JPH0838158A - Co2 immobilizing apparatus by fine algae - Google Patents

Abstract

PURPOSE:To reduce theinstallation cost and operation cost and effectively remove CO2 in discharge gas. CONSTITUTION:A carrier 28 is arranged in a closed type reactor 24 capable of irradiating light into the interior. Fine algae 29 are retained on the carrier 28. A discharge gas 21 containing CO2 is fed from a feed pipe 23 into the reactor 24 and a liquid medium 25 is fed from the pipe 27. These fine algae 29 are irradiated with light and CO2 is immobilized by photosynthetic reaction of the fine algae 29 and discharged as a treated gas 31 from a discharge pipe 32.

Description

Detailed Description of the Invention

[0001]

FIELD OF THE INVENTION The present invention uses microalgae to directly fix CO ₂ in the atmosphere, and is included in exhaust gas from thermal power plants, boilers, waste treatment plants, water treatment plants, automobiles, and the like. The present invention relates to a CO ₂ immobilization device that immobilizes CO ₂ that is retained.

[0002]

_2. Description of the Related Art FIG. 16 shows a conventional CO ₂ immobilization method. In FIG. 16, an exhaust gas 1 containing CO ₂ from a thermal power plant or the like is supplied by a blower 2 to a diffuser pipe 4 in a reaction tank 5 via a gas pipe 3. A liquid medium 6 and microalgae 7 are put into the reaction tank 5 to form a culture solution 8. The microalgae 7 uses the supplied CO ₂ as a carbon source, the mineral in the liquid medium as a nutrient source, and the light energy of the irradiated light 9 as an energy source to cause the photosynthetic reaction shown in Formula (1), CO ₂ in the exhaust gas 1 is C ₆ H ₁₂ O
Immobilize as ₆ (organic matter). CO ₂ is immobilized and C
The gas having a reduced O ₂ concentration is discharged as a processing gas 10 through a gas pipe 11. Further, the on-off valve 12 is opened at any time, and the liquid medium 6 is supplied into the reaction tank 5 via the pipe 13.

[0003]

[0004]

However, the conventional methods for immobilizing CO ₂ by microalgae have the following problems.

That is, as the operation is continued, the concentration of the microalgae 7 increases, and it becomes difficult for the light 9 to reach the inside of the culture liquid 8, for example, 10 cm or less from the liquid surface. Further, as the concentration of the microalgae 7 increases, the irradiation of the light 9 is blocked and the CO ₂ immobilization rate decreases.

Similarly, when the operation is continued, it becomes difficult for the light 9 to reach the inside of the culture broth 8, which makes it difficult to fabricate a large-sized plant in the vertical direction. You have to make a plant. Therefore, the installation area of the reaction tank 5 becomes large.

Culture liquid 8 (water, nutrients, microalgae)
Since the photosynthetic reaction is carried out in the liquid phase by using water, a large amount of water and nutrient salts are required, and the supply cost of them becomes high.

Further, since the exhaust gas 1 is supplied into the culture solution 8 (water, nutrient salts, microalgae) and the photosynthetic reaction is carried out in the liquid phase, the light irradiation area must be enlarged when the reaction tank 5 is enlarged. Although it must be done, if the size is increased, a large amount of blower 2, gas pipe 3 and diffuser pipe 4 for generating bubbles are required,
Construction costs are high. Moreover, the electric cost of the blower 2 becomes enormous, and it is difficult to make it into an actual plant.

Further, when the reaction tank 5 is enlarged, it is necessary to stir the inside of the liquid phase, but it is not possible to stir the inside of the liquid phase of the reaction tank 5 uniformly only by bubbling with the blower 2. The electricity cost for stirring is high.

Further, when the grown microalgae 7 are collected and used for fuel, chemicals, etc., it is necessary to carry out a concentration step such as precipitation separation and centrifugation, but the installation area of this concentration step And the electric cost of the process increases.

The present invention has been made in consideration of the above points, and reduces the installation area by improving the utilization efficiency of light and increasing the CO ₂ fixing rate, and reduces water and nutrient salts. By reducing running costs and construction costs such as use, operation of blowers, agitation of culture solution, concentration and recovery of microalgae, CO in exhaust gas or atmospheric air
It is an object of the present invention to provide a method for immobilizing CO _{2 with} microalgae, which can immobilize ₂ efficiently and practically.

[0012]

According to the first aspect of the present invention,
A closed reaction tank for holding microalgae for immobilizing CO ₂ gas in a state in which the microalgae can be irradiated with light; a means for supplying exhaust gas containing CO ₂ gas into the reaction tank; An apparatus for immobilizing CO ₂ by microalgae, comprising: a means for discharging a processing gas from the tank, and a means for supplying water to the microalgae in the reaction tank.

The invention according to claim 2 is the CO ₂ immobilization device by microalgae according to claim 1, wherein the ratio of the water volume to the exhaust gas supply space volume in the reaction tank is 1 or less.

The invention according to claim 3 is the apparatus for immobilizing CO ₂ by microalgae according to claim 1, characterized in that the microalgae are retained on the side wall in the reaction tank.

The invention according to claim 4 is characterized in that the microalgae are held by a plate-shaped carrier in the reaction tank, and the carriers are horizontally arranged in multiple stages in the reaction tank. It is a CO ₂ immobilization device using microalgae.

The invention according to claim 5 is characterized in that the microalgae are held by a plate-shaped carrier in the reaction tank, the carrier is arranged at an angle, and a partition is provided on the carrier. It is a CO ₂ immobilization device using the microalgae described in 1.

The invention as set forth in claim 6 is characterized in that the microalgae are held by a carrier in the reaction tank, the carrier is arranged on the carrying means, and a driving device for driving the carrying means is provided. C according to claim 1
This is an O ₂ immobilization device.

The invention according to claim 7 is characterized in that the microalgae are held in contact with the material obtained by processing the combustion ash or the combustion charcoal in the reaction tank. ₂ Immobilization device.

The invention according to claim 8 is characterized in that in order to circulate the gas in the exhaust gas supply space of the reaction tank, a circulation pipe is provided in the reaction tank, wherein CO _{2 is} immobilized by microalgae. It is a device.

The present invention as set forth in claim 9 is characterized in that the exhaust gas supply means is provided with a cooling device for cooling the exhaust gas temperature to 60 ° C. or less, and CO by microalgae as set forth in claim 1.
₂ Immobilization device.

[0021] The invention according to claim 10 includes a closed reaction tank in which light is irradiated, and microalgae for floating CO ₂ gas in the closed reaction tank and fixing CO ₂ gas. The granular carrier to be held and CO into the gas phase in the reaction tank
_An apparatus for immobilizing CO ₂ by microalgae, comprising: a means for supplying an exhaust gas containing _two gases; and a means for discharging a treated gas from the reaction tank.

According to the eleventh aspect of the present invention, an atmosphere open reaction tank for holding microalgae for immobilizing CO ₂ gas in a state capable of irradiating light to the microalgae, and a C
A microalgae comprising: a means for supplying exhaust gas containing O ₂ gas; a means for discharging processing gas from the reaction tank; and a means for supplying water to the microalgae in the reaction tank. It is a CO ₂ fixing device.

The invention according to claim 12 is the CO ₂ immobilization device by microalgae according to claim 11, characterized in that the means for supplying water is connected to a reservoir of rainwater or seawater.

