Supercritical carbon dioxide extraction separation system and method based on extrusion expansion

Abstract

The invention belongs to the field of chemical separation and bioengineering mechanical equipment, and provides a supercritical carbon dioxide extraction separation system and method based on extrusion expansion. The system is composed of a refrigeration pressurization circulation subsystem, an extrusion expansion subsystem, a jet flow feeding subsystem, a continuous flow extraction loop subsystem, an extract depressurization separation subsystem and a raffinate separation subsystem, all the subsystems work cooperatively, and continuous production and recycling of carbon dioxide are achieved. The method and the system are widely applied to the field of extraction of grease, natural product effective components, heat-sensitive biological medicines and the like, and have remarkable technical advantages and market prospects. The method comprises the steps of extrusion puffing, presoaking, supercritical fluid extraction, separation of extract and raffinate and the like, the permeability of a material is improved by extruding and puffing the material to be extracted, and the power consumption is reduced, the extraction time is shortened and the extraction efficiency is improved by utilizing the excellent permeability and solubility of supercritical carbon dioxide.

Description

Technical Field

[0001] The invention belongs to the technical field of chemical separation, bioengineering machinery and equipment and agricultural product processing, and in particular relates to a supercritical carbon dioxide extraction and separation system and method based on extrusion puffing. Background Art

[0002] The statements in this section merely provide background information related to the present invention and do not necessarily constitute prior art.

[0003] As an advanced processing method, material extrusion and puffing technology has been widely used in the field of effective ingredient extraction and food processing in recent years. This technology uses the combined effects of high temperature, high pressure and high shear force to puff the material, thereby significantly improving its processing efficiency and product quality. Although traditional extrusion and puffing material technology has improved production efficiency to a certain extent, under high temperature and high pressure environments, heat-sensitive components in the material, such as vitamins and amino acids, are often easily damaged, affecting the nutritional value of the product.

[0004] In the field of modern separation technology, supercritical carbon dioxide extraction technology has become a key process for the extraction of active ingredients from natural products, separation of food-grade functional substances, and development of high value-added biological resources due to its environmental friendliness, low operating temperature characteristics, and high selectivity. However, the intermittent fixed bed extraction mode commonly used in existing industrial equipment has significant technical defects: first, the static bed structure leads to low solid-fluid two-phase contact efficiency, the mass transfer path is too long, and the diffusion rate of effective ingredients is limited; second, batch operations require repeated opening of the extraction kettle for material loading and unloading and system pressure relief, which not only reduces the supercritical fluid circulation efficiency, but also aggravates the mechanical fatigue and energy loss of the equipment sealing structure; third, the operation process with frequent manual intervention is prone to oxidative inactivation of heat-sensitive substances, and there are safety hazards in production. This field requires an innovative solution that can enhance the solid-fluid mass transfer efficiency and achieve continuous operation. Summary of the invention

[0005] In order to solve the above problems, the present invention proposes a supercritical carbon dioxide extraction and separation system and method based on extrusion puffing. The present invention utilizes supercritical carbon dioxide to assist in extrusion puffing technology. Through the mechanical effects of the extrusion puffing machine such as stirring, mixing, shearing and extrusion, the cell wall is destroyed, the channel is opened, and the effective ingredients overflow and disperse on the surface of the material. At the same time, supercritical carbon dioxide is introduced as a puffing agent, which effectively reduces the temperature requirement required for the puffing process, thereby significantly reducing the loss of heat-sensitive components. Finally, it is instantly extruded from the die hole of the extrusion puffing machine, and the supercritical carbon dioxide is transformed into a gaseous state to form a loose and porous puffed material, which increases the permeability of the material, thereby shortening the supercritical extraction time, improving the extraction efficiency, and realizing a continuous, efficient and energy-saving separation technology to meet the growing market demand.

[0006] According to some embodiments, the first solution of the present invention provides a supercritical carbon dioxide extraction and separation system based on extrusion expansion, which adopts the following technical solution:

[0007] A supercritical carbon dioxide extraction and separation system based on extrusion expansion includes a refrigeration and pressurization circulation subsystem, wherein the refrigeration and pressurization circulation subsystem is respectively connected with an extrusion expansion subsystem, a jet feeding subsystem, an extract decompression separation subsystem, and a raffinate separation subsystem;

[0008] The extrusion and puffing subsystem includes an extrusion and puffing machine, a cyclone separator, a puffing material tank, and a prepreg tank which are connected in sequence; the extrusion and puffing machine is also connected to the refrigeration and pressurization circulation subsystem through a sixth stop valve, and supercritical carbon dioxide is used to assist in extrusion and puffing of the material to be extracted; and the extrusion and puffing machine is also connected to a demister, a carbon dioxide collection tank, and a compressor in sequence; the prepreg tank is also connected to the refrigeration and pressurization circulation subsystem through an eleventh stop valve to obtain supercritical carbon dioxide; the prepreg tank is also connected to the jet feeding subsystem through a third discharge valve.

[0009] Further, the jet feeding subsystem is composed of one or more jet feeders, and the jet feeder is connected to the extrusion and expansion subsystem through a feed valve;

[0010] The jet feeding subsystem is connected to the refrigeration pressurization circulation subsystem through the twelfth stop valve, and the twelfth stop valve is connected to the second pressurization pump and the supercritical carbon dioxide storage tank in sequence. The supercritical carbon dioxide storage tank is connected to the continuous flow extraction circuit subsystem through the fifteenth stop valve, and the supercritical carbon dioxide storage tank is also connected to the jet feeder.

[0011] Furthermore, the low-pressure phase inlet of the jet feeder is connected to the pre-preg tank in the extrusion and expansion subsystem, and the jet feeder transports the pre-preg material to be extracted to the continuous flow extraction circuit subsystem;

[0012] The supercritical carbon dioxide storage tank is connected to the high-pressure phase inlet of the jet feeder, so that the supercritical carbon dioxide in the supercritical carbon dioxide storage tank serves as the high-pressure working fluid of the jet feeder.

[0013] Furthermore, the refrigeration and pressurization circulation subsystem includes a carbon dioxide cylinder, a carbon dioxide storage tank, a refrigerator, a first pressure pump, a thermostat, and a supercritical carbon dioxide buffer tank connected in sequence; the supercritical carbon dioxide buffer tank is connected to the extrusion puffing machine in the extrusion puffing subsystem; the carbon dioxide storage tank is respectively connected to the extract pressure reduction separation subsystem and the extract residue separation subsystem.

[0014] Furthermore, the continuous flow extraction circuit subsystem is composed of one or more extraction kettles, the feed inlet of the extraction kettle is connected to the jet feeder of the jet feeding subsystem, the discharge port at the lower end of the extraction kettle is connected to the extract separation subsystem; the overflow port at the upper part of the extraction kettle is connected to the extract pressure reduction separation subsystem;

[0015] The overflow port at the top of the extraction kettle is also connected to the bottom reflux port of the extraction kettle through a circulation pump.

[0016] Furthermore, a swirl distributor is provided at the bottom of the extraction kettle, and the uniformity of fluid injection is adjusted by an inclined nozzle in the swirl distributor.

[0017] Furthermore, the extract pressure reduction and separation subsystem includes a first pressure regulating valve, a pressure reducing kettle, a second pressure regulating valve, a heat exchanger, and a separation kettle which are sequentially connected; the bottom of the pressure reducing kettle is connected to a second discharge valve, the bottom of the separation kettle is connected to a third discharge valve, and the separation kettle is connected to the refrigeration and pressurization circulation subsystem through a twenty-first stop valve;

[0018] The extract pressure reduction and separation subsystem is connected to the continuous flow extraction circuit subsystem through a twelfth stop valve.

