Solid-liquid separation device and separation method

Abstract

The invention discloses a solid-liquid separation device and a solid-liquid separation method, and belongs to the technical field of solid-liquid separation. The solid-liquid separation device comprises a solid-phase sedimentation unit, a clear liquid discharge unit, a middle membrane, a negative pressure automatic control system and a clear liquid storage tank, the solid-phase sedimentation unit comprises a feeding pipe, a first cone, a first barrel, a sedimentation pipe and a first discharge pipe; the clear liquid discharge unit comprises a clear liquid tank, a clear liquid suction pipe, a second cone, a second barrel and a second discharge pipe; the middle diaphragm is arranged between the first barrel and the second barrel; the negative pressure automatic control system is communicated with the first discharge pipe and the second discharge pipe; and the clear liquid storage tank is arranged on one side, far away from the second barrel, of the negative pressure automatic control system. By arranging the solid-phase settling unit, the clear liquid discharging unit, the middle membrane, the negative pressure automatic control system and the clear liquid storage tank, high-precision solid-liquid separation is achieved, and meanwhile the problems of blockage and solid particle damage are not prone to occurring.

Description

Technical Field

[0001] The present application relates to a solid-liquid separation device and a separation method, belonging to the technical field of solid-liquid separation. Background Art

[0002] The continuous separation of micron-sized solid particles from liquids is a key step in many production processes, such as microbial fermentation, solid catalytic reactions, or reaction crystallization processes. Among them, in solid catalytic reactions (such as Fischer-Tropsch synthesis), micron-sized solid catalysts and liquid products need to be continuously separated to enable the solid catalyst to continuously catalyze in the reactor while the liquid product is discharged outside the reactor. For example, the invention patent with the application number 202010855068.3 proposes a method and device for extracting clean liquid from a slurry bed, including the following steps: S1 The slurry in the slurry bed is siphoned into the sampling pipe and then sprayed into the settling tank, where the solid particles settle and return to the slurry bed through the discharge pipe; S2 The supernatant in the settling tank flows upward along the settling pipe, turns downward at the pipe intersection and flows into the clear liquid pipe and then into the clear liquid transition tank; S3 The clear liquid transition tank discharges liquid by overflow to maintain a constant liquid level and the pressure required for siphoning; S4 The gas in the sampling pipe enters the escape pipe and is continuously discharged to ensure that the liquid level in the escape pipe is always higher than the pipe intersection, thereby ensuring that the slurry bed and the clear liquid transition tank are always connected and the liquid levels are even. This technology can separate the solid catalyst and return it to the reactor. However, on the one hand, its separation accuracy is relatively low, the treatment volume of the clear liquid is small, and fine particles are not easy to settle and will be discharged with the clear liquid, which cannot meet the demand for large treatment volumes in industrial applications; on the other hand, when the solid concentration in the reactor is high, it is easy to cause blockage, and the overflow volume of the clear liquid cannot be adjusted in real time, resulting in abnormal situations.

[0003] In addition, in perfusion bioreactors, fresh liquid medium needs to be continuously infused into the bioreactor and part of the old medium needs to be removed, while micron-sized fermentation strains are left in the reactor for continuous fermentation. This process can significantly increase the yield of bioconversion and reduce the concentration of harmful metabolic wastes. Existing technologies usually adopt membrane separation methods, pumping the fermentation broth into a membrane filtration device outside the reactor by a centrifugal pump, filtering out the old liquid medium and transporting the solid fermentation strains back to the bioreactor. However, pumping the fermentation strains by a pump will cause certain damage to them, making the strains lose their activity, and even cause fatal damage to shear-sensitive microorganisms.

[0004] In addition, during the preparation of the cathode precursor of lithium batteries by reactive crystallization, most of the existing technologies use membrane tube separation to leave micron-sized precursors in the kettle and discharge the clear liquid outside the kettle to increase the solid content rate of the reactor. This method can not only precisely control the particle size and its distribution of the product, but also greatly improve the sphericity of the product and enhance the electrochemical performance of the cathode material. For example, the invention patent with the application number 202310030199.1 proposes a method for preparing a precursor of a cathode material for lithium-ion batteries and a draft tube type synthesis kettle, in which a membrane tube separation device is arranged in the stirring kettle, and when the liquid level reaches the overflow level, the membrane tube pump is started to pump and concentrate the mother liquor. However, in this technology, the membrane tube is completely immersed in the high-concentration solid slurry and is easily blocked and fails.

