Low-energy-consumption microalgae cell separating and harvesting device and method based on plant fibers

Abstract

The invention discloses a low-energy-consumption microalgae cell separating and harvesting device and method based on plant fibers, and particularly relates to the field of microalgae cell concentration and separation. Comprising a separation box, the separation box communicates with a liquid inlet pipe and an air inlet pipe, the liquid inlet pipe is provided with a first valve, the air inlet pipe is connected with an inflation pump, the separation box communicates with a liquid discharging pipe, the liquid discharging pipe is provided with a second valve, the two sides of the separation box communicate with feeding channels, and the space between the two feeding channels is filled with a plant fiber filtering layer. A fixed plate and a movable plate are arranged in the separation box, a first water passing hole is formed in the fixed plate, a driving assembly used for driving the movable plate to slide in the separation box is arranged on the movable plate, and a second water passing hole is formed in the movable plate. By the adoption of the technical scheme, the problem that an existing device cannot achieve efficient collection and separation of a large number of algae cells in an artificial culture scene or an algae bloom scene of unicellular algae is solved, and resource utilization of natural plant fiber materials and efficient harvesting of the algae cells are achieved.

Description

Technical Field

[0001] The invention relates to the field of algae cell concentration and separation, and in particular to a low-energy consumption microalgae cell separation and harvesting device and method based on plant fiber. Background Art

[0002] In the field of health products, algae are often used to enhance immunity, promote digestion, improve skin quality, etc. In the field of medicine, some algae extracts are used to develop anti-cancer drugs, antioxidants and antibacterial agents.

[0003] Under artificial culture conditions, single-cell organisms such as Spirulina and Haematococcus pluvialis can be cultured at high density by precisely controlling conditions such as light, temperature, pH value, and nutrient concentration. As the algae biomass increases, harvesting becomes a key step. The choice of harvesting method depends on the culture scale, cost-effectiveness, and the needs of subsequent processing. Common harvesting methods include centrifugation, filtration, natural sedimentation, and flocculation. Centrifugation and filtration are highly efficient, but consume a lot of energy; natural sedimentation and flocculation are relatively energy-efficient, but may require longer processing time. The harvested algae mixture contains a large amount of water and impurities, and solid-liquid separation is required to remove excess water and impurities in order to prepare various health products, pharmaceutical raw materials, or food additives. In the natural environment, eutrophication of lakes and reservoirs can lead to the massive reproduction of algae. Physical salvage is one of the important means of dealing with algae blooms. The algae on the water surface are gathered and salvaged through mechanical equipment such as boats and nets. During the salvage process, issues such as salvage efficiency, impact on aquatic organisms, and post-salvage treatment need to be considered. The salvaged algae mixture contains a large amount of water and impurities, and solid-liquid separation is also required to reduce the processing volume.

[0004] In response to the above problems, a Chinese patent (patent announcement number: CN218280924U) discloses a cyclone-type separation device for spirulina. This technical solution uses airflow centrifugation to separate spirulina, but it may lead to reduced separation efficiency and high energy consumption and cost. A Chinese patent (patent announcement number: CN103881917A) discloses a large-scale harvesting process for Haematococcus pluvialis. This process uses carboxymethyl cellulose and chitosan polymers as flocculants, has a large harvest volume, and can be applied to industrial-scale production, but the cost of the flocculant is relatively high. A Chinese patent (patent publication number: CN115581956A) discloses an algae bloom capture and concentration device, which uses a diversion port, a pressure difference diversion system, and an algae slurry collection tank to capture, concentrate, collect and store algae blooms, solving the problem of low efficiency in existing bloom control technologies. However, the water content of the concentrated algae liquid is still high, and the storage time of the algae liquid is short.

[0005] Based on this, there is an urgent need for an algae cell harvesting and separation device that is efficient and low-cost. Summary of the invention

[0006] The present invention aims to provide a low-energy microalgae cell separation and harvesting device and method based on plant fibers, which solves the problem that existing devices are unable to achieve large-scale and efficient collection and separation of algae biomass in artificial algae cultivation scenarios or algal bloom scenarios.

