Solution-method polyethylene preparation device capable of prepolymerizing catalyst
By setting a premixer between the agitator and the kettle to form a low-temperature buffer zone, the catalyst and polymer are prepolymerized at low temperature, solving the problem of catalyst deactivation due to high temperature, and improving the mixing efficiency and the service life of the catalyst.
Patent Information
- Application Number
- CN202422651373.7
- Authority / Receiving Office
- CN · China
- Patent Type
- Utility models(China)
- Current Assignee / Owner
- Filing Date
- 2024-10-31
- Publication Date
- 2025-10-10
- Estimated Expiration
- 2034-10-31
AI Technical Summary
In the production of solution-process polyethylene using an existing stirred tank reactor, the catalyst is easily deactivated due to high temperature, resulting in poor mixing efficiency.
A premixer is set between the agitator and the kettle body to form a low-temperature buffer zone, so that the catalyst and polymer can undergo prepolymerization reaction under low-temperature conditions to avoid direct contact with the high-temperature stirring paddle.
It effectively extends the service life of the catalyst, improves the mixing efficiency, and avoids the problem of catalyst deactivation due to high temperature.
Smart Images
Figure CN223417267U_ABST
Abstract
Description
Technical Field
[0001] The utility model relates to the technical field of solution-process polyethylene preparation, in particular to a solution-process polyethylene preparation device capable of catalyst prepolymerization. Background Art
[0002] Stirred reactors are typically powered by an external motor, which, through a reduction gear, drives the agitator paddle on the agitator shaft, thereby driving the fluid within the reactor to achieve optimal mixing. Widely used in the chemical, pharmaceutical, biochemical, and environmental chemical industries, they are essential units for transferring mass, momentum, and energy, as well as chemical reactions, in single-phase and multiphase fluids. They offer excellent mixing, a large contact area, and high heat and mass transfer efficiencies.
[0003] The Sclairtech process for solution-processed polyethylene production uses 1-butene and 1-octene as comonomers and can also produce homopolymer HDPE and ethylene / 1-butene / 1-octene terpolymers. The reaction temperature is 200-300°C. This high temperature maximizes the use of reaction heat. The reactor has a high overall height-to-diameter ratio and multiple impeller layers to accommodate both overall plug flow and localized fully mixed flow.
[0004] A stirred tank reactor consists of an agitator and a kettle. The agitator includes a transmission device, a stirring shaft (including a shaft seal), and a stirring paddle. The kettle includes a barrel, a jacket, internals, coils, and a draft tube. The materials are mixed evenly through the rotating shear of the agitator and the obstruction of the baffle. However, in the Sclairtech process for solution-based polyethylene production, the catalyst is directly stirred in the existing stirred tank reactor, which can easily cause the catalyst to deactivate due to high temperatures. Utility Model Content
[0005] The utility model provides a solution process polyethylene preparation device capable of catalyst prepolymerization to solve the above technical problems.
[0006] In order to achieve the above purpose, the technical solution of the utility model is:
[0007] A solution-process polyethylene preparation device capable of catalyst prepolymerization comprises an agitator and a kettle body, wherein the agitator comprises: a transmission device, a stirring shaft and a stirring paddle; a premixer feed port is provided at the bottom of the kettle body, and a stirring kettle feed port is provided on the side wall of the kettle body; the agitator further comprises a premixer, which is located between the premixer feed port and the stirring kettle feed port; the premixer rotates with the stirring shaft to form a low-temperature buffer zone, and the premixer is used to mix the catalyst and the polymer monomers in the low-temperature buffer zone.
[0008] Preferably, the premixer comprises a stator and a rotor arranged concentrically, the stator is arranged around the stator and is fixedly mounted on the inner wall of the kettle body, and the rotor rotates with the stirring shaft.
[0009] Preferably, a plurality of stator columns are fixed on the stator, the stator columns are arranged along the axial direction of the stirring shaft, and the plurality of stator columns are evenly distributed around the axis of the stirring shaft;
[0010] A plurality of rotor columns are fixedly arranged on the rotor, the rotor columns are arranged along the axial direction of the stirring shaft, and the plurality of rotor columns are evenly distributed around the circumference of the axis of the stirring shaft.
