Device and process for supercritical CO2 extraction of citrus essential oil

Abstract

The invention discloses a device for extracting citrus essential oil through supercritical CO2, and belongs to the technical field of citrus essential oil extraction, the device comprises an extraction tank internally provided with citrus peels to be extracted, a support frame part used for erecting the extraction tank is arranged on the peripheral side of the extraction tank, an output shaft of a stirring motor penetrates into the extraction tank, and a stirring shaft is fixed to the output shaft of the stirring motor; a plurality of stirring and smashing blades are symmetrically arranged on the peripheral side of the upper portion of the stirring shaft, a grinding lower pressing disc is arranged on the lower portion of the stirring shaft and located on the lower portion of an inner cavity of the extraction tank in a lifting mode, at least two rectangular through grooves are symmetrically formed in the grinding lower pressing disc, and a rectangular lifting block is arranged in each rectangular through groove in a lifting mode; and the bottom surface of the rectangular lifting block is provided with a crushing cutter part for crushing and cutting the orange peel to be extracted. The crushing degree of the orange peels is greatly improved through a double crushing mode, and the effective contact area of the supercritical CO2 solvent and the orange peels is increased, so that the extraction efficiency and quality of the essential oil are remarkably improved.

Description

Technical Field

[0001] The invention belongs to the technical field of extracting citrus essential oil, in particular to a device and a process for extracting citrus essential oil by supercritical CO2. Background Art

[0002] Supercritical CO2 extraction technology is a widely used method for extracting natural products, especially suitable for the extraction of heat-sensitive substances such as citrus essential oils. Traditional supercritical CO2 extraction devices usually include a closed extraction tank, which injects supercritical carbon dioxide as a solvent to dissolve the target component under certain temperature and pressure conditions.

[0003] However, the existing extraction devices have some limitations and shortcomings when processing citrus peels. For example, in the traditional supercritical CO2 extraction process, the initial crushing of citrus peels is usually completed by simple cutting. The degree of crushing obtained by this method is limited, resulting in the effective ingredients inside the citrus peels not being fully exposed to the supercritical CO2 solvent, thereby reducing the extraction efficiency and product quality. At the same time, a single crushing method is difficult to achieve efficient crushing of citrus peels, especially when high yield and high-quality essential oils are required. Existing equipment cannot provide sufficiently fine and uniform crushing effects, affecting the purity and consistency of the final product. Summary of the invention

[0004] The object of the present invention is to provide a device and a process for extracting citrus essential oil by supercritical CO2 to solve the problems raised in the background technology.

[0005] To achieve the above-mentioned purpose, the present invention provides the following technical solutions: a device for extracting citrus essential oil with supercritical CO2, comprising an extraction tank with citrus peel to be extracted, a bracket frame for erecting the extraction tank is arranged on the periphery of the extraction tank, a tank cover is arranged on the top surface of the extraction tank, a stirring motor is installed on the top surface of the tank cover, the output shaft of the stirring motor passes through the extraction tank and is fixed with a stirring shaft, a plurality of stirring and crushing blades are symmetrically arranged on the upper periphery of the stirring shaft, a grinding lower pressure plate is lifted and arranged at the lower part of the stirring shaft and located at the lower part of the inner cavity of the extraction tank, at least two rectangular through grooves are symmetrically opened inside the grinding lower pressure plate, a rectangular lifting block is lifted and arranged in each of the rectangular through grooves, and a crushing cutting knife for crushing and cutting the citrus peel to be extracted is arranged on the bottom surface of the rectangular lifting block.

[0006] Preferably, the top surface of the grinding lower pressure plate is provided with a detachable plate cover by means of bolts, and the peripheral side of the grinding lower pressure plate is connected to the inner wall of the extraction tank by means of a lifting and positioning member.

[0007] Preferably, the lifting and positioning member includes two T-shaped positioning sleeves symmetrically welded to the outer wall of the grinding lower pressure plate and two L-shaped positioning rods symmetrically welded to the inner wall of the extraction tank.

[0008] Preferably, the ends of the two L-shaped positioning rods away from the inner wall of the extraction tank are inserted into the sleeve of the T-shaped positioning sleeve, so that when the grinding lower pressure plate is raised or lowered, the T-shaped positioning sleeve is driven to move up and down around the L-shaped positioning rods for longitudinal lifting and positioning of the grinding lower pressure plate.

