of the daily arithmetic mean; where n represents the number of temperature monitoring data samples, s represents the sample standard deviation, and x i represents the value of the i-th sample in the temperature monitoring data, Indicates the daily arithmetic mean of temperature monitoring data.

[0045] Step 4: Calculate the Pearson correlation coefficient between the daily arithmetic mean values ​​of the cooling wall temperatures of each section;

[0046] In step 4, the formula is used:

[0047]

[0048] Calculate the Pearson correlation coefficient between the daily arithmetic mean values ​​of the temperature of each cooling wall section; where s xy represents the covariance between the daily arithmetic mean values ​​of the cooling wall temperatures in the xth and yth sections, s xrepresents the standard deviation of the daily arithmetic mean temperature of the cooling wall in the xth section, s y represents the standard deviation of the daily arithmetic mean temperature of the cooling wall in section y, r xy represents the Pearson correlation coefficient, y i represents the value of the i-th sample in the y-th section cooling wall temperature monitoring data, Represents the daily arithmetic mean of the temperature monitoring data of the cooling wall in section y.

[0049] Step 5: Determine the root position of the soft melting zone using the skewness and Pearson correlation coefficient.

[0050] Furthermore, the step 5: using the skewness and the Pearson correlation coefficient to determine the root position of the soft melting zone includes:

[0051] When the Pearson correlation coefficient is within the preset range, the cooling wall bodies of the corresponding sections are on the same side of the soft melting zone;

[0052] When the skewness is less than 0, the cooling wall body of the corresponding section is located below the soft melting zone;

[0053] When the skewness is greater than 0, the cooling wall body of the corresponding section is located above the soft melting zone.

[0054] The following is a further description of a method for determining the root position of a soft melting zone during blast furnace operation according to the present invention in conjunction with a specific embodiment:

[0055] 1. Collect the temperature monitoring data of each point on each section of the blast furnace wall. Collect the data of the temperature monitoring points of each section of the cooling wall in the form of hourly average.

[0056] 2. Statistic the collected data by segment and calculate the daily arithmetic mean of the wall temperature of that segment.

[0057] 3. Draw a histogram of the mean temperature of each wall section.

[0058] 4. Calculate the descriptive statistics (mainly including mean, standard deviation, range, interquartile range, skewness) of the daily arithmetic mean of the wall temperature of each cooling wall. The obvious left deviation (skewness < 0) is below the soft melting zone, and the position above the soft melting zone will have an obvious right deviation (skewness > 0) due to the shedding of slag skin.

[0059] 5. Calculate the Pearson correlation coefficient between the mean values ​​of the wall temperature of each section. The area where the Pearson correlation data show obvious correlation is on the same side of the soft melting zone.

[0060] 6. Calculate descriptive statistics for the daily arithmetic mean of wall temperature.

[0061] According to the descriptive statistics of the hourly average wall temperature as shown in Table 1-2 below, it can be seen that the average wall temperature of Section 6 is the lowest (<43°C, and the other sections are all >43°C), but affected by the hot air sent in from the tuyere and the amount of slag iron gathered in the furnace, the wall temperature range is the largest, and the stability index represented by the interquartile range is also poor, indicating that the stability of this part is poor. The range and interquartile range of Section 7 are both low, indicating that the temperature stability of this part is better. From the perspective of skewness, except for Section 6, all are right-skewed. This shows that Section 6 and the above sections are blocked by the soft melting zone, and the working environment is very different.

[0062] Table 1

[0063] variable N N* Mean Standard Deviation Minimum Lower quartile median Upper quartile Maximum Very bad Interquartile range 6-segment mean 176 0 42.507 3.130 29.056 41.127 43.172 44.548 48.202 19.146 3.421 7-segment mean 176 0 44.068 1.434 41.252 43.082 43.972 44.837 49.932 8.681 1.755 8-segment mean 176 0 44.805 1.681 41.191 43.702 44.561 45.718 51.096 9.905 2.017 9-segment mean 176 0 46.306 1.574 42.035 45.172 46.034 47.092 53.353 11.318 1.920 10-segment mean 176 0 46.262 1.801 41.852 45.028 45.934 47.288 53.719 11.867 2.261

[0064] Table 2

[0065]

[0066]

[0067] See also Figure 2-5 From the histogram of the mean temperature of each section wall, it can be seen that the 6th section wall has an obvious left-biased distribution, and the rest of the wall has a right-biased distribution, indicating that the 6th section cooling wall is still below the soft melting zone. It is mainly affected by direct reduction. This area absorbs a lot of heat, the wall temperature is low, and is greatly affected by the whirlpool zone formed in front of the tuyere and the iron tapping, and the wall temperature fluctuates greatly. The range and interquartile range of the 7th section wall are the smallest. It can be seen that the temperature of this part is located at the root of the soft melting zone and is less affected by the impact of coal gas and slag iron. The wall temperature is relatively stable. The wall above the 7th section is prone to slag skin shedding, resulting in more high points in the daily average value, increasing the frequency of high temperature points on the right side of the histogram, which is reflected in the positive skewness.

[0068] Calculate the Pearson correlation coefficient of the daily average temperature of each section wall, such as Figure 6 As shown. It can be seen that there is no obvious correlation between the 6 sections below the soft melting zone and all the wall bodies due to the isolation of the soft melting zone (correlation coefficient < 0.5). The 7th section where the root of the soft melting zone is located also has no obvious correlation with other wall bodies. Combined with the range and interquartile range of this part, the stability of this part shows that this part is the root of the soft melting zone. The root of the soft melting zone is upward and out of the influence of the root of the soft melting zone. It is mainly affected by the high-temperature coal gas flow passing through the focal window. The influence of coal gas flow and temperature changes on the mean temperature of the wall body above the root of the soft melting zone is in the same direction, that is, both increase or decrease. There is a significant correlation between the 8th section and the 9th section, and the 9th section and the 10th section (the correlation coefficient is high, 0.693 and 0.807 respectively), indicating that from the 8th section, it has entered the position above the root of the soft melting zone, and the influence on the wall body above is obviously correlated.

[0069] The above is only a specific embodiment of the present invention, but the protection scope of the present invention is not limited thereto. Any technical solution that can be easily thought of by a person skilled in the art within the technical scope disclosed by the present invention should be included in the protection scope of the present invention. Therefore, the protection scope of the present invention shall be based on the protection scope of the claims.

Claims

1. A method for determining the root position of a soft melting zone during blast furnace operation, characterized in that: include: Step 1: Collect temperature monitoring data on each cooling wall of the target blast furnace; Step 2: Calculate the daily arithmetic mean temperature of each cooling wall section; Step 3: Calculate the skewness of the daily arithmetic mean; Step 4: Calculate the Pearson correlation coefficient between the daily arithmetic mean values ​​of the cooling wall temperatures of each section; Step 5: Determine the root position of the soft melting zone using the skewness and Pearson correlation coefficient.

2. The method for determining the root position of the soft melting zone during blast furnace operation according to claim 1, characterized in that: The step 3: calculating the skewness of the daily arithmetic mean, includes: Using the formula: Calculate the skewness of the daily arithmetic mean; where n represents the number of temperature monitoring data samples, s represents the sample standard deviation, and x i represents the value of the i-th sample in the temperature monitoring data, Indicates the daily arithmetic mean of temperature monitoring data.

3. The method for determining the root position of the soft melting zone during blast furnace operation according to claim 2, characterized in that: The step 4: calculating the Pearson correlation coefficient between the daily arithmetic mean values ​​of the temperatures of the cooling wall bodies of each section, includes: Using the formula: Among them, s xy represents the covariance between the daily arithmetic mean values ​​of the cooling wall temperatures in the xth and yth sections, s x represents the standard deviation of the daily arithmetic mean temperature of the cooling wall in the xth section, s y represents the standard deviation of the daily arithmetic mean temperature of the cooling wall in section y, r xy represents the Pearson correlation coefficient, y i represents the value of the i-th sample in the y-th section cooling wall temperature monitoring data, and y represents the daily arithmetic mean value in the y-th section cooling wall temperature monitoring data.

4. The method for determining the root position of the soft melting zone during blast furnace operation according to claim 3, characterized in that: The step 5: using the skewness and the Pearson correlation coefficient to determine the root position of the soft melting zone includes: When the Pearson correlation coefficient is within the preset range, the cooling wall of the corresponding section is at the root of the soft melting zone; When the skewness is less than 0, the cooling wall body of the corresponding section is located below the soft melting zone; When the skewness is greater than 0, the cooling wall body of the corresponding section is located above the soft melting zone.

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