Device and method for producing diisobutylene by taking tert-butyl alcohol as raw material

Abstract

The invention discloses a device for producing diisobutylene by taking tert-butyl alcohol as a raw material. The device comprises a tert-butyl alcohol hydrolysis reactor, a first reaction separation tower and an isobutylene superposition reactor, the method comprises the following steps: carrying out hydrolysis reaction on a tert-butyl alcohol raw material in a tert-butyl alcohol hydrolysis reactor under the action of a tert-butyl alcohol hydrolysis catalyst to generate isobutene and water; the first reaction separation tower comprises a first rectifying section at the upper part and a first stripping section at the lower part, a reaction product feeding position of the tert-butyl alcohol hydrolysis reactor is positioned between the first rectifying section and the first stripping section, and a guide-out opening is formed in the side of the lower part of the first stripping section; the first stripping section is used for pumping out diisobutylene and part of water in the first reaction separation tower, and a guide-out opening is formed in the bottom of the first stripping section and used for guiding out unreacted tertiary butanol and the other part of water. The invention also discloses a method for producing diisobutylene by taking tert-butyl alcohol as a raw material. The technological process is simplified; and the production efficiency is improved.

Description

Technical Field

[0001] The invention relates to a device and a method for producing diisobutylene by taking tert-butyl alcohol as raw material. Background Art

[0002] A large amount of tert-butyl alcohol (TBA) can be produced by direct hydration of isobutylene and co-production of propylene oxide. With the rapid development of the petrochemical industry, the output of tert-butyl alcohol continues to increase, and the market is in a state of oversupply. Converting tert-butyl alcohol into high-value diisobutylene (DIB) can further expand the application field of tert-butyl alcohol and improve its application value. Diisobutylene is composed of two isomers, 2,4,4-trimethyl-1-pentene and 2,4,4-trimethyl-2-pentene. It is mainly used as an intermediate for the production of various derivative specialty products, including octylated diphenylamine antioxidants, octylphenol, isononyl derivatives, specialty polymers, elastomers and fragrance chemicals. With the continuous development of industries such as tires, specialty polymer materials, and surfactants, the demand for diisobutylene continues to grow.

[0003] The diisobutylene product is produced by using the existing technology, firstly tert-butyl alcohol is hydrolyzed into isobutylene (IB), then the isobutylene is purified, and finally the purified isobutylene is selectively superposed into diisobutylene.

[0004] The hydrolysis reaction of tert-butyl alcohol is that tert-butyl alcohol is cracked under the action of an acidic catalyst to generate isobutylene and water. The reaction is endothermic and controlled by thermodynamic equilibrium. The reaction formula is as follows:

[0005]

[0006] Isobutylene selective polymerization refers to the process in which isobutylene is selectively polymerized into diisobutylene (2,4,4-trimethyl-1-pentene, i.e., α-DIB and 2,4,4-trimethyl-2-pentene, i.e., β-DIB) under the action of an acidic catalyst. The reaction is an exothermic reaction, and the reaction formula is as follows:

[0007]

[0008] In the selective superposition reaction of isobutylene, isobutylene is adsorbed on the active center of the catalyst and dissociates to form a carbon tetrachloride ion, which combines with another isobutylene molecule to form a carbon octahedron ion. The carbon octahedron ion can be desorbed from the active center to form diisobutylene; it can also further combine with other isobutylene molecules to form a carbon twelve ion to make the carbon chain longer. Therefore, the superposition side reaction includes the continued reaction of isobutylene (IB) and diisobutylene to form a trimer (TIB):

[0009]

[0010] The superposition side reaction also includes the continued reaction of IB and TIB to form a tetramer (TEB).

[0011] Under the action of acidic catalysts such as cation exchange resin catalysts, the rate of isobutylene superposition reaction is relatively fast. If the reaction is not controlled, a large number of trimers and tetramers will be generated. In order to inhibit the production of the above trimers and tetramers and ensure the yield of diisobutylene, polar components such as alcohols and water are injected into the catalyst bed. These polar components are adsorbed on the active center of the cation exchange resin catalyst and react with the sulfonic acid group as follows:

[0012]

[0013] Due to SO3 - ROH2 + The acidity is weak, thereby reducing the activity of the resin catalyst and the polymerization reaction rate, which can effectively reduce the production of the above-mentioned trimer and tetramer side reaction products, allowing the superposition reaction to produce more diisobutylene, which is beneficial to improving product quality.

[0014] The method disclosed in the present invention can process pure tert-butyl alcohol raw materials, and can also process tert-butyl alcohol raw materials with impurities. When processing tert-butyl alcohol raw materials with impurities, such as tert-butyl alcohol produced as a byproduct of the co-oxidation process for preparing propylene oxide, the tert-butyl alcohol raw materials generally contain various components including alcohols, aldehydes, ketones, etc., and these components and water, isobutylene, and diisobutylene generated by the hydrolysis of tert-butyl alcohol will form a variety of azeotropes under different operating pressures. These azeotropes can be calculated or calculated with the help of chemical process simulation software such as ASPEN PLUS. For example, the azeotropes and azeotropic compositions formed by tert-butyl alcohol raw materials containing impurities such as water, methanol, acetone, isobutyl alcohol, isopropyl alcohol, diisobutylene, and isobutylene at normal pressure and 1.0MPa (absolute pressure) can be shown in Table 1 and Table 2 respectively.

[0015] Table 1 Azeotropic temperature and azeotropic composition of each azeotrope at normal pressure

[0016]

[0017]

[0018] Table 2 Azeotropic temperature and azeotropic composition of each azeotrope at 1.0 MPa (absolute pressure)

[0019]

[0020] As can be seen from Table 1 and Table 2, under normal pressure and 1.0 MPa (absolute pressure), 18 and 25 azeotropes are formed respectively between water, methanol, acetone, isobutyl alcohol, isopropyl alcohol, diisobutylene, isobutylene and the tert-butyl alcohol, and when the operating pressure is different, the azeotropic composition of the azeotrope will change, such as the molar azeotropic composition of the tert-butyl alcohol in the tert-butyl alcohol-water azeotrope under normal pressure is 0.627, which is reduced to 0.580 under 1.0 MPa (absolute pressure). According to the characteristic that the azeotropic composition of the azeotrope changes with pressure, the azeotrope can be separated by the method of pressure swing distillation, such as separating water from the tert-butyl alcohol-water azeotrope.

[0021] It can also be seen from Tables 1 and 2 that water and diisobutylene, acetone, isobutanol, etc. in the reaction system can form binary or ternary heterogeneous azeotropes, so the heterogeneous azeotropic distillation method can be used to separate water from other components.

[0022] In the above non-ideal gas-liquid equilibrium system including multiple components such as alcohols, aldehydes, ketones, etc., diisobutylene has a higher volatility than water, and diisobutylene has a lower volatility than isobutylene. Summary of the invention

[0023] The present invention is made in order to at least achieve the effects of increasing the production efficiency of diisobutylene, reducing energy consumption and reducing pollution.

[0024] As one aspect of the present invention, it relates to a device for producing diisobutylene using tert-butyl alcohol as a raw material, the device comprising a tert-butyl alcohol hydrolysis reactor (71), a first reaction separation tower (62) and an isobutylene superposition reactor (72);

[0025] The tert-butyl alcohol raw material undergoes a hydrolysis reaction in a tert-butyl alcohol hydrolysis reactor (71) under the action of a tert-butyl alcohol hydrolysis catalyst to generate isobutylene and water;

[0026] The first reaction separation tower (62) comprises an upper first rectifying section (621) and a lower first stripping section (622), a first reaction section (6211) is further provided in the first rectifying section (621), a reaction product feed position of the tert-butyl alcohol hydrolysis reactor (71) is located between the first rectifying section (621) and the first stripping section (622), a lead-out port is provided at the lower side of the first stripping section (622) for extracting diisobutylene and a portion of water in the first reaction separation tower (62), and a lead-out port is provided at the bottom of the first stripping section (622) for extracting unreacted tert-butyl alcohol and another portion of water;

[0027] The unreacted isobutylene and some low-boiling azeotropes in the first reaction separation tower (62) undergo an isobutylene superposition reaction in the isobutylene superposition reactor (72).

