Carbon dioxide recovery system

Abstract

To provide a carbon dioxide recovery system capable of efficiently recovering carbon dioxide directly from the atmosphere and efficiently regenerating a moisture adsorbent.SOLUTION: A carbon dioxide recovery system 2 includes a moisture removal device 3 and a carbon dioxide recovery device 4. Pretreated gas that has passed through one of a first moisture adsorbent and a second moisture adsorbent of the moisture removal device 3 is guided to the carbon dioxide recovery device 4. Concentrated gas containing carbon dioxide separated after being adsorbed by any one of a first carbon dioxide adsorbent and a second carbon dioxide adsorbent of the first carbon dioxide recovery device 4 is guided to a storage unit that stores the carbon dioxide. Recovered gas, which has passed through either the first carbon dioxide adsorbent or the second carbon dioxide adsorbent to recover carbon dioxide, is directed to either the first moisture adsorbent or the second moisture adsorbent.SELECTED DRAWING: Figure 1

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 recovery device that recovers carbon dioxide from exhaust gas emitted from an exhaust gas generation source. Examples of exhaust gas generation sources described in Patent Document 1 include incinerators, coal-fired boilers, LNG-fired boilers, blast furnaces and converters in steel mills, kilns in cement factories, and gas turbines. Furthermore, examples of gases contained in the exhaust gas emitted from the exhaust gas generation sources include nitrogen, oxygen, carbon dioxide, water, and acidic gases.

[0003] The carbon dioxide capture device described in Patent Document 1 uses zeolite as a carbon dioxide adsorbent capable of adsorbing carbon dioxide. Zeolite adsorbs moisture and carbon dioxide. Therefore, when exhaust gas containing moisture and carbon dioxide is passed through zeolite, the zeolite adsorbs the moisture and carbon dioxide in the exhaust gas. This is known to reduce the carbon dioxide adsorption efficiency.

[0004] Therefore, the carbon dioxide capture device described in Patent Document 1 includes a pretreatment device and a carbon dioxide capture device. The pretreatment device has a moisture adsorbent capable of adsorbing moisture and an acidic gas adsorbent capable of adsorbing acidic gases, and removes moisture and acidic gases from the exhaust gas. The carbon dioxide capture device has a carbon dioxide adsorbent capable of adsorbing carbon dioxide, and adsorbs carbon dioxide contained in the pretreated gas that has passed through the moisture adsorbent and the acidic gas adsorbent.

[0005] In the carbon dioxide capture device described in Patent Document 1, the moisture-poor off-gas that has passed through the carbon dioxide capture device is introduced into a pretreatment device, whereby the moisture adsorbent and acid gas adsorbent are regenerated. In the regeneration process of the moisture adsorbent and acid gas adsorbent, moisture is released from the moisture adsorbent, and acid gases are released from the acid gas adsorbent.

[0006] Here, in order to reduce carbon dioxide emissions from the perspective of protecting the global environment, technology for directly capturing carbon dioxide from the atmosphere (Direct Air Capture: DAC) is being studied. The concentration of carbon dioxide contained in the atmosphere is lower than the concentration of carbon dioxide contained in exhaust gas as described in Patent Document 1. Therefore, there is room for improvement in the carbon dioxide capture device described in Patent Document 1 in terms of efficiently capturing carbon dioxide directly from the atmosphere and efficiently regenerating the moisture adsorbent. [Prior art documents] [Patent documents]

[0007] [Patent Document 1] Japanese Patent Application Publication No. 2023-146402 Summary of the Invention [Problem to be solved by the invention]

[0008] The present invention has been made in view of the above circumstances, and has an object to provide a carbon dioxide recovery system that can efficiently recover carbon dioxide directly from the atmosphere and efficiently regenerate a moisture 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 moisture removal device that removes moisture from the atmosphere; and a carbon dioxide capture device that adsorbs the carbon dioxide from pretreated gas that has had the moisture removed by the moisture removal device and has passed through the moisture removal device, wherein the moisture removal device has a first moisture adsorbent that removes the moisture from the atmosphere and a second moisture adsorbent that removes the moisture from the atmosphere, and the carbon dioxide capture device has a first carbon dioxide adsorbent that adsorbs the carbon dioxide from the pretreated gas and a second carbon dioxide adsorbent that adsorbs the carbon dioxide from the pretreated gas. a carbon dioxide capture system having a water adsorbent and a water adsorbent, wherein the pretreated gas that has passed through either the first water adsorbent or the second water adsorbent is introduced to the carbon dioxide capture device, the concentrated gas containing the carbon dioxide that has been adsorbed by either the first carbon dioxide adsorbent or the second carbon dioxide adsorbent and then desorbed is introduced toward a storage section that stores the carbon dioxide, and the captured gas that has passed through the other of the first carbon dioxide adsorbent or the second carbon dioxide adsorbent and has had the carbon dioxide captured is introduced to the other of the first water adsorbent or the second water adsorbent.

[0010] According to one aspect of the present invention, the moisture removal device has a first moisture adsorbent and a second moisture adsorbent and removes moisture from the atmosphere. The pretreated gas from which moisture has been removed by the moisture removal device and which has passed through either the first moisture adsorbent or the second moisture adsorbent is guided to a carbon dioxide capture device. The carbon dioxide capture device has a first carbon dioxide adsorbent and a second carbon dioxide adsorbent and adsorbs carbon dioxide from the pretreated gas. In this way, one aspect of the present invention adsorbs carbon dioxide in the carbon dioxide capture device. This allows one aspect of the present invention to efficiently capture carbon dioxide directly from the atmosphere, where the carbon dioxide concentration is lower than in exhaust gases, etc.

