Film-forming flow supporting element for devolatilization of high-viscosity fluid and devolatilization device

Abstract

The invention relates to the technical field of polymer devolatilization, and particularly discloses a film-forming flow supporting element for high-viscosity fluid devolatilization and a devolatilization device. Wherein the film-forming flow supporting element comprises a vertically arranged supporting circular tube and a convex film-forming devolatilization flow channel which is wound on the peripheral wall surface of the supporting circular tube in a spiral descending manner; a fluid film-forming devolatilization inlet and a fluid film-forming devolatilization outlet are respectively formed in the top and the bottom of the convex film-forming devolatilization runner; the convex film-forming devolatilization runner has at least two spiral periods and continuously extends to the fluid film-forming devolatilization outlet from the fluid film-forming devolatilization inlet; a hollow cavity of the supporting round pipe is a heating medium channel with an upper opening and a lower opening. The convex film-forming devolatilization runner is designed on the outer wall surface of the supporting circular tube, so that high-viscosity fluid can spirally flow around a column in the falling film devolatilization process outside the tube, the film-forming area is increased, the surface is updated at high frequency, and the devolatilization efficiency and the tackifying effect are remarkably improved.

Description

Technical Field

[0001] This invention relates to the field of polymer devolatilization technology, and more particularly to a film-forming flow support element and a devolatilizer for devolatilization of high-viscosity fluids. Background Technology

[0002] Polymers, as key basic materials in modern industry and daily life, are widely used in the production and preparation of synthetic fibers, engineering plastics, rubber products, coatings and adhesives, medical materials, and electronic packaging, serving as the core material basis for the development of industries such as aerospace, transportation, electronics and information, medical and health care, and new energy. Deviation is a crucial unit operation in polymer production, aiming to remove volatile small molecules from the high-viscosity polymer bulk. Its efficiency directly determines the quality and performance of the final product. This process is widely present in several core steps, including melt polycondensation chain growth reactions, spinning solution degassing, and polymer solution demonolysis. As a key step in polymer production, the devolatilization process faces the severe challenge of low mass transfer efficiency in high-viscosity fluids. Melt polycondensation is widely used in the preparation of high-performance polymer materials; however, its reaction process often faces severe challenges in the later stages due to the rapid increase in polymer molecular weight and system viscosity. Deterioration in melt mass transfer becomes the core bottleneck limiting reaction efficiency and product quality.

[0003] To address the common challenges of poor flow controllability and low devolatilization efficiency in high-viscosity polymer fluids, falling film devolatilizers are widely used due to their ability to form a liquid film with a large specific surface area, which facilitates heat and mass transfer. This technology allows high-viscosity polymer fluids to flow in a film-like manner along a vertical wall. Through the synergistic effect of efficient film-forming flow and vacuum, it provides an escape channel for volatiles, offering advantages such as high mass transfer efficiency and short residence time. However, when processing viscosity exceeding 10... 2 When dealing with high-viscosity melts (Pa·s), the inherent limitations of traditional falling film devolatilizers become apparent: the stability of the liquid film flow decreases sharply, making it prone to local thickening, rupture, and even flow interruption, resulting in a severe reduction in the effective mass transfer area. The fundamental reason is that high viscosity leads to a severe lack of surface renewal momentum for the material. The initial liquid film quickly "rigidifies" due to material viscosity, causing a significant increase in boundary layer resistance and a rapid decay of the mass transfer driving force, making it difficult to improve devolatilization efficiency. In other words, current technologies lack an effective mechanism for providing continuous and uniform surface regeneration for high-viscosity fluids.

[0004] In the diffusion-controlled devolatilization stage, the devolatilization efficiency directly depends on the surface renewal rate and the effective mass transfer area. Existing falling film elements with smooth wall structures, smooth inner walls, or simple surface treatments are limited when dealing with viscosities up to 10... 2When the material is at Pa·s or even higher, its function is limited to passively guiding the material flow. It lacks the ability to actively control the liquid film morphology and flow dynamics, and the surface renewal power is seriously insufficient. This results in a limited effective mass transfer area and a serious lack of surface renewal power, which fundamentally restricts the further improvement of devolatilization efficiency.

[0005] Therefore, developing a novel falling film devolatilizer capable of actively stabilizing the liquid film and periodically thinning and renewing its surface is of great significance for the efficient and stable preparation of low-volatile, high-molecular-weight polymers. Summary of the Invention

[0006] To address the aforementioned technical problems, this invention provides a film-forming flow support element for devolatilization of high-viscosity fluids. The invention features an outwardly convex film-forming devolatilization flow channel designed on the outer wall of a supporting circular tube. This allows the high-viscosity fluid to flow in a spiral pattern around the tube during the falling film devolatilization process outside the tube, increasing the film-forming area and frequently renewing the surface, thereby significantly improving devolatilization efficiency and viscosity enhancement. Furthermore, this invention also provides three different devolatilizer structures incorporating the aforementioned film-forming flow support element.

[0007] The specific technical solution of the present invention includes:

[0008] In a first aspect, the present invention provides a film-forming flow support element for the devolatilization of high-viscosity fluids, comprising a vertically arranged support circular tube and a convex film-forming devolatilization channel spirally descending around the outer peripheral wall of the support circular tube. The top and bottom of the convex film-forming devolatilization channel are respectively a fluid film-forming devolatilization inlet and a fluid film-forming devolatilization outlet; the convex film-forming devolatilization channel has at least two spiral cycles, continuously extending from the fluid film-forming devolatilization inlet to the fluid film-forming devolatilization outlet. The hollow cavity of the support circular tube serves as a heat medium channel with openings at the top and bottom.

[0009] The present invention has a spiral outward convex film-forming and devolatilization channel designed on the outer surface of the supporting circular tube. Compared with conventional vertical falling film, when the high viscosity polymer containing volatiles is devolatilized in the film-forming flow support element of the present invention, the fluid can flow around the supporting circular tube in a spiral shape along the outward convex film-forming and devolatilization channel under the action of gravity. This structure can significantly enhance the stability of the liquid film and prevent fluid splashing or flow interruption.