[0005] Based on the above situation, there is an urgent need to develop a solid-liquid separation device and a separation method to solve the problems existing in the prior art, such as low separation accuracy, easy blockage, and easy damage to solid particles. Summary of the Invention

[0006] To solve the above problems, a solid-liquid separation device and a separation method are provided. The solid-liquid separation device realizes high-precision solid-liquid separation through the setting of a solid-phase sedimentation unit, a clear liquid discharge unit, an intermediate membrane, a negative pressure automatic control system, and a clear liquid storage tank, and is not prone to blockage and damage to solid particles.

[0007] According to one aspect of the present application, the present application provides a solid-liquid separation device, including a solid-phase sedimentation unit, a clear liquid discharge unit, an intermediate membrane, a negative pressure automatic control system, and a clear liquid storage tank;

[0008] The solid-phase sedimentation unit includes a feed pipe, a first cone, a first cylinder, a sedimentation pipe, and a first discharge pipe; the clear liquid discharge unit includes a clear liquid tank, a clear liquid suction pipe, a second cone, a second cylinder, and a second discharge pipe; the intermediate membrane is arranged between the first cylinder and the second cylinder; the negative pressure automatic control system is communicated with the first discharge pipe and the second discharge pipe; the clear liquid storage tank is arranged on one side of the negative pressure automatic control system away from the second cylinder.

[0009] Specifically, the first cylinder in the solid-phase sedimentation unit provides a sufficient place for the gravitational sedimentation of solid particles. The solid particles settle and accumulate below the first cylinder and in the first cone, and then return to the reactor; the clear liquid enters the clear liquid discharge unit through the intermediate membrane and is discharged from the solid-liquid separation device, realizing solid-liquid separation.

[0010] Specifically, the first cylinder provides a sufficient place for the gravitational sedimentation of solid particles. The solid particles settle and accumulate below the first cylinder and in the first cone. The solid content above the first cylinder is greatly reduced, so that most of the area above and in the middle of the intermediate membrane is in a relatively clean liquid environment. On the one hand, it is beneficial to reduce the negative pressure filtration load of the intermediate membrane, and on the other hand, it reduces the probability of the intermediate membrane being blocked.

[0011] Specifically, the pore size of the intermediate membrane is smaller than the d 10 value.

[0012] Specifically, the present application does not make any specific limitation on the material of the intermediate diaphragm, and those skilled in the art may select a suitable material according to actual conditions.

[0013] Specifically, the intermediate membrane may be a filter membrane or a filter screen, wherein the filter membrane includes a ceramic membrane, a plastic membrane or a sand filter membrane, and the filter screen includes a plastic filter screen or a metal filter screen.

[0014] Specifically, the negative pressure automatic control system is connected to the first discharge pipe and the second discharge pipe. The negative pressure automatic control system stabilizes the solid-liquid separation device within a set negative pressure range. The gas in the solid-liquid separation device is discharged through the first discharge pipe, and the clear liquid is discharged through the second discharge pipe.

[0015] Optionally, the first cylinder is arranged above the first cone, and the first cylinder is connected to the first cone; one end of the feed pipe is inserted below the slurry in the reactor, and the other end is arranged inside the first cone and connected to the first cone; one end of the sedimentation pipe is inserted below the slurry in the reactor, and the other end is connected to the bottom of the first cone; the first discharge pipe is arranged at the top of the first cylinder, and the first discharge pipe is provided with a first valve.

[0016] Optionally, the second cylinder is arranged above the second cone, and the second cylinder is connected to the second cone; one end of the clear liquid suction pipe is inserted below the liquid level of the clear liquid tank, and the other end is connected to the bottom of the second cone; the second discharge pipe is arranged at the top of the second cylinder, and the second discharge pipe is provided with a second valve, and the clear liquid suction pipe is provided with a third valve.

[0017] Optionally, one end of the feed pipe close to the first cone is arranged above the settling pipe and extends vertically downward or tangent to the first cylinder.

[0018] Specifically, when one end of the feed pipe is arranged above the sedimentation pipe and vertically downward, it can bring kinetic energy to the fluid in the sedimentation pipe and accelerate the falling back of the solid particles therein; when one end of the feed pipe is tangent to the first cylinder, the feed slurry enters the first cylinder tangentially and swirls downward along the wall of the first cylinder, which can flush the solid particles deposited on the inner wall of the first cone into the sedimentation pipe, and also accelerate the liquid flow rate in the sedimentation pipe.

[0019] Optionally, an exhaust pipe is provided in the horizontal section of the feed pipe, and a fourth valve is provided on the exhaust pipe; one end of the exhaust pipe is connected to the feed pipe, and the other end is connected to the first exhaust pipe to exhaust the gas in the feed pipe.

[0020] Specifically, by providing an exhaust pipe in the horizontal section of the feed pipe, the gas in the feed pipe is discharged to prevent gas from remaining in the feed pipe.

