An oligomer removal system, removal method, and oligomer precipitation tank

Abstract

This invention provides an oligomer removal system and method, as well as an oligomer precipitation tank. The oligomer precipitation tank includes: a cylindrical shell; a first baffle, a second baffle, and a third baffle sequentially disposed on the inner wall of the shell, the first baffle, the second baffle, and the third baffle forming a first angle, a second angle, and a third angle with the central axis of the shell, respectively, the first angle being greater than or equal to 0° and less than or equal to 15°; a hot material injection port and a cold material injection port disposed on the shell; wherein, in the axial direction of the shell, the hot material injection port and the cold material injection port are lower than the highest point of the first baffle and the highest point of the third baffle, respectively, and the hot material injection port and the cold material injection port are higher than the highest point of the second baffle. The use of the oligomer precipitation tank of this invention increases radial stirring, avoiding problems such as the precipitated oligomers clogging the device pipeline, entanglement, or adhesion to the stirring device.

Description

Technical Field

[0001] This invention belongs to the field of low-carbon olefin production from ethylene oligomerization in the chemical industry, and relates to an oligomer removal system and removal method, as well as an oligomer precipitation tank. Background Technology

[0002] 1-Hexene is an important comonomer for the production of high-performance high-density polyethylene (HDPE) and linear low-density polyethylene (LLDPE). Polyethylene resins produced using 1-hexene as a comonomer exhibit excellent tensile strength and tear resistance, significantly improving the quality of polyethylene resins. 1-Hexene is primarily used as a comonomer for polyethylene in Europe and the United States. Simultaneously, 1-hexene is also an important organic chemical raw material for the production of high-grade lubricants, plasticizers, surfactants, and other fine chemicals, with a wide range of applications and high added value.

[0003] Currently, oligomers generated during the industrial production of 1-hexene dissolve in the heavy component material at the bottom of the decene tower. The main components of the bottom material are small amounts of decene, isooctanol, C12-C14 olefins, and low molecular weight polyethylene. The temperature of the material inside the tower is between 180℃ and 200℃. Industrially, traditional heat exchangers are used for cooling. When the tower temperature decreases, the oligomers in the material easily precipitate and adhere to the surface of the heat exchanger tubes, reducing heat exchange efficiency and clogging the equipment pipelines. Therefore, regular cleaning of the heat exchangers and equipment pipelines is required, consuming significant manpower and resources. Furthermore, the presence of oligomers prevents the terminating agent in the heavy component from being recycled, forcing it to be discharged as fuel, resulting in substantial waste of raw materials.

[0004] Currently, there is no research or report on methods for removing oligomers in 1-hexene production, either domestically or internationally. CN203425821U discloses a device for continuously precipitating polymers from solution, which achieves solid-liquid separation through a precipitation tank. A stirrer is installed along the axis of the precipitation tank for stirring, and a porous plate with precipitation holes is installed at the top of the tank to ensure good polymer precipitation. However, when this technology is used for polymer precipitation, the polymer tends to entangle or adhere to the stirrer surface, making further solid-phase separation difficult.

[0005] Therefore, further research is needed in this field on the removal of oligomers during 1-hexene production. Summary of the Invention

[0006] This invention provides an oligomer removal system, a removal method, and an oligomer precipitation tank to overcome the operational difficulties in the production of 1-hexene caused by oligomer blockage in pipelines, entanglement, or adhesion to the stirring device.

[0007] To achieve the above objectives, the present invention provides an oligomer precipitation tank, comprising:

[0008] The shell is cylindrical.

[0009] A first baffle, a second baffle, and a third baffle are sequentially disposed on the inner wall of the housing. The first baffle, the second baffle, and the third baffle are respectively at a first angle, a second angle, and a third angle with the central axis of the housing. The first angle, the second angle, and the third angle are greater than or equal to 0° and less than or equal to 15°.

[0010] Hot material injection port and cold material injection port are located in the housing;

[0011] In the axial direction of the housing, the hot material injection port and the cold material injection port are lower than the highest point of the first baffle and the highest point of the third baffle, while the hot material injection port and the cold material injection port are higher than the highest point of the second baffle.

