Separation method and separation device for polyolefin elastomer solution

Abstract

The invention provides a separation method and a separation device for a polyolefin elastomer solution. The separation method is carried out through the separation device comprising a first-stage flash evaporator, a second-stage flash evaporator, a pre-separation tower, an ethylene recovery tower, a solvent recovery tower, a grease separation tower, a first-stage comonomer recovery tower and a second-stage comonomer recovery tower. According to the invention, the polyolefin elastomer, ethylene, solvent, oligomer grease, comonomer and isomer of the comonomer in the polyolefin elastomer solution can be separated respectively, and the energy consumption can be reduced.

Description

Technical Field

[0001] This invention relates to a method and apparatus for separating polyolefin elastomer solutions, belonging to the field of polyolefin elastomer technology. Background Technology

[0002] Polyolefin elastomers (POEs) are polyolefin materials copolymerized from ethylene and propylene or other α-olefins (such as 1-hexene, 1-octene, etc.). The molecular chains of polyolefin elastomers contain both crystalline segments of polyethylene and amorphous regions formed by the random copolymerization of ethylene and α-olefins. At room temperature, polyolefin elastomers exhibit the high elasticity of rubber; at temperatures above the melting temperature of polyethylene segments, they can undergo plastic flow. Polyolefin elastomers are thermoplastic elastomers with excellent aging resistance, corrosion resistance, heat resistance, and water vapor phase resistance, and are widely used in automotive parts, wires and cables, machine tools, and household goods.

[0003] ExxonMobil's gas-phase polymerization process (EXPOL process) and DowDuPont's solution polymerization process (Insite process) are both typical production processes for polyolefin elastomers. Among them, the solution method is a commonly used industrial process for producing polyolefin elastomers. The catalysts used are generally metallocene catalysts, and the solvents used are generally alkanes or aromatics that can effectively dissolve the polymer and are easy to separate and recover in subsequent processes. For example, patent document CN202210751567 discloses a solution polymerization preparation method for ethylene and α-olefin copolymers. The polymerization process uses an adiabatic reactor. Ethylene, α-olefin and solvent are mixed and the temperature is adjusted in the feeding unit to obtain a reaction feed stream. This stream is sent to the solution polymerization reaction unit. Under the action of a catalyst, a solution containing polymers of ethylene and α-olefins is obtained. Subsequently, through the separation and recovery unit, a circulating stream containing unreacted ethylene, α-olefin and solvent, as well as polymer products, are obtained. However, this solution polymerization preparation method is a traditional solution polymerization separation process, which involves multiple heat exchangers and flash evaporators, and finally the product is obtained through an extruder. The process is complex, energy-intensive and requires high investment.

[0004] Solution polymerization offers a favorable environment for reaction, heat transfer, and mass transfer, providing significant advantages in the production of polyolefin elastomers. However, it also has some notable drawbacks, one of which is the complexity of subsequent separation processes. Specifically, after the polyolefin elastomer (polymer) synthesis reaction is completed, the polymer in the solution must be separated from the solvent to obtain a pure polymer (product). However, this separation process presents several challenges: First, the separation process is energy-intensive, as solvent recovery typically requires energy-intensive operations such as distillation. Subsequent devolatilization and distillation processes account for over 60% of the total energy consumption of the entire process, significantly increasing production costs and greenhouse gas emissions. Second, the separation process requires specialized equipment and processes, resulting in large equipment demands and high investment and operating costs.

[0005] Therefore, developing an energy-efficient separation method is crucial for reducing energy consumption and production costs, as well as greenhouse gas emissions. Summary of the Invention

[0006] This invention provides a method and apparatus for separating polyolefin elastomer solutions, which can efficiently and energy-savingly separate polyolefin elastomers, ethylene, solvents, oligomeric oils, comonomers, and isomers of comonomers from polyolefin elastomer solutions. By effectively recovering system energy, it reduces process energy consumption, reduces the amount of heating medium used, reduces production costs, and reduces greenhouse gas emissions. The equipment used has a high degree of integration, which helps to reduce equipment investment and operating costs and save equipment space.

[0007] This invention provides a method for separating a polyolefin elastomer solution. The separation method employs a separation apparatus comprising a primary flash evaporator, a secondary flash evaporator, a pre-separation tower, an ethylene recovery tower, a solvent recovery tower, an oil separation tower, a primary comonomer recovery tower, and a secondary comonomer recovery tower. The polyolefin elastomer solution comprises polyolefin elastomer, ethylene, solvent, oligomeric oils, comonomers, and isomers of the comonomers. The separation method includes: the polyolefin elastomer solution entering the primary flash evaporator for a first separation to obtain a first volatile component and a first concentrated phase; the first concentrated phase entering the secondary flash evaporator... A second separation occurs in the evaporator, yielding a second volatile component and a second concentrated phase containing polyolefin elastomer; the first volatile component exchanges heat with a cooling medium flowing through a first heat exchanger, yielding a cooled first volatile component and steam formed by the cooling medium; the cooled first volatile component enters the pre-separation tower; the steam is used to provide a heat source for the ethylene recovery tower; the second volatile component, after being cooled to a liquid state, exchanges heat with a hot component flowing through a second heat exchanger, yielding a preheated second volatile component, which enters the pre-separation tower and reacts with the... The cooled first volatile component undergoes a third separation after mixing, yielding a first light component and a first heavy component. The first light component enters the ethylene recovery tower for a fourth separation, yielding a second light component and a second heavy component containing ethylene. The second heavy component is returned to the pre-separation tower for a repeat of the third separation. The first heavy component enters the solvent recovery tower for a fifth separation, yielding a third light component and a third heavy component containing solvent. The third light component containing solvent is cooled to obtain a cooled third light component, and the hot component flowing through the second heat exchanger includes the cooled third light component. The third heavy component enters the oil separation tower for a sixth separation, yielding a fourth light component, an intermediate component, and a fourth heavy component containing oligomer oils. The fourth light component is returned to the solvent recovery tower for a repeat of the fifth separation. The intermediate component enters the primary comonomer recovery tower for a seventh separation, yielding a fifth light component and a fifth heavy component containing isomers of the comonomer. The fifth light component enters the secondary comonomer recovery tower for an eighth separation, yielding a sixth light component and a sixth heavy component containing the comonomer. The sixth heavy component is returned to the primary comonomer recovery tower for a repeat of the seventh separation.

[0008] Optionally, the third light component containing solvent recovers a first heat by passing through the first reboiler of the solvent recovery tower, and the recovered first heat is used for the fifth separation, while obtaining a cooled third light component; and / or, the sixth light component recovers a second heat by passing through the reboiler of the primary comonomer recovery tower, and the recovered second heat is used for the seventh separation, while obtaining a cooled sixth light component; and / or, the boiling point of the solvent is lower than the boiling point of the comonomer and the isomerized form of the comonomer.

[0009] Optionally, the process of recovering first heat from the third light component containing solvent via the first reboiler of the solvent recovery tower, and using the recovered first heat for the fifth separation, while obtaining a cooled third light component, includes: the third light component containing solvent being pressurized and heated by a first heat pump, then recovering first heat via the first reboiler of the solvent recovery tower, and using the recovered first heat for the fifth separation, while obtaining a cooled third light component; wherein, the cooled third light component is sequentially depressurized by a third pressure reducing valve and cooled by a fourth condenser before entering the top reflux tank of the solvent recovery tower to complete the solvent separation; and / or, the sixth light component containing comonomer flows through the reboiler of the primary comonomer recovery tower to recover second heat, and the recovered second heat is used for the seventh separation, while obtaining a cooled sixth light component containing comonomer; the cooled sixth light component containing comonomer is then cooled by a sixth condenser to complete the separation of the comonomer.

[0010] Optionally, the process of the polyolefin elastomer solution undergoing first separation in the primary flash evaporator to obtain a first volatile component and a first concentrated phase includes: adjusting the pressure of the polyolefin elastomer solution to 6-10 MPa, preheating it to 250-300°C via a solution preheater, then depressurizing it via a first pressure reducing valve, and then entering the primary flash evaporator for the first separation to obtain the first volatile component and the first concentrated phase; and / or, the process of the first concentrated phase entering the secondary flash evaporator for second separation to obtain a second volatile component and a second concentrated phase containing polyolefin elastomer includes: the first concentrated phase being depressurized via a second pressure reducing valve, then entering the secondary flash evaporator for the second separation to obtain a second volatile component and a second concentrated phase containing polyolefin elastomer. The second concentrated phase; and / or, the second volatile component, after being cooled to a liquid state, exchanges heat with the hot component flowing through the second heat exchanger to obtain a preheated second volatile component, the preheated second volatile component entering the pre-separation tower, mixing with the cooled first volatile component entering the pre-separation tower and undergoing a third separation to obtain a first light component and a first heavy component, comprising: the second volatile component being cooled to a liquid state by a first condenser, the liquid being transported to the second heat exchanger by a first pressurizing pump, exchanging heat with the cooled third light component flowing through the second heat exchanger to obtain a preheated second volatile component; the preheated second volatile component entering the pre-separation tower, mixing with the cooled first volatile component entering the pre-separation tower and undergoing a third separation. The process of obtaining a first light component and a first heavy component includes: the logarithmic mean temperature difference between the cold-side feed and the hot-side feed of the second heat exchanger is 10-30°C; and / or, the first light component enters the ethylene recovery tower for the fourth separation to obtain the second light component and the second heavy component containing ethylene. This process includes: the first light component is cooled by a second condenser, enters a first condenser reflux tank and mixes with butene entering the first condenser reflux tank, then enters the ethylene recovery tower for the fourth separation to obtain the second light component and the second heavy component containing ethylene; wherein, in the first condenser reflux tank, the molar ratio of butene to ethylene in the first light component is (5-15):1; and / or, the first light component contains ethylene... The second light component of the ethylene is cooled by the third condenser and then enters the second condenser reflux tank to complete the separation of the ethylene; and / or, the process of returning the fourth light component to the solvent recovery tower to repeat the fifth separation includes: the fourth light component is cooled by the fifth condenser and then enters the third condenser reflux tank, and then is transported to the solvent recovery tower by the third pressurization pump to repeat the fifth separation; and / or, the process of the fifth light component entering the secondary comonomer recovery tower to undergo the eighth separation, obtaining a sixth light component and a sixth heavy component containing comonomer includes: the fifth light component is pressurized and heated by the second heat pump and then enters the secondary comonomer recovery tower to undergo the eighth separation, obtaining a sixth light component and a sixth heavy component containing comonomer;And / or, the process of returning the sixth heavy component to the primary comonomer recovery tower to repeat the seventh separation includes: the sixth heavy component being depressurized by the fourth pressure reducing valve and then returned to the primary comonomer recovery tower to repeat the seventh separation.

