A polyolefin production device and production method

Abstract

The present invention provides a polyolefin production device and a production method. The polyolefin production device includes a feed mixer and a reactor connected in sequence. The feed mixer includes a first mixing chamber and a second mixing chamber sleeved outside the first mixing chamber. A first feed pipe penetrates through the top of the first mixing chamber, and a second feed pipe is arranged on the side wall. A third feed pipe is arranged on the side wall of the second mixing chamber. Through the structural optimization of the feed mixer, the production device and production method of the present invention effectively improve the mixing effect of each material, reduce the concentration gradient in the reaction kettle, improve the reaction effect, and achieve the technical effect of significantly narrowing the molecular weight distribution of the product without affecting the catalytic performance of the catalyst itself.

Description

Technical Field

[0001] The present invention belongs to the technical field of polyolefin preparation, and particularly relates to a polyolefin production device and a production method. Background Art

[0002] Polyolefins are the products with the largest proportion in polymer materials, and have the characteristics of low cost, light specific gravity, easy molding and processing, etc., and are widely used in many fields such as industry, agriculture, military, and medicine. In these application fields, people hope that the obtained polyolefins have good mechanical properties. When using multi-active center catalysts, such as Ziegler-Natta catalysts, etc., to catalyze olefin polymerization, the obtained products generally have a wide distribution. Therefore, the molecular weight of the high molecular weight part of the product that provides mechanical properties will be very high, which affects processing. With the development of single-center catalysts and the progress of solution polymerization technology, products with a relatively narrow molecular weight distribution can gradually be obtained, but in actual production, the molecular weight distribution of the obtained products is still relatively wide. Therefore, finding a method to reduce the molecular weight distribution is particularly important for polyolefin products to exhibit good mechanical properties under lower molecular weight conditions.

[0003] Patents CN113348186A and CN114364706A narrow the molecular weight distribution of polymers by adding chain transfer agents to the reaction kettle, but to a certain extent, it will reduce the molecular weight of the catalyst catalyzing olefin polymerization, and it may be impossible to obtain polyolefins with a narrow distribution of high molecular weight. Therefore, it is particularly important to find a method to adjust the molecular weight distribution of polymers that does not affect the catalytic performance of the catalyst itself. Summary of the Invention

[0004] Aiming at the problems existing in the prior art, the purpose of the present invention is to provide a polyolefin production device and a production method. The production device makes the material mixing more uniform through the design of the mixing path of the feed mixer. After the mixed material enters the reactor, the concentration gradient can be effectively reduced, the reaction effect can be improved, and at the same time, the molecular weight distribution of the product can be significantly narrowed.

[0005] To achieve this purpose, the present invention adopts the following technical solutions:

[0006] In the first aspect, the present invention provides a polyolefin production device, which includes a feed mixer and a reactor connected in sequence. The feed mixer includes a first mixing chamber and a second mixing chamber sleeved outside the first mixing chamber;

[0007] A first feed pipe penetrates through the top of the first mixing chamber, and a second feed pipe is arranged on the side wall;

[0008] A third feed pipe is arranged on the side wall of the second mixing chamber.

[0009] In the present invention, the material of the feed mixer is a conventional material in the art, including but not limited to steel, glass, alloy or enamel steel; the cross-sections of the respective feed pipes and the mixing chamber form polygons including but not limited to circles, triangles or quadrilaterals, etc.

[0010] The following are the preferred technical solutions of the present invention, but not the limitations of the technical solutions provided by the present invention. Through the following technical solutions, the technical objectives and beneficial effects of the present invention can be better achieved and realized.

[0011] As a preferred technical solution of the present invention, the outlet end of the first feed pipe is lower than the outlet end of the second feed pipe.

[0012] Preferably, a first static mixer is provided in the first mixing chamber, and the first static mixer is located below the outlet end of the first feed pipe.

[0013] As a preferred technical solution of the present invention, the outlet end of the first mixing chamber forms a first necking portion.

[0014] Preferably, the angle formed by the first necking portion and the vertical direction is 1 to 60°, such as 1°, 5°, 10°, 15°, 20°, 25°, 30°, 35°, 40°, 45°, 50°, 55° or 60°, etc., but not limited to the listed values. Other unlisted values within this numerical range are equally applicable, and preferably 10 to 45°.