According to a thirteenth aspect of the present invention, a closed type reaction tank for holding microalgae for immobilizing CO ₂ gas in a state capable of irradiating light to the microalgae, and CO _{2 in the} reaction tank.
Means for supplying exhaust gas containing gas, means for discharging processing gas from the reaction tank, means for supplying water to microalgae in the reaction tank, means for measuring water in the reaction tank and microalgae Among the means for measuring the photosynthetic activity, at least one measuring means, and means for controlling the supply of water to the microalgae based on the measurement value from this measuring means, by the microalgae characterized by It is a CO ₂ fixing device.

[0025]

According to the invention described in claim 1, when the exhaust gas containing CO ₂ is supplied to the reaction tank by the exhaust gas supply means and the water is supplied from the water supply means, the CO ₂ is supplied to the microalgae retained in the reaction tank. ₂ and water can be brought into contact with each other, and by irradiating the reaction tank with light, CO ₂ in the exhaust gas can be immobilized by the microalgae to reduce the CO ₂ in the exhaust gas. The gas is discharged as a processing gas.

According to the second aspect of the invention, the volume of the liquid phase with respect to the volume of the gas phase is set so that the liquid gas ratio is 1 or less, and the microalgae is contacted with the exhaust gas containing CO ₂ and irradiated with light. by can moisture supply small to secure the CO ₂ in the exhaust gas to reduce the CO _2.

According to the third aspect of the present invention, a large number of microalgae held on the reaction tank side are brought into contact with CO ₂ in the exhaust gas and moisture to irradiate light to perform photosynthesis, and CO in the exhaust gas is efficiently produced. ₂ can be fixed.

[0028] According to the invention as defined in claim 4, the microalgae retained on the surface of the carrier arranged in multiple stages is mixed with CO ₂ in the exhaust gas.
At the same time as bringing water into contact with water, photosynthesis is performed using light, and CO ₂ in the exhaust gas can be efficiently fixed.

According to the fifth aspect of the present invention, the partition walls provided on the surface of the carrier allow the water to be uniformly held on the surface of the carrier, and photosynthesis can be carried out by the microalgae. Further, by disposing the partition wall, the chances of contacting CO ₂ in the exhaust gas with the microalgae are increased, the CO ₂ immobilization rate of the microalgae is improved, and the CO ₂ in the exhaust gas is further reduced, and then treated. It can be discharged as gas.

According to the invention described in claim 6, during normal operation, the driving device is stopped, and when the water content on the surface of the microalgae decreases or the photosynthetic ability of the microalgae decreases at regular intervals, The means for supplying the water and the driving means for the transporting means are simultaneously operated to uniformly diffuse and retain the water on the surface of the carrier, and the microalgae perform photosynthesis.

According to the seventh aspect of the invention, the combustion ash or the material obtained by processing the combustion ash has an excellent ability to retain microalgae, and can firmly and rapidly retain microalgae on the carrier. In addition, combustion ash is SiO ₂ (silica), Al ₂ O
₃ (alumina) is the main component, and not only microalgae but also CO ₂ or other impurities (SOx,
NOx, SPM, etc.) are also adhered and removed, and discharged as a processing gas.

According to the invention described in claim 8, the gas in the reaction tank is circulated to increase the stirring strength and the turbulent flow strength in the reaction tank so that CO _{2 in} the exhaust gas and the microalgae may come into contact with each other. Increase the CO ₂ fixation rate,
Emission of process gas with ₂ reduced more.

According to the ninth aspect of the invention, the exhaust gas is supplied to the heat exchanger so that the temperature of the exhaust gas is about 10 at which the microalgae are killed.
Decrease from 0 ° C to about 60 ° C below viable. By supplying the gas whose temperature has dropped to the inside of the reaction tank, the inside of the reaction tank is maintained at a temperature at which microalgae can survive. The microalgae always stabilizes CO ₂ in a stable manner and discharges the processing gas in which CO ₂ is constantly reduced.

According to the tenth aspect of the invention, when the exhaust gas is allowed to flow, the granular carrier is floated in the reaction tank so that CO _{2 in} the exhaust gas and the microalgae retained on the surface of the carrier can be contacted with each other. Is increased, and more CO ₂ in the exhaust gas is fixed.

According to the eleventh aspect of the present invention, the atmospheric air is naturally mixed into the reaction tank open to the atmosphere so that CO
₂ , the microalgae held on the carrier, water, and light are brought into contact with each other to perform photosynthesis, thereby reducing CO ₂ in the atmosphere.

According to the twelfth aspect of the present invention, the rainwater or seawater is supplied to the surface of the microalgae, and the atmosphere is contacted with the microalgae and light to emit CO _{2 in the} atmosphere.
Can be fixed to reduce CO ₂ in the atmosphere.

According to the invention of claim 13, the water concentration on the surface of the microalgae or the CO ₂ immobilization rate of the microalgae is detected, and when the value is below a set value, water is supplied to the surface of the microalgae. To ensure stable CO ₂
The immobilization rate can be maintained.

[0038]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS First Embodiment An embodiment of the present invention will be described below with reference to the drawings. FIG. 1 is a diagram showing a first embodiment of a CO ₂ immobilization device using microalgae according to the present invention.

In FIG. 1, the CO ₂ immobilization apparatus comprises a closed reaction tank 24 and a plate-like carrier 28 horizontally arranged on the bottom of the reaction tank 24, and the carrier 28 is adhered to a support. It is made of glass fiber with a pore size of 1.0 μm. On the surface of the carrier 28 made of this glass fiber sheet, micro algae 29 having a diameter of about 10 μm for immobilizing CO ₂ gas is applied. As the microalgae 29, Chlorella quesrelii C- which has a high proliferative power
The 531 strain is used, and this microalgae 29 is retained in the gas phase.

The wall surface of the reaction tank 24 is light-transmissive, and the sunlight from the light source 30 passes through the wall surface of the reaction tank 24 and is applied to the surface of the microalgae 29. Further exhaust gas 2
1 is a reaction vessel 24 by a blower 22 via a supply pipe 23.
While the processing gas in the reaction tank 24 is supplied to the exhaust pipe 3.
It is discharged from 2 to the outside.

Further, the liquid medium 25 is supplied into the reaction tank 24 via a pipe 27 having an opening / closing valve 26.

Next, the operation of this embodiment having such a configuration will be described. First, the blower 22 supplies the supply pipe 23
The exhaust gas 21 is supplied into the reaction tank 24 via the. CO ₂ in the exhaust gas 21 supplied into the reaction tank 24 is expressed by the formula by the water and the nutrient salts in the liquid medium 25 supplied to the surface of the microalgae 29 and the light energy irradiated on the surface of the microalgae. The photosynthetic reaction shown in (1) occurs in the gas phase.
Due to this reaction, CO ₂ in the exhaust gas 21 becomes C ₆ H ₁₂ O ₆
(Organic matter) and O ₂ . The organic matter generated by the photosynthetic reaction is stored in the cells of the microalgae 29 or on the cell surface, and the generated O ₂ is discharged from the discharge pipe 32 as the processing gas 31 together with the unreacted CO ₂ . In this way, the CO ₂ concentration in the treated gas 31 is reduced by the amount immobilized by the microalgae 29, and the treated gas 31 in which the CO ₂ is reduced is reduced.
Is obtained.

Next, the microalgae 29 and the liquid medium 25 will be described. Since the microalgae 29 can cause a photosynthetic reaction if water is present inside, the surface of the microalgae 29 does not necessarily need to be covered with water. However, the water is supplied to the inside of the microalgae 29 from the surface of the microalgae 29.

