JPH07197114A - Coke packing layer type vertical smelting furnace - Google Patents

Abstract

PURPOSE:To remarkably reduce fuel ratio by arranging coke charging tubes at the intermediate position between raceways. CONSTITUTION:The coke 6 is supplied from a hopper 7 at the upper part of a furnace through plural charging tubes 8 to form a coke packing layer 1. Plural pieces of tuyeres 2. 2' for blasting are arranged at two steps of the upper and the lower parts in the peripheral direction at the lower part of the furnace. Powdery metallic oxide and slag-making agent for adjusting slag composition from the tuyeres 2 at the upper stage and oxygen-containing gas from the tuyeres at the lower stage are blown into the coke packing layer 1 to melt and reduce the metallic oxide. The coke charging tubes 8 are arranged so that this center axis becomes the intermediate position between the raceways 3 formed just at the front of the blasting tuyeres 2, 2' mutually adjoined in the circumferential direction of the furnace. By this method, the suitable contact between the high temp. gas and the molten material can be preserved.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention has a coke packed layer which is supplied and formed from the furnace top through a plurality of charging pipes, and hot air is blown from a plurality of tuyere provided circumferentially at the lower part of the furnace. The present invention relates to a vertical smelting furnace that melts and reduces metal oxide by blowing.

[0002]

2. Description of the Related Art A vertical coke packed bed type vertical smelting furnace is disclosed in, for example, Japanese Unexamined Patent Publication (Kokai) No. 57-198205. The powdery raw material is blown into the high temperature region inside the raceway formed in front of the tuyere, and the powdery raw material is melted and reduced by the heat inside the raceway and the carbon in the coke. At that time, since the melting of the powdery raw material precedes the reduction, the unreduced melt is dripped downward from the upper tuyeres. This unreduced melt is reduced to metal during the dropping in the coke packed bed, but the heat required for the reduction is the oxygen and enriched oxygen in the air blown from the lower tuyeres into the furnace. And is supplied from the gas generated by the combustion of coke.

By the way, the charging of coke into this furnace is
As disclosed in Japanese Patent Application Laid-Open No. 57-15307, conventionally, a coke charging pipe has been installed near the center of the furnace and near the wall of the furnace (see FIG. 3). This charging method is intended to keep the coke deposition surface in the furnace as flat as possible, to make the ventilation resistance uniform over the entire furnace surface, and to reduce the uneven flow of the gas flow in the furnace. Generally, in the vertical smelting furnace of the coke packed bed method, the gas flow flowing through the center of the furnace is strengthened in order to stably lower the coke in the furnace and reduce the heat load on the furnace body. The operation is performed so as to increase the amount of gas flowing through the center. However, in the coke charging method described in JP-A-57-15307, the heat load on the coke charging pipe installed at the center of the furnace top becomes very large, and there is a problem such as deformation of the charging pipe. However, there is a problem in that much cost is required for equipment maintenance.

Therefore, the present applicant has recently filed Japanese Patent Application No. 4-7.
No. 1764, a coke charging method as shown in FIG. 4 was proposed for the purpose of solving the problems caused by the technique described in JP-A-57-15307. It sets the central axis of the coke charging pipe so that it coincides with the center of the raceway formed by the lower blast tuyere, and by installing the charging pipe directly above the raceway, which is the coke consumption area, This is intended to stabilize the operation of the furnace by stabilizing the fall of the coke in the furnace.

