Method for producing tert-amyl ethyl ether through heterogeneous auxiliary reaction extraction and pressure swing distillation

Abstract

The invention relates to a method for producing tert-amyl ethyl ether through heterogeneous auxiliary reaction extraction and pressure swing distillation. A reactive distillation tower T1, a first extractive distillation tower T2, a second extractive distillation tower T3 and an extraction agent recovery tower T4 are connected in series for operation, ionic liquid is used as an extraction agent, azeotropy between systems is broken under the action of the extraction agent, and reaction and separation of a tert-amyl alcohol-ethanol-ethyl tert-amyl ether-water multi-element azeotropic system are achieved. According to the method disclosed by the invention, on the premise of breaking the complex azeotropic behavior between systems, the energy consumption is further reduced, the purity of the product ethyl tert-amyl ether is improved, and the equipment cost is reduced. The purity of separated tert-amyl alcohol is greater than 99.9%, ethanol is completely reacted, the purity of water is greater than 99.9%, the purity of ethyl tert-amyl ether is greater than 99.9%, and the purity of extraction is greater than 99.9%. The adopted extracting agent ionic liquid is less in dosage, relatively weak in volatility, less in loss, easy to recover and environment-friendly.

Description

TECHNICAL FIELD

[0001] The present application belongs to the field of chemical separation and purification, and particularly relates to a heterogeneous assisted reaction extraction pressure swing distillation process for separating tertiary amyl alcohol, ethanol, water and ethyl tertiary amyl ether in esterification reaction by using imidazole acetate ionic liquid as an extractant. BACKGROUND

[0002] Ethyl tertiary amyl ether, as a gasoline additive with excellent performance and high-value solvent, can effectively improve the octane number of gasoline, improve the combustion performance and reduce the exhaust emission. As a chemical intermediate, it also has application potential in the fields of organic synthesis, perfumes and medicines. However, in the synthesis process of ethyl tertiary amyl ether (usually involving etherification reaction of tertiary amyl alcohol and ethanol), the reaction system also faces the challenge of complex azeotropic separation. Due to the formation of various azeotropes among alcohol, ether and water, it is difficult to achieve efficient separation and purification of the product by using conventional distillation technology.

[0003] In the process of synthesizing ethyl tertiary amyl ether by direct etherification of tertiary amyl alcohol and ethanol, various complex azeotropic mixtures are formed by homogeneous or heterogeneous catalytic reaction. Five binary azeotropes are formed in the etherification reaction system of tertiary amyl alcohol and ethanol. The azeotropic point of the binary azeotrope of tertiary amyl alcohol-ethyl tertiary amyl ether is 95.83℃ at 1atm, the azeotropic point of the binary azeotrope of tertiary amyl alcohol-water is 86.4℃, the azeotropic point of the binary azeotrope of ethanol-ethyl tertiary amyl ether is 76.4℃, the azeotropic point of the binary azeotrope of ethanol-water is 78.04℃, and the azeotropic point of the binary azeotrope of ethyl tertiary amyl ether-water is 78.20℃. Since the conventional separation method cannot effectively separate the multiple azeotropes, the production of high-purity ethyl tertiary amyl ether and wastewater treatment become a challenge. The present application adopts the method of heterogeneous assisted reaction extraction pressure swing distillation to produce ethyl tertiary amyl ether, which couples reaction distillation and extraction pressure swing distillation on the basis of phase separator assistance, with the goal of reducing energy consumption and cost of the process. The optimal process is obtained by optimizing the operating parameters, and a green and sustainable ethyl tertiary amyl ether production process is realized.

[0004] Patent (CN103787841A) discloses a method for synthesizing ethyl tertiary amyl ether (TAEE), which uses 2-methylbutene and ethanol as raw materials, and aluminum-based composite metal oxide loaded with cesium acid salt of phosphotungstic acid as catalyst. The reaction temperature is 100℃-180℃, the reaction pressure is 2.0MPa-6.0MPa, the liquid hourly space velocity of 2-methylbutene is 1.0h-1-5.0h-1, and the molar ratio of ethanol to 2-methylbutene is 1.0:1-8.0:1. This method can continuously synthesize ethyl tertiary amyl ether by using fixed bed process. However, there is a large amount of energy consumption in the reaction process, which increases the cost and load of the running equipment.

