A devolatilizer and a method for devolatilization using the same

Abstract

The present application proposes a devolatilizer and a method for devolatilization using the devolatilizer, the devolatilizer comprising a devolatilizer tank body; an inverted cone distribution plate arranged in the inner cavity of the devolatilizer tank body, the inner wall of the inverted cone distribution plate forming a first working surface for material to pass through; a conical cap-shaped distribution plate arranged in the inner cavity of the devolatilizer tank body, the outer wall of the conical cap-shaped distribution plate forming a second working surface for material to pass through, wherein the inverted cone distribution plate is arranged adjacent to the conical cap-shaped distribution plate, so that the material passes through the first working surface and the second working surface in sequence or passes through the second working surface and the first working surface in sequence. The devolatilizer has a conical cap-shaped distribution plate and an inverted cone distribution plate, which can expand the surface of the melt, prolong the effective devolatilization time, and improve the devolatilization effect within a wider melt viscosity range and a wider operating elasticity range.

Description

Technical Field

[0001] The invention belongs to the technical field of polymer flash devolatilization and strip devolatilization, and particularly relates to a devolatilizer and a method for performing devolatilization using the same. Background Art

[0002] In polymer production, the output from the reactor usually contains low molecular weight raw materials, solvents, by-products, etc. (collectively referred to as "volatiles") in addition to the polymer product. The volatiles need to be removed from the reaction liquid to below an acceptable residual amount in order to obtain a qualified polymer product. This process is called "polymer devolatilization."

[0003] The devolatilization process of polymers can generally be divided into three stages: flash devolatilization, bubbling devolatilization, and diffusion devolatilization. As the volatile content decreases, the viscosity of the devolatilization system increases, and it is difficult for volatile bubbles and molecules to diffuse. In some cases, it is even necessary to use dynamic devolatilization equipment (such as screw extruders and horizontal disc stirring devolatilizers) for surface renewal to reduce the residual volatile content to below the allowable value. However, dynamic devolatilization equipment has high cost and high operating costs. Generally, dynamic devolatilization equipment is only used when the static devolatilization equipment is difficult to achieve the devolatilization target value. The static strip devolatilization equipment forms the devolatilization system into thin strips through the internal parts of a special structure, and then relies on gravity to fall to the melt pool at the bottom of the devolatilization tank. Due to the large specific surface area of ​​the thin strips, the removal rate of volatiles during the descent process can be increased. However, the effective devolatilization time of conventional strip devolatilization equipment depends on the time of the thin strip gravity descent process, which is usually short. After the fluid falls into the melt pool, the material is in a piled state and has a high viscosity. The bubble migration speed in the melt pool is slow and the devolatilization effect in the melt pool is very weak.

[0004] Internal components that expand the melt surface and extend the effective devolatilization time remain the key technologies for enhancing the static devolatilization effect. Summary of the invention

[0005] In view of part or all of the above-mentioned technical problems existing in the prior art, a devolatilizer and a method for devolatilization using the same are provided. The devolatilizer has a conical cap-shaped distribution plate and an inverted conical distribution plate, which can expand the surface of the melt within a wider melt viscosity range and a wider operating elasticity range, prolong the effective devolatilization time, and improve the devolatilization effect.

[0006] According to one aspect of the present invention, the proposed technical solution is:

[0007] A devolatilizer, comprising:

[0008] Devolatilizer tank,

[0009] An inverted cone-shaped distribution plate is arranged in the inner cavity of the devolatilizer tank, and the inner wall of the inverted cone-shaped distribution plate forms a first working surface for materials to pass through.

[0010] A conical hat-shaped distribution plate is arranged in the inner cavity of the devolatilizer tank, and the outer wall of the conical hat-shaped distribution plate forms a second working surface for materials to pass through.

[0011] The inverted cone-shaped distribution plate is arranged adjacent to the conical hat-shaped distribution plate, so that the material passes through the first working surface and the second working surface in sequence or passes through the second working surface and the first working surface in sequence.

[0012] In one embodiment, a plurality of the inverted cone-shaped distribution plates and the cone-hat-shaped distribution plates are arranged in an interval manner in the inner cavity of the devolatilizer tank, and the inverted cone-shaped distribution plate at the uppermost end is used to receive the material supplied by the feed distributor, and the feed distributor comprises:

[0013] The material inlet pipe is connected to the external material source.

