JPH0153571B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a stirring device used for mixing, stirring and cooling of powder and granular materials, solid-gas reactions, solid-solid reactions, solid decomposition reactions, production of powder and granular polymers, and the like.

Reactors for this purpose generally require a high mixing speed between powders and granules, good contact between the gas or liquid substance and the powders, and heat transfer ability of the powders. Various performance requirements are required, such as a large thermal area x heat transfer coefficient), a high rate of separation of generated gas and steam from powder and granules, and a small amount of powder and granules accompanying the gas. A fluidized bed reactor (hereinafter simply referred to as a fluidized bed), which fluidizes powder by blowing, is widely used.

However, fluidized beds require a large amount of gas to be blown or circulated, and not only do they require a large-capacity compressor, its power, and a device to remove fines accompanying the gas, but they also require a large amount of gas to be blown for fluidization. It cannot be applied to reaction systems that dislike crowding.

For this fluidized bed, a device (hereinafter referred to as a stirred fluidized bed) that forms a fluidized state substantially similar to that of a fluidized bed by only mechanical stirring and has the same characteristics as a fluidized bed (hereinafter referred to as a stirred fluidized bed). Publication No. 55-157605 and No. 57-
Publication No. 73011, Rapid Dryer,
FORBERG instant mixer) is known. However, in an agitated fluidized bed, when a conductive heat exchange member is inserted into the bed, the shape and arrangement of the heat exchange member significantly affect the flow, so contact between the heat exchange member and the granular material is In order to bring it into a favorable state,
In addition, in the case of particles with high adhesiveness or stickiness, there are restrictions on the shape and arrangement of the heat exchange member in order to forcibly scrape off the powder that adheres to the surface of the heat exchange member. big.

As a conductive heat exchange member inserted into an agitated fluidized bed, thin tubes configured in a loop shape such as a U shape or a spiral shape are conventionally known (Japanese Unexamined Patent Publication No. 73011/1989). However, as a result of studies, the inventors found that a configuration in which a disc-shaped member is connected to a rotating shaft in the form of a bead is suitable. Conventionally, such a hollow disk-shaped heat exchange member through which a heat exchange medium flows has been rotated at a relatively low speed in a stirring device for powder and granular materials for purposes such as drying. known (for example, Tsukishima Kikai, rotary disc groove dryer; Tamagawa Kikai, disc dryer; Hosokawa Micron, Taurus Disk; Nara Kikai, paddle dryer). These stirring devices use paddle-shaped stirring blades provided on the outer periphery of a disk-shaped member for heat exchange to flow the powder and granular material, but in all cases, the width of the stirring blade is narrow;
Even if the rotation speed is increased, it is not possible to obtain the intense fluidization of powder and granules as in an agitated fluidized bed, which greatly limits the mixing speed and heat exchange efficiency of powder and granules. There is a problem that powder particles tend to adhere to the surface of the member.

The present invention provides a stirring device for powder and granular materials that solves the problems of known stirring devices.

That is, in the present invention, two rotating shafts to which a disc-shaped member through which a heating or cooling medium flows are provided laterally through the end wall of the container body, A stirring blade is attached to the disc-shaped member, and the disc-shaped member has a conical shape with a large thickness at the part where it is attached to the rotating shaft and a small thickness at the part where the stirring blade is attached. A protruding chamber extending in the axial direction is provided in communication with the container body so that both ends of the protruding chamber are at the center of the rotating shaft or inside thereof,
This is a powder stirring device characterized in that the bottom and side portions of the container body are constructed of a partial cylinder along the locus of the tip of a stirring blade.

The stirring device of the present invention has the following excellent features.

By rotating two-shaft stirring blades at high speed, for example, in the directions shown in Figure 2 (the number and direction of rotation are not limited to these), the powder and granules are A stirred fluidized bed exhibiting a flow pattern (hereinafter referred to as forced circulation flow) in which the flow rises along both side walls parallel to the flow, violently collides and merges in the center of the container, and descends is formed. This stirred fluidized bed has characteristics comparable to conventional fluidized beds, in particular, the heat transfer rate between the powder and the heat exchange disc-shaped member is high, and the mixing and stirring of the powder and granule is good. For example, the liquid added as a reactant if necessary can be quickly dispersed, and there is little temperature unevenness in the powder or granular material.

The flow of powder and granules in forced circulation flow is extremely stable, and the range in which the hold-up of the powder and granules in the container and the physical properties of the powder and granules, such as particle size, wetness, and viscosity, can be controlled is very high. is wide.

Since the protrusion chamber is formed in the upper part of the container body, the gas supplied to the container body or the gas generated within the container body crosses at right angles to the direction of movement of the powder and granules and is discharged into the protrusion chamber. . Furthermore, since the movement speed of the powder by the stirring blade is higher than the exhaust gas speed, the amount of powder and granules entrained in the exhaust gas is extremely small.

