System for removing nitrogen oxides and / or sulfur oxides, method for removing nitrogen oxides and / or sulfur oxides, system for separating and capturing carbon dioxide, and method for separating and capturing carbon dioxide

Abstract

A method for removing nitrogen oxides and / or sulfur oxides is provided, by which nitrogen oxides and / or sulfur oxides are removed from a gas to be treated which contains both carbon dioxide and the nitrogen oxides and / or sulfur oxides. The method for removing nitrogen oxides and / or sulfur oxides includes a gas supply step in which the gas to be treated is supplied to an anion-exchanger packed tower packed with an anion exchanger.

Description

Nitrogen oxide and / or sulfur oxide removal system, nitrogen oxide and / or sulfur oxide removal method, carbon dioxide separation and capture system, and carbon dioxide separation and capture method

[0001] The present disclosure relates to a nitrogen oxide and / or sulfur oxide removal system, a nitrogen oxide and / or sulfur oxide removal method, a carbon dioxide separation and recovery system, and a carbon dioxide separation and recovery method.

[0002] In recent years, attention has been focused on technology that separates and captures carbon dioxide, a cause of global warming, from large-scale sources such as thermal power plants and steelworks blast furnaces before it is released into the atmosphere.

[0003] As such a technology, for example, research and development is being conducted on separation and recovery of carbon dioxide using a facilitated transport membrane (see, for example, Patent Document 1).

[0004] Furthermore, carbon dioxide capture technologies typified by absorption, adsorption, and membrane separation often use amine compounds as carbon dioxide carriers. When using an amine compound as a carbon dioxide carrier, in order to efficiently react the amine compound with carbon dioxide, it has been considered to install a nitrogen oxide and / or sulfur oxide removal system in a stage prior to separating and capturing carbon dioxide, thereby removing the nitrogen oxide and / or sulfur oxide (see, for example, Patent Document 2). The use of such technologies often requires large-scale facilities, which tends to increase the facility costs and operation and management burden.

[0005] JP 2009-185118 A JP 3-293017 A

[0006] In view of the above circumstances, it is desirable to develop a method for more simply removing nitrogen oxides and / or sulfur oxides. Therefore, an object of the present disclosure is to provide a method for simply removing nitrogen oxides and / or sulfur oxides.

[0007] As a result of intensive research aimed at solving the above-mentioned problems, the inventors of the present disclosure have found that nitrogen oxides and sulfur oxides in a gas to be treated can be easily removed by using a packed column packed with an anion exchanger, and have thus completed the present disclosure.

[0008] [1] A method for removing nitrogen oxides and / or sulfur oxides from a gas to be treated containing nitrogen oxides and / or sulfur oxides and carbon dioxide, comprising a gas supply step of supplying the gas to be treated to an anion exchanger packed column packed with an anion exchanger. [2] The method for removing nitrogen oxides and / or sulfur oxides according to [1], comprising a temperature adjustment step of controlling the temperature of the anion exchanger within a range of 20° C. to 100° C. [3] The method for removing nitrogen oxides and / or sulfur oxides according to [1] or [2], comprising a condition control step of controlling one or more conditions selected from the group consisting of flow rate, temperature, and humidity of the gas to be treated. [4] A system for removing nitrogen oxides and / or sulfur oxides from a gas to be treated that contains nitrogen oxides and / or sulfur oxides and carbon dioxide, comprising: a condition control unit that controls one or more conditions selected from the group consisting of a flow rate, a temperature, and a humidity of the gas to be treated; an anion exchanger packed tower that is filled with an anion exchanger and to which the gas to be treated, the conditions of which are controlled by the condition control unit, is supplied; and a temperature control unit that controls the temperature of the anion exchanger to be in the range of 20°C or higher and 100°C or lower. [5] A system for separating and capturing carbon dioxide, comprising: an anion exchanger packed tower packed with anion exchanger, to which a gas to be treated containing nitrogen oxides and / or sulfur oxides and carbon dioxide is supplied and which discharges a carbon dioxide-containing gas, a temperature control unit that controls the temperature of the anion exchanger to a range of 20°C to 100°C, and a carbon dioxide separation and capture unit that separates and captures carbon dioxide from the carbon dioxide-containing gas by one or more methods selected from the group consisting of an absorption method, an adsorption method, and a membrane separation method. [6] The carbon dioxide separation and capture system according to [5], further comprising a condition control unit that controls one or more conditions selected from the group consisting of a flow rate, a temperature, and humidity of the gas to be treated.[7] The carbon dioxide separation and capture system according to [5] or [6], wherein the carbon dioxide separation and capture unit is a unit that separates carbon dioxide at least by the absorption method and includes a carbon dioxide absorption unit that includes an amine compound solution and a first carbon dioxide desorption unit that includes a heating device, wherein the carbon dioxide absorption unit is a unit that brings the amine compound solution into contact with the carbon dioxide-containing gas to absorb carbon dioxide in the carbon dioxide-containing gas, and the first carbon dioxide desorption unit is a unit that desorbs carbon dioxide from the amine compound solution by heating the amine compound solution that has absorbed carbon dioxide with the heating device. [8] The carbon dioxide separation and capture system according to any one of [5] to [7], wherein the carbon dioxide separation and capture unit is a unit that separates carbon dioxide at least by the adsorption method and has a carbon dioxide adsorption unit including a solid adsorbent material having a carbon dioxide carrier supported on a porous support material, and a second carbon dioxide desorption unit including a heating device and / or a decompression device, wherein the carbon dioxide adsorption unit adsorbs carbon dioxide in the carbon dioxide-containing gas onto the solid adsorbent material by bringing the solid adsorbent material into contact with the carbon dioxide-containing gas, and the second carbon dioxide desorption unit desorbs carbon dioxide from the solid adsorbent material by heating the solid adsorbent material that has adsorbed carbon dioxide with the heating device and / or placing it under reduced pressure with the decompression device. [9] The carbon dioxide separation and capture system according to any one of [5] to [8], wherein the carbon dioxide separation and capture unit is a unit that separates and captures carbon dioxide at least by the membrane separation method and has a facilitated transport membrane into which a carbon dioxide carrier has been introduced.

[10] A method for separating and capturing carbon dioxide, comprising a separation and capture step of separating and capturing carbon dioxide from the gas to be treated using the carbon dioxide separation and capture system according to any one of [5] to [9].

[0009] According to the present disclosure, a method for easily removing nitrogen oxides and / or sulfur oxides can be provided.

[0010] 1 is a graph showing the change over time in the sulfur dioxide concentration of the carbon dioxide-containing gas discharged from the anion exchanger packed column in Example 1.

[0011] In the present disclosure, the term "X to Y" indicating a range means "X or more and Y or less." Furthermore, when a numerical range expressed as "X to Y" or "X or more and Y or less" is described in stages (for example, in order of preference), the upper and lower limits of each numerical range can be combined arbitrarily. Furthermore, in the present disclosure, a description such as "X such as x1, x2, and x3" lists x1, x2, and x3 as examples of X, and does not mean that X is limited to x1, x2, x3, etc. Below, embodiments of the present disclosure will be described in detail.

[0012] 1. Method for Removing Nitrogen Oxides and / or Sulfur Oxides A first embodiment of the present disclosure is a method for removing nitrogen oxides and / or sulfur oxides from a gas to be treated that contains nitrogen oxides and / or sulfur oxides and carbon dioxide, and includes a gas supplying step of supplying the gas to be treated to an anion exchanger-packed column packed with an anion exchanger.

[0013] According to the present embodiment, a method for removing nitrogen oxides and / or sulfur oxides from a gas to be treated, which contains nitrogen oxides and / or sulfur oxides and carbon dioxide, can be provided by a simple operation of supplying the gas to be treated containing nitrogen oxides and / or sulfur oxides to a column packed with an anion exchanger. This method is advantageous in terms of cost because a relatively inexpensive anion exchange resin can be used to remove nitrogen oxides and / or sulfur oxides, and it is also possible to reduce equipment costs because no large-scale equipment is required.

[0014] The anion exchanger packed column is a packed column packed with an anion exchanger.

