Acrylic acid rectification separation device

Abstract

The invention provides an acrylic acid rectification separation device, which comprises: a quenching absorption tower for carrying out quenching treatment on an acrylic acid product gas to form an acrylic acid crude solution; the acrylic acid refining tower is arranged at the downstream of the quenching absorption tower, and the acrylic acid crude solution is introduced from the quenching absorption tower; the acrylic acid refining tower is a dividing wall tower, is internally provided with a separation partition plate, and is used for rectifying and separating the acrylic acid crude solution to obtain a light component, an acrylic acid product and a heavy component. The device has the beneficial effects that the separation of the acrylic acid product gas is realized through the quenching absorption tower and the acrylic acid refining tower with the built-in separation partition plate.

Description

Technical Field

[0001] The invention relates to the technical field of acrylic acid production, in particular to an acrylic acid rectification and separation device. Background Art

[0002] As an important organic chemical raw material, acrylic acid is widely used in the production of adhesives and water-soluble coatings. It plays an important role in the fields of chemical fiber, papermaking, leather, building materials, plastic modification, synthetic rubber, radiation-cured water treatment agents, etc. It can also be processed into butyl acrylate, etc.

[0003] Acrylic acid has experienced a period of coexistence of various preparation methods. Acrylonitrile hydrolysis, high-pressure Rep method (high-pressure carbonyl synthesis method), improved Rep method (low-pressure carbonyl synthesis method), cyanoethanol method, ketene method, etc. have all been used as the main methods for producing acrylic acid and esters. However, these methods have been basically eliminated due to factors such as severe equipment corrosion, high energy consumption, low yield, and high cost. Currently, the most commonly used method for producing acrylic acid is propylene oxidation. In the separation process of the propylene oxidation method for producing acrylic acid, it is difficult to separate various substances such as organic hydrocarbons, water, acrylic acid, acetic acid, and heavy components in the product gas.

[0004] In the existing product gas separation technology of propylene oxidation to acrylic acid device, it mainly adopts azeotropic separation technology using toluene, cyclohexane and other media as azeotropic agents, or extractive separation technology using methyl isobutyl ketone and other media as extractants. However, the above separation technology solutions require the introduction of additional azeotropic agents or extractants for separation, which has problems such as complex process flow, high energy consumption, and a large number of equipment. Based on this, existing researchers have proposed double-tower distillation separation and three-tower separation technology for acrylic acid. For example, the Chinese invention patent with publication number CN102775295A discloses a method for purifying acrylic acid, which uses an absorption tower and a purification tower double-tower distillation to achieve the separation of acrylic acid, acetic acid and water. However, in this process scheme, although the number of equipment is small, there are problems such as large acrylic acid loss and low acrylic acid purity. For another example, the Chinese utility model patent with publication number CN218834066U discloses a new separation system for an acrylic acid device, which adopts a three-tower separation technology to efficiently absorb and separate the acrylic acid product gas and obtain the product acrylic acid, simplifying the process flow and improving the purity of the acrylic acid product. However, this separation technology still has room for further optimization in terms of energy saving optimization, technical improvement, etc.

[0005] Therefore, it is necessary to study an acrylic acid distillation separation device to solve the above problems or alleviate the impact of the above problems. Summary of the invention

[0006] The invention provides an acrylic acid rectification and separation device, which realizes the separation of acrylic acid product gas through a quenching absorption tower and an acrylic acid refining tower with a separation partition built in.

[0007] The acrylic acid distillation and separation device of the present invention may include: a quenching absorption tower, which is used to quench the acrylic acid product gas and form a crude acrylic acid solution; an acrylic acid refining tower, which is arranged downstream of the quenching absorption tower and introduces the crude acrylic acid solution from the quenching absorption tower; the acrylic acid refining tower is a dividing wall tower, which is provided with a separation partition, and the acrylic acid refining tower is used to distill and separate the crude acrylic acid solution to obtain light components, acrylic acid products and heavy components.

[0008] In one embodiment, the separation baffle is vertically installed in the acrylic acid refining tower, and the separation baffle at least divides the interior of the acrylic acid refining tower into a pre-separation zone and a product extraction zone, and the pre-separation zone and the product extraction zone are respectively located on both sides of the separation baffle.

[0009] In one embodiment, the acrylic acid refining tower is provided with an inlet for the acrylic acid crude solution corresponding to the pre-separation zone, and the acrylic acid refining tower is provided with an outlet for the acrylic acid product corresponding to the product extraction zone.

