A 4-methyl-1-pentene separation device and process

Abstract

The present invention discloses a 4-methyl-1-pentene separation device, characterized in that: it includes a baffle distillation tower (3), a vertically arranged baffle (31) is provided inside; an atmospheric distillation tower (6), the feed end of the atmospheric distillation tower (6) is connected to the third discharge end of the baffle distillation tower (3); a vacuum distillation tower (8), the feed end of the vacuum distillation tower (8) is connected to the second discharge end of the atmospheric distillation tower (6); and a gas compressor (9), the low-pressure gas phase inlet of the gas compressor (9) is connected to the first discharge end of the vacuum distillation tower (8), and the high-pressure gas phase outlet of the gas compressor (9) is connected to the return end of the atmospheric distillation tower (6). The present invention also discloses a separation process applied with the 4-methyl-1-pentene separation device. Compared with the prior art, the present invention can reduce the distillation energy consumption and reduce the difficulty of equipment manufacturing.

Description

Technical Field

[0001] The invention relates to the technical field of chemical separation, and in particular to a 4-methyl-1-pentene separation device and process. Background Art

[0002] Propylene dimerization is an important way to produce fine chemicals. Its products mainly include 4-methyl-1-pentene, 1-hexene, 2,3-dimethylbutene, etc. Among these products, 4-methyl-1-pentene is an important polymer monomer. It can be copolymerized with ethylene to prepare linear low-density polyethylene (LLDPE) with excellent performance, and can also be prepared by homopolymerization to prepare poly-4-methyl-1-pentene (PMP). PMP is a new high-end polyolefin resin with excellent light transmittance and heat resistance. For details, please refer to the Chinese invention patent "A PMP copolymer and its preparation method" with patent application number CN202111174055.0 (publication number CN113861348A). However, there is currently no ability to industrially produce the polymerization monomer 4-methyl-1-pentene in China. Therefore, it is of great significance to develop efficient catalysts for the preparation of 4-methyl-1-pentene by propylene dimerization, optimize reaction process conditions, and design product separation processes to achieve industrial production of PMP.

[0003] At present, the common method for preparing 4-methyl-1-pentene in industry is to dimerize propylene under alkali metal catalysis and then purify it by distillation. This method has many side reactions and will produce a large number of isomers, which puts extremely high demands on the separation process. The boiling points of 4-methyl-1-pentene and the main by-product 4-methyl-2-pentene are very close, 53.8℃ and 56.3℃ respectively. Separating and purifying 4-methyl-1-pentene requires a lot of energy, so the separation of the two is the most important link in the production process. Calculation of the 4-methyl-1-pentene distillation tower that separates 45,000 tons / year of 4-methyl-1-pentene shows that if the purity of 4-methyl-1-pentene in the top distillate is 98.5%, the traditional process needs to consume 1.11×10 7 kJ / t of energy, and the number of distillation plates is too large, resulting in high difficulty in equipment manufacturing and high maintenance costs. Summary of the invention

[0004] The first technical problem to be solved by the present invention is to provide a 4-methyl-1-pentene separation device which can reduce the energy consumption of distillation and the difficulty of equipment manufacturing in view of the current status of the prior art.

[0005] The second technical problem to be solved by the present invention is to provide a separation process using the above-mentioned 4-methyl-1-pentene separation device.

[0006] The technical solution adopted by the present invention to solve the above-mentioned first technical problem is: a 4-methyl-1-pentene separation device, characterized in that: it includes:

[0007] A partition distillation tower, wherein a vertically arranged partition is provided inside, wherein a feed end for feeding a product after a propylene dimerization reaction is provided at a first side of the partition in the middle of the partition distillation tower, a first discharge end for discharging a light component is provided at the top of the partition distillation tower, a second discharge end for discharging a heavy component is provided at the bottom of the partition distillation tower, and a third discharge end for discharging an intermediate component is provided at a second side of the partition in the middle of the partition distillation tower;

[0008] An atmospheric distillation tower, having a feed end in the middle, a first discharge end at the top, a second discharge end and a return end at the bottom, wherein the feed end of the atmospheric distillation tower is connected to the third discharge end of the partition distillation tower;

[0009] A vacuum distillation tower, having a feed end and a first discharge end at the top and a second discharge end at the bottom, wherein the feed end of the vacuum distillation tower is connected to the second discharge end of the atmospheric distillation tower; and

[0010] The gas compressor has a low-pressure gas phase inlet and a high-pressure gas phase outlet. The low-pressure gas phase inlet of the gas compressor is connected to the first discharge end of the vacuum distillation tower, and the high-pressure gas phase outlet of the gas compressor is connected to the return end of the atmospheric distillation tower.

