JP2684945B2 - Ash removal method on the inner surface of blast furnace tuyere - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for removing ash attached to the inner surface of a tuyere when a powdered fuel such as pulverized coal or coke powder is blown from the tuyere of a blast furnace.

[0002]

2. Description of the Related Art In recent years, in the operation of a blast furnace, a method of blowing powdered fuel such as pulverized coal or coke powder from a blast tuyere has been widely put into practical use for the purpose of reducing the fuel consumption rate and stabilizing the furnace condition. ing. As shown in FIG. 2, the conventional method of blowing powder fuel from a blast tuyere penetrates a wall of a hot air blowing pipe 23 connected to a blast tuyere 22 having an insulating ring 21 for blowing hot air to a blast furnace on an inner surface. And hot air blowing pipe 23
From the powder fuel injection nozzle 24 facing inside, pulverized coal,
It is common to blow powder fuel such as coke powder into the furnace.

In the method of blowing powder fuel by the method shown in FIG. 2, ash contained in pulverized coal, coke powder or the like in an amount of about 5 to 15% is melted by combustion heat or the like, and the inner peripheral surface of the blower tuyere 22. Alternatively, there is a problem that the adhered ash 25 accumulates on the inner peripheral surface of the heat insulating ring 21 and grows to narrow the air passage, and it also makes it difficult to blow hot air and fuel from the tuyere. As a measure to prevent the deposition of ash on the inner surface of the blast furnace tuyere or the inner surface of the heat insulating ring, the conventional method such as changing the injection position and injection angle of the powder fuel injection nozzle has been taken. Alternatively, a method has been proposed in which a high-pressure gas with a wind velocity of 50 m / sec or more is blown onto the inner surface of the tuyere (Japanese Patent Laid-Open No. 1-259110).
In addition, as a method of preventing powder clogging on the inner surface of the tuyere that blows the refining gas into the refining furnace, the end of the suction tube inserted from the furnace outer end of the tuyere to the inside of the tuyere should be covered with the powder clogging part. And connect the other side of the suction tube to the suction source (Japanese Patent Laid-Open No. 5-58200).
9-126712) has been proposed.

[0004]

The method of changing the blowing position and the blowing angle of the powder fuel blowing nozzle is as follows.
It has not reached the point of eliminating the adhesion of ash. Further, the method disclosed in Japanese Patent Laid-Open No. 1-259110 has a wind speed of 50.
Since high-pressure gas of m / sec or more is blown, there is a problem that smooth operation is hindered. Further, JP-A-59-12
The method disclosed in Japanese Patent No. 6712 prevents powder clogging on the inner surface of the tuyere of the refining furnace, and cannot be applied to ash removal on the inner surface of the blast furnace tuyere or the heat insulating ring. is there.

An object of the present invention is to provide a method for effectively removing the ash content adhering to the inner peripheral surface of the blown tuyere or the inner peripheral surface of the heat insulating ring generated by the injection of the powdered fuel from the tuyere of the blast furnace. is there.

[0006]

Means for Solving the Problems The present inventors have conducted various tests and studies to achieve the above object. As a result, it was clarified that the ash content adhering to the inner peripheral surface of the blown tuyere or the inner peripheral surface of the heat insulating ring can be effectively removed by driving a solid ball from the outside end of the furnace of the tuyere into the interior of the tuyere, and reached the present invention. did.

That is, the present invention relates to a method for removing ash deposits on the inner peripheral surface of a blast tuyere or the inner peripheral surface of a heat insulating ring, which is generated by blowing powder fuel from the blast furnace blast tuyere.
A method for removing ash from the inner surface of a tuyere of a blast furnace characterized by driving a solid ball into the tuyere from the outer end of the tuyere.

[0008]

In the present invention, solid spheres are driven into the tuyere from the outside end of the tuyere, so that the ash adhering to the inner surface of the blower tuyere or the inner surface of the heat insulating ring is removed by the driven solid spheres. Then, it is loaded into the furnace together with the solid balls. The solid spheres used are not particularly limited as long as they can be melted or discharged as slag in the blast furnace such as steel balls, ceramic balls, slag balls, etc., but steel balls are suitable. Also, the implantation of solid balls from the outer edge of the tuyere is
It is effective to provide a high pressure gas such as nitrogen gas and variably set the traveling direction of the solid spheres.

