WO2020111666A1

WO2020111666A1 - Fluidized bed furnace

Info

Publication number: WO2020111666A1
Application number: PCT/KR2019/016101
Authority: WO
Inventors: 고창국; 신명균
Original assignee: 주식회사 포스코
Priority date: 2018-11-26
Filing date: 2019-11-22
Publication date: 2020-06-04
Also published as: EP3889532A4; KR102090550B1; EP3889532B1; CN113167534A; EP3889532A1; CN113167534B

Abstract

A fluidized bed furnace comprises: a lower reactor which forms a first fluidized bed space having a first diameter, and which includes a discharge port through which reduced iron fines are discharged; an upper reactor which forms a second fluidized bed space having a second diameter greater than the first diameter, and which includes a charging port through which iron ore fines are charged; and a tapered part which forms a connecting space that allows communication between the first fluidized bed space and the second fluidized bed space, and which directly connects the lower reactor and the upper reactor.

Description

Flow path

The present description relates to a flow path.

In general, in the case of a molten-reduction steelmaking facility in which molten iron ore is directly manufactured using molten iron ore, it includes a plurality of flow paths for flow-reducing the fine iron ore.

The flow furnace reduces the powdered fine iron ore to finely reduced iron by using a high-temperature reducing gas supplied from a molten gas furnace.

Conventional flow furnaces use finely divided iron ore having a particle size of 8 mm or less, but recently, use of extremely fine iron ore having a smaller particle size is required.

However, when a large amount of fine iron ore is charged in a conventional flow path, a stagnant layer is formed inside the flow path by interaction between the fine fine iron ores, or the ultra fine reduced iron reduced from the fine fine iron ore is fused to the inner wall of the flow path. And aggregation to form large particles.

In addition, the conventional flow path should be recovered and re-injected by the cyclone inside the flow path, the ultrafine iron ore having an end velocity smaller than the operating flow rate scattered inside the flow path. As the particle size decreases, the scattering loss increases.

One embodiment is to provide a flow path that minimizes scattering problems while minimizing scattering loss, even when extremely fine iron ore is charged.

In addition, it is intended to provide a flow path capable of using extremely fine iron ore as a raw material at 100%.

One side forms a first fluidized bed space having a first diameter, a lower reactor including an outlet through which finely reduced iron is discharged, a second fluidized bed space having a second larger diameter than the first diameter, and fine iron ore An upper reactor including a charging port to be charged, and a flow path including a taper portion forming a connection space communicating between the first fluidized bed space and the second fluidized bed space, and directly connecting the lower reactor and the upper reactor. Provides

The second diameter may be 3 to 4 times the first diameter.

The outer wall of the tapered portion may have an angle of 45 degrees to 75 degrees with the second radial direction.

The charging port may be higher than 1/2 of the height of the outer wall of the upper reactor.

The outlet is lower than 1/2 of the height of the outer wall of the lower reactor, and may be extended upward.

A porous plate positioned between the second fluidized bed space and the connection space and including a plurality of through holes may be further included.

The first fluidized bed space may extend from the second fluidized bed space to the first fluidized bed space, and may further include a stand pipe supported on the porous plate.

A plurality of nitrogen purge supply pipes disposed along the circumferential direction of the outer wall of the upper reactor may be further included.

The lower reactor may further include a dispersion plate through which a reducing gas supplied to the first fluidized bed space passes.

According to one embodiment, even when extremely fine iron ore is charged, a flow path is provided that minimizes scattering losses and minimizes fusion problems.

In addition, there is provided a flow path capable of using extremely fine iron ore at 100% as a raw material.

1 is a perspective view showing a flow path according to a first embodiment.

2 is a view showing the nitrogen purge supply pipe shown in FIG.

3 is a view showing the interior of the flow path according to the first embodiment.

4 is a perspective view showing a flow path according to a second embodiment.

5 is a view showing the interior of the flow path according to the second embodiment.

6 is a perspective view showing a flow path according to a third embodiment.

7 is a view showing the interior of the flow path according to the third embodiment.

