JP2991201B1 - Reactor - Google Patents

Abstract

An object of the present invention is to eliminate excessive accumulation of fine powder, particularly on the outer ring of a nozzle. A vessel, which is a fluidized bed reactor, includes a plurality of nozzles for introducing a fluidizing gas.
At least some of the nozzles 28 are provided with a plate 32 near the inlet of the nozzle 28 that redirects the flow of fluidizing gas to the nozzles. By providing the plate 32 at the inlet of the nozzle 28, a uniform flow distribution of the fluidizing gas through the nozzle 28 is achieved, the pressure drop through the nozzle 28 is kept relatively high and the fines Good fluidization gas acceleration to remove fouling is ensured.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a reactor used in a fluidized-powder system, and more particularly to a fluidized-bed reactor or a furnace particularly useful for direct reduction of iron ore in a fluidized-bed process. It is about.

[0002]

2. Description of the Related Art Fluidized bed processes
s) is of great importance related to the direct reduction of iron ore. In a typical fluidized bed process for iron ore,
In a vertical vessel (ie, a reactor) having a single reduction stage, or, generally, a series of reduction stages,
Iron ores and iron oxides are reduced stepwise or progressively. In this type of process, the ore to be reduced is fed internally at the top of the vessel and flows downward in countercurrent relation to the rising fluidizing gas flow in the vessel. The fluidizing gas generally consists of a hot reducing gas consisting of carbon monoxide, hydrogen and other known gas mixtures.

[0003]

By the way, the fluidizing gas is sent to a fluidized bed for contact with iron ore through a plurality of nozzles arranged in a vertical wall arranged in a container. However, in fluidized bed processes, especially for the direct reduction of iron ore, significant problems arise due to fouling and plugging or plugging of these nozzles. That is, "fine powder" of metal particles adheres to the inner wall of the nozzle due to fouling and plugging of the nozzle, and the fine powder eventually completely blocks the nozzle.

[0004] US Patent No. 3,910,769 discloses fluidizing in combination with a conical nozzle to provide preferential flow through the nozzle to prevent the deposition of fines on the inner wall surface of the nozzle. It has been proposed to provide a baffle or baffle at the gas inlet. While such a design has proven to be beneficial, problems arise with this design, especially with respect to the outer race of the nozzle. In other words, it has been found that the baffle plate causes the fine powder to preferentially accumulate in the outer ring of the nozzle, more specifically, on the wall of the outer ring of the nozzle. This type of accumulation is due to the flow generated by the baffle plate, which creates a strong lateral flow at the nozzle entrance.

Accordingly, it is a primary object of the present invention to provide a mechanism which can eliminate or eliminate cross flow at the nozzle inlet of the outer ring of the nozzle, thereby eliminating or eliminating excessive accumulation of fines on the outer ring of the nozzle. It is to provide a reactor.

[0006]

According to the present invention, at least the outer ring of a nozzle in a fluidized bed apparatus has a plate or plate near the inlet of the nozzle which redirects or changes the flow of fluidizing gas to the nozzle. A shaped member is provided. By providing the plate at the inlet of the nozzle in this manner, the following is performed. An even flow distribution of the fluidizing gas through the nozzle is achieved. The pressure drop through the nozzle is kept relatively high, which ensures good acceleration of the fluidizing gas to remove fines from adhering to the inner surface of the nozzle. Other objects of the present invention will be apparent from the following description.

[0007]

Embodiments of the present invention will be described below. It should be noted that the following description will be made with particular reference to the single-layer reactor illustrated schematically in FIG. 1, but the invention is theoretically described in US Pat. No. 3,910,769. The present invention can be similarly applied to a multi-layer reactor or a plurality of single-layer reactors.

Referring to FIG. 1, there is shown a vessel 10 which is a vertical reactor of the type employed for the direct reduction of iron oxides. At the top of the container 10, solids made of fine iron ore are supplied into the container 10 through the solids inlet 12. The reduced iron ore is removed from the bottom of vessel 10 via solids outlet 14. A fluidizing gas in the form of a hot reducing gas is supplied into the bottom of the vessel 10 via a fluidizing gas inlet 16. The used reducing gas is recovered from the top of the container 10 via the line 18.

The container 10 is formed by the wall means 20.
Is divided into a fluidized powder section 22 at the upper part of the fluidizer and a fluidizing gas supply section 24 at the lower part of the wall means 20.

