Carbon dioxide capture system

Abstract

To provide a carbon dioxide recovery system capable of reducing power consumption when suctioning a carbon dioxide adsorption tank. [Solution] The carbon dioxide capture system 2 includes a blower 22, carbon dioxide adsorption tanks 531, 532 that contain a carbon dioxide adsorbent that adsorbs carbon dioxide contained in the air sent from the blower 22, and suction means 581 that sucks in concentrated gas containing carbon dioxide desorbed from the carbon dioxide adsorbent. Before the suction means 581 sucks in the concentrated gas, a predetermined amount of air present in the internal space of the carbon dioxide adsorption tanks 531, 532 that contains the carbon dioxide adsorbent is discharged by contracting the volume of the internal space. After the predetermined amount of air has been discharged, the suction means 581 sucks in the concentrated gas.

Description

[Technical Field]

[0001] The present invention relates to a carbon dioxide capture system that captures carbon dioxide directly from the atmosphere. [Background technology]

[0002] Patent Document 1 discloses a carbon dioxide capture system that captures carbon dioxide directly from the atmosphere. In the carbon dioxide capture system described in Patent Document 1, air is sucked into an air pump and discharged from the air pump, passes through a moisture remover, and is then guided to a carbon dioxide capture device.

[0003] The pretreated gas guided from the moisture removal device to the carbon dioxide capture device is guided at a predetermined timing to a carbon dioxide adsorption tank containing a carbon dioxide adsorbent and passes through the carbon dioxide adsorption tank. As the pretreated gas passes through the carbon dioxide adsorption tank, the carbon dioxide contained in the pretreated gas is adsorbed by the carbon dioxide adsorbent contained in the carbon dioxide adsorption tank.

[0004] The carbon dioxide adsorption tank is evacuated by a vacuum pump at a predetermined timing. As a result, the carbon dioxide adsorbed in the carbon dioxide adsorbent is desorbed from the carbon dioxide adsorbent. The desorbed gas containing carbon dioxide is led as a concentrated gas to a storage section that stores carbon dioxide.

[0005] Here, in the initial stage of the process of vacuum suction of the carbon dioxide adsorption tank by the vacuum pump, the air present in the internal space of the carbon dioxide adsorption tank is first discharged. In other words, in the initial stage of the process of vacuum suction of the carbon dioxide adsorption tank by the vacuum pump, almost no carbon dioxide adsorbed in the carbon dioxide adsorbent is released from the carbon dioxide adsorbent. Thereafter, when the degree of vacuum in the internal space of the carbon dioxide adsorption tank reaches a predetermined value or higher, the carbon dioxide adsorbed in the carbon dioxide adsorbent is released from the carbon dioxide adsorbent.

[0006] Therefore, a relatively large amount of power is required when the vacuum pump draws a vacuum from the carbon dioxide adsorption tank. In other words, when the vacuum pump draws a vacuum from the carbon dioxide adsorption tank, additional power is required to expel the air present in the internal space of the carbon dioxide adsorption tank. In this respect, there is room for improvement in the carbon dioxide capture system described in Patent Document 1. [Prior art documents] [Patent documents]

[0007] [Patent Document 1] Patent No. 7507533 Summary of the Invention [Problem to be solved by the invention]

[0008] The present invention has been made in consideration of the above circumstances, and aims to provide a carbon dioxide recovery system that can reduce power consumption when sucking in concentrated gas containing carbon dioxide that has been desorbed from a carbon dioxide adsorbent. [Means for solving the problem]

[0009] One aspect of the present invention is a carbon dioxide capture system that captures carbon dioxide directly from the atmosphere, comprising: a blower that sends in air; a carbon dioxide adsorption tank that contains a carbon dioxide adsorbent that adsorbs the carbon dioxide contained in the air sent in from the blower; and suction means that sucks in concentrated gas containing the carbon dioxide that has desorbed from the carbon dioxide adsorbent and directs the concentrated gas toward a storage section that stores the carbon dioxide, wherein before the suction means sucks in the concentrated gas, a volume of the internal space of the carbon dioxide adsorption tank that houses the carbon dioxide adsorbent is contracted to discharge a predetermined amount of the air present in the internal space, and after the predetermined amount of the air has been discharged, the suction means sucks in the concentrated gas.

