JP2017109198A - Carbon dioxide absorbing material, pellet and filter - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide, at low cost, carbon dioxide absorbing material that absorbs, from a gas comprising moisture and carbon dioxide, the carbon dioxide included in the gas.SOLUTION: A carbon dioxide absorbing material (10) absorbs, from a gas comprising moisture and carbon dioxide, the carbon dioxide included in the gas. The carbon dioxide absorbing material (10) comprises sodium ferrite as the main component and further comprises potassium carbonate.SELECTED DRAWING: Figure 1

Description

The present invention relates to a carbon dioxide absorbent that absorbs carbon dioxide (CO ₂ ) contained in a gas.

  In recent years, the Lawrence Berkeley National Laboratory in the US has reported that the ability to think decreases when the carbon dioxide concentration exceeds 2500 ppm. Thus, when the carbon dioxide concentration in the air exceeds a specific concentration, the human body is adversely affected. For this reason, it is necessary to prevent an increase in the concentration of carbon dioxide in the air. Some analytical instruments also require the removal of carbon dioxide from the captured air. Based on these points, techniques for removing carbon dioxide contained in gas have been developed. Such a technique is disclosed in Patent Documents 1 to 3, for example.

  Patent Document 1 discloses a technique for removing carbon dioxide by adsorbing carbon dioxide in a gas stream to zeolite. Patent Document 2 discloses a technique for removing carbon dioxide in combustion exhaust gas by bringing the combustion exhaust gas into contact with an aqueous amine solution. Patent Document 3 discloses a carbon dioxide absorbent containing lithium silicate as a main component, containing a predetermined amount of moisture.

Japanese Patent Laid-Open No. 11-253736 (published on September 21, 1999) JP-A-8-252430 (released on October 1, 1996) JP 2003-126688 A (released May 7, 2003)

  However, the zeolite disclosed in Patent Document 1 has hydrophilicity. For this reason, when zeolite separates and adsorbs carbon dioxide from a gas containing moisture and carbon dioxide, the zeolite preferentially adsorbs moisture. Therefore, there has been a problem that the ability of the zeolite to separate and adsorb carbon dioxide is remarkably lowered. Moreover, in the technique of patent document 1, since the dehumidification mechanism was needed in order to prevent a zeolite from adsorb | sucking a water | moisture content, there existed a problem that the cost for providing the said dehumidification mechanism was essential.

  Moreover, the amine aqueous solution currently disclosed by patent document 2 is aqueous solution which has a density | concentration more than fixed. For this reason, when carbon dioxide is separated and absorbed from the gas, unless the aqueous amine solution is always regenerated, the concentration of the aqueous amine solution is lowered, and the carbon dioxide absorption characteristic is lowered.

  That is, if the aqueous amine solution is not treated so as to maintain a concentration above a certain level, there is a problem that the concentration of the aqueous amine solution decreases and carbon dioxide cannot be absorbed. Further, the technique of Patent Document 2 requires a complicated (large-scale) absorption / regeneration mechanism for adjusting the concentration of the aqueous amine solution so that carbon dioxide can be absorbed again. There was a problem that the cost for providing was essential.

  Further, the carbon dioxide absorbent disclosed in Patent Document 3 can absorb carbon dioxide (in other words, carbon dioxide) from a gas containing moisture and carbon dioxide at room temperature. However, since lithium is an expensive material, there has been a problem that the cost of the carbon dioxide absorbent increases.

  As described above, the techniques of Patent Documents 1 to 3 have a problem that a carbon dioxide absorbent that absorbs carbon dioxide from a gas containing moisture and carbon dioxide cannot be realized at low cost.

  This invention is made | formed in view of said problem, The objective is to implement | achieve the carbon dioxide absorber which absorbs a carbon dioxide from the gas containing a water | moisture content and a carbon dioxide at low cost. .

  In order to solve the above problems, a carbon dioxide absorbent according to one embodiment of the present invention is a carbon dioxide absorbent that absorbs carbon dioxide contained in a gas from a gas containing moisture and carbon dioxide. In addition, it contains sodium ferrite as a main component and further contains potassium carbonate.

