Pretreatment method, carbon dioxide capture method, and apparatus for carrying out these methods

Abstract

To maintain, over a long period of time, the moisture adsorption performance of a moisture adsorbent that removes moisture from exhaust gas containing moisture, carbon dioxide, and acid gas prior to carbon dioxide collection processing.SOLUTION: A pre-treatment device is provided with a dehumidification tower capable of removing moisture from exhaust gas. The dehumidification tower has a moisture adsorbent capable of adsorbing moisture, an acidic gas adsorbent capable of adsorbing acidic gas, and a dehumidification container in which the moisture adsorbent and the acidic gas adsorbent are loaded. The moisture adsorbent is loaded in a position closer to a second port side, from which the exhaust gas can flow out, than the acidic gas adsorbent in the dehumidification container. The moisture adsorbent is an adsorbent which contains alumina. The acidic gas adsorbent is an adsorbent which contains silica but does not contain alumina, or an adsorbent which contains silica and alumina at an (Si / Al) molar ratio of greater than 2.5.SELECTED DRAWING: Figure 1

Description

[Technical Field]

[0001] The present disclosure relates to pretreatment methods, carbon dioxide capture methods, and apparatus for carrying out these methods. [Background technology]

[0002] 2. Description of the Related Art In order to reduce carbon dioxide emissions from the viewpoint of protecting the global environment, equipment for recovering carbon dioxide contained in exhaust gases is being considered.

[0003] An example of equipment for recovering carbon dioxide from exhaust gas is disclosed in Patent Document 1 below. This equipment includes a pretreatment device and a carbon dioxide recovery device. The pretreatment device has a dehumidification tower capable of removing moisture from the exhaust gas. The dehumidification tower is filled with synthetic zeolite as a moisture adsorbent capable of adsorbing moisture. The carbon dioxide recovery device is filled with synthetic zeolite as a carbon dioxide adsorbent capable of adsorbing carbon dioxide.

[0004] Synthetic zeolite can adsorb moisture and carbon dioxide, so when exhaust gas containing moisture and carbon dioxide is passed through synthetic zeolite, the synthetic zeolite adsorbs the moisture and carbon dioxide in the exhaust gas, reducing the efficiency of carbon dioxide adsorption.

[0005] Therefore, in the equipment described in Patent Document 1, moisture is removed from the exhaust gas in a pretreatment device, and then the carbon dioxide in the pretreated gas from which moisture has been removed is adsorbed by a carbon dioxide adsorbent in a carbon dioxide recovery device. [Prior art documents] [Patent documents]

[0006] [Patent Document 1] Japanese Patent Application Publication No. 01-108106 Summary of the Invention [Problem to be solved by the invention]

[0007] In order to recover carbon dioxide from the pretreated gas discharged from the pretreatment device, it is preferable that the dew point of the pretreated gas be as low as possible, i.e., the moisture concentration in the pretreated gas be as low as possible.

[0008] It is also preferable that the moisture adsorbent in the pretreatment device maintains its moisture adsorption performance for a long period of time.

[0009] Therefore, an object of the present disclosure is to provide a technology that can lower the dew point of gas that has passed through a moisture adsorbent while maintaining the moisture adsorption performance of the moisture adsorbent for a long period of time. [Means for solving the problem]

[0010] In order to achieve the above object, one aspect of the present invention is a pretreatment device comprising: A pretreatment device capable of removing moisture from exhaust gas containing moisture, carbon dioxide, and acidic gases before treatment in a carbon dioxide recovery device, the pretreatment device comprising: a dehumidification tower capable of removing moisture from the exhaust gas; and a blower capable of sending the exhaust gas into the dehumidification tower. a first acid gas adsorption tower, a second acid gas adsorption tower, and a switching mechanism; The dehumidifying tower includes a moisture adsorbent capable of adsorbing moisture, an acid gas adsorbent capable of adsorbing acid gas, and a dehumidifying container filled with the moisture adsorbent and the acid gas adsorbent. The dehumidifying container has a first port through which the exhaust gas from the blower can flow in and a second port through which gas that has passed through the moisture adsorbent and the acid gas adsorbent can flow out as pretreated gas. The acid gas adsorbent is filled on the first port side of the dehumidifying container, and the moisture adsorbent is filled on the second port side of the acid gas adsorbent in the dehumidifying container. The moisture adsorbent is an adsorbent containing alumina. The acid gas adsorbent is an adsorbent containing silica but not alumina, or an adsorbent containing silica and alumina and having a (Si / Al) molar ratio > 2.5. The first acid gas adsorption tower and the second acid gas adsorption tower each include an acid gas adsorbent capable of adsorbing acid gases and a container filled with the acid gas adsorbent. The container of the first acid gas adsorption tower and the container of the second acid gas adsorption tower each include a first port through which the exhaust gas from the blower can flow in and a second port through which gas that has passed through the acid gas adsorbent can flow out. The switching mechanism is configured to be switchable between a first state in which the exhaust gas from the blower can be directed to the first port of the first acid gas adsorption tower and a second state in which the exhaust gas from the blower can be directed to the first port of the second acid gas adsorption tower. The gas flowing out from the second port of the first acid gas adsorption tower and the gas flowing out from the second port of the second acid gas adsorption tower can flow into the dehumidification tower through the first port of the dehumidification tower.

[0011] Representative moisture adsorbents include zeolite and silica gel. Silica gel is resistant to acidic gases. Therefore, even if silica gel is used as an adsorbent for adsorbing moisture from exhaust gases containing moisture and acidic gases, the dehumidifying performance of the silica gel does not decrease significantly. On the other hand, when an adsorbent containing alumina, such as zeolite, is used as an adsorbent for adsorbing moisture from exhaust gases containing moisture and acidic gases, the alumina binds with the acidic gases, thereby decreasing the dehumidifying performance of the adsorbent. In other words, adsorbents containing alumina have lower resistance to acidic gases than silica gel. As described above, from the viewpoint of resistance to acidic gases, adsorbents with a high silica content relative to the alumina content are preferred.

[0012] On the other hand, adsorbents containing alumina, such as zeolite, can lower the dew point of exhaust gas compared to silica gel. In other words, adsorbents containing alumina can lower the moisture concentration in exhaust gas compared to silica gel. As described above, from the perspective of lowering the dew point of gas, adsorbents with a relatively high alumina content relative to the silica content are preferred.

[0013] In this embodiment, from the viewpoint of lowering the dew point of the gas sent to the carbon dioxide capture unit, an adsorbent containing alumina is used as the moisture adsorbent.

[0014] However, since moisture adsorbents containing alumina have low resistance to acid gases, in this embodiment, the exhaust gas is passed through an acid gas adsorbent, exhaust After removing most of the acid gases from the gas, the gas is passed through the moisture adsorbent. Thus, the acid gas adsorbent serves to protect the moisture adsorbent used in this embodiment by adsorbing the acid gases.

[0015] As described above, in this embodiment, an adsorbent containing alumina is used as the moisture adsorbent, so that the dew point of the gas sent to the carbon dioxide capture device can be reduced. As described above, this adsorbent containing alumina has low resistance to acidic gases. However, in this embodiment, as described above, the exhaust gas is passed through the acidic gas adsorbent to remove most of the acidic gases in the exhaust gas before passing this gas through the moisture adsorbent, so that the moisture adsorption performance of the moisture adsorbent can be maintained for a long period of time.

[0016] To achieve the above object, one aspect of the invention is a carbon dioxide recovery facility, The carbon dioxide capture device includes the pretreatment device according to the above aspect and the carbon dioxide capture device, which includes a carbon dioxide adsorption tower into which the pretreated gas can flow and which is filled with a carbon dioxide adsorbent capable of adsorbing carbon dioxide in the pretreated gas, and an aspirator that draws a vacuum inside the carbon dioxide adsorption tower.

[0017] In the pretreatment device of this embodiment, the dew point of the gas sent to the carbon dioxide recovery device can be lowered, in other words, the moisture concentration in the gas can be reduced. This allows the carbon dioxide to be efficiently adsorbed by the carbon dioxide adsorbent in the carbon dioxide adsorption tower. The carbon dioxide adsorbed by the carbon dioxide adsorbent is recovered by vacuum suctioning the carbon dioxide adsorption tower with an aspirator.

[0018] In order to achieve the above object, one aspect of the present invention is a pretreatment method, A pretreatment method for removing moisture from exhaust gas containing moisture, carbon dioxide, and acidic gases prior to carbon dioxide capture treatment includes an acidic gas removal step in which the exhaust gas is passed through an acidic gas adsorbent capable of adsorbing acidic gases to remove the acidic gases from the exhaust gas, and a dehumidification step in which the exhaust gas that has undergone the acidic gas removal step is passed through a moisture adsorbent capable of adsorbing moisture to remove moisture from the acidic gas-removed gas, and the pretreated gas from which the acidic gases have been removed after moisture removal is subjected to the carbon dioxide capture treatment. The acidic gas adsorbent is an adsorbent that contains silica and does not contain alumina, or an adsorbent that contains silica and alumina and has a (Si / Al) molar ratio > 2.5. The moisture adsorbent is an adsorbent that contains alumina. The acid gas removal process includes a primary acid gas removal process and a secondary acid gas removal process. The primary acid gas removal process includes a first process of passing the exhaust gas through a first acid gas adsorbent capable of adsorbing acid gases to remove acid gases from the exhaust gas, and a second process of passing the exhaust gas through a second acid gas adsorbent capable of adsorbing acid gases to remove acid gases from the exhaust gas. The process further includes a determination process of determining whether either the first acid gas adsorbent or the second acid gas adsorbent has deteriorated, and a switching process of terminating one of the first and second processes in which the exhaust gas is passed through the one acid gas adsorbent and starting the other process if the determination process determines that the one acid gas adsorbent has deteriorated. The secondary acid gas removal process removes acid gases from the exhaust gas after the primary acid gas removal process.

[0019] In this embodiment, similar to the pretreatment device in the above embodiment, the dew point of the gas to be treated for carbon dioxide recovery can be reduced, and the moisture adsorption performance of the moisture adsorbent used in the pretreatment can be maintained for a long period of time.

[0020] In order to achieve the above object, one aspect of the present invention is a carbon dioxide recovery method, The pretreatment method according to the above aspect is performed while the carbon dioxide recovery process is performed. The carbon dioxide recovery process includes a carbon dioxide adsorption step of passing the pretreated gas through a carbon dioxide adsorbent capable of adsorbing carbon dioxide so that the carbon dioxide in the pretreated gas is adsorbed onto the carbon dioxide adsorbent, and a carbon dioxide desorption step of desorbing the carbon dioxide from the carbon dioxide adsorbent and recovering the carbon dioxide.

[0021] In this embodiment, the dew point of the gas to be subjected to the carbon dioxide recovery treatment can be lowered, in other words, the moisture concentration in the gas can be reduced. Therefore, the carbon dioxide can be efficiently adsorbed by the carbon dioxide adsorbent used in the carbon dioxide adsorption step. The carbon dioxide adsorbed by the carbon dioxide adsorbent is recovered by performing the carbon dioxide desorption step. [Effects of the Invention]

[0022] According to one aspect of the present disclosure, the dew point of gas that has passed through a moisture adsorbent can be lowered, while the moisture adsorption performance of the moisture adsorbent can be maintained for a long period of time. [Brief explanation of the drawings]

[0023] [Figure 1] 1 is a system diagram (part 1) of a carbon dioxide recovery facility in a first embodiment according to the present disclosure. [Figure 2] 2 is a system diagram (part 2) of the carbon dioxide recovery facility in the first embodiment according to the present disclosure. [Figure 3] 4 is a flowchart showing the operation of the carbon dioxide recovery facility in the first embodiment according to the present disclosure. [Figure 4] FIG. 10 is a system diagram of a carbon dioxide recovery facility in a second embodiment according to the present disclosure. [Figure 5] FIG. 10 is a system diagram of a carbon dioxide recovery facility in a third embodiment according to the present disclosure. [Figure 6] 10 is a flowchart showing the operation of the carbon dioxide recovery facility in the third embodiment according to the present disclosure. [Figure 7] FIG. 10 is a system diagram of a carbon dioxide recovery facility according to a fourth embodiment of the present disclosure. [Figure 8] 10 is a flowchart showing the operation of a carbon dioxide recovery facility in a fourth embodiment according to the present disclosure. DETAILED DESCRIPTION OF THE INVENTION

[0024] Various embodiments and various modified examples of the carbon dioxide recovery facility according to the present disclosure will be described below with reference to the drawings.

