WO2001036107A1

WO2001036107A1 - Particle coating device, throttle plate for jet tower and particle coating method

Info

Publication number: WO2001036107A1
Application number: PCT/JP1999/006389
Authority: WO
Inventors: Tadao Sato; Susumu Tamura; Shigeo Fujii; Takehiko Takahashi
Original assignee: Chisso Corporation
Priority date: 1999-11-16
Filing date: 1999-11-16
Publication date: 2001-05-25

Abstract

A particle coating device provided with a jet tower (2), wherein a throttling plate (52) having a plurality of air flow holes (56) drilled therein and coating liquid atomizing nozzles (26) adjacent to the throttling plate (52) are mounted to a jet gas inlet (10) of the jet tower (2), the air flow holes having a total opening area which is 10 to 70% of the inner section area of the inlet. A throttling plate (52) having a plurality of air flow holes (56) drilled therein having a total opening area which is 10 to 70% of the inner section area of the jet gas inlet (10) of the jet tower (2). The particle coating device, wherein particles are supplied to the jet tower (2) having guide pipes (6) thereinside, a heated jet gas is jetted into the jet tower (2) through air flow holes (56) in the throttle plate (52) to form a particle jet layer, a coating liquid is atomized into an atomized flow through coating liquid atomizing nozzles (26), and a coating liquid solvent deposited on the surfaces of particles in a jet condition is evaporated to form coating material coats on the particles.

Description

Specification

Granule coating apparatus, throttle plate for jet tower, and granule coating method

Field of the invention

The present invention relates to a particle coating apparatus, and more particularly, to a spouted bed type particle coating apparatus and a throttle plate for a spout tower attached to the apparatus. Further, the present invention relates to a granule coating method using the granule coating apparatus.

Technology background

Spouted bed technology is one of the solid-gas contact technologies. Fluidized bed technology deals with solid-gas reactions, heat exchange, drying of granules, and granules that are relatively coarser than the granules. It is used for coating, granulation, etc. The spouted bed apparatus used in this technology is equipped with a spout tower consisting of a vertical cylindrical body having an inverted conical bottom, a granule supply device and a spouted gas supply device. The high-speed jet gas is injected vertically upward into the jet tower through the orifice provided at the lower end of the tower, and the particles flowing inside the tower move upward at the center of the tower and downward at the periphery of the tower. That is, a spouted bed is created to bring solids and gas into contact (Chemical Engineers' Handbook, Fourth Edition, John H. Perry, 20-41).

The granule coating method based on this spouted bed technology sprays a coating liquid into a spouted bed and evaporates the solvent of the coating liquid adhering to the surface of the particles in a spouted state, thereby forming a coating film on the surface of the particle. This method is mainly used for coating small-scale granules for pharmaceuticals and other products.

In recent years, granular fertilizers such as urea have been coated with a water-soluble resin, etc., for a certain period of time during which no active components eluted or were extremely suppressed after fertilization (this period is referred to as the “initial elution period”) The time-eluting type coated granular fertilizer having a desired elution pattern of the active ingredient is disclosed in Japanese Patent Application Laid-Open No. It is proposed in Japanese Patent Application Laid-Open No. 6-87664.

When spouted bed technology is used to cover a large amount of granular material for fertilizers and the like as described above, it is necessary to use a spout tower with a large cross-sectional area. Generally, when the cross-sectional area of a spout tower is large, a fluidized bed is formed over the entire cross section of the tower, or a jet gas is drifted and it is difficult to form a normal spouted bed. Therefore, it is difficult to adopt spouted bed technology for processing large quantities of granular material. In Japanese Patent Publication No. 2_3 1 9 39, a throttle plate with one vent hole, that is, an orifice plate, is attached to the jet gas inlet of the jet tower, and a guide pipe is installed vertically above the throttle plate. Using a coating device including a spouted jet tower, inert jet gas is injected into the spout tower, the flow velocity passing through the orifice is 20 m / sec to 70 m / sec, and the flow velocity in the guide pipe is 20 m / sec. There is disclosed a method for coating a large amount of granules, introduced by adjusting the flow rate to less than sec.

