System and method for recovering by-products in acetylacetone production process

Abstract

The invention discloses a system and a method for recovering by-products in an acetylacetone production process, the interior of a rectifying tower is sequentially divided into four separation sections from top to bottom along the height direction, and the four separation sections are respectively a T1 heavy component removal section, a T2 hydrolysis reaction and water separation section, a T3 continuous hydrolysis reaction separation section and a T4 low-boiling-point component separation section; the rectifying tower is provided with three feed ports and two discharge ports, the three feed ports are respectively a K1 feed port, a K2 feed port and a K3 feed port, and the two discharge ports are respectively a K4 recovered low-boiling-point substance outlet and a K5 acetic acid outlet. According to the invention, the recovery process is integrated, so that two streams of materials are subjected to preliminary separation and rectification in the same rectification tower and hydrolysis reaction at the same time, heat released by the reaction can provide heat for rectification, and meanwhile, the reaction consumes water of the system, so that the materials can be recovered well, steam is saved, and the energy consumption is reduced. And the effects of saving energy and reducing consumption are achieved.

Description

Technical Field

[0001] This invention relates to the field of by-product recovery technology, and in particular to a by-product recovery system and method in the production of acetylacetone. Background Technology

[0002] Industrially, acetylacetone is primarily produced from acetic acid and acetone. First, acetic acid is dehydrated at high temperature to obtain ketene. Then, ketene and acetone react under a catalyst to produce isopropyl acetate. Isopropyl acetate undergoes repositioning under a catalyst and high temperature to yield crude acetylacetone. Finally, the crude product is separated by distillation to obtain the final acetylacetone. Due to the complex production process, many intermediate materials are generated, all of which require purification and recycling. However, the methods for material recycling vary from company to company.

[0003] During acetic acid cracking, a large amount of acetic anhydride and diketene are produced in the condensate from the final quench cooler and vacuum pump. Typically, these two substances are hydrolyzed together to obtain acetic acid and acetone, which are then purified and recovered by distillation. In the process of producing crude acetylacetone from isopropyl acetate via transposition, some water vapor is added to the transposition furnace. Due to the large number of byproducts and incomplete transposition, the crude acetylacetone obtained from the transposition furnace outlet contains impurities such as acetic acid, acetone, isopropyl acetate, water, and butanone. The usual technical method is to feed these substances together into the first distillation column for separation. The material exiting from the top of the column is called the low-boiling point, while the bottom yields acetylacetone and high-boiling point. Since the low-boiling point at the top of the column still contains water, and isopropyl acetate and butanone azeotropically react with water, conventional distillation methods are insufficient to separate the useful substances, resulting in material waste. Summary of the Invention

[0004] The purpose of this invention is to overcome the shortcomings of existing technologies and provide a byproduct recovery system and method in the production of acetylacetone. This invention has the advantages of improving byproduct separation efficiency, reducing resource waste, and lowering costs.

[0005] This invention is achieved through the following technical solution: A byproduct recovery system for acetylacetone production includes a distillation column, a top condenser, and a bottom reboiler. The distillation column is divided into four separation sections from top to bottom along the height direction: T1 is the section for removing heavy components, T2 is the section for hydrolysis reaction and water separation, T3 is the section for continued hydrolysis reaction separation, and T4 is the section for separating low-boiling-point components. The distillation column is provided with three feed inlets and two discharge outlets. The three feed inlets are K1 feed inlet, K2 feed inlet and K3 feed inlet, and the two discharge outlets are K4 low-boiling-point recovery outlet and K5 acetic acid outlet. The K1 feed port is used to introduce acetic anhydride and diketene, and the K1 feed port is correspondingly located on the side wall of the distillation column between the T1 decomposition and recombinant removal section and the T2 hydrolysis reaction and water separation section. The K2 feed inlet is used to introduce low-boiling substances (acetic acid, isopropyl acetate, acetone, butanone, and water), and the K2 feed inlet is correspondingly located on the side wall of the distillation column between the T2 hydrolysis reaction and water separation section and the T3 continued hydrolysis reaction and separation section; The K3 feed inlet is a water replenishment inlet, and the K3 feed inlet is located on the side wall of the distillation column between the T3 continued hydrolysis reaction separation section and the T4 low-boiling-point component separation section. The K4 outlet for recovering low-boiling substances is located at the top of the distillation column, and the K5 outlet for acetic acid is located at the bottom of the distillation column; The top condenser is connected to the top of the distillation column; the bottom reboiler is connected to the bottom of the distillation column.

