Device and method for producing diisobutylene

Abstract

The present application relates to a diisobutylene production device, which comprises: a contact heat exchanger in which a first heat transfer section is arranged, a first raw material inlet is arranged above the first heat transfer section, and a second raw material inlet is arranged below the first heat transfer section; the reaction separation tower internally comprises a rectifying section and a stripping section, a third raw material inlet is formed in the position, at the rectifying section, of the reaction separation tower, the top end of the contact heat exchanger is communicated to the third raw material inlet, the rectifying section further comprises a first reaction section, and the reaction separation tower is further provided with a fourth raw material inlet; the mixer is communicated with the bottom of the contact heat exchanger; the top end of the contact reactor is communicated with the second raw material inlet, the bottom end of the contact reactor is communicated with the fourth raw material inlet, a second heat transfer section and a second reaction section with a catalyst are arranged in the contact reactor, a fifth raw material inlet is formed above the second heat transfer section, and the mixer is communicated to the fifth raw material inlet. The method can be used for treating the mixed C4 raw material with the isobutene mass fraction being greater than or equal to 50%, and the yield and the purity of the target product diisobutylene are ensured.

Description

Technical Field

[0001] The present application relates to the field of petrochemical industry, and in particular to the selective polymerization of isobutylene to produce diisobutylene. Background Art

[0002] The chemical name of diisobutylene is 2,4,4-trimethyl-pentene, including two isomers, 2,4,4-trimethyl-1-pentene and 2,4,4-trimethyl-2-pentene. It is a volatile, colorless and transparent liquid that can undergo self-polymerization, copolymerization, addition, halogenation, alkylation and carbonylation reactions. It can be used to produce chemical products such as plastic additives, lubricants, antioxidants, surfactants, synthetic detergents, etc. It can also be used directly or after hydrogenation and saturation as a high-octane gasoline blending component. Diisobutylene has a wide range of uses and is usually prepared by selective superposition of isobutylene.

[0003] The heat of reaction of isobutylene dimerization to diisobutylene is -82.8 kJ / mol. When the isobutylene content in the feed is high, the reaction exotherm is large, and the reaction bed temperature rises accordingly. If certain measures are not taken, excessive reaction bed temperature rise will lead to high-temperature deactivation of the catalyst.

[0004] At present, the widely used measure for controlling the temperature rise of the reactor is the fixed bed external circulation cooling method. This method cools part of the reaction products and then recycles them back into the reactor. Since the reaction products contain a large amount of diisobutylene, these reaction products returning to the reactor inlet will cause diisobutylene backmixing, which correspondingly increases the production of side reaction products such as the reaction of diisobutylene with isobutylene to form trimers, and the reaction of trimers with isobutylene to form tetramers, thereby reducing the yield and purity of the target product diisobutylene in the product. Summary of the invention

[0005] The embodiments of the present application provide a production device and method for diisobutylene to solve the technical problem that the yield and purity of the target product diisobutylene are reduced due to the fixed bed external circulation cooling method, and all the reaction heat can be recovered and utilized.

[0006] In a first aspect, an embodiment of the present application provides a production device for diisobutylene, wherein the production device for diisobutylene comprises:

[0007] A contact heat exchanger, wherein the contact heat exchanger has a first heat transfer section, and the contact heat exchanger has a first raw material inlet above the first heat transfer section and a second raw material inlet below the first heat transfer section;

[0008] A reaction separation tower, wherein the reaction separation tower includes a rectifying section and a stripping section arranged from top to bottom, a third raw material inlet is arranged at the rectifying section on the reaction separation tower, the top of the contact heat exchanger is connected to the third raw material inlet, the rectifying section also includes a first reaction section provided with a catalyst, the first reaction section is arranged above the third raw material inlet, the reaction separation tower is further provided with a fourth raw material inlet, and the fourth raw material inlet is arranged at the junction of the rectifying section and the stripping section;

[0009] a mixer, the mixer being in communication with a bottom of the contact heat exchanger;

[0010] A contact reactor, wherein the top of the contact reactor is connected to the second raw material inlet, the bottom of the contact reactor is connected to the fourth raw material inlet through a logistics pipeline, the connection position is at the junction of the distillation section and the stripping section, the upper part of the connection position is the distillation section, and the lower part of the connection position is the stripping section. The contact reactor is provided with a second heat transfer section and a second reaction section provided with a catalyst from top to bottom, the contact reactor is provided with a fifth raw material inlet above the second heat transfer section, and the mixer is connected to the fifth raw material inlet.

[0011] In some embodiments of the present application, the production device of diisobutylene further includes a condenser, a reflux tank and a reflux pump, wherein one end of the condenser is connected to the top of the reaction separation tower, and the other end is connected to the upper part of the reflux tank, the reaction separation tower is provided with a first reflux port at the upper part of the distillation section, one end of the reflux pump is connected to the bottom of the reflux tank, and the other end is connected to the first reflux port, the other end of the reflux pump is also connected to the outside, and a water diversion bucket is also provided at the bottom of the reflux tank;

[0012] The diisobutylene production device also includes a reboiler. The reaction separation tower is also provided with a second reflux port below the stripping section. One end of the reboiler is connected to the second reflux port, and the other end is connected to the bottom end of the reaction separation tower.

[0013] In some embodiments of the present application, the mixer is also connected to the stripping section.

[0014] In some embodiments of the present application, the diisobutylene production device further includes a booster pump, and the mixer is connected to the fifth raw material inlet via the booster pump.

[0015] In some embodiments of the present application, the bottom end of the contact reactor is connected to the fourth raw material inlet through a logistics pipeline, and a control valve is provided on the logistics pipeline. A liquid level regulator is connected to the contact reactor below the second heat transfer section and above the second reaction section, and the liquid level regulator is communicatively connected to the control valve.

[0016] In a second aspect, an embodiment of the present application provides a method for producing diisobutylene, wherein the method for producing diisobutylene is implemented by the diisobutylene production device described in the first aspect, and the method for producing diisobutylene comprises the following steps:

[0017] Introducing a C4 raw material into the contact heat exchanger through the first raw material inlet, and introducing a first gas phase material formed in the contact reactor into the contact heat exchanger through the second raw material inlet;

[0018] Introducing the second liquid phase material formed in the contact heat exchanger into the mixer, and simultaneously introducing a reaction inhibitor from the outside into the mixer;

[0019] introducing the mixed material formed in the mixer into the contact reactor through the fifth raw material inlet;

[0020] The second gas phase material formed in the contact heat exchanger is introduced into the distillation section through the third raw material inlet, and the first liquid phase material formed at the bottom of the contact reactor is introduced into the fourth raw material inlet;

[0021] Unreacted C4 raw material is collected from the top of the reaction separation tower, and diisobutylene is collected from the bottom of the reaction separation tower.

[0022] In some embodiments of the present application, the reaction inhibitor is deoxygenated water.

[0023] In some embodiments of the present application, the ratio of the deoxygenated water to the isobutylene in the C4 raw material is 0 to 0.30:1 in terms of molar ratio.

[0024] In some embodiments of the present application, the method for producing diisobutylene further comprises the following steps:

[0025] The tert-butyl alcohol-diisobutylene azeotrope is extracted from the stripping section and then introduced into the mixer.

[0026] In some embodiments of the present application, the tert-butanol-diisobutylene azeotrope is extracted from the distillation section and then introduced into the mixer, and the ratio of the extracted tert-butanol to the isobutylene in the C4 raw material is 0.05-0.15:1 in terms of molar ratio.

[0027] In some embodiments of the present application, the stripping section has a total of 25 to 35 tower plates, and the tert-butyl alcohol-diisobutylene azeotrope extraction position is located between the 11th to 21st tower plates counting from top to bottom in the stripping section.

[0028] In some embodiments of the present application, the mixed material formed in the mixer is introduced into the contact reactor through the fifth raw material inlet, and the mixed material is introduced into the contact reactor at a temperature of 45 to 58° C. and a pressure of 0.8 to 1.2 MPa; and / or,

[0029] The catalyst provided in the second reaction stage is a macroporous cation exchange resin; and / or,

[0030] The operating conditions of the second reaction stage are: the volume space velocity of the reaction liquid is 0.5 to 5 h -1 , reaction pressure is 0.6-1.0 MPa, and reaction temperature is the bubble point temperature of the material in the second reaction stage under the reaction pressure of the second reaction stage.

