An overflow-type microalgae photobioreactor based on efficient light energy utilization

Abstract

This invention relates to the field of photobioreactor technology and discloses an overflow-type microalgae photobioreactor based on efficient light energy utilization. This reactor includes a container assembly, a circulation assembly, and an aeration assembly. The container assembly includes an outer container and an inner container disposed within the inner cavity of the outer container. The circulation assembly, disposed between the outer container and the inner container, includes a circulation pipe, a circulation pump connected to the circulation pipe, and a nozzle assembly connected to the circulation pipe and extending into the inner container. The aeration assembly has its output end extending into the inner container. This invention is an overflow-type microalgae photobioreactor. Through innovative reactor structure, it can reduce the adverse effects of uneven light energy distribution within the reactor on microalgae cell growth, thereby improving the light exposure of microalgae cells within the reactor and significantly increasing the yield of microalgae biomass and the amount of CO2 fixed.

Description

Technical Field

[0001] This invention relates to the field of photobioreactor technology, and in particular to an overflow microalgae photobioreactor based on the efficient utilization of light energy. Background Technology

[0002] With the rise of the industrial age, fossil fuels such as coal and oil have been widely used globally for various production activities. However, the combustion of fossil fuels results in the emission of large amounts of CO2 into the atmosphere, exacerbating the greenhouse effect. Statistics show that CO2 accounts for as much as 60% of global greenhouse gas emissions, and excessive CO2 emissions causing climate change and global warming pose a significant threat to the ecological environment and human survival. Therefore, CO2 emission reduction technologies have become a hot research topic both domestically and internationally.

[0003] Microalgae are a class of tiny, diverse, single-celled or multicellular organisms capable of photosynthesis. Widely distributed in marine and terrestrial aquatic environments, they possess advantages such as strong environmental adaptability, rapid growth, high photosynthetic efficiency, and rich nutrient content. In recent years, CO2 emission reduction technology based on microalgae cultivation has become one of the main development directions for CO2 emission reduction. This technology utilizes the photosynthesis of microalgae to absorb CO2 and convert it into organic matter, which can not only effectively reduce greenhouse gas emissions but also provide raw materials for the production of biofuels, food, aquatic feed, and health products.

[0004] Microalgae growth requires a suitable photobioreactor. However, as the concentration of microalgae biomass within the reactor gradually increases, the absorption of light energy by microalgae cells and the mutual shading between cells become increasingly severe, leading to a significant reduction in the light transmittance of the microalgae cell suspension. Microalgae cells far from the light incident surface cannot absorb sufficient light to maintain cell proliferation. Therefore, uneven light distribution is a common problem within current photobioreactors, severely limiting the growth of microalgae cells. To reduce the problems of low microalgae biomass yield and decreased CO2 fixation capacity caused by uneven light distribution within the photobioreactor, a common method is to arrange more artificial light sources around the photobioreactor, placing most microalgae cells in the region close to the light incident surface. However, this method suffers from high energy consumption and poor economic efficiency, limiting its development and application. Furthermore, excessively high incident light intensity can damage photosystem II in microalgae photosynthesis, inhibiting cell growth. Therefore, simply increasing the incident light intensity cannot improve the problem of uneven light distribution within the photobioreactor and will also reduce light energy utilization. Summary of the Invention

[0005] The purpose of this section is to outline some aspects of embodiments of the present invention and to briefly describe some preferred embodiments. Simplifications or omissions may be made in this section, as well as in the abstract and title of this application, to avoid obscuring the purpose of these documents; however, such simplifications or omissions should not be construed as limiting the scope of the invention.

[0006] In view of the problems existing in the current microalgae photobioreactors, the present invention is proposed.

[0007] Therefore, the purpose of this invention is to provide an overflow-type microalgae photobioreactor based on efficient utilization of light energy, which is used to solve the problems of low microalgae biomass yield and decreased CO2 fixation capacity caused by uneven light distribution inside the photobioreactor.