[0006] The low-boiling substances include acetic acid, isopropyl acetate, acetone, butanone, and water.

[0007] The T1 decomposition and recombination section, the T2 hydrolysis reaction and water separation section, the T3 continued hydrolysis reaction and separation section, and the T4 low-boiling-point component separation section are all equipped with packing structures or tray structures to enhance material contact.

[0008] The packing structure is any one or more combinations of corrugated packing structure, wire mesh packing structure or stepped ring packing structure, and the tray structure is a tray structure such as sieve tray tower or floating valve tower.

[0009] A method for recovering byproducts during acetylacetone production includes the following steps: (1) Introduce acetic anhydride and diketene into the distillation column through the K1 feed port, and introduce low-boiling substances into the distillation column through the K2 feed port. Start the bottom reboiler and the top condenser. (2) In the T1 section for removing heavy components, the acetic anhydride and diketene introduced into the K1 feed inlet are treated to remove heavy components to prevent the material from entering the top area of ​​the tower. (3) In the low-boiling substances introduced through the K2 inlet, water, isopropyl acetate, butanone, and acetone move upward under the action of steam, while acetic anhydride and diketene introduced through the K1 inlet move downward due to their higher boiling points. After they come into contact, acetic anhydride reacts with water to produce acetic acid and moves towards the lower part of the distillation column, while diketene reacts with water to produce acetone and carbon dioxide and moves towards the upper part of the distillation column. (4) The material enters the T3 hydrolysis reaction separation section and water is added through the K3 feed port so that the incompletely hydrolyzed acetic anhydride and diketene continue to undergo hydrolysis reaction with water; (5) The material enters the T4 low-boiling-point component separation section to remove the acetone generated in the T3 hydrolysis reaction separation section and the added water, ensuring that the acetic acid obtained from the bottom of the distillation column is almost free of water and acetone. (6) Collect the water-free low-boiling-point substances discharged from the top of the distillation column through the K4 low-boiling-point recovery outlet and send them to the next stage for separation and purification; collect the acetic acid discharged from the bottom of the distillation column that does not contain low-boiling-point substances through the K5 acetic acid outlet.

[0010] After starting the reboiler at the bottom of the column in step (1), the temperature inside the distillation column is controlled to increase in a gradient from top to bottom along the height of the distillation column.

[0011] In step (6), the vapor discharged from the top of the distillation column is condensed by the top condenser and then the low-boiling-point substances are collected through the K4 low-boiling-point recovery outlet.

[0012] The T1 section packing or tray structure is used to prevent acetic anhydride, acetic acid, diketene, and water from moving to the top of the distillation column. The packing or tray structure in the T2 hydrolysis reaction and water separation section, under the action of steam, causes the low-boiling-point substances such as isopropyl acetate, acetone, butanone, and water introduced through the K2 inlet to migrate to the top of the distillation column, and causes the high-boiling-point substances such as acetic anhydride and diketene introduced through the K1 inlet to move to the bottom of the distillation column. The hydrolysis reaction of acetic anhydride, diketene, and water is achieved through the contact of the packing. The packing or tray structure in the T3 hydrolysis reaction separation section, through the water added at the K3 inlet, allows the incompletely hydrolyzed acetic anhydride and diketene to continue hydrolysis under the contact action of the packing. The packing or tray structure in the T4 low-boiling-point component separation section is used to remove acetone generated by the hydrolysis reaction and excess water added by the K3 feed inlet, ensuring that the acetic acid output from the bottom of the distillation column is almost free of water and acetone.

