JPH06300457A - Powder fluidized bed - Google Patents

Abstract

PURPOSE:To provide a powder fluidized bed capable of being operated for a long period of hour using powder and in particular fine powder as material. CONSTITUTION:The powder fluidized bed is provided with a hollow body 6, with a number of gas blowout holes 7 open downward, mounted to the lower part of a retort fixedly or in a rotatable manner and, as required, with a stirring rod 11 mounted to the upper part of the long-size hollow body 6.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION This invention relates to the oxidation, reduction,
The present invention relates to a powder fluidized bed used for thermal decomposition reaction and powder drying or granulation.

[0002]

2. Description of the Related Art Generally, as shown in FIG. 6, a fluidized bed comprises a retort 1 having a number of small holes 2 provided in a lower portion of a retort plate 3.
The powder 5 is charged from above the retort 1 and is made to flow by the gas blown up through the dispersion plate 3.

At this time, when the powder 5 comes into contact with the disperser 3 and adheres to the holes 2 of the disperser 3, the coarse particles that are not blown up by the gas flow are placed on the disperser 3. The coarse particle layer 4 is formed, and the coarse particle layer 4 forms a powder 5
Are prevented from contacting the dispersion plate 3.

[0004]

By providing the coarse particle layer 4, it is possible to prevent the powder charged in the retort 1 from coming into contact with the dispersion plate 3 and blocking the hole 2 to some extent.
When the powder is fine powder, a part of the powder may reach the dispersion plate 3 through the grain gaps of the coarse grain layer 4 and still block the holes 2 to make uniform gas ejection impossible. The hole 2 may be closed even after performing the time operation or the continuous operation.

Therefore, in the conventional fluidized bed of this kind of structure, it is always necessary to clean the dispersion platen 3, and there is a tendency to avoid long-term operation or continuous operation. Therefore, high-efficiency operation of the fluidized bed is impossible. It was

Further, the coarse particles constituting the coarse particle layer 4 are not blown up by the gas flow, but are worn by vibrating while vibrating while contacting each other, and the fine powder generated by this abrasion is treated as impurities. A new problem of mixing in the powder 5 has also arisen.

[0007]

Therefore, the present inventors have
While conducting research to develop a fluidized bed that does not contain impurities and that does not clog holes even after continuous operation for a long time, a gas that opens toward the bottom of the retort is opened. A fluidized bed, in which a hollow body having ejection holes is attached and the gas ejected from the gas ejection holes is ejected toward the bottom of the retort, there is no risk of impurities being mixed in since there is no need to provide a coarse particle layer, and The research result was obtained that the gas ejection holes were not blocked even when the fine powder was continuously operated for a long time.

The present invention has been made based on the results of such research, and is characterized by a powder fluidized bed in which a hollow body having a large number of gas ejection holes opened downward is provided in the lower portion of the retort.

Although it is not always necessary to rotate the hollow body, it is preferable to rotate the hollow body at an appropriate speed when the fluidity of the powder is poor or when it is necessary to further homogenize the ejected gas. At this time, the above effect is further improved by attaching a stirring rod on the hollow body and rotating the stirring rod simultaneously with the rotation of the hollow body.

The hollow body is not particularly limited as long as it has a structure having a hollow portion for supplying gas and a gas ejection hole communicating with the hollow portion and opening downward.

[0011]

The structure and operation of the powder fluidized bed of the present invention are shown in FIG.
~ It will be described in more detail based on FIG.

FIG. 1 is a cross-sectional view of the most representative powder fluidized bed of the present invention. The hollow body 6 is composed of a long pipe having a gas ejection hole 7 and is attached to a gas introduction pipe 8. The hollow portion 9 of the hollow body 6 communicates with the hollow portion 10 of the gas introduction pipe 8, and the gas introduced through the hollow portion 10 of the gas introduction pipe 8 passes through the hollow portion 9 of the hollow body 6. The gas is ejected from the gas ejection hole 7 toward the bottom surface of the retort 1.

The gas introducing pipe 8 is preferably rotatably attached to the lower portion of the retort 1, but may be fixed so as not to be rotatable.

FIG. 2 shows a back view of the hollow body 6, and the hollow body 6 is preferably curved as shown in FIG. 2 (a), but it may not be curved. Further, a ring pipe can be attached as shown in FIG. However, the shape and structure of the hollow body 6 is
The gas ejection hole 7 is not limited to the one illustrated in FIG. 2 and has a cross-sectional shape having a hollow portion 9.
Any structure may be used as long as it has a structure.

Further, in the case of fine powder having a remarkably poor fluidity or when the height of the fluidized bed itself is large, a bad fluidized state such as channeling or slacking may occur. In such a case, if the necessary number of stirring rods 11 are rotated integrally with the hollow body 6 as shown in FIG. 3, the channeling and slacking are destroyed and can be prevented in advance.

Further, as shown in FIG. 4, the hollow body 6 can be fixedly or rotatably attached to the tip of the gas introduction pipe 8 lowered from above the retort 1, and as shown in FIG. It may be mounted by connecting and fixing it to the guy introducing pipe 8 mounted around the retort 1.

[0017]

【Example】

Example 1 Stainless steel (SUS310) plate, diameter: 450:
m, height: 1800 m, a cylindrical retort was made, a gas introduction pipe with an inner diameter of 15 mm was rotatably attached to the lower part of the retort, and a diameter of 1.5 mm was provided at the upper end of the gas introduction pipe.
Length with a hollow part with 20 gas ejection holes: 21
Three 0 mm hollow stainless steel hollow pipes were radially attached to prepare the powder fluidized bed of the present invention having the structure shown in FIG.

