Acid gas adsorption device

Abstract

The invention provides an acid gas adsorption device capable of improving the adsorption efficiency of acid gas. An acid gas adsorption device according to an embodiment of the present invention is provided with: an acid gas adsorption unit through which a fluid can pass in a predetermined direction; and a single case. The acid gas adsorption part contains an acid gas adsorption material capable of adsorbing an acid gas. The acid gas adsorption part comprises a first adsorption part; and a second adsorption part disposed downstream of the first adsorption part in the direction in which the fluid passes. The first adsorption part includes a first acid gas adsorption material that has a relatively small adsorption capacity for adsorbing acid gas and a relatively large adsorption capacity for acid gas. The second adsorption part contains a second acid gas adsorption material having a relatively large adsorption capacity for adsorbing the acid gas and a relatively small adsorption capacity for the acid gas. The housing accommodates the first adsorption part and the second adsorption part together.

Description

Technical Field The invention relates to an acid gas adsorption device. Background Art In recent years, efforts have been made to separate and recover acid gases contained in the atmosphere in order to reduce the environmental load. As such acid gases, carbon dioxide (hereinafter sometimes referred to as CO2) which causes global warming can be mainly cited. As a representative example of the above efforts, the carbon dioxide capture, utilization and storage (CCUS) cycle is known. As a carbon dioxide adsorption device used in the separation and recovery of such carbon dioxide, a gas separation unit having a carbon dioxide adsorption portion with a granular structure has been proposed (for example, see patent document 1). In such a carbon dioxide adsorption device, the carbon dioxide adsorbent material adsorbs CO2 at a prescribed adsorption temperature and desorbs CO2 at a desorption temperature exceeding the adsorption temperature. In such a carbon dioxide adsorption device, it is desired to improve the adsorption efficiency of CO2. Prior art literature Patent Literature Patent Document 1: International Publication No. 2014 / 170184 Summary of the invention A main object of the present invention is to provide an acid gas adsorption device capable of improving the adsorption efficiency of acid gases.

[0001] The acid gas adsorption device according to the embodiment of the present invention is provided with an acid gas adsorption section through which a fluid can pass in a predetermined direction. The acid gas adsorption section includes an acid gas adsorption material capable of adsorbing acid gas. The acid gas adsorption section includes: a first adsorption section; and a second adsorption section arranged downstream of the first adsorption section in the direction in which the fluid passes. The first adsorption section includes a first acid gas adsorption material having a relatively small adsorption force for adsorbing acid gas and a relatively large adsorption capacity for acid gas. The second adsorption section includes a second acid gas adsorption material having a relatively large adsorption force for adsorbing acid gas and a relatively small adsorption capacity for acid gas.

[0002] In the acid gas adsorption device described in [1] above, the acid gas may be carbon dioxide.

[0003] In the acid gas adsorption device described in [1] or [2] above, the equilibrium acid gas concentration of the first acid gas adsorption material may exceed 100 ppm, and the equilibrium acid gas concentration of the second acid gas adsorption material may be less than 100 ppm.

[0004] In the acidic gas adsorbent device described in [3] above, the first acidic gas adsorbent may contain tertiary amino groups, and the second acidic gas adsorbent may contain primary amino groups and / or secondary amino groups.

[0005] In the acid gas adsorption device described in any one of [1] to [4] above, the first adsorption section may be divided into a plurality of parts in a direction orthogonal to a passing direction of the fluid.

[0006] In the acid gas adsorption device described in any one of [1] to [4] above, the second adsorption section may be divided into a plurality of parts in a direction orthogonal to a passing direction of the fluid.