[0025] "First embodiment" A first embodiment of a carbon dioxide recovery facility will be described with reference to FIGS.

[0026] As shown in Fig. 1, the carbon dioxide recovery system in this embodiment is a system that recovers carbon dioxide from exhaust gas from an exhaust gas generation source 1. Examples of the exhaust gas generation source 1 include incinerators, coal-fired boilers, LNG-fired boilers, blast furnaces and converters in steel mills, kilns in cement factories, and gas turbines. The exhaust gas from these exhaust gas generation sources 1 contains nitrogen, oxygen, carbon dioxide, water, and acidic gases. Examples of acidic gases include HCl, SOx, and NOx. The type of acidic gas contained in the exhaust gas varies depending on the type of exhaust gas generation source.

[0027] This carbon dioxide capture facility includes a pretreatment device 10 and a carbon dioxide capture device 50. The pretreatment device 10 is a device that removes components from the exhaust gas that inhibit the capture of carbon dioxide in the carbon dioxide capture device 50. The carbon dioxide capture device 50 is a device that mainly captures carbon dioxide from the exhaust gas from the pretreatment device 10.

[0028] The pretreatment device 10 includes two dehumidification towers 11. Each of the two dehumidification towers 11 includes a dehumidification container 12 and an acid gas adsorbent 16 and a moisture adsorbent 17 packed in the dehumidification container 12. The acid gas adsorbent 16 is an adsorbent capable of adsorbing acid gases such as HCl, SOx, and NOx. The moisture adsorbent 17 is an adsorbent capable of adsorbing moisture. The dehumidification containers 12 of the two dehumidification towers each have a first port 12i and a second port 12o. The first port 12i is formed on one side of the dehumidification container 12 relative to the moisture adsorbent 17 and acid gas adsorbent 16, and the second port 12o is formed on the other side of the dehumidification container 12 relative to the moisture adsorbent 17 and acid gas adsorbent 16. The acidic gas adsorbent 16 is filled on the first port 12i side in the dehumidifying container 12, and the moisture adsorbent 17 is filled on the second port 12o side of the acidic gas adsorbent 16 in the dehumidifying container 12. In the following, one of the two dehumidifying towers 11 will be referred to as the first dehumidifying tower 11a, and the other will be referred to as the second dehumidifying tower 11b.

[0029] The carbon dioxide capture system 50 includes three carbon dioxide adsorption towers 51. Each of the three carbon dioxide adsorption towers 51 includes a container 52 and a carbon dioxide adsorbent 53 filled in the container 52. The containers 52 of the three carbon dioxide adsorption towers 51 each include a first port 52i and a second port 52o. The first port 52i is formed on one side of the container 52 relative to the carbon dioxide adsorbent 53, and the second port 52o is formed on the other side of the container 52 relative to the carbon dioxide adsorbent 53. Note that, hereinafter, one of the three carbon dioxide adsorption towers 51 will be referred to as a first carbon dioxide adsorption tower 51a, another as a second carbon dioxide adsorption tower 51b, and the remaining carbon dioxide adsorption tower 51 as a third carbon dioxide adsorption tower 51c.

[0030] In addition to the first dehumidification tower 11a and second dehumidification tower 11b described above, the pretreatment device 10 has a blower 6, a dehumidification vacuum pump 7, an exhaust gas line 20, a pretreated gas line 30, a moisture-rich gas line 34, an off-gas line 37, a first exhaust gas valve 41a, a second exhaust gas valve 41b, a dehumidification-side first pretreated gas valve 43a, a dehumidification-side second pretreated gas valve 43b, a first moisture-rich gas valve 44a, a second moisture-rich gas valve 44b, a dehumidification-side first off-gas valve 45a, and a dehumidification-side second off-gas valve 45b.

[0031] The exhaust gas line 20 includes a main exhaust gas line 21, a first exhaust gas line 22a, and a second exhaust gas line 22b. One end of the main exhaust gas line 21 is connected to the exhaust gas generation source 1. One end of the first exhaust gas line 22a and one end of the second exhaust gas line 22b are connected to the other end of the main exhaust gas line 21. Therefore, the first exhaust gas line 22a and the second exhaust gas line 22b are lines branching off from the main exhaust gas line 21. A blower 6 is provided in the main exhaust gas line 21. The other end of the first exhaust gas line 22a is connected to the first port 12i of the first dehumidification tower 11a, and the other end of the second exhaust gas line 22b is connected to the first port 12i of the second dehumidification tower 11b. A first exhaust gas valve 41a is provided in the first exhaust gas line 22a. A second exhaust gas valve 41b is provided in the second exhaust gas line 22b.

[0032] The pretreated gas line 30 includes a first dehumidification-side pretreated gas line 31a, a second dehumidification-side pretreated gas line 31b, a main pretreated gas line 32, a first recovery-side pretreated gas line 33a, a second recovery-side pretreated gas line 33b, and a third recovery-side pretreated gas line 33c. One end of the first dehumidification-side pretreated gas line 31a is connected to the second port 12o of the first dehumidification tower 11a, and one end of the second dehumidification-side pretreated gas line 31b is connected to the second port 12o of the second dehumidification tower 11b. A first dehumidification-side pretreated gas valve 43a is provided on the first dehumidification-side pretreated gas line 31a. A second dehumidification-side pretreated gas valve 43b is provided on the second dehumidification-side pretreated gas line 31b. One end of the main pretreated gas line 32 is connected to the other end of the dehumidification-side first pretreated gas line 31a and the other end of the dehumidification-side second pretreated gas line 31b. One end of the recovery-side first pretreated gas line 33a, one end of the recovery-side second pretreated gas line 33b, and one end of the recovery-side third pretreated gas line 33c are connected to the other end of the main pretreated gas line 32. Therefore, the recovery-side first pretreated gas line 33a, the recovery-side second pretreated gas line 33b, and the recovery-side third pretreated gas line 33c are lines branched from the main pretreated gas line 32. The other end of the recovery-side first pretreated gas line 33a is connected to a first port 52i of the first carbon dioxide adsorption tower 51a. The other end of the recovery-side second pretreated gas line 33b is connected to a first port 52i of the second carbon dioxide adsorption tower 51b. The other end of the recovery-side third pretreated gas line 33c is connected to the first port 52i of the third carbon dioxide adsorption tower 51c.

[0033] The moisture-rich gas line 34 includes a first moisture-rich gas line 35a, a second moisture-rich gas line 35b, and a main moisture-rich gas line 36. One end of the first moisture-rich gas line 35a is connected to the first exhaust gas line 22a at a position closer to the first dehumidification tower 11a than the first exhaust gas valve 41a. One end of the second moisture-rich gas line 35b is connected to the second exhaust gas line 22b at a position closer to the second dehumidification tower 11b than the second exhaust gas valve 41b. A first moisture-rich gas valve 44a is provided in the first moisture-rich gas line 35a, and a second moisture-rich gas valve 44b is provided in the second moisture-rich gas line 35b. One end of the main moisture-rich gas line 36 is connected to the other end of the first moisture-rich gas line 35a and the other end of the second moisture-rich gas line 35b. The other end of the main moisture-rich gas line 36 is connected to the suction port of the dehumidification vacuum pump 7.

[0034] The offgas line 37 includes a recovery-side first offgas line 38a, a recovery-side second offgas line 38b, a recovery-side third offgas line 38c, a main offgas line 38m, a dehumidification-side first offgas line 39a, and a dehumidification-side second offgas line 39b. One end of the recovery-side first offgas line 38a is connected to the second port 52o of the first carbon dioxide adsorption tower 51a. One end of the recovery-side second offgas line 38b is connected to the second port 52o of the second carbon dioxide adsorption tower 51b. One end of the recovery-side third offgas line 38c is connected to the second port 52o of the third carbon dioxide adsorption tower 51c. The other ends of the recovery-side first offgas line 38a, the recovery-side second offgas line 38b, and the recovery-side third offgas line 38c are connected to portions of one end of the main offgas line 38m. The other end of the main offgas line 38m is connected to one end of a dehumidification-side first offgas line 39a and one end of a dehumidification-side second offgas line 39b. The other end of the dehumidification-side first offgas line 39a is connected to the second port 12o of the first dehumidification tower 11a. The other end of the dehumidification-side second offgas line 39b is connected to the second port 12o of the second dehumidification tower 11b. A dehumidification-side first offgas valve 45a is provided on the dehumidification-side first offgas line 39a. A dehumidification-side second offgas valve 45b is provided on the dehumidification-side second offgas line 39b.

[0035] In addition to the first carbon dioxide adsorption tower 51a, second carbon dioxide adsorption tower 51b, and third carbon dioxide adsorption tower 51c described above, the carbon dioxide recovery device 50 also includes a blower 6, a pretreated gas line 30, an aspirator 55, a recovery side first pretreated gas valve 56a, a recovery side second pretreated gas valve 56b, a recovery side third pretreated gas valve 56c, a first suction valve 57a, a second suction valve 57b, a third suction valve 57c, a recovery side first off-gas valve 58a, a recovery side second off-gas valve 58b, a recovery side third off-gas valve 58c, a recovery tank 63, a suction line 65, an off-gas line 37, and a discharge line 68.

[0036] Of the components of the carbon dioxide capture device 50 , the blower 6 , the pretreated gas line 30 , and the off-gas line 37 are components of the carbon dioxide capture device 50 as well as components of the pretreatment device 10 .

[0037] The recovery side first pretreated gas valve 56a is provided on the recovery side first pretreated gas line 33a. The recovery side second pretreated gas valve 56b is provided on the recovery side second pretreated gas line 33b. The recovery side third pretreated gas valve 56c is provided on the recovery side third pretreated gas line 33c. The recovery side first off-gas valve 58a is provided on the recovery side first off-gas line 38a. The recovery side second off-gas valve 58b is provided on the recovery side second off-gas line 38b. The recovery side third off-gas valve 58c is provided on the recovery side third off-gas line 38c.

[0038] The suction line 65 includes a first suction line 66a, a second suction line 66b, a third suction line 66c, and a main suction line 67. One end of the first suction line 66a is connected to the recovery-side first pretreated gas line 33a at a position closer to the first carbon dioxide adsorption tower 51a than the recovery-side first pretreated gas valve 56a. A first suction valve 57a is provided in the first suction line 66a. One end of the second suction line 66b is connected to the recovery-side second pretreated gas line 33b at a position closer to the second carbon dioxide adsorption tower 51b than the recovery-side second pretreated gas valve 56b. A second suction valve 57b is provided in the second suction line 66b. One end of the third suction line 66c is connected to the recovery-side third pretreated gas line 33c at a position closer to the third carbon dioxide adsorption tower 51c than the recovery-side third pretreated gas valve 56c. A third suction valve 57c is provided in the third suction line 66c. The other end of the first suction line 66a, the other end of the second suction line 66b, and the other end of the third suction line 66c are connected to one end of a main suction line 67. The other end of the main suction line 67 is connected to a suction port of the suction machine 55.

[0039] The suction device 55 is, for example, a vacuum pump.

[0040] One end of the discharge line 68 is connected to the discharge port of the suction device 55. The other end of the discharge line 68 is connected to the recovery tank 63.

[0041] In this embodiment, an adsorbent containing silica but not containing alumina, or an adsorbent containing silica and alumina with a (Si / Al) molar ratio of >2.5, is used as the acidic gas adsorbent 16. In this embodiment, an adsorbent containing alumina is used as the moisture adsorbent 17. In this embodiment, for example, zeolite is used as the carbon dioxide adsorbent.

