JPS5844014B2 - Granulation equipment - Google Patents

Description

[Detailed description of the invention] The present invention relates to a granulation device.

That is, it is an object of the present invention to provide an apparatus for granulating a liquid raw material into a granular solid.

The following methods have been conventionally used industrially as granulating devices.

1) Rothsier-Banka method 11) Dripping method into refrigerant material 111) Rotary kiln power method IV) High tower dropping blade method■) High tower injection power method vD Fluidized bed method Molding from the granulation equipment of the above various methods An appropriate method is selected in consideration of the properties of the material to be granulated, specific gravity, viscosity, humidity, temperature, throughput, required granular product properties, etc.

For example, the processing amount is relatively small and the product has large particles, so it is necessary (
Accordingly, in the drug manufacturing industry or chemical fertilizer manufacturing industry, which forms different component layers within particles, (1) the Rossier-Banca method is most often adopted.

In addition, in the fertilizer industry where extremely large quantities and relatively small particles are required as a product, ii (iii) rotary force type, (i
Either v) high tower dropping method or (■) high tower injection force method is adopted.

However, recently there has been a need for a method for granulating large amounts of raw materials into large particles.

For this reason, research is being carried out on the industrialization of VD fluidized bed force type granulation equipment.

Originally, the characteristics of the fluidized bed force type are: 1) The temperature of the entire fluidized bed is uniform because the thermal conductivity due to gas-liquid contact is low.

(2) The pressure loss in the fluidized bed is constant as shown in Figure 2.

It is easy to control the residence time of 0 particles in the fluidized bed, and (2) operation is easy if appropriate conditions are set, and 0 particles are easy to handle.

In addition, compared to the usual granulation method, the construction cost of the fluidized bed method (generally speaking, the equipment is 20 to 30% cheaper).

However, although the granulation process using only a fluidized bed is extremely effective for the granulation itself (of course, its characteristics such as drying, cooling, and classification), it has the following drawbacks in actual operation.

(1) It is necessary to separately prepare small particles to serve as granulation nuclei in advance and constantly replenish them in an appropriate amount.

Since these granulation nuclei are usually small particles, a large amount escapes due to the rising air current within the fluidized bed during replenishment, reducing operational efficiency.

(11) It is difficult to replenish core particles for granulation and uniformly disperse them on the surface or inside the fluidized bed.

Non-uniform replenishment makes the flow resistance within the fluidized bed non-uniform, leading to an in-plane phenomenon of upward air currents, and the surface of the fluidized bed gradually begins to slope sharply until the fluid movement stops.

Once such a phenomenon occurs, it is impossible to restore the normal state.

G11) Replenishment of the liquid material to be granulated becomes uneven.

Normally, the liquid material to be granulated is injected into the fluidized bed (using a radiator), but small particles around the radiator become hard to stick to each other and gradually form lumps in some areas. At the same time, local humidity differences occur, further promoting the clumping phenomenon.

These drawbacks make it difficult to operate stably for a long time in the case of large industrial equipment even if the operating conditions are carefully set to 1J%.

These are disadvantages that cannot be avoided as a granulation device using only a fluidized bed.

It is also well known that the spouted bed method has already been industrialized as a fertilizer granulation device.

That is, (1) the contact time between the liquid material to be granulated and the high-speed upward airflow is extremely short;

Usually it is about 0.5 to 1.0 seconds. ■As shown in Figure 2, the pressure loss inside the device is small.

■The heat transfer efficiency between the liquid material being granulated and the high-speed rising air is extremely high.

(2) When the liquid substance to be granulated is injected into a high-speed upward air current, it is very easily divided into small droplets and solidified to form granulation nuclei.

(2) The liquid substance to be granulated adheres to the granulation nuclei in a high-speed upward airflow that is accompanied by the granulation nuclei in advance, and the small granulation nuclei gradually grow into large particles.

It has such characteristics.

However, the granulation method using only a spouted bed has the following drawbacks.

That is, (1) the contact time between the liquid material to be granulated and the high-speed upward air current is extremely short, so that the generated particles cannot be cooled.

(11) Solidified particles are non-uniform and particle classification cannot be performed as in a fluidized bed.

0I [) There is no residence time to effect drying of the solidified particles.

The above are the advantages and disadvantages of each of the fluidized bed and the spouted bed, but both have different characteristics regarding granulation of liquid substances.

This invention effectively combines the characteristics of a spouted bed and a fluidized bed, each set under two different state conditions.
The liquid material to be granulated is injected and divided into fine droplets by the rising air current formed on the outer periphery to form granulation nuclei, and the droplets of the liquid material are prevented from adhering to the small particles that are classified and circulated in the fluidized bed. The present invention relates to a granulation device capable of efficiently milling and crushing a wide range of granular substances with large particle sizes in large quantities for various substances characterized by growing them into large-diameter particles.

In this invention, in the center of the bottom of the tower, there is provided a mechanism for injecting the liquid material to be granulated in the direction of the upper blade, and a group of airflow holes arranged in a horizontal ring shape around the mechanism to form an accelerated ascending airflow ring. a vertical cylindrical spouted bed inner cylinder, a perforated plate provided at the bottom for introducing accelerated gas upward, and a circulation path through which part of the particulate matter on the perforated plate flows into the spouted bed inner cylinder. A fluidized bed outer cylinder having a particulate matter discharge passage and defining a horizontal cross-sectional annular space surrounding the outer periphery of the spouted bed inner cylinder, a supply path for liquid material to the injection mechanism, and an air flow in the spouted bed inner cylinder. gas supply path to the hole group;
A gas supply path below the perforated plate of the fluidized bed outer cylinder, an upper sealed cavity in the fluidized bed outer cylinder in which the upper edge opening of the spouted bed inner cylinder is located in the center, and a gas supply path from the upper sealed cavity. This is a granulation device characterized by comprising a gas flow discharge path.