In this embodiment, a pipe 27 having an opening / closing valve 26 is provided.
The liquid medium 25 is supplied into the reaction tank 24 from the liquid medium 25 having the composition shown in Table 1.

The compositions of the A5 solution and the Fe solution in Table 1 are shown in Tables 2 and 3, respectively.

[0046] Next, referring to FIG. 17 and FIG. 18, CO of microalgae 29 when pure water and liquid medium 25 were supplied into microalgae 29 consisting of Chlorella quesrelii C-531 strain.
₂ Shows the change in the amount of immobilization.

FIG. 17 shows microalgae 2 when either pure water or liquid medium 25 is supplied into microalgae 29.
9 shows the change in the amount of CO ₂ immobilized in Example 9. In this case, CO ₂ flows into the reaction tank 24 together with air. As shown in FIG. 17, no matter whether pure water or liquid medium 25 was supplied, the water content disappeared and the CO ₂ immobilization amount became 0 after two and a half days.

FIG. 18 shows the change in the amount of CO ₂ immobilized in the microalgae 29 when either pure water or the liquid medium 25 was regularly supplied into the microalgae 29. In this case, CO ₂ flows into the reaction tank 24 together with air.
As shown in FIG. 18, when the liquid medium is regularly supplied, the reduction in CO ₂ immobilization ability can be suppressed as compared with the case of pure water.

Incidentally, in FIG. 18, the microalgae 29 grow over time. When pure water is regularly supplied, microalgae 29 grow, for example, as shown in Table 4.

[0050] According to the present embodiment, since the glass fiber sandpaper is used as the carrier 28, the microalgae 29 can be easily held, and the pore size of the glass fiber sandpaper is 1.0 μm as compared with the diameter of the microalgae 29 of about 10 μm. Since it is small, the liquid medium 25 passes through the carrier 28 but the microalgae 29 do not pass through.

When the Chlorella quesrelii C-531 strain is used as the microalgae 29, the cells of the microalgae 29 are resistant to low water content, and therefore can be handled relatively roughly. Therefore, it is resistant to changes in water content, and a stable CO ₂ immobilization rate can be maintained.

Further, since sunlight is used as the light source 30 and solar energy is used as the energy source, it is not necessary to bring energy required for the photosynthetic reaction, that is, the CO ₂ fixing reaction from another source. Further, since the reaction tank 24 is a flat plate type, it has a simple structure, the construction cost of the reaction tank is low, and the operation management method is easy.

Further, the liquid medium 2 is simply opened / closed by the opening / closing valve 26.
5 can be supplied, and simple and low-cost supply is possible.

Although the liquid medium 25 was used to replenish the surface of the microalgae 29 with water, pure water and solid nutrient salts can be separately supplied, or they can be alternately supplied. Further, instead of the liquid medium 25, seawater, rainwater, or waste-related water such as sewage from a sewage treatment plant, treated water,
It is also possible to use treated water, etc. from a garbage treatment plant.

Next, a modified example of the present invention will be shown. In FIG. 1, glass fiber sandpaper is used as the carrier 28, but the type, number, particle size, shape, and size of the carrier are not limited. That is, a carrier 28 made of glass, acrylic, ceramics or the like can be used. Further, the carrier 28 is not necessarily provided, and the microalgae 29 may be provided directly on the wall surface of the reaction tank 24.

Chlorella quesrelii strain C-531 was used as the microalgae 29, but other species of the same genus Chlorella, chlorella pyrenoidosa, other green alga Donaliella, or spirulina, a member of the cyanobacteria, etc. Any biologically defined microalgae can be used. In addition, the carrier holding amount of the microalgae 29 is not particularly limited.

Further, although sunlight is used as the energy source, light other than sunlight can be used. For example,
Artificial light such as a fluorescent lamp derived from electric energy, fire light derived from thermal energy, or the like may be used, or sunlight and light other than sunlight may be mixed and used.

Although the structure of the reaction tank 24 is a flat plate type,
The structure, shape, type, number, and size of the reaction tank 24 are not limited. It may have a spherical or cylindrical structure, or a plurality of them may be arranged in parallel or in series.

The method of supplying the liquid medium 25 and the exhaust gas 21 is not limited to the method shown in FIG. For example, the liquid medium 25 can be supplied into the reaction tank 24 by a pump.

Second Embodiment Next, a second embodiment of the present invention will be described with reference to FIG.

In the second embodiment shown in FIG. 2, the ratio of the volume of water (liquid phase) 33 surrounding the microalgae 29 to the volume of the exhaust gas supply space (gas phase) 34 in the reaction tank 24 is 1 or less. For example, it is set to 0.1, and the others are substantially the same as those of the first embodiment shown in FIG.

The same parts as those of the first embodiment shown in FIG. 1 are designated by the same reference numerals and their detailed description will be omitted.

In FIG. 2, the liquid medium 25 is transferred to the microalgae 2 in the reaction tank 24 by opening the opening / closing valve 26 at appropriate times.
When it is supplied to the surface 9, liquid medium 25 comes into contact with the surface of the microalgae 29. In this case, the liquid medium 25 to be contacted,
That is, the ratio of the liquid phase portion 33 to the gas phase portion 34 (liquid gas ratio) is 0.1. Microalgae 29 is exhaust gas 21
And CO ₂ in, from the water in the liquid medium 25 with a light energy of the light source 30 causes a photosynthetic reaction shown in Equation (1), to immobilize CO ₂ in the flue gas 21. Process gas 31 containing immobilized remaining in CO ₂ with the immobilized occurred was the CO ₂ and other gas components without is discharged from the gas pipe 32.

According to this embodiment, since the liquid gas ratio is 0.1, the amount of the liquid medium 25 used can be reduced, and the liquid medium 25 can be used.
Supply costs are reduced. Further, since the microalgae 29 and the liquid medium 25 are in contact with each other at all parts except the contact surface between the microalgae 29 and the carrier 28, the surface of the microalgae 29 is mostly covered with the liquid medium 25. The biological activity of CO ₂ can be maintained high, and the CO ₂ fixation rate is stabilized.

Although the liquid gas ratio is 0.1, the value is not limited. It is sufficient that the surface of the microalgae 29 has a slight amount of water, that is, the liquid-gas equivalence ratio is 1 or less.

The contact surface between the microalgae 29 and the liquid medium 25 does not need to be all surfaces except the carrier contact surface, and the occupancy rate of this contact surface is not limited. Micro algae casting 2
It is sufficient for a part of the surface of 9 to contact the liquid medium 25, and the carrier 28 of the microalgae 29 may be contacted via the liquid medium 25.

As in the case of the first embodiment, the method of supplying the exhaust gas 21, the liquid medium 25, the type of the light source 30, the structure, shape, type, number, size of the reaction tank 24 and the carrier 28,
Further, the type and amount of the microalgae 29 are not limited.

Third Embodiment Next, a third embodiment of the present invention will be described with reference to FIG. FIG.
In the third embodiment shown in FIG. 3, the height of the reaction tank 24 is set to be substantially the same as that of the bottom, and the reaction tank 2 is added to the carrier 28 at the bottom of the reaction tank 24.
4 is provided with a carrier 28a made of glass fiber filter paper on the side wall, and is otherwise substantially the same as the first embodiment shown in FIG. Further, the pipe 27 for supplying the liquid medium has a connection point 35.
Is branched into a pipe 36 and a pipe 37, and the respective pipes 36 and 37 are connected to the upper side wall of the reaction tank 24.