[0011] Furthermore, the captured gas that has passed through the other of the first carbon dioxide adsorbent and the second carbon dioxide adsorbent and from which carbon dioxide has been removed is guided to the other of the first moisture adsorbent and the second moisture adsorbent. The moisture has been removed from the captured gas, and carbon dioxide has been removed. Therefore, the amounts of moisture and carbon dioxide contained in the captured gas are less than those in the atmosphere. One of the features of directly capturing carbon dioxide from the atmosphere is that the captured gas contains a larger amount of air than other exhaust gases. This allows the captured gas that has passed through the other of the first carbon dioxide adsorbent and the second carbon dioxide adsorbent of the carbon dioxide capture device and contains a relatively large amount of air to efficiently remove moisture from the other of the first moisture adsorbent and the second moisture adsorbent, which does not guide the pretreated gas to the carbon dioxide capture device. This allows one aspect of the present invention to efficiently regenerate the first moisture adsorbent and the second moisture adsorbent. [Effects of the Invention]

[0012] According to the present invention, it is possible to provide a carbon dioxide recovery system that can efficiently recover carbon dioxide directly from the atmosphere and efficiently regenerate a moisture adsorbent. [Brief explanation of the drawings]

[0013] [Figure 1] 1 is a system diagram showing a carbon dioxide capture system according to a first embodiment of the present invention. [Figure 2] 1 is a system diagram showing a moisture removal device according to an embodiment of the present invention. [Figure 3] 4 is a timing chart illustrating the operation of the moisture removal device of the present embodiment. [Figure 4] 4 is a timing chart illustrating the operation of the first carbon dioxide recovery device of the present embodiment. [Figure 5] 5 is a timing chart illustrating the operation of the second carbon dioxide recovery device of the present embodiment. [Figure 6] FIG. 4 is a system diagram showing a carbon dioxide capture system according to a second embodiment of the present invention. DETAILED DESCRIPTION OF THE INVENTION

[0014] 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.

[0015] FIG. 1 is a system diagram showing a carbon dioxide capture system according to a first embodiment of the present invention. FIG. 2 is a system diagram showing the moisture removal device of this embodiment. 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 moisture removal device 3, a first carbon dioxide capture device 4, a second carbon dioxide capture device 5, and a control device 6. The number of carbon dioxide capture devices installed may be one, or three or more.

[0016] The moisture removal device 3 is a device that removes moisture from the atmosphere, which is a component that reduces the carbon dioxide adsorption efficiency in the first carbon dioxide capture device 4 and the second carbon dioxide capture device 5. The first carbon dioxide capture device 4 is provided downstream of the moisture removal device 3 and is a device that adsorbs carbon dioxide from the pretreated gas that has had moisture removed by the moisture removal device 3 and has passed through the moisture removal device 3. The second carbon dioxide capture device 5 is provided downstream of the first carbon dioxide capture device 4 and is a device that further adsorbs carbon dioxide from the concentrated gas that contains carbon dioxide that has been desorbed after being adsorbed by the first carbon dioxide capture device 4. In this way, the carbon dioxide capture system 2 according to this embodiment adsorbs carbon dioxide contained in the pretreated gas that has had moisture removed by the moisture removal device 3 in two stages, in the first carbon dioxide capture device 4 and the second carbon dioxide capture device.

[0017] As shown in FIG. 2, the moisture removal device 3 includes a first adsorption valve 311, a second adsorption valve 312, a first exhaust valve 321, a second exhaust valve 322, a first moisture adsorption tank 331, a second moisture adsorption tank 332, a first pressure sensor 341, a second pressure sensor 342, a first inlet valve 351, a second inlet valve 352, a first outlet valve 361, a second outlet valve 362, and a flow meter 371.

[0018] The first moisture adsorption tank 331 contains a first moisture adsorbent. The first moisture adsorbent is, for example, zeolite, and removes moisture from the atmosphere. The second moisture adsorption tank 332 contains a second moisture adsorbent. The second moisture adsorbent is, for example, zeolite, and removes moisture from the atmosphere.

[0019] The first pressure sensor 341 detects the pressure inside the first moisture adsorption tank 331 and sends a signal related to the pressure inside the first moisture adsorption tank 331 to the control device 6. The second pressure sensor 342 detects the pressure inside the second moisture adsorption tank 332 and sends a signal related to the pressure inside the second moisture adsorption tank 332 to the control device 6.

[0020] As shown in FIG. 1, the first carbon dioxide recovery device 4 includes a first adsorption valve 411, a second adsorption valve 412, a first exhaust valve 421, a second exhaust valve 422, a first carbon dioxide adsorption tank 431, a second carbon dioxide adsorption tank 432, a first buffer tank 433, a first pressure sensor 441, a second pressure sensor 442, a third pressure sensor 443, a first check valve 451, a second check valve 452, a third check valve 453, a first throttle valve 461, a second throttle valve 462, a first filter 471, a first vacuum pump 481, a first boost pump 482, and a first exhaust valve 491.

[0021] The first carbon dioxide adsorption tank 431 contains a first carbon dioxide adsorbent. The first carbon dioxide adsorbent is, for example, zeolite, and adsorbs carbon dioxide from the pretreated gas that has had moisture removed by the moisture removal device 3 and has passed through the moisture removal device 3. The second carbon dioxide adsorption tank 432 contains a second carbon dioxide adsorbent. The second carbon dioxide adsorbent is, for example, zeolite, and adsorbs carbon dioxide from the pretreated gas that has had moisture removed by the moisture removal device 3 and has passed through the moisture removal device 3.

[0022] The first pressure sensor 441 detects the pressure inside the first carbon dioxide adsorption tank 431 and sends a signal related to the pressure inside the first carbon dioxide adsorption tank 431 to the control device 6. The second pressure sensor 442 detects the pressure inside the second carbon dioxide adsorption tank 432 and sends a signal related to the pressure inside the second carbon dioxide adsorption tank 432 to the control device 6. The third pressure sensor 443 detects the pressure inside the first buffer tank 433 and sends a signal related to the pressure inside the first buffer tank 433 to the control device 6.

[0023] As shown in FIG. 1, the second carbon dioxide capture device 5 includes a third adsorption valve 511, a fourth adsorption valve 512, a third exhaust valve 521, a fourth exhaust valve 522, a third carbon dioxide adsorption tank 531, a fourth carbon dioxide adsorption tank 532, a second buffer tank 533, a fourth pressure sensor 541, a fifth pressure sensor 542, a sixth pressure sensor 543, a fourth check valve 551, a fifth check valve 552, a sixth check valve 553, a third throttle valve 561, a second filter 571, a third filter 572, a second vacuum pump 581, a second boost pump 582, a second exhaust valve 591, a pressure reducing valve 592, a flow meter 593, and a constant flow valve 594.

