An apparatus and method for distillative extraction of azelaic acid

Abstract

The application relates to an azelaic acid preparation technical field, in particular to a distillation and extraction device and method for azelaic acid. The device comprises a distillation kettle and an extraction body. In the application, when the motor drives the fan to rotate, the top ring is synchronously driven to rotate, the cross support is driven by the top ring, and the pressure disc is driven to reciprocate up and down in the pressure groove. When the pressure disc moves downward in the pressure groove, the liquid in the pressure groove is extruded downward by the pressure disc through the connecting hole to form an elongated fluid and enter the refining groove. When the fluid passes through the cutting drop cylinder, the fluid is cut into drops by the cutting piece of the cutting drop cylinder, the contact area of the water vapor and the liquid is increased, azelaic aldehyde in the liquid forms azeotrope or immiscible mixture with the water vapor, so that the azelaic aldehyde in the liquid is separated and extracted, the residual liquid after the separation of the azelaic aldehyde is collected by the collecting cavity and discharged downward through the discharge pipe, and the residual liquid with high azelaic acid precursor content is obtained.

Description

Technical Field

[0001] This invention relates to the field of azelaic acid preparation technology, and more specifically, to a distillation extraction apparatus and method for azelaic acid. Background Technology

[0002] Azelaic acid is an important organic synthesis intermediate used in the synthesis of azelaic acid ester plasticizers. It can also be used to synthesize fragrances, lubricants, oils and polyamide resins. High-purity azelaic acid also has important applications in electrolysis, capacitors and aerospace. Furthermore, other alkyl esters of azelaic acid can be used as lubricants, exhibiting excellent viscosity, temperature characteristics and good addition sensitivity.

[0003] The main industrial production route for azelaic acid is through the cracking and oxidation of oleic acid. The cracking products include nonanal and azelaic acid precursors. Nonanal is a volatile component that can be separated from the reaction mixture by steam distillation or vacuum distillation. Therefore, nonanal can be removed from the cracking products by extraction using a distillation apparatus, leaving the remaining cracking products, namely the azelaic acid precursor.

[0004] Existing steam distillation apparatuses, such as CN114272633B, involve an acidic water stripping device, including a stripping tower body. A top cover is installed on the top of the stripping tower body. An exhaust pipe is fixed to one side of the top of the stripping tower body. A liquid inlet mechanism is installed on the top cover. An air inlet mechanism is inserted into the bottom of the stripping tower body. A drain pipe is installed on one side of the bottom of the stripping tower body. An installation port is opened on one side of the installation port. An extension frame is installed on one side of the extension frame, and fixing rings are provided on both sides of the extension frame to be fixedly connected to the stripping tower body. A shelf is installed inside the extension frame. The shelf has a gas guide cavity adapted to the inner diameter of the stripping tower body. Two liquid guide plates are installed inside the gas guide cavity.

[0005] When the above-mentioned stripping device is applied to the distillation extraction of pyrolysis products, the pyrolysis products are viscous liquids with poor flowability. The water vapor used in the above-mentioned device can only contact the surface liquid through bubbling. The deep nonanal in the pyrolysis products cannot effectively diffuse to the gas-liquid interface, resulting in unsatisfactory distillation extraction efficiency of nonanal. As a result, the remaining part of the pyrolysis products still contains a large amount of nonanal, making it difficult to collect high-purity azelaic acid precursor. Summary of the Invention

[0006] The purpose of this invention is to avoid the problem that the distillation extraction efficiency of nonanal in the cracking products is low due to water vapor only being able to contact the liquid surface, resulting in low purity of the final recovered azelaic acid precursor.

[0007] The purpose of this invention is to provide a distillation extraction apparatus and method for azelaic acid. By using water vapor to contact droplets, the water vapor and the pyrolysis products can be fully contacted, thereby improving the distillation extraction efficiency of nonanal, reducing the nonanal content in the pyrolysis products, and ultimately obtaining a high-purity azelaic acid precursor.

[0008] To achieve the above objectives, one objective of the present invention is to provide a distillation and extraction apparatus for azelaic acid, comprising a distillation vessel and an extractant disposed within the distillation vessel;

[0009] The distillation vessel includes a main body and connecting pipes symmetrically arranged on both sides of the main body. The main body has a liquid storage chamber and a stripping chamber. The bottom end of the liquid storage chamber is connected to the stripping chamber, and the two ends of the stripping chamber are connected to the connecting pipes respectively.