[0028] In a specific embodiment, the device further comprises: a pretreatment tower (61) for separating light components or azeotropes with a lower boiling point in the tert-butyl alcohol raw material.

[0029] In a specific embodiment, the device further comprises: a second reaction and separation tower (65) for further reaction and separation of the bottom material of the first reaction and separation tower (62).

[0030] In a specific embodiment, the second reaction separation tower (65) comprises an upper second rectifying section (651) and a lower second stripping section (652); the feeding position of the bottom material of the first reaction separation tower (62) is located between the second rectifying section (651) and the lower second stripping section (652); a second reaction section (6511) is further provided in the second rectifying section (651); and a third reaction section (6521) is further provided in the second stripping section (652); the second reaction section (6511) and the third reaction section (6521) are used to hydrolyze tert-butanol in the bottom material of the first reaction separation tower (62) to generate isobutylene and water.

[0031] In a specific embodiment, the device further comprises: a first decanter (91) for separating the material discharged from the lower side of the first distillation section (622) to form a first oil phase and a first water phase, wherein the first oil phase comprises diisobutylene and the first water phase comprises water.

[0032] In a specific embodiment, the device further comprises: a diisobutylene separation tower (63) for further separating and purifying the diisobutylene in the first oil phase separated by the first decanter (91).

[0033] In a specific embodiment, the device further comprises: a water separation tower (64) for further separating and purifying the water in the first aqueous phase separated by the first decanter (91).

[0034] In a specific embodiment, the device further comprises: a second decanter (92) for separating the top distillate of the second reaction separation tower (65) to form a second oil phase and a second water phase, wherein the second oil phase comprises isobutylene and the second water phase comprises water;

[0035] The second aqueous phase is output to the first decanter (91) for further separation and purification of water in the second aqueous phase.

[0036] In a specific embodiment, the device further comprises: an isobutylene separation tower (66) for further separating and purifying the isobutylene in the second oil phase separated by the second decanter (92).

[0037] As another aspect of the present invention, it relates to a method for producing diisobutylene using tert-butyl alcohol as a raw material, wherein the method uses the above-mentioned device for producing diisobutylene using tert-butyl alcohol as a raw material.

[0038] In a specific embodiment, the method comprises:

[0039] The hydrolysis reaction product of tert-butyl alcohol in the tert-butyl alcohol hydrolysis reactor (71) is in the first reaction separation tower (62), and isobutylene and low-boiling azeotropes flow toward the upper part of the tower. When flowing to the catalyst bed of the first reaction section (6211), under the action of the isobutylene superposition catalyst, a reaction of selective superposition of isobutylene to generate diisobutylene occurs, and the generated diisobutylene and some high-boiling azeotropes flow toward the lower part of the tower; the unreacted isobutylene and some low-boiling azeotropes in the tower continue to flow upward and are distilled off at the top of the tower, and are transported to the isobutylene superposition reactor (72) through the fifth stream (5) for isobutylene superposition reaction;

[0040] The seventh stream (7) is drawn out from the side line of the first reaction separation tower (62), and the diisobutylene generated by the reaction in the first reaction separation tower (62) and the isobutylene superposition reactor (72), and the water partially generated by the reaction in the tert-butyl alcohol hydrolysis reactor (71) are transported to the first decanter (91) to separate the diisobutylene for further separation and purification.

[0041] In a specific embodiment, the mass flow rate ratio of the seventh stream (7) extracted from the first reaction separation tower (62) to the fourth stream (4) used as feed to the first reaction separation tower (62) is controlled to be between 0.6 and 0.9.

[0042] In a specific embodiment, the method further comprises: extracting a ninth stream (9) from the bottom of the first reaction and separation tower (62) and conveying it to a second reaction and separation tower (65) for further reaction and separation.

[0043] In a specific embodiment, the diisobutylene split ratio is the ratio of the mass flow rate of diisobutylene in the seventh logistics (7) to the mass flow rate of diisobutylene in the ninth logistics (9), and the diisobutylene split ratio is controlled in the range of 30-130, preferably 50-110, and particularly preferably 70-90; the water split ratio is the ratio of the mass flow rate of water in the seventh logistics (7) to the mass flow rate of water in the ninth logistics (9), and the water split ratio is controlled in the range of 1.25-4.50, preferably 1.50-3.50, and particularly preferably 1.75-2.50.

[0044] The effects achieved by the present invention include but are not limited to the following:

[0045] ① The tert-butyl alcohol hydrolysis and isobutylene selective superposition reaction and separation process are highly coupled together, and there is no need to use process desalted water to remove impurities in the isobutylene product, nor is there a need to circulate the tert-butyl alcohol-water mixture and the tert-butyl alcohol-water azeotrope to the tert-butyl alcohol hydrolysis reactor;

[0046] ② The use of reactive distillation, heterogeneous azeotropic distillation and pressure swing distillation methods does not require external azeotropes and inhibitors, and does not require the separated tert-butyl alcohol-water azeotrope to be recycled to the reaction system, which simplifies the process flow and reduces the number of equipment;

[0047] ③ The wastewater produced in the process of hydrolysis of tert-butyl alcohol has a low content of tert-butyl alcohol and can be directly used as reinjection water for catalytic cracking devices or directly discharged to a sewage treatment plant for treatment, thus avoiding the complicated measures adopted in the prior art of first decomposing esters in the wastewater into alcohols by hydrogenolysis and then separating alcohols from water by coagulation, thus simplifying the process flow;

[0048] ④ Isobutylene is first subjected to a selective superposition reaction in the first reaction separation tower, and then the remaining isobutylene continues to react in the isobutylene superposition reactor. The reaction temperature rise is easy to control, and there is no need to use a fixed bed external circulation method such as the one disclosed in CN107827694A to control the temperature rise, which simplifies the process and improves the utilization rate of the catalyst in the isobutylene superposition reactor;

[0049] ⑤ Using water and tert-butyl alcohol that are azeotropic with light hydrocarbons such as isobutylene to replace the tert-butyl alcohol from the outside in the prior art as the composite inhibitor for the superposition reaction can save the inhibitor storage facilities, inhibitor injection facilities, and inhibitor separation facilities set up in the prior art, reduce operating costs, and simplify the process;

[0050] ⑥ Most of the water generated by the reaction in the tert-butanol hydrolysis reactor is extracted from the side line of the first reaction separation tower, thereby increasing the tert-butanol content in the feed of the second reaction separation tower and reducing the water content in the feed of the second reaction separation tower, thereby increasing the rate of the tert-butanol hydrolysis reaction in the second reaction separation tower and reducing the amount of the tert-butanol hydrolysis catalyst;

[0051] ⑦ All the heat released by the selective superposition reaction of isobutylene is used for the separation of light and heavy components, thus reducing the energy consumption of the device;

[0052] ⑧ While producing diisobutylene, high-purity isobutylene that meets market demand can be produced as needed. BRIEF DESCRIPTION OF THE DRAWINGS

[0053] Figure 1 : Schematic diagram of the device and process flow for producing diisobutylene using tert-butyl alcohol as raw material.

