JPH07228907A - Method for preventing leakage of water from broken tuyere - Google Patents

Abstract

PURPOSE:To temporarily repair the broken position without stopping furnace operation by detecting the broken position with a breakage detector arranged at a tuyere cooling water outlet side system and reducing supplied flow rate until water pressure balances with the pressure in a furnace. CONSTITUTION:Ordinarily, the inner part of the tuyere 5 has a double pipe structure having a cooling water pipe part 6 and closely fixed to an iron shell 1 of the blast furnace and a tuyere brick 2. When the breakage of tuyere develops, the cooling water is leaked from the cooling water pipe part 6. The difference between the supplying water rate and the draining water rate. i.e., the differential flow rate in the cooling water pipe part 6 is measured with a flow meter in the tuyere. The differential flow rate is proportional to the degree of the tuyere breakage. The supplying water flow rate is reduced until the water pressure of the cooling water balances with the pressure in the furnace. The water pressure at the time of becoming zero to the differential flow rate is the one which both pressures balance. Molten drips in the furnace are collided and brought into contact with the tuyere broken part and the broken part is deposit-welded to stop the leakage.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for repairing water leakage when a tuyere of a blast furnace is damaged by detecting a damaged portion and adjusting the supply water pressure without stopping the blast furnace.

[0002]

2. Description of the Related Art Blast furnace tuyere is the most important maintenance equipment having functions such as high pressure air blowing, fuel injection and oxygen potential control in order to control the reaction in the furnace. Usually, the tuyere is composed of outer layer metal fittings, large tuyere and blower tuyere, and is generally a double pipe made of pure copper. FIG. 5 shows the structure of the normal tuyere 5. Usually, the inside of the tuyere 5 has a double pipe structure having the cooling water pipe portion 6, and is tightly fixed to the blast furnace iron shell 1 and the tuyere brick 2 by the tuyere receiving material 3 and the large tuyere 4, respectively. Recently, the cooling water has been speeded up and a plurality of water cooling chambers have been mainly used, and the flow rate of the cooling water is generally used in the range of 300 to 500 l / min.

With the increase in the tapping amount of the blast furnace and the high-pressure operation of the tuyere, the usage conditions thereof are becoming severe. For this reason, the effect of tuyere troubles on blast furnace operation is greater than before, and in particular, the occurrence of cooling water leakage at the tuyere is a serious problem in the productivity of the blast furnace. If the tuyere breaks and cooling water begins to leak into the furnace, the temperature of the furnace body is lowered or the reaction in the furnace is hindered. When this tuyere breakage occurred, there was no first aid measure for preventing the leakage of cooling water and maintaining the cooling function. Therefore, the production had to be stopped while the blast furnace was stopped and the damaged tuyere was replaced.

Particularly in a large-sized blast furnace, the effect of the tuyere replacement idle wind on the cost and the work is large, which has been a bottleneck in full production. In order to postpone this rest wind, a method of stopping the inundation in the furnace and repairing the damaged part in an emergency was desired. As a related art related to this, Japanese Patent Application Laid-Open No. 52-32803 discloses a method for repairing a casting pipe. However, this method is a method of incorporating an auxiliary repair pipe inside the cooling device, and there are many restrictions on application to tuyere, which cannot be solved by this method.
That is, in the case of tuyere, a repairing method for stopping the damaged portion more directly is required.

[0005]

SUMMARY OF THE INVENTION In order to solve the above-mentioned conventional problems, the present invention can maintain the tuyere cooling capacity when reducing the amount of cooling water when the tuyere is damaged, and the differential flow rate due to the damage is 2 l / min. The purpose is to suppress the influence on the operation in the furnace and to increase the pressure in the furnace to be higher than the water pressure as follows. That is, within the limit that does not cause melting damage to the tuyere due to the decrease in cooling water, the water pressure is reduced and after equilibrating with the pressure inside the furnace, the damaged tuyere for repairing the damaged part by welding droplets in the furnace Provide a method for preventing water leakage.

[0006]

DISCLOSURE OF THE INVENTION The present invention is intended to solve the above-mentioned problems, and its gist is to detect a breakage provided in a tuyere cooling water outlet side system when a tuyere of a blast furnace is damaged and cooling water leaks. The damage is detected by the vessel, and based on the relationship between the water pressure in front of the tuyere and the discharge flow rate, the flow rate of the supplied water is reduced until the water pressure and the pressure in the furnace are balanced, and then the damage is caused by the molten droplets in the furnace. This is a method for preventing water leakage from a damaged tuyere, which is characterized by fusion-bonding points to stop leakage. In the method of the present invention, when the tuyere is damaged, the damaged portion is detected and the damaged location is confirmed. For this detection, for example, there is a method of detecting the vibration by causing the furnace gas to flow into the tuyere and violently disturbing the cooling water containing the furnace gas to generate vibration. In the present invention, the flow rate of the cooling water system to the tuyere is used to detect the differential flow rate with, for example, an electromagnetic flow meter, and the differential flow rate is proportional to the size of the damage. Adopted.

Next, the equilibrium point at which the differential flow rate becomes zero is found when the flow rate of the tuyere cooling water decreases to the point where the flow rate of the tuyere cooling water is kept in equilibrium with the internal pressure of the throttling furnace. This equilibrium point is related to the size of the breakage, and in the case of a small breakage with a differential flow rate of, for example, 5 l / min or less, the equilibrium point will be reached early when the reduction degree of the cooling water is small. Next, with respect to the damaged tuyere in such a state, molten droplets dripping from the melting zone in the furnace are brought into collision contact with the damaged tuyere, and are welded to the damaged tuyere in the same manner as welding. It joins together to prevent leakage. The present invention will be further described based on examples.

