An acrylic acid rectification separation system and method

Abstract

The present application relates to a kind of acrylic acid rectification separation system and method, the three-tower separation process of light component removal tower, light component removal rectification tower and heavy component removal tower is used in the present application, and product acrylic acid is obtained by rectification separation.In the present application, light component removal is carried out to acrylic acid crude liquid by light component removal tower and light component removal rectification tower, which can effectively avoid the problems such as too many tray numbers, too high rectification tower, difficult equipment manufacturing and large engineering difficulty when single-tower separation is carried out in original light component removal tower;The process in the present application can flexibly adjust the tray numbers of two towers to improve the removal efficiency of light components of acrylic acid and the recovery rate of acrylic acid, overcome the shortcomings of too high tower height of single tower, or avoid the problems such as affecting the recovery rate of acrylic acid and the light component removal efficiency due to too few tray numbers;At the same time, power equipment is added between the gas phase streams of light component removal tower and light component removal rectification tower in the present application, the pressure of rectification tower is controlled separately, thereby having the advantages of avoiding bottom polymerization and high condensation temperature at the top of tower.

Description

Technical Field

[0001] This invention relates to the field of acrylic acid production technology, specifically to an acrylic acid distillation and separation system and method. Background Technology

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

[0003] Acrylic acid has gone through an era where various preparation methods coexisted. Acrylonitrile hydrolysis, high-pressure Ryp process (high-pressure carbonyl synthesis), modified Ryp process (low-pressure carbonyl synthesis), cyanoethanol process, and ketene process were all once the main methods for producing acrylic acid and its esters. However, these methods have been largely phased out due to severe equipment corrosion, high energy consumption, low yield, and high cost. Currently, the most commonly used method for producing acrylic acid is the propylene oxidation process. In the propylene oxidation process for producing acrylic acid, the separation of various substances such as organic hydrocarbons, water, acrylic acid, acetic acid, and heavy components in the product gas is quite difficult.

[0004] Currently, in the product gas separation technology of propylene oxidation to acrylic acid production plants, the separation of acrylic acid and water mainly employs azeotropic separation technology using toluene, cyclohexane, or other media as azeotropic agents, or extraction separation technology using methyl isobutyl ketone or other media as extractants. These separation technologies require the introduction of additional azeotropic agents or extractants, resulting in complex processes, high energy consumption, and a large number of equipment. For example, in patent CN10260036B, the separation of acrylic acid product gas mainly involves azeotropic distillation using an azeotropic agent; patents CN1241892C and CN1546453A use extractive distillation to separate acrylic acid, acetic acid, and water. These separation processes also suffer from complex processes, high energy consumption, and a large number of equipment. Patent CN102775295A employs a dual-tower distillation method (absorption tower and purification tower) to separate acrylic acid, acetic acid, and water. While this technology reduces the number of towers, the product purity is relatively low. To improve the purity of the acrylic acid, the number of trays in the purification tower needs to be increased, which can lead to excessively high tower height and significant overall pressure drop. Since the purification tower condenses the lighter components at the top and the acrylic acid and heavier components at the bottom, the operating pressure of the purification tower is crucial. Excessive pressure and bottom temperature can easily lead to acrylic acid polymerization, while insufficient pressure can result in insufficient condensation temperature at the top, placing stricter requirements on refrigeration quality. Therefore, although the solution in patent CN102775295A requires fewer pieces of equipment, it suffers from significant acrylic acid loss, low acrylic acid purity, and susceptibility to polymerization at the bottom of the tower. Summary of the Invention

[0005] The technical problem to be solved by the present invention is to provide an acrylic acid distillation separation system and method that can improve the removal efficiency of light components of acrylic acid and the recovery rate of acrylic acid, and reduce the polymerization problems of acrylic acid and heavy components, in light of the existing technology.

[0006] The technical solution adopted by the present invention to solve the above-mentioned technical problems is as follows:

[0007] An acrylic acid distillation separation system, comprising:

[0008] The light component removal distillation column is used to distill and separate crude acrylic acid liquor. It has an inlet for inputting the crude acrylic acid liquor, a first outlet at the top for outputting the obtained light component, and a second outlet at the bottom for outputting the obtained heavy component.

[0009] A light component removal distillation column is located downstream of the light component removal distillation column and is used to perform distillation separation on the gas phase output from the first outlet of the light component removal distillation column. The bottom of the light component removal distillation column is provided with an inlet connected to the first outlet of the light component removal distillation column. The bottom of the light component removal distillation column is provided with a return pipeline for returning the obtained acrylic acid distillate to the light component removal distillation column. The top of the light component removal distillation column is provided with an outlet for outputting the obtained light component.