[0054] In the figure: 61-pretreatment tower; 62-first reaction and separation tower; 621-first rectification section; 6211-first reaction section; 622-first stripping section; 63-diisobutylene separation tower; 64-water separation tower; 65-second reaction and separation tower; 651-second rectification section; 6511-second reaction section; 652-second stripping section; 6521-third reaction section; 66-isobutylene separation tower; 71-tert-butyl alcohol hydrolysis reactor; 72-isobutylene superposition reactor; 81-first cooler; 82-second cooler; 83-third cooler; 91-first decanter; 92-second decanter. DETAILED DESCRIPTION

[0055] The inventors prepared a device for preparing polymerization-grade isobutylene by hydrolyzing tert-butyl alcohol with reference to CN 218393609 U, which includes a tert-butyl alcohol refining tower, a first catalytic distillation tower, a second catalytic distillation tower, a gas production compressor, an isobutylene heavy removal tower, a water washing tower, and an isobutylene light removal tower connected in sequence, for the conversion of tert-butyl alcohol. Impurities such as alcohols contained in the produced isobutylene product need to be removed by process desalted water from the outside, which not only consumes a large amount of process desalted water, but also increases a large amount of alcohol-containing wastewater.

[0056] The inventors conducted experiments with reference to CN106336601A. The COD content in the stream a (wastewater) produced during the hydrolysis of tert-butyl alcohol was 9.34×10 4 mg / L, and the mass fraction of alcohols in logistics a is 1.95%, ethers 0.92%, esters 1.13%, aldehydes and ketones 0.08%, and olefins 0.27%. Due to the high impurity content in the wastewater of logistics a, it cannot be directly transported to a sewage treatment plant for treatment. It is necessary to first decompose the esters in the wastewater into alcohols through hydrogenolysis, and then separate the alcohols from water through coagulation and other complex measures to treat the wastewater, which greatly increases the equipment and operating costs.

[0057] The inventor conducted an experiment with reference to US4423271A and adopted the tert-butyl alcohol hydrolysis method to prepare high-purity isobutylene. The tert-butyl alcohol raw material is first introduced into the tert-butyl alcohol hydrolysis reactor R through pipeline 1, and the reaction product enters the K1 tower, isobutylene is separated at the top of the K1 tower, and the tert-butyl alcohol-water mixture is separated at the bottom of the K1 tower. A part of the tert-butyl alcohol-water mixture returns to the tert-butyl alcohol hydrolysis reactor R, and the other part enters the K2' tower. After the impurities such as diisobutylene are separated at the top of the K2' tower, the mixture at the bottom of the K2' tower enters the K2 tower, and the tert-butyl alcohol-water azeotrope and waste water are separated at the top and bottom of the K2 tower, respectively, and the separated tert-butyl alcohol-water azeotrope are all returned to the tert-butyl alcohol hydrolysis reactor R. The total flow of the tert-butyl alcohol-water mixture and the tert-butyl alcohol-water azeotrope circulating to the tert-butyl alcohol hydrolysis reactor R is 6.5 to 16.0 times the flow of the tert-butyl alcohol raw material 1, resulting in large equipment size and high energy consumption.

[0058] In the prior art, the dehydration of tert-butyl alcohol and the selective superposition of isobutylene are two independent parts. The process flow used to produce diisobutylene is complicated and the energy consumption is too high. For example, the selective superposition of isobutylene requires the installation of an inhibitor injection system and an inhibitor separation system, which makes the process too long. The heat released by the selective superposition reaction of isobutylene cannot be used for the separation of light and heavy components, resulting in excessive energy consumption.

[0059] In view of the above, the inventors made the present invention after further research and development.

[0060] Brief description of the invention

[0061] The tert-butyl alcohol raw material is transported to the pretreatment tower (61) in the device by the first stream (1). The function of the pretreatment tower (61) is to separate the light components or azeotropes with a relatively low boiling point in the tert-butyl alcohol raw material, such as acetone-methanol binary azeotropes, acetone-methanol-water ternary azeotropes (the boiling points of the azeotropes are shown in Tables 1 and 2), so as to avoid the light components entering the device and causing an increase in the load of the reactor and other equipment, thereby reducing the equipment size and energy consumption, reducing the generation of side reaction products, and improving the product purity. Under the action of fractionation in the pretreatment tower (61), the light components or azeotropes with a relatively low boiling point in the tert-butyl alcohol raw material flow upward in the tower and are distilled out from the top of the tower as the first product, and are output to the outside of the device through the second stream (2); the tert-butyl alcohol raw material from which the first product is removed flows downward in the tower and is separated from the bottom of the tower, and is output to the tert-butyl alcohol hydrolysis reactor (71) through the third stream (3). The first product can be output from the device alone, or can be mixed with the second product or the third product described later and then output from the device; the first product can be sold as an intermediate product or further processed.

[0062] The operating conditions of the pretreatment tower (61) are as follows: the pretreatment tower (61) consists of a distillation section and a stripping section, the distillation section has 5 to 25 trays, and the stripping section has 15 to 35 trays; the tower top operating pressure is 0.3 to 1.0 MPa, the tower top operating temperature is 45 to 75° C., the tower bottom operating temperature is 70 to 145° C., and the reflux ratio (the ratio of the reflux liquid flow rate returning to the tower from the tower top to the tower top product flow rate) is 1.0 to 50.0.

[0063] In the device disclosed in the present invention, the pretreatment tower (61) is an optional device, and whether to set it up can be determined according to specific circumstances. For example, when the impurities in the tert-butyl alcohol raw material meet the preset conditions, the pretreatment tower (61) may not be set up.

[0064] Although conventional components of the device or equipment such as booster pumps, reflux pumps, condensers, reboilers, heat exchangers, reflux tanks, buffer tanks, regulating valves and evaporators are not described in this specification and schematic diagrams, they are obviously conventional components of the device or equipment that are well known to people in the industry.

[0065] After the tert-butyl alcohol raw material is sent to the tert-butyl alcohol hydrolysis reactor (71) by the third stream (3), it undergoes hydrolysis reaction under the action of the tert-butyl alcohol hydrolysis catalyst to generate isobutylene and water. The catalyst in the tert-butyl alcohol hydrolysis reactor (71) can be selected from an acidic cation exchange resin catalyst, a fluoride-treated beta zeolite catalyst, or a fluoride-treated clay catalyst, etc., preferably an acidic cation exchange resin catalyst; the tert-butyl alcohol hydrolysis reactor (71) can adopt a suitable reactor form, for example, it can be a fixed bed reactor, an expanded bed reactor or a tubular reactor, preferably a tubular reactor. The total number of reactors can be selected from 1, 2 or 3, preferably 2. The reactors can be used in series or in parallel in the device as needed. By adjusting the number of reactors online, the reactor inlet temperature and other measures, the single-pass conversion rate of tert-butyl alcohol in the tert-butyl alcohol hydrolysis reactor (71) can be controlled at 40% to 95%. The reaction product of the tert-butyl alcohol hydrolysis reactor (71) enters the first reaction separation tower (62) through the fourth stream (4) and is further reacted and separated in the tower.

[0066] The inlet temperature of the tert-butyl alcohol hydrolysis reactor (71) is 60-110°C, the inlet pressure is 0.2-1.0 MPa, and the liquid hourly volume space velocity is 0.5-5.0 h -1 .