[0012] The oligomer precipitation tank of the present invention is wherein the hot material injection port and the cold material injection port are symmetrically arranged with respect to the extended surface of the second baffle; the hot material entering the shell through the hot material injection port and the cold material entering the shell through the cold material injection port collide on the second baffle or the extended surface of the second baffle.

[0013] The oligomer precipitation tank of the present invention, wherein the first baffle, the second baffle and the third baffle are parallel to the central axis of the shell; in the radial section of the shell, the extension line of the first baffle is at 90° with the extension line of the second baffle, and the extension line of the second baffle is at 90° with the extension line of the third baffle.

[0014] In the oligomer precipitation tank of the present invention, the hot material injection port and the cold material injection port are disposed on the side of the first baffle and the third baffle that is different from the second baffle.

[0015] The oligomer precipitation tank of the present invention, wherein the extended surface of the second baffle intersects the shell in a straight line, and the shell has a cross-section through the straight line, the direction of the hot material injection port forms a fourth angle with the cross-section, and the direction of the cold material injection port forms a fifth angle with the cross-section, wherein both the fourth angle and the fifth angle are greater than 0 degrees and less than or equal to 15 degrees.

[0016] In the oligomer precipitation tank of the present invention, the widths of the first baffle, the second baffle, and the third baffle in the radial direction of the shell are 1 / 10 to 1 / 15 of the diameter of the shell.

[0017] To achieve the above objectives, the present invention also provides an oligomer removal system for removing oligomers in industrial 1-hexene production, comprising:

[0018] decene tower;

[0019] A first cooling device is connected to the decene tower to transport the hot material at the bottom of the decene tower to the first cooling device for initial cooling.

[0020] An oligomer precipitation tank is connected to the first cooling device;

[0021] The filtration device is connected to the oligomer precipitation tank;

[0022] A storage device for a mixture of decanol is connected to the filtration device;

[0023] The second cooling device is connected to the decanol mixture storage device and the oligomer precipitation tank, respectively.

[0024] The hot material at the bottom of the decene tower is cooled by the first cooling device and then transported to the oligomer precipitation tank, where it is mixed with the decyl alcohol mixture cooled by the second cooling device to precipitate oligomer particles.

[0025] The oligomer removal system of the present invention, wherein the oligomer precipitation tank is the oligomer precipitation tank described above.

[0026] The oligomer removal system of the present invention includes a decene tower bottom pump between the decene tower and the first cooling device for pressurizing the hot material at the bottom of the decene tower; and a decene alcohol mixture storage tank pump between the decene alcohol mixture storage device and the second cooling device for pressurizing the decene alcohol mixture in the decene alcohol mixture storage device.

[0027] In the oligomer removal system of the present invention, a diversion pipeline is further provided between the decanol mixture storage tank pump and the second cooling device to discharge part of the decanol mixture from the system.

[0028] To achieve the above objectives, the present invention further provides a method for removing oligomers in the industrial production of 1-hexene, comprising:

[0029] Step 1: Cool the hot material containing oligomers to obtain the first cooled material;

[0030] Step 2: The first cooled material is colliding and mixing with the cold material to precipitate oligomers;

[0031] Step 3: Perform solid-liquid separation on the mixture obtained in Step 2 to obtain oligomers and a liquid phase from which the oligomers have been removed;

[0032] The temperature of the first cooling material is 90℃~110℃, and the temperature of the cold material is 10℃~20℃.

[0033] The oligomer removal method of the present invention further includes:

[0034] Step 4: Cool part or all of the liquid phase from which oligomers have been removed to 10°C to 20°C, and use it as the cold material.

[0035] The oligomer removal method of the present invention includes a first cooling material being pressurized to not less than 1.2 MPa and a flow rate of 3 to 5 m / s, and a cold material being pressurized to not less than 1.2 MPa and a flow rate of 3 to 5 m / s, and then the first cooling material and the cold material are mixed by collision.

[0036] The beneficial effects of this invention are:

[0037] This invention involves mixing hot materials cooled to 90℃~110℃ with cold materials at 10℃~20℃. The mixture is then cooled to a specific temperature (18℃~30℃) in a precipitation tank, causing the oligomers to precipitate completely in a particulate state, preventing them from agglomerating and ensuring smooth material discharge without pipeline blockage. The precipitated oligomers are then removed using a filter, and the cooled material is recycled as cold material.

