Energy coupling variable pressure refining of butylamine separation and purification system and process

Abstract

The application provides a separation and purification system and process for energy coupling variable pressure refining of butylamine, which comprises atmospheric azeotropic distillation of butylamine raw material containing water to separate a first distillate and a first still residue; pressure azeotropic distillation of the first distillate to separate a second distillate and a first target product; refluxing of the second distillate and atmospheric azeotropic distillation with the first still residue and butylamine raw material containing water to separate a third distillate and a third still residue, wherein the third still residue comprises n-butylamine, di-n-butylamine and tri-n-butylamine; distillation of the third still residue to separate a second target product, a third target product and a fourth target product; and the reaction conditions are selected from at least one of the following: a reflux ratio of 1.6-3.0 and a temperature of 43-63 DEG C for the atmospheric azeotropic distillation; and a reflux amount of 535 kg / h-2470 kg / h for the second distillate. The system and process of the application can greatly reduce equipment and operation costs on the basis of obtaining high-purity n-butylamine, di-n-butylamine and tri-n-butylamine products.

Description

TECHNICAL FIELD

[0001] The present application relates to the field of fine chemical processing technology, in particular to a separation and purification system and process for energy coupling variable pressure refining of butylamine. BACKGROUND

[0002] Rectification is a mature separation technology in petrochemical production process. However, the use of traditional rectification method has high energy consumption, and with the continuous improvement of energy utilization rate, it is of great significance to study the energy-saving technology of chemical process, especially involving rectification operation.

[0003] n-Butylamine, its molecular formula is C4H11N, CAS number: 109-73-9, molecular weight 73.137, boiling point at normal pressure is about 78℃, at room temperature and normal pressure is colorless transparent liquid, miscible with water and chloroform, ether and other organic solvents, mainly used in medicine, dyes, pesticides, emulsifiers, etc.

[0004] Di-n-butylamine, its molecular formula is C8H19N, CAS number is 111-92-2, molecular weight is 129.243, boiling point at normal pressure is about 159℃, at room temperature and normal pressure is colorless transparent liquid, mainly used as corrosion inhibitor, emulsifier, pesticide, etc.

[0005] Tri-n-butylamine, its molecular formula is C12H27N, CAS number: 102-82-9, molecular weight 185.349, boiling point at normal pressure is about 216.5℃, at room temperature and normal pressure is colorless transparent liquid, soluble in water and chloroform, ether and other organic solvents, is an important organic synthesis intermediate, also a good solvent, rubber accelerator, dye and pesticide.

[0006] In the current production process of n-butylamine, the obtained product contains azeotrope (n-butylamine and water, 76kpaA azeotropic composition (98.7%, 1.3%), azeotropic temperature 69℃) and different organic amine products. The ordinary rectification method has the disadvantages of large investment and high energy consumption, therefore, in industrial production, it is very important to find a separation technology with low investment and operating cost and low energy consumption while ensuring the purity of the product.

[0007] At present, the existing research such as the patent application file with publication number CN101648874A discloses a continuous separation method of sec-butylamine, which includes sec-butyl alcohol separation rectification tower, azeotropic tower, di-sec-butylamine separation tower and phase separator, the process is simple, but the energy consumption is high and the investment is large for industrial production.

[0008] The patent application file with publication number CN116178174A discloses a method for purifying hexanediamine with low energy consumption, comprising the following steps: 1) extracting hexanediamine and impurities from water in the aqueous reaction solution coming out of the hexanediamine reaction system with ionic liquid to obtain an extraction mixture; 2) allowing the extraction mixture obtained in step 1) to stand and separate into layers, discharging the water phase as waste water, and the organic phase being a mixture of ionic liquid, hexanediamine and impurities; 3) separating the organic phase obtained in step 2), obtaining crude hexanediamine at the top and ionic liquid at the bottom, which is recycled to step 1) for recycling of the extraction agent; and 4) allowing the crude hexanediamine obtained in step 3) to enter a dividing wall column to remove light / heavy component impurities, thereby obtaining hexanediamine product with a purity of greater than 99.9wt%. The method discloses that the first step of separation of the raw material is carried out in a normal pressure device (extraction device), the extract enters a pressurized device (separation device), the liquid at the bottom of the pressurized device is returned to the normal pressure device for recycling, the top is the crude product, and the crude product enters the dividing wall column, three components are separated from the top, middle and bottom of the dividing wall column, and the product is obtained. However, the method is suitable for the separation and purification of hexanediamine, and cannot be directly applied to the separation and purification of butylamine.