  According to the carbon dioxide absorbent according to one aspect of the present invention, there is an effect that a carbon dioxide absorbent that absorbs carbon dioxide from a gas containing moisture and carbon dioxide can be realized at low cost.

It is a figure which shows an example of the measurement mechanism which measures the density | concentration of the carbon dioxide in the container in Embodiment 1 of this invention. It is a figure which shows the measurement result of the absorption characteristic of a carbon dioxide about each of the carbon dioxide absorber as an Example of this invention, and the carbon dioxide absorber as a comparative example. It is a figure which shows the measurement result of the absorption characteristic of a carbon dioxide about each of the carbon dioxide absorber and potassium carbonate as a comparative example of this invention. It is a figure which shows the measurement result of the relationship between the addition amount of potassium carbonate, and the absorption rate of a carbon dioxide in the carbon dioxide absorber which concerns on Embodiment 1 of this invention. (A) is a figure which shows an example of the filter which concerns on Embodiment 2 of this invention, (b) is an enlarged view of the principal part of the filter in (a).

Embodiment 1
Hereinafter, Embodiment 1 of the present invention will be described with reference to FIGS. In the present embodiment, a carbon dioxide absorbent 10 that absorbs carbon dioxide from a gas containing moisture and carbon dioxide will be described.

(Carbon dioxide absorbent 10)
FIG. 1 is a diagram illustrating an example of a measurement mechanism that measures the concentration of carbon dioxide in the container 1. Specifically, the measurement mechanism shown in FIG. 1 measures the amount of carbon dioxide absorbed by the carbon dioxide absorbent 10. Hereinafter, the carbon dioxide absorbent 10 will be described first. Members other than the carbon dioxide absorbent 10 will be described later.

  The carbon dioxide absorbent 10 can absorb carbon dioxide contained in the gas. Specifically, the carbon dioxide absorbent 10 separates at least a part of carbon dioxide from a gas containing moisture (that is, water vapor) and carbon dioxide (that is, carbon dioxide gas), and absorbs the carbon dioxide. Is possible.

The carbon dioxide absorbent 10 contains sodium ferrite (NaFeO ₂ ) as a main component. In addition, the carbon dioxide absorbent 10 contains potassium carbonate (K ₂ CO ₃ ).

  Here, sodium ferrite being the main component of the carbon dioxide absorbent 10 means that the ratio of sodium ferrite to the total amount of substances contained in the carbon dioxide absorbent 10 is sufficiently large. As an example, the ratio of sodium ferrite with respect to all the substances contained in the carbon dioxide absorbent 10 is 80% or more.

  Furthermore, as described later, the inventors of the present application have newly found a suitable numerical range of the molar ratio of potassium carbonate to sodium ferrite in the carbon dioxide absorbent 10 as a result of intensive studies.

  Specifically, the molar ratio of potassium carbonate to sodium ferrite in the carbon dioxide absorbent 10 is preferably more than 0 and 0.2 or less. In other words, in the carbon dioxide absorbent 10, the amount of potassium carbonate added to sodium ferrite is preferably more than 0 mol% and not more than 20 mol%.

(Examples and Comparative Examples)
Then, in order to show the effect of the carbon dioxide absorbent 10 specifically, the carbon dioxide absorbent as an example of the carbon dioxide absorbent 10 of the present embodiment will be described. A carbon dioxide absorbent as a comparative example is also described.

  Hereinafter, in order to distinguish each carbon dioxide absorbent, (i) the carbon dioxide absorbent of the example is referred to as carbon dioxide absorbent A, and (ii) the carbon dioxide absorbent of the comparative example is referred to as carbon dioxide absorbent B. I will do it.

  The carbon dioxide absorbent B is the same as the carbon dioxide absorbent A in that it contains sodium ferrite as a main component. As an example, the ratio of sodium ferrite with respect to all the substances contained in the carbon dioxide absorbent B is 80% or more.

  However, the carbon dioxide absorbent B does not contain potassium carbonate. In this respect, the carbon dioxide absorbent B is different from the carbon dioxide absorbent A.