[0007] The acid gas adsorption device described in any one of [1] to [6] may further include a housing. The housing may accommodate the first adsorption unit and the second adsorption unit together. Effects of the Invention According to the embodiment of the present invention, an acid gas adsorption device capable of improving the adsorption efficiency of acid gas can be realized. BRIEF DESCRIPTION OF THE DRAWINGS Figure 1 This is a schematic configuration diagram of an acid gas adsorption device according to one embodiment of the present invention. Figure 2 This is a schematic configuration diagram of an acid gas adsorption device according to another embodiment of the present invention. Figure 3 This is a schematic configuration diagram of an acid gas adsorption device according to still another embodiment of the present invention. Figure 4 This is a schematic configuration diagram of an acid gas adsorption device according to still another embodiment of the present invention. Figure 5 This is a schematic configuration diagram of an acid gas adsorption device according to still another embodiment of the present invention. Figure 6 This is a schematic configuration diagram of an acid gas adsorption device according to still another embodiment of the present invention. Figure 7 This is a schematic configuration diagram of an acid gas adsorption device according to still another embodiment of the present invention. Figure 8 yes Figure 6 A schematic diagram of an implementation of the first block in FIG. Fig. 9 yes Figure 6 A schematic three-dimensional diagram of another embodiment of the first block in FIG. Fig.10 yes Fig. 9 Central cross-section of the first block in FIG. DETAILED DESCRIPTION Hereinafter, embodiments of the present invention will be described with reference to the accompanying drawings, but the present invention is not limited to these embodiments. In addition, the accompanying drawings make the description clearer, and therefore, the width, thickness, shape, etc. of each part are sometimes schematically shown compared to the embodiments, but this is only an example and does not limit the interpretation of the present invention. A. Overview of Acid Gas Adsorption Device Figure 1 This is a schematic configuration diagram of an acid gas adsorption device according to one embodiment of the present invention. The acid gas adsorption device 100 shown in the figure is provided with an acid gas adsorption section 1 through which a fluid can pass in a predetermined direction. The acid gas adsorption section 1 includes an acid gas adsorption material that can adsorb acid gas. The acid gas adsorption section 1 includes a first adsorption section 11 and a second adsorption section 12 that is arranged on the downstream side of the first adsorption section 11 in the direction in which the fluid passes. The first adsorption section 11 includes a first acid gas adsorption material that has a relatively small adsorption force for adsorbing acid gas and a relatively large adsorption capacity for acid gas. The second adsorption section 12 includes a second acid gas adsorption material that has a relatively large adsorption force for adsorbing acid gas and a relatively small adsorption capacity for acid gas. In other words, the acid gas adsorption force of the first acid gas adsorption material is smaller than the acid gas adsorption force of the second acid gas adsorption material, and the acid gas adsorption capacity of the first acid gas adsorption material is larger than the acid gas adsorption capacity of the second acid gas adsorption material. In the acid gas adsorption device, a fluid containing acid gas is supplied to the acid gas adsorption section, and the acid gas adsorption material adsorbs the acid gas. Therefore, the concentration of the acid gas in the fluid decreases as it moves toward the downstream side in the passing direction of the fluid. When the entire acid gas adsorption section includes the same acid gas adsorption material, the concentration of the acid gas is relatively high in the upstream side portion of the acid gas adsorption section, so the acid gas adsorption material can adsorb the acid gas, while on the other hand, the concentration of the acid gas is relatively low in the downstream side portion of the acid gas adsorption section, so the acid gas adsorption material may not be able to fully adsorb the acid gas. In contrast, according to one embodiment of the present invention, the first adsorption section located on the upstream side in the passing direction of the fluid includes the first acid gas adsorption material having a larger acid gas adsorption capacity than the second acid gas adsorption material, and therefore, the first acid gas adsorption material can sufficiently adsorb the acid gas from the fluid having a relatively high acid gas concentration. In addition, the second adsorption section located on the downstream side in the passing direction of the fluid includes the second acid gas adsorption material having a larger adsorption force for adsorbing the acid gas than the first acid gas adsorption material, and therefore, even if the concentration of the acid gas in the fluid having passed through the first adsorption section is relatively low, the second acid gas adsorption material can stably adsorb the acid gas from the fluid. Therefore, compared with a case where the entire acid gas adsorption section includes the same acid gas adsorption material, the adsorption performance of the entire acid gas adsorption device can be improved. Regarding the acidic gas that is the adsorption object of the acidic gas adsorption device, for example, carbon dioxide (CO2), hydrogen sulfide, sulfur dioxide, nitrogen dioxide, dimethyl sulfide (DMS), hydrogen chloride, etc. can be cited. In one embodiment, the acidic gas is carbon dioxide (CO2), and the fluid is a CO2-containing gas. The CO2-containing gas contains nitrogen in addition to CO2. The CO2-containing gas is representatively air (atmosphere). The CO2 concentration in the CO2-containing gas before being supplied to the acidic gas adsorption device is, for example, 100 ppm (volume basis) or more and 2 volume % or less. Hereinafter, a case where the acid gas is carbon dioxide (CO 2 ) will be described in detail. The CO2 adsorption capacity (hereinafter referred to as CO2 adsorption capacity) of the first acidic gas adsorbent is larger than the CO2 adsorption capacity of the second acidic gas adsorbent. The CO2 adsorption force (hereinafter referred to as CO2 adsorption force) of the first acidic gas adsorbent is smaller than the CO2 adsorption force of the second acidic gas adsorbent. The CO2 adsorption capacity of the acid gas adsorbent material is: the mass of CO2 that can be adsorbed by every 1 kg of the acid gas adsorbent material (when the acid gas adsorbent material is supported on a porous carrier, the total of the acid gas adsorbent material and the porous carrier is 1 kg) under the conditions of 25°C, 50% RH, and CO2 partial pressure of 15 kPa (the same below). The CO2 adsorption capacity of the first acidic gas adsorbent is, for example, 1.5 mol / kg-adsorbent or more, preferably 2.0 mol / kg-adsorbent or more, and more preferably 2.5 mol / kg-adsorbent or more. The CO2 adsorption capacity can be measured by, for example, the method described in Document 3-2-1 of the Second 2015 Carbon Dioxide Recovery and Storage Field Evaluation Seminar (2) (the same applies hereinafter). The CO2 adsorption capacity of the first acid gas adsorbent can be evaluated based on the equilibrium acid gas concentration (equilibrium CO2 concentration). The CO2 adsorption capacity of the acid gas adsorbent is weaker as the equilibrium acid gas concentration (equilibrium CO2 concentration) is higher, and stronger as the equilibrium acid gas concentration (equilibrium CO2 concentration) is lower. The equilibrium acid gas concentration (equilibrium CO2 concentration) of the first acid gas adsorbent is, for example, more than 100 ppm, preferably more than 200 ppm, more preferably more than 300 ppm, and is, for example, 500 ppm or less. The equilibrium acid gas concentration can be measured as follows: For example, in a dryer sealed with an atmosphere at 25°C and 50% RH, an acid gas adsorbent having an adsorption capacity far exceeding that of the acid gas contained in the dryer is sealed, and the acid gas concentration in the dryer after 4 hours is quantitatively analyzed using an infrared spectrometer to measure the equilibrium acid gas concentration (the same applies hereinafter). Even if the CO2 adsorption capacity of the first acid gas adsorbent is below the above upper limit, in the case of a relatively high CO2 concentration (when the CO2 concentration exceeds the lower limit