[0011] Preferably, the number of stator poles is 36, and the angle between stator poles is 10°; the number of rotor poles is 30, and the angle between stator poles is 12°.
[0012] Preferably, the stator column is arc-shaped along the circumferential direction of the stirring shaft, and the corresponding angle of the stator column is 4.27°; the rotor column is arc-shaped along the circumferential direction of the stirring shaft, and the corresponding angle of the rotor column is 4.94°.
[0013] Preferably, the stator and the rotor are both annular, the inner diameter of the stator is 750 mm, and the outer diameter of the rotor is 650 mm.
[0014] Preferably, the stator and the rotor are both annular, a plurality of connecting columns connect the stator and the kettle body, a plurality of supporting columns connect the rotor and the rotor shaft, and the rotor shaft is coaxially fixed to the bottom end of the stirring shaft.
[0015] Preferably, the plurality of connecting columns are evenly distributed around the circumference of the axis of the rotor shaft, and the plurality of supporting columns are evenly distributed around the circumference of the axis of the rotor shaft.
[0016] Preferably, there are three stirring paddles, which are spaced apart along the axial direction of the stirring shaft.
[0017] Preferably, a plurality of baffles are fixedly provided on the inner wall of the kettle body.
[0018] Beneficial effects:
[0019] The present application discloses a solution-based polyethylene preparation device capable of catalyst prepolymerization. By providing a premixer, a low-temperature buffer zone is formed in the area between the premixer feed port and the stirred tank feed port. The premixer allows the catalyst and polymer to be mixed in the low-temperature buffer zone for prepolymerization, thereby avoiding the catalyst from being directly stirred by a stirring paddle and deactivated by exposure to high temperatures. This can effectively alleviate the problems of catalyst deactivation and poor mixing efficiency in a stirred tank reactor. BRIEF DESCRIPTION OF THE DRAWINGS
[0020] In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the following is a brief introduction to the drawings required for use in the embodiments or the description of the prior art. Obviously, the drawings described below are some embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying any creative labor.
[0021] Figure 1 This is a schematic structural diagram of a solution-process polyethylene preparation device capable of catalyst prepolymerization disclosed in the present utility model;
[0022] Figure 2 for Figure 1 Cross-sectional view of AA;
[0023] Figure 3 This is a schematic structural diagram of a premixer for a solution-based polyethylene preparation device capable of catalyst prepolymerization disclosed in the present utility model;
[0024] Figure 4 The utility model discloses a top view of a premixer of a solution-process polyethylene preparation device capable of catalyst prepolymerization.
[0025] 1. Kettle body; 11. Premixer feed port; 12. Mixing kettle feed port;
[0026] 21. Stirring shaft; 22. Stirring paddle; 23. Stator; 231. Stator column; 232. Connecting column; 24. Rotor; 241. Rotor column; 242. Support column; 25. Rotor shaft; 26. Baffle. DETAILED DESCRIPTION
[0027] To make the purpose, technical solutions, and advantages of the embodiments of the present invention more clear, the technical solutions in the embodiments of the present invention will be clearly and completely described below in conjunction with the drawings in the embodiments of the present invention. Obviously, the embodiments described are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without making creative efforts shall fall within the scope of protection of the present invention.
[0028] A solution-based polyethylene preparation device capable of catalyst prepolymerization, combined with Figure 1 、 Figure 2 、 Figure 3 and Figure 4 As shown, it includes an agitator and a kettle body 1. The agitator includes: a transmission device, an agitator shaft 21 and an agitator paddle 22. A premixer feed port 11 is provided at the bottom of the kettle body 1, and a stirring kettle feed port 12 is provided on the side wall of the kettle body 1. The agitator also includes a premixer, which is located between the premixer feed port 11 and the stirring kettle feed port 12. The premixer rotates with the agitator shaft 21 to form a low-temperature buffer zone. The premixer is used to mix the catalyst and the polymer monomers in the low-temperature buffer zone. The premixer allows the catalyst and the polymer to be mixed in the low-temperature buffer zone for prepolymerization reaction, avoiding the catalyst being directly stirred by the agitator paddle 22 and subjected to high temperature and deactivation, thereby extending the service life of the catalyst and effectively alleviating the problems of catalyst deactivation and poor mixing efficiency in the stirred kettle reactor.