The fluidizing gas supplied from the fluidizing gas inlet 16 is supplied to the fluidizing gas supply section 24 through the wall means 2.
A baffle 26 is provided near the downstream of the inlet 16 for distribution toward a plurality of nozzles 28 provided at zero. As mentioned above, the baffle 26 is
Cause a preferential cross flow at the inlet of the outer ring of the nozzle 28 provided at Thereby, the outer ring wall 3 of the nozzle
Accumulation of fines on the zero part occurs. To avoid this phenomenon, at least the outer ring of the nozzle 28 in the wall means 20 has individual plates (plates) for redirecting the fluidizing gas and for better distribution of the fluidizing gas flow through the nozzle 28. Member 32 is provided.

Referring to FIG. 2, the design of the nozzle of the present invention will be described in detail below. Each of the nozzles 28, or at least the nozzles that comprise the outer ring of the nozzles 28 in the wall means 20, may be provided with a nozzle to redirect the flow of the fluidizing gas to achieve a uniform flow of the fluidizing gas through the nozzle. The plate 32 is provided near the entrance opening 34. According to the invention, the plate 32 has a diameter Dp larger than the diameter Di of the nozzle 23. In order to efficiently redirect the flow of fluidizing gas to the inlet 34 of the nozzle 28 without adversely affecting access to the plate, the plate 32 must be spaced a relatively short distance H from the inlet 34 of the nozzle. I learned what to do. The combination of the plate diameter Dp and the distance H ensures an optimal flow of the fluidizing gas through the nozzle 28. The nozzle 28 is of a conical shape with side walls forming an angle α to ensure acceleration of the fluidizing gas passing through the nozzle and to further prevent fines from adhering to the inner surface of the nozzle. The combination of the shape and size of the nozzle 28 and the size and position of the plate 32 with respect to the nozzle inlet 34 ensure an optimal fluidizing gas flow.

In accordance with the present invention, a conical nozzle having a length between about 330 mm and about 450 mm, an inlet diameter Di between about 100 mm and about 120 mm, an outlet diameter Do between about 35 mm and about 45 mm, It has also been found that an angle α between about 5 ° and about 8 ° is particularly useful and preferred in fluidized bed reactors used in direct reduction of iron oxides. In such a nozzle design, the plate 32 is connected to the inlet 32 and the nozzle 28 from about 125 mm to about 225 mm.
mm and a diameter D of the plate 32
It has been found that p should be between about 150 mm and about 230 mmd. The design of the plate 32 with respect to the nozzle 28 as described above allows the redirection of the fluidizing gas and the flow of the fluidizing gas through the nozzle 28 to be optimized.

Although the dimensions of the nozzle are preferably in the above ranges, the nozzle should maintain the following dimensional relationship: That is, the ratio (Di-Do) / L is between 0.175 and 0.281, the ratio (Di / Do) is between 2.6 and 4.8, and the angle α is between about 5 ° and about 8 °. while. With such a noise design, the plate 32 should be positioned at a distance H from the inlet 34 of the nozzle 28 based on a ratio (L / H) that is between 2 and 4.1;
It can also be seen that the ratio (Dp / Di) between the plate diameter Dp and the inlet diameter Di is between 1.3 and 1.6.

In accordance with the present invention, the plate 32 is provided with a desired distance H by a plurality of support members in the form of rods 36 secured to the nozzle at angular intervals of about 120 ° as illustrated in FIG. It is fixed with. The rod 36 is fixed to the nozzle and the plate 32 by brazing or the like. Preferably, the rod 36 is made as small as possible so as to provide the necessary support for the plate 32 on the nozzle 28 and at the same time not prevent access of the fluidizing gas to the inlet of the nozzle 28.

The nozzle design of the present invention ensures smooth access to the inlet 34 of the nozzle 28 by the fluidizing gas, eliminates the problem of strong lateral flow at the inlet of the nozzle, and reduces the problem on the outer surface of the nozzle, especially the wall member. The selective accumulation of fines in the noise at the outer ring 20 can be eliminated.
According to the invention, all nozzles can be provided with a plate according to the invention, but in certain applications it may be necessary to provide a plate 32 only for nozzles on the outer ring side. As described above, the embodiment of the present invention has been described.
These embodiments are merely exemplifications of the best mode for carrying out the present invention, and can be appropriately changed in shape, arrangement of components and details of operation, etc., and therefore, the present invention is not limited to these exemplified embodiments. There is no restriction. The present invention includes all such modifications that fall within the technical concept and scope defined in the claims.

[Brief description of the drawings]

FIG. 1 is a schematic illustration of a fluidized bed type container illustrating an improved nozzle structure of the device according to the invention.