[0011] Optionally, the pressure in the primary flash evaporator is 2.0–4.0 MPa; and / or, the pressure in the secondary flash evaporator is 0.2–0.5 MPa; and / or, the pressure of the saturated steam is 1.2–1.5 MPa; and / or, the pressure in the pre-separation tower is 1.8–2.4 MPa; and / or, the pressure in the ethylene recovery tower is 1.6–2.2 MPa; and / or, the pressure in the solvent recovery tower is 500–800 kPa; and / or, the pressure in the oil separation tower is 300–500 kPa; and / or, the pressure in the primary comonomer recovery tower is 50–150 kPa; and / or, the pressure in the secondary comonomer recovery tower is 200–400 kPa; and / or, the pressure difference between the primary and secondary comonomer recovery towers is 100–300 kPa.

[0012] This invention also provides a separation device for a polyolefin elastomer solution, comprising: a primary flash evaporator having a material inlet, a first volatile component outlet, and a first concentrated phase outlet; a first heat exchanger having a first cold-side inlet, a first cold-side outlet, a first hot-side outlet, and a first hot-side inlet connected to the first volatile component outlet of the primary flash evaporator; a secondary flash evaporator having a second volatile component outlet, a second concentrated phase outlet, and a first concentrated phase inlet connected to the first concentrated phase outlet of the primary flash evaporator; a pre-separation tower having a first light component outlet, a first heavy component outlet, a first top reflux inlet, a first bottom reflux inlet, and a volatile component inlet, wherein the volatile component inlet is connected to the first cold-side outlet of the first heat exchanger, and the volatile component inlet is connected to the second volatile component outlet of the secondary flash evaporator; an ethylene recovery tower having a second light component outlet, a second top reflux inlet, a second bottom reflux inlet, a second heavy component outlet connected to the first top inlet of the pre-separation tower, and a first light component inlet connected to the first light component outlet of the pre-separation tower; and a solvent recovery tower having... The oil and fat separation tower is provided with an intermediate component outlet, a fourth heavy component outlet, a fourth top reflux inlet, a fourth bottom reflux inlet, a third heavy component inlet connected to the third heavy component outlet, and a first heavy component inlet connected to the first heavy component outlet of the pre-separation tower; the oil and fat separation tower is provided with an intermediate component outlet, a fourth heavy component outlet, a fourth top reflux inlet, a fourth bottom reflux inlet, a third heavy component inlet connected to the third heavy component outlet of the solvent recovery tower, and a fourth light component outlet connected to the fourth light component inlet of the solvent recovery tower; the primary copolymer monomer recovery tower is provided with a fifth heavy component outlet, a fifth light component outlet, a fifth bottom reflux inlet, a sixth heavy component inlet, and an intermediate component inlet connected to the intermediate component outlet of the oil and fat separation tower; the secondary copolymer monomer recovery tower is provided with a sixth top reflux inlet, a sixth light component outlet connected to the reboiler of the primary copolymer monomer recovery tower, a fifth light component inlet connected to the fifth light component outlet of the primary copolymer monomer recovery tower, and a sixth heavy component outlet connected to the sixth heavy component inlet of the primary copolymer monomer recovery tower.

[0013] Optionally, it further includes: a solution preheater, having a solution inlet and a material outlet communicating with the material inlet of the first-stage flash evaporator; wherein a first pressure reducing valve is provided between the material outlet of the solution preheater and the material inlet of the first-stage flash evaporator; and / or, a second pressure reducing valve, provided between the first concentrated phase outlet of the first-stage flash evaporator and the first concentrated phase inlet of the second-stage flash evaporator; and / or, a second heat exchanger, having a second cold-side inlet communicating with the second volatile component outlet of the second-stage flash evaporator, a second cold-side outlet communicating with the volatile component inlet of the pre-separation tower, a second hot-side inlet communicating with the reboiler of the solvent separation tower, and a second hot-side outlet; a first condenser and a first pressurizing pump, along the direction of the material flow, wherein... The first condenser and the first pressurizing pump are sequentially located between the second volatile component outlet of the secondary flash evaporator and the second cold-side inlet of the second heat exchanger; the third pressure reducing valve and the fourth condenser are sequentially located between the reboiler of the solvent separation tower and the second hot-side inlet of the second heat exchanger; and / or, the second condenser and the first condenser reflux tank are sequentially located between the first light component outlet of the pre-separation tower and the first light component inlet of the ethylene recovery tower, along the direction of the flow. The first condenser reflux tank is further provided with a first reflux outlet communicating with the first top reflux inlet of the pre-separation tower, a butene inlet, and a second heavy component outlet communicating with the ethylene recovery tower. An inlet connected to the outlet; a second pressurizing pump, located between the inlet of the second heavy component of the ethylene recovery tower and the inlet of the first condenser reflux tank; and / or, a third condenser and a second condenser reflux tank, arranged sequentially between the outlet of the second light component of the ethylene recovery tower and the second top reflux inlet of the ethylene recovery tower, along the direction of the flow; wherein the second condenser reflux tank is also provided with an ethylene outlet; and / or, a first heat pump, located between the outlet of the third light component of the solvent recovery tower and the first reboiler of the solvent recovery tower; and / or, the first reboiler of the solvent recovery tower, located in the middle of the solvent recovery tower, the solvent recovery tower including a second reboiler located at the bottom. A boiling vessel; and / or a fifth condenser, a third condenser reflux tank, and a third pressurizing pump, arranged sequentially between the fourth light component outlet of the grease separation tower and the fourth light component inlet of the solvent recovery tower, along the direction of the material flow; wherein the third condenser reflux tank is also provided with an outlet communicating with the fourth top reflux inlet of the grease separation tower; and / or a second heat pump, arranged between the fifth light component outlet of the primary copolymer monomer recovery tower and the fifth light component inlet of the secondary copolymer monomer recovery tower; and / or a fourth pressure reducing valve, arranged between the sixth heavy component outlet of the secondary copolymer monomer recovery tower and the sixth heavy component inlet of the primary copolymer monomer recovery tower.

[0014] Optionally, the distance between the material inlet of the first-stage flash evaporator and the top of the first-stage flash evaporator is one-quarter to one-half of the height of the first-stage flash evaporator; and / or, the first volatile component outlet of the first-stage flash evaporator is located at the top of the first-stage flash evaporator; and / or, the first concentrated phase outlet of the first-stage flash evaporator is located at the bottom of the first-stage flash evaporator; and / or, the distance between the first concentrated phase inlet of the second-stage flash evaporator and the top of the second-stage flash evaporator is one-quarter to one-half of the height of the second-stage flash evaporator; and / or, the second volatile component outlet of the second-stage flash evaporator is located at the top of the second-stage flash evaporator; and / or, the distance between the first concentrated phase inlet of the second-stage flash evaporator and the top of the second-stage flash evaporator is one-quarter to one-half of the height ... The second concentrated phase outlet of the evaporator is located at the bottom of the secondary flash evaporator; and / or, the volatile component inlet of the pre-separation tower is located in the middle of the pre-separation tower; and / or, the first light component outlet of the pre-separation tower is located at the top of the pre-separation tower; and / or, the first heavy component outlet of the pre-separation tower is located at the bottom of the pre-separation tower; and / or, the first light component inlet of the ethylene recovery tower is located in the middle of the ethylene recovery tower; and / or, the second light component outlet of the ethylene recovery tower is located at the top of the ethylene recovery tower; and / or, the second heavy component outlet of the ethylene recovery tower is located at the bottom of the ethylene recovery tower; and / or, the first heavy component inlet of the solvent recovery tower is located in the middle of the solvent recovery tower; and / Or, the third light component outlet of the solvent recovery tower is located at the top of the solvent recovery tower; and / or, the third heavy component outlet of the solvent recovery tower is located at the bottom of the solvent recovery tower; and / or, the fourth light component inlet of the solvent recovery tower is located at the bottom of the solvent recovery tower; and / or, the fourth light component outlet of the oil separation tower is located at the top of the oil separation tower; and / or, the third heavy component inlet of the oil separation tower is located in the middle of the oil separation tower; and / or, the intermediate component outlet of the oil separation tower is located in the middle of the oil separation tower and on the side away from the third heavy component inlet; and / or, the fourth heavy component outlet of the oil separation tower is located at the bottom of the oil separation tower; And / or, the intermediate component inlet of the primary comonomer recovery tower is located at the top of the primary comonomer recovery tower; and / or, the fifth light component outlet of the primary comonomer recovery tower is located at the top of the primary comonomer recovery tower; and / or, the fifth heavy component outlet of the primary comonomer recovery tower is located at the bottom of the primary comonomer recovery tower; and / or, the sixth heavy component inlet of the primary comonomer recovery tower is located at the top of the primary comonomer recovery tower; and / or, the sixth light component outlet of the secondary comonomer recovery tower is located at the top of the secondary comonomer recovery tower; and / or, the fifth light component inlet and outlet of the secondary comonomer recovery tower are located at the bottom of the secondary comonomer recovery tower;And / or, the sixth heavy component outlet of the secondary copolymer recovery tower is located at the bottom of the secondary copolymer recovery tower.