Hereinafter, exemplary embodiments of the present invention will be described in detail with reference to the accompanying drawings so that those skilled in the art to which the present invention pertains can easily practice. The present invention can be implemented in many different forms and is not limited to the embodiments described herein.

In order to clearly describe the present invention, parts irrelevant to the description are omitted, and the same reference numerals are assigned to the same or similar elements throughout the specification.

Also, in the specification, when a part “includes” a certain component, this means that other components may be further included instead of excluding other components, unless otherwise stated.

Hereinafter, a flow path according to the first embodiment will be described with reference to FIGS. 1 to 3. The flow path may be a flow path included in the molten reduction steel plant, but is not limited thereto.

For example, the molten reduction steel plant may include at least one flow path for reducing the fine iron ore to finely reduced iron, a compacting device for compressing finely reduced iron into a compact, and a molten gas furnace, but is not limited thereto. It may further include a variety of configurations. The fine iron ore is charged into the flow furnaces, and the finely reduced iron reduced from the flow furnaces is made of a compact in a compacting apparatus and supplied to a molten gas furnace together with coal briquettes to be made of molten iron. In addition, the reducing gas generated from the molten gas furnace can be supplied to the flow furnaces.

1 is a perspective view showing a flow path according to a first embodiment.

Referring to FIG. 1, the flow path 1000 according to the first embodiment includes a lower reactor 100, an upper reactor 200, a tapered portion 300, and a plurality of nitrogen purge supply pipes 400.

The lower reactor 100 has a cylindrical shape, and forms a first fluidized bed space FS1 having a first diameter D1 in plan view.

In the first fluidized bed space FS1 of the lower reactor 100, a high-speed fluidized bed (Turbulent Fluidized Bed to Fast Fluidized Bed) is formed, and vigorous gas solid mixing may occur.

The lower reactor 100 includes an outlet 110 through which finely reduced iron is discharged.

In the first fluidized bed space FS1 of the lower reactor 100, the finely reduced iron reduced from the finely divided iron ore is discharged through the outlet 110.

The outlet 110 is positioned lower than 1/2 of the height of the outer wall 101 of the lower reactor 100 and extends upward.

The lower reactor 100 includes a dispersion plate 120 through which the reducing gas RG supplied to the first fluidized bed space FS1 passes.

The dispersion plate 120 includes a plurality of through holes through which the reducing gas RG passes. The reducing gas RG is supplied from the lower portion of the dispersion plate 120, and the reducing gas RG passes through the first fluidized bed space FS1 of the lower reactor 100 and the second fluidized bed space FS2 of the upper reactor 200. ) And discharged to the upper portion of the upper reactor 200. The reducing gas RG may be generated from the molten gas furnace of the molten reducing steel plant, and the reducing gas RG discharged to the upper portion of the upper reactor 200 may be supplied to the lower portion of another flow path.

The upper reactor 200 has a cylindrical shape having a larger volume than the lower reactor 100. The upper reactor 200 planarly forms a second fluidized bed space FS2 having a second diameter D2 that is larger than the first diameter D1.

The second diameter D2 may be 3 to 4 times the first diameter D1.

In the second fluidized bed space FS2 of the upper reactor 200, a fluidized bed (Minimum fluidized bed to Bubbling fluidized bed) is formed due to a low gas flow rate compared to the gas flow rate of the first fluidized bed space FS1.

The upper reactor 200 includes a charging port 210 into which fine iron ore is charged.

In the second fluidized bed space FS2 of the upper reactor 200, fine iron ore is charged through the charging port 210.

The charging port 210 is positioned higher than 1/2 of the height of the outer wall 201 of the upper reactor 200 and extends upward.

The tapered portion 300 directly connects between the lower reactor 100 and the upper reactor 200. The tapered portion 300 forms a connection space CS communicating between the first fluidized bed space FS1 and the second fluidized bed space FS2.

The outer wall 301 of the tapered portion 300 may have a second diameter D2 direction and an angle of 45 degrees to 75 degrees.

The tapered portion 300, the lower reactor 100, and the upper reactor 200 may be integrally formed, but are not limited thereto.

