CN113167534A

CN113167534A - Fluidized bed furnace

Info

Publication number: CN113167534A
Application number: CN201980077736.XA
Authority: CN
Inventors: 高彰国; 申明均
Original assignee: Posco Co Ltd
Current assignee: Posco Holdings Inc
Priority date: 2018-11-26
Filing date: 2019-11-22
Publication date: 2021-07-23
Anticipated expiration: 2039-11-22
Also published as: EP3889532A4; EP3889532A1; KR102090550B1; WO2020111666A1; CN113167534B; EP3889532B1

Abstract

The fluidized bed furnace includes: a lower reactor forming a first fluidized bed space having a first diameter, including a discharge port through which reduced iron fine powder is discharged; an upper reactor forming a second fluidized bed space having a second diameter larger than the first diameter, including a charging port into which iron ore fines are charged; and a tapered portion forming a connecting space communicating between the first fluidized bed space and the second fluidized bed space, directly connecting the lower reactor and the upper reactor.

Description

Fluidized bed furnace

Technical Field

This description relates to fluidized bed furnaces.

Background

Generally, in the case of a smelting reduction steelmaking apparatus for manufacturing molten irons directly using iron ore fine powders, a plurality of fluidized bed furnaces for performing a fluidized reduction process on the iron ore fine powders are included.

The fluidized bed furnace reduces the fine powder of powdered iron ore to fine reduced iron powder by using a high-temperature reducing gas supplied from the melter-gasifier.

The conventional fluidized bed furnace substantially uses iron ore fine powder having a particle size of 8mm or less, but recently, it is required to use iron ore fine powder having a smaller particle size.

However, when a large amount of iron ore micropowder is charged into a conventional fluidized bed furnace, there is a problem that a retention layer is formed inside the fluidized bed furnace or reduced iron micropowder reduced from the iron ore micropowder is fused and aggregated on the inner wall of the fluidized bed furnace to form large particles due to interaction between the iron ore micropowder.

In addition, in the conventional fluidized bed furnace, the iron ore micropowder having a final velocity lower than the operating flow velocity, which is scattered inside the fluidized bed furnace, is recovered and re-injected by means of the cyclone inside the fluidized bed furnace, but the cyclone efficiency is reduced as the particle size of the iron ore micropowder, which is scattered particles, is reduced, and thus there is a problem in that scattering loss is increased.

Disclosure of Invention

Technical problem to be solved

An embodiment is directed to providing a fluidized bed furnace that minimizes a clinkering problem while minimizing a scattering loss even though iron ore ultra-fine powder is charged.

In addition, it is intended to provide a fluidized bed furnace capable of 100% using iron ore micropowder as a raw material.

Means for solving the problems

In one aspect, there is provided a fluidized bed furnace comprising: a lower reactor forming a first fluidized bed space having a first diameter, including a discharge port through which reduced iron fine powder is discharged; an upper reactor forming a second fluidized bed space having a second diameter larger than the first diameter, including a charging port into which iron ore fines are charged; and a tapered portion forming a connecting space communicating between the first fluidized bed space and the second fluidized bed space, directly connecting the lower reactor and the upper reactor.

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 diameter direction.

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

The discharge outlet may extend upwardly below the level 1/2 of the outer wall of the lower reactor.

A perforated plate comprising a plurality of through-holes may be further included, the perforated plate being located between the second fluidized bed space and the connecting space.

It may further comprise a riser pipe extending from the second fluidized bed space, through the perforated plate, to the first fluidized bed space, supported by the perforated plate.

A plurality of nitrogen purge supply pipes arranged in a circumferential direction of an outer wall of the upper reactor may be further included.

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

Effects of the invention

According to one embodiment, there is provided a fluidized bed furnace that minimizes the problem of accretion while minimizing the scattering loss even if iron ore ultra-fine powder is charged.

Further, a fluidized bed furnace capable of 100% using the iron ore micropowder as a raw material is provided.