[0029] Specifically, the kettle body 1 includes: a cylindrical barrel, a top hemispherical cover, and a bottom hemispherical cover. The top hemispherical cover is provided with a circular hole with a diameter of 150 mm to facilitate the connection of the transmission device after the stirring shaft 21 is extended. A circular hole with a diameter of 200 mm is provided in the center of the bottom hemispherical cover as the premixer feed port 11, and a circular hole with a diameter of 200 mm is provided on the side wall of the barrel as the stirring kettle feed port 12, and the stirring kettle feed port 12 is at the same height as the bottom end of the stirring shaft 21. The height of the barrel is 3399 mm, and the diameter of the barrel, the spherical diameter of the top hemispherical cover, and the spherical diameter of the bottom hemispherical cover are all 1016 mm. The height of the stirring shaft 21 is 3000 mm, and the diameter of the stirring shaft 21 is 80 mm.
[0030] Preferably, the premixer includes a stator 23 and a rotor 24 arranged concentrically. The stator 23 is arranged around the stator 23 and fixedly mounted on the inner wall of the kettle body 1. The rotor 24 rotates with the stirring shaft 21. The rotating rotor 24 cooperates with the fixed stator 23 to form a low-temperature buffer zone, and the catalyst and polymer are mixed in the low-temperature buffer zone to perform a prepolymerization reaction.
[0031] Preferably, the stator 23 is fixedly provided with a plurality of stator columns 231, which are arranged along the axial direction of the stirring shaft 21 and are evenly distributed around the axis of the stirring shaft 21. The rotor 24 is fixedly provided with a plurality of rotor columns 241, which are arranged along the axial direction of the stirring shaft 21 and are evenly distributed around the axis of the stirring shaft 21. The rotor columns 241 rotate with the rotor 24 and cooperate with the stator columns 231 to assist in stirring.
[0032] Preferably, the number of stator poles 231 is 36, and the angle between the stator poles 231 is 10°; the number of rotor poles 241 is 30, and the angle between the stator poles 231 is 12°.
[0033] Preferably, the stator column 231 is arc-shaped along the circumferential direction of the stirring shaft 21, and the corresponding angle of the stator column 231 is 4.27°; the rotor column 241 is arc-shaped along the circumferential direction of the stirring shaft 21, and the corresponding angle of the rotor column 241 is 4.94°.
[0034] Preferably, the stator 23 and the rotor 24 are both annular, with an inner diameter of the stator 23 being 750 mm and an outer diameter of the rotor 24 being 650 mm, so that the stator 23 and the rotor 24 are spaced apart from each other, allowing the reactants to pass between the stator 23 and the rotor 24, which is conducive to ensuring the efficiency and effect of premixing.
[0035] Specifically, the stator column 231 is fixed on the upper surface of the stator 23, and the rotor column 241 is fixed on the upper surface of the rotor 24. Along the radial direction of the stirring shaft 21: the size of the stator column 231 is consistent with the size of the stator 23, and the size of the rotor column 241 is consistent with the size of the rotor 24.
[0036] Specifically, the stator 23 has an outer diameter of 800 mm and a height of 50 mm, and the stator column 231 has a height of 150 mm. The rotor 24 has an inner diameter of 600 mm and a height of 50 mm, and the rotor column 241 has a height of 150 mm.