[0021] Optionally, the slope angles of the first cone and the second cone are greater than the angle of repose of the solid particles in the slurry, so as to facilitate the downward sliding of the solid particles.

[0022] Specifically, the slope angles of the first cone and the second cone are greater than the angle of repose of the solid particles in the slurry, enabling the solid particles to automatically slide into the settling pipe or the clear liquid suction pipe.

[0023] According to another aspect of the present application, the present application also provides a solid-liquid separation method, which uses the above-mentioned solid-liquid separation device and includes the following steps:

[0024] (1) Open all the valves of the solid-liquid separation device, and turn on the negative pressure automatic control system. Suction the slurry in the reactor into the first cylinder, and transport the liquid in the clear liquid tank to the second cylinder to fill the solid-liquid separation device. Then close the third valve on the clear liquid suction pipe and the fourth valve on the exhaust pipe.

[0025] (2) Under the interception of the intermediate diaphragm, the solid particles in the slurry are intercepted inside the first cylinder. Under the action of gravity, the solid particles settle to the first cone and return to the reactor through the settling pipe, while the clear liquid in the slurry enters the second cylinder through the intermediate diaphragm and then is discharged from the solid-liquid separation device.

[0026] Specifically, in step (1), the slurry is suctioned into the first cylinder through the action of negative pressure, and the clear liquid is suctioned or pressed into the second cylinder through the action of negative pressure or positive pressure.

[0027] Specifically, in step (2), due to the higher solid concentration in the first cone and the settling pipe and the lower solid concentration in the reactor and the feed pipe, with the slurry density difference as the driving force, a directional circulating flow is formed among the settling pipe, the reactor, and the feed pipe to prevent the solids in the first cone from clogging in the settling pipe and enabling the solid particles to automatically return to the reactor; under the action of the formed thin filter cake, the intermediate diaphragm intercepts the solid particles that are larger than or even partially much smaller than the pore size of the intermediate diaphragm in the first cylinder. The fine particles smaller than the pore size of the intermediate diaphragm will settle to the second cone in the second cylinder and are discharged through the third valve and returned to the reactor, achieving an improvement in separation accuracy.

[0028] Optionally, it further includes step (3) of opening the fourth valve on the exhaust pipe to discharge the gas in the feed pipe.

[0029] Specifically, for processes involving gas participation or gas generation, it further includes step (3) of opening the fourth valve on the exhaust pipe to discharge the gas in the feed pipe.

[0030] Optionally, it further includes step (4) of closing the first valve on the first discharge pipe and the second valve on the second discharge pipe, opening the third valve on the clear liquid suction pipe, and transporting the liquid in the clear liquid tank into the second cylinder body to backwash the intermediate diaphragm, so that the solid particles on the intermediate diaphragm are separated from the intermediate diaphragm and return to the reactor through the settling pipe.

[0031] Specifically, if the intermediate diaphragm is blocked, it further includes the step of backwashing the intermediate diaphragm, that is, step (4) of closing the first valve on the first discharge pipe and the second valve on the second discharge pipe, opening the third valve on the clear liquid suction pipe, and transporting the liquid in the clear liquid tank into the second cylinder body to backwash the intermediate diaphragm, so that the solid particles on the intermediate diaphragm are separated from the intermediate diaphragm and return to the reactor through the settling pipe to solve the problem of poor circulation caused by the blockage of the intermediate diaphragm.

[0032] According to another aspect of the present application, there is also provided the application of the above solid-liquid separation device or the above solid-liquid separation method in microbial fermentation, solid catalytic reaction or reaction crystallization process.

[0033] Specifically, the solid-liquid separation device and the solid-liquid separation method provided by the present application have a wide range of applications and can be applied to the continuous separation of micro-nano solid particles and liquid in a reaction system with a solid content of not more than 80 wt.%.

[0034] The beneficial effects of the present application include but are not limited to:

[0035] 1. According to the solid-liquid separation device of the present application, by setting a solid phase settling unit, a clear liquid discharge unit, an intermediate diaphragm, a negative pressure automatic control system and a clear liquid storage tank, the combination of gravity settling and intermediate diaphragm filtration can achieve high-precision solid-liquid separation, and at the same time, it is not easy to cause blockage and damage to solid particles.

[0036] 2. According to the solid-liquid separation device of the present application, when the intermediate diaphragm has poor circulation, the clear liquid in the clear liquid tank can be pumped reversely into the second cylinder body through the clear liquid suction pipe to backwash the intermediate diaphragm. This process does not require the introduction of an additional backwashing device, saving operating costs.

