Low-power bioreactor

Abstract

In conventional bioreactors consisting of an agitator and an aeration device, there was a problem that, depending on the diameter of the aerated bubbles, the flow within the vessel was obstructed, adversely affecting the flow action created by the agitator blades. [Solution] The low-power bioreactor of the present invention comprises a tank for holding a liquid, rotors provided in the tank for discharging the liquid radially outward, stator blades consisting of a plurality of radially extending strips fixed to the center of the bottom of the tank below the rotors, and aeration means, wherein the aeration means is a means for aerating air bubbles into an upward flow formed in the center of the tank by the rotors and stator blades.

Description

[Technical Field]

[0001] The present invention relates to a low-power bioreactor, particularly a bioreactor (biochemical reaction device) comprising an agitator and an aeration device, for culturing, for example, cultures of microbial, animal or plant cells or bacterial cells in a medium such as a culture solution. [Background technology]

[0002] Conventionally, in bioreactors with a high aeration system that requires a high OTR (Oxygen Transfer Rate), such as for microbial cultivation, it has been common to aerate a large amount of gas (air) into the culture tank and forcibly disperse the air using turbine blades.

[0003] Therefore, the stirring power required to disperse the gas is 2 to 3 kW / m, with a Pv value of energy consumption per unit volume. 3 Furthermore, the power consumption of the blower for large-volume aeration is also high, and as the culture volume increases through scale-up, there has been a demand for reducing these power consumptions.

[0004] To address this issue, turbine blades with high gas dispersion efficiency and liquid fluidity have been developed, but in recent years, as larger turbines are desired, further improvements in efficiency and power saving have become essential.

[0005] To achieve this, we have developed and commercialized a low-power bioreactor that combines a low-power stirring system (RB mixing system) with an aeration device that generates fine bubbles (Patent Document 1).

[0006] This low-power bioreactor uses a rotating blade at the top of the tank and a stationary blade fixed to the bottom, allowing the liquid to circulate within the tank with low power consumption.Fine bubbles generated by a bubble generator installed in a circulation pipe connected to the outer surface of the tank are introduced into the liquid circulating within the tank, thereby increasing the gas dispersion efficiency with low power consumption. [Prior art documents] [Patent documents]

[0007] [Patent Document 1] JP 2024-74193 A Summary of the Invention [Problem to be solved by the invention]

[0008] However, in this low-power bioreactor, the flow action to circulate fine bubbles within the culture tank is important, and there was a problem that depending on the bubble diameter, the flow within the tank could be obstructed, adversely affecting the flow action created by the stirring blades.

[0009] As a result of various investigations, the present invention has solved the above problems by introducing fine bubbles in accordance with the upward flow formed by the rotor and stator blades. [Means for solving the problem]

[0010] The low-power bioreactor of the present invention comprises a tank for containing a liquid, a rotor provided in the tank for discharging the liquid radially outward, a stator consisting of a plurality of radially extending strips fixed to the center of the bottom of the tank below the rotor, and an aeration means, the aeration means being configured by the rotor and the stator. A swirling flow portion that swirls downward along the inner circumferential surface of the tank is formed. Formed in the center of the tank Among the rising currents A means for ventilating bubbles into the upward flow. The bubble discharge portion of the ventilation means is provided in the upward flow below the rotor blades, above a gap formed in the center of the bottom portion corresponding to the intersection of the plurality of stator blades. It is characterized by the following.

[0012] Also, The low-power bioreactor of the present invention comprises a tank for containing a liquid, rotors provided in the tank for discharging the liquid radially outward, stator blades consisting of a plurality of radially extending band-shaped plates fixed to the center of the bottom of the tank below the rotors, aeration means, and a cylindrical body with open upper and lower ends provided in the center of the tank, the cylinder being shaped so that a swirling flow portion formed by the rotors and stator blades swirling downward along the inner circumferential surface of the tank passes to the outside and an ascending flow formed in the center passes to the inside, the aeration means being a means for passing air bubbles into the ascending flow, and the bubble discharge portion of the aeration means being provided in the cylinder. It is characterized by:

[0015] Also, The low-power bioreactor of the present invention comprises a tank for containing a liquid, a rotor provided in the tank for discharging the liquid radially outward, a stator blade consisting of a plurality of radially extending band-shaped plates fixed to the center of the bottom of the tank below the rotor, an aeration means, and a cylindrical body with open upper and lower ends provided in the center of the tank, the body being shaped so that a swirling flow portion that swirls downward along the inner circumferential surface of the tank, formed by the rotor and the stator blade, passes outward, and an ascending flow formed in the center passes inward, the aeration means being a means for aerating bubbles into the ascending flow, and the bubble discharge portion of the aeration means is provided on the inner circumferential surface of the cylinder. It is characterized by: [Effects of the Invention]

[0016] According to the present invention, the liquid can be circulated in the stirring tank with low power.

