A strip dropping and devolatilization device and devolatilization method

Abstract

The present application belongs to the technical field of polymer devolatilization, and specifically discloses a falling strip, a devolatilization device and a devolatilization method. The falling strip includes at least two plates that are spirally crossed along the length direction, and a plurality of spiral grooves formed by the spiral crossing between the plates; the falling strip also includes at least one dividing line or at least two dividing lines spaced apart along the length direction of the plates, and the dividing lines are arranged circumferentially around the spirally crossed plates and pass through the plates. The devolatilization device includes a sealable devolatilization space, in which at least one falling strip is installed. The devolatilization method includes: after the material to be devolatilized enters the devolatilization space, it flows downward along the groove of the falling strip, flows through the dividing line and is circumferentially cut by the dividing line, and then volatilizes and removes the volatile components. The present application can significantly improve the devolatilization efficiency and solve the problem of difficulty in removing gas inside the fluid.

Description

Technical Field

[0001] The present application relates to the technical field of polymer devolatilization, and in particular to a strip, a devolatilization device and a devolatilization method. Background Art

[0002] To improve devolatilization efficiency, various measures have been adopted in the prior art to improve the strip-type devolatilizer. For example, CN222753210U discloses a strip distribution device and devolatilization system. This system incorporates damping distribution elements within the barrel to increase the material's specific surface area. Furthermore, under pressure, the material is forced through the strip holes, falling in a thread-like pattern, thereby improving devolatilization efficiency.

[0003] CN222238797U discloses a strip-type devolatilizer, which divides the interior of the devolatilizer into a feeding zone and a devolatilization zone by arranging a liquid distributor, and arranges heating conductors distributed in a strip-like manner in the devolatilization zone, so that the material flows along the outer wall of the heating conductor for devolatilization.

[0004] However, existing strip-type devolatilizers still have some technical problems. First, the traditional strip structure is simple, and the material flow pattern on the strip is single, resulting in a limited contact area between the material and the gas phase and low devolatilization efficiency. Second, the existing strip structure is difficult to effectively break the continuity of the material flow, making it difficult to fully release the volatile components inside the material. In addition, for high-viscosity polymers (such as polyolefins), due to their poor fluidity, the dispersion effect on traditional strips is poor, further limiting the devolatilization efficiency. Therefore, there is an urgent need to develop a new strip structure that can increase the contact area between the material and the gas phase, effectively break the continuity of the material flow, and fully release the volatile components inside the material, thereby improving the devolatilization efficiency, especially improving the devolatilization effect for high-viscosity polymers such as polyolefins. Summary of the Invention

[0005] The present application provides a strip-falling, devolatilization device and a devolatilization method to solve the technical problems of low devolatilization efficiency and difficulty in removing internal gas in existing devolatilizers, especially the poor removal effect of volatile components such as unreacted monomers, solvents, additives, by-products and polymers in the polymer production process.

[0006] The present application provides a drop bar comprising at least two plates intersecting in a spiral shape along a length direction, and a plurality of spiral grooves formed by the spiral intersection between the plates;

[0007] The drop strip further includes at least one dividing line or at least two dividing lines spaced apart along the length direction of the plate. The dividing lines are arranged around the circumference of the plate that crosses in a spiral shape and pass through the plate.

[0008] In one embodiment of the present application, the pitch of the spirally crossed plates gradually increases from the beginning to the end along the length direction of the plates.

[0009] In one embodiment of the present application, the drop strip further includes at least two dividing lines spaced apart along the length direction of the plate, and the diameters of the dividing lines gradually decrease from the beginning to the end along the length direction of the plate.

[0010] In one embodiment of the present application, a through hole is opened in the middle of the plate for the dividing line to pass through, and the dividing line passes through the through hole and is arranged around the circumference of the plate in a spiral shape.

[0011] In one embodiment of the present application, a notch-shaped wire groove is opened at the edge of the plate, and the dividing line passes through the wire groove and is arranged around the circumference of the plate in a spiral cross shape, and is fixedly connected to the plate.