[0037] 3. According to the solid-liquid separation device of the present application, the combination of gravity settling and the intermediate diaphragm enables the slurry to be transported to an external separation device without passing through a pump. Therefore, solid particles such as microorganisms and catalysts will not be damaged by the pump, and it is possible to achieve non-damaging and efficient interception of micro-nano catalysts and microorganisms, as well as adjustment of the particle size and improvement of the morphology of reaction crystallization products.

[0038] 4. According to the solid-liquid separation method of the present application, the operation steps are simple, environmentally friendly, and convenient for large-scale promotion. Description of the Drawings

[0039] The accompanying drawings described herein are used to provide a further understanding of the present application and form a part of the present application. The schematic embodiments of the present application and their descriptions are used to explain the present application and do not constitute an improper limitation to the present application. In the drawings:

[0040] Figure 1 is a front view sectional structure schematic diagram of the solid-liquid separation device adopted in Embodiment 1 of the present invention;

[0041] Figure 2 is an SEM image of the precursor particles in Embodiment 1 of the present invention;

[0042] Figure 3 is a front view sectional structure schematic diagram of the solid-liquid separation device adopted in Embodiments 2 and 3 of the present invention;

[0043] Figure 4 is a front view sectional structure schematic diagram of the solid-liquid separation device adopted in Embodiment 4 of the present invention;

[0044] Figure 5 is an SEM image of the precursor particles in Comparative Example 1 of the present invention.

[0045] List of components and reference numerals:

[0046] 1. Feed pipe; 2. First cone; 3. First cylinder; 4. Settling pipe; 5. Exhaust pipe; 6. First discharge pipe; 7. Intermediate diaphragm; 8. Clear liquid tank; 9. Clear liquid suction pipe; 10. Second cone; 11. Second cylinder; 12. Second discharge pipe; 13. Negative pressure automatic control system; 14. Clear liquid storage tank; 15. First valve; 16. Second valve; 17. Third valve; 18. Fourth valve. Detailed embodiments

[0047] The present application will be described in detail below with reference to the embodiments, but the present application is not limited to these embodiments.

[0048] Unless otherwise specified, the raw materials in the embodiments and comparative examples of the present application are purchased through commercial channels.

[0049] Unless otherwise specified, the methods adopted in the embodiments and comparative examples of the present application are conventional methods in the prior art.

[0050] Embodiment 1

[0051] Taking the production of ternary lithium battery precursor NCM811 as an example in Embodiment 1, the reactor is a stirred tank, the intermediate diaphragm 7 is a nylon filter with a pore size of 3 μm, nickel cobalt manganese mixed sulfate solution (where the molar ratio of nickel, cobalt, and manganese elements is 8:1:1), ammonia water, and sodium hydroxide solution continuously enter the stirred tank, and the ammonia water and pH value in the reaction kettle are controlled to be maintained within a stable range. The nickel, cobalt, and manganese elements undergo a coprecipitation reaction in the stirred tank to crystallize into micron-sized precursor Ni0.8 Co 0.1 Mn 0.1 (OH)2 particles, and the solid-liquid separation device used is as Figure 1 shown.

[0052] As Figure 1 shown, the solid-liquid separation device includes a solid-phase sedimentation unit, a clear liquid discharge unit, an intermediate diaphragm 7, a negative pressure automatic control system 13, and a clear liquid storage tank; the solid-phase sedimentation unit includes a feed pipe 1, a first cone 2, a first cylinder 3, a sedimentation pipe 4, and a first discharge pipe 6; the clear liquid discharge unit includes a clear liquid tank 8, a clear liquid suction pipe 9, a second cone 10, a second cylinder 11, and a second discharge pipe 12; the intermediate diaphragm 7 is arranged between the first cylinder 3 and the second cylinder 11; the negative pressure automatic control system 13 is communicated with the first discharge pipe 6 and the second discharge pipe 12; the clear liquid storage tank 14 is arranged on one side of the negative pressure automatic control system 13 away from the second cylinder 11; the first cylinder 3 is arranged above the first cone 2, and the first cylinder 3 is communicated with the first cone 2; one end of the feed pipe 1 is inserted below the slurry in the reactor, and the other end is arranged inside the first cone 2 and communicated with the first cone 2; one end of the sedimentation pipe 4 is inserted below the slurry in the reactor, and the other end is communicated with the bottom of the first cone 2; the first discharge pipe 6 is arranged on the top of the first cylinder 3, and a first valve 15 is arranged on the first discharge pipe 6; the second cylinder 11 is arranged above the second cone 10, and the second cylinder 11 is communicated with the second cone 10; one end of the clear liquid suction pipe 9 is inserted below the liquid level of the clear liquid tank 8, and the other end is communicated with the bottom of the second cone 10; the second discharge pipe 12 is arranged on the top of the second cylinder 11, a second valve 16 is arranged on the second discharge pipe 12, and a third valve 17 is arranged on the clear liquid suction pipe 9; one end of the feed pipe 1 close to the first cone 2 is arranged above the sedimentation pipe 4 and vertically downward; an exhaust pipe 5 is arranged on the horizontal section of the feed pipe 1, and a fourth valve 18 is arranged on the exhaust pipe 5; one end of the exhaust pipe 5 is communicated with the feed pipe 1, and the other end is communicated with the first discharge pipe 6 to discharge the gas in the feed pipe 1; the slope angles of the first cone 2 and the second cone 10 are greater than the stacking angle of the NCM811 precursor solid particles to facilitate the downward sliding of the solid particles.