[0009] The patent with publication number CN108144319B discloses a device for producing n-butylamine using a dividing wall rectification column, which comprises a fixed bed reactor, a first heat pump, a first heat exchanger, a first dividing wall rectification column, a second heat exchanger, a second heat pump, a second dividing wall rectification column and a third heat exchanger. The first and second dividing wall rectification columns have the same structure, and each comprises a vertical dividing wall in the middle of the inner cavity of the rectification column, which divides the middle part of the inner cavity of the rectification column into a feed side and a non-feed side. The feed side and the non-feed side are both filled with packing. The inner cavity of the rectification column above the dividing wall is a rectification section, which is filled with rectification section packing. The inner cavity of the rectification column below the dividing wall is a stripping section, which is filled with stripping section packing. The device uses a dividing wall rectification column to achieve the purpose of reducing energy consumption, but it uses two dividing wall rectification columns and is not suitable for the separation and purification of aqueous raw materials.

[0010] Therefore, if a separation and purification process for butylamine can be provided, which uses energy-saving distillation technology to improve the production process of traditional products, it has great economic value and practical significance for energy saving and efficiency improvement. SUMMARY

[0011] In view of the above-mentioned shortcomings of the prior art, the present application provides a separation and purification system and process for refining butylamine by energy coupling variable pressure, to solve the problems in the prior art that the existing butylamine separation and purification process cannot reduce energy consumption and operating costs while ensuring product purity.

[0012] To achieve the above and related purposes, the present application adopts the following technical solutions:

[0013] The first aspect of the present application provides a separation and purification process for energy-coupled transformation of butylamine, comprising the following steps:

[0014] (1) Azeotropically distilling the butylamine raw material containing water under normal pressure to separate a first distillate and a first still residue, wherein the first distillate comprises azeotrope of n-butylamine and water;

[0015] (2) Azeotropically distilling the first distillate under pressure to separate a second distillate and a first target product, wherein the first target product is a first-grade n-butylamine product;

[0016] (3) Azeotropically distilling the second distillate after refluxing, together with the first still residue and the butylamine raw material containing water, under normal pressure to separate a third distillate and a third still residue, wherein the third still residue comprises n-butylamine, di-n-butylamine and tri-n-butylamine;

[0017] (4) Distilling the third still residue to separate a second target product, a third target product and a fourth target product, wherein the second target product is a second-grade n-butylamine product, the third target product is a di-n-butylamine product and the fourth target product is a tri-n-butylamine product;

[0018] The reaction conditions of steps (1) and (3) are selected from at least one of the following conditions (I) to (III) to make the content of n-butylamine in the third still residue equivalent to the content of tri-n-butylamine:

[0019] (I) The reflux ratio of azeotropically distilling under normal pressure in steps (1) and (3) is 1.6 to 3.0;

[0020] (II) The temperature of azeotropically distilling under normal pressure in step (1) is 43 to 63°C;

[0021] (III) The amount of the second distillate refluxed in step (3) is 535 kg / h to 2470 kg / h.

[0022] In an embodiment of the present application, the pressure under normal pressure in steps (1) and (3) is 60 to 200 KPaA.

[0023] In an embodiment of the present application, the reaction conditions of step (2) are selected from at least one of the following conditions (IV) to (V):

[0024] (IV) The pressure under pressure is 400 to 900 KPaA;

[0025] (V) The temperature of azeotropically distilling under pressure is 60 to 120°C.

[0026] In an embodiment of the present application, the reflux ratio of azeotropically distilling under pressure in step (2) is 1 to 10.