Drawings

Fig. 1 is a perspective view showing a fluidized bed furnace of the first embodiment.

FIG. 2 is a view showing the nitrogen purge supply pipe shown in FIG. 1.

Fig. 3 is a view showing the inside of the fluidized bed furnace of the first embodiment.

Fig. 4 is a perspective view showing a fluidized bed furnace of the second embodiment.

Fig. 5 is a view showing the interior of the fluidized bed furnace of the second embodiment.

Fig. 6 is a perspective view showing a fluidized bed furnace of the third embodiment.

Fig. 7 is a view showing the interior of the fluidized bed furnace of the third embodiment.

Detailed Description

Embodiments of the present invention will be described in detail below with reference to the accompanying drawings so that those skilled in the art can easily implement the present invention. The present invention may be embodied in many different forms and is not limited to the embodiments described herein.

In order to clearly explain the present invention, portions that are not relevant to the description are omitted, and the same reference numerals are given to the same or similar constituent elements throughout the specification.

In the following description, when a part "includes" a certain component, other components are not excluded unless specifically stated to the contrary, but it means that other components may be included.

Referring now to fig. 1 to 3, a fluidized bed furnace of a first embodiment will be described. The fluidized bed furnace may be, but is not limited to, a fluidized bed furnace included in a smelting reduction steelmaking apparatus.

As one example, the smelting reduction steelmaking apparatus may include at least one fluidized bed furnace that reduces iron ore fines into reduced iron fines, a compacting device that compacts the reduced iron fines to prepare compacts, a melter-gasifier, but is not limited thereto, and may further include various well-known configurations. Iron ore fine powder is charged into a fluidized bed furnace, and reduced iron fine powder reduced from the fluidized bed furnace is prepared into a compact in a compacting apparatus, and supplied to a melter-gasifier together with formed char to be manufactured into molten iron. In addition, the reducing gas generated from the melter-gasifier may be supplied to the fluidized-bed furnace.

Referring to fig. 1, the fluidized bed furnace 1000 of 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 form forming a first fluidized bed space FS1 having a first diameter D1 in plan.

In the first fluidized bed space FS1 of the lower reactor 100, a high velocity fluidized bed (turbulent fluidized bed as well as fast fluidized bed) is formed, and vigorous gas-solid mixing can occur.

The lower reactor 100 includes a discharge port 110 through which fine reduced iron powder is discharged.

In the first fluidized bed space FS1 of the lower reactor 100, the reduced iron fine powder reduced from the iron ore fine powder is discharged through the discharge port 110.

The discharge port 110 is disposed at a level lower than 1/2 of the outer wall 101 of the lower reactor 100 and extends upward.

The lower reactor 100 includes a dispersion plate 120, and the dispersion plate 120 passes the reducing gas RG supplied to the first fluidized bed space FS 1.

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 is discharged to the upper portion of the upper reactor 200 through the first fluidized bed space FS1 of the lower reactor 100, the second fluidized bed space FS2 of the upper reactor 200. The reducing gas RG may be generated from a melter-gasifier of a smelting reduction steelmaking facility, and the reducing gas RG discharged to the upper portion of the upper reactor 200 may be supplied to the lower portion of another fluidized bed furnace.

The upper reactor 200 has a cylindrical form having a larger volume than the lower reactor 100. The upper reactor 200 forms a second fluidized bed space FS2 having a second diameter D2 which is larger in plan 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 quiet fluidized bed (minimum fluidized bed and bubbling fluidized bed) is formed because the gas flow rate is lower than that of the first fluidized bed space FS 1.

The upper reactor 200 includes a charging port 210 into which iron ore fines are charged.

Iron ore fines are charged into the second fluidized bed space FS2 of the upper reactor 200 through the charging inlet 210.

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

The tapered portion 300 directly connects the lower reactor 100 and the upper reactor 200. The cone 300 forms a connecting space CS communicating between the first fluidized bed space FS1 and the second fluidized bed space FS 2.

