A rotating impeller, an aeration device, and a rotating impeller aerated bioreactor

Abstract

This invention provides a rotating impeller comprising a base plate and a cover plate arranged coaxially and spaced apart vertically. Between the cover plate and the base plate, a gas-liquid mixing chamber and a gas-liquid flow channel chamber are formed sequentially from the inside out, centered on the axis. A gas guiding structure extends into the gas-liquid mixing chamber. Multiple liquid inlets are provided on the base plate within the gas-liquid mixing chamber. A gas-liquid outlet is formed between the outer edges of the base plate and the cover plate. Multiple gas-liquid flow channels are formed in the gas-liquid flow channel chamber by several partitions, evenly distributed around the axis. Each gas-liquid flow channel contains one or more of the following: a flow splitting and constriction structure, a secondary acceleration and expansion structure, and a microchannel mixing and shearing structure. This invention provides an aeration device and a bioreactor incorporating the aforementioned rotating impeller. Using the solution of this invention, fresh gas reaches the rotating impeller and generates microbubbles. The structure is simple and the cost is low. It is not limited to bioreactors and can also be used for reactions in general gas-liquid two-phase and gas-liquid-solid three-phase systems.

Description

Technical Field

[0001] This invention belongs to the field of biochemical technology, specifically relating to a rotating impeller, an aeration device, and a rotating impeller aeration bioreactor. Background Technology

[0002] Multiphase reactors are widely used in various industries, especially in the biochemical industry. The efficiency of multiphase reactors is crucial to product quality and cost, and sometimes directly reflects the success of a process route. Currently, there are various types of multiphase reactors, such as Venturi reactors, trickle bed reactors, bubble reactors, high-gravity bed reactors, and microchannel reactors, all of which share the common goal of increasing the mass transfer efficiency between phases.

[0003] Due to their unique characteristics, multiphase bioreactors have higher structural requirements and constraints. For gas-liquid and gas-liquid-solid multiphase reactions, designers must consider both mass transfer efficiency and reactor aseptic requirements. Therefore, most current biological reactions exhibit low mass transfer efficiencies in both gas-liquid and gas-liquid-solid processes. However, the advent of micro-interface mass transfer enhancement technology has revolutionized bioreactors. New types of reactors, such as Venturi microbubble reactors, hypergravity field microbubble reactors, dynamic membrane microbubble reactors, and microchannel reactors, have emerged, solving the mass transfer efficiency issues in both gas-liquid and gas-liquid-solid processes. However, the application of some new reactors (such as Venturi microbubble reactors, hypergravity field microbubble reactors, and microchannel reactors) is limited by the requirements for pure microbial culture.

[0004] Currently, most bioreactors utilize aeration methods such as dynamic membrane aeration and multi-layer shear microporous aeration, with relatively good results. However, while dynamic membrane aeration can solve clogging problems and extend service life, the transmembrane pressure increases with operating time, thereby reducing the airflow per unit membrane area and increasing inlet pressure, thus raising operating costs. Multi-layer shear microporous aeration, due to its multi-layer shearing mechanism, inherently increases motor power, further raising operating costs, and is also unsuitable for shear-sensitive systems.

[0005] In summary, there is an urgent need to design a bioreactor that can generate microbubbles, be used in multiple systems, and operate for a long time for highly aerobic, C1 gas, and biomass gas fermentation systems. Summary of the Invention

[0006] To address the aforementioned problems, this invention provides a rotating impeller, an aeration device, and a rotating impeller aerated bioreactor. Due to the unique internal structure of the rotating impeller, suitable impeller structures can be selected for different fermentation systems, greatly expanding its application range. This invention also provides an aeration device with this rotating impeller and a rotating impeller aerated bioreactor using this aeration device. This reactor uses an external power source to control the rotational speed of the rotating impeller, allowing for flexible adjustment of the impeller speed for different systems. This reactor features good gas-liquid mixing, simple structure, convenient maintenance, and flexible operation.

[0007] To achieve the above objectives, the present invention adopts the following technical solution:

[0008] A rotating impeller includes a base plate and a cover plate arranged coaxially and spaced apart vertically. Between the cover plate and the base plate, a gas-liquid mixing chamber and a gas-liquid flow channel chamber are formed from the inside to the outside with the axis as the center. A gas guiding structure extends into the gas-liquid mixing chamber. Multiple liquid inlets are provided on the base plate located within the gas-liquid mixing chamber. A gas-liquid outlet is formed between the outer edges of the base plate and the cover plate. Multiple gas-liquid flow channels are formed in the gas-liquid flow channel chamber by several partitions, which are evenly distributed around the axis. Each gas-liquid flow channel is provided with one or more of the following: a flow splitting and constriction structure, a secondary acceleration and expansion structure, and a microchannel mixing and shearing structure.

[0009] Furthermore, a liquid guide wheel is provided at the bottom of the gas-liquid mixing chamber, and the liquid guide wheel is fixed to the lower end of the gas guiding structure; the number of guide impellers on the liquid guide wheel is 4, 6, 8, 12, 16 or 24, preferably 6, 8, 12 or 16.

[0010] Furthermore, the rotating impeller also includes a mandrel seat formed in the middle of the upper surface of the cover plate, and a mounting hole extending axially downward from the upper surface of the mandrel seat to the lower surface of the base plate. The air guiding structure passes through the mounting hole and is connected to the rotating impeller. The height of the gas-liquid mixing chamber in the axial direction is greater than the height of the gas-liquid flow channel chamber in the axial direction.

