Tubular reactor and system and olefin polymerization method

Abstract

The invention belongs to the technical field of olefin polymerization, and relates to a tubular reactor and an olefin polymerization method with controllable load distribution. The reactor comprises a slurry circulating pump, a closed loop pipe, a feed port, a slurry discharge port and a guide vane component, and a slurry guide vane is arranged in the guide vane component. By adopting the tubular reactor disclosed by the invention, the heat transfer efficiency of the reactor can be improved, the scaling rate of the tube wall is reduced, and the concentration of discharged slurry can be further controlled; in addition, for a production device with a plurality of tubular reactors connected in series, the problem that the concentration deviation of slurry in the tubular reactors is too large can be solved, load distribution control among the tubular reactors is achieved, and the overall production load of the device is further improved.

Description

Technical Field

[0001] This invention belongs to the field of olefin polymerization technology, specifically, it relates to a tubular reactor, a tubular reactor system based on the tubular reactor, and an olefin polymerization method using the tubular reactor system. Background Technology

[0002] In 2023, global polypropylene production capacity exceeded 100 million tons per year. Basell's Spheripol loop / gas-phase process accounted for 50% of global polypropylene production capacity. In China, ST and Spheripol loop polymerization plants accounted for more than one-third of the total production capacity, making them the mainstream production technologies. Borstar polyethylene process, Innovene S polyethylene process, and MarTECH polyethylene process also use tubular reactors.

[0003] In tubular reactors, polymers are blended with diluents or monomers in a suspension. The polymer slurry is typically discharged intermittently or continuously. Intermittent discharge usually involves one or more settling pipes at the bottom of the reactor to collect polymer particles, and the enriched slurry is discharged to subsequent reaction or separation systems via intermittent valve opening and closing. This intermittent discharge method often affects the smooth flow of slurry between two tubular reactors, and the polymer particle concentration in the settling pipes should not exceed a certain value; otherwise, there will not be enough diluent or monomer gas for polymer transport during discharge. Continuous discharge typically involves an eccentric ball valve at the bottom of the reactor, maintaining a certain opening to ensure continuous discharge of the polymer slurry. Compared to intermittent discharge, this method allows for a higher polymer particle concentration within the reactor; therefore, current technologies mostly employ continuous discharge.

[0004] Polyolefin catalysts are polymerization-activity-degrading catalysts, typically exhibiting a reaction rate decline to half or even lower than the initial rate after 1-2 hours of polymerization. In current processes, the residence time in a single tubular reactor is approximately 1-2 hours. Therefore, the catalytic kinetics can lead to an excessively high load on the first tubular reactor.

[0005] Polymer particles have a higher density than diluents or monomers. Due to centrifugal force, the polymer particle concentration is typically higher outside the bends and on the outer side of the straight section following the bend in a tubular reactor. Therefore, the discharge point of the tubular reactor is usually located at the bend or on the straight section following the bend, especially in the bend area where the slurry discharge from the first tubular reactor is located. However, in polymerization processes with multiple tubular reactors connected in series, if adjusting the discharge point of the first tubular reactor is not ideal, the polymer slurry concentration in the first reactor may still be significantly higher than that in subsequent tubular reactors, making product composition control difficult.

[0006] To improve or solve the above problems, the main technical means at present is to increase the flow rate of diluent or monomer in the first tubular reactor and shorten the residence time. Another means is to develop catalysts with slow reaction rate decay, but these methods have not completely solved the problem of load distribution among multiple tubular reactors.

[0007] Increasing the polymer particle concentration within the reactor translates to a higher space-time yield, meaning more polymer can be produced per unit volume and per unit time. For production units with multiple tubular reactors connected in series, maintaining a high polymer slurry concentration in multiple reactors simultaneously can increase the unit's production load and efficiency, thereby saving production costs. Summary of the Invention

[0008] To address the aforementioned problems, this invention provides a novel tubular reactor and its system, along with a method for controlling the discharge. The tubular reactor of this invention improves reactor heat transfer efficiency, reduces internal scaling, and further enables control over the concentration of the discharged slurry.

[0009] A first aspect of the present invention provides a tubular reactor, the reactor comprising: a slurry circulation pump, a closed-loop annular pipe, a feed inlet, a slurry discharge outlet, and a guide vane component; wherein a slurry guide vane is disposed within the guide vane component.

[0010] A second aspect of the present invention provides a tubular reactor system comprising at least two tubular reactors connected in series, wherein at least one tubular reactor is the tubular reactor described above.

[0011] A third aspect of the present invention provides an olefin polymerization method, which is carried out in the above-described tubular reactor or tubular reactor system.

[0012] The beneficial effects of the present invention are as follows: the tubular reactor of the present invention can improve the heat transfer efficiency of the reactor, reduce the scaling rate of the tube wall, and further, can also achieve control of the concentration of the effluent slurry; for production devices with multiple tubular reactors connected in series, it can also solve the problem of excessive slurry concentration deviation in multiple tubular reactors, realize load distribution control among multiple tubular reactors, and thus improve the overall production load of the device.

[0013] Other features and advantages of the present invention will be described in detail in the following detailed description section. Attached Figure Description

[0014] Exemplary embodiments of the present invention will be described in more detail with reference to the accompanying drawings.

[0015] Figure 1 This is a structural diagram of a guide vane component inside a tubular reactor according to a specific embodiment of the present invention.