[0010] In one embodiment, the separation baffle is located at the lower position of the acrylic acid refining tower, the lower end of the separation baffle abuts against the bottom of the acrylic acid refining tower, and the upper end of the separation baffle to the top of the acrylic acid refining tower forms a common distillation zone.

[0011] In one embodiment, the separation baffle is located in the middle of the acrylic acid refining tower, and the upper end of the separation baffle to the top of the acrylic acid refining tower forms a common distillation zone, and the lower end of the separation baffle to the bottom of the acrylic acid refining tower forms a common stripping zone.

[0012] In one embodiment, the separation baffle is located at the upper part of the acrylic acid refining tower, the upper end of the separation baffle abuts against the top of the acrylic acid refining tower, and the lower end of the separation baffle to the bottom of the acrylic acid refining tower form a common distillation zone.

[0013] In one embodiment, the separation device further comprises a kettle liquid quenching circulation system disposed at the bottom of the quenching absorption tower, and the kettle liquid quenching circulation system comprises a circulating pump for providing power and a cooler for refrigeration that are connected.

[0014] In one embodiment, the separation device further comprises an acetic acid wastewater recovery system connected to the top of the acrylic acid refining tower, and the acetic acid wastewater recovery system comprises a condenser for refrigeration, a reflux tank for storing liquid, and a water pump for providing power, which are sequentially connected.

[0015] In one embodiment, the separation device further comprises the acrylic acid recovery system connected to the bottom of the acrylic acid refining tower, and the acrylic acid recovery system is used to perform depolymerization reaction and distillation separation on the heavy component.

[0016] In one embodiment, a heavy component reboiler is disposed at the bottom of the acrylic acid refining tower, and the heavy component reboiler is used to heat the heavy component at the bottom of the acrylic acid refining tower.

[0017] Compared with the prior art, the acrylic acid distillation separation device provided by the present invention has at least the following features:

[0018] Beneficial effects:

[0019] The acrylic acid refining tower of the acrylic acid distillation separation device of the present invention adopts a dividing wall tower, and the light component, acrylic acid product and heavy component in the acrylic acid crude solution can be separated by a single tower. In this way, the acrylic acid product gas can be separated by two towers, namely, the quenching absorption tower and the acrylic acid refining tower, thereby reducing the number of equipment such as distillation towers, condensers and reboilers in the separation process of the acrylic acid product gas, simplifying the process flow, reducing equipment investment, and having the characteristics of low energy consumption, high economic benefits and the like. BRIEF DESCRIPTION OF THE DRAWINGS

[0020] Hereinafter, the present invention will be described in more detail based on embodiments and with reference to the accompanying drawings.

[0021] Figure 1 1 is a schematic structural diagram of an acrylic acid distillation separation device according to an embodiment of the present invention;

[0022] Figure 2 is another structural schematic diagram of an acrylic acid distillation separation device according to an embodiment of the present invention;

[0023] Figure 3 It is another structural schematic diagram of the acrylic acid distillation separation device according to an embodiment of the present invention.

[0024] In the drawings, the same reference numerals are used for the same components. The drawings are not drawn to scale.

[0025] Reference numerals:

[0026] 1-quenching absorption tower, 2-acrylic acid refining tower, 3-heavy component reboiler, 4-condenser, 5-reflux tank, 6-acrylic acid reboiler, 7-water pump, 8-acrylic acid recovery system, 9-cooler, 10-circulation pump, 11-separation partition, 12-acrylic acid condenser, 13-acrylic acid reflux tank, 14-acrylic acid pump. DETAILED DESCRIPTION

[0027] The present invention will be further described below in conjunction with the accompanying drawings.

[0028] Figure 1 It is a structural schematic diagram of an acrylic acid distillation separation device when a separation partition is arranged at the lower part of an acrylic acid refining tower; Figure 2 It is a structural schematic diagram of an acrylic acid distillation separation device when a separation partition is arranged in the middle of an acrylic acid refining tower; Figure 3 It is a structural schematic diagram of an acrylic acid distillation separation device when a separation partition is arranged on the upper part of an acrylic acid refining tower.