[0008]

EXAMPLE FIG. 4 shows a schematic view of a damaged tuyere. Figure 4 (a)
Indicates a state in which the cooling water is severely leaked and before the cooling water is detected. The present embodiment is a method of repairing the occurrence of such a broken state. Therefore, in the present invention, the following study was conducted in order to obtain the knowledge about the characteristics of the cooling water amount of the blast furnace. FIG. 1 is a diagram showing the results of examining the relationship between the water supply pressure in front of four specific tuyere and the discharge flow rate at the time of periodic repair of a blast furnace. In normal operation, the water pressure in front of the tuyere is 14 kg / cm ²
However, if this is gradually decreased, the discharge flow rate will decrease in proportion to this. And normal furnace pressure 4.1 ~
Balanced with 4.3 Kg / cm ² is 310 l / mi
was found to be n. The limit of the water restriction of this embodiment is 3
It was set to 10 l / min.

FIG. 2 shows a chart of the tuyere electromagnetic flowmeter of this embodiment. According to Fig. 2, when the tuyere is damaged, the drainage amount is 9
And an abnormal point appears on the chart of the differential flow rate 10. The degree of damage is estimated by reading this differential flow rate. FIG. 3 is based on the chart of FIG. 2 in which the amount of drainage is changed and the value of the differential flow rate at that time is read. That is, FIG. 3 is a diagram showing the relationship between the differential flow rate and the drainage amount when the tuyere water amount is reduced.
When the difference in flow rate is large immediately before the amount of tuyere water is reduced, that is, when the breakage is large, the amount of reduction of the difference in flow rate with respect to the amount of reduction is large. However, it can be seen that when the amount of drainage is reduced to the limit, a fixed point is reached in all cases. Figure 2
From 310 to 300 l / min, there is a point where the differential flow rate becomes zero, and this point is the equilibrium point of water pressure and furnace pressure. When the differential flow rate is 5 l / min or less, that is, when the damage is small, the differential flow rate becomes almost zero at 400 l / min. However, at 300 l / min, gas accumulation occurs in the gas collector due to wind pressure fluctuations, so 310 l / min was set as the lower limit.

FIG. 4B shows a state in which molten droplets dropped from the melting zone in this state are welded to the damaged portion. As shown in FIG. 4B, the damaged portion is completely in a state in which the hole is closed by the attached pig iron and the repair is completed. As a result of carrying out the present invention as described above and postponing the suspension in the actual blast furnace, it is possible to extend the life of the blast furnace by 4 to 6 days after the tuyere damage.
As described above, the present invention detects a damaged portion of a tuyere without stopping the blast furnace, reduces the flow rate of the cooling water, balances the cooling water pressure and the furnace pressure, and then automatically uses the molten droplets. It is possible to close the damaged part by welding to.

Although the present invention has been described on the premise of high-pressure operation in a large blast furnace, the present invention is not limited to this.
That is, it is also applicable to semi-high pressure (intermediate pressure) operation in a large blast furnace and high pressure or normal pressure operation in a small blast furnace. In that case, according to the present invention, usually 300 to 650 l /
The flow rate of min is reduced to about 300 to 400 l / min and the differential flow rate at this time is set to 2 l / min or less. For semi-high pressure (intermediate pressure) operation and small blast furnace application,
It is considered that the water throttling amount can be applied by reducing the water throttling rate at substantially the same throttling ratio as in the present invention and setting the differential flow rate at that time to approximately the same range as the value in the present invention. Further, the amount of welding is not particularly limited, but the amount is determined depending on the size of the damage, and it is sufficient that the same amount of welding as the amount of normal build-up welding can be secured.

[0012]

EFFECTS OF THE INVENTION According to the present invention, the blast furnace which has been suspended when the tuyere is damaged is repaired temporarily without stopping, the life is extended and the production obstacle is eliminated, and the cost is disadvantageous. And prevent the work load. In addition, the ingress of water into the furnace can be prevented and the factors that hinder the stabilization of operation can be eliminated.

[Brief description of drawings]

FIG. 1 is a diagram showing a relationship between a drainage flow rate and a front tuyere water supply pressure according to the present invention.

FIG. 2 is a diagram showing an electromagnetic flow meter chart showing the degree of tuyere damage of the present invention.

FIG. 3 is a diagram showing a relationship between a drainage amount and a differential flow rate according to the present invention.

FIG. 4 is a diagram showing a tuyere state of an embodiment of the present invention (a) before repair and (b) after repair.

FIG. 5 is a view showing a structure of a normal tuyere.

[Explanation of symbols]

 1 ... Blast furnace iron crust 2 ... Tuyere brick 3 ... Tuyere receiving material 4 ... Large tuyere 5 ... Regular tuyere 6 ... Cooling water pipe section 7 ... Tuyere damaged section 8 ... Repair section 9 ... Discharge amount chart 10 ... Differential flow chart

Claims (1)

[Claims] 1. When the tuyere of the blast furnace is damaged and the cooling water leaks, the damage is detected by a damage detector provided in the tuyere cooling water outlet system, and the pre-tuyere water supply pressure and the drainage flow rate are detected. Based on the relationship between the water pressure in the furnace and the pressure in the furnace, the flow rate of the supplied water is reduced until the water pressure in the furnace equilibrates, and then the broken droplets are fused and the leakage is stopped by the molten droplets in the furnace. Leakage prevention method.