Particle processing method and processing device

Abstract

The invention provides a particle processing method and a processing device, which can supply heated seed particles to a granulation step (gr) to improve the uniformity of the temperature in a granulation device (GR), and can stably granulate particles which are uniformly dried to a desired level and have a desired particle diameter. The present invention has a particle processing method comprising: a seed particle adjustment step (sc) in which a flow layer of seed particles is formed and the seed particles in the flow layer are preheated by supplying a preheating gas to the seed particles from below via a line (16); and a granulation step (gr) in which the seed particles heated in the seed particle adjustment step (sc) are supplied via a line (1), and the surfaces of the seed particles are coated with a coating substance in a high-temperature atmosphere, thereby performing granulation. The present invention is also provided with a seed particle adjustment device (SC) and a granulation device (GR) or a seed particle adjustment and granulation device (SC / GR) for performing each of the steps.

Description

Technical Field

[0001] The present invention relates to a particle processing method and a particle processing apparatus capable of stably granulating particles that are uniformly dried to a desired level and have a desired particle size. Background Art

[0002] When manufacturing granular products (for example, chemical products, medicines, and foods), it is necessary to process solid substances into particles of a desired particle size. As a processing method suitable for mass production of granular products, for example, the following method is known: using a granulation device of a fluidized bed method or a fluidized bed / jetted bed method, the particles of the desired particle size are obtained by enlarging the seed particles (small particles composed of the above-mentioned solid substances). Specifically, a fluidized bed (or a fluidized bed and a jetted bed) of seed particles is formed by supplying gas to the seed particles from the bottom, and a solution containing a coating substance (the above-mentioned solid substance) is sprayed on the seed particles in the layer to attach the solution in a droplet shape, and the solution is dried at the same time. As a result, the surface of the seed particles is coated with the coating substance in the solution, and particles larger in size than the seed particles are obtained.

[0003] Japanese Patent Publication No. 4-63729 describes a method for processing particles using a fluidized bed / spouted bed granulator. Figure 1 The following state is described in the document: a fluidized bed space 7 (fluidized bed) for processing particles is formed by uniformly supplying fluidized bed gas (gas for forming a fluidized layer) from a bottom plate 6 that is a porous plate, and at the same time, a gas (gas for forming a spouted layer) is ejected from a supply pipe 12, and a solution containing a coating material is sprayed from a nozzle 13, thereby forming a rising and falling space 8 (spouted layer) for processing particles. Then, the droplet-shaped coating material sprayed from the nozzle 13 adheres to the surface of the processed particles (seed particles), and enlarged particles are obtained.

[0004] The particles obtained by the granulation device of the fluidized bed method or the fluidized bed / spouted bed method usually have a wide particle size distribution. Therefore, it is necessary to classify the particles into particles of product size (particles with target particle size), large particles exceeding the product size, and small particles less than the product size. Then, the particles of product size are recovered. On the other hand, large particles are crushed and reduced in size, and are supplied to the granulation device as seed particles for recycling. Small particles are directly supplied to the granulation device as seed particles for recycling. Summary of the invention

[0005] In the above-described method, it is preferred to maintain the temperature of the seed particles at an appropriate temperature that can promote drying. Therefore, in conventional general methods, for example, the gas for forming a fluidized bed (or the gas for forming a fluidized bed and the gas for forming a spouted bed) is heated, and the area where the granulation is performed by coating with the gas is maintained in an atmosphere at a temperature higher than normal temperature.

[0006] On the other hand, the particles recycled as seed particles after passing through the classification process and the like dissipate heat in the process and their temperature decreases. Therefore, the temperature of the seed particles supplied to the granulation device is usually lower than the temperature inside the granulation device.

[0007] Furthermore, the seed particles supplied to the granulating device may be exposed to the outside air before supply and absorb moisture, and the moisture content thereof may increase. In addition, the temperature may fluctuate due to the temperature difference between seasons or the temperature difference between day and night.

[0008] As described above, the temperature and moisture content of the seed particles supplied to the granulator vary due to various reasons. In addition, the inventors of the present invention have focused on the following aspects: if seed particles with low temperature or high moisture content are supplied to the granulator, the temperature in the granulator (particularly near the supply port of the seed particles) is locally reduced, and the drying becomes insufficient or uneven, so the product quality is reduced, and it is believed that it is necessary to improve it.

