JP3565468B2 - Photosynthetic culture device - Google Patents

Description

[0001]
TECHNICAL FIELD OF THE INVENTION
The present invention relates to an apparatus for culturing photosynthetic microorganisms such as algae (hereinafter referred to as a photosynthetic culture apparatus) for biologically fixing CO ₂ by photosynthesis and reducing CO ₂ in the atmosphere. BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an apparatus which, when used well, supplies light to photosynthetic microorganisms in a culture solution to efficiently grow the photosynthetic microorganisms.
[0002]
[Prior art]
Emissions of carbon dioxide (hereinafter referred to as CO ₂ ) due to combustion of fossil fuels are enormous in Japan, amounting to about 1.2 billion tons per year. In recent years, as one of the causes of global warming, an increase in CO _{2 in} the atmosphere has become a problem, and a technology for reducing CO ₂ has been demanded. Various technologies for reducing this CO ₂ have been researched and developed, but for practical use, a technology capable of minimizing energy consumption and reducing a large amount of CO ₂ is required.
[0003]
The technology for biologically fixing and reducing CO ₂ by photosynthesis is expected to be an environmentally friendly technology because sunlight can be used as energy and no by-products that pollute the environment are produced. As a method of cultivating photosynthetic microorganisms using sunlight, an open pond method of cultivating outdoors under sun irradiation is well known as a method of directly using sunlight. However, when a large amount of culture is performed in this method, the light transmission distance is short from the liquid level, so that a large liquid depth cannot be obtained, and as a result, there is a large disadvantage that a large site area is required.
[0004]
On the other hand, for biological CO ₂ fixation using photosynthesis, the following culturing techniques and the like are known as photosynthetic culturing devices capable of utilizing sunlight or artificial light with high efficiency and having a large liquid depth. For example, as disclosed in JP-A-50-157581, an external irradiation type photosynthetic culture apparatus that supplies light from the outside of a culture tank using a material such as glass that transmits light as an outer wall, and JP-A-57-102181. There is an internal irradiation type photosynthetic culture apparatus which supplies light by guiding light into a culture tank from an external light source by an optical transmission medium such as an optical fiber as disclosed in Japanese Patent Application Laid-Open No. 61-139382. Further, as disclosed in Japanese Patent Application Laid-Open No. 6-165669, by providing a culture area for directly irradiating sunlight and a culture area for irradiating transmitted light in the depth direction of the culture tank, light considering the depth direction is provided. There is an internal irradiation type photosynthetic culture device that is used efficiently.
[0005]
[Problems to be solved by the invention]
In the conventional external irradiation type photosynthetic culture apparatus, it is necessary to enlarge a tank wall or the like made of a light-transmitting material such as glass in order to increase the irradiation area. There is a problem that it is extremely difficult to increase the size of the culture tank. In addition, in this external irradiation type photosynthetic culture device, when the concentration of the photosynthetic microorganisms is high, the distance that the light reaches is short, and there is a problem that the amount of supplied light is insufficient and the growth of the photosynthetic microorganisms is suppressed. I have.
[0006]
On the other hand, in the internal irradiation type photosynthetic culture apparatus, it is possible to increase the light emission area by increasing the number of light scatterers attached to the inside of the tank. Avoid distance problems.
[0007]
However, the internal irradiation type photosynthetic culture device basically needs to condense sunlight or artificial light and transmit it to the inside of the culture tank. When using sunlight in an internal irradiation type photosynthetic culture device, as a device for condensing, there are a condensing lens and a condensing mirror. Only direct light incident as parallel rays can be used. There is a problem on the efficiency of use of sunlight that scattered light generated by the reflection of the atmosphere or clouds cannot be incident and used.