[0015] The anion exchanger has an anion exchange group introduced into a substrate. The form of the anion exchanger is not particularly limited, and may be particulate, fibrous, spongy, membrane, or a composite structure thereof (for example, a structure in which a particulate substrate is composited onto the surface of a sponge substrate). Among these, the anion exchanger is preferably a particulate substrate, a sponge substrate, or a composite structure containing a particulate substrate and a sponge substrate, because it can increase the packing density and facilitates packing even in a large packed column.

[0016] The material constituting the substrate of the anion exchanger is not particularly limited, but due to their high strength and excellent chemical stability, preferred are olefin polymers such as polyethylene, polypropylene, polymethylpentene-1, and polycyclopentadiene; crosslinked polymers of the olefin polymers; styrene polymers such as polystyrene, polychlorostyrene, polychloromethylstyrene, and poly-α-methylstyrene; crosslinked polymers of the styrene polymers; (meth)acrylic polymers such as polymethyl methacrylate; crosslinked polymers of the (meth)acrylic polymers; unsaturated carboxylic acid ester polymers such as polydiethyl fumarate and polydiisopropyl fumarate; and crosslinked polymers of the unsaturated carboxylic acid ester polymers. The materials constituting the substrate may be used alone, or two or more may be used in any combination and ratio.

[0017] The surface structure of the substrate of the anion exchanger is not particularly limited, and may be a porous structure having macropores (MR type) or a gel type having no macropores.

[0018] The anion exchange group introduced into the anion exchanger may be a weakly basic anion exchange group, such as a tertiary amino group, or a strongly basic anion exchange group, such as a quaternary ammonium group, and two or more types may be introduced in combination. Specific examples of suitable anion exchange groups include weakly basic anion exchange groups such as a dimethylamino group, a diethylamino group, a dibutylamino group, and a polyethyleneimino group; and strongly basic anion exchange groups such as a trimethylammonium group, a triethylammonium group, a tributylammonium group, a (2-hydroxyethyl)dimethylammonium group, a (3-hydroxypropyl)dimethylammonium group, a di(2-hydroxyethyl)methylammonium group, and a dimethylsulfonium group. Among these ion exchange groups, weakly basic anion exchange groups are preferred because of their high heat resistance and ease of regeneration.

[0019] The amount of anion exchange groups introduced into the anion exchanger is not particularly limited, but is preferably 0.1 mg equivalent / g to 6.0 mg equivalent / g, more preferably 0.5 mg equivalent / g to 5.0 mg equivalent / g.

[0020] The counter ions of the anion exchange groups are not particularly limited, but are preferably hydroxide ions and / or bicarbonate ions. When the counter ions of the anion exchange groups are hydroxide ions, the counter ions are exchanged from hydroxide ions to bicarbonate ions when a gas to be treated containing carbon dioxide is supplied to the anion exchanger-packed column. When the counter ions of the anion exchange groups are bicarbonate ions or hydroxide ions, the bicarbonate ions or hydroxide ions exchange with nitrite ions derived from nitrogen dioxide, nitrate ions derived from nitrogen dioxide, sulfite ions derived from sulfur dioxide, and sulfate ions derived from sulfur dioxide in the gas to be treated. By capturing and immobilizing these ions, nitrogen oxides and / or sulfur oxides can be removed from the gas to be treated. On the other hand, carbon dioxide in the gas to be treated does not exchange with bicarbonate ions and is therefore not captured by the anion exchanger and passes directly through the anion exchanger-packed column. The distribution of the ion exchange groups in the substrate is also not particularly limited; they may be introduced in a concentrated manner on the surface of the substrate or uniformly into the substrate.

[0021] The method for introducing anion exchange groups into a substrate is not particularly limited, and examples thereof include a method of introducing anion exchange groups into a substrate by reacting chloromethyl groups present in the substrate with various amine compounds; a method of graft polymerizing a polymer chain having chloromethyl groups onto the substrate, and then reacting the chloromethyl groups with various amine compounds to introduce anion exchange groups into the substrate; a method of graft polymerizing a polymer chain onto the substrate, then introducing chloromethyl groups into the graft chain, and then reacting the chloromethyl groups with various amine compounds to introduce anion exchange groups into the substrate; a method of introducing anion exchange groups into a substrate by reacting epoxy groups present in the substrate with various amine compounds; a method of graft polymerizing a polymer chain having epoxy groups onto the substrate, and then reacting the epoxy groups with various amine compounds to introduce anion exchange groups into the substrate; and a method of graft polymerizing a polymer chain onto the substrate, then introducing epoxy groups into the graft chain, and then reacting the epoxy groups with various amine compounds to introduce anion exchange groups into the substrate.

[0022] The packed tower packed with the anion exchanger is not particularly limited as long as it can pass the gas to be treated, but is preferably a column. The shape of the packed tower is not particularly limited, but is preferably cylindrical or rectangular. The height of the layer of the anion exchanger packed inside the packed tower is preferably 1 cm to 500 cm, although this depends on the cross-sectional area of ​​the packed tower and the flow rate of the gas to be treated, etc.

[0023] The method according to this embodiment preferably includes a temperature control step of controlling the temperature of the anion exchanger packed in the anion exchanger-packed column within a specific range. In the temperature control step, the temperature of the anion exchanger is preferably controlled to 20°C to 100°C, more preferably 40°C to 80°C, and even more preferably 40°C to 60°C. By controlling the temperature of the anion exchanger at or above the lower limit, nitrogen oxides and / or sulfur oxides can be removed at a sufficient rate. By controlling the temperature of the anion exchanger at or below the upper limit, decomposition of the anion exchange groups introduced into the anion exchanger is suppressed, ensuring the stability of the anion exchange groups, thereby enabling a rapid ion exchange reaction. The method for controlling the temperature of the anion exchanger is not particularly limited, and examples thereof include placing the anion exchanger-packed column in a thermostatic bath.

[0024] The temperature of the gas to be treated containing nitrogen oxides and / or sulfur oxides and carbon dioxide, which is supplied to the anion exchanger packed column, is not particularly limited, but is preferably 20°C to 100°C, more preferably 40°C to 80°C, and even more preferably 40°C to 60°C. When the temperature of the gas to be treated is equal to or higher than the above lower limit, nitrogen oxides and / or sulfur oxides can be removed at a sufficient rate. When the temperature of the gas to be treated is equal to or lower than the above upper limit, decomposition of the anion exchange groups in the anion exchanger is suppressed, and the stability of the anion exchange groups can be ensured, thereby enabling a rapid ion exchange reaction.

[0025] The relative humidity of the gas to be treated is not particularly limited, but a wet state is preferable to a dry state, and the relative humidity is more preferably 50% to 95%, and even more preferably 70% to 90%. The moisture content of the anion exchanger is also not particularly limited, but is preferably 30% to 80%.

[0026] The flow rate of the gas to be treated supplied to the anion exchanger packed column is not particularly limited, but is preferably a flow rate such that the linear velocity and / or space velocity are within a specific range. Specifically, the linear velocity of the gas to be treated is preferably 0.01 m / sec to 1.00 m / sec, more preferably 0.10 m / sec to 0.50 m / sec, and even more preferably 0.13 m / sec to 0.50 m / sec. The space velocity of the gas to be treated is preferably 100 hr －１ ~10,000 hours －１ It is preferable that the temperature is 500 hours or more. －１ ~9,000 hours －１ More preferably, 1,000 hours －１ ~5,000 hours －１ More preferably, 2,400 hours －１ ~3,600 hours －１ It is even more preferred that:

[0027] In order to control any one or more of the flow rate, temperature, and humidity of the gas to be treated within the above-mentioned preferred ranges, this embodiment preferably performs a condition control step of controlling one or more conditions selected from the group consisting of the flow rate, temperature, and humidity of the gas to be treated prior to the gas supply step. The flow rate of the gas to be treated can be controlled by control means such as a mass flow controller and a flow control valve. The temperature of the gas to be treated can be controlled by control means such as a heater, a cooler, and a heat exchanger. Furthermore, the humidity can be controlled by a bubbler, a precision humidity generator, or the like.

