JPS61119609A - Method for operating blast furnace - Google Patents

Abstract

PURPOSE:To maintain the accumulation amt. of molten iron and slag at a specified level or below and to operate stably a blast furnace by measuring continuously the molten iron temp. during tapping from the blast furnace and discriminating the closing period of the tap hole in accordance with the measured value. CONSTITUTION:The tap hole 2 of the blast furnace 1 is opened to tap the high- temp. molten iron in the hearth to a large spout 4. The molten slag is separated in a spout 5. The molten iron is tapped by a molten iron spout 7 to a transport car, etc. The molten iron temp. is continuously measured by a fiber scope 9 during this time and the output signal thereof is recorded via a two-color pyrometer 9 and a converter 10 in a recorder 11. On the other hand, a time- differentiated value ( deg.C/min) is calculated by a calculator and the value thereof is recorded in the recorder 11. The change of the above-mentioned time differentiated value is continuously discriminated and the tap hole 2 is closed by a mud gun 3 when the value thereof exceeds certain negative reference value. The accuracy in the discrimination of the time for closing the tap hole is improved and the operation of the blast furnace is stabilized by the above- mentioned method.

Description

DETAILED DESCRIPTION OF THE INVENTION [Industrial Field of Application] The present invention relates to a method of operating an ironmaking blast furnace, and more particularly, to an operating method for determining the timing of tapping blockage.

[Conventional technology]

During tltl pig iron work in a blast furnace, a tap hole is opened 10 to 12 times a day using a mud gun, etc., and the tap iron is tapped into a large sluice. After separation from the slag, the hot metal is transferred from the slag to a hot metal car for transportation.

Additionally, as furnaces have become larger in size, the number of tapholes installed has also increased.

When tapping hot metal from these blast furnaces, the timing of blockage of the lj:I pig hole is determined by (1) conventionally, workers at the front of the furnace check the tapping conditions, such as gas blowing from the tap hole and the flow rate of hot metal and slag. The timing of clogging has been determined either by observing and empirically determining (2) or by (2) changes in medium temperature in a heat medium distribution pipe immersed in a slag flow.

[Problem that the invention seeks to solve]

In the case of method (1) of the above-mentioned conventional techniques.

Due to individual differences among workers, there may be differences in determining the timing of closure,
In addition, since it is a place where there is a lot of hot metal scattering, it is difficult to carry out continuous checks, making it necessary to rely on VC for spot checks.

In addition, in the case of method (2), the pipes immersed in the slag are subject to severe wear and tear, and especially if hot metal is mixed in the slag, there is a risk of major accidents due to pipe melting and leakage of the heating medium, which is dangerous. be.

Regardless of which method is used, if the VC dies, if the blockage is too early, the amount of residual pig iron and slag in the furnace will increase, causing a sudden change in the gas flow in the furnace and cooling the furnace.If it is too late, the gas in the furnace will blow out, causing environmental problems. In addition, a large amount of molten metal slag is scattered, making it impossible to close the mud gun and causing a wind outage.

As mentioned above, for stable operation of a blast furnace, it is important to maintain the amount of accumulated hot metal and slag in the furnace below a certain level, and for this reason, there is a need for an improvement in the method for determining when the tap iron is blocked. It had been.

[Means for solving problems]

The present invention has been made to improve the above-mentioned prior art and maintain the accumulated amount of hot metal and slag within a certain level in the furnace. This is a blast furnace operating method that determines the time of blockage by measuring.

In addition, the blast furnace operation method determines when the tap iron is closed when the time differential value of the continuous value of the measured hot metal temperature exceeds a negative set value using a computer.

FIG. 1 is a schematic diagram for explaining the method of the present invention.

In Figure 1, % 1: blast furnace, 2: gun port, 3: mud gun, 4: large gutter, 5 Nislag gutter, 6: small tank, 7: hot metal gutter, 8: fiber scope, 9: 2 color thermometer, 10
: Converter, 11: Recorder, 12: Calculator Ruru.