[0011] In order to avoid repeated rise and fall of pressure and temperature during the separation process, which would cause unnecessary waste of energy, a step-down method is used to adjust the pressure and temperature of the material.

[0012] A pressure reducer, used to reduce the pressure of the product after the propylene dimerization reaction and recover the pressure energy in the reaction product;

[0013] A first cooler, used to cool down the product after the propylene dimerization reaction;

[0014] A first regulating valve, used for regulating the pressure of the intermediate component;

[0015] A second cooler, for cooling the intermediate component; and

[0016] The second regulating valve is used to regulate the pressure of the material discharged from the second discharge end of the atmospheric distillation tower.

[0017] In order to reduce the pressure and temperature of the product after the propylene dimerization reaction, the feed end of the pressure reducer is used to feed the product after the propylene dimerization reaction, the feed end of the first cooler is connected to the discharge end of the pressure reducer, and the feed end of the partition distillation tower is connected to the discharge end of the first cooler.

[0018] In order to cool the intermediate components, the feed end of the second cooler is connected to the third discharge end of the partition distillation tower, and the feed end of the atmospheric distillation tower is connected to the discharge end of the second cooler.

[0019] In order to adjust the pressure of the intermediate component, the first regulating valve is arranged on the pipeline between the third discharge end of the partition plate distillation tower and the feed end of the second cooler.

[0020] In order to adjust the pressure of the material discharged from the second discharge end of the atmospheric distillation tower, the second regulating valve is arranged on the pipeline between the second discharge end of the atmospheric distillation tower and the feed end of the vacuum distillation tower.

[0021] In order to convert the energy in the high-pressure fluid into electrical energy while performing a decompression operation on the product and improve the energy utilization rate, the pressure reducer is a hydraulic turbine.

[0022] The technical solution adopted by the present invention to solve the above second technical problem is: a separation process using the above 4-methyl-1-pentene separation device, characterized in that it includes the following steps:

[0023] (1) The product after the propylene dimerization reaction with a pressure of 6 to 10 MPa and a temperature of 150 to 160° C. enters the depressurizer, where the pressure is reduced to 1.5 to 3 MPa, and then enters the first cooler after the pressure is reduced to 50 to 60° C.;

[0024] (2) The cooled logistics enters the baffle distillation tower. The top fraction of the baffle distillation tower is a light component mainly composed of propylene. The light component enters the upstream section for recycling. The bottom liquid of the baffle distillation tower is a heavy component mainly composed of C6 and above. The heavy component enters the downstream section. The intermediate component extracted from the side line of the baffle distillation tower is the preliminarily purified 4-methyl-1-pentene.

[0025] (3) The preliminarily purified 4-methyl-1-pentene enters the first regulating valve, where the pressure is reduced to 0.1-0.2 MPa, and then enters the second cooler, where the temperature is reduced to 55-70° C. The cooled stream enters the atmospheric distillation tower, where the top fraction of the atmospheric distillation tower is the 4-methyl-1-pentene product that meets the requirements, and the bottom liquid of the atmospheric distillation tower enters the second regulating valve, where the pressure is reduced to 50-100 kPa;

[0026] (4) The kettle liquid after decompression enters the vacuum distillation tower, and the top fraction of the vacuum distillation tower enters the gas compressor, and after compression, returns to the bottom of the atmospheric distillation tower. The kettle liquid at the bottom of the vacuum distillation tower enters the downstream process section.

