Spiral stirring type bioreactor for microbial culture and carbon sequestration

Abstract

The utility model belongs to the crossing field of bioengineering and environmental protection, and particularly discloses a spiral stirring type bioreactor for microorganism culture and carbon sequestration. The spiral stirring type bioreactor comprises a shell, a multi-stage stirring system, a precise temperature control system and a gas-liquid distribution system. Through the innovative structural design, the comprehensive efficiency of the bioreactor is remarkably improved; a unique multi-stage stirring system effectively eliminates a mixing dead angle, so that efficient mass transfer and uniform distribution of a culture solution are realized; meanwhile, a temperature control system is combined, so that the requirement of high-precision constant-temperature culture is met, and a stable microorganism growth environment is maintained with low energy consumption; the gas-liquid distribution system obviously improves the gas utilization rate, and is beneficial to improving the carbon sequestration level. Therefore, the problems of low mixing efficiency, poor temperature control level, low CO2 utilization rate and the like of the traditional bioreactor are effectively solved.

Description

TECHNICAL FIELD

[0001] The utility model belongs to the cross field of bioengineering and environmental protection, and specifically relates to a spiral stirring type bioreactor for microbial culture and carbon fixation. BACKGROUND

[0002] Microbial culture of biological carbon fixation refers to the process of converting carbon dioxide (CO2) into organic matter by microorganisms (such as bacteria, algae, etc.). This process is of great significance in microbial metabolism, not only helping to reduce the CO2 content in the gas, but also producing valuable biological products.

[0003] In the field of microbial culture and biological carbon fixation, the existing technical system still has significant technical bottlenecks. First, the traditional stirring type bioreactor mostly uses single-layer paddle or magnetic stirring structure, and its fluid dynamics characteristics result in low mixing efficiency, especially forming obvious mixing dead angles at the edge and bottom of the reactor. This uneven mass transfer makes the oxygen transfer coefficient (kLa) generally lower than 15h -1 , directly limiting the cell density and biomass accumulation rate. Second, the temperature control system design mainly relies on electric heating rods or external jacket temperature control, and the thermal conduction hysteresis results in a temperature fluctuation range of ±2℃, which is difficult to meet the demand for high-precision constant temperature culture within ±0.5℃ for thermophilic bacteria (such as Thermus thermophilus) or psychrophilic bacteria (such as Psychrobacter), and the high energy consumption problem is prominent. Third, the gas distribution technology mostly adopts a single-point straight injection gas inlet mode at the top, and the dispersion of gas in the liquid phase is insufficient, resulting in limited contact area between CO2 molecules and microorganisms, with an actual utilization rate of only 30-40%, and the residual CO2 concentration in the exhaust gas exceeds 20%, which not only increases the carbon source loss but also intensifies the local pH fluctuation.

[0004] These systematic defects not only restrict the large-scale application of industrial biological carbon fixation, but also hinder the technical breakthrough of synthetic biology in the field of carbon capture, and it is urgent to realize the technological leap through multi-scale engineering optimization. UTILITY MODEL CONTENTS

[0005] To solve the above problems, the utility model provides a spiral stirring type bioreactor for microbial culture and carbon fixation, which is a bioreactor system integrated with spiral stirring, precise temperature control and uniform gas distribution, used for high-density expansion and carbon dioxide fixation of chemoautotrophic microorganisms, suitable for industrial waste gas treatment, biological energy production and microbial manufacturing field, and can effectively solve the above technical problems existing in the traditional stirring type bioreactor.

[0006] To achieve the above purpose, the utility model adopts the following specific technical solutions:

[0007] A spiral stirring bioreactor for microbial culture and carbon sequestration comprises:

[0008] A shell is a hollow cylindrical structure with a cover;

[0009] A multi-stage stirring system comprises a rotating shaft vertically arranged in the shell, and a plurality of propellers arranged axially and spaced apart on the rotating shaft;

[0010] A precision temperature control system comprises a spiral stainless steel coil pipe arranged in the shell, and a black polyurethane sponge layer and a vacuum aluminum film reflection layer wrapped in the peripheral wall of the shell in sequence, and the stainless steel coil pipe is connected to an external water bath device;

[0011] A gas-liquid distribution system comprises a gas distribution assembly and a liquid distribution assembly; the gas distribution assembly comprises a gas mixing chamber connected to a CO2 cylinder arranged at the top of the shell, and a microporous ceramic diffuser arranged below the gas mixing chamber; the liquid distribution assembly comprises a flow guide conical cover arranged at the culture medium inlet of the peripheral wall of the shell, and the flow guide conical cover is connected to a liquid storage tank through a pipeline.

