External circulation heat removal type production device for preparing 4-methyl-1-pentene, production method and application

Abstract

The invention provides an external circulation heat removal type production device for preparing 4-methyl-1-pentene, a production method and application. External circulation heat removal is adopted, at least one mixer is arranged in the reactor and adopts a middle reducing design, a filter with flushing and discharging functions is arranged at an outlet of the reactor, and a catalyst enters next equipment along with a product and then is filtered, cleaned on line and replaced; the catalyst can be unloaded on line; and large-scale continuous operation of the device can be realized.

Description

Technical Field

[0001] The invention belongs to the technical field of 4-methyl-1-pentene, and specifically relates to an external circulation heat removal type production device for preparing 4-methyl-1-pentene, a production method and application. Background Art

[0002] 4-Methyl-1-pentene (4MP1) is an important branched α-olefin. As an important organic chemical raw material, it has been increasingly widely used in the synthesis of organic intermediates. On the one hand, 4-methyl-1-pentene can be used as a comonomer of high-quality linear low-density polyethylene (LLDPE). On the other hand, it can be self-polymerized into poly-4-methyl-1-pentene (PMP), which is the lowest density synthetic material known (830kg / m 3 ), and has high melting point and softening point (240℃), high transparency, good dielectric properties, and PMP can withstand the most stringent sterilization and disinfection conditions, and can be widely used in medicine. In addition, 4-methyl-1-pentene can also be used in the artificial leather industry to make high-performance leather paper. From the perspective of the international market, 4MP1 has great application prospects, and its industrial development has also attracted much attention.

[0003] Propylene dimerization to synthesize 4-methyl-1-pentene (4M1P) is an important way to achieve the rational and high-value utilization of propylene resources. 4-methyl-1-pentene is one of the comonomers of polybutene-1, and it is also an important monomer for synthesizing high-end polyolefins - poly-4-methyl-1-pentene (PMP). Therefore, this project has a strong supporting role in the abundance and adaptability of raw materials. It is also of great significance to the rational utilization of propylene resources, the upgrading of Sinopec's propylene industry chain, and the research and development and localization of high-end polyolefins PMP. However, the existing technology for continuous production of 4M1P by propylene dimerization has a short life of catalyst particles and does not flow out with the product. It needs to be stopped regularly to replace the catalyst and cannot be mass-produced; the reactor adopts a series of reactors, and the reactor outlet needs to be specially designed, resulting in high cost of the reactor; the reactor jacket is used to remove heat, which is only suitable for small-scale production; the heat release in large-scale production is large, and the use of an external jacket to remove heat cannot meet the process requirements. Summary of the invention

[0004] In order to solve the problems existing in the prior art, the present invention provides an external circulation heat removal production device for preparing 4-methyl-1-pentene, wherein a filter with flushing and unloading functions is arranged at the outlet of the reactor, and the filter is designed to be disassembled online. At the same time, a mixer with an axial middle diameter reduction is built into the reactor, and the reactor can be used for large-scale continuous production of 4-methyl-1-pentene by propylene dimerization.

[0005] One of the purposes of the present invention is to provide an external circulation heat removal production device for preparing 4-methyl-1-pentene, comprising: a reactor, a heat exchanger and a filtering unit and a connecting pipeline connected in sequence, wherein at least one mixer is built in the reactor, and the mixer is a columnar structure with an axial middle diameter reduction.

[0006] According to the present invention, in the production device:

[0007] The side wall shape of the central longitudinal section of the mixer is an arc, and the arc is bent toward the inner side of the mixer; preferably, the arc is a circular arc, and is vertically symmetrical with the horizontal ring line at the center of the mixer as the axis; more preferably, the radius of the circular arc is 1 to 5 times the diameter of the mixer inlet pipeline, preferably 2 to 3 times;

[0008] The mixer is vertically fixed at the center line of the reactor; a circulating material inlet is arranged at the top of the mixer, and is connected to the circulating material inlet at the top of the reactor by a pipeline;

[0009] At least two openings are evenly distributed on the horizontal ring line at the center of the mixer side wall. Preferably, 2 to 4 openings are evenly distributed. The diameter of the opening is 1 / 4 to 2 / 3 of the diameter of the mixer material inlet pipeline.

