A system for synergistically regulating the photo-thermal effect of a microalgae carbon fixation reactor in a glass house

Abstract

This invention relates to photobioreactor technology and aims to provide a system for synergistically regulating the photothermal effect of a microalgae carbon fixation reactor in a glass chamber. It includes: a glass chamber and multiple sets of photobioreactors; each set of photobioreactors includes several spaced-apart column reactors, with their upper and lower ends connected to horizontally arranged top and bottom manifolds, respectively; the top and bottom manifolds have right-angle bends in the middle, resulting in a staggered parallel layout of the photobioreactors; the multiple sets of photobioreactors are arranged parallel to each other, with the staggered layout creating a bend in the airflow path between adjacent photobioreactors; air inlets and exhaust fans are respectively installed on the sides of the glass chamber opposite to the ends of the airflow path, with the inlet side of the airflow path opposite the air inlet and the outlet side opposite the exhaust fan. This invention utilizes airflow impact to disrupt the thermal boundary layer of traditional straight-flow photobioreactors, enhancing convective heat dissipation.

Description

Technical Field

[0001] This invention pertains to photobioreactor technology and relates to a system for synergistically regulating the photothermal effect of a microalgae carbon fixation reactor in a glass chamber. Background Technology

[0002] Microalgae carbon fixation technology is an important form of carbon capture, utilization and storage (CCUS) technology, with a carbon fixation rate more than ten times that of general terrestrial plants. At the same time, microalgae are highly adaptable to the environment, do not compete with crops for land, and are rich in high-quality protein, making them extremely promising for large-scale industrial promotion.

[0003] In large-scale microalgal carbon sequestration projects, column-type photobioreactors are commonly used, with an external glass enclosure to protect against typhoons. However, this combination faces severe high-temperature risks in the summers of low-latitude southern regions. Due to the limitations of photosynthetic efficiency, the vast majority of solar radiation is converted into heat energy, heating the algal solution and the reactor. Furthermore, the greenhouse effect of the glass enclosure itself hinders long-wave radiation heat dissipation, causing the temperature of the algal solution inside the reactor to frequently exceed the microalgae's temperature tolerance limit. This high temperature not only significantly inhibits the activity of key enzymes in microalgal photosynthesis and reduces the carbon sequestration rate, but also induces oxidative stress and membrane system damage in microalgae, leading to reduced biomass production or even crop failure.

[0004] Conventional cooling measures in the existing technology have obvious drawbacks: spray cooling consumes a lot of water resources, and high humidity environment can easily have an adverse effect on metal structures and electrical equipment; if water is recycled, the spray nozzles are easily clogged by debris or scale; although external shading can cool down, it will greatly reduce photosynthetically effective radiation, significantly reduce the carbon sequestration of microalgae, and is easily damaged by typhoons outdoors.

[0005] Furthermore, the vertical reactors suffer from mutual shading, resulting in insufficient sunlight in the lower and middle sections. The concrete floor, the largest surface area inside the glass enclosure, absorbs a significant amount of solar radiation and heats up rapidly. This heat is then continuously transferred to the air and the reactor, wasting light resources and exposing the algal solution to the risk of overheating. If only highly reflective materials are laid on the floor for diffuse lighting, most of the increased radiant energy received by the reactor will be absorbed by the algal solution, leading to an expansion of the high-temperature zone within the reactor.

[0006] Therefore, the core challenge in achieving continuous and stable operation of the project is to effectively improve the system's heat dissipation capacity without reducing photosynthetically active radiation as much as possible, and to resolve the technical difficulty of reserving light radiation and the temperature rise of algal liquid. Summary of the Invention

[0007] The technical problem to be solved by the present invention is to overcome the shortcomings of the prior art and provide a system for synergistically regulating the photothermal effect of a microalgae carbon fixation reactor in a glass room.