[0067] The reaction product feed position of the tert-butanol hydrolysis reactor (71) transported by the fourth logistics (4) divides the first reaction separation tower (62) into two parts: the first distillation section (621) is above the feed position, and the first stripping section (622) is below the feed position. A first reaction section (6211) is also provided in the first distillation section (621). Under the action of fractionation, isobutylene and low-boiling azeotropes, such as isobutylene-water azeotrope, etc., flow toward the upper part of the tower. When flowing to the catalyst bed of the first reaction section (6211), under the action of the isobutylene stacking catalyst, a selective stacking reaction of isobutylene to generate diisobutylene occurs. The generated diisobutylene and some high-boiling azeotropes, such as tert-butyl alcohol-diisobutylene azeotrope and isobutyl alcohol-diisobutylene azeotrope, flow toward the lower part of the tower; unreacted isobutylene and some low-boiling azeotropes, such as water-isobutylene azeotrope and methanol-isobutylene azeotrope, etc., continue to flow upward and are distilled off at the top of the tower, and are transported to the isobutylene stacking reactor (72) through the fifth stream (5) for isobutylene stacking reaction.

[0068] The seventh stream (7) is a stream extracted from the side of the first reaction separation tower (62), and mainly contains diisobutylene produced by the reaction in the first reaction section (6211) and the isobutylene superposition reactor (72), and water partially produced by the reaction in the tert-butyl alcohol hydrolysis reactor (71).

[0069] The ninth stream (9) is the stream extracted from the bottom of the first reaction separation tower (62), and mainly contains the tert-butanol that has not reacted in the tert-butanol hydrolysis reactor (71), and another part of the water generated by the reaction in the tert-butanol hydrolysis reactor (71). The stream is transported to the second reaction separation tower (65) for further reaction and separation.

[0070] The bottom material of the first reaction separation tower (62) contains unreacted tert-butyl alcohol and part of the reaction water (less than 18.1% to 44.4% of the total amount of reaction water), which is sent to the second reaction separation tower (65) via the ninth logistics (9) for further reaction and separation.

[0071] The first reaction separation tower (62) also receives the top material from the isobutylene separation tower (66), the main component of which is isobutylene, and is sent to the first rectification section (621) via the fifteenth stream (15). Under the action of fractionation, the isobutylene from the fifteenth stream (15) rises to the first reaction section (6211), and undergoes a selective superposition reaction under the action of the catalyst to produce diisobutylene.

[0072] The bottom material of the first reaction separation tower (62) contains unreacted tert-butyl alcohol and part of the water generated by the reaction (this part of the water generated by the reaction accounts for 18.1% to 44.4% of the total amount of water generated by the reaction, such as 18.1%, 28.1%, 38.1%, 44.4%, etc. of the total amount of water generated by the reaction), which is sent to the second reaction separation tower (65) via the ninth logistics (9) for further reaction and separation.

[0073] The operating conditions of the first reaction separation tower (62) are as follows: a tower top temperature of 40 to 80°C, a tower bottom temperature of 100 to 160°C, an operating pressure of 0.4 to 1.0 MPa, and a reflux ratio of 0.5 to 10.0; the side line extraction ratio is controlled at 0.6 to 0.9, and the side line extraction ratio is the ratio of the mass flow rate of the seventh logistics (7) to the mass flow rate of the fourth logistics (4); the first distillation section (621) is provided with 10 to 30 plates, the first stripping section (622) is provided with 15 to 35 plates, the first reaction section (6211) has a total of 1 to 15 catalyst beds, the catalyst bed is filled with an acidic cation exchange resin catalyst, and the catalyst bed liquid hourly volume space velocity is 0.5 to 3.0 h -1The first reaction section (6211) is located below any tray between the 3rd and 6th trays in the first rectifying section (621); the inlet position of the fifteenth stream (15) is below the bottom of the first reaction section (6211) and is 3 to 6 trays away from the bottom of the first reaction section (6211); the inlet position of the sixth stream (6) is located below any tray between the 2nd and 6th trays in the first stripping section (622); the sideline extraction position of the seventh stream (7) is located below any tray between the 2nd and 34th trays in the first stripping section (622), such as below the 8th, 21st, and 33rd trays. More preferably, the sideline extraction position is located below the tray in the stripping section whose ki value is closest to 1.0, wherein ki is represented by formula (1):

[0074]

[0075] In formula (1):

[0076] k i ─The gas-liquid equilibrium constant of diisobutylene on the i-th plate;

[0077] y i ─ The gas phase equilibrium composition of diisobutylene on the i-th plate;

[0078] x i ─ The equilibrium composition of diisobutylene liquid phase on the i-th plate;

[0079] In the device disclosed in the present invention, the diisobutylene split ratio is the ratio of the mass flow rate of diisobutylene in the seventh logistics (7) to the mass flow rate of diisobutylene in the ninth logistics (9), and the water split ratio is the ratio of the mass flow rate of water in the seventh logistics (7) to the mass flow rate of water in the ninth logistics (9). The greater the reflux ratio of the first reaction separation tower (62), the closer the side line extraction position is to the lower part of the tower, and the greater the side line extraction ratio, the greater the diisobutylene split ratio and the water split ratio, the greater the mass of diisobutylene in the seventh logistics (7), and the higher the mass fraction of tert-butyl alcohol in the ninth logistics (9). Accordingly, the diisobutylene yield in the diisobutylene product is higher and the organic impurity content in the wastewater is lower, but the size of the related equipment increases and the energy consumption of the device increases. Therefore, the present invention comprehensively optimizes the product yield and the energy consumption of the device, and controls the diisobutylene split ratio to be 30-130, preferably 50-110, and particularly preferably 70-90, and controls the water split ratio to be 1.25-4.50, preferably 1.50-3.50, and particularly preferably 1.75-2.50 by adjusting the reflux ratio of the first reaction separation tower (62), the side line extraction position, and the side line extraction ratio.

[0080] The top material of the first reaction separation tower (62) is condensed by a condenser and pressurized by a reflux pump (not shown in the figure) and then enters the isobutylene superposition reactor (72) through the fifth logistics (5). The isobutylene superposition reactor (72) is equipped with an acidic cation exchange resin catalyst. Under the action of the catalyst, isobutylene undergoes a superposition reaction to generate diisobutylene. The isobutylene superposition reactor (72) can adopt a suitable reactor form, for example, it can be a fixed bed reactor, an expanded bed reactor, a mixed bed reactor or a tubular reactor. Preferably, a fixed bed reactor is selected. The total number of reactors can be 1, 2 or 3, preferably 2. The reactors can be used in series or in parallel as needed. The single-pass conversion rate of isobutylene in the isobutylene superposition reactor (72) can be adjusted by adjusting the number of reactors online, the reactor inlet temperature, the fifth logistics flow rate and other measures. The reaction product of the isobutylene superposition reactor (72) enters the first reaction separation tower (62) through the sixth logistics (6).

[0081] The inlet temperature of the isobutylene superposition reactor (72) is 45-65°C, the inlet pressure is 0.6-2.0 MPa, and the liquid hourly volume space velocity is 0.1-3.0 h -1 .

[0082] In addition, side reactions such as the polymerization of isobutylene and diisobutylene to form trimer (TIB) and the etherification of isobutylene and methanol to form MTBE may also occur in the first reaction separation tower (62) and / or the isobutylene polymerization reactor (72). Under the operating conditions of the first reaction separation tower (62) and the isobutylene polymerization reactor (72), the amount of these side reaction products is only 0.0001 to 0.001 of the amount of diisobutylene produced, so these side reaction products can be ignored or recovered as the second product or the third product in subsequent equipment.

