JPS5855512A - Method for judging condition of blast furnace - Google Patents

Abstract

PURPOSE:To measure quantitatively and conteniously the unfused ore dropping to a tuyere by analyzing the photographs of the race way condition before the tuyere which sends pressurized and heated blast into a blast furnace. CONSTITUTION:Heated high pressure blast is blown into a blast furnace 1 from an annular tube 2, and a race way 3 is generated before a tuyere port. A mechanical shutter 5 is placed facing opposite to the tuyere-peep hole 4 at the opposite side of the tuyere, and said shutter 5 is rotated at a predetermined speed by means of a motor 6 controlled by a device 11. When the position of slit of the shutter 5 coincides with the hole of a pinhole-plate 7, a television camera 10 operates electron scanning of the ray passing through a film 8. Consequently, while the slit passes above the hole, an afterimage is made on a pick up tube and one piece of the image is completed. The degrees of brightness are different between the cases when falling of unfused charge is not of served and falling of coke is only observed (small white particle image) and when falling of unfused charge along with coke is observed (shadow image). When this brightness is lower than the predetermined standard value, the amt. of the unfused ore is calculated on the base of the size and transparency of the dark part.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a method for determining the condition of a blast furnace that is optimal for obtaining useful information for blast furnace operation.

Generally, in a blast furnace, high-pressure hot air is forced into the furnace through the tuyeres, so a raceway and a cavity are formed in front of the mouth. It is known that there is a correlation between this raceway and the conditions inside the furnace, such as the injected hot air, the coke particle size before the raceway, and the air permeability in front of the tuyere. For example, if the raceway depth increases, this means that the air permeability in front of the tuyere deteriorates and the air volume increases, and if the raceway depth decreases slightly, it means that the temperature in front of the tuyere increases. . For this reason, knowing the condition of the raceway is extremely important.

By the way, in normal blast furnace operation, most of the ore is reduced in the so-called roots at the top of the tuyeres, and the ore is completely dissolved and drips down, causing undissolved ore to fall to the tuyeres (so-called raw precipitation).
However, if the fluctuation is large, such as in cases where the bulk zone volume is expanded and the root position is extremely lowered in order to improve gas utilization efficiency when operating at a low fuel ratio, it may result in feathering. This may occur. If the size and frequency of occurrence of the peak (main peak) is large, it may cause fluctuations in the hot metal composition, furnace cooling, etc., and cause major operational problems.

Conventionally, the degree of precipitation occurring can be determined by visually observing the sway 3 in the blast furnace from time to time through the tuyere 2 of the blast furnace 10 as shown in Figure 1, or by checking the temperature of the furnace wall using the shaft gas sampler 4. It was estimated by detecting (or detecting the Ii degree using a skin flow meter). (Note that 5 in the figure is a root, and 6 is a massive band.) However, visual observation of the tuyeres is not always possible, there is large variation among observers, and the observation location is high temperature.
There are problems because it is a dangerous place. On the other hand, the estimation based on the measurement results of the shaft gas sampler is just an estimation, and there are problems with its accuracy.

An object of the present invention is to provide a method for determining the condition of a blast furnace, which continuously quantifies the amount of unmelted ore flowing into the siding area and eliminates the above-mentioned conventional drawbacks.

The present invention focuses on the fact that when there is so-called live drunken coke, particles of different size and blackness than swirling coke fall through visual observation of the coke, and analyzes images directly taken of the condition of the coke. The best thing to do is to make it possible to continuously quantify the amount of BT injected into the tuyere. In other words, the situation inside the raceway of the blast furnace surface is photographed using a tuyere camera with a shutter, and the brightness of the video image obtained is examined for each part. Calculate the undissolved ore t given the size and brightness of
Unmelted ore tk to the tuyere is determined by integrating all images, and the furnace condition is determined based on this result.

A method for analyzing photographed images of raceway conditions will be explained below with reference to the drawings. FIG. 2 is an image in which no raw drunkenness is observed, and FIG. 3 is an image in which raw drunkenness is observed (diagonal me in the figure). Figures 2 and 3
The large circle in the screen shown in the figure indicates the shape of the tuyere at the tip, and the /JS particles within it indicate coke. Incidentally, the particle size, low brightness, and darkness of coke are not extreme and are below a certain value, but for raw ore, the particle size, low brightness, and darkness vary. It is clear from visual observation that it is clearly coke.In order to determine whether someone is drunk or not, the reference value C for the brightness on the scanning line is shown in Figure 3.
Set up a hole and take measurements. The value of the brightness Cs may be adjusted to match well with the results of human visual observation and may be changed as appropriate. Since the ore moves at high speed in the raceway, the present invention uses a mechanical shutter-equipped camera.