[0008] To solve the technical problem, the solution of the present invention is:

[0009] A system for synergistically regulating the photothermal effect of a microalgae carbon fixation reactor in a glass room is provided, comprising a glass room and multiple sets of photobioreactors for microalgae carbon fixation installed on the floor of the glass room; each set of photobioreactors includes several spaced-apart column reactors, the upper and lower ends of which are connected to horizontally arranged top manifolds and bottom manifolds, respectively; the top and bottom manifolds have right-angle bends in the middle, making the projection of the photobioreactor Z-shaped; that is, the photobioreactor includes two parallel sections and a vertically connected section in the middle, with an overall staggered parallel layout;

[0010] The multiple photobioreactors are arranged in parallel with each other, and the staggered layout between adjacent photobioreactors forms a tortuous airflow path; an air inlet and an exhaust fan are respectively set on the side of the glass room opposite to both ends of the airflow path, with the inlet side of the airflow path opposite to the air inlet and the outlet side opposite to the exhaust fan.

[0011] As a preferred embodiment of the present invention, the lower edge of the induced draft fan and the air inlet is 1 to 2 meters above the ground.

[0012] As a preferred embodiment of the present invention, a wet curtain cooling device is installed on the indoor side of the air inlet.

[0013] As a preferred embodiment of the present invention, the two parallel and staggered sections in the photobioreactor have a middle turning section whose length is half the distance between the two sets of adjacent photobioreactors.

[0014] As a preferred embodiment of the present invention, in the photobioreactor, the column reactor is a cylindrical reactor made of acrylic material with a diameter of 85 mm to 110 mm and a height of 3.8 m to 4.2 m; the top manifold and the bottom manifold are made of PVC material.

[0015] As a preferred embodiment of the present invention, in the same group of photobioreactors, the spacing between adjacent column reactors is the same as their diameter; the spacing between adjacent photobioreactors is approximately 1 m to 1.5 m.

[0016] As a preferred embodiment of the present invention, the induced draft fan is a counterweight negative pressure fan with a power of 1-1.3 kW and a ventilation volume of 44,000 m³ / s. 3 / h.

[0017] The glass room of the reactor is a Venlo-type glass greenhouse with a modular structure of ridge and gutter; its top and sides are covered with coated glass as the light-transmitting covering material, combined with a hot-dip galvanized light steel frame, and the ground is paved with non-metallic reflective material.

[0018] The coated glass of the reactor is glass with coatings on both the inner and outer sides or single-silver coated glass, with an infrared transmittance of 0.15~0.05 and a visible light transmittance of not less than 0.75; the reflectivity of the non-metallic reflective material is not less than 0.8.

[0019] The non-metallic reflective material of the reactor is a reflective film or reflective non-woven fabric laid in a flexible manner; or a fluorocarbon coating or white epoxy resin floor paint that forms a cured coating by coating.

[0020] Compared with the prior art, the beneficial effects of the present invention are:

[0021] This invention reduces the temperature of the algal solution and the reactor by adjusting the reactor arrangement and the height of the ventilation openings in the glass chamber, using low-emissivity coated glass, and laying reflective material on the floor of the glass chamber. Specifically:

[0022] 1. By arranging multiple sets of photobioreactors in parallel with each other, the staggered layout of adjacent photobioreactors creates a tortuous airflow path; the airflow impact can be used to disrupt the thermal boundary layer of traditional straight-flow photobioreactors, thereby enhancing convective heat dissipation.

[0023] 2. By adjusting the installation height of the exhaust fan and air inlet, the airflow sweeping area can be increased; at the same time, by installing a wet curtain device at the air inlet, the air inlet temperature can be further reduced to below 33°C even under extreme high temperature weather conditions.

[0024] 3. By using low-emissivity coated glass on the roof and sides of the glass chamber, the infrared radiation from sunlight can be blocked, reducing the temperature of the glass and the reactor. Further, laying reflective materials on the ground can improve the reactor's lighting conditions while simultaneously lowering the ground temperature and reducing radiative heat exchange between the heated ground and the reactor. Attached Figure Description

[0025] Figure 1 This is a layout for multiple photobioreactors.

[0026] Figure 2 This describes the layout of a photobioreactor within a glass enclosure.

[0027] The attached diagram is labeled as follows: Top manifold 1; Bottom manifold 2; Vertical reactor 3; Glass room floor 4; Air inlet 5; Exhaust fan 6; Glass room roof 7; Glass room side 8. Detailed Implementation

[0028] The present invention will be further described in detail below with reference to specific embodiments.