[0014] A feed pipe is connectedly arranged at the end of the incoming feed pipe. The feed pipes are multiple and evenly distributed circumferentially at the upper end of the uppermost inverted conical distribution plate to supply materials to the edge of the inverted conical distribution plate.

[0015] In one embodiment, in a direction from top to bottom, the cone angles of the inverted cone-shaped distribution plate and the cone-hat-shaped distribution plate gradually increase.

[0016] In one embodiment, each of the inverted cone-shaped distribution plates and each of the conical hat-shaped distribution plates are spaced apart from the inner wall of the devolatilizer tank to form a gas channel.

[0017] In one embodiment, a fixing sleeve is sleeved on the outer wall of the inverted cone-shaped distribution plate, and a support leg is arranged between the fixing sleeve and the inner wall of the devolatilizer tank body.

[0018] Or / and, a suspension rod extending axially downward is provided on the top wall of the devolatilizer tank body, and the top of the conical hat-shaped distribution plate is suspended on the suspension rod.

[0019] In one embodiment, both the first working surface and the second working surface are configured with circumferentially distributed step teeth.

[0020] In one embodiment, heating pipes are coiled on the outer wall of the inverted cone-shaped distribution plate and on the inner wall of the cone-hat-shaped distribution plate.

[0021] In one embodiment, a blowing gas distributor is further included, wherein the blowing gas distributor comprises:

[0022] Inlet pipe used to connect to external air source,

[0023] An air outlet pipe is arranged at the end of the air inlet pipe, the air outlet pipe is annular and connected to the air inlet pipe, and a plurality of air outlet holes are evenly distributed in the circumferential direction are arranged on the air outlet pipe.

[0024] Wherein, the air outlet pipe is located in the cone-hat-shaped distribution plate at the lowermost end.

[0025] According to another aspect of the present invention, the proposed technical solution is:

[0026] A method for devolatilization using the above-mentioned devolatilizer comprises:

[0027] Step 1: Fill the inner cavity of the devolatilizer tank with devolatilization gas.

[0028] Step 2: supplying polymer material into the inner cavity of the devolatilizer tank, and the polymer material flows from top to bottom through the inverted cone-shaped distribution plate and the cone-hat-shaped distribution plate.

[0029] Step 3: After stopping the supply of polymer material for a period of time, stop charging the devolatilization gas.

[0030] In one embodiment, the devolatilization gas is an inert gas or water vapor, and the temperature of the input devolatilization gas is 0-10° C. higher than the operating temperature, and the pressure of the input devolatilization gas is 0.5-2 bar higher than the operating pressure.

[0031] Compared with the prior art, the advantages of the present invention are: the devolatilizer has a conical hat-shaped distribution plate and an inverted cone-shaped distribution plate, which can expand the surface of the melt within a wider melt viscosity range and a wider operating elasticity range, prolong the effective devolatilization time, and improve the devolatilization effect. BRIEF DESCRIPTION OF THE DRAWINGS

[0032] The preferred embodiments of the present invention will be described in detail below with reference to the accompanying drawings, in which:

[0033] Figure 1 A devolatilizer according to one embodiment of the present invention is schematically shown;

[0034] Figure 2 The hoisting structure of the cone-hat-shaped distribution plate of the devolatilizer according to one embodiment of the present invention is schematically shown;

[0035] Figure 3 The specific structures of the conical hat-shaped distribution plate and the inverted conical distribution plate of the devolatilizer of one embodiment of the present invention are schematically shown;

[0036] Figure 4 The diagram schematically shows the distribution of heating tubes in a devolatilizer according to one embodiment of the present invention.

[0037] In the drawings, the same reference numerals are used for the same components. The drawings are not drawn to scale. DETAILED DESCRIPTION

[0038] In order to make the technical solutions and advantages of the present invention more clearly understood, the exemplary embodiments of the present invention are further described in detail below in conjunction with the accompanying drawings. Obviously, the described embodiments are only part of the embodiments of the present invention, rather than an exhaustive list of all the embodiments. In addition, the embodiments of the present invention and the features in the embodiments can be combined with each other without conflict.