The plurality of nitrogen purge supply pipes 400 are disposed along the circumferential direction of the outer wall 201 of the upper reactor 200.

2 is a view showing the nitrogen purge supply pipe shown in FIG. 2A is a view showing an example of a nitrogen purge supply pipe 400 connected to the upper reactor 200.

Referring to (A) of FIG. 2, the nitrogen purge supply pipe 400 is located at a lower portion of the outer wall 201 of the upper reactor 200 and is adjacent to the outer wall 301 of the tapered portion 300.

The nitrogen purge supply pipe 400 may extend in the same direction as the extending direction of the outer wall 301 of the tapered portion 300 to facilitate the flow of charges from the upper reactor 200 toward the tapered portion 300. .

2B is a view showing an example of the arrangement of a plurality of nitrogen purge supply pipes 400 connected to the upper reactor 200.

Referring to FIG. 2B, each of the plurality of nitrogen purge supply pipes 400 has an angle of 45 degrees to the center of the second fluidized bed space FS2 along the circumference of the outer wall 201 of the upper reactor 200. Can be arranged.

FIG. 2C is a view showing another example of the arrangement of the plurality of nitrogen purge supply pipes 400 connected to the upper reactor 200.

2(C), each of the plurality of nitrogen purge supply pipes 400 has an angle of 30 degrees with the center of the second fluidized bed space FS2 along the circumference of the outer wall 201 of the upper reactor 200 Can be arranged.

3 is a view showing the interior of the flow path according to the first embodiment. In FIG. 3, the solid flow may mean the flow of the fine iron ore and the flow of finely reduced iron, and the solid existence region may mean the region of the fine iron ore and finely reduced iron.

Referring to FIG. 3, when the fine iron ore (IO1) is charged into the charging port 210 of the upper reactor 200 of the flow path 1000 through which the reducing gas RG is injected through the dispersion plate 120, the second In the fluidized bed space FS2, a smooth fluidized bed FB1 is formed due to a low gas flow rate.

The remaining fluidized bed FB1 formed in the second fluidized bed space FS2 of the upper reactor 200 passes through the connection space CS of the tapered portion 300 and the first fluidized bed space FS1 of the lower reactor 100 which is a high-speed region. Will move to

In the first fluidized bed space FS1 of the lower reactor 100, a high-speed fluidized bed FB2 is formed to generate vigorous gas solid mixing. Due to this, it is minimized that the fusion phenomenon in which the finely reduced iron (IO2) reduced in the high-speed fluidized bed (FB2) aggregates with each other is generated.

The finely reduced iron (IO2) reduced in the lower reactor 100 is discharged by a pressure difference to the outside of the lower reactor 100 through the outlet 110.

In the narrow first fluidized bed space FS1 of the lower reactor 100, the finely charged iron ore IO1 is reduced under turbulent fluidized bed conditions as a high-speed fluidized bed FB2.

Since the reducing gas (RG) and the fine iron ore (IO1) are violently mixed by the rapid gas flow in the first fluidized bed space (FS1) of the lower reactor 100, the reduced iron (IO2) reduced from the inner wall of the lower reactor 100 ) Or fusion between the reduced particles to form large particles is suppressed (agglomeration).

Reduction occurs rapidly due to a high gas/ore ratio in the first fluidized bed space FS1 of the lower reactor 100. The finely reduced iron (IO2) reduced in the first fluidized bed space FS1 is discharged through the outlet 110 by a pressure difference.

The finely reduced iron (IO2) reduced by vigorous mixing in the first fluidized bed space (FS1) of the lower reactor (100) together with the reducing gas (RG) moving to the upper reactor (200), the second fluidized bed of the upper reactor (200) Although it may be scattered into the space FS2, the gas flow rate is reduced by the second fluidized bed space FS2 of the upper reactor 200 that is rapidly widened compared to the first fluidized bed space FS1 of the lower reactor 100. The finely reduced iron (IO2) scattered into the fluidized bed space (FS2) is directly dropped into the first fluidized bed space (FS1) of the lower reactor 100 by gravity.