[0015] Optionally, the oil separation tower is provided with a partition in the middle, which divides the internal space of the oil separation tower into two regions along the axial direction of the oil separation tower. The middle part of the two regions is not connected, the top of the two regions is connected, and the bottom of the two regions is connected. The third component inlet and the intermediate component outlet of the oil separation tower are respectively located on the side wall corresponding to the middle part of the two regions.

[0016] Optionally, the cooling medium of the first condenser includes water; and / or, the cooling medium of the second condenser includes water; and / or, the cooling medium of the third condenser includes liquid ammonia; and / or, the cooling medium of the fourth condenser includes water; and / or, the cooling medium of the fifth condenser includes water.

[0017] This invention provides a method and apparatus for separating polyolefin elastomer solutions, which can efficiently and energy-savingly separate polyolefin elastomers, ethylene, solvents, oligomeric oils, comonomers, and isomers of comonomers from polyolefin elastomer solutions. By effectively recovering system energy, it reduces process energy consumption, reduces the amount of heating medium used, reduces production costs, and reduces greenhouse gas emissions. The equipment used has a high degree of integration, which helps to reduce equipment investment and operating costs and save equipment space. Attached Figure Description

[0018] Figure 1 This is a schematic diagram of the separation device for the polyolefin elastomer solution in Example 1;

[0019] Figure 2 This is a schematic diagram of the separation device for the polyolefin elastomer solution in Comparative Example 1.

[0020] Explanation of reference numerals in the attached figures:

[0021] E1 - Solution preheater, V1 - Primary flash evaporator, V2 - Secondary flash evaporator, T1 - Pre-separation tower, T2 - Ethylene recovery tower, T3 - Solvent recovery tower, T4 - Oil and fat separation tower, T5 - Primary comonomer recovery tower, T6 - Secondary comonomer recovery tower, E2 - First heat exchanger, E3 - First condenser, E4 - Second heat exchanger, POE - Polyolefin elastomer, A - Ethylene, B - Butene, C - Solvent, D - Oligomer oil and fat, E - Comonomer, F - Comonomer isomer. Detailed Implementation

[0022] To make the objectives, technical solutions, and advantages of this invention clearer, the technical solutions in the embodiments of this invention will be clearly and completely described below in conjunction with the embodiments of this invention. Obviously, the described embodiments are only some embodiments of this invention, not all embodiments. Based on the embodiments of this invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of this invention.

[0023] This invention provides a method for separating a polyolefin elastomer solution. The method employs a separation apparatus including a primary flash evaporator, a secondary flash evaporator, a pre-separation tower, an ethylene recovery tower, a solvent recovery tower, an oil separation tower, a primary comonomer recovery tower, and a secondary comonomer recovery tower. The polyolefin elastomer solution comprises polyolefin elastomer, ethylene, solvent, oligomeric oils, comonomers, and isomers of the comonomers. The separation method includes: the polyolefin elastomer solution entering the primary flash evaporator for a first separation to obtain a first volatile component and a first concentrated phase; the second... A concentrated phase enters a secondary flash evaporator for a second separation, yielding a second volatile component and a second concentrated phase containing polyolefin elastomer. The first volatile component, after heat exchange with a cooling medium flowing through a first heat exchanger, yields a cooled first volatile component and vapor formed from the cooling medium. The cooled first volatile component enters a pre-separation tower; the vapor is used to provide a heat source for the ethylene recovery tower. The second volatile component, after being cooled to a liquid state, exchanges heat with a hot component flowing through a second heat exchanger, yielding a preheated second volatile component. The preheated second volatile component enters the pre-separation tower and, together with the... The first volatile component cooled in the pre-separation tower undergoes a third separation after mixing, yielding a first light component and a first heavy component. The first light component enters the ethylene recovery tower for a fourth separation, yielding a second light component and a second heavy component containing ethylene. The second heavy component is returned to the pre-separation tower for a repeat of the third separation. The first heavy component enters the solvent recovery tower for a fifth separation, yielding a third light component containing solvent and a third heavy component. The third light component containing solvent is cooled to obtain a cooled third light component, and the hot component flowing through the second heat exchanger includes the cooled third light component. The third heavy component enters the grease separation tower for a sixth separation, yielding a fourth light component, an intermediate component, and a fourth heavy component containing oligomer grease. The fourth light component is returned to the solvent recovery tower for a repeat of the fifth separation. The intermediate component enters the primary comonomer recovery tower for a seventh separation, yielding a fifth light component and a fifth heavy component containing isomers of the comonomer. The fifth light component enters the secondary comonomer recovery tower for an eighth separation, yielding a sixth light component containing comonomer and a sixth heavy component. The sixth heavy component is returned to the primary comonomer recovery tower for a repeat of the seventh separation.

[0024] According to the inventor's research and analysis: First, the separation method employs a separation device including a primary flash evaporator, a secondary flash evaporator, a pre-separation tower, an ethylene recovery tower, a solvent recovery tower, an oil separation tower, a primary comonomer recovery tower, and a secondary comonomer recovery tower. This device can efficiently separate components such as polyolefin elastomer, ethylene, solvent, oligomeric oils, comonomers, and comonomer isomers from the polyolefin elastomer solution. Furthermore, the separation device has a high degree of equipment integration, which helps reduce equipment investment and operating costs, and saves equipment space. Second, due to the large temperature difference between the various streams in the separation process, the use of thermal integration technology can fully recover and utilize the energy within the system. For example, the first volatile component has high heat (energy). After heat exchange in the first heat exchanger, the heat of the first volatile component is transferred to the cooling liquid to form steam. This steam is used to provide a heat source for the ethylene recovery tower, reducing the amount of heating medium used in the ethylene recovery tower and achieving good energy-saving effects. This helps reduce process energy consumption, production costs, and greenhouse gas emissions.

[0025] Therefore, the separation method for polyolefin elastomer solutions provided in this embodiment of the invention can efficiently and energy-savingly separate polyolefin elastomers, ethylene, solvents, oligomeric oils, comonomers, and isomers of comonomers from polyolefin elastomer solutions. By effectively recovering system energy, it reduces the amount of heating medium used, lowers process energy consumption, reduces production costs, and reduces greenhouse gas emissions. The equipment used has a high degree of integration, which helps to reduce equipment investment and operating costs and save equipment space.

[0026] The method for separating the polyolefin elastomer solution according to embodiments of the present invention can be as follows: Figure 1 The separation is carried out using the separation device shown.

[0027] In some embodiments, the process of the polyolefin elastomer solution entering the primary flash evaporator V1 for first separation to obtain a first volatile component and a first concentrated phase includes: adjusting the pressure of the polyolefin elastomer solution to 6-10 MPa, for example, 6 MPa, 7 MPa, 8 MPa, 9 MPa, 10 MPa or any combination thereof; and then allowing the polyolefin elastomer solution to enter (be conveyed to) the primary flash evaporator V1 for first separation (phase separation), producing a non-polymer gas phase composed of volatiles, i.e., the first volatile component, and a polyolefin elastomer solution (polymer solution), i.e., the first concentrated phase.

[0028] The pressure inside the first-stage flash evaporator V1 can be 2.0 to 4.0 MPa, for example, 2.0, 3.0, 4.0 MPa or any combination thereof, which helps to improve the effect of the first separation and effectively separate the non-polymer gas phase and polymer solution in the polyolefin elastomer solution.

[0029] Furthermore, the process of the polyolefin elastomer solution entering the first-stage flash evaporator V1 for first separation to obtain the first volatile component and the first concentrated phase includes: adjusting the pressure of the polyolefin elastomer solution to 6-10 MPa, for example, 6 MPa, 7 MPa, 8 MPa, 9 MPa, 10 MPa or any combination thereof; then preheating it to 250-300°C via the solution preheater E1, for example, 250°C, 260°C, 270°C, 280°C, 290°C, 300°C or any combination thereof; then reducing the pressure via the first pressure reducing valve; and then entering the first-stage flash evaporator V1 for first separation (phase separation), producing a non-polymer gas phase composed of volatiles, i.e., the first volatile component, and a concentrated phase containing the polyolefin elastomer solution (polymer solution), i.e., the first concentrated phase, which is beneficial to further improve the separation effect of the non-polymer gas phase and polymer solution in the polyolefin elastomer solution.

[0030] In the process of adjusting the pressure of the polyolefin elastomer solution to 6-10 MPa, a pump can generally be used to pressurize the polyolefin elastomer solution to reach the specified pressure.

[0031] In some embodiments, the process of the first concentrated phase entering the secondary flash evaporator V2 for second separation to obtain a second volatile component and a second concentrated phase containing polyolefin elastomer includes: the first concentrated phase is depressurized by a second pressure reducing valve and then enters (is transported to) the secondary flash evaporator V2 for second separation (phase separation) to obtain a non-polymer gas phase composed of volatiles, i.e., the second volatile component, and a polymer solution concentrated phase, i.e., the second concentrated phase containing polyolefin elastomer, thereby effectively separating the polyolefin elastomer (POE) from the polyolefin elastomer solution.