[0009] Preferably, a removable top block is embedded in the middle of the top of each rectangular through slot, a waterproof junction box extending into the rectangular through slot is installed on the bottom surface of the removable top block, an electric lifting rod is installed on the bottom surface of the waterproof junction box, and the bottom lifting end of the electric lifting rod is fixedly connected to the rectangular lifting block.

[0010] Preferably, in this solution, an external thread path is provided on the peripheral side of the bottom end of the stirring shaft, and an internal thread path threadedly connected to the external thread path is provided on the longitudinal center axis of the grinding lower pressure plate and the detachable plate cover.

[0011] Preferably, the crushing cutting blade comprises a transverse cutting blade welded to one side of the bottom surface of the rectangular lifting block, a transverse base welded to the other side of the bottom surface of the rectangular lifting block, and a plurality of longitudinal cutting blades equidistantly welded to the bottom surface of the transverse base.

[0012] Preferably, a drive motor is installed on the outside of the support frame, and the output shaft of the drive motor is connected to a connecting block welded to the outer wall of the extraction tank, so that the drive motor can drive the extraction tank to swing left and right.

[0013] Preferably, a support buffer assembly is provided directly below the extraction tank and at the bottom of the bracket frame, and the support buffer assembly includes a hydraulic lifting column for supporting the extraction tank when shaking and mixing are not required and a buffer air spring for providing support, buffering and shock absorption for the extraction tank.

[0014] A process for extracting citrus essential oil by supercritical CO2 comprises the following steps:

[0015] S1. Wash the fresh citrus peels and pour them into the extraction tank for crushing pretreatment. Turn on the stirring motor, which drives the stirring shaft to rotate, and the grinding lower pressure plate starts to rise and fall. When the grinding lower pressure plate descends, it will directly apply pressure to the citrus peels at the bottom of the extraction tank for crushing;

[0016] S2, the rectangular lifting block can move up and down, and the horizontal cutting blade and the vertical cutting blade fixed on the bottom surface of the rectangular lifting block can cut the citrus peel from different directions;

[0017] S3, applying supercritical CO2 fluid to the citrus peel raw material after crushing pretreatment, wherein the temperature of the supercritical CO2 fluid is controlled between 35°C and 45°C, the pressure is maintained in the range of 20MPa to 30MPa, and the CO2 flow rate is set to 20kg to 30kg per hour;

[0018] S4. Pulse pressure regulation is implemented on the supercritical CO2 fluid during the extraction process, that is, the pressure is periodically increased or decreased on the basis of a constant pressure with an amplitude not exceeding ±2MPa, and the frequency range is from once to five times per minute;

[0019] S5. After a preset time, the supercritical CO2 fluid containing citrus essential oil is introduced into at least two separators arranged in series or in parallel, wherein the operating condition of the first separator is to reduce the temperature to 25° C. to 35° C. and maintain a relatively low pressure so that some lighter components can be separated; the second separator further adjusts the temperature and pressure conditions to ensure that the remaining active ingredients are completely precipitated;

[0020] S6, collecting the citrus essential oil obtained from the separator, and post-processing it to finally obtain a high-quality citrus essential oil product;

[0021] S7. Use a combination of heat exchangers and energy-saving compressors to achieve the recycling of CO2.

[0022] Compared with the prior art, the technical effects and advantages of the present invention are as follows:

[0023] The supercritical CO2 extraction device for citrus essential oils introduces a grinding lower platen and a rectangular lifting block inside the platen, which work together to further crush the citrus peels after they are initially cut by the grinding lower platen and the cutting blade driven by the rectangular lifting block. This double crushing method greatly improves the degree of crushing of the citrus peels, increases the effective contact area between the supercritical CO2 solvent and the citrus peels, and thus significantly improves the extraction efficiency and quality of the essential oils.

[0024] The rectangular lifting block is matched with the rectangular through slot, and can be crushed by descending the grinding lower pressure plate, or further crushed by extending the crushing cutter, which increases the flexibility of the processing method.

