A filtration device for supercritical extraction

Abstract

This utility model relates to the field of oil extraction technology and discloses a filtration device for supercritical fluid extraction, including an extraction vessel, an extractant inlet pipe, and an extractant outlet pipe, both of which are connected to the extraction vessel. It also includes a filtration device comprising a semi-permeable filter layer, a macroporous layer, and a precision filter layer. The semi-permeable filter layer has several through holes; the macroporous layer has large pores connecting the through holes and the precision filter layer; and the precision filter layer has several small pores connecting the macroporous layer to the downstream side of the device. This utility model aims to solve the problem that the outlet pipe often becomes clogged when the extractant flows through the extraction vessel, especially when the material cake or filter cake is thick, resulting in easy entry but difficult exit of the extractant and low extraction efficiency.

Description

Technical Field

[0001] This utility model relates to the field of oil extraction technology, specifically to a filtration device for supercritical extraction. Background Technology

[0002] Supercritical fluids are a special fluid state that a substance exhibits when it is above its critical temperature and critical pressure. In this state, pressurizing the gas will not cause it to liquefy; instead, it will only increase in density, possessing properties similar to both liquids and gases. Specifically, supercritical fluids have a density close to that of liquids, thus exhibiting strong dissolving power; their viscosity is similar to that of gases, and their diffusion coefficient is much greater than that of ordinary liquids, giving them a significant advantage in mass transfer processes. Furthermore, supercritical fluids have zero surface tension, allowing them to easily penetrate and diffuse into the microporous structure of the extractant, thus possessing excellent dissolving and mass transfer characteristics. They can quickly reach mass transfer equilibrium with the extractant, achieving highly efficient separation of substances.

[0003] Supercritical fluid extraction (CFDE) technology, with its advantages of being environmentally friendly, low-cost, and easy to implement, is considered one of the important future development directions in the field of oil extraction. Existing literature reports and the practices of some oil production enterprises indicate that this technology has been initially applied to the production of high-end oils. However, since its inception decades ago, its large-scale industrial application still faces many limitations. The main problems are the high cost of supercritical fluid extraction equipment, low production efficiency, and high energy consumption, resulting in high overall production costs and making it difficult to achieve large-scale promotion.

[0004] Patent 201410030959X proposes an improved solution: by allowing the extractant to flow from top to bottom through the extraction vessel or extraction tank, both extraction and pressing effects are simultaneously achieved, thereby significantly improving extraction efficiency. However, this technology still has drawbacks in practical applications: when the extractant flows through the extraction vessel or tank, the outlet pipe is prone to blockage due to the thickening of the filter cake layer, hindering the flow of the extractant and thus reducing extraction efficiency. Utility Model Content

[0005] To address existing problems, this utility model aims to provide a filtration device for supercritical extraction. It addresses the issue of frequent blockages in the outlet pipe when the extractant flows through the extraction vessel, particularly when the material cake or filter cake is thick, resulting in easy entry but difficult exit and low extraction efficiency. By setting a semi-permeable filter layer, the pressure difference between the macroporous layer and the material basket is accumulated and released, facilitating the expansion of the packing material through the pressure difference of the semi-permeable filter layer. This ensures efficient extraction or filtration of the raw material in the vessel by the supercritical extractant.

[0006] To achieve the above objectives, the present invention provides the following technical solution.

[0007] This utility model provides a filtration device for supercritical extraction, including an extraction vessel, an extractant inflow pipe, and an extractant outflow pipe, both of which are connected to the extraction vessel. The extraction filtration device also includes a filtration device; the filtration device sequentially includes a semi-permeable filter layer, a macroporous layer, and a precision filter layer, wherein the semi-permeable filter layer is provided with a plurality of through holes; the macroporous layer is provided with macropores, which connect the through holes and the precision filter layer; the precision filter layer is provided with a plurality of small holes, which connect the macroporous layer and the downstream of the device.

[0008] As a further improvement of this utility model, the pressure difference between the macroporous layer and the basket is sufficient to cause the pressure difference to expand when the material passes through the through hole.

[0009] As a further improvement of this utility model, the diameter of the through hole is 0.1mm-20mm.

[0010] As a further improvement of this utility model, the minimum diameter of the large hole is 0.1 mm, and the maximum diameter is the inner diameter of the extraction vessel.

