JPS5832207B2 - Charge deposition layer thickness detection sonde - Google Patents

Description

Detailed Description of the Invention The present invention relates to a furnace in which coke, sintered ore, pellets, and lump ores (hereinafter referred to as ores) are charged in layers from the top of the furnace, such as a blast furnace or shaft furnace. The present invention relates to the structure of a detection sonde for measuring the thickness of a charge deposit by utilizing the difference in electrical resistance between coke and ore-like layers.

In reduction melting furnaces such as blast furnaces and shaft furnaces, coke and ores are charged discontinuously and alternately in predetermined amounts using a bell-shaped or rotating chute-type furnace top charging device.

In this case, in the bell-shaped charging device 1, the shape of the charge distribution changes depending on the position of the movable armor 2 in FIG. 1, and in the rotating chute-type charging device, depending on the inclination angle of the chute.

At the same time, the charge deposition layer thickness in the furnace radial direction also changes significantly.

As a result, the flow of gas in the furnace caused by air being blown from the slats in the lower part of the furnace is greatly affected.

In other words, there is less gas flow in areas where the ore layer with high ventilation resistance is thick, and conversely, gas flow is greater in areas where the ore layer is thin.

If this gas flow is significantly unbalanced, problems such as shelving, slipping, and gas blow-through may occur, making it impossible to maintain normal operation of the furnace.

Therefore, in order to maintain stable operating conditions, it is necessary to constantly adjust the layer thickness of the charge to obtain the desired gas flow distribution.

The layer thickness can be adjusted by changing the position of the armor plate 2 in a bell-type charging device, or by changing the angle of inclination of the chute in a rotating chute-type charging device. In order to adjust the thickness, it is necessary to reliably measure the thickness of the deposited layer.

1 and 2a and 2b show an example of a conventional charge layer thickness measurement method and an example of the structure of a detection sonde.

Here, Fig. 2a shows a detection sonde which is used when the charge particle size is relatively large in size of 30 mm or less, and Fig. 2 shows a detection sonde which is often used in cases where there are many coarse particles with a particle size of 30 mm or more. This is an example.

In this method, when the distance between a pair of electrodes is 40 mm, the electrical resistance of the coke deposited layer is 1 to 3 g, and the ore is 1000 to 1000.
0. This takes advantage of the fact that there is a large difference in Q between the two.

The electrical resistance measurement of the charge deposited layer is carried out using a sonde having a pair of electrodes 10.11 with the insulating material 12 in between. Determine whether it is a coke layer 5 or an ore layer 6 from the electrical resistance value of the charge that is inserted and fixed into the furnace and comes into contact with the electrode, determine the falling time t of the charge layer, and at the same time, The interface between the coke and ore layers is detected, and from the time it takes for this interface to descend between the two sondes 7.7', the rate of descent of the charge is
This method calculates the charge layer thickness from this V and t detected by the sonde 7 or 7'.

Therefore, how to accurately measure the electrical resistance of the charge is an important point in layer thickness measurement.

In addition, in FIG. 1, 3 indicates a measuring needle, and 4 indicates a furnace wall.

However, the measurement using the conventional detection sonde shown in Figure 2 a and b has the disadvantage that the measured electrical resistance of the contents in the furnace changes greatly over time, and after a certain period of time it becomes almost impossible to measure the resistance. .

Examples of this are shown in Figures 3a, b, and c. That is, two days after the installation of the detection sonde, the coke layer 1 to "Qz ore layer 80"
0~1000. However, after 20 days, the ore layer is 80~110. Q and after 50 days, 1
It becomes around 0Q, and it becomes impossible to determine whether it is a coke layer or an ore layer, and it becomes impossible to determine the charge layer thickness.

This is due to the detection sonde's electrode 10 inserted into the furnace.
The insulating material 12 between 11 and 2CO contains coke powder mixed with the furnace gas and CO gas contained in the furnace gas.
This is because C is precipitated by the reaction -+CO2+C, and this C adheres, causing insulation failure and reducing the electrical resistance between the electrodes 10 and 11 to the same level as the electrical resistance of coke.

The present invention solves these problems and makes it possible to measure the electrical resistance of a charge stably over a long period of time.

4a + b and FIG. 5 below show structural examples of the layer thickness sensing sonde of the present invention.

In FIG. 4a, a gas introduction pipe 14 is provided in the insulating material 12 between a pair of electrodes io and ii, leading to the tip, and a large number of circular or A donut-shaped disk-shaped adapter 15 with a rectangular or slit-shaped small hole is made of an insulating material and fitted.Meanwhile, a gas blowing pipe 13 is attached to the gas introduction pipe 14 from outside the furnace, and N2 is injected from the outside. It is characterized by having a structure in which a gas such as air is blown into the adapter 15 and the gas is ejected from a small hole in the adapter 15.

In addition, FIG. 4 shows a ring-shaped adapter 16 with many small holes fitted between the electrodes 10 and 11, and the gas introduction pipe 1
4. It has a structure in which gas is blown in from the gas blowing pipe 13 and gas is ejected from the small hole in the adapter 16.

Note that it is preferable that the holes provided in the adapter 15 or 16 be 2TnTILφ or less and ten or more holes so that the gas can be ejected as evenly as possible.

According to the detection sonde of the present invention, coke powder mixed with the furnace gas and C precipitated by decomposition of CO gas are blown away inside the furnace by the gas ejected from the insulating adapter 15 or 16, and the insulating material Since it does not adhere to the entire surface of electrodes 12, insulation between electrodes 10 and 11 is maintained, and the electrical resistance of the charge deposited layer itself can be measured stably over a long period of time.

Figure 6 shows that 60 years have passed since the detection sonde according to the present invention was installed.
An example of a measurement chart after a few days is shown, and it can be seen that the electrical resistance value is almost the same as the electrical resistance value immediately after installation in Figure 3a.

[Brief explanation of drawings]

FIG. 1 is an explanatory diagram showing a method for measuring the deposited layer thickness of charges;
Figures 2a and 2b are cross-sectional views showing an example of the structure of a conventional layer thickness sensing sonde, Figure 3 is an explanatory diagram showing changes over time in electrical resistance measurements when using a conventional sensing sonde, and Figure 4 Diagram a, b
5 is an enlarged explanatory view of a porous adapter, and FIG. 6 is an example of a chart when the detection sonde according to the present invention is used. 1... Bell, 2... Movable armor 13... Measuring needle, 4... Furnace wall, 5...
...Coke layer, 6...Ore layer, 7 and 7'...Detection sonde, 10 and 11...
... Electrode, 12 ... Insulating material, 13 ...
...Gas blowing pipe, 14... Gas introduction pipe, 15 and 16... Porous adapter.

Claims (1)

[Claims] 1. In a sonde that is charged into the furnace from the furnace wall of a reduction melting furnace such as a blast furnace or shaft furnace and measures the change in electrical resistance of the deposited layer of contents in the furnace to detect the thickness of the deposited layer, a pair of A donut-shaped disk-shaped or ring-shaped adapter having a large number of small holes is installed in the inter-electrode insulation part, a gas introduction pipe is buried in the insulation part, and the tip of the gas introduction pipe is communicated with the adapter and the rear A sonde for detecting charge deposit layer thickness, characterized in that its end is connected to a gas blowing pipe installed outside the furnace wall.