[0005] The application produces ethyl tert-amyl ether by adopting a heterogeneous auxiliary reaction extraction pressure swing rectification method, uses 1-butyl-3-methyl imidazole acetate as an extractant, uses the characteristics that the addition of the extractant affects the relative volatility of the azeotropic system, breaks the azeotropy among ethanol-ethyl tert-amyl ether-tert-amyl alcohol-water, and realizes the efficient and energy-saving separation of the ethyl tert-amyl ether and water azeotrope by coupling a phase separator and a pressure swing rectification device. The method can make the purity of the tert-amyl alcohol, ethanol, ethyl tert-amyl ether, 1-butyl-3-methyl imidazole acetate and water all reach more than 99.9%, and the high-purity extractant can be recycled and reused, finally forming a heterogeneous auxiliary reaction extraction pressure swing rectification method for producing ethyl tert-amyl ether, effectively reducing the energy consumption, improving the purity of the tert-amyl alcohol, ethanol, ethyl tert-amyl ether, 1-butyl-3-methyl imidazole acetate and water, and reducing the equipment cost. SUMMARY

[0006] The application aims to provide a heterogeneous auxiliary reaction extraction pressure swing rectification method for producing ethyl tert-amyl ether and related devices. The coupling influence mechanism of the ionic liquid as an extractant on the separation of the tert-amyl alcohol-ethyl tert-amyl ether-ethanol-water azeotropic system is used, and the separation characteristics of the phase separator are combined to obtain high-purity products while realizing a significant reduction in process energy consumption.

[0007] The application overcomes the shortcomings of the prior art, and proposes a heterogeneous auxiliary reaction extraction pressure swing rectification method for producing ethyl tert-amyl ether, which uses the extractant to affect the relative volatility between azeotropic systems, changes the equilibrium composition, and changes the characteristics that the pressure swing rectification azeotropic composition changes significantly with pressure. 1-butyl-3-methyl imidazole acetate is used as an extractant, and an ionic liquid is used as an extractant to assist the reaction extraction pressure swing rectification process, to realize the efficient separation of the five components of tert-amyl alcohol, ethanol, ethyl tert-amyl ether, 1-butyl-3-methyl imidazole acetate and water. The proposed method solves the problems of complex process, large amount of extractant, high energy consumption and high equipment cost in the current technology, and improves the purity of the product.