[0028] The composition of the gas to be treated preferably includes 10 ppm to 300 ppm of nitrogen oxides, 1 ppm to 200 ppm of sulfur oxides, and 5% to 20% by volume of carbon dioxide. The composition of the carbon dioxide-containing gas discharged from the ion exchanger packed column preferably includes 20 ppm or less of nitrogen dioxide, 5 ppm or less of sulfur oxides, and 10% or more of the carbon dioxide concentration of the gas to be treated. It is more preferred that the nitrogen dioxide content of the nitrogen oxides is 5 ppm or less, 0 ppm of sulfur oxides, and a carbon dioxide concentration within ±1% by volume of the carbon dioxide concentration of the gas to be treated. It is even more preferred that the nitrogen dioxide content is 5 ppm or less, 0 ppm of sulfur oxides, and a carbon dioxide concentration equal to the carbon dioxide concentration of the gas to be treated. Nitrogen dioxide in nitrogen oxides is removed in the anion exchanger packed column by ionizing to nitrate ions, but nitric oxide has low solubility in water and does not ionize, so the removal efficiency in the anion exchanger packed column is not high, and the overall nitrogen oxide concentration does not necessarily reach 0 ppm. However, since nitric oxide has low solubility in water, it does not dissolve in the carbon dioxide separation membrane, and it is thought that its impact on the separation and recovery of carbon dioxide, which will be described later, is small.

[0029] The gas to be treated may contain components other than nitrogen oxides and / or sulfur oxides and carbon dioxide, such as nitrogen, oxygen, carbon monoxide, hydrogen, and hydrogen sulfide, as long as the effects of the present disclosure are not impaired.

[0030] According to the method of this embodiment, when a gas to be treated containing nitrogen oxides and / or sulfur oxides and carbon dioxide is supplied to an ion exchanger packed column under the above-described suitable conditions, it is possible to reduce the concentration of nitrogen oxides and / or sulfur oxides in the gas to be treated to 20 ppm or less, even if the nitrogen oxides and / or sulfur oxides are present in the gas to be treated at a high concentration of 100 ppm or more.

[0031] Nitrogen oxides include nitric oxide, nitrous oxide, and nitrogen dioxide. The gas to be treated may contain only one of these, or two or more of them in any combination and ratio. The method according to this embodiment is particularly suitable for removing nitrogen dioxide. Furthermore, sulfur oxides include sulfur dioxide and sulfur trioxide. The gas to be treated may contain only one of these, or both of them in any ratio.

[0032] The method for supplying the gas to be treated to the anion exchanger packed column is not particularly limited, and examples thereof include a method in which the gas to be treated is supplied so as to move from one end of the ion exchanger packed column to the other. The direction in which the gas to be treated moves depends on the arrangement of the packed column and is not particularly limited, and may be the direction of gravity, the direction opposite to the direction of gravity, a direction perpendicular to the direction of gravity, or a direction at any angle relative to these directions. Note that multiple anion exchanger packed columns may be arranged in series or parallel and connected for use.

[0033] 2. Nitrogen Oxide and / or Sulfur Oxide Removal System A second embodiment of the present disclosure is a system for removing nitrogen oxides and / or sulfur oxides from a gas to be treated containing nitrogen oxides and / or sulfur oxides and carbon dioxide, the system including an anion exchanger packed tower to which the gas to be treated is supplied. The anion exchanger packed tower is packed with an anion exchanger. The system according to this embodiment preferably includes a condition control unit that controls one or more conditions selected from the group consisting of the flow rate, temperature, and humidity of the gas to be treated, in order to more efficiently remove nitrogen oxides and / or sulfur oxides from the gas to be treated. The system according to this embodiment preferably also includes a temperature control unit that controls the temperature of the anion exchanger within a specific range, in order to more stably and quickly remove nitrogen oxides and / or sulfur oxides from the gas to be treated.

[0034] The system according to this embodiment is a system for performing the removal method according to the first embodiment. That is, the ion exchanger packed column, the condition control unit, and the temperature adjustment unit according to this embodiment perform the gas supply step, the condition control step, and the temperature adjustment step according to the first embodiment, respectively. Therefore, with regard to each element of the system according to this embodiment, the explanation given in the section <1. Method for Removing Nitrogen Oxides and / or Sulfur Oxides> is incorporated herein by reference.

[0035] 3. Carbon Dioxide Separation and Capture System A third embodiment of the present disclosure is a system for separating and capturing carbon dioxide, comprising: an anion exchanger packed tower that receives a gas to be treated containing nitrogen oxides and / or sulfur oxides and carbon dioxide and discharges the carbon dioxide-containing gas; and a carbon dioxide separation and capture unit that separates and captures carbon dioxide from the carbon dioxide-containing gas by one or more methods selected from the group consisting of absorption, adsorption, and membrane separation. The anion exchanger packed tower is packed with an anion exchanger. The system according to this embodiment preferably includes a condition control unit that controls one or more conditions selected from the group consisting of the flow rate, temperature, and humidity of the gas to be treated to more efficiently remove nitrogen oxides and / or sulfur oxides from the gas to be treated. The system according to this embodiment preferably also includes a temperature control unit that controls the temperature of the anion exchanger within a specific range to more stably and quickly remove nitrogen oxides and / or sulfur oxides from the gas to be treated.

[0036] In the system according to the present embodiment, the gas from which nitrogen oxides and / or sulfur oxides have been sufficiently removed by the system according to the second embodiment is subjected to carbon dioxide separation and recovery by one or more methods selected from absorption, adsorption, and membrane separation. That is, the carbon dioxide-containing gas used in one or more methods selected from absorption, adsorption, and membrane separation is the gas from which nitrogen oxides and / or sulfur oxides have been removed. Therefore, even when an amine compound is used in the absorption, adsorption, or membrane separation, the system according to the present embodiment can prevent the amine compound from being consumed in the reaction between the nitrogen oxides and / or sulfur oxides and the amine compound, or the salt of the amine compound produced by the reaction between the nitrogen oxides and / or sulfur oxides and the amine compound from inhibiting the reaction between the amine compound and carbon dioxide. As a result, the system according to the present embodiment can efficiently separate and recover carbon dioxide. Furthermore, in a preferred embodiment of the present embodiment, carbon dioxide can be separated and recovered stably for a long period of time.

[0037] In addition, since the present embodiment does not require large-scale facilities, it is possible to construct an inexpensive and compact system. That is, by using the system according to the present embodiment, it becomes possible to separate and capture carbon dioxide at low cost from carbon dioxide-containing exhaust gas generated not only by relatively small-scale carbon dioxide generating sources but also by large-scale carbon dioxide generating sources such as thermal power plants, steelworks blast furnaces, and cement factories. Therefore, the system according to the present embodiment can greatly contribute to reducing carbon dioxide.

[0038] The ion exchanger packed column, condition control unit, and temperature control unit in this embodiment are synonymous with the ion exchanger packed column, condition control unit, and temperature control unit in the second embodiment, and preferred aspects thereof are also the same. The ion exchanger packed column, condition control unit, and temperature control unit in this embodiment perform the gas supply step, condition control step, and temperature control step in the first embodiment, respectively. Therefore, the explanations given in the sections <1. Method for Removing Nitrogen Oxides and / or Sulfur Oxides> and <2. System for Removing Nitrogen Oxides> are incorporated herein by reference for these elements of the system according to this embodiment.

[0039] The absorption method, which is one of the methods for separating and capturing carbon dioxide in the carbon dioxide separation and capture section, is a method in which an amine compound solution is brought into contact with a carbon dioxide-containing gas to absorb carbon dioxide in the carbon dioxide-containing gas, and then the amine compound solution that has absorbed the carbon dioxide is heated to desorb carbon dioxide from the amine compound solution.

[0040] Therefore, when the carbon dioxide separation and capture unit is a part that separates carbon dioxide by at least an absorption method, the carbon dioxide separation and capture unit has a carbon dioxide absorption unit that includes an amine compound solution and a first carbon dioxide desorption unit that includes a heating device.

[0041] The carbon dioxide absorption unit is a unit that brings the amine compound solution into contact with the carbon dioxide-containing gas, thereby absorbing carbon dioxide in the carbon dioxide-containing gas into the amine compound solution. The method for bringing the amine compound solution into contact with the carbon dioxide-containing gas is not particularly limited, but a preferred example is a method in which the carbon dioxide-containing gas is bubbled (blowed) into the amine compound solution. Therefore, the carbon dioxide absorption unit is preferably equipped with bubbling means such as a bubbling tube and a bubbler.

