JPH09150051A - Gas dispersing device for fluidized bed - Google Patents

Abstract

PROBLEM TO BE SOLVED: To certainly prevent the falling of particles by simple constitution. SOLUTION: A perforated plate having holes 4a supplying gas for a fluidized bed formed thereto is provided to the bottom part of a fluidizing chamber forming solid-gas flow. A support plate 5 is provided under the perforated plate and a plurality of cylindrical gas supply means 6 pierce the support plate so that they are not overlapped with the holes of the perforated plate and the upper end parts of them protrude upwardly from the support plate. The upper openings 6a of the clindrical gas supply means are arranged at the position above the piling slope 8 of particles 7 falling from the holes of the perforated plate to be piled up on the support plate at a predetermined angle of repose.

Description

Detailed Description of the Invention

[0001]

TECHNICAL FIELD The present invention relates to a gas dispersion device for a fluidized bed of solid particles in a fluidized bed reactor, a fluidized bed dryer or the like.

[0002]

2. Description of the Related Art Gas distributors for fluidized bed reactors include cap type, manifold type, orifice type, sintered plates, and porous plates. The reaction rate and selectivity in a fluidized bed reactor (bubble fluidized bed) are affected by the size of bubbles. In particular, in a system with a slow reaction rate, a small bubble diameter is desired in order to increase the reaction rate and the like. Generally, in order to generate a small bubble diameter, a sintered plate or a perforated plate having many gas ejection holes is used for the gas disperser. However, the sintered plate is apt to be clogged with particles and is not suitable for large-scale processing. For this reason, generally, a porous plate is used to generate small bubble diameters for industrial equipment.

A fluidized bed gas disperser using a perforated plate has a problem that particles forming the fluidized bed fall downward from the holes of the perforated plate. As a method for dealing with such a problem, for example, Japanese Patent Application Laid-Open No. 62-201634 discloses a technique in which a lower porous plate is arranged below a porous plate in a shifted manner so that holes do not overlap with each other. Further, in Japanese Patent Application Laid-Open No. 3-193134, a cylindrical particle receiving member is arranged below a hole of a perforated plate, particles falling downward from the hole are received by the particle receiving member, and a further particle from the hole is received. A technique for preventing particles from falling is also disclosed.

[0004]

In any of the above-described conventional fluidized bed gas dispersers, there is a problem in that it is not possible to completely prevent the particles from falling through the holes. That is, in the former technique, the lower porous plate is further provided below the porous plate,
For example, when the lower porous plate is arranged in consideration of the angle of repose of the particles falling and accumulated from the holes of the porous plate, the diameter or shape of the particles on the porous plate is not uniform, and in the case of small-diameter particles,
There is a problem of dropping further downward from the holes of the lower porous plate.
Such a problem may similarly occur when vibration or the like occurs even in the latter technique of disposing the particle receiving member below the holes of the porous plate. In addition, the above-mentioned conventional technique has a problem that it is structurally complicated.

The present invention has been made in view of the above circumstances, and an object thereof is to provide a gas disperser for a fluidized bed, which has a simple structure and can reliably prevent particles from falling.

[0006]

In order to achieve the above object, in the invention described in claim 1, a hole for supplying a fluidized-bed gas is formed at the bottom of a fluid chamber which forms a solid-gas flow. In a fluidized bed gas disperser having a perforated plate, a support plate is provided below the perforated plate, and a plurality of cylindrical gas supply means penetrates through the support plate and overlaps with holes of the perforated plate. It is characterized in that each upper end portion of the cylindrical gas supply means is provided so as to protrude upward from the support plate so as not to become the above. In the invention according to claim 2, the upper opening of the cylindrical gas supply means is arranged at a position higher than a deposition slope of particles that fall from the holes of the perforated plate and are deposited on the support plate at a predetermined angle of repose. It is characterized by

According to the present invention, during operation, the particles are blown up from the holes to above the perforated plate by the flow of gas, and the particles do not fall from the holes. When the operation is stopped, particles fall downward from the holes of the perforated plate, and the falling particles are deposited on the support plate at a predetermined angle of repose.
At this time, since the plurality of tubular gas supply means penetrates through the support plate and their upper ends project upward from the support plate, the wall portions of the tubular gas supply means themselves function as weirs. This means that particles will not drop downward from these gas supply means.

