Microalgae biological culture device and method

Abstract

The invention discloses a microalgae biological culture device and method. The culture device comprises a support and a funnel-shaped round cylinder arranged on the support, a pointed cone is arranged in the center of the funnel-shaped round cylinder, flow guide twisted lines are arranged on the pointed cone, a circulating water injection pipe is arranged on the side wall of the funnel-shaped round cylinder, and a culture water input pipe and a microalgae output pipe are arranged at the bottom of the funnel-shaped round cylinder. The culture method comprises the following steps: pumping culture water into a funnel-shaped cylinder through a culture water input pipe until a target volume is reached, inoculating microalgae, and circularly injecting the culture water into the top of the funnel-shaped cylinder from the bottom of the funnel-shaped cylinder through a circulating water injection pipe to form an inward vortex, so that the microalgae grow; and after the growth is finished, closing the circulating water injection pipe, naturally standing, gathering the microalgae concentrated solution to the central position of the funnel-shaped cylinder, and collecting from the microalgae output pipe. According to the invention, through the funnel-shaped cylinder, the circulating water injection pipe and the flow guide twisted lines, the algae-water mixed liquid forms an inward vortex in the funnel-shaped cylinder, no additional energy waste for stirring is needed, and the cost is reduced.

Description

Technical Field

[0001] This invention belongs to the field of algae cultivation technology, specifically relating to a microalgae biological cultivation device and method. Background Technology

[0002] Microalgae are a type of single-celled or simple multicellular photosynthetic microorganisms with high photosynthetic efficiency, fast growth rate and strong environmental adaptability. Their stem-based cells contain more than 50% protein and are rich in high-value bioactive substances such as DHA, EPA, astaxanthin and β-carotene. They are widely used in food, feed, medicine, cosmetics, bioenergy and CO2 emission reduction.

[0003] Currently, microalgae cultivation mainly adopts two modes: (1) open raceway pond: water circulation is driven by paddle wheels installed in artificial or natural ponds, which is simple in structure and low in investment; (2) closed photobioreactor: mostly tubular, flat or column type, controlled cultivation is achieved by artificial light source or natural light irradiation. However, the existing cultivation methods have the following shortcomings: (1) long cycle: due to the low light transmittance of raceway ponds, the cell doubling time is generally >3 days, making it difficult to further shorten the batch cycle; (2) large footprint: the effective water depth of raceway ponds is only 0.2-0.3m, and the biomass yield per unit area is less than 10g / m². 2 / d; Tubular reactors require long-distance coils to meet ton-level production, resulting in low land utilization; (3) High cost: Tubular reactors are expensive, circulating pumps consume a lot of energy, and closed pipes are inconvenient to clean, all of which increase the cost of microalgae cultivation. Therefore, it is of great significance to develop a microalgae biological cultivation device and method that is small in size, short in cycle, and low in cost. Summary of the Invention

[0004] To address the shortcomings of existing methods, this invention provides a microalgae culture device and method.

[0005] To achieve the above objectives, the present invention adopts the following technical solution: A microalgae culture device includes a support frame and a funnel-shaped cylinder mounted on the support frame. The funnel-shaped cylinder has a pointed cone at its center and a flow-guiding twist on the pointed cone. The side wall of the funnel-shaped cylinder is provided with several circulating water injection pipes, and the bottom of the funnel-shaped cylinder is provided with a culture water input pipe and a microalgae output pipe.

[0006] Preferably, the outer circular surface of the vertebral body is provided with several sets of flow-guiding twists from top to bottom, with three flow-guiding twists in each set, which are inclined around the outer circular surface of the vertebral body, and the length of the flow-guiding twists gradually increases from top to bottom as the diameter of the vertebral body increases.

[0007] Preferably, the circulating water pipe is composed of an upper horizontal water pipe, a vertical water pipe and a lower horizontal water pipe. The vertical water pipe is installed on the side wall of the funnel-shaped cylinder. The lower horizontal water pipe is connected to the bottom of the funnel-shaped cylinder. The upper horizontal water pipe is installed at the top of the funnel-shaped cylinder and is set at an angle of 15-40° to the tangent direction of the outer circular surface of the funnel-shaped cylinder.