[0010] According to one aspect of the present invention, before the suction means draws in concentrated gas containing carbon dioxide desorbed from the carbon dioxide adsorbent, the volume of the internal space of the carbon dioxide adsorption tank containing the carbon dioxide adsorbent is first contracted, thereby discharging a predetermined amount of air present in the internal space of the carbon dioxide adsorption tank. Then, after the predetermined amount of air has been discharged from the carbon dioxide adsorption tank, the suction means draws in the concentrated gas. This prevents the suction means from consuming unnecessary power to discharge the air present in the internal space of the carbon dioxide adsorption tank. As a result, the carbon dioxide capture system according to one aspect of the present invention can reduce power consumption when drawing in concentrated gas containing carbon dioxide desorbed from the carbon dioxide adsorbent. [Effects of the Invention]

[0011] According to the present invention, it is possible to provide a carbon dioxide recovery system that can reduce power consumption when sucking concentrated gas containing carbon dioxide desorbed from a carbon dioxide adsorbent. [Brief explanation of the drawings]

[0012] [Figure 1] 1 is a system diagram illustrating a carbon dioxide capture system according to an embodiment of the present invention. [Figure 2] FIG. 2 is a schematic diagram showing a first carbon dioxide adsorption tank and a second carbon dioxide adsorption tank of the present embodiment. [Figure 3] 4 is a timing chart illustrating the operation of the carbon dioxide capture system according to the present embodiment. DETAILED DESCRIPTION OF THE INVENTION

[0013] Hereinafter, an embodiment of the present invention will be described with reference to the drawings. The embodiments described below are preferred examples of the present invention, and therefore various technically preferable limitations are applied thereto, but the scope of the present invention is not limited to these aspects unless otherwise specified in the following description to the effect that the present invention is particularly limited. Furthermore, in each drawing, similar components are designated by the same reference numerals, and detailed descriptions thereof will be omitted as appropriate.

[0014] FIG. 1 is a system diagram showing a carbon dioxide capture system according to an embodiment of the present invention. The carbon dioxide capture system 2 according to this embodiment is a system that captures carbon dioxide directly from the atmosphere. The carbon dioxide capture system 2 includes a blower 22, a carbon dioxide capture device 5, and a control device 6. The number of carbon dioxide capture devices may be one or two or more. For ease of explanation, the blower 22, the carbon dioxide capture device 5, and the control device 6 are shown in FIG. 1 as separate entities. However, the blower 22, the carbon dioxide capture device 5, and the control device 6 may also be provided integrally with one another.

[0015] The blower 22 sends atmospheric air to the carbon dioxide capture device 5. The carbon dioxide capture device 5 is provided downstream of the blower 22 and is a device that adsorbs carbon dioxide from the air sent from the blower 22. The carbon dioxide capture device 5 may adsorb carbon dioxide from pretreated gas from which moisture contained in the air has been removed.

[0016] 1, the carbon dioxide capture device 5 includes a first intake valve 511, a second intake valve 512, a first exhaust valve 521, a second exhaust valve 522, a first carbon dioxide adsorption tank 531, a second carbon dioxide adsorption tank 532, a first pressure sensor 541, a second pressure sensor 542, a first check valve 551, a second check valve 552, a throttle valve 561, a three-way valve 523, a flow meter 524, a filter 571, and a vacuum pump 581. Each of the first carbon dioxide adsorption tank 531 and the second carbon dioxide adsorption tank 532 of this embodiment is an example of the "carbon dioxide adsorption tank" of the present invention. The vacuum pump 518 of this embodiment is an example of the "suction means" of the present invention.

[0017] The first carbon dioxide adsorption tank 531 contains a first carbon dioxide adsorbent. The first carbon dioxide adsorbent is, for example, zeolite, and adsorbs carbon dioxide from the air sent from the blower 22. The second carbon dioxide adsorption tank 532 contains a second carbon dioxide adsorbent. The second carbon dioxide adsorbent is, for example, zeolite, and adsorbs carbon dioxide from the air sent from the blower 22. Each of the first carbon dioxide adsorbent and the second carbon dioxide adsorbent of this embodiment is an example of the "carbon dioxide adsorbent" of the present invention.