[0010] According to the present invention, when the circulating material is a gaseous component, a mixer is arranged in the reactor, and the mixer is arranged above the liquid level of the reactor; or, when the circulating material is a liquid component, a mixer is arranged in the reactor, and the mixer is arranged below the liquid level of the reactor; or, when the circulating material is a gas-liquid mixture, two mixers are vertically arranged in the reactor, and the two mixers are fixedly connected along the axial direction, one mixer is arranged above the liquid level of the reactor, and a material outlet is arranged at the bottom thereof, which is connected to the circulating material inlet pipeline at the top of the other mixer; the other mixer is arranged below the liquid level of the reactor.

[0011] According to the present invention, in the production device:

[0012] The reactor is provided with a circulating material inlet at the top and a material outlet at the bottom, which are respectively connected to the top material outlet and the bottom material inlet of the heat exchanger through pipelines to form an external circulation heat removal system;

[0013] The reactor side line is provided with a raw material inlet;

[0014] The bottom material inlet and the top material outlet of the heat exchanger are provided with baffles along the outer periphery of the outermost heat exchange tube; the baffles are provided at both ends of the heat exchange tube, and the shape of the baffles is not particularly limited, and can be conical, arc-shaped, etc., and its function is to guide all the materials into the heat exchanger for heat exchange;

[0015] A circulating pump is arranged on the pipeline between the material outlet at the bottom of the reactor and the material inlet at the bottom of the heat exchanger.

[0016] According to the present invention, in the production device, the filtration unit includes at least two parallel filters and a safety filter C connected in series therewith. Preferably, the filtration unit includes two parallel filters A and filter B. The filter A and / or filter B are closed filters or open filters. The filter A and filter B are also connected to a flushing device and a pressure relief device. When the filter A and / or filter B adopt an open filter, the open filter device commonly used in the art can be used. Specifically, a quick-opening bottom cover linked to an opening cover arm is provided at the bottom of the open filter. When unloading is required, the quick-opening bottom cover is opened by the opening cover arm to perform unloading operations. When the filter A and / or filter B adopts a closed filter, the closed filter device commonly used in the art can be used. Specifically, a closed design is adopted at the bottom of the closed filter, and a discharge valve is provided. When unloading is required, the discharge valve can be opened to perform unloading operations.

[0017] The present invention adopts at least two filters A and filter B designed in parallel, and can realize online disassembly. When filter A is blocked, filter A is shut down, filter B is switched on, the pressure relief valve is opened, and the pressure of filter A is relieved. After the pressure relief is completed, the flushing pipeline is opened to flush filter A. The flushed filter A is reserved for use. When filter B is blocked, filter B is shut down, filter A is switched on, filter B is shut down, and the above pressure relief and flushing operation steps are repeated.

[0018] The second object of the present invention is to provide a production method for preparing 4-methyl-1-pentene, by adopting the above-mentioned external circulation heat removal production device to prepare 4-methyl-1-pentene.

[0019] According to the present invention, the production method comprises the following steps:

[0020] (1) feeding propylene, solvent and catalyst into a reactor through a raw material inlet of the reactor and heating to carry out a polymerization reaction;

[0021] (2) The material after the polymerization reaction is divided into two parts. One part of the material is filtered by the filtration unit and then enters the separation unit for separation and purification. The other part of the material is cooled by the heat exchanger and then enters the mixer in the reactor. The material in the mixer is mixed with the raw material entering the reactor and then continues the polymerization reaction.

[0022] According to the present invention, in the production method, the solvent and catalyst can be solvents commonly used in the preparation technology of 4-methyl-1-pentene, for example, the solvent can be at least one of dodecane, heptane, pentane and toluene, preferably dodecane, and the catalyst can be an alkali metal element, an alkali metal carbonate or an alkali metal bicarbonate catalyst system or a uranium or rare earth metal bis-(polysubstituted cyclopentadiene)-hydride complex, such as a supported K-Fe / K 2 CO 3 catalyst.