[0037] Preferably, the stator 23 and the rotor 24 are both annular, with a plurality of connecting columns 232 connecting the stator 23 and the kettle body 1, and a plurality of supporting columns 242 connecting the rotor 24 and the rotor shaft 25. The rotor shaft 25 is coaxially fixed to the bottom end of the stirring shaft 21. On the basis of ensuring the installation of the stator 23 and the rotor 24, the reactants can pass between the stator 23 and the inner wall of the kettle body 1 and between the inner ring of the rotor 24, ensuring the efficiency and effect of premixing, and ensuring that they can normally enter the upper part of the kettle body 1 for sufficient reaction.
[0038] Preferably, the plurality of connecting columns 232 are evenly distributed around the axis of the rotor shaft 25 so that the plurality of connecting columns 232 evenly support the stator 23; the plurality of supporting columns 242 are evenly distributed around the axis of the rotor shaft 25, which not only realizes uniform support for the rotor 24 but also helps to ensure the rotational balance of the rotor 24.
[0039] Specifically, the rotor shaft 25 has a diameter of 50 mm and a height of 600 mm.
[0040] Specifically, the rotor shaft 25 is coaxially arranged with the agitator shaft 21, with the top end of the rotor shaft 25 welded to the bottom end of the agitator shaft 21. One end of the connecting column 232 is welded to the bottom end of the cylinder 1, and the other end is welded to the outer circumference of the stator 23. One end of the supporting column 242 is welded to the inner wall of the rotor 24, and the other end is welded to the outer circumference of the rotor shaft 25. The lower surfaces of the stator 23 and rotor 24 are aligned with the bottom end of the cylinder, ensuring that the stator 23 and rotor 24 are located at the connection between the cylinder and the bottom hemispherical cover.
[0041] Specifically, there are eight support columns 242 arranged in a cross-section. The cross-section of the support columns 242 is 5 mm wide and 4 mm thick, ensuring stable support for the rotor 24 while minimizing interference with the flow of reactants.
[0042] Preferably, there are three stirring paddles 22 , and the three stirring paddles 22 are spaced apart along the axial direction of the stirring shaft 21 .
[0043] Specifically, the diameter of the stirring paddle 22 is 640 mm and the vertical height is 94.6 mm. The thickness of the stirring paddle 22 blade is 9.2 mm and the inclination angle is 46.6°. The three stirring paddles 22 are spaced 635 mm apart, and the distance between the bottom stirring paddle 22 and the bottom end of the stirring shaft 21 is 552 mm.
[0044] Preferably, a plurality of baffles 26 are fixedly mounted on the inner wall of the kettle body 1. The baffles 26 facilitate cooperation with the agitator paddles 22 to achieve overall plug flow and localized full mixing. In this embodiment, there are four baffles 26, each 10 mm thick and 3190 mm high. The angle between adjacent baffles 26 is 90°.
[0045] The steps for prepolymerization using the device of this application are as follows:
[0046] In the first step, a portion of the solvent hexane and the comonomer 2-octene are added to the device from the premixer feed port, and another portion of the solvent hexane and the comonomer 2-octene are added to the device from the stirring tank feed port. At this time, a thermometer is set in the premixer of the device to display the temperature of the solvent hexane and the comonomer 2-octene.
[0047] In the second step, a portion of the comonomer 1 ethylene is added to the device from the premixer feed port using a micro-regulating valve. At this time, the temperature displayed on the thermometer will drop by 2-3 degrees Celsius, and another portion of the comonomer 1 ethylene is added to the device from the stirring tank feed port.
[0048] In the third step, the primary catalyst, metallocene, and the co-catalyst, alkylaluminum, are dissolved in toluene. The catalysts are then added to the premixer feed port via a catalyst delivery pump. The catalysts react with the pre-added comonomer, ethylene, for a prepolymerization reaction. The reaction pressure is 10 MPa, the stirring speed is set at 600 rpm, and the reaction starting temperature is 140°C. The prepolymerization of the catalyst and the comonomer, ethylene, releases heat, causing the thermometer temperature to rise by 1-2°C. This prepolymerized catalyst is more resistant to high temperatures and has increased activity.
