JPH11222612A - Lance for blowing pulverized coal to blast furnace and method for blowing pulverized coal to blast furnace - Google Patents

Abstract

PROBLEM TO BE SOLVED: To obtain the lance with which the high threshold blowing amt. of pulverized coal is obtd. and which does not give wise to the clogging by the pulverized coal by providing the front end of the lance consisting of a straight tubular body with a reflector for deflecting the direction of the pulverized coal stream flowing in the lance from the axial direction of the tubular body. SOLUTION: The front end of the lance 2 which is the straight tubular body is provided with the reflector 2 for deflecting the direction of the pulverized coal stream flowing in the lance 2 from the axial direction of the tubular body. The angle formed by the reflector 1 and the axial direction of the tubular body is so set that the highest combustion rate is attained by the blowing conditions of the pulverized coal. The pulverized coal stream ejected from, the front end of the lance 2 is reflected in a direction exclusive of the axial direction of the tubular body by the reflector 1 and, therefore, the dispensability of the pulverized coal 6 in the radial direction in a blow pipe is improved and the combustion rate is increased, by which the high threshold blowing amt. may be obtd. Since there is no branching part of the pulverized coal stream, the clogging of the lance does not arise.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a lance for injecting pulverized coal into a blast furnace, which has good dispersibility of injected pulverized coal and high flammability, and blowing pulverized coal into a blast furnace using the same. About the method of incorporation.

[0002]

2. Description of the Related Art In recent blast furnace operations, pulverized coal is injected from tuyeres for the purpose of extending the life of a coke oven and reducing the cost of hot metal, and the amount of injection is increasing. is there.

FIG. 7 is a sectional view showing a conventional method of injecting pulverized coal into a general blast furnace. In the conventional method of injecting pulverized coal into a blast furnace, a method for injecting one pulverized coal into a blow pipe 3 connected to a tuyere 4 provided on a blast furnace wall 7 has been used. The lance 2 is inserted, and the pulverized coal 6 is ejected from the lance 2 into the hot air flowing through the blow pipe 3 and is blown into the blast furnace.

FIG. 8 shows a conventional lance for injecting pulverized coal.
FIG. 3 shows a longitudinal section of an example. A straight pipe is used for the conventional pulverized coal injection lance 2, and pulverized coal 6 is ejected from the tip of the lance 2 in the axial direction of the lance 2.

[0005] The pulverized coal 6 spouted from the tip of the lance 2 burns while staying in the blow pipe 3 or the raceway 5. Instead, it is consumed as unburned char by furnace reaction. However, if unburned char exceeds the amount that can be consumed in the furnace reaction, the excess unburned char may be accumulated in the furnace or discharged as dust from the furnace top. Become. In such a state, the permeability of the furnace deteriorates due to the influence of the unburned char accumulated in the furnace, and the stable operation of the blast furnace cannot be performed. Therefore, the amount of unburned char generated is equal to the amount consumed in the furnace. The injection amount becomes the limit injection amount of pulverized coal.

When a conventional lance 2 as shown in FIG. 8 is used,
The pulverized coal 6 is ejected in the axial direction of the lance 2 and is not sufficiently diffused in the radial direction of the blow pipe 3, so that its dispersibility is poor.
Since a high combustion rate cannot be obtained, the critical injection amount is about 190 kg per ton of hot metal.

[0007] Recently, the present inventors have disclosed in Japanese Patent Application No. 9-3200.
At 84, a method capable of providing a plurality of injection ports at the tip of the pulverized coal injection lance to eject pulverized coal, improving the dispersibility in the blow pipe, increasing the combustion rate, and greatly improving the limit injection amount. Suggested.

FIG. 9 is a sectional view showing an example of a method of injecting pulverized coal into a blast furnace proposed in Japanese Patent Application No. 9-320084.