[0042] Next, the operation of the carbon dioxide recovery facility described above will be described with reference to the flowchart shown in FIG.

[0043] The carbon dioxide capture facility performs pretreatment S10 and carbon dioxide capture treatment S20. The pretreatment S10 is performed by the pretreatment device 10, and the carbon dioxide capture treatment S20 is performed by the carbon dioxide capture device 50.

[0044] In the pretreatment S10, an acid gas removal step S11, a dehumidification step S12, and a regeneration step S13 are performed. Let us assume that the moisture adsorption amount of the moisture adsorbent 17 in the first dehumidification tower 11a is extremely small, and the moisture adsorption amount of the moisture adsorbent 17 in the second dehumidification tower 11b is large. In this case, as shown in FIG. 1 , the first exhaust gas valve 41a is open, the second exhaust gas valve 41b is closed, the dehumidification-side first pretreated gas valve 43a is open, the dehumidification-side second pretreated gas valve 43b is closed, the first moisture-rich gas valve 44a is closed, the second moisture-rich gas valve 44b is open, the dehumidification-side first off-gas valve 45a is closed, and the dehumidification-side second off-gas valve 45b is open.

[0045] In this case, exhaust gas from the exhaust gas generation source 1 flows into the first dehumidifier 11a via the main exhaust gas line 21, the blower 6, the first exhaust gas line 22a, and the first exhaust gas valve 41a. The exhaust gas that flows into the first dehumidifier 11a first passes through the acid gas adsorbent 16 in the first dehumidifier 11a. As the exhaust gas passes through the acid gas adsorbent 16, most of the acid gases contained in the exhaust gas are adsorbed by the acid gas adsorbent 16 (acid gas removal step S11). The exhaust gas that has passed through the acid gas adsorbent 16, i.e., the gas from which the acid gases have been removed, passes through the moisture adsorbent 17 in the first dehumidifier 11a. As the gas from which the acid gases have been removed passes through the moisture adsorbent 17, most of the moisture contained in the gas from which the acid gases have been removed is adsorbed by the moisture adsorbent 17, and the remainder is discharged from the first dehumidifier 11a as a pretreated gas. That is, in the first dehumidifier 11a, the acid gases and moisture in the exhaust gas are removed. This pretreated gas is sent to the carbon dioxide capture device 50 via the dehumidification-side first pretreated gas line 31 a, the dehumidification-side first pretreated gas valve 43 a, and the main pretreated gas line 32.

[0046] Furthermore, in this case, the moisture-poor off-gas from the carbon dioxide capture unit 50 flows into the second dehumidification tower 11b via the main off-gas line 38m, the dehumidification-side second off-gas line 39b, and the dehumidification-side second off-gas valve 45b. The off-gas that flows into the second dehumidification tower 11b passes through the moisture adsorbent 17 in the second dehumidification tower 11b. As the off-gas passes through the moisture adsorbent 17, it releases moisture from the moisture adsorbent 17. As a result, the off-gas becomes moisture-rich. The moisture-rich gas passes through the acid gas adsorbent 16 in the second dehumidification tower 11b. As the moisture-rich gas passes through the acid gas adsorbent 16, it releases acid gases from the acid gas adsorbent 16. As a result, the moisture-rich gas becomes moisture- and acid gas-rich gas. The moisture- and acid gas-rich gas is exhausted from the second dehumidification tower 11b. That is, in the second dehumidification tower 11b, the moisture adsorbent 17 and the acidic gas adsorbent 16 are regenerated. The gas rich in moisture and acidic gas is released to the outside via the second moisture-rich gas line 35b, the second moisture-rich gas valve 44b, the main moisture-rich gas line 36, and the dehumidification vacuum pump 7 (regeneration step S13). The gas rich in moisture and acidic gas may be released to the atmosphere or a tank.

[0047] As described above, when the acid gas removal step S11 and the dehumidification step S12 are performed in the first dehumidification tower 11a, the amount of moisture adsorbed by the moisture adsorbent 17 in the first dehumidification tower 11a increases, and the amount of acid gas adsorbed by the acid gas adsorbent 16 in the first dehumidification tower 11a increases. Also, when the regeneration step S13 is performed in the second dehumidification tower 11b, the amount of moisture adsorbed by the moisture adsorbent 17 in the second dehumidification tower 11b becomes extremely small, and the amount of acid gas adsorbed by the acid gas adsorbent 16 in the second dehumidification tower 11b becomes extremely small.

[0048] Also, suppose that the moisture adsorption amount of the moisture adsorbent 17 in the first dehumidification tower 11a is large and the moisture adsorption amount of the moisture adsorbent 17 in the second dehumidification tower 11b is extremely small. In this case, as shown in Fig. 2, the first exhaust gas valve 41a is closed, the second exhaust gas valve 41b is open, the dehumidification-side first pretreated gas valve 43a is closed, the dehumidification-side second pretreated gas valve 43b is open, the first moisture-rich gas valve 44a is open, the second moisture-rich gas valve 44b is closed, the dehumidification-side first off-gas valve 45a is open, and the dehumidification-side second off-gas valve 45b is open. 45b becomes closed.

[0049] In this case, exhaust gas from the exhaust gas generation source 1 flows into the second dehumidification tower 11b via the main exhaust gas line 21, the blower 6, the second exhaust gas line 22b, and the second exhaust gas valve 41b. The exhaust gas that flows into the second dehumidification tower 11b first passes through the acid gas adsorbent 16 in the second dehumidification tower 11b. As the exhaust gas passes through the acid gas adsorbent 16, most of the acid gases contained in the exhaust gas are adsorbed by the acid gas adsorbent 16 (acid gas removal step S11). The exhaust gas that has passed through the acid gas adsorbent 16, i.e., the gas from which the acid gases have been removed, passes through the moisture adsorbent 17 in the second dehumidification tower 11b. As the gas from which the acid gases have been removed passes through the moisture adsorbent 17, most of the moisture contained in the gas from which the acid gases have been removed is adsorbed by the moisture adsorbent 17, and the remainder is discharged from the second dehumidification tower 11b as a pretreated gas. That is, in the second dehumidification tower 11b, the acid gases and moisture in the exhaust gas are removed. This pretreated gas is sent to the carbon dioxide recovery unit 50 via the dehumidification-side second pretreated gas line 31b, the dehumidification-side second pretreated gas valve 43b, and the main pretreated gas line 32 (dehumidification step S12).

[0050] Furthermore, in this case, moisture-poor off-gas flows from the carbon dioxide capture unit 50 into the first dehumidification tower 11a via the main off-gas line 38m, the dehumidification-side first off-gas line 39a, and the dehumidification-side first off-gas valve 45a. The off-gas that flows into the first dehumidification tower 11a passes through the moisture adsorbent 17 in the first dehumidification tower 11a. As the off-gas passes through the moisture adsorbent 17, it releases moisture from the moisture adsorbent 17. As a result, the off-gas becomes moisture-rich. The moisture-rich gas passes through the acid gas adsorbent 16 in the first dehumidification tower 11a. As the moisture-rich gas passes through the acid gas adsorbent 16, it releases acid gases from the acid gas adsorbent 16. As a result, the moisture-rich gas becomes moisture- and acid gas-rich gas. The moisture- and acid gas-rich gas is exhausted from the first dehumidification tower 11a. That is, in the first dehumidification tower 11a, the moisture adsorbent 17 and the acidic gas adsorbent 16 are regenerated. The gas rich in moisture and acidic gas is released to the outside via the first moisture-rich gas line 35a, the first moisture-rich gas valve 44a, the main moisture-rich gas line 36, and the dehumidification vacuum pump 7 (regeneration step S13).

[0051] As described above, in the first dehumidification tower 11a and the second dehumidification tower 11b of the pretreatment device 10, the dehumidification step S12 is performed after the acid gas removal step S11, the regeneration step S13 is performed after the dehumidification step S12, and the acid gas removal step S11 is performed after the regeneration step S13. Furthermore, when the acid gas removal step S11 and the dehumidification step S12 are performed in the first dehumidification tower 11a, the regeneration step S13 is performed in the second dehumidification tower 11b. Furthermore, when the acid gas removal step S11 and the dehumidification step S12 are performed in the second dehumidification tower 11b, the regeneration step S13 is performed in the first dehumidification tower 11a. Therefore, in this embodiment, acid gases and moisture in the exhaust gas can be continuously removed.

[0052] In the carbon dioxide recovery process S20, an adsorption step S21, a desorption step S22, and a pressurization step S23 are performed. It is assumed that the carbon dioxide adsorption amounts of the carbon dioxide adsorbent 53 in the first carbon dioxide adsorption tower 51a and the carbon dioxide adsorbent 53 in the second carbon dioxide adsorption tower 51b are extremely small, and that the carbon dioxide adsorption amount of the carbon dioxide adsorbent 53 in the third carbon dioxide adsorption tower 51c is large. Furthermore, it is assumed that the pressure inside the first carbon dioxide adsorption tower 51a is negative, and the pressure inside the second carbon dioxide adsorption tower 51b is approximately atmospheric. In this case, as shown in FIG. 1, the recovery side first pre-treated gas valve 56a is in a closed state, the recovery side second pre-treated gas valve 56b is in an open state, the recovery side third pre-treated gas valve 56c is in a closed state, the first suction valve 57a is in a closed state, the second suction valve 57b is in a closed state, the third suction valve 57c is in an open state, the recovery side first off-gas valve 58a is in a half-open state, the recovery side second off-gas valve 58b is in an open state, and the recovery side third off-gas valve 58c is in a closed state.

[0053] In this case, the pretreated gas from the pretreatment device 10 flows into the second carbon dioxide adsorption tower 51b via the main pretreated gas line 32, the recovery-side second pretreated gas line 33b, and the recovery-side second pretreated gas valve 56b. As the pretreated gas that flows into the second carbon dioxide adsorption tower 51b passes through the carbon dioxide adsorbent 53 in the second carbon dioxide adsorption tower 51b, much of the carbon dioxide contained in the pretreated gas is adsorbed by the carbon dioxide adsorbent 53, and the remainder is discharged from the second carbon dioxide adsorption tower 51b as off-gas. That is, the carbon dioxide adsorbent 53 in the second carbon dioxide adsorption tower 51b adsorbs the carbon dioxide in the pretreated gas (adsorption step S21). A portion of the off-gas discharged from the second carbon dioxide adsorption tower 51b is sent to the dehumidification tower 11 in the regeneration step S13 via the recovery-side second off-gas line 38b, the recovery-side second off-gas valve 58b, and the main off-gas line 38m.

[0054] Furthermore, a remaining portion of the offgas discharged from the second carbon dioxide adsorption tower 51b is sent to the first carbon dioxide adsorption tower 51a via the recovery-side second offgas line 38b, the recovery-side second offgas valve 58b, the main offgas line 38m, the recovery-side first offgas line 38a, and the recovery-side first offgas valve 58a. As a result, the pressure inside the first carbon dioxide adsorption tower 51a is increased from negative pressure to approximately atmospheric pressure (pressure increase step S23).

[0055] Furthermore, in this case, the inside of the third carbon dioxide adsorption tower 51c is vacuum-suctioned by the aspirator 55 via the third suction line 66c, the third suction valve 57c, and the main suction line 67. As a result, the carbon dioxide adsorbed to the carbon dioxide adsorbent 53 in the third carbon dioxide adsorption tower 51c is desorbed and discharged from the aspirator 55. This gas containing carbon dioxide is sent to the recovery tank 63 via the discharge line 68 (desorption step S22).

