Device for producing high-purity dimer from isobutene

Abstract

The invention relates to a device for producing a dimer from isobutene. The device comprises an isobutene raw material tank, a retarder raw material tank; a reaction unit; a first fractionating tower; a second fractionating tower; a heavy component removal tower; a first condenser and a first return tank are sequentially arranged at the downstream of the first distillate outlet, the first distillate outlet, the first condenser and the first return tank are sequentially communicated, and a first pipe body branch communicated with an outlet of the first return tank is divided into multiple paths and comprises a first return pipe and a second return pipe; the first return pipe is communicated with the upper part of the first fractionating tower; a discharge pipe connected with the first distillate discharge port is divided into a first discharge pipe and a second discharge pipe, and the discharge end of the first discharge pipe is communicated with the lower part of the first fractionating tower. And the first discharge pipe circulates the tower bottom distillate back to the first fractionating tower, and the material is reboiled by the first reboiler in the material circulation process, so that the heat in the first fractionating tower can be balanced.

Description

Technical Field

[0001] The invention relates to the technical field of isobutylene oligomerization, and in particular to a device for producing high-purity dimers from isobutylene. Background Art

[0002] Isobutylene dimer is divided into two isomers (2,4,4-trimethyl-1-pentene and 2,4,4-trimethyl-2-pentene) according to the position of the carbon-carbon double bond. Isobutylene dimer is the key raw material for preparing 3,5,5-trimethylhexanal (isononanal). Isononanal is generally produced by olefin hydroformylation reaction using isobutylene dimer as raw material. High-purity isobutylene dimer can firstly improve the activity and selectivity of the hydroformylation reaction and reduce the occurrence of side reactions, thereby increasing the yield and purity of isononanal. Secondly, high-purity isobutylene dimer can ensure that the catalyst can achieve maximum efficiency and reduce the risk of catalyst deactivation, thereby increasing the conversion rate and selectivity of isononanal and improving the production operation cycle. Furthermore, high-purity isobutylene dimer can react under milder conditions, which helps to reduce the energy consumption and cost of the reaction. Therefore, the production of high-purity isobutylene dimer is crucial to improving the yield and conversion rate of isononanal and the operating life of the catalyst.

[0003] The system for butene oligomerization is disclosed in the invention patent application with patent number CN202180046320.9 (publication number CN115734955A) as "Method for controlled oligomerization of butene". The purity of isobutylene dimer and the conversion rate of isobutylene in the patent are both low for the following reasons:

[0004] 1. The raw material of this patent is a mixed hydrocarbon, and the mixed hydrocarbon feed contains isobutylene and one or more of isobutane, n-butane, 1-butene and 2-butene. This mixed feed will cause isobutylene and n-butene to polymerize to produce 2,5-dimethylhexene, 5,5-dimethylhexene, 2,5-dimethylhexene, 5,5-dimethylhexene. These by-products have a boiling point close to that of isobutylene dimer and are difficult to separate by conventional distillation methods. The by-products will inevitably affect the conversion rate, selectivity and product purity of isononanal.

[0005] 2. This patent does not control the feed ratio of hydrocarbon feedstock to reaction moderator (i.e., retarder) entering the reactor, while a suitable feed ratio is helpful to improve the conversion rate.

[0006] 3. In the entire reaction system, there is no mention of how to balance the heat in containers such as reactors and distillation towers. If external energy is used to balance the heat in the tower, the energy consumption will be high. Summary of the invention

[0007] The technical problem to be solved by the present invention is to provide a device for producing high-purity dimer from isobutylene with low energy consumption in view of the current status of the prior art.

[0008] The technical solution adopted by the present invention to solve the above technical problems is: a device for producing dimers from isobutylene, comprising

[0009] Isobutylene raw material tank, used for containing isobutylene;

[0010] Retarder raw material tank, used to contain retarder;

[0011] The reaction unit has a material inlet for isobutylene and a retarder to enter therein, and a material outlet for the reactants to be discharged;

[0012] a first fractionation tower, provided with a first material inlet, a first distillate outlet and a first distillate discharge port, the first distillate outlet is located at the top of the tower, the first distillate discharge port is located at the bottom of the tower, and the first material inlet is connected to the material outlet of the reaction unit;

[0013] a second fractionation tower, on which a second material inlet, a second distillate outlet and a second distillate discharge port are provided, the second distillate outlet is located at the top of the tower, the second distillate discharge port is located at the bottom of the tower, and the second material inlet is connected to the first distillate discharge port;

