Device for producing high-purity dimer from isobutene

Abstract

The utility model 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 utility model relates to isobutene oligomerization technical field, concretely relates to a device for isobutene production high purity dimer. BACKGROUND

[0002] Isobutene dimer is divided into two isomers (2,4,4-trimethyl-1-pentene and 2,4,4-trimethyl-2-pentene) according to the position of carbon-carbon double bond, and isobutene dimer is a key raw material for preparing 3,5,5-trimethyl hexanal (isoneral). Isoneral is generally prepared by olefin hydroformylation reaction using isobutene dimer as raw material. High purity isobutene dimer can improve the activity and selectivity of hydroformylation reaction, reduce the occurrence of side reactions, thereby improving the yield and purity of isoneral. In addition, high purity isobutene dimer can ensure the maximum efficiency of the catalyst and reduce the risk of catalyst deactivation, thereby improving the conversion rate and selectivity of isoneral and extending the production cycle. Furthermore, high purity isobutene dimer can be reacted under milder conditions, which helps to reduce the energy consumption and cost of the reaction. Therefore, the production of high purity isobutene dimer is crucial for improving the yield, conversion rate and catalyst service life of isoneral.

[0003] The system for butene oligomerization is disclosed in the patent application for method for controlled oligomerization of butenes with patent number CN202180046320.9 (publication number CN115734955A). The purity of isobutene dimer and the conversion rate of isobutene in this patent are relatively low, which is due to the following reasons:

[0004] 1. The raw material used in this patent is mixed hydrocarbon, which contains isobutene and optionally one or more of isobutane, n-butane, 1-butene and 2-butene. This mixed feed will cause isobutene to polymerize with n-butene to form 2,5-dimethylhexene, 5,5-dimethylhexene, 2,5-dimethylhexene and 5,5-dimethylhexene. These by-products have similar boiling points to isobutene dimer and are difficult to separate by conventional fractional distillation methods. The by-products will inevitably affect the conversion rate, selectivity and product purity of isoneral.

[0005] 2. The patent does not control the feed ratio of hydrocarbon raw material and reaction moderator (i.e. polymerization inhibitor) entering the reactor. However, a suitable feed ratio can help improve the conversion rate.

[0006] 3. In the entire reaction system, there is no mention of how to balance the heat in the reactor, fractionating column and other vessels. If external energy is used to balance the heat in the column, the energy consumption will be high. UTILITY MODEL CONTENT

[0007] The utility model relates to a device for high-purity dimer production of isobutene with low energy consumption.

[0008] The utility model discloses a device for dimer production of isobutene which solves the above technical problems, comprising

[0009] Isobutene raw material tank is used for containing isobutene.

[0010] The slow polymerization agent raw material tank is used for containing the slow polymerization agent.

[0011] The reaction unit has a material inlet for isobutene and the slow polymerization agent, and a material outlet for discharging reaction products.

[0012] The first fractionating tower is 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 with the material outlet of the reaction unit.

[0013] The second fractionating tower is provided with a second material inlet, a second distillate outlet and a second distillate discharge port, 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 with the first distillate discharge port.

[0014] The heavy component discharge port is located at the bottom of the tower, and the third material inlet is connected with the second distillate discharge port.

[0015] The first condenser and the 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, the first pipe connected with the outlet of the first reflux tank branches into multiple paths, including a first reflux pipe and a second reflux pipe, the first reflux pipe is connected with the upper part of the first fractionating tower, and the second reflux pipe is connected with the isobutene raw material tank.

[0016] The first distillate discharge port is connected with the first discharge pipe and the second discharge pipe, the discharge end of the first discharge pipe is connected with the lower part of the first fractionating tower, the first discharge pipe is provided with a first reboiler, the discharge end of the second discharge pipe is connected with the second material inlet of the second fractionating tower, and the first discharge pipe circulates the tower bottom distillate back to the first fractionating tower and reboils through the first reboiler in the material circulation process, so that the heat in the first fractionating tower can be balanced.

