JPS5848615A - Detection for slopping in converter - Google Patents

Abstract

PURPOSE:To control the yield of converter operations according to the state of slopping by detecting the slopping in the converter and the fluctuations in the temps. on the surfaces in the upper and lower parts of the converter according to the drop of slopping slag. CONSTITUTION:The surface temp. in an upper part A including the converter port 16 of a converter body 10 is detected with a radiation thermometer 12 for the upper part, and from the rise of said surface temp. and the detection signal V indicating the curve for the temp. drop by the radiation of the sensible heat of slopping slag, the generation of slopping is detected by a detector 14. A radiation thermometer 18 for the lower part is further provided for the lower part B of the body 10, and the generation of slopping and the amt. of the slopping are detected in the detector 14 from the rise of the surface temp. in the part A, the peak value thereof, the presence or absence of the cooling curve in succession to said peak value by the cooling of the slopping slag, the presence or absence of the rise of the surface temp. in the part B by the fall of the slopping slag and the peak value thereof.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a converter slopping detection method for detecting the occurrence of slopping in a converter and the amount of slopping.

When refining steel using a converter, if slopping occurs, in which slag blows out from the top of the converter, a loss of iron content occurs. Therefore, detecting the occurrence of slopping and the amount of slopping is important in the converter. This is extremely important in managing yield. Therefore, conventionally, for example, one worker visually monitored the converter inlet or measured the surface temperature of the upper part of the converter body including the converter inlet with a radiation temperature needle or the like.
By time-integrating the output of the radiant temperature needle over 1 heat, the slopping occurrence length (j) is determined.

The amount of rubbing was detected. however,
In the former method, the judgment criteria are not absolute, and not only does it vary from person to person, but if the furnace body is covered with a hood etc. for dust collection, it becomes impossible to see it visually and the occurrence of sloping. However, in the latter case, the rise in temperature on the upper surface of the converter body due to flames ejected from the furnace mouth is also judged to be slopping, and it is not possible to accurately detect the amount of slopping. However, there is a problem in that it is not possible to detect only the occurrence of slopping.

The present invention has been made to solve the above-mentioned conventional drawbacks, and a first object of the present invention is to provide a converter slopping detection method that can reliably detect the occurrence of converter slopping.
The purpose of

A second object of the present invention is to provide a method for detecting slopping in a converter that can reliably detect the occurrence of slopping in a converter and also detect the amount of slopping.

The present invention provides a method for detecting slopping in a converter, in which the temperature rises in the upper surface temperature of the converter body including the converter mouth, and the temperature of the upper surface temperature that occurs following the rise due to cooling of the slopping slag. The first object is achieved by detecting the occurrence of slopping from the presence or absence of a decline curve.

In addition, in the same method for detecting slopping of a converter, the rise and peak value of the surface temperature of the upper part of the converter body including the converter mouth, and the cooling of the slopping slag that continues after the start-up 9 are detected. The occurrence of slopping and the occurrence of slopping can be determined from the presence or absence of the temperature drop curve of the upper surface temperature, the presence or absence of a rise in the lower surface temperature of the converter body due to the slopping slag falling from the upper surface of the converter body, and its peak value. The second objective is achieved by detecting the amount.

The present invention measures the surface temperature of the upper part of the converter body including the converter mouth with a non-contact thermometer such as a radiation temperature needle, and compares the amount of slopping with a record chart. This was done by focusing on the fact that there is no difference in the pattern of the temperature drop curve of the upper surface temperature due to cooling of the slopping slag, and the overall level of the temperature drop curve increases as the slopping increases. be. In other words, the conventional detection method of simply measuring the upper surface temperature of the converter body using a radiation thermometer and equal pressure has the problem of misjudgment due to furnace flames, etc. Therefore, in the present invention, the detection method The occurrence of slopping is detected by detecting slag attached to the body (referred to as slopping slag). If slopping occurs, slopping slag will adhere to it, so if the occurrence of slopping is detected from the presence or absence of a temperature drop curve of the upper surface temperature due to cooling of the slopping slag, it is possible to accurately detect the occurrence of slopping. It's obvious that it can be detected.

Note that the upper surface temperature of the converter furnace body can be sufficiently detected by using a conventionally used radiation thermometer. The means for measuring the upper surface temperature of the converter body is not limited to this, and any thermometer that can measure the radiant energy from the entire slopping slag can be used, and an infrared camera or the like can be used to measure the temperature. Other non-contact thermometers such as Thermopure that detect patterns can also be used.

Hereinafter, the present invention will be described in detail by taking an example in which a radiation thermometer is used.

Considering the process in which slag ejects from the converter mouth due to slopping, adheres to the furnace body, and cools down, the process in which the slag sensible heat becomes radiant energy and dissipates within a unit time dT. If the slag temperature TMC> is decreased by dT, the following relationship holds true for 9 per unit area of slag attached to the furnace body.

##T' dt--mcdT -=・=...-=
(1) Here, - is the emissivity, # is the Stefan Boltzmann constant, mFi slag weight (#7ml), and cit slag specific heat (Kcal/kli-deg).

From this, the time course of the radiant energy E of the slopping slag is as shown in the following equation.