[0017] Furthermore, the bubbles from the ventilation means are released into the tornado-like upward flow generated in the center of the tank and rise along with the upward flow, so they do not obstruct the flow within the tank. In addition, the air lift action of the bubbles has the effect of accelerating the upward flow, and fine bubbles are carried by the fluid and dispersed within the tank, thereby improving gas absorption performance. [Brief explanation of the drawings]

[0018] [Figure 1] FIG. 1 is an explanatory longitudinal sectional side view of a low-power bioreactor of the present invention. [Figure 2] FIG. 1 is an illustrative cross-sectional plan view of a low-power bioreactor of the present invention. [Figure 3] FIG. 1 is an explanatory longitudinal sectional side view of a low-power bioreactor of the present invention. [Figure 4] FIG. 1 is an explanatory vertical cross-sectional side view of another embodiment of the low-power bioreactor of the present invention. [Figure 5] FIG. 1 is an explanatory vertical cross-sectional side view of another embodiment of the low-power bioreactor of the present invention. DETAILED DESCRIPTION OF THE INVENTION

[0019] Hereinafter, an embodiment of the present invention will be described with reference to the drawings. [Example]

[0020] The low-power bioreactor of the present invention comprises, for example, a cylindrical stirring tank 1 with a bottom that can hold a liquid, a rotating shaft 2 that is suspended within the stirring tank 1, stirring blades 3 that are attached to the rotating shaft 2 and that discharge the liquid radially outward, stationary blades 4 that are attached to the bottom 1a of the stirring tank 1 below the stirring blades 3 and that generate an upward flow, and a ventilation means.

[0021] The stirring blades 3 are, for example, composed of blade plates 3a such as four rectangular flat paddle blades fixed radially to the lower end of the rotating shaft 2 provided in the center of the stirring tank 1, and are provided in the upper part of the stirring tank 1, such as near the liquid surface in the liquid.

[0022] As shown in FIG. 2, the stator blades 4 are made up of a plurality of identically shaped linear band-shaped plates 4a provided in the center of the bottom 1a of the stirring vessel 1, and the band-shaped plates 4a are fixed in parallel and radial directions at a distance d from a radial line R passing through the center of the bottom 1a of the stirring vessel 1 below the stirring impellers 3, for example, four in number, and a gap is formed in the center of the bottom corresponding to the intersection of these band-shaped plates 4a.

[0023] The agitator blades 3 and the stationary blades 4 allow the liquid in the agitator tank 1 to circulate with low power through a downward swirling flow along the inner surface 1b of the agitator tank 1 and a tornado-like upward flow generated in the center.

[0024] The ventilation means is a means for ventilating bubbles into the tornado-shaped upward flow portion, rather than the swirling flow portion formed by the stirring blades 3 and the stationary blades 4, and for example, as shown in Figures 1 to 3, the bubble discharge section 5 of the ventilation means is provided within the tornado-shaped upward flow portion.

[0025] For example, the bubble discharge portion 5 is provided above a gap formed in the center of the bottom portion 1 a corresponding to the intersection of the band-shaped plates 4 a of the stator blades 4 .

[0026] Moreover, it is preferable that the bubble discharge portion 5 is provided at the same height as the stator blades 4 or at a position slightly above that, where an upward flow is generated and at a lower position.

[0027] The ventilation means may also be configured to emit fine bubbles, for example, UFB (ultra fine bubbles) that are bubbles with a diameter of less than 1 micrometer (μm).

[0028] The bubbles to be released are not limited to UFB.

[0029] Since the present invention is configured as described above, when the agitator blades 3 installed near the liquid surface are rotated, as shown in Figure 3, the liquid from the agitator blades 3 is discharged radially outward and hits the inner surface 1b of the agitator vessel 1, generating a downward swirling flow along the inner surface of the agitator vessel 1. The liquid then reaches the bottom 1a and moves to the center of the bottom 1a, where it is urged by the stator blades 4 of the bottom 1a to generate a tornado-like upward flow in the center. The rising liquid is then discharged radially outward by the agitator blades 3, and the liquid circulates within the agitator vessel 1 with low power.

[0030] Furthermore, the bubbles from the bubble discharge section 5 of the aeration means are discharged into the tornado-like upward current generated in the center of the tank and rise along with the upward current, so they do not obstruct the flow within the tank. Furthermore, the air lift action of the bubbles accelerates the upward current, so that fine bubbles can be carried by the fluid and dispersed within the tank without requiring aeration power, thereby improving gas absorption performance.

