Extraction device for residual oil and tea saponins in camellia seed cake

Abstract

This invention provides a device for extracting residual oil and tea saponins from camellia seed cake, belonging to the field of camellia seed cake processing technology. The extraction device includes an extraction tank, a liquid collection tube, an upper electrode plate, and a lower electrode plate. When the liquid collection tube drives the upper electrode plate downward within the extraction tank, it can compress the raw material and generate high pressure. After the upper and lower electrode plates are energized, ohmic heat is generated inside the raw material. The high temperature and high pressure environment puts the water in the raw material into a subcritical state. Subcritical water can better dissolve and extract residual oil and tea saponins. This device adopts ohmic heating, which is not limited by heat transfer area and temperature difference, has a high heating rate and high thermal efficiency, and does not require an external heat exchanger or high-pressure conveying system. In addition, this device can compress the material by driving the porous upper electrode plate through the liquid collection tube, and simultaneously perform solid-liquid separation under subcritical temperature and pressure, preventing the extract from returning to the solid phase.

Description

Technical Field

[0001] This invention belongs to the field of camellia seed cake processing technology, and more specifically, relates to a device for extracting residual oil and tea saponins from camellia seed cake. Background Technology

[0002] Currently, my country's annual camellia seed production exceeds 4.2 million tons, and the camellia cake yield after pressing reaches more than 3 million tons. The residual oil, tea saponins, proteins, polysaccharides and other macro-components in the camellia cake have high utilization value. If they are not utilized, it will result in a huge waste of resources.

[0003] Currently, industrial extraction of residual oil and tea saponins from camellia seed cake mostly employs a stepwise extraction process, that is, first extracting the residual oil and then extracting the tea saponins. Commonly used processes include: hydrocarbon-alcohol two-stage extraction, extracting oil and tea saponins separately; and hydrocarbon-water two-stage extraction, extracting oil and tea saponins separately. However, these methods involve the use of flammable and explosive organic solvents, are complex, and lack safety and environmental friendliness. Given the properties of subcritical water, continuous extraction from water-soluble to fat-soluble substances can be achieved, potentially enabling the simultaneous extraction of residual oil and tea saponins from camellia seed cake.

[0004] Subcritical water extraction requires high temperature and high pressure. Existing devices have three major limitations: (1) The heating method is mainly indirect heating, which is limited by the heat exchange area and temperature difference of the tank, resulting in low heat transfer efficiency and slow heating rate. Direct heating with subcritical water requires an external heat exchanger, high-pressure pump and pipeline system, which greatly increases the complexity of the device. (2) Due to the sealing requirements of the high-pressure tank, only magnetic stirring or no stirring can be used, which makes it difficult to improve the heat and mass transfer efficiency of the extraction operation, resulting in poor material temperature uniformity and insufficient extraction of target components. (3) The tank can only meet the basic requirements for extracting target components. After extraction, an external separation device is needed to achieve solid-liquid separation, so solid-liquid separation under subcritical conditions cannot be achieved. Summary of the Invention

[0005] The purpose of this invention is to provide an extraction device for residual oil and tea saponins in camellia seed cake, which solves the problems of low heating efficiency, complex structure and inability to achieve solid-liquid separation simultaneously in existing extraction devices.

[0006] To achieve the above objectives, the present invention provides an apparatus for extracting residual oil and tea saponins from camellia seed cake, comprising:

[0007] An extraction tank, wherein the extraction tank is an insulated cylinder and has a feed inlet at the top;

[0008] A liquid collection tube, the lower end of which is movably inserted into the top of the extraction tank, and the upper end of which extends outside the extraction tank and is provided with an extract liquid discharge valve.

[0009] The upper electrode plate has an outer periphery that mates with the inner periphery of the extraction tank. The upper electrode plate is connected to one end of the liquid collection tube. The upper electrode plate has mesh holes to allow the extraction tank to communicate with the liquid collection tube.

[0010] The lower electrode plate is disposed above the bottom of the extraction tank.