In FIG. 3, the exhaust gas 21 supplied into the reaction tank 24 by driving the blower 22 comes into contact with the microalgae 29 held by the carriers 28, 28a. At this time, the water and the exhaust gas 21 of the liquid medium 25 existing on the surface of the microalgae 29
CO _{2 in} the formula (1) using the light energy of the light source 30
The photosynthetic reaction shown in (1) occurs and is converted to an organic substance and O ₂ . As shown in FIG. 3, since the microalgae 29 are held not only on the bottom of the reaction tank 24 but also on the side walls, the light source 30
The irradiation area is increased, the photosynthetic reaction is promoted, the CO ₂ in the exhaust gas 21 is more fixed, the CO ₂ is reduced, and the CO ₂ is discharged as the processing gas 31.

According to this embodiment, the liquid medium 25 is branched at the connection point 35 and is supplied to the upper side wall of the reaction tank 24 by the pipes 36 and 37. And the surface of the microalgae 29 arranged at the bottom can be filled with the liquid medium 25.

Further, since the tank height of the reaction tank 24b is lengthened, a larger amount of microalgae 29 can be held on the surface of the carrier 28a, thereby improving the CO ₂ immobilization rate.

The method of supplying the exhaust gas 21, the liquid medium 25, the type of the light source 30, the reaction tank 24 and the carriers 28, 28
Structure, shape, type, number, size of a, and microalgae 29
The type, amount, etc. of are not particularly limited.

Fourth Embodiment Next, a fourth embodiment of the present invention will be described with reference to FIG. FIG.
In the fourth embodiment shown in FIG. 1, the carriers are arranged in multiple stages in the horizontal direction, and the rest is substantially the same as the first embodiment shown in FIG.

As shown in FIG. 4, in the reaction tank 24, a first carrier 40, a second carrier 41, and a third carrier 42, which are made of acrylic, are arranged in this order from the top, and each carrier is provided. The first microalgae 43, the second microalgae 44, and the third microalgae 45 are held by 40, 41, and 42. The microalgae 43, 44, and 45 are all composed of Chlorella quesrelii C-531 strain. Further, the supply pipe 46 having the blower 22 is branched into a supply pipe 48 and a supply pipe 49 at a connection point 47, and the supply pipe 49 is further branched into a supply pipe 51 and a supply pipe 52 at a connection point 50. Further, the pipe 53 having the open / close valve 26 has a pipe 55 and a pipe 5 at a connection point 54.
6, and the pipe 56 branches into a pipe 58 and a pipe 59 at a connection point 57. An exhaust pipe 60 for exhausting the processing gas 31 is a combination of an exhaust pipe 62 and an exhaust pipe 63 at a connection point 61, and the exhaust pipe 63 has an exhaust pipe 65 and an exhaust pipe 66 at a connection point 64.
Is a merger.

In FIG. 4, the liquid culture medium 25 is supplied to the surfaces of the first microalgae 43, the second microalgae 44, and the third microalgae 45 by opening the opening / closing valve 26. Further, the exhaust gas 21 is supplied to the gas phase part where the first to third microalgae 43, 44, 45 are present by driving the blower 22, and the microalgae 43, 4 respectively.
Numerals 4 and 45 perform photosynthesis from water in the liquid medium 25 and CO ₂ in the exhaust gas, which come into contact with the surfaces of the respective microalgae 43, 44, and 45, using the light energy emitted from the light source 30, and in the exhaust gas 21. Of CO ₂ is fixed. At this time, the respective microalgae 43, 44, 45 perform photosynthesis,
The exhaust gas from which CO ₂ has been reduced is mixed at the connection point 61 and is discharged as the processing gas 31 via the discharge pipe 60.

According to this embodiment, since the liquid medium 25 is supplied only by opening / closing one opening / closing valve 26, operation management becomes easy. In addition, the first to third carriers 40, 4
Since light-transmissive acrylic is used as 1, 42, light passes through the respective carriers 40, 41, 42, reaches the second and third carriers, and not only the first microalgae 43 The second microalgae 44 and the third microalgae 45 also perform photosynthesis, and the CO ₂ fixation rate per area of the reaction tank 24 is improved. Therefore, the CO ₂ concentration in the processing gas 31 can be reduced.

Although acrylic was used as the material of the first carrier 40, the second carrier 41, and the third carrier 42, the kind, material, number, size, shape, color, etc. of the carrier are not limited.
Any material can be used as long as it is light transmissive.

The exhaust gas 21 and the liquid medium 25 are fed to the reaction tank 2
There is no particular limitation on the method of supplying the gas into the chamber 4 or the method of discharging the processing gas 31. Each microalga 4
It is possible to provide a blower, an on-off valve, or a pipe for supplying the surface of 3, 44, 45.

The same type of chlorella quesrelii was used as the microalgae 43, 44, 45, but other types of microalgae may be used, or different types of microalgae may be used for each carrier 4.
It is also possible to use it by holding it on the surface of 0, 41, 42.

The type of the light source 30 and the structure, shape, type, number and size of the reaction vessel 24 are not limited.

Fifth Embodiment Next, a fifth embodiment of the present invention will be described with reference to FIG. In the fifth embodiment shown in FIG. 5, a plate-shaped carrier is provided in an inclined manner in a reaction tank, and a partition wall is provided on this carrier. Others are substantially the same as those of the first embodiment shown in FIG. It is the same.

As shown in FIG. 5, the reaction tank 24 is tilted by the reaction tank support portion 79, and thus the plate-like carrier 28 provided in the reaction tank 24 is also tilted. On the surface of the carrier 28, the first partition 70, the second partition 71, and the third partition 7 are arranged in this order from the direction in which the exhaust gas 21 flows in and orthogonal to the inclination direction.
Second and fourth partition walls 73 are provided. Also, exhaust gas 2
A biomass recovery unit 78 is provided on the inflow side of 1.
Further, the reaction tank support portion 79 is provided on the discharge side of the processing gas 31, and the reaction tank 24 is inclined at 10 degrees from the horizontal direction. The partition walls 70 to 73 are fixed to the side wall of the reaction tank 24.

In FIG. 5, the microalgae 29 are held in advance on the surface of the carrier 28 between the partition walls 70, 71, 72 and 73. The liquid medium 25 is fed with microalgae 29 through a pipe 27.
And the liquid surface of the liquid culture medium 25 is formed by the fourth partition wall 73. When the supply of the microalgae 29 is further continued, the liquid medium 25 reaches the third partition wall 72 beyond the fourth partition wall 73. Similarly, the second partition 71 and the first partition 70
Also in the above, the liquid surface of the liquid medium 25 is formed, and all of the microalgae 29 retained on the surface of the carrier 28 are the liquid medium 2
Covered with 5. When the exhaust gas 21 is supplied into the reaction tank 24d in such a state, the microalgae 29 utilize the light energy of the light source 30 from the water in the liquid medium 25 covering the surface and the CO ₂ in the exhaust gas 21. Perform photosynthesis.
The gas in which CO ₂ is immobilized and CO ₂ is reduced is discharged from the discharge pipe 32 as the processing gas 31. Also microalgae 2
The increased amount of 9 and useful substances secreted by microalgae settle in the biomass recovery unit 78 and are discharged as the biomass 80 from the discharge pipe 77.