[0027] In order to raise the thermal energy of the low-temperature heat source of the top gas of the vacuum distillation tower to a high-temperature level, and at the same time use it as a heat source to introduce it into the bottom of the atmospheric distillation tower to directly heat the bottom kettle liquid, the compression ratio of the gas compressor is 2 to 3.

[0028] In order to replace the light component distillation tower and the heavy component distillation tower in the traditional process, realize the separation of light components and heavy components in the propylene dimerization reaction product, and pre-treat 4-methyl-1-pentene, so that 4-methyl-1-pentene enters the subsequent distillation process with higher purity, and reduce the pressure of the subsequent double-tower distillation, the number of plates of the partition distillation tower is 70-80, one end of the partition is located at the first plate of the distillation tower, and the other end is located between the 5th plate and the 15th plate, the feed plate position is 5-10, and the tower top pressure is 1.5-3MPa;

[0029] The number of plates of the atmospheric distillation tower is 80-100, the feed plate position is 75-85, and the top pressure is 0.1-0.2 MPa;

[0030] The vacuum distillation tower has 50 to 60 plates, the feed plate position is 1 to 3, and the tower top pressure is 50 to 100 kPa.

[0031] Compared with the prior art, the advantages of the present invention are:

[0032] (1) A baffled distillation tower is used to separate propylene and C6 and above components in the product, and 4-methyl-1-pentene is pre-purified at the same time, thereby reducing the difficulty of separation in the subsequent distillation tower;

[0033] (2) A double-tower thermally coupled distillation process is used to reduce the excessive heat load of the reboiler and the excessive number of distillation tower plates in the conventional distillation process, thereby achieving energy conservation and emission reduction and reducing the difficulty of equipment manufacturing;

[0034] (3) A baffle distillation tower and a heat-coupled distillation method are used in combination. The temperature of the top gas of the vacuum tower is increased by compression, and the bottom liquid of the atmospheric tower is directly heated. The top gas of the vacuum tower can directly exchange heat and substances with the bottom liquid of the atmospheric tower. Compared with the indirect heating method using a reboiler, direct heating has a higher heat exchange efficiency and can save about 22% of energy compared with the traditional process. BRIEF DESCRIPTION OF THE DRAWINGS

[0035] Figure 1 Schematic diagram of the structure of a 4-methyl-1-pentene separation device in an embodiment of the present invention;

[0036] Figure 2 This is a schematic diagram of the structure of the 4-methyl-1-pentene separation device in Comparative Example 1 of the present invention;

[0037] Figure 3It is a schematic structural diagram of the 4-methyl-1-pentene separation device in Comparative Example 2 of the present invention;

[0038] Figure 4 This is a schematic diagram of the structure of the 4-methyl-1-pentene separation device in Comparative Example 3 of the present invention. DETAILED DESCRIPTION

[0039] The present invention is further described in detail below with reference to the accompanying drawings.

[0040] like Figure 1 As shown, a preferred embodiment of the 4-methyl-1-pentene separation device of the present invention is shown. The 4-methyl-1-pentene separation device includes a depressurizer 1, a first cooler 2, a baffle distillation tower 3, a first regulating valve 4, a second cooler 5, an atmospheric distillation tower 6, a second regulating valve 7, a vacuum distillation tower 8 and a gas compressor 9.

[0041] The pressure reducer 1 is used to reduce the pressure of the product after the propylene dimerization reaction (the main component of which is a mixture of 4-methyl-1-pentene), and the feed end of the pressure reducer 1 is used to feed the product after the propylene dimerization reaction. In this embodiment, the pressure reducer 1 is a hydraulic turbine, which can convert the energy in the high-pressure fluid into electrical energy while reducing the pressure of the product, thereby improving the energy utilization rate.

[0042] The first cooler 2 is used to cool down the product after the propylene dimerization reaction, and the feed end of the first cooler 2 is connected to the discharge end of the pressure reducer 1.