[0024] The third carbon dioxide adsorption tank 531 contains a third carbon dioxide adsorbent. The third carbon dioxide adsorbent is, for example, zeolite, and further adsorbs carbon dioxide from the concentrated gas containing carbon dioxide that has been desorbed after being adsorbed by the first carbon dioxide capture unit 4. The fourth carbon dioxide adsorption tank 532 contains a fourth carbon dioxide adsorbent. The fourth carbon dioxide adsorbent is, for example, zeolite, and further adsorbs carbon dioxide from the concentrated gas containing carbon dioxide that has been adsorbed by the first carbon dioxide capture unit 4 and then desorbed.

[0025] The fourth pressure sensor 541 detects the pressure inside the third carbon dioxide adsorption tank 531 and sends a signal related to the pressure inside the third carbon dioxide adsorption tank 531 to the control device 6. The fifth pressure sensor 542 detects the pressure inside the fourth carbon dioxide adsorption tank 532 and sends a signal related to the pressure inside the fourth carbon dioxide adsorption tank 532 to the control device 6. The sixth pressure sensor 543 detects the pressure inside the second buffer tank 533 and sends a signal related to the pressure inside the second buffer tank 533 to the control device 6.

[0026] As shown in Figure 1, the control device 6 has a calculation unit 61 and a memory unit 62, and sends signals to each valve provided in the moisture removal device 3, the first carbon dioxide capture device 4 and the second carbon dioxide capture device 5 to control the operation of each valve, and receives signals from each sensor provided in the moisture removal device 3, the first carbon dioxide capture device 4 and the second carbon dioxide capture device 5.

[0027] The calculation unit 61 is, for example, a CPU (Central Processing Unit) and performs program startup, signal control processing, calculations, drive control of a display unit (not shown), etc. based on signals (commands) sent from an operation unit (not shown). In other words, the calculation unit 61 controls the entire carbon dioxide capture system 2.

[0028] The storage unit 62 stores a sequence program for executing control to remove moisture from the atmosphere in the moisture removal device 3, a sequence program for executing control to adsorb carbon dioxide from the pretreated gas in the first carbon dioxide recovery device 4, a sequence program for executing control to further adsorb carbon dioxide from the concentrated gas in the second carbon dioxide recovery device 5, and a program for integrating and managing these sequence programs. The storage unit 62 also stores various data such as measurement data.

[0029] The storage unit 62 may be, for example, a semiconductor memory provided in the carbon dioxide capture system 2. Alternatively, the storage unit 62 may be any of various storage media 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 HDD (Hard Disk Drive), an SSD (Solid State Drive), or a memory card.

[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 moisture removal device of this embodiment. FIG. 4 is a timing chart illustrating the operation of the first carbon dioxide recovery device of this embodiment. FIG. 5 is a timing chart illustrating the operation of the second carbon dioxide recovery unit of this embodiment.

[0031] Note that the hatching in the timing charts of Figures 3 to 5 indicates that each valve is open at each timing (T31 to T32, T41 to T46, T51 to T56), and that each pump is operating at each timing (T31 to T32, T41 to T46, T51 to T56).

[0032] The timings T31 to T32 are arranged in chronological order. When the control at timing T32 is completed, the control at timing T31 is executed again. In other words, the control at timings T31 to T32 is repeatedly executed in this order. The timings T41 to T46 are arranged in chronological order. When the control at timing T46 is completed, the control at timing T41 is executed again. In other words, the control at timings T41 to T46 is repeatedly executed in this order. Timings T51 to T56 are arranged in chronological order. When the control at timing T56 is completed, the control at timing T51 is executed again. In other words, the controls at timings T51 to T56 are repeatedly executed in this order.

[0033] 1 and 2, air pump 22 sucks in atmospheric air (i.e., air) through filter 21 and sends the sucked air to moisture removal device 3. As shown in Fig. 4, air pump 22 is constantly operating from timings T41 to T46. The air sucked in by air pump 22 contains moisture and carbon dioxide.

[0034] As shown in FIG. 2, air sent from air pump 22 to moisture removal device 3 is guided to at least one of first moisture adsorption tank 331 and second moisture adsorption tank 332 depending on the timing of control.

[0035] 3, the first adsorption valve 311 is open, and the second adsorption valve 312 is closed. In this case, the air sent from the air pump 22 to the moisture removal device 3 is guided to the first moisture adsorption tank 331 and passes through the first moisture adsorption tank 331. As the air passes through the first moisture adsorption tank 331, the moisture contained in the air is adsorbed by the first moisture adsorbent contained in the first moisture adsorption tank 331.

[0036] Furthermore, at timing T31, the first outlet valve 361 is open, and the first exhaust valve 321, the first inlet valve 351, and the second outlet valve 362 are closed. Therefore, the gas that has had moisture adsorbed by the first moisture adsorbent and passed through the first moisture adsorption tank 331 passes through the flow meter 371 as pretreated gas and is guided to the first carbon dioxide capture device 4. The duration of timing T31 is, for example, approximately 60 seconds.

[0037] 3, the first adsorption valve 311 is closed and the second adsorption valve 312 is open. In this case, the air sent from the air pump 22 to the moisture removal device 3 is guided to the second moisture adsorption tank 332 and passes through the second moisture adsorption tank 332. As the air passes through the second moisture adsorption tank 332, the moisture contained in the air is adsorbed by the second moisture adsorbent contained in the second moisture adsorption tank 332.

[0038] Furthermore, at timing T32, second outlet valve 362 is open, and second exhaust valve 322, second inlet valve 352, and first outlet valve 361 are closed. Therefore, the gas that has had moisture adsorbed by the second moisture adsorbent and passed through second moisture adsorption tank 332 passes through flow meter 371 as pretreated gas and is guided to first carbon dioxide capture device 4. The duration of timing T32 is, for example, approximately 60 seconds.