This method is used to coat particles of relatively high melting point that can use high-temperature jet gas, such as rice granular ammonium sulfate, with an olefin resin. A large amount of solvent used can be evaporated and the coated granules can be dried in a short time, so it is possible to spray and supply a relatively high concentration of the coating resin solution with a relatively high melting point. This method has good production efficiency and is highly economical as a method for coating a large amount of granules.

On the other hand, in the above method, when relatively low-melting particles, for example, granular urea, are coated with a coating material using a high-temperature jet gas having a melting point or higher than the melting point of the particles, the outer annular portion of the guide tube is formed. Particulate sedimentary layer (fixed layer) is easily melted and solidified. Also, since particles are easily melted and solidified into the orifice at the bottom of the inverted cone, uneven solvent evaporation in the jet tower As a result, the circulation of the granules becomes uneven and it becomes difficult to maintain stable operation. In such a case, the temperature of the jet gas must be kept below the melting point of the granules. Cannot be used to increase production efficiency.

In addition, when the amount of jet gas that is maintained at a temperature below the melting point of the granules is increased to evaporate a large amount of solvent and dry a large amount of granules, the gas is sent to the guide tube from the bottom of the spout tower. The fluctuations in the amount of particles produced, so-called pulsation phenomena, cause unstable operation. If pulsation occurs, the coated film of the particles will be damaged. When the coated granules obtained are time-dissolved fertilizers, the amount of active ingredient eluted during the initial dissolution period increases, and a desired dissolution pattern cannot be obtained.

Therefore, it is extremely difficult to use a conventional spouted bed type coating device to coat a large amount of granular active ingredient with a resin so as to have a desired elution pattern. Met.

An object of the present invention is to provide a spouted bed type particle coating apparatus suitable for coating a large amount of particles with high efficiency, particularly suitable for mass-producing a time-dissolved fertilizer. Another object of the present invention is to provide a throttle plate mounted on a jet tower having a relatively large cross-sectional area.

Another object of the present invention is to provide a method for coating a granular material using the above-described granular material coating apparatus.

Summary of the Invention

The present inventors mounted a throttle plate having a plurality of vent holes at the jet gas inlet of a jet tower provided with a guide tube, and caused the particles to be present in the jet tower to jet the jet gas through the vent holes. As a result of the introduction into the tower, it was found that fusion and pulsation of the granules were prevented, and a good spouted bed was formed.

The present invention comprises a jet tower consisting essentially of a vertical body and an inverted cone-shaped bottom, a granular material supply device, a jet gas supply device and a coating liquid supply device, and the jet gas at the lower end of the inverted cone-shaped bottom of the jet tower. Throttle plate with a total opening area of 10 to 70% of the inner cross-sectional area of the jet gas inlet with multiple vent holes perforated at the inlet, and a throttle plate Is a granule coating apparatus equipped with a coating liquid spray nozzle in close proximity to the apparatus.

In another aspect of the present invention, a plurality of vents are formed of a single plate perforated in a region defined by an inner cross section of a jet gas inlet of a jet tower, and the total opening area of the vents is equal to the jet gas inlet. This is a throttle plate for a jet tower having an inner cross-sectional area of 10 to 70%.

Still another aspect of the present invention is a method for supplying granules from a granule supply device to a jet tower of the granule coating device, and heating the jet gas heated from the jet gas supply device through a vent hole of a throttle plate into the jet tower. A spouted layer of the sprayed particles is formed, and the coating liquid is sprayed from the coating liquid supply device into the spouted layer formed through the coating liquid spray nozzle, and the coating liquid adhering to the surface of the granules in the jet state is removed. This is a granular coating method in which a solvent is evaporated to form a coating film of the coating material on the granular surface.

BRIEF DESCRIPTION OF THE FIGURES

FIG. 1 is a flow sheet showing one embodiment of the granule coating apparatus of the present invention. FIG. 2 is a plan view showing one embodiment of a throttle plate for a jet tower of the present invention.

FIG. 3 is a plan view showing another embodiment of the throttle plate for a jet tower of the present invention.

FIG. 4 is a plan view showing a conventional throttle plate for a jet tower.

Detailed description of the invention

As shown in FIG. 1, the granule coating device of the present invention comprises a jet tower 2, which is essentially composed of a vertical body 4 and an inverted conical lower portion 8, a granule supply device, a jet gas heater 20, and a blower. It comprises a jet gas supply device consisting essentially of 22 and a coating solution supply device consisting essentially of a coating solution preparation tank 32 and a coating solution pump 28.