In the second fluidized-bed space FS2 of the upper reactor 200, the temperature is lower than the first fluidized-bed space FS1 of the lower reactor 100 by heat exchange with the fine iron ore IO1 at room temperature charged from the charging port 210. And a gas/ore ratio, resulting in a low reduction reaction.

Therefore, in the second fluidized bed space FS2 of the upper reactor 200, the problem of fusion of the finely reduced iron (IO2) does not occur in the bubble fluidized bed atmosphere, which is the calm fluidized bed FB1, and the first fluidized bed space of the lower reactor 100 ( In FS1), the reduction of the finely reduced iron (IO2) is accelerated to the turbulent fluidized bed atmosphere, which is a high-speed fluidized bed (FB2), and is discharged through the outlet 110 to minimize the fusion problem of the finely reduced iron (IO2).

That is, by including the upper reactor 200, the lower reactor 100, and the tapered portion 300, even if the ultrafine iron ore is charged, a flow path 1000 is provided that minimizes scattering losses and minimizes fusion problems.

In addition, by including the upper reactor 200, the lower reactor 100, and the tapered portion 300, a flow path 1000 capable of using extremely fine iron ore at 100% as a raw material is provided.

Hereinafter, the flow path according to the second embodiment will be described with reference to FIGS. 4 and 5. Hereinafter, different parts from the flow path according to the first embodiment will be described.

4 is a perspective view showing a flow path according to a second embodiment.

Referring to FIG. 4, the flow path 1002 according to the second embodiment includes a lower reactor 100, an upper reactor 200, a tapered portion 300, a plurality of nitrogen purge supply pipes 400, and a perforated plate 500 ).

The perforated plate 500 is positioned between the second fluidized bed space FS2 of the upper reactor 200 and the connection space CS of the tapered portion 300 and includes a plurality of through holes.

The perforated plate 500 is positioned between the second fluidized bed space FS2 and the connection space CS, and serves as a partition wall between the second fluidized bed space FS2 and the first fluidized bed space FS1.

The perforated plate 500 may physically separate between the upper reactor 200 and the lower reactor 100.

Referring to FIG. 5, when the fine iron ore (IO1) is charged into the charging port 210 of the upper reactor 200 of the flow path 1002 through which the reducing gas RG is injected through the dispersion plate 120, the second In the fluidized bed space FS2, a smooth fluidized bed FB1 is formed due to a low gas flow rate. The fine iron ore (IO1) is partially reduced in the calm fluidized bed (FB1) by the porous plate 500.

Thereafter, when the partially reduced fine iron (IO2) and fine iron ore (IO1) partially reduced in the second fluidized bed space FS2 pass through the through holes of the perforated plate 500 and move to the lower reactor 100, the lower part is due to the rapid flow rate. In the first fluidized bed space FS1 of the reactor 100, a high-speed fluidized bed FB2 is formed to generate vigorous gas solid mixing. Due to this, it is minimized that the fusion phenomenon in which the finely reduced iron (IO2) reduced in the high-speed fluidized bed (FB2) aggregates with each other is generated.

In other words, by including the upper reactor 200, the lower reactor 100, the tapered portion 300, the perforated plate 500, even if a very fine iron ore is charged, the flow path that minimizes scattering losses and minimizes fusion problems ( 1002) is provided.

In addition, by including the upper reactor 200, the lower reactor 100, the tapered portion 300, the perforated plate 500, a flow path 1002 is provided that can use extremely fine iron ore as 100% as a raw material.

Hereinafter, the flow path according to the third embodiment will be described with reference to FIGS. 6 and 7. Hereinafter, different parts from the flow path according to the first embodiment will be described.

6 is a perspective view showing a flow path according to a third embodiment.

Referring to FIG. 6, the flow path 1003 according to the third embodiment includes a lower reactor 100, an upper reactor 200, a tapered portion 300, a plurality of nitrogen purge supply pipes 400, and a perforated plate 500 ), and includes a stand pipe 600.

