CN115350578A

CN115350578A - Algae carbon trapping device and using method thereof

Info

Publication number: CN115350578A
Application number: CN202211018840.1A
Authority: CN
Inventors: 颜欣; 万玉山
Original assignee: Changzhou University
Current assignee: Changzhou University
Priority date: 2022-08-24
Filing date: 2022-08-24
Publication date: 2022-11-18

Abstract

The invention discloses an algae carbon capturing device and a using method thereof, and relates to the technical field of carbon dioxide capturing and utilization. The invention obtains the carbon dioxide gas source with specific concentration, and carries out photosynthesis in the closed algae biological reaction unit and the plant culture unit in sequence, so that the carbon dioxide after carbon capture is fixed by algae and plants, during the process, the carbon dioxide meeting the conditions is monitored to carry out the next step of photosynthesis or be discharged, the carbon dioxide not meeting the conditions is re-concentrated or returns to the previous step to continue the photosynthesis, and the two kinds of photosynthesis complement each other to form synergistic action, thereby greatly improving the biological carbon fixation amount and the carbon fixation efficiency.

Description

Algae carbon trapping device and using method thereof

Technical Field

The invention relates to the technical field of carbon dioxide capture and utilization, in particular to an algae carbon capture device and a use method thereof.

Background

With the use of a large amount of fossil energy, the emission of greenhouse gases is increasing year by year, resulting in many environmental problems such as climate change. CO, the most predominant greenhouse gas ₂ Effective capture, sequestration and reuse of the carbon are one of the direct means for realizing carbon emission reduction. Among the carbon capture technologies, the chemical absorption method is the most common, but has problems of high energy consumption, corrosion of equipment, and the like. In recent years, the microalgae carbon sequestration method has attracted people's attention due to its environmental friendliness, but CO is used ₂ The solubility is low, and the carbon fixation efficiency of the microalgae is not expected.

Chinese patent "carbon fixation method based on biology" (application number: 202111139061.2) discloses a carbon capture-algae/plant culture carbon fixation system. The carbon capture-algae/plant culture carbon sequestration system comprises: a carbon capture device, an algae bioreaction unit and a plant culture unit. The patent combines the existing green house to reform transform, both can improve the output of crops, can consolidate carbon again, kills two birds with one stone, on the basis of calculating carbon trading price, can improve whole economy greatly.

Chinese patent "carbon capture-algae/plant culture carbon fixation system" (application No. 202111124583.5) discloses a carbon capture-algae/plant culture carbon fixation system. The carbon capture-algae/plant culture carbon sequestration system comprises: a carbon capture device, an algae bioreaction unit and a plant culture unit. This patent can utilize the carbon dioxide of different concentrations through the mode that microalgal culture and plant planting combined together by gradient to make one-level photosynthesis and second grade photosynthesis all go on under the carbon dioxide concentration of comparatively adapting to, thereby improved the utilization ratio of carbon dioxide by a wide margin, can also improve biological solid carbon volume simultaneously. However, the above patents are complicated in operation and the device is inefficient.

Disclosure of Invention

The technical problem to be solved by the invention is as follows: in order to overcome the defects of complex operation, low carbon fixing efficiency and the like in the patent, the invention provides the algae carbon collecting device with simple operation and less investment and the use method thereof, which are suitable for pollution treatment with higher carbon content.

In order to achieve the purpose, the invention provides an algae carbon capture device, which comprises an initial gas source, a carbon capture system, a pressure control unit, an algae biological reaction unit, a primary tail gas outlet, a plant culture unit, a secondary tail gas outlet and a first exhaust port, wherein the initial gas source, the carbon capture system, the pressure control unit, the algae biological reaction unit, the primary tail gas outlet, the plant culture unit, the secondary tail gas outlet and the first exhaust port are sequentially communicated;

a first pipeline is arranged between the first-stage tail gas outlet and the plant culture unit, a first valve is arranged on the first pipeline, a second pipeline communicated with the algae reaction unit is arranged on the first pipeline between the first valve and the first-stage tail gas outlet, and a first return valve is arranged on the second pipeline; a seventh pipeline is further arranged on the first pipeline between the first valve and the primary tail gas outlet, the tail end of the seventh pipeline is connected with a second exhaust port, and a third valve is arranged between the seventh pipeline and the second exhaust port;

a third pipeline is arranged between the secondary tail gas outlet and the first exhaust port, a second valve is arranged on the third pipeline, a fourth pipeline communicated with the algae bioreaction unit is arranged on the third pipeline between the second valve and the secondary tail gas outlet, and a second backflow valve is arranged on the fourth pipeline;

the algae biological reaction unit is internally sealed for primary photosynthesis, and the plant culture unit is internally sealed for secondary photosynthesis.