[0011] Optionally, the lower electrode plate includes:

[0012] An insulating porous mesh plate, the outer periphery of which is connected to the inner periphery of the extraction tank;

[0013] A circular conductive sheet, the diameter of which is smaller than the inner diameter of the extraction vessel, is centrally located on the lower surface of the insulating porous mesh plate.

[0014] Optionally, the bottom of the extraction tank is provided with a discharge valve, which can be opened or closed, and the lower electrode plate is disposed on the discharge valve.

[0015] Optionally, the device for extracting residual oil and tea saponins from camellia seed cake further includes:

[0016] A driving device is connected to the liquid collection tube and is used to drive the liquid collection tube to move up and down.

[0017] Optionally, the top of the extraction tank is provided with a threaded sealing section, and the liquid collection tube is threadedly connected to the threaded sealing section. The driving device can drive the liquid collection tube to rotate so that the liquid collection tube moves up and down.

[0018] Optionally, the liquid collection tube is connected to the upper electrode plate via a connecting section that gradually narrows from bottom to top.

[0019] Optionally, the aperture of the mesh is no greater than 0.38 mm.

[0020] Optionally, the liquid collection tube is provided with a conductive slip ring, which is connected to the upper electrode plate 4.

[0021] Optionally, the number of teeth in the threaded sealing section is not less than 16.

[0022] Optionally, a sealing ring is provided at the edge of the upper electrode plate.

[0023] The beneficial effects of this invention are as follows: It provides an extraction device for residual oil and tea saponin from camellia seed cake, comprising: an extraction tank, a liquid collection tube, an upper electrode plate, and a lower electrode plate. When the liquid collection tube drives the upper electrode plate downwards within the extraction tank, it can compress the raw material and ensure a dense and dielectrically uniform material layer. When the upper and lower electrode plates are energized, ohmic heat is generated within the raw material, which is not limited by heat transfer area or temperature difference, resulting in a high heating rate and high thermal efficiency, and eliminating the need for an external heat exchanger and high-pressure conveying system. Based on ohmic heating, the water in the material layer is in a subcritical state under high temperature and high pressure, which can efficiently dissolve tea saponin. The high concentration of tea saponin causes the residual oil to be washed out and enter the liquid phase in an emulsion form. Furthermore, the extraction tank is divided into hot and cold zones based on non-full-size electrode plates, which, combined with the insulating porous plate below the material layer, form a circulation channel, achieving enhanced natural convection and mass transfer within the extraction tank and preventing the material from solidifying and coking on the electrode plate surface. In addition, the device uses a liquid collection tube to drive a porous upper electrode plate to press the material, which can achieve solid-liquid separation under subcritical temperature and pressure, so that high concentrations of tea saponins and oils are retained in the liquid phase, achieving efficient extraction of the target components.

[0024] Other features and advantages of the present invention will be described in detail in the following detailed description section. Attached Figure Description

[0025] The above and other objects, features and advantages of the present invention will become more apparent from the more detailed description of exemplary embodiments of the invention in conjunction with the accompanying drawings, wherein the same reference numerals generally represent the same components in the exemplary embodiments of the invention.

[0026] Figure 1 One of the schematic structural diagrams of an apparatus for extracting residual oil and tea saponins from camellia seed cake according to Embodiment 1 of the present invention is shown.

[0027] Figure 2 The second schematic structural diagram shows an apparatus for extracting residual oil and tea saponins from camellia seed cake according to Embodiment 1 of the present invention.

[0028] Figure 3 The third schematic structural diagram shows the apparatus for extracting residual oil and tea saponins from camellia seed cake according to Embodiment 1 of the present invention.

[0029] Figure 4 The fourth schematic structural diagram shows the apparatus for extracting residual oil and tea saponins from camellia seed cake according to Embodiment 1 of the present invention.

[0030] Figure 5 A schematic diagram of the water convection in the extraction tank according to Embodiment 1 of the present invention is shown.