[0012] Preferably, the propeller is provided with three propellers, each propeller has three blades, and the blades are arranged at an interval of 120° along the circumference of the rotating shaft, and the blade angle (the angle between the propeller chord and the propeller rotation plane) is 15-45°; the axial distance between adjacent propellers is 5cm.

[0013] Preferably, the top of the rotating shaft is connected to a servo motor, and the rotating shaft is driven to rotate by the servo motor.

[0014] Preferably, the gas mixing chamber is connected to the CO2 cylinder through a pipeline provided with a mass flow controller, and the mass flow controller is also connected to an industrial waste gas pipeline.

[0015] Preferably, the gas distribution assembly further comprises an exhaust port arranged below the gas mixing chamber of the shell.

[0016] Preferably, the liquid distribution assembly further comprises liquid discharge ports arranged at intervals along the height direction of the shell.

[0017] Further, the liquid discharge ports are provided with three liquid discharge ports arranged at intervals of 5cm along the height direction of the shell; and the liquid discharge ports are communicated with the shell through pipelines provided with solenoid valves.

[0018] Preferably, a peristaltic pump is arranged on the connecting pipeline between the flow guide conical cover and the liquid storage tank.

[0019] The utility model has the following beneficial effects:

[0020] The utility model discloses a comprehensive performance of biological reactor is improved obviously through the innovative structure design: the unique multistage stirring system effectively eliminates the mixed dead angle, realizes the efficient mass transfer and uniform distribution of culture solution, improves the mixing efficiency, and the low energy consumption is maintained with the stable microbial growth environment, and the gas utilization rate is improved obviously, and it is helpful to improve the carbon fixation level. BRIEF DESCRIPTION OF DRAWINGS

[0021] Figure 1 Structure diagram of the spiral stirring type biological reactor for microbial culture and carbon fixation of example 1.

[0022] In the drawing: 1 - shell, 2 - servo motor, 3 - rotating shaft, 4 - propeller, 5 - black polyurethane sponge layer, 6 - vacuum aluminized film reflection layer, 7 - stainless steel coil pipe, 8 - water bath device, 9 - gas mixing cavity, 10 - microporous ceramic diffuser, 11 - mass flow controller, 12 - CO2 gas cylinder, 13 - exhaust port, 14 - electromagnetic valve, 15 - liquid discharge port, 16 - flow guide cone cover, 17 - peristaltic pump, 18 - liquid storage tank, 19 - gas (black represents carbon dioxide, white represents industrial waste gas), 20 - microorganism. DETAILED DESCRIPTION

[0023] The utility model is further explained in connection with the drawings and specific embodiment.

[0024] Example 1

[0025] The embodiment provides a spiral stirring type biological reactor for microbial culture and carbon fixation, and the structure is as shown in Figure 1 It includes shell 1, multistage stirring system, precision temperature control system and gas-liquid distribution system, and is as follows:

[0026] I. Reactor main body

[0027] The reactor main body (i.e. shell 1) adopts organic glass (PMMA) cylindrical design, and the diameter is 10cm*height 30cm, and the effective volume is 2L, the inside is hollow and has an upper cover.PMMA material has chemical corrosion resistance (resistant to pH 3-10) and low biological adhesion characteristics.Cylindrical configuration combines high aspect ratio (3:1) design, which optimizes the fluid mechanics distribution and reduces vortex energy loss.The scale line (accuracy ±1mm) is arranged on the outer wall of shell 1, which is used for accurately monitoring the liquid level change.

[0028] II. Multistage stirring system

[0029] The multi-stage stirring system comprises a rotating shaft 3 vertically arranged inside the shell 1, three propellers 4 arranged at intervals along the axis of the rotating shaft 3, and a servo motor 2 connected to the top of the rotating shaft 3 to drive the rotating shaft 3 to rotate and in turn drive the propellers 4 to rotate. Each propeller 4 has three blades arranged at an interval of 120° along the circumference of the rotating shaft 3, with a blade inclination angle of 15-45° (the propeller 4 preferably has an adjustable blade inclination angle, and the blade inclination angle is preferably 30°), and the blade is an S-shaped blade with a curvature radius of 8 mm; the axial distance between adjacent propellers 4 is 5 cm.

[0030] Fluid dynamics optimization: the three-blade cooperation forms an axial-radial composite flow field, effectively improving mixing uniformity, shortening mixing time, and improving mixing efficiency. For example, at a rotating speed of 120 rpm, computational fluid dynamics (CFD) simulation shows that the shear stress uniformity index (SSUI) of the propeller 4 of the utility model reaches 0.89 (0.62 for a traditional single-blade), and the mixing time is shortened to 45 seconds (120 seconds for a traditional reactor).

