A fluidized bed granulation device with anti-sticking wall for MOCA crystal

Abstract

The application discloses a kind of anti-sticking wall fluidized bed granulation device for MOCA crystalline body, including vertically arranged barrel, the feed inlet being arranged in the upper portion of barrel and the exhaust port being arranged in the top of barrel, gas distribution plate is equipped in barrel, and fluidization air chamber is arranged below gas distribution plate, gas distribution plate has central porous plate portion and annular gas portion around its periphery;The inner wall of barrel is fixed with a plurality of longitudinally extending flow guide portions along the circumference, each flow guide portion forms longitudinally through slit passage with adjustable cross-sectional area between the inner wall of barrel, the lower end of slit passage is communicated with the airflow passage of annular gas portion;When airflow enters slit passage through annular gas portion and flows longitudinally, isolated gas layer is formed on the surface of inner wall of barrel to prevent particle adhesion.The application forms uniform and stable isolated gas layer on the surface of inner wall of barrel by gas distribution plate and flow guide portion, solves the problem of particle adhesion with inner wall of barrel due to surface softening or melting of MOCA crystalline body.

Description

Technical Field

[0001] This invention relates to the field of fluidized bed technology, and more particularly to a fluidized bed granulation apparatus for preventing MOCA crystals from sticking to the wall. Background Technology

[0002] MOCA, a key polyurethane curing agent, plays a crucial role in the industrial sector, typically existing in crystalline form. In the context of industrial production, converting MOCA crystals into uniform granular products is essential to more efficiently meet the demands of storage, transportation, and subsequent use. Fluidized bed granulation technology, with its unique advantages, has become an ideal choice for achieving this goal. This technology boasts numerous advantages, including high heat and mass transfer efficiency, precise and controllable particle size, and continuous and stable operation, and has been widely applied in many industries such as chemical, pharmaceutical, and food processing.

[0003] Traditional fluidized bed granulation equipment typically consists of core components such as a vertical cylinder, feed inlet, exhaust outlet, gas distribution plate, and fluidizing chamber. Its working principle involves using an upward airflow to fluidize powder or crystalline particles, while simultaneously promoting particle growth through the spraying of binders or molten liquid, ultimately forming a product that meets the required specifications.

[0004] However, during fluidized bed granulation of MOCA crystals, the unique physicochemical properties of the MOCA crystal surface make it prone to softening and even melting during the granulation process. This characteristic leads to easy adhesion between particles and between particles and the inner wall of the equipment, especially near the inner wall of the cylinder where the airflow velocity is relatively low and a boundary layer effect exists. Furthermore, fine particles or semi-molten MOCA crystals continuously adhere to the inner wall of the cylinder, gradually accumulating and forming a wall crust over time. This not only disrupts the originally stable fluidization state within the fluidized bed, resulting in uneven particle distribution and reduced granulation yield, affecting product quality and output, but also drastically deteriorates the heat transfer performance of the wall surface, affecting the thermal balance of the entire granulation process and reducing production efficiency. In addition, cleaning after wall crust formation is extremely difficult, requiring significant manpower, resources, and time. More seriously, when wall crust formation reaches a certain extent, it can even block the entire unit, forcing production to stop and severely impacting the continuity and stability of production.

[0005] Therefore, how to provide a fluidized bed granulation device for preventing MOCA crystals from sticking to the wall is a problem that urgently needs to be solved by those skilled in the art. Summary of the Invention

[0006] One object of the present invention is to provide a fluidized bed granulation device for preventing MOCA crystals from sticking to the wall. In this invention, when the gas flow enters the slit channel through the annular gas section and flows longitudinally, it enters the longitudinally penetrating slit channel formed between the guide section and the inner wall of the cylinder, forming an isolation gas layer on the surface of the inner wall of the cylinder to prevent particle adhesion.

[0007] According to an embodiment of the present invention, a fluidized bed granulation device for preventing MOCA crystals from sticking to the wall includes a vertically arranged cylinder, a feed inlet disposed at the upper part of the cylinder, and an exhaust port disposed at the top of the cylinder. A gas distribution plate is provided inside the cylinder, and a fluidizing air chamber is disposed below the gas distribution plate. The gas distribution plate has a central porous plate section and an annular gas section surrounding it. The inner wall of the cylinder is fixed with multiple longitudinally extending guide sections along the circumference. Each guide section forms a longitudinally penetrating slit channel with an adjustable cross-sectional area between itself and the inner wall of the cylinder. The lower end of the slit channel is connected to the airflow channel of the annular air section. When the airflow enters the slit channel through the annular air section and flows longitudinally, an isolation air layer is formed on the surface of the inner wall of the cylinder to prevent particle adhesion.