[0009] That is, an object of the present invention is to provide a particle processing method and a particle processing apparatus capable of stably granulating particles that are uniformly dried to a desired level and have a desired particle diameter.

[0010] Methods for solving problems

[0011] The present inventors conducted intensive research to achieve the above-mentioned purpose and found that it is very effective to add a seed particle adjustment step using a preheating gas and a fluidized bed before the granulation step and to preheat the seed particles in the seed particle adjustment step, thereby completing the present invention.

[0012] The present invention is a particle processing method, which includes a seed particle adjustment step (sc) and a granulation step (gr). In the seed particle adjustment step (sc), a preheating gas is supplied to the seed particles from the bottom to form a fluidized bed of the seed particles, and the seed particles in the fluidized bed are preheated. In the granulation step (gr), granulation is performed by coating the surface of the seed particles heated in the aforementioned seed particle adjustment step (sc) with a coating material in a high-temperature atmosphere.

[0013] In addition, the present invention is a particle processing device, which has a seed particle regulating device (SC) and a granulating device (GR). The seed particle regulating device (SC) supplies pre-heating gas to the seed particles from the bottom to form a fluidized bed of the seed particles and pre-heat the seed particles in the fluidized bed. The granulating device (GR) performs granulation by coating the surface of the seed particles heated by the aforementioned seed particle regulating device (SC) with a coating substance in a high-temperature atmosphere.

[0014] In addition, the present invention is a particle processing device, which has a seed particle conditioning and granulation device (SC / GR), the seed particle conditioning and granulation device (SC / GR) includes a seed particle conditioning zone (SCZ) and a granulation zone (GRZ), the seed particle conditioning zone (SCZ) supplies pre-heating gas to the seed particles from the bottom to form a fluidized bed of the seed particles and pre-heat the seed particles in the fluidized bed, and the granulation zone (GRZ) performs granulation by coating the surface of the seed particles heated in the aforementioned seed particle conditioning zone (SCZ) with a coating substance in a high-temperature atmosphere.

[0015] In addition, the present invention provides a method for improving an existing particle processing device, wherein the existing particle processing device has a granulating device (GR) for granulating by coating a coating substance on the surface of seed particles in a high-temperature atmosphere, and the method for improving the existing particle processing device is characterized in that:

[0016] A seed particle conditioning device (SC) is added to the above-mentioned conventional particle processing device, wherein the seed particle conditioning device (SC) forms a fluidized bed of the seed particles by supplying a pre-heating gas to the seed particles from the bottom, and pre-heats the seed particles in the fluidized bed; and, in the granulating device (GR), granulation is performed by coating the seed particles heated by the seed particle conditioning device (SC) with a coating material in a high-temperature atmosphere,

[0017] or,

[0018] The aforementioned granulation device (GR) is replaced with a seed particle conditioning and granulation device (SC / GR), which includes a seed particle conditioning zone (SCZ) and a granulation zone (GRZ), wherein the seed particle conditioning zone (SCZ) forms a fluidized bed of the seed particles by supplying pre-heating gas to the seed particles from the bottom, and pre-heats the seed particles in the fluidized bed, and the granulation zone (GRZ) performs granulation by coating the surfaces of the seed particles heated in the seed particle conditioning zone (SCZ) with a coating substance under a high-temperature atmosphere, and in the granulation zone (GRZ), granulation is performed by coating the seed particles heated in the seed particle conditioning zone (SCZ) with a coating substance under a high-temperature atmosphere.

[0019] The particle processing method of the present invention is characterized in that it has a seed particle adjustment step (sc). In the seed particle adjustment step (sc), the seed particles are preheated using a preheating gas. Therefore, the temperature of the seed particles becomes high. If the seed particles are used for granulation, it is possible to suppress the decrease in the uniformity of the temperature in the granulation device (GR), especially near the supply port of the seed particles, and the uniformity of drying.

[0020] In addition, in the seed particle adjustment step (sc), a fluidized bed of seed particles is formed by supplying a preheating gas. As a result, the seed particles in the fluidized bed are heated by the preheating gas. Such a heating method using a fluidized bed is superior to other heating methods in terms of the uniformity of the temperature of the seed particles. Therefore, it is possible to more effectively suppress the decrease in the uniformity of the temperature in the granulator (GR) and the uniformity of drying.