The jet tower 2 has a top plate 42 provided with a jet gas exhaust pipe 40 and a vertical body 4 provided with a granular material inlet 36, and is connected to the vertical body 4 and has a gradually decreasing cross-sectional area as it goes downward. The inverted cone bottom 8 and inverted cone bottom 8 It further comprises a guide pipe 6 which is constituted by a jet gas inlet 10 located at the narrowed lower end and which is preferably provided coaxially and vertically inside the vertical body 4.

The horizontal cross-sectional shape of the vertical body 4 is not particularly limited, and may be either circular or polygonal. However, it is preferable that the shape be circular in terms of uniformity of particle circulation in the vertical body 4. .

The narrowing angle of the inverted conical bottom 8 with respect to the central axis of the jet tower is set at the repose angle r of the granules in order to smoothly supply the granules from the descending region to the ascending region and discharge the product coated granules. Is preferably smaller than (90−; r.) X 2. The guide pipe 6 is fixed or suspended coaxially with the vertical body 4 above the jet gas inlet 10 in the vertical body 4, and separates a rising area and a falling area of the granular material in the jet tower. . The guide pipe 6 is a cylindrical body having a cross-sectional area of 0.5 to 4 times, preferably 0.8 to 3 times the inner cross-sectional area of the jet gas inlet 10. The guide pipe 6 generally has a cross-sectional shape similar to that of the vertical body 4, and when the vertical body 4 is cylindrical, the guide pipe 6 is formed of a cylindrical body such as a pipe. The guide tube usually has a smooth surface, but may be formed of a tubular body having small holes, a tubular body formed of a wire mesh, or the like. Preferably, in order to minimize damage to the coating film at the time of coating the granules, a smooth pipe without holes or protrusions or a pipe lined with a fluororesin or the like on the inner surface is used as the guide pipe 6. Is done.

The jet gas inlet 10 is equipped with a throttle plate 52 having a plurality of vent holes as shown in Figs. 2 and 3, and a coating liquid spray nozzle 26 near the throttle plate 52. Is arranged. The jet gas inlet 10 may be provided with a conventional orifice plate 84 or a venturi nozzle as shown in FIG. 4 instead of the throttle plate 52 if necessary.

The preferred jet tower 2 has a cylindrical vertical body 4, an inverted conical lower part 8 and a cylindrical It has a guide tube 6 of a shape.

As shown in FIGS. 2 and 3, the throttle plate 52 of the present invention includes a plurality of vent holes 56 and / or a plurality of vent holes 56 in an area 54 defined by the inner cross section of the jet gas inlet 10.

It consists of a smooth plate with perforated 5-8.

In the diaphragm plate 52 of the present invention, the number of air holes, the shape of the air holes and the dimensions of the air holes are such that the opening ratio defined by the following equation is 10 to 70%, preferably 20 to 70%.

Selected to be in the 60% range.

Opening ratio (%) = (total opening area of all vents / area of area 54) X 100 If the opening ratio of the vents is too small, the jet gas flow velocity at the jet gas inlet 10 becomes excessive. , on the other hand, if too large, injection-stream gas flow rate at the jet gas inlet 1 0 is too small, _c plurality of vent holes can not be achieved the function as the diaphragm plate, the jet gas uniformly from the vent holes The jet gas can be jetted into the jet tower 2, and it is sufficient that the jet gas is arranged in the jet tower 2, preferably in the guide tube 6, so that the upward flow of the jet gas is not deflected. There are no particular restrictions. Preferably, a plurality of vents having substantially the same opening area are uniformly arranged in a region 54 defined by the jet gas inlet of the throttle plate, or are defined by the jet gas inlet of the throttle plate. Main vents are arranged at the center of the region 54, and a predetermined number of sub vents are arranged at substantially equal intervals outside the outer edge of the main vent. When the jet tower 2 has the cylindrical body 4, usually, 3 to 20 pieces, preferably 3 to 12 pieces of circular shapes having a diameter calculated from a predetermined opening ratio are formed in the circular area 54. Vent holes are located and perforated. If the number of vent holes is less than three, the flow of gas passing through the jet gas inlet 10 becomes uneven, and particles are easily deposited and solidified on the throttle plate 52. On the other hand, if the number of air holes exceeds 20, the effect proportional to the increase in the number of air holes cannot be obtained, and the production of the diaphragm plate becomes complicated.

