A device and process for processing ethylene oligomers

Abstract

This invention provides a device for processing ethylene oligomers, comprising a settling filter, a pressure relief buffer tank, a three-in-one filter, and a filtrate buffer tank connected in sequence. The reaction liquid containing polymers enters the high aspect ratio settling filter from the flash evaporator system after the reaction section. Most of the filtered reaction liquid overflows from the top of the settling filter into the distillation system for distillation separation. A small portion of the settling and intercepted reaction liquid with high polymer concentration flows through the bottom of the settling filter into the pressure relief buffer tank. After being depressurized to atmospheric pressure, it enters the three-in-one filter for filtration. A small amount of depressurized ethylene is recovered and re-enters the reaction system. The polymers are filtered and intercepted in the three-in-one filter. The filtrates are combined and enter the distillation system. When a certain amount of polymers accumulates in the filter, another three-in-one filter is used. The accumulated polymers are dried and discharged. This process for online processing of polymers is simple, efficient, environmentally friendly, and safe.

Description

Technical Field

[0001] This invention belongs to the field of petrochemical technology, specifically relating to a device and process for processing ethylene oligomers. Background Technology

[0002] Linear α-olefins are important organic chemical raw materials and intermediates. They can be used as comonomers in the production of high-performance linear low-density polyethylene (LLDPE), high-density polyethylene (HDPE), and polyolefin elastomers (POE). They can also be used in the production of high-end lubricants, plasticizers, surfactants, and other fine chemicals. Currently, linear α-olefins are mainly produced through ethylene oligomerization and ethylene selective polymerization processes.

[0003] Currently, the production of polyethylene wax and polyethylene is unavoidable during the oligomerization and selective oligomerization of ethylene to prepare α-olefins. Patents such as CN102050841B, CN104338557B, and CN111774098A all mention that different catalytic systems will produce a certain amount of polymers as byproducts. During the flash evaporation and reuse of ethylene, these polymers will further precipitate as the reaction temperature decreases. In the slurry-based polyethylene process, some polyethylene wax is obtained by centrifugation and solvent evaporation to obtain a high-temperature soluble and highly fluid polyethylene wax fluid, which is then injected into water for precipitation and filtration. However, the polymers produced by oligomerization and selective oligomerization processes have extremely wide molecular weight distributions, ranging from hundreds to millions, and also contain 1%-30% high-boiling-point high-carbon olefins and alkanes, making them unsuitable for processing using the slurry-based dewaxing process.

[0004] In the oligomerization and selective oligomerization processes, the mixture after the reaction stage has a low polymer content, still has a certain pressure after flash evaporation, and some ethylene is dissolved in it. Using ordinary filtration methods results in a large volume of filtered liquid, and the pressure makes it impossible to use the automatic discharge device. The discharged solid has an excessively high moisture content, and the on-site environment and operation are difficult.

[0005] In view of the characteristics and problems of polymer by-products of ethylene oligomerization, it is necessary to find a new process method that can effectively and environmentally handle the polymer carryover in the material without affecting the entire process flow, achieve continuous output and obtain dried polymer, reduce the difficulty of operation and improve the on-site environment. Summary of the Invention

[0006] In view of this, the technical problem to be solved by the present invention is to provide a processing device and process for treating ethylene oligomers. The processing device for treating ethylene oligomers provided by the present invention can effectively realize the removal of polymers from the reaction liquid, reduce the difficulty of processing and operation, and improve the operational stability of the device.

[0007] The present invention provides a treatment device for ethylene oligomers, comprising a sedimentation filter, a pressure relief buffer tank, a three-in-one filter and a filtrate buffer tank connected in sequence.

[0008] Preferably, the height-to-diameter ratio of the sedimentation filter is 10:1 to 2:1.

[0009] Preferably, the settling filter comprises:

[0010] The flash-evaporated reaction liquid inlet with low polymer concentration is located in the middle of the side wall of the settling filter.

[0011] The clear liquid outlet is located at the top of the settling filter;

[0012] And a continuous discharge port for the mixed liquid located at the bottom of the settling filter.

[0013] Preferably, a filter element is provided in the upper part of the sedimentation filter, and the pore size of the filter element is 0.1 to 200 micrometers.

[0014] Preferably, the pressure relief buffer tank comprises:

[0015] The mixed liquid inlet is located in the middle of the side wall of the pressure relief buffer tank, and the mixed liquid inlet is connected to the mixed liquid continuous outlet at the bottom of the settling filter;

[0016] An ethylene pressure relief port is provided at the top of the pressure relief buffer tank;

[0017] And a polymer mixture outlet located at the bottom of the pressure relief buffer tank.