[0007] In order to achieve the above-mentioned purpose, the technical scheme of the present invention is as follows: a low-energy consumption microalgae cell separation and harvesting device based on plant fiber, comprising a separation box, the top of the separation box is respectively connected with a liquid inlet pipe and an air inlet pipe, the liquid inlet pipe is provided with a first valve, the air inlet pipe is connected with an air pump, the bottom of the separation box is connected with a discharge pipe, the discharge pipe is provided with a second valve, both sides of the separation box are connected with a feed channel, a plant fiber filter layer is filled between the two feed channels, a fixed plate and a movable plate located directly above the fixed plate are provided in the separation box, the fixed plate is flush with the bottom wall in the feed channel, a first water hole is provided on the fixed plate, a driving assembly is provided on the movable plate, the driving assembly is used to drive the movable plate to slide in the separation box, and a second water hole is provided on the movable plate.

[0008] Furthermore, the driving assembly includes a fixed block, which is fixedly connected to the upper surface of the movable plate. A threaded hole is provided at the center of the fixed block. A threaded rod with one end passing through the top of the separation box is threadedly connected to the threaded hole. An optical axis is integrally formed on the upper side of the threaded rod. A through hole is provided on the top of the separation box, which is rotationally sealed with the optical axis. The optical axis is connected to a driving motor via a gear set, and the driving motor is arranged on the top of the separation box.

[0009] Furthermore, the upper surface of the fixing plate is designed to be inclined, and the first water hole is located on the lower side of the fixing plate.

[0010] Furthermore, a liquid outlet pipe is connected to the first water hole, a flow meter is arranged in the liquid outlet pipe, and the flow meter is electrically connected to the driving motor and the air pump through a controller.

[0011] Furthermore, the included angle between the center lines at both ends of each feed channel is between 135° and 150°.

[0012] Furthermore, the lowest point of the free end of each of the feed channels is not lower than 1 / 2 of the distance between the top of the connection between the feed channel and the separation box and the inner top wall of the separation box.

[0013] Furthermore, the plant fiber filter layer includes two filter nets, and one or more of straw, bamboo powder and wood powder is laid between the two filter nets.

[0014] Furthermore, in the height range of 5-15% at the bottom and top of the plant fiber filter layer, the average length of the plant fiber filter layer is greater than 1.5 cm, and in the height range of 85-95% in the middle of the plant fiber filter layer, the average length of the plant fiber filter layer is greater than 1 mm.

[0015] Furthermore, a push block is provided at the bottom of the fixed plate, the cross-sectional shape of the push block is triangular, and the height of the push block gradually decreases from the center of the fixed plate to both sides.

[0016] Furthermore, the method for using the separation and harvesting device is as follows: S1. Place the plant fiber filter layer between the two feed channels, and keep the plant fiber filter layer filling the feed channels and the end thereof being located outside the feed channels; S2, driving the movable plate to squeeze the plant fiber filter layer through the driving assembly, so as to change the pore size between the plant fiber filter layers, and clamping the rubber pad in the gap between the plant fiber filter layer and the end of the feed channel, and sealing the free end of the feed channel with the help of the rubber pad and the plant fiber filter layer; S3, opening the first valve and injecting algae liquid into the separation box, closing the first valve after the injection is completed, and pressurizing the inside of the separation box through an air pump to improve the efficiency of the liquid passing through the plant fiber filter layer; S4. After filtering for a period of time, the driving assembly is used to drive the moving plate to move upward and remove the rubber pad, so that the plant fiber filter layer is gradually reset to change the pore size inside the plant fiber filter layer, and the algae liquid collected by the plant fiber filter layer moves downward or shifts, thereby facilitating the improvement of the filtering effect of the plant fiber filter layer, thereby achieving continuous filtering and harvesting; S5, after the free end of the feed channel is sealed again with the help of the rubber pad and the plant fiber filter layer, the air pump is used to continue pressurizing the filtration and harvesting, and steps S4 and S5 are continuously repeated until the space size of the plant fiber filter layer does not change; S6, taking out the rubber pad and pushing the plant fiber filter layer from one feeding channel to another feeding channel for a distance, so that the plant fiber filter layer that has not been filtered and harvested enters the separation box to continue filtering and harvesting, and the driving assembly drives the moving plate to squeeze the plant fiber filter layer inside the separation box again; S7. Repeat steps S1-S6 until the plant fiber filter layer is exhausted to complete the concentrated collection of the algae liquid, and finally discharge the mixed solids of the concentrated algae mud and the natural plant fiber from the device.

