Carbon dioxide recovery system

Abstract

To provide a carbon dioxide recovery system capable of heating an absorber uniformly and maintaining a temperature of the absorber within a predetermined temperature range.SOLUTION: A carbon dioxide recovery system 1 heats an absorber 102a that has absorbed carbon dioxide and desorbs and recovers the carbon dioxide from the absorber 102a. The carbon dioxide recovery system 1 includes: a module accommodation body 10 that accommodates a carbon dioxide collection module 101 including the absorber 102a; a light collection section 20 that collects sunlight to heat the module accommodation body 10; a recovery section 30 that recovers the carbon dioxide desorbed from the absorber 102a; and a sunlight regulation section 50 that can change at least one of the light collection section 20 and the module accommodation body 10 into a shielding state for shielding emitted sunlight and a transmission state for transmitting the sunlight.SELECTED DRAWING: Figure 2

Description

[Technical field]

[0001] The present invention relates to a carbon dioxide capture system. [Background technology]

[0002] As a method for capturing carbon dioxide, a chemical absorption method using an aqueous solution of an amine compound (hereinafter, referred to as an "amine aqueous solution") as an absorbing liquid is known. For example, Patent Document 1 discloses a carbon dioxide separation and capture method in which carbon dioxide is captured by an amine aqueous solution.

[0003] The carbon dioxide separation and recovery method of Patent Document 1 includes an absorption step of contacting a mixed gas containing carbon dioxide with the amine aqueous solution to absorb carbon dioxide into the amine aqueous solution, and a thermal regeneration step of heating the amine aqueous solution having absorbed carbon dioxide to a temperature higher than that in the absorption step to desorb and recover the absorbed carbon dioxide, thereby regenerating the amine aqueous solution. The upper limit of the temperature of the amine aqueous solution in the thermal regeneration step is preferably 160° C. or lower.

[0004] The carbon dioxide capture method disclosed in Patent Document 1 requires a lot of energy to heat the absorbent such as the amine aqueous solution to desorb carbon dioxide. For this reason, a thermal regeneration device that uses electric power to heat the absorbent is not preferable because it generates electric power to desorb carbon dioxide from the absorbent that has captured the carbon dioxide, resulting in the emission of carbon dioxide. Therefore, a thermal regeneration device that uses a trough-type solar heat collector that utilizes sunlight, which is a natural energy source, as disclosed in Patent Document 2, to heat the absorbent that has absorbed carbon dioxide, is considered. [Prior art documents] [Patent documents]

[0005] [Patent Document 1] JP 2017-104775 A [Patent Document 2] JP 2015-010748 A Summary of the Invention [Problem to be solved by the invention]

[0006] The duration of sunlight, the position of irradiation, the amount of irradiation, etc. of sunlight change depending on the date, time, weather, etc. Therefore, in a thermal regeneration device using sunlight, the thermal energy transferred to the absorbent fluctuates. Therefore, it is difficult for the thermal regeneration device to heat the absorbent uniformly. Furthermore, it is difficult for the thermal regeneration device to maintain the temperature of the absorbent within a predetermined temperature range. Therefore, there is a demand for a carbon dioxide capture system that can heat the absorbent uniformly and maintain the temperature of the absorbent within a predetermined temperature range.

[0007] An object of the present invention is to provide a carbon dioxide capture system capable of uniformly heating an absorbent material and maintaining the temperature of the absorbent material within a predetermined temperature range. [Means for solving the problem]

[0008] The present inventors have studied a carbon dioxide capture system capable of uniformly heating an absorbent and maintaining the temperature of the absorbent at a constant level. As a result of intensive studies, the present inventors have come up with the following configuration.

[0009] A carbon dioxide capture system that heats an absorbent that has absorbed carbon dioxide, and captures the carbon dioxide by desorbing it from the absorbent. The carbon dioxide capture system includes a module housing that houses a carbon dioxide capture module including the absorbent, a light collecting unit that collects sunlight and heats the module housing, a capture unit that captures the carbon dioxide desorbed from the absorbent, and a sunlight adjustment unit that can be changed between a blocking state that blocks sunlight irradiated to at least one of the light collecting unit and the module housing, and a transmitting state that transmits the sunlight.

[0010] The module housing of the carbon dioxide capture system having the above-mentioned configuration is heated by sunlight when the sunlight adjustment unit is changed to a transmitting state. Also, the module housing is not heated by sunlight when the sunlight adjustment unit is changed to a blocking state. Therefore, the carbon dioxide capture system can change the amount of sunlight irradiated onto at least one of the collector and the module housing by the sunlight adjustment unit. In other words, the carbon dioxide capture system can adjust the heating state of the absorbent contained in the carbon dioxide capture module in the module housing by changing the adjustment state of the sunlight adjustment unit according to the amount of sunlight irradiated, which varies depending on the date, time, weather, etc. This makes it possible to heat the absorbent uniformly and maintain the temperature of the absorbent within a predetermined temperature range.

[0011] From another viewpoint, it is preferable that the carbon dioxide capture system of the present invention includes the following configuration. The carbon dioxide capture system has a temperature detection unit that detects the temperature of the module housing, and a control unit that controls a state of the sunlight adjustment unit. The control unit changes the adjustment state of the sunlight adjustment unit between the blocking state and the transmitting state based on the temperature of the module housing detected by the temperature detection unit.

[0012] The control unit of the carbon dioxide capture system having the above-mentioned configuration changes the adjustment state of the sunlight adjustment unit to approach the shielding state when the temperature of the module housing detected by the temperature detection unit is higher than the target temperature range. Also, the control unit changes the adjustment state of the sunlight adjustment unit to approach the transmitting state when the temperature of the module housing detected by the temperature detection unit is lower than the target temperature range. In other words, when the temperature of the module housing fluctuates due to fluctuations in the amount of sunlight irradiation, the carbon dioxide capture system changes the adjustment state of the sunlight adjustment unit based on the temperature of the module housing. Therefore, the carbon dioxide capture system can adjust the heating state of the absorbent contained in the carbon dioxide capture module in the module housing even when heated by unstable sunlight. This makes it possible to heat the absorbent uniformly and maintain the temperature of the absorbent within a predetermined temperature range.

[0013] From another viewpoint, it is preferable that the carbon dioxide capture system of the present invention includes the following configuration. The carbon dioxide capture system has an exterior body that houses the module housing, and the heat medium that is located between the module housing and the exterior body and covers the module housing. The temperature detection unit detects the temperature of the module housing via the heat medium. The control unit changes the adjustment state of the sunlight adjustment unit between the blocking state and the transmitting state based on the temperature of the module housing detected by the temperature detection unit.

[0014] The module housing of the carbon dioxide capture system having the above-mentioned configuration is heated by the energy of sunlight via the heat medium. The heat medium transfers heat from the portion heated by irradiation with sunlight to the entire heat medium by thermal conduction and convection. The module housing is uniformly heated by the heat medium whose temperature has risen almost uniformly throughout. The carbon dioxide capture system also changes the adjustment state of the sunlight adjustment unit based on the temperature of the heat medium in the exterior body. Thus, the heat medium in the exterior body is maintained within a predetermined temperature range. The heat medium in the exterior body is maintained below a predetermined upper limit temperature, for example. The module housing is heated within a predetermined temperature range by the heat medium maintained within a predetermined temperature range. This makes it possible to heat the absorbent uniformly and maintain the temperature of the absorbent within a predetermined temperature range.

[0015] From another viewpoint, it is preferable that the carbon dioxide capture system of the present invention includes the following configuration: The sunlight adjustment unit is a light control member that is positioned so as to cover the reflective surface of the light collecting unit or the module housing, and is changeable between the blocking state and the transmitting state by applying a voltage.

[0016] The dimming member of the carbon dioxide capture system having the above-mentioned configuration is configured to be able to change the transmittance of sunlight based on the value of the applied voltage. In other words, the carbon dioxide capture system can arbitrarily adjust the amount of sunlight irradiated onto the reflective surface of the light collector or the module housing by the dimming member included in the sunlight adjustment unit. Furthermore, the carbon dioxide capture system can adjust the amount of sunlight irradiated with a space-saving configuration without providing a mechanical mechanism for blocking sunlight. Therefore, the amount of sunlight irradiated onto the module housing is maintained within a certain range even if the amount of sunlight irradiated fluctuates. This makes it possible to uniformly heat the absorbent material and maintain the temperature of the absorbent material within a predetermined temperature range.

[0017] From another viewpoint, the carbon dioxide capture system of the present invention preferably includes the following configuration: The sunlight adjustment unit has a plurality of plate-like members positioned so as to cover at least one of the light collecting unit and the module housing. Each of the plate-like members is configured to be rotatable about an axis extending in a direction perpendicular to the thickness direction, and by rotating the plurality of plate-like members, the adjustment state of the sunlight adjustment unit can be changed between the blocking state and the transmitting state.

[0018] The sunlight adjustment unit of the carbon dioxide capture system having the above-mentioned configuration can change the gap between adjacent plate-like members by changing the rotation angle of the multiple plate-like members. In other words, the carbon dioxide capture system can arbitrarily adjust the amount of sunlight irradiated to at least one of the light collector and the module housing by the multiple plate-like members included in the sunlight adjustment unit. Therefore, the amount of sunlight irradiated to the module housing is maintained within a certain range even if the amount of sunlight irradiated fluctuates. This makes it possible to uniformly heat the absorbent material and maintain the temperature of the absorbent material within a predetermined temperature range.

[0019] From another viewpoint, it is preferable that the carbon dioxide capture system of the present invention includes the following configuration: The sunlight adjustment unit has a shading member positioned so as to cover the light collecting unit and the module housing. The shading member is configured to be movable with respect to the light collecting unit or the module housing, and by moving the shading member, the adjustment state of the sunlight adjustment unit can be changed between the shading state and the transmitting state.

[0020] The sunlight adjustment unit of the carbon dioxide capture system having the above-mentioned configuration is configured to be able to switch the shading member between a shielding state position that shields the sunlight irradiated to the concentrating unit and the module housing, and a transparent state position that does not shield the sunlight irradiated to the concentrating unit and the module housing. In other words, the carbon dioxide capture system can adjust the amount of sunlight irradiated by the shading member included in the sunlight adjustment unit. Therefore, the amount of sunlight irradiated to the module housing is maintained within a certain range even if the amount of sunlight irradiated fluctuates. This makes it possible to uniformly heat the absorbent material and maintain the temperature of the absorbent material within a predetermined temperature range.

[0021] From another viewpoint, it is preferable that the carbon dioxide capture system of the present invention includes the following configuration. The carbon dioxide capture system has a plurality of the light collecting sections and a plurality of the module housings. The sunlight adjustment section has a plurality of plate-like members positioned to cover the plurality of the light collecting sections and the plurality of the module housings. Each of the plate-like members is configured to be rotatable about an axis extending in a direction perpendicular to the thickness direction, and by rotating the plurality of plate-like members, the adjustment state of the sunlight adjustment section can be changed between the blocking state and the transmitting state.

[0022] The sunlight adjustment unit of the carbon dioxide capture system having the above-mentioned configuration can change the gap between adjacent plate-like members by changing the rotation angle of the multiple plate-like members. In other words, the carbon dioxide capture system can arbitrarily adjust the amount of sunlight irradiated onto the multiple light collectors and the multiple module housings by the multiple plate-like members included in the sunlight adjustment unit. Therefore, the amount of sunlight irradiated onto the multiple module housings is maintained within a certain range even if the amount of sunlight irradiated fluctuates. This makes it possible to uniformly heat the multiple absorbents and maintain the temperature of the multiple absorbents within a predetermined temperature range. Effect of the Invention

[0023] According to one embodiment of the present invention, the absorbent material can be heated uniformly and the temperature of the absorbent material can be maintained within a predetermined range. [Brief description of the drawings]

[0024] [Figure 1] FIG. 1 is a schematic diagram of a carbon dioxide capture system according to a first embodiment of the present invention. [Diagram 2] FIG. 2 is a cross-sectional view in the axial direction of the module housing in the light collecting unit and the sunlight adjusting unit that heats the module housing in the carbon dioxide capture system according to the first embodiment of the present invention. [Diagram 3] FIG. 3 is a control block diagram of the carbon dioxide capture system according to the first embodiment of the present invention. [Figure 4] FIG. 4 is a schematic diagram showing a transmission state of a sunlight adjusting section in the carbon dioxide capture system according to the first embodiment of the present invention. [Diagram 5] FIG. 5 is a schematic diagram showing a shaded state of the sunlight adjustment unit in the carbon dioxide capture system according to the first embodiment of the present invention. [Figure 6] FIG. 6 is a perspective view showing a carbon dioxide capture module. [Figure 7] FIG. 7 is an axial cross-sectional view of a carbon dioxide capture module. [Figure 8] FIG. 8 is a diagram showing a flowchart of carbon dioxide capture control in the carbon dioxide capture system according to the first embodiment of the invention. [Figure 9] FIG. 9 is a cross-sectional view in the axial direction of the module housing in a light collecting unit that heats the module housing of a carbon dioxide capture system according to a second embodiment of the present invention and a sunlight adjusting unit in a transmitting state. [Figure 10] FIG. 10 is a cross-sectional view in the axial direction of the module housing in a light collecting unit that heats the module housing in a carbon dioxide capture system according to a second embodiment of the present invention and a sunlight adjusting unit in a shielded state. [Figure 11]FIG. 11 is a cross-sectional view in the axial direction of the module housing in a plurality of light collecting units that heat a plurality of module housings in a carbon dioxide capture system according to a first modification of the second embodiment of the present invention and a sunlight adjustment unit in a transmitting state. [Figure 12] FIG. 12 is a cross-sectional view in the axial direction of the module housing in a light collecting unit that heats the module housing and a sunlight adjusting unit in a transmitting state in a carbon dioxide capture system according to a second modification of the second embodiment of the present invention. [Figure 13] FIG. 13 is a cross-sectional view in the axial direction of the module housing in a light collecting unit that heats the module housing in a carbon dioxide capture system according to a second modification of the second embodiment of the present invention and a sunlight adjusting unit in a shielded state. [Figure 14] FIG. 14 is a cross-sectional view in the axial direction of the module housing in a light collecting unit and a sunlight adjusting unit that heats the module housing in a carbon dioxide capture system according to a third embodiment of the present invention. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0025] Each embodiment will be described below with reference to the drawings. In each drawing, the same parts are given the same reference numerals, and the description of the same parts will not be repeated. Note that the dimensions of the components in each drawing do not faithfully represent the actual dimensions of the components and the dimensional ratios of each component.

[0026] In addition, in the following description, the expressions "fix," "connect," "join," "attach," and the like (hereinafter referred to as "fixation, etc.") include not only cases where members are directly fixed, etc. to each other, but also cases where members are fixed, etc. via other members. In other words, in the following description, the expression "fixation, etc." includes the meaning of direct and indirect fixation, etc. of members to each other.

[0027] [Embodiment 1] <Configuration of carbon dioxide capture system> A schematic configuration of a carbon dioxide capture system 1 according to a first embodiment of the carbon dioxide capture system of the present invention will be described with reference to Fig. 1 to Fig. 5. Fig. 1 is a schematic diagram of the carbon dioxide capture system 1 according to the first embodiment of the present invention. Fig. 2 is a cross-sectional view showing a heating state of a carbon dioxide capture module 101 by the carbon dioxide capture system 1. Fig. 3 is a control block diagram of the carbon dioxide capture system 1. Fig. 4 is a schematic diagram showing a transmitting state of a sunlight adjustment unit 50 in the carbon dioxide capture system 1. Fig. 5 is a schematic diagram showing a shielding state of a sunlight adjustment unit 50 in the carbon dioxide capture system 1.

[0028] The carbon dioxide capture system 1 is a system that desorbs carbon dioxide captured by a carbon dioxide capture module 101. The carbon dioxide capture module 101 is placed in a living space such as the interior of an ordinary home, and captures a small amount of carbon dioxide contained in the surrounding air by an absorbent material.

[0029] As shown in FIG. 1, the carbon dioxide capture system 1 has a module housing 10, a light collecting unit 20, a capture unit 30, a temperature detection unit 40, a sunlight adjustment unit 50, and a control unit 60.

[0030] The module housing 10 is a container that houses the carbon dioxide capture module 101. The module housing 10 has a housing section 11 that can house the entire carbon dioxide capture module 101. The housing section 11 is configured to be able to be sealed. The module housing 10 is configured, for example, in a cylindrical shape. The module housing 10 is made of a metal such as copper, brass, stainless steel, or aluminum that has good thermal conductivity. A solar light absorbing layer (not shown) made of a black metal film or the like is formed on the surface of the module housing 10. The module housing 10 can absorb solar light by the solar light absorbing layer and efficiently heat the carbon dioxide capture module 101. Note that, instead of the solar light absorbing layer, the module housing 10 may have an outer surface of the module housing 10 roughened to suppress reflection, thereby increasing the solar light absorption efficiency.

[0031] As shown in FIG. 1 and FIG. 2, the light collecting unit 20 is configured as a light collecting device that collects sunlight and heats the module housing 10. The light collecting unit 20 has a concave mirror 21. The concave mirror 21 has a shape obtained by dividing a cylinder into two in the axial direction, for example. The concave mirror 21 is positioned so as to surround the module housing 10 with its axial direction aligned with the axial direction of the module housing 10. In other words, the module housing 10 is positioned inside the concave mirror 21. The light collecting unit 20 is configured to collect sunlight onto the module housing 10 by the concave mirror 21. In addition, the light collecting unit 20 is configured so that the position of the concave mirror 21 can be changed by a driving device (not shown) so as to collect the sunlight of a moving sun onto the module housing 10.

[0032] 1, the capture unit 30 captures the carbon dioxide desorbed from the carbon dioxide capture module 101. The capture unit 30 has a carbon dioxide capture tank 31, an exhaust pump 32, an exhaust pipe 33, and a carbon dioxide concentration meter .

[0033] The carbon dioxide capture tank 31 stores carbon dioxide. The carbon dioxide capture tank 31 is configured to be able to seal the carbon dioxide.

[0034] The exhaust pump 32 exhausts carbon dioxide within the accommodation section 11 of the module accommodation body 10 to the carbon dioxide capture tank 31. The exhaust pump 32 is configured to be able to suck in carbon dioxide from within the accommodation section 11 via an exhaust pipe 33. The exhaust pump 32 is also configured to be able to discharge carbon dioxide to the carbon dioxide capture tank 31 via the exhaust pipe 33.

[0035] The carbon dioxide concentration meter 34 detects the concentration of carbon dioxide in the storage unit 11. The carbon dioxide concentration meter 34 is located in the storage unit 11. The carbon dioxide concentration meter 34 detects the concentration of carbon dioxide desorbed from the carbon dioxide capture module 101. It is noted that the carbon dioxide capture system 1 does not have to detect the concentration of carbon dioxide desorbed from the carbon dioxide capture module 101. The carbon dioxide capture system 1 may be configured to end the carbon dioxide capture control based on the heating time of the carbon dioxide capture module 101.

[0036] The temperature detection unit 40 detects the temperature of the module housing 10. The temperature detection unit 40 includes a thermometer 41. The thermometer 41 is located inside the housing unit 11. The thermometer 41 is located, for example, at an upper portion of the housing unit 11. Thus, the thermometer 41 is configured to detect the temperature at the upper portion inside the housing unit 11.

[0037] As shown in Figs. 1 and 2, the sunlight adjustment unit 50 adjusts the amount of sunlight irradiated onto the module housing 10. The sunlight adjustment unit 50 includes a dimming member 51. The dimming member 51 adjusts the amount of sunlight irradiated by, for example, a PDLC film. The PDLC film is a liquid crystal film that can be changed between a transmitting state that transmits sunlight and a blocking state that blocks sunlight by controlling the orientation of the liquid crystal molecules. The PDLC film can change the transmittance of sunlight depending on the value of the applied voltage. In other words, the PDLC film can change the transmittance steplessly from the transmitting state to the blocking state.

[0038] The light control member 51 is positioned so as to cover at least a portion of the reflective surface of the concave mirror 21 that faces the module housing 10. For example, the light control member 51 changes the transmittance to 10% or less in the blocking state. For example, the light control member 51 changes the transmittance to 90% or more in the transmitting state. Thus, the light control member 51 can change the transmittance of sunlight through the concave mirror 21 from a blocking state where the transmittance is 10% or less to a transmitting state where the transmittance is 90% or more.

[0039] 1 and 3, the control unit 60 controls the exhaust pump 32, the drive device of the light collecting unit 20, and the dimming member 51. The control unit 60 is substantially composed of a CPU, a ROM, a RAM, a HDD, etc., connected via a bus. Alternatively, the control unit 60 is composed of a one-chip LSI, etc. The control unit 60 stores various programs and data for controlling the operations of the exhaust pump 32, the drive device of the light collecting unit 20, the dimming member 51, etc.

[0040] The control unit 60 is electrically connected to the exhaust pump 32, the carbon dioxide concentration meter 34, the drive device of the light collecting unit 20, the thermometer 41, and the sunlight adjustment unit 50. The control unit 60 can send a start signal and a stop signal to the exhaust pump 32. The control unit 60 can send a position signal to the drive device of the light collecting unit 20 to change the position of the concave mirror 21 based on the date and time. The control unit 60 can send a light control signal to the light adjusting member 51 to change the transmittance of the light adjusting member 51 between the transmittance in the transmitting state and the transmittance in the blocked state based on the temperature of the module housing 10 detected by the thermometer 41.

[0041] The control unit 60 can obtain a signal related to the concentration of carbon dioxide in the housing unit 11 from the carbon dioxide concentration meter 34. The control unit 60 can obtain a signal related to the temperature of the module housing body 10 from the thermometer 41.

[0042] <Sunlight adjustment of the solar control unit> Next, adjustment of sunlight by the sunlight adjustment unit 50 will be described with reference to FIG. 4 and FIG.

[0043] 4, the concave mirror 21 concentrates the sunlight that has passed through the light adjusting member 51 onto the module container 10. Therefore, the light adjusting member 51 can adjust the amount of sunlight irradiated onto the concave mirror 21.

[0044] When the temperature of the module housing 10 is increased, the light control member 51 is adjusted to a transmissive state that transmits sunlight. When the transmittance of the light control member 51 is 90% or more, the concave mirror 21 concentrates 90% or more of the sunlight irradiated from the sun onto the module housing 10. Therefore, heating of the module housing 10 by sunlight is promoted.

[0045] 5, when the temperature of the module housing 10 is decreased, the light control member 51 is adjusted to a shielding state in which it shields sunlight. When the transmittance of the light control member 51 is 10% or less, the concave mirror 21 concentrates 10% or less of the sunlight irradiated from the sun onto the module housing 10. Therefore, the module housing 10 is prevented from being heated by sunlight.

[0046] The light-adjusting member 51 can change the transmittance between the transmittance in the shielded state and the transmittance in the transmitted state according to the temperature of the module housing 10. When the temperature of the module housing 10 is maintained within a target temperature range, the light-adjusting member 51 is adjusted by the control unit 60 so that the transmittance decreases when the temperature of the module housing 10 rises above the target temperature range (see FIG. 5). The light-adjusting member 51 is adjusted by the control unit 60 so that the transmittance returns to the original transmittance when the temperature of the module housing 10 falls to the target temperature range. The light-adjusting member 51 is adjusted by the control unit 60 so that the transmittance increases when the temperature of the module housing 10 falls below the target temperature range (see FIG. 4). The light-adjusting member 51 is adjusted by the control unit 60 so that the transmittance returns to the original transmittance when the temperature of the module housing 10 rises to the target temperature range.

[0047] <Configuration of carbon dioxide capture module> Next, a schematic configuration of the carbon dioxide trapping module 101 will be described with reference to Fig. 6 and Fig. 7. Fig. 6 is a perspective view showing the carbon dioxide trapping module 101. Fig. 7 is a cross-sectional view of the carbon dioxide trapping module 101 in the axial direction.

[0048] 6, the carbon dioxide trapping module 101 has a substantially cylindrical outer shape. The carbon dioxide trapping module 101 has a cylindrical absorption section 102, a pair of cylindrical filter sections 103, and a sealing section 104.

[0049] 7, the absorbing section 102 is made of a rectangular sheet-like member that is long in one direction. The absorbing section 102 includes an absorbent 102a that absorbs carbon dioxide in the air.

[0050] The filter portion 103 allows air to pass through but prevents air from passing through the absorbent material 102a.

[0051] The absorbing section 102 is configured by impregnating a base material with an absorbent 102a that absorbs carbon dioxide. The absorbent 102a is, for example, an amine-based absorbent that absorbs carbon dioxide. The base material is, for example, a sheet-like sponge made of polyurethane, melamine resin, or the like. The sheet-like sponge may be, for example, an activated carbon filter to which activated carbon is attached.

[0052] Examples of amine-based absorbents that absorb carbon dioxide include monoethanolamine, diethanolamine, triethanolamine, 2-amino-2-methyl-1-propanol, 2-isopropylaminoethanol, 2-(methylamino)ethanol, 2-(ethylamino)ethanol, N-methyldiethanolamine, ethylenediamine, hexamethylenediamine, diethylenetriamine, piperazine, o-xylylenediamine, m-xylylenediamine, p-xylylenediamine, and isophoronediamine, and may be mixtures thereof. These amines may be mixed with a liquid such as ethylene glycol that has a high boiling point and a molecular diameter of 4 Å or more that does not pass through the filter unit 103. When using the amine-based absorbent as a mixture, it is preferable that the concentration of the liquid amine-based absorbent is 30% or more.

[0053] Furthermore, as the amine-based absorbent, a polymeric amine having a number average molecular weight of 500 or more, or a polymer of an amine monomer and a dicarboxylic acid monomer, the number average molecular weight of which is 500 or more, may be used.

[0054] Such high molecular weight amines do not volatilize like ethanolamine, which is a low molecular weight amine, so there is no need to block the permeation of the volatilized amine-based absorbent in filter section 103. For this reason, filter section 103 may have a lower performance in blocking gas permeation compared to a filter that can block the permeation of volatilized amine-based absorbent, and therefore allows air to pass through more easily.

[0055] As the polymeric amine, for example, polyethyleneimine is preferable, and the number average molecular weight is preferably from 10,000 to 100,000. The polyethyleneimine may be a branched polyethyleneimine which is a liquid, or a linear polyethyleneimine which is a solid.

[0056] If the number average molecular weight of the liquid polyethyleneimine exceeds 100,000, the viscosity becomes too high and handling becomes difficult. However, by setting the upper limit of the number average molecular weight of the polyethyleneimine to 100,000, it is possible to prevent the handling from becoming difficult.

[0057] The liquid absorbent 102a is, for example, monoethanolamine. The absorbent 102a may be an amine-based compound capable of absorbing carbon dioxide. The amine-based compound absorbent 102a has a large absorption rate of carbon dioxide at room temperature. Therefore, by using an amine-based compound as the absorbent 102a, the speed of capturing carbon dioxide at room temperature can be improved.

[0058] The filter portion 103 is made of a material that allows air to pass through but does not allow the absorbent material 102a to pass through. As a constituent material of the filter portion 103, for example, a film-like or sheet-like porous resin such as a polyolefin-based porous film or a PTFE (polytetrafluoroethylene) porous film can be used.

[0059] The filter section 103 may have a filter body made of a film-like or sheet-like porous resin, and a support supporting the filter body. In this case, the support is preferably disposed in close contact with the surface opposite to the surface on which the absorbing section 102 is disposed, among both surfaces in the thickness direction of the filter body. The support may be deformed into a roll shape and may be made of a material that is permeable to air.

[0060] The operation of the absorbing section 102 and the filter section 103 when the absorbing section 102 is surrounded by the filter section 103 will be described. Air containing nitrogen (N2), oxygen (O2), carbon dioxide (CO2), etc., passes through the filter section 103 and reaches the absorbing section 102. Carbon dioxide (CO2) contained in the air that reaches the absorbing section 102 is absorbed by the absorbent 102a impregnated in the absorbing section 102. Air containing nitrogen (N2), oxygen (O2), etc. other than carbon dioxide (CO2) passes through the filter section 103 without being absorbed by the absorbent 102a. In this way, a small amount of carbon dioxide (CO2) contained in the air that passes through the filter section 103 is captured by the absorbent 102a of the absorbing section 102.

[0061] The filter section 103 prevents the permeation of amines constituting the liquid amine-based absorbent impregnated in the absorption section 102. Thus, the amines are trapped in the absorption section 102 by the filter section 103 surrounding the absorption section 102. Therefore, the harmful amine-based absorbent in the absorption section 102 does not leak out of the carbon dioxide capture module 101.

[0062] The carbon dioxide captured by the absorbent 102a is desorbed from the absorbent 102a by heating it to, for example, about 120°C by the carbon dioxide capture system 1. The higher the heating temperature of the absorbent 102a, the more efficient the carbon dioxide desorption. However, since the higher the heating temperature, the more the absorbent 102a deteriorates, it is preferable to heat the absorbent 102a within a predetermined temperature range, the upper limit of which is, for example, 90°C.

[0063] The sealing portion 104 covers the peripheral ends in the axial direction of the absorbing portion 102 and the filter portion 103. The sealing portion 104 blocks the absorbing portion 102 from contacting the surrounding air other than the air passing through the filter portion 103. In other words, the absorbing portion 102, including the peripheral ends, is not exposed to the outside. As a result, the filter portion 103 prevents the absorbing material 102a of the absorbing portion 102 from leaking to the outside.

[0064] <Carbon dioxide capture and control> Next, carbon dioxide capture control of the carbon dioxide capture system 1 according to the present invention will be specifically described with reference to Fig. 8. Fig. 8 is a diagram showing a flowchart of carbon dioxide capture control of the carbon dioxide capture system 1. In addition, in the module housing 10 of the carbon dioxide capture system 1, two carbon dioxide capture modules 101 are sealed in a state where they are stacked in the axial direction.

[0065] 8, in step S110 of the carbon dioxide capture control, the control unit 60 transmits a position signal to the light collecting unit 20 to adjust the position of the concave mirror 21. The control unit 60 shifts the step to step S120. As a result, the carbon dioxide capture system 1 starts heating the module housing 10 with sunlight.

[0066] In step S120, the control unit 60 acquires information relating to the temperature T1 inside the housing unit 11 in the module housing body 10 from the temperature detection unit 40. The control unit 60 shifts the step to step S130.

[0067] In step S130, the control unit 60 transmits a start signal to the exhaust pump 32. The control unit 60 shifts the step to step S140. As a result, the carbon dioxide capture system 1 starts capturing the carbon dioxide in the storage unit 11.

[0068] In step S140, the control unit 60 determines whether or not the temperature T1 in the housing section 11 in the module housing 10 is equal to or lower than the upper limit temperature TH, based on information related to the temperature T1 in the housing section 11 in the module housing 10 acquired from the temperature detection unit 40. As a result, when it is determined that the temperature T1 in the housing section 11 in the module housing 10 is equal to or lower than the upper limit temperature TH, the control unit 60 shifts the step to step S150. On the other hand, when it is determined that the temperature T1 in the housing section 11 in the module housing 10 is not equal to or lower than the upper limit temperature TH, the control unit 60 shifts the step to step S250.

[0069] In step S150, the control unit 60 determines whether or not the carbon dioxide concentration C1 in the module housing 10 obtained from the carbon dioxide concentration meter 34 has continued to be less than the reference concentration C0 for a predetermined time. As a result, if it is determined that the carbon dioxide concentration C1 in the module housing 10 has continued to be less than the reference concentration C0 for the predetermined time, the control unit 60 shifts the step to step S160. On the other hand, if it is determined that the carbon dioxide concentration C1 in the module housing 10 has not continued to be less than the reference concentration C0 for the predetermined time, the control unit 60 shifts the step to step S140.

[0070] In step S160, the control unit 60 transmits a stop signal to the exhaust pump 32. The control unit 60 ends the carbon dioxide capture control.

[0071] In step S250, the control unit 60 transmits a light control signal to the light control member 51 to reduce the transmittance. The control unit 60 shifts the step to step S260. As a result, the carbon dioxide capture system 1 starts controlling the amount of sunlight irradiation by the light control member 51.

[0072] In step S260, the control unit 60 determines whether or not the temperature T1 in the housing section 11 in the module housing 10 is equal to or lower than the upper limit temperature TH, based on information related to the temperature T1 in the housing section 11 in the module housing 10 acquired from the temperature detection unit 40. As a result, when it is determined that the temperature T1 in the housing section 11 in the module housing 10 is equal to or lower than the upper limit temperature TH, the control unit 60 shifts the step to step S270. On the other hand, when it is determined that the temperature T1 in the housing section 11 in the module housing 10 is not equal to or lower than the upper limit temperature TH, the control unit 60 shifts the step to step S260.

[0073] In step S270, the control unit 60 transmits a light control signal to increase the transmittance to the light control member 51. The control unit 60 shifts the step to step S140. As a result, the carbon dioxide capture system 1 stops suppressing the amount of sunlight irradiation by the light control member 51.

[0074] The carbon dioxide capture system 1 having the above-mentioned configuration promotes heating of the module housing 10 by sunlight when the light-adjusting member 51 of the sunlight adjustment unit 50 is changed to the transmitting state. Moreover, the carbon dioxide capture system 1 suppresses heating of the module housing 10 by sunlight when the light-adjusting member 51 is changed to the blocking state.

[0075] The light-adjusting member 51 is configured to be able to change the transmittance of sunlight based on the value of the applied voltage. That is, the carbon dioxide capture system 1 can arbitrarily adjust the amount of sunlight irradiated onto the reflective surface of the light collector 20 or the module housing 10 by the light-adjusting member 51 included in the sunlight adjustment unit 50. Furthermore, by employing the sheet-like light-adjusting member 51, the carbon dioxide capture system 1 can adjust the amount of sunlight irradiated with a space-saving configuration without providing a mechanical mechanism for blocking sunlight.

[0076] When the temperature of the module housing 10 detected by the temperature detection unit 40 is higher than the target temperature range, the control unit 60 changes the adjustment state of the sunlight adjustment unit 50, for example, to approach the shielding state. When the temperature of the module housing 10 detected by the temperature detection unit 40 is lower than the target temperature range, the control unit 60 changes the adjustment state of the sunlight adjustment unit 50, for example, to approach the transmission state. At this time, the amount of sunlight irradiated on the module housing 10 is maintained within a certain range even if the date, time, weather, etc. change. Therefore, the carbon dioxide capture system 1 can adjust the heating state of the absorbent 102a included in the carbon dioxide capture module 101 in the module housing 10 even when heated by unstable sunlight. This makes it possible to uniformly heat the absorbent 102a and maintain the temperature of the absorbent 102a within a predetermined temperature range.

[0077] [Embodiment 2] Next, a carbon dioxide capture system 1A according to a second embodiment of the carbon dioxide capture system of the present invention will be described with reference to Figs. 9 and 10. Fig. 9 is a cross-sectional view in the axial direction of the module housing 10 in the sunlight adjustment unit 50A in a transmitting state and the light collecting unit 20 that heats the module housing 10 of the carbon dioxide capture system 1A according to the second embodiment of the present invention. Fig. 10 is a cross-sectional view in the axial direction of the module housing 10 in the sunlight adjustment unit 50A in a shielding state and the light collecting unit 20 that heats the module housing 10 of the carbon dioxide capture system 11A. In the following, the same reference numerals are used for the same configuration as in the first embodiment, and the description is omitted, and the configuration different from that of the first embodiment will be described. The carbon dioxide capture system 1A is different in that the state of the sunlight adjustment unit 50A is changed between a shielding state and a transmitting state by changing the posture of a plurality of plate-like members 52A.

[0078] As shown in FIG. 9, the carbon dioxide recovery system 1A has a module housing 10, a light collecting unit 20, a recovery unit 30, a temperature detection unit 40, a sunlight adjustment unit 50A, and a control unit 60 (see FIGS. 1 and 3).

[0079] The sunlight adjustment section 50A adjusts the amount of sunlight irradiated onto the module housing 10. The sunlight adjustment section 50A includes a plurality of plate-shaped members 52A and a plurality of rotation shafts 53A.

[0080] The plate-like members 52A are rectangular plate materials. The plate-like members 52A are positioned so as to cover the incident surface 21a of the concave mirror 21 on which the sunlight is incident. The incident surface 21a means a plane including two sides extending in the axial direction of the concave mirror 21. The plate-like members 52A are arranged so that their long sides extend in the axial direction of the concave mirror 21. The plate-like members 52A are arranged side by side in a direction perpendicular to the axial direction of the concave mirror 21 and parallel to the incident surface 21a at a position opposite to the incident surface 21a. The plate-like members 52A are also arranged so that their long sides are adjacent to each other.

[0081] The multiple rotation shafts 53A each support a plate-like member 52A. The multiple rotation shafts 53A are arranged to extend along the axial direction of the concave mirror 21. The multiple rotation shafts 53A are also arranged side by side in a direction perpendicular to the axial direction of the concave mirror 21 and parallel to the incident surface 21a. The multiple rotation shafts 53A are supported by a frame of the light collecting unit 20 (not shown) so as to be rotatable about their axes as rotation centers. The multiple rotation shafts 53A are configured to be rotatable at any rotation angle by a driving device (not shown).

[0082] The plate-like members 52A are each supported by a rotation shaft 53A that is positioned along the long side. Thus, the plate-like members 52A are configured to be rotatable about the rotation shaft 53A on the incident surface 21a. The plate-like members 52A are also configured to be changeable to any posture by a driving device (not shown).

[0083] The projected area of ​​the multiple plate-shaped members 52A on the incident surface 21a when viewed from a direction perpendicular to the incident surface 21a is minimized in a position where the end faces of the long sides of the plate-shaped members 52A, which are parallel to the thickness direction, face the incident surface 21a (a position substantially perpendicular to the incident surface 21a). In other words, the multiple plate-shaped members 52A can be changed to a transmission state that maximizes the gaps G between the plate-shaped members 52A through which sunlight can pass. In a position where the end faces of the multiple plate-shaped members 52A face the incident surface 21a, the projected area of ​​the multiple plate-shaped members 52A is the total area of ​​the areas of the end faces of the multiple plate-shaped members 52A. Therefore, the multiple plate-shaped members 52A block sunlight by the ratio of the total area of ​​the areas of the end faces to the area of ​​the incident surface 21a.

[0084] As shown in FIG. 10, the projected area of ​​the plurality of plate-shaped members 52A on the incident surface 21a when viewed from a direction perpendicular to the incident surface 21a is maximum when the principal surface, which is the surface of the plate-shaped members 52A with the largest area, faces the incident surface 21a (attitude substantially parallel to the incident surface 21a). In other words, the plurality of plate-shaped members 52A can be changed to a shielding state that minimizes the gap G between the plate-shaped members 52A through which sunlight can pass. When the long sides of adjacent plate-shaped members 52A overlap each other in an attitude in which the principal surfaces of the plurality of plate-shaped members 52A face the incident surface 21a, the projected area of ​​the plurality of plate-shaped members 52A is equal to the incident surface 21a. Thus, the plurality of plate-shaped members 52A shields sunlight.

[0085] 9 and 10, the gap G between adjacent plate-shaped members 52A changes with a change in posture caused by rotation of the rotation shaft 53A. Thus, the sunlight adjustment unit 50A having the plurality of plate-shaped members 52A is configured to be able to change the adjustment state between a blocking state in which the main surfaces of the plurality of plate-shaped members 52A face the incident surface 21a to a transmitting state in which the end surfaces of the plurality of plate-shaped members 52A face the incident surface 21a.

[0086] The control unit 60 is electrically connected to the exhaust pump 32, a drive device of the light collecting unit 20, and a drive device (not shown) of the sunlight adjustment unit 50A. The control unit 60 can transmit a posture signal to the drive device (not shown) of the sunlight adjustment unit 50A for changing the posture of the multiple plate-like members 52A between the transmitting state and the blocking state based on the temperature of the module housing 10 detected by the thermometer 41.

[0087] When the temperature T1 inside the housing unit 11 detected by the thermometer 41 is higher than the upper limit temperature TH, the control unit 60 changes the posture of the multiple plate-like members 52A to approach the posture of the shielded state (see FIG. 10). This reduces the amount of sunlight irradiated onto the module housing 10, and the temperature T1 drops. The control unit 60 may control the posture of the multiple plate-like members 52A according to a correlation between the posture of the multiple plate-like members 52A and the temperature rise of the module housing 10, which has been acquired in advance.

[0088] The carbon dioxide capture system 1A can adjust the amount of sunlight irradiated onto at least one of the light collector 20 and the module housing 10 by changing the posture of the multiple plate-like members 52A. Therefore, the amount of sunlight irradiated onto the module housing 10 is maintained within a certain range even if the amount of sunlight irradiated varies. This makes it possible to uniformly heat the absorbent 102a (see FIG. 7) of the carbon dioxide capture module 101 housed in the module housing 10 and to maintain the temperature of the absorbent 102a within a predetermined temperature range.

[0089] [Modification 1 of the second embodiment] Next, a carbon dioxide capture system 1B which is a modified example of the carbon dioxide capture system according to the second embodiment of the present invention will be described with reference to Fig. 11. Fig. 11 is a cross-sectional view in the axial direction of the module housing 10 at a plurality of light collecting sections 20 and a sunlight adjustment section 50B in a transmissive state which heat the plurality of module housings 10 of the carbon dioxide capture system 1B according to a first modified example of the second embodiment of the present invention. The carbon dioxide capture system 1B differs in that it heats a plurality of module housings 10.

[0090] As shown in FIG. 11, the carbon dioxide recovery system 1B has three module housings 10, three light collecting units 20, a recovery unit 30, three temperature detection units 40, a sunlight adjustment unit 50B, and a control unit 60 (see FIGS. 1 and 3).

[0091] 11, the sunlight adjustment unit 50B adjusts the amount of sunlight irradiated onto the three module housings 10. The sunlight adjustment unit 50B includes a plurality of plate-shaped members 52B, a plurality of rotating shafts 53B, and a housing 54B.

[0092] The plate members 52B are rectangular plates. The plate members 52B are positioned to cover an incident surface 54Ba, which is an opening in the housing 54B through which sunlight enters. The plate members 52B are arranged in a line in a direction perpendicular to the axial direction of the concave mirror 21 and parallel to the incident surface 54Ba at positions facing the incident surface 54Ba.

[0093] The multiple rotation shafts 53A each support a plate-like member 52A. The multiple rotation shafts 53A are arranged side by side in a direction perpendicular to the axial direction of the concave mirror 21 and parallel to the housing 54B. The multiple rotation shafts 53A are supported by the housing 54B so as to be rotatable about their axes by a driving device (not shown).

[0094] The housing 54B houses three module housings 10 and three light collecting units 20. The housing 54B is configured so that sunlight enters the inside from an entrance surface 54Ba which is an opening. The entrance surface 54Ba of the housing 54B which is an opening through which sunlight enters is covered by a plurality of plate-like members 52B.

[0095] The carbon dioxide capture system 1B configured in this manner is configured to be able to change the adjustment state of the sunlight adjustment unit 50B between a blocking state in which the multiple plate-shaped members 52B block sunlight and a transmitting state in which the multiple plate-shaped members 52B transmit sunlight. Thus, the carbon dioxide capture system 1B can change the amount of sunlight irradiated onto the three concave mirrors 21 in the housing 54B. This makes it possible to uniformly heat the absorbents 102a (see FIG. 7) contained in the multiple carbon dioxide capture modules 101 respectively housed in the multiple module housings 10, and to maintain the temperature of the absorbents 102a contained in the multiple carbon dioxide capture modules 101 within a predetermined temperature range.

[0096] [Modification 2 of the second embodiment] Next, a carbon dioxide capture system 1C which is a modified example of the carbon dioxide capture system according to the second embodiment of the present invention will be described with reference to Fig. 12 and Fig. 13. Fig. 12 is a cross-sectional view in the axial direction of the module housing 10 in the light collecting unit 20 which heats the module housing 10 of the carbon dioxide capture system 1C according to the second modified example of the second embodiment of the present invention, and the sunlight adjustment unit 50C in the transmitting state. Fig. 13 is a cross-sectional view in the axial direction of the module housing 10 in the light collecting unit 20 which heats the module housing 10 of the carbon dioxide capture system 1C, and the sunlight adjustment unit 50C in the shielding state.

[0097] As shown in FIG. 12, the carbon dioxide recovery system 1C has a module housing 10, a light collecting unit 20, a recovery unit 30, a temperature detection unit 40, a sunlight adjustment unit 50C, and a control unit 60 (see FIGS. 1 and 3).

[0098] The sunlight adjustment section 50C adjusts the amount of sunlight irradiated onto the module housing 10. The sunlight adjustment section 50C includes a shielding member 55C.

[0099] The shielding member 55C is a cylindrical member. The shielding member 55C has a transmitting portion 55Ca that transmits sunlight and a shielding portion 55Cb that shields sunlight. The transmitting portion 55Ca is an opening formed on the circumferential surface of the shielding member 55C. The module housing 10 and the concave mirror 21 are disposed inside the shielding member 55C. Thus, the shielding member 55C covers the module housing 10 and the concave mirror 21. The axis of the shielding member 55C coincides with the axis of the concave mirror 21. The shielding member 55C is configured to be rotatable around the axis as a rotation center by a driving device (not shown). That is, the shielding member 55C is configured to be rotatable around the axis as a rotation center in the circumferential direction with respect to the module housing 10 and the concave mirror 21.

[0100] The shading member 55C transmits sunlight through the transmitting portion 55Ca when the transmitting portion 55Ca is in an orientation where it faces the incident surface 21a of the concave mirror 21. That is, the shading member 55C is changeable to a transmitting state, which is an orientation where the shading member 55C transmits sunlight.

[0101] 13, the shielding member 55C shields sunlight when the shielding portion 55Cb faces the incident surface 21a. That is, the shielding member 55C is changeable to a transmitting state, which is a position for shielding sunlight.

[0102] 12 and 13, the portion of the shading member 55C facing the incident surface 21a is switched with a change in posture due to rotation about the axis as the center of rotation. Thus, the sunlight adjustment unit 50A having the shading member 55C is configured to be able to change the adjustment state between a shielding state posture in which the shading portion 55Cb of the shading member 55C faces the incident surface 21a and a transmitting state posture in which the transmitting portion 55Ca of the shading member 55C faces the incident surface 21a.

[0103] The control unit 60 is electrically connected to the exhaust pump 32, a drive device of the light collecting unit 20, and a drive device (not shown) of the sunlight adjustment unit 50C. The control unit 60 can transmit a posture signal to the drive device (not shown) of the sunlight adjustment unit 50C to change the posture of the shielding member 55C to the transmitting state or the shielding state based on the temperature of the module housing 10 detected by the thermometer 41.

[0104] When the temperature T1 inside the housing unit 11 detected by the thermometer 41 is higher than the upper limit temperature TH, the control unit 60 changes the posture of the shielding member 55C to the posture of the shielding state (see FIG. 13). This blocks the sunlight concentrated on the module housing 10 by the concave mirror 21, and the temperature T1 drops.

[0105] The sunlight adjustment unit 50C of the carbon dioxide capture system 1C is configured to be switchable between a transmitting state in which sunlight is permitted to be irradiated onto the light collecting unit 20 and the module housing 10 and a blocking state in which sunlight irradiated onto the light collecting unit 20 and the module housing 10 is blocked by rotating the blocking member 55C about an axis relative to the light collecting unit 20 or the module housing 10 as the center of rotation. Thus, the amount of sunlight irradiated onto the module housing 10 is maintained within a certain range even if irradiation conditions such as date, time, and weather change. The absorbent 102a (see FIG. 7) of the carbon dioxide capture module 101 housed in the module housing 10 can be uniformly heated and the temperature of the absorbent 102a can be maintained within a predetermined temperature range.

[0106] [Embodiment 3] Next, a carbon dioxide capture system 1D which is a third embodiment of the carbon dioxide capture system of the present invention will be described with reference to Fig. 14. Fig. 14 is a cross-sectional view in the axial direction of the module housing 10 at a light collecting unit 20 which heats the module housing 10, an exterior body 70 which houses the module housing, and a sunlight adjustment unit 50A of the carbon dioxide capture system 1D according to the third embodiment of the present invention. The carbon dioxide capture system 1D differs in that it has an exterior body 70 and water 80 which is a heat medium.

[0107] As shown in FIG. 14, the carbon dioxide recovery system 1D has a module housing 10, a light collecting unit 20, a recovery unit 30, a temperature detection unit 40, a sunlight adjustment unit 50A, a control unit 60, an exterior body 70, and water 80 (see FIGS. 1 and 3).

[0108] The exterior body 70 is a container that contains the module housing 10 and water 80, which is a heat medium. The exterior body 70 has a housing section 71 that can house the entire module housing 10. The housing section 71 is configured to be able to be sealed. The exterior body 70 has an outer surface 72 and an inner surface 73 that constitutes the housing section 71. A heat insulating chamber 74 in a vacuum state is formed between the outer surface 72 and the inner surface 73. In other words, the exterior body 70 insulates the inside of the housing section 71 from the outside. In addition, the exterior body 70 can store water 80, which is a heat medium, in the housing section 71. The exterior body 70 is configured, for example, in a cylindrical shape. The exterior body 70 is made of glass or the like that can transmit sunlight.

[0109] The water 80 functions as a heat medium. The water 80 is located between the exterior body 70 and the module housing 10 housed in the exterior body 70. That is, the water 80 covers the outer surface of the module housing 10. In the water 80, thermal conduction and convection occur due to the heat of sunlight between the exterior body 70 and the module housing 10 housed in the exterior body 70. Therefore, the temperature of the water 80 becomes uniform as a whole due to thermal conduction and convection. As a result, the water 80 can transmit heat to parts of the module housing 10 that are not irradiated with sunlight.

[0110] The light collecting unit 20 collects sunlight to heat the water 80 located in the storage unit 71 of the exterior body 70. The concave mirror 21 is located so as to surround the exterior body 70. The light collecting unit 20 is configured to collect sunlight on the exterior body 70 by the concave mirror 21.

[0111] The temperature detection unit 40 detects the temperature of the water 80. The temperature detection unit 40 includes a thermometer 41 (see FIGS. 1 and 3). The thermometer 41 is located inside the storage unit 71. The thermometer 41 is located, for example, at the top of the storage unit 71. Thus, the thermometer 41 is configured to detect the temperature of the water 80 inside the storage unit 71.

[0112] The sunlight adjustment unit 50 adjusts the amount of sunlight irradiated onto the module housing 10. The sunlight adjustment unit 50 includes a light control member 51. The light control member 51 is positioned so as to cover the reflective surface of the concave mirror 21 facing the module housing 10.

[0113] The carbon dioxide capture system 1D having the above-mentioned configuration is heated by the energy of sunlight via the water 80. The heat of the part of the water 80 that has been heated by irradiation with sunlight is transferred to the entire water 80 by thermal conduction and convection. The module housing 10 is uniformly heated by the water 80 whose temperature has been raised almost uniformly throughout. Furthermore, the carbon dioxide capture system 1D changes the adjustment state of the sunlight adjustment unit 50 based on the temperature of the water 80 in the exterior body 70. Thus, the water 80 in the exterior body 70 is maintained within a predetermined temperature range. This makes it possible to uniformly heat the absorbent 102a of the carbon dioxide capture module 101 and maintain the temperature of the absorbent 102a within a predetermined temperature range.

[0114] [Other embodiments] In the first embodiment, the temperature detection unit 40 is located in an upper portion within the housing portion 11 of the module housing 10. However, the temperature detection unit may be disposed in a middle portion or a lower portion of the housing portion of the module housing.

[0115] In the first embodiment, the temperature detection unit 40 is located inside the housing unit 11. However, the temperature detection unit may be disposed in the module housing main body.

[0116] In the first embodiment, the housing section 11 has one temperature detection section 40. However, the housing section of the module housing may have two or more temperature detection sections.

[0117] In the first embodiment, the sunlight adjustment unit 50 adjusts the amount of sunlight irradiated onto the concave mirror 21 based on the temperature T1 inside the accommodation unit 11 detected by one temperature detection unit 40. However, the sunlight adjustment unit may control the amount of sunlight irradiation based on the temperatures inside the accommodation unit of the module accommodation body detected by multiple temperature detection units.

[0118] In the first embodiment, the light control member 51 covers the reflective surface of the concave mirror 21. However, the light control member may be configured to cover the outer peripheral surface of the module housing. The light control member may be located in any position as long as it can block the sunlight concentrated by the concave mirror.

[0119] In the first embodiment, the sunlight adjustment unit 50 adjusts the amount of sunlight irradiation by the light control member 51 located on the reflective surface of the concave mirror 21. However, the sunlight adjustment unit may adjust the amount of sunlight irradiation by changing the position of the concave mirror.

[0120] In the second embodiment, in the sunlight adjustment unit 50A of the carbon dioxide capture system 1A, the multiple plate-shaped members 52A are arranged to extend in the axial direction of the concave mirror 21 and in a direction parallel to the incident surface 21a. However, the multiple plate-shaped members may be arranged to extend in a direction perpendicular to the axis of the concave mirror and parallel to the incident surface of the concave mirror.

[0121] In the second embodiment, the sunlight adjustment unit 50A of the carbon dioxide capture system 1A changes the position of the multiple plate-shaped members 52A to switch between the blocking state and the transmitting state. However, the sunlight adjustment unit may change the position of one or more plate-shaped members to switch between the blocking state and the transmitting state.

[0122] In the first modification of the second embodiment, three module housings 10 and three concave mirrors 21 are arranged in the housing 54B of the carbon dioxide capture system 1B. However, it is sufficient that a plurality of module housings and a plurality of concave mirrors are arranged in the housing.

[0123] In the second modification of the second embodiment, the carbon dioxide capture system 1C blocks sunlight with a shading member 55C that can rotate in a circumferential direction around the axis of the concave mirror 21 as the center of rotation with respect to the module housing 10 and the concave mirror 21. However, the carbon dioxide capture system may be configured to block sunlight with a shading member that can move in the axial direction of the concave mirror or in a direction perpendicular to the axial direction of the concave mirror with respect to the module housing and the concave mirror. The carbon dioxide capture system may also be configured to block sunlight with a plate-shaped shading member that can move parallel to the incident surface of the concave mirror.

[0124] In the first embodiment, the carbon dioxide capture system 1 uses water 80 as the heat medium. However, the heat medium may be a liquid mainly composed of mineral oil or chemically synthetic oil. The heat medium may be a liquid mainly composed of water mixed with a substance that lowers the freezing point of water, a liquid mainly composed of water mixed with a substance that raises the boiling point of water, or a liquid mainly composed of ethylene glycol or propylene glycol.

[0125] Although the embodiment of the present invention has been described above, the above-mentioned embodiment is merely an example for carrying out the present invention. Therefore, the present invention is not limited to the above-mentioned embodiment, and it is possible to carry out the above-mentioned embodiment by appropriately modifying it within the scope of the gist of the present invention. [Explanation of symbols]

[0126] 1, 1A, 1B, 1C, 1D Carbon dioxide capture system 10 Module housing 20 Light collecting section 21 concave mirror 21a, 54Ba entrance plane 11, 71 Storage unit 30 Collection Department 31 Carbon dioxide capture tank 32 Exhaust pump 33 Exhaust pipe 34 Carbon dioxide concentration meter 40 Temperature detection section 41 Thermometer 50, 50A, 50B, 50C solar adjustment section 51 Light control components 52A, 52B Plate-shaped members 53A, 53B Rotating shaft 54B case 55C Shielding materials 55Ca transparent part 55Cb Shielding part 60 Control section 70 Exterior body 72 External surface 73 Inner surface 74 Insulated Room 80 water 101 Carbon dioxide capture module 102 Absorption section 102a Absorbing material 103 Filter section 104 Sealing part T1 Module housing temperature TH upper limit temperature C0 reference concentration C1 Carbon dioxide concentration G Gap

Claims

1. A carbon dioxide capture system that heats an absorbent that has absorbed carbon dioxide to desorb and capture the carbon dioxide from the absorbent, a module housing that houses a carbon dioxide capture module including the absorbent; A light collecting unit that collects sunlight and heats the module housing; A recovery section that recovers carbon dioxide desorbed from the absorbent; a sunlight adjustment unit that can be changed between a blocking state for blocking sunlight irradiated to at least one of the light collecting unit and the module housing and a transmitting state for transmitting the sunlight, Carbon dioxide capture system.

2. 2. The carbon dioxide capture system according to claim 1, a temperature detection unit for detecting a temperature of the module housing; A control unit that controls the adjustment state of the sunlight adjustment unit, The control unit is changing an adjustment state of the sunlight adjustment unit between the blocking state and the transmitting state based on the temperature of the module housing detected by the temperature detection unit; Carbon dioxide capture system.

3. The carbon dioxide recovery system according to claim 1 or 2, an exterior body that houses the module housing; a heat medium located between the module housing and the exterior body and covering the module housing, The temperature detection unit is Detecting the temperature of the module housing via the heat medium; The control unit is changing an adjustment state of the sunlight adjustment unit between the blocking state and the transmitting state based on the temperature of the module housing detected by the temperature detection unit; Carbon dioxide capture system.

4. The carbon dioxide recovery system according to claim 1 or 2, The sunlight adjustment unit is a light control member that is positioned so as to cover the reflective surface of the light collecting unit or the module housing, and that is changeable between the blocking state and the transmitting state by applying a voltage; Carbon dioxide capture system.

5. The carbon dioxide recovery system according to claim 1 or 2, The sunlight adjustment unit is a plurality of plate-shaped members positioned to cover the light collecting unit and the module housing; Each of the plate-like members is The plate-shaped member is configured to be rotatable about an axis extending in a direction perpendicular to the thickness direction of the plate-shaped member, and the adjustment state of the sunlight adjustment unit can be changed between the blocking state and the transmitting state by rotating the plurality of plate-shaped members. Carbon dioxide capture system.

6. The carbon dioxide recovery system according to claim 1 or 2, The sunlight adjustment unit is a shielding member positioned to cover the light collecting unit and the module housing; The shielding member is The light collector is configured to be movable relative to the light collecting unit or the module housing, and the adjustment state of the sunlight adjustment unit can be changed between the blocking state and the transmitting state by moving the blocking member. Carbon dioxide capture system.

7. The carbon dioxide recovery system according to claim 1 or 2, a plurality of the light collecting units and a plurality of the module housings; The sunlight adjustment unit is a plurality of plate-shaped members positioned to cover the plurality of light collecting portions and the plurality of module housings; Each of the plate-like members is The plate-shaped member is configured to be rotatable about an axis extending in a direction perpendicular to the thickness direction of the plate-shaped member, and the adjustment state of the sunlight adjustment unit can be changed between the blocking state and the transmitting state by rotating the plurality of plate-shaped members. Carbon dioxide capture system.

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