[0031] In some embodiments of the present application, the C4 raw material is introduced into the contact heat exchanger through the first raw material inlet, and the C4 raw material is introduced into the contact heat exchanger under a pressure of 0.8-1.2 MPa and a temperature of 35-45° C.; and / or,

[0032] The first gas-phase material formed in the contact reactor is introduced into the contact heat exchanger through the second raw material inlet. The first gas-phase material is introduced into the contact heat exchanger at a pressure of 0.6 to 1.0 MPa and a temperature of 55 to 75°C.

[0033] In some embodiments of the present application, the catalyst provided in the first reaction section is a macroporous cation exchange resin; and / or,

[0034] The operating conditions of the first reaction stage are: the volume space velocity of the reaction liquid is 0.5 to 5 h -1 , reaction pressure is 0.4~1.0MPa, and reaction temperature is 55~75℃.

[0035] In some embodiments of the present application, the distillation section has a total of 15 to 25 tower plates, and the third raw material inlet is located between the 10th to 15th tower plates counting from top to bottom in the distillation section.

[0036] The above technical solution provided by the embodiment of the present application has the following advantages compared with the prior art:

[0037] The production device and method of diisobutylene provided in the embodiment of the present application separate the C4 raw material into two raw materials, namely, liquid phase and gas phase, after multiple mass transfer and heat transfer of the C4 raw material, wherein the light C4 component is enriched in the gas phase, making the reaction temperature easier to control; the heavy C4 component is enriched in the liquid phase, and the isobutylene content is significantly reduced compared with the C4 raw material. Therefore, the present application can process a mixed C4 raw material with an isobutylene mass fraction of ≥50%, while ensuring the yield and purity of the target product diisobutylene. BRIEF DESCRIPTION OF THE DRAWINGS

[0038] The accompanying drawings, which are incorporated in and constitute a part of this specification, illustrate embodiments consistent with the present application and, together with the description, serve to explain the principles of the present application.

[0039] In order to more clearly illustrate the embodiments of the present application or the technical solutions in the prior art, the drawings required for use in the embodiments or the description of the prior art will be briefly introduced below. Obviously, for ordinary technicians in this field, other drawings can be obtained based on these drawings without paying any creative labor.

[0040] Figure 1 A schematic diagram of the structure of a diisobutylene production device provided in an embodiment of the present application. DETAILED DESCRIPTION

[0041] In order to make the purpose, technical solution and advantages of the embodiments of the present application clearer, the technical solution in the embodiments of the present application will be clearly and completely described below in conjunction with the drawings in the embodiments of the present application. Obviously, the described embodiments are part of the embodiments of the present application, not all of the embodiments. Based on the embodiments in the present application, all other embodiments obtained by ordinary technicians in this field without making creative work are within the scope of protection of this application.

[0042] Unless otherwise specified, the terms used herein should be understood as commonly used in the art. Therefore, unless otherwise defined, all technical and scientific terms used herein have the same meaning as those generally understood by those skilled in the art to which this application belongs. In the event of a conflict, this specification takes precedence.

[0043] Unless otherwise specified, various raw materials, reagents, instruments and equipment used in this application can be purchased from the market or prepared by existing methods.

[0044] Those skilled in the art will appreciate that diisobutylene is usually prepared by selective polymerization of isobutylene.

[0045] Isobutylene selective polymerization refers to the polymerization reaction of isobutylene in C4 raw materials containing isobutylene, such as FCC or steam cracking mixed C4, under the action of an acidic catalyst. The chemical reaction formula is as follows:

[0046]

[0047] In the above reaction process, isobutylene is adsorbed on the active center of the catalyst, dissociated, and formed a C4 carbon ion, which then combines with another isobutylene molecule to form a C8 carbon ion. The C8 carbon ion can be desorbed at the active center to form diisobutylene; the C8 carbon ion can also continue to combine with other isobutylene molecules to form C 12 Positive carbon ions make the carbon chain longer.

[0048] Therefore, the side reactions include the further reaction of isobutylene (IB) with the above-mentioned isobutylene dimerization product diisobutylene (DIB) to form a trimer (TIB) and the further reaction of IB with TIB to form a tetramer (TEB):

[0049] IB+DIB→TIB

[0050] IB+TIB→TEB

[0051] Therefore, the side reactions include the further reaction of isobutylene (IB) with the above-mentioned isobutylene dimerization product diisobutylene (DIB) to form a trimer (TIB) and the further reaction of IB with TIB to form a tetramer (TEB):

[0052] In addition, the olefins in the C4 raw material may contain butene-1 and butene-2 ​​in addition to isobutylene. Since isobutylene forms tertiary positive carbon ions that can form secondary positive carbon ions with straight-chain C4 olefins, when mixed C4 is used as a raw material for superposition reaction, there is also a dimerization reaction of isobutylene with butene-1 or butene-2. The former generates side reaction products such as 2,5-dimethylhexene and 5,5-dimethylhexene, and the latter generates side reaction products such as 2,3,3-trimethylpentene, 2,3,4-trimethylpentene, 2,2,4-trimethylpentane, and 3,4,4-trimethylpentene.

[0053] The heat of reaction of isobutylene dimerization to diisobutylene is -82.8 kJ / mol. When the isobutylene content in the feed is high, the reaction exotherm is large, and the reaction bed temperature rises accordingly. If certain measures are not taken, the excessive reaction bed temperature rise will lead to high-temperature deactivation of the catalyst. For example, an isobutylene superposition unit uses FCC mixed carbon four as raw material, and the reactor inlet temperature and inlet pressure are 55°C and 2200 kPa respectively. When isobutylene is superposed, the reaction exotherm and reactor bed temperature rise change with the isobutylene content in the feed, as shown in Table 1.

[0054]

[0055]

[0056] Table 1 Reaction heat and reactor temperature rise as a function of isobutylene content

[0057] It can be seen from Table 1 that as the isobutylene content in the mixed C4 raw material increases, the reaction heat and the reactor temperature rise increase accordingly. When the mass fraction of isobutylene in the feed is 20%, 25%, 30%, and 40%, the reactor temperature rise is 44.11°C, 54.62°C, 64.93°C, and 76.88°C, respectively, and the reactor outlet temperature is 99.11°C, 109.62°C, and 111.71°C, respectively.

[0058] 119.93℃, 131.88℃. Since the acidic cation exchange resin catalyst commonly used in the superposition reaction is seriously deactivated due to the breakage of the polymer chain when the temperature exceeds 120℃, the highest heat-resistant temperature of the acidic cation exchange resin catalyst such as D-005, D-006, QRE-01 and its equivalent superposition catalyst is 120℃. The above 109.62℃ is close to the highest heat-resistant temperature of the catalyst, which is the limit temperature at which the reactor can be operated without taking any cooling measures, while 119.93℃ has reached the highest heat-resistant temperature of the catalyst. Operating at this temperature will cause the catalyst to deactivate quickly. 131.88℃ has exceeded the highest heat-resistant temperature of the catalyst and 15.84% (volume) of the liquid reaction material has been vaporized at this time; in addition, the excessively high temperature of the reaction bed will also lead to an increase in by-products such as trimers and tetramers in the diisobutylene product. Therefore, certain measures must be taken to reduce the temperature rise of the isobutylene superposition reaction.

[0059] At present, the widely used measure for controlling the temperature rise of the reactor is the fixed bed external circulation cooling method. This method cools part of the reaction products and then recycles them back into the reactor. Since the reaction products contain a large amount of diisobutylene, these reaction products returning to the reactor inlet will cause diisobutylene backmixing, which correspondingly increases the production of side reaction products such as the reaction of diisobutylene with isobutylene to form trimers, and the reaction of trimers with isobutylene to form tetramers, thereby reducing the yield and purity of the target product diisobutylene in the product.

