JPS59104408A - Detection of bonded zone by fusion of blast furnace - Google Patents

Abstract

PURPOSE:To highly accurately measure the shape, position, etc. of bonded zone by fusion, by a method wherein the fusion-bonded zone formed in blast furnace is measured by inserting a rod-shaped object to penetrate through the inside of furnace from the furnace wall and by measuring the insertion resistance. CONSTITUTION:A rod-shaped object 13 is inserted into the blast furnace 1 from the nozzle part 8 of the penetrating hole provided through the furnace wall 19 of blast furnace 1 and one end thereof is connected to a traveling truck 11 running on the rail 10 arranged on a stand 18 with a driving chain. The rod shaped object 13 goes forward and backward synchronously with the traveling of truck 11 according to the advance and retreat of driving chain 12 driven with a driving device 20. A pulse transmitter 21 is continuously connected to the motor shaft 20a of this driving device 20 and the change of inserting speed of rod shaped object 13 and the distance from the furnace center at the position where change is generated are calculated with an arithmetic unit 22 by detecting the angular velocity of motor shaft 20a. The shape and position of fusion bonded zone is detected by recording said motion with a recorder 23.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a cohesive zone detection method that contributes to stabilizing control of blast furnace operation.

Iron ore raw materials and coke are alternately charged into the blast furnace, and they gradually descend while being reduced by the reducing gas that rises from the bottom. Ore that has undergone a compositional change due to reduction exhibits a softening and melting temperature unique to each ore, but since the temperature inside the blast furnace is higher in the lower part, the ore on its way down will eventually reach the same level as the softening and melting temperature. temperature range.

In this case, ordinary ore does not melt all at once from a lumpy zone, but undergoes a process of softening, melting, and then dripping over a certain temperature range, and hot metal and slag are formed in (2). That is, a softened and fused ore layer exists in a certain part of the furnace, and the area where these layers exist is called a softened and fused zone (hereinafter simply referred to as a fused zone). The shape of such a cohesive zone inside a blast furnace was previously only a matter of speculation, but it has come to be understood fairly accurately through blast furnace dismantling surveys conducted by blast furnace companies recently, and since then it has been understood quite accurately in blast furnaces. The shape of the cohesive zone during operation is also being detected by various means. According to this study, it was found that the shape of the cohesive zone inside the furnace exhibits a significantly large distribution in the height direction and horizontal cross-sectional direction inside the furnace, and that these distributions are closely related to the conditions inside the furnace. There is. Although it is known that various patterns are shown depending on the conditions of the blast furnace, the most standard pattern is shown schematically in FIG. That is, in Fig. 1, 1 is a blast furnace, and the furnace top 1a
Ore 3 (regardless of the distinction between pellets, sintered ore, etc.) and coke 4 are charged alternately in layers and then descend one after another while remaining solid. Note that 6 is such a massive band.

Further, from the shaft portion 1b downward, a cohesive zone 7 is formed in a layered and mountain-like manner, and a core coke layer 5 contained therein is formed.
Hot metal and slag drip through the gaps. On the other hand, hot air is blown from the tuyere 2 and rises as shown by the arrow, but the porosity of the cohesive zone 7 is extremely small due to its physical nature, so ventilation is extremely poor and the inside of the furnace is In this case, it becomes a resistance plate for the rising gas. Therefore, the core coke layer 5
As shown by the arrow in Figure 1, the reducing gas that has passed through and ascended is distributed in the height direction and horizontal direction when it reaches the cohesive zone 7, and the upward gas is distributed in the layer of the cohesive zone 7. The gas rising in the core coke layer 5 along the horizontal direction passes through the coke slit 7' sandwiched between the cohesive zones 7 and exits to the lump zone 6 side. That is, the cohesive zone 7 exhibits a distribution function for rising gas, and the degree of dispersion of the gas in the furnace is greatly influenced by its formation state, particularly its distribution. For example, when the cohesive zone 7 is present in the furnace abdomen extending toward the core side, the gas flow at the top of the furnace is mainly a peripheral flow, and when the cohesive zone 7 is present biased toward the furnace wall side, the gas flow mainly forms a central flow. When a peripheral flow is formed, the reduction in the lumpy zone 6 is accelerated at the periphery, while when a central flow is formed, the opposite is true, but these directly influence the formation of the next cohesive zone. Not only that, but it is also the main controlling factor for the reduction process in the entire furnace.