[0038] Since the temperature of the hot material inside the tower is usually between 180℃ and 200℃, and the melting point of oligomers in organic materials is generally above 90℃, the hot material is first cooled to 90℃ to 110℃ in order to initially control the temperature of the oligomers to not be lower than 90℃ and prevent precipitation. Then it is mixed with cold material at 10℃ to 20℃, and the temperature naturally drops to 18℃ to 30℃ before precipitation. This can greatly save the amount of chilled water and electricity used, thereby reducing energy consumption and saving economic costs.

[0039] The use of the oligomer precipitation tank of this invention replaces the traditional heat exchanger in the prior art. By spraying and colliding hot and cold materials, or by colliding hot and cold materials with baffles, radial stirring is increased, so that hot and cold materials can form a mixing vortex stirring in the tank. This avoids problems such as the precipitation of oligomers clogging the device pipeline, entanglement or adhesion to the stirring device. Attached Figure Description

[0040] Figure 1 This is a schematic diagram of the oligomer removal system in the 1-hexene production apparatus of the present invention.

[0041] Figure 2 This is a top view of the oligomer precipitation tank of the present invention.

[0042] Figure 3 This is a front view schematic diagram of the oligomer precipitation tank of the present invention.

[0043] In the attached figures, the following labels are used:

[0044] 1. Decene Tower

[0045] 2-decene bottom pump

[0046] 3 First cooling device

[0047] 4. Oligomer precipitation tank

[0048] 41 Casing

[0049] 42 First baffle

[0050] 43 Second baffle

[0051] 44 Third baffle

[0052] 45 Hot material injection nozzle

[0053] 46 Cold Material Injection Nozzle

[0054] 47 cross-sections

[0055] 5 Filtration Device

[0056] 5-1 First Filtering Device

[0057] 5-2 Second Filter Device

[0058] Storage device for 6-decyl alcohol mixture

[0059] 7-decyl alcohol mixture storage tank pump

[0060] 8 Second cooling device Detailed Implementation

[0061] The technical solution of the present invention will be described in detail below. The following embodiments are implemented under the premise of the technical solution of the present invention and a detailed implementation process is given. However, the protection scope of the present invention is not limited to the following embodiments. Structures or experimental methods that do not specify specific conditions in the following embodiments are generally performed under conventional conditions.

[0062] This invention provides an oligomer removal system for removing oligomers from mixtures containing oligomers. The oligomers are, for example, low molecular weight polyethylene with a molecular weight of, for example, 500–10,000. In one embodiment, the oligomer removal system of this invention can be used for removing oligomers in industrial 1-hexene production. Further, the oligomers generated in industrial 1-hexene production are dissolved in the bottom heavy component of a decene tower. The bottom component mainly consists of small amounts of decene, isooctanol, C12–C14 olefins, and low molecular weight polyethylene. The temperature of the material inside the tower is between 180°C and 200°C.

[0063] like Figure 1As shown, the oligomer removal system of the present invention includes a decene tower 1, a first cooling device 3, an oligomer precipitation tank 4, a filtration device 5, a decyl alcohol mixture storage device 6, and a second cooling device 8.

[0064] The first cooling device 3 is connected to the decene tower 1 to transport the hot material at the bottom of the decene tower 1 to the first cooling device 3 for initial cooling. The hot material at the bottom of the decene tower 1 may contain, for example, dissolved oligomers generated during the production of industrial 1-hexene. The oligomer precipitation tank 4 is connected to the first cooling device 3. The filtration device 5 is connected to the oligomer precipitation tank 4. The decanol mixture storage device 6 is connected to the filtration device 5. The second cooling device 8 is connected to both the decanol mixture storage device 6 and the oligomer precipitation tank 4.

[0065] The hot material at the bottom of the decene tower is cooled by the first cooling device 3 and then transported to the oligomer precipitation tank 4, where it is mixed with the decyl alcohol mixture cooled by the second cooling device 8 to precipitate oligomer particles.

