JP2013162762A - Apparatus for culturing photosynthetic microorganism - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an apparatus for culturing photosynthetic microorganisms, which efficiently dissolves carbon dioxide in a culture solution with low operation energy.SOLUTION: An apparatus for culturing photosynthetic microorganisms includes a carbon dioxide dissolution device 4 separately from a culture tank 2A that holds a culture solution C and cultures the photosynthetic microorganisms in the culture solution C. By the carbon dioxide dissolution device 4, carbon dioxide is dissolved in the culture solution C from the culture tank 2A under a water pressure that is higher than that of the culture solution C in the culture tank 2A and the culture solution having the dissolved carbon dioxide is fed to the culture tank 2A. Consequently, carbon dioxide is efficiently dissolved in the culture solution C with low operation energy in comparison with the case in which aeration facilities are installed over the whole culture tank 2A.

Description

  The present invention relates to a photosynthetic microorganism culture apparatus for culturing photosynthetic microorganisms that absorb light energy and take in carbon dioxide during photosynthesis.

  In recent years, photosynthetic microorganisms that absorb light energy during photosynthesis and take in and fix carbon dioxide, the cause of global warming, have attracted attention. Here, in order to activate the absorption of carbon dioxide by the photosynthetic microorganism, it is required to efficiently dissolve the carbon dioxide in the culture solution for culturing the photosynthetic microorganism. As a configuration that meets such a requirement, for example, Patent Document 1 below includes an aeration facility that releases carbon dioxide by microbubble aeration for an algal pound (culture unit) for containing a culture solution and performing culture. It is described that it is provided.

Special table 2010-519926

  As described above, when an aeration facility is provided in the culture section, in order to efficiently dissolve carbon dioxide, for example, it is conceivable to provide an aeration facility over the entire culture section. However, in such a case, the operating energy for operating the aeration facility increases.

  The present invention has been made to solve such problems, and an object thereof is to provide a photosynthetic microorganism culturing apparatus capable of efficiently dissolving carbon dioxide in a culture solution with a small amount of operating energy.

  A photosynthetic microorganism culturing apparatus according to the present invention is a photosynthetic microorganism culturing apparatus for culturing in a culture solution a photosynthetic microorganism that absorbs light energy and takes in carbon dioxide during photosynthesis. A culture section for culturing photosynthetic microorganisms in the liquid, and a dissolution tank for storing the culture liquid. In the dissolution tank, the culture liquid from the culture section is subjected to a pressure higher than that of the culture liquid in the culture section. A carbon dioxide dissolving part for dissolving carbon dioxide and supplying a culture solution in which the carbon dioxide is dissolved to the culture part.

  In the photosynthetic microorganism culturing apparatus according to the present invention, a carbon dioxide dissolving part is provided separately from the culture part, and this carbon dioxide dissolving part allows the culture solution from the culture part to be under a water pressure higher than the water pressure of the culture solution in the culture part. In contrast, carbon dioxide is dissolved, and the culture solution in which the carbon dioxide is dissolved is supplied to the culture section. For this reason, compared with the case where aeration equipment is provided over the entire culture unit, carbon dioxide can be efficiently dissolved in the culture solution with less operating energy.

  Here, when the water depth in the dissolution tank is deeper than the water depth in the culture section, the contact time between the culture solution and carbon dioxide in the dissolution tank becomes longer than the contact time between the culture solution and carbon dioxide in the culture section. Therefore, carbon dioxide is more easily dissolved in the culture solution. For this reason, in the photosynthetic microorganism culturing apparatus according to the present invention, carbon dioxide can be more efficiently dissolved in the culture solution than when an aeration facility is provided in the culture section.

  ADVANTAGE OF THE INVENTION According to this invention, it becomes possible to provide the photosynthetic microorganism culture apparatus which can melt | dissolve a carbon dioxide efficiently with respect to a culture solution, without increasing operating energy.

It is a schematic plane block diagram which shows 1st embodiment which concerns on the photosynthetic microorganism culture apparatus of this invention. It is a schematic sectional drawing which shows the carbon dioxide melt | dissolution apparatus in FIG. It is a schematic plane block diagram which shows 2nd embodiment which concerns on the photosynthetic microorganism culture apparatus of this invention.

  Hereinafter, embodiments of the photosynthetic microorganism culturing apparatus of the present invention will be described with reference to the drawings. In addition, the same code | symbol is attached | subjected to the same or an equivalent element, and the overlapping description is abbreviate | omitted.

[First embodiment]
FIG. 1 is a schematic plan view showing a first embodiment according to the photosynthetic microorganism culturing apparatus of the present invention. As shown in FIG. 1, the photosynthetic microorganism culturing apparatus 1A cultivates a photosynthetic microorganism in a culture solution C, and absorbs and immobilizes carbon dioxide by photosynthesis of the photosynthetic microorganism.

