Overflow type microalgae photobioreactor based on efficient utilization of light energy

Abstract

The invention relates to the technical field of photobioreactors, and discloses an overflow type microalgae photobioreactor based on efficient utilization of light energy, the reactor comprises a container assembly, a circulation assembly and a gas supply assembly, the container assembly comprises an outer container and an inner container arranged in an inner cavity of the outer container; the circulating assembly is arranged between the outer container and the inner container and comprises a circulating pipe, a circulating pump connected into the circulating pipe and a spray head group connected with the circulating pipe and extending into the inner container; the output end of the air supply assembly extends into the inner container; according to the overflow type microalgae photobioreactor, the adverse effect of uneven light energy distribution in the reactor on the growth of microalgae cells can be reduced through structural innovation of the reactor, so that the light receiving condition of the microalgae cells in the reactor is improved, and the yield of microalgae biomass and the fixed amount of CO2 are greatly increased.

Description

Technical Field

[0001] The invention relates to the technical field of photobioreactors, and in particular to an overflow type microalgae photobioreactor based on efficient utilization of light energy. Background Art

[0002] With the rise of the industrial age, fossil fuels such as coal and oil are widely used in various production activities around the world. However, the combustion of fossil fuels leads to a large amount of CO2 being emitted into the atmosphere, which intensifies the greenhouse effect. According to statistics, CO2 accounts for as much as 60% of the greenhouse gases emitted globally. Climate change and global warming caused by excessive CO2 emissions pose a huge threat to the ecological environment and human survival. Therefore, CO2 emission reduction technology has become a hot topic of research at home and abroad.

[0003] Microalgae are a type of single-cell or multi-cell organisms that are tiny, diverse, and capable of photosynthesis. They are widely distributed in aquatic environments on land and sea. They have the advantages of strong environmental adaptability, fast growth, high photosynthesis efficiency, and rich nutrition. In recent years, CO2 emission reduction technology based on microalgae cultivation has become one of the main development directions of CO2 emission reduction. This technology uses the photosynthesis of microalgae to absorb CO2 and convert it into organic matter. It can not only effectively reduce greenhouse gas emissions, but also provide raw materials for the production of biofuels, food, aquatic feed, health products, etc.

[0004] The growth of microalgae needs to be carried out in a suitable photobioreactor. However, as the concentration of microalgae biomass in the reactor gradually increases, the absorption of light energy by microalgae cells and the mutual shielding between cells become more and more serious, resulting in a significant reduction in the light transmittance of the microalgae cell suspension. The microalgae cells far away from the light incident surface cannot absorb enough light to maintain cell proliferation. Therefore, there is a common problem of uneven light distribution inside the current photobioreactor, which greatly limits the growth of microalgae cells in the photobioreactor. In order to reduce the problem of low microalgae biomass yield and reduced CO2 fixation capacity caused by uneven light distribution inside the photobioreactor, a common method is to arrange more artificial light sources around the photobioreactor so that most of the microalgae cells are in the area close to the light incident surface. However, this method has the problems of high energy consumption and poor economy, which limits its development and application. In addition, too high incident light intensity will damage the photosystem II in the photosynthesis of microalgae cells and inhibit the growth of microalgae cells. Therefore, simply increasing the incident light intensity cannot improve the problem of uneven light energy distribution in the photobioreactor, and will cause a decrease in light energy utilization. Summary of the invention

[0005] The purpose of this section is to summarize some aspects of embodiments of the present invention and briefly introduce some preferred embodiments. Some simplifications or omissions may be made in this section and the specification abstract and the invention title of this application to avoid blurring the purpose of this section, the specification abstract and the invention title, and such simplifications or omissions cannot be used to limit the scope of the present invention.

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

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

[0008] In order to solve the above technical problems, the present invention provides the following technical solutions: an overflow-type microalgae photobioreactor based on efficient utilization of light energy, the reactor comprising a container assembly, a circulation assembly and a gas supply assembly, wherein the container assembly comprises an outer container and an inner container arranged in the inner cavity of the outer container; the circulation assembly is arranged between the outer container and the inner container, and comprises a circulation pipe, a circulation pump connected to the circulation pipe, and a nozzle group connected to the circulation pipe and extending into the inner container; the gas supply assembly has an output end extending into the inner container.