[0010] The extractor includes a pumping structure, a supply and discharge structure, and a drop-forming structure. The supply and discharge structure is connected to the connecting pipe for inputting / receiving water vapor. The pumping structure is used to drive water vapor to flow along the stripping chamber. The drop-forming structure is located in the liquid storage chamber for converting liquid into droplets. The pumping structure and the drop-forming structure are connected by a drive.

[0011] When the pump structure drives the water vapor flow, it simultaneously drives the droplet-forming structure, which in turn squeezes the pyrolysis products in the liquid storage chamber, converting the liquid into droplets through compression.

[0012] As a further improvement to this technical solution, a central island is provided in the middle of the connecting pipe. The air pumping structure includes a motor and fans symmetrically arranged on both sides of the central island. The motor is located at the bottom of the main body and is driven by a first gear set. The first gear set is driven by a second gear set, and the second gear set is driven by the fans.

[0013] The fan is driven by a motor through the first gear set and the second gear set, which enables the fan to drive water vapor to move along the stripping chamber.

[0014] As a further improvement to this technical solution, the drop-forming structure includes an extrusion member and a drop-cutting member disposed at the bottom of the extrusion member. The extrusion member is disposed in the liquid storage chamber and is connected to the first gear set for transmission. The first gear set drives the extrusion member to rotate, so that the extrusion member compresses and extrudes the liquid in the liquid storage chamber. When the extrusion member rotates, it synchronously drives the drop-cutting member to rotate, so that the drop-cutting member cuts the extruded liquid to form droplets.

[0015] Furthermore, the extrusion component includes a top ring and an extrusion assembly located at the bottom of the top ring. The top ring is rotatably connected to the inner wall of the main body at the top of the liquid storage chamber. The first gear set meshes with the top ring. A central shaft is provided at the bottom center of the top ring. The extrusion assembly includes a cross bracket and a pressure plate. The central shaft is connected to the cross bracket by a lead screw. The end of the cross bracket is slidably connected to the inner wall of the liquid storage chamber. The bottom of the liquid storage chamber is separated by a partition to form a pressure groove and a refining groove with two cylindrical grooves. Multiple connecting holes are provided on the partition. The pressure plate is located in the pressure groove. The top of the pressure plate is connected to the bottom of the cross bracket by a connecting rod.

[0016] When the motor drives the fan to rotate, the motor drives the top ring to rotate synchronously through the first gear set. This causes the top ring to drive the cross bracket to move up and down along the liquid storage chamber through the central shaft. When the pressure plate moves down in the pressure tank, the liquid in the pressure tank is squeezed down by the pressure plate and forms a thin fluid through the connecting hole and enters the refining tank.

[0017] Furthermore, the pressure plate has an opening that extends through the upper and lower surfaces. A movable baffle is located at the bottom of the opening, and a limit rod is located at the top of the movable baffle. The limit rod engages with the bottom of the pressure plate. When the pressure plate moves down in the pressure groove to squeeze the liquid, the movable baffle blocks the opening, preventing the liquid below the pressure plate from flowing through the opening to the top of the pressure plate. When the pressure plate moves up, the liquid above the pressure plate pushes the movable baffle down.

[0018] As a further improvement to this technical solution, the dripping component includes a dripping cylinder whose outer wall is rotatably connected to the inner wall of the refining tank. A snap-fit ​​rod is provided at the bottom of the central shaft, and the snap-fit ​​rod is snap-fitted with the dripping cylinder. Multiple downwardly inclined slices are arranged in multiple layers inside the dripping cylinder. A collection chamber for collecting residual liquid is opened in the body below the refining tank. A discharge pipe communicating with the collection chamber is provided on the outside of the body.

[0019] When fluid passes through the dropper, the dropper blades cut the fluid into droplets.

[0020] As a further improvement to this technical solution, a dispersing component is also installed at the bottom of the snap-fit ​​rod. The dispersing component is used to impact the droplet, causing the droplet surface to expand, thereby further increasing the contact area with water vapor.