First, the tap hole 2 of the blast furnace 1 is opened with a mud gun, and 1 cItl of hot metal in the pool is poured into the large trough 41' (
The molten slag is separated by gravity sedimentation and separated in the molten slag trough 5, and the hot metal is tapped from the molten pig iron trough 7 via a small tampolo to a transport vehicle (not shown) and transported as appropriate. During this time, the temperature of the hot metal was continuously measured using the fiberscope 9 vC inserted into one end of the small tank.
The output signal is recorded in the recorder 11 via the two-color thermometer 9 and the converter 1o, and a time differential value (V minute) is calculated by a single computer, and that value is also recorded in the recorder 11.

Changes in the above-mentioned time differential value are continuously determined, and when this value exceeds a negative reference value, the tap hole 2 is closed by the mud gun 3.

[For production]

In the case of the method of the present invention, the tapping temperature is such that at the initial stage of tapping (A-B), that is, from 0 to 40 minutes, as shown in FIG. Although the measured hot metal temperature itself is low, there is a strong possibility that it will increase. During the middle period (B-C) 40 to 90 minutes, the hot metal temperature measured by the high temperature hot metal in the pool gradually rises to C, av
The maximum temperature is reached at c, but the differential value decreases by the IVT order, and after 90 minutes at the end of tapping (C-D), the hot metal temperature also decreases and the time differential value shows a negative value. That is, in the method of the present invention, the time differential value (°C/min) is determined by a computer from the continuous measurement values of the hot metal temperature, and the tapping temperature is determined based on the trend of this time differential value. It should be possible to accurately determine the timing of tap blockage without being affected.

Examples of embodiments of the present invention will be described below.

〔Example〕

With a continuous hot metal temperature measurement system as shown in Figure 1,
Changes in hot metal temperature from the start of tapping to the end of tapping were measured. The results are shown in FIG.

In FIG. 2, arrow A shows the point at which tapping starts, B shows the point at which the temperature rise of the large trough is completed, C shows the point at which the hot metal reaches its maximum temperature, and D shows the point at which the hot metal and slag drawing are completed.

As shown in Figure 2 (I), 0 to 4 at the initial stage of tapping (A to B)
At about 0 minutes, the measured hot metal temperature rises rapidly because the hot metal is being cooled until the temperature of the large gutter rises. Then B
After this point, cooling by the large gutter is completed and the temperature of the hot metal gradually rises.

During 40 to 90 minutes of the middle stage of tapping (B-C), high-temperature hot metal on the surface layer of the sump in the furnace is extracted, and at about 90 minutes C point, the tapping temperature reaches a maximum temperature of about 1530°C.

After 90 minutes at the end of tapping (C-D), the hot metal temperature decreases because the hot metal whose temperature has been lowered due to furnace bottom cooling, which has a long residence time at the furnace bottom, is extracted.

The time differential value of these continuously measured hot metal temperatures is calculated by the computer 12. The results are shown in Figure 2 (1).

The time differential value shown in FIG. 2 (II) is a negative reference value.

In this example, the tap hole was blocked using a mud gun when the temperature exceeded 1.5°C/min.

As a result of the above method, unlike when using the conventional method, there was no sudden change in the gas flow in the furnace, no ctX emission from the gas in the furnace, etc.
The level of the amount of hot metal and slag accumulated in the furnace was kept constant, and the furnace conditions and furnace heat were stabilized.

〔Effect of the invention〕

According to the method of the present invention, in blast furnace operation, 'f' during tapping
The σ pig iron temperature is continuously measured, the time differential value is calculated from this measured value, and the time when the calculated differential value exceeds a negative reference value is determined to be the time of tap iron blockage, which is different from the conventional method. Unlike the method that relies on temperature change due to a heat medium,
Judgment accuracy is improved.

This will contribute to stabilizing blast furnace operations.

[Brief explanation of drawings]

FIG. 1 is a schematic diagram for explaining the method of the present invention. FIG. 2 shows a diagram of the embodiment of the present invention during tapping, showing 1... blast furnace, 2... ltj pig iron mouth, 4... large gutter, 5... slag gutter, 7... hot metal Gutter, 8... fiber scope, 11... log meter, 12... calculator.

Claims (1)

[Claims] A method for operating a blast furnace, characterized in that the timing of tap plug blockage is determined by continuously measuring the temperature of hot metal during tapping in a blast furnace.