[0014] A deweighting tower, which is provided with a third material inlet, a dimer outlet and a heavy component discharge port, wherein the dimer outlet is located at the top of the tower, the heavy component discharge port is located at the bottom of the tower, and the third material inlet is connected to the second distillate discharge port;

[0015] The invention is characterized in that a first condenser and a first reflux tank are sequentially arranged downstream of the first distillate outlet, the first distillate outlet, the first condenser and the first reflux tank are sequentially connected, and the first pipe body connected to the outlet of the first reflux tank is branched into multiple paths, including a first reflux pipe and a second reflux pipe, the first reflux pipe is connected to the upper part of the first distillation tower, and the second reflux pipe is connected to the isobutylene raw material tank;

[0016] The discharge pipe connected to the first distillate discharge port is branched into a first discharge pipe and a second discharge pipe, the discharge end of the first discharge pipe is connected to the lower part of the first fractionation tower, the first discharge pipe is provided with a first reboiler, and the discharge end of the second discharge pipe is connected to the second material inlet of the second fractionation tower. The first discharge pipe circulates the bottom distillate back to the first fractionation tower, and reboils through the first reboiler during the material circulation process, which can balance the heat in the first fractionation tower.

[0017] In order to balance the heat in the second distillation tower, a second condenser and a second reflux tank are provided downstream of the second distillate outlet in sequence, and the second distillate outlet, the second condenser and the second reflux tank are connected in sequence. The second pipe body connected to the outlet of the second reflux tank is branched into two paths, namely a third reflux pipe and a fourth reflux pipe. The third reflux pipe is connected to the upper part of the second distillation tower, and the fourth reflux pipe is connected to the retarder raw material tank.

[0018] The discharge pipe connected to the second distillate discharge port is branched into a third discharge pipe and a fourth discharge pipe. The discharge end of the third discharge pipe is connected to the lower part of the second distillation tower. The third discharge pipe is provided with a second reboiler. The discharge end of the fourth discharge pipe is connected to the third material inlet of the deweighting tower.

[0019] The setting of the third reflux pipe allows the material to flow back to the upper part of the second distillation tower, and the setting of the third discharge pipe allows the material to flow back to the lower part of the second distillation tower, so as to balance the heat in the second distillation tower, so that the distillation effect of the second distillation tower is good, and there is no need to rely on or rely too much on external energy to balance the heat, and the energy consumption is low.

[0020] In order to balance the heat in the deweighting tower, a third condenser and a third reflux tank are provided downstream of the dimer outlet in sequence, and the dimer outlet, the third condenser and the third reflux tank are connected in sequence. The third pipe body connected to the outlet of the third reflux tank is branched into two paths, namely a fifth reflux pipe and a sixth reflux pipe. The fifth reflux pipe is connected to the upper part of the deweighting tower, and the sixth reflux pipe is connected to a container for collecting dimers.

[0021] The discharge pipe connected to the heavy component discharge port is branched into a fifth discharge pipe and a sixth discharge pipe. The discharge end of the fifth discharge pipe is connected to the lower part of the deweighting tower. The fifth discharge pipe is provided with a third reboiler. The discharge end of the sixth discharge pipe is connected to a container for collecting heavy components.

[0022] The fifth reflux pipe is arranged so that the material can flow back to the upper part of the deweighting tower, and the fifth discharge pipe is arranged so that the material can flow back to the lower part of the deweighting tower, so as to balance the heat of the deweighting tower, so that the separation effect of the deweighting tower is good, and there is no need to rely on or rely too much on external energy to balance the heat, and the energy consumption is low.

[0023] Preferably, the isobutylene delivery pipe connected to the outlet of the isobutylene raw material tank and the retarder delivery pipe connected to the outlet of the retarder raw material tank are joined to form a material delivery pipe, which is connected to the material inlet of the reactor. The isobutylene delivery pipe is provided with a first pump body for pumping isobutylene, and the retarder delivery pipe is provided with a second pump body for pumping retarder. The first pump body and the second pump body not only play the role of pumping materials, but also can control the ratio of retarder and isobutylene. By adjusting the ratio of the two, the reaction temperature rise, the reaction single-pass conversion rate, etc. can be adjusted. Preferably, the amount of retarder added is 3% to 6% of the amount of isobutylene added.

[0024] In order to improve the conversion rate of isobutylene and the yield of dimer, the reaction unit includes at least two reactors, each of which has a feed port located at the top and a discharge port located at the bottom, and two adjacent reactors are connected in series or in parallel, the feed port of the reactor located at the most upstream is used as the material inlet, and the discharge port of the reactor located at the most downstream is used as the material outlet.