[0032] The pressure inside the secondary flash evaporator V2 can be 0.2 to 0.5 MPa, for example, 0.2 MPa, 0.3 MPa, 0.4 MPa, 0.5 MPa or any combination thereof, which helps to improve the effect of the second separation and effectively separate the second volatile component and the second concentrated phase containing polyolefin elastomer.

[0033] Understandably, the first volatile component can be discharged from the top of the first-stage flash evaporator V1, the first concentrated phase can be discharged from the bottom of the first-stage flash evaporator V1, and the polyolefin elastomer solution can enter from the upper inlet of the first-stage flash evaporator V1; similarly, the second volatile component can be discharged from the top of the second-stage flash evaporator V2, the second concentrated phase can be discharged from the bottom of the second-stage flash evaporator V2, and the first concentrated phase can enter from the upper inlet of the second-stage flash evaporator V2.

[0034] The first volatile component contains a high amount of heat. Through heat exchange in the first heat exchanger, some of the heat in the first volatile component is transferred to the cooling medium (e.g., condensate), resulting in a cooled first volatile component and steam formed by the cooling medium. This steam, containing a high amount of heat, transfers heat to the ethylene recovery tower T2 as it flows through the reboiler, providing a heat source for the ethylene recovery tower T2. By employing thermal integration technology, the energy within the system is fully utilized, saving the heating medium of the ethylene recovery tower T2, achieving excellent energy-saving effects, reducing process energy consumption, lowering production costs, and reducing greenhouse gas emissions.

[0035] In some embodiments, the steam is saturated steam with a pressure of 1.2–1.5 MPa, and the saturated steam is discharged from the cold side outlet of the first heat exchanger E2; the temperature of the cooled first volatile component is 210–240°C, that is, the first volatile component is cooled to 210–240°C after heat exchange in the first heat exchanger E2. Exemplarily, the pressure of the saturated steam can be a range of 1.2 MPa, 1.3 MPa, 1.4 MPa, 1.5 MPa, or any combination thereof; the temperature of the cooled first volatile component can be a range of 210°C, 220°C, 230°C, 240°C, or any combination thereof.

[0036] The first volatile component cooled above is conveyed to the pre-separation tower T1.

[0037] The second volatile component is cooled into a liquid by the first condenser E3. The liquid is then transported to the second heat exchanger E4 by the first pressurization pump. After exchanging heat with the cooled third light component flowing through the second heat exchanger E4, a preheated second volatile component is obtained. The preheated second volatile component enters the pre-separation tower T1 and mixes with the cooled first volatile component entering the pre-separation tower T1. A third separation occurs, yielding a first light component and a first heavy component.

[0038] The pressure inside the pre-separation tower T1 can be 1.8 to 2.4 MPa, for example, 1.8 MPa, 1.9 MPa, 2.0 MPa, 2.1 MPa, 2.2 MPa, 2.3 MPa, 2.4 MPa or any combination thereof, which helps to improve the effect of the third separation and effectively separate the first light component and the first heavy component.

[0039] The logarithmic mean temperature difference between the cold-side feed and the hot-side feed of the second heat exchanger E4 can be 10 to 30°C, for example, 10°C, 15°C, 20°C, 25°C, 30°C, or any combination thereof.

[0040] In some embodiments, an additional stream of butene enters the first condenser reflux tank of the pre-separation tower T1, which allows a portion of the butene to enter the pre-separation tower T1, thus the aforementioned first light component generally includes solvent, ethylene, and butene.

[0041] Using butene as the third component can increase the dew point temperature of the first light component discharged from the pre-separation tower T1, thereby allowing cooling water to be used as the cooling medium during the cooling of the first light component, saving operating costs.

[0042] The process of the first light component entering the ethylene recovery tower T2 (for example, after the first light component is output from the first condenser reflux tank, it enters the middle of the ethylene recovery tower T2 from the middle inlet) and undergoing the fourth separation to obtain the second light component and the second heavy component containing ethylene includes: after the first light component is cooled by the second condenser, it enters the first condenser reflux tank and mixes with the butene entering the first condenser reflux tank, and then enters the ethylene recovery tower T2 to undergo the fourth separation to obtain the second light component and the second heavy component containing ethylene, thereby effectively separating the ethylene from the polyolefin elastomer solution.

[0043] The steam generated by the first heat exchanger flows through the reboiler of the ethylene recovery tower T2, transferring heat to the ethylene recovery tower T2 to provide a heat source. This enables the recovery and reuse of heat from the first volatile component, reduces the heating medium in the ethylene recovery tower T2, saves energy, and lowers production costs.

[0044] The pressure inside the ethylene recovery tower T2 can be 1.6 to 2.2 MPa, for example, 1.6 MPa, 1.7 MPa, 1.8 MPa, 1.9 MPa, 2.0 MPa, 2.2 MPa or any combination thereof.

[0045] In some embodiments, the second light component containing ethylene is cooled by a third condenser and then enters a second condenser reflux tank to complete the separation of ethylene from the polyolefin elastomer solution.

[0046] Understandably, the second light component also includes a small amount of butene; the second heavy component includes ethylene, butene, and solvent.

[0047] In some embodiments, the second heavy component is sent back to the first condenser reflux tank of the pre-separation tower T1 to facilitate its return to the pre-separation tower T1 for repeated third separation.

[0048] Furthermore, in the first condenser reflux tank, the molar ratio of butene to ethylene in the first light component is (5-15):1, which helps to increase the dew point temperature of the first light component discharged from the pre-separation tower T1, ensuring that the pre-separation tower T1 can use cooling water as the cooling medium, thus saving operating costs.

[0049] Understandably, in order to ensure that the butene content in the first condenser reflux tank remains constant, the amount of butene (fresh butene) added to the first condenser reflux tank of the pre-separation tower T1 should be equal to the amount of butene in the second light component extracted from the ethylene recovery tower T2.

[0050] The first heavy component includes solvent, oligomeric oil, comonomer, and isomer of comonomer. The first heavy component enters solvent recovery tower T3 (for example, it can enter the middle of solvent recovery tower T3 through the middle inlet) and undergoes fifth separation to obtain a third light component containing solvent and a third heavy component.

[0051] Under the same pressure, the boiling point of the solvent is lower than that of the comonomer and its isomers. For example, the boiling point of the solvent is lower than that of 1-octene and its isomers, which is beneficial to separate the solvent from the solvent recovery tower in advance, so as to effectively separate the solvent from the comonomer and its isomers.

[0052] The pressure inside the solvent recovery tower can be 500 to 800 kPa, for example, 500 kPa, 600 kPa, 700 kPa, 800 kPa or any combination thereof.

[0053] In some embodiments, the aforementioned third light component containing solvent is cooled to obtain a cooled third light component, which is used as a hot component flowing through the second heat exchanger. Part of its heat is then supplied to the second volatile component, which is cooled to a liquid state, thereby obtaining a preheated second volatile component. By employing thermal integration technology, the energy within the system is fully utilized, achieving excellent energy-saving results.

[0054] Furthermore, the process of obtaining a cooled third light component after cooling the aforementioned solvent-containing third light component includes: the solvent-containing third light component recovers first heat through the first reboiler of the solvent recovery tower T3, and the recovered first heat is used for the fifth separation, while simultaneously obtaining the cooled third light component. In this process, the solvent-containing third light component is used to provide a heat source for the first reboiler of the solvent recovery tower T3. By employing thermal integration technology, the energy within the system is fully utilized, achieving good energy-saving effects.

[0055] Furthermore, the process of recovering the first heat from the third light component containing solvent in the first reboiler of the solvent recovery tower T3, and using the recovered first heat for the fifth separation, while obtaining a cooled third light component, includes: the third light component containing solvent is pressurized and heated by the first heat pump (heat pump unit) and then the first heat is recovered in the first reboiler of the solvent recovery tower T3, and the recovered first heat is used for the fifth separation, while obtaining a cooled third light component; wherein, the cooled third light component is successively depressurized by the third pressure reducing valve and cooled by the fourth condenser, and then enters the top reflux tank of the solvent recovery tower T3, thereby completing the solvent separation. In the above process, by using a heat pump recovery system, the heat of the third light component is recovered to meet its own heat demand (solvent recovery tower T3), thereby achieving the recovery of low-grade waste heat at the top of solvent recovery tower T3 (recovery of heat from the third light component) with less compression work. This reduces the heat load of the second reboiler (bottom reboiler) of solvent recovery tower T3, saves the amount of bottom steam used, and also saves the amount of cooling water used at the top of solvent recovery tower T3 during the cooling of the third light component, thus saving operating costs and reducing energy consumption.

[0056] The third component includes solvent, oligomeric oil, comonomer, and isomerized comonomer. It is generally collected from the bottom of the solvent recovery tower T3 and then transported to the oil separation tower T4.

[0057] The third heavy component enters the oil separation tower T4 for the sixth separation, yielding the fourth light component, the intermediate component, and the fourth heavy component containing oligomer oils, thus achieving the separation of oligomer oils.

[0058] The pressure inside the oil separation tower T4 can be 500 to 800 kPa, for example, 500 kPa, 600 kPa, 700 kPa, 800 kPa or any combination thereof.

[0059] In some embodiments, such as Figure 1As shown, the aforementioned oil separation tower T4 (partitioned wall distillation tower) has a partition in the middle, dividing the internal space of the oil separation tower T4 into two regions along its longitudinal direction. The middle parts of the two regions are not connected, but the tops and bottoms of the two regions are connected. The third heavy component enters the oil separation tower T4 from the middle inlet on one side of the partition. A sixth separation occurs in the region near this middle inlet, yielding a fourth light component, an intermediate component, and a fourth heavy component containing oligomerized oils. The fourth light component includes solvent, comonomer, and isomers of the comonomer, and is generally collected from the top of the oil separation tower T4. The intermediate component includes comonomer and isomers of the comonomer, which can diffuse to another region away from this middle inlet, i.e., the other side of the partition, and then be discharged from the middle outlet of the other region. The fourth heavy component containing oligomerized oils also includes some comonomers, and is generally collected from the bottom of the oil separation tower T4, thus achieving the separation of oligomerized oils. The above-mentioned oil separation tower T4 (partition wall distillation tower) is used to separate the components in the third heavy component (multi-component mixture), realize the integration of equipment and energy, improve energy utilization, reduce equipment investment and operating costs, and save space.