[0011] Furthermore, the partition includes multiple first planar partitions and multiple second planar partitions, all arranged in a circular pattern around an axis and alternately spaced at equal intervals. The length of the first planar partition is greater than the length of the second planar partition. The first planar partition penetrates the gas-liquid flow channel chamber in the radial direction, and the outer side of the second planar partition extends to the outer edge of the cover plate in the radial direction. Two adjacent first planar partitions, the bottom plate, and the cover plate form a gas-liquid flow channel. In the gas-liquid flow channel, a diversion and constriction structure and a secondary acceleration and expansion structure are provided from the inside to the outside. The diversion and constriction structure is a crescent-shaped structural block with the concave surface facing outward. The secondary acceleration and expansion structure consists of two first square bending blocks with the inner folding surface facing outward and two second square bending blocks with the inner folding surface facing outward. The two first square bending blocks and the two second square bending blocks are mirror-symmetrically arranged on both sides of the second planar partition. The first square bending blocks are located inside the second square bending blocks, and the outermost edge of the second square bending blocks is adjacent to the outer edge of the cover plate.

[0012] Furthermore, the partition includes multiple first arc-shaped partitions evenly distributed in a circle around the axis. One end of the first arc-shaped partition is located at the outer edge of the cover plate, and the other end is located on the inner ring line of the gas-liquid flow channel chamber. Two adjacent first arc-shaped partitions, the bottom plate, and the cover plate form a gas-liquid flow channel. In the gas-liquid flow channel, a diversion and constriction structure and a secondary acceleration and expansion structure are arranged sequentially from the inside to the outside. The diversion and constriction structure is an arrow-shaped structural block with its tip pointing inward. The secondary acceleration and expansion structure is a triangular structural block with its tip pointing towards the arrow-shaped structural block. The outer side of the triangular structural block is located at the outer edge of the cover plate. Two shearing blocks are mirror-symmetrically arranged on the inner sides of two adjacent first arc-shaped partitions.

[0013] Furthermore, the partition includes multiple V-shaped partitions that are evenly distributed in a circle around the axis and have an interior angle greater than 90°. One end of the V-shaped partition is located at the outer edge of the cover plate, and the other end is located on the inner ring line of the gas-liquid flow channel chamber. Two adjacent V-shaped partitions, the bottom plate, and the cover plate form a gas-liquid flow channel. Two secondary acceleration and expansion structures are arranged sequentially from the inside to the outside in the gas-liquid flow channel. The two secondary acceleration and expansion structures are two polygonal structural blocks with different shapes. Both ends of the two polygonal structural blocks along the extension direction of the gas-liquid flow channel are pointed.

[0014] Furthermore, the partition includes multiple second arc-shaped partitions evenly distributed in a circle around the axis. One end of the second arc-shaped partition is located at the outer edge of the cover plate, and the other end is located on the inner ring line of the gas-liquid flow channel chamber. Multiple semi-heart-shaped grooves are equally spaced along the arc direction on both sides of the second arc-shaped partition. The semi-heart-shaped grooves on the opposite sides of two adjacent second arc-shaped partitions are arranged opposite each other. Two adjacent second arc-shaped partitions, the bottom plate, and the cover plate form a gas-liquid flow channel with a microchannel heart-shaped hybrid shear structure.

[0015] An aeration device, characterized in that the aeration device includes a motor, a magnetic fluid seal, a hollow shaft, and a rotating impeller. An air inlet is provided on the upper side wall of the hollow shaft, and the upper end of the hollow shaft is connected to an external air source through the magnetic fluid seal. The motor is connected to the hollow shaft through a coupling frame. The rotating impeller is the rotating impeller as described in claims 1 to 7. The lower end of the hollow shaft is fixed to the rotating impeller, and the air outlet located on the lower side wall of the hollow shaft is located in the gas-liquid mixing chamber.

[0016] A rotary impeller aerated bioreactor, characterized in that it comprises a tank, a stirring device, and an aeration device as described in claim 8; the tank is provided with an air outlet and a material outlet; the stirring device is fixed to the tank; the aeration device is obliquely fixed to the lower side wall of the tank via a tank connecting pipe provided on the hollow shaft; the lower part of the hollow shaft and the rotary impeller are located inside the tank; the angle between the central axis of the aeration device and the horizontal plane is θ, where θ = 15~90°. 0 Preferably 30 0 45 0 60 0 and 75 0 .

[0017] Furthermore, the angle θ between the central axis of the aeration device and the horizontal plane is 30°. 0 45 0 60 0 and 75 0 .

[0018] Compared with the prior art, the present invention has the following beneficial effects:

[0019] 1. This invention uses a rotating impeller gas distributor to generate microbubbles with a large specific surface area, which increases the gas-liquid contact area and greatly improves the mass transfer efficiency. At the same time, it avoids the potential risks of increased transmembrane pressure and high inlet pressure and multi-layer microporous shear force caused by long dynamic membrane aeration operation time.

[0020] 2. The gas-liquid reactor in this invention has a simple structure and low cost.

[0021] 3. The gas-liquid reactor of this invention has wide applicability and is not limited to bioreactors. It can also be used for reactions in general gas-liquid two-phase and gas-liquid-solid three-phase systems.

[0022] 4. The independent power system of the rotating impeller of the device allows for arbitrary adjustment of the impeller speed, improving gas utilization and greatly saving production costs.

