JPS6224485B2 - - Google Patents

Description

[Detailed description of the invention]

INDUSTRIAL APPLICATION FIELD The present invention relates to a method of operating a closed converter, and more particularly, to a method of operating a closed converter, in which slopping is detected and the close contact between the furnace opening and the exhaust gas hood is released. Purpose of the invention In heat calculation during converter operation, the ratio of sensible heat of the exhaust gas discharged from the furnace mouth to the total heat output is relatively large, and when the calorific value of CO gas in the exhaust gas is also taken into account, the total amount of heat is enormous. . Therefore, its recovery is essential for improving energy consumption. There are two main recovery methods: one is to burn the exhaust gas and recover the sensible heat of the exhaust gas and the combustion heat of CO in a boiler, and the other is to introduce as little air as possible into the exhaust gas. The idea is to only partially combust the CO, recover the majority of the unburned CO, and use it as a CO-containing gas as a fuel or chemical raw material. In the method of recovering unburned gas, in order to prevent air from being mixed in the exhaust gas as much as possible, main materials such as hot metal or scrap are charged into the converter, or the furnace must be opened when tapping steel. The opening and the lower end of the skirt at the bottom of the exhaust gas hood, which is the exhaust gas suction end of the exhaust gas duct, are in partial or full contact with each other, so that the gap between them can be minimized over the entire circumference of the converter opening. A closed converter must be used. In closed converter operation, as mentioned above, although it is suitable for exhaust gas recovery, it is necessary to quickly release the close contact when slopping occurs. If slopping occurs, not only will the amount of gas to be recovered decrease and the gas composition fluctuate, but also the high temperature molten material with a large heat capacity will be ejected from the furnace mouth, which will be described later. If the molten material comes into contact with the skirt part of the exhaust gas hood that seals between the mouth and the duct and has a water-cooled pipe, this part will be damaged, and furthermore, if the water-cooled pipe is damaged and water spews out,
There is also the risk of a steam explosion resulting in a major accident. Furthermore, if the contents of the furnace are fused to the seal, it becomes impossible to separate the furnace from the hood, and the furnace body cannot be tilted, making it impossible to tap steel, which poses a serious operational problem. Therefore, when operating a closed converter, a method must be taken to detect slopping in the furnace and quickly release the close contact between the furnace opening and the exhaust gas hood.
The present invention provides this method. Structure and operation of the invention The structure of the present invention is a closed converter operating method in which the converter mouth and the exhaust gas hood are brought into close contact with each other, in which a photodetection device is disposed in a through hole provided in the side wall of the converter,
This closed type converter operating method is characterized in that in-furnace slopping is detected from an in-furnace light detection signal from the photodetector, and the close contact between the converter mouth and the exhaust gas hood is released. A particularly important point in this method is the detection of in-furnace sloping using the photodetection signal from the photodetector, so this will be explained in detail first. In the present invention, the photodetection device refers to a series of devices that receive furnace light, photoelectrically convert it, perform arithmetic processing, and output a photodetection signal. An example of a block diagram thereof is shown in FIG. Each element and its function will be explained below. In FIG. 1, a light guide probe 7 containing a built-in light guide is inserted into a through hole penetrating the converter side wall and receives the furnace light at its tip. Like an optical fiber, the radiation emitted from a high-temperature object is transmitted to the other end using a conductor that transmits it with low loss. Since the tip of a light guide probe is exposed to a high temperature and dusty environment, some means of protecting the light guide, such as a double tube structure with an observation window at the tip and protection by flowing purge gas, is required. Make it. The end of the light guide is connected to a photoelectric conversion element 9 via a conversion connector 8 . A photoelectric conversion element is a device that photoelectrically converts images transmitted from a photoconductor.
ITV cameras are one example. The light image captured at the tip of the light guide becomes a photoelectric conversion image signal 10 and is sent to a wavelength range separation device 11. Here, the light inside the furnace covers the entire wavelength range of B (blue) and G.
(green) and R (red) and output as video signals (R, G, B signals) 12 for each wavelength range, sent to the area calculation device 14 via the binarization circuit 13, and then The proportion of each color to the total received light input is calculated. For example, the R signal, G signal, and B signal binarized by the binarization circuit 13 are counted with a pulse of 0.134 μsec.
(7MHz), count the number of R, Gon, and Boff pulses from the signal between reset pulses of 16.7 msec, pulse x binary signal, and get 16.7 msec.
The area ratio of the yellowish color during sec is calculated and output as the yellowish area ratio signal 15. The reason why the area ratio of yellowish color is specifically illustrated here is that the proportion of yellowish color in the light inside the furnace is closely related to the waxing and waning of the slag, and by detecting this waxing and waning, it is possible to predict sloping and This is because it has already been discovered that it can be detected.
The present applicant has previously filed a patent application and disclosed this. The photodetection signal 15 from the photodetector thus obtained is sent to the area ratio display device 24 and displayed. FIG. 2 schematically shows this example over time. In the figure, S ₀ is the early stage of blowing, where the furnace temperature is low and the yellow area ratio is high. S ₁ is a signal considered to have a possibility of sloping. Next, a specific example of a method for detecting sloping and applying it to release the exhaust gas hood will be described. Photodetection signal 15 obtained from the aforementioned photodetection device
is further divided into two systems as shown in FIG.
It is extracted as a binary signal 17 of the area ratio and inputted to the determination circuit 22. The other system passes through a high-pass filter 18 and a positive value converting circuit 19 and enters a binarizing circuit 20, where it is taken out as a binary signal 21 representing the amount of change in area ratio and input to a determining circuit 22. The determination circuit 22 uses a combination of these two binary signals to determine the possibility of slopping, as shown in Table 1, for example.