[0039] As shown in FIG. 1, the pretreated gas guided from the moisture removal device 3 to the first carbon dioxide recovery device 4 is guided to at least one of the first carbon dioxide adsorption tank 431 and the second carbon dioxide adsorption tank 432 depending on the timing of control.

[0040] 4, the first adsorption valve 411 is open, and the second adsorption valve 412 is closed. In this case, the pretreated gas guided from the moisture removal device 3 to the first carbon dioxide recovery device 4 is guided to the first carbon dioxide adsorption tank 431 and passes through the first carbon dioxide adsorption tank 431. As the pretreated gas passes through the first carbon dioxide adsorption tank 431, the carbon dioxide contained in the pretreated gas is adsorbed by the first carbon dioxide adsorbent accommodated in the first carbon dioxide adsorption tank 431.

[0041] At timing T41, the first exhaust valve 421 is closed. Therefore, the gas that has had carbon dioxide adsorbed by the first carbon dioxide adsorbent and passed through the first carbon dioxide adsorption tank 431 passes through the first check valve 451 and the first throttle valve 461 as the first recovered gas, and is guided to the moisture removal device 3.

[0042] Furthermore, at timing T41, the second exhaust valve 422 is open, and the first vacuum pump 481 and the first boost pump 482 are operating. As shown in FIG. 4, the first vacuum pump 481 and the first boost pump 482 are always operating from timing T41 to timing T46. Therefore, the second carbon dioxide adsorption tank 432 is vacuum-suctioned by the first vacuum pump 481 through the first filter 471. As a result, the carbon dioxide adsorbed to the second carbon dioxide adsorbent is desorbed. The desorbed gas containing carbon dioxide is guided toward the storage unit 7 as a first concentrated gas. Specifically, the desorbed gas containing carbon dioxide is sent from the first boost pump 482 toward the first exhaust valve 491 as the first concentrated gas.

[0043] At timing T41, the first exhaust valve 491 is closed. Therefore, the first concentrated gas sent from the first boost pump 482 does not pass through the first exhaust valve 491. The duration of timing T41 is, for example, approximately 60 seconds.

[0044] 4, the first adsorption valve 411 and the second adsorption valve 412 are open. In this case, the pretreated gas guided from the moisture removal device 3 to the first carbon dioxide recovery device 4 is guided to the first carbon dioxide adsorption tank 431 and the second carbon dioxide adsorption tank 432, and passes through the first carbon dioxide adsorption tank 431 and the second carbon dioxide adsorption tank 432. As the pretreated gas passes through the first carbon dioxide adsorption tank 431 and the second carbon dioxide adsorption tank 432, the carbon dioxide contained in the pretreated gas is adsorbed by the first carbon dioxide adsorbent accommodated in the first carbon dioxide adsorption tank 431 and the first carbon dioxide adsorbent accommodated in the second carbon dioxide adsorption tank 432.

[0045] Also, at timing T42, the first exhaust valve 421 and the second exhaust valve 422 are closed. Therefore, the gas that has had carbon dioxide adsorbed by the first carbon dioxide adsorbent and passed through the first carbon dioxide adsorption tank 431 passes through the first check valve 451 and the first throttle valve 461 as the first recovered gas, and is guided to the moisture removal device 3. Also, the gas that has had carbon dioxide adsorbed by the second carbon dioxide adsorbent and passed through the second carbon dioxide adsorption tank 432 passes through the second check valve 452 and the first throttle valve 461 as the first recovered gas, and is guided to the moisture removal device 3. At timing T42, the first exhaust valve 491 is closed. The duration of timing T42 is, for example, approximately 2 seconds.

[0046] 4, the first adsorption valve 411 is closed, and the second adsorption valve 412 is open. In this case, the pretreated gas guided from the moisture removal device 3 to the first carbon dioxide recovery device 4 is guided to the second carbon dioxide adsorption tank 432, and passes through the second carbon dioxide adsorption tank 432. As the pretreated gas passes through the second carbon dioxide adsorption tank 432, the carbon dioxide contained in the pretreated gas is adsorbed by the first carbon dioxide adsorbent accommodated in the second carbon dioxide adsorption tank 432.

[0047] At timing T43, the second exhaust valve 422 is closed. Therefore, the gas that has had carbon dioxide adsorbed by the second carbon dioxide adsorbent and passed through the second carbon dioxide adsorption tank 432 passes through the second check valve 452 and the first throttle valve 461 as the first recovered gas, and is guided to the moisture removal device 3.

[0048] Furthermore, at timing T43, the first exhaust valve 421 is open, and the first vacuum pump 481 and the first boost pump 482 are operating. Therefore, the first carbon dioxide adsorption tank 431 is vacuum-suctioned by the first vacuum pump 481 through the first filter 471. As a result, the carbon dioxide adsorbed to the first carbon dioxide adsorbent is desorbed. The gas containing the desorbed carbon dioxide is guided as a first concentrated gas toward the storage unit 7. Specifically, the gas containing the desorbed carbon dioxide is sent as the first concentrated gas from the first boost pump 482 toward the first exhaust valve 491.

[0049] At timing T43, first discharge valve 491 is open. Therefore, the first concentrated gas sent from first booster pump 482 passes through first discharge valve 491 and third check valve 453, and is guided to first buffer tank 433. The duration of timing T43 is, for example, approximately 2 seconds.

[0050] 4, the first exhaust valve 491 is closed. Therefore, the first concentrated gas sent from the first boost pump 482 does not pass through the first exhaust valve 491. Other operations are the same as those described above for the timing T43. The duration of the timing T44 is, for example, approximately 60 seconds.

[0051] 4, the operation at timing T45 is the same as that at timing T42 described above. The duration of timing T45 is, for example, approximately 2 seconds.

[0052] 4, the first adsorption valve 411 is open and the second adsorption valve 412 is closed. The first exhaust valve 421 is closed and the second exhaust valve 422 is open. Furthermore, the first exhaust valve 491 is open at time T46. Therefore, the first concentrated gas sent from the first booster pump 482 passes through the first exhaust valve 491 and the third check valve 453 and is guided to the first buffer tank 433. Other operations are the same as those described above with respect to time T41. The duration of time T46 is, for example, approximately 2 seconds.