[0023] 5. Due to the unique structure of the rotating impeller, microbubbles are generated, which greatly improves the gas-liquid mass transfer efficiency, saves production costs, and reduces the harm of toxic and harmful gases to the environment and personnel. Attached Figure Description

[0024] Figure 1 This is a schematic diagram of the structure of the rotating impeller aeration bioreactor described in this invention.

[0025] Figure 2 This is a schematic diagram of the structure of the rotating impeller aeration device with a liquid guide wheel according to the present invention.

[0026] Figure 3 This is a schematic diagram of the structure of the rotating impeller aeration device with a non-liquid guide wheel according to the present invention.

[0027] Figure 4 This is a top view of the rotating impeller described in Example 1.

[0028] Figure 5 This is a top view of the rotating impeller described in Example 2.

[0029] Figure 6 This is a top view of the rotating impeller described in Example 3.

[0030] Figure 7 This is a top view of the rotating impeller described in Example 4.

[0031] Figure 8 This is a top view of the rotating impeller described in Example 6.

[0032] Figure 9 This is a top view of the rotating impeller described in Example 7.

[0033] Figure 10 This is a top view of the rotating impeller described in Example 8.

[0034] Figure 11 This is a top view of the rotating impeller described in Example 9.

[0035] Among them, 1-tank body, 2-heat exchange layer, 3-stirring motor, 4-stirring shaft, 5-stirring impeller, 6-motor, 7-magnetic fluid seal, 8-hollow shaft, 9-rotating impeller, 10-first planar partition, 11-second planar partition, 12-crescent-shaped structural block, 13-first square bent block, 14-second square bent block, 15-first arc-shaped partition, 16-arrow-shaped structural block, 17-triangular structural block, 18-trapezoidal block, 19-V-shaped partition, 22-second arc-shaped partition, 23-tank body connecting pipe, 24-coupling frame, 25- Liquid guide wheel, 251-guide impeller, 221-semi-heart-shaped groove, 1-1-air outlet, 1-2-material outlet, 1-3-perspective mirror, 1-4-manhole, 1-5-sampling port, 1-6-instrument interface, 2-1-steam inlet or cooling water outlet, 2-2-steam condensate outlet or cooling water inlet, 8-1-hollow shaft air inlet, 8-2-hollow shaft air outlet, 9-1-base plate, 9-2-cover plate, 9-3-spindle seat, 9-4-gas-liquid mixing chamber, 9-5-gas-liquid flow channel chamber, 9-6-liquid inlet, 9-7-gas-liquid outlet. Detailed Implementation

[0036] The present invention will now be described in detail with reference to specific embodiments. These embodiments will help those skilled in the art to further understand the present invention, but do not limit the invention in any way. It should be noted that those skilled in the art can make several changes and improvements without departing from the concept of the present invention. These all fall within the protection scope of the present invention. Example 1

[0037] like Figure 1 and Figure 11As shown, a rotary impeller aerated bioreactor includes a tank 1, a stirring device, and an aeration device. An air outlet 1-1, a material outlet 1-2, and a manhole 1-4 are provided on the side wall of the tank 1. A viewing mirror 1-3 and a manhole 1-4 are provided on the top side wall of the tank 1. A sampling port 1-5 and an instrument interface 1-6 are provided on the lower side wall of the tank 1. A heat exchange layer 2 is provided on the outside of the side wall of the tank 1. A steam inlet or cooling water outlet 2-1 and a steam condensate outlet or cooling water inlet 2-2 are provided on the outer side wall of the heat exchange layer 2. The stirring device includes a stirring motor 3, a stirring shaft 4, and multiple stirring impellers 5 spaced axially along the stirring shaft 4. The stirring motor 3 is fixed to the top of the tank 1. Both solid and liquid reactants can enter through the manhole 1-4, or some solid materials can enter through the manhole 1-4. In this embodiment, the aeration device includes a motor 6, a magnetic fluid seal 7, a hollow shaft 8, and a rotating impeller 9. A hollow shaft air inlet 8-1 is provided on the upper side wall of the hollow shaft 8. The upper end of the hollow shaft 8 is connected to an external air source through the magnetic fluid seal 7. The motor 6 is connected to the hollow shaft 8 through a coupling frame 24. The aeration device is obliquely fixed to the lower side wall of the tank 1 through a tank connecting pipe 23 provided on the hollow shaft 8. The lower part of the hollow shaft 8 and the rotating impeller 9 are located inside the tank 1.

[0038] If the angle between the central axes of the aeration device and the horizontal planes is too small, the rotating shaft will be too long, making implementation difficult. If the angle between the central axes of the aeration device and the horizontal planes is 90°, the rotating shaft is the shortest, but it is difficult to install and the effect is poor. Therefore, in this embodiment, the angle between the central axes of the aeration device and the horizontal planes is θ, where θ = 15~90°. 0 In this embodiment, θ is preferably 30°. 0 45 0 60 0 and 75 0 .

[0039] The rotating impeller 9 is powered by an external power unit, and the speed of the motor 6 can range from 0 to 3000 rpm, preferably from 500 to 2000 rpm.