[0008] Preferably, the microalgae output pipe is located at the bottom of the funnel-shaped cylinder, the bottom of the conical body is fixed to the funnel-shaped cylinder, and the bottom of the conical body is also provided with several through holes, all of which are connected to the microalgae output pipe.

[0009] The microalgae culture method using the above-mentioned culture device includes the following steps: S1. Pump the culture water into the funnel-shaped cylinder through the culture water inlet pipe until the target volume is reached, then inoculate with microalgae. Open the circulation water pipe and circulate the culture water from the bottom to the top of the funnel-shaped cylinder through the circulation water pipe. A vortex is formed inward in the funnel-shaped cylinder, and the microalgae grow. S2. After growth ends, close the circulating water pipe and let it stand naturally. The microalgae concentrate will gather in the center of the funnel-shaped cylinder and be collected from the microalgae output pipe at the bottom of the funnel-shaped cylinder.

[0010] Preferably, the microalgae include one or a mixture of several of Chlorella, cyanobacteria, green algae, diatoms, and dinoflagellates.

[0011] Preferably, the aquaculture water is fishpond tailings water, and the nitrogen concentration in the fishpond tailings water is 10-30 mg / L and the phosphorus concentration is 1-10 mg / L.

[0012] Preferably, the flow rate of aquaculture water in the circulating water injection pipe in step S1 is 0.5-1.5 L / min.

[0013] Preferably, the temperature for microalgae growth in step S1 is 16-27℃, the pH is 6.0-8.5, the growth time is 12-18h, and the light intensity is 2000-5000lx.

[0014] Preferably, the lighting for microalgae growth in step S1 is natural light and / or LED lighting.

[0015] The positive and beneficial effects of this invention are: 1. The microalgae culture device of the present invention includes a funnel-shaped cylinder, a circulating water injection pipe arranged around it, and a flow-guiding twist on the conical body. During the microalgae culture process, the algae-water mixture is continuously injected from the bottom to the top of the funnel-shaped cylinder through the circulating water injection pipe, forming an inward vortex in the funnel-shaped cylinder, which slowly rotates back to the lower center. After the culture is completed, the microalgae continue to gather and concentrate towards the center under the action of gravity, without the need for additional energy wasted on stirring. In addition, fishpond tailwater is used as the aquaculture water, which reduces the cost. Moreover, the culture device of the present invention has a small footprint, a short culture cycle, and is easy to implement widely.

[0016] 2. This invention controls the flow rate and shear strength of the vortex formed by the algae-water mixture by adjusting the angle of the upper horizontal water pipe of the circulating water injection pipe and the flow rate of the aquaculture water in the circulating water injection pipe, in conjunction with the funnel-shaped structure of the cylinder and the flow-guiding twist, thereby providing power for the suspended growth of microalgae. This allows the same device to be adapted to different algae species, thus broadening the scope of application.

[0017] 3. During the flow of the algae-water mixture, the present invention forms a vortex, which dissolves oxygen and carbon dioxide from the air into the aquaculture water, providing the microalgae with the gases needed for growth and photosynthesis, realizing gas-liquid self-absorption of dissolved oxygen. The surface of the vortex liquid is periodically exposed to air, and the low-pressure zone of the vortex core entrains O2 / CO2, eliminating the need for blowers or micropore aeration, reducing total power consumption, saving costs, reducing carbon footprint, and simultaneously completing carbon source replenishment. Attached Figure Description

[0018] Figure 1 A three-dimensional view of a microalgae culture device; Figure 2 This is a cross-sectional view of a microalgae culture device. Figure 3 This is a diagram illustrating the microalgae production process in Example 2 of the present invention. Figure 4 This is a diagram illustrating the microalgae production process in Example 3 of the present invention. In the diagram: 1-Support, 2-Funnel-shaped cylinder, 3-Conical body, 4-Guiding twist, 5-Circulating water pipe, 51-Upper horizontal water pipe, 52-Vertical water pipe, 53-Lower horizontal water pipe, 6-Aquaculture water input pipe, 7-Microalgae output pipe, 8-Pump 1, 9-Valve 1, 10-Pump 2, 11-Valve 2, 12-Valve 3, 13-Through hole. Detailed Implementation

[0019] The present invention will be further described below with reference to some specific embodiments.