[0021] As described above, the particle processing method of the present invention includes the seed particle adjustment step (sc), so that the uniformity of temperature and the uniformity of drying in the granulator (GR) can be suppressed. Therefore, according to the present invention, particles uniformly dried to a desired level and having a desired particle size can be stably granulated. BRIEF DESCRIPTION OF THE DRAWINGS

[0022] [ Figure 1 ] is a process flow chart showing one embodiment of the method and apparatus of the present invention.

[0023] [ Figure 2 ] is a process flow chart showing another embodiment of the method and apparatus of the present invention. DETAILED DESCRIPTION

[0024] <Granulation process (gr)>

[0025] In the present invention, the granulation step (gr) is a step of granulating by coating the surface of the seed particles heated in the seed particle conditioning step (sc) with a coating substance in a high temperature atmosphere. In addition, the granulation device (GR) is a device for granulating by coating the surface of the seed particles heated by the seed particle conditioning device (SC) with a coating substance in a high temperature atmosphere.

[0026] The granulation method in the granulation step (gr) is not particularly limited, as long as it is a method of coating the surface of the seed particles with a coating substance in a high-temperature atmosphere. For example, a method of coating the surface of the seed particles with a coating solution containing the coating substance by spraying the seed particles can be used. According to this method, a droplet-shaped solution adheres to the surface of the seed particles and is dried, and particles larger than the seed particles can be granulated.

[0027] As such a granulation method, from the viewpoint of uniformity of the coating state and uniformity of drying, a granulation method based on a fluidized bed method for granulation and a granulation method based on a fluidized bed / jetted bed method for granulation are preferred, and a granulation method based on a fluidized bed / jetted bed method is particularly preferred. However, the granulation method is not limited thereto, and other methods may also be used. As other methods, for example, a granulation method based on a tumbling granulation method or a stirring granulation method may be cited.

[0028] In the granulation process (gr), when granulation is performed based on a fluidized bed method or a fluidized bed / jetted bed method, a fluidized bed of seed particles is formed by supplying heated fluidizing gas to the seed particles from the bottom. "Fluidized bed" refers to a layered space containing floating and flowing seed particles. "Fluidizing gas" refers to a gas that is supplied roughly evenly to the seed particles from the bottom through a member such as a porous plate in order to form such a fluidized bed. Furthermore, the meaning of "seed particles" in the granulation process (gr) includes not only seed particles before granulation (seed particles that are not coated with anything at the time of supply), but also seed particles in the middle of granulation (seed particles coated to some extent by a coating material).

[0029] When granulation is performed by a fluidized bed method, the surface of the seed particles is coated with the coating substance by spraying a solution containing the coating substance onto the seed particles in the fluidized bed. The solution containing the coating substance may be sprayed from a position different from the supply position of the fluidizing gas, or may be sprayed together with the fluidizing gas. It is particularly preferred to spray together with the fluidizing gas.

[0030] On the other hand, in the case of granulation based on the fluidized bed / jetted bed method, not only a fluidized bed is formed, but also a jetted bed is formed by spraying heated jet-forming gas from the bottom to the seed particles. "Jetted bed" refers to a protruding space containing floating and up-and-down flowing seed particles. "Jet-forming gas" refers to a gas locally sprayed from the bottom to the seed particles in order to form such a jetted bed. In the case of granulation based on the fluidized bed / jetted bed method, the solution containing the coating material is preferably sprayed together with the jet-forming gas.

[0031] In the granulation step (gr), the coating state and the drying state can be adjusted by granulating in a high temperature atmosphere. "Granulating in a high temperature atmosphere" means granulating in a gas at a temperature higher than normal temperature (atmospheric temperature). Figure 1 In the embodiment shown, the temperature of the gas in at least the area where granulation is performed in the granulation device (GR) is higher than normal temperature. The temperature of the particles also becomes the same temperature as the atmosphere. The gas forming the atmosphere is typically air. However, the present invention is not limited to this, and gases other than air such as nitrogen may also be used.

[0032] Regarding the gas forming the above-mentioned atmosphere in the granulation step (gr), for example, in the case of granulation based on the fluidized bed method, it is a gas containing a gas supplied to form a fluidized bed, and in the case of granulation based on the fluidized bed / spouted bed method, it is a gas containing a gas supplied to form a fluidized bed and a gas supplied to form a spouted bed. For example, by appropriately heating the gas supplied for such a purpose in advance and then supplying it, the temperature of the gas in the area where granulation is performed can be adjusted. The specific temperature of the atmosphere for granulation is not particularly limited and can be appropriately determined according to the type of target granular product. However, it is preferably 80°C to 140°C. For example, in the case of manufacturing particles such as urea particles, it is more preferably 95°C to 120°C, and particularly preferably 110°C to 120°C. In addition, for example, in the case of manufacturing particles such as urea particles, the temperature of the solution containing the coating substance is preferably 125°C to 145°C.