[0043] The partition distillation tower 3 is used to separate propylene and C6 and above components in the product, and pre-purify 4-methyl-1-pentene at the same time, reducing the difficulty of separation in the subsequent distillation tower. Specifically, a vertically arranged partition 31 is provided inside the partition distillation tower 3, and the middle part of the partition distillation tower 3 is located on the first side of the partition 31 and has a feed end, and the feed end of the partition distillation tower 3 is connected to the discharge end of the first cooler 2, and the top of the partition distillation tower 3 has a first discharge end for light component discharge, and the bottom of the partition distillation tower 3 has a second discharge end for heavy component discharge, and the middle part of the partition distillation tower 3 is located on the second side of the partition 31 and has a third discharge end for intermediate component discharge. In this embodiment, the number of plates of the partition distillation tower 3 is 70 to 80, one end of the partition 31 is located on the first plate of the distillation tower, and the other end is located between the 5th plate and the 15th plate, the feed plate position is 5 to 10, and the tower top pressure is 1.5 to 3 MPa.

[0044] The first regulating valve 4 is used to regulate the pressure of the intermediate component.

[0045] The second cooler 5 is used to cool the intermediate components. The feed end of the second cooler 5 is connected to the third discharge end of the partition distillation tower 3. The first regulating valve 4 is arranged on the pipeline between the third discharge end of the partition distillation tower 3 and the feed end of the second cooler 5.

[0046] The atmospheric distillation tower 6 has a feed end in the middle, a first discharge end at the top, a second discharge end and a return end at the bottom, and the feed end of the atmospheric distillation tower 6 is connected to the discharge end of the second cooler 5. In this embodiment, the number of plates of the atmospheric distillation tower 6 is 80-100, the feed plate position is 75-85, and the tower top pressure is 0.1-0.2 MPa.

[0047] The second regulating valve 7 is used to regulate the pressure of the material discharged from the second discharge end of the atmospheric distillation tower 6 .

[0048] The vacuum distillation tower 8 cooperates with the atmospheric distillation tower 6 to realize double-tower distillation. The double-tower distillation method can reduce the number of distillation tower plates and overcome the difficulties in manufacturing and maintaining the distillation tower. Specifically, the top of the vacuum distillation tower 8 has a feed end and a first discharge end, and the bottom has a second discharge end. The feed end of the vacuum distillation tower 8 is connected to the second discharge end of the atmospheric distillation tower 6, and the second regulating valve 7 is arranged on the pipeline between the second discharge end of the atmospheric distillation tower 6 and the feed end of the vacuum distillation tower 8. In this embodiment, the number of plates of the vacuum distillation tower 8 is 50 to 60, the position of the feed plate is 1 to 3, and the tower top pressure is 50 to 100 kPa.

[0049] The gas compressor 9 has a low-pressure gas phase inlet and a high-pressure gas phase outlet. The low-pressure gas phase inlet of the gas compressor 9 is connected to the first discharge end of the vacuum distillation tower 8, and the high-pressure gas phase outlet of the gas compressor 9 is connected to the return end of the atmospheric distillation tower 6. In this embodiment, the compression ratio of the gas compressor 9 is 2 to 3.

[0050] In this embodiment, the bottom reboiler of the atmospheric distillation tower 6 is eliminated, and the top condenser of the vacuum distillation tower 8 is eliminated. The vapor at the top of the vacuum distillation tower 8 is compressed and sent to the bottom of the atmospheric distillation tower 6. The liquid at the bottom of the atmospheric distillation tower 6 is used as the top reflux of the vacuum distillation tower 8. The pressure of the connecting material between the two towers is adjusted by a gas compressor 9 and a second regulating valve 7. By realizing thermal coupling between the atmospheric distillation tower 6 and the vacuum distillation tower 8, the load of the reboiler at the bottom of the vacuum distillation tower 8 is reduced, and energy is saved.

[0051] Embodiment 1:

[0052] (1) The product after the propylene dimerization reaction at a pressure of 8 MPa and a temperature of 150°C enters the depressurizer 1, where the pressure is reduced to 1.5 MPa, and then enters the first cooler 2 after the pressure is reduced, where the temperature is reduced to 60°C;

[0053] (2) The cooled logistics enters the baffle distillation tower 3. The top fraction of the baffle distillation tower 3 is a light component mainly composed of propylene, which enters the upstream section for recycling. The bottom liquid of the baffle distillation tower 3 is a heavy component mainly composed of C6 and above, which enters the downstream section. The intermediate component extracted from the side line of the baffle distillation tower 3 is the preliminarily purified 4-methyl-1-pentene.