(Method for producing carbon dioxide absorbent B)
First, an example of the manufacturing method of the carbon dioxide absorbent B will be described. First, for example, sodium nitrate (NaNO ₃ ) as a Na source and iron oxide (Fe ₂ O ₃ ) as a Fe source were sufficiently mixed in an organic solvent using a mortar at a molar ratio of 2: 1. . Then, after removing the organic solvent with an evaporator, heat treatment was performed at a temperature of 550 ° C. to 600 ° C. in the atmosphere.

  And the powder (powder) of the carbon dioxide absorber B was obtained by grind | pulverizing the powder obtained in the mortar by said manufacturing process.

The carbon dioxide absorbent B synthesized in this way is, for example, sodium ferrite (α-NaFeO ₂ ) having a layered structure, and can absorb carbon dioxide from a gas containing moisture and carbon dioxide.

(Method for producing carbon dioxide absorbent A)
Subsequently, the carbon dioxide absorbent A can be produced by adding a predetermined amount of potassium carbonate to the carbon dioxide absorbent B obtained by the above-described production method. For example, in this example, the potassium carbonate powder was added to the carbon dioxide absorbent B powder so that the amount of potassium carbonate added to sodium ferrite was 5 mol%.

  And the powder (powder) of the carbon dioxide absorbent A was obtained by mixing the powder of the carbon dioxide absorbent B and the powder of potassium carbonate in a mortar.

(Carbon dioxide absorption characteristics of carbon dioxide absorbents A and B)
Subsequently, the carbon dioxide absorption characteristics of the carbon dioxide absorbents A and B will be described. First, referring to FIG. 1 again, the configuration of a measurement mechanism for measuring the carbon dioxide absorption characteristics will be described.

(Configuration of measurement mechanism)
As shown in FIG. 1, the measurement mechanism includes a container 1, a concentration measuring device 2, and a dish 3. The said measurement mechanism is an example of the mechanism which measures the carbon dioxide absorption characteristic of a carbon dioxide absorber. More specifically, the measurement mechanism measures the amount of carbon dioxide absorbed in the carbon dioxide absorbent by measuring the concentration of carbon dioxide in the gas contained in the container 1.

  The container 1 can be filled with a gas containing moisture and carbon dioxide to create a measurement environment therein. A door (not shown) is provided on the front surface of the container 1. In the present embodiment, the material of the container 1 is acrylic, but the material of the container 1 is not particularly limited as long as the measurement environment described above can be provided.

  The concentration measuring device 2 measures the concentration of carbon dioxide in the gas contained in the container 1 in a sealed state with the door closed, and is built in the container 1. The dish 3 is for placing various carbon dioxide absorbing materials (for example, the carbon dioxide absorbing material 10), and is placed inside the container 1. The above-mentioned carbon dioxide absorbent A or B may be placed on the dish 3.

  The measuring method of the carbon dioxide absorption characteristic of the carbon dioxide absorbent A is as follows. First, the container 1 made of acrylic and having an internal volume of 12 liters was placed in an atmosphere having a temperature of 23 ° C. and a humidity of 55% RH (Relative Humidity), and the interior of the container 1 was made the same atmosphere as the atmosphere.

  Thereafter, 0.1 gram of carbon dioxide absorbent A in powder form was placed in the dish 3, and the dish 3 was placed inside the container 1. Then, the door of the container 1 was closed and the inside of the container 1 was sealed. In this state, the concentration measuring device 2 measured the concentration of carbon dioxide contained in the container 1 over time. Thus, the carbon dioxide absorption characteristics of the carbon dioxide absorbent A were measured.

  In addition, for the comparison experiment, a container similar to the above container 1 was prepared, and 0.1 gram of the carbon dioxide absorbent B in the form of powder was placed in a dish in the container under the same measurement conditions. . Then, in the same manner as described above, the carbon dioxide absorption characteristics of the carbon dioxide absorbent B placed in the container were measured.

  Hereinafter, for convenience of explanation, a container in which (i) the carbon dioxide absorbent A is placed is referred to as a container A, and (ii) a container in which the carbon dioxide absorbent B is placed is referred to as a container B.

