Continuous polymerization method and system of PAO

Abstract

The invention provides a continuous polymerization method and system of PAO. The continuous polymerization method of the PAO comprises the following steps: firstly, premixing a gas-phase catalyst, an auxiliary agent and part of polymerization raw materials twice, and then mixing the obtained mixture with the residual polymerization raw materials for polymerization reaction to obtain the PAO, wherein the second premixing is carried out in a pipeline static mixer; in the polymerization reaction, three layers of paddles are adopted for mixing, and the paddles are respectively a turbine paddle, a self-suction stirring paddle and an axial flow paddle from bottom to top. According to the method, continuous polymerization production of PAO is achieved, the requirement for large-scale production of PAO can be met, in addition, premixing and mixing are carried out through the pipeline static mixer and the blades of the specific structure respectively, the polymerization reaction efficiency is improved, the polymerization reaction is fully and stably carried out, the conversion efficiency of polymerization raw materials is improved, the PAO viscosity is reduced, and the production cost is reduced. The PAO product is narrow in molecular weight distribution and stable in quality.

Description

Technical Field

[0001] The invention relates to the technical field of poly-alpha-olefin production, and in particular to a continuous polymerization method and system of PAO. Background Art

[0002] The Chinese patent with publication number CN110627603A discloses a device and method for producing poly alpha-olefin (i.e. PAO) by a continuous process. The key components of this technology include a catalyst compounder, a multistage reactor, a catalyst metering pump and a chilled water unit. Among them, the multistage reactor is composed of a plurality of reactors connected in series, the first stage is a stirred tank reactor, and the rest can be stirred tank or tubular reactors. Each reactor is equipped with a cooling jacket or a built-in coil to achieve precise temperature control. However, this technology has certain limitations in catalyst preparation, that is, the catalyst is intermittently prepared rather than continuously prepared, which reduces the efficiency of industrial continuous production and is not conducive to industrial continuous production.

[0003] The Chinese patent with publication number CN110624487A discloses a poly-alpha-olefin reaction device and reaction method. The device includes a reactor and an external circulation heat removal system; the reactor includes a reactor body and a stirring device, and the stirring device includes a stirring shaft, a stirring paddle and a power mechanism; the external circulation heat removal system includes a jacket, a built-in coil, an external circulation pump, an external circulation cooler and a refrigerator, and the jacket and the built-in coil form an external circulation with the refrigerator to achieve precise control of the polymerization reaction temperature. This method can produce PAO base oil with stable and uniform quality. However, this technology adopts an intermittent production method, and the production efficiency is lower than that of a continuous production process, and may not meet the needs of large-scale production.

[0004] A Chinese patent with publication number CN218167040U discloses a polyalphaolefin lubricating oil reaction device. The device includes a reactor, a stirring mechanism, a heat exchange system and a heating system. The reactor is used for polymerization reaction; the stirring mechanism includes a stirring paddle arranged in the reactor cavity, which is used to stir the reaction materials; the heat exchange system includes a cooling coil and a refrigerator, the cooling coil is arranged around the stirring paddle, and is connected to the refrigerator, which is used to cool the fluid in the reactor cavity; the heating system includes a heating jacket and a heater, which is used to heat the reaction materials in the reactor cavity. This solution can solve the problem that the reaction temperature is difficult to control during the polymerization reaction in the prior art. However, this technology is for intermittent production of PAO. Compared with the continuous production process, the production efficiency of this patent cannot meet the requirements of large-scale production.

[0005] Therefore, it is necessary to design a large-scale continuous production technology for PAO to meet the requirements of large-scale production of PAO.

[0006] In addition, with the development of the global industrial and automotive industries, especially in the field of lubricating oils and greases, low-viscosity PAO has been widely used due to its excellent performance. However, the PAO products prepared by the existing process have uneven molecular weight distribution and unstable quality, which urgently need further improvement. Summary of the invention

[0007] The main purpose of the present invention is to provide a continuous polymerization method and system for PAO to solve the problems of low efficiency and unstable quality of PAO production process in the prior art.

[0008] In order to achieve the above-mentioned purpose, according to one aspect of the present invention, a continuous polymerization method of PAO is provided. The raw materials include a gas phase catalyst, an auxiliary agent and a polymerization raw material, the polymerization raw material includes an α-olefin of C8 to C12, and the polymerization raw material is divided into two parts, namely a first polymerization raw material and a second polymerization raw material. The continuous polymerization method of PAO includes the following steps: step S1, the gas phase catalyst, the auxiliary agent and the first polymerization raw material are mixed for the first time to obtain a first mixture; step S2, the first mixture is mixed for the second time to obtain a second mixture; step S3, the second mixture is mixed for the third time with the second polymerization raw material to perform a polymerization reaction to obtain PAO; wherein the second mixing is performed in a pipeline static mixer; the third mixing and polymerization reaction are performed in a polymerization kettle body equipped with three layers of blades, and the blades are respectively a turbine blade, a self-priming stirring blade, and an axial flow blade from bottom to top.

[0009] Furthermore, the gas phase catalyst includes boron trifluoride; and / or the auxiliary agent includes C2-C7 α-monoalcohol; and / or the content of 1-decene in the α-olefin of the polymerization raw material is ≥55% by weight.

[0010] Furthermore, in terms of weight percentage, the gas phase catalyst accounts for 2-7% of the raw material, preferably 2-5%; and / or the auxiliary agent accounts for 4-9% of the raw material; preferably, the weight ratio of the gas phase catalyst to the auxiliary agent is 1:(1-1.2); the weight ratio of the first polymerization raw material to the second polymerization raw material is 1:(8-10); and / or the first mixture contains a complex of the gas phase catalyst and the auxiliary agent, and the concentration of the complex is 0.3-0.9 mol / L.

[0011] Furthermore, the speed of the first mixing is 80 to 300 rpm, preferably 110 to 300 rpm; and / or the time of the first mixing is 1 to 10 min.

[0012] Furthermore, the second mixing time is 4 to 10 minutes.

[0013] Furthermore, the polymerization reaction temperature is 10-80°C, preferably 20-60°C; and / or the polymerization reaction time is 0.5-4h, preferably 1-3h; and / or the polymerization reaction pressure is 0.1-0.7MPa, preferably 0.2-0.5MPa; and / or the third mixing speed is 20-200rpm, preferably 80-200rpm.

[0014] Furthermore, the dynamic viscosity of PAO at 40°C is 2 to 15 mm 2 / s; and / or the condensation point of PAO is -20 to -40°C; and / or the conversion efficiency of the polymerization raw material is ≥85%; and / or the utilization rate of the gas phase catalyst is ≥88%.