[0060] In some embodiments, after the fourth light component is collected from the top of the oil separation tower T4, it is cooled by the fifth condenser and enters the third condenser reflux tank, and then is transported to the solvent recovery tower T3 to repeat the fifth separation.

[0061] Furthermore, after the fourth light component is collected from the top of the oil separation tower T4, it is cooled by the fifth condenser and enters the reflux tank of the third condenser. Then, it is transported to the solvent recovery tower T3 by the third pressurization pump to repeat the fifth separation.

[0062] The intermediate component can enter the primary comonomer recovery tower T5 from the top inlet and undergo the seventh separation to obtain the fifth light component and the fifth heavy component containing the isomer of the comonomer. The fifth light component includes the comonomer and the isomer of the comonomer. The fifth light component is generally collected from the top of the primary comonomer recovery tower T5. The fifth heavy component containing the isomer of the comonomer is generally collected from the bottom of the primary comonomer recovery tower T5, thereby realizing the separation of the isomer of the comonomer.

[0063] The pressure inside the primary copolymer recovery tower T5 can be 50 to 150 kPa, for example, 50 kPa, 60 kPa, 70 kPa, 80 kPa, 90 kPa, 100 kPa, 110 kPa, 120 kPa, 130 kPa, 140 kPa, 150 kPa or any combination thereof.

[0064] In some embodiments, after the fifth light component is pressurized and heated by the second heat pump (heat pump unit), it enters the secondary comonomer recovery tower T6 to undergo the eighth separation, obtaining a sixth light component and a sixth heavy component containing comonomers; wherein, the sixth heavy component includes comonomers and isomers of comonomers, and is generally collected from the bottom of the secondary comonomer recovery tower T6, depressurized by the fourth pressure valve, and returned to the primary comonomer recovery tower T5 to repeat the seventh separation.

[0065] The pressure inside the secondary copolymer recovery tower T6 can be 200 to 400 kPa, for example, 200 kPa, 300 kPa, 400 kPa or any combination thereof.

[0066] In some embodiments, the sixth light component containing comonomers flows through the reboiler of the primary comonomer recovery tower T5 to recover the second heat. The recovered second heat is used for the seventh separation, simultaneously obtaining a cooled sixth light component. The cooled sixth light component containing comonomers is then cooled again by the sixth condenser to complete the separation of comonomers. The aforementioned use of the recovered heat from the sixth light component containing comonomers to provide a heat source for the primary comonomer recovery tower T5 employs thermal integration technology, fully utilizing the energy within the system and achieving good energy-saving effects. Simultaneously, it utilizes less compression work to achieve the recovery of low-grade waste heat (heat recovery from the sixth light component) at the top of the secondary comonomer recovery tower T6, reducing the heat load of the primary comonomer recovery tower T5, saving the amount of cooling water at the top of the secondary comonomer recovery tower T6 and the steam in the bottom of the primary comonomer recovery tower T5, thus saving operating costs and reducing energy consumption.

[0067] The pressure difference between the primary copolymer recovery tower T5 and the secondary copolymer recovery tower T6 can be 100-300 kPa, for example, 100 kPa, 150 kPa, 200 kPa, 250 kPa, 300 kPa or any combination thereof. Since the boiling points of the copolymer and its isomers are similar, the separation of the two is difficult and costly. By adopting differential pressure thermal coupling distillation process, the amount of cooling water at the top of the secondary copolymer recovery tower T6 and the steam at the bottom of the primary copolymer recovery tower T5 is saved, thus reducing operating costs.

[0068] This invention also provides a separation device for polyolefin elastomer solutions, such as... Figure 1 As shown, it includes:

[0069] The first-stage flash evaporator V1 is provided with a material inlet, a first volatile component outlet, and a first concentrated phase outlet; wherein, the distance between the material inlet of the first-stage flash evaporator V1 and the top of the first-stage flash evaporator V1 can be from one-quarter to one-half of the height of the first-stage flash evaporator V1, the first volatile component outlet of the first-stage flash evaporator V1 can be located at the top of the first-stage flash evaporator V1, and the first concentrated phase outlet of the first-stage flash evaporator V1 can be located at the bottom of the first-stage flash evaporator V1;

[0070] The first heat exchanger E2 is provided with a first cold side inlet, a first cold side outlet, a first hot side outlet, and a first hot side inlet connected to the first volatile component outlet of the first stage flash evaporator V1;

[0071] The secondary flash evaporator V2 is provided with a second volatile component outlet, a second concentrated phase outlet, and a first concentrated phase inlet connected to the first concentrated phase outlet of the primary flash evaporator V1; wherein, the distance between the first concentrated phase inlet of the secondary flash evaporator V2 and the top of the secondary flash evaporator V2 can be from one-quarter to one-half of the height of the secondary flash evaporator V2, the second volatile component outlet of the secondary flash evaporator V2 can be located at the top of the secondary flash evaporator V2, and the second concentrated phase outlet of the secondary flash evaporator V2 can be located at the bottom of the secondary flash evaporator V2;

[0072] The pre-separation tower T1 is provided with a first light component outlet, a first heavy component outlet, a first top reflux inlet, a first bottom reflux inlet, and a volatile component inlet. The volatile component inlet is connected to the first cold side outlet of the first heat exchanger E2, and the volatile component inlet is connected to the second volatile component outlet of the secondary flash evaporator V2. The volatile component inlet of the pre-separation tower T1 can be located in the middle of the pre-separation tower T1, the first light component outlet of the pre-separation tower T1 can be located at the top of the pre-separation tower T1, and the first heavy component outlet of the pre-separation tower T1 can be located at the bottom of the pre-separation tower T1.

[0073] Ethylene recovery tower T2 is provided with a second light component outlet, a second top reflux inlet, a second bottom reflux inlet, a second heavy component outlet connected to the first top inlet of pre-separation tower T1, and a first light component inlet connected to the first light component outlet of pre-separation tower T1; wherein, the first light component inlet of ethylene recovery tower T2 may be located in the middle of ethylene recovery tower T2, the second light component outlet of ethylene recovery tower T2 may be located at the top of ethylene recovery tower T2, and the second heavy component outlet of ethylene recovery tower T2 may be located at the bottom of ethylene recovery tower T2;

[0074] Solvent recovery tower T3 is provided with a third light component outlet, a third heavy component outlet, a third top reflux inlet, a third bottom reflux inlet, a fourth light component inlet, a reboiler connected to the third light component outlet, and a first heavy component inlet connected to the first heavy component outlet of pre-separation tower T1; wherein, the first heavy component inlet of solvent recovery tower T3 may be located in the middle of solvent recovery tower T3, the third light component outlet of solvent recovery tower T3 may be located at the top of solvent recovery tower T3, the third heavy component outlet of solvent recovery tower T3 may be located at the bottom of solvent recovery tower T3, and the fourth light component inlet of solvent recovery tower T3 may be located at the bottom of solvent recovery tower T3;

[0075] The oil separation tower T4 is provided with an intermediate component outlet, a fourth heavy component outlet, a fourth top reflux inlet, a fourth bottom reflux inlet, a third heavy component inlet connected to the third heavy component outlet of the solvent recovery tower T3, and a fourth light component outlet connected to the fourth light component inlet of the solvent recovery tower T3. The fourth light component outlet of the oil separation tower T4 can be located at the top of the oil separation tower T4, the third heavy component inlet of the oil separation tower T4 can be located in the middle of the oil separation tower T4, the intermediate component outlet of the oil separation tower T4 can be located in the middle of the oil separation tower T4 and on the side far from the third heavy component inlet, and the fourth heavy component outlet of the oil separation tower T4 can be located at the bottom of the oil separation tower T4.

[0076] The primary copolymer monomer recovery tower T5 is equipped with a fifth heavy component outlet, a fifth light component outlet, a fifth bottom reflux inlet, a sixth heavy component inlet, and an intermediate component inlet connected to the intermediate component outlet of the oil separation tower T4. The intermediate component inlet of the primary copolymer monomer recovery tower T5 can be located at the top of the primary copolymer monomer recovery tower T5, the fifth light component outlet of the primary copolymer monomer recovery tower T5 can be located at the top of the primary copolymer monomer recovery tower T5, the fifth heavy component outlet of the primary copolymer monomer recovery tower T5 can be located at the bottom of the primary copolymer monomer recovery tower T5, and the sixth heavy component inlet of the primary copolymer monomer recovery tower T5 can be located at the top of the primary copolymer monomer recovery tower T5.

[0077] The secondary copolymer monomer recovery tower T6 is equipped with a sixth top reflux inlet, a sixth light component outlet connected to the reboiler of the primary copolymer monomer recovery tower T5, a fifth light component inlet connected to the fifth light component outlet of the primary copolymer monomer recovery tower T5, and a sixth heavy component outlet connected to the sixth heavy component inlet of the primary copolymer monomer recovery tower T5. The sixth light component outlet of the secondary copolymer monomer recovery tower T6 can be located at the top of the secondary copolymer monomer recovery tower T6, the fifth light component inlet and outlet of the secondary copolymer monomer recovery tower T6 can be located at the bottom of the secondary copolymer monomer recovery tower T6, and the sixth heavy component outlet of the secondary copolymer monomer recovery tower T6 can be located at the bottom of the secondary copolymer monomer recovery tower T6.