[0018] The first pressure sensor 541 detects the pressure inside the first carbon dioxide adsorption tank 531 and transmits a signal related to the pressure inside the first carbon dioxide adsorption tank 531 to the control device 6. The second pressure sensor 542 detects the pressure inside the second carbon dioxide adsorption tank 532 and transmits a signal related to the pressure inside the second carbon dioxide adsorption tank 532 to the control device 6.

[0019] 1, the control device 6 has a calculation unit 61 and a storage unit 62, and transmits signals to each valve provided in the carbon dioxide capture device 5 to control the operation of each valve. The control device 6 also receives signals from each sensor and each measuring instrument provided in the carbon dioxide capture device 5.

[0020] The calculation unit 61 is, for example, a CPU (Central Processing Unit) or a GPU (Graphics Processing Unit), and executes program startup, signal control processing, calculations, drive control of a display unit (not shown), etc. based on signals (commands) transmitted from an operation unit (not shown). In other words, the calculation unit 61 controls the entire carbon dioxide capture system 2.

[0021] The storage unit 62 stores sequence programs for executing control to adsorb carbon dioxide from the air in the carbon dioxide capture device 5, programs for integrally managing these sequence programs, etc. The storage unit 62 also stores various data such as measurement data.

[0022] Examples of the storage unit 62 include a semiconductor memory or a hard disk drive (HDD: Hard Disk Drive) built into the carbon dioxide capture system 2. Alternatively, examples of the storage unit 62 include various storage media and storage devices connectable to the carbon dioxide capture system 2, such as a CD (Compact Disc), a DVD (Digital Versatile Disc), a RAM (Random Access Memory), a ROM (Read Only Memory), an SSD (Solid State Drive), a hard disk, and a memory card. Alternatively, the storage unit 62 may be online storage connected via a network such as the Internet.

[0023] Vacuum pump 518 sucks in concentrated gas containing carbon dioxide that has been desorbed from the first carbon dioxide adsorbent and the second carbon dioxide adsorbent, and directs the sucked concentrated gas toward storage section 7. Note that the means for sucking in concentrated gas, i.e., the "suction means" of the present invention, is not limited to vacuum pump 518. The suction means does not necessarily need to create a vacuum inside first carbon dioxide adsorption tank 531 and second carbon dioxide adsorption tank 532, and may be a pump other than a vacuum pump or a fan as long as it can direct the sucked concentrated gas toward storage section 7. In the following explanation, an example will be given in which the suction means is vacuum pump 518.

[0024] FIG. 2 is a schematic diagram showing the first carbon dioxide adsorption tank and the second carbon dioxide adsorption tank of this embodiment. In the carbon dioxide capture system 2 according to this embodiment, the structure of the first carbon dioxide adsorption tank 531 is similar to the structure of the second carbon dioxide adsorption tank 532. Therefore, in this embodiment, the structure of the carbon dioxide adsorption tank will be described using the first carbon dioxide adsorption tank 531 as an example.

[0025] 2, first carbon dioxide adsorption tank 531 accommodates first carbon dioxide adsorbent 535 in internal space 531S. That is, internal space 531S is the space inside first carbon dioxide adsorption tank 531 that accommodates first carbon dioxide adsorbent 535. First carbon dioxide adsorbent 535 has a structure that is expandable and contractable in direction A1, in which air present in internal space 531S is discharged, and in direction A2, in which air introduced into first carbon dioxide adsorption tank 531 passes through first carbon dioxide adsorption tank 531.

[0026] 2 is the direction from the first carbon dioxide adsorption tank 531 to the first flow path 231 (see FIG. 1). As shown in FIG. 1, the first flow path 231 is a flow path that connects the first carbon dioxide adsorption tank 531 and the second carbon dioxide adsorption tank 532 to the three-way valve 523. Moreover, the direction A2 shown in FIG. 2 is the direction from the first carbon dioxide adsorption tank 531 to the fourth flow path 234 (see FIG. 1). As shown in FIG. 1, the fourth flow path 234 is a flow path that connects the throttle valve 561 to the outside of the carbon dioxide capture device 5 (specifically, the atmosphere).

[0027] First carbon dioxide adsorption tank 531 further includes partition plate 536. Partition plate 536 is provided inside first carbon dioxide adsorption tank 531 and can move in directions A1 and A2 shown in Fig. 2. For example, partition plate 536 moves in direction A1 shown in Fig. 2 or in direction A2 shown in Fig. 2 based on a control signal transmitted from calculation unit 61 of control device 6.

