Polymer solution devolatilization device

Abstract

The invention discloses a polymer solution devolatilization device which comprises a first inlet assembly and a second inlet assembly, a first devolatilization internal part and a second devolatilization internal part are arranged at the outlet end of the first inlet assembly and the outlet end of the second inlet assembly respectively, and a plurality of Venturi type through holes are formed in the outlet faces of the two devolatilization internal parts. A low-viscosity polymer solution is fed from the first inlet assembly, is discharged after promoting removal of volatile components through the first devolatilization internal part, and falls on the outer surface of the second devolatilization internal part to form a film, so that the devolatilization time is prolonged, and the mass transfer area is increased; a high-viscosity polymer solution is fed from the second inlet assembly, and volatile component removal is promoted through the action of the second devolatilization internals. The device can selectively switch feeding according to the viscosity of the polymer solution, is suitable for devolatilization of the polymer solution with a wide viscosity range, can effectively solve the problem of frequent replacement of devolatilization internals during production switching of a plate number with large viscosity difference, ensures long-period stable operation of the device, and is high in devolatilization efficiency, and the obtained polymer is low in volatile component content.

Description

Technical Field

[0001] The invention belongs to the technical field of polymer material production and processing, and relates to the technical field of high molecular polymers. Specifically, the invention relates to a polymer solution devolatilizer. Background Art

[0002] With the widespread application of polymer materials in the automotive industry, photovoltaic components, food packaging and other fields, polymer materials are becoming increasingly important strategic materials. Polyolefin elastomers (POE) are widely used in production and life due to their unique random copolymer structure and excellent physical properties. In the process of preparing POE by solution polymerization, the polymer system after the reaction is terminated usually contains 60-90wt% volatile components, including unreacted ethylene monomer, α-olefin comonomer (such as α-butene, α-hexene, α-octene) and C6-C12 alkane solvents. These residues not only reduce the mechanical properties of the material, but are also likely to release volatile organic compounds (VOCs) that are harmful to the human body during use.

[0003] When the volatile content in the polymer solution is extremely low or the system viscosity is too high, the traditional method usually uses an extruder for devolatilization. However, under high temperature conditions, POE will exhibit significant elastic properties, which not only places stringent requirements on the performance of the extrusion equipment, but also leads to high energy consumption. Taking into account the unique physical properties of POE and its devolatilization process requirements, the falling strip static devolatilizer shows better applicability. This device extrudes POE from the die into the devolatilizer to form falling strips. During the falling process, the volatiles inside the melt are able to migrate to the melt-environment interface and are eventually removed. However, this device still has significant defects: the viscosity range of different grades of polyolefin elastomers is extremely wide, and a single set of equipment is difficult to meet the devolatilization requirements of all grades. When producing different grades of polyolefin elastomers, the internal components of the devolatilization need to be replaced, resulting in production stoppages, which greatly increases production costs. In addition, frequent replacement of internal components will cause parts wear and shorten the service life of the devolatilization device. CN116983691A proposes using a movable orifice plate to make the device suitable for devolatilization of polymers with different viscosities. However, this method is difficult to implement, and the movable orifice plate has safety hazards and a short service life.

[0004] Therefore, there is an urgent need to develop a continuous, safe and efficient devolatilization device and method that is suitable for the devolatilization of polyolefin elastomers with a wide viscosity range, which can meet the quality and safety requirements of high-end polyolefin elastomer products by using only one set of equipment without replacing the internal components. Summary of the Invention

[0005] The present invention aims to provide a polymer solution devolatilizer suitable for devolatilizing polymer solutions with a wide viscosity range. The devolatilizer can effectively solve the problem of frequent replacement of devolatilizing internal parts when switching production grades with large viscosity differences, ensure the long-term stable operation of the device, and has high devolatilization efficiency and low volatile content in the obtained polymer.

