Centrifugal devolatilization device and devolatilization method
By designing a centrifugal devolatilizer with gradient radial grooves and annular serrations, the problem of deep devolatilization of high-viscosity heat-sensitive polymers was solved, achieving efficient and compact devolatilization and avoiding material adhesion and thermal degradation.
Patent Information
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- Filing Date
- 2025-12-31
- Publication Date
- 2026-04-03
AI Technical Summary
Existing technologies have insufficient deep devolatilization efficiency when processing high-viscosity heat-sensitive polymers, resulting in material adhesion and clogging, thermal degradation risks, and complex equipment structures with high maintenance costs.
Design a centrifugal devolatilizer that uses a centrifugal disc with radial groove structures such as gradually shallowing straight grooves, gradually narrowing straight grooves, and spiral grooves, and sets annular serrations on the edge of the disc. Combined with an inverted conical cylinder wall, it can achieve self-cleaning sliding of materials and avoid thermal degradation.
It achieves deep devolatilization of high-viscosity polymers, reduces equipment size, avoids material residue and thermal degradation, and improves devolatilization efficiency and equipment compactness.
Smart Images
Figure CN121775465A_ABST
Abstract
Description
Technical Field
[0001] This application relates to the field of chemical technology, specifically to the field of polymer devolatilization technology, and particularly to a centrifugal devolatilizer and devolatilization method suitable for high-viscosity, heat-sensitive polymers. Background Technology
[0002] Polymer devolatilization is a crucial post-processing step in the synthesis and purification of polymer materials. Its purpose is to remove residual monomers, solvents, moisture, and other volatile small molecule impurities from polymer melts or solutions. For high-value-added, high-performance polymers such as polyolefin elastomers (POE), hydrogenated styrene block copolymers (SEBS), and thermoplastic polyurethanes (TPU), the residual volatile content directly determines the product's odor, toxicity, mechanical properties, thermal stability, and optical properties. Therefore, extremely stringent requirements are placed on the depth of devolatilization (typically <100 ppm).
[0003] Currently, there are various devolatilization technologies and equipment available, but they all have significant limitations when processing high-viscosity and heat-sensitive polymer melts (e.g., viscosity ≥ 10000 mPa·s). Existing devolatilization technologies mainly rely on principles such as increasing the mass transfer area, raising the temperature, and reducing the gas phase partial pressure (vacuum).
[0004] For medium- and low-viscosity fluids, de-devouring equipment such as screw extruders, strip devourers, and thin-film evaporators are commonly used. For the treatment of high-viscosity polymers, the following de-devouring equipment is mainly used: High-torque twin-screw extruders still rely on mechanical shearing for devolatilization, and must withstand extremely high energy consumption and huge mechanical loads. The equipment manufacturing and maintenance costs are high, and for heat-sensitive materials such as POE and TPU, they are very prone to molecular chain degradation, cross-linking or yellowing.
[0005] The Buss kneader employs a unique design where the screw simultaneously rotates and reciprocates within the barrel, providing excellent distribution mixing capabilities and self-cleaning functions. While its mixing effect is good, its volatilization efficiency is still limited by the diffusion rate of the melt itself. For applications requiring deep removal of volatiles, extremely long barrels and multiple vacuum sections are often necessary, resulting in exceptionally long equipment, large footprint, and high investment costs.
[0006] The flash tank and screw extruder combined devolatilization unit can remove most of the free solvent, but the subsequent screw extruder relies on thermal history and shear devolatilization. For heat-sensitive POE, long-term high-temperature shearing can easily lead to molecular chain breakage and thermal degradation, resulting in product performance deterioration and failure to meet the production requirements of high-quality products.
[0007] Centrifugal devolatilizers utilize high-speed rotating discs to spin materials into a thin film, increasing the specific surface area and performing devolatilization under high vacuum. However, existing centrifugal devolatilizers have significant drawbacks. The viscosity of the devolatilized polymer increases dramatically (reaching the million cP level), causing it to adhere to the equipment's cylinder wall and preventing it from being discharged smoothly by gravity. Current solutions often employ cylinder wall scrapers or heating methods. The former has a complex mechanical structure, is prone to equipment wear, easily creates dead zones resulting in residue, and has high maintenance costs; the latter exacerbates the risk of thermal degradation and reduces devolatilization efficiency, making it difficult to achieve ppm levels. In addition, traditional centrifugal discs are usually smooth or concentric discs. The smooth surface easily leads to slippage, ultimately resulting in poor devolatilization efficiency and difficulty in achieving deep devolatilization for high-viscosity polymers.