[0025] In order to improve the purity of the dimer, the purity of the isobutylene is ≥ 99.95%wt, which can reduce the occurrence of side reactions. The reactor is a quench reactor, and the second reflux pipe is branched with multiple branch pipes, which are connected to the reactor one by one, and the materials transported in the branch pipes are used as quench medium. Compared with normal mixed C4 (the content of mixed C4 isobutylene is generally around 20% to 40%wt), the reaction heat release of high-purity isobutylene is 2.5 to 5 times that of mixed C4, so a quench reactor is used to control the temperature of the catalyst bed and reduce the occurrence of side reactions such as trimerization and tetramerization.

[0026] In order to better control the reaction temperature, at least two bed layers are arranged in the reactor from top to bottom, and the branch pipe corresponding to each reactor has multiple drainage ports, and each drainage port is arranged corresponding to a bed layer.

[0027] In order to achieve a high conversion rate of isobutylene and a higher purity and high yield of the obtained dimer, the operating pressure of the reactor is 0.8-1.2 MpaG, the inlet temperature of each bed is 45°C-55°C, and the outlet temperature does not exceed 80°C;

[0028] The amount of retarder added is 3% to 6% of the amount of isobutylene added;

[0029] The first fractionation tower is equipped with 60 to 80 trays, the tower pressure is controlled at 0.6 to 0.8 MPaG, the tower top operating temperature is 53 to 65°C, the tower bottom temperature is 140 to 160°C, and the tower top reflux ratio is 5 to 6;

[0030] 6) The second fractionation tower is provided with 80 to 100 trays, the tower pressure is controlled at 0.1 to 0.2 MPaG, the tower top operating temperature is 85 to 95°C, the tower bottom temperature is 120 to 130°C, and the tower top reflux ratio is 25 to 35;

[0031] 7) The deweighting tower is equipped with 50 to 70 layers of trays, the tower pressure is controlled at 90 kPaA to 100 kPaA, the tower top operating temperature is 100 to 110°C, the tower bottom temperature is 150 to 170°C, and the tower top reflux ratio is 3 to 4.

[0032] Compared with the prior art, the advantages of the present invention are as follows: in the first distillation tower, the first reflux pipe circulates the top distillate back to the upper part of the first distillation tower, the first discharge pipe circulates the bottom distillate back to the lower part of the first distillation tower, and the first discharge pipe reboils the material through the first reboiler during the material circulation process, so that the material is circulated through the first reflux pipe and the first discharge pipe, so that the overall heat balance of the first distillation tower is achieved, the fractionation effect is good, and there is no need to rely on or rely too much on external energy to balance the heat, and the energy consumption is low; in addition, the second reflux pipe refluxes the unreacted isobutylene to the isobutylene raw material tank, which can participate in the reaction again, thereby improving the conversion rate of isobutylene. BRIEF DESCRIPTION OF THE DRAWINGS

[0033] Figure 1 It is a structural schematic diagram of an embodiment of the present invention;

[0034] Figure 2 for Figure 1 A magnified image of point A;

[0035] Figure 3 for Figure 1 Enlarged view of point B. DETAILED DESCRIPTION

[0036] The present invention is further described in detail below with reference to the accompanying drawings.

[0037] like Figures 1 to 3 As shown, the device for producing high-purity dimer from isobutylene in this preferred embodiment includes an isobutylene raw material tank 1, a retarder raw material tank 2, a reactor 3, a first distillation tower 4, a second distillation tower 5 and a deweighting tower 6.

[0038] The isobutylene raw material tank 1 is used for containing isobutylene, and the retarder raw material tank 2 is used for containing the retarder.

[0039] like Figure 1As shown, the isobutylene delivery pipe 11 connected to the outlet of the isobutylene raw material tank 1 and the retarder delivery pipe 21 connected to the outlet of the retarder raw material tank 2 are connected to form a material delivery pipe 10, the isobutylene delivery pipe 11 is provided with a first pump body 12 for pumping isobutylene, and the retarder delivery pipe 21 is provided with a second pump body 22 for pumping retarder. The first pump body 12 and the second pump body 22 not only play the role of pumping materials, but also can control the ratio of the retarder and isobutylene. By adjusting the ratio of the two, the reaction temperature rise, the reaction single-pass conversion rate, etc. can be adjusted. In this embodiment, the amount of retarder added is 3% to 6% of the amount of high-purity isobutylene added, and this ratio is the mass ratio.

[0040] In addition, a preheater 13 is provided on the material conveying pipe 10 to preheat the material so that the material entering the reactor 3 can react at a suitable temperature.