[0040] In this embodiment, the rotating impeller 9 includes a base plate 9-1 and a cover plate 9-2 that are spaced apart vertically and coaxially arranged, a mandrel seat 9-3 formed in the middle of the upper end face of the cover plate 9-2, and a mounting hole extending axially downward from the upper end face of the mandrel seat 9-3 to the lower end face of the base plate 9-1; between the cover plate 9-2 and the base plate 9-1, a gas-liquid mixing chamber 9-4 and a gas-liquid flow channel chamber 9-5 are sequentially divided from the inside to the outside with their axis as the center, and the axial height of the gas-liquid mixing chamber 9-4 is greater than the axial height of the gas-liquid flow channel chamber 9-5; the lower end of the hollow shaft 8 passes through a mounting hole and connects to the rotating impeller 9, located in the... The hollow shaft outlet 8-2 on the lower side wall of the hollow shaft 8 is located inside the gas-liquid mixing chamber 9-4. Multiple liquid inlets 9-6 are provided on the bottom plate 9-1 within the range of the gas-liquid mixing chamber 9-4. The multiple liquid inlets 9-6 are distributed in a circle around the axis. In this embodiment, the shape of the liquid inlet 9-6 is an arc-shaped elongated hole. A gas-liquid outlet 9-7 is formed between the outer edges of the bottom plate 9-1 and the cover plate 9-2. Multiple gas-liquid channels are formed in the gas-liquid flow channel chamber 9-5 by several partitions, which are evenly distributed around the axis. In each gas-liquid flow channel, a diversion and constriction structure and a secondary acceleration and expansion structure are provided from the inside to the outside.

[0041] like Figure 4 As shown, in this embodiment, the partition includes a plurality of first planar partitions 10 and a plurality of second planar partitions 11, all arranged in a circular pattern around an axis and alternately spaced at equal intervals. The length of the first planar partition 10 is greater than the length of the second planar partition 11. The first planar partition 10 penetrates the gas-liquid flow channel chamber 9-5 in the radial direction, and the outer side of the second planar partition 11 extends to the outer edge of the cover plate 9-2 in the radial direction. Two adjacent first planar partitions 10, the bottom plate 9-1, and the cover plate 9-2 form a gas-liquid flow channel, and spaced from the inside to the outside are provided in the gas-liquid flow channel. The flow diversion and constriction structure and the secondary acceleration and expansion structure are described. The flow diversion and constriction structure is a meniscus-shaped block 12 with its concave surface facing outwards. The secondary acceleration and expansion structure consists of two first square bending blocks 13 with their inner folded surfaces facing outwards and two second square bending blocks 14 with their inner folded surfaces facing outwards. The two first square bending blocks 13 and the two second square bending blocks 14 are mirror-symmetrically arranged on both sides of the second planar partition 11. The first square bending blocks 13 are located inside the second square bending blocks 14, and the outermost edge of the second square bending blocks 14 is adjacent to the outer edge of the cover plate 9-2. In other embodiments, the flow diversion and constriction structure can also function in other shapes that are the same or similar.

[0042] When the rotating impeller 9 aerated bioreactor is in operation, the bioreactor stirring device is started, and simultaneously, the rotating impeller 9 aeration motor 6 is started. Fresh air enters from the air inlet 8-1 of the rotating impeller 9 aeration device, then enters the magnetic fluid seal 7 and the hollow shaft 8, and then enters the rotating impeller 9. Driven by the motor 6, the rotating impeller 9 shears and mixes the reaction solution and the incoming gas together inside the rotating impeller 9. Finally, under the action of centrifugal force, the mixture is dispersed into the bioreactor. At this time, the gas is dispersed into microbubbles, which are evenly dispersed into the bioreactor solution under the action of the bioreactor stirring blades. Then, the gas rises to the liquid surface and escapes from the liquid surface, and the waste gas leaves the reactor from the bioreactor outlet 1-1.

[0043] The above-mentioned device is applied to the production of DHA products: A sterile culture medium is prepared in a bioreactor. DHA-producing bacteria are inoculated into the reactor through the inoculation port. Then, sterile air enters from the air inlet 8-1 of the rotating impeller 9 aeration device, passes through the magnetic fluid seal 7 and the hollow shaft 8, and reaches the rotating impeller 9. The rotating impeller 9 shears and mixes the fermentation solution and sterile air to form microbubbles that are dispersed in the fermentation culture medium, providing sufficient dissolved oxygen for the bacteria to multiply and produce DHA. Fermentation conditions: temperature 28℃, ventilation rate 1 vvm, tank pressure 0.06 MPa, dissolved oxygen (DO) 10-20%, sugar replenishment time controlled at residual sugar of 8-10 g / L, fermentation time 140 h. Finally, the wet weight of the bacteria is 416 g / L, the total oil content is 45 g / g, and the DHA content is 35 g / g, representing increases of 20%, 10%, and 10% respectively compared to the original conventional tank. Example 2

[0044] The device used in this embodiment is roughly the same as that in Embodiment 1, except that it uses a different design of rotating impeller 9 for aeration, namely, a shearing and mixing method of arrow-shaped and triangular secondary constriction and expansion tubes.

[0045] Specifically, such as Figure 5As shown, the partition includes multiple first arc-shaped partitions 15 evenly distributed in a circle around an axis. One end of each first arc-shaped partition 15 is located at the outer edge of the cover plate 9-2, and the other end is located on the inner ring of the gas-liquid flow channel chamber 9-5. Two adjacent first arc-shaped partitions 15, the bottom plate 9-1, and the cover plate 9-2 form a gas-liquid flow channel. Within the gas-liquid flow channel, from the inside out, there are sequentially arranged diversion and constriction structures and secondary acceleration and expansion structures. The diversion and constriction structure is an arrow-shaped structural block 16 with its tip pointing inwards. The secondary acceleration and expansion structure is a triangular structural block 17 with its tip pointing towards the arrow-shaped structural block 16. The outer surface of the triangular structural block 17 is located at the outer edge of the cover plate 9-2. Two shearing blocks are mirror-symmetrically arranged on the inner surfaces of two adjacent first arc-shaped partitions 15. The shape of the shearing blocks can be trapezoidal, triangular, hexagonal, or circular. In this embodiment, the shear block is a trapezoidal block. Two trapezoidal blocks 18 are mirror-imagely arranged on the inner sides of two adjacent first arc-shaped partitions 15. The two trapezoidal blocks are located outside the arrow-shaped structural block 16. The tip of the triangular structural block 17 facing the arrow-shaped structural block 16 is located between the two trapezoidal blocks.