[0066] This invention involves initially cooling the hot material and then mixing it with the cold material from which oligomers have been removed. The mixture is then allowed to cool naturally to 18°C–30°C, causing the oligomers to precipitate. This stepwise cooling process not only prevents the oligomers from agglomerating but also saves on the amount of chilled water and electricity consumed, thereby reducing energy consumption and saving economic costs.

[0067] In one embodiment, a decene tower bottom pump 2 is also provided between the decene tower 1 and the first cooling device 3 to pressurize the hot material at the bottom of the decene tower; a decyl alcohol mixture storage tank pump 7 is also provided between the decyl alcohol mixture storage device 6 and the second cooling device 8 to pressurize the decyl alcohol mixture in the decyl alcohol mixture storage device 6. When the pressurized hot material and the decyl alcohol mixture cold material are mixed in the oligomer precipitation tank 4, they can impact the liquid in the tank, thereby playing a stirring role, which is conducive to the heat transfer of hot and cold materials, avoiding the use of a stirring device, and thus preventing the precipitated oligomers from adhering to or entangled in the stirring device, causing operational difficulties.

[0068] In one embodiment, a diversion line is also provided between the decanol mixture storage tank pump 6 and the second cooling device 8 to discharge a portion of the decanol mixture from the system. In another embodiment, the pipeline connecting the first cooling device 3 and the oligomer precipitation tank 4 is also connected to the decene tower 1 to circulate a portion of the cooled hot material back to the decene tower 1.

[0069] In one embodiment, the filtration device 5 of the present invention includes a first filtration device 5-1 and a second filtration device 5-2 arranged in series to achieve efficient filtration of the mixture in the oligomer precipitation tank 4, but the present invention is not limited thereto.

[0070] In one embodiment, during the start-up phase of the oligomer removal system of the present invention, materials free of oligomers from the outside environment can be used. After being cooled by the decanol mixture storage tank pump 7 into the second cooling device 8, the materials can be used as the cold materials of the present invention.

[0071] In one embodiment, the oligomer precipitation tank of the present invention is as follows: Figure 2 and 3 As shown, it includes a housing 41, a first baffle 42, a second baffle 43, a third baffle 44, a hot material injection port 45, and a cold material injection port 46.

[0072] The housing 41 is cylindrical, and a first baffle 42, a second baffle 43, and a third baffle 44 are sequentially disposed on the inner wall of the housing 41. Further, the first baffle 42, the second baffle 43, and the third baffle 44 are vertical baffles disposed within the housing 41, i.e., baffles disposed along the axial direction of the housing 41. In one embodiment, the first baffle 42, the second baffle 43, and the third baffle 44 form a first angle, a second angle, and a third angle with the central axis of the housing 41, respectively, where the first angle is greater than or equal to 0° and less than or equal to 15°. In another embodiment, the first baffle 42, the second baffle 43, and the third baffle 44 are parallel to the central axis of the housing 41.

[0073] In one embodiment, in the radial cross-section of the housing 41, the extension line of the first baffle 42 is at 90° to the extension line of the second baffle 43, and the extension line of the second baffle 43 is at 90° to the extension line of the third baffle 44; that is, the first baffle 42 and the third baffle 44 form a plane that passes through the central axis of the housing 41, and the extension surface of the second baffle 43 also passes through the central axis of the housing 41.

[0074] In one embodiment, the widths of the first baffle 42, the second baffle 43, and the third baffle 44 of the present invention in the radial direction of the housing 41 are 1 / 10 to 1 / 15 of the diameter of the housing 41. The diameter of the housing 41 is the diameter of the bottom or top circle of the cylinder.

[0075] In this invention, the hot material injection port 45 and the cold material injection port 46 are disposed on the shell. In the axial direction of the shell 41, the hot material injection port 45 and the cold material injection port 46 are lower than the highest point of the first baffle 42 and the highest point of the third baffle 44, and higher than the highest point of the second baffle 43. This arrangement allows the hot and cold materials to easily rotate and collide with the baffles after entering the shell, increasing mass and heat transfer within the oligomer precipitation tank. Simultaneously, the collision of the hot and cold materials also enables rapid mixing.

