Gas concentration method and gas concentration apparatus

Abstract

This invention provides a novel gas concentration method that can reduce the amount of energy required. [Solution] The gas concentration method comprises: Step A, in which a flow 1 containing component A is brought into contact with an adsorbent to generate a flow 2 in which the partial pressure of component A is lower than that of flow 1; Step B, in which a flow 3 containing component B, which has a stronger adsorption effect on the adsorbent than component A, is brought into contact with the adsorbent after step A to cause the desorption of component A from the adsorbent due to the adsorption of component B to the adsorbent, thereby generating a flow 4 in which the partial pressure of component B is lower and the partial pressure of component A is higher than that of flow 3; and Step C, in which a flow 5 in which the partial pressures of components A and B are lower than that of flow 1, and the partial pressure of component B is lower than that of flow 3, is brought into contact with the adsorbent after step B to generate a flow 6 in which component B has been desorbed from the adsorbent. The partial pressure of component B in flow 3 in step B is three times or more the partial pressure of component A in flow 1 in step A, and 0.03 MPa (0.3 bar) or less.

Description

[Technical Field]

[0001] The present invention relates to a gas concentration method and a gas concentration apparatus. [Background technology]

[0002] Conventionally, methods for separating / concentrating a target gas from a mixed gas using the adsorption phenomenon are known. [Prior art documents] [Patent Documents]

[0003] [Patent Document 1] Japanese Patent Publication No. 2012-157812 [Patent Document 2] Japanese Patent Publication No. 2009-220004 [Patent Document 3] Japanese Patent Publication No. 2005-13898 [Patent Document 4] WO2021 / 117260A [Patent Document 5] Japanese Patent Publication No. 2019-13906 [Patent Document 6] US2023 / 0390693A [Overview of the project] [Problems that the invention aims to solve]

[0004] However, conventional technologies require the supply of large amounts of energy from external sources for thermal operations such as heating and cooling, and pressure operations such as pressurizing and depressurizing, making energy conservation a pressing need.

[0005] This invention has been made in view of the above-mentioned problems, and aims to provide a novel gas concentration method and gas concentration apparatus that can reduce the amount of energy required. [Means for solving the problem]

[0006] [1] Step A involves bringing a stream 1 containing component A into contact with an adsorbent to generate a stream 2 in which the partial pressure of component A is lower than that of stream 1. Step B involves bringing a flow 3 containing component B, which has a stronger adsorption capacity to the adsorbent than component A, into contact with the adsorbent that has gone through step A, thereby causing the desorption of component A from the adsorbent due to the adsorption of component B to the adsorbent, and generating a flow 4 in which the partial pressure of component B is lower and the partial pressure of component A is higher than that of flow 3. The process includes step C, in which the adsorbent having gone through step B is brought into contact with flow 5, in which the partial pressures of components A and B are lower than those of flow 1, and the partial pressure of component B is lower than that of flow 3, thereby generating flow 6 containing component B desorbed from the adsorbent. A gas concentration method in which the partial pressure of component B of flow 3 in step B is three times or more the partial pressure of component A of flow 1 in step A, and 0.03 MPa (0.3 bar) or less. [2] The method according to [1], wherein the flow 5 is the flow 2. [3] The method according to [1] or [2], wherein in step A, flow 1 further includes component B, and flow 2 is a flow in which the partial pressures of component A and component B are lower than those of flow 1. [4] Equipped with an adsorbent and a gas switching mechanism, The gas switching mechanism is State A: When a flow 1 containing component A is brought into contact with an adsorbent, a flow 2 is generated in which the partial pressure of component A is lower than that of flow 1. State B, in which the adsorbent has gone through state A is brought into contact with a flow 3 containing component B which has a stronger adsorption capacity to the adsorbent than component A, causing the adsorption of component B to the adsorbent and the desorption of component A from the adsorbent, thereby generating state B, in which the partial pressure of component B is lower and the partial pressure of component A is higher than that of flow 3, A gas concentrator that sequentially switches between states C, in which the adsorbent having gone through state B is brought into contact with a flow 5 in which the partial pressures of components A and B are lower than those of flow 1, and the partial pressure of component B is lower than that of flow 3, thereby generating a flow 6 containing component B that has been desorbed from the adsorbent, A gas concentrator in which the partial pressure of component B of flow 3 in state B is 0.03 MPa (0.3 bar) or less. [5] The gas switching mechanism is A honeycomb rotor containing the adsorbent, A first channel for supplying flow 1 to a first region of the honeycomb rotor and for discharging flow 2 from the first region, A second channel for supplying the flow 3 to the second region of the honeycomb rotor and for discharging the flow 4 from the second region, A third channel for supplying the flow 5 to the third region of the honeycomb rotor and for discharging the flow 6 from the third region, and The honeycomb rotor has a rotating means for rotating it around its axis, The first region, the second region, and the third region are fixed regions that are divided in the circumferential direction of the honeycomb rotor and do not rotate with the rotation of the honeycomb rotor. The gas concentration apparatus according to [4], wherein the adsorbent is moved in the order of the first region, the second region, and the third region as the honeycomb rotor rotates. [6] comprising a first adsorption tower, a second adsorption tower, and a third adsorption tower, each containing the adsorbent, The gas switching mechanism is State α, in which flow 1 is supplied to the first adsorption tower, flow 3 to the second adsorption tower, and flow 5 to the third adsorption tower. State β, in which flow 3 is supplied to the first adsorption tower, flow 5 to the second adsorption tower, and flow 1 to the third adsorption tower. A gas concentration apparatus according to [4] or [5], wherein state γ is sequentially switched on, supplying flow 5 to the first adsorption tower, flow 1 to the second adsorption tower, and flow 3 to the third adsorption tower. [7] The gas concentration apparatus according to [4] or [5], wherein the flow 5 is the flow 2. [8] The gas concentrator according to [4] or [5], wherein in state A, flow 1 further contains component B, and an adsorbent is generated by adsorbing component A and component B, and flow 2 is a flow in which the partial pressure of component A and component B is lower than that of flow 1. [Effects of the Invention]

[0007] According to the present invention, a novel gas concentration method and a gas concentration apparatus capable of reducing the required amount of energy are provided.

