Acidic gas adsorbent, structure equipped with acidic gas adsorbent, acidic gas adsorption device, and method for manufacturing acidic gas adsorbent

Abstract

The present invention provides an acidic gas adsorbent which is suitable for performing adsorption and desorption of an acidic gas under relatively mild conditions. An acidic gas adsorbent according to the present invention contains a polymer P which has an amino group. The density of elemental nitrogen in the acidic gas adsorbent is higher than 12.0 mmol / g. When the acidic gas adsorbent is subjected to an adsorption test A1, the amount of carbon dioxide adsorption a1 is 0.35 mmol / g or more. When the acidic gas adsorbent is subjected to a desorption test B1, the amount of carbon dioxide desorption b1 is 0.2 mmol / g or more.

Description

[Technical Field]

[0001] The present invention relates to an acidic gas adsorbent, a structure provided with the acidic gas adsorbent, an acidic gas adsorption device, and a method for producing the acidic gas adsorbent. [Background technology]

[0002] In recent years, carbon capture and storage (CCS) and carbon capture and utilization (CCU) have been considered as a way to reduce the amount of carbon dioxide in the atmosphere. In CCS and CCU, carbon dioxide is sometimes captured by separating it from the atmosphere.

[0003] As a method for separating acidic gases such as carbon dioxide from the atmosphere, an adsorption method has been developed in which the acidic gas is adsorbed onto an adsorbent. The adsorbent used in the adsorption method can adsorb the acidic gas by, for example, contacting the atmosphere.

[0004] Examples of adsorbent materials include amine compounds that have the function of adsorbing acidic gases. For example, Patent Document 1 discloses fibrillated cellulose with amino groups introduced therein as an adsorbent. Patent Document 2 discloses an adsorbent with amino groups introduced inside the pores of a mesoporous material. [Prior art documents] [Patent documents]

[0005] [Patent Document 1] International Publication No. 2017 / 009241 [Patent Document 2] U.S. Patent No. 7,767,004 Summary of the Invention [Problem to be solved by the invention]

[0006] There is a need for an acid gas adsorbent that is suitable for adsorbing and desorbing acid gases under relatively mild conditions. [Means for solving the problem]

[0007] The present invention provides An acidic gas adsorbent comprising a polymer having an amino group, The density of nitrogen element in the acid gas adsorbent is greater than 12.0 mmol / g; When the following adsorption test A1 is performed, the adsorption amount a1 of carbon dioxide is 0.35 mmol / g or more, The present invention provides an acidic gas adsorbent that, when subjected to the following desorption test B1, exhibits a carbon dioxide desorption amount b1 of 0.2 mmol / g or more. Adsorption test A1: A mixed gas consisting of carbon dioxide, nitrogen, and water vapor was continuously fed into the container containing the acid gas adsorbent for 15 hours, where the carbon dioxide concentration in the mixed gas was 400 vol ppm, the mixed gas temperature was 23°C, and the humidity was 50% RH. Desorption test B1: While continuing to feed the mixed gas into the container, the acidic gas adsorbent after the adsorption test A1 is heated at 65°C for 1.5 hours.

[0008] Furthermore, the present invention provides An acidic gas adsorbent comprising a polymer having an amino group, The density of nitrogen element in the acid gas adsorbent is greater than 12.0 mmol / g; The specific surface area of ​​the acid gas adsorbent is 0.5 m 2 / g or more, The acidic gas adsorbent is provided, wherein the polymer has a glass transition temperature of 40°C or lower.

[0009] Furthermore, the present invention provides The acid gas adsorbent, A ventilation path; To provide a structure comprising:

[0010] Furthermore, the present invention provides an adsorption section having a gas inlet and a gas outlet; The present invention provides an acidic gas adsorption device, wherein the adsorption section contains the above-mentioned acidic gas adsorbent.

[0011] Furthermore, the present invention provides The method for producing the acidic gas adsorbent includes the steps of: The production method provides a method for producing an acidic gas adsorbent, which comprises reacting a group of compounds including an amine monomer having a primary amino group to synthesize the polymer. [Effects of the Invention]

[0012] According to the present invention, it is possible to provide an acidic gas adsorbent that is suitable for adsorbing and desorbing acidic gases under relatively mild conditions. [Brief explanation of the drawings]

[0013] [Figure 1] FIG. 2 is a diagram for explaining a method for measuring the amount of carbon dioxide adsorbed by an acidic gas adsorbent. [Figure 2A] FIG. 1 is a perspective view schematically illustrating an example of a structure provided with an acidic gas adsorbent. [Figure 2B] FIG. 10 is a perspective view schematically showing a modified example of a structure provided with an acidic gas adsorbent. [Figure 2C] FIG. 10 is a perspective view schematically showing another modified example of a structure provided with an acidic gas adsorbent. [Figure 3A] FIG. 1 is a perspective view schematically illustrating an example of an acid gas recovery apparatus. [Figure 3B] FIG. 10 is a cross-sectional view showing a schematic configuration of a modified example of an acidic gas recovery device. [Figure 4] 1 shows near-infrared absorption spectra showing the results of near-infrared spectroscopic analysis of the polymers prepared in Examples 1 and 2. DETAILED DESCRIPTION OF THE INVENTION

[0014] The acidic gas adsorbent according to the first aspect of the present invention comprises: An acidic gas adsorbent comprising a polymer having an amino group, The density of nitrogen element in the acid gas adsorbent is greater than 12.0 mmol / g; When the following adsorption test A1 is performed, the adsorption amount a1 of carbon dioxide is 0.35 mmol / g or more, When the following desorption test B1 is performed, the amount of carbon dioxide desorbed b1 is 0.2 mmol / g or more. Adsorption test A1: A mixed gas consisting of carbon dioxide, nitrogen, and water vapor was continuously fed into the container containing the acid gas adsorbent for 15 hours, where the carbon dioxide concentration in the mixed gas was 400 vol ppm, the mixed gas temperature was 23°C, and the humidity was 50% RH. Desorption test B1: While continuing to feed the mixed gas into the container, the acidic gas adsorbent after the adsorption test A1 is heated at 65°C for 1.5 hours.

[0015] In a second aspect of the present invention, for example, in the acidic gas adsorbent according to the first aspect, the adsorption amount a1 is 2.4 mmol / g or more.

[0016] In a third aspect of the present invention, for example, in the acidic gas adsorbent according to the first or second aspect, the desorption amount b1 is 2.0 mmol / g or more.

[0017] In a fourth aspect of the present invention, for example, in the acidic gas adsorbent according to any one of the first to third aspects, when the following adsorption test A2 is carried out, the adsorption amount a2 of carbon dioxide is 0.8 mmol / g or more. Adsorption test A2: The mixed gas was continuously fed into the vessel for 1 hour.

[0018] In a fifth aspect of the present invention, for example, in the acidic gas adsorbent according to any one of the first to fourth aspects, when the following adsorption test A3 is carried out, the adsorption amount a3 of carbon dioxide is 1.9 mmol / g or more. Adsorption test A3: The mixed gas was continuously fed into the vessel for 4 hours.

[0019] The acidic gas adsorbent according to the sixth aspect of the present invention comprises: An acidic gas adsorbent comprising a polymer having an amino group, The density of nitrogen element in the acid gas adsorbent is greater than 12.0 mmol / g; The specific surface area of ​​the acid gas adsorbent is 0.5 m 2 / g or more, The polymer has a glass transition temperature of 40° C. or less.

[0020] In a seventh aspect of the present invention, for example, in the acidic gas adsorbent according to any one of the first to sixth aspects, the glass transition temperature of the polymer is less than -1°C.

[0021] In an eighth aspect of the present invention, for example, in the acidic gas adsorbent according to any one of the first to seventh aspects, the density of nitrogen element in the acidic gas adsorbent is 13.0 mmol / g or more.

[0022] In a ninth aspect of the present invention, for example, in the acidic gas adsorbent according to any one of the first to eighth aspects, the polymer is an amine polymer containing constitutional units derived from epoxy monomers.

[0023] In a tenth aspect of the present invention, for example, in the acidic gas adsorbent according to the ninth aspect, the amine polymer comprises a reaction product of a compound group including an amine monomer and an epoxy monomer.

[0024] In an eleventh aspect of the present invention, for example, in the acidic gas adsorbent according to the tenth aspect, the amine monomer comprises polyethyleneimine.

[0025] In a twelfth aspect of the present invention, for example, the acidic gas adsorbent according to any one of the first to eleventh aspects has a porous structure.

[0026] A structure according to a thirteenth aspect of the present invention comprises: An acidic gas adsorbent according to any one of the first to twelfth aspects; A ventilation path; Equipped with.

[0027] The acid gas adsorption apparatus according to the fourteenth aspect of the present invention comprises: an adsorption section having a gas inlet and a gas outlet; The adsorption section contains an acidic gas adsorbent according to any one of the first to twelfth aspects.

[0028] A method for producing an acidic gas adsorbent according to a fifteenth aspect of the present invention comprises: A method for producing an acidic gas adsorbent according to any one of the first to twelfth aspects, The production method includes reacting a group of compounds including an amine monomer having a primary amino group to synthesize the polymer.

[0029] In a sixteenth aspect of the present invention, for example, in the production method according to the fifteenth aspect, the group of compounds further comprises an epoxy monomer containing an epoxy group, and the ratio E / A of the equivalent E of the epoxy group in the group of compounds to the equivalent A of the active hydrogen of the primary amino group in the group of compounds is less than 0.50.

[0030] The present invention will be described in detail below, but the following description is not intended to limit the present invention to a specific embodiment.

[0031] <Embodiments of acidic gas adsorbents> The acidic gas adsorbent of this embodiment contains an amino group-containing polymer P. The density d of nitrogen elements in the acidic gas adsorbent is greater than 12.0 mmol / g.

[0032] The density d of the nitrogen element in the acidic gas adsorbent is preferably 12.2 mmol / g or more, and may be 12.5 mmol / g or more, 13.0 mmol / g or more, 13.5 mmol / g or more, 14.0 mmol / g or more, 14.5 mmol / g or more, 15.0 mmol / g or more, 15.5 mmol / g or more, 16.0 mmol / g or more, 16.5 mmol / g or more, 17.0 mmol / g or more, or even 17.5 mmol / g or more. The larger the density d of the nitrogen element, the greater the amount of acidic gas adsorbed by the acidic gas adsorbent and the rate at which the acidic gas is adsorbed. The upper limit of the density d of the nitrogen element is not particularly limited and may be, for example, 30 mmol / g or 20 mmol / g. In this specification, the density d of the nitrogen element in the acidic gas adsorbent refers to the amount of nitrogen element contained in 1 g of the acidic gas adsorbent. When all of the nitrogen elements contained in the acidic gas adsorbent are derived from amino groups, the density d of the nitrogen elements can be regarded as the density of the amino groups in the acidic gas adsorbent.

[0033] The density d of the nitrogen element can be measured by the following method. First, the weight ratio w (wt%) of the nitrogen element contained in the acidic gas adsorbent is measured using a commercially available CHN elemental analyzer. Based on the obtained results, the density d of the nitrogen element can be calculated using the following formula. Density d (mmol / g) = (weight ratio w (wt%) × 1000) / (atomic weight of nitrogen × 100)

[0034] When the acidic gas adsorbent of this embodiment is subjected to the following adsorption test A1, the adsorption amount a1 of carbon dioxide is 0.35 mmol / g or more. Furthermore, when the following desorption test B1 is performed, the desorption amount b1 of carbon dioxide is 0.2 mmol / g or more. Adsorption test A1: A mixed gas G consisting of carbon dioxide, nitrogen, and water vapor was fed into a container containing an acidic gas adsorbent for 15 hours. The carbon dioxide concentration in the mixed gas G was 400 vol ppm, the temperature of the mixed gas G was 23°C, and the humidity was 50% RH. Desorption test B1: While continuing to feed the mixed gas G into the above-mentioned container, the acidic gas adsorbent after the adsorption test A1 is heated at 65°C for 1.5 hours.