[0008] Therefore, there is an urgent need for a new device and method that can achieve continuous, stable, and efficient deep devolatilization of high-viscosity heat-sensitive polymers without external mechanical scraping or active heating of the cylinder wall, relying solely on the material's own properties and the equipment's geometric design. Summary of the Invention
[0009] In view of the shortcomings of the prior art described above, the purpose of this application is to provide a centrifugal devolatilizer and devolatilization method to solve the problems of insufficient deep devolatilization efficiency of devolatilization devices for high-viscosity heat-sensitive polymers, as well as the problems of material adhesion and blockage, and thermal degradation risks.
[0010] To achieve the above and other related objectives, this application provides a centrifugal devolatilizer, including a cylinder, with a feed inlet and a gas outlet at the top and a discharge outlet at the bottom, and a rotating centrifugal disc inside, with a material inlet at the center of the centrifugal disc, and a guide pipe for conveying material between the feed inlet and the material inlet; The centrifuge disc has several radial grooves, one end of which is connected to the material inlet, and the other end extends radially from the rotation center of the centrifuge disc to the edge. The radial groove is a straight groove, a gradually shallowing straight groove, a gradually narrowing straight groove, a gradually shallowing and gradually narrowing straight groove, a spiral groove, a gradually shallowing spiral groove, a gradually narrowing spiral groove, or a gradually shallowing and gradually narrowing spiral groove. The walls of the straight groove are flat, and the width and depth of the groove are uniform. The gradually shallowing straight groove is a straight groove with a gradually shallowing structure, the gradually narrowing straight groove is a straight groove with a gradually narrowing structure, and the gradually shallowing and gradually narrowing straight groove is a straight groove that has both a gradually shallowing structure and a gradually narrowing structure. The walls of the spiral grooves are arc-shaped, and the width and depth of the grooves are uniform. Several of the spiral grooves are distributed in a spiral shape around the rotation center of the centrifugal disc. The gradually shallowing spiral groove is a spiral groove with a gradually shallowing structure, the gradually narrowing spiral groove is a spiral groove with a gradually narrowing structure, and the gradually shallowing and gradually narrowing spiral groove is a spiral groove that has both a gradually shallowing structure and a gradually narrowing structure. The gradually shallowing structure refers to the groove depth gradually decreasing from the rotation center of the centrifugal disc towards the edge; The tapering structure refers to the groove width gradually decreasing from the rotation center of the centrifugal disc towards the edge.
[0011] Furthermore, the edge of the centrifugal disc is provided with a ring of serrations, with the tips of the serrations facing upwards.
[0012] Furthermore, the teeth of the annular sawtooth are vertical conical structures.
[0013] Furthermore, the height of the annular saw teeth is 1~10mm.
[0014] Furthermore, the distance between two adjacent tooth tips is 6~10mm.
[0015] Furthermore, the depth of the radial groove gradually decreases from the rotation center of the centrifugal disc towards the edge until the bottom of the groove is flush with the bottom of the annular saw teeth.
[0016] Furthermore, the inner wall of the cylinder below the centrifugal disc is configured as an inverted conical wall.
[0017] Furthermore, the distance between the highest point of the inverted conical wall and the centrifugal disc is 250~300mm.
[0018] Furthermore, the cone angle of the inverted conical wall is 70° or more, preferably 70° to 85°.
[0019] Furthermore, the inverted conical wall surface is coated with a smooth coating, or the surfaces of the parts inside the devolatilizer that come into contact with the polymer are coated with a smooth coating.
[0020] Furthermore, the centrifugal devourer also includes a power unit for driving the centrifugal disc to rotate.
[0021] Furthermore, a melt pump is installed at the bottom of the devolatilizer to deliver the melt from the outlet of the devolatilizer.
[0022] Furthermore, the melt pump is a gear pump.
[0023] Furthermore, the melt pump is equipped with a jacket.
[0024] This application also provides a method for devolatilization of polymers, which uses a centrifugal devolatilizer as described above to devolatilize the polymer, including: driving the centrifugal disc to rotate, the polymer material to be devolatilized first enters the material inlet from the feed port along the guide pipe, and then enters the radial groove. In the radial groove, it is accelerated, stretched, and initially devolatilized, and then thrown out from the edge to form polymer filaments, which are then thrown against the inner wall of the cylinder, slide down the wall, and finally discharged from the discharge port; the gas generated during the devolatilization process is discharged from the gas outlet.
[0025] Furthermore, the viscosity of the polymer material to be devolatilized is ≥10000 mPa·s.
[0026] Furthermore, the polymer in the polymer material to be devolatilized is a heat-sensitive polymer.