[0017] Compared with the prior art, this solution has the following beneficial effects: 1. This solution uses plant fiber as the filter layer, which is low-cost and can achieve filtration and algae mud recycling at one time. It is convenient, fast, energy-saving and environmentally friendly. The algae liquid and the plant fiber filter layer are compressed by an air pump to form a mixture, which reduces energy consumption and cost, improves efficiency, and reduces the moisture content of the mixture, making subsequent drying and dehydration faster. It solves the problem of solid-liquid separation of bulk single-cell organisms such as Spirulina and Haematococcus pluvialis, as well as the impact of algae blooms on the environment, and recycles them for use as fertilizer for crops.

[0018] 2. Existing processes may be limited by the performance and structural design of the filter material, resulting in limited filtering effects. This solution innovatively uses natural plant fibers such as straw, bamboo powder, and wood powder as filter media, and uses their unique physical and chemical properties to significantly improve filtering performance. The porous structure and high specific surface area of ​​these plant fibers enable them to more effectively capture and retain tiny particles, suspended matter, and some soluble substances in the algae solution, thereby improving filtering accuracy and efficiency.

[0019] 3. While pursuing high-efficiency filtration, existing processes often ignore the requirements of environmental protection and sustainability. The plant fiber materials such as straw, bamboo powder, and wood powder used in this solution are all derived from renewable resources and will not produce harmful substances during use, achieving a perfect combination of environmental protection and sustainability. This choice not only reduces the negative impact on the environment, but also promotes the recycling of resources.

[0020] 4. Existing processes may result in high production costs due to the use of high-cost materials or complex process flows. However, the plant fiber materials used in this solution are widely available, inexpensive, and the process flow is relatively simple, which significantly reduces production costs. At the same time, due to the improvement of filtration performance and efficiency, the process of this application can also shorten the processing time while ensuring the processing quality, further improving the economic benefits.

[0021] 5. Existing processes may not be able to effectively remove certain specific impurities or pollutants when treating algae liquid. However, this solution, through in-depth research on the filtration mechanism of plant fiber materials and the characteristics of algae liquid, found that the mixed use of straw, bamboo powder, wood powder and other materials can remove these difficult-to-treat impurities. This not only improves the quality of algae liquid treatment, but also provides more convenient conditions for subsequent processing steps.

[0022] 6. Compared with the existing processes, the filtration process using straw, bamboo powder and wood powder as specific plant fibers has shown unexpected technical effects in terms of filtration performance, environmental protection and sustainability, cost-effectiveness, impurity removal ability, application potential and market acceptance. These advantages make the process more competitive and have broader development prospects in the field of algae liquid treatment. BRIEF DESCRIPTION OF THE DRAWINGS

[0023] Figure 1 is an axonometric view of a low-energy consumption microalgae cell separation and harvesting device based on plant fiber in Example 1; Figure 2 This is a front view of a low-energy consumption microalgae cell separation and harvesting device based on plant fiber in Example 1; Figure 3 is a top view of a low-energy consumption microalgae cell separation and harvesting device based on plant fiber in Example 1; Figure 4 yes Figure 3 Sectional view of AA in the middle; Figure 5 yes Figure 3 Cross-sectional view of the middle BB; Figure 6 This is a front view of a low-energy consumption microalgae cell separation and harvesting device based on plant fiber in Example 1; Figure 7 yes Figure 6 Cross-sectional view of CC; Figure 8 It is a cross-sectional view of a low-energy consumption microalgae cell separation and harvesting device based on plant fiber in Example 2. DETAILED DESCRIPTION