[0031] Dead angle prevention design: the distance between the propellers 4 and the blade inclination angle are matched, so that the culture solution forms a continuous vortex ring structure, the thickness of the liquid phase mass transfer boundary layer is reduced to 0.12 mm (0.35 mm for a traditional stirrer), and the oxygen mass transfer coefficient (kLa) is increased to 25 h-1.

[0032] Three, precise temperature control system

[0033] The precise temperature control system comprises a spiral 316L stainless steel coil pipe 7 built-in the shell 1 and a black polyurethane sponge layer 5 and a vacuum aluminum film reflection layer 6 wrapped in the outer peripheral wall of the shell 1 in sequence, and the stainless steel coil pipe 7 is connected to an external water bath device 8.

[0034] Thermal insulation layer design: the reactor is wrapped with a 2cm-thick black polyurethane sponge layer 5 (thermal conductivity 0.023 W / m·K) and a vacuum aluminum film reflection layer 6 (thermal reflectivity ≥95%), which reduces the interference of environmental temperature. The black polyurethane sponge layer 5 has good thermal insulation performance, can effectively reduce the transfer of heat, and keep the temperature inside the container stable, and the vacuum aluminum film reflection layer 6 can block heat, oxygen and moisture, and prevent the influence of the external environment on the inside of the container.

[0035] Water circulation temperature control: the built-in spiral 316L stainless steel coil pipe 7 (inner diameter 3mm) is connected to the external high-precision water bath device 8 (temperature control range 5-75℃, precision ±0.1℃).

[0036] The precision temperature control system of the embodiment improves the temperature control precision and reduces energy loss by the rapid heat conduction temperature control of the built-in stainless steel coil 7, combined with the temperature stability of the black polyurethane sponge layer 5 and the vacuum aluminum film reflection layer 6 wrapped outside the shell. Specifically, the precision temperature control system realizes that the temperature fluctuation of the culture solution in the reactor is ≤±0.3℃ (when the circulating water flow is 0.1-5 L / m), and the system energy consumption is ≤50 W, which is 30% lower than the traditional electric heating and has no risk of local overheating.

[0037] IV. Gas-liquid distribution system

[0038] The gas-liquid distribution system includes a gas distribution assembly and a liquid distribution assembly. The gas distribution assembly includes a gas mixing chamber 9 arranged at the top of the shell 1, a microporous ceramic diffuser 10 arranged below the gas mixing chamber 9, and an exhaust pipe 13 arranged below the gas mixing chamber 9 in the shell 1. The gas mixing chamber 9 is connected to a CO2 cylinder 12 through a pipeline installed with a mass flow controller 11, and the mass flow controller 11 is also connected to an industrial waste gas pipeline. The liquid distribution assembly includes a flow guide conical cover 16 arranged at the culture medium inlet at the bottom of the peripheral wall of the shell 1 and liquid discharge ports 15 arranged along the height direction of the shell 1 at intervals. The flow guide conical cover 16 is connected to a liquid storage tank 18 through a pipeline installed with a peristaltic pump 17. The liquid discharge ports 15 are provided with three, arranged at intervals of 5 cm along the height direction of the shell 1; and the liquid discharge ports 15 are communicated with the shell 1 through a pipeline installed with a solenoid valve 14.

[0039] Gas input: The top is equipped with a gas mixing chamber 9 (volume 50 mL), through which CO2 cylinders 12 and CO2-containing industrial waste gas are connected to the mass flow controller 11, and the mixed gas is uniformly input through the microporous ceramic diffuser 10 (pore size 10 μm).

[0040] Liquid phase distribution: The bottom is provided with a culture medium inlet, which is injected by a peristaltic pump 17, and a flow guide conical cover 16 is arranged at the inlet to avoid liquid flow impact damage to the bacterial cells.

[0041] Multi-stage liquid discharge design: A liquid discharge port 15 with a pore size of 3 mm is arranged every 5 cm along the height of the reactor, and three liquid discharge ports 15 can be used for sampling at different positions to detect carbon fixation indicators, microbial indicators, etc. The sampling time can be at each stage before, during and after the reaction, and the culture solution is discharged through the solenoid valve 14 for time control.

[0042] The above gas-liquid distribution system design can effectively improve the dispersion of gas in the liquid phase, combined with the above multi-stage stirring system and precision temperature control system, to realize sufficient carbon fixation of microorganisms and greatly improve the CO2 utilization rate. Data shows that the reactor of the embodiment can improve the CO2 utilization rate to 68% (traditional single-point gas inlet is only 30-40%), and the residual CO2 concentration of waste gas is reduced to 6.5%.