[0039] The present application provides a devolatilizer. Figure 1 and 2 As shown, the devolatilizer includes a devolatilizer tank body 1, an inverted cone-shaped distribution plate 2 and a conical hat-shaped distribution plate 3. Among them, the inverted cone-shaped distribution plate 2 is arranged in the inner cavity of the devolatilizer tank body 1. The inverted cone-shaped distribution plate 2 itself is an inverted cone, and its inner wall forms a first working surface 21 for the material to pass through, so that the material flows through the inverted cone-shaped distribution plate 2, and is guided and distributed by the first working surface 21, and has good film-forming properties, which can help to extend the effective devolatilization time. The conical hat-shaped distribution plate 3 is arranged in the inner cavity of the devolatilizer tank body 1, and itself is a conical hat shape, and its outer wall forms a second working surface 31 for the material to pass through. When the material passes through the conical hat-shaped distribution plate 3, it is guided by the distribution of the second working surface 31, and has good film-forming properties, which can help to extend the effective devolatilization time. In the inner cavity of the devolatilizer tank 1, the inverted cone-shaped distribution plate 2 and the cone-hat-shaped distribution plate 3 are arranged adjacent to each other, so that the material passes through the first working surface 21 and the second working surface 31 in sequence or passes through the second working surface 31 and the first working surface 21 in sequence, so that the melt forms a film on the cone surface multiple times, further prolonging the effective devolatilization time, and the residence time is no longer determined by the height of the devolatilizer. In addition, there is no dead zone in the flow of the material on the cone surface, the residence time is uniform and controllable, and the devolatilization effect is good.

[0040] A plurality of inverted cone-shaped distribution plates 2 and cone-hat-shaped distribution plates 3 are arranged in an intermittent manner in the inner cavity of the devolatilizer tank 1. The distribution plate at the top may be an inverted cone-shaped distribution plate 2 or a cone-hat-shaped distribution plate 3. In addition, the distribution plate at the bottom may be an inverted cone-shaped distribution plate 2 or a cone-hat-shaped distribution plate 3. Thus, the polymer material is guided and distributed through the plurality of distribution plates in sequence, thereby effectively improving the devolatilization effect.

[0041] In one embodiment, one inverted cone-shaped distribution plate 2 and one conical cap-shaped distribution plate 3 form a group, and multiple groups are arranged in the inner cavity of the devolatilizer tank 1, and the inverted cone-shaped distribution plate 2 in one group is arranged upstream, while the conical cap-shaped distribution plate 3 is arranged downstream. The inverted cone-shaped distribution plate 2 at the uppermost end is expanded upward to conveniently receive the material supplied by the feed distributor 4. The conical cap-shaped distribution plate 3 at the lowermost end is convenient for conveying the material into the melt pool 12.

[0042] Specifically, the feed distributor 4 includes an incoming pipe 41 and a lead pipe 42. The incoming pipe 41 is used to communicate with an external polymer material source to transport the material to the inner cavity of the devolatilizer tank 1. The lead pipe 42 is arranged at the end of the incoming pipe 41 and is located at the upper end of the inverted conical distribution plate 2, and is used to transport the material to the inverted conical distribution plate 2. Preferably, there are multiple lead pipes 42, such as 4-60, and they are evenly distributed in the circumferential direction. For example, the lead pipe 42 is constructed as a thin tube with a diameter of 8-20 mm, and the flow resistance of each thin tube is the same. By setting the material through the lead pipe 42, the material melt can be dropped through the fine holes, increasing the specific surface area of ​​the melt, and at the same time, the melt is evenly dropped to the inverted conical distribution plate 2 below it. Further preferably, the outlet of the lead pipe 42 is located at the edge of the inverted conical distribution plate 2, which is used to transport the material to the edge, so as to utilize the guiding and distribution effect of the first working surface 21 to improve the devolatilization effect.

[0043] The lower end of the inverted cone-shaped distribution plate 2 is provided with an opening 22, which is most preferably located at the center of the inverted cone-shaped distribution plate 2 for material dropping. The size of the opening 22 can be adjusted according to the application. For example, the diameter of the opening 22 at the center of the inverted cone-shaped distribution plate 2 is 150 mm, and the material melt flows from the opening 22 to the conical hat-shaped distribution plate 3 below. The material flows out from the end of the feed pipe 42 evenly to the edge of the lower inverted cone-shaped distribution plate 2, forming a uniform falling film flow on the first working surface 21, flowing from the edge to the center. During the falling film flow process, the volatiles in the fluid continuously diffuse to the surface to form a volatile gas phase, which rises through the gas channel 5 between the distribution plate and the inner wall of the devolatilizer tank body 1, and is finally discharged from the gas phase outlet 11 of the devolatilizer tank body 1. The melt flows from the opening 22 to the conical hat-shaped distribution plate 3 below. The opening 22 of the inverted cone distribution plate 2 and the cone-shaped distribution plate 3 are completely symmetrical in the circumferential direction. The fluid forms a uniform falling film flow on the cone-shaped distribution plate 3, flowing from the center to the edge of the cone. The fluid falls from the edge of the cone to the edge of the lower inverted cone distribution plate 2. The diameter of the edge of the cone-shaped distribution plate 3 is more than 50mm smaller than the diameter of the inverted cone distribution plate 2, which is used to completely receive the material melt. Figure 1 In the figure, the material flow direction is indicated by a solid arrow, and the gas flow direction is indicated by a dotted arrow.