[0010] The heavy component removal tower, located downstream of the light component removal distillation tower, is used for distillation separation of the liquid phase output from the second outlet of the light component removal distillation tower. The middle part of the heavy component removal tower is provided with an inlet connected to the second outlet of the light component removal distillation tower. The heavy components output from the second outlet of the light component removal distillation tower are transported to the heavy component removal tower under the power provided by the bottom pump of the light component removal distillation tower. The top of the heavy component removal tower is provided with a first outlet for the output of the obtained acrylic acid product gas, and the bottom of the heavy component removal tower is provided with a second outlet for the output of the obtained heavy components. The pipeline connected to the second outlet is equipped with a heavy component pump that provides power for the output of the heavy components.

[0011] Preferably, the bottom inlet of the light-light distillation column is connected to the first outlet of the light-light stripping column via a feed pipeline, which is equipped with a pressurization system that can pressurize the conveyed material.

[0012] Preferably, the pressurization system is a power equipment system that pressurizes the gas phase at the top of the light-removal distillation column and sends it to the bottom of the light-removal rectification column, and can be any one of a vacuum pump, compressor, or blower.

[0013] Preferably, the return pipeline is equipped with a light distillation tower reflux pump for providing power to the reflux material.

[0014] Preferably, the bottom of the light-weight stripping column is connected in series with a light-weight stripping column reboiler and a light-weight stripping column reboiler circulation pump.

[0015] Preferably, the top of the light-weight distillation column is equipped with a light-weight distillation column condenser, a light-weight distillation column reflux tank, and a light-weight distillation column reflux pump. The light-weight distillation column condenser is used to condense the gas phase output from the top of the light-weight distillation column and reflux it back to the light-weight distillation column reflux tank. The light-weight distillation column reflux pump is used to provide power for the reflux of part of the condensate.

[0016] Preferably, the top of the light-distillation distillation column reflux tank is provided with an output route for the tail gas to the flare system, and the bottom of the light-distillation distillation column reflux tank is provided with a discharge pipeline for a portion of the acetic acid-containing wastewater to be discharged under the drive of the acetic acid wastewater pump.

[0017] Preferably, the top of the deweighting column is equipped with a deweighting column top condenser, a deweighting column reflux tank, and a deweighting column reflux pump connected in series. The deweighting column top condenser is used to condense the gas phase output from the top of the deweighting column and reflux it back to the deweighting column reflux tank. The deweighting column reflux pump is used to provide power for the reflux of part of the condensate. Downstream of the deweighting column reflux tank, an output pipeline for acrylic acid products is provided.

[0018] Preferably, the bottom of the deweighting column is connected in series with a deweighting column reboiler and a deweighting column reboiler circulation pump.

[0019] An acrylic acid distillation separation method includes the following steps:

[0020] The crude acrylic acid liquor obtained after water washing and rapid cooling absorption first enters the light component removal distillation tower. In the light component removal distillation tower, the crude acrylic acid liquor is distilled and separated to separate all the light components. The bottom of the tower yields a concentrated acrylic acid liquor containing only the heavy components.

[0021] The gas phase at the top of the light component stripping column is pressurized and enters the bottom of the light component stripping distillation column. The light component is separated by distillation in the light component stripping distillation column and all the light components are discharged from the top of the distillation column. The non-condensable tail gas is sent to the flare system, while the acetic acid wastewater obtained can be recycled as the washing liquid for acrylic acid product gas in the upstream process.

[0022] The acrylic acid distillate from the bottom of the light-light distillation column is returned to the light-light stripping column via a reflux pump, thus completing the light-light removal process of the crude acrylic acid. The concentrated acrylic acid is then further fed into the heavy-weight component removal column, where it is separated by distillation. Acrylic acid is obtained at the top of the column, while the heavy-weight component waste liquid is sent to the subsequent treatment system.