[0027] Furthermore, during the devaporization process, the centrifugal disc rotates at a speed of 800~1500 rpm.
[0028] Furthermore, during the devolatification process, the temperature of the heat-conducting medium is 80~120℃.
[0029] As described above, the centrifugal devolatilizer and devolatilization method of this application have the following beneficial effects: 1. Through ingenious design of the centrifugal disc, the transformation of material from film formation to active filament formation is realized, allowing high-viscosity polymers to be extremely dispersed into a large number of independent filaments with huge specific surface areas, thereby enabling deep devolatilization of high-viscosity polymers; at the same time, based on the special structural design of the radial grooves on the centrifugal disc, the material can be completely transported to the edge with almost no residue, thus solving the problems of cleaning dead corners and thermal degradation caused by long-term material retention.
[0030] 2. This application provides radial grooves with various structural designs, each with its own advantages: Shallowing structure: As material flows from a deep channel to a shallow channel, the cross-sectional area of the channel decreases, and the flow velocity inevitably increases. This forced acceleration generates a powerful stretching flow within the fluid.
[0031] Gradual narrowing structure: The channel width gradually narrows, further increasing flow resistance and preventing material from spreading to the sides, ensuring that all material is conveyed and accelerated along the main flow direction. It works synergistically with the "shallowing" structure to enhance the stretching effect.
[0032] Helical path: Compared to radial straight channels (i.e., straight channels), helical channels force a longer material flow path. More importantly, as the material flows through the helical path, its flow direction constantly changes, generating a shear flow field that allows the fluid surface to be constantly renewed.
[0033] 3. The outer circumference of the centrifugal disc is equipped with a ring-shaped sawtooth structure. The polymer melt is transported to the edge of the disc through the radial groove and reaches the root of the sawtooth structure. Under the action of strong centrifugal force (which is radially outward), the material has a very high radial movement tendency, which produces a precise guiding and constraining effect on the polymer melt. At this time, the two inclined sides of the sawtooth form a physical guiding channel. When the material is guided to the tip of the sawtooth, a key morphological transformation occurs. Under the drive of centrifugal force, it is continuously stretched by the material behind it, overcoming surface tension and viscoelasticity. Thus, each tooth tip stably and periodically separates a uniform polymer filament.
[0034] 4. The devolatilizer cylinder wall is designed as an integrated inverted conical structure. Through the extreme steep angle design, the material can be gravity-driven to self-clean and slide off, avoiding the adhesion of the polymer to the wall due to the increased viscosity after solvent removal.
[0035] 5. The centrifuge disc is preferably a centrifuge disc with a gradually shallowing and tapering spiral groove and a serrated edge structure. Compared with simple grooves (such as straight grooves) or smooth disc edge designs, the "gradually shallowing and tapering" structure dominates the stretching and thinning, the "spiral" structure dominates the surface renewal, and the serrated disc edge dominates the ultimate filamentation. The combination of these four features ensures that the polymer has been processed into an extremely thin, uniform polymer filament with a continuously renewed surface when it leaves the groove edge. Moreover, the polymer has already completed most of the devolatilization when it begins to fly, and only a shorter flight path is needed to complete the deep devolatilization. Therefore, the radial flight distance between the centrifuge disc and the cylinder wall can be significantly reduced. At the same time, traditional centrifugal devolatilizers need to provide sufficient axial space to stretch and refine the material to complete the devolatilization. However, the centrifuge disc in this application has already drawn the polymer into filaments. The subsequent devolatilization mainly occurs in the flight zone rather than relying on a long path. Therefore, the axial distance of the cylinder can also be shortened, resulting in a more compact overall structure and a smaller equipment size. Attached Figure Description
[0036] The accompanying drawings, which are incorporated in and form part of this specification, illustrate embodiments consistent with this application and, together with the description, serve to explain the principles of this application. It is obvious that the drawings described below are merely some embodiments of this application, and those skilled in the art can obtain other drawings based on these drawings without any inventive effort.
[0037] In the attached diagram: Figure 1 This is a schematic diagram of the centrifugal devolatilizer provided in the embodiments of this application; Figure 2 This is a top view of the centrifugal disc in the centrifugal devolatilizer provided in the embodiments of this application; Figure 3 This is a perspective view of the centrifugal disc in the centrifugal devolatilizer provided in the embodiments of this application.