[0053] In this embodiment, the solid-liquid separation method includes the following steps:

[0054] Before the reaction starts, first add the reaction bottom liquid to the specified height in the reactor stirring tank and the clear liquid tank 8, fully open the valves on the solid-liquid separation device, turn on the negative pressure automatic control system 13, and fill the solid-liquid separation device with the reaction bottom liquid under the siphon effect, so that there is liquid communication inside the reactor stirring tank and the clear liquid storage tank 14 and the liquid levels are kept at the same horizontal line, and then close the third valve 17 on the clear liquid suction pipe 9 and the fourth valve 18 on the exhaust pipe 5 to keep the inside of the solid-liquid separation device within a stable negative pressure range;

[0055] Since there is liquid communication between the reactor stirring tank and the supernatant storage tank 14, in order to keep the liquid levels even, under the action of the principle of communicating vessels, the slurry in the reaction kettle enters the first cylinder 3 through the feed pipe 1 and the settling pipe 4. Under the interception of the middle diaphragm 7, solid particles are intercepted in the first cylinder 3. Due to the slowdown of the flow rate, solid particles settle into the first cone 2 and the settling pipe 4 and return to the reactor stirring tank. The supernatant and a very small amount of small particles smaller than the pore diameter of the middle diaphragm 7 will pass through the middle diaphragm 7 into the second cylinder 11, where the small particles continue to settle into the second cone 10. At the same time, the supernatant will overflow into the supernatant storage tank 14. In the initial stage of operation, the third valve 17 on the supernatant suction pipe 9 is regularly opened to return the small particles to the reactor.

[0056] As the reaction proceeds, the solid content in the reactor stirring tank gradually increases. To prevent a large amount of solid particles from depositing in the first cone 2, the slope angles of the first cone 2 and the second cone 10 are designed to be greater than the stacking angle of NCM811 precursor particles, so that after a certain amount of precursor particles are stacked, they can automatically slide down into the settling pipe 4. Gradually, the slurry density in the settling pipe 4 is greater than the slurry density in the stirring tank and the feed pipe 1. Under the action of the density difference, the slurry forms a directional circulating flow between the settling pipe 4, the stirring tank and the feed pipe 1. The slurry is vertically ejected downward from the feed pipe 1, bringing kinetic energy to the fluid in the settling pipe 4 and accelerating the automatic return of the particles in the settling pipe 4 to the stirring tank.

[0057] Since nitrogen is continuously introduced into the reactor stirring tank as a protective gas, under the high-speed stirring of the stirring paddle, the slurry will carry a part of the gas into the solid-liquid separation device, resulting in a decrease in the negative pressure in the first cylinder 3. When it is lower than the set negative pressure value, the negative pressure automatic control system 13 will automatically start working to extract the gas in the solid-liquid separation device. To prevent gas in the feed pipe 1, the fourth valve 18 on the exhaust pipe 5 is regularly opened to evacuate the gas in the feed pipe 1 and the exhaust pipe 5.

[0058] In this embodiment, a nickel-cobalt-manganese sulfate mixed solution is prepared according to a target solid content of 80 wt.%. After 56 hours of the experiment, it is not found that the middle diaphragm 7 is blocked. The actually measured solid content in the reactor stirring tank is 75 wt.%. The morphology of the prepared NCM811 precursor is as Figure 2 shown. As can be seen from Figure 2 it, its sphericity is good, indicating that after concentration using the solid-liquid separation device of the present invention, the product morphology can be significantly improved. After being doped with lithium and sintered to make a button cell, its 1C discharge specific capacity is 190.8 mAh / g, and the capacity retention rate after 200 cycles is 93.3%, which is more than 10% higher than that of commercial similar cathode materials, indicating a significant improvement in product quality.