[0041] like Figure 2 As shown, the reaction unit has a material inlet for isobutylene and retarder to enter, a material conveying pipe 10 is connected to the material inlet, and the reaction unit also has a material outlet for the reactants to be discharged.

[0042] The reaction unit includes at least two reactors 3, each of which has a feed port located at the top and a discharge port located at the bottom. Two adjacent reactors 3 are connected in series or in parallel, and the feed port of the reactor 3 located at the most upstream serves as a material inlet, and the discharge port of the reactor 3 located at the most downstream serves as a material outlet.

[0043] In this embodiment, there are two reactors 3 and they are connected in series. Of course, the two reactors 3 can also be connected in parallel, or there are three reactors 3, the first and second reactors 3 are connected in parallel, and the two reactors 3 are connected in series with the third reactor 3. In short, the number of reactors 3 can be at least one, and the connection mode between the reactors 3 can be series, parallel, or a combination of the two.

[0044] The first fractionation tower 4 is provided with a first material inlet 41, a first distillate outlet 42 and a first distillate discharge port 43. The first distillate outlet 42 is located at the top of the tower, the first distillate discharge port 43 is located at the bottom of the tower, and the first material inlet 41 is connected to the material outlet 32 ​​of the reaction unit.

[0045] A first condenser (not shown in the figure) and a first reflux tank 45 are provided in sequence downstream of the first distillate outlet 42. The first distillate outlet 42, the first condenser and the first reflux tank 45 are connected in sequence. The first tube body 46 connected to the outlet of the first reflux tank 45 is branched into multiple paths, including a first reflux pipe 461 and a second reflux pipe 462. The first reflux pipe 461 is connected to the upper part of the first distillation tower 4, and the second reflux pipe 462 is connected to the isobutylene raw material tank 1, so that the unreacted isobutylene is recycled, and the total conversion rate of isobutylene reaches more than 80%wt.

[0046] The discharge pipe connected to the first distillate discharge port 43 is branched into a first discharge pipe 471 and a second discharge pipe 472. The discharge end of the first discharge pipe 471 is connected to the lower part of the first distillation tower 4. The first discharge pipe 471 is provided with a first reboiler 473. The discharge end of the second discharge pipe 472 is connected to the second material inlet 51 of the second distillation tower 5.

[0047] The first reflux pipe 461 circulates the top distillate back to the upper part of the first distillation tower 4, and the first discharge pipe 471 circulates the bottom distillate back to the lower part of the first distillation tower 4. The material is reboiled in the first reboiler 473 during the circulation process in the first discharge pipe 471. The material is circulated through the first reflux pipe 461 and the first discharge pipe 471, so that the overall heat balance of the first distillation tower 4 is achieved, the distillation effect is good, and there is no need to rely on or rely too much on external energy to balance the heat, and the energy consumption is low.

[0048] In addition, the material outlet of the reaction unit (i.e., the outlet 32 ​​of the downstream reactor 3 of this embodiment) is connected to the first material inlet 41 of the first fractionation tower 4 through the feed pipe 33, and the feed pipe 33 and the second discharge pipe 472 are heat exchanged through a heat exchanger (not shown in the figure) so that each material reaches a suitable temperature, and there is no need to use other energy sources to control the material temperature, saving energy consumption. The heat exchanger can adopt an existing structure, such as the feed pipe 33 is connected to the tube side of the heat exchanger, and the second discharge pipe 472 is connected to the shell side of the heat exchanger.

[0049] The second fractionation tower 5 is provided with a second material inlet 51, a second distillate outlet 52 and a second distillate discharge port 53. The second distillate outlet 52 is located at the top of the tower, the second distillate discharge port 53 is located at the bottom of the tower, and the second material inlet 51 is connected to the first distillate discharge port 43. The retarder is selected from at least one of ethanol, butanol and water to reduce the trimerization and tetramerization reactions of isobutylene, and the retarder does not participate in the reaction.

[0050] A second condenser (not shown in the figure) and a second reflux tank 55 are provided in sequence downstream of the second distillate outlet 52. The second distillate outlet 52, the second condenser and the second reflux tank 55 are connected in sequence. The second tube body 56 connected to the outlet of the second reflux tank 55 is branched into two paths, namely a third reflux pipe 561 and a fourth reflux pipe 562. The third reflux pipe 561 is connected to the upper part of the second distillation tower 5, and the fourth reflux pipe 562 is connected to the retarder raw material tank 2, so that the retarder is recycled and reused, thereby effectively reducing the operating cost.

