Gas separation method

Abstract

The purpose of the present disclosure is to provide a novel separation method for separating refrigerant gas.　This gas separation method comprises: a first step in which a raw material gas containing at least a refrigerant gas A and a refrigerant gas B is supplied to a first module to obtain a first separation gas and a first holding gas that differ in composition from the raw material gas; and a second step in which the first separation gas is supplied to a second module to obtain a second separation gas and a second holding gas that differ in composition from the first separation gas. The first module and / or the second module includes a molecular sieve membrane.

Description

Gas separation method

[0001] This disclosure relates to a gas separation method.

[0002] A known method for separating fluorocarbons involves distilling a mixture of fluorocarbons. Patent Document 1 describes a method in which a mixture containing 2,3,3,3-tetrafluoropropene and hexafluoropropene is mixed with an extraction solvent to obtain an extraction mixture, and then this extraction mixture is distilled to obtain a distillate mainly composed of hexafluoropropene and a distillate containing 2,3,3,3-tetrafluoropropene.

[0003] Japanese Patent Publication No. 2018-002602

[0004] This disclosure aims to provide a novel separation method for separating refrigerant gases.

[0005] This disclosure includes the following embodiments: [1] A gas separation method comprising: a first step of supplying a raw material gas containing at least refrigerant gas A and refrigerant gas B to a first module to obtain a first separation gas and a first retention gas having a different composition from the raw material gas; and a second step of supplying the first separation gas to a second module to obtain a second separation gas and a second retention gas having a different composition from the first separation gas, wherein at least one of the first module and the second module is equipped with a molecular sieve membrane. [2] The gas separation method according to [1], wherein the first module and the second module are connected in series or in parallel. [3] The gas separation method according to [1] or [2], wherein in the first step, the second retention gas is supplied to the first module together with the raw material gas. [4] The gas separation method according to any one of [1] to [3], wherein the molecular sieve membrane comprises one or more membranes selected from zeolite, silica, and organosilica. [5] The gas separation method according to any one of [1] to [4], wherein the molecular sieve membrane comprises a membrane of organosilica. [6] The gas separation method according to [