[0059] Example 2

[0060] Example 2 Taking the process of yeast fermentation to produce single-cell protein as an example, the reactor is an internal-loop slurry bed reactor. Since the diameter d of yeast during fermentation in this example is 10 between 1 - 30 μm, the intermediate diaphragm 7 used in this example is a plastic film with a pore diameter of 0.5 μm, which can prevent most yeast from being discharged from the internal-loop slurry bed reactor; the solid-liquid separation device used is as Figure 3 shown.

[0061] As Figure 3 shown, the difference between the solid-liquid separation device used in this example and that in Example 1 is that the clear liquid in this example is not discharged from the internal-loop slurry bed reactor by the principle of the communicating vessel, but is pumped out of the internal-loop slurry bed reactor at a constant speed under the action of the pump in the negative pressure automatic control system 13. Therefore, it is not necessary to maintain the liquid levels in the clear liquid storage tank 14 and the internal-loop slurry bed reactor at the same level, and the rest are the same.

[0062] In this example, the solid-liquid separation method includes the following steps:

[0063] Before the reaction starts, first add the culture medium to the specified height in the internal-loop slurry bed reactor and the clear liquid tank 8, fully open all the valves on the solid-liquid separation device, turn on the negative pressure automatic control system 13, and under the action of the pump, lift the culture medium in the clear liquid tank 8 and the internal-loop slurry bed reactor upward to fill the solid-liquid separation device. Then close the third valve 17 on the clear liquid suction pipe 9 and the fourth valve 18 on the exhaust pipe 5 to keep the inside of the solid-liquid separation device within a stable negative pressure range;

[0064] Add yeast to the internal-loop slurry bed reactor, and at the same time pump fresh culture medium into the internal-loop slurry bed reactor at a constant flow rate. The yeast continuously ferments in the internal-loop slurry bed reactor with the culture medium as the nutrient; the fermentation broth enters the first cylinder 3 through the settling tube 4 and the feed pipe 1 under the action of the negative pressure control system 13. Under the interception of the intermediate diaphragm 7, the yeast is intercepted in the first cylinder 3; due to the slowdown of the flow rate, the yeast gradually settles into the first cone 2 and the settling tube 4 under the action of gravity and returns to the internal-loop slurry bed reactor. The old culture medium containing harmful metabolites in the first cylinder 3 enters the second cylinder 11 through the intermediate diaphragm 7 and enters the clear liquid storage tank 14 under the action of the negative pressure control system 13.

[0065] As the fermentation progresses, the yeast content in the internal-loop slurry bed reactor gradually increases. To prevent a large amount of yeast from depositing in the first cone 2, the slope angles of the first cone 2 and the second cone 10 are designed to be greater than the angle of repose of the yeast, so that after a certain amount of yeast accumulates, it can automatically slide down into the settling tube 4; gradually, the slurry density in the settling tube 4 is greater than that in the stirring kettle and the feed pipe 1. Under the action of the density difference, the slurry forms a directional circulating flow between the settling tube 4, the stirring kettle, and the feed pipe 1. The slurry is ejected vertically downward from the feed pipe 1, bringing kinetic energy to the fluid in the settling tube 4 and accelerating the automatic return of the yeast in the settling tube 4 to the internal-loop slurry bed reactor.

[0066] Due to continuous aeration during the fermentation process, a part of the gas will be brought into the solid-liquid separation device by the fermentation broth, resulting in a decrease in the negative pressure in the first cylinder 3. When it is lower than the set negative pressure value, the negative pressure automatic control system 13 will automatically start working to extract the gas in the solid-liquid separation device; to prevent gas in the feed pipe 1, the valve on the exhaust pipe 5 is regularly opened to empty the gas in the feed pipe 1 and the exhaust pipe 5.

[0067] In this embodiment, the fermentation process lasts for 12 days. When the fermentation proceeds to the 6th day, the yeast adsorbs on the intermediate membrane 7, increasing the resistance of the clear liquid passing through the intermediate membrane 7. Close the first valve 15 on the first discharge pipe 6 and the second valve 16 on the second discharge pipe 12, and open the third valve 17 on the clear liquid suction pipe 9 to pump the fresh culture medium in the clear liquid tank 8 into the second cylinder 11 to backwash the intermediate membrane 7, and the yeast adsorbed on it can be effectively washed off and fall back into the settling tube 4 and return to the internal-loop slurry bed reactor. After the fermentation ends, the cell dry weight in the fermentation product is measured to be as high as 60 g / L.

[0068] Example 3

[0069] The difference between Example 3 and Example 2 is that the intermediate membrane 7 is a ceramic membrane with a pore size of 0.5 μm, and the culture medium is replaced with normal saline to maintain the cell activity of the yeast, and the rest are the same, so as to investigate the influence of the solid-liquid separation device on the microbial activity.