[0008] Furthermore, the surface of the annular gas section is provided with multiple inclined air holes, the outlet end of each air hole faces the inner wall of the cylinder, and the inclination angle of the air hole gradually increases along the direction away from the inner wall of the cylinder. Multiple pores are distributed circumferentially along the annular air section and are evenly spaced. Alternatively, when the central arc of each pore is located on the same circumference, multiple pores are continuously distributed in a sequence or with overlapping ends, so that the isolation air layer completely covers the inner wall of the cylinder.

[0009] Furthermore, the annular gas section is provided with multiple jet structures, each jet structure having its outlet facing the inner wall of the cylinder and tilting upwards, and corresponding to the corresponding slit channel. The inlet end of each jet structure is connected to the corresponding air hole.

[0010] Furthermore, the vents are groove-shaped, and at least two vents are at different radial distances from the inner wall of the cylinder. The width of the vents gradually decreases along the direction away from the inner wall of the cylinder, so that the pressure of the airflow after entering the slit channel through different vents is the same.

[0011] Furthermore, the flow guide is fixed to the inner wall of the cylinder by multiple connecting bodies spaced apart along its longitudinal direction. The end of the flow guide away from the gas distribution plate is provided with a guide part extending circumferentially along the cylinder. The guide part is used to guide the airflow from the slit channel to flow closely against the inner wall of the cylinder.

[0012] Furthermore, each guide section is provided with at least two connecting bodies, and multiple connecting bodies are longitudinally distributed along the central axis of the guide section. The cross-sectional area of ​​the connecting bodies is smaller than that of the guide section, so that when the airflow passes through the connecting bodies, it continues to flow in the same direction along both sides of the connecting bodies.

[0013] Furthermore, the flow guide is divided into several segments along the height direction of the cylinder, and adjacent segments are joined end to end; in the circumferential direction of the cylinder, multiple flow guides are distributed at intervals, or adjacent flow guides are attached to each other.

[0014] Furthermore, a regulating valve is installed on the jet structure; the slotted air hole is connected to a vent pipe, and the vent pipe is also equipped with a regulating valve.

[0015] Furthermore, an annular baffle is provided along the edge of the side of the perforated plate facing the fluidizing chamber, which separates the perforated plate from the annular air section.

[0016] Furthermore, the jet structure of the annular gas section is arranged in multiple staggered layers in the circumferential direction, with each layer of jet structure having an outlet facing a different elevation angle.

[0017] The beneficial effects of this invention are: This invention forms a uniform and stable isolation gas layer on the inner wall surface of the cylinder through structures such as a gas distribution plate and a flow guide. This fundamentally solves the problem of MOCA crystal particles adhering to the inner wall of the cylinder due to the easy softening or melting of the surface, thus avoiding wall adhesion. Furthermore, the distance between the flow guide and the inner wall of the cylinder is adjustable, and the cross-sectional area of ​​the slit channel can be flexibly changed according to process conditions such as gas flow rate and MOCA crystal characteristics. This allows for precise control of the thickness and strength of the isolation gas layer, ensuring the best anti-adhesion effect under different working conditions. In Embodiment 1 of the present invention, the annular air section is equipped with a jet structure that works in conjunction with the air hole. The outlet is precisely oriented toward the inner wall of the cylinder and tilted upward, so that the airflow fits more closely to the curved surface of the inner wall of the cylinder, forming a uniform and stable airflow isolation layer, which promptly disperses particles that are about to adhere. Furthermore, each jet structure corresponds one-to-one with the corresponding slit channel, and the inlet end is connected to the air hole to avoid chaotic airflow scattering, reduce energy loss, and improve utilization efficiency. In Embodiment 2 of the present invention, the pores are continuously distributed along the circumference to ensure that the isolation air layer completely covers the inner wall of the cylinder, eliminates blind spots in protection, and prevents particle adhesion in all directions. The pore shape is designed as a groove. By controlling the rate of change of the pore width, the pressure is the same when the airflow ejected from the pores at different radial distances enters the slit channel, ensuring uniform and stable airflow, which is conducive to forming an isolation air layer with uniform thickness and consistent strength. Attached Figure Description

