Circulating system applied to polyolefin elastomer

Abstract

The utility model discloses a circulation system applied to a polyolefin elastomer, and relates to the technical field of high polymer material production and processing, the circulation system comprises a devolatilization device and a separation device, the devolatilization device comprises a devolatilization chamber and a plurality of screws arranged in the devolatilization chamber, the plurality of screws are axially arranged side by side, the thread directions of the adjacent screws are opposite, and the threads are staggered; a plurality of vacuum ports are formed in the devolatilization chamber, and each vacuum port is connected with a vacuum pump, so that a vacuum section with a corresponding vacuum degree is formed in the devolatilization chamber, and corresponding volatile components are pumped out; the separation device comprises a rectifying tower, a plurality of temperature zones and a plurality of gas phase outlets are formed in the rectifying tower, and a corresponding separation temperature is set for each temperature zone; the reaction kettle is used for introducing a separated substance obtained by separation, and leading out a reaction product to a material inlet. According to the circulating system, the multistage vacuum extraction design is configured in the devolatilization device, and a polymer enters the devolatilization device and is subjected to devolatilization treatment under different vacuum degrees, so that quick removal of volatile components is ensured, and the devolatilization efficiency is improved.

Description

Technical Field

[0001] The utility model relates to the technical field of polymer material production and processing, in particular to a circulation system applied to polyolefin elastomers. Background Art

[0002] Polyolefin elastomer is a high-performance polyolefin with the characteristics of low density, large bending, high low-temperature impact resistance, easy processing, and reusability. At present, the largest application areas of polyolefin elastomers are the automotive industry and the wire and cable industry, mainly used to make pads, bumper covers, fender extensions, steering wheels, seats, hoses, insulation sheaths, and electrical molded parts.

[0003] Polyolefin elastomers can be produced using a slurry method, a solution method, and a gas phase method. In the process of using the gas phase method to produce polyolefin elastomers, the polymerization reaction will produce a certain amount of low molecular weight components, such as unreacted monomers, solvents and other volatiles. If these volatile organic compounds (VOCs) are not treated in time, they will not only reduce the quality of the final polymer, but also cause serious pollution to the environment. Therefore, the existing practice is generally to remove these volatile organic compounds (VOCs). However, these volatile organic compounds (VOCs) are essentially part of the production raw materials, and simply removing them will also cause a waste of production resources. Utility Model Content

[0004] The utility model aims to provide a circulation system applied to polyolefin elastomers, aiming to improve the devolatilization efficiency of production raw materials and realize the recovery and reuse of unreacted monomers and solvents generated in the production process, so as to solve the problem of waste of production resources existing in the prior art.

[0005] In order to achieve the above purpose, the utility model adopts the following technical solutions:

[0006] A circulation system for polyolefin elastomers, comprising a devolatilization device and a separation device, wherein:

[0007] The devolatilization device includes:

[0008] A shell, the shell forms a devolatilization chamber and has an inlet for introducing a polymer into the devolatilization chamber and an outlet for discharging a product after devolatilization of the polymer;

[0009] Multiple screws are arranged in the devolatilization chamber and arranged side by side axially from the feed inlet to the discharge outlet, and the threads of adjacent screws are in opposite directions and staggered;

[0010] A plurality of vacuum ports are formed in the devolatilization chamber and are arranged at intervals from the feed inlet to the discharge outlet; each vacuum port is connected to a vacuum pump to form a vacuum section of a corresponding vacuum degree in the devolatilization chamber to extract corresponding volatile components;

[0011] The separation device includes:

[0012] A distillation tower, wherein the distillation tower is provided with a distillation inlet for introducing volatile components recovered through the vacuum port;

[0013] Multiple temperature zones are formed in the distillation tower and arranged above the distillation inlet along the height direction of the distillation tower, and each temperature zone is set with a corresponding separation temperature;

[0014] A plurality of gas phase outlets are formed in the distillation tower and are respectively arranged in corresponding temperature zones to discharge the separated products separated from the volatile components;

[0015] The reactor is used to introduce the separated product obtained by separation, and the reaction product is led out to the feed inlet of the devolatilization device.

[0016] In some embodiments, the screw is provided with a shearing section arranged corresponding to the vacuum section, and a conveying section adjacent to the shearing section; along the direction from the feed port to the discharge port, the pitch and thread depth of the multiple shearing sections show a gradually decreasing trend, and the pitch and thread depth of the multiple conveying sections show a gradually decreasing trend.