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

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

A plurality of nitrogen purge supply pipes 400 may be disposed along a circumferential direction of the outer wall 201 of the upper reactor 200.

FIG. 2 is a view showing the nitrogen purge supply pipe shown in FIG. 1. Fig. 2 (a) is a view showing an example of a nitrogen purge supply pipe 400 connected to the upper reactor 200.

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

The nitrogen purge supply pipe 400 may extend in the same direction as the extension direction of the outer wall 301 of the tapered part 300 so that the contents smoothly flow from the upper reactor 200 to the tapered part 300.

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

Referring to fig. 2 (B), a plurality of nitrogen purge supply pipes 400 may be respectively disposed along the circumference of the outer wall 201 of the upper reactor 200 at an angle of 45 degrees to the center of the second fluidized bed space FS 2.

Fig. 2 (C) is a view showing another example of the configuration of the plurality of nitrogen purge supply pipes 400 connected to the upper reactor 200.

Referring to (C) of fig. 2, a plurality of nitrogen purge supply pipes 400 may be respectively disposed along the circumference of the outer wall 201 of the upper reactor 200 at an angle of 30 degrees from the center of the second fluidized bed space FS 2.

Fig. 3 is a view showing the inside of the fluidized bed furnace of the first embodiment. In fig. 3, the solid flow may mean a flow of iron ore fines and a flow of reduced iron fines, and the solid existence region may mean an existence region of iron ore fines and reduced iron fines.

Referring to fig. 3, if the iron ore fines IO1 are charged at the charge port 210 of the upper reactor 200 of the fluidized bed furnace 1000 into which the reducing gas RG is injected through the dispersion plate 120, a flat fluidized bed FB1 is formed due to a low gas flow rate in the second fluidized bed space FS 2.

The calm fluidized bed FB1 formed in the second fluidized bed space FS2 of the upper reactor 200 moves to the first fluidized bed space FS1 of the lower reactor 100 as a high-speed region through the connecting space CS of the conical portion 300.

In the first fluidized bed space FS1 of the lower reactor 100, a high velocity fluidized bed FB2 is formed, and vigorous gas-solid mixing occurs. Therefore, in the high-velocity fluidized bed FB2, the occurrence of the phenomenon of the reduced iron fine powder IO2 fusing together is minimized.

The reduced iron fine powder IO2 reduced in the lower reactor 100 is discharged outside the lower reactor 100 through the discharge port 110 by means of a pressure difference.

In the narrow first fluidized bed space FS1 of the lower reactor 100, iron ore fines IO1 as charge are reduced under turbulent fluidized bed conditions as a high velocity fluidized bed FB 2.

In the first fluidized bed space FS1 of the lower reactor 100, the reducing gas RG is vigorously mixed with the iron ore fine powder IO1 due to the rapid gas flow, thereby suppressing the formation of large particles (agglomeration) due to the fusion of the reduced iron fine powder IO2 to the inner wall of the lower reactor 100 or between the reduced particles.

In the first fluidized bed space FS1 of the lower reactor 100, the reduction takes place rapidly due to the high gas/ore ratio. The reduced iron fine powder IO2 reduced in the first fluidized bed space FS1 is discharged through the discharge port 110 by means of a pressure difference.

In the first fluidized bed space FS1 of the lower reactor 100, the reduced iron fine powder IO2 reduced by intensive mixing is scattered to the second fluidized bed space FS2 of the upper reactor 200 together with the reducing gas RG moving to the upper reactor 200, but the gas flow rate is reduced by the second fluidized bed space FS2 of the upper reactor 200 which is sharply widened from the first fluidized bed space FS1 of the lower reactor 100, and thus the reduced iron fine powder IO2 scattered to the second fluidized bed space FS2 directly falls to 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 and the gas/ore ratio are lower than those of the first fluidized bed space FS1 of the lower reactor 100 by heat exchange with the normal temperature iron ore fine powder IO1 charged from the charge port 210, and thus a low reduction reaction occurs.