[0046] Using the above-described apparatus, a sterile culture medium was prepared in the bioreactor. DHA-producing bacteria were inoculated into the reactor through the inoculation port. Sterile air then entered through the air inlet 8-1 of the rotating impeller 9 aeration device, passed through the magnetic fluid seal 7 and the hollow shaft 8, and reached the rotating impeller 9. The rotating impeller 9 sheared and mixed the fermentation solution and sterile air, forming microbubbles that dispersed in the fermentation medium, providing sufficient dissolved oxygen for bacterial growth and DHA production. Fermentation conditions were: temperature 28℃, aeration rate 1 vvm, tank pressure 0.06 MPa, dissolved oxygen (DO) 10-20%, sugar replenishment time controlled at residual sugar levels of 8-10 g / L, and fermentation time 140 h. Finally, the wet weight of the bacteria was 425 g / L, the total oil content was 47 g / g, and the DHA content was 36 g / g, representing increases of 24%, 13%, and 12% respectively compared to the conventional tank. Example 3

[0047] The device used in this embodiment is roughly the same as that in Embodiment 1, except that it uses a different design of rotating impeller 9 for aeration, namely, a polygonal secondary shrinking tube and expanding tube shearing and mixing method.

[0048] Specifically, such as Figure 6As shown, the partition includes multiple V-shaped partitions 19 evenly distributed in a circle around the axis, with an interior angle greater than 90°. One end of each V-shaped partition 19 is located at the outer edge of the cover plate 9-2, and the other end is located on the inner ring line of the gas-liquid flow channel chamber 9-5. Two adjacent V-shaped partitions 19, the bottom plate 9-1, and the cover plate 9-2 form a gas-liquid flow channel. Within the gas-liquid flow channel, two secondary acceleration and expansion structures are arranged sequentially from the inside to the outside. The two secondary acceleration and expansion structures are two polygonal structural blocks 20 and 21 with different shapes. Both ends of the two polygonal structural blocks are pointed along the extension direction of the gas-liquid flow channel. The inner polygonal structural block 20 and the outer polygonal structural block 21 can be polygonal structures of any shape; different shapes of polygonal structures have different effects.

[0049] Using the above-described apparatus, a sterile culture medium was prepared in the bioreactor. DHA-producing bacteria were inoculated into the reactor through the inoculation port. Sterile air then entered through the air inlet 8-1 of the rotating impeller 9 aeration device, passing through the magnetic fluid seal 7 and the hollow shaft 8 before reaching the rotating impeller 9. The rotating impeller 9 sheared and mixed the fermentation solution and sterile air, forming microbubbles that dispersed in the fermentation medium, providing sufficient dissolved oxygen for bacterial growth and DHA production. Fermentation conditions were: temperature 28℃, aeration rate 1 vvm, tank pressure 0.06 MPa, dissolved oxygen (DO) 10-20%, sugar replenishment time controlled at residual sugar levels of 8-10 g / L, and fermentation time 140 h. Finally, the wet weight of the bacteria was 409 g / L, the total oil content was 44 g / g, and the DHA content was 33 g / g, representing increases of 19%, 9%, and 8% respectively compared to the conventional tank. Example 4

[0050] The device used in this embodiment is roughly the same as that in Embodiment 1, except that it uses a different design of rotating impeller 9 for aeration, namely, a shear mixing method using microchannel flow.

[0051] Specifically, such as Figure 7 As shown, the partition includes multiple second arc-shaped partitions 22 evenly distributed in a circle around the axis. One end of the second arc-shaped partition 22 is located at the outer edge of the cover plate 9-2, and the other end is located on the inner ring line of the gas-liquid flow channel chamber 9-5. Multiple semi-heart-shaped grooves 221 are equally spaced on both sides of the second arc-shaped partition 22 along its arc direction. The semi-heart-shaped grooves 221 on the opposite sides of two adjacent second arc-shaped partitions 22 are arranged opposite each other. Two adjacent second arc-shaped partitions 22, the bottom plate 9-1 and the cover plate 9-2 form a gas-liquid flow channel with a microchannel heart-shaped hybrid shear structure.

[0052] Using the above-described apparatus, a sterile culture medium was prepared in the bioreactor. DHA-producing bacteria were inoculated into the reactor through the inoculation port. Sterile air then entered through the air inlet 8-1 of the rotating impeller 9 aeration device, passing through the magnetic fluid seal 7 and the hollow shaft 8 before reaching the rotating impeller 9. The rotating impeller 9 sheared and mixed the fermentation solution and sterile air, forming microbubbles that dispersed in the fermentation medium, providing sufficient dissolved oxygen for bacterial growth and DHA production. Fermentation conditions were: temperature 28℃, aeration rate 1 vvm, tank pressure 0.06 MPa, dissolved oxygen (DO) 10-20%, sugar replenishment time controlled at residual sugar levels of 8-10 g / L, and fermentation time 140 h. Finally, the wet weight of the bacteria was 418 g / L, the total oil content was 46 g / g, and the DHA content was 37 g / g, representing increases of 22%, 13%, and 14%, respectively, compared to the conventional tank.