[0056] As described above, when the adsorption step S21 is performed in the second carbon dioxide adsorption tower 51b, the amount of carbon dioxide adsorbed by the carbon dioxide adsorbent 53 in the second carbon dioxide adsorption tower 51b increases. Furthermore, when the desorption step S22 is performed in the third carbon dioxide adsorption tower 51c, the amount of carbon dioxide adsorbed by the carbon dioxide adsorbent 53 in the third carbon dioxide adsorption tower 51c becomes extremely small, and the inside of the third carbon dioxide adsorption tower 51c becomes negative pressure. Furthermore, when the pressurization step S23 is performed in the first carbon dioxide adsorption tower 51a, the inside of the first carbon dioxide adsorption tower 51a becomes approximately atmospheric pressure. Note that at this time, the amount of carbon dioxide adsorbed by the carbon dioxide adsorbent 53 in the first carbon dioxide adsorption tower 51a is extremely small.

[0057] Also, suppose that the carbon dioxide adsorption amounts of the carbon dioxide adsorbent 53 in the first carbon dioxide adsorption tower 51a and the carbon dioxide adsorbent 53 in the third carbon dioxide adsorption tower 51c are extremely small, and that the carbon dioxide adsorption amount of the carbon dioxide adsorbent 53 in the second carbon dioxide adsorption tower 51b is large. Furthermore, suppose that the pressure inside the first carbon dioxide adsorption tower 51a is approximately atmospheric, and the pressure inside the third carbon dioxide adsorption tower 51c is negative. In this case, as shown in FIG. 2 , the recovery-side first pretreated gas valve 56a is open, the recovery-side second pretreated gas valve 56b is closed, the recovery-side third pretreated gas valve 56c is closed, the first suction valve 57a is closed, the second suction valve 57b is open, the third suction valve 57c is closed, the recovery-side first off-gas valve 58a is open, the recovery-side second off-gas valve 58b is closed, and the recovery-side third off-gas valve 58c is half-open.

[0058] In this case, the pretreated gas from the pretreatment device 10 flows into the first carbon dioxide adsorption tower 51a via the main pretreated gas line 32, the recovery-side first pretreated gas line 33a, and the recovery-side first pretreated gas valve 56a. As the pretreated gas that flows into the first carbon dioxide adsorption tower 51a passes through the carbon dioxide adsorbent 53 in the first carbon dioxide adsorption tower 51a, much of the carbon dioxide contained in the pretreated gas is adsorbed by the carbon dioxide adsorbent 53, and the remainder is discharged from the first carbon dioxide adsorption tower 51a as off-gas. That is, the carbon dioxide adsorbent 53 in the first carbon dioxide adsorption tower 51a adsorbs the carbon dioxide in the pretreated gas (adsorption step S21). A portion of the off-gas discharged from the first carbon dioxide adsorption tower 51a is sent to the dehumidification tower 11 in the regeneration step S13 via the recovery-side first off-gas line 38a, the recovery-side first off-gas valve 58a, and the main off-gas line 38m.

[0059] Furthermore, a remaining portion of the offgas discharged from the first carbon dioxide adsorption tower 51a is sent to the third carbon dioxide adsorption tower 51c via the recovery-side first offgas line 38a, the recovery-side first offgas valve 58a, the main offgas line 38m, the recovery-side third offgas line 38c, and the recovery-side third offgas valve 58c. As a result, the pressure inside the third carbon dioxide adsorption tower 51c is increased from negative pressure to approximately atmospheric pressure (pressure increase step S23).

[0060] Furthermore, in this case, the inside of second carbon dioxide adsorption tower 51b is vacuum-suctioned by aspirator 55 via second suction line 66b, second suction valve 57b, and main suction line 67. As a result, the carbon dioxide adsorbed to carbon dioxide adsorbent 53 in second carbon dioxide adsorption tower 51b is desorbed and discharged from aspirator 55. This gas containing carbon dioxide is sent to recovery tank 63 via discharge line 68 (desorption step S22).

[0061] As described above, in the first carbon dioxide adsorption tower 51a, the second carbon dioxide adsorption tower 51b, and the third carbon dioxide adsorption tower 51c of the carbon dioxide recovery system 50, the desorption step S22 is performed after the adsorption step S21, the pressurization step S23 is performed after the desorption step S22, and the adsorption step S21 is performed after the pressurization step S23. Furthermore, when the adsorption step S21 is being performed in the second carbon dioxide adsorption tower 51b, the desorption step S22 is performed in the third carbon dioxide adsorption tower 51c, and the pressurization step S23 is performed in the first carbon dioxide adsorption tower 51a. Furthermore, when the amount of carbon dioxide adsorbed by the carbon dioxide adsorbent 53 in the second carbon dioxide adsorption tower 51b becomes large, the desorption step S22 is performed in the second carbon dioxide adsorption tower 51b, the pressurization step S23 is performed in the third carbon dioxide adsorption tower 51c, and the adsorption step S21 is performed in the first carbon dioxide adsorption tower 51a. Therefore, in this embodiment, carbon dioxide in the pretreated gas can be continuously recovered.

[0062] In this embodiment, as described above, the pressurization step S23 is performed after the desorption step S22. The degree of vacuum in the carbon dioxide adsorption tower 51 after the desorption step S22 is high. For this reason, if the adsorption step S21 is performed while the degree of vacuum remains high, even if exhaust gas is sent into the carbon dioxide adsorption tower 51, the exhaust gas will blow through the carbon dioxide adsorbent 53, reducing the carbon dioxide adsorption efficiency. Therefore, in this embodiment, the pressurization step S23 is performed after the desorption step S22, and then the adsorption step S21 is performed.

[0063] Furthermore, in this embodiment, an adsorbent replacement process S30 for the adsorbent in the pretreatment device 10 is also performed. This adsorbent replacement process S30 is a process performed by an operator. The operator determines whether the acid gas adsorbent 16 and the moisture adsorbent 17 satisfy predetermined replacement conditions (determination step S31).

[0064] In this determination step S31, for example, a portion of the acid gas adsorbent 16 and a portion of the moisture adsorbent 17 in the dehumidification tower 11 are sampled, and the sampled adsorbents are analyzed. There are various methods for analyzing adsorbents, but here, the sampled adsorbent is analyzed by an X-ray microanalysis method. This X-ray microanalysis method is a method in which a sample (the sampled adsorbent) is irradiated with an electron beam and the characteristic X-rays generated are measured to perform elemental analysis. If the result of this analysis shows that the degree of deterioration of the sampled adsorbent is equal to or greater than a predetermined level, it is determined that the replacement conditions are met.

[0065] Alternatively, in this determination step S31, the adsorbent may not be analyzed as described above, and the replacement condition may be satisfied if the period since the previous adsorbent replacement is equal to or longer than a predetermined period. Alternatively, in this determination step S31, the replacement condition may be satisfied if the cumulative amount of gas that has passed through the replaced adsorbent since the previous adsorbent replacement is equal to or longer than a predetermined amount.

[0066] When the worker determines that the replacement conditions are met, the worker replaces the adsorbent that satisfies the replacement conditions with a new adsorbent (replacement step S32).

[0067] The adsorbent replacement process S30 is also performed on the adsorbent in the carbon dioxide capture device 50 in the same manner as above.

[0068] Here, we will explain about zeolite. Zeolite is a general term for crystalline aluminosilicate. The chemical formula of zeolite can be expressed as follows: Me2 / xO·Al2O3·mSiO2·nH2O Me: X-valent cation Thus, zeolites contain silica (SiO2) and alumina (Al2O3).

[0069] Zeolite crystal structures are not uniform and include, for example, A-type, X-type, Y-type, USY (Ultra-stable Y)-type, and beta-type. Furthermore, Na ions, Li ions, Ca ions, and the like are used as Me in the above chemical formulas. Therefore, there are various types of zeolite depending on the differences in their crystal structures and cations.

[0070] Among zeolites, zeolites with a relatively low silica content relative to alumina are called low-silica zeolites. These low-silica zeolites have a (Si / Al) molar ratio of less than 2. Examples of low-silica zeolites include some A-type zeolites and some X-type zeolites. Furthermore, among zeolites, zeolites with a high silica content relative to alumina are called high-silica zeolites. These high-silica zeolites have a (Si / Al) molar ratio of greater than 2.5. Examples of high-silica zeolites include Y-type, USY (Ultra-stable Y)-type, and beta-type.

[0071] When zeolite comes into contact with acidic gases, the alumina in the zeolite binds with the acidic gas, reducing the zeolite's moisture adsorption performance. Therefore, the more alumina there is in the zeolite (the smaller the (Si / Al) molar ratio), the greater the tendency for its moisture adsorption performance to decrease when it comes into contact with acidic gases. In other words, zeolites with a high alumina content (low (Si / Al) molar ratio) have low resistance to acidic gases. Conversely, zeolites with a low alumina content (high ((Si / Al) molar ratio) have high resistance to acidic gases.

[0072] Furthermore, adsorbents containing alumina, such as zeolite, have a stronger moisture adsorption capacity than high-silica adsorbents, and can lower the dew point of exhaust gas. In other words, adsorbents containing alumina can lower the moisture concentration in exhaust gas compared to high-silica adsorbents. Therefore, the more alumina a zeolite contains (the smaller the (Si / Al) molar ratio), the better its ability to lower the dew point of exhaust gas tends to be.

[0073] In order to stabilize the amount of carbon dioxide adsorbed by the carbon dioxide adsorbent, it is preferable that the dew point of the gas passing through the carbon dioxide adsorbent is low, in other words, that the water concentration in this gas is low.

[0074] Therefore, in this embodiment, before the exhaust gas is sent to the carbon dioxide capture device 50, the moisture in the exhaust gas is adsorbed by the moisture adsorbent 17 of the pretreatment device 10.

[0075] In addition to the zeolite described above, silica gel is a typical moisture adsorbent. This silica gel is resistant to acidic gases. Therefore, even if silica gel is used as an adsorbent for adsorbing moisture from exhaust gas containing moisture and acidic gases, the dehumidifying performance of this silica gel does not decrease significantly. On the other hand, if an adsorbent containing alumina is used as an adsorbent for adsorbing moisture from exhaust gas containing moisture and acidic gases, the alumina will bind to the acidic gases, thereby decreasing the dehumidifying performance of this adsorbent. In other words, as mentioned above, adsorbents containing alumina have lower resistance to acidic gases than silica gel. As described above, from the viewpoint of resistance to acidic gases, adsorbents with a high silica content relative to the alumina content are preferred.

[0076] On the other hand, an adsorbent containing alumina can lower the dew point of exhaust gas compared to silica gel. In other words, an adsorbent containing alumina can lower the moisture concentration in exhaust gas compared to silica gel. As described above, from the viewpoint of lowering the dew point of gas, an adsorbent having a relatively high alumina content relative to the silica content is preferred.

[0077] In this embodiment, from the viewpoint of lowering the dew point of the gas sent to the carbon dioxide capture unit 50, an adsorbent containing alumina is used as the moisture adsorbent 17, as described above. Examples of adsorbents containing alumina include activated alumina and the zeolite described above. When using zeolite as the moisture adsorbent 17, it is preferable to use, among the multiple types of zeolite, an X-type zeolite classified as a low-silica zeolite with a (Si / Al) molar ratio of less than 2.

[0078] However, since the moisture adsorbent 17 containing alumina has low resistance to acidic gases, in this embodiment, the exhaust gas is passed through the acidic gas adsorbent 16 to remove most of the acidic gases from the exhaust gas before passing the gas through the moisture adsorbent 17. Therefore, the acidic gas adsorbent 16 serves to protect the moisture adsorbent 17 used in this embodiment by adsorbing acidic gases. Since the acidic gas adsorbent 16 is desired to have high resistance to acidic gases, this embodiment uses an adsorbent containing silica but not alumina, or an adsorbent containing silica and alumina with a (Si / Al) molar ratio > 2.5. An example of an adsorbent containing silica but not alumina is silica gel. Another example of an adsorbent containing silica and alumina with a (Si / Al) molar ratio > 2.5 is high-silica zeolite. When zeolite is used as the acidic gas adsorbent 16, it is preferable to use a Y-type, USY-type, or beta-type zeolite that has a (Si / Al) molar ratio of >5 and is classified as high-silica zeolite.