[0006] In order to achieve the technical purpose, the present invention provides a polymer solution devolatilizer, characterized in that: the devolatilizer includes a cavity, a first polymer solution inlet component, a second polymer solution inlet component, an exhaust port, a devolatilization aid injection port component and a polymer discharge port; the cavity is provided with a jacket for passing a heat medium, including but not limited to heat transfer oil and high-pressure steam to regulate the temperature in the cavity; the outlet end of the first polymer solution inlet component is provided with a first devolatilization internal component; the first devolatilization internal component is located at the top of the cavity, with its outlet facing downward, and the outlet surface of the first devolatilization internal component is provided with a plurality of Venturi-type vents. hole; the outlet end of the second inlet component of the polymer solution is provided with a second devolatilization internal component, the second devolatilization internal component is located directly below the first devolatilization internal component, its opening is downward and is designed to expand in diameter, the outer surface of the second devolatilization internal component is an inclined surface, and its outlet surface is provided with a plurality of Venturi-type through holes; the devolatilization aid injection port component is arranged on the side of the cavity, and its outlet position is located below the second devolatilization internal component; the polymer discharge port is located at the bottom of the cavity, for discharging the devolatilized polymer; the exhaust port is located at the top of the cavity, for discharging the volatile matter removed from the polymer solution.

[0007] In some preferred embodiments of the present invention, the overall shape of the first devolatilization internal component can be disc-shaped, square or triangular, and its cross-sectional area is 20% to 60% of the cross-sectional area of ​​the cavity. The main part of the cavity is cylindrical, and the upper and lower ends are covered with ellipsoidal cavities. The cross-sectional area of ​​the cavity is the cross-sectional area of ​​the cylindrical main part.

[0008] In some preferred embodiments of the present invention, the overall external shape is a truncated cone with a taper of 30° to 150°; the outer surface of the truncated cone is a smooth surface or is provided with serrated, stepped or wavy protrusions.

[0009] In some preferred embodiments of the present invention, the maximum cross-sectional area of ​​the second devolatilizing internal component is 30% to 80% of the cross-sectional area of ​​the cavity and is 1 to 3 times the cross-sectional area of ​​the first devolatilizing internal component, so that the polymer solution or melt discharged from the first devolatilizing internal component falls on the outer surface of the second devolatilizing internal component to form a film.

[0010] In some preferred embodiments of the present invention, the distance between the first devolatilization internal and the second devolatilization internal is 0.2 to 1 times the diameter of the cavity.

[0011] In some preferred embodiments of the present invention, the porosity of the Venturi-type through-holes of the first devolatilization internals is 0.1% to 30%, the porosity of the Venturi-type through-holes of the second devolatilization internals is 0.5% to 40%, and the porosity of the second devolatilization internals is 1 to 6 times that of the first devolatilization internals.

[0012] In some preferred embodiments of the present invention, the inlet shapes of the Venturi-type through holes of the first devolatilization internals and the second devolatilization internals are circular, elliptical or rectangular, and are evenly distributed on the outlet surfaces of the corresponding devolatilization internals.

[0013] In some preferred embodiments of the present invention, the first devolatilization internal component is provided with a Venturi-type through hole with a contraction section cone angle of 10° to 60°, and an expansion section cone angle of 5° to 30°; the second devolatilization internal component is provided with a Venturi-type through hole with a contraction section cone angle of 5° to 30°, and an expansion section cone angle of 2° to 15°.

[0014] In some preferred embodiments of the present invention, the devolatilizer injected into the devolatilizer injection port is N2, water vapor, methane, ethane or a mixture of the above gases; the viscosity of the polymer solution introduced into the first polymer solution inlet component is 0.1-500 Pa·s, and the viscosity of the polymer solution introduced into the second polymer solution inlet component is 500-20000 Pa·s.