Brief Description of the Drawings

[0008] [Figure 1] FIG. 1 is a schematic perspective view of the gas concentration apparatus of the first embodiment. [Figure 2] FIG. 2 is a schematic diagram of the gas concentration apparatus of the second embodiment. [Figure 3] FIG. 3 is a graph showing the change over time in the composition of the exhaust gas when a gas containing N2O, CO2, H2O, and N2 is supplied to mordenite-type zeolite at a constant temperature.

Embodiments for Carrying Out the Invention

[0009] Embodiments of the present invention will be described with reference to the drawings. (Gas Concentration Method) The gas concentration method according to the present embodiment includes the following steps.

[0010] (Step A) A gas stream 1 containing component A is brought into contact with an adsorbent to generate a gas stream 2 having a lower partial pressure of component A than that of stream 1. By step A, component A is adsorbed on the adsorbent.

[0011] (Component A in Stream 1) There is no particular limitation on component A as long as it can be adsorbed by the adsorbent and can be desorbed from the adsorbent after adsorption. For example, CO, CO2, NO x , N2O, CH4, C2H6, C3H8, C4H 10 , C5H 12 , NH3, N2, O2, etc. may be used. Stream 1 may contain only one kind of component A, or may contain a plurality of kinds of component A. From the viewpoint of desorbing component A from the adsorbent in the subsequent step B after being adsorbed on the adsorbent, it is preferable that component A is physically adsorbed on the adsorbent.

[0012] (Partial Pressure of Component A in Stream 1) There are no particular limitations on the partial pressure of component A of flow 1 when in contact with the adsorbent; it is sufficient as long as the adsorbent can adsorb component A of flow 1 and generate flow 2, and it can be set appropriately depending on the combination of adsorbent and component A.

[0013] The partial pressures of each component A in a typical flow 1 may be 5 Pa or more, 10 Pa or more, 30,000 Pa or less, or 3,000 Pa or less.

[0014] (Other components of Flow 1: Component B) Flow 1 may contain components other than component A. Flow 1 may contain component B as defined in step B. Flow 1 may contain only one type of component B, or it may contain multiple types of component B.

[0015] Each partial pressure of component B of flow 1 may be 0 Pa or more, 5 Pa or more, 30,000 Pa or less, or 5,000 Pa or less. Each partial pressure of component B of flow 1 is preferably 10 times or less the partial pressure of component A, and more preferably 3 times or less.

[0016] (Other components of flow 1: component Z) Flow 1 may contain component Z, which has weaker adsorption properties to the adsorbent than component A, in step B described later. If flow 1 in step A contains component Z, the adsorbent can adsorb component Z in addition to component A. Flow 1 may contain only one type of component Z, or it may contain multiple types of component Z.

[0017] Each partial pressure of component Z of flow 1 may be 50 kPa or more, 70 kPa or more, 1000 kPa or less, or 110 kPa or less.

[0018] (Component A of flow 2) Flow 2 is a flow in which the partial pressure of component A is lower than that of flow 1. The individual partial pressures of component A in flow 2 may be 1 / 3 or less, 1 / 5 or less, 1 / 10 or less, or 1 / 20 or less of that of component A in flow 1.

[0019] The individual partial pressures of component A of a typical flow 2 may be 5 Pa or less, and may also be 1 Pa or less.

[0020] (Component B of flow 2) If flow 1 contains component B, then the partial pressures of component B in flow 2 will be lower than the partial pressures of component B in flow 1.

[0021] The individual partial pressures of component B in a typical flow 2 may be 5 Pa or less, and may also be 1 Pa or less.

[0022] (Component Z of flow 2) Each partial pressure of component Z in flow 2 may be the same as the partial pressure of component Z in flow 1, or it may be higher than the partial pressure of component Z in flow 1.

[0023] The partial pressures of each component Z of flow 2 may be 50 kPa or more, 70 kPa or more, 1000 kPa or less, or 110 kPa or less.

[0024] (Total pressure of flow 1 and flow 2) There are no particular limitations on the total pressure of flow 1 and flow 2. For example, the total pressure may be atmospheric pressure, higher than atmospheric pressure, or lower than atmospheric pressure. A typical range of total pressure may be 90 kPa or higher and 1000 kPa or lower.

[0025] (Adsorbent) In step A, the adsorbent only needs to be in a state where it can adsorb component A. For example, at least some or all of the adsorption sites of the adsorbent may be empty, and at least some or all of the adsorption sites may have component Z adsorbed on them, which has lower adsorption properties to the adsorbent than component A. In addition, some of the adsorption sites of the adsorbent may have component B adsorbed on them, which has stronger adsorption properties to the adsorbent than component A.

[0026] Specific examples of adsorbents will be discussed later.

[0027] (Temperature of the adsorbent in process A) There are no particular limitations on the temperature of the adsorbent at the time of contact with flow 1. It is sufficient to set the temperature within a range that allows the adsorbent to adsorb component A in flow 1 and generate flow 2 with a lower partial pressure of component A, and can be set appropriately depending on the combination of adsorbent and component A. Typical adsorbent temperatures may be 10°C or higher, 20°C or higher, 100°C or lower, or 80°C or lower.