[0051] The discharge pipe connected to the second distillate discharge port 53 is branched into a third discharge pipe 571 and a fourth discharge pipe 572. The discharge end of the third discharge pipe 571 is connected to the lower part of the second distillation tower 5. The third discharge pipe 571 is provided with a second reboiler 573. The discharge end of the fourth discharge pipe 572 is connected to the third material inlet 61 of the deweighting tower 6.

[0052] The setting of the third reflux pipe 561 allows the material to flow back to the upper part of the second distillation tower 5, and the setting of the third discharge pipe 571 allows the material to flow back to the lower part of the second distillation tower 5, so as to balance the heat in the second distillation tower 5, so that the distillation effect of the second distillation tower 5 is good, and there is no need to rely on or rely too much on external energy to balance the heat, and the energy consumption is low.

[0053] The deweighting tower 6 is provided with a third material inlet 61 , a dimer outlet 62 and a heavy component discharge port 63 . The dimer outlet 62 is located at the top of the tower, the heavy component discharge port 63 is located at the bottom of the tower, and the third material inlet 61 is connected to the second distillate discharge port 53 .

[0054] A third condenser (not shown in the figure) and a third reflux tank 65 are provided in sequence downstream of the dimer outlet 62. The dimer outlet 62, the third condenser and the third reflux tank 65 are connected in sequence. The third tube body 66 connected to the outlet of the third reflux tank 65 is branched into two paths, namely a fifth reflux pipe 661 and a sixth reflux pipe 662. The fifth reflux pipe 661 is connected to the upper part of the deweighting tower 6, and the sixth reflux pipe 662 is connected to the container for collecting dimers.

[0055] The discharge pipe connected to the heavy component discharge port 63 is branched into a fifth discharge pipe 671 and a sixth discharge pipe 672. The discharge end of the fifth discharge pipe 671 is connected to the lower part of the deweighting tower 6. The fifth discharge pipe 671 is provided with a third reboiler 673. The discharge end of the sixth discharge pipe 672 is connected to a container for collecting heavy components.

[0056] The setting of the fifth reflux pipe 661 allows the material to flow back to the upper part of the deweighting tower 6, and the setting of the fifth discharge pipe 671 allows the material to flow back to the lower part of the deweighting tower 6, so as to balance the heat of the deweighting tower 6, so that the separation effect of the deweighting tower 6 is good, and there is no need to rely on or rely too much on external energy to balance the heat, and the energy consumption is low.

[0057] The reaction equation for isobutylene dimerization is:

[0058] 1) Main reaction

[0059]

[0060] 2) Side effects

[0061] CH 2 =C(CH 3 ) 2 +(CH 3 ) 3 COH → (CH 3 ) 3 COC(CH 3 ) 3 C8 ether

[0062] 2,4,4-Trimethyl-1-pentene+CH 2 =C(CH 3 ) 2 →Carbadodecene

[0063] 2,4,4-Trimethyl-2-pentene+CH 2 =C(CH3) 2 →Carbadodecene

[0064] As can be seen from the above, if the purity of isobutylene is not high, side reactions will occur, and the resulting polymer is not suitable as a raw material for producing isononanal. The purity of isobutylene in this embodiment is ≥99.95%wt, which can reduce the occurrence of side reactions, and can also effectively reduce the scale of the device and reduce the initial investment of the device.

[0065] Isobutylene polymerization is an exothermic reaction, and the heat released by high-purity isobutylene is 2.5 to 5 times that of normal mixed C4 (the content of isobutylene in mixed C4 is generally around 20% to 40% wt). Therefore, the reactor 3 of this embodiment adopts a quenching reactor to control the temperature of the catalyst bed, reduce the occurrence of side reactions, squeeze out the performance of the catalyst, and extend the operation cycle of the device. A distributor can be set on the top of the reactor 3 to make the temperature distribution of the reactor 3 uniform, and the distributor can adopt an existing structure.

[0066] In order to better control the reaction temperature, at least two beds are arranged in the reactor 3 from top to bottom. In this embodiment, each reactor 3 has three beds. Each bed is provided with multiple multi-point thermocouples to monitor the reaction temperature and interlock to prevent over-temperature of the reaction. The thermocouple can adopt the existing structure.

[0067] The volume ratio of the catalyst in the bed is 0.5:2:3 from top to bottom, and the raw material space velocity of the three beds is controlled at 1-1.2h -1 , 0.25~0.3h -1 and 0.15~0.2h -1 , making the temperature rise of each bed more uniform and improving the reaction effect.