[0008] To achieve the above-mentioned purposes, the technical scheme of the utility model is: reactive distillation column T1, first extractive distillation column T2, second extractive distillation column T3, extractant recovery column T4, condenser C1, condenser C2, condenser C3, condenser C4, reboiler R1, reboiler R2, reboiler R3, reboiler R4, heat exchanger H1, centrifugal pump P1, centrifugal pump P2, centrifugal pump P3, centrifugal pump P4; feed stream F1, feed stream F2 are connected to the middle of the reactive distillation column T1, the gaseous phase outlet of the top of the reactive distillation column T1 is connected to the condenser C1 and then divided into two branches, one is connected to the first extractive distillation column T2 through the centrifugal pump P1, and the other is connected to the top of the reactive distillation column T1, the liquid phase outlet of the bottom of the reactive distillation column T1 extracts high-purity tertiary amyl alcohol; the extractant feed stream S1 is connected to the upper middle of the first extractive distillation column T2, the liquid phase outlet of the bottom of the first extractive distillation column T2 is connected to the reboiler R2 and then divided into two branches, one is connected to the second extractive distillation column T3 through the centrifugal pump P2, and the other is connected to the top of the first extractive distillation column T2, the gaseous phase outlet of the top of the first extractive distillation column T2 extracts high-purity ethyl tertiary amyl ether; the extractant feed stream S2 is connected to the top of the second extractive distillation column T3, the liquid phase outlet of the bottom of the second extractive distillation column T3 is connected to the reboiler R3 and then divided into two branches, one is connected to the extractant recovery column T4 through the centrifugal pump P3, and the other is connected to the top of the second extractive distillation column T3, the gaseous phase outlet of the top of the second extractive distillation column T3 extracts high-purity tertiary amyl alcohol; the liquid phase outlet of the bottom of the extractant recovery column T4 is connected to the reboiler R4 and then divided into two branches, one is connected to the first extractive distillation column T2 and the second extractive distillation column T3 through the centrifugal pump P4, respectively, and the extractant is introduced into the first extractive distillation column T2 and the second extractive distillation column T3 through the feed stream S1 and the feed stream S2 for recycling, and the other is connected to the top of the extractant recovery column T4, and the gaseous phase outlet of the top of the extractant recovery column T4 extracts high-purity water; The method for producing ethyl tertiary amyl ether by heterogeneous auxiliary reaction extractive pressure swing distillation using the above device includes the following steps: (1) The reactant feed stream F1 of ethanol and the feed stream F2 of tertiary amyl alcohol enter the reactive distillation column T1, react and separate after effective contact, part of the liquid phase at the bottom of the reactive distillation column T1 enters the reboiler R1 to be heated and vaporized and then returns to the bottom of the reactive distillation column T1, and part of the liquid phase at the bottom of the reactive distillation column T1 extracts high-purity tertiary amyl alcohol, the gaseous phase at the top of the reactive distillation column T1 is condensed by the condenser C1, part of which returns to the top of the reactive distillation column T1, and the other part extracts the tertiary amyl alcohol-ethanol-ethyl tertiary amyl ether-water azeotrope and is sent to the first extractive distillation column T2 through the centrifugal pump P1; (2) After the extractant feed stream S1 1-butyl-3-methylimidazolium acetate and the tertiary amyl alcohol-ethanol-ethyl tertiary amyl ether-water azeotrope mixture from the reaction distillation column T1 column bottom enter the first extractive distillation column T2, the first extractive distillation column T2 overhead vapor phase is condensed by the condenser C2, part of which returns to the first extractive distillation column T2 overhead, and part of which is extracted as high-purity ethyl tertiary amyl ether, and the first extractive distillation column T2 column bottom liquid phase part enters the reboiler R2 to be heated and vaporized and then returns to the first extractive distillation column T2 column bottom, and the other part of the tertiary amyl alcohol-ethanol-water-extractant 1-butyl-3-methylimidazolium acetate mixture is sent to the second extractive distillation column T3 by the centrifugal pump P2; (3) After the tertiary amyl alcohol-ethanol-water-extractant mixture enters the second extractive distillation column T3, the second extractive distillation column T3 overhead vapor phase is condensed by the condenser C3, part of which returns to the second extractive distillation column T3 overhead, and part of which is extracted as high-purity tertiary amyl alcohol, and the second extractive distillation column T3 column bottom liquid phase part enters the reboiler R3 to be heated and vaporized and then returns to the second extractive distillation column T3 column bottom, and the other part of the water-extractant 1-butyl-3-methylimidazolium acetate mixture is sent to the extractant recovery column T4 by the centrifugal pump P3; (4) After the extractant-water azeotrope mixture enters the extractant recovery column T4, the extractant recovery column T4 overhead vapor phase is condensed by the condenser C4, part of which returns to the extractant recovery column T4 overhead, and part of which is extracted as high-purity water, and the extractant recovery column T4 column bottom liquid phase part enters the reboiler R4 to be heated and vaporized and then returns to the extractant recovery column T4 column bottom, and the other part of the high-purity extractant is sent to the second extractive distillation column T3 and the first extractive distillation column T2 for recycling by the centrifugal pump P4 through the heat exchanger H1; The feed flow rate of the reactant feed stream F1 ethanol and the feed stream F2 tertiary amyl alcohol of the reaction distillation column T1 is 4427-4828 kg / h, the feed temperature is 25°C, the operating pressure is 1-1.3 atm, the number of plates is 30-40, the feed positions of the reactants ethanol and tertiary amyl alcohol are the 26th-36th plate and the 6th-16th plate, respectively, the column top temperature is 35-40°C, the column bottom temperature is 70-75°C, and the number of plates in the reaction section is the 4th-26th plate; The operating pressure of the first extractive distillation column T2 is 0.2 atm (gauge pressure), the number of plates is 38, the feed position of the mixture is the 21st plate, the feed position of the introduced extractant is the 4th plate, the column top temperature is 54.39°C, and the column bottom temperature is 89.81°C; The operating pressure of the second extractive distillation column T3 is 0.45 atm, the number of plates is 40, the feed position of the mixture is the 32nd plate, the feed position of the introduced extractant is the 4th plate, the column top temperature is 81.39°C, and the column bottom temperature is 186.76°C; The extraction agent recovery column T4 operates at a pressure of 0.25 atm (gauge), has 40 plates, the feed is at plate 4, the overhead temperature is 62.9°C, and the bottom temperature is 320.05°C.

[0009] According to another preferred embodiment of the present application, the steam consumption for producing one ton of ethyl tert-amyl ether is 41 Kg / h.

[0010] According to another embodiment of the present application, the use of ionic liquid as extraction agent is that the first extraction rectification column T2 and the second extraction rectification column T3 use ionic liquid extraction at plate 4, and the heat duty of the reboiler R1 and the reboiler R2 is 610.233 KW and 1135.29 KW, respectively.

[0011] According to another embodiment of the present application, the purity of the separated tert-amyl alcohol is greater than 99.9%, the ethanol has been completely reacted, the purity of the water is greater than 99.8%, the purity of the ethyl tert-amyl ether is greater than 99.9%, and the purity of the extraction agent 1-butyl-3-methylimidazolium acetate is greater than 99.9%.