[0009]

【Example】

Example 1 FIG. 1 illustrates a method of driving a solid ball into the tuyere of the blast furnace according to the present invention. The hot air blowing pipe 2 connected to the tuyere 1 has a bun cover 3 at the rear end in each T-shaped direction. On-off valve 4,
A flexible hose 7 having 5 and 6 is connected, a nitrogen gas blowing pipe 8 is connected to the opening / closing valve 4, the opening / closing valve 5 is opened, and a solid ball 9 is fed into the flexible hose 7 to open / close the valve 5.
And then open the on-off valve 6 and then open the on-off valve 4 into the flexible hose 7 to inject the nitrogen gas blowing pipe 8
When nitrogen gas is blown from the solid ball 9 into the furnace through the tuyere 1, the flexible hose 7 makes it possible to change the traveling direction of the solid ball 9. In addition, 10 is a heat insulating ring mounted on the inner surface of the tuyere 1, and 11 is an adhered ash content on the inner peripheral surface of the tuyere 1 or the inner peripheral surface of the heat insulating ring 10.

With the above construction, the on-off valve 5 is opened, the solid ball 9 is fed into the flexible hose 7, the on-off valve 5 is closed, and then the on-off valve 6 is opened, and then the on-off valve 4 is opened. When nitrogen gas is blown into the flexible hose 7 through the nitrogen gas blowing pipe 8, the solid spheres 9 drive the tuyere 1 into the furnace by the high pressure nitrogen gas.
During the process, the solid sphere 9 comes into contact with the adhered ash 11 on the inner peripheral surface of the tuyere 1 or the inner peripheral surface of the heat insulating ring 10 and removes it by impact. Further, since the moving direction of the solid ball 9 is made variable by the flexible hose 7, the adhered ash 11 on the inner peripheral surface of the tuyere 1 or the inner peripheral surface of the heat insulating ring 10 can be removed over the entire circumference.

Example 2 In a blast furnace having an internal volume of 2700 m ³ , the ash content of 7.
Pulverized coal containing 7% was blown, and the method shown in Fig. 1 was applied from the tuyere where the ash content adhered to the inner surface of the tuyere or the inner surface of the heat insulating ring to a thickness of 30 mm. While changing the traveling direction of the steel ball with a flexible hose, blow with a nitrogen gas at a pressure of 7 kg / cm ² G to 50
It was driven into an individual furnace and the removal state of adhering ash was investigated. As a result, the adhered ash adhering to the inner peripheral surface of the tuyere or the inner peripheral surface of the heat insulating ring was removed to a thickness of 5 mm.

[0012]

As described above, according to the method of the present invention, it is possible to remove the ash content adhering to the inner peripheral surface of the tuyere or the inner peripheral surface of the heat insulating ring, which is generated by the injection of the solid fuel from the tuyere of the blast furnace. It is effective for stable operation of blast furnace and reduction of pig iron cost.

[Brief description of the drawings]

FIG. 1 is a vertical cross-sectional view illustrating a method of driving a solid ball into the tuyere of a blast furnace according to the present invention.

FIG. 2 is a vertical sectional view showing a conventional solid fuel injection method.

[Explanation of symbols]

 1, 22 Tuyere 2, 23 Hot air blowing pipe 3 Manju cover 4, 5, 6 Open / close valve 7 Flexible hose 8 Nitrogen gas blowing pipe 9 Solid ball 10, 21 Insulation ring 11, 25 Attached ash content 24 Powder fuel blowing nozzle

Claims (1)

(57) [Claims] 1. A method for removing ash content adhering to the inner peripheral surface of a blast tuyere or the inner peripheral surface of a heat insulating ring generated by blowing powder fuel from the blast furnace blast tuyere, from the furnace outer end of the tuyere to the inside of the tuyere. A method for removing ash from the inner surface of the tuyere of a blast furnace, characterized by driving a solid ball into the blast furnace.