[0008]

BEST MODE FOR CARRYING OUT THE INVENTION Embodiments of the present invention will be described below with reference to FIGS. In FIG. 1, reference numeral 1 is a fluidized bed reactor having a gas inflow hole 1a in the lower part and a gas outflow hole 1b in the upper part. Reference numeral 2 denotes a fluidized bed gas disperser according to the present invention, which is provided at the bottom of the fluidized chamber 3 below the fluidized bed reactor 1 so as to form a solid-gas flow.

The fluidized bed gas disperser 2 comprises a perforated plate 4 arranged at a predetermined height in the reactor 1 along a substantially horizontal plane,
A support plate 5 is disposed below the support plate 5 and is arranged substantially in parallel at a predetermined interval. As shown in FIG. 2, the perforated plate 4 is regularly formed with a large number of holes 4a, ... For supplying the fluidized-bed gas from below to above the fluidized chamber 3. On the other hand, the support plate 5 is provided with a plurality of cylindrical gas supply means 6 ,.
Is provided so as not to overlap the holes 4a of the perforated plate 4 and the upper ends of the tubular gas supply means 6 project upward from the support plate 5. Perforated plate 4
2 (a) shows an example of the arrangement of the holes 4a of FIG. 2 and the gas supply means 6 formed on the support plate 5 therebelow.
Those shown in (b) and (c) are also conceivable. These Figure 2
In the structure shown in (b) and (c), the arrangement density of the holes 4a and the gas supply means is set to be the same. Further, the upper opening 6a of the cylindrical gas supply means 6 has a porous plate 4 as shown in FIG.
Falling from the holes 4a, ...
Are arranged above the deposition slope 8 of the particles 7 ,.

The holes 4a formed in the perforated plate 4 have a uniform diameter and a diameter of 1 to 5 mm, although they vary depending on various conditions such as the diameter of the particles for fluidized bed arranged on the perforated plate 4. Those that are set are preferable, and the opening area ratio is 1 to 10%
Those set to are preferable. The cylindrical gas supply means 6 provided on the support plate 5 has a uniform diameter, which is larger than the diameter of the hole 4a, and is 3 to 10 m.
It is preferable to use a pipe material having a circular cross section set to about m. Further, the distance n between the porous plate 4 and the upper end of the cylindrical gas supply means 6 provided on the support plate 5 is determined by the gas supply means 6
It is preferable to set the diameter to about 1/4 to 1 of the diameter of the pipe material constituting the. When the holes 4a of the perforated plate 4 and the gas supply means 6 of the support plate 5 are viewed from the operating condition, the flow velocity of the gas passing through the holes 4a is preferably set to 5 to 80 m / sec, and 10 to 60 m / sec. It is more preferable to set to. The flow velocity of the gas passing through the tubular gas supply means 6 is preferably set to 2.5 to 80 m / sec, more preferably 5 to 60 m / sec.
Further, the ratio of the flow velocity of the gas passing through the hole 4a and the flow velocity of the gas passing through the tubular gas supply means 6 is preferably 1: 0.5 to 1. The flow velocity of the gas passing through the fluidized bed reactor 1 is preferably set to 5 to 300 cm / sec.

More specifically, for example, when the fluidized bed particles placed on the porous plate 4 are FCC catalysts, the holes 4a of the porous plate 4 having a uniform diameter of 3 mm are used. A pipe material having a diameter of 6 mm and a length of 20 mm is used for the tubular gas supply means 6 of the support plate 5, and the distance n between the porous plate 4 and the upper end of the pipe material provided on the support plate 5 is 5 mm. 2 and the holes 4a of the perforated plate 4 are shown in FIG.
As shown in (a), they are arranged at a distance of about 20 mm from each other so that they are located at the vertices of an equilateral triangle. Also,
The velocity of the gas flowing in the fluidized bed reactor 1 at this time is 20
The angle of repose θ of the FCC is 32 °. The angle of repose θ is 39 ° when the particles 7 placed on the porous plate 4 are alumina. The repose angle θ of carbon black is 35 °, the repose angle θ of glass beads is 15 °, and the repose angle θ of silica gel is 50.
And the diameter of the particles is 10 to 1000 μm.
It is about.

According to the fluidized bed gas disperser having the above construction, however, gas is introduced into the fluidized bed reactor 1 through the gas inlet hole 1a at the bottom of the fluidized bed reactor 1 during operation, as shown in FIG. As shown in the drawing, after the gas supply means 6 is blown upward, the flow is changed to the side and further passes through the holes 4, ... To the outside. At this time, the gas is always in the holes 4 of the perforated plate 4.
Since it flows upward in a, it is pushed back by this gas flow, so that the particles 7 on the porous plate 4 do not fall downward from the holes 4a.