[0018] The accompanying drawings are provided to further illustrate the invention and form part of the specification. They are used in conjunction with embodiments of the invention to explain the invention and do not constitute a limitation thereof. In the drawings: Figure 1 This is a perspective view of a fluidized bed granulation device for preventing MOCA crystals from sticking to the wall, as proposed in this invention. Figure 2 This is a cross-sectional view of Embodiment 1 of the present invention; Figure 3 This is a top view of the gas distribution plate in Embodiment 1 of the present invention; Figure 4 This is a cross-sectional view of Embodiment 2 of the present invention; Figure 5 This is a top view of the gas distribution plate in Embodiment 2 of the present invention when the number of pores is even; Figure 6 This is a top view of the gas distribution plate in Embodiment 2 of the present invention when the number of pores is odd. Figure 7 This is a top view of the gas distribution plate in Embodiment 3 of the present invention; Figure 8 This is a top view of the gas distribution plate when the air jet structure is installed in the vent according to Embodiment 1 of the present invention; Figure 9 This is a top view of the gas distribution plate when the jet structure is installed in the vent in Embodiment 2 of the present invention; Figure 10 This is a cross-sectional view of the structure of Embodiment 2 proposed in this invention; Figure 11 This is a structural cross-sectional view of Embodiment 1 of the present invention.

[0019] In the diagram: 1. Cylinder; 11. Feed inlet; 12. Exhaust outlet; 2. Gas distribution plate; 21. Perforated plate; 22. Annular gas section; 221. Air vent; 3. Fluidizing air chamber; 4. Guide section; 41. Slit channel; 42. Isolation gas layer; 43. Guide section; 5. Jet structure; 6. Connector; 7. Vent pipe; 8. Annular baffle. Detailed Implementation

[0020] The present invention will now be described in further detail with reference to the accompanying drawings. These drawings are simplified schematic diagrams, illustrating only the basic structure of the invention, and therefore only show the components relevant to the invention.

[0021] refer to Figures 1-11 A fluidized bed granulation device for preventing MOCA crystals from sticking to the wall includes a vertically arranged cylinder 1, a feed inlet 11 located at the top of the cylinder 1, and an exhaust port 12 located at the top of the cylinder 1. Inside the cylinder 1, a fluidizing air chamber 3 and a gas distribution plate 2 are arranged sequentially from bottom to top.

[0022] The gas distribution plate 2 includes a centrally located porous plate portion 21 and an annular gas portion 22 surrounding the porous plate portion 21. Multiple longitudinally extending guide portions 4 are uniformly fixedly installed circumferentially on the inner wall of the cylinder 1. Each guide portion 4 forms a longitudinally penetrating slit channel 41 with the inner wall of the cylinder 1, and the lower end of the slit channel 41 is connected to the airflow channel of the annular gas portion 22. When the airflow enters the slit channel 41 from the annular gas portion 22 and flows upward longitudinally, a uniform and stable isolation gas layer 42 is formed on the inner wall surface of the cylinder 1, effectively preventing particles from adhering to the inner wall of the cylinder 1. This fundamentally solves the problem of particle adhesion to the inner wall of the cylinder 1 caused by the easy softening or melting of the crystal surface during the fluidized bed granulation of MOCA crystals, avoiding the occurrence of wall slagging, ensuring a stable fluidization state in the fluidized bed, enabling particles to be uniformly distributed and grown, and significantly improving the granulation quality and yield.

[0023] In addition, the distance between the flow guide 4 and the inner wall of the cylinder 1 is adjustable, that is, the cross-sectional area of ​​the slit channel 41 can be changed according to the actual situation. In practical applications, the staff can flexibly adjust the size of the slit channel 41 according to the on-site process conditions, such as gas flow rate and the characteristics of MOCA crystals, so as to precisely control the thickness and strength of the isolation gas layer 42, and ensure that the best anti-adhesion effect can be achieved under different working conditions, thereby improving the adaptability and versatility of the device.