[0012] In one embodiment of the present application, the two groove walls of the wire trough are staggered with each other, and the staggered angle of the two groove walls of the wire trough is 0°~20°, and / or the staggered angle of the two groove walls of the wire trough gradually decreases from the beginning to the end along the length direction of the plate.

[0013] In one embodiment of the present application, the dividing line is a silk thread or a silk thread with a coating on its surface, and the coating comprises polytetrafluoroethylene.

[0014] In one embodiment of the present application, the coating further comprises silicon dioxide.

[0015] The present application also provides a devolatilization device, comprising a sealable devolatilization space, wherein at least one falling bar as described above is installed in the devolatilization space, and the falling bar is vertically arranged with its head facing upward and its tail facing downward.

[0016] The present application also provides a devolatilization method, which uses the devolatilization device as described above, including: after the devolatilization material enters the devolatilization space, it flows downward along the groove of the falling strip, flows through the dividing line and is circumferentially cut by the dividing line, and then volatilizes and removes volatile components.

[0017] In one embodiment of the present application, the devolatilization method adopts a pulsed continuous feeding method.

[0018] The beneficial effects of this application are:

[0019] The application of the falling strips in the present application to the devolatilizer is beneficial to improving the devolatilization efficiency and solving the problem of difficulty in removing the gas inside the fluid. It can enable a single devolatilizer to complete the functions that traditionally require two-stage high and low viscosity devolatilizers to achieve. The falling strips have a simple structure and low manufacturing cost.

[0020] The spiral groove design allows the raw material to flow along the groove under the action of gravity, significantly extending the raw material's residence time in the devolatilizer, significantly improving the removal of volatile components compared to traditional devolatilizers. The multiple grooves in the strip also act as distributors, simplifying the equipment structure and reducing production costs.

[0021] The design of the dividing line, which cuts the raw material circumferentially, effectively disrupts the surface tension of low-viscosity fluids, allowing small bubbles of volatile matter to escape from the fluid below the dividing line, enhancing gas-liquid separation efficiency. As the fluid viscosity increases during the devolatilization process, the shear force generated by the dividing line promotes a continuous exchange between the fluid's interior and surface, accelerating the escape of gas from the fluid and resolving the problem of traditional devolatilizers' poor devolatilization performance for high-viscosity materials. Furthermore, the dividing line actively induces the Marangoni effect by cutting the fluid, utilizing surface tension gradients to drive bubble migration, coalescence, and liquid film rupture, achieving efficient degassing.

[0022] The design of gradually increasing pitch from top to bottom can effectively compensate for the problem of reduced fluid fluidity caused by continuous devolatilization, prevent the accumulation of raw materials in the falling strips, and ensure the continuous and stable progress of the devolatilization process.

[0023] The design of the dividing line diameter gradually decreasing from top to bottom helps to enhance the exchange effect between the inner and outer surfaces of the fluid, prevent solute adhesion and blockage, increase the shear rate, and ensure the stability of the devolatilization effect throughout the entire process.

[0024] The staggered design of the upper and lower walls of the trough helps the plates on the lower wall further divide the fluid within the trough, creating a multi-stage cutting effect and further promoting the escape of gas from the fluid. Furthermore, the design of the upper and lower walls of the trough, with the staggered angle gradually decreasing from top to bottom, can adapt to changes in fluid viscosity, allowing the plates on the lower wall of the trough to evenly divide the fluid and improve devolatilization efficiency.

[0025] The application of PTFE coating can effectively prevent corrosion and reduce the deposition and adhesion of solutes on the dividing line, thereby extending the service life of the equipment and reducing maintenance costs.

[0026] In addition, the use of pulsed continuous feeding during devolatilization can ensure the concentration difference and surface tension gradient near the dividing line, ensure the degassing efficiency of the Marangoni effect, and improve the overall devolatilization effect. BRIEF DESCRIPTION OF THE DRAWINGS

[0027] The accompanying drawings are incorporated into and constitute a part of the specification, illustrate embodiments consistent with the present application, and together with the specification, are used to explain the principles of the present application. Obviously, the drawings described below are only some embodiments of the present application. For those of ordinary skill in the art, other drawings can be derived from these drawings without inventive effort.