[0028] In this process and in each of the processes of this embodiment, the temperature of the adsorbent may be controlled by directly heating or cooling the adsorbent, by heating or cooling the temperature of the gas in flow 1, or by heating or cooling both.

[0029] (B process) After obtaining the adsorbent in step A, step B is then performed.

[0030] In step B, a stream 3 containing component B (e.g., H2O), which has a stronger adsorption capacity to the adsorbent than component A (e.g., CO2, N2O), is brought into contact with the adsorbent that adsorbed component A in step A. This causes the adsorption of component B onto the adsorbent and the desorption of component A from the adsorbent. In other words, due to the difference in adsorption capacity, component A that was adsorbed on the adsorption site of the adsorbent is desorbed, and component B is adsorbed onto that site instead. This generates an adsorbent with component B adsorbed on it, and a stream 4 (e.g., a CO2, N2O concentrated stream) in which the partial pressure of component B is lower and the partial pressure of component A is higher than in stream 3.

[0031] Regarding the definition of component B, the adsorption properties of component A and component B to the adsorbent are defined by the product of the adsorption equilibrium constant of the Langmuir adsorption isotherm for a single gas of component A and the partial pressure of component A in flow 3, and the product of the adsorption equilibrium constant of the Langmuir adsorption isotherm for a single gas of component B and the partial pressure of component B in flow 3, respectively. The units of partial pressure are, for example, Pa and bar. The temperature at which the adsorption isotherm is determined is the temperature of the adsorbent in process B.

[0032] (Component B) In flow 3 of step B, there are no particular limitations on component B as long as the above-mentioned relationship between adsorption equilibrium constant and partial pressure is satisfied for component A. It is not limited as long as it can be adsorbed by the adsorbent and can be desorbed from the adsorbent after adsorption. Examples include H2O, CO, CO2, NO x , N2O, CH4, C2H6, C3H8, C4H 10 , C5H 12 It may be NH3, N2, O2, etc. Flow 3 may contain multiple components B for each component A. If flow 1 and / or flow 3 contain multiple components A, one or more components B are defined for each component A, but the same component B may be defined for multiple components A. Examples of combinations of component A and component B are as follows. They are expressed in the form component A:component B. Component A: Component B N2O:H2O N2O:CO2 N2O:H2O and CO2 CO2:H2O

[0033] (Partial pressure of component B of flow 3) The partial pressure of each component B in flow 3 is at least three times, preferably at least ten times, and more preferably at least fifty times, the partial pressure of the corresponding component A in flow 1. This makes it easier to make the partial pressure of component A in flow 4 higher than the partial pressure of component A in flow 1. Each partial pressure of component B in flow 3 may be 0.01 MPa (0.1 bar) or greater. The partial pressures of each component B in flow 3 are 0.03 MPa (0.3 bar) or less. Each partial pressure of component B in flow 3 may be greater than or equal to each partial pressure of component B in flow 1, or less than or equal to each partial pressure of component B in flow 1. Each partial pressure of component B in flow 3 may be more than twice, more than three times, or more than five times the individual partial pressures of component B in flow 1. If component B is H2O, flow 3 may be a flow containing saturated water vapor, for example, saturated moist air.

[0034] (Other components of Flow 3: Component A) Flow 3 may contain components other than component B. For example, flow 3 may contain component A as described above. Flow 3 may contain only one type of component A, or it may contain multiple types of component A. Preferably, the partial pressure of component A in flow 3 is less than or equal to the partial pressure of component A in flow 1, and is less than the partial pressure of component A in flow 1. From the viewpoint of promoting the desorption of component A adsorbed on the adsorbent and the subsequent adsorption of component B onto the adsorbent, preferably, the partial pressure of component A in flow 3 is 1 / 3 or less of the partial pressure of component A in flow 1, more preferably 1 / 5 or less, even more preferably 1 / 10 or less, and even more preferably 1 / 20 or less. Preferably, it is 1 / 3 or less of the sum of the partial pressures of the corresponding components B in flow 3, even more preferably 1 / 10 or less, and even more preferably 1 / 50 or less.

[0035] The partial pressures of component A of a typical flow 3 may be 0 Pa or greater, 5 Pa or greater, 30,000 Pa or less, or 1,000 Pa or less.

[0036] (Other components of Flow 3: Component Z) Flow 3 may contain component Z, which has weaker adsorption properties to the adsorbent than component A, in step B.

[0037] Regarding the definition of component Z, in process B, the adsorption capacity of component Z to the adsorbent is weaker than that of component A if the Langmuir adsorption isotherms for each single gas of component Z and component B are determined relative to the adsorbent, and the adsorption equilibrium constant of component Z is smaller than that of component A. Typically, the ratio of the equilibrium constants (adsorption equilibrium constant of component A / adsorption equilibrium constant of component Z) may be 50 times or more. The temperature used to determine the adsorption isotherm is the temperature of the adsorbent in process B.

[0038] Component Z is not limited as long as it is adsorbable to the adsorbent and can be detached from the adsorbent after adsorption. Furthermore, component Z may be a component that does not adsorb to the adsorbent. There are no particular limitations on the partial pressure of component Z in flow 3. Examples of component Z are N2, O 2、Examples include H2, He, Ne, Ar, Kr, etc. Even if flow 3 contains component Z, which has weaker adsorption properties to the adsorbent than component A in step B, it does not particularly change the manner of adsorption. Flow 3 may contain only one type of component Z, or it may contain multiple types of component Z.