[0021] As a further improvement to this technical solution, the stripping chamber is a channel with a "U" shaped cross-section, and the dispersing component is located at the bottom of the stripping chamber. After the water vapor enters through the connecting pipe at one end of the main body, it is driven by the fan into the stripping chamber and comes into contact with the droplets that expand on the surface after being impacted by the dispersing component. The impacted droplets are blocked and cannot enter the connecting pipe.

[0022] As a further improvement to this technical solution, a guide block is provided in the collection chamber below the dispersing component to guide the gas to flow along the stripping chamber, and water vapor can flow back into the stripping chamber along the inclined surface of the guide block.

[0023] In this invention, the pump structure drives the water vapor flow and simultaneously drives the droplet-forming structure, which in turn compresses the pyrolysis products in the liquid storage chamber. By compressing the liquid, the liquid is converted into droplets, thereby increasing the contact area of ​​the water vapor, improving the extraction efficiency of nonanal, reducing the nonanal content, and increasing the purity of the azelaic acid precursor.

[0024] The second objective of this invention is to provide a method for distillation extraction using the aforementioned azelaic acid distillation extraction apparatus, comprising the following steps:

[0025] Step S1: Acidify the oleic acid cracking products to a strong acidic state using a strong acid, then wash the acidified mixture with water or perform liquid-liquid separation, and then perform dehydration and drying to obtain an oily liquid or a liquid with low to medium viscosity.

[0026] Step S2: Inject the liquid into the storage chamber, and input water vapor into the connecting pipe at one end of the main body through the supply and discharge structure. Then, the motor drives the fan to rotate, thereby driving the water vapor to move along the stripping chamber.

[0027] Step S3: When the motor drives the fan to rotate, the motor synchronously drives the top ring to rotate. The top ring drives the pressure plate to move up and down in the pressure groove. When the pressure plate moves down in the pressure groove, the liquid in the pressure groove is squeezed down by the pressure plate and forms a thin fluid through the connecting hole and enters the refining groove.

[0028] Step S4: When the fluid passes through the dropper, the dropper blades cut the fluid into droplets. Nonaldehyde and water vapor form an azeotrope or an immiscible mixture, thereby extracting and separating the nonaldehyde from the liquid. Then, it is discharged from the connecting pipe at the other end of the main body along the direction of water vapor flow.

[0029] Step S5: The residual liquid after the separation of nonanal is collected by the collection chamber and discharged downward through the discharge pipe to obtain the azelaic acid precursor residual liquid.

[0030] Compared with the prior art, the beneficial effects of the present invention are as follows:

[0031] 1. In the distillation extraction apparatus and method for azelaic acid, when the motor drives the fan to rotate, it synchronously drives the top ring to rotate, which in turn drives the cross support, which in turn drives the pressure plate to move up and down in the pressure tank. When the pressure plate moves down in the pressure tank, the liquid in the pressure tank is squeezed down by the pressure plate and forms a thin fluid through the connecting hole and enters the refining tank. When the fluid passes through the dropper, the slice of the dropper cuts the fluid to form droplets, which increases the contact area between water vapor and liquid, so that nonanal in the liquid forms an azeotrope or an immiscible mixture with water vapor, thereby extracting and separating nonanal from the liquid. The residual liquid after the separation of nonanal is collected by the collection chamber and discharged downward through the discharge pipe, thereby obtaining a residual liquid with a high content of azelaic acid precursor.

[0032] 2. In the distillation extraction apparatus and method for azelaic acid, the movable baffle achieves limited vertical displacement through a locking limit rod. When the pressure plate moves downward in the pressure tank to squeeze the liquid, the movable baffle blocks the opening of the pressure plate, preventing the liquid below the pressure plate from flowing to the top of the pressure plate. When the pressure plate moves upward, the liquid above the pressure plate pushes the movable baffle downward, allowing the liquid to flow to the bottom of the pressure plate through the opening. This ensures that when the pressure plate reaches the upper stop point and begins to move downward, there is sufficient liquid in the pressure tank, thereby ensuring the continuous pressure of the pressure plate on the liquid. Attached Figure Description

[0033] Figure 1 This is a schematic diagram of the overall structure of the present invention;

[0034] Figure 2 This is a schematic diagram of the overall cross-sectional structure of the present invention;

[0035] Figure 3 This is a schematic diagram of the cross-sectional structure of the main body of the present invention;

[0036] Figure 4 This is a schematic cross-sectional view of the structure and fit between the distillation vessel and the extractor body of the present invention;

[0037] Figure 5 This is a schematic cross-sectional view of the structure in which the second gear set inside the connecting pipe of the present invention engages with the fan;

[0038] Figure 6 This is a schematic cross-sectional view of the body and droplet-forming structure of the present invention.