[0038] The attached figures are labeled as follows: 1. Cylinder body, 11. Inlet, 12. Gas outlet, 13. Outlet, 14. Inverted conical wall, 2. Centrifugal disc, 21. Material inlet, 22. Radial groove, 23. Annular sawtooth, 3. Drive motor, 4. Melt pump. Detailed Implementation
[0039] The following specific examples illustrate the implementation of this application. Those skilled in the art can easily understand other advantages and effects of this application from the content disclosed in this specification. This application can also be implemented or applied through other different specific embodiments. Various details in this specification can also be modified or changed based on different viewpoints and applications without departing from the spirit of this application. In the absence of conflict, the following embodiments and features in the embodiments can be combined with each other.
[0040] In this application, unless otherwise stated, the term "multiple" means two or more.
[0041] The character " / " indicates that the objects before and after it are in an "or" relationship. For example, A / B means: A or B.
[0042] The term "and / or" describes an association between objects, indicating that three relationships can exist. For example, A and / or B means: A or B, or A and B.
[0043] It should be noted that the illustrations provided in the following embodiments are merely schematic representations of the basic concept of this application. The drawings only show components relevant to this application and are not drawn according to the actual number, shape, and size of components in implementation. In actual implementation, the form, quantity, and proportion of each component can be arbitrarily changed, and the component layout may also be more complex. The structures, proportions, sizes, etc., shown in the accompanying drawings are only used to complement the content disclosed in the specification for those skilled in the art to understand and read, and are not intended to limit the conditions under which the present invention can be implemented. Therefore, they have no substantial technical significance. Any modification to the structure, change in the proportional relationship, or adjustment of the size, without affecting the effects and objectives that the present invention can produce, should still fall within the scope of the technical content disclosed in the present invention. At the same time, the terms such as "upper," "lower," "left," "right," "middle," and "one" used in this specification are only for clarity of description and are not intended to limit the scope of the present invention. Changes or adjustments in their relative relationships, without substantially altering the technical content, should also be considered within the scope of the present invention.
[0044] Please see Figure 1One embodiment of this application provides a centrifugal devolatilizer, including a cylinder 1. The height and diameter of the cylinder 1 are designed according to actual needs, for example, the height is 1000~2000mm and the inner diameter is 800~1200mm. The top of the cylinder 1 is provided with a feed inlet 11 and a gas outlet 12, and the bottom is provided with a discharge outlet 13. A rotating centrifugal disc 2 is provided inside, with its center as the rotation center.
[0045] Please combine Figures 1-3 The centrifugal disc 2 has a material inlet 21 at its center, and a guide pipe (not shown in the figure) for conveying materials is provided between the feed inlet 11 and the material inlet 21. The diameter of the centrifugal disc 2 is designed according to the inner diameter of the devolatilizer cylinder 1, for example, 300~800mm; the thickness of the centrifugal disc 2 is for example, 30~50mm, but is not limited to this.
[0046] The upper surface of the centrifugal disc 2 is provided with several radial grooves 22. One end of the radial groove 22 is connected to the material inlet 21, and the other end extends radially from the rotation center of the centrifugal disc 2 to the edge. The radial groove 22 can be a straight groove, a gradually shallowing straight groove, a gradually narrowing straight groove, a gradually shallowing and narrowing straight groove, a spiral groove, a gradually shallowing spiral groove, a gradually narrowing spiral groove, or a gradually shallowing and narrowing spiral groove.
[0047] The walls of the straight groove are flat, and the width and depth of the groove are uniform. The gradually shallowing straight groove is a straight groove with a gradually shallowing structure, the gradually narrowing straight groove is a straight groove with a gradually narrowing structure, and the gradually shallowing and gradually narrowing straight groove is a straight groove with both a gradually shallowing structure and a gradually narrowing structure.
[0048] like Figure 2 and Figure 3 As shown, the walls of the spiral grooves are curved, and the width and depth of the grooves are uniform. Several spiral grooves are distributed in a spiral shape around the rotation center of the centrifugal disk 2. A gradually shallowing spiral groove is a spiral groove with a gradually shallowing structure, a gradually narrowing spiral groove is a spiral groove with a gradually narrowing structure, and a spiral groove with both a gradually shallowing and a gradually narrowing structure is a spiral groove that has both. A gradually shallowing structure means that the groove depth gradually decreases from the rotation center of the centrifugal disk 2 towards the edge, i.e., from deep to shallow; a gradually narrowing structure means that the groove width gradually decreases from the rotation center of the centrifugal disk 2 towards the edge, i.e., from wide to narrow. For example, the depth of the radial groove 22 near the rotation center of the centrifugal disk 2 is 2~5mm, gradually decreasing to 0mm towards the edge; the width of the radial groove 22 near the rotation center of the centrifugal disk 2 is 8~14mm, gradually decreasing to 6~10mm towards the edge.