[0008]
Further, in order to condense the light to be supplied to the internal irradiation type photosynthetic culture device, the light receiving surface of the condenser needs to keep a certain angle (for example, vertical) with respect to the direct light, and for that purpose The trouble is that you have to track the sun. Furthermore, it is difficult at present to condense and transmit 100% of sunlight (direct light) with these condensing devices. Also, when using artificial light, basically, like sunlight, it is necessary to collect light, transmit it into the culture tank, and radiate it. Media is required.
[0009]
As described above, the internal irradiation type photosynthetic culture device having the conventional light-collecting function has a problem in that the light use efficiency is low, and a large cost is required for a light use system including light collection, transmission, and radiation.
[0010]
In view of the above-mentioned problems, the present invention provides a photosynthetic culture device having a high light utilization efficiency and a high photosynthetic ability per unit light receiving area, that is, a CO ₂ fixing ability, with a simple device, to prevent global warming. The purpose is to contribute.
[0011]
[Means for Solving the Problems]
In order to solve the above problems, the present invention provides a photosynthetic culture device for culturing photosynthetic microorganisms, wherein a culture tank, a culture solution contained in the culture tank, and light are supplied to the inside of the culture solution. has not provided a condenser lens which is immersed in the culture liquid for planar optical scatterer, the top of the optical synthetic culture device forms a light receiving portion of the solar light, the light receiving unit, sunlight A photosynthetic culturing apparatus, comprising: a culture solution surface to which direct light and scattered light can be incident; and a light incident end face of the light scatterer to which direct light and scattered light of sunlight can be incident.
[0012]
In the photosynthetic culture device, the light scatterer may be a flat light scatterer having a function of scattering and emitting incident light from a surface other than the light incident end face. In the photosynthetic culture apparatus, the light scatterers are vertically arranged such that the end opposite to the light incident end face is located at the bottom of the culture tank, and are arranged in a plurality of rows at intervals on the same plane. It is characterized by having.
[0013]
In the photosynthetic culture apparatus, a gas containing carbon dioxide can be discharged as bubbles from the bottom of the culture tank, and the discharged bubbles can rise between a plurality of rows of light scatterers and on the surface of the light scatterers, The rising of the air bubbles causes a vertical circulating flow of the culture solution, and the circulating flow has a function of constantly updating the culture solution near the light receiving portion on the surface of the culture solution. And in the vicinity of the light scatterer.
[0014]
The light scatterer used in the photosynthetic culture device of the present invention has a structure in which the light incident end face is not provided with a condenser lens or the like, so that both direct light and scattered light can be incident. In addition, the light receiving section is composed of a culture solution surface and light incident end faces of a plurality of rows of light scatterers that maintain a certain interval and protrude from the culture solution surface, and any surface of the light receiving portion is directly reached. Since both light and scattered light can be incident, both sunlight and artificial light can be efficiently incident and used.
[0015]
Since the light scatterer used in the photosynthetic culture apparatus of the present invention can scatter and radiate the incident light on all surfaces except the light incident end face, the light scatterer converts the incident sunlight or artificial light. It can be efficiently supplied into the culture solution in the culture tank. In the photosynthetic culture apparatus of the present invention, since the light scatterer is immersed in the deep part of the tank where light cannot be supplied from the liquid surface, light can be supplied to any part of the culture tank, and the direct light such as a conventional open pond can be used. The photosynthetic ability per unit light receiving area is higher than that of the photosynthetic culture device of the light receiving type.
[0016]
In the photosynthetic culture apparatus of the present invention, gas containing CO ₂ is discharged as bubbles from the bottom of the culture tank, and the agitation and mixing can be performed so as to generate a vertical flow of the culture solution by a lift effect due to the rise of the bubbles. Therefore, it is possible to positively promote the renewal of the culture solution in the vicinity of the upper liquid surface of the culture tank where the light supply amount is the largest, and therefore, promote the cultivation of photosynthetic microorganisms, and photosynthetic ability per unit light receiving area, ₂ Improve fixability.