[0033] The supply pressure or ejection pressure, supply speed or ejection speed, and supply flow rate or ejection flow rate of the fluidizing gas and the jetting gas can be appropriately adjusted in a manner that can appropriately form a fluidized layer and a jetted layer according to the various conditions such as the particle size, weight, and amount of the seed particles used and the particles after granulation. In addition, the spray pressure, spray speed, and spray flow rate of the solution containing the coating substance can also be appropriately adjusted according to the above-mentioned various conditions of the seed particles used and the particles after granulation.

[0034] In the solution containing the coating material used in the granulation step (gr), the concentration of the coating material can be appropriately adjusted in a manner to achieve a good coating state. In addition, before the solution is used in the granulation step (gr), a part of the liquid in the solution can be evaporated in the evaporation step (ev) to increase the concentration of the coating material. The concentration of the coating material in the solution used in the granulation step (gr) can be appropriately adjusted according to various conditions such as the type and particle size of the material of the seed particles and the particles after granulation. For example, in the case of manufacturing particles such as urea particles, the concentration of the coating material in the solution is preferably 94% by mass to 98.5% by mass. The solvent is preferably water. However, the present invention is not limited thereto.

[0035] The average particle size of the particles obtained in the granulation step (gr) is preferably 0.4 mm to 10 mm, more preferably 1 mm to 6 mm. The average particle size is a value measured by a sieving test method in accordance with JIS Z 8815. For example, by classifying particles having such an average particle size, particles of a product size (particles having a target particle size) can be obtained.

[0036] The moisture content of the particles obtained in the granulation step (gr) is preferably 0.5% by mass or less, and more preferably 0.2% by mass or less. The moisture content is a value measured by Karl Fischer titration. Such particles with a low moisture content are excellent in handling properties.

[0037] The particles obtained in the granulation step (gr) are preferably classified in a particle classification step (pc) to recover particles of a product size (particles having a target particle size). The particle classification step (pc) will be described in detail later.

[0038] The gas discharged from the granulation step (gr) is usually mixed with a small amount of dust. It is preferred that the dust-containing gas discharged from the granulation step (gr) is cleaned, for example, in a gas cleaning step (gw) to remove the dust, and the cleaned gas is discharged, while the removed dust is returned to the solution containing the coating material (for example, the solution in the solution tank) for recycling.

[0039] Figure 1 It is a process flow chart showing one embodiment of the method and apparatus of the present invention.

[0040] Figure 1In the process, the seed particles heated by the seed particle adjustment device (SC) are supplied to the fluidized bed / spouted bed granulation device (GR) via pipeline 1. In addition, the solution (containing the coating material) from the solution tank (ST) is supplied to the granulation device (GR) via pipeline 2, the evaporation unit (EV) and the pipeline 3. In the evaporation unit (EV), a part of the liquid in the solution is evaporated to increase the concentration of the coating material. In addition, the jetting gas is supplied to the granulation device (GR) from the pipeline 4, and the fluidizing gas is supplied to the granulation device (GR) from the pipeline 5, thereby forming a fluidized bed and a spouted bed. Furthermore, in the granulation device (GR), the coating material is coated on the surface of the seed particles by spraying the solution containing the coating material together with the jetting gas to perform granulation. The granulated particles are supplied to the particle classification device (PC) via pipeline 6.

[0041] exist Figure 1 In the process, the dust-containing gas discharged from the granulator (GR) is supplied to a gas cleaning device (GW) equipped with a scrubber and the like through a pipeline 7. In the gas cleaning device (GW), the gas is cleaned to remove dust, and the cleaned gas is discharged from a pipeline 8. In addition, the removed dust is dissolved in a solvent and supplied as a solution to a solution tank (ST) through a pipeline 9 for recycling.

