JP2986244B2 - Pulverized coal injection lance for blast 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 pulverized coal injection lance for a blast furnace, which can improve the productivity of the blast furnace by blowing pulverized coal into the blast furnace from the tuyere of the blast furnace.

[0002]

2. Description of the Related Art Conventionally, in a blast furnace, finely pulverized coal (hereinafter referred to as pulverized coal) has been blown into a furnace from a blowing tuyere to improve productivity and economic efficiency. There are various types of pulverized coal injection lances.
No. 06 discloses a method of feeding pulverized coal from a tuyere that blows hot air into a furnace or a lance that protrudes and inserts a tip into a blow pipe, and blows it from the blast furnace tuyere with hot air. Using a double pipe consisting of a pipe and an outer pipe, the pulverized pulverized coal supplied from the inner pipe of the lance, and the oxygen concentration of the air supplied from the outer pipe according to the properties and amount of pulverized coal Are controlled and burned, and blown into a blast furnace by hot air is disclosed.

[0003]

However, according to the above prior art, when the amount of pulverized coal blown is large, even if the oxygen concentration of the combustion air supplied from the outer tube of the double tube lance is controlled. However, it becomes impossible to improve the pulverized coal combustion rate. This is because, with increasing of the pulverized coal blown amount, the ratio i.e. combustion rate of pulverized coal C is CO or CO ₂ is reduced, the blowing amount is limit 160 kg / t · pig iron,
At 160 kg / t pig iron, the combustion rate is about 60%. Therefore, when injecting 160 kg / t pig iron or more, pulverized coal is discharged from the blast furnace without being consumed by indirect reduction by combustion in the raceway formed in front of the tuyere and gasification in the blast furnace or direct reduction by solid C. Scattered to waste.

The present invention has been made in view of such circumstances, and an object of the present invention is to provide a pulverized coal injection lance for a blast furnace capable of injecting a large amount of pulverized coal with a higher combustion rate than that of the prior art. It is assumed that.

[0005]

The present inventors conducted a pulverized coal combustion experiment in a combustion furnace assuming the combustion of pulverized coal in a raceway in front of the tuyere. It was found that the pulverized coal combustion rate of the part was extremely lower than that of the peripheral part. This is because the combustion rate decreases because the flow velocity in the central portion is large, the residence time is short, and the concentration of pulverized coal is high in the central portion.

The present invention focuses on lowering the pulverized coal concentration at the center of pneumatic pulverized coal injected from a double lance and dispersing the pulverized coal throughout the pulverized coal to obtain uniform results. The gist of this is as follows. That is, the present invention comprises a double pipe, a pulverized coal blast for the blast furnace which injects pneumatic pulverized coal from the inner pipe, and cooling air for the inner pipe from the outer pipe, at the tip of the outer pipe of the lance. In the provided mounting seat, a plurality of U-shaped notches are arranged on the outer periphery at the tip end portion at equal intervals on the outer periphery, and a base opposed to the pulverized pulverized coal is provided in the center of the inside with a cone-shaped diffuser, A pulverized coal injection lance for a blast furnace, wherein a coupling having a straight flow path and a diffusion flow path formed at the rear of the diffuser is detachably attached.

In the present invention, a U-shaped notch is not provided, and a base having a cone-shaped base opposed to the pulverized coal pulverized coal is provided in the center of the inside, and a spiral flow path is formed at the rear of the diffuser. The coupling may be detachably mounted.

[0008]

[Operation] Since the present invention has the above configuration, the pulverized pulverized coal flowing in the inner pipe of the double pipe has a higher concentration of pulverized coal in the center portion than in the peripheral portion. It is diffused to the peripheral part by a cone-shaped diffuser provided to face the pneumatic pulverized coal. In this way, the pulverized coal diffused from the central portion to the peripheral portion passes through a plurality of U-shaped notches or spiral flow channels arranged on the outer periphery of the outer tube tip portion, and is scattered throughout and homogenized. Therefore, the combustion rate of pulverized coal is improved.

