Acid gas recovery system

Abstract

The invention provides an acid gas recovery system capable of increasing the adsorption amount of acid gas and inhibiting deterioration of an acid gas adsorption material. An acid gas recovery system according to an embodiment of the present invention is provided with a plurality of acid gas adsorption devices including an acid gas adsorption material, and a fluid supply line. The fluid supply line distributes and supplies a fluid to each of the plurality of acid gas adsorption devices. The fluid supply line includes a branch portion and a plurality of shunt portions. And the branch parts are respectively connected with the acid gas adsorption devices through the plurality of flow dividing parts. Each of the plurality of flow dividing parts is provided with a resistance body.

Description

Technical Field

[0001] The present invention relates to an acid gas recovery system. Background Art

[0002] In recent years, efforts have been made to separate and recover acidic gases contained in the atmosphere in order to reduce environmental load. The main acidic gases include carbon dioxide (hereinafter sometimes referred to as CO 2 As a representative example of the above efforts, a carbon dioxide capture, utilization and storage (CCUS) cycle is known. As a carbon dioxide adsorption device used in such separation and recovery of carbon dioxide, a gas separation unit is proposed, which includes an adsorption material layer filled with a granular carbon dioxide adsorption material (for example, see Patent Document 1). In the gas separation unit, the granular carbon dioxide adsorption material adsorbs CO2 from a gas fluid passing through the adsorption material layer at a predetermined adsorption temperature. 2 When heated to a desorption temperature exceeding the adsorption temperature, the adsorbed CO 2 To provide CO cheaply 2 Recovery system, considering CO reduction 2 The number of supply blowers and the desorbed gas to multiple CO 2 However, multiple CO 2 The flow resistance (pressure loss) of the adsorption devices may be different from each other. In this case, in the desorption process, the CO with relatively small flow resistance is 2 The flow rate of the desorbed gas from the adsorption device is relatively large, which is suitable for CO with relatively large flow resistance. 2 The flow rate of the desorbed gas from the adsorption device becomes relatively small. 2 The temperature is uneven between the adsorption devices, and the flow resistance is relatively small. 2 The temperature of the adsorption unit may rise excessively. 2 If the temperature of the adsorption device rises excessively, the CO 2 The adsorbent material deteriorates due to volatilization and thermal decomposition, CO 2 The adsorption capacity of CO is reduced. In addition, the flow resistance is relatively large 2 The adsorption device has the following problems: the temperature is low and CO 2 The temperature required for separation, CO 2 The adsorption capacity decreased.

[0003] Prior art literature

[0004] Patent Literature

[0005] Patent Document 1: International Publication No. 2014 / 170184 Summary of the invention

[0006] A main object of the present invention is to provide an acid gas recovery system capable of increasing the amount of acid gas adsorbed and suppressing degradation of an acid gas adsorbent.

[0007] [1] An acid gas recovery system according to an embodiment of the present invention comprises: a plurality of acid gas adsorption devices, and a fluid supply line. The plurality of acid gas adsorption devices respectively contain an acid gas adsorption material. The fluid supply line distributes and supplies the fluid to the plurality of acid gas adsorption devices respectively. The fluid supply line comprises: a branch portion, and a plurality of diversion portions. The plurality of diversion portions respectively connect the branch portion and the plurality of acid gas adsorption devices. A resistance body is respectively provided in the plurality of diversion portions.

[0008] [2] In the acid gas recovery system described in [1] above, the acid gas may be carbon dioxide.

[0009] [3] The acid gas recovery system described in [1] or [2] above may be capable of performing the following steps: an adsorption step in which a gas to be treated containing acid gas is supplied to the plurality of acid gas adsorption devices so that the acid gas is adsorbed by the acid gas adsorption material; and a desorption step in which the plurality of acid gas adsorption devices are heated so that the acid gas is desorbed from the acid gas adsorption material, and the desorbed gas is supplied to the plurality of acid gas adsorption devices. In the desorption step, the flow path resistance of the resistor is greater than the flow path resistance of each of the plurality of acid gas adsorption devices.

[0010] [4] In the acid gas recovery system described in [3] above, the resistor may be capable of changing the flow resistance. In the adsorption step, the flow resistance of the resistor is smaller than the flow resistance of each of the plurality of acid gas adsorption devices.

[0011] [5] The acid gas recovery system described in [4] above may further include a control unit. The control unit is capable of controlling the flow path resistance of the resistor.

[0012] [6] The acid gas recovery system described in any one of [3] to [5] above may further include: a detour line capable of bypassing the above-mentioned resistance body.

[0013] Effects of the Invention

[0014] According to the embodiment of the present invention, it is possible to realize an acid gas recovery system capable of increasing the amount of acid gas adsorbed and suppressing the degradation of an acid gas adsorbent. BRIEF DESCRIPTION OF THE DRAWINGS

[0015] Figure 1 This is a schematic configuration diagram of an acid gas recovery system according to one embodiment of the present invention.

[0016] Figure 2 yes Figure 1 A schematic diagram of an embodiment of an acid gas adsorption device included in an acid gas recovery system.

[0017] Figure 3 yes Figure 1 A schematic perspective view of another embodiment of an acid gas adsorption device included in an acid gas recovery system.

[0018] Figure 4 yes Figure 3 A schematic cross-sectional view of an acid gas adsorption device.

[0019] Figure 5 This is a schematic configuration diagram of an acid gas recovery system according to another embodiment of the present invention. DETAILED DESCRIPTION

[0020] Hereinafter, embodiments of the present invention will be described with reference to the accompanying drawings, but the present invention is not limited to these embodiments. In addition, in order to make the description clearer, the accompanying drawings sometimes schematically show the width, thickness, shape, etc. of each part compared with the embodiments, but this is only an example and does not limit the interpretation of the present invention.

[0021] A. Overview of Acid Gas Recovery System

[0022] Figure 1 This is a schematic configuration diagram of an acid gas recovery system according to one embodiment of the present invention.

[0023] The acid gas recovery system 100 shown in the figure includes: a plurality of acid gas adsorption devices 1, and a fluid supply line 3. The plurality of acid gas adsorption devices 1 each include an acid gas adsorption material. The fluid supply line 3 distributes and supplies the fluid to the plurality of acid gas adsorption devices 1. The fluid supply line 3 includes: a branch portion 32, and a plurality of flow diversion portions 33. The plurality of flow diversion portions 33 respectively connect the branch portion 32 and the plurality of acid gas adsorption devices 1. A resistor 5 is provided in each of the plurality of flow diversion portions 33.