[0023] According to the present invention, the propylene, solvent and catalyst used in the preparation of 4-methyl-1-pentene can be added according to the commonly used amounts in the prior art, for example, the mass ratio of propylene to solvent is 1:(0.5-2); the amount of catalyst used is 2-20wt% of propylene.

[0024] According to the present invention, in the production method:

[0025] The operating conditions of the reactor are: the reaction is carried out under a protective gas atmosphere (such as nitrogen), the operating temperature is 150-200°C, and the operating pressure is 4.5-8MPaG;

[0026] The operating conditions of the heat exchanger are: the material outlet temperature is 140-200°C, the material inlet temperature is 5-10°C higher than the outlet; the material outlet operating pressure is 4.5-8MPaG, the material inlet operating pressure is 0.5-1MPaG higher than the outlet; the refrigerant inlet temperature is 5-10°C lower than the material outlet temperature, and the refrigerant inlet pressure is 0.05-0.15MPaG higher than the outlet pressure;

[0027] The operating conditions of the filter are: operating temperature of 150-200° C., operating pressure of 5.5-9 MPaG, and filtration accuracy of 5-30 μm.

[0028] According to the present invention, the material filtered by the filtering unit in step (2) accounts for 80-95% of the total amount of the material after the polymerization reaction, preferably 85-90%.

[0029] According to the present invention, in the step (2), at least one of the parallel filters of the filtration unit is a spare filter, preferably two parallel filters, one on and one off, and a more preferred switching operation is: the material is first filtered in filter A, when filter A is blocked, filter A is shut down, filter B is switched on, the pressure relief valve is opened, and the pressure of filter A is relieved. After the pressure relief is completed, the flushing pipeline is opened and filter A is flushed. The flushed filter A is kept on standby, and when filter B is blocked, the above switching, pressure relief and flushing operations are repeated.

[0030] The third object of the present invention is to provide an external circulation heat removal production device for preparing 4-methyl-1-pentene or the above-mentioned production method for preparing 4-methyl-1-pentene, and its application in the production of 4-methyl-1-pentene.

[0031] The invention adopts an external circulation heat removal production device to synthesize branched alpha-olefins through propylene dimerization technology, which can be used not only as a comonomer of linear low-density polyethylene, but also for preparing a novel thermoplastic resin PMP.

[0032] Compared with the prior art, the technical advantages of the present invention are:

[0033] 1) Continuity: The catalyst is filtered after entering the next equipment along with the product, and can be cleaned and replaced online; the catalyst can be unloaded online; and the device can be operated continuously on a large scale.

[0034] 2) Flexibility:

[0035] A) It overcomes the problem of short catalyst life and catalyst online unloading affecting production scale;

[0036] B) Using external circulation to remove heat is also applicable to large-scale production;

[0037] C) A mixer with a specific structure is built into the reactor to ensure uniform mixing of fresh supplementary materials and products;

[0038] 3) Economical: The reactor does not need to be equipped with special filtering internals.

[0039] The production device provided by the present invention is conducive to increasing the technical accumulation in the direction of olefin oligomerization and achieving a breakthrough in functional monomer technology. At the same time, the present invention adopts an external circulation heat removal device to achieve continuous propylene dimerization reaction, which is expected to fill the gap in the domestic production technology of propylene dimerization to 4-methyl-1-pentene and provide sufficient raw materials for the production of PMP, which is of great significance. BRIEF DESCRIPTION OF THE DRAWINGS

[0040] Figure 1 This is a schematic diagram of a production device used in an embodiment of the present invention. Figure 1 In the figure, A-mixer A, B-mixer B, 1-raw material inlet logistics, 2-kettle reactor, 3-reactor outlet logistics, 4-circulation pump, 5-circulation pump outlet logistics, 6-heat exchanger, 7-heat exchanger outlet logistics, 8-heat exchanger flushing pipeline, 9-filter inlet logistics, 10-filter A, 10′-filter B, 11-filter outlet logistics, 12-security filter, 13-security filter outlet logistics, 14-mixer A circulating material inlet, 15-mixer A opening, 16-mixer B circulating material inlet, 17-mixer B opening, 18-heat exchanger baffle, 19-flushing device, 20-pressure relief device.