[0068] The second reflux pipe 462 is further branched with a plurality of branch pipes 463, which are connected to the reactors 3 one by one. The material transported in the branch pipes 463 is used as a quenching medium. The branch pipes 463 corresponding to each reactor 3 have a plurality of drain ports 464, and each drain port 464 is set corresponding to a bed layer. In this way, a quenching medium is injected into each bed layer to ensure that the temperature of the material entering the next bed layer is appropriate and to reduce the occurrence of side reactions. In this embodiment, the quenching medium is an inert carbon four that does not participate in the reaction.

[0069] In order to achieve a high conversion rate of isobutylene and a higher purity and high yield of the obtained dimer, the process parameters of each container in this embodiment are set as follows:

[0070] The operating pressure of reactor 3 is 0.8-1.2MpaG, the inlet temperature of each bed is 45°C-55°C, and the outlet temperature does not exceed 80°C;

[0071] The first fractionation tower 4 is provided with 60 to 80 trays, the tower pressure is controlled at 0.6 to 0.8 MPaG, the tower top operating temperature is 53 to 65°C, the tower bottom temperature is 140 to 160°C, and the tower top reflux ratio is 5 to 6;

[0072] The second fractionation tower 5 is provided with 80 to 100 trays, the tower pressure is controlled at 0.1 to 0.2 MPaG, the tower top operating temperature is 85 to 95°C, the tower bottom temperature is 120 to 130°C, and the tower top reflux ratio is 25 to 35;

[0073] The deweighting tower 6 is provided with 50 to 70 layers of trays, the tower pressure is controlled at 90 kPaA to 100 kPaA, the tower top operating temperature is 100 to 110° C., the tower bottom temperature is 150 to 170° C., and the tower top reflux ratio is 3 to 4.

[0074] The process of the device of this embodiment is as follows:

[0075] (1) The isobutylene in the isobutylene raw material tank 1 is sucked by the first pump body 12, and the retarder in the retarder raw material tank 2 is sucked by the second pump body 22, so that the isobutylene and the retarder enter the reactor 3 according to the set ratio, and the amount of the retarder added is 3% to 6% of the amount of the isobutylene added;

[0076] (2) After the reaction in the reactor 3, isobutylene flows to the first distillation tower 4 for fractionation. The gaseous distillate at the top of the tower flows out from the first distillate outlet 42, is condensed by the first condenser, and then flows into the first reflux tank 45. After flowing out from the first tube body 46, it is divided into three paths. One path flows back to the first distillation tower 4 through the first reflux pipe 461, and the liquid material enters the first distillation tower 4 to reduce its internal temperature, which is conducive to achieving the heat balance in the first distillation tower 4. The other path flows back to the isobutylene raw material tank 1 through the second reflux pipe 462, and the isobutylene is recycled to improve the total conversion rate of isobutylene. In addition, during the process of the material refluxing from the second reflux pipe 462 to the isobutylene raw material tank 1, it is also transported from each branch pipe 463 to the corresponding reactor 3 to serve as a quenching medium to balance the heat in the reactor 3.

[0077] After the liquid effluent at the bottom of the tower flows out from the first distillate discharge port 43, one path circulates into the first distillation tower 4 from the first discharge pipe 471 to balance the heat in the first distillation tower 4, and the other path enters the second distillation tower 5 from the second discharge pipe 472. Because a heat exchanger is provided between the second discharge pipe 472 and the feed pipe 33, the material in the second discharge pipe 472 exchanges heat with the material in the feed pipe 33 and finally enters the second distillation tower 5 and the first distillation tower 4 respectively.

[0078] (3) After the material is fractionated in the second distillation tower 5, the gaseous distillate at the top of the tower flows out from the second distillate outlet 52, is condensed by the second condenser, and then flows into the second reflux tank 55. After flowing out from the second tube body 56, it is divided into two paths. One path flows back to the second distillation tower 5 through the third reflux pipe 561, and the liquid material enters the second distillation tower 5 to reduce its internal temperature, which is conducive to achieving heat balance in the second distillation tower 5. The other path flows back to the retarder raw material tank 2 through the fourth reflux pipe 562 for recycling and reuse to reduce costs.

[0079] After the liquid effluent at the bottom of the tower flows out from the second distillate discharge port 53 , one path circulates into the second distillation tower 5 from the third discharge pipe 571 to balance the heat in the second distillation tower 5 , and the other path enters the deweighting tower 6 from the fourth discharge pipe 572 .