[0016] Figure 2 This is a structural diagram of the guide vane component inside the tubular reactor in another specific embodiment of the present invention.

[0017] Figure 3 This is a diagram of a series tubular reactor production apparatus according to a specific embodiment of the present invention.

[0018] Explanation of reference numerals in the attached drawings: 11 Component flange, 12 slurry guide vane, 13 Component outer wall, D11 Guide vane component inner diameter, L12 Slurry guide vane length, L13 Guide vane component length, L14 Slurry guide vane pitch; 21 Component flange, 22 Slurry guide vane, 23 Component outer wall, D21 Guide vane component inner diameter, L22 Slurry guide vane length, L23 Guide vane component length, L24 Slurry guide vane pitch.

[0019] 1 First tubular reactor, 2 Second tubular reactor, 101 First slurry circulation pump, 102 First tubular reactor heat dissipation jacket, 103 First guide vane component, 104 Catalyst feed line, 105 First propylene feed line, 106 First tubular reactor #1 discharge line, 107 First tubular reactor #2 discharge line, 108 First three-way valve, 201 Second slurry circulation pump, 202 Second tubular reactor heat dissipation jacket, 203 Second guide vane component, 204 Second propylene feed line, 205 Second tubular reactor #1 discharge line, 206 Transmission line, 207 Second tubular reactor #2 discharge line, 208 Second three-way valve, L101 Distance from the slurry outlet of the first tubular reactor #1 discharge line 106 to the first guide vane component, L201 Distance from the slurry outlet of the second tubular reactor #1 discharge line to the second guide vane component. Detailed Implementation

[0020] The following provides a detailed description of specific embodiments of the present invention. It should be understood that the specific embodiments described herein are for illustrative and explanatory purposes only and are not intended to limit the scope of the invention.

[0021] A first aspect of the present invention provides a tubular reactor, the reactor comprising: a slurry circulation pump, a closed-loop annular pipe, a feed inlet, a slurry discharge outlet, and a guide vane component; wherein a slurry guide vane is disposed within the guide vane component.

[0022] According to the present invention, the slurry circulation pump provides circulation power for the polymer slurry, ensuring uniform dispersion of the polymer in the slurry. Its specific location is not particularly limited. Typically, for ease of arrangement, it is placed at the bottom of the tubular reactor. According to a specific embodiment of the present invention, the feed inlet is located at the bottom of the loop pipe, and the slurry circulation pump is located at the junction of the straight and curved sections of the loop pipe.

[0023] According to the present invention, one objective of the guide vane component is to reduce the boundary layer effect of the polymer slurry in the tubular reactor, improve heat transfer efficiency, and reduce the risk of fouling on the tube wall. At least one guide vane component is provided. With the action of the guide vane component, the heat transfer efficiency of the tubular reactor is increased by at least 1%, that is, the heat transfer efficiency of the tubular reactor is increased by at least 1% compared to when no guide vane component is provided, preferably by at least 3%.

[0024] The heat transfer efficiency is defined by equation (1):

[0025]

[0026] Where F is the mass flow rate of the heat removal medium in the jacket of the tubular reactor, C is the specific heat capacity of the heat removal medium, t1 is the outlet temperature of the heat removal medium, t2 is the inlet temperature of the heat removal medium, and T is the temperature of the polymer slurry inside the tubular reactor. When comparing the heat transfer efficiency of two tubular reactors, it is necessary to ensure that parameters such as feed, residence time, and polymer content are consistent between the two reactors to ensure consistency in the amount of heat released.

[0027] According to the present invention, the slurry guide vane is an internal component with centrifugal action. Another purpose of its arrangement is to enable the high-speed flowing polymer slurry to achieve a centrifugal effect under its action, thereby concentrating the polymer slurry near the slurry outlet pipe wall, that is, increasing the solid content of the slurry.

[0028] According to a preferred embodiment of the present invention, at least one slurry outlet is located adjacent to and downstream of the guide vane component, in accordance with the material flow direction within the reactor. By controlling the slurry discharge method, the concentration of the slurry discharged from the tubular reactor can be adjusted, thereby achieving load distribution control among multiple tubular reactors.

[0029] The slurry guide vane can be in the form of a planar or curved internal component, preferably a curved internal component, and more preferably a fan blade, paddle blade, single-curved spiral blade, or hyperboloid spiral blade, but is not limited thereto. The guide vane should have a simple structure and a smooth surface to avoid dead zones.

[0030] According to the present invention, the guide vane component can be disposed within the annular pipe or can be part of the annular pipe. In a preferred embodiment of the present invention, the guide vane component further includes an outer wall that surrounds and is fixedly connected to the slurry guide vane. The present invention does not particularly limit the connection method between the slurry guide vane and the outer wall of the component. Specifically, the slurry guide vane and the outer wall of the component can be fixedly connected by a slot connection, a threaded connection, or welding. This fixes the slurry guide vane at a specific position within the annular pipe.

[0031] According to a preferred embodiment of the present invention, the outer wall of the component is part of a ring pipe, and its two ends are connected to the rest of the ring pipe; when it is part of a ring pipe, the outer wall of the component is cylindrical, and its length is usually greater than the length of the slurry guide vane, and it may have a certain thickness.

[0032] The present invention does not particularly limit the connection method between the two ends of the outer wall of the component and the rest of the ring pipe, but flange or threaded connection is preferred.

[0033] pass Figure 1 and Figure 2 Embodiments of the guide vane component of the present invention will be described, but the invention is not limited thereto.