[0027] In an embodiment of the present application, the pressure of distilling in step (4) is 60 to 200 KPaA and the temperature is 70 to 120°C.

[0028] In an embodiment of the present application, the reflux ratio of the rectification in step (4) is 1-10.

[0029] In an embodiment of the present application, the rectification in step (4) is performed by using a dividing wall column.

[0030] In an embodiment of the present application, the purity of the primary n-butylamine product is greater than 99.8%, and the purity of the secondary n-butylamine product is greater than 99.5%.

[0031] The second aspect of the present application provides a separation and purification system for energy-coupled variable-pressure refining of n-butylamine, comprising a normal-pressure azeotropic column, a pressurized azeotropic column, a dividing wall column, a first channel, a second channel, a third channel, and a fifth channel. The normal-pressure azeotropic column is provided with a raw material inlet, and the first channel is a feed channel for the aqueous n-butylamine raw material, which is connected to the raw material inlet. The top of the normal-pressure azeotropic column is connected to the pressurized azeotropic column through the second channel. The top of the pressurized azeotropic column is connected to the normal-pressure azeotropic column through the third channel. The dividing wall column is provided with a feed side and a discharge side. The bottom of the normal-pressure azeotropic column is connected to the feed side through the fifth channel, and the top, side line, and bottom of the discharge side are respectively provided with product discharge channels.

[0032] In an embodiment of the present application, the product discharge channel at the top of the discharge side is a discharge channel for the secondary n-butylamine product.

[0033] The product discharge channel at the side line of the discharge side is a discharge channel for the secondary n-butylamine product.

[0034] The product discharge channel at the bottom of the discharge side is a discharge channel for the tertiary n-butylamine product.

[0035] The beneficial technical effects of the present application are as follows:

[0036] The present application performs a variable-pressure refining process of normal-pressure azeotropic rectification and pressurized azeotropic rectification on the aqueous n-butylamine raw material, and then performs rectification again by using a dividing wall column, thereby completing the separation and purification of the aqueous n-butylamine raw material by energy coupling, effectively removing water and other impurities that are azeotropic with n-butylamine, and obtaining industrial-grade n-butylamine, secondary n-butylamine, and tertiary n-butylamine products. Compared with the traditional n-butylamine separation process, the present application is suitable for aqueous n-butylamine raw material, and can greatly save energy consumption in the separation and purification process, and reduce equipment and operating investment.

[0037] Under the same raw material composition and product index, the application uses the separation and purification system and process to carry out pressurized azeotropic rectification on the azeotrope of n-butylamine and water, and carries out atmospheric azeotropic rectification again on the first stillage, the second distillate and the butylamine raw material containing water after refluxing the second distillate, by controlling at least one of the temperature, the reflux ratio of the atmospheric azeotropic rectification and the second distillate reflux amount, on the basis of significantly reducing the load of the equipment used in the atmospheric azeotropic rectification process, the n-butylamine content in the third stillage is ensured to be equivalent to the tri-n-butylamine content when the third stillage enters the dividing wall column, so as to better play the advantages of the dividing wall column, separate out butylamine products with high purity, and the energy consumption is reduced by 20% to 40% compared with the traditional rectification separation process.

[0038] In summary, the application uses the energy coupling refining of pressure swing azeotropic rectification and dividing wall column to complete the separation and purification of butylamine products containing water, compared with the traditional process, on the basis of obtaining high-purity n-butylamine, di-n-butylamine and tri-n-butylamine products, the equipment and operation cost is greatly reduced.

[0039] It should be understood that the above general description and the following detailed description are only exemplary and explanatory, and cannot limit the application. BRIEF DESCRIPTION OF DRAWINGS

[0040] In order to more clearly illustrate the technical solutions of the embodiments of the application, the following will briefly introduce the drawings needed to be used in the embodiments. It should be understood that the following drawings only show some embodiments of the application, and therefore should not be regarded as a limitation on the scope, and for those skilled in the art, other related drawings can also be obtained without creative labor on the basis of these drawings.