  The photosynthetic microorganisms cultured in the photosynthetic microorganism culture apparatus 1A absorb light energy as an energy source and take in carbon dioxide as a carbon source during photosynthesis. Examples of such photosynthetic microorganisms include Euglena and photosynthetic bacteria in addition to photosynthetic microalgae. Among these, photosynthetic microalgae include, for example, Botryococcus braunii of the genus Botryococcus and Pseudochoricystisellipsoidea of the genus Pseudochoricystis. Can be mentioned. These photosynthetic microalgae produce beneficial substances such as petroleum-like hydrocarbons (oils and fats) through photosynthesis.

  A photosynthetic microorganism culturing apparatus 1A for culturing such photosynthetic microorganisms includes a culture tank (culture unit) 2A, a water wheel 3 and a carbon dioxide dissolving device (carbon dioxide dissolving unit) 4.

  The culture tank 2A is a tank that contains a culture solution C for culturing photosynthetic microorganisms and cultures the photosynthetic microorganisms in the culture solution C. Here, the culture tank 2A is a raceway type and has an elliptical circulation channel. The culture tank 2A is irradiated with sunlight from the sun when installed outdoors, and is irradiated with light from a light source provided in the room or tank when installed indoors. The water depth in the culture tank 2A is made shallow, for example, about 50 cm or less so that light can reach the bottom of the tank sufficiently, so that photosynthetic microorganisms can perform photosynthesis well.

  The water turbine 3 forms a flow of the culture solution C in the culture vessel 2A in order to prevent the culture solution C from staying in the culture vessel 2A and appropriately culture the photosynthetic microorganism, and constitutes the culture vessel 2A. It is provided in the middle of the circulation channel. This water wheel 3 forms the flow of the culture solution C in the culture tank 2A by sending the culture solution C from one to the other. Note that a submersible pump or the like may be used instead of the water wheel 3 as the flow forming means.

  The carbon dioxide dissolution apparatus 4 is for dissolving carbon dioxide in the culture solution C, and is provided separately from the culture tank 2A. FIG. 2 is a schematic cross-sectional view showing the carbon dioxide dissolving apparatus in FIG. As shown in FIG. 2, the carbon dioxide dissolution apparatus 4 includes a carbon dioxide dissolution tank 41, a culture solution introduction tube 42, a culture solution return tube 43, a gas introduction tube 44, a gas supply unit 45, a porous air diffuser 46, and a gas. A discharge pipe 47 is provided.

  The carbon dioxide dissolution tank 41 is a tank for containing the culture solution C, and here has a hollow sphere shape. The water depth d in the carbon dioxide dissolution tank 41 is set to be deeper than the water depth in the culture tank 2A, and is about 100 to 300 cm here.

  The culture medium introduction pipe 42 is a pipe for introducing the culture medium C from the culture tank 2A to the carbon dioxide dissolution tank 41, and communicates the culture tank 2A and the carbon dioxide dissolution tank 41 (see FIG. 1). Here, the culture solution introduction tube 42 is connected to a side portion of the carbon dioxide dissolution tank 41. The culture solution introduction tube 42 is provided with an introduction amount adjustment valve 42a for adjusting the introduction amount of the culture solution C. The culture medium introduction pipe 42 is provided with a pump P that serves as a power source when introducing the culture medium C.

  The culture solution return pipe 43 is a pipe for returning the culture solution C from the carbon dioxide dissolution tank 41 to the culture tank 2A, and communicates the culture tank 2A and the carbon dioxide dissolution tank 41 (see FIG. 1). Here, the culture solution return tube 43 is connected to the side of the carbon dioxide dissolution tank 41 and below the culture solution introduction tube 42. The culture solution return tube 43 is provided with a return amount adjustment valve 43a for adjusting the return amount of the culture solution C. The return of the culture medium C is performed together with the introduction of the culture medium C by the power of the pump P described above.

  The gas introduction pipe 44 is a pipe for introducing carbon dioxide into the carbon dioxide dissolution tank 41, and connects the carbon dioxide dissolution tank 41 and a gas supply unit 45 capable of supplying high concentration and high pressure carbon dioxide. ing. Here, the gas introduction pipe 44 is connected to the lower end portion of the carbon dioxide dissolution tank 41 and enters the carbon dioxide dissolution tank 41.

  The porous air diffuser 46 is an apparatus for dissolving carbon dioxide in the culture medium C, and is installed inside the dissolution tank 41. The porous diffuser 46 includes a porous diffuser plate 46a, a lower flange 46b, an upper flange 46c, and an O-ring 46d.