From the above, it is clear that the shape of the cohesive zone has a significant effect on smooth unloading and effective gas distribution in the blast furnace, and in order to maintain smooth operation of the blast furnace and achieve high productivity. found that it is necessary to properly maintain the shape of the cohesive zone in the furnace. However, in order to do so, it is first necessary to understand the current shape of the cohesive zone as accurately as possible during reactor operation. Regarding these, JP-A-49-7
2115, 51-25415, Utsukai 51-3010
4, 51-28304, and JP-A-56-9840
7 and other proposals have been made, and attempts are being made to understand the situation through estimation calculations or dynamic analysis in actual reactors, but none of these methods can be said to be particularly established.

The present invention has been made in view of these circumstances, and is intended to establish a method that can measure the position and shape of the cohesive zone in an actual furnace as quickly and accurately as possible. To explain its structure, the gist is to measure the cohesive zone formed inside the blast furnace by inserting a rod-shaped object from the furnace wall into the furnace and measuring the insertion resistance during blast furnace operation. It is something.

The structure and effects of the present invention will be specifically explained below.
The embodiment described below is only one specific example, and various changes in design in accordance with the spirit described above and below are within the technical scope of the present invention.

FIG. 2 is an explanatory diagram illustrating the cohesive zone detection method of the present invention. The figure shows a nozzle part 8 of a through hole provided in the furnace wall 19 of the blast furnace 1.
The rod-shaped body 18 is shown inserted into the blast furnace 1 from above. One end of the rod-shaped body 13 is connected to a traveling truck 11 that moves on a rail 10 provided on a pedestal 18 by a drive chain 12, and as the traveling truck 11 moves back and forth, the rod-shaped body 13 moves into the core of the blast furnace 1. Move forward or backward in the direction. The drive chain 12 is driven by a drive device 20 (generally using an air motor, hydraulic pressure, electric motor, etc.) and a drive transmission device 24 that transmits the drive. The drive chain 12 pulls the traveling carriage 11 in the direction of the arrow by the drive transmission device 24 and the plurality of sprocket wheels 9, so that the rod-shaped body 13 connected to the traveling carriage 11 moves toward the inside of the blast furnace 1. . Shutoff valves 14 and 1 in the same figure
5. The sealing device 16 and the like are devices that are operated before and after inserting the rod-shaped body 13 into the blast furnace and during measurement, and their functions will be briefly explained below. When inserting the rod-shaped body 13 into the blast furnace 1, the shutoff valve 15 is opened and the drive device 20 is activated to drive the drive chain 12.
The carriage 11 is pulled by the drive chain 12 and runs on the running rail 10. The rod-like body 13 connected to the traveling truck 11 starts to be driven together with the traveling truck 11, and is inserted into the guide pipe 17 through the opened shut-off valve 15 and reaches the closed shut-off valve 14. At this point, the shutoff valve 14 is opened. Even if the furnace is opened, the sealing device 16 prevents the gas inside the furnace from flowing to the outside. In this way, the rod-shaped body 13 can be smoothly advanced into the blast furnace while preventing leakage of furnace gas and the like.

By the way, the insertion resistance of the rod-shaped body 13 into the furnace is estimated to vary considerably depending on the insertion position, as is clear from FIG. 1 and the explanation thereof. That is, since the charge is gradually descending as described above, even if the bar insertion position is determined, it may hit the lumpy zone 6 of ore and coke or the cohesive zone 7 depending on the time. The insertion resistance applied to the rod 18 varies significantly depending on the position at which the rod 18 enters, and the insertion speed of the rod 18 changes accordingly. Therefore, in the present invention, the motor shaft 2 of the drive device 20
A pulse transmitter 21 is connected to 0a to detect the angular velocity (or rotational speed) of the motor shaft 20a, and the arithmetic unit 22 calculates changes in the insertion speed of the rod-shaped body 18 and the distance from the core to the point where the change occurs. (The approach distance of the rod-like body 13 until the angular velocity (or rotational speed) decreases is determined) is calculated and recorded in a recorder 23 connected to the calculation device 22. The detected rotational speed is integrated in the arithmetic unit 22, and the rotation speed is integrated until the resistance increases, and when the resistance increases (when the tip of the rod-shaped body 13 enters the core, the resistance decreases again). The insertion depth of the husband is calculated, and the position (distance from the furnace wall) and width of the softened cohesive zone viewed in the furnace width direction are recorded on the recorder 28.