[0012] The method for producing tert-amyl methyl ether by heterogeneous auxiliary reaction extraction pressure swing distillation according to the present application is described in detail as follows: The feed stream F1 and the feed stream F2 are connected to the middle of the reaction rectification column T1, the gas phase outlet of the top of the reaction rectification column T1 is connected to the condenser C1 and then divided into two branches, one is connected to the first extraction rectification column T2 through the centrifugal pump P1, and the other is connected to the top of the reaction rectification column T1, and the liquid phase outlet of the bottom of the reaction rectification column T1 is used to extract high-purity tert-amyl alcohol; the extraction agent feed stream S1 is connected to the upper middle of the first extraction rectification column T2, the liquid phase outlet of the bottom of the first extraction rectification column T2 is connected to the reboiler R2 and then divided into two branches, one is connected to the second extraction rectification column T3 through the centrifugal pump P2, and the other is connected to the top of the first extraction rectification column T2, and the gas phase outlet of the top of the first extraction rectification column T2 is used to extract high-purity ethyl tert-amyl ether; the extraction agent feed stream S2 is connected to the top of the second extraction rectification column T3, the liquid phase outlet of the bottom of the second extraction rectification column T3 is connected to the reboiler R3 and then divided into two branches, one is connected to the extraction agent recovery column T4 through the centrifugal pump P3, and the other is connected to the top of the second extraction rectification column T3, and the gas phase outlet of the top of the second extraction rectification column T3 is used to extract high-purity tert-amyl alcohol; the liquid phase outlet of the bottom of the extraction agent recovery column T4 is connected to the reboiler R4 and then divided into two branches, one is connected to the first extraction rectification column T2 and the second extraction rectification column T3 through the centrifugal pump P4, respectively, and the extraction agent is introduced into the first extraction rectification column T2 and the second extraction rectification column T3 through the feed stream S1 and the feed stream S2 for recycling, and the other is connected to the top of the extraction agent recovery column T4, and the gas phase outlet of the top of the extraction agent recovery column T4 is used to extract high-purity water. The feed flow of the reactants of the reactive rectification column T1 is 4427-4828 kg / h, the feed temperature is 25℃, the operating pressure is 1-1.3 atm (gauge pressure), the number of plates is 30-40, the feed positions of the reactants ethanol and tertiary amyl alcohol are the 26th-36th plate and the 6th-16th plate respectively, the top temperature is 35-40℃, the bottom temperature is 70-75℃, and the number of plates in the reaction section is the 4th-26th plate; the operating pressure of the first extractive rectification column T2 is 0.2 atm (gauge pressure), the number of plates is 38, the feed position of the mixture is the 21st plate, the feed position of the introduced extractant is the 4th plate, the top temperature is 54.39℃, and the bottom temperature is 89.81℃; The operating pressure of the second extractive rectification column T3 is 0.45 atm (gauge pressure), the number of plates is 40, the feed position of the mixture is the 32nd plate, the feed position of the introduced extractant is the 4th plate, the top temperature is 81.39℃, and the bottom temperature is 186.76℃; the operating pressure of the extractant recovery column T4 is 0.25 atm (gauge pressure), the number of plates is 40, the feed position is the 4th plate, the top temperature is 62.9℃, and the bottom temperature is 320.05℃.

[0013] The purity of the tertiary amyl alcohol separated by the method is greater than 99.9%, the ethanol has been completely reacted, the purity of the water is greater than 99.8%, the purity of the ethyl tertiary amyl ether is greater than 99.9%, and the purity of the extractant is greater than 99.9%.

[0014] [Advantages]

[0015] Compared with the prior art, the present application has the following advantages: (1) The purities of the water, the tertiary amyl alcohol, the ethyl tertiary amyl ether and the extractant separated by the heterogeneous auxiliary reaction-extraction pressure swing rectification method are improved.

[0016] (2) After using the ionic liquid as the extractant, the second extractive rectification column T3 effectively separates most of the water in the system, and the remaining extractant-water azeotrope mixture enters the conventional rectification column for separation, which not only reduces the separation difficulty, but also greatly reduces the energy consumption.

[0017] (3) The amount of the extractant used is small, the equipment investment is small, the extractant used is easy to recover, has good chemical thermal stability, and is green and pollution-free. BRIEF DESCRIPTION OF DRAWINGS

[0018] In order to more clearly illustrate the technical solutions of the embodiments of the present application or the prior art, the drawings needed to be used in the description of the embodiments or the prior art will be briefly introduced as follows. Obviously, the drawings in the following description only constitute some embodiments of the present application, and for those skilled in the art, other drawings can also be obtained from these drawings without creative labor.

