JPH0379405B2 - - Google Patents

Description

[Detailed description of the invention]

INDUSTRIAL APPLICATION The present invention relates to a method useful for operating a converter, in particular:
This invention relates to a method for detecting the occurrence of slopping, which is a major hindrance to operations. Prior Art The refining of hot metal and molten steel in a converter involves blowing pure oxygen gas onto the molten metal from a lance inserted into the furnace from the converter mouth, stirring the molten metal, and decarburizing it. Dephosphorization and desulfurization are performed by the reaction with the molten slag that is formed into sludge by the sludge agent introduced into the sludge, but during this sludge formation process, the slag composition, viscosity,
Slag forms depending on various conditions such as the amount of oxygen in the slag, and if this progresses excessively, so-called slopping may occur in which slag and even molten metal overflow from the furnace mouth. When this slopping occurs, it has a major impact on the molten steel composition, steel production yield, etc., and also causes various problems such as a decrease in work efficiency, a decrease in the calories of the recovered gas, a deterioration of the work environment such as the generation of red smoke, and damage to equipment. cause
Therefore, it is necessary to suppress the occurrence of sloping as much as possible. Therefore, it is possible to quickly predict the situation inside the converter furnace,
It is necessary to operate the converter appropriately, such as by preventing the occurrence of slopping, and various proposals have been made to understand the condition of the converter. Specifically, JP-A-52-101618 discloses a method for estimating the amount of oxides produced in the furnace, that is, slag, by calculating the oxygen balance based on exhaust gas information during blowing in the converter steel manufacturing process. ing. In this method, a time delay due to analysis is unavoidable, and since the cause of slopping is not solely due to the amount of slag, the accuracy of predicting the occurrence of sloping is low. Various attempts have also been made to detect the slag level using physical measurement methods, including the acoustic measurement method (Japanese Patent Application Laid-Open No. 54-33790) and the vibration measurement method (Japanese Patent Application Laid-open No. 33790/1989).
No. 54-114414), Furnace Pressure Measurement Method (Unexamined Japanese Patent Publication No. 1983-
104417), microwave measurement method (Unexamined Japanese Patent Publication No. 104417),
140812), Furnace Surface Temperature Measuring Method (Unexamined Japanese Patent Publication No. 1983-
48615) have been proposed. The acoustic measurement method attempts to predict the occurrence of sloping by estimating the slag level by ascertaining changes in the frequency and intensity of the sound generated from inside the furnace during blowing, while the vibration measurement method attempts to predict the occurrence of slopping. This method attempts to predict the occurrence of slopping by estimating the slag level or state by understanding vibration changes and waveform transitions, while the furnace pressure measurement method attempts to predict the occurrence of slopping by understanding changes in the furnace exhaust gas injection pressure during blowing. This method attempts to predict the occurrence of slopping, and the microwave measurement method involves directly projecting microwaves into the furnace during blowing.
This method uses the principle of FM radar to directly measure the slag level and predict the occurrence of slopping.The furnace surface temperature measurement method captures the radiant energy at the top and bottom of the furnace body as temperature, and measures temperature changes and peaks. It attempts to detect the occurrence and amount of sloping from values etc. The acoustic measurement method, vibration measurement method, furnace pressure measurement method, and furnace body surface temperature measurement method described above are all indirect measurement methods, and cannot quantitatively grasp the slag level and slag condition, so they are difficult to detect due to slopping. Prediction accuracy is low. The microwave measurement method can directly measure the slag level, but since the molten metal, slag, gas, etc. move in an extremely complex manner inside the converter during blowing, it is difficult to detect or estimate abnormalities. This is not easy, and requires advanced