Therefore, in the second fluidized bed space FS2 of the upper reactor 200, the problem of the melt-sticking of the reduced iron fine powder IO2 does not occur due to the bubbling fluidized bed atmosphere as the flat fluidized bed FB1, and in the first fluidized bed space FS1 of the lower reactor 100, the reduction of the reduced iron fine powder IO2 is accelerated due to the turbulent fluidized bed atmosphere as the high-speed fluidized bed FB2, and is discharged through the discharge port 110, and the problem of the melt-sticking of the reduced iron fine powder IO2 is minimized.

That is, the fluidized bed furnace 1000 including the upper reactor 200, the lower reactor 100, and the tapered portion 300 is provided to minimize the problem of accretion while minimizing the scattering loss even if the iron ore micropowder is charged.

In addition, the upper reactor 200, the lower reactor 100, and the tapered portion 300 are included, thereby providing a fluidized bed furnace 1000 capable of 100% using an iron ore ultra-fine powder as a raw material.

Next, a fluidized bed furnace according to a second embodiment will be described with reference to fig. 4 and 5. The following description is made of a portion different from the fluidized bed furnace of the first embodiment described above.

Referring to fig. 4, the fluidized bed furnace 1002 of 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 located between the second fluidized bed space FS2 of the upper reactor 200 and the connection space CS of the conical part 300, and includes a plurality of penetration holes.

The perforated plate 500 is located between the second fluidized bed space FS2 and the connection space CS, acting as a partition wall between the second fluidized bed space FS2 and the first fluidized bed space FS 1.

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

Referring to fig. 5, if the iron ore fines IO1 are charged at the charge port 210 of the upper reactor 200 of the fluidized bed furnace 1002 into which the reducing gas RG is injected through the dispersion plate 120, a calm fluidized bed FB1 is formed in the second fluidized bed space FS2 due to the low gas flow rate. Iron ore fines IO1 are partially reduced in a stationary fluidized bed FB1 by means of a perforated plate 500.

Then, after the reduced iron fine powder IO2 and the iron ore fine powder IO1, which are partially reduced in the second fluidized bed space FS2, move to the lower reactor 100 through the penetration holes of the perforated plate 500, 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, and intensive gas-solid mixing occurs. Therefore, in the high-velocity fluidized bed FB2, the occurrence of the phenomenon of the melt-sticking phenomenon due to the mutual aggregation of the reduced iron fine powder IO2 is minimized.

That is, the fluidized bed furnace 1002 includes the upper reactor 200, the lower reactor 100, the tapered portion 300, and the porous plate 500, thereby providing a fluidized bed furnace 1002 that minimizes a melting and sticking problem while minimizing a scattering loss even if iron ore micropowder is charged.

Further, the upper reactor 200, the lower reactor 100, the tapered portion 300, and the porous plate 500 are included, thereby providing a fluidized bed furnace 1002 capable of 100% using an iron ore ultra-fine powder as a raw material.

Next, a fluidized bed furnace according to a third embodiment will be described with reference to fig. 6 and 7. The following description is made of a portion different from the fluidized bed furnace of the first embodiment described above.

Referring to fig. 6, the fluidized bed furnace 1003 of the third embodiment includes a lower reactor 100, an upper reactor 200, a tapered portion 300, a plurality of nitrogen purge supply pipes 400, a perforated plate 500, and a riser 600.

The riser 600 extends from the second fluidized bed space FS2 through the perforated plate 500 to the first fluidized bed space FS 1. The riser 600 corresponds to the first fluidized bed space FS1 of the lower reactor 100 and is supported by a perforated plate 500.

The riser 600 smoothes the flow of iron ore fines from the upper reactor 200 to the lower reactor 100.