[0053] Subsequently, as described above, when the control at timing T46 is completed, the control at timing T41 is executed again. That is, the controls at timings T41 to T46 are repeatedly executed in this order.

[0054] 4, the first recovered gas guided from the first carbon dioxide capture device 4 to the moisture removal device 3 has moisture removed and carbon dioxide recovered. Therefore, the amounts of moisture and carbon dioxide contained in the first recovered gas are less than the amounts of moisture and carbon dioxide in the air sucked in by the air pump 22. The first recovered gas guided from the first carbon dioxide capture device 4 to the moisture removal device 3 is guided to at least one of the first moisture adsorption tank 331 and the second moisture adsorption tank 332, depending on the timing of control.

[0055] 3, the second inlet valve 352 and the second exhaust valve 322 are open. In this case, the first recovered gas guided from the first carbon dioxide capture device 4 to the moisture removal device 3 is guided to the second moisture adsorption tank 332 and passes through the second moisture adsorption tank 332. As the first recovered gas passes through the second moisture adsorption tank 332, the moisture adsorbed to the second moisture adsorbent is released. The gas containing the released moisture passes through the second exhaust valve 322 and is released into the atmosphere. This regenerates the second moisture adsorbent contained in the second moisture adsorption tank 332.

[0056] That is, at timing T31, the moisture contained in the air sent from the air pump 22 to the moisture removal device 3 is adsorbed by the first moisture adsorbent in the first moisture adsorption tank 331, while the moisture adsorbed by the second moisture adsorbent in the second moisture adsorption tank 332 is released by the first recovered gas led from the first carbon dioxide recovery device 4 to the moisture removal device 3.

[0057] Subsequently, at timing T32, the first inlet valve 351 and the first exhaust valve 321 are opened. In this case, the first recovered gas guided from the first carbon dioxide capture device 4 to the moisture removal device 3 is guided to the first moisture adsorption tank 331 and passes through the first moisture adsorption tank 331. As the first recovered gas passes through the first moisture adsorption tank 331, the moisture adsorbed to the first moisture adsorbent is released. The gas containing the released moisture passes through the first exhaust valve 321 and is released into the atmosphere. This regenerates the first moisture adsorbent contained in the first moisture adsorption tank 331.

[0058] That is, at timing T32, the moisture contained in the air sent from the air pump 22 to the moisture removal device 3 is adsorbed by the second moisture adsorbent in the second moisture adsorption tank 332, while the moisture adsorbed by the first moisture adsorbent in the first moisture adsorption tank 331 is released by the first recovered gas led from the first carbon dioxide recovery device 4 to the moisture removal device 3.

[0059] 4, the first concentrated gas that has passed through the first discharge valve 491 and the third check valve 453 and been guided to the first buffer tank 433 is temporarily stored in the first buffer tank 433, and then passes through the second throttle valve 462 and is guided to the second carbon dioxide capture device 5. As shown in FIG. 1, the first concentrated gas that has been guided from the first carbon dioxide capture device 4 to the second carbon dioxide capture device 5 is guided to at least one of the third carbon dioxide adsorption tank 531 and the fourth carbon dioxide adsorption tank 532, depending on the timing of control.

[0060] 5, the third adsorption valve 511 is open, and the fourth adsorption valve 512 is closed. In this case, the first concentrated gas guided from the first carbon dioxide capture device 4 to the second carbon dioxide capture device 5 is guided to the third carbon dioxide adsorption tank 531 and passes through the third carbon dioxide adsorption tank 531. As the first concentrated gas passes through the third carbon dioxide adsorption tank 531, the carbon dioxide contained in the first concentrated gas is further adsorbed by the third carbon dioxide adsorbent accommodated in the third carbon dioxide adsorption tank 531.

[0061] Also, at timing T51, third exhaust valve 521 is closed. Therefore, the gas that has had carbon dioxide adsorbed by the third carbon dioxide adsorbent and passed through third carbon dioxide adsorption tank 531 passes through fourth check valve 551 and third throttle valve 561 as second recovered gas, and is released into the atmosphere.

[0062] Furthermore, at timing T51, the fourth exhaust valve 522 is open, and the second vacuum pump 581 and the second boost pump 582 are operating. As shown in FIG. 5, the second vacuum pump 581 and the second boost pump 582 are always operating from timing T51 to T56. Therefore, the fourth carbon dioxide adsorption tank 532 is vacuum-suctioned by the second vacuum pump 581 through the second filter 571. As a result, the carbon dioxide adsorbed to the fourth carbon dioxide adsorbent is desorbed. The desorbed gas containing carbon dioxide is guided toward the reservoir 7 as a second concentrated gas. Specifically, the desorbed gas containing carbon dioxide is sent from the second boost pump 582 toward the second exhaust valve 591 as a second concentrated gas.

[0063] At timing T51, second exhaust valve 591 is closed. Therefore, the second concentrated gas sent from second boost pump 582 does not pass through second exhaust valve 591. The duration of timing T51 is, for example, approximately 125 seconds.

[0064] 5 , the third adsorption valve 511 and the fourth adsorption valve 512 are opened. In this case, the first concentrated gas guided from the first carbon dioxide capture device 4 to the second carbon dioxide capture device 5 is guided to the third carbon dioxide adsorption tank 531 and the fourth carbon dioxide adsorption tank 532, and passes through the third carbon dioxide adsorption tank 531 and the fourth carbon dioxide adsorption tank 532. As the first concentrated gas passes through the third carbon dioxide adsorption tank 531 and the fourth carbon dioxide adsorption tank 532, the carbon dioxide contained in the first concentrated gas is adsorbed by the third carbon dioxide adsorbent accommodated in the third carbon dioxide adsorption tank 531 and the fourth carbon dioxide adsorption tank 532.