[0041] Figure 1 The schematic diagram of the separation and purification system of the energy coupling pressure refining butylamine of the application;

[0042] Figure 2 The schematic diagram of the dividing wall column of the application;

[0043] Figure 3 The schematic diagram of the existing tri-n-butylamine separation and purification device.

[0044] REFERENCE NUMERALS

[0045] T001: atmospheric azeotropic column; T002: pressurized azeotropic column; T003: dividing wall column; S1: first channel; S2: second channel; S3: third channel; S4: fourth channel; S5: fifth channel; S6: sixth channel; S7: seventh channel; S8: eighth channel; 301: common rectification section; 302: pre-separation column; 303: longitudinal partition; 304: common stripping section; 305: main column; 400: condenser. DETAILED DESCRIPTION

[0046] Unless otherwise defined, all technical and / or scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which the application pertains. It is to be understood that certain features that are, for clarity, described in the context of separate embodiments can also be provided in combination in a single embodiment. Conversely, various features that are, for brevity, described in the context of a single embodiment can also be provided separately or in any suitable combination. The use of numbering in the claims is intended to supplement, not supersede, a classification that is drawn in the description. Certain features that are, for brevity, described in the context of several embodiments, can also be provided in combination in a single embodiment. To the extent that certain features of the application, which are, for brevity, described in the context of several embodiments, are also applicable in combination to other embodiments, they are not to be interpreted as being removed from the scope of the application, from whatever specific context in which they are described. The following further describes the application by way of specific examples, but it is to be understood that the specific process conditions and results described in the examples of the embodiments of the application are for illustrative purposes only and are not to be construed as limiting the scope of the application, and that equivalent changes or modifications to the examples of the embodiments of the application made in accordance with the spirit of the application are to be included within the scope of the application.

[0047] The present application provides a separation and purification process for energy-coupled transformed butylamine, comprising the following steps:

[0048] (1) azeotropically distilling the butylamine raw material containing water under normal pressure to separate a first distillate and a first still residue, the first distillate comprising an azeotrope of n-butylamine and water;

[0049] (2) azeotropically distilling the first distillate under pressure to separate a second distillate and a first target product, the first target product being a first-grade n-butylamine product;

[0050] (3) refluxing the second distillate and then azeotropically distilling the refluxed second distillate together with the first still residue and the butylamine raw material containing water under normal pressure to separate a third distillate and a third still residue, the third still residue comprising n-butylamine, di-n-butylamine and tri-n-butylamine;

[0051] (4) rectifying the third still residue to separate a second target product, a third target product and a fourth target product, the second target product being a second-grade n-butylamine product, the third target product being a di-n-butylamine product and the fourth target product being a tri-n-butylamine product;

[0052] The reaction conditions of steps (1) and (3) are selected from at least one of the following conditions (I) to (III) so that the content of n-butylamine in the third still residue is equivalent to the content of tri-n-butylamine:

[0053] (I) the reflux ratio of the azeotropic distillation of steps (1) and (3) under normal pressure is 1.6 to 3.0;

[0054] (II) the temperature of the azeotropic distillation of step (1) under normal pressure is 43 to 63°C;

[0055] (III) Step (3) second fraction backflow is 535kg / h~2470kg / h.

[0056] Specifically, the pressure of step (1) and step (3) in the application is 60~200KPaA.

[0057] Specifically, the pressure of step (2) in the application is 400~900KPaA; the temperature of the pressurized azeotropic distillation is 60~120℃; the reflux ratio of the pressurized azeotropic distillation is 1~10.

[0058] Specifically, the pressure of step (4) in the application is 60~200KPaA, and the temperature is 70~120℃; the reflux ratio of the distillation is 1~10.

[0059] Specifically, the application adopts a dividing wall distillation column for the distillation of step (4).

[0060] Specifically, the purity of the primary n-butylamine product in the application is greater than 99.8%, and the purity of the secondary n-butylamine product is greater than 99.5%.