However, this Japanese Patent Application No. 4-71764
Even if the coke charging pipe was installed just above the raceway as in No. 6, another problem as described below occurred. That is, when the coke flows out from the charging pipe to the surface of the coke packed layer in the furnace, the coke deposition state has a mountain shape with the lower end of the charging pipe as an apex. Since larger particles have a longer rolling distance, the particle size is smaller immediately below the charging pipe, and coke having a larger particle size tends to be deposited as the distance from the charging pipe increases in the horizontal direction. This situation is shown in the conceptual diagram of FIG. When viewed in a horizontal section, the coke grain size becomes smaller at the raceway position, and the coke grain size becomes larger as the distance from the raceway increases. Also,
Since the streamline of the coke falling in the furnace flows in the vertical direction substantially in accordance with the inclination of the furnace shaft, the coke particle size distribution in the horizontal cross section at the top of the furnace is preserved even in the lower part of the furnace. As a result, the gas generated in front of the tuyere flows upward in the furnace, but at that time, the gas has a large gas flow resistance in the region where the coke particle size is small, so that the gas selectively flows in the region where the coke particle size is large. . Therefore, if a charging pipe is installed directly above the raceway, the coke particle size near the tuyere is relatively small, and the coke particle size increases as it moves further away from the front of the tuyere in the horizontal direction. Flow more easily into the furnace center and into the area between adjacent tuyeres. As described above, in the vertical coke packed bed type vertical smelting furnace, when the powdered raw material blown from the upper tuyeres drips, the reduction proceeds by the heat supply from the high temperature gas generated in front of the lower tuyeres. Therefore, it is desirable that the gas generated in front of the lower tuyeres flows as vertically upward as possible and exchanges heat with the unreduced melt that drops from the front of the upper tuyeres.

However, in the coke charging method of Japanese Patent Application No. 4-71764, for the reasons explained above, the unreduced melt dripping from the front of the upper tuyeres and the gas generated in front of the lower tuyeres are effective. The heat cannot be exchanged, and the heat supplied from the lower tuyeres is not effectively used.

[0007]

SUMMARY OF THE INVENTION In view of such circumstances, the present invention provides a coke packed bed type vertical smelting furnace capable of stably descending coke in the furnace and operating with excellent thermal efficiency. Is intended.

[0008]

In order to achieve the above object, the inventor has used a cold scale model of a vertical smelting furnace, which is the object of the present invention, and has a gas flow in the furnace and a coke particle size distribution. We conducted tests and research on. At that time, in order for the gas generated in front of the lower tuyeres to rise effectively toward the upper tuyeres, it is effective to make the coke grain size in the vicinity of the tuyeres in the horizontal section relatively larger than that of the periphery. I knew it was. The present invention embodies this knowledge, and a coke packed layer formed by supplying coke from a hopper above the furnace through a plurality of charging pipes forms a coke packed layer formed in the lower circumferential direction of the furnace.
Of the multiple blast tuyeres installed in the stage, powdered metal oxide from the upper stage tuyeres and a slag component adjusting agent are blown, and an oxygen-containing gas is blown from the lower stage tuyeres to oxidize the metal. In a vertical coking bed type vertical smelting furnace that melts and reduces matter, the above-mentioned coke charging pipe is formed between the raceways formed immediately before the blast tuyere whose central axis is adjacent in the furnace circumferential direction. This is a coke packed bed type vertical smelting furnace characterized by being installed at a position.

[0009]

According to the present invention, a plurality of blowers are provided in the upper and lower two stages in the circumferential direction of the lower part of the coke packed bed formed by supplying the coke from the hopper above the furnace through the plurality of charging pipes. Of the tuyeres, powdered metal oxide from the upper tuyeres and slag-forming agent for adjusting the slag component, and oxygen-containing gas are blown from the lower tuyeres to melt and reduce the metal oxides. In the vertical smelting furnace of the layer method, the coke charging pipe,
Since the center axis was set at the middle position between the raceways formed immediately before the adjacent blast tuyeres in the circumferential direction of the furnace, the coke grain size in front of the lower tuyeres should be larger than that of the surrounding area. As a result, it becomes easy to contact the unreduced melt dropped from the front of the upper tuyeres with the hot gas generated in front of the lower tuyeres. As a result, the efficiency of heat exchange is significantly increased. The contents of the present invention will be described below with reference to FIGS.