According to this embodiment, since the partition walls 70 to 73 are provided on the carrier 28 in the reaction tank 24 at right angles to the flow direction of the liquid medium 25, the liquid medium 25 is separated from the partition walls 70 to 73.
The microalgae 29 can stay in the space and completely fill the surface of the microalgae 29. Further, since the liquid medium 25 is supplied from one tube 76, the structure of the device is simplified and the operation management is facilitated. Furthermore, since the carrier 28 can be tilted by tilting the reaction tank 24 by the reaction tank support portion 79,
The liquid medium 25 can be supplied to the surface of the microalgae 29 by spontaneous fall, and the supply power can be reduced. Further, since the biomass recovery unit 78 is provided, the recovery of the biomass 80 becomes easy.

Although the partition walls 70 to 73 are arranged in the reaction tank 24 at right angles to the flow direction of the liquid medium 25, the number of partition walls, the installation direction, etc. are not limited. That is, it is possible to provide a gap without connecting the partition wall to the side wall of the reaction tank 24, or to arrange the partition walls 70 to 73 obliquely or vertically to the flow direction.

Although the reaction tank 24 is inclined by providing the reaction tank supporting portion 79 of the reaction tank 24, it is possible to tilt only the carrier 28 in the reaction tank 24 without using the reaction tank supporting portion 79. is there. Further, the inclination angle can be used in any range of 0 to 90 degrees, and the product can be delivered by a pump or the like without using the spontaneous dropping action.

Although the biomass recovery unit 78 is installed inside the reaction tank 24d, it may be installed outside instead of inside.

The method of supplying the exhaust gas 21, the liquid medium 25, the type of the light source 30, the structures, shapes, types, numbers, and sizes of the reaction tank 24 and the carrier 28, and the type and amount of the microalgae 29 are particularly important. Not limited.

Sixth Embodiment Next, a sixth embodiment of the present invention will be described with reference to FIG. The sixth embodiment shown in FIG. 6 is one in which the carrier in the reaction tank is arranged on the belt conveyor, and other than that is substantially the same as the first embodiment shown in FIG.

As shown in FIG. 6, a belt conveyor 82 is provided in the reaction tank 24, and a carrier 28 made of glass fiber filter paper is arranged on the belt conveyor 82.
The belt conveyor 82 is driven by a motor 81.

In FIG. 6, the motor 81 is rotated to drive the belt conveyer 82 to the right, and at the same time, the liquid medium 25 is discharged from the pipe 27 to the side of the processing gas 31 on the discharge side of the microalgae 2.
Supply to 9. The belt conveyor 82 is driven to change the position where the liquid medium 25 is picked up, and the entire surface of the microalgae 29 held on the surface of the carrier 28 is filled with the liquid medium. In addition, the components that are easily separated from the carrier 28, such as the grown amount of the microalgae 29 and the organic matter, are dropped to the bottom of the biomass recovery unit 78 and recovered as the biomass 80 from the discharge pipe 77. The microalgae 29 are arranged only on one surface of the belt conveyor 82 and are not arranged on the other surface. After sufficiently supplying the liquid medium 25 to the microalgae 29 on one surface, the driving of the belt conveyor 82 and the supply of the liquid medium 25 are stopped.

According to this embodiment, since the motor 80 and the belt conveyor 82 are used as the drive means for moving the carrier 28, the liquid medium 25 can be uniformly supplied to the surface of the microalgae 29 at a relatively low cost. .

The transport means for transporting the carrier 28 is not limited to the belt conveyor 82, and the method of supplying the exhaust gas 21 and the liquid medium 25, the reaction tank 24 and the carrier 28.
The structure, shape, number, size, inclination angle, etc. of are not limited.

Seventh Embodiment Next, a seventh embodiment of the present invention will be described with reference to FIG. The seventh embodiment shown in FIG. 7 is one in which a granular carrier holding microalgae is filled in a gas phase in a closed reaction tank in a suspended state. The same parts as those in the first embodiment shown in FIG. 1 are designated by the same reference numerals, and detailed description thereof will be omitted.

In FIG. 7, the reaction tank 24 has a cylindrical upper part and an inverted conical lower part, and a spherical plastic carrier having an air specific gravity of 1.0 is charged therein as a granular carrier 90. There is. On the surface of the granular carrier 90, Chlorella quesrelii C-531 strain is retained as microalgae 29. The light emitted from the sunlight as the light source 30 enters the inside of the reaction tank 24 from the side portion.

By driving the blower 22 in FIG. 7, the exhaust gas 21 is supplied into the reaction tank 24. Inside the reaction tank 24, the granular carrier 90 holding the microalgae 29 floats and flows in the reaction tank 24. Also,
From the pipe 27, the liquid medium 2 is opened by opening the on-off valve 26.
5 is supplied into the reaction tank 24, and the liquid medium 25 contacts the surface of the microalgae 29.

The microalgae 29 on the surface of the granular carrier 90 that is flowing comes into contact with CO ₂ in the exhaust gas 21 and the microalgae 29
Using the water in the liquid medium on the surface of and the light energy of the light source 30, a photosynthetic reaction is caused to immobilize CO ₂ .

According to this embodiment, since the plastic granular carrier 90 having an air specific gravity of 1.0 is used, the granular carrier 90 can be easily fluidized by supplying the exhaust gas 21. Therefore, the chances of contact between the microalgae 29 and the exhaust gas 21 are increased, and the CO ₂ fixation rate is improved. Further, since the light is incident from the side wall of the reaction tank 24, the irradiation area of the light is increased and the CO ₂ fixing rate is improved. Further reaction tank 2
Since the bottom of No. 4 has a conical shape, the flow state of the granular carrier 90 can be maintained well.

The shape, structure, etc. of the reaction tank 24 are not limited to those shown in FIG. 7. For example, the bottom may not be conical, but the whole may be cylindrical, and may be spherical or rectangular. Further, the type, material, property, number, etc. of the granular carrier 90 are not limited. As long as the exhaust gas 21 is supplied and fluidized, any one can be used.

Eighth Embodiment Next, an eighth embodiment of the present invention will be described with reference to FIG. The eighth embodiment shown in FIG. 8 is one in which microalgae 29 are arranged on the surface of combustion ash. The same parts as those in the first embodiment shown in FIG. 1 are designated by the same reference numerals, and detailed description thereof will be omitted.

In FIG. 8, a carrier 28 made of acrylic is disposed inside the reaction tank 24, and fly ash of a thermal power plant is bonded as combustion ash 91 to the surface of the carrier 28. In the upper part and the gap of the combustion ash 91 adhered to the surface of the carrier 28, chlorella quesrelii C as microalga 29
-531 strain is applied.

The main component of the composition of the fly ash which constitutes the combustion ash 91 coated on the surface of the carrier 28 is S
iO ₂ (silica) and Al ₂ O ₃ (alumina), and these two components have a property of adsorbing an organic substance. Therefore, the microalgae 29 are quickly and firmly held on the surface or the gap of the combustion ash 91. Due to the photosynthetic action of the microalgae 29, CO ₂ in the exhaust gas 21 is fixed. The main component of the combustion ash 91 is capable of removing SPM (particulate suspended matter), SO _x , and NO _x remaining in the exhaust gas 21, and is discharged as the processing gas 31.

According to the present embodiment, since fly ash is used as the combustion ash 91, the microalgae 29 are strongly supported by the carrier 2.
It is possible to maintain the temperature at 8 and a stable CO ₂ fixation rate can be obtained.