[0039] The partial pressures of each component Z of a typical flow 3 may be 50 kPa or more, 70 kPa or more, 1000 kPa or less, or 800 kPa or less.

[0040] (Components A and B of flow 4) Flow 4 is a flow in which the partial pressures of each component B are lower and the partial pressures of each component A are higher than in Flow 3.

[0041] Each partial pressure of component B of flow 4 may be 1 / 3 or less, 1 / 5 or less, 1 / 10 or less, or 1 / 20 or less of each partial pressure of component B of flow 1.

[0042] The individual partial pressures of component B in a typical flow 4 may be 1 Pa or greater, and may also be 10 Pa or greater.

[0043] Each partial pressure of component A in flow 4 can be higher than each partial pressure of component A in flow 1. Each partial pressure of component A in flow 4 may be 10 Pa or more, and may be 100 Pa or more.

[0044] (Component Z of flow 4) Each partial pressure of component Z in flow 4 may be the same as each partial pressure of component Z in flow 3, and may be lower or higher than each partial pressure of component Z in flow 1.

[0045] Each partial pressure of component Z of flow 4 may be 50 kPa or more, 70 kPa or more, 1000 kPa or less, or 800 kPa or less.

[0046] (Total pressure of flow 3 and flow 4) There are no particular limitations on the total pressure of flows 3 and 4; it may be atmospheric pressure, higher than atmospheric pressure, or lower than atmospheric pressure. A typical range of total pressure is 90 kPa or higher and 1000 kPa or lower.

[0047] The total pressure of flow 3 and flow 4 may be the same as the total pressure of flow 1 and flow 2, that is, the pressure difference may be within ±10% or within ±5%.

[0048] (Temperature of the adsorbent) There are no particular limitations on the temperature of the adsorbent at the time of contact with flow 3. It is sufficient to set the temperature within a range that allows adsorption of component B of flow 3 to generate flow 4, and can be set appropriately depending on the combination of adsorbent and component B. When component B is water, from the viewpoint of keeping the partial pressure of component B at 0.03 MPa or less, the typical temperature of the adsorbent is preferably 69°C or lower, preferably 60°C or lower, may be 55°C or lower, or may be 50°C or lower.

[0049] The temperature of the adsorbent in step A and the temperature of the adsorbent in step B may be the same, for example, the temperature difference may be within 10°C or 5°C, or they may be different.

[0050] (C process) Step C is performed on the adsorbent obtained from Step B. In Step C, the adsorbent that has adsorbed component B is brought into contact with Flow 5, in which the partial pressures of component A (CO2, N2O, etc.) and component B (H2O, etc.) are lower than in Flow 1, and the partial pressure of component B (H2O, etc.) is lower than in Flow 3, to generate Flow 6 containing component B (H2O, etc.) desorbed from the adsorbent. Step C is an adsorbent regeneration step, in which component B is desorbed from the adsorbent, making it possible to adsorb component A again in Step A. In Step C, component B is desorbed from the adsorbent that has gone through Step B, and an adsorbent from which component B has been desorbed is generated.

[0051] (Component B of flow 5) From the viewpoint of desorbing component B from the adsorbent that has adsorbed component B obtained in step B, the partial pressures of component B in flow 5 are lower than the partial pressures of component B in flow 3 of step B.

[0052] From the viewpoint of efficiently adsorbing component A of flow 1 again in process A, the partial pressures of component B in flow 5 are lower than the partial pressures of component B in flow 1.

[0053] Each partial pressure of component B of flow 5 should be less than 0.03 MPa (0.3 bar), preferably 0.01 MPa (0.1 Bar) or less, more preferably 0.005 MPa (0.05 Bar) or less, may be 0.002 MPa (0.02 bar) or less, may be 0.001 MPa (0.01 bar) or less, may be 0.0005 MPa (0.005 bar) or less, may be 0.0002 MPa (0.002 bar) or less, and may be 0.0001 MPa (0.001 bar) or less.

[0054] (Component A of flow 5) From the viewpoint of efficiently adsorbing component A of flow 1 again in step A, the partial pressure of component A in flow 5 is lower than the partial pressure of component A in flow 1. If flow 3 contains component A, it is preferable that the partial pressure of component A in flow 5 is lower than the partial pressure of component A in flow 3.

[0055] The partial pressure of component A of flow 5 is preferably less than 0.03 MPa (0.3 bar), preferably 0.01 MPa (0.1 bar) or less, more preferably 0.005 MPa (0.05 bar) or less, may be 0.002 MPa (0.02 bar) or less, may be 0.001 MPa (0.01 bar) or less, may be 0.0005 MPa (0.005 bar) or less, may be 0.0002 MPa (0.002 bar) or less, and may be 0.0001 MPa (0.001 bar) or less.

[0056] (Other components of Flow 5: Component Z) Flow 5 does not necessarily contain components A and B. It is preferable that flow 5 has component Z as its main component. Flow 5 may contain only one type of component Z, or it may contain multiple types of component Z.

[0057] The partial pressures of each component Z of a typical flow 5 may be 90 kPa or more, 95 kPa or more, 1000 kPa or less, or 110 kPa or less.

[0058] (Combination of gas species of component A, component B, and component C) The following are examples of gas species combinations of components A, B, and C used throughout processes A to C. These are described below in the form of component A:component B:component Z. Component A: Component B: Component Z N2O:H2O:N2 N2O:CO2:N2 N2O:H2O and CO2:N2 CO2:H2O:N2

[0059] (Specific example of flow 5) Flow 5 may also be Flow 2.

[0060] (Components A and B of flow 6) Flow 6 contains component B, which has been detached from the adsorbent. The individual partial pressures of component B in flow 6 can be higher than the individual partial pressures of component B in flow 5.