[0028] 2, the volume of internal space 531S of first carbon dioxide adsorption tank 531 contracts. As a result, the air present in internal space 531S is guided in direction A1 shown in FIG. 2 and discharged to the outside of first carbon dioxide adsorption tank 531. Furthermore, first carbon dioxide adsorbent 535 accommodated in internal space 531S contracts in direction A1 shown in FIG. 2.

[0029] 2, the volume of internal space 531S of first carbon dioxide adsorption tank 531 expands. As a result, first carbon dioxide adsorbent 535 housed in internal space 531S expands or expands in direction A2 shown in FIG.

[0030] Next, the operation of the carbon dioxide capture system 2 according to this embodiment will be described with reference to the drawings. FIG. 3 is a timing chart illustrating the operation of the carbon dioxide capture system according to this embodiment.

[0031] 3 indicates the open state of each valve at each timing (T1 to T6), the connected state (i.e., the communicating state) of the three-way valve 523 at each timing, and the operating state of each pump at each timing. Timings T1 to T6 are arranged in chronological order. When control at timing T6 is completed, control at timing T1 is executed again. In other words, control at timings T1 to T6 is repeatedly executed in this order.

[0032] First, as shown in Fig. 1, blower 22 sucks in the atmosphere (i.e., air) through filter 21 and sends the sucked air to carbon dioxide capture device 5. As shown in Fig. 3, blower 22 is constantly operating at times T1 to T6. The air sent by blower 22 to carbon dioxide capture device 5 contains carbon dioxide.

[0033] The air guided from the blower 22 to the carbon dioxide capture device 5 is guided to at least one of the first carbon dioxide adsorption tank 531 and the second carbon dioxide adsorption tank 532 according to the timing of control.

[0034] 3, the first intake valve 511 is open, and the second intake valve 512 is closed. In this case, air guided from the blower 22 to the carbon dioxide capture device 5 is guided to the first carbon dioxide adsorption tank 531 and passes through the first carbon dioxide adsorption tank 531. As the air passes through the first carbon dioxide adsorption tank 531, the carbon dioxide contained in the air is adsorbed by the first carbon dioxide adsorbent 535 (see FIG. 2) housed in the first carbon dioxide adsorption tank 531. At this time, the volume of the internal space 531S of the first carbon dioxide adsorption tank 531 expands.

[0035] Also, at timing T1, first exhaust valve 521 is closed. Therefore, the gas that has had carbon dioxide adsorbed by first carbon dioxide adsorbent 535 and passed through first carbon dioxide adsorption tank 531 passes through first check valve 551 and throttle valve 561 as captured gas, flows through fourth flow path 234, and is released into the atmosphere. As shown in Fig. 1, fourth flow path 234 is a flow path that connects throttle valve 561 to the outside of carbon dioxide capture device 5 (specifically, the atmosphere).

[0036] Furthermore, at timing T1, the second exhaust valve 522 is open. Furthermore, the three-way valve 523 is set to a first state. The first state of the three-way valve 523 is a state in which the three-way valve 523 connects the first flow path 231 (see FIG. 1) and the second flow path 232 (see FIG. 1). The first flow path 231 is a flow path that connects the first carbon dioxide adsorption tank 531 and the second carbon dioxide adsorption tank 532 with the three-way valve 523. The second flow path 232 is a flow path that connects the three-way valve 523 with the outside of the carbon dioxide capture device 5 (specifically, the atmosphere).

[0037] In this state, as indicated by arrow A3 in Fig. 2, partition plate 538 (see Fig. 2) of second carbon dioxide adsorption tank 532 moves in direction A1 in Fig. 2. This causes the volume of internal space 532S (see Fig. 2) of second carbon dioxide adsorption tank 532, in which second carbon dioxide adsorbent 537 (see Fig. 2) is accommodated, to contract. As a result, air present in internal space 532S is discharged to the outside of second carbon dioxide adsorption tank 532 in direction A1 in Fig. 2. The air discharged to the outside of second carbon dioxide adsorption tank 532 flows through first flow path 231 and second flow path 232 and is discharged into the atmosphere.