[0020] Example 1 See Figure 1 and Figure 2A microalgae culture device includes a support frame 1 and a funnel-shaped cylinder 2 mounted on the support frame 1. A pointed cone 3 is located at the center of the funnel-shaped cylinder 2, and flow-guiding twists 4 are provided on the pointed cone 3. Four circulating water pipes 5 are evenly arranged on the sidewalls of the funnel-shaped cylinder 2. A culture water inlet pipe 6 and a microalgae outlet pipe 7 are located at the bottom of the funnel-shaped cylinder 2. The flow-guiding twists act as "flow-guiding ribs," providing centripetal force for the vortex formed by the algae-water mixture. A pump 8 and a valve 9 are installed on the circulating water pipes 5. During the microalgae culture process, the algae-water mixture is circulated from the bottom to the top of the funnel-shaped cylinder through the circulating water pipes 5. Working synergistically with the funnel-shaped structure of the cylinder and the flow-guiding twists, the algae-water mixture forms an inward-facing vortex within the funnel-shaped cylinder, slowly swirling towards the lower center, eliminating the need for additional energy-consuming stirring. Pump 2 10 and valve 2 11 are installed on the aquaculture water inlet pipe 6, and valve 3 12 is installed on the microalgae outlet pipe 7. Before microalgae cultivation, the required aquaculture water is injected into the funnel-shaped cylinder 2 through the aquaculture water inlet pipe 6. After microalgae cultivation, the microalgae concentrate is collected from the microalgae outlet pipe 7.

[0021] Furthermore, four sets of flow-guiding twists 4 are arranged from top to bottom on the outer circular surface of the pointed cone 3. Each set of flow-guiding twists consists of three twists, which are inclined around the outer circular surface of the pointed cone 3. Each flow-guiding twist has one end higher than the other end. The length of each set of flow-guiding twists 4 gradually increases from top to bottom as the diameter of the pointed cone 3 increases.

[0022] Furthermore, the circulating water pipe 5 is composed of an upper horizontal water pipe 51, a vertical water pipe 52, and a lower horizontal water pipe 53. The vertical water pipe 52 is installed on the side wall of the funnel-shaped cylinder 2. The lower horizontal water pipe 53 is connected to the bottom of the funnel-shaped cylinder 2. The upper horizontal water pipe 51 is installed at the top of the funnel-shaped cylinder 2 and is set at 30° with the tangent direction of the outer circle of the funnel-shaped cylinder. Pump 8 is installed on the lower horizontal water pipe 53, and valve 9 is installed on the upper horizontal water pipe 51.

[0023] Furthermore, the microalgae output pipe 7 is located at the bottom of the funnel-shaped cylinder 2, the culture water input pipe 6 is located above the microalgae output pipe 7, the bottom of the conical body 3 is fixed to the funnel-shaped cylinder 2, and four through holes 13 are evenly opened at the bottom of the conical body 3. Each through hole 13 is connected to the microalgae output pipe 7. After the microalgae culture is completed, the microalgae concentrate flows from the four through holes 13 into the microalgae output pipe 7 for collection.