[0010] Preferably, the angle A between the bottom surface of the convex film-forming devolatilization channel and the axis of the supporting circular tube is less than 90°.

[0011] Within the radial section of the supporting circular tube, the gravitational force acting on the mass m of the fluid element can be decomposed into a component force along the helical surface. Among these, the radial constraint force F pointing towards the wall of the supporting circular tube... in It can be represented as F in=mgcos(A). By controlling the included angle A to less than 90°, the edge contraction caused by centrifugal tendency and surface tension can be overcome, forcing the material to always flow closely against the supporting circular tube during the descent process, preventing the material from flowing to the outer edge of the spiral and generating "dripping" or "splashing", thereby ensuring the continuity of the liquid film and the heat transfer efficiency.

[0012] Preferably, the horizontal distance from the edge of the convex film-forming devolatilization channel away from the supporting circular tube to the outer peripheral wall of the supporting circular tube is the width W of the convex film-forming devolatilization channel; the width W of the convex film-forming devolatilization channel remains constant or decreases along the flow direction of the channel. More preferably, the ratio of the width W to the outer diameter d of the supporting circular tube is 0.3-2:1.

[0013] According to the Young-Laplace equation, the characteristic scale of fluid spreading on a solid surface is determined by capillary length, which is the competing mechanism between the effect and gravity. in For surface tension, For density, This is the acceleration due to gravity.

[0014] To ensure that the fluid can be dominated by gravity and spread into a film on the spiral surface, rather than shrinking into a "bead" or "stream" shape due to surface tension, the width W of the flow channel must be significantly greater than the characteristic length.

[0015] Secondly, based on the dual characteristics of "flow rate decay" and "viscosity surge" during the devolatilization process of high-viscosity fluids, this invention selectively employs a gradient contraction of the channel width along the flow direction. In the inlet channel, the material is rich in solvent, with low viscosity but the largest volumetric flow rate. A wider channel is set to match the initial large volumetric flow rate, utilizing the large wetting perimeter to rapidly spread the fluid and maximize the gas-liquid interface area. As a large amount of solvent is rapidly removed, the material's volumetric flow rate significantly decreases. This invention moderately contracts the channel width to match the decrease in flow rate, preventing the liquid film from becoming too thin and rupturing due to an excessively wide channel; ensuring a highly efficient gas-liquid contact surface is maintained in the main flow section. In the outlet channel, the final material viscosity is extremely high, matching the flow rate decay while overcoming the liquid film thickening effect caused by increased viscosity. By maintaining a relatively wide channel, the high-viscosity fluid is forced to be "stretched" into an extremely thin liquid film under the action of the tangential component of gravity, thereby significantly reducing the diffusion resistance of volatiles in the liquid phase and maximizing the devolatilization efficiency.

[0016] Preferably, the single spiral cycle length L of the convex film-forming devolatilization channel is 50-2000 mm. The ratio of the single spiral cycle length L to the outer diameter d of the supporting circular tube is 0.5-10:1.

[0017] By precisely configuring the hydrodynamic inclination angle of the convex film-forming devolatilization channel by adjusting the aforementioned aspect ratio parameters, the system can adapt to the differentiated requirements of non-Newtonian fluids in different viscosity ranges for flow shear force and mass transfer residence time. When the L / d ratio is in the low range, i.e., the helical configuration is relatively dense and gentle, the number of helical turns per unit vertical height increases significantly. This topology greatly stretches the effective streamline length of the fluid, which physically manifests as a significantly extended hydraulic residence time. At the same time, the dense helical curvature enhances the secondary flow effect of the fluid during the flow process, which is beneficial for low-viscosity fluids to achieve deep surface renewal and devolatilization in turbulent conditions. For example, when L / d = 0.5:1, although the axial guide velocity is reduced, an extremely high gas-liquid interface renewal frequency is created, which is particularly suitable for the deep devolatilization stage where mass transfer and diffusion requirements are stringent. When the L / d ratio is in the high range, i.e., the helical configuration is relatively steep and sparse, the helical channel forms a large angle with the horizontal plane. The projection component of the gravity vector in the tangential direction of the channel dominates as the driving force. This design is suitable for extremely high viscosity (>10). 4 The melt with a strength of Pa·s provides a strong axial driving force to effectively overcome its huge yield stress and prevent material from sticking to the wall or clogging the flow channel due to insufficient flow dynamics.

[0018] Preferably, the helix angle B formed by the outwardly convex film-forming devolatilization channel and the axis of the supporting circular tube remains unchanged or decreases along the flow direction of the channel, and the helix angle B is 15-80°.

[0019] In the critical flow conditions, the sole driving force for the high-viscosity fluid sliding down the outwardly convex film-forming and devolatilization channel is the projection of the gravity vector onto the tangent of the helical channel. For a fluid element m, the driving force can be expressed as: Where g is the acceleration due to gravity. The value of the helix angle B avoids the following two extreme rheological risk zones: On the one hand, if the helix angle B exceeds the upper critical value of 80°, the flow channel topology tends to be horizontally coiled. At this time, the tangential driving component of gravity, cos(B), approaches zero, which is insufficient to overcome the huge yield stress and wall viscous resistance of the high-viscosity polymer melt. This can easily induce "rheological retention," leading to local material accumulation, flooding, and degradation and carbonization of heat-sensitive materials due to uncontrolled residence time. On the other hand, if the helix angle B is lower than the lower critical value of 15°, the flow channel configuration approaches a vertical straight line. At this time, although the driving component of gravity is the largest, the fluid will experience a "slip effect," causing the helical guide structure to fail. This results in the loss of the centrifugal shear field and Dean's vortex surface renewal mechanism unique to helical flow, causing the devolatilization mass transfer efficiency to the low level of traditional straight pipe falling film.

[0020] Preferably, the outwardly convex film-forming devolatilization channel is divided into an inlet channel, an intermediate channel, and an outlet channel in sequence along the channel flow direction.

