Spray membrane separation device for polyolefin oligomer separation

Abstract

The utility model relates to a spray film separation device for polyolefin oligomer separation, which comprises a flash evaporation unit for flash evaporation separation of light and heavy components of the oligomer, and the flash evaporation unit is connected with a spraying mechanism for forming a spray film from a molten oligomer. According to the spray film separation device disclosed by the utility model, molten polyolefin oligomer can form a liquid-phase particle film, and the liquid-phase particle film enters the flash evaporation unit in a spray film form for flash evaporation separation, so that efficient and thorough separation of light and heavy components is realized.

Description

Technical Field

[0001] The utility model relates to the technical field of polyolefin oligomer separation, in particular to a spray membrane separation device for separating polyolefin oligomers. Background Art

[0002] Polyolefins are a general term for thermoplastic resins derived from the polymerization or copolymerization of α-olefins such as ethylene, propylene, 1-butene, 1-pentene, 1-hexene, 1-octene, and 4-methyl-1-pentene, as well as certain cycloolefins. Polyethylene, a key component of polyolefins, is a crucial engineering plastic with widespread applications in industries such as packaging, construction, and automotive. Ultra-high molecular weight polyethylene (UHMWPE) is a particularly widely used polyethylene, exhibiting excellent wear resistance, high impact strength, excellent self-lubrication, and low-temperature resistance.

[0003] Currently, the slurry process is a relatively mature process for producing polyolefins. Specifically, an aliphatic hydrocarbon inert solvent and monomers are combined to form a polymer under the action of a catalyst. The polymer is suspended in the solvent, and products with varying properties can be obtained by controlling the reaction conditions. However, during the slurry process, the catalyst activity is affected by factors such as the solvent environment, resulting in low monomer conversion rates and the production of large amounts of polyolefin oligomers. For example, during the polyethylene production process, a significant amount of polyethylene oligomers is generated. These oligomers contain a number of high-value-added products (such as polyethylene wax), which typically require separation and purification.

[0004] Chinese patent CN108219189A discloses a method for separating polyethylene oligomers. Polyethylene oligomers are added to a light fraction removal kettle and heated, and then low-pressure superheated steam is introduced for steam distillation. The mixed steam formed by the water vapor and the light components in the polyethylene oligomers enters a condenser through a pipeline at the top of the light fraction removal kettle, where it is condensed and separated to obtain light alkane oil. The remaining material in the light fraction removal kettle is passed through a feed pipeline at the bottom of the kettle into a dehydration kettle, and polyethylene wax is obtained after dehydration. This patent uses a steam stripping process to remove the light components in the polyethylene oligomers to obtain high-quality polyethylene wax. However, this method has low separation efficiency and requires a dehydration step, which increases the complexity of the system. Further research is needed to improve the efficiency of oligomer separation and increase the ease of operation. Utility Model Content

[0005] The purpose of the utility model is to provide a spray membrane separation device for separating polyolefin oligomers in order to solve the above problems.

[0006] The purpose of the utility model is achieved through the following technical solutions:

[0007] A spray membrane separation device for separating polyolefin oligomers comprises a flash evaporation unit for flash evaporating and separating light and heavy components of oligomers. The flash evaporation unit is connected to a spray mechanism for forming a spray film from molten oligomers.

[0008] The utility model discloses a spray membrane separation device, which can form a liquid phase particle film from the melted and pressurized polyolefin oligomer, and enter the flash evaporation unit in the form of a spray film for flash evaporation, thereby realizing efficient separation of light and heavy components. The separated gas phase light components are discharged from the top of the flash evaporation unit, and the liquid phase heavy components are discharged from the bottom of the flash evaporation unit.

[0009] As a preferred technical solution of the present invention, the flash evaporation unit includes a flash evaporation tank, or other flash evaporation equipment is used.

[0010] As a preferred technical solution of the present invention, the flash tank adopts a vacuum flash tank, which can remove light components more effectively.