[0009] As a preferred solution of the overflow type microalgae photobioreactor based on efficient utilization of light energy described in the present 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 solution of the overflow type microalgae photobioreactor based on efficient utilization of light energy of the present invention, 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 solution of the overflow type microalgae photobioreactor based on efficient utilization of light energy described in the present invention, wherein: a guide plate is extended outwardly from the circumferential side wall 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 is not less than the liquid level of the microalgae cell suspension in the cavity.

[0012] As a preferred solution of the overflow type microalgae photobioreactor based on efficient utilization of light energy of the present invention, the input end of the circulation pipe is connected to the containing cavity, and the output end thereof is connected to the input interface of the nozzle group.

[0013] As a preferred solution of the overflow type microalgae photobioreactor based on efficient utilization of light energy described in the present invention, the nozzle group is arranged at the bottom area of ​​the inner container, and it also includes a plurality of groups of nozzles evenly distributed and connected to the input interface.

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

[0015] As a preferred solution of the overflow type microalgae photobioreactor based on efficient utilization of light energy of the present invention, wherein: the number of the aerators is the same as that of the nozzles and they correspond one to one, and the aerators are located directly above the corresponding nozzles.

[0016] As a preferred solution of the overflow type microalgae photobioreactor based on efficient utilization of light energy described in the present invention, wherein: a gas rich in carbon dioxide is introduced into the gas supply pipeline.

[0017] As a preferred solution of the overflow type microalgae photobioreactor based on efficient utilization of light energy of the present invention, the incident light is irradiated toward the microalgae cell suspension from directly above the outer container.

[0018] Beneficial effects of the present invention:

[0019] The present invention is an overflow type microalgae photobioreactor, which can reduce the adverse effect of uneven light energy distribution inside the reactor on the growth of microalgae cells through the innovation of the reactor structure, thereby improving the light receiving condition of the microalgae cells in the reactor and greatly increasing the yield of microalgae biomass and the fixation of CO2. BRIEF DESCRIPTION OF THE DRAWINGS

[0020] In order to more clearly illustrate the technical solutions of the embodiments of the present invention, the following briefly introduces the drawings required for describing the embodiments. Obviously, the drawings described below are only some embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without creative labor. Among them:

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

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

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

[0024] Figure 4 It is a schematic top view of an overflow type microalgae photobioreactor based on efficient utilization of light energy according to the present invention. DETAILED DESCRIPTION

[0025] In order to make the above-mentioned objects, features and advantages of the present invention more obvious and easy to understand, the specific implementation methods of the present invention are described in detail below in conjunction with the accompanying drawings.

[0026] In the following description, many specific details are set forth to facilitate a full understanding of the present invention, but the present invention may also be implemented in other ways different from those described herein, and those skilled in the art may make similar generalizations without violating the connotation of the present invention. Therefore, the present 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 term "in one embodiment" that appears in different places in this specification does not necessarily refer to the same embodiment, nor does it refer to a separate or selective embodiment that is mutually exclusive with other embodiments.

[0028] Secondly, the present invention is described in detail with reference to the schematic diagram. When describing the embodiments of the present invention in detail, for the sake of convenience, the cross-sectional diagrams showing the device structure will not be partially enlarged according to the general scale, and the schematic diagrams are only examples, which should not limit the scope of protection of the present invention. In addition, in actual production, the three-dimensional dimensions of length, width and depth should be included.

[0029] Example 1

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

[0031] Specifically, the container assembly 100 includes an outer container 101 and an inner container 102 disposed in the inner cavity of the outer container; wherein the outer container 101 and the inner container 102 may be disposed coaxially or coaxially, and may be an integral structure or a split structure, and there is no specific limitation on this. Similarly, there is no specific limitation on the radial cross-sectional shape of the inner and outer containers, and they may be circular, square, triangular, etc.; in this solution, 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, 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. And the liquid level of the microalgae cell suspension Y in the inner container 102 needs to 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 sprayed into the inner chamber 102 during operation is always equal to the flow rate of the microalgae cell suspension flowing to the outer chamber 101, that is, the liquid levels of the inner chamber 102 and the outer chamber 101 remain unchanged, it is only necessary to ensure that the liquid level of the inner chamber 102 just reaches the top of the inner chamber 102 and is higher than the liquid level of the cavity R before the reactor is operated, so as to ensure the normal operation of the overflow type microalgae photobioreactor. The suspensions in the two chambers are kept circulating through the circulation component 200.