[0024] Typically, the acid gas recovery system 100 can perform an adsorption process and a desorption process. As described in detail below, in the adsorption process, a gas to be treated containing an acid gas is supplied to a plurality of acid gas adsorption devices 1 so that the acid gas is adsorbed by the acid gas adsorption material. In the desorption process, the plurality of acid gas adsorption devices 1 are heated so that the acid gas is desorbed from the acid gas adsorption material, and the desorbed gas is supplied to the plurality of acid gas adsorption devices 1.

[0025] According to one embodiment of the present invention, a plurality of acid gas adsorption devices 1 are connected to a fluid supply line 3 in parallel. The fluid supply line 3 can distribute and supply the gas to be treated to the plurality of acid gas adsorption devices 1 in the adsorption process. As a result, the acid gas can be adsorbed by the acid gas adsorption materials of the plurality of acid gas adsorption devices 1 at once, and the number of air blowers for supplying the acid gas can be reduced, so that the acid gas recovery system can be provided inexpensively. In addition, in the desorption process, the plurality of acid gas adsorption devices 1 are heated, and the fluid supply line 3 distributes and supplies the desorbed gas to the plurality of acid gas adsorption devices 1.

[0026] However, the flow resistance (pressure loss) of multiple acid gas adsorption devices is sometimes different from each other. In this case, in the desorption process, the flow rate of the desorbed gas to the acid gas adsorption device with a relatively small flow resistance becomes relatively large, and the flow rate of the desorbed gas to the acid gas adsorption device with a relatively large flow resistance becomes relatively small. As a result, temperature unevenness occurs among the multiple acid gas adsorption devices according to the flow rate of the desorbed gas, and the temperature of the acid gas adsorption device with a relatively small flow resistance may rise excessively. If the temperature of the acid gas adsorption device rises excessively, the acid gas adsorption material deteriorates due to volatilization and thermal decomposition, etc., and the adsorption capacity of the acid gas is reduced. In addition, in the acid gas adsorption device with a relatively large flow resistance, the temperature is low and the temperature required for acid gas desorption is not reached, and the adsorption capacity of the acid gas is reduced.

[0027] In this regard, in one embodiment of the present invention, a resistor 5 is provided in the flow distribution section 33 connecting the branch section 32 and each acid gas adsorbing device 1. Therefore, the flow rate of the desorbed gas flowing through each acid gas adsorbing device 1 depends more on the flow resistance of the resistor 5 than on the flow resistance (pressure loss) of the plurality of acid gas adsorbing devices 1. As a result, in the desorbing process, the flow rate of the desorbed gas flowing through each acid gas adsorbing device 1 can be made uniform, thereby suppressing an excessive increase in the temperature of the acid gas adsorbing device 1 and even deterioration of the acid gas adsorbing material.

[0028] In one embodiment, the flow resistance of the resistor 5 in the separation process is greater than the flow resistance of each of the multiple acid gas adsorption devices 1. The flow resistance of the resistor 5 in the separation process is, for example, 0.001 kPaG (gauge pressure) or more, preferably 0.1 kPaG or more, for example, 5 kPaG or less, preferably 1 kPaG or less. The flow resistance is a pressure loss resistance, and can be measured, for example, by a differential pressure gauge set before and after the resistor and before and after the acid gas adsorption device. The difference between the flow resistance of the resistor 5 and the flow resistance of the acid gas adsorption device 1 is, for example, 0.01 kPaG (gauge pressure) or more, preferably 0.1 kPaG or more, for example, 4.5 kPaG or less, preferably 0.9 kPaG or less.

[0029] If the flow resistance of the resistor in the desorption process and / or the difference in flow resistance between the resistor and the acid gas adsorption device is greater than the above lower limit, the flow resistance of the acid gas adsorption device can be stably suppressed from affecting the flow rate of the desorption gas. If the flow resistance of the resistor in the desorption process and / or the difference in flow resistance between the resistor and the acid gas adsorption device is less than the above upper limit, the desorption gas can be supplied to the acid gas adsorption device within an energetically feasible range in the desorption process.

[0030] In the desorption process, the friction loss coefficient of the resistance body 5 through which the desorption gas passes is, for example, 0.020 to 2.000, preferably 0.023 to 1.500. Typically, the friction loss coefficient is obtained from the Colebrook equation or the Moody diagram.

[0031] In the desorption process, the friction loss coefficient of the acidic gas adsorption device 1 through which the desorbed gas passes is, for example, 0.010 to 0.500, or preferably 0.015 to 0.350.

[0032] In one embodiment, the resistor 5 can change the flow resistance. The lower the flow resistance of the resistor 5 in the adsorption process, the more ideal it is, and representatively, it is smaller than the flow resistance of the resistor 5 in the separation process. The flow resistance of the resistor 5 in the adsorption process is, for example, 20 kPaG (gauge pressure) or less, preferably 1 kPaG or less, more preferably 0.1 kPaG or less, further preferably 0.08 kPaG or less, and particularly preferably 0.0008 kPaG or less. If the flow resistance of the resistor in the adsorption process is below the above upper limit, the gas to be treated can be efficiently supplied to each acid gas adsorption device in the adsorption process. It should be noted that the lower limit of the flow resistance of the resistor in the adsorption process is, for example, 0.0001 kPaG or more, and another example is 0.01 kPaG or more.

[0033] In one embodiment, the flow resistance of the resistor 5 in the adsorption step is smaller than the flow resistance of each of the plurality of acid gas adsorption devices 1. Thus, the gas to be treated can be supplied to the acid gas adsorption devices more efficiently.

[0034] In the adsorption process, the friction loss coefficient of the resistance body 5 through which the gas to be treated passes is, for example, 0.010 to 0.050, or preferably 0.015 to 0.045.

[0035] In the adsorption process, the friction loss coefficient of the acid gas adsorption device 1 through which the gas to be treated passes is, for example, 0.010 to 0.050, and preferably 0.013 to 0.045.