For example, in the diaphragm plate 52 of the embodiment shown in FIG. A plurality of circular ventilation holes 56 (four in this figure) having substantially the same diameter are arranged at equal intervals on a concentric circle with respect to the center. In the diaphragm plate 52 of the embodiment shown in FIG. A relatively large-diameter circular main vent hole 5 6 is provided at the center of the main vent hole 56, and a plurality of circular sub-vent holes 5 8 (which have a smaller diameter than the main vent hole 56 on a concentric circle outside the main vent hole 56). In this figure, eight are drilled at equal intervals. The number of the secondary vents is not particularly limited, but is preferably 6 to 12. Examples of the arrangement of the ventilation holes include a grid pattern, a staggered pattern, and the like in addition to the above examples.

In the diaphragm plate 52 of the embodiment shown in FIG. 3, the ratio of the total opening area of the sub-vents to the opening area of the main vents is preferably 100: 10 to 70. If the ratio of the opening area of the sub vent to the opening area of the main vent is too small, the particles tend to deposit and solidify on the aperture plate 52. If the ratio is large, it will be difficult to obtain a sufficient flow velocity of the jet gas.

The outer shape of the throttle plate is not particularly limited, and is appropriately selected depending on a method of attaching the throttle plate to the jet gas inlet 10. Either a fixed type or a movable type may be adopted as a method of attaching to the jet gas inlet 10, but a movable type is preferable in consideration of discharge of product-coated granules. For example, a slide type as shown in FIG. 2 and a rotary type as shown in FIG. 3 are preferable.

One end of a pipe 12 is connected to the jet gas inlet 10 equipped with the throttle plate 52, and a coated particle discharge port 16 is provided at the other end of the pipe 12 via an on-off valve 14. One end of a jet gas supply pipe 18 is connected to the pipe 12, and the other end of the jet gas supply pipe 18 is connected to a blower 22 via a jet gas heater 20 and a flow meter 24 in the middle. Are linked. The jet gas from the blower 22 is heated by the jet gas heater 20 and then jetted into the jet tower 2 through the ventilation holes of the throttle plate 52 attached to the jet gas inlet 10. The coating liquid spray nozzle 26 is provided with a jet gas inlet 10 in a vertically extended area of the vent hole so that the coating liquid can be uniformly sprayed into the jet gas passing through the vent hole of the throttle plate 52. Are arranged along the central axis of

The coating liquid spray nozzles 26 may be arranged in a plurality of air holes as shown in FIG. 2 or in one air hole as shown in FIG. 3, and the number is not particularly limited.

The mounting height of the coating liquid spray nozzle 26 may be higher or lower than the jet gas inlet 10. The position and shape of the spray nozzle 26 are appropriately determined according to the properties of the spray liquid, operating conditions, and the like.

One end of a coating liquid supply pipe 30 is connected to the spray nozzle 26 via a coating liquid supply pump 28, and the other end of the coating liquid supply pipe 30 is a coating liquid preparation tank with a heating jacket 34. 3 Connected to 2. The coating liquid prepared in the coating liquid preparation tank 32 is sprayed from the spray nozzle 26 into the jet gas by the coating liquid supply pump 28 through the coating liquid supply pipe 30.

In the granule coating method of the present invention, the granules 39, 44, and 46 are provided on the vertical body 4 of the jet tower 2 via a granule charging valve 38 using the above-described granule coating apparatus. The granular material is supplied into the spout tower 2 from the inlet 36, and the spout gas is spouted from the spout gas inlet 10 through the vent holes 56 and 58 of the throttle plate 52 to form a spouted layer 37. Then, the coating liquid is sprayed from a spray nozzle 26 into the spouted bed, and the solvent of the coating liquid attached to the surface of the particles in a jet state is volatilized and evaporated to form a coating film of the coating material on the particles. It is.

In the coating method of the present invention, the spouted layer 37 has a flow velocity of the jet gas passing through the ventilation hole of the throttle plate 52 of 20 to 7 OmZsec, although it varies depending on the type, density, particle size, etc. of the granules. When the guide pipe 6 is provided, the superficial velocity of the jet gas in the guide pipe 6 is reduced By setting the terminal velocity to 1.5 to 3 times the terminal velocity of 39, a better spouted bed 37 is formed.