[0029] like Figures 1 to 3 As shown, the acrylic acid distillation and separation device of the present invention may include: a quenching absorption tower 1, used for quenching the acrylic acid product gas and forming a crude acrylic acid solution; an acrylic acid refining tower 2, which is arranged downstream of the quenching absorption tower 1 and introduces the crude acrylic acid solution from the quenching absorption tower 1; the acrylic acid refining tower 2 is a dividing wall tower, which is provided with a separation partition 11, and the acrylic acid refining tower 2 is used for distilling and separating the crude acrylic acid solution to obtain light components, acrylic acid products and heavy components.

[0030] Specifically, the top of the quench absorption tower 1 uses circulating acetic acid-containing wastewater and fresh desalted water as absorbents to quench and absorb and separate the acrylic acid product gas entering the quench absorption tower 1, absorb and separate the acrylic acid and non-condensable gas in the acrylic acid product gas, and obtain a crude acrylic acid solution and tail gas, the tail gas is discharged from the tail gas outlet at the top of the tower to the waste gas treatment system, and the crude acrylic acid solution flows from the crude acrylic acid solution outlet at the bottom of the tower to the acrylic acid refining tower 2. The crude acrylic acid solution enters the acrylic acid refining tower 2 from the crude acrylic acid solution inlet, and multi-component distillation separation is achieved by relying on the built-in separation partition 11 to obtain light components (including non-condensable gas, water, acetic acid, etc.), acrylic acid products and heavy components, and the light components are output from the corresponding outlets at the top of the tower, the acrylic acid products are output from the corresponding outlets on the tower wall, and the heavy components are output from the corresponding outlets at the bottom of the tower.

[0031] In general, the acrylic acid refining tower 2 of the acrylic acid distillation separation device of the present invention adopts a dividing wall tower, and the light components, acrylic acid products and heavy components in the acrylic acid crude solution can be separated by a single tower. In this way, the separation of the acrylic acid product gas can be achieved through the quenching absorption tower 1 and the acrylic acid refining tower 2, which reduces the number of equipment such as distillation towers and reboilers in the separation process of the acrylic acid product gas, simplifies the process flow, reduces equipment investment, and has the characteristics of low energy consumption and high economic benefits.

[0032] It should be noted that the temperature of acrylic acid product gas is generally 40-200°C and the pressure is 0.01-0.30 MPaG. The operating pressure of the quench absorption tower 1 is generally 0-0.5 MPaG. The operating pressure of the acrylic acid refining tower 2 is generally -0.099--0.05 MPaG.

[0033] In one example, the separation baffle 11 is vertically set up in the acrylic acid refining tower 2, and the separation baffle 11 at least divides the interior of the acrylic acid refining tower 2 into a pre-separation area and a product extraction area, and the pre-separation area and the product extraction area are respectively located on both sides of the separation baffle 11. The pre-separation area is the area where the acrylic acid crude solution just enters the acrylic acid refining tower 2, and is used to perform preliminary separation of the acrylic acid crude solution. The product extraction area is the main gathering area of ​​the acrylic acid product formed after the acrylic acid crude solution is distilled and separated, and this area can directly transport the acrylic acid product to the outside.

[0034] It should be noted that the vertical position of the separation baffle 11 in the acrylic acid refining tower 2 can be set at the upper part, the middle part or the lower part of the tower, and the horizontal position of the separation baffle 11 can be set at the center of the tower, the left part of the center of the tower, or the right part of the center of the tower. The feeding position of the acrylic acid crude solution in the acrylic acid refining tower 2 changes according to the position change of the separation baffle 11, including the upper part, the middle part and the lower part of the acrylic acid refining tower 2. At the same time, the extraction position of the acrylic acid product can include the side line extraction, the bottom extraction and the top extraction of the acrylic acid refining tower 2. The corresponding best method is selected for different design schemes.

[0035] In one example, the acrylic acid refining tower 2 is provided with an inlet for the acrylic acid crude solution in the corresponding pre-separation zone, and the acrylic acid refining tower 2 is provided with an outlet for the acrylic acid product in the corresponding product extraction zone.

[0036] like Figure 1 As shown, in one example, the separation baffle 11 is located at the lower part of the acrylic acid refining tower 2, the lower end of the separation baffle 11 abuts against the bottom of the acrylic acid refining tower 2, and the upper end of the separation baffle 11 to the top of the acrylic acid refining tower 2 forms a common distillation zone.