[0019] Figure 1 is a three-dimensional structure schematic diagram of the present application; The drawing is a schematic diagram of the method for producing ethyl tert-amyl ether by heterogeneous auxiliary reaction extraction pressure swing distillation. Figure 1 In the drawing, T1 is a reactive distillation column, T2 is an extractive distillation column, T3 is an extractive distillation column, T4 is a solvent recovery distillation column, C1 is a condenser, C2 is a condenser, C3 is a condenser, C4 is a condenser, R1 is a reboiler, R2 is a reboiler, R3 is a reboiler, R4 is a reboiler, H1 is a heat exchanger, P1 is a centrifugal pump, P2 is a centrifugal pump, P3 is a centrifugal pump, and P4 is a centrifugal pump. DETAILED DESCRIPTION

[0020] The present application will be further described below with reference to the drawings, but not limited to the scope of the present application.

[0021] Embodiment 1:

[0022] By using Figure 1The flow chart shows that the feed flow rate of the reactive distillation column T1 is 55 kmol / h, the feed temperature is 25℃, the feed composition is 18.18% (mole fraction) of ethanol and 81.82% (mole fraction) of tertiary amyl alcohol, the operating pressure is 1 atm, the number of plates is 30, the feed positions of the reactants ethanol and tertiary amyl alcohol are the 26th plate and the 6th plate respectively, the column top temperature is 35℃, the column bottom temperature is 70℃, the number of plates in the reaction section is the 4th-26th plate, the reactive distillation column T1 distills out a tertiary amyl alcohol-ethanol-ethyl tertiary amyl ether-water azeotrope mixture from the column top and distills out pure tertiary amyl alcohol with a purity of 0.9995 from the column bottom; after the extractant 1-butyl-3-methylimidazolium acetate and the tertiary amyl alcohol-ethanol-ethyl tertiary amyl ether-water azeotrope mixture from the column bottom of the reactive distillation column T1 enter the first extractive distillation column T2, the gas phase at the column top of the first extractive distillation column T2 is condensed by a condenser C2 and then part of it is refluxed to the column top of the first extractive distillation column T2 and part of it is distilled out as ethyl tertiary amyl ether with a purity of 0.9992, the liquid phase at the column bottom of the first extractive distillation column T2 is partly heated and vaporized by a reboiler R2 and then refluxed to the column bottom of the first extractive distillation column T2 and the other part of it is distilled out as a tertiary amyl alcohol-ethanol-water-extractant 1-butyl-3-methylimidazolium acetate mixture which is sent into the second extractive distillation column T3 by a centrifugal pump P2; after the tertiary amyl alcohol-ethanol-water-extractant 1-butyl-3-methylimidazolium acetate mixture enters the second extractive distillation column T3, 22 kmol / h of the ionic liquid extractant 1-butyl-3-methylimidazolium acetate is introduced into the 4th plate, the gas phase at the column top of the second extractive distillation column T3 is condensed by a condenser C3 and then part of it is refluxed to the column top of the second extractive distillation column T3 and part of it is distilled out as tertiary amyl alcohol with a purity of 0.9993, the liquid phase at the column bottom of the second extractive distillation column T3 is partly heated and vaporized by a reboiler R3 and then refluxed to the column bottom of the second extractive distillation column T3 and the other part of it is distilled out as a water-extractant 1-butyl-3-methylimidazolium acetate mixture which is sent into the solvent recovery second extractive distillation column T3 by a centrifugal pump P3; after the 1-butyl-3-methylimidazolium acetate-water azeotrope mixture enters the extractant recovery column T4, the gas phase at the column top of the extractant recovery column T4 is condensed by a condenser C4 and then part of it is refluxed to the column top of the extractant recovery column T4 and part of it is distilled out as water with a purity of 0.9991, the liquid phase at the column bottom of the extractant recovery column T4 is partly heated and vaporized by a reboiler R4 and then refluxed to the column bottom of the extractant recovery column T4 and the other part of it is distilled out as the extractant with a purity of 0.9999 which is circulated back to the second extractive distillation column T3 and the first extractive distillation column T2 respectively by a centrifugal pump P4 through a heat exchanger H1.