[0038] Subsequently, after a predetermined amount of air present in internal space 532S of second carbon dioxide adsorption tank 532 is discharged into the atmosphere, vacuum pump 581 is operated at timing T2 shown in FIG. 3. Also, three-way valve 523 is changed from its first state to its second state. The second state of three-way valve 523 is a state in which three-way valve 523 connects first flow path 231 and third flow path 233 (see FIG. 1). Third flow path 233 is a flow path that connects three-way valve 523 and vacuum pump 581. Therefore, at timing T2, vacuum pump 581 vacuums second carbon dioxide adsorption tank 532 via filter 571.

[0039] As a result, the carbon dioxide adsorbed to second carbon dioxide adsorbent 537 is released. The gas containing the released carbon dioxide flows as concentrated gas through first flow path 231 and third flow path 233 and is led to storage unit 7. Examples of storage unit 7 include a recovery tank that recovers concentrated gas and a burial site where concentrated gas is buried. However, storage unit 7 is not limited to a recovery tank and a burial site.

[0040] The means for desorbing the carbon dioxide adsorbed in second carbon dioxide adsorbent 537 is not limited to vacuum suction by vacuum pump 581. The means for desorbing the carbon dioxide adsorbed in second carbon dioxide adsorbent 537 may be, for example, a heating device using infrared rays, microwaves, high-frequency induction, or the like. In this case, as described above, the means for sucking the concentrated gas may be a pump other than a vacuum pump or a fan.

[0041] For example, when a predetermined time has elapsed since partition plate 538 started to move in direction A1 shown in Fig. 2, control device 6 changes the setting of three-way valve 523 from the first state to the second state. In other words, when a predetermined time has elapsed since the volume of internal space 532S of second carbon dioxide adsorption tank 532 started to contract, control device 6 changes the setting of three-way valve 523 from the first state to the second state.

[0042] Alternatively, for example, when the partition plate 538 moves in the direction A1 shown in FIG. 2 and reaches a predetermined position inside the second carbon dioxide adsorption tank 532, the control device 6 changes the setting of the three-way valve 523 from the first state to the second state.

[0043] Alternatively, for example, when flow meter 524 (see FIG. 1) measures a predetermined amount of air flowing through second flow path 232, control device 6 changes the setting of three-way valve 523 from the first state to the second state. Flow meter 524 is provided in second flow path 232 and measures the flow rate of air flowing through second flow path 232.

[0044] In this way, before vacuum pump 581 sucks in the concentrated gas, the volume of internal space 532S of second carbon dioxide adsorption tank 532 contracts, thereby discharging a predetermined amount of air present in internal space 532S of second carbon dioxide adsorption tank 532. Then, after the predetermined amount of air present in internal space 532S of second carbon dioxide adsorption tank 532 has been discharged into the atmosphere, vacuum pump 581 sucks in the concentrated gas.

[0045] 3, the first intake valve 511 and the second intake valve 512 are open. In this case, the air guided from the blower 22 to the carbon dioxide capture device 5 is guided to the first carbon dioxide adsorption tank 531 and the second carbon dioxide adsorption tank 532, and passes through the first carbon dioxide adsorption tank 531 and the second carbon dioxide adsorption tank 532. As the air passes through the first carbon dioxide adsorption tank 531 and the second carbon dioxide adsorption tank 532, the carbon dioxide contained in the air is adsorbed by the first carbon dioxide adsorbent 535 accommodated in the first carbon dioxide adsorption tank 531 and the second carbon dioxide adsorption tank 532.

[0046] At this time, the volume of internal space 532S of second carbon dioxide adsorption tank 532 expands. That is, at timing T1 and timing T2, the volume of internal space 532S of second carbon dioxide adsorption tank 532 contracts. Therefore, as the air passes through second carbon dioxide adsorption tank 532, the volume of internal space 532S of second carbon dioxide adsorption tank 532 expands.

[0047] Also, at timing T3, first exhaust valve 521 and second exhaust valve 522 are closed. Therefore, the gas that has had carbon dioxide adsorbed by first carbon dioxide adsorbent 535 and passed through first carbon dioxide adsorption tank 531 passes through first check valve 551 and throttle valve 561 as recovered gas, and is released into the atmosphere. Also, the gas that has had carbon dioxide adsorbed by second carbon dioxide adsorbent 537 and passed through second carbon dioxide adsorption tank 532 passes through second check valve 552 and throttle valve 561 as recovered gas, and is released into the atmosphere.

