A fluidized bed spray granulation device for flusilazole and thiocarbamates

Abstract

This invention belongs to the field of fluidized bed spray granulation technology, and provides a fluidized bed spray granulation device for fluopyram·cymoxanil water-dispersible granules. The device includes a fluidized bed tower with a discharge pipe connected to its bottom; an air inlet pipe connected to the bottom of the fluidized bed tower; an exhaust pipe connected to the top of the fluidized bed tower; a cyclone separator connected to the other end of the exhaust pipe; an extraction pipe connected to the upper part of the cyclone separator; and an induced draft fan installed on the extraction pipe. By relying entirely on the existing structure of the original fluidized bed equipment, the induced draft fan power, and the fine powder recycling system, only simple welding modifications to the main body of the equipment are required. No new power units such as fans and motors are needed, and no adjustments to the original airflow design are required. The modification can be completed simply by coaxially nesting a screen cylinder assembly inside the discharge pipe and connecting a recycling hose. It can be quickly disassembled and reassembled, restoring the equipment to its original factory state at any time. The modification cost is low, and it is compatible with most models of top-spray fluidized bed granulators on the market.

Description

Technical Field

[0001] This invention relates to the field of fluidized bed spray granulation technology, and specifically to a granulation equipment for fluopyram·cymoxanil water-dispersible granules, specifically a fluidized bed spray granulation device for fluopyram·cymoxanil water-dispersible granules. Background Technology

[0002] Fluidized bed spray granulators, also known as one-step granulators, are core equipment in the production of pesticide water-dispersible granules and pharmaceutical granules. They can complete the entire process of material mixing, spray granulation, and drying within a single sealed tower, offering advantages such as high production efficiency, good product particle uniformity, and a high degree of automation. Currently, they are widely used in the fields of pesticides, pharmaceuticals, and food solid dosage forms. The core structure of a conventional fluidized bed granulator includes a tower body, fluidized distribution plate, inlet air filtration and heating system, top cyclone separator, induced draft fan, bottom discharge port, discharge pipe, and discharge valve. During production, the unformed ultrafine powder from the granulation section is carried to the top of the tower by the fluidizing air, where it undergoes coarse separation by the matching cyclone separator. The separated fine powder can be returned to the tower for reuse via a return pipe, while the finished granules, after granulation and drying, are discharged through the bottom discharge port.

[0003] In actual industrial production, existing technologies for handling fine powder entrained in finished product particles are mainly divided into two categories: offline screening and online screening. Offline screening is currently the mainstream process in the industry. Finished product particles discharged from fluidized beds generally contain 10% to 20% unformed ultrafine powder, which cannot be removed by the cyclone separation system at the top of the tower. The finished product after discharge must be conveyed to an offline vibrating screen or rotary vibrating screen for secondary screening to remove the fine powder before it can be packaged. Online screening is adopted by a few companies and is mainly divided into two types: external and internal. External online screening involves connecting a vibrating screen, air classifier, or other equipment to the end of the discharge pipe, and adding power units such as a vibrating motor and a conveying fan to achieve synchronous screening during the discharge process. Internal online screening involves installing a simple straight-through screen structure inside the discharge pipe, relying on the gravity of the material to achieve simple screening of finished product and fine powder.

[0004] However, existing technologies have certain limitations: offline screening processes require additional conveying and screening steps, resulting in long production cycles and low efficiency per batch. Furthermore, a large amount of pesticide dust is released during screening, posing serious environmental violations and occupational health hazards to operators. The screened fine powder cannot be reused in a closed loop, leading to significant waste of high-value active ingredients. External online screening solutions require multiple additional power units, resulting in high equipment modification costs. They also necessitate alterations to the existing fluidized bed's discharge pipeline and airflow design, which can easily disrupt the stable fluidization state within the tower, causing low-melting-point active ingredients to melt and adhere to the walls, and easily hydrolyzed active ingredients to absorb moisture and degrade, severely impacting the content of active ingredients and storage stability of the product. The existing built-in straight-through screen structure lacks a vortex-enhanced screening design and relies solely on gravity for screening. This results in incomplete separation of the finished product from the fine powder, low screening efficiency, and easy clogging of the screen by ultrafine powder. Furthermore, it lacks a matching closed negative pressure recovery structure, making it impossible to seamlessly integrate with the existing fine powder recycling system in the fluidized bed. The screened fine powder still suffers from dust leakage and cannot be recycled, failing to meet the needs of continuous industrial production. Summary of the Invention