[0037] Specifically, the acrylic acid crude solution is first fed from the lower part of the acrylic acid refining tower 2 and the left side of the separation partition 11. Through the distillation separation action, the heavy component is extracted from the tower bottom outlet of the left area (pre-separation area) of the separation partition 11, and the acrylic acid product reaches the right area (product extraction area) of the separation partition 11 from the upper end of the separation partition 11 and is extracted from the outlet of this area. The common distillation area is used to separate the light component and the acrylic acid product, and the light component is extracted from the corresponding outlet at the top of the acrylic acid refining tower 2.

[0038] It should be noted that when the acrylic acid product is extracted from the right side of the separation partition 11, considering the problem that acrylic acid is easy to polymerize, the acrylic acid product can be extracted by side line extraction and bottom extraction. The acrylic acid product adopts the bottom extraction method, and the acrylic acid refining tower 2 can be provided with an acrylic acid reboiler 6 at the bottom corresponding to the product extraction area, which is used to heat and strip the acrylic acid product extracted from the bottom to avoid polymerization of acrylic acid in the tower bottom.

[0039] like Figure 2As shown, in one example, the separation baffle 11 is located in the middle of the acrylic acid refining tower 2, and the upper end of the separation baffle 11 to the top of the acrylic acid refining tower 2 forms a common distillation zone, and the lower end of the separation baffle 11 to the bottom of the acrylic acid refining tower 2 forms a common stripping zone.

[0040] Specifically, the acrylic acid crude solution is first fed from the middle of the acrylic acid refining tower 2 and the left side of the separation baffle 11. Through the distillation separation effect, the acrylic acid product and the heavy component enter the lower area (common distillation area) of the separation baffle 11, and the acrylic acid product and the light component enter the upper area (common distillation area) of the separation baffle 11. The acrylic acid product enters the right area (product extraction area) of the separation baffle 11 from the upper and lower ends of the separation baffle 11. The public distillation area is used to separate the light component and the acrylic acid product, and the light component is extracted from the corresponding outlet at the top of the acrylic acid refining tower 2. The public distillation area is used to separate the heavy component and the acrylic acid product, and the heavy component is extracted from the corresponding outlet at the bottom of the acrylic acid refining tower 2. The acrylic acid product adopts the side line extraction method, which can not only ensure the purity of acrylic acid, but also avoid the problem of easy polymerization of acrylic acid in the tower kettle.

[0041] It should be noted that the separation baffle 11 is arranged in the middle position of the acrylic acid refining tower 2, compared with being arranged in the lower position thereof, so that a kettle reboiler connected to the acrylic acid refining tower 2 can be omitted, thereby simplifying the process flow. However, according to the thermodynamic separation characteristics, the number of separation plates of the acrylic acid refining tower 2 may be increased.

[0042] like Figure 3 As shown, in one example, the separation baffle 11 is located at the upper position of the acrylic acid refining tower 2, the upper end of the separation baffle 11 abuts against the top of the acrylic acid refining tower 2, and the lower end of the separation baffle 11 to the bottom of the acrylic acid refining tower 2 forms a common distillation zone.

[0043] Specifically, the acrylic acid crude solution is first fed from the upper part of the acrylic acid refining tower 2 and the left side of the separation partition 11. Through the distillation separation effect, the acrylic acid product and the heavy component enter the lower area (common distillation area) of the separation partition 11. The common distillation area is used to separate the heavy component and the acrylic acid product. The heavy component is extracted from the corresponding outlet at the bottom of the acrylic acid refining tower 2. The acrylic acid product enters the right area (product extraction area) of the separation partition 11 from the lower end of the separation partition 11, and then is extracted from the corresponding outlet at the top of the acrylic acid refining tower 2. The acrylic acid product adopts the top extraction method, which not only ensures the purity of acrylic acid, but also avoids the problem of easy polymerization of acrylic acid in the tower kettle. The light component in the acrylic acid crude solution is extracted from the top of the acrylic acid refining tower 2 and the left side of the separation partition 11.

[0044] Furthermore, the outlet of the acrylic acid product at the top of the acrylic acid refining tower 2 is connected to an acrylic acid product liquid recovery system, which includes an acrylic acid condenser 12 for refrigeration, an acrylic acid reflux tank 13 for storing liquid, and an acrylic acid pump 14 for providing power, which are connected in sequence.