Next, the present invention will be explained based on drawings showing one embodiment thereof.

A jacket 2 is attached to the container body 1 to allow a heating or cooling medium to flow therethrough, as required. Two rotating shafts 3a and 3b are provided laterally through both end walls of the container 1. Rotating axis 3
a and 3b are supported by bearings 4. Rotating axis 3
It is preferable that a and 3b are provided parallel to each other.
The spacing between the rotating shafts 3a and 3b is determined by the stirring blade 7, which will be described later.
It is preferable that the trajectories (rotating circles) of the tips of a and 7b are close to each other or overlap.

Disc-shaped members 5a, 5b through which a heating or cooling medium flows are attached to the rotating shafts 3a, 3b. Rotating shafts 3a, 3b and disc-shaped members 5a, 5b
For example, as shown in FIG. 3, the inside of the holder has a structure through which a heating or cooling medium flows. A rotary joint 6 is attached to one end of the rotating shafts 3a, 3b for supplying and discharging a heating or cooling medium to the rotating shafts 3a, 3b and the disc-shaped members 5a, 5b. The size and number of the disc-shaped members 5a, 5b can be appropriately determined by those skilled in the art, taking into consideration the amount of heat to be heated or removed. disk-shaped member 5a,
As shown in FIGS. 3 and 5, 5b has a conical shape that is thick at the part where it is attached to the rotating shaft and becomes thinner at the part where the stirring blade is attached. If the shape of the disk-shaped member is a rectangular parallelepiped as shown in FIG. 4, the flow resistance of the powder and granules becomes large during the operation of the apparatus, making it difficult to form a good agitated fluidized bed.

Stirring blades 7a, 7b are attached to the outermost peripheries of the disc-shaped members 5a, 5b. Stirring 7a,
Although there is no particular restriction on the shape of 7b, in order to form a circulating flow of powder and granular material within the container body 1, it is preferable that the flat stirring blades be parallel to the rotating shafts 3a and 3b. In order to promote the movement of the granular material in the direction of the rotation axis of the container 1, the stirring blades 7a and 7b may be inclined with respect to the axial direction, or parallel blades and inclined blades may be combined. stirring blade 7a,
A plurality of blades 7b are installed symmetrically, and three or four blades may also be used, but two blades are usually sufficient. The stirring blades 7a and 7b are attached so that both blades do not come into contact with each other as they rotate. When the width of the stirring blades 7a, 7b relative to the radius of rotation becomes larger, the radius of the disc-shaped members 5a, 5b becomes smaller.
Since the heat transfer area becomes small, it is desirable that the heat transfer area be small as long as a circulating flow of the powder and granular material is formed.

A projecting chamber 10 is formed in the upper part of the container body 1 by a side wall 8 and a ceiling wall 9 provided at or inside the center of the rotating shafts 3a, 3b. The side wall 8 is preferably provided in a vertical position as shown. The distance (L) between both side walls 8 is the rotation axis 3
It is preferably 0.5 to 1 times the distance (L) between axes a and 3b. The height (L) of the protruding chamber 10 is preferably 0.5 to 1 times the above L.

The bottom and sides of the container body 1 are provided with stirring blades 7a, 7.
It is composed of a partial cylinder that follows the trajectory of the tip of b. Stirring blades 7a, 7b are provided at the bottom of the container body 1.
If the trajectories of the tips of the two ends are far apart, it is preferable to provide a chevron-shaped connection part in the middle part. The gap between the inner wall of the container body 1 and the tips of the stirring blades 7a, 7b is preferably as small as possible, and is generally 10 mm or less.

When processing adhesive powder or granular material, as shown in FIG. It is preferable to provide scraping tools 12a and 12b having openings 11 through which the powder and granular material flows close to the outer periphery.

A weir 13 is provided on one end wall of the container body 1, and connected to the weir 13, a powder extraction nozzle 14 is provided. Note that the powder extracting device is not limited to that shown in the drawings, and for example, an extracting nozzle penetrating the jacket 2 may be provided at the bottom of the container body 1.

The length of the container body 1 in the axial direction is arbitrary, but is usually 1 to 7 times the diameter of the rotation angle of the stirring blades 7a and 7b.
In particular, 1.5 to 5 times is appropriate. Although the container 1 is preferably installed horizontally, it can also be installed at an inclination of no more than 10 degrees from the horizontal for the purpose of promoting movement of the powder in the axial direction.

Next, a method of operating the stirring device of the present invention will be explained using formaldehyde polymerization as an example.

Gaseous formaldehyde and a known polymerization catalyst are supplied to the container body 1 through nozzles 20 and 21, respectively. If necessary, the comonomer is supplied to the main body of the container 1 from a nozzle (not shown). Liquefied gas is supplied from the nozzle 22.