[0031] Explanation of reference numerals in the attached figures:

[0032] 1. Extraction liquid discharge valve; 2. Liquid collection pipe; 3. Threaded sealing section; 4. Upper electrode plate; 41. Mesh; 5. Extraction tank; 6. Lower electrode plate; 61. Insulating porous mesh plate; 62. Circular conductive sheet; 7. Discharge valve; 8. Feed inlet; 9. Drive device. Detailed Implementation

[0033] Preferred embodiments of the invention will now be described in more detail. While preferred embodiments of the invention are described below, it should be understood that the invention can be implemented in various forms and should not be limited to the embodiments set forth herein. Rather, these embodiments are provided so that the invention will be thorough and complete, and will fully convey the scope of the invention to those skilled in the art.

[0034] Example 1:

[0035] like Figure 1-4 As shown, this embodiment provides an extraction device for residual oil and tea saponins from camellia seed cake, comprising:

[0036] Extraction tank 5, which is an insulated cylinder and has a feed inlet 8 at the top;

[0037] Liquid collection pipe 2, the lower end of which is movably inserted into the top of extraction tank 5, and the upper end of liquid collection pipe 2 extends to the outside of extraction tank 5 and is equipped with extraction liquid discharge valve 1.

[0038] The upper electrode plate 4 has an outer periphery that matches the inner periphery of the extraction tank 5. The upper electrode plate 4 is connected to one end of the liquid collection tube 2. The upper electrode plate 4 is provided with a mesh 41 to allow the liquid collection tube to communicate with the liquid collection tube 2. The liquid collection tube 2 can drive the upper electrode plate 4 to make piston movements in the extraction tank 5.

[0039] The lower electrode plate 6 is located above the bottom of the extraction tank 5.

[0040] In this embodiment, the extraction tank 5 is a vertical, pressure-resistant cylindrical tank with a smooth and insulated inner wall and a feed inlet 8 on the side wall; the upper electrode plate 4 is composed of a rigid outer ring and a central conductive mesh surface, which is placed horizontally inside the extraction tank 5 and can move up and down. Its mesh surface is also the filter surface for solid-liquid separation during pressing at the same temperature, so the mesh surface area can be maximized and the strength of the upper electrode plate 4 can be improved by reinforcing ribs; the lower electrode plate 6 is located at the bottom of the extraction tank 5 and is parallel to the upper electrode plate 4; the liquid collection tube 2 is vertically inserted into the extraction tank 5 and connected to the upper electrode plate 4. The liquid collection tube 2 can move up and down inside the extraction tank 5 and drive the upper electrode plate 4 to make piston movements.

[0041] The device is used as follows:

[0042] Feeding process: such as Figure 1As shown, the liquid collection pipe 2 is raised, which moves the upper electrode plate 4 upward until it is located above the feed inlet 8. The raw material enters the extraction tank 5 through the feed inlet 8. Then, the liquid collection pipe 2 is lowered until the electrode plate 4 is located at a suitable position below the feed inlet 8. At the same time, a certain amount of water is added through the feed inlet 8 to form a liquid seal.

[0043] Extraction process: such as Figure 2 As shown, the upper electrode plate 4 and the lower electrode plate 6 are connected to a power source. After ohmic heating, the water in the extraction tank 5 reaches a subcritical state, and the gas is discharged through the extract outlet valve 1 to stabilize the pressure inside the tank. After heating for a period of time, the target component enters the liquid phase from the solid phase, and the extraction ends.

[0044] Pressing process: such as Figure 3 As shown, when the liquid collection tube 2 is adjusted downward, the material in the extraction tank 5 is squeezed by the upper electrode plate 4. The liquid phase enters the liquid collection tube 2 through the mesh 41 of the upper electrode plate 4 and is discharged through the extract liquid discharge valve 1.

[0045] Specifically, water is highly polar at room temperature and pressure. In the subcritical state, the hydrogen bonds in water open or weaken as temperature increases. Therefore, by controlling the temperature and pressure of subcritical water and altering its polarity, it is possible to extract water-soluble to fat-soluble active ingredients from natural products. Thus, this embodiment uses subcritical water as the extractant to simultaneously extract residual oil and tea saponins from camellia seed cake. Compared to using ordinary water as the extractant, subcritical water provides higher solubility of tea saponins, making it easier to elute the residual oil from the cake and stabilize it in the subcritical aqueous phase in an emulsion form. Therefore, a lower liquid-to-solid ratio can be used, resulting in lower extractant recovery costs.