[0043] The following is a specific application example of using the bioreactor of the present embodiment for microbial culture and carbon sequestration, which is only used to illustrate the method of using the reactor of the present embodiment, and is not a limitation on the process parameters.

[0044] S1. Inoculation and loading: Thiobacillus denitrificans was pre-cultured in a shaker (30℃, 150rpm) to OD 600 =1.2±0.1; the bacterial solution was mixed with the culture medium at a volume ratio of 1:1, and the mixture was poured into the reactor from the flow cone cover 16 by a peristaltic pump 17, with a total addition amount of 1L;

[0045] S2. Gas input: CO2 and industrial waste gas were mixed in the gas mixing chamber 9 of the reactor by mass flow controllers 11 (CO2 final concentration 50%), and the gas flow rate was adjusted according to the gas-liquid ratio of 1:0.5, and the mixed gas was uniformly input through the microporous ceramic diffuser 10;

[0046] S3. Dynamic culture: start the propeller 4, control the rotating speed at 120rpm; water was supplied to the stainless steel coil 7 from the water bath device 8, and the water temperature was controlled at 28℃±0.3℃; during the culture process, electron donors NaNO2, Na2S and Na2S2O3 were added; the culture process was completed after 96h.

[0047] The present embodiment is only an explanation of the present utility model, and is not a limitation on the present utility model, any changes made by those skilled in the art after reading the specification of the present utility model will be protected by the patent law as long as it is within the scope of the claims of the present utility model.

Claims

1. A spiral agitated bioreactor for microbial cultivation and carbon sequestration, characterized in that, include: The shell (1) is a cylindrical structure with a hollow interior and a top cover; A multi-stage stirring system includes a rotating shaft (3) vertically arranged inside the housing (1) and a plurality of propellers (4) spaced apart along the axial direction on the rotating shaft (3); The precision temperature control system includes a spiral stainless steel coil (7) built into the housing (1) and a black polyurethane sponge layer (5) and a vacuum-plated aluminum film reflective layer (6) wrapped around the outer periphery of the housing (1). The stainless steel coil (7) is connected to an external water bath device (8). The gas-liquid distribution system includes a gas distribution component and a liquid distribution component; the gas distribution component includes a gas mixing chamber (9) connected to a CO2 gas cylinder (12) disposed at the top of the housing (1) and a microporous ceramic diffuser (10) disposed below the gas mixing chamber (9); the liquid distribution component includes a flow-guiding cone hood (16) disposed at the culture medium inlet at the bottom of the peripheral wall of the housing (1), and the flow-guiding cone hood (16) is connected to the liquid storage tank (18) through a pipe.

2. The spiral agitated bioreactor for microbial cultivation and carbon sequestration according to claim 1, characterized in that, The propeller (4) is provided in three parts, each propeller (4) has three blades, which are arranged at 120° intervals along the circumference of the shaft (3) and the blade inclination angle is 15-45°; the axial distance between adjacent propellers (4) is 5cm.

3. The spiral agitated bioreactor for microbial cultivation and carbon sequestration according to claim 1, characterized in that, The top of the rotating shaft (3) is connected to a servo motor (2), which drives it to rotate.

4. The spiral agitated bioreactor for microbial cultivation and carbon sequestration according to claim 1, characterized in that, The gas mixing chamber (9) is connected to the CO2 cylinder (12) via a pipe equipped with a mass flow controller (11), which is also connected to an industrial waste gas pipeline.

5. The spiral agitated bioreactor for microbial cultivation and carbon sequestration according to claim 1, characterized in that, The gas distribution assembly also includes an exhaust port (13) located below the gas mixing chamber (9) of the housing (1).

6. The spiral agitated bioreactor for microbial cultivation and carbon sequestration according to claim 1, characterized in that, The liquid distribution assembly also includes drain ports (15) spaced apart along the height direction of the housing (1).

7. The spiral agitated bioreactor for microbial cultivation and carbon sequestration according to claim 6, characterized in that, The drain port (15) is provided in three places, spaced 5cm apart along the height direction of the shell (1); the drain port (15) is connected to the shell (1) through a pipe equipped with a solenoid valve (14).

8. The spiral agitated bioreactor for microbial cultivation and carbon sequestration according to claim 1, characterized in that, A peristaltic pump (17) is installed on the connecting pipe between the flow guide cone (16) and the liquid storage tank (18).

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