  The porous diffuser plate 46a is for making the carbon dioxide introduced from the gas introduction pipe 44 into fine bubbles, and has a substantially disk shape here. The porous diffuser plate 46a can be formed of, for example, a porous ceramic material, a sintered alloy, a polymer compound, or the like. The pore size of the porous diffuser plate 46a is, for example, about 1 to 500 μm. The smaller the pore diameter, the better the carbon dioxide can be dissolved in the culture solution C.

  The lower flange 46b has a substantially disk shape, and the above-described gas introduction pipe 44 is inserted through and inserted into a substantially central portion thereof. The upper flange 46c has a substantially cylindrical shape, and is provided with a flange 46e protruding inward at the upper end thereof. Then, the porous diffuser plate 46a is inserted into the upper flange 46c and sandwiched between the flange 46e and the lower flange 46b from above and below, and an O-ring 46d is interposed between the porous diffuser plate 46a and the lower flange 46b. In this state, the porous diffuser plate 46a is fixed by connecting the lower flange 46b and the upper flange 46c by, for example, bolt fastening. Thereby, a space into which carbon dioxide from the gas introduction pipe 44 enters is provided between the porous diffuser plate 46a and the lower flange 46b.

  The gas discharge pipe 47 is a pipe for discharging the gas inside the carbon dioxide dissolution tank 41 to the outside, and communicates the inside and the outside of the carbon dioxide dissolution tank 41. The gas discharge pipe 47 is connected to the upper end portion of the carbon dioxide dissolution tank 41 here. The gas discharge pipe 47 is provided with a gas discharge amount adjustment valve 47a for adjusting the discharge amount of gas.

  Next, the operation of the photosynthetic microorganism culture apparatus 1A will be described.

  In the photosynthetic microorganism culturing apparatus 1A, light is irradiated to the photosynthetic microorganism in the culture solution C in the culture tank 2A, and photosynthesis is performed by the photosynthetic microorganism. Further, a circulating flow of the culture solution C is formed in the culture tank 2A by the water wheel 3.

  In the carbon dioxide dissolution apparatus 4, the culture medium C is introduced from the culture tank 2 </ b> A to the carbon dioxide dissolution tank 41 through the culture liquid introduction pipe 42 by the pump P. Further, carbon dioxide is supplied from the gas supply unit 45 through the gas introduction pipe 44, and the carbon dioxide that has entered the space between the porous diffuser plate 46a and the lower flange 46b passes through the porous diffuser plate 46a. Ascend in the culture medium C. When passing through the porous diffuser plate 46a, the carbon dioxide becomes fine bubbles, a part of which is dissolved in the culture solution C on the way up the culture solution C, and the remainder not dissolved is in the carbon dioxide dissolution tank 41. Accumulate at the top. The carbon dioxide accumulated in the upper part of the carbon dioxide dissolution tank 41 is discharged to the outside of the carbon dioxide dissolution tank 41 through the gas discharge pipe 47. Then, the culture medium C in which carbon dioxide is dissolved is supplied from the carbon dioxide dissolution tank 41 to the culture tank 2A through the culture liquid return pipe 43. Thus, the culture solution C is circulated between the culture tank 2A and the carbon dioxide dissolving device 4.

  Here, in the carbon dioxide dissolution tank 41, the water pressure of the culture solution C is adjusted to the water pressure of the culture solution C in the culture tank 2A by adjusting the introduction amount adjustment valve 42a, the return amount adjustment valve 43a, and the gas discharge amount adjustment valve 47a. Higher, for example, about 0.2 to 5 MPa. In general, the higher the water pressure of the culture solution C, the easier the carbon dioxide dissolves in the culture solution C. Therefore, in the carbon dioxide dissolution tank 41, carbon dioxide is well dissolved in the culture solution C with less operating energy.

  As described above, in the photosynthetic microorganism culturing apparatus 1A according to the present embodiment, the carbon dioxide dissolution apparatus 4 is provided separately from the culture tank 2A, and the water pressure higher than the water pressure of the culture solution C in the culture tank 2A is provided by the carbon dioxide dissolution apparatus 4. Below, carbon dioxide is melt | dissolved with respect to the culture solution C from the culture tank 2A, and the culture solution C in which the said carbon dioxide was dissolved is supplied to the culture tank 2A. Therefore, for example, carbon dioxide can be efficiently dissolved in the culture solution C with less operating energy than when aeration equipment is provided over the entire culture tank 2A.