[0039] Figure 7 This is a schematic diagram of the extrusion part of the present invention;

[0040] Figure 8 This is a schematic diagram showing the structural cooperation between the liquid storage chamber and the stripping chamber of the present invention;

[0041] Figure 9 This is a schematic diagram showing the structural fit between the central shaft, the drip-cutting component, and the dispersing component of the present invention;

[0042] Figure 10 This is a schematic diagram of the structure of the extractant inside the distillation vessel of the present invention.

[0043] The meanings of the labels in the diagram are as follows:

[0044] 1. Distillation vessel; 11. Body; 111. Liquid storage chamber; 1111. Pressure tank; 1112. Refining tank; 1113. Connecting hole; 112. Stripping chamber; 113. Collection chamber; 1131. Guide block; 12. Connecting pipe; 121. Central island; 13. Discharge pipe;

[0045] 2. Extraction body; 21. Motor; 22. First gear set; 23. Second gear set; 24. Fan; 25. Drop formation structure; 251. Top ring; 252. Central shaft; 2521. Clamping rod; 253. Extrusion assembly; 2531. Cross support; 2532. Connecting rod; 2533. Pressure plate; 2534. Pan opening; 2535. Movable baffle; 2536. Limiting rod; 254. Dropper cylinder; 2541. Slice; 255. Dispersing component. Detailed Implementation

[0046] The technical solutions in the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0047] In the description of this invention, it should be understood that the terms "center," "longitudinal," "lateral," "length," "width," "thickness," "upper," "lower," "front," "rear," "left," "right," "vertical," "horizontal," "top," "bottom," "inner," "outer," "clockwise," and "counterclockwise," etc., indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings. They are only for the convenience of describing this invention and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation. Therefore, they should not be construed as limitations on this invention.

[0048] Furthermore, the terms "first" and "second" are used for descriptive purposes only and should not be construed as indicating or implying relative importance or implicitly specifying the number of technical features indicated. Thus, a feature defined as "first" or "second" may explicitly or implicitly include one or more of that feature. In the description of this invention, "a plurality of" means two or more, unless otherwise explicitly specified.

[0049] Please see Figure 1 , Figure 2 , Figure 3 , Figure 4 As shown, one of the objectives of this embodiment is to provide a distillation and extraction apparatus for azelaic acid, including a distillation vessel 1 and an extractant 2 disposed within the distillation vessel 1;

[0050] The distillation vessel 1 includes a body 11 and connecting pipes 12 symmetrically arranged on both sides of the body 11. The body 11 has a liquid storage chamber 111 and a stripping chamber 112. The bottom end of the liquid storage chamber 111 is connected to the stripping chamber 112, and the two ends of the stripping chamber 112 are respectively connected to the connecting pipes 12.

[0051] The extractor 2 includes a pumping structure, a supply and discharge structure, and a drop-forming structure 25. The supply and discharge structure (not shown in the figure) is connected to the connecting pipe 12 for inputting / receiving water vapor. The pumping structure is used to drive water vapor to flow along the stripping chamber 112. The drop-forming structure 25 is located in the liquid storage chamber 111 for converting liquid into droplets. The pumping structure is connected to the drop-forming structure 25 in a drive connection.

[0052] Liquid (formed from oleic acid cracking products after pretreatment) is injected into the storage chamber 111. Then, water vapor is introduced into the connecting pipe 12 at one end of the main body 11 by the supply and discharge structure. The pump structure drives the water vapor to flow along the stripping chamber 112 until it is discharged from the connecting pipe 12 at the other end of the main body 11. When the pump structure drives the water vapor to flow, it simultaneously drives the droplet-forming structure 25, so that the droplet-forming structure 25 squeezes the cracking products in the storage chamber 111. The liquid is converted into droplets by compression, thereby increasing the contact area of ​​water vapor, improving the extraction efficiency of nonanal, reducing the nonanal content, and improving the purity of the azelaic acid precursor.

