Annular tube reaction device for preparing 4-methyl-1-pentene, preparation method and application

Abstract

The invention provides a loop reaction device for preparing 4-methyl-1-pentene, a preparation method and application. The loop reactor is adopted, a material inlet and a catalyst inlet of the loop reactor are designed to be of an arc structure, a filter with flushing and discharging functions is arranged at an outlet of the reactor, and the 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 a ring tube reaction device for preparing 4-methyl-1-pentene, a preparation method and application thereof. Background Art

[0002] Propylene is an important raw material for modern chemical synthesis. 4-Methyl-1-pentene (4MP1) formed by its dimerization has important industrial application value. 6 Olefins are widely used in copolymerization to form linear low-density polyethylene resin (LLDPE). When 4MP1 is used as a comonomer, linear low-density polyethylene has higher product properties. Among them, 4MP1 has a lower cost and is receiving more and more attention.

[0003] 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. It can be self-polymerized into poly-4-methyl-1-pentene (PMP). PMP is the synthetic material with the lowest known density (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.

[0004] 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.

[0005] At present, my country's 4M1P (4-methyl-1-pentene) products are in the initial stage of the market, with great development potential, large demand for 4M1P, and broad market prospects. However, the current domestic production capacity is obviously insufficient, and 4M1P downstream products are abundant, and the market is still expanding. Although traditional solid base catalysts have been industrialized abroad and highly selective dimerization of propylene has been achieved under laboratory conditions in China, the key technology for large-scale production of 4M1P is still lacking. Therefore, domestic scholars need to design reasonable industrial processes and equipment to ensure the stable performance of the catalyst and achieve highly selective dimerization of propylene, in order to break the foreign technology monopoly. Summary of the invention

[0006] In order to solve the problems existing in the prior art, the present invention provides a ring tube reaction device for preparing 4-methyl-1-pentene.

[0007] One of the purposes of the present invention is to provide a loop tube reaction device for preparing 4-methyl-1-pentene, comprising: a loop tube reactor and a filtering unit connected in sequence, wherein the loop tube reactor is provided with a material inlet and a material outlet; wherein the loop tube at the material inlet of the loop tube reactor is provided with a concave structure, and the tube wall of the concave structure is bent toward the inner side of the loop tube; wherein the material outlet of the loop tube reactor is connected with the filtering unit through a pipeline.

[0008] According to the present invention, in the loop tube reaction device for preparing 4-methyl-1-pentene, the loop tube reactor can adopt a loop tube reactor commonly used in the prior art, such as a U-shaped tube, a square tube or an elliptical tube, and can adopt a single loop tube reactor or a multi-loop tube reactor, preferably a combination of multiple square loop tube reactors; the loop tube of the loop tube reactor is wrapped with a jacket temperature control device. In the actual production process, according to the temperature control needs in the reactor, the jacket temperature control device is wrapped around the loop tube temperature control point and an independent temperature control design is adopted. In the production process, the temperature control device is opened by monitoring the temperature at various locations in the loop tube to achieve segmented heat removal.

[0009] According to the present invention, in the annular tube reaction device for preparing 4-methyl-1-pentene, the concave surface of the concave structure of the material inlet of the annular tube reactor is an arc surface; preferably, the radius of the arc surface is 1 to 5 times the diameter of the inlet pipeline, preferably 2 to 3 times. The arc design is conducive to the material entering the reactor more easily and fully mixing with the returned masterbatch; the reactor inlet is designed to be an arc shape, where the flow rate is fast and the pressure is relatively small, and the fresh material at the inlet can be better guided, overcoming the problem that the fresh material and the masterbatch at the inlet of the ordinary annular tube reactor are not easy to mix evenly.

[0010] According to the present invention, in the loop tube reaction device for preparing 4-methyl-1-pentene, the loop tube reactor is provided with a catalyst inlet, and the loop tube at the catalyst inlet is provided with a concave structure, and the tube wall of the concave structure is bent toward the inner side of the loop tube; preferably, the concave surface of the concave structure of the catalyst inlet of the loop tube reactor is an arc surface; more preferably, the radius of the arc surface is 1 to 5 times the diameter of the inlet pipeline, preferably 2 to 3 times.