[0028] In the attached figure:

[0029] Figure 1 This is a schematic diagram of the structure of the drop bar provided in the embodiment of the present application;

[0030] Figure 2 for Figure 1 Enlarged view of point A in the middle;

[0031] Figure 3 This is a front view of the devolatilization device provided in an embodiment of the present application;

[0032] Figure 4 yes Figure 3 AA sectional view of the devolatilization device shown.

[0033] The reference numerals are as follows:

[0034] Devolatilization device 100 , falling strips 110 , plates 111 , grooves 112 , dividing lines 113 , line slots 114 , and devolatilization space 120 . DETAILED DESCRIPTION

[0035] The following describes the embodiments of the present application through specific examples. Those skilled in the art can easily understand other advantages and functions of the present application from the contents disclosed in this specification. The present application can also be implemented or applied through other different specific embodiments. The details in this specification can also be modified or changed based on different viewpoints and applications without departing from the spirit of the present application. The following embodiments and features in the embodiments can be combined with each other without conflict.

[0036] In this application, unless otherwise specified, the term "plurality" means two or more.

[0037] The character " / " indicates that the preceding and following objects are in an "or" relationship. For example, A / B means: A or B.

[0038] 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.

[0039] It should be noted that the illustrations provided in the following embodiments are only schematic illustrations of the basic concept of the present application. The drawings only show components related to the present application and are not drawn according to the number, shape and size of components in actual implementation. In actual implementation, the type, quantity and proportion of each component can be changed at will, and the component layout type may also be more complicated.

[0040] In the following description, a large number of details are discussed to provide a more thorough explanation of the embodiments of the present application. However, it is obvious to those skilled in the art that the embodiments of the present application can be implemented without these specific details. In other embodiments, well-known structures and devices are shown in the form of block diagrams rather than in detail to avoid making the embodiments of the present application difficult to understand.

[0041] See Figure 1 and Figure 2 In one embodiment of the present application, a drop bar 110 is provided. The drop bar 110 includes at least two plates 111 that intersect in a spiral shape along the length direction, and a plurality of spiral grooves 112 formed by the plates 111 intersecting in a spiral shape. The number of the plates 111 is, for example, 4 to 8. Figure 1 falling strip 110 further includes at least one dividing line or at least two dividing lines 113 spaced apart along the length direction of the plate 111, the dividing line surrounding the circumference of the spirally crossed plate 111 is provided, and is provided on the plate 111.

[0042] For example, the strip 110 can be formed by welding the raw materials of the plate 111 into a cross shape, and then twisting it into a spiral cross shape by applying torque to the upper and lower ends to form the spiral groove 112. Then, the dividing lines 113 are inserted one by one on the plate 111 along the length direction of the plate 111.

[0043] Please refer to Figure 3 and Figure 4 The drop bar 110 is vertically mounted in the devolatilization device 100 with its head facing up and its tail facing down. During devolatilization, after the devolatilized material falls onto the drop bar 110, it flows downward along the groove 112, passes through the dividing line 113, and is cut circumferentially by the dividing line 113, volatilizing and removing the volatile components (hereinafter referred to as "volatiles"). During the devolatilization process, the drop bar 110 has the following functions:

[0044] 1. The spiral groove 112 can not only keep the raw material flowing, but also significantly extend the devolatilization time of the material to be devolatilized, thereby improving the volatile matter removal effect.

[0045] 2. In the entire devolatilization process, the dividing line 113 simultaneously plays the following three roles:

[0046] (1) The dividing line 113 can cut the material to be devolatilized in a circumferential direction, and the small bubbles of volatile matter in the fluid leave the fluid along the bottom of the dividing line 113 and are volatilized and removed.

[0047] (2) With the continuous devolatilization, the viscosity of the fluid gradually increases (for example, from 18 Pa·s to 100 Pa·s). Under the action of the shear force of the dividing line 113, the interior and surface of the fluid are exchanged. A small amount of internal gas leaves the fluid along the bottom of the dividing line 113, and a large amount of gas directly leaves the fluid through the form of "interchange between internal and external surfaces". While ensuring fluidity, the higher the fluid viscosity, the stronger this effect.