[0017] In some embodiments, along the direction from the feed inlet to the discharge outlet, the pitch and thread depth of the same screw in the same shearing section tend to gradually decrease.

[0018] In some embodiments, along the direction from the feed inlet to the discharge outlet, the pitch and thread depth of the same screw in the same conveying section tend to gradually decrease.

[0019] In some embodiments, the devolatilization device further comprises:

[0020] The extractant adding component is arranged in the vacuum section to add the extractant to the polymer in the vacuum section.

[0021] In some embodiments, the separation device further comprises:

[0022] Multiple monomer storage tanks are respectively connected to corresponding gas phase outlets and connected to the reactor to transfer and store monomer separations.

[0023] In some embodiments, the separation device further comprises:

[0024] a condenser connected to the uppermost gas phase outlet to condense the separated material discharged from the uppermost gas phase outlet;

[0025] The solvent storage tank is connected to the condenser and the reaction kettle to transfer and store the liquid phase separation product.

[0026] In some embodiments, a disk or a filler is disposed in the temperature zone to increase the contact area between the volatile matter and the distillation steam.

[0027] Compared with the prior art, the circulation system for polyolefin elastomer in the embodiment of the utility model has the following beneficial effects:

[0028] (1) This circulation system adopts a multi-stage vacuum extraction design in the devolatilization device. The polymer enters the devolatilization device and is devolatilized at different vacuum levels to ensure the rapid removal of volatiles and improve the devolatilization efficiency.

[0029] (2) This circulation system recovers volatile components such as unreacted monomers and solvents through a devolatilization device, and separates and purifies the recovered volatile components through a distillation tower. The separated and purified monomers and solvents are reused in the production of polyolefin elastomers, thereby realizing the recycling of resources, reducing raw material consumption and waste emissions, and reducing production costs;

[0030] (3) This circulation system adopts a gradual screw structure, and the screw pitch and thread depth gradually decrease from the feed inlet to the discharge outlet, so that the molten polymer is subjected to different degrees of shear force and increasing pressure difference in different shear sections and conveying sections under the drive of the screw, thereby accelerating the removal of volatiles and effectively improving the devolatilization efficiency of the devolatilization device;

[0031] (4) This circulation system adds the extractant to the molten polymer through the extractant adding component, making the polymer more volatile. At the same time, since the extractant is incompatible with the polymer, tiny droplets will form in the polymer. When the solvent evaporates, these droplets will become bubble nuclei, thereby increasing the surface area of ​​the polymer for devolatilization, promoting mass transfer, and then taking away the volatile residues in the polymer. BRIEF DESCRIPTION OF THE DRAWINGS

[0032] Figure 1 is a schematic diagram of a circulation system in an embodiment of the utility model;

[0033] Figure 2 It is a schematic diagram of a screw in an embodiment of the utility model;

[0034] Figure 3 yes Figure 2 A partial enlarged view of middle A.

[0035] In the figure, 1. shell; 10. feed inlet; 11. discharge port; 13. vacuum port; 14. vacuum section; 2. screw; 20. first threaded body; 21. second threaded body; 22. shearing section; 23. conveying section; 3. distillation tower; 30. temperature zone; 31. gas phase outlet; 4. reactor; 5. monomer storage tank; 6. condenser; 7. solvent storage tank. DETAILED DESCRIPTION

[0036] The following is a further detailed description of the specific implementation of the present invention in conjunction with the accompanying drawings and examples. The following examples are used to illustrate the present invention, but are not intended to limit the scope of the present invention.

[0037] In the description of the present utility model, it should be understood that when an element is referred to as being "fixed to" or "disposed on" another element, it can be directly on the other element or indirectly on the other element. When an element is referred to as being "connected to" another element, it can be directly connected to the other element or indirectly connected to the other element. The terms "installed", "connected" and "connected" should be understood in a broad sense. For example, it can be a fixed connection, a detachable connection, or an integral connection; it can be a mechanical connection or an electrical connection; it can be a direct connection or an indirect connection through an intermediate medium, and it can be the internal connection of two elements or the interaction relationship between two elements. For those of ordinary skill in the art, the specific meanings of the above terms in the present utility model can be understood according to the specific circumstances.