(Measurement result)
FIG. 2 is a graph showing the above measurement results in the container A and the container B. That is, FIG. 2 is a graph showing the transition of the concentration of carbon dioxide with time in the containers A and B. Note that FIG. 2 may be understood to be a graph showing the measurement results of the absorption characteristics of carbon dioxide for each of the carbon dioxide absorbents A and B.

  According to FIG. 2, it was confirmed that the concentration of carbon dioxide in the container A was lower than the concentration of carbon dioxide in the container B for at least 40 hours from the measurement start time. That is, the carbon dioxide absorbent A (carbon dioxide absorbent containing potassium carbonate) absorbs more carbon dioxide within a predetermined time than the carbon dioxide absorbent B (carbon dioxide absorbent containing no potassium carbonate). It was confirmed that

  That is, from the measurement result of FIG. 2, it was confirmed that the carbon dioxide absorbent A achieved a faster carbon dioxide absorption rate than the carbon dioxide absorbent B.

(Carbon dioxide absorption characteristics of carbon dioxide absorbent B and potassium carbonate)
As described above, the carbon dioxide absorbent A can be produced by adding potassium carbonate to the carbon dioxide absorbent B. That is, potassium carbonate is an additive for producing the carbon dioxide absorbent A.

  Next, the carbon dioxide absorption characteristics of the carbon dioxide absorbent B and potassium carbonate will be described with reference to FIG. FIG. 3 is a measurement result of carbon dioxide absorption characteristics for each of the carbon dioxide absorbent B and potassium carbonate in the case of using the measurement method described above (more specifically, the concentration of carbon dioxide over time) FIG.

  In FIG. 3, the carbon dioxide concentration at the start of measurement was 0 ppm (reference concentration), and the amount of change from the reference concentration was the carbon dioxide concentration at each time. In this measurement, the sample weight of the carbon dioxide absorbent B and potassium carbonate was 0.04 g, the temperature was 20 ° C., the humidity was 53% RH, and the carbon dioxide concentration at the start of measurement was 400 to 500 ppm.

  According to FIG. 3, the concentration of carbon dioxide in the container containing the carbon dioxide absorbent B is lower than the concentration of carbon dioxide in the container containing potassium carbonate for at least 20 hours from the start of measurement. confirmed.

  That is, it was confirmed that the carbon dioxide absorbent B (carbon dioxide absorbent not containing potassium carbonate) absorbs more carbon dioxide within a predetermined time than potassium carbonate. That is, it was confirmed that the carbon dioxide absorbent B has a higher carbon dioxide absorption rate than potassium carbonate.

  Therefore, from the measurement result of FIG. 3, it is assumed that the carbon dioxide absorbent A has a slower carbon dioxide absorption rate than the carbon dioxide absorbent B. The carbon dioxide absorbent A is created by adding potassium carbonate (a carbon dioxide absorbent having a slower carbon dioxide absorption rate than the carbon dioxide absorbent B) to the carbon dioxide absorbent B. is there.

  However, as is clear from the measurement results of FIG. 2 described above, the carbon dioxide absorbent A achieved a faster carbon dioxide absorption rate than the carbon dioxide absorbent B.

(A study on the mechanism of carbon dioxide absorption rate increase)
As described above, the inventor of the present application newly found that the carbon dioxide absorption material A can be used to increase the absorption rate of carbon dioxide from a gas containing moisture and carbon dioxide.

  The mechanism (principle) of increasing the carbon dioxide absorption rate in the carbon dioxide absorbent by adding potassium carbonate to the carbon dioxide absorbent containing sodium ferrite as a main component has not been elucidated at this time. However, the inventors of the present application infer about an example of this mechanism as follows.

  (Inference): By adding potassium carbonate having deliquescence to sodium ferrite, which is a base material (main component) of a carbon dioxide absorbent, moisture attached to the surface of sodium ferrite becomes alkaline. Then, as the moisture becomes alkaline, a part of the surface of sodium ferrite is dissolved. As a result, the absorption reaction of carbon dioxide in sodium ferrite is promoted.

(Effect of carbon dioxide absorbent 10)
As described above, the carbon dioxide absorbent 10 (carbon dioxide absorbent A) of the present embodiment can efficiently absorb carbon dioxide from a gas containing moisture and carbon dioxide.