[0018] Preferably, the three-in-one filter includes:

[0019] The filter screen is disposed on the inner side of the three-in-one filter, and the pore size of the filter screen is 0.1 to 200 micrometers;

[0020] A stirring device is installed inside the three-in-one filter;

[0021] The liquid outlet is located at the bottom of the three-in-one filter;

[0022] A drying jacket device is installed on the outside of the three-in-one filter.

[0023] The present invention also provides a method for treating ethylene oligomers, comprising the following steps:

[0024] After flash evaporation, the reaction liquid with low polymer concentration under pressure is sequentially passed through a settling filter, a pressure relief buffer tank, and a three-in-one filter for solid-liquid separation. The resulting liquid enters the filtrate buffer tank, and the resulting solid is subjected to pressure filtration and drying to obtain ethylene oligomer.

[0025] Preferably, the mass concentration of polymer in the reaction solution with low polymer concentration after flash evaporation is 0.01% to 2%.

[0026] The ratio of the clear liquid at the top to the mixed liquid at the bottom after passing through the settling filter is 1:1 to 100:1.

[0027] The mass concentration of polymers in the mixture discharged from the bottom of the settling filter is 1% to 10%.

[0028] Preferably, the pressure inside the pressure relief buffer tank is 0 to 0.5 MPa.

[0029] Preferably, after filtration by the three-in-one filter, the polymer is trapped in the filter, and the liquid is continuously discharged into the filtrate buffer tank, and then pumped into the separation system for separation.

[0030] When the pressure difference across the three-in-one filter reaches 0.5 MPa, the feeding is stopped, and another three-in-one filter is switched to perform solid-liquid separation. The solids in the switched-off three-in-one filter are then subjected to nitrogen pressure filtration until the moisture content is 10-60%. A hot medium is then introduced into the jacket for drying until the moisture content is 0-10%. The material is then discharged and collected to obtain ethylene oligomers.

[0031] Compared with existing technologies, this invention provides a device for processing ethylene oligomers, comprising a settling filter, a pressure relief buffer tank, a three-in-one filter, and a filtrate buffer tank connected in sequence. The reaction liquid containing polymers enters the high aspect ratio settling filter from the flash tank system after the reaction section. Most of the filtered reaction liquid overflows from the top of the settling filter into the distillation system for distillation separation. A small amount of high-concentration polymer-rich reaction liquid, after settling and interception filtration, flows through the bottom of the settling filter into the pressure relief buffer tank. After being depressurized to atmospheric pressure, it enters the three-in-one filter for filtration. A small amount of depressurized ethylene is recovered and re-enters the reaction system. The polymers are filtered and intercepted in the three-in-one filter. The filtrates are combined and enter the distillation system. When a certain amount of polymers accumulates in the filter, another three-in-one filter is used, and the accumulated polymers are dried and discharged. This process is simple, efficient, environmentally friendly, and safe for online processing of polymers. Attached Figure Description

[0032] Figure 1 This is a schematic diagram of the structure of the ethylene oligomer processing device provided by the present invention. Detailed Implementation

[0033] The present invention provides a treatment device for ethylene oligomers, comprising a sedimentation filter, a pressure relief buffer tank, a three-in-one filter and a filtrate buffer tank connected in sequence.

[0034] See Figure 1 , Figure 1 This is a schematic diagram of the structure of the ethylene oligomer processing device provided by the present invention. Figure 1 In the diagram, 1 is a sedimentation filter, 2 is a pressure relief buffer tank, 3-1 and 3-2 are a three-in-one filter, and 4 is a filtrate buffer tank.

[0035] The device for treating ethylene oligomers provided by the present invention includes a settling filter, wherein the settling filter can be a pressure-resistant buffer tank with a high aspect ratio, wherein the aspect ratio of the settling filter is 10:1 to 2:1, preferably 10:1, 9:1, 8:1, 7:1, 6:1, 5:1, 4:1, 3:1, 2:1, or any value between 10:1 and 2:1.

[0036] In this invention, the settling filter comprises:

[0037] The flash-evaporated reaction liquid inlet with low polymer concentration is located in the middle of the side wall of the settling filter.

[0038] The clear liquid outlet is located at the top of the settling filter;

[0039] And a continuous discharge port for the mixed liquid located at the bottom of the settling filter.