[0042] <Particle classification process (pc) and crushing process (cr)>

[0043] The method of the present invention preferably includes a particle classification step (pc) for classifying the particles granulated in the granulation step (gr), and recovering particles of the product size obtained by the classification (particles having a target particle size). In addition, particles smaller than the product size obtained by the classification are also preferably recycled as seed particles. Furthermore, the method of the present invention also preferably includes a crushing step (cr) for crushing large particles exceeding the product size obtained by the classification of the particle classification step (pc), and the particles reduced in size by the crushing are recycled as seed particles.

[0044] The device of the present invention preferably has a particle classifier (PC) for classifying the particles granulated in the granulator (GR), and recovers the particles of the product size obtained by the classification. In addition, the particles smaller than the product size obtained by the classification are also preferably recycled as seed particles. Furthermore, the device of the present invention also preferably has a crushing device (CR) for crushing large particles exceeding the product size obtained by the classification of the particle classifier (PC), and the particles reduced in size by the crushing are recycled as seed particles.

[0045] In the above descriptions, “recycled as seed particles” specifically means used as seed particles in seed particle adjustment or granulation.

[0046] As a classification method in the particle classification step (pc), for example, there is a method of using a screen or a sieve to classify the particles granulated in the granulation step (gr) into particles of a product size, large particles exceeding the product size, and small particles less than the product size. However, the present invention is not limited thereto.

[0047] exist Figure 1 In the process, the particles granulated in the granulating device (GR) are supplied to the particle classifying device (PC) via pipeline 6. Two screens (S1) and (S2) are provided inside the particle classifying device (PC). First, large particles exceeding the product size do not pass through the screen (S1), and other particles pass through. Next, particles of the product size do not pass through the screen (S2), and small particles smaller than the product size pass through. Then, particles exceeding the product size are supplied to the crushing device (CR) via pipeline 10. Particles of the product size are recovered via pipeline 11. Particles smaller than the product size are supplied to the seed particle adjusting device (SC) via pipelines 12 and 14. In addition, the particles crushed to the desired particle size in the crushing device (CR) are supplied to the seed particle adjusting device (SC) via pipelines 13 and 14.

[0048] <Seed Particle Adjustment Step (sc)>

[0049] In the present invention, the seed particle adjustment step (sc) is a step of supplying a preheating gas to the seed particles from the bottom to form a fluidized layer of the seed particles and preheating the seed particles in the fluidized layer. In addition, the seed particle adjustment device (SC) is a device of supplying a preheating gas to the seed particles from the bottom to form a fluidized layer of the seed particles and preheating the seed particles in the fluidized layer.

[0050] As seed particles to be preheated in the seed particle adjustment step (sc), for example, particles obtained by crushing particles smaller than the product size obtained by classification in the previously described particle classification step (pc) and particles exceeding the product size obtained by classification in the previously described particle classification step (pc) can be used. However, the present invention is not limited to these. Particles that have not undergone the particle classification step (pc) can also be used, for example, seed particles prepared in advance like the core supplied to the granulator in Japanese Patent Publication No. 11-137988 can also be used.

[0051] The average particle size of the seed particles preheated in the seed particle conditioning step (sc) is preferably 0.4 mm to 3 mm, more preferably 1 mm to 2 mm. The average particle size is a value measured by the method described above.

[0052] In the seed particle adjustment step (sc), a fluidized bed of the seed particles is formed by supplying a preheating gas to the seed particles from the bottom. That is, the preheating gas is also used as a fluidizing gas. The preheating gas is typically air. However, the present invention is not limited thereto, and gases other than air such as nitrogen may also be used.

[0053] The temperature of the preheating gas in the seed particle conditioning step (sc) is preferably 80° C. to 140° C., and more preferably 90° C. to 120° C. The preheating gas is a preheating gas for suppressing the decrease in the uniformity of the temperature and the uniformity of drying in the granulation device (GR) (particularly near the supply port of the seed particles). Therefore, the temperature of the preheating gas is preferably the same as or similar to the temperature of the atmosphere described above in the granulation step (gr).

[0054] The supply pressure, supply speed and supply flow rate of the preliminary heating gas in the seed particle adjustment step (sc) may be appropriately adjusted so that a fluidized bed can be appropriately formed according to various conditions such as the particle size, weight and amount of the seed particles used.

[0055] As described above, in the present invention, the seed particles before use in the granulation step (gr) are preheated in advance in the seed particle adjustment step (sc), so that the uniformity of temperature and the uniformity of drying in the granulation device (GR) can be suppressed. Furthermore, from the viewpoint of the ease of continuous process and temperature stability, the seed particles heated in the seed particle adjustment step (sc) are preferably supplied to the granulation step (gr) by a method of directly connecting the device and conveying the particles by gravity flow.