of the first acid gas adsorbent reaching the equilibrium acid gas concentration (representatively 100 ppm)), the first acid gas adsorbent can adsorb a relatively large amount of CO2 (above the above lower limit of the CO2 adsorption capacity). In addition, typically, as the CO2 adsorption capacity of the acid gas adsorbent increases, the energy required to desorb CO2 from the acid gas adsorbent increases. Therefore, if the CO2 adsorption capacity of the first acid gas adsorbent is below the above upper limit, energy saving in the desorption process described later can be achieved. The equilibrium acid gas concentration (equilibrium CO 2 concentration) of the second acid gas adsorbent is, for example, 100 ppm or less, preferably 75 ppm or less, more preferably 50 ppm or less, and, for example, 10 ppm or more. The CO2 adsorption capacity of the second acidic gas adsorbent is, for example, less than 2.0 mol / kg-adsorbent, preferably less than 1.5 mol / kg-adsorbent, more preferably less than 1.0 mol / kg-adsorbent, and for example, more than 0.5 mol / kg-adsorbent. If the CO2 adsorption capacity of the second acidic gas adsorbent is above the lower limit, the second acidic gas adsorbent can stably adsorb CO2 even when the CO2 concentration is relatively low (when the CO2 concentration is below the lower limit (representatively 100 ppm) of the acidic gas concentration at which the first acidic gas adsorbent reaches equilibrium). In addition, even if the CO2 adsorption capacity of the second acidic gas adsorbent is below the upper limit, the first acidic gas adsorbent adsorbs a relatively large amount of CO2 on the upstream side, so the acidic gas adsorption efficiency of the entire acidic gas adsorbent does not decrease. Typically, the first acidic gas adsorbent capable of adsorbing CO 2 contains at least tertiary amino groups. The first acidic gas adsorbent may contain only tertiary amino groups as amino groups, or may contain primary and / or secondary amino groups in addition to tertiary amino groups. Examples of the first acidic gas adsorbent having a tertiary amino group include nitrogen-containing compounds having a tertiary amino group, specifically, tertiary amines such as methyldiethylamine and triethanolamine; substituted piperazine compounds such as 1-(2-hydroxyethyl)piperazine; branched polyethyleneimine having primary to tertiary amino groups; and organic / inorganic compounds having a tertiary amino group as a substituent. Such first acidic gas adsorbents can be used alone or in combination. Preferred examples of the first acidic gas adsorbent include methyldiethylamine, branched polyethyleneimine, and organic / inorganic compounds having a tertiary amino group as a substituent. Typically, the second acidic gas adsorbent material capable of adsorbing CO2 comprises primary and / or secondary amino groups. The second acidic gas adsorbent material comprises primary and / or secondary amino groups and does not contain tertiary amino groups. Examples of the second acidic gas adsorbent include nitrogen-containing compounds having primary and / or secondary amino groups. Specific examples of nitrogen-containing compounds having primary and / or secondary amino groups include: primary amines such as monoethanolamine and polyethyleneamine; secondary amines such as diethanolamine, cyclic amines, and N-(3-aminopropyl)diethanolamine; ethyleneamine compounds such as tetraethylenepentamine; aminosilane coupling agents such as aminopropyltrimethoxysilane, 3-aminopropyltriethoxysilane, N-(2-aminoethyl)-3-aminopropyl-trimethoxysilane, and polyethyleneimine-trimethoxysilane; ethyleneimine; linear polyethyleneimine; polyamideamines having primary and / or secondary amino groups; polyethyleneamines having primary and / or secondary amino groups; and organic / inorganic compounds having primary and / or secondary amino groups as substituents. Such second acidic gas adsorbents can be used alone or in combination. Preferred examples of the second acidic gas adsorbent include monoethanolamine, cyclic amines, diethanolamine, tetraethylenepentamine, ethyleneimine, linear polyethyleneimine, and organic / inorganic compounds having primary and / or secondary amino groups as substituents. In one embodiment, the first acidic gas adsorbent is methyl diethylamine and the second acidic gas adsorbent is polyethylene imine. If the first acidic gas adsorbent and the second acidic gas adsorbent are the above-mentioned specific combination, the CO2 adsorption capacity and CO2 adsorption force in the above-mentioned acidic gas adsorption unit can be well balanced, thereby further improving the adsorption performance of the entire acidic gas adsorption device. In one embodiment, an acid gas adsorption device 100 includes: an acid gas adsorption unit 1 including a first adsorption unit 11 and a second adsorption unit 12; and a housing 2. The housing 2 accommodates the acid gas adsorption unit 1. In other words, the housing 2 accommodates the first adsorption unit 11 and the second adsorption unit 12 together. If the housing accommodates the first adsorption unit and the second adsorption unit together, the acid gas adsorption device can be miniaturized compared to a case where the first adsorption unit and the second adsorption unit are accommodated in different housings, so the equipment cost can be suppressed to be relatively low, and the amount of acid gas recovered per unit area can be increased. In the example shown in the figure, the housing 2 has a cylindrical shape extending in the direction in which the fluid passes. The upstream end of the housing 2 in the direction in which the fluid passes is configured as a first opening 21. The downstream end of the housing 2 in the direction in which the fluid passes is configured as a second opening 22. The acid gas adsorption unit 1 is arranged between the first opening 21 and the second opening 22 in the internal space of the housing 2. The first adsorption unit 11 is arranged between the first opening 21 and the second adsorption unit 12. The second adsorption unit 12 is arranged on the opposite side of the first opening 21 relative to the first adsorption unit 11. The first opening 21 and the second opening 22 are respectively capable of allowing fluid to pass through. The fluid containing the acid gas is supplied to the first adsorption unit 11 via the first opening 21. The fluid that has passed through the first adsorption unit 11 and the second adsorption unit 12 in sequence is discharged from the second opening 22. The first adsorption unit 11 includes an upstream end surface 1a of the acid gas adsorption unit 1 in the fluid passing direction. The second adsorption unit 12 includes a downstream end surface 1b of the acid gas adsorption unit 1 in the fluid passing direction. Typically, the fluid passing direction is orthogonal to the upstream end surface 1a and the downstream end surface 1b of the acid gas adsorption unit 1. The size of the acid gas adsorption unit 1 in the direction in which the fluid passes through is not particularly limited as long as the fan driving power due to pressure loss does not increase, and is, for example, 0.5 m or more, preferably 0.6 m or more, and, for example, 2.0 m or less, preferably 1.0 m or less. The size of the acid gas adsorption unit 1 in the direction perpendicular to the direction in which the fluid passes through is not particularly limited, and is, for example, 1.5 m or more, preferably 2.0 m or more, and, for example, 4.0 m or less, preferably 3.0 m or less. When the entire length of the housing 2 in the fluid passing direction is assumed to be 100%, the size ratio of each of the first adsorption part 11 and the second adsorption part 12 is, for example, 10% to 90%, preferably 20% to 80%, and more preferably 30% to 70%. When the size ratios of the first adsorption section and the second adsorption section relative to the housing are within such ranges, it is possible to maintain excellent adsorption force in the entire acid gas adsorption device and ensure a large acid gas adsorption capacity. The distance between the first opening 21 in the passing direction of the fluid and the upstream end surface 1a of the first adsorption part 11 is, for example, 1 cm or more, preferably 5 cm or more, and more preferably 10 cm or more. In addition, the distance between the downstream end surface 1b of the second adsorption part 12 in the passing direction of the fluid and the second opening 22 is, for example, 1 cm or more, preferably 5 cm or more, and more preferably 10 cm or more. By ensuring the distance between the first opening and the upstream end face and / or the distance between the downstream end face and the second opening in this way, the influence of turbulence that may occur