[0023] Example 2:

[0024] By using Figure 1The flow chart shows that the feed flow rate of the reactive distillation column T1 is 57 kmol / h, the feed temperature is 25℃, the feed composition is 18.18% (mole fraction) of ethanol and 81.82% (mole fraction) of tertiary amyl alcohol, the operating pressure is 1.3 atm (gauge pressure), the number of plates is 35, the feed positions of the reactants ethanol and tertiary amyl alcohol are the 31st plate and the 11th plate, respectively, the column top temperature is 38℃, the column bottom temperature is 73℃, the number of plates in the reaction section is the 4th to the 26th plate, the reactive distillation column T1 distills off a tertiary amyl alcohol-ethanol-ethyl tertiary amyl ether-water azeotrope mixture from the column top and distills off pure tertiary amyl alcohol with a purity of 0.9995 from the column bottom; after the extractant 1-butyl-3-methylimidazolium acetate and the tertiary amyl alcohol-ethanol-ethyl tertiary amyl ether-water azeotrope mixture from the column bottom of the reactive distillation column T1 enter the first extractive distillation column T2, the gas phase at the column top of the first extractive distillation column T2 is condensed by a condenser C2 and then part of it is refluxed to the column top of the first extractive distillation column T2 and part of it is distilled off as ethyl tertiary amyl ether with a purity of 0.9992, the liquid phase at the column bottom of the first extractive distillation column T2 is partly heated and vaporized by a reboiler R2 and then refluxed to the column bottom of the first extractive distillation column T2 and the other part of it is distilled off as a tertiary amyl alcohol-ethanol-water-extractant 1-butyl-3-methylimidazolium acetate mixture which is sent into the second extractive distillation column T3 by a centrifugal pump P2; after the tertiary amyl alcohol-ethanol-water-extractant 1-butyl-3-methylimidazolium acetate mixture enters the second extractive distillation column T3, the gas phase at the column top of the second extractive distillation column T3 is condensed by a condenser C3 and then part of it is refluxed to the column top of the second extractive distillation column T3 and part of it is distilled off as tertiary amyl alcohol with a purity of 0.999, the liquid phase at the column bottom of the second extractive distillation column T3 is partly heated and vaporized by a reboiler R3 and then refluxed to the column bottom of the second extractive distillation column T3 and the other part of it is distilled off as a water-extractant 1-butyl-3-methylimidazolium acetate mixture which is sent into the solvent recovery second extractive distillation column T3 by a centrifugal pump P3; after the 1-butyl-3-methylimidazolium acetate-water azeotrope mixture enters the extractant recovery column T4, the gas phase at the column top of the extractant recovery column T4 is condensed by a condenser C4 and then part of it is refluxed to the column top of the extractant recovery column T4 and part of it is distilled off as water with a purity of 0.999, the liquid phase at the column bottom of the extractant recovery column T4 is partly heated and vaporized by a reboiler R4 and then refluxed to the column bottom of the extractant recovery column T4 and the other part of it is distilled off as extractant with a purity of 0.9999 which is circulated back to the second extractive distillation column T3 and the first extractive distillation column T2 by a centrifugal pump P4 through a heat exchanger H1, respectively.

[0025] Example 3:

[0026] By using Figure 1The flowchart shown illustrates that the feed flow rate of reactive distillation column T1 is 60 kmol / h, the feed temperature is 25℃, and the feed composition is 18.18% (mole fraction) ethanol and 81.82% (mole fraction) tert-amyl alcohol. The operating pressure is 1.2 atm (gauge pressure), and the column has 40 trays. The feed positions for the reactants ethanol and tert-amyl alcohol are tray 36 and 16, respectively. The top temperature is 40℃, the bottom temperature is 75℃, and the reaction section comprises trays 4-26. The top product of reactive distillation column T1 is an azeotropic mixture of tert-amyl alcohol, ethanol, ethyl tert-amyl ether, and water. The bottom product of reactive distillation column T1 has a purity of [missing information]. The extractant 1-butyl-3-methylimidazolium acetate and the azeotropic mixture of tert-amyl alcohol, ethanol, ethyl tert-amyl ether, and water from the bottom of reactive distillation column T1 enter the first extractive distillation column T2. ​​The vapor phase from the top of column T2 is condensed in condenser C2, with a portion refluxed back to the top of column T2 and a portion collected as ethyl tert-amyl ether with a purity of 0.9993. The liquid phase from the bottom of column T2 is partially heated and vaporized in reboiler R2 and then refluxed back to the bottom of column T2. ​​The remaining portion is a mixture of tert-amyl alcohol, ethanol, water, and 1-butyl-3-methylimidazolium acetate from the bottom of reactive distillation column T1. The 3-methylimidazolium acetate mixture is fed into the second extractive distillation column T3 by centrifugal pump P2. After the tert-amyl alcohol-ethanol-water-extractant 1-butyl-3-methylimidazolium acetate mixture enters the second extractive distillation column T3, the vapor phase at the top of column T3 is condensed by condenser C3, with a portion refluxed back to the top of column T3 and a portion collected as 0.9994% tert-amyl alcohol. The liquid phase at the bottom of column T3 is partially heated and vaporized in reboiler R3 and then refluxed back to the bottom of column T3; the remaining portion, the water-extractant 1-butyl-3-methylimidazolium acetate mixture, is then pumped into the second extractive distillation column T3 by centrifugal pump P2. Centrifugal pump P3 feeds the solvent recovery into the second extractive distillation column T3; the azeotropic mixture of 1-butyl-3-methylimidazolium acetate and water enters the extractant recovery column T4. After the vapor phase at the top of the extractant recovery column T4 is condensed by condenser C4, part of it is returned to the top of the extractant recovery column T4, and part of it is water with a purity of 0.999%. Part of the liquid phase at the bottom of the extractant recovery column T4 enters the reboiler R4 for heating and vaporization, and then returns to the bottom of the extractant recovery column T4. The other part is extractant with a purity of 0.9999, which is recycled by centrifugal pump P4 through heat exchanger H1 to the second extractive distillation column T3 and the first extractive distillation column T2, respectively.