[0049] The devolatilization process using the centrifugal devolatilizer provided in the above embodiments of this application is as follows: The polymer material to be devolatilized enters the center of the high-speed rotating centrifugal disc 2 from the feed inlet 11. After being accelerated, stretched, and initially devolatilized in the radial groove 22, it is thrown out from the edge, forming a large number of extremely fine polymer filaments. These filaments fly along a spiral trajectory in the huge flight devolatilization zone. Under the multiple effects of centrifugal force, acceleration, and gravity, they impact the cylinder wall with significantly reduced kinetic energy. Their shape immediately changes from point-like to semi-solid tough filaments, which can slide down the wall by their own gravity and are then discharged from the discharge outlet 13. The solvent and small molecule impurities in the polymer material to be devolatilized are converted into gas and discharged from the top gas outlet 12.
[0050] By cleverly designing the centrifugal disc 2, the transformation of material from film formation to active filament formation is realized, allowing high-viscosity polymers to be extremely dispersed into a large number of independent filaments with huge specific surface areas, thereby enabling deep devolatilization of high-viscosity polymers; at the same time, based on the special structural design of the radial groove 22 on the centrifugal disc 2, the material can be completely transported to the edge with almost no residue, thus solving the problems of cleaning dead corners and thermal degradation caused by long-term material retention.
[0051] The radial groove 22 has several structural designs, and the advantages of each structure are as follows: Shallowing structure: As material flows from a deep channel to a shallow channel, the cross-sectional area of the channel decreases, and the flow velocity inevitably increases. This forced acceleration generates a powerful stretching flow within the fluid.
[0052] Gradual narrowing structure: The channel width gradually narrows, further increasing flow resistance and preventing material from spreading to the sides, ensuring that all material is conveyed and accelerated along the main flow direction. It works synergistically with the "shallowing" structure to enhance the stretching effect.
[0053] Helical path: Compared to radial straight channels (i.e., straight channels), helical channels force a longer material flow path. More importantly, as the material flows through the helical path, its flow direction constantly changes, generating a shear flow field that allows the fluid surface to be constantly renewed.
[0054] In some embodiments of this application, the edge of the centrifugal disc 2 is provided with a ring of serrations 23, with the tips of the serrations 23 facing upwards, and a V-shaped groove formed between two adjacent teeth. With the ring of serrations on the outer circumference of the centrifugal disc 2, the polymer melt is conveyed to the edge of the disc via the radial grooves 22, reaching the root of the serrations. Under the action of a strong centrifugal force (directed radially outwards), the material has a very high radial tendency, providing precise guidance and constraint to the polymer melt. At this time, the two inclined sides of the serrations form a physical guiding channel. When the material is guided to the tip of the serration, a crucial morphological transformation occurs. Driven by centrifugal force, it is continuously stretched by the material behind it, overcoming surface tension and viscoelasticity, thereby stably and periodically separating a uniform polymer filament from each tooth tip.
[0055] In some embodiments of this application, the teeth of the annular sawtooth 23 are vertical conical structures with a tooth height of 1~10mm and a distance of 6~10mm between two adjacent tooth tips. This makes the sawtooth more dense and can form extremely fine V-shaped grooves.
[0056] In some embodiments of this application, the depth of the radial groove 22 gradually decreases from the rotation center of the centrifugal disk 2 towards the edge until the bottom of the groove is flush with the bottom of the annular sawtooth 23.
[0057] In some embodiments of this application, the centrifuge disk 2 is a centrifuge disk 2 with a gradually shallowing and tapering spiral groove and a serrated edge structure. Compared with simple grooves (such as straight grooves, gradually shallowing straight grooves, tapering straight grooves, gradually shallowing and tapering straight grooves, spiral grooves, gradually shallowing spiral grooves, tapering spiral grooves, etc.) or smooth disk edge designs, the "gradually shallowing and tapering" structure dominates the stretching and thinning, the "spiral" structure dominates the surface renewal, and the serrated disk edge dominates the ultimate filamentation. The combination of these four features ensures that the polymer has been processed into an extremely thin, uniform polymer filament with a continuously renewed surface when it leaves the edge of the groove. Furthermore, the polymer has already completed most of its devolatilization at the beginning of its flight, and only a shorter flight path is needed to complete the deep devolatilization. Therefore, the radial flight distance between the centrifugal disc 2 and the cylinder wall can be significantly reduced. At the same time, traditional centrifugal devolatilizers need to provide sufficient axial space to stretch and refine the material to complete the devolatilization. However, the centrifugal disc 2 in this application has already drawn the polymer into fine filaments. The subsequent devolatilization mainly occurs in the flight zone rather than relying on a long path. Therefore, the axial distance of the cylinder 1 can also be shortened, resulting in a more compact overall structure and a smaller equipment size.