[0079] As described above, in this embodiment, an adsorbent containing alumina is used as the moisture adsorbent 17, so that the dew point of the gas sent to the carbon dioxide capture device 50 can be reduced. This moisture adsorbent 17 containing alumina has low resistance to acidic gases. However, in this embodiment, the exhaust gas is passed through the acidic gas adsorbent 16 to remove most of the acidic gases in the exhaust gas, and then the gas is passed through the moisture adsorbent 17, so that the moisture adsorption performance of the moisture adsorbent 17 can be maintained for a long period of time.

[0080] Second Embodiment A second embodiment of the carbon dioxide recovery facility will be described with reference to FIG.

[0081] 4, the carbon dioxide capture system of the present embodiment includes a pretreatment device 10A and a carbon dioxide capture device 50, similar to the carbon dioxide capture system of the first embodiment. The carbon dioxide capture device 50 of the present embodiment is the same as the carbon dioxide capture device 50 of the first embodiment. On the other hand, the pretreatment device 10A of the present embodiment is different from the pretreatment device 10 of the first embodiment.

[0082] The dehumidifying container 12 of the pretreatment device 10 in the first embodiment is a single container. On the other hand, the dehumidifying container 12A of the dehumidifying tower 11A of the pretreatment device 10A in the present embodiment is composed of two containers: an acidic gas adsorbent container 13 and a moisture adsorbent container 15. The acidic gas adsorbent container 13 is filled with an acidic gas adsorbent 16. The moisture adsorbent container 15 is filled with a moisture adsorbent 17.

[0083] The acidic gas adsorbent container 13 has a first port 13i through which exhaust gas from the blower 6 can flow in and a second port 13o through which the gas from which acid gases have been removed, which is gas that has passed through the acidic gas adsorbent 16, can flow out. The moisture adsorbent container 15 has a first port 15i through which the gas from which acid gases have been removed can flow in and a second port 15o through which the pretreated gas, which is gas that has passed through the moisture adsorbent 17, can flow out. The first port 13i of the acidic gas adsorbent container 13 is the first port 12i of the dehumidifying container 12A. The second port 15o of the moisture adsorbent container 15 is the second port 12o of the dehumidifying container 12A.

[0084] The second port 13o of the acidic gas adsorbent container 13 that constitutes part of the dehumidification container 12A of the first dehumidification tower 11Aa is connected to the first port 15i of the moisture adsorbent container 15 that constitutes the other part of the dehumidification container 12A of the first dehumidification tower 11Aa by a first acidic gas-removed gas line 26a. The second port 13o of the acidic gas adsorbent container 13 that constitutes part of the dehumidification container 12A of the second dehumidification tower 11Ab is connected to the first port 15i of the moisture adsorbent container 15 that constitutes the other part of the dehumidification container 12A of the second dehumidification tower 11Ab by a second acidic gas-removed gas line 26b.

[0085] As described above, even if the dehumidifying container 12A is composed of two containers, the exhaust gas can be passed through the acidic gas adsorbent 16 and then through the moisture adsorbent 17, so that the same effect as in the first embodiment can be obtained in this embodiment.

[0086] "Third embodiment" A third embodiment of the carbon dioxide recovery facility will be described with reference to FIGS.

[0087] 5, the carbon dioxide capture system of the present embodiment, like the carbon dioxide capture systems of the above-described embodiments, includes a pretreatment device 10B and a carbon dioxide capture device 50. The carbon dioxide capture device 50 of the present embodiment is the same as the carbon dioxide capture device 50 of the above-described embodiments. On the other hand, the pretreatment device 10B of the present embodiment is different from the pretreatment device 10 of the first embodiment.

[0088] The dehumidifying container 12 of the pretreatment device 10 in the first embodiment is a single container. On the other hand, the dehumidifying container 12B of the pretreatment device 10B in the present embodiment is composed of three containers: a first acidic gas adsorbent container 13a, a second acidic gas adsorbent container 13b, and a moisture adsorbent container 15. The first acidic gas adsorbent container 13a and the second acidic gas adsorbent container 13b are filled with an acidic gas adsorbent 16. The moisture adsorbent container 15 is filled with a moisture adsorbent 17.

[0089] The first acidic gas adsorbent container 13a and the second acidic gas adsorbent container 13b each have a first port 13i through which exhaust gas from the blower 6 can flow in and a second port 13o through which gas from which acid gases have been removed, which is gas that has passed through the acidic gas adsorbent 16, can flow out. The moisture adsorbent container 15 also has a first port 15i through which gas from which acid gases have been removed can flow in and a second port 15o through which pretreated gas, which is gas that has passed through the moisture adsorbent 17, can flow out. The first port 12i of the first acidic gas adsorbent container 13a and the first port 13i of the second acidic gas adsorbent container 13b correspond to the first port 12i of the dehumidifying container 12B. The second port 15o of the moisture adsorbent container 15 corresponds to the second port 12o of the dehumidifying container 12B.

[0090] The exhaust gas line 20B in this embodiment includes a main exhaust gas line 21, a first exhaust gas line 22Ba, a second exhaust gas line 22Bb, a first branch exhaust gas line 23aa and a second branch exhaust gas line 23ba branching from the first exhaust gas line 22Ba, and a first branch exhaust gas line 23ab and a second branch exhaust gas line 23bb branching from the second exhaust gas line 22Bb. Similar to the one end of the main exhaust gas line 21 in each of the above embodiments, one end of the main exhaust gas line 21 is connected to the exhaust gas generation source 1. One ends of the first exhaust gas line 22Ba and the second exhaust gas line 22Bb are connected to the other end of the main exhaust gas line 21. A first exhaust gas valve 41a is provided in the first exhaust gas line 22Ba. A second exhaust gas valve 41b is provided in the second exhaust gas line 22Bb.

[0091] The other end of the first exhaust gas line 22Ba is connected to one end of a first branch exhaust gas line 23aa and one end of a second branch exhaust gas line 23ba. The other end of the first branch exhaust gas line 23aa is connected to a first port 13i of a first acidic gas adsorbent container 13a, which constitutes a part of the dehumidification container 12B of the first dehumidification tower 11Ba. The other end of the second branch exhaust gas line 23ba is connected to a first port 13i of a second acidic gas adsorbent container 13b, which constitutes a part of the dehumidification container 12B of the first dehumidification tower 11Ba. A first branch exhaust gas valve 42aa is provided in the first branch exhaust gas line 23aa. A second branch exhaust gas valve 42ba is provided in the second branch exhaust gas line 23ba.

[0092] The other end of the second exhaust gas line 22Bb is connected to one end of a first branch exhaust gas line 23ab and one end of a second branch exhaust gas line 23bb. The other end of the first branch exhaust gas line 23ab is connected to a first port 13i of a first acidic gas adsorbent container 13a that constitutes a part of the dehumidification container 12B of the second dehumidification tower 11Bb. The other end of the second branch exhaust gas line 23bb is connected to a first port 13i of a second acidic gas adsorbent container 13b that constitutes a part of the dehumidification container 12B of the second dehumidification tower 11Bb. A first branch exhaust gas valve 42ab is provided on the first branch exhaust gas line 23ab. A second branch exhaust gas valve 42bb is provided on the second branch exhaust gas line 23bb.

[0093] The second port 13o of the first acidic gas adsorbent container 13a, which constitutes a part of the dehumidification container 12B of the first dehumidification tower 11Ba, and the first port 15i of the moisture adsorbent container 15, which constitutes another part of the dehumidification container 12B of the first dehumidification tower 11Ba, are connected by a first a acidic gas-removed gas line 26aa. The second port 13o of the second acidic gas adsorbent container 13b, which constitutes a part of the dehumidification container 12B of the first dehumidification tower 11Ba, and the first port 15i of the moisture adsorbent container 15, which constitutes another part of the dehumidification container 12B of the first dehumidification tower 11Ba, are connected by a first b acidic gas-removed gas line 26ab.

[0094] The second port 13o of the first acidic gas adsorbent container 13a, which constitutes a part of the dehumidification container 12B of the second dehumidification tower 11Bb, and the first port 15i of the moisture adsorbent container 15, which constitutes another part of the dehumidification container 12B of the second dehumidification tower 11Bb, are connected by a second a acidic gas-removed gas line 26ba. The second port 13o of the second acidic gas adsorbent container 13b, which constitutes a part of the dehumidification container 12B of the second dehumidification tower 11Bb, and the first port 15i of the moisture adsorbent container 15, which constitutes another part of the dehumidification container 12B of the second dehumidification tower 11Bb, are connected by a second b acidic gas-removed gas line 26bb.

[0095] The pretreatment device 10B of this embodiment has a switching mechanism 29B that is configured to be able to switch between a first state in which exhaust gas from the blower 6 can be guided to the first port 13i of the first acidic gas adsorbent container 13a and a second state in which exhaust gas from the blower 6 can be guided to the first port 13i of the second acidic gas adsorbent container 13b. This switching mechanism 29B is configured to have the first branch exhaust gas lines 23aa, 23ab, second branch exhaust gas lines 23ba, 23bb, first branch exhaust gas valves 42aa, 42ab, and second branch exhaust gas valves 42ba, 42bb, as described above.

[0096] Next, the operation of the carbon dioxide recovery facility described above will be described with reference to the flowchart shown in FIG.

[0097] The carbon dioxide capture equipment performs pretreatment S10B and carbon dioxide capture treatment S20 in the same manner as the carbon dioxide capture equipment in each of the above embodiments. Pretreatment S10B is performed by the pretreatment device 10B, and carbon dioxide capture treatment S20 is performed by the carbon dioxide capture device 50. The carbon dioxide capture treatment S20 in this embodiment is performed in the same manner as the carbon dioxide capture equipment in each of the above embodiments. First time The pre-treatment S10B in this embodiment is the same as the collection treatment S20. The pre-treatment S10B in this embodiment is different from the pre-treatment S10 in the first embodiment.

[0098] Like pretreatment S10 in the first embodiment, pretreatment S10B in this embodiment also includes an acid gas removal step S11B, a dehumidification step S12, and a regeneration step S13. However, the acid gas removal step S11B in this embodiment includes a first step S11Ba and a second step S11Bb. In the first step S11Ba, the exhaust gas is passed through the acid gas adsorbent 16 (first acid gas adsorbent) packed in the first acid gas adsorbent container 13a to remove the acid gases in the exhaust gas. In the second step S11Bb, the exhaust gas is passed through the acid gas adsorbent 16 (second acid gas adsorbent) packed in the second acid gas adsorbent container 13b to remove the acid gases in the exhaust gas.

[0099] In the dehumidification step S12 in this embodiment, moisture is removed from the gas from which the acid gases have been removed from the acid gas adsorbent container in which the acid gas removal step S11B has been performed, either the first acid gas adsorbent container 13a or the second acid gas adsorbent container 13b, using the moisture adsorbent 17 filled in the moisture adsorbent container 15.

[0100] In the regeneration step S13 of this embodiment, the moisture adsorbent 17 filled in the moisture adsorbent container 15 is regenerated with the off-gas from the carbon dioxide recovery device 50. Furthermore, in the regeneration step S13 of this embodiment, the acid gas adsorbent 16 filled in the acid gas adsorbent container that has been subjected to the acid gas removal step S11B, out of the first acid gas adsorbent container 13a and the second acid gas adsorbent container 13b, is regenerated with the off-gas that has passed through the moisture adsorbent container 15.

[0101] Furthermore, in this embodiment, an adsorbent replacement / switching process S30B is also executed in the pretreatment device 10B. This replacement / switching process S30B is executed by an operator. The replacement / switching process S30B includes a determination step S31B and a replacement / switching step S32B.

[0102] In the determination step S31B, an operator determines whether or not the acid gas adsorbent 16 and the moisture adsorbent 17 satisfy the predetermined replacement / switching conditions.