[0017] In order to balance the heat in the second fractionating tower, a second condenser and a second reflux tank are sequentially arranged downstream of the second distillate outlet, the second distillate outlet, the second condenser and the second reflux tank are sequentially communicated, the second pipe body communicated with the outlet of the second reflux tank is branched into two, which are a third reflux pipe and a fourth reflux pipe, the third reflux pipe is communicated with the upper part of the second fractionating tower, and the fourth reflux pipe is communicated with the polymerization inhibitor raw material tank.

[0018] The discharge pipe connected with 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 communicated with the lower part of the second fractionating tower, the second reboiler is arranged on the third discharge pipe, and the discharge end of the fourth discharge pipe is communicated with the third material inlet of the heavy component removal tower.

[0019] The third reflux pipe is arranged to enable the material to flow back to the upper part of the second fractionating tower, the third discharge pipe is arranged to enable the material to flow back to the lower part of the second fractionating tower, so that the heat in the second fractionating tower is balanced, the fractionating effect of the second fractionating tower is good, and the external energy is not needed or is not excessively needed to balance the heat, and the energy consumption is low.

[0020] In order to balance the heat in the second fractionating tower, a second condenser and a second reflux tank are sequentially arranged downstream of the second distillate outlet, the second distillate outlet, the second condenser and the second reflux tank are sequentially communicated, the second pipe body communicated with the outlet of the second reflux tank is branched into two, which are a third reflux pipe and a fourth reflux pipe, the third reflux pipe is communicated with the upper part of the second fractionating tower, and the fourth reflux pipe is communicated with the polymerization inhibitor raw material tank.

[0021] The discharge pipe connected with 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 communicated with the lower part of the second fractionating tower, the second reboiler is arranged on the third discharge pipe, and the discharge end of the fourth discharge pipe is communicated with the third material inlet of the heavy component removal tower.

[0022] The third reflux pipe is arranged to enable the material to flow back to the upper part of the second fractionating tower, the third discharge pipe is arranged to enable the material to flow back to the lower part of the second fractionating tower, so that the heat in the second fractionating tower is balanced, the fractionating effect of the second fractionating tower is good, and the external energy is not needed or is not excessively needed to balance the heat, and the energy consumption is low.

[0023] Preferably, the isobutylene conveying pipe connected with the outlet of the isobutylene raw material tank and the retarder conveying pipe connected with the outlet of the retarder raw material tank are connected to form a material conveying pipe, which is connected with the material inlet of the reactor, the first pump body for pumping isobutylene is arranged on the isobutylene conveying pipe, and the second pump body for pumping retarder is arranged on the retarder conveying pipe. The first pump body and the second pump body not only function to pump the material, but also control the proportion of the retarder and the isobutylene, and by adjusting the proportion, the reaction temperature rise and the reaction single-pass conversion rate can be adjusted. Preferably, the addition amount of the retarder is 3% to 6% of the addition amount of the isobutylene.

[0024] In order to improve the conversion rate of isobutylene and the yield of the dimer, the reaction unit comprises at least two reactors, each of which has a feeding port at the top and a discharging port at the bottom, and the adjacent two reactors are connected in series or in parallel, the feeding port of the reactor located at the most upstream is the material inlet, and the discharging port of the reactor located at the most downstream is 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 quenching reactor, the second reflux pipe is branched into a plurality of branch pipes, the branch pipes are connected with the reactors one by one, and the material conveyed in the branch pipes is used as a quenching medium. Compared with normal mixed C4 (the isobutylene content in the mixed C4 is generally about 20% to 40%wt), the reaction heat release of high-purity isobutylene is 2.5 to 5 times that of the mixed C4, so a quenching 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, each corresponding branch pipe has a plurality of liquid discharge ports, and each liquid discharge port corresponds to a bed layer.