[0025] The transverse and longitudinal cutting blades can cut the citrus peels from different directions, improving the crushing efficiency. The design of the clamping rubber buffer block and buffer spring helps to stabilize these cutting parts and reduce the risk of damage caused by collision. The presence of the clamping rubber buffer block and buffer spring ensures the stability of the cutting parts during work, prolongs the service life, and maintains good cutting performance.

[0026] The motor drives the extraction tank to swing left and right, which promotes the full mixing of the internal materials. Especially for the citrus peels after the initial crushing, this dynamic mixing helps to crush the materials more thoroughly and improve the extraction effect. After the swinging mixing, the internal crushing cutter is used for secondary crushing, which further improves the degree of crushing of the citrus peels, thereby improving the extraction rate and purity of the essential oil. The swinging mixing driven by the drive motor not only promotes the full mixing of the materials, but also unexpectedly achieves the effect of secondary crushing. The swinging action causes the citrus peels to roll continuously in the tank, increasing their chances of contact with the crushing cutter, further refining the material particles. BRIEF DESCRIPTION OF THE DRAWINGS

[0027] In order to more clearly illustrate the specific implementation methods of the present invention or the technical solutions in the prior art, the drawings required for use in the specific implementation methods or the description of the prior art will be briefly introduced below. Obviously, the drawings described below are some implementation methods of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying creative work.

[0028] Figure 1 It is a structural schematic diagram of the present invention;

[0029] Figure 2 It is a structural schematic diagram of the support and buffer assembly of the present invention;

[0030] Figure 3 It is a schematic diagram of the split structure of the buffer tray of the present invention;

[0031] Figure 4 For the present invention Figure 1 A schematic diagram of the enlarged structure at A in the middle;

[0032] Figure 5 It is a schematic diagram of the installation structure of the stirring shaft of the present invention;

[0033] Figure 6 It is a schematic diagram of the installation structure of the grinding lower platen of the present invention;

[0034] Figure 7 It is a schematic diagram of the disassembly structure of the grinding lower pressure plate and the detachable plate cover of the present invention;

[0035] Figure 8 Schematic diagram of the connection structure of the rectangular lifting block of the present invention

[0036] Fig. 9 It is a schematic structural diagram of a clamping rubber buffer block of the present invention;

[0037] Fig.10 The present invention is a flow chart of a process for extracting citrus essential oil by supercritical CO2.

[0038] Description of reference numerals:

[0039] In the figure: 1. extraction tank; 2. tank cover; 3. stirring motor; 4. horizontal support bottom frame; 5. vertical U-shaped frame; 6. moving wheel; 7. electric control box; 8. push-pull handrail; 9. support beam; 10. support buffer assembly; 11. support chassis; 12. hydraulic lifting column; 13. lifting support plate; 14. buffer air spring; 15. buffer plate; 16. silicone pad; 17. first positioning pole; 18. second positioning pole; 19. connecting block; 20. U-shaped locking block; 21. first locking bolt; 22. second locking bolt Tightening bolts; 23. Driving motor; 24. Stirring shaft; 25. Stirring and crushing blade; 26. Grinding lower pressure plate; 27. Removable plate cover; 28. External thread path; 29. ​​Limiting ring; 30. T-type positioning sleeve; 31. L-type positioning rod; 32. Internal thread path; 33. Rectangular through groove; 34. Removable top block; 35. Waterproof junction box; 36. Electric lifting rod; 37. Rectangular lifting block; 38. Horizontal cutting blade; 39. Horizontal base; 40. Longitudinal cutting blade; 41. Clamping rubber buffer block; 42. Buffer spring. DETAILED DESCRIPTION

[0040] In the following description, a large number of specific details are provided to provide a more thorough understanding of the present invention. However, it is apparent to those skilled in the art that the present invention can be implemented without one or more of these details. In other examples, in order to avoid confusion with the present invention, some technical features well known in the art are not described.

[0041] Unless otherwise defined, the up, down, left, right, front, back, inside and outside directions involved in this document are based on the up, down, left, right, front, back, inside and outside directions in the figures shown in the present invention, and are explained here together.