[0078] In some embodiments, a partition is provided in the middle of the oil separation tower T4. Along the longitudinal direction of the oil separation tower T4, the partition divides the internal space of the oil separation tower T4 into two regions. The middle parts of the two regions are not connected, the tops of the two regions are connected, and the bottoms of the two regions are connected. The third component inlet and the intermediate component outlet of the oil separation tower T4 are respectively located on the side walls corresponding to the middle parts of the two regions.

[0079] In some embodiments, the separation device further includes a solution preheater E1, which has a solution inlet and a material outlet connected to the material inlet of the first-stage flash evaporator V1; wherein a first pressure reducing valve is provided between the material outlet of the solution preheater E1 and the material inlet of the first-stage flash evaporator V1.

[0080] In some embodiments, the separation device further includes a second pressure reducing valve located between the first concentrated phase outlet of the primary flash evaporator V1 and the first concentrated phase inlet of the secondary flash evaporator V2.

[0081] In some embodiments, the separation device further includes a second heat exchanger E4, which has a second cold-side inlet connected to the second volatile component outlet of the secondary flash evaporator V2, a second cold-side outlet connected to the volatile component inlet of the pre-separation tower T1, a second hot-side inlet connected to the reboiler of the solvent separation tower T3, and a second hot-side outlet.

[0082] In some embodiments, the separation device further includes a first condenser E3 and a first pressurizing pump, which are sequentially located between the second volatile component outlet of the secondary flash evaporator V2 and the second cold-side inlet of the second heat exchanger E4 along the direction of the material flow.

[0083] In some embodiments, the separation device further includes a third pressure reducing valve and a fourth condenser, which are sequentially disposed between the reboiler of the solvent separation tower T3 and the second hot-side inlet of the second heat exchanger E4.

[0084] In some embodiments, the separation device further includes a second condenser and a first condenser reflux tank. Along the direction of the material flow, the second condenser and the first condenser reflux tank are sequentially disposed between the first light component outlet of the pre-separation tower T1 and the first light component inlet of the ethylene recovery tower T2. The first condenser reflux tank is further provided with a first reflux outlet communicating with the first top reflux inlet of the pre-separation tower T1, a butene inlet, and an inlet communicating with the second heavy component outlet of the ethylene recovery tower T2.

[0085] In some embodiments, the separation device further includes a second pressurizing pump located between the inlet of the second heavy component of the ethylene recovery tower T2 and the inlet of the first condenser reflux tank.

[0086] In some embodiments, the separation device further includes a third condenser and a second condenser reflux tank, which are sequentially disposed between the second light component outlet of the ethylene recovery tower T2 and the second top reflux inlet of the ethylene recovery tower T2 along the direction of the material flow; wherein the second condenser reflux tank is also provided with an ethylene outlet.

[0087] In some embodiments, the separation device further includes a first heat pump located between the third light component outlet of the solvent recovery tower T3 and the first reboiler of the solvent recovery tower T3.

[0088] In some embodiments, the first reboiler of the solvent recovery tower is located in the middle of the solvent recovery tower, and the solvent recovery tower includes a second reboiler (bottom reboiler) located at the bottom.

[0089] In some embodiments, the separation device further includes a fifth condenser, a third condenser reflux tank, and a third pressurizing pump. Along the direction of the material flow, the fifth condenser, the third condenser reflux tank, and the third pressurizing pump are sequentially arranged between the fourth light component outlet of the grease separation tower T4 and the fourth light component inlet of the solvent recovery tower T3. The third condenser reflux tank is also provided with an outlet that communicates with the fourth top reflux inlet of the grease separation tower T4.

[0090] In some embodiments, the separation device further includes a second heat pump located between the fifth light component outlet of the primary comonomer recovery tower T5 and the fifth light component inlet of the secondary comonomer recovery tower T6.

[0091] In some embodiments, the separation device further includes a fourth pressure reducing valve, located between the outlet of the sixth heavy component of the secondary copolymer recovery tower T6 and the inlet of the sixth heavy component of the primary copolymer recovery tower T5.

[0092] Specifically, the cooling medium of the first condenser may include water, the cooling medium of the second condenser may include water, the cooling medium of the third condenser may include liquid ammonia, the cooling medium of the fourth condenser may include water, and the cooling medium of the fifth condenser may include water.

[0093] The present invention will now be described in more detail through specific embodiments and comparative examples.

[0094] Example 1

[0095] Adopting such Figure 1 The separation device shown separates the components in the polyolefin elastomer solution. The separation process is as follows:

[0096] The pressure of the polyolefin elastomer solution is adjusted to 6-10 MPa; then it is preheated to 250-300°C by the solution preheater E1, then depressurized by the first pressure reducing valve, and then enters the first flash evaporator V1 to undergo the first separation, obtaining the first volatile component and the first concentrated phase. The pressure in the first flash evaporator V1 is 2.0-4.0 MPa.

[0097] The first volatile component exchanges heat with the condensate flowing through the first heat exchanger E2 to obtain a cooled first volatile component and saturated steam. The saturated steam transfers heat to the ethylene recovery tower T2 when it flows through the reboiler, providing a heat source for the ethylene recovery tower T2. The pressure of the saturated steam is 1.2 to 1.5 MPa, and the temperature of the cooled first volatile component is 210 to 240°C. The cooled first volatile component is then transported to the pre-separation tower T1.

[0098] After the first concentrated phase is depressurized by the second pressure reducing valve, it is sent to the second flash evaporator V2 for second separation to obtain the second volatile component and the second concentrated phase containing polyolefin elastomer (POE). The pressure inside the second flash evaporator V2 can be 0.2 to 0.5 MPa.

[0099] The second volatile component is cooled into a liquid by the first condenser E3. This liquid is then transported to the second heat exchanger E4 by the first pressurized pump. After exchanging heat with the cooled third light component flowing through the second heat exchanger E4, a preheated second volatile component is obtained. The preheated second volatile component enters the pre-separation tower T1, where it mixes with the cooled first volatile component entering the pre-separation tower T1 and undergoes a third separation to obtain a first light component and a first heavy component. Simultaneously, a stream of butene B enters the first condenser reflux tank of the pre-separation tower T1. The pressure inside the pre-separation tower T1 can be 1.8–2.4 MPa. The logarithmic mean temperature difference between the cold side feed and the hot side feed of the second heat exchanger E4 is 10–30 °C. In the first condenser reflux tank, the molar ratio of butene to ethylene is (5–15):1.

[0100] After the first light component exits from the first condenser reflux tank, it enters the middle section of the ethylene recovery tower T2 through the first light component inlet to undergo the fourth separation, yielding a second light component and a second heavy component containing ethylene. The second light component containing ethylene is cooled by the third condenser and then enters the second condenser reflux tank, completing the separation of ethylene A from the polyolefin elastomer solution. The second heavy component is pressurized by the second pressurizing pump and sent back to the first condenser reflux tank of the pre-separation tower T1 for repeated third separation. The pressure inside the ethylene recovery tower T2 is 1.6–2.2 MPa.

[0101] The first heavy component enters the solvent recovery tower T3 for the fifth separation, yielding a third light component containing solvent and a third heavy component; the pressure inside the solvent recovery tower is 500–800 kPa;

[0102] After the third light component containing solvent is collected from the top of the solvent recovery tower T3, it is pressurized and heated by the first heat pump (heat pump unit) and then the first heat is recovered by the first reboiler of the solvent recovery tower T3. The recovered heat is used for the fifth separation, and at the same time, the cooled third light component is obtained. The cooled third light component is then depressurized by the third pressure reducing valve and cooled by the fourth condenser before entering the top reflux tank of the solvent recovery tower T3, thus completing the separation of solvent C.

[0103] The third heavy component enters the oil separation tower T4 for the sixth separation, yielding a fourth light component, an intermediate component, and a fourth heavy component containing oligomer oils. The oil separation tower T4 is a partitioned-wall distillation tower. The fourth light component is collected from the top of the oil separation tower T4, cooled by the fifth condenser, and then enters the third condenser reflux tank before being transported to the solvent recovery tower T3 for a repeat of the fifth separation. The fourth heavy component containing oligomer oils is collected from the bottom of the oil separation tower T4, thus achieving the separation of oligomer oil D. The intermediate component is discharged from the intermediate component outlet in the middle of the oil separation tower T4 and then enters the primary comonomer recovery tower T5. The pressure inside the oil separation tower T4 is 300–500 kPa.

[0104] The intermediate component enters the primary comonomer recovery tower T5 for the seventh separation, yielding the fifth light component and the fifth heavy component containing the comonomer isomer F; the pressure inside the primary comonomer recovery tower T5 is 50–150 kPa;

[0105] The fifth light component, after being pressurized and heated by the second heat pump (heat pump unit), enters the secondary comonomer recovery tower T6 for the eighth separation, yielding a sixth light component and a sixth heavy component containing comonomers. The sixth heavy component is collected from the bottom of the secondary comonomer recovery tower T6, depressurized by the fourth pressure valve, and returned to the primary comonomer recovery tower T5 for the seventh separation. The sixth light component containing comonomers flows through the reboiler of the primary comonomer recovery tower T5 to recover the second heat, which is used for the seventh separation, simultaneously yielding a cooled sixth light component. The cooled sixth light component containing comonomers is then cooled by the sixth condenser, completing the separation of comonomer E. The pressure inside the secondary comonomer recovery tower T6 is 200–400 kPa; the pressure difference between the primary comonomer recovery tower T5 and the secondary comonomer recovery tower T6 can be 100–300 kPa.