[0060] The technical solution provided by the embodiments of the present application is to solve the above technical problems, and the overall idea is as follows:

[0061] In a first aspect, an embodiment of the present application provides a production device for diisobutylene, wherein the production device for diisobutylene comprises:

[0062] A contact heat exchanger 1, wherein the contact heat exchanger 1 is provided with a first heat transfer section 11, wherein the contact heat exchanger 1 is provided with a first raw material inlet 12 above the first heat transfer section 11 and a second raw material inlet 13 below the first heat transfer section 11;

[0063] A reaction separation tower 2, wherein the reaction separation tower 2 includes a rectifying section 21 and a stripping section 22 arranged from top to bottom, a third raw material inlet 23 is arranged at the rectifying section 21 on the reaction separation tower 2, the top of the contact heat exchanger 1 is connected to the third raw material inlet 23, the rectifying section 21 also includes a first reaction section 211 provided with a catalyst, the first reaction section 211 is arranged above the third raw material inlet 23, the reaction separation tower is also provided with a fourth raw material inlet 24, and the fourth raw material inlet 24 is arranged at the junction of the rectifying section and the stripping section;

[0064] A mixer 3, wherein the mixer 3 is connected to the bottom of the contact heat exchanger 1;

[0065] A contact reactor 4, wherein the top end of the contact reactor 4 is connected to the second raw material inlet 13, and the bottom end of the contact reactor 4 is connected to the fourth raw material inlet 24 through a logistics pipeline, and the connection position is at the junction of the distillation section 21 and the stripping section 22. A second heat transfer section 41 and a second reaction section 42 provided with a catalyst are arranged from top to bottom inside the contact reactor 4. A fifth raw material inlet 43 is arranged on the contact reactor 4 above the second heat transfer section 41, and the mixer 3 is connected to the fifth raw material inlet 43.

[0066] The first raw material inlet 12 is used to introduce C4 raw material. The C4 raw material described in the present application has the same meaning as conventional C4 raw materials in the art, such as isobutylene in FCC or steam cracking mixed C4. In addition, the olefins in the C4 raw material may contain butene-1 and butene-2 ​​in addition to isobutylene. The C4 raw material introduced into the contact heat exchanger 1 is in liquid state and moves downward.

[0067] The top of the contact reactor 4 is connected to the second raw material inlet 13. The second raw material inlet 13 is used to introduce the first gas-phase material formed in the contact reactor 4. It is easy to understand that the gas-phase material formed in the contact heat exchanger 1, that is, the second gas-phase material, will be discharged from the top of the contact heat exchanger 1 and then enter the reaction separation tower 2 from the third raw material inlet 23. Under this movement trend, the first gas-phase material will move upward after entering the contact heat exchanger 1.

[0068] The downwardly moving C4 raw material and the upwardly moving C4 raw material will fully exchange heat in the first heat transfer section 11. In the common implementation of the art, the first heat transfer section 11 is filled with fillers, which may be structured fillers or random fillers.

[0069] The C4 raw material and the first gas phase material are in countercurrent contact in the first heat transfer section 11 to carry out mass transfer and heat transfer. The C4 raw material is heated by the first gas phase material flowing from bottom to top to increase its temperature, and the light C4 components such as isobutane, isobutylene and butene-1 therein are more easily vaporized into gas due to receiving heat and enter the first gas phase material; the first gas phase material is cooled by the C4 raw material flowing from top to bottom during the countercurrent contact process, and the heavy C4 components such as n-butane, trans-butene-2 ​​and cis-butene-2 ​​therein are more easily condensed into liquid due to heat release and enter the C4 raw material; this process The process not only allows the C4 raw material to absorb part of the heat, thereby reducing the energy consumption of the reaction separation tower 2; it also reduces the concentrations of isobutylene and butene-1 in the C4 raw material, thereby facilitating the treatment of mixed C4 materials with a high isobutylene content, and is beneficial to reducing the superposition reaction intensity and superposition reaction rate in the second reaction section 42, and is also beneficial to reducing the amount of by-products such as 2,5-dimethylhexene, 5,5-dimethylhexene and trimers generated, and is also beneficial to increasing the yield and purity of 2,4,4-trimethyl-pentene in the diisobutylene product and reducing the loss of butene-1.

[0070] It is worth noting that the isobutylene and butene-1 in the C4 raw material are heated and vaporized in the first heat transfer section 11 and then enter the first gas phase material, so that the concentration of isobutylene and butene-1 in the C4 raw material is reduced. The reduction range is related to the composition of the C4 raw material, the height of the packing layer of the first heat transfer section 11, the contact time between the C4 raw material and the first gas phase material, the distribution state of the feed liquid, etc. For example, the higher the content of isobutylene and butene-1 in the C4 raw material, the higher the height of the packing layer of the first heat transfer section 11, the longer the contact time between the C4 raw material and the first gas phase material, and the greater the spray density of the feed liquid, the better the mass transfer and heat transfer effect, and the greater the reduction range of the isobutylene and butene-1 concentration. The overall result is that the isobutylene concentration in the material entering the second reaction section 42 is significantly lower than the isobutylene concentration in the C4 raw material from the outside of the device, and the superposition reaction intensity and superposition reaction rate of the second reaction section 42 are correspondingly reduced. Therefore, the contact reactor 4 can be used to enable the device to process mixed C4 raw materials with a high isobutylene content.

[0071] As an example, the contact heat exchanger 1 includes a vertical section and a horizontal section that are interconnected, and the vertical section is arranged above the horizontal section. The C4 raw material is subjected to mass transfer and heat transfer in the first heat transfer section 11 to form a second liquid phase material. The second liquid phase material moves downward to leave the vertical section and flows to the lower horizontal section by gravity. The horizontal section buffers the second liquid phase material and separates the gas carried by the second liquid phase material. Then, the second liquid phase material leaves the bottom of the horizontal section and enters the mixer 3. In some preferred schemes, the second liquid phase material is mixed with the tert-butyl alcohol-diisobutylene azeotrope extracted from the distillation section 22 and the deoxygenated water from the outside in the mixer 3 to form a mixed material.

[0072] The mixed material enters the contact reactor 4 from the fifth raw material inlet 43, and contacts the gaseous material flowing from the second reaction section 42 from bottom to top in a countercurrent manner in the second heat transfer section 41, and performs mass transfer and heat transfer. The mixed material is heated by the gaseous material flowing from bottom to top, so that the temperature rises, and the light carbon four components (boiling point temperature see Table 2) such as isobutane, isobutylene, butene-1 are more easily vaporized into gas due to receiving heat and enter the gaseous material from the second reaction section 42; the gaseous material from the second reaction section 42 is cooled by the mixed material flowing from top to bottom during the countercurrent contact process, and the heavy carbon four components such as normal butane, trans-butene-2, cis-butene-2 ​​are more easily condensed into liquid due to heat release and enter the mixed material; the gaseous material from the second reaction section 42 forms the first gaseous material after mass transfer and heat transfer in the second heat transfer section 41. This process not only allows the mixture to absorb part of the reaction heat from the second reaction section 42, but also reduces the concentration of isobutylene and butene-1 in the reaction feed, thereby helping to reduce the intensity and rate of the superposition reaction of the mixture in the subsequent second reaction section 42, and also helps to reduce the amount of by-products such as 2,5-dimethylhexene, 5,5-dimethylhexene and trimers generated, and also helps to increase the yield and purity of 2,4,4-trimethyl-pentene in the diisobutylene product and reduce the loss of butene-1.

[0073]

[0074] Table 2 Boiling point temperatures of C4 components and diisobutylene at different operating pressures

[0075] After the mixture is subjected to mass and heat transfer in the second heat transfer section 41, it continues to flow from top to bottom and enters the second reaction section 42 containing the catalyst. In some examples, the operating conditions of the second reaction section 42 are: the volume space velocity of the reaction liquid is 0.5 to 5 h -1, reaction pressure 0.6~1.0MPa, reaction temperature is the bubble point temperature of the material in the second reaction section under the reaction pressure of the second reaction section. Under the action of the catalyst, the isobutylene in the mixture undergoes a superposition reaction and releases heat, and the temperature of the mixture rises. When the temperature rises to the bubble point temperature under the reaction pressure, the temperature no longer rises. The reaction heat generated by the reaction is only used for the vaporization of the reaction feed, so that the internal temperature of the second reaction section 42 remains unchanged, and there is no problem of catalyst deactivation caused by the reaction heat increasing the reaction temperature. Such a setting avoids the disadvantage of increasing the trimer and tetramer content in the reactants caused by cooling part of the reaction product and recycling it to the inlet of the contact reactor 4, which is beneficial to improving the conversion rate of isobutylene to diisobutylene and also beneficial to reducing costs. The reaction feed will produce gas phase material and first liquid phase material during the superposition process of the second reaction section 42, wherein the gas phase material forms the first gas phase material after mass transfer and heat transfer in the second heat transfer section 41, and the first gas phase material mainly includes vaporized carbon four components, contains more light carbon four components such as isobutane, isobutylene, butene-1, and also includes other light substances such as water-carbon four component azeotrope generated during the reaction; the first liquid phase material mainly includes diisobutylene. As shown in Table 2, the boiling point temperature of diisobutylene is much higher than the boiling point temperature of mixed carbon four, so it is basically not vaporized. The first liquid phase material also includes more heavy carbon four components such as normal butane, trans-butene-2, and cis-butene-2.

