JPS6332497B2 - - Google Patents

Description

[Detailed description of the invention] This invention relates to a spouted bed granulator.

In recent years, this type of granulator has become widely used, but the technically important point in this type of granulator is how well it can form a spouted bed.
On the other hand, looking at the overflow discharge state of the product with the conventional device, the overflow port (discharge port) in the conventional device was a small part of the top of the device, so large particles that had reached the desired particle size were discharged. There are few opportunities to do so, and it is easy to produce ultra-large particles, and when ultra-large particles are generated, it is difficult to continue operation any longer. A circumferential extraction method can be considered. However, when we experimented with this all-round extraction method, we found that if the jet air velocity (air volume) was increased, the proportion of small particles smaller than the desired particle size would be scattered and flowed out. The amount is reduced and the throughput of the device is reduced. Furthermore, if the air flow rate is increased to an extreme extent, the particles remaining in the conical portion will disappear, making it impossible to form a spouted bed with good density. Conversely, if the air volume is small, the throughput of the apparatus will be small and the granulation efficiency will be reduced in this case as well. Therefore, 1 in Figure 1
Adjustment of the wind speed at the lower end portion of b is extremely delicate, and the optimum operating range becomes extremely narrow. In addition to the inherent difficulties of this all-round extraction method, in spouted bed granulation, it is generally impossible to form a good spouted bed if the flow rectification conditions at the bottom of the granulator are poor; Formation of a spouted bed at the start of operation required a high degree of skill and was accompanied by many difficulties.

This invention was developed to eliminate the above-mentioned drawbacks, and its purpose is to form a good spouted bed, increase the throughput of the granulator, and improve the granulation performance.

The present invention will be explained below with reference to an embodiment shown in FIG. 1 is a granulator, and its cylindrical part 1
A conical portion 1b of an inverted truncated cone-shaped container is formed at the bottom of a. The cylindrical portion 1a and the conical portion 1b are spaced apart from each other, so that an overflow port 2 is formed on the entire periphery of the upper opening of the conical portion 1b. An air jet pipe (hereinafter referred to as jet air feed pipe or simply air feed pipe) 3 communicates with the lower part of the conical portion 1b. Further, an injection nozzle 4a of the melt supply pipe 4 is provided upward in the constricted portion at the lower part of the conical portion 1b. Reference numeral 5 designates a circulating particle inlet for supplying seed particles to be enlarged or particles that have not reached the desired particle size to the granulator again, and is used to feed seed particles to the lower part of the cylindrical portion 1a, that is, the guide tube 10, above the conical portion 1b. It is equipped for. The lower part of the cylindrical part 1a and the outer periphery of the conical part 1b are covered by a guide chute 6, the lower part of which serves as a product particle outlet 7. 3 is an air outlet.

On the other hand, a stainless steel rectifier tube 9 whose diameter is smaller than the diameter of the upper opening of the conical part 1b is provided at the upper center of the conical part 1b.
The lower end surface of the rectifying tube body 9 is spaced apart from the wall surface of the conical portion 1b, and its peripheral wall surface is also spaced apart from the wall surface of the conical portion 1b, and an appropriate number of support rods (Fig. (not shown). It is also possible to suspend and support from 1a using a suitable support rod.

Further, at the upper end of the conical part 1, a guide cylinder 10 is provided at a distance from the upper end, and the diameter of the lower end thereof is approximately the same as the diameter of the upper end opening of the conical part 1b.
It is provided so as to face b.

In the device configured in this way, the conical portion 1b
The small powder particles supplied from 5 are blown up and fluidized by the jet air sent through the air supply pipe 3, and the molten liquid injected from the nozzle 4a becomes the small powder particles. It is applied to the surface of the granules and solidified or dried to form granules. The jet particles mainly pass through the inside of the rectifying tube body 9 and rise almost along the central axis to the upper part of the cylindrical portion 1a, and then fall along the peripheral wall of the cylindrical portion 1a and are guided to the guide tube 10, Granulation is carried out in a state in which the particles pass through the outside of the rectifier tube 9 and return to the spouted bed of the conical portion 1b, as indicated by the downward arrow in FIG.

In the part of the spout layer of the conical part 1b that is outside the rectifier tube 9, a part of the jet particles that have returned from above overflow from the overflow port 2, and the remaining particles flow into the rectifier tube 9.
and the conical portion 1b, and is again blown up from the inside of the rectifier tube 9.

According to this invention, if the rectifier tube body 9 is specially provided, the amount of air fed through the air feed tube 3 can be significantly increased. For example, the lower end of 1b is approximately 30m/
Even at high wind speeds of sec, small particles do not scatter and flow out from the overflow port 2. The cause is the rectifier tube 9
As a result, the thrust force that blows up the particles
This is because the particles are concentrated in the central part of the conical part 1b and do not cover the entire particle layer in the peripheral part of the conical part 1b. The rectifier tube 9 maintains the spouted bed, protects the scattering of small particles and the descent of particles in the particle bed.

In this way, even if the air volume is increased, small-diameter particles will not flow out, making it possible to increase the throughput of the granulator, improving the granulation capacity, and stabilizing the amount of particles retained in the conical portion 1b. However, the operating load range is also wide. Further, since the overflow of particles is caused by extraction from the entire circumference, generation of ultra-large particles due to the conventional partial extraction method can be reliably prevented. Furthermore, by providing the rectifier tube 9, the particles stably stay in the conical portion 1b at the start of operation, making it extremely easy to start the granulator. Further, even if the state of the air flow for forming the spouted layer into the conical portion 1b is somewhat unstable, there is also the effect that the spouted layer can be formed.

In the above example, the rectifier tube 9 with a uniform diameter is vertically provided, but it is also effective to use an upwardly expanding type or a downwardly expanding type tube. In addition, the diameter and length of the tube 9 can be changed as appropriate depending on the particles to be treated and the operating conditions, or the tube can be formed from unit tube pieces of segments and the diameter of the tube can be changed. good. Regarding the size, it is desirable that the upper end of the pipe body 9 be located at a position lower than the overflow port 2.

As described above, this invention organically combines the entire circumference extraction and the special installation of the rectifying pipe body in terms of the functionality of the granulator, increasing the throughput of the granulator and containing particles of a desired particle size. It has remarkable effects in smoothly discharging particles at a low rate, maintaining good formation of a spouted bed, and improving controllability of operating conditions.

[Brief explanation of the drawing]

FIG. 1 is a schematic vertical cross-sectional view showing an embodiment of the granulator of the present invention. 1... Granulator, 1a... Cylindrical part, 1b... Conical part,
2... Overflow port, 3... Air feed pipe, 4a... Injection nozzle, 9... Rectifier tube body, 10... Guide tube.

Claims (1)

[Scope of Claims] 1. Particles containing product particles overflow from the entire periphery of the upper end opening of the cone-shaped part of the inverted truncated cone-shaped container whose lower end communicates with the air ejection pipe, A vertical rectifier tube is provided at the upper center of the section to surround the spouted flow layer, and the diameter of the lower end is equal to the diameter of the upper end opening of the conical section. A guide cylinder is provided which is substantially the same as the
A spouted bed granulator characterized in that the lower end surface of the rectifier tube is spaced apart from the wall surface of the conical portion. 2. The spouted bed granulator according to claim 1, wherein the upper end surface of the rectifier tube is located higher than the periphery of the upper end opening of the conical portion.