[0035] (Adsorption and desorption tests) The adsorption test A1 and the desorption test B1 will be described in detail below. The adsorption test A1 and the desorption test B1 can be performed using a measurement device 20 shown in FIG. 1. The measurement device 20 includes a first tank 30 and a second tank 31. As an example, the first tank 30 stores dry nitrogen, and the second tank 31 stores a mixed gas of dry nitrogen and dry carbon dioxide. The concentration of carbon dioxide in the mixed gas in the second tank 31 is, for example, 5 vol%.

[0036] The measuring device 20 further includes a first container 40 containing water 70, and a first path 60 for sending nitrogen from the first tank 30 to the first container 40. The first path 60 has one end connected to the gas outlet of the first tank 30 and the other end located in the water 70 of the first container 40. The nitrogen sent from the first tank 30 to the first container 40 is humidified by coming into contact with the water 70. A mass flow controller 35 is arranged in the first path 60 to adjust the flow rate of nitrogen sent from the first tank 30 to the first container 40.

[0037] The measuring device 20 further includes a second container 41, a second path 62, and a bypass path 61. The second path 62 connects the first container 40 and the second container 41. The humidified nitrogen sent to the first container 40 is sent to the second container 41 via the second path 62. The bypass path 61 branches off from the first path 60 at a position between the first tank 30 and the mass flow controller 35 and connects to the second path 62. A portion of the nitrogen sent from the first tank 30 flows into the bypass path 61 and is sent to the second container 41 via the second path 62. A mass flow controller 36 is disposed in the bypass path 61 to adjust the flow rate of nitrogen sent from the first tank 30 to the bypass path 61.

[0038] The measuring device 20 further includes a third path 63 for sending the mixed gas from the second tank 31 to the second path 62. The third path 63 has one end connected to the gas outlet of the second tank 31 and the other end connected to the second path 62. A mass flow controller 37 is disposed in the third path 63 for adjusting the flow rate of the mixed gas sent from the second tank 31 to the second path 62. The mixed gas sent to the second path 62 is sent to the second container 41 via the second path 62.

[0039] The measurement device 20 further includes a third container 42 and a fourth path 64. The third container 42 contains water 71 and an adsorption unit 21 disposed in the water 71. In the third container 42, the temperature of the water 71 is maintained at 23°C. The adsorption unit 21 has a gas inlet 22 and a gas outlet 23. The adsorption unit 21 functions as a container that contains an acidic gas adsorbent therein. The adsorption unit 21 is configured to prevent water 71 from penetrating into the interior. The adsorption unit 21 is typically a tube made of a hydrophobic resin, for example, a fluororesin such as tetrafluoroethylene-perfluoroalkoxyethylene copolymer (PFA). As an example, the tube serving as the adsorption unit 21 has an inner diameter of 4 mm and an outer diameter of 6 mm. The adsorption unit 21 is configured to be detachable from the measurement device 20.

[0040] The measuring device 20 can also be used as an acidic gas adsorption device equipped with an adsorption unit 21. In another aspect, the present invention provides an acidic gas adsorption device 20 equipped with an adsorption unit 21 having a gas inlet 22 and a gas outlet 23, and the adsorption unit 21 houses an acidic gas adsorbent.

[0041] The fourth path 64 connects the second container 41 and the third container 42. More specifically, the fourth path 64 is connected to the gas inlet 22 of the adsorption unit 21 in the third container 42. A first concentration meter 50 is disposed in the fourth path 64 to measure the concentration of carbon dioxide in the gas supplied to the adsorption unit 21. A CO2 / H2O gas analyzer LI-850-3 manufactured by LI-COR Corporation can be used as the first concentration meter 50.

[0042] The measurement device 20 further includes a fifth path 65 connected to the gas outlet 23 of the adsorption unit 21 for discharging gas from the adsorption unit 21 to the outside of the measurement device 20. A back pressure valve 55 and a second concentration meter 51 are disposed in the fifth path 65. The back pressure valve 55 allows the pressure inside the adsorption unit 21 to be adjusted to a constant value. The second concentration meter 51 can measure the concentration of carbon dioxide in the gas discharged from the adsorption unit 21. The second concentration meter 51 can be a CO2 / H2O gas analyzer LI-850-3 manufactured by LI-COR.

[0043] Each path of the measuring device 20 is preferably made of metal or resin piping.

[0044] [Preprocessing] First, an acidic gas adsorbent is prepared and dried. The acidic gas adsorbent is used before undergoing the heat resistance test and moist heat resistance test described below. The drying process is preferably performed by treating the acidic gas adsorbent for at least two hours under conditions of 60°C in a vacuum atmosphere. Next, the dried acidic gas adsorbent is packed into the adsorption unit 21 in a dry room with a dew point of approximately -60°C. The weight of the acidic gas adsorbent packed into the adsorption unit 21 is, for example, 50 mg. Next, a fourth path 64 and a fifth path 65 are connected to both ends of the adsorption unit 21, and the adsorption unit 21 is immersed in water 71 in the third container 42.

[0045] Next, nitrogen from the first tank 30 and the mixed gas from the second tank 31 are supplied to the second container 41 via the first path 60, the second path 62, the bypass path 61, and the third path 63 of the measuring device 20. These gases are mixed in the second container 41 to obtain a mixed gas G composed of carbon dioxide, nitrogen, and water vapor. In the second container 41, the carbon dioxide concentration in the mixed gas G is adjusted to 400 vol ppm. The mixed gas G has a temperature of 23°C and a humidity of 50% RH. The mixed gas G is supplied to the adsorption unit 21 via the fourth path 64 at a flow rate sufficient for the weight of the acidic gas adsorbent, for example, a flow rate of 300 mL / min for 50 mg of acidic gas adsorbent. In the adsorption unit 21, the pressure of the mixed gas G is adjusted to, for example, 107 kPa by the back pressure valve 55.

[0046] Next, while the mixed gas G is being supplied to the adsorption unit 21, the adsorption unit 21 is removed from the third container 42 and immersed in a water bath (not shown) at 80°C for two hours or more. The adsorption unit 21 is immersed in the water bath until the carbon dioxide concentration measured by the first concentration meter 50 and the carbon dioxide concentration measured by the second concentration meter 51 become substantially the same value. This completes the pretreatment of the acidic gas adsorbent in the adsorption unit 21.

[0047] [Adsorption test] Next, while the mixed gas G is being supplied to the adsorption unit 21, the adsorption unit 21 is removed from the hot water bath and immersed in the water 71 in the third container 42. This starts a carbon dioxide adsorption test (adsorption test A1) for the acidic gas adsorbent in the adsorption unit 21. The adsorption test is carried out for 15 hours after it has started. Specifically, the mixed gas G continues to be supplied to the adsorption unit 21 for 15 hours. When the adsorption test has been carried out for 15 hours, it can generally be considered that the adsorption of carbon dioxide by the acidic gas adsorbent has reached equilibrium.

[0048] In the adsorption test A1, the amount of carbon dioxide adsorbed by the acid gas adsorbent over 15 hours from the start is measured as M1. The amount of carbon dioxide adsorbed by the acid gas adsorbent can be calculated from the results of measuring the difference over time between the carbon dioxide concentration measured by the first concentration meter 50 and the carbon dioxide concentration measured by the second concentration meter 51. The amount of carbon dioxide adsorbed by 1 g of the acid gas adsorbent over 15 hours is calculated based on the amount of carbon dioxide M1, and the calculated value is identified as the adsorption amount a1.

[0049] [Desorption test] Next, while the mixed gas G continues to be sent to the adsorption unit 21, the adsorption unit 21 is removed from the third container 42 and immersed in a water bath (not shown) at 65°C. This starts a carbon dioxide desorption test (desorption test B1) for the acidic gas adsorbent in the adsorption unit 21. The desorption test is continued for 1.5 hours after the start.

[0050] In desorption test B1, the amount of carbon dioxide desorbed from the acid gas adsorbent within 1.5 hours from the start is measured, M2. The amount of carbon dioxide desorbed from the acid gas adsorbent can be calculated from the results of measuring the difference over time between the carbon dioxide concentration measured by first concentration meter 50 and the carbon dioxide concentration measured by second concentration meter 51. Based on the amount of substance M2, the amount of carbon dioxide desorbed from 1 g of acid gas adsorbent in 1.5 hours is calculated, and the calculated value is identified as the desorption amount b1.

[0051] [Amount of adsorption and desorption] In the acidic gas adsorbent of this embodiment, the carbon dioxide adsorption amount a1 when adsorption test A1 is performed is preferably 0.4 mmol / g or more, 0.5 mmol / g or more, 0.8 mmol / g or more, 1.0 mmol / g or more, 1.3 mmol / g or more, 1.5 mmol / g or more, 1.8 mmol / g or more, 2.0 mmol / g or more, 2.3 mmol / g or more, 2.4 mmol / g or more, 2.5 mmol / g or more, 2.8 mmol / g or more, 3.0 mmol / g or more, 3.3 mmol / g or more, or even 3.5 mmol / g or more. The upper limit of the carbon dioxide adsorption amount a1 is not particularly limited, and is, for example, 10 mmol / g.

[0052] In the acidic gas adsorbent of this embodiment, the carbon dioxide desorption amount b1 when desorption test B1 is performed is preferably 0.25 mmol / g or more, 0.3 mmol / g or more, 0.5 mmol / g or more, 0.8 mmol / g or more, 1.0 mmol / g or more, 1.3 mmol / g or more, 1.5 mmol / g or more, 1.8 mmol / g or more, 2.0 mmol / g or more, 2.3 mmol / g or more, 2.5 mmol / g or more, 2.8 mmol / g or more, 3.0 mmol / g or more, 3.3 mmol / g or more, or even 3.5 mmol / g or more. The upper limit of the carbon dioxide desorption amount b1 is not particularly limited, and is, for example, 10 mmol / g.

[0053] The ratio of the desorption amount b1 (mmol / g) to the adsorption amount a1 (mmol / g) (65°C desorption rate) is, for example, 40% or more, and may be 45% or more, 50% or more, 60% or more, 70% or more, 80% or more, 90% or more, 95% or more, 96% or more, or even 97% or more, or may be 100%.

[0054] From another aspect, the present invention provides: An acidic gas adsorbent comprising a polymer P having an amino group, The density of the nitrogen element in the acid gas adsorbent is greater than 12.0 mmol / g; When the above adsorption test A1 is performed, the adsorption amount a1 of carbon dioxide is 0.35 mmol / g or more, The present invention provides an acidic gas adsorbent having a ratio (65°C desorption rate) of the carbon dioxide desorption amount b1 (mmol / g) when the above-mentioned desorption test B1 is carried out to the adsorption amount a1 (mmol / g) of 40% or more. In this acidic gas adsorbent, the 65°C desorption rate may satisfy the range exemplified above, and may particularly be 50% or more.

[0055] When the acidic gas adsorbent of this embodiment is subjected to the following desorption test B2, the amount b2 of carbon dioxide desorbed is preferably 0.2 mmol / g or more. Desorption test B2: While continuing to send the mixed gas G to the container (the adsorption section 21) containing the acidic gas adsorbent, the acidic gas adsorbent after the adsorption test A1 is heated at 50°C for 1.5 hours.