[0024] Example 2 A method for cultivating microalgae using the microalgae cultivation apparatus described in Example 1 includes the following steps: S1. Liquid Injection and Inoculation: Turn on pump 2 10 and valve 2 11 on the culture water inlet pipe 6 to pump the culture water into the funnel-shaped cylinder 2 through the culture water inlet pipe 6. After reaching the required volume, turn off pump 2 10 and valve 2 11. Inoculate Chlorella at an algal density of 4000 cells / mL and then culture at 24℃ and pH 7.4±0.2. The aquaculture water is the tailwater of fish ponds, with a nitrogen concentration of 10 mg / L, a phosphorus concentration of 4 mg / L, and a nitrogen-to-phosphorus ratio of 2.5:1. S2. Cultivation: Open valve 9 on the upper horizontal water pipe 51 and pump 8 on the lower horizontal water pipe 52 to circulate the culture water from the bottom of the funnel-shaped cylinder 2 to the top. The flow rate of the culture water is 1L / min, which allows the algae-water mixture in the device to form an inward vortex and slowly swirl back to the lower center. The Chlorella is in a suspended state. At the same time, the upper horizontal water pipe 51 is higher than the culture water surface. During the process of injecting culture water, air is injected into the water to provide photosynthesis for the Chlorella. During the day, the light intensity is controlled at 2000-5000 lx. At night or below 1000 lx, turn on the LED lighting to supplement the light. The LED light is blue light + red light (1:1, 2000 lx). Red light (600-700nm) helps microalgae mature and increases the accumulation of intracellular dissolved substances. Blue light (400-500nm) promotes vegetative growth, stimulates chlorophyll synthesis, and enhances photosynthesis. With the combined effect of blue and red light, the photosynthetic rate is increased.

[0025] S3. Harvesting: After 16 hours of cultivation and maturation, close valve 9 on the upper horizontal water pipe 51 and pump 8 on the lower horizontal water pipe 52, turn off the light source, and let it stand naturally for 6 hours. Under the action of gravity, the Chlorella concentrate will continue to gather at the bottom of the funnel-shaped cylinder. Open valve 12 on the microalgae output pipe 7 to collect it. S4. Monitoring: The concentration of Chlorella in the water body is measured using OD. 680 The concentration was monitored at nm, with samples taken every 2 hours. The concentration was converted to algal cell concentration, and an S-growing curve was plotted. Figure 3 As shown. By Figure 3 It can be seen that the adaptation period of Chlorella is shortened and its population increases rapidly. It enters a plateau phase at 16 hours, and the algal density can reach 51,000 cells / mL.

[0026] Example 3 A method for cultivating microalgae using the microalgae cultivation apparatus described in Example 1 includes the following steps: S1. Liquid Injection and Inoculation: Turn on pump 2 10 and valve 2 11 on the culture water inlet pipe 6 to pump the culture water into the funnel-shaped cylinder 2 through the culture water inlet pipe 6. After reaching the required volume, turn off pump 2 10 and valve 2 11. Inoculate Chlorella and Dinoflagellate at a ratio of 1:1 to 4000 cells / mL, and then culture at 24℃ and pH 7.4±0.2. Among them, the aquaculture water is the tail water of fish ponds, with a nitrogen concentration of 20 mg / L, a phosphorus concentration of 4 mg / L, and a nitrogen-to-phosphorus ratio of 5:1. S2. Cultivation: Open valve 9 on the upper horizontal water pipe 51 and pump 8 on the lower horizontal water pipe 52 to circulate the culture water from the bottom of the funnel-shaped cylinder 2 to the top. The flow rate of the culture water is 1L / min, which allows the algae-water mixture in the device to form an inward vortex and slowly swirl back to the lower center. Chlorella and dinoflagellates are in a suspended state. At the same time, the upper horizontal water pipe 51 is higher than the culture water surface. During the process of injecting culture water, air is injected into the water to provide photosynthesis for Chlorella and dinoflagellates. During the day, the light intensity is controlled at 2000-5000 lx. At night or below 1000 lx, turn on the LED lighting to supplement the light. The LED light is blue light + red light (1:1, 2000 lx). Red light (600-700nm) helps microalgae mature and increases the accumulation of intracellular dissolved substances. Blue light (400-500nm) promotes vegetative growth, stimulates chlorophyll synthesis, and enhances photosynthesis. With the combined effect of blue and red light, the photosynthetic rate is increased. S3. Harvesting: After 18 hours of cultivation and maturation, close valve 9 on the upper horizontal water pipe 51 and pump 8 on the lower horizontal water pipe 52, turn off the light source, and let it stand naturally for 6 hours. The concentrated liquid of Chlorella and Dinoflagellate will continue to gather at the bottom of the funnel-shaped cylinder under the action of gravity. Open valve 12 on the microalgae output pipe 7 to collect it. S4. Monitoring: The concentration of Chlorella in the water body is measured using OD. 680 The concentration was monitored at nm, with samples taken every 2 hours. The concentration was converted to algal cell concentration, and an S-growing curve was plotted. Figure 4 As shown. By Figure 4 It can be seen that the adaptation period of Chlorella and Dinoflagellate is shortened and they multiply rapidly, entering a plateau phase at 18 hours, with an algal density of up to 52,000 cells / mL.