[0040] Furthermore, a filter element is disposed at the upper part of the sedimentation filter. The pore size of the filter element is 0.1–200 micrometers, preferably 0.1, 1, 5, 10, 50, 100, 150, or 200 micrometers. Preferably, the filter element is a pressure-resistant support filter element, and the filter element structure includes one or more of sintered ceramic, stainless steel wound, and stainless steel spring types. The filter element has a large filtration area, ensuring that the clarified liquid after filtering is free of polymers. A clarified liquid outlet pipeline is provided at the top, and a flow control valve is installed. The settling filter has an inlet in the middle of its side wall. The reaction liquid with low polymer concentration after flash evaporation enters the settling filter through this inlet. Large polymer particles settle to the bottom, while a small number of fine particles are intercepted by the top filter element and remain in the settling filter. The settling filter has a continuous outlet for the mixed liquid at the bottom, and an outlet flow control valve is installed. The ratio of the clear liquid after filtration at the top to the reaction liquid containing polymers at the bottom is controlled by the top and bottom flow valves. This method achieves the initial concentration of the reaction liquid with low polymer concentration.

[0041] After passing through a settling filter, the concentration of polymers can be increased by 2 to 100 times, thereby reducing the difficulty of filtering pressurized reaction liquids. Most of the reaction liquids can be directly fed into the distillation system for separation after simple treatment, and only a small portion can be treated with atmospheric pressure equipment after depressurization.

[0042] The device for treating ethylene oligomers provided by the present invention further includes a pressure relief buffer tank connected to a settling filter, the pressure relief buffer tank comprising:

[0043] The mixed liquid inlet is located in the middle of the side wall of the pressure relief buffer tank, and the mixed liquid inlet is connected to the mixed liquid continuous outlet at the bottom of the settling filter;

[0044] An ethylene pressure relief port is provided at the top of the pressure relief buffer tank;

[0045] And a polymer mixture outlet located at the bottom of the pressure relief buffer tank.

[0046] Specifically, pressurized material (i.e., the mixture) enters the pressure relief buffer tank through the side mixture inlet. The inlet pressure can be 0.5-3 MPa, and the pressure inside the tank is 0.3-1 MPa. After being depressurized by the pressure relief buffer tank, the ethylene dissolved in the mixture overflows in gaseous form and is discharged through the top outlet of the buffer tank for reuse in the reaction section. The buffer tank is equipped with a liquid level detection device, and the pressure of the pressure relief buffer tank is controlled by the bottom outlet flow control valve.

[0047] The ethylene oligomer processing device provided by this invention also includes a three-in-one filter connected to a pressure relief buffer tank. The three-in-one filter is a pressurized filter, capable of performing functions such as sealed filtration, drying, and discharge.

[0048] The three-in-one filter includes:

[0049] The filter screen disposed on the inner side of the three-in-one filter has a pore size of 0.1 to 200 micrometers, preferably 0.1, 0.5, 1, 5, 10, 50, 100, 150, 200, or any value between 0.1 and 200 micrometers;

[0050] A stirring device is installed inside the three-in-one filter;

[0051] The liquid outlet is located at the bottom of the three-in-one filter;

[0052] A drying jacket device is installed on the outside of the three-in-one filter.

[0053] Specifically, the polymer mixture, pre-concentrated from the pressure relief buffer tank, enters the three-in-one filter for filtration. Solid-liquid separation is achieved by side and bottom filters. The liquid flows out from the bottom and enters the filtrate buffer tank, while the solids are trapped inside the three-in-one filter, which is equipped with a scraper agitator. When the pressure difference across the three-in-one filter reaches the set value, a standby three-in-one filter is switched on. Simultaneously, the switched-off filter is pressurized with nitrogen until no liquid flows out. Then, a heating medium is introduced into the jacket for high-density drying of the polymer. After high-density drying is completed, the solid material is discharged, and the equipment is ready for standby.

[0054] The device provided by this invention can realize the online enrichment, concentration, filtration, drying and discharge of reaction liquid with low polymer concentration, so as to realize the online external extraction of polymer and ensure the continuous operation of the device.

[0055] The present invention also provides a method for treating ethylene oligomers, comprising the following steps:

[0056] After flash evaporation, the reaction liquid with low polymer concentration under pressure is sequentially passed through a settling filter, a pressure relief buffer tank, and a three-in-one filter for solid-liquid separation. The resulting liquid enters the filtrate buffer tank, and the resulting solid is subjected to pressure filtration and drying to obtain ethylene oligomer.

