Adsorption member and carbon dioxide recovery system

Abstract

An adsorption member (50) comprises a base material (B) having a plurality of holes (56) through which air flows, and an adsorbent (60) that is supported by the base material (B) and adsorbs carbon dioxide in the air. The adsorbent (60) contains an amine-based substance and an ionic liquid.

Description

Adsorption material and carbon dioxide capture system

[0001] The present disclosure relates to an adsorption member and a carbon dioxide capture system.

[0002] There is a system for capturing carbon dioxide from the air. The carbon dioxide capture system described in Patent Document 1 includes an adsorption plate carrying an adsorbent and a flow pipe for heating the adsorption plate. Carbon dioxide in the air is adsorbed by the adsorbent. A heating medium flowing through the flow pipe heats and regenerates the adsorbent on the adsorption plate. The carbon dioxide desorbed from the adsorbent is transported by a pump and stored.

[0003] Japanese Patent Application Laid-Open No. 2023-13169

[0004] The temperature required to regenerate the adsorbent that adsorbs carbon dioxide is, for example, about 80 to 100° C. Therefore, if the temperature to which the adsorbent is heated is low, there is a problem in that the adsorbent cannot be sufficiently regenerated.

[0005] The present disclosure reduces the temperature required to regenerate adsorbents for carbon dioxide.

[0006] The first aspect relates to an adsorption member (50). The adsorption member (50) includes a substrate (B) having a plurality of holes (56) through which air flows, and an adsorbent (60) supported on the substrate (B) and configured to adsorb carbon dioxide in the air. The adsorbent (60) includes an amine-based substance and an ionic liquid.

[0007] In the first embodiment, the temperature required for regenerating the adsorbent (60) can be lowered by including an ionic liquid in the adsorbent (60).

[0008] In a second aspect, in the first aspect, the weight ratio of the ionic liquid to the amine-based substance is 1 / 3 or less.

[0009] If the weight ratio of the ionic liquid is too high, the temperature required for regenerating the adsorbent (60) becomes too low, and this temperature approaches the normal outdoor air temperature. As a result, the adsorption performance of the adsorbent (60) may be reduced, or carbon dioxide may be desorbed from the adsorbent (60) at an unintended timing. In contrast, in the second aspect, the weight ratio of the ionic liquid to the amine-based substance is ⅓ or less, so that the temperature required for regenerating the adsorption member (50) can be prevented from approaching the normal outdoor air temperature, thereby solving the above-mentioned problem.

[0010] A third aspect is the first or second aspect, wherein the weight ratio of the ionic liquid to the amine-based substance is 1 / 6 or more.

[0011] If the weight ratio of the ionic liquid is too small, it is not possible to sufficiently lower the temperature required for regenerating the adsorbent (60). In contrast, in the third aspect, by setting the weight ratio of the ionic liquid to 1 / 6 or more, it is possible to lower the temperature required for regenerating the adsorbent (60) below a normal temperature (e.g., 80 to 100°C).

[0012] A fourth aspect is a carbon dioxide recovery system including the adsorbing member (50) of any one of the first to third aspects.

[0013] In a fifth aspect, in the fourth aspect, the adsorption member (50) is further provided with a heating device (10) for heating the adsorption member (50) within a range of 50°C to 70°C.

[0014] In the fifth aspect, the temperature to which the adsorbing member (50) is heated by the heating device (10) is in the range of 50° C. to 70° C., which is lower than the normal temperature. In contrast, the temperature required to regenerate the adsorbing member (50) is lowered by the presence of the ionic liquid. Therefore, even if the temperature range to which the adsorbing member (50) is heated by the heating device (10) is relatively narrow, the adsorbent (60) can be regenerated.

[0015] In the sixth aspect, in the fifth aspect, the heating device (10) is a refrigeration cycle device having a compressor (13), a radiator (41), a pressure reduction mechanism (14), and an evaporator (15), and heating the adsorption member (50) by heat radiated from the radiator (41).

[0016] In a sixth aspect, the refrigeration cycle apparatus (10) heats the adsorbent (50) within a temperature range of 50°C to 70°C. When the refrigeration cycle apparatus (10) serves as a heat source for the adsorbent (60), if the temperature required for regenerating the adsorbent (60) is a normal temperature (e.g., 80°C to 100°C), the COP (coefficient of performance) of the refrigeration cycle apparatus (10) is likely to decrease. In contrast, the temperature required for regenerating the adsorbent (50) is decreased by the presence of an ionic liquid. Therefore, the adsorbent (60) can be regenerated while suppressing a decrease in the COP of the refrigeration cycle apparatus (10).

[0017] Fig. 1 is a diagram showing the overall configuration of a carbon dioxide capture system, and Fig. 2 is a schematic diagram showing an enlarged view of a main part of an adsorption member.

[0018] Hereinafter, embodiments of the present disclosure will be described in detail with reference to the drawings. Note that the present disclosure is not limited to the embodiments shown below, and various modifications are possible within the scope of the technical concept of the present disclosure. Since the drawings are intended to conceptually explain the present disclosure, dimensions, ratios, or numbers may be exaggerated or simplified as necessary to facilitate understanding.

[0019] (1) Overall Configuration An embodiment of the present disclosure is a carbon dioxide capture system (1). The carbon dioxide capture system (1) of this example captures carbon dioxide from the atmosphere, in other words, from the outdoor air. The carbon dioxide capture system (1) of this example constitutes a DAC (Direct Air Capture) system that separates and captures carbon dioxide directly from the atmosphere.

[0020] As shown in Fig. 1, the carbon dioxide capture system (1) includes a refrigeration cycle device (10), an adsorption device (30) having an adsorption member (50), a capture unit (20), and a controller (C). The refrigeration cycle device (10) is a heating device that heats the adsorption member (50). The capture unit (20) is a device that captures carbon dioxide desorbed from the adsorption member (50). The controller (C) controls each device of the carbon dioxide capture system (1).

[0021] (2) Refrigeration Cycle Device The refrigeration cycle device (10) includes a refrigerant circuit (11) that performs a refrigeration cycle and a first fan (12). The refrigerant circuit (11) is filled with refrigerant. The refrigerant circuit (11) includes a compressor (13), a first heat exchanger (41), an expansion valve (14), and a second heat exchanger (15). The compressor (13) compresses and discharges the refrigerant. The compressor (13) is configured to have a variable rotation speed. The first heat exchanger (41) constitutes a radiator (condenser). The first heat exchanger (41) is provided in the adsorption device (30). The first heat exchanger (41) exchanges heat between the refrigerant and the adsorption member (50) to heat the adsorption member (50). The expansion valve (14) constitutes a pressure reduction mechanism that reduces the pressure of the refrigerant. For example, the expansion valve (14) is configured as an electronic expansion valve with a variable opening. The second heat exchanger (15) is an air heat exchanger located outside the room. The first fan (12) is located near the second heat exchanger (15). The second heat exchanger (15) exchanges heat between the refrigerant and the outdoor air blown by the first fan (12).

[0022] (3) Adsorption Device The adsorption device (30) has a casing (31), an inlet duct (32), and an outlet duct (33).

[0023] The casing (31) is hollow and defines an air flow path (AP) therein through which air flows. The casing (31) has a first plate (31a) and a second plate (31b). The first plate (31a) and the second plate (31b) face each other. In this example, the first plate (31a) is located on the lower side of the casing (31), and the second plate (31b) is located on the upper side of the casing (31).

[0024] The casing (31) is formed with an inlet (34) through which outdoor air flows into the air flow path (AP) and an outlet (35) through which air in the air flow path (AP) flows out. The inlet (34) is formed in the first plate (31a). The outlet (35) is formed in the second plate (31b). The air flow path (AP) is formed from the inlet (34) to the outlet (35).

[0025] The inlet duct (32) is connected to the inlet (34). The inlet duct (32) connects the outdoor space with the inlet (34). A first damper (36) is provided inside the inlet duct (32). The first damper (36) is switchable between an open state (shown by a solid line in FIG. 1 ) in which the inlet (34), which is the inlet portion of the air flow path (AP), is opened, and a closed state (shown by a dashed line in FIG. 1 ) in which the inlet (34) is closed.

[0026] The outlet duct (33) is connected to the outlet (35). The outlet duct (33) connects the outlet (35) to the outdoor space. A second damper (37) is provided inside the outlet duct (33). The second damper (37) is switchable between an open state (shown by a solid line in FIG. 1 ) in which the outlet (35), which is the outlet portion of the air flow path (AP), is opened, and a closed state (shown by a dashed line in FIG. 1 ) in which the outlet (35) is closed.

[0027] The adsorption device (30) includes an adsorption unit (40) and a second fan (38). The adsorption unit (40) and the second fan (38) are arranged in the air flow path (AP). In this example, the second fan (38) is arranged downstream of the adsorption unit (40) in the air flow direction. The second fan (38) transports air in the air flow path (AP).

[0028] The adsorption unit (40) includes a first heat exchanger (41) and an adsorption member (50). The adsorption unit (40) is configured by attaching the adsorption member (50) to the first heat exchanger (41). As shown schematically in FIG. 2 , the adsorption member (50) includes a substrate (B) and an adsorbent (B) supported on the substrate (B). The substrate (B) has a plurality of holes (56) through which air flows. The adsorbent (60) is supported on the inner surfaces of the plurality of holes (56). The adsorbent (60) may be supported on the outer surface of the substrate (B).

[0029] The adsorbent (60) has the property of adsorbing carbon dioxide. Strictly speaking, the higher the temperature of the adsorbent (60), the easier it is for carbon dioxide to be desorbed, and the lower the temperature, the easier it is for carbon dioxide to be adsorbed. Here, "adsorption" includes not only the adsorption of carbon dioxide onto the surface of a solid or liquid, but also the absorption of carbon dioxide into the interior of a solid or liquid. Furthermore, "adsorption" includes not only physical adsorption but also chemical adsorption. The adsorbent (60) is formed of a liquid film.

[0030] (4) Recovery Unit As shown in FIG. 1 , the recovery unit (20) includes a recovery flow path (21), a tank (22), a pump (23), and an on-off valve (24). The inlet end of the recovery flow path (21) is connected to the casing (31). The inlet end of the recovery flow path (21) is connected to the air flow path (AP). The outlet end of the recovery flow path (21) is connected to the tank (22). The tank (22) stores the recovered carbon dioxide. The pump (23) reduces the pressure inside the casing (31) and transports the carbon dioxide desorbed from the adsorption member (50). The on-off valve (24) is provided in the recovery flow path (21) and opens and closes the recovery flow path (21). The recovery unit (20) may include a damper that opens and closes the recovery flow path (21) instead of the on-off valve (24).

[0031] (5) Controller As shown in Fig. 1, the controller (C) controls the refrigeration cycle apparatus (10), the adsorption device (30), and the recovery unit (20). Specifically, the controller (C) controls the open / close states of the first damper (36) and the second damper (37), the ON / OFF states of the first fan (12) and the second fan (38), the ON / OFF state of the compressor (13), the rotation speed of the compressor (13), the opening degree of the expansion valve (14), the ON / OFF state of the pump (23), and the open / close state of the on-off valve (24). The controller (C) may control the rotation speed of the first fan (12), the second fan (38), or the pump (23).

[0032] The controller (C) comprises a microcomputer and a memory device that stores software for operating the microcomputer.

[0033] (6) Operation of the Carbon Dioxide System The carbon dioxide capture system (1) performs an adsorption operation as a first operation and a regeneration operation as a second operation. The carbon dioxide capture system (1) alternately repeats the adsorption operation and the regeneration operation at predetermined time intervals.

[0034] (6-1) Adsorption Operation In the adsorption operation, the first damper (36) and the second damper (37) are in an open state (the state indicated by the solid line in FIG. 1), and the on-off valve (24) is in a closed state. The compressor (13), the first fan (12), and the pump (23) are stopped, and the second fan (38) is in an operating state. The refrigeration cycle apparatus (10) does not perform a refrigeration cycle.

[0035] When the second fan (38) is operated, outdoor air passes through the inlet duct (32) and the inlet (34) in this order, and flows through the air flow path (AP) in the casing (31). The air in the air flow path (AP) flows through the through-holes (56) of the adsorption member (50). At this time, carbon dioxide in the air is adsorbed by the adsorbent (60). The air that has flowed out of the through-holes (56) and passed through the adsorption unit (40) passes through the outlet (35) and the outlet duct (33) in this order, and is discharged to the outside of the room.

[0036] (6-2) Regeneration Operation In the regeneration operation, the first damper (36) and the second damper (37) are closed (as indicated by the dashed lines in FIG. 1 ), and the on-off valve (24) is opened. The compressor (13), the first fan (12), and the pump (23) are in operation, and the second fan (38) is stopped. The refrigeration cycle apparatus (10) performs a refrigeration cycle in which the first heat exchanger (41) functions as a radiator (condenser) and the second heat exchanger (15) functions as an evaporator.

[0037] In the refrigerant circuit (11), the compressor (13) compresses the refrigerant and discharges the compressed refrigerant. The refrigerant discharged from the compressor (13) flows through the first heat exchanger (41). Specifically, in the first heat exchanger (41), the refrigerant in the first header collecting pipe (42) is divided into the flat tubes (44). The heat of the refrigerant in each flat tube (44) is transferred to the adsorption section (51). As a result, carbon dioxide adsorbed in the adsorbent (60) is desorbed. The refrigerant that flows through the flat tubes (44) and condenses is joined in the second header collecting pipe (43) and then decompressed by the expansion valve (14). The decompressed refrigerant absorbs heat from the outdoor air in the second heat exchanger (15) and evaporates. The evaporated refrigerant is compressed again by the compressor (13).

[0038] When the pump (23) is operated, the pressure in the air flow path (AP) of the casing (31) is reduced. When carbon dioxide is desorbed from the adsorption member (50), the carbon dioxide concentration in the air in the air flow path (AP) increases. In this manner, the concentrated carbon dioxide flows through the recovery flow path (21) and is recovered in the tank (22).

[0039] In the regeneration operation, the refrigeration cycle apparatus (10) is configured to heat the adsorption member (50) to a temperature in the range of 50° C. to 70° C. Specifically, in the regeneration operation, the controller (C) adjusts the temperature of the refrigerant in the first heat exchanger (41) by controlling the rotation speed of the compressor (13). At this time, the controller (C) may control the opening of the expansion valve (14).

[0040] (7) Adsorbent Material The adsorbent (60) of this embodiment is composed of a material including two components, an amine-based substance that adsorbs carbon dioxide and an ionic liquid, or a material including three or more components including an amine-based substance and an ionic liquid. Strictly speaking, the amine-based substance is an amine-based liquid. The amine-based liquid is polyethyleneimine.

[0041] The amine-based liquid may be 3-aminopropyltriethoxysilane, 3-[2-(2-aminoethylamino)ethylamino]propyltrimethoxysilane, 3-(2-aminoethylamino)propyldimethoxymethylsilane, 3-(aminomethyl)benzylamine, 2-amino-2-methyl-1-propanol, 2-amino-2-methyl-1,3-propanediol, 2-amino-2-hydroxymethyl-1,3-propanediol, 2-hydroxyethyldimethylamine, 1-amino-2-propanol, 1-amino-2-butanol, tetraethylenepentamine, benzylamine, phenethylamine, paramethoxybenzylamine, metaxylenediamine, hydroxyxylenediamine, monoethanolamine, diethylene glycolamine, dimethylaminoethanol, and the like.

[0042] The ionic liquids were 1-butyl-3-methylimidazolium hexafluorophosphate, 1-butyl-3-methylimidazolium nitrate, 1-butyl-3-methylimidazolium tetrafluoroborate, 1-ethyl-3-methylimidazolium dicyanamide, 1-butyl-3-methylimidazolium thiocyanate, 1-butyl-3-methylimidazolium methylsulfate, and 1-butyl-3-methylimidazolium trifluoromethanesulfonate. nitrate, 1-butyl-3-methylimidazolium acetate, 1-ethyl-1-3-methyl-1-imidazolium ethyl sulfate, 1-n-octyl-3-methylimidazolium hexafluorophosphate, 1-n-octyl-1-3-methylimidazolium tetrafluoroborate, 1-n-butyl-3-methylimidazolium nitrate, N-butylpyridinium tetrafluoroborate, 1-butyl-3-methylimidazolium, and the like.

[0043] When the adsorbent is composed of only an amine-based liquid, the temperature required for regenerating the adsorbent (60) is approximately 80° C. to 100° C. In this case, the adsorption member (50) needs to be heated to a temperature in the range of 80° C. to 100° C. In the refrigeration cycle apparatus (10), if the temperature of the refrigerant in the first heat exchanger (41) is set to a temperature above this temperature range, the COP (coefficient of performance) of the refrigeration cycle apparatus (10) will decrease.

[0044] In contrast, the adsorbent (60) of this embodiment contains an ionic liquid in addition to an amine-based liquid. This allows the temperature required for regenerating the adsorbent (60) to be lowered during the regeneration operation. The presence of the ionic liquid reduces the C—N bond strength of the carbamate / carbamic acid species, which in turn makes it easier for carbon dioxide adsorbed in the adsorbent (60) to be desorbed. This allows the temperature required for regenerating the adsorbent (60) to be lowered.

[0045] The weight of the amine liquid in the adsorbent (60) is represented by w1, and the weight of the ionic liquid is represented by w2. In this case, the weight ratio of the ionic liquid to the amine liquid (w2 / w1) is preferably 1 / 3 or less. If the weight ratio of the ionic liquid becomes too large, the temperature required for regenerating the adsorbent (60) becomes excessively low. Specifically, the temperature required for regenerating the adsorbent (60) becomes less than 50°C. In this case, under conditions where the outdoor air temperature is high, such as in summer, the adsorbent (60) may spontaneously regenerate. Furthermore, the adsorption capacity of the adsorbent (60) may decrease, which may result in insufficient capture of carbon dioxide from the air.

[0046] In contrast, in the adsorbent (60) of this embodiment, the weight ratio (w2 / w1) of the ionic liquid to the amine-based liquid is ⅓ or less. This prevents the temperature required for regenerating the adsorbent (60) from falling below 50°C. As a result, it is possible to prevent the adsorbent (60) from being spontaneously regenerated by outdoor air and to prevent the adsorption capacity of the adsorbent (60) from decreasing.

[0047] The weight ratio of the ionic liquid to the amine-based liquid (w2 / w1) is preferably 1 / 6 or more. If the weight ratio of the ionic liquid is too small, the temperature required for regenerating the adsorbent (60) cannot be sufficiently reduced. This increases the energy required to heat the adsorbent (60). In particular, the COP of the refrigeration cycle device (10) decreases.

[0048] In contrast, the adsorbent (60) of this embodiment has a weight ratio (w2 / w1) of ionic liquid to amine liquid of 1 / 6 or more. This allows the temperature required for regenerating the adsorbent (60) to be reduced to approximately 70°C or less. As a result, the energy required for regenerating the adsorbent (60) can be reduced, and the COP of the refrigeration cycle apparatus (10) can be improved.

[0049] (8) Features (8-1) The adsorption member (50) includes a substrate (B) having a plurality of holes (56) through which air flows, and an adsorbent (60) supported on the substrate (B) and configured to adsorb carbon dioxide in the air. The adsorbent (60) includes an amine-based liquid and an ionic liquid.

[0050] In this configuration, the presence of the ionic liquid can reduce the temperature required to regenerate the adsorbent (60), thereby reducing the energy required to regenerate the adsorbent (60).

[0051] When the regeneration temperature of the adsorbent (60) increases, the amine-based liquid becomes more likely to volatilize, shortening the life of the adsorbent (60). In contrast, when the regeneration temperature of the adsorbent (60) decreases due to the presence of the ionic liquid, the amine-based liquid becomes less likely to volatilize. As a result, the life of the adsorbent (60) increases, and the frequency of replacement of the adsorbent (60) can be reduced.

[0052] (8-2) The adsorbent (60) is configured so that the weight ratio of the ionic liquid to the amine-based substance is 1 / 3 or less. This prevents the temperature required for regenerating the adsorbent (60) from becoming excessively low, thereby preventing carbon dioxide from spontaneously regenerating from the adsorbent (60) and preventing a decrease in the adsorption performance of the adsorbent (60).

[0053] (8-3) The adsorbent (60) is configured so that the weight ratio of the ionic liquid to the amine-based substance is 1 / 6 or more. This allows the temperature required for regeneration of the adsorbent (60) to be sufficiently low, thereby reducing the energy required for regeneration.

[0054] (8-4) The carbon dioxide recovery system (1) includes a heating device that heats the adsorption member (50) to a temperature in the range of 50° C. to 70° C. The heating device is a refrigeration cycle apparatus (10) that includes a compressor (13), a first heat exchanger (41) that serves as a radiator, an expansion valve (14) that serves as a pressure reduction mechanism, and a second heat exchanger (15) that serves as an evaporator, and that heats the adsorption member (50) with heat released from the first heat exchanger.

[0055] The presence of the ionic liquid allows the temperature required for regenerating the adsorbent (60) to be in the range of 50° C. to 70° C. In contrast, the refrigeration cycle apparatus (10) is configured to heat the adsorption member (50) in the range of 50° C. to 70° C., so that carbon dioxide can be sufficiently desorbed from the adsorbent (60). The lower regeneration temperature of the adsorbent (60) can improve the COP of the refrigeration cycle apparatus (10).

[0056] (8-5) The adsorption member (50) has a substrate (B) having a plurality of holes (56) through which air flows, and an adsorbent (60) supported on the substrate (B). Therefore, the surface area of ​​the adsorption member (50) on which the adsorbent (60) is supported can be increased, thereby increasing the adsorption capacity of the adsorption unit (40).

[0057] Here, if the regeneration temperature of the adsorbent (60) is lowered due to the presence of an ionic liquid, the adsorption capacity of the adsorbent (60) may decrease, and the adsorbent (60) may not be able to adsorb a sufficient amount of carbon dioxide. In contrast, by supporting the adsorbent (60) on a substrate (B) having a plurality of holes (56), such a decrease in the adsorption capacity can be suppressed.

[0058] (9) Other Embodiments The above embodiment may have the following configurations.

[0059] The carbon dioxide capture system (1) does not have to be a DAC system that directly captures carbon dioxide from the atmosphere. For example, the carbon dioxide capture system (1) may capture carbon dioxide from a mixture of air and industrial exhaust gases.

[0060] The heating device may be an electric heater or a heat source utilizing exhaust heat. The heating device may be a hot water supply device that supplies high-temperature water as a heat medium to the heat transfer tubes (flat tubes (44)) of the adsorption unit (40). In other words, the carbon dioxide capture system (1) does not need to use the refrigeration cycle device (10) as a heat source.

[0061] The pressure reducing mechanism may be a capillary tube or a temperature-sensitive expansion valve.

[0062] The adsorbing member (50) may adsorb carbon dioxide in the room air instead of the outdoor air. The adsorbing member (50) may be applied to, for example, a ventilation system for ventilating a room.

[0063] The adsorbent (60) may be supported over the entire substrate (B).

[0064] The material of the substrate (B) of the adsorption member (50) may be metal. The substrate (B) may be made of a porous material. In this case, the pores inside the porous material form the holes through which air flows. The substrate (B) may be made of metal fiber or carbon fiber. In this case, the pores inside the metal fiber or carbon fiber form the holes through which air flows.

[0065] Although the embodiments and modifications have been described above, it will be understood that various modifications in form and details are possible without departing from the spirit and scope of the claims. Furthermore, the above embodiments, modifications, and other embodiments may be combined or substituted as appropriate as long as the functionality of the subject matter of the present disclosure is not impaired.

[0066] The above-mentioned descriptions such as "first," "second," "third," etc. are used to distinguish the words to which these descriptions are attached, and do not limit the number or order of the words.

[0067] As described above, the present disclosure is useful for adsorption members and carbon dioxide recovery systems.

[0068] REFRACTORY OF SYMBOLS 1 Carbon dioxide recovery system 10 Refrigeration cycle device (heating device) 13 Compressor 14 Expansion valve (pressure reducing mechanism) 15 Second heat exchanger (evaporator) 41 First heat exchanger (radiator) 50 Adsorption member 56 Through-hole (hole) 60 Adsorbent B Substrate

Claims

1. An adsorption member comprising: a substrate (B) having a plurality of holes (56) through which air flows; and an adsorbent (60) supported on the substrate (B) and configured to adsorb carbon dioxide in the air, the adsorbent (60) including an amine-based substance and an ionic liquid.

2. The adsorption member according to claim 1 or 2, wherein the weight ratio of the ionic liquid to the amine-based substance is 1 / 3 or less.

3. The adsorption member according to claim 2, wherein the weight ratio of the ionic liquid to the amine-based substance is 1 / 6 or more.

4. A carbon dioxide recovery system comprising the adsorption member according to any one of claims 1 to 3.

5. The carbon dioxide capture system according to claim 4, further comprising a heating device (10) for heating the adsorption member (50) to a temperature in the range of 50°C or higher and 70°C or lower.

6. The carbon dioxide recovery system according to claim 5, wherein the heating device (10) is a refrigeration cycle device having a compressor (13), a radiator (41), a pressure reduction mechanism (14), and an evaporator (15), and heats the adsorption member (50) by heat released from the radiator (41).

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