[0038] In the description of the present invention, it should be understood that the terms "height", "up", "down", "vertical", "horizontal", "top", "bottom", "inside", "outside" and the like used in the present invention to indicate the orientation or position relationship are based on the orientation or position relationship shown in the accompanying drawings, and are only for the convenience of describing the present invention and simplifying the description, rather than indicating or implying that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and therefore cannot be understood as a limitation on the present invention.

[0039] In the description of the present invention, it should be understood that the terms "first" and "second" are used in the present invention for descriptive purposes only and cannot be understood as indicating or implying relative importance or implicitly indicating the number of the indicated technical features. Therefore, the features defined as "first" and "second" may explicitly or implicitly include one or more of the features.

[0040] Example

[0041] like Figure 1As shown, a circulation system applied to polyolefin elastomers according to an embodiment of the utility model comprises a devolatilization device and a separation device, wherein the devolatilization device is used to subject the internal polymer to devolatilization treatment and recover the volatiles generated during the devolatilization process, and the separation device is used to separate and purify the recovered volatiles so as to reuse the separated and purified monomers and solvents in the production of polyolefin elastomers, thereby realizing the recycling of resources.

[0042] In this embodiment, the devolatilization device comprises:

[0043] Shell 1, which forms a devolatilization chamber (not shown in the figure) and has an inlet 10 for introducing a polymer into the devolatilization chamber and an outlet 11 for discharging a product after devolatilization of the polymer;

[0044] A plurality of screws 2 are arranged in the devolatilization chamber, and along the direction from the feed inlet 10 to the discharge outlet 11, the plurality of screws 2 are axially arranged side by side, and the thread directions of adjacent screws 2 are opposite and the threads are staggered;

[0045] A plurality of vacuum ports 13 are formed in the devolatilization chamber and are arranged at intervals from the feed port 10 to the discharge port 11; each vacuum port 13 is connected to a vacuum pump (not shown in the figure) to form a vacuum section 14 of a corresponding vacuum degree in the devolatilization chamber to recover the corresponding volatile matter.

[0046] It should be noted that the staggered threads of adjacent screws 2 refer to that the threads of any screw 2 are arranged in correspondence with the pitch of the adjacent screw 2, and the threads of any screw 2 are embedded in the pitch of the adjacent screw 2. Moreover, along the direction from the feed port 10 to the discharge port 11, within a single pitch of any screw 2, the thread at the rear end is the first thread body 20, and within the pitch embedded in the first thread, the thread at the rear end is the second thread body 21. The first thread body 20 and the second thread body 21 are close to each other, so that when the polymer enters the staggered position of two adjacent screws 2, it can be sheared by the threads of the two adjacent screws 2, thereby accelerating the removal of volatiles.

[0047] As shown in the figure, in this embodiment, the screw 2 is provided with a shearing section 22 arranged corresponding to the vacuum section 14, and a conveying section 23 adjacent to the shearing section 22; along the direction from the feed inlet 10 to the discharge port 11, the pitch and thread depth of multiple shearing sections 22 show a gradually decreasing trend, and the pitch and thread depth of multiple conveying sections 23 show a gradually decreasing trend, and, along the direction from the feed inlet 10 to the discharge port 11, the pitch and thread depth of the same screw 2 in the same shearing section 22 show a gradually decreasing trend, and the pitch and thread depth of the same screw 2 in the same conveying section 23 show a gradually decreasing trend.

[0048] Based on the above design, the molten polymer will be subjected to different degrees of shear force in different shear sections 22 and conveying sections 23 under the transmission of the screw 2, and along the direction from the feed port 10 to the discharge port 11, as the pitch and thread depth of the screw 2 gradually decrease, the staggered positions of adjacent screws 2 will form a larger pressure difference, thereby accelerating the removal of volatile components of the polymer and more effectively improving the devolatilization efficiency of the devolatilization device.

[0049] In this embodiment, the devolatilization device further includes an extractant adding assembly (not shown in the figure), which is arranged in the vacuum section 14 to add the extractant to the polymer in the vacuum section 14. The extractant is added to the molten polymer through the extractant adding assembly to make the polymer more volatile. At the same time, since the extractant is incompatible with the polymer, tiny droplets will be formed in the polymer. When the solvent evaporates, these droplets will become bubble nuclei, thereby increasing the surface area of ​​the polymer devolatilization, promoting mass transfer, and then taking away the volatile residues in the polymer.