[0056] Desorption test B2 can be performed in the same manner as desorption test B1, except that the adsorption unit 21 is immersed in a water bath at 50°C. The amount b2 of carbon dioxide desorption when desorption test B2 is performed is preferably 0.25 mmol / g or more, and may be 0.3 mmol / g or more, 0.5 mmol / g or more, 0.8 mmol / g or more, 1.0 mmol / g or more, 1.3 mmol / g or more, 1.5 mmol / g or more, 1.8 mmol / g or more, 2.0 mmol / g or more, or even 2.3 mmol / g or more. The upper limit of the amount b2 of carbon dioxide desorption is not particularly limited, and may be, for example, 10 mmol / g.

[0057] The ratio of the desorption amount b2 (mmol / g) to the adsorption amount a1 (mmol / g) (50°C desorption rate) is, for example, 40% or more, and may be 45% or more, 50% or more, 60% or more, 70% or more, 80% or more, or even 90% or more. The upper limit of the 50°C desorption rate is not particularly limited and is, for example, 99%.

[0058] When the following adsorption test A2 is performed on the acidic gas adsorbent of this embodiment, the carbon dioxide adsorption amount a2 is preferably 0.05 mmol / g or more. The adsorption amount a2 can be used as an index of the rate at which acidic gases are adsorbed. In other words, the larger the adsorption amount a2, the faster the acidic gas adsorbent adsorbs acidic gases. Adsorption test A2: The mixed gas G is continuously fed into the container (the adsorption section 21) containing the acidic gas adsorbent for one hour.

[0059] Adsorption Test A2 can be performed in the same manner as Adsorption Test A1, except that the test time is changed from 15 hours to 1 hour. The carbon dioxide adsorption amount a2 obtained by Adsorption Test A2 is preferably 0.1 mmol / g or more, and may be 0.2 mmol / g or more, 0.3 mmol / g or more, 0.4 mmol / g or more, 0.5 mmol / g or more, 0.6 mmol / g or more, 0.7 mmol / g or more, 0.8 mmol / g or more, 0.9 mmol / g or more, 1.0 mmol / g or more, 1.1 mmol / g or more, or even 1.2 mmol / g or more. The upper limit of the carbon dioxide adsorption amount a2 is not particularly limited, and may be, for example, 5 mmol / g.

[0060] When the acidic gas adsorbent of this embodiment is subjected to the following adsorption test A3, the carbon dioxide adsorption amount a3 is preferably 0.1 mmol / g or more. The adsorption amount a3 can also be used as an index of the rate at which the acidic gas is adsorbed. In other words, the larger the adsorption amount a3, the faster the acidic gas adsorbent adsorbs the acidic gas. Adsorption test A3: The mixed gas G is continuously fed into the container (the adsorption section 21) containing the acidic gas adsorbent for 4 hours.

[0061] Adsorption Test A3 can be performed in the same manner as Adsorption Test A1, except that the test time is changed from 15 hours to 4 hours. The carbon dioxide adsorption amount a3 obtained by Adsorption Test A3 is preferably 0.3 mmol / g or more, and may be 0.5 mmol / g or more, 0.8 mmol / g or more, 1.0 mmol / g or more, 1.3 mmol / g or more, 1.5 mmol / g or more, 1.8 mmol / g or more, 1.9 mmol / g or more, 2.0 mmol / g or more, or even 2.3 mmol / g or more. The upper limit of the carbon dioxide adsorption amount a3 is not particularly limited, and may be, for example, 5 mmol / g.

[0062] (Heat resistance test) The acidic gas adsorbent of this embodiment preferably has high heat resistance. The heat resistance of the acidic gas adsorbent can be evaluated by conducting a heat resistance test on the acidic gas adsorbent. The heat resistance test can be performed by subjecting the acidic gas adsorbent to a heat treatment for 100 hours in an environment of 85°C and 10% RH. As an example, when the acidic gas adsorbent is subjected to a heat treatment for 100 hours in an environment of 85°C and 10% RH, the retention rate R1 of the amount of adsorbable carbon dioxide (mmol / g) is, for example, 30% or more, 40% or more, 50% or more, 60% or more, 70% or more, 80% or more, 85% or more, 90% or more, 92% or more, 94% or more, 95% or more, or even 96% or more. The higher the retention rate R1, the higher the heat resistance of the acidic gas adsorbent. An acidic gas adsorbent with high heat resistance can be said to have high durability in long-term use. The upper limit of the retention rate R1 is not particularly limited and may be, for example, 99%.

[0063] Specifically, the retention rate R1 can be determined by the following method. First, the acidic gas adsorbent is placed in a glass container (e.g., a Labolan screw cap bottle manufactured by AS ONE Corporation) in a dry room with a dew point of approximately -60°C. Next, the glass container is placed in a thermo-hygrostat (e.g., a PSL-2J manufactured by ESPEC Corporation) and heat-treated in air at 85°C and 10% RH for 100 hours. Next, the heat-treated acidic gas adsorbent is placed in a vacuum dryer (e.g., a VOS-310C manufactured by EYELA Corporation) in the dry room and treated in a vacuum atmosphere at 60°C for two hours or more. The carbon dioxide adsorption amount a4 of the treated acidic gas adsorbent is measured when the above-mentioned adsorption test A1 is performed. The retention rate R1 can be calculated using the following formula based on the obtained adsorption amount a4 and the carbon dioxide adsorption amount a1 of the acidic gas adsorbent before the heat resistance test when the adsorption test A1 is performed. Maintenance rate R1 (%) = adsorption amount a4 (mmol / g) ÷ adsorption amount a1 (mmol / g) × 100

[0064] The carbon dioxide adsorption amount a4 may be, for example, 0.35 mmol / g or more, 0.4 mmol / g or more, 0.5 mmol / g or more, 0.8 mmol / g or more, 1.0 mmol / g or more, 1.3 mmol / g or more, 1.5 mmol / g or more, 1.8 mmol / g or more, 2.0 mmol / g or more, 2.3 mmol / g or more, 2.4 mmol / g or more, 2.5 mmol / g or more, 2.8 mmol / g or more, 3.0 mmol / g or more, 3.3 mmol / g or more, or even 3.5 mmol / g or more. The upper limit of the carbon dioxide adsorption amount a4 is not particularly limited and may be, for example, 10 mmol / g.

[0065] (Heat and humidity resistance test) The acidic gas adsorbent of this embodiment preferably has high moist heat resistance. The moist heat resistance of the acidic gas adsorbent can be evaluated by conducting a moist heat resistance test on the acidic gas adsorbent. The moist heat resistance test can be performed by subjecting the acidic gas adsorbent to a heat treatment for 100 hours in an environment at 85°C and 85% RH. As an example, when the acidic gas adsorbent is subjected to a heat treatment for 100 hours in an environment at 85°C and 85% RH, the retention rate R2 of the amount of adsorbable carbon dioxide (mmol / g) is, for example, 30% or more, and may be 40% or more, 50% or more, 60% or more, 70% or more, 80% or more, 85% or more, 90% or more, 95% or more, or even 96% or more. The higher the retention rate R2, the higher the moist heat resistance of the acidic gas adsorbent. An acidic gas adsorbent with high moist heat resistance can be said to have high durability in long-term use. The upper limit of the retention rate R2 is not particularly limited and may be, for example, 99%.

[0066] Specifically, the retention rate R2 can be determined by the following method. First, the acidic gas adsorbent is placed in a glass container (e.g., a Labolan screw cap bottle manufactured by AS ONE Corporation) in a dry room with a dew point of approximately -60°C. Next, the glass container is placed in a thermo-hygrostat (e.g., a PSL-2J manufactured by ESPEC Corporation) and heat-treated in air at 85°C and 85% RH for 100 hours. Next, the heat-treated acidic gas adsorbent is placed in a vacuum dryer (e.g., a VOS-310C manufactured by EYELA Corporation) in the dry room and treated in a vacuum atmosphere at 60°C for two hours or more. The carbon dioxide adsorption amount a5 of the treated acidic gas adsorbent is measured when the above-mentioned adsorption test A1 is performed. The retention rate R2 can be calculated using the following formula based on the obtained adsorption amount a5 and the carbon dioxide adsorption amount a1 of the acidic gas adsorbent before the moist heat resistance test when the adsorption test A1 is performed. Maintenance rate R2 (%) = adsorption amount a5 (mmol / g) ÷ adsorption amount a1 (mmol / g) × 100

[0067] The carbon dioxide adsorption amount a5 is, for example, 0.35 mmol / g or more, and may be 0.4 mmol / g or more, 0.5 mmol / g or more, 0.8 mmol / g or more, 1.0 mmol / g or more, 1.3 mmol / g or more, 1.5 mmol / g or more, 1.8 mmol / g or more, 2.0 mmol / g or more, 2.3 mmol / g or more, 2.4 mmol / g or more, 2.5 mmol / g or more, 2.8 mmol / g or more, 3.0 mmol / g or more, 3.3 mmol / g or more, or even 3.5 mmol / g or more. The upper limit of the carbon dioxide adsorption amount a5 is not particularly limited and may be, for example, 10 mmol / g.

[0068] (polymer) In the acidic gas adsorbent, the polymer P has the function of adsorbing acidic gases due to amino groups. The polymer P preferably contains at least one amino group selected from the group consisting of primary amino groups, secondary amino groups, and tertiary amino groups. From the viewpoint of acidic gas adsorption properties, the polymer P preferably contains at least one amino group selected from the group consisting of primary amino groups and secondary amino groups, and preferably contains both primary amino groups and secondary amino groups. The larger the amount of primary amino groups and secondary amino groups (particularly primary amino groups) in the polymer P, the higher the density d of nitrogen elements in the acidic gas adsorbent and the above-mentioned adsorption amounts a1 to a3 (particularly adsorption amount a1) tend to be. When the amount of primary amino groups and secondary amino groups (particularly secondary amino groups) in the polymer P is large, the acidic gas adsorbent tends to be able to easily desorb the adsorbed acidic gases. The polymer P having primary amino groups or secondary amino groups allows the acidic gas adsorbent to be regenerated under relatively mild conditions. The polymer P may contain a tertiary amino group, but may not contain a tertiary amino group.

[0069] In this embodiment, in the near-infrared absorption spectrum (spectral data) obtained by performing near-infrared spectroscopy (NIR) on the polymer P, -1 Peak intensity I of the absorption peak present in the vicinity B The wave number is 4930 cm -1Peak intensity I of the absorption peak present in the vicinity A Ratio of I A / I B It is preferable that the value of the wavenumber of the polymer P is 0.80 or more. Usually, when the polymer P contains a primary amino group and a secondary amino group, the value of the wavenumber of the polymer P is 6500 cm -1 Absorption peaks due to primary and secondary amino groups are observed around the wavenumber of 4930 cm -1 An absorption peak due to the primary amino group is observed around the A / I B can be used as an index for the ratio of the amount of primary amino groups to the amount of secondary amino groups in polymer P. NIR can be performed using a transparent test piece obtained by press-molding polymer P. This test piece tends to be less susceptible to light scattering, which can affect the NIR results.

[0070] Ratio I A / I B is more preferably 0.90 or more, and may be 0.95 or more, 1.00 or more, 1.05 or more, 1.10 or more, 1.15 or more, or even 1.20 or more. A / I B The higher the ratio I, the greater the amount of adsorption a1 to a3 (particularly the amount of adsorption a1). A / I B The upper limit of is not particularly limited, and is, for example, 1.50 or less.