[0044] In the direction from top to bottom, the cone angles of the inverted cone distribution plate 2 and the cone-hat-shaped distribution plate 3 gradually increase. In the devolatilization work, in the same devolatilizer, from top to bottom, the melt content gradually increases and the fluidity gradually deteriorates. Through the above-mentioned setting, the larger the cone angle, the more conducive it is for the material to flow, which can adapt to the characteristic that the viscosity of the material gradually increases during the devolatilization process, so that the solution with very low solid content can be concentrated to a solution with very high solid content. For example, the inclination angles of the two distribution plates, the inverted cone distribution plate 2 and the cone-hat-shaped distribution plate 3, can be 5 to 65°. In a specific embodiment, the cone angles of the inverted cone distribution plate 2 and the cone-hat-shaped distribution plate 3 of the upper group are 25°, while the cone angles of the inverted cone distribution plate 2 and the cone-hat-shaped distribution plate 3 of the lower group are 45°.

[0045] Each inverted cone-shaped distribution plate 2 and the cone-hat-shaped distribution plate 3 are spaced apart from the inner wall of the devolatilizer tank 1 to form a gas channel 5. During operation, volatiles continuously overflow from the liquid film to the volatile gas, and the volatile gas rises along the gas channel 5 without relying on the bottom opening 22 of the inverted cone-shaped distribution plate 2 to rise, which can effectively ensure the smooth flow of the rising channel of the volatile gas.

[0046] A fixing sleeve 61 is sleeved on the outer wall of the inverted cone distribution plate 2. A support leg 62 is arranged between the fixing sleeve 61 and the devolatilizer tank body 1. Thus, the position of the inverted cone distribution plate 2 can be limited by the fixing sleeve 61 and the support leg 62, and the structure is simple and easy to implement. A suspension rod 7 extending axially downward is arranged on the top wall of the devolatilizer tank body 1. The top of the cone-shaped hat distribution plate 3 is suspended on the suspension rod 7. For example, the cone-shaped hat distribution plate 3 can be suspended by a detachable joint 71. This hanging arrangement can ensure that the liquid film evenly falls from the edge of the cone-shaped hat distribution plate 3 to the lower inverted cone distribution plate 2 without any blocking components. This support method is conducive to the liquid film flowing evenly to the next layer, so that the residence time of the liquid film flowing in the circumferential direction is uniform.

[0047] Preferably, if Figure 3 As shown, the first working surface 21 and the second working surface 31 are both provided with circumferentially distributed step teeth 23. There are a plurality of step teeth 23. By providing the step teeth 23, the melt surface can be effectively expanded, and the bursting of bubbles on the working surface can be accelerated, thereby facilitating the overflow of volatiles. In a specific embodiment, the inclined surface length a of each step tooth 23 is about 50 mm, and the tooth depth b is about 25 mm.

[0048] In one embodiment, Figure 4 As shown, a heating pipe 8 is arranged in a coiled manner on the outer wall of the inverted cone-shaped distribution plate 2 and the inner wall of the cone-hat-shaped distribution plate 3. The heating pipe 8 is evenly wound to provide the heat required for vaporization of the light component and improve the devolatilization effect.

[0049] In one embodiment, the devolatilizer further includes a blowing gas distributor 9. The blowing gas distributor 9 includes an air inlet pipe 91 for connecting to an external gas source and an air outlet pipe 92 arranged at the end of the air inlet pipe 91. The air outlet pipe 92 is annular and communicated with the air inlet pipe 91. A plurality of circumferentially evenly distributed air outlet holes (not shown in the figure) are arranged on the air outlet pipe 92. For example, the diameter of the air outlet hole can be about 5 mm, and the hole spacing is about 20 mm. The air outlet pipe 92 is located in the cone-shaped distribution plate 3 at the bottom. During operation, after the gas passes through the air inlet pipe 91 and the air outlet pipe 92, it goes out through the air outlet hole, and under the obstruction of the wall of the cone-shaped distribution plate 3, it enters the inner cavity of the devolatilizer tank body 1 and rises. During the gas flow process, the melt surface can be swept to promote the removal of volatiles. The introduction of gas reduces the partial pressure of the solvent in the gas phase and increases the driving force of diffusion devolatilization. At the same time, the flow of gas blows off the gas phase solvent on the surface of the melt, so the devolatilization effect is enhanced. Preferably, the gas may be an inert gas, such as nitrogen, or water vapor.