[0103] In this determination step S31B, for example, a part of the acid gas adsorbent 16 and a part of the moisture adsorbent 17 in the dehumidification tower 11B are sampled, and the sampled adsorbents are analyzed. If the result of this analysis shows that the degree of deterioration of the sampled adsorbent is equal to or greater than a predetermined level, it is determined that the replacement or switching conditions are met.

[0104] In addition, in this determination step S31B, the adsorbent may not be analyzed as described above, and the replacement condition or the switching condition may be determined to be satisfied if the period since the previous adsorbent replacement is equal to or longer than a predetermined period. In addition, in this determination step S31B, the replacement condition or the switching condition may be determined to be satisfied if the cumulative amount of gas that has passed through the replaced adsorbent since the previous adsorbent replacement is equal to or longer than a predetermined amount.

[0105] When the operator determines that the replacement conditions have been met, he replaces the adsorbent that has met the replacement conditions with a new adsorbent. Furthermore, when the operator determines that one of the acid gas adsorbents 16 filled in the first acid gas adsorbent container 13a and the second acid gas adsorbent container 13b has met the switching conditions, he stops the flow of exhaust gas into one of the acid gas adsorbents 16 and passes the acid gas through the other acid gas adsorbent 16 (replacement / switching step S32B). For example, when the operator determines that the acid gas adsorbent 16 filled in the first acid gas adsorbent container 13a has met the switching conditions, the first branch exhaust gas valves 42aa and 42ab are closed and the second branch exhaust gas valves 42ba and 42bb are opened in the replacement / switching step S32B.

[0106] Here, an operator closes the first branch exhaust gas valves 42aa, 42ab and opens the second branch exhaust gas valves 42ba, 42bb. However, the control device may close the first branch exhaust gas valves 42aa, 42ab and open the second branch exhaust gas valves 42ba, 42bb. In this case, the control device executes the determination step S31B and controls the open / close states of the first branch exhaust gas valves 42aa, 42ab and the second branch exhaust gas valves 42ba, 42bb according to the determination result of the determination step S31B.

[0107] As described above, even if the dehumidifying container 12B is composed of three containers, the exhaust gas can be passed through the acidic gas adsorbent 16 and then through the moisture adsorbent 17, so that this embodiment can also achieve the same effects as the above embodiments.

[0108] Furthermore, in this embodiment, when the acid gas adsorbent 16 packed in one of the first acid gas adsorbent container 13a and the second acid gas adsorbent container 13b deteriorates and satisfies the switching condition, the acid gas in the exhaust gas can be adsorbed by the acid gas adsorbent 16 packed in the other container. Therefore, even if the acid gas adsorbent 16 packed in one of the first acid gas adsorbent container 13a and the second acid gas adsorbent container 13b deteriorates, pretreatment S10B in the pretreatment device 10B can be continuously performed.

[0109] "Fourth Embodiment" A fourth embodiment of the carbon dioxide recovery facility will be described with reference to FIGS.

[0110] 7, the carbon dioxide capture system of the present embodiment, like the carbon dioxide capture systems of the above embodiments, includes a pretreatment device 10C and a carbon dioxide capture device 50. The carbon dioxide capture device 50 of the present embodiment is the same as the carbon dioxide capture device 50 of the above embodiments. On the other hand, the pretreatment device 10C of the present embodiment is different from the pretreatment device 10 of the first embodiment.

[0111] A pretreatment device 10C in this embodiment is an apparatus in which a first acidic gas adsorption tower 18a, a second acidic gas adsorption tower 18b, and a switching mechanism 29C are added to the pretreatment device 10 in the first embodiment.

[0112] The first acidic gas adsorption tower 18a and the second acidic gas adsorption tower 18b each include an acidic gas adsorbent 16 capable of adsorbing acidic gases, and a container 19 filled with the acidic gas adsorbent 16. The container 19 of the first acidic gas adsorption tower 18a and the container 19 of the second acidic gas adsorption tower 18b each include a first port 19i through which exhaust gas from the blower 6 can flow in, and a second port 19o through which gas that has passed through the acidic gas adsorbent 16 can flow out.

[0113] The exhaust gas line 20C of this embodiment includes a main exhaust gas line 21, a first branch exhaust gas line 23a, a second branch exhaust gas line 23b, a first primarily treated gas line 24a, a second primarily treated gas line 24b, a combined gas line 25, a first exhaust gas line 22Ca, and a second exhaust gas line 22Cb. One end of the main exhaust gas line 21 is connected to the exhaust gas generation source 1, similar to the one end of the main exhaust gas line 21 in each of the above embodiments. One end of the first branch exhaust gas line 23a and one end of the second branch exhaust gas line 23b are connected to the other end of the main exhaust gas line 21. The other end of the first branch exhaust gas line 23a is connected to the first port 19i of the first acidic gas adsorption tower 18a. The other end of the second branch exhaust gas line 23b is connected to the first port 19i of the second acidic gas adsorption tower 18b. A first branch exhaust gas valve 42a is provided on the first branch exhaust gas line 23a. The second branch exhaust gas line 23b is provided with a second branch exhaust gas valve 42b. One end of the first primarily treated gas line 24a is connected to the second port 19o of the first acidic gas adsorption tower 18a. One end of the second primarily treated gas line 24b is connected to the second port 19o of the second acidic gas adsorption tower 18b. One end of a combined gas line 25 is connected to the other end of the first primarily treated gas line 24a and the other end of the second primarily treated gas line 24b. One end of a first exhaust gas line 22Ca and one end of a second exhaust gas line 22Cb are connected to the other end of the combined gas line 25. The other end of the first exhaust gas line 22Ca is connected to the first port 12i of the first dehumidification tower 11a, as in the first embodiment. The other end of the second exhaust gas line 22Cb is connected to the first port 12i of the second dehumidification tower 11b, as in the first embodiment. The first exhaust gas line 22Ca is provided with a first exhaust gas valve 41a, as in the first embodiment, and the second exhaust gas line 22Cb is provided with a second exhaust gas valve 41b, as in the first embodiment.

[0114] The switching mechanism 29C is configured to be switchable between a first state in which the exhaust gas from the blower 6 can be guided to the first port 19i of the first acidic gas adsorption tower 18a and a second state in which the exhaust gas from the blower 6 can be guided to the first port 19i of the second acidic gas adsorption tower 18b. Specifically, the switching mechanism 29C is configured to have a first branch exhaust gas line 23a, a second branch exhaust gas line 23b, a first branch exhaust gas valve 42a, and a second branch exhaust gas valve 42b.

[0115] Next, the operation of the carbon dioxide recovery facility described above will be described with reference to the flowchart shown in FIG.

[0116] The carbon dioxide capture facility executes pretreatment S10C and carbon dioxide capture treatment S20, similar to the carbon dioxide capture facility in each of the above embodiments. Pretreatment S10C is executed by pretreatment device 10C, and carbon dioxide capture treatment S20 is executed by carbon dioxide capture device 50. The carbon dioxide capture treatment S20 in this embodiment is the same as the carbon dioxide capture treatment S20 in each of the above embodiments. Pretreatment S10C in this embodiment differs from pretreatment S10 in the first embodiment.

[0117] Like the pretreatment S10 in the first embodiment, the pretreatment S10C in this embodiment also includes an acidic gas removal step S11C, a dehumidification step S12, and a regeneration step S13. However, the acidic gas removal step S11C in this embodiment includes a primary acidic gas removal step S11CA and a secondary acidic gas removal step S11CB.

[0118] The primary acidic gas removal step S11CA includes a first step S11CAa and a second step S11CAb. In the first step S11CAa, the exhaust gas is passed through the acidic gas adsorbent 16 (first acidic gas adsorbent) packed in the first acidic gas adsorption tower 18a to remove the acidic gases in the exhaust gas. In the second step S11CAb, the exhaust gas is passed through the acidic gas adsorbent 16 (second acidic gas adsorbent) packed in the second acidic gas adsorption tower 18b to remove the acidic gases in the exhaust gas.

[0119] In the secondary acidic gas removal step S11CB, acidic gases are removed from the gas from the acidic gas adsorption tower in which the primary acidic gas removal step S11CA has been carried out, either in the first acidic gas adsorbent container 13a or the second acidic gas adsorbent container 13b, using the acidic gas adsorbent 16 in the dehumidification tower 11.

[0120] In the dehumidification step S12, moisture is removed from the acid-gas-removed gas, which is a gas from which acid gases have been removed by the acid gas adsorbent 16 in the dehumidification tower 11, by the moisture adsorbent 17 also in the dehumidification tower 11.

[0121] In the regeneration step S13 in this embodiment, the moisture adsorbent 17 filled in the dehumidification tower 11 is regenerated with off-gas from the carbon dioxide capture device 50.

[0122] Furthermore, in this embodiment, an adsorbent replacement / switching process S30C is also executed in the pretreatment device 10C. This replacement / switching process S30C is executed by an operator. This replacement / switching process S30C includes a determination step S31C and a replacement / switching step S32C.

[0123] In the determination step S31C, an operator determines whether or not the acid gas adsorbent 16 and the moisture adsorbent 17 satisfy the predetermined replacement / switching conditions.

[0124] In this determination step S31C, for example, a portion of the acid gas adsorbent 16 in the acid gas adsorption towers 18a and 18b, a portion of the acid gas adsorbent 16 in the dehumidification tower 11, and a portion of the moisture adsorbent 17 are sampled, and the sampled adsorbents are analyzed. If the analysis results show that the degree of deterioration of the sampled adsorbent is equal to or greater than a predetermined level, it is determined that the replacement or switching conditions are met.

[0125] In addition, in this determination step S31C, the adsorbent may not be analyzed as described above, and the replacement condition or the switching condition may be determined to be satisfied if the period since the previous adsorbent replacement is equal to or longer than a predetermined period. In addition, in this determination step S31C, the replacement condition or the switching condition may be determined to be satisfied if the cumulative amount of gas that has passed through the replaced adsorbent since the previous adsorbent replacement is equal to or longer than a predetermined amount.

[0126] When the operator determines that the replacement conditions have been met, he replaces the adsorbent that has met the replacement conditions with a new adsorbent. Furthermore, when the operator determines that one of the acid gas adsorbents 16 filled in the first acid gas adsorption tower 18a and the second acid gas adsorption tower 18b has met the switching conditions, he stops the flow of exhaust gas into one of the acid gas adsorbents 16 and passes the acid gas through the other acid gas adsorbent 16 (replacement / switching step S32B). For example, when the acid gas adsorbent 16 filled in the first acid gas adsorption tower 18a and the second acid gas adsorbent 16 have met the switching conditions, tower 18b If it is determined that the acidic gas adsorbent 16 filled in the first acidic gas adsorption tower 18a satisfies the switching conditions, the replacement / switching process S32B closes the first branch exhaust gas valve 42a and opens the second branch exhaust gas valve 42b.

[0127] Here, an operator closes the first branch exhaust gas valve 42a and opens the second branch exhaust gas valve 42b. However, the control device may close the first branch exhaust gas valve 42a and open the second branch exhaust gas valve 42b. In this case, the control device executes the determination step S31C and controls the open / close states of the first branch exhaust gas valve 42a and the second branch exhaust gas valve 42b according to the determination result of the determination step S31C.

[0128] As described above, in this embodiment, as in the above embodiments, the exhaust gas can be passed through the acid gas adsorbent 16 and then through the moisture adsorbent 17, so that the same effects as in the above embodiments can be obtained in this embodiment.

[0129] Furthermore, in this embodiment, if the acid gas adsorbent 16 packed in one of the first acid gas adsorption tower 18a and the second acid gas adsorption tower 18b deteriorates and satisfies the switching condition, the acid gas in the exhaust gas can be adsorbed by the acid gas adsorbent 16 packed in the other adsorption tower. Therefore, even if the acid gas adsorbent 16 packed in one of the first acid gas adsorption tower 18a and the second acid gas adsorption tower 18b deteriorates, pretreatment S10C in the pretreatment device 10C can be continuously performed.