[0083] It is worth mentioning that, since the alcohols carried in the tert-butyl alcohol raw material, water and isobutylene generated by the hydrolysis reaction of tert-butyl alcohol, etc. will form a variety of azeotropes (see Table 1 and Table 2), under the action of fractionation in the first reaction separation tower (62), some azeotropes with lower boiling points, such as water-isobutylene azeotrope, methanol-isobutylene azeotrope or water-tert-butyl alcohol azeotrope, will flow upward together with isobutylene. When flowing to the first reaction section (6211), isobutylene undergoes a superposition reaction under the action of the catalyst. At the same time, polar components such as water, methanol or tert-butyl alcohol in the above azeotropes can cover the active center of the catalyst and serve as inhibitors for the production of pseudo trimers and tetramers. Afterwards, these polar components leave the top of the first reaction separation tower (62) together with the unreacted isobutylene and enter the isobutylene superposition reactor (72) together to continue to serve as inhibitors for the production of pseudo trimers and tetramers. It can be seen that the method disclosed in the present invention does not have to separately set up facilities for transporting external polar components such as water and tert-butyl alcohol to the stacking device like other methods, which simplifies the process and reduces equipment and operating costs.

[0084] Furthermore, the greater the distillate volume of the first reaction separation tower (62) (equivalent to the flow rate of the fifth logistics (5)), the higher the content of polar components entering the isobutylene superposition reactor (72), the more polar components cover the active centers of the catalyst, the less the amount of trimers and tetramers produced, but the greater the energy consumption of the device.

[0085] The material drawn from the side line of the first reaction separation tower (62) can be in liquid phase or gas phase. This material is output to the first cooler (81) through the seventh stream (7), cooled to 5-45°C, and then output to the first decanter (91) through the eighth stream (8). Another preferred solution disclosed in the present invention is that this material can also be output to the reboiler of the pretreatment tower (61) or the reboiler of the diisobutylene separation tower (63) through the seventh stream (7) to be used as a reboiler heat source, and then output to the first cooler (81) to form a distillation heat coupling process and further save energy.

[0086] The first decanter (91) is mainly used to receive materials from the eighth logistics (8), and at the same time receive materials from the thirteenth logistics (13) and the eighteenth logistics (18). The first decanter (91) is a decanter or a phase separator or a membrane separator, and the materials are separated into a first oil phase and a first water phase in the first decanter (91). The first oil phase is mainly composed of diisobutylene, and also contains a small amount of impurities such as water, isobutylene, and methanol. The diisobutylene is further purified by the nineteenth logistics (19) to the diisobutylene separation tower (63). The first water phase is mainly composed of water, and also contains a small amount of diisobutylene, methanol, and other components. The water is further purified by the twenty-first logistics (21) to the water separation tower (64).

[0087] The operating temperature of the first decanter (91) is 5-45°C, and the operating pressure is 0.4-1.0 MPa.

[0088] The first oil phase enters the diisobutylene separation tower (63) from the first decanter (91) via the nineteenth logistics (19). The purpose of setting the diisobutylene separation tower (63) is to separate diisobutylene from impurities such as water, isobutylene, methanol, etc., to ensure that the mass fraction of diisobutylene in the diisobutylene product logistics after separation is not less than 99.5%. The boiling points of the azeotropes formed between water, isobutylene and methanol are lower than that of pure diisobutylene, and thus they move to the upper part of the tower under the action of fractionation and are distilled out from the top of the diisobutylene separation tower (63), and are sent to the second cooler (82) through the seventeenth stream (17) and cooled to 5-45° C., and then are transported to the first decanter (91) through the eighteenth stream (18); the diisobutylene product from which impurities such as water, isobutylene and methanol have been removed and the mass fraction of diisobutylene is not less than 99.5% is taken out from the bottom of the diisobutylene separation tower (63), and is directly or after heat exchange or cooling (not shown) as a product output device through the twentieth stream (20).

[0089] The operating conditions of the diisobutylene separation tower (63) are as follows: the diisobutylene separation tower (63) consists of a rectifying section and a stripping section, the rectifying section has 5 to 15 trays, and the stripping section has 10 to 25 trays; the tower top operating pressure is 0.1 to 0.5 MPa, the tower top operating temperature is 5 to 45° C., the tower bottom operating temperature is 85 to 205° C., and the reflux ratio is 0.5 to 60.0.

[0090] In the device disclosed in the present invention, the diisobutylene separation tower (63) is an optional device, and whether to set it up can be determined according to specific circumstances. For example, when the tert-butyl alcohol raw material does not contain impurities, the diisobutylene separation tower (63) may not be set up.

[0091] The first water phase enters the water separation tower (64) from the first decanter (91) through the twenty-first logistics (21). The purpose of setting the water separation tower (64) is to remove a small amount of diisobutylene, methanol and other components in the water to ensure that the mass fraction of water in the bottom material after separation is not less than 99.9%. The boiling points of the azeotropes formed by diisobutylene, water, methanol and the like are lower than that of pure water, so they move to the upper part of the water separation tower (64) under the action of fractional distillation and are distilled out at the top of the tower. Finally, they are cooled to 30-50° C. by the tower top condenser (not shown in the figure) and then output as the second product from the twenty-second logistics (22). The second product can be output from the device alone or mixed with the first product or the third product described later. The second product can be sold or further processed as an intermediate product. The bottom material from which components such as diisobutylene and methanol have been removed and the mass fraction of water is not less than 99.9% is output from the bottom of the water separation tower (64) as the first wastewater directly or after heat exchange or cooling (not shown) through the twenty-third logistics (23). The first wastewater can be used as injection water for atmospheric and vacuum pressure, catalytic cracking, hydrogenation and other devices or directly discharged to a sewage treatment plant for treatment.

[0092] The operating conditions of the water separation tower (64) are as follows: the water separation tower (64) consists of a rectifying section and a stripping section, the rectifying section has 10 to 25 trays, and the stripping section has 15 to 30 trays; the tower top operating pressure is 0.1 to 0.5 MPa, the tower top operating temperature is 55 to 105° C., the tower bottom operating temperature is 105 to 165° C., and the reflux ratio is 0.5 to 60.0.

[0093] In the device disclosed in the present invention, the water separation tower (64) is an optional device, and whether to set it up can be determined according to specific circumstances. For example, when the tert-butyl alcohol raw material does not contain impurities, the water separation tower (64) may not be set up.

[0094] In the first reaction separation tower (62), water, diisobutylene, tert-butyl alcohol, etc. form a highly non-ideal gas-liquid equilibrium system. In the presence of these water, diisobutylene is more volatile than water, so the content of diisobutylene in the bottom of the tower is less, so that under the action of fractionation, the bottom material of the first reaction separation tower (62) mainly contains unreacted tert-butyl alcohol and a small amount of reaction generated water. This stream of material is sent to the second reaction separation tower (65) through the ninth stream (9) for further reaction and separation. The second reaction separation tower (65) includes two parts: the second distillation section (651) is above the feeding position of the ninth stream (9), and the second stripping section (652) is below the feeding position of the ninth stream (9). A second reaction section (6511) is also provided in the second distillation section (651), and a third reaction section (6521) is also provided in the second stripping section (652). Under the action of fractionation, azeotropes or mixtures with lower boiling points, such as tert-butyl alcohol-acetone azeotropes, flow upward. When flowing to the catalyst bed of the second reaction section (6511), the tert-butyl alcohol in these azeotropes or mixtures with lower boiling points undergoes hydrolysis reaction under the action of the tert-butyl alcohol hydrolysis catalyst to generate isobutylene and water. At the same time, some azeotropes or mixtures with higher boiling points, such as tert-butyl alcohol-water azeotropes, flow downward. When flowing to the catalyst bed of the third reaction section (6521), the tert-butyl alcohol in these azeotropes or mixtures with higher boiling points undergoes hydrolysis reaction under the action of the tert-butyl alcohol hydrolysis catalyst to also generate isobutylene and water. The isobutylene and water generated in the second reaction section (6511) and the third reaction section (6521) continue to move to the upper and lower parts of the tower respectively. Isobutylene and azeotropes or mixtures with lower boiling points moving to the upper part of the tower are distilled from the top of the second reaction separation tower (65), and are sent to the third cooler (83) through the tenth stream (10). After being cooled to 5-45°C in the third cooler (83), they are transported to the second decanter (92) through the eleventh stream (11); water and azeotropes or mixtures with higher boiling points moving to the lower part of the tower leave the bottom of the second reaction separation tower (65) and are discharged as the second wastewater. The mass fraction of water in the second wastewater is greater than 0.995, and the mass fraction of other components is not greater than 0.005. The second wastewater can be directly or after heat exchange or cooling (not shown) and then output from the fourteenth stream (14). The second wastewater can be used as water injection for catalytic cracking devices or directly discharged to a sewage treatment plant for treatment, or can be mixed with the first wastewater in a certain proportion and discharged to a sewage treatment plant after reaching the discharge index required by the sewage treatment plant.