Preferably, a first flow sensor is arranged at the first-stage tail gas outlet, and a second flow sensor is arranged at the second-stage tail gas outlet.

Preferably, when the first flow sensor detects that the concentration of the carbon dioxide is less than 400ppm, the first valve and the first reflux valve are closed, and the third valve is opened; when the first flow sensor monitors that the concentration of the carbon dioxide is 400-800 ppm, the first valve is opened, and the first reflux valve and the third valve are closed; when the first flow sensor monitors that the concentration of the carbon dioxide is 800-1200 ppm, the first valve and the third valve are closed, and the first return valve is opened.

Preferably, when the second flow sensor monitors that the concentration of the carbon dioxide is less than 400ppm, the second valve is opened, and the second return valve is closed; when the second flow sensor detects that the concentration of the carbon dioxide is more than 400ppm, the second valve is closed, and the second return valve is opened.

Preferably, a sixth pipeline communicated with the initial gas source is further arranged on a third pipeline between the second valve and the secondary tail gas outlet, a fourth backflow valve is arranged on the sixth pipeline, when the second flow sensor monitors that the concentration of carbon dioxide is greater than 400ppm, the second valve and the second backflow valve are closed, the fourth backflow valve is opened, carbon dioxide in the secondary tail gas is concentrated, when the second flow sensor monitors that the concentration of carbon dioxide is less than 400ppm, the second backflow valve and the fourth backflow valve are closed, and the second valve is opened.

Preferably, a fifth pipeline communicated with the initial gas source is further arranged on the first pipeline between the first valve and the first-stage tail gas outlet, a third reflux valve is arranged on the fifth pipeline, when the first flow sensor monitors that the concentration of carbon dioxide is more than 400ppm, the first valve, the third valve and the first reflux valve are closed, and the third reflux valve is opened to concentrate the carbon dioxide in the first-stage tail gas; when the first flow sensor monitors that the concentration of the carbon dioxide is less than 400ppm, the first valve, the third reflux valve and the first reflux valve are closed, and the third valve is opened.

Preferably, the carbon capture of the carbon capture system comprises the steps of: (1) Extracting and separating from plant ash to obtain saturated potassium carbonate solution; (2) Introducing the initial gas source into the saturated potassium carbonate solution to absorb carbon dioxide to obtain a first solution; (3) Heating the first solution to release carbon dioxide gas and collecting.

The invention also provides a use method of the carbon capture device, which comprises the following steps:

s1a: a carbon dioxide gas source in an initial gas source is obtained through a carbon capture system, and the concentration of carbon dioxide in the carbon dioxide gas source is controlled to be less than or equal to 1400ppm through a pressure control unit;

s2a: introducing a carbon dioxide gas source into the closed algae biological reaction unit to perform primary photosynthesis, and discharging primary tail gas through a primary tail gas outlet;

s3a: if the concentration of carbon dioxide in the first-stage tail gas is 800-1200 ppm, introducing the first-stage tail gas into the algae biological reaction unit again for first-stage photosynthesis; if the concentration of carbon dioxide in the primary tail gas is 400-800 ppm, introducing the primary tail gas into a closed plant culture unit for secondary photosynthesis, and discharging the secondary tail gas through a secondary tail gas outlet;

s4a: if the concentration of carbon dioxide in the secondary tail gas is more than or equal to 400ppm, introducing the secondary tail gas into the algae biological reaction unit again for primary photosynthesis; and if the concentration of carbon dioxide in the secondary tail gas is less than 400ppm, emptying the secondary tail gas through the first exhaust port.

The invention also provides another method of using a carbon capture device, comprising the steps of:

s1b: a carbon dioxide gas source in the initial gas source is obtained through a carbon capture system, and the concentration of carbon dioxide in the carbon dioxide gas source is controlled to be less than or equal to 1400ppm through a pressure control unit;

s2b: introducing a carbon dioxide gas source into the closed algae biological reaction unit to perform primary photosynthesis, and discharging primary tail gas through a primary tail gas outlet;

s3b: if the concentration of carbon dioxide in the first-stage tail gas is more than or equal to 400ppm, concentrating the first-stage tail gas and introducing the initial gas source again for carbon capture; and if the concentration of carbon dioxide in the first-stage tail gas is less than 400ppm, emptying the first-stage tail gas through a second exhaust port.