[0034] According to one embodiment of the present invention, the slurry guide vane 12 is configured as follows: Figure 1 The diagram shows a single-curved spiral blade, with the slurry guide vane 12 welded to the outer wall 13 of the component. The guide vane component is connected to the wall of the tubular reactor's annular pipe via a component flange 11. When replacement is required, the guide vane component can be replaced entirely by disassembling the flange.

[0035] According to one embodiment of the present invention, the ratio of the pitch L14 of the slurry guide vane to the inner diameter D11 of the guide vane component is 0.2-6, preferably 0.5-4; the ratio of the length L12 of the slurry guide vane to the pitch L14 of the slurry guide vane is 0.05-5, preferably 0.1-3; and the ratio of the length L13 of the guide vane component to the length L12 of the slurry guide vane is ≤2, preferably ≤1.5.

[0036] According to another embodiment of the present invention, the slurry guide vane 22 is configured to... Figure 2 The diagram shows a hyperboloidal helical blade, with the slurry guide vane 22 connected to the outer wall 23 of the component via a slot. The guide vane component is connected to the wall of the tubular reactor's annular pipe via the component flange 21. When replacement is needed, the slurry guide vane can be replaced by inserting and removing it from the slot.

[0037] According to another embodiment of the present invention, the ratio of the pitch L24 of the slurry guide vane to the inner diameter D21 of the guide vane component is 0.2-6, preferably 0.5-4; the ratio of the length L22 of the slurry guide vane to the pitch L24 of the slurry guide vane is 0.05-5, preferably 0.1-3; and the ratio of the length L23 of the guide vane component to the length L22 of the slurry guide vane is ≤2, preferably ≤1.5.

[0038] In both of the above embodiments, since the outer wall of the component is cylindrical, the inner diameter of the guide vane component is equal to the inner diameter of the outer wall of the component, and the length of the guide vane component is equal to the length of the outer wall of the component, that is, the longest distance along the spiral axis of the slurry guide vane.

[0039] The present invention does not particularly limit the outer diameter of the slurry guide vane (i.e., the maximum diameter of the cylindrical surface formed by the rotation of the slurry guide vane). Its size can be equal to or smaller than the inner diameter of the outer wall of the component.

[0040] According to the present invention, the guide vane component can be arranged at any position in the tubular reactor, preferably in the straight section of the annular pipe. The purpose of setting the guide vane component is to increase the concentration of the polymer slurry at the slurry outlet, so that it can be better controlled in concentration when it enters the downstream reactor. Therefore, it is necessary to set the parameters of the guide vane component reasonably. Preferably, the positional distance L between the guide vane component and the adjacent slurry outlet is ≤10m, more preferably ≤5m. The ratio of the positional distance L between the guide vane component and the adjacent slurry outlet to the diameter D of the tubular reactor is ≤10, more preferably ≤5.

[0041] By controlling the above parameters, the concentration of polymer slurry at the slurry outlet can be better regulated.

[0042] According to the present invention, the ratio of the length to the diameter of the tubular reactor is ≤1000, preferably ≤500. The diameter D of the tubular reactor is 100-1200 mm, preferably 150-1000 mm, and the diameter preferably does not include the variable diameter section.

[0043] The length of a tubular reactor usually refers to the circumference of the ring tube, and this definition is also adopted in this invention.

[0044] In the tubular reactor of the present invention, there can be one or more feed inlets. Each feed medium can be fed individually or in combination. The same medium or combination can also be fed at multiple points.

[0045] According to the present invention, there may be one or more slurry outlets, and their specific locations are not particularly limited, as long as at least one is located downstream of the guide vane member. Specifically, the slurry outlets may be located at one or more locations in the middle, lower middle, and bottom of the tubular reactor. When multiple tubular reactors are used, the slurry outlets of different tubular reactors may be located at different positions.

[0046] When there is only one slurry outlet in a tubular reactor, the slurry concentration at the outlet can be controlled by adjusting the speed of the slurry circulation pump, thereby changing the flow rate of the polymer slurry.

[0047] For the purpose of controlling the polymer slurry concentration in each tubular reactor, the slurry inlet is preferably provided in multiple locations, at least two, one of which is located in a conventional position, generally at the bottom of the reactor, and the other is located near the downstream of the guide vane component.

[0048] According to the present invention, the annular tube is typically provided with a jacket for introducing a heat-relieving or heat-giving medium to provide or remove heat for the reaction process. The medium is preferably one or a mixture of water, alcohol, oil, hydrocarbons, fluorocarbons, and chlorocarbons.

[0049] A second aspect of the present invention provides a tubular reactor system comprising at least two tubular reactors connected in series, wherein at least one tubular reactor is the tubular reactor described above.

[0050] In the tubular reactor system of the present invention, all tubular reactors may be of the type described above, or some tubular reactors may be of the type described above. For example, all reactors except the last tubular reactor may be of the type described above.

[0051] According to the present invention, multiple tubular reactors can be connected by transmission lines. The preceding tubular reactor can be directly connected to the following tubular reactor, or it can be connected to the connecting pipeline of the following tubular reactor. The connecting pipeline is the external circulation pipeline of the slurry from one zone to another in the following tubular reactor, which is well known to those skilled in the art.

[0052] According to the present invention, the inner diameters of the multiple tubular reactors may be the same or different, preferably the same.