[0042] This embodiment provides Figures 1 to 10The device for extracting citrus essential oil with supercritical CO2 shown in the figure comprises an extraction tank 1 containing citrus peel to be extracted, a bracket frame for erecting the extraction tank 1 is arranged on the periphery of the extraction tank 1, a tank cover 2 is arranged on the top surface of the extraction tank 1, a stirring motor 3 is installed on the top surface of the tank cover 2, the output shaft of the stirring motor 3 penetrates into the extraction tank 1 and is fixed with a stirring shaft 24, a plurality of stirring and crushing blades 25 are symmetrically arranged on the periphery of the upper part of the stirring shaft 24, and a grinding lower pressure plate 2 is arranged on the lower part of the stirring shaft 24 and is located at the lower part of the inner cavity of the extraction tank 1. 6. At least two rectangular through grooves 33 are symmetrically provided inside the grinding lower platen 26. A rectangular lifting block 37 is lifted and lowered in each rectangular through groove 33. A crushing and cutting blade for crushing and cutting the citrus peel to be extracted is provided on the bottom surface of the rectangular lifting block 37. When the grinding lower platen 26 descends, the citrus peel at the bottom of the inner cavity of the extraction tank 1 is crushed. At the same time, the internal rectangular lifting block 37 descends in the rectangular through groove 33 to drive the crushing and cutting blade to descend and cut the citrus peel. This dual crushing and grinding structure can quickly improve the extraction efficiency and quality of the citrus peel.

[0043] In this embodiment, a removable plate cover 27 is installed on the top surface of the grinding lower platen 26 by bolts, and the peripheral side of the grinding lower platen 26 is connected to the inner wall of the extraction tank 1 by a lifting positioning member.

[0044] In this embodiment, the lifting and positioning member includes two T-shaped positioning sleeves 30 symmetrically welded to the outer wall of the grinding lower pressure plate 26 and two L-shaped positioning rods 31 symmetrically welded to the inner wall of the extraction tank 1 .

[0045] In this embodiment, one end of the two L-shaped positioning rods 31 away from the inner wall of the extraction tank 1 is inserted into the sleeve of the T-shaped positioning sleeve 30, so that when the grinding lower pressure plate 26 is raised or lowered, the T-shaped positioning sleeve 30 is driven to move up and down around the L-shaped positioning rods 31 for the longitudinal lifting and positioning of the grinding lower pressure plate 26.

[0046] In this embodiment, a removable top block 34 is embedded in the middle of the top of each rectangular through slot 33, and a waterproof junction box 35 extending into the rectangular through slot 33 is installed on the bottom surface of the removable top block 34. An electric lifting rod 36 is installed on the bottom surface of the waterproof junction box 35, and the bottom lifting end of the electric lifting rod 36 is fixedly connected to the rectangular lifting block 37. Each waterproof junction box 35 has a battery for powering the adjacent electric lifting rod 36. And the opening and closing of the electric lifting rod 36 is wirelessly controlled by an external button. The removable top block 34 is installed on the grinding lower pressure plate 26 by bolts. When the removable plate cover 27 is installed, the bottom surface of the removable plate cover 27 is pressed down on the top surface of the removable top block 34. The rectangular lifting block 37 is matched with the rectangular through slot 33. When the grinding lower pressure plate 26 descends, it can be crushed by the descending grinding lower pressure plate 26, and can be further crushed by extending the crushing cutter.

[0047] In this embodiment, an external thread path 28 is provided on the circumference of the bottom end of the stirring shaft 24, and an internal thread path 32 threadedly connected to the external thread path 28 is provided on the longitudinal center axis of the grinding lower pressure plate 26 and the removable plate cover 27. When the stirring motor 3 drives the stirring shaft 24 forward and reversely, the grinding lower pressure plate 26 and the removable plate cover 27 are driven to rise and fall. A limit ring 29 is welded above the external thread path 28 and on the circumference of the stirring shaft 24, and the limit ring 29 is used to limit the lifting stroke of the removable plate cover 27.

[0048] In this embodiment, the crushing cutter member includes a transverse cutting blade 38 welded to one side of the bottom surface of the rectangular lifting block 37, a transverse base 39 welded to the other side of the bottom surface of the rectangular lifting block 37, and a plurality of longitudinal cutting blades 40 welded to the bottom surface of the transverse base 39 at equal intervals. The transverse cutting blade 38 and the longitudinal cutting blade 40 can be crushed in different directions. A plurality of clamping rubber buffer blocks 41 are clamped and bonded between the transverse cutting blade 38 and the transverse base 39, and a buffer spring 42 is embedded in each of the clamping rubber buffer blocks 41, and the two ends of the buffer spring 42 are elastically abutted against the inner wall of the transverse base 39 and the transverse cutting blade 38 respectively. The design of the clamping rubber buffer block 41 and the buffer spring 42 contributes to the stable buffering of the transverse cutting blade 38, the transverse base 39 and the longitudinal cutting blade 40.