[0045] Specifically, the acrylic acid product liquid recovery system can introduce the acrylic acid product extracted from the top of the acrylic acid refining tower 2. The acrylic acid product is condensed by the acrylic acid condenser 12 and stored in the acrylic acid reflux tank 13. After the acrylic acid product liquid is pressurized by the acrylic acid pump 14, a part of it is returned to the acrylic acid refining tower 2, and the other part is output as the acrylic acid product.

[0046] It should be noted that the separation baffle 11 is arranged at the upper position of the acrylic acid refining tower 2, which can save a reboiler compared to setting it at the lower position, but requires an additional condenser. However, extracting the acrylic acid product from the top of the tower can effectively ensure the purity of the acrylic acid product and reduce the heavy components. However, according to the characteristics of thermodynamic separation, the number of separation plates of the acrylic acid refining tower 2 may be increased.

[0047] In one example, the separation device further includes a kettle liquid quenching circulation system disposed at the bottom of the quenching absorption tower 1, and the kettle liquid quenching circulation system includes a circulating pump 10 for providing power and a cooler 9 for refrigeration that are connected.

[0048] Specifically, the kettle liquid quenching circulation system can introduce the crude acrylic acid solution from the bottom of the quenching absorption tower 1. After passing through the cooler 9 and the circulation pump 10, the crude acrylic acid solution flows back into the quenching absorption tower 1 to quench and absorb the acrylic acid product gas.

[0049] In one example, the separation device further includes an acetic acid wastewater recovery system connected to the top of the acrylic acid refining tower 2, and the acetic acid wastewater recovery system includes a condenser 4 for refrigeration, a reflux tank 5 for storing liquid, and a water pump 7 for providing power, which are connected in sequence.

[0050] Specifically, the acetic acid wastewater recovery system can introduce light components extracted from the top of the acrylic acid refining tower 2. After the light components are condensed by the condenser 4, the non-condensed gas is sent to the flare emission system or the waste gas treatment system as tail gas. The condensed acetic acid-containing wastewater is formed and stored in the reflux tank 5. After the acetic acid-containing wastewater is pressurized by the water pump 7, a part of it is returned to the acrylic acid refining tower 2, and the other part is returned to the quenching absorption tower 1 as circulating absorption water.

[0051] In one example, the separation device further includes an acrylic acid recovery system 8 connected to the bottom of the acrylic acid refining tower 2, and the acrylic acid recovery system 8 is used to perform depolymerization reaction and distillation separation on the heavy component. The acrylic acid recovery system 8 can introduce the heavy component from the acrylic acid refining tower 2, and through reaction, distillation and other methods, the acrylic acid in the heavy component is recycled and returned to the acrylic acid refining tower 2 for product refining, and the heavy component after recycling is sent to the subsequent waste liquid treatment system. In this way, acrylic acid can be recovered and the yield of acrylic acid products can be improved.

[0052] In one example, a heavy component reboiler 3 is disposed at the bottom of the acrylic acid refining tower 2 , and the heavy component reboiler 3 is used to heat the heavy component at the bottom of the acrylic acid refining tower 2 .

[0053] Specifically, when the separation baffle 11 in the acrylic acid refining tower 2 is at the lower position, the heavy component reboiler 3 and the acrylic acid reboiler 6 are respectively arranged on both sides of the separation baffle 11 and heat and strip the corresponding tower bottom materials. The heavy component reboiler 3 and the acrylic acid reboiler 6 can be of the type of falling film evaporator, thin film evaporator, thermosyphon reboiler, kettle reboiler, etc.

[0054] It should also be noted that, considering that the acrylic acid product gases of different devices are different, the quenching absorption temperature in the quenching absorption tower 1, the horizontal and vertical positions of the separation partition 11 in the acrylic acid refining tower 2, the various extraction volumes, reflux ratios, tail gas circulation ratios, etc. all have different optimal values ​​and need to be set according to actual conditions.

[0055] In order to better understand the above embodiments, the present invention will be further described below by taking a 100,000 tons / year propylene oxidation to acrylic acid plant as an example.