[0011] As a further improvement of this utility model, the filtration device is located downstream of the extractant outlet pipeline.

[0012] As a further improvement of this utility model, it also includes a material basket and a sealing component disposed inside the extraction vessel.

[0013] As a further improvement of this utility model, the perforated layer is composed of multiple layers stacked together.

[0014] As a further improvement of this utility model, the sealing component is disposed between the material basket and the inner wall of the extraction vessel or between the filter device and the extraction vessel.

[0015] As a further improvement of this utility model, the sealing component is made of polytetrafluoroethylene and its modified forms.

[0016] As a further improvement of this utility model, both the upper and lower ends of the basket are made of metal woven mesh.

[0017] This utility model has the following beneficial effects: This invention utilizes a multi-layered filtration structure (semi-permeable filter layer, macroporous layer, and precision filter layer) to achieve the accumulation and release circulation of pressure difference between the macroporous layer and the material basket during supercritical extraction, or the accumulation and release circulation of pressure difference between the extractant outlet pipeline and the downstream of the device during supercritical filtration. This facilitates the expansion of materials in the extraction vessel through the pressure difference of the semi-permeable filter layer, improving filtration efficiency and extract purity. When the compacted pulverized raw material comes into contact with the surface of the semi-permeable filter layer, the material at the through-holes processed on the semi-permeable filter layer sinks into the through-holes under the push of the extractant, while the material at the unprocessed through-holes is blocked in situ by the surface of the semi-permeable filter layer. This invention disrupts the contact surface of the semi-permeable filter layer with the raw material, preventing the formation of a dense filter layer. The macroporous layer promotes the depressurization and expansion of the raw material passing through the through-holes in the sealed chamber, achieving full contact with the extractant. The precision filter layer ultimately intercepts residues, ensuring that pure extract flows out of the extractant outlet pipeline and improving extraction efficiency. This invention mainly addresses the problems of material compaction and clogging in existing supercritical equipment and the free flow of extractant through the extraction vessel or extraction tank. It provides a large-scale supercritical extraction filtration device with a reasonable design, convenient extractant inlet and outlet, simple structure, high extraction efficiency, and simple operation, which can be widely applied in the field of large-scale supercritical extraction.

[0018] Preferably, the pressure difference causes the extract to expand as it passes through the through-hole, increasing the contact area between the extract and the extractant, significantly improving the extraction efficiency, and also facilitating the release of the active ingredients in the extract.

[0019] Preferably, the pore size range of the through holes is specified, which ensures that the mixture of different types of crushed raw materials (such as walnut pulp, peanut residue and camellia seed residue) and supercritical solvent can partially pass through the semi-permeable filter layer, while avoiding the decrease in filtration effect due to excessively large pore size or the blockage caused by excessively small pore size, thus optimizing the performance of the filtration device.

[0020] Preferably, the pore size range of the macropores ensures that the macroporous layer can accommodate a sufficient volume of extract to achieve the expansion effect, and can also effectively connect with the precision filter layer to prevent extract residue from directly entering the extractant outlet pipeline, thereby improving the reliability of filtration.

[0021] Preferably, a filtration device is installed downstream of the extraction vessel's outlet pipeline. This device further filters the fluid flowing out of the extractant outlet pipeline after extraction, effectively intercepting any solid impurities or incompletely extracted particulate matter, thereby obtaining a purer extract and improving product quality. The filtration device also prevents impurities in the extractant outlet pipeline from entering subsequent pipes, storage devices, or other processing equipment. This achieves in-vessel extraction and out-of-vessel filtration, and facilitates disassembly and maintenance. It avoids these impurities causing wear, blockage, or other damage to subsequent equipment, extending the service life of subsequent equipment and reducing equipment maintenance costs and failure rates.