Although fly ash is used as the combustion ash 91, other ash can be used. For example,
Sludge incineration ash from a sewage treatment plant or incineration ash from a waste treatment plant may be used. Further, not only the combustion ash but also the one obtained by processing the combustion ash can be used. For example, fly ash can be fired to produce highly transparent glass, which can be used as a coating material. Further, not only the coating material but also the combustion ash or the combustion ash processed material can be used as the material of the carrier 28 or the inner wall of the reaction tank 24 itself.

Ninth Embodiment Next, a ninth embodiment of the present invention will be described with reference to FIG. In the ninth embodiment shown in FIG. 9, the reaction tank 24 is provided with a circulation pipe. The same parts as those of the first embodiment shown in FIG. 1 are designated by the same reference numerals, and detailed description thereof will be omitted.

In FIG. 9, one end of a circulation pipe 93 having a blower 92 is connected above the discharge pipe 32 of the reaction tank 24, and the other end of the circulation pipe 93 is connected above the supply pipe 23. There is.

In FIG. 9, the blower 22 is driven to supply the exhaust gas 21 into the reaction tank 24. At the same time, the blower 92 is driven to circulate the gas in the gas phase portion in the reaction tank 24 through the circulation pipe 93.
Circulate through. In this case, as shown in the equation (2), this circulation gas flow rate Q ₂ is equal to the gas flow rate Q of the exhaust gas 21.
Set to 10 times ₁ In the reaction tank 24, when the turbulent flow intensity in the gas phase portion increases and the gas flow rate is controlled, the microalgae 29
The chance of contact between CO ₂ in the exhaust gas 21 and CO ₂ increases. Therefore, the CO ₂ fixing rate is improved, and the processing gas 31 with a further reduced CO ₂ concentration can be obtained.

Q ₂ = 10 × Q ₁ Formula (2) According to this embodiment, the circulating gas flow rate Q ₂ is set to 10 times as in Formula (2), so that the turbulent flow intensity increases and CO _{2 is} fixed. Speed is improved. Since the circulation pipe 93 is disposed higher than the exhaust gas supply pipe 23 and the exhaust pipe 32, the gas mixing efficiency is improved, the contact efficiency between the microalgae 29 and CO ₂ is increased, and the CO ₂ fixation rate is increased. Is possible.

The circulating gas flow rate Q ₂ is not limited to the ratio of the equation (2). Further, the installation location of the circulation piping 93, the number thereof, the number and size of the blowers 93, etc. are not limited. It is also possible to install a plurality of circulation pipes 93. Further, the supply of the exhaust gas 21 and the liquid culture medium 25, the type of the light source 30, the type, the shape, the number, and the size of the reaction tank 24, the carrier 28, and the microalgae 29 are not particularly limited.

Tenth Embodiment Next, a tenth embodiment of the present invention will be described with reference to FIG. In a tenth embodiment shown in FIG. 10, a cooling device is provided in the exhaust gas supply pipe. The same parts as those of the first embodiment shown in FIG. 1 are designated by the same reference numerals, and detailed description thereof will be omitted.

In FIG. 10, a heat exchanger 95 is connected to the exhaust gas supply pipe 23, and the heat exchanger 95 can survive the gas temperature of the exhaust gas of about 100 ° C. at which microalgae die.
It has the ability to drop to 0 ° C.

In FIG. 10, the temperature of the exhaust gas 21 of the thermal power plant is about 100 ° C., and the temperature of this exhaust gas 21 is cooled by the heat exchanger 95 and drops to about 30 ° C. The exhaust gas, which has fallen to around room temperature, is supplied into the reaction tank 24 through the supply pipe 23, CO _{2 is} immobilized by the photosynthetic action of the microalgae 29 held by the carrier 28 in the reaction tank 24, and the treated gas 31 Is discharged as.

According to this embodiment, the temperature of the exhaust gas 21 is 10
By cooling 0 ° C. to 30 ° C. by the heat exchanger 95, the surface of the microalgae 29 in the reaction tank 24 can be maintained at a low temperature, so that high photosynthetic activity can be maintained without dying of the microalgae 29.

The performance, size, number, and
The arrangement and the like are not limited to those shown in FIG. A plurality of heat exchangers 95 and blowers 22 may be arranged in series or in parallel. Further, an example in which the temperature of the exhaust gas 21 is cooled from 100 ° C. to 30 ° C. by the heat exchanger 95 has been shown, but the present invention is not limited to this, and it may be cooled to a viable temperature of about 60 ° C.

Eleventh Embodiment Next, an eleventh embodiment of the present invention will be described with reference to FIG. The eleventh embodiment shown in FIG. 11 uses an open-air reaction tank instead of the closed reaction tank. FIG.
The same parts as those in the first embodiment shown in FIG.

In FIG. 11, the reaction tank 10 is open to the atmosphere.
0 is provided. The microalgae 29 held on the surface of the carrier 28 comes into contact with the atmosphere 101 entering from above the reaction tank 24, and CO ₂ is immobilized by using the supplied water in the liquid medium 25 and the light energy of the light source 30. To be done. Atmosphere 10
1 reduces CO ₂ and then diffuses it into the atmosphere as a processing gas 102.

According to this embodiment, the reaction tank 1 open to the atmosphere is used.
Since 00 is used, power such as a blower is unnecessary,
The operating cost is low.

The structure, size, number and shape of the reaction tank 100 are not limited to those shown in FIG. For example, it is possible to make the reaction tank 100 have a closed structure and forcibly supply the atmosphere 101 into the reaction tank 100 with a blower or the like.

Twelfth Embodiment Next, a twelfth embodiment of the present invention will be described with reference to FIG. In the twelfth embodiment shown in FIG. 12, instead of charging the liquid medium 25, rainwater is stored in an atmosphere-open storage tank 104, and a pipe 106 having a pump 105 in the storage tank 104.
Is connected to one end and the other end of the tube 106 is connected to the reaction tank 100. Others are substantially the same as the eleventh embodiment shown in FIG.

In FIG. 12, the rainwater stored in the storage tank 104 in rainy weather is supplied to the reaction tank 100 through the pipe 106 by driving the pump 105 at appropriate times. The microalgae 29 held on the surface of the carrier 28 in the reaction tank 100 fixes CO ₂ using the light energy of the light source 30 from the supplied water in rainwater and CO ₂ in the atmosphere. The gas that has been immobilized to reduce CO ₂ is treated gas 1
02 is diffused into the atmosphere.

According to this embodiment, the open storage tank 1 is open to the atmosphere.
Since 04 is used, the rainwater 103 is stored in the storage tank 104 when it naturally rains. Reservoir 1 by pump 105
Since the rainwater is supplied into the reaction tank 100 from 04, operation management becomes easy.

In FIG. 12, the storage tank 10 of the atmosphere open type is shown.
Although No. 4 was used, it may be a storage tank that is open in the rain and closed in other weather, or a storage tank buried underground may be used. Although the rainwater was supplied into the reaction tank 100 using the pump 105, other means such as an opening / closing valve or an air lift may be used. Further, not only rainwater but also seawater may be used.

Thirteenth Embodiment Next, a thirteenth embodiment of the present invention will be described with reference to FIG. A thirteenth embodiment shown in FIG. 13 is an opening / closing valve 11 which is opened and closed by a timer 112 on a pipe 27 for introducing the liquid medium 25.
0 is provided, the same parts as those in the first embodiment shown in FIG. 1 are designated by the same reference numerals, and detailed description thereof will be omitted.

