JPS60245711A - Operating method of hermetic converter - Google Patents

Abstract

PURPOSE:To eliminate the need for lifting of a waste gas hood and to recover efficiently unburned gas by using a photodetector in place of the conventional visual observation to check the firing of the CO generated in a converter in the stage of starting blowing. CONSTITUTION:The waste gas hood 2 is moved upward and after a molten iron and scrap are inserted into the converter 1, the hood 2 is lowered to close hermetically the converter 1. A lance 11 is thereupon lowered and blowing is started when feeding of oxygen is started but a probe 81 for photodetection in the converter is preliminarily inserted into the through-hole 7 provided to the side wall of the converter 1. The firing is checked by a signal processing unit 9 after the start of blowing and a sequence control device for a waste gas recovery system is operated by the output signal thereof, by which the succeeding operation is started. The CO generated in the furnace is then perfectly burned with O2 in the air sucked through the hole 4. The inside of a recovering duct 3 is replaced by the inert gas formed by the combustion. The gate 5 is closed and a damper 12 is opened to recover the gas generated in the converter in the unburned state after the completion of the replacement is checked by gas analysis.

Description

DETAILED DESCRIPTION OF THE INVENTION Field of Industrial Application The present invention relates to a method for recovering unburned exhaust gas from a closed converter in which the converter mouth and exhaust gas hood are brought into close contact with each other.

Purpose of the Invention In heat calculation during converter operation, the proportion of the total heat output of the exhaust gas discharged from the furnace mouth 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, in order to effectively utilize the energy contained in exhaust gas, two methods are generally used. One is a method in which air is sucked into an exhaust gas recovery duct using combustion type gas processing equipment, the exhaust gas is combusted, and the obvious exhaust gas and combustion heat is recovered by a boiler.The other method is a non-combustion type gas treatment method. The equipment introduces a small or very small amount of air between the exhaust gas hood and the furnace mouth to only partially burn CO, and recovers most of the unburned GO.
It is intended to be used as an O-containing gas as a fuel or chemical raw material.

In the latter method, that is, the method of recovering unburned gas,
Before the start of blowing, the exhaust gas recovery duct is filled with air, and when the exhaust gas containing high concentration GO is introduced into the duct after the start of blowing, the gas composition in the duct enters the explosive range and becomes extremely dangerous. Therefore, immediately after blowing, the combustion state of blowing oxygen and GO generated in the furnace is checked, and then CO is removed from the system using oxygen in the air sucked in from outside the system, for example between the furnace mouth and the exhaust gas hood. The inside of the recovery system is replaced by the CO7 produced by combustion and the residual N2 in the air, and then air suction is shut off to recover high-concentration GO dregs.

Therefore, at the start of blowing, the ignition phenomenon of CO generated in the furnace can be visually confirmed without placing it in close contact with the furnace mouth where the exhaust gas foot is located, and then the combustion generated gas of the furnace exhaust gas with air can be used to
After confirming through gas analysis that the air in the exhaust gas recovery duct had been replaced, an operating method was adopted in which the exhaust gas hood was placed in close contact with the furnace mouth.

The present invention provides a method in which blowing can be started with the exhaust gas hood and the converter mouth in close contact with each other, and the subsequent sequence can proceed, thereby eliminating the need for unnecessary operations such as raising and lowering the exhaust gas hood. By keeping the converter-exhaust gas system in an electrically closed state after the start of blowing, it is possible to efficiently recover unburned exhaust gas, and it is also possible to prevent gas from blowing out of the system, reducing pollution. It is also an extremely effective method in terms of safety measures.

Structure and Function of the Invention The structure of the present invention is a closed converter operation method in which the converter mouth and the exhaust slag hood are brought into close contact with each other, and a photodetector is disposed in a through hole provided in the side wall of the converter. This is a closed converter operating method characterized by detecting ignition from an in-furnace light detection signal from a detection device and proceeding with a blowing sequence (operation).

In the present invention, a closed converter refers to a converter in which the lower end of the skirt at the bottom of the exhaust gas hood and the converter mouthpiece are in partial or full contact with each other, and the gap between them is minimized over the entire circumference of the converter mouth. Refers to a converter with a water-cooling structure.

However, as mentioned above, in closed converter operation, GO ignition is detected by the in-furnace light detection signal from the photodetector, instead of conventionally visual confirmation of GO ignition. The in-furnace light detection signal by the apparatus and the light detection device will be explained.

In the present invention, the photodetection device is a device equipped with an in-furnace photodetection probe 81, a photoelectric conversion device 82, and a signal processing device 9 shown in FIG.

The in-furnace optical detection probe 81 has a built-in conductor, that is, a light guide, which transmits the radiation emitted from a high-temperature object with low loss, such as a quartz-based optical fiber, and has some means for cooling and protecting the light guide. For example, it has a double pipe structure for cooling with fluid.

Therefore, the tip of the probe is located in the through hole 7 provided in the side wall of the furnace body.
Since it is inserted into the hole and receives light, it is exposed to a harsh environment with high temperatures and dust, so it is equipped with a sliding device so that it can be inserted and removed from the through hole at any time other than when viewing M1. is preferred.