[0056] The acrylic acid product gas (90.3t / hr, 170℃, 0.03MPaG) from the reaction system after waste heat recovery first enters the quenching absorption tower 1, and the bottom kettle liquid of the quenching absorption tower 1 is cooled and circulated to the lower section of the quenching absorption tower 1 as the quenching absorption liquid through the circulating pump 10 and the cooler 9 to achieve the quenching absorption of the product gas. In order to reduce the loss of acrylic acid products in the tail gas, the circulating acetic acid-containing wastewater is introduced into the top of the quenching absorption tower 1. After the acrylic acid product gas is absorbed and separated, the crude acrylic acid solution is obtained at the bottom of the quenching absorption tower 1 and enters the acrylic acid refining tower 2. The operating pressure of the quenching absorption tower 1 is 0.01-0.02MpaG. The acrylic acid refining tower 2 adopts a dividing wall tower, and a separation partition 11 is set in the acrylic acid refining tower 2 to achieve multi-component separation of the acrylic acid crude solution in a single tower. In this scheme, the separation baffle 11 is set at the lower part of the acrylic acid refining tower 2, and the heavy component reboiler 3 and the acrylic acid reboiler 6 are respectively set on both sides of the separation baffle 11 at the bottom of the acrylic acid refining tower 2. The crude acrylic acid solution is first fed from the lower part of the acrylic acid refining tower 2 and the left side of the separation baffle 11. Through the distillation separation, the heavy component is extracted from the left side of the separation baffle 11 at the bottom of the acrylic acid refining tower 2, and then sent to the acrylic acid recovery system 8. In this case, the total number of theoretical plates of the acrylic acid refining tower 2 is 65, of which the number of theoretical plates corresponding to the two sides of the separation baffle 11 is 20, and the number of theoretical plates corresponding to the space above the separation baffle 11 is 45. In the design of this case, the horizontal position of the separation baffle 11 is more suitable for the cross-sectional area of ​​the left side of the separation baffle 11 to account for 65% of the cross-sectional area of ​​the lower tower of the acrylic acid refining tower 2. The operating pressure of the acrylic acid refining tower 2 is -0.099~-0.05MPaG. The acrylic acid product (13.2t / h) is extracted from the right side of the separation partition 11 at the bottom of the acrylic acid refining tower 2. Considering the problem of easy polymerization of acrylic acid, the acrylic acid product can be extracted by side line extraction and bottom extraction. The light components in the acrylic acid crude solution (including non-condensable gas, water, acetic acid, etc.) are extracted from the top of the acrylic acid refining tower 2. After condensation by the condenser 4, the non-condensable gas is sent to the flare emission system or the waste gas treatment system as tail gas. The condensed liquid is pressurized by the water pump 7 through the reflux tank 5 and partially returned to the acrylic acid refining tower 2, and the other part is returned to the quenching absorption tower 1 as circulating absorption water (6.9t / h). In the acrylic acid recovery system 8, the acrylic acid in the heavy component is recycled and returned to the acrylic acid refining tower 2 for product refining through reaction, distillation and other methods. The heavy component after recovery is sent to the subsequent waste liquid treatment system.

[0057] Based on a 100,000 tons / year propylene oxidation to acrylic acid device, after adopting the technical solution of the present invention, compared with the traditional acrylic acid separation process, three distillation towers and their ancillary equipment can be reduced in terms of equipment, energy consumption can be saved by 30-70%, and 0.6-1.5t of steam can be saved per ton of acrylic acid product, while ensuring that the recovery rate of acrylic acid products is greater than 99% and the purity of acrylic acid is greater than 99.6%.

[0058] In summary, the beneficial effects of the acrylic acid distillation separation device of the present invention include the following:

[0059] (1) The present invention uses a quenching absorption tower and an acrylic acid refining tower to separate the acrylic acid product gas, thereby obtaining an acrylic acid product, which has the characteristics of advanced process flow, high product purity, high product yield, small number of equipment, low investment, small footprint, low energy consumption and high economic benefits.

[0060] (2) The acrylic acid refining tower of the present invention adopts a dividing wall tower, and separates the light components (such as non-condensable gas, acetic acid, etc.) in the acrylic acid crude solution, the acrylic acid product and the heavy components through a single distillation tower, while reducing the number of corresponding auxiliary equipment (condenser, reboiler, pump), greatly simplifying the process flow, reducing equipment investment, and reducing the area occupied by the device.

[0061] (3) The present invention adopts dividing wall tower technology, which can effectively improve the energy utilization efficiency in the distillation process, reduce the load of the condenser and reboiler, reduce steam consumption, and achieve energy saving and emission reduction in the device compared with the traditional sequential separation process.