[0071] The weight ratio of nitrogen elements in polymer P is, for example, 5 wt% or more, preferably 10 wt% or more. The higher this weight ratio, the more the acidic gas adsorption ability of the acidic gas adsorbent tends to improve. The upper limit of the weight ratio of nitrogen elements in polymer P is not particularly limited, and is, for example, 30 wt%. Note that when all of the nitrogen elements contained in polymer P are derived from amino groups, the weight ratio of nitrogen elements described above can be regarded as the weight ratio of amino groups in polymer P.

[0072] The density of the nitrogen element in the polymer P is, for example, greater than 12.0 mmol / g, preferably 12.2 mmol / g or greater, and may be 12.5 mmol / g or greater, 13.0 mmol / g or greater, 13.5 mmol / g or greater, 14.0 mmol / g or greater, 14.5 mmol / g or greater, 15.0 mmol / g or greater, 15.5 mmol / g or greater, 16.0 mmol / g or greater, 16.5 mmol / g or greater, 17.0 mmol / g or greater, or even 17.5 mmol / g or greater. The upper limit of the nitrogen element density is not particularly limited and may be, for example, 30 mmol / g or 20 mmol / g. In this specification, the density of the nitrogen element in the polymer P refers to the amount of nitrogen element contained in 1 g of the polymer P, and can be measured by the same method as the density d of the nitrogen element in the acidic gas adsorbent described above. When all of the nitrogen elements contained in the polymer P are derived from amino groups, the density of the nitrogen elements can be considered to be the density of the amino groups in the polymer P.

[0073] The polymer P may contain functional groups other than amino groups. Examples of such functional groups include hydroxyl groups, ether groups, ester groups, and amide groups. The polymer P preferably contains an ether group as the functional group.

[0074] The polymer P is preferably an amine polymer, particularly an amine polymer comprising a building block U1 derived from an epoxy monomer, which may comprise a reactant P1 of a compound group comprising an amine monomer, particularly a compound group comprising an amine monomer and an epoxy monomer.

[0075] As described above, the group of compounds for forming the reactant P1 includes an amine monomer and an epoxy monomer. The reactant P1 may be a polymer of a group of monomers including an amine monomer and an epoxy monomer (particularly a polymer of an amine monomer and an epoxy monomer). The reactant P1 may also be a crosslinked product of an amine monomer with an epoxy monomer. A crosslinked product of an amine monomer with an epoxy monomer tends to have a high nitrogen element density as well as high heat resistance and moist heat resistance. When preparing the reactant P1 having a crosslinked structure, it is preferable that at least one selected from the group consisting of the amine monomer and the epoxy monomer is a multifunctional monomer having two or more functionalities, particularly three or more functionalities.

[0076] The amine monomer is a monomer containing at least one amino group, preferably at least one primary amino group. The number of primary amino groups contained in the amine monomer is preferably two or more, may be three or more, or may be four or more. The upper limit of the number of primary amino groups is not particularly limited and may be, for example, 100 or 10. The amine monomer may contain secondary amino groups or tertiary amino groups in addition to primary amino groups, but may not contain tertiary amino groups. In the amine monomer, the ratio of the number of primary amino groups to the total number of amino groups is not particularly limited and may be, for example, 10% or more, preferably 20% or more, more preferably 30% or more, or even 40% or more. The higher this ratio, the more crosslinking points in the amine monomer and the denser the crosslinked structure in the reactant P1, which tends to improve heat resistance and moist heat resistance. The upper limit of this ratio is not particularly limited and may be, for example, 80% or 60%.

[0077] The molecular weight (weight average molecular weight in some cases) of the amine monomer is, for example, 50 or more, and may be 100 or more, 150 or more, 200 or more, 300 or more, 500 or more, 1000 or more, or even 1500 or more. The larger the molecular weight of the amine monomer, the easier it is to greatly adjust the density of the nitrogen element in the reactant P1. Furthermore, amine monomers with larger molecular weights tend to be safer to handle. The upper limit of the molecular weight of the amine monomer is, for example, 5000, or may be 2000 or less. The molecular weight of the amine monomer may, in some cases, be less than 1000, 500 or less, or even 300 or less. The amine equivalent of the amine monomer is, for example, 10 g / eq. or more, preferably 20 g / eq. or more, and more preferably 30 g / eq. or more. The larger the amine equivalent of the amine monomer, the easier it is to greatly adjust the density of the nitrogen element in the reactant P1. The upper limit of the amine equivalent of the amine monomer is not particularly limited and may be, for example, 200 g / eq. or less, 150 g / eq. or less, 100 g / eq. or less, or even 50 g / eq. or less. In this specification, the amine equivalent means the mass of the amine monomer relative to 1 equivalent of the active hydrogen of the primary amino group contained in the amine monomer. When the amine monomer contains repeating units (structural units), the number of structural units contained in the amine monomer (degree of polymerization) is not particularly limited and is, for example, 5 to 100.

[0078] Examples of the amine monomers include ethylamine, ethylenediamine, 1,4-butylenediamine, 1,5-pentanediamine, 1,6-hexanediamine, 1,7-heptanediamine, 1,8-octanediamine, diethylenetriamine, triethylenetetramine, tetraethylenepentamine, pentaethylenehexamine, hexaethyleneheptamine, iminobispropylamine, bis(hexamethylene)triamine, 1,3,6-trisaminomethylhexane, tris(2-aminoethyl)amine, N,N'-bis(3-aminopropyl)ethylenediamine, polymethylenediamine, trimethylhexamethylenediamine, polyether Examples of suitable amine monomers include aliphatic amines such as butyldiamine; alicyclic amines such as isophoronediamine, menthanediamine, piperazine, N-aminoethylpiperazine, 3,9-bis(3-aminopropyl)2,4,8,10-tetraoxaspiro(5,5)undecane adduct, bis(4-amino-3-methylcyclohexyl)methane, bis(4-aminocyclohexyl)methane, and modified versions thereof; aliphatic polyamines such as polyethyleneimine and polyalkylenepolyamines; (meth)acrylic polymers having amino groups such as aminoethylated acrylic polymers; and aliphatic polyamidoamines formed by the reaction of polyamines with dimer acids. The amine monomer preferably includes aliphatic amines (particularly triethylenetetramine (TETA)) and aliphatic polyamines (particularly polyethyleneimine (PEI)). The amine monomers can be used alone or in combination of two or more.

[0079] In addition, aliphatic polyamines, particularly PEI, tend to be highly safe to handle. For example, amine monomers such as aliphatic polyamines are preferably not classified as hazardous materials under the Fire Service Act and are preferably not subject to the Poisonous and Deleterious Substances Control Act. The amine monomers preferably have negative results in mutagenicity tests (Ames tests). The amine monomers preferably have mild or moderate irritation results in skin irritation tests (primary skin irritation tests using rabbits).

[0080] The epoxy monomer is a monomer containing at least one epoxy group. The number of epoxy groups contained in the epoxy monomer is preferably 2 or more, but may be 3 or more, or 4 or more. The greater the number of epoxy groups, the more crosslinking points in the epoxy monomer and the denser the crosslinked structure in the reaction product P1, which tends to improve heat resistance and moist heat resistance. The upper limit of the number of epoxy groups contained in the epoxy monomer is not particularly limited and is, for example, 10.

[0081] The molecular weight of the epoxy monomer is not particularly limited and is, for example, less than 1,000, preferably 500 or less. The epoxy equivalent of the epoxy monomer is not particularly limited and is, for example, 150 g / eq. or less, preferably 100 g / eq. or less. The smaller the epoxy equivalent of the epoxy monomer, the higher the density of nitrogen elements in the reactant P1 tends to be. The lower limit of the epoxy equivalent of the epoxy monomer is not particularly limited and is, for example, 50 g / eq. The epoxy equivalent means the mass of the epoxy monomer per equivalent of the epoxy group contained in the epoxy monomer.

[0082] Examples of epoxy monomers include monofunctional epoxy compounds such as n-butyl glycidyl ether, higher alcohol glycidyl ether, allyl glycidyl ether, 2-ethylhexyl glycidyl ether, phenyl glycidyl ether, cresyl glycidyl ether, p-sec-butylphenyl glycidyl ether, and t-butylphenyl glycidyl ether; diepoxy alkanes such as 1,5-hexadiene diepoxide, 1,7-octadiene diepoxide, and 1,9-decadiene diepoxide; (poly)ethylene glycol diglycidyl ether; (poly)propylene glycol diglycidyl ether; Examples of suitable epoxy compounds include polyfunctional epoxy compounds having an ether group, such as ethylene glycol diglycidyl ether, 1,4-butanediol diglycidyl ether, neopentyl glycol diglycidyl ether, 1,6-hexanediol diglycidyl ether, trimethylolpropane polyglycidyl ether, pentaerythritol polyglycidyl ether, and sorbitol polyglycidyl ether; and polyfunctional epoxy compounds having an amino group, such as N,N,N',N'-tetraglycidylmetaxylenediamine and 1,3-bis(N,N-diglycidylaminomethyl)cyclohexane.

[0083] The epoxy monomer may be an aromatic epoxy resin or a non-aromatic epoxy resin, depending on the case. Examples of aromatic epoxy resins include polyphenyl-based epoxy resins, epoxy resins containing a fluorene ring, epoxy resins containing triglycidyl isocyanurate, and epoxy resins containing a heteroaromatic ring (e.g., a triazine ring). Examples of polyphenyl-based epoxy resins include bisphenol A-type epoxy resins, brominated bisphenol A-type epoxy resins, bisphenol F-type epoxy resins, bisphenol AD-type epoxy resins, stilbene-type epoxy resins, biphenyl-type epoxy resins, bisphenol A novolac-type epoxy resins, cresol novolac-type epoxy resins, diaminodiphenylmethane-type epoxy resins, and tetrakis(hydroxyphenyl)ethane-based epoxy resins. Examples of non-aromatic epoxy resins include aliphatic glycidyl ether-type epoxy resins, aliphatic glycidyl ester-type epoxy resins, alicyclic glycidyl ether-type epoxy resins, alicyclic glycidyl amine-type epoxy resins, and alicyclic glycidyl ester-type epoxy resins.

[0084] The epoxy monomers can be used alone or in combination of two or more. When a monofunctional epoxy compound is used, it is preferably used in combination with another epoxy monomer containing two or more epoxy groups. The monofunctional epoxy compound can also be used as a reactive diluent to adjust the viscosity of the compounds used to form the reactant P1.

[0085] The epoxy monomer preferably includes a multifunctional epoxy compound having an ether group, such as ethylene glycol diglycidyl ether (EDE) or pentaerythritol tetraglycidyl ether (PETG). EDE and PETG have a low epoxy equivalent and can easily lower the glass transition temperature Tg of the polymer P. These epoxy compounds also tend to be low in cost. The epoxy monomer may include a multifunctional epoxy compound having an amino group, such as N,N,N',N'-tetraglycidylmetaxylenediamine or 1,3-bis(N,N-diglycidylaminomethyl)cyclohexane, in addition to or instead of the multifunctional epoxy compound having an ether group.

[0086] As described above, the polymer P as an amine polymer may contain a structural unit U1 derived from an epoxy monomer. When the polymer P is a reactant P1, the polymer P further contains a structural unit U2 derived from an amine monomer. The content of the structural unit U1 in the polymer P, particularly the reactant P1, is, for example, 20 wt% to 70 wt%. The content of the structural unit U2 in the polymer P, particularly the reactant P1, is, for example, 30 wt% or more, preferably 50 wt% or more. The upper limit of the content of the structural unit U2 is not particularly limited, and is, for example, 80 wt%.