[0023] In this invention, the light component removal distillation column is used to separate and distill crude acrylic acid, removing all light components from the acrylic acid. The bottom of the light component removal distillation column is a concentrated solution of acrylic acid and its heavy components after the light components have been removed. The overall operating temperature of the light component removal distillation column is 30–110°C, and the operating pressure is -0.10 MPaG to -0.07 MPaG; the theoretical plate number of the light component removal distillation column is 5–60. The light component removal rectification distillation column is used to separate acrylic acid and its light components by rectification, collecting the light components from the top of the column, and condensing and recovering most of the acrylic acid. The overall operating temperature of the light component removal rectification distillation column is 30–110°C, and the operating pressure is -0.10 MPaG to -0.05 MPaG; the theoretical plate number of the light component removal distillation column is 5–60. The heavy component removal column is used to separate the concentrated acrylic acid solution by rectification, obtaining the acrylic acid product at the top of the column, and the heavy components at the bottom of the column are sent to the subsequent processing system. The operating pressure of the debinding and recombining tower is -0.010 to -0.07 MPaG.

[0024] Compared with the prior art, the advantages of the present invention are as follows: the present invention adopts a three-tower separation process of light component stripping tower, light component rectification tower and heavy component stripping tower, and obtains the product acrylic acid through rectification separation. In this invention, a light component removal distillation column and a light component removal rectification column are used to remove light components from the crude acrylic acid liquor. This effectively avoids the problems of excessive number of trays, excessively tall rectification columns, difficult equipment manufacturing, and high engineering difficulty associated with the original light component removal column's single-column separation. The process in this invention allows for flexible adjustment of the number of trays in both columns to improve the removal efficiency of light components and the recovery rate of acrylic acid, overcoming the disadvantage of excessively tall single columns, or avoiding the problem of insufficient trays affecting the recovery rate of acrylic acid and the efficiency of light component removal. At the same time, this invention adds power equipment between the gaseous streams of the light component removal distillation column and the light component removal rectification column to achieve independent control of the rectification column pressure. This allows for adjustment of the operating pressure of the light component removal distillation column and the light component removal rectification column. By increasing the operating pressure of the light component removal rectification column, the condensing temperature at the top of the rectification column can be increased, reducing the demand for cooling capacity. By decreasing the operating pressure of the light component removal distillation column, the operating temperature of the column bottom can be reduced, thereby reducing the polymerization of acrylic acid with heavy components.

[0025] Compared to azeotropic or extractive distillation processes, this invention has the advantages of a shorter and simpler process flow; and compared to a two-tower distillation process, this invention has the advantages of a single-tower height, higher acrylic acid purity, and higher acrylic acid recovery rate. Specifically:

[0026] This invention employs a dual-tower separation method, consisting of a light component removal distillation tower and a light component removal stripping tower, to separate the light components from the crude acrylic acid solution. This method can improve the removal efficiency of light components in acrylic acid, ensure the yield and purity of acrylic acid products, and flexibly adjust the number of trays in the light component removal distillation tower and the light component removal stripping tower. This avoids problems such as excessively high single-tower height, excessive pressure drop between the top and bottom of a single tower, and high engineering difficulty when separating light components in acrylic acid. It has advantages such as high acrylic acid purity and controllable distillation tower height.

[0027] This invention, by setting up a pressurization system on the gaseous stream between the light-weight stripping column and the light-weight rectification column, allows for flexible control of the operating pressures of both columns. The advantages of controllable pressure between the two columns are: the operating pressure of the stripping column can be appropriately reduced to prevent excessively high temperatures at the bottom of the light-weight stripping column from causing acrylic acid polymerization; the operating pressure of the rectification column can be appropriately increased to raise the condensation temperature at the top of the light-weight rectification column, reducing the requirement for low-temperature cooling. Thus, the pressurization system achieves controllable pressure in the rectification units of both the light-weight stripping and light-weight rectification columns, avoids bottom polymerization problems, and achieves high condensation temperatures. Attached Figure Description

[0028] Figure 1 This is a process flow diagram of Embodiment 1 of the present invention;

[0029] Figure 2 This is a process flow diagram of Embodiment 2 of the present invention. Detailed Implementation

[0030] The present invention will be further described in detail below with reference to the accompanying drawings and embodiments.

[0031] Example 1:

[0032] like Figure 1 As shown, the acrylic acid distillation separation system of this embodiment includes:

[0033] Light component removal distillation column 1 is used for distillation and separation of crude acrylic acid liquor. It has an inlet for inputting crude acrylic acid liquor, a first outlet at the top for outputting the obtained light component, and a second outlet at the bottom for outputting the obtained heavy component. A light component removal distillation column reboiler 9 and a light component removal distillation column reboiler circulation pump 10 are connected in series at the bottom of the column.