[0022] Preferably, in conjunction with the structure of the filtration device, the material basket works in conjunction with the semi-permeable filter layer. The material basket provides an initial accumulation and action area for the raw material, ensuring that the raw material maintains a relatively fixed position within the extraction vessel, preventing random dispersion. Furthermore, the material basket allows the raw material to gradually enter the subsequent filtration and extraction stages under the influence of pressure difference, promoting sufficient contact and material exchange between the extractant and the raw material. The sealing component is located between the material basket and the inner wall of the extraction vessel, or between the filtration device and the extraction vessel, and its main function is to ensure the airtightness of the entire extraction system. Supercritical extraction is typically carried out under high pressure. If a leak occurs in the system, the supercritical substance (extractant) will escape, not only wasting the extractant and increasing production costs but also potentially polluting the environment. Simultaneously, leakage can also lead to unstable pressure within the extraction vessel, affecting extraction efficiency and product quality.

[0023] Prior to this, the multi-layered, stacked pore layer enhances filtration precision and interception capacity, effectively preventing tiny residues from penetrating the filter layer, further improving the purity of the extract, and extending the service life of the filtration device.

[0024] Prior to this, the sealing components prevent leakage of supercritical substances at pressures up to 30 MPa, ensuring that the extraction process takes place in a closed environment, improving production safety, and avoiding waste of extractant and environmental pollution.

[0025] Preferably, polytetrafluoroethylene (PTFE) and its modified forms possess excellent chemical stability and low surface energy, effectively preventing leakage of the medium (such as supercritical fluid) during supercritical extraction and ensuring stable internal pressure of the device. During supercritical extraction, PTFE and its modified forms exhibit strong resistance to most chemicals, including supercritical carbon dioxide, and are not easily corroded, thus ensuring the performance stability of sealing components during long-term use and reducing the risk of leakage and equipment downtime due to damage to sealing components. Furthermore, during supercritical extraction, the internal temperature environment of the device may be high, and PTFE and its modified forms possess good high-temperature resistance.

[0026] Preferably, the metal woven mesh at the upper and lower ends of the basket has a uniform porous structure, allowing the supercritical fluid to pass freely through these pores and fully contact the raw material inside the basket. This good permeability makes the flow of the supercritical fluid in the basket smoother, forming a uniform fluid extraction, improving the efficiency of mass transfer during the extraction process, and enabling the extractant to dissolve and extract the target components in the raw material more quickly and fully, thereby shortening the extraction time and improving the extraction efficiency. The porous structure of the metal woven mesh allows the entire stream of extractant flowing into the extraction vessel to be divided into multiple fine streams, avoiding impact on the surface of the raw material inside the basket. Attached Figure Description

[0027] The accompanying drawings described herein are for illustrative purposes only and do not limit the scope of this invention in any way. Furthermore, the shapes and proportions of the components in the drawings are merely schematic to aid in understanding the invention and do not specifically limit the shapes and proportions of the components. In the drawings: Figure 1 This is a schematic diagram of the structure of the supercritical extraction filtration device in Example 1 when a material basket is used inside the vessel; Figure 2 This is a top view of the semi-permeable filter layer structure of the supercritical extraction and filtration device in Example 1; Figure 3 This is a cross-sectional schematic diagram of the three-layer structure of the supercritical extraction filtration device in Example 1; Figure 4 This is a schematic diagram of the supercritical extraction and filtration device in Example 2; Figure 5 This is a schematic diagram of the supercritical extraction and filtration device in Example 3; Figure 6 This is a schematic diagram of the supercritical extraction and filtration device in Example 4; Figure 7 This is a schematic diagram of the supercritical extraction and filtration device in Example 5; Figure 8 This is a schematic diagram of the supercritical extraction and filtration device in Example 6; Figure 9 This is a schematic diagram of the supercritical extraction and filtration device in Example 7; Figure 10 This is a schematic diagram of the structure of the supercritical extraction filtration device used outside the reactor in Example 8; The components include: 1. Semi-permeable filter layer; 2. Macroporous layer; 3. Precision filter layer; 4. Filtering device; 5. Extraction vessel; 6. Extractant inflow pipeline; 7. Extractant outflow pipeline; 8. Basket; 9. Sealing component; 10. Crushed raw material; 11. Top cover; 12. Bottom cover. Detailed Implementation

[0028] To enable those skilled in the art to better understand the technical solutions of this utility model, the technical solutions of the embodiments of this utility model will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of this utility model, and not all embodiments. Based on the embodiments of this utility model, all other embodiments obtained by those skilled in the art without creative effort should fall within the protection scope of this utility model.