[0080] (4) The material is separated in the deweighting tower 6, and the heavy component is discharged from the heavy component discharge port 63 and collected;

[0081] After the light component flows out from the dimer outlet 62, it is condensed by the third condenser and then flows into the third reflux tank 65. After flowing out from the third tube body 66, it branches into two paths, one of which is connected to the deweighting tower 6 through the fifth reflux pipe 661, and the other is connected to the container for collecting dimers through the sixth reflux pipe 662. If the reaction is completed, all the light components will flow out from the sixth reflux pipe 662.

[0082] The device of this embodiment cooperates with the process parameters so that the single-pass conversion rate of the reaction of this embodiment reaches more than 70%, the total conversion rate of the reaction reaches more than 80%, the reaction selectivity reaches more than 90%wt, and the purity of the produced isobutylene dimer product is as high as more than 99.96%, and the water content is ≯200ppm. It can be used as a high-quality raw material for the production of isononanal and has high competitiveness.

[0083] A pump body can be provided on each of the above-mentioned pipe bodies for conveying materials to pump materials to downstream containers or control the on-off of the pipeline; the structures of the above-mentioned isobutylene raw material tank 1, retarder raw material tank 2, reactor 3, first distillation tower 4, second distillation tower 5 and deweighting tower 6, preheater, reboiler and condenser all adopt existing structures.

[0084] In the description of the present invention, it should be understood that the terms "center", "longitudinal", "lateral", "length", "width", "thickness", "up", "down", "front", "back", "left", "right", "vertical", "horizontal", "top", "bottom", "inside", "outside", "clockwise", "counterclockwise", "axial", "radial", "circumferential" and the like indicate orientations or positional relationships based on the orientations or positional relationships shown in the accompanying drawings, and are only for the convenience of describing the present invention and simplifying the description, rather than indicating or implying that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation. Since the embodiments disclosed in the present invention can be arranged in different directions, these terms indicating directions are only for illustration and should not be regarded as limitations. For example, "up" and "down" are not necessarily limited to directions opposite to or consistent with the direction of gravity.

Claims

1. A device for producing high-purity dimer from isobutylene, comprising: An isobutylene raw material tank (1) for containing isobutylene; A retarder raw material tank (2) is used to contain the retarder; The reaction unit has a material inlet for isobutylene and a retarder to enter therein, and a material outlet for the reactants to be discharged; a first fractionation tower (4), on which a first material inlet (41), a first distillate outlet (42) and a first distillate discharge port (43) are provided, wherein the first distillate outlet (42) is located at the top of the tower, the first distillate discharge port (43) is located at the bottom of the tower, and the first material inlet (41) is connected to the material outlet of the reaction unit; a second fractionation tower (5), on which a second material inlet (51), a second distillate outlet (52) and a second distillate discharge port (53) are provided, wherein the second distillate outlet (52) is located at the top of the tower, the second distillate discharge port (53) is located at the bottom of the tower, and the second material inlet (51) is connected to the first distillate discharge port (43); a deweighting tower (6) provided with a third material inlet (61), a dimer outlet (62) and a heavy component discharge port (63), wherein the dimer outlet (62) is located at the top of the tower, the heavy component discharge port (63) is located at the bottom of the tower, and the third material inlet (61) is connected to the second distillate discharge port (53); It is characterized in that A first condenser and a first reflux tank (45) are sequentially provided downstream of the first distillate outlet (42); the first distillate outlet (42), the first condenser and the first reflux tank (45) are sequentially connected; a first pipe body (46) connected to the outlet of the first reflux tank (45) is branched into multiple paths, including a first reflux pipe (461) and a second reflux pipe (462); the first reflux pipe (461) is connected to the upper part of the first fractionation tower (4), and the second reflux pipe (462) is connected to the isobutylene raw material tank (1); The discharge pipe connected to the first distillate discharge port (43) is branched into a first discharge pipe (471) and a second discharge pipe (472). The discharge end of the first discharge pipe (471) is connected to the lower part of the first distillation tower (4). The first discharge pipe (471) is provided with a first reboiler (473). The discharge end of the second discharge pipe (472) is connected to the second material inlet (51) of the second distillation tower (5).