[0021] To achieve better devolatilization, this invention designs the helical angle B of the convex film-forming devolatilization channel to gradually decrease along the fluid flow direction, while the channel width W gradually decreases from top to bottom. Based on the rheological characteristics of high-viscosity fluids, where viscosity increases along the flow path during devolatilization, this invention solves the "flow-film instability" problem in the devolatilization process of high-viscosity materials. In the initial stage of devolatilization, when the high-viscosity fluid flows in the upper helical channel, the viscosity is low but the flow rate is high. The wider channel width W provides sufficient spreading area, and the larger helical angle B prolongs the residence time. In the later stage of devolatilization, when the high-viscosity fluid flows to the lower helical channel, the volumetric flow rate of the material decreases significantly and the viscosity increases sharply as volatiles escape. At this point, if the width remains unchanged, the liquid film will rupture due to excessive thinness, leading to dry wall phenomenon. The gradually decreasing channel width W forces the material to converge when the flow rate decreases, maintaining the film thickness required for effective wetting. At the same time, combined with the gradually decreasing helical angle B, a steeper inclination angle provides a stronger tangential gravitational force, effectively overcoming the flow hysteresis caused by high viscosity. This dual-parameter collaborative adjustment mechanism ensures stable film formation and efficient surface renewal throughout the entire process.

[0022] More preferably, the inlet channel occupies 10-30% of the height of the supporting circular tube, and the helix angle B1 is 60°-80°; the ratio of the width W1 of the channel to the outer diameter d of the supporting circular tube is 1-1.8:1.

[0023] The intermediate flow channel occupies 40-70% of the height of the supporting circular tube, and the helix angle B2 is 30°-60°; the width W2 of the flow channel is 0.6-1.5:1 to the outer diameter d of the supporting circular tube.

[0024] The outlet flow channel occupies 10-30% of the height of the supporting circular tube, and the helix angle B3 is 15°-30°; the ratio of the width W3 of the flow channel to the outer diameter d of the supporting circular tube is 0.3-0.8:1.

[0025] In the inlet channel, a large helical angle combined with a wide helical surface effectively accommodates the large volumetric flow rate of material in the initial stage, preventing liquid overflow. At the same time, the gentle flow channel significantly extends the residence time of low-viscosity fluid, enhancing bubble precipitation and the depth of the initial reaction. The middle channel shrinks in synergy with the helical angle and width, accommodating the reduction in material volume due to the removal of volatiles while maintaining an appropriate thickness and spreading rate of the liquid film on the helical surface. The dual effects of gravity shearing and helical tumbling ensure continuous surface renewal and efficient mass transfer. The outlet channel maximizes the tangential component of gravity through a steep small helical angle, strongly overcoming the flow resistance of high-viscosity melts. At the same time, the channel width is significantly narrowed, forcing the remaining small amount of material to converge towards the center, effectively avoiding liquid film breakage or "dry wall" phenomena caused by flow rate decay, completely eliminating flow dead zones and the risk of thermal degradation, and ensuring the smooth discharge and uniform quality of high-viscosity products.

[0026] Preferably, the bottom surface of the convex film-forming devolatilization channel is a plane or has raised textures or microgrooves along the fluid flow direction.

[0027] The aforementioned raised textures or microgrooves help to guide the downward-flowing liquid film to generate local eddies, thereby further increasing interfacial disturbance and enhancing the surface renewal and mass transfer process.

[0028] More preferably, the angle between the direction of the texture or microgroove and the main spiral direction of the outwardly convex film-forming devolatilization channel is 30°-60°.

[0029] Within the aforementioned angle range, the fluid can be better disturbed, increasing surface renewal.

[0030] Secondly, the present invention provides three devolatilizers with different structures containing the above-mentioned film-forming flow support elements, specifically:

[0031] Option A includes:

[0032] Vertical tower body; the internal cavity of the vertical tower body is divided into, from top to bottom, a heat medium inflow cavity, a heat medium outflow cavity, a high-viscosity material melt cavity, and a film-forming flow devolatilization cavity;

[0033] The top of the vertical tower is provided with a high-viscosity material melt inlet; the high-viscosity material melt inlet is connected to the high-viscosity material melt cavity through a feed pipe that passes through the heat medium inflow cavity and the heat medium outflow cavity; a horizontal film-forming plate is provided between the high-viscosity material melt cavity and the film-forming flow devolatilization cavity;

[0034] The film-forming flow devolatilization chamber is provided with several vertically and parallelly installed film-forming flow support elements; the high-viscosity material melt is introduced from the high-viscosity material melt chamber through the film-forming plate to the fluid film-forming devolatilization inlet of each film-forming flow support element; the side wall of the vertical tower body is provided with a vacuum exhaust port that communicates with the film-forming flow devolatilization chamber, and the film-forming flow devolatilization chamber is in a vacuum state during operation.

[0035] The heat medium inflow chamber is provided with a heat medium inlet; the heat medium outflow chamber is provided with a heat medium outlet; the top of the support tube of the film-forming flow support element penetrates the high-viscosity material melt chamber and the heat medium outflow chamber and extends into the heat medium inflow chamber;

[0036] The film-forming flow support element has an inner sleeve with openings at both ends inside the heat medium channel of the supporting circular tube, and a seal at the bottom of the heat medium channel; a gap is provided between the outer wall of the inner sleeve and the inner wall of the supporting circular tube; the upper end of the inner sleeve passes through the high-viscosity material melt cavity and the heat medium outflow cavity and extends into the heat medium inflow cavity; the heat medium inflow cavity, the inner cavity of the inner sleeve, and the gap are connected to realize that the heat medium flows from the heat medium inflow cavity through the inner cavity of the inner sleeve, the bottom of the supporting circular tube, and the gap to the heat medium outflow cavity;

[0037] Bottom shell; the bottom shell is connected to the bottom of the vertical tower body and communicates with the film-forming flow devolatilization chamber, and the bottom of the bottom shell is provided with a high-viscosity material melt outlet.

[0038] In the devolatilizer of Scheme A above, an inner sleeve is provided inside the supporting circular tube of the film-forming flow support element, constructing a flow path of "inner tube in, outer ring (i.e., gap) out". The heat medium first flows downward through the inner cavity of the inner sleeve, and after reaching the bottom, it flows upward at high speed through the annular gap between the tube wall of the supporting circular tube and the inner sleeve, and after sufficient heat exchange, it is discharged from the top. The design of the annular gap significantly reduces the flow cross section, forcing the heat medium velocity to increase, thereby greatly improving the convective heat transfer coefficient on the tube wall side; at the same time, the heat medium directly scours the tube wall, ensuring an extremely uniform temperature distribution on the wall surface along the tube length, which is particularly suitable for temperature-sensitive and easily thermally degradable polymer systems.