FIG. 10 shows a method of injecting pulverized coal into the blast furnace of FIG. 9 as viewed from the back. In this method, as shown in FIG. 9, two lances 2 provided with three pulverized coal injection ports 8 are provided.
In this method, the pulverized coal is injected into the blowpipe 3 connected to the tuyere 4 on the blast furnace wall 7 so that the pulverized coal is ejected so that the pulverized coal streams ejected from the respective outlets 8 of the lances 2 do not cross each other. is there. By injecting the pulverized coal in this way, as shown in FIG. 10, the pulverized coal can be sufficiently dispersed in the radial direction of the blow pipe 3, so that the combustion rate of the pulverized coal can be improved and 250 kg per ton of hot metal can be obtained. A high limit blowing amount can be obtained.

[0010]

However, according to the method described in Japanese Patent Application No. 9-320084, pulverized coal accumulates with time in the branch portion of a plurality of injection ports depending on the injection conditions, and the lance is closed. In some cases, pulverized coal injection became impossible.

The present invention has been made in order to solve such a problem, and a high pulverized coal limit injection amount can be obtained.
Another object of the present invention is to provide a lance for injecting pulverized coal into a blast furnace in which the lance is not blocked by pulverized coal and a method for injecting pulverized coal into a blast furnace using the lance.

[0012]

SUMMARY OF THE INVENTION The object of the present invention is to provide a blast furnace provided with a reflector at the tip of a lance formed of a straight tube, which deflects the direction of the pulverized coal flow flowing in the lance from the tube axis of the tube. It is solved by the pulverized coal injection lance.

At the tip of a lance consisting of a straight tube,
If a reflector is provided that diverts the direction of the pulverized coal stream flowing through the lance from the pipe axis direction of the pipe, the pulverized coal stream is reflected in a direction other than the pipe axis direction by this reflector, and the side without the reflector is provided. Is blown into the blowpipe without hitting the tube wall of the lance, so that the dispersibility of the pulverized coal in the radial direction of the blowpipe is improved, and a high limit blowing amount can be obtained. At this time, the angle formed between the reflector and the pipe in the pipe axis direction is appropriately set so that the combustion rate is maximized according to the pulverized coal blowing conditions. Further, since there is no branch portion of the pulverized coal stream, the lance does not clog.

The lance of the present invention is a lance having a reflector formed at the end of a straight pipe at a predetermined angle with respect to the pipe axis direction. The lance changes the direction of the pulverized coal flow by bending the end of the lance. Is different. In the latter lance, the pulverized coal flow is blown out along the pipe axis direction of the lance, so the dispersibility of the pulverized coal in the blow pipe is not very good, and the bent part has a closed system. Charcoal tends to accumulate and lances are likely to be blocked.

If the reflector can be removed, only this portion needs to be replaced in order to optimize the angle between the reflector and the tube axis depending on the pulverized coal blowing conditions.
Workability can be more simplified.

The reflector is preferably made of a ceramic having excellent heat resistance and abrasion resistance in order to withstand the impact of pulverized coal at high temperatures.

By inserting one lance according to the present invention into a blowpipe and injecting pulverized coal from the lance, the limit injection is higher than the conventional method of injecting pulverized coal into a blast furnace. Volume is obtained and no lance blockage occurs.

Further, when two or more lances of the present invention are inserted into a blowpipe and pulverized coal is ejected from each lance so that the pulverized coal streams ejected from each lance do not intersect, the pulverized coal in the blowpipe can be removed. Since the dispersibility is further improved, a higher limit blowing amount can be obtained.

When the lance of the present invention can be rotated around the pipe axis of the lance, the dispersibility of the pulverized coal in the blow pipe is further improved, and a higher combustion rate can be obtained.

[0020]

FIG. 1 is a longitudinal sectional view showing one embodiment of a lance for injecting pulverized coal into a blast furnace according to the present invention.

The lance 2 is a straight tube, and a reflector 1 is provided at the tip of the lance 2 to deflect the direction of the pulverized coal flow flowing in the lance 2 from the tube axis of the tube. The angle between the reflector 1 and the pipe axis in the pipe axis direction is set so that the combustion rate is maximized depending on the pulverized coal blowing conditions.

Since the pulverized coal stream ejected from the tip of the lance 2 is reflected by the reflector 1 in a direction other than the pipe axis direction, the dispersibility of the pulverized coal 6 in the blow pipe in the radial direction is improved, and the combustion thereof is performed. The rate increases, and a high limit blowing amount can be obtained. Further, since there is no branch portion of the pulverized coal stream, the lance does not clog.