FIG. 2 is an enlarged view of a nozzle design according to the present invention.

FIG. 3 is a sectional view taken along line 3-3 in FIG. 2;

[Explanation of symbols]

 Reference Signs List 10 container 12 solid inlet 14 solid outlet 16 fluidized gas inlet 18 line 20 wall means 22 fluidized powder section 24 fluidized gas supply section 26 baffle 28 nozzle 30 wall 32 plate

──────────────────────────────────────────────────続 き Continuation of the front page (56) References JP-A-63-101697 (JP, A) Table 2-2-504547 (JP, A) (58) Fields investigated (Int. Cl. ⁶ , DB name) B01J 8/18-8/46

Claims (21)

(57) [Claims] 1. A reactor for use in a fluidized powder system, comprising: a vessel defining a flow path for the fluidized powder; a powder for introducing the powder into the vessel in a first direction. Body fluid inlet means for introducing fluidizing gas into the vessel in a second direction substantially counter-current to the first direction, the fluidized powder from the vessel. A fluidizing gas outlet means for removing the fluidizing gas from the container; and a fluidizing gas supply section for dividing the container into a fluidizing powder section and a fluidizing gas supply section. A wall means disposed in the vessel between the powder inlet means and the fluidizing gas inlet means, comprising a plurality of nozzles disposed in the wall means, each of the plurality of nozzles An inlet and an outlet for communicating a fluidizing gas from the fluidizing gas supply section to the fluidized powder section, and distributing a fluidizing gas supply from the fluidizing gas inlet means to the plurality of nozzles. Baffle means disposed between said side wall means and said fluidizing gas inlet means in said fluidizing gas supply section, and said fluidizing gas flow through at least some of said plurality of nozzles A plate means spaced apart near at least some of the inlets of the plurality of nozzles for redirecting. 2. The plurality of nozzles have a conical shape having an inlet diameter Di and an outlet diameter Do, wherein Di is D
2. The reactor according to claim 1, wherein the reactor is larger than o. 3. The apparatus according to claim 2, wherein said plate means has a diameter Dp.
3. The reactor according to claim 2, wherein p is larger than Di. 4. The reactor of claim 1 including support means fixed to said nozzle for supporting said plate means at a distance H above the inlet of said nozzle. 5. The reactor according to claim 4, wherein H is between about 125 mm and about 225 mm. 6. The reactor of claim 4 wherein said support means comprises three rods secured to said nozzle at angular intervals of about 120 °. 7. The reactor of claim 2 wherein the conical nozzle has a side wall defining an angle α between about 5 ° and about 8 °. 8. The method according to claim 1, wherein Do is between about 35 mm and about 45 mm, Di is between about 100 mm and about 120 mm, and the nozzle has a length L between about 330 mm and about 450 mm.
The reactor according to claim 2, comprising: 9. The reactor according to claim 3, wherein Dp is between about 150 mm and about 230 mm. 10. The method according to claim 1, wherein Do is between about 35 mm and about 45 mm, Di is between about 100 mm and about 120 mm, and the nozzle has a length L between about 330 mm and about 450 mm. The reactor according to claim 3. 11. Dp is from about 150 mm to about 230 mm
The reactor according to claim 10, wherein 12. The apparatus according to claim 11, further comprising support means fixed to said nozzle for supporting said plate means at a distance H thereabove above the inlet of said nozzle.
A reactor as described. 13. The reactor according to claim 12, wherein H is between about 125 mm and about 225 mm. 14. The method of claim 1, wherein the conical nozzle is about 5 ° to about 8 °.
14. The reactor according to claim 13, having a side wall forming an angle α between them. 15. The reactor according to claim 4, wherein the ratio (L / H) is between 2 and 4.1, and L is the length of the nozzle. 16. The ratio (Di / Do) of 2.6 to 4.
3. The reactor according to claim 2, wherein the distance is between eight and eight. 17. The ratio (Dp / Di) is from 1.3 to 1.
6. The reactor according to claim 3, wherein the distance is between 6 and 6. 18. The ratio (Di / Do) of 2.6 to 4.
The reactor according to claim 3, characterized in that it is between 8 and 8. 19. The ratio (Dp / Di) is from 1.3 to 1.
A reactor according to claim 10, characterized in that it is between 6 and 6. 20. The reactor according to claim 12, wherein the ratio (L / H) is between 2 and 4.1. 21. The ratio (Di-Do) / L is 0.175.
The reactor of claim 2, wherein L is the length of the nozzle.