[0054] (3) The preliminarily purified 4-methyl-1-pentene enters the first regulating valve 4, where the pressure is reduced to 0.14 MPa, and then enters the second cooler 5, where the temperature is reduced to 65° C. The cooled stream enters the atmospheric distillation tower 6, where the top fraction of the atmospheric distillation tower 6 is the 4-methyl-1-pentene product that meets the requirements, and the bottom liquid of the atmospheric distillation tower 6 enters the second regulating valve 7, where the pressure is reduced to 68 kPa;

[0055] (4) The kettle liquid after decompression enters the vacuum distillation tower 8, and the top fraction of the vacuum distillation tower 8 enters the gas compressor 9, and returns to the bottom of the atmospheric distillation tower 6 after compression. The kettle liquid at the bottom of the vacuum distillation tower 8 enters the downstream process section.

[0056] Embodiment 2:

[0057] (1) The product after the propylene dimerization reaction at a pressure of 6 MPa and a temperature of 150°C enters the depressurizer 1, where the pressure is reduced to 1.5 MPa, and then enters the first cooler 2 after the pressure is reduced, where the temperature is reduced to 50°C;

[0058] (2) The cooled logistics enters the baffle distillation tower 3. The top fraction of the baffle distillation tower 3 is a light component mainly composed of propylene, which enters the upstream section for recycling. The bottom liquid of the baffle distillation tower 3 is a heavy component mainly composed of C6 and above, which enters the downstream section. The intermediate component extracted from the side line of the baffle distillation tower 3 is the preliminarily purified 4-methyl-1-pentene.

[0059] (3) The preliminarily purified 4-methyl-1-pentene enters the first regulating valve 4, where the pressure is reduced to 0.1 MPa, and then enters the second cooler 5, where the temperature is reduced to 55° C. The cooled stream enters the atmospheric distillation tower 6, where the top fraction of the atmospheric distillation tower 6 is the 4-methyl-1-pentene product that meets the requirements, and the bottom liquid of the atmospheric distillation tower 6 enters the second regulating valve 7, where the pressure is reduced to 55 Kpa;

[0060] (4) The kettle liquid after decompression enters the vacuum distillation tower 8, and the top fraction of the vacuum distillation tower 8 enters the gas compressor 9, and returns to the bottom of the atmospheric distillation tower 6 after compression. The kettle liquid at the bottom of the vacuum distillation tower 8 enters the downstream process section.

[0061] Embodiment 3:

[0062] (1) The product after the propylene dimerization reaction at a pressure of 10 MPa and a temperature of 160° C. enters the depressurizer 1, where the pressure is reduced to 3 MPa, and then enters the first cooler 2 after the pressure is reduced, where the temperature is reduced to 60° C.;

[0063] (2) The cooled logistics enters the baffle distillation tower 3. The top fraction of the baffle distillation tower 3 is a light component mainly composed of propylene, which enters the upstream section for recycling. The bottom liquid of the baffle distillation tower 3 is a heavy component mainly composed of C6 and above, which enters the downstream section. The intermediate component extracted from the side line of the baffle distillation tower 3 is the preliminarily purified 4-methyl-1-pentene.

[0064] (3) The preliminarily purified 4-methyl-1-pentene enters the first regulating valve 4, where the pressure is reduced to 0.2 MPa, and then enters the second cooler 5, where the temperature is reduced to 70° C. The cooled stream enters the atmospheric distillation tower 6, where the top fraction of the atmospheric distillation tower 6 is the 4-methyl-1-pentene product that meets the requirements, and the bottom liquid of the atmospheric distillation tower 6 enters the second regulating valve 7, where the pressure is reduced to 100 Kpa;

[0065] (4) The kettle liquid after decompression enters the vacuum distillation tower 8, and the top fraction of the vacuum distillation tower 8 enters the gas compressor 9, and returns to the bottom of the atmospheric distillation tower 6 after compression. The kettle liquid at the bottom of the vacuum distillation tower 8 enters the downstream process section.