[0011] According to the present invention, in the ring tube reaction device for preparing 4-methyl-1-pentene:

[0012] The loop reactor is provided with an axial flow pump for controlling the flow rate of the liquid in the loop reactor;

[0013] A filter D is provided at the material outlet of the loop reactor, preferably a Johnson net filter, and more preferably, the filtering accuracy of the Johnson net filter is 5 to 50 μm.

[0014] According to the present invention, in the ring tube reaction device for preparing 4-methyl-1-pentene:

[0015] The filter unit includes at least two parallel filters and a safety filter C connected in series therewith. Preferably, the filter 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 equipment commonly used in the art can be used. Specifically, a quick-opening bottom cover linked to an opening arm is provided at the bottom of the open filter. When unloading is required, the quick-opening bottom cover is opened by the opening arm to perform unloading operations; when the filter A and / or filter B adopt a closed filter, the closed filter equipment 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.

[0016] 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.

[0017] The second object of the present invention is to provide a method for preparing 4-methyl-1-pentene, by adopting the above-mentioned ring tube reaction device to prepare 4-methyl-1-pentene.

[0018] According to the present invention, the preparation method of 4-methyl-1-pentene comprises: feeding propylene, solvent and catalyst into a loop reactor, heating to carry out polymerization reaction, filtering the material after the polymerization reaction through a filtering unit and then entering a separation unit for separation and purification.

[0019] According to an embodiment of the present invention, in the method for preparing 4-methyl-1-pentene, 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 di-(polysubstituted cyclopentadiene)-hydride complex, for example, a supported K-Fe / K 2 CO 3 catalyst.

[0020] According to an embodiment of the present invention, in the method for preparing 4-methyl-1-pentene:

[0021] The operating conditions of the loop reactor are: the reaction is carried out under a protective gas atmosphere (such as nitrogen); the temperature is 150-200°C, the liquid flow rate is 1-8m / s, and the average liquid residence time is 2-10h;

[0022] In the filtration unit, the operating conditions of filter A and filter B are: temperature of 150-200° C., pressure of 5.5-9 MPaG, and filtration accuracy of 5-30 μm.

[0023] According to an embodiment of the present invention, in the method for preparing 4-methyl-1-pentene:

[0024] 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.

[0025] A third object of the present invention is to provide an application of the above-mentioned ring tube reaction device for preparing 4-methyl-1-pentene or the above-mentioned method for preparing 4-methyl-1-pentene in the production of 4-methyl-1-pentene.

[0026] The present invention utilizes China's abundant olefin resources and synthesizes branched α-olefins through propylene dimerization technology, which can not only be used as comonomers of linear low-density polyethylene, but also can be self-polymerized to prepare new thermoplastic resin PMP. 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 realizes the continuous propylene dimerization reaction, which is expected to fill the gap in the domestic production technology of propylene dimerization to produce 4-methyl-1-pentene, and provide sufficient raw materials for the production of PMP, which is of great significance.

[0027] Compared with the prior art, the technical advantages of the present invention are:

[0028] (1) The present invention adopts a loop reactor to improve the utilization rate of the catalyst and improve production efficiency;

[0029] (2) The present invention provides independent temperature control devices on the periphery of the four-sided annular tube, so as to realize the segmented heat removal of the materials in the annular tube reactor;

[0030] (3) The present invention only adopts the design of loop reactor and filter, which reduces equipment investment;

[0031] (4) The present invention adopts a parallel filter design, which can unload and flush online, thereby realizing large-scale continuous operation of the device. BRIEF DESCRIPTION OF THE DRAWINGS

[0032] Figure 1 This is a schematic diagram of a production device used in an embodiment of the present invention. Figure 1 In the figure, 1-material inlet, 2-catalyst feed logistics, 3-catalyst inlet, 4-reactor outer jacket temperature control device, 5-reactor outlet filter net, 6-heat exchange medium temperature control device, 7-axial flow pump, 8-reactor outlet logistics, 9-filter A, 9′-filter B, 10-security filter inlet logistics; 11-security filter, 12-security filter outlet logistics, 13-heat exchange medium outlet in heat exchanger, 14-flushing device, 15-pressure relief device.

[0033] Figure 2 This is a schematic diagram of an open filter used in an embodiment of the present invention. Figure 2 In the figure, 8-filter inlet logistics, 10-filter outlet logistics, 14-flushing device, 15-pressure relief device, 16-quick-open bottom cover, 17-opening cover arm.