[0048] 3, first intake valve 511 is closed, and second intake valve 512 is open. In this case, air guided from blower 22 to carbon dioxide capture device 5 is guided to second carbon dioxide adsorption tank 532 and passes through second carbon dioxide adsorption tank 532. As the air passes through second carbon dioxide adsorption tank 532, carbon dioxide contained in the air is adsorbed by second carbon dioxide adsorbent 537 housed in second carbon dioxide adsorption tank 532. At this time, the volume of internal space 532S of second carbon dioxide adsorption tank 532 expands.

[0049] Also, at timing T4, second exhaust valve 522 is closed. Therefore, the gas that has had carbon dioxide adsorbed by second carbon dioxide adsorbent 537 and passed through second carbon dioxide adsorption tank 532 passes through second check valve 552 and throttle valve 561, flows through fourth flow path 234, and is released into the atmosphere as recovered gas.

[0050] Furthermore, at timing T4, the first exhaust valve 521 is open, and the three-way valve 523 is set to the first state.

[0051] In this state, as indicated by arrow A3 in FIG. 2, partition plate 536 (see FIG. 2) of first carbon dioxide adsorption tank 531 moves in direction A1 in FIG. 2. This causes the volume of internal space 531S (see FIG. 2) of first carbon dioxide adsorption tank 531, in which first carbon dioxide adsorbent 535 (see FIG. 2) is accommodated, to contract. As a result, air present in internal space 531S is discharged to the outside of first carbon dioxide adsorption tank 531 in direction A1 in FIG. 2. The air discharged to the outside of first carbon dioxide adsorption tank 531 flows through first flow path 231 and second flow path 232 and is discharged into the atmosphere.

[0052] Next, after a predetermined amount of air present in internal space 531S of first carbon dioxide adsorption tank 531 has been discharged into the atmosphere, vacuum pump 581 is operated at timing T5 shown in Fig. 3. Also, three-way valve 523 is changed from the first state to the second state. Therefore, at timing T5, vacuum pump 581 applies vacuum to first carbon dioxide adsorption tank 531 through filter 571.

[0053] As a result, the carbon dioxide adsorbed to first carbon dioxide adsorbent 535 is desorbed. The gas containing the desorbed carbon dioxide flows as a concentrated gas through first flow path 231 and third flow path 233, and is led to storage section 7. Note that the means for desorbing the carbon dioxide adsorbed to first carbon dioxide adsorbent 535 is not limited to vacuum suction by vacuum pump 581. This is as described above with respect to the means for desorbing the carbon dioxide adsorbed to second carbon dioxide adsorbent 537.

[0054] As described above, for example, the control device 6 changes the setting of the three-way valve 523 from the first state to the second state when a predetermined time has elapsed since the partition plate 538 started to move in the direction A1 shown in Fig. 2. Alternatively, for example, the control device 6 changes the setting of the three-way valve 523 from the first state to the second state when the partition plate 538 moves in the direction A1 shown in Fig. 2 and reaches a predetermined position inside the first carbon dioxide adsorption tank 531. Alternatively, for example, the control device 6 changes the setting of the three-way valve 523 from the first state to the second state when the flow meter 524 measures a predetermined amount of air flowing through the second flow path 232.

[0055] In this way, before vacuum pump 581 sucks in the concentrated gas, the volume of internal space 531S of first carbon dioxide adsorption tank 531 contracts, thereby discharging a predetermined amount of air present in internal space 531S of first carbon dioxide adsorption tank 531. Then, after the predetermined amount of air present in internal space 531S of first carbon dioxide adsorption tank 531 has been discharged into the atmosphere, vacuum pump 581 sucks in the concentrated gas.

[0056] 3 is the same as the operation at timing T3. Then, as described above, when the control at timing T6 is completed, the control at timing T1 is executed again. That is, the controls at timings T1 to T6 are repeatedly executed in this order.