  In addition, as described above, the carbon dioxide absorbent 10 contains sodium ferrite, which is a low-cost material, as a main component. Therefore, the carbon dioxide absorbent 10 can be manufactured at a lower cost than a carbon dioxide absorbent containing an expensive material such as lithium silicate as a main component.

  Moreover, the carbon dioxide absorbent 10 may not contain zeolite as a component. For this reason, the carbon dioxide absorbent 10 can be used without requiring a dehumidifying mechanism for preventing the adsorption of moisture by zeolite. Further, when the carbon dioxide absorbent 10 is used, an absorption regeneration mechanism for adjusting the concentration of the aqueous amine solution is not necessary.

  Therefore, according to the carbon dioxide absorbent 10, the cost of providing special equipment or a mechanism for maintaining the function of the carbon dioxide absorbent can be reduced. Further, it is not necessary to secure a space for installing the equipment or mechanism.

  As described above, according to the carbon dioxide absorbent 10, there is an effect that a carbon dioxide absorbent that absorbs carbon dioxide from a gas containing moisture and carbon dioxide can be realized at low cost.

(Preferable addition amount of potassium carbonate in carbon dioxide absorbent 10)
Then, with reference to FIG. 4, the suitable addition amount of the potassium carbonate in the carbon dioxide absorber 10 is demonstrated. FIG. 4 is a table showing the measurement results of the relationship between the amount of potassium carbonate added and the carbon dioxide absorption ratio (CO ₂ absorption ratio) in the carbon dioxide absorbent 10.

  As described below, the molar ratio of potassium carbonate to sodium ferrite in the carbon dioxide absorbent 10 is preferably more than 0 and 0.2 or less. The inventor of the present application newly found that the carbon dioxide absorption efficiency in the carbon dioxide absorbent 10 is particularly high when the molar ratio relationship is satisfied.

  As shown in FIG. 4, the inventor of the present application changes the addition amount of potassium carbonate in the carbon dioxide absorbent 10 in various ways in order to find a suitable addition amount of potassium carbonate in the carbon dioxide absorbent 10. The amount of carbon dioxide absorbed by the carbon dioxide absorbent (and the carbon dioxide absorption ratio) was measured.

  In the measurement, the sample weight of the carbon dioxide absorbent 10 was 0.03 to 0.04 g, the temperature was 18 to 19 ° C., and the humidity was 38 to 50% RH. Here, when the absorption ratio of carbon dioxide is expressed as P, P is calculated by the following equation (1).

P = X / Y (1)
X is the amount of carbon dioxide absorbed by the carbon dioxide absorbent 10 to which a predetermined amount of potassium carbonate has been added after the elapse of a predetermined time from the start of measurement.

  Y is based on a carbon dioxide absorbent containing sodium ferrite as a main component but not containing potassium carbonate (in other words, the above-mentioned carbon dioxide absorbent B) after a predetermined time has elapsed from the start of measurement. This is the amount of carbon dioxide absorbed.

  As shown in FIG. 4, in the measurement, the predetermined time is “10 hours”. Further, a predetermined amount of potassium carbonate (addition amount of potassium carbonate) was set to three types of “1.6 mol%”, “10 mol%”, and “20 mol%”. It was confirmed that P ≧ 1 at any of the three addition amounts.

  Thus, the inventor of the present application sets the amount of potassium carbonate added to sodium ferrite to be greater than 0 mol% and not more than 20 mol% (in other words, the molar ratio of potassium carbonate to sodium ferrite is greater than 0 and 0 It was found experimentally that the carbon dioxide absorption efficiency in the carbon dioxide absorbent 10 can be improved.

(Application field of carbon dioxide absorbent 10)
The carbon dioxide absorbent 10 can be used in an environment where carbon dioxide needs to be absorbed from a gas containing moisture and carbon dioxide (for example, an environment where carbon dioxide is continuously generated). That is, the carbon dioxide absorbent 10 can be used to remove carbon dioxide emitted by living organisms such as humans in a human living space where air exists.