The method for evaluating the amount of raw precipitation per unit time is #! The brightness changes as shown in FIGS. 4 and 5.

FIG. 4 corresponds to Snoring Diagram 2, and FIG. 5 corresponds to FIG. 3. When the standard value is CI, the size of things with brightness below the nuclear standard value C1 (things with large darkness),
Considering the brightness, length and dimensions of the low brightness part,
The amount of Y is.

Y〒Σi (／ i X wii) a, s*** group 11
It is found as @(1). The value of Y is summed, for example, every 30 minutes and every 8 hours, and the 30-minute value and the 8-hour value of the amount of precipitation are tossed. In Equation (1), It is the width of the decrease in brightness p, and vyi is the length of the portion where the brightness is decreased.

An increase in the yield (i.e. an increase in the value of Y) increases the direct reduction (F, 0+C→F, +CO) in one drop. Since direct reduction is an endothermic reaction, if the raw porosity increases to an extreme extent, it will lead to a significant drop in the temperature of the hot metal, ie, furnace cooling. In this way, the amount of precipitation and furnace conditions are closely related, so the value of Y determined as described above is
A discriminant value regarding the transition is provided to determine the furnace condition. The number of discriminant values may be any number, two large and small points, that is, the discriminant value fY
, , Y, the case of binding will be specifically illustrated.

When determining the criteria for discrimination as shown in Table 1, the furnace condition can be determined from the measured Y and the discrimination values Y-, Ym as shown in Table 1112. In fact, the O judgment is made by converting the brightness into a current value and processing it into a signal in which the current value becomes larger in response to greater darkness (lower luminance). For example, the reference value CI for the brightness on the scanning line of a video image
According to the visual result, the voltage is set to 30 mA, and the scanning line LH is run at a speed of 1 second each time. Therefore, the camera shooting interval i
j every second. The dimension of Y is (mA,
W%) shall be collected every 30 minutes. This Y
Figure 6 shows the change in value, and Figure 7 shows the change in hot metal temperature. As is clear from FIGS. 6 and 7, it can be seen that the hot metal temperature is low F when the raw draft is large.

For convenience of the above analysis #'i, we have shown an example in which it was performed only on one scanning line set in the image, but this is done by calculating the unmelted ore l in the entire area of the image, and based on the integrated value, It is necessary to judge the situation.

Next, FIG. 8 shows an example of a device that executes the above analysis process.

High-pressure hot air is fed into the blast furnace 1 through an annular tube 2. This creates a raceway 3 at the tuyere of the furnace 1. On the other hand, a tuyere viewing window 4 is provided at a portion facing the tuyere, and a mechanical shutter 5 is further provided opposite to this tuyere viewing window 4. The mechanical shutter 5 is provided with a slit as shown in FIG. 9, and is rotated by a motor 6 at a predetermined rotational speed. A pinhole plate 7 is provided at a position aligned with each of the raceway 3, the tuyere viewing window 4, and the slit portion of the mechanical shutter 5. Furthermore, a filter 8 is provided opposite to the Nihinhole plate 7, and a zoo lens 9 and a television camera 10 are provided opposite to this filter 8.
is provided. Further, the television camera 1o and the motor 61/C are provided with a shutter control device fill, which synchronizes the movement of the electron beam of the camera with the timing of the mechanical shutter 5 to completely prevent screen deletion and partial display. The television camera IO includes a monitor 12 and a signal processing device 14.
are connected to each other, so that the contents captured by the television camera 1o are displayed and the signals are typed by the typewriter 15. Furthermore, a video tape recorder 13 is connected to the monitor 12, and it is convenient to transport the tape and introduce J1 when keeping records and watching the coke swirl in the raceway.

The pinhole plate 7 is provided to make the screen of the television camera 10 clear. In other words, without the pinhole plate 7, light would enter the camera regardless of the position of the slit, but by providing the pinhole plate 7, light would enter the camera only when the slit and pinhole positions coincided. Allows light to enter and provides an accurate shutter function.

The light that has passed through the pinhole plate 7 has an extremely high intensity because the tuyere portion is extremely hot (approximately 2000° C.).

Therefore, a filter 8 is provided to reduce the light entering the camera. Light attenuation must be carried out not only for light of a specific wavelength but for all wavelengths, and for example, an optical filter of about ND8 can be applied.

The operation of the above configuration will be explained as follows. The shutter control device 11 rotates the motor 6 to achieve a predetermined shutter speed.

At the same time, when the slit m-bt of the mechanical shutter 5 and the hole of the hole plate 7 match, the television camera 10
starts electronic scanning. As a result, an afterimage is formed on the image pickup tube while the slit portion passes over the hole.