[0053] In order to distribute the external liquid more evenly into each flow channel of the rotating impeller 9, so as to improve the gas-liquid mixing and shearing of each fluid, in some embodiments, a liquid guide wheel is provided at the bottom of the gas-liquid mixing chamber 9-4. The liquid guide wheel is fixed to the lower end of the gas guiding structure. The number of guide impellers on the liquid guide wheel is 4, 6, 8, 12, 16 or 24, preferably 6, 8, 12 or 16. Example 5

[0054] The device used in this embodiment is roughly the same as that in embodiment 1, except that it uses a different design of rotating impeller 9 for aeration, namely, a liquid guide wheel 25. The liquid guide wheel 25 is provided at the bottom of the gas-liquid mixing chamber 9-4 and is fixed to the lower end of the air guiding structure.

[0055] Specifically, such as Figure 8As shown, the partition includes multiple first planar partitions 10 and multiple second planar partitions 11, all arranged in a circular pattern around an axis and alternating at equal intervals. The length of the first planar partition 10 is greater than the length of the second planar partition 11. The first planar partition 10 penetrates the gas-liquid flow channel chamber 9-5 in the radial direction, and the outer side of the second planar partition 11 extends to the outer edge of the cover plate 9-2 in the radial direction. Two adjacent first planar partitions 10, the bottom plate 9-1, and the cover plate 9-2 form a gas-liquid flow channel. Within the gas-liquid flow channel, diversion and contraction mechanisms are spaced out from the inside to the outside. The system includes a tubular structure and a secondary acceleration and expansion structure. The diversion and contraction structure is a meniscus-shaped block 12 with its concave surface facing outwards. The secondary acceleration and expansion structure consists of two first square bending blocks 13 with their inner folded surfaces facing outwards and two second square bending blocks 14 with their inner folded surfaces facing outwards. The two first square bending blocks 13 and the two second square bending blocks 14 are mirror-symmetrically arranged on both sides of the second planar partition 11. The first square bending blocks 13 are located inside the second square bending blocks 14, and the outermost edge of the second square bending blocks 14 is adjacent to the outer edge of the cover plate 9-2. In other embodiments, the diversion and contraction structure can also function in other shapes that are the same or similar. Using the above-described apparatus, a sterile culture medium was prepared in the bioreactor. DHA-producing bacteria were inoculated into the reactor through the inoculation port. Sterile air then entered through the air inlet 8-1 of the rotating impeller 9 aeration device, passing through the magnetic fluid seal 7 and the hollow shaft 8 before reaching the rotating impeller 9. The rotating impeller 9 sheared and mixed the fermentation solution and sterile air, forming microbubbles that dispersed in the fermentation medium, providing sufficient dissolved oxygen for bacterial growth and DHA production. Fermentation conditions were: temperature 28℃, aeration rate 1 vvm, tank pressure 0.06 MPa, dissolved oxygen (DO) 10-20%, sugar replenishment time controlled at residual sugar levels of 8-10 g / L, and fermentation time 140 h. Finally, the wet weight of the bacteria was 467 g / L, the total oil content was 46 g / g, and the DHA content was 37 g / g, representing increases of 26%, 20%, and 17% respectively compared to the conventional tank. Example 6

[0056] The device used in this embodiment is roughly the same as that in embodiment 1, except that it uses a different design of rotating impeller 9 for aeration, namely, a liquid guide wheel 25. The liquid guide wheel 25 is provided at the bottom of the gas-liquid mixing chamber 9-4 and is fixed to the lower end of the air guiding structure.

[0057] Specifically, such as Figure 9As shown, the partition includes multiple first arc-shaped partitions 15 evenly distributed in a circle around an axis. One end of each first arc-shaped partition 15 is located at the outer edge of the cover plate 9-2, and the other end is located on the inner ring of the gas-liquid flow channel chamber 9-5. Two adjacent first arc-shaped partitions 15, the bottom plate 9-1, and the cover plate 9-2 form a gas-liquid flow channel. Within the gas-liquid flow channel, from the inside out, there are sequentially arranged flow-diverting and constricting structures and secondary acceleration and expansion structures. The flow-diverting and constricting structure is an arrow-shaped structural block 16 with its tip pointing inwards. The secondary acceleration and expansion structure is a triangular structural block 17 with its tip pointing towards the arrow-shaped structural block 16. The outer surface of the triangular structural block 17 is located at the outer edge of the cover plate 9-2. Two trapezoidal blocks 18 are mirror-image opposite each other on the inner surfaces of two adjacent first arc-shaped partitions 15. The two trapezoidal blocks are located outside the arrow-shaped structural block 16, and the tip of the triangular structural block 17 pointing towards the arrow-shaped structural block 16 is located between the two trapezoidal blocks.