[0050] The present application also relates to a method for devolatilization using the devolatilizer. Specifically, before conveying the material, the inner cavity of the devolatilizer tank 1 is filled with devolatilization gas, such as nitrogen, through the blowing gas distributor 9.

[0051] After a period of time, for example, 5 minutes, the polymer material is supplied to the inner cavity of the devolatilizer tank 1. After passing through the feed pipe 42 of the feed distributor 4, the polymer falls evenly to the edge of the inverted cone-shaped distribution plate 2, and forms a uniform falling film flow on the first working surface 21, flowing from the edge to the center. After that, it falls to the center of the cone-shaped distribution plate 3 below through the opening 22, and the fluid flows from the center to the edge. In this way, the material can enter the melt pool 12 after passing through multiple groups of inverted cone-shaped distribution plates 2 and cone-shaped distribution plates 3 in sequence.

[0052] After stopping the supply of materials, it takes a while, for example, 5 minutes, to stop supplying the devolatilization gas. Preferably, during operation, the temperature of the input devolatilization gas is 0 to 10°C higher than the operating temperature, and the pressure of the input devolatilization gas is 0.5 to 2 bar higher than the operating pressure. The operating temperature and operating pressure mentioned here are the operating temperature and operating pressure of the devolatilizer during operation, and are constant values ​​for each devolatilization operation.

[0053] Several examples of actual devolatilization operations are given below, in which it is actually demonstrated that the devolatilizer of the present application achieves a better devolatilization effect.

[0054] Example 1

[0055] use Figure 1The devolatilizer shown in the figure removes methylcyclohexane from the polymer solution. The polymer mass fraction in the feed is 70%, the feed viscosity is 100,000 to 500,000 cP, and the feed temperature is about 220°C. After passing through the two sets of inverted cone-shaped distribution plates 2 and cone-shaped distribution plates 3 (on which step teeth 23 and heating tubes 8 are not provided) of the above-mentioned devolatilizer, the solid content of the discharge from the bottom melt pool reaches about 95%. When the bottom nitrogen is stopped, the solid content of the discharge is about 92%. When only one set of inverted cone-shaped distribution plates 2 and cone-shaped distribution plates 3 is retained and the nitrogen is stopped, the material falling film flow time is shortened by about 3 minutes, and the solid content of the discharge can only reach about 85%.

[0056] Example 2

[0057] use Figure 3 The devolatilizer of the embodiment shown. That is, after the inverted cone-shaped distribution plate 2 and the cone-hat-shaped distribution plate 3 in embodiment 1 are processed with the step teeth 23, the inclined surface length of each step tooth 23 is 50 mm and the tooth depth is 25 mm (that is, when the heating tube 8 is not provided). For materials with slightly better fluidity, the fluid surface can be further expanded to improve the devolatilization effect.

[0058] The devolatilizer is used to remove methylcyclohexane from a polymer solution. The polymer mass fraction in the feed is 90%, the feed viscosity is 2000-50000 cP, the feed temperature is about 220°C, and the two sets of inverted cone-shaped distribution plates 2 and cone-shaped distribution plates 3 are used. The residual solvent content in the discharge from the bottom melt pool is reduced to less than 300 ppm. When the inverted cone-shaped distribution plate 2 and cone-shaped distribution plate 3 without step teeth 23 are used, the residual solvent content in the discharge is about 1000 ppm.

[0059] Example 3

[0060] use Figure 4 The devolatilizer of the embodiment shown. That is, a DN20 hot oil pipe is set below the inverted cone-shaped distribution plate 2 and the cone-hat-shaped distribution plate 3 in embodiment 1, and the center spacing of the coils is 50 mm. It can be used to process the working conditions where the solvent content in the feed is high and the heat absorption of the solvent evaporation is large.