[0070] The experiment lasts for 24 hours. After the experiment ends, the viable cell count is examined by the spread plate method, and the viable cell activity retention rate is 90%.

[0071] Example 4

[0072] Example 4 is to simulate a solid catalytic reaction, with brown fused alumina-water as the model reaction system, and the reactor is a stirred tank. A cold model experiment is carried out in the stirred tank; the d 10 of brown fused alumina is 9 μm. Therefore, in this embodiment, the intermediate membrane 7 is a sand-like filter membrane with a pore size of 5 μm to prevent solid particles from escaping.

[0073] The structure of the solid-liquid separation device adopted in this embodiment is as follows Figure 4 shown. The difference between the solid-liquid separation device in Embodiment 4 and that in Embodiment 2 is that since there is no gas participation and no gas is generated during the experimental process of this embodiment, the first discharge pipe 6 and the second discharge pipe 12 are combined and controlled by the same set of negative pressure automatic control system 13; in addition, the material in the feed pipe 1 enters the first cylinder 3 tangentially in this embodiment.

[0074] In this embodiment, the solid-liquid separation method includes the following steps:

[0075] Before the experiment starts, all the valves on the solid-liquid separation device are opened, and clear water is pumped into it; then, the third valve 17 on the clear liquid suction pipe 9 and the fourth valve 18 on the exhaust pipe 5 are closed, and brown fused alumina particles are added to the reactor stirring tank to make the solid content of the slurry therein 35 wt.%. Under the suction of the pump in the negative pressure automatic control system 13, the slurry tangentially enters the first cylinder 3 from the reactor stirring tank. The slurry forms a swirl in the first cylinder 3, washing the solid particles deposited on the inner wall of the first cone 2 into the settling pipe 4, accelerating the fluid flow in the settling pipe 4. Other solid-liquid separation processes are similar to those in Embodiment 2 and will not be elaborated here. Since a small amount of gas may enter the horizontal section of the feed pipe 1 due to the low-speed stirring of the stirring paddle, in order to prevent the liquid in the feed pipe 1 from being discontinuous, the valve on the exhaust pipe 5 is opened irregularly to discharge the gas in the pipeline.

[0076] The experiment lasts for 1000 hours, and a backwashing operation is carried out every 200 hours in the middle to prevent solid particles from blocking the intermediate diaphragm 7 and affecting the stable operation of the solid-liquid separation device.

[0077] After the experiment ends, the solid content is measured to be 20 mg / L by sampling in the second cone 10. It can be seen that under the action of the solid-liquid separation device and the solid-liquid separation method proposed in this application, most of the solid particles can be intercepted in the reactor, and the solid-liquid separation device and the solid-liquid separation method proposed in this application are applicable to solid catalytic reactions.

[0078] Embodiment 5

[0079] The difference between Embodiment 5 and Embodiment 4 is that in this embodiment, the intermediate diaphragm 7 is a filter screen made of metal material, and the rest are the same.

[0080] Comparative Example 1

[0081] The difference between Comparative Example 1 and Embodiment 1 is that Comparative Example 1 adopts the device and method shown in the patent with the application number 202010855068.3. At the end of the reaction, the solid content in the kettle is 52 wt.%, and the precursor morphology is as follows Figure 5As shown in the figure. After doping with lithium and sintering, it is made into a button cell, with a 1C discharge specific capacity of 166.8 mAh / g and a capacity retention rate of 81.6% after 200 cycles.

[0082] It can be seen from this that the solid-liquid separation device and method proposed in the present invention are applied to the reaction crystallization process. On the one hand, it can increase the solid content rate in the reactor, thereby improving the sphericity of crystals; on the other hand, due to the improvement of crystal morphology, the electrochemical performance of the crystal material is also greatly improved.

[0083] Comparative Example 2

[0084] The difference between Comparative Example 2 and Example 2 is that Comparative Example 2 is an off-reactor separation method, that is, the fermentation broth is pumped out of the reactor and filtered in an off-reactor hollow membrane filtration device, and then the yeast is transported back into the reactor. The fermentation conditions are the same as those in Example 2. After 12 days of fermentation, the dry cell weight in the sampled fermentation broth was measured to be 45 g / L.

[0085] Comparative Example 3

[0086] The difference between this comparative example and Example 3 is that this comparative example is an off-reactor separation method, that is, the mixture of yeast and physiological saline is pumped out of the reactor and filtered in an off-reactor hollow membrane filtration device, and then the yeast is transported back into the reactor. Other conditions are the same as those in Example 3. After the experiment, the viable count was examined by the spread plate method, and the yeast activity retention rate was 70%.