[0029] Part One: Overview of the Invention Technical Solution

[0030] The system for synergistically regulating the photothermal effect of microalgae carbon fixation reactors in a glass room provided by the present invention includes a glass room and multiple photobioreactors for microalgae carbon fixation installed on the floor of the glass room.

[0031] As an optional example, the glass room is a Venlo-type glass greenhouse with a modular structure consisting of a ridge and gutters. Its roof and sides use coated glass as the light-transmitting covering material, coupled with a hot-dip galvanized light steel frame, and the ground is paved with non-metallic reflective material. The coated glass is glass with coatings on both the inner and outer sides, or single-silver coated glass, with an infrared transmittance of 0.15~0.05 and a visible light transmittance of not less than 0.75. The non-metallic reflective material has a reflectivity of not less than 0.8 and can be a flexible reflective film or reflective non-woven fabric, or a fluorocarbon coating or white epoxy resin floor paint that forms a cured coating through a coating process.

[0032] Each photobioreactor group includes several spaced-apart column reactors. The upper and lower ends of the column reactors are connected to the horizontally arranged top manifold and bottom manifold, respectively. The top manifold and bottom manifold have a right-angle bend design in the middle, so that the projection of the photobioreactor is Z-shaped. That is, the photobioreactor includes two parallel sections and a vertical connection section in the middle, and the whole is arranged in a staggered parallel layout.

[0033] As an optional example, the photobioreactor comprises two parallel and staggered sections, with the length of the intermediate turning section being half the distance between the two adjacent photobioreactor groups. In the photobioreactor, the column-type reactor is a cylindrical reactor made of acrylic material, with a diameter of 85 mm to 110 mm and a height of 3.8 m to 4.2 m; the top manifold and bottom manifold are made of PVC. Within the same group of photobioreactors, the distance between adjacent column-type reactors is the same as their diameter; the distance between adjacent photobioreactors is approximately 1 m to 1.5 m.

[0034] The multiple photobioreactors are arranged in parallel, alternating with each other, and the staggered arrangement between adjacent photobioreactors creates a tortuous airflow path. Air inlets and exhaust fans are respectively installed on the sides of the glass chamber opposite to both ends of the airflow path, with the inlet side of the airflow path opposite the air inlet and the outlet side opposite the exhaust fan. A wet curtain cooling device is installed on the indoor side of the air inlet.

[0035] As an optional example, the lower edge of the exhaust fan and air inlet is 1–2 m above the ground. The exhaust fan is a gravity-type negative pressure fan with a power of 1–1.3 kW and a ventilation volume of 44,000 m³ / h. 3 / h.

[0036] Part Two: Examples and Comparative Cases

[0037] Example 1:

[0038] In a system for synergistically regulating the photothermal effect of a microalgae carbon fixation reactor in a glass chamber:

[0039] (1) The diameter of the column-type photobioreactor is 110 mm and the height is 3.8 m. The spacing between adjacent tube rows is 1.2 m and the offset distance (i.e. the length of the intermediate turning section) is 0.6 m.

[0040] (2) Air inlets and exhaust fans are installed on the north and south sides of the glass room, respectively. The exhaust fan power is 1.0 kW, and the lower edge of both is installed at a height of 1.5 m from the ground. After being cooled by the wet curtain cooling device on the air inlet side, the air temperature entering the sunroom is 32℃.

[0041] (3) The roof and sides of the glass room are made of low-emissivity double-coated glass with an infrared transmittance of 0.05 and a visible light transmittance of 0.88.

[0042] (4) The glass room floor is covered with reflective non-woven fabric with a reflectivity of 0.82.

[0043] The system in this embodiment is located in Guangzhou, and the highest temperature of the algal solution in the reactor is 42.3℃. The microalgae were cultivated using the culture process described in the reference "Three-dimensional cellular structure analysis and environmental adaptation mechanism of microalgae converting and utilizing CO2 from power plant flue gas." Analysis of the harvested biomass confirmed a protein content of 48.5%, which is consistent with the expected microalgae culture content.