[0039] Option B includes:

[0040] Vertical tower body; the internal cavity of the vertical tower body is divided into, from top to bottom, a heat medium inflow cavity, a heat medium outflow cavity, a high-viscosity material melt cavity, and a film-forming flow devolatilization cavity;

[0041] The top of the vertical tower is provided with a high-viscosity material melt inlet; the high-viscosity material melt inlet is connected to the high-viscosity material melt cavity through a feed pipe that passes through the heat medium inflow cavity and the heat medium outflow cavity; a horizontal film-forming plate is provided between the high-viscosity material melt cavity and the film-forming flow devolatilization cavity;

[0042] The film-forming flow devolatilization chamber is equipped with several vertically installed film-forming flow support elements; the high-viscosity material melt is introduced from the high-viscosity material melt chamber through the film-forming plate to the fluid film-forming devolatilization inlet of each film-forming flow support element; the side wall of the vertical tower body is equipped with a vacuum exhaust port that communicates with the film-forming flow devolatilization chamber, and the film-forming flow devolatilization chamber is in a vacuum state during operation.

[0043] The heat medium inflow chamber is provided with a heat medium inlet; the heat medium outflow chamber is provided with a heat medium outlet; the bottoms of the heat medium channels of every two supporting circular tubes are interconnected (in a U-shape) to form a combination. The top of one of the supporting circular tubes in the combination penetrates the high-viscosity material melt chamber and the heat medium outflow chamber and extends into the heat medium inflow chamber to achieve communication between the top of the heat medium channel and the heat medium inflow chamber. The top of the other supporting circular tube penetrates the high-viscosity material melt chamber and extends into the heat medium outflow chamber to achieve communication between the top of the heat medium channel and the heat medium outflow chamber. Under the above structure, the heat medium reaches the heat medium outflow chamber from the heat medium inflow chamber through the heat medium channels of the two interconnected supporting circular tubes.

[0044] Bottom shell; the bottom shell is connected to the bottom of the vertical tower body and communicates with the film-forming flow devolatilization chamber, and the bottom of the bottom shell is provided with a high-viscosity material melt outlet.

[0045] In the devolatilizer of scheme B, two adjacent film-forming flow support elements are grouped together, and their bottoms are welded together through connecting pipes to form a U-shaped flow channel. The heat medium enters from one support pipe, turns at the bottom, and exits from the other support pipe, forming a series loop of "one in, one out". This scheme has a simpler internal structure and the flow channel is less prone to clogging; the long-path series flow increases the turbulence and residence time of the heat medium in the pipe, which is beneficial to the full utilization of heat, and the U-shaped structure, due to its geometric flexibility, can better eliminate the thermal stress of the tube bundle caused by thermal expansion and contraction.

[0046] Option C includes:

[0047] Vertical tower body; the internal cavity of the vertical tower body is divided into a heat medium inflow cavity, a high viscosity material melt cavity and a film-forming flow devolatilization cavity from top to bottom;

[0048] The top of the vertical tower body is provided with a high-viscosity material melt inlet; the high-viscosity material melt inlet is connected to the high-viscosity material melt cavity through a feed pipe that penetrates the heat medium inflow cavity; a horizontal film-forming plate is provided between the high-viscosity material melt cavity and the film-forming flow devolatilization cavity;

[0049] The film-forming flow devolatilization chamber is provided with several vertically and parallelly installed film-forming flow support elements; the high-viscosity material melt is introduced from the high-viscosity material melt chamber through the film-forming plate to the fluid film-forming devolatilization inlet of each film-forming flow support element; the side wall of the vertical tower body is provided with a vacuum exhaust port communicating with the film-forming flow devolatilization chamber, and the film-forming flow devolatilization chamber is in a vacuum state during operation;

[0050] The heat medium inflow cavity is provided with a heat medium inlet;

[0051] The top of each supporting circular tube extends through the high-viscosity material melt cavity to the heat medium inflow cavity, so that the top of the heat medium channel is connected to the heat medium inflow cavity; the bottom of the heat medium channel of each supporting circular tube is connected to the heat medium outflow pipe; the outlet end of the heat medium outflow pipe extends to the outside of the vertical tower body; under the above structure, the heat medium flows from the heat medium inflow cavity through the heat medium channel of the supporting circular tube to the heat medium outflow pipe.

[0052] Bottom shell; the bottom shell is connected to the bottom of the vertical tower body and communicates with the film-forming flow devolatilization chamber, and the bottom of the bottom shell is provided with a high-viscosity material melt outlet.

[0053] In the devolatilizer of scheme C, the supporting circular tubes are arranged in an array, using a unidirectional straight-through design. The bottom of multiple arrayed supporting circular tubes shares a single heat medium outflow pipe. The heat medium flows from top to bottom through each supporting circular tube and then converges at the bottom into the heat medium outflow pipe for discharge.

[0054] Preferably, the heat medium outlet pipe is arranged horizontally, and the angle between the projection of the axis of the heat medium outlet pipe onto the horizontal plane and the projection of the fluid film-forming and volatilization outlet edge of the outwardly convex film-forming and volatilization channel onto the horizontal plane is 45°-135°.

[0055] When a high-viscosity fluid drips downwards from the end of a spiral flow channel, it forms a "material curtain" with a specific horizontal orientation due to its viscosity. If the axial direction of the heat medium outlet pipe below is parallel to the orientation of this "material curtain," i.e., the angle between them is close to 0°, the high-temperature heat medium outlet pipe will create a large-area obstruction to the falling material, causing the material to adhere to the wall and become stagnant, which in turn triggers the thermal degradation and carbonization of heat-sensitive polymers.