[0034] Light component removal distillation column 6 is located downstream of light component removal distillation column 1 and is used to perform distillation separation on the gas phase output from the first outlet of light component removal distillation column 1. The bottom of light component removal distillation column 6 is provided with an inlet connected to the first outlet of light component removal distillation column 1. The bottom of light component removal distillation column 6 is provided with a return pipeline for returning the obtained acrylic acid distillate to the light component removal distillation column. The return pipeline is provided with a light component removal distillation column reflux pump 2 for providing power to the reflux material. The top of light component removal distillation column 6 is provided with an outlet for outputting the obtained light components.

[0035] The heavy component removal tower 14 is located downstream of the light component removal tower 1 and is used for distillation separation of the liquid phase output from the second outlet of the light component removal tower 1. The heavy component removal tower 14 has an inlet connected to the second outlet of the light component removal tower 1 in the middle. The heavy components output from the second outlet of the light component removal tower 1 are transported to the heavy component removal tower 14 under the power provided by the light component removal tower bottom pump 11. The top of the heavy component removal tower 14 is provided with a first outlet for the output of the obtained acrylic acid product gas, and the bottom of the heavy component removal tower 14 is provided with a second outlet for the output of the obtained heavy components. The pipeline connected to the second outlet is equipped with a heavy component pump 18 that provides power for the output of the heavy components. The bottom of the heavy component removal tower 14 is connected in series with a heavy component removal tower reboiler 16 and a heavy component removal tower reboiler circulation pump 17.

[0036] In this embodiment, the bottom inlet of the light-light distillation column 6 is connected to the first outlet of the light-light stripping column 1 via a feed pipeline. This feed pipeline is equipped with a pressurization system 3 that can pressurize the conveyed material. The pressurization system 3 is a power equipment system that pressurizes the gas phase at the top of the light-light stripping column 1 and sends it to the bottom of the light-light distillation column 6.

[0037] The top of the light-weight distillation column 6 is connected in series with a light-weight distillation column condenser 4, a light-weight distillation column reflux tank 5, and a light-weight distillation column reflux pump 8. The light-weight distillation column condenser 4 is used to condense the gas phase output from the top of the light-weight distillation column 6 and reflux it back to the light-weight distillation column reflux tank 5. The light-weight distillation column reflux pump 8 is used to provide power for the reflux of part of the condensate. The top of the light-weight distillation column reflux tank 5 is provided with an output route for the tail gas to the flare system, and the bottom of the light-weight distillation column reflux tank 5 is provided with a discharge pipeline for the discharge of part of the acetic acid-containing wastewater driven by the acetic acid wastewater pump 7.

[0038] The top of the deweighting column 14 is connected in series with a deweighting column top condenser 12, a deweighting column reflux tank 13, and a deweighting column reflux pump 15. The deweighting column top condenser 12 is used to condense the gas phase output from the top of the deweighting column 14 and reflux it back to the deweighting column reflux tank 13. The deweighting column reflux pump 15 is used to provide power for the reflux of part of the condensate. Downstream of the deweighting column reflux tank 13, there is an output pipeline for the output of acrylic acid products.

[0039] The acrylic acid distillation separation method of this embodiment includes the following steps:

[0040] The crude acrylic acid liquor obtained after water washing and rapid cooling absorption first enters the light component removal distillation tower. In the light component removal distillation tower, the crude acrylic acid liquor is distilled and separated to separate all the light components. The bottom of the tower yields a concentrated acrylic acid liquor containing only the heavy components.

[0041] The gas phase at the top of the light component stripping column is pressurized and enters the bottom of the light component stripping distillation column. The light component is separated by distillation in the light component stripping distillation column and all the light components are discharged from the top of the distillation column. The non-condensable tail gas is sent to the flare system, while the acetic acid wastewater obtained can be recycled as the washing liquid for acrylic acid product gas in the upstream process.

[0042] The acrylic acid distillate from the bottom of the light-light distillation column is returned to the light-light stripping column via a reflux pump, thus completing the light-light removal process of the crude acrylic acid. The concentrated acrylic acid is then further fed into the heavy-weight component removal column, where it is separated by distillation. Acrylic acid is obtained at the top of the column, while the heavy-weight component waste liquid is sent to the subsequent treatment system.