[0056] Figure 1 In the process, the crushed particles from the crushing device (CR) are supplied to the seed particle adjustment device (SC) via pipelines 13 and 14. In addition, the particles smaller than the product size from the particle classification device (PC) are supplied to the seed particle adjustment device (SC) via pipelines 12 and 14 to be used as seed particles.

[0057] exist Figure 1 In the process, gas is supplied to the heater (H) via the pipeline 15, and the temperature of the gas is increased by the heat of the steam flowing in the internal pipe 18 of the heater (H). Then, the gas heated by the heater (H) is supplied to the seed particle adjustment device (SC) as a preliminary heating gas via the pipeline 16. By supplying the preliminary heating gas to the seed particles from the lower side, a fluidized bed of seed particles is formed and the seed particles in the fluidized bed are preheated. The preheated seed particles are supplied to the granulation device (GR) via the pipeline 1.

[0058] exist Figure 1In the process, the gas containing dust is discharged from the upper part of the seed particle adjustment device (SC) and supplied to the gas cleaning device (GW) equipped with a scrubber and the like through the pipeline 17. As described above, in the gas cleaning device (GW), the gas is cleaned to remove dust, and the cleaned gas is discharged from the pipeline 8. In addition, the removed dust is dissolved in the solvent to form a solution, and is supplied to the solution tank (ST) through the pipeline 9 for recycling.

[0059] In the above description, if Figure 1 As shown in FIG. 1 , the case where the seed particle conditioning device (SC) and the granulation device (GR) are different devices is described. However, the present invention is not limited to this. For example, Figure 2 As shown, one apparatus comprising a seed particle conditioning zone (SCZ) and a granulation zone (GRZ), ie a seed particle conditioning and granulation apparatus (SC / GR), may be used.

[0060] exist Figure 2 In the seed particle conditioning and granulation device (SC / GR), the seed particle conditioning zone (SCZ) and the granulation zone (GRZ) separated by the partition wall 19 respectively perform the same functions as the seed particle conditioning device (SC) and the granulation device (GR) described above. The particles pre-heated in the seed particle conditioning zone (SCZ) are supplied to the granulation zone (GRZ) by falling due to gravity flow. It should be noted that in Figure 2 In order to Figure 1 For the convenience of comparison, the two areas are recorded in a horizontal arrangement, but when the particles are supplied to the granulation zone (GRZ) by falling due to gravity flow, the seed particle adjustment zone (SCZ) within the seed particle adjustment and granulation device (SC / GR) is preferably located above the granulation zone (GRZ).

[0061] <Method for improving existing particle processing device>

[0062] The processing device of the present invention can be realized by improving an existing particle processing device.

[0063] For example, by improving the existing particle processing device having a granulating device (GR) by adding a seed particle adjustment device (SC), the particle processing device of the present invention can be realized (see Figure 1 In this case, in the granulating device (GR), the seed particles heated by the seed particle conditioning device (SC) are coated with a coating material in a high-temperature atmosphere to perform granulation. In addition, for example, by replacing the granulating device (GR) in the existing particle processing device with a seed particle conditioning and granulating device (SC / GR), the particle processing device of the present invention can be realized (see Figure 2 In this case, in the granulation zone (GRZ), the seed particles heated in the seed particle conditioning zone (SCZ) are coated with a coating material in a high-temperature atmosphere to perform granulation.

[0064] <Granular products>

[0065] The particles obtained by the present invention are useful as various granular products such as chemical products, medicines, and foods. In particular, the present invention is preferably applied to the granulation using seed particles for the production of granular products in industry. As a preferred specific example of such granular products, urea particles can be particularly cited. However, the present invention is not limited thereto. For example, the present invention can also be applied to the production of granular products other than urea particles such as ammonium nitrate particles and ammonium sulfate particles.

[0066] In the case of obtaining urea particles by the present invention, the seed particles are urea particles, and the solution containing the coating material is a urea aqueous solution. The average particle size of the urea particles as a granular product is preferably 1 mm to 5 mm, and more preferably 2 mm to 4 mm. The water content of the urea particles is preferably 0.5% by mass or less, and more preferably 0.2% by mass or less. The average particle size and water content are values ​​measured by the method described above. Urea particles with such an average particle size and water content are useful in applications such as fertilizers.