  In the photosynthetic microorganism culturing apparatus 1A, since the water depth in the carbon dioxide dissolution tank 41 is deeper than the water depth in the culture tank 2A, the contact time between the culture solution C and carbon dioxide in the carbon dioxide dissolution tank 41 is different in the culture tank 2A. This is longer than the contact time between the culture medium C and carbon dioxide. For this reason, it becomes easier to dissolve carbon dioxide in the culture solution C, and carbon dioxide can be more efficiently dissolved in the culture solution C than in the case where an aeration facility is provided in the culture tank 2A.

  Here, for example, when the aeration equipment is directly provided in the culture tank 2A, since the culture solution C is in the atmosphere, carbon dioxide is not dissolved in the culture solution C, and bubbles are generated in the culture solution C. May damage the photosynthetic microorganisms. In contrast, in the photosynthetic microorganism culturing apparatus 1A, in the carbon dioxide dissolving apparatus 4 provided separately from the culture tank 2A, the carbon dioxide is well dissolved in the culture liquid C, and the culture liquid in a state where the carbon dioxide is dissolved. Since C is supplied to the culture tank 2A, damage to the photosynthetic microorganism can be suppressed. In addition, since the amount of the culture solution C present in the culture vessel 2A is larger than the amount of the culture solution C supplied from the carbon dioxide dissolving device 4 to the culture vessel 2A, the carbon dioxide is dissolved. Is supplied to the culture tank 2A under the atmosphere, the amount of carbon dioxide that returns to the bubbles is small, and damage to the photosynthetic microorganisms can be suppressed. Moreover, when the pH of the culture solution C in the culture tank 2A is high, the amount of carbon dioxide that returns to the bubbles is further reduced.

  Further, in the photosynthetic microorganism culturing apparatus 1A, the carbon dioxide dissolution tank 41 has a deeper water depth than the culture tank 2A, and therefore, for example, the porous aeration apparatus 46 is compared to the case where the porous aeration apparatus 46 is provided in the culture tank 2A. Can be installed easily.

  In the photosynthetic microorganism culturing apparatus 1A, as described above, since carbon dioxide can be efficiently dissolved in the culture medium C, photosynthetic microorganisms can be cultured well, and photosynthetic microalgae that produce fats and oils as photosynthetic microorganisms are cultured. When it does, it becomes possible to improve the production | generation efficiency of fats and oils.

[Second Embodiment]
FIG. 3 is a schematic plan view showing a second embodiment according to the photosynthetic microorganism culturing apparatus of the present invention. As shown in FIG. 3, the photosynthetic microorganism culturing apparatus 1B according to the second embodiment is different from the photosynthetic microorganism culturing apparatus 1A according to the first embodiment (see FIG. 1) in place of the raceway type culture tank 2A. Thus, an open pond type culture tank 2B is used.

  Specifically, the culture tank 2B is a circular tank, and blades 5 that form the flow of the culture solution C extend in the culture tank 2B from the center to the outside in the radial direction. The blade 5 is rotatably fixed to the central portion of the culture tank 2B, and forms a flow of the culture solution C in the culture tank 2B by rotating and moving in the culture tank 2B.

  It goes without saying that such a photosynthetic microorganism culturing apparatus 1B has the same operations and effects as the photosynthetic microorganism culturing apparatus 1A according to the first embodiment.

  As mentioned above, although embodiment which concerns on the photosynthetic microorganism culture apparatus of this invention was described, this invention is not limited to the said embodiment. For example, in the above embodiment, the porous air diffuser 46 is installed inside the carbon dioxide dissolution tank 41, but instead, for example, a tube-type aeration or the like may be installed. Is sufficient if it can generate fine bubbles of carbon dioxide in the culture medium C.

  Moreover, in the said embodiment, although the dissolution tanks 2A and 2B which are tanks are used as a culture part, it replaces with this and the culture pond which is a pond may be used.

DESCRIPTION OF SYMBOLS 1A, 1B ... Photosynthetic microorganism culture apparatus, 2A, 2B ... Culture tank (culture part), 4 ... Carbon dioxide dissolution apparatus (carbon dioxide dissolution part), 41 ... Carbon dioxide dissolution tank (dissolution tank).

Claims (2)

A photosynthetic microorganism culturing apparatus for culturing a photosynthetic microorganism that absorbs light energy and takes in carbon dioxide during photosynthesis in a culture solution,
A culture unit for containing the culture solution and culturing the photosynthetic microorganism in the culture solution;
A dissolution tank containing the culture solution, and in the dissolution tank, carbon dioxide is dissolved in the culture solution from the culture unit under a water pressure higher than the water pressure of the culture solution in the culture unit; A carbon dioxide dissolving part for supplying a culture solution in which carbon dioxide is dissolved to the culture part;
A photosynthetic microorganism culture apparatus comprising:   The photosynthetic microorganism culturing apparatus according to claim 1, wherein a water depth in the dissolution tank is deeper than a water depth in the culture unit.

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