[0013] The advantages of this invention are: This invention addresses the specific characteristics of the materials to be recovered (acetic anhydride and diketene can undergo hydrolysis with water, and the hydrolysis process also releases heat), integrating the recovery process so that the recovery of acetic anhydride, diketene, and low-boiling-point substances is initially separated in the same distillation column. Simultaneously, the hydrolysis reaction occurs, and the exothermic reaction provides heat for the distillation. At the same time, the reaction consumes the system's water content, ultimately achieving both effective material recovery and steam conservation, thus achieving energy saving and consumption reduction.

[0014] This invention achieves efficient hydrolysis and separation of by-products by setting up a segmented distillation column structure and multi-stage feed inlets, solving the problems of difficult separation and incomplete hydrolysis of low-boiling azeotropic systems in traditional processes. It has the advantages of improving by-product separation efficiency and reducing resource waste. Attached Figure Description

[0015] Figure 1 This is a schematic diagram of the structure of the present invention. Detailed Implementation

[0016] The technical solutions of this invention will now be clearly and completely described with reference to the accompanying drawings. Obviously, the described embodiments are merely some, not all, of the embodiments of this invention. The components of this invention described and shown in the accompanying drawings can generally be arranged and designed in various different configurations. Therefore, the following detailed description of the embodiments of the invention provided in the drawings is not intended to limit the scope of the claimed invention, but merely to illustrate selected embodiments of the invention. All other embodiments obtained by those skilled in the art based on the embodiments of this invention without inventive effort are within the scope of protection of this invention.

[0017] It should be noted that similar reference numerals and letters in the following figures indicate similar items; therefore, once an item is defined in one figure, it does not need to be further defined and explained in subsequent figures. Furthermore, in the description of this invention, terms such as "first," "second," etc., are used only to distinguish descriptions and should not be construed as indicating or implying relative importance.

[0018] In existing technologies, the low-boiling-point substances generated during the production of acetylacetone contain components such as acetic acid, isopropyl acetate, acetone, methyl ethyl ketone (MEK), and water. Due to the presence of azeotropic reactions, conventional distillation methods are insufficient to effectively separate these substances, leading to resource waste. For example, isopropyl acetate forms an azeotrope with water, and MEK also tends to form an azeotrope with water. While it's possible to use a vapor film separation method to remove the water before distillation, this would require significant investment in steam and vapor film equipment. This prevents traditional distillation from achieving low-cost recovery of each component, resulting in a large amount of low-boiling-point substances being treated as waste, increasing production costs and environmental burden.

[0019] To address the aforementioned issues, a system capable of simultaneously achieving hydrolysis and distillation separation needs to be designed. This system would break the azeotropic effect by controlling the reaction and separation processes in stages. Considering the tendency of acetic anhydride and diketene to hydrolyze into acetic acid and acetone at high temperatures, the hydrolysis reaction can be integrated with the distillation column structure. Temperature gradients in different separation sections can be used to promote synergistic reactions and separations. Simultaneously, multi-inlet stratified feeding ensures countercurrent contact of materials within the column, preventing heavy components from entering the top region and ensuring unreacted substances continue hydrolysis in subsequent separation sections.

[0020] Therefore, this invention proposes a byproduct recovery system for the acetylacetone production process, such as... Figure 1 As shown, it includes a distillation column 1, a top condenser 2, and a bottom reboiler 3; The distillation column 1 is divided into four separation sections from top to bottom along its height: T1 (removal of heavy components), T2 (hydrolysis reaction and water separation), T3 (continued hydrolysis reaction separation), and T4 (low-boiling-point component separation). The T1 section removes heavy components to prevent high-boiling-point substances from migrating to the top of the column, achieving initial separation through the counter-current flow of reflux and rising steam. The T2 section carries away light components from low-boiling-point substances through rising steam, while simultaneously promoting the contact reaction of acetic anhydride, diketene, and water. The T3 section extends the reaction time by adding water, ensuring the complete conversion of incompletely hydrolyzed substances. The T4 section removes residual acetone and water using a temperature gradient, maintaining the purity of the acetic acid in the bottom of the column.