[0005] The purpose of this invention is to provide a fluidized bed spray granulation device for fluopyram·cymoxanil water-dispersible granules. Through structural optimization of the built-in sieve cylinder assembly, the main fluidized bed equipment can be simply modified without adding any power unit. It relies entirely on the system pressure difference formed by the original main fan of the fluidized bed to simultaneously complete cyclone enhanced screening, closed-loop recovery and reuse of fine powder while discharging the material. This completely solves the technical pain points of low screening efficiency, dust leakage, inability to reuse fine powder, and high modification costs in the existing technology.

[0006] To achieve the above objectives, the present invention adopts the following technical solution: A fluidized bed spray granulation device for fluopyram·cymoxanil water-dispersible granules includes a fluidized bed tower body, the bottom of which is connected to a discharge pipe; It also includes an air inlet pipe connected to the bottom of the fluidized bed tower, an exhaust pipe connected to the top of the fluidized bed tower, a cyclone separator connected to the other end of the exhaust pipe, an exhaust pipe connected to the upper part of the cyclone separator, and an induced draft fan installed on the exhaust pipe. The discharge pipe is coaxially nested with an internal screen cylinder assembly; an annular cavity is reserved between the outer wall of the internal screen cylinder assembly and the inner wall of the discharge pipe; sealing positioning components are fixedly connected to both ends of the internal screen cylinder assembly, and the outer edge of the sealing positioning component is interference-fitted with the inner wall of the discharge pipe to completely seal both ends of the annular cavity, forming a closed annular cavity. The built-in screen cylinder assembly includes an integrally formed hollow cylinder; a swirl guide is fixed on the inner wall of the discharge pipe inlet end of the hollow cylinder near the fluidized bed tower; a screen section penetrating the cylinder wall is provided on the side wall of the hollow cylinder corresponding to the position of the swirl guide. The discharge pipe is equipped with a fine powder recovery pipe, which is located behind the cyclone guide and between the sealing and positioning components at both ends; the fine powder recovery pipe is connected to the exhaust pipe at the top of the fluidized bed tower through a fine powder recycling pipeline.

[0007] The above technical solution further includes: The swirl guide is a spiral guide blade; the outer edge of the guide blade is welded and fixed to the inner wall of the hollow cylinder, the inner edge converges towards the central axis of the cylinder, and a central rod is connected to its center, the end of the rod being tapered.

[0008] The screen segment is made of 316L stainless steel perforated mesh or precision woven mesh, and the axial length of the screen segment is the same as the axial length of the guide vane.

[0009] The sealing and positioning component is a 316L stainless steel annular plug integrally formed with the hollow cylinder, and a fluororubber O-ring is provided on its outer edge; annular grooves are opened on the side walls at both ends of the hollow cylinder, and the sealing ring is snapped and fixed in the annular grooves. The outer diameter of the sealing ring protrudes from the outer wall of the hollow cylinder and is interference-fitted with the inner wall of the discharge pipe.

[0010] A ball valve is connected in series on the fine powder recycling pipeline, and the fine powder recycling pipeline is an anti-static PU hose or a 316L stainless steel pipe.

[0011] The bottom of the cyclone separator is connected to a powder collection bin. A shut-off valve is installed at the bottom outlet of the powder collection bin. The outlet of the shut-off valve is connected to the granulation section of the fluidized bed tower through the original return pipeline of the fluidized bed tower.