[0053] The above structure is disclosed below:

[0054] After steam is introduced into the supply and discharge structure through the connecting pipe 12 at one end of the main body 11, in order to facilitate the movement of steam in the stripping chamber 112 and control the flow rate of steam in the stripping chamber 112, such as... Figure 4 , Figure 5 As shown, a central island 121 is provided in the middle of the connecting pipe 12. The air pumping structure includes a motor 21 and fans 24 symmetrically arranged on both sides of the central island 121 in the connecting pipe 12. The motor 21 is located at the bottom of the main body 11. The motor 21 is driven by a first gear set 22. The first gear set 22 is driven by a second gear set 23. The second gear set 23 is driven by the fan 24.

[0055] Specifically, the first gear set 22 includes a first transmission rod and a second transmission rod meshing with one end of the first transmission rod. The other end of the first transmission rod meshes with the output shaft of the motor 21. The second gear set 23 includes an inner tube support and a third transmission rod located on the inner tube support. The fan 24 is rotatably connected to the inner tube support. One end of the third transmission rod meshes with the second transmission rod, and the other end of the third transmission rod meshes with the fan 24. The motor 21 drives the fan 24 to rotate through the first gear set 22 and the second gear set 23, so that the fan 24 can drive water vapor to move along the steam stripping chamber 112. Furthermore, by changing the rotation speed of the fan 24, the water vapor flow rate can be adjusted.

[0056] After setting the steam flow rate, the liquid needs to be brought into contact with the steam to facilitate the extraction of nonanal from the liquid (nonanal forms an azeotrope or immiscible mixture with steam and is carried out at temperatures below 100°C). However, due to the viscosity and poor fluidity of the liquid, the deeper nonanal is difficult to diffuse effectively to the gas-liquid interface. To address this, the liquid can be converted into droplets to increase the contact area with the steam, thereby improving the extraction efficiency of nonanal by the steam. To achieve this, as... Figure 6 , Figure 8 As shown, the droplet-forming structure 25 includes an extrusion member and a droplet-cutting member disposed at the bottom of the extrusion member. The extrusion member is disposed in the liquid storage chamber 111 and is connected to the first gear set 22 for transmission. The first gear set 22 drives the extrusion member to rotate, so that the extrusion member compresses and extrudes the liquid in the liquid storage chamber 111. When the extrusion member rotates, it synchronously drives the droplet-cutting member to rotate, so that the droplet-cutting member cuts the extruded liquid to form droplets.

[0057] The structure of the extrusion part and the dripping part described above will be disclosed in detail below:

[0058] like Figure 6 , Figure 7 , Figure 8As shown, the extrusion component includes a top ring 251 and a pressing assembly 253 located at the bottom of the top ring 251. The top ring 251 is rotatably connected to the inner wall of the body 11 at the top of the liquid storage chamber 111. The top ring 251 has several teeth on its outer periphery. The top of the second transmission rod of the first gear set 22 is provided with a gear. The first gear set 22 meshes with the top ring 251 through the provided gears and teeth. A central shaft 252 is provided in the middle of the bottom of the top ring 251. The pressing assembly 253 includes a cross bracket 2531 and a pressure plate 2533. One end of the bottom of the central shaft 252 passes through... The middle part of the cross bracket 2531 is connected to the lead screw of the cross bracket 2531, and the end of the cross bracket 2531 is slidably connected to the inner wall of the liquid storage chamber 111. The bottom of the liquid storage chamber 111 is separated by a partition to form a pressure groove 1111 and a refining groove 1112 with two cylindrical structures. The partition has multiple connecting holes 1113. The pressure plate 2533 matches the pressure groove 1111 and is located in the pressure groove 1111. The top of the pressure plate 2533 is connected to the bottom of the cross bracket 2531 through a connecting rod 2532.

[0059] When motor 21 drives fan 24 to rotate, motor 21 synchronously drives top ring 251 to rotate via first gear set 22. This causes top ring 251 to drive cross bracket 2531 to reciprocate up and down along liquid storage chamber 111 via central shaft 252, thus driving pressure plate 2533 to reciprocate up and down within pressure groove 1111. Figure 10 As shown by the middle arrow a, when the pressure plate 2533 moves down in the pressure tank 1111, the liquid in the pressure tank 1111 is squeezed downward by the pressure plate 2533 and passes through the connecting hole 1113 to form a thin fluid and enter the refining tank 1112.