[0021] The distillation column 1 is provided with three feed inlets and two discharge outlets. The three feed inlets are K1 feed inlet, K2 feed inlet and K3 feed inlet, and the two discharge outlets are K4 low-boiling-point recovery outlet and K5 acetic acid outlet. The K1 feed port is used to introduce acetic anhydride and diketene, and the K1 feed port is correspondingly located on the side wall of distillation column 1 between the T1 decomposition and recombinant removal section and the T2 hydrolysis reaction and water separation section; The K2 feed inlet is used to introduce low-boiling substances, and the K2 feed inlet is correspondingly located on the side wall of distillation column 1 between the T2 hydrolysis reaction and water separation section and the T3 continued hydrolysis reaction and separation section; The K3 feed inlet is a water replenishment inlet, and the K3 feed inlet is located on the side wall of distillation column 1 between the T3 continued hydrolysis reaction separation section and the T4 low-boiling-point component separation section; The K4 low-boiling-point recovery outlet is located at the top of distillation column 1, and the K5 acetic acid outlet is located at the bottom of distillation column 1; The top condenser 2 is connected to the top of the distillation column 1; the bottom reboiler 3 is connected to the bottom of the distillation column 1.

[0022] Existing single-tower distillation methods cannot handle azeotropes and do not integrate the hydrolysis reaction, resulting in low separation efficiency. This invention embeds the hydrolysis reaction into the distillation process through a segmented design, utilizing the temperature gradient and material distribution in each separation section to achieve simultaneous reaction and separation. The multi-inlet stratified setup avoids backmixing, and the packing structure enhances mass transfer, enabling the components in the azeotrope to be separated step-by-step.

[0023] This invention achieves effective separation of azeotropic components such as isopropyl acetate and butanone from low-boiling-point substances, while simultaneously completely hydrolyzing acetic anhydride and diketene into recyclable acetic acid and acetone. The low-boiling-point substances recovered at the top of the column are free of moisture and can be directly used in subsequent purification processes; the acetic acid produced in the bottom of the column meets the purity requirements for reuse, significantly improving the overall material utilization rate and reducing waste emissions.

[0024] The low-boiling substances include acetic acid, isopropyl acetate, acetone, butanone, and water.

[0025] The T1 decomposition and recombination section, the T2 hydrolysis reaction and water separation section, the T3 continued hydrolysis reaction and separation section, and the T4 low-boiling-point component separation section are all equipped with packing structures or tray structures to enhance material contact.

[0026] The packing structure is any one or more combinations of corrugated packing structure, wire mesh packing structure or stepped ring packing structure, and the tray structure is a sieve tray tower, a floating valve, or other tray structure.

[0027] The function of section T1 is to remove the recombinant components and prevent acetic anhydride, acetic acid, diketene, and water from reaching the top of the column.

[0028] Section T2 serves as the hydrolysis and water separation section. Water, isopropyl acetate, methyl ethyl ketone, and acetone from the K2 inlet, due to their lower boiling points, rise under the influence of steam. Acetic anhydride and diketene from the upper section, due to their higher boiling points, descend. After contact with the packing material, acetic anhydride reacts with water to produce acetic acid, which flows to the bottom of the column, while diketene reacts with water to produce acetone and carbon dioxide, which flow to the top of the column.

[0029] The function of section T3 is to continue the hydrolysis reaction separation section. Since the water volume at inlet K2 is insufficient to provide the water volume required for the hydrolysis of acetic anhydride and diacetylacetone at inlet K1, and adding water at inlet K1 may lead to poor control, section T3 and water inlet K3 are set up to allow the incompletely hydrolyzed acetic anhydride and diacetylacetone to continue hydrolysis.

[0030] The T4 section is a low-boiling-point component separation section. Its function is to remove the acetone generated in the reaction and the added water, so that the acetic acid obtained in the final column bottom is free of water and acetone.

[0031] The final result is to obtain a low-boiling-point substance with almost no water content from the top of the column, which is then sent to another distillation column 1 for separation and purification, and acetic acid with almost no low-boiling-point substance is obtained from the bottom of the column.