[0012] The discharge fluidizing air carries the finished product particles and entrained fine powder into the hollow cylinder of the built-in screen cylinder assembly. Under the action of the swirling guide at the feed end of the hollow cylinder, the gas-solid two-phase flow is forced to form a stable axial swirling flow. Under the action of centrifugal force, the qualified finished product particles with larger particle sizes tend to adhere to the inner wall of the hollow cylinder and flow downward along the wall, while the fine powder with smaller particle sizes is more likely to pass through the screen section under the action of centrifugal force.

[0013] The fine powder recovery pipe is connected to the exhaust pipe at the front end of the cyclone separator through the fine powder reuse pipeline. The negative pressure in the exhaust pipe at the air inlet end of the cyclone separator is used to continuously draw the fine powder in the annular wall cavity into the exhaust pipe at the front end of the cyclone separator. After merging with the airflow containing fine powder discharged from the top of the tower, it enters the cyclone separator for gas-solid separation.

[0014] The separated dry fine powder falls into the powder collection bin at the bottom of the cyclone. After being unloaded by the airlock, it is sent back to the granulation section of the fluidized bed tower through the original return pipeline to participate in granulation again, realizing the closed-loop reuse of fine powder.

[0015] The beneficial effects of this invention are: 1. This invention relies entirely on the existing structure, induced draft fan power, and fine powder recycling system of the original fluidized bed equipment. It only requires simple welding modifications to the main body of the equipment, without the need to add new power units such as fans and motors, or adjust the original air path design. The modification can be completed simply by coaxially nesting a screen cylinder assembly in the discharge pipe and connecting a recycling hose. It can be quickly disassembled and reassembled, and the equipment can be restored to its original factory state at any time. The modification cost is low and it is compatible with most models of top-spray fluidized bed granulators on the market.

[0016] 2. This invention forms a stable axial vortex through the spiral guide blades at the feed end, and uses centrifugal force to achieve pre-separation of finished particles and fine powder; at the same time, the tangential airflow formed by the vortex can continuously flush the inner wall of the screen, achieving self-cleaning of the screen, completely solving the problem of screen clogging caused by pesticide ultrafine powder, and meeting the needs of continuous production.

[0017] 3. The entire process of screening, fine powder conveying, and recycling in this invention is completed within a closed pipeline, eliminating any pesticide dust leakage and completely solving the dust leakage problem of offline screening. Furthermore, it can simultaneously recover fine powder carried out from the top of the fluidized bed tower and fine powder entrained in the finished product, significantly reducing the waste of high-value active ingredients and substantially lowering production costs.

[0018] 4. In the granulation and discharge stages of this invention, the induced draft fan does not need to be stopped or its operating parameters need to be adjusted. It does not interfere with the original stable fluidization state and granulation conditions of the fluidized bed. It is compatible with existing mature production processes and can be put into production quickly without the need to readjust the parameters. Attached Figure Description

[0019] Figure 1 This is a schematic diagram of the overall structure of the present invention; Figure 2 yes Figure 1 A magnified view of a portion of point A in the middle.

[0020] In the diagram: 1. Fluidized bed tower body; 2. Discharge pipe; 201. Hollow cylinder; 202. Annular plug; 203. Annular wall cavity; 204. Screen section; 205. Guide vane; 206. Central rod; 207. Fine powder recovery pipe; 208. Fine powder reuse pipe; 3. Air inlet pipe; 4. Cyclone separator; 5. Heat exchanger; 6. Filter; 7. Exhaust fan; 8. Fluidized plate; 9. Raw material liquid pipe; 10. Exhaust pipe; 11. Extraction pipe; 12. Return material pipe; 13. Powder collection bin; 14. Airlock; 15. Ball valve; 16. Baghouse dust collector. Detailed Implementation