[0009]

Embodiments of the present invention will be described below with reference to the drawings. 1A and 1B show one embodiment of the present invention,
The double tube lance 3 is composed of a concentric inner tube 1 and an outer tube 2. In the present invention, a mounting seat 4 is provided at the tip of the outer tube 3, and a female screw 5 is provided inside the mounting seat 4. Has been cut.

On the other hand, a plurality (4 in the drawing)
) U-shaped notches 6 are arranged at equal intervals on the outer periphery, and a male screw 9 is provided on the coupling 8 having a base 7 provided with a cone-shaped diffuser 7 at the center of the inside facing the pulverized pulverized coal. It is provided. The male screw 9 of the coupling 8 is screwed and integrated with the female screw 5 provided inside the mounting seat 4.
The conical diffuser 7 and the coupling 8 are integrated by welding through a straight connecting plate 10.

The operation of the double tube tuyere 3 according to the present invention will be described. Pneumatic pulverized coal passes through the inner pipe 1 of the double pipe lance 3, and cooling air is supplied from the outer pipe 2. At this time, the pulverized pulverized coal is blown into the mounting seat 4 through the inner pipe 1 while the concentration in the central portion is high and the concentration in the peripheral portion is low, and is mixed with the air supplied from the outer tube 2. Become. The pulverized pulverized coal mixed with the cooling air in this manner collides with the cone-shaped base of the diffuser 7 provided inside the coupling 8 and is diffused outward from the U-shaped notch 6. And
It is divided into a member that goes straight through the gap between the diffuser 7 and the coupling 8, and a portion where the pulverized coal concentration is locally high is eliminated by the dispersion.

Next, a case where the double tube tuyere 3 of the present invention is applied to a combustion experimental furnace 11 approximated to the tuyere portion of an actual blast furnace will be described with reference to FIG. Blow pipe 12-1100 ~
Hot air of 1200 ° C. is sent to the combustion experimental furnace 11 through the tuyere 14. On the other hand, the double tube lance 3 is inserted into the lance guide tube 13 provided at an angle to the blow pipe 12 connected to the combustion experimental furnace 11, and the mounting seat of the double tube lance 3 is provided at the center of the tuyere 14. A coupling 8 mounted via 4 protrudes. Then, pulverized coal is supplied from the pulverized coal supply pipe 15 to the inner pipe 1 of the double pipe lance 3 by carrier air, and cooling air is supplied to the outer pipe 2 from the air supply pipe 16.

In this way, the pulverized coal flows in the inner pipe 1 of the double pipe lance 3, and the cooling air flows in the outer pipe 2 and the pulverized coal blown out into the mounting seat 4 mixes with the cooling air. The diffuser 7 provided inside the coupling 8 as described above
Are diffused outward from the U-shaped notch 6 by colliding with the cone-shaped base portion, and those that go straight through the gap between the diffuser 7 and the coupling 8. After blowing out from the coupling 8 in this way, the temperature in the tuyere 14 is 1100 to 1200 ° C.
Combustion Experimental Furnace 11
Since the air is blown into the inside, the pulverized coal concentration becomes uniform, and an improvement in combustibility is achieved. At this time, the degree of dispersion of the pulverized pulverized coal is mainly determined by the cone angle θ of the cone-shaped diffuser 7 (see FIG. 1A).

As a result, the burning rate of pulverized coal at the furnace core in the experimental combustion furnace 11 was improved, and the burning rate in the direction perpendicular to the axis became substantially flat, and the overall burning rate was improved. In addition, according to the conventional double pipe lance, pulverized coal is 160 kg / t
The combustion rate at the time of injection was about 60% in total, but according to the double-tube lance of the present invention, pulverized coal 200 kg / t pig iron,
Even at the equivalent of blowing, it is 70% in total, 160kg / t
・ Pig iron exceeded the equivalent time.