[0015] According to another aspect of the present invention, a continuous polymerization system of PAO is provided. The raw materials include a gas phase catalyst, an auxiliary agent and a polymerization raw material, and the polymerization raw material includes α-olefins of C8 to C12. The polymerization raw material is divided into two parts, namely a first polymerization raw material and a second polymerization raw material. The continuous polymerization system of PAO includes: a stirring kettle, including: a stirring kettle body, having a first stirring feed inlet, a second stirring feed inlet, and a stirring discharge port; the gas phase catalyst enters the stirring kettle body from the first stirring feed inlet, and the auxiliary agent and the first polymerization raw material enter the stirring kettle body from the second stirring feed inlet; a first stirring paddle is arranged inside the stirring kettle body; a stirring kettle driving motor is connected to the first stirring paddle; a first cooling jacket is arranged around the outer wall of the stirring kettle body; the stirring kettle is used to perform a first mixing of the gas phase catalyst, the auxiliary agent and the first polymerization raw material to obtain a first mixture; a pipeline static mixer, including: a mixer body, having a static mixing feed inlet and a static mixing discharge port, and the static mixing feed inlet is connected to the stirring discharge port of the stirring kettle body. a second cooling jacket, which is arranged on the outer wall of the mixer body; a pipeline static mixer is used to perform a second mixing on the first mixture to obtain a second mixture; a polymerization reactor, comprising: a polymerization reactor body, having a first polymerization feed port, a second polymerization feed port, and a polymerization discharge port; the first polymerization feed port is connected to the static mixing discharge port of the mixer body; the second polymerization raw material enters the polymerization reactor body from the second polymerization feed port; a second stirring paddle, which is arranged inside the polymerization reactor body, and the second stirring paddle is a three-layer paddle structure, which are respectively a turbine paddle, a self-priming stirring paddle, and an axial flow paddle from bottom to top; a polymerization reactor drive motor, which is connected to the second stirring paddle; a coil, which is arranged inside the polymerization reactor body; a ring-shaped wire mesh, which is arranged on the inner wall of the polymerization reactor body; a third cooling jacket, which is arranged on the outer wall of the polymerization reactor body; the polymerization reactor is used to perform a third mixing on the second mixture and the second polymerization raw material to perform a polymerization reaction to obtain PAO.

[0016] Furthermore, in the polymerization reactor, the first polymerization feed inlet is located below the turbine propeller; and / or the second polymerization feed inlet is located above the self-priming stirring propeller; and / or the polymerization discharge port is located above the axial flow propeller.

[0017] Furthermore, chilled water is passed through the first cooling jacket, the second cooling jacket, the coil, and the third cooling jacket respectively and independently; preferably, the temperature of the chilled water is 3-12° C., and the flow rate is 0.5-2 m / s.

[0018] By applying the technical solution of the present invention, each raw material can be continuously added, and the product can be continuously taken out to realize the continuous polymerization production of PAO, which can meet the requirements of large-scale production of PAO. Moreover, in the method of the present invention, by premixing the gas phase catalyst, the auxiliary agent and part of the polymerization raw materials twice, one of which is premixed in a pipeline static mixer, and mixing with a specific structure blade, the activity and utilization rate of the gas phase catalyst can be effectively improved, and the uniformity of the material concentration and temperature distribution in each process can be effectively controlled, so as to promote the efficiency of the polymerization reaction, make the polymerization reaction fully and stably proceed, further help to improve the conversion efficiency of the polymerization raw materials, reduce the viscosity of PAO, and obtain a PAO product with a narrow molecular weight distribution and stable quality. BRIEF DESCRIPTION OF THE DRAWINGS

[0019] The drawings constituting a part of the present application are used to provide a further understanding of the present invention. The exemplary embodiments of the present invention and their descriptions are used to explain the present invention and do not constitute an improper limitation of the present invention. In the drawings:

[0020] Figure 1 A schematic diagram of a continuous polymerization system of PAO according to Example 1 of the present invention is shown;

[0021] The above drawings include the following reference numerals:

[0022] A, gas phase catalyst; B, auxiliary agent; C, first polymerization raw material; D, second polymerization raw material; E, PAO;

[0023] 1. stirring kettle; 11. stirring kettle body; 12. first stirring paddle; 13. stirring kettle driving motor; 14. first cooling jacket; 2. pipeline static mixer; 21. mixer body; 22. second cooling jacket; 3. polymerization reactor; 31. polymerization reactor body; 32. second stirring paddle; 321. turbine paddle; 322. self-priming stirring paddle; 323. axial flow paddle; 33. polymerization reactor driving motor; 34. coil; 35. annular wire mesh; 36. third cooling jacket. DETAILED DESCRIPTION

[0024] It should be noted that, in the absence of conflict, the embodiments and features in the embodiments of the present application can be combined with each other. The present invention will be described in detail below with reference to the accompanying drawings and in combination with the embodiments.

[0025] Terminology explanation:

[0026] Catalyst utilization: (actual reaction rate / theoretical maximum reaction rate)×100%.

[0027] Dynamic viscosity: also known as absolute viscosity or internal friction coefficient, is a physical quantity that describes the internal resistance of a fluid (liquid or gas). It represents the friction between adjacent layers when the fluid flows.

[0028] As described in the background of the present invention, there are problems in the prior art of PAO production process with low efficiency and unstable quality. In order to solve the above problems, in a typical embodiment of the present invention, a continuous polymerization method of PAO is provided, the raw materials include a gas phase catalyst, an auxiliary agent and a polymerization raw material, the polymerization raw material includes C8 to C12 α-olefins, the polymerization raw material is divided into two parts, namely a first polymerization raw material and a second polymerization raw material, and the continuous polymerization method of PAO includes the following steps: step S1, the gas phase catalyst, the auxiliary agent and the first polymerization raw material are mixed for the first time to obtain a first mixture; step S2, the first mixture is mixed for the second time to obtain a second mixture; step S3, the second mixture is mixed for the third time with the second polymerization raw material to perform a polymerization reaction to obtain PAO; wherein the second mixing is performed in a pipeline static mixer; the third mixing and polymerization reaction are performed using a polymerization kettle body equipped with three layers of blades, and the blades are respectively a turbine blade, a self-priming stirring blade, and an axial flow blade from bottom to top.

[0029] The present application particularly adopts a gas phase catalyst for the continuous polymerization of PAO. The gas phase catalyst has high activity and high selectivity, can achieve a high conversion rate at a relatively low temperature and pressure, improve production efficiency, and can effectively control the molecular weight distribution and structure of the product PAO. It is also easy to separate, which helps to improve the recycling rate of the catalyst and reduce production costs during the continuous polymerization process. There are fewer side reactions, which is beneficial to improve the purity of PAO.