In the above embodiment, a rod-shaped body was used as the device inserted into the furnace, but instead of this, a sonde, a lance, etc. for temperature, pressure, and gas analysis, which are recently used in large blast furnaces, may be used.
Any rod-like material that can be inserted into a high-temperature blast furnace may be used.

FIG. 3 is an explanatory diagram of the measurement results in the example, and is a diagram showing the relationship between the insertion speed of the rod-shaped body obtained using a calculation device and the depth from the reactor wall in the direction of the reactor core. In Figure 3, (a) shows the measurement results at the uppermost position of the blast furnace cohesive zone, and (b)
The figure shows the measurement results at the lower position, where the vertical axis is the value obtained by converting the angular velocity (or rotational speed) of the drive shaft 20a into the insertion speed of the rod-shaped body 13, and the horizontal axis is the value obtained by converting the angular velocity (or rotation speed) of the drive shaft 20a into the insertion speed of the rod-shaped body 13. Show distance. Looking at Figure (a) in relation to Figure 1, we see that blast furnace 1
While the inserted rod passes through the lumpy zone 6 where ore 3 and coke 4 are piled up, the insertion resistance is not so great and the rod advances toward the core at the same speed, but the cohesive zone (top) When it reaches 7, it enters a semi-molten ore layer with high viscosity and the insertion resistance increases rapidly, so the insertion speed decreases rapidly. It is understood that after passing through the cohesive zone 7, the insertion speed once again enters the lumpy zone 6 and the insertion resistance decreases to the same level as before, so that the insertion speed remains the same as before.

Next, in the position measurement results shown in the lower part of the figure (b), the burning coke layer 5 and cohesive zone 7 have spread to the vicinity of the furnace wall, and the lumpy zone 6 has already reached the high temperature near the furnace wall where the rod was inserted. Therefore, the viscosity has increased, so the insertion resistance is greater than the upper stage, and the insertion speed is somewhat lower. Furthermore, as the resistance increases as the cohesive zone approaches, the insertion speed gradually decreases, and as the insertion resistance rapidly increases when the cohesive zone is reached, the insertion speed decreases significantly and the insertion speed advances toward the core. Next, after passing through the cohesive zone 7 and reaching the core coke layer 5, the insertion resistance gradually decreases, and the insertion progresses with almost no resistance near the core, so the insertion speed in Figure (b) is the same as that of the coke layer 5. It can be seen that the speed begins to rise rapidly after passing the belt, reaches the point of no resistance, reaches the maximum speed, and remains in an equilibrium state.

By performing the above measurements at several locations in the height direction and circumferential direction of the blast furnace, the shape and position of the cohesive zone can be accurately determined.

Since the configuration of the present invention is as described above, the shape, position, etc. of the cohesive zone in the furnace can be measured with high precision. Therefore, it has become possible to induce and maintain better blast furnace operation.

[Brief explanation of the drawing]

FIG. 1 is a schematic diagram showing a cohesive zone in a blast furnace, FIG. 2 is an explanatory diagram illustrating the cohesive zone detection method of the present invention, and FIG. 3 is an explanatory diagram of measurement results in an example. 1... Blast furnace 2... Tuyere 3... Ore 4... Coke 5... Core coke layer 6... Lump zone 7... Cohesive zone 8... Nozzle part 9...・Sprocket wheel 10...travel rail 11...travel trolley 12...
・Drive chain 13... Rod-shaped body 14... Shutoff valve
15...Shutoff valve 16...High pressure air piping 17
... Guide pipe 18 ... Frame 19 ...
・Furnace wall 20...Drive device 21...Pulse transmitter 22...Arithmetic device 28...Recorder 24...
・Drive transmission device

Claims (1)

[Claims] A method for detecting a cohesive zone in a blast furnace, characterized by measuring a cohesive zone formed in a blast furnace by penetrating and inserting a rod-shaped object into the furnace from a furnace wall and measuring insertion resistance during blast furnace operation.