[0053] According to one specific embodiment of the present invention, the tubular reactor system includes two tubular reactors connected in series;

[0054] In the first tubular reactor, the guide vane component is located in the straight pipe section within half of the pipeline after the outlet of the slurry circulation pump. The first tubular reactor is provided with two slurry outlets, one of which is located in the middle of the reactor and the other is located at the bottom of the reactor.

[0055] In the second tubular reactor, the guide vane component is located in the straight pipe section of the latter half of the slurry circulation pump outlet pipe. The second tubular reactor is provided with two slurry outlets. The slurry outlet near the guide vane component is located in the lower middle part of the straight pipe section of the ring pipe, and the other is located at the bottom of the reactor.

[0056] The first tubular reactor and the second tubular reactor are connected by a transmission line. One end of the transmission line is connected to the two slurry outlets of the first tubular reactor through a three-way valve, and the other end is connected to the feed inlet of the second tubular reactor.

[0057] "The guide vane component is located within half the length of the pipeline after the outlet of the slurry circulation pump" means that the distance the material travels from the slurry circulation pump to the guide vane component is less than half the total length of the pipeline. Conversely, "The guide vane component is located in the latter half of the pipeline after the outlet of the slurry circulation pump" means that the distance the material travels from the slurry circulation pump to the guide vane component is greater than half the total length of the pipeline.

[0058] A third aspect of the present invention provides an olefin polymerization method, which is carried out in the above-described tubular reactor or tubular reactor system.

[0059] In this invention, the feed to the tubular reactor can be conventional materials, including but not limited to one or more of olefins, comonomers, diluents, catalysts, cocatalysts, activators, chain transfer agents, additives, antistatic agents, and co-reactants.

[0060] When the method is carried out in a tubular reactor system, the tubular reactor system includes at least two tubular reactors. The feed to the first tubular reactor includes, but is not limited to, one or more of olefins, comonomers, diluents, catalysts, cocatalysts, activators, chain transfer agents, additives, antistatic agents, and co-reactants. The feed to subsequent tubular reactors includes, but is not limited to, one or more of olefins, comonomers, diluents, cocatalysts, activators, chain transfer agents, additives, antistatic agents, and co-reactants.

[0061] This invention relates to a method for the continuous polymerization of olefins, particularly α-monoolefins, in a tubular reactor to prepare polymers. The α-monoolefin is preferably C2 to C3. 10 At least one of monounsaturated olefins. Olefins, diluents, and catalyst-containing polymer particles are the main components forming the polymer slurry.

[0062] The catalyst used for polymerization can be selected from conventional polyolefin catalysts in the art, such as Ziegler-Natta catalysts, chromium-based catalysts, metallocene catalysts, non-metallocene catalysts, composite catalysts, and at least one of other polyolefin catalysts with catalytic activity.

[0063] According to the present invention, the catalyst slurry entering the first tubular reactor may be pre-complexed or not; the catalyst slurry may be pre-polymerized or not.

[0064] According to the present invention, in the polymerization method consisting of tubular reactors connected in series, the polymer content in each tubular reactor can be 5-70 wt%, preferably 20-60 wt%.

[0065] The residence time of a single tubular reactor can be 0.5-4 hours, preferably 0.6-3 hours.

[0066] In this invention, the residence time of the tubular reactor is the ratio of the reactor volume to the volumetric flow rate of the polymer slurry.

[0067] According to the present invention, the high-speed flow of polymer slurry within the tubular reactor ensures uniform dispersion of the polymer within the slurry and simultaneously provides the driving force for centrifugal concentration of the slurry at the slurry guide vanes. The flow rate of the polymer slurry within each tubular reactor can be the same or different, each independently ranging from 2-15 m / s, preferably 3-12 m / s. The slurry guide vanes can increase the polymer concentration at the slurry outlet position on the tube wall within the tubular reactor by 5-100%, preferably 5-50%.

[0068] The operating conditions of the tubular reactor can be conventional. Specifically, the polymerization temperature inside the tubular reactor is 20-150℃, preferably 20-110℃, and the operating pressure of the tubular reactor is 0.5-10MPa(g), preferably 1.0-8.0MPa(g).

[0069] When a single tubular reactor is used for the reaction, the above-mentioned limitations on process conditions apply to that tubular reactor.

[0070] According to the present invention, the slurry outlet can continuously or intermittently discharge a polymer slurry consisting of polymer particles and unreacted feed into a subsequent reactor or downstream system. Continuous discharge of the polymer slurry is preferred.

[0071] By controlling the slurry guide vane structure, slurry circulation velocity, and discharge point location, the concentration of the slurry discharged from the tubular reactor can be regulated. For a polymerization unit composed of multiple tubular reactors of this invention, the above-mentioned regulation methods can be used to achieve load distribution control among the multiple tubular reactors, thereby improving the overall production load of the unit.

[0072] According to a specific embodiment of the present invention, the polymerization method employs a series combination of two tubular reactors, wherein the ratio of the load P1 of the first tubular reactor to the load P2 of the second tubular reactor is 20 / 80-90 / 10, preferably 40 / 60-80 / 20.

[0073] The reactor load is the mass of polymer produced in the tubular reactor per unit time. The load of the first tubular reactor is equal to the product of the total feed mass flow rate and the polymer slurry mass fraction. The product of the total feed mass flow rate and the polymer slurry mass fraction of the second tubular reactor is the total load of the first and second tubular reactors. The difference between the total load and the load of the first tubular reactor is the load of the second tubular reactor.