[0041] Figure 2 This is a schematic diagram of a quick-open filter used in an embodiment of the present invention. Figure 2 In the figure, 9-filter inlet logistics, 11-filter outlet logistics, 19-flushing device, 20-pressure relief device, 21-quick-open bottom cover, 22-opening cover arm.

[0042] Figure 3 This is a schematic diagram of a closed filter used in an embodiment of the present invention. Figure 3 Among them, 9-filter inlet logistics, 11-filter outlet logistics, 19-flushing device, 20-pressure relief device, 23-unloading valve, 24-unloading logistics.

[0043] Figure 4 It is a schematic diagram of a production device in the prior art. DETAILED DESCRIPTION

[0044] In order to solve the problems existing in the prior art, the present invention provides a production device for preparing 4-methyl-1-pentene by external circulation heat removal, comprising: a reactor 2, a heat exchanger 6, a filtering unit and a connecting pipeline, wherein at least one mixer is built in the reactor, and the mixer is a columnar structure with an axial middle diameter reduction.

[0045] According to the present invention, in the production device:

[0046] The side wall of the mixer is an arc structure, and the arc structure is bent toward the inner side of the mixer; preferably, the radius of the arc structure is 1 to 5 times, preferably 2 to 3 times, the diameter of the mixer inlet pipeline;

[0047] The mixer is vertically fixed on the center line of the reactor; a circulating material inlet is arranged on the top of the mixer and is connected to the circulating material inlet on the top of the reactor by a pipeline;

[0048] At least two openings are evenly distributed on the central ring line of the mixer side wall, preferably, 2 to 4 openings are evenly distributed, and the diameter of the opening is 1 / 4 to 2 / 3 of the diameter of the mixer material inlet pipeline.

[0049] According to the present invention, when the circulating material is a gaseous component, a mixer A is arranged in the reactor, and the mixer A is arranged above the liquid level of the reactor; or, when the circulating material is a liquid component, a mixer B is arranged in the reactor, and the mixer B is arranged below the liquid level of the reactor; or, when the circulating material is a gas-liquid mixture, two mixers A and B vertically connected by pipelines are arranged in the reactor, the two mixers A and B are fixedly connected along the axial direction, the mixer A is arranged above the liquid level of the reactor, and the mixer B is arranged below the liquid level of the reactor.

[0050] According to the present invention, in the production device:

[0051] The reactor 2 is provided with a circulating material inlet at the top and a material outlet at the bottom, which are respectively connected to the top and bottom of the heat exchanger through pipelines to form an external circulation heat removal system;

[0052] The reactor side line is provided with a raw material inlet 1;

[0053] The inlet and outlet of the heat exchanger are provided with baffles 18 along the outer diameter of the outermost heat exchange tube;

[0054] A circulation pump 4 is arranged on the pipeline between the material outlet at the bottom of the reactor and the material inlet at the bottom of the heat exchanger.

[0055] According to the present invention, in the production device, the filtration unit includes at least two parallel filters A10 and filter B10', and a safety filter C12 connected in series. Preferably, the filter A10 and / or filter B10' are closed filters or open filters, and the filter 10 and filter B10' are also connected to a flushing device 19 and a pressure relief device 20. When the filter A10 and / or filter B10' adopts an open filter, the open filter equipment commonly used in the art can be used, specifically, such as Figure 2 As shown, a quick-open bottom cover 21 linked to a cover opening arm 22 is provided at the bottom of the open filter. When unloading is required, the quick-open bottom cover 21 is opened by the cover opening arm 22 to perform unloading operation. When the filter A10 and / or the filter B10′ adopts a closed filter, a closed filter device commonly used in the art can be adopted, specifically, as Figure 3 As shown, a closed design is adopted at the bottom of the closed filter, and a discharge valve 23 is provided. When unloading is required, the discharge valve 23 can be opened to perform the unloading operation and discharge the unloading flow 24 out of the system.

[0056] The present invention adopts at least two filters A and filter B designed in parallel, and can realize online disassembly. When filter A is blocked, filter A is shut down, filter B is switched on, the pressure relief valve is opened, and the pressure of filter A is relieved. After the pressure relief is completed, the flushing pipeline is opened to flush filter A. The flushed filter A is reserved for use. When filter B is blocked, filter B is shut down, filter A is switched on, filter B is shut down, and the above pressure relief and flushing operation steps are repeated.