Referring to fig. 7, if the iron ore fines IO1 are charged at the charge port 210 of the upper reactor 200 of the fluidized bed furnace 1003 into which the reducing gas RG is injected through the dispersion plate 120, a flat fluidized bed FB1 is formed in the second fluidized bed space FS2 due to the low gas flow rate. Iron ore fines IO1 are partially reduced in a stationary fluidized bed FB1 by means of a perforated plate 500.

At this time, a part of the iron ore fines IO1 located in the second fluidized bed space FS2 smoothly moves from the second fluidized bed space FS2 of the lower pressure upper reactor 200 to the first fluidized bed space FS1 of the higher pressure lower reactor 100 through the riser 600.

Then, after the reduced iron fines IO2 and the iron ore fines IO1, which are partially reduced in the second fluidized bed space FS2, pass through the penetration holes of the perforated plate 500 and move to the lower reactor 100, and the iron ore fines IO1 move to the lower reactor 100 through the standpipe 600, 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, and intensive gas-solid mixing occurs. Therefore, in the high-velocity fluidized bed FB2, the occurrence of the phenomenon of the melt-sticking caused by the mutual aggregation of the reduced iron fine powder IO2 is minimized.

That is, the fluidized bed furnace 1003 includes an upper reactor 200, a lower reactor 100, a tapered portion 300, a perforated plate 500, and a riser 600, thereby providing a fluidized bed furnace 1003 that minimizes a scattering loss and a clinkering problem even if iron ore micropowder is charged.

In addition, the upper reactor 200, the lower reactor 100, the tapered part 300, the perforated plate 500, and the stand pipe 600 are included, thereby providing a fluidized bed furnace 1003 capable of 100% using iron ore micropowder as a raw material.

The embodiments of the present invention have been described in detail, but the scope of the claims of the present invention is not limited thereto, and those skilled in the art will appreciate that various modifications and improvements of the basic concept of the present invention defined by the appended claims are also within the scope of the claims of the present invention.

Reference numerals

First fluidized bed space: FS1, lower reactor: 100, second fluidized bed space: FS2, upper reactor: 200, connection space: CS, taper: 300.

Claims

1. a fluidized bed furnace, comprising:

a lower reactor forming a first fluidized bed space having a first diameter, including a discharge port through which reduced iron fine powder is discharged;

an upper reactor forming a second fluidized bed space having a second diameter larger than the first diameter, including a charging port into which iron ore fines are charged; and

a conical portion forming a connecting space communicating between the first fluidized bed space and the second fluidized bed space, directly connecting the lower reactor with the upper reactor;

a high-velocity fluidized bed is formed in the first fluidized bed space, and a quiet fluidized bed having a lower flow rate than the high-velocity fluidized bed is formed in the second fluidized bed space.

2. The fluidized bed furnace of claim 1,

the second diameter is 3 to 4 times the first diameter.

3. The fluidized bed furnace of claim 1,

the outer wall of the tapered portion has an angle of 45 degrees to 75 degrees with the second diameter direction.

4. The fluidized bed furnace of claim 1,

the loading port is higher than 1/2 of the height of the outer wall of the upper reactor.

5. The fluidized bed furnace of claim 1,

the discharge port is lower than 1/2 in the height of the outer wall of the lower reactor and extends upward.

6. The fluidized bed furnace of claim 1,

still include the perforated plate, the perforated plate is located the second fluidized bed space with between the linkage space, including a plurality of perforating holes.

7. The fluidized bed furnace of claim 6,

further comprising a riser extending from the second fluidized bed space, through the perforated plate, to the first fluidized bed space, supported on the perforated plate.

8. The fluidized bed furnace of claim 1,

and a plurality of nitrogen purge supply pipes arranged in a circumferential direction of an outer wall of the upper reactor.

9. The fluidized bed furnace of claim 1,

the lower reactor further includes a dispersion plate that passes the reducing gas supplied to the first fluidized bed space therethrough.