[0043] In this embodiment, the light component removal distillation column is used to separate and distill the crude acrylic acid solution, removing all light components from the acrylic acid. The bottom of the light component removal distillation column is a concentrated solution of acrylic acid and its heavy components after the light components have been removed. The overall operating temperature of the light component removal distillation column is 30–110°C, and the operating pressure is -0.10 MPaG to -0.07 MPaG; the theoretical plate number of the light component removal distillation column is 5–60. The light component removal rectification distillation column is used to separate acrylic acid and its light components by rectification, collecting the light components from the top of the column, and condensing and recovering most of the acrylic acid. The overall operating temperature of the light component removal rectification distillation column is 30–110°C, and the operating pressure is -0.10 MPaG to -0.05 MPaG; the theoretical plate number of the light component removal distillation column is 5–60. The heavy component removal column is used to separate the concentrated acrylic acid solution by rectification, obtaining the acrylic acid product at the top of the column, and the heavy components at the bottom of the column are sent to the subsequent processing system. The operating pressure of the debinding and recombining tower is -0.010 to -0.07 MPaG.

[0044] The process scheme for an annual production capacity of 100,000 tons of acrylic acid will be used as an example for explanation:

[0045] The crude acrylic acid liquor (40–80℃, 0.01–0.30 MPaG, containing 35–75 wt% acrylic acid) from upstream at a rate of 16–24 t / h first enters the light component removal distillation column 1. In column 1, the crude acrylic acid liquor undergoes distillation and separation, removing all light components. The bottom of the column yields a concentrated acrylic acid liquor (80–98 wt% acrylic acid) containing only heavy components at a rate of 12–15 t / h. The operating pressure of the light component removal distillation column is between -0.10 MPaG and -0.07 MPaG, the theoretical number of plates is 30, and the overall operating temperature is between 30 and 110℃. The vapor phase from the top of the light component stripping column 1 enters the bottom of the light component stripping distillation column 6 via the pressurization system 3. Distillation separation occurs within the column, removing all light components from the top. The non-condensable tail gas is sent to the flare system, while the resulting acetic acid wastewater can be recycled as washing liquid for the acrylic acid product gas in the upstream process. The operating temperature of the light component stripping distillation column 6 is between 30 and 110°C, and the operating pressure is between -0.10 MPaG and -0.05 MPaG. The column has 30 theoretical plates. The acrylic acid distillate from the bottom of the column 6 is returned to the light component stripping column 1 via the reflux pump 8, completing the light component stripping process for the entire acrylic acid crude liquid. The concentrated acrylic acid solution is further fed into the heavy component stripping column 14, where it undergoes distillation separation. Acrylic acid is obtained at the top, while the heavy component waste liquid at the bottom is sent to the subsequent treatment system. The theoretical number of trays in the debinding column 14 is 30 to 70, and the operating pressure is between -0.010 and -0.07 MPaG.

[0046] Generally, the total number of trays in a light component removal distillation column and a light component removal stripping column is between 60 and 100. In practice, the feed location of the crude acrylic acid solution is determined by the content of light components in the solution to be separated. Then, based on the temperature between the trays, the number of trays in the light component removal distillation column and the light component removal stripping column is determined. In this embodiment, the theoretical number of trays in both the light component removal stripping column and the light component removal distillation column is set to 30 to improve the removal efficiency of light components in acrylic acid and the recovery rate of acrylic acid. Based on a 100,000-ton / year propylene oxidation to acrylic acid plant, using the technical solution of this invention, compared to the traditional acrylic acid separation process, one distillation column and its auxiliary equipment can be reduced, ensuring a acrylic acid recovery rate of over 98.5% and an acrylic acid purity of over 99.5%.

[0047] Example 2:

[0048] The difference between this embodiment and Embodiment 1 is that: Figure 2As shown, the pressurization equipment between the light-weight distillation column and the light-weight stripping column is eliminated. This process still has the advantages of fewer trays per column, varying column heights, and ease of manufacturing and engineering of individual column equipment. It also features high purity acrylic acid and high acrylic acid recovery. However, after eliminating the additional equipment, the pressure between the two columns is interconnected and cannot be controlled independently. Therefore, problems such as bottom polymerization and low top condensation temperature cannot be avoided. Nevertheless, this process has the advantages of a shorter process flow and fewer pieces of equipment.