[0087] As can be seen from the above, when the off-reactor separation method is used, the yeast will be damaged to a certain extent under the transportation of the pump, resulting in partial loss of its activity; while using the device and method proposed in the present invention for fermentation, the microorganisms can be in-situ separated and returned without passing through the pump, without damage to the microorganisms, and can significantly improve the viable count and the yield of dry cell weight during the fermentation process.

[0088] As described above, only the embodiments of the present application are concerned. The protection scope of the present application is not limited by these specific embodiments, but is determined by the claims of the present application. For those skilled in the art, various changes and modifications can be made to the present application. Any modification, equivalent replacement, improvement, etc. made within the technical idea and principle of the present application shall be included within the protection scope of the present application.

Claims

1. A solid-liquid separation device, characterized in that, It includes a solid-phase sedimentation unit, a clear liquid discharge unit, an intermediate diaphragm, a negative-pressure automatic control system, and a clear liquid storage tank; The solid-phase sedimentation unit includes a feed pipe, a first cone, a first cylinder, a sedimentation pipe, and a first discharge pipe; the clear liquid discharge unit includes a clear liquid tank, a clear liquid suction pipe, a second cone, a second cylinder, and a second discharge pipe; the intermediate diaphragm is arranged between the first cylinder and the second cylinder; the negative-pressure automatic control system is communicated with the first discharge pipe and the second discharge pipe; the clear liquid storage tank is arranged on one side of the negative-pressure automatic control system away from the second cylinder.

2. The solid-liquid separation device according to claim 1, characterized in that, The first cylinder is arranged above the first cone, and the first cylinder is communicated with the first cone; one end of the feed pipe is inserted below the slurry in the reactor, and the other end is arranged inside the first cone and communicated with the first cone; one end of the sedimentation pipe is inserted below the slurry in the reactor, and the other end is communicated with the bottom of the first cone; the first discharge pipe is arranged on the top of the first cylinder, and a first valve is arranged on the first discharge pipe.

3. The solid-liquid separation device according to claim 1, characterized in that, The second cylinder is arranged above the second cone, and the second cylinder is communicated with the second cone; one end of the clear liquid suction pipe is inserted below the liquid level of the clear liquid tank, and the other end is communicated with the bottom of the second cone; the second discharge pipe is arranged on the top of the second cylinder, a second valve is arranged on the second discharge pipe, and a third valve is arranged on the clear liquid suction pipe.

4. The solid-liquid separation device according to claim 2, characterized in that One end of the feed pipe close to the first cone is arranged above the sedimentation pipe and vertically downward or tangent to the first cylinder.

5. The solid-liquid separation device according to claim 4, wherein, An exhaust pipe is arranged on the horizontal section of the feed pipe, and a fourth valve is arranged on the exhaust pipe; one end of the exhaust pipe is communicated with the feed pipe, and the other end is communicated with the first discharge pipe to discharge the gas in the feed pipe.

6. The solid-liquid separation device according to claim 1, characterized in that, The slope angles of the first cone and the second cone are greater than the stacking angle of the solid particles in the slurry to facilitate the downward sliding of the solid particles.

7. A solid-liquid separation method, characterized in that, Using the solid-liquid separation device according to any one of claims 1 to 6, it includes the following steps: (1) Open all the valves of the solid-liquid separation device, and turn on the negative-pressure automatic control system to suck the slurry in the reactor into the first cylinder and transport the liquid in the clear liquid tank to the second cylinder to fill the solid-liquid separation device, and then close the third valve on the clear liquid suction pipe and the fourth valve on the exhaust pipe; (2) Under the interception of the intermediate diaphragm, the solid particles in the slurry are intercepted inside the first cylinder. Under the action of gravity, the solid particles settle to the first cone and return to the reactor through the sedimentation pipe, while the clear liquid in the slurry enters the second cylinder through the intermediate diaphragm and then is discharged from the solid-liquid separation device.

8. The solid-liquid separation method according to claim 7, characterized in that, It also includes step (3) opening the fourth valve on the exhaust pipe to discharge the gas in the feed pipe.

9. The solid-liquid separation method according to claim 7, wherein, It also includes step (4) closing the first valve on the first discharge pipe and the second valve on the second discharge pipe, opening the third valve on the clear liquid suction pipe, and transporting the liquid in the clear liquid tank into the second cylinder to backwash the intermediate diaphragm so that the solid particles on the intermediate diaphragm are separated from the intermediate diaphragm and return to the reactor through the sedimentation pipe.

10. Use of the solid-liquid separation device according to any one of claims 1 to 6 or the solid-liquid separation method according to any one of claims 7 to 9 in microbial fermentation, solid catalytic reaction or reaction crystallization processes.

Images