[0030] In the continuous polymerization method of PAO of the present application, the gas-phase catalyst, the auxiliary agent and part of the polymerization raw materials are first premixed. On the one hand, the catalyst, the auxiliary agent and part of the polymerization raw materials can be preliminarily mixed, so that the catalyst and the auxiliary agent can complete the complexation to obtain a mixture containing a gas-phase catalyst and an auxiliary agent complex, and form an active site. The complex is beneficial to improving the activity and utilization rate of the gas-phase catalyst, enhancing the selectivity of the polymerization reaction, and further facilitating the full progress of the subsequent polymerization reaction; on the other hand, premixing can enhance the mass transfer effect of the gas-phase catalyst in the liquid phase, improve the utilization rate of the gas-phase catalyst, and improve the stability of the gas-phase catalyst and the auxiliary agent during the polymerization process, thereby helping to improve the efficiency of the polymerization reaction and the conversion efficiency of the polymerization raw materials, and improve the quality of the PAO product.

[0031] Next, the generated first mixture is subjected to a second mixing in a pipeline static mixer. In this process, the gas phase catalyst can be further dispersed, so that the gas phase catalyst, the auxiliary agent and the polymerization raw material are efficiently mixed and fully dispersed, and the polymerization of the gas phase catalyst is effectively inhibited, thereby facilitating the improvement of the rate and catalytic effect of the subsequent polymerization reaction, and the quality of the PAO product. In addition, the pipeline static mixer is small in size, occupies less space, has low energy consumption and low maintenance cost.

[0032] Finally, the second mixture is mixed with part of the polymerization raw materials to cause a polymerization reaction. Since the gas phase catalyst is fully dispersed in the previous process, the temperature of each material can be effectively controlled and the temperature distribution is uniform in the third mixing process. The gas phase catalyst has high activity and high utilization rate, so that the polymerization reaction can be carried out continuously and stably, and a PAO product with narrow molecular weight distribution and stable quality is obtained.

[0033] It should be noted that the present application specifically adopts a three-layer blade structure for the third mixing, and the blades are respectively a turbine blade, a self-priming stirring blade, and an axial flow blade from bottom to top. Among them, the turbine blade on the bottom layer can effectively disperse the gas-liquid mixture containing the gas-phase catalyst, thereby improving the uniformity of the material; the self-priming blade on the middle layer can re-absorb the gas-phase catalyst that escapes from the surface of the liquid phase in the reactor without complexation into the liquid phase, thereby improving the utilization rate of the gas-phase catalyst; the axial flow blade on the top layer can form an axial overall circulation flow field in the reactor, thereby enhancing the mixing effect in the reactor. Preferably, the axial flow blade adopts a downward pressure operation to prevent the bubbles formed by the gas-phase catalyst from short-circuiting in the liquid phase and escaping from the liquid phase prematurely, thereby further improving the utilization rate of the catalyst.

[0034] In summary, in the method of the present application, each raw material can be added continuously, and the product can be taken out continuously to realize the continuous polymerization production of PAO, which can meet the requirements of large-scale production of PAO. Moreover, in the method of the present application, by premixing the gas phase catalyst, the auxiliary agent and part of the polymerization raw materials twice, one of which is premixed in a pipeline static mixer, and mixing with a specific structure blade, the activity and utilization rate of the gas phase catalyst can be effectively improved, and the uniformity of the material concentration and temperature distribution in each process can be effectively controlled, so as to promote the efficiency of the polymerization reaction, make the polymerization fully and stably, and further help to improve the conversion efficiency of the polymerization raw materials, reduce the viscosity of PAO, and obtain a PAO product with a narrow molecular weight distribution and stable quality.

[0035] The polymerization method of the present application is applicable to conventional types of gas phase catalysts, auxiliary agents and polymerization raw materials in the art. In a preferred embodiment, the gas phase catalyst includes boron trifluoride; and / or the auxiliary agent includes C2-C7 α-monoalcohol, preferably one or more of n-hexanol, n-pentanol, n-heptanol and n-octanol; and / or the polymerization raw material includes C8-C12 α-olefins; preferably, in terms of weight percentage, the content of 1-decene in the α-olefin is ≥55%, more preferably 55-70%. Under the above conditions, the synergistic effect between the raw materials is better, which is more conducive to increasing the rate of the polymerization reaction, and making the molecular weight distribution of the PAO product more uniform, the viscosity and pour point lower, and the quality more stable.

[0036] In the polymerization process, the content of gas phase catalyst and auxiliary agent has an important influence on the efficiency of the polymerization reaction and the quality of the product. In a preferred embodiment, the gas phase catalyst accounts for 2-7% of the raw material by weight percentage, preferably 2-5%. If the gas catalyst content is lower than this range, the concentration of the catalyst complex in the liquid phase may be too low, which may easily lead to a lower polymerization reaction rate and production efficiency; if the gas catalyst content is higher than this range, it may cause a waste of raw materials and reduce the economic efficiency of the production process.

[0037] In a preferred embodiment, the auxiliary agent accounts for 4-9% of the raw material by weight percentage; preferably, the weight ratio of the gas phase catalyst to the auxiliary agent is 1: (1-1.2); and / or the first mixture contains a complex of the gas phase catalyst and the auxiliary agent, and the concentration of the complex is 0.3-0.9 mol / L. Under the above conditions, the gas phase catalyst and the auxiliary agent can cooperate more fully, the utilization rate of the catalyst is higher, the rate of the polymerization reaction is more suitable, and the molecular weight distribution of the prepared PAO is narrower.

[0038] In order to further effectively control the polymerization reaction temperature and rate, in a preferred embodiment, the weight ratio of the first polymerization raw material to the second polymerization raw material is 1: (8-10). It should be noted that the components of the two parts of the polymerization raw materials are the same. If the weight ratio is greater than 1:8, the first polymerization raw material accounts for a relatively large proportion, and the investment in the equipment used in the premixing process increases. If the weight ratio is less than 1:10, the first polymerization raw material accounts for a relatively small proportion, and the catalyst content in the premixing process is relatively high, which may cause the local temperature to be too high and the polymerization speed to be too fast during the first mixing process, thereby affecting the quality of the final product.