[0048] (3) Most importantly, the Marangoni effect is actively induced by cutting the fluid through the dividing line 113, and the surface tension gradient is used to drive bubble migration, coalescence and liquid film rupture, thereby achieving efficient degassing. Among them, the main principle steps of degassing using the surface tension gradient are:

[0049] In the first step, the dividing line 113 is cut to generate a surfactant concentration gradient:

[0050] When the fluid flows through the dividing line 113, the surface of the dividing line 113 temporarily adsorbs the surfactant in the fluid (such as solute molecules or impurity ions), resulting in a decrease in the surfactant concentration (C surf ) is lower than the surrounding area.

[0051] According to the Gibbs adsorption equation, the relationship between surface tension (σ) and surfactant concentration is:

[0052]

[0053] Where Γ is the surface adsorption amount, R is the gas constant, T is the temperature, and C is the concentration.

[0054] Cutting area (low C surf ) forms a high surface tension area (σ high ), surrounding fluid (high C surf ) corresponds to low surface tension (σ low ), which produces a radially outward surface tension gradient (∇σ).

[0055] In the second step, Marangoni convection drives bubble migration:

[0056] Marangoni stress induced by surface tension gradient (τ Ma =∇σ) drives the fluid to flow from the low surface tension area (surrounding) to the high surface tension area (cutting interface).

[0057] There are two forces acting on bubbles in shear flow:

[0058] Marangoni migration force: bubbles move toward the high surface tension area (dividing line 113 surface), speed ( ) is estimated by the Young-Goldstein equation:

[0059]

[0060] Where, d b is the bubble diameter, μ is the fluid viscosity, and r is the radial coordinate.

[0061] Shear inertia force (relative to the bubble, it is the shear inertia force of the fluid on the bubble; relative to the fluid, it is the shear force of the dividing line 113 on the fluid): the high shear rate generated by the cutting of the dividing line 113 ( , v is the flow velocity, d wire The diameter of the dividing line 113 is used to stretch and deform the bubbles, thereby increasing the surface area to volume ratio.

[0062] In the third step, the bubbles gather and the liquid film ruptures:

[0063] Coalescing stage: bubbles that migrate to the surface of the dividing line 113 are more likely to contact each other due to the reduced surface energy (high surface tension area). According to Smoluchowski's coalescence theory, the coalescence rate is related to the local shear rate (ẏ) and the bubble concentration (n b ) is proportional to.

[0064] Liquid film rupture exhaust stage: The thickness of the liquid film between bubbles (h) is accelerated by Marangoni convection, and the exhaust time constant (τ drain ∝μ 3 / (σ⋅ΔC)) is significantly shortened. When the liquid film thickness drops to a critical value (h≈10nm~100nm), the van der Waals force dominates the liquid film rupture, completing the degassing of the newly formed tiny bubbles or bubble nuclei.

[0065] The fluid solute concentration (C) and viscosity (μ) are low in the upper half of the strip 110. As the gas is released and volatilized, the solute concentration (C) and viscosity (μ) in the upper half of the strip 110 gradually increase, while the flow velocity (v) gradually decreases. During the top-down devolatilization process, as degassing proceeds, the total amount of surfactant in the fluid gradually decreases, resulting in a gradual decrease in the concentration difference (ΔC), which in turn leads to a gradual decrease in the surface tension gradient (∇σ), ultimately weakening the effectiveness of the Marangoni effect in degassing. For example, at the lower end of the strip 110, when the volatile content of the fluid is less than 10wt%, the Marangoni effect degassing effect is approximately 20% of that at the top of the strip 110.

[0066] In one embodiment of the present application, the pitch of the spirally crossed plates 111 is from the beginning to the end along the length direction of the plates 111 (ie Figure 1The flow rate (V) gradually increases from top to bottom (as shown, and the same applies below). This structure compensates for the reduced fluid flow caused by continuous devolatilization, compensating for the flow rate (v), and preventing material accumulation. More importantly, it ensures a sufficient flow rate to periodically impact solutes adhering to the falling strips 110, ensuring a continuous concentration difference (ΔC) at the dividing line 113 and maintaining the Marangoni effect degassing effect.