[0057] According to the carbon dioxide capture system 2 of this embodiment, before the vacuum pump 581 draws in the concentrated gas, the volume of the internal space 531S of the first carbon dioxide adsorption tank 531, in which the first carbon dioxide adsorbent 535 is accommodated, first contracts, thereby discharging a predetermined amount of air present in the internal space 531S of the first carbon dioxide adsorption tank 531. Then, after the predetermined amount of air has been discharged from the first carbon dioxide adsorption tank 531, the vacuum pump 581 draws in the concentrated gas. This prevents the vacuum pump 581 from consuming unnecessary power to discharge the air present in the internal space 531S of the first carbon dioxide adsorption tank 531. The same applies to the second carbon dioxide adsorption tank 532. As a result, the carbon dioxide capture system 2 of this embodiment can reduce power consumption when drawing in concentrated gas containing carbon dioxide desorbed from the first carbon dioxide adsorbent 535 and the second carbon dioxide adsorbent 537. In addition, before the vacuum pump 581 sucks in the concentrated gas, the air present in the internal space 531S of the first carbon dioxide adsorption tank 531 and the internal space 532S of the second carbon dioxide adsorption tank 532 is discharged, thereby increasing the concentration of carbon dioxide contained in the concentrated gas sucked in by the vacuum pump 581.

[0058] Furthermore, the three-way valve 523 is set to the first state when a predetermined amount of air present in the internal space 531S of the first carbon dioxide adsorption tank 531 is discharged. The three-way valve 523 is set to the second state when the vacuum pump 581 draws in the concentrated gas after the predetermined amount of air has been discharged. In this manner, the three-way valve 523 can switch between the first state and the second state. Therefore, the carbon dioxide capture system 2 according to this embodiment can more reliably contract the volume of the internal space 531S of the first carbon dioxide adsorption tank 531 by discharging the predetermined amount of air present in the internal space 531S of the first carbon dioxide adsorption tank 531 into the atmosphere through the first flow path 231 and the second flow path 232. Furthermore, after the predetermined amount of air has been discharged, the carbon dioxide adsorbed in the first carbon dioxide adsorbent 535 can be released from the first carbon dioxide adsorbent 535 and drawn by the vacuum pump 581 through the first flow path 231 and the third flow path 233. The same applies to the second carbon dioxide adsorption tank 532. As a result, the carbon dioxide capture system 2 according to this embodiment can more reliably reduce the power consumption when the vacuum pump 581 sucks the concentrated gas.

[0059] Furthermore, the control device 6 changes the setting of the three-way valve 523 from the first state to the second state when a predetermined time has elapsed since the partition plate 536 started to move in the direction A1 shown in FIG. 2 , when the partition plate 536 reaches a predetermined position inside the first carbon dioxide adsorption tank 531, or when the flow meter 524 measures a predetermined amount of air flowing through the second flow path 232. This more reliably discharges the predetermined amount of air present in the internal space 531S of the first carbon dioxide adsorption tank 531 into the atmosphere. Therefore, the carbon dioxide capture system 2 according to this embodiment can more reliably contract the volume of the internal space 531S of the first carbon dioxide adsorption tank 531. The same applies to the second carbon dioxide adsorption tank 532. This more reliably reduces the power consumption when the vacuum pump 581 sucks the concentrated gas.

[0060] Furthermore, the volume of internal space 531S of first carbon dioxide adsorption tank 531, in which first carbon dioxide adsorbent 535 is housed, expands as the air sent in from blower 22 passes through first carbon dioxide adsorption tank 531. The same applies to second carbon dioxide adsorption tank 532. Therefore, as the air sent in from blower 22 passes through first carbon dioxide adsorption tank 531 and second carbon dioxide adsorption tank 532, pressure loss that occurs in internal space 531S of first carbon dioxide adsorption tank 531 and internal space 532S of second carbon dioxide adsorption tank 532 is reduced, and carbon dioxide contained in the air sent in from blower 22 can be efficiently adsorbed by first carbon dioxide adsorbent 535 and second carbon dioxide adsorbent 537.

[0061] Furthermore, first carbon dioxide adsorbent 535 has a structure that allows it to expand and contract in direction A1, in which air present in internal space 531S of first carbon dioxide adsorption tank 531 is discharged, and in direction A2, in which air sent from blower 22 passes through first carbon dioxide adsorption tank 531. Therefore, when the volume of internal space 531S of first carbon dioxide adsorption tank 531, in which first carbon dioxide adsorbent 535 is housed, contracts and expands, first carbon dioxide adsorbent 535 can be prevented from impeding the contraction and expansion of the volume of internal space 531S. The same applies to second carbon dioxide adsorbent 537. As a result, carbon dioxide capture system 2 according to this embodiment can more reliably reduce the power consumption when vacuum pump 581 sucks concentrated gas.