[0106] Comparative Example 1

[0107] Adopting such Figure 2The separation device shown separates the components in the polyolefin elastomer solution. The separation process is basically the same as in Example 1, except that:

[0108] 1) The third light component containing solvent is collected from the top of the solvent recovery tower T3, cooled by the fourth condenser, and then enters the top reflux tank of the solvent recovery tower T3, thus completing the separation of solvent C.

[0109] 2) The third heavy component enters the oil separation tower T4 for the sixth separation, yielding the fourth light component and the fourth heavy component. The oil separation tower T4 is a conventional tower without a baffle plate in the middle. The fourth light component is collected from the top of the oil separation tower T4, cooled by the fifth condenser, and then enters the third condenser reflux tank before being transported to the solvent recovery tower T3 for a repeat of the fifth separation. The fourth heavy component is collected from the bottom of the oil separation tower T4 and transported to the primary comonomer recovery tower T5.

[0110] 3) The fourth heavy component enters the primary comonomer recovery tower T5 and undergoes the seventh separation to obtain the fifth light component and the fifth heavy component containing oligomer oil D;

[0111] 4) After being cooled by the condenser, the fifth light component enters the condenser reflux tank and is then transported to the secondary comonomer recovery tower T6 for the eighth separation, resulting in a sixth light component containing comonomer E and a sixth heavy component containing isomer F of copolymer monomer. The sixth light component is collected from the top of the secondary comonomer recovery tower T6, cooled by the condenser, and then enters the condenser reflux tank. The sixth heavy component is collected from the bottom of the secondary comonomer recovery tower T6.

[0112] Test case

[0113] Aspen Plus software was used for process simulation, and material and energy balance calculations were performed for the process flows of Example 1 and Comparative Example 1. The operating conditions and material balance table for Example 1 are shown in Table 1; the operating conditions and material balance table for Comparative Example 1 are shown in Table 2.

[0114] Table 1. Operating conditions and material balance table for Example 1

[0115]

[0116]

[0117]

[0118] Table 2. Operating conditions and material balance table for Comparative Example 1

[0119]

[0120]

[0121] Data Analysis:

[0122] As can be seen from Example 1 and Comparative Example 1, the separation method of polyolefin elastomer solution of the present invention can save the load of units including the reboiler of the solvent recovery tower, the condenser at the top of the solvent recovery tower, the reboiler of the comonomer recovery tower, and the condenser at the top of the comonomer recovery tower, reduce the amount of steam and cooling water used, and reduce operating costs; reduce the number of heat exchangers, reduce equipment investment and operating costs, and save space.

[0123] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention, and not to limit them; although the present invention has been described in detail with reference to the foregoing embodiments, those skilled in the art should understand that modifications can still be made to the technical solutions described in the foregoing embodiments, or equivalent substitutions can be made to some or all of the technical features; and these modifications or substitutions do not cause the essence of the corresponding technical solutions to deviate from the scope of the technical solutions of the embodiments of the present invention.

Claims

1. A method for separating a polyolefin elastomer solution, characterized in that, The separation method employs a separation device comprising a primary flash evaporator, a secondary flash evaporator, a pre-separation tower, an ethylene recovery tower, a solvent recovery tower, an oil separation tower, a primary comonomer recovery tower, and a secondary comonomer recovery tower; the polyolefin elastomer solution comprises polyolefin elastomer, ethylene, solvent, oligomeric oils, comonomers, and isomers of the comonomers; the separation method includes: The polyolefin elastomer solution enters the first-stage flash evaporator where a first separation occurs, yielding a first volatile component and a first concentrated phase; The first concentrated phase enters the secondary flash evaporator and undergoes a second separation to obtain a second volatile component and a second concentrated phase containing polyolefin elastomer; After the first volatile component exchanges heat with the cooling medium flowing through the first heat exchanger, a cooled first volatile component and steam formed by the cooling medium are obtained; the cooled first volatile component enters the pre-separation tower; the steam is used to provide a heat source for the ethylene recovery tower; After the second volatile component is cooled to a liquid state, it exchanges heat with the hot component flowing through the second heat exchanger to obtain a preheated second volatile component. The preheated second volatile component enters the pre-separation tower and mixes with the cooled first volatile component entering the pre-separation tower, and then undergoes a third separation to obtain a first light component and a first heavy component. The first light component enters the ethylene recovery tower for a fourth separation, yielding a second light component and a second heavy component containing ethylene; wherein the second heavy component is returned to the pre-separation tower to repeat the third separation. The first heavy component enters the solvent recovery tower and undergoes a fifth separation to obtain a third light component containing solvent and a third heavy component. The third light component containing solvent is cooled to obtain a cooled third light component. The hot component flowing through the second heat exchanger includes the cooled third light component. The third heavy component enters the oil separation tower for a sixth separation, yielding a fourth light component, an intermediate component, and a fourth heavy component containing oligomer oils; the fourth light component is returned to the solvent recovery tower for a fifth separation. The intermediate component enters the primary comonomer recovery tower where a seventh separation occurs, yielding a fifth light component and a fifth heavy component containing isomers of the comonomer; The fifth light component enters the secondary comonomer recovery tower for the eighth separation, yielding a sixth light component and a sixth heavy component containing comonomers; the sixth heavy component is returned to the primary comonomer recovery tower for a repeated seventh separation.

2. The separation method according to claim 1, characterized in that, The third light component containing solvent recovers the first heat in the first reboiler of the solvent recovery tower. The recovered first heat is used for the fifth separation, and a cooled third light component is obtained at the same time. And / or, the sixth light component flows through the reboiler of the primary comonomer recovery tower to recover the second heat, and the recovered second heat is used for the seventh separation, while obtaining the cooled sixth light component; And / or, the boiling point of the solvent is lower than that of the comonomer and the isomer of the comonomer.

3. The separation method according to claim 2, characterized in that, The process of recovering the first heat from the third light component containing solvent in the solvent recovery tower via the first reboiler, and using the recovered first heat for the fifth separation, while obtaining a cooled third light component, includes: the third light component containing solvent being pressurized and heated by a first heat pump, and then recovering the first heat from the first reboiler in the solvent recovery tower, with the recovered first heat used for the fifth separation, while obtaining a cooled third light component; wherein, the cooled third light component is sequentially depressurized by a third pressure reducing valve and cooled by a fourth condenser before entering the top reflux tank of the solvent recovery tower to complete the solvent separation; And / or, the sixth light component containing comonomer flows through the reboiler of the primary comonomer recovery tower to recover the second heat, and the recovered second heat is used for the seventh separation, while obtaining a cooled sixth light component containing comonomer; the cooled sixth light component containing comonomer is then cooled by the sixth condenser to complete the separation of the comonomer.

4. The separation method according to claim 1, characterized in that, The process of the polyolefin elastomer solution entering the first-stage flash evaporator for first separation to obtain the first volatile component and the first concentrated phase includes: adjusting the pressure of the polyolefin elastomer solution to 6-10 MPa, preheating it to 250-300°C by a solution preheater, then depressurizing it by a first pressure reducing valve, and then entering the first-stage flash evaporator for first separation to obtain the first volatile component and the first concentrated phase. And / or, the process of the first concentrated phase entering the secondary flash evaporator for second separation to obtain a second volatile component and a second concentrated phase containing polyolefin elastomer includes: the first concentrated phase being depressurized by a second pressure reducing valve and then entering the secondary flash evaporator for second separation to obtain a second volatile component and a second concentrated phase containing polyolefin elastomer; And / or, after the second volatile component is cooled to a liquid state, it exchanges heat with the hot component flowing through the second heat exchanger to obtain a preheated second volatile component. The preheated second volatile component enters the pre-separation tower and mixes with the cooled first volatile component entering the pre-separation tower, where a third separation occurs to obtain a first light component and a first heavy component. This includes: the second volatile component is cooled to a liquid state by a first condenser; the liquid is pumped to the second heat exchanger by a first pressurizing pump and exchanges heat with the cooled third light component flowing through the second heat exchanger to obtain a preheated second volatile component; the preheated second volatile component enters the pre-separation tower and mixes with the cooled first volatile component entering the pre-separation tower, where a third separation occurs to obtain a first light component and a first heavy component; wherein the logarithmic mean temperature difference between the cold-side feed and the hot-side feed of the second heat exchanger is 10–30°C. And / or, the process of the first light component entering the ethylene recovery tower for the fourth separation to obtain the second light component containing ethylene and the second heavy component includes: the first light component being cooled by the second condenser, entering the first condenser reflux tank and mixing with butene entering the first condenser reflux tank, and then entering the ethylene recovery tower for the fourth separation to obtain the second light component containing ethylene and the second heavy component; wherein, in the first condenser reflux tank, the molar ratio of butene to ethylene in the first light component is (5~15):1; And / or, the second light component containing ethylene is cooled by the third condenser and then enters the second condenser reflux tank to complete the separation of ethylene; And / or, the process of returning the fourth light component to the solvent recovery tower to repeat the fifth separation includes: the fourth light component being cooled by the fifth condenser, entering the third condenser reflux tank, and then being transported to the solvent recovery tower by the third pressurization pump to repeat the fifth separation; And / or, the process of the fifth light component entering the secondary comonomer recovery tower to undergo the eighth separation and obtain the sixth light component and the sixth heavy component containing comonomer includes: the fifth light component is pressurized and heated by the second heat pump, and then enters the secondary comonomer recovery tower to undergo the eighth separation and obtain the sixth light component and the sixth heavy component containing comonomer; And / or, the process of the sixth recombinant component returning to the primary comonomer recovery tower to repeat the seventh separation includes: the sixth recombinant component being depressurized by the fourth pressure reducing valve and then returning to the primary comonomer recovery tower to repeat the seventh separation.