[0019] Furthermore, the raffinate separation subsystem includes a gas-solid separator and a slag storage tank; the gas-solid separator is connected to the continuous flow extraction circuit subsystem through a twenty-second stop valve; the gas-solid separator is also connected to the refrigeration pressurization circulation subsystem;

[0020] The bottom of the gas-solid separator is also connected to a slag storage tank, and the bottom of the slag storage tank is connected to a fourth discharge valve.

[0021] Furthermore, the extrusion puffing machine is provided with a constant temperature heating device in sections, and the constant temperature heating device is used to control the temperature of the barrel of the extrusion puffing machine according to different materials to be extracted.

[0022] According to some embodiments, the second solution of the present invention provides a supercritical carbon dioxide extraction and separation method based on extrusion expansion, which adopts the following technical solution:

[0023] A supercritical carbon dioxide extraction and separation method based on extrusion expansion, based on a supercritical carbon dioxide extraction and separation system based on extrusion expansion described in the first scheme, comprising:

[0024] The material to be extracted is expanded in the extrusion puffing machine through mechanical actions such as extrusion, kneading, shearing and pressurization, as well as the auxiliary action of supercritical carbon dioxide;

[0025] The expanded material enters the pre-preg tank, and the penetration and dissolution effect of supercritical carbon dioxide is used to dissolve the effective components in the cell structure of the material in advance;

[0026] The prepreg is fed tangentially into the extraction kettle through the jet feeding subsystem for fluidized continuous extraction. The supercritical carbon dioxide carrying the solute flows out from the overflow port at the top of the extraction kettle and re-enters the extraction kettle through the circulation pump. When the supercritical carbon dioxide in the kettle is saturated or nearly saturated, the saturated carbon dioxide is discharged into the extract pressure reduction and separation subsystem, and fresh carbon dioxide is introduced; the extraction process is repeated until the prepreg is completely extracted.

[0027] Finally, the saturated carbon dioxide carrying the solute is discharged from the overflow port of the extraction kettle into the extract pressure reduction and separation subsystem. After two pressure reduction separations, the extract is precipitated and collected, and the carbon dioxide is collected and recycled.

[0028] After the extract is completely separated, the carbon dioxide fluid carrying the residue flows into the residue separation subsystem through the twenty-second stop valve to separate the residue from the carbon dioxide, collect the residue, and collect and recycle the carbon dioxide.

[0029] Compared with the prior art, the present invention has the following beneficial effects:

[0030] The present invention converts the material into a fluffy and porous structure, thereby significantly increasing the reaction area of ​​the material in contact with the solvent in the leaching stage and the fluidized extraction stage, and at the same time increasing the permeability of the material, promoting the penetration and diffusion of the solvent in the extraction kettle, achieving a more thorough extraction effect, and thus improving the extraction efficiency and extraction rate.

[0031] The present invention adds a pre-impregnation process after puffing, and pre-impregnates the puffed material in supercritical carbon dioxide. As the cell wall of the material is destroyed and the internal channel is opened after the extrusion and puffing, the supercritical carbon dioxide can penetrate into the material more quickly, and the pre-impregnation is equivalent to static extraction before fluidized extraction, which further shortens the overall extraction time. At the same time, the traditional fixed bed extraction is converted into fluidized extraction, and the continuous extraction process is realized, so that the supercritical carbon dioxide and the material to be extracted are fully disturbed and contacted in the extraction kettle, the extraction efficiency is improved, and the problems of long extraction time, uneven extraction, large workload, high cost, etc. of the existing device and process are solved.

[0032] The present invention avoids the use of high temperature treatment in the traditional extrusion process by optimizing temperature control, thereby achieving energy conservation and protection of the nutritional components of the material. Specifically, this process maintains a relatively low temperature setting during the extrusion process, effectively avoiding the damage of high temperature to the protein activity and heat-sensitive components in the material, while retaining the original flavor of the effective ingredients; at the same time, through the parallel extraction kettle and circulation pump design, supercritical carbon dioxide is self-circulated in the extraction kettle, reducing the use of solvents, forming a fluidized vortex in the extraction kettle, and enhancing the mass transfer effect through shear force and particle impact, achieving an energy-saving, efficient and environmentally friendly extraction process.

[0033] The present invention is a technological innovation based on the principle of fluidization engineering. By constructing a dynamically suspended solid-fluid contact system, it can break through the physical mass transfer limitations of the traditional fixed bed. This technology enables solid particles to form a fluid-like motion state in a supercritical fluid, significantly increasing the mass transfer contact area and shortening the diffusion path of the effective ingredients. Combined with the continuous feeding and discharging design, the operational redundancy of repeated opening and closing of equipment in traditional processes is avoided, thereby systematically reducing energy consumption and the intensity of manual intervention. This type of technological upgrade not only meets the urgent need of green manufacturing processes for efficient and energy-saving equipment, but also provides an innovative technical path for the application of supercritical extraction technology in the large-scale processing of natural products. BRIEF DESCRIPTION OF THE DRAWINGS

[0034] The accompanying drawings in the specification, which constitute a part of the present invention, are used to provide a further understanding of the present invention. The exemplary embodiments of the present invention and their descriptions are used to explain the present invention and do not constitute improper limitations on the present invention.

[0035] Figure 1 This is a structural diagram of a supercritical carbon dioxide extraction and separation system based on extrusion puffing in an embodiment of the present invention;

[0036] Reference numerals:

[0037] 1. Refrigeration and pressurization circulation subsystem: 1-1, carbon dioxide gas cylinder, 1-2, first stop valve, 1-3, carbon dioxide storage tank, 1-4, second stop valve, 1-5, refrigerator, 1-6, third stop valve, 1-7, first pressure pump, 1-8, fourth stop valve, 1-9, thermostat, 1-10, first check valve, 1-11, supercritical carbon dioxide buffer tank, 1-12, fifth stop valve;

[0038] 2. Extrusion and puffing subsystem: 2-1. The sixth stop valve, 2-2. Extrusion and puffing machine, 2-3. Receiving tank, 2-4. The first discharge valve, 2-5. The first discharge valve, 2-6. Cyclone separator, 2-7. The second discharge valve, 2-8. The seventh stop valve, 2-9. Demister, 2-10. The eighth stop valve, 2-11. The ninth stop valve, 2-12. Carbon dioxide collection tank, 2-13. The tenth stop valve, 2-14. Compressor, 2-15. The first drain valve, 2-16. Puffing tank, 2-17. The second drain valve, 2-18. Gate valve, 2-19. Balance valve, 2-20. Pre-soaking tank, 2-21. The eleventh stop valve, 2-22. The third discharge valve;

[0039] 3. Jet feeding subsystem: 3-1, twelfth stop valve, 3-2, second booster pump; 3-3, thirteenth stop valve, 3-4, supercritical carbon dioxide storage tank, 3-5, fourteenth stop valve, 3-6, fifteenth stop valve, 3-7-1 to 3-7-N, feed valve, 3-8-1 to 3-8-N, inlet valve, 3-9-1 to 3-9-N, jet feeder;

[0040] 4. Continuous flow extraction circuit subsystem: 4-1-1 to 4-1-N, extraction kettle, 4-2-1 to 4-2-N, outlet valve, 4-3-1 to 4-3-N, sixteenth stop valve, 4-4-1 to 4-4-N, circulation pump, 4-5-1 to 4-5-N, seventeenth stop valve, 4-6-1 to 4-6-N, second one-way valve, 4-7-1 to 4-7-N, eighteenth stop valve, 4-8-1 to 4-8-N, nineteenth stop valve, 4-9-1 to 4-9-N, fourth discharge valve;

[0041] 5. Extract pressure reduction and separation subsystem: 5-1, 20th stop valve, 5-2, first pressure regulating valve, 5-3, pressure reducing kettle, 5-4, second pressure regulating valve, 5-5, heat exchanger, 5-6, separation kettle, 5-7, 21st stop valve, 5-8, third drain valve, 5-9, second discharge valve, 5-10, third discharge valve;

[0042] 6. Extract separation subsystem: 6-1. 22nd stop valve, 6-2. Gas-solid separator, 6-3. 23rd stop valve, 6-4. 3rd check valve, 6-5. 4th drain valve, 6-6. 5th discharge valve, 6-7. Slag storage tank, 6-8. 4th unloading valve. DETAILED DESCRIPTION

[0043] The present invention will be further described below in conjunction with the accompanying drawings and embodiments.