[0008] To solve the above-mentioned technical problems, the present invention provides the following technical solution: an overflow microalgae photobioreactor based on efficient utilization of light energy. This reactor includes a container assembly, a circulation assembly, and an air supply assembly. The container assembly includes an outer container and an inner container disposed within the inner cavity of the outer container. The circulation assembly is disposed between the outer container and the inner container and includes a circulation pipe, a circulation pump connected to the circulation pipe, and a nozzle assembly connected to the circulation pipe and extending into the inner container. The air supply assembly has its output end extending into the inner container.

[0009] As a preferred embodiment of the overflow microalgae photobioreactor based on efficient utilization of light energy described in this invention, the height of the outer container is greater than the height of the inner container, and the cavity between the outer container and the inner container and the inner container are both filled with microalgae cell suspension.

[0010] As a preferred embodiment of the overflow microalgae photobioreactor based on efficient utilization of light energy described in this invention, wherein the liquid level of the microalgae cell suspension in the inner container is greater than the liquid level of the microalgae cell suspension in the cavity.

[0011] As a preferred embodiment of the overflow microalgae photobioreactor based on efficient utilization of light energy described in this invention, wherein: a guide plate extends outward from the circumferential sidewall of the top opening of the inner container, and the height of one end of the guide plate extending outward is lower than the height of the top opening of the inner container and not less than the liquid level of the microalgae cell suspension in the cavity.

[0012] As a preferred embodiment of the overflow microalgae photobioreactor based on efficient utilization of light energy described in this invention, wherein: the input end of the circulation pipe is connected to the cavity, and its output end is connected to the input interface of the nozzle assembly.

[0013] As a preferred embodiment of the overflow microalgae photobioreactor based on efficient utilization of light energy described in this invention, the nozzle group is disposed in the bottom region of the inner container, and further includes several groups of uniformly distributed nozzles connected to the input interface.

[0014] As a preferred embodiment of the overflow microalgae photobioreactor based on efficient utilization of light energy described in this invention, the gas supply component includes a gas supply pipe, a gas supply branch pipe connected to the output end of the gas supply pipe, and an aerator disposed at the output end of the gas supply branch pipe.

[0015] As a preferred embodiment of the overflow microalgae photobioreactor based on efficient utilization of light energy described in this invention, the aerators and nozzles are of the same number and correspond one-to-one, and the aerators are located directly above the corresponding nozzles.

[0016] As a preferred embodiment of the overflow microalgae photobioreactor based on efficient utilization of light energy described in this invention, the gas supply pipe is filled with a gas rich in carbon dioxide.

[0017] As a preferred embodiment of the overflow microalgae photobioreactor based on efficient utilization of light energy described in this invention, the incident light irradiates the microalgae cell suspension from directly above the outer container.

[0018] The beneficial effects of this invention are:

[0019] This invention is an overflow-type microalgae photobioreactor. Through innovative reactor structure, it can reduce the adverse effects of uneven light energy distribution inside the reactor on the growth of microalgae cells, thereby improving the light exposure of microalgae cells in the reactor and significantly increasing the yield of microalgae biomass and the amount of CO2 fixed. Attached Figure Description

[0020] To more clearly illustrate the technical solutions of the embodiments of the present invention, the drawings used in the description of the embodiments will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort. Wherein:

[0021] Figure 1 This is a schematic diagram of the connection structure of the container assembly, circulation assembly, and gas supply assembly of the overflow microalgae photobioreactor based on the efficient utilization of light energy of the present invention.

[0022] Figure 2 This is a schematic diagram of the overall structure of the overflow microalgae photobioreactor based on the efficient utilization of light energy according to the present invention.

[0023] Figure 3This is a schematic diagram showing the flow direction of microalgal cell suspension and CO2 during the application of the overflow microalgal photobioreactor based on the efficient utilization of light energy of the present invention.

[0024] Figure 4 This is a top view schematic diagram of the overflow microalgae photobioreactor based on the efficient utilization of light energy according to the present invention. Detailed Implementation

[0025] To make the above-mentioned objects, features and advantages of the present invention more apparent and understandable, the specific embodiments of the present invention will be described in detail below with reference to the accompanying drawings.