at the first opening and the second opening can be reduced, thereby suppressing the increase in energy costs caused by pressure loss in the first adsorption section and the second adsorption section. Regarding the acid gas adsorption unit 1, Figure 2 As shown, the first adsorption part 11 and the second adsorption part 12 can be formed as one body. Figure 1 As shown, in the passing direction of the fluid, it can be divided into a first adsorption portion 11 and a second adsorption portion 12. In one embodiment, the acid gas adsorption unit 1 is divided into a first adsorption unit 11 and a second adsorption unit 12 in the direction of the fluid passing therethrough, and the first adsorption unit 11 and the second adsorption unit 12 are configured as separate bodies (see Figure 1 ). If the first adsorption portion and the second adsorption portion are separated, the first adsorption portion and the second adsorption portion can be manufactured separately and smoothly, compared with the case where the first adsorption portion and the second adsorption portion are manufactured as one body. A gap may be formed between the first adsorption part 11 and the second adsorption part 12 in the passing direction of the fluid. Generally, in the acidic gas adsorption part, the fluid tends to flow near the center and is not easy to flow in the outer part. In this regard, if a gap is formed between the first adsorption part and the second adsorption part, the flow deviation of the fluid in the acidic gas adsorption part can be reduced. In the passing direction of the fluid, the size of the gap is, for example, less than 30%, preferably less than 10%, relative to the total length of the acidic gas adsorption part in the passing direction of the fluid (the sum of the size of the first adsorption part and the size of the second adsorption part in the passing direction of the fluid). If the size of the gap is below the above upper limit, the fluid can be suppressed from being retained between the first adsorption part and the second adsorption part, so that the fluid can flow smoothly from the first adsorption part to the second adsorption part. The respective sizes of the first adsorption section 11 and the second adsorption section 12 in the passing direction of the fluid can adopt any appropriate value according to the acid gas adsorption material used. In one embodiment, the size of the first adsorption section 11 in the passing direction of the fluid is longer than the size of the second adsorption section 12. In the passing direction of the fluid, the size of the first adsorption section 11 is, for example, 50% or more, preferably 60% or more, and for example, 90% or less, preferably 80% or less, relative to the total length of the acid gas adsorption section 1 (the sum of the size of the first adsorption section and the size of the second adsorption section). In the passing direction of the fluid, the size of the second adsorption section 12 is, for example, 10% or more, preferably 30% or more, and for example, 50% or less, preferably 40% or less, relative to the total length of the acid gas adsorption section 1. When the size of the first adsorption unit and / or the second adsorption unit is within the above range, it is possible to stably achieve improvement in the adsorption efficiency of the acid gas. like Figure 3 As shown, in one embodiment, the acid gas adsorption unit 1 further includes a third adsorption unit 13, and the third adsorption unit 13 is disposed between the first adsorption unit 11 and the second adsorption unit 12. Thus, compared with the case where the acid gas adsorption unit is manufactured as one body, the first adsorption unit, the second adsorption unit, and the third adsorption unit can be manufactured separately and smoothly. A gap may be formed in the passing direction of the fluid between the first adsorption part 11 or the second adsorption part 12 and the third adsorption part 13. The size range of the gap between the first adsorption part 11 or the second adsorption part 12 and the third adsorption part 13 is the same as the size range of the gap between the first adsorption part 11 and the second adsorption part 12 described above. The third adsorption part 13 can be Figure 3 The first adsorption unit 11 may contain the same acid gas adsorption material as shown. Figure 4 The acid gas adsorbent material of the first adsorption unit 11 and the acid gas adsorbent material of the second adsorption unit 12 are mixed. In one embodiment, the third adsorption unit 13 includes an acidic gas adsorption material different from the acidic gas adsorption material of the first adsorption unit 11 and the acidic gas adsorption material of the second adsorption unit 12 (see Figure 4 ). The third adsorption unit 13 preferably includes a third acid gas adsorption material. The adsorption force of the third acid gas adsorption material is greater than that of the first acid gas adsorption material and less than that of the second acid gas adsorption material. The adsorption capacity of the third acid gas adsorption material is less than that of the first acid gas adsorption material and greater than that of the second acid gas adsorption material. According to such a configuration, the first acid gas adsorption material, the third acid gas adsorption material, and the second acid gas adsorption material are arranged in such a manner that the adsorption force of the acid gas increases in sequence. Therefore, the CO2 adsorption capacity and the CO2 adsorption force in the acid gas adsorption unit can be ensured in a more balanced manner, thereby further improving the adsorption efficiency of the acid gas in the acid gas adsorption device. The CO2 adsorption capacity of the third acidic gas adsorbent is, for example, 1.2 mol / kg-adsorbent or more, preferably 1.7 mol / kg-adsorbent or more, and more preferably 2.2 mol / kg-adsorbent or more. The equilibrium acid gas concentration (equilibrium CO2 concentration) of the third acidic gas adsorbent is, for example, 150 ppm or less, preferably 125 ppm or less, more preferably 100 ppm or less, and, for example, 75 ppm or more. Specifically, polyethyleneimine can be cited as the third acidic gas adsorbent. like Figure 5 As shown, the first adsorption part 11 can be divided into a plurality of first blocks 11a in a direction orthogonal to the passing direction of the fluid. In other words, the first adsorption part 11 is composed of a plurality of first blocks 11a arranged side by side in a direction orthogonal to the passing direction of the fluid. Thus, a relatively small first block can be manufactured to constitute the first adsorption part. Therefore, compared with the case where the first adsorption part is manufactured together, the first adsorption part can be easily manufactured. The size of the first block 11a in the direction of fluid passage is, for example, 0.10 m or more, preferably 0.15 m or more, and, for example, 0.30 m or less, preferably 0.20 m or less. The size of the first block 11a in the direction orthogonal to the direction of fluid passage is, for example, 0.10 m or more, preferably 0.15 m or more, and, for example, 0.80 m or less, preferably 0.60 m or less. The mutually adjacent first blocks 11 a among the plurality of first blocks 11 a may have a gap formed therebetween, or may be in contact with each other in a direction orthogonal to the direction in which the fluid passes. In the example shown in the figure, the first adsorption portion 11 is divided into four in the direction perpendicular to the passing direction of the fluid (the vertical direction of the paper). The number of divisions of the first adsorption portion in the direction perpendicular to the passing direction of the fluid is not limited thereto. In addition, the first adsorption portion 11 may also be divided into a plurality of parts in the direction perpendicular to the passing direction of the fluid (the depth direction of the paper). The number of divisions of the first adsorption portion in the direction perpendicular to the passing direction of the fluid is, for example, greater than 2 and less than 300. Furthermore, all of the plurality of first blocks 11 a may include the same first acid gas adsorbing material, or some of the plurality of first blocks 11 a may include different first acid gas adsorbing materials. In one embodiment, the second adsorption unit 12 is divided into a plurality of second blocks 12a in a direction perpendicular to the passing direction of the fluid. The second adsorption unit 12 is composed of a plurality of second blocks 12a arranged side by side in a direction perpendicular to the passing direction of the fluid. Thus, a relatively small second block can be manufactured to