[0049] In this embodiment, a driving motor 23 is installed on the outside of the bracket frame, and the output shaft of the driving motor 23 is connected to the connecting block 19 welded to the outer wall of the extraction tank 1, so that the driving motor 23 can drive the extraction tank 1 to swing left and right, thereby mixing the citrus peel that has been initially crushed inside. After the swinging and mixing, it is crushed again by the internal crushing and cutting blade to further improve the extraction effect.

[0050] In this embodiment, a support buffer assembly 10 is provided directly below the extraction tank 1 and at the bottom of the support frame. The support buffer assembly 10 includes a hydraulic lifting column 12 for supporting the extraction tank 1 when it does not need to be swung and mixed, and a buffer air spring 14 for providing support, buffering and shock absorption for the extraction tank 1. When the extraction tank 1 needs to be swung and mixed, the hydraulic lifting column 12 and the buffer air spring 14 are synchronously lowered to a safe distance to prevent the swaying of the extraction tank 1 from being hindered.

[0051] In this embodiment, the bracket frame includes a horizontal supporting bottom frame 4, an inverted vertical U-shaped frame 5 symmetrically welded on both sides of the top surface of the horizontal supporting bottom frame 4, moving wheels 6 fixed to the four corners of the bottom surface of the horizontal supporting bottom frame 4, an electric control box 7 installed in one of the vertical U-shaped frames 5, and two push-pull handrails 8 welded above the electric control box 7 and located on the outer wall of the vertical U-shaped frame 5. The electric control box 7 has a PLC for controlling the opening and closing of various electronic components.

[0052] In this embodiment, the support and buffering assembly 10 also includes support beams 9 symmetrically welded to the top surfaces of both sides of the horizontal support bottom frame 4 and a support chassis 11 welded between the two support beams 9. The hydraulic lifting column 12 is fixedly installed on the top surface of the support chassis 11. A lifting support plate 13 is welded to the top lifting end of the hydraulic lifting column 12. A plurality of buffer air springs 14 are fixed in an annular array on the top surface of the lifting support plate 13. A buffer plate 15 is fixed at the top end of the plurality of buffer air springs 14. A silicone pad 16 is bonded to the top surface of the buffer plate 15. The silicone pad 16 elastically abuts against the bottom surface of the extraction tank 1. A plurality of first positioning rods 17 are welded in an annular array on the bottom surface of the lifting support plate 13. The first positioning rod 17 longitudinally penetrates the support chassis 11. A plurality of second positioning rods 18 are welded in an annular array on the bottom surface of the buffer plate 15. The second positioning rod 18 longitudinally penetrates the lifting support plate 13. The second positioning rod 18 is used to position the buffer air spring 14 to buffer the longitudinal movement. The first positioning rod 17 is used for longitudinal positioning of the hydraulic lifting column 12.

[0053] In this embodiment, the driving motor 23 is fixed on the outer wall of one of the vertical U-shaped frames 5, and the output shaft of the driving motor 23 passes through the vertical U-shaped frame 5 and is fixedly connected to the connecting block 19. When it is not necessary to swing the extraction tank 1, a U-shaped locking block 20 is installed between the connecting block 19 and the top surface of the vertical U-shaped frame 5, and the U-shaped locking block 20 is connected to the connecting block 19 through a first locking bolt 21, and the U-shaped locking block 20 is connected to the vertical U-shaped frame 5 through a second locking bolt 22, thereby improving the stability of the extraction tank 1. When it is necessary to swing the extraction tank 1, the U-shaped locking block 20 can be removed to open the driving motor 23 to swing and mix the extraction tank 1.