[0076] The present invention increases radial stirring by allowing hot and cold materials to enter the shell through hot material injection port 45 and cold material injection port 46, which spray and collide with each other, or by allowing hot and cold materials to collide with the baffle. This enables the hot and cold materials to form a mixing vortex in the tank, avoiding problems such as precipitated oligomers clogging the device pipeline, entanglement or adhesion of the stirring device.

[0077] In one embodiment, the hot material injection port 45 and the cold material injection port 46 are symmetrically arranged with respect to the extended surface of the second baffle 43; the hot material entering the housing 41 through the hot material injection port 45 collides with the cold material entering the housing 41 through the cold material injection port 46 on the second baffle 43 or the extended surface of the second baffle 43, thereby playing a stirring role.

[0078] In other words, the arrangement of the hot material injection port 45 and the cold material injection port 46 allows the hot and cold materials entering through them to meet at a certain position inside the shell, thereby causing a collision.

[0079] In one embodiment, the hot material injection port 45 and the cold material injection port 46 of the present invention are disposed on the side of the first baffle 42 and the third baffle 44 that is different from the second baffle 43. That is, the hot material injection port 45 and the cold material injection port 46 are disposed on both sides of the plane formed by the first baffle 42 and the third baffle 44, respectively. This allows the hot and cold materials to collide towards each other, so that the hot and cold materials can be mixed quickly. At the same time, the hot and cold materials can be swirled, increasing the collision with the baffles, strengthening the mixing degree in the reactor, and allowing the hot materials to cool down quickly and the low molecular weight polymers to precipitate quickly.

[0080] In one embodiment, the extended surface of the second baffle 43 intersects the housing 41 along a straight line. Passing through this straight line, the housing has a tangential surface 47. The direction of the hot material injection port 45 forms a fourth angle θ with the tangential surface 47, and the direction of the cold material injection port 46 forms a fifth angle α with the tangential surface 47. Both the fourth angle θ and the fifth angle α are greater than 0 degrees and less than or equal to 15 degrees. This allows the direction in which hot and cold materials are injected into the housing to be closer to the tangential angle, which is beneficial for material rotation.

[0081] In one embodiment, when the oligomer removal system of the present invention is used in a cycle, the oligomer precipitation tank 4 always contains liquid. At this time, the hot material injection port 45 and the cold material injection port 46 are located below the liquid surface, which can create an impact effect on the inside of the liquid and promote the flow of the liquid.

[0082] The present invention does not specifically limit the length of the first baffle 42, the second baffle 43, and the third baffle 44 in the axial direction of the housing 41. For example, the first baffle 42 and the third baffle 44 are located in the middle of the housing (in the middle of the axial direction of the housing), and the second baffle 42 extends to the bottom of the housing 41.

[0083] This invention also provides a method for removing oligomers in industrial 1-hexene production, comprising:

[0084] Step 1: Cool the hot material containing oligomers to obtain the first cooled material;

[0085] Step 2: The first cooled material is colliding and mixing with the cold material to precipitate oligomers;

[0086] Step 3: Perform solid-liquid separation on the mixture obtained in Step 2 to obtain oligomers and a liquid phase from which the oligomers have been removed;

[0087] The temperature of the first cooling material is 90℃~110℃, and the temperature of the cold material is 10℃~20℃.

[0088] This invention mixes hot materials cooled to 90℃~110℃ with cold materials at 10℃~20℃. The mixture is then allowed to cool naturally to a certain temperature (18℃~30℃) in a precipitation tank, where oligomers are completely precipitated in a microparticle state. The oligomers do not clump together, ensuring smooth material discharge and preventing pipeline blockage.

[0089] In one embodiment, the oligomer removal method of the present invention further includes:

[0090] Step 4: Cool part or all of the liquid phase from which oligomers have been removed to 10°C to 20°C, and use it as the cold material.

[0091] Since the temperature of hot materials is usually between 180℃ and 200℃, and the melting point of oligomers in organic materials is generally above 90℃, the hot materials are first cooled to 90℃ to 110℃ to initially control the temperature of the oligomers to not be lower than 90℃ and prevent precipitation. Then, they are mixed with circulating cold materials at 10℃ to 20℃, and the temperature naturally drops to 18℃ to 30℃ before precipitation. This can greatly save on the amount of chilled water and electricity used, thereby reducing energy consumption and saving economic costs.