[0087] The glass transition temperature Tg of the polymer P is not particularly limited, and may be, for example, 40 ° C or less, 30 ° C or less, 20 ° C or less, 15 ° C or less, 10 ° C or less, 5 ° C or less, 0 ° C or less, -1 ° C or less, less than -1 ° C, -2 ° C or less, -3 ° C or less, -4 ° C or less, -5 ° C or less, -6 ° C or less, -7 ° C or less, -8 ° C or less, -9 ° C or less, -10 ° C or less, -11 ° C or less, -12 ° C or less, -13 ° C or less, -14 ° C or less, or even -15 ° C or less. The lower the glass transition temperature Tg of the polymer P, the higher the rate at which the acidic gas adsorbent adsorbs the acidic gas. The lower limit of the glass transition temperature Tg of the polymer P may be, for example, -100 ° C or more, -50 ° C or more, -30 ° C or more, or even -20 ° C or more, from the viewpoint of ensuring sufficient acidic gas adsorption in the acidic gas adsorbent, heat resistance, and ease of preparation of the acidic gas adsorbent. In this specification, the glass transition temperature Tg is the midpoint glass transition temperature (T mg ) The polymer P generally corresponds to a thermosetting resin. The polymer P is preferably solid at 25°C, preferably in the range of 25°C to 80°C.

[0088] The weight-average molecular weight of the polymer P is not particularly limited and is, for example, 500 or more, preferably 1000 or more, more preferably 10000 or more, and even more preferably 100000 or more. The upper limit of the weight-average molecular weight of the polymer P is, for example, 10,000,000.

[0089] The acidic gas adsorbent preferably contains polymer P as a main component. In this specification, "main component" means the component that is contained in the acidic gas adsorbent in the largest amount by weight. The content of polymer P in the acidic gas adsorbent is, for example, 50 wt% or more, preferably 70 wt% or more, more preferably 90 wt% or more, and may be 95 wt% or more, or may be 99 wt% or more. The acidic gas adsorbent may be composed essentially of polymer P only. The higher the content of polymer P, the more the acidic gas adsorbent tends to improve its ability to adsorb acidic gases.

[0090] The acidic gas adsorbent may be substantially composed of polymer P alone, or may further contain other components in addition to polymer P. Examples of other components include reaction accelerators, plasticizers, pigments, dyes, antioxidants, conductive materials, antistatic agents, UV absorbers, flame retardants, and antioxidants. A reaction accelerator can be used when synthesizing polymer P. Examples of reaction accelerators include tertiary amines such as triethylamine and tributylamine; and imidazoles such as 2-phenol-4-methylimidazole, 2-ethyl-4-methylimidazole, and 2-phenol-4,5-dihydroxyimidazole. These reaction accelerators can accelerate the reaction for synthesizing reactant P1.

[0091] The weight ratio of nitrogen elements in the acidic gas adsorbent is, for example, 5 wt% or more, preferably 10 wt% or more. The higher this weight ratio, the more the acidic gas adsorbent tends to improve its ability to adsorb acidic gases. The upper limit of the weight ratio of nitrogen elements in the acidic gas adsorbent is not particularly limited, and is, for example, 30 wt%. Note that when all of the nitrogen elements contained in the acidic gas adsorbent are derived from amino groups, the weight ratio of the nitrogen elements can be considered to be the weight ratio of amino groups in the acidic gas adsorbent.

[0092] The shape of the acidic gas adsorbent is not particularly limited and may be, for example, a block, a sheet, a particle, etc. In this specification, the particle shape includes a spherical shape, an ellipsoidal shape, a scale shape, a fiber shape, etc.

[0093] The acidic gas adsorbent may have a porous structure. As an example, the acidic gas adsorbent may include a porous body S containing a polymer P. The porous body S is typically composed only of the polymer P. The shape of the porous body S may be, for example, a block, a sheet, or a particle. The acidic gas adsorbent may or may not include a porous resin sheet as the porous body S. The acidic gas adsorbent may or may not include a member other than the porous body S, such as a carrier for supporting the polymer P. When the acidic gas adsorbent does not include a carrier, the shape of the acidic gas adsorbent tends to be easily adjustable by cutting or machining.

[0094] The porous body S preferably has a three-dimensional network skeleton composed of polymer P. The three-dimensional network skeleton may contain polymer P as a main component, or may contain substantially only polymer P. The three-dimensional network skeleton may further contain components other than polymer P. As an example, in the porous body S, the above-mentioned three-dimensional network skeleton extends continuously. The pores contained in the porous body S are, for example, continuous pores formed continuously in a three-dimensional shape. The porous body S may have closed pores, or may have through pores that penetrate the porous body S.

[0095] The specific surface area of ​​the acid gas adsorbent (porous body S) is not particularly limited, and is, for example, 0.5 m 2 / g or more, and 1.0m 2 / g or more, 2.0m 2 / g or more, 3.0m 2 / g or more, 4.0m 2 / g or more, 5.0m 2 / g or more, 6.0m 2 / g or more, 7.0m 2 / g or more, 8.0m 2 / g or more, and even 9.0m 2 / g or more. The larger the specific surface area of ​​the acidic gas adsorbent, the faster the acidic gas adsorbent adsorbs the acidic gas. The upper limit of the specific surface area of ​​the acidic gas adsorbent is not particularly limited, and may be, for example, 100 m 2 / g. The specific surface area of ​​the acid gas adsorbent refers to the Brunauer-Emmett-Teller (BET) specific surface area determined by nitrogen gas adsorption. The specific surface area of ​​the acid gas adsorbent can be measured using a method in accordance with the provisions of JIS Z8830:2013.

[0096] From another aspect, the present invention provides: An acidic gas adsorbent comprising a polymer P having an amino group, The density d of the nitrogen element in the acid gas adsorbent is greater than 12.0 mmol / g; The specific surface area of ​​the acid gas adsorbent is 0.5m 2 / g or more, The acid gas adsorbent is provided in which the glass transition temperature of the polymer P is 40°C or lower. This acidic gas adsorbent preferably has the above-mentioned adsorption and desorption characteristics for carbon dioxide. As an example, the adsorption amounts a1 to a3, desorption amounts b1 to b2, 50°C desorption rate, 65°C desorption rate, and the like of the acidic gas adsorbent measured by the above-mentioned methods may satisfy the above-mentioned ranges.

[0097] The pore volume of the acidic gas adsorbent (porous body S) is not particularly limited, and may be, for example, 0.1 cm 3 / g or more, and 0.2cm 3 / g or more, 0.3cm 3 / g or more, 0.5cm 3 / g or more, 1.0cm 3 / g or more, and even 2.0 cm 3 The upper limit of the pore volume of the acidic gas adsorbent is not particularly limited, and may be, for example, 5.0 cm 3 / g, 4.0 cm 3 / g, and 3.0 cm 3 The pore volume of the acidic gas adsorbent can be measured by mercury intrusion porosimetry. Mercury intrusion porosimetry is performed using a commercially available pore size distribution analyzer (e.g., Autopore V9620 manufactured by Micromeritics) under an initial pressure of 21 kPa.

[0098] The average pore diameter of the acidic gas adsorbent (porous body S) is not particularly limited and may be, for example, 0.1 μm or more, 0.2 μm or more, 0.3 μm or more, or even 0.5 μm or more. The upper limit of the average pore diameter of the acidic gas adsorbent is not particularly limited and is, for example, 50 μm. In this specification, the average pore diameter of the acidic gas adsorbent means the median diameter measured by mercury intrusion porosimetry. Mercury intrusion porosimetry is performed using a commercially available pore size distribution analyzer (e.g., Autopore V9620 manufactured by Micromeritics) under an initial pressure of 21 kPa.

[0099] When the acidic gas adsorbent is particulate, the average particle size of the acidic gas adsorbent is not particularly limited and is, for example, 0.5 μm or more, preferably 1 μm or more, and may be 10 μm or more, 20 μm or more, or 30 μm or more. The average particle size of the acidic gas adsorbent may be 200 μm or less, 100 μm or less, or less than 75 μm. In this specification, the average particle size of the acidic gas adsorbent means the particle size (d50) corresponding to 50% cumulative volume in the particle size distribution measured by a laser diffraction particle sizer or the like.

[0100] (Method of manufacturing acid gas adsorbent) The method for producing an acidic gas adsorbent of the present embodiment preferably includes reacting a group of compounds including an amine monomer having a primary amino group to synthesize a polymer P. The group of compounds preferably further includes an epoxy monomer having an epoxy group.

[0101] The compound group may contain only an epoxy monomer E1 containing two epoxy groups, or may contain an epoxy monomer E2 containing three or more, for example, four, epoxy groups instead of or together with the epoxy monomer E1. When the compound group contains the epoxy monomers E1 and E2, the weight ratio E1 / E2 of the epoxy monomer E1 to the epoxy monomer E2 is not particularly limited and may be, for example, 3 / 7 to 8 / 2, 3 / 7 to 5 / 5, or even 3 / 7 to 4 / 6.

[0102] In this embodiment, the ratio E / A of the equivalent weight E of the epoxy group in the compound group to the equivalent weight A of the active hydrogen of the primary amino group in the compound group is preferably 1.00 or less. Specifically, it is preferable that the blending ratio of the amine monomer and the epoxy monomer is adjusted so that the ratio E / A is 1.00 or less. In the compound group, the ratio E / A is preferably 0.90 or less, and may be 0.50 or less, less than 0.50, 0.45 or less, 0.40 or less, 0.35 or less, or even 0.30 or less. The smaller the ratio E / A, the higher the ratio of primary amino groups in the polymer P and the higher the density d of nitrogen elements in the acidic gas adsorbent tends to be. From the viewpoint of ease of preparation of the acidic gas adsorbent, the lower limit of the ratio E / A may be, for example, 0.10 or more, 0.15 or more, or even 0.20 or more.

[0103] In this embodiment, it is preferable that the primary amino group of the amine monomer reacts with the epoxy group of the epoxy monomer in the compound group, causing a polymerization reaction or a crosslinking reaction to proceed. The reaction of the compound group can be carried out by applying energy to the compound group. The energy applied to the compound group is preferably thermal energy. As an example, the reaction of the compound group can be promoted by heating the compound group at a temperature of 40°C to 100°C. However, the energy applied to the compound group may also be light energy.

[0104] An acidic gas adsorbent having a porous structure can be prepared by the following method. First, the above-mentioned compounds are mixed with a porogen to prepare a mixture. The porogen is a solvent that can dissolve the monomers contained in the compounds and can also cause reaction-induced phase separation after the compounds react. Specific examples of porogens include cellosolves such as methyl cellosolve and ethyl cellosolve, esters such as ethylene glycol monomethyl ether acetate and propylene glycol monomethyl ether acetate, glycols such as polyethylene glycol, polypropylene glycol, polybutylene glycol, and polyoxyalkylene glycol, and ethers such as polyoxyethylene monomethyl ether and polyoxyethylene dimethyl ether. Specific examples of polyoxyalkylene glycols include poly(1,2-butanediol)-6 propylene glycol and polyoxypropylene diglyceryl ether. The porogen may be a polar solvent such as ethyl acetate, N,N-dimethylformamide (DMF), acetonitrile, ethanol, or isopropanol, a nonpolar solvent such as toluene, or a mixture thereof. The porogens can be used alone or in combination of two or more.