Before this afterimage disappears, one frame's worth of electronic scanning is performed, so that one frame's worth of image is completed. In other words, the image is obtained using a method similar to strobe photography. In this case, the image frame aq shutter control device fj111 can be used as a controller. That is, the mechanical shutter 5 is rotated at a constant speed, and the TV camera 1 is synchronized with the slit of the mechanical shutter 5 at regular intervals.
The signal processing device 14 performs the furnace condition judgment processing shown in Table 2 based on the setting values in Table 1 described above, and outputs the typewriter 15KF as the output device.
Print out the status judgment results.

In the apparatus shown in Fig. 8, we have described the case where the furnace condition is determined based on the obtained image signal, but when the signal processing device 14IC microcomputer III is used, the furnace condition is further determined based on the result of the furnace condition determination. Internal temperature control is possible. This control is shown as a flowchart in the first side of Example 1.

As is clear from Figures 6 and 7, a drop in hot metal temperature occurs at the edge of a decrease in Y value, so a graph using a regression equation as shown in Figure 11 was created in advance based on operational data from a few days ago. I'll keep it. When creating, for example, 11°f as shown in Figure 6.
For the hot metal temperature (HMT) of , it is made to correspond to the Y value of 1 hour before. For example, in the case of Figure @10, which has two types of standards, the temperature setting value Tc (for example, 1480°C) is set in advance.
Necessary control is performed based on the deviation of Y from the Y set value YC corresponding to the temperature set value Td (for example, 1460° C.) and the Y set value Yd corresponding to the temperature set value Td (for example, 1460° C.).

As shown in FIG. 1θ, when Y is smaller than Yc in step 31, Kintei m is finished without executing the new Kei process, but when it exceeds YcYr, the process proceeds to step 32 and it is determined whether Yd has been reached. . That is, Yc-Yd
If KY exists between then, the degree of blast furnace ventilation is increased in step 33, and in a region where Y exceeds Yd, the process proceeds to step 34, where ore 't is decreased by 1 ton. In step 33,
At step 32, ΔHMT= (Y-Yc) −
Since the temperature decreases by an amount A than Tc, processing is performed to increase the blowing temperature in order to increase ΔHMT. For example, in response to a decrease in HMTL:DI O'C, the air blowing temperature is increased by t-15°C.

In the above configuration, an example was shown in which a camera with a shutter was placed only in one of the plurality of tuyeres, but it is desirable to place a camera in each tuyere. Although only one scanning line LH is illustrated, a plurality of scanning lines LH may be used, and the scanning line LH may be arranged in a direction other than one horizontal direction.

As is clear from the above, according to the present invention, by analyzing photographed images of the tuyere, it is possible to continuously quantify the intoxication of the tuyere.

[Brief explanation of drawings]

FIG. 1 is an explanatory diagram showing the principle of conventional furnace condition estimation, FIG. 2 is an image diagram when no drunkenness occurs according to the present invention, and FIG. 3 is an image diagram when a large amount of living occurs according to the invention. FIG. 4 is an explanatory diagram of the evaluation according to the present invention when there is no occurrence of raw drunkenness, FIG. is a hot metal temperature characteristic diagram according to the present invention, FIG. 8 is a configuration diagram showing an embodiment of the present invention, FIG. 9 is a perspective view showing a part of the shutter of the embodiment of FIG. 8, and FIG. A flowchart showing an example of applied processing, and FIG. 11 is an explanatory diagram of setting values related to the processing of FIG. 10. 1...Blast furnace, 3...Raceway, 4...
Tuyere peephole, 5.. Mechanical shutter, 611.
··motor. 7. Excellent: Pinhole plate, 8: Filter, 10.
...TV camera, 11.. e. Shutter control device, 12.. Monitor, 14.. Signal processing device. 15...Typewriter-0 Agent Tatsu Unuma (and 2 others) IV Figure 2 Figure 3 Figure 6 Figure 7 Figure 7 1Q N l:P,ll M Y Yd Y-

Claims (1)

[Claims] (1) In a method for determining the furnace condition of a blast furnace in which a clay pipe that blows high-pressure hot air into the furnace from the siding is provided with a tuyere viewing window for monitoring the raceway in the furnace, a photographed image of the raceway is When the brightness and brightness of each required area of the generated image is lower than the preset standard value, the amount of undissolved ore is calculated based on the size and brightness of the dark part of the area, and the amount of undissolved ore is calculated based on the calculated value. A method for determining the condition of a blast furnace, characterized by determining the condition of the furnace based on the following criteria.