[0061] The individual partial pressures of component B in a typical flow 6 may be 300 Pa or more, and may also be 3000 Pa or more.

[0062] (Component Z of flow 6) The principal component of flow 6 may be component Z, just like in flow 5.

[0063] Each partial pressure of component Z of flow 6 may be 85 kPa or more, 90 kPa or more, 1000 kPa or less, or 110 kPa or less.

[0064] (Total pressure of flow 5 and flow 6) There are no particular limitations on the total pressure of flows 5 and 6; it may be atmospheric pressure, higher than atmospheric pressure, or lower than atmospheric pressure. It may also be the same as the total pressure of flows 1 and 2, and the typical range of total pressure may be 90 kPa or higher and 1000 kPa or lower.

[0065] The total pressure of flow 6 may be lower than the total pressure of flow 5, may be 50 kPa or less, or 10 kPa or less.

[0066] (Temperature of the adsorbent) There are no particular limitations on the temperature of the adsorbent at the time of contact with flow 5. It is acceptable as long as it is within a range that can desorb component B of flow 5 and generate flow 6, and can be set appropriately depending on the combination of adsorbent and component B. Suitable adsorbent temperatures may be 0°C or higher, 10°C or higher, 100°C or lower, or 80°C or lower.

[0067] (State of the adsorbent) The adsorbent obtained in step C only needs to have adsorption sites that do not adsorb components B and A, and these adsorption sites that do not adsorb components B and A may be empty or may adsorb component Z.

[0068] (Effects and Benefits) According to the invention of this embodiment, in step B, component A adsorbed on the adsorbent is pushed out by the adsorption of component B, so that the concentration (partial pressure) of component A in flow 4 can be made higher than the concentration (partial pressure) of component A in flow 1. By repeating steps A to C after step C, it becomes possible to concentrate component A in flow 1 by repeatedly using the adsorbent. In the process of recovering component A, pressurizing, depressurizing, heating, and cooling of the flow and adsorbent are unnecessary.

[0069] (Adsorbent) There are no particular limitations on the adsorbent that can be used in the above embodiments. Any adsorbent that changes the amount of each gas component adsorbed at its adsorption site depending on the difference in the partial pressure of each gas component in the flow is acceptable. From this viewpoint, it is preferable to use an adsorbent that can reversibly adsorb each component, and such adsorption is sometimes called physical adsorption. Examples of adsorbents include activated carbon, zeolite, silica gel, activated alumina, mesoporous silica, porous coordination polymer, or metal-organic framework.

[0070] Examples of activated carbon include general activated carbon produced by methods such as steam activation, gas activation, alkali activation, and chemical activation, as well as high-performance activated carbon such as molecular sieve activated carbon, high surface area activated carbon, impregnated activated carbon, and biological activated carbon.

[0071] Zeolites are a general term for crystalline porous aluminosilicates. Zeolites are broadly classified according to the geometric structure (topology) of their skeleton. Examples of zeolites (classified by structural code in parentheses) include type A (LTA), faujasite (FAU) such as LSX, X, and Y types, L type (LTA), mordenite (MOR), ferrielite (FER), ZSM-5 (MFI), β type (BEA), and MCM-22 (MWW). Examples of MOR include synthetic mordenite containing Na as a cation species. Other types of MOR may be naturally occurring.

[0072] Examples of silica gel include Type A silica gel, which excels at absorbing moisture in low humidity conditions, and Type B silica gel, which excels at absorbing moisture in high humidity conditions.

[0073] Examples of porous coordination polymers or metal-organic frameworks include copper fumarate, copper terephthalate, and copper cyclohexanedicarboxylate.

[0074] Next, I will explain the gas concentration device.

[0075] (First Embodiment) Figure 1 illustrates the gas concentration apparatus 100 of the first embodiment. The gas concentration device 100 shown in Figure 1 comprises an adsorbent 10 and a gas switching mechanism 50.

[0076] The gas switching mechanism 50 includes a honeycomb rotor 52, a rotating means 54, a first flow path F1, a second flow path F2, and a third flow path F3.

[0077] The honeycomb rotor 52 has a cylindrical shape and a honeycomb wall (not shown) that forms numerous flow channels along the axial direction inside the cylinder. The flow channels formed by the honeycomb wall are filled with an adsorbent.

[0078] The rotating means 54 is a means for rotating the honeycomb rotor 52 around its axis. A specific example of the rotating means 54 is a motor fixed to the axis of the honeycomb rotor 52.

[0079] The honeycomb rotor 52 has three regions divided in the circumferential direction: a first region Z1, a second region Z2, and a third region Z3. The first region Z1, the second region Z2, and the third region Z3 are fixed regions that do not rotate with the rotation of the honeycomb rotor 52.

[0080] As the honeycomb rotor 52 rotates due to the rotating means 54, each adsorbent 10 moves in the order of first region Z1, second region Z2, third region Z3, and then returns to the first region Z1 again.

[0081] In the first region Z1, step A of the above method is performed. In the second region Z2, step B of the above method is performed. In the third region Z3, step C of the above method is performed.

[0082] There are no particular limitations on the sizes of the first region Z1, the second region Z2, and the third region Z3, but it is preferable that the volume of the third region Z3 > the volume of the first region Z1, and it is preferable that the volume of the third region Z3 > the volume of the second region Z2.

[0083] The first flow path F1 is a flow path that supplies flow 1 to a fixed first region Z1 and discharges flow 2 from the first region Z1. The second flow path F2 is a flow path that supplies flow 3 to a fixed second region Z2 and discharges flow 4 from the second region Z2. The third flow path F3 is a flow path that supplies flow 5 to a fixed third region Z3 and discharges flow 6 from the third region Z3.

