JPS63176411A - Detection of slag foaming in converter - Google Patents

Abstract

PURPOSE:To predict slag foaming in an early period and to stabilize the condition of a converter by inserting a sub-lance mounted with a photodetector at the top end into the converter during converter operation and computing the fluctuation in the field area of an observation hole changing with the slag sticking near the observation hole of the photodetector. CONSTITUTION:The sub-lance 2 which has the furnace inside observation hole 3 at the top end and the photodetector 4 behind said hole is inserted into the converter and the photovideo on the inside of the converter is detected through the observation hole 3. The detection signal thereof is projected on a monitor 6 through a video processor 5. The fluctuation in the ratio at which the slag sticking and forming near the hole 3 occupies the field area of the hole 3 is computed by an arithmetic unit 7. The result of the computation is sent to a decision device 8 which compares the same with the predetermined initial field area of the hole 3 as a reference. An alarm for the generation of the slag foaming is emitted from an alarm device 9 at need according to the result thereof so that the slag foaming is prevented. The decrease in the yield of tapping by sloping and the decrease in the recovering rate of gaseous OG are thereby prevented and the oxygen blowing operation is stabilized.

Description

[Detailed Description of the Invention] [Industrial Application Field] This invention relates to a method for detecting slag forming by constantly monitoring the situation inside a converter furnace during blowing, and thereby predicting the occurrence of slopping. This is what I am trying to do.

[Conventional technology]

During blowing in a converter, molten slag is formed into slag depending on various conditions such as slag composition, viscosity, and oxygen content in the slag, and if this progresses excessively, sloping occurs. When slopping occurs, the steel melting components.

In addition to affecting the total tapping yield, etc., it also reduces work efficiency.
This causes problems such as a decrease in the OG gas recovery rate, deterioration of the working environment such as the generation of red smoke, and damage to equipment.

Therefore, the situation inside the converter furnace can be predicted quickly.

It is necessary to perform proper converter operation to prevent the occurrence of slopping, and various methods as shown below have been proposed so far. That is, (1) estimate the amount of slag in the furnace based on exhaust gas information during blowing;

■During blowing, the slag level is estimated from changes in the frequency and intensity of the sound generated from inside the furnace.

■Slag Levelne estimates the state of the slag by observing changes in vibration of the lance and furnace body during blowing, and changes in waveforms.

■Understand the radiant energy at the top and bottom of the furnace body as temperature, and predict the occurrence of slopping from temperature changes, peak values, etc.

■During blowing, microwaves are projected directly into the furnace from the top of the furnace to estimate the slag level using the principle of FM radar.

There are other methods.

[Problem that the invention seeks to solve]

However, with the method (2) of estimating the amount of slag in the furnace based on exhaust gas information during blowing, there is a time delay due to the analysis of exhaust gas, and the occurrence of slopping is not caused solely by the amount of slag. Since there is no such thing, there are problems such as low prediction accuracy. Frequency 1 of the sound generated from inside the furnace during blowing
The method of estimating the slag level from changes in strength requires determining the slag level and slag condition because it is an indirect measurement method.
There are problems such as the fact that it cannot be grasped in a single way, and that the prediction accuracy is low because the sound changes not only due to the slag forming situation but also when the furnace pressure changes due to changes in the amount of oxygen supplied. (2) A method for estimating the slag level or slag condition by understanding changes in the vibration of the lance and furnace body during blowing, and changes in waveforms;
The method (2), in which the radiant energy in the upper and lower parts of the furnace body is understood as temperature, and the occurrence of slopping is predicted from temperature changes, peak values, etc., has the same problem as the method (2). Y! During blowing, microwaves are projected directly into the furnace from the upper part of the furnace mouth to estimate the slag level using the principle of FM radar. The problem is that the tip of the sensor is severely damaged due to such factors.

As described above, there is currently no effective method for predicting the occurrence of slopping, and therefore there has been a desire to develop a new method for early and accurate detection of slug forming.

The present invention was made to solve the above problems, and by quantitatively understanding the slag forming situation during converter blowing, it is possible to detect and detect the occurrence of slopping during converter blowing in advance. The objective is to predict the situation and improve the total yield of steel, stabilize the blowing process, and improve the OG gas recovery rate.

[Means for solving problems]

The configuration of the present invention will be explained below.

First, an observation hole inside the furnace was installed at the tip of the sublance that can be raised and lowered to enter and exit the converter from above.

A light detection device is provided at the back of the furnace observation hole to detect an optical image of the inside of the furnace from the depth of the observation hole when the sublance is moved up and down to a proper position during converter blowing.

An image of the vicinity of the observation hole inside the reactor is analyzed from among the optical image signals obtained by the photodetector.

The ratio of the viewing area of the observation hole in the furnace that changes due to the slag that adheres to and forms near the observation hole and the fluctuations in that ratio are extracted.

Then, compare these with the initial field of view area of the observation hole inside the reactor, which is a predetermined standard.

This allows slug forming to be detected.In the present invention, one or more photodetecting devices are provided at the tip of the sublance that can be raised and lowered, so the detection position can be changed freely.

〔Example〕

Hereinafter, a specific embodiment of the method of the present invention will be described based on the drawings.

Figure 1 is an explanatory diagram showing the equipment configuration when the method of the present invention is implemented in a 250T/CH top-bottom blowing converter (1). In Figure 0, (1) is the main lance, and (2) is the converter. (1) shows a sub-lance that can be raised and lowered.