FIG. 1 is an outline of a coke packed bed type vertical refining furnace according to the present invention. It is a vertical sectional view in Figure 1.
As is clear from (a), the charging pipe 8 has a structure for supplying the massive coke 6 accumulated in the hopper 7 on the furnace into the furnace, and the powdery raw material of the metal oxide is supplied from the upper tuyeres 2. It is blown in and the oxygen-containing gas is blown in from the lower tuyeres. In addition, as shown in FIG. 1 (b) of the plan view, the raceways 3 in front of the lower tuyeres 2 ′ have almost the same size in the vertical direction during normal operation. It is a hollow of. The point of the present invention is that the center axis of the doughnut-shaped region 12 including these raceways 3 is located at a position corresponding to the middle between adjacent raceways 3. It is to install an immigration pipe. as a result,
The coke charged has a particle size distribution as shown in FIG. 2 in the circumferential direction of the furnace. That is, the particle diameter immediately before the tuyere 2 is larger than that of the peripheral portion. The inventor was able to confirm the achievement of this particle size distribution by an experiment in a cold model (experimental conditions are shown in Table 1).

[0011]

[Table 1]

It should be noted that it is not necessary to explain that the lower end of the charging pipe is located above the raceway and above the furnace.

[0013]

Example A vertical smelting furnace according to the present invention having a production capacity of 140 T / D was manufactured, and molten iron was manufactured from a raw material of powdered iron oxide. Table 2 shows the operating conditions and the operating results at that time. As is clear from Table 2, due to the effect of the present invention, 140 T / D
Fuel ratio of 1120kg / t-meta
It was possible to operate at 1 l. On the other hand, when compared with the result (vertical example in Table 2) of the vertical smelting furnace in which the central axis of the conventional charging pipe is set to be substantially aligned with the central position of the raceway formed by each tuyere, the fuel ratio is There is a reduction of 50 kg / t-metal.

[0014]

[Table 2]

[0015]

As described above, according to the present invention, a plurality of air blower tuyeres are arranged in the upper and lower two stages in the circumferential direction of the lower part of the furnace. In a vertical smelting furnace in which a more powdery metal oxide and a slag-forming agent for adjusting the slag component are blown into the coke packed bed in the furnace, the furnace is simply modified by changing the arrangement of the coke charging pipes. It became possible to maintain proper contact between the hot gas and the melt inside, and it became possible to significantly reduce the fuel ratio during operation.

[Brief description of drawings]

FIG. 1 is a diagram showing an outline of a vertical coke packed bed type vertical smelting furnace according to the present invention, in which (a) is a longitudinal sectional view and (b) is a plan view.

FIG. 2 is a circumferential coke grain size distribution when the present invention is carried out in a cold model.

FIG. 3 is a vertical sectional view showing an outline of a conventional vertical smelting furnace.

FIG. 4 is a schematic view of a vertical smelting furnace applied for in Japanese Patent Application No. 4-71764 of the same applicant, in which (a) is a vertical sectional view,
(B) is a plan view.

FIG. 5 is a particle size distribution of coke in the furnace circumferential direction obtained by the apparatus of FIG.

[Explanation of symbols]

 1 coke packed bed 2, 2'upper and lower tuyeres 3 raceway 4 gas flow 5 6 coke 7 coke supply hopper 8 charging pipe 12 donut-shaped region including raceway 13 shaft part

Claims (1)

[Claims] 1. A coke packed bed formed by supplying coke from a hopper above a furnace through a plurality of charging pipes,
Out of a plurality of blast tuyeres arranged in the upper and lower two stages in the circumferential direction of the lower part of the furnace, a powdered metal oxide from the upper tuyere and a slag-forming agent for adjusting the slag component, and oxygen from the lower tuyere In a vertical smelting furnace of a coke packed bed system in which a gas is blown to melt and reduce the metal oxide, the coke charging pipe is placed just before the blast tuyere whose central axis is adjacent in the furnace circumferential direction. A coke packed bed type vertical smelting furnace which is provided at an intermediate position between raceways to be formed.