[0095] Since most of the water generated by the reaction in the tert-butanol hydrolysis reactor (71) is extracted from the side line of the first reaction separation tower (62), the tert-butanol content in the feed of the second reaction separation tower (65) is increased and the water content in the feed of the second reaction separation tower (65) is reduced, thereby increasing the rate of the tert-butanol hydrolysis reaction in the second reaction separation tower (65), reducing the amount of tert-butanol hydrolysis catalyst in the second reaction section (6511) and the third reaction section (6521), and reducing the energy consumption of the device.

[0096] The operating conditions of the second reaction separation tower (65) are as follows: the tower top temperature is 45-85°C, the tower bottom temperature is 120-200°C, the operating pressure is 0.5-1.0 MPa, and the reflux ratio is 0.5-12.5; the second rectifying section (651) is provided with 15-35 tower plates, the second stripping section (652) is provided with 20-40 tower plates, the second reaction section (6511) and the third reaction section (6521) are provided with 2-8 and 3-10 catalyst beds respectively, the catalyst in the catalyst bed can be a fluoride-treated β zeolite catalyst or a fluoride-treated clay catalyst, preferably a fluoride-treated β zeolite catalyst; the catalyst bed liquid hourly volume space velocity is 0.5-10.0h -1 , 0.2~15.0h -1 .

[0097] The second reaction section (6511) is located below any tower plate between the 12th and 32nd tower plates counting from top to bottom in the second distillation section (651); the third reaction section (6521) is located below any tower plate between the 3rd and 15th tower plates counting from top to bottom in the second stripping section (652).

[0098] The second decanter (92) is mainly used to receive the material from the eleventh stream (11). The second decanter (92) is a decanter or a phase separator or a membrane separator, and the material is separated into a second oil phase and a second water phase in the second decanter (92). The second oil phase is mainly composed of isobutylene, and also contains a small amount of water, diisobutylene, isopropanol, isobutanol and other impurities. It is sent to the isobutylene separation tower (66) through the twelfth stream (12) to further purify the isobutylene. The second water phase is mainly composed of water, and also contains a small amount of diisobutylene, isopropanol, isobutanol and other impurities. It is sent to the first decanter (91) through the thirteenth stream (13) for further treatment.

[0099] The operating temperature of the second decanter (92) is 5-45°C, and the operating pressure is 0.5-1.5 MPa.

[0100] The second oil phase enters the isobutylene separation tower (66) from the second decanter (92) via the twelfth stream (12). The purpose of setting the isobutylene separation tower (66) is to remove impurities such as diisobutylene, isopropanol, and isobutanol in the isobutylene, and to ensure that the mass fraction of isobutylene in the fifteenth stream (15) after separation is not less than 99.5%. The boiling point of isobutylene is lower than that of impurities such as diisobutylene, isopropanol, and isobutanol, so it moves to the upper part of the tower under the action of fractionation, and is distilled from the top of the isobutylene separation tower (66), and is transported to the first reaction separation tower (62) via the fifteenth stream (15) to carry out the reaction of isobutylene superposition into diisobutylene; impurities such as diisobutylene, isopropanol, and isobutanol are separated from the bottom of the isobutylene separation tower (66) as the third product, and are directly or after heat exchange or cooling (not shown in the figure) are output from the sixteenth stream (16) to the output device. The third product can be output from the device alone, or can be mixed with the first product or the second product and then output from the device; the third product can be sold as an intermediate product or further processed.

[0101] The operating conditions of the isobutylene separation tower (66) are as follows: the isobutylene separation tower (66) consists of a rectifying section and a stripping section, the rectifying section has 10 to 20 plates, and the stripping section has 15 to 30 plates; the tower top operating pressure is 0.5 to 1.5 MPa, the tower top operating temperature is 45 to 75° C., the tower bottom operating temperature is 105 to 215° C., and the reflux ratio is 0.5 to 5.0.

[0102] In the device disclosed in the present invention, the mass fraction of isobutylene in the fifteenth logistics (15) is not less than 99.5%, so part or all of the material of the fifteenth logistics (15) can be used as a high-purity isobutylene product through the fifteenthA logistics (15A) output device and used for sale.

[0103] In summary, the device and method for producing diisobutylene using tert-butyl alcohol as raw material disclosed in the present invention, the water and isobutylene obtained from the tert-butyl alcohol hydrolysis reactor are sent to the first reaction separation tower, and light and heavy separation and isobutylene selective superposition reaction are carried out in the first reaction separation tower to obtain a mixture of diisobutylene and unreacted tert-butyl alcohol, the diisobutylene is extracted from the side line of the first reaction separation tower and is further purified before exiting the device, and the unreacted tert-butyl alcohol mixture is separated from the bottom of the first reaction separation tower after removing most of the water generated by the reaction and is sent to the second reaction separation tower to continue the hydrolysis reaction, and the isobutylene generated by the hydrolysis reaction is sent to the first reaction separation tower for selective superposition reaction, the process highly couples the hydrolysis of tert-butyl alcohol with the selective superposition of isobutylene, and the heat released by the selective superposition reaction of isobutylene is all used for the light and heavy separation of the first reaction separation tower, thereby reducing the energy consumption of the device. The device and method disclosed in the present invention can also produce the first product, the second product, and the third product as needed. The first product, the second product, and the third product can be sold or further processed as intermediate products, and can be exported from the device separately, or can be exported from the device after being mixed in a certain proportion or all. The device and method disclosed in the present invention can also produce the first wastewater and the second wastewater, which have a low content of tert-butyl alcohol and can be directly used as reinjection water for devices such as catalytic cracking or directly discharged to a sewage treatment plant for treatment, avoiding the use of other devices to first decompose esters in the wastewater into alcohols by hydrogenolysis, and then separate alcohols from water by condensation and other complex measures, thereby reducing equipment and operating costs. By adopting methods such as reactive distillation, heterogeneous azeotropic distillation and pressure-swing distillation, no external entrainer is required, and the tert-butyl alcohol-water azeotrope obtained by separation does not need to be recycled to the reaction system, further reducing the energy consumption of the device. The device and method disclosed in the present invention can also produce high-purity isobutylene that meets market demand as required.

[0104] The following is an illustrative example of the implementation process of the present invention.

[0105] Example 1

[0106] The temperature of the tert-butyl alcohol raw material is 40° C., the pressure is 0.60 MPa.A, and the flow rate is 6250.0 kg / h. The tert-butyl alcohol raw material is used as the raw material to produce diisobutylene using the device and method disclosed in the present invention.