[0076] The contact reactor 4 provided in the present application has the following beneficial effects: it reduces the concentration of isobutylene in the reaction feed, which is beneficial to reducing the intensity of the superposition reaction, the superposition reaction rate and the amount of by-products such as trimers; it reduces the concentration of butene-1 in the mixture, which is beneficial to reducing the amount of by-products such as 2,5-dimethylhexene and 5,5-dimethylhexene with lower octane numbers, and improves the yield and purity of 2,4,4-trimethyl-pentene in the diisobutylene product; it does not require an external circulation loop, the reaction temperature is easy to control, the diisobutylene selectivity is high, the superposition reaction is operated under liquid phase conditions, and has the advantage of a high isobutylene conversion rate; it reduces the loss of butene-1 in the C4 raw material; the heat of the superposition reaction is all used for mass transfer and heat transfer between the gas and liquid phases, which greatly reduces the energy consumption of the device.

[0077] The second gas phase material formed in the contact heat exchanger 1 is discharged from the top of the contact heat exchanger 1 and enters the reaction separation tower 2 from the third raw material inlet 23. The first liquid phase material formed at the bottom of the contact reactor 4 is connected to the fourth raw material inlet 24 through a logistics pipeline. The fourth raw material inlet 24 is located at the junction of the rectifying section 21 and the stripping section 22. The rectifying section 21 is located above the fourth raw material inlet 24, and the stripping section 22 is located below the fourth raw material inlet 24.

[0078] In the case where the mixed material contains deoxygenated water, the first liquid phase material and the second gas phase material contain water, tert-butanol, C4 component, diisobutylene and other components. These components will form a variety of water-C4 component azeotropes after entering the reaction separation tower 2. For example, the water-C4 component azeotrope and azeotropic composition at 0.5MPa and 1.0MPa can be obtained by Aspen Plus calculation, as shown in Table 3 and Table 4 respectively.

[0079]

[0080] Table 3 Water-C4 azeotrope and azeotropic composition at 0.5MPa

[0081]

[0082] Table 4 Water-C4 azeotrope and azeotropic composition at 1.0 MPa

[0083] As can be seen from Table 3 and Table 4, with the increase of operating pressure, the types of water-carbon four component azeotropes increase and the content of water in the azeotropes increases. In the reaction separation tower 2, these azeotropes flow from bottom to top. When flowing to the first reaction section 211, isobutylene undergoes a superposition reaction under the action of the catalyst, and water and isobutylene are hydrated to form tert-butyl alcohol. Water and the tert-butyl alcohol generated by hydration can be covered on the active center of the catalyst as a composite inhibitor to inhibit the generation of polymers and to improve the selectivity of diisobutylene in the product. Once diisobutylene is generated, it leaves the first reaction section 211 under the separation effect, which reduces the generation of side reaction products such as trimers and is also beneficial to improving the selectivity of diisobutylene in the product; since the first reaction section 211 is arranged in the distillation section 21, when the composition in the tower is the same, the operating conditions in the first reaction section 211 are moderate, and the reaction temperature is only related to the operating pressure of the reaction separation tower 2, and there is no obvious hot spot, which is beneficial to reduce the generation of side reaction products such as 2,5-dimethylhexene and 5,5-dimethylhexene.

[0084] After the superposition reaction in the first reaction section 211 is completed, the remaining C4 component (i.e., the unreacted C4 component), the water-C4 component azeotrope, and the remaining water leave the first reaction section 211 together, rise to the top of the reaction separation tower 2, and leave the reaction separation tower 2. The diisobutylene product generated in the first reaction section 211 flows downward to the bottom of the reaction separation tower 2, is collected at the bottom of the reaction separation tower 2, and is discharged.

[0085] The beneficial effects of this application include but are not limited to the following:

[0086] First, since isobutylene in the C4 raw material is relatively volatile and 65% to 95% of the superposition reaction is completed in the second reaction section 42, the device and method disclosed in the present application can make the isobutylene concentration in the reaction feed lower than the isobutylene concentration in the C4 raw material, thereby reducing the intensity of the superposition reaction, reducing the reaction temperature rise, allowing the reaction to proceed in a milder state, thereby reducing the generation of side reaction products such as trimers;

[0087] Second, since butene-1 in the C4 raw material is relatively volatile and 65% to 95% of the superposition reaction is completed in the second reaction section 42, the device and method disclosed in the present application can make the concentration of butene-1 in the reaction feed of the second reaction section 42 lower than the concentration of butene-1 in the C4 raw material, thereby reducing the superposition of butene-1 and isobutylene to generate excessive by-products such as 2,5-dimethylhexene and 5,5-dimethylhexene. When the diisobutylene product is used as a chemical raw material, the purity of the product can be improved. When the diisobutylene product is used as a blending component for automotive gasoline, the octane number of the product can be improved, thereby greatly improving the quality of the diisobutylene product;

[0088] Third, the reaction temperature rise of the contact reactor 4 is easy to control, and the fixed bed external circulation method is not adopted, which avoids the problem of diisobutylene back-mixing caused by the reaction product being cooled to remove the reaction heat and then returned to the reactor inlet, which not only increases the driving force of the isobutylene dimerization reaction, but also further reduces the amount of diisobutylene and isobutylene superimposed again to generate trimer, so that the utilization rate of the catalyst and the selectivity of the target product diisobutylene in the product are greatly improved;

[0089] Fourth, it can ensure that the superposition reaction in the contact reactor 4 is always operated under liquid phase conditions, further improving the utilization rate of the catalyst and achieving a high isobutylene conversion rate;

[0090] Fifth, it avoids the superposition reaction of excessive butene-1 with isobutylene, reducing the loss of butene-1 in the C4 raw material;

[0091] Sixth, the heat of the superposition reaction is all used for gas-liquid two-phase mass transfer and heat transfer in the first heat transfer section 11 and the second heat transfer section 41, which greatly saves the energy consumption of the device;

[0092] Seventh, the second gas phase material and the first liquid phase material enter the reaction separation tower from different positions, thereby improving the separation efficiency of the reaction separation tower and saving the energy used for separation;

[0093] Eighth, the tert-butyl alcohol supplementary pipeline and purifier disclosed in other devices and methods are eliminated, and the tert-butyl alcohol generated by the azeotropic water with light hydrocarbons such as isobutylene and the tert-butyl alcohol generated by the hydration of the water and isobutylene is used to replace the tert-butyl alcohol from the outside as an inhibitor of the superposition reaction of the reaction separation tower 2, thereby avoiding the situation in which a large amount of tert-butyl alcohol is injected into the tower from the outside during the start-up process of other devices and methods, and the tert-butyl alcohol with a high freezing point is easy to crystallize and cause the tower plate to be blocked, thereby reducing the tert-butyl alcohol consumption and operating costs, and simplifying the process;

[0094] Ninth, it can process mixed C4 raw materials with high isobutylene content: after the reaction feed containing C4 components, tert-butyl alcohol-diisobutylene azeotrope, and deoxygenated water with large latent heat of vaporization has been subjected to multiple mass transfer and heat transfer in the contact reactor 4 and the contact heat exchanger 1, the isobutylene content in the first reaction section 211 and the second reaction section 41 has been significantly reduced compared with the C4 raw material, so that the device and method disclosed in the present application can process mixed C4 raw materials with an isobutylene mass fraction of ≥50%; in contrast, conventional mixed-phase bed reactors cannot process mixed C4 with high isobutylene content; the standard reaction heat of etherification reaction of isobutylene and methanol to generate 1 mol MTBE can be easily calculated from the standard molar formation enthalpy, etc., which is -39.7 kJ / mol, while the standard reaction heat of dimerization of isobutylene to generate 1 mol diisobutylene is -82.8 kJ / mol. Therefore, in terms of etherification reaction and superposition reaction, the reaction heat generated by each reaction of 1 mol of isobutylene is roughly equivalent, and the reaction heat generated by the superposition reaction is slightly higher. A large number of documents (such as Gao Buliang, ed. High-octane gasoline component production technology [M]. Beijing: China Petrochemical Press, 2006: page 156, second paragraph) point out that if the isobutylene content in the raw material is 34%, the heat released by the reaction is sufficient to vaporize all the unreacted C4 in the mixed-bed etherification reactor. From this, it can be simply inferred that when a conventional mixed-bed reactor is used for isobutylene superposition reaction, the isobutylene content in the raw material C4 should not exceed 34%, otherwise the reaction heat will vaporize all the unreacted C4; it can be seen that the contact reactor 4 disclosed in the present application can process mixed C4 with a higher isobutylene content, and its application range is wider.