  From this point of view, the carbon dioxide absorbent 10 can be suitably used in electronic devices such as an air purifier, a humidifier, and a dehumidifier used in the living space. As described above, the carbon dioxide absorbent 10 functions effectively in an environment where moisture is contained in the gas. Even in view of this point, it can be said that the carbon dioxide absorbent 10 can be suitably used in the electronic apparatus.

  In addition, the carbon dioxide absorbent 10 can be used in a spacecraft or a submarine having a space sealed from the external environment. Further, the carbon dioxide absorbent 10 can be incorporated in an analytical instrument that needs to remove carbon dioxide from the taken-in air, or can be used in a room where the analytical instrument is installed. Furthermore, the carbon dioxide absorbent 10 can also be used in an environment (for example, a thermal power plant) in which fossil fuel that generates carbon dioxide is combusted.

  The carbon dioxide absorbent 10 may be used in the above various environments in a form applied to the pellet 20 or the filter 30 of the second embodiment described below.

[Embodiment 2]
The second embodiment of the present invention will be described below with reference to FIG. For convenience of explanation, members having the same functions as those described in the above embodiment are denoted by the same reference numerals and description thereof is omitted.

  (A) of FIG. 5 is a figure which shows an example of the filter 30 in this embodiment. FIG. 5B is an enlarged view of the main part of the filter 30 in FIG. As shown below, the pellet 30 is built in the filter 30.

(Pellets 20)
The pellet 20 includes the carbon dioxide absorbent 10 of the first embodiment. Therefore, the pellet 20 can suitably absorb carbon dioxide from a gas containing moisture and carbon dioxide. Also, the pellet 20 can be manufactured at a low cost.

  In addition, the pellet 20 is granulated by hardening the carbon dioxide absorbent 10 which is powder. Therefore, the pellet 20 is a granulated material larger than the carbon dioxide absorbent 10.

  As shown in FIG. 5B, the pellet 20 in the present embodiment is granulated by forming a powder carbon dioxide absorbent 10 into a substantially cylindrical shape. However, the shape of the pellet 20 is not limited to a substantially cylindrical shape. The pellet 20 may be formed into various shapes such as a substantially spherical shape or a rectangular parallelepiped.

  The shape and size (particle size) of the pellet 20 are such that the pressure loss can be reduced when the pellet 20 is incorporated in the filter 30 in consideration of being incorporated in the filter 30 described later. It is preferable. In this case, the size of the pellet 20 is preferably about several mm to several tens mm, for example. Here, the size of the pellet 20 is the minimum value of the diameter of a virtual sphere that contains the pellet 20.

(Method for producing pellet 20)
Then, an example of the preparation method of the pellet 20 is demonstrated.

  First, the carbon dioxide absorbent 10 produced by the production method described in Embodiment 1 and a binder are mixed (binder mixing step). Thereafter, the mixture of the carbon dioxide absorbent 10 and the binder is inserted into a predetermined mold and sintered at a predetermined temperature (sintering step).

  Thereby, the pellet 20 containing the carbon dioxide absorber 10 which is powder is produced. Moreover, the pellet 20 is produced as a granulated material larger than the carbon dioxide absorbent 10.

(Filter 30)
The filter 30 is a filter that absorbs carbon dioxide from a gas containing moisture and carbon dioxide. The filter 30 may be a particle-filled filter capable of filling the carbon dioxide absorbent 10 as powder in the filter 30 in order to absorb carbon dioxide.

  However, as shown in FIGS. 5A and 5B, in this embodiment, the filter 30 incorporates the above-described pellet 20 in place of the carbon dioxide absorbent 10 as a powder. Hereinafter, a specific configuration of the filter 30 will be described.

  The filter 30 includes a pellet 20 and a dustproof filter 35 inside the filter 30. The filter 30 has two openings (not shown). An insertion tube 36 and a discharge tube 37 are connected to each opening of the filter 30.

  The insertion tube 36 is a tube through which a gas containing moisture and carbon dioxide passes. The insertion tube 36 is provided to insert the gas into the filter 30. The exhaust pipe 37 is a pipe through which the gas after a part of the carbon dioxide is absorbed (removed) by the filter 30 passes. The discharge pipe 37 is provided to discharge the gas to the outside of the filter 30.