[0062] (4) The acrylic acid refining tower of the present invention adopts a dividing wall tower, which is separated on both sides of the partition, which helps to separate acrylic acid from light components and heavy components, overcomes the problems of low acrylic acid purity and high impurity content in the single-tower side extraction technology, and combines the side extraction and bottom extraction of acrylic acid products. It has the characteristics of high acrylic acid product purity and controllable product purity.

[0063] (5) The acetic acid-containing wastewater at the top of the acrylic acid refining tower of the present invention can be directly circulated as the absorption liquid of the quenching absorption tower, thereby reducing the loss rate of acrylic acid in the quenching absorption tower. The heavy components are partially recycled through the acrylic acid recovery system. Such a process design effectively ensures the operational stability of the acrylic acid distillation system, reduces the loss of acrylic acid products, and achieves a high yield of acrylic acid products.

[0064] Although the present invention has been described with reference to preferred embodiments, various modifications may be made thereto and parts thereof may be replaced by equivalents without departing from the scope of the present invention. In particular, the various technical features mentioned in the various embodiments may be combined in any manner as long as there are no structural conflicts. The present invention is not limited to the specific embodiments disclosed herein, but includes all technical solutions falling within the scope of the claims.

Claims

1. An acrylic acid distillation separation device, characterized in that: The separation device comprises: A quenching absorption tower is used to quench the acrylic acid product gas and form a crude acrylic acid solution; The acrylic acid refining tower is arranged downstream of the quenching absorption tower, and the acrylic acid crude solution is introduced from the quenching absorption tower; the acrylic acid refining tower is a dividing wall tower, which is provided with a separation partition, and is used to distill and separate the acrylic acid crude solution to obtain light components, acrylic acid products and heavy components.

2. The acrylic acid distillation separation device according to claim 1, characterized in that: The separation baffle is vertically set up in the acrylic acid refining tower, and the separation baffle at least divides the interior of the acrylic acid refining tower into a pre-separation zone and a product extraction zone, and the pre-separation zone and the product extraction zone are respectively located on both sides of the separation baffle.

3. The acrylic acid distillation separation device according to claim 2, characterized in that: The acrylic acid refining tower is provided with an inlet for the acrylic acid crude solution corresponding to the pre-separation zone, and the acrylic acid refining tower is provided with an outlet for the acrylic acid product corresponding to the product extraction zone.

4. The acrylic acid distillation separation device according to claim 3, characterized in that: The separation baffle is located at the lower part of the acrylic acid refining tower, the lower end of the separation baffle abuts against the bottom of the acrylic acid refining tower, and the upper end of the separation baffle to the top of the acrylic acid refining tower forms a common distillation zone.

5. The acrylic acid distillation separation device according to claim 3, characterized in that: The separation baffle is located in the middle of the acrylic acid refining tower, and a common distillation zone is formed from the upper end of the separation baffle to the top of the acrylic acid refining tower, and a common stripping zone is formed from the lower end of the separation baffle to the bottom of the acrylic acid refining tower.

6. The acrylic acid distillation separation device according to claim 3, characterized in that: The separation baffle is located at the upper part of the acrylic acid refining tower, the upper end of the separation baffle abuts against the top of the acrylic acid refining tower, and the lower end of the separation baffle to the bottom of the acrylic acid refining tower form a common distillation zone.

7. The acrylic acid distillation separation device according to any one of claims 1 to 6, characterized in that: The separation device also includes a kettle liquid quenching circulation system arranged at the bottom of the quenching absorption tower, and the kettle liquid quenching circulation system includes a circulating pump for providing power and a cooler for refrigeration that are connected.

8. The acrylic acid distillation separation device according to any one of claims 1 to 6, characterized in that: The separation device also includes an acetic acid wastewater recovery system connected to the top of the acrylic acid refining tower, and the acetic acid wastewater recovery system includes a condenser for refrigeration, a reflux tank for storing liquid, and a water pump for providing power, which are connected in sequence.

9. The acrylic acid distillation separation device according to any one of claims 1 to 6, characterized in that: The separation device further comprises the acrylic acid recovery system connected to the bottom of the acrylic acid refining tower, and the acrylic acid recovery system is used for performing depolymerization reaction and rectification separation on the heavy component.

10. The acrylic acid distillation separation device according to any one of claims 1 to 6, characterized in that: A heavy component reboiler is provided at the bottom of the acrylic acid refining tower, and the heavy component reboiler is used to heat the heavy component at the bottom of the acrylic acid refining tower.

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