[0058] Using the above-described apparatus, a sterile culture medium was prepared in the bioreactor. DHA-producing bacteria were inoculated into the reactor through the inoculation port. Sterile air then entered through the air inlet 8-1 of the rotating impeller 9 aeration device, passing through the magnetic fluid seal 7 and the hollow shaft 8 before reaching the rotating impeller 9. The rotating impeller 9 sheared and mixed the fermentation solution and sterile air, forming microbubbles that dispersed in the fermentation medium, providing sufficient dissolved oxygen for bacterial growth and DHA production. Fermentation conditions were: temperature 28℃, aeration rate 1 vvm, tank pressure 0.06 MPa, dissolved oxygen (DO) 10-20%, sugar replenishment time controlled at residual sugar levels of 8-10 g / L, and fermentation time 140 h. Finally, the wet weight of the bacteria was 489 g / L, the total oil content was 47 g / g, and the DHA content was 39 g / g, representing increases of 31%, 24%, and 19% respectively compared to the conventional tank. Example 7

[0059] The device used in this embodiment is roughly the same as that in embodiment 1, except that it uses a different design of rotating impeller 9 for aeration, namely, a liquid guide wheel 25. The liquid guide wheel 25 is provided at the bottom of the gas-liquid mixing chamber 9-4 and is fixed to the lower end of the air guiding structure.

[0060] Specifically, such as Figure 10As shown, the partition includes multiple V-shaped partitions 19 that are evenly distributed in a circle around the axis and have an interior angle greater than 90°. One end of the V-shaped partition 19 is located at the outer edge of the cover plate 9-2, and the other end is located on the inner ring line of the gas-liquid flow channel chamber 9-5. Two adjacent V-shaped partitions 19, the bottom plate 9-1, and the cover plate 9-2 form a gas-liquid flow channel. Two secondary acceleration and expansion structures are arranged sequentially from the inside to the outside in the gas-liquid flow channel. The two secondary acceleration and expansion structures are two inner polygonal structural blocks 20 and outer polygonal structural blocks 21 with different shapes. Both ends of the two polygonal structural blocks are pointed along the extension direction of the gas-liquid flow channel.

[0061] Using the above-described apparatus, a sterile culture medium was prepared in the bioreactor. DHA-producing bacteria were inoculated into the reactor through the inoculation port. Sterile air then entered through the air inlet 8-1 of the rotating impeller 9 aeration device, passing through the magnetic fluid seal 7 and the hollow shaft 8 before reaching the rotating impeller 9. The rotating impeller 9 sheared and mixed the fermentation solution and sterile air, forming microbubbles that dispersed in the fermentation medium, providing sufficient dissolved oxygen for bacterial growth and DHA production. Fermentation conditions were: temperature 28℃, aeration rate 1 vvm, tank pressure 0.06 MPa, dissolved oxygen (DO) 10-20%, sugar replenishment time controlled at residual sugar levels of 8-10 g / L, and fermentation time 140 h. Finally, the wet weight of the bacteria was 465 g / L, the total oil content was 45 g / g, and the DHA content was 37 g / g, representing increases of 25%, 19%, and 16% respectively compared to the conventional tank. Example 8

[0062] The device used in this embodiment is roughly the same as that in embodiment 1, except that it uses a different design of rotating impeller 9 for aeration, namely, a liquid guide wheel 25. The liquid guide wheel 25 is provided at the bottom of the gas-liquid mixing chamber 9-4 and is fixed to the lower end of the air guiding structure.

[0063] Specifically, such as Figure 11 As shown, the partition includes multiple second arc-shaped partitions 22 evenly distributed in a circle around the axis. One end of the second arc-shaped partition 22 is located at the outer edge of the cover plate 9-2, and the other end is located on the inner ring line of the gas-liquid flow channel chamber 9-5. Multiple semi-heart-shaped grooves 221 are equally spaced on both sides of the second arc-shaped partition 22 along its arc direction. The semi-heart-shaped grooves 221 on the opposite sides of two adjacent second arc-shaped partitions 22 are arranged opposite each other. Two adjacent second arc-shaped partitions 22, the bottom plate 9-1 and the cover plate 9-2 form a gas-liquid flow channel with a microchannel heart-shaped hybrid shear structure.

[0064] Using the above-described apparatus, a sterile culture medium was prepared in the bioreactor. DHA-producing bacteria were inoculated into the reactor through the inoculation port. Sterile air then entered through the air inlet 8-1 of the rotating impeller 9 aeration device, passing through the magnetic fluid seal 7 and the hollow shaft 8 before reaching the rotating impeller 9. The rotating impeller 9 sheared and mixed the fermentation solution and sterile air, forming microbubbles that dispersed in the fermentation medium, providing sufficient dissolved oxygen for bacterial growth and DHA production. Fermentation conditions were: temperature 28℃, aeration rate 1 vvm, tank pressure 0.06 MPa, dissolved oxygen (DO) 10-20%, sugar replenishment time controlled at residual sugar levels of 8-10 g / L, and fermentation time 140 h. Finally, the wet weight of the bacteria was 481 g / L, the total oil content was 45 g / g, and the DHA content was 37 g / g, representing increases of 29%, 20%, and 18% respectively compared to the conventional tank.

[0065] Those skilled in the art should understand that the above description is merely a specific embodiment of the present invention and is not intended to limit the present invention. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of the present invention should be included within the protection scope of the present invention.