[0017]
Further, the plate surface of the plate-shaped light scatterer becomes a space partitioned by other opposing plate surfaces, and a vertical circulation flow portion of the culture solution is formed in this space, so that the vertical circulation flow of the culture solution is further increased. The above-mentioned renewal effect of the culture solution can be enhanced by devising the arrangement of the light scatterers so as to be smooth.
[0018]
The photosynthetic culturing apparatus of the present invention has a plurality of rows of independent light scatterers kept at a constant interval in the culture tank, and can supply light at a uniform light supply density into the culture solution. Even when the scale-up is performed, the light supply density can be easily made constant, and the photosynthetic culture apparatus can be increased in size.
[0019]
BEST MODE FOR CARRYING OUT THE INVENTION
An embodiment of the present invention will be described with reference to the drawings. FIG. 1 is a diagram showing an example of the overall outline of a photosynthetic culture device according to the present invention. FIG. 2 is a sectional view taken along the line A-A in FIG. In the figure, reference numeral 1 denotes a culture tank, and 2 denotes a flat light scatterer immersed in a culture solution 8 contained in the culture tank 1. The flat light scatterer 2 has a light incident end face 3 at one end thereof, and can radiate light entering from the light incident end face 3 from the entire surface of the flat light scatterer 2 other than the light incident end face 3. It is a structure.
[0020]
As the flat light scatterer 2 in the photosynthetic culture device of the present invention, for example, a light scatterer described in JP-A-8-262232 can be used. The light scatterer described in the publication has a structure in which a light scattering surface is formed and light incident from an end face can be uniformly scattered from the entire transparent plate.
[0021]
The flat light scatterer 2 in the photosynthetic culture apparatus of the present invention has one end face as it is as a light incident end face, and has a structure that does not have a condensing function, so that both direct light and scattered light are simultaneously incident. Has the ability to do. The plate-shaped light scatterer 2 has a vertically long shape, and a plurality of rows are vertically arranged in the culture tank 1 at regular intervals on the same plane so that the vertical direction is the depth direction of the culture tank 1. It is arranged so that the end opposite to the light incident end face 3 is located at the bottom in the culture tank.
[0022]
However, the shape of the flat light scatterer 2 in the photosynthetic culture device of the present invention is not limited to a vertically long shape. In addition, the structure is not limited to the light scatterer described in Japanese Patent Application Laid-Open No. 8-262232, as long as the structure allows light to enter from one end surface and scatter and radiate the incident light from the entire surface.
[0023]
Reference numeral 4 denotes a culture solution surface, and the light incident end face 3 of the flat light scatterer 2 is disposed so as to protrude above the culture solution surface 4 in order to directly receive light. 5 is sunlight or artificial light. Reference numeral 6 denotes a ventilation pipe for supplying CO ₂ required for photosynthesis, and the ventilation pipe 6 communicates with a sparger 10 for discharging a gas containing CO ₂ . The sparger 10 has many fine openings suitable for discharging gas, and is disposed at the bottom in the culture tank 1 and in the vicinity of each flat light scatterer 2.
[0024]
Sunlight or artificial light 5 is supplied to the culture solution surface 4 and the light incident end surface 3 of the flat light scatterer 2. The light to be supplied can be either direct light or scattered light. The light entering from the light incident end face 3 of the flat light scatterer 2 is scattered and radiated from the entire surface of the flat light scatterer 2 and supplied to the deep part of the culture tank 1.
[0025]
The air 7 containing CO ₂ is discharged from the bottom in the culture tank 1 upward through the sparger 10 shown in FIG. Air 7 including the exhaled CO ₂ supplies the CO ₂ to photosynthetic microorganisms, causing the vertical circulating flow of broth as culture medium flow pattern 11 shown by an arrow in FIG. 2 by gas lift effect. This circulating flow promotes the renewal of the culture solution 8 near the culture solution surface 4 with a large amount of supplied light, and enables photosynthetic microorganisms to perform efficient photosynthesis. The upper part of the photosynthetic culture apparatus may be open, and if necessary, for example, a light-transmissive lid may be provided for the purpose of gas management, prevention of contamination, and the like.