The stand pipe 600 extends from the second fluidized bed space FS2 to the first fluidized bed space FS1 through the perforated plate 500. The stand pipe 600 is supported by the perforated plate 500 corresponding to the first fluidized bed space FS1 of the lower reactor 100.

The stand pipe 600 facilitates the flow of fine iron ore from the upper reactor 200 to the lower reactor 100.

Referring to FIG. 7, when the fine iron ore (IO1) is charged into the charging port 210 of the upper reactor 200 of the flow path 1003 through which the reducing gas RG is injected through the dispersion plate 120, the second In the fluidized bed space FS2, a smooth fluidized bed FB1 is formed due to a low gas flow rate. The fine iron ore IO1 is partially reduced by the porous plate 500 in the calm fluidized bed FB1.

At this time, the lower reactor of the high pressure through the stand pipe 600 from the second fluidized bed space (FS2) of the upper reactor 200 of the lower pressure part of the fine iron ore (IO1) located in the second fluidized bed space (FS2) ( 100) is smoothly moved to the first fluidized bed space FS1.

Thereafter, the partially reduced fine iron (IO2) and fine iron ore (IO1) partially reduced in the second fluidized bed space FS2 pass through the through holes of the perforated plate 500 and move to the lower reactor 100, and the stand pipe 600 When the pulverized iron ore (IO1) moves to the lower reactor 100 through, a high-speed fluidized bed (FB2) is formed in the first fluidized bed space (FS1) of the lower reactor 100 due to the fast flow rate, resulting in intense gas solid mixing. . Due to this, it is minimized that the fusion phenomenon in which the finely reduced iron (IO2) reduced in the high-speed fluidized bed (FB2) aggregates with each other is generated.

That is, by including the upper reactor 200, the lower reactor 100, the tapered portion 300, the perforated plate 500, and the stand pipe 600, even when extremely fine iron ore is charged, scattering losses are minimized and welding problems are minimized. A flow path 1003 in which is minimized is provided.

In addition, by including the upper reactor 200, the lower reactor 100, the tapered portion 300, the perforated plate 500, the stand pipe 600, a flow path capable of using extremely fine iron ore at 100% as a raw material ( 1003) is provided.

Although the embodiments of the present invention have been described in detail above, the scope of rights of the present invention is not limited thereto, and various modifications and improvements of those skilled in the art using the basic concept of the present invention defined in the following claims are also provided. It belongs to the scope of rights.

-Description of code-

First fluidized bed space (FS1), lower reactor 100, second fluidized bed space (FS2), upper reactor 200, connection space (CS), tapered portion 300

Claims

A lower reactor forming a first fluidized bed space having a first diameter and including an outlet through which the finely reduced iron is discharged;

An upper reactor forming a second fluidized bed space having a second diameter larger than the first diameter, and including a charging port into which fine iron ore is charged; And

A tapered portion forming a connection space communicating between the first fluidized bed space and the second fluidized bed space, and directly connecting between the lower reactor and the upper reactor

It includes,

A flow path in which a high speed fluidized bed is formed in the first fluidized bed space, and a calm fluidized bed having a lower flow rate than the high speed fluidized bed is formed in the second fluidized bed space.
In claim 1,

The second diameter is 3 to 4 times the flow path of the first diameter.
In claim 1,

The outer wall of the tapered portion has a flow path having an angle of 45 to 75 degrees with the second radial direction.
In claim 1,

The inlet is a flow path higher than 1/2 of the height of the outer wall of the upper reactor.
In claim 1,

The outlet is lower than 1/2 of the height of the outer wall of the lower reactor, the flow path extending upward.
In claim 1,

A flow path positioned between the second fluidized bed space and the connection space, and further comprising a porous plate including a plurality of through holes.
In claim 6,

A flow path extending from the second fluidized bed space to the first fluidized bed space through the perforated plate and further comprising a stand pipe supported on the perforated plate.
In claim 1,

A flow path further comprising a plurality of nitrogen purge supply pipes arranged along the circumferential direction of the outer wall of the upper reactor.
In claim 1,

The lower reactor further includes a dispersion plate through which a reducing gas supplied to the first fluidized bed space passes.