[0033] For the inner container 102, a guide plate 102a is extended outwardly from the circumferential side wall of the top opening, and the height of the end of the guide plate 102a extending outward is lower than the height of the top opening of the inner container 102, and is not less than the liquid level of the microalgae cell suspension Y in the cavity R. Specifically, the guide plate 102a is an annular structure, extending outwardly from the circumferential side wall of the top opening of the inner container 102 by a certain width, and the height of the end extending outward is slightly lower, and the annular surface can be an inner concave surface type, a convex surface type, and a flat surface type; in this embodiment, a convex guide plate structure is used for display and explanation.

[0034] Here, the guide plate 102a is used to increase the flow area of ​​the suspension and reduce the thickness of the liquid layer of the suspension, so that the microalgae 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 toward the cavity R under the action of gravity; therefore, the annular width of the guide plate 102a can be appropriately increased, and the height of its lower end is not below the liquid surface of the suspension in the cavity R.

[0035] Furthermore, the circulation component 200 is arranged between the outer container 101 and the inner container 102, and includes a circulation pipe 201, a circulation pump 202 connected to the circulation pipe 201, and a nozzle group 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 the output end thereof is connected to the input interface 203a of the nozzle group 203.

[0036] The nozzle group 203 is disposed in the bottom area of ​​the inner container 102, and further includes a plurality of nozzles 203b that are evenly distributed and 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 set outside the container assembly 100 or inside the cavity R. The specific position can be set according to the actual reactor structure. The circulation pump 202 is used to provide power for liquid circulation; driven by the circulation pump 202, the microalgae cell suspension Y flowing to the outer chamber 101 will enter the inner chamber 102 again to form a circulation flow of the microalgae cell suspension. The circulation flow of the microalgae cell suspension can continuously flow the microalgae cell suspension in the bottom area of ​​the inner chamber 102 away from the light incident surface to the top of the inner chamber 102 close to the light incident surface, accelerate the circulation of microalgae cells between the light-sufficient area and the light-deficient area, so that more microalgae cells can fully absorb light energy in the light-sufficient area for photosynthesis, and provide the required energy for the growth of microalgae cells. In particular, it improves the light receiving condition of the microalgae cells originally in the bottom area of ​​the inner chamber 102. At the same time, during the circulation process, a thin liquid film formed by the microalgae cell suspension along the upper surface of the guide plate can effectively increase the contact area between the microalgae cells and the light, improve the utilization rate of light energy, and provide sufficient light for the growth of the microalgae cells.

[0038] The nozzle group 203 is distributed at the bottom of the inner container 102 or in an area close to the bottom. In order to ensure the smooth flow of the suspension, the nozzle group 203 has a plurality of nozzles 203b that are evenly distributed.

[0039] Furthermore, in order to ensure that the microalgae cell suspension Y in the inner chamber 102 flows upward uniformly and allows more microalgae cells to reach the light-sufficient area, the present solution installs a valve F at the lower end of each nozzle 203 b, and the valve F of each nozzle 203 b can be independently controlled to thereby adjust the flow rate of the microalgae cell suspension sprayed into the inner chamber 102 by each nozzle 203 b.

[0040] The CO2 required for photosynthesis of the microalgae cells is transported to the inner container 102 through the gas supply component 300. Specifically, the gas supply component 300 includes a gas supply pipeline 301, a gas supply branch pipe 302 connected to the output end of the gas supply pipeline 301, and an aerator 303 arranged at the output end of the gas supply branch pipe 302; wherein, a gas rich in carbon dioxide is passed into the gas supply pipeline 301. The gas supply pipeline 301 is used to transport external CO2 to the gas supply branch pipe 302 and discharge it through the aerator 303. The aerator 303 is used to generate a large number of bubbles rich in CO2 to be discharged into the microalgae cell suspension, and dissolved in the microalgae cell suspension Y to provide raw materials for the photosynthesis of the microalgae cells.

[0041] Furthermore, the number of aerators 303 and nozzles 203b is the same and corresponds one to one, and the aerator 303 is located directly above the corresponding nozzle 203b and close to the nozzle 203b; therefore, the microalgae cell suspension Y sprayed into the inner chamber 102 by the nozzle 203b can flush and break a large number of CO2-rich bubbles under the action of flow, increase the gas-liquid contact area, promote the dissolution of CO2 in the microalgae cell suspension Y, and provide sufficient inorganic carbon for the photosynthetic carbon fixation growth of the microalgae cells in the reactor.