[0039] In order to make the distribution of the gas phase catalyst, the auxiliary agent and the first polymerization raw material more uniform and improve the mass transfer effect of the gas phase catalyst in the liquid phase, the speed of the first mixing is 80 to 300 rpm, preferably 110 to 300 rpm; and / or the time of the first mixing is 1 to 10 minutes. If the stirring speed is lower than this range, the gas-liquid mass transfer efficiency in the reactor may be reduced, affecting the utilization efficiency of the gas phase catalyst; if the stirring speed is higher than this range, the gas-liquid dispersion mixing effect may not be significantly improved, and the power consumption continues to increase, which is not conducive to energy saving and consumption reduction.

[0040] In a preferred embodiment, the second mixing time is 4 to 10 minutes; and / or the model of the pipeline static mixer includes one or more of SX, SL and SV. Under the above conditions, the gas phase catalyst, the auxiliary agent and the first polymerization raw material are mixed more uniformly, which can further inhibit the polymerization of the gas phase catalyst.

[0041] In order to further improve the polymerization reaction rate, in a preferred embodiment, the polymerization reaction temperature is 10 to 80° C., preferably 20 to 60° C. If the reaction temperature is lower than this range, the polymerization reaction rate is too low, which may make it difficult to achieve the target yield of the reaction system; if the reaction temperature is higher than this range, the polymerization reaction rate is too fast, which may easily cause phenomena such as temperature runaway and implosion in the reactor, and the system cannot run continuously and stably, affecting production efficiency.

[0042] In a preferred embodiment, the polymerization reaction time is 0.5 to 4 hours, preferably 1 to 3 hours. If the reaction time is too long, it may lead to reduced production efficiency and excessive equipment investment. If the reaction time is too short, it may lead to insufficient raw material conversion rate.

[0043] In order to further improve the solubility of the gas phase catalyst and further increase the polymerization reaction rate, in a preferred embodiment, the polymerization reaction pressure is 0.1-0.7 MPa, preferably 0.2-0.5 MPa. If the reaction pressure is too low, the solubility of the gas phase catalyst in the liquid phase is low, and the driving force of gas-liquid mass transfer is low, which easily leads to a low polymerization reaction rate; if the reaction pressure is higher than this range, the solubility of the gas phase catalyst cannot be effectively improved, which may lead to too low polymerization efficiency, and the reactor manufacturing cost will continue to increase, and the system economy will be reduced.

[0044] In a preferred embodiment, the speed of the third mixing is 20 to 200 rpm, preferably 80 to 200 rpm. When the stirring speed is lower than this range, the concentration and temperature distribution may be uneven, thereby affecting the molecular weight distribution of the product; when the stirring speed is higher than this range, there is no obvious improvement in the mixing effect in the reactor, and the power consumption continues to increase, which does not meet the requirements of energy saving and consumption reduction.

[0045] In a preferred embodiment, the dynamic viscosity of PAO at 40°C is 2 to 15 mm 2 / s; and / or the freezing point of PAO is -20 to -40°C; and / or the conversion efficiency of the polymerization raw material is ≥85%; and / or the utilization rate of the gas phase catalyst is ≥88%. The continuous polymerization method of the present application can more efficiently, stably and continuously prepare a low-freezing point and low-viscosity PAO product, and the conversion efficiency of the polymerization raw material is high and the utilization rate of the catalyst is high.

[0046] In another typical embodiment of the present invention, a continuous polymerization system of PAO is also provided, wherein the raw materials include a gas-phase catalyst, an auxiliary agent and a polymerization raw material, the polymerization raw material includes an α-olefin of C8 to C12, and the polymerization raw material is divided into two parts, namely a first polymerization raw material and a second polymerization raw material. The continuous polymerization system of PAO includes: a stirred tank 1, including: a stirred tank body 11, having a first stirring feed port, a second stirring feed port, and a stirring discharge port; the gas-phase catalyst enters the stirred tank body 11 from the first stirring feed port, and the auxiliary agent and the first polymerization raw material enter the stirred tank body 11 from the second stirring feed port; a first stirring paddle 12 is arranged inside the stirred tank body 11; a stirring tank drive motor 13 is connected to the first stirring paddle 12; a first cooling jacket 14 is arranged around the outer wall of the stirring tank body 11; the stirred tank 1 is used to perform a first mixing of the gas-phase catalyst, the auxiliary agent and the first polymerization raw material to obtain a first mixture; a pipeline static mixer 2, including: a mixer body 21, having a static mixing feed port and a static mixing discharge port, and the static mixing feed port is connected to the stirring tank body 1 1 is connected to the stirring outlet of the mixer body 21; the second cooling jacket 22 is arranged around the outer wall of the mixer body 21; the pipeline static mixer 2 is used to perform a second mixing on the first mixture to obtain a second mixture; the polymerization reactor 3 includes: a polymerization reactor body 31, having a first polymerization feed port, a second polymerization feed port, and a polymerization outlet; the first polymerization feed port is connected to the static mixing outlet of the mixer body 21; the second polymerization raw material enters the polymerization reactor body 31 from the second polymerization feed port; the second stirring paddle 32 is arranged inside the polymerization reactor body 31 The second stirring paddle 32 is a three-layer paddle structure, which includes a turbine paddle 321, a self-priming stirring paddle 322, and an axial flow paddle 323 from bottom to top; the polymerization reactor driving motor 33 is connected to the second stirring paddle 32; the coil 34 is arranged inside the polymerization reactor body 31; the annular wire mesh 35 is arranged on the inner wall of the polymerization reactor body 31; the third cooling jacket 36 is arranged on the outer wall of the polymerization reactor body 31; the polymerization reactor 3 is used to perform a third mixing of the second mixture and the second polymerization raw material to perform a polymerization reaction to obtain PAO.

[0047] First, the gas phase catalyst enters the stirring tank body through the first stirring feed port of the stirring tank body 11, and the auxiliary agent and part of the polymerization raw materials enter the stirring tank body through the second stirring feed port of the stirring tank body 11. Driven by the stirring tank driving motor 13, the first stirring paddle 12 rotates to premix the gas phase catalyst, auxiliary agent and part of the polymerization raw materials. A first cooling jacket 14 is arranged on the outer wall of the stirring tank body 11 to take away the heat generated by the complexation reaction of the gas phase catalyst in time. In the stirring tank 1, on the one hand, the catalyst, auxiliary agent and part of the polymerization raw materials can be preliminarily mixed, so that the catalyst and auxiliary agent complete the complexation to obtain a mixture containing a gas phase catalyst and auxiliary agent complex, and form an active site. The complex is conducive to improving the activity and utilization rate of the gas phase catalyst, improving the selectivity of the polymerization reaction, and then facilitating the full progress of the subsequent polymerization reaction; on the other hand, premixing can enhance the mass transfer effect of the gas phase catalyst in the liquid phase, improve the utilization rate of the gas phase catalyst, and improve the stability of the gas phase catalyst and auxiliary agent during the polymerization process, thereby helping to improve the efficiency of the polymerization reaction and the conversion efficiency of the polymerization raw materials, and improve the quality of the PAO product.

[0048] Next, the generated first mixture passes through the stirring discharge port of the stirring kettle body 11 and the static mixing feed port of the mixer body 21, and enters the mixer body 21 of the pipeline static mixer for second mixing. A second cooling jacket 22 is provided on the outer wall of the mixer body 21, which can effectively control the temperature of the material in the pipeline. In the pipeline static mixer 2, the gas phase catalyst can be further dispersed, so that the gas phase catalyst, auxiliary agent and polymerization raw materials are efficiently mixed and fully dispersed, and the aggregation of the gas phase catalyst is effectively suppressed, which is beneficial to improve the rate and catalytic effect of the subsequent polymerization reaction, and is beneficial to improve the quality of the PAO product. Moreover, the pipeline static mixer is small in size, occupies less space, has low energy consumption and low maintenance cost.

[0049] Finally, the second mixture passes through the static mixing outlet of the mixer body 21 and the first polymerization feed port of the polymerization kettle body 31, and enters the polymerization kettle body 31. The second polymerization raw material enters the polymerization kettle body 31 from the second polymerization feed port. Driven by the polymerization reactor driving motor 33, the second stirring paddle 32 rotates to mix the second mixture with part of the polymerization raw material and cause polymerization reaction. A coil 34 is arranged inside the polymerization kettle body 31, and a third cooling jacket 36 is arranged on the outer wall, which can take away the heat in the polymerization reaction process in time, which is conducive to the continuous and stable polymerization reaction. In addition, an annular wire mesh 35 is arranged on the inner wall of the polymerization kettle body 31, which can enhance the bubble crushing effect and improve the utilization rate of the gas phase catalyst. Since the gas phase catalyst is fully dispersed in the early stage, in the third mixing process, the temperature of each material can be effectively controlled and the temperature distribution is uniform, the gas phase catalyst is highly active and has a high utilization rate, so that the polymerization reaction can be carried out continuously and stably, and a PAO product with a narrow molecular weight distribution and stable quality is obtained.

[0050] It should be noted that the second stirring paddle 32 in the present application is a three-layer blade structure, and the blades are respectively a turbine paddle, a self-priming stirring paddle, and an axial flow paddle from bottom to top. Among them, the turbine paddle at the bottom layer can effectively disperse the gas-liquid mixture containing the gas-phase catalyst, thereby improving the uniformity of the material; the self-priming paddle at the middle layer can re-absorb the gas-phase catalyst that escapes from the surface of the liquid phase in the reactor without complexation into the liquid phase, thereby improving the utilization rate of the gas-phase catalyst; the axial flow paddle at the top layer can form an axial overall circulating flow field in the reactor, thereby enhancing the mixing effect in the reactor. Preferably, the axial flow paddle adopts a downward pressure operation to prevent the bubbles formed by the gas-phase catalyst from short-circuiting in the liquid phase and escaping from the liquid phase prematurely, thereby further improving the utilization rate of the catalyst.

[0051] In summary, in the device of the present application, each raw material can be added continuously, and the product can be taken out continuously to realize the continuous polymerization production of PAO, which can meet the requirements of large-scale production of PAO. Moreover, in the device of the present application, by premixing the gas phase catalyst, the auxiliary agent and part of the polymerization raw materials twice, one of which is premixed in a pipeline static mixer, and mixing with a specific structure blade, the activity and utilization rate of the gas phase catalyst can be effectively improved, and the uniformity of the material concentration and temperature distribution in each process can be effectively controlled, so as to promote the efficiency of the polymerization reaction, make the polymerization fully and stably, and further help to improve the conversion efficiency of the polymerization raw materials, reduce the viscosity of PAO, and obtain a PAO product with a narrow molecular weight distribution and stable quality.

[0052] In a preferred embodiment, in the polymerization reactor 3, the first polymerization feed port is located below the turbine impeller; and / or the second polymerization feed port is located above the self-priming stirring impeller; and / or the polymerization discharge port is located above the axial flow impeller. Under the above conditions, the concentration of each material and the heat distribution are more uniform.

[0053] In a preferred embodiment, chilled water is passed through the first cooling jacket 14, the second cooling jacket 22, the coil 34, and the third cooling jacket 36, respectively; preferably, the temperature of the chilled water is 3 to 12°C, and the flow rate is 0.5 to 2 m / s. Under the above conditions, the heat generated by the reaction can be taken away more promptly, the temperature stability in the equipment can be maintained, and the polymerization reaction can be carried out more stably and fully. It should be noted that the above-mentioned chilled water can be the commonly used chilled water in the technical field, which will not be repeated here.

[0054] The present application is further described in detail below in conjunction with specific embodiments. These embodiments should not be construed as limiting the scope of protection claimed in the present application.

[0055] Example 1

[0056] The schematic diagram of the continuous polymerization system of PAO is shown in Figure 1 .

[0057] The continuous polymerization system of PAO comprises a stirring kettle 1, a pipeline static mixer 2, and a polymerization reactor 3.

[0058] Among them, the stirring tank 1 includes: a stirring tank body 11, having a first stirring feed port, a second stirring feed port, and a stirring discharge port; a first stirring paddle 12, arranged inside the stirring tank body 11; a stirring tank drive motor 13, connected to the first stirring paddle 12; a first cooling jacket 14, with chilled water flowing inside, the flow rate of the cooling water is 1.2m / s, the temperature is 5°C, and it is surrounded by the outer wall of the stirring tank body 11.

[0059] The pipeline static mixer 2 (model SX) includes: a mixer body 21, having a static mixing feed port and a static mixing discharge port, the static mixing feed port is connected to the stirring discharge port of the stirring kettle body 11; a second cooling jacket 22, with chilled water flowing inside, the flow rate of the cooling water is 1.5m / s, the temperature is 5°C, and is surrounded by the outer wall of the mixer body 21.

[0060] The polymerization reactor 3 comprises: a polymerization reactor body 31, having a first polymerization feed port, a second polymerization feed port, and a polymerization discharge port, wherein the first polymerization feed port is connected to the static mixing discharge port of the mixer body 21, and the second polymerization raw material enters the polymerization reactor body 31 from the second polymerization feed port; a second stirring paddle 32, wherein the second stirring paddle 32 is a three-layer paddle structure, which comprises a turbine paddle 321, a self-priming stirring paddle 322, and an axial flow paddle 323 from bottom to top; a polymerization reactor driving motor 33, which is connected to the second stirring paddle 32; a disk Pipe 34, inside of which chilled water flows, the flow rate of cooling water is 1.1m / s, and the temperature is 5°C, is arranged inside the polymerization kettle body 31; annular wire mesh 35 is arranged on the inner wall of the polymerization kettle body 31; a third cooling jacket 36, inside of which chilled water flows, the flow rate of cooling water is 1.3m / s, and the temperature is 5°C, is arranged on the outer wall of the polymerization kettle body 31; the first polymerization feed port is located below the turbine impeller; the second polymerization feed port is located above the self-priming stirring impeller; the polymerization discharge port is located above the axial flow impeller.

[0061] The raw materials of PAO E include gas phase catalyst A (boron trifluoride), auxiliary agent B (n-hexanol) and polymerization raw material (including 70wt% of 1-decene and 30wt% of C9-C11 alkane). The polymerization raw material is divided into two parts, namely a first polymerization raw material C and a second polymerization raw material D, wherein, by weight percentage, the gas phase catalyst accounts for 4.5%, the auxiliary agent accounts for 5%, the first polymerization raw material accounts for 10%, and the second polymerization raw material accounts for 80.5%.

[0062] Step S1, the gas phase catalyst enters the stirring tank body through the first stirring feed port of the stirring tank body 11, and the auxiliary agent and part of the polymerization raw material enter the stirring tank body through the second stirring feed port of the stirring tank body 11. Driven by the stirring tank driving motor 13, the first stirring paddle 12 rotates at a speed of 120 rpm, and the gas phase catalyst, auxiliary agent and part of the polymerization raw material are first mixed. After staying for 5 minutes, a first mixture of a complex containing the gas phase catalyst and the auxiliary agent is obtained, wherein the concentration of the complex is 0.52 mol / L.

[0063] Step S2, passing the generated first mixture through the stirring discharge port of the stirring kettle body 11 and the static mixing feed port of the mixer body 21, and entering the mixer body 21 of the pipeline static mixer for second mixing. After staying for 6 minutes, a second mixture is obtained.

[0064] Step S3, the second mixture passes through the static mixing outlet of the mixer body 21 and the first polymerization feed port of the polymerization kettle body 31, and enters the polymerization kettle body 31. The second polymerization raw material enters the polymerization kettle body 31 from the second polymerization feed port. Driven by the polymerization reactor drive motor 33, the second stirring paddle 32 rotates at a speed of 130 rpm, so that the second mixture is mixed with part of the polymerization raw material, and a polymerization reaction occurs. The polymerization reaction temperature is 35°C, the pressure is 0.3 MPa, and the time is 150 min to obtain PAO.

[0065] Example 2

[0066] The only difference from Example 1 is that the raw material of PAO is different.

[0067] The raw materials of PAO include gas phase catalyst (BF 3 ), an auxiliary agent (n-hexanol) and a polymerization raw material (including 60wt% of 1-decene and 40wt% of C9-C11 alkane), the polymerization raw material is divided into two parts, namely a first polymerization raw material and a second polymerization raw material, wherein, by weight percentage, the gas phase catalyst accounts for 3.5%, the auxiliary agent accounts for 4%, the first polymerization raw material accounts for 9%, and the second polymerization raw material accounts for 83.5%. The first mixture contains a complex of the gas phase catalyst and the auxiliary agent, and the concentration of the complex is 0.42mol / L.

[0068] Example 3

[0069] The only difference from Example 1 is that the raw material of PAO is different.

[0070] The raw materials of PAO include gas phase catalyst (BF 3), an auxiliary agent (n-pentanol) and a polymerization raw material (including 55wt% of 1-decene and 45wt% of C9-C11 alkane), the polymerization raw material is divided into two parts, namely a first polymerization raw material and a second polymerization raw material, wherein, by weight percentage, the gas phase catalyst accounts for 5%, the auxiliary agent accounts for 5%, the first polymerization raw material accounts for 10%, and the second polymerization raw material accounts for 80%. The first mixture contains a complex of the gas phase catalyst and the auxiliary agent, and the concentration of the complex is 0.52mol / L.

[0071] Example 4

[0072] The only difference from Example 1 is that the raw material of PAO is different.

[0073] The raw materials of PAO include gas phase catalyst (BF 3 ), an auxiliary agent (n-pentanol) and a polymerization raw material (including 55wt% of 1-decene and 45wt% of C9-C11 alkane), the polymerization raw material is divided into two parts, namely a first polymerization raw material and a second polymerization raw material, wherein, by weight percentage, the gas phase catalyst accounts for 2%, the auxiliary agent accounts for 4%, the first polymerization raw material accounts for 10%, and the second polymerization raw material accounts for 84%. The first mixture contains a complex of the gas phase catalyst and the auxiliary agent, and the concentration of the complex is 0.32mol / L.

[0074] Example 5

[0075] The only difference from Example 1 is that the raw material of PAO is different.

[0076] The raw materials of PAO include gas phase catalyst (BF 3 ), an auxiliary agent (n-pentanol) and a polymerization raw material (including 55wt% of 1-decene and 45wt% of C9-C11 alkane), the polymerization raw material is divided into two parts, namely a first polymerization raw material and a second polymerization raw material, wherein, by weight percentage, the gas phase catalyst accounts for 7%, the auxiliary agent accounts for 8.4%, the first polymerization raw material accounts for 7.7%, and the second polymerization raw material accounts for 76.9%. The first mixture contains a complex of the gas phase catalyst and the auxiliary agent, and the concentration of the complex is 0.82mol / L.

[0077] Example 6

[0078] The only difference from Example 1 is that the process parameters are different.

[0079] Step S1, the gas phase catalyst enters the stirring tank body through the first stirring feed port of the stirring tank body 11, and the auxiliary agent and part of the polymerization raw material enter the stirring tank body through the second stirring feed port of the stirring tank body 11. Driven by the stirring tank driving motor 13, the first stirring paddle 12 rotates at a speed of 80 rpm, and the gas phase catalyst, auxiliary agent and part of the polymerization raw material are first mixed. After mixing for 10 minutes, a first mixture of a complex containing the gas phase catalyst and the auxiliary agent is obtained, wherein the concentration of the complex is 0.52 mol / L.

[0080] Step S2, passing the generated first mixture through the stirring discharge port of the stirring kettle body 11 and the static mixing feed port of the mixer body 21, and entering the mixer body 21 of the pipeline static mixer for second mixing. After staying for 4 minutes, a second mixture is obtained.

[0081] Step S3, the second mixture passes through the static mixing outlet of the mixer body 21 and the first polymerization feed port of the polymerization kettle body 31, and enters the polymerization kettle body 31. The second polymerization raw material enters the polymerization kettle body 31 from the second polymerization feed port. Driven by the polymerization reactor drive motor 33, the second stirring paddle 32 rotates at a speed of 20 rpm, so that the second mixture is mixed with part of the polymerization raw material, and a polymerization reaction occurs. The polymerization reaction temperature is 10°C, the pressure is 0.1 MPa, and the time is 240 min to obtain PAO.

[0082] Example 7

[0083] The only difference from Example 1 is that the process parameters are different.

[0084] Step S1, the gas phase catalyst enters the stirring tank body through the first stirring feed port of the stirring tank body 11, and the auxiliary agent and part of the polymerization raw material enter the stirring tank body through the second stirring feed port of the stirring tank body 11. Driven by the stirring tank driving motor 13, the first stirring paddle 12 rotates at a speed of 300 rpm, and the gas phase catalyst, the auxiliary agent and part of the polymerization raw material are first mixed. After mixing for 1 minute, a first mixture of a complex containing the gas phase catalyst and the auxiliary agent is obtained, wherein the concentration of the complex is 0.46 mol / L.

[0085] Step S2, passing the generated first mixture through the stirring discharge port of the stirring kettle body 11 and the static mixing feed port of the mixer body 21, and entering the mixer body 21 of the pipeline static mixer for second mixing. After staying for 10 minutes, a second mixture is obtained.

[0086] Step S3, the second mixture passes through the static mixing outlet of the mixer body 21 and the first polymerization feed port of the polymerization kettle body 31, and enters the polymerization kettle body 31. The second polymerization raw material enters the polymerization kettle body 31 from the second polymerization feed port. Driven by the polymerization reactor drive motor 33, the second stirring paddle 32 rotates at a speed of 200 rpm, so that the second mixture is mixed with part of the polymerization raw material, and a polymerization reaction occurs. The polymerization reaction temperature is 80°C, the pressure is 0.7 MPa, and the time is 30 min to obtain PAO.

[0087] Example 8

[0088] The only difference from Example 1 is that the process parameters are different.

[0089] Step S1, the gas phase catalyst enters the stirring tank body through the first stirring feed port of the stirring tank body 11, and the auxiliary agent and part of the polymerization raw material enter the stirring tank body through the second stirring feed port of the stirring tank body 11. Driven by the stirring tank driving motor 13, the first stirring paddle 12 rotates at a speed of 110 rpm, and the gas phase catalyst, the auxiliary agent and part of the polymerization raw material are first mixed. After mixing for 10 minutes, a first mixture of a complex containing the gas phase catalyst and the auxiliary agent is obtained, wherein the concentration of the complex is 0.35 mol / L.

[0090] Step S2, passing the generated first mixture through the stirring discharge port of the stirring kettle body 11 and the static mixing feed port of the mixer body 21, and entering the mixer body 21 of the pipeline static mixer for second mixing. After staying for 4 minutes, a second mixture is obtained.

[0091] Step S3, the second mixture passes through the static mixing outlet of the mixer body 21 and the first polymerization feed port of the polymerization kettle body 31, and enters the polymerization kettle body 31. The second polymerization raw material enters the polymerization kettle body 31 from the second polymerization feed port. Driven by the polymerization reactor drive motor 33, the second stirring paddle 32 rotates at a speed of 80 rpm, so that the second mixture is mixed with part of the polymerization raw material, and a polymerization reaction occurs. The polymerization reaction temperature is 20°C, the pressure is 0.2 MPa, and the time is 180 min to obtain PAO.

[0092] Example 9

[0093] The only difference from Example 1 is that the process parameters are different.

[0094] Step S1, the gas phase catalyst enters the stirring tank body through the first stirring feed port of the stirring tank body 11, and the auxiliary agent and part of the polymerization raw material enter the stirring tank body through the second stirring feed port of the stirring tank body 11. Driven by the stirring tank driving motor 13, the first stirring paddle 12 rotates at a speed of 300 rpm, and the gas phase catalyst, the auxiliary agent and part of the polymerization raw material are first mixed. After mixing for 1 minute, a first mixture of a complex containing the gas phase catalyst and the auxiliary agent is obtained, wherein the concentration of the complex is 0.32 mol / L.

[0095] Step S2, passing the generated first mixture through the stirring discharge port of the stirring kettle body 11 and the static mixing feed port of the mixer body 21, and entering the mixer body 21 of the pipeline static mixer for second mixing. After staying for 10 minutes, a second mixture is obtained.

[0096] Step S3, the second mixture passes through the static mixing outlet of the mixer body 21 and the first polymerization feed port of the polymerization kettle body 31, and enters the polymerization kettle body 31. The second polymerization raw material enters the polymerization kettle body 31 from the second polymerization feed port. Driven by the polymerization reactor drive motor 33, the second stirring paddle 32 rotates at a speed of 200 rpm, so that the second mixture is mixed with part of the polymerization raw material, and a polymerization reaction occurs. The polymerization reaction temperature is 60°C, the pressure is 0.5 MPa, and the time is 60 min to obtain PAO.

[0097] Comparative Example 1

[0098] The only difference from Example 1 is that the second mixing is carried out in a single-layer turbine propeller stirred tank.

[0099] Comparative Example 2

[0100] The only difference from Example 1 is that a single-layer turbine propeller is used for the third mixing.

[0101] The test results of conversion efficiency, catalyst utilization, dynamic viscosity and freezing point of the polymer raw materials of PAO prepared in the above examples and comparative examples are shown in Table 1.

[0102] Test method:

[0103] Conversion efficiency of polymer raw materials: tested by liquid chromatography;

[0104] Catalyst utilization rate: tested by gas chromatograph;

[0105] Dynamic viscosity: tested under the conditions of GBT1995-88;

[0106] Solidification point: tested under the conditions of GBT510-83.

[0107] Table 1

[0108]

[0109]

[0110] As can be seen from the above, by adopting the technical solution of the present invention, each raw material can be continuously added, and the product can be continuously taken out, so that the continuous polymerization production of PAO can be realized, and the requirements for large-scale production of PAO can be met. Moreover, in the method of the present invention, by premixing the gas phase catalyst, the auxiliary agent and part of the polymerization raw materials twice, one of which is premixed in a pipeline static mixer, and mixing with a specific structure blade, the activity and utilization rate of the gas phase catalyst are effectively improved, the uniformity of the material concentration and temperature distribution in each process is controlled, the efficiency of the polymerization reaction is promoted, the polymerization reaction can be fully and stably carried out, the conversion efficiency of the polymerization raw materials is further improved, the viscosity of PAO is reduced, and a PAO product with a low freezing point, a narrow molecular weight distribution and stable quality is obtained.