[0065] Also, at timing T52, third exhaust valve 521 and fourth exhaust valve 522 are closed. Therefore, the gas that has had carbon dioxide adsorbed by the third carbon dioxide adsorbent and passed through third carbon dioxide adsorption tank 531 passes through fourth check valve 551 and third throttle valve 561 as the second recovered gas and is released into the atmosphere. Also, the gas that has had carbon dioxide adsorbed by the fourth carbon dioxide adsorbent and passed through fourth carbon dioxide adsorption tank 532 passes through fifth check valve 552 and third throttle valve 561 as the second recovered gas and is released into the atmosphere. At timing T52, second exhaust valve 591 is closed. The duration of timing T52 is, for example, approximately 2 seconds.

[0066] 5 , the third adsorption valve 511 is closed, and the fourth adsorption valve 512 is open. In this case, the first concentrated gas guided from the first carbon dioxide capture device 4 to the second carbon dioxide capture device 5 is guided to the fourth carbon dioxide adsorption tank 532 and passes through the fourth carbon dioxide adsorption tank 532. As the first concentrated gas passes through the fourth carbon dioxide adsorption tank 532, the carbon dioxide contained in the first concentrated gas is adsorbed by the fourth carbon dioxide adsorbent accommodated in the fourth carbon dioxide adsorption tank 532.

[0067] Furthermore, at timing T53, fourth exhaust valve 522 is closed. Therefore, the gas that has had carbon dioxide adsorbed by the fourth carbon dioxide adsorbent and passed through fourth carbon dioxide adsorption tank 532 passes through fifth check valve 552 and third throttle valve 561 as second recovered gas, and is released into the atmosphere.

[0068] Furthermore, at timing T53, the third exhaust valve 521 is open, and the second vacuum pump 581 and the second boost pump 582 are operating. Therefore, the third carbon dioxide adsorption tank 531 is vacuum-suctioned by the second vacuum pump 581 through the second filter 571. As a result, the carbon dioxide adsorbed to the third carbon dioxide adsorbent is desorbed. The gas containing the desorbed carbon dioxide is guided as the second concentrated gas toward the storage unit 7. Specifically, the gas containing the desorbed carbon dioxide is sent as the second concentrated gas from the second boost pump 582 toward the second exhaust valve 591.

[0069] At timing T53, second discharge valve 591 is open. Therefore, the second concentrated gas sent from second booster pump 582 passes through second discharge valve 591, sixth check valve 553, third filter 572, pressure reducing valve 592, flow meter 593, and constant flow valve 594, and is guided to storage unit 7. Examples of storage unit 7 include a recovery tank that recovers the second concentrated gas and a burial site where the second concentrated gas is buried. However, storage unit 7 is not limited to a recovery tank and a burial site. The duration of timing T53 is, for example, approximately 2 seconds.

[0070] 5, the second exhaust valve 591 is closed. Therefore, the second concentrated gas sent from the second boost pump 582 does not pass through the second exhaust valve 591. The other operations are the same as those described above for the timing T53. The duration of the timing T54 is, for example, approximately 125 seconds.

[0071] 5, the operation at timing T55 is the same as that at timing T52 described above. The duration of timing T55 is, for example, approximately 2 seconds.

[0072] 5, the third adsorption valve 511 is open and the fourth adsorption valve 512 is closed. The third exhaust valve 521 is closed and the fourth exhaust valve 522 is open. Furthermore, the second exhaust valve 591 is open at time T56. Therefore, the second concentrated gas sent from the second booster pump 582 passes through the second exhaust valve 591, the sixth check valve 553, the third filter 572, the pressure reducing valve 592, the flow meter 593, and the constant flow valve 594, and is guided to the reservoir 7. The other operations are the same as those described above with respect to time T51. The duration of time T56 is, for example, approximately 2 seconds.

[0073] Subsequently, as described above, when the control at timing T56 is completed, the control at timing T51 is executed again. That is, the controls at timings T51 to T56 are repeatedly executed in this order.

[0074] As described above, in the carbon dioxide capture system 2 according to this embodiment, the moisture removal device 3 has a first moisture adsorption tank 331 containing a first moisture adsorbent and a second moisture adsorption tank 332 containing a second moisture adsorbent, and removes moisture from the atmosphere. The pretreated gas from which moisture has been removed by the moisture removal device 3 and which has passed through either the first moisture adsorbent or the second moisture adsorbent is guided to the first carbon dioxide capture device 4.

[0075] The first carbon dioxide capture device 4 has a first carbon dioxide adsorption tank 431 that contains a first carbon dioxide adsorbent and a second carbon dioxide adsorption tank 432 that contains a second carbon dioxide adsorbent, and adsorbs carbon dioxide from the pretreated gas. The second carbon dioxide capture device 5 has a third carbon dioxide adsorption tank 531 that contains a third carbon dioxide adsorbent and a fourth carbon dioxide adsorption tank 532 that contains a fourth carbon dioxide adsorbent, and further adsorbs carbon dioxide from the first concentrated gas that contains carbon dioxide that has been adsorbed by the first carbon dioxide capture device 4 and then desorbed from either the first carbon dioxide adsorbent or the second carbon dioxide adsorbent.

[0076] In this way, the carbon dioxide capture system 2 according to this embodiment adsorbs carbon dioxide in two stages, the first carbon dioxide capture device 4 and the second carbon dioxide capture device 5. As a result, the carbon dioxide capture system 2 according to this embodiment can efficiently capture carbon dioxide directly from the atmosphere, where the carbon dioxide concentration is lower than that of exhaust gases, etc.

[0077] The first recovered gas, which has passed through the other of the first carbon dioxide adsorbent and the second carbon dioxide adsorbent and from which carbon dioxide has been removed, is guided to the other of the first moisture adsorbent and the second moisture adsorbent. The first recovered gas has had moisture removed and carbon dioxide removed. Therefore, the amounts of moisture and carbon dioxide contained in the first recovered gas are less than those in the atmosphere. One of the features of directly capturing carbon dioxide from the atmosphere is that the air content of the recovered gas is greater than that of other exhaust gases. This allows the first recovered gas, which has a relatively large air content and has passed through the other of the first carbon dioxide adsorbent and the second carbon dioxide adsorbent in the first-stage first carbon dioxide capture device 4, to efficiently remove moisture from the other of the first moisture adsorbent and the second moisture adsorbent, which is not guided to the first carbon dioxide capture device 4 as pretreated gas. This allows the carbon dioxide capture system 2 according to this embodiment to efficiently regenerate the first moisture adsorbent and the second moisture adsorbent.