[0031] Therefore, the air is ventilated directly into the upward flow. tank This does not impede the circulation flow within the reactor, and also provides more efficient fluid flow and gas dispersion, enabling cultivation with low power consumption. [Example]

[0032] In Example 1, the bubble discharge section 5 of the ventilation means was provided within the rising flow portion as a means for ventilating bubbles into the tornado-shaped rising flow portion formed by the agitating blades 3 and the stator blades 4. In Example 2, a separation device is provided to separate the swirling flow formed by the rotor blades 3 and the stator blades 4, which swirls along the inner surface of the agitating tank 1, from the rising flow rising in the center, and the ventilation means is provided within this separation device.

[0033] The separation device is, for example, as shown in FIG. 4, a cylindrical body 6 with open top and bottom ends, which is provided in the center of the stirring tank 1 at a desired distance from the inner circumferential surface 1b, and a ventilation means is provided inside the body 6 to ventilate the bubbles.

[0034] The cylindrical body 6 is provided in the tank 1 and is formed in such a shape that the swirling flow portion, which swirls along the inner peripheral surface of the stirring tank 1 formed by the stirring blades 3 and the stationary blades 4, passes outside the cylindrical body 6 and the ascending flow portion passes inside.

[0035] For example, the cylindrical body 6 is not particularly limited as long as it has a shape that can separate the swirling flow portion and the ascending flow portion, but for example, the inner diameter of the cylindrical body 6 is smaller than the outer diameter of the stator vane 4 and larger than the gap formed in the center of the bottom 1 a of the stator vane 4.

[0036] The lower end of the cylindrical body 6 is higher than the height of the stationary blades, and the upper end is lower than the height of the rotor blades.

[0037] Inside the cylindrical body 6, a bubble release section (not shown) is provided as a ventilation means.

[0038] It is also possible to provide a bubble discharge portion on the inner peripheral surface of the cylindrical body 6, and allow ventilation to the inside from the bubble discharge portion.

[0039] In this embodiment, aeration is not performed to the swirling flow swirling around the inner surface of the stirring tank 1, but only to the upward flow. As a result, similar to the first embodiment, more efficient flow action and gas dispersion action are achieved, and cultivation with low power consumption is realized. [Explanation of symbols]

[0040] 1 Mixing tank 1a bottom 1b Inner surface 2 rotation axes 3 Mixing blades 3a wing plate 4 Stator blades 4a Strip 5. Bubble release section 6 cylinder

Claims

1. a tank for containing a liquid; a rotor disposed within the tank and configured to discharge the liquid radially outward; a stationary vane consisting of a plurality of strip-shaped plates extending radially and fixed to a central portion of the bottom of the tank below the rotor; It comprises a ventilation means, the aeration means is a means for aerating air bubbles into a swirling flow portion formed by the rotor and the stator vanes and swirling downward along the inner circumferential surface of the tank and into an ascending flow formed in the center of the tank, a low-power bioreactor characterized in that the bubble discharge section of the aeration means is provided in the upward flow, below the rotor, above a gap formed in the center of the bottom corresponding to the intersection of the plurality of stator vanes.

2. A tank for holding a liquid; a rotor disposed within the tank and configured to discharge the liquid radially outward; a stationary vane consisting of a plurality of strip-shaped plates extending radially and fixed to a central portion of the bottom of the tank below the rotor; Ventilation means; The tank is provided in the center thereof with a cylindrical body having upper and lower open ends, the cylindrical body is formed in a shape that allows a swirling flow portion formed by the rotor blades and the stator blades and swirling downward along the inner circumferential surface of the tank to pass through on the outside, and allows an upward flow formed in a central portion to pass through on the inside, the aeration means is a means for aerating air bubbles into the upward flow, A low-power bioreactor characterized in that the bubble discharge portion of the aeration means is provided inside the cylindrical body.

3. A tank for holding a liquid; a rotor disposed within the tank and configured to discharge the liquid radially outward; a stationary vane consisting of a plurality of strip-shaped plates extending radially and fixed to a central portion of the bottom of the tank below the rotor; Ventilation means; The tank is provided in the center thereof with a cylindrical body having upper and lower open ends, the cylindrical body is formed in a shape that allows a swirling flow portion formed by the rotor blades and the stator blades and swirling downward along the inner circumferential surface of the tank to pass through on the outside, and allows an upward flow formed in a central portion to pass through on the inside, the aeration means is a means for aerating air bubbles into the upward flow, A low-power bioreactor characterized in that the bubble release portion of the aeration means is provided on the inner peripheral surface of the cylindrical body.

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