[0042] The incident light G is selected to irradiate the microalgae cell suspension Y from directly above the outer container 101 .

[0043] Example 2

[0044] This is the second embodiment of the present invention, which is an example of using the reactor in Example 1:

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

[0046] In this specific embodiment, the microalgae cell suspension Y is driven by the circulation pump 202 to flow 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, pushing 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 closer to the incident light G, so that the microalgae cells located in the light-deficient area can enter the light-sufficient area, and 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, and then continues to flow to the outer container 101 under the action of gravity, completing a cycle of the microalgae cell suspension and entering the next cycle.

[0047] The CO2 required for photosynthesis of the microalgae cells is transported to the aerator 303 through the gas supply pipe 301, and a large number of bubbles rich in CO2 are generated by the aerator 303 and enter the microalgae cell suspension Y. Under the flushing effect of the nozzle 203b spraying the microalgae cell suspension into the inner container 102, a large number of bubbles rich in CO2 are broken, increasing the gas-liquid contact area, promoting the dissolution of CO2 in the microalgae cell suspension Y, and improving the efficiency of photosynthesis of the microalgae cells. With the coordinated cooperation of various components, the efficient utilization of light energy of the overflow microalgae photobioreactor is achieved.

[0048] It should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention rather than to limit it. Although the present invention has been described in detail with reference to the preferred embodiments, those skilled in the art should understand that the technical solutions of the present invention may be modified or replaced by equivalents without departing from the spirit and scope of the technical solutions of the present invention, which should all be included in the scope of the claims of the present invention.

Claims

1. An overflow type microalgae photobioreactor based on efficient utilization of light energy, characterized by: include, A container assembly (100) comprising an outer container (101) and an inner container (102) disposed in an inner cavity of the outer container; a circulation assembly (200), arranged between the outer container (101) and the inner container (102), comprising a circulation pipe (201), a circulation pump (202) connected to the circulation pipe (201), and a nozzle group (203) connected to the circulation pipe (201) and extending into the inner container (102); and, The gas supply component (300) has an output end extending into the inner container (102).

2. The overflow-type microalgae photobioreactor based on efficient utilization of light energy according to claim 1, characterized in that: 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 a microalgae cell suspension (Y).

3. The overflow-type microalgae photobioreactor based on efficient utilization of light energy according to claim 2, characterized in that: The liquid level of the microalgae cell suspension (Y) in the inner container (102) is greater than the liquid level of the microalgae cell suspension (Y) in the chamber (R).

4. The overflow-type microalgae photobioreactor based on efficient utilization of light energy according to claim 3, characterized in that: A guide plate (102a) is extended outwardly from the circumferential side wall of the top opening of the inner container (102), and the height of one end of the guide plate (102a) extending outwardly is lower than the height of the top opening of the inner container (102) and is not less than the liquid level of the microalgae cell suspension (Y) in the cavity (R).

5. The overflow-type microalgae photobioreactor based on efficient utilization of light energy according to claim 4, characterized in that: The input end of the circulation pipe (201) is connected to the chamber (R), and the output end thereof is connected to the input interface (203a) of the nozzle group (203).

6. The overflow-type microalgae photobioreactor based on efficient utilization of light energy according to claim 5, characterized in that: The nozzle group (203) is arranged at the bottom area of ​​the inner container (102), and further comprises a plurality of nozzles (203b) that are evenly distributed and connected to the input interface (203a).

7. The overflow-type microalgae photobioreactor based on efficient utilization of light energy according to claim 6, characterized in that: The air supply assembly (300) comprises an air supply pipeline (301), an air supply branch pipe (302) connected to the output end of the air supply pipeline (301), and an aerator (303) arranged at the output end of the air supply branch pipe (302).

8. The overflow-type microalgae photobioreactor based on efficient utilization of light energy according to claim 7, characterized in that: The number of the aerators (303) and the nozzles (203b) are the same and correspond one to one, and the aerators (303) are located directly above the corresponding nozzles (203b).

9. The overflow-type microalgae photobioreactor based on efficient utilization of light energy according to claim 8, characterized in that: The gas supply pipeline (301) is supplied with gas rich in carbon dioxide.

10. The overflow-type microalgae photobioreactor based on efficient utilization of light energy according to claim 9, characterized in that: The incident light (G) is irradiated toward the microalgae cell suspension (Y) from directly above the outer container (101).

Images