In FIG. 13, the timer 112 is set in advance to open the on-off valve 110 once a day for t minutes. When the set time is reached, the on-off valve 110 opens and the liquid medium 25 is supplied to the surface of the microalgae 29 in the reaction tank 24. After t minutes, the on-off valve 110 is closed to stop the supply of the liquid medium 25.

According to this embodiment, the timer 1 is used as the control means.
Since No. 12 is used, operation management is easy with an inexpensive device. Further, since the liquid medium 25 is supplied using the opening / closing valve 110, operation management is easy.

Although the timer 112 is used as the control means, other control means may be used. The liquid medium 25 can also be supplied by using a device other than the on-off valve 110, such as a pump or an air lift.

Fourteenth Embodiment Next, a fourteenth embodiment of the present invention will be described with reference to FIG. In the fourteenth embodiment shown in FIG. 14, a hygrometer 120 is provided in the reaction tank 24, and the opening / closing valve 110 is opened / closed by the control device 121 based on the signal of the hygrometer 120. Others are shown in FIG. This is almost the same as the thirteenth embodiment shown.

In FIG. 14, the hygrometer 1 is installed in the reaction tank 24.
20 is provided, the hygrometer 120 is electrically connected to the control device 121, and the opening / closing valve 110 is connected by the control device 121.
Is controlled.

In FIG. 14, the set value of the hygrometer 120 is previously incorporated in the control device 121 with an upper limit value of 80% (relative humidity) and a lower limit value of 60%. The humidity of the gas phase portion in the reaction tank 24 is measured by the hygrometer 120, and if the lower limit value is less than 60%, the on-off valve 110 is opened and the liquid medium 25 is supplied into the reaction tank 24. When the upper limit value of 80% is exceeded, the on-off valve 110 is closed and the supply of the liquid medium 25 is stopped.

As described above, the value of the hygrometer is always 60 to 80%.
The liquid medium 25 can be always present on the surface of the microalgae 29 to immobilize CO ₂ .

According to this embodiment, since the hygrometer 120 is used, it is easy to measure the amount of water in the gas phase portion in the reaction tank 24, and the operation management becomes easy. Also, the upper and lower limits of ON-OFF
Since the control is performed by the control device 121, the control method is simple and the settings can be easily changed.

It is also possible to use a measuring instrument other than the hygrometer 120 for measuring the amount of water. For example, a dry hygrometer or a water content meter may be used. Further, although the liquid medium 25 is used, water, rainwater, seawater or the like can also be used. Further, the reaction tank 24 has a closed system structure,
It is possible to directly fix CO ₂ in the atmosphere by making it an open system.

Fifteenth Embodiment Next, a fifteenth embodiment of the present invention will be described with reference to FIG. The fifteenth embodiment shown in FIG. 15 is provided with a means for measuring the photosynthetic activity of microalgae, and the other is shown in FIG.
It is almost the same as the fourteenth embodiment shown in FIG. Also supply pipe 23
The first CO ₂ concentration meter 124 and the discharge pipe 32 are respectively provided.
And a second CO ₂ densitometer 126 is provided. Further, the first CO ₂ concentration meter 124 and the second CO ₂ concentration meter 126 are connected to the control device 121, and the control device 121 is electrically connected to the on-off valve 110, respectively.

In FIG. 15, the first CO ₂ concentration meter 12
Based on the value Cin of 4 and the value Cout of the second CO ₂ concentration meter 126, the controller 121 calculates the equation (3). In the formula (3), A1 is the concentration of CO ₂ fixed and the unit is%. First, the lower limit value of A1 is set in the control device 121 in advance. If the lower limit value is further decreased, the photosynthetic activity of the microalgae 29 is decreased and the microalgae 29 may be killed. Here, when Cin is 10%, the lower limit value is 0.1%.

When A1 is below the lower limit value, the on-off valve 11
0 is opened and the liquid medium 25 is fed to the microalgae 29 in the reaction tank 24.
Supply to the surface for a certain period of time. When the liquid medium 25 is supplied, the photosynthetic activity of the microalgae 29 gradually recovers.

A1 = Cin−Cout Formula (3) According to this example, in order to measure the photosynthetic activity of the microalgae 29, the CO ₂ concentration Cin in the exhaust gas 21 was used to calculate the treatment gas 31.
Since the value obtained by subtracting the CO ₂ concentration Cout in the inside, that is, the A1 value is used, the CO ₂ concentration can be directly measured and the C
It becomes possible to measure the O ₂ fixation rate. Moreover, since the CO ₂ concentration in the processing gas 31 is directly measured,
It is also possible to monitor the CO ₂ concentration in the discharged processing gas 31.

The means for measuring the photosynthetic activity of microalgae is not particularly limited. For example, CO _{2 in} light and dark
Method by difference in concentration, method by difference in O ₂ concentration, cell concentration of microalgae 29, for example, dry weight, turbidity, OD, PC
The photosynthetic activity may be measured by the increase in cell concentration of V (cell volume), ATP, DNA and the like.

Although the liquid medium 25 is used as the water source, water, rainwater, seawater or the like can also be used.

[0139]

According to the invention of claim 1, since the photosynthetic reaction is carried out by holding the microalgae containing a small amount of water in the reaction tank, the use of water, the operation of the blower, the concentration of microalgae
The cost of recovery etc. can be reduced, and CO ₂ in the exhaust gas can be immobilized practically and efficiently.

According to the second aspect of the invention, since the volume of the liquid phase in contact with the microalgae held in the reaction tank is set to 1 or less of the liquid gas, the amount of water used can be reduced and the power of the blower and the like can be reduced. it can.

According to the invention described in claim 3, since the carrier for holding the microalgae is arranged on the side wall of the reaction tank, the light irradiation area can be increased, the light utilization efficiency can be improved, and the installation area can be reduced. It becomes possible.

According to the invention described in claim 4, since the carriers are arranged in multiple stages in the light irradiation direction, the light irradiation area can be increased and the installation area of the carriers can be reduced.

According to the invention of claim 5, since the partition wall is provided on the carrier, water can be uniformly supplied to the surface of the microalgae on the carrier, and CO ₂ immobilization can be performed stably. Can be made.

According to the invention of claim 6, since the carrier for holding the microalgae is arranged on the conveying means, water can be uniformly supplied to the surface of the microalgae and the CO ₂ fixing reaction can be stabilized. You can

According to the invention of claim 7, since the combustion ash or the processed product of the combustion ash is used as the material for retaining the microalgae, the microalgae can be retained rapidly and firmly on the surface of the carrier. Also, impurities in exhaust gas can be removed.

According to the invention described in claim 8, since the circulation pipe for circulating the gas in the reaction tank is provided, the stirring strength and the turbulent flow strength in the reaction tank are increased, and therefore CO ₂ and microalgae are increased. The chance of contact with CO ₂ is increased and the CO ₂ fixation rate is improved.

According to the invention of claim 9, since the heat exchanger for cooling the temperature of the exhaust gas to 60 ° C. or less is provided in the exhaust gas supply pipe, the temperature of the exhaust gas is suitable for the CO ₂ fixation reaction of microalgae. It can be lowered to the desired temperature. Therefore, a stable CO ₂ fixation reaction is continued.

According to the tenth aspect of the present invention, CO ₂ in the atmosphere can be reacted, and CO ₂ in the atmosphere can be directly fixed and reduced.