FIG. 2 shows another embodiment of the lance for injecting pulverized coal into a blast furnace according to the present invention.

In this lance 2, a reflector chip 9 in which the reflector 1 is incorporated is attached to the tip of the lance 2 with a screw. Therefore, the angle between the reflector 1 and the tube body in the tube axis direction can be optimized only by replacing the reflector chip 9, so that the workability can be further simplified.

FIG. 3 is a cross-sectional view showing an embodiment of the pulverized coal injection method into a blast furnace according to the present invention.

FIG. 4 shows the method of injecting pulverized coal into the blast furnace of FIG. 3 as viewed from the back. As shown in FIG.
When the two lances 2 of FIG. 2 are inserted into the blowpipe 3 and pulverized coal is ejected from each lance 2 so that the pulverized coal streams ejected from each lance 2 do not intersect, as shown in FIG.
Since the pulverized coal 6 is dispersed in the radial direction in the blow pipe 3, a high limit blowing amount can be obtained.

Actually, the combustion rate of pulverized coal and the incidence of lance blockage according to the method of the present invention shown in FIGS. 3 and 4 are shown in FIGS.
Investigation was conducted in comparison with the method of Japanese Patent Application No. 9-320084 shown in FIG.

FIG. 5 shows the relationship between the distance from the lance tip and the combustion rate of pulverized coal. FIG. 6 shows the rate of occurrence of blockage of the lance.

According to the method of the present invention, Japanese Patent Application No. 9-320084
It can be seen that a high combustion rate similar to that of the above method is obtained, and that no lance blockage occurs.

[0030]

Since the present invention is constructed as described above, a high limit of pulverized coal injection can be obtained, and pulverized coal is injected into a blast furnace in which the lance is not blocked by the pulverized coal. A lance and a method of injecting pulverized coal into a blast furnace using the lance can be provided.

[Brief description of the drawings]

FIG. 1 is a longitudinal sectional view of an embodiment of a lance for injecting pulverized coal into a blast furnace according to the present invention.

FIG. 2 is a perspective view showing another embodiment of the lance for blowing pulverized coal into a blast furnace according to the present invention.

FIG. 3 is a cross-sectional view illustrating an embodiment of a method of injecting pulverized coal into a blast furnace according to the present invention.

FIG. 4 is a perspective view of the method of injecting pulverized coal into the blast furnace of FIG. 3 as viewed from the back.

FIG. 5 is a diagram illustrating a relationship between a distance from a lance tip and a combustion rate of pulverized coal.

FIG. 6 is a diagram showing the incidence of blockage of a lance.

FIG. 7 is a cross-sectional view illustrating a conventional method of injecting pulverized coal into a general blast furnace.

FIG. 8 is a longitudinal sectional view of an example of a conventional pulverized coal injection lance.

FIG. 9 is a cross-sectional view illustrating an example of a method of injecting pulverized coal into a blast furnace proposed in Japanese Patent Application No. 9-320084.

10 is a perspective view of the method of injecting pulverized coal into the blast furnace of FIG. 9 as viewed from the back.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Reflector 2 Pulverized coal injection lance 3 Blow pipe 4 Tuyere 5 Raceway 6 Pulverized coal 7 Blast furnace wall 8 Pulverized coal spout 9 Reflector chip

Claims (4)

[Claims] 1. A lance for injecting pulverized coal into a blast furnace having a reflector provided at the tip of a lance formed of a straight pipe at the tip of the lance to divert the direction of the pulverized coal flowing through the lance from the pipe axis direction of the pipe. . 2. The lance for injecting pulverized coal into a blast furnace according to claim 1, wherein the reflector is removable. 3. A method for injecting pulverized coal into a blast furnace in which one lance according to claim 1 or 2 is inserted into a blow pipe and pulverized coal is ejected from the lance. 4. When two or more lances according to claim 1 or 2 are inserted into a blowpipe and pulverized coal is ejected from each of the lances, the pulverized coal flow ejected from each of the lances intersects. How to inject pulverized coal into the blast furnace to avoid.