[0046] Traditional direct heating (such as using air or steam as the heating medium) or indirect heating (transferring heat through heated walls) is difficult to achieve precise temperature control and uniform heating; heat transferred by radiation is often preferentially absorbed by shallow materials, resulting in uneven heating. Ohmic heating utilizes the electrical conductivity of materials. When current passes through the material, electrical energy is converted into heat energy within the material, thus heating it directly and uniformly. This process is not limited by the heating area or temperature difference, the equipment structure is compact, and the thermal energy utilization rate is high. In this embodiment, after the upper electrode plate 4 and the lower electrode plate 6 are energized, ohmic heat is generated inside the raw material, and the high temperature and high pressure environment puts the water inside the raw material into a subcritical state.

[0047] Although subcritical water as an extractant can improve the solubility of residual oil and tea saponins, if the subcritical state cannot be maintained during the solid-liquid separation process after extraction, tea saponins will precipitate from the liquid phase due to decreased solubility. Simultaneously, oils that have entered the liquid phase due to the emulsifying effect of tea saponins will also precipitate out of the liquid phase and return to the solid phase, inevitably leading to a decrease in the extraction rate of the target components. This means that the advantages of subcritical water extraction are not fully realized. In this embodiment, the liquid collection tube 2 drives the porous upper electrode plate 4 to compress the material, ensuring a more thorough separation of the solid and liquid phases at the extraction temperature.

[0048] Optionally, the lower electrode plate 6 includes:

[0049] An insulating porous mesh plate 61, the outer periphery of which is connected to the inner periphery of the extraction tank 5;

[0050] A circular conductive sheet 62, the diameter of which is smaller than the inner diameter of the extraction tank 5, is centrally located on the lower surface of the insulating porous mesh plate 61.

[0051] Specifically, since there is no stirring device in the extraction tank 5, as the process proceeds, the camellia cake particles settle, causing moisture loss from the material near the lower electrode plate 6. If moisture is not replenished, it will dry out and even affect conductivity, making heating impossible. In this embodiment, firstly, the diameter of the circular conductive sheet 62 is set smaller than the inner diameter of the extraction tank 5, placing the material layer in the projection area directly above the circular conductive sheet 62 in the electric field to obtain more current distribution and higher temperature; while the subcritical water temperature in the annular space outside the projection area is lower, thus creating a temperature and density difference between the two areas, forming a driving force for natural convection. Secondly, an insulating porous mesh plate 61 is set above the circular conductive sheet 62, which not only avoids direct contact between the camellia cake material layer and the electrode plate, but also maintains a circulating water flow channel below the camellia cake material layer, forming a smooth natural convection path. Based on this setting, not only is the problem of material drying on the surface of the lower electrode plate 6 solved, but the heat and mass transfer efficiency in the extraction tank 5 is also higher, and the extraction of the target components is more complete. The natural convection of water in the extraction tank 5 is as follows. Figure 5 As shown.

[0052] Optionally, the bottom of the extraction tank 5 is provided with a discharge valve 7, which can be opened or closed, and the lower electrode plate 6 is disposed on the discharge valve 7.

[0053] Specifically, the lower electrode plate 6 is fixed to the inner side of the unloading valve and opens and closes in sync with the unloading valve 7. For example... Figure 4 As shown, after pressing is completed, the discharge valve 7 of the extraction tank 5 can be opened, and the extraction residue will be discharged from the discharge valve 7.

[0054] Optionally, the device for extracting residual oil and tea saponins from camellia seed cake also includes:

[0055] The driving device 9 is connected to the liquid collection tube 2 and is used to drive the liquid collection tube 2 to move up and down.

[0056] Optionally, the top of the extraction tank 5 is provided with a threaded sealing section 3, and the liquid collection tube 2 is threadedly connected to the threaded sealing section 3. The driving device 9 can drive the liquid collection tube 2 to rotate so that the liquid collection tube 2 moves up and down.