[0042] The temperature at which the amine compound solution is brought into contact with the carbon dioxide-containing gas and carbon dioxide is absorbed into the amine compound solution is not particularly limited, but is preferably 10°C to 60°C.

[0043] The first carbon dioxide desorption section is a section in which the amine compound solution that has absorbed carbon dioxide is heated by a heating device to desorb carbon dioxide from the amine compound solution. The heating device is not particularly limited as long as it can heat the amine compound solution, and any heating device such as a known heater or a device equivalent thereto can be appropriately adopted. The temperature at which carbon dioxide absorbed in the amine compound solution is desorbed is generally 100°C or higher when the solvent is water, but this temperature can be lowered to 90°C or lower by changing the solvent to an organic solvent or using a sweep gas.

[0044] Examples of the solvent for the amine compound solution include water; alcohols such as 4-methoxyphenol, tetrafluoropropanol, and pentafluoropropanol; ethers such as diethylene glycol diethyl ether; ionic liquids; and mixed solvents thereof.

[0045] The amine compound contained in the amine compound solution is an organic compound having one or more amino groups selected from the group consisting of a primary amino group, a secondary amino group, and a tertiary amino group, and is preferably an organic low-molecular-weight compound having the amino group. Specific preferred examples of the amine compound include alkanolamines such as monoethanolamine, diethanolamine, triethanolamine, methyldiethanolamine, diisopropanolamine, and diglycolamine; N,N-dimethyl-1,4-diaminobutane, N,N-dimethyl-1,3-diaminopropane, N,N-dimethyl-1,2-diaminopropane, N,N-dimethyl-1,2-diaminoethane, N,N-diethyl-1,4-diaminobutane, N,N-diethyl-1,3-diaminopropane, N,N-diethyl-1,2-diaminopropane, N,N-diethyl-1,2-diaminoethane, N,N-dipropyl-1,4-diaminobutane, N,N-dipropyl-1,3-diaminopropane, N,N-dipropyl ... alkanediamines such as diaminopropane and N,N-dipropyl-1,2-diaminoethane; polyalkylenepolyamines such as diethylenetriamine; piperazine compounds such as piperazine, N-methylpiperazine, N-ethylpiperazine, N-(2-hydroxyethyl)piperazine, N-(2-hydroxypropyl)piperazine, N-(3-aminopropyl)piperazine, N-(2-aminoethyl)piperazine, N-(3,6-diazahexyl)-N'-(3-azapropyl)piperazine, and N-(3,6,9-triazanonyl)piperazine; polyethylenepolyamines such as triethylenetetramine, tetraethylenepentamine, N,N-bis(2-aminoethyl)diethylenetriamine, pentaethylenehexamine, and hexaethyleneheptamine;Piperidine, 2-methylpiperidine, 1-(2,3-dihydroxypropyl)-piperidine, 1-(2,3-dihydroxypropyl)-4-methylpiperidine, 1-(2,3-dihydroxypropyl)-4-ethylpiperidine, 1-(2,3-dihydroxypropyl)-4-propylpiperidine, 1-(2,3-dihydroxypropyl)-4-butylpiperidine, 1-(2-hydroxy-3-methoxypropyl)-piperidine, 1-(2-hydroxy-3-methoxypropyl)-4-methylpiperidine, 1-(2-hydroxy-3-methoxypropyl)-4-ethylpiperidine, 1-(2-hydroxypropyl)-4-methylpiperidine, 1-(2-hydroxy-3-methoxypropyl)-4-ethylpiperidine, 1-(2-hydroxypropyl)-4-methylpiperidine, Examples of the amine compounds include piperidine compounds such as 1-(2-hydroxy-3-methoxypropyl)-4-propylpiperidine, 1-(2-hydroxy-3-methoxypropyl)-4-butylpiperidine, 1-(2,3-dimethoxypropyl)-piperidine, 1-(2,3-dimethoxypropyl)-4-methylpiperidine, 1-(2,3-dimethoxypropyl)-4-ethylpiperidine, 1-(2,3-dimethoxypropyl)-4-propylpiperidine, and 1-(2,3-dimethoxypropyl)-4-butylpiperidine; and bridged bicyclic amines such as 1,4-diazabicyclo[2.2.2]octane-2-methanol. The amine compounds may be used alone or in any combination and ratio of two or more.

[0046] In the present disclosure, the term "low molecular weight" refers to a compound that does not have a molecular weight distribution and has a molecular weight of 2,000 or less, preferably 1,000 or less, more preferably 800 or less, and even more preferably 500 or less, and is distinguished from a "polymer" or "resin" that has a molecular weight distribution and has a molecular weight of 1,000 or more.

[0047] The content of the amine compound in the amine compound solution is not particularly limited, but is preferably 5% by mass to 70% by mass based on the total amount of the amine compound and the solvent.

[0048] The adsorption method, which is one method for separating carbon dioxide in the carbon dioxide separation and capture section, is a carbon dioxide separation and capture method using a solid adsorbent, and specific examples include a method in which carbon dioxide is adsorbed onto a metal-organic framework (MOF), which is a carbon dioxide adsorbent, and the carbon dioxide adsorbed onto the MOF is desorbed under heating conditions and / or reduced pressure conditions; and a method in which carbon dioxide is adsorbed onto a solid adsorbent in which a carbon dioxide carrier is supported on a porous support material such as silica, and the carbon dioxide adsorbed onto the solid adsorbent is desorbed under heating conditions and / or reduced pressure conditions. In this embodiment, the adsorption method is preferably performed using a solid adsorbent in which a carbon dioxide carrier is supported on a porous support material.

[0049] Therefore, when the carbon dioxide separation and capture unit is a part that separates and captures carbon dioxide at least by an adsorption method, the carbon dioxide separation and capture unit has a carbon dioxide adsorption unit that includes a solid adsorbent material in which a carbon dioxide carrier is supported on a porous support material, and a second carbon dioxide desorption unit that includes a heating device and / or a pressure reduction device.

[0050] The carbon dioxide adsorption section is a section that adsorbs carbon dioxide in a carbon dioxide-containing gas onto a solid adsorbent by contacting the solid adsorbent with the carbon dioxide-containing gas. The method for contacting the solid adsorbent with the carbon dioxide-containing gas is not particularly limited, but a preferred example is a method in which the carbon dioxide-containing gas is supplied to a solid adsorbent packed tower packed with the solid adsorbent. The packed tower packed with the solid adsorbent is not particularly limited as long as it can circulate the carbon dioxide-containing gas, but is preferably a tubular body such as a column or a U-shaped tube. The shape of the packed tower is not particularly limited, but is preferably cylindrical or rectangular. In addition, the bed height of the solid adsorbent packed inside the packed tower is preferably 5 cm to 500 cm, depending on the cross-sectional area of ​​the packed tower and the flow rate of the carbon dioxide-containing gas.

[0051] The temperature at which the solid adsorbent is brought into contact with the carbon dioxide-containing gas and carbon dioxide is adsorbed onto the solid adsorbent is not particularly limited as long as it is a temperature that the solid adsorbent can withstand, and is preferably 20°C to 60°C.

[0052] The second carbon dioxide desorption section is a section in which carbon dioxide is desorbed from the solid adsorbent by heating the solid adsorbent that has adsorbed carbon dioxide using a heating device and / or placing it under reduced pressure using a pressure-reducing device. The heating device is not particularly limited as long as it can heat the amine compound solution, and any heating device such as a known heater or a device equivalent thereto can be appropriately adopted. The pressure-reducing device is also not particularly limited, and any pressure-reducing device such as a known vacuum pump or a device equivalent thereto can be appropriately adopted. In the second carbon dioxide desorption section, carbon dioxide is preferably desorbed by heating the solid adsorbent to 60°C to 200°C and / or placing the solid adsorbent under reduced pressure of 0.2 Pa or less.

[0053] Porous support materials used in solid adsorbents include mesoporous silica, polymethyl methacrylate, alumina, silica-alumina, clay minerals, magnesia, zirconia, zeolite, zeolite-related compounds, activated carbon, and carbon molecular sieves. The porous support materials may be used alone or in any combination and ratio of two or more.