[0130] Although the embodiments of the present disclosure have been described in detail above, the present disclosure is not limited to the above embodiments. Various additions, modifications, substitutions, partial deletions, etc. are possible within the scope of the conceptual idea and spirit of the present invention derived from the content defined in the claims and their equivalents.

[0131] "Addendum" The pre-processing device in the above embodiment can be understood as follows, for example.

[0132] (1) The pretreatment device in the first aspect comprises: Each pretreatment device 10, 10A, 10B, 10C is capable of removing moisture from exhaust gas containing moisture, carbon dioxide, and acidic gases before treatment in a carbon dioxide capture device 50. The pretreatment device 10, 10A, 10B, 10C includes a dehumidification tower 11, 11A, 11B capable of removing moisture from the exhaust gas, and a blower 6 capable of sending the exhaust gas into the dehumidification tower 11, 11A, 11B. The dehumidification tower 11, 11A, 11B includes a moisture adsorbent 17 capable of adsorbing moisture, an acidic gas adsorbent 16 capable of adsorbing acidic gases, and a dehumidification container 12, 12A, 12B filled with the moisture adsorbent 17 and the acidic gas adsorbent 16. The dehumidification container 12, 12A, 12B includes a first port 12i through which the exhaust gas from the blower 6 can flow in, and a second port 12o through which gas that has passed through the moisture adsorbent 17 and the acidic gas adsorbent 16 can flow out as pretreated gas. The acid gas adsorbent 16 is filled in the dehumidifying container 12, 12A, 12B on the side of the first port 12i, and the moisture adsorbent 17 is filled in the dehumidifying container 12, 12A, 12B on the side of the second port 12o relative to the acid gas adsorbent 16. The moisture adsorbent 17 is an adsorbent containing alumina. The acid gas adsorbent 16 is an adsorbent containing silica but not alumina, or an adsorbent containing silica and alumina and having a (Si / Al) molar ratio > 2.5.

[0133] Representative moisture adsorbents include zeolite and silica gel. Silica gel is resistant to acidic gases. Therefore, even if silica gel is used as an adsorbent for adsorbing moisture from exhaust gases containing moisture and acidic gases, the dehumidifying performance of the silica gel does not decrease significantly. On the other hand, when an adsorbent containing alumina, such as zeolite, is used as an adsorbent for adsorbing moisture from exhaust gases containing moisture and acidic gases, the alumina binds with the acidic gases, thereby decreasing the dehumidifying performance of the adsorbent. In other words, adsorbents containing alumina have lower resistance to acidic gases than silica gel. As described above, from the viewpoint of resistance to acidic gases, adsorbents with a high silica content relative to the alumina content are preferred.

[0134] On the other hand, adsorbents containing alumina, such as zeolite, can lower the dew point of exhaust gas compared to silica gel. In other words, adsorbents containing alumina can lower the moisture concentration in exhaust gas compared to silica gel. As described above, from the perspective of lowering the dew point of gas, adsorbents with a relatively high alumina content relative to the silica content are preferred.

[0135] In this embodiment, from the viewpoint of lowering the dew point of the gas sent to the carbon dioxide capture unit 50, an adsorbent containing alumina is used as the moisture adsorbent 17.

[0136] However, since the moisture adsorbent 17 containing alumina has low resistance to acidic gases, in this embodiment, the exhaust gas is passed through the acidic gas adsorbent 16 to remove most of the acidic gases in the exhaust gas, and then the exhaust gas is passed through the moisture adsorbent 17. Thus, the acidic gas adsorbent 16 serves to protect the moisture adsorbent 17 used in this embodiment by adsorbing acidic gases.

[0137] As described above, in this embodiment, an adsorbent containing alumina is used as the moisture adsorbent 17, so that the dew point of the gas sent to the carbon dioxide capture device 50 can be reduced. As described above, this adsorbent containing alumina has low resistance to acidic gases. However, in this embodiment, as described above, the exhaust gas is passed through the acidic gas adsorbent 16 to remove most of the acidic gases in the exhaust gas, and then the gas is passed through the moisture adsorbent 17, so that the moisture adsorption performance of the moisture adsorbent 17 can be maintained for a long period of time.

[0138] (2) The pretreatment device in the second aspect is In the pretreatment devices 10A and 10B of the first embodiment, the dehumidifying containers 12A and 12B include acid gas adsorbent containers 13, 13a, and 13b filled with the acid gas adsorbent 16, and moisture adsorbent containers 15 filled with the moisture adsorbent 17. The acid gas adsorbent containers 13, 13a, and 13b include a first port 13i through which the exhaust gas from the blower 6 can flow in and a second port 13o through which gas that has passed through the acid gas adsorbent 16 can flow out as gas from which acid gases have been removed. The moisture adsorbent container 15 includes a first port 15i through which the gas from which acid gases have been removed can flow in and a second port 15o through which gas that has passed through the moisture adsorbent 17 can flow out. The first port 13i of the acid gas adsorbent container 13 corresponds to the first port 12i of the dehumidifying containers 12A and 12B. The second port 15o of the moisture adsorbent container 15 is the second port 12o of the dehumidifying containers 12A and 12B.

[0139] (3) The pretreatment device in the third aspect is The pretreatment device 10B of the second embodiment further includes a switching mechanism 29B. The acid gas adsorbent containers 13a, 13b include a first acid gas adsorbent container 13a filled with the acid gas adsorbent 16 and a second acid gas adsorbent container 13b filled with the acid gas adsorbent 16. The first acid gas adsorbent container 13a and the second acid gas adsorbent container 13b each include a first port 12i that functions as the first port 12i of the acid gas adsorbent containers 13a, 13b, and a second port 12o that functions as the second port 12o of the acid gas adsorbent containers 13a, 13b. The switching mechanism 29B is configured to be switchable between a first state in which the exhaust gas from the blower 6 can be guided to the first port 13i of the first acid gas adsorbent container 13a, and a second state in which the exhaust gas from the blower 6 can be guided to the first port 13i of the second acid gas adsorbent container 13b. The gas flowing out from the second port 13o of the first acidic gas adsorbent container 13a and the gas flowing out from the second port 13o of the second acidic gas adsorbent container 13b are configured to be able to flow into the moisture adsorbent container 15 through the first port 15i of the moisture adsorbent container 15.

[0140] In this embodiment, if the acid gas adsorbent 16 packed in one of the first acid gas adsorbent container 13a and the second acid gas adsorbent container 13b deteriorates, the acid gas in the exhaust gas can be adsorbed by the acid gas adsorbent 16 packed in the other container. Therefore, even if the acid gas adsorbent 16 packed in one of the first acid gas adsorbent container 13a and the second acid gas adsorbent container 13b deteriorates, pretreatment S10B in the pretreatment device 10B can be continuously performed.

[0141] (4) The pretreatment device in the fourth aspect is The pretreatment device 10C of the first embodiment further includes a first acid gas adsorption tower 18a, a second acid gas adsorption tower 18b, and a switching mechanism 29C. The first acid gas adsorption tower 18a and the second acid gas adsorption tower 18b each include an acid gas adsorbent 16 capable of adsorbing acid gases and a container 19 filled with the acid gas adsorbent 16. The container 19 of the first acid gas adsorption tower 18a and the container 19 of the second acid gas adsorption tower 18b each include a first port 19i through which the exhaust gas from the blower 6 can flow in and a second port 19o through which gas that has passed through the acid gas adsorbent 16 can flow out. The switching mechanism 29C is configured to be switchable between a first state in which the exhaust gas from the blower 6 can be introduced to the first port 19i of the first acid gas adsorption tower 18a and a second state in which the exhaust gas from the blower 6 can be introduced to the first port 19i of the second acid gas adsorption tower 18b. The gas flowing out from the second port 19o of the first acidic gas adsorption tower 18a and the gas flowing out from the second port 19o of the second acidic gas adsorption tower 18b are configured to be able to flow into the dehumidification tower 11 from the first port 12i of the dehumidification tower 11.

[0142] In this embodiment, if the acid gas adsorbent 16 packed in one of the first acid gas adsorption tower 18a and the second acid gas adsorption tower 18b deteriorates, the acid gas in the exhaust gas can be adsorbed by the acid gas adsorbent 16 packed in the other adsorption tower. Therefore, even if the acid gas adsorbent 16 packed in one of the first acid gas adsorption tower 18a and the second acid gas adsorption tower 18b deteriorates, pretreatment S10C in the pretreatment device 10C can be continuously performed.

[0143] (5) The pretreatment device in the fifth aspect is In the pretreatment devices 10, 10A, 10B, and 10C according to any one of the first to fourth aspects, the moisture adsorbent 17 is activated alumina or zeolite.

[0144] (6) The pretreatment device in the sixth aspect is In the pretreatment devices 10, 10A, 10B, and 10C according to any one of the first to fourth embodiments, the moisture adsorbent 17 is zeolite having a (Si / Al) molar ratio of less than 2.5.

[0145] (7) In the seventh aspect, the pretreatment device comprises: In the pretreatment devices 10, 10A, 10B, and 10C according to any one of the first to sixth aspects, the acidic gas adsorbent 16 is silica gel or high-silica zeolite.

[0146] The carbon dioxide recovery facility in the above embodiment can be understood, for example, as follows. (8) In the eighth aspect, the carbon dioxide recovery equipment is The present invention includes the pretreatment device 10, 10A, 10B, 10C according to any one of the first to seventh aspects, and the carbon dioxide capture device 50. The carbon dioxide capture device 50 includes a carbon dioxide adsorption tower 51 into which the pretreated gas can flow and which is filled with a carbon dioxide adsorbent 53 capable of adsorbing carbon dioxide in the pretreated gas, and an aspirator 55 which draws a vacuum inside the carbon dioxide adsorption tower 51.

[0147] In the pretreatment devices 10, 10A, 10B, and 10C of this embodiment, the dew point of the gas sent to the carbon dioxide recovery device 50 can be lowered; in other words, the moisture concentration in this gas can be reduced. This allows carbon dioxide to be efficiently adsorbed by the carbon dioxide adsorbent 53 in the carbon dioxide adsorption tower 51. The carbon dioxide adsorbed by the carbon dioxide adsorbent 53 is recovered by vacuum suctioning the carbon dioxide adsorption tower 51 with an aspirator 55.

[0148] The pre-processing method in the above embodiment can be understood, for example, as follows. (9) In the ninth aspect, the pretreatment method comprises: In a pretreatment method for removing moisture from exhaust gas containing moisture, carbon dioxide, and acidic gases prior to the carbon dioxide capture treatment S20, the method includes acid gas removal steps S11, S11B, and S11C, in which the exhaust gas is passed through an acid gas adsorbent 16 capable of adsorbing acidic gases to remove the acidic gases from the exhaust gas, and a dehumidification step S12, in which the exhaust gas from which acid gases have been removed is passed through a moisture adsorbent 17 capable of adsorbing moisture to remove moisture from the acid gas-removed gas, and the pretreated gas from which acid gases have been removed after moisture removal is subjected to the carbon dioxide capture treatment S20. The acid gas adsorbent 16 is an adsorbent containing silica but not alumina, or an adsorbent containing silica and alumina with a (Si / Al) molar ratio > 2.5. The moisture adsorbent 17 is an adsorbent containing alumina.

[0149] In this embodiment, similar to the pretreatment devices 10, 10A, 10B, and 10C in the first embodiment, the dew point of the gas subjected to the carbon dioxide recovery treatment S20 can be reduced, and the moisture adsorption performance of the moisture adsorbent 17 used in the pretreatment devices S10, S10B, and S10C can be maintained for a long period of time.

[0150] (10) In the tenth aspect, the pretreatment method comprises: In the pretreatment method of the ninth aspect, the acid gas removal step S11B includes a first step S11Ba in which the exhaust gas is passed through a first acid gas adsorbent 16 capable of adsorbing acid gases to remove the acid gases in the exhaust gas, and a second step S11Bb in which the exhaust gas is passed through a second acid gas adsorbent 16 capable of adsorbing acid gases to remove the acid gases in the exhaust gas. The pretreatment method further includes a determination step S31B in which it is determined whether either the first acid gas adsorbent 16 or the second acid gas adsorbent 16 has deteriorated, and a switching step 32B in which, if it is determined in the determination step S31B that one of the acid gas adsorbents 16 has deteriorated, of the first step S11Ba or the second step S11Bb is terminated, in which the exhaust gas is passed through the one acid gas adsorbent 16, and the other step is executed.