[0057] Specifically, the method for treating oligomers in this invention focuses on the initial concentration of the reaction liquid with low polymer concentration through a settling filter, reducing the amount of reaction liquid requiring pressure relief, lowering the filtration difficulty, and enabling most high-pressure liquids to directly enter the distillation system for processing. The pressure is then reduced again through pressure relief to meet the operating conditions of the three-in-one filtration device. Through continuous material accumulation in the three-in-one device and the subsequent drying and discharge operation, the treatment of polymers has been transformed from high-pressure discharge, high moisture content, poor on-site environment, and manual operation to a continuous, automated, and environmentally friendly treatment method. The reaction liquid with low polymer concentration after flash evaporation is introduced into the settling filter through the side inlet. Most of the clear liquid is intercepted by the top filter element and settles on its own, with no polymer overflowing from the top to the distillation system for distillation separation. The bottom mixture with a polymer concentration of 1% to 10% enters the pressure relief buffer tank under pressure. In the pressure relief buffer tank, most of the ethylene dissolved in the mixture overflows from the liquid and is discharged from the top vapor outlet. The pressure of the pressure relief buffer tank is controlled by the top vapor valve. The bottom polymer mixture is introduced into the three-in-one filter from the bottom outlet of the tank. Solid-liquid separation is carried out in the three-in-one filter. The bottom liquid enters the filtrate buffer tank and is pumped into the distillation system. After the pressure difference of the three-in-one filter reaches the set value, it is pressure filtered and dried before being discharged, ultimately realizing the external transport of polymers.

[0058] Wherein, the mass concentration of polymer in the reaction solution with low polymer concentration under pressure after flash evaporation is 0.01% to 2%, preferably 0.01%, 0.03%, 0.05%, 0.1%, 0.3%, 0.5%, 0.8%, 1.0%, 1.5%, 2.0%, or any value between 0.01% and 2%;

[0059] The ratio of the upper clear liquid to the bottom mixed liquid discharged through the settling filter is 1:1 to 100:1, preferably 1:1, 5:1, 10:1, 20:1, 30:1, 40:1, 50:1, 60:1, 70:1, 80:1, 90:1, 100:1, or any value between 1:1 and 100:1;

[0060] The mass concentration of polymer in the mixture at the continuous discharge port of the mixture at the bottom of the settling filter is 1% to 10%, preferably 1%, 2%, 3%, 4%, 5%, 6%, 7%, 8%, 9%, 10%, or any value between 1% and 10%.

[0061] The pressure inside the pressure relief buffer tank is 0 to 0.5 MPa, preferably 0, 0.1, 0.2, 0.3, 0.4, 0.5, or any value between 0 and 0.5 MPa.

[0062] After being filtered by the three-in-one filter, the polymer is trapped in the filter, and the liquid is continuously discharged into the filtrate buffer tank, where it is pumped into the separation system for separation.

[0063] When the pressure difference across the three-in-one filter reaches 0.5 MPa, the feeding is stopped, and another three-in-one filter is switched to perform solid-liquid separation. The solid in the switched-off three-in-one filter is then subjected to nitrogen pressure filtration until the moisture content is 10-60%. A hot medium is then introduced into the jacket for drying until the moisture content is 0-10%. The material is then discharged and collected to obtain ethylene oligomer.

[0064] The reaction liquid containing polymers enters a high aspect ratio settling filter from the flash tank system after the reaction section. Most of the filtered reaction liquid overflows from the top of the settling filter into the distillation system for distillation separation. A small amount of high-polymer-concentration reaction liquid, after settling and interception filtration, flows through the bottom of the settling filter into a pressure relief buffer tank. After being depressurized to atmospheric pressure, it enters a three-in-one filter for filtration. A small amount of depressurized ethylene is recovered and re-enters the reaction system. The polymers are filtered and intercepted in the three-in-one filter, and the filtrates are combined and enter the distillation system. When a certain amount of polymers accumulates in the filter, another three-in-one filter is used, and the accumulated polymers are dried and discharged. This process for online polymer treatment is simple, efficient, environmentally friendly, and safe.

[0065] To further understand the present invention, the following description, in conjunction with embodiments, illustrates the processing apparatus and process for ethylene oligomers provided by the present invention. The scope of protection of the present invention is not limited by the following embodiments.