[0026]
As shown in FIGS. 1 and 2, the flat light scatterers 2 are arranged in a plurality of rows on the same plane so that a wall having a gap is formed on the flat surface thereof. By discharging the gas 7 containing CO ₂ from the bottom of the culture tank 1 between the two walls, the culture solution 8 is smoothly and two-dimensionally moved toward the wall formed by the flat light scatterers 2. The vertical up-and-down circulation flow occurs.
[0027]
Reference numeral 8 in FIG. 1 denotes a culture solution to be supplied, which supplies a micronutrient source or the like to the photosynthetic microorganisms in the culture tank 1. The 9 is withdrawn culture, can be effectively utilized, such as the separated collected photosynthetic microorganism is a CO ₂ fixation product from the withdrawn culture 9.
[0028]
【The invention's effect】
According to the photosynthetic culturing apparatus of the present invention, sunlight or artificial light can be directly supplied to the culture solution from the culture solution surface, and light can be supplied from the light incident end of the light scatterer to the deep portion of the culture tank. High photosynthetic capacity per area.
[0029]
In addition, according to the photosynthetic culture device of the present invention, since both direct light and scattered light can be used, the efficiency of using sunlight is high. In particular, since the light incident end face of the light scatterer for internal irradiation can also enter the direct light and the scattered light, the sunlight use efficiency is higher than that of the conventional internal irradiation device that receives only direct light.
[0030]
Further, according to the photosynthetic culturing apparatus of the present invention, since it has a function of circulating and flowing the culture solution such that the culture solution having a large amount of received light near the surface of the culture solution that is directly irradiated with sunlight or artificial light can be renewed, Photosynthesis can be performed efficiently.
[0031]
In addition, according to the photosynthetic culture device of the present invention, since the light scatterer is not provided with a condensing device, a light transmission fiber, and the like, the construction cost is significantly reduced as compared with the conventional condensing type photosynthetic culture device. Has an effect that can be.
[0032]
By using the photosynthetic culture device according to the present invention, CO ₂ , which is one of the substances causing global warming, can be biologically fixed efficiently, and can contribute to global environmental conservation.
[Brief description of the drawings]
FIG. 1 shows an overall outline of a photosynthetic culture apparatus of the present invention.
FIG. 2 shows an A-A cross section of FIG.
[Explanation of symbols]
Culture 10 spargers 11 culture flow pattern extracting air 8 cultures 9 containing 1 fermenter 2 planar optical scatterers 3 light incident end face 4 culture surface 5 sunlight or artificial light 6 vent pipe 7 CO ₂

Claims (2)

In a photosynthetic culture device for culturing photosynthetic microorganisms,
A culture tank, a culture solution contained in the culture tank, and a flat light scatterer without a condenser lens immersed in the culture solution for supplying light into the culture solution,
The upper part of the photosynthetic culture device forms a light receiving part for sunlight ,
Light receiving unit includes a feature the direct light and the scattered light and the culture liquid surface possible incidence of sunlight, that the direct light and the scattered light of the sunlight is composed of the light incident end face of the possible incident light scatterer Photosynthetic culture device. The flat light scatterer without the condensing lens is vertically arranged such that the end opposite to the light incident end face of sunlight is located at the bottom of the culture tank, and is spaced on the same plane. Are arranged in a plurality of rows, and a gas containing carbon dioxide can be discharged from the bottom of the culture tank as bubbles, and the discharged bubbles can rise between the plurality of rows of light scatterers and on the surface of the light scatterers. The rising of the bubbles causes a vertical circulating flow of the culture solution, and the ventilation flow has a function of constantly updating the culture solution near the light receiving portion on the culture solution surface by the circulating flow. 2. The photosynthetic culture device according to claim 1, wherein the photosynthetic culture device is provided at the bottom and near the light scatterer.

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