[0084] In this embodiment, a fourth channel F4 is provided that connects the second channel F2 and the third channel F3.

[0085] According to this embodiment, the gas switching mechanism 50 brings a flow 1 containing component A (CO2, N2O, etc.) into contact with the adsorbent via the first flow path F1, generating a flow 2 in which the partial pressure of component A is lower than that of flow 1. (State A (Step A)) In state B (step B), the adsorbent that has gone through state A is brought into contact with flow 3 containing component B (H2O, etc.), which has a stronger adsorption effect on the adsorbent than component A (CO2, N2O, etc.), via the second flow path F2. This causes the adsorption of component B onto the adsorbent and the desorption of component A from the adsorbent, generating state B (step B), in which the partial pressure of component B is lower and the partial pressure of component A is higher than in flow 3. The adsorbent, having gone through state B, is brought into contact with a flow 5 via a third channel F3, where the partial pressures of component A (CO2, N2O, etc.) and component B (H2O, etc.) are lower than those of flow 1, and the partial pressure of component B (H2O, etc.) is lower than that of flow 3, thereby generating state C (step C) in which flow 6 containing component B (H2O, etc.) desorbed from the adsorbent.

[0086] Here, the partial pressure of component B in state B (process B) is three times or more the partial pressure of component A in flow 1 of state A (process A), and 0.03 MPa (0.3 bar) or less.

[0087] This allows component A in flow 1 to be concentrated in flow 4, and the adsorbent is regenerated by switching its state in the order of first region Z1, second region Z2, and third region Z3, and by repeating the switching, component A can be continuously concentrated.

[0088] In particular, using flow 2 as flow 5 improves process efficiency.

[0089] (Second embodiment) Next, a gas concentration apparatus 200 according to the second embodiment will be described with reference to Figure 2.

[0090] The gas concentration apparatus 200 includes a first adsorption tower 70A, a second adsorption tower 70B, a third adsorption tower 70C, and a gas switching mechanism 40.

[0091] The first adsorption tower 70A, the second adsorption tower 70B, and the third adsorption tower 70C each contain an adsorbent inside.

[0092] The gas switching mechanism 40 includes a line F1A that supplies flow 1 to one end of the first adsorption tower 70A, a line F1B that supplies flow 1 to one end of the second adsorption tower 70B, and a line F1C that supplies flow 1 to one end of the third adsorption tower 70C. Line F1A has a valve V1A, line F1B has a valve V1B, and line F1C has a valve V1C.

[0093] The gas switching mechanism 40 further includes a three-way branch line F2Z. The three-way branch line F2Z includes a first line F2A connecting branch point B to the other end of the first adsorption tower 70A, a second line F2B connecting branch point B to the other end of the second adsorption tower 70B, and a third line F2C connecting branch point B to the other end of the third adsorption tower 70C.

[0094] The first line F2A has valve V2A, the second line F2B has valve V2B, and the third line F2C has valve V2C.

[0095] The three-way branch line F2Z is ​​the line through which flow 2 discharged from the first adsorption tower 70A, the second adsorption tower 70B, and the third adsorption tower 70C, and flow 5 supplied to them, pass.

[0096] The gas switching mechanism 40 includes line F3A which supplies flow 3 to the other end of the first adsorption tower 70A, line F3B which supplies flow 3 to the other end of the second adsorption tower 70B, and line F3C which supplies flow 3 to the other end of the third adsorption tower 70C. Line F3A has valve V3A, line F3B has valve V3B, and line F3C has valve V3C in that order.

[0097] The gas switching mechanism 40 includes a line F4A that discharges flow 4 from one end of the first adsorption tower 70A, a line F4B that discharges flow 4 from one end of the second adsorption tower 70B, and a line F4C that discharges flow 4 from one end of the third adsorption tower 70C. Line F4A has a valve V4A, line F4B has a valve V4B, and line F4C has a valve V4C.

[0098] The gas switching mechanism 40 includes a line F6A that discharges flow 6 from one end of the first adsorption tower 70A, a line F6B that discharges flow 6 from one end of the second adsorption tower 70B, and a line F6C that discharges flow 6 from one end of the third adsorption tower 70C. Line F6A has a valve V6A, line F6B has a valve V6B, and line F6C has a valve V6C.

[0099] Next, I will explain how this adsorption device works. The gas switching mechanism 40 of this gas adsorption device is State α, where flow 1 is supplied to the first adsorption tower 70A, flow 3 to the second adsorption tower 70B, and flow 5 to the third adsorption tower 70C. State β, where flow 3 is supplied to the first adsorption tower 70A, flow 5 to the second adsorption tower 70B, and flow 1 to the third adsorption tower 70C. The system sequentially switches between states γ, supplying flow 5 to the first adsorption tower 70A, flow 1 to the second adsorption tower 70B, and flow 3 to the third adsorption tower 70C. After state γ, the cycle from state α to state γ is repeated.

[0100] In state α, valves V1A, V2A, V2C, V6C, V3B, and V4B are open, while the other valves V1B, V1C, V2B, V3A, V3C, V4A, V4C, V6A, and V6B are closed.