s1c: a carbon dioxide gas source in the initial gas source is obtained through a carbon capture system, and the concentration of carbon dioxide in the carbon dioxide gas source is controlled to be less than or equal to 1400ppm through a pressure control unit;

s2c: introducing a carbon dioxide gas source into the closed algae biological reaction unit to perform primary photosynthesis, and discharging primary tail gas through a primary tail gas outlet;

s3c: if the concentration of carbon dioxide in the first-stage tail gas is 800-1200 ppm, introducing the first-stage tail gas into the algae biological reaction unit again for first-stage photosynthesis; if the concentration of carbon dioxide in the primary tail gas is 400-800 ppm, introducing the primary tail gas into a closed plant culture unit for secondary photosynthesis, and discharging the secondary tail gas through a secondary tail gas outlet;

s4c: if the concentration of carbon dioxide in the secondary tail gas is more than or equal to 400ppm, concentrating the secondary tail gas and introducing the initial gas source again for carbon capture; and if the concentration of carbon dioxide in the secondary tail gas is less than 400ppm, emptying the secondary tail gas through the first exhaust port.

Compared with the prior art, the invention has the advantages that:

the invention can effectively improve the carbon fixing capacity and the treatment efficiency in the prior art, can use local materials in the agricultural greenhouse, does not depend on traditional equipment, saves the storage cost and the transmission cost, and increases the economical efficiency of the system;

by applying the technical scheme of the invention, the carbon dioxide gas source with specific concentration is obtained through the carbon capture system and the pressure control unit. Then the carbon dioxide carbon source after carbon capture is fixed by the algae and plant culture units, and simultaneously, the carbon dioxide flow discharged to each stage is accurately controlled by monitoring tail gas, so that the carbon dioxide meeting the conditions is subjected to next-step photosynthesis or discharged, the carbon dioxide not meeting the conditions is re-concentrated or returns to the previous stage to continue photosynthesis, and the two photosynthesis reactions supplement each other to form a synergistic effect, thereby greatly improving the biological carbon fixation amount and the carbon fixation efficiency.

Drawings

The accompanying drawings, which are incorporated in and constitute a part of this specification, illustrate embodiments consistent with the invention and together with the description, serve to explain the principles of the invention, in which:

FIG. 1 is a flow chart of the operation of an algal carbon capture device according to the present invention;

fig. 2 is a schematic structural diagram of a return valve piping system designed by the invention.

Reference numerals are as follows:

1. a carbon capture system; 2. a pressure control unit; 3. an algae bioreaction unit; 4. a first valve; 5. a second valve; 6. a plant cultivation unit; 7. a first exhaust port; 8. an initial gas source; 9. a first-stage tail gas outlet; 10. a secondary tail gas outlet; 11. a second conduit; 12. a fourth conduit; 13. a fifth pipeline; 14. a sixth pipeline; 15. a first flow sensor; 16. a third reflux valve; 17. a first reflux valve; 18. a first pipe; 19. a second flow sensor; 20. a fourth reflux valve; 21. a second reflux valve; 22. a third pipeline; 23. a second exhaust port; 24. a third valve; 25. a seventh pipe; 26. an air inlet; 27. an inlet guide vane; 28. a first stage compression device; 29. a secondary compression device; 30. a first flow monitor; 31. a first air outlet; 32. a return valve system.

Detailed Description

The following disclosure provides many different embodiments or examples for implementing different features of the invention. To simplify the disclosure of the present invention, the components and arrangements of specific examples are described below. Of course, they are merely examples and are not intended to limit the present invention. Furthermore, the present invention may repeat reference numerals and/or letters in the various examples, such repetition is for the purpose of simplicity and clarity and does not in itself dictate a relationship between the various embodiments and/or configurations discussed.

As described in the background, the existing biological carbon fixation method has the problem that the carbon fixation efficiency is not high. In order to solve the technical problem, the present application provides a carbon sequestration method based on biology, comprising: obtaining a carbon dioxide gas source by adopting a carbon capture system 1 through an initial gas source 8, enabling the concentration of the carbon dioxide to be less than or equal to 1400ppm through a pressure control unit 2, enabling the carbon dioxide meeting the conditions to enter an algae biological reaction unit 3 through a pipeline, enabling algae to perform primary photosynthesis in a closed space, discharging primary tail gas through a primary tail gas outlet 9, enabling the carbon dioxide in the algae biological reaction unit 3 to enter a plant culture unit 6 through a first pipeline 18, enabling plants to perform secondary photosynthesis in the closed space, and discharging secondary tail gas through a secondary tail gas outlet 10; wherein most of the carbon dioxide generated by the first-stage photosynthesis is from a carbon dioxide gas source collected after carbon capture, a small part of the carbon dioxide is from the backflow carbon dioxide generated by the plant culture unit 6, and the carbon dioxide generated by the second-stage photosynthesis is from a carbon dioxide gas source generated after the action of the algae biological reaction unit 3.