[0036] In addition, if Figure 5 As shown, the acid gas recovery system 100 may further include a detour line 34 that bypasses the resistor 5. Thus, if the flow path is switched, the resistor 5 can be bypassed. Therefore, in the adsorption process, the gas to be treated can be efficiently supplied to each acid gas adsorption device via the detour line. In this case, the flow path resistance (pressure loss) of the resistor 5 can be constant in the adsorption process and the desorption process. When the flow path resistance of the resistor 5 is constant, its range is, for example, the same as the range of the flow path resistance of the resistor 5 in the above-mentioned desorption process.

[0037] Examples of acidic gases included in the gas to be treated include carbon dioxide (CO 2 ), hydrogen sulfide, sulfur dioxide, nitrogen dioxide, dimethyl sulfide (DMS), hydrogen chloride, etc. In one embodiment, the acidic gas is carbon dioxide (CO 2 ), the gas to be treated contains CO 2 Gas. Contains CO 2 The gas may contain CO 2 In addition, it also contains nitrogen. 2 Gas, typically air (atmosphere). Contains CO 2 CO in gas 2 The concentration is, for example, 100 ppm (volume basis) or more and 2 volume % or less.

[0038] In the following, the acid gas is carbon dioxide (CO 2 ) is described in detail.

[0039] B. Details of the Acid Gas Recovery System

[0040] Next, refer to Figure 1 , the details of the acid gas recovery system 100 are described.

[0041] The acid gas recovery system 100 shown in the figure is provided with the above-mentioned multiple acid gas adsorption devices 1, fluid supply lines 3 and multiple resistors 5, and further includes: an acid gas supply blower 2, a degassing gas supply unit 6, and a recovery unit 4. The gas to be treated by the acid gas adsorption device is CO 2 In the case of the acid gas, the acid gas adsorption device 1 is a carbon dioxide adsorption device 1a.

[0042] The acid gas recovery system 100 shown in the figure includes four acid gas adsorption devices 1, but the number of acid gas adsorption devices 1 is not limited thereto. The number of acid gas adsorption devices 1 is, for example, 2 or more, preferably 4 or more, and for example, 10 or less.

[0043] B-1. First Embodiment of Acid Gas Adsorption Device

[0044] In one embodiment, if Figure 2 As shown, the acid gas adsorbing device 1 includes a plurality of adsorbent layers 71 .

[0045] The plurality of adsorbent layers 71 are stacked with a gap in the thickness direction thereof. In the example shown in the figure, five adsorbent layers 71 are arranged in parallel, but the number of adsorbent layers 71 is not limited thereto. The number of adsorbent layers 71 is, for example, 5 or more, preferably 10 or more, and more preferably 20 or more. The gap between adjacent adsorbent layers 71 in the plurality of adsorbent layers 71 is, for example, 0.5 cm or more and 1.5 cm or less.

[0046] Each of the plurality of adsorbent layers 71 includes a flexible fiber member 73 and a plurality of granular adsorbents 72 .

[0047] The flexible fiber component 73 allows the passage of gas and restricts the passage of the granular adsorbent material. Typically, the flexible fiber component 73 is formed into a hollow shape (bag shape) capable of accommodating a plurality of granular adsorbent materials 72. The flexible fiber component 73 may be a fabric or a non-woven fabric. Examples of the material of the flexible fiber component 73 include organic fibers and natural fibers, preferably polyethylene terephthalate fibers, polyethylene fibers, and cellulose fibers. The thickness of the flexible fiber component 73 is, for example, not less than 25 μm and not more than 500 μm.

[0048] A plurality of granular adsorbent materials 72 are filled in the interior of a flexible fiber member 73 having a hollow shape (bag shape). The granular adsorbent material 72 functions as an acid gas adsorbent, and typically functions as a carbon dioxide adsorbent. As the material of the granular adsorbent 72, for example, an amine-modified material can be cited, preferably amine-modified cellulose can be cited, and more preferably amine-modified nanofibrillated cellulose can be cited. The average primary particle size of the granular adsorbent material 72 is, for example, not less than 60 μm and not more than 1200 μm. The filling ratio of the granular adsorbent material 72 in the adsorbent layer 71 can adopt any appropriate value.

[0049] The acid gas adsorption device 1 shown in the figure further includes a plurality of spacers 74. The spacers 74 are sandwiched between the adjacent adsorption material layers 71 among the plurality of adsorption material layers 71. Thus, the spacing between the adjacent adsorption material layers can be stably ensured. In one embodiment, the plurality of adsorption material layers 71 and the plurality of spacers 74 are arranged such that: from a direction orthogonal to the thickness direction of the adsorption material layer 71 ( Figure 1 When viewed in the depth direction of the paper, it becomes a roughly Z shape.

[0050] As such an acid gas adsorption device 1, for example, there can be mentioned a gas separation unit described in International Publication No. 2014 / 170184, the entire contents of which are incorporated herein by reference.

[0051] B-2. Second Embodiment of Acid Gas Adsorption Device

[0052] In another embodiment, if Figure 3 and Figure 4 As shown, the acid gas adsorption device 1 includes a substrate 10 and an acid gas adsorption layer 15 .

[0053] The structure of the substrate 10 is not particularly limited, and examples thereof include a honeycomb structure, a filter structure such as filter cloth, and a particle structure. The acid gas adsorption layer 15 may be disposed on the surface of the substrate 10 and is not particularly limited.

[0054] B-2-1. Base material (honeycomb base material)

[0055] In one embodiment, the substrate 10 is a honeycomb substrate 10 a . The honeycomb substrate 10 a includes partition walls 13 defining a plurality of cells 14 .

[0056] The cells 14 extend from the first end face E1 (inflow end face) to the second end face E2 (outflow end face) of the honeycomb substrate 10a in the longitudinal direction (axial direction) of the honeycomb substrate 10a (see Figure 4). The cell 14 has any appropriate shape in the cross section of the honeycomb substrate 10a in a direction perpendicular to the length direction. Examples of the cross-sectional shape of the cell include: a triangle, a quadrilateral, a pentagon, a polygon larger than a hexagon, a circle, and an ellipse. The cross-sectional shape and size of the cell may be all the same or at least partially different. Among the cross-sectional shapes of such cells, preferably a hexagon or a quadrilateral can be mentioned, and more preferably a square, a rectangle or a hexagon can be mentioned.