[0027] The present invention has been described above with reference to the preferred embodiments shown in the accompanying drawings. However, it will be readily understood by those skilled in the art that the scope of protection of the present invention is obviously not limited to these specific embodiments. Without departing from the principle of the present invention, those skilled in the art can make equivalent changes or substitutions to the relevant technical features, and the technical solutions after such changes or substitutions will all fall within the scope of protection of the present invention.

Claims

1. A method for producing ethyl tert-amyl ether by heterogeneous assisted reaction extraction pressure swing distillation, wherein the apparatus for implementing this method mainly includes the following parts: The distillation column consists of reactive distillation column T1, first extractive distillation column T2, second extractive distillation column T3, extractant recovery column T4, condenser C1, condenser C2, condenser C3, condenser C4, reboiler R1, reboiler R2, reboiler R3, reboiler R4, heat exchanger H1, centrifugal pumps P1, P2, P3, and P4; feed streams F1 and F2 are connected to the middle of reactive distillation column T1, and the vapor phase exiting from the top of reactive distillation column T1... After being connected to condenser C1, the feed stream splits into two branches. One branch connects to the first extractive distillation column T2 via centrifugal pump P1, and the other branch connects to the top of reactive distillation column T1. High-purity tert-amyl alcohol is collected from the liquid phase outlet of the bottom of reactive distillation column T1. The extractant feed stream S1 is connected to the upper part of the first extractive distillation column T2. ​​After the liquid phase outlet of the bottom of the first extractive distillation column T2 is connected to reboiler R2, it splits into two branches. One branch connects to the second extractive distillation column T3 via centrifugal pump P2, and the other branch connects to the top of reactive distillation column T1. The feed stream S2 is connected to the top of the first extractive distillation column T2, where high-purity ethyl tert-amyl ether is collected from the vapor phase outlet. The extractant feed stream S2 is connected to the top of the second extractive distillation column T3. The liquid phase outlet of the bottom of the second extractive distillation column T3 is connected to the reboiler R3 and then splits into two branches: one branch connects to the extractant recovery column T4 via centrifugal pump P3, and the other branch connects to the top of the second extractive distillation column T3, where high-purity ethyl tert-amyl ether is collected from the vapor phase outlet. The extractant recovery tower T4 is connected to the reboiler R4 and then splits into two branches. One branch is connected to the first extractive distillation tower T2 and the second extractive distillation tower T3 via centrifugal pump P4. The extractant is fed into the first extractive distillation tower T2 and the second extractive distillation tower T3 through feed stream S1 and feed stream S2 respectively for recycling. The other branch is connected to the top of the extractant recovery tower T4. High-purity water is collected from the gas phase outlet of the top of the extractant recovery tower T4. The method for producing ethyl tert-amyl ether by heterogeneous assisted reaction extraction pressure swing distillation using the above-mentioned apparatus includes the following steps: (1) The reactant feed stream F1 ethanol and feed stream F2 tert-amyl alcohol enter the reactive distillation column T1. After effective contact, they react and separate. Part of the liquid phase at the bottom of the reactive distillation column T1 enters the reboiler R1 for heating and vaporization and is returned to the bottom of the reactive distillation column T1. Part of the liquid phase is collected as high-purity tert-amyl alcohol. The vapor phase at the top of the reactive distillation column T1 is condensed by the condenser C1. Part of the vapor phase is returned to the top of the reactive distillation column T1. The other part is collected as a tert-amyl alcohol-ethanol-ethyl tert-amyl ether-water azeotropic mixture and sent to the first extractive distillation column T2 by centrifugal pump P1. (2) The extractant feed stream S1 1-butyl-3-methylimidazolium acetate and the tert-amyl alcohol-ethanol-ethyl tert-amyl ether-water azeotropic mixture from the bottom of the reactive distillation column T1 enter the first extractive distillation column T2. ​​After the vapor phase at the top of the first extractive