The granules to be coated are not particularly limited, but are particularly effective in the case of granules in which it is necessary to control the elution rate of the active ingredient contained in the granules by coating. The active ingredient varies depending on the purpose of use, for example, urea, ammonium sulfate, salt and salt, ammonium nitrate, potassium chloride, sulfate potassium, nitrate potassium, sodium nitrate, ammonium phosphate, potassium phosphate, lime phosphate, chelate iron, iron oxide, chloride Iron, boric acid, borax, manganese sulfate, manganese chloride, zinc sulfate, copper sulfate, sodium molybdate, ammonium molybdate, OMUP (crotilidene diurea), IBDU (isobutylidene diurea), oxamide, etc. And pesticides such as fertilizers, insecticides, fungicides, and herbicides. The granules may be granules of one or more active ingredients, or granules comprising one or more of the active ingredients and an inert carrier such as bentonite, zeolite, talc, cres, diatomaceous earth and the like. There may be. Further, the above-mentioned active ingredient particles may be coated with a resin or an inorganic substance. The particle size of these granules is usually in the range of 0.1 to 10 bandages, preferably:! Range of ~ 5 mm.

The jet gas only needs to be inert to the granules and the coating liquid, for example, air, nitrogen gas, helium gas, etc., and the organic solvent in the coating liquid was partially removed from the jet tower outlet gas. Recycled gas can be used.The coating material used to coat the granules is not particularly limited, but when producing time-eluting coated granules, the elution of the active ingredient contained in the granules should be performed. Materials and compositions with strict control can be selected. As such coating materials. Inorganic coating materials represented by sulfur, thermosetting resins such as alkyd resins, phenolic resins, epoxy resins, etc .; thermoplastic resins such as polyolefins such as polyethylene and polypropylene; and polyvinylidene chlorides. Is mentioned. Of these, when coating granules containing active ingredients that require strict and long-term dissolution control such as fertilizers and pesticides, use thermosetting resin or thermoplastic resin as the coating material. If more advanced elution control is required, it is particularly preferable to use a thermoplastic resin.

Preferred thermoplastic resins include polyolefin and its copolymer, polyvinylidene chloride and its copolymer. Preferred polyolefins and their copolymers are polyethylene, polypropylene, ethylene-propylene copolymer, ethylene / vinyl acetate copolymer, ethylene / carbon monoxide copolymer, ethylene / vinyl acetate / carbon monoxide copolymer And ethylene Z acrylate copolymer, ethylene nomethacrylic acid copolymer, rubber resin, polystyrene, polymethyl methacrylate, and the like. Preferred examples of polyvinylidene chloride and its copolymer include polyvinylidene chloride and a vinylidene chloride / vinyl chloride copolymer. Furthermore, biodegradable polyesters represented by poly-2-hydroxy xy-2-alkylacetic acid, poly-1-hydroxy-3-alkylpyrionic acid and the like can also be mentioned.

These coating materials can be coated on the granules by spraying them in a solution dissolved in an organic solvent or in a molten state into a spouted bed. Preferably, a film of the coating material is formed on the surface of the granular material by using a poor solvent solution of the above resin, spraying the solution into the spouted bed and instantaneously evaporating the solvent. When the solvent is flash-evaporated using a poor solvent solution of the above resin, a combination of a resin and an organic solvent that has a property of dissolving at a high concentration when heated and having a property of precipitating and gelling when cooled when cooled is used. preferable. This combination forms a very dense coating film, and is particularly suitable for forming a time-dissolved coating film.

Other coating materials include inorganic fillers such as talc, Activators and the like can also be used. These coating materials are dissolved / dispersed or melted / dispersed in a solvent and sent to a spray nozzle to be used for coating the particles.

The granule coating apparatus of the present invention can be used as it is as a granulation apparatus.

Example

The present invention will be described in more detail with reference to Examples and Comparative Examples.

1. Coating equipment

Fig. 1 shows the granule coating apparatus used in the examples and comparative examples, Fig. 2 and Fig. 3 show the diaphragm plates 52 used in Examples 1 and 2, and Fig. 8 shows the diaphragm plates 84 used in the comparative example. See Figure 4.