[0057] The cell density in the cross section of the honeycomb substrate in a direction perpendicular to the longitudinal direction (i.e., the number of cells 14 per unit area) can be appropriately set according to the purpose. For example, the cell density can be 4 cells / cm 2 ~320 compartments / cm 2 When the cell density is within such a range, the strength and effective GSA (geometric surface area) of the honeycomb substrate can be sufficiently ensured.

[0058] The honeycomb substrate 10a has any appropriate shape (overall shape). Examples of the shape of the honeycomb substrate include: a cylindrical shape with a circular bottom surface, an elliptical cylindrical shape with an elliptical bottom surface, a prism shape with a polygonal bottom surface, and a column shape with an irregular bottom surface. The honeycomb substrate 10a shown in the figure has a cylindrical shape. The outer diameter and length of the honeycomb substrate can be appropriately set according to the purpose. Although not shown in the figure, the honeycomb substrate may have a hollow area in the center of the cross section in a direction perpendicular to the longitudinal direction.

[0059] Typically, the honeycomb substrate 10a includes an outer peripheral wall 11 and partition walls 13 located inside the outer peripheral wall 11. In the example shown in the figure, the outer peripheral wall 11 and the partition walls 13 are formed integrally. The outer peripheral wall 11 and the partition walls 13 may be separate bodies.

[0060] The outer peripheral wall 11 has a cylindrical shape. The thickness of the outer peripheral wall 11 can be set arbitrarily and appropriately. The thickness of the outer peripheral wall 11 is, for example, 0.1 mm to 10 mm.

[0061] The partition wall 13 defines a plurality of compartments 14. More specifically, the partition wall 13 includes a first partition wall 13a and a second partition wall 13b that are orthogonal to each other, and the first partition wall 13a and the second partition wall 13b define a plurality of compartments 14. The cross-sectional shape of the compartment 14 is a quadrilateral except for the portion where the first partition wall 13a and the second partition wall 13b contact the outer peripheral wall 11. It should be noted that the configuration of the partition wall is not limited to the above-mentioned partition wall 13. The partition wall may include: a first partition wall extending in a radial direction, and a second partition wall extending in a circumferential direction, which define a plurality of compartments.

[0062] The thickness of the partition wall 13 can be appropriately set according to the purpose of the honeycomb substrate. Typically, the thickness of the partition wall 13 is thinner than the thickness of the peripheral wall 11. The thickness of the partition wall 13 is, for example, 0.03 mm to 0.6 mm. The thickness of the partition wall is measured by, for example, cross-sectional observation based on SEM (scanning electron microscope). If the thickness of the partition wall is within such a range, the mechanical strength of the honeycomb substrate can be sufficient, and the opening area (the total area of ​​the cells in the cross section) can be sufficient.

[0063] The porosity of the partition walls 13 can be appropriately set according to the purpose. The porosity of the partition walls 13 is, for example, 15% or more, preferably 20% or more, and for example, 70% or less, preferably 45% or less. The porosity can be measured by, for example, mercury penetration.

[0064] The bulk density of the partition walls 13 can be appropriately set according to the purpose. For example, the bulk density is 0.10 g / cm 3 Above, preferably 0.20 g / cm 3 Above, for example, 0.60 g / cm 3 Below, preferably 0.50g / cm 3 Hereinafter, the bulk density can be measured by, for example, mercury intrusion porosimetry.

[0065] As the material constituting the partition wall 13, representatively, ceramics can be cited. As ceramics, for example, silicon carbide, silicon-silicon carbide composite materials, cordierite, mullite, alumina, silicon nitride, spinel, silicon carbide-cordierite composite materials, lithium aluminum silicate and aluminum titanate can be cited. The material constituting the partition wall can be used alone or in combination. Among the materials constituting the partition wall, cordierite, alumina, mullite, silicon carbide, silicon-silicon carbide composite materials and silicon nitride can be preferably cited, and silicon carbide and silicon-silicon carbide composite materials can be more preferably cited.

[0066] Typically, such a honeycomb substrate 10a is produced by the following method. First, a binder and water or an organic solvent are added to the material powder containing the above-mentioned ceramic powder as needed, and the obtained mixture is kneaded to form a blank, and the blank is molded (typically extrusion molded) into a desired shape, and then dried and fired as needed to produce the honeycomb substrate 10a. In the case of firing, for example, the firing is performed at 1200°C to 1500°C. The firing time is, for example, 1 hour or more and 20 hours or less.

[0067] B-2-2. Acidic gas adsorption layer (carbon dioxide adsorption layer)

[0068] In one embodiment, the acid gas adsorption layer 15 is formed on the surface of the partition wall 13. In the honeycomb substrate 10a, a gas flow path 16 is formed in a portion (typically, a central portion) of the cross section of the cell 14 where the acid gas adsorption layer 15 is not formed. The acid gas adsorption layer 15 may be formed on the entire inner surface of the partition wall 13 (i.e., in a manner that surrounds the gas flow path 16) as shown in the example of the figure, or may be formed on a portion of the surface of the partition wall. If the acid gas adsorption layer 15 is formed on the entire inner surface of the partition wall 13, the acid gas (typically, CO 2 ) can be increased. 2 ) removal efficiency.

[0069] The gas flow path 16 extends from the first end face E1 (inflow end face) to the second end face E2 (outflow end face) in the same manner as the compartment 14. The cross-sectional shape of the gas flow path 16 may be the same as that of the compartment 14, preferably a hexagon or a quadrilateral, more preferably a square, a rectangle or a hexagon. The cross-sectional shape and size of the gas flow path 16 may be the same in all or may be at least partially different.

[0070] Typically, in the adsorption step, the above-mentioned gas to be treated flows through the cell 14 (more specifically, the gas flow path 16 ). In addition, in one embodiment, in the desorption step, the desorption gas flows through the cell 14 (more specifically, the gas flow path 16 ).

[0071] The acid gas adsorption layer 15 contains an acid gas adsorption material corresponding to the acid gas to be adsorbed. In one embodiment, the acid gas adsorption layer 15 is a carbon dioxide adsorption layer 15a. The carbon dioxide adsorption layer 15a contains a carbon dioxide adsorption material as an example of an acid gas adsorption material.