[0057] The present invention is described in detail below in conjunction with specific embodiments. It is necessary to point out that the following embodiments are only used to further illustrate the present invention and cannot be understood as limiting the scope of protection of the present invention. Some non-essential improvements and adjustments made to the present invention by those skilled in the art based on the contents of the present invention still fall within the scope of protection of the present invention.

[0058] The raw materials used in the examples and comparative examples, unless otherwise specified, are disclosed in the prior art, for example, they can be directly purchased or prepared according to the preparation methods disclosed in the prior art.

[0059] Example 1

[0060] Combine the following Figure 1 The production device and production method for continuously preparing 4-methyl-1-pentene provided by the present invention are described.

[0061] like Figure 1 As shown, the production device for continuously preparing 4-methyl-1-pentene includes: a kettle reactor 2, a heat exchanger 6, a filtering unit and a connecting pipeline. A raw material inlet 1 is arranged on the side line of the kettle reactor 2, a circulating material inlet is arranged on the top of the kettle reactor 2, and a material outlet is arranged on the bottom, which are respectively connected to the top and bottom of the heat exchanger through pipelines to form an external circulation heat removal system. The kettle reactor 2 has a built-in mixer A and a mixer B, and the mixer A and the mixer B are cylindrical structures with axial middle diameter reduction. The side walls of the mixer A and the mixer B are arc structures, and the arc structures are bent toward the inner side of the mixer; the mixer A and the mixer B are vertically fixed on the center line of the reactor; a circulating material inlet is arranged on the top of the mixer A, and the circulating material inlet on the top of the kettle reactor 2 is connected by a pipeline. The mixer A is arranged above the liquid level of the kettle reactor 2, and the mixer B is arranged below the liquid level of the kettle reactor 2. The inlet and outlet of the heat exchanger 6 are provided with baffles 18 along the outer diameter of the outermost heat exchange tube, and the outlet of the heat exchanger 6 is also provided with a heat exchanger flushing pipeline 8. A circulating pump 4 is arranged on the pipeline between the bottom material outlet of the kettle reactor 2 and the bottom material inlet of the heat exchanger. The reactor outlet logistics 3 is divided into two parts by the circulating pump 4. One part of the logistics 9 (filter inlet logistics) is sent to the filtering unit, and the remaining material is sent to the heat exchanger 6. The outlet logistics 7 after heat exchange in the heat exchanger 6 is sent to the mixer in the reactor 2. The filtering unit includes two parallel filters A10 and filter B10', and a security filter 12 connected in series. The filter A10 and filter B10' are closed filters. The filter A10 and filter B10' are also provided with a flushing device 19 and a pressure relief device 20. The present invention adopts the parallel design of the filter A10 and filter B10', which can realize online disassembly. The outlet logistics 11 after filtration by the filter A10 or the filter B10' enters the security filter 12 for further filtration, and the outlet logistics 13 obtained enters the subsequent separation operation to obtain the 4-methyl-1-pentene product.

[0062] In the above production device, the radius of the arc structure of the side wall of mixer A and B is 1 / 2 of the diameter of the mixer inlet pipeline, and 4 openings are evenly distributed at the center ring lines 15 and 17 of the side wall of mixer A and B, and the diameter of the opening is 1 / 5 of the diameter of the pipeline at the mixer material inlet 14 or 16. The fresh raw material inlet 1 entering the reactor is on the same horizontal line as the opening position 17 of mixer B.

[0063] Taking the annual production of 10,000 tons of 4M1P products as an example, the above Figure 1 The production device specifically describes a method for continuously preparing 4-methyl-1-pentene, comprising:

[0064] Fresh propylene, solvent (dodecane), catalyst (supported K-Fe / K 2 CO 3 The mixture was heated to 145°C and then sent to reactor 2 for polymerization. Under nitrogen atmosphere, the reactor was operated at 145°C, 5MPaG, and a space velocity of 1h -1 . Among them, the propylene feed rate is 3t / h, the solvent feed rate is 4.5t / h, and the catalyst feed rate is 500t / a. The operating conditions of the heat exchanger are: material inlet temperature 155℃, material outlet temperature 145℃; material inlet operating pressure 6.5MPaG, material outlet operating pressure 6.0MPaG; refrigerant inlet temperature 140℃, refrigerant outlet temperature 150℃, refrigerant inlet pressure 0.55MPaG, refrigerant outlet pressure 0.45MPaG.