[0067] In one embodiment of the present application, the drop bar 110 further includes at least two dividing lines 113 spaced apart along the length of the plate 111. The diameter of the dividing lines 113 gradually decreases along the length of the plate 111. The diameter of the dividing line 113 refers to the diameter of the cross section of the dividing line 113; in other words, the dividing line 113 gradually tapers along the length of the plate 111. This structure has the following advantages: First, in the upper section of the drop bar 110, the fluid velocity (v) is high and the viscosity (μ) is low. Using a relatively large diameter dividing line 113 facilitates the exchange of fluid between the inner and outer surfaces. Second, in the upper section of the drop bar 110, the fluid has a low solute concentration and is less susceptible to solute adhesion. In the lower section of the drop bar 110, the fluid has a high solute concentration and is more susceptible to solute adhesion. Using a smaller diameter dividing line 113 (i.e., a thinner dividing line 113) can help remove adhered solutes, preventing clogging. Third, by reducing the diameter of the dividing line 113, the shear rate (ẏ) can be increased, resulting in a higher shear inertia force, which can shear the bubbles into multiple smaller bubbles, making it easier for the bubbles to escape from the high-viscosity fluid using the Marangoni effect. The shear rate is calculated as follows:

[0068]

[0069] Where v is the flow velocity, d is wire is the diameter of the dividing line 113.

[0070] Therefore, in the upper section of the strip 110, the dividing line 113 is thicker and has a larger diameter, which can generate a medium shear force and preferentially treat large bubbles, such as those with a diameter greater than 100μm, reducing their stability through shear deformation. In the lower section of the strip 110, the dividing line 113 is thinner and has a smaller diameter, which can generate a high shear force and can shear and treat tiny bubbles, such as those with a diameter of 10μm to 100μm, making them easier to escape.

[0071] There are many ways to create the cutting line 113 on the plate 111. In one embodiment of the present application, a through hole (not shown) is provided in the middle of the plate 111 for the cutting line 113 to pass through. The cutting line 113 passes through the through hole and is arranged around the circumference of the plate 111 in a spiral pattern. With this arrangement, during processing, a hole is first punched in the middle of the plate 111, and then the cutting line 113 is inserted into the hole and passed through the plate 111 to form a circle.

[0072] like Figure 2 As shown, in another embodiment of the present application, a notch-shaped wire groove 114 is provided on the edge of the plate 111. The dividing line 113 passes through the wire groove 114 and is arranged around the circumference of the plate 111 in a spiral cross shape, and is fixedly connected to the plate 111. According to this arrangement, during processing, the wire groove 114 is first opened on the outer edge of the plate 111, and then the dividing line 113 is placed inside the wire groove 114. Furthermore, to ensure stability, the dividing line 113 can be fixedly connected to the wire groove 114. The fixed connection method includes but is not limited to welding.

[0073] Furthermore, if Figure 2 As shown, in one embodiment of the present application, the two groove walls of the wire groove 114 are staggered with each other, and the staggered angle of the two groove walls of the wire groove 114 is 0°~20°. Specifically, when looking at the wire groove 114 from a top view, the upper and lower walls of the wire groove 114 are staggered with the bottom of the groove as the center, forming a fan shape. During processing, the wire groove 114 is first opened and then torque is applied, and then the wire groove 114 is fine-tuned in sequence so that the plates 111 on the upper and lower walls of the wire groove 114 are all vertically downward. Such a structure helps to use the plates 111 on the lower wall of the wire groove 114 to divide the fluid in the groove 112 again, and to exchange the inner and outer surfaces of the fluid in the radial direction, which is the same as the effect (2) of the dividing line 113, that is, a large amount of gas directly leaves the fluid through the form of "interchange of inner and outer surfaces". The size design of the staggered angle is mainly related to the fluid flow rate (v) and viscosity (μ), and it is better to control it between 0°~20°.