[0026] Many specific details are set forth in the following description in order to provide a full understanding of the invention. However, the invention may also be practiced in other ways different from those described herein, and those skilled in the art can make similar extensions without departing from the spirit of the invention. Therefore, the invention is not limited to the specific embodiments disclosed below.

[0027] Secondly, the term "one embodiment" or "embodiment" as used herein refers to a specific feature, structure, or characteristic that may be included in at least one implementation of the present invention. The phrase "in one embodiment" appearing in different places in this specification does not necessarily refer to the same embodiment, nor is it a single or selective embodiment that is mutually exclusive with other embodiments.

[0028] Secondly, the present invention is described in detail with reference to the schematic diagrams. When detailing the embodiments of the present invention, for ease of explanation, the cross-sectional views illustrating the device structure may be partially enlarged, not according to the usual scale. Furthermore, the schematic diagrams are merely examples and should not limit the scope of protection of the present invention. In addition, actual fabrication should include three-dimensional spatial dimensions of length, width, and depth.

[0029] Example 1

[0030] Reference Figures 1-4 The first embodiment of the present invention provides an overflow microalgae photobioreactor based on efficient utilization of light energy. The reactor includes a container assembly 100, a circulation assembly 200, and an aeration assembly 300. The container assembly 100 is a container for holding a microalgae cell suspension in the reactor; the circulation assembly 200 is used for circulating the microalgae cell suspension in the container; and the aeration assembly 300 is used to supply CO2 gas to the microalgae cell suspension.

[0031] Specifically, the container assembly 100 includes an outer container 101 and an inner container 102 disposed within the inner cavity of the outer container. The outer container 101 and the inner container 102 can be arranged coaxially or diaxially, and can be an integral or separate structure; there is no specific limitation in this regard. Similarly, the radial cross-sectional shape of the inner and outer containers is not specifically limited and can be circular, square, triangular, etc.; in this design, a coaxial integral cylindrical structure is preferred.

[0032] Furthermore, the height of the outer container 101 is greater than the height of the inner container 102. Both the cavity R between the outer container 101 and the inner container 102 and the inner container 102 contain microalgae cell suspension Y. The liquid level of the microalgae cell suspension Y in the inner container 102 must be greater than the liquid level of the microalgae cell suspension Y in the cavity R. Since the flow rate of the microalgae cell suspension injected into the inner chamber 102 during operation is always equal to the flow rate of the microalgae cell suspension flowing into the outer chamber 101, meaning the liquid levels in both the inner and outer chambers remain constant, ensuring that the liquid level in the inner chamber 102 just reaches the top of the inner chamber 102 and is higher than the liquid level in the cavity R before reactor operation is sufficient to guarantee the normal operation of the overflow microalgae photobioreactor. The suspensions in both chambers are kept in circulation through the circulation component 200.

[0033] For the inner container 102, a guide plate 102a extends outward from the circumferential sidewall of its top opening. The height of the outwardly extending end of the guide plate 102a is lower than the height of the top opening of the inner container 102, but not less than the liquid level of the microalgae cell suspension Y in the cavity R. Specifically, the guide plate 102a has a ring-shaped structure, extending outward from the circumferential sidewall of the top opening of the inner container 102 for a certain width. The height of the outwardly extending end is slightly lower, and the ring surface can be concave, convex, or planar. In this embodiment, a convex guide plate structure is shown and described.

[0034] Here, the guide plate 102a is used to increase the flow area of ​​the suspension and reduce the liquid layer thickness of the suspension, so that the microalgal cell suspension Y overflowing from the inner container 102 forms a thin liquid film along the upper surface of the guide plate 102a and continues to flow towards the cavity R under the action of gravity; therefore, the annular width of the guide plate 102a can be appropriately increased, and its lower end height is not below the liquid surface of the suspension in the cavity R.