[0029] It should be noted that when an element is referred to as being "set on" another element, it can be directly on the other element or there may be an intervening element. When an element is stated to be "connected to" another element, it can be directly connected to the other element or there may be an intervening element. The terms "vertical," "horizontal," "left," "right," and similar expressions used herein are for illustrative purposes only and do not represent the only embodiments.

[0030] Unless otherwise defined, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this invention pertains. The terminology used herein is for the purpose of describing particular embodiments only and is not intended to be limiting of the invention. The term "and / or" as used herein includes any and all combinations of one or more of the associated listed items.

[0031] Example 1 like Figure 1 As shown, this embodiment provides a filtration device for supercritical extraction, including an extraction vessel 5, an extractant inlet pipe 6, and an extractant outlet pipe 7. The extractant inlet pipe 6 is located on the upper side of the extraction vessel 5, and the extractant outlet pipe 7 is located at the bottom of the extraction vessel 5. Both the extractant inlet pipe 6 and the extractant outlet pipe 7 are connected to the extraction vessel 5. A material basket 8, a filtration device 4, and a sealing component 9 are provided inside the extraction vessel 5. Figure 2 As shown, the upper surface of the filter device 4 is machined with several through holes; for example... Figure 3 As shown, the filtration device 4 includes a semi-permeable filter layer 1, a macroporous layer 2, and a precision filter layer 3 in sequence. The layers can be stacked, or connected by connectors, sealed by welding, or integrally cast.

[0032] Specifically, such as Figure 3As shown, the semi-permeable filter layer 1 includes an upper surface and a lower surface, both of which can be planar, concave, or other inclined shapes; the cross-section of the semi-permeable filter layer 1 perpendicular to the extractant flow direction can be circular, triangular, rhomboid, rectangular, or other shapes; the semi-permeable filter layer 1 is provided with a plurality of through holes, which can be circular, triangular, rhomboid, rectangular, or other shapes, and the through holes connect the material basket 8 and the macroporous layer 2; the macroporous layer 2 is provided with large holes, which connect the macroporous layer 2 and the precision filter layer 3; the precision filter layer 3 is provided with a plurality of small holes, which connect the macroporous layer 2 and the extractant outflow pipe 7 (i.e., the filter device 4 is located inside the extraction vessel 5) or the downstream device outside the extraction vessel 5 (i.e., the filter device 4 is located outside the extraction vessel 5). Specifically, because of the supercritical extractant, the internal pressure of the basket 8 can reach 30 MPa, while the internal pressure can be reduced to 7 MPa after passing through the extraction and filtration device 4 downstream of the device. Therefore, another extraction and filtration device 4 can be installed downstream of the device to enable the extract to undergo a similar extraction process again.

[0033] Specifically, the pressure difference between the macroporous layer 2 and the material in the basket 8 is sufficient to cause the pressure difference to expand when the material passes through the through hole.

[0034] Specifically, the diameter of the through hole is 0.1mm-20mm.

[0035] Specifically, the minimum diameter of the large pore is 0.1 mm, and the maximum diameter is the inner diameter of the extraction vessel 5.

[0036] The aperture of the small hole allows the extract to flow out of the extractant outlet pipe 7 and allows the residue of the extract to be intercepted by the filter device 4.

[0037] Optionally, the porous layer is composed of multiple layers stacked together.

[0038] The sealing component 9 is disposed between the material basket 8 and the extraction vessel 5 or between the filter device 4 and the extraction vessel 5.

[0039] like Figure 1 As shown, the working principle of the extraction and filtration device in Example 1 is as follows: the extractant enters the extraction vessel 5 from the top side. A sealing component 9 is provided between the extraction vessel 5 and the material basket 8. The sealing component 9 guides the extractant to enter the material basket 8 from the top, pass through the crushed raw material 10, and then pass through the semi-permeable filter layer 1, the macroporous layer 2 and the precision filter layer 3 of the filtration device 4 in sequence. The extractant flows out of the material basket 8 from the bottom and then flows out of the extraction vessel 5 from the bottom pipe.

[0040] The operating principle of a supercritical fluid extraction filtration device in this embodiment is as follows: According to the direction of extractant flow, filter device 4 is set on the side of extractant outlet pipe 7 of extraction vessel 5, and crushed and compacted raw material is loaded at the front end of filter device 4. The high-pressure extractant entering the extraction vessel 5 flows sequentially through the raw material layer, the semi-permeable filter layer 1, the macroporous layer 2, and the precision filter layer 3, and finally flows out of the extraction vessel 5.