In this invention, a fluidized bed and a spouted bed are made to exist separately inside the device as shown in Fig. 3, and each performs a granulation action and is controlled at different conditions such as temperature, wind pressure, and air volume according to the required function. This device is configured so that conditions are set and granulated particles are continuously circulated between both layers.

In other words, the spouted bed section of the inner tube generates granulation nuclei and enlarges the small particles, and the particles that naturally fall and solidify in the fluidized bed section of the outer tube are dried, cooled, and classified, and the large particles are removed from the device. This granulation device is configured so that the small particles discharged from the granulator are circulated to the spouted bed section.

The overall configuration diagram of the embodiment shown in FIG. 3 will be described below.

The outer cylinder 1 is a cylindrical body with a circular horizontal cross section, and is equipped with an exhaust port 12 and a solid separator at the top lid of the tower, and two or more discharge ports 1 at the bottom of the tower.
It has 3.

The inner cylinder 2 is a partition wall for forming a spouted bed therein, and a nozzle 5 for injecting a liquid material to be granulated as shown in FIG. 5 is provided at the bottom of the cylindrical body formed by the inner cylinder 2. It is provided.

As shown in FIG. 4, either a fixed type or a rotating type of injection nozzle is selected depending on the properties of the material to be granulated.

Generally, the one-rotation type is selected for the injection of highly viscous substances,
This is rotated at a speed of over 300 revolutions per minute.

For low viscosity substances, use 307 for liquid substances that are ejected in a fixed manner.
Pressurize to below n1rL water column and inject.

In addition, although a large number of jets fL are provided on the surface of a fixed nozzle, a hole diameter of 0.4% to 01.5% is suitable.

The outer circumferential hole 7a of the injection nozzle forms an accelerated high-speed upward airflow wall of gas that is chemically inert to air, nitrogen gas, and other crushed substances, and the small particles circulated through the communication path 6a and the nozzle 5. By blowing up the injected liquid substance, the fine droplets of liquid substance adhere to the circulated small particles and grow into large particles, and the remaining liquid substance gets caught up in the annular air flow wall and is divided, becoming particle nuclei and mixing the two. The particles then reach the column top space 11, where they are separated by the air flow and fall naturally, reaching the fluidized bed section 3 inside the outer cylinder 1.

The fluidized bed section 3ij is maintained in a fluidized state by the gas flow blown from the dispersion plate 4, and the particles are dried, cooled and classified,
The amount of granules taken out from the discharge port 13 is adjusted to allow the granules to remain there for a period of time necessary to meet the required granulation conditions.

Large particles are discharged from the discharge port 13 due to the classification action.

The small particles circulated in the spouted bed section reach the bottom of the spouted bed section from the partition wall 6 through the communication path 6a, and grow into large particles in the spouted bed section.

In the spouted bed section, a wind speed necessary to blow up the small particles circulated through the communication path 6a and the liquid material injected from the nozzle 5 is required, but the necessary conditions are the specific gravity viscosity shape of the material to be granulated and the product particles. Although it varies depending on the nature of the
A wind speed of 30 m/sec to 30 m/sec is chosen.

When this wind speed is excessively high, the liquid material is prevented from blowing out and solidifies into a lump.

The fluidized bed in the outer cylinder 3 is maintained in a fluidized state by being blown into the fluidized bed from the dispersion plate 4 through the conduit 9 after the gas is dried and heated or cooled.

The apparatus of this invention is particularly effective for granulation in cases where the quality is likely to change due to heating, since the high temperature part is limited to the spouted bed part.

Further, by selecting either a fixed type or a rotating type as the injection mechanism for the liquid material to be granulated depending on the viscosity and temperature of the material, it is possible to handle a wide variety of materials.

[Brief explanation of the drawing]

FIG. 1 is a schematic diagram showing changes in the powder layer due to wind speed. FIG. 2 is a diagram showing changes in particle layer pressure loss depending on wind speed. FIG. 3 shows an embodiment of the overall assembly diagram of the device. FIG. 4 shows an embodiment of a nozzle for spraying the liquid to be granulated, which is provided at the bottom of the spouted bed section. FIG. 5 is a diagram of the injection part and the small particle circulation mechanism at the bottom of the jet main part.

Claims (1)

[Claims] 1 Inside a vertical cylindrical spouted bed equipped with an injection mechanism for the liquid material to be granulated at the center of the tower bottom and a group of airflow holes arranged in a horizontal ring to form an accelerated ascending air ring around the injection mechanism. The cylinder has a perforated plate provided at the bottom for sending accelerated gas upward, a circulation path through which part of the granules on the perforated plate flows into the spouted bed inner cylinder, and a particulate material discharge path. a fluidized bed outer cylinder forming a horizontal cross-sectional annular space surrounding the outer periphery of the spouted bed inner cylinder, a supply path for liquid material to the injection mechanism, a gas supply path to the airflow hole group of the spouted bed inner cylinder; From the gas supply path below the perforated plate of the fluidized bed outer cylinder, the upper sealed cavity in the fluidized bed outer cylinder in which the upper edge opening of the spouted bed inner cylinder is located in the center, and the upper sealed cavity. A granulation position characterized in that it consists of a gas flow outlet.