[0066] Example 1:

[0067] The ethylene oligomerization reaction liquid, after flash evaporation, mainly consists of cyclohexane, ethylene, 1-butene, 1-hexene, 1-octene, cyclohexane, C12 olefins, C14 olefins, C16 olefins, and C18 olefins, etc., containing 0.042% insoluble polymers by mass. The pressure after flash evaporation is 1.7 MPa, and the flow rate is 510 L / h. The liquid is introduced into a settling filter (effective volume 1000 L, height-to-diameter ratio 3.3, inlet located in the middle of the side, top with 24 sintered metal filter elements, filter element pore size 20 micrometers). The flow rate is controlled by top and bottom control valves, with the top discharge from the settling filter at 490 L / h and the bottom at 490 L / h. The feed rate is 20L / h. The top feed enters the pre-buffer tank of the distillation system, and the bottom feed enters the pressure relief buffer tank. The pressure inside the pressure relief buffer tank is controlled at 0.5 MPa through the gas phase valve at the top, and the liquid level in the pressure relief buffer tank is controlled at 60%. The liquid at the bottom of the pressure relief buffer tank is self-pressurized into a 50L three-in-one filter. The filtrate is discharged into the filtrate buffer tank and intermittently pumped into the pre-buffer tank of the distillation system. After the single filter has been running for 27 hours, the pressure difference of the three-in-one filter (filter element pore size 20 microns) reaches 0.27 MPa. After running for 51 hours, the pressure difference reaches 0.48 MPa, and then another three-in-one filter is switched on. The switched three-in-one filter is subjected to nitrogen pressure filtration at 0.65 MPa until no liquid flows out. Then, 90℃ circulating hot water is introduced into the jacket for high-temperature drying. After drying for 7 hours, the product is discharged, yielding 7.8 kg of loose white powder dry solid, which is bagged and sent for external processing. After running for 58 hours, the pressure difference across the three-in-one filter reached 0.47 MPa. The filter was then switched to a drying process, which also yielded 8.9 kg of loose white powder dry solid.

[0068] Example 2:

[0069] The ethylene tetramerization reaction liquid, after flash evaporation, mainly consists of cyclohexane, 1-hexene, 1-octene, decene, C12 ene, and C14 ene, among others, containing 0.102% insoluble polymers by mass. The pressure after flash evaporation is 1.7 MPa, and the flow rate is 360 L / h. The liquid is introduced into a settling filter (effective volume 1000 L, height-to-diameter ratio 3.3, inlet located in the middle of the side, top with 24 sintered metal filter elements, each with a pore size of 20 micrometers). Control valves at the top and bottom regulate the flow rate of the settling filter, with a top discharge rate of 340 L / h and a bottom discharge rate of 15 L / h. The top discharge enters the pre-buffer tank of the distillation system, and the bottom discharge enters the pressure relief buffer tank. The pressure inside the pressure relief buffer tank is controlled at 0.5 MPa through the gas phase valve at the top, and the liquid level in the pressure relief buffer tank is controlled at 60%. The liquid at the bottom of the pressure relief buffer tank is self-pressurized into a 50L three-in-one filter. The filtrate is discharged into the filtrate buffer tank and intermittently pumped into the pre-buffer tank of the distillation system. After the single filter has been running for 14 hours, the pressure difference of the three-in-one filter (filter element pore size 20 microns) reaches 0.24 MPa. After running for 20 hours, the pressure difference reaches 0.46 MPa, and then another three-in-one filter is switched on. The switched three-in-one filter is subjected to nitrogen pressure filtration at 0.65 MPa until no liquid flows out. Then, 90℃ circulating hot water is introduced into the jacket for drying. After drying for 9 hours, the material is discharged, yielding 7.4 kg of loose white powdery dry solid, which is bagged and sent for external processing. After running for 21 hours, the pressure difference across the three-in-one filter reached 0.47 MPa. The filter was then switched to a drying process, which also yielded 7.6 kg of loose white powder dry solid.

[0070] Comparative Example 1:

[0071] The reaction solution composition, pressure, and flow rate were the same as in Example 1. After flash evaporation, a belt filter (four sets of 10L filter bags with 20-micron pore size) was used for filtration. After 37 hours of operation, the pressure difference across the filter reached 0.51 MPa. The standby bag filter was then switched to, and the belt filter was manually disassembled after nitrogen purging. 9.7 kg of wet material containing a large amount of solvent was removed, resulting in a strong odor and making the operation difficult.