Claims

1. A rotating impeller, characterized in that, The system includes a base plate and a cover plate that are spaced apart and coaxially arranged, a mandrel seat formed in the middle of the upper surface of the cover plate, and mounting holes extending axially downward from the upper surface of the mandrel seat to the lower surface of the base plate. Between the cover plate and the base plate, the system is divided into a gas-liquid mixing chamber and a gas-liquid flow channel chamber, centered on their axis. A gas guiding structure extends into the gas-liquid mixing chamber. Multiple liquid inlets are provided on the base plate within the gas-liquid mixing chamber. A gas-liquid outlet is formed between the outer edges of the base plate and the cover plate. Multiple gas-liquid outlets are formed within the gas-liquid flow channel chamber by several partitions. The gas-liquid flow channels are evenly distributed around the axis. Each gas-liquid flow channel is provided with one or more of the following: a flow splitting and constriction structure, a secondary acceleration and expansion structure, and a microchannel mixing and shearing structure. A liquid guide wheel is provided at the bottom of the gas-liquid mixing chamber. The liquid guide wheel is fixed to the lower end of the gas guiding structure. The number of guide impellers on the liquid guide wheel is 4, 6, 8, 12, 16, or 24. The gas guiding structure is connected to the rotating impeller through the mounting hole. The axial height of the gas-liquid mixing chamber is greater than the axial height of the gas-liquid flow channel chamber.

2. The rotating impeller according to claim 1, characterized in that, The partition includes multiple first planar partitions and multiple second planar partitions, all arranged in a circular pattern around an axis and alternately spaced at equal intervals. The length of the first planar partition is greater than the length of the second planar partition. The first planar partition penetrates the gas-liquid flow channel chamber in the radial direction, and the outer side of the second planar partition extends to the outer edge of the cover plate in the radial direction. Two adjacent first planar partitions, the bottom plate, and the cover plate form a gas-liquid flow channel. In the gas-liquid flow channel, a diversion and constriction structure and a secondary acceleration and expansion structure are provided from the inside to the outside. The diversion and constriction structure is a crescent-shaped structural block with the concave surface facing outward. The secondary acceleration and expansion structure consists of two first square bending blocks with the inner folding surface facing outward and two second square bending blocks with the inner folding surface facing outward. The two first square bending blocks and the two second square bending blocks are mirror-symmetrically arranged on both sides of the second planar partition, with the first square bending blocks located inside the second square bending blocks.

3. The rotating impeller according to claim 2, characterized in that, The partition includes multiple first arc-shaped partitions evenly distributed in a circle around an axis. One end of each first arc-shaped partition is located at the outer edge of the cover plate, and the other end is located on the inner ring line of the gas-liquid flow channel chamber. Two adjacent first arc-shaped partitions, the bottom plate, and the cover plate form a gas-liquid flow channel. Within the gas-liquid flow channel, a diversion and constriction structure and a secondary acceleration and expansion structure are arranged sequentially from the inside to the outside. The diversion and constriction structure is an arrow-shaped structural block with its tip pointing inward. The secondary acceleration and expansion structure is a triangular structural block with its tip pointing towards the arrow-shaped structural block. The outer side of the triangular structural block is located at the outer edge of the cover plate. Two shearing trapezoidal blocks are mirror-symmetrically arranged on the inner sides of two adjacent first arc-shaped partitions.

4. The rotating impeller according to claim 1, characterized in that, The partition includes multiple V-shaped partitions that are evenly distributed in a circle around the axis and have an interior angle greater than 90°. One end of each V-shaped partition is located at the outer edge of the cover plate, and the other end is located on the inner ring line of the gas-liquid flow channel chamber. Two adjacent V-shaped partitions, the bottom plate, and the cover plate form a gas-liquid flow channel. Two secondary acceleration and expansion structures are arranged sequentially from the inside to the outside of the gas-liquid flow channel. The two secondary acceleration and expansion structures are two polygonal structural blocks of different shapes, and both ends of the two polygonal structural blocks along the extension direction of the gas-liquid flow channel are pointed.

5. The rotating impeller according to claim 1, characterized in that, The partition includes multiple second arc-shaped partitions evenly distributed in a circle around the axis. One end of the second arc-shaped partition is located at the outer edge of the cover plate, and the other end is located on the inner ring line of the gas-liquid flow channel chamber. Multiple semi-heart-shaped grooves are equally spaced on both sides of the second arc-shaped partition along its arc direction. The semi-heart-shaped grooves on the opposite sides of two adjacent second arc-shaped partitions are arranged opposite each other. Two adjacent second arc-shaped partitions, the bottom plate, and the cover plate form a gas-liquid flow channel with a microchannel heart-shaped hybrid shear structure.

6. An aeration device, characterized in that, The aeration device includes a motor, a magnetic fluid seal, a hollow shaft, and a rotating impeller. An air inlet is provided on the upper side wall of the hollow shaft. The upper end of the hollow shaft is connected to an external air source through the magnetic fluid seal. The motor is connected to the hollow shaft through a coupling frame. The rotating impeller is the rotating impeller as described in any one of claims 1 to 5. The lower end of the hollow shaft is fixed to the rotating impeller. An air outlet located on the lower side wall of the hollow shaft is located in the gas-liquid mixing chamber.

7. A rotating impeller aerated bioreactor, characterized in that, The device includes a tank, a stirring device, and the aeration device as described in claim 6. The tank has an air outlet and a material outlet. The stirring device is fixed to the tank. The aeration device is obliquely fixed to the lower side wall of the tank via a tank connecting pipe mounted on the hollow shaft. The lower part of the hollow shaft and the rotating impeller are located inside the tank. The angle between the central axis of the aeration device and the horizontal plane is θ, where θ = 15~90°. 0 .

8. The rotary impeller aerated bioreactor according to claim 7, characterized in that, The angle θ between the central axis of the aeration device and the horizontal plane is 30°. 0 45 0 60 0 and 75 0 .

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