[0065] The materials after polymerization reaction in reactor 2 are sent to filter A10 through circulation pump 4, and part of the materials (accounting for 90% of the materials at the outlet of the circulation pump) are sent to filter A10 for coarse filtration. The filtered materials enter security filter 11 for filtration and are sent to separation unit for separation and purification; the remaining materials are sent to heat exchanger 6 for cooling and then sent to the built-in mixer of reactor. The operating conditions of the filter are: operating temperature is 155℃, operating pressure is 6.5MPaG, and filtration accuracy is 5μm.

[0066] In the continuous production process, the preparation method of Example 1 can achieve a propylene single-pass conversion rate of 50-80%, a polymerization product selectivity of 80-90%, a 4-methyl-1-pentene selectivity of 70-90%, and a 4-methyl-1-pentene product with a purity of 85-98%.

[0067] Example 2

[0068] The difference from the production device in Example 1 is that only a mixer B located below the liquid surface is arranged in the kettle reactor 2. The fresh raw material inlet 1 entering the reactor and the opening position 17 of the mixer B are on the same horizontal line.

[0069] The production device for continuously preparing 4-methyl-1-pentene includes: a kettle reactor 2, a heat exchanger 6, a filtering unit and a connecting pipeline. A raw material inlet 1 is arranged on the side line of the kettle reactor 2, a circulating material inlet is arranged on the top of the kettle reactor 2, and a material outlet is arranged on the bottom, which are respectively connected to the top and bottom of the heat exchanger through pipelines to form an external circulation heat removal system. The kettle reactor 2 has a built-in mixer B, and the mixer B is a columnar structure with an axial middle diameter reduction. The side wall of the mixer B is an arc structure, and the arc structure is bent toward the inner side of the mixer; the mixer B is vertically fixed on the center line of the reactor; a circulating material inlet is arranged on the top of the mixer B, and the circulating material inlet at the top of the kettle reactor 2 is connected by a pipeline. The inlet and outlet of the heat exchanger 6 are provided with baffles 18 along the outer diameter of the outermost heat exchange tube, and a heat exchanger flushing pipeline 8 is also provided at the outlet of the heat exchanger 6. A circulating pump 4 is arranged on the pipeline between the bottom material outlet of the kettle reactor 2 and the bottom material inlet of the heat exchanger. The reactor outlet logistics 3 is divided into two parts by the circulating pump 4. One part of the logistics 9 (filter inlet logistics) is sent to the filtering unit, and the remaining material is sent to the heat exchanger 6. The outlet logistics 7 after heat exchange in the heat exchanger 6 is sent to the mixer in the reactor 2. The filtering unit includes two parallel filters A10 and filter B10', and a security filter 12 connected in series. The filter A10 and filter B10' are closed filters. The filter A10 and filter B10' are also provided with a flushing device 19 and a pressure relief device 20. The present invention adopts the parallel design of the filter A10 and filter B10', which can realize online disassembly. The outlet logistics 11 after filtration by the filter A10 or the filter B10' enters the security filter 12 for further filtration, and the outlet logistics 13 obtained enters the subsequent separation operation to obtain the 4-methyl-1-pentene product.

[0070] In the above production device, the radius of the arc structure of the side wall B is 1 / 2 of the diameter of the mixer inlet pipeline, and 4 openings are evenly distributed at the center ring line 17 of the side wall of the mixer B, and the diameter of the opening is 1 / 5 of the diameter of the pipeline at the mixer material inlet 16. The fresh raw material inlet 1 entering the reactor is on the same horizontal line as the opening position 17 of the mixer B.