(2) Therefore, as shown in FIG. 1, the converter opening of the converter body 10
If an upper radiation thermometer 12 is provided to detect the surface temperature of the upper part of the converter body (range A in Figure 1) including becomes.

The constants a1 and am l'i each have values expressed by the following equations.

Therefore, when the output of the upper radiation thermometer 12 is drawing the cooling curve of the slopping slag, jnV has a slope of m- with respect to 71nt, and the slopping amount becomes large (m→large, To→ (larger), the value of the output voltage V also becomes larger. FIG. 2 shows the results of comparing the correspondence between lnV and A'nt. It is clear that the mark 0 in the figure is the experimental value, and the slope almost agrees with the theoretically obtained value. or.

From this figure 2, it is clear that the peak value that indicates the amount of slopping is the value k of the output voltage 1 minute after the output rises in the thermometer measurement data, which closely matches the actual amount of slopping. It is.

Therefore, in the first invention, it is determined that slopping has occurred when the output of the upper radiation thermometer 12 shows a rise 9 and then a cooling curve due to cooling of the slopping slag appears.

That is, let the time to occur when the rise 9 occurs, and then the output jnV of the upper radiation thermometer 12 is 1 ± o, s with respect to jntK.
If a linear relationship with an inclination of is obtained, it is determined that the cooling curve is a slopping slag, and the detection device 14 detects the occurrence of slopping. In FIG. 1, it is a 16Fi hood.

In addition, in the second invention, in addition to the lower radiation thermometer 12, a lower radiation thermometer 18 for detecting the surface temperature of the lower part of the converter body (range B in FIG. 1) is provided. By lower radiation thermometer 18.

Slopping slag that has fallen from the upper surface of the furnace body is detected. By using the output of the lower radiation thermometer 18, it is possible not only to determine the occurrence of slopping more reliably, but also to confirm that the slopping is so large that the slopping slag falls below the furnace body. can be determined. In this way, by utilizing the outputs of the two radiation thermometers 12.18 placed at the upper and lower parts of the converter body 10, it is possible to detect It is possible to prevent erroneous judgments due to passage of a heating element such as a ladle passing through the lower part of the furnace body, and to detect the occurrence of slopping and the amount of slopping.

Table 1 Furthermore, the amount of slopping can be determined by detecting the value k of the output voltage 91 minutes after the output rise of the radiation thermometer measurement data when slopping occurs, and making a determination based on that value k.

The flow of detecting the occurrence of slopping and quantifying it in the present invention is shown in Figure @3.

Note that when a lower radiation thermometer is used as in the second invention, it is possible to more accurately detect the occurrence of slopping, but as in the first invention, a lower radiation thermometer is used. Of course, it is also possible to detect the occurrence of slopping using only the upper radiation temperature needle.

As explained above, according to the present invention, it is not only possible to reliably detect the occurrence of slopping, but also to quantify the amount of slopping. Therefore, the yield of the converter operation can be controlled, and the iron source yield in the converter can be controlled, which is an excellent effect.

When the inventor compared the record chart of the output of the upper radiation thermometer and the lower radiation thermometer with the occurrence of slopping in the converter, the result was as shown in Fig. 4, and it was found that slopping occurred in response to the occurrence of the blast flame at the furnace mouth. 2 without erroneously determining that lopping has occurred.
It was confirmed that only the occurrence of slopping at tL could be reliably detected. Furthermore, as shown in Table 2 below, the degree of slopping and the steel production yield 97 correspond very well to the output voltage 1 minute after the rise of the upper radiation thermometer. It was also confirmed that the yield of converter operation can be managed by determining the amount.

[Brief explanation of the drawing]

FIG. M1 is a front view including a partial block line L4, showing a state in which the upper surface temperature and lower surface temperature of the converter body are detected by the converter slopping detection method according to the present invention;
Fig. 2 is a diagram showing the relationship between the output voltage of the upper radiation temperature needle of 1 nV and the elapsed time of 1 nt after the occurrence of slopping, for detailed explanation of the present invention, and Fig. 3 is a diagram of the converter according to the present invention. FIG. 4 is a diagram showing an example of a record chart of an upper radiation thermometer and a lower radiation thermometer. 10... Converter furnace body, 12... Upper radiation thermometer. 14...Detection device, 18...Lower radiation thermometer. Agent Takaya Ron C and 1 other person) No. ! Figure 2 Figure t (min) Figure J

Claims (1)

[Claims] 0) Rise in surface temperature of the upper part of the converter body including the converter mouth;
A method for detecting slopping in a converter, the special purpose of which is to detect the occurrence of slopping from the presence or absence of a temperature drop curve of the upper surface temperature due to cooling of the slopping slag that occurs following the rise. (2) The rise and peak value of the upper surface temperature of the converter body including the converter mouth, and the presence or absence of a warm decrease curve of the upper surface temperature due to cooling of the slopping slag that occurs following the rise. , the occurrence of slopping and the amount of slopping are detected from the presence or absence of a rise in the temperature of the lower surface of the converter body due to slopping slag falling from the upper surface of the converter body and its peak value. Converter slopping detection method.