[0058] In some embodiments of this application, the inner wall of the cylinder 1 below the centrifuge disc 2 is configured as an inverted conical wall 14, forming a large-angle conical collector. The outlet diameter (i.e., the bottom of the cone) of the large-angle conical collector is, for example, DN100~200mm; the distance (i.e., the radial flight distance) between the highest point (i.e., the cone apex) of the inverted conical wall 14 and the upper surface of the centrifuge disc 2 is 250~300mm; the cone angle of the inverted conical wall 14 is 70° or more, preferably 70°-85°. The devolatilizer cylinder wall is designed as an integral inverted conical structure. Through the extremely steep angle design, the component of the material's gravity along the steep wall accelerates the material's flow, achieving self-cleaning sliding and avoiding adhesion to the wall due to the increased polymer viscosity after solvent removal.
[0059] In some embodiments of this application, the inverted conical wall 14 is coated with a smooth coating, or the surfaces of the parts inside the devolatilizer that come into contact with the polymer are coated with a smooth coating; the smooth coating is, for example, a polytetrafluoroethylene (PTFE) coating, but is not limited thereto. Applying a smooth coating prevents material from adhering to the surface due to increased viscosity.
[0060] In some embodiments of this application, the centrifugal devourer further includes a power device for driving the centrifugal disc 2 to rotate, such as a drive motor 3. Figure 1 As shown, in an exemplary embodiment, the drive motor 3 is located above the cylinder 1, the motor drive shaft passes through the cylinder 1 and is connected to the centrifugal disc 2, the material inlet 21 is annular, the drive motor 3 and the annular material inlet 21 are concentrically arranged, and the motor drive shaft adopts a double-end mechanical seal to ensure that the high vacuum in the devolatilizer is not destroyed.
[0061] In some embodiments of this application, a melt pump 4 is installed at the bottom of the devolatilizer to convey the melt from the outlet 13 out of the devolatilizer. The function of the melt pump 4 is to convey the polymer melt out using strong thrust. The melt pump 4 is, for example, a gear pump, but is not limited to this.
[0062] In some embodiments of this application, the melt pump 4 is jacketed. A jacketed melt pump 4 refers to a jacket structure designed into the pump casing or side cover of the melt pump 4. A heat transfer medium (such as heat transfer oil or steam) or coolant is introduced through this structure to achieve precise control of the internal temperature of the pump body. Heating maintains the fluidity of the melt, preventing the material from becoming too viscous due to temperature drop during transport, which could lead to flow difficulties or crystallization. Alternatively, coolant can be introduced when necessary to prevent overheating.
[0063] This application also provides a method for devolatilization of polymers, which uses the centrifugal devolatilizer described above to devolatilize the polymer, including: driving the centrifugal disc 2 to rotate, the polymer material to be devolatilized first enters the material inlet 21 from the feed port 11 along the guide pipe, and then enters the radial groove 22. In the radial groove 22, it is accelerated, stretched and initially devolatilized, and then thrown out from the edge to form polymer filaments, which are then thrown against the inner wall of the cylinder 1, slide down the wall, and finally discharged from the discharge port 13; the gas generated during the devolatilization process is discharged from the gas outlet 12.
[0064] In some embodiments of this application, the viscosity of the polymer material to be devolatilized is ≥10000 mPa·s, and the polymer with this viscosity is a high viscosity polymer.
[0065] In some embodiments of this application, the polymer in the polymer material to be devolatilized is a heat-sensitive polymer, such as POE, TPU, etc., but is not limited to this.
[0066] In some embodiments of this application, during devolatilization, the rotation speed of the centrifugal disc 2 is 800~1500 rpm; the heat transfer medium is heat transfer oil or steam, and the temperature is 80~120°C. Other process details are selected according to the polymer type, viscosity, and actual devolatilization requirements based on existing technologies and conventional methods, and are not particularly limited here.
[0067] The following specific examples illustrate the present invention in detail. It should also be understood that the following examples are only for specific illustrative purposes and should not be construed as limiting the scope of protection of the present invention. Any non-essential improvements and adjustments made by those skilled in the art based on the above description of the present invention are within the scope of protection of the present invention. The specific process parameters, etc., in the following examples are merely examples within a suitable range; that is, those skilled in the art can make appropriate selections within the appropriate range based on the description herein, and are not intended to be limited to the specific values in the examples below.