[0072] As carbon dioxide adsorbent materials, 2 Any appropriate compound that adsorbs and desorbs. Examples of carbon dioxide adsorbents include: nitrogen-containing compounds described below; alkaline compounds such as sodium hydroxide and potassium hydroxide; carbonates such as calcium carbonate and potassium carbonate; bicarbonates such as calcium hydrogen carbonate and potassium hydrogen carbonate; organometallic structures (MOFs) such as MOF-74, MOF-200, and MOF-210; zeolites; activated carbon; nitrogen-doped carbon; ionic liquids, etc. Carbon dioxide adsorbents can be used alone or in combination.

[0073] Among the carbon dioxide adsorbents, nitrogen-containing compounds and ionic liquids are preferred. More specifically, the nitrogen-containing compounds include: primary amines such as monoethanolamine and polyethyleneamine; secondary amines such as diethanolamine, cyclic amines, and N-(3-aminopropyl)diethanolamine; tertiary amines such as methyldiethylamine and triethanolamine; ethyleneamine compounds such as tetraethylenepentamine; aminosilane coupling agents such as aminopropyltrimethoxysilane, 3-aminopropyltriethoxysilane, N-(2-aminoethyl)-3-aminopropyl-trimethoxysilane, and polyethyleneimine-trimethoxysilane; organic monomers having primary to tertiary amino groups such as ethyleneimine and styrene endowed with amino groups; organic polymers having primary to tertiary amino groups such as linear polyethyleneimine and branched polyethyleneimine having primary to tertiary amino groups; piperazine compounds such as 1-(2-hydroxyethyl)piperazine; amide compounds such as polyamideamine; polyethyleneamine; and organic / inorganic compounds endowed with amino groups as substituents.

[0074] Among the nitrogen-containing compounds, preferred examples include methyldiethylamine, monoethanolamine, cyclic amines, diethanolamine, tetraethylenepentamine, ethyleneimine, linear polyethyleneimine, branched polyethyleneimine, and organic / inorganic compounds having an amino group as a substituent.

[0075] Ionic liquids are liquid "salts" composed only of ions (anions and cations), and are in a liquid state at normal temperature and pressure (23°C, 0.1 MPaA (absolute pressure)). Examples of cations of ionic liquids include: ammonium ions such as imidazolium salts and pyridinium salts, phosphonium ions, sulfonium salts, inorganic ions, and the like. Examples of anions of ionic liquids include: halogen ions such as bromide ions and trifluoromethanesulfonates; boron ions such as tetraphenylborate; phosphorus ions such as hexafluorophosphate; sulfur ions such as alkylsulfonates. Among ionic liquids, a combination of imidazolium salts as cations and trifluoromethanesulfonates as anions is preferred.

[0076] The ionic liquid is more preferably used in combination with a carbon dioxide adsorbent material other than the ionic liquid (hereinafter referred to as other carbon dioxide adsorbent material). In this case, the ionic liquid is coated with the other carbon dioxide adsorbent material (eg, a nitrogen-containing compound). Therefore, the performance of the carbon dioxide adsorbent material can be improved and the life can be extended.

[0077] The content ratio of the ionic liquid is, for example, 0.000001 parts by mass or more, preferably 0.00001 parts by mass or more, for example, 0.1 parts by mass or less, preferably 0.05 parts by mass or less, relative to 1 part by mass of other carbon dioxide adsorbents. If the content ratio of the ionic liquid is within the above range, the performance improvement and long life of the carbon dioxide adsorbent can be stably achieved.

[0078] In one embodiment, the carbon dioxide adsorption layer 15a further includes a porous carrier in addition to the above-mentioned carbon dioxide adsorption material. In this case, the carbon dioxide adsorption material is typically supported on the porous carrier and faces the gas flow path. If the carbon dioxide adsorption layer includes a porous carrier, it is possible to suppress the carbon dioxide adsorption material from falling off from the carbon dioxide adsorption layer during the adsorption process and / or the desorption process.

[0079] The porous carrier can form mesopores in the carbon dioxide adsorption layer. As the porous carrier, for example, there can be mentioned: organometallic structures (MOFs) such as MOF-74, MOF-200, and MOF-210; activated carbon; nitrogen-doped carbon; mesoporous silica; mesoporous alumina; zeolite; carbon nanotubes; fluorinated resins such as polyvinylidene fluoride (PVDF), preferably, there can be mentioned: organometallic structures (MOFs), PVDF, activated carbon, zeolite, mesoporous silica, and mesoporous alumina. The porous carrier can be used alone or in combination. The porous carrier preferably uses a material different from the carbon dioxide adsorbent material.

[0080] The BET specific surface area of ​​the porous carrier is, for example, 50 m 2 / g or more, preferably 500m 2 When the surface area of ​​the porous carrier is greater than or equal to the above lower limit, the carbon dioxide adsorbent can be stably supported, thereby increasing the CO 2 The upper limit of the BET specific surface area of ​​the porous carrier is typically 2000 m 2 / g or less.

[0081] When the carbon dioxide adsorption layer contains a carbon dioxide adsorbent and a porous carrier, the total content ratio of the carbon dioxide adsorbent and the porous carrier in the carbon dioxide adsorption layer is, for example, 30 mass % or more, preferably 50 mass % or more, for example, 100 mass % or less, preferably 99 mass % or less.

[0082] The content ratio of the carbon dioxide adsorbent in the carbon dioxide adsorption layer is, for example, 30% by mass or more, preferably 50% by mass or more, for example, 99% by mass or less. The content ratio of the porous carrier is, for example, 0.01% by mass or more, preferably 0.3% by mass or more, for example, 0.7% by mass or less, preferably 0.5% by mass or less, relative to 1% by mass of the carbon dioxide adsorbent. If the content ratio of the porous carrier is within the above range, the carbon dioxide adsorbent can be more stably supported.

[0083] In addition, the carbon dioxide adsorption layer may be composed only of the carbon dioxide adsorption material. In this case, the carbon dioxide adsorption material is directly supported on the partition wall 13 and faces the gas flow path. When the carbon dioxide adsorption layer is composed only of the carbon dioxide adsorption material, the content of the carbon dioxide adsorption material in the carbon dioxide adsorption layer is typically 95.0 mass % or more and 100 mass % or less. If the content of the carbon dioxide adsorption material is within the above range, it is possible to stably ensure excellent CO 2 Recovery rate.