[0027] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention and are not intended to limit it. Any other modifications or equivalent substitutions made by those skilled in the art to the technical solutions of the present invention, as long as they do not depart from the spirit and scope of the technical solutions of the present invention, should be covered within the scope of the claims of the present invention.

Claims

1. A microalgae culture device, characterized in that, The device includes a support frame and a funnel-shaped cylinder mounted on the support frame. The funnel-shaped cylinder has a pointed cone at its center with flow-guiding twisted grooves on the cone. The side wall of the funnel-shaped cylinder is provided with several circulating water injection pipes, and the bottom of the funnel-shaped cylinder is provided with an aquaculture water input pipe and a microalgae output pipe.

2. The microalgae culture device according to claim 1, characterized in that, The outer circular surface of the vertebral body is provided with several sets of guiding twists from top to bottom. Each set of guiding twists consists of three twists, which are inclined around the outer circular surface of the vertebral body. The length of the guiding twists gradually increases from top to bottom as the diameter of the vertebral body increases.

3. The microalgae culture device according to claim 1, characterized in that, The circulating water injection pipe consists of an upper horizontal water pipe, a vertical water pipe, and a lower horizontal water pipe. The vertical water pipe is installed on the side wall of the funnel-shaped cylinder. The lower horizontal water pipe is connected to the bottom of the funnel-shaped cylinder. The upper horizontal water pipe is installed at the top of the funnel-shaped cylinder and is set at an angle of 15-40° to the tangent direction of the outer circular surface of the funnel-shaped cylinder.

4. The microalgae culture device according to any one of claims 1-3, characterized in that, The microalgae output pipe is located at the bottom of the funnel-shaped cylinder. The bottom of the cone is fixed to the funnel-shaped cylinder. Several through holes are also provided at the bottom of the cone, and all the through holes are connected to the microalgae output pipe.

5. A method for microalgae cultivation using the cultivation apparatus according to any one of claims 1-4, characterized in that, Includes the following steps: S1. Pump the culture water into the funnel-shaped cylinder through the culture water inlet pipe until the target volume is reached, then inoculate with microalgae. Circulate the culture water from the bottom to the top of the funnel-shaped cylinder through the circulation water injection pipe. A vortex is formed inward in the funnel-shaped cylinder, allowing the microalgae to grow. S2. After growth ends, close the circulating water pipe and let it stand naturally. The microalgae concentrate will gather in the center of the funnel-shaped cylinder and be collected from the microalgae output pipe at the bottom of the funnel-shaped cylinder.

6. The microalgae culture method according to claim 5, characterized in that, The microalgae include one or a mixture of several of the following: Chlorella, cyanobacteria, green algae, diatoms, and dinoflagellates.

7. The microalgae culture method according to claim 5, characterized in that, The aquaculture water is fishpond tailings, and the nitrogen concentration in the fishpond tailings is 10-30 mg / L and the phosphorus concentration is 1-10 mg / L.

8. The microalgae culture method according to claim 5, characterized in that, The flow rate of aquaculture water in the circulating water injection pipe in step S1 is 0.5-1.5 L / min.

9. The microalgae culture method according to claim 5, characterized in that, The microalgae growth in step S1 is carried out at a temperature of 16-27℃, a pH of 6.0-8.5, a growth time of 12-18h, and a light intensity of 2000-5000lx.

10. The microalgae culture method according to claim 9, characterized in that, The lighting for microalgae growth in step S1 is natural light and / or LED lighting.

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