constitute the second adsorption unit, thereby making it easy to manufacture the second adsorption unit. The size range of the second block 12a is the same as the size range of the first block 11a described above. The second blocks 12 a adjacent to each other among the plurality of second blocks 12 a may have a gap formed therebetween, or may be in contact with each other in a direction orthogonal to the direction in which the fluid passes. In the example shown in the figure, the second adsorption portion 12 is divided into four in the direction perpendicular to the passing direction of the fluid (the vertical direction of the paper). The number of divisions of the second adsorption portion in the direction perpendicular to the passing direction of the fluid is not limited thereto. In addition, the second adsorption portion 12 can also be divided into multiple parts in the direction perpendicular to the passing direction of the fluid (the depth direction of the paper). The number of divisions of the second adsorption portion in the direction perpendicular to the passing direction of the fluid is, for example, greater than 2 and less than 300, and is preferably the same as the number of divisions of the first adsorption portion. Furthermore, all of the plurality of second blocks 12 a may include the same second acid gas adsorbing material, or some of the plurality of second blocks 12 a may include different second acid gas adsorbing materials. In one embodiment, the third adsorption unit 13 is divided into a plurality of third blocks 13a in a direction perpendicular to the passing direction of the fluid. The third adsorption unit 13 is composed of a plurality of third blocks 13a arranged side by side in a direction perpendicular to the passing direction of the fluid. Thus, a relatively small third block can be manufactured to constitute the third adsorption unit, so that the third adsorption unit can be easily manufactured. The size range of the third block 13 a is the same as the size range of the first block 11 a described above. The third blocks 13 a adjacent to each other among the plurality of third blocks 13 a may have a gap formed therebetween, or may be in contact with each other in a direction orthogonal to the direction in which the fluid passes. In the example shown in the figure, the third adsorption portion 13 is divided into four in the direction perpendicular to the passing direction of the fluid (the vertical direction of the paper). The number of divisions of the third adsorption portion in the direction perpendicular to the passing direction of the fluid is not limited thereto. In addition, the third adsorption portion 13 can be divided into a plurality of parts in the direction perpendicular to the passing direction of the fluid (the depth direction of the paper). The number of divisions of the third adsorption portion in the direction perpendicular to the passing direction of the fluid is, for example, greater than 2 and less than 300, and is preferably the same as the number of divisions of the first adsorption portion. Furthermore, all of the plurality of third blocks 13 a may include the same acid gas adsorbing material, or some of the plurality of third blocks 13 a may include different acid gas adsorbing materials. Figure 6 In the third adsorption section 13, the third block 13a located in the center and the third block 13a located in the outer part contain different acid gas adsorbent materials. More specifically, in the third adsorption section 13, the third block 13a located in the center contains the third acid gas adsorbent material, and the third block 13a located in the outer part contains the second acid gas adsorbent material. Figures 3 to 6 In the figure, only the third adsorption section 13 is arranged between the first adsorption section 11 and the second adsorption section 12, but an adsorption section may be further provided between the first adsorption section 11 and the second adsorption section 12. Although not shown in the figure, the acid gas adsorption section 1 may have a third adsorption section to an n-th adsorption section between the first adsorption section 11 and the second adsorption section 12. The n-th adsorption section contains an n-th acid gas adsorption material. The above-mentioned n-th adsorption section may be divided into a plurality of n-th blocks in a direction orthogonal to the passing direction of the fluid in the same manner as described above. n is, for example, greater than 4 and less than 30. In the case where the acid gas adsorption section has the third adsorption section to the n-th adsorption section, it is preferred that the acid gas adsorption material contained in the adsorption section located further downstream in the passing direction of the fluid has a greater adsorption force. Figures 1 to 6 In the acid gas adsorption device 100 shown in FIG. 1 , the acid gas adsorption unit 1 housed in a housing 2 includes a first adsorption unit 11 and a second adsorption unit 12. However, the arrangement of the first adsorption unit and the second adsorption unit is not limited thereto. Figure 7 As shown, two housings 2 may be connected in series in the direction of fluid flow, the upstream housing 2 may contain the first adsorption unit 11, and the downstream housing 2 may contain the second adsorption unit 12. Thus, similar to the above embodiment, the adsorption performance of the acid gas adsorption device can be improved. Hereinafter, the specific structure of the acid gas adsorption unit will be described. B. Acid gas adsorption unit As described above, the acid gas adsorption unit 1 includes at least the first adsorption unit 11 and the second adsorption unit 12. In addition, the acid gas adsorption unit 1 may include the third adsorption unit 13 to the nth adsorption unit. Representatively, the first to nth adsorption units have the same structure except for the type of acid gas adsorption material. Figure 1 The first adsorption portion 11 (integrally formed) and Figure 5 The first block 11a shown has the same structure except for the different size. Figure 5 The structure of the first block 11a shown will be described in detail. In one embodiment, if Figure 8 As shown, the first block 11 a includes a plurality of adsorption material layers 71 . The plurality of adsorbent layers 71 are stacked with a gap in the thickness direction thereof. In the example shown in the figure, five adsorbent layers 71 are arranged in parallel, but the number of adsorbent layers 71 is not limited thereto. The number of adsorbent layers 71 is, for example, 5 or more, preferably 10 or more, and more preferably 20 or more. The gap between adjacent adsorbent layers 71 in the plurality of adsorbent layers 71 is, for example, 0.5 cm or more and 1.5 cm or less. Each of the plurality of adsorbent layers 71 includes a flexible fiber member 73 and a plurality of granular adsorbents 72 . The flexible fiber component 73 allows the passage of gas and restricts the passage of the granular adsorbent material. Typically, the flexible fiber component 73 is formed into a hollow shape (bag shape) capable of accommodating a plurality of granular adsorbent materials 72. The flexible fiber component 73 may be a fabric or a non-woven fabric. Examples of the material of the flexible fiber component 73 include organic fibers and natural fibers, preferably polyethylene terephthalate fibers, polyethylene fibers, and cellulose fibers. The thickness of the flexible fiber component 73 is, for example, not less than 25 μm and not more than 500 μm. A plurality of granular adsorbents 72 are filled inside a flexible fiber member 73 having a hollow shape (bag shape). The granular adsorbent 72 functions as an acid gas adsorbent, and typically functions as a carbon dioxide adsorbent. As the material of the granular adsorbent 72, for example, a material modified with the above-mentioned acid gas adsorbent (the first acid gas adsorbent or the second acid gas adsorbent) can be cited, preferably cellulose modified with the above-mentioned acid gas adsorbent (the first acid gas adsorbent or the second acid gas adsorbent) can be cited, and more preferably nanofibrillated cellulose modified with the above-mentioned acid gas adsorbent (the first acid gas adsorbent or the second acid gas adsorbent) can be cited. The average primary particle size of the granular adsorbent 72 is, for example, not less than 60 μm and not more than 1200 μm. The filling ratio of the granular adsorbent 72 in the adsorbent layer 71 can adopt any appropriate value. The acid gas adsorption device 1 shown in the figure further includes a plurality of spacers 74. The spacers 74 are sandwiched between the adjacent adsorption material layers 71 among the plurality of adsorption