[0011] As a preferred technical solution of the present invention, the spray mechanism includes an atomizing nozzle or a nozzle, and the aperture of the atomizing nozzle or the nozzle is selected according to actual conditions. For example, an atomizing nozzle or a nozzle with an aperture of 1 to 10 mm is used, and a solid conical spray is preferably used to produce a circular impact area.

[0012] As a preferred technical solution of the present invention, the injection mechanism is a rotary atomizing nozzle, which helps to increase atomization efficiency, improve atomization uniformity, enhance liquid dispersibility and reduce particle size, and can effectively improve the spray separation effect.

[0013] As a preferred technical solution of the present invention, the rotary atomizing nozzle includes an outer sleeve, a rotary connecting pipe and at least one porous nozzle;

[0014] The rotary connecting tube is rotatably connected to the outer sleeve along the axial direction;

[0015] The multi-hole nozzle is fixedly mounted on the side wall of the rotating connecting pipe along the radial direction thereof;

[0016] A row of openings is provided on the porous nozzle, and the arrangement direction of the openings is inclined at a certain angle to the axial direction of the porous nozzle. The inclination angle is preferably 3 to 15°, for example, 3°, 5°, 6°, 9°, 10°, 15°, etc.

[0017] When high-speed, high-pressure molten oligomers are sprayed through the multiple openings of the multi-hole nozzle, the opening pattern provided by the aforementioned structure can automatically activate the rotation mode using pressure, causing the multi-hole nozzle and the rotating connecting tube to rotate, forming a larger spray film, expanding the mist film area, and further improving the flash separation efficiency. On the one hand, the rotary atomizing nozzle forms a uniform film around the liquid, which is conducive to uniform atomization of the liquid, thereby improving the atomization and separation effects. On the other hand, the rotary atomizing nozzle generates a rotating flow, which increases the shear force of the liquid and helps to disperse the liquid into smaller particles. In addition, the rotary atomizing nozzle causes the droplets to continuously collide and split during rotation, increasing the frequency of particle collisions, which is conducive to the formation of smaller particles and improving the spray separation effect.

[0018] As a preferred technical solution of the present invention, there are 2 to 4 multi-hole nozzles, which can be symmetrically arranged in pairs on the rotating connecting tube, or 3 or 4 can be arranged at equal intervals on the rotating connecting tube.

[0019] As a preferred technical solution of the present invention, the rotary connecting pipe is rotatably connected to the outer sleeve via a ball bearing assembly provided in the outer sleeve, wherein the ball bearing assembly includes balls, limiting bolts, etc.;

[0020] And / or, an internal thread connector is installed in the outer sleeve to facilitate the installation and connection of the rotary atomizing nozzle.

[0021] As a preferred technical solution of the present invention, the polyolefin oligomer includes polyethylene wax.

[0022] As a preferred technical solution of the present invention, the internal temperature of the flash unit is controlled at 120-180°C. Preferably, the temperature is controlled at 130-170°C, for example, it can be 130°C, 135°C, 140°C, 145°C, 150°C, 155°C, 160°C, 165°C, 170°C, etc.

[0023] Compared with the prior art, the present invention has the following innovations and beneficial effects:

[0024] 1. After the molten polyolefin oligomer forms a mist film, the same mass of polyolefin oligomer exposes a larger specific surface area. During the flash evaporation process, the contact area of the polyolefin oligomer film increases, which promotes the heat and mass transfer process, making the distillation and separation more efficient and thorough, and helping to quickly achieve the separation of light and heavy components during the flash evaporation process;

[0025] 2. Since the spray membrane separation method can achieve efficient mass transfer at a relatively low temperature, it has low energy consumption and does not require the introduction of water vapor, reducing the water removal step, which helps to simplify the system structure and reduce production costs.

[0026] 3. The spray membrane separation method is simple to operate and has low requirements for operating parameter control. It can achieve precise control of the separation process by simply adjusting the conditions for spray film formation and parameters such as temperature and pressure during the flash evaporation process.