[0032] After starting the reboiler 3 at the bottom of the column, the temperature inside the distillation column 1 is controlled to increase in a gradient from top to bottom along the height of the distillation column 1.

[0033] The vapor discharged from the top of distillation column 1 is condensed by the top condenser 2, and part of it is refluxed. The remaining vapor is then collected at the low-boiling-point outlet (K4). The top condenser is a device used to cool the gaseous low-boiling-point substances discharged from the top of the distillation column into a liquid state. It can be implemented using a shell-and-tube heat exchanger or a plate heat exchanger. Its function is to achieve gas-liquid separation through condensation phase change, facilitating the subsequent collection of low-boiling-point substances.

[0034] Compared to existing technologies, where low-boiling-point substances are difficult to separate due to azeotropic effects caused by water content, this invention removes water beforehand through a hydrolysis reaction within the distillation column, enabling efficient separation of low-boiling-point substances without azeotropic interference. Existing technologies do not treat the water in low-boiling-point substances, resulting in low recovery rates and insufficient purity due to azeotropy. This invention, through the combination of hydrolysis and a distillation column, significantly improves the recovery efficiency and purity of low-boiling-point substances.

[0035] Through the above technical solution, the present invention solves the problem of azeotropic separation caused by water content in low-boiling substances, ensuring that components such as isopropyl acetate and butanone in low-boiling substances can be efficiently recovered in an anhydrous state, while avoiding material waste and equipment corrosion caused by residual moisture in conventional distillation processes.

[0036] The packing or tray structure in the T1 decomposition and recombination section is used to prevent acetic anhydride, acetic acid, diketene, and water from moving to the top of distillation column 1. The packing or tray structure in the T2 hydrolysis reaction and water separation section, under the action of steam, causes the low-boiling-point substances such as isopropyl acetate, acetone, butanone, and water introduced through the K2 inlet to migrate to the top of the distillation column 1, and causes the high-boiling-point substances such as acetic anhydride and diketene introduced through the K1 inlet to move to the bottom of the distillation column 1. The hydrolysis reaction of acetic anhydride, diketene, and water is achieved through contact with the packing or tray structure. The packing or tray structure in the T3 hydrolysis reaction separation section, through the water added at the K3 inlet, allows the incompletely hydrolyzed acetic anhydride and diketene to continue hydrolysis under the contact action of the packing or tray structure. The packing or tray structure in the T4 low-boiling-point component separation section is used to remove acetone generated by the hydrolysis reaction and excess water added by the K3 feed inlet, ensuring that the acetic acid output from the bottom of the distillation column 1 is almost free of water and acetone.

[0037] At the bottom of section T4 (near the reboiler), the operating temperature is controlled slightly above the boiling point of acetic acid (usually maintained at around 119–123 °C, subject to deviation due to reboiler pressure), and in conjunction with the reflux control of the overhead condenser 2, the following separation effect is achieved: The material vapor rises in the bottom of the tower: At the bottom of section T4, due to the high temperature, materials such as acetic acid, acetone and some water will partially vaporize and move upward with the steam.

[0038] Acetone, butanone, and isopropyl acetate preferentially enter the top of the column, continuously enriching themselves in the gas phase during their ascent. They eventually enter the top condenser 2 with the steam, where some are refluxed after condensation and others are discharged through outlet K4.

[0039] Compared to existing technologies, traditional methods that directly hydrolyze acetic anhydride and diketene together result in incomplete reactions and difficulty in separating azeotropes, leading to material waste. This invention utilizes a segmented distillation column, controlling the flow of substances using a temperature gradient, and adding water in specific areas to promote the hydrolysis reaction, simultaneously achieving both reaction and separation. Compared to conventional single-stage hydrolysis processes, this multi-stage treatment improves reaction conversion and avoids the impact of azeotropic formation on the separation process.