[0074] To provide a detailed description of the second and third aspects of the present invention, the present invention is described through... Figure 3 This description is provided as one embodiment of the present invention and does not limit the scope of the invention.

[0075] According to one embodiment of the present invention, a dual-tube reactor system is adopted. In the first tube reactor 1, the first guide vane component 103 is located within half the pipeline after the outlet of the slurry circulation pump 101. The ratio of the distance L101 from the slurry outlet corresponding to the first tube reactor 1# discharge line 106 to the guide vane component to the reactor diameter D is ≤5. The catalyst slurry enters the first tube reactor 1 through the catalyst feed line 104, and propylene enters the first tube reactor 1 through the first propylene feed line 105. The first tube reactor 1# discharge line 106 and the first tube reactor 2# discharge line 107 merge through the first three-way valve 108 and enter the second tube reactor 2. The first three-way valve 108 can realize the discharge of 106 or 107 individually or simultaneously. Hot water is introduced into the first tube reactor heat dissipation jacket 102 for heat exchange.

[0076] In the second tubular reactor 2, the second guide vane component 203 is located in the latter half of the outlet pipeline of the slurry circulation pump 201; the ratio of the distance L201 from the slurry outlet corresponding to the slurry outlet of the first tubular reactor 1# discharge line 205 to the reactor diameter is ≤5; the slurry from the first tubular reactor enters the second tubular reactor 2 via the transmission line 206, and propylene enters the second tubular reactor 2 via the second propylene feed line 204; the second tubular reactor 1# discharge line 205 and the second tubular reactor 2# discharge line 207 merge through the second three-way valve 208 and enter the subsequent equipment; the second three-way valve 208 can realize the discharge of 205 or 207 individually or simultaneously; hot water is introduced into the cooling jacket 202 of the second tubular reactor for heat exchange.

[0077] To increase the load ratio of the second tubular reactor 2, the discharge line 106 of the first tubular reactor 1#, the first three-way valve 108, and the transmission line 206 channel are activated.

[0078] The present invention will be further described below with reference to the embodiments, but the scope of the present invention is not limited to these embodiments.

[0079] Example 1

[0080] A 50 kg / hr loop propylene polymerization unit mainly includes a prepolymerization reactor, a first tubular reactor (150 L), and a second tubular reactor (150 L). The inner diameter D of each tubular reactor is 150 mm. Figure 3 As shown.

[0081] The first tubular reactor 1 includes: a first slurry circulation pump 101, a closed-loop ring pipe, two feed inlets, two slurry outlets, a first guide vane component 103, and a first tubular reactor heat removal jacket 102 (through which hot water is introduced for heat exchange).

[0082] The first slurry circulation pump 101 is installed at the connection between the straight pipe section and the curved pipe section at the bottom of the tubular reactor.

[0083] The two inlets are respectively connected to the catalyst feed line 104 and the first propylene feed line 105.

[0084] Two slurry outlets are located in the middle and bottom of the reactor, respectively, and are connected to the No. 1 discharge line 106 of the first tubular reactor and the No. 2 discharge line 107 of the first tubular reactor.

[0085] The first guide vane component 103 is located within half the length of the pipeline after the outlet of the slurry circulation pump 101, specifically in the straight pipe section between the slurry circulation pump 101 and the middle slurry outlet, and close to the middle slurry outlet. The slurry guide vane in the first guide vane component 103 adopts a single-curved spiral vane, and the ratio of the slurry guide vane pitch L14 to the guide vane component inner diameter D11 is 1. The ratio of the slurry guide vane length L12 to the slurry guide vane pitch L14 is 0.5. The ratio of the distance L101 from the slurry outlet corresponding to the first tubular reactor 1# discharge line 106 to the first guide vane component is 2.

[0086] The discharge lines 106 and 107 of the first tubular reactor 1 and 2 are connected by a first three-way valve 108 to form a transmission line 206, which then enters the second tubular reactor 2. The first three-way valve 108 can allow either 106 or 107 to discharge individually or simultaneously.

[0087] The second tubular reactor 2 includes: a second slurry circulation pump 201, a closed-loop ring pipe, two feed inlets, two slurry outlets, a second guide vane component 203, and a second tubular reactor heat removal jacket 202 (through which hot water is introduced for heat exchange).

[0088] The second slurry circulation pump 201 is installed at the connection between the straight pipe section and the curved pipe section at the bottom of the tubular reactor.

[0089] The two inlets are connected to the second propylene feed line 204 and the transmission line 206, respectively.

[0090] The two slurry outlets are located in the lower part of the straight pipe section of the reactor and at the bottom of the reactor, respectively, and are connected to the discharge line 205 of the second tubular reactor 1 and the discharge line 207 of the second tubular reactor 2.

[0091] The second guide vane component 203 is installed in the straight pipe section of the latter half of the outlet pipe of the slurry circulation pump 201; the slurry guide vane in the second guide vane component 203 adopts a single-curved spiral vane, the ratio of the slurry guide vane pitch L14 to the guide vane component inner diameter D11 is 1; the ratio of the slurry guide vane length L12 to the slurry guide vane pitch L14 is 0.5; the ratio of the distance L201 from the slurry outlet corresponding to the discharge line 205 of the second tubular reactor to the second guide vane component is 4 to the diameter D of the tubular reactor.