[0095] In some embodiments of the present application, the production device of diisobutylene also includes a condenser 51, a reflux tank 52 and a reflux pump 53, wherein one end of the condenser 51 is connected to the top of the reaction separation tower 2, and the other end is connected to the upper part of the reflux tank 52, the reaction separation tower 2 is provided with a first reflux port at the upper part of the distillation section 21, one end of the reflux pump 53 is connected to the bottom of the reflux tank 52, and the other end is connected to the first reflux port, the other end of the reflux pump 53 is also connected to the outside, and a water diversion bucket 521 is also provided at the bottom of the reflux tank 52.

[0096] After the superposition reaction in the first reaction section 211 is completed, the remaining C4 raw material, the water-C4 component azeotrope and the remaining water leave the first reaction section 211 together and rise to the top of the reaction separation tower 2. After condensation by the condenser 51 and pressure-boosting by the reflux pump 53, they are divided into two parts: one part is used as reflux, and the other part is used as the remaining C4 raw material delivery device; since most of the water-C4 component azeotrope are non-homogeneous azeotropes, this part of water will be stratified with the light component in the reflux tank 52. Therefore, the remaining water and the water in the water-C4 component azeotrope can be separated from the water separator 521 and directly discharged as sewage or recycled.

[0097] In some embodiments of the present application, the diisobutylene production device further includes a reboiler 6, and the reaction separation tower 2 is further provided with a second reflux port below the distillation section 22, and one end of the reboiler 6 is connected to the second reflux port, and the other end is connected to the bottom end of the reaction separation tower 2.

[0098] In some embodiments of the present application, the mixer 3 is also connected to the stripping section 22 .

[0099] The tert-butyl alcohol generated in the first reaction section 211 can form a tert-butyl alcohol-diisobutylene azeotrope with a higher boiling point with a portion of diisobutylene, and flow downward in the tower together with diisobutylene. When it flows to the distillation section 22, the azeotrope is extracted from the side line and circulated to the mixer 3 for recycling.

[0100] In some embodiments of the present application, the device for producing diisobutylene further includes a booster pump 7 , and the mixer 3 is connected to the fifth raw material inlet 43 via the booster pump 7 .

[0101] In some embodiments of the present application, the bottom end of the contact reactor 4 is connected to the fourth raw material inlet 24 through a logistics pipeline, and a control valve 81 is provided on the logistics pipeline. A liquid level regulator 82 is connected to the contact reactor 4 below the second heat transfer section 41 and above the second reaction section 42, and the liquid level regulator 82 is communicatively connected to the control valve 81.

[0102] The liquid level regulator 82 can ensure that the liquid level in the contact reactor 4 is stable and always maintained at a position higher than the top of the second reaction section 42, so that the second reaction section 42 is always immersed in the liquid phase. When the isobutylene content in the reaction feed increases, the reaction exotherm increases, and the corresponding flow rate of the first gas phase material increases, causing the inventory of the liquid phase reactant in the contact reactor 4 to decrease, which will inevitably lead to a decrease in the liquid level of the contact reactor 4. At this time, the liquid level regulator 82 controls the opening of the valve 81 through a pneumatic or electric signal to reduce the opening of the control valve 81, thereby reducing the flow rate of the first liquid phase material, so that the liquid level can be quickly maintained at the set value; conversely, when the isobutylene content in the reaction feed decreases, the reaction exotherm decreases, and the corresponding flow rate of the first gas phase material decreases, causing the inventory of the liquid phase reactant in the contact reactor 4 to increase, which will inevitably lead to an increase in the liquid level of the contact reactor 4. At this time, the liquid level regulator 82 controls the opening of the control valve 81 through a pneumatic or electric signal to increase the opening of the control valve 81, thereby increasing the flow rate of the first liquid phase material, so that the liquid level can be quickly maintained at the set value.

[0103] The interface of the gas-liquid two phases in the contact reactor 4 is higher than the top of the second reaction section 42, so that the superposition reaction is always carried out under liquid phase conditions. In contrast, the mixed-phase bed reactor widely used in the art is basically not carried out in pure liquid phase but in gas-liquid mixed phase or even in pure gas phase. This operating condition has the defect of exposing part or all of the catalyst outside the liquid layer or there is little or no liquid phase in the reactor; it is well known to those skilled in the art that the selective superposition reaction of isobutylene is a liquid-solid reaction. Under the same conditions, the liquid mixed carbon four treated by the unit volume of catalyst is 200 to 600 times that of the gas mixed carbon four. The catalyst bed layer in the contact reactor 4 is full of liquid, which is beneficial to improve the utilization rate of the unit volume of resin catalyst and the conversion rate of the isobutylene superposition reaction. Therefore, the control valve 81 and the liquid level regulator 82 are provided, which has the advantages of high catalyst utilization and high isobutylene conversion rate.

[0104] In a second aspect, the present invention provides a method for producing diisobutylene, wherein the method for producing diisobutylene is carried out by the method described in the first aspect and Figure 1 The production device of diisobutylene shown is realized, and the production method of diisobutylene comprises the following steps:

[0105] S1: introducing a C4 raw material into the contact heat exchanger 1 through the first raw material inlet 12, and introducing a first gas phase material formed in the contact reactor 4 into the contact heat exchanger 1 through the second raw material inlet 13;

[0106] S2: introducing the second liquid phase material formed in the contact heat exchanger 1 into the mixer 3, and at the same time introducing a reaction inhibitor from the outside into the mixer 3;

[0107] S3: introducing the mixed material formed in the mixer 3 into the contact reactor 4 through the fifth raw material inlet 43;

[0108] S4: introducing the second gas phase material formed in the contact heat exchanger 1 into the distillation section 21 of the reaction separation tower 2 through the third raw material inlet 23, and introducing the first liquid phase material formed at the bottom of the contact reactor 4 into the fourth raw material inlet 24;

[0109] S5: collecting unreacted C4 raw material from the top of the reaction separation tower 2, and collecting diisobutylene from the bottom of the reaction separation tower 2.

[0110] It is easy to understand that since the chemical production process is carried out continuously, steps S1 to S5 in this application are only used as numbers and do not indicate the order of precedence.

[0111] In some embodiments of the present application, the reaction inhibitor is deoxygenated water.

[0112] Under the action of acidic catalyst, the rate of isobutylene superposition reaction is relatively fast. If it is not controlled, a large amount of trimers and tetramers will be generated. Table 5 shows the isobutylene conversion rate and superposition composition under several typical feeding conditions.

[0113]

[0114] Table 5 Isobutylene conversion and product composition under different feed and operating conditions

[0115] As can be seen from Table 5, without control, the mass fractions of trimer and tetramer in diisobutylene products are as high as 38.3% to 40.0% and 3.7% to 8.0%, respectively. In order to avoid the quality degradation or substandard products caused by excessive polymer content, certain measures must be taken to reduce the amount of polymer generated during the superposition reaction. From the mechanism of selective superposition reaction of isobutylene, it can be seen that the dimer selectivity mainly depends on the adsorption and desorption rate of isobutylene and dimer on the catalyst surface. Adding polar components such as methanol, ethanol, isopropanol, tert-butanol, and water to the raw materials can effectively reduce the adsorption of dimers on the catalyst surface. Taking the cation exchange resin catalyst as an example, these polar components are easily adsorbed on the active center of the catalyst and react with the sulfonic acid group as follows:

[0116]

[0117] The above process can effectively reduce the adsorption of diisobutylene on the catalyst surface, and due to SO3 - ROH2 + The acidity is higher than H +The activity of the resin catalyst and the polymerization reaction rate are further reduced, which is beneficial to inhibiting the formation of trimers and tetramers, so that the mass fraction of the dimer in the final polymerization product is increased to more than 80%, and the mass fraction of the tetramer is reduced to less than 0.1%, and the quality of the product is significantly improved.