[0068] Example 1 like Figures 1-3 As shown, this embodiment provides a centrifugal devolatilizer, including a cylinder 1, a centrifugal disc 2, a drive motor 3, and a melt pump 4.
[0069] The cylinder 1 has a feed inlet 11 on one side of the top and a gas outlet 12 on the other side, and a discharge outlet 13 at the bottom. The cylinder 1 has a height of 1500mm and a diameter of 1100mm.
[0070] The cylinder 1 is equipped with a rotating centrifugal disc 2, and a material inlet 21 is located at the center of the centrifugal disc 2. A guide pipe (not shown in the figure) for conveying materials is provided between the feed inlet 11 and the material inlet 21. The drive motor 3 is concentric with the material inlet 21, and the motor drive shaft adopts a double-end mechanical seal to ensure that the high vacuum in the devolatilizer is not broken.
[0071] Centrifuge dish 2 is a centrifuge dish with gradually shallowing and tapering spiral grooves and a serrated edge structure. Centrifuge dish 2 has a diameter of φ500mm and a thickness of 30mm. The radial grooves 22 are gradually shallowing and tapering spiral grooves, with 25 grooves. Figure 2 and Figure 3 For structural schematic diagram only (the number of radial grooves 22 shown is not the actual number), the radial grooves 22 are 10mm wide and 3mm deep near the center, gradually narrowing to 8mm wide and 0mm deep (flush with the bottom of the conical serrations) along the edge. The edge serrations are vertical conical structures with a diameter of about 8mm, and about 200 are closely arranged along the edge. Figure 2 and Figure 3 (This is a schematic diagram; the number of serrations shown in the diagram is not the actual number.) The cone height is 2mm.
[0072] The lower part of the devolatilizer adopts a large-angle conical collector, with the cone apex 300mm from the upper surface of the centrifuge plate 2 (i.e., the radial flight distance is 0.3m), the cone angle is 75°, and the cone bottom outlet diameter is DN150mm.
[0073] The bottom of the devolatilizer is equipped with a jacketed gear pump as the melt pump 4.
[0074] The heat transfer medium is heat transfer oil, and the temperature is controlled at 80~120℃.
[0075] The surfaces of the parts inside the devolatilizer that come into contact with the polymer (including the inner wall of cylinder 1 and the surface of centrifugal disc 2) are all coated with PTFE to prevent the material from adhering to the surface due to increased viscosity.
[0076] As shown in Table 1, POE adhesives of different viscosities were subjected to devolatilization treatment using the centrifugal devolatilizer provided in this embodiment. The devolatilization process is as follows: The POE solution enters the center of the high-speed rotating centrifugal disc 2 through the feed inlet 11. Within the gradually narrowing spiral grooves, it is accelerated, stretched, and undergoes initial devolatilization before being ejected from the serrated edge, forming numerous extremely fine polymer filaments. The high-speed rotating centrifugal disc 2 continuously and uniformly throws these filaments to different heights on the conical wall. These filaments fly along a spiral trajectory within the large flight devolatilization zone, impacting the 75° steep conical wall with significantly reduced kinetic energy under the influence of centrifugal force, acceleration, and gravity. Each filament impacts the conical surface at a single point; upon impact, it transforms into a semi-solid, resilient filament. Due to the extremely smooth and steep conical surface, there is almost no dwell time, so it immediately accelerates downwards along the wall under its own gravity. Finally, stable discharge is achieved through the strong traction of the bottom gear pump. Solvent and small molecule impurity gases exit from the top gas outlet 12.
[0077] The following results were obtained from the test. GPC analysis showed that the molecular weight distribution was consistent with that of the imported product, and there were no signs of thermal degradation.
[0078] Table 1
[0079] As can be seen from Table 1, the centrifugal devolatilizer provided in this embodiment can reduce the solvent content in POE adhesive with a strength of ≥10000mPa·s to <100ppm, achieving a deep devolatilization effect.
[0080] Comparative Example 1 This comparative example provides a centrifugal devolatilizer, which differs from Example 1 in that the centrifugal disc is a smooth centrifugal disc without grooves or serrated edges, and the radial flight distance is 0.5~1m.
[0081] Compared to Comparative Example 1, the radial flight distance of the centrifugal devolatilizer in Example 1 is only 0.3m, which not only saves more than 60% of the equipment space, but also achieves a more uniform and extreme filament drawing effect, thereby improving devolatilization efficiency and achieving a better deep devolatilization effect.
[0082] The above embodiments are merely illustrative of the principles and effects of this application and are not intended to limit this application. Any person skilled in the art can modify or alter the above embodiments without departing from the spirit and scope of this application. Therefore, all equivalent modifications or alterations made by those skilled in the art without departing from the spirit and technical concept disclosed in this application should still be covered by the claims of this application.