[0041] Specifically, the high-pressure extractant entering the extraction vessel 5 flows sequentially through the raw material layer, the semi-permeable filter layer 1, the macroporous layer 2, and the precision filter layer 3, and finally flows out of the extraction vessel 5, including the following steps: the pulverized raw material 10 in the extraction vessel 5 is intercepted by the semi-permeable filter layer 1 of the filter device 4 under the push of the high-pressure extractant, the flow of the extractant is obstructed, and a pressure difference is generated between the upper and lower parts of the filter device 4. Then, under the gradually increasing pressure difference, the pulverized raw material 10 enters the through holes and macroporous layer 2 of the semi-permeable filter layer 1 by the local depression of the contact surface, while the extractant flows into the semi-permeable filter layer 5. Through the through holes of the filter layer 1 and the macroporous layer 2, the continuous inflow of extractant causes the pressure difference between the upper and lower parts of the filter device to gradually disappear. The pulverized raw material 10 in the extraction vessel 5 is once again intercepted by the semi-permeable filter layer 1 of the filter device 4 under the push of the high-pressure extractant. The flow of extractant is obstructed, and a pressure difference is generated between the upper and lower parts of the filter device 4. The above process is repeated. The pulverized raw material 10 penetrates through the through holes of the semi-permeable filter layer 1 and enters the macroporous layer 2. The pulverized raw material 10 changes from a compact state to a relatively loose state. The extractant extracts the raw material in the relatively loose state in the macroporous layer 2.

[0042] Example 2 The difference between this embodiment and Embodiment 1 is that: 1) The filter device 4 is located outside the material basket 8.

[0043] The filter device 4 is located outside the material basket 8. The filter device 4 and the material basket 8 are independent of each other, which makes it easy to remove the material basket 8 separately after completing a raw material filling and extraction operation, and to refill the material basket 8 with new raw materials, saving time and procedures. If the type of raw material is changed, the material basket 8 and the filter device 4 need to be removed and cleaned.

[0044] like Figure 4 As shown, the working principle of the extraction and filtration device in Example 2 is as follows: the extractant enters the extraction vessel 5 from the top side. A sealing component 9 is provided between the extraction vessel 5 and the material basket 8. The sealing component 9 guides the extractant to enter the material basket 8 from the top, pass through the crushed raw material 10, flow out of the material basket 8 from the bottom, and then pass through the semi-permeable filter layer 1, the macroporous layer 2 and the precision filter layer 3 of the filtration device 4 in sequence, and then flow out of the extraction vessel 5 from the bottom pipe.

[0045] Example 3 The difference between this embodiment and Embodiment 1 is that: 1) The extractant inlet pipe 6 is located at the bottom of the extraction vessel 5, and the extractant outlet pipe 7 is located at the top side of the extraction vessel 5.

[0046] The extractant outlet pipe 7 is located on the top side of the extraction vessel 5, which changes the flow direction of the fluid. This change may cause some turbulence and pressure fluctuations inside the fluid, but the fluid is less affected by factors such as gravity as it flows to the side.

[0047] The extractant inlet pipe 6 is located at the bottom of the extraction vessel 5, and the extractant outlet pipe 7 is located at the top or top side of the extraction vessel 5. This extractant flow direction is opposite to the gravity direction of the raw material, which can make the extractant and the raw material more fully contacted and improve the extraction efficiency to a certain extent. However, at the same time, it will require the extractant inlet pipe 6 to provide greater internal pressure, which will increase energy consumption to a certain extent.

[0048] like Figure 5 As shown, the working principle of the extraction and filtration device in Example 3 is as follows: the extractant enters the extraction vessel 5 from the bottom. A sealing component 9 is provided between the extraction vessel 5 and the material basket 8. The sealing component 9 guides the extractant to enter the material basket 8 from the bottom, pass through the crushed raw material 10, and then pass through the semi-permeable filter layer 1, the macroporous layer 2 and the precision filter layer 3 of the filtration device 4 in sequence. The extractant flows out of the material basket 8 from the bottom of the red material and then flows out of the extraction vessel 5 from the side pipe.