[0021] The technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0022] This embodiment focuses on the 120-type top-spray fluidized bed spray granulator commonly used by domestic pesticide companies, for producing 70% fluopyram·cymoxanil water-dispersible granules, as detailed below: Please see Figures 1-2 As shown, a fluidized bed spray granulation device for fluopyram·cymoxanil water-dispersible granules includes a fluidized bed tower 1; a fluidizing plate 8 is provided at the bottom of the fluidized bed tower 1; an air inlet pipe 3 is connected to the bottom of the fluidized bed tower 1, which is the only channel to provide airflow into the fluidized bed tower 1; a heat exchanger 5 and a filter 6 are installed on the air inlet pipe 3. After the air enters the air inlet pipe 3, it first passes through the filter 6 to remove impurities, then exchanges heat through the heat exchanger 5 to raise the temperature of the airflow, and finally passes through the fluidizing plate 8 to be evenly distributed into the fluidized bed tower 1.

[0023] Please refer to it again. Figure 1 As shown, an exhaust pipe 10 is connected to the top of the fluidized bed tower 1 to discharge dust-laden airflow (mainly containing unbonded fluopyram technical powder, cymoxanil technical powder, as well as ultrafine powders such as dispersants and wetting agents, and aqueous solutions of binders, etc.). The other end of the exhaust pipe 10 is connected to a cyclone separator 4. An exhaust pipe 11 is connected to the upper part of the cyclone separator 4. An induced draft fan 7 is installed on the exhaust pipe 11. The induced draft fan 7 is the airflow power source for the entire system of fluidized bed tower 1 and cyclone separator 4. Specifically, the induced draft fan 7 continuously draws air into the exhaust pipe 11, and then draws air into the cyclone separator 4 and the fluidized bed tower 1 respectively, so that positive pressure is formed inside the fluidized bed tower 1.

[0024] Specifically, because the induced draft fan 7 continuously draws air from the end, fresh outdoor air is continuously drawn into the system from the air inlet pipe 3 and flows along the fixed air path: outdoor air → filtered clean → heat exchange and temperature rise → air inlet chamber at the bottom of fluidized bed tower 1 → passes through fluidized plate 8 → enters the fluidized bed tower 1; the material in the fluidized bed tower 1, the fluidized plate 8, the cyclone separator 4 at the rear end, and the bag filter 16 all create resistance to the airflow. The "speed of air entering the tower" and the "speed of air being drawn away by the induced draft fan 7" form a dynamic balance, ultimately allowing the fluidized bed tower 1 to stably maintain a slightly positive pressure that is 500 to 2000 Pa higher than the outdoor atmospheric pressure.

[0025] At the bottom of the cyclone separator 4配套的旋风分离器4 associated with the fluidized bed tower body 1, a sealed powder collection bin 13 is fixed. At the bottom discharge port of the powder collection bin 13, a rotary air lock 14 is installed. The discharge port of the air lock 14 is connected to the granulation section inside the fluidized bed tower body 1 through the original factory return pipeline 12 of the fluidized bed tower body 1.

[0026] In the upper middle part of the fluidized bed tower body 1, there is a raw material liquid pipe 9 for spraying liquid medicines such as adhesive aqueous solution into the middle part of the fluidized bed tower body 1.

[0027] Please refer to again Figure 2 As shown, at the bottom of the fluidized bed tower body 1 corresponding to above the fluidizing plate 8, a discharge pipe 2 is connected. Inside the discharge pipe 2, an internal screen cylinder assembly is coaxially nested; there is an annular cavity with a width of 15 mm reserved between the outer wall of the internal screen cylinder assembly and the inner wall of the discharge pipe 2; at both ends of the internal screen cylinder assembly, sealed positioning parts are fixedly connected, and the outer edge of the sealed positioning parts is in interference fit with the inner wall of the discharge pipe 2, completely sealing both ends of the annular cavity to form a sealed annular wall cavity 203.

[0028] The internal screen cylinder assembly includes a 316L stainless steel hollow cylinder body 201 formed integrally. The outer diameter of the hollow cylinder body 201 is 120 mm, the inner diameter is 100 mm, and the total length is 600 mm; at the inner wall of the end of the hollow cylinder body 201 close to the discharge port of the fluidized bed tower body 1, a swirl guide is welded, with an axial length of 400 mm, for forcibly forming an axial swirl inside the hollow cylinder body 201; at the position of the swirl guide on the side wall of the hollow cylinder body 201, a screen section 204 penetrating the cylinder wall is provided.