[0044] Example 2:

[0045] In a system for synergistically regulating the photothermal effect of a microalgae carbon fixation reactor in a glass chamber:

[0046] (1) The diameter of the column-type photobioreactor is 95 mm and the height is 4.2 m. The spacing between adjacent tube rows is 1.5 m and the offset distance (i.e. the length of the intermediate turning section) is 0.75 m.

[0047] (2) Air inlets and exhaust fans are installed on the north and south sides of the glass room, respectively. The exhaust fan power is 1.3 kW, and the lower edge of both is installed at a height of 2 m from the ground. After being cooled by the wet curtain cooling device on the air inlet side, the air temperature entering the sunroom is 30.7℃.

[0048] (3) The roof and sides of the glass room are made of low-emissivity double-coated glass with an infrared transmittance of 0.15 and a visible light transmittance of 0.83.

[0049] (4) The glass room floor is coated with white epoxy resin floor paint with a reflectivity of 0.84.

[0050] The system in this embodiment is located in Guangzhou, and the highest temperature of the algal solution in the reactor is 40.1℃. The microalgae were cultivated using the culture process described in the reference "Three-dimensional cellular structure analysis and environmental adaptation mechanism of microalgae converting and utilizing CO2 from power plant flue gas." Analysis of the harvested biomass confirmed a protein content of 50.9%, which is consistent with the expected microalgae culture content.

[0051] Example 3:

[0052] In a system for synergistically regulating the photothermal effect of a microalgae carbon fixation reactor in a glass chamber:

[0053] (1) The diameter of the column-type photobioreactor is 85 mm and the height is 4.0 m. The spacing between adjacent tube rows is 1.0 m and the offset distance (i.e. the length of the intermediate turning section) is 0.5 m.

[0054] (2) Air inlets and exhaust fans are installed on the north and south sides of the glass room, respectively. The exhaust fan power is 1.1 kW, and the lower edge of both is installed at a height of 1 m above the ground. After being cooled by the wet curtain cooling device on the air inlet side, the air temperature entering the sunroom is 28℃.

[0055] (3) The roof and sides of the glass room are made of low-emissivity single-layer coated glass with an infrared transmittance of 0.09 and a visible light transmittance of 0.75.

[0056] (4) A highly reflective ground film with a reflectivity of 0.80 is installed on the floor of the glass room.

[0057] The system in this embodiment is located in Guangzhou, and the highest temperature of the algal solution in the reactor is 37.6℃. The microalgae were cultivated using the culture process described in the reference "Three-dimensional cellular structure analysis and environmental adaptation mechanism of microalgae converting and utilizing CO2 from power plant flue gas." Analysis of the harvested biomass confirmed a protein content of 49.2%, which is consistent with the expected microalgae culture content.

[0058] Comparative Example 1

[0059] The operation was the same as in Example 1, with the same outdoor temperature and light conditions. The only difference was that the photobioreactor used a straight-line structure, without the staggered layout in the middle.

[0060] During the operation of the photobioreactor, the highest temperature of the algal solution reached 45.7℃; the crude protein content of the final harvested algal powder was 46.4%.

[0061] Comparative Example 2

[0062] The operation is the same as in Example 1, with the outdoor temperature and light conditions being identical. The only difference is that air inlets and outlets are provided on the opposite sides of the glass enclosure at both ends of the airflow path, without an exhaust fan.

[0063] During the operation of the photobioreactor, the highest temperature of the algal solution reached 67.8℃; the crude protein content of the final harvested algal powder was %. All microalgae died during the cultivation process.

[0064] Comparative Example 3

[0065] The operation is the same as in Example 1, with the same outdoor temperature and light conditions. The only difference is that conventional glass is used only on the top and sides of the glass room, instead of low-emissivity coated glass.

[0066] During the operation of the photobioreactor, the highest temperature of the algal solution reached 47.9℃; the crude protein content of the final harvested algal powder was 42.4%.

[0067] Comparative Example 4

[0068] The operation is the same as in Example 1, with the same outdoor temperature and lighting conditions. The only difference is that only a cement floor is used, and no reflective material is laid.

[0069] During the operation of the photobioreactor, the highest temperature of the algal solution reached 40.9℃; the crude protein content of the final harvested algal powder was 46.1%.