technology for signal processing, etc., so it is inevitable that the equipment will be expensive. In response to these problems, the applicant first installed an in-furnace light measuring device into a through hole provided in the non-immersed part of the converter wall, and observed the intensity and/or wavelength changes of the in-furnace light and followed up. A patent application has been filed (Japanese Patent Laid-Open No. 58-37872) for a method of detecting the slopping level and detecting slopping and poor sludge formation. It took operational action. OBJECTS OF THE INVENTION An object of the present invention is to provide an excellent slopping detection method that fundamentally solves the problems of the prior art. Structure and operation of the invention The structure of the present invention is such that a photodetector is placed in front of a through hole provided in the side wall of the converter body, and the proportion of yellowish colors and fluctuations in that proportion are detected from the obtained color signals. This converter sloping detection method is characterized in that the occurrence of sloping is detected by extracting the color and comparing it with a predetermined color reference. As a result of various studies on methods for detecting the occurrence of slopping, the present inventor found that the gas atmosphere and slag in the converter during operation each emit light of a characteristic wavelength and intensity. is high temperature, wide wavelength range, and high intensity light.
This is based on the fact that while slag emits white light in terms of color, slag is lower in temperature than the gas atmosphere, lacks a short wavelength range, and has a lower intensity, emitting yellowish light in terms of color. , the ever-changing situation inside the furnace,
This method has been completed to detect the occurrence of sloping by inputting light as light using a direct light receiving device and processing and analyzing the image of the field of view of the light receiving surface over time. When slag formation progresses to some extent in the converter during operation as described above and the temperature of the gas above the slag becomes higher than the temperature of the slag, the relationship between the wavelength and intensity of light emitted by the gas and slag is shown in Figure 1. This shows a clear difference. Therefore, when observing with an observation device with a circular light-receiving surface facing the hole 4 that is provided in the furnace wall and passing through the furnace wall, it is found that the amount of slag formation is relatively small in the early stage of blowing, as shown in Figure 2. In this case, the field of view is covered with white light emitted by the hot gas atmosphere 18, as shown in FIG. 2'. As the slag formation further progresses and the amount of slag 16 increases as shown in Figure 2, the surface of the slag is generated by the oxygen ejected from the lance 19 and the blowing reaction.
The slag in an emulsion state, which is agitated by CO gas and the like and whose temperature is lower than the upper gas atmosphere, is captured in the field of view of the light receiving surface as a colored wave shape, as shown in Figure 2', and constantly fluctuates. When the slag in the emulsion state causes so-called slopping and overflows out of the furnace as shown in FIG. 2, the entire field of view of the light receiving surface takes on a yellowish color as shown in FIG. 2'. However, for the occurrence of sloping, Fig. 2'
Based on the assumption that the proportion of colored parts in the field of view corresponding to
As a result of a detailed study of the relationship between the quantitative proportions of these separated colors and the degree of their change and the occurrence of sloping, we found that yellowish colors are the best, and that there is a correlation. The method and results will be described below. First, a through hole 4 for observation that penetrates into the furnace is provided in the side wall of the converter body. A photodetection device 6 for observing light inside the furnace is placed in front of this through hole. Therefore, this through hole may be a tapping hole. As shown in FIG. 3, the photodetecting device 6 is composed of a photoconductor probe 7 containing a photoconductor, a conversion connector 9 connected to the photoconductor, and a photoelectric conversion element 10. A light guide is a conductor, such as a quartz-based optical fiber, that transmits synchrotron radiation emitted from a high-temperature object with low loss. However, since the light guide probe 7 containing a built-in light guide is inserted into the through hole 4 that opens into the high-temperature converter, there is a risk of wear and tear. It is desirable to do so. A photoelectric conversion element has a function of converting light into an electric signal for each wavelength in proportion to its intensity, and is, for example, an ITV camera, a photomultiplier tube combined with a spectrometer, or the like. This is at a sufficient distance from the receiving surface of the light guide under severe conditions, so that