[0074] Furthermore, in one embodiment of the present application, the staggered angle of the two groove walls of the line groove 114 gradually decreases from the beginning to the end along the length direction of the plate 111. Such a structure is also due to the continuous devolatilization, which causes the fluidity of the fluid in the lower section of the drop bar 110 to decrease, the viscosity (μ) to increase, the flow velocity (v) or the flow velocity after pitch compensation to decrease, and the staggered angle to gradually narrow, so that the plate 111 on the lower wall of the line groove 114 can evenly divide the fluid. Exemplarily, the staggered angle (α) of the two groove walls of all the line grooves 114 on the drop bar 110 is 12°≤α≤0°, that is, the α of the two groove walls of the line grooves 114 distributed from top to bottom on the drop bar 110 gradually decreases from 12° to 0°, the α of the two groove walls of the line groove 114 at the top is 12°, and the α of the two groove walls of the line groove 114 at the bottom is 0°.

[0075] In one embodiment of the present application, dividing line 113 is a wire or a wire coated on its surface. The wire may include, but is not limited to, steel wire, and the coating may be composed of polytetrafluoroethylene (PTFE). PTFE is both corrosion-resistant and forms a high contact angle θ with alkane solvents, approximately 80° to 100°, creating a lyophobic state and reducing solute deposition and adhesion. It should be noted that both PTFE and alkanes are non-polar substances. According to the principle of "like dissolves like," the PTFE-alkane interfacial tension is low, resulting in cosθ approaching 1 and θ approaching 0°, theoretically indicating complete wetting. However, in practice, due to the molecular orientation effect (i.e., the fluorine atoms of PTFE form a dense array on the surface, reducing interaction with the alkane) and the surface roughness amplification principle (i.e., the micron-scale roughness of PTFE induces a Cassie-Baxter state, reducing the effective contact area), the contact angle θ between the PTFE surface and the alkane can reach 80° to 100°. For example, the θ of n-hexane on PTFE is ≈85°.

[0076] Furthermore, in one embodiment of the present application, the coating also comprises silicon dioxide. Microscopically, silicon dioxide creates micron-sized pores on the surface of the dividing line, which not only increases the specific surface area and improves the PTFE adhesion per unit volume, but also enhances liquid repellency (i.e., solvent repellency) by combining with the Cassie state. When the PTFE surface has a micro-nanoscale roughness, the actual contact angle θ satisfies the following relationship:

[0077] cosθ=fs(cosθ+1)-1

[0078] Where fs is the actual solid-liquid contact area fraction.

[0079] For example, for the PTFE-n-hexane system (θ≈85°), fs≈0.2 in the silica system, then θ≈150° (super-liquid-phobic state), which significantly improves the apparent contact angle and further reduces the solute deposition and adhesion. Compared with the uncoated dividing line 113, the adhesion amount is reduced by 87%, which greatly promotes the detachment of bubbles.

[0080] like Figure 3 and Figure 4 As shown, another embodiment of the present application provides a devolatilization device 100, including a sealable devolatilization space 120, in which at least one falling strip 110 is installed, and the falling strip 110 is vertically arranged with its head facing upward and its tail facing downward.

[0081] Furthermore, the drop bar 110 is installed at the upper part of the devolatilization space 120, and an empty space for hanging silk is left between the lower end of the drop bar 110 and the bottom of the devolatilization space 120. Such a design can combine the advantages of the traditional free-fall devolatilizer, that is, for high-viscosity raw materials, they can form silk when dripping from the lower end of the drop bar 110. However, the initial raw material of the devolatilization device 100 of the present application is a low-viscosity raw material, and the function of the traditional two-stage high and low viscosity devolatilizer can be completed in one devolatilizer. The multiple grooves 112 in the drop bar 110 can also act as a distributor to perform secondary flow distribution, such as using Figure 1 As shown in the falling strip 110 , the raw materials on one falling strip 110 will be divided into four wire flows in the wire hanging space.

[0082] In addition, it should be noted that other structures of the devolatilization device 100 can be designed according to conventional or known devolatilizer structures in the art, and this application does not impose any particular limitation.

[0083] Another embodiment of the present application provides a devolatilization method using the devolatilization apparatus 100 described above, comprising: after the material to be devolatilized enters the devolatilization space 120, it flows downward along the grooves 112 of the falling strips 110, passes through the dividing line 113 and is circumferentially cut by the dividing line 113, whereupon the volatile components are volatilized and removed. Preferably, the feeding method is pulsed continuous feeding.