[0067] In the present invention, as in the urea particles described above, the seed particles and the coating material are preferably made of the same material. However, the present invention is not limited thereto. Depending on the type of the target granular product, the seed particles and the coating material may also be made of different materials.

[0068] Possibility of Industrial Application

[0069] The present invention is useful as a particle processing method and a particle processing apparatus capable of stably granulating particles that are uniformly dried to a desired level and have a desired particle size.

[0070] Description of Reference Numerals

[0071] SC: Seed particle adjustment device, GR: Granulation device, ST: Solution tank, EV: Evaporation unit, GW: Gas cleaning device, PC: Particle classification device, S1, S2: Screen, CR: Crushing device, H: Heater, 1: Pipeline (seed particles), 2: Pipeline (solution), 3: (solution), 4: Pipeline (fluidizing gas), 5: Pipeline (fluidizing gas), 6: Pipeline (particles), 7: Pipeline (exhaust), 8: Pipeline (cleaned gas) , 9: pipeline (solution containing dissolved dust), 10: pipeline (particles exceeding product size), 11: pipeline (particles of product size), 12: pipeline (particles smaller than product size), 13: pipeline (crushed particles), 14: pipeline (particles smaller than product size and crushed particles), 15: pipeline (gas), 16: pipeline (preparatory heating gas), 17: pipeline (gas containing dust), 18: internal piping (steam), 19: partition wall.

Claims

1. A method for processing particles, comprising: a seed particle conditioning step sc, supplying a preheating gas to the seed particles from below to form a fluidized bed of the seed particles and preheating the seed particles in the fluidized bed; and The granulation step (gr) is performed by coating the surfaces of the seed particles heated in the seed particle conditioning step (sc) with a coating substance in a high-temperature atmosphere.

2. The particle processing method according to claim 1, wherein: The temperature of the preliminary heating gas is 80°C to 140°C.

3. The particle processing method according to claim 1, wherein: In the granulation step (gr), the temperature of the gas forming the high temperature atmosphere is 80°C to 140°C.

4. A particle processing device, comprising: A seed particle conditioning device (SC) supplies a preheating gas to the seed particles from below to form a fluidized bed of the seed particles and preheat the seed particles in the fluidized bed, and The granulating device GR performs granulation by coating the surfaces of the seed particles heated by the seed particle adjusting device SC with a coating substance in a high-temperature atmosphere.

5. A particle processing device, which has a seed particle conditioning and granulation device (SC / GR), wherein the seed particle conditioning and granulation device (SC / GR) comprises: a seed particle conditioning zone (SCZ) that supplies a preheating gas to the seed particles from below to form a fluidized bed of the seed particles and preheat the seed particles in the fluidized bed; and The granulation zone GRZ performs granulation by coating the surfaces of the seed particles heated in the seed particle conditioning zone SCZ with a coating substance in a high-temperature atmosphere.

6. A method for improving an existing particle processing device, wherein the existing particle processing device has a granulation device (GR) that granulates by coating a coating substance on the surface of seed particles in a high-temperature atmosphere; The method for improving the conventional particle processing device is characterized in that: A seed particle conditioning device (SC) is added to the existing particle processing device, wherein the seed particle conditioning device (SC) forms a fluidized bed of the seed particles by supplying a pre-heating gas to the seed particles from the bottom and pre-heats the seed particles in the fluidized bed; and in the granulation device (GR), granulation is performed by coating the seed particles heated by the seed particle conditioning device (SC) with a coating material in a high-temperature atmosphere; or, The granulation device, i.e., GR, is replaced with a seed particle regulating and granulation device, i.e., SC / GR. The seed particle regulating and granulation device, i.e., SC / GR, includes a seed particle regulating zone, i.e., SCZ, and a granulation zone, i.e., GRZ. The seed particle regulating zone, i.e., SCZ, forms a fluidized bed of the seed particles and preheats the seed particles in the fluidized bed by supplying preheating gas to the seed particles from the bottom. The granulation zone, i.e., GRZ, granulates by coating the surfaces of the seed particles heated in the seed particle regulating zone, i.e., SCZ, with a coating substance under a high-temperature atmosphere. In the granulation zone, i.e., GRZ, granulates the seed particles heated in the seed particle regulating zone, i.e., SCZ, with a coating substance under a high-temperature atmosphere.

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