[0024] The present invention is further described in detail below through specific embodiments: The figure marks in the drawings of the specification include: separation box 1, liquid inlet pipe 2, air inlet pipe 3, first valve 4, hose 5, air pump 6, support column 7, discharge pipe 8, second valve 9, feed channel 10, fixed plate 11, movable plate 12, first water hole 13, push block 14, second water hole 15, fixed block 16, threaded rod 17, optical axis 18, drive motor 19, bracket 20, gear 21, liquid outlet pipe 22, flow meter 23.

[0025] Example: Figures 1 to 7As shown, a low-energy consumption microalgae cell separation and harvesting device based on plant fiber comprises a square separation box 1, the top of the separation box 1 is respectively connected with a liquid inlet pipe 2 and an air inlet pipe 3, a first valve 4 is installed on the liquid inlet pipe 2, and an air inlet pipe 3 is connected to an air pump 6 through a hose 5. Support columns 7 are welded at the four corners of the bottom of the separation box 1, and a drain pipe 8 is connected to the bottom center of the separation box 1, and a second valve 9 is installed on the drain pipe 8. The left and right sides of the separation box 1 are connected with a feed channel 10. In this embodiment, the included angle of the center lines of the two ends of each feed channel 10 is between 135° and 150°, and the lowest point of the free end of each feed channel 10 is not lower than 1 / 2 of the distance between the top of the connection between the feed channel 10 and the separation box 1 and the inner top wall of the separation box 1, so that during the separation and filtration process, when the air pump 6 is used to pressurize, the liquid or the separated water will not overflow from the feed channel 10, ensuring the stability and reliability of the pressurized filtration. The left and right sides of the separation box 1 are both provided with openings connected to the feed channel 10, and a plant fiber filter layer is filled between the two feed channels 10, and the plant fiber filter layer is in a relatively fluffy state at this time; the plant fiber filter layer includes two filter screens, and one or more plant fibers selected from straw, bamboo powder, and wood powder are laid between the two filter screens. In the plant fiber filter layer, within the 5-15% height range between the bottom and the top, the average length of the plant fiber filter layer is greater than 1.5 cm, and in the plant fiber filter layer, within the 85-95% height range in the middle, the average length of the plant fiber filter layer is greater than 1 mm.

[0026] A fixed plate 11 and a movable plate 12 located directly above the fixed plate 11 are provided in the separation box 1. The fixed plate 11 and the movable plate 12 are respectively connected to the corresponding inner walls of the separation box 1. The upper surface of the fixed plate 11 is flush with the bottom wall in the feed channel 10 (that is, the upper surface of the fixed plate 11 is flush with the bottom of the openings on the left and right sides of the separation box 1). A first water hole 13 is opened on the fixed plate 11. The upper surface of the fixed plate 11 adopts an inclined design. The first water hole 13 is located on the lower side of the fixed plate 11, which is convenient for water separation and discharge. A push block 14 is provided at the bottom center of the fixed plate 11. The cross-sectional shape of the push block 14 is triangular, and the height of the push block 14 gradually decreases from the center of the fixed plate 11 to both sides, so that the plant fibers in the middle of the plant fiber filter layer can be pushed to both sides during the downward pressing process with the help of the push block 14, so that part of the algae bloom is directly harvested to the middle of the plant fiber filter layer during separation and filtration, and at the same time, it is beneficial to maintain the separation and filtration efficiency of the upper part of the plant fiber filter layer during the resetting process.