The rotating shafts 3a, 3b are rotated at a constant speed by a drive device (not shown). The rotating shafts 3a and 3b may be rotated in any direction, but from the viewpoint of uniformity of stirring, it is preferable to rotate both shafts in opposite directions. In FIG. It is particularly preferred to rotate 3b counterclockwise. The rotational speed of the rotating shafts 3a and 3b is determined by the stirring blade 7.
The tip speed of a and 7b is preferably 1 to 5 m/sec.

The amount of formaldehyde polymer in the container body 1 may be any amount as long as a sufficient stirring effect is obtained, but it is preferably an amount equal to or less than the rotating shafts 3a, 3b when the stirring blades 7a, 7b are stopped. .

In the container 1, the formaldehyde polymer is stirred up by stirring blades 7a and 7b, forming a forced circulation flow.

The heat of polymerization reaction is supplied to the jacket 2 from the nozzle 23 and is discharged from a nozzle (not shown) as a cooling medium, and from the nozzle 24 via the rotating shafts 3a and 3b to the disc-shaped members 5a and 5b, and is discharged from the nozzle 25. removed by the cooling medium. Furthermore, heat is directly removed from the powder by the latent heat of vaporization of the supplied liquefied gas.

In the present invention, the formaldehyde polymer violently collides with the entire disc-shaped members 5a and 5b, and the heat transfer surface itself rotates, so that the sliding force of the powder increases, and the heat transfer surface is uniformly flowed. contact with animals; Therefore, the heat transfer surface can be updated easily, and the heat transfer coefficient can be increased by disturbing the boundary surface.

Furthermore, this device has a high ability to crush powder and granules and mixes the powder well, so the evaporation rate of liquefied gas is high and it is possible to evaporate a large amount of liquefied gas.

The resulting polymer is extracted from the nozzle 14. Unreacted gas and vaporized gas are extracted from the nozzle 26. In the device of the present invention, since the protruding chamber 10 is formed in the upper part of the container body 1, the nozzle 26
It is possible to extremely reduce the amount of powder and granules entrained in the gas discharged from the air.

The case where the stirring device of the present invention is used as a polymerization reactor has been described above, but the stirring device of the present invention can also be used for thermal decomposition reactions of powdery solid materials. In this case, since the powdery solid material forms a stirred fluidized bed, it is easy for the gaseous material produced by the thermal decomposition reaction to move.
This movement can be avoided from controlling the reaction rate. In addition, this device has a large amount of heat transfer per unit volume (heat transfer area x heat transfer coefficient), and it is easy to supply the amount of heat necessary for the pyrolysis reaction. Furthermore, the stirring and mixing are good, so the unit of the device is The amount of reaction per volume is high, and the reaction within the apparatus can be made uniform.

Furthermore, the stirring device of the present invention can be used for mixing various additives such as grains, agricultural chemicals, cement, and synthetic resins, for drying pulverized coal, crystalline ammonium sulfate, and various synthetic resins, and for gas phase polymerization of olefins. In addition, there are mixers for uniformly mixing two or more types of powder or granular materials, reactions between gaseous substances and powder or granular solid materials, reactions between different types of powder or granular solid materials, and mixing of powder or granular solid materials. It can be used as a reactor for decomposition reactions, decomposition reactions of powdery solid materials, and production of powdery polymers.

[Brief explanation of drawings]

FIG. 1 is a schematic diagram of a cross section parallel to the rotation axis of the stirring device of the present invention, FIG. 2 is a schematic diagram corresponding to the A-A cross section of FIG. 1, and FIGS. is a sectional view of the disc-shaped member, FIG. 4 is a sectional view of the disc-shaped member for comparison, and FIG. 6 is a schematic diagram showing the relative positional relationship between the disc-shaped member and the scraping tool. 1... Container body, 3a, 3b... Rotating shaft, 5a, 5
b... Disc-shaped member, 7a, 7b... Stirring blade, 10... Projection chamber, 12... Scraping tool.

Claims (1)

[Claims] 1 Two rotating shafts with disk-shaped members through which a heating or cooling medium flows are installed laterally through the end wall of the container body, and stirring blades are attached to the outer periphery of the disk-shaped members. The disc-shaped member has a conical shape with a large thickness at the part where it is attached to the rotating shaft and a small thickness at the part where the stirring blade is attached, and a conical member that extends in the axial direction of the container body at the top of the container body. A protrusion chamber is provided in communication with the container body so that both side walls of the protrusion chamber are at the center of the rotation axis or inside the rotation axis, and the bottom and sides of the container body correspond to the trajectory of the tip of the stirring blade. A stirring device for powder and granular material, characterized in that it is composed of a partial cylinder along the .