[0101] In state α, state A (step A) is performed, in which flow 1 containing component A (CO2, N2O, etc.) is brought into contact with the adsorbent in the first adsorption tower 70A to generate flow 2 in which the partial pressure of component A is lower than that of flow 1. In the second adsorption tower 70B, a flow 3 containing component B (H2O, etc.), which has a stronger adsorption capacity to the adsorbent than component A (CO2, N2O, etc.), is brought into contact with the adsorbent that has adsorbed component A in the previous state. This causes the desorption of component A from the adsorbent due to the adsorption of component B to the adsorbent, and a state B (step B) is performed in which a flow 4 (CO2, N2O concentrated flow) is generated in which the partial pressure of component B is lower and the partial pressure of component A is higher than that of flow 3. In the third adsorption tower 70C, a flow 5 is brought into contact with the adsorbent containing component B, where the partial pressures of component A (CO2, N2O, etc.) and component B (H2O, etc.) are lower than in flow 1, and the partial pressure of component B (H2O, etc.) is lower than in flow 3. This process generates a flow 6 containing component B (H2O, etc.) desorbed from the adsorbent. This is called state C (step C).

[0102] In state β, valves V1C, V2C, V2B, V6B, V3A, and V4A are open, while the other valves V1A, V1B, V2A, V3B, V3C, V4B, V4C, V6A, and V6C are closed.

[0103] In state β, state A (A process) is performed in which component A in flow 1 is adsorbed onto the adsorbent in the third adsorption tower 70C from which component B has been desorbed. State B (B process) is performed in which component A is desorbed from the adsorbent in the first adsorption tower 70A from which component A has been adsorbed by the adsorption of component B. State C (C process) is performed in which component B is desorbed from the adsorbent in the second adsorption tower 70B from which component B has been adsorbed by flow 5.

[0104] In state γ, valves V1B, V2A, V2B, V6A, V3C, and V4C are open, while the other valves V1A, V1C, V2C, V3A, V3B, V4A, V4B, V6B, and V6C are closed.

[0105] In state γ, state A (A step) is performed in which component A in flow 1 is adsorbed onto the adsorbent in the second adsorption tower 70B from which component B has been desorbed. State B (B step) is performed in which component A is desorbed from the adsorbent in the third adsorption tower 70C from which component A has been adsorbed by the adsorption of component B. State C (C step) is performed in which component B is desorbed from the adsorbent in the first adsorption tower 70A from which component B has been adsorbed by flow 5.

[0106] Similar to the first embodiment, the partial pressure of component B in state B (step B) is three times or more the partial pressure of component A in flow 1 of state A (step A), and 0.03 MPa (0.3 bar) or less.

[0107] In state B (process B), gas with a high concentration of component A is often discharged as flow 4, especially in the initial stages. By collecting only the initial gas of flow 4 in each state, the concentration efficiency can be increased.

[0108] In state C (process C), the desorption of component B may be promoted by reducing the pressure in the adsorption tower and the downstream lines F6A, B, and C. In this case, the pressure difference between the upstream and downstream sides of the valves V2A, B, and C in the upstream line can be adjusted by adjusting the opening of these valves.

[0109] In state C (step C), the desorption of component B may be promoted by heating the adsorption tower. Alternatively, the heated flow 5 may be supplied to the adsorption tower by heating line F2Z.

[0110] In this embodiment as well, the above method can be suitably carried out by switching between states A to C for each adsorption tower.

[0111] In this specification, the gas concentration apparatus is not limited to the above-described embodiments, and various modified embodiments are possible.

[0112] For example, in the gas concentration apparatus shown in Figure 1, it is also possible to implement the apparatus without a fourth flow path F4, using a flow other than flow 2 as flow 5.

[0113] Furthermore, in the gas concentration apparatus shown in Figure 2, the piping in the gas switching mechanism 40 can also be configured in other ways as appropriate.

[0114] For example, instead of the three-way branch line F2Z in Figure 2, there may be a line connecting the first adsorption tower 70A and the second adsorption tower 70B and having a valve, a line connecting the first adsorption tower 70A and the third adsorption tower 70C and having a valve, and a line connecting the second adsorption tower 70B and the third adsorption tower 70C and having a valve.

[0115] Furthermore, the configuration of the flow paths is flexible, and in Figure 2, it is possible to implement the system even if flow 3 is supplied to the adsorption tower from the same side as flow 1 and flow 4 is discharged from the same side as flow 2.

[0116] Next, regarding the above embodiment, an example of a suitable adsorbent combination with components A, B, and C, and an example of its adsorption behavior are shown.

[0117] Adsorbent: Natural mordenite-type zeolite (manufactured by Shin-Tohoku Chemical Industry Co., Ltd.) Volume ratio of each component of the supply gas: N2O: 250 ppm, CO2: 3000 ppm, H2O: 22000 ppm, balance gas is dry N2O The above-mentioned gas was supplied to a column packed with the above-mentioned adsorbent under atmospheric pressure at 25°C, and the time-dependent changes in the concentrations of N2O, CO2, and H2O in the exhaust gas composition were measured using GC-ECD, GC-TCD, and a dew point meter, respectively.

[0118] The results are shown in Fig. 3 and Table 1. The vertical axis C / C0 in Fig. 3 is the ratio of the actually measured gas concentration to the Inlet value (C0). Also, the average values of the gas concentrations in the respective intervals A, B1, B2, and C described in Fig. 3 are recorded as the gas volume ratios (ppm) in Table 1.

Table 1

[0119] Regarding the definition of component B, the adsorbabilities of components A and B to the adsorbent are defined by the product of the respective partial pressures in the feed gas and the Langmuir adsorption equilibrium constant obtained from the single-component gas equilibrium adsorption isotherm. The Langmuir adsorption isotherm is expressed as follows:

Equation

[0120] In this system, N2 corresponds to component Z. The adsorption equilibrium constant of N2 to the adsorbent is 0.61 bar -1 and is sufficiently smaller than the adsorption equilibrium constants of N2O, CO2, and H2O.