When the two kinds of photosynthesis are carried out alternately, the initial carbon dioxide gas source 8 can be used for providing most of carbon dioxide required by the first-stage photosynthesis of the algae biological reaction unit 3, the high photosynthesis efficiency of the algae is used for carrying out high-efficiency carbon fixation, then the carbon dioxide treated by the first-stage photosynthesis is used for providing carbon dioxide required by the second-stage photosynthesis of the plant culture unit 6, crops are used for further carbon fixation, and the utilization rate of the carbon dioxide is more efficient by the grading carbon fixation mode.

In this embodiment, in order to better control the concentration of carbon dioxide in the primary tail gas and the secondary tail gas, the concentration of carbon dioxide in the primary tail gas can be monitored by using the first carbon dioxide flow sensor 15, and the concentration of carbon dioxide in the secondary tail gas can be monitored by using the second flow sensor 19.

In this embodiment, the operation mechanism of the apparatus includes, but is not limited to, the following:

1. the first mode is as follows:

when the concentration of carbon dioxide in the first-stage tail gas after the first-stage photosynthesis in the algae biological reaction unit 3 is 800ppm to 1200ppm, closing the third valve 24, the first valve 4 and the third backflow valve 16, and connecting the first-stage tail gas through the second pipeline 11 and the first backflow valve 17 to be re-introduced into the algae biological reaction unit 3 for the first-stage photosynthesis; when the concentration of carbon dioxide in the first-stage tail gas after the first-stage photosynthesis in the algae biological reaction unit 3 is 400 ppm-800 ppm, closing the first reflux valve 17, the third reflux valve 24 and the third reflux valve 16, and linking the first-stage tail gas through the first pipeline 18 and the first valve 4 to the plant reaction unit 6 for the second-stage photosynthesis; by monitoring the concentration of the carbon dioxide in the first-stage tail gas, the treatment efficiency of the first-stage photosynthesis of the algae is detected in real time, and the carbon dioxide with the specified concentration can be better conveyed to the plant culture unit 6.

When the concentration of carbon dioxide in the secondary tail gas is more than or equal to 400ppm after the plant cultivation unit 6 performs secondary photosynthesis, the second valve 5 and the fourth return valve 20 are closed, the secondary tail gas is linked through the fourth pipeline 12 and the second return valve 21 and is introduced into the algae bioreaction unit 3 again, so that the secondary tail gas participates in the primary photosynthesis again, when the concentration of carbon dioxide in the secondary tail gas is less than 400ppm, the fourth return valve 20 and the second return valve 21 are closed, and the secondary tail gas is introduced into the first exhaust port 7 through the third pipeline 22 and the second valve 5 and is exhausted. The method can realize the grading fixation of the carbon dioxide, thereby greatly improving the biological carbon fixation amount and the carbon fixation efficiency.

2. The second mode is as follows:

when the concentration of carbon dioxide in the first-stage tail gas outlet 9 is more than or equal to 400ppm, concentrating the first-stage tail gas to obtain carbon dioxide concentrated gas, re-linking the carbon dioxide concentrated gas of the first-stage tail gas to the initial gas source 8 through the fifth pipeline 13 and the third reflux valve 16 to be used as a part of the initial gas source 8 for preparing the carbon dioxide gas source, and re-linking the carbon dioxide concentrated gas to the algae biological reaction unit 3 through the second pipeline 11 and the first reflux valve 17 to be used as a part of the carbon dioxide source for first-stage photosynthesis; when the concentration of carbon dioxide in the first-stage tail gas outlet 9 is less than 400ppm, the first-stage tail gas can be directly introduced into the second exhaust port 23 through the seventh pipeline 25 and the third valve 24, and the first-stage tail gas is exhausted to achieve the purpose of treating the over-high concentration carbon dioxide.