[0056] To address this, the present invention sets the axis of the heat medium outflow pipe and the projection of the fluid film-forming and volatilization outlet edge onto the horizontal plane at a staggered angle of 45°-135° (preferably 90°). This geometric spatial misalignment design allows the lower heat medium outflow pipe to "penetrate" the material's falling path with only a very small contact area, maximizing the vertical discharge space for the high-viscosity melt. This eliminates dead zones in the flow from a physical structure perspective, effectively preventing material accumulation and coking, and ensuring the purity of the final product.

[0057] Compared with the prior art, the beneficial effects of the present invention are:

[0058] (1) The outer wall of the film-forming flow support element of the present invention is provided with an outwardly convex film-forming devolatilization channel. When the high-viscosity fluid flows under gravity, the outwardly convex film-forming devolatilization channel induces the high-viscosity fluid to spread along a spiral path through geometric constraints and channel guidance, forming a continuous and uniform spiral liquid film. This effectively improves the uniformity of liquid film distribution, prolongs the material residence time in the process, and increases the surface renewal frequency of the gas-liquid interface.

[0059] (2) This invention employs a dual synergistic design of a helix angle decreasing from top to bottom and a channel width decreasing from top to bottom. In the inlet channel, a large helix angle and a wide channel are used to support the initial large flow rate and extend the reaction residence time of the low-viscosity fluid. In the outlet channel, considering the exponential increase in material viscosity and the decrease in volumetric flow rate along the flow path, a steep small helix angle is used to maximize the tangential component of gravity to overcome the extremely large flow resistance, while the narrowing of the channel forces the remaining material to converge. This structural design, without the need for powered components, actively adapts to the changes in rheological properties throughout the polymerization process, effectively preventing liquid film breakage (dry wall) caused by flow rate decay and flow stagnation caused by excessive viscosity.

[0060] (3) In the devolatilizer of the present invention, the supporting circular tubes of each film-forming flow support element serve as independent heat medium channels. With the optimized internal circulation or array-type flow channel design, they provide extremely uniform radial heat supply to the liquid film outside the tube. At the same time, each element operates independently in a unified vacuum chamber, and the devolatilization process does not interfere with each other. This coupled structure of "heating inside the tube - falling film outside the tube - vacuuming in space" ensures that the liquid film on each falling film element is in the optimal temperature field and negative pressure field, avoiding the generation of local overheating or cold spots, and ensuring the uniformity of reaction conditions. Attached Figure Description

[0061] Figure 1 This is a schematic diagram of a film-forming flow support element in Embodiment 1 of the present invention;

[0062] Figure 2 This is a schematic diagram of a film-forming flow support element in Embodiment 2 of the present invention;

[0063] Figure 3 This is a schematic diagram of a film-forming flow support element in Embodiment 3 of the present invention;

[0064] Figure 4 This is a schematic diagram of a devolatilizer in Embodiment 4 of the present invention;

[0065] Figure 5 This is a partial connection diagram of the film plate and film-forming flow support element of the devolatilizer in Embodiment 4 of the present invention;

[0066] Figure 6 This is a schematic diagram showing the connection between the film-forming flow support element and the inner sleeve of the devolatilizer in Embodiment 4 of the present invention;

[0067] Figure 7 This is a schematic diagram of a high-viscosity fluid devolatilizer in Embodiment 5 of the present invention;

[0068] Figure 8 This is a schematic diagram of a high-viscosity fluid devolatilizer in Embodiment 6 of the present invention.

[0069] The attached diagram is labeled as follows: 1. Heat medium inlet; 2. Heat medium inflow chamber; 3. Film plate; 4. Shell bolt; 5. Tower jacket heat medium inlet; 6. Vertical tower body; 7. Tower jacket; 8. Supporting round pipe; 9. Bottom shell bolt; 10. Flange; 11. Bottom shell jacket heat medium inlet; 12. Bottom shell jacket; 13. High-viscosity material melt outlet; 14. Bottom shell jacket heat medium outlet; 15. Tower jacket heat medium outlet; 16. Vacuum extraction port; 17. Heat medium outlet; 18. High-viscosity material melt chamber; 19. Heat medium outflow chamber; 20. Feed pipe; 21. High-viscosity material melt inlet; 22. Heat medium outflow pipe; 23. Inner sleeve; 24. Film-forming hole; 31. Outwardly convex film-forming and devolatilization channel; 81. Microgroove; 82. Detailed Implementation

[0070] To enhance understanding of the present invention, the following detailed description of the present invention will be provided using combined embodiments. These embodiments are for illustrative purposes only and do not constitute a limitation on the scope of protection of the present invention.

[0071] Example 1

[0072] A film-forming flow support element for the devolatilization of high-viscosity fluids, such as Figure 1 As shown, it includes a vertically arranged supporting circular tube 8 and a spirally descending, outwardly convex film-forming and volatilization channel 81 wound around the outer peripheral wall of the supporting circular tube. The top and bottom of the outwardly convex film-forming and volatilization channel are the fluid film-forming and volatilization inlet and outlet, respectively; the outwardly convex film-forming and volatilization channel has five spiral cycles, continuously extending from the fluid film-forming and volatilization inlet to the fluid film-forming and volatilization outlet. The hollow cavity of the supporting circular tube serves as a heat medium channel with openings at the top and bottom.

[0073] Specifically, the bottom surface of the convex film-forming devolatilization channel is a plane, with an angle A of 75° between it and the axis of the supporting circular tube. The horizontal distance from the edge of the convex film-forming devolatilization channel away from the supporting circular tube to the outer peripheral wall of the supporting circular tube is the width W of the convex film-forming devolatilization channel, which is 60 mm and remains constant along the flow direction. The outer diameter d of the supporting circular tube is 100 mm, and the length L of a single spiral cycle of the convex film-forming devolatilization channel is 314 mm (the total height of the supporting circular tube is 1570 mm), with a ratio of spiral cycle length L to the outer diameter d of the supporting circular tube of 3.14:1. The spiral angle B of the convex film-forming devolatilization channel remains constant from top to bottom, with a value of 45°.

