JPH0794682B2 - Blast furnace operation method - Google Patents

Description

The present invention relates to a normal raceway for improving the air permeability and liquid permeability in front of the blowing tuyere when restarting the operation when the blast furnace is blown for a long time or when the furnace is cooled. And the blast furnace operation method for ensuring the early recovery of the furnace condition.

Conventional technology During blast furnace operation, when the equipment is repaired or trouble occurs during operation, resulting in long periods of idle air or excessive furnace cooling, the molten material in the furnace or the semi-molten material is cooled in front of the tuyere at the start-up. A part of it solidifies to form a slag wall, or it is bubbling in a molten state (generally called slag spring).

Fig. 4 exemplifies this situation. In front of the tuyere (1) of the blast furnace, the slag wall (3) or slag spring made of semi-molten material such as slag and pig is formed on the surface of the core coke (2). (4) exists,
There is a problem that breathability and liquid permeability are significantly impaired and a normal raceway cannot be secured.

That is, when the blast furnace operation is restarted in the furnace-cooled state, the tuyere-
Due to deterioration of gas and liquid permeability between the tapholes, it is difficult to discharge the melt generated above the tuyere from the taphole to the outside of the furnace.

Especially in front of the tuyere, due to the slag wall (3) or slag spring (4) made of semi-molten material such as slag and hot metal, the permeability of this part and the liquid permeability of the generated melt toward the lower part of the furnace Deteriorates, induces retention of the melt in front of the tuyere, melting damage of the tuyere, etc., and further promotes cooling of the furnace by treatment with blast air, which causes secondary deterioration of operation.

Conventionally, as a countermeasure when a slag wall or a slag spring has formed in front of the tuyere, a method of applying an operational load stepwise over a long period of time with a low melt flow rate at which the molten material is simply dropped to the lower part of the furnace The method of restricting the tuyere to be blown, gradually melting it and discharging it out of the furnace, taking a rest, scraping the contents in front of the tuyere, or blowing it after melting by blowing oxygen etc. There is.

However, there is a drawback that it takes a long time to recover because the amount of air blown into the furnace is limited, and that the furnace cools further due to dead air.

SUMMARY OF THE INVENTION In view of the situation as described above, the present invention, when restarting the operation when the blast furnace is in a long period of quiescent air or when the furnace is cold, removes a slag wall or a slag spring in front of the blast tuyere during the operation. It aims to propose an operation method that aims at early recovery of the furnace condition by removing it in a relatively short time to secure a normal raceway.

Means for Solving the Problems This invention removes a slag wall or a slag spring in front of a blast tuyere,
As a means to secure a normal raceway, a mechanical force that breaks and removes by piercing the slag wall or slag spring in front of the tuyere with a gold rod inserted into the furnace through the tuyere during operation, or by giving an impact. Or a method using a dissolving means such as inserting a pipe in place of a gold rod and blowing oxygen to dissolve and remove the slag wall or the slag spring.

Action A gold rod that destroys and removes the slag wall or the slag spring in front of the tuyere, or a pipe that dissolves and removes the slag can be inserted, for example, from the part of the head cover behind the blow nozzle. In that case, it is necessary to provide a sealing means so that hot air does not blow out from the part of the head cover.

Gold rods and pipes are inserted into and pulled out of the furnace by a human-powered or hydraulic or pneumatic driving device.Also, a hydraulic or pneumatic driving device is used for the method of breaking slag walls and slag springs. Can be used.

A gold rod or an oxygen pipe is inserted into the furnace through a blast nozzle when necessary to break or melt the slag wall or slag.

The slag wall or slag spring in front of the tuyere is pushed down by a gold rod to improve liquid permeability and secure a raceway. Further, in the case of an oxygen pipe, the raceway is secured by melting the slag wall or the slag spring.

Embodiment FIG. 1 is a schematic vertical sectional side view showing an embodiment of the present invention, FIG. 2 is an enlarged view showing a state where a normal raceway is secured in front of the tuyere, and (9) is a blowing nozzle, (5) is a head cover, (6) is a gold rod, (7) is a raceway,
(8) is a gold rod drive device.

That is, when removing the slag wall (3) or slag spring (4) existing in front of the tuyere (1), the blast head (5) is opened from the opening of the head cover (5) behind the blast nozzle (9) while continuing the blast. Push down the slag wall (3) or slag spring (4) with a gold rod (6). This improves the liquid permeability in front of the tuyere, and gradually restores and secures the normal raceway (7).

Similarly, when an oxygen pipe is used instead of a gold rod, the slag wall (3) or the slag spring (4) in front of the tuyere is melted to improve liquid permeability, and a normal raceway (7) is secured. To be done.

FIG. 3 shows the actual start-up results of the blast furnace operation when the method of the present invention was applied to the blast furnace A (internal volume: 2700 m ³ ).

Fig. 3 shows that the tuyere of No.25 and No.28 is normal because the cooling water drainage temperature is almost constant, while the tuyere of No.26 and No.27 is The temperature of the tuyere cooling water drainage is gradually rising from the middle. This indicates that excessive furnace cooling solidified the in-furnace melt in front of the tuyere, causing cavitation and swelling during operation and increasing the heat load on the tuyere.

Therefore, regarding the tuyere of No. 27, a gold rod (20 mmφ, length 6
m) was struck and shocked for 6 minutes to destroy the spring. As a result, the liquid permeability was improved and the temperature of the tuyere cooling water drainage was gradually lowered. Also, the coke inside the raceway began to turn normally, and the normal raceway was restored in about 20 minutes from the end of driving the gold rod.

The tuyere of No. 26 was similarly impacted with a gold rod. However, in the case of No.26 tuyere, the increase range of the cooling water drainage temperature was smaller than that of No.27 tuyere, so the impact application time with the gold rod was set to about 30 seconds. As a result, the normal raceway was restored within 10 minutes after the completion of the driving with the gold rod.

Thus, the method of the present invention improved the liquid permeability in front of the tuyere in a short time, and shortened the recovery period by furnace cooling to about half that of the conventional method.

As described above, since the present invention is a method of destroying or melting and removing the slag wall or the slag spring without stopping the air flow when the slag wall or the slag spring in front of the tuyere occurs, the invention can be performed smoothly. Moreover, a normal start-up is possible, which has a great effect on the early recovery and stabilization of the blast furnace operation.

[Brief description of drawings]

FIG. 1 is a schematic longitudinal side view showing an embodiment of the present invention, FIG. 2 is an enlarged side view showing a state where a normal raceway is secured in front of the tuyere, and FIG. 3 shows the method of the present invention in an actual blast furnace. FIG. 4 is a vertical cross-sectional side view showing an example of the situation in front of the tuyere in a furnace cooled state when applied to the above. 1 ...... Tuyere 2 ...... Furnace core coke 3 ...... Slag wall 4 ...... Slag spring 5 ...... Head cover, 6 ...... Gold rod 7 ...... Raceway, 8 ...... Blower nozzle

Claims (1)

[Claims] 1. When restarting the operation when the blast furnace is blown for a long time or when the furnace is cold, measures are taken to mechanically dissolve or dissolve the slag wall or slag spring generated in front of the blast tuyere from the tuyere during operation. The blast furnace operating method is characterized in that the raceway in front of the tuyere is secured by destroying or melting it.