[0024] Multiple inclined air holes 221 are formed through the surface of the annular air section 22, and the outlet ends of the air holes 221 all face the inner wall of the cylinder 1, forming a targeted airflow guide. Furthermore, when viewed from the position of the air hole 221 near the center of the annular air section 22 towards the direction away from the inner wall of the cylinder 1, the inclination angle of the air hole 221 gradually increases. That is to say, the closer the air hole 221 is to the outer side of the annular air section 22, the larger its angle with the horizontal direction. Since the outlet ends of each air hole 221 face the inner wall of the cylinder 1, and the inclination angle gradually increases along the direction away from the inner wall of the cylinder 1, when the airflow is ejected from the air hole 221, a distinct and uniformly distributed airflow isolation layer can be formed near the inner wall of the cylinder 1. The vents 221 near the inner wall of the cylinder 1 have a relatively small tilt angle, and the airflow impacts the inner wall at a gentler angle, which can initially disperse the fine particles that are about to adhere. Meanwhile, the airflow ejected from the vents 221 far from the inner wall and with a larger tilt angle can further supplement and strengthen the isolation layer, preventing particles from accumulating and adhering at the airflow boundary layer. Compared with the single-angle vent 221 design, the multi-angle and multi-layer airflow action mode greatly improves the anti-adhesion effect and effectively avoids the phenomenon of MOCA crystals forming on the inner wall of the cylinder 1.

[0025] Example 1: like Figures 2-3As shown, in the annular gas section 22, multiple air holes 221 are evenly spaced along its circumference. Multiple jet structures 5 are also provided on the annular gas section 22. The jet structures 5 cooperate with the air holes 221, and the outlet direction of each jet structure 5 is precisely facing the inner wall of the cylinder 1 and tilted upwards at a certain angle. This allows the ejected airflow to move along a specific trajectory, better conforming to the shape of the inner wall of the cylinder 1 and meeting the airflow distribution requirements in the fluidized bed granulation process. Compared with the traditional direct injection structure, this tilted jet method allows the airflow to better conform to the curved surface of the inner wall of the cylinder 1, forming a uniform and stable airflow isolation layer on the wall surface. Simultaneously, the airflow flows upwards along the inner wall of the cylinder 1, effectively dispersing fine MOCA crystal particles that are about to adhere, thus preventing particle accumulation and wall agglomeration, and greatly improving the anti-adhesion effect.

[0026] Furthermore, each jet structure 5 is configured one-to-one with a corresponding slit channel 41, ensuring that airflow can enter the slit channel 41 from the jet structure 5, forming an orderly airflow channel. Simultaneously, the inlet end of each jet structure 5 is connected to a corresponding air hole 221, allowing airflow to smoothly flow into the jet structure 5 from the air hole 221, and then into the slit channel 41 via the jet structure 5. Ultimately, an effective isolation air layer 42 is formed on the inner wall surface of the cylinder 1. The precise entry of the jet structure 5 into the slit channel 41 avoids airflow chaos and scattering, reduces airflow energy loss, and improves airflow utilization efficiency. Compared to disordered airflow transmission methods, it can produce a stronger anti-adhesion effect under the same airflow rate.

[0027] Example 2: like Figures 4-6 As shown, in the annular gas section 22, multiple vents 221 are distributed along its circumference. Specifically, when the central arcs of all vents 221 lie on the same circumference, these vents 221 exhibit a continuous distribution, with their ends connected sequentially or overlapping. In practical applications, this method ensures that the isolation gas layer 42 formed by the airflow ejected from the vents 221 completely covers the inner wall of the cylinder 1, thereby preventing MOCA crystal particles from adhering to the inner wall of the cylinder 1 from all directions. It eliminates blind spots on the inner wall surface, ensuring that every part is isolated by the airflow, effectively preventing MOCA crystal particles from adhering at any location, greatly improving the anti-adhesion effect, and guaranteeing the stability and continuity of the fluidized bed granulation process.

[0028] Specifically, each vent 221 is designed in a groove shape, and at least two vents 221 have different radial distances from the inner wall of the cylinder 1. Furthermore, the width of the vents 221 gradually decreases away from the inner wall of the cylinder 1, so that the airflow can reach the same pressure after passing through different vents 221 and entering the slit channel 41. When the airflow enters the gradually narrowing vent 221 from the wider inlet, according to the continuity equation and Bernoulli's principle, the airflow velocity will increase, and the pressure will change accordingly. By precisely controlling the rate of change of the width of the vents 221, the pressure difference caused by the different radial distances of the vents 221 can be offset, ultimately ensuring that the airflow ejected from each vent 221 has the same pressure when entering the slit channel 41. This makes the airflow entering the slit channel 41 more uniform and stable, which is conducive to forming a uniform thickness and consistent strength isolation air layer 42 on the inner wall of the cylinder 1, further improving the anti-adhesion performance.

