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 range.SOLUTION: A carbon dioxide recovery system includes: a module accommodation body 10 that accommodates a carbon dioxide collection module 101; an exterior body 20 that accommodates the module accommodation body 10; water 35 that covers the module accommodation body 10; a heating medium supply section 30 that supplies the water 35 to an accommodation section 21 of the exterior body 20; a heating section 40 that heats the water 35 by using sunlight; a recovery section 50 that recovers carbon dioxide desorbed from an absorber 102a; a temperature detection section 60 that detects a temperature of the water 35 located in the accommodation section 21 by the heating medium supply section 30; and a control section 90 that controls the heating medium supply section 30. The control section 90 supplies new water 35 to the accommodation section 21 by using the heating medium supply section 30 on the basis of the temperature of the water 35 in the accommodation section 21 detected by the temperature detection section 60, and controls temperature T1 of the water 35 in the accommodation section 21.SELECTED DRAWING: Figure 1

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 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 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 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 within a predetermined range. 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 desorbs and captures carbon dioxide from the absorbent. The carbon dioxide capture system includes a module housing that houses a carbon dioxide capture module including the absorbent, an exterior body that houses the module housing, a heat medium that covers the module housing, a heat medium supplying unit that supplies the heat medium between the module housing housed in the exterior body and the exterior body, a heating unit that heats the heat medium located between the module housing and the exterior body by sunlight, a recovery unit that recovers carbon dioxide desorbed from the absorbent, a temperature detection unit that detects the temperature of the heat medium located between the module housing housed in the exterior body and the exterior body by the heat medium supplying unit, and a control unit that controls the heat medium supplying unit. The control unit supplies new heat medium between the module housing housed in the exterior body and the exterior body by the heat medium supplying unit based on the temperature of the heat medium in the exterior body detected by the temperature detection unit, and controls the temperature of the heat medium located between the module housing housed in the exterior body and the exterior body.

[0010] The carbon dioxide capture system having the above-mentioned configuration covers the module housing located in the exterior body with a heat medium. The module housing is heated through the heat medium by the energy of sunlight. The heat medium transfers heat from a portion that has been 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 been increased almost uniformly throughout. In addition, the carbon dioxide capture system supplies new heat medium by a heat medium supply unit to adjust the temperature of the heat medium 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 uniformly heat the absorbent and maintain the temperature of the absorbent within a predetermined range.

[0011] From another viewpoint, it is preferable that the carbon dioxide capture system of the present invention includes the following configuration: The heat medium supply unit has an adjustment unit that adjusts a flow rate of the heat medium supplied between the module housing housed in the exterior body and the exterior body.

[0012] In the carbon dioxide capture system having the above-mentioned configuration, the supply amount of the heat medium can be easily adjusted by the adjustment unit. Therefore, the heat medium between the module housing housed in the exterior body and the exterior body is easily maintained within a predetermined temperature range by supplying new heat medium. This makes it possible to uniformly heat the absorbent and maintain the temperature of the absorbent within a predetermined 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 a plurality of the module housings and a plurality of the exterior bodies that house the plurality of module housings, respectively. The plurality of exterior bodies are connected in parallel to the heat medium supply unit. The heat medium supply unit is configured to be able to supply the heat medium between the exterior body and the module housings housed in the plurality of exterior bodies, respectively.

[0014] The carbon dioxide capture system having the above-mentioned configuration has a plurality of exterior bodies connected in parallel to the heat medium supply unit and a plurality of module housings respectively housed in the plurality of exterior bodies. Thus, the carbon dioxide capture system can capture carbon dioxide from the absorbents of a plurality of carbon dioxide capture modules. Furthermore, the carbon dioxide capture system can individually control the temperature of the heat medium in each of the exterior bodies by individually supplying the heat medium into each of the exterior bodies by the heat medium supply unit. This makes it possible to uniformly heat the plurality of absorbents and maintain the temperature of the plurality of absorbents within a predetermined range.

[0015] From another viewpoint, it is preferable that the carbon dioxide capture system of the present invention includes the following configuration: The heat medium supply unit includes a storage tank that stores the heat medium, and a pump that supplies the heat medium from the storage tank between the module housing housed in the exterior body and the exterior body. The heat medium supply unit supplies the heat medium from the storage tank between the module housing and the exterior body by the pump.

[0016] The carbon dioxide capture system having the above-mentioned configuration can supply the heat medium stored in the storage tank to the exterior body by the pump. Therefore, since the carbon dioxide capture system stores a lump amount of the heat medium in the storage tank, it can respond to supply of the heat medium at various times and in various amounts. This makes it possible to uniformly heat the absorbent and maintain the temperature of the absorbent within a predetermined range.

[0017] 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 circulation unit that returns the heat medium in the exterior body to the storage tank. When a volume of the heat medium in the exterior body exceeds a reference value, the circulation unit returns the heat medium that exceeds the reference value to the storage tank.

[0018] The carbon dioxide capture system having the above-mentioned configuration supplies new heat medium into the exterior body to adjust the temperature of the heat medium inside the exterior body, and when the amount of the heat medium inside the exterior body exceeds a reference value, the circulation unit returns the amount of the heat medium that exceeds the reference value to the storage tank. In other words, the carbon dioxide capture system has a path for circulating the heat medium between the exterior body and the storage tank. This makes it possible to uniformly heat the absorbent material and maintain the temperature of the absorbent material within a predetermined range without causing the heat medium to overflow from the exterior body.

[0019] According to another aspect, the carbon dioxide recovery system of the present invention preferably includes the following configuration: The heat medium is oil, water, a mixture of water and a substance that lowers the freezing point of water, or an antifreeze.

[0020] The carbon dioxide capture system having the above-mentioned configuration heats the heat medium, which is oil, water, or a mixture of water and a substance that lowers the freezing point of water, with sunlight. When the heat medium is heated, convection occurs between the exterior body and the module housing. Thus, the temperature of the heat medium is made uniform by the convection. This makes it possible to heat the absorbent uniformly and maintain the temperature of the absorbent within a predetermined range. Effect of the Invention

[0021] 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]

[0022] [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 schematic diagram showing a heating state of the carbon dioxide capture module 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 perspective view showing a carbon dioxide capture module that desorbs carbon dioxide by the carbon dioxide capture system according to the first embodiment of the present invention. [Diagram 5] FIG. 5 is an axial cross-sectional view of a carbon dioxide capture module that desorbs carbon dioxide by the carbon dioxide capture system according to the first embodiment of the present invention. [Figure 6] FIG. 6 is a diagram showing a flowchart of carbon dioxide capture control in the carbon dioxide capture system according to the first embodiment of the present invention. [Figure 7]FIG. 7 is a schematic diagram of a carbon dioxide capture system according to a modified example of the first embodiment of the present invention. [Figure 8] FIG. 8 is a schematic diagram of a carbon dioxide capture system according to a second embodiment of the present invention. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0023] 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.

[0024] 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.

[0025] [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. 3. 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 schematic diagram 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.

[0026] 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.

[0027] As shown in FIG. 1, the carbon dioxide capture system 1 has a module housing 10, an exterior body 20, a heat medium supply unit 30, a heating unit 40, a capture unit 50, a temperature detection unit 60, a regulating valve 70, a circulation unit 80, and a control unit 90.

[0028] 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 airtight. The module housing 10 is configured, for example, in a cylindrical shape. The module housing 10 is made of a metal with good thermal conductivity, such as copper, brass, stainless steel, or aluminum.

[0029] The exterior body 20 is a container that contains the module housing 10 and water 35, which is a heat medium. The exterior body 20 has a housing section 21 that can house the entire module housing 10. The housing section 21 is configured to be able to be sealed. The exterior body 20 has an outer surface 22 and an inner surface 23 that constitutes the housing section 21. A heat insulating chamber 24 in a vacuum state is formed between the outer surface 22 and the inner surface 23. In other words, the exterior body 20 insulates the inside of the housing section 21 from the outside. The exterior body 20 can also store water 35, which is a heat medium, in the housing section 21. The exterior body 20 is configured, for example, in a cylindrical shape. The exterior body 20 is made of glass or the like that can transmit sunlight.

[0030] The heat medium supplying unit 30 supplies water 35, which is a heat medium, into the storage unit 21. The heat medium supplying unit 30 has a storage tank 31, a water pump 32, a water pipe 33, and a liquid level gauge .

[0031] The storage tank 31 stores the water 35. The storage tank 31 is placed indoors where it is not directly exposed to sunlight in order to suppress an increase in the temperature of the water 35.

[0032] The water supply pump 32 supplies water 35 stored in the storage tank 31 between the exterior body 20 and the module housing 10 housed in the exterior body 20. The water supply pump 32 is configured to be able to suck the water 35 from the storage tank 31 via the water supply pipe 33. The water supply pump 32 is also configured to be able to discharge the water 35 to the housing section 21 via the water supply pipe 33.

[0033] The liquid level gauge 34 detects the liquid level of the water 35 in the housing 21. That is, the liquid level gauge 34 detects the amount of water 35 sent by the water supply pump 32 between the exterior body 20 and the module housing 10 housed in the exterior body 20. The liquid level gauge 34 is located inside the exterior body 20. Note that the carbon dioxide capture system 1 only needs to have a means for calculating the amount of water 35 sent to the exterior body 20 by the water supply pump 32. The means for calculating the amount of the sent water 35 may be a water meter, a weight scale, or the like. The carbon dioxide capture system 1 may calculate the amount of water 35 sent to the exterior body 20 by the water supply pump 32 from the operation time of the water supply pump 32, for example.

[0034] The water 35 functions as a heat medium. The water 35 is located between the exterior body 20 and the module housing 10 housed in the exterior body 20. That is, the water 35 covers the outer surface of the module housing 10. Between the exterior body 20 and the module housing 10 housed in the exterior body 20, thermal conduction and convection occur in the water 35 due to the heat of sunlight. Therefore, the entire temperature of the water 35 becomes uniform due to thermal conduction and convection. As a result, the water 35 can transmit heat to parts of the module housing 10 that are not irradiated with sunlight.

[0035] 1 and 2, the heating unit 40 is configured as a light collecting device that collects sunlight and heats the water 35 located in the storage unit 21 of the exterior body 20. The heating unit 40 has a concave mirror 41. The concave mirror 41 is positioned so as to surround the exterior body 20. The heating unit 40 is configured to collect sunlight on the exterior body 20 by the concave mirror 41. In addition, the heating unit 40 is configured so that the position of the concave mirror 41 can be adjusted by a driving device (not shown) so as to collect sunlight from a moving sun on the exterior body 20.

[0036] 1, the capture unit 50 captures the carbon dioxide desorbed from the carbon dioxide capture module 101. The capture unit 50 has a carbon dioxide capture tank 51, an exhaust pump 52, an exhaust pipe 53, and a carbon dioxide concentration meter .

[0037] The carbon dioxide capture tank 51 stores carbon dioxide. The carbon dioxide capture tank 51 is configured to be able to seal the carbon dioxide.

[0038] The exhaust pump 52 exhausts carbon dioxide within the housing section 11 of the module housing 10 to the carbon dioxide capture tank 51. The exhaust pump 52 is configured to be able to suck in carbon dioxide from the module housing 10 via an exhaust pipe 53. The exhaust pump 52 is also configured to be able to discharge carbon dioxide to the carbon dioxide capture tank 51 via the exhaust pipe 53.

[0039] The carbon dioxide concentration meter 54 detects the concentration of carbon dioxide in the storage unit 11. The carbon dioxide concentration meter 54 is located in the storage unit 11. The carbon dioxide concentration meter 54 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.

[0040] The temperature detection unit 60 detects the temperature of the water 35 located between the exterior body 20 and the module housing 10 housed in the exterior body 20. The temperature detection unit 60 is a temperature sensor. The temperature detection unit 60 is located between the exterior body 20 and the module housing 10 housed in the exterior body 20. The temperature detection unit 60 is located, for example, at an upper part of the housing section 21. Thus, the temperature detection unit 60 is configured to detect the upper temperature of the water 35 between the exterior body 20 and the module housing 10 housed in the exterior body 20.

[0041] The regulating valve 70 is an adjusting unit that adjusts the amount of water 35 sent to the storage unit 21 by the water pump 32. The regulating valve 70 is, for example, a solenoid valve. The regulating valve 70 adjusts the amount of water supplied to the storage unit 21 by switching between an open state and a closed state. The regulating valve 70 is provided in the water supply pipe 33 that is connected to the outlet of the water supply pump 32.

[0042] The circulation unit 80 returns the water 35 located between the exterior body 20 and the module housing 10 housed in the exterior body 20 to the storage tank 31. The circulation unit 80 is a pipe. The inlet for taking in the water 35 in the circulation unit 80 is located at the top of the housing unit 21. The outlet for discharging the water 35 in the circulation unit 80 is located inside the storage tank 31. When the water 35 in the housing unit 21 reaches the inlet of the circulation unit 80, it flows from the circulation unit 80 into the storage tank 31. In other words, when the volume of the water 35 in the housing unit 21 exceeds the spatial volume between the exterior body 20 and the module housing 10 housed in the exterior body 20, which is a reference value, the circulation unit 80 returns the portion of the water 35 that exceeds the reference value to the storage tank 31. In this way, the circulation unit 80 circulates the water 35, which is a heat medium, between the exterior body 20 and the storage tank 31.

[0043] The carbon dioxide capture system 1 does not necessarily have to have the circulation unit 80. The carbon dioxide capture system 1 may be configured to discharge the water 35 to the outside when the volume of the water 35 in the storage unit 21 exceeds a reference value.

[0044] 1 and 3, the control unit 90 controls the water pump 32, the exhaust pump 52, the heating unit 40, and the regulating valve 70. The control unit 90 is actually a CPU, a ROM, a RAM, a HDD, etc., connected via a bus. Alternatively, the control unit 90 is composed of a one-chip LSI or the like. The control unit 90 stores various programs and data for controlling the operations of the water pump 32, the exhaust pump 52, the heating unit 40, the regulating valve 70, etc.

[0045] The control unit 90 is electrically connected to the water pump 32, the exhaust pump 52, the heating unit 40, and the regulating valve 70. The control unit 90 can send start signals and stop signals to the water pump 32 and the exhaust pump 52. The control unit 90 can send a position signal to a drive device (not shown) of the heating unit 40 to adjust the position of the concave mirror 41 based on the date and time. The control unit 90 can send a switching signal to the regulating valve 70 to switch between an open state and a closed state.

[0046] The control unit 90 is electrically connected to the liquid level gauge 34, the carbon dioxide concentration meter 54, and the temperature detection unit 60. The control unit 90 can obtain a signal related to the amount of water 35 between the exterior body 20 and the module housing 10 housed in the exterior body 20 from the liquid level gauge 34. The control unit 90 can obtain a signal related to the concentration of carbon dioxide in the housing unit 11 from the carbon dioxide concentration meter 54. The control unit 90 can obtain a signal related to the temperature of the water 35 from the temperature detection unit 60.

[0047] <Configuration of carbon dioxide capture module> Next, a schematic configuration of the carbon dioxide capture module 101 will be described with reference to Fig. 4 and Fig. 5. Fig. 4 is a perspective view showing the carbon dioxide capture module 101 that desorbs carbon dioxide by the carbon dioxide capture system 1. Fig. 5 is a cross-sectional view in the axial direction of the carbon dioxide capture module 101 that desorbs carbon dioxide by the carbon dioxide capture system 1.

[0048] 4, 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] 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. 6. Fig. 6 is a diagram showing a flowchart of carbon dioxide capture control of the carbon dioxide capture system 1. Note that in the module housing 10 of the carbon dioxide capture system 1, two carbon dioxide capture modules 101 are sealed in a state of being stacked in the axial direction. Also, the housing section 21 of the exterior body 20 is sealed.

[0065] 6, in step S110 of the carbon dioxide capture control, when the control unit 90 of the carbon dioxide capture system 1 acquires an ON signal from a start switch (not shown), it transmits a start signal to the water pump 32. The control unit 90 also transmits a switching signal to the regulating valve 70 to switch it to an open state. The control unit 90 transitions to step S120. As a result, the carbon dioxide capture system 1 starts supplying water 35 to the storage unit 21.

[0066] In step S120, the control unit 90 determines whether or not the amount of water 35 fed by the water feed pump 32 has reached a reference value, based on a signal acquired from the liquid level gauge 34. As a result, when it is determined that the amount of water 35 fed by the water feed pump 32 to the exterior body 20 has reached the reference value, the control unit 90 shifts the step to step S130. On the other hand, when it is determined that the amount of water 35 fed by the water feed pump 32 to the exterior body 20 has not reached the reference value, the control unit 90 shifts the step to step S120.

[0067] In step S130, the control unit 90 transmits a switching signal to switch the regulating valve 70 to the closed state. The control unit 90 shifts the step to step S140. As a result, the carbon dioxide capture system 1 stops the supply of the water 35 to the storage unit 21.

[0068] In step S140, the control unit 90 transmits a position signal to the heating unit 40 to adjust the position of the concave mirror 41. The control unit 90 shifts the step to step S150. As a result, the carbon dioxide capture system 1 starts heating the water 35 in the storage unit 21 with sunlight.

[0069] In step S150, the control unit 90 acquires information relating to the temperature T1 of the water 35 from the temperature detection unit 60. The control unit 90 transitions to step S160.

[0070] In step S160, the control unit 90 transmits a start signal to the exhaust pump 52. The control unit 90 shifts the step to step S170. As a result, the carbon dioxide capture system 1 starts capturing the carbon dioxide in the storage unit 11.

[0071] In step S170, the control unit 90 determines whether the temperature T1 of the water 35 is equal to or lower than the upper limit temperature TH, based on information related to the temperature T1 of the water 35 acquired from the temperature detection unit 60. As a result, if it is determined that the temperature T1 of the water 35 is equal to or lower than the upper limit temperature TH, the control unit 90 shifts the step to step S180. On the other hand, if it is determined that the temperature T1 of the water 35 is not equal to or lower than the upper limit temperature TH, the control unit 90 shifts the step to step S280.

[0072] In step S180, the control unit 90 determines whether or not the carbon dioxide concentration C1 in the module housing 10 acquired from the carbon dioxide concentration meter 54 has continued to be less than the reference concentration C0 for a predetermined time. As a result, when 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 90 shifts the step to step S190. On the other hand, when 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 90 shifts the step to step S170.

[0073] In step S190, the control unit 90 transmits a stop signal to the exhaust pump 52. The control unit 90 ends the carbon dioxide capture control.

[0074] In step S280, the control unit 90 transmits a switching signal to switch the regulating valve 70 to an open state. The control unit 90 shifts the step to step S290. As a result, the carbon dioxide capture system 1 starts circulating the water 35 to the storage unit 21 to adjust the temperature of the water 35.

[0075] In step S290, the control unit 90 determines whether the temperature T1 of the water 35 is equal to or lower than the upper limit temperature TH, based on information related to the temperature T1 of the water 35 acquired from the temperature detection unit 60. As a result, if it is determined that the temperature T1 of the water 35 is equal to or lower than the upper limit temperature TH, the control unit 90 shifts the step to step S300. On the other hand, if it is determined that the temperature T1 of the water 35 is not equal to or lower than the upper limit temperature TH, the control unit 90 shifts the step to step S290.

[0076] In step S300, the control unit 90 transmits a switching signal to switch the regulating valve 70 to the closed state. The control unit 90 shifts the step to step S170. As a result, the carbon dioxide capture system 1 stops circulating the water 35 to the storage unit 21 for adjusting the temperature of the water 35.

[0077] In the carbon dioxide capture system 1 configured in this manner, the module housing 10 in the housing section 21 is covered with water 35. The module housing 10 is heated by the energy of sunlight via the water 35. The water 35 transfers heat from the portion that has been heated by irradiation with sunlight to the entire body by thermal conduction and convection. The module housing 10 is heated uniformly by the water 35, the temperature of which has been raised almost uniformly throughout.

[0078] Furthermore, the carbon dioxide capture system 1 adjusts the amount of new water 35 sent from the storage tank 31 to the storage unit 21 by the water pump 32 based on the temperature of the water 35 in the storage unit 21. Thus, the temperature T1 of the water 35 in the storage unit 21 is maintained at or below the upper limit temperature TH by the sending of the new water 35. The module storage body 10 is heated to a temperature T1 that is below the upper limit temperature TH by the water 35 that is maintained at or below the upper limit temperature TH.

[0079] Furthermore, the carbon dioxide capture system 1 can easily adjust the supply amount of water 35 by opening and closing the adjustment valve 70. Therefore, the temperature T1 of the water 35 in the storage unit 21 is likely to be maintained at or below the upper limit temperature TH by the supply of new water 35.

[0080] Furthermore, the carbon dioxide capture system 1 can supply the water 35 stored in the storage tank 31 to the exterior body 20 by the water supply pump 32. Therefore, since the carbon dioxide capture system 1 stores a large amount of water 35 in the storage tank 31, it can respond to the supply of the water 35 to the storage unit 21 at various times and in various amounts.

[0081] Furthermore, when the amount of water 35 in the storage unit 21 exceeds a reference value, the carbon dioxide capture system 1 returns the water that exceeds the reference value to the storage tank 31 by the circulation unit 80. In other words, the carbon dioxide capture system 1 has a path for circulating the water 35 between the exterior body 20 and the storage tank 31. This allows the carbon dioxide capture system 1 to circulate the water 35 between the exterior body 20 and the storage tank 31 without causing the water 35 to overflow from the exterior body 20. This allows the absorbent 102a to be heated uniformly and the temperature of the absorbent 102a to be maintained within a predetermined range.

[0082] [Modification of the first embodiment] Next, a carbon dioxide capture system 1A which is a modified example of the first embodiment of the carbon dioxide capture system of the present invention will be described with reference to Fig. 7. Fig. 7 is a schematic diagram of the carbon dioxide capture system 1A according to a modified example of the first embodiment of the present invention. In the following, the same components as those in the first embodiment are given the same reference numerals, and their description will be omitted, and components different from those in the first embodiment will be described. The carbon dioxide capture system 1A differs in that it does not have an adjustment valve 70.

[0083] The carbon dioxide capture system 1A has a control unit 90A. When the temperature T1 of the water 35 acquired from the temperature detection unit 60 is higher than the upper limit temperature TH, the control unit 90A transmits a start signal to the water supply pump 32 to supply the water 35 in the storage tank 31 into the accommodation unit 21 for a predetermined time. The control unit 90A repeatedly transmits a start signal to the water supply pump 32 to supply the water 35 in the storage tank 31 into the accommodation unit 21 for a predetermined time until the temperature T1 of the water 35 acquired from the temperature detection unit 60 becomes lower than the upper limit temperature TH.

[0084] Instead of controlling the water supply of the water 35 by the regulating valve 70, the carbon dioxide capture system 1A controls the water supply of the water 35 by the water supply pump 32 as an adjustment unit. By configuring in this way, the carbon dioxide capture system 1A can adjust the temperature of the water 35 between the exterior body 20 and the module housing body 10 housed in the exterior body 20 without using the regulating valve 70. Therefore, the absorbent 102a can be uniformly heated and the temperature of the absorbent 102a can be maintained within a predetermined range. In addition, since the water supply of the water 35 is controlled by the water supply pump 32, power is supplied to the water supply pump 32 when water supply is required. This makes it possible to reduce power consumption compared to a configuration in which the water supply is controlled by a regulating valve or the like in a state in which power is constantly supplied to the water supply pump. Note that the carbon dioxide capture system 1A may be configured to, for example, use a plurality of water supply pipes with different diameters as an adjustment unit and switch the water supply pipe from among the plurality of water supply pipes with different diameters according to the amount of water 35 required without using the regulating valve 70.

[0085] [Embodiment 2] Next, a carbon dioxide capture system 1B which is a second embodiment of the carbon dioxide capture system of the present invention will be described with reference to Fig. 8. Fig. 8 is a schematic diagram of the carbon dioxide capture system 1B. The carbon dioxide capture system 1B differs from the carbon dioxide capture system 1B in that water 35 is fed from one heat medium supply unit 30B to two exterior bodies 20, carbon dioxide is captured from the two exterior bodies 20 by one capture unit 50B, and water 35 is returned from the two exterior bodies 20 by one circulation unit 80B.

[0086] As shown in FIG. 8, the carbon dioxide capture system 1B has two module housings 10, two exterior bodies 20, a heat medium supply unit 30B, two heating units 40, a capture unit 50B, two temperature detection units 60, two regulating valves 70, a circulation unit 80B, and two control units 90.

[0087] The two exterior bodies 20 house the module housing 10 in their respective housing sections 21. A heating section 40 is located around each of the two exterior bodies 20. A temperature detection section 60 is located in each of the two exterior bodies 20 between the exterior body 20 and the module housing 10 housed in the exterior body 20.

[0088] The heat medium supplying unit 30B supplies water 35 into the two storage units 21. The heat medium supplying unit 30B has a storage tank 31, a water pump 32, a water supply pipe 33B, and two liquid level gauges .

[0089] The water supply pump 32 supplies water 35 stored in the storage tank 31 between the exterior bodies 20 and the module housing bodies 10 housed in the exterior bodies 20 in the two exterior bodies 20. The water supply pump 32 is configured to be able to suck the water 35 from the storage tank 31 via the water supply pipe 33B. The water supply pump 32 is also configured to be able to discharge the water 35 to each of the two exterior bodies 20 via the water supply pipe 33B. In this way, the water supply pipe 33B connects the two exterior bodies 20 in parallel to the water supply pump 32.

[0090] The two liquid level gauges 34 are located inside the storage section 21. The two liquid level gauges 34 detect the liquid levels of the water 35 inside the storage section 21, respectively.

[0091] The capture unit 50B captures the carbon dioxide desorbed from the carbon dioxide capture module 101. The capture unit 50B has a carbon dioxide capture tank 51, an exhaust pump 52, an exhaust pipe 53B, and two carbon dioxide concentration meters .

[0092] The exhaust pump 52 is configured to be able to suck in carbon dioxide from the two module housings 10 via the exhaust pipe 53B. The exhaust pump 52 is also configured to be able to discharge the carbon dioxide to the carbon dioxide capture tank 51 via the exhaust pipe 53B. In this manner, the exhaust pipe 53B connects the two module housings 10 to the exhaust pump 52.

[0093] The two regulating valves 70 respectively regulate the amount of water 35 fed to the two exterior bodies 20 by the water feed pump 32. The two regulating valves 70 are respectively provided in the portions of the water feed pipe 33B connected to the outlet of the water feed pump 32, which are connected to the two exterior bodies 20. Thus, when both regulating valves 70 are open, the water 35 is fed to both exterior bodies 20. When one regulating valve 70 is open, the water 35 is fed to one exterior body 20, but is not fed to the other exterior body 20. When both regulating valves 70 are closed, the water 35 is not fed to both exterior bodies 20.

[0094] The circulation unit 80B returns the water 35 located in each of the two exterior bodies 20 between the exterior bodies 20 and the module housing bodies 10 housed in the exterior bodies 20 to the storage tank 31. In the circulation unit 80B, an inlet for taking in the water 35 is located in the upper part of each of the two exterior bodies 20. In the circulation unit 80B, an outlet for discharging the water 35 is located inside the storage tank 31. The circulation unit 80B returns the water 35 in each of the two housing units 21 whose volume of the water 35 has exceeded a reference value to the storage tank 31.

[0095] The two control units 90 are electrically connected to the water pump 32 and the exhaust pump 52, respectively (not shown). Furthermore, the two control units 90 are each electrically connected to one heating unit 40. Furthermore, the two control units 90 are each electrically connected to one regulating valve 70. The two control units 90 are each electrically connected to one liquid level meter 34, one carbon dioxide concentration meter 54, and one temperature detection unit 60.

[0096] The two exterior bodies 20 of the carbon dioxide capture system 1B configured in this manner are connected in parallel to a heat medium supply unit 30B. The heat medium supply unit 30B can independently supply water 35 between the module housings 10 and the exterior bodies 20 housed in the two exterior bodies, respectively.

[0097] Therefore, the carbon dioxide capture system 1B can capture carbon dioxide from the absorbent 102a of the carbon dioxide capture module 101 by the two module housings 10. In addition, the carbon dioxide capture system 1B can individually control the temperature of the water 35 in each housing 21 by individually supplying the water 35 into each housing 21 by the heat medium supply unit 30B. This makes it possible to uniformly heat the two absorbents 102a and maintain the temperature of the two absorbents 102a within a predetermined range. Note that the carbon dioxide capture system 1B may be configured to adjust the amount of water 35 fed to each housing 21 by switching the water feed pipe from among the multiple water feed pipes with different diameters as an adjustment unit according to the amount of water 35 required without using the adjustment valve 70.

[0098] [Other embodiments] In the first embodiment, the temperature detection unit 60 is located in the upper part of the storage unit 21. However, the temperature detection unit may be disposed in the middle or lower part of the storage unit.

[0099] In the first embodiment, the temperature detection unit 60 is located in the upper part of the housing unit 21. However, the temperature detection unit may be disposed inside the housing unit of the module housing.

[0100] In the first embodiment, the storage unit 21 has one temperature detection unit 60. However, the storage unit 21 may have two or more temperature detection units.

[0101] In the first embodiment, the heat medium supplying unit 30 supplies new water 35 to the accommodation unit 21 based on the temperature T1 of the water 35 detected by the temperature detecting unit 60. However, the heat medium supplying unit may control the water supply based on the water temperatures detected by a plurality of temperature detecting units. The plurality of temperature detecting units may be disposed, for example, in the accommodation unit of the exterior body and in the accommodation unit of the module accommodation unit.

[0102] In the first embodiment, the regulating valve 70 is configured by a solenoid valve. However, the regulating valve may be configured by a valve capable of changing the flow rate, such as an electromagnetic proportional control valve. This allows the carbon dioxide capture system to change the amount of water sent into the storage section of the exterior body depending on the water temperature.

[0103] In the first embodiment, the carbon dioxide capture system 1 uses the regulating valve 70 as an adjusting unit to adjust the amount of water 35 supplied to the storage unit 21. However, the carbon dioxide capture system may be configured to, for example, use a plurality of water supply pipes with different diameters as an adjusting unit and switch the water supply pipe through which water passes, from among the plurality of water supply pipes with different diameters, depending on the amount of water required, without using an adjusting valve.

[0104] In the first embodiment, the carbon dioxide capture system 1 adjusts the amount of water 35 sent to the storage unit 21 using the regulating valve 70 as an adjustment unit. However, the carbon dioxide capture system may be configured, for example, to use a water pump as an adjustment unit and arbitrarily adjust the amount of water pumped by the water pump from the storage tank according to the amount of water required, without using an adjustment valve. The control unit of the carbon dioxide capture system is configured to be able to send a signal related to the pumping amount to the water pump. The control unit controls the water pump to pump an arbitrary amount based on the amount of water required.

[0105] In the first embodiment, the carbon dioxide capture system 1 controls the water pump 32, the exhaust pump 52, the heating unit 40, and the regulating valve 70 in the carbon dioxide capture control shown in Fig. 6. However, the control of the water pump 32, the exhaust pump 52, the heating unit 40, and the regulating valve 70 does not have to be as shown in Fig. 6. It is sufficient that the water temperature is controlled using at least one of the regulating valve and the water pump.

[0106] In the first embodiment, the carbon dioxide capture system 1 uses water 35 as the heat medium. However, the heat medium may be a liquid mainly composed of mineral oil or synthetic oil, or an antifreeze liquid. The antifreeze liquid is, for example, a liquid mainly composed of ethylene glycol or propylene glycol. The heat medium may also be a liquid mainly composed of water mixed with a substance that lowers the freezing point of water. The heat medium may also be a liquid mainly composed of water mixed with a substance that raises the boiling point of water.

[0107] In the second embodiment, the carbon dioxide capture system 1B has two exterior bodies 20 and two module housings 10. However, the carbon dioxide capture system may have three or more exterior bodies and module housings.

[0108] In the second embodiment, the carbon dioxide capture system 1B controls two regulating valves 70, respectively, by two control units 90. However, a carbon dioxide capture system having a plurality of regulating valves may be configured to control the plurality of regulating valves by one control unit.

[0109] In the first and second embodiments, the heating unit 40 is configured to collect sunlight around the module housing 10 and irradiate the module housing 10 with the collected sunlight. However, the heating unit may be configured to collect sunlight at a position away from the module housing and guide the collected sunlight to the module housing by a reflector.

[0110] 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]

[0111] 1, 1A, 1B Carbon dioxide capture system 10 Module housing 11, 21 Storage unit 20 Exterior body 22 External surface 23 Inner surface 24 Insulated Room 30, 30B Heat medium supply section 31 Storage Tank 32 Water Pump 33, 33B Water pipe 34 Liquid level gauge 35 water 40 Heating section 41 Concave mirror 50, 50B Collection section 51 Carbon dioxide capture tank 52 Exhaust Pump 53, 53B Exhaust pipe 54 Carbon dioxide concentration meter 60 Temperature detection unit 70 Regulating valve 80, 80B circulation section 90, 90A Control section 101 Carbon dioxide capture module 102 Absorption section 102a Absorbing material 103 Filter section 104 Sealing part T1 Water temperature TH upper limit temperature C0 reference concentration C1 Carbon dioxide concentration

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; an exterior body that houses the module housing; A heat transfer medium covering the module housing; a heat medium supplying unit that supplies the heat medium between the module housing housed in the exterior housing and the exterior housing; a heating unit that heats the heat medium located between the module housing and the exterior body by sunlight; A recovery section that recovers carbon dioxide desorbed from the absorbent; a temperature detection unit that detects a temperature of the heat medium and is located between the module housing and the exterior body; A control unit that controls the heat medium supply unit, The control unit is a heat medium supply unit supplies new heat medium between the module housing housed in the exterior body and the exterior body based on the temperature of the heat medium inside the exterior body detected by the temperature detection unit, and controls the temperature of the heat medium located between the module housing housed in the exterior body and the exterior body. Carbon dioxide capture system.

2. 2. The carbon dioxide capture system according to claim 1, The heat medium supply unit includes: an adjusting unit that adjusts a flow rate of the heat medium supplied between the module housing housed in the exterior housing and the exterior housing; Carbon dioxide capture system.

3. The carbon dioxide recovery system according to claim 1 or 2, A plurality of the module housings; a plurality of the exterior bodies each housing a plurality of the module housings, The plurality of exterior bodies include connected in parallel to the heat medium supply unit, The heat medium supply unit includes: The heat medium can be supplied independently between the module housings housed in the respective exterior bodies and the exterior bodies. Carbon dioxide capture system.

4. The carbon dioxide recovery system according to claim 1 or 2, The heat medium supply unit includes: A storage tank for storing the heat medium; a pump that supplies the heat medium in the storage tank between the module housing housed in the exterior housing and the exterior housing, The heat medium supply unit includes: The heat medium in the storage tank is supplied between the module housing and the exterior body by the pump. Carbon dioxide capture system.

5. 5. The carbon dioxide recovery system according to claim 4, a circulation unit that returns the heat medium in the exterior body to the storage tank, The circulation section includes: When the volume of the heat medium in the exterior body exceeds a reference value, the heat medium exceeding the reference value is returned to the storage tank. Carbon dioxide capture system.

6. 2. The carbon dioxide capture system according to claim 1, The heat transfer medium is Oil, water, a mixture of water and a substance that depresses the freezing point of water, or antifreeze. Carbon dioxide capture system.

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