JPH0416522B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION [Industrial Application Field] This invention relates to a method for blowing a plurality of types of powder into a blast furnace tuyere.

[Conventional technology]

Generally, in blast furnace operation, various powders are injected in order to properly manage the factors of reactions in the furnace or as an alternative fuel to coke.
A conventional blowing lance for blowing powder into a blast furnace is shown in FIG. 3.

That is, 1 is a blow pipe, and a tuyere 2 is formed at the tip of the blow pipe, and the tip of the tuyere 2 faces into the blast furnace 9. The tip of a lance 3 faces inside the blow pipe 1 by penetrating the pipe wall, and powder is blown out from the lance 3 into the tuyere 2. The blown powder is then blown into the blast furnace 9 through the tuyere 2 together with the gas (hot air) passing through the blow pipe 1. 6 is a guide pipe between the blow pipe 1 and the lance main body 3.

However, when blowing powder into the blast furnace 9 using such a lance 3, various in-furnace adjustment factors must be adjusted, such as adjusting the gas inside the blast furnace 9, adjusting the components of pig iron, adjusting the slag components, and reducing fuel costs. When performing two or more types at the same time, since the lance 3 is made of a single tube, only one type can be performed.

Therefore, for example, when blowing pulverized coal and iron ore powder into the blast furnace 9 at the same time, as shown in FIG.
There is a method in which two lances 3 are faced into the blow pipe 1 from opposite positions and the powder is blown individually from each lance 3, or as shown in Fig. 5, the tips of two lances 3 are A method has been proposed in which powder is similarly blown into the pipe 1 while being shifted in the longitudinal direction of the pipe 1.

[Problem that the invention seeks to solve]

However, when the tip positions of the lances 3 are placed opposite each other as shown in Fig. 4, the discharged dissimilar powders collide and scatter, making it impossible to blow each powder uniformly into the blast furnace 9. There is a problem.

Furthermore, as shown in FIG. 5, when the tips of the lances 3 are shifted from each other, there is a problem in that the tips of the lances 3 closer to the inside of the blast furnace 9 are damaged due to the discharge of powder from the lances 3 farther from the inside of the blast furnace 9. There is.

This invention was made by paying attention to the problems of the prior art, and it uses two or more types of powder,
The purpose is to blow smoothly and without damaging the lance or blow pipe.

[Means for solving problems]

This invention involves protruding the tip of a lance into the blowpipe facing the tuyere of a blast furnace, and blowing multiple types of powder from the tip of the lance into the gas passing through the blowpipe toward the furnace interior. In the method of blowing powder into the furnace together with gas, the lance is composed of multiple tubes to reduce the influence of heat on the inner tubes than on the outer tubes, and to reduce the influence of heat on the powder whose particles are relatively hard. Powders with relatively soft particles are blown into the blow pipe from the inner pipe, and powder with relatively soft particles is blown into the blow pipe, with the soft powder surrounding the hard powder.

[Effect]

Powder with relatively hard particles is discharged from the inner tube, which is less affected by heat, so that the tube is less likely to be worn down by the hard particles. In addition, the powder discharged from the lance has hard particles on the inside surrounded by soft particles on the outside, which prevents the hard particles from coming into direct contact with the blow pipe. Therefore, it is possible to prevent the blow pipe from being worn out. Then, the discharged powder is blown into the blast furnace along with the gas flowing through the blow pipe, with the powder particles near the center being hard and the outer powder particles being soft.

[Example] Figures 1 and 2 are diagrams showing an example of this invention. Here, 1 is a blow pipe, and a lance 3 passes through the pipe wall of the blow pipe via a guide pipe 6. The tip of the lance 3 faces near the center of the blow pipe 1.

In this embodiment, the lance 3 has an inner tube 3a and an outer tube 3.
Both pipes 3a and 3b are connected to separate supply pipes 5a and 5b, and on-off valves 4a and 4b are connected to each other.
5a are individually connected to each other. supply pipe 5a,
5b are each connected to a powder hopper,
Hard powder particles are supplied to the inner tube 3a, and the outer tube 3a is supplied with hard powder particles.
Soft powder of particles is supplied to b. Here, the inner tube 3a is supported by the outer tube 3b by a mechanism not shown so that it is always located at the center of the outer tube 3b. 6 is a guide tube between the blow pipe 1 and the outer tube 3b.