[0015] The present invention also provides a polymer solution devolatilization method of the polymer solution devolatilizer, which comprises the following steps:

[0016] A heat medium is introduced into the cavity to adjust the cavity temperature to the desired devolatilization temperature; the viscosity of the polymer solution to be devolatilized is monitored in real time, and the polymer solution to be devolatilized is switched through the pipeline according to the viscosity of the polymer solution so that the polymer solution to be devolatilized enters the first polymer solution inlet component or the second polymer solution inlet component;

[0017] Heat transfer oil is introduced into the cavity to adjust the cavity temperature to the desired devolatilization temperature; the viscosity of the polymer solution to be devolatilized is monitored in real time, and the polymer solution to be devolatilized is switched through the pipeline according to the viscosity of the polymer solution so that the polymer solution to be devolatilized enters the first polymer solution inlet component or the second polymer solution inlet component;

[0018] Among them, a low-viscosity polymer solution with a viscosity of 0.1-500 Pa·s enters the first polymer solution inlet component, and a high-viscosity polymer solution with a viscosity of 500-20,000 Pa·s enters the second polymer solution inlet component. The Venturi through-hole contraction section of the devolatilization internal component accelerates the material flow rate, breaks and refines the bubbles, and accelerates the diffusion of volatile components into the gas phase; the material flow rate in the expansion section drops sharply, the static pressure drops sharply, and a local negative pressure is formed, which lowers the boiling point of the volatile components and makes them easier to vaporize and escape; after the low-viscosity polymer solution is discharged from the first devolatilization internal component, it falls on the outer surface of the second devolatilization internal component and forms a film, thereby increasing the devolatilization time and mass transfer area of ​​the polymer solution. The film falls along the edge of the second devolatilization internal component to the bottom of the cavity;

[0019] During the devolatilization process, the devolatilizer is continuously injected into the devolatilizer injection port assembly. The devolatilizer enhances the devolatilization process by reducing the partial pressure of volatile components and providing an inert gas environment. The volatile components released during the devolatilization process are discharged from the exhaust port, and the polymer melt after devolatilization is discharged from the polymer discharge port.

[0020] In some preferred embodiments of the present invention, the real-time viscosity of the polymer solution before entering the devolatilizer is detected by a viscosity detection device. The viscosity detection device transmits the viscosity information to the control module, which compares the viscosity information with a detection threshold (the detection threshold can be set to 500 Pa·s) and automatically controls the opening and closing of the pipeline valves based on the comparison result. For example, when the viscosity is lower than the detection threshold, the pipeline valve of the first inlet component is opened and the pipeline valve of the second inlet component is closed; when the real-time viscosity is higher than the detection threshold, the pipeline valve of the second inlet component is opened and the pipeline valve of the first inlet component is closed. This achieves automatic switching of the feed pipeline based on the feed properties. According to a preferred embodiment of the present invention, the pipeline valve of the first inlet component and the pipeline valve of the second inlet component can be integrated into a three-way valve, and the control module selects the outlet branch of the three-way valve based on the viscosity information to achieve feed pipeline switching.

[0021] The present invention has the following outstanding gain effects:

[0022] (1) Low-viscosity polymer is fed from the first devolatilization internal. It has low viscosity and good fluidity. Since the cross-sectional area of ​​the second devolatilization internal is larger, the polymer solution falls onto the inclined surface of the second devolatilization internal. The protrusion of the inclined surface allows the low-viscosity polymer, which is difficult to fall continuously, to form a film on its surface, greatly increasing the devolatilization mass transfer time and mass transfer surface area, and significantly improving the devolatilization efficiency.

[0023] (2) High-viscosity polymers can be continuously and stably formed into strands, but they have poor fluidity and take a long time to pass through the devolatilizer distributor. The pressure acting on the distributor is high, which poses a safety hazard. By switching the valve to feed from the second devolatilizer internal with a larger opening rate, the pressure on the distributor can be effectively reduced. The formation of more strands is also conducive to increasing the devolatilization mass transfer surface area, significantly improving the devolatilization efficiency.