[0078] 3, a state in which pretreated gas that has passed through either the first moisture adsorbent or the second moisture adsorbent is introduced to the first carbon dioxide capture device 4 and a state in which pretreated gas that has passed through the other of the first moisture adsorbent or the second moisture adsorbent are introduced to the first carbon dioxide capture device 4 are alternately switched over every predetermined time (approximately 60 seconds in this embodiment). Also, a state in which the first recovered gas is introduced to the other of the first moisture adsorbent or the second moisture adsorbent and a state in which the first recovered gas is introduced to either the first moisture adsorbent or the second moisture adsorbent are alternately switched over every predetermined time (approximately 60 seconds in this embodiment). As a result, the carbon dioxide capture system 2 according to this embodiment can efficiently regenerate both the first moisture adsorbent and the second moisture adsorbent through simple control.

[0079] Furthermore, the second carbon dioxide capture device 5 has a third carbon dioxide adsorption tank 531 that contains a third carbon dioxide adsorbent, and a fourth carbon dioxide adsorption tank 532 that contains a fourth carbon dioxide adsorbent, and further adsorbs carbon dioxide from the first concentrated gas. The second concentrated gas, which contains carbon dioxide that has been adsorbed by either the third carbon dioxide adsorbent or the fourth carbon dioxide adsorbent and then desorbed, is led to a storage section 7 that stores carbon dioxide. In contrast, the second recovered gas, which has passed through the other of the third carbon dioxide adsorbent or the fourth carbon dioxide adsorbent and from which carbon dioxide has been captured, is released into the atmosphere.

[0080] In this way, the second recovered gas that has passed through the other of the third carbon dioxide adsorbent and the fourth carbon dioxide adsorbent in the second-stage second carbon dioxide capture device 5 is not used to regenerate the first moisture adsorbent and the second moisture adsorbent, but is released into the atmosphere. This makes it possible to simplify the carbon dioxide capture system 2 according to this embodiment.

[0081] Next, a second embodiment of the present invention will be described. In addition, in cases where the components of the carbon dioxide capture system 2A according to the second embodiment are similar to the components of the carbon dioxide capture system 2 according to the first embodiment described above with reference to Figures 1 to 5, duplicate explanations will be omitted as appropriate, and the following explanation will focus on the differences.

[0082] FIG. 6 is a system diagram showing a carbon dioxide capture system according to a second embodiment of the present invention. In the carbon dioxide capture system 2 according to the first embodiment, the gas that has had carbon dioxide adsorbed by the third carbon dioxide adsorbent and passed through the third carbon dioxide adsorption tank 531 passes through the fourth check valve 551 and the third throttle valve 561 as the second captured gas, and is then released into the atmosphere. Also, the gas that has had carbon dioxide adsorbed by the fourth carbon dioxide adsorbent and passed through the fourth carbon dioxide adsorption tank 532 passes through the fifth check valve 552 and the third throttle valve 561 as the second captured gas, and is then released into the atmosphere.

[0083] In contrast, in carbon dioxide capture system 2A according to the present embodiment, the gas that has had carbon dioxide adsorbed by the third carbon dioxide adsorbent and passed through third carbon dioxide adsorption tank 531 passes through fourth check valve 551 and third throttle valve 561 as the second recovered gas, and is led to moisture removal device 3. Also, the gas that has had carbon dioxide adsorbed by the fourth carbon dioxide adsorbent and passed through fourth carbon dioxide adsorption tank 532 passes through fifth check valve 552 and third throttle valve 561 as the second recovered gas, and is led to moisture removal device 3.

[0084] The second recovered gas guided from the second carbon dioxide capture device 5 to the moisture removal device 3 has had moisture removed and carbon dioxide removed. Therefore, the amounts of moisture and carbon dioxide contained in the second recovered gas are less than the amounts of moisture and carbon dioxide in the air sucked in by the air pump 22. The second recovered gas guided from the second carbon dioxide capture device 5 to the moisture removal device 3 is guided to at least one of the first moisture adsorption tank 331 and the second moisture adsorption tank 332, depending on the timing of control.

[0085] After the second recovered gas is introduced into the moisture removal device 3, the operation of regenerating the first moisture adsorbent contained in the first moisture adsorption tank 331 and the operation of regenerating the second moisture adsorbent contained in the second moisture adsorption tank 332 are the same as those described above for the carbon dioxide capture system 2 according to the first embodiment. The other configurations and operations are the same as those described above for the carbon dioxide capture system 2 according to the first embodiment.

[0086] In the carbon dioxide capture system 2A according to this embodiment, the second captured gas, which has passed through the other of the third carbon dioxide adsorbent housed in the third carbon dioxide adsorption tank 531 or the fourth carbon dioxide adsorbent housed in the fourth carbon dioxide adsorption tank 532 and from which carbon dioxide has been captured, is further introduced to the other of the first moisture adsorbent or the second moisture adsorbent, in addition to the first captured gas introduced from the first carbon dioxide capture device 4. The second captured gas has had moisture removed and carbon dioxide captured. Therefore, the amounts of moisture and carbon dioxide contained in the second captured gas are less than the amounts of moisture and carbon dioxide in the atmosphere, respectively.

[0087] As a result, the first recovered gas that has passed through the other of the first carbon dioxide adsorbent and the second carbon dioxide adsorbent in the first-stage first carbon dioxide capture device 4, and the second recovered gas that has passed through the other of the third carbon dioxide adsorbent and the fourth carbon dioxide adsorbent in the second-stage second carbon dioxide capture device 5, more efficiently removes moisture from the other of the first moisture adsorbent and the second moisture adsorbent that does not guide the pretreated gas to the first carbon dioxide capture device 4. As a result, the carbon dioxide capture system 2A according to this embodiment can more efficiently regenerate the first moisture adsorbent and the second moisture adsorbent. In addition, the same effects as those of the carbon dioxide capture system 2 according to the first embodiment described above with reference to FIGS. 1 to 5 can be obtained.