[0029] Among them, the swirl guide is a 316L stainless steel spiral guide vane 205. The lead angle of the guide vane 205 is 35°, and the blade thickness is 2 mm; the outer edge of the guide vane 205 is fully welded and fixed to the inner wall of the hollow cylinder body 201, and the inner edge converges towards the central axis of the hollow cylinder body 201. Its center is connected with a central rod 206, and the end of the rod body is conical, playing a guiding role; the screen section 204 is made of 316L stainless steel precision woven mesh or stainless steel punched mesh, the screen hole diameter is 120 mesh, and the axial length of the screen section 204 is the same as the axial length of the guide vane 205.

[0030] The sealed positioning part is a 316L stainless steel annular plug 202 formed integrally with the hollow cylinder body 201. A fluororubber O-ring seal is provided on its outer edge, which is resistant to pesticide corrosion and has a temperature resistance range of -20°C to 120°C; annular clamping grooves (not shown in the figure) are opened on the side walls at both ends of the hollow cylinder body 201, and the sealing ring is clamped and fixed in the annular clamping grooves. The outer diameter of the sealing ring is 152 mm, protruding 2 mm from the outer wall of the hollow cylinder body 201, and is in interference fit with the inner wall of the discharge pipe 2, achieving both sealing and radial positioning.

[0031] A fine powder recovery pipe 207 is provided on the wall of the discharge pipe 2. It is located behind the cyclone guide and between the sealing and positioning parts at both ends. The outer end of the fine powder recovery pipe 207 is welded with a quick-connect coupling (not shown in the figure) to achieve quick disassembly and assembly. The fine powder recovery pipe 207 is connected to the fine powder recycling pipeline 208 through an anti-static PU hose or a 316L stainless steel pipe. The fine powder recycling pipeline 208 is connected to the exhaust pipe 10 at the top of the fluidized bed tower body 1. A ball valve 15 is connected in series on the pipeline as a negative pressure regulating valve to accurately adjust the negative pressure value in the annular wall cavity 203.

[0032] The fluidized bed spray granulation device for fluopyram·cymoxanil water-dispersible granules of the present invention relies on the system negative pressure formed by the original induced draft fan 7 in the fluidized bed tower 1 and the slight positive pressure difference inside the tower to simultaneously realize the continuous closed-loop operation of "discharge-cyclone screening-negative pressure recovery-fine powder reuse" during the discharge process. The specific principle is as follows: The induced draft fan 7 of the fluidized bed tower 1 operates continuously, keeping the exhaust system at the top of the fluidized bed tower 1 (cyclone separator 4, bag filter 16 and connecting pipelines) under negative pressure. Simultaneously, the intake system, under the suction of the induced draft fan 7, maintains a certain slight positive pressure inside the fluidized bed tower 1. When the discharge valve of the discharge pipe 2 is opened, a pressure difference is created between the slight positive pressure inside the tower and the atmospheric pressure outside the discharge pipe 2, thereby generating discharge fluidizing air flowing outward along the discharge pipe 2. This discharge fluidizing air provides power for the material to enter the screen cylinder and achieve screening.

[0033] The discharge fluidizing air carries the finished product particles and entrained fine powder into the hollow cylinder 201 with an internal screen assembly. Under the action of the swirling guide (such as the spiral guide blade 205) set at the feed end of the hollow cylinder 201, the gas-solid two-phase flow is forced to form a stable axial swirling flow. Under the action of centrifugal force, the larger qualified finished product particles tend to adhere to the inner wall of the hollow cylinder 201 and flow downward along the wall, while the smaller fine powder is more likely to cross the screen section 204 under the action of centrifugal force, thereby achieving "pre-stratification", significantly improving screening efficiency and reducing the risk of screen clogging.