[0035] Furthermore, the circulation assembly 200 is disposed between the outer container 101 and the inner container 102, and includes a circulation pipe 201, a circulation pump 202 connected in the circulation pipe 201, and a nozzle assembly 203 connected to the circulation pipe 201 and extending into the inner container 102; wherein, the input end of the circulation pipe 201 is connected to the cavity R, and its output end is connected to the input interface 203a of the nozzle assembly 203.

[0036] The nozzle assembly 203 is located in the bottom area of ​​the inner container 102, and it also includes several groups of evenly distributed nozzles 203b that are connected to the input interface 203a.

[0037] It should be noted that the circulation pipe 201 is used to connect the inner container 102 and the cavity R. It can be located outside the container assembly 100 or inside the cavity R, depending on the specific reactor structure. The circulation pump 202 provides the power for liquid circulation. Driven by the circulation pump 202, the microalgal cell suspension Y flowing to the outer cavity 101 will re-enter the inner cavity 102, forming a circulating flow of the microalgal cell suspension. This circulating flow continuously moves the microalgal cell suspension from the bottom of the inner cavity 102, away from the light incident surface, to the top of the inner cavity 102, closer to the light incident surface. This accelerates the circulation of microalgal cells between the light-saturated and light-deficient areas, allowing more microalgal cells to fully absorb light energy for photosynthesis in the light-saturated area, providing the necessary energy for microalgal cell growth. In particular, it improves the light exposure of microalgal cells originally located at the bottom of the inner cavity 102. Meanwhile, during the circulation process, the thin liquid film formed along the upper surface of the guide plate by the microalgae cell suspension can effectively increase the contact area between the microalgae cells and the light, improve the light energy utilization rate, and provide sufficient light for the growth of microalgae cells.

[0038] The nozzle assembly 203 is located at or near the bottom of the inner container 102. To ensure the smooth flow of the suspension, the nozzle assembly 203 has multiple nozzles 203b, which are evenly distributed.

[0039] Furthermore, in order to ensure that the microalgal cell suspension Y in the inner chamber 102 flows upward evenly and that more microalgal cells can reach the light-saturated area, this scheme installs a valve F at the lower end of each nozzle 203b. The valve F of each nozzle 203b can be independently controlled, thereby adjusting the flow rate of the microalgal cell suspension injected into the inner chamber 102 by each nozzle 203b.

[0040] The CO2 required for photosynthesis in microalgae cells is delivered to the inner container 102 via an aeration assembly 300. Specifically, the aeration assembly 300 includes an aeration pipe 301, an aeration branch pipe 302 connected to the output end of the aeration pipe 301, and an aerator 303 located at the output end of the aeration branch pipe 302. The aeration pipe 301 carries a gas rich in carbon dioxide. The aeration pipe 301 delivers external CO2 to the aeration branch pipe 302, which is then discharged via the aerator 303. The aerator 303 generates a large number of CO2-rich bubbles that are released into the microalgae cell suspension and dissolve in the microalgae cell suspension Y, providing raw materials for microalgae cell photosynthesis.

[0041] Furthermore, the number of aerators 303 and nozzles 203b are the same and correspond one-to-one, and the aerators 303 are located directly above and close to the corresponding nozzles 203b; therefore, the microalgae cell suspension Y sprayed into the inner chamber 102 by the nozzles 203b can be flushed and broken by the flow action, increasing the gas-liquid contact area, promoting the dissolution of CO2 in the microalgae cell suspension Y, and providing sufficient inorganic carbon for the photosynthetic carbon fixation growth of microalgae cells in the reactor.

[0042] For incident light G, it is chosen to irradiate the microalgal cell suspension Y from directly above the outer container 101.

[0043] Example 2

[0044] This is a second embodiment of the present invention, which is an example of applying the reactor from Embodiment 1:

[0045] Specifically, Scenedesmus obliqueis, which has a fast biological growth rate and high oil content, was selected as the algae species. The microalgal cell suspension Y was selected from BG11 culture medium. The outer container 101 and the inner container 102 were cylindrical chamber structures. The circulation pipe 201 was a silicone tube with an inner diameter of 8 mm. The valve F was a shut-off valve. The gas supply pipe 301 was a PVC pipe with an inner diameter of 6 mm. The volume percentage concentration of CO2 gas was 10%. The aerator 303 was a ceramic aeration stone with an average pore size of 5 mm and a diameter of 1 cm. The guide plate 102a was an organic glass plate with a convex structure. The circulation pump 202 was a submersible pump.