Pure iron fine powder having an average particle diameter of 1.2 μm was charged into this powder fluidized bed, and the gas introduction tube was rotated at a rotation speed of 50.
While rotating at rpm, hot air at a temperature of 140 ° C. was supplied to the hollow portion of the gas introduction pipe at a flow rate of 500 l / min for 1.0 hour, and the pure iron fine powder was continuously dried 20 times. The gas ejection hole of the hollow pipe was never blocked.

Example 2 On the hollow pipe of the powder fluidized bed produced in Example 1, three stirring rods were further attached to prepare the powder fluidized bed of the present invention having the structure shown in FIG. The layer was used to dry pure iron fine powder having an average particle diameter of 1.2 μm under the same conditions as in Example 1, but no blockage of gas ejection holes was observed.

Example 3 A gas introducing pipe having an inner diameter of 15 mm was lowered from the upper part of the retort produced in Example 1 so that the tip reached near the bottom of the retort, and the tip of this gas introducing pipe was made of the same stainless steel as in Example 1. Attach three hollow pipes so that they can rotate radially,
The pure iron fine powder was dried under the same conditions as in Example 1, but the gas ejection holes were not blocked.

Example 4 Three gas introducing pipes were attached to the bottom of the retort produced in Example 1 by welding, and the diameter of the gas introducing pipe was 1.5 mm.
Figure 5 shows a stainless steel hollow pipe with a gas projecting hole.
As shown in (3), the gas protruding holes were attached so as to face downward to prepare the powder fluidized bed of the present invention.

Cobalt hydroxide powder having an average particle size of 6.2 μm was charged in this fluidized bed, and hot air at a temperature of 330 ° C. was supplied to the hollow portion of the gas inlet tube at a flow rate of 300 l / min for 1.0 hour. Then, the cobalt hydroxide powder was thermally decomposed,
The gas ejection holes of the hollow pipe were never blocked.

On the other hand, for comparison, a conventional powder fluidized bed having substantially the same volume of retort was used, and cobalt hydroxide powder having the same average particle diameter was charged into the conventional powder fluidized bed under the same conditions. Then, hot air was supplied to perform thermal decomposition of the cobalt hydroxide powder, and the holes in the dispersion plate were examined.
It was discovered that 0% of the holes were closed.

[0024]

As described above, the powder fluidized bed of the present invention requires substantially no cleaning of the gas ejection holes even if a fine powder is used as the raw material powder for a long period of operation. In addition, since the coarse grain layer is not used, the mixing of impurities is significantly reduced, which is a remarkable effect.

[Brief description of drawings]

FIG. 1 is a cross-sectional view of a powder fluidized bed of the present invention.

FIG. 2 is a back view of the hollow body attached to the powder fluidized bed of the present invention, which has the structure shown in (a) or (b).

FIG. 3 is a cross-sectional view of the powder fluidized bed of the present invention.

FIG. 4 is a cross-sectional view of the powder fluidized bed of the present invention.

FIG. 5 is a cross-sectional view of the powder fluidized bed of the present invention, (b)
It is shown that the hollow body shown in (a) is fixed as shown in (a).

FIG. 6 is a sectional view of a conventional powder fluidized bed.

[Explanation of symbols]

 1 Retort 2 Hole 3 Disperser 4 Coarse Grain Layer 5 Powder 6 Hollow Body 7 Gas Injection Hole 8 Gas Introducing Tube 9 Hollow Part of Hollow Body 10 Hollow Part of Gas Introducing Tube 11 Stirring Bar

[Procedure amendment]

[Submission date] June 3, 1993

[Procedure Amendment 1]

[Document name to be amended] Statement

[Correction target item name] 0016

[Correction method] Change

[Correction content]

Further, as shown in FIG. 4, the hollow body 6 can be fixedly or rotatably attached to the tip of the gas introduction pipe 8 lowered from above the retort 1, and as shown in FIG. it may be attached to connect fixed and gas <br/> inlet tube 8 mounted around the retort 1.

[Procedure Amendment 2]

[Document name to be amended] Statement

[Correction target item name] 0017

[Correction method] Change

[Correction content]

[0017]

Example 1 A stainless steel (SUS310) plate with a diameter of 450 m
m 2 , height: 1800 mm, a cylindrical retort was prepared, and a gas inlet pipe having an inner diameter of 15 mm was rotatably attached to the lower portion of the retort, and a diameter of 1.5 mm was provided at the upper end of the gas inlet pipe.
Length with a hollow part with 20 mm gas ejection holes: 2
Three 10 mm hollow stainless steel pipes were radially attached to prepare a powder fluidized bed of the present invention having the structure shown in FIG.

Claims (4)

[Claims] 1. A powder fluidized bed characterized in that a hollow body having a large number of downwardly opened gas ejection holes is provided in the lower part of the retort. 2. The powder fluidized bed according to claim 1, wherein the hollow body is rotatably attached to a lower portion of the retort. 3. The powder fluidized bed according to claim 2, wherein a stirring rod is attached to the upper part of the hollow body. 4. The powder fluidized bed according to claim 1, wherein the hollow body is assembled by connecting pipes.