material layers 71. Thus, the spacing between the adjacent adsorption material layers can be stably ensured. In one embodiment, the plurality of adsorption material layers 71 and the plurality of spacers 74 are arranged such that: from a direction orthogonal to the thickness direction of the adsorption material layer 71 ( Figure 1 When viewed in the depth direction of the paper, it becomes a roughly Z shape. As such an acid gas adsorption device 1, for example, there can be mentioned a gas separation unit described in International Publication No. 2014 / 170184, the entire contents of which are incorporated herein by reference. In another embodiment, if Fig. 9 and Fig.10 As shown, the first block 11 a typically includes a substrate 3 and an acidic gas adsorption layer 4 . The structure of the substrate 3 is not particularly limited, and examples thereof include a honeycomb structure, a filter structure such as filter cloth, and a particle structure. The acid gas adsorption layer 4 is not particularly limited as long as it is disposed on the surface of the substrate 3 . B-1. Base material (honeycomb base material) In one embodiment, the substrate 3 is a honeycomb substrate 3 a . The honeycomb substrate 3 a includes partition walls 32 defining a plurality of cells 33 . The cells 33 extend from the first end face E1 (inflow end face) to the second end face E2 (outflow end face) of the honeycomb substrate 3a in the longitudinal direction (axial direction) of the honeycomb substrate 3a (see Fig.10). The cell 33 has any appropriate shape in the cross section of the honeycomb substrate 3a in the direction perpendicular to the length direction. Examples of the cross-sectional shape of the cell include: a triangle, a quadrilateral, a pentagon, a polygon larger than a hexagon, a circle, and an ellipse. The cross-sectional shape and size of the cell may be all the same or at least partially different. Among the cross-sectional shapes of such cells, preferably a hexagon or a quadrilateral can be mentioned, and more preferably a square, a rectangle or a hexagon can be mentioned. The cell density in the cross section of the honeycomb substrate in a direction perpendicular to the longitudinal direction (i.e., the number of cells 33 per unit area) can be appropriately set according to the purpose. The cell density can be, for example, 4 cells / cm 2 ~320 compartments / cm 2 When the cell density is within such a range, the strength and effective GSA (geometric surface area) of the honeycomb substrate can be sufficiently ensured. The honeycomb substrate 3a has any appropriate shape (overall shape). As the shape of the honeycomb substrate, for example, there can be cited: a cylindrical shape with a circular bottom surface, an elliptical cylindrical shape with an elliptical bottom surface, a prism shape with a polygonal bottom surface, and a column shape with an irregular bottom surface. The honeycomb substrate 3a shown in the figure has a prism shape. The outer diameter and length of the honeycomb substrate can be appropriately set according to the purpose. Although not shown in the figure, the honeycomb substrate can have a hollow area in the center of the cross section in a direction perpendicular to the longitudinal direction. Typically, the honeycomb substrate 3a includes an outer wall 31 and partition walls 32 located inside the outer wall 31. In the example shown in the figure, the outer wall 31 and the partition walls 32 are formed integrally. The outer wall 31 and the partition walls 32 may be separate bodies. In the example shown in the figure, the outer wall 31 has a square tube shape. The thickness of the outer wall 31 can be set arbitrarily and appropriately. The thickness of the outer wall 31 is, for example, 0.1 mm to 10 mm. The partition wall 32 defines a plurality of compartments 33. More specifically, the partition wall 32 includes a first partition wall 32a and a second partition wall 32b that are orthogonal to each other, and the first partition wall 32a and the second partition wall 32b define a plurality of compartments 33. The cross-sectional shape of the compartment 33 is substantially quadrilateral. It should be noted that the configuration of the partition wall is not limited to the above-mentioned partition wall 32. The partition wall includes: a first partition wall extending in a radial direction, and a second partition wall extending in a circumferential direction, which can define a plurality of compartments. The thickness of the partition wall 32 can be appropriately set according to the purpose of the acid gas adsorption device. Typically, the thickness of the partition wall 32 is thinner than the thickness of the outer wall 31. The thickness of the partition wall 32 is, for example, 0.03 mm to 0.6 mm. The thickness of the partition wall is measured by, for example, cross-sectional observation based on a SEM (scanning electron microscope). If the thickness of the partition wall is within such a range, the mechanical strength of the honeycomb substrate can be sufficient, and the opening area (the total area of ​​the cells in the cross section) can be sufficient. The porosity of the partition walls 32 can be appropriately set according to the purpose. The porosity of the partition walls 32 is, for example, 15% or more, preferably 20% or more, and, for example, 70% or less, preferably 45% or less. The porosity can be measured by, for example, mercury penetration. The bulk density of the partition walls 32 can be appropriately set according to the purpose. For example, the bulk density is 0.10 g / cm 3 Above, preferably 0.20 g / cm 3 Above, for example, 0.60 g / cm 3 Below, preferably 0.50g / cm 3 Hereinafter, the bulk density can be measured by, for example, mercury intrusion porosimetry. As a material constituting the partition wall 32, ceramics can be cited representatively. As ceramics, for example, silicon carbide, silicon-silicon carbide composite materials, cordierite, mullite, alumina, silicon nitride, spinel, silicon carbide-cordierite composite materials, lithium aluminum silicate and aluminum titanate can be cited. The material constituting the partition wall can be used alone or in combination. Among the materials constituting the partition wall, cordierite, alumina, mullite, silicon carbide, silicon-silicon carbide composite materials and silicon nitride can be cited preferably, and silicon carbide and silicon-silicon carbide composite materials can be cited more preferably. Typically, such a honeycomb substrate 3a is produced by the following method. First, a binder and water or an organic solvent are added to the material powder containing the above-mentioned ceramic powder as needed, and the obtained mixture is kneaded to form a blank, and the blank is molded (typically extrusion molded) into a desired shape, and then dried and fired as needed to produce the honeycomb substrate 3a. In the case of firing, for example, the firing is performed at 1200°C to 1500°C. The firing time is, for example, 1 hour or more and 20 hours or less. B-2. Acidic gas adsorption layer (carbon dioxide adsorption layer) In one embodiment, the acid gas adsorption layer 4 is formed on the surface of the partition wall 32. In the honeycomb substrate 3a, a flow path 34 is formed in a portion (representatively, a central portion) of the cross section of the cell 33 where the acid gas adsorption layer 4 is not formed. The acid gas adsorption layer 4 may be formed on the entire inner surface of the partition wall 32 (i.e., surrounding the flow path 34) as shown in the example shown in the figure, or may be formed on a portion of the surface of the partition wall. If the acid gas adsorption layer 4 is formed on the entire inner surface of the partition wall 32, the adsorption efficiency of the acid gas (representatively, CO2) can be improved. The flow path 34 extends from the first end face E1 (inflow end face) to the second end face E2 (outflow end face) in the same manner as the compartment 33. The cross-sectional shape of the flow path 34 may be the same as that of the compartment 33, preferably a hexagon or a quadrilateral, more preferably a square, a rectangle or a hexagon. The cross-sectional shape and size of the flow path 34 may be the same in all or may be at least partially different. Typically, in an adsorption step described later, a fluid containing an acidic gas is supplied to the cell 33 (more specifically, the flow path 34 ). The acid gas adsorption layer 4 contains an acid gas adsorption material corresponding to the acid gas to be adsorbed. The acid gas adsorption layer 4 included in the first adsorption unit 11 (first block 11a) includes the above-mentioned first acid gas adsorption material. The acid gas adsorption layer 4 included in the