A photodetector (4) is incorporated in the tip of the sublance (2), and the photodetector (4) is shown in FIG. 2(a).
As shown in (b), it is attached to the inside of the furnace observation hole (3) provided in a circular shape at the tip of the sub-lance (2), and it is attached to the inside of the furnace from the back of the furnace observation hole (3). It is designed to detect optical images (this in-furnace observation hole (3) can be provided at various angles). In this embodiment, the purge gas sent out from the purge gas cover device (to) is further jetted out from the observation hole in the furnace (3), and the photodetector (4) is
) allows observation of the situation inside the furnace.

The optical image signal inside the furnace obtained by the photodetection device (4) is displayed on the monitor (6) via the image processing device (5), and is also transmitted to the image processing device (5) by the arithmetic device (7). The observation hole inside the reactor (
3) The proportion occupied by the visual field area of the in-furnace observation hole (3), which changes due to slag adhering to and generated in the vicinity, and the fluctuation in the proportion are calculated. Furthermore, the calculation result is sent to the next determination device (8), compared with the calculation result based on the initial visual field area of the in-reactor observation hole (3) determined in advance, and an alarm device (9) is sent as necessary. Slag forming inside the furnace is detected by issuing an alarm.

A circular furnace observation hole (3) is provided at the tip of the sub-lance (2) that can be raised and lowered, and when purge gas is ejected and the state of the molten steel Ql in the furnace is observed using the photodetector (4), the state of the molten steel Ql in the furnace is observed. As shown in Figure 3 (a), when the amount of slag (10) is relatively small in the early stage of blowing, the field of view reflected on the monitor (6) is the high temperature gas generated in the furnace, as shown in Figure 3 (b). It is covered with emitted white light α2.

As slag formation progresses and the amount of slag increases as shown in Figure 4 (a), adhering slag (lla) gradually forms near the observation hole (3) as shown in Figure 4 (a). but.

Due to the ejection of purge gas, it is not generated beyond a certain area of the observation hole (3).

If the amount of slag aυ increases further and slag I overflows out of the furnace due to so-called slopping as shown in Fig. 5(a), the monitor (6) as shown in Fig. 5(b) )
The field of view of the observation hole (3) reflected in the image is covered almost entirely by the adhered slag (11a).

In this embodiment, the alarm device (9) issues a warning before this happens, and slopping suppression action is taken. On the other hand, in order to clarify the difference between this embodiment and the prior art.

A method of predicting slopping using another method (conventional method) and taking action to suppress slopping was also implemented as a reference example.

The test results are shown in the table below.

Table note: When using the method of the present invention, when a warning is issued, slopping suppression action is always taken.

As shown in the table, the number of times that slopping did not occur as a result of taking slopping suppression actions when the alarm device (9) issued an alarm was 40 (the number of times that slopping did occur is In contrast, when predicting slopping using the conventional method,
While the number of times that slopping did not occur was one, the number of times that slopping occurred was extremely high, 50 times, which indicates that the prediction accuracy is low. In most cases where slopping occurs in conventional methods, slopping occurs when slopping is not predicted, and appropriate action to suppress slopping cannot be taken. Note that 1. Slopping did not occur when there was no alarm when using the method of the present invention. [Effects of the Invention] As detailed above, the method for detecting slag forming of the present invention is suitable for detecting slag forming during blowing. As it is possible to accurately assess the situation of slag forming, it is possible to quickly and accurately respond to situations where slopping may occur, which is extremely important in converter operation. It has value.

[Brief explanation of the drawing]

Fig. 1 is an explanatory diagram showing the configuration of the apparatus used when implementing the method of the present invention, Fig. 2 (a) (bl shows the configuration of the tip of the sub-lance, and Fig. Same figure υ】
is its bottom view, Figure 3 (a) is an imaginary diagram of the condition inside the converter showing the predicted conditions of the converter at the early stage of blowing, Figure 3 ('b) is an explanatory diagram showing the monitor image at that time, and Figure 4 (a) is an imaginary diagram of the condition inside the converter showing the predicted state of the converter when slag formation progresses due to blowing, Figure (b) is an explanatory diagram showing the monitor image at that time, and Figure 5 (
a) is an imaginary diagram of the condition inside the converter showing a prediction of the condition of the converter when slopping occurs during blowing; FIG. 4B is an explanatory diagram showing a monitor image at that time. In the figure, (1) is a top-bottom blowing converter, (2) is a sublance, and (3)
indicates the observation hole inside the furnace, (4) indicates the light detection device, (1G indicates molten steel, negative υ indicates slag, (1ia) indicates attached slag, and α2 indicates white light. Patent applicant Nippon Kokan Co., Ltd. Inventor Ori 1) Actual number
1 Figure *3m Procedural amendment (1) Koku C summons + [February 4, 162 Mr. Akio Kuroda, Commissioner of the Japan Patent Office]
Indication of two cases 1988 patent original page No. 6060
No. 2, Name of the invention: Method for detecting slag forming in a converter (412) Nippon Kokan Co., Ltd., Agent, Date of amendment order: Showa year, month, day supplement
Correct Contents 1 The table on page 9 of the specification of the application is corrected as follows.

Claims (1)

[Claims] Observation inside the furnace at the tip of the sublance that can be raised and lowered At the same time as making a hole, there is a A light detection device that detects optical images inside the furnace and the optical image obtained by the photodetector Attachment and generation from the signal near the observation hole The view of the observation hole inside the furnace changes depending on the slag We extract the proportion of the field area and the changes in that proportion. the first observation hole in the reactor as required in advance. Compare the period field area as a standard and create a slug graph. Converter characterized by detecting heating Slug forming detection method.