[0071] Taking the annual production of 10,000 tons of 4M1P products as an example, the above production device is used to specifically illustrate the production method for continuously preparing 4-methyl-1-pentene, including:

[0072] Fresh propylene, solvent (dodecane), catalyst (supported K-Fe / K 2 CO 3 The mixture was heated to 140°C and then sent to reactor 2 for polymerization. Under nitrogen atmosphere, the reactor was operated at 140°C, 5 MPaG, and a space velocity of 1 h -1. Among them, the propylene feed rate is 3t / h, the solvent feed rate is 4.5t / h, and the catalyst feed rate is 500t / a. The operating conditions of the heat exchanger are: material inlet temperature 150℃, material outlet temperature 140℃; material inlet operating pressure 6.5MPaG, material outlet operating pressure 6.0MPaG; refrigerant inlet temperature 135℃, refrigerant outlet temperature 145℃, refrigerant inlet pressure 0.55MPaG, refrigerant outlet pressure 0.45MPaG.

[0073] The materials after polymerization reaction in reactor 2 are sent to filter A10 through circulation pump 4, and part of the materials (accounting for 90% of the materials at the outlet of the circulation pump) are sent to filter A10 for coarse filtration. The filtered materials enter security filter 11 for filtration and are sent to separation unit for separation and purification; the remaining materials are sent to heat exchanger 6 for cooling and then sent to the mixer built in reactor. The operating conditions of the filter are: operating temperature is 150℃, operating pressure is 6.5MPaG, and filtration accuracy is 5μm.

[0074] In the continuous production process, the preparation method of Example 2 can achieve a propylene single-pass conversion rate of 60-80%, a polymerization product selectivity of 85-90%, a 4-methyl-1-pentene selectivity of 80-90%, and a 4-methyl-1-pentene product with a purity of 90-98%.

[0075] Comparative Example 1

[0076] use Figure 4 4MP1 was prepared as comparative example 1 using a device, wherein the reactor used was a two-stage series-connected jacketed kettle reactor, and the specific preparation method included:

[0077] Fresh propylene is sent to the deoxygenation and dehydration dryer for pretreatment at room temperature and operating pressure of 3MPaG. The raw propylene after deoxygenation and dehydration is heated to 140℃ under the action of the preheater and then sent to the first polymerization reactor. With solid base catalyst, the operating temperature of the first polymerization reactor is 140℃ and the operating pressure is 5MPaG; the product after the reaction of the first polymerization reactor enters the second polymerization reactor by overflow. The second polymerization reactor is subjected to the conditions of operating temperature of 150℃ and operating pressure of 5MPaG, and the product after the reaction is sent to the separation unit after passing through the filter. Among them, the flow rate of fresh propylene is 320kg / h, and the flow rate of solvent dodecane is 960kg / h.

[0078] The preparation method of Comparative Example 1 can achieve a propylene single-pass conversion rate of 45%, a dimerization product selectivity of >75%, a 4-methyl-1-pentene selectivity of more than 70%, and obtain a 4-methyl-1-pentene product with a purity greater than 97.5%. However, in the continuous production process, the catalyst needs to be stopped and replaced regularly, and long-term continuous production cannot be achieved.

Claims

1. An external circulation heat removal production device for preparing 4-methyl-1-pentene, include: A reactor, a heat exchanger, a filtering unit and a connecting pipeline are connected in sequence, and the reactor has at least one mixer built therein, and the mixer is a columnar structure with an axially reduced diameter in the middle.

2. The production device according to claim 1, It is characterized in that The side wall shape of the central longitudinal section of the mixer is an arc, and the arc is bent toward the inner side of the mixer; preferably, the arc is a circular arc, and is symmetrical up and down with the horizontal ring line of the center of the mixer as the axis; more preferably, the radius of the circular arc is 1 to 5 times, preferably 2 to 3 times, the diameter of the mixer inlet pipeline; and / or, The mixer is fixed vertically at the center line of the reactor; and / or, a circulating material inlet is arranged at the top of the mixer, and is connected to the circulating material inlet at the top of the reactor by a pipeline; and / or, At least two openings are evenly distributed on the horizontal ring line at the center of the mixer side wall, preferably, 2 to 4 openings are evenly distributed, and / or the diameter of the opening is 1 / 4 to 2 / 3 of the diameter of the mixer material inlet pipeline.