[0049] Example 4 The difference between this embodiment and Embodiment 1 is that: 1) The extraction vessel 5 also includes an upper top cover 11 and a lower bottom cover 12, and the material basket 8 is replaced by the upper top cover 11 and the lower bottom cover 12; 2) The material basket 8 and the sealing component 9 are omitted.

[0050] The design of the top cover 11 and bottom cover 12 of the extraction vessel 5 facilitates the opening, closing, and disassembly of the extraction vessel 5. The top cover 11 and bottom cover 12 typically employ quick-opening structures, such as toothed quick-opening sealing devices or clamp-type quick-opening sealing devices, enabling operators to quickly and easily open and close the extraction vessel 5, improving production efficiency. During intermittent extraction operations, the design of the top cover 11 and bottom cover 12 makes material replacement more convenient, reducing operation time. The elimination of the material basket 8 and sealing components 9 reduces equipment procurement and maintenance costs. By omitting the material basket 8, the original material can be directly... The material is poured into the extraction vessel 5, which simplifies the loading and unloading process, reducing operation time and labor intensity. By eliminating the material basket 8, the effective volume of the extraction vessel 5 increases, allowing more raw material to be loaded into the same volume of extraction vessel 5, thus improving equipment utilization and production capacity. Without the obstruction of the material basket 8, the flow of supercritical fluid in the extraction vessel 5 is smoother, enabling more uniform contact with the raw material, which is beneficial to improving extraction efficiency and extraction quality. However, the disadvantage of not using the material basket 8 is that the raw material may not be evenly distributed in the extraction vessel 5, resulting in insufficient contact between the supercritical fluid and the raw material.

[0051] like Figure 6 As shown, the working principle of the extraction and filtration device in Example 4 is as follows: During loading, close the bottom cover 12, place the filter device 4 at the bottom of the extraction vessel 5, fill the upper part of the filter device 4 with raw material, and then cover it with the top cover 11. Alternatively, during loading, place the filter device 4 on the bottom cover 12 and install it together with the bottom cover 12 on the extraction vessel 5, then fill the upper part of the filter device 4 with raw material, and then cover it with the top cover 11. The extractant enters the vessel from the top side, passes through the crushed raw material 10, and then passes through the semi-permeable filter layer 1, the macroporous layer 2, and the precision filter layer 3 of the filter device 4 in sequence, and flows out of the extraction vessel 5 from the side pipe. During unloading, open the top cover 11 and the bottom cover 12, and remove the residue and filter device 4 from the vessel.

[0052] Example 5 The difference between this embodiment and embodiment 4 is that: 1) The extractant inlet pipe 6 is located at the bottom side of the extraction vessel 5, and the extractant outlet pipe 7 is located at the top side of the extraction vessel 5.

[0053] like Figure 7 As shown, the working principle of the extraction and filtration device in Example 5 is as follows: During loading, the lower bottom cover 12 is closed, raw materials are loaded into the extraction vessel 5, the filter device 4 is placed on top of the raw materials in the extraction vessel 5, and then the upper top cover 11 is closed. Alternatively, during loading, the lower bottom cover 12 is closed, raw materials are loaded into the extraction vessel 5, the filter device 4 is fixed under the upper top cover 11, and installed on the extraction vessel 5 together with the upper top cover 11, and then the upper top cover 11 is closed. The extractant enters the vessel from the bottom of the extraction vessel 5, passes through the crushed raw material 10, and then passes through the semi-permeable filter layer 1, the macroporous layer 2, and the precision filter layer 3 of the filter device 4 in sequence, and flows out of the extraction vessel 5 from the pipe at the top of the extraction vessel 5. During unloading, the upper top cover 11 and the lower bottom cover 12 are opened, and the residue and filter device 4 in the vessel are removed.

[0054] Example 6 The difference between this embodiment and embodiment 5 is as follows: 1) The extractant inlet pipe 6 is located at the bottom of the extraction vessel 5, or the extractant outlet pipe 7 is located at the top of the extraction vessel 5.