[0054] The porous support material is preferably a material with a large specific surface area and pore volume in order to support a large amount of carbon dioxide carrier. More specifically, the specific surface area of ​​the porous support material is preferably 50 m ２ / g to 1,000m ２ / g, more preferably 400m ２ / g to 1,000m ２ The pore volume of the porous support material is preferably 0.1 cm ３ / g ~ 2.3 cm ３ / g, more preferably 1.5 cm ３ / g ~ 2.3 cm ３ / g.

[0055] Examples of carbon dioxide carriers supported on the porous support material include alkanolamines, polyvalent amines, and alkali metal carbonates. Alkanolamines and polyvalent amines are preferably amines having a bulky group bonded to a nitrogen atom, as they can desorb carbon dioxide at lower temperatures. Specific examples of suitable alkanolamines include 2-(isopropylamino)ethanol and diisopropanolamine. Specific examples of suitable polyvalent amines include polyethyleneimine, 4-butanediamine, N,N,N',N'-tetrakis(3-(isopropylamino)propyl)-1,4-butanediamine, 1,14-bis(isopropylamino)-3,6,9,12-tetraazatetradecane, 1,17-bis(isopropylamino)-3,6,9,12,15-pentaazaheptadecane, and 1,8-bis(isopropylamino)-3,6-diazaoctane. Specific examples of suitable alkali metal carbonates include lithium carbonate, sodium carbonate, potassium carbonate, rubidium carbonate, cesium carbonate, and mixtures thereof. The carbon dioxide carrier may be used alone or in any combination and ratio of two or more.

[0056] The method for supporting the carbon dioxide carrier on the porous support material is not particularly limited, and for example, a supporting method can be adopted in which the carbon dioxide carrier is dissolved or dispersed in a solvent such as water or alcohol, mixed with the porous support material, and then the solvent is removed.

[0057] Membrane separation, which is one of the methods for separating carbon dioxide in the carbon dioxide separation and capture section, is a method for separating and capturing carbon dioxide using a membrane. Since membrane separation uses a concentration difference as the driving force to separate carbon dioxide, it is not necessary to input energy for moving the medium and regenerating the membrane, and capture costs can be reduced. In this embodiment, among membrane separation methods, membrane separation methods using organic polymer membranes that can be easily chemically modified and modularized are preferred, and membrane separation methods using facilitated transport membranes that can improve carbon dioxide permeation flux and carbon dioxide selectivity are more preferred. Organic polymer membranes are also advantageous in that they can be mass-produced and cost-reduced.

[0058] Therefore, when the carbon dioxide separation and capture unit is a part that separates and captures carbon dioxide by at least a membrane separation method, the carbon dioxide separation and capture unit preferably has a facilitated transport membrane into which a carbon dioxide carrier is introduced.

[0059] Examples of carbon dioxide carriers include alkali metal carbonates, alkali metal bicarbonates, alkali metal hydroxides, amine compounds, and mixtures thereof. Among these, amine compounds are preferred as carbon dioxide carriers because they react reversibly or reversibly and selectively with carbon dioxide. One carbon dioxide carrier may be used alone, or two or more carbon dioxide carriers may be used in any combination and ratio.

[0060] Specific preferred examples of alkali metal carbonates include lithium carbonate, sodium carbonate, potassium carbonate, rubidium carbonate, cesium carbonate, and mixtures thereof. Specific preferred examples of alkali metal bicarbonates include lithium bicarbonate, sodium bicarbonate, potassium bicarbonate, rubidium bicarbonate, cesium bicarbonate, and mixtures thereof. Specific preferred examples of alkali metal hydroxides include lithium hydroxide, sodium hydroxide, potassium hydroxide, rubidium hydroxide, and mixtures thereof.

[0061] Specific preferred examples of the amine compound include alkanolamines such as N-(2-aminoethyl)ethanolamine, N-[2-(dimethylamino)ethyl]-N-methylethanolamine, and N-[2-(diethylamino)ethyl]ethanolamine; N-(1,2-dihydroxy-n-propyl)piperazine, N-[(1-hydroxymethyl,2-hydroxy)-n-propyl]piperazine, N-[(1-hydroxy-2-hydroxymethyl)-n-propyl]piperazine, and N-(1,2-dihydroxy-n-propyl)-N'-methyl-piperazine. triethylenetetramines such as N-[1,2-bis(hydroxymethyl)-n-propyl]piperazine, N-[1,2-bis(hydroxymethyl)-n-propyl]-N'-methyl-piperazine, diethylenetriamine, 1,4,7,10-tetraazadecane, N,N-bis(2-aminoethyl)-1,2-ethanediamine, 1-[2-[(2-aminoethyl)amino]ethyl]-piperazine, and 1,4-bis(2-aminoethyl)-piperazine; 1,4,7,10,13-pentaazatridecane, N,N,N'-tris(2-azaethyl)- tetraethylenepentamine such as N,N,N',N'-tetrakis(2-aminoethyl)-1,2-ethanediamine, 1-[2-[2-[2-[(2-aminoethyl)amino]ethyl]amino]ethyl]-piperazine, 1-[2-[bis(2-aminoethyl)amino]ethyl]-piperazine, and bis[2-(1-piperazinyl)ethyl]amine; 1,4,7,10,13,16-hexaazahexadecane, N,N,N',N'-tetrakis(2-aminoethyl)-1,2-ethanediamine, N,N-bis(2-aminoethyl)-N'-[2-[(2-aminoethyl)amino]ethyl pentaethylenehexamines such as 1-[2-[2-[2-[2-[2-[(2-aminoethyl)amino]ethyl]amino]ethyl]amino]ethyl]-piperazine, 1-[2-[2-[2-[bis(2-aminoethyl)amino]ethyl]amino]ethyl]-piperazine, and N,N'-bis[2-(1-piperazinyl)ethyl]-1,2-ethanediamine; amino acids such as glycine, alanine, serine, proline, hydroxyproline, arginine, dimethylaminoglycine, and 2,3-diaminopropionic acid;and amine resins such as polyethyleneimine, polyamidoamine dendrimers, polyallylamine, poly-N-1,2-dimethylpropylallylamine, poly-N-methylallylamine, poly-N,N-dimethylallylamine, poly-2-vinylpiperidine, poly-4-vinylpiperidine, and polyvinylamine. In the present disclosure, "amine resin" refers to a polymer of a compound having one or more amino groups selected from the group consisting of a primary amino group, a secondary amino group, and a tertiary amino group, and having two or more of the amino groups.

[0062] The facilitated transport membrane (hereinafter also referred to as "carbon dioxide separation membrane") is not particularly limited as long as it is a membrane into which a carbon dioxide carrier is introduced, but it is preferable that it is a membrane having a laminated structure consisting of a porous membrane as a support layer and a separation functional layer containing a carbon dioxide carrier formed on the surface of the porous membrane.

[0063] The porous membrane is preferably an ultrafiltration membrane, and the molecular weight cutoff of the ultrafiltration membrane is preferably 500,000 or less, and more preferably 5,000 to 500,000.

[0064] Porous membrane materials that can be used include polyolefins such as polyethylene and polypropylene; fluorine-containing polymers such as polytetrafluoroethylene, polyvinyl fluoride, and polyvinylidene fluoride; chlorine-containing polymers such as polyvinyl chloride and polyvinylidene chloride; vinyl polymers such as polystyrene, polyacrylonitrile, and polymethyl methacrylate; condensation polymers such as polysulfone, polyethersulfone, polyetherimide, polyamide, polyurethane, and polyimide; and polysaccharides such as cellulose acetate and chitosan. The porous membrane materials may be used alone or in any combination and ratio of two or more.

[0065] The shape of the porous membrane may be a flat sheet membrane or a hollow fiber membrane, with the hollow fiber membrane being preferred.

[0066] The matrix polymer of the separation functional layer containing the carbon dioxide carrier is preferably a polar polymer with excellent affinity for the carbon dioxide carrier. Specific examples of suitable polar polymers include polyvinyl alcohol, polyethylene glycol, polyethylene glycol di(meth)acrylate, polypropylene glycol, polypropylene glycol di(meth)acrylate, polyethyleneimine, polyallylamine, polyamide epichlorohydrin, polyacrylic acid, polymethacrylic acid, polyvinylpyrrolidone, polyacrylamide, polyvinylamine, polyornithine, polylysine, copolymers thereof, and crosslinked products thereof. The matrix polymer may be used alone, or two or more may be used in any combination and ratio.