[0084] Typically, such a carbon dioxide adsorption layer is produced by the following method. The above-mentioned carbon dioxide adsorption material is dissolved in a solvent to prepare a solution of the carbon dioxide adsorption material. In addition, the above-mentioned porous carrier is added to the solvent as needed. There is no particular restriction on the order of adding the carbon dioxide adsorption material and the porous carrier. Afterwards, the solution of the carbon dioxide adsorption material is applied to a substrate (specifically, a partition), and then the coating is dried and sintered as needed to form a carbon dioxide adsorption layer.

[0085] Alternatively, a dispersion containing a carbon dioxide adsorbent other than an ionic liquid and a porous carrier is applied to a substrate, the coating is dried, and if necessary, sintered, and then only the ionic liquid is applied to the substrate to form a carbon dioxide adsorbing layer.

[0086] Although not shown, the acid gas adsorption device 1 may include a heater in addition to the substrate 10 and the acid gas adsorption layer 15. The heater can heat the substrate 10. Typically, the heater is in contact with the substrate 10. If the acid gas adsorption device includes a heater, the temperature of the acid gas adsorption device can be smoothly raised to the desorption temperature in the desorption step.

[0087] Although not shown in the figure, the acid gas adsorption device 1 may include a housing. The housing has a cylindrical shape (hollow shape) extending along the direction in which the gas to be treated passes. Examples of the cylindrical shape include a cylindrical shape and a square cylindrical shape. One end of the housing is configured as an inlet, and the other end of the housing is configured as an outlet. Regarding the housing, in one embodiment, it accommodates a plurality of adsorption material layers 71 and a plurality of spacers 74 (see Figure 2 ), in another embodiment, the substrate 10 and the acid gas adsorption layer 15 are stored (refer to Figure 3 and Figure 4 ).

[0088] B-3. ​​Blower for acid gas supply

[0089] like Figure 1 As shown, the acid gas supply blower 2 is configured to supply the gas to be treated (typically containing CO) to the plurality of acid gas adsorption devices 1 during the adsorption process.2 The acid gas supply blower 2 shown in the figure can convey the to-be-treated gas containing the acid gas toward the plurality of acid gas adsorption devices 1. The acid gas supply blower 2 can adopt any appropriate configuration.

[0090] B-4. Fluid supply line

[0091] Typically, the fluid supply line 3 includes a connection portion 31 , a branch portion 32 , and a plurality of branching portions 33 .

[0092] The connection portion 31 is typically a pipe that connects the acid gas supply blower 2 and the branch portion 32 .

[0093] The branching part 32 is typically a manifold. Although not shown, the branching part 32 has an inlet and a plurality of outlets. The inlet is connected to the connection part 31. The number of the plurality of outlets is the same as the number of the plurality of acid gas adsorbing devices 1 included in the acid gas recovery system 100.

[0094] The plurality of flow dividing sections 33 are typically pipes that connect the branch section 32 and each of the acid gas adsorbing devices 1. In one embodiment, the flow dividing section 33 connects the outlet of the branch section 32 and the inlet of the housing of the acid gas adsorbing device 1.

[0095] B-5. Resistance body

[0096] As described above, the resistor 5 is provided in the flow separation section 33. The resistor 5 appropriately restricts the flow of the desorbed gas in the flow separation section 33 during the desorbing process. The resistor 5 only needs to have the above-mentioned flow resistance, and any appropriate structure may be adopted. Examples of the resistor 5 include: an orifice plate, a nonwoven fabric, a regulating valve, and a heat exchanger. Representatively, the plurality of resistors 5 provided in the acid gas recovery system 100 have substantially the same flow resistance in each process (specifically, within ±30% of the specified value or within ±5 kPaG (gauge pressure)).

[0097] As described above, when the resistance body 5 is configured to change the flow resistance, the acid gas recovery system 100 may further include a control unit 9. The control unit 9 can appropriately control the flow resistance of the resistance body 5. Typically, the control unit 9 is connected to each of the plurality of resistance bodies 5 in a communicable manner. The control unit 9 can send a signal instructing the resistance body 5 to change the flow resistance. The control unit 9 includes, for example, a central processing unit (CPU), a ROM, and a RAM.

[0098] B-6. Degassing gas supply unit

[0099] The desorption gas supply unit 6 is configured to supply desorption gas to the acid gas adsorption device 1 during the desorption process. The desorption gas supply unit 6 shown in the figure includes a desorption gas supply line 62 and an on-off valve 61. The desorption gas supply line 62 is typically a pipe capable of supplying the desorption gas to the fluid supply line 3. The downstream end of the desorption gas supply line 62 in the supply direction of the desorption gas is connected to the connection portion 31. In the case where the desorption gas is a recovered gas (described later), although not shown in the figure, the upstream end of the desorption gas supply line 62 in the supply direction of the desorption gas is connected to an intermediate tank for storing the desorption gas (representatively recovered gas). The on-off valve 61 is provided on the desorption gas supply line 62 and can open and close the desorption gas supply line 62. As the on-off valve 61, for example, a ball valve, a gate valve, and a butterfly valve can be cited, and preferably a butterfly valve can be cited.

[0100] B-7. Recovery Unit

[0101] The recovery unit 4 is configured to recover the acid gas separated in the separation process. The recovery unit 4 shown in the figure includes a suction pump 41 and a discharge line 42. The suction pump 41 can suck the gas in the acid gas adsorption device. As the suction pump 41, for example, a vacuum pump can be cited. The discharge line 42 is typically a pipe for the gas discharged from the plurality of acid gas adsorption devices 1 and passing toward the suction pump 41. The upstream end of the discharge line 42 in the direction in which the gas passes is branched into the same number as the plurality of acid gas adsorption devices 1, and is connected to each of the acid gas adsorption devices 1. In one embodiment, the upstream end (branch portion) of the discharge line 42 is connected to the flow outlet of the shell of each acid gas adsorption device 1. The downstream end of the discharge line 42 in the direction in which the gas passes is connected to the suction pump 41 after merging at the above-mentioned branch portion.