[0044] It should be noted that the following detailed descriptions are all illustrative and intended to provide further explanation of the present invention. Unless otherwise specified, all technical and scientific terms used herein have the same meanings as those commonly understood by those skilled in the art to which the present invention belongs.

[0045] It should be noted that the terms used herein are only for describing specific embodiments and are not intended to limit exemplary embodiments according to the present invention. As used herein, unless the context clearly indicates otherwise, the singular form is also intended to include the plural form. In addition, it should be understood that when the terms "comprising" and / or "including" are used in this specification, it indicates the presence of features, steps, operations, devices, components and / or combinations thereof.

[0046] In the absence of conflict, the embodiments of the present invention and the features of the embodiments may be combined with each other.

[0047] Embodiment 1

[0048] like Figure 1As shown, this embodiment provides a supercritical carbon dioxide extraction and separation system based on extrusion expansion, which is composed of a refrigeration and pressurization circulation subsystem 1, an extrusion expansion subsystem 2, a jet feeding subsystem 3, a continuous flow extraction circuit subsystem 4, an extract depressurization separation subsystem 5 and an extract residue separation subsystem 6; the refrigeration and pressurization circulation subsystem 1 is respectively connected with the extrusion expansion subsystem 2, the jet feeding subsystem 3, the extract depressurization separation subsystem 5 and the extract residue separation subsystem 6, and the continuous flow extraction circuit subsystem 4 is respectively connected with the jet feeding subsystem 3, the extract depressurization separation subsystem 5 and the extract residue separation subsystem 6. In this embodiment, the cell wall of the material to be extracted is destroyed by extruding, the internal channel is opened, and a loose porous structure is formed by expansion to increase the permeability of the material, and then the expanded material is placed in supercritical carbon dioxide for pre-impregnation, and then the pre-impregnated material to be extracted is sent to the extraction kettle for fluidized continuous extraction, and carbon dioxide circulates in the system.

[0049] (1) The extrusion and expansion subsystem 2 includes a sixth stop valve 2-1, an extrusion and expansion machine 2-2, a receiving tank 2-3, a first discharge valve 2-4, a first outlet valve 2-5, a cyclone separator 2-6, a second outlet valve 2-7, a seventh stop valve 2-8, a demister 2-9, an eighth stop valve 2-10, a ninth stop valve 2-11, a carbon dioxide collection tank 2-12, a tenth stop valve 2-13, a compressor 2-14, a first drain valve 2-15, The puffing material tank 2-16, the second drain valve 2-17, the gate valve 2-18, the balancing valve 2-19, the pre-impregnation tank 2-20, the eleventh stop valve 2-21, and the third discharge valve 2-22; the first discharge valve 2-4 and the eighth stop valve 2-10 are respectively arranged at the bottom of the receiving tank 2-3 and the demister 2-9, and the extrusion puffing subsystem 2 is used to perform supercritical carbon dioxide assisted extrusion puffing on the material, and to mix the puffed material to be extracted with supercritical carbon dioxide for pre-impregnation.

[0050] Specifically, the extrusion and expansion subsystem 2 is connected to the refrigeration and pressurization circulation subsystem 1 through the sixth stop valve 2-1; the sixth stop valve 2-1 is connected to the extrusion and expansion machine 2-2, the first discharge valve 2-5, the cyclone separator 2-6, the second discharge valve 2-7, the expansion tank 2-16, and the prepreg tank 2-20 in sequence; a gate valve 2-18 and a balance valve 2-19 are provided between the expansion tank 2-16 and the prepreg tank 2-20; wherein the expansion tank 2-16 is also connected to the second emptying valve 2-17; the extrusion and expansion machine 2-2 is also connected to the receiving tank 2-3 and the first discharge valve 2-4 in sequence;

[0051] The cyclone separator 2-6 is also connected in sequence to the seventh stop valve 2-8, the demister 2-9, the ninth stop valve 2-11, the carbon dioxide collecting tank 2-12 and the compressor 2-14; wherein, the demister 2-9 is also connected to the eighth stop valve 2-10; the carbon dioxide collecting tank 2-12 is connected to the first drain valve 2-15; the compressor 2-14 is connected to the tenth stop valve 2-13 on both sides; the compressor 2-14 is also connected to the fifth stop valve 1-12 through the pipeline A to achieve communication with the refrigeration pressurization circulation subsystem 1.

[0052] The prepreg tank 2-20 is also connected to the refrigeration and pressurization circulation subsystem 1 through the eleventh stop valve 2-21 to obtain supercritical carbon dioxide; the prepreg tank 2-20 is also connected to the jet feeding subsystem 3 through the third discharge valve 2-22.

[0053] The extruder 2-2 is provided with a constant temperature heating device, and the barrel temperature of the extruder is controlled according to different materials to ensure the best expansion effect. The type of the extruder is not limited, and it can be a twin-screw extruder or a single-screw extruder. By injecting supercritical carbon dioxide into the extruder, the expansion of the material to be extracted is promoted, and the extrusion temperature is reduced, thereby reducing the damage of heat-sensitive substances.

[0054] The cleaned and impurity-free materials are added to the extrusion puffing machine 2-2. After stirring, mixing, shearing and extrusion in the front half of the extrusion puffing machine 2-2, the cell wall of the material is destroyed, and the effective ingredients overflow and are collected in the receiving tank 2-3 through the pressing cage of the extrusion puffing machine 2-2; the supercritical carbon dioxide provided by the refrigeration and pressurization circulation subsystem 1 is added to the middle and rear sections of the extrusion puffing machine 2-2 through the sixth stop valve 2-1, and the supercritical carbon dioxide is mixed with the material in the extrusion puffing machine 2-2; at the end of the extrusion screw, the material is extruded through the die head, and due to the sudden pressure relief, the carbon dioxide changes from the supercritical state to the gaseous state, the material expands rapidly to obtain a loose and porous puffed material, and the cell wall is further destroyed; the puffed material is then cut into uniform particles by a cutter. The gaseous carbon dioxide carries the expanded particles through the cyclone separator 2-6, and the separated carbon dioxide enters the carbon dioxide collection tank 2-12 through the seventh stop valve 2-8, the demister 2-9, and the ninth stop valve 2-11, and then is pressurized by the compressor 2-14 and sent back to the refrigeration and pressurization circulation subsystem 1 for recycling; the separated expanded material falls into the expanded material tank 2-16 for storage through the second discharge valve 2-7, then the expanded material tank balance valve 2-19 is opened to balance the pressure between the expanded material tank 2-16 and the prepreg tank 2-20, and then the expanded material tank gate valve 2-18 is opened, and the expanded material falls into the prepreg tank 2-20 by gravity after being measured. According to the solid-liquid ratio set by the process conditions, a certain amount of supercritical carbon dioxide is injected from the supercritical carbon dioxide buffer tank 1-11 through the eleventh stop valve 2-21 into the prepreg tank 2-20, and the supercritical carbon dioxide penetrates and diffuses into the material, dissolves the effective components, and provides static extraction pretreatment before fluidized extraction. The extrusion and expansion subsystem 2 is used to perform supercritical carbon dioxide-assisted extrusion and expansion of the material to be extracted, store the expanded material, and pre-impregnate it.

[0055] The extrusion puffing machine uses supercritical carbon dioxide to assist in extrusion puffing of materials. After mechanical actions such as stirring, mixing, shearing and extrusion in the extrusion puffing machine 2-2, the material cells are destroyed more thoroughly, and the effective components in the cells are fully exposed. The front half of the extrusion puffing machine 2-2 is provided with a pressing cage, and some high-content effective components are collected through the pressing cage, such as high-content oil in oil. The middle and rear sections of the extrusion puffing machine are provided with a carbon dioxide injection port, and the supercritical carbon dioxide prepared by the refrigeration and pressurization circulation subsystem is injected and mixed with the material. Finally, at the end of the extrusion screw, the material comes out through the die head. Due to the sudden pressure relief, the carbon dioxide changes from the supercritical state to the gaseous state, and the material expands rapidly to obtain a loose and porous extrusion puffing material. The puffed material is extruded by the extrusion die head and cut into uniform particles, and then enters the cyclone separator 2-6 through pneumatic conveying. The separated carbon dioxide enters the carbon dioxide collection tank 2-12 through the demister, and then is re-sent to the refrigeration and pressurization circulation subsystem 1 after being pressurized by the compressor 2-14; the separated puffed material enters the puffing material tank 2-16 for storage and standby. The expanded material is measured according to the process flow and falls into the prepreg tank 2-20 by gravity; then the supercritical carbon dioxide in the supercritical carbon dioxide buffer tank 1-11 is injected into the prepreg tank 2-20 for prepreg. During the prepreg, the supercritical carbon dioxide penetrates into the material to dissolve the effective ingredients, achieving a static extraction effect to reduce the overall extraction time.

[0056] (2) The refrigeration and pressurization circulation subsystem 1 includes a carbon dioxide gas cylinder 1-1, a first stop valve 1-2, a carbon dioxide storage tank 1-3, a second stop valve 1-4, a refrigerator 1-5, a first pressure pump 1-7, a fourth stop valve 1-8, a thermostat 1-9, a first check valve 1-10, and a supercritical carbon dioxide buffer tank 1-11, which are connected in sequence, and also includes a third stop valve 1-6, and the first pressure pump 1-7 and the third stop valve 1-6 are arranged in parallel, so that the two sides of the third stop valve 1-6 are connected to the two sides of the first pressure pump 1-7. The supercritical carbon dioxide buffer tank 1-11 is connected to the extrusion extruder 2-2 in the extrusion extrusion subsystem 2; the carbon dioxide storage tank 1-3 is connected to the extract pressure reduction separation subsystem 5 and the raffinate separation subsystem 6 respectively, and the carbon dioxide storage tank 1-3 is also connected to the fifth stop valve 1-12, and the fifth stop valve 1-12 is also connected to the compressor 2-14 through the pipeline A.

[0057] The gaseous carbon dioxide in the carbon dioxide cylinder 1-1 or recovered by the separation subsystem enters the carbon dioxide storage tank 1-3 through the first stop valve 1-2, and then enters the refrigerator 1-5 through the second stop valve 1-4. The gaseous carbon dioxide is liquefied by the refrigerator 1-5, and then the liquid carbon dioxide is pressurized to the required pressure for pre-infusion by the first booster pump 1-7. The liquid carbon dioxide coming out of the first booster pump 1-7 is heated by the thermostat 1-9 and converted into supercritical carbon dioxide fluid and enters the supercritical carbon dioxide buffer tank 1-11. The refrigeration and pressurization circulation subsystem 1 is used for the preparation of supercritical carbon dioxide.

[0058] (3) The jet feeding subsystem 3 includes a twelfth stop valve 3-1, a second pressure pump 3-2; a thirteenth stop valve 3-3, a supercritical carbon dioxide storage tank 3-4, a fourteenth stop valve 3-5, a fifteenth stop valve 3-6, feed valves 3-7-1 to 3-7-N, inlet valves 3-8-1 to 3-8-N, and jet feeders 3-9-1 to 3-9-N.

[0059] Specifically, the jet feeding subsystem 3 is connected to the refrigeration pressurization circulation subsystem 1 through the twelfth stop valve 3-1, and the twelfth stop valve 3-1 is connected to the second booster pump 3-2, the supercritical carbon dioxide storage tank 3-4 and the fifteenth stop valve 3-6 in sequence, and the fifteenth stop valve 3-6 is connected to the continuous flow extraction circuit subsystem 4; wherein, the second booster pump 3-2 is also connected to the thirteenth stop valve 3-3 on both sides; the second booster pump 3-2 pressurizes the supercritical carbon dioxide to the pressure required for extraction and stores it in the supercritical carbon dioxide storage tank 3-4, and serves as the high-pressure working fluid of the jet feeders 3-9-1 to 3-9-N, and the low-pressure phase inlet of the jet feeder is connected to the prepreg tank 2-20, which is used to transport the prepreg material to be extracted to the continuous flow extraction circuit subsystem 4;

[0060] The supercritical carbon dioxide storage tank 3-4 is also connected in sequence to the fourteenth stop valve 3-5, the inlet valves 3-8-1 to 3-8-N, and the jet feeders 3-9-1 to 3-9-N; wherein the jet feeders 3-9-1 to 3-9-N are also connected to the third discharge valve 2-22 in the extrusion puffing subsystem 2 through the feed valves 3-7-1 to 3-7-N.

[0061] The supercritical carbon dioxide from the refrigeration and pressurization circulation subsystem 1 is pressurized through the twelfth stop valve 3-1 and the second pressure pump 3-2 and is stored in the supercritical carbon dioxide storage tank 3-4, and is used to add fresh supercritical carbon dioxide to the extraction kettle through the fifteenth stop valve 3-6, or is used to provide a high-pressure source for the jet feeders 3-9-1 to 3-9-N through the fourteenth stop valve 3-5 and the inlet valves 3-8-1 to 3-8-N; after the prepreg is completed, the material in the prepreg tank is connected to the low-pressure phase inlet of the jet feeder 3-9-1 to 3-9-N through the third discharge valve 2-22 and the feed valves 3-7-1 to 3-7-N, and the prepreg material to be extracted is sprayed into the continuous flow extraction circuit subsystem 4.

[0062] It can be understood that the jet feeding subsystem has one or more parallel jet feeders 3-9-1 to 3-9-N, which correspondingly contain the same number of inlet valves 3-8-1 to 3-8-N and feed valves 3-7-1 to 3-7-N.

[0063] The jet feeder subsystem 3 is used to transport the prepreg to the continuous flow extraction circuit subsystem 4. The jet feeders 3-9-1 to 3-9-N are provided with heating devices to compensate for the pressure and temperature losses caused by the nozzle throttling effect. The supercritical carbon dioxide supplied by the refrigeration and pressurization circulation subsystem 1 is further pressurized by the second booster pump 3-2 and stored in the supercritical carbon dioxide storage tank 3-4. On the one hand, it is connected to the bottom of the extraction kettle 4-1-1 to 4-1-N as the extraction medium of the continuous flow extraction circuit subsystem 4, and on the other hand, it is connected to the high-pressure phase inlet of the jet feeder 3-9-1 to 3-9-N as the high-pressure working fluid of the jet feeder 3-9-1 to 3-9-N. The prepreg tank 2-20 is connected to the low-pressure phase inlet of the jet feeder 3-9-1 to 3-9-N, so that the prepreg material to be extracted is ejected and tangentially fed into the extraction kettle 4-1-1 to 4-1-N.

[0064] (4) The continuous flow extraction circuit subsystem 4 includes extraction kettles 4-1-1 to 4-1-N, outlet valves 4-2-1 to 4-2-N, sixteenth stop valves 4-3-1 to 4-3-N, circulation pumps 4-4-1 to 4-4-N, seventeenth stop valves 4-5-1 to 4-5-N, second one-way valves 4-6-1 to 4-6-N, eighteenth stop valves 4-7-1 to 4-7-N, nineteenth stop valves 4-8-1 to 4-8-N, and fourth discharge valves 4-9-1 to 4-9-N. The continuous flow extraction circuit subsystem 4 is used for fluidized extraction of pre-leaching materials to be extracted. After the extraction is completed, the extract is transported to the extract depressurization separation subsystem 5 for separation, and the raffinate is transported to the raffinate separation subsystem 6 for separation.

[0065] Specifically, the inlet of the extraction kettle 4-1-1 to 4-1-N is connected to the jet feeder 3-9-1 to 3-9-N of the jet feeding subsystem 3, and the lower end outlet of the extraction kettle 4-1-1 to 4-1-N is connected to the raffinate separation subsystem 6 through the fourth discharge valve 4-9-1 to 4-9-N;

[0066] The upper overflow port of the extraction kettle 4-1-1 to 4-1-N is connected to the extract pressure reduction separation subsystem 5 through the outlet valve 4-2-1 to 4-2-N, and the upper overflow port of the extraction kettle 4-1-1 to 4-1-N is also connected to the bottom of the extraction kettle 4-1-1 to 4-1-N through the sixteenth stop valve 4-3-1 to 4-3-N, the circulation pump 4-4-1 to 4-4-N, the second one-way valve 4-6-1 to 4-6-N, and the eighteenth stop valve 4-7-1 to 4-7-N to realize the self-circulation of supercritical carbon dioxide, wherein both ends of the circulation pump 4-4-1 to 4-4-N are also connected to the seventeenth stop valve 4-5-1 to 4-5-N.

[0067] It can be understood that the continuous flow extraction circuit subsystem is composed of one or more parallel extraction kettles 4-1-1 to 4-1-N and circulation pumps 4-4-1 to 4-4-N; the extraction kettle is provided with a feed inlet, a discharge port, an overflow port and a bottom reflux port, and the overflow port is provided with a filter screen to filter the material and discharge the supercritical carbon dioxide; a cyclone distributor is provided at the bottom of the extraction kettle to form a cyclone fluidization, and the inclined nozzle in the distributor can improve the uniformity of the fluid injection, so that the material and the fluid can be more fully contacted, which will increase the contact opportunity between the material and the fluid, and for the falling material, it will be blown up multiple times, increasing the interaction opportunity between the supercritical fluid and the particles. When extraction is carried out in the extraction kettle, the expanded material is pre-impregnated in the pre-impregnation tank.

[0068] The pre-impregnated material enters the extraction kettle 4-1-1 to 4-1-N tangentially through the extraction kettle inlet through the jet feeder 3-9-1 to 3-9-N to form a fluidized cyclone. The supercritical carbon dioxide interacts with the material and is crushed by shear force and impact between particles to improve the extraction efficiency. During the extraction process, the supercritical carbon dioxide fluid rich in solute is discharged through the overflow port of the extraction kettle 4-1-1 to 4-1-N, and then is recirculated by the circulation pump 4-4-1 to 4-4-N from the bottom reflux port of the extraction kettle 4-1-1 to 4-1-N through the cyclone distributor. The carbon dioxide is newly transported back to the extraction kettles 4-1-1 to 4-1-N until the supercritical carbon dioxide reaches or approaches saturation, and the saturated carbon dioxide enters the extract pressure reduction separation subsystem 5 from the overflow port; to ensure that the effective components of the material are completely extracted, fresh carbon dioxide can enter again from the bottom of the extraction kettles 4-1-1 to 4-1-N and repeat the above process until the effective components are completely extracted; after the carbon dioxide carrying the solute is discharged, the residue after extraction, that is, the extract residue is discharged into the extract separation subsystem 6 through the discharge port of the extraction kettles 4-1-1 to 4-1-N.

[0069] The jet feeders 3-9-1 to 3-9-N inject the pre-impregnated materials to be extracted in the pre-impregnation tank 2-20 into the extraction kettles 4-1-1 to 4-1-N in a tangential direction, and the materials form a fluidized vortex in the extraction kettle, which promotes the mutual collision and full mixing between the material particles. The extraction kettles 4-1-1 to 4-1-N are equipped with a constant temperature heating device, which is used to heat the mixed materials in the extraction kettles 4-1-1 to 4-1-N to the specific temperature required by the supercritical carbon dioxide under the set extraction pressure according to the process requirements, so as to maintain the supercritical state of carbon dioxide and achieve the stability of the extraction temperature. The overflow port at the top of the extraction kettle 4-1-1 to 4-1-N is provided with two routes: one is connected to the carbon dioxide loop to realize the self-circulation of supercritical carbon dioxide, and the other is connected to the extract pressure reduction separation subsystem 5. After the feeding is completed, the jet feeder 3-9-1 to 3-9-N is closed, and the sixteenth stop valve 4-3-1 to 4-3-N is opened to allow the supercritical carbon dioxide carrying the solute to re-enter the kettle from the bottom of the extraction kettle through the circulation pump 4-4-1 to 4-4-N, the second one-way valve 4-6-1 to 4-6-N, and the eighteenth stop valve 4-7-1 to 4-7-N. A cyclone distributor is provided at the bottom of the extraction kettle, so that the supercritical carbon dioxide forms a cyclone in the kettle, thereby achieving uniform distribution of the gas and improving the overall mass transfer efficiency. When the supercritical carbon dioxide is close to saturation, the sixteenth stop valve 4-3-1 to 4-3-N is closed, and the outlet valve 4-2-1 to 4-2-N is opened to send the saturated carbon dioxide into the extract pressure reduction separation subsystem 5.

[0070] To ensure that the material to be extracted in the kettle can be completely extracted, open the fifteenth stop valve 3-6 and the nineteenth stop valves 4-8-1 to 4-8-N, send fresh supercritical carbon dioxide in the supercritical carbon dioxide storage tank 3-4 into the kettle, open the carbon dioxide loop, and repeat the above steps until the effective components of the material to be extracted are completely extracted, and then the residue enters the residue separation subsystem 6 through the fourth discharge valve 4-9-1 to 4-9-N.

[0071] (5) The extract pressure reduction and separation subsystem 5 includes a twentieth stop valve 5-1, a first pressure regulating valve 5-2, a pressure reducing kettle 5-3, a second pressure regulating valve 5-4, a heat exchanger 5-5, a separation kettle 5-6, and a twenty-first stop valve 5-7, which are connected in sequence; a second discharge valve 5-9 and a third discharge valve 5-10 are respectively arranged at the bottom of the pressure reducing kettle 5-3 and the separation kettle 5-6.

[0072] Specifically, the extract pressure reduction and separation subsystem 5 is connected to the continuous flow extraction circuit subsystem 4 through the twelfth stop valve 5-1, and the twelfth stop valve 5-1 is connected in sequence to the first pressure regulating valve 5-2, the pressure reducing kettle 5-3, the second pressure regulating valve 5-4, the heat exchanger 5-5, the separation kettle 5-6 and the third emptying valve 5-8, wherein the pressure reducing kettle 5-3 is also connected to the second unloading valve 5-9; the separation kettle 5-6 is also connected to the third unloading valve 5-10; the separation kettle 5-6 is also connected to the carbon dioxide storage tank 1-3 of the refrigeration and pressurization circulation subsystem 1 through the twenty-first stop valve 5-7.

[0073] The saturated supercritical carbon dioxide carrying solute enters the first pressure regulating valve 5-2 through the twelfth stop valve 5-1 and flows into the pressure reducing kettle 5-3. After the first throttling action, the temperature and pressure of the supercritical carbon dioxide are reduced, and the solute is precipitated in the pressure reducing kettle; the supercritical carbon dioxide after temperature and pressure reduction enters the separation kettle 5-6 through the second pressure regulating valve 5-4 and the heat exchanger 5-5. After the second throttling action, this process further reduces the pressure of the supercritical carbon dioxide, prompting it to change from a critical state to a gaseous state, so that all the solutes dissolved therein are precipitated and retained in the separation kettle 5-6 in liquid form, and the gaseous carbon dioxide re-enters the refrigeration and pressurization circulation subsystem through the twenty-first stop valve 5-7 to achieve recycling. To prevent the freezing phenomenon caused by the excessively low temperature during the second throttling and pressure reduction process, the system uses the waste heat generated in the refrigeration and pressurization circulation subsystem 1 to exchange heat with the heat exchanger 5-5 to maintain a suitable operating temperature.

[0074] The extract depressurization and separation subsystem 5 is designed to effectively separate the extract from the saturated supercritical carbon dioxide. The saturated carbon dioxide carrying the solute is depressurized by throttling through two pressure regulating valves, and the extract is separated in the separation kettle. At the same time, the separated carbon dioxide is sent to the refrigeration and pressurization circulation subsystem for recycling. In order to prevent dry ice from being generated due to the throttling effect during the depressurization process and clogging the pipeline, a heat exchanger is added after the second pressure regulating valve to stabilize the separation temperature and improve the overall efficiency of the system; this design not only ensures the efficient separation of the extract, but also optimizes the recycling of carbon dioxide.

[0075] (6) The extract separation subsystem 6 includes a twenty-second stop valve 6-1, a gas-solid separator 6-2, a twenty-third stop valve 6-3, a third one-way valve 6-4, a fourth drain valve 6-5, a fifth discharge valve 6-6, a slag storage tank 6-7, and a fourth discharge valve 6-8; the fourth discharge valve 6-8 is arranged at the bottom of the slag discharge tank 6-7.

[0076] Specifically, the residue separation subsystem 6 is connected to the continuous flow extraction circuit subsystem 4 through the twenty-second stop valve 6-1; the twenty-second stop valve 6-1 is connected to the gas-solid separator 6-2, the fifth discharge valve 6-6, the slag storage tank 6-7 and the fourth unloading valve 6-8 in sequence; the gas-solid separator 6-2 is also connected to the twenty-third stop valve 6-3, the third one-way valve 6-4 and the fourth drain valve 6-5 in sequence; the third one-way valve 6-4 is also connected to the carbon dioxide storage tank 1-3 of the refrigeration and pressurization circulation subsystem 1; the twenty-second stop valve 6-1 is also connected to the fourth discharge valves 4-9-1 to 4-9-N of the continuous flow extraction circuit subsystem 4.

[0077] The carbon dioxide carrying the residue flows out from the fourth discharge valve 4-9-1 to 4-9-N of the continuous flow extraction loop subsystem 4, and is then introduced into the gas-solid separator 6-2 through the twenty-second stop valve 6-1. The separated carbon dioxide re-enters the carbon dioxide storage tank 1-3 through the twenty-third stop valve 6-3 and the third one-way valve 6-4. The residue enters the slag storage tank 6-7 through the fifth discharge valve 6-6, and the slag is discharged through the fourth discharge valve 6-8.

[0078] The residue separation subsystem 6 is used to effectively separate the slag and carbon dioxide. In the system, the inlet of the gas-solid separator 6-2 is connected to the discharge port of the extraction kettle, and the gas phase outlet of the gas-solid separator 6-2 is connected to the refrigeration pressurization circulation subsystem 1 for recycling; and the solid phase outlet of the gas-solid separator 6-2 is connected to the slag storage tank 6-7 to collect the discharged slag.

[0079] Embodiment 2

[0080] This embodiment provides a supercritical carbon dioxide extraction and separation method based on extrusion expansion, and a supercritical carbon dioxide extraction and separation system based on extrusion expansion described in Embodiment 1, comprising:

[0081] First, the material to be extracted is placed in an extrusion puffing machine 2-2, and the material is puffed through mechanical actions such as extrusion, kneading, shearing and pressurization, as well as the auxiliary action of supercritical carbon dioxide, so that the cells in the material are completely destroyed, the effective ingredients are fully exposed, and harmful substances are passivated. In the first half of the extrusion puffing machine 2-2, some effective ingredients are extruded and collected by the pressing cage. At the end of the extrusion screw, the material is extruded through the die head under high pressure, and the sudden drop in pressure causes the supercritical carbon dioxide to expand rapidly in the material, forming a loose porous structure to improve the permeability of the material. Subsequently, the puffed material is cut into uniform particles by a cutter to ensure its efficient fluidity and uniformity in the subsequent fluidized pneumatic conveying and extraction process, thereby significantly improving the extraction efficiency and the extraction rate of the target components in the material.

[0082] The expanded material is then placed in a pre-preg tank 2-20, and the penetration and dissolution effect of supercritical carbon dioxide is used to preliminarily dissolve the effective components in the cell structure of the material, thereby achieving efficient extraction of the effective components in the subsequent supercritical carbon dioxide extraction process.

[0083] The prepreg is then tangentially fed into the extraction kettle 4-2-1 to 4-2-N through the jet feeding subsystem 3 for fluidized continuous extraction. The supercritical carbon dioxide carrying the solute flows out from the overflow port at the upper end of the extraction kettle 4-2-1 to 4-2-N and re-enters the extraction kettle 4-2-1 to 4-2-N through the circulation pump 4-4-1 to 4-4-N. After the supercritical carbon dioxide in the kettle is saturated or nearly saturated, the saturated carbon dioxide is discharged into the extract pressure reduction and separation subsystem 5, and fresh carbon dioxide is introduced; the extraction process is repeated until the prepreg is completely extracted.

[0084] Finally, the saturated carbon dioxide carrying the solute is discharged from the overflow ports of the extraction kettles 4-2-1 to 4-2-N into the extract pressure reduction and separation subsystem 5. After two pressure reduction separations, the extract is precipitated and collected, and the carbon dioxide is collected and recycled;

[0085] After the extract is completely separated, the carbon dioxide fluid carrying the residue flows into the residue separation subsystem 6 through the twenty-second stop valve to separate the residue from the carbon dioxide, collect the residue, and collect and recycle the carbon dioxide.

[0086] Specifically, the detailed process of this method is as follows:

[0087] (1) System emptying:

[0088] First, the refrigeration pressurization circulation subsystem 1 and the extrusion expansion subsystem 2 are emptied. The gaseous carbon dioxide in the carbon dioxide cylinder 1-1 enters the carbon dioxide storage tank 1-3 through the first stop valve 1-2, and then enters the supercritical carbon dioxide buffer tank 1-11 through the second stop valve 1-4, the refrigerator 1-5, the third stop valve 1-6, the fourth stop valve 1-8, the thermostat 1-9, and the first check valve 1-10. One way passes through the sixth stop valve 2-1, the extrusion expansion machine 2-2, the first discharge valve 2-5, the cyclone separator 2-6, the seventh stop valve 2-8, the demister 2-9, the eighth stop valve 2-10, and the ninth stop valve 2-11 to enter the carbon dioxide collection tank 2-12, and is emptied through the first emptying valve 2-15; the other way enters the prepreg tank 2-20 through the eleventh stop valve 2-21, enters the expansion tank 2-16 through the balance valve 2-19, and is emptied through the second emptying valve 2-17.

[0089] Then, the jet feeding subsystem 3, the continuous extraction subsystem 4, the extract decompression separation subsystem 5 and the raffinate separation subsystem 6 are emptied. The twelfth stop valve 3-1 is opened, and the carbon dioxide in the supercritical carbon dioxide buffer tank 1-11 enters the supercritical carbon dioxide storage tank 3-4 through the twelfth stop valve 3-1 and the thirteenth stop valve 3-3; then, the third discharge valve 2-22, the fourteenth stop valve 3-5, the feed valves 3-7-1 to 3-7-N, and the inlet valves 3-8-1 to 3-8-N are opened to allow the carbon dioxide gas to enter the extraction kettle 4-1-1 to 4-1-N through the jet feeder 3-9-1 to 3-9-N, and the outlet valves 4-2-1 to 4-2-N are opened, and the carbon dioxide enters the extraction kettle 4-1-1 to 4-1-N through the twentieth stop valve 5-1, the fourteenth stop valve 3-5, the feed valves 3-7-1 to 3-7-N, and the inlet valves 3-8-1 to 3-8-N. The first pressure regulating valve 5-2, the pressure reducing kettle 5-3, the second pressure regulating valve 5-4, the heat exchanger 5-5, and the separation kettle 5-6 are discharged from the third drain valve 5-8, and the extract pressure reducing separation subsystem 5 is completely emptied; then the third drain valve 5-8 and the outlet valves 4-2-1 to 4-2-N are closed, and the fourth discharge valve 4-9-1 to 4-9-N are opened, and the carbon dioxide is discharged from the fourth drain valve 6-5 through the twenty-second stop valve 6-1, the gas-solid separator 6-2, the twenty-third stop valve 6-3, and the third one-way valve 6-4, and the residue separation subsystem 6 and the continuous flow extraction loop subsystem 4 are completely emptied.

[0090] (2) Preparation of supercritical carbon dioxide:

[0091] After the system is emptied, the refrigerator 1-5 is turned on to convert the gaseous carbon dioxide into liquid, and then the first booster pump 1-7 is turned on to pressurize the liquefied carbon dioxide to the pressure required for pre-impregnation, and enters the supercritical carbon dioxide buffer tank 1-11 through the fourth stop valve 1-8, the thermostat 1-9, and the first one-way valve 1-10 for standby use.

[0092] (3) Extrusion and pre-preg:

[0093] The extrusion puffing machine 2-2 is started, and the raw materials after cleaning are added to the extrusion puffing machine 2-2, and the sixth stop valve 2-1 is opened, and the supercritical fluid in the supercritical carbon dioxide buffer tank 1-11 is injected into the extrusion puffing machine 2-2. After the supercritical carbon dioxide extrusion puffing machine undergoes mechanical actions such as stirring, mixing, shearing and extrusion, the temperature of the materials increases, and the materials are formed into puffed materials by the extrusion die under the action of the extrusion puffing machine 2-2 and the auxiliary action of the supercritical carbon dioxide, and the supercritical carbon dioxide is converted into a gaseous state. A cutter is provided in the extrusion puffing machine 2-2, and the puffed materials are cut into uniform particles by the cutter after extrusion and sent to the cyclone separator 2-6. The seventh stop valve 2-8 and the second discharge valve 2-7 are opened, and the separated carbon dioxide enters the carbon dioxide collection tank 2-12 through the seventh stop valve 2-8, the demister 2-9, and the ninth stop valve 2-11, and then is sent back to the refrigeration and pressurization circulation subsystem 1 for recycling after being pressurized by the compressor 2-14; the separated puffed materials fall into the puffing material tank 2-16 for storage through the second discharge valve 2-7. Open the balancing valve 2-19 of the expanded material tank 2-16 to balance the pressure of the expanded material tank 2-16 and the prepreg tank 2-20, then open the gate valve 2-18 of the expanded material tank, and the expanded material falls into the prepreg tank 2-20 by gravity after being measured. According to the solid-liquid ratio set by the process conditions, open the eleventh stop valve 2-21 to introduce supercritical carbon dioxide into the prepreg tank 2-20, then close the eleventh stop valve 2-21, and the expanded material is prepregged;

[0094] (4) Feeding and fluidized extraction:

[0095] The twelfth stop valve 3-1 is opened, and the supercritical carbon dioxide is further pressurized to the pressure required for extraction through the second pressure pump 3-2 and stored in the supercritical carbon dioxide storage tank 3-4 for use in the next step. After the pre-impregnation is completed, the third discharge valve 2-22, the fourteenth stop valve 3-5, the feed valves 3-7-1 to 3-7-N, and the inlet valves 3-8-1 to 3-8-N are opened, and the pre-impregnated material to be extracted is tangentially injected into the extraction kettle 4-1-1 to 4-1-N through the jet feeder 3-9-1 to 3-9-N with the high-pressure carbon dioxide in the supercritical carbon dioxide storage tank 3-4 as the working fluid, and the constant temperature heater of the extraction kettle is turned on to keep the carbon dioxide in a supercritical state to ensure that the extraction temperature is stable, and then the sixteenth stop valve 4-3-1 to 4-3-N, the circulation pump 4-4-1 to 4-4-N, the second one-way valve 4-6-1 to 4-6-N, and the eighteenth stop valve 4-7-1 to 4-7-N are opened to re-enter the bottom of the extraction kettle, and a swirling fluidization is formed under the action of the distributor until the supercritical carbon dioxide is saturated or close to saturation, the supercritical carbon dioxide self-circulation is stopped, and the outlet valves 4-2-1 to 4-2 -N, the supercritical carbon dioxide carrying the solute is sent to the extract depressurization separation subsystem 5; then the outlet valves 4-2-1 to 4-2-N are closed, and according to the process requirements, the fifteenth stop valve 3-6 and the nineteenth stop valves 4-8-1 to 4-8-N are opened to allow a quantitative amount of fresh supercritical carbon dioxide to be injected into the extraction kettles 4-1-1 to 4-1-N, and the supercritical carbon dioxide self-circulation is restarted to ensure that the effective extract is completely extracted; repeat the above steps until the extraction is completed, stop the supercritical carbon dioxide self-circulation, open the fifteenth stop valve 3-6, the outlet valves 4-2-1 to 4-2-N, and the nineteenth stop valves 4-8-1 to 4-8-N, and the supercritical carbon dioxide carrying the solute is sent to the extract depressurization separation subsystem 5; then the outlet valves 4-2-1 to 4-2-N are closed, and the fourth discharge valves 4-9-1 to 4-9-N are opened, and the supercritical carbon dioxide carrying the residue is sent to the residue separation subsystem 6;

[0096] When the material is being extracted, the pre-impregnation step of the expanded material is carried out at the same time. When the extraction is completed, the material in the pre-impregnation tank 2-20 is re-injected into the extraction kettles 4-1-1 to 4-1-N for extraction, and then the above process is repeated.

[0097] (5) Separation of extract and residue:

[0098] The supercritical carbon dioxide fluid carrying the extract enters the pressure reducing kettle 5-3 through the 20th stop valve 5-1 and the first pressure regulating valve 5-2. In the pressure reducing kettle 5-3, the pressure of the supercritical carbon dioxide decreases, and the temperature also decreases due to the throttling effect, at which time some solutes will precipitate. The supercritical carbon dioxide after temperature and pressure reduction passes through the second pressure regulating valve 5-4, and undergoes the second throttling effect. This process further reduces the temperature and pressure of the supercritical carbon dioxide, prompting it to change from a critical state to a gaseous state, so that all the solutes dissolved therein are precipitated and retained in the separation kettle 5-6 in liquid form. The gaseous carbon dioxide returns to the carbon dioxide storage tank 1-3 of the refrigeration and pressurization circulation subsystem 1 through the 21st stop valve 5-7 to achieve recycling and cyclic utilization. After the extract is completely separated, the carbon dioxide fluid carrying the raffinate flows into the gas-solid separator 6-2 through the 22nd stop valve 6-1. In the gas-solid separator 6-2, the separated pure carbon dioxide first passes through the 23rd stop valve 6-3 and the third one-way valve 6-4 to re-enter the carbon dioxide storage tank 1-3 for storage in preparation for the subsequent extraction process, thereby achieving efficient recovery and reuse of carbon dioxide. The raffinate is discharged into the slag storage tank 6-7 through the fifth discharge valve 6-6, and the slag is discharged through the discharge valve 6-8.

[0099] Although the above describes the specific implementation mode of the present invention in conjunction with the accompanying drawings, it is not intended to limit the scope of protection of the present invention. Those skilled in the art should understand that various modifications or variations that can be made by those skilled in the art on the basis of the technical solution of the present invention without creative work are still within the scope of protection of the present invention.

Claims

1. A supercritical carbon dioxide extraction and separation system based on extrusion expansion, characterized in that: It includes a refrigeration and pressurization circulation subsystem, which is connected to the extrusion and expansion subsystem, the jet feeding subsystem, the extract decompression separation subsystem and the raffinate separation subsystem respectively; The extrusion and puffing subsystem includes an extrusion and puffing machine, a cyclone separator, a puffing material tank, and a prepreg tank which are connected in sequence; the extrusion and puffing machine is also connected to the refrigeration and pressurization circulation subsystem through a sixth stop valve, and supercritical carbon dioxide is used to assist in extrusion and puffing of the material to be extracted; and the extrusion and puffing machine is also connected to a demister, a carbon dioxide collection tank, and a compressor in sequence; the prepreg tank is also connected to the refrigeration and pressurization circulation subsystem through an eleventh stop valve to obtain supercritical carbon dioxide; the prepreg tank is also connected to the jet feeding subsystem through a third discharge valve.

2. A supercritical carbon dioxide extraction and separation system based on extrusion expansion as claimed in claim 1, characterized in that: The jet feeding subsystem is composed of one or more jet feeders, and the jet feeder is connected to the extrusion and expansion subsystem through a feed valve; The jet feeding subsystem is connected to the refrigeration pressurization circulation subsystem through the twelfth stop valve, and the twelfth stop valve is connected to the second pressurization pump and the supercritical carbon dioxide storage tank in sequence. The supercritical carbon dioxide storage tank is connected to the continuous flow extraction circuit subsystem through the fifteenth stop valve, and the supercritical carbon dioxide storage tank is also connected to the jet feeder.

3. A supercritical carbon dioxide extraction and separation system based on extrusion expansion as claimed in claim 2, characterized in that: The low-pressure phase inlet of the jet feeder is connected to the pre-preg tank in the extrusion and expansion subsystem, and the jet feeder transports the pre-preg material to be extracted to the continuous flow extraction circuit subsystem; The supercritical carbon dioxide storage tank is connected to the high-pressure phase inlet of the jet feeder, so that the supercritical carbon dioxide in the supercritical carbon dioxide storage tank serves as the high-pressure working fluid of the jet feeder.

4. The supercritical carbon dioxide extraction and separation system based on extrusion expansion according to claim 1, characterized in that: The refrigeration and pressurization circulation subsystem includes a carbon dioxide gas cylinder, a carbon dioxide storage tank, a refrigerator, a first pressurizing pump, a thermostat, and a supercritical carbon dioxide buffer tank which are connected in sequence; the supercritical carbon dioxide buffer tank is connected to the extrusion puffing machine in the extrusion puffing subsystem; the carbon dioxide storage tank is respectively connected to the extract pressure reduction separation subsystem and the extract residue separation subsystem.

5. The supercritical carbon dioxide extraction and separation system based on extrusion expansion as claimed in claim 1, characterized in that: The continuous flow extraction circuit subsystem is composed of one or more extraction kettles, the feed port of the extraction kettle is connected to the jet feeder of the jet feeding subsystem, the discharge port at the lower end of the extraction kettle is connected to the extract separation subsystem; the overflow port at the top of the extraction kettle is connected to the extract pressure reduction separation subsystem; The overflow port at the top of the extraction kettle is also connected to the bottom reflux port of the extraction kettle through a circulation pump.

6. A supercritical carbon dioxide extraction and separation system based on extrusion expansion as claimed in claim 5, characterized in that: A cyclone distributor is arranged at the bottom of the extraction kettle, and the uniformity of fluid injection is adjusted by the inclined nozzles in the cyclone distributor.

7. The supercritical carbon dioxide extraction and separation system based on extrusion expansion as claimed in claim 1, characterized in that: The extract pressure reduction and separation subsystem comprises a first pressure regulating valve, a pressure reducing kettle, a second pressure regulating valve, a heat exchanger, and a separation kettle which are sequentially connected; the bottom of the pressure reducing kettle is connected to a second discharge valve, the bottom of the separation kettle is connected to a third discharge valve, and the separation kettle is connected to the refrigeration and pressurization circulation subsystem through a twenty-first stop valve; The extract pressure reduction and separation subsystem is connected to the continuous flow extraction circuit subsystem through a twelfth stop valve.

8. The supercritical carbon dioxide extraction and separation system based on extrusion expansion as claimed in claim 1, characterized in that: The raffinate separation subsystem includes a gas-solid separator and a slag storage tank; the gas-solid separator is connected to the continuous flow extraction circuit subsystem through a twenty-second stop valve; the gas-solid separator is also connected to the refrigeration pressurization circulation subsystem; The bottom of the gas-solid separator is also connected to a slag storage tank, and the bottom of the slag storage tank is connected to a fourth discharge valve.

9. The supercritical carbon dioxide extraction and separation system based on extrusion expansion as claimed in claim 1, characterized in that: The extrusion puffing machine is provided with a constant temperature heating device in sections, and the constant temperature heating device is used to control the temperature of the barrel of the extrusion puffing machine according to different materials to be extracted.

10. A supercritical carbon dioxide extraction and separation method based on extrusion expansion, based on a supercritical carbon dioxide extraction and separation system based on extrusion expansion according to any one of claims 1 to 9, characterized in that: include: The material to be extracted is expanded in the extrusion puffing machine through mechanical actions such as extrusion, kneading, shearing and pressurization, as well as the auxiliary action of supercritical carbon dioxide; The expanded material enters the pre-preg tank, and the penetration and dissolution effect of supercritical carbon dioxide is used to dissolve the effective components in the cell structure of the material in advance; The prepreg is fed tangentially into the extraction kettle through the jet feeding subsystem for fluidized continuous extraction. The supercritical carbon dioxide carrying the solute flows out from the overflow port at the top of the extraction kettle and re-enters the extraction kettle through the circulation pump. When the supercritical carbon dioxide in the kettle is saturated or nearly saturated, the saturated carbon dioxide is discharged into the extract pressure reduction and separation subsystem, and fresh carbon dioxide is introduced; the extraction process is repeated until the prepreg is completely extracted. Finally, the saturated carbon dioxide carrying the solute is discharged from the overflow port of the extraction kettle into the extract pressure reduction and separation subsystem. After two pressure reduction separations, the extract is precipitated and collected, and the carbon dioxide is collected and recycled. After the extract is completely separated, the carbon dioxide fluid carrying the residue flows into the residue separation subsystem through the twenty-second stop valve to separate the residue from the carbon dioxide, collect the residue, and collect and recycle the carbon dioxide.

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