[0055] like Figure 8As shown, the working principle of the extraction and filtration device in Example 6 is as follows: During loading, the lower bottom cover 12 is closed, raw materials are loaded into the extraction vessel 5, the filter device 4 is placed on top of the raw materials in the extraction vessel 5, and then the upper top cover 11 is closed. Alternatively, during loading, the lower bottom cover 12 is closed, raw materials are loaded into the extraction vessel 5, the filter device 4 is fixed under the upper top cover 11, and installed on the extraction vessel 5 together with the upper top cover 11, and then the upper top cover 11 is closed. The extractant enters the vessel from the bottom of the extraction vessel 5, passes through the crushed raw material 10, and then passes through the semi-permeable filter layer 1, the macroporous layer 2, and the precision filter layer 3 of the filter device 4 in sequence, and flows out of the extraction vessel 5 from the pipe at the top of the extraction vessel 5. During unloading, the upper top cover 11 and the lower bottom cover 12 are opened, and the residue and filter device 4 in the vessel are removed.

[0056] Example 7 The difference between this embodiment and embodiment 6 is that: 1) The extractant inlet pipe 6 is located at the top of the extraction vessel 5, or the extractant outlet pipe 7 is located at the bottom of the extraction vessel 5.

[0057] like Figure 9 As shown, the working principle of the extraction and filtration device in Example 7 is as follows: During loading, the lower bottom cover 12 is closed, the filter device 4 is placed at the bottom of the extraction vessel 5, and the raw material is loaded into the extraction vessel 5, compacting it onto the filter device 4. Then, the upper top cover 11 is closed. Alternatively, during loading, the filter device 4 is fixed to the lower bottom cover 12, the lower bottom cover 12 is closed, the raw material is loaded into the extraction vessel 5, compacting it onto the filter device 4, and then the upper top cover 11 is closed. The extractant enters the vessel from the top of the extraction vessel 5, passes through the crushed raw material 10, and then sequentially passes through the semi-permeable filter layer 1, the macroporous layer 2, and the precision filter layer 3 of the filter device 4, flowing out of the extraction vessel 5 through the pipe of the lower bottom cover 12. During unloading, the upper top cover 11 and the lower bottom cover 12 are opened, and the residue and filter device 4 are removed from the vessel.

[0058] Example 8 like Figure 10 As shown, the working principle of the extraction and filtration device in Example 8 is as follows: The extraction vessel 5 is filled with raw material (if there is a basket 8, the raw material is placed inside the basket 8, and the basket 8 is placed inside the extraction vessel 5; if there is no basket 8, the raw material is directly placed inside the extraction vessel 5). The filtration device 4 is located downstream of the extractant outlet pipe 7. The raw material inside the extraction vessel 5 is partially carried to the filtration device 4 outside the extraction vessel 5 by the flow direction of the extractant. The extractant passes through the semi-permeable filter layer 1, the macroporous layer 2, and the precision filter layer 3 of the filtration device 4 in sequence before entering the subsequent stages. Solid raw material particles carried out of the extraction vessel 5 are retained by the filtration device 4. This achieves extraction inside the extraction vessel 5 and filtration outside the extraction vessel 5. After extraction, the extraction vessel 5 is opened, and the residue inside is removed; the outer shell of the filtration device 4 is opened, allowing for convenient cleaning of the filtration device 4 from the outside.

[0059] The features of this utility model are summarized as follows: Raw material loading stage: According to the direction of extractant flow, the filter device 4 needs to be set in the direction of extractant outflow inside the extraction vessel 5, and the crushed raw material is loaded at the front end of the filter device 4 so as to achieve efficient filtration of the extractant outflow pipeline 7 during the extraction process.