According to the eleventh aspect of the present invention, when the exhaust gas is flowed, the granular carrier holding the microalgae floats in the reaction tank, so that there is a chance of contact between CO _{2 in} the exhaust gas and the microalgae. As a result, the CO ₂ fixation rate is increased, and the installation area of the reaction tank can be reduced.

According to the twelfth aspect of the invention, since the liquids are supplied from the water storage tank for storing rainwater or seawater into the reaction tank for use, natural water can be directly used, and the water usage cost can be reduced. It can be greatly reduced.

According to the thirteenth aspect of the present invention, the amount of water on the surface of the microalgae is measured and the value is used for controlling the supply of liquid medium or the like, or the photosynthetic activity of the microalgae is directly measured to determine the supply amount. Since it is used for control, it is possible to continue the stable and stable CO ₂ fixation operation.

[Brief description of drawings]

FIG. 1 is a schematic configuration diagram showing a first embodiment of a CO ₂ immobilization apparatus using microalgae according to the present invention.

FIG. 2 is a schematic configuration diagram showing a second embodiment of a CO ₂ immobilization device using microalgae according to the present invention.

FIG. 3 is a schematic configuration diagram showing a third embodiment of a CO ₂ immobilization device using microalgae according to the present invention.

FIG. 4 is a schematic configuration diagram showing a fourth embodiment of a CO ₂ immobilization device using microalgae according to the present invention.

FIG. 5 is a schematic configuration diagram showing a fifth embodiment of a CO ₂ immobilization device using microalgae according to the present invention.

FIG. 6 is a schematic configuration diagram showing a sixth embodiment of a CO ₂ immobilization device using microalgae according to the present invention.

FIG. 7 is a schematic configuration diagram showing a seventh embodiment of a CO ₂ immobilization device using microalgae according to the present invention.

FIG. 8 is a schematic configuration diagram showing an eighth embodiment of a CO ₂ immobilization device using microalgae according to the present invention.

FIG. 9 is a schematic configuration diagram showing a ninth embodiment of a CO ₂ immobilization device using microalgae according to the present invention.

FIG. 10 is a schematic configuration diagram showing a tenth embodiment of a CO ₂ immobilization device using microalgae according to the present invention.

FIG. 11 is a schematic configuration diagram showing an eleventh embodiment of a CO ₂ immobilization device using microalgae according to the present invention.

FIG. 12 is a schematic configuration diagram showing a twelfth embodiment of the CO ₂ immobilization apparatus using microalgae according to the present invention.

FIG. 13 is a schematic configuration diagram showing a thirteenth embodiment of the CO ₂ immobilization apparatus using microalgae according to the present invention.

FIG. 14 is a schematic configuration diagram showing a fourteenth embodiment of a CO ₂ immobilization device using microalgae according to the present invention.

FIG. 15 is a schematic configuration diagram showing a fifteenth embodiment of a CO ₂ immobilization device using microalgae according to the present invention.

FIG. 16 is a schematic configuration diagram showing a conventional CO ₂ immobilization method for microalgae.

FIG. 17 is a view showing a time change of the amount of CO ₂ immobilized after once supplying water.

FIG. 18 is a view showing a time change of the CO ₂ immobilization amount when water is regularly supplied.

[Explanation of symbols]

21 Exhaust Gas 22,92 Blower 23 Supply Pipe 24,100 Reaction Tank 25 Liquid Medium 26 On-off Valve 27,106 Pipe 28 Carrier 29 Microalgae 30 Light Source 31 Process Gas 32 Discharge Pipe 33 Liquid Phase 34 Gas Phase 40 First Carrier 41 Second Carrier 42 Third Carrier 70 First Partition 71 Second Partition 72 Third Partition 73 Fourth Partition 81 Motor 82 Belt Conveyor 90 Granular Carrier 91 Combustion Ash 93 Circulation Piping 95 Heat Exchanger 101 Atmosphere 104 Storage Tank 105 Pump 112 Timer 120 Hygrometer 121 Controller 124 First CO ₂ Concentration Meter 125 Second CO ₂ Concentration Meter

─────────────────────────────────────────────────── ─── Continuation of the front page (51) Int.Cl. ⁶ Identification number Office reference number FI technical display location // (C12P 5/02 C12R 1:89)

Claims (13)

[Claims] 1. A closed reaction tank for holding microalgae for immobilizing CO ₂ gas in a state in which the microalgae can be irradiated with light, and an exhaust gas containing CO ₂ gas is supplied into the reaction tank. An apparatus for immobilizing CO ₂ by microalgae, comprising: a means, a means for discharging a processing gas from the reaction tank, and a means for supplying water to the microalgae in the reaction tank. 2. The apparatus for immobilizing CO ₂ by microalgae according to claim 1, wherein the ratio of the water volume to the exhaust gas supply space volume in the reaction tank is 1 or less. 3. The apparatus for immobilizing CO ₂ by microalgae according to claim 1, wherein microalgae are retained on the side wall in the reaction tank. 4. The microalgae-containing CO ₂ according to claim 1, wherein the microalgae are held by a plate-shaped carrier in the reaction tank, and the carriers are arranged in multiple horizontal directions in the reaction tank.
Immobilization device. 5. The microalgae according to claim 1, wherein the microalgae are held by a plate-shaped carrier in the reaction tank, the carriers are arranged at an angle, and partition walls are provided on the carrier. CO ₂ fixation device. 6. A microalgae is held by a carrier in the reaction tank, and the carrier is arranged on a carrying means.
_{2. The} CO ₂ immobilization device for microalgae according to claim 1, further comprising a drive device for driving the transportation means. 7. The microalgae CO ₂ according to claim 1, characterized in that the microalgae is held in contact with the material obtained by processing the combustion ash or the combustion charcoal in the reaction tank.
Immobilization device. 8. The CO ₂ immobilization device for microalgae according to claim 1, wherein a circulation pipe is provided in the reaction tank to circulate the gas in the exhaust gas supply space of the reaction tank. 9. The exhaust gas temperature is set to 60 ° C. in the exhaust gas supply means.
The CO ₂ immobilization device for microalgae according to claim 1, further comprising a cooling device for cooling. 10. A hermetically sealed reaction tank in which light is radiated, and a CO 2 which floats in a gas phase in the hermetically sealed reaction tank,
₂ a granular carrier that holds microalgae for immobilizing the gas, a means for supplying an exhaust gas containing CO ₂ gas into the gas phase in the reaction tank, and a means for discharging the processing gas from the reaction tank, A CO ₂ immobilization device using microalgae characterized by being provided. 11. An atmosphere open type reaction tank for holding microalgae for immobilizing CO ₂ gas in a state in which the microalgae can be irradiated with light, and an exhaust gas containing CO ₂ gas is supplied into the reaction tank. A CO ₂ immobilization device for microalgae, comprising: a means for discharging the treated gas from the reaction tank; and a means for supplying water to the microalgae in the reaction tank. 12. The means for supplying water is connected to a water tank for rainwater or seawater.
A CO ₂ immobilization device using the described microalgae. 13. A closed reaction tank for holding microalgae for immobilizing CO ₂ gas in a state in which the microalgae can be irradiated with light, and an exhaust gas containing CO ₂ gas is supplied into the reaction tank. Means, means for discharging processing gas from the reaction tank, means for supplying water to the microalgae in the reaction tank, means for measuring water in the reaction tank, and means for measuring photosynthetic activity of microalgae Among these, at least one measuring means, and means for controlling the supply of water to the microalgae based on the measurement value from this measuring means, a CO ₂ immobilization device for microalgae characterized by the following: