Method for judging falling of masonry protection bricks after blowing-in of blast furnace

Abstract

The invention discloses a method for monitoring a phenomenon that a large number of protective bricks fall after blast furnace blow-in, which comprises the following steps of: confirming a normal operation interval of wall body temperature during the complete existence period of the protective bricks according to a statistical principle, counting the Al2O3 content of furnace slag during the existence period of the protective bricks, and confirming a normal operation range of the Al2O3 of the furnace slag; once the temperature of the wall body is abnormally increased after the protection bricks fall off, the situation that a large number of protection bricks in front of the cooling wall of the section fall off can be judged when the range value of the same section of wall body in the circumferential direction is abnormally increased and the Al2O3 content of slag is abnormally increased; moreover, the wall body temperature rise caused by normal slag crust falling and the slag Al2O3 content rise caused by the abnormal Al2O3 content of the raw material entering the furnace can be distinguished, and misjudgment is prevented.

Description

Technical Field

[0001] The invention relates to a method for judging whether masonry protection bricks fall after a blast furnace is opened. Background Art

[0002] A layer of high-aluminum protective bricks will be built in front of the cooling wall of a newly built blast furnace to protect the cooling wall and prevent the opening charge from causing excessive impact on the cooling wall due to the large drop during the loading process. After the furnace is opened, the protective bricks will gradually fall off. The large amount of protective bricks falling off will cause fluctuations in the edge airflow. The protective bricks contain more than 40% Al2O3. After a large area of ​​protective bricks fall off, the Al2O3 content in the slag will increase rapidly, and the corresponding slag fluidity will deteriorate sharply. The deterioration of slag fluidity will further lead to poor central airflow and even cause abnormal furnace conditions. Therefore, how to promptly detect the situation where protective bricks begin to fall in large numbers and take corresponding measures in a timely manner is an important task to maintain smooth furnace conditions after the blast furnace has been opened for a period of time. Summary of the invention

[0003] The purpose of the present invention is to provide a monitoring method that can promptly and quickly detect the phenomenon of a large number of protective bricks falling in front of the wall after the blast furnace is opened, so as to solve the problem that the failure to promptly detect the falling of protective bricks after the furnace is opened leads to abnormal airflow distribution and even abnormal furnace conditions.

[0004] In order to solve the above technical problems, the present invention adopts the following technical solutions:

[0005] The present invention provides a method for judging whether masonry protection bricks fall after a blast furnace is opened, comprising:

[0006] By analyzing the feedback data of thermocouples of walls with protective bricks, the operating range in which the protective bricks are still intact is determined;

[0007] The Al2O3 content in the slag within the operating range where the protective bricks are intact is counted 30-100 times; and the normal operating range of the Al2O3 content in the slag is determined by statistical methods;

[0008] The daily average values ​​of the thermocouple data of the wall body during the period when the smelting intensity reaches the normal level and the protective bricks are intact after the furnace is opened are counted for 25-50 days;

[0009] Statistics are collected on the thermocouple data of each section of the wall when the smelting intensity reaches the normal level and the protective bricks are intact after the furnace is opened; the mean and range of the thermocouple temperature of the same section are calculated, and the normal operating range of the two parameters is determined;

[0010] When the average wall temperature on the same section of the cooling wall exceeds the upper limit of the normal operating range, the extreme difference of the wall temperature in the same circumferential direction exceeds the upper limit of the normal operating range, and the Al2O3 content in the slag exceeds the upper limit of the normal operating range, it is determined that a large number of protective bricks built outside the cooling wall of this section have fallen off.

[0011] Furthermore, the normality test and descriptive statistics of the Al2O3 content in 50 slags were conducted: during the period when the protective bricks were present and intact, the Al2O3 content in the slag conformed to the normal distribution with a mean of 13.84 and a standard deviation of 0.1828.

[0012] Furthermore, according to the probability density function of the normal distribution of the Al2O3 content in the slag, it is calculated that if the protective bricks continue to exist stably and the Al2O3 content of the raw materials entering the furnace does not change abnormally, the probability that the Al2O3 content in the slag is less than 14.72 is 99%.

[0013] Furthermore, once the wall temperature rises abnormally after the protective bricks fall, the abnormal increase in the extreme difference value in the circumferential direction on the same section of the wall and the abnormal increase in the Al2O3 content in the slag can be judged as a large number of protective bricks have fallen in front of this section of the cooling wall.

[0014] Furthermore, it is possible to distinguish between the increase in wall temperature caused by normal slag skin falling and the increase in Al2O3 content in the slag caused by abnormal Al2O3 content in the raw materials entering the furnace, thereby preventing misjudgment.

[0015] Compared with the prior art, the beneficial technical effects of the present invention are:

[0016] The present invention confirms the normal operating range of the wall temperature during the complete existence of the protective bricks based on statistical principles, and counts the Al2O3 content of the slag during the existence of the protective bricks, to confirm the normal operating range of the slag Al2O3. Once the wall temperature rises abnormally after the protective bricks fall, the abnormal increase in the extreme difference value in the circumferential direction on the same section of the wall combined with the abnormal increase in the Al2O3 content of the slag can be judged as a large number of protective bricks falling in front of the cooling wall of this section. And it can distinguish between the increase in wall temperature caused by the normal falling of slag skin and the increase in the Al2O3 content of the slag caused by the abnormal Al2O3 content of the raw materials entering the furnace, to prevent misjudgment. BRIEF DESCRIPTION OF THE DRAWINGS

[0017] The present invention will be further described below in conjunction with the accompanying drawings.

[0018] Figure 1 For radar chart;

[0019] Figure 2 is a scatter plot of mean and date;

[0020] Figure 3 It is a scatter plot of range and date;

[0021] Figure 4 It is a scatter plot of Al2O3 and date. DETAILED DESCRIPTION

[0022] Example

[0023] The 9th section of cooling wall is built with protective bricks. The temperature measurement thermocouple data of this section of cooling wall is used as an example.

[0024] A monitoring method for the phenomenon of a large number of protective bricks falling after the blast furnace is opened, specifically comprising:

[0025] A. The temperature measurement data of the 9 cooling walls with protective bricks on the outside were selected for analysis from August 28 to September 24, 2014. First, a radar chart was made, such as Figure 1 As shown, from Figure 1 It can be seen from the above that the temperature of each thermocouple is stable and smooth in the operating range.

[0026] The normality test was performed on the range of the daily average temperature of 8 thermocouples in 9 sections and the daily average temperature of 8 single-point temperature measuring point pairs. The P values ​​were 0.098 and 0.089, both > 0.05, indicating that they were normally distributed, stable and under control, and could be used as samples during the existence of the protective bricks.

[0027] B. Normality test and descriptive statistics were performed on the Al2O3 content in 50 slags during the period from August 28 to September 24, 2014: During the period when the protective bricks were present and intact, the Al2O3 content in the slags conformed to a normal distribution with a mean of 13.84 and a standard deviation of 0.1828.

[0028] According to the probability density function of the normal distribution of Al2O3 content in the slag, it can be calculated that if the protective bricks continue to exist stably and there is no abnormal change in the Al2O3 content of the raw materials entering the furnace, the probability that the Al2O3 content in the slag is less than 14.72 is 99%.

[0029] C. The mean and range of the daily temperature measurement data of the same 9 sections and 8 thermocouples are normally distributed with a mean of 45.65, a standard deviation of 0.3133 and a mean of 2.419, a standard deviation of 0.8915 (the P values ​​of the normality test are all > 0.05).

[0030] D. According to the probability density function of the normal distribution of the mean and range of the 9-section wall temperature, it can be calculated that if the protective bricks continue to exist stably, the daily average value of the 9-section wall galvanic temperature will be <46.38 in 99% of the cases, and the range of the wall temperature between the previous and next two days will be <4.493 in 99% of the cases.

[0031] E. Draw a scatter plot of the daily average values ​​of the wall temperature for 9 sections based on the mean value of 45.65 and the upper limit value of 46.38, such as Figure 2 As shown; based on 2.419 and 4.493, draw the extreme difference scatter diagram of 9 sections of wall temperature, as shown Figure 3 shown.

[0032] From the above two scatter plots, we can see that starting from point 30 on the horizontal axis, the average wall temperature exceeds the upper limit and the daily average range of 8 temperature measuring couples in 9 sections on that day also exceeds the upper limit. This indicates that protective bricks have fallen off locally in the circumferential direction, the thinning of the lining has caused the temperature of the 9 sections of the wall to rise, and the uneven falling in the circumferential direction has caused the temperature range to increase.

[0033] A scatter plot of the Al2O3 content in the slag is drawn based on the mean value of 13.88 and the upper limit of 14.27; as shown in the following figure: Starting from 35 o'clock, the Al2O3 content in the slag increases significantly. If the protective bricks do not fall off, the probability of exceeding 14.27 in the slag is 1%. Figure 4 It can be seen that the continuous occurrence of exceeding the upper limit of 14.27 (low probability events occur continuously, indicating that the previous stable situation has been destroyed), indicating that the large-scale shedding of protective bricks has obviously affected the slag. Combined with the average wall temperature and the extreme situation, it can be seen that on the date represented by point 30 in the figure, protective bricks began to fall off locally in front of the 9th cooling wall, but not in large quantities (the Al2O3 content in the slag did not increase abnormally), and on the date represented by point 35, protective bricks began to fall off in large quantities.

[0034] The present invention confirms the normal operating range of the wall temperature during the complete existence of the protective bricks based on statistical principles, and counts the Al2O3 content of the slag during the existence of the protective bricks, to confirm the normal operating range of the slag Al2O3. Once the wall temperature rises abnormally after the protective bricks fall, the abnormal increase in the extreme difference value in the circumferential direction on the same section of the wall combined with the abnormal increase in the Al2O3 content of the slag can be judged as a large number of protective bricks falling in front of the cooling wall of this section. And it can distinguish between the increase in wall temperature caused by the normal falling of slag skin and the increase in the Al2O3 content of the slag caused by the abnormal Al2O3 content of the raw materials entering the furnace, to prevent misjudgment.

[0035] The embodiments described above are only descriptions of the preferred modes of the present invention, and are not intended to limit the scope of the present invention. Without departing from the design spirit of the present invention, various modifications and improvements made to the technical solutions of the present invention by ordinary technicians in this field should all fall within the protection scope determined by the claims of the present invention.

Claims

1. A method for judging the falling of masonry protection bricks after the blast furnace is opened, characterized in that: include: By analyzing the feedback data of thermocouples of walls with protective bricks, the operating range in which the protective bricks are still intact is determined; The Al2O3 content in the slag within the operating range where the protective bricks are intact is counted 30-100 times; and the normal operating range of the Al2O3 content in the slag is determined by statistical methods; The daily average values ​​of the thermocouple data of the wall body during the period when the smelting intensity reaches the normal level and the protective bricks are intact after the furnace is opened are counted for 25-50 days; Statistics are collected on the thermocouple data of each section of the wall when the smelting intensity reaches the normal level and the protective bricks are intact after the furnace is opened; the mean and range of the thermocouple temperature of the same section are calculated, and the normal operating range of the two parameters is determined; When the average wall temperature on the same section of the cooling wall exceeds the upper limit of the normal operating range, the extreme difference of the wall temperature in the same circumferential direction exceeds the upper limit of the normal operating range, and the Al2O3 content in the slag exceeds the upper limit of the normal operating range, it is determined that a large number of protective bricks built outside the cooling wall of this section have fallen off.

2. The method for judging the falling of masonry protection bricks after the blast furnace is opened according to claim 1, characterized in that: Normality test and descriptive statistics were performed on the Al2O3 content in 50 slags: when the protective bricks were present and intact, the Al2O3 content in the slag conformed to a normal distribution with a mean of 13.84 and a standard deviation of 0.1828.

3. The method for judging the falling of masonry protection bricks after the blast furnace is opened according to claim 2, characterized in that: According to the probability density function of the normal distribution of Al2O3 content in the slag, it is calculated that if the protective bricks continue to exist stably and the Al2O3 content of the raw materials entering the furnace does not change abnormally, the probability that the Al2O3 content in the slag is less than 14.72 is 99%.

4. The method for judging the falling of masonry protection bricks after the blast furnace is opened according to claim 1, characterized in that: Once the wall temperature rises abnormally after the protective bricks fall, the circumferential extreme value on the same section of the wall increases abnormally, and the Al2O3 content in the slag increases abnormally, it can be determined that a large number of protective bricks have fallen in front of this section of the cooling wall.

5. The method for judging the falling of masonry protection bricks after the blast furnace is opened according to claim 1, characterized in that: It can distinguish the increase in wall temperature caused by normal slag skin falling and the increase in slag Al2O3 content caused by abnormal Al2O3 content of raw materials entering the furnace, thus preventing misjudgment.

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