[0060] Pressure extraction stage: The high-pressure extractant entering the extraction vessel 5 flows sequentially through the raw material layer, the semi-permeable filter layer 1, the macroporous layer 2 and the precision filter layer 3 of the filter device 4, and then flows out of the extraction vessel 5. The filtration device 4 performs a highly efficient filtration process as follows: The compacted raw material 10 in the extraction vessel 5 is pushed by the high pressure difference of the high-pressure extractant and enters the through-hole of the semi-permeable filter layer 1 by the local sinking of the contact surface. At this time, the contact surface of the compacted raw material is destroyed due to the local sinking, and a large amount of extractant flows into the through-hole of the semi-permeable filter layer 1. The pressure difference gradually disappears, and the compacted raw material layer forms a new contact surface. Through the alternation of the formation and destruction of the pressure difference, the upstream solid raw material layer can be partially blocked, preventing it from continuously entering the macroporous layer 2 and the downstream precision filter layer 3. The compacted raw material that penetrates the semi-permeable filter layer 1 enters the macroporous layer 2. Due to the large space of the macroporous layer 2, the high pressure environment of the compacted raw material that penetrates the semi-permeable filter layer 1 by the pressure difference is broken, and the raw material changes from a compacted state to a relatively loose state again. The extractant can easily pass through the relatively loose raw material, achieving efficient flow and extraction of the extractant. The relatively loose raw material is blocked by the precision filter layer 3 and is retained in the macroporous layer 2, where it is efficiently extracted by the extractant flowing through the macroporous layer 2. Therefore, the filtration device 4 is a continuous and efficient filtration process that relies on pressure difference to destroy the dense structure formed at the contact surface between the raw material and the semi-permeable filter layer 1. As the extractant flows, the pressure difference gradually disappears, and the contact surface reforms into a dense structure, which in turn creates a pressure difference again. The pressure difference then destroys the dense structure at the contact surface once more.

[0061] This invention provides a novel supercritical fluid extraction filtration device that can be configured for both top-in / bottom-out and bottom-in / top-out processes. It combines the advantages of traditional bottom-in / top-out production processes with the novel top-in / bottom-out process, eliminating concerns for enterprises and promoting technological advancement. The extraction filtration device utilizes a pressure differential to disrupt the dense structure formed at the contact surface between the raw material and the semi-permeable filter layer 1. As the extractant flows, the pressure differential gradually disappears, and the contact surface reforms into a dense structure, creating a new pressure differential. This renewed pressure differential disrupts the dense structure at the contact surface, achieving a continuous and efficient filtration process, thus improving production efficiency.

[0062] The above embodiments are merely one of the implementation methods to achieve the technical solution of this utility model. The scope of protection claimed by this utility model is not limited to this embodiment, but also includes any variations, substitutions and other implementation methods that can be easily conceived by those skilled in the art within the scope of the technology disclosed in this utility model.

Claims

1. A filtration device for supercritical extraction, comprising an extraction vessel (5), an extractant inlet pipe (6), and an extractant outlet pipe (7), wherein both the extractant inlet pipe (6) and the extractant outlet pipe (7) are connected to the extraction vessel (5), characterized in that, The device includes a filter (4); the filter (4) includes a semi-permeable filter layer (1), a macroporous layer (2) and a precision filter layer (3) in sequence. The semi-permeable filter layer (1) is provided with a plurality of through holes; the macroporous layer (2) is provided with macropores, which are connected to the through holes and the precision filter layer (3); the precision filter layer (3) is provided with a plurality of small holes, which are connected to the macroporous layer (2) and the downstream of the device.

2. The filtration device for supercritical extraction according to claim 1, characterized in that, The pressure difference between the macroporous layer (2) and the basket (8) is sufficient to cause the material to expand under pressure when passing through the through hole.

3. The filtration device for supercritical extraction according to claim 1, characterized in that, The diameter of the through hole is 0.1mm-20mm.

4. The filtration device for supercritical extraction according to claim 1, characterized in that, The minimum diameter of the large pore is 0.1 mm, and the maximum diameter is the inner diameter of the extraction vessel (5).

5. The filtration device for supercritical extraction according to claim 4, characterized in that, The filter device (4) is located downstream of the extractant outlet pipe (7).

6. The filtration device for supercritical extraction according to claim 1, characterized in that, It also includes a material basket (8) and a sealing component (9) installed inside the extraction vessel (5).

7. The filtration device for supercritical extraction according to claim 1, characterized in that, The porous layer is composed of multiple layers stacked together.

8. The filtration device for supercritical extraction according to claim 6, characterized in that, The sealing component (9) is disposed between the material basket (8) and the inner wall of the extraction vessel (5) or between the filter device (4) and the inner wall of the extraction vessel (5).

9. A filtration device for supercritical extraction according to claim 6, characterized in that, The sealing component (9) is made of polytetrafluoroethylene and its modified forms.

10. A filtration device for supercritical extraction according to claim 6, characterized in that, The upper and lower ends of the basket (8) are made of metal woven mesh.

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