[0046] In this specific embodiment, the microalgae cell suspension Y, driven by the circulation pump 202, flows from the outer container 101 to the nozzle 203b along the circulation pipe 201, and is sprayed into the inner container 102 through the nozzle 203b. This propels the microalgae cell suspension Y in the inner container 102 to flow from bottom to top. The microalgae cell suspension at the bottom of the inner container 102 flows to the top of the inner container 102, which is closer to the incident light G, allowing the microalgae cells in the light-deficient area to enter the light-sufficient area. Meanwhile, the microalgae cell suspension Y at the top of the inner container 102 overflows from the top of the inner container 102 under the action of the flow, forming a thin liquid film along the upper surface of the guide plate 102a, increasing the contact area between the microalgae cell suspension Y and the incident light G. Then, under the action of gravity, it continues to flow to the outer container 101, completing one cycle of the microalgae cell suspension and entering the next cycle.

[0047] The CO2 required for photosynthesis by microalgae cells is delivered to aerator 303 via gas supply pipe 301. Aerator 303 generates a large number of CO2-rich bubbles that enter the microalgae cell suspension Y. Under the flushing action of the microalgae cell suspension injected into the inner container 102 by nozzle 203b, the large number of CO2-rich bubbles are broken up, increasing the gas-liquid contact area, promoting the dissolution of CO2 in the microalgae cell suspension Y, and improving the efficiency of microalgae cell photosynthesis. Through the coordinated operation of all components, the overflow-type microalgae photobioreactor achieves highly efficient utilization of light energy.

[0048] 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. Although the present invention has been described in detail with reference to preferred embodiments, those skilled in the art should understand that modifications or equivalent substitutions can be made to the technical solutions of the present invention without departing from the spirit and scope of the technical solutions of the present invention, and all such modifications or substitutions should be covered within the scope of the claims of the present invention.

Claims

1. An overflow-type microalgae photobioreactor based on efficient light energy utilization, characterized in that: include, A container assembly (100) includes an outer container (101) and an inner container (102) disposed within the cavity of the outer container. A circulation assembly (200), disposed between the outer container (101) and the inner container (102), includes a circulation pipe (201), a circulation pump (202) connected to the circulation pipe (201), and a nozzle assembly (203) connected to the circulation pipe (201) and extending into the inner container (102); and, An air supply assembly (300) has its output end extending into the inner container (102); The height of the outer container (101) is greater than the height of the inner container (102), and the cavity (R) between the outer container (101) and the inner container (102) and the inner container (102) are both filled with microalgae cell suspension (Y). The liquid level of the microalgal cell suspension (Y) in the inner container (102) is greater than the liquid level of the microalgal cell suspension (Y) in the cavity (R); A guide plate (102a) extends outward from the circumferential sidewall of the top opening of the inner container (102). The height of the outwardly extending end of the guide plate (102a) is lower than the height of the top opening of the inner container (102) and not less than the liquid level of the microalgal cell suspension (Y) in the cavity (R). The input end of the circulation pipe (201) is connected to the cavity (R), and its output end is connected to the input interface (203a) of the nozzle assembly (203). The nozzle assembly (203) is located in the bottom region of the inner container (102), and it also includes several sets of evenly distributed nozzles (203b) that are connected to the input interface (203a). The air supply assembly (300) includes an air supply pipe (301), an air supply branch pipe (302) connected to the output end of the air supply pipe (301), and an aerator (303) disposed at the output end of the air supply branch pipe (302). The number of aerators (303) and nozzles (203b) are the same and correspond one-to-one, and the aerators (303) are located directly above the corresponding nozzles (203b). Gas rich in carbon dioxide is introduced into the gas supply pipe (301); Incident light (G) shines on the microalgal cell suspension (Y) from directly above the outer container (101).

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