[0034] Specifically, fine powder with a particle size smaller than the sieve opening passes through the sieve under the combined action of swirling flow and local negative pressure, and enters the annular cavity 203 formed by the outer wall of the hollow cylinder 201 and the inner wall of the discharge pipe 2. Since the hollow cylinder 201 is equipped with sealing and positioning components at both ends, the annular cavity is sealed to form an annular negative pressure cavity, which is only connected to the fine powder recovery pipe 207 connected to the wall of the discharge pipe 2, thereby ensuring that the fine powder is effectively collected without leakage.

[0035] The fine powder recovery pipe 207 is connected to the exhaust pipe 10 at the front end of the cyclone separator 4 through the fine powder reuse pipe 208. The fine powder in the annular wall cavity 203 is continuously drawn into the exhaust pipe 10 at the front end of the cyclone separator 4 by the negative pressure at the air inlet of the cyclone separator 4. After merging with the airflow containing fine powder discharged from the top of the tower, it enters the cyclone separator 4 for gas-solid separation.

[0036] The separated dry fine powder falls into the powder collection bin 13 at the bottom of the cyclone separator. After being unloaded by the airlock 14, it is sent back to the granulation section of the fluidized bed tower 1 via the original return pipeline 12 to participate in granulation again, realizing the closed-loop reuse of fine powder. The separated humid gas enters the subsequent bag filter 16 and induced draft fan 7 through the exhaust pipe 11 at the top of the cyclone separator 4, and is finally discharged externally to avoid the backflow of humid air affecting the tower's operating conditions and product quality.

[0037] In this embodiment, by relying entirely on the existing structure of the original equipment of the fluidized bed tower 1, the power of the induced draft fan 7, and the fine powder recycling system, only simple welding modifications to the main body of the equipment are required. There is no need to add power units such as fans and motors, nor to adjust the original air path design. The modification can be completed simply by coaxially nesting the screen cylinder assembly in the discharge pipe 2 and connecting a recycling hose. It can be quickly disassembled and reassembled, and the original factory state of the equipment can be restored at any time. The modification cost is low and it is compatible with most models of top-spray fluidized bed granulators on the market.

[0038] It should be noted that, in this document, terms such as “comprising,” “including,” or any other variations thereof are intended to cover non-exclusive inclusion, such that a process, method, article, or apparatus that comprises a list of elements includes not only those elements but also other elements not expressly listed, or elements inherent to such process, method, article, or apparatus.

[0039] Although embodiments of the invention have been shown and described, it will be understood by those skilled in the art that various changes, modifications, substitutions and alterations can be made to these embodiments without departing from the principles and spirit of the invention.

Claims

1. A fluidized bed spray granulation device for fluopyram·cymoxanil water-dispersible granules, comprising a fluidized bed tower (1), wherein a discharge pipe (2) is connected to the bottom of the fluidized bed tower (1); It also includes an air inlet pipe (3) connected to the bottom of the fluidized bed tower (1), an exhaust pipe (10) connected to the top of the fluidized bed tower (1), a cyclone separator (4) connected to the other end of the exhaust pipe (10), an exhaust pipe (11) connected to the upper part of the cyclone separator (4), and an induced draft fan (7) installed on the exhaust pipe (11). Its features are: The discharge pipe (2) has a built-in screen cylinder assembly coaxially nested inside; an annular cavity is reserved between the outer wall of the built-in screen cylinder assembly and the inner wall of the discharge pipe (2); sealing positioning parts are fixedly connected to both ends of the built-in screen cylinder assembly, and the outer edge of the sealing positioning part is interference-fitted with the inner wall of the discharge pipe (2) to completely seal both ends of the annular cavity, forming a closed annular wall cavity (203). The built-in screen cylinder assembly includes an integrally formed hollow cylinder (201); a swirl guide is fixed on the inner wall of the feed end of the discharge pipe (2) of the hollow cylinder (201) near the fluidized bed tower (1); a screen section (204) penetrating the cylinder wall is provided on the side wall of the hollow cylinder (201) corresponding to the position of the swirl guide. The discharge pipe (2) is provided with a fine powder recovery pipe (207) on its pipe wall, which is located behind the swirling guide between the sealing and positioning parts at both ends; the fine powder recovery pipe (207) is connected to the exhaust pipe (10) at the top of the fluidized bed tower (1) through the fine powder recycling pipeline (208).