3. The third mode is as follows:

when the concentration of carbon dioxide in the first-stage tail gas after the first-stage photosynthesis in the algae biological reaction unit 3 is 800ppm to 1200ppm, closing the third valve 24, the first valve 4 and the third backflow valve 16, and connecting the first-stage tail gas through the second pipeline 11 and the first backflow valve 17 to be re-introduced into the algae biological reaction unit 3 for the first-stage photosynthesis; when the concentration of carbon dioxide in the first-stage tail gas after the first-stage photosynthesis in the algae biological reaction unit 3 is 400 ppm-800 ppm, closing the first reflux valve 17, the third reflux valve 24 and the third reflux valve 16, and linking the first-stage tail gas through the first pipeline 18 and the first valve 4 to the plant reaction unit 6 for the second-stage photosynthesis; when the concentration of carbon dioxide in the secondary tail gas outlet 10 after the secondary photosynthesis of the plant is more than or equal to 400ppm, concentrating the secondary tail gas, similarly reconnecting the carbon dioxide concentrated gas of the secondary tail gas to the initial gas source 8 through the sixth pipeline 14 and the fourth return valve 20 to be used as part of the initial gas source 8 for preparing the carbon dioxide gas source, and reconnecting the carbon dioxide concentrated gas to the algae bioreactor unit 3 through the fourth pipeline 12 and the second return valve 21 to be used as part of the carbon dioxide source for the primary photosynthesis; when the concentration of the carbon dioxide in the secondary tail gas outlet 10 is less than 400ppm, the secondary tail gas is introduced into the first exhaust port 7 through the third pipeline 22 and the second valve 5, and the secondary tail gas is exhausted to achieve the purpose of treating the over-high concentration carbon dioxide.

The method employed in the above-described concentration process may be a method commonly used in the art, including, but not limited to, concentration of carbon dioxide using a reciprocating compressor and an adsorption-desorption method.

In this embodiment, fig. 2 is a schematic diagram of a return valve piping system 32 designed according to the present invention between the primary tail gas outlet 9 and the plant cultivation unit 6, and used when it is desired to concentrate carbon dioxide. For example, in the second operation mode, when the carbon dioxide in the primary tail gas is input to the plant reaction unit 6 in the first pipeline 18, when the carbon dioxide (the concentration is greater than or equal to 400 ppm) in the primary tail gas, the reflux valve pipeline system 32 is opened to concentrate, the carbon dioxide firstly enters the inlet guide vane 27 at the air inlet 26, and the inlet guide vane 27 is provided with a pressure gauge to monitor the concentration of the input carbon dioxide in real time and ensure safety. Then the carbon dioxide enters a first-stage compression device, and is subjected to first compression work through a gas compressor, and then is subjected to second compression through a second-stage compression device. The whole compression process is divided into two steps in order to prevent the machine from being damaged due to excessive consumption of power of the machine caused by the disposable compressed gas and to better achieve the purpose of conveniently measuring the gas concentration in the subsequent process of compressing the gas. The carbon dioxide is then passed through a third return valve 16 via a first gas outlet 31 connected to the secondary compression device into a fifth conduit 13, where it is returned to the original source 8 for continued carbon capture. If the concentration of the carbon dioxide in the first-stage tail gas reaches the standard (the concentration is less than 400 ppm), the reflux valve pipeline system 32 is not opened for concentration, and the carbon dioxide is directly released through the seventh pipeline 25 and the second exhaust port 23. Similarly, the return valve piping system 32 is also provided between the secondary exhaust gas outlet 10 and the first exhaust port 7, for example, in a third operation mode, if the carbon dioxide in the secondary exhaust gas (concentration ≥ 400 ppm), the return valve piping system 32 is opened for concentration, the carbon dioxide in the secondary exhaust gas is concentrated and returned to the initial gas source 8 through the fourth return valve 20 and the sixth piping 14, if the carbon dioxide in the secondary exhaust gas (concentration < 400 ppm), the carbon dioxide is directly discharged through the third piping 22 and the first exhaust port 7.

In this embodiment, the carbon capture process includes capturing the initial gas source 8 from a mixture of raw gases including carbon dioxide, the mixture further including at least one of a primary tail gas and a secondary tail gas. The full capture and utilization of the carbon dioxide are realized. The carbon dioxide-containing primary gas source 8 can be any carbon dioxide-containing gas or carbon dioxide-enriched gas.

In this embodiment, the apparatus for primary photosynthesis of algae includes an algae incubator for cultivating algae and an algae separator for drying and separating the algae transferred from the algae incubator, wherein the algae incubator includes: a plurality of algae cultivation tanks connected in series and in parallel to each other to cultivate algae received therein, and a carbon dioxide supply unit connected to one side of the algae cultivation tanks through a carbon dioxide supply pipe to supply algae received in the algae cultivation tanks. Wherein the algae cultivation tank includes a plurality of connection pipes connecting the algae cultivation tank in series or in parallel, and the nutrient supply unit is connected to one side of the algae cultivation tank through the nutrient supply pipe.