5. The separation method according to claim 1, characterized in that, The pressure inside the primary flash evaporator is 2.0–4.0 MPa; And / or, the pressure inside the secondary flash evaporator is 0.2–0.5 MPa; And / or, the pressure of the saturated steam is 1.2–1.5 MPa; And / or, the pressure inside the pre-separation tower is 1.8–2.4 MPa; And / or, the pressure inside the ethylene recovery tower is 1.6–2.2 MPa; And / or, the pressure inside the solvent recovery tower is 500–800 kPa; And / or, the pressure inside the oil separation tower is 300–500 kPa; And / or, the pressure inside the primary copolymer recovery tower is 50–150 kPa; And / or, the pressure inside the secondary copolymer recovery tower is 200–400 kPa; And / or, the pressure difference between the primary copolymer recovery tower and the secondary copolymer recovery tower is 100-300 kPa.

6. A separation device for a polyolefin elastomer solution, characterized in that, include: The first-stage flash evaporator is equipped with a material inlet, a first volatile component outlet, and a first concentrated phase outlet; The first heat exchanger is provided with a first cold-side inlet, a first cold-side outlet, a first hot-side outlet, and a first hot-side inlet connected to the first volatile component outlet of the first-stage flash evaporator; The secondary flash evaporator is provided with a second volatile component outlet, a second concentrated phase outlet, and a first concentrated phase inlet connected to the first concentrated phase outlet of the primary flash evaporator; The pre-separation tower is provided with a first light component outlet, a first heavy component outlet, a first top reflux inlet, a first bottom reflux inlet, and a volatile component inlet. The volatile component inlet is connected to the first cold side outlet of the first heat exchanger and the volatile component inlet is connected to the second volatile component outlet of the secondary flash evaporator. The ethylene recovery tower is provided with a second light component outlet, a second top reflux inlet, a second bottom reflux inlet, a second heavy component outlet connected to the first top inlet of the pre-separation tower, and a first light component inlet connected to the first light component outlet of the pre-separation tower. The solvent recovery tower is provided with a third light component outlet, a third heavy component outlet, a third top reflux inlet, a third bottom reflux inlet, a fourth light component inlet, a reboiler connected to the third light component outlet, and a first heavy component inlet connected to the first heavy component outlet of the pre-separation tower. The oil separation tower is provided with an intermediate component outlet, a fourth heavy component outlet, a fourth top reflux inlet, a fourth bottom reflux inlet, a third heavy component inlet connected to the third heavy component outlet of the solvent recovery tower, and a fourth light component outlet connected to the fourth light component inlet of the solvent recovery tower. The primary copolymer monomer recovery tower is equipped with a fifth heavy component outlet, a fifth light component outlet, a fifth bottom reflux inlet, a sixth heavy component inlet, and an intermediate component inlet connected to the intermediate component outlet of the oil separation tower. The secondary copolymer monomer recovery tower is provided with a sixth top reflux inlet, a sixth light component outlet connected to the reboiler of the primary copolymer monomer recovery tower, a fifth light component inlet connected to the fifth light component outlet of the primary copolymer monomer recovery tower, and a sixth heavy component outlet connected to the sixth heavy component inlet of the primary copolymer monomer recovery tower.

7. The separation device according to claim 6, characterized in that, Also includes: The solution preheater is provided with a solution inlet and a material outlet connected to the material inlet of the first-stage flash evaporator; wherein a first pressure reducing valve is provided between the material outlet of the solution preheater and the material inlet of the first-stage flash evaporator; And / or, a second pressure reducing valve is located between the first concentrated phase outlet of the first-stage flash evaporator and the first concentrated phase inlet of the second-stage flash evaporator; And / or, the second heat exchanger is provided with a second cold-side inlet connected to the second volatile component outlet of the secondary flash evaporator, a second cold-side outlet connected to the volatile component inlet of the pre-separation tower, a second hot-side inlet connected to the reboiler of the solvent separation tower, and a second hot-side outlet. The first condenser and the first pressurizing pump are sequentially located between the second volatile component outlet of the secondary flash evaporator and the second cold side inlet of the second heat exchanger, along the direction of material flow. The third pressure reducing valve and the fourth condenser are sequentially located between the reboiler of the solvent separation tower and the second hot-side inlet of the second heat exchanger. And / or, the second condenser and the first condenser reflux tank, along the direction of the material flow, are sequentially arranged between the first light component outlet of the pre-separation tower and the first light component inlet of the ethylene recovery tower; wherein, the first condenser reflux tank is further provided with a first reflux outlet communicating with the first top reflux inlet of the pre-separation tower, a butene inlet, and an inlet communicating with the second heavy component outlet of the ethylene recovery tower; The second booster pump is located between the second heavy component of the ethylene recovery tower and the inlet of the first condenser reflux tank; And / or, a third condenser and a second condenser reflux tank, along the direction of the material flow, wherein the third condenser and the second condenser reflux tank are sequentially located between the second light component outlet of the ethylene recovery tower and the second top reflux inlet of the ethylene recovery tower; wherein, the second condenser reflux tank is also provided with an ethylene outlet; And / or, a first heat pump is located between the third light component outlet of the solvent recovery tower and the first reboiler of the solvent recovery tower; And / or, the first reboiler of the solvent recovery tower is located in the middle of the solvent recovery tower, and the solvent recovery tower includes a second reboiler located at the bottom; And / or, the fifth condenser, the third condenser reflux tank, and the third pressurizing pump are sequentially arranged between the fourth light component outlet of the grease separation tower and the fourth light component inlet of the solvent recovery tower along the direction of the material flow; wherein, the third condenser reflux tank is also provided with an outlet communicating with the fourth top reflux inlet of the grease separation tower; And / or, a second heat pump is located between the fifth light component outlet of the primary comonomer recovery tower and the fifth light component inlet of the secondary comonomer recovery tower; And / or, a fourth pressure reducing valve is located between the sixth heavy component outlet of the secondary copolymer recovery tower and the sixth heavy component inlet of the primary copolymer recovery tower.

8. The separation device according to claim 6 or 7, characterized in that, The distance between the material inlet of the first-stage flash evaporator and the top of the first-stage flash evaporator is from one-quarter to one-half of the height of the first-stage flash evaporator; And / or, the first volatile component outlet of the first-stage flash evaporator is located at the top of the first-stage flash evaporator; And / or, the first concentrated phase outlet of the first-stage flash evaporator is located at the bottom of the first-stage flash evaporator; And / or, the distance between the first concentrated phase inlet of the secondary flash evaporator and the top of the secondary flash evaporator is one-quarter to one-half of the height of the secondary flash evaporator; And / or, the second volatile component outlet of the secondary flash evaporator is located at the top of the secondary flash evaporator; And / or, the second concentrated phase outlet of the secondary flash evaporator is located at the bottom of the secondary flash evaporator; And / or, the volatile component inlet of the pre-separation tower is located in the middle of the pre-separation tower; And / or, the first light component outlet of the pre-separation tower is located at the top of the pre-separation tower; And / or, the first heavy component outlet of the pre-separation tower is located at the bottom of the pre-separation tower; And / or, the first light component inlet of the ethylene recovery tower is located in the middle of the ethylene recovery tower; And / or, the second light component outlet of the ethylene recovery tower is located at the top of the ethylene recovery tower; And / or, the second heavy component outlet of the ethylene recovery tower is located at the bottom of the ethylene recovery tower; And / or, the first heavy component inlet of the solvent recovery tower is located in the middle of the solvent recovery tower; And / or, the third light component outlet of the solvent recovery tower is located at the top of the solvent recovery tower; And / or, the third heavy component outlet of the solvent recovery tower is located at the bottom of the solvent recovery tower; And / or, the fourth light component inlet of the solvent recovery tower is located at the bottom of the solvent recovery tower; And / or, the fourth light component outlet of the oil separation tower is located at the top of the oil separation tower; And / or, the third heavy component inlet of the oil separation tower is located in the middle of the oil separation tower; And / or, the intermediate component outlet of the oil separation tower is located in the middle of the oil separation tower and on the side away from the inlet of the third heavy component; And / or, the fourth heavy component outlet of the oil separation tower is located at the bottom of the oil separation tower; And / or, the intermediate component inlet of the primary comonomer recovery tower is located at the top of the primary comonomer recovery tower; And / or, the fifth light component outlet of the primary comonomer recovery tower is located at the top of the primary comonomer recovery tower; And / or, the fifth heavy component outlet of the primary copolymer recovery tower is located at the bottom of the primary copolymer recovery tower; And / or, the sixth recombinant inlet of the primary copolymer recovery tower is located at the top of the primary copolymer recovery tower; And / or, the sixth light component outlet of the secondary comonomer recovery tower is located at the top of the secondary comonomer recovery tower; And / or, the fifth light component inlet and outlet of the secondary comonomer recovery tower are located at the bottom of the secondary comonomer recovery tower; And / or, the sixth recombinant component outlet of the secondary copolymer recovery tower is located at the bottom of the secondary copolymer recovery tower.

9. The separation device according to claim 6, characterized in that, The oil separation tower has a partition in the middle, which divides the internal space of the oil separation tower into two regions along the axial direction of the oil separation tower. The middle part of the two regions is not connected, the top of the two regions is connected, and the bottom of the two regions is connected. The third heavy component inlet and the intermediate component outlet of the oil separation tower are respectively located on the sidewalls corresponding to the middle part of the two regions.

10. The separation device according to claim 7, characterized in that, The cooling medium of the first condenser includes water; And / or, the cooling medium of the second condenser includes water; And / or, the cooling medium of the third condenser includes liquid ammonia; And / or, the cooling medium of the fourth condenser includes water; And / or, the cooling medium of the fifth condenser includes water.

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