distillation column T2 is condensed by the condenser C2, part of it is returned to the top of the first extractive distillation column T2, and part of it is high-purity ethyl tert-amyl ether. Part of the liquid phase at the bottom of the first extractive distillation column T2 enters the reboiler R2 for heating and vaporization and then returns to the bottom of the first extractive distillation column T2. ​​The other part of the tert-amyl alcohol-ethanol-water-extractant 1-butyl-3-methylimidazolium acetate mixture is sent to the second extractive distillation column T3 by the centrifugal pump P2. (3) After the mixture of tert-amyl alcohol-ethanol-water-extractant enters the second extractive distillation column T3, part of the vapor phase at the top of the second extractive distillation column T3 is condensed by condenser C3 and returned to the top of the second extractive distillation column T3, and part of it is high-purity tert-amyl alcohol. Part of the liquid phase at the bottom of the second extractive distillation column T3 enters the reboiler R3 for heating and vaporization and is then refluxed to the bottom of the second extractive distillation column T3. The other part is the mixture of water-extractant 1-butyl-3-methylimidazolium acetate, which is sent to the extractant recovery column T4 by centrifugal pump P3. (4) After the extractant-water azeotropic mixture enters the extractant recovery tower T4, part of the vapor phase at the top of the extractant recovery tower T4 is condensed by the condenser C4 and returned to the top of the extractant recovery tower T4, and part of it is high-purity water. Part of the liquid phase at the bottom of the extractant recovery tower T4 enters the reboiler R4 for heating and vaporization and is returned to the bottom of the extractant recovery tower T4. The other part is high-purity extractant, which is sent by the centrifugal pump P4 through the heat exchanger H1 to the second extractive distillation tower T3 and the first extractive distillation tower T2 for recycling. The feed flow rates of reactant stream F1 (ethanol) and feed stream F2 (tert-amyl alcohol) in reactive distillation column T1 are 4427-4828 kg / h, the feed temperature is 25℃, the operating pressure is 1-1.3 atm (gauge pressure), the number of trays is 30-40, the feed positions of reactant ethanol and tert-amyl alcohol are trays 26-36 and 6-16 respectively, the top temperature is 35-40℃, the bottom temperature is 70-75℃, and the number of trays in the reaction section is 4-26. The first extractive distillation column T2 operates at a pressure of 0.2 atm (gauge pressure), has 38 trays, feeds the mixture onto the 21st tray, introduces the extractant onto the 4th tray, has a top temperature of 54.39℃, and a bottom temperature of 89.81℃. The second extractive distillation column T3 operates at a pressure of 0.45 atm (gauge pressure), has 40 trays, feeds the mixture onto the 32nd tray, introduces the extractant onto the 4th tray, has a top temperature of 81.39℃, and a bottom temperature of 186.76℃. The extractant recovery tower T4 operates at a pressure of 0.25 atm (gauge pressure), has 40 trays, feeds at the 4th tray, a top temperature of 62.9℃, and a bottom temperature of 320.05℃.

2. The method for producing ethyl tert-amyl ether by heterogeneous assisted reaction extraction pressure swing distillation according to claim 1, characterized in that: The extractants for both the first extractive distillation column T2 and the second extractive distillation column T3 are ionic liquids of imidazole acetate.

3. The method for producing ethyl tert-amyl ether by heterogeneous assisted reaction extraction pressure swing distillation according to claim 1, characterized in that: The feed position for the first extractive distillation column T2 and the second extractive distillation column T3, which use ionic liquid extraction, is the fourth plate. The heat loads of their reboilers R1 and R2 are 610.233KW and 1135.29KW, respectively.

4. The method for producing ethyl tert-amyl ether by heterogeneous assisted reaction extraction pressure swing distillation according to claim 1, characterized in that: The purity of the separated tert-amyl alcohol is greater than 99.9%, the purity of water is greater than 99.8%, the purity of ethyl tert-amyl ether is greater than 99.9%, and the purity of the extractant is greater than 99.9%.

5. The method for producing ethyl tert-amyl ether by heterogeneous assisted reactive extraction pressure swing distillation according to claim 1, characterized in that... The steam consumption for producing one ton of ethyl tert-amyl by reactive extraction pressure swing distillation is 41 kg / h.

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