[0105] The mixture may further contain components other than the compounds, such as the above-mentioned reaction accelerators.

[0106] Next, the compounds are reacted in the mixture. For example, the mixture is filled into a mold and then heated to react the compounds. This results in a cured product containing the polymer P and the porogen. In this cured product, the polymer P and the porogen undergo phase separation to form a co-continuous structure.

[0107] Next, the porogen is extracted and removed from the cured product. This allows for the production of an acidic gas adsorbent with a porous structure. The porogen can be extracted by immersing the cured product in a solvent. Examples of the solvent include water, aliphatic hydrocarbon solvents, aromatic hydrocarbon solvents, aliphatic alcohol solvents, ester solvents, ether solvents, and halogen-containing organic solvents. Examples of aliphatic hydrocarbon solvents include n-hexane, cyclohexane, methylcyclohexane, n-heptane, n-octane, isooctane, petroleum ether, and benzine. Examples of aromatic hydrocarbon solvents include toluene, xylene, mesitylene, and benzene. Examples of aliphatic alcohol solvents include methanol, ethanol, isopropanol, butanol, cyclohexanol, ethylene glycol, propylene glycol, propylene glycol monomethyl ether, and diethylene glycol. Examples of ester solvents include ethyl acetate. Examples of ether solvents include diethyl ether, diisopropyl ether, dibutyl ether, ethylene glycol dimethyl ether, ethylene glycol diethyl ether, propylene glycol dimethyl ether, propylene glycol diethyl ether, diethylene glycol dimethyl ether, tetrahydrofuran, dioxane, and anisole. Examples of halogen-containing organic solvents include dichloromethane, chloroform, carbon tetrachloride, dichloroethane, and chlorobenzene. These solvents can be used alone or in combination of two or more.

[0108] When preparing a cured product, the faster the reaction rate of the compounds, the more finely the porogen tends to disperse in the cured product. By removing the porogen from a cured product in which the porogen is finely dispersed, an acidic gas adsorbent with a large specific surface area can be prepared. The reaction rate of the compounds varies depending on the type and blending ratio of the monomers contained in the compounds. For example, the reaction rate of the compounds tends to be high when an epoxy monomer E2 containing three or more, e.g., four, epoxy groups is used, or when polyethyleneimine with a high weight-average molecular weight is used as the amine monomer.

[0109] (Applications for acid gas adsorbents) The acidic gas adsorbent of this embodiment can adsorb acidic gases such as carbon dioxide, hydrogen sulfide, carbonyl sulfide, sulfur oxides (SOx), hydrogen cyanide, and nitrogen oxides (NOx), with carbon dioxide being preferred.

[0110] The acidic gas adsorbent can be used by the following method. First, a mixed gas containing an acidic gas is contacted with the acidic gas adsorbent. The mixed gas preferably contains other gases in addition to the acidic gas. Examples of other gases include non-polar gases such as hydrogen and nitrogen, and inert gases such as helium, with nitrogen being preferred. The mixed gas is typically atmospheric air. The mixed gas may also be off-gas from a chemical plant or thermal power plant.

[0111] The temperature of the mixed gas is, for example, room temperature (23°C). The concentration of the acidic gas in the mixed gas is not particularly limited, and is, for example, 0.01 vol% (100 volppm) or more, preferably 0.04 vol% (400 volppm) or more, and may be 1.0 vol% or more, under standard conditions (0°C, 101 kPa). The upper limit of the carbon dioxide concentration in the mixed gas is not particularly limited, and is, for example, 10 vol% under standard conditions. The pressure of the mixed gas is typically equal to atmospheric pressure in the environment in which the acidic gas adsorbent is used. However, the mixed gas to be contacted with the acidic gas adsorbent may be pressurized.

[0112] The acidic gas adsorbent that has come into contact with the mixed gas adsorbs the acidic gas contained in the mixed gas. The operation of bringing the mixed gas into contact with the acidic gas adsorbent is preferably carried out until the adsorption of the acidic gas by the acidic gas adsorbent reaches equilibrium.

[0113] Next, the acidic gas adsorbent that has adsorbed the acidic gas is regenerated. The regeneration can be performed by heating the acidic gas adsorbent. The heating temperature of the acidic gas adsorbent is, for example, 50 to 80°C. The acidic gas adsorbent may be heated under a reduced pressure or a vacuum. By heating the acidic gas adsorbent, the acidic gas is desorbed from the acidic gas adsorbent. This regenerates the acidic gas adsorbent, allowing it to be reused. The acidic gases, particularly carbon dioxide, desorbed from the acidic gas adsorbent can be used as raw materials for chemical synthesis or as dry ice. The adsorption of acidic gases by the acidic gas adsorbent and the regeneration of the acidic gas adsorbent can be performed using the measuring device 20 (acidic gas adsorption device) described above.

[0114] <Embodiment of the structure> 2A, the structure 15 of this embodiment includes the above-described acidic gas adsorbent 10 and ventilation paths 14. The structure 15 is typically a honeycomb structure having a plurality of ventilation paths 14 extending in the same direction.

[0115] The acid gas adsorbent 10 included in the structure 15 typically has a sheet shape. The structure 15 may or may not include a support for supporting the acid gas adsorbent 10 together with the acid gas adsorbent 10.

[0116] The structure 15 preferably includes an adsorbent unit U in which a corrugated acidic gas adsorbent 10A and a flat-plate acidic gas adsorbent 10B are stacked. In the acidic gas adsorbent 10A, a plurality of peaks 12 and a plurality of valleys 13 are alternately arranged. Air passages 14 are formed between the peaks 12 or valleys 13 of the acidic gas adsorbent 10A and the acidic gas adsorbent 10B. In this embodiment, the direction x is the direction (wave direction) in which the plurality of peaks 12 and the plurality of valleys 13 of the acidic gas adsorbent 10A are alternately arranged. The direction y is the stacking direction of the acidic gas adsorbents 10A and 10B in the adsorbent unit U. The direction z is perpendicular to the directions x and y, and is the direction in which the air passages 14 extend.

[0117] The structure 15 preferably includes a plurality of adsorbent units U. The number of adsorbent units U in the structure 15 is not particularly limited and may be, for example, 2 to 100. In the structure 15, the plurality of adsorbent units U are stacked in the direction y so that a plurality of acidic gas adsorbents 10A and a plurality of acidic gas adsorbents 10B are arranged alternately. By stacking the plurality of adsorbent units U, the structure 15 has a block shape.

[0118] The ventilation paths 14 are through-holes that penetrate the structure 15 in direction z. The ventilation paths 14 are surrounded by the acidic gas adsorbents 10A and 10B. In the structure 15, the acidic gas moves in direction z through the ventilation paths 14 and is efficiently adsorbed by the acidic gas adsorbents 10A and 10B.

[0119] In the structure 15, the smaller the thickness of the acidic gas adsorbents 10A and 10B, the larger the cross-sectional area of ​​the ventilation path 14 can be adjusted. A structure 15 with a large cross-sectional area of ​​the ventilation path 14 is suitable for reducing pressure loss that occurs when the structure 15 comes into contact with acidic gas. A structure 15 with reduced pressure loss can reduce the power of the fan used to move the acidic gas. Note that if the amount of amino group substance per unit volume of the acidic gas adsorbent 10 is large, the acidic gas adsorbent 10 tends to be able to sufficiently adsorb acidic gases even when the thickness of the acidic gas adsorbent 10 is small.

[0120] <Modification of structure> The shape of the structure 15 including the acid gas adsorbent 10 is not limited to that shown in Fig. 2A. The structure 16 shown in Fig. 2B has a shape in which one adsorbent unit U is wound around a central tube 80. Except for this, the configuration of the structure 16 is the same as that of the structure 15.

[0121] The structure 16 has a cylindrical shape. In the structure 16, the multiple peaks 12 and the multiple valleys 13 of the acidic gas adsorbent 10A are alternately arranged in the circumferential direction of the structure 16. The ventilation paths 14 formed between the peaks 12 or valleys 13 of the acidic gas adsorbent 10A and the acidic gas adsorbent 10B penetrate the structure 16 in the extension direction of the central tube 80. In the structure 16, the acidic gas moves through the ventilation paths 14 in the extension direction of the central tube 80 and is efficiently adsorbed by the acidic gas adsorbents 10A and 10B.

[0122] <Another variation of the structure> The structure does not necessarily have to include the corrugated acid gas adsorbent 10A, and does not necessarily have to be a honeycomb structure like structures 15 and 16. Structure 17 shown in FIG. 2C includes only a flat-plate acid gas adsorbent 10B as the acid gas adsorbent 10. Specifically, structure 17 includes a plurality of acid gas adsorbents 10B, which are arranged with gaps between them. The gap between two acid gas adsorbents 10B functions as a ventilation path 14.

[0123] The structure 17 may further include a fixing member 81 that fixes the plurality of acidic gas adsorbents 10B to ensure the above-mentioned ventilation path 14. The fixing member 81 is, for example, a rod. As an example, each of the plurality of acidic gas adsorbents 10B has a through-hole that penetrates the acidic gas adsorbent 10B in the thickness direction, and a rod serving as the fixing member 81 is inserted into the through-hole of each acidic gas adsorbent 10B to fix the plurality of acidic gas adsorbents 10B. The rod serving as the fixing member 81 may be a bolt having a male thread formed on its side. In this case, the ventilation path 14 can be more reliably ensured by threading a nut onto the bolt at a position between two acidic gas adsorbents 10B. In this example, the nut functions as a spacer.

[0124] In the example of Fig. 2C, each of the plurality of acidic gas adsorbents 10B has a rectangular shape in a plan view, and through-holes are formed near the four corners. Furthermore, the acidic gas adsorbent 10C includes four fixing members 81, which are inserted into four through-holes formed in the four corners of the acidic gas adsorbent 10B, respectively. However, the number and positions of the through-holes formed in the acidic gas adsorbent 10B and the number of fixing members 81 are not limited to those shown in the example of Fig. 2C.

[0125] In the structure 17, the acid gas is efficiently adsorbed by the two acid gas adsorbents 10B while moving through the ventilation path 14 between the two acid gas adsorbents 10B.

[0126] <Embodiment of Acid Gas Recovery Device> 3A , the acidic gas recovery apparatus 100A of the present embodiment includes the above-described acidic gas adsorbent 10 and a medium path 85. In the acidic gas recovery apparatus 100A, a heat medium 86 that heats the acidic gas adsorbent 10 passes through the medium path 85 during a desorption operation in which the acidic gas adsorbed by the acidic gas adsorbent 10 is desorbed from the acidic gas adsorbent 10.

[0127] The acidic gas adsorbent 10 included in the acidic gas recovery system 100A typically has a sheet shape. The acidic gas recovery system 100A may or may not include a support for supporting the acidic gas adsorbent 10 together with the acidic gas adsorbent 10.

[0128] The acidic gas recovery apparatus 100A preferably includes a plurality of acidic gas adsorbents 10. The plurality of acidic gas adsorbents 10 may be arranged with a gap therebetween, and the gap between two acidic gas adsorbents 10 may function as the ventilation path 14. In the acidic gas recovery apparatus 100A, the configurations of the acidic gas adsorbents 10 and the ventilation path 14 may be the same as those described above for the structures 15 to 17.