2. The device for producing high-purity dimer from isobutylene according to claim 1, characterized in that: A second condenser and a second reflux tank (55) are provided downstream of the second distillate outlet (52), and the second distillate outlet (52), the second condenser and the second reflux tank (55) are connected in sequence. The second pipe body (56) connected to the outlet of the second reflux tank (55) is branched into two paths, namely a third reflux pipe (561) and a fourth reflux pipe (562). The third reflux pipe (561) is connected to the upper part of the second distillation tower (5), and the fourth reflux pipe (562) is connected to the retarder raw material tank (2). The discharge pipe connected to the second distillate discharge port (53) is branched into a third discharge pipe (571) and a fourth discharge pipe (572). The discharge end of the third discharge pipe (571) is connected to the lower part of the second distillation tower (5). The third discharge pipe (571) is provided with a second reboiler (573). The discharge end of the fourth discharge pipe (572) is connected to the third material inlet (61) of the deweighting tower (6).

3. The device for producing high-purity dimer from isobutylene according to claim 1, characterized in that: A third condenser and a third reflux tank (65) are provided in sequence downstream of the dimer outlet (62); the dimer outlet (62), the third condenser and the third reflux tank (65) are connected in sequence; a third pipe body (66) connected to the outlet of the third reflux tank (65) is branched into two paths, namely a fifth reflux pipe (661) and a sixth reflux pipe (662); the fifth reflux pipe (661) is connected to the upper part of the deweighting tower (6), and the sixth reflux pipe (662) is connected to a container for collecting dimers; The discharge pipe connected to the second distillate discharge port (53) is branched into a third discharge pipe (571) and a fourth discharge pipe (572). The discharge end of the third discharge pipe (571) is connected to the lower part of the second distillation tower (5). The third discharge pipe (571) is provided with a second reboiler (573). The discharge end of the fourth discharge pipe (572) is connected to the third material inlet (61) of the deweighting tower (6).

4. The device for producing high-purity dimer from isobutylene according to claim 1, characterized in that: An isobutylene delivery pipe (11) connected to the outlet of the isobutylene raw material tank (1) and a retarder delivery pipe (21) connected to the outlet of the retarder raw material tank (2) are joined to form a material delivery pipe (10), the material delivery pipe (10) being connected to the material inlet of the reactor unit, the isobutylene delivery pipe (11) being provided with a first pump body (12) for pumping isobutylene, and the retarder delivery pipe (21) being provided with a second pump body (22) for pumping retarder.

5. The device for producing high-purity dimer from isobutylene according to claim 4, characterized in that: The amount of the retarder added is 3% to 6% of the amount of isobutylene added.

6. The device for producing high-purity dimer from isobutylene according to any one of claims 1 to 5, characterized in that: The reaction unit comprises at least two reactors (3), each of the reactors (3) having a feed port (31) located at the top thereof and a discharge port (32) located at the bottom thereof, two adjacent reactors (3) being connected in series or in parallel, the feed port (31) of the reactor (3) located most upstream serves as a material inlet, and the discharge port (32) of the reactor (31) located most downstream serves as a material outlet.

7. The device for producing high-purity dimer from isobutylene according to claim 6, characterized in that: The purity of the isobutylene is ≥99.95%wt, the reactor (3) is a quenching reactor (3), the second reflux pipe (462) is further branched with a plurality of branch pipes (463), the branch pipes (463) are connected to the reactor (3) in a one-to-one correspondence, and the material transported in the branch pipes (463) serves as a quenching medium.

8. The device for producing high-purity dimer from isobutylene according to claim 7, characterized in that: At least two bed layers are arranged in sequence from top to bottom in the reactor (3), and the branch pipe (463) corresponding to each reactor (3) has a plurality of drainage ports (464), and each drainage port (464) is arranged corresponding to a bed layer.

9. The device for producing high-purity dimer from isobutylene according to claim 8, characterized in that: The operating pressure of the reactor (3) is 0.8-1.2 MpaG, the inlet temperature of each bed is 45°C-55°C, and the outlet temperature does not exceed 80°C.

10. The device for producing high-purity dimer from isobutylene according to any one of claims 1 to 5, characterized in that: The first fractionation tower (4) is provided with 60 to 80 layers of trays, the tower pressure is controlled at 0.6 to 0.8 MPaG, the tower top operating temperature is 53 to 65° C., the tower bottom temperature is 140 to 160° C., and the tower top reflux ratio is 5 to 6; The second fractionation tower (5) is provided with 80 to 100 layers of trays, the tower pressure is controlled at 0.1 to 0.2 MPaG, the tower top operating temperature is 85 to 95° C., the tower bottom temperature is 120 to 130° C., and the tower top reflux ratio is 25 to 35; The deweighting tower (6) is provided with 50 to 70 layers of trays, the tower pressure is controlled at 90 kPaA to 100 kPaA, the tower top operating temperature is 100 to 110° C., the tower bottom temperature is 150 to 170° C., and the tower top reflux ratio is 3 to 4.

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