[0049] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention, rather than to limit it. Although the present invention has been described in detail with reference to the aforementioned embodiments, those skilled in the art should understand that they can still modify the technical solutions described in the aforementioned embodiments, or replace some or all of the technical features therein with equivalents. However, these modifications or replacements do not deviate the essence of the corresponding technical solutions from the scope of the technical solutions of the embodiments of the present invention.
Claims
1. A solution-process polyethylene production device capable of catalyst prepolymerization, comprising an agitator and a kettle (1), wherein the agitator comprises: The invention relates to a transmission device, a stirring shaft (21) and a stirring paddle (22), characterized in that a premixer feed port (11) is provided at the bottom of the kettle body (1), and a stirring kettle feed port (12) is provided on the side wall of the kettle body (1); the stirrer further comprises a premixer, the premixer is located between the premixer feed port (11) and the stirring kettle feed port (12), the premixer rotates with the stirring shaft (21) to form a low-temperature buffer zone, and the premixer is used for monomer mixing of catalyst and polymer in the low-temperature buffer zone.
2. A solution-process polyethylene production device capable of catalyst prepolymerization according to claim 1, characterized in that: The premixer comprises a stator (23) and a rotor (24) which are arranged concentrically. The stator (23) is arranged around the stator (23) and is fixedly mounted on the inner wall of the kettle body (1). The rotor (24) rotates with the stirring shaft (21).
3. A solution-process polyethylene production device capable of catalyst prepolymerization according to claim 2, characterized in that: A plurality of stator columns (231) are fixedly provided on the stator (23), the stator columns (231) are arranged along the axial direction of the stirring shaft (21), and the plurality of stator columns (231) are evenly distributed around the circumference of the axis of the stirring shaft (21); A plurality of rotor columns (241) are fixedly provided on the rotor (24), and the rotor columns (241) are arranged along the axial direction of the stirring shaft (21). The plurality of rotor columns (241) are evenly distributed around the circumference of the axis of the stirring shaft (21).
4. A solution-process polyethylene production device capable of catalyst prepolymerization according to claim 3, characterized in that: The number of the stator columns (231) is 36, and the angle between the stator columns (231) is 10°; the number of the rotor columns (241) is 30, and the angle between the stator columns (231) is 12°.
5. The solution-process polyethylene production device capable of catalyst prepolymerization according to claim 4, characterized in that: The stator column (231) is arc-shaped along the circumferential direction of the stirring shaft (21), and the corresponding angle of the stator column (231) is 4.27°; the rotor column (241) is arc-shaped along the circumferential direction of the stirring shaft (21), and the corresponding angle of the rotor column (241) is 4.94°.
6. The solution-process polyethylene production device capable of catalyst prepolymerization according to claim 5, characterized in that: The stator (23) and the rotor (24) are both annular, the inner diameter of the stator (23) is 750 mm, and the outer diameter of the rotor (24) is 650 mm.
7. The solution-process polyethylene production device capable of catalyst prepolymerization according to claim 2, characterized in that: The stator (23) and the rotor (24) are both annular, a plurality of connecting columns (232) connect the stator (23) and the kettle body (1), a plurality of supporting columns (242) connect the rotor (24) and the rotor shaft (25), and the rotor shaft (25) is coaxially fixed to the bottom end of the stirring shaft (21).
8. The solution-process polyethylene production device capable of catalyst prepolymerization according to claim 7, characterized in that: The plurality of connecting columns (232) are evenly distributed around the circumference of the axis of the rotor shaft (25), and the plurality of supporting columns (242) are evenly distributed around the circumference of the axis of the rotor shaft (25).
9. The solution-process polyethylene production device capable of catalyst prepolymerization according to claim 1, characterized in that: There are three stirring paddles (22), and the three stirring paddles (22) are arranged at intervals along the axial direction of the stirring shaft (21).
10. The solution-process polyethylene production device capable of catalyst prepolymerization according to claim 1, characterized in that: A plurality of baffles (26) are also fixedly provided on the inner wall of the kettle body (1).