[0102] B-8. Detour Line

[0103] like Figure 5 As shown, the acid gas recovery system 100 may further include a detour line 34. The detour line 34 is configured such that, in the adsorption process, the gas to be treated bypasses the resistance body 5 and is supplied to the acid gas adsorption device 1. The detour line 34 is typically a pipe through which the gas can pass. In one embodiment, the acid gas recovery system 100 includes a plurality of detour lines 34. The plurality of detour lines 34 are respectively connected to a plurality of branch sections 33. An upstream end of the detour line 34 in the gas passing direction is connected to a portion between the branch section 32 and the resistance body 5 in the branch section 33. A downstream end of the detour line 34 in the gas passing direction is connected to a portion between the resistance body 5 and the acid gas adsorption device 1 in the branch section 33.

[0104] In the example shown in the figure, an on-off valve 35 is provided on the detour line 34. The on-off valve 35 can open and close the detour line 34. Examples of the on-off valve 35 include a ball valve, a gate valve, and a butterfly valve, and preferably a butterfly valve.

[0105] Such an on-off valve 35 may be electrically connected to the control unit 9. In this case, the control unit 9 can control the opening and closing of the on-off valve 35 instead of controlling the change of the flow path resistance of the resistor 5.

[0106] C. Operation of the Acid Gas Recovery System

[0107] Next, refer to Figure 1 , an embodiment of a method for recovering acid gas using the acid gas recovery system 100 is described. In one embodiment, the method for recovering acid gas includes: the above-mentioned adsorption step, the replacement step, and the above-mentioned desorption step in sequence.

[0108] In the acid gas recovery system 100, first, an adsorption process is implemented. In the adsorption process, the on-off valve 61 is set to a closed state, and the acid gas supply blower 2 is driven. As a result, the gas to be treated is sent out through the acid gas supply blower 2, and is distributed and supplied to each of the plurality of acid gas adsorption devices 1 through the fluid supply line 3. It should be noted that the temperature of each acid gas adsorption device in the adsorption process is pre-adjusted to the adsorption temperature. In addition, the flow path resistance of the resistor in the adsorption process is preferably pre-set to be less than the upper limit of the flow path resistance of the resistor in the adsorption process described above. In the example shown in the figure, the flow path resistance of the resistor 5 is pre-set as described above using a signal from the control unit 9.

[0109] The temperature of the gas to be treated supplied to the plurality of acid gas adsorbing devices is, for example, 0° C. to 50° C., preferably the same as the outside air temperature. The temperature of the gas to be treated may be the same as or different from the adsorption temperature of the acid gas adsorbing device.

[0110] The pressure of the gas to be treated is, for example, 0.3×10 5 PaA (absolute pressure) or above and 2.0×10 5 The flow rate of the treated gas sent by the acid gas supply blower is, for example, 1.0 m / sec to 30 m / sec, and the flow rate of the treated gas supplied to each acid gas adsorption device is, for example, 0.5 m / sec to 5 m / sec.

[0111] The temperature of each acid gas adsorption device in the adsorption process (adsorption temperature) is, for example, 0° C. or more, preferably 10° C. or more, for example, 50° C. or less, preferably 40° C. or less. In one embodiment, the adsorption temperature is the same as the external air temperature. The implementation time of the adsorption process (adsorption time) is, for example, 15 minutes or more, preferably 30 minutes or more, for example, 3 hours or less, preferably 2 hours or less.

[0112] When the adsorption temperature and / or the adsorption time are within the above ranges, the acid gas adsorbent can efficiently adsorb the acid gas.

[0113] Thereafter, when the above-mentioned adsorption time has elapsed, the driving of the acid gas supply blower 2 is stopped, and the adsorption process is completed.

[0114] The acid gas recovery rate in the adsorption process (=100-(acid gas concentration in the gas to be treated that has passed through multiple acid gas adsorption devices / acid gas concentration in the gas to be treated before being supplied to multiple acid gas adsorption devices×100)) is, for example, 60% or more, preferably 75% or more, more preferably 80% or more, for example, 90% or less.

[0115] Next, the replacement process is performed in the acid gas recovery system 100. In the replacement process, the on-off valve 61 is changed from a closed state to an open state, and the suction pump 41 is driven. Then, the desorbed gas passes through the desorbed gas supply line 62 and is supplied to the fluid supply line 3, and is distributed through the fluid supply line 3 and supplied to each of the plurality of acid gas adsorption devices 1. As a result, the interior of the acid gas adsorption device 1 (representatively, the gas flow path 16) is replaced from the gas to be treated to the desorbed gas.

[0116] In the replacement step, the temperature range of the desorbed gas supplied to each acid gas adsorbing device is the same as the above-mentioned adsorption temperature range. The pressure of the desorbed gas is, for example, 0.1×10 4 PaA (absolute pressure) or above and 1.0×10 4 PaA or less, for example, 0.1×10 4 PaA or above and 5.0×10 4 The implementation time of the replacement step (hereinafter referred to as replacement time) is, for example, 1 minute or more and 30 minutes or less.

[0117] It should be noted that in the replacement step, a purge gas different from the desorbed gas may be introduced into the acid gas adsorption device, thereby replacing the gas to be treated in the acid gas adsorption device with the purge gas. In this case, the pressure of the purge gas is, for example, 0.1×10 4 PaA or above and 11×10 4The replacement time is, for example, 1 minute or more and 30 minutes or less. Examples of the purge gas include water vapor, carbon dioxide, nitrogen, and argon.

[0118] Thereafter, in the acid gas recovery system 100 , a separation step is performed following the replacement step.

[0119] In the desorption step, the plurality of acid gas adsorption devices 1 are typically heated to a desorption temperature exceeding the adsorption temperature. It should be noted that the heating of the acid gas adsorption devices may be started in the middle of the replacement step.

[0120] In addition, it is preferred to set the flow resistance of the plurality of resistors to be greater than the lower limit of the flow resistance of the resistors in the above-mentioned desorption process. In the example shown in the figure, a signal is sent from the control unit 9 to each resistor 5, and based on the signal, the flow resistance of each resistor 5 is changed as described above. Next, the desorption gas is supplied to the plurality of acid gas adsorption devices 1 heated to the desorption temperature. In more detail, in the desorption process, the plurality of acid gas adsorption devices 1 are heated to the desorption temperature, maintained at the desorption temperature for a predetermined desorption time, and the desorption gas is supplied to each acid gas adsorption device. In the example shown in the figure, by maintaining the drive of the suction pump 41, the desorption gas is evenly distributed through the fluid supply line 3 and the resistor 5 and supplied to each of the plurality of acid gas adsorption devices 1. As a result, the desorbed acid gas is recovered together with the desorption gas. The gas recovered in the desorption process is sometimes referred to as recovered gas.