[0072] Comparative Example 2:

[0073] The composition, pressure, and flow rate of the reaction solution were the same as in Example 2. After flash evaporation, a belt filter (four sets of 10L filter bags with 20-micron pore size) was used for filtration. After 14 hours of operation, the pressure difference before and after the filter reached 0.44 MPa. The standby bag filter was then switched to, and the belt filter was manually disassembled after nitrogen purging. 8.7 kg of wet material was removed. The operation was difficult and the environmental requirements could not be met on site.

[0074] The above description is only a preferred embodiment of the present invention. It should be noted that for those skilled in the art, several improvements and modifications can be made without departing from the principle of the present invention, and these improvements and modifications should also be considered within the scope of protection of the present invention.

Claims

1. An apparatus for treating ethylene oligomerization polymers, characterized by, It includes a sedimentation filter, a pressure relief buffer tank, a three-in-one filter, and a filtrate buffer tank connected in sequence; the height-diameter ratio of the sedimentation filter is 10:1 to 2:1; The sedimentation filter includes: A reaction liquid inlet with low pressure and high polymer concentration after flash evaporation, which is arranged in the middle of the side wall of the sedimentation filter; A clear liquid outlet arranged at the top of the sedimentation filter; And a continuous discharge port for the mixed liquid arranged at the bottom of the sedimentation filter; A filter element is arranged at the upper part inside the sedimentation filter, and the pore diameter of the filter element is 0.1 to 200 microns; The mass concentration of the polymer in the reaction liquid with low pressure and high polymer concentration after flash evaporation is 0.01% to 2%; The discharge ratio of the upper clear liquid to the bottom mixed liquid passing through the sedimentation filter is 1:1 to 100:1; The mass concentration of the polymer in the mixed liquid continuously discharged from the continuous discharge port of the mixed liquid at the bottom of the sedimentation filter is 1% to 10%. After passing through the sedimentation filter, the concentration of the polymer can be increased by 2 to 100 times.

2. The processing device of claim 1, wherein, The pressure relief buffer tank includes: A mixed liquid inlet arranged in the middle of the side wall of the pressure relief buffer tank, and the mixed liquid inlet is connected to the continuous discharge port of the mixed liquid at the bottom of the sedimentation filter; An ethylene pressure relief port arranged at the top of the pressure relief buffer tank; And a polymer mixture discharge port arranged at the bottom of the pressure relief buffer tank.

3. The processing device of claim 1, wherein, The three-in-one filter includes: A filter screen arranged at the inner side position of the three-in-one filter, and the pore diameter of the filter screen is 0.1 to 200 microns; A stirring device arranged inside the three-in-one filter; A liquid discharge port arranged at the bottom of the three-in-one filter; A drying jacket device arranged outside the three-in-one filter.

4. A process for the treatment of ethylene oligomerization polymers, characterized in that, It includes the following steps: The reaction liquid with low pressure and high polymer concentration after flash evaporation is sequentially passed through the sedimentation filter, the pressure relief buffer tank, and the three-in-one filter for solid-liquid separation. The obtained liquid enters the filtrate buffer tank, and the obtained solid is subjected to pressure filtration and drying to obtain ethylene oligomer polymer.

5. The treatment method according to claim 4, characterized in that, The mass concentration of the polymer in the reaction liquid with low pressure and high polymer concentration after flash evaporation is 0.01% to 2%; The discharge ratio of the upper clear liquid to the bottom mixed liquid passing through the sedimentation filter is 1:1 to 100:1; The mass concentration of the polymer in the mixed liquid continuously discharged from the continuous discharge port of the mixed liquid at the bottom of the sedimentation filter is 1% to 10%.

6. The treatment method of claim 4, wherein The pressure inside the pressure relief buffer tank is 0 to 0.5 Mpa.

7. The treatment method of claim 4, wherein After being filtered by the three-in-one filter, the polymer is intercepted in the filter, and the liquid is continuously discharged into the filtrate buffer tank and pumped into the separation system for separation; When the pressure difference before and after the three-in-one filter reaches 0.5 Mpa, the feeding is stopped, and another three-in-one filter is switched for solid-liquid separation. The solid in the three-in-one filter that has been switched off is subjected to nitrogen pressure filtration until the moisture content is 10 - 60%, and then a heat medium is introduced into the jacket for drying until the moisture content is 0 - 10%, and then the product is discharged and collected to obtain ethylene oligomer polymer.

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