[0066] Comparative Example 1:

[0067] The product of the propylene dimerization reaction at a pressure of 8MPa and a temperature of 150°C is reduced in pressure and cooled, and then enters a propylene distillation tower. The distillate from the top of the tower is a light component mainly composed of propylene, which is returned to the upstream section; the bottom kettle liquid is a component mainly composed of 4-methyl-1-pentene. The kettle liquid passes through a pressure reducing valve and a cooler in turn to reduce the temperature and pressure to 65°C and 0.14MPa, and then enters a 4-methyl-1-pentene distillation tower for separation. The top of the 4-methyl-1-pentene distillation tower is the 4-methyl-1-pentene finally separated, and the bottom kettle liquid is heavy components of C6 and above, which enter the heavy component distillation tower. The heavy component distillation tower separates 4-methyl-2-pentene and components above C6, wherein 4-methyl-2-pentene is distilled from the top of the tower, and components above C6 are distilled from the bottom of the tower and enter the subsequent section. Comparative Example 1 The separation process is as follows Figure 2 shown.

[0068] Comparative Example 2:

[0069] The reaction product with a pressure of 8MPa and a temperature of 150°C enters the next-door tower after decompression and cooling. The bottom kettle liquid of the tower is the heavy components of C6 and above, which enters the subsequent process. The material taken out of the side line of the next-door tower is the pre-purified 4-methyl-1-pentene. After the decompression and cooling operation of the pressure reducing valve and the cooler, the pressure and temperature are 0.14MPa and 65°C respectively, and enters the 4-methyl-1-pentene distillation tower. The 4-methyl-1-pentene finally separated is distilled from the top condenser of the tower. The bottom kettle liquid is the component mainly composed of 4-methyl-2-pentene. Comparative Example 2 Separation process is as follows Figure 3 shown.

[0070] Comparative Example 3:

[0071] The reaction product with a pressure of 8MPa and a temperature of 150°C enters the propylene distillation tower after reduced pressure and cooling. The bottom kettle liquid passes through the pressure reducing valve and the cooler in turn to reduce the pressure and temperature of the bottom material to 0.14MPa and 65°C, and then enters the atmospheric distillation tower; the distillate at the top of the propylene distillation tower returns to the upstream section. The top of the atmospheric tower is the final 4-methyl-1-pentene; the bottom kettle liquid of the atmospheric tower is reduced in pressure to 68kPa by the pressure reducing valve, and then enters the top of the vacuum distillation tower. The bottom kettle liquid of the vacuum tower is the heavy components above C6, which enters the subsequent section; the gas phase at the top of the vacuum tower is pressurized to 0.14MPa by the gas compressor, and then returns to the bottom of the atmospheric tower. Comparative Example 3 Separation process is as follows Figure 4 shown.

[0072] The compositions of the products after propylene dimerization in all the embodiments and comparative examples are shown in Table 1 below.

[0073] Table 1:

[0074] 4-Methyl-1-pentene 4-Methyl-2-pentene Propylene Hexene 2-Methyl-1-pentene mol% 38.1 5.16 52.6 1.98 2.16

[0075] The separation process adopted in the embodiment of the present invention is a distillation process combining the modified 4-methyl-1-pentene bulkhead distillation and thermal coupling distillation. Comparative Example 1 is a traditional original process, Comparative Example 2 is a separation process using only the bulkhead distillation, and Comparative Example 3 is a separation process using only the thermal coupling distillation. The 4-methyl-1-pentene separation process before and after the modification is simulated and calculated using simulation software. The main composition of the 4-methyl-1-pentene finally separated in all the embodiments and comparative examples is shown in Table 2.

