WO2018061285A1

WO2018061285A1 - Carbon dioxide absorption device and electronic apparatus

Info

Publication number: WO2018061285A1
Application number: PCT/JP2017/017564
Authority: WO
Inventors: 峻之中; 貴洋土江; 健太郎岸良; 博久山田; 郁夫柳瀬
Original assignee: シャープ株式会社; 国立大学法人埼玉大学
Priority date: 2016-09-30
Filing date: 2017-05-09
Publication date: 2018-04-05
Also published as: JP2019205952A

Abstract

The present invention controls the carbon dioxide (CO₂) absorption amount of a carbon dioxide absorber by means of a simple configuration. In a carbon dioxide absorption device (1), a carbon dioxide absorber (10) includes tetravalent lithium silicate. The carbon dioxide absorption device (1) is further provided with: a holding part (11) that holds the carbon dioxide absorber (10) and water moisture, and supplies at least a portion of the held water moisture to the carbon dioxide absorber (10); a water moisture supply part (12) that supplies the water moisture to the holding part (11); and an addition amount setting unit (132) that controls the operation of the water moisture supply part (12).

Description

Carbon dioxide absorber and electronic device

The following disclosure relates to a carbon dioxide absorption device including a carbon dioxide absorbent that absorbs carbon dioxide (CO ₂ ) contained in a gas.

In recent years, the Lawrence Berkeley National Laboratory in the United States has reported that the thinking ability decreases when the CO ₂ concentration exceeds 2500 ppm. Thus, when the CO ₂ concentration in the air becomes more specific concentrations, adversely affects the human body. For this reason, it is necessary to prevent an increase in the CO ₂ concentration in the air. Some analytical instruments also require the removal of CO ₂ from the captured air. Based on these points, techniques for removing CO ₂ contained in gas have been developed. Such techniques are disclosed in, for example, Patent Documents 1 to 3.

Patent Document 1 discloses a technique for removing CO ₂ by adsorbing CO ₂ in a gas stream to zeolite. Patent Document 2 discloses a technique for removing CO _{2 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 Publication “Japanese Patent Laid-Open No. 11-253736 (published on September 21, 1999)” Japanese Patent Publication “Japanese Patent Laid-Open No. 8-252430 (published on October 1, 1996)” Japanese Patent Publication “Japanese Patent Laid-Open No. 2005-13952 (published on January 20, 2005)”

However, the zeolite disclosed in Patent Document 1 has hydrophilicity. For this reason, when zeolite separates and adsorbs CO ₂ from a gas containing moisture and CO ₂ , the zeolite preferentially adsorbs moisture. Therefore, there has been a problem that the ability of the zeolite to separate and adsorb CO ₂ is significantly reduced.

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 CO ₂ 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 CO ₂ absorption characteristic is lowered.

That is, if the aqueous amine solution is not treated so as to maintain a concentration above a certain level, the concentration of the aqueous amine solution decreases, and CO ₂ cannot be absorbed. For this reason, the technique of Patent Document 2 has a problem that a large-scale absorption / regeneration mechanism is required to adjust the concentration of the aqueous amine solution so that CO ₂ can be absorbed again.

The carbon dioxide absorbent disclosed in Patent Document 3 can absorb carbon dioxide (in other words, CO ₂ ) from a gas containing moisture and CO ₂ at room temperature. In Patent Document 3, for example, (i) absorption of carbon dioxide by a carbon dioxide absorbent is performed by adding moisture to the carbon dioxide absorbent or (ii) adding a particulate wetting agent to the carbon dioxide absorbent. Prior to the start, water is contained in the carbon dioxide absorbent.

However, in Patent Document 3, the CO ₂ absorption rate (CO ₂ absorption amount per unit time) by the carbon dioxide absorbent is determined by the amount of moisture given to the carbon dioxide absorbent prior to the start of CO ₂ absorption. . For this reason, there was a problem that the CO ₂ absorption rate could not be changed (controlled) when the carbon dioxide absorbing material was absorbing CO ₂ .

Further, in an arrangement disclosed in Patent Document 3, water is added to the treatment gas containing carbon dioxide (CO _2). In this case, absorption of CO ₂ by the carbon dioxide absorbent starts when the gas to be treated, to which moisture has been added, contacts the carbon dioxide absorbent. However, in such a case, there has been a problem that the CO ₂ absorption rate by the carbon dioxide absorbing material cannot be made slower than the absorption rate of the carbon dioxide to be treated by the carbon dioxide absorbing material.

As described above, the techniques of Patent Documents 1 to 3 have a problem that the absorption amount (absorption rate) of CO ₂ in the carbon dioxide absorbent cannot be appropriately controlled with a simple configuration.

One aspect of the present disclosure has been made in view of the above-described problems, and a purpose thereof is a carbon dioxide absorption device or the like that can control the amount of CO ₂ absorbed in the carbon dioxide absorbent by a simple configuration. Is to realize.

In order to solve the above problem, a carbon dioxide absorption device according to one embodiment of the present disclosure includes a carbon dioxide absorbent that absorbs carbon dioxide contained in the gas from a gas containing moisture and carbon dioxide. The carbon dioxide absorber comprises a tetravalent lithium silicate, retains the carbon dioxide absorber and moisture, and at least part of the retained moisture is the dioxide. The apparatus further includes a holding unit that supplies the carbon absorbent, a supply unit that supplies the moisture to the holding unit, and a supply control unit that controls the operation of the supply unit.

According to the carbon dioxide absorber according to one aspect of the present disclosure, by a simple configuration, an effect that it is possible to control the CO ₂ absorption amount of the carbon dioxide absorbent.

It is a functional block diagram which shows the structure of the principal part of the carbon dioxide absorber which concerns on Embodiment 1. FIG. It is a functional block diagram which shows the schematic structure of the water | moisture-content supply part in the carbon dioxide absorption / absorption apparatus of FIG. It is a graph which shows an example of the measurement result with respect to the powder X using XRD. It is a diagram illustrating an example of a measuring mechanism for measuring the CO ₂ absorption amount by the carbon dioxide absorber of Figure 1. It is a figure which shows an example of the measurement result in the measurement mechanism of FIG. It is a figure which shows another example of the measurement result in the measurement mechanism of FIG. It is a figure which shows an example of the moisture content of the carbon dioxide absorber of FIG. In the carbon dioxide absorption absorbing device of FIG. 1 is a diagram schematically showing the relationship between the amount of CO ₂ absorption and moisture per unit time of the carbon dioxide absorbent. It is a figure which shows an example of the 1st table in the carbon dioxide absorption / absorption apparatus of FIG. In the carbon dioxide absorber of FIG. 1 is a diagram illustrating the flow of processing for controlling the CO ₂ concentration. It is a functional block diagram which shows the structure of the principal part of the carbon dioxide absorber which concerns on Embodiment 2. It is a functional block diagram which shows the schematic structure of the water | moisture-content supply part in the carbon dioxide absorption / absorption apparatus of FIG. It is a figure which shows another example of the measurement result in the measurement mechanism of FIG. In the carbon dioxide absorption absorbing device of FIG. 11 is a diagram schematically showing the relationship between the pH of the CO ₂ absorption and moisture per unit time of the carbon dioxide absorbent. It is a figure which shows an example of the 2nd table in the carbon dioxide absorption / absorption apparatus of FIG. In the carbon dioxide absorber of FIG. 11 is a diagram illustrating the flow of processing for controlling the CO ₂ concentration. It is a functional block diagram which shows the structure of the principal part of the carbon dioxide absorber which concerns on Embodiment 3. In the carbon dioxide absorber of FIG. 17 is a diagram illustrating the flow of processing for controlling the CO ₂ concentration. It is a figure which shows schematic structure of the air cleaner which concerns on Embodiment 4. FIG.

Embodiment 1
Hereinafter, Embodiment 1 of the present disclosure will be described with reference to FIGS. First, the outline of the carbon dioxide absorber 1 of the present embodiment will be described with reference to FIG. FIG. 1 is a functional block diagram illustrating a configuration of a main part of the carbon dioxide absorber 1.

(Outline of carbon dioxide absorber 1)
The carbon dioxide absorption device 1 includes a carbon dioxide absorbent 10, a holding unit 11, a moisture supply unit 12 (supply unit), a control unit 13, a detection unit 14, and a storage unit 15. The control unit 13 includes a difference calculation unit 131 and an addition amount setting unit 132 (supply control unit). The carbon dioxide absorbent 10 is placed on the holding unit 11.

Note that the carbon dioxide absorber 1 may be provided with a member (for example, a pump or a fan) for sending air into the carbon dioxide absorbent 10 and the detector 14. However, these members are not shown in FIG.

The carbon dioxide absorbent 10 absorbs CO ₂ contained in the gas. Specifically, the carbon dioxide absorbent 10 separates at least a part of CO ₂ from a gas in a space containing moisture (ie, water vapor) and CO ₂ (ie, carbon dioxide gas), and absorbs the CO ₂ . To do.

In the present embodiment, a case where a low concentration of CO ₂ is absorbed by the carbon dioxide absorbent 10 will be described. Here, “low concentration” means, for example, a concentration of 5000 ppm or less, and particularly a concentration of 3000 ppm or less when the influence on the human body is taken into consideration. “Space” means an environment in which humans (or other living organisms) can survive. Therefore, the atmospheric pressure in the space of the present embodiment is near atmospheric pressure (1 atm).

Further, as will be described later, the carbon dioxide absorbent 10 contains tetravalent lithium silicate (Li ₄ SiO ₄ ). Here, “tetravalent lithium silicate” means “lithium silicate having four monovalent Li”. In this embodiment, if the ratio of the tetravalent lithium silicate to the total amount of substances contained in the carbon dioxide absorbent 10 is, for example, 50% or more, the lithium silicate is the main component of the carbon dioxide absorbent 10. And

As described below, the amount of CO ₂ absorbed per unit time in the carbon dioxide absorbent 10 (that is, the pH of water) by changing the amount of moisture contained in the carbon dioxide absorbent 10 or the nature of moisture (eg, pH of moisture) (that is, CO ₂ absorption rate) can be adjusted. That is, the CO ₂ absorption rate can be adjusted by changing the moisture content in the carbon dioxide absorbent 10.

The holding unit 11 is a member on which the carbon dioxide absorbent 10 is placed. That is, the holding unit 11 is a support member that supports (holds) the carbon dioxide absorbent 10. Further, as will be described below, moisture is supplied to the holding unit 11 from the water supply unit 12.

The holding unit 11 holds the moisture and supplies part of the held moisture to the carbon dioxide absorbent 10. For this reason, the moisture supply unit 12 can supply moisture to the carbon dioxide absorbent 10 via the holding unit 11. Therefore, according to the supply of moisture from the moisture supply unit 12 to the holding unit 11, the moisture content in the carbon dioxide absorbent 10 can be changed.

The holding unit 11 only needs to be able to hold the carbon dioxide absorbent 10 and moisture, and the material of the holding unit 11 is not particularly limited. As an example, as the material of the holding unit 11, cellulose, melamine resin, or the like can be used. In the present embodiment, the case where the holding unit 11 is a filter paper made of cellulose will be mainly described as an example.

The moisture supply unit 12 supplies moisture (water) to the holding unit 11. FIG. 2 is a functional block diagram showing a schematic configuration of the moisture supply unit 12. As shown in FIG. 2, the water supply unit 12 includes a water storage unit 121 that stores water to be supplied to the holding unit 11, and a water supply unit 122 that sends water from the water storage unit 121 to the holding unit 11. . The moisture supply unit 12 further includes a water channel 123 (eg, a tube or a pipe) that connects the water storage unit 121 and the water supply unit 122 to each other. The water supply unit 122 extracts a predetermined amount of water from the water storage unit 121 through the water channel 123 and supplies the extracted water to the holding unit 11.

As an example, the water storage unit 121 is a container that is made of a known material (eg, a plastic material or a glass material) and receives a predetermined amount of water. In the present embodiment, the water stored in the water storage unit 121 is ion exchange water having a pH of about 7.

Further, the water supply unit 122 includes a pump 124 (for example, a liquid supply pump or a syringe pump) for supplying (transporting) water to the holding unit 11. The amount of water supplied from the moisture supply unit 12 to the holding unit 11 can be set (changed) by the control unit 13 (more specifically, an addition amount setting unit 132 described later) controlling the operation of the pump 124. .

However, the operation of the pump 124 may be controlled by an external device different from the carbon dioxide absorber 1. In this case, the user can input the external device and set the amount of water supplied from the moisture supply unit 12 to the holding unit 11 based on the input.

The detection unit 14 detects (measures) the CO ₂ concentration in the gas in the space where the carbon dioxide absorption device 1 is provided. In addition, the detection unit 14 gives a detection value (detection result) of the CO ₂ concentration to the control unit 13 (more specifically, a difference calculation unit 131 described later).

Note that the detection method of the CO ₂ concentration in the detection unit 14 is not particularly limited. As the detection method, a method using a semiconductor sensor (semiconductor method), an electrochemical method, an infrared absorption method, or the like may be used.

When the semiconductor detection method is adopted, there are advantages such as (i) the cost of the detection unit 14 can be reduced, and (ii) the detection unit 14 can be given resistance to severe environmental conditions. . As a material for the semiconductor sensor, a semiconductor such as SnO ₂ or ZnO (eg, n-type semiconductor) is used. From the viewpoint of improving the selectivity of the detection target, SnO ₂ added with La is used. Is particularly preferred.

Further, when an infrared absorption detection method is employed, there are advantages such as (i) the sensitivity of the detection unit 14 can be increased, and (ii) the selectivity of the detection target can be improved. . When an electrochemical detection method is employed, for example, a sodium ion conductor is used as the conductive ion species of the solid electrolyte.

The control unit 13 comprehensively controls each unit (hardware element) of the carbon dioxide absorber 1. The function of the control unit 13 may be realized by executing a program stored in the storage unit 15 by a CPU (Central Processing Unit). The storage unit 15 stores various programs executed by the control unit 13 and data used by the programs. The storage unit 15 stores a first table 151 described later.

Note that specific operations of the difference calculation unit 131 and the addition amount setting unit 132 in the control unit 13 will be described later. In the present embodiment, for convenience of explanation, the difference calculation unit 131 and the addition amount setting unit 132 are illustrated as separate functional units. However, the addition amount setting unit 132 has the function of the difference calculation unit 131 in combination. May be. That is, the difference calculation unit 131 and the addition amount setting unit 132 may be realized as an integrated functional unit. The same applies to the pH setting unit 232 (supply control unit) described in the second embodiment described later.

As will be described in detail below, the control unit 13 (specifically, the addition amount setting unit 132) has a function as a supply control unit that controls the supply of moisture from the moisture supply unit 12 to the holding unit 11. More specifically, the addition amount setting unit 132 adjusts the amount of moisture supplied from the moisture supply unit 12 to the holding unit 11 based on the detected value of the CO ₂ concentration in the detection unit 14.

(Example of method for producing carbon dioxide absorbent 10)
Hereinafter, an example of a method for producing the carbon dioxide absorbent 10 will be described. First, the silicon dioxide (SiO ₂ ) and lithium nitrate (LiNO ₃ ) are weighed so that the molar ratio is 1: 4 (weighing step). Subsequently, the weighed silicon dioxide and lithium nitrate are placed in a container together with ethanol.

Then, silicon dioxide and lithium nitrate are mixed by a ball mill using Al ₂ O ₃ balls for about 24 hours (mixing step). Thereafter, ethanol is removed by an evaporator to obtain a mixed powder of silicon dioxide and lithium nitrate.

And the obtained mixed powder is grind | pulverized with a mortar, and the said mixed powder is heated for 10 hours at the temperature of about 900 degreeC in an electric furnace (heating process). Subsequently, the heated mixed powder is pulverized with a mortar. (Crushing process). As a result, a powdery (powdered) carbon dioxide absorbent 10 containing Li ₄ SiO ₄ is produced.

Hereinafter, the carbon dioxide absorbent 10 (powder) prepared by the above preparation method is referred to as powder X. From the observation result by SEM (Scanning Electron Microscope), it was confirmed that the particle size of the powder X was about 5 to 30 μm.

It should be noted that the mixing time in the mixing step is merely an example. The mixing time may be appropriately set according to the total weight of silicon dioxide and lithium nitrate weighed in the weighing step.

Also, the heating temperature and heating time in the heating step are merely examples. The heating temperature and the heating time may be appropriately set depending on the specifications of the electric furnace to be used. As an example, the heating temperature may be 600 ° C. or higher and 1000 ° C. or lower. The heating time may be 5 hours or more and 40 hours or less.

(Identification of powder X by XRD)
Subsequently, the inventors of the present application (hereinafter, the inventors) identify the powder X using XRD (X-Ray Diffraction, X-ray diffractometer), whereby the powder X becomes Li _4. It was confirmed that SiO ₄ was actually included.

FIG. 3 is a graph showing an example of measurement results for powder X using XRD. In FIG. 3, the horizontal axis represents the diffraction angle (°), and the vertical axis represents the X-ray intensity (arbitrary unit) after scattering in the measurement object.

Also, the legend “Li: Si = 4.0: 1” in FIG. 3 shows the measurement results when the measurement object is powder X. On the other hand, the legends “Li: Si = 4.2: 1”, “Li: Si = 4.1: 1”, “Li: Si = 3.9: 1”, and “Li: Si = 3. "8: 1" is the measurement result when the measurement object is other than the powder X (powder obtained with the molar ratio of lithium nitrate and silicon dioxide other than 1: 4 in the weighing step in the above production method). Indicates.

In addition, the legends “Li ₄ SiO ₄ ” (circle mark), “Li ₂ SiO ₃ ” (triangle mark), and “Li ₂ CO ₃ ” (square mark) in FIG. 3 are respectively Li ₄ SiO ₄ as a reference. , Li ₂ SiO ₃ , and Li ₂ CO ₃ measurement results are shown.

As shown in FIG. 3, the graph of the measurement results shown in the legend “Li: Si = 4.0: 1” has a peak at substantially the same diffraction angle as that of Li ₄ SiO ₄ as a reference. Therefore, from the measurement result, it was confirmed that the powder X contains Li ₄ SiO ₄ .

(Relationship between added amount of water and CO ₂ absorption capacity)
Next, referring to FIG. 4 to FIG. 6, the amount of water added to the holding unit 11 (the amount of water supplied from the water supply unit 12 to the holding unit 11) and the CO ₂ absorption capacity (CO ₂ ) of the carbon dioxide absorbent 10. ₂ ) (also referred to as “ ₂ absorption characteristics”).

FIG. 4 is a diagram illustrating an example of a measurement mechanism for measuring the CO ₂ absorption amount (that is, the CO ₂ absorption characteristic of the carbon dioxide absorbent 10) by the carbon dioxide absorbent 10 (eg, powder X). 5 and 6 are graphs showing examples of measurement results obtained by the measurement mechanism of FIG.

As shown in FIG. 4, in the measurement mechanism, the carbon dioxide absorbent 10, the holding unit 11, and the detection unit 14 are arranged in the container 150. According to the measurement mechanism, the CO ₂ absorption amount of the carbon dioxide absorbent 10 can be measured by measuring the CO ₂ concentration in the gas contained in the container 150.

The container 150 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 150. In addition, the material of the container 150 will not be specifically limited if the above-mentioned measurement environment can be provided. In the embodiment, the material of the container 150 is, for example, acrylic. In the measurement mechanism of FIG. 4, the detection unit 14 measures the concentration of CO _{2 in} the gas contained in the container 150 in a sealed state with the door closed.

The measurement method of the CO ₂ absorption characteristics of the carbon dioxide absorbent 10 in the measurement mechanism of FIG. 4 is as follows. First, a container 150 (made of acrylic) having an internal volume of 12 liters is placed in an atmosphere having a CO ₂ concentration of about 450 ppm, room temperature, and humidity of 45-50% RH (Relative Humidity), and the inside of the container 150 is the same as the atmosphere. And the atmosphere.

Next, a predetermined amount (0 to 500 μL) of water (ion-exchanged water having a pH of about 7) is added to the holding unit 11, and the carbon dioxide absorbent 10 (powder X) is added to the holding unit 11 by 0.0. 15 g was placed. Thereafter, only 0.05 g of the carbon dioxide absorbent 10 was removed from the holding unit 11, and the remaining 0.1 g of the carbon dioxide absorbent 10 was placed on the holding unit 11. Subsequently, the door of the container 150 was closed, and the inside of the container 150 was sealed. In the sealed state, the CO ₂ concentration contained in the container 150 was measured over time by the detection unit 14. An example of the measurement result is shown in FIGS. 5 and 6 described below.

FIG. 5 is a graph showing an example of measurement results when a filter paper made of cellulose is used as the holding unit 11. FIG. 5 shows the amount of CO ₂ absorbed by the carbon dioxide absorbent 10 (more specifically, detected by the detection unit 14 when the amount of water added to the holding unit 11 (filter paper) is changed variously. The measurement result about the time transition of the amount of reduction of CO ₂ in the container 150 is shown.

In the graph of FIG. 5, the horizontal axis indicates time (elapsed time from the measurement start time) (minutes), and the vertical axis indicates the CO ₂ absorption amount (mg) by the carbon dioxide absorbent 10. FIG. 5 shows the measurement results for five types of water addition amounts of “0 μL” (no addition), “100 μL”, “200 μL”, “300 μL”, “400 μL”, and “500 μL”. Yes.

As shown in FIG. 5, the amount of CO ₂ absorbed by the carbon dioxide absorbent 10 within a predetermined time (that is, the CO ₂ absorption rate of the carbon dioxide absorbent 10) increases as the amount of water added increases. Was confirmed. Moreover, when the addition amount of water was 0 μL (no addition), it was confirmed that the CO ₂ absorption amount by the carbon dioxide absorbent 10 was 0 mg at all times.

FIG. 6 is a graph showing an example of a measurement result when a melamine resin container is used as the holding unit 11. FIG. 6 shows a measurement result of the temporal transition of the CO ₂ absorption amount by the carbon dioxide absorbent 10 when the amount of water added to the holding unit 11 (container) is 500 μL.

As shown in FIG. 6, even when a melamine resin container is used as the holding unit 11, the holding unit 11 can sufficiently hold moisture, and the carbon dioxide absorbent 10 suitably absorbs CO _2. It was confirmed that it was possible to

(A study on the mechanism of increase of CO ₂ absorption rate)
As described above, the inventors have newly found that the CO ₂ absorption rate of the carbon dioxide absorbent 10 can be increased by increasing the amount of water added to the holding unit 11. However, the mechanism (principle) of increasing the CO ₂ absorption rate of the carbon dioxide absorbent 10 by increasing the amount of moisture added has not been elucidated at the present time. However, the inventors speculate an example of the mechanism as follows.

(Inference): Li ₄ SiO ₄ contained in the carbon dioxide absorbent 10 contains water to partially dissolve the surface of Li ₄ SiO ₄ . _Then, by increasing the amount of water to be contained in the Li 4 SiO _{_4,} dissolution of the surface of the Li 4 SiO ₄ is promoted. As a result, the CO ₂ absorption reaction in the carbon dioxide absorbent 10 is promoted.

Further, the inventors of the measurement mechanism shown in FIG. 4 have said dioxide dioxide at each time point before and after the measurement of the CO ₂ absorption characteristics of the carbon dioxide absorbent 10 for each of the five types of water addition described above. The ratio of moisture contained in the carbon absorbent 10 (that is, the moisture content of the carbon dioxide absorbent 10) was further measured. FIG. 7 is a table showing an example of the measurement result of the moisture content.

The moisture content of the carbon dioxide absorbent 10 is measured by measuring the weight of the carbon dioxide absorbent 10 before and after the process of dehydrating water from the carbon dioxide absorbent 10 (dehydration process) using a moisture meter. It was done by doing. In addition, the dehydration process was performed by heating the carbon dioxide absorbent 10 at 120 ° C. for about 1 minute.

First, prior to the start of measurement of the CO ₂ absorption characteristics, the moisture content of 0.05 g of the carbon dioxide absorbent 10 removed from the holding unit 11 was measured. Hereinafter, the moisture content is referred to as “a moisture content before measurement”.

Further, 120 minutes after the start of measurement of the CO ₂ absorption characteristics, the carbon dioxide absorbent 10 was quickly taken out from the container 150, and the moisture content of the taken carbon dioxide absorbent 10 was measured. Hereinafter, the moisture content is referred to as “moisture content after measurement”.

As shown in FIG. 7, the moisture content after measurement is lower than the moisture content before measurement except when the amount of moisture added is 0 μL (when moisture is not added to the holding unit 11). It was confirmed. This is presumed to be due to a decrease in the moisture content of the carbon dioxide absorbent 10 because a part of the water contained in the carbon dioxide absorbent 10 has evaporated inside the container 150.

In FIG. 5 described above, when the amount of water added is 100 μL or 200 μL, the CO ₂ absorption rate of the carbon dioxide absorbent 10 decreases to almost 0 in the time zone near 120 minutes from the start of measurement. It is shown. The decrease in the absorption rate is assumed to be due to the decrease in the moisture content of the carbon dioxide absorbent 10 described above.

On the other hand, as shown in FIG. 7, when the amount of water added was 0 μL, the moisture content after the measurement increased with respect to the moisture content before the measurement (0%). However, as shown in FIG. 5 described above, absorption of CO ₂ by the carbon dioxide absorbent 10 was not confirmed when the amount of water added was 0 μL.

Therefore, when the amount of water added is 0 μL, it is estimated that the water content after measurement (15.12%) is insufficient to promote the CO ₂ absorption reaction in the carbon dioxide absorbent 10. . The same can be assumed for the case where the water content is 100 μL or 200 μL.

As described above, the measurement results of FIGS. 5-7 described above, when the CO ₂ absorption capacity of the carbon dioxide absorbent 10 has fallen, by further adding water to the holding portion 11, the CO ₂ It is understood that it is possible to maintain or improve the absorption capacity.

(Control method of CO ₂ absorption amount in carbon dioxide absorber 1)
The inventors have conceived a new method for controlling the CO ₂ absorption amount (CO ₂ absorption rate) in the carbon dioxide absorption device 1 based on the measurement results. Subsequently, an example of the control method will be described.

FIG. 8 shows the amount of CO ₂ absorbed per unit time of the carbon dioxide absorbent 10 (vertical axis, unit: g) (that is, CO ₂ absorption rate) and the amount of moisture W added to the holding unit 11 (horizontal axis, unit). : L) (hereinafter simply referred to as “addition amount W”).

As described above, the graph of FIG. 8 also shows that the CO ₂ absorption rate depends on the addition amount W. Here, in the graph of FIG. 8, the addition amount W at which the maximum value of the CO ₂ absorption rate is obtained is expressed as W _m in particular. W ₁ to W _m shown in FIG. 8 are set values of the addition amount W. As will be described later, all of W ₁ to W _X are smaller than W _m .

As described above, when 0 <W ≦ W _m , the CO ₂ absorption rate increases as W increases. On the other hand, when W> W _m , the CO ₂ absorption rate decreases even when W is increased. In addition, when W = 0, the CO ₂ absorption rate is zero. From these facts, it is understood that the CO ₂ absorption rate can be controlled in the numerical range from 0 to the maximum value by adjusting the addition amount W in the numerical range of 0 ≦ W ≦ W _m .

Here, the operations of the difference calculation unit 131 and the addition amount setting unit 132 will be described with reference to FIG. 1 again. The difference calculation unit 131 acquires the detection result (the detected value of the CO ₂ concentration) from the detection unit 14 from the detection unit 14. Then, the difference calculation unit 131, based on the detection result, calculates the CO ₂ absorption rate of the above (hereinafter, referred to as the detection value P1).

Subsequently, the difference calculation unit 131 calculates the difference between the detected value P1 (that is, the CO ₂ absorption amount per unit time) and the reference value of the predetermined CO ₂ absorption amount (hereinafter referred to as the reference value DT) as a difference. Calculated as value D. That is, the difference calculation unit 131 calculates D = P1−DT. Then, the difference calculation unit 131 supplies the difference value D to the addition amount setting unit 132.

The reference value DT may be set in advance at the time of product shipment of the carbon dioxide absorber 1, or may be set by the user. As an example, the reference value DT may be set to 1000 ppm which is a reference value such as the Building Sanitation Law. This numerical value (concentration) of 1000 ppm is an example of a CO ₂ concentration that is considered to possibly have an adverse effect on the human body (eg, there is a possibility that humans may be invited to sleepiness and concentration may be reduced).

The addition amount setting unit 132 acquires the difference value D from the difference calculation unit 131 and sets the addition amount W based on the difference value D. That is, the addition amount setting unit 132 controls the operation of the pump 124 of the moisture supply unit 12 based on the difference value D.

More specifically, the addition amount setting unit 132 refers to the first table 151 and sets (selects) the addition amount W according to the numerical range of the difference value D. In other words, the addition amount setting unit 132 can set the addition amount W according to the detection value P1 with reference to the first table 151. Here, the first table 151 is a predetermined table showing a correspondence relationship between the numerical range of the difference value D and the addition amount W (more specifically, the set value of the addition amount W). It should be noted that the first table 151 may be understood as a table showing the correspondence between the detection value P1 and the addition amount W.

FIG. 9 is a table showing an example of the first table 151. In the present embodiment, the case where the first table 151 is stored in the storage unit 15 is illustrated, but the first table 151 may be set inside the addition amount setting unit 132.

In the first table 151, X is an arbitrary integer. Also, 0 <S ₁ <S ₂ <... <S _X-1 <S _X , and 0 <W ₁ <W ₂ <... <W _X <W _m . That is, in the first table 151, S ₁ to S _X (threshold value of the difference value D) and W are set so that the addition amount W increases (so that the CO ₂ absorption rate can be increased) as the difference value D increases. the value of ₁ ~ _{W m} has been set. The values of X, S ₁ to S _X , and W ₁ to W _m may be set in advance when the carbon dioxide absorber 1 is shipped, or may be set by the user.

By providing the first table 151, in the addition amount setting unit 132, an appropriate addition amount is determined according to the degree of the difference value D (that is, how large the detected value P1 is relative to the reference value DT). W can be set stepwise (discrete). Therefore, the addition amount setting unit 132 can set the addition amount W by a simple process (calculation).

(Processing flow of CO ₂ concentration control in the carbon dioxide absorber 1)
Next, the flow of the CO ₂ concentration control processes S1 to S14 in the carbon dioxide absorber 1 will be described with reference to FIG. FIG. 10 is a flowchart illustrating the flow of the processing.

First, when the power of the carbon dioxide absorber 1 is turned on (ON), the detection unit 14 operates to detect the CO ₂ concentration in the gas in the space (S1). Subsequently, as described above, the difference calculation unit 131 acquires the detection result of the detection unit 14 and calculates the difference value D (S2). Then, the addition amount setting unit 132 sets the addition amount W according to the numerical range of the difference value D based on the first table 151.

First, the addition amount setting unit 132 determines whether D ≦ 0 (S3). When D ≦ 0 (YES in S3), the addition amount setting unit 132 sets the addition amount to W = 0 (addition amount corresponding to D ≦ 0, minimum value of W) (S4), S13 Proceed to (described later). On the other hand, if D ≦ 0 is not satisfied (NO in S3), the process proceeds to S5.

Subsequently, the addition amount setting unit 132 determines whether 0 <D <S ₁ (S5). When 0 <D <S ₁ (YES in S5), the addition amount setting unit 132 sets the addition amount to W = W ₁ (addition amount corresponding to 0 <D <S ₁ ) (S6). , Go to S13. On the other hand, 0 <D <if not _{S 1} (NO at S5), the process proceeds to S7.

Subsequently, the addition amount setting unit 132 determines whether or not S ₁ ≦ D <S ₂ (S7). When S ₁ ≦ D <S ₂ (YES in S 7), the addition amount setting unit 132 sets the addition amount to W = W ₂ (addition amount corresponding to S ₁ ≦ D <S ₂ ) ( The process proceeds to S8) and S13.

On the other hand, when S ₁ ≦ D <S ₂ is not satisfied (NO in S7), the addition amount setting unit 132 determines which numerical range in the first table 151 the value of D belongs to, and the same as described above. Then, the process of setting the addition amount W corresponding to the numerical range of D is performed. In FIG. 10, the processes from “NO at S7” to S9 are not shown.

Hereinafter, the processing after S9 will be described. The addition amount setting unit 132 determines whether S _X-1 ≦ D <S _X (S9). When S _X-1 ≦ D <S _X (YES in S9), the addition amount setting unit 132 sets the addition amount to W = W _X (addition amount corresponding to S _X-1 ≦ D <S _X ) (S10), and proceed to S13. On the other hand, if S _X-1 ≦ D <S _X is not satisfied (NO in S9), the process proceeds to S11.

Subsequently, the addition amount setting unit 132 determines whether D ≧ S _X (S11). If D ≧ S _X (YES in S11), the addition amount setting unit 132 sets the addition amount to W = W _m (addition amount corresponding to D ≧ S, maximum value of W) (S2). , Go to S13. On the other hand, if D ≧ S _X is not satisfied (NO in S11), the process returns to S1.

When the setting of the addition amount W in the addition amount setting unit 132 is completed, the detection unit 14 detects the CO ₂ concentration in the gas in the space at any two different times t1 and t2 (t2> t1). (S13). Note that the times t1 and t2 may be set in advance when the carbon dioxide absorption device 1 is shipped, or may be set by the user.

Then, the difference calculation unit 131, the detection result to get the difference and the variation of CO ₂ concentration between time t1 · t2 of the CO ₂ concentration in the CO ₂ concentration and time t1 at time t2 of the detector 14 (the difference Value). Subsequently, the difference calculation unit 131 determines whether the change amount is 0 or positive (S14).

If the amount of change in the CO ₂ concentration between times t1 and t2 is 0 or positive (YES in S14), the process returns to the above-described process S1 and the same process is repeated. This is because when the amount of change is 0 or positive, the CO ₂ concentration does not decrease with the passage of time, so it is considered preferable to continue the absorption of CO ₂ by the carbon dioxide absorbent 10. On the other hand, if the amount of change is negative (NO in S14), the process returns to S13 described above.

10 are repeated until the power source of the carbon dioxide absorber 1 is stopped (OFF). By repeating the process S1 ~ S14, when the power is turned ON carbon dioxide absorber 1, even if the CO ₂ concentration in the gas (the detected value P1) is high, the CO ₂ concentration below the reference value DT above Until finally can be lowered.

(Effect of the carbon dioxide absorber 1)
As described above, according to the carbon dioxide absorption device 1, the addition amount W is set by setting the addition amount W (the amount of moisture supplied from the moisture supply unit 12 to the holding unit 11) in the addition amount setting unit 132. Accordingly, the CO ₂ absorption amount (CO ₂ absorption rate) of the carbon dioxide absorbent 10 can be changed. That is, with a simple configuration, the moisture content in the carbon dioxide absorbent 10 (in this embodiment, the moisture content) can be changed arbitrarily, so that the CO ₂ absorption can be appropriately controlled. It becomes.

Furthermore, in the addition amount setting unit 132, the CO ₂ absorption amount can be controlled in a plurality of stages by adjusting the addition amount W within a numerical range of 0 ≦ W ≦ W _{m that} is greater than or equal to zero. For this reason, the CO ₂ absorption amount can also be set so that the carbon dioxide absorbent 10 does not absorb an excessive amount of CO ₂ . Therefore, useless consumption (deterioration) of the carbon dioxide absorbent 10 can be prevented.

In particular, when the above-described difference value D satisfies D ≦ 0 (that is, when the detection value P1 is equal to or less than the reference value DT), the addition amount is set to W = 0 (addition of moisture to the holding unit 11) Is stopped), the CO ₂ absorption capacity of the carbon dioxide absorbent 10 can be quickly reduced. For this reason, useless consumption of the carbon dioxide absorbent 10 can be particularly effectively prevented.

As described above, according to the carbon dioxide absorption device 1, it is possible to control the CO ₂ concentration in the gas within an appropriate range over a long period of time. Therefore, the carbon dioxide absorption device 1 is particularly suitable in a space where the CO ₂ concentration to be removed changes with time (eg, a space where ventilation can be restricted, which will be described later).

[Embodiment 2]
The second embodiment of the present disclosure will be described below with reference to FIGS. 11 to 16. 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.

(Configuration of carbon dioxide absorber 2)
FIG. 11 is a functional block diagram illustrating a configuration of a main part of the carbon dioxide absorption device 2 of the present embodiment. The carbon dioxide absorption device 2 is the same as the carbon dioxide absorption device 1 of the first embodiment described above, in which (i) the moisture supply unit 12 is replaced with the moisture supply unit 22 (supply unit), and (ii) the addition amount setting unit 132 of the control unit 13. Is replaced with a pH setting unit 232, respectively.

In addition, the control part of the carbon dioxide absorption apparatus 2 is called the control part 23 for the distinction with the control part 13. The storage unit 15 stores a second table 251 (described later) instead of the first table 151 described above.

FIG. 12 is a functional block diagram showing a schematic configuration of the moisture supply unit 22. As shown in FIG. 12, the water supply unit 22 is different from the water supply unit 12 described above in that it includes a plurality of water storage units that store water supplied to the holding unit 11. As an example, the water supply unit 22 includes five water storage units 221a to 221e. The water storage units 221a to 221e may be collectively referred to as the water storage unit 221.

In FIG. 12, for simplicity, only three

water storage units

221a, 221b, and 221e out of the five water storage units 221a to 221e are illustrated. The same applies to water channels 223a to 223e described below.

And as FIG. 12 shows, in the water | moisture-content supply part 22, the aqueous solution which has different pH in each of the some water storage part 221 is stored. As an example, each of the five water storage units 221 stores aqueous solutions having five different pH values of “pH 0”, “pH 2”, “pH 7”, “pH 12”, and “pH 14”.

The water supply unit 22 further includes water channels 223a to 223e that connect the water storage units 221a to 221e and the water supply unit 122 to each other. As an example, consider a case where an aqueous solution of pH 0 is stored in the water storage unit 221a. In this case, the water supply unit 122 (more specifically, the pump 124) takes out the aqueous solution of pH 0 from the water storage unit 221a through the water channel 223a.

As described above, according to the configuration of the water supply unit 22, the water supply unit 122 selects a specific water storage unit (for example, the water storage unit 221a) from the plurality of water storage units 221 (water storage units 221a to 221e). A predetermined amount of water can be taken out from the water reservoir.

The pH setting unit 232 in FIG. 11 described above adds to the above-described addition amount setting unit 132 a water storage unit (eg, water storage unit 221a) that is a target for extracting water from the plurality of water storage units 221 in the water supply unit 22. A function for selecting is added. That is, the pH setting unit 232 can set the pH of the moisture in addition to the added amount W of the moisture. A specific example of the operation of the pH setting unit 232 will be described in detail below.

(Relationship between water pH and CO ₂ absorption capacity)
Next, the relationship between the pH of moisture added to the holding unit 11 and the CO ₂ absorption capacity of the carbon dioxide absorbent 10 will be described with reference to FIG.

FIG. 13 is a graph (a graph paired with FIG. 5 described above) showing an example of measurement results when cellulose filter paper is used as the holding unit 11 in the measurement mechanism of FIG. 4 described above. Specifically, FIG. 13 shows the measurement result of the temporal transition of the amount of CO ₂ absorbed by the carbon dioxide absorbent 10 when water having a predetermined pH is added to the holding unit 11 (filter paper). ing.

FIG. 13 shows measurement results for six cases of “pH 0”, “pH 2.4”, “pH 7”, “pH 12”, “pH 13”, and “pH 14”. Further, the amount of water added to the holding unit 11 is 300 μL at any pH. Other conditions are the same as those in the case of FIG.

As shown in FIG. 13, the amount of CO ₂ absorbed by the carbon dioxide absorbent 10 within a predetermined time (that is, the CO ₂ absorption rate of the carbon dioxide absorbent 10) may increase as the pH of water increases. confirmed.

(Consideration of mechanism of increase of CO ₂ absorption rate in this embodiment)
As described above, the inventors have confirmed that the CO ₂ absorption rate of the carbon dioxide absorbent 10 can be increased by increasing the pH of the water added to the holding unit 11. However, the mechanism (principle) of increasing the CO ₂ absorption rate of the carbon dioxide absorbent 10 by increasing the pH of the moisture has not been elucidated at the present time. However, the inventors speculate an example of the mechanism as follows.

(Inference): Since the pH of carbon dioxide gas is relatively low (weakly acidic), the carbon dioxide absorbent 10 increases as the pH of water added to the holding unit 11 increases (eg, as the alkalinity of water increases). The CO ₂ absorption reaction in is promoted.

(Control method of CO ₂ absorption amount in carbon dioxide absorber 2)
The inventors have conceived a new method for controlling the CO ₂ absorption amount (CO ₂ absorption rate) different from that of the first embodiment based on the measurement result. Subsequently, an example of the control method will be described.

FIG. 14 shows the amount of CO ₂ absorbed per unit time of the carbon dioxide absorbent 10 (vertical axis, unit: g) (that is, CO ₂ absorption rate) and the pH of water relative to the holding unit 11 (horizontal axis, unit: L). It is a graph which shows the relationship with) schematically. Hereinafter, a letter (symbol) representing the pH of moisture is assumed to be A. As described above, the graph of FIG. 14 also shows that the CO ₂ absorption rate depends on the pH of water (the value of A).

Here, in the graph of FIG. 14, the value of A from which the minimum value of the CO ₂ absorption rate is obtained is expressed as A ₁ in particular. As an example, A ₁ = 0. Further, the value of A the maximum value of the CO ₂ absorption rate is obtained, expressed as a particular _{A m.} As an example, A _m = 14. A ₁ to A _m shown in FIG.

As shown in FIG. 14, the CO ₂ absorption rate monotonously increases with respect to A in the numerical range of A ₁ (= 0) ≦ A ≦ A _m (= 14). From this, it is understood that the CO ₂ absorption rate can be controlled in the numerical range from the minimum value to the maximum value by adjusting the value of A (water pH) in the above numerical range.

In the present embodiment, the pH setting unit 232 sets the value of A based on the difference value D acquired from the difference calculation unit 131. More specifically, the pH setting unit 232 refers to the second table 251 and sets the value A according to the numerical range of the difference value D. In other words, the pH setting unit 232 can set the value of A according to the detection value P1 with reference to the second table 251. Here, the second table 251 is a predetermined table indicating the correspondence between the numerical range of the difference value D and the value of A (more specifically, the set value of A). It should be noted that the second table 251 may be understood as a table indicating the correspondence between the detection value P1 and the value A.

FIG. 15 is a table showing an example of the second table 251. In the present embodiment, the case where the second table 251 is stored in the storage unit 15 is illustrated, but the second table 251 may be set inside the pH setting unit 232.

In the second table 251, X and S ₁ to S _X are the same as those in the case of the first table 151 (FIG. 9) described above, and a description thereof will be omitted. In the second table 251, the values of X and S ₁ to S _X may be the same as or different from those of the first table 151 described above.

In the second table 251, A ₁ (= 0) <A ₂ <... <A _X <A _m (= 14). That is, in the second table 251, the values of S ₁ to S _X and A ₁ to A _m are set so that the value of A increases as the difference value D increases (so that the CO ₂ absorption rate can be increased). Is set. As in the first embodiment, the values of A ₁ to A _m may be set in advance when the carbon dioxide absorber 1 is shipped, or may be set by the user.

By providing the second table 251, the pH setting unit 232 can set an appropriate value of A stepwise in accordance with the degree of the difference value D. For this reason, the pH setting unit 232 can also set the value of A by a simple process.

(Processing flow of CO ₂ concentration control in the carbon dioxide absorber 2)
Subsequently, the flow of the CO ₂ concentration control processes S21 to S34 in the carbon dioxide absorber 2 will be described with reference to FIG. FIG. 16 is a flowchart illustrating the flow of the processing.

Note that S21 to S22, S23, S25, S27, S29, and S31, and S33 to S34 in FIG. Since it is the same process, description is abbreviate | omitted. Hereinafter, S24, S26, S28, S30, and S32 and their peripheral processing will be described.

First, when D ≦ 0 (NO in S23), the pH setting unit 232 stops adding moisture to the holding unit 11 (S24). That is, the pH setting unit 232 sets the above-described addition amount W to W = 0, and does not cause the moisture supply unit 22 to supply moisture to the holding unit 11. Then, the process proceeds to S33.

If 0 <D <S ₁ (YES in S25), the pH setting unit 232 sets the value of A to A = A ₁ (= 0) (the value of A corresponding to 0 <D <S ₁ , A) (S26), and the process proceeds to S33.

When S ₁ ≦ D <S ₂ (YES in S 27), the pH setting unit 232 sets the value of A to A = A ₂ (the value of A corresponding to S ₁ ≦ D <S ₂ ). Set (S28) and proceed to S33.

If S ₁ ≦ D <S ₂ is not satisfied (NO in S27), the pH setting unit 232 determines which numerical range in the second table 251 the value of D belongs to, A process of setting a value of A corresponding to the numerical value range of D is performed. Also in FIG. 16, as in FIG. 10 described above, the processes from “NO at S27” to S29 are not shown.

If S _X-1 ≦ D <S _X (YES in S29), the pH setting unit 232 sets the value of A to A = A _X (S _X-1 ≦ D <S _X corresponding to A (S30), and the process proceeds to S33.

If D ≧ S _X (YES in S31), the pH setting unit 232 sets the value of A to A = A _m (the value of A corresponding to D ≧ S, the maximum value of A). (S32), the process proceeds to S33.

Note that S21 to S34 of this embodiment are also repeated until the power of the carbon dioxide absorber 1 is turned off, as in S1 to S14 of FIG. For this reason, as in the first embodiment, even when the CO ₂ concentration (detection value P1) in the gas is high when the carbon dioxide absorber 2 is turned on, the CO ₂ concentration is set to the above-described reference. It can be finally reduced to a value DT or less.

(Effect of the carbon dioxide absorber 2)
As described above, the carbon dioxide absorbent 10 can also be obtained by changing the pH (value of A) of the water instead of the amount of water (addition amount W) supplied from the water supply unit 22 to the holding unit 11. The amount of CO ₂ absorbed (and CO ₂ absorption rate) can be adjusted.

In consideration of this point, the carbon dioxide absorption device 2 of the present embodiment sets the value of A in the pH setting unit 232, so that the CO ₂ absorption amount (CO _{2) of the} carbon dioxide absorbent 10 according to the value of A. (Absorption rate) is changed.

That is, the carbon oxide absorption device 2 can also arbitrarily change the moisture content in the carbon dioxide absorbent 10 (in this embodiment, the pH of the moisture), so that the amount of CO ₂ absorption can be controlled appropriately. Is possible. Therefore, the carbon dioxide absorption device 2 can provide the same effect as that of the first embodiment.

In addition, in the pH setting part 232, you may further perform the process similar to the addition amount setting part 132 of Embodiment 1. FIG. That is, the pH setting unit 232 may further set not only the value A but also the addition amount W according to the numerical range of the difference value D described above.

For example, the pH setting unit 232 can further set the addition amount W by referring to the first table 151 described above. According to this configuration, since both the pH and amount of water added to the holding unit 11 can be set, the CO ₂ absorption amount (or CO ₂ absorption rate) can be controlled with higher accuracy.

[Embodiment 3]
The third embodiment of the present disclosure will be described below with reference to FIGS. 17 and 18.

(Configuration of carbon dioxide absorber 3)
FIG. 17 is a functional block diagram illustrating a configuration of a main part of the carbon dioxide absorption device 3 of the present embodiment. The carbon dioxide absorption device 3 has a configuration in which a heating unit 35 and a heating control unit 333 are added to the carbon dioxide absorption device 1 of the first embodiment. In order to distinguish from the control unit 13, the control unit of the carbon dioxide absorber 3 is referred to as a control unit 33. As shown in FIG. 17, the heating control unit 333 is provided in the control unit 33.

The heating unit 35 heats the holding unit 11 and removes at least a part of the moisture added to the holding unit 11. The heating unit 35 may be, for example, a heater or a microwave irradiator, but is not limited thereto.

The heating temperature in the heating unit 35 (the temperature at which the holding unit 11 is heated) is preferably set within a temperature range where the holding unit 11 does not burn (eg, 60 ° C. to 200 ° C.). In particular, when the material of the holding unit 11 is an organic substance (eg, cellulose), it is preferable to set the heating temperature to about 60 to 100 ° C. in order to avoid burning the organic substance.

The heating control unit 333 controls the operation of the heating unit 35. In the present embodiment, a case where the operation of the heating unit 35 is controlled by the heating control unit 333 will be described as an example. As will be described below, the heating control unit 333 is based on the moisture addition history (may be referred to as supply history) to the holding unit 11 of the moisture supply unit 12 (hereinafter, also simply referred to as “addition history”). The operation of the heating unit 35 may be controlled. Here, the addition history is a history in which the moisture supply unit 12 supplies (transports) moisture to the holding unit 11.

However, the operation of the heating unit 35 may be controlled by an external device different from the carbon dioxide absorber 3. In this case, the user can give an input to the external device and operate the heating unit 35 based on the input.

(Flow of CO ₂ concentration control process in the carbon dioxide absorber 3)
Next, the flow of CO ₂ concentration control processes S41 to S56 in the carbon dioxide absorber 3 will be described with reference to FIG. FIG. 18 is a flowchart illustrating the flow of the processing.

It should be noted that S41 to S43, S45, and S47 to 56 in FIG. 18 are the same processes as S1 to S3, S4, and S5 to S14 in FIG. That is, FIG. 18 may be understood as a flowchart in which S44 and S46 are added to FIG. Hereinafter, S44 and S46 and their peripheral processing will be described.

In this embodiment, when the addition amount setting unit 132 gives an instruction to the moisture supply unit 12 to add moisture to the holding unit 11, the addition time setting unit 132 sets the operation time of the moisture supply unit 12 based on the instruction. Check. The addition amount setting unit 132 stores a log (record) indicating the operation time in the storage unit 15 as “addition history”.

First, when D ≦ 0 (YES in S43), the heating control unit 333 confirms whether the above-described addition history is present (stored) in the storage unit 15 (S44). If the addition history does not exist (NO in S44), the process proceeds to S45. That is, in this case, the heating control unit 333 does not operate the heating unit 35 and the state where moisture has not been added to the holding unit 11 is maintained as it is.

On the other hand, when the addition history exists (YES in S44), the heating control unit 333 operates the heating unit 35 in order to remove at least part of the moisture already added to the holding unit 11 ( S46). For example, when removing all of the moisture from the holding unit 11, the heating control unit 333 operates the heating unit 35 at a predetermined heating temperature (eg, 100 ° C.) over a predetermined heating time. Good.

As an example, the predetermined heating time is a time during which the maximum amount of moisture that can be held by the holding unit 11 can be removed when the holding unit 11 is heated at the predetermined heating temperature (100 ° C.). The predetermined heating time may be set in advance when the carbon dioxide absorption device 1 is shipped, or may be set by the user.

(Effect of the carbon dioxide absorber 3)
As an example, the above-described difference value D is D ≦ 0 (that is, the detected value P1 is equal to or less than the reference value DT), and the above-described addition history exists (that is, dioxide dioxide). In the case where the carbon absorption device 3 causes the carbon dioxide absorbent 10 to absorb CO ₂ at least once), it can be said that the necessity of maintaining the CO ₂ absorption capacity in the carbon dioxide absorbent 10 is low. This is because it is considered that the CO ₂ concentration in the gas has already been sufficiently reduced by the absorption of CO ₂ by the carbon dioxide absorbent 10 so far.

Nevertheless, even in such a case (hereinafter, unnecessary case), if the CO ₂ absorption capacity is still maintained, there is a possibility that wasteful consumption (deterioration) of the carbon dioxide absorbent 10 may occur. . Based on this point, the carbon dioxide absorption device 3 of the present embodiment is configured to control the operation of the heating unit 35 by the heating control unit 333 and remove at least a part of the moisture added to the holding unit 11. ing.

According to this configuration, in an unnecessary case, the heating unit 35 is operated in accordance with an instruction from the heating control unit 333 to quickly reduce the CO ₂ absorption amount (CO ₂ absorption rate) of the carbon dioxide absorbent 10. it can. For this reason, useless consumption of the carbon dioxide absorbent 10 in an unnecessary case can be effectively prevented.

As described above, according to the carbon dioxide absorption device 3 of the present embodiment, by providing the heating control unit 333 and the heating unit 35, compared to the carbon dioxide absorption device 1 of the above-described first embodiment, CO ₂ absorption. The amount can be controlled with higher accuracy. In addition, you may further provide the heating control part 333 and the heating part 35 in the carbon dioxide absorption apparatus 2 of above-mentioned Embodiment 2. FIG.

In the present embodiment, the case where the operation of the heating unit 35 is controlled in consideration of both the difference value D and the addition history is illustrated. However, the operation of the heating unit 35 may be controlled considering only the difference value D. As an example, the heating control unit 333 may operate the heating unit 35 regardless of the presence or absence of the addition history when D ≦ 0. Also with this configuration, wasteful consumption of the carbon dioxide absorbent 10 can be prevented.

[Embodiment 4]
The following describes Embodiment 4 of the present disclosure with reference to FIG. In this embodiment, an example of an electronic device including the carbon dioxide absorption device according to one aspect of the present disclosure will be described.

FIG. 19 is a diagram showing a schematic configuration of the air cleaner 100 (electronic device) of the present embodiment. In addition, the arrow in FIG. 19 has shown the flow of the air which the air cleaner 100 took in. As shown in FIG. 19, the air cleaner 100 includes a carbon dioxide absorber 1, a filter 101, and a fan 102.

In addition, in this embodiment, although the case where the carbon dioxide absorption apparatus 1 of Embodiment 1 is provided in the air cleaner 100 is illustrated for convenience of explanation, it replaces with the said carbon dioxide absorption apparatus 1, and is implemented. The

carbon dioxide absorbers

2 and 3 in the

forms

2 and 3 may be provided in the air cleaner 100.

The fan 102 is a blower that takes air into the air purifier 100. The operation of the fan 102 is controlled by a control unit (not shown) provided in the air cleaner 100. However. The operation of the fan 102 may be controlled by the controller 13 of the carbon dioxide absorber 1.

The filter 101 cleans the air taken into the air purifier 100 by the operation of the fan 102. The type of the filter 101 is not particularly limited, and examples include a deodorizing air conditioning filter, a formaldehyde absorbing air conditioning filter, an antibacterial / dust collecting air conditioning filter, and a combination of these filters.

As shown in FIG. 19, when the fan 102 operates and air is taken into the air cleaner 100, the air passes through the filter 101. The air purified by passing through the filter 101 is taken into the carbon dioxide absorber 1.

Subsequently, as described above, the carbon dioxide absorption device 1 detects the CO ₂ concentration of the taken-in air, and controls the CO ₂ absorption rate of the carbon dioxide absorbent 10 according to the CO ₂ concentration. For this reason, the air purifier 100 can send out air that has been cleaned by the filter 101 and whose CO ₂ concentration has been adjusted to an appropriate value by the carbon dioxide absorber 1. Thus, the air cleaner 100 can provide the user with air that is more suitable for the health of the user.

Further, the air purifier 100 operates the fan 102 to perform both (i) intake of air for cleaning air in the filter 101 and (i) intake of air into the carbon dioxide absorber 1. be able to.

In other words, in the air purifier 100, the fan 102 is shared between the filter 101 (member related to the air cleaning function) and the carbon dioxide absorber 1 (member related to the CO ₂ absorption function). Therefore, according to the said structure, compared with the case where a fan is separately provided with respect to each of the filter 101 and the carbon dioxide absorption apparatus 1, the number of parts can be reduced. For this reason, the manufacturing cost of the air cleaner 100 can be reduced.

The filter 101 preferably removes a substance that inhibits the detection of the CO ₂ concentration in the carbon dioxide absorption device 1 (more specifically, the detection unit 14) (hereinafter referred to as a detection inhibitor). The detection inhibitor is, for example, dust in the air.

In this case, in the carbon dioxide absorber 1, the detection unit 14 can detect the CO ₂ concentration with respect to the air from which the detection inhibitor is removed by the filter 101. For this reason, it becomes possible to more accurately detect the CO ₂ concentration by eliminating the influence of the detection inhibitor. In addition, it is possible to prevent a detection inhibition substance from adhering to the detection unit 14 itself, and a reduction in detection accuracy after the detection inhibition substance has adhered. Therefore, the carbon dioxide absorber 1 can adjust the CO ₂ concentration more accurately over a long period of time.

In addition, in this embodiment, although the air cleaner 100 was illustrated as an example of an electronic device, the said electronic device is not limited to this. The electronic device only needs to include the carbon dioxide absorption device according to one embodiment of the present disclosure, and may be a dehumidifier, a humidifier, an air conditioner, or the like, for example.

For example, when the carbon dioxide absorption device 1 is provided in a dehumidifier or a humidifier, it is possible to provide air whose humidity and CO ₂ concentration are adjusted to appropriate values. Moreover, when the carbon dioxide absorption apparatus 1 is provided in the air conditioner, it is possible to provide air whose humidity and CO ₂ concentration are adjusted to appropriate values. Thus, the carbon dioxide absorption device 1 may be provided in various devices that provide a comfortable air environment for the user.
Further, when the carbon dioxide absorption device 1 is mounted on the dehumidifier, when a semiconductor sensor is used as the detection unit 14, it is preferable to provide a dehumidification unit instead of the filter 101 described above. In this case, the air dehumidified in the dehumidifying unit is taken into the carbon dioxide absorption device 1 so that the detection unit 14 (semiconductor sensor) can detect the CO ₂ concentration of the dehumidified air.

In general, the detection accuracy of a gas (eg, CO ₂ ) concentration by a semiconductor sensor is easily affected by moisture (humidity). Therefore, according to this configuration, it is possible to prevent the reliability of CO ₂ concentration detection in the detection unit 14 (semiconductor sensor) from being reduced due to the presence of moisture. Therefore, it is possible to detect the CO ₂ concentration more accurately. Further, it is possible to prevent water vapor from adhering to the detection unit 14 itself.

The carbon dioxide absorption device 1 is preferably used in a space where ventilation can be restricted. This is because when the ventilation is restricted in a space where ventilation can be restricted, the CO ₂ concentration in the air increases due to the CO ₂ contained in human exhalation or the like. Considering this point, it is desirable that the electronic device (for example, the air purifier 100) including the carbon dioxide absorption device 1 is also used in a space where ventilation can be restricted. Therefore, the air cleaner 100 may be used as an in-vehicle air cleaner, for example.

It should be noted that the “space where ventilation can be restricted” means a sealed space, an indoor space where ventilation can be restricted, an indoor space, or an interior space. Or, “Ventilation-restrictable space” means to voluntarily ventilate (open a window, operate a ventilation fan, operate a ventilating device, operate a device such as a vacuum device to create a negative pressure) In other words, the space can be restricted or prohibited.

[Example of software implementation]
The control blocks (particularly the

control units

13, 23, 33) of the carbon dioxide absorbers 1 to 3 may be realized by a logic circuit (hardware) formed in an integrated circuit (IC chip) or the like, or a CPU (Central It may be realized by software using a Processing Unit.

In the latter case, the carbon dioxide absorbers 1 to 3 include a CPU that executes instructions of a program that is software that realizes each function, and a ROM (Read CPU) in which the program and various data are recorded so as to be readable by the computer (or CPU). Only Memory) or a storage device (these are referred to as “recording media”), RAM (Random Access Memory) for expanding the program, and the like. And the objective of this indication is achieved when a computer (or CPU) reads and runs the said program from the said recording medium. As the recording medium, a “non-temporary tangible medium” such as a tape, a disk, a card, a semiconductor memory, a programmable logic circuit, or the like can be used. The program may be supplied to the computer via an arbitrary transmission medium (such as a communication network or a broadcast wave) that can transmit the program. Note that one aspect of the present disclosure can also be realized in the form of a data signal embedded in a carrier wave in which the program is embodied by electronic transmission.

[Summary]
A carbon dioxide absorption device (1) according to aspect 1 of the present disclosure includes a carbon dioxide absorbent (10) that absorbs carbon dioxide contained in a gas from a gas containing moisture and carbon dioxide (CO ₂ ). The carbon dioxide absorbing device provided, wherein the carbon dioxide absorbing material contains tetravalent lithium silicate (Li ₄ SiO ₄ ), holds the carbon dioxide absorbing material and moisture, and holds the moisture. A holding unit (11) that supplies at least a part of the carbon dioxide absorbent to the carbon dioxide absorbent, a supply unit (moisture supply unit 12) that supplies the moisture to the holding unit, and a supply that controls the operation of the supply unit And a control unit (addition amount setting unit 132).

As described above, the inventors have changed the carbon dioxide absorbent containing Li ₄ SiO ₄ by changing the moisture content (eg, moisture content or moisture pH). It was newly found that the amount of CO ₂ absorbed in the absorbent material can be adjusted (controlled).

So, according to said structure, a supply part can supply a water | moisture content to a carbon dioxide absorber via the said holding | maintenance part by supplying a water | moisture content to a holding | maintenance part based on the instruction | indication of a supply control part. That is, since the moisture content in the carbon dioxide absorbent can be arbitrarily set (changed), the amount of CO ₂ absorbed in the carbon dioxide absorbent can be controlled. Therefore, it is possible to control the amount of CO ₂ absorbed in the carbon dioxide absorbent by a carbon dioxide absorber having a simple configuration.

The carbon dioxide absorption device according to aspect 2 of the present disclosure further includes a detection unit (14) that detects the concentration (detection value P1) of the carbon dioxide contained in the gas in the aspect 1, and the supply control unit Depending on the concentration, the amount of moisture supplied from the supply unit to the holding unit may be set.

According to the above configuration, the amount of water supplied to the holding unit (the amount of water added) can be set according to the CO ₂ concentration in the gas, so that the CO ₂ absorption amount is controlled with higher accuracy. It becomes possible.

In the carbon dioxide absorption device according to aspect 3 of the present disclosure, in the aspect 2, the supply control unit uses a first table (151) indicating a correspondence relationship between the concentration and the set value of the amount of moisture. It is preferable to set the amount of water according to the concentration.

According to the above configuration, by using the first table, it is possible to set the amount of water in accordance with the CO ₂ concentration in the gas, is possible to simplify the process of setting the amount of water in the supply controller It becomes possible.

The carbon dioxide absorption device according to aspect 4 of the present disclosure further includes a detection unit that detects the concentration of the carbon dioxide contained in the gas in any one of the aspects 1 to 3, and the supply control unit ( The pH setting unit 232) may set the pH of the water that the supply unit supplies to the holding unit according to the concentration.

According to the arrangement, in accordance with the CO ₂ concentration in the gas, it is possible to set the pH of the water supplied to the holding portion, it is possible to control the CO ₂ absorption amount with higher accuracy.

In the carbon dioxide absorption device according to aspect 5 of the present disclosure, in the aspect 4, the supply control unit uses a second table (251) indicating a correspondence relationship between the concentration and the set value of the pH of the water. It is preferable to set the pH of the water according to the concentration.

According to the above configuration, by using the second table, it is possible to set the pH of the water in accordance with the CO ₂ concentration in the gas, it is possible to simplify the process of setting the pH of the water in the supply controller Become.

The carbon dioxide absorber according to aspect 6 of the present disclosure further includes a detection unit that detects the concentration of the carbon dioxide contained in the gas in any one of the aspects 1 to 5, and the supply control unit includes: When the concentration is not more than a predetermined reference value (DT), it is preferable that the supply unit stops the supply of the water to the holding unit.

As described above, when the CO ₂ concentration in the gas is equal to or less than the reference value, an excessive amount of CO ₂ is contained in the carbon dioxide absorbent in order to prevent wasteful consumption (deterioration) of the carbon dioxide absorbent. It is preferable not to absorb.

Therefore, according to the above configuration, when the CO ₂ concentration in the gas is less than the reference value, by stopping the addition of water with respect to the holding unit, thereby promptly reducing the CO ₂ absorption amount of carbon dioxide absorbent be able to. Therefore, wasteful consumption of the carbon dioxide absorbent can be effectively prevented.

The carbon dioxide absorption device according to aspect 7 of the present disclosure, in any one of the aspects 1 to 6, heats the detection unit that detects the concentration of the carbon dioxide contained in the gas and the holding unit. A heating unit (35) and a heating control unit (333) for controlling the operation of the heating unit are further provided, and the heating control unit holds the holding when the concentration is equal to or lower than a predetermined reference value. It is preferable to operate the heating unit so as to remove at least a part of the moisture held by the unit.

According to the above structure, in the case where the CO ₂ concentration in the gas is less than the reference value, by operating the heating unit, it is possible to quickly lower the CO ₂ absorption amount of the carbon dioxide absorbent. Therefore, wasteful consumption of the carbon dioxide absorbent can be effectively prevented.

The carbon dioxide absorption device according to aspect 8 of the present disclosure is the carbon dioxide absorption device according to aspect 7, in which the supply control unit uses the history of supplying the moisture to the holding unit as the supply history, and the heating control unit has the concentration described above. It is preferable to operate the heating unit when the supply value is equal to or less than the reference value and the supply history exists.

As discussed above, or less CO ₂ concentration reference value in the gas, and, when the supply history is present (i.e., unwanted case described above), the the CO ₂ to this with carbon dioxide absorbent It is considered that the CO ₂ concentration in the gas has already been sufficiently reduced by the absorption. For this reason, in the case of an unnecessary case, it can be said that the necessity to maintain the CO ₂ absorption amount in the carbon dioxide absorbent is particularly low from the viewpoint of preventing wasteful consumption of the carbon dioxide absorbent.

Therefore, according to the above configuration, it is possible to operate the heating unit in the case of unwanted case, to quickly lower the CO ₂ absorption amount of the carbon dioxide absorbent. Therefore, wasteful consumption of the carbon dioxide absorbent can be prevented particularly effectively.

The electronic apparatus (air purifier 100) according to the ninth aspect of the present disclosure preferably includes the carbon dioxide absorption device according to any one of the first to eighth aspects.

According to said structure, there exists an effect similar to the carbon dioxide absorber which concerns on 1 aspect of this indication.

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

[Another expression of the present disclosure]
Note that one embodiment of the present disclosure can also be expressed as follows.

That is, the carbon dioxide absorber according to one embodiment of the present disclosure includes a carbon dioxide absorbent containing Li ₄ SiO ₄ that absorbs carbon dioxide in a gas containing water and low-concentration carbon dioxide, and the above A carbon dioxide absorbent, a moisture holding unit that holds moisture, and a moisture supply unit that supplies moisture to the moisture holding unit are provided.

The carbon dioxide absorption device according to an aspect of the present disclosure further includes a control unit that can control the supply of moisture from the moisture supply unit to the moisture holding unit.

The carbon dioxide absorption device according to one aspect of the present disclosure further includes a detection unit that detects the concentration of carbon dioxide in the air.

In the carbon dioxide absorption device according to one aspect of the present disclosure, the control unit controls the amount of moisture supplied from the moisture supply unit to the moisture holding unit.

Further, in the carbon dioxide absorption device according to one aspect of the present disclosure, the control unit controls the pH of moisture supplied from the moisture supply unit to the moisture holding unit.

In addition, the carbon dioxide absorption device according to one aspect of the present disclosure further includes a heating unit that heats the moisture holding unit.

(Cross-reference of related applications)
This application claims the benefit of priority over the Japanese patent application filed on September 30, 2016: Japanese Patent Application No. 2016-194494, and by referring to it, all of its contents Included in this document.

1, 2, 3 Carbon dioxide absorber 10 Carbon dioxide absorber 11

Holding part

12, 22 Moisture supply part (supply part)
14 detection unit 35 heater 132 addition amount setting unit (supply control unit)
151 1st table 232 pH setting part (supply control part)
251 Second table 333 Heating control unit 100 Air purifier (electronic device)

Claims

A carbon dioxide absorber comprising a carbon dioxide absorbent that absorbs carbon dioxide contained in the gas from a gas containing moisture and carbon dioxide,
The carbon dioxide absorbent contains tetravalent lithium silicate,
A holding unit that holds the carbon dioxide absorbent and moisture, and supplies at least a part of the retained moisture to the carbon dioxide absorbent;
A supply unit for supplying the moisture to the holding unit;
And a supply control unit that controls the operation of the supply unit.
A detector that detects the concentration of the carbon dioxide contained in the gas;
The carbon dioxide absorption device according to claim 1, wherein the supply control unit sets the amount of the water that the supply unit supplies to the holding unit according to the concentration.
The said supply control part sets the said quantity of the water | moisture content according to the said density | concentration using the 1st table which shows the corresponding | compatible relationship between the said density | concentration and the setting value of the said quantity of the water | moisture content. The carbon dioxide absorption device described.
A detector that detects the concentration of the carbon dioxide contained in the gas;
The said supply control part sets pH of the said water | moisture content which the said supply part supplies with respect to the said holding | maintenance part according to the said density | concentration, The dioxide dioxide of any one of Claim 1 to 3 characterized by the above-mentioned. Carbon absorber.
The said supply control part sets the pH of the said water | moisture content according to the said density | concentration using the 2nd table which shows the corresponding | compatible relationship between the said density | concentration and the set value of the pH of the said water | moisture content. The carbon dioxide absorption device described.
A detector that detects the concentration of the carbon dioxide contained in the gas;
The said supply control part makes the said supply part stop supply of the said water | moisture content to the said holding | maintenance part, when the said density | concentration is below a predetermined reference value, The any one of Claim 1 to 5 characterized by the above-mentioned. The carbon dioxide absorber described in 1.
A detection unit for detecting the concentration of the carbon dioxide contained in the gas;
A heating unit for heating the holding unit;
A heating control unit for controlling the operation of the heating unit,
The said heating control part operates the said heating part so that at least one part of the said water | moisture content which the said holding | maintenance part hold | maintains may be removed when the said density | concentration is below a predetermined reference value. The carbon dioxide absorption device according to any one of 1 to 6.
As a supply history, a history of the supply unit supplying the moisture to the holding unit,
The carbon dioxide absorption device according to claim 7, wherein the heating control unit operates the heating unit when the concentration is equal to or lower than the reference value and the supply history exists. .
An electronic apparatus comprising the carbon dioxide absorber according to any one of claims 1 to 8.