second adsorption unit 12 (second block 12a) includes the above-mentioned second acid gas adsorption material. In one embodiment, the acid gas adsorbent layer 4 further includes a porous carrier in addition to the above-mentioned acid gas adsorbent (the first acid gas adsorbent or the second acid gas adsorbent). In this case, the acid gas adsorbent is typically supported on the porous carrier so as to face the flow path. If the acid gas adsorbent layer includes a porous carrier, it is possible to suppress the acid gas adsorbent from falling off from the acid gas adsorbent layer during the adsorption process and / or the desorption process. The porous carrier can form mesopores in the acidic gas adsorbent layer. Examples of porous carriers include: organometallic structures (MOFs) such as MOF-74, MOF-200, and MOF-210; activated carbon; nitrogen-doped carbon; mesoporous silica; mesoporous alumina; zeolite; carbon nanotubes; fluorinated resins such as polyvinylidene fluoride (PVDF), preferably: organometallic structures (MOFs), activated carbon, PVDF, zeolite, mesoporous silica, and mesoporous alumina. The porous carrier can be used alone or in combination. The porous carrier preferably uses a material different from the acidic gas adsorbent. The BET specific surface area of ​​the porous carrier is, for example, 50 m 2 / g or more, preferably 500m 2 If the surface area of ​​the porous carrier is greater than the above lower limit, the acid gas adsorbent can be stably supported, thereby improving the adsorption efficiency of the acid gas. The upper limit of the BET specific surface area of ​​the porous carrier is typically 2000 m 2 / g or less. When the acid gas adsorption material layer contains the acid gas adsorption material and the porous carrier, the total content ratio of the acid gas adsorption material and the porous carrier in the acid gas adsorption material layer is, for example, 30 mass% or more, preferably 50 mass% or more, and, for example, 100 mass% or less, preferably 99 mass% or less. The content ratio of the acidic gas adsorbent in the acidic gas adsorbent layer is, for example, 30% by mass or more, preferably 50% by mass or more, and, for example, 99% by mass or less. The content ratio of the porous carrier is, for example, 0.01 parts by mass or more, preferably 0.3 parts by mass or more, and, for example, 0.7 parts by mass or less, preferably 0.5 parts by mass or less, relative to 1 part by mass of the acidic gas adsorbent. If the content ratio of the porous carrier is within the above range, the acidic gas adsorbent can be supported more stably. In addition, the acid gas adsorbent layer may be composed only of the acid gas adsorbent. In this case, the acid gas adsorbent is directly supported on the partition wall 32 and faces the flow path. When the acid gas adsorbent layer is composed only of the acid gas adsorbent, the content of the acid gas adsorbent in the acid gas adsorbent layer is typically 95.0 mass % or more and 100 mass % or less. If the content of the acid gas adsorbent is within the above range, it is possible to stably ensure excellent acid gas adsorption efficiency. Typically, such an acidic gas adsorbent layer is produced by the following method. The above-mentioned acidic gas adsorbent is dissolved in a solvent to prepare a solution of the acidic gas adsorbent. In addition, the above-mentioned porous carrier is added to the solvent as needed. There is no particular restriction on the order of adding the acidic gas adsorbent and the porous carrier. Thereafter, the solution of the acidic gas adsorbent is applied to a substrate (specifically, a partition wall), and then the coating is dried and sintered as needed to form an acidic gas adsorbent layer. C. Acid Gas Recovery Method Next, a method for recovering acid gas using an acid gas adsorption device according to an embodiment of the present invention will be described. Typically, the method for recovering acid gas includes an adsorption step and a desorption step in sequence. In the adsorption process, a fluid containing acid gas is supplied to the acid gas adsorption unit 1 adjusted to a predetermined adsorption temperature. At this time, the fluid containing acid gas first flows into the first adsorption unit 11 (more specifically, the flow path 34 of the first block 11a). As a result, the first acid gas adsorbent contained in the first adsorption unit 11 adsorbs acid gas with a relatively large capacity from the fluid containing acid gas (representatively CO2) at a relatively high concentration. Thereafter, the fluid after the acid gas concentration is reduced flows into the second adsorption unit 12 (more specifically, the flow path 34 of the second block 12a). As a result, the second acid gas adsorbent contained in the second adsorption unit 12 stably adsorbs acid gas from the fluid containing acid gas (representatively CO2) at a relatively low concentration. As a result, acid gas is efficiently adsorbed from the fluid supplied to the acid gas adsorption unit. The temperature of the acid gas adsorption unit in the adsorption process (adsorption temperature) is, for example, 0° C. or more, preferably 10° C. or more, and, for example, 50° C. or less, preferably 40° C. or less. In one embodiment, the adsorption temperature is the same as the outside air temperature. The implementation time of the adsorption process (adsorption time) is, for example, 15 minutes or more, preferably 30 minutes or more, and, for example, 3 hours or less, preferably 2 hours or less. When the adsorption temperature and / or the adsorption time are within the above ranges, the acid gas adsorbent can efficiently adsorb the acid gas. The acid gas adsorption rate in the adsorption process (=100-(acid gas concentration in the fluid that has passed through the acid gas adsorption section / acid gas concentration in the fluid before being supplied to the acid gas adsorption section×100)) is, for example, 60% or more, preferably 75% or more, more preferably 80% or more, and, for example, 90% or less. Next, in the desorption process, the acid gas adsorption unit 1 is typically heated to a desorption temperature exceeding the adsorption temperature. More specifically, in the desorption process, after the acid gas adsorption unit 1 is heated to the desorption temperature, the desorption temperature is maintained for a predetermined desorption time. Thus, the acid gas adsorbed by the acid gas adsorbent (the first acid gas adsorbent and the second acid gas adsorbent) in the adsorption process is desorbed from the acid gas adsorbent. Therefore, the desorbed acid gas can be recovered. In one embodiment, in the desorption process, the desorbed gas is supplied to the acid gas adsorption unit 1, and the desorbed gas passes through the first adsorption unit 11 and the second adsorption unit 12 in sequence, thereby recovering the desorbed acid gas together with the desorbed gas. The gas recovered in the desorption process is sometimes referred to as recovered gas. As the desorbed gas, it is preferred to cite recovered gas that has been previously recovered by the acid gas adsorption device. By using the recovered gas as the desorbed gas, the acid gas concentration in the recovered gas can be increased. It should be noted that in the desorption process, the acid gas can be recovered without using the desorption gas. For example, the desorption acid gas can be sucked and recovered by a pressure reducing pump. In addition, the desorption gas and the pressure reducing pump can be used in combination. The temperature of the acid gas adsorbing unit in the desorption process (desorption temperature) is, for example, 70° C. or more, preferably 80° C. or more, and, for example, 200° C. or less, preferably 110° C. or less. The implementation time of the desorption process (desorption time during which the acid gas adsorbing unit is maintained at the desorption temperature) is, for example, 1 minute or more, preferably 5 minutes or more, and, for example, 1 hour or less, preferably 30 minutes or less. When the desorption temperature and / or the desorption time are within the above ranges, the acid gas can be sufficiently desorbed from each of the first acid gas adsorbing material and the second acid gas adsorbing material. The above operation can efficiently recover the acidic gas. The adsorption step and the desorption step are preferably repeated in sequence. Industrial Applicability The acid gas adsorption device according to the embodiment of the present invention is used for separation and recovery of acid gas, and can be particularly well used in a carbon dioxide recovery, utilization and storage (CCUS) cycle. Explanation of symbols 1Acid gas adsorption unit 11First adsorption unit 12: second adsorption part.