[0067] Specific preferred examples of carbon dioxide separation membranes include a polymer membrane in which a gel layer composed of a polyvinyl alcohol-polyacrylic acid copolymer gel membrane and 2,3-diaminopropionic acid is supported on a hydrophilic ultrafiltration membrane; a polymer membrane containing a water-soluble polymer such as polyvinyl alcohol and a specific amine compound (for example, N-(2-aminoethyl)ethanolamine); and a polymer membrane in which a polyamidoamine dendrimer having a high affinity for carbon dioxide is fixed inside a polymer obtained by photopolymerizing polyethylene glycol dimethacrylate.

[0068] The carbon dioxide separation membrane used in this embodiment is usually used as a carbon dioxide separation membrane module in which the carbon dioxide separation membrane is housed in a housing. Therefore, when carbon dioxide separation and capture is performed by membrane separation in the carbon dioxide separation and capture unit, the carbon dioxide separation and capture unit usually has a carbon dioxide separation membrane module (facilitated transport membrane module).

[0069] When the carbon dioxide separation membrane is a flat membrane, specific examples of the carbon dioxide separation membrane module include a laminated module in which membranes are laminated as they are or a laminated module in which membrane elements are fabricated and laminated; a pleated module in which a flat membrane is folded and housed in a cylindrical container; and a spiral module in which flat membranes are sandwiched between permeate side spacers (nets) and bonded in an envelope shape, and then wound around an axis serving as the permeation flow path via a feed side spacer; etc. On the other hand, when the carbon dioxide separation membrane is a tube, pipe, or hollow fiber membrane, specific examples of the carbon dioxide separation membrane module include a tubular module in which these are bundled together and a hollow fiber membrane module. Furthermore, when the carbon dioxide separation membrane is a monolithic type, a specific example of the carbon dioxide separation membrane module includes a tubular module in which monolithic elements are bundled together.

[0070] 4. Carbon Dioxide Separation and Capture Method A fourth embodiment of the present disclosure is a carbon dioxide separation and capture method, which includes a separation and capture step of separating and capturing carbon dioxide from a gas to be treated containing nitrogen oxides and / or sulfur oxides and carbon dioxide by the system according to the third embodiment. Alternatively, the carbon dioxide separation and capture method according to the fourth embodiment of the present disclosure is a method of separating and capturing carbon dioxide from a gas to be treated containing nitrogen oxides and / or sulfur oxides and carbon dioxide by the same mechanism as the system according to the third embodiment, and specific aspects thereof are as described in the third embodiment.

[0071] In other words, the carbon dioxide separation and recovery method according to this embodiment includes a gas supply step of supplying a gas to be treated containing nitrogen oxides and / or sulfur oxides and carbon dioxide to an anion exchanger packed column packed with an anion exchanger, and a carbon dioxide separation and recovery step of separating and recovering carbon dioxide from the carbon dioxide-containing gas discharged from the anion exchanger packed column by one or more methods selected from the group consisting of an absorption method, an adsorption method, and a membrane separation method. The method according to this embodiment further includes a condition control step of controlling one or more conditions selected from the group consisting of the flow rate, temperature, and humidity of the gas to be treated before the gas supply step, in order to more efficiently remove nitrogen oxides and / or sulfur oxides from the gas to be treated.

[0072] When an absorption method is adopted in the carbon dioxide separation and capture step, the carbon dioxide separation and capture step preferably includes an absorption step of bringing an amine compound solution into contact with the carbon dioxide-containing gas to absorb carbon dioxide in the carbon dioxide-containing gas, and a desorption step of heating the amine compound solution that has absorbed carbon dioxide to desorb carbon dioxide from the amine compound solution.

[0073] When an adsorption method is adopted in the carbon dioxide separation and capture step, the carbon dioxide separation and capture step preferably includes an adsorption step of adsorbing carbon dioxide in the carbon dioxide-containing gas onto a solid adsorbent material by bringing the carbon dioxide-containing gas into contact with the solid adsorbent material, the solid adsorbent material having a carbon dioxide carrier supported on a porous support material, and a desorption step of desorbing carbon dioxide from the solid adsorbent material by heating the solid adsorbent material that has adsorbed carbon dioxide or placing it under reduced pressure conditions.

[0074] When an adsorption method is adopted in the carbon dioxide separation and capture process, the carbon dioxide separation and capture process preferably includes a membrane separation process in which the carbon dioxide-containing gas is brought into contact with one end of a facilitated transport membrane into which a carbon dioxide carrier has been introduced, and the carbon dioxide in the carbon dioxide-containing gas is allowed to permeate to the other end of the facilitated transport membrane.

[0075] The gas supply step and the condition control step are respectively synonymous with the gas supply step and the condition control step in the first embodiment, and the preferred aspects thereof are also the same. Regarding these elements in this step, the explanation given in the section <1. Method for removing nitrogen oxides and / or sulfur oxides> is incorporated herein by reference. Regarding the method for separating and capturing carbon dioxide from a carbon dioxide-containing gas by one or more methods selected from the group consisting of an absorption method, an adsorption method, and a membrane separation method in the carbon dioxide separation and capture step, the explanation given in the section <3. Carbon dioxide separation and capture system> is incorporated herein by reference.

[0076] In the method according to this embodiment, even when an amine compound is used in the absorption method, the adsorption method, or the membrane separation method, it is possible to prevent the consumption of the amine compound due to the reaction between nitrogen oxides and / or sulfur oxides and the amine compound, and to prevent a salt of the amine compound produced by the reaction between nitrogen oxides and / or sulfur oxides and the amine compound from inhibiting the reaction between the amine compound and carbon dioxide. As a result, the system according to this embodiment can efficiently separate and capture carbon dioxide. Furthermore, in a preferred aspect of this embodiment, carbon dioxide can be separated and captured stably for a long period of time.

[0077] The present disclosure will be described in more detail below based on examples, but the present disclosure is not limited to these examples.

[0078] <Removal of sulfur dioxide using an anion exchanger packed column> (Example 1) After ion-exchanging the counter ions of a weakly basic anion exchange resin "Amberlite IRA96SB" (manufactured by DuPont, functional group: dimethylamino group) with bicarbonate ions, 15 mL of the resin was collected in a water-wet state and packed into a glass column with an inner diameter of 10 mm and a length of 300 mm, thereby preparing an anion exchanger packed column. This anion exchanger packed column was then placed in a thermostatic bath at 40°C.

[0079] A carbon dioxide / nitrogen mixed gas (carbon dioxide / nitrogen = 15 / 85 (v / v)) containing 100 ppm of sulfur dioxide was adjusted to a relative humidity of 90% using a high dew point generator (manufactured by Shin-ei Technology Co., Ltd.), and then supplied to an anion exchanger packed column at a flow rate of 0.7 L / min. The carbon dioxide-containing gas discharged from the anion exchanger packed column was analyzed with a gas analyzer (PG-350, manufactured by Horiba, Ltd.). The linear velocity of the gas to be treated supplied to the anion exchanger packed column was 0.13 m / s, and the space velocity was 2,400 h －１ It was.

[0080] The change in sulfur dioxide concentration of the carbon dioxide-containing gas over time is shown in Figure 1. As shown in Figure 1, the sulfur dioxide concentration was 0 ppm up to 4,000 minutes. This confirmed that sulfur dioxide could be removed from a carbon dioxide / nitrogen mixed gas containing sulfur dioxide by passing the gas through an anion exchanger packed column. The carbon dioxide concentration of the carbon dioxide-containing gas discharged from the anion exchanger packed column was 15% by volume, and it was also confirmed that carbon dioxide was not removed by the anion exchanger packed column.

[0081] Example 2 Sulfur dioxide was removed in the same manner as in Example 1, except that the anion exchanger was changed to an OH-type strongly basic anion exchange resin "Dowex Monosphere 550A" (manufactured by DuPont, counter ion was hydroxide ion).