The used jet tower 2 had a vertical body 4 with an inner diameter of 600, a jet gas inlet 10 provided at the lower end of the inverted cone-shaped lower part with an inner diameter of 154 mm, and a total from the jet gas inlet 10 to the top plate 42. It had a height of 5,000 mm and a guide tube 6 with a diameter of 150 and a length of 880 mm inside.

In the throttle plate 52 used in Example 1, four ventilation holes 56 having an inner diameter of 45 mm are arranged at equal intervals on a circumference having a diameter of 95 referred to the center of the center of the jet gas inlet, The aperture ratio was 34% (see Figure 2). The throttle plate 52 is attached to the jet gas inlet 10 of the jet tower 2, and each of the ventilation holes is provided in Example Nos. 1-1-1 to 3-3, and two opposed ventilation holes are provided in Example Nos. 1-4. A spray nozzle 26 was placed on the center extension.

The throttle plate 52 used in Example 2 has a main ventilation hole 56 with an inner diameter of 80 at the center of the jet gas inlet, and a circle with a diameter of 95 around the center of the main ventilation hole 56. The sub-vents 58 with an inner diameter of 15 mm were arranged at equal intervals, and the opening ratio was 34% (see Fig. 3). The throttle plate 52 was attached to the jet gas inlet 10 of the jet tower 2, and the spray nozzle 26 was arranged on the extension of the center of the main ventilation hole 56. In the comparative example, an orifice plate 84 with an opening ratio of 34%, in which one vent hole 82 with an inner diameter of 95 was located at the center of the jet gas inlet, was attached to the jet gas inlet 10 of the jet tower 2. Then, the spray nozzle 26 was arranged on the extension of the center.

2. Granules

As the granules 39, 44, and 46, granular urea having an average particle diameter of 2.7, specific gravity of 1.3 g / cm ³ , and a melting point of 133 ° C was used.

3. Coating liquid

As the coating solution, a solution obtained by mixing the following at 100 ° C. was used.

Low-density polyethylene (d = 0.918, MI = 22) 9 parts by weight Flour (light flour 200 mesh pass) 1 "

Talc (average particle size 10 ni) 10 "

Toluene 230 //

4. Coating method

Using a blower 122, a predetermined amount of particles was injected from the particle input port 36 while nitrogen, which was maintained at a predetermined air volume and temperature, was blown into the jet tower 2 through the vent hole. Next, when the particles in the tower reached 70 ° C, the coating liquid supply pump 28 was operated to spray the coating liquid in the coating liquid preparation tank 32 at a predetermined speed from the spray nozzle 26 for a predetermined time. After that, the blower 122 was stopped, and the coated particles were extracted from the coated particle outlet 16.

Table 1 shows the various operating conditions, the state of the jet during operation (with or without pulsation), and the presence or absence of melting and consolidation of the granules in the jet tower.

5. Evaluation of coated granules

Covering rate of coated granules: 10 g of the coated granules were crushed in a mortar, washed with water, and only the coating material was collected. The obtained coating material was dried and calculated from the measured weight of the coating material. All samples had a coverage of 12% by weight. Initial dissolution rate: 10 g of the coated granules were immersed in 200 ml of water at 25 ° C., and the dissolution rate (%) was calculated from the amount of urea eluted in water 24 hours later.

The measurement results are shown in Table 1.

table 1

As shown in Table 1, in the embodiment equipped with a restrictor plate having a plurality of vent holes, no pulsation was observed during operation, and a good jet state was maintained. There was no melting or consolidation, and stable operation was maintained. On the other hand, in the comparative example equipped with the conventional orifice plate having one vent hole, pulsation occurred during the operation, and melting and solidification of the granules in the tower were observed.

In addition, the initial dissolution rate of the obtained coated granules was remarkably increased irrespective of the gas temperature and the air flow rate in the examples, but increased with the gas temperature and the air flow rate in the comparative examples.

The granule coating apparatus of the present invention is characterized in that the jet tower is provided with a throttle plate having a plurality of vent holes, so that the jet is prevented from drifting irrespective of the fact that the jet tower has a relatively large diameter. Are formed, and accumulation, melting and consolidation of the particles on the drawing plate are prevented. As a result, the operation of the device is stabilized, and a large amount of particles can be stably coated. In particular, more stable operation is possible with a covered device in which a guide tube is provided in the jet tower.