[0061] The devolatilizer is used to remove methylcyclohexane from the polymer solution. The polymer mass fraction in the feed is 40%, the feed viscosity is 10,000 cP, and the feed temperature is about 230°C. After entering the devolatilizer, the solvent evaporates and absorbs heat, and the material temperature decreases. Therefore, through theoretical calculation, when the vapor-liquid equilibrium is reached, the temperature in the tank is 170°C and the solid content of the bottom discharge is 85%. By setting a hot oil coil under the distribution plate, the temperature drop caused by the vaporization of the solvent is compensated. After passing through the distribution plate with the hot oil coil, the material temperature of the bottom melt pool reaches 200°C, the solid content reaches more than 90%, and the material viscosity reaches 600,000 cP.

[0062] Although the preferred embodiments of the present invention have been described, those skilled in the art may make additional changes and modifications to these embodiments once they are aware of the basic creative concepts. Therefore, the appended claims are intended to be interpreted as including the preferred embodiments and all changes and / or modifications that fall within the scope of the present invention, and changes and / or modifications made according to the embodiments of the present invention should be included within the scope of protection of the present invention.

Claims

1. A devolatilizer, characterized in that: include: Devolatilizer tank, An inverted cone-shaped distribution plate is arranged in the inner cavity of the devolatilizer tank, and the inner wall of the inverted cone-shaped distribution plate forms a first working surface for materials to pass through. A conical hat-shaped distribution plate is arranged in the inner cavity of the devolatilizer tank, and the outer wall of the conical hat-shaped distribution plate forms a second working surface for materials to pass through. Among them, the inverted cone distribution plate and the cone-hat shaped distribution plate are arranged adjacent to each other, so that the material passes through the first working surface and the second working surface or passes through the second working surface and the first working surface in sequence. A plurality of the inverted cone distribution plates and the cone-hat shaped distribution plates are arranged at intervals in the inner cavity of the devolatilizer tank body, and the inverted cone distribution plate at the uppermost end is used to receive the material supplied by the feed distributor. The feed distributor includes an incoming material pipe connected to an external material source and a lead-in pipe connectedly arranged at the end of the incoming material pipe. The lead-in pipe is a plurality of and circumferentially evenly distributed at the upper end of the inverted cone distribution plate at the uppermost end to supply material to the edge of the inverted cone distribution plate. Each of the inverted cone distribution plates and the cone-hat shaped distribution plates is spaced apart from the inner wall of the devolatilizer tank body to form a gas channel.

2. The devolatilizer according to claim 1, characterized in that In a direction from top to bottom, the cone angles of the inverted cone-shaped distribution plate and the cone-hat-shaped distribution plate gradually increase.

3. The devolatilizer according to claim 1, characterized in that A fixing sleeve is sleeved on the outer wall of the inverted cone-shaped distribution plate, and legs are arranged between the fixing sleeve and the inner wall of the devolatilizer tank body. Or / and, a suspension rod extending axially downward is provided on the top wall of the devolatilizer tank body, and the top of the conical hat-shaped distribution plate is suspended on the suspension rod.

4. The devolatilizer according to any one of claims 1 to 3, characterized in that Step teeth distributed circumferentially are formed on both the first working surface and the second working surface.

5. The devolatilizer according to any one of claims 1 to 3, characterized in that Heating pipes are arranged in a coiled manner on the outer wall of the inverted cone-shaped distribution plate and on the inner wall of the cone-hat-shaped distribution plate.

6. The devolatilizer according to any one of claims 1 to 3, characterized in that Also included is a blowing gas distributor, the blowing gas distributor comprising: Inlet pipe used to connect to external air source, An air outlet pipe is arranged at the end of the air inlet pipe, the air outlet pipe is annular and connected to the air inlet pipe, and a plurality of air outlet holes are evenly distributed in the circumferential direction are arranged on the air outlet pipe. Wherein, the air outlet pipe is located in the cone-hat-shaped distribution plate at the lowermost end.

7. A method for devolatilization using the devolatilizer according to any one of claims 1 to 6, characterized in that: include: Step 1: Fill the inner cavity of the devolatilizer tank with devolatilization gas. Step 2: supplying polymer material into the inner cavity of the devolatilizer tank, and the polymer material flows from top to bottom through the inverted cone-shaped distribution plate and the cone-hat-shaped distribution plate. Step 3: After stopping the supply of polymer material for a period of time, stop charging the devolatilization gas.

8. The method for devolatilization according to claim 7, characterized in that The devolatilization gas is an inert gas or water vapor, and the temperature of the input devolatilization gas is 0-10°C higher than the operating temperature, and the pressure of the input devolatilization gas is 0.5-2 bar higher than the operating pressure.

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