2. The fluidized bed spray granulation device for fluopyram·cymoxanil water-dispersible granules according to claim 1, characterized in that: The swirl guide is a spiral guide blade (205); the outer edge of the guide blade (205) is welded and fixed to the inner wall of the hollow cylinder (201), the inner edge converges towards the central axis of the cylinder, and a central rod (206) is connected to its center, the end of the rod being conical.

3. The fluidized bed spray granulation device for fluopyram·cymoxanil water-dispersible granules according to claim 2, characterized in that: The screen segment (204) is a 316L stainless steel perforated mesh or precision woven mesh, and the axial length of the screen segment (204) is the same as the axial length of the guide vane (205).

4. The fluidized bed spray granulation device for fluopyram·cymoxanil water-dispersible granules according to claim 1, characterized in that: The sealing and positioning component is a 316L stainless steel annular plug (202) integrally formed with the hollow cylinder (201), and a fluororubber O-ring is provided on its outer edge; the two end side walls of the hollow cylinder (201) are provided with annular grooves, and the sealing ring is snapped and fixed in the annular grooves. The outer diameter of the sealing ring protrudes from the outer wall of the hollow cylinder (201) and is interference-fitted with the inner wall of the discharge pipe (2).

5. The fluidized bed spray granulation device for fluopyram·cymoxanil water-dispersible granules according to claim 1, characterized in that: A ball valve (15) is connected in series on the fine powder recycling pipeline (208), and the fine powder recycling pipeline (208) is an anti-static PU hose or a 316L stainless steel pipe.

6. The fluidized bed spray granulation device for fluopyram·cymoxanil water-dispersible granules according to claim 1, characterized in that: The bottom of the cyclone separator (4) is connected to a powder collection bin (13). A shut-off valve (14) is installed at the bottom outlet of the powder collection bin (13). The outlet of the shut-off valve (14) is connected to the granulation section of the fluidized bed tower (1) through the original return pipeline (12) of the fluidized bed tower (1).

7. The fluidized bed spray granulation device for fluopyram·cymoxanil water-dispersible granules according to claim 1, characterized in that: The discharge fluidizing air carries the finished product particles and entrained fine powder into the hollow cylinder (201) of the built-in screen cylinder assembly. Under the action of the swirling guide at the feed end of the hollow cylinder (201), the gas-solid two-phase flow is forced to form a stable axial swirling flow. Under the action of centrifugal force, the qualified finished product particles with larger particle size tend to adhere to the inner wall of the hollow cylinder (201) and flow downward along the wall, while the fine powder with smaller particle size is more likely to cross the screen section (204) under the action of centrifugal force.

8. The fluidized bed spray granulation device for fluopyram·cymoxanil water-dispersible granules according to claim 7, characterized in that: The fine powder recovery pipe (207) is connected to the exhaust pipe (10) at the front end of the cyclone separator (4) through the fine powder reuse pipe (208). The negative pressure in the exhaust pipe (10) at the air inlet end of the cyclone separator (4) is used to continuously draw the fine powder in the annular wall cavity (203) into the exhaust pipe (10) at the front end of the cyclone separator (4). After merging with the airflow containing fine powder discharged from the top of the tower, it enters the cyclone separator (4) for gas-solid separation. After separation, the dry fine powder falls into the powder collection bin (13) at the bottom of the cyclone. After being unloaded by the airlock (14), it is sent back to the granulation section of the fluidized bed tower (1) by the original return pipeline (12) to participate in granulation again, so as to realize the closed-loop reuse of fine powder.

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