When a time-eluting type coated granule is produced by the method for producing coated granules using this apparatus, coated granules with stable elution can be obtained. In particular, a large amount of coated granules can be produced at a time with a stable initial elution suppression period determined by the coating composition.

Further, the method for producing coated granules of the present invention can be used as a solvent for a coating material such as polyolefin, so that it is particularly suitable for uniformly coating a polyolefin film on the surface of the granules.

Claims

The scope of the claims

1. A jet tower consisting of a vertical body and an inverted conical bottom, consisting of a granule supply device, a jet gas supply device and a coating liquid supply device, and a plurality of jet gas inlets at the lower end of the inverted cone bottom of the jet tower. A throttle plate with a total opening area of 10 to 70% of the internal cross-sectional area of the jet gas inlet, and a granule equipped with a coating liquid spray nozzle close to the throttle plate Coating equipment.

2. The granule coating apparatus according to claim 1, wherein the jet tower consists essentially of a vertical cylindrical body and an inverted conical lower part.

3. The granule coating apparatus according to claim 1, wherein the jet tower has a guide tube provided therein coaxially and vertically with the vertical body.

4. The granule coating apparatus according to claim 1, wherein a total opening area of the plurality of vents is 20 to 60% of an inner cross-sectional area of the jet gas inlet.

5. The granule coating apparatus according to claim 1, wherein the number of air holes in the aperture plate is 3 to 20.

6. The granule coating device according to claim 1, wherein the plurality of ventilation holes of the throttle plate are uniformly arranged in a region defined by the jet gas inlet.

7. A plurality of vents in the restrictor plate, the main vent is located at the center of the area defined by the jet gas inlet, and the sub vents are equidistantly arranged concentrically about the center outside the main vent. 2. The granule coating device according to claim 1, wherein

8. The granule coating apparatus according to claim 1, wherein the coating liquid spray nozzle is disposed in a vertically extending region of a part or all of the vent hole.

9. The granule coating apparatus according to claim 8, wherein the coating liquid spray nozzle is disposed in a region extending vertically from an opening region of the main ventilation hole.

10. A plurality of vents consist of a plate perforated in the area defined by the inner cross section of the jet gas inlet of the jet tower, and the total opening area of the vents is 10 to 7 of the inner cross sectional area of the jet gas inlet. Throttle plate for jet tower in the range of 0%.

11. The throttle plate for a jet tower according to claim 10, wherein the number of air holes is 3 to 20.

12. The throttle plate for a jet tower according to claim 10, wherein 3 to 12 vent holes are arranged at equal intervals on a concentric circle with respect to a center of a region defined by an inner cross section of the jet gas inlet.

13. The jet according to claim 10, wherein the main vent is located at the center of the area defined by the inner cross section of the jet gas inlet, and the sub vents are arranged equidistantly concentrically about the center outside the main vent. A diaphragm plate for a tower.

14. The throttle plate for a jet tower according to claim 13, wherein the total opening area of the sub-vents is 10 to 70% of the opening area of the main vents.

15. It consists essentially of a vertical body and an inverted conical bottom, with a guide tube inside, and 10 to 70% of the internal cross-sectional area of the jet gas inlet provided at the lower end of the inverted conical bottom. A throttling plate, in which a plurality of vent holes having a total opening area are perforated in the area defined by the inner cross section of the jet gas inlet, is attached to the jet gas inlet, and one or more coating liquid spray nozzles are provided in the vent gas inlet. The granules are supplied from the granule supply device into the jet tower arranged in the opening area, and the jet gas heated from the jet gas supply device is blown into the jet tower through the ventilation holes of the throttle plate to jet the granules. A layer is formed, and the coating liquid is sprayed from the coating liquid supply device through the coating liquid spray nozzle into the spouted bed, and the solvent of the coating liquid attached to the surface of the granules in the state of the jet is evaporated to form a layer on the particle surface A method of coating particles that forms a coating of the coating material on the surface.

16. The method for coating particles according to claim 15, wherein the flow velocity of the jet gas passing through the ventilation hole is adjusted in a range of 20 to 7 O in / sec.

17. The granule coating method according to claim 15, wherein the superficial velocity of the jet gas in the guide tube is 1.5 to 3 times the terminal velocity of the granules.