[0129] In the acidic gas recovery apparatus 100A, the medium path 85 is preferably configured with piping made of a metal such as copper, specifically a heat transfer tube. In the acidic gas recovery apparatus 100A, the medium path 85 may penetrate the acidic gas adsorbent 10 in the thickness direction of the acidic gas adsorbent 10. Specifically, the acidic gas adsorbent 10 has through-holes that penetrate the acidic gas adsorbent 10 in the thickness direction, and the medium path 85 is inserted into the through-holes of the acidic gas adsorbent 10. The acidic gas recovery apparatus 100A typically has a structure similar to that of a fin-tube heat exchanger that includes heat transfer fins and heat transfer tubes that penetrate the heat transfer fins.

[0130] The medium path 85 may have a U-shape and be inserted into two through-holes formed in the acidic gas adsorbent 10. The number of through-holes formed in the acidic gas adsorbent 10 and the number of medium paths 85 are not limited to those shown in FIG. 3A . As an example, four or more through-holes may be formed in the acidic gas adsorbent 10, and two or more U-shaped medium paths 85 may be inserted into the through-holes of the acidic gas adsorbent 10.

[0131] As described above, the medium path 85 functions as a path for the heat medium 86 that heats the acid gas adsorbent 10 during the desorption operation. However, the medium path 85 can also be used as a path for the cooling medium that cools the acid gas adsorbent 10 after the desorption operation. In other words, the medium path 85 may serve as both the path for the heat medium 86 and the path for the cooling medium.

[0132] The acidic gas recovery apparatus 100A further includes a casing (not shown) that houses the acidic gas adsorbent 10 and the medium path 85. The casing preferably has a mixed gas inlet for sending a mixed gas containing acidic gas into the casing. The casing may further have a desorption gas outlet for discharging the desorbed gas desorbed from the acidic gas adsorbent 10 to the outside of the casing during desorption operation, and a purge gas inlet for sending a purge gas into the casing. Note that in the casing, the mixed gas inlet may also serve as the purge gas inlet. Furthermore, the casing may have a medium inlet for sending a heating medium 86 or a cooling medium to the medium path 85, and a medium outlet for discharging the heating medium 86 or the cooling medium from the medium path 85.

[0133] [Operation method of acid gas recovery unit] The acidic gas recovery apparatus 100A preferably repeatedly performs an adsorption operation in which the acidic gas is adsorbed onto the acidic gas adsorbent 10, and a desorption operation in which the acidic gas adsorbed by the acidic gas adsorbent 10 is desorbed from the acidic gas adsorbent 10. By performing the adsorption operation and the desorption operation using the acidic gas recovery apparatus 100A, acidic gas can be recovered.

[0134] (Adsorption operation) The adsorption operation of the acidic gas recovery apparatus 100A is performed as follows. First, a mixed gas containing acidic gas is sent into the casing through the mixed gas inlet. Examples of the mixed gas include those described above. The mixed gas comes into contact with the acidic gas adsorbent 10 while traveling through the ventilation path 14. This causes the acidic gas adsorbent 10 to adsorb the acidic gas contained in the mixed gas. The adsorption operation is preferably performed until the adsorption of acidic gas by the acidic gas adsorbent 10 reaches equilibrium.

[0135] (Desorption operation) The desorption operation of the acidic gas recovery apparatus 100A is performed as follows. First, purge gas is sent into the interior of the casing through the purge gas inlet, and the purge gas is discharged to the outside of the casing through the desorbed gas outlet. This operation discharges the mixed gas remaining inside the casing to the outside of the casing, filling the inside of the casing with purge gas. For example, water vapor gas or a gas containing a high concentration of acidic gas such as carbon dioxide can be used as the purge gas. Note that instead of or in addition to the operation of sending the purge gas into the casing, an operation of depressurizing the inside of the casing may be performed. This depressurization operation can be performed using a pressure reducing device connected to the desorbed gas outlet of the casing.

[0136] Next, while the purge gas is being supplied to the inside of the casing, the heat transfer medium 86 is sent to the medium path 85. Hot water, high-temperature gas, or the like can be used as the heat transfer medium 86. Specific examples of gases contained in the high-temperature gas include chlorofluorocarbons, carbon dioxide, air, and water vapor. The heat transfer medium 86 can be prepared, for example, by using waste heat, a heat pump, or self-heat recovery.

[0137] By sending the heat medium 86 to the medium path 85, heat exchange occurs between the heat medium 86 and the acidic gas adsorbent 10 via the medium path 85, and the acidic gas adsorbent 10 is heated. The heating temperature of the acidic gas adsorbent 10 is, for example, 50 to 80°C. As a result, the acidic gas is desorbed from the acidic gas adsorbent 10. The desorbed gas desorbed from the acidic gas adsorbent 10 is discharged from a desorbed gas outlet together with a purge gas. This allows the acidic gas to be recovered. Note that, if the purge gas contains water vapor, the water vapor can be removed by cooling the purge gas discharged from the desorbed gas outlet and condensing the water vapor. Note that it is not necessarily necessary to use the heat medium 86 to heat the acidic gas adsorbent 10. If a support supporting the acidic gas adsorbent 10 functions as a planar heater, the acidic gas adsorbent 10 may be heated by passing electricity through the support.

[0138] The acidic gas recovery system 100A is configured so that the heat transfer medium 86 does not come into direct contact with the desorbed gas during desorption operation. This acidic gas recovery system 100A can efficiently recover acidic gases. The recovered acidic gases, particularly carbon dioxide, can be used as raw materials for chemical synthesis or as dry ice.

[0139] (Preparatory run) The acidic gas recovery apparatus 100A may perform a preparatory operation for the adsorption operation after the desorption operation. The preparatory operation is performed as follows. First, the supply of purge gas to the inside of the casing is stopped, and the heat medium 86 is discharged from the medium path 85. Next, a cooling medium is sent to the medium path 85. Antifreeze or the like can be used as the cooling medium. Heat exchange occurs between the cooling medium and the acidic gas adsorbent 10 via the medium path 85, and the acidic gas adsorbent 10 is cooled. The acidic gas adsorbent 10 is preferably cooled to room temperature (25°C). After the acidic gas adsorbent 10 has cooled, the cooling medium is discharged from the medium path 85, completing preparation for the adsorption operation.

[0140] <Modification of Acid Gas Recovery Device> The acid gas recovery apparatus is not limited to the one shown in FIG. 3A. In the acid gas recovery apparatus 100B shown in FIG. 3B, a medium path 85 is formed between two acid gas adsorbents 10. In detail, in the acid gas recovery apparatus 100B, among the multiple gaps formed between the multiple acid gas adsorbents 10, some of the gaps function as the medium path 85, and the remaining gaps function as the ventilation path 14. The medium path 85 and the ventilation path 14 are alternately arranged along the arrangement direction of the multiple acid gas adsorbents 10. The acid gas recovery apparatus 100B typically has a structure similar to that of a plate heat exchanger in which multiple heat transfer plates are stacked.

[0141] The acid gas recovery apparatus 100B preferably includes the acid gas adsorbent 10 and a support supporting the acid gas adsorbent 10. In the acid gas recovery apparatus 100B, the acid gas adsorbent 10 preferably faces the ventilation path 14, and the support faces the medium path 85. In the acid gas recovery apparatus 100B, a spacer 95 is disposed in the ventilation path 14, and a spacer (not shown) is also disposed in the medium path 85. These spacers are configured to secure the ventilation path 14 and the medium path 85, introduce appropriate fluids into each path, and prevent fluids from leaking into other paths. In FIG. 3B , the ventilation path 14 may be connected to the external space of the acid gas recovery apparatus 100B at both the back and front of the page, thereby allowing the mixed gas to be introduced into the ventilation path 14 from the external space. Furthermore, during desorption operation of the acid gas recovery apparatus 100B, a member may be disposed between the ventilation path 14 and the external space to block the connection therebetween.

[0142] The acidic gas recovery apparatus 100B further includes a restraining member 90 that restrains the plurality of acidic gas adsorbents 10. The restraining member 90 preferably includes a pair of plate members 91a, 91b, a rod 92, and a fixing member 93. The plate members 91a and 91b are aligned in the arrangement direction of the plurality of acidic gas adsorbents 10, and sandwich the plurality of acidic gas adsorbents 10. The plate members 91a and 91b allow pressure to be applied to the plurality of acidic gas adsorbents 10 in the arrangement direction. The plate members 91a and 91b may be formed with the desorbed gas outlet, purge gas inlet, medium inlet, medium outlet, etc., as described above for the acidic gas recovery apparatus 100A.

[0143] A through hole is formed in each of the plate members 91a and 91b, and the rod 92 is inserted into the through hole of the plate members 91a and 91b. The rod 92 may be a bolt with a male thread formed on its side. The fixing member 93 may fix one of the plate members 91a and 91b and the rod 92 to each other. The fixing member 93 is typically a nut with a female thread that can be threaded onto the rod 92. The restraining member 90 has a fixing member 93a that fixes the plate member 91a and the rod 92 to each other, and a fixing member 93b that fixes the plate member 91b and the rod 92 to each other.

[0144] In the example of Fig. 3B, two rods 92 are each fixed by a fixing member 93. However, the number of rods 92 and the like are not limited to the example of Fig. 3B.

[0145] The acidic gas recovery system 100B can be operated in the same manner as the acidic gas recovery system 100A described above. In the acidic gas recovery system 100B, a medium path 85 is formed between two acidic gas adsorbents 10. With this configuration, during desorption operation, the heat transfer medium passes through the medium path 85, thereby allowing the entire acidic gas adsorbent 10 to be uniformly heated.

[0146] Furthermore, unlike the acidic gas recovery system 100A, the acidic gas recovery system 100B is configured so that the ventilation path 14 does not interfere with the medium path 85. Therefore, in the acidic gas recovery system 100B, the pressure loss caused by the mixed gas passing through the ventilation path 14 during adsorption operation tends to be small.

[0147] The acidic gas recovery apparatus 100B allows components such as the acidic gas adsorbent 10 to be easily removed compared to the acidic gas recovery apparatus 100A. By removing the acidic gas adsorbent 10 from the acidic gas recovery apparatus 100B, it is easy to replace the acidic gas adsorbent 10. Furthermore, by removing each component of the acidic gas recovery apparatus 100B, it is easy to perform maintenance such as cleaning on each component. [Example]

[0148] The present invention will be described in more detail below with reference to examples and comparative examples, but the present invention is not limited thereto.

[0149] Example 1 First, 1.06 g of poly(1,2-butanediol)-6 propylene glycol (NOF Corporation, Uniol (registered trademark) PB-500) and 1.06 g of a butylene glycol / propylene glycol copolymer (NOF Corporation, Uniol (registered trademark) PB-700) were added to a 6 mL screw tube bottle (AS ONE Corporation). 0.91 g of ethylene glycol diglycidyl ether (Nagase ChemteX Corporation, EX-810) was dissolved in the resulting mixture to prepare a mixture of epoxy monomer and porogen.

[0150] Next, 2.02 g of polyethyleneimine (Epomin SP-012, manufactured by Nippon Shokubai Co., Ltd.) was added to this mixture to prepare a mixture of epoxy monomer, amine monomer, and porogen. In this mixture, the ratio E / A of the equivalent weight E of the epoxy group contained in the epoxy monomer to the equivalent weight A of the active hydrogen of the primary amino group contained in the amine monomer was 0.3.

[0151] Next, the mixture was shaken for 2 minutes using a tabletop shaker (Angel Vibrator Digital 60 Hz) set to intensity 5. The mixture was then allowed to stand in a thermostatic chamber at 80°C for 2 hours to harden. This resulted in a block-shaped cured product containing polymer P having amino groups. The cured product was removed from the screw cap and cut into approximately 3 mm square pieces. The cured product was then immersed in ethyl acetate at 60°C for 1 hour, and this operation was repeated twice with each liquid change. This removed the porogen from the cured product, forming a porous body containing polymer P. The porous body was dried at 60°C for 1 hour and then vacuum-dried for another 2 hours to obtain the acidic gas adsorbent of Example 1.