[0074] Example 2

[0075] A film-forming flow support element for devolatilization of high-viscosity fluids is disclosed in this embodiment. The difference between this embodiment and Embodiment 1 lies in that the helix angle and the width of the flow channel are not fixed values. Figure 2 As shown, compared to Example 1, in this embodiment, the helix angle of the outwardly convex film-forming devolatilization channel decreases in a stepwise manner along the fluid flow direction of the material (from top to bottom) (sequentially including the inlet channel, intermediate channel, and outlet channel), and the width of the channel decreases in a stepwise manner along the fluid flow direction of the material (from top to bottom), thereby achieving progressive control of the fluid flow state. Specifically:

[0076] The outer diameter d of the supporting circular tube for the outwardly convex film-forming devolatilization channel is 60mm, and the effective height of the supporting circular tube is 1760mm.

[0077] The height of the inlet channel is 327 mm, its helix angle B1 is 60°, and the width of the channel W1 is 80 mm.

[0078] The height of the middle channel is 942mm, its helix angle B2 is 45°, and the width of the channel W2 is 60mm.

[0079] The height of the outlet channel is 491 mm, its helix angle B3 is 30°, and the width of the channel W3 is 40 mm.

[0080] In the process of using the film-forming flow support element of this embodiment for devolatilization, in order to adapt to the drastic change in fluid viscosity from low to high, a design is adopted in which the helix angle decreases in stages from top to bottom: the inlet channel has a large angle to stabilize the flow and prevent splashing, the middle channel adjusts the angle to balance the flow velocity, and the outlet channel has a small angle to strongly push and prevent blockage, thereby maintaining a stable thin liquid film throughout the process and achieving efficient and controllable devolatilization.

[0081] Example 3

[0082] A film-forming flow support element for the devolatilization of high-viscosity fluids, such as Figure 3 As shown, the difference between the support element in this embodiment and that in embodiment 1 is that the bottom surface of the outwardly convex film-forming devolatilization channel is provided with microgrooves 82 along the fluid flow direction. The angle between the direction of the microgrooves and the main spiral direction of the outwardly convex film-forming devolatilization channel is 45°.

[0083] Example 4

[0084] A high-viscosity fluid devourer, such as Figure 4 As shown, it includes:

[0085] The vertical tower body 6 has an internal cavity divided from top to bottom into a heat medium inflow cavity 2, a heat medium outflow cavity 20, a high-viscosity material melt cavity 19, and a film-forming flow devolatilization cavity (the high-viscosity material melt cavity and the film-forming flow devolatilization cavity are connected by shell bolts 4). A high-viscosity material melt inlet 22 is located at the top of the vertical tower body; the high-viscosity material melt inlet is connected to the high-viscosity material melt cavity via a feed pipe 21 that passes through the heat medium inflow cavity and the heat medium outflow cavity; a horizontal film-forming plate 3 is provided between the high-viscosity material melt cavity and the film-forming flow devolatilization cavity. Multiple (…) are installed inside the film-forming flow devolatilization cavity. Figure 4Only two vertically and parallelly installed film-forming flow support elements are shown in Example 1. High-viscosity melt is introduced from the high-viscosity melt cavity through film-forming holes 31 distributed on the film-forming plate to the fluid film-forming devolatilization inlet of each film-forming flow support element. The side wall of the vertical tower is provided with a vacuum extraction port 17 communicating with the film-forming flow devolatilization cavity, which is in a vacuum state during operation. The heat medium inflow cavity is provided with a heat medium inlet 1; the heat medium outflow cavity is provided with a heat medium outlet 18; the top of the support tube of the film-forming flow support element penetrates the high-viscosity melt cavity and the heat medium outflow cavity and extends into the heat medium inflow cavity. Specifically, the heat medium channel of the supporting circular tube of the film-forming flow support element is provided with an inner sleeve 24 with openings at the upper and lower ends, and the bottom of the heat medium channel is sealed; a gap is provided between the outer wall of the inner sleeve and the inner wall of the supporting circular tube; the upper end of the inner sleeve passes through the melt cavity of the high-viscosity material and the heat medium outflow cavity and extends into the heat medium inflow cavity; the heat medium inflow cavity, the inner cavity of the inner sleeve and the gap are connected to realize that the heat medium flows from the heat medium inflow cavity through the inner cavity of the inner sleeve, the bottom of the supporting circular tube and the gap to the heat medium outflow cavity.

[0086] Bottom shell 12; The bottom shell is connected to the bottom of the vertical tower body through flange 10 and bottom shell bolts 9 and communicates with the film-forming flow devolatilization chamber. The bottom of the bottom shell is provided with a high-viscosity material melt outlet 14.

[0087] In addition, to maintain the reaction temperature, the vertical tower body is provided with a tower body jacket 7 on the outside and a bottom shell jacket 13 on the outside of the bottom shell, and is respectively equipped with a tower body jacket heat medium inlet 5, a bottom shell jacket heat medium inlet 11, a bottom shell jacket heat medium outlet 15 and a tower body jacket heat medium outlet 16.

[0088] In the devolatilizer of this embodiment, an inner sleeve is provided inside the supporting circular tube of the film-forming flow support element, constructing a flow path of "inner tube in, outer ring (i.e., gap) out". The heat medium first flows downward through the inner cavity of the inner sleeve, and after reaching the bottom, it flows upward at high speed through the annular gap between the tube wall of the supporting circular tube and the inner sleeve, and after sufficient heat exchange, it is discharged from the top. The design of the annular gap significantly reduces the flow cross-section, forcing the heat medium velocity to increase, thereby greatly improving the convective heat transfer coefficient on the tube wall side; at the same time, the heat medium directly scours the tube wall, ensuring an extremely uniform temperature distribution on the wall surface along the tube length, which is particularly suitable for temperature-sensitive and easily thermally degradable polymer systems.

[0089] Example 5

[0090] A high-viscosity fluid devourer, such as Figure 7As shown, the difference from Embodiment 4 is that, in this embodiment, there is no inner sleeve. Instead, the bottoms of the heat medium channels of every two supporting round tubes are interconnected (in a U-shape) as a combination. The top of one of the supporting round tubes in this combination passes through the high-viscosity material melt cavity and the heat medium outlet cavity and extends into the heat medium inlet cavity to achieve communication between the top of the heat medium channel and the heat medium inlet cavity. The top of the other supporting round tube passes through the high-viscosity material melt cavity and extends into the heat medium outlet cavity to achieve communication between the top of the heat medium channel and the heat medium outlet cavity. Under the above structure, the heat medium reaches the heat medium outlet cavity from the heat medium inlet cavity through the heat medium channels of the two interconnected supporting round tubes.