[0092] The discharge line 205 of the second tubular reactor #1 and the discharge line 207 of the second tubular reactor #2 are connected to the downstream equipment via the second three-way valve 208. The second three-way valve 208 can allow discharge from 205 or 207 individually or simultaneously.

[0093] Example 2

[0094] Propylene polymerization was carried out on the 50 kg / hr loop propylene polymerization apparatus provided in Example 1.

[0095] The catalyst (HR catalyst, Sinopec Aoda Branch) has a flow rate of 0.8 g / h, the co-catalyst (triethylaluminum, TEA) has a flow rate of 6 g / h, the external electron donor (diisopropyldimethoxysilane, DIPDMS) has a flow rate of 0.8 g / h, and the propylene has a flow rate of 10 kg / h. After the prepolymerization reaction, the mixture enters the first tubular reactor 1 through the catalyst feed line 104. Propylene enters the first tubular reactor 1 at a flow rate of 50 kg / h through the first propylene feed line 105. Specific process conditions are shown in Table 1.

[0096] The discharge from the first tubular reactor 1 is achieved through the discharge line 106, the first three-way valve 108, and the transmission line 206. The speed of the slurry circulation pump 101 is controlled to maintain a slurry flow velocity V1 of 7 m / s.

[0097] In the first tubular reactor 1, the reactor operating temperature is 70℃, the operating pressure is 4.0 MPa (g), and the density is 500 kg / m³. 3 (Polymer content approximately 35% wt), residence time approximately 1.25 h, calculated load P1 approximately 20.9 kg / h.

[0098] The discharge from the second tubular reactor 2 adopts the discharge method of the second tubular reactor 1# discharge line 205 and the second three-way valve 208. The speed of the slurry circulation pump 201 is controlled to keep the slurry flow velocity V2 at 7m / s.

[0099] Propylene enters the second tubular reactor 2 at a flow rate of 40 kg / h through the second propylene feed line 204. The reactor operating temperature is 70℃, the operating pressure is 4.0 MPa (g), and the density is 510 kg / m³. 3(Polymer content approximately 38% wt), residence time approximately 0.76 h, calculated load P2 approximately 16.8 kg / h.

[0100] Example 3

[0101] Same as Example 2, but with the following differences.

[0102] Adjust the speed of the slurry circulation pump 101 to make the slurry flow velocity V1 10 m / s. At this time, the density of the first tubular reactor 1 is 480 kg / m³. 3 (Polymer content approximately 29% wt), residence time approximately 1.2 h, calculated load P1 approximately 17.2 kg / h.

[0103] The second tubular reactor 2 has a density of 505 kg / m³. 3 (Polymer content approximately 36% wt), residence time approximately 0.76 h, calculated load P2 approximately 19.1 kg / h.

[0104] Example 4

[0105] Same as Example 2, but with the following differences.

[0106] The ratio of the slurry guide vane pitch L14 to the guide vane component inner diameter D11 in guide vane component 103 is adjusted to 2. At this time, the density of the first tubular reactor 1 is 510 kg / m³. 3 (Polymer content approximately 38% wt), residence time approximately 1.28 h, calculated load P1 approximately 22.6 kg / h.

[0107] The second tubular reactor 2 has a density of 500 kg / m³. 3 (Polymer content approximately 35% wt), residence time approximately 0.75 h, calculated load P2 approximately 12.2 kg / h.

[0108] Example 5

[0109] Same as Example 2, except as follows.

[0110] The ratio of the slurry guide vane length L12 to the slurry guide vane pitch L14 is adjusted to 0.25. At this time, the density of the first tubular reactor 1 is 490 kg / m³. 3 (Polymer content approximately 32% wt), residence time approximately 1.23 h, calculated load P1 approximately 19.1 kg / h.

[0111] The second tubular reactor 2 has a density of 505 kg / m³. 3 (Polymer content approximately 36% wt), residence time approximately 0.76 h, calculated load P2 approximately 17.2 kg / h.

[0112] Example 6

[0113] Same as Example 2, except as follows.

[0114] Adjust the ratio of the distance L101 from the slurry outlet corresponding to the discharge line 106 of the first tubular reactor to the reactor diameter D to 1. At this time, the density of the first tubular reactor 1 is 485 kg / m³. 3 (Polymer content approximately 30% wt), residence time approximately 1.21 h, calculated load P1 approximately 18.2 kg / h.

[0115] The second tubular reactor 2 has a density of 500 kg / m³. 3 (Polymer content approximately 35% wt), residence time approximately 0.75 h, calculated load P2 approximately 16.7 kg / h.

[0116] Example 7

[0117] Same as Example 2, except as follows.

[0118] The catalyst flow rate was increased to 1.0 g / h. At this point, the density of the first tubular reactor 1 was 530 kg / m³. 3 (Polymer content approximately 43% wt), residence time approximately 1.32 h, calculated load P1 approximately 25.9 kg / h.

[0119] The density of the second tubular reactor 2 is 535 kg / m³. 3 (Polymer content approximately 44% wt), residence time approximately 0.80 h, calculated load P2 approximately 18.5 kg / h.

[0120] Example 8

[0121] Same as Example 2, except as follows.