[0024] (3) The contraction section of the Venturi orifice will accelerate the material flow rate and drop the pressure suddenly, which will promote the supercritical nucleation of volatiles through the cavitation effect, forming more bubble nuclei, thereby improving the removal efficiency.

[0025] The above-mentioned device can increase the devolatilization time of low-viscosity polymers and reduce the distributor pressure of high-viscosity polymers. It is suitable for polymers with a wide viscosity range and ensures the long-term stable operation of the device. At the same time, it greatly improves the nucleation, growth and collapse speed of volatile bubbles and improves the devolatilization efficiency. Through static devolatilization, the volatile matter removal efficiency in the polymer can reach more than 90%. BRIEF DESCRIPTION OF THE DRAWINGS

[0026] Figure 1 Schematic diagram of the structure of a polymer solution devolatilizer with a multi-layer distributor according to the present invention;

[0027] Figure 2 Schematic diagram of the structure of the first devolatilization internals;

[0028] Figure 3 Schematic diagram of the structure of the second devolatilization internals. DETAILED DESCRIPTION

[0029] To facilitate understanding of the present invention, the present invention is further described below. However, the present invention can be implemented in many different forms. The following examples are intended to illustrate the present invention only and should not be construed as limiting the scope of the present invention. Where specific conditions are not specified in the examples, the experiments were performed under conventional conditions or the conditions recommended by the manufacturer. Reagents or instruments used, where the manufacturer is not specified, are all commercially available conventional products.

[0030] The following methods were used to test the properties of the polymers produced in the examples described:

[0031] Headspace-gas chromatography is used to measure the residual solvent content of polyolefin elastomers.

[0032] like Figure 1As shown, the present invention provides a polymer solution devolatilizer, comprising: a chamber 1, a first polymer solution inlet assembly 2, a second polymer solution inlet assembly 3, an exhaust port 4, a devolatilizing agent injection port assembly 5, and a polymer discharge port 6. The material outlet end of the first polymer solution inlet assembly 2 is provided with a first devolatilizing internal 7, which is located at the top of the chamber 1; the material outlet end of the second polymer solution inlet assembly 3 is provided with a second devolatilizing internal 8, which is located below the first devolatilizing internal 8; the exhaust port 4 is located at the top of the chamber 1; the devolatilizing agent injection port assembly 5 enters the chamber 1 from the side, and its material outlet is located below the second devolatilizing internal 8; and the polymer discharge port 6 is located at the bottom of the chamber 1. In a specific embodiment of the present invention, the polymer solution feed pipeline is divided into two branches, respectively connected to the first polymer solution inlet assembly 2 and the second polymer solution inlet assembly 3. Valves 9 are provided on the two feed pipelines to switch the feed paths of polymer solutions with different viscosities.

[0033] like Figure 2 FIG. 1 is a schematic diagram of an optional structure of the first devolatilization internal 7 of the present invention. In this embodiment, the overall external shape of the first devolatilization internal is a disc shape (see FIG. Figure 2 The outlet of the first devolatilization internal is downwardly arranged, and a plurality of venturi-type through holes are provided on the outlet surface (see Figure 2 The opening rate of the venturi-type through hole of the first devolatilization internal is 0.1% to 5%; the inlet shape of the venturi-type through hole is circular, elliptical or rectangular and is evenly distributed on the outlet surface. The cone angle of the contraction section of the venturi-type through hole is 10° to 60°, and the cone angle of the expansion section is 5° to 30° (see Figure 2 The right portion of the first devolatilization internals is shown in Figure 1. The Venturi-shaped through-hole contraction section of the first devolatilization internals accelerates material flow, fragments and refines bubbles, increases the mass transfer area, and accelerates the diffusion of volatile components into the gas phase. The expansion section sharply reduces flow rate and static pressure, creating a local negative pressure that significantly lowers the boiling point of volatile components, facilitating their vaporization and escape. In an embodiment of the present invention, the outlet of the first devolatilization internals faces downward, and its cross-sectional area is 20% to 60% of the cross-sectional area of ​​the chamber.