[0151] In this embodiment, if one of the first acidic gas adsorbent 16 and the second acidic gas adsorbent 16 deteriorates, the other acidic gas adsorbent 16 can adsorb the acidic gases in the exhaust gas, so that pretreatment S10B can be continued.

[0152] (11) In the eleventh aspect, the pretreatment method comprises: In the pretreatment method of the ninth or tenth aspect, a determination step S31, S31B, or S32C is further performed to determine whether the acidic gas adsorbent 16 has deteriorated, and if it is determined in the determination step S31, S31B, or S31C that the acidic gas adsorbent 16 has deteriorated, an exchange step S32, S32B, or S32C is further performed to replace the acidic gas adsorbent 16 with a new acidic gas adsorbent 16.

[0153] (12) In the twelfth aspect, the pretreatment method comprises: In the pretreatment method according to any one of the ninth to eleventh aspects, the moisture adsorbent 17 is activated alumina or zeolite.

[0154] (13) In the thirteenth aspect, the pretreatment method comprises: In the pretreatment method according to any one of the ninth to eleventh aspects, the moisture adsorbent 17 is a zeolite having a (Si / Al) molar ratio of less than 2.5.

[0155] (14) In the fourteenth aspect, the pretreatment method comprises: In the pretreatment method according to any one of the ninth to thirteenth aspects, the acidic gas adsorbent 16 is silica gel or high-silica zeolite.

[0156] The carbon dioxide recovery method in the above embodiment can be understood, for example, as follows. (15) In a fifteenth aspect, the carbon dioxide recovery method comprises: The pretreatment method according to any one of the ninth to fourteenth aspects is carried out, and the carbon dioxide recovery treatment S20 is carried out. The carbon dioxide recovery treatment S20 includes a carbon dioxide adsorption step S21 in which the pretreated gas is passed through a carbon dioxide adsorbent 53 capable of adsorbing carbon dioxide, so that the carbon dioxide in the pretreated gas is adsorbed by the carbon dioxide adsorbent 53, and a carbon dioxide desorption step S22 in which the carbon dioxide is desorbed from the carbon dioxide adsorbent 53 and the carbon dioxide is recovered.

[0157] In this embodiment, the dew point of the gas subjected to the carbon dioxide recovery treatment S20 can be lowered, in other words, the moisture concentration in this gas can be reduced. Therefore, carbon dioxide can be efficiently adsorbed by the carbon dioxide adsorbent 53 used in the carbon dioxide adsorption step S21. The carbon dioxide adsorbed by the carbon dioxide adsorbent 53 is recovered by executing the carbon dioxide desorption step S22. [Explanation of symbols]

[0158] 1: Exhaust gas source 6: Blower 7: Dehumidifying vacuum pump 10, 10A, 10B, 10C: Pre-treatment device 11,11A,11B:Dehumidification tower 11a, 11Aa, 11Ba: First dehumidification tower 11b,11Ab,11Bb:Second dehumidification tower 12,12A,12B: Dehumidification container 12i:First mouth 12o:Second mouth 13: Acid gas adsorbent container 13a: First acid gas adsorbent vessel 13b: Second acid gas adsorbent vessel 13i:First mouth 13o:Second mouth 15: Moisture absorbent container 15i:First mouth 15o:Second mouth 16: Acid gas adsorbent 17: Moisture absorbent 18a: First acid gas adsorption tower 18b: Second acid gas adsorption tower 19: Container 19i:First mouth 19o:Second mouth 20, 20B, 20C: Exhaust gas line 21: Main exhaust gas line 22a, 22Ba, 22Ca: First exhaust gas line 22b, 22Bb, 22Cb: Second exhaust gas line 23a, 23aa, 23ab: First branch exhaust gas line 23b, 23ba, 23bb: Second branch exhaust gas line 24a: First primary treated gas line 24b: Second primary treated gas line 25: Confluent gas line 26a: First acid gas removed gas line 26aa: First a acid gas removed gas line 26ab: First b acid gas removed gas line 26b: Secondary acid gas removed gas line 26ba: Second A acid gas removed gas line 26bb: Second b acid gas removed gas line 29B, 29C: Switching mechanism 30: Pre-treated gas line 31a: First pre-treated gas line on the dehumidification side 31b: Dehumidification side second pre-treated gas line 32: Main pre-treated gas line 33a: First pre-treated gas line on the recovery side 33b: Recovery side second pre-treated gas line 33c: Recovery side third pre-treated gas line 34: Moisture-rich gas line 35a: First moisture-rich gas line 35b: Second moisture-rich gas line 36: Main moisture-rich gas line 37: Offgas line 38a: Recovery side first off-gas line 38b: Recovery side second off-gas line 38c: Recovery side third off-gas line 38m: Main off-gas line 39a: Dehumidification side first off-gas line 39b: Dehumidification side second off-gas line 41a: First exhaust gas valve 41b: Second exhaust gas valve 42a, 42aa, 42ab: First branch exhaust gas valve 42b, 42ba, 42bb: Second branch exhaust gas valve 43a: Dehumidification side first pre-treated gas valve 43b: Dehumidification side second pre-treated gas valve 44a: First moisture-rich gas valve 44b: Second moisture-rich gas valve 45a: Dehumidification side first off-gas valve 45b: Dehumidification side second off-gas valve 50: Carbon dioxide capture device 51: Carbon dioxide adsorption tower 51a: First carbon dioxide adsorption tower 51b: Second carbon dioxide adsorption tower 51c: Third carbon dioxide adsorption tower 52: Container 52i:First mouth 52o:Second mouth 53: Carbon dioxide adsorbent 55: Suction machine 56a: Recovery side first pre-treated gas valve 56b: Recovery side second pre-treated gas valve 56c: Recovery side third pre-treated gas valve 57a: First suction valve 57b: Second suction valve 57c: Third suction valve 58a: Recovery side first off-gas valve 58b: Recovery side second off-gas valve 58c: Recovery side third off-gas valve 63: Recovery tank 65: Suction line 66a: First suction line 66b: Second suction line 66c: Third suction line 67: Main suction line 68: Discharge line

Claims

1. A pretreatment device capable of removing moisture from exhaust gas containing moisture, carbon dioxide, and acidic gases before treatment in a carbon dioxide recovery device, a dehumidification tower capable of removing moisture from the exhaust gas; a blower capable of sending the exhaust gas into the dehumidification tower; a first acid gas adsorption tower; a second acid gas adsorption tower; A switching mechanism; Equipped with the dehumidifying tower includes a moisture adsorbent capable of adsorbing moisture, an acidic gas adsorbent capable of adsorbing acidic gas, and a dehumidifying container filled with the moisture adsorbent and the acidic gas adsorbent; the dehumidifying container has a first port through which the exhaust gas from the blower can flow in and a second port through which gas that has passed through the moisture adsorbent and the acidic gas adsorbent can flow out as a pretreated gas, the acid gas adsorbent is filled in the dehumidifying container on the side of the first port, and the moisture adsorbent is filled in the dehumidifying container on the side of the second port relative to the acid gas adsorbent, the moisture adsorbent is an adsorbent containing alumina, The acid gas adsorbent is an adsorbent containing silica but not containing alumina, or an adsorbent containing silica and alumina, and having a (Si / Al) molar ratio of >2.5; each of the first acidic gas adsorption tower and the second acidic gas adsorption tower includes an acidic gas adsorbent capable of adsorbing acid gases and a container filled with the acidic gas adsorbent; the vessel of the first acidic gas adsorption tower and the vessel of the second acidic gas adsorption tower each have a first port through which the exhaust gas from the blower can flow in and a second port through which gas that has passed through the acidic gas adsorbent can flow out; the switching mechanism is configured to be switchable between a first state in which the exhaust gas from the blower can be guided to the first port of the first acidic gas adsorption tower and a second state in which the exhaust gas from the blower can be guided to the first port of the second acidic gas adsorption tower; the gas flowing out from the second port of the first acidic gas adsorption tower and the gas flowing out from the second port of the second acidic gas adsorption tower are configured to be able to flow into the dehumidification tower from the first port of the dehumidification tower. Pretreatment device.

2. In the pretreatment device according to claim 1, The moisture adsorbent is activated alumina or zeolite. Pretreatment device.

3. In the pretreatment device according to claim 1 or 2, The moisture adsorbent is a zeolite having a (Si / Al) molar ratio of less than 2.

5. Pretreatment device.

4. 4. The pretreatment device according to claim 1, The acid gas adsorbent is silica gel or high-silica zeolite. Pretreatment device.

5. A pretreatment device according to any one of claims 1 to 4; the carbon dioxide capture device; Equipped with The carbon dioxide capture device a carbon dioxide adsorption tower into which the pretreated gas can flow and which is filled with a carbon dioxide adsorbent capable of adsorbing carbon dioxide in the pretreated gas; a suction machine that suctions the inside of the carbon dioxide adsorption tower; Equipped with Carbon dioxide capture facility.

6. A pretreatment method for removing moisture from an exhaust gas containing moisture, carbon dioxide, and acid gases before a carbon dioxide recovery treatment, comprising: an acid gas removal step of passing the exhaust gas through an acid gas adsorbent capable of adsorbing acid gases to remove the acid gases in the exhaust gas; a dehumidification step of passing the acid-gas-removed gas, which is the exhaust gas that has been subjected to the acid-gas removal step, through a moisture adsorbent capable of adsorbing moisture to remove moisture from the acid-gas-removed gas, and subjecting the pretreated gas, which is the acid-gas-removed gas after moisture removal, to the carbon dioxide recovery treatment; Run The acid gas adsorbent is an adsorbent containing silica but not containing alumina, or an adsorbent containing silica and alumina, and having a (Si / Al) molar ratio of >2.5; the moisture adsorbent is an adsorbent containing alumina, The acid gas removal step includes a primary acid gas removal step and a secondary acid gas removal step, the primary acid gas removal step includes a first step of passing the exhaust gas through a first acid gas adsorbent capable of adsorbing acid gases to remove the acid gases in the exhaust gas, and a second step of passing the exhaust gas through a second acid gas adsorbent capable of adsorbing acid gases to remove the acid gases in the exhaust gas, a determining step of determining whether or not one of the first acidic gas adsorbent and the second acidic gas adsorbent has deteriorated; a switching step of terminating one of the first and second steps in which the exhaust gas is passed through the one of the acid gas adsorbents and executing the other step when it is determined in the determination step that the one of the acid gas adsorbents has deteriorated; Further execute In the secondary acid gas removal step, acid gases are removed from the exhaust gas after the primary acid gas removal step. Pretreatment methods.

7. In the pretreatment method according to claim 6, The moisture adsorbent is activated alumina or zeolite. Pretreatment methods.

8. In the pretreatment method according to claim 6 or 7, The moisture adsorbent is a zeolite having a (Si / Al) molar ratio of less than 2.

5. Pretreatment methods.

9. The pretreatment method according to any one of claims 6 to 8, The acid gas adsorbent is silica gel or high-silica zeolite. Pretreatment methods.

10. Carrying out the pretreatment method according to any one of claims 6 to 9, Carrying out the carbon dioxide capture process; The carbon dioxide recovery process includes: a carbon dioxide adsorption step of passing the pretreated gas through a carbon dioxide adsorbent capable of adsorbing carbon dioxide, thereby adsorbing the carbon dioxide in the pretreated gas onto the carbon dioxide adsorbent; a carbon dioxide desorption step of desorbing the carbon dioxide from the carbon dioxide adsorbent and recovering the carbon dioxide; Including, Carbon dioxide capture methods.

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