[0122] The discharge method of the first tubular reactor 1 is adjusted to use the discharge line 107 of the first tubular reactor 2, the first three-way valve 108, and the transmission line 206. The discharge line 107 of the first tubular reactor 2 uses the existing conventional discharge method. At this time, the density of the first tubular reactor 1 is 530 kg / m³. 3 (Polymer content approximately 43% wt), residence time approximately 1.32 h, calculated load P1 approximately 25.9 kg / h. Reactor cooling jacket water flow rate is 2.0 t / h, jacket water inlet and outlet temperatures are 63.3℃ and 68.5℃ respectively, calculated heat transfer efficiency η is 77.6%.

[0123] The density of the second tubular reactor 2 is 488 kg / m³ 3 (Polymer content approximately 31% wt), residence time approximately 0.73 h, calculated load P2 approximately 5.4 kg / h.

[0124] Comparative Example 1

[0125] Same as Example 8, except as follows.

[0126] The guide vane component of the first tubular reactor 1 is replaced with a straight pipe, and the discharge method of the first tubular reactor 2# discharge line 107 and conveyor line 206 is adopted. At this time, the density of the first tubular reactor 1 is 530 kg / m³. 3 (Polymer content approximately 43% wt), residence time approximately 1.32 h, calculated load P1 approximately 25.9 kg / h. Reactor cooling jacket water flow rate is 2.0 t / h, jacket water inlet and outlet temperatures are 62.8℃ and 68.0℃ respectively, calculated heat transfer efficiency η is 72.2%.

[0127] The discharge method of the second tubular reactor 2 is adjusted to use the discharge line 207 and the second three-way valve 208. The discharge line 207 of the second tubular reactor uses the existing conventional discharge method. At this time, the density of the second tubular reactor 2 is 490 kg / m³. 3 (Polymer content approximately 32% wt), residence time approximately 0.74 h, calculated load P2 approximately 6.0 kg / h.

[0128] Example 9

[0129] Same as Example 3, except as follows.

[0130] The discharge method of the first tubular reactor 1 is adjusted to use the discharge line 107 of the first tubular reactor 2, the first three-way valve 108, and the transmission line 206. The discharge line 107 of the first tubular reactor 2 uses the existing conventional discharge method. At this time, the density of the first tubular reactor 1 is 520 kg / m³. 3 (Polymer content approximately 40% wt), residence time approximately 1.30 h, calculated load P1 approximately 24.3 kg / h.

[0131] The second tubular reactor 2 has a density of 490 kg / m³. 3 (Polymer content approximately 32% wt), residence time approximately 0.74 h, calculated load P2 approximately 7.6 kg / h.

[0132] Example 10

[0133] Same as Example 2, except as follows.

[0134] The discharge method of the first tubular reactor 1 is adjusted to use the common discharge method of discharge line 107 and discharge line 106 of the first tubular reactor 2, and discharge method of discharge line 108 and transmission line 206. The discharge method of the second tubular reactor 2 is adjusted to use discharge line 207 of the second tubular reactor 2 and discharge line 208 of the second three-way valve. The discharge pipeline of discharge line 207 of the second tubular reactor 2 adopts the existing conventional discharge method.

[0135] Under the above conditions:

[0136] The density of the first tubular reactor 1 is 515 kg / m³. 3 (Polymer content approximately 39% wt), residence time approximately 1.29 h, calculated load P1 approximately 23.5 kg / h.

[0137] The density of the second tubular reactor 2 is 508 kg / m³. 3 (Polymer content approximately 37% wt), residence time approximately 0.76 h, calculated load P2 approximately 13.7 kg / h.

[0138]

[0139] As shown in Table 1, under the same feed conditions, the method described in this invention can reduce the density of the first tubular reactor, improve heat transfer efficiency, and maintain the densities of the first and second tubular reactors at a comparable level. This means that the olefin polymerization method described in this invention can further increase the plant load (density within the reactor). Simultaneously, the method of this invention can flexibly adjust the load ratio of the first and second tubular reactors within a certain range, thereby achieving flexible control over the polymer composition.

[0140] The various embodiments of the present invention have been described above. These descriptions are exemplary and not exhaustive, nor are they limited to the disclosed embodiments. Many modifications and variations will be apparent to those skilled in the art without departing from the scope and spirit of the described embodiments.

[0141] The endpoints and any values ​​of the ranges disclosed herein are not limited to the precise ranges or values, and these ranges or values ​​should be understood to include values ​​close to these ranges or values. For numerical ranges, the endpoint values ​​of the various ranges, the endpoint values ​​of the various ranges and individual point values, and individual point values ​​can be combined with each other to obtain one or more new numerical ranges, which should be considered as specifically disclosed herein.

Claims

1. A tubular reactor, characterized in that, The reactor includes: a slurry circulation pump, a closed-loop ring pipe, a feed inlet, a slurry discharge outlet, and a guide vane assembly; the guide vane assembly is equipped with slurry guide vanes.

2. The tubular reactor according to claim 1, wherein, The slurry guide vane is an internal component with centrifugal force. Its design allows the high-speed flowing polymer slurry to achieve a centrifugal effect under its action, thereby concentrating the polymer slurry near the slurry outlet pipe wall.

3. The tubular reactor according to claim 1, wherein, In accordance with the material flow direction within the reactor, at least one slurry outlet is located adjacent to and downstream of the guide vane component.

4. The tubular reactor according to any one of claims 1-3, wherein, The slurry guide vane is in the form of a planar or curved internal component, preferably a curved internal component, and more preferably a fan blade, paddle blade, single-curved spiral blade or hyperboloid spiral blade.