[0034] Figure 3 This is a schematic diagram of a closed filter used in an embodiment of the present invention. Figure 3 In the figure, 8-filter inlet logistics, 10-filter outlet logistics, 14-flushing device, 15-pressure relief device, 18-discharge valve, 19-discharge logistics.

[0035] Figure 4It is a schematic diagram of a production device in the prior art. DETAILED DESCRIPTION

[0036] In order to solve the problems existing in the prior art, a ring tube reaction device for preparing 4-methyl-1-pentene is provided, comprising: a ring tube reactor and a filtering unit connected by a pipeline, wherein the material inlet of the ring tube reactor is arranged as an arc structure, and the arc structure is bent toward the inner side.

[0037] According to the present invention, in the loop tube reaction device for preparing 4-methyl-1-pentene, the loop tube reactor can adopt a loop tube reactor commonly used in the prior art, such as a U-shaped tube, a square tube or an elliptical tube, preferably a combination of multiple square tubes; the loop tube of the loop tube reactor is wrapped with a jacket temperature control device. In the actual production process, according to the temperature control needs in the reactor, the jacket temperature control device is wrapped around the loop tube temperature control point and an independent temperature control design is adopted. In the production process, the temperature control device is turned on by monitoring the temperature at various locations in the loop tube to achieve segmented heat removal.

[0038] According to the present invention, in the loop tube reaction device for preparing 4-methyl-1-pentene, the radius of the circular arc of the material inlet of the loop tube reactor is 1 to 5 times, preferably 2 to 3 times, the diameter of the inlet pipeline.

[0039] According to the present invention, in the loop tube reaction device for preparing 4-methyl-1-pentene, the loop tube reactor is also provided with a catalyst inlet; the catalyst inlet of the loop tube reactor is arranged as an arc structure, and the arc structure is bent toward the inner side; preferably, the radius of the arc of the catalyst inlet of the loop tube reactor is 1 to 5 times the diameter of the inlet pipeline, preferably 2 to 3 times.

[0040] According to the present invention, in the ring tube reaction device for preparing 4-methyl-1-pentene:

[0041] The loop reactor is provided with an axial flow pump for controlling the flow rate of the liquid in the loop reactor;

[0042] A filter D is provided at the material outlet of the loop reactor, preferably a Johnson mesh filter.

[0043] According to the present invention, in the ring tube reaction device for preparing 4-methyl-1-pentene:

[0044] The filter unit includes at least two parallel filters A and filter B, and a safety filter C connected in series. Preferably, the filter A and / or filter B are closed filters or open filters, and 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 adopts an open filter, the open filter equipment commonly used in the art can be used. Specifically, a quick-open bottom cover linked to an opening cover arm is provided at the bottom of the open filter. When unloading is required, the quick-open 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 equipment 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.

[0045] 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.

[0046] 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.

[0047] 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.

[0048] Example 1

[0049] Combine the following Figure 1 The invention discloses a ring tube reaction device for preparing 4-methyl-1-pentene and a method for preparing 4-methyl-1-pentene.

[0050] like Figure 1As shown, the annular tube reaction device for preparing 4-methyl-1-pentene includes: an annular tube reactor and a filtering unit connected by pipelines, and the material inlet 1 of the annular tube reactor is set to a circular arc structure, and the circular arc structure is bent toward the inner side. The annular tube in the annular tube reactor is preferably a combination of multiple square tubes, and the outer temperature control points of the surrounding annular tubes are wrapped with a jacket temperature control device 4. The catalyst inlet 3 of the annular tube reactor is set to a circular arc structure, and the circular arc structure is bent toward the inner side. The annular tube reactor is provided with an axial flow pump 4, and the material outlet of the annular tube reactor is provided with a filter 5. The filtering unit includes two parallel filters A 9 and filter B 9', and a security filter C11 connected in series. The present invention adopts parallel design filters A 9 and filter B 9', which can realize online disassembly. Filter A 9 and filter B 9' adopt Figure 2 The open filter shown in the figure. Wherein, the radius of the circular arc of the material inlet of the annular tube reactor is 1 / 3 times the diameter of the inlet pipeline, and the radius of the circular arc of the catalyst inlet is 1 / 3 times the diameter of the inlet pipeline.