Claims
1. A centrifugal devolatilizer, comprising a cylindrical body, wherein the top of the cylindrical body is provided with a feed inlet and a gas outlet, the bottom is provided with a discharge outlet, and a rotating centrifugal disc is provided inside, characterized in that: The centrifugal disc has a material inlet at its center, and a guide pipe for conveying materials is provided between the inlet and the material inlet. The centrifuge disc has several radial grooves, one end of which is connected to the material inlet, and the other end extends radially from the rotation center of the centrifuge disc to the edge. The radial groove is a straight groove, a gradually shallowing straight groove, a gradually narrowing straight groove, a gradually shallowing and gradually narrowing straight groove, a spiral groove, a gradually shallowing spiral groove, a gradually narrowing spiral groove, or a gradually shallowing and gradually narrowing spiral groove. The walls of the straight groove are flat, and the width and depth of the groove are uniform. The gradually shallowing straight groove is a straight groove with a gradually shallowing structure, the gradually narrowing straight groove is a straight groove with a gradually narrowing structure, and the gradually shallowing and gradually narrowing straight groove is a straight groove that has both a gradually shallowing structure and a gradually narrowing structure. The walls of the spiral grooves are arc-shaped, and the width and depth of the grooves are uniform. Several of the spiral grooves are distributed in a spiral shape around the rotation center of the centrifugal disc. The gradually shallowing spiral groove is a spiral groove with a gradually shallowing structure, the gradually narrowing spiral groove is a spiral groove with a gradually narrowing structure, and the gradually shallowing and gradually narrowing spiral groove is a spiral groove that has both a gradually shallowing structure and a gradually narrowing structure. The gradually shallowing structure refers to the groove depth gradually decreasing from the rotation center of the centrifugal disc towards the edge; The tapering structure refers to the groove width gradually decreasing from the rotation center of the centrifugal disc towards the edge.
2. The centrifugal devolatilizer according to claim 1, characterized in that: The edge of the centrifuge disc is provided with a ring of serrations, with the tips of the serrations facing upwards.
3. The centrifugal devolatilizer according to claim 2, characterized in that: The teeth of the annular saw teeth have a vertical conical structure; And / or, the height of the teeth of the annular saw teeth is 1~10mm; And / or, the distance between two adjacent tooth tips is 6~10mm; And / or, the depth of the radial groove gradually decreases from the rotation center of the centrifugal disc toward the edge until the bottom of the groove is flush with the bottom of the annular serration.
4. The centrifugal devolatilizer according to any one of claims 1 to 3, characterized in that: The inner wall of the cylinder below the centrifuge disc is designed as an inverted conical wall.
5. The centrifugal devolatilizer according to claim 4, characterized in that: The distance between the highest point of the inverted conical wall and the centrifugal disk is 250~300mm; And / or, the cone angle of the inverted conical wall is 70° or more; And / or, the inverted conical wall is coated with a smooth coating, or the surfaces of the parts inside the devolatilizer that come into contact with the polymer are coated with a smooth coating.
6. The centrifugal devolatilizer according to claim 1, characterized in that: The centrifugal devourer also includes a power unit for driving the centrifugal disc to rotate.
7. The centrifugal devolatilizer according to claim 1, characterized in that: A melt pump is installed at the bottom of the devolatilizer to deliver the melt from the outlet of the devolatilizer.
8. The centrifugal devolatilizer according to claim 8, characterized in that: The melt pump is a gear pump; And / or, the melt pump is equipped with a jacket.
9. A method for devolatilization of a polymer, characterized in that: The process of devolatilizing polymers using a centrifugal devolatilizer according to any one of claims 1 to 8 includes: The centrifugal disc is driven to rotate. The polymer material to be devolatilized first enters the material inlet from the feed port along the guide pipe, and then enters the radial groove. In the radial groove, it is accelerated, stretched, and initially devolatilized. It is then thrown out from the edge to form polymer filaments, which are then thrown against the inner wall of the cylinder, slide down the wall, and finally exit from the discharge port. The gas generated during the devolatilization process is discharged from the gas outlet.
10. The method for devolatilization of the polymer according to claim 9, characterized in that: The viscosity of the polymer material to be devolatilized is ≥10000 mPa·s; And / or, the polymer in the polymer material to be devolatilized is a heat-sensitive polymer; And / or, during devolatilization, the rotation speed of the centrifuge disc is 800~1500 rpm; And / or, during the devolvation process, the temperature of the heat-conducting medium is 80~120℃.