It is in a favorable environment where it can perform its functions. With the photodetector 6 configured as described above, the light inside the furnace is detected at the tip of the photoconductor, and the image of the light passes through the conversion connector 9 and the photoelectric conversion element 10, and becomes a photoelectric conversion image signal 41 in the wavelength range. It is sent to the sorting device 11. Here, the entire wavelength range of the light inside the furnace is B (blue), G (green),
R (red) and video signals for each wavelength range (R/
G/B signal) 42, and the binarization circuit 51
The light is then sent to the area calculation device 12, where the proportion of each color to the total light reception input for a certain short period of time is calculated.
This process will be explained using diagrams. FIG. 4 shows an example of a pattern of short-time changes in the light input inside the furnace, which is photoelectrically converted and passed through the wavelength range separation device 11 into a B signal for each wavelength range, that is, a wavelength range of about 0.3 to 0.4 microns, and a wavelength range of about 0.4 microns. The signals are divided into a G signal of ~0.6 microns and an R signal of wavelength range of approximately 0.6 to 0.8 microns, and are expressed as an analog R signal 21, an analog G signal 22, and an analog B signal 23, respectively. In order to convert these into binary values, a threshold level of 24 is set for the R signal, a threshold level of 25 is set for the G signal, and a threshold level of 26 is set for the B signal. conversion circuit 5
1, signals represented by convex lines 27, 28, and 29 in FIG. 5 are obtained, and from these, B, G, and R
As shown in the subdivisions of the color-coded line 30 as an overall signal, it can be seen that the subdivisions change from red to magenta, red, yellow, and red over time. Calculated as area percentage. In this example, only three colors, red, magenta, and yellow, happened to appear, but from the B, G, and R signals, there is a possibility that a total of seven types of colors, eight types including black, may appear. The calculation of the area ratio for each color is performed by the area calculation device 12. For example, if the reset pulse is 16.7 msec,
The count pulse is set to 0.134 μcec (7 MHz), the above-mentioned binary R signal, binary G signal, and binary B signal are placed, and it is calculated from the AND of the pulse between one reset pulse and the binary signal. . For example, for yellow, by counting the number of R.G on and B off pulses, the area ratio of yellow to the total image area during 16.7 msec can be obtained. The area ratio signals for each color obtained in this way are divided into two systems, and one system is further passed through a binarization circuit to extract the size of the area ratio itself as a binary signal, and the other system is used to transmit high-frequency signals. filter,
After passing through a positive value converting circuit, it passes through a binarizing circuit and is extracted as a binary signal that emphasizes the change in area ratio. In order to examine the correlation between these two color-based binary signals and the possibility of slopping occurring, we investigated the
A through hole was provided in the side wall of the furnace body with a height of m, and a test was conducted with a photodetection device facing, and the results shown in Tables 1 and 2 were obtained. If we examine this in detail, we will find that there will be almost no errors even if we extract only the binary signal related to the yellow area in Table 1, which is the result of the combination of the two colors red and yellow, and make a judgment. Ru. Similarly, in Table 2, which shows the results of the combination of two colors, white and yellow, it is considered that there will be almost no error even if only the binary signal related to the yellow area is taken out and judged.