[0040] This invention effectively solves the separation problem caused by the azeotropic reaction of methyl ethyl ketone (MEK), isopropyl acetate, and water in low-boiling-point substances, achieving efficient recovery of acetic acid from acetone, MEK, and isopropyl acetate. By controlling the reaction conditions in stages, the hydrolysis reaction is ensured to proceed completely, avoiding interference from unreacted materials in subsequent processes. The multi-stage separation design within the column allows each component to complete phase transition and mass transfer under optimal conditions, significantly improving the purity of recovered byproducts and process stability.

[0041] This invention employs a segmented distillation design, achieving multi-step separation and reaction through four functional sections (T1-T4) within the distillation column: Section T1: Removes heavy components (such as high-boiling-point byproducts) to prevent material from entering the top of the distillation column.

[0042] T2 segment: Acetic anhydride reacts with water to produce acetic acid (moving downwards), while diketene reacts with water to produce acetone and CO2 (moving upwards), achieving initial separation.

[0043] T3 stage: Water is added via K3 to ensure complete hydrolysis of unreacted acetic anhydride / diketene, thereby improving raw material utilization.

[0044] Section T4: Using the principle of distillation (difference in boiling points), low-boiling substances (acetone, water) are removed, and pure acetic acid is obtained in the bottom of the column.

[0045] Reaction-separation coupling: The hydrolysis reaction (acetic anhydride → acetic acid, diketene → acetone) is carried out simultaneously with the distillation process, and the reaction products are separated immediately, which shifts the reaction equilibrium to the right and increases the conversion rate.

[0046] Energy and materials integration: The top condenser recovers low-boiling-point substances (acetone, butanone, isopropyl acetate, etc.), the bottom reboiler circulates heat energy, and the hydrolysis reaction in the column releases heat, providing some heat and reducing energy consumption.

[0047] This invention features a segmented design to specifically remove heavy components (T1) and low-boiling substances (T4), resulting in high purity acetic acid in the bottom of the column, meeting industrial reuse standards.

[0048] The present invention has a high diketene hydrolysis rate and almost complete conversion of acetic anhydride, reducing raw material waste and lowering production costs.

[0049] This invention integrates the heat of reaction and the heat of distillation, thereby reducing the energy consumption of the reboiler.

[0050] This invention recovers byproducts such as acetone, butanone, and isopropyl acetate using K4, reducing waste liquid volume and meeting the requirements of green chemical industry.

[0051] The above description is merely an embodiment of the present invention and is not intended to limit the scope of protection of the present invention. For those skilled in the art, the present invention can have various modifications and variations. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of the present invention should be included within the scope of protection of the present invention.

Claims

1. A by-product recovery system in an acetylacetone production process, characterized by, The rectifying tower, the overhead condenser and the bottom reboiler are included. The rectifying tower is divided into four separation sections from top to bottom along the height direction, which are T1 heavy component removal section, T2 hydrolysis reaction and water separation section, T3 continuous hydrolysis reaction separation section and T4 low boiling point component separation section. Three feeding inlets and two discharging outlets are arranged on the rectifying tower, which are K1 feeding inlet, K2 feeding inlet, K3 feeding inlet and K4 low boiling point component recovery outlet and K5 acetic acid outlet. The K1 feeding inlet is used for feeding acetic anhydride and divinyl ketone, and the K1 feeding inlet is arranged on the side wall of the rectifying tower between T1 heavy component removal section and T2 hydrolysis reaction and water separation section. The K2 feeding inlet is used for feeding low boiling point component, and the K2 feeding inlet is arranged on the side wall of the rectifying tower between T2 hydrolysis reaction and water separation section and T3 continuous hydrolysis reaction separation section. The K3 feeding inlet is a water feeding inlet, and the K3 feeding inlet is arranged on the side wall of the rectifying tower between T3 continuous hydrolysis reaction separation section and T4 low boiling point component separation section. The K4 low boiling point component recovery outlet is arranged at the top of the rectifying tower, and the K5 acetic acid outlet is arranged at the bottom of the rectifying tower. The overhead condenser is connected with the top of the rectifying tower, and the bottom reboiler is connected with the bottom of the rectifying tower.