In this embodiment, the algae are natural algae or synthetic algae in the primary photosynthesis. The algae may be selected from Spirulina, chaetoceros, chlorella, oscillatoria, etc. The synthetic algae adopted by the invention has the following characteristics: (1) The algae has fast growth speed and short growth period, and can be cultured in a large scale; (2) The algae has strong carbon sequestration capacity and low cost and energy consumption; (3) The algae can absorb nitrogen, phosphorus, heavy metals and the like while fixing carbon during menstruation, and has good purification effect on the environment.

In this embodiment, a pressure stabilizing air exhausting device is further provided, which comprises a primary pressure stabilizing air exhausting device and a secondary pressure stabilizing air exhausting device. The algae biological reaction unit 3 is provided with a first-stage carbon dioxide inlet and a first-stage pressure-stabilizing exhaust device which are diagonally arranged, and the plant cultivation unit 6 is provided with a second-stage carbon dioxide inlet and a second-stage pressure-stabilizing exhaust device which are diagonally arranged. The first-stage pressure-stabilizing air exhausting device is provided with a first flow sensor 15, and the second-stage pressure-stabilizing air exhausting device is provided with a second flow sensor 19. The first-stage carbon dioxide inlet is used for introducing carbon dioxide which is accessed by the initial gas source 8 and passes through the carbon capture system 1, and the second-stage carbon dioxide inlet is used for introducing carbon dioxide in the first-stage tail gas after the treatment of the algae biological reaction unit 3. The first flow sensor 15 of the primary pressure-stabilizing air-exhausting device and the second flow sensor 19 of the secondary pressure-stabilizing air-exhausting device are used for measuring the concentration of the carbon dioxide passing through the first flow sensor and the second flow sensor. When the gas passes through the pressure-stabilizing exhaust device, the carbon dioxide flow sensor detects the concentration of carbon dioxide in the gas passing through the pressure-stabilizing exhaust device, and when the concentration of carbon dioxide is more than or equal to 400ppm, the carbon dioxide can be collected and recovered, for example, the first-stage tail gas or the second-stage tail gas is concentrated to obtain carbon dioxide concentrated gas, and the carbon dioxide concentrated gas is used as part of raw material gas for preparing an initial gas source; when the concentration of carbon dioxide is less than 400ppm, the air is exhausted by using a pressure-stabilizing exhaust device. When a second air outlet of the primary pressure-stabilizing air exhaust device of the algae bioreaction unit 3 is connected with a secondary carbon dioxide inlet of the plant cultivation unit 6, the primary pressure-stabilizing air exhaust device is arranged at the top end of the algae bioreaction unit 3 and used for exhausting primary tail gas, and meanwhile, a primary carbon dioxide inlet is arranged at the diagonal position of the primary pressure-stabilizing air exhaust device and used as an input port of a carbon dioxide gas source; the end of the top of the plant cultivation unit 6 is provided with a secondary pressure-stabilizing exhaust device, and a secondary carbon dioxide inlet is arranged at the diagonal position of the plant cultivation unit, and the secondary carbon dioxide inlet is connected with a second air outlet of the primary pressure-stabilizing exhaust device of the algae biological reaction unit 3 to be used as a primary tail gas outlet 9. The first flow sensor 15 in the primary pressure-stabilizing exhaust device can monitor the concentration of carbon dioxide in the primary tail gas, and when the concentration of carbon dioxide in the primary tail gas is 400-800 ppm, an air outlet of the primary pressure-stabilizing exhaust device is opened to enable the primary tail gas to enter the plant culture unit 6 through the secondary carbon dioxide inlet to participate in secondary photosynthesis; when the concentration of carbon dioxide in the first-stage tail gas is 800ppm to 1200ppm, the air outlet of the first-stage pressure-stabilizing exhaust device is closed, so that the first-stage tail gas returns to the algae biological reaction unit 3 again through the first return valve 17 and the second pipeline 11 to participate in the first-stage photosynthesis again. When the secondary tail gas passes through the secondary pressure-stabilizing exhaust device, the second flow sensor 19 detects the concentration of carbon dioxide in the secondary tail gas, when the concentration of carbon dioxide is more than or equal to 400ppm, the part of carbon dioxide needs to be collected and recovered, the secondary tail gas is concentrated to obtain carbon dioxide concentrated gas, and the carbon dioxide concentrated gas is used as at least part of raw material gas for preparing a carbon dioxide gas source, or the carbon dioxide concentrated gas is used as at least part of carbon dioxide source for primary photosynthesis and returns to the algae bioreaction unit 3. When the concentration of carbon dioxide is less than 400ppm, the air is exhausted by using a secondary pressure-stabilizing exhaust device.