[0118] When small molecular alcohols such as methanol and ethanol are used as inhibitors, the alcohol / olefin ratio is generally controlled at above 0.2, and the reaction product is mainly a mixture of 2,4,4-trimethylpentene and MTBE or ETBE; when large molecular alcohols such as isopropanol and sec-butyl alcohol are used as inhibitors, their activity in the etherification reaction with isobutylene is low, the thermodynamic equilibrium conversion rate is low, and the alcohol consumed in the etherification reaction is correspondingly reduced. Even when the alcohol / olefin ratio is as low as 0.05, there will be enough alcohol adsorbed on the active center of the catalyst to keep the reaction at a high dimerization selectivity; when tert-butyl alcohol is selected as an inhibitor, it cannot undergo etherification reaction with isobutylene due to steric hindrance, so that the final reaction product does not contain ether compounds.

[0119] Water, as a polar component, is also an inhibitor of the isobutylene polymerization reaction.

[0120] In addition, it is worth noting that water will also react with isobutylene to form tert-butyl alcohol (TBA), the reaction formula is as follows:

[0121]

[0122] The above reaction is a reversible reaction. This means that the amount of tert-butyl alcohol can be indirectly regulated by controlling the amount of water. In the practical application of this application, deoxygenated water is generally used as an inhibitor.

[0123] The present application adopts deoxygenated water and tert-butanol generated by the reversible reaction of deoxygenated water and isobutylene as the composite inhibitor of the superposition reaction, and its main advantages are: the deoxygenated water raw material is cheap and easy to obtain; it will not react with isobutylene to generate ether compounds such as MTBE, and the yield of diisobutylene in the product is high; the inhibitor content is small, and when the molar ratio of tert-butanol to isobutylene in the mixed C4 raw material is 0.05-0.10, the requirements of conversion rate and selectivity can be met; when tert-butanol is lost in the reaction system due to reasons such as the product carrying out tert-butanol, the tert-butanol content of the entire reaction system circulation can be maintained unchanged by replenishing water.

[0124] In some embodiments of the present application, the ratio of the deoxygenated water to the isobutylene in the C4 raw material is 0 to 0.30:1 in terms of molar ratio.

[0125] In some embodiments of the present application, the method for producing diisobutylene further comprises the following steps:

[0126] S6: extracting tert-butyl alcohol-diisobutylene azeotrope from the stripping section 22 and introducing the azeotrope into the mixer 3.

[0127] In some embodiments of the present application, in step S6, the tert-butanol-diisobutylene azeotrope is extracted from the distillation section 22 and then introduced into the mixer 3, and the ratio of the extracted tert-butanol to the isobutylene in the C4 raw material is 0.05-0.15:1 in terms of molar ratio.

[0128] In some embodiments of the present application, the stripping section 22 has a total of 25 to 35 plates, and the tert-butyl alcohol-diisobutylene azeotrope extraction position is located between the 11th to 21st plates in the stripping section 22 counting from top to bottom.

[0129] In some embodiments of the present application, in step S3, the mixed material formed in the mixer 3 is introduced into the contact reactor 4 through the fifth raw material inlet 43, and the mixed material is introduced into the contact reactor 4 at a temperature of 45 to 58° C. and a pressure of 0.8 to 1.2 MPa;

[0130] The catalyst provided in the second reaction section 42 is a macroporous cation exchange resin;

[0131] The operating conditions of the second reaction stage 42 are: the volume space velocity of the reaction liquid is 0.5 to 5 h -1 , reaction pressure is 0.6-1.0 MPa, and reaction temperature is the bubble point temperature of the material in the second reaction stage under the reaction pressure of the second reaction stage.

[0132] In some embodiments of the present application, in step S1, the C4 raw material is introduced into the contact heat exchanger through the first raw material inlet 12, and the C4 raw material is introduced into the contact heat exchanger under a pressure of 0.8-1.2 MPa and a temperature of 35-45° C.;

[0133] In step S2, the first gas-phase material formed in the contact reactor 4 is introduced into the contact heat exchanger through the second raw material inlet 13. The first gas-phase material is introduced into the contact heat exchanger at a pressure of 0.6-1.0 MPa and a temperature of 55-75°C.

[0134] In some embodiments of the present application, the catalyst provided in the first reaction section 211 is a macroporous cation exchange resin;

[0135] The operating conditions of the first reaction stage 211 are: the volume space velocity of the reaction liquid is 0.5 to 5 h -1 , reaction pressure is 0.4~1.0MPa, and reaction temperature is 55~75℃.

[0136] In some embodiments of the present application, the distillation section 21 has a total of 15 to 25 tower plates, and the third raw material inlet 23 is located between the 10th to 15th tower plates in the distillation section 21 from top to bottom.

[0137] In some embodiments of the present application, the first reaction section 211 has 1 to 15 catalyst beds, and the first reaction section 211 is arranged at the lower part of the 3rd to 9th tower plates counted from top to bottom in the distillation section 21 .

[0138] The present application will be further described below in conjunction with specific embodiments. It should be understood that these embodiments are intended only to illustrate the present application and are not intended to limit the scope of the present application. The experimental methods for which specific conditions are not specified in the following examples are usually measured according to national standards. If there is no corresponding national standard, then the conditions recommended by the manufacturer are followed.

[0139] Example

[0140] This embodiment first provides a production device for diisobutylene, and the production device for diisobutylene comprises:

[0141] A contact heat exchanger, wherein the contact heat exchanger has a first heat transfer section, and the contact heat exchanger has a first raw material inlet above the first heat transfer section and a second raw material inlet below the first heat transfer section;

[0142] A reaction separation tower, wherein the reaction separation tower includes a rectifying section and a stripping section arranged from top to bottom, a third raw material inlet is arranged at the rectifying section on the reaction separation tower, the top of the contact heat exchanger is connected to the third raw material inlet, the rectifying section also includes a first reaction section provided with a catalyst, the first reaction section is arranged above the third raw material inlet, the reaction separation tower is further provided with a fourth raw material inlet, and the fourth raw material inlet is arranged at the junction of the rectifying section and the stripping section;

[0143] a mixer, the mixer being in communication with a bottom of the contact heat exchanger;

[0144] A contact reactor, wherein the top end of the contact reactor is connected to the second raw material inlet, the bottom end of the contact reactor is connected to the fourth raw material inlet, a second heat transfer section and a second reaction section provided with a catalyst are arranged from top to bottom inside the contact reactor, a fifth raw material inlet is arranged above the second heat transfer section on the contact reactor, and the mixer is connected to the fifth raw material inlet.

[0145] The production device of diisobutylene also includes a condenser, a reflux tank and a reflux pump, wherein one end of the condenser is connected to the top of the reaction separation tower, and the other end is connected to the upper part of the reflux tank, the reaction separation tower is provided with a first reflux port at the upper part of the distillation section, one end of the reflux pump is connected to the bottom of the reflux tank, and the other end is connected to the first reflux port, the other end of the reflux pump is also connected to the outside, and a water diversion bucket is also provided at the bottom of the reflux tank;

[0146] The diisobutylene production device also includes a reboiler. The reaction separation tower is also provided with a second reflux port below the stripping section. One end of the reboiler is connected to the second reflux port, and the other end is connected to the bottom end of the reaction separation tower.

[0147] The mixer is also connected to the reaction separation tower.

[0148] The diisobutylene production device further comprises a booster pump, and the mixer is connected to the fifth raw material inlet via the booster pump.

[0149] The bottom end of the contact reactor is connected to the fourth raw material inlet through a logistics pipeline, and a control valve is arranged on the logistics pipeline. A liquid level regulator is connected to the contact reactor below the second heat transfer section and above the second reaction section, and the liquid level regulator is communicatively connected to the control valve.