[0088] 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]

[0089] 2: Carbon dioxide capture system, 2A: Carbon dioxide capture system, 3: Moisture removal device, 4: First carbon dioxide capture device, 5: Second carbon dioxide capture device, 6: Control device, 7: Storage unit, 21: Filter, 22: Air pump, 61: Calculation unit, 62: Memory unit, 311: First adsorption valve, 312: Second adsorption valve, 321: First exhaust valve, 322: Second exhaust valve, 331: First moisture adsorption tank, 332: Second moisture adsorption tank, 341: First pressure sensor, 342: Second pressure sensor, 351: First inlet valve, 352: Second inlet valve, 361: First outlet valve, 362: Second outlet valve, 371: Flow meter, 411: First adsorption valve, 412: Second adsorption valve, 421: First exhaust valve, 422: Second exhaust valve, 431: First carbon dioxide adsorption tank, 432: Second carbon dioxide adsorption tank, 433: First buffer tank, 441: First pressure sensor, 442: Second pressure sensor, 443: Third pressure sensor, 451: First check valve, 452: Second check valve, 453: Third check valve, 461: First throttle valve, 462: Second throttle valve, 471: First filter, 481: First vacuum pump, 482: First booster pump, 491: First discharge valve, 511: Third adsorption valve, 512: Fourth adsorption valve, 521: Third exhaust valve, 522: Fourth exhaust valve, 531: Third carbon dioxide adsorption tank, 532: Fourth carbon dioxide adsorption tank, 533: Second buffer tank, 541: Fourth pressure sensor, 542: Fifth pressure sensor, 543: Sixth pressure sensor, 551: Fourth check valve, 552: Fifth check valve, 553: Sixth check valve, 561: Third throttle valve, 571: Second filter, 572: Third filter, 581: Second vacuum pump, 582: Second booster pump, 591: Second discharge valve, 592: Pressure reducing valve, 593: Flow meter, 594: Constant flow valve

Claims

1. A carbon dioxide capture system that captures carbon dioxide directly from the atmosphere, a moisture removal device for removing moisture from the atmosphere; a carbon dioxide capture device that adsorbs the carbon dioxide from the pretreated gas that has had the moisture removed by the moisture remover and has passed through the moisture remover; Equipped with The moisture removal device is a first moisture adsorbent that removes the moisture from the atmosphere; a second moisture adsorbent that removes the moisture from the atmosphere; and The carbon dioxide capture device a first carbon dioxide adsorbent that adsorbs the carbon dioxide from the pretreated gas; a second carbon dioxide adsorbent that adsorbs the carbon dioxide from the pretreated gas; and The pretreated gas that has passed through either the first moisture adsorbent or the second moisture adsorbent is guided to the carbon dioxide capture device, the concentrated gas containing the carbon dioxide that has been adsorbed by either the first carbon dioxide adsorbent or the second carbon dioxide adsorbent and then desorbed is guided toward a storage section that stores the carbon dioxide; A carbon dioxide recovery system characterized in that the recovered gas, which has passed through the other of the first carbon dioxide adsorbent and the second carbon dioxide adsorbent and has had the carbon dioxide recovered, is led to the other of the first moisture adsorbent and the second moisture adsorbent.

2. a state in which the pretreated gas that has passed through either the first moisture adsorbent or the second moisture adsorbent is introduced to the carbon dioxide capture device and a state in which the pretreated gas that has passed through the other of the first moisture adsorbent or the second moisture adsorbent is introduced to the carbon dioxide capture device are alternately switched over at predetermined time intervals; 2. The carbon dioxide recovery system according to claim 1, wherein a state in which the recovered gas is guided to the other of the first moisture adsorbent and the second moisture adsorbent and a state in which the recovered gas is guided to one of the first moisture adsorbent and the second moisture adsorbent are alternately switched at predetermined time intervals.

3. the carbon dioxide capture unit is a first carbon dioxide capture unit, the enriched gas is a first enriched gas; the recovered gas is a first recovered gas; a second carbon dioxide recovery unit that further adsorbs the carbon dioxide from the first concentrated gas; The second carbon dioxide capture device a third carbon dioxide adsorbent that further adsorbs the carbon dioxide from the first enriched gas; a fourth carbon dioxide adsorbent that further adsorbs the carbon dioxide from the first enriched gas; and The first enriched gas is directed to the second carbon dioxide capture unit; a second concentrated gas containing the carbon dioxide that has been adsorbed by either the third carbon dioxide adsorbent or the fourth carbon dioxide adsorbent and then desorbed is introduced into the storage section; 2. The carbon dioxide capture system according to claim 1, wherein the second captured gas that has passed through the other of the third carbon dioxide adsorbent and the fourth carbon dioxide adsorbent and has had the carbon dioxide captured is released into the atmosphere.

4. the carbon dioxide capture unit is a first carbon dioxide capture unit, the enriched gas is a first enriched gas; the recovered gas is a first recovered gas; a second carbon dioxide recovery unit that further adsorbs the carbon dioxide from the first concentrated gas; The second carbon dioxide capture device a third carbon dioxide adsorbent that further adsorbs the carbon dioxide from the first enriched gas; a fourth carbon dioxide adsorbent that further adsorbs the carbon dioxide from the first enriched gas; and The first enriched gas is directed to the second carbon dioxide capture unit; a second concentrated gas containing the carbon dioxide that has been adsorbed by either the third carbon dioxide adsorbent or the fourth carbon dioxide adsorbent and then desorbed is introduced into the storage section; 2. The carbon dioxide recovery system according to claim 1, wherein the second recovered gas that has passed through the other of the third carbon dioxide adsorbent and the fourth carbon dioxide adsorbent and from which the carbon dioxide has been recovered is further guided to the other of the first moisture adsorbent and the second moisture adsorbent.

5. 5. The carbon dioxide recovery system according to claim 1, wherein the first moisture adsorbent and the second moisture adsorbent are zeolite.

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