[0107] Example 1 Reference Figure 1 For the process shown, the operating parameters of the main equipment during the production process can be found in Table 3.

[0108] Table 3 Specific operating parameters of the main equipment in Example 1

[0109]

[0110]

[0111] The main logistics flows and compositions are shown in Tables 4, 5 and 6.

[0112] Table 4 Flow and composition of main logistics

[0113]

[0114] Table 5 Flow and composition of major logistics (continued)

[0115]

[0116] Table 6 Flow and composition of major logistics (continued)

[0117]

[0118]

[0119] Under the above operating conditions, the energy consumption of the device in Example 1 is 167 kgoe / t diisobutylene product.

[0120] From Table 4, Table 5 and Table 6, we can see that:

[0121] In Example 1, 4370.21 kg / h of diisobutylene product can be produced, wherein the mass fraction of diisobutylene is 99.7313%. Example 1 also produces 96.00 kg / h of the first product, 30.60 kg / h of the second product, and 107.95 kg / h of the third product, wherein the mass fraction of acetone in the first product is 97.5586%, which can be used as a raw material for producing pure acetone products; the mass fraction of methanol in the second product is 97.6075%, which can be used as a raw material for producing pure methanol products; the mass fraction of diisobutylene in the third product is 49.5372%, which can be used as a blending component for producing gasoline for automobiles.

[0122] In Example 1, 912.49 kg / h of first wastewater and 732.75 kg / h of second wastewater are also produced, wherein the mass fraction of water in the first wastewater is 100.00%, which can be used as water injection for the atmospheric and vacuum desalination device; the mass fraction of water in the second wastewater is 99.6842%, which can be used as washing water for the light gasoline etherification device. The mass fraction of water in the mixed wastewater after the first wastewater and the second wastewater are completely mixed is 99.8594%, which can be directly discharged to the sewage treatment plant for treatment.

[0123] In the fifth logistics (5) of Example 1, the mass fraction of water is 6.5502% and the mass fraction of methanol is 0.6972%. These polar substances can be used as inhibitors of the isobutylene polymerization reaction in the isobutylene polymerization reactor (72), thereby eliminating the inhibitor storage facilities, inhibitor injection facilities, and inhibitor separation facilities provided in the prior art.

[0124] In Example 1, it is not necessary to use process desalted water to remove impurities in the isobutylene product, and the tert-butanol-water mixture and the tert-butanol-water azeotrope are not recycled to the tert-butanol hydrolysis reactor. The heat released by the selective superposition reaction is all used for separation of light and heavy components.

[0125] Embodiment 2 to Embodiment 6

[0126] In Examples 2 to 6, the distillate volume of the first reaction separation tower (62), i.e., the flow rate of the fifth logistics (5), is changed respectively. Other parameters are the same as those in Example 1.

[0127] Table 7 Changes in relevant parameters when changing the fifth logistics flow

[0128]

[0129] Note: The isobutylene single-pass conversion rate and diisobutylene selectivity in Table 7 are the isobutylene single-pass conversion rate and diisobutylene selectivity in the isobutylene stacking reactor (72).

[0130] It can be seen from Table 7 that when the distillate amount of the first reaction separation tower (62) (equivalent to the flow rate of the fifth logistics (5)) increases: ① the mass fraction of water in the fifth logistics increases, ② the single-pass conversion rate of isobutylene decreases, ③ but due to the increase in the mass fraction of polar component water, it is conducive to the production of pseudo trimers and tetramers, resulting in an increase in the selectivity of diisobutylene, and ④ the energy consumption of the device increases.

[0131] Embodiment 7 to Embodiment 12

[0132] In Examples 7 to 12, the diisobutylene split ratio was changed respectively, and the other parameters were the same as those in Example 1.

[0133] Table 8 Changes of relevant parameters when changing the diisobutylene split ratio

[0134]

[0135] Note: The diisobutylene yield in Table 8 refers to the ratio of the mass flow rate of diisobutylene in the diisobutylene product logistics (the 20th logistics) to the mass flow rate of diisobutylene when all the tert-butanol in the tert-butanol raw material (the first logistics) is converted into diisobutylene, and the mixed wastewater refers to the water obtained by mixing the first wastewater with the second wastewater.

[0136] It can be seen from Table 8 that with the increase of the diisobutylene split ratio, the diisobutylene yield increases and the organic impurity content in the wastewater decreases, but the size of the relevant equipment increases and the energy consumption of the device increases; when the diisobutylene split ratio increases to 70, the diisobutylene yield increases significantly, and when the diisobutylene split ratio increases to 110, the energy consumption of the device increases significantly.

[0137] Example 13 to Example 18

[0138] The water split ratios were changed in Examples 13 to 18 respectively, and the other parameters were the same as those in Example 1.

[0139] Table 9 Changes of relevant parameters when changing the water split ratio

[0140]

[0141] Note: The diisobutylene yield in Table 9 refers to the ratio of the mass flow rate of diisobutylene in the diisobutylene product logistics (the 20th logistics) to the mass flow rate of diisobutylene when all the tert-butanol in the tert-butanol raw material (the first logistics) is converted into diisobutylene, and the mixed wastewater refers to the water obtained by mixing the first wastewater with the second wastewater.

[0142] It can be seen from Table 9 that as the water split ratio increases, the yield of diisobutylene increases and the content of organic impurities in the wastewater decreases, but the size of related equipment increases and the energy consumption of the device increases; when the water split ratio increases to 1.75, the yield of diisobutylene increases significantly, and when the water split ratio increases to 3.50, the energy consumption of the device increases significantly.

[0143] Embodiment 19

[0144] The raw materials and operating conditions are exactly the same as those in Example 1. In the fifteenth logistics (15) of Example 1, a material with a mass flow rate of 500.00 kg / h is separated. The mass fraction of isobutylene in the material is greater than 99.75%, which can be used as the isobutylene product through the fifteenth A logistics (15A) output device and used for sale.

[0145] Embodiment 20

[0146] The other operating conditions are exactly the same as those in Example 1, except that the reflux ratio of the second reaction separation tower (65) is changed. The reflux ratio of the second reaction separation tower (65) in Example 1 is increased from 2.5 to 5.0. Then, the mass fraction of water in the second wastewater is increased from 99.6842% in Example 1 to 99.9617%. After being mixed with the first wastewater (the twenty-third logistics) discharged from the bottom of the water separation tower (64), the mass fraction of water in the generated mixed wastewater is 99.9830%, which can be used for water injection into the high-pressure air cooler of the hydrocracking unit.

[0147] Comparative Example 1

[0148] Comparative Example 1 (Publication No. US4423271A) adopts tert-butyl alcohol hydrolysis method to prepare high-purity isobutylene. The raw material flow rate, composition and boundary conditions adopted are the same as those in Example 1, and the product specifications and product yields are the same as those in Example 1. Comparative Example 1 First, the tert-butyl alcohol raw material 1 enters the tert-butyl alcohol hydrolysis reactor R, and the reaction product enters the K1 tower, isobutylene is separated at the top of the K1 tower, and the tert-butyl alcohol-water mixture is separated at the bottom of the K1 tower. A part of the tert-butyl alcohol-water mixture returns to the tert-butyl alcohol hydrolysis reactor R, and the other part enters the K2′ tower. After the impurities such as diisobutylene are separated at the top of the K2′ tower, the mixture at the bottom of the K2′ tower enters the K2 tower, and the tert-butyl alcohol-water azeotrope and waste water are separated at the top and bottom of the K2 tower, respectively, and the separated tert-butyl alcohol-water azeotrope is all returned to the tert-butyl alcohol hydrolysis reactor R. The total flow rate of the tert-butanol-water mixture and the tert-butanol-water azeotrope circulated to the tert-butanol hydrolysis reactor R is 6.5 to 16.0 times the flow rate of the tert-butanol raw material 1, and the energy consumption of the device is 216 kgoe / t diisobutylene product, which is much higher than the energy consumption of the device in Example 1 of 167 kgoe / t diisobutylene product.