[0062] The above describes the embodiments of the present invention. However, the present invention is not limited to the above embodiments, and various modifications can be made without departing from the scope of the claims. The configurations of the above embodiments can be partially omitted or arbitrarily combined in a different manner from the above. [Explanation of symbols]

[0063] 2: Carbon dioxide capture system, 5: Carbon dioxide capture device, 6: Control device, 7: Storage unit, 21: Filter, 22: Blower, 61: Calculation unit, 62: Memory unit, 231: First flow path, 232: Second flow path, 233: Third flow path, 234: Fourth flow path, 511: First intake valve, 512: Second intake valve, 521: First exhaust valve, 522: Second exhaust valve, 523: Three-way valve, 524: Flow meter, 531: First carbon dioxide adsorption tank, 531S: Internal space, 532: Second carbon dioxide adsorption tank, 532S: Internal space, 535: First carbon dioxide adsorbent, 536: Partition plate, 537: Second carbon dioxide adsorbent, 538: Partition plate, 541: First pressure sensor, 542: Second pressure sensor, 551: First check valve, 552: Second check valve, 561: Throttle valve, 571: Filter, 581: Vacuum pump

Claims

1. A carbon dioxide capture system that captures carbon dioxide directly from the atmosphere, A blower that blows air, a carbon dioxide adsorption tank that accommodates a carbon dioxide adsorbent that adsorbs the carbon dioxide contained in the air sent from the blower; a suction means for suctioning the concentrated gas containing the carbon dioxide desorbed from the carbon dioxide adsorbent and directing the concentrated gas toward a storage section that stores the carbon dioxide; Equipped with A carbon dioxide recovery system characterized in that before the suction means suctions the concentrated gas, a predetermined amount of air present in the internal space is discharged by contracting the volume of the internal space of the carbon dioxide adsorption tank in which the carbon dioxide adsorbent is contained, and after the predetermined amount of air has been discharged, the suction means suctions the concentrated gas.

2. a three-way valve that switches between a first state in which a first flow path connected to the carbon dioxide adsorption tank is connected to a second flow path connected to the atmosphere, and a second state in which the first flow path is connected to a third flow path connected to the suction means, 2. The carbon dioxide recovery system according to claim 1, wherein the three-way valve is set to the first state when the predetermined amount of air present in the internal space is discharged, and is set to the second state when the suction means suctions the concentrated gas after the predetermined amount of air has been discharged.

3. 3. The carbon dioxide recovery system according to claim 2, wherein the three-way valve is changed from the first state to the second state when a predetermined time has elapsed since the contraction of the volume starts.

4. the carbon dioxide adsorption tank has a partition plate that is provided inside the carbon dioxide adsorption tank and is movable in a direction in which the air is discharged, The carbon dioxide capture system described in claim 2, characterized in that the partition plate moves along the direction in which the air is discharged, and when the partition plate reaches a predetermined position inside the carbon dioxide adsorption tank, the three-way valve is changed from the first state to the second state.

5. a flow meter provided in the second flow path and configured to measure a flow rate of the air flowing through the second flow path; 3. The carbon dioxide capture system of claim 2, wherein when the flow meter measures the predetermined amount of air flowing through the second flow path, the three-way valve is changed from the first state to the second state.

6. the carbon dioxide contained in the air sent from the blower is adsorbed by the carbon dioxide adsorbent during the process in which the air sent from the blower is guided to the carbon dioxide adsorption tank and passes through the carbon dioxide adsorption tank; 2. The carbon dioxide recovery system according to claim 1, wherein the volume expands during the process in which the air sent from the blower passes through the carbon dioxide adsorption tank.

7. The carbon dioxide recovery system described in claim 6, characterized in that the carbon dioxide adsorbent has a structure that is expandable and contractible in a direction in which the air present in the internal space is discharged and in a direction in which the air sent from the blower passes through the carbon dioxide adsorption tank.

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