[0034] like Figure 3 As shown, it is a schematic diagram of an optional structure of the second devolatilization internal 8 of the present invention. The opening of the second devolatilization internal is downward and has an expanded diameter design. Its outer surface is an inclined surface, and its outlet surface is provided with a plurality of Venturi-type through holes (see Figure 3 The second devolatilization inner part has a venturi-type through-hole opening rate of 0.5% to 10%. In this embodiment, the overall external shape of the second devolatilization inner part is a truncated cone (see Figure 3The lower left part of the figure has a taper of 30° to 150°. The outer surface of the truncated cone is provided with sawtooth, stepped, or wavy protrusions. The maximum cross-sectional area of ​​the second devolatilization internal is 30% to 80% of the cross-sectional area of ​​the cavity and 1 to 3 times the cross-sectional area of ​​the first devolatilization internal. The inlet shape of the Venturi-type through hole is circular, elliptical, or rectangular and is evenly distributed on the outlet surface. The cone angle of the contraction section of the Venturi-type through hole is 5° to 30°, and the cone angle of the expansion section is 2° to 15° (see Figure 3 The second devolatilization internals’ Venturi through-hole contraction and expansion sections create a dynamic devolatilization environment that stimulates low pressure and enhances mass transfer, promoting the removal of volatiles.

[0035] Example 1:

[0036] In this embodiment, the flow rate of the polyolefin elastomer entering the devolatilizer is 150 kg / h, the solid content is 90 wt%, the cavity is heated by 240° C. hot oil, the temperature of the polyolefin elastomer solution at the outlet is 220° C., the operating temperature of the devolatilizer is 230° C., the operating pressure is 0.01 MPaG, the bottom of the cavity is inverted conical with a cone angle of 60°, the cavity height is 200 cm, and the cavity cross-sectional area is 800 cm. 2 .

[0037] The first devolatilization internal is disc-shaped with a cross-sectional area of ​​200 cm 2 , open circular Venturi through holes, a total of 30 holes, the hole diameter is 0.5 cm, the hole spacing is 0.8 cm, and they are evenly distributed in a square shape. The cone angle of the Venturi contraction section is 10°, and the cone angle of the expansion section is 5°;

[0038] The second devolatilization internal is a truncated cone with a taper of 80°. There are protrusions on both sides of the inclined surface. The protrusions are serrated. The cross-sectional area of ​​the second devolatilization internal is 300cm 2 , open circular Venturi through holes, a total of 50 holes, the hole diameter is 0.6cm, the hole spacing is 0.8cm, and they are evenly distributed in a regular triangle. The cone angle of the Venturi contraction section is 10°, and the cone angle of the expansion section is 8°.

[0039] The distance between the first devolatilization internal component and the second devolatilization internal component is 80 cm, and N2 is injected into the devolatilization auxiliary agent injection port.

[0040] When the viscosity of the polymer solution is 100 Pa·s, the valve is switched to allow the polymer solution (volatile content 10 wt%) to enter the cavity from the first devolatilization internal. The inlet pressure of the first devolatilization internal is 1.2 MPa, and the VOC content in the outlet polymer is 280 ppm.

[0041] When the viscosity of the polymer solution is 1000 Pa·s, the polymer solution (volatile content 10 wt%) enters the cavity from the second devolatilization internal by switching the valve. The inlet pressure of the second devolatilization internal is 1.8 MPa, and the VOC content in the outlet polymer is 200 ppm.

[0042] Example 2:

[0043] In this embodiment, the flow rate of the polyolefin elastomer entering the devolatilizer is 150 kg / h, the solid content is 90 wt%, the cavity is heated by 240°C hot oil, the temperature of the polyolefin elastomer solution at the outlet is 220°C, the operating temperature of the devolatilizer is 230°C, the operating pressure is 0.01 MPaG, the bottom of the cavity is inverted conical with a cone angle of 60°, the cavity height is 200 cm, and the cavity cross-sectional area is 800 cm 2 .

[0044] The first devolatilization internal is disc-shaped with a cross-sectional area of ​​200 cm 2 , open circular Venturi through holes, with a total of 30 holes, each with a diameter of 0.5 cm, a hole spacing of 0.8 cm, and a regular triangle distribution. The cone angle of the Venturi contraction section is 10°, and the cone angle of the expansion section is 5°;

[0045] The second devolatilization internal is a truncated cone with a taper of 80°. There are protrusions on both sides of the inclined surface. The protrusions are serrated. The cross-sectional area of ​​the second devolatilization internal is 300cm 2 , open circular Venturi through holes, a total of 50 holes, the hole diameter is 0.6cm, the hole spacing is 0.8cm, distributed in a regular triangle, the cone angle of the Venturi contraction section is 10°, and the cone angle of the expansion section is 8°.

[0046] The distance between the first devolatilization internal component and the second devolatilization internal component is 70 cm, and the devolatilization auxiliary agent injection port injects CO2;

[0047] When the viscosity of the polymer solution is 100 Pa·s, the valve is switched to allow the polymer solution (volatile content 10 wt%) to enter the devolatilization tank from the first devolatilization internal. The inlet pressure of the first devolatilization internal is 1.2 MPa, and the VOC content in the outlet polymer is 350 ppm.

[0048] When the viscosity of the polymer solution is 1000 Pa·s, the polymer solution (volatile content 10 wt%) enters the devolatilization tank from the second devolatilization internal by switching the valve. The inlet pressure of the second devolatilization internal is 1.8 MPa, and the VOC content in the outlet polymer is 300 ppm.

[0049] Comparative Example 1.1:

[0050] In this example, the polyolefin elastomer entering the devolatilizer has a flow rate of 150 kg / h and a solids content of 90 wt%. The cavity is heated with 240°C hot oil, the polyolefin elastomer solution temperature at the outlet is 230°C, the devolatilizer operates at 240°C, and the operating pressure is 0.01 MPaG. The cavity bottom is inverted conical with a cone angle of 60°, the cavity height is 200 cm, and the cavity cross-sectional area is 700 cm. 2 .

[0051] The devolatilization internals are disc-shaped with a cross-sectional area of ​​200 cm 2 , open circular through holes, a total of 20 holes, the hole diameter is 0.5cm, the hole spacing is 0.8cm, and they are distributed in a regular triangle;

[0052] The viscosity of the polymer solution was 1000 Pa·s. The polymer solution (volatile content 10 wt%) entered the devolatilizer from the devolatilizer internals. During the experiment, the devolatilizer internals inlet pressure (>8 MPa, the devolatilizer internals inlet safety pressure is 8 MPa) was stopped.

[0053] Comparative Example 1.2:

[0054] In this example, the polyolefin elastomer entering the devolatilizer has a flow rate of 150 kg / h and a solids content of 90 wt%. The cavity is heated with 240°C hot oil, the polyolefin elastomer solution temperature at the outlet is 230°C, the devolatilizer operates at 240°C, and the operating pressure is 0.01 MPaG. The cavity bottom is inverted conical with a cone angle of 60°, the cavity height is 200 cm, and the cavity cross-sectional area is 700 cm. 2 .

[0055] The devolatilization internals are disc-shaped with a cross-sectional area of ​​200 cm 2 , open circular through holes, a total of 40 holes, the hole diameter is 0.5cm, the hole spacing is 0.8cm, and they are distributed in a regular triangle;

[0056] The viscosity of the polymer solution is 100 Pa·s. The polymer solution (volatile content 10 wt%) enters the devolatilizer from the devolatilization internals. The inlet pressure of the devolatilization internals is 0.1 MPa. The VOC content of the outlet melt is 45023 ppm.

[0057] Comparative Example 2:

[0058] In this example, the polyolefin elastomer entering the devolatilizer has a flow rate of 150 kg / h and a solids content of 90 wt%. The cavity is heated with 240°C hot oil, the polyolefin elastomer solution temperature at the outlet is 230°C, the devolatilizer operates at 240°C, and the operating pressure is 0.01 MPaG. The cavity bottom is inverted conical with a cone angle of 60°, the cavity height is 200 cm, and the cavity cross-sectional area is 700 cm. 2 .

[0059] The first devolatilization internal is disc-shaped with a cross-sectional area of ​​200 cm 2 , open circular through holes, a total of 30 holes, the hole diameter is 0.5cm, the hole spacing is 0.8cm, and they are distributed in a regular triangle;

[0060] The second devolatilization internal is a truncated cone with a taper of 80°. There are protrusions on both sides of the inclined surface. The protrusions are serrated. The cross-sectional area of ​​the second devolatilization internal is 300cm 2 , open circular through holes, a total of 50 holes, the hole diameter is 0.6cm, the hole spacing is 0.8cm, and they are distributed in a regular triangle.

[0061] The distance between the first devolatilization internal component and the second devolatilization internal component is 80 cm, and CO2 is injected into the devolatilization auxiliary agent injection port.

[0062] When the polymer solution viscosity is 100 Pa·s, the polymer solution (volatile content 10 wt%) is fed from the first devolatilization internal into the devolatilization tank by switching the valve. The inlet pressure of the devolatilization internal is 1.3 MPa, and the VOC content of the outlet polymer is 2684 ppm.

[0063] When the viscosity of the polymer solution is 1000 Pa·s, the polymer solution (volatile content 10 wt%) enters the devolatilization tank from the second devolatilization internal by switching the valve. The inlet pressure of the devolatilization internal is 1.8 MPa, and the VOC content in the outlet polymer is 1589 ppm.

[0064] The differences between the devices and results of each embodiment and the comparative example are shown in Table 1.

[0065] Table 1 Differences between the devices and results of the embodiment and the comparative example

[0066]

[0067] The above-described embodiments merely illustrate several implementations of the present invention, and while their descriptions are relatively specific and detailed, they should not be construed as limiting the scope of the present invention. It should be noted that a person skilled in the art would be able to make numerous variations and improvements without departing from the spirit of the present invention, all of which fall within the scope of protection of the present invention. Therefore, the scope of protection of the present invention shall be determined by the appended claims.

Claims

1. A polymer solution devolatilizer, characterized in that: The devolatilizer comprises a cavity, a first polymer solution inlet assembly, a second polymer solution inlet assembly, an exhaust port, a devolatilization aid injection port assembly and a polymer discharge port; The cavity is provided with a jacket for introducing a heat medium, including but not limited to thermal oil and high-pressure steam, to regulate the temperature in the cavity; The outlet end of the first inlet assembly of the polymer solution is provided with a first devolatilization internal; the first devolatilization internal is located at the top of the cavity, with its outlet facing downward, and a plurality of venturi-type through holes are opened on the outlet surface of the first devolatilization internal; A second devolatilization internal is provided at the outlet end of the second inlet assembly for the polymer solution. The second devolatilization internal is located directly below the first devolatilization internal, has an opening facing downward and is designed to have an expanded diameter. The outer surface of the second devolatilization internal is an inclined surface, and a plurality of Venturi-type through holes are provided on its outlet surface. The devolatilization aid injection port assembly is arranged on the side of the cavity, and its outlet position is located below the second devolatilization internal component; The polymer discharge port is located at the bottom of the cavity and is used to discharge the devolatilized polymer; The exhaust port is located at the top of the chamber and is used to exhaust volatile matter removed from the polymer solution.