[0027] In summary, the utility model efficiently realizes the separation and purification of polyolefin oligomers including polyethylene wax through a spray membrane separation device. The molten pressurized polyolefin oligomers are formed into a liquid phase particle film through a spray mechanism, and enter the flash evaporation unit in the form of a spray film for rapid flash evaporation. The spray membrane separation method forms a film structure with a high specific surface area, improves mass transfer efficiency, accelerates evaporation speed, reduces energy consumption, is easy to control operation, has huge advantages, and greatly improves production efficiency. BRIEF DESCRIPTION OF THE DRAWINGS

[0028] Figure 1 This is a schematic structural diagram of the spray membrane separation device of the utility model;

[0029] Figure 2 This is a schematic structural diagram of a rotary atomizing nozzle used in a certain embodiment of the present utility model;

[0030] Figure 3 for Figure 2 Explosion diagram of

[0031] Figure 4 for Figure 2 Schematic cross-sectional view of ;

[0032] In the figure: 1-flash unit; 2-injection mechanism; 201-outer sleeve; 202-rotating connecting pipe; 203-porous nozzle; 2031-opening; 204-ball bearing assembly; 205-internal thread connector. DETAILED DESCRIPTION

[0033] The present invention is described in detail below. Any technical solutions not described in detail in the present invention are already disclosed in the art.

[0034] Reference Figure 1 The utility model provides a spray membrane separation device for separating polyolefin oligomers, comprising a flash unit 1 for flash-evaporating and separating light and heavy components of oligomers, and a spray mechanism 2 for forming molten oligomers into a spray film connected to the flash unit 1.

[0035] In a specific embodiment, the flash unit 1 includes a flash tank, preferably a vacuum flash tank. The spray mechanism 2 includes an atomizing nozzle or nozzle. The aperture of the atomizing nozzle or nozzle is selected based on the actual situation, for example, an atomizing nozzle or nozzle with an aperture of 1 to 10 mm is used. The aperture is determined based on the amount of material to be processed. A solid cone spray is preferably used to produce a circular impact area. Based on actual needs, the spray membrane separation device can be used in parallel or in series, and multiple spray mechanisms 2 can be installed as needed.

[0036] The utility model uses the spray membrane separation device to form a liquid phase particle film of molten pressurized polyolefin oligomers through the injection mechanism 2, and enters the flash evaporation unit 1 in the form of a spray film for rapid flash evaporation. The spray membrane separation method is used to form a film structure with a high specific surface area, thereby improving mass transfer efficiency, accelerating evaporation speed, reducing energy consumption, and being easy to control and operate. It has great advantages and greatly improves production efficiency.

[0037] As a more preferred embodiment of the present invention, the spray mechanism 2 adopts a rotary atomizing nozzle, which helps to increase the atomization efficiency, improve the atomization uniformity, enhance the liquid dispersion and reduce the particle size, and can effectively improve the spray separation effect.

[0038] Reference Figures 2-4 The rotary atomizing nozzle specifically includes an outer sleeve 201, a rotating connecting tube 202, and at least one porous nozzle 203. The rotating connecting tube 202 is rotatably connected to the outer sleeve 201 along the axial direction. The porous nozzle 203 is fixedly mounted on the side wall of the rotating connecting tube 202 along the radial direction. The porous nozzle 203 is provided with a row of openings 2031, and the arrangement direction of the openings 2031 is inclined at an angle of approximately 5° with the axial direction of the porous nozzle 203. There are two porous nozzles 203, which are symmetrically arranged in a pair on the rotating connecting tube 202. The rotating connecting tube 202 is rotatably connected to the outer sleeve 201 via a ball bearing assembly 204 disposed within the outer sleeve 201. The ball bearing assembly 204 includes a ball, a limit bolt, etc. An internal threaded connector 205 is installed within the outer sleeve 201 to facilitate the installation and connection of the rotary atomizing nozzle.