A photoelectric conversion device is a device that photoelectrically converts an optical image transmitted by a light guide, and is an example of an ITV camera.

The photoelectrically converted video signal is sent to the signal processing device 9. The signal processing device has a series of circuits that photoelectrically converts the intensity of the light inside the furnace, binarizes the waveform sent as a video signal at an appropriate threshold level, and holds the peak to determine continuity. Its block diagram and signal processing are shown in FIGS. 2 and 3.

Taking the case where the charging conversion device is an ITV as an example, the photoelectric conversion signal output from the ITV increases in video signal in proportion to the intensity of light within the furnace light. One such model is shown in Figure 3 (
A), which is obtained as an output signal of the photoelectric conversion device 82 in the block diagram. When the signal is binarized at a threshold level set in advance by the binarization circuit 13, a signal as shown in FIG. 3(B) is obtained. When an rHJ level signal is generated here, the rHJ level is held in the peak hold circuit 14, and if it is reset by the vertical synchronization signal from the synchronization separation circuit 16, the output from the peak hold circuit 14 is as shown in FIG. The signal will be as shown in C). Therefore, each screen (
Whether or not an "H" level signal is generated in the vertical synchronizing signal can be detected by sampling in synchronization with the vertical synchronizing signal. Whether or not the rH'' level signal continues for a predetermined number of times is determined by passing it through the continuity determining circuit 15.

With such a signal processing device, "H" is detected at the time of ignition.
If the threshold level is set so that a signal of 100% level is generated and the continuity determination circuit is used to determine the ignition, detection of ignition will be extremely reliable.

Next, the operating method of the present invention will be specifically explained.

When charging hot metal and scrap, which are the main raw materials, into the furnace of the converter 1, the exhaust gas hood 2 shown in Fig. 1 is raised, and after charging is completed, the exhaust gas hood is lowered and the skirt portion at the lower end of the hood and the Bring it into contact with the furnace mouth fitting to create a sealed state.

In this state, the blowing oxygen supply lance 11 is lowered and the blowing process starts, but before this, the slide gate 5 for sucking air from outside the system is opened, and the in-furnace optical detection probe 81 is opened. is inserted into the through hole 7.

After the start of blowing, the ignition phenomenon is confirmed by the signal processing 9 described above, and the output signal activates the exhaust gas recovery system sequence control device 10 to start the subsequent sequence.

At this time, in order to ensure the safety of the recovery system, first, the CO generated from inside the furnace is completely combusted with the oxygen in the air taken in from the air suction hole 4, and the gas after combustion is converted into inert gas such as CO2 and N2. A mixture is formed, and control is performed to replace the inside of the recovery tact 3 with this inert gas. In this case, the amount of air from outside the system for complete combustion can be controlled by an air amount adjusting device such as the opening of the gate 5 or by using a damper 12 for controlling suction gas.
You may use any of the following.

Next, the replacement status in the recovery duct is confirmed by gas analysis, and when safety is ensured, the slide gate 5 is closed, and the tamper 12 is used to control the recovery of the gas generated in the furnace while the rice is being combusted. Implemented.

An example of the sequence from the above-mentioned blowing start to the start of unburned gas recovery is shown in FIGS. 4(A) and 4(B), and a blowing sequence including the above is shown in FIG. 5.

Effects of the Invention As described above, according to the method of the present invention, blowing is started with the exhaust gas hood and the converter mouth in close contact,
Since ignition can be confirmed, unnecessary operations such as raising and lowering the exhaust gas hood can be avoided, and since the furnace is sealed after the start of blowing, unburned gas can be efficiently recovered, which is extremely effective for heat recovery. It is. Furthermore, since it is possible to prevent gas from blowing out of the system, it is an excellent method in terms of pollution control and safety measures, and is extremely valuable in terms of converter operation.

[Brief explanation of the drawing]

Fig. 1 is an explanatory diagram showing the entire water droplet, Fig. 2 is a block diagram of the signal processing device, Fig. 3 is a diagram showing the signal processing state of the signal processing device, Fig. 4 (A), (B), A diagram showing an example of the sequence from the start of blowing to recovery of unburned gas,
FIG. 5 is a diagram showing an example of a blowing sequence. 1.---Converter, 2.. Exhaust scum hood, 3.. Exhaust scum collection duct, 4.. Air intake hole, 5. φ. Slide gate, 6.. ψ drive cylinder, 7.. Through hole, 81
...In-furnace optical detection probe, 82...Photoelectric conversion device,
9...Signal processing device. 10... Utilized gas recovery system sequence ilj control device, 1
1. Ichiban lance, 12...-damper, 13...-21'
+ & Transformation! J route, 14 dispute - peak hold circuit, 15
... Continuity r4J constant circuit. Representative Patent Attorney Ii' Ni Nil Figure 4 (A) Figure 4 (B)

Claims (1)

[Claims] In a closed converter operation method in which the converter mouth and the exhaust gas hood are brought into close contact, a light detection device is installed in a through hole provided in the side wall of the converter, and the in-furnace light detection signal from the detection device is detected. A method of operating a closed converter characterized by detecting ignition and proceeding with a blowing sequence.