[0070] The above comparative examples 1-4 all involve building multiple photobioreactors in a glass room, but with some key design changes, in order to evaluate the impact of the design changes on the final cultivation effect.

[0071] The data from the above examples and comparative studies show that when the reactor is arranged in a completely straight line (without a central misalignment or bend), the thermal boundary layer on its surface develops fully, leading to deterioration of heat transfer on the reactor surface and an increase in the maximum temperature of the algal solution. Without an induced draft fan, the reactor relies solely on natural convection for heat dissipation, which is far less efficient than the forced convection cooling provided by an induced draft fan. The maximum temperature of the algal solution is significantly higher than the temperature that the microalgae can tolerate, ultimately leading to cultivation failure. When ordinary glass is used instead of low-emissivity coated glass, the infrared radiation from the sun causes the glass temperature to rise, thereby enhancing radiative heat transfer to the reactor and increasing the temperature of the algal solution. While the temperature of the algal solution decreases when no reflective material is laid on the ground, insufficient light at the bottom of the reactor reduces the photosynthetic rate of the microalgae, resulting in reduced protein synthesis and a decrease in crude protein content.

[0072] Specific embodiments of the present invention have been described above. It should be understood that the present invention is not limited to the specific embodiments described above, and those skilled in the art can make various modifications or variations within the scope of the claims, which do not affect the essence of the present invention.

Claims

1. A system for synergistically regulating the photothermal effect of a microalgal carbon fixation reactor in a glass chamber, comprising a glass chamber and multiple photobioreactors for microalgal carbon fixation installed on the floor of the glass chamber; characterized in that, Each photobioreactor group includes several spaced-apart column reactors. The upper and lower ends of the column reactors are connected to the horizontally arranged top manifold and bottom manifold, respectively. The top manifold and bottom manifold have a right-angle bend design in the middle, so that the projection of the photobioreactor is Z-shaped. That is, the photobioreactor includes two parallel sections and a vertical connection section in the middle, and the whole is arranged in a staggered parallel layout. The multiple photobioreactors are arranged in parallel with each other, and the staggered layout between adjacent photobioreactors forms a tortuous airflow path; an air inlet and an exhaust fan are respectively set on the side of the glass room opposite to both ends of the airflow path, with the inlet side of the airflow path opposite to the air inlet and the outlet side opposite to the exhaust fan.

2. The system according to claim 1, characterized in that, The lower edge of the induced draft fan and air inlet is 1 to 2 meters above the ground.

3. The system according to claim 1, characterized in that, A wet curtain cooling device is installed on the indoor side of the air inlet.

4. The system according to claim 1, characterized in that, The photobioreactor consists of two parallel and staggered sections, with the length of the intermediate turning section being half the distance between the two adjacent photobioreactors.

5. The system according to claim 1, characterized in that, In the photobioreactor, the column reactor is a cylindrical reactor made of acrylic material with a diameter of 85 mm to 110 mm and a height of 3.8 m to 4.2 m; the top manifold and bottom manifold are made of PVC material.

6. The system according to claim 1, characterized in that, In the same group of photobioreactors, the distance between adjacent column reactors is the same as their diameter; the distance between adjacent photobioreactors is approximately 1m to 1.5m.

7. The system according to claim 1, characterized in that, The induced draft fan is a counterweight negative pressure fan with a power of 1–1.3 kW and a ventilation volume of 44,000 m³. 3 / h.

8. The system according to any one of claims 1 to 7, characterized in that, The glass room is a Venlo-type glass greenhouse with a modular structure consisting of a ridge and gutters. Its top and sides are covered with coated glass as the light-transmitting material, and it is equipped with a hot-dip galvanized light steel frame. The ground is paved with non-metallic reflective materials.

9. The system according to claim 8, characterized in that, The coated glass is glass with coatings on both the inner and outer sides or single-silver coated glass, with an infrared transmittance of 0.15~0.05 and a visible light transmittance of not less than 0.75; the reflectivity of the non-metallic reflective material is not less than 0.

8.

10. The system according to claim 8, characterized in that, The non-metallic reflective material is a reflective film or reflective non-woven fabric laid in a flexible manner; or a fluorocarbon coating or white epoxy resin floor paint that forms a cured coating through a coating process.

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