In the above, the combustion experimental furnace has been described.
Even when pulverized coal of about / t · pig iron is injected, the pulverized coal can be used with a good combustion rate without being discharged to the outside of the system. 2 (a) and 2 (b) show another embodiment of the present invention, wherein the female screw 5 is cut inside the mounting seat 4 provided at the tip of the outer tube 3 in the above embodiment. However, a U-shaped notch is not provided on the outer periphery of the distal end portion of the coupling 8, but a diffuser 7 having a cone-shaped base at the center of the inside facing the pulverized pulverized coal is provided. A plurality of spiral wings 17 (4 in the drawing) are provided between the rear of the body 7 and the coupling 8.
Individual pieces) and welded into an integrated structure. A male screw 9 is cut outside the coupling 8, and the male screw 9 is detachably attached to the female screw 5 of the mounting seat 4 as in the above-described embodiment.

The pulverized pulverized coal flowing through the inner pipe 1 of the double-pipe lance 3 is mixed with cooling air supplied from the outer pipe 2, then collides with the cone-shaped base, and is formed by the spiral blade 17. By passing through the plurality of spiral passages, the pneumatic coal pulverized coal is given a swirling motion. At the stage where the pulverized coal is spouted from its tip, the suppression of the centrifugal force is lost, so that the coal is diffused outward. The degree of dispersion due to the turning is mainly determined by the twist angle of the spiral blade 17. Thus, the portion where the pulverized coal concentration locally increases due to the diffusion action as described above is eliminated, and the improvement of the pulverized coal combustion rate is achieved in the same manner as in the above embodiment.

In the above-described embodiment, the attachment and detachment of the mounting seat 4 of the double pipe lance 3 and the coupling 8 has been described. However, other appropriate attachment / detachment means such as a bayonet may be used.

[0018]

As described above, according to the present invention, the pulverized coal blown into the blow pipe or the tuyere from the double pipe lance is uniformly diffused without locally increasing the concentration, so that the blast furnace Improvement of the combustion rate of the pulverized coal blown into the furnace together with hot air from the tuyere is achieved. In addition, when the coupling or the diffuser is worn out and hinders the pulverized coal injection, replacement is easy, and the pulverized coal can be always stably injected.

[Brief description of the drawings]

FIG. 1 shows an embodiment of the present invention, wherein (a) is a longitudinal sectional view,
(B) is a transverse cross-sectional view showing AA of FIG.

FIGS. 2A and 2B show another embodiment of the present invention, wherein FIG. 2A is a longitudinal sectional view, and FIG. 2B is a plan view taken along the line AA of FIG.

FIG. 3 is a longitudinal sectional view when the present invention is applied to an experimental combustion furnace.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Inner tube 2 Outer tube 3 Double tube lance 4 Mounting seat 5 Female screw 6 U-shaped notch 7 Conical diffuser 8 Coupling 9 Male screw 10 Connection plate 11 Combustion test furnace 12 Blow pipe 13 Lance guide tube 14 Tuyere 15 Pulverized coal supply pipe 16 Air supply pipe 17 Spiral wing

Claims (2)

(57) [Claims] 1. A blast furnace pulverized coal lance for spraying pulverized pulverized coal from an inner pipe and cooling air for the inner pipe from an outer pipe at a tip of the outer pipe of the lance. In the provided mounting seat, a plurality of U-shaped notches are arranged on the outer periphery at the tip end portion at equal intervals on the outer periphery, and a base opposed to the pulverized pulverized coal is provided in the center of the inside with a cone-shaped diffuser, A pulverized coal injection lance for a blast furnace, wherein a coupling having a straight passage and a diffusion passage formed at the rear of the diffuser is detachably attached. 2. A diffuser having a cone-shaped base opposed to the pulverized pulverized coal is provided in the center of the inside without providing a U-shaped notch,
2. A pulverized coal injection lance for a blast furnace according to claim 1, wherein a coupling having a spiral flow path is detachably attached to a rear portion of the diffuser.