[0054] A process for extracting citrus essential oil by supercritical CO2 comprises the following steps:

[0055] S1, wash the fresh citrus peel and pour it into the extraction tank 1 for crushing pretreatment, turn on the stirring motor 3, the stirring motor 3 drives the stirring shaft 24 to rotate, and the grinding lower pressing plate 26 starts to rise and fall. When the grinding lower pressing plate 26 descends, it will directly apply pressure to the citrus peel at the bottom of the extraction tank 1 to crush it;

[0056] S2, the rectangular lifting block 37 can move up and down, and the transverse cutting blade 38 and the longitudinal cutting blade 40 fixed on the bottom surface of the rectangular lifting block 37 can cut the citrus peel from different directions;

[0057] S3, applying supercritical CO2 fluid to the citrus peel raw material after crushing pretreatment, wherein the temperature of the supercritical CO2 fluid is controlled between 35°C and 45°C, the pressure is maintained in the range of 20MPa to 30MPa, and the CO2 flow rate is set to 20kg to 30kg per hour;

[0058] S4. Pulse pressure regulation is applied to the supercritical CO2 fluid during the extraction process, i.e., the pressure is periodically increased or decreased by no more than ±2MPa on the basis of a constant pressure, with a frequency ranging from once to five times per minute, so as to promote material transfer and enhance the extraction effect;

[0059] S5. After a preset time (e.g., 60 minutes), the supercritical CO2 fluid containing citrus essential oil is introduced into at least two separators arranged in series or in parallel, wherein the operating condition of the first separator is to reduce the temperature to 25° C. to 35° C. and maintain a relatively low pressure so that some lighter components can be separated; the second separator further adjusts the temperature and pressure conditions to ensure that the remaining active ingredients are completely precipitated;

[0060] S6, collecting the citrus essential oil obtained from the separator, and performing post-processing such as filtering and clarifying on the citrus essential oil, and finally obtaining a high-quality citrus essential oil product;

[0061] S7. Combining heat exchangers with energy-saving compressors can achieve the recycling of CO2, reducing operating costs while reducing environmental impact.

[0062] Working principle:

[0063] The device for extracting citrus essential oil with supercritical CO2 opens the tank cover 2 and puts the citrus peel to be extracted into the extraction tank 1. Close and tighten the tank cover 2 to ensure the sealing, and use the PLC control system in the electric control box 7 to set the extraction parameters, including temperature, pressure, time, and whether shaking and mixing are required. Adjust the height of the hydraulic lifting column 12 as required, so that the buffer air spring 14 is in a position that does not affect the swing, start the stirring motor 3, and drive the stirring and crushing blade 25 to rotate through the stirring shaft 24, and perform preliminary cutting and crushing of the citrus peel to increase the material contact area in preparation for subsequent extraction. Start the stirring motor 3, and drive the stirring and crushing blade 25 to rotate through the stirring shaft 24, and perform preliminary cutting and crushing of the citrus peel to increase the material contact area in preparation for subsequent extraction.

[0064] As the extraction process proceeds, the grinding lower platen 26 will descend according to the preset required program to crush the citrus peel at the bottom. At the same time, the rectangular lifting block 37 in the rectangular through slot 33 will also descend, so that the transverse cutting blade 38 and the longitudinal cutting blade 40 fixed thereon will further cut and crush the citrus peel. This dual crushing mechanism can significantly improve the extraction efficiency. According to the required set program, the grinding lower platen 26 begins to descend, and the rectangular lifting block 37 is lifted and lowered in the rectangular through slot 33 symmetrically opened inside it. When the grinding lower platen 26 descends, it will directly apply pressure to the citrus peel at the bottom of the extraction tank 1 for crushing. A waterproof junction box 35 is installed below the removable top block 34 embedded in the middle of the top of the rectangular through slot 33, which contains an electric lifting rod 36. The electric lifting rod 36 is controlled by the PLC system, and it can independently drive the rectangular lifting block 37 to move up and down. The bottom surface of the rectangular lifting block 37 is fixed with a transverse cutting blade 38 and a longitudinal cutting blade 40, which can cut the citrus peel from different directions. The clamping rubber buffer block 41 and the buffer spring 42 ensure that the cutter element remains stable during the cutting process and reduces damage caused by vibration.