Therefore, the inner tube 3a and the outer tube 3 that constitute the lance 3
Different types of powder are discharged into the blow pipe 1 from b. As the powder, powders for blowing into the blast furnace 9 such as pulverized coal, iron ore powder, iron powder, limestone powder, and collected dust are used, and when two of these powders are injected with the lance 3, Of the two types of powder, the one with harder particles is blown into the inner tube 3a, and the one with softer particles is blown into the outer tube 3b.

As a result, the hard and abrasive powder that is blown in from the inner pipe 3a is removed from the outer pipe 3a.
Immediately after the discharge port of the lance 3, the powder with soft particles and low abrasiveness is blown in from b.
It is blown into the blow pipe 1 while being surrounded on the outside. For this reason, hard particles of powder rarely come into direct contact with the blow pipe 1 or the tuyeres.
The blow pipe 1 also does not wear out the inner surface of the tuyere.

In addition, since the inner tube 3a is insulated by the outer tube 3b and the space between the outer tube 3b and the inner tube 3a, the temperature does not become too high even when the high temperature gas passes through the blow pipe 1. Even if hard particle powder is passed through the inner tube 3a, abrasion of the powder is suppressed.

The inventors used a lance 3 in which the diameter of the inner tube 3a was 25 mm and the diameter of the outer tube 3b was 40 mm, and conducted the following experiments in order to reduce the amount of coke input into the blast furnace and to adjust the composition of pig iron. Ivy. That is, iron ore powder was passed through the inner tube 3a, and carbonaceous material powder was passed through the outer tube 3b, and these were discharged into the blow pipe 1 and blown into the blast furnace. As a result, since the inner tube 3a was thermally protected by the outer tube 3b, it was not heated much and the powder could be smoothly blown into the inner tube 3a without being worn out.

Furthermore, since the abrasive iron ore powder discharged from the inner pipe 3a is surrounded by the soft-grained carbonaceous powder discharged from the outer pipe 3b, the blow pipe 1 and the tuyere without abrading the inner surface of the
It has become possible to continue smooth blowing over a long period of time.

In the above embodiments and experiments, the lance 3 was made of a double pipe, but it goes without saying that the lance 3 may be made of three or more pipes and three or more types of powder may be blown into the lance at the same time.

〔Effect of the invention〕

As explained above, according to the present invention, powder with relatively hard particles is discharged from the inner tube which is less affected by heat, so the tube does not reach a high temperature and is therefore subject to wear and tear due to the hard particles. less likely to happen. On the other hand, since relatively soft powder particles pass through the outer tube, which is affected by heat, there is less wear and tear caused by the powder.

In addition, the powder discharged from the lance has hard particles on the inside surrounded by soft particles on the outside, which prevents the hard particles from coming into direct contact with the blow pipe. Therefore, it is possible to prevent the blow pipe and tuyere from being worn out. Thus, according to the present invention, wear and tear on the lance, blowpipe, and tuyere can be prevented, and powder can be blown smoothly and stably over a long period of time.

[Brief explanation of drawings]

FIG. 1 is a sectional view of one embodiment of the present invention, FIG. 2 is a sectional view taken along the line -- in FIG. 1, and FIGS. 3, 4, and 5 are sectional views of the prior art. 1...Blowpipe, 3...Lance, 3a...
Inner tube, 3b...outer tube.

Claims (1)

[Claims] 1 The lance tip protrudes into the blow pipe facing the tuyere of the blast furnace, and multiple types of powder are blown from the lance tip into the gas passing through the blow pipe towards the furnace. In the method of blowing powder into the interior, the lance is configured with multiple tubes so that the influence of heat on the inner tube is less than on the outer tube, and the powder with relatively hard particles is
Blow from the inner pipe, which is less affected by heat, and blow powder with relatively soft particles from the outer pipe, so that the soft powder surrounds the hard powder, and each powder is put into the blow pipe. A method for blowing powder into a blast furnace.