2. The system for recovering by-products in a process for producing acetylacetone according to claim 1, characterized in that: The low boiling point component includes acetic acid, isopropenyl acetate, acetone, butanone and water.

3. The system for recovering by-products in a process for producing acetylacetone according to claim 1, characterized in that: The T1 heavy component removal section, the T2 hydrolysis reaction and water separation section, the T3 continuous hydrolysis reaction separation section and the T4 low boiling point component separation section are all provided with a packing structure or a tray structure for enhancing the contact effect of materials.

4. The system for recovering by-products in a process for producing acetylacetone according to claim 3, characterized in that: The packing structure is any one or a combination of corrugated packing structure, wire mesh packing structure or stepped ring packing structure, and the tray structure is sieve tray column or float valve column.

5. A method for recovering by-products in an acetylacetone production process, characterized by, The method comprises the following steps: (1) feeding acetic anhydride and divinyl ketone into the rectifying tower through the K1 feeding inlet, feeding low boiling point component into the rectifying tower through the K2 feeding inlet, and starting the bottom reboiler and the overhead condenser; (2) in the T1 heavy component removal section, the acetic anhydride and divinyl ketone fed through the K1 feeding inlet are subjected to heavy component removal treatment to prevent the materials from entering the top region of the tower; (3) in the low boiling point component fed through the K2 feeding inlet, water, isopropenyl acetate, butanone and acetone move upward under the action of steam, and the acetic anhydride and divinyl ketone fed through the K1 feeding inlet move downward due to the higher boiling point, and after the two are contacted, the acetic anhydride reacts with water to generate acetic acid and moves to the lower part of the rectifying tower, and the divinyl ketone reacts with water to generate acetone and carbon dioxide and moves to the upper part of the rectifying tower; (4) the materials enter the T3 continuous hydrolysis reaction separation section, water is supplemented through the K3 feeding inlet, and the acetic anhydride and divinyl ketone that are not completely hydrolyzed continue to undergo hydrolysis reaction with water; (5) the materials enter the T4 low boiling point component separation section, the acetone generated in the T3 continuous hydrolysis reaction separation section and the supplemented water are removed, and it is ensured that the acetic acid obtained from the tower kettle of the rectifying tower almost does not contain water and acetone. (6) The low-boiling-point material discharged from the top of the rectifying column is collected by the K4 recovery low-boiling-point material outlet and sent to the next stage for separation and purification; the acetic acid discharged from the bottom of the rectifying column is collected by the K5 acetic acid outlet.

6. The method according to claim 5, wherein the acetylacetone production process is a process according to any one of claims 1 to 4. After the bottom reboiler is started in step (1), the temperature in the rectifying column is controlled to increase along the height of the rectifying column from top to bottom.

7. The method according to claim 5, wherein the method is characterized by, In step (6), the steam discharged from the top of the rectifying column is condensed by the top condenser, part of which is refluxed, and the low-boiling-point material is collected by the K4 recovery low-boiling-point material outlet.

8. The method according to claim 5, wherein, The T1 heavy component removal section is filled with packing to prevent acetic anhydride, acetic acid, divinyl ketone, and water from moving to the top of the rectifying column; The T2 hydrolysis and water separation section is filled with packing, which, under the action of steam, causes the acetic acid, isopropenyl acetate, acetone, butanone, and water in the low-boiling-point material introduced through the K2 inlet to migrate to the top of the rectifying column, and the acetic anhydride and divinyl ketone introduced through the K1 inlet to move to the bottom of the rectifying column, and the hydrolysis of acetic anhydride and divinyl ketone with water is achieved through the packing or tray structure; The T3 continued hydrolysis and separation section is filled with packing or tray structure, which, under the action of the water introduced through the K3 inlet, causes the acetic anhydride and divinyl ketone that have not been completely hydrolyzed to continue the hydrolysis reaction under the action of the packing or tray structure; The T4 low-boiling-point component separation section is filled with packing or tray structure, which is used to remove the acetone generated by the hydrolysis reaction and the excess water introduced through the K3 inlet, and to ensure that the acetic acid output from the bottom of the rectifying column contains almost no water and acetone.

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