[0121] As the desorbed gas, preferably, the recovered gas previously recovered by the acid gas recovery system can be cited. By using the recovered gas as the desorbed gas, the acid gas concentration in the recovered gas can be increased. The oxygen concentration in the recovered gas is preferably 15 volume % or less.

[0122] The temperature of the desorbed gas supplied to the acid gas adsorption device is, for example, 60° C. or higher, preferably 90° C. or higher, and for example, 200° C. or lower, preferably 160° C. or lower.

[0123] The temperature of the acid gas adsorption device in the desorption step (desorption temperature) is, for example, 70° C. or higher, preferably 80° C. or higher, and for example, 200° C. or lower, preferably 110° C. or lower.

[0124] The implementation time of the desorption process (the desorption time during which the acid gas adsorbent is maintained at the desorption temperature) is, for example, 1 minute or more, preferably 5 minutes or more, for example, 1 hour or less, preferably 30 minutes or less. If the desorption temperature and / or the desorption time are within the above range, the acid gas can be desorbed more smoothly from the acid gas adsorbent.

[0125] As described above, when the temperature of each acid gas adsorbing device reaches the desorption temperature, the acid gas retained by the acid gas adsorbing material is desorbed (released) from the acid gas adsorbing material. The desorbed acid gas is discharged from the acid gas adsorbing device 1 together with the desorbed gas, passes through the discharge line 42 and the suction pump 41, and is stored in an intermediate tank as needed. Such recovered gas can be used for various purposes, and can be supplied to the acid gas adsorbing device again as the desorbed gas as described above, or can be used as a raw material for various industrial products (for example, a raw material for hydrocarbon fuel).

[0126] Afterwards, the acid gas recovery system 100 performs the adsorption process again as needed. More specifically, the drive of the suction pump 41 is stopped, and then the above-mentioned adsorption process is performed again. In this way, the acid gas recovery system 100 can repeat the adsorption process, the replacement process, and the desorption process in sequence.

[0127] In addition, if Figure 5 As shown, when the acid gas recovery system 100 is provided with the bypass line 34, in the adsorption process, the on-off valve 61 is set to the closed state, the on-off valve 35 is set to the open state, and the acid gas supply blower 2 is driven. Then, due to the flow resistance of the resistor 5, the flow rate of the gas to be treated passing through the bypass line 34 is greater than the flow rate of the gas to be treated passing through the branching portion 33. Therefore, the above-mentioned gas to be treated passes through the bypass line 34 and is smoothly supplied to the acid gas adsorption device 1.

[0128] After that, after the above-mentioned adsorption time has passed, the driving of the acid gas supply blower 2 is stopped. Next, the replacement process is performed, the on-off valve 61 is changed from the closed state to the open state, and the on-off valve 35 is maintained in the open state, and the suction pump 41 is driven. Then, the above-mentioned desorbed gas passes through the bypass line 34 and is supplied to the acid gas adsorbing device 1. As a result, the inside of the acid gas adsorbing device 1 (representatively, the gas flow path 16) is replaced from the gas to be treated to the desorbed gas.

[0129] After the replacement time has passed, the desorption process is performed, the on-off valve 61 is maintained in the open state, and the on-off valve 35 is changed from the open state to the closed state. As a result, the desorption gas is restricted from passing through the bypass line 34, and thus passes through the resistor 5 and is supplied to the acid gas adsorption device 1 heated to the desorption temperature. Therefore, the flow rate of the desorption gas flowing through each acid gas adsorption device 1 can be made uniform, and the recovery gas containing the acid gas and the desorption gas can be smoothly recovered.

[0130] Industrial Applicability

[0131] The acid gas recovery system according to the embodiment of the present invention is used for separation and recovery of acid gas, and can be particularly well used in a carbon dioxide recovery, utilization and storage (CCUS) cycle.

[0132] Explanation of symbols

[0133] 1Acid gas adsorption device

[0134] 1a Carbon dioxide adsorption device

[0135] 3 Fluid supply lines

[0136] 32 Branches

[0137] 33 Diversion

[0138] 34 Detour Line

[0139] 100 Acid Gas Recovery System

[0140] 100a Carbon dioxide recovery system

Claims

1. An acid gas recovery system, comprising: a plurality of acid gas adsorption devices, the plurality of acid gas adsorption devices comprising acid gas adsorption materials; and a fluid supply line for distributing and supplying the fluid to the plurality of acid gas adsorption devices, respectively; The fluid supply line includes: a branch portion; and a plurality of flow dividers, the plurality of flow dividers connecting the branch portion and the plurality of acid gas adsorbing devices, respectively. The plurality of flow dividing portions are respectively provided with resistance bodies.

2. The acid gas recovery system according to claim 1, wherein: The acid gas is carbon dioxide.

3. The acid gas recovery system according to claim 1 or 2, which can implement the following steps: an adsorption step in which a gas to be treated containing acid gas is supplied to the plurality of acid gas adsorption devices so that the acid gas is adsorbed on the acid gas adsorption material; and a desorption step in which the plurality of acid gas adsorption devices are heated so that the acid gas is desorbed from the acid gas adsorption material and the desorbed gas is supplied to the plurality of acid gas adsorption devices. In the desorption step, the flow path resistance of the resistor is larger than the flow path resistance of each of the plurality of acid gas adsorbing devices.

4. The acid gas recovery system according to claim 3, wherein: The resistance body can change the flow path resistance, In the adsorption step, the flow path resistance of the resistor is smaller than the flow path resistance of each of the plurality of acid gas adsorption devices.

5. The acid gas recovery system according to claim 4, wherein: The invention further includes a control unit capable of controlling the flow path resistance of the resistor.

6. The acid gas recovery system according to claim 3, wherein: The invention further comprises a detour line capable of bypassing the resistance body.

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