2. The polymer solution devolatilizer according to claim 1, characterized in that The outlet cross-sectional area of ​​the first devolatilization internal is 20% to 60% of the cavity cross-sectional area; the maximum cross-sectional area of ​​the second devolatilization internal is 30% to 80% of the cavity cross-sectional area, and is 1 to 3 times the cross-sectional area of ​​the first devolatilization internal.

3. The polymer solution devolatilizer according to claim 1, characterized in that The overall external shape of the second devolatilization internal component is a truncated cone with a taper of 30° to 150°; the outer surface of the truncated cone is smooth or provided with serrated, stepped or wavy protrusions.

4. The polymer solution devolatilizer according to claim 1, characterized in that The distance between the first devolatilization internal and the second devolatilization internal is 0.2 to 1 times the diameter of the cavity.

5. The polymer solution devolatilizer according to claim 1, characterized in that The opening rate of the Venturi-type through-holes of the first devolatilization internal component is 0.1% to 30%, and the opening rate of the Venturi-type through-holes of the second devolatilization internal component is 0.5% to 40%.

6. The polymer solution devolatilizer according to claim 1 or 55, characterized in that The porosity of the second devolatilization internal is 1 to 6 times that of the first devolatilization internal.

7. The polymer solution devolatilizer according to claim 1 or 55, characterized in that The inlet shapes of the Venturi-type through holes of the first devolatilization internals and the second devolatilization internals are circular, elliptical or rectangular, and are evenly distributed on the outlet surfaces of the corresponding devolatilization internals.

8. The polymer solution devolatilizer according to claim 77, characterized in that The first devolatilization internal component is provided with a Venturi-type through hole with a contraction section cone angle of 10° to 60° and an expansion section cone angle of 5° to 30°; the second devolatilization internal component is provided with a Venturi-type through hole with a contraction section cone angle of 5° to 30° and an expansion section cone angle of 2° to 15°.

9. The polymer solution devolatilizer according to claim 1, characterized in that The devolatilizer injected into the devolatilizer injection port is N2, water vapor, methane, ethane or a mixture of the above gases; the viscosity of the polymer solution introduced into the first polymer solution inlet component is 0.1-500Pa·s, and the viscosity of the polymer solution introduced into the second polymer solution inlet component is 500-20000Pa·s.

10. A method for devolatilizing a polymer solution based on the polymer solution devolatilizer according to claim 1, characterized in that: The steps include: A heat medium is introduced into the cavity to adjust the cavity temperature to the desired devolatilization temperature; the viscosity of the polymer solution to be devolatilized is monitored in real time, and the polymer solution to be devolatilized is switched through the pipeline according to the viscosity of the polymer solution so that the polymer solution to be devolatilized enters the first polymer solution inlet component or the second polymer solution inlet component; Among them, a low-viscosity polymer solution with a viscosity of 0.1-500 Pa·s enters the first polymer solution inlet component, and a high-viscosity polymer solution with a viscosity of 500-20,000 Pa·s enters the second polymer solution inlet component. The Venturi through-hole contraction section of the devolatilization internal component accelerates the material flow rate, breaks and refines the bubbles, and accelerates the diffusion of volatile components into the gas phase; the material flow rate in the expansion section drops sharply, the static pressure drops sharply, and a local negative pressure is formed, which lowers the boiling point of the volatile components and makes them easier to vaporize and escape; after the low-viscosity polymer solution is discharged from the first devolatilization internal component, it falls on the outer surface of the second devolatilization internal component and forms a film, thereby increasing the devolatilization time and mass transfer area of ​​the polymer solution. The film falls along the edge of the second devolatilization internal component to the bottom of the cavity; During the devolatilization process, the devolatilizer is continuously injected into the devolatilizer injection port assembly. The devolatilizer enhances the devolatilization process by reducing the partial pressure of volatile components and providing an inert gas environment. The volatile components released during the devolatilization process are discharged from the exhaust port, and the polymer melt after devolatilization is discharged from the polymer discharge port.

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