[0029] To further explain, if the number of pores 221 is even, the width of the pores 221 has two different dimensions, and the central axis of any pore 221 is the axis of symmetry, and the remaining pores 221 are symmetrically arranged relative to this axis of symmetry. If the number of pores 221 is odd, the width of the pores 221 has at least three different dimensions.

[0030] like Figure 8 As shown, the flow guide 4 is firmly fixed to the inner wall of the cylinder 1 by multiple connectors 6, and the connectors 6 are distributed at intervals along the longitudinal direction of the flow guide 4. This ensures the firmness and stability of the connection between the flow guide 4 and the inner wall of the cylinder 1, and avoids unnecessary obstruction of airflow due to the connectors 6 being too dense.

[0031] In one embodiment, the flow guide 4 is divided into several independent segments along the height direction of the cylinder 1. Multiple flow guides 4 are distributed at certain intervals along the circumference of the cylinder 1, with each flow guide 4 remaining relatively independent. They are distributed uniformly or unevenly on the inner wall of the cylinder 1 in the circumferential direction, depending on the actual design requirements and process optimization goals. For example, in areas where airflow uniformity is highly demanding, the flow guides 4 may be distributed more densely; while in areas where the airflow is more stable or the flow guide requirement is relatively low, the intervals can be appropriately increased.

[0032] Adjacent flow guide sections 4 are connected end-to-end to ensure a tight, smooth connection without significant gaps or misalignment. At the joint, special connection structures or processes, such as welding, snap-fit ​​connections, or sealing gaskets, are used to ensure the strength and sealing of the connection, preventing leakage or turbulence of airflow at the joint. In actual fluidized bed granulation devices, the height of the cylinder 1 may be large, and its internal structure may be complex. Dividing the flow guide section 4 into several segments along the height of the cylinder 1 better adapts to changes in the shape and size of the cylinder 1 at different heights. For example, the cylinder 1 may have contracted or expanded sections at certain heights; the multi-segment flow guide section 4 can be flexibly adjusted and installed according to these changes, ensuring that each segment of the flow guide section 4 fits tightly against the inner wall of the cylinder 1.

[0033] In another embodiment, adjacent guide sections 4 are tightly fitted together along the circumferential direction of the cylinder 1 without significant gaps, ensuring that they do not loosen or separate under the impact of airflow and particles. In the circumferential direction, these mutually fitted guide sections 4 form a continuous guide structure, covering the entire area of ​​the inner wall of the cylinder 1, thus creating a more complete and uniform airflow isolation layer 42 on the inner wall of the cylinder 1. This more effectively prevents MOCA crystal particles from contacting the inner wall of the cylinder 1, reducing particle adhesion and accumulation on the wall surface.

[0034] Compared to spaced-out guide sections 4, closely spaced guide sections 4 can eliminate the problem of particle adhesion to the wall caused by airflow channels that may exist due to spacing, especially when processing highly viscous or easily agglomerated particles. Furthermore, the continuous guide structure can guide the airflow to flow more closely against the inner wall of the cylinder 1, enhancing the scouring effect of the airflow on the inner wall of the cylinder 1 and further preventing particle adhesion and deposition. Even if a small number of particles approach the inner wall of the cylinder 1, they will be quickly carried away by the high-speed airflow, keeping the inner wall of the cylinder 1 clean.

[0035] On the other hand, at the end of the flow guide 4 furthest from the gas distribution plate 2, a guide section 43 extending circumferentially along the cylinder 1 is also provided. Specifically, the flow guide 4 is T-shaped or inverted L-shaped, the purpose of which is to guide the airflow flowing out from the slit channel 41. When the airflow ejected upward from the slit channel 41 encounters the inverted L-shaped or T-shaped guide section 43, it is forced to change direction. The guide section 43 forces the airflow to flow close to the inner wall of the cylinder 1, preventing the airflow from diffusing towards the center of the cylinder 1 too early. This allows the air cushion to maintain its wall-hugging motion for a certain distance after leaving the slit outlet, thereby extending the effective protection height of the air cushion.

[0036] Specifically, each flow guide 4 is equipped with at least two connectors 6, and multiple connectors 6 are longitudinally distributed along the central axis of the flow guide 4 to ensure that a stable and reliable connection can be formed between the flow guide 4 and the inner wall of the cylinder 1.