The intensity of the natural light source is easily influenced by climate, so that the illumination intensity is not easy to control, the natural light source and the artificial light source can be combined, and the intensity change of the natural light source can be compensated through the artificial light source, so that the carbon fixation effect of the whole process is ensured, and the cleanness and the economy of the whole process can be improved. The artificial light source may be powered by clean energy sources including, but not limited to, energy sources derived from photovoltaic power generation, wind power generation, geothermal power generation, biomass power generation, or hydro power generation. When a natural light source is used, a photovoltaic device may be disposed on the top of the algae bioreaction unit 3 and the plant cultivation unit 6 or on the upper portion of the sunny side of the algae bioreaction unit 3 and the plant cultivation unit 6 to ensure that algae and crops can be maximally absorbed to the natural light source.

In this embodiment, the carbon capture process in the biological carbon sequestration method may be performed by a carbon capture method commonly used in the art, and the commonly used carbon dioxide capture technologies mainly include a solvent absorption technology and a solid adsorbent technology. The amine solvent absorption technology is a commonly used carbon dioxide capture technology and mainly comprises the following steps: traditional amine absorption process, hindered amine absorption process, and the like. However, the conventional amine solvent absorption trapping technology has obvious disadvantages, such as: large amounts of solvents are required, amines are corrosive, easily degradable, etc. Thus, another carbon capture method may also be used in this embodiment, the steps comprising: (1) Extracting plant ash from various plant shells, wherein the plant ash contains soluble salts such as potassium carbonate, potassium sulfate, potassium chloride and the like, adding water, and separating by a precipitation and filtration method to obtain a saturated potassium carbonate solution; (2) Blowing the gas to be treated into a saturated potassium carbonate solution, wherein the solution can absorb carbon dioxide to generate potassium bicarbonate; (3) Heating the solution to decompose carbon dioxide, releasing carbon dioxide gas and collecting. The carbon capture method is low in cost, natural and pollution-free, and the waste heat in the heating process in the step (3) can be used for maintaining a constant temperature suitable for the growth of the plant microalgae in a closed space in winter.

In this embodiment, in order to further improve the whole process flow, an intelligent device may be used to accurately control the temperature, light irradiation, flow rate, etc. of the whole algal carbon capture device.

Other embodiments of the invention will be apparent to those skilled in the art from consideration of the specification and practice of the invention disclosed herein. This invention is intended to cover any variations, uses, or adaptations of the invention following, in general, the principles of the invention and including such departures from the present disclosure as come within known or customary practice within the art to which the invention pertains. It is intended that the specification and examples be considered as exemplary only, with a true scope and spirit of the invention being indicated by the following claims.

It will be understood that the invention is not limited to the precise arrangements described above and shown in the drawings and that various modifications and changes may be made without departing from the scope thereof. The scope of the invention is limited only by the appended claims.

Claims

1. The algae carbon capture device is characterized by comprising an initial gas source, a carbon capture system, a pressure control unit, an algae biological reaction unit, a primary tail gas outlet, a plant culture unit, a secondary tail gas outlet and a first exhaust port which are sequentially communicated;

a first pipeline is arranged between the primary tail gas outlet and the plant culture unit, a first valve is arranged on the first pipeline, a second pipeline communicated with the algae reaction unit is arranged on the first pipeline between the first valve and the primary tail gas outlet, and a first return valve is arranged on the second pipeline; a seventh pipeline is further arranged on the first pipeline between the first valve and the primary tail gas outlet, a second exhaust port is connected to the tail end of the seventh pipeline, and a third valve is arranged between the seventh pipeline and the second exhaust port;

2. The apparatus according to claim 1, wherein a first flow sensor is disposed at the primary exhaust outlet, and a second flow sensor is disposed at the secondary exhaust outlet.

3. The algal carbon capture device of claim 2 wherein said first valve and said first return valve are closed and said third valve is opened when said first flow sensor detects a carbon dioxide concentration of < 400ppm; when the first flow sensor monitors that the concentration of the carbon dioxide is 400-800 ppm, the first valve is opened, and the first return valve and the third valve are closed; when the first flow sensor monitors that the concentration of the carbon dioxide is 800-1200 ppm, the first valve and the third valve are closed, and the first return valve is opened.

4. The algal carbon capture device of claim 3 wherein said second valve is open and said second return valve is closed when said second flow sensor detects a carbon dioxide concentration of < 400ppm; when the second flow sensor detects that the concentration of the carbon dioxide is more than 400ppm, the second valve is closed, and the second return valve is opened.