[0082] When the change in sulfur dioxide concentration was analyzed over time, the sulfur dioxide concentration was 0 ppm up to 2,000 minutes. This confirmed that sulfur dioxide could be removed from a carbon dioxide / nitrogen mixed gas containing sulfur dioxide by passing the gas through an anion exchanger packed column. The carbon dioxide concentration of the carbon dioxide-containing gas discharged from the anion exchanger packed column was 15% by volume, confirming that carbon dioxide was not removed by the anion exchanger packed column.

[0083] Example 3 Sulfur dioxide was removed in the same manner as in Example 1, except that the anion exchanger packed column was placed in a thermostatic bath at 60°C.

[0084] When the change in sulfur dioxide concentration was analyzed over time, the sulfur dioxide concentration was 0 ppm up to 3,800 minutes. This confirmed that sulfur dioxide could be removed from a carbon dioxide / nitrogen mixed gas containing sulfur dioxide by passing the gas through an anion exchanger packed column. The carbon dioxide concentration of the carbon dioxide-containing gas discharged from the anion exchanger packed column was 15% by volume, confirming that carbon dioxide was not removed by the anion exchanger packed column.

[0085] Example 4 Sulfur dioxide was removed in the same manner as in Example 1, except that the anion exchanger packed column was placed in a thermostatic bath at 80°C.

[0086] When the change in sulfur dioxide concentration was analyzed over time, the sulfur dioxide concentration was 0 ppm up to 1,800 minutes. This confirmed that sulfur dioxide could be removed from a carbon dioxide / nitrogen mixed gas containing sulfur dioxide by passing the gas through an anion exchanger packed column. The carbon dioxide concentration of the carbon dioxide-containing gas discharged from the anion exchanger packed column was 15% by volume, confirming that carbon dioxide was not removed by the anion exchanger packed column.

[0087] Example 5: After the counter ions of the weakly basic anion exchange resin "Amberlite IRA 96SB" (manufactured by DuPont, functional group: dimethylamino group) were exchanged with bicarbonate ions, 10 mL of the resin was collected in a water-wet state and packed into a glass column with an inner diameter of 8 mm and a length of 300 mm. Sulfur dioxide was removed in the same manner as in Example 1. The linear velocity of the gas to be treated supplied to the anion exchanger-packed column was 0.20 m / s, and the space velocity was 3,600 h －１ It was.

[0088] When the change in sulfur dioxide concentration was analyzed over time, the sulfur dioxide concentration was 0 ppm up to 3,000 minutes. This confirmed that sulfur dioxide could be removed from a carbon dioxide / nitrogen mixed gas containing sulfur dioxide by passing the gas through an anion exchanger packed column. The carbon dioxide concentration of the carbon dioxide-containing gas discharged from the anion exchanger packed column was 15% by volume, confirming that carbon dioxide was not removed by the anion exchanger packed column.

[0089] Example 6: After the counter ions of the weakly basic anion exchange resin "Amberlite IRA 96SB" (manufactured by DuPont, functional group: dimethylamino group) were exchanged with bicarbonate ions, 4 mL of the resin was collected in a water-wet state and packed into a glass column with an inner diameter of 5 mm and a length of 300 mm. Sulfur dioxide was removed in the same manner as in Example 1. The linear velocity of the gas to be treated supplied to the anion exchanger-packed column was 0.50 m / s, and the space velocity was 9,000 h －１ It was.

[0090] When the change in sulfur dioxide concentration was analyzed over time, the sulfur dioxide concentration was 0 ppm up to 1,400 minutes. This confirmed that sulfur dioxide could be removed from a carbon dioxide / nitrogen mixed gas containing sulfur dioxide by passing the gas through an anion exchanger packed column. The carbon dioxide concentration of the carbon dioxide-containing gas discharged from the anion exchanger packed column was 15% by volume, confirming that carbon dioxide was not removed by the anion exchanger packed column.

[0091] Nitrogen dioxide removal using an anion exchanger packed column Example 7 Nitrogen gas containing 100 ppm of nitrogen dioxide was mixed with carbon dioxide gas to prepare a carbon dioxide / nitrogen mixed gas containing 85 ppm of nitrogen dioxide (carbon dioxide / nitrogen = 15 / 85 (v / v)). Nitrogen dioxide removal was carried out in the same manner as in Example 1, except that the gas to be treated was changed to the mixed gas prepared above.

[0092] When the change in nitrogen dioxide concentration was analyzed over time, the nitrogen dioxide concentration was 20 ppm or less up to 10,000 minutes. This shows that by passing the gas through an anion exchanger packed column, nitrogen dioxide could be reduced from the carbon dioxide / nitrogen mixed gas containing nitrogen dioxide. In addition, the carbon dioxide concentration of the carbon dioxide-containing gas discharged from the anion exchanger packed column was 15%, and it was also confirmed that carbon dioxide was not removed by the anion exchanger packed column.

[0093] Carbon Dioxide Separation and Capture System Combining an Anion Exchanger Packed Column and Absorption Method Example 8 A carbon dioxide / nitrogen mixed gas (carbon dioxide / nitrogen = 15 / 85 (v / v)) containing 100 ppm of sulfur dioxide was adjusted to a relative humidity of 90%. The same anion exchanger packed column as in Example 1 was placed in a thermostatic bath at 40°C, and the adjusted mixed gas was supplied to the anion exchanger packed column at a flow rate of 1 L / min. The carbon dioxide-containing gas discharged from the anion exchanger packed column was then blown into an amine compound solution at 40°C prepared by mixing 30 g of monoethanolamine and 70 g of pure water for 1 hour. The temperature of the amine compound solution was then raised to 110°C, and 100% nitrogen gas was passed through the amine compound solution at a flow rate of 1 L / min for 1 hour, thereby desorbing carbon dioxide from the amine compound solution. The amount of carbon dioxide recovered was 5.0 L. The carbon dioxide absorption / desorption cycle was repeated 50 times. Since the amount of carbon dioxide recovered in the 50th cycle was 5.0 L, it was confirmed that this method can maintain the same amount of carbon dioxide recovered as in the first cycle, even if carbon dioxide absorption and desorption are repeated.

[0094] Comparative Example 1 Without using an anion exchanger packed column, a mixed gas conditioned to the same relative humidity as in Example 8 was blown into the amine compound solution used in Example 8. When the carbon dioxide absorption / desorption cycle was repeated 50 times in the same manner as in Example 8, it was confirmed that the amount of carbon dioxide recovered decreased to 4.1 L at the 50th cycle.

[0095] <Carbon dioxide separation and capture system combining anion exchanger packed column and adsorption method> (Example 9) 6.7 g of 2-(isopropylamino)ethanol (manufactured by Fujifilm Wako Pure Chemical Industries, Ltd.) was dissolved in 20 g of methanol, and 10 g of mesoporous silica (MSU-F, manufactured by Aldrich Co., Ltd.) was added and uniformly dispersed, and the mixture was stirred under reduced pressure to remove the methanol, thereby producing a solid adsorbent.

[0096] 10 g of the solid adsorbent was packed into a glass U-shaped tube (inner diameter 15 mm, height 150 mm), and both ends were fixed with glass wool. Next, the U-shaped tube packed with the solid adsorbent was placed in a thermostatic chamber at 25 ° C. A carbon dioxide / nitrogen mixed gas (carbon dioxide / nitrogen = 15 / 85 (v / v)) containing 100 ppm of sulfur dioxide was conditioned to a relative humidity of 90%. The same anion exchanger packed column as in Example 1 was placed in a thermostatic chamber at 40 ° C., and the conditioned mixed gas was supplied to this anion exchanger packed column at a flow rate of 0.5 L / min. Thereafter, the carbon dioxide-containing gas discharged from the anion exchanger packed column was supplied from one side of the U-shaped tube, and the carbon dioxide in the gas was adsorbed by the solid adsorbent. The carbon dioxide concentrations in the gas supplied from the supply port of the U-shaped tube and the gas discharged from the outlet of the U-shaped tube were continuously measured using a gas analyzer (PG-350, manufactured by Horiba, Ltd.), and the amount of carbon dioxide adsorption by the solid adsorbent was measured from the difference in carbon dioxide concentrations at the supply port and the outlet. The amount of carbon dioxide adsorption at the point when the carbon dioxide concentration at the outlet of the U-shaped tube matched the carbon dioxide concentration at the supply port was taken as the saturated adsorption amount of the solid adsorbent. The saturated adsorption amount was 70 g per kg of the solid adsorbent.