[0076] Table 2:

[0077]

[0078] The separation accuracy of all embodiments is consistent with that of all comparative examples, and the annual output of 4-methyl-1-pentene in all embodiments and all comparative examples is 45,000 tons. The energy consumed in the separation process of all embodiments and comparative examples is shown in Table 3

[0079] Table 3:

[0080]

[0081] In Example 1, the gas compressor consumes 8.71×10 5 kJ / t of electrical energy and the vacuum distillation tower consumes 7.34×10 6 kJ / t of heat energy; the reboiler in Comparative Example 1 consumes 1.11×10 7 kJ / t of heat energy; in Comparative Example 2, the reboiler of the 4-methyl-1-pentene distillation tower consumes 1.10×10 7 kJ / t of heat energy; in the double-tower distillation of Comparative Example 3, the gas compressor needs to consume 9.56×10 5 kJ / t of electricity and the vacuum distillation tower consumes 7.92×10 6 kJ / t of thermal energy. Assuming that the thermoelectric conversion coefficient is 3, the energy consumed in the distillation of 4-methyl-1-pentene in Example 1 is compared with that in Comparative Examples 1, 2 and 3, and the energy consumption is saved by 10.4%, 9.54% and 8.71% respectively.

[0082] In addition, the entire separation process requires a total of 1.51×10 7 kJ / t of energy; Comparative Example 1 requires a total of 1.94×10 7 kJ / t of energy; Comparative Example 2 requires a total of 1.76×10 7 kJ / t of energy; Comparative Example 3 requires a total of 1.75×10 7 kJ / t of energy. The separation process adopted in Example 1 can save 22.2%, 14.4% and 13.8% of energy compared with the overall energy consumption of Comparative Examples 1, 2 and 3, respectively.

[0083] From the data in Table 3, it can be concluded that when the final purity of 4-methyl-1-pentene is 98.5%, Comparative Example 1 is a traditional separation process, and both the energy consumption of distilling 4-methyl-1-pentene and the total energy consumption of the separation process are the largest. Comparative Examples 2 and 3 respectively introduced diverter distillation and thermal coupling distillation, and the energy consumption decreased compared with Comparative Example 1, and the total energy consumption decreased by 9.27% ​​and 9.79%, respectively. The introduction of diverter distillation or thermal coupling distillation alone has a better energy-saving effect, and the energy-saving effects of the two are similar.

[0084] Example 1 is a separation process combining distillation in a dividing wall tower and thermal coupling distillation. Compared with Comparative Example 1, the total energy consumption of Example 1 is reduced by 22.2%. Compared with Comparative Example 2 and Comparative Example 3, Example 1 can save 14.4% and 13.8% of energy respectively in the total consumption of the separation process, which is more than twice the energy saving effect of Comparative Example 2 and Comparative Example 3 alone, indicating that distillation in a dividing wall tower and thermal coupling distillation have a good synergistic effect in saving energy. The main reason is that the reaction product is firstly separated in the dividing wall tower to obtain 4-methyl-1-pentene with higher purity, which can reduce the heat load of the subsequent thermal coupling distillation, thereby further enhancing the energy saving effect of the separation process.

Claims

1. A 4-methyl-1-pentene separation device, characterized in that: Included A partition plate distillation tower (3) is provided with a vertically arranged partition plate (31) inside, wherein the partition plate distillation tower (3) has a feed end for feeding a product after a propylene dimerization reaction at a first side of the partition plate (31) in the middle, a first discharge end for discharging a light component at the top of the partition plate distillation tower (3), a second discharge end for discharging a heavy component at the bottom of the partition plate distillation tower (3), and a third discharge end for discharging an intermediate component at a second side of the partition plate (31) in the middle; An atmospheric distillation tower (6) having a feed end in the middle, a first discharge end at the top, a second discharge end and a return end at the bottom, wherein the feed end of the atmospheric distillation tower (6) is connected to the third discharge end of the partition plate distillation tower (3); A vacuum distillation tower (8) having a feed end and a first discharge end at the top and a second discharge end at the bottom, wherein the feed end of the vacuum distillation tower (8) is connected to the second discharge end of the atmospheric distillation tower (6); as well as The gas compressor (9) has a low-pressure gas phase inlet and a high-pressure gas phase outlet. The low-pressure gas phase inlet of the gas compressor (9) is connected to the first discharge end of the vacuum distillation tower (8), and the high-pressure gas phase outlet of the gas compressor (9) is connected to the return end of the atmospheric distillation tower (6).

2. The 4-methyl-1-pentene separation device according to claim 1, characterized in that: Also includes A pressure reducer (1) is used to reduce the pressure of the product after the propylene dimerization reaction and recover the pressure energy in the reaction product; A first cooler (2) is used to cool down the product after the propylene dimerization reaction; A first regulating valve (4) for regulating the pressure of the intermediate component; A second cooler (5) for cooling the intermediate component; and The second regulating valve (7) is used to regulate the pressure of the material discharged from the second discharge end of the atmospheric distillation tower (6).

3. The 4-methyl-1-pentene separation device according to claim 2, characterized in that: The feed end of the pressure reducer (1) is used to feed the product after the propylene dimerization reaction, the feed end of the first cooler (2) is connected to the discharge end of the pressure reducer (1), and the feed end of the partition distillation tower (3) is connected to the discharge end of the first cooler (2).

4. The 4-methyl-1-pentene separation device according to claim 2, characterized in that: The feed end of the second cooler (5) is connected to the third discharge end of the baffle distillation tower (3), and the feed end of the atmospheric distillation tower (6) is connected to the discharge end of the second cooler (5).

5. The 4-methyl-1-pentene separation device according to claim 4, characterized in that: The first regulating valve (4) is arranged on the pipeline between the third discharge end of the partition plate distillation tower (3) and the feed end of the second cooler (5).

6. The 4-methyl-1-pentene separation device according to claim 2, characterized in that: The second regulating valve (7) is arranged on the pipeline between the second discharge end of the atmospheric distillation tower (6) and the feed end of the vacuum distillation tower (8).

7. The 4-methyl-1-pentene separation device according to any one of claims 2 to 6, characterized in that: The pressure reducer (1) is a hydraulic turbine.

8. A separation process using the 4-methyl-1-pentene separation device according to any one of claims 2 to 7, characterized in that The following steps are included: (1) The product after the propylene dimerization reaction at a pressure of 6 to 10 MPa and a temperature of 150 to 160° C. enters the pressure reducer (1), where the pressure is reduced to 1.5 to 3 MPa, and then enters the first cooler (2) after the pressure is reduced, where the temperature is reduced to 50 to 60° C.; (2) The cooled logistics enters the baffle distillation tower (3), the top fraction of the baffle distillation tower (3) is a light component mainly composed of propylene, and the light component enters the upstream section for recycling, the bottom liquid of the baffle distillation tower (3) is a heavy component mainly composed of C6 and above, and the heavy component enters the downstream section, and the intermediate component extracted from the side line of the baffle distillation tower (3) is the preliminarily purified 4-methyl-1-pentene; (3) The preliminarily purified 4-methyl-1-pentene enters the first regulating valve (4), where the pressure is reduced to 0.1-0.2 MPa, and then enters the second cooler (5), where the temperature is reduced to 55-70° C. The cooled stream enters the atmospheric distillation tower (6), where the top fraction of the atmospheric distillation tower (6) is the 4-methyl-1-pentene product that meets the requirements, and the bottom liquid of the atmospheric distillation tower (6) enters the second regulating valve (7), where the pressure is reduced to 50-100 kPa; (4) The kettle liquid after decompression enters the vacuum distillation tower (8), the top fraction of the vacuum distillation tower (8) enters the gas compressor (9), and after compression returns to the bottom of the atmospheric distillation tower (6), and the kettle liquid at the bottom of the vacuum distillation tower (8) enters the downstream process section.

9. The separation process according to claim 8, characterized in that: The compression ratio of the gas compressor (9) is 2-3.

10. The separation process according to claim 8, characterized in that: The number of plates of the partition distillation tower (3) is 70 to 80, one end of the partition (31) is located at the first plate of the distillation tower, and the other end is located between the 5th plate and the 15th plate, the feed plate position is 5 to 10, and the tower top pressure is 1.5 to 3 MPa; The number of plates of the atmospheric distillation tower (6) is 80-100, the feed plate position is 75-85, and the tower top pressure is 0.1-0.2 MPa; The number of plates of the vacuum distillation tower (8) is 50-60, the position of the feed plate is 1-3, and the tower top pressure is 50-100 kPa.

Images