[0050] In this embodiment, the separation device includes:

[0051] A distillation tower 3, wherein the distillation tower 3 is provided with a distillation inlet for introducing volatile components recovered through the vacuum port 13;

[0052] A plurality of temperature zones 30 are formed in the distillation tower 3 and arranged above the distillation inlet along the height direction of the distillation tower 3. Each temperature zone 30 is set with a corresponding separation temperature. A disk or filler is also arranged in the temperature zone 30 to increase the contact area between the volatile matter and the distillation steam.

[0053] A plurality of gas phase outlets 31 are formed in the distillation tower 3 and are respectively arranged in the corresponding temperature zones 30 to discharge the separated products separated from the volatile components;

[0054] The reactor 4 is used to introduce the separated material in the monomer storage tank 5 or the solvent storage tank 7, and to guide the reaction product to the inlet 10 of the devolatilization device.

[0055] It should be noted that the separation temperature of the temperature zone 30 can be set according to the composition of the volatile matter generated by the polymer during the devolatilization process. Generally speaking, the separation temperatures of multiple temperature zones 30 are arranged to gradually decrease from top to bottom along the height direction of the distillation tower 3. The unreacted monomers with lower separation temperatures will be separated first and discharged from the distillation tower 3 from the gas phase outlet 31 closer to the distillation inlet. The components that cannot be separated after multiple temperature zones 30 will be discharged from the distillation tower 3 from the top gas phase outlet 31.

[0056] In this embodiment, the separation device further includes:

[0057] A plurality of monomer storage tanks 5, each of which is connected to the corresponding gas phase outlet 31 and to the reactor 4 to transfer and store the monomer separation;

[0058] A condenser 6, the condenser 6 is connected to the uppermost gas phase outlet 31 to condense the separated material discharged from the uppermost gas phase outlet 31;

[0059] The solvent storage tank 7 is connected to the condenser 6 and the reaction kettle 4 to transfer and store the liquid phase separation product.

[0060] It should be noted that the gas phase outlet 31 connected to the monomer storage tank 5 is generally the outlet of the unreacted monomers gradually separated from the recovered volatiles, so what is transferred and stored in each monomer storage tank 5 is a single-component, gas-phase monomer separation. A valve body can be set at the inlet and outlet of the monomer storage tank 5, so that the operator can introduce the required monomer separation into the reactor 4 for treatment according to the process requirements and reuse it for production.

[0061] In addition, valve bodies may also be provided at the inlet and outlet of the solvent storage tank 7 so that the operator can introduce the required liquid phase separation product into the reactor 4 for treatment according to process requirements and reuse it for production.

[0062] Based on the above structure, the working process of the circulation system of this embodiment is as follows:

[0063] The polymer enters the devolatilization chamber through the feed port 10 and is transported from the feed port 10 to the discharge port 11 by the screw 2. During the transport process, the polymer reciprocates through the shearing section 22 and the conveying section 23 of the screw 2, and is subjected to different degrees of shearing force in different shearing sections 22 and conveying sections 23. In addition, in the shearing section 22, the vacuum section 14 formed by the vacuum pump is used to remove the volatile matter of the polymer and then the polymer is drawn out of the devolatilization chamber through the vacuum port 13.

[0064] The volatile matter recovered through the vacuum port 13 enters the distillation tower 3 through the distillation inlet. At this time, the volatile matter is a gas phase substance, and the volatile matter will rise in the distillation tower 3 along the height direction of the distillation tower 3. In this process, the volatile matter will pass through the temperature zones 30 with different separation temperatures in sequence, and the discs or fillers set in the temperature zones 30 will make the components corresponding to the separation temperature in the volatile matter be discharged through the corresponding gas phase outlet 31 to the monomer storage tank 5 for temporary storage, and the components that cannot be separated after passing through multiple temperature zones 30 will be discharged from the distillation tower 3 from the top gas phase outlet 31, condensed by the condenser 6, and then enter the solvent storage tank 7 for temporary storage.

[0065] According to the production process requirements, the substances temporarily stored in the monomer storage tank 5 or the solvent storage tank 7 are sequentially introduced into the reactor 4, and after the reaction in the reactor 4, they are guided to the feed port 10 of the devolatilization device and reused in production.