[0121] In process (A) in Figure 3, N2O and CO2 are adsorbed onto the adsorbent as component A. In process (A), in addition to the adsorption of N2O and CO2, the adsorption of H2O also occurs in parallel. Process (A) continues until the adsorption sites are occupied by N2O, CO2, and H2O.

[0122] In process (B1), H2O is adsorbed onto the adsorbent in exchange for the adsorbed N2O, resulting in a gas stream concentrated with N2O.

[0123] In process (B2), H2O is adsorbed onto the adsorbent in exchange for the adsorbed CO2, resulting in a gas in which CO2 is concentrated.

[0124] Subsequently, when the adsorption sites of the adsorbent are occupied by H2O, a breakthrough state occurs, as in process (C), and the composition of the exhaust gas becomes the same as that of the supply gas.

[0125] From the above, it can be understood that the gas concentration method according to this embodiment can be implemented. The process in Figure 3(A) corresponds to process A, and Figures 3(B1) and (B2) correspond to process B. [Industrial applicability]

[0126] According to the gas concentration method and apparatus of this embodiment, gases with low partial pressure can be efficiently concentrated, making them effective in reducing trace components in various types of exhaust gases. [Explanation of symbols]

[0127] 10...Adsorbent, 40, 50...Gas switching mechanism, 52...Honeycomb rotor, 54...Rotating means, 100, 200...Gas concentrator, 70A...First adsorption tower, 70B...Second adsorption tower, 70C...Third adsorption tower, V1A, V1B, V1C, V2A, V2B, V2C, V3A, V3B, V3C, V4A, V4B, V4C, V6A, V6B, V6C...Valves, F1...First flow path, F2...Second flow path, F3...Third flow path, Z1...First region, Z2...Second region, Z3...Third region.

Claims

1. Step A involves bringing a stream 1 containing component A into contact with an adsorbent to generate a stream 2 in which the partial pressure of component A is lower than that of stream 1. Step B involves bringing a flow 3 containing component B, which has a stronger adsorption capacity to the adsorbent than component A, into contact with the adsorbent that has gone through step A, thereby causing the desorption of component A from the adsorbent due to the adsorption of component B to the adsorbent, and generating a flow 4 in which the partial pressure of component B is lower and the partial pressure of component A is higher than that of flow 3. The process includes step C, in which the adsorbent having gone through step B is brought into contact with a flow 5 in which the partial pressures of components A and B are lower than those of flow 1, and the partial pressure of component B is lower than that of flow 3, thereby generating a flow 6 containing component B desorbed from the adsorbent. A gas concentration method in which the partial pressure of component B of flow 3 in step B is three times or more the partial pressure of component A of flow 1 in step A, and 0.03 MPa (0.3 bar) or less.

2. The method according to claim 1, wherein the flow 5 is the flow 2.

3. The method according to claim 1 or 2, wherein in step A, flow 1 further includes component B, and flow 2 is a flow in which the partial pressures of component A and component B are lower than those of flow 1.

4. It is equipped with an adsorbent and a gas switching mechanism. The gas switching mechanism is State A: A flow 1 containing component A is brought into contact with an adsorbent to generate a flow 2 in which the partial pressure of component A is lower than that of flow 1. State B is created when a flow 3 containing component B, which has a stronger adsorption capacity to the adsorbent than component A, is brought into contact with the adsorbent that has gone through state A, causing the adsorption of component B to the adsorbent and the desorption of component A from the adsorbent, thereby generating state B, in which the partial pressure of component B is lower and the partial pressure of component A is higher than that of flow 3. A gas concentrator that sequentially switches between states C, in which the adsorbent having gone through state B is brought into contact with a flow 5 in which the partial pressures of components A and B are lower than those of flow 1, and the partial pressure of component B is lower than that of flow 3, thereby generating a flow 6 containing component B that has been desorbed from the adsorbent, A gas concentrator in which the partial pressure of component B of the flow 3 in state B is 0.03 MPa (0.3 bar) or less.

5. The gas switching mechanism is A honeycomb rotor containing the adsorbent, A first channel for supplying flow 1 to a first region of the honeycomb rotor and for discharging flow 2 from the first region, A second channel for supplying the flow 3 to the second region of the honeycomb rotor and for discharging the flow 4 from the second region, A third flow path supplies the flow 5 to the third region of the honeycomb rotor and discharges the flow 6 from the third region, and The honeycomb rotor has a rotating means for rotating it around its axis, The first region, the second region, and the third region are fixed regions that are divided in the circumferential direction of the honeycomb rotor and do not rotate with the rotation of the honeycomb rotor. The gas concentration apparatus according to claim 4, wherein the adsorbent is moved in the order of the first region, the second region, and the third region as the honeycomb rotor rotates.

6. The system comprises a first adsorption tower, a second adsorption tower, and a third adsorption tower, each containing the adsorbent, The gas switching mechanism is State α, in which flow 1 is supplied to the first adsorption tower, flow 3 to the second adsorption tower, and flow 5 to the third adsorption tower. State β, in which flow 3 is supplied to the first adsorption tower, flow 5 to the second adsorption tower, and flow 1 to the third adsorption tower. The gas concentration apparatus according to claim 4 or 5, wherein state γ is sequentially switched, in which flow 5 is supplied to the first adsorption tower, flow 1 to the second adsorption tower, and flow 3 to the third adsorption tower.

7. The gas concentration apparatus according to claim 4 or 5, wherein the flow 5 is the flow 2.

8. The gas concentration apparatus according to claim 4 or 5, wherein in state A, flow 1 further contains component B, generating an adsorbent that adsorbs component A and component B, and flow 2 is a flow in which the partial pressure of component A and component B is lower than that of flow 1.

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