[0057] Specifically, the threaded sealing section 3 is placed at the top of the extraction tank, and its internal thread is nested with the external thread of the liquid collection tube 2; the upper part of the liquid collection tube 2 is connected to the drive device 9, which provides power for the liquid collection tube 2 to rotate in or out.

[0058] Optionally, the liquid collection tube 2 is connected to the upper electrode plate 4 via a connecting section 21, which gradually narrows from bottom to top.

[0059] Specifically, the connecting section 21 is a tapered tube, and the diameter of the lower end of the connecting section 21 is slightly smaller than the inner diameter of the extraction tank 5, but larger than the diameter of the circular mesh of the upper electrode plate 4.

[0060] Optionally, the aperture of mesh 41 is no greater than 0.38 mm.

[0061] Specifically, if the aperture of mesh 41 is too large, it will cause insufficient solid-liquid separation. Experiments have shown that the aperture of mesh 41 should not be greater than 0.38 mm.

[0062] Optionally, the liquid collection tube 2 is provided with a conductive slip ring, which is connected to the upper electrode plate 4.

[0063] In this embodiment, the liquid collection tube 2 is a conductor. One pole of the external AC power supply is introduced through a conductive slip ring fixed on the liquid collection tube 2, and then connected to the upper electrode plate 4 via the liquid collection tube 2. The other pole of the external AC power supply is introduced through the discharge valve 7 and connected to the lower electrode plate 6.

[0064] Optionally, the number of teeth in the threaded sealing section 3 is not less than 16.

[0065] Specifically, the threaded sealing section 3 serves two main functions: firstly, it utilizes the high-viscosity sealing oil in the threaded slits to achieve the necessary sealing conditions; secondly, it provides a precise rotational path for the liquid collection tube. Tests have shown that the number of teeth in the threaded sealing section 3 should not be less than 16.

[0066] Optionally, a sealing ring is provided at the edge of the upper electrode plate 4.

[0067] Specifically, a sealing ring is provided on the outer side of the rigid outer ring of the upper electrode plate 4, so that it remains in close contact with the inner wall of the extraction tank 5 during rotation.

[0068] Example 2:

[0069] This embodiment provides a method for using an extraction device for residual oil and tea saponins in camellia seed cake. Utilizing the extraction device from Embodiment 1, the method includes the following steps:

[0070] Feeding process: The liquid collecting tube 2 is rotated upward by the drive device 9, which moves the upper electrode plate 4 upward until it is located above the feed inlet 8. The raw material with a liquid-to-solid ratio of 1:1 enters the extraction tank 5 through the feed inlet 8. Then, the liquid collecting tube 2 is rotated downward by the drive device 9 to a suitable position below the feed inlet 8, and a certain amount of water is added through the feed inlet 8 to form a liquid seal.

[0071] Extraction process: After power is turned on and ohmic heating is applied, the subcritical water temperature inside the tank reaches 150℃. Gas is discharged through extract outlet valve 1 to stabilize the pressure inside the tank. Heating for 40 minutes completes the extraction.

[0072] Pressing stage: The liquid collection pipe 2 is adjusted downward by the drive device 9, and the material in the tank is squeezed by the upper electrode plate 4. The liquid phase enters the liquid collection pipe 2 through the hole of the upper electrode plate 4 and is discharged through the extract discharge valve 1.

[0073] Unloading process: Open the bottom valve of the extraction tank, and the extraction residue will be discharged from the unloading valve 7.

[0074] Tests showed that the tea saponin content in the extract could reach 0.1 g / mL, and the oil content could reach 0.04 g / mL.

[0075] Comparative Example 1:

[0076] The difference between this comparative example and Example 2 is that the water temperature in the tank during the extraction process was 75℃ (non-subcritical state). After extraction, the extract was tested, and the tea saponin content was 0.0014 g / mL, and the oil content was 0.0005 g / mL. It is evident that the excellent solubility of subcritical water requires less extractant to extract residual oil and tea saponin. The low liquid-to-solid ratio results in lower throughput, lower energy consumption, and greater economy in the subsequent extractant recovery process.