[0051] Preparation method of 4-methyl-1-pentene:

[0052] Using the above Figure 1 production equipment and Figure 2 The open filter is used to continuously prepare 4-methyl-1-pentene (4M1P). Taking the annual production of 10,000 tons of 4M1P products as an example, the specific production method includes:

[0053] Fresh propylene 1 and solvent (dodecane) were heated to 140°C and then entered the loop reactor from material inlet 1. The catalyst mixture (a mixture of catalyst and dodecane with a concentration of 0.1 kg / L) was heated to 140°C and then entered the loop reactor from catalyst inlet 3 for polymerization. Under nitrogen atmosphere, the reactor was operated at 140°C, 5 MPaG, and a space velocity of 1 h -1 The propylene feed rate is 1-3 t / h, the solvent feed rate is 1.5-4.5 t / h, and the catalyst feed rate is 100-300 t / a.

[0054] After the polymerization reaction in the loop reactor, the material passes through the axial flow pump 7, and the reacted material is filtered through the Johnson filter at the reactor outlet and sent to the filter A 9 for coarse filtration. The filtered material enters the security filter 11 for filtration and is sent to the separation unit for separation and purification. The loop reactor is provided with jacket temperature control devices at different positions according to the reaction temperature characteristics, and the jacket temperature control is provided for the part with strict temperature requirements for the reaction, so as to effectively control the reaction temperature of the reactor.

[0055] In the continuous production process, when filter A 9 is blocked, filter A 9 is shut down, filter B 9′ is switched on, the pressure relief valve is opened, the pressure of filter A 9 is relieved, and after the pressure relief is completed, the flushing line is opened to flush filter A 9. The flushed filter A 9 is kept for use. When filter B 9′ is blocked, filter B 9′ is shut down, filter A 9′ is switched on, filter B 9′ is shut down, and the above pressure relief and flushing operation steps are repeated.

[0056] In the continuous production process, the preparation method of Example 1 can achieve a propylene single-pass conversion rate of 60-85%, a polymerization product selectivity of 80-95%, a 4-methyl-1-pentene selectivity of 80-90%, and a 4-methyl-1-pentene product with a purity of 85-98%.

[0057] Example 2

[0058] Combine the following Figure 1 The invention discloses a ring tube reaction device for preparing 4-methyl-1-pentene and a method for preparing 4-methyl-1-pentene.

[0059] like Figure 1 As shown, the loop tube reaction device for preparing 4-methyl-1-pentene includes: a loop tube reactor and a filtering unit connected by pipelines, and the material inlet 1 of the loop tube reactor is set to a circular arc structure, and the circular arc structure is bent toward the inner side. The loop tubes in the loop tube reactor are preferably arranged in a square shape, and the outer periphery of the loop tubes is wrapped with a jacket temperature control device 4. The catalyst inlet 3 of the loop tube reactor is set to a circular arc structure, and the circular arc structure is bent toward the inner side. The loop tube reactor is provided with an axial flow pump 4, and the material outlet of the loop tube reactor is provided with a filter 5. The filtering unit includes two parallel filters A 9 and filter B 9', and a security filter C11 connected in series. The present invention adopts a parallel design of filter A and filter B, which can realize online disassembly. Filter A 9 and filter B 9' adopt Figure 3 The closed filter shown in the figure. Wherein, the radius of the circular arc of the material inlet of the annular tube reactor is 1 / 2 of the diameter of the inlet pipeline, and the radius of the circular arc of the catalyst inlet is 1 / 2 of the diameter of the inlet pipeline.

[0060] Preparation method of 4-methyl-1-pentene:

[0061] Using the above Figure 1 production equipment and Figure 3 The closed filter is used to continuously prepare 4-methyl-1-pentene (4M1P). Taking the annual production of 10,000 tons of 4M1P products as an example, the continuous production method includes:

[0062] Fresh propylene 1 and solvent (dodecane) are heated to 150°C and then enter the loop reactor from material inlet 1. The catalyst mixture (a mixture of catalyst and dodecane with a concentration of 0.2 kg / L) is heated to 150°C and then enters the loop reactor from catalyst inlet 3 for polymerization. Under nitrogen atmosphere, the reactor is operated at a temperature of 150°C, an operating pressure of 5.5 MPaG, and a space velocity of 1 h -1 . After the polymerization reaction in the loop reactor, the material passes through the axial flow pump 7, and the reacted material is filtered through the Johnson filter at the reactor outlet and sent to the filter A 9 for coarse filtration. The filtered material enters the security filter 11 for filtration and is sent to the separation unit for separation and purification; the loop reactor is equipped with jacket temperature control devices at different positions according to the reaction temperature characteristics, and the jacket temperature control is set for the part with strict temperature requirements, so as to effectively control the reaction temperature of the reactor. In the continuous production process, the propylene feed rate is 1-3 t / h, the solvent feed rate is 1.5-4.5 t / h, and the catalyst feed rate is 100-300 t / a.

[0063] In the continuous production process, when filter A 9 is blocked, filter A 9 is shut down, filter B 9′ is switched on, the pressure relief valve is opened, the pressure of filter A 9 is relieved, and after the pressure relief is completed, the flushing line is opened to flush filter A 9. The flushed filter A 9 is kept for use. When filter B 9′ is blocked, filter B 9′ is shut down, filter A 9′ is switched on, filter B 9′ is shut down, and the above pressure relief and flushing operation steps are repeated.

[0064] In the continuous production process, the continuous preparation method of Example 2 can achieve a propylene single-pass conversion rate of 65-85%, a polymerization product selectivity of 85-95%, and a 4-methyl-1-pentene selectivity of 85-90%, and obtain a 4-methyl-1-pentene product with a purity of 95-98%.

[0065] Example 3

[0066] Combine the following Figure 1 The invention discloses a ring tube reaction device for preparing 4-methyl-1-pentene and a method for preparing 4-methyl-1-pentene.

[0067] like Figure 1As shown, the loop tube reaction device for preparing 4-methyl-1-pentene includes: a loop tube reactor and a filtering unit connected by a pipeline, the material inlet 1 of the loop tube reactor is set as an arc structure, and the arc structure is bent toward the inner side. The loop tube in the loop tube reactor is preferably arranged in a square, and the outer periphery of the loop tube is wrapped with a jacket temperature control device 4. The catalyst inlet 3 of the loop tube reactor is set as an arc structure, and the arc structure is bent toward the inner side. The loop tube reactor is provided with an axial flow pump 4, and the material outlet of the loop tube reactor is provided with a filter 5. The filtering unit includes two parallel filters A 9 and filter B 9', and a security filter C11 connected in series, and the filter A and filter B are open filters. The present invention adopts a parallel design of filter A and filter B, which can realize online disassembly. Among them, the radius of the arc of the material inlet of the loop tube reactor is 2 / 3 of the diameter of the inlet pipeline, and the radius of the arc of the catalyst inlet is 2 / 3 of the diameter of the inlet pipeline.

[0068] Preparation method of 4-methyl-1-pentene:

[0069] Using the above Figure 1 production equipment and Figure 2 The open filter is used to continuously prepare 4-methyl-1-pentene. Taking the annual production of 10,000 tons of 4M1P products as an example, the specific production method includes:

[0070] Fresh propylene 1 and solvent (dodecane) are heated to 160°C and then enter the loop reactor from material inlet 1. The catalyst mixture (a mixture of catalyst and dodecane with a concentration of 0.3 kg / L) is heated to 160°C and then enters the loop reactor from catalyst inlet 3 for polymerization. Under nitrogen atmosphere, the reactor operating temperature is 160°C, the operating pressure is 6.5-7.5 MPaG, and the space velocity is 1h -1 . After the polymerization reaction in the loop reactor, the material passes through the axial flow pump 7, and the reacted material is filtered through the Johnson filter at the reactor outlet and sent to the filter A 9 for coarse filtration. The filtered material enters the security filter 11 for filtration and is sent to the separation unit for separation and purification; the loop reactor is provided with jackets 4 at different positions according to the reaction temperature characteristics, and the jacket temperature control is provided for the part with strict temperature requirements for the reaction, so as to effectively control the reaction temperature of the reactor. In the continuous production process, the propylene feed rate is 1-3 t / h, the solvent feed rate is 1.5-4.5 t / h, and the catalyst feed rate is 100-300 t / a.