  The dustproof filter 35 is provided to prevent foreign substances such as dust from entering the filter 30 from the insertion tube 36 and the discharge tube 37. The dustproof filter 35 is disposed inside the filter 30 so as to cover at least two openings of the filter 30.

  The dustproof filter 35 covering the opening on the insertion tube 36 side uniformly disperses the gas inserted into the filter 30 from the insertion tube 36 into the filter 30, and the pellet 20 leaks from the opening to the insertion tube 36. It has a function to prevent this. The dust filter 35 that covers the opening on the discharge pipe 37 side has a function of preventing the pellet 20 from leaking from the opening to the discharge pipe 37.

  In addition, pellets 20 are spread inside the filter 30. A gas containing moisture and carbon dioxide passes through the insertion tube 36 and is inserted into the filter 30. The carbon dioxide in the gas is absorbed by the pellet 20 inside the filter 30. Subsequently, the gas after the carbon dioxide is absorbed is discharged from the discharge pipe 37 to the outside of the filter 30.

  Thus, according to the filter 30, carbon dioxide can be removed from the gas containing moisture and carbon dioxide, and the gas after the carbon dioxide has been removed can be supplied to the external space of the filter 30.

(Effect of pellet 20)
As described above, the pellet 20 includes the carbon dioxide absorbent 10 of the first embodiment. Therefore, the pellet 20 can also efficiently absorb carbon dioxide from a gas containing moisture and carbon dioxide over a long period of time. Also, the pellet 20 can absorb carbon dioxide from the gas at a low cost.

  Furthermore, the pellet 20 is a granulated material larger than the carbon dioxide absorbent 10 formed by sintering the carbon dioxide absorbent 10 which is powder. For this reason, according to the pellet 20, there exists an effect that the versatility of the carbon dioxide absorber 10 which is powder can be improved.

(Effect of filter 30)
Next, the effect of the filter 30 will be described. As described above, the filter 30 incorporates the pellet 20 including the carbon dioxide absorbent 10.

  By the way, even when the carbon dioxide absorbent 10 that is powder is spread as it is inside the filter 30, the gas from the gas (gas containing water and carbon dioxide) inserted from the insertion tube 36 in the filter 30 is oxidized. It is possible to absorb carbon.

  However, when the carbon dioxide absorbent 10 is a powder (particularly when the particle diameter of the powder is on the order of μm), if the powder is built in the filter 30, the gap between the powders becomes small. In addition, the pressure loss inside the filter 30 increases. For this reason, clogging occurs inside the filter 30.

  When clogging occurs inside the filter 30, the gas inserted into the filter 30 from the insertion tube 36 cannot pass through the filter 30. For this reason, there is a possibility that carbon dioxide contained in the gas cannot be absorbed by the entire powdery carbon dioxide absorbent 10 incorporated in the filter 30.

  On the other hand, as described above, the pellet 20 of the present embodiment is a granulated material larger than the carbon dioxide absorbent 10 that is a powder. For this reason, the gap between the pellets 20 when the pellets 20 are built in the filter 30 is larger than the gap between the carbon dioxide absorbents 10 when the filter 30 contains the powdered carbon dioxide absorbent 10.

  Therefore, by incorporating the pellet 20 in the filter 30, the pressure loss inside the filter 30 can be reduced. For this reason, the gas inserted from the insertion tube 36 into the filter 30 can easily pass through the filter 30.

  Therefore, carbon dioxide contained in the gas can be absorbed by the whole pellet 20 built in the filter 30 (in other words, the whole carbon dioxide absorbent 10). Thus, by incorporating the pellet 20 in the filter 30, it becomes possible to efficiently absorb carbon dioxide contained in the gas inserted into the filter 30.

  As described above, in this embodiment, by incorporating the pellet 20 containing the carbon dioxide absorbent 10 in the filter 30, the pressure loss is increased, and thus it is difficult to apply the powder directly to the filter 30. This carbon dioxide absorbent 10 can be applied to the filter 30.

  Thus, the filter 30 also has an effect that carbon dioxide can be efficiently absorbed at low cost from a gas containing water and carbon dioxide.

[Summary]
A carbon dioxide absorbent (10) according to aspect 1 of the present invention is a carbon dioxide absorbent that absorbs carbon dioxide contained in the gas from a gas containing moisture and carbon dioxide. It is contained as a component and further contains potassium carbonate.

  According to said structure, the carbon dioxide absorber contains sodium ferrite as a main component, and further contains potassium carbonate. Therefore, as described above, the carbon dioxide absorbent can efficiently absorb carbon dioxide from a gas containing moisture and carbon dioxide.

  In addition, since the carbon dioxide absorber contains sodium ferrite, which is a low-cost material, as a main component, it can be manufactured at low cost. Moreover, since the special installation or mechanism for hold | maintaining the function of a carbon dioxide absorber is unnecessary, the cost which provides these installations or mechanisms can also be reduced.

  As mentioned above, according to said structure, there exists an effect that it becomes possible to implement | achieve the carbon dioxide absorber which absorbs a carbon dioxide from the gas containing a water | moisture content and a carbon dioxide at low cost.

  In the carbon dioxide absorbent according to aspect 2 of the present invention, in the above aspect 1, the molar ratio of the potassium carbonate to the sodium ferrite is preferably greater than 0 and not greater than 0.2.

  According to said structure, there exists an effect that it becomes possible to further improve the absorption efficiency of the carbon dioxide in a carbon dioxide absorber.

  It is preferable that the pellet (20) which concerns on aspect 3 of this invention contains the carbon dioxide absorber which concerns on the said aspect 1 or 2.

  According to said structure, the pellet containing the carbon dioxide absorber which concerns on 1 aspect of this invention is realizable. Even when the carbon dioxide absorbent is formed as a powder, the versatility of the carbon dioxide absorbent can be improved.

  The filter (30) according to aspect 4 of the present invention preferably includes the pellet according to aspect 3 described above.

  According to said structure, the pellet granulated larger than the powdered carbon dioxide absorber can be incorporated in a filter. Therefore, since the pressure loss in the filter is reduced, the gas inserted into the filter can easily pass through the filter. Therefore, there is an effect that carbon dioxide contained in the gas can be efficiently absorbed.

[Additional Notes]
The present invention is not limited to the above-described embodiments, and various modifications are possible within the scope shown in the claims, and embodiments obtained by appropriately combining technical means disclosed in different embodiments. Is also included in the technical scope of the present invention. Furthermore, a new technical feature can be formed by combining the technical means disclosed in each embodiment.

[Another expression of the present invention]
The present invention can also be expressed as follows.

  That is, the carbon dioxide absorbent according to one embodiment of the present invention is a carbon dioxide absorbent that absorbs carbon dioxide from a gas containing moisture and carbon dioxide, the main component is sodium ferrite, and potassium carbonate is include.

  Further, the carbon dioxide absorbent according to one embodiment of the present invention is a carbon dioxide absorbent that absorbs carbon dioxide from a gas containing moisture and carbon dioxide, the main component is sodium ferrite, and potassium carbonate is The molar ratio of the potassium carbonate to the sodium ferrite is greater than 0 and less than or equal to 0.2.

  Moreover, the pellet which concerns on 1 aspect of this invention is a pellet which absorbs the carbon dioxide contained in gas, Comprising: The carbon dioxide absorber which concerns on 1 aspect of this invention is included.

  In addition, a filter according to one embodiment of the present invention is a filter that absorbs carbon dioxide contained in a gas, and includes a pellet according to one embodiment of the present invention.

10 Carbon dioxide absorbent 20 Pellets 30 Filter

Claims (4)

From a gas containing moisture and carbon dioxide, a carbon dioxide absorbent that absorbs carbon dioxide contained in the gas,
Contains sodium ferrite as the main component,
A carbon dioxide absorbent characterized by further containing potassium carbonate.   The carbon dioxide absorbent according to claim 1, wherein a molar ratio of the potassium carbonate to the sodium ferrite is more than 0 and 0.2 or less.   A pellet comprising the carbon dioxide absorbent according to claim 1.   A filter containing the pellet according to claim 3.

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