[0015] In the present invention, if the angle of the first necking portion is too large, the fluid cannot form a turbulent flow, and the mixing effect is significantly reduced.

[0016] As a preferred technical solution of the present invention, the outlet end of the third feed pipe is higher than the outlet end of the first mixing chamber.

[0017] Preferably, a second static mixer is provided in the second mixing chamber, and the second static mixer is located below the outlet end of the first mixing chamber.

[0018] In the present invention, the static mixer includes but not limited to SV type static mixer, SK type static mixer, SX type static mixer, SH type static mixer or SL type static mixer. When the raw materials enter the static mixer, two or more fluid streams are cut, sheared, rotated and remixed to achieve good dispersion and full mixing between the fluid streams.

[0019] As a preferred technical solution of the present invention, the outlet end of the second mixing chamber forms a second necking portion;

[0020] Preferably, the included angle formed by the second necking portion and the vertical direction is greater than 0° and less than 90°, such as 1°, 5°, 10°, 15°, 20°, 25°, 30°, 35°, 40°, 45°, 50°, 55°, 60°, 65°, 70°, 75°, 80°, 85° or 89°, etc., but is not limited to the listed values, and other unlisted values within this numerical range are equally applicable, preferably 10 - 70°.

[0021] In the present invention, the form of the outlet end of the second mixing chamber includes but is not limited to a necking portion, and can also be set as a horizontal end or a vertical end, that is, the case where the included angle formed by the second necking portion and the vertical direction is 0° or 90°.

[0022] As a preferred technical solution of the present invention, the first feed pipe is fixed in the first mixing chamber through a first fixing member;

[0023] Preferably, the first mixing chamber is fixed in the second mixing chamber through a second fixing member.

[0024] In the present invention, the selection of the fixing member is a conventional component, including but not limited to an ear, a perforated plate, a sieve plate, a baffle plate, a packing layer or similar equipment.

[0025] As a preferred technical solution of the present invention, the calculation formula for the inner diameter of the first feed pipe is shown in Formula I:

[0026]

[0027] The second feed pipe has the same inner diameter as the first mixing chamber, and its calculation formula is shown in Formula II:

[0028]

[0029] The calculation formula for the inner diameter of the third feed pipe is shown in Formula III:

[0030]

[0031] The calculation formula for the inner diameter of the second mixing chamber is shown in Formula VI:

[0032]

[0033] Among them, D i is the inner diameter, unit mm; Q is the production capacity of the reactor, unit t; c is the content of the comonomer (refers to monomer A below in the present invention), unit wt%; α is the ethylene conversion rate, unit %; R is the solid content rate of the product in the reactor, unit %; T is the annual operating time, unit h, generally calculated as 8000; t is the activity, unit kg / kg; ρ is the material density, unit t / m 3; u is the material flow rate, with the unit of m / h; π = 3.14.

[0034] In a second aspect, the present invention provides a method for producing polyolefin. The production method is carried out by using the polyolefin production device as described in the first aspect. The production method includes:

[0035] The first raw material and the second raw material are respectively introduced through the first feed pipe and the second feed pipe, so that the two are mixed in the first mixing cavity, and then enter the second mixing cavity to be mixed with the third raw material from the third feed pipe. After the mixing is completed, they enter the reactor to participate in the reaction;

[0036] The first raw material includes an initiator;

[0037] The second raw material includes a solvent and monomer A;

[0038] The third raw material includes monomer B.

[0039] As a preferred technical solution of the present invention, the solvent includes any one or a combination of at least two of straight-chain alkanes, isoparaffins, naphthenes or mixed alkanes with 6 - 12 carbon atoms, such as a combination of n-hexane and n-heptane, a combination of cyclohexane and n-hexane, etc.

[0040] Preferably, monomer A includes any one or a combination of at least two of propylene, 1-butene, 1-pentene, 1-hexene, 1-heptene, 1-octene, 1-nonene or 1-decene. Typical but non-limiting examples of the combination are: a combination of propylene and 1-butene, a combination of 1-butene, 1-pentene and 1-hexene, etc.

[0041] Preferably, monomer B includes ethylene.

[0042] In the present invention, generally, the raw material with the smallest demand for materials is introduced through the first feed pipe, such as the initiator in the olefin polymerization raw materials; the second feed pipe is generally for liquid feeding, such as the comonomer and solvent in the olefin polymerization raw materials. Among them, the solvent generally uses straight-chain alkanes, isoparaffins, naphthenes or mixed alkanes with 6 - 12 carbon atoms, with a density of 0.6 - 1.0 t / m3, preferably 0.65 - 0.8 t / m3; the third feed pipe can be for liquid feeding or gas feeding.

[0043] Preferably, the flow rate in the first feed pipe is 0.01 - 3 m / s, such as 0.01 m / s, 0.02 m / s, 0.05 m / s, 0.1 m / s, 0.15 m / s, 0.2 m / s, 0.4 m / s, 0.8 m / s, 1 m / s, 1.5 m / s, 2 m / s, 2.5 m / s, 2.8 m / s or 3 m / s, etc., but not limited to the listed values. Other unlisted values within this numerical range are equally applicable. Preferably, it is 0.02 - 1 m / s, and more preferably 0.1 - 0.4 m / s.

[0044] Preferably, the flow rate in the second feed pipe is 0.01 - 1 m / s, such as 0.01 m / s, 0.02 m / s, 0.05 m / s, 0.1 m / s, 0.15 m / s, 0.2 m / s, 0.4 m / s, 0.8 m / s or 1 m / s, etc., but not limited to the listed values. Other unlisted values within this numerical range are equally applicable. Preferably, it is 0.02 - 0.8 m / s, and more preferably 0.1 - 0.4 m / s.

[0045] Preferably, the flow rate in the third feed pipe is 0.01 - 1 m / s, such as 0.01 m / s, 0.02 m / s, 0.05 m / s, 0.1 m / s, 0.15 m / s, 0.3 m / s, 0.4 m / s, 0.8 m / s or 1 m / s, etc., but not limited to the listed values. Other unlisted values within this numerical range are equally applicable. Preferably, it is 0.02 - 0.8 m / s, and more preferably 0.1 - 0.4 m / s.

[0046] In the present invention, the coordination between the flow rate and the diameter of each feed pipe is very important. At the same pipe diameter, if the flow rate is too small, turbulence cannot be formed, the mixing effect is reduced, and the molecular weight distribution becomes larger; at the same pipe diameter, if the flow rate is too large, problems such as increased pressure loss, pipeline vibration, and large impact on the automatic valve switch will occur. At the same time, there is not enough time to conduct static electricity, resulting in the accumulation and increase of static charge potential.

[0047] As a preferred technical solution of the present invention, the production capacity of the reactor is 0.1 - 20 t, such as 0.1 t, 0.2 t, 0.5 t, 1 t, 3 t, 5 t, 10 t, 15 t or 20 t, etc., but not limited to the listed values. Other unlisted values within this numerical range are equally applicable. Preferably, it is 0.1 - 10 t.

[0048] The production method described in the present invention can be used to prepare polyethylene and copolymers of C3 to C10 α-olefins.

[0049] Compared with the prior art, the present invention has the following beneficial effects:

[0050] By optimizing the structure of the feed mixer in the polyolefin production device of the present invention, the mixing of materials becomes more uniform. After the mixed materials enter the reactor, the concentration gradient can be effectively reduced, the reaction effect can be improved, and at the same time, the molecular weight distribution of the product can be significantly narrowed without affecting the catalytic performance of the catalyst itself. BRIEF DESCRIPTION OF THE DRAWINGS

[0051] Figure 1 FIG. is a front view structural schematic diagram of a feed mixer in a polyolefin production device provided in Embodiment 1 of the present invention.

[0052] Figure 2 is Figure 1 a partial enlarged view of A in FIG.

[0053] Figure 3 is Figure 1 a partial enlarged view of B in FIG.

[0054] Figure 4 FIG. is a front view structural schematic diagram of a feed mixer in a polyolefin production device provided in Comparative Example 1 of the present invention.

[0055] Among them, 1 - the first mixing chamber, 11 - the first feed pipe, 12 - the second feed pipe, 13 - the first static mixer, 14 - the first fixing member, 15 - the first constriction section, 2 - the second mixing chamber, 21 - the third feed pipe, 22 - the second static mixer, 23 - the second fixing member, 24 - the second constriction section.

[0056] a - the first pipeline, b - the second pipeline, c - the third pipeline. DETAILED DESCRIPTION OF THE EMBODIMENTS

[0057] To better illustrate the present invention and facilitate understanding of its technical solutions, the present invention will be further described in detail below. However, the following embodiments are only simple examples of the present invention and do not represent or limit the scope of the protection of the present invention. The scope of protection of the present invention is subject to the claims.

[0058] The following are typical but non - restrictive embodiments of the present invention:

[0059] Embodiment 1:

[0060] This embodiment provides a polyolefin production device, including a feed mixer and a reactor connected in sequence. Among them, the structural schematic diagram of the feed mixer is as shown in FIG. Figure 1 shown, and the enlarged view of the local part A is as shown in FIG. Figure 2 shown, and the enlarged view of the local part B is as shown in FIG. Figure 3 shown.

[0061] The material of the feed mixer is 316L. The feed mixer includes a first mixing chamber 1 and a second mixing chamber 2 sleeved outside the first mixing chamber 1;

[0062] A first feed pipe 11 penetrates through the top of the first mixing chamber 1, and a second feed pipe 12 is arranged on the side wall.

[0063] A third feed pipe 21 is arranged on the side wall of the second mixing chamber 2.

[0064] The outlet end of the first feed pipe 11 is lower than the outlet end of the second feed pipe 12.

[0065] A first static mixer 13 is arranged in the first mixing chamber 1. The first static mixer 13 is an SV type static mixer and is located below the outlet end of the first feed pipe 11.

[0066] The outlet end of the first mixing chamber 1 forms a first necking portion 15; the included angle 1 formed by the first necking portion 15 and the vertical direction is 30°.

[0067] The outlet end of the third feed pipe 21 is higher than the outlet end of the first mixing chamber 1.

[0068] A second static mixer 22 is arranged in the second mixing chamber 2. The second static mixer 22 is an SV type static mixer and is located below the outlet end of the first mixing chamber 1.

[0069] The outlet end of the second mixing chamber 2 forms a second necking portion 24; the included angle 2 formed by the second necking portion 24 and the vertical direction is 50°.

[0070] The first feed pipe 11 is fixed in the first mixing chamber 1 through a first fixing member 14, and the first fixing member 14 is a perforated plate.

[0071] The first mixing chamber 1 is fixed in the second mixing chamber 2 through a second fixing member 23; the second fixing member 23 is a perforated plate.

[0072] The calculation formula for the inner diameter of the first feed pipe 11 is shown in Formula I:

[0073]

[0074] The second feed pipe 12 has the same inner diameter as the first mixing chamber 1, and its calculation formula is shown in Formula II:

[0075]

[0076] The calculation formula for the inner diameter of the third feed pipe 21 is shown in Formula III:

[0077]

[0078] The calculation formula for the inner diameter of the second mixing chamber 2 is as shown in Formula VI:

[0079]

[0080] where D i is the inner diameter, in mm; Q is the production capacity of the reactor, in t; c is the content of the comonomer (in the present invention, it refers to the monomer A below), in wt%; α is the ethylene conversion rate, in %; R is the solid content rate of the product in the reactor, in %; T is the annual operating time, in h, generally calculated as 8000; t is the activity, in kg / kg; ρ is the material density, in t / m 3 ; u is the material flow rate, in m / h; π = 3.14. The specific parameter conditions are shown in Table 1, and the specific calculation results of the pipe diameter are shown in Table 2;

[0081] Table 1

[0082]

[0083] Table 2

[0084]

[0085] Application Example 1:

[0086] This application example provides a method for producing polyolefins. The method for producing polyolefins is carried out using the polyolefin production device in Example 1. The method includes:

[0087] The first raw material and the second raw material are respectively introduced from the first feed pipe 11 and the second feed pipe 12. The two are mixed in the first static mixer 13 of the first mixing chamber 1, and then enter the second mixing chamber 2, where they are mixed with the third raw material from the third feed pipe 21 in the second static mixer 22. After mixing, they enter the reactor. The reaction temperature is 110°C and the reaction pressure is 2.4 MPa. Among them, the specific parameter conditions of the mixing process are shown in Table 3.

[0088] Table 3

[0089] Raw material Mass flow rate / (kg / h) Flow velocity / (m / s) First feed pipe Metallocene catalyst and mMAO 6.25 0.2 Second feed pipe Cyclohexane and 1 - hexene 1000 0.2 Third feed pipe Ethylene 125 0.2

[0090] Among them, the mass ratio of cyclohexane to 1-hexene is 4:1.

[0091] Example 2:

[0092] This example provides a polyolefin production device. The polyolefin production device refers to the polyolefin production device in Example 1, except that:

[0093] The included angle 1 formed by the first constriction part 15 and the vertical direction is 35°.

[0094] The included angle 2 formed by the second necking portion 24 and the vertical direction is 50°.

[0095] The inner diameters D of the first feed pipe 11, the second feed pipe 12, the third feed pipe 21, the first mixing chamber 1, and the second mixing chamber 2 i According to the design requirements, they are determined by Formula I, Formula II, Formula III, and Formula VI. The specific parameters involved in the formulas are shown in Table 4, and the specific calculation results are shown in Table 5;

[0096] Table 4

[0097]

[0098] Table 5

[0099]

[0100]

[0101] Application Example 2:

[0102] This application example provides a method for producing polyolefin. The polyolefin production method is carried out by using the polyolefin production device in Embodiment 2. The method includes:

[0103] The first raw material and the second raw material are respectively introduced from the first feed pipe 11 and the second feed pipe 12. The two are mixed in the first static mixer 13 of the first mixing chamber 1, and then enter the second mixing chamber 2, where they are mixed with the third raw material from the third feed pipe 21 in the second static mixer 22. After mixing, they enter the reactor. The reaction temperature is 130 °C and the reaction pressure is 3 MPa. Among them, the specific parameter conditions of the mixing process are shown in Table 6.

[0104] Table 6

[0105] Raw material Mass flow rate / (kg / h) Flow velocity / (m / s) First feed pipe Metallocene catalyst and mMAO 62.5 0.4 Second feed pipe n - hexane, n - heptane, n - octane and 1 - octene 7000 0.4 Third feed pipe Ethylene 903 0.4

[0106] Among them, the mass ratio of (n - hexane, n - heptane, and n - octane) to 1 - octene is 5:2.

[0107] Embodiment 3:

[0108] This embodiment provides a polyolefin production device. The polyolefin production device refers to the polyolefin production device in Embodiment 1, and the difference lies in:

[0109] The included angle 1 formed by the first necking portion 15 and the vertical direction is 35°.

[0110] The included angle 2 formed by the second necking portion 24 and the vertical direction is 50°.

[0111] The inner diameters D of the first feed pipe 11, the second feed pipe 12, the third feed pipe 21, the first mixing chamber 1, and the second mixing chamber 2 i According to the design requirements, it is determined by Formula I, Formula II, Formula III, and Formula VI. The specific parameters involved in the formulas are shown in Table 7, and the specific calculation results are shown in Table 8;

[0112] Table 7

[0113]

[0114] Table 8

[0115]

[0116] Application Example 3:

[0117] This application example provides a method for producing polyolefin. The polyolefin production method is carried out using the polyolefin production device in Example 3. The method includes:

[0118] The first raw material and the second raw material are respectively introduced through the first feed pipe 11 and the second feed pipe 12. The two are mixed in the first static mixer 13 of the first mixing chamber 1, and then enter the second mixing chamber 2, where they are mixed with the third raw material from the third feed pipe 21 in the second static mixer 22. After mixing, they enter the reactor. The reaction temperature is 130°C and the reaction pressure is 3 MPa. Among them, the specific parameter conditions of the mixing process are shown in Table 9.

[0119] Table 9

[0120] Raw material Mass flow rate / (kg / h) Flow velocity / (m / s) First feed pipe Metallocene catalyst and MAO 625 0.1 Second feed pipe n - hexane, n - heptane, n - octane and 1 - octene 61319 0.1 Third feed pipe Ethylene 9030 0.1

[0121] Among them, the mass ratio of (n - hexane, n - heptane, and n - octane) to 1 - octene is 2:1.

[0122] Example 4:

[0123] This example provides a polyolefin production device. The polyolefin production device refers to the polyolefin production device in Example 1, with the difference that:

[0124] The included angle 1 formed by the first necking part 15 and the vertical direction is 55°.

[0125] The included angle 2 formed by the second necking part 24 and the vertical direction is 60°.

[0126] The inner diameters D of the first feed pipe 11, the second feed pipe 12, the third feed pipe 21, the first mixing chamber 1, and the second mixing chamber 2 iAccording to the design requirements, it is determined by Formula I, Formula II, Formula III and Formula VI. The specific parameters involved in the formula are shown in Table 10, and the specific calculation results are shown in Table 11;

[0127] Table 10

[0128]

[0129] Table 11

[0130]

[0131] Application Example 4:

[0132] This application example provides a method for producing polyolefin. The polyolefin production method is carried out by using the polyolefin production device in Example 4. The method includes:

[0133] The first raw material and the second raw material are respectively introduced through the first feed pipe 11 and the second feed pipe 12. The two are mixed in the first static mixer 13 of the first mixing chamber 1, and then enter the second mixing chamber 2, where they are mixed with the third raw material from the third feed pipe 21 in the second static mixer 22. After mixing, they enter the reactor. The reaction temperature is 130 °C and the reaction pressure is 3 MPa. Among them, the specific parameter conditions of the mixing process are shown in Table 12.

[0134] Table 12

[0135] Raw material Mass flow rate / (kg / h) Flow velocity / (m / s) First feed pipe Metallocene catalyst and MAO 250 0.1 Second feed pipe n - hexane, n - heptane, n - octane and 1 - octene 28000 0.1 Third feed pipe Ethylene 3611 0.1

[0136] Among them, the mass ratio of (n - hexane, n - heptane and n - octane) to 1 - octene is 5:2.

[0137] Example 5:

[0138] This example provides a polyolefin production device. The polyolefin production device refers to the polyolefin production device in Example 1, and the difference is that:

[0139] The included angle 1 formed by the first constriction part 15 and the vertical direction is 45°.

[0140] The included angle 2 formed by the second constriction part 24 and the vertical direction is 70°.

[0141] The inner diameters D of the first feed pipe 11, the second feed pipe 12, the third feed pipe 21, the first mixing chamber 1 and the second mixing chamber 2 i According to the design requirements, it is determined by Formula I, Formula II, Formula III and Formula VI. The specific parameters involved in the formula are shown in Table 13, and the specific calculation results are shown in Table 14;

[0142] Table 13

[0143]

[0144] Table 14

[0145]

[0146] Application Example 5:

[0147] This application example provides a method for producing polyolefins. The method for producing polyolefins is carried out using the polyolefin production device in Example 5. The method includes:

[0148] The first raw material and the second raw material are respectively introduced through the first feed pipe 11 and the second feed pipe 12. The two are mixed in the first static mixer 13 of the first mixing chamber 1, and then enter the second mixing chamber 2, where they are mixed with the third raw material from the third feed pipe 21 in the second static mixer 22. After mixing, they enter the reactor. The reaction temperature is 130 °C and the reaction pressure is 3 MPa. Among them, the specific parameter conditions of the mixing process are shown in Table 15.

[0149] Table 15

[0150] Raw material Mass flow rate / (kg / h) Flow velocity / (m / s) First feed pipe Metallocene catalyst and mMAO 125 0.02 Second feed pipe n - hexane, n - heptane, n - octane and 1 - octene 14000 0.02 Third feed pipe Ethylene 1805 0.02

[0151] Among them, the mass ratio of (n - hexane, n - heptane, and n - octane) to 1 - octene is 5:2.

[0152] Example 6:

[0153] This example provides a polyolefin production device. The polyolefin production device refers to the polyolefin production device in Example 1, and the difference is that:

[0154] The included angle 1 formed by the first constriction part 15 and the vertical direction is 35°.

[0155] The included angle 2 formed by the second constriction part 24 and the vertical direction is 55°.

[0156] The inner diameters D of the first feed pipe 11, the second feed pipe 12, the third feed pipe 21, the first mixing chamber 1, and the second mixing chamber 2 i According to the design requirements, they are determined by Formula I, Formula II, Formula III, and Formula VI. The specific parameters involved in the formulas are shown in Table 16, and the specific calculation results are shown in Table 17;

[0157] Table 16

[0158]

[0159] Table 17

[0160]

[0161] Application Example 6:

[0162] This application example provides a method for producing polyolefins. The polyolefin production method is carried out using the polyolefin production device in Example 6. The method includes:

[0163] The first raw material and the second raw material are respectively introduced through the first feed pipe 11 and the second feed pipe 12. The two are mixed in the first static mixer 13 of the first mixing chamber 1, and then enter the second mixing chamber 2, where they are mixed with the third raw material from the third feed pipe 21 in the second static mixer 22. After mixing, they enter the reactor. The reaction temperature is 130 °C and the reaction pressure is 3 MPa. Among them, the specific parameter conditions of the mixing process are shown in Table 18.

[0164] Table 18

[0165] Raw material Mass flow rate / (kg / h) Flow velocity / (m / s) First feed pipe Metallocene catalyst and mMAO 125 0.8 Second feed pipe n - hexane, n - heptane, n - octane and 1 - octene 14000 0.8 Third feed pipe Ethylene 1805 0.8

[0166] Among them, the mass ratio of (n - hexane, n - heptane, and n - octane) to 1 - octene is 7:2.

[0167] Comparative Example 1:

[0168] This comparative example provides a polyolefin production device, including a feed mixer and a reactor connected in sequence. Among them, the structural schematic diagram of the feed mixer is as Figure 4 shown;

[0169] The feed mixer includes a first pipeline a, a first static mixer 13, and a second static mixer 22 connected in sequence;

[0170] The first static mixer is also connected to a second pipeline b; the second static mixer is also connected to a third pipeline c.

[0171] Comparative Application Example 1:

[0172] This comparative application example provides a method for producing polyolefins. The production method refers to the production method in Example 1. Among them, the first pipeline a corresponds to the first feed pipe 11 in Example 1, the second pipeline b corresponds to the second feed pipe 12 in Example 1, and the third pipeline c corresponds to the third feed pipe 21 in Example 1. The inner diameter of the pipeline, the type of raw material, the feed flow rate, the feed velocity, and the reaction conditions are all the same.

[0173] Using a GPC - IR high - temperature gel permeation chromatograph to measure the molecular weight distribution results of the products obtained in the reactors in Application Examples 1 - 6 and Comparative Application Example 1 at different time periods, the molecular weight distribution range of the products is obtained. The test results are shown in Table 19.

[0174] Among them, the molecular weight distribution of the product = weight - average molecular weight / number - average molecular weight

[0175] Table 19

[0176] Molecular weight distribution Application Example 1 2.3-2.5 Application Example 2 2.2-2.4 Application Example 3 2.1-2.3 Application Example 4 2.1-2.3 Application Example 5 2.2-2.4 Application Example 6 2.2-2.3 Comparative Application Example 1 2.5-2.8

[0177] Analysis of Application Examples 1 - 6 shows that by using the production device and production method of the present invention, the mixing effect of each material can be effectively improved, the concentration gradient in the reaction kettle can be reduced, the reaction effect can be improved, and the technical effect of significantly narrowing the molecular weight distribution of the product can be achieved without affecting the catalytic performance of the catalyst itself.

[0178] Analysis of Application Example 1 and Comparative Application Example 1 shows that the mixing effect of simple co - current mixing is poor, resulting in a wide molecular weight distribution of the product.

[0179] The present invention uses the above - mentioned embodiments to illustrate the device and detailed method of the present invention. However, the present invention is not limited to the above - mentioned device and detailed method, that is, it does not mean that the present invention must rely on the above - mentioned device and detailed method to be implemented. Those skilled in the art should understand that any improvement to the present invention, equivalent replacement of the operation of the present invention, addition of auxiliary operations, selection of specific methods, etc. all fall within the protection scope and disclosure scope of the present invention.