5. The tubular reactor according to any one of claims 1-3, wherein, The guide vane component also includes an outer wall, which surrounds and is fixedly connected to the slurry guide vane. Preferably, the outer wall of the component is part of the ring pipe, and its two ends are connected to the rest of the ring pipe; more preferably, the two ends of the outer wall of the component are connected to the rest of the ring pipe by flanges or threads.

6. The tubular reactor according to claim 5, wherein, The slurry guide vane is connected to the outer wall of the component by a groove, thread, or welding.

7. The tubular reactor according to claim 5, wherein, The slurry guide vane is a single-curved spiral vane or a hyperbolic spiral vane; The ratio of the pitch of the slurry guide vane to the inner diameter of the guide vane component is 0.2-6, preferably 0.5-4; the ratio of the length of the slurry guide vane to the pitch is 0.05-5, preferably 0.1-3; the ratio of the length of the guide vane component to the length of the slurry guide vane is ≤2, preferably ≤1.

5.

8. The tubular reactor according to any one of claims 1-3, wherein, The guide vane component is installed in the straight section of the annular pipe; The distance between the guide vane component and the adjacent slurry outlet is ≤10m, preferably ≤5m; The ratio of the distance between the guide vane component and the adjacent slurry outlet to the diameter D of the tubular reactor is ≤10, preferably ≤5.

9. The tubular reactor according to any one of claims 1-3, wherein, The ratio of the length to the diameter of the tubular reactor is ≤1000, preferably ≤500; the diameter of the tubular reactor is 100-1200mm, preferably 150-1000mm.

10. The tubular reactor according to claim 3, wherein, The slurry outlet is one or more, located at one or more of the middle, lower middle and bottom parts of the tubular reactor.

11. The tubular reactor according to any one of claims 1-3, wherein, The annular pipe is equipped with a jacket for introducing a heat-relieving or heat-giving medium.

12. The tubular reactor according to any one of claims 1-3, wherein, The heat transfer efficiency of the tubular reactor is increased by at least 1%, preferably by at least 3%, compared to when no guide vane component is provided.

13. A tubular reactor system comprising at least two tubular reactors connected in series, wherein at least one tubular reactor is a tubular reactor as described in any one of claims 1-12.

14. The tubular reactor system according to claim 13, wherein, The preceding tubular reactor is directly connected to the following tubular reactor, or connected to the following tubular reactor via a connecting pipeline; the connecting pipeline is the external circulation pipeline for the slurry from one zone to another in the following tubular reactor.

15. The tubular reactor system according to claim 13, wherein, The tubular reactor system comprises two tubular reactors connected in series; In the first tubular reactor, the guide vane component is located in the straight pipe section within half of the pipeline after the outlet of the slurry circulation pump. The first tubular reactor is provided with two slurry outlets, one of which is located in the middle of the reactor and the other is located at the bottom of the reactor. In the second tubular reactor, the guide vane component is located in the straight pipe section of the latter half of the slurry circulation pump outlet pipe. The second tubular reactor is provided with two slurry outlets. The slurry outlet near the guide vane component is located in the lower middle part of the straight pipe section of the ring pipe, and the other is located at the bottom of the reactor. The first tubular reactor and the second tubular reactor are connected by a transmission line. One end of the transmission line is connected to the two slurry outlets of the first tubular reactor through a three-way valve, and the other end is connected to the feed inlet of the second tubular reactor.

16. An olefin polymerization method, wherein the method is carried out in a tubular reactor as described in any one of claims 1-12 or in a tubular reactor system as described in any one of claims 13-15.

17. The olefin polymerization method according to claim 16, wherein, The tubular reactor system includes at least two tubular reactors; the feed to the first tubular reactor includes one or more of the following: olefins, comonomers, diluents, catalysts, cocatalysts, activators, chain transfer agents, additives, antistatic agents, and co-reactants. The feed to the subsequent tubular reactor includes one or more of the following: olefins, comonomers, diluents, cocatalysts, activators, chain transfer agents, additives, antistatic agents, and co-reactants.

18. The olefin polymerization method according to claim 17, wherein, The olefin is an α-monoolefin, preferably C2 to C3. 10 At least one of the monounsaturated olefins.

19. The olefin polymerization method according to claim 16, wherein, The polymer content in each tubular reactor is 5-70 wt%, preferably 20-60 wt%.

20. The olefin polymerization method according to claim 16, wherein, The residence time of a single tubular reactor is 0.5-4 hours, preferably 0.6-3 hours.

21. The olefin polymerization method according to claim 16, wherein, The flow rate of polymer slurry in each tubular reactor may be the same or different, each being 2-15 m / s, preferably 3-12 m / s.

22. The olefin polymerization method according to claim 16, wherein, The polymerization temperature inside the tubular reactor is 20-150℃, preferably 20-110℃, and the operating pressure of the tubular reactor is 0.5-10MPa(g), preferably 1.0-8.0MPa(g).

23. The olefin polymerization method according to claim 16, wherein, The polymer slurry is discharged continuously or intermittently from the slurry outlet, preferably continuously.

24. The olefin polymerization method according to claim 16, wherein, The slurry guide vane increases the polymer concentration at the slurry outlet of the tubular reactor by 5-100%, preferably by 5-50%.

25. The olefin polymerization method according to claim 16, wherein, The polymerization method employs a series combination of two tubular reactors, with the ratio of the load P1 of the first tubular reactor to the load P2 of the second tubular reactor being 20 / 80-90 / 10, preferably 40 / 60-80 / 20.

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