[0061] Specifically, the first fraction is azeotrope of high-concentration water and n-butylamine, the second fraction is azeotrope of low-concentration water and n-butylamine, and the third fraction is azeotrope of water and n-butylamine with a concentration between the first fraction and the second fraction. The first pot residue is a mixed material containing impurities after the first fraction of the water-containing butylamine raw material is separated.

[0062] The application provides a separation and purification system for energy-coupled pressure-changing butylamine refining, as shown in the figure, comprising an atmospheric azeotropic column T001, a pressurized azeotropic column T002, a dividing wall distillation column T003, a first channel S1, a second channel S2, a third channel S3, and a fifth channel S5. Figure 1 The atmospheric azeotropic column T001 is provided with a raw material inlet, and the first channel S1 is a feeding channel for the water-containing butylamine raw material, which is connected with the raw material inlet. The top of the atmospheric azeotropic column T001 is connected with the pressurized azeotropic column T002 through the second channel S2. The top of the pressurized azeotropic column T002 is connected with the atmospheric azeotropic column T001 through the third channel S3. The dividing wall distillation column T003 is provided with a feeding side and a discharging side. The column bottom of the atmospheric azeotropic column T001 is connected with the feeding side through the fifth channel S5, and the top, side line and column bottom of the discharging side are respectively provided with product discharging channels.

[0063] Specifically, the water-containing butylamine raw material in the application is a material containing n-butylamine, di-n-butylamine, tri-n-butylamine and water. In actual production, the water-containing butylamine raw material may also contain trace impurities, including butyl ether and the like.

[0064] The hydrous butylamine feedstock enters the atmospheric azeotropic tower T001 from the middle of the tower body through the first channel S1 for azeotropic distillation, separating the first fraction and the first batch residue. The first fraction is an azeotrope of water and n-butylamine with a high concentration, and the n-butylamine content in the azeotrope is about 97%.

[0065] The first fraction is collected from the top of the atmospheric azeotropic column T001 and enters the pressurized azeotropic column T002 through the second channel S2 for azeotropic distillation to separate the second fraction and the first target product, which is a first-grade n-butylamine product with a purity greater than 99.8%.

[0066] Specifically, the bottom of the pressurized azeotropic tower T002 is equipped with a fourth channel S4, which is the discharge channel for the first-grade n-butylamine product.

[0067] Specifically, the second fraction is collected from the top of the pressurized azeotropic tower T002 and recycled back to the atmospheric azeotropic tower T001 via the third channel S3. At this time, the atmospheric azeotropic tower T001 contains the first fraction, the first batch residue, and the continuously fed aqueous butylamine feedstock. Therefore, it is necessary to re-establish the gas-liquid balance parameters and control at least one of the following: the second fraction reflux rate, the reflux ratio of the atmospheric azeotropic tower T001, and the top temperature of the atmospheric azeotropic tower T001. This ensures that the n-butylamine content in the third batch residue collected from the bottom of the atmospheric azeotropic tower T001 is comparable to the tri-n-butylamine content, thereby reducing the energy consumption of the atmospheric azeotropic tower T001.

[0068] Specifically, such as Figure 2 As shown, the partitioned distillation column T003 of this application includes a longitudinal partition 303, a common rectification section 301, a pre-separation column 302, a common stripping section 304, a main column 305, and two condensers 400. The partitioned distillation column T003 is divided into a pre-separation column 302 and a main column 305 by the longitudinal partition 303 located in the middle. The pre-separation column 302 is the feed side, and the main column 305 is the discharge side. The product collection channel at the top of the main column 305 is the sixth channel S6, which serves as the discharge channel for secondary n-butylamine product with a purity greater than 99.5%. The product collection channel at the side of the main column 305 is the seventh channel S7, which serves as the discharge channel for di-n-butylamine product. The product collection channel at the bottom of the main column 305 is the eighth channel S8, which serves as the discharge channel for tri-n-butylamine product.