[0091] In the devolatilizer of this embodiment, two adjacent film-forming flow support elements are grouped together, and their bottoms are welded together through connecting pipes to form a U-shaped flow channel. The heat medium enters from one support tube, turns at the bottom, and exits from the other support tube, forming a series loop of "one in and one out". This design has a simpler internal structure and the flow channel is less prone to clogging; the long-path series flow increases the turbulence and residence time of the heat medium in the tube, which is beneficial for the full utilization of heat, and the U-shaped structure, due to its geometric flexibility, can better eliminate the thermal stress of the tube bundle caused by thermal expansion and contraction.

[0092] Example 6

[0093] A high-viscosity fluid devourer, such as Figure 8 As shown, the difference from Embodiment 4 is that in this embodiment, there is no inner sleeve and a heat medium outflow cavity. Instead, the bottom of the heat medium channel of each supporting round tube is connected to the heat medium outflow pipe 23. The outlet end of the heat medium outflow pipe extends to the outside of the vertical tower body. Under the above structure, the heat medium flows from the heat medium inflow cavity through the heat medium channel of the supporting round tube to the heat medium outflow pipe.

[0094] In the devolatilizer of this embodiment, the supporting circular tubes are arranged in an array, adopting a unidirectional straight-through design. The bottom of the multiple arrayed supporting circular tubes shares a single heat medium outflow pipe. The heat medium flows from top to bottom through each supporting circular tube and then converges at the bottom into the heat medium outflow pipe for discharge.

[0095] In addition, the aforementioned heat medium outlet pipe is arranged horizontally, forming a 15° angle with the horizontal direction, and the angle between the projection of the axis of the heat medium outlet pipe onto the horizontal plane and the projection of the fluid film-forming and volatilization outlet edge of the outwardly convex film-forming and volatilization flow channel onto the horizontal plane is 90°.

[0096] The reason for the aforementioned angled design is that when a high-viscosity fluid drips downwards from the end of the spiral flow channel, its viscosity causes it to form a "material curtain" with a specific horizontal orientation. If the axis of the lower heat medium outlet pipe is parallel to the orientation of this "material curtain," i.e., the angle is close to 0°, the high-temperature heat medium outlet pipe will create a large-area obstruction to the falling material, causing material to adhere to the wall and stagnate, thereby triggering thermal degradation and carbonization of the heat-sensitive polymer. Therefore, in this embodiment, the axis of the heat medium outlet pipe and the projection of the fluid film-forming and devolatilization outlet edge onto the horizontal plane are arranged at a 90° cross angle. This geometric spatial misalignment design allows the lower heat medium outlet pipe to "penetrate" the material's falling path with only a very small contact area, maximizing the vertical discharge space for the high-viscosity melt, eliminating dead zones in the flow structure, effectively preventing material accumulation and coking, and ensuring the purity of the final product.

Claims

1. A film forming flow support element for devolatilization of high viscosity fluids, characterized by: The outer convex film-forming devolatilization flow channel is arranged outside the peripheral wall of the supporting circular tube in a spiral descending manner. The top and bottom of the outer convex film-forming devolatilization flow channel are respectively a fluid film-forming devolatilization inlet and a fluid film-forming devolatilization outlet. The outer convex film-forming devolatilization flow channel has at least two spiral periods, and continuously extends from the fluid film-forming devolatilization inlet to the fluid film-forming devolatilization outlet. The hollow cavity of the supporting circular tube is a heat medium passage with an upper opening and a lower opening.

2. The film-forming flow support element of claim 1, wherein: The angle between the bottom surface of the outer convex film-forming devolatilization flow channel and the axis of the supporting circular tube is less than 90 degrees.

3. The film-forming flow supporting element according to claim 1, characterized in that: The horizontal distance from the side edge of the outer convex film-forming devolatilization flow channel away from the supporting circular tube to the peripheral wall of the supporting circular tube is the width of the outer convex film-forming devolatilization flow channel; the width of the outer convex film-forming devolatilization flow channel is constant or decreases along the flow direction of the flow channel; The ratio of the width W to the outer diameter of the supporting circular tube is 0.3-2:

1.

4. The film-forming flow supporting element according to claim 1, characterized in that: The length of a single spiral period of the outer convex film-forming devolatilization flow channel is 50-2000 mm; The ratio of the length of a single spiral period to the outer diameter of the supporting circular tube is 0.5-10:

1.

5. The film forming flow support element of claim 1, wherein: The spiral angle formed by the outer convex film-forming devolatilization flow channel and the axis of the supporting circular tube is constant or decreases along the flow direction of the flow channel, and the spiral angle is 15-80 degrees.

6. The film forming flow support element of claim 5, wherein: The outer convex film-forming devolatilization flow channel is sequentially divided into an inlet flow channel, an intermediate flow channel and an outlet flow channel along the flow direction of the flow channel; The inlet flow channel accounts for 10-30% of the height of the supporting circular tube, the spiral angle is 60-80 degrees, and the ratio of the width of the flow channel to the outer diameter of the supporting circular tube is 1-1.8:1; The intermediate flow channel accounts for 40-70% of the height of the supporting circular tube, the spiral angle is 30-60 degrees, and the ratio of the width of the flow channel to the outer diameter of the supporting circular tube is 0.6-1.5:1; The outlet flow channel accounts for 10-30% of the height of the supporting circular tube, the spiral angle is 15-30 degrees, and the ratio of the width of the flow channel to the outer diameter of the supporting circular tube is 0.3-0.8:

1.