[0084] Pulse continuous feeding is a hybrid feeding method that combines pulse feeding and continuous feeding. Material is continuously added to the devolatilization device 100 at a constant rate for devolatilization. At the same time, the product is continuously discharged to maintain the dynamic balance of the system and achieve continuous feeding. On the basis of continuous feeding, dynamic regulation of the devolatilization process is achieved by periodically pausing the feeding (such as adding in stages).

[0085] Assuming that the feeding interval period of pulsed continuous feeding is t, the design principle of t is to separate and devolatilize the fluid to prevent the formation of continuous flow. t is preferably the time required for the surface of the dividing line 113 of each section of fluid to evaporate completely during the interruption period and to be in a dry state when the solvent on the surface of the dividing line 113 is completely evaporated when each section of fluid passes through the surface of a certain dividing line 113 in the upper half of the falling strip 110. The purpose of this is to solidify a small amount of solute attached to the surface of the dividing line 113 and instantly fall off under the impact of the next section of fluid, thereby ensuring the concentration difference (ΔC) and surface tension gradient (∇σ) near the dividing line 113 and ensuring the degassing efficiency of the Marangoni effect. However, due to the high viscosity of the fluid and the slightly slow flow rate at the dividing line 113 in the lower half of the falling strip 110, the degassing efficiency of the Marangoni effect is inevitably low, so the formation of a continuous flow is allowed and is not considered as a design factor for t.

[0086] In addition, it should be noted that other process details of the devolatilization method can be carried out in a conventional or known manner in the art and are not particularly limited in this application.

[0087] The above embodiments are merely illustrative of the principles and effects of this application and are not intended to limit this application. Anyone skilled in the art may modify or alter the above embodiments without departing from the spirit and scope of this application. Therefore, all equivalent modifications or alterations made by one of ordinary skill in the art without departing from the spirit and technical concepts disclosed in this application shall be covered by the claims of this application.

Claims

1. A falling strip, characterized by: The falling strips include at least two plates that intersect in a spiral shape along the length direction, and a plurality of spiral grooves formed by the plates intersecting in a spiral shape; the pitch of the spirally intersecting plates gradually increases from the beginning to the end along the length direction of the plates; The falling strip also includes at least two dividing lines spaced apart along the length direction of the plate, the dividing lines are arranged around the circumference of the spirally crossed plate and pass through the plate; the diameter of the dividing line gradually decreases from the beginning to the end along the length direction of the plate.

2. The drop strip according to claim 1, characterized in that: A through hole is opened in the middle of the plate for the dividing line to pass through, and the dividing line passes through the through hole and is arranged around the circumference of the plate in a spiral shape.

3. The drop strip according to claim 1, characterized in that: The edge of the plate is provided with a notch-shaped wire groove, and the dividing line passes through the wire groove and is arranged around the circumference of the plate in a spiral cross shape, and is fixedly connected to the plate.

4. The drop strip according to claim 3, characterized in that: The two groove walls of the wire trough are staggered with each other, and the staggered angle of the two groove walls of the wire trough is 0°~20°, and / or the staggered angle of the two groove walls of the wire trough gradually decreases from the beginning to the end along the length direction of the plate.

5. The drop strip according to claim 1, characterized in that: The dividing line is a silk thread or a silk thread with a coating on its surface, and the coating comprises polytetrafluoroethylene.

6. The drop strip according to claim 5, characterized in that: The coating also includes silicon dioxide.

7. A devolatilization device, characterized in that: The devolatilization device comprises a sealed devolatilization space, in which at least one falling strip according to any one of claims 1 to 6 is installed, and the falling strip is vertically arranged with its head facing upward and its tail facing downward.

8. A devolatilization method, characterized in that: The devolatilization method uses the devolatilization device according to claim 7, comprising: After the devolatilization material enters the devolatilization space, it flows downward along the grooves of the falling strips, passes through the dividing line and is circumferentially cut by the dividing line, and then volatilizes and removes volatile components.

9. The devolatilization method according to claim 8, wherein: The feeding method adopts pulse continuous feeding.

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