[0152] Examples 2 to 11 The acidic gas adsorbents of Examples 2 to 11 were obtained in the same manner as in Example 1, except that the types and amounts of raw materials were changed as shown in Table 1.

[0153] (Comparative Example 1) First, 2.63 g of polypropylene glycol (ADEKA Corporation, Adeka Polyether P-400) and 0.36 g of polyethylene glycol (Sigma-Aldrich Corporation, average molecular weight 200) were added to a 6 mL screw cap bottle (AS ONE Corporation). 1.58 g of bisphenol A epoxy resin (Mitsubishi Chemical Corporation, JER828) was dissolved in the resulting mixture to prepare a mixture of epoxy monomer and porogen.

[0154] Next, 0.60 g of triethylenetetramine was added to the mixture to prepare a mixture of epoxy monomer, amine monomer, and porogen. In this mixture, the ratio E / A (the equivalent weight E of the epoxy group contained in the epoxy monomer to the equivalent weight A of the active hydrogen of the primary amino group contained in the amine monomer) was 0.5.

[0155] Next, the mixture was shaken for 2 minutes using a tabletop shaker (Angel Vibrator Digital 60 Hz) set to intensity 5. The mixture was then allowed to stand in a thermostatic chamber at 80°C for 4 hours to harden. This resulted in a block-shaped cured product containing a polymer having amino groups. The cured product was removed from the screw cap and cut into approximately 3 mm square pieces. The cured product was then immersed in isopropyl alcohol at 60°C for 1 hour, a process repeated twice with liquid changes. The cured product was then immersed in ultrapure water at 60°C for 1 hour, a process repeated twice with liquid changes. The cured product was then immersed in methanol at room temperature for 1 hour. The cured product was air-dried at room temperature for 12 hours and then vacuum-dried at 60°C for 8 hours to obtain an acidic gas adsorbent of Comparative Example 1.

[0156] (Comparative Examples 2 to 3) Acidic gas adsorbents of Comparative Examples 2 and 3 were obtained in the same manner as in Comparative Example 1, except that the types and amounts of raw materials were changed as shown in Table 1.

[0157] [Density of nitrogen element] The density d of nitrogen element of the produced acidic gas adsorbent was measured by the above-mentioned method. VarioELIII manufactured by Elementar was used as the CHN elemental analyzer.

[0158] [Specific surface area] The specific surface area of ​​the prepared acidic gas adsorbent was measured according to the method specified in JIS Z8830: 2013. A specific surface area measuring device (product name "BERSORP-mini" manufactured by Microtrack-Bell Corporation) was used for the measurement.

[0159] [Glass transition temperature Tg] The glass transition temperature (Tg) of the polymer contained in the prepared acidic gas adsorbent was measured using the following method. First, approximately 5 mg of the acidic gas adsorbent was placed in a differential scanning calorimeter (TA Instruments, DSC2500). Using this device, the temperature was increased from 30°C to 200°C at a heating rate of 10°C / min under a nitrogen atmosphere and held at that temperature for 1 minute. Next, the temperature was decreased to -50°C at a heating rate of 10°C / min, held at that temperature for 1 minute, and then further increased to 200°C at a heating rate of 10°C / min. In the DSC curve during the second heating, the first baseline before the specific heat change appeared, the second baseline after the specific heat change appeared, and the tangent passing through the point of maximum slope in the bending portion due to the specific heat change were identified. The intermediate temperature between the intersection of the first baseline and the tangent and the intersection of the second baseline and the tangent was determined as the glass transition temperature (Tg).

[0160] [Near infrared spectroscopy] In Examples 1 to 6, the polymer contained in the prepared acidic gas adsorbent was subjected to near-infrared spectroscopy (NIR) by the following method. First, a transparent test piece was prepared by press-molding the polymer. Next, the test piece was set in an infrared spectrophotometer (BRUKER, INVENIO S, HYPERION 3000) so that the transparent portion was analyzed. Spectral data was obtained by performing NIR on the test piece. In the spectral data, the peak at a wave number of 4930 cm -1 Peak intensity I of the absorption peak present in the vicinity A , and wave number 6500 cm -1 Peak intensity I of the absorption peak present in the vicinity B Identify the ratio I A / I B was calculated.

[0161] Fig. 4 shows near-infrared absorption spectra showing the results of NIR on the polymers prepared in Examples 1 and 2. As can be seen from Fig. 4, the near-infrared absorption spectrum shows a peak at a wave number of 6500 cm -1 Absorption peaks due to primary and secondary amino groups are observed around the wavenumber of 4930 cm -1 An absorption peak due to a primary amino group was observed around this point.

[0162] [Amount of carbon dioxide adsorbed] For the acidic gas adsorbents prepared in the examples, the adsorption amounts a1 to a3 and the desorption amount b1 were measured by the method described above. Furthermore, based on these results, the ratio of the desorption amount b1 (mmol / g) to the adsorption amount a1 (mmol / g) (65°C desorption rate) was calculated. For the acidic gas adsorbents prepared in the comparative examples, the adsorption amount a1 was measured by the method described above.

[0163] [Table 1]

[0164] The abbreviations in Table 1 are as follows: EDE: Ethylene glycol diglycidyl ether (Nagase ChemteX Corporation, EX-810) JER828: Bisphenol A epoxy resin (Mitsubishi Chemical Corporation, JER828) PETG: Pentaerythritol tetraglycidyl ether (Showa Denko K.K., Showfree (registered trademark) PETG) TX: N,N,N',N'-tetraglycidylmetaxylenediamine (Mitsubishi Gas Chemical Company, Inc., TETRAD-X) TC: 1,3-bis(N,N-diglycidylaminomethyl)cyclohexane (manufactured by Mitsubishi Gas Chemical Company, Inc., TETRAD-C) PEI1200: Polyethyleneimine (Nippon Shokubai Co., Ltd., Epomin SP-012, weight-average molecular weight approximately 1200) PEI300: Polyethyleneimine (Nippon Shokubai Co., Ltd., Epomin SP-003, weight-average molecular weight approximately 300) PEI1800: Polyethyleneimine (Nippon Shokubai Co., Ltd., Epomin SP-018, weight-average molecular weight approximately 1800) TETA: Triethylenetetramine (Tosoh Corporation) PB-500: Poly(1,2-butanediol)-6 propylene glycol (NOF Corporation, Uniol (registered trademark) PB-500) P-400: Polypropylene glycol (ADEKA Corporation, Adeka Polyether P-400) PB-700: a copolymer of butylene glycol and propylene glycol (NOF Corporation, Uniol (registered trademark) PB-700) DGP-700: Polyoxypropylene diglyceryl ether (NOF Corporation, Unilube (registered trademark) DGP-700) PEG: polyethylene glycol (Sigma-Aldrich, average molecular weight 200)

[0165] The following Table 2 shows the safety indexes for handling the amine monomers used in the examples and comparative examples.

[0166] [Table 2]

[0167] [Table 3]

[0168] As can be seen from Table 3, the acidic gas adsorbents of the Examples had a large nitrogen element density d, and also had large adsorption amounts a1 and desorption amounts b1. In particular, Examples 1 to 6, in which the ratio E / A was adjusted to less than 0.50, had a larger nitrogen element density d and larger adsorption amounts a1 than Examples 7 to 11. It can be said that the acidic gas adsorbents of the Examples are suitable for adsorbing and desorbing acidic gases under relatively mild conditions.

[0169] In addition, when comparing examples (Examples 1 to 2 and Examples 3 to 5) in which the same type of monomer was used, the ratio I determined by NIR decreased as the ratio E / A decreased. A / I B This result shows that the ratio of primary amino groups in the polymer increases as the ratio E / A decreases. [Industrial Applicability]

[0170] The acidic gas adsorbent of this embodiment can adsorb carbon dioxide in the atmosphere.

Claims

1. An acidic gas adsorbent comprising a polymer having an amino group, the polymer comprises a structural unit derived from an epoxy monomer and a structural unit derived from an amine monomer, the amine monomer comprises an aliphatic polyamine; The density of nitrogen element in the acidic gas adsorbent is 12.2 mmol / g or more, When the following adsorption test A1 is performed, the adsorption amount a1 of carbon dioxide is 0.35 mmol / g or more, An acidic gas adsorbent, wherein when the following desorption test B1 is performed, the amount b1 of carbon dioxide desorption is 0.2 mmol / g or more. Adsorption test A1: A mixed gas composed of carbon dioxide, nitrogen, and water vapor was continuously fed into a container containing the acidic gas adsorbent for 15 hours, where the carbon dioxide concentration in the mixed gas was 400 vol ppm, the mixed gas temperature was 23°C, and the humidity was 50% RH. Desorption test B1: While continuing to feed the mixed gas into the container, the acidic gas adsorbent after the adsorption test A1 is heated at 65°C for 1.5 hours.

2. 2. The acidic gas adsorbent according to claim 1, wherein the adsorption amount a1 is 2.4 mmol / g or more.

3. The acidic gas adsorbent according to claim 1 , wherein the desorption amount b1 is 2.0 mmol / g or more.

4. 2. The acidic gas adsorbent according to claim 1, wherein when the following adsorption test A2 is carried out, the carbon dioxide adsorption amount a2 is 0.8 mmol / g or more. Adsorption test A2: The mixed gas was continuously fed into the vessel for 1 hour.

5. 2. The acidic gas adsorbent according to claim 1, wherein when the following adsorption test A3 is carried out, the adsorption amount a3 of carbon dioxide is 1.9 mmol / g or more. Adsorption test A3: The mixed gas was continuously fed into the vessel for 4 hours.

6. An acidic gas adsorbent comprising a polymer having an amino group, the polymer comprises a structural unit derived from an epoxy monomer and a structural unit derived from an amine monomer, the amine monomer comprises an aliphatic polyamine; The density of nitrogen element in the acidic gas adsorbent is 12.2 mmol / g or more, The specific surface area of ​​the acid gas adsorbent is 0.5 m 2 / g or more, The polymer has a glass transition temperature of 40°C or lower.

7. The acidic gas adsorbent according to claim 1 or 6, wherein the polymer has a glass transition temperature of less than -1°C.

8. The acidic gas adsorbent according to claim 1 or 6, wherein the density of nitrogen element in the acidic gas adsorbent is 13.0 mmol / g or more.

9. 10. The acid gas adsorbent of claim 1 or 6, wherein the amine monomer comprises polyethyleneimine.

10. The acidic gas adsorbent according to claim 1 or 6, which has a porous structure.

11. The acidic gas adsorbent according to claim 1 or 6; A ventilation path; A structure comprising:

12. an adsorption section having a gas inlet and a gas outlet; An acidic gas adsorption device, wherein the adsorption section contains the acidic gas adsorbent according to claim 1 or 6.

13. A method for producing the acidic gas adsorbent according to claim 1 or 6, The production method is a method for producing an acidic gas adsorbent, which comprises reacting a group of compounds including the amine monomer having a primary amino group to synthesize the polymer.

14. The group of compounds further includes the epoxy monomer containing an epoxy group, The method according to claim 13, wherein the ratio E / A of the equivalents E of the epoxy groups in the compound group to the equivalents A of the active hydrogens of the primary amino groups in the compound group is less than 0.50.

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