[0037] From a dimensional perspective, the cross-sectional area of ​​the connector 6 is significantly smaller than that of the guide section 4. On one hand, the smaller cross-sectional area allows the connector 6 to provide sufficient connection strength when fixing the guide section 4 to the inner wall of the cylinder 1, ensuring that the guide section 4 will not loosen or shift during airflow impact and device operation. On the other hand, it minimizes interference with airflow. When the airflow flows along a predetermined path within the cylinder 1 and passes through the guide section 4 area, it inevitably encounters the connectors 6. Due to the smaller cross-sectional area of ​​the connector 6, the airflow experiences minimal obstruction as it passes through it. The airflow can smoothly continue flowing in its original direction along both sides of the connector 6 without significant airflow separation or turning. This allows the airflow to maintain good continuity and stability when passing through the guide section 4 area, effectively avoiding airflow turbulence and energy loss caused by an excessively large connector 6.

[0038] Furthermore, such as Figures 8-9 As shown, in Embodiment 1, the jet structure 5 can be presented as a nozzle or a specific jet channel to meet the jetting requirements of airflow under different working conditions and granulation needs. In order to achieve precise control of the airflow ejected by the jet structure 5, a regulating valve is installed at the outlet or key control position of each jet structure 5. Various types such as ball valve, butterfly valve, and needle valve can be selected according to the actual use scenario and performance requirements to achieve the regulation of airflow and pressure.

[0039] By installing a regulating valve on the jet structure 5 and adopting a suitable manual or automatic control method, the flow rate and pressure of the airflow ejected from the jet structure 5 can be precisely adjusted, providing a strong guarantee for the stable operation and efficient granulation of the fluidized bed granulation device.

[0040] In Embodiment 2, each slotted air hole 221 is tightly connected to a vent pipe 7 via welding, flange connection, or other methods. Furthermore, each vent pipe 7 is equipped with a regulating valve, allowing for individual operation of the airflow channel corresponding to each slotted air hole 221. This enables precise control of the airflow rate and pressure entering the cylinder 1 through the slotted air holes 221. To increase the airflow rate in a specific area, simply increase the opening of the regulating valve on the vent pipe 7 connected to the slotted air hole 221 in that area; conversely, to decrease the airflow rate or pressure, simply decrease the opening of the regulating valve. This optimizes the fluidization state and granulation effect of the material, improving product quality and production efficiency.

[0041] Example 3: This embodiment not only adopts the design of the grooved air hole 221 in Embodiment 2, but also adds the jet structure 5 mentioned in Embodiment 1 to the annular air part 22. Specifically, the air hole 221 on the annular air part 22 is grooved, which forms a uniform and stable airflow isolation layer 42 on the inner wall of the cylinder 1. The isolation layer 42 can effectively reduce the direct contact between particles and the inner wall of the cylinder 1, thereby reducing the possibility of particle adhesion. At the same time, the jet structure 5 configured on the annular air part 22 further enhances the ability to prevent particle adhesion.

[0042] In actual operation, the slotted air hole 221 first plays its role, forming an isolation air layer 42 on the inner wall of the cylinder 1. However, due to the complexity of the cylinder 1 structure and the differences in material properties, some areas of the inner wall of the cylinder 1 may still not completely avoid particle adhesion. At this time, the jet structure 5 starts to work, increasing the pressure in this area to generate a strong airflow impact force, which quickly removes the attached particles, ensuring that the inner wall of the cylinder 1 is always kept clean and avoiding the impact of particle adhesion on granulation quality and equipment performance. In order to achieve precise control of the airflow injected by the air hole 221 and the jet structure 5, this embodiment is also equipped with regulating valves for the air hole 221 and the jet structure 5. Through the independent operation of the regulating valves, the operator can flexibly adjust the airflow rate and pressure of the slotted air hole 221 and the jet structure 5 according to the actual situation of different areas inside the cylinder 1.

[0043] Furthermore, an annular baffle 8 is provided on the perforated plate portion 21. The annular baffle 8 is located on the side of the perforated plate portion 21 facing the fluidizing air chamber 3 and completely surrounds the edge of the perforated plate portion 21. Common methods such as welding and bolt connection are used to ensure that the annular baffle 8 can be firmly fixed on the perforated plate portion 21, so that the annular baffle 8 and the edge of the perforated plate portion 21 are closely fitted, thereby forming a relatively independent sealed space between the two, effectively isolating the perforated plate portion 21 from the annular air portion 22.