[0065] The hydraulic lifting column 12 in the support buffer assembly 10 is used to adjust the height of the extraction tank 1. When swinging and mixing are not required, the hydraulic lifting column 12 is raised, so that the buffer air spring 14 is in a supporting state; when swinging is required, the hydraulic lifting column 12 is lowered to a safe distance to avoid hindering the swinging movement. The buffer air spring 14 is installed on the lifting support plate 13, and its top end is connected to the buffer plate 15, and elastically abuts against the bottom of the extraction tank 1 through the silicone cushion layer 16. This can effectively absorb the impact force caused by swinging or other operations, protect the equipment and maintain smooth operation. The first positioning rod 17 and the second positioning rod 18 pass through the support chassis 11 and the lifting support plate 13 respectively, providing a precise longitudinal movement path for the hydraulic lifting column 12 and the buffer air spring 14 to ensure their stability and reliability.

[0066] Before the shaking and mixing is required, it is first necessary to loosen the U-shaped locking block 20 between the connecting block 19 and the vertical U-shaped frame 5. This step is completed by the cooperation of the first locking bolt 21 and the second locking bolt 22 to release the freedom of the extraction tank 1. Once the U-shaped locking block 20 is removed, the drive motor 23 fixed to the outer wall of the vertical U-shaped frame 5 can be started. The output shaft of the motor directly drives the extraction tank 1 to shake left and right through the connecting block 19. The shaking action not only promotes the full mixing of the citrus peel, but also allows the crushed material to be subjected to the action of the internal crushing cutter again, achieving a more thorough crushing effect. This dynamic mixing helps to improve the extraction efficiency and quality.

[0067] When the extraction cycle is completed, all moving parts are stopped, the supercritical CO2 solvent in the extraction tank 1 is emptied, and the extracted essential oil is collected.

[0068] It should be noted that, in this article, relational terms such as one and two are only used to distinguish one entity or operation from another entity or operation, and do not necessarily require or imply any such actual relationship or order between these entities or operations. Moreover, the terms "include", "comprise" or any other variants thereof are intended to cover non-exclusive inclusion, so that a process, method, article or device including a series of elements includes not only those elements, but also other elements not explicitly listed, or also includes elements inherent to such process, method, article or device. In the absence of further restrictions. The sentence "includes an element defined by ... does not exclude the existence of other identical elements in the process, method, article or device including the element".

[0069] Although embodiments of the present invention have been shown and described, it will be appreciated by those skilled in the art that various changes, modifications, substitutions and variations may be made to the embodiments without departing from the principles and spirit of the present invention, and that the scope of the present invention is defined by the appended claims and their equivalents.

Claims

1. A device for extracting citrus essential oil using supercritical CO2, comprising an extraction tank (1) containing citrus peel to be extracted, a support frame for mounting the extraction tank (1) being arranged on the periphery of the extraction tank (1), characterized in that: The top surface of the extraction tank (1) is provided with a tank cover (2), and a stirring motor (3) is installed on the top surface of the tank cover (2). The output shaft of the stirring motor (3) penetrates into the extraction tank (1) and is fixed with a stirring shaft (24). A plurality of stirring and crushing blades (25) are symmetrically arranged around the upper part of the stirring shaft (24). A grinding lower pressing plate (26) is lifted and arranged at the lower part of the inner cavity of the extraction tank (1) and the lower part of the stirring shaft (24). At least two rectangular through grooves (33) are symmetrically opened inside the grinding lower pressing plate (26). A rectangular lifting block (37) is lifted and arranged in each of the rectangular through grooves (33). A crushing cutting blade for crushing and cutting the citrus peel to be extracted is arranged on the bottom surface of the rectangular lifting block (37).

2. The device for supercritical CO2 extraction of citrus essential oil according to claim 1, characterized in that: A detachable plate cover (27) is mounted on the top surface of the grinding lower platen (26) via bolts, and the peripheral side of the grinding lower platen (26) is connected to the inner wall of the extraction tank (1) via a lifting and positioning member.

3. The device for supercritical CO2 extraction of citrus essential oil according to claim 2, characterized in that: The lifting and positioning member comprises two T-shaped positioning sleeves (30) symmetrically welded to the outer wall of the grinding lower pressure plate (26) and two L-shaped positioning rods (31) symmetrically welded to the inner wall of the extraction tank (1).