[0060] Furthermore, to ensure a continuous pressure effect on the liquid, the pressure plate 2533 has an opening 2534 extending through both the upper and lower surfaces. A movable baffle 2535 is located at the bottom of the opening 2534, and a limiting rod 2536 is located at the top of the movable baffle 2535. The limiting rod 2536 engages with the bottom of the pressure plate 2533, allowing the movable baffle 2535 to move vertically to a limited extent via the engaging limiting rod 2536. When the pressure plate 2533 moves downward within the pressure groove 1111 to compress the liquid... The movable baffle 2535 blocks the opening 2534, preventing the liquid below the pressure plate 2533 from flowing through the opening 2534 to the top of the pressure plate 2533. When the pressure plate 2533 moves upward, the liquid above the pressure plate 2533 pushes the movable baffle 2535 downward, allowing the liquid to flow through the opening 2534 to the bottom of the pressure plate 2533. This ensures that when the pressure plate 2533 reaches the upper stop point and begins to move downward, there is sufficient liquid in the pressure groove 1111, thus ensuring the continuous pressure of the pressure plate 2533 on the liquid.

[0061] When the liquid passes through the connecting hole 1113 to form a narrow fluid and enters the refining tank 1112, as... Figure 8 , Figure 9 As shown, the dripping component includes a dripping cylinder 254 whose outer wall is rotatably connected to the inner wall of the refining tank 1112. A locking rod 2521 is provided at the bottom of the central shaft 252. The bottom end of the locking rod 2521 passes through the middle of the dripping cylinder 254 and engages with the dripping cylinder 254. Multiple downwardly inclined slices 2541 are arranged in multiple layers inside the dripping cylinder 254. A collection chamber 113 for collecting residual liquid is opened inside the body 11 below the refining tank 1112. A discharge pipe 13 communicating with the collection chamber 113 is provided outside the body 11.

[0062] When the top ring 251 rotates, it synchronously drives the cutting tube 254 to rotate in the refining tank 1112 via the central shaft 252. The liquid forms a thin fluid through the connecting hole 1113 and falls downward into the refining tank 1112. When the fluid passes through the cutting tube 254, the slice 2541 of the cutting tube 254 cuts the fluid into droplets, increasing the contact area between water vapor and liquid. This causes nonanal in the liquid to form an azeotrope or an immiscible mixture with water vapor, thereby extracting and separating nonanal from the liquid. The nonanal is then discharged from the connecting tube 12 at the other end of the body 11 along the direction of water vapor flow. The residual liquid after the nonanal is separated is collected by the collection chamber 113 and discharged downward through the discharge pipe 13, thus obtaining a residual liquid with a high content of azelaic acid precursor.

[0063] In order to further improve the extraction efficiency of nonanal, a dispersing component 255 is also installed at the bottom of the clamping rod 2521. The dispersing component 255 is used to impact the droplets, causing the droplet surface to expand, thereby further increasing the contact area with water vapor, which can further improve the extraction efficiency of nonanal and is conducive to obtaining high-purity azelaic acid precursor.

[0064] To facilitate the collection of residual azelaic acid precursor solution and to prevent droplets impacted by the dispersing component 255 from entering the connecting pipe 12 and causing unnecessary losses, the stripping chamber 112 is a channel with a "U" shaped cross-section, and the dispersing component 255 is located at the bottom of the stripping chamber 112. Figure 10As shown, water vapor enters through the connecting pipe 12 at one end of the main body 11 and is driven into the stripping chamber 112 by the fan 24. It then contacts the droplets that have expanded on the surface after being impacted by the abrasive component 255, separating the nonanal from the droplets. The vapor then exits through the connecting pipe 12 at the other end of the main body 11 along the stripping chamber 112. Due to the "U"-shaped groove structure of the stripping chamber 112, the impacted droplets are blocked from entering the connecting pipe 12, thus avoiding unnecessary losses and facilitating the removal of residual azelaic acid precursor liquid. In order to prevent water vapor from flowing out of the stripping chamber 112 and the connecting pipe 12, a guide block 1131 is provided in the collection chamber 113 below the dispersing component 255 to guide the gas to flow along the stripping chamber 112. With the guide block 1131 provided, when water vapor flows along the stripping chamber 112 to the collection chamber 113, the water vapor can flow back into the stripping chamber 112 along the inclined surface of the guide block 1131, thereby preventing water vapor from being discharged from the discharge pipe 13.