[0069] Specifically, the third still residue enters the pre-separation tower 302 from the middle of the feed side of the partition wall rectifying tower T003 through the fifth channel S5 for pre-separation. The partition wall rectifying tower T003 is thermodynamically equivalent to a completely thermally coupled rectifying tower. In the partition wall rectifying tower T003, the flow of the two phases in the tower relies on the reflux liquid provided by the condenser 400 and the gas evaporation provided by the reboiler (not shown in the figure) to be realized. The di-n-butylamine in the third still residue is pre-separated in the pre-separation tower 302 of the partition wall rectifying tower T003, part of which enters the common rectification section 301 from the upper end of the vertical partition 303 with light components, i.e. low-boiling-point mixture containing n-butylamine, and the other part enters the common distillation section 304 from the lower end of the vertical partition 303 with heavy components, i.e. high-boiling-point mixture containing tri-n-butylamine. The di-n-butylamine continues to separate in the common rectification section 301 and the common distillation section 304 and gradually enriches, thereby avoiding the mixing of the di-n-butylamine in the tower during separation, which causes energy waste. At the same time, the control of the gas-liquid phase distribution ratio ensures the gas-liquid phase balance and heat balance of the feed side (pre-separation tower 302) and the discharge side (main tower 305) of the partition wall rectifying tower T003, which achieves the purpose of energy saving while ensuring the separation efficiency.

[0070] Specifically, in the present application, the number of theoretical plates of the normal-pressure azeotropic tower T001 is 30-60; the number of theoretical plates of the pressurized azeotropic tower T002 is 30-60; and the number of theoretical plates of the partition wall rectifying tower T003 is 30-60.

[0071] Specifically, in the present application, the condenser 400 is arranged at the top of the normal-pressure azeotropic tower T001, the pressurized azeotropic tower T002 and the partition wall rectifying tower T003.

[0072] The separation and purification system and process for energy-coupled variable-pressure refined butylamine according to the present application are described in detail below.

[0073] The present application is described in detail below through specific examples. It should also be understood that the following examples are only used to specifically describe the present application and cannot be understood as limiting the protection scope of the present application. Some non-essential improvements and adjustments made by those skilled in the art according to the above content of the present application all belong to the protection scope of the present application. The specific process parameters and the like described below are only one example in the appropriate range, i.e. those skilled in the art can make appropriate selection within the range through the description herein, and are not limited to the specific values of the examples below.

[0074] The crude product still liquid obtained from an amine plant is used as the butylamine raw material for separation and purification according to the present application. The feed amount is controlled to be 10 t / h, the temperature is 120℃, and the pressure is 1.5 MPag. The composition of the crude product still liquid is detected as follows:

[0075]

[0076] wherein the light component is azeotrope of n-butylamine and water.

[0077] Example 1

[0078] The aqueous n-butylamine feedstock enters the middle of the column body from the first passage into the atmospheric azeotrope column, is azeotropically distilled, and separates into azeotrope of n-butylamine and water (first fraction) and first pot residue; the azeotrope is taken from the top of the atmospheric azeotrope column and enters the pressurized azeotrope column from the second passage, is azeotropically distilled, and separates into a first-stage n-butylamine product with a purity of greater than 99.8% and a second fraction; the first-stage n-butylamine product is taken from the fourth passage.

[0079] The second fraction is refluxed into the atmospheric azeotrope column from the third passage, is azeotropically distilled again with the first pot residue and the aqueous n-butylamine feedstock, and separates into third pot residue; the third pot residue enters the dividing wall column from the feed side from the fifth passage, is distilled, and separates into a second-stage n-butylamine product with a purity of greater than 99.5% taken from the sixth passage, a di-n-butylamine product with a purity of greater than 99.8% taken from the seventh passage, and a tri-n-butylamine product with a purity of greater than 99.5% taken from the eighth passage.

[0080] In the above separation process, the top temperature of the atmospheric azeotrope column is 63°C, the top temperature of the pressurized azeotrope column is 90°C, and the top temperature of the dividing wall column is 95°C.

[0081] The top pressure of the atmospheric azeotrope column is 76 KPaA, the top pressure of the pressurized azeotrope column is 600 KPaA, and the top pressure of the dividing wall column is 100 KPaA.

[0082] The reflux ratio of the atmospheric azeotrope column is 3.0, the reflux ratio of the pressurized azeotrope column is 0.9, and the reflux ratio of the dividing wall column is 2.9. The reflux amount of the first fraction is 2470 kg / h.

[0083] Example 2

[0084] The difference between this example and Example 1 is that:

[0085] The reflux ratio of the atmospheric azeotrope column is 2.8, the reflux ratio of the pressurized azeotrope column is 0.9, and the reflux ratio of the dividing wall column is 3.0.

[0086] Example 3

[0087] The difference between this example and Example 1 is that:

[0088] The reflux ratio of the atmospheric azeotrope column is 2.6, the reflux ratio of the pressurized azeotrope column is 1.0, and the reflux ratio of the dividing wall column is 3.1.

[0089] Example 4

[0090] The difference between this example and Example 1 is that:

[0091] The reflux ratio of the atmospheric azeotrope column is 2.4, the reflux ratio of the pressurized azeotrope column is 1.1, and the reflux ratio of the dividing wall rectification column is 3.2.

[0092] Example 5

[0093] The difference between this example and Example 1 is that:

[0094] The reflux ratio of the atmospheric azeotrope column is 2.2, the reflux ratio of the pressurized azeotrope column is 1.2, and the reflux ratio of the dividing wall rectification column is 3.3.

[0095] Example 6

[0096] The difference between this example and Example 1 is that:

[0097] The reflux ratio of the atmospheric azeotrope column is 2.0, the reflux ratio of the pressurized azeotrope column is 1.4, and the reflux ratio of the dividing wall rectification column is 3.4.

[0098] Example 7

[0099] The difference between this example and Example 1 is that:

[0100] The reflux ratio of the atmospheric azeotrope column is 1.8, the reflux ratio of the pressurized azeotrope column is 1.5, and the reflux ratio of the dividing wall rectification column is 3.5.

[0101] Example 8

[0102] The difference between this example and Example 1 is that:

[0103] The reflux ratio of the atmospheric azeotrope column is 1.6, the reflux ratio of the pressurized azeotrope column is 1.6, and the reflux ratio of the dividing wall rectification column is 3.6.

[0104] Example 9

[0105] The difference between this example and Example 1 is that:

[0106] The top temperature of the atmospheric azeotrope column is 61℃, and the reflux amount of the first fraction is 1860kg / h.

[0107] Example 10

[0108] The difference between this example and Example 1 is that:

[0109] The top temperature of the atmospheric azeotrope column is 59℃, and the reflux amount of the first fraction is 1340kg / h.

[0110] Example 11

[0111] The difference between this example and Example 1 is that:

[0112] The top temperature of the atmospheric azeotrope column is 55℃, and the reflux amount of the first fraction is 1090kg / h.

[0113] Example 12

[0114] The difference between this example and Example 1 is that:

[0115] The overhead temperature of the atmospheric azeotropic column is 52℃, and the reflux flow rate of the first fraction is 780kg / h.

[0116] Example 13

[0117] The difference between this example and Example 1 is that:

[0118] The overhead temperature of the atmospheric azeotropic column is 47℃, and the reflux flow rate of the first fraction is 650kg / h.

[0119] Example 14

[0120] The difference between this example and Example 1 is that:

[0121] The overhead temperature of the atmospheric azeotropic column is 43℃, and the reflux flow rate of the first fraction is 535kg / h.

[0122] Example 15

[0123] The difference between this example and Example 1 is that:

[0124] The reflux ratio of the atmospheric azeotropic column is 1.6, the reflux ratio of the pressurized azeotropic column is 1.6, and the reflux ratio of the dividing wall column is 3.6. The overhead temperature of the atmospheric azeotropic column is 43℃, and the reflux flow rate of the first fraction is 535kg / h.

[0125] Comparative Example 1

[0126] According to the device shown in Figure 2 The device is used to separate and purify butylamine products, and the same feed load as in the examples is used, except that the device uses two dividing wall columns for separation. The energy consumption of the two dividing wall columns calculated using the device is 2455kw and 1080kw, respectively.

[0127] The present application analyzes the results of Examples 1-15, and calculates the energy consumption of the atmospheric azeotropic column, the pressurized azeotropic column, and the dividing wall column of each example. The results are shown in the following table:

[0128]

[0129] By comparing the results of Examples 1-8, it can be found that by reducing the reflux ratio of the atmospheric azeotropic column, and ensuring that the content of n-butylamine and tri-n-butylamine entering the dividing wall column is equivalent, the advantages of the dividing wall column can be fully utilized, and the energy consumption of the separation and purification system is lower, and the investment cost is less.

[0130] By comparing the results of examples 9-14, it can be found that by reducing the first fraction backflow, reducing the overhead temperature of the atmospheric azeotropic tower, and gradually approaching the azeotrope, the energy consumption of the atmospheric azeotropic tower and the pressurized azeotropic tower can be lower.

[0131] By comparing the results of examples 1-15 and comparative example 1, it can be found that the energy consumption of the separation and purification system of the present application is less than that of the separation and purification device of the comparative example, thereby indicating that the separation and purification system and process based on the energy coupling variable pressure refining of butylamine of the present application can significantly reduce the energy consumption of the separation and purification system, and can be better applied to the separation and purification of industrial organic butylamine products.

[0132] The above examples only exemplarily illustrate the principles and effects of the present application, and are not used to limit the present application. Any person skilled in the art can modify or change the above examples without departing from the spirit and scope of the present application. Therefore, all equivalent modifications or changes completed by those skilled in the art without departing from the spirit and technical thought disclosed by the present application should be covered by the claims of the present application.

Claims

1. A separation and purification process for butylamine obtained by energy-coupled pressure swing refining, characterized in that, Includes the following steps: (1) The aqueous butylamine feedstock is subjected to azeotropic distillation under normal pressure to separate the first fraction and the first batch residue. The first fraction includes an azeotrope of n-butylamine and water. (2) The first fraction is subjected to azeotropic distillation under pressure to separate the second fraction and the first target product, wherein the first target product is a primary n-butylamine product; (3) After refluxing the second fraction, it is subjected to azeotropic distillation at atmospheric pressure together with the first batch residue and the aqueous butylamine raw material to separate the third fraction and the third batch residue, wherein the third batch residue includes n-butylamine, di-n-butylamine and tri-n-butylamine; (4) The third batch of residue is distilled using a partitioned distillation column to separate the second target product, the third target product, and the fourth target product. The second target product is a secondary n-butylamine product, the third target product is a di-n-butylamine product, and the fourth target product is a tri-n-butylamine product. The pressure at normal pressure in steps (1) and (3) is 60~200 kPaA, and the pressure of pressurization in step (2) is 400~900 kPaA; The reaction conditions in steps (1) and (3) are selected from at least one of the following conditions (I) to (III) so that the n-butylamine content in the third reactor residue is equivalent to the tri-n-butylamine content: (I) The reflux ratio of the azeotropic distillation under normal pressure in steps (1) and (3) is 1.6~3.0; (II) The temperature of the azeotropic distillation under normal pressure in step (1) is 43~63℃; (III) The reflux flow rate of the second fraction in step (3) is 535 kg / h to 2470 kg / h.

2. The separation and purification process according to claim 1, characterized in that, In step (2), the temperature of the pressurized azeotropic distillation is 60~120℃.

3. The separation and purification process according to claim 1, characterized in that, The reflux ratio of the pressurized azeotropic distillation in step (2) is 1~10.

4. The separation and purification process according to claim 1, characterized in that, The pressure of distillation in step (4) is 60~200 KPaA and the temperature is 70~120℃.

5. The separation and purification process according to claim 1, characterized in that, The reflux ratio for distillation in step (4) is 1 to 10.

6. The separation and purification process according to claim 1, characterized in that, The purity of the primary n-butylamine product is greater than 99.8%, and the purity of the secondary n-butylamine product is greater than 99.5%.

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