5. The device as claimed in claim 3, wherein a sixth pipeline is further disposed in the third pipeline between the second valve and the secondary exhaust outlet, the sixth pipeline is provided with a fourth reflux valve, a reflux valve pipeline system is disposed between the second flow sensor and the fourth reflux valve, when the second flow sensor detects that the concentration of carbon dioxide is greater than 400ppm, the second valve and the second reflux valve are closed, the fourth reflux valve and the reflux valve pipeline system are opened, carbon dioxide in the secondary exhaust is concentrated, when the second flow sensor detects that the concentration of carbon dioxide is less than 400ppm, the second reflux valve and the fourth reflux valve are closed, and the second valve is opened.

6. The algal carbon capture device of claim 2 wherein a fifth pipeline is provided in the first pipeline between the first valve and the primary exhaust outlet and in communication with the initial gas source, wherein a third return valve is provided in the fifth pipeline, wherein the return valve pipeline system is provided between the first flow sensor and the third return valve, wherein when the first flow sensor detects a carbon dioxide concentration of greater than 400ppm, the first valve, the third valve and the first return valve are closed, and the third return valve and the return valve pipeline system are opened to concentrate carbon dioxide in the primary exhaust; when the first flow sensor monitors that the concentration of carbon dioxide is less than 400ppm, the first valve, the third return valve and the first return valve are closed, and the third valve is opened.

7. The algal carbon capture device of claim 1, wherein said carbon capture of said carbon capture system comprises the steps of: (1) Extracting and separating from plant ash to obtain saturated potassium carbonate solution; (2) Introducing the initial gas source into the saturated potassium carbonate solution to absorb carbon dioxide to obtain a first solution; (3) Heating the first solution to release carbon dioxide gas and collecting.

8. The method of using the carbon capture device of any one of claims 1 to 7, comprising the steps of:

s1a: obtaining a carbon dioxide gas source in the initial gas source through the carbon capture system, and controlling the concentration of carbon dioxide in the carbon dioxide gas source to be less than or equal to 1400ppm through the pressure control unit;

s2a: introducing the carbon dioxide gas source into the closed algae biological reaction unit to perform the primary photosynthesis, and discharging the primary tail gas through the primary tail gas outlet;

s3a: if the concentration of the carbon dioxide in the primary tail gas is 800-1200 ppm, introducing the primary tail gas into the algae biological reaction unit again for primary photosynthesis; if the concentration of carbon dioxide in the primary tail gas is 400-800 ppm, introducing the primary tail gas into the closed plant culture unit for the secondary photosynthesis, and discharging the secondary tail gas through the secondary tail gas outlet;

s4a: if the concentration of carbon dioxide in the secondary tail gas is more than or equal to 400ppm, introducing the secondary tail gas into the algae biological reaction unit again for the primary photosynthesis; and if the concentration of carbon dioxide in the secondary tail gas is less than 400ppm, emptying the secondary tail gas through the first exhaust port.

9. The method of using the carbon capture device of any one of claims 1 to 7, comprising the steps of:

s1b: obtaining a carbon dioxide gas source in the initial gas source through the carbon capture system, and controlling the concentration of carbon dioxide in the carbon dioxide gas source to be less than or equal to 1400ppm through the pressure control unit;

s2b: introducing the carbon dioxide gas source into the closed algae biological reaction unit to perform the primary photosynthesis, and discharging the primary tail gas through the primary tail gas outlet;

s3b: if the concentration of carbon dioxide in the primary tail gas is more than or equal to 400ppm, concentrating the primary tail gas and introducing the initial gas source again for carbon capture; and if the concentration of carbon dioxide in the primary tail gas is less than 400ppm, emptying the primary tail gas through the second exhaust port.

10. The method of using the carbon capture device of any of claims 1 to 7, comprising the steps of:

s1c: obtaining a carbon dioxide gas source in the initial gas source through the carbon capture system, and controlling the concentration of carbon dioxide in the carbon dioxide gas source to be less than or equal to 1400ppm through the pressure control unit;

s2c: introducing the carbon dioxide gas source into the closed algae biological reaction unit to perform the primary photosynthesis, and discharging the primary tail gas through the primary tail gas outlet;

s3c: if the concentration of the carbon dioxide in the primary tail gas is 800-1200 ppm, introducing the primary tail gas into the algae biological reaction unit again for primary photosynthesis; if the concentration of carbon dioxide in the primary tail gas is 400-800 ppm, introducing the primary tail gas into the closed plant culture unit for the secondary photosynthesis, and discharging the secondary tail gas through the secondary tail gas outlet;

s4c: if the concentration of carbon dioxide in the secondary tail gas is more than or equal to 400ppm, concentrating the secondary tail gas, and introducing the initial gas source again for carbon capture; and if the concentration of carbon dioxide in the secondary tail gas is less than 400ppm, emptying the secondary tail gas through the first exhaust port.