[0066] In summary, the embodiment of the utility model provides a circulation system for polyolefin elastomers, which configures a multi-stage vacuum extraction design in the devolatilization device, and the polymer enters the devolatilization device and undergoes devolatilization treatment at different vacuum degrees to ensure the rapid removal of volatiles and improve the devolatilization efficiency; and, the circulation system recovers volatiles such as unreacted monomers and solvents through the devolatilization device, and separates and purifies the recovered volatiles through the distillation tower 3, and the separated and purified monomers and solvents are reused in the production of polyolefin elastomers, thereby realizing the recycling of resources, reducing raw material consumption and waste emissions, and reducing production costs; in addition, the circulation system adopts a gradual screw 2 structure from the feed inlet 10 to In the direction of the discharge port 11, the pitch and thread depth of the screw 2 show a gradually decreasing trend, so that the molten polymer is subjected to different degrees of shear force and increasing pressure difference in different shear sections 22 and conveying sections 23 under the drive of the screw 2, thereby accelerating the removal of volatiles and effectively improving the devolatilization efficiency of the devolatilization device; moreover, the circulation system adds the extractant to the molten polymer through the extractant adding component to make the polymer more volatile. At the same time, since the extractant is incompatible with the polymer, tiny droplets will be formed in the polymer. When the solvent evaporates, these droplets will become bubble nuclei, thereby increasing the surface area of ​​the polymer devolatilization, promoting mass transfer, and then taking away the volatile residues in the polymer.

[0067] The above is only a preferred embodiment of the present invention. It should be pointed out that for ordinary technicians in this technical field, several improvements and substitutions can be made without departing from the technical principle of the present invention. These improvements and substitutions should also be regarded as the protection scope of the present invention.

Claims

1. A circulation system for polyolefin elastomers, characterized in that: It includes a devolatilization device and a separation device, wherein: The devolatilization device comprises: A shell, the shell forming a devolatilization chamber and having an inlet for introducing a polymer into the devolatilization chamber and an outlet for discharging a product after devolatilization of the polymer; A plurality of screws, wherein the plurality of screws are arranged in the devolatilization chamber and are axially arranged side by side along the direction from the feed inlet to the discharge outlet, and the threads of adjacent screws are in opposite directions and staggered; A plurality of vacuum ports are formed in the devolatilization chamber and are arranged at intervals from the feed inlet to the discharge outlet; each vacuum port is connected to a vacuum pump to form a vacuum section of a corresponding vacuum degree in the devolatilization chamber to extract corresponding volatile components; The separation device comprises: a distillation tower, wherein the distillation tower is provided with a distillation inlet for introducing the volatile matter recovered through the vacuum port; A plurality of temperature zones, wherein the plurality of temperature zones are formed in the distillation tower and arranged above the distillation inlet along the height direction of the distillation tower, and each temperature zone is set with a corresponding separation temperature; A plurality of gas phase outlets are formed in the distillation tower and are respectively arranged in corresponding temperature zones to discharge the separated products separated from the volatile components; A reactor is provided for introducing the separated product obtained by separation into the reactor, and the reaction product is guided out to the feed inlet.

2. The circulation system according to claim 1, characterized in that: The screw is provided with a shearing section arranged corresponding to the vacuum section, and a conveying section adjacent to the shearing section; along the direction from the feed port to the discharge port, the pitch and thread depth of the multiple shearing sections show a gradually decreasing trend, and the pitch and thread depth of the multiple conveying sections show a gradually decreasing trend.

3. The circulation system according to claim 2, characterized in that: Along the direction from the feed inlet to the discharge outlet, the pitch and thread depth of the same screw in the same shearing section show a gradually decreasing trend.

4. The circulation system according to claim 2, characterized in that: Along the direction from the feed inlet to the discharge outlet, the pitch and thread depth of the same screw in the same conveying section show a gradually decreasing trend.

5. The circulation system according to claim 1, characterized in that: The devolatilization device also includes: The extractant adding component is arranged in the vacuum section to add the extractant to the polymer in the vacuum section.

6. The circulation system according to claim 1, characterized in that: The separation device also includes: A plurality of monomer storage tanks are respectively connected to corresponding gas phase outlets and to the reactor to transfer and store monomer separations.

7. The circulation system according to claim 1, characterized in that: The separation device also includes: a condenser connected to the uppermost gas phase outlet to condense the separated material discharged from the uppermost gas phase outlet; A solvent storage tank is connected to the condenser and the reactor to transfer and store the liquid phase separation product.

8. The circulation system according to claim 1, characterized in that: Disks or fillers are arranged in the temperature zone to increase the contact area between the volatile matter and the distillation steam.

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