[Table] If this judgment is positive, the output signal 23 from the judgment circuit is released from the exhaust gas hood. (not shown) to raise the cylinder and release the close contact between the furnace mouth and the exhaust gas hood. FIG. 4 is a schematic diagram of a seal portion for explaining the close contact and release of the exhaust gas hood and the furnace mouth.
The exhaust gas hood 31 is surrounded by a sliding skirt 32, and a water-cooled seal ring 33 at the lower end is in contact with the entire circumference of the converter mouth fitting 37 to minimize the gap therebetween. The skirt is cooled with water pipes to withstand high heat. A seal jacket 34 is provided on the outside of the skirt 32.
is surrounded by a skirt 32 and a seal jacket 34.
are raised and lowered together by the skirt raising and lowering cylinder 35. A seal plate 36 is attached to the exhaust gas hood so as to surround the outer periphery of the exhaust gas hood, and the seal plate 36 is attached to the seal jacket 34.
It is immersed in a liquid filled with water. Therefore, between the furnace mouth 30 and the exhaust gas hood 31, the skirt 32 and the seal plate 36 were sealed by the liquid in the seal jacket, and when the skirt 32 was raised by the cylinder 35, the above-mentioned seal was maintained. The contact between the water-cooled seal ring 33 and the furnace mouth metal fitting 37 is broken, and the seal is released. Next, this method will be explained with examples. Example Blowing was carried out by charging molten metal to a height of 1.5 m from the bottom of the furnace in a 170T top-bottom blowing sealed converter with a furnace height of 8 m. A through hole was made in the converter wall at a vertical distance of 2.5 m below the furnace mouth, and the photoconductor probe of the aforementioned photodetection device was inserted. , depending on the area ratio of the yellowish color mentioned above. An area ratio of 100% means that the slag level is above the through hole, an area ratio of 50% means that the slag level is the center of the optical fiber field of view, and an area ratio of 0% means that the slag level is less than the through hole. However, the threshold level used in the binarization circuit 13 for calculating the area ratio is the R signal 35
%, G signal 35%, B signal 25%. In the circuit for slopping judgment (Fig. 3), the cutoff frequency of the high-pass filter 18 is 5 Hz, the threshold levels for the binarization circuits 20 and 16 are both 50%, and the judgment is made as described above. Based on Table 1 of Approximately 12 minutes after blowing, a signal indicating the possibility of slopping was issued, and the hydraulic switching valve control device was immediately activated to raise the skirt and release the seal. Although slag overflow from the furnace mouth due to slopping was observed, there was no damage to the equipment. Effects of the Invention As detailed above, the present method allows slopping in the furnace to be detected reliably, so that the sealing of the converter can be quickly released. Therefore, closed converter operation can be carried out safely and reliably, and the value of this method is extremely large.

[Brief explanation of the drawing]

Figure 1 is a block diagram of the photodetector, Figure 2 is a schematic diagram of the in-furnace light detection signal, Figure 3 is a block diagram of the circuit for determining slopping, and Figure 4 is the connection between the furnace mouth and the exhaust gas hood. It is an explanatory view showing a seal part. 7... Light conductor probe, 8... Conversion connector,
9... Photoelectric conversion element, 10... Photoelectric conversion video signal, 11... Wavelength range separation device, 12... Video signal for each wavelength range, 13... Binarization circuit, 14... Area calculation circuit, 15... ...Photodetection signal, 16...Binarization circuit, 17...Binarization signal of area ratio, 18...High-pass transmission filter, 19...Positive value conversion circuit, 20...
... Binarization circuit, 21 ... Binarization signal of the amount of change in area ratio, 22 ... Judgment circuit, 23 ... Judgment signal, 3
0...Furnace mouth, 31...Exhaust gas hood, 32...Skirt, 33...Water-cooled seal ring, 34...Seal jacket, 35...Skirt lifting cylinder, 36...Seal plate, 37...Furnace mouth hardware.

Claims (1)

[Claims] 1 In a closed converter operating method in which the converter mouth and exhaust gas hood are brought into close contact, a light detection device is provided in a through hole provided in the side wall of the converter, and an in-furnace light detection signal from the light detection device is detected. A method for operating a closed converter furnace, characterized in that slopping in the furnace is detected and the close contact between the converter mouth and the exhaust gas hood is released.