[0044] Because the porous plate section 21 and the annular gas section 22 share the same gas source, if they are not isolated from each other, the airflow will interfere with each other during actual operation. This results in uneven distribution of the airflow entering the cylinder 1 through the porous plate section 21 and the annular gas section 22, and also causes the isolation gas layer 42 formed on the inner wall of the cylinder 1 to have varying thicknesses and uneven distribution. On the one hand, particles in some areas may not be fully suspended due to insufficient airflow, leading to accumulation and agglomeration, affecting the quality and uniformity of granulation; on the other hand, particles in other areas may move excessively due to excessive airflow, increasing collisions and wear between particles, which is also detrimental to the stable operation of the granulation process.

[0045] The addition of the annular baffle 8 creates an independent sealed space, preventing airflow interference between the porous plate section 21 and the annular gas section 22, thus ensuring the stability and uniformity of their respective airflows. The porous plate section 21 can stably provide uniform airflow to the granulation area according to design requirements, enabling particles to achieve uniform suspension and stable movement within the granulation area; the annular gas section 22 can also effectively perform its function of forming an isolation gas layer 42, effectively reducing particle adhesion to the inner wall of the cylinder 1, thereby improving the working efficiency and product quality of the entire fluidized bed granulation device.

[0046] To further enhance the effect, instead of just one layer of jet structure 5, multiple layers of jet structures 5 are set in the circumferential direction of the annular air section 22, and they are arranged in an alternating manner. That is, the length of the vent pipe 7 is changed to make the jet structure 5 present in multiple layers. The multiple alternating jet structures 5 can make the airflow form a more uniform and dense distribution in the circumferential direction of the annular air section 22. Each layer of jet structure 5 can spray airflow into the surrounding space from different angles and positions. The airflow of different layers overlaps and complements each other, effectively avoiding the airflow dead zones and uneven distribution problems that may occur with a single layer of jet structure 5.

[0047] To further explain, each layer of the jet structure 5 has a unique elevation angle at its outlet. The elevation angles vary between different layers, potentially increasing sequentially from small to large, or following a specific pattern. For example, the bottommost jet structure 5 has a smaller outlet elevation angle, close to horizontal. As the layers increase, the elevation angle gradually increases, causing the airflow to be ejected upwards at different angles. This allows the airflow to be ejected from different heights and positions within the annular air section 22, achieving omnidirectional airflow coverage in the circumferential direction. Compared to single-layer or neatly arranged jet structures 5, this method avoids airflow dead zones, ensuring a more uniform airflow distribution throughout the granulation area.

[0048] Working principle: The airflow enters the cylinder 1 through the gas distribution plate 2. A portion of the airflow passes through the annular gas section 22, is first precisely guided by the inclined air hole 221 or the jet structure 5, and then enters the slit channel 41 formed by the guide section 4 and the inner wall of the cylinder 1. Finally, it flows longitudinally upward along the wall surface, forming a uniform, stable and controllable isolation gas layer 42 on the inner wall surface of the cylinder 1. This effectively isolates the MOCA particles from the inner wall of the cylinder 1, preventing them from adhering due to softening or melting. At the same time, the change in the inclination angle of the air hole 221 and the close contact between the two adjacent guide sections 4 ensure that the airflow flows closely to the wall surface and covers the entire inner wall of the cylinder 1. With the adjustable slit spacing and independent regulating valve, the phenomenon of wall adhesion is fundamentally eliminated, ensuring uniform suspension and growth of particles in the fluidized bed, and improving granulation quality and yield.

[0049] The above description is only a preferred embodiment of the present invention, but the scope of protection of the present invention is not limited thereto. Any equivalent substitutions or modifications made by those skilled in the art within the scope of the technology disclosed in the present invention, based on the technical solution and inventive concept of the present invention, should be covered within the scope of protection of the present invention.