[0065] The second objective of this embodiment is to provide a method for distillation extraction using the aforementioned azelaic acid distillation extraction apparatus, the specific steps of which are as follows:

[0066] Step S1: Acidify the oleic acid cracking products to a strong acid pH < 2 using strong acids such as sulfuric acid or hydrochloric acid. Then wash the acidified mixture with water or perform liquid-liquid separation. If organic solvent extraction is used, remove water-soluble inorganic salts and some water-soluble impurities. Then dehydrate and dry to obtain an oily liquid or a low to medium viscosity liquid.

[0067] Step S2: Inject liquid into the storage chamber 111, and input water vapor into the connecting pipe 12 at one end of the body 11 by the supply and discharge structure. Then, the motor 21 drives the fan 24 to rotate, thereby driving the water vapor to move along the stripping chamber 112.

[0068] Step S3: When the motor 21 drives the fan 24 to rotate, the motor 21 synchronously drives the top ring 251 to rotate. The top ring 251 drives the pressure plate 2533 to move up and down in the pressure groove 1111. When the pressure plate 2533 moves down in the pressure groove 1111, the liquid in the pressure groove 1111 is squeezed down by the pressure plate 2533 and passes through the connecting hole 1113 to form a thin fluid and enter the refining groove 1112.

[0069] Step S4: When the fluid passes through the dropper 254, the dropper 254 is cut into droplets by the slice 2541 of the dropper 254. Nonaldehyde and water vapor form an azeotrope or an immiscible mixture, thereby extracting and separating the nonaldehyde in the liquid, and then discharging it from the connecting pipe 12 at the other end of the body 11 along the direction of water vapor flow.

[0070] Step S5: The residual liquid after the separation of nonanal is collected by the collection chamber 113 and discharged downward through the discharge pipe 13, thereby obtaining the azelaic acid precursor residual liquid.

[0071] The foregoing has shown and described the basic principles, main features, and advantages of the present invention. Those skilled in the art should understand that the present invention is not limited to the above embodiments. The embodiments and descriptions in the specification are merely preferred examples and are not intended to limit the invention. Various changes and modifications can be made to the invention without departing from its spirit and scope, and all such changes and modifications fall within the scope of the present invention as claimed. The scope of protection of the present invention is defined by the appended claims and their equivalents.