[0027] A driving assembly is provided on the moving plate 12, and the driving assembly is used to drive the moving plate 12 to slide in the separation box 1. A plurality of second water holes 15 are arranged in an array on the moving plate 12, and the plurality of second water holes 15 do not interfere with the push block 14. The driving assembly includes a fixed block 16, which is welded to the center of the upper surface of the moving plate 12, and a threaded hole is provided at the center of the fixed block 16, and a threaded rod 17 whose upper end passes through the top of the separation box 1 is threadedly connected in the threaded hole, and an optical axis 18 is integrally formed on the upper side of the threaded rod 17, and a through hole is provided on the top of the separation box 1 to be rotatably sealed with the optical axis 18, and the optical axis 18 is connected to a driving motor 19 through a gear set, and the driving motor 19 is arranged on the top of the separation box 1 through a bracket 20. The gear set of this embodiment is a pair of gears 21 meshing with each other, and the two gears 21 are respectively arranged on the optical axis 18 and the output shaft of the driving motor 19.

[0028] The method of using the separation and harvesting device is as follows: S1. Place the plant fiber filter layer between two feed channels 10, keep the plant fiber filter layer filling the feed channel 10 and the end thereof outside the feed channel 10, and use the fixing plate 11 to facilitate pushing the plant fiber filter layer from one feed channel 10 into another feed channel 10.

[0029] S2, the optical axis 18 and the threaded rod 17 are driven to rotate by the driving motor 19 and the gear set. After the threaded rod 17 rotates, it drives the moving plate 12 to rise or fall with the help of the fixed block 16, so as to change the pore size between the plant fiber filter layers; in the initial state, the internal pores of the plant fiber filter layer are the smallest. Then, a rubber pad is clamped in the gap between the plant fiber filter layer and the end of the feed channel 10, and the free end of the feed channel 10 is sealed with the help of the rubber pad and the plant fiber filter layer to ensure the reliability of the gas pressurized separation filtration.

[0030] S3, opening the first valve 4 and injecting algae liquid into the separation box 1, and closing the first valve 4 after the injection is completed. The inside of the separation box 1 is pressurized by the air pump 6 to improve the efficiency of the liquid passing through the plant fiber filter layer.

[0031] S4. After filtering for a period of time, the separation and filtration efficiency decreases or separation and filtration cannot continue because the surface of the plant fiber filter layer absorbs part of the algae liquid. At this time, the fixed block 16 and the movable plate 12 are driven by the driving motor 19, the gear set and the optical axis 18 to move upward for a distance, and then the rubber pad is taken out. At this time, the filter mesh and the plant fiber in the plant fiber filter layer are relatively displaced due to the squeezing, so that the pores between the plant fibers become larger, and the algae liquid collected by filtration will fall into the inside of the plant fiber, thereby maintaining the separation and filtration efficiency of the plant fiber filter layer and realizing the continuity of filtration and harvesting.

[0032] S5. After the driving motor 19 stops, the free end of the feed channel 10 is sealed again with the help of the rubber pad and the plant fiber filter layer, and then the air pump 6 is used to continue pressurizing the filtration and harvesting. Steps S4 and S5 are repeated until the spatial size of the plant fiber filter layer does not change. At this time, the plant fiber filter layer is close to the size of the initial state.

[0033] S6. Take out the rubber pad and push the plant fiber filter layer from one feed channel 10 to another feed channel 10 for a distance, so that the plant fiber filter layer that has not been filtered and harvested enters the separation box 1 to continue filtering and harvesting, and the driving assembly drives the moving plate 12 again to squeeze the plant fiber filter layer inside the separation box 1.

[0034] S7. Repeat steps S1-S6 until the plant fiber filter layer is exhausted to complete the concentration and harvesting of the algae liquid, thereby realizing the recycling of natural plant fibers as a carbon source component together with algae mud, or using them for fermenting silage and feeding ruminants, thereby realizing resource utilization.

[0035] The separation and harvesting device of this embodiment can be used to separate artificially cultured algae liquid, for example: Spirulina, as an important microalgae, when cultivated on a large scale in a runway pool, its harvesting process often consumes a lot of energy and is inefficient. In order to overcome this problem, this embodiment proposes a low-energy spirulina harvesting device based on plant fiber, which aims to achieve efficient, continuous and low-energy harvesting of spirulina through optimized structural design, and the harvested spirulina is mixed with plant fiber for silage fermentation, which can fully utilize the nutritional advantages of both. The high protein, high vitamin and other nutrients in Spirulina can make up for the problem of insufficient nutrition in plant fiber, improve the overall nutritional value of feed, and be used to feed ruminants.