Claims

1. A fluidized bed granulation device for preventing MOCA crystals from sticking to the wall, comprising a vertically arranged cylinder (1), a feed inlet (11) disposed at the upper part of the cylinder (1), and an exhaust port (12) disposed at the top of the cylinder (1), wherein the cylinder (1) is provided with a gas distribution plate (2) and a fluidizing chamber (3) disposed below the gas distribution plate (2), characterized in that: The gas distribution plate (2) has a central porous plate portion (21) and an annular gas portion (22) surrounding its periphery. The inner wall of the cylinder (1) is fixed with a plurality of longitudinally extending guides (4) along the circumferential direction. Each guide (4) forms a longitudinally penetrating slit channel (41) with an adjustable cross-sectional area between it and the inner wall of the cylinder (1). The lower end of the slit channel (41) is connected to the airflow channel of the annular air section (22). When the airflow enters the slit channel (41) through the annular air section (22) and flows longitudinally, an isolation air layer (42) is formed on the inner wall surface of the cylinder (1) to prevent particle adhesion.

2. The fluidized bed granulation device for preventing MOCA crystals from sticking to the wall as described in claim 1, characterized in that: The surface of the annular air section (22) is provided with a plurality of inclined air holes (221), the outlet end of each air hole (221) faces the inner wall of the cylinder (1), and the inclination angle of the air hole (221) gradually increases along the direction away from the inner wall of the cylinder (1). Multiple air holes (221) are distributed circumferentially along the annular air section (22) and are evenly spaced. Alternatively, when the central arc of each air hole (221) is located on the same circumference, multiple air holes (221) are continuously distributed in a sequence or with overlapping ends, so that the isolation air layer (42) completely covers the inner wall of the cylinder (1).

3. The fluidized bed granulation device for preventing MOCA crystals from sticking to the wall as described in claim 2, characterized in that: The annular air section (22) is provided with a plurality of jet structures (5), the outlet direction of each jet structure (5) is toward the inner wall of the cylinder (1) and inclined upward, and corresponds one-to-one with the corresponding slit channel (41), and the inlet end of each jet structure (5) is connected to the corresponding air hole (221).

4. The fluidized bed granulation device for preventing MOCA crystals from sticking to the wall as described in claim 2, characterized in that: The air hole (221) is groove-shaped, and at least two of the air holes (221) are at different radial distances from the inner wall of the cylinder (1). The width of the air hole (221) gradually decreases along the direction away from the inner wall of the cylinder (1) so that the pressure of the airflow after passing through different air holes (221) into the slit channel (41) is the same.

5. The anti-sticking fluidized bed granulation device for MOCA crystals according to claim 1, characterized in that: The flow guide (4) is fixed to the inner wall of the cylinder (1) by a plurality of connecting bodies (6) arranged at intervals along its longitudinal direction. The end of the flow guide (4) away from the gas distribution plate (2) is provided with a guide (43) extending circumferentially along the cylinder (1). The guide (43) is used to guide the airflow flowing out from the slit channel (41) to flow closely against the inner wall surface of the cylinder (1).

6. The anti-sticking fluidized bed granulation device for MOCA crystals according to claim 5, characterized in that: At least two connectors (6) are provided on each of the flow guides (4). Multiple connectors (6) are longitudinally distributed along the central axis of the flow guide (4), and the cross-sectional area of ​​the connector (6) is smaller than that of the flow guide (4), so that when the airflow passes through the connector (6), it continues to flow in the same direction along both sides of the connector (6).

7. A fluidized bed granulation apparatus for preventing MOCA crystals from sticking to the wall, as described in claim 3 or 4, characterized in that: The guide section (4) is divided into several segments along the height direction of the cylinder (1), and the two adjacent segments are connected end to end; in the circumferential direction of the cylinder (1), multiple guide sections (4) are distributed at intervals, or adjacent guide sections (4) are attached to each other.

8. A fluidized bed granulation apparatus for preventing MOCA crystals from sticking to the wall, as described in claim 3 or 4, characterized in that: A regulating valve is installed on the jet structure (5); the slotted air hole (221) is connected to a vent pipe (7), and a regulating valve is also installed on the vent pipe (7).

9. The fluidized bed granulation device for preventing MOCA crystals from sticking to the wall according to claim 1, characterized in that: The porous plate (21) is provided with an annular baffle (8) on the side facing the fluidizing air chamber (3) and along its edge. The annular baffle (8) separates the porous plate (21) from the annular air chamber (22).

10. The anti-sticking fluidized bed granulation device for MOCA crystals according to claim 3, characterized in that: The jet structure (5) of the annular gas section (22) is arranged in multiple staggered layers in the circumferential direction, and the outlet of each layer of jet structure (5) has a different elevation angle.

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