Claims

1. A distillation extraction apparatus for azelaic acid, comprising a distillation vessel (1) and an extractant (2) disposed within the distillation vessel (1), characterized in that: The distillation vessel (1) includes a body (11) and connecting pipes (12) symmetrically arranged on both sides of the body (11). The body (11) has a liquid storage chamber (111) and a stripping chamber (112). The bottom end of the liquid storage chamber (111) is connected to the stripping chamber (112), and the two ends of the stripping chamber (112) are connected to the connecting pipes (12) respectively. The extractor (2) includes a pumping structure, a supply and discharge structure and a drop-forming structure (25). The supply and discharge structure is connected to the connecting pipe (12) for inputting / receiving water vapor. The pumping structure is used to drive water vapor to flow along the stripping chamber (112). The drop-forming structure (25) is located in the liquid storage chamber (111) for converting liquid into droplets. The pumping structure and the drop-forming structure (25) are connected by a drive. When the pump structure drives the water vapor flow, it simultaneously drives the droplet-forming structure (25), which causes the droplet-forming structure (25) to squeeze the cracking products in the liquid storage chamber (111) and convert the liquid into droplets through compression. A central island (121) is provided in the middle of the connecting pipe (12). The pump structure includes a motor (21) and fans (24) symmetrically arranged on both sides of the central island (121). The motor (21) is located at the bottom of the main body (11). The motor (21) is driven by a first gear set (22). The first gear set (22) is driven by a second gear set (23). The second gear set (23) is driven by the fan (24). The droplet-forming structure (25) includes an extrusion member and a drop-cutting member disposed at the bottom of the extrusion member. The extrusion member is disposed in the liquid storage chamber (111) and is connected to the first gear set (22) for transmission. The first gear set (22) drives the extrusion member to rotate, so that the extrusion member compresses and extrudes the liquid in the liquid storage chamber (111). When the extrusion member rotates, it drives the drop-cutting member to rotate synchronously, so that the drop-cutting member cuts the extruded liquid to form droplets. The extrusion assembly includes a top ring (251) and an extrusion assembly (253) located at the bottom of the top ring (251). The top ring (251) is located at the top of the liquid storage chamber (111) and is rotatably connected to the inner wall of the body (11). The first gear set (22) meshes with the top ring (251). A central shaft (252) is provided at the bottom center of the top ring (251). The extrusion assembly (253) includes a cross bracket (2531) and a pressure plate (2533). The central shaft (252) and the cross bracket (2531) are connected. The screw is connected to the end of the cross bracket (2531) and slides up and down to the inner wall of the liquid storage chamber (111). The bottom of the liquid storage chamber (111) is separated by a partition to form a pressure groove (1111) and a refining groove (1112) with two cylindrical grooves. Multiple connecting holes (1113) are provided on the partition. The pressure plate (2533) is located in the pressure groove (1111). The top of the pressure plate (2533) is connected to the bottom of the cross bracket (2531) through a connecting rod (2532). The pressure plate (2533) has a through opening (2534) on its surface that extends through the upper and lower surfaces. A movable baffle (2535) is provided at the bottom of the opening (2534). A limit rod (2536) is provided at the top of the movable baffle (2535). The limit rod (2536) is engaged with the bottom of the pressure plate (2533). The dripping component includes a dripping cylinder (254) whose outer wall is rotatably connected to the inner wall of the refining tank (1112). A snap-fit ​​rod (2521) is provided at the bottom of the central shaft (252). The snap-fit ​​rod (2521) is snapped into the dripping cylinder (254). Multiple downwardly inclined slices (2541) are arranged in multiple layers inside the dripping cylinder (254). A collection chamber (113) for collecting residual liquid is opened in the body (11) below the refining tank (1112). A discharge pipe (13) communicating with the collection chamber (113) is provided outside the body (11). The bottom end of the snap rod (2521) is also equipped with a dispersing component (255), which is used to impact the droplet and expand the surface of the droplet; The stripping chamber (112) is a channel with a "U" shaped cross-section, and the disintegrating component (255) is located at the bottom of the stripping chamber (112).

2. The distillation and extraction apparatus for azelaic acid according to claim 1, characterized in that: Inside the collection chamber (113), below the dispersing component (255), there is a guide block (1131) for guiding the gas to flow along the stripping chamber (112).

3. A method for distillation extraction using a distillation extraction apparatus for azelaic acid as described in any one of claims 1-2, characterized in that, Includes the following steps: Step S1: Acidify the oleic acid cracking products to a strong acidic state using a strong acid, then wash the acidified mixture with water or perform liquid-liquid separation, and then perform dehydration and drying to obtain an oily liquid or a liquid with low to medium viscosity. Step S2: Inject liquid into the storage chamber (111), and input water vapor into the connecting pipe (12) at one end of the body (11) by the supply and discharge structure. Then, drive the fan (24) to rotate by the motor (21), thereby driving the water vapor to move along the stripping chamber (112). Step S3: When the motor (21) drives the fan (24) to rotate, the motor (21) synchronously drives the top ring (251) to rotate. The top ring (251) drives the pressure plate (2533) to move up and down in the pressure groove (1111). When the pressure plate (2533) moves down in the pressure groove (1111), the liquid in the pressure groove (1111) is squeezed down by the pressure plate (2533) and passes through the connecting hole (1113) to form a thin fluid and enter the refining groove (1112). Step S4: When the fluid passes through the dropper tube (254), the fluid is cut into droplets by the slice (2541) of the dropper tube (254). Nonaldehyde and water vapor form an azeotrope or an immiscible mixture, thereby extracting and separating the nonaldehyde in the liquid, and then discharging it from the connecting pipe (12) at the other end of the body (11) along the direction of water vapor flow. Step S5: The residual liquid after the separation of nonanal is collected by the collection chamber (113) and discharged downward through the discharge pipe (13) to obtain the azelaic acid precursor residual liquid.

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