Claims

1. An acid gas adsorption device, comprising: an acid gas adsorption unit, the acid gas adsorption unit including an acid gas adsorption material capable of adsorbing acid gas, and a fluid capable of passing through the acid gas adsorption unit in a predetermined direction; And a housing. The acid gas adsorption unit comprises: A first adsorption part, the first adsorption part comprising a first acid gas adsorption material having a relatively small adsorption force for adsorbing acid gas and a relatively large adsorption capacity for acid gas; as well as a second adsorption part, the second adsorption part being arranged downstream of the first adsorption part in the passing direction of the fluid, and the second adsorption part comprising a second acid gas adsorption material having a relatively large adsorption force for adsorbing acid gas and a relatively small adsorption capacity for acid gas, The one housing accommodates the first adsorption portion and the second adsorption portion together.

2. The acid gas adsorption device according to claim 1, wherein: The acid gas is carbon dioxide.

3. The acid gas adsorption device according to claim 2, wherein: The first acid gas adsorbent material has an equilibrium acid gas concentration exceeding 100 ppm, The second acid gas adsorbent has an equilibrium acid gas concentration of 100 ppm or less.

4. The acid gas adsorption device according to claim 3, wherein: The first acidic gas adsorbent material comprises a tertiary amino group, The second acid gas adsorbent material contains primary and / or secondary amino groups.

5. The acid gas adsorption device according to any one of claims 1 to 4, wherein: The first adsorption portion is divided into a plurality of parts in a direction orthogonal to a passing direction of the fluid.

6. The acid gas adsorption device according to any one of claims 1 to 4, wherein: The second adsorption portion is divided into a plurality of parts in a direction orthogonal to a passing direction of the fluid.

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