[0039] The above-mentioned rotary atomizing nozzle is installed in the middle position of the feed pipeline of the flash evaporation unit 1. When the high-speed and high-pressure molten oligomer is sprayed through the multiple openings 2031 of the porous nozzle 203, the openings 2031 of the structure can automatically open the rotation mode by using pressure, so that the porous nozzle 203 rotates together with the rotary connecting pipe 202, forming a large-scale spray film, expanding the mist film area, and improving the flash evaporation separation efficiency. The rotary atomizing nozzle forms a uniform film around the liquid, which is conducive to uniform atomization of the liquid, thereby improving the atomization effect and separation effect. The rotary atomizing nozzle also generates a rotary flow to increase the shear force of the liquid, which helps to disperse the liquid into smaller particles. In addition, the rotary atomizing nozzle causes the droplets to continuously collide and split during the rotation process, increasing the collision frequency of the particles, which is conducive to forming smaller particles and improving the spray separation effect.

[0040] As a preferred embodiment, the spray membrane separation device is used to separate polyethylene wax. The melted and pressurized polyethylene wax passes through a spray mechanism 2 to form a thin film of liquid particles. The polyethylene wax, in the form of a spray film, enters a flash evaporation unit 1 controlled at a temperature of 130-170°C for rapid flash evaporation. The high specific surface area of the spray film improves mass and heat transfer efficiency, accelerating the removal of the light polyethylene wax oil. The light and heavy components are discharged from the top and bottom of the flash evaporation unit 1, respectively, and each enters a subsequent processing unit for further processing, ultimately obtaining a refined product.

[0041] The above description of the embodiments is intended to facilitate understanding and use of the utility model by those skilled in the art. Those skilled in the art will readily be able to make various modifications to these embodiments and apply the general principles described herein to other embodiments without requiring inventive effort. Therefore, the utility model is not limited to the above-described embodiments. Improvements and modifications made by those skilled in the art based on the disclosure of this utility model without departing from the scope of this utility model should be within the scope of protection of this utility model.

Claims

1. A spray membrane separation device for separating polyolefin oligomers, comprising a flash unit (1) for flash-evaporating and separating light and heavy components of oligomers, characterized in that: The flash unit (1) is connected to a spray mechanism (2) for forming a spray film from the molten oligomer.

2. The spray membrane separation device for separating polyolefin oligomers according to claim 1, characterized in that: The flash unit (1) comprises a flash tank.

3. A spray membrane separation device for separating polyolefin oligomers according to claim 2, characterized in that: The flash tank is a vacuum flash tank.

4. The spray membrane separation device for separating polyolefin oligomers according to claim 1, characterized in that: The spraying mechanism (2) comprises an atomizing nozzle or a spray head.

5. The spray membrane separation device for separating polyolefin oligomers according to claim 4, characterized in that: The spraying mechanism (2) is a rotary atomizing nozzle.

6. The spray membrane separation device for separating polyolefin oligomers according to claim 5, characterized in that: The rotary atomizing nozzle comprises an outer sleeve (201), a rotary connecting pipe (202), and at least one porous nozzle (203). The rotating connecting tube (202) is rotatably connected to the outer sleeve (201) along the axial direction. The multi-hole nozzle (203) is fixedly mounted on the side wall of the rotating connecting pipe (202) along the radial direction thereof. A row of openings (2031) is provided on the multi-hole nozzle (203), and the arrangement direction of the openings (2031) is at a certain inclination angle with respect to the axial direction of the multi-hole nozzle (203).

7. A spray membrane separation device for separating polyolefin oligomers according to claim 6, characterized in that: There are 2 to 4 multi-hole nozzles (203) symmetrically arranged on the rotating connecting pipe (202).

8. The spray membrane separation device for separating polyolefin oligomers according to claim 6, characterized in that: The rotary connecting tube (202) is rotatably connected to the outer sleeve (201) via a ball bearing assembly (204) disposed within the outer sleeve (201); And / or, an internal threaded connector (205) is installed in the outer sleeve (201).

9. The spray membrane separation device for separating polyolefin oligomers according to claim 1, characterized in that: The internal temperature of the flash unit (1) is controlled to be 120-180°C.

Images