Claims

1. A polyolefin production device, the polyolefin production device includes a feed mixer and a reactor connected in sequence, characterized in that, The feed mixer includes a first mixing chamber and a second mixing chamber sleeved outside the first mixing chamber; A first feed pipe penetrates through the top of the first mixing chamber, and a second feed pipe is arranged on the side wall; The outlet end of the first feed pipe is lower than the outlet end of the second feed pipe; The outlet end of the first mixing chamber forms a first necking portion; The included angle formed by the first necking portion and the vertical direction is 1 to 60°; A third feed pipe is arranged on the side wall of the second mixing chamber; The outlet end of the third feed pipe is higher than the outlet end of the first mixing chamber; The calculation formula for the inner diameter of the first feed pipe is as shown in Formula I: Formula I The second feed pipe has the same inner diameter as the first mixing chamber, and its calculation formula is as shown in Formula II: Formula II The calculation formula for the inner diameter of the third feed pipe is as shown in Formula III: Formula III The calculation formula for the inner diameter of the second mixing chamber is as shown in Formula VI: Formula VI Among them, is the inner diameter, in mm; Q is the production capacity of the reactor, in t; c is the comonomer content, in wt%; α is the ethylene conversion rate, in %; R is the solid content rate of the product in the reactor, in %; T is the annual operating time, in h, calculated as 8000; t is the activity, in kg / kg; ρ is the material density, in t / m3; u is the material flow rate, in m / h; ; The flow rate in the first feed pipe is 0.01 - 3 m / s; The flow rate in the second feed pipe is 0.01 - 1 m / s; The flow rate in the third feed pipe is 0.01 - 1 m / s.

2. The polyolefin production device according to claim 1, characterized in that, A first static mixer is arranged in the first mixing chamber, and the first static mixer is located below the outlet end of the first feed pipe.

3. The polyolefin production device according to claim 1, characterized in that, The included angle formed by the first necking portion and the vertical direction is 10 to 45°; 4. The polyolefin production device according to claim 1, characterized in that, A second static mixer is arranged in the second mixing chamber, and the second static mixer is located below the outlet end of the first mixing chamber.

5. The polyolefin production device according to claim 1, characterized in that, The outlet end of the second mixing chamber forms a second necking portion; 6. The polyolefin production device according to claim 5, characterized in that, The included angle formed by the second necking portion and the vertical direction is greater than 0° and less than 90°; 7. The polyolefin production device according to claim 6, characterized in that, The included angle formed by the second necking portion and the vertical direction is 10 to 70°; 8. The polyolefin production device according to claim 1, characterized in that, The first feed pipe is fixed in the first mixing chamber through a first fixing member; 9. The polyolefin production device according to claim 1, characterized in that, The first mixing chamber is fixed in the second mixing chamber through a second fixing member; 10. A method for producing polyolefin, characterized in that, The production method is carried out by using the polyolefin production device as described in any one of claims 1 - 9, and the production method includes: Feeding the first raw material and the second raw material into the first mixing chamber through the first feed pipe and the second feed pipe respectively, mixing the two in the first mixing chamber, then entering the second mixing chamber, mixing with the third raw material from the third feed pipe, and entering the reactor to participate in the reaction after mixing is completed; The first raw material includes an initiator; The second raw material includes a solvent and monomer A; The third raw material includes monomer B; 11. The production method according to claim 10, wherein, The solvent includes any one or a combination of at least two of straight-chain alkanes, isoparaffins, naphthenes or mixed alkanes with C6 - C12; 12. The production method according to claim 10, wherein, Monomer A includes any one or a combination of at least two of propylene, 1-butene, 1-pentene, 1-hexene, 1-heptene, 1-octene, 1-nonene or 1-decene; 13. The production method according to claim 10, wherein, Monomer B includes ethylene; 14. The production method according to claim 10, wherein, The flow rate in the first feed pipe is 0.01 - 3 m / s; 15. The production method according to claim 14, wherein, The flow rate in the first feed pipe is 0.02 - 1 m / s; 16. The production method according to claim 15, wherein, The flow rate in the first feed pipe is 0.1 - 0.4 m / s; 17. The production method according to claim 10, wherein, The flow rate in the second feed pipe is 0.01 - 1 m / s; 18. The production method according to claim 17, wherein, The flow rate in the second feed pipe is 0.02 - 0.8 m / s; 19. The production method according to claim 18, wherein, The flow rate in the second feed pipe is 0.1 - 0.4 m / s.

20. The production method according to claim 10, wherein, The flow rate in the third feed pipe is 0.01 - 1 m / s.

21. The production method according to claim 20, wherein, The flow rate in the third feed pipe is 0.02 - 0.8 m / s.

22. The production method according to claim 21, wherein, The flow rate in the third feed pipe is 0.1 - 0.4 m / s.

23. The production method according to claim 10, wherein, The production capacity of the reactor is 0.1 - 20 t.

24. The production method according to claim 23, wherein, The production capacity of the reactor is 0.1 - 10 t.

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