On the other hand, when the operation is stopped, the particles 7 on the perforated plate 4 fall downward through the holes 4a, ... As shown in FIG. 4, and the falling particles fall on the support plate 5 at a predetermined angle of repose. θ
To deposit. At this time, the plurality of cylindrical gas supply means 6 provided on the support plate 5 have upper end portions projecting upward from the support plate 5, and are provided at positions that do not overlap the holes 4a of the perforated plate 4. And the upper end portion thereof is located above the deposition slope 8 of the particles 7 deposited on the support plate 5, the wall portion itself of the gas supply means 6 having such a cylindrical shape is a weir. As a result, the particles 7 deposited on the support plate 5 do not fall downward from the gas supply means 6.

The fluidized bed gas disperser of the present invention is not limited to the above-described embodiment, and is provided in the shape of the fluid chamber 3, or in the holes 4a formed in the perforated plate 4 and the support plate 5. The shape and the like of the gas supply means 6 can be variously changed. For example, in the above-described embodiment, the fluidized bed gas disperser 2 assembled to the fluidized bed reactor 1 has been described as an example, but the present invention is not limited to this, and the fluidized bed dryer also includes the fluidized bed of the present invention. A bed gas disperser is applicable. Further, in the above embodiment, a pipe having a circular cross section is used as the gas supply means 6 provided on the support plate 5, but the present invention is not limited to this, and if the pipe is tubular, the cross section may be a square, a triangle, or any other shape. A rectangular tubular body may be used as the gas supply means 6.

[0015]

As described above, the present invention has the following excellent effects. According to the first aspect of the invention, the support plate provided below the perforated plate is provided with a plurality of tubular gas supply means so as to penetrate the support plate and not overlap the holes of the perforated plate, and the tubular plate has a tubular shape. Since each upper end of the gas supply means is provided so as to project upward from the support plate, the wall portion of the tubular gas supply means itself functions as a weir, and the operation is performed despite the simple structure. The particles do not fall downward from the gas supply means when stopped. According to the invention of claim 2, the upper opening of the cylindrical gas supply means is arranged at a position higher than the deposition slope of the particles that fall from the holes of the perforated plate and are deposited on the support plate at a predetermined angle of repose. Therefore, it is possible to more reliably prevent the particles from dropping downward from the gas supply means.

[Brief description of the drawings]

FIG. 1 is a sectional view of a fluidized bed reactor equipped with a fluidized bed gas disperser according to the present invention.

FIG. 2A is a view seen from the direction A in FIG. 1, and FIG.
FIG. 6 is a diagram showing another arrangement example of the holes of the perforated plate and the gas supply means of the support plate, and (c) is a diagram showing still another arrangement example of the holes of the perforated plate and the gas supply means of the support plate.

FIG. 3 is a cross-sectional view showing the behavior of the fluidized bed gas disperser of FIG. 1 during operation.

FIG. 4 is a cross-sectional view showing the behavior of the fluidized bed gas disperser of FIG. 1 when the operation is stopped.

[Explanation of symbols]

 1 Fluidized Bed Reactor 2 Gas Disperser for Fluidized Bed 3 Fluidized Chamber 4 Perforated Plate 4a Hole 5 Support Plate 6 Gas Supply Means 7 Particles 8 Slope

Claims (2)

[Claims] 1. A gas dispersion for a fluidized bed having a perforated plate (4) having holes (4a) for supplying a gas for a fluidized bed formed in a bottom portion (3a) of a fluidized chamber (3) forming a solid-gas flow. In the vessel (2), a support plate (5) is provided below the perforated plate, and a plurality of cylindrical gas supply means (6) penetrates the support plate and overlaps with the holes of the perforated plate. The gas disperser for a fluidized bed, characterized in that each upper end portion of the cylindrical gas supply means is provided so as to not protrude from the support plate upward. 2. The fluidized bed gas disperser according to claim 1, wherein the upper opening (6a) of the cylindrical gas supply means falls from the hole of the perforated plate and has a predetermined angle of repose on the support plate. A gas disperser for a fluidized bed, which is arranged at a position higher than a deposition slope (8) of particles (7) to be deposited.