JPS61153216A - Method for blowing powder into blast furnace - Google Patents

Abstract

PURPOSE:To blow smoothly plural powders into a blast furnace without wearing the lance and blow pipe of the furnace by blowing respectively the powder of relatively hard particles through an inside pipe which is less affected by the heat of the lance projected into the blow pipe facing the tuyere of a blast furnace and the powder of relatively soft particles through an outside pipe. CONSTITUTION:The powder of the relatively hard particles is blown into the blast furnace through the inside pipe 3a constituting the lance 3 and the powder of the relatively soft particles is blown through the outside pipe 3b respectively to near the center of the blow pipe 1. The hard and highly wear resistant powder discharged from the pipe 3a is enclosed by the powder of the relatively soft and low wear-resistant particles blown through the outside pipe 3b and is blown in this state into the blast furnace from the pipe 1. The wear of the blow pipe and tuyere by these plural powders is thus prevented and the smooth and stable blowing of the powder is made possible over a long period of time.

Description

DETAILED DESCRIPTION OF THE INVENTION This invention relates to a method for blowing a plurality of types of powder into a blast furnace from a blast furnace tuyere.

BACKGROUND OF THE INVENTION Generally, in blast furnace operations, various powders are injected in order to properly manage the factors of reactions within the furnace or as alternative fuels for coke.

A conventional blowing lance for blowing powder into a blast furnace is shown in FIG. 3.

That is, ``■'' 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. Inside the blow pipe 1, the tip of the lance 3 faces through the pipe wall,
Powder is blown out from this 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, it has been possible to perform only type L.

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

[Problem that the invention seeks to solve]

However, when the tip positions of the lances 3 face each other as shown in Fig. 4, the discharged dissimilar powders collide with each other 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 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 in view of the problems of the prior art, and aims to blow two or more types of powder 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 blast furnace, blowing multiple types of powder from the tip of the lance into the gas passing through the blowpipe toward the furnace, and converting the powder into gas. In the method of blowing powder into the furnace, the lance is constructed with multiple tubes to reduce the influence of heat on the inner tube than on the outer tube, and to reduce the influence of heat on the powder with relatively hard particles. Each powder is blown into the blow pipe by blowing from a small inner pipe and blowing powder having relatively soft particles from an outer pipe so that the powder having soft particles surrounds the powder having hard particles.

[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 by the gas flowing through the blow pipe, with the powder particles near the center being hard and the outer powder particles being soft.

〔Example〕

FIG. 1.2 is a diagram showing an embodiment 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 blowpipe l.

In this embodiment, the lance 3 is composed of a coaxial double pipe consisting of an inner pipe 3a and an outer pipe 3b, and both pipes 3a and 3b are connected to separate supply pipes 5a and 5b, respectively, and an on-off valve 4a.

5a are individually connected to each other. Supply pipe 5a.

- 5b are each connected to a powder hopper, and the inner tube 3a is supplied with hard powder particles, and the outer tube 3b is supplied with soft powder particles. 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.

Thus, different types of powder are discharged into the blow pipe 1 from the inner tube 3a and outer tube 3b that constitute the lance 3. As the powder, powders for blowing into the blast furnace 9 such as pulverized coal, iron ore powder, 5 iron powders, 2 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 powder with hard particles and high abrasiveness blown in from the inner pipe 3a is replaced by the powder with soft particles and low abrasiveness blown in from the outer pipe 3b, from immediately after the discharge port of the lance 3. , is blown into the blow pipe 1 while being surrounded on the outside. For this reason, although hard powder particles rarely come into direct contact with the blow pipe 1 or the tuyere, 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 a powder of hard particles is passed through it, abrasion of the powder is suppressed.

The inventors set the diameter of the inner tube 3a to 25 mm, and the diameter of the outer tube 3b to 4 mm.
Using lance 3 with a diameter of 0 mm, the following experiment was conducted in order to reduce the amount of coke input into the blast furnace and to adjust the composition of pig iron. 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, the powder could be smoothly blown into the inner tube 3a without being heated or worn out.

In addition, the abrasive iron ore powder discharged from the inner pipe 3a is surrounded by soft-grained carbonaceous powder discharged from the outer pipe 3b. It is now possible to continue smooth blowing over a long period of time without causing wear.

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 that tube does not reach a high temperature and is therefore worn out by the hard particles. There will be fewer things. 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.
Since direct contact of the hard particle powder with the blow pipe is suppressed, it is possible to prevent the blow pipe and the slats from being worn out.

Thus, according to the invention, the lance, blowpipe,
This has the effect of preventing wear and tear on the lining and allowing smooth and stable powder blowing over a long period of time.

[Brief explanation of drawings]

FIG. 1 is a sectional view of an embodiment of the present invention, FIG. 2 is a sectional view taken along line nn in FIG. 1, and FIGS. 3, 4, and 5 are sectional views of the prior art. 1...Blowpipe, 3...Lance, 3a...Inner pipe, 3b...Outer pipe.

Claims (1)

[Claims] The tip of the lance protrudes into the blowpipe facing the tuyere of the blast furnace, and multiple types of powder are blown from the tip of the lance into the gas passing through the blowpipe toward the furnace interior. In the powder blowing method, 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 transferred to the inner tube, which is less affected by heat. A blast furnace characterized in that powder having relatively soft particles is blown from an outer pipe, and each powder is blown into a blow pipe with the powder having soft particles surrounding the powder having hard particles. How to blow powder into.