4. The device for supercritical CO2 extraction of citrus essential oil according to claim 3, characterized in that: One end of the two L-shaped positioning rods (31) away from the inner wall of the extraction tank (1) is inserted into the sleeve of the T-shaped positioning sleeve (30), so that when the grinding lower pressure plate (26) is raised or lowered, the T-shaped positioning sleeve (30) is driven to move up and down around the L-shaped positioning rods (31) for longitudinal lifting and positioning of the grinding lower pressure plate (26).

5. The device for supercritical CO2 extraction of citrus essential oil according to claim 4, characterized in that: A detachable top block (34) is embedded in the middle of the top of each rectangular through slot (33); a waterproof junction box (35) extending into the rectangular through slot (33) is installed on the bottom surface of the detachable top block (34); an electric lifting rod (36) is installed on the bottom surface of the waterproof junction box (35); and the bottom lifting end of the electric lifting rod (36) is fixedly connected to the rectangular lifting block (37).

6. The device for supercritical CO2 extraction of citrus essential oil according to claim 5, characterized in that: An external thread path (28) is arranged on the peripheral side of the bottom end of the stirring shaft (24), and an internal thread path (32) threadedly connected to the external thread path (28) is provided on the longitudinal center axis of the grinding lower pressure plate (26) and the detachable plate cover (27).

7. The device for supercritical CO2 extraction of citrus essential oil according to claim 6, characterized in that: The crushing and cutting blade component comprises a transverse cutting blade (38) welded to one side of the bottom surface of a rectangular lifting block (37), a transverse base (39) welded to the other side of the bottom surface of the rectangular lifting block (37), and a plurality of longitudinal cutting blades (40) welded to the bottom surface of the transverse base (39) at equal intervals.

8. The device for supercritical CO2 extraction of citrus essential oil according to claim 7, characterized in that: A driving motor (23) is installed outside the support frame, and an output shaft of the driving motor (23) is connected to a connecting block (19) welded to the outer wall of the extraction tank (1), so that the driving motor (23) can drive the extraction tank (1) to swing left and right.

9. The device for supercritical CO2 extraction of citrus essential oil according to claim 8, characterized in that: A support buffer assembly (10) is provided directly below the extraction tank (1) and at the bottom of the support frame. The support buffer assembly (10) comprises a hydraulic lifting column (12) for supporting the extraction tank (1) when shaking and mixing are not required, and a buffer air spring (14) for providing support, buffering and shock absorption for the extraction tank (1).

10. A process for extracting citrus essential oil by supercritical CO2, using the device for extracting citrus essential oil by supercritical CO2 according to any one of claims 1 to 9, characterized in that: The following steps are involved: S1, fresh citrus peels are washed and poured into the extraction tank (1) for crushing pretreatment, the stirring motor (3) is turned on, the stirring motor (3) drives the stirring shaft (24) to rotate, and the grinding lower pressing plate (26) starts to rise and fall. When the grinding lower pressing plate (26) descends, it directly applies pressure to the citrus peels at the bottom of the extraction tank (1) to crush them; S2, the rectangular lifting block (37) can move up and down, and the transverse cutting blade (38) and the longitudinal cutting blade (40) fixed on the bottom surface of the rectangular lifting block (37) can cut the citrus peel from different directions; S3, applying supercritical CO2 fluid to the citrus peel raw material after crushing pretreatment, wherein the temperature of the supercritical CO2 fluid is controlled between 35°C and 45°C, the pressure is maintained in the range of 20MPa to 30MPa, and the CO2 flow rate is set to 20kg to 30kg per hour; S4. Pulse pressure regulation is implemented on the supercritical CO2 fluid during the extraction process, that is, the pressure is periodically increased or decreased on the basis of a constant pressure with an amplitude not exceeding ±2MPa, and the frequency range is from once to five times per minute; S5. After a preset time, the supercritical CO2 fluid containing citrus essential oil is introduced into at least two separators arranged in series or in parallel, wherein the operating condition of the first separator is to reduce the temperature to 25° C. to 35° C. and maintain a relatively low pressure so that some lighter components can be separated; the second separator further adjusts the temperature and pressure conditions to ensure that the remaining active ingredients are completely precipitated; S6, collecting the citrus essential oil obtained from the separator, and post-processing it to finally obtain a high-quality citrus essential oil product; S7. Use a combination of heat exchangers and energy-saving compressors to achieve the recycling of CO2.

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