[0149] Comparative Example 2

[0150] Comparative Example 2 (Publication No. CN106336601A) uses tert-butyl alcohol produced as a byproduct of propylene oxide to produce high-purity isobutylene. The COD content of stream a (wastewater) produced during the hydrolysis of tert-butyl alcohol is 9.34×10 4 mg / L, and the mass fraction of alcohol in logistics a is 1.95%, ether is 0.92%, ester is 1.13%, aldehyde and ketone is 0.08%, and olefin is 0.27%. Due to the high impurity content in the wastewater of logistics a, it cannot be directly transported to the sewage treatment plant for treatment. Logistics a is sent to a fixed bed reactor for hydrogenation treatment at a pressure of 3.0 MPa and a space velocity of 35 h -1 , and temperature of 200°C, a logistics b is obtained, in which the mass fraction of alcohol compounds is 4.09%, ether compounds <20 mg / L, olefins <15 mg / L, and alkanes is 0.27%. Logistics b is flash-distilled at 0.1 MPa, and a mixed stream c of C3, C4 and a small amount of water with a boiling point of 75-85°C is produced from the top of the tower, and a logistics d with a boiling point of 102°C is produced from the bottom of the tower. Logistics d is condensed to separate logistics e rich in macromolecular alcohols and alkanes, and a wastewater logistics f with a COD content of 327 mg / L.

[0151] Compared with Comparative Example 2, the mass fraction of water in the mixed wastewater produced in Example 3 is 99.9830%, which can be used for water injection into the high-pressure air cooler of the hydrocracking unit, and can also be directly transported to the sewage treatment plant without treatment measures such as hydrogenation and condensation, thereby simplifying the process.

Claims

1. A device for producing diisobutylene using tert-butyl alcohol as raw material, characterized in that: The device comprises a tert-butyl alcohol hydrolysis reactor (71), a first reaction separation tower (62) and an isobutylene stacking reactor (72); The tert-butyl alcohol raw material undergoes a hydrolysis reaction in a tert-butyl alcohol hydrolysis reactor (71) under the action of a tert-butyl alcohol hydrolysis catalyst to generate isobutylene and water; The first reaction separation tower (62) comprises an upper first rectifying section (621) and a lower first stripping section (622), a first reaction section (6211) is further provided in the first rectifying section (621), a reaction product feed position of the tert-butyl alcohol hydrolysis reactor (71) is located between the first rectifying section (621) and the first stripping section (622), a lead-out port is provided at the lower side of the first stripping section (622) for extracting diisobutylene and a portion of water in the first reaction separation tower (62), and a lead-out port is provided at the bottom of the first stripping section (622) for extracting unreacted tert-butyl alcohol and another portion of water; The unreacted isobutylene and some low-boiling azeotropes in the first reaction separation tower (62) undergo an isobutylene superposition reaction in the isobutylene superposition reactor (72).

2. The device according to claim 1, characterized in that: The device further comprises: a pretreatment tower (61) for separating light components or azeotropes with a lower boiling point from the tert-butyl alcohol raw material.

3. The device according to claim 1, characterized in that: The device further comprises: a second reaction and separation tower (65) for further reaction and separation of the bottom material of the first reaction and separation tower (62).

4. The device according to claim 3, characterized in that: The second reaction separation tower (65) comprises an upper second rectifying section (651) and a lower second stripping section (652); the feed position of the bottom material of the first reaction separation tower (62) is located between the second rectifying section (651) and the lower second stripping section (652); a second reaction section (6511) is further provided in the second rectifying section (651); and a third reaction section (6521) is further provided in the second stripping section (652); the second reaction section (6511) and the third reaction section (6521) are used to hydrolyze tert-butanol in the bottom material of the first reaction separation tower (62) to generate isobutylene and water.

5. The device according to claim 1, characterized in that: The device further comprises: a first decanter (91) for separating the material discharged from the lower side of the first stripping section (622) to form a first oil phase and a first water phase, wherein the first oil phase comprises diisobutylene and the first water phase comprises water.

6. The device according to claim 5, characterized in that: The device further comprises: a diisobutylene separation tower (63) for further separating and purifying the diisobutylene in the first oil phase separated by the first decanter (91).

7. The device according to claim 5, characterized in that: The device further comprises: a water separation tower (64) for further separating and purifying the water in the first water phase separated by the first decanter (91).

8. The device according to claim 4, characterized in that: The device further comprises: a second decanter (92) for separating the top distillate of the second reaction separation tower (65) to form a second oil phase and a second water phase, wherein the second oil phase contains isobutylene and the second water phase contains water; The second aqueous phase is output to the first decanter (91) for further separation and purification of water in the second aqueous phase.

9. The device according to claim 8, characterized in that The device further comprises: an isobutylene separation tower (66) for further separating and purifying the isobutylene in the second oil phase separated by the second decanter (92).

10. A method for producing diisobutylene using tert-butyl alcohol as a raw material, characterized in that: A device for producing diisobutylene using tert-butyl alcohol as a raw material according to any one of claims 1 to 9.

11. The method according to claim 10, characterized in that include: The hydrolysis reaction product of tert-butyl alcohol in the tert-butyl alcohol hydrolysis reactor (71) is in the first reaction separation tower (62), and isobutylene and low-boiling azeotropes flow toward the upper part of the tower. When flowing to the catalyst bed of the first reaction section (6211), under the action of the isobutylene superposition catalyst, a reaction of selective superposition of isobutylene to generate diisobutylene occurs, and the generated diisobutylene and some high-boiling azeotropes flow toward the lower part of the tower; the unreacted isobutylene and some low-boiling azeotropes in the tower continue to flow upward and are distilled off at the top of the tower, and are transported to the isobutylene superposition reactor (72) through the fifth stream (5) for isobutylene superposition reaction; The seventh stream (7) is drawn out from the side line of the first reaction separation tower (62), and the diisobutylene generated by the reaction in the first reaction separation tower (62) and the isobutylene superposition reactor (72), and the water partially generated by the reaction in the tert-butyl alcohol hydrolysis reactor (71) are transported to the first decanter (91) to separate the diisobutylene for further separation and purification.

12. The method according to claim 11, characterized in that The mass flow rate ratio of the seventh stream (7) extracted from the first reaction separation tower (62) to the fourth stream (4) used as feed to the first reaction separation tower (62) is controlled to be between 0.6 and 0.

9.

13. The method of claim 11, characterized in that Also includes: The ninth stream (9) is extracted from the bottom of the first reaction and separation tower (62) and transported to the second reaction and separation tower (65) for further reaction and separation.

14. The method of claim 13, characterized in that The diisobutylene split ratio is the ratio of the mass flow rate of diisobutylene in the seventh logistics (7) to the mass flow rate of diisobutylene in the ninth logistics (9), and the diisobutylene split ratio is controlled in the range of 30-130, preferably 50-110, and particularly preferably 70-90; the water split ratio is the ratio of the mass flow rate of water in the seventh logistics (7) to the mass flow rate of water in the ninth logistics (9), and the water split ratio is controlled in the range of 1.25-4.50, preferably 1.50-3.50, and particularly preferably 1.75-2.50.

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