[0071] In the continuous production process, when filter A 9 is blocked, filter A 9 is shut down, filter B 9′ is switched on, the pressure relief valve is opened, the pressure of filter A 9 is relieved, and after the pressure relief is completed, the flushing line is opened to flush filter A 9. The flushed filter A 9 is kept for use. When filter B 9′ is blocked, filter B 9′ is shut down, filter A 9′ is switched on, filter B 9′ is shut down, and the above pressure relief and flushing operation steps are repeated.

[0072] In the continuous production process, the preparation method of Example 3 can achieve a propylene single-pass conversion rate of 70-85%, a polymerization product selectivity of 65-85%, and a 4-methyl-1-pentene selectivity of 75-85%, and obtain a 4-methyl-1-pentene product with a purity of 85-98%.

[0073] Comparative Example 1

[0074] 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:

[0075] 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.

[0076] 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.

[0077] Comparative Example 2

[0078] The preparation method of Example 2 is used, except that the loop tube reactor adopts a common loop tube reactor, and the material inlet and the catalyst inlet are both designed with commonly used inlet pipelines.

[0079] In the continuous production process, the preparation method of Comparative Example 2 can achieve a propylene single-pass conversion rate of 50-70%, a polymerization product selectivity of 80-90%, and a 4-methyl-1-pentene selectivity of 75-85%, and obtain a 4-methyl-1-pentene product with a purity of 90-97%.

Claims

1. A loop tube reaction device for preparing 4-methyl-1-pentene, include: A loop tube reactor and a filtering unit are connected in sequence, wherein the loop tube reactor is provided with a material inlet and a material outlet; wherein the loop tube at the material inlet of the loop tube reactor is provided with a concave structure, and the tube wall of the concave structure is bent toward the inner side of the loop tube; wherein the material outlet of the loop tube reactor is connected with the filtering unit through a pipeline.

2. The loop tube reaction device according to claim 1, It is characterized in that The loop tube in the loop tube reactor is surrounded by a jacket temperature control device; and / or, The concave surface of the concave structure of the material inlet of the annular tube reactor is an arc surface; preferably, the radius of the arc surface is 1 to 5 times, preferably 2 to 3 times, the diameter of the inlet pipeline; and / or, The loop reactor is also provided with a catalyst inlet.

3. The loop tube reaction device according to claim 2, It is characterized in that The annular tube reactor is provided with a catalyst inlet, and the annular tube at the catalyst inlet is provided with a concave structure, and the tube wall of the concave structure is bent toward the inner side of the annular tube; preferably, the concave surface of the concave structure of the catalyst inlet of the annular tube reactor is an arc surface; more preferably, the radius of the arc surface is 1 to 5 times the diameter of the inlet pipeline, preferably 2 to 3 times.

4. The loop tube reaction device according to claim 1, It is characterized in that The filter unit includes at least two parallel filters and a safety filter C connected in series. Preferably, the filter 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.

5. The loop tube reaction device according to claim 1, It is characterized in that The loop reactor is provided with an axial flow pump; and / or, A filter D is provided at the material outlet of the loop reactor, preferably a Johnson net filter, and more preferably, the filtering accuracy of the Johnson net filter is 5 to 50 μm.

6. A method for preparing 4-methyl-1-pentene, comprising preparing 4-methyl-1-pentene by using the loop tube reaction device according to any one of claims 1 to 5.

7. The preparation method according to claim 6, It is characterized in that The preparation method comprises: feeding propylene, solvent and catalyst into a loop reactor, heating to carry out polymerization reaction, and filtering the materials after the polymerization reaction through a filtering unit and then entering a separation unit for separation and purification.

8. The preparation method according to claim 7, It is characterized in that The operating conditions of the loop reactor are: the reaction is carried out under a protective gas atmosphere, the temperature is 150-200° C., the liquid flow rate is 1-8 m / s, and the average liquid residence time is 2-10 h; and / or, In the filtration unit, the operating conditions of filter A and filter B are: temperature of 150-200° C., pressure of 5.5-9 MPaG, and filtration accuracy of 5-30 μm.

9. The preparation method according to claim 6, 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.

10. Use of a loop tube reaction device for preparing 4-methyl-1-pentene as claimed in any one of claims 1 to 5 or a method for preparing 4-methyl-1-pentene as claimed in any one of claims 6 to 9 in the production of 4-methyl-1-pentene.

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