[0097] Next, the temperature of the thermostatic chamber in which the U-shaped tube was installed was raised to 50°C, and the amount of carbon dioxide desorbed from the solid adsorbent was measured. The amount of carbon dioxide desorbed was 50 g per kg of solid adsorbent. The above carbon dioxide adsorption / desorption cycle was repeated 50 times. Since the amount of carbon dioxide desorbed in the 50th cycle was 47 g, it was confirmed that this method can maintain the same amount of carbon dioxide recovered as the first time, even if carbon dioxide adsorption and desorption are repeatedly performed.

[0098] Comparative Example 2 Without using an anion exchanger packed column, a mixed gas conditioned to the same relative humidity as in Example 9 was supplied to the U-shaped tube used in Example 9. When carbon dioxide adsorption / desorption cycles were repeated in the same manner as in Example 9, it was confirmed that the amount of carbon dioxide desorbed decreased with each cycle, and that the amount of carbon dioxide desorbed had decreased to 38 g by the 50th cycle.

[0099] Carbon Dioxide Separation and Capture System Combining Anion Exchanger Packed Column and Membrane Separation Example 10 3 g of polyvinyl alcohol (molecular weight approximately 60,000, manufactured by Aldrich) as a water-soluble polymer was dissolved in 582 g of pure water, and 15 g of N-(2-aminoethyl)ethanolamine (manufactured by Tokyo Chemical Industry Co., Ltd.) was added to prepare a mixed solution. Next, the mixed solution was introduced into the primary side of a hollow fiber membrane module (manufactured by Kitz Microfilter Corporation, hollow fiber membrane inner diameter 0.36 mm) that communicates with the hollow fiber membrane, and the solution was allowed to pass for 10 minutes. Next, the hollow fiber membrane module that had been subjected to the liquid passing treatment was dried at 20°C under atmospheric air for 24 hours, yielding a hollow fiber membrane module in which a separation functional layer was formed on the inside (inner surface) of the hollow fiber membrane.

[0100] A carbon dioxide / nitrogen mixed gas (carbon dioxide / nitrogen = 15 / 85 (v / v)) containing 100 ppm of sulfur dioxide was conditioned to a relative humidity of 90%. The same anion exchanger packed column as in Example 1 was placed in a thermostatic bath at 40°C, and the conditioned mixed gas was supplied to this anion exchanger packed column. Thereafter, the carbon dioxide-containing gas discharged from the anion exchanger packed column was supplied to the hollow fiber membrane module, and carbon dioxide separation was carried out under the following conditions.

[0101] Supply gas flow rate: 700 mL / min Measurement temperature: 40°C Permeation side sweep gas: Helium Sweep gas flow rate: 470 mL / min Relative humidity: 90% Pressure (abs): supply side = 105 kPa, permeation side = 105 kPa

[0102] The carbon dioxide and nitrogen permeation fluxes immediately after the mixed gas supply were 150 GPU and 1.2 GPU, respectively. The carbon dioxide selectivity coefficient, which is the ratio of the carbon dioxide permeation flux to the nitrogen permeation flux, was 125.

[0103] Subsequently, the mixed gas was continuously supplied for 60 hours, and the permeation fluxes of carbon dioxide and nitrogen were measured. 60 hours after the start of the mixed gas supply, the permeation fluxes of carbon dioxide and nitrogen were 145 GPU and 1.2 GPU, respectively. The carbon dioxide selectivity coefficient was 120, and no deterioration in separation performance over time was observed.

[0104] (Comparative Example 3) Without using an anion exchanger packed column, a mixed gas conditioned to the same relative humidity as in Example 10 was supplied to the hollow fiber membrane module used in Example 10. The carbon dioxide permeation flux began to decrease immediately after the mixed gas was supplied, and had decreased to 45 GPU 5 hours after the start of the mixed gas supply.

[0105] As described above, the present disclosure provides a method for removing nitrogen oxides and / or sulfur oxides from a gas to be treated, which involves the simple operation of supplying the gas to be treated, containing nitrogen oxides and / or sulfur oxides and carbon dioxide, to an anion exchanger packed column. The present disclosure also provides a nitrogen oxide and / or sulfur oxide removal system utilizing this method. Additionally, by applying the above-described method for removing nitrogen oxides and / or sulfur oxides, a method for efficiently separating and capturing carbon dioxide can be provided, and a carbon dioxide separation and capture system utilizing this method can also be provided.

Claims

1. A method for removing nitrogen oxides and / or sulfur oxides from a gas to be treated which contains nitrogen oxides and / or sulfur oxides and carbon dioxide, comprising a gas supplying step of supplying the gas to be treated to an anion exchanger packed tower packed with an anion exchanger.

2. A method for removing nitrogen oxides and / or sulfur oxides according to claim 1, further comprising a temperature control step of controlling the temperature of the anion exchanger within a range of 20°C or higher and 100°C or lower.

3. A method for removing nitrogen oxides and / or sulfur oxides according to claim 1, comprising a condition control step of controlling one or more conditions selected from the group consisting of flow rate, temperature, and humidity of the gas to be treated.

4. A system for removing nitrogen oxides and / or sulfur oxides from a gas to be treated which contains nitrogen oxides and / or sulfur oxides and carbon dioxide, comprising: a condition control unit which controls one or more conditions selected from the group consisting of the flow rate, temperature and humidity of the gas to be treated; an anion exchanger packed tower which is filled with anion exchanger and to which the gas to be treated, the conditions of which are controlled by the condition control unit, is supplied; and a temperature control unit which controls the temperature of the anion exchanger to a range of 20°C or higher and 100°C or lower.

5. A system for separating and recovering carbon dioxide comprising: an anion exchanger packed tower packed with anion exchanger, to which a gas to be treated containing nitrogen oxides and / or sulfur oxides and carbon dioxide is supplied and which discharges a carbon dioxide-containing gas; a temperature control section which controls the temperature of the anion exchanger within the range of 20°C or higher and 100°C or lower; and a carbon dioxide separation and recovery section which separates and recovers carbon dioxide from the carbon dioxide-containing gas by one or more methods selected from the group consisting of an absorption method, an adsorption method, and a membrane separation method.

6. The carbon dioxide separation and capture system according to claim 5, further comprising a condition control unit that controls one or more conditions selected from the group consisting of flow rate, temperature, and humidity of the gas to be treated.

7. The carbon dioxide separation and capture system according to claim 5, wherein the carbon dioxide separation and capture unit is a unit that separates carbon dioxide at least by the absorption method and has a carbon dioxide absorption unit provided with an amine compound solution and a first carbon dioxide desorption unit provided with a heating device, the carbon dioxide absorption unit is a unit that absorbs carbon dioxide in the carbon dioxide-containing gas into the amine compound solution by contacting the amine compound solution with the carbon dioxide-containing gas, and the first carbon dioxide desorption unit is a unit that desorbs carbon dioxide from the amine compound solution by heating the amine compound solution that has absorbed carbon dioxide with the heating device.

8. The carbon dioxide separation and capture system according to claim 5, wherein the carbon dioxide separation and capture unit is a unit that separates carbon dioxide at least by the adsorption method, and has a carbon dioxide adsorption unit equipped with a solid adsorbent material in which a carbon dioxide carrier is supported on a porous support material, and a second carbon dioxide desorption unit equipped with a heating device and / or a pressure reduction device, the carbon dioxide adsorption unit is a unit that adsorbs carbon dioxide in the carbon dioxide-containing gas onto the solid adsorbent material by contacting the solid adsorbent material with the carbon dioxide-containing gas, and the second carbon dioxide desorption unit is a unit that desorbs carbon dioxide from the solid adsorbent material by heating the solid adsorbent material that has adsorbed carbon dioxide with the heating device and / or placing it under reduced pressure conditions with the pressure reduction device.

9. The carbon dioxide separation and capture system according to claim 5, wherein the carbon dioxide separation and capture section is a section that separates and captures carbon dioxide by at least the membrane separation method, and has a facilitated transport membrane into which a carbon dioxide carrier has been introduced.

10. A method for separating and capturing carbon dioxide, comprising a separation and capture step of separating and capturing carbon dioxide from the gas to be treated using the carbon dioxide separation and capture system according to any one of claims 5 to 9.

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