[0092] In one embodiment, the first cooling material is pressurized to a pressure of not less than 1.2 MPa and a flow rate of 3-5 m / s, while the cold material is pressurized to a pressure of not less than 1.2 MPa and a flow rate of 3-5 m / s. The first cooling material and the cold material then collide and mix. This increases the degree of collision between the two materials, promotes the flow of the mixture, and better achieves the mixing effect.

[0093] The oligomer removal method of the present invention is applicable to the above-mentioned oligomer removal system. In one specific embodiment, the removal steps are as follows:

[0094] The hot material at the bottom of the decene tower 1 is pressurized by the decene tower bottom pump 2 and enters the first cooling device 3. After cooling the hot material to a certain temperature, it is sprayed into the oligomer precipitation tank 4 and directly mixed with the cold material. After sufficient heat transfer in the oligomer precipitation tank 4, the oligomers are completely precipitated. The mixture then enters the filtration device 5. The decyl alcohol mixture obtained after filtering the oligomers enters the decyl alcohol mixture storage device 6. A portion of the decyl alcohol mixture is pressurized by the decyl alcohol mixture storage tank pump 7 and cooled to a certain temperature by the second cooling device 8 before being sprayed into the oligomer precipitation tank 4 as a mixture of cold and hot materials. The oligomer precipitation tank 4 is equipped with baffles. Both the cold and hot materials are sprayed into the oligomer precipitation tank 4 at a small angle to the tangent and under pressure. Under the action of the baffles in the oligomer precipitation tank 4, they are fully mixed, and the temperature of the mixture decreases, thereby achieving complete precipitation.

[0095] In one embodiment, the hot material is cooled to 90°C–110°C by the first cooling device 3, and then pressurized to a pressure of not less than 1.2 MPa and a flow rate of 3–5 m / s by the decene bottom pump 2. The cold material has a temperature of 10°C–20°C, a pressure of not less than 1.2 MPa, and a flow rate of 3–5 m / s. After the hot and cold materials are mixed in the oligomer precipitation tank 4, the temperature is 18°C–30°C, and the oligomers are completely precipitated.

[0096] After being pressurized by the decanol mixture storage tank pump 7 and cooled to 10℃~20℃ by the second cooling device 8, with a pressure of not less than 1.2MPa and a flow rate of 3~5m / s, a portion of the decanol mixture can be used as a cold material to mix with the hot material.

[0097] The present invention also provides a specific embodiment, as follows:

[0098] In the 1-hexene unit, when the actual bottom temperature of the decene column is 193°C, the material is pressurized to 0.6 MPa by the bottom pump, cooled to 90°C by the first cooling device, and then injected into the oligomer precipitation tank at a 15-degree angle to the tangent at a flow rate of 5 m / s. The decanol mixture after oligomer removal is cooled to 15°C and also injected into the oligomer precipitation tank at a 15-degree angle to the tangent, with a pressure of 0.6 MPa and a flow rate of 5 m / s. The hot and cold materials are thoroughly mixed in the oligomer precipitation tank, and the material is cooled to approximately 30°C, at which point the oligomers precipitate in the form of particulate matter.

[0099] The precipitated oligomers enter a filtration device from the bottom of the oligomer precipitation tank for removal. The filtered material then enters a decanol mixture storage device. A portion of the material is pressurized to 1.0 MPa by a pump from the bottom of the decanol mixture storage device, then cooled to 15°C by a second cooling device. This cooled material is then circulated back into the oligomer precipitation tank via a 15-degree angled jet, ensuring thorough mixing with the hot material. A portion of the oligomers obtained from the filtration device can be used as a terminator or discharged.

[0100] Of course, the present invention may have other various embodiments. Without departing from the spirit and essence of the present invention, those skilled in the art can make various corresponding changes and modifications according to the present invention, but these corresponding changes and modifications should all fall within the protection scope of the claims of the present invention.