[0111] In addition, it can be seen that when the process parameters are within the preferred range of the present invention, the viscosity of PAO is lower, the freezing point is lower, the molecular weight distribution is narrower, and the quality is more stable.

[0112] The above description is only a preferred embodiment of the present invention and is not intended to limit the present invention. For those skilled in the art, the present invention may have various modifications and variations. Any modification, equivalent replacement, improvement, etc. made within the spirit and principle of the present invention shall be included in the protection scope of the present invention.

Claims

1. A continuous polymerization method of PAO, characterized in that: The raw materials include a gas phase catalyst, an auxiliary agent and a polymerization raw material, wherein the polymerization raw material includes C8 to C12 α-olefins, and the polymerization raw material is divided into two parts, namely a first polymerization raw material and a second polymerization raw material. The continuous polymerization method of PAO includes the following steps: Step S1, mixing the gas phase catalyst, the auxiliary agent and the first polymerization raw material to obtain a first mixture; Step S2, performing a second mixing on the first mixture to obtain a second mixture; Step S3, performing a third mixing of the second mixture and the second polymerization raw material to perform a polymerization reaction to obtain the PAO; Wherein, the second mixing is carried out in a pipeline static mixer; the third mixing and the polymerization reaction are carried out in a polymerization kettle body equipped with three layers of blades, and the blades are respectively a turbine blade, a self-priming stirring blade, and an axial flow blade from bottom to top.

2. The continuous polymerization method according to claim 1, characterized in that The gas phase catalyst comprises boron trifluoride; and / or The auxiliary agent includes C2-C7 α-monoalcohol; and / or Calculated by weight percentage, the content of 1-decene in the α-olefin of the polymerization raw material is ≥55%.

3. The continuous polymerization method according to claim 1 or 2, characterized in that Calculated by weight percentage, The gas phase catalyst accounts for 2-7% of the raw material, preferably 2-5%; and / or The auxiliary agent accounts for 4 to 9% of the raw material; Preferably, the weight ratio of the gas phase catalyst to the auxiliary agent is 1:(1-1.2); The weight ratio of the first polymer raw material to the second polymer raw material is 1:(8-10); and / or The first mixture contains a complex of the gas-phase catalyst and the auxiliary agent, and the concentration of the complex is 0.3-0.9 mol / L.

4. The continuous polymerization method according to any one of claims 1 to 3, characterized in that The first mixing speed is 80 to 300 rpm, preferably 110 to 300 rpm; and / or The first mixing time is 1 to 10 minutes.

5. The continuous polymerization method according to any one of claims 1 to 4, characterized in that The second mixing time is 4 to 10 minutes.

6. The continuous polymerization method according to any one of claims 1 to 5, characterized in that The polymerization reaction temperature is 10 to 80° C., preferably 20 to 60° C.; and / or The polymerization reaction time is 0.5 to 4 hours, preferably 1 to 3 hours; and / or The polymerization reaction pressure is 0.1-0.7 MPa, preferably 0.2-0.5 MPa; and / or The speed of the third mixing is 20-200 rpm, preferably 80-200 rpm.

7. The continuous polymerization method according to any one of claims 1 to 6, characterized in that The dynamic viscosity of the PAO at 40°C is 2 to 15 mm 2 / s; and / or The PAO has a freezing point of -20 to -40°C; and / or The conversion efficiency of the polymer feedstock is ≥ 85%; and / or The utilization rate of the gas phase catalyst is ≥88%.

8. A continuous polymerization system of PAO, characterized in that: The raw materials include a gas phase catalyst, an auxiliary agent and a polymerization raw material, wherein the polymerization raw material includes C8 to C12 α-olefins, and the polymerization raw material is divided into two parts, namely a first polymerization raw material and a second polymerization raw material. The PAO continuous polymerization system includes: A stirred tank (1) comprising: The stirring kettle body (11) has a first stirring feed inlet, a second stirring feed inlet, and a stirring discharge inlet; the gas phase catalyst enters the stirring kettle body (11) from the first stirring feed inlet, and the auxiliary agent and the first polymerization raw material enter the stirring kettle body (11) from the second stirring feed inlet; A first stirring paddle (12) is arranged inside the stirring tank body (11); A stirring kettle driving motor (13) connected to the first stirring paddle (12); A first cooling jacket (14) is disposed around the outer wall of the stirring tank body (11); The stirred tank (1) is used to perform a first mixing of the gas phase catalyst, the auxiliary agent and the first polymerization raw material to obtain a first mixture; In-line static mixer (2), comprising: The mixer body (21) has a static mixing feed port and a static mixing discharge port, wherein the static mixing feed port is connected to the stirring discharge port of the stirring kettle body (11); A second cooling jacket (22) is arranged around the outer wall of the mixer body (21); The pipeline static mixer (2) is used to perform a second mixing on the first mixture to obtain a second mixture; The polymerization reactor (3) comprises: A polymerization kettle body (31) has a first polymerization feed port, a second polymerization feed port, and a polymerization discharge port; the first polymerization feed port is connected to the static mixing discharge port of the mixer body (21); the second polymerization raw material enters the polymerization kettle body (31) from the second polymerization feed port; A second stirring paddle (32) is arranged inside the polymerization kettle body (31), and the second stirring paddle (32) is a three-layer paddle structure, which includes a turbine paddle (321), a self-priming stirring paddle (322), and an axial flow paddle (323) from bottom to top; A polymerization reactor driving motor (33) connected to the second stirring paddle (32); A coil (34) is arranged inside the polymerization kettle body (31); An annular wire mesh (35) is arranged on the inner wall of the polymerization kettle body (31); A third cooling jacket (36) is arranged on the outer wall of the polymerization kettle body (31); The polymerization reactor (3) is used to perform a third mixing of the second mixture and the second polymerization raw material. A polymerization reaction is carried out to obtain the PAO.

9. The continuous polymerization system according to claim 8, characterized in that: In the polymerization reactor (3), The first polymerization feed port is located below the turbine impeller; and / or The second polymerization feed port is located above the self-priming stirring paddle; and / or The polymerization outlet is located above the axial flow paddle.

10. The continuous polymerization system according to claim 8 or 9, characterized in that: Chilled water is passed through the first cooling jacket (14), the second cooling jacket (22), the coil (34), and the third cooling jacket (36) respectively and independently; Preferably, the temperature of the chilled water is 3-12° C., and the flow rate is 0.5-2 m / s.

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