Claims

1. An acrylic acid distillation and separation system, characterized in that... include: The light component removal distillation column is used to distill and separate crude acrylic acid liquor. It has an inlet for inputting the crude acrylic acid liquor, a first outlet at the top for outputting the obtained light component, and a second outlet at the bottom for outputting the obtained heavy component. A light component removal distillation column is located downstream of the light component removal distillation column and is used to perform distillation separation on the gas phase output from the first outlet of the light component removal distillation column. The bottom of the light component removal distillation column is provided with an inlet connected to the first outlet of the light component removal distillation column. The bottom of the light component removal distillation column is provided with a return pipeline for returning the obtained acrylic acid distillate to the light component removal distillation column. The top of the light component removal distillation column is provided with an outlet for outputting the obtained light component. A heavy component removal tower is located downstream of the light component removal distillation tower and is used to perform distillation separation on the liquid phase output from the second outlet of the light component removal distillation tower. The middle part of the heavy component removal tower is provided with an inlet connected to the second outlet of the light component removal distillation tower. The top of the heavy component removal tower is provided with a first outlet for the output of the obtained acrylic acid product gas, and the bottom of the heavy component removal tower is provided with a second outlet for the output of the obtained heavy components. The bottom inlet of the light-light distillation column is connected to the first outlet of the light-light stripping column via a feed pipeline, which is equipped with a pressurization system that can pressurize the conveyed material; the return pipeline is equipped with a light-light stripping column reflux pump for providing power to the reflux material. The bottom of the light-weight stripping column is connected in series with a light-weight stripping column reboiler and a light-weight stripping column reboiler circulation pump.

2. The acrylic acid distillation and separation system according to claim 1, characterized in that: The pressurization system is a power equipment system that pressurizes the gas phase at the top of the light-removal distillation column and sends it to the bottom of the light-removal rectification column. It can be any one of a vacuum pump, compressor, or blower.

3. The acrylic acid distillation and separation system according to claim 1 or 2, characterized in that: The top of the light-weight distillation column is connected in series with a light-weight distillation column condenser, a light-weight distillation column reflux tank, and a light-weight distillation column reflux pump. The light-weight distillation column condenser is used to condense the gas phase output from the top of the light-weight distillation column and reflux it back to the light-weight distillation column reflux tank. The light-weight distillation column reflux pump is used to provide power for the reflux of part of the condensate.

4. The acrylic acid distillation and separation system according to claim 3, characterized in that: The top of the reflux tank of the light-light distillation column is provided with an output route for the tail gas to the flare system, and the bottom of the reflux tank of the light-light distillation column is provided with a discharge pipeline for a portion of the acetic acid-containing wastewater to be discharged under the drive of the acetic acid wastewater pump.

5. The acrylic acid distillation and separation system according to claim 1 or 2, characterized in that: The top of the deweighting column is equipped with a deweighting column top condenser, a deweighting column reflux tank, and a deweighting column reflux pump. The deweighting column top condenser is used to condense the gas phase output from the top of the deweighting column and reflux it back to the deweighting column reflux tank. The deweighting column reflux pump is used to provide power for the reflux of part of the condensate. Downstream of the deweighting column reflux tank, an output pipeline for acrylic acid products is provided.

6. The acrylic acid distillation and separation system according to claim 1 or 2, characterized in that: The bottom of the deweighting column is connected in series with a deweighting column reboiler and a deweighting column reboiler circulation pump.

7. A method for distilling and separating acrylic acid, characterized in that, The acrylic acid distillation separation system according to any one of claims 1 to 6 includes the following steps: The crude acrylic acid liquor obtained after water washing and rapid cooling absorption first enters the light component removal distillation tower. In the light component removal distillation tower, the crude acrylic acid liquor is distilled and separated to separate all the light components. The bottom of the tower yields a concentrated acrylic acid liquor containing only the heavy components. The gas phase at the top of the light component stripping column is pressurized and enters the bottom of the light component stripping distillation column. The light component is separated by distillation in the light component stripping distillation column and all the light components are discharged from the top of the distillation column. The non-condensable tail gas is sent to the flare system, while the acetic acid wastewater obtained can be recycled as the washing liquid for acrylic acid product gas in the upstream process. The acrylic acid distillate from the bottom of the light-light distillation column is returned to the light-light stripping column via a light-light distillation column reflux pump, thus realizing the light-light removal process of the entire acrylic acid crude liquid. The acrylic acid concentrate is then further sent to the heavy-weight component removal column, where it is separated by distillation. The product acrylic acid is obtained at the top of the column, while the heavy-weight component waste liquid is sent to the subsequent treatment system. The light-light stripping column operates at a temperature of 30~110℃ and a pressure of -0.10MPaG~-0.07MPaG; the light-light stripping column has 5~60 theoretical plates. The overall operating temperature of the light-weight distillation column is 30~110℃, and the operating pressure is -0.10MPaG~-0.05MPaG; the theoretical number of plates in the light-weight distillation column is 5~60. The operating pressure of the debinding and recombining tower is -0.010 to -0.07 MPaG.

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