Claims

1. An oligomer precipitation tank, characterized in that, include: The shell is cylindrical. A first baffle, a second baffle, and a third baffle are sequentially disposed on the inner wall of the housing. The first baffle, the second baffle, and the third baffle are respectively at a first angle, a second angle, and a third angle with the central axis of the housing. The first angle, the second angle, and the third angle are greater than or equal to 0° and less than or equal to 15°. Hot material injection port and cold material injection port are disposed in the housing, and the hot material injection port and the cold material injection port are disposed on the side of the first baffle and the third baffle that is different from the second baffle; In the axial direction of the housing, the hot material injection port and the cold material injection port are lower than the highest point of the first baffle and the highest point of the third baffle, and the hot material injection port and the cold material injection port are higher than the highest point of the second baffle. The hot material entering the shell through the hot material injection port collides with the cold material entering the shell through the cold material injection port on the second baffle or the extended surface of the second baffle. The extended surface of the second baffle intersects the shell in a straight line. The shell has a cross surface through the straight line. The direction of the hot material injection port forms a fourth angle with the cross surface, and the direction of the cold material injection port forms a fifth angle with the cross surface. Both the fourth angle and the fifth angle are greater than 0 degrees and less than or equal to 15 degrees.

2. The oligomer precipitation tank according to claim 1, characterized in that, The hot material injection port and the cold material injection port are symmetrically arranged with respect to the extended surface of the second baffle.

3. The oligomer precipitation tank according to claim 2, characterized in that, The first baffle, the second baffle, and the third baffle are parallel to the central axis of the housing; in the radial section of the housing, the extension line of the first baffle is at 90° with the extension line of the second baffle, and the extension line of the second baffle is at 90° with the extension line of the third baffle.

4. The oligomer precipitation tank according to claim 1, characterized in that, In the radial direction of the housing, the widths of the first baffle, the second baffle, and the third baffle are 1 / 10 to 1 / 15 of the diameter of the housing.

5. An oligomer removal system, characterized in that, Used for the removal of oligomers in industrial 1-hexene production, including: decene tower; A first cooling device is connected to the decene tower to transport the hot material at the bottom of the decene tower to the first cooling device for initial cooling. An oligomer precipitation tank is connected to the first cooling device; The filtration device is connected to the oligomer precipitation tank; A storage device for a mixture of decanol is connected to the filtration device; The second cooling device is connected to the decanol mixture storage device and the oligomer precipitation tank, respectively. The hot material at the bottom of the decene tower is cooled by the first cooling device and then transported to the oligomer precipitation tank, where it is mixed with the decyl alcohol mixture cooled by the second cooling device to precipitate oligomer particles. Wherein, the oligomer precipitation tank is the oligomer precipitation tank according to any one of claims 1-4.

6. The oligomer removal system according to claim 5, characterized in that, A decene tower bottom pump is also provided between the decene tower and the first cooling device for pressurizing the hot material at the bottom of the decene tower; a decene alcohol mixture storage tank pump is also provided between the decene alcohol mixture storage device and the second cooling device for pressurizing the decene alcohol mixture in the decene alcohol mixture storage device.

7. The oligomer removal system according to claim 6, characterized in that, A diversion line is also provided between the decanol mixture storage tank pump and the second cooling device to discharge part of the decanol mixture from the system.

8. A method for removing oligomers, characterized in that, The oligomer removal system according to any one of claims 5-7, the oligomer removal method for removing oligomers in industrial 1-hexene production, includes: Step 1: Cool the hot material containing oligomers to obtain the first cooled material; Step 2: The first cooled material is colliding and mixing with the cold material to precipitate oligomers; Step 3: Perform solid-liquid separation on the mixture obtained in Step 2 to obtain oligomers and a liquid phase from which the oligomers have been removed; The temperature of the first cooling material is 90℃~110℃, and the temperature of the cold material is 10℃~20℃.

9. The oligomer removal method according to claim 8, characterized in that, Also includes: Step 4: Cool part or all of the liquid phase from which oligomers have been removed to 10°C to 20°C, and use it as the cold material.

10. The oligomer removal method according to claim 8, characterized in that, The first cooling material is pressurized to a pressure of not less than 1.2 MPa and a flow rate of 3 to 5 m / s, and the cold material is pressurized to a pressure of not less than 1.2 MPa and a flow rate of 3 to 5 m / s. Then the first cooling material and the cold material collide and mix.

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