[0077] Comparative Example 2:

[0078] The difference between this comparative example and Example 2 is that the diameter of the circular conductive sheet 62 is equal to the inner diameter of the extraction tank 5, and there is no porous insulating mesh. After ohmic heating, the circuit pressure and current are initially normal, but after more than ten minutes, the current becomes very small, the system cannot maintain the high temperature, and the extraction fails. Upon disassembly, it was found that the material layer close to the lower electrode plate had dried out. Therefore, setting the diameter of the circular conductive sheet 62 to be smaller than the inner diameter of the extraction tank 5 and simultaneously installing a porous insulating mesh can solve the problem of material drying on the surface of the lower electrode plate 6.

[0079] The various embodiments of the present invention have been described above. These descriptions are exemplary and not exhaustive, nor are they limited to the disclosed embodiments. Many modifications and variations will be apparent to those skilled in the art without departing from the scope and spirit of the described embodiments.

Claims

1. A device for extracting residual oil and tea saponins from camellia seed cake, characterized in that, include: Extraction tank (5), wherein the extraction tank (5) is an insulated cylinder and has a feed inlet (8) at the top; Liquid collection tube (2), the lower end of which is movably inserted into the top of the extraction tank (5), and the upper end of which extends to the outside of the extraction tank (5) and is provided with an extract liquid discharge valve (1); The upper electrode plate (4) is fitted with the inner circumference of the extraction tank (5) on its outer periphery. The upper electrode plate (4) is connected to one end of the liquid collection tube (2). The upper electrode plate (4) is provided with a mesh (41) to allow the extraction tank (5) to communicate with the liquid collection tube (2). The rigid outer ring of the upper electrode plate (4) is provided with a sealing ring to keep it in close contact with the inner wall of the extraction tank (5). The lower electrode plate (6) is disposed at the bottom of the extraction tank (5); The lower electrode plate (6) includes: An insulating porous mesh plate (61) is provided, the outer periphery of which is connected to the inner periphery of the extraction tank (5). A circular conductive sheet (62) is provided, the diameter of which is smaller than the inner diameter of the extraction tank (5), and the circular conductive sheet (62) is centrally located on the lower surface of the insulating porous mesh plate (61).

2. The apparatus for extracting residual oil and tea saponins from camellia seed cake according to claim 1, characterized in that, The bottom of the extraction tank (5) is provided with a discharge valve (7), which can be opened or closed, and the lower electrode plate (6) is disposed on the discharge valve (7).

3. The apparatus for extracting residual oil and tea saponins from camellia seed cake according to claim 1, characterized in that, Also includes: A driving device (9) is connected to the liquid collection tube (2) and is used to drive the liquid collection tube (2) to move up and down.

4. The apparatus for extracting residual oil and tea saponins from camellia seed cake according to claim 3, characterized in that, The extraction tank (5) is provided with a threaded sealing section (3) at the top. The liquid collection tube (2) is threadedly connected to the threaded sealing section (3). The driving device (9) can drive the liquid collection tube (2) to rotate so that the liquid collection tube (2) moves up and down.

5. The apparatus for extracting residual oil and tea saponins from camellia seed cake according to claim 1, characterized in that, The liquid collection tube (2) is connected to the upper electrode plate (4) through a connecting section (21), which gradually narrows from bottom to top.

6. The apparatus for extracting residual oil and tea saponins from camellia seed cake according to claim 1, characterized in that, The aperture of the mesh (41) is no greater than 0.38 mm.

7. The apparatus for extracting residual oil and tea saponins from camellia seed cake according to claim 1, characterized in that, The liquid collection tube (2) is provided with a conductive slip ring, which is connected to the upper electrode plate (4).

8. The apparatus for extracting residual oil and tea saponins from camellia seed cake according to claim 4, characterized in that, The number of teeth in the threaded sealing section (3) is not less than 16.

9. The apparatus for extracting residual oil and tea saponins from camellia seed cake according to claim 1, characterized in that, The upper electrode plate is provided with a sealing ring at its edge.

Images