【table】

[Table] From the above considerations, the occurrence of slopping can be detected by selecting from the color signals obtained by the photodetector described above.
It was concluded that the occurrence of sloping could be detected using the criteria shown in Table 3, mainly by extracting the proportion occupied by yellowish colors and the degree of change in that proportion. Here, the term yellow color refers to the aforementioned wavelength range of approximately 0.4 to 0.6 microns, which is perceived as yellow to the human eye, and is around the monochromatic wavelength of yellow in physics, 579 microns.

[Table] However, in reality, it is necessary to consider the operational status of the converter at the time of judgment. For example, in the early stages of blowing, the gas temperature inside the furnace is low, so the light inside the furnace is biased toward yellowish colors, and the input of ore, the addition of auxiliary materials, the amount of silicon in the hot metal, etc. are also factors that cause the light inside the furnace to change, so information on these is also necessary. It is. A block diagram of the method of the present invention including these is summarized in FIG. Next, the attachment of the photodetector used in the method of the present invention to the side wall of the furnace body will be described. Not only when the attachment point is a tapping hole, but also when a through hole is provided in a part that is not immersed in molten metal during furnace swinging or tapping, it can be removed from the hole during times when observation inside the furnace is not actually required. It is desirable that the equipment be away from high temperatures and dusty environments. An example is shown in FIG. The light guide probe 7 is attached to a movable pedestal 63 that straddles a rail 62 attached to a pedestal 61, and can be inserted into and removed from the through hole by a hydraulically operated cylinder 64. In this case, as shown in FIG. 7I, the optical guide 7, the conversion connector 9, and the photoelectric conversion element 10 are integrated, and a flexible cable 71 is used to connect this to the wavelength range separation device 11 to absorb displacement. , as shown in Figure 7,
One possible method is to utilize the flexibility of the light guide to absorb displacement and use a fixed cable 72 between the photoelectric conversion element 10 and the wavelength range separation device 11, but it is better to transmit the light with the light guide. The method shown in FIG. 7 is preferable because the attenuation is greater than when sending electrical signals through cables. Example: A through hole is provided in the side wall of the furnace zone at a height of approximately 4 m from the furnace bottom of a 170 t/CH top-bottom blowing converter, and a photodetection device is exposed, and the entire device is constructed as shown in the overall block diagram of Fig. 3. After assembling and operating the system, the possibility of slopping was judged according to the criteria in Table 3, and the results in Table 4 were obtained. The molten pig iron at this time has a [Si] content of 0.30~
It is 0.50%.

[Table] When an alarm is issued by the sloping detection device, it is not realistic to continue operation until the occurrence of sloping is actually confirmed. This judgment was made by also implementing slopping suppression actions. Effects of the Invention As detailed above, the sloping detection method of the present invention has a high sloping detection rate and can thereby effectively suppress sloping, so it is extremely valuable in terms of converter operation.

[Brief explanation of drawings]

Figure 1 is a diagram showing the relationship between the wavelength and intensity of light emitted by the slag and the gas above the slag, Figure 2 is an explanatory diagram showing the furnace conditions and an image of the light receiving surface, Figure 3 is an overall block diagram, and Figure 4 is an analog signal diagram of the in-furnace light by wavelength,
FIG. 5 is a binary signal diagram of the light in the furnace by wavelength, FIG. 6 is a diagram showing the moving device, and FIG. 7 is an explanatory diagram of the flexible part. DESCRIPTION OF SYMBOLS 1...Converter, 4...Through hole, 6...Photodetector, 7...Photoconductor probe, 9...Conversion connector, 10...Photoelectric conversion element, 11...Wavelength range separation device, 12... Area calculating device, 13... Judgment circuit, 16... Slag, 17... Molten metal, 18... High temperature gas atmosphere, 19... Lance, 21... Analog R signal, 22... Analog G signal, 23... Analog B signal, 24...R signal threshold level, 25...G signal threshold level, 26...
...B signal threshold level, 27...Binarization R
Signal, 28... Binarized G signal, 29... Binarized B
Signal, 30...Colored line, 41...Photoelectric conversion video signal, 42...Video signal for each wavelength range, 43...Yellow area ratio signal, 44...Yellow area ratio binary signal, 45...Yellow area ratio change degree binary signal,
46...Signals for blowing, ore injection, auxiliary material injection, hot metal silicon amount, etc., 47...Slopping detection signal,
51... Binarization circuit, 52... High frequency transmission filter, 53... Positive value conversion circuit, 54... Binarization circuit,
55... Binarization circuit, 56... Converter process information, 61... Frame, 62... Rail, 63... Movable frame, 64... Cylinder, 71... Flexible cable, 72... Fixed cable.

Claims (1)

[Claims] 1. A light detection device is placed facing the through hole provided in the side wall of the converter body, and the proportion of yellowish colors and the fluctuations in that proportion are extracted from the obtained color signal,
A method for detecting sloping in a converter, characterized by detecting the occurrence of sloping by comparing it with a color standard determined in advance.