[0027] In order to make the isobutylene have a high conversion rate, and the prepared dimer have a higher purity and a high yield, the operating pressure of the reactor is 0.8 to 1.2 MPaG, the inlet temperature of each bed layer is 45 to 55℃, and the outlet temperature is not more than 80℃;

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

[0029] The first fractionating column is provided with 60 to 80 trays, the column pressure is controlled at 0.6 to 0.8 MPaG, the operating temperature at the top of the column is 53 to 65℃, the temperature at the bottom of the column is 140 to 160℃, and the reflux ratio at the top of the column is 5 to 6;

[0030] 6) The second fractionating column is provided with 80-100 trays, the column pressure is controlled at 0.1-0.2 MPaG, the operating temperature at the top of the column is 85-95℃, the temperature at the bottom of the column is 120-130℃, and the reflux ratio at the top of the column is 25-35;

[0031] 7) The heavy component removal column is provided with 50-70 trays, the column pressure is controlled at 90-100 kPaA, the operating temperature at the top of the column is 100-110℃, the temperature at the bottom of the column is 150-170℃, and the reflux ratio at the top of the column is 3-4.

[0032] Compared with the prior art, the advantages of the utility model are: in the first fractionating column, the first reflux pipe circulates the overhead distillate to the upper part of the first fractionating column, the first discharge pipe circulates the bottom distillate to the lower part of the first fractionating column, and the first discharge pipe reboils in the first reboiler during the circulation of the material, so that the circulation of the material through the first reflux pipe and the first discharge pipe balances the overall heat of the first fractionating column, the fractionating effect is good, and external energy is not needed or is needed too much to balance the heat, and the energy consumption is low; in addition, the second reflux pipe returns the unreacted isobutene to the isobutene raw material tank, so that the isobutene can participate in the reaction again, and the conversion rate of the isobutene is improved. BRIEF DESCRIPTION OF DRAWINGS

[0033] Figure 1 It is a structure schematic view of the utility model embodiment;

[0034] Figure 2 It is an A enlarged view of Figure 1

[0035] Figure 3 It is a B enlarged view of Figure 1 DETAILED DESCRIPTION

[0036] The utility model will be described further in detail below in combination with the embodiment of the drawings.

[0037] As shown in Figures 1 to 3 The device for producing high-purity dimers from isobutene of the preferred embodiment includes an isobutene raw material tank 1, a retarder raw material tank 2, a reactor 3, a first fractionating column 4, a second fractionating column 5, and a heavy component removal column 6.

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

[0039] As shown in Figure 1 ​​As shown, the isobutene conveying pipe 11 connected to the outlet of the isobutene raw material tank 1 and the retarder conveying pipe 21 connected to the outlet of the retarder raw material tank 2 are connected to form the material conveying pipe 10, the first pump body 12 for pumping isobutene is arranged on the isobutene conveying pipe 11, and the second pump body 22 for pumping retarder is arranged on the retarder conveying pipe 21. The first pump body 12 and the second pump body 22 not only function to pump the material, but also control the proportion of the retarder and the isobutene. By adjusting the proportion of the retarder and the isobutene, the reaction temperature rise and the reaction single-pass conversion rate can be adjusted. In the embodiment, the amount of the retarder added is 3% to 6% of the amount of the high-purity isobutene, and the ratio is a mass ratio.

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

[0041] As shown, Figure 2 The reaction unit has a material inlet for the isobutene and the retarder to enter, the material conveying pipe 10 is connected to the material inlet, and the reaction unit also has a material outlet for discharging the reaction material.

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

[0043] In the embodiment, the reactor 3 has two and is connected in series. Of course, the two reactors 3 can also be connected in parallel, or the reactor 3 has three, 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 summary, the number of reactors 3 can be at least one, and the connection mode between the reactors 3 can be series connection, parallel connection or a combination of the two.

[0044] The first fractionating column 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 column, the first distillate discharge port 43 is located at the bottom of the column, and the first material inlet 41 is connected to the material outlet 32 of the reaction unit.

[0045] The first condenser (not shown in the figure) and the first reflux tank 45 are sequentially arranged downstream of the first distillate outlet 42, and the first distillate outlet 42, the first condenser and the first reflux tank 45 are sequentially connected in communication. The first pipe body 46 connected in communication with the outlet of the first reflux tank 45 branches into multiple paths, including the first reflux pipe 461 and the second reflux pipe 462. The first reflux pipe 461 is connected in communication with the upper part of the first fractionating column 4, and the second reflux pipe 462 is connected in communication with the isobutene raw material tank 1, so as to recycle the unreacted isobutene and achieve an isobutene total conversion rate of 80%wt or more.

[0046] The discharge pipe connected with the first distillate discharge port 43 branches into the first discharge pipe 471 and the second discharge pipe 472. The discharge end of the first discharge pipe 471 is connected in communication with the lower part of the first fractionating column 4, and the first reboiler 473 is arranged on the first discharge pipe 471. The discharge end of the second discharge pipe 472 is connected in communication with the second material inlet 51 of the second fractionating column 5.

[0047] The first reflux pipe 461 circulates the column top distillate back to the upper part of the first fractionating column 4, and the first discharge pipe 471 circulates the column bottom distillate back to the lower part of the first fractionating column 4. The material is reboiled by the first reboiler 473 during the circulation process in the first discharge pipe 471. The circulation of the material by the first reflux pipe 461 and the first discharge pipe 471 balances the overall heat of the first fractionating column 4, has a good fractionation effect, and does not need to or needs to excessively rely on external energy to balance the heat, thereby reducing energy consumption.

[0048] In addition, the material outlet of the reaction unit (i.e. the discharge port 32 of the downstream reactor 3 in the embodiment) is connected in communication with the first material inlet 41 of the first fractionating column 4 through the feed pipe 33. The heat exchanger (not shown in the figure) is arranged between the feed pipe 33 and the second discharge pipe 472 to exchange heat, so that each material reaches a suitable temperature, and other energy sources are not needed to regulate the temperature of the material, thereby saving energy consumption. The heat exchanger can adopt an existing structure, for example, the feed pipe 33 is connected in communication with the tube side of the heat exchanger, and the second discharge pipe 472 is connected in communication with the shell side of the heat exchanger.

[0049] The second fractionating column 5 is provided with the second material inlet 51, the second distillate outlet 52 and the second distillate discharge port 53. The second distillate outlet 52 is located at the top of the column, the second distillate discharge port 53 is located at the bottom of the column, and the second material inlet 51 is connected in communication with the first distillate discharge port 43. The buffer agent is selected from at least one of ethanol, butanol and water, so as to reduce the trimerization and tetramerization reactions of isobutene, and the buffer agent does not participate in the reaction.

[0050] The second distillate outlet 52 is sequentially connected with a second condenser (not shown in the figure) and a second reflux tank 55, and the second distillate outlet 52, the second condenser and the second reflux tank 55 are sequentially communicated. The second pipe body 56 connected with the outlet of the second reflux tank 55 is branched into two paths, i.e., a third reflux pipe 561 and a fourth reflux pipe 562. The third reflux pipe 561 is connected with the upper part of the second fractional distillation tower 5, and the fourth reflux pipe 562 is connected with the buffer agent raw material tank 2, so as to recycle and reuse the buffer agent, thereby effectively reducing the operating cost.

[0051] The discharge pipe connected with 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 with the lower part of the second fractional distillation tower 5, and the second reboiler 573 is arranged on the third discharge pipe 571. The discharge end of the fourth discharge pipe 572 is connected with the third material inlet 61 of the heavy component removal tower 6.

[0052] The third reflux pipe 561 is arranged to enable the material to flow back to the upper part of the second fractional distillation tower 5, and the third discharge pipe 571 is arranged to enable the material to flow back to the lower part of the second fractional distillation tower 5, so as to balance the heat in the second fractional distillation tower 5, thereby enabling the second fractional distillation tower 5 to have good fractional distillation effect and reducing the need for external energy or excessive external energy to balance the heat, and reducing the energy consumption.

[0053] The heavy component removal tower 6 is provided with the 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 with the second distillate discharge port 53.

[0054] The dimer outlet 62 is sequentially connected with a third condenser (not shown in the figure) and a third reflux tank 65, and the dimer outlet 62, the third condenser and the third reflux tank 65 are sequentially communicated. The third pipe body 66 connected with the outlet of the third reflux tank 65 is branched into two paths, i.e., a fifth reflux pipe 661 and a sixth reflux pipe 662. The fifth reflux pipe 661 is connected with the upper part of the heavy component removal tower 6, and the sixth reflux pipe 662 is connected with a container for collecting dimers.

[0055] The discharge pipe connected with 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 with the lower part of the heavy component removal tower 6, and the third reboiler 673 is arranged on the fifth discharge pipe 671. The discharge end of the sixth discharge pipe 672 is connected with a container for collecting heavy components.

[0056] The fifth reflux pipe 661 is arranged to make the material flow back to the upper part of the heavy component removal tower 6, and the fifth discharge pipe 671 is arranged to make the material flow back to the lower part of the heavy component removal tower 6, so as to balance the heat of the heavy component removal tower 6, to make the separation effect of the heavy component removal tower 6 good, and to reduce the use of external energy or the excessive use of external energy to balance the heat, and to reduce the energy consumption.

[0057] The reaction equation of isobutylene dimerization is as follows:

[0058] 1) Main reaction

[0059]

[0060]

[0061] 2) Side reaction

[0062] CH2=C(CH3)2+ (CH3)3COH→ (CH3)3COC(CH3)3 carbon octaether

[0063] 2,4,4-trimethyl-1-pentene + CH2=C(CH3)2→ carbon dodecene

[0064] 2,4,4-trimethyl-2-pentene + CH2=C(CH3)2→ carbon dodecene

[0065] From the above, if the purity of isobutylene is not high, the side reaction will occur, and the generated polymer is not suitable as a raw material for producing isononyl aldehyde. The purity of isobutylene in the embodiment is ≥99.95%wt, which can reduce the occurrence of side reactions, and can also effectively reduce the size of the device and reduce the initial investment of the device.

[0066] The isobutylene polymerization is an exothermic reaction, and the heat release of high-purity isobutylene is 2.5-5 times that of mixed carbon four (the isobutylene content of mixed carbon four is generally about 20%-40%wt). Therefore, the reactor 3 in the embodiment adopts a quenching reactor to control the temperature of the catalyst bed and reduce the occurrence of side reactions, so that the performance of the catalyst is fully utilized, and the operation cycle of the device is prolonged. A distributor can be arranged at the top of the reactor 3 to make the temperature distribution of the reactor 3 uniform, and the distributor can adopt an existing structure.

[0067] In order to better control the reaction temperature, at least two bed layers are arranged in the reactor 3 from top to bottom. In the embodiment, each reactor 3 has three bed layers, and a plurality of multi-point thermocouples are arranged in each bed layer to monitor the reaction temperature and are provided with interlocking to prevent over-temperature reaction. The thermocouples can adopt an existing structure.

[0068] The volume ratio of the catalyst bed layers from top to bottom is 0.5:2:3, and the raw material space velocity of the three bed layers is controlled at 1-1.2 h -10.25~0.3h -1 0.15~0.2h -1 Make each bed temperature more uniform, improve the reaction effect.

[0069] The second reflux pipe 462 is branched into multiple branch pipes 463, which are communicated with the reactors 3 one by one, and the material transported in the branch pipes 463 is used as the quenching medium. Each branch pipe 463 corresponding to each reactor 3 has multiple liquid discharge ports 464, and each liquid discharge port 464 is arranged corresponding to a bed. In this way, the quenching medium is injected corresponding to each bed, ensuring that the temperature of the material entering the next bed is appropriate, reducing the occurrence of side reactions. In the embodiment, the quenching medium is inert carbon four which does not participate in the reaction.

[0070] In order to make isobutylene have high conversion rate, the purity of the prepared dimers is higher and the yield is high, the process parameters of each container of the embodiment are set as follows:

[0071] The operating pressure of the reactor 3 is 0.8~1.2MpaG, the inlet temperature of each bed is 45℃~55℃, and the outlet temperature is not more than 80℃;

[0072] The first fractionating column 4 is provided with 60~80 trays, the column pressure is controlled at 0.6~0.8MPaG, the operating temperature at the top of the column is 53~65℃, the bottom temperature is 140~160℃, and the reflux ratio at the top of the column is 5~6;

[0073] The second fractionating column 5 is provided with 80~100 trays, the column pressure is controlled at 0.1~0.2MPaG, the operating temperature at the top of the column is 85~95℃, the bottom temperature is 120~130℃, and the reflux ratio at the top of the column is 25~35;

[0074] The heavy component removal column 6 is provided with 50~70 trays, the column pressure is controlled at 90kPaA~100kPaA, the operating temperature at the top of the column is 100~110℃, the bottom temperature is 150~170℃, and the reflux ratio at the top of the column is 3~4.

[0075] The process method of the device of the embodiment is:

[0076] (1) The isobutylene in the isobutylene raw material tank 1 is sucked by the first pump body 12, and the slow polymerization agent in the slow polymerization agent raw material tank 2 is sucked by the second pump body 22, so that the isobutylene and the slow polymerization agent enter the reactor 3 according to the set ratio, and the addition amount of the slow polymerization agent is 3%~6% of the addition amount of the isobutylene;

[0077] (2) After the isobutylene reacts in the reactor 3, it flows into the first fractionating column 4 for fractionation. The gaseous distillate from the first distillate outlet 42 flows into the first condenser for condensation, and then flows into the first reflux tank 45. After flowing out of the first pipe 46, the material is divided into three parts. One part flows back into the first fractionating column 4 through the first reflux pipe 461. The liquid material enters the first fractionating column 4 to lower the internal temperature of the first fractionating column 4, which is conducive to achieving the heat balance in the first fractionating column 4. Another part flows back into the isobutylene raw material tank 1 through the second reflux pipe 462, which is recycled for use of the isobutylene, thereby improving the overall conversion rate of the isobutylene. Moreover, the material flows back into the isobutylene raw material tank 1 from the second reflux pipe 462, and is also transported from each branch pipe 463 to the corresponding reactor 3 as a quenching medium to balance the heat in the reactor 3.

[0078] The liquid bottom effluent from the first distillate discharge port 43 flows into the first fractionating column 4 through the first discharge pipe 471 to balance the heat in the first fractionating column 4. Another part of the liquid bottom effluent from the first distillate discharge port 43 flows into the second fractionating column 5 through the second discharge pipe 472. The second discharge pipe 472 and the feed pipe 33 are provided with a heat exchanger. The material in the second discharge pipe 472 exchanges heat with the material in the feed pipe 33, and then finally enters the second fractionating column 5 and the first fractionating column 4, respectively.

[0079] (3) After the material is fractionated in the second fractionating column 5, the gaseous distillate from the second distillate outlet 52 flows into the second condenser for condensation, and then flows into the second reflux tank 55. After flowing out of the second pipe 56, the material is divided into two parts. One part flows back into the second fractionating column 5 through the third reflux pipe 561. The liquid material enters the second fractionating column 5 to lower the internal temperature of the second fractionating column 5, which is conducive to achieving the heat balance in the second fractionating column 5. Another part flows back into the buffer agent raw material tank 2 through the fourth reflux pipe 562, which is recycled for use, thereby reducing the cost.

[0080] The liquid bottom effluent from the second distillate discharge port 53 flows into the second fractionating column 5 through the third discharge pipe 571 to balance the heat in the second fractionating column 5. Another part of the liquid bottom effluent from the second distillate discharge port 53 flows into the heavy-removal column 6 through the fourth discharge pipe 572.

[0081] (4) The material is separated in the heavy-removal column 6. The heavy components are discharged from the heavy component discharge port 63 and collected.

[0082] After the light components flow out of the dimer outlet 62, they are condensed by the third condenser and then flow into the third reflux tank 65. After flowing out of the third pipe 66, the material is divided into two parts. One part flows into the heavy-removal column 6 through the fifth reflux pipe 661. Another part flows into the container for collecting the dimers through the sixth reflux pipe 662. If the reaction is completed, the light components flow out of the sixth reflux pipe 662.

[0083] The device of the embodiment matches the process parameters, so that the single-pass conversion rate of the reaction of the embodiment reaches more than 70%, the total conversion rate of the reaction reaches more than 80%, the reaction selectivity reaches more than 90%wt, the purity of the produced isobutene dimer product is as high as more than 99.96%, the water content is ≯200ppm, and the product can be used as a high-quality raw material for producing isoneral, and has high competitiveness.

[0084] The pump body can be arranged on each pipe body for conveying material to pump the material into the downstream container or control the opening and closing of the pipeline.

[0085] In the description of the utility model, it is understood that the orientation or position relationship indicated by the terms "center", "longitudinal", "transverse", "length", "width", "thickness", "upper", "lower", "front", "rear", "left", "right", "vertical", "horizontal", "top", "bottom", "inner", "outer", "clockwise", "counterclockwise", "axial", "radial", "circumferential" and the like is based on the orientation or position relationship shown in the drawings, and is only for the convenience of describing the utility model and simplifying the description, and does not indicate or imply that the indicated device or element must have a particular orientation, be constructed and operated in a particular orientation, since the disclosed embodiments of the utility model can be arranged in different directions, so these orientation indicating terms are only as an illustration and should not be regarded as a limitation, for example, "upper", "lower" are not necessarily limited to the direction opposite or consistent with the direction of gravity.

Claims

1. An apparatus for producing high-purity dimers from isobutene, comprising an isobutene raw material tank (1) for containing isobutene; a retarder raw material tank (2) for containing a retarder; a reaction unit having a material inlet for isobutene and a retarder to enter, and a material outlet for reaction products to be discharged; a first fractionating column (4) provided with a first material inlet (41), a first distillate outlet (42) at the top and a first distillate discharge port (43) at the bottom, the first material inlet (41) being in communication with the material outlet of the reaction unit; a second fractionating column (5) provided with a second material inlet (51), a second distillate outlet (52) at the top and a second distillate discharge port (53) at the bottom, the second material inlet (51) being in communication with the first distillate discharge port (43); a heavy component removal column (6) provided with a third material inlet (61), a dimer outlet (62) at the top and a heavy component discharge port (63) at the bottom, the third material inlet (61) being in communication with the second distillate discharge port (53); characterized in that a first condenser and a first reflux tank (45) are sequentially arranged downstream of the first distillate outlet (42), the first distillate outlet (42), the first condenser and the first reflux tank (45) are sequentially in communication, a first pipe body (46) in communication with the outlet of the first reflux tank (45) branches into multiple paths, including a first reflux pipe (461) and a second reflux pipe (462), the first reflux pipe (461) is in communication with the upper part of the first fractionating column (4), and the second reflux pipe (462) is in communication with the isobutene raw material tank (1); a discharge pipe connected to the first distillate discharge port (43) branches into a first discharge pipe (471) and a second discharge pipe (472), the discharge end of the first discharge pipe (471) is in communication with the lower part of the first fractionating column (4), the first reboiler (473) is arranged on the first discharge pipe (471), and the discharge end of the second discharge pipe (472) is in communication with the second material inlet (51) of the second fractionating column (5).

2. The apparatus for isobutene production of high purity dimers according to claim 1, characterized by the fact that: a second condenser and a second reflux tank (55) are sequentially arranged downstream of the second distillate outlet (52), the second distillate outlet (52), the second condenser and the second reflux tank (55) are sequentially in communication, a second pipe body (56) in communication with the outlet of the second reflux tank (55) branches into two paths, which are a third reflux pipe (561) and a fourth reflux pipe (562), the third reflux pipe (561) is in communication with the upper part of the second fractionating column (5), and the fourth reflux pipe (562) is in communication with the retarder raw material tank (2). The discharge pipe connected with the second distillate discharge port (53) branches into a third discharge pipe (571) and a fourth discharge pipe (572), the discharge end of the third discharge pipe (571) is connected with the lower part of the second fractionating tower (5), the third discharge pipe (571) is provided with a second reboiler (573), and the discharge end of the fourth discharge pipe (572) is connected with the third material inlet (61) of the heavy component removal tower (6).

3. The apparatus for isobutylene production of high purity dimers according to claim 1, characterized by the fact that: A third condenser and a third reflux tank (65) are sequentially arranged downstream of the dimer outlet (62), the dimer outlet (62), the third condenser and the third reflux tank (65) are sequentially connected in communication, a third pipe body (66) connected with the outlet of the third reflux tank (65) branches into two paths, namely a fifth reflux pipe (661) and a sixth reflux pipe (662), the fifth reflux pipe (661) is connected with the upper part of the heavy component removal tower (6), and the sixth reflux pipe (662) is connected with a container for collecting dimers. The discharge pipe connected with the second distillate discharge port (53) branches into a third discharge pipe (571) and a fourth discharge pipe (572), the discharge end of the third discharge pipe (571) is connected with the lower part of the second fractionating tower (5), the third discharge pipe (571) is provided with a second reboiler (573), and the discharge end of the fourth discharge pipe (572) is connected with the third material inlet (61) of the heavy component removal tower (6).

4. The apparatus for isobutylene production of high purity dimers according to claim 1, characterized by the fact that: The isobutene conveying pipe (11) connected with the outlet of the isobutene raw material tank (1) and the retarder conveying pipe (21) connected with the outlet of the retarder raw material tank (2) are connected to form a material conveying pipe (10), the material conveying pipe (10) is connected with the material inlet of the reaction unit, the isobutene conveying pipe (11) is provided with a first pump body (12) for pumping isobutene, and the retarder conveying pipe (21) is provided with a second pump body (22) for pumping retarder.

5. The apparatus for isobutylene production of high purity dimers according to claim 4, characterized by the fact that: The material conveying pipe (10) is provided with a preheater (13).

6. The apparatus for isobutene production of high purity dimers according to any one of claims 1 to 5, characterized by the fact that: The reaction unit comprises at least two reactors (3), each reactor (3) has a feeding port (31) at the top and a discharging port (32) at the bottom, adjacent two reactors (3) are connected in series or in parallel, the feeding port (31) of the reactor (3) located at the most upstream is used as the material inlet, and the discharging port (32) of the reactor (3) located at the most downstream is used as the material outlet.

7. The apparatus for isobutene production of high purity dimers according to claim 6, characterized by the fact that: The reactor (3) is a quenching reactor (3), and a plurality of branch pipes (463) are further branched from the second reflux pipe (462), the branch pipes (463) are connected in communication with the reactors (3) one by one, and the material conveyed in the branch pipes (463) is used as a quenching medium.

8. The apparatus for isobutene production of high purity dimers according to claim 7, characterized by the fact that: The reactors (3) are sequentially provided with at least two bed layers from top to bottom, the corresponding branch pipes (463) of each reactor (3) have a plurality of liquid discharge ports (464), and each liquid discharge port (464) is provided corresponding to a bed layer.

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