[0150] Then,

[0151] This embodiment also provides a method for producing diisobutylene. The method for producing diisobutylene is implemented by the diisobutylene production device provided in this embodiment. The method for producing diisobutylene comprises the following steps:

[0152] Providing a C4 raw material, wherein the molar fractions of isobutylene and butene-1 are 41% and 11% respectively;

[0153] Introducing a C4 raw material into the contact heat exchanger through the first raw material inlet, and introducing a first gas phase material formed in the contact reactor into the contact heat exchanger through the second raw material inlet;

[0154] Introducing the second liquid phase material formed in the contact heat exchanger into the mixer, and simultaneously introducing a reaction inhibitor from the outside into the mixer;

[0155] introducing the mixed material formed in the mixer into the contact reactor through the fifth raw material inlet;

[0156] The second gas phase material formed in the contact heat exchanger is introduced into the distillation section through the third raw material inlet, and the first liquid phase material formed at the bottom of the contact reactor is introduced into the fourth raw material inlet;

[0157] Unreacted C4 raw material is collected from the top of the reaction separation tower, and diisobutylene is collected from the bottom of the reaction separation tower.

[0158] The reaction inhibitor is deoxygenated water.

[0159] In terms of molar ratio, the ratio of the deoxygenated water to the isobutylene in the C4 raw material is 0 to 0.30:1.

[0160] The production method of diisobutylene also includes the following steps:

[0161] The tert-butyl alcohol-diisobutylene azeotrope is extracted from the stripping section and then introduced into the mixer.

[0162] The tert-butyl alcohol-diisobutylene azeotrope is extracted from the stripping section and then introduced into the mixer. The ratio of the extracted tert-butyl alcohol to the isobutylene in the C4 raw material is 0.05-0.15:1 in terms of molar ratio.

[0163] The stripping section has 30 tower plates in total, and the tert-butyl alcohol-diisobutylene azeotrope extraction port is located between the 15th and 16th tower plates counting from top to bottom in the stripping section.

[0164] The mixed material formed in the mixer is introduced into the contact reactor through the fifth raw material inlet, and the mixed material is introduced into the contact reactor at a temperature of 45 to 58° C. and a pressure of 0.8 to 1.2 MPa;

[0165] The operating conditions of the second reaction stage are: the volume space velocity of the reaction liquid is 3h -1 , reaction pressure is 0.8 MPa, and reaction temperature is the bubble point temperature of the material in the second reaction stage at 0.8 MPa.

[0166] The C4 raw material is introduced into the contact heat exchanger through the first raw material inlet, and the C4 raw material is introduced into the contact heat exchanger under a pressure of 0.8-1.2 MPa and a temperature of 35-45° C.;

[0167] The first gas-phase material formed in the contact reactor is introduced into the contact heat exchanger through the second raw material inlet. The first gas-phase material is introduced into the contact heat exchanger at a pressure of 0.78 MPa and a temperature of 67.2°C.

[0168] The catalyst provided in the first reaction section is a macroporous cation exchange resin;

[0169] The operating conditions of the first reaction stage are: the volume space velocity of the reaction liquid is 0.5 to 5 h -1 , reaction pressure is 0.4~1.0MPa, and reaction temperature is 55~75℃.

[0170] The distillation section has a total of 20 tower plates, and the third raw material inlet is located between the 12th and 13th tower plates counting from top to bottom in the distillation section.

[0171] More specifically, the specific selection of the above parameter ranges, as well as other operating parameters are shown in Tables 6 and 7:

[0172]

[0173]

[0174] Table 6 Main equipment operating conditions

[0175]

[0176] Table 7 Material balance

[0177] The final isobutylene conversion rate in the embodiment is 97.0%, and the mass fraction of 2,4,4-trimethyl-pentene in the diisobutylene product is 93.6%.

[0178] Comparative Example 1

[0179] Comparative Example 1 uses FCC mixed C4 as polymerization raw material, and the preparation method is carried out according to the following literature: Development of products such as diisobutylene and C12 olefin separated from selective polymerization oil [J]. Total Corrosion Control, 1994(04):47-48

[0180] In Comparative Example 1, the diisobutylene product mainly contains C8 olefins, olefin components with molecular weight less than C8, trimers, and tetramers, with mass fractions of 64.82%, 5.61%, 27.57%, and 2.00%, respectively. The mass fraction of C8 olefin in the stack is only 64.82%, and there are a large number of isomers with similar boiling points in C8 olefins. The mass fraction of the target products 2,4,4-trimethyl-1-pentene and 2,4,4-trimethyl-2-pentene in the stack is only 45.34%. Compared with Comparative Example 1, the mass fraction of 2,4,4-trimethyl-pentene in the diisobutylene product of the embodiment can be increased by more than 30 percentage points.

[0181] Comparative Example 2

[0182] Comparative Example 2 uses a mixed bed reactor to prepare diisobutylene.

[0183] The embodiment can process a C4 raw material with an isobutylene molar fraction of 41% without any pretreatment; in Comparative Example 2, in order to prevent the reaction heat from vaporizing all the unreacted C4 in the mixed bed reactor, an inert component such as a butane component, a pentane component, or a hydrocracking light naphtha without olefins needs to be added to the C4 raw material so that the isobutylene content in the C4 raw material does not exceed 34%. Compared with the embodiment, Comparative Example 2 increases the energy consumption of the device by 10% to 15% due to the addition of the inert component circulating in the device.

[0184] Comparative Example 3

[0185] The raw materials of the embodiment and comparative example 3 are the same. Comparative example 3 adopts the method of returning part of the remaining mixed carbon four to the superposition reactor to control the reaction temperature rise.

[0186] In the example, the conversion rate of butene-1 is 2.1%, while in comparative example 3, the side reaction of butene-1 and isobutylene is increased by recycling butene-1 to the superposition reactor, so that the conversion rate of butene-1 is as high as 10.1%. Compared with comparative example 3, the by-products such as 2,5-dimethylhexene and 5,5-dimethylhexene generated by superposition of butene-1 and isobutylene in the example are less, thereby improving the quality of the diisobutylene product and reducing the loss of butene-1 in the C4 raw material.

[0187] Comparative Example 4

[0188] The raw materials of the embodiment and comparative example 4 are the same. Comparative example 4 adopts the method of fixed bed external circulation, a reflux branch is drawn out from the discharge port of the fixed bed superposition reactor, and a circulation cooler and a circulation pump are arranged on the reflux branch to cool and pressurize the reaction product in the reflux branch and then return it to the reactor feed port.

[0189] The heat of the superposition reaction in the embodiment is all used for mass transfer and heat transfer between the gas and liquid phases; in the comparative example 4, the reaction heat is not fully utilized, and the amount of circulating water for cooling and the power consumption of the pump are increased. Compared with the comparative example 4, the embodiment saves 6% to 12% of the energy consumption of the device.

[0190] Comparative Example 5

[0191] Comparative Example 5 adopts the method disclosed in CN209276413U.

[0192] Compared with Comparative Example 5, Example 5 avoids the situation in which a large amount of tert-butanol is injected into the tower from the outside during the start-up process of Comparative Example 5, and the tert-butanol with a high freezing point is easy to crystallize and cause the tower plate to be blocked, thereby reducing the tert-butanol consumption and operating costs and simplifying the process.

[0193] Various embodiments of the present application may be presented in the form of a range; it should be understood that the description in the form of a range is only for convenience and brevity, and should not be understood as a rigid limitation on the scope of the present application; therefore, the range description should be considered to have specifically disclosed all possible sub-ranges and single numerical values ​​within the range. For example, the range description from 1 to 6 should be considered to have specifically disclosed sub-ranges, such as from 1 to 3, from 1 to 4, from 1 to 5, from 2 to 4, from 2 to 6, from 3 to 6, etc., as well as single numbers within the range, such as 1, 2, 3, 4, 5 and 6, which apply regardless of the range. In addition, whenever a numerical range is indicated herein, it is meant to include any cited number (fractional or integer) within the indicated range.

