JP2868941B2 - Tuyere powder injection method for vertical furnace - 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 injecting tuyere powder particles into a vertical furnace such as a blast furnace or a smelting reduction furnace having a multistage tuyere.

[0002]

2. Description of the Related Art In recent years, in the operation of a blast furnace, an operation of injecting powder and granules from a blast furnace tuyere has been carried out for the purpose of reducing pig iron cost by using inexpensive raw fuel and controlling hot metal components. Also in the operation of a so-called smelting reduction furnace using a vertical coke packed bed furnace, powdery iron ore or other metal oxide powder is generally blown from a tuyere as a raw material. As shown in FIG. 2, the powdery material is blown into the tuyere of the vertical furnace by inserting one powdery material blowing lance 13 for each tuyere from the blow pipe 9 connected to the tuyere 11. It is common. Also, in order to achieve a large amount of powder and granules, a tuyere is arranged in upper and lower stages, and powder and granules are blown from both upper and lower tuyeres (Japanese Patent Laid-Open No. 3-39407). Also, a method has been proposed in which two powder lances are arranged in each tuyere.

[0003] On the other hand, there is a method in which a powder and granule blowing lance is formed as a double pipe for rapid furnace adjustment, and oxygen is simultaneously blown from one pipe and carbonaceous material is blown from the other pipe. (JP-A-59-281
No. 093). Further, depending on the operating conditions, a part of the injected granular material becomes undissolved and may adhere to and grow on the tuyere tip or the like.
No. 4138).

[0004]

SUMMARY OF THE INVENTION When the amount of powder injected per one lance for blowing powder increases, or when the amount or temperature of hot air fluctuates (decreases), the injected powder can be used. Part of the granules may not be dissolved, and the undissolved granules may adhere and grow around the lance or tuyere tip of the granules. In severe cases, the blowing of the granules must be interrupted. In some cases.

In order to solve this problem, a technique for mechanically removing deposits on the tuyere tip is disclosed in Japanese Utility Model Laid-Open Publication No. Hei 3-14138. There is a problem that the adhering matter must be removed after the blowing is temporarily stopped. On the other hand, as a method of removing deposits without using a machine, it is possible to use a method in which oxygen is blown from one tube and granules are blown from another tube using a double tube lance. However, there is a problem that the structure of the lance becomes complicated, the weight of the lance becomes heavy, and it is difficult to handle.

[0006] It is an object of the present invention to provide a tuyere powder granule blowing method which solves these problems.

[0007]

According to the present invention, two powder lances are provided for each tuyere in a tuyere of a vertical furnace, and iron oxide powder is supplied from one of the powder lances. Alternatively, while injecting pulverized coal, the combustion supporting gas and the granular material are periodically and alternately switched and supplied from the other granular material blowing lance , and the tuyere powder granular material is injected into the vertical furnace. Is the way.

Here, the vertical furnace refers to a blast furnace or a smelting reduction furnace having a multistage tuyere. In addition, the iron oxide powder refers to a powder containing iron oxide, for example, iron ore powder, dust generated in a blast furnace, a converter, and a rolling process. The twisting gas refers to oxygen, oxygen-enriched air, and the like.

[0009]

According to the present invention, two powder lances are provided at each tuyere, and while one of the lances blows the powder, flammable gas such as oxygen is supplied from the other lance. With this configuration, it is possible to easily remove the particles attached to the tuyere tip by the combustible gas without interrupting the blowing of the particles.

[0010]

FIG. 3 is a block diagram showing a method of blowing tuyere powder in a smelting reduction furnace having two-stage tuyeres according to the present invention. After the iron oxide powder is stored in the iron oxide powder storage tank 1, it is put into the measuring hopper 3, and the flux is stored in the flux storage tank 2 and then put into the measuring hopper 3. In the weighing hopper 3, after weighing each of the iron oxide powder and the flux,
The two kinds of raw materials are mixed with the mixing gas 4. This mixture is introduced into the blowing tank 5.

In the blow tank 5, the inside of the tank is pressurized by a pipe (not shown) to fluidize the granular material in the blow tank 5. The fluidized granular material is sent out of the blowing tank 5 by the carrier gas 6, 7. The mixed powder of the iron oxide powder and the flux transported by the carrier gases 6 and 7 is ejected into the tuyere 11 from the powder blowing lances 13a and 13b,
It is blown into the smelting reduction furnace 14 from the upper tuyere 11 together with the hot air passing through the upper blow pipe 9 and the upper tuyere 11.
Here, the hot air is heated air or heated oxygen-enriched air. In addition, a pipe for supplying oxygen 8 is provided with carrier gases 6 and 7.
Is connected to the piping.

In this embodiment, as shown in FIG.
5 mm powder and granular material lances 13a and 13b are connected to upper tuyere 1
In general, two powders are blown from both lances and melted in the tuyere raceway 15. Monitor the blowing condition at the upper tuyere during powder and granular material blowing,
When the deposit 17 was generated, the supply of the granular material from one of the lances 13a was stopped, and at the same time, the carrier gas 6 was stopped, and oxygen 8 as a combustion supporting gas was supplied. At this time,
The blowing of the granular material into the other lance 13b was continued. As a result, melting of the deposit 17 and the blowing powder 16 is promoted,
It was confirmed that the deposit 17 was removed. Further, by periodically switching the supply of the granular material and the supply of oxygen, the generation of the deposit 17 can be prevented.

[0013]

According to the present invention, the powder and granules are blown from one of the powder and granule blowing lances respectively arranged in the tuyere.
Since the combustion supporting gas such as oxygen is supplied from the other side, it is possible to easily remove the deposits due to undissolved particles without stopping the blowing of the particles.

Further, by periodically switching between the injection of the granular material and the supply of oxygen, the dissolution of the granular material is promoted, so that not only the generation of the deposit can be prevented but also the large amount of the granular material can be blown. Become.

[Brief description of the drawings]

FIG. 1 is a cross-sectional view of a tuyere provided with two powder and granular lances used for carrying out the method of the present invention.

FIG. 2 is a view showing a conventional general tuyere powder granule injection.

FIG. 3 is a block diagram of a granular material blowing used in an embodiment of the present invention.

[Explanation of symbols]

 REFERENCE SIGNS LIST 1 Iron oxide powder storage tank 2 Flux storage tank 3 Measuring hopper 4 Mixing gas 5 Blow tank 6, 7 Carrier gas 8 Oxygen 9 Upper blow pipe 10 Lower blow pipe 11 Upper tuyere 12 Lower tuyere 13 Granule blowing lance 14 Melt reduction Furnace 15 Raceway 16 Granules 17 Deposits

Continuing from the front page (72) Inventor Seiko Kozi 1 Kawasaki-cho, Chiba-shi Kawasaki Steel Corp. Chiba Works (56) References JP-A-62-192509 (JP, A) JP-A-5-112806 (JP, A) (58) Field surveyed (Int. Cl. ⁶ , DB name) C21B 5/00 319-320 C21B 7/00 308-311

Claims (1)

(57) [Claims] 1. A tuyere of a vertical furnace is provided with two powder lances for each tuyere, and while one of the powder lances blows iron oxide powder or pulverized coal, the other lance. Switching between the combustion supporting gas and the granular material from the granular lance
A method for injecting tuyere powder and granular material into a vertical furnace, characterized in that it is supplied.