7. A devolatilizer comprising the film-forming flow support element of any one of claims 1-6, wherein: It comprises: A vertical tower body; The inner cavity of the vertical tower body is sequentially divided into a heat medium inflow cavity, a heat medium outflow cavity, a high-viscosity material melt cavity and a film-forming flow devolatilization cavity from top to bottom; The top of the vertical tower body is provided with a high-viscosity material melt inlet; the high-viscosity material melt inlet is communicated with the high-viscosity material melt cavity through a feeding pipe penetrating through the heat medium inflow cavity and the heat medium outflow cavity; a horizontal film distribution plate is arranged between the high-viscosity material melt cavity and the film-forming flow devolatilization cavity; A plurality of vertical and parallel film-forming flow supporting elements are arranged in the film-forming flow devolatilization cavity; the high-viscosity material melt is introduced into the fluid film-forming devolatilization inlet of each film-forming flow supporting element through the film distribution plate from the high-viscosity material melt cavity; the side wall of the vertical tower body is provided with a vacuum air outlet communicated with the film-forming flow devolatilization cavity, and the film-forming flow devolatilization cavity is in a vacuum state in the working state; The heat medium inflow cavity is provided with a heat medium inlet, the heat medium outflow cavity is provided with a heat medium outlet, and the top of the supporting circular tube of the film-forming flow supporting element penetrates through the high-viscosity material melt cavity, the heat medium outflow cavity and extends into the heat medium inflow cavity; The heat medium passage of the supporting circular tube of the film-forming flow supporting element is provided with an inner sleeve pipe with upper and lower end openings, and the bottom of the heat medium passage is provided with a sealing cover; a gap is arranged between the outer wall of the inner sleeve pipe and the inner wall of the supporting circular tube; the upper end of the inner sleeve pipe penetrates the high-viscosity material melt cavity, the heat medium outflow cavity and extends into the heat medium inflow cavity; the heat medium inflow cavity, the inner cavity of the inner sleeve pipe and the gap are communicated to realize the circulation of the heat medium from the heat medium inflow cavity to the heat medium outflow cavity through the inner cavity of the inner sleeve pipe, the bottom of the supporting circular tube and the gap; A bottom shell is connected to the bottom of the vertical tower body and is communicated with the film-forming flow devolatilization cavity, and the bottom of the bottom shell is provided with a high-viscosity material melt outlet.

8. A devolatilizer comprising the film-forming flow support element of any one of claims 1-6, wherein: It comprises: A vertical tower body; The inner cavity of the vertical tower body is sequentially divided into a heat medium inflow cavity, a heat medium outflow cavity, a high-viscosity material melt cavity and a film-forming flow devolatilization cavity from top to bottom; The top of the vertical tower body is provided with a high-viscosity material melt inlet, and the high-viscosity material melt inlet is communicated with the high-viscosity material melt cavity through a feeding pipe penetrating the heat medium inflow cavity and the heat medium outflow cavity; a horizontal film distribution plate is arranged between the high-viscosity material melt cavity and the film-forming flow devolatilization cavity; A plurality of film-forming flow supporting elements are vertically installed in the film-forming flow devolatilization cavity; the high-viscosity material melt is introduced into the fluid film-forming devolatilization inlet of each film-forming flow supporting element from the high-viscosity material melt cavity through the film distribution plate; the side wall of the vertical tower body is provided with a vacuum air outlet communicated with the film-forming flow devolatilization cavity, and the film-forming flow devolatilization cavity is in a vacuum state in the working state; The heat medium inflow cavity is provided with a heat medium inlet, and the heat medium outflow cavity is provided with a heat medium outlet; the bottoms of the heat medium passages of every two supporting circular tubes are communicated with each other as a combination, the top of one of the supporting circular tubes in the combination penetrates the high-viscosity material melt cavity, the heat medium outflow cavity and extends into the heat medium inflow cavity to realize the communication of the top of the heat medium passage with the heat medium inflow cavity, and the top of the other supporting circular tube penetrates the high-viscosity material melt cavity and extends into the heat medium outflow cavity to realize the communication of the top of the heat medium passage with the heat medium outflow cavity; under the above structure, the heat medium circulates from the heat medium inflow cavity to the heat medium outflow cavity through the heat medium passages of the two communicating supporting circular tubes; A bottom shell is connected to the bottom of the vertical tower body and is communicated with the film-forming flow devolatilization cavity, and the bottom of the bottom shell is provided with a high-viscosity material melt outlet.

9. A devolatilizer comprising the film-forming flow support element of any one of claims 1-6, wherein: It comprises: A vertical tower body; The inner cavity of the vertical tower body is sequentially divided into a heat medium inflow cavity, a high-viscosity material melt cavity and a film-forming flow devolatilization cavity from top to bottom; The top of the vertical tower body is provided with a high-viscosity material melt inlet, and the high-viscosity material melt inlet is communicated with the high-viscosity material melt cavity through a feeding pipe penetrating the heat medium inflow cavity; a horizontal film distribution plate is arranged between the high-viscosity material melt cavity and the film-forming flow devolatilization cavity; A plurality of film-forming flow supporting elements are vertically and parallelly installed in the film-forming flow devolatilization cavity; the high-viscosity material melt is introduced into the fluid film-forming devolatilization inlet of each film-forming flow supporting element from the high-viscosity material melt cavity through the film distribution plate; the side wall of the vertical tower body is provided with a vacuum air outlet communicated with the film-forming flow devolatilization cavity, and the film-forming flow devolatilization cavity is in a vacuum state in the working state; The heat medium inflow cavity is provided with a heat medium inlet; The top of each supporting circular tube extends through the high-viscosity material melt cavity to the heat medium inflow cavity to realize the communication of the top of the heat medium channel with the heat medium inflow cavity; the bottom of the heat medium channel of each supporting circular tube communicates with the heat medium outflow pipe; the outlet end of the heat medium outflow pipe extends to the outside of the vertical tower body; under the above structure, the heat medium reaches the heat medium outflow pipe from the heat medium inflow cavity through the heat medium channel of the supporting circular tube; A bottom shell connected to the bottom of the vertical tower body and communicating with the film-forming flow devolatilization cavity, the bottom of the bottom shell being provided with a high-viscosity material melt outlet.

10. The devolatilizer of claim 9, wherein: The heat medium outflow pipe is arranged transversely, and the intersection angle between the projection of the axis of the heat medium outflow pipe on the horizontal plane and the projection of the edge of the fluid film-forming devolatilization outlet of the outward convex film-forming devolatilization flow channel on the horizontal plane is 45°-135°.

Images