[0194] In the present application, in the absence of contrary instructions, the directional words used, such as "upper" and "lower", are specifically the conventional implementation directions in actual chemical production. In addition, in the description of the present application specification, the terms "including", "comprising", etc. refer to "including but not limited to". Moreover, the terms "including", "comprising" or any other variants thereof are intended to cover non-exclusive inclusion, so that the process, method, article or equipment including a series of elements not only include those elements, but also include other elements not clearly listed, or also include elements inherent to such process, method, article or equipment. In the absence of more restrictions, the elements defined by the sentence "including..." do not exclude the existence of other identical elements in the process, method, article or equipment including the elements. In this article, relational terms such as "first" and "second" are only used to distinguish one entity or operation from another entity or operation, and do not necessarily require or imply that there is any such actual relationship or order between these entities or operations. In this article, "and / or" describes the association relationship of associated objects, indicating that there can be three relationships, for example, A and / or B, which can represent: A exists alone, A and B exist at the same time, and B exists alone. For the association relationship of more than three associated objects described by "and / or", it means that any one of these three associated objects can exist alone, or any at least two of them exist at the same time. For example, for A, and / or B, and / or C, it can be represented that any one of A, B, and C exists alone, or any two of them exist at the same time, or three of them exist at the same time. In this article, "at least one" refers to one or more, and "multiple" refers to two or more. "At least one", "the following at least one (individual)" or similar expressions refer to any combination of these items, including any combination of single (individual) or plural (individual). For example, "at least one (individual) of a, b, or c", or "at least one (individual) of a, b, and c", can all represent: a, b, c, ab (i.e. a and b), ac, bc, or abc, wherein a, b, and c can be single or multiple, respectively.

[0195] The above description is only a specific implementation of the present application, so that those skilled in the art can understand or implement the present application. Various modifications to these embodiments will be apparent to those skilled in the art, and the general principles defined herein can be implemented in other embodiments without departing from the spirit or scope of the present application. Therefore, the present application will not be limited to the embodiments shown herein, but will conform to the widest range consistent with the principles and novel features applied for herein.

Claims

1. A production device for diisobutylene, characterized in that: The production device of diisobutylene comprises: A contact heat exchanger, wherein the contact heat exchanger has a first heat transfer section, and the contact heat exchanger has a first raw material inlet above the first heat transfer section and a second raw material inlet below the first heat transfer section; A reaction separation tower, wherein the reaction separation tower includes a rectifying section and a stripping section arranged from top to bottom, a third raw material inlet is arranged at the rectifying section on the reaction separation tower, the top of the contact heat exchanger is connected to the third raw material inlet, the rectifying section also includes a first reaction section provided with a catalyst, the first reaction section is arranged above the third raw material inlet, the reaction separation tower is further provided with a fourth raw material inlet, and the fourth raw material inlet is arranged at the junction of the rectifying section and the stripping section; a mixer, the mixer being in communication with a bottom of the contact heat exchanger; A contact reactor, wherein the top end of the contact reactor is connected to the second raw material inlet, the bottom end of the contact reactor is connected to the fourth raw material inlet, a second heat transfer section and a second reaction section provided with a catalyst are arranged from top to bottom inside the contact reactor, a fifth raw material inlet is arranged above the second heat transfer section on the contact reactor, and the mixer is connected to the fifth raw material inlet.

2. The production device of diisobutylene according to claim 1, characterized in that: The production device of diisobutylene also includes a condenser, a reflux tank and a reflux pump, wherein one end of the condenser is connected to the top of the reaction separation tower, and the other end is connected to the upper part of the reflux tank, the reaction separation tower is provided with a first reflux port at the upper part of the distillation section, one end of the reflux pump is connected to the bottom of the reflux tank, and the other end is connected to the first reflux port, the other end of the reflux pump is also connected to the outside, and a water diversion bucket is also provided at the bottom of the reflux tank; and / or, The diisobutylene production device also includes a reboiler. The reaction separation tower is also provided with a second reflux port below the stripping section. One end of the reboiler is connected to the second reflux port, and the other end is connected to the bottom end of the reaction separation tower.

3. The production device of diisobutylene according to claim 1, characterized in that: The mixer is also connected to the stripping section.

4. The production device of diisobutylene according to claim 3, characterized in that: The diisobutylene production device further comprises a booster pump, and the mixer is connected to the fifth raw material inlet via the booster pump.

5. The production device of diisobutylene according to claim 1, characterized in that: The bottom end of the contact reactor is connected to the fourth raw material inlet through a logistics pipeline, and a control valve is arranged on the logistics pipeline. A liquid level regulator is connected to the contact reactor below the second heat transfer section and above the second reaction section, and the liquid level regulator is communicatively connected to the control valve.

6. A method for producing diisobutylene, characterized in that: The method for producing diisobutylene is realized by the diisobutylene production device according to any one of claims 1 to 5, and the method for producing diisobutylene comprises the following steps: Introducing a C4 raw material into the contact heat exchanger through the first raw material inlet, and introducing a first gas phase material formed in the contact reactor into the contact heat exchanger through the second raw material inlet; Introducing the second liquid phase material formed in the contact heat exchanger into the mixer, and simultaneously introducing a reaction inhibitor from the outside into the mixer; introducing the mixed material formed in the mixer into the contact reactor through the fifth raw material inlet; The second gas phase material formed in the contact heat exchanger is introduced into the distillation section through the third raw material inlet, and the first liquid phase material formed at the bottom of the contact reactor is introduced into the fourth raw material inlet; Unreacted C4 raw material is collected from the top of the reaction separation tower, and diisobutylene is collected from the bottom of the reaction separation tower.

7. The method for producing diisobutylene according to claim 6, characterized in that: The reaction inhibitor is deoxygenated water.

8. The method for producing diisobutylene according to claim 7, characterized in that: In terms of molar ratio, the ratio of the deoxygenated water to the isobutylene in the C4 raw material is 0 to 0.30:

1.

9. The method for producing diisobutylene according to claim 8, characterized in that: The production method of diisobutylene also includes the following steps: The tert-butyl alcohol-diisobutylene azeotrope is extracted from the stripping section and then introduced into the mixer.

10. The method for producing diisobutylene according to claim 9, characterized in that: The tert-butyl alcohol-diisobutylene azeotrope is extracted from the stripping section and then introduced into the mixer. The ratio of the extracted tert-butyl alcohol to the isobutylene in the C4 raw material is 0.05-0.15:1 in terms of molar ratio.

11. The method for producing diisobutylene according to claim 10, characterized in that: The stripping section has a total of 25 to 35 tower plates, and the tert-butyl alcohol-diisobutylene azeotrope extraction position is located between the 11th to 21st tower plates counted from top to bottom in the stripping section.

12. The method for producing diisobutylene according to claim 6, characterized in that: The mixed material formed in the mixer is introduced into the contact reactor through the fifth raw material inlet, and the mixed material is introduced into the contact reactor at a temperature of 45 to 58° C. and a pressure of 0.8 to 1.2 MPa; and / or, The catalyst provided in the second reaction stage is a macroporous cation exchange resin; and / or, The operating conditions of the second reaction stage are: the volume space velocity of the reaction liquid is 0.5 to 5 h -1 , reaction pressure is 0.6-1.0 MPa, and reaction temperature is the bubble point temperature of the material in the second reaction stage under the reaction pressure of the second reaction stage.

13. The method for producing diisobutylene according to claim 6, characterized in that: The C4 raw material is introduced into the contact heat exchanger through the first raw material inlet, and the C4 raw material is introduced into the contact heat exchanger under a pressure of 0.8-1.2 MPa and a temperature of 35-45° C.; and / or, The first gas-phase material formed in the contact reactor is introduced into the contact heat exchanger through the second raw material inlet. The first gas-phase material is introduced into the contact heat exchanger at a pressure of 0.6 to 1.0 MPa and a temperature of 55 to 75°C.

14. The method for producing diisobutylene according to claim 6, characterized in that: The catalyst provided in the first reaction stage is a macroporous cation exchange resin; and / or, The operating conditions of the first reaction stage are: the volume space velocity of the reaction liquid is 0.5 to 5 h -1 , reaction pressure is 0.4~1.0MPa, and reaction temperature is 55~75℃.

15. The method for producing diisobutylene according to claim 6, characterized in that: The distillation section has 15 to 25 tower plates in total, and the third raw material inlet is located between the 10th to 15th tower plates counted from top to bottom in the distillation section.

Images