3. The production device according to claim 1 or 2, It is characterized in that When the circulating material is a gas phase component, a mixer is provided in the reactor, and the mixer is provided above the liquid level of the reactor; or, When the circulating material is a liquid component, a mixer is provided in the reactor, and the mixer is provided below the liquid level of the reactor; or, When the circulating material is a gas-liquid mixture, two mixers are vertically arranged in the reactor and are fixedly connected along the axial direction. One mixer is arranged above the liquid level of the reactor, and a material outlet is arranged at its bottom and is connected to the circulating material inlet pipeline at the top of the other mixer; the other mixer is arranged below the liquid level of the reactor.

4. The production device according to claim 1, It is characterized in that The reactor is provided with a circulating material inlet at the top and a material outlet at the bottom, which are respectively connected to the top material outlet and the bottom material inlet of the heat exchanger through pipelines to form an external circulation heat removal system; and / or, The reactor side line is provided with a raw material inlet; and / or, The bottom material inlet and the top material outlet of the heat exchanger are provided with baffles along the periphery of the outermost heat exchange tube; and / or, A circulating pump is arranged on the pipeline between the material outlet at the bottom of the reactor and the material inlet at the bottom of the heat exchanger.

5. The production device according to claim 1, It is characterized in that The filtering unit includes at least two parallel filters and a safety filter C connected in series. Preferably, the filtering unit includes two parallel filters A and filter B, and the filter A and / or filter B are closed filters or open filters; and / or the filter A and filter B are also connected to a flushing device and a pressure relief device.

6. A method for preparing 4-methyl-1-pentene, comprising preparing 4-methyl-1-pentene by using the external circulation heat removal production device according to any one of claims 1 to 5.

7. The production method according to claim 6, It is characterized in that The following steps are involved: (1) feeding propylene, solvent and catalyst into a reactor through a raw material inlet of the reactor and heating to carry out a polymerization reaction; (2) The material after the polymerization reaction is divided into two parts. One part of the material is filtered by the filtration unit and then enters the separation unit for separation and purification. The other part of the material is cooled by the heat exchanger and then enters the mixer in the reactor. The material in the mixer is mixed with the raw material entering the reactor and then continues the polymerization reaction.

8. The production method according to claim 7, It is characterized in that The operating conditions of the reactor are: the reaction is carried out under a protective gas atmosphere, the operating temperature is 150-200°C, and the operating pressure is 4.5-8MPaG; and / or, The operating conditions of the heat exchanger are: the material outlet temperature is 140-200°C, the material inlet temperature is 5-10°C higher than the outlet; the material outlet operating pressure is 4.5-8MPaG, the material inlet operating pressure is 0.5-1MPaG higher than the outlet; the refrigerant inlet temperature is 5-10°C lower than the material outlet temperature, and the refrigerant inlet pressure is 0.05-0.15MPaG higher than the outlet pressure; and / or, The operating conditions of the filter are: operating temperature of 150-200° C., operating pressure of 5.5-9 MPaG, and filtration accuracy of 5-30 μm.

9. The production method according to claim 7, It is characterized in that The mass ratio of propylene to solvent is 1:(0.5-2); and / or, The amount of the catalyst is 2 to 20 wt% of propylene; and / or, The material filtered through the filtering unit in step (2) accounts for 80-95% of the total amount of the material after the polymerization reaction, preferably 85-90%.

10. The production method according to claim 7, It is characterized in that At least one of the parallel filters of the filtration unit is a spare filter, preferably two parallel filters, one on and one off, and a more preferred switching operation is: the material is first filtered in filter A, when filter A is blocked, filter A is shut down, filter B is switched on, the pressure relief valve is opened, and the pressure of filter A is relieved, after the pressure relief is completed, the flushing pipeline is opened, and filter A is flushed. The flushed filter A is kept on standby, and when filter B is blocked, filter B is shut down, and the above switching, pressure relief, and flushing operations are repeated.

11. Use of an external circulation heat removal production device for preparing 4-methyl-1-pentene as claimed in any one of claims 1 to 5 or a production method for preparing 4-methyl-1-pentene as claimed in any one of claims 6 to 10 in the production of 4-methyl-1-pentene.

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