[0036] The separation and harvesting device of this embodiment can also be used to separate algae blooms. With the increasing severity of the eutrophication problem of water bodies, the frequent occurrence of algae blooms has become a major challenge affecting water quality safety and ecological balance. Effectively harvesting and utilizing these over-proliferated algae can not only alleviate environmental pressure, but also be used as biomass resources to promote sustainable development. This embodiment is based on an innovative technology that uses mechanical force to adjust the pore size of natural plant fibers to achieve efficient concentration and separation of algae, providing a new way for algae bloom control and resource utilization.

[0037] Embodiment 2: like Figure 8 As shown, the difference between this embodiment and embodiment 1 is that: in this embodiment, a liquid outlet pipe 22 is fixedly connected to the first water hole 13, and a flow meter 23 is provided in the liquid outlet pipe 22. The flow meter 23 is electrically connected to the drive motor 19 and the air pump 6 through the controller. By monitoring the water flow, the automation of algae liquid filtration and separation can be achieved, thereby improving the efficiency of harvesting.

[0038] The difference between the method of use of this embodiment and that of embodiment 1 is only in step S4. Step S4 of the method of use of this embodiment is as follows: the flow rate of water separated and filtered is automatically monitored by the flow meter 23. If the flow rate is lower than the preset value, the flow meter 23 will feed back the signal to the controller, and the controller will start the drive motor 19 and the air pump 6. After the drive motor 19 is started, the optical axis 18 and the threaded rod 17 are driven to rotate through the gear set. After the threaded rod 17 rotates, the moving plate 12 is driven to move upward for a distance through the fixed block 16. Then the rubber pad is taken out. At this time, the filter screen and the plant fiber in the plant fiber filter layer are relatively displaced due to the extrusion, so that the pores between the plant fibers become larger, and the algae liquid collected by filtration will be partially split or fall into the inside of the plant fiber, thereby maintaining the separation and filtration efficiency of the plant fiber filter layer and realizing the continuity of filtration and collection. This embodiment can realize the automatic operation of filtering and collecting algae liquid by a single-stage plant fiber filter layer through the flow meter 23 and the controller, thereby improving the efficiency of the operation.

[0039] The above are only embodiments of the present invention, and the common knowledge such as the known specific structures and / or characteristics in the scheme are not described in detail here. It should be pointed out that for those skilled in the art, several deformations and improvements can be made without departing from the structure of the present invention, which should also be regarded as the protection scope of the present invention, and these will not affect the effect of the implementation of the present invention and the practicality of the patent. The scope of protection required by this application shall be based on the content of its claims, and the specific implementation methods and other records in the specification can be used to interpret the content of the claims.

Claims

1. A low-energy consumption microalgae cell separation and harvesting device based on plant fiber, characterized by: It includes a separation box, the top of which is respectively connected to a liquid inlet pipe and an air inlet pipe, the liquid inlet pipe is provided with a first valve, the air inlet pipe is connected to an air pump, the bottom of the separation box is connected to a liquid discharge pipe, the liquid discharge pipe is provided with a second valve, the air inlet pipe is connected to an air pump, both sides of the separation box are connected to feed channels, a plant fiber filter layer is filled between the two feed channels, a fixed plate and a movable plate located directly above the fixed plate are provided in the separation box, the fixed plate is flush with the bottom wall of the feed channel, a first water hole is provided on the fixed plate, a driving assembly is provided on the movable plate, the driving assembly is used to drive the movable plate to slide in the separation box, and a second water hole is provided on the movable plate.

2. The low-energy consumption microalgae cell separation and harvesting device based on plant fiber according to claim 1, characterized in that: The driving assembly includes a fixed block, which is fixedly connected to the upper surface of the movable plate. A threaded hole is provided in the center of the fixed block. A threaded rod with one end passing through the top of the separation box is threadedly connected to the threaded hole. An optical axis is integrally formed on the upper side of the threaded rod. A through hole is provided on the top of the separation box, which is rotationally sealed with the optical axis. The optical axis is connected to a driving motor via a gear set, and the driving motor is arranged on the top of the separation box.

3. The low-energy consumption microalgae cell separation and harvesting device based on plant fiber according to claim 2, characterized in that: The upper surface of the fixing plate is designed to be inclined, and the first water hole is located on the lower side of the fixing plate.

4. The low-energy consumption microalgae cell separation and harvesting device based on plant fiber according to claim 2, characterized in that: The first water hole is connected with a liquid outlet pipe, the liquid outlet pipe is provided with a flow meter, and the flow meter is electrically connected with the driving motor and the air pump through a controller.

5. The low-energy consumption microalgae cell separation and harvesting device based on plant fiber according to claim 1, characterized in that: The included angle between the center lines at both ends of each feed channel is between 135° and 150°.

6. The low-energy consumption microalgae cell separation and harvesting device based on plant fiber according to claim 5, characterized in that: The lowest point of the free end of each feed channel is not lower than 1 / 2 of the distance between the top of the connection between the feed channel and the separation box and the inner top wall of the separation box.

7. The low-energy consumption microalgae cell separation and harvesting device based on plant fiber according to claim 1, characterized in that: The plant fiber filter layer comprises two filter nets, and one or more of straw, bamboo powder and wood powder is laid between the two filter nets.

8. The low-energy consumption microalgae cell separation and harvesting device based on plant fiber according to claim 1, characterized in that: The plant fiber filter layer is located within the 5-15% height range at the bottom and the top, and the average length of the plant fiber filter layer is selected to be greater than 1.5 cm. The plant fiber filter layer is located within the 85-95% height range in the middle, and the average length of the plant fiber filter layer is selected to be greater than 1 mm.

9. The low-energy consumption microalgae cell separation and harvesting device based on plant fiber according to claim 1, characterized in that: A push block is provided at the bottom of the fixing plate. The cross-section of the push block is triangular, and the height of the push block gradually decreases from the center of the fixing plate to both sides.

10. A low-energy consumption microalgae cell separation and harvesting device based on plant fiber according to any one of claims 1 to 9, characterized in that: The method of using the separation and harvesting device is as follows: S1. Place the plant fiber filter layer between the two feed channels, and keep the plant fiber filter layer filling the feed channels and the end thereof being located outside the feed channels; S2, driving the movable plate to squeeze the plant fiber filter layer through the driving assembly, so as to change the pore size between the plant fiber filter layers, and clamping the rubber pad in the gap between the plant fiber filter layer and the end of the feed channel, and sealing the free end of the feed channel with the help of the rubber pad and the plant fiber filter layer; S3, opening the first valve and injecting algae liquid into the separation box, closing the first valve after the injection is completed, and pressurizing the inside of the separation box through an air pump to improve the efficiency of the liquid passing through the plant fiber filter layer; S4. After filtering for a period of time, the driving assembly is used to drive the moving plate to move upward and remove the rubber pad, so that the plant fiber filter layer is gradually reset to change the pore size inside the plant fiber filter layer, and the algae liquid collected by the plant fiber filter layer moves downward or shifts, thereby facilitating the improvement of the filtering effect of the plant fiber filter layer, thereby achieving continuous filtering and harvesting; S5, after the free end of the feed channel is sealed again with the help of the rubber pad and the plant fiber filter layer, the air pump is used to continue pressurizing the filtration and harvesting, and steps S4 and S5 are continuously repeated until the space size of the plant fiber filter layer does not change; S6, taking out the rubber pad and pushing the plant fiber filter layer from one feeding channel to another feeding channel for a distance, so that the plant fiber filter layer that has not been filtered and harvested enters the separation box to continue filtering and harvesting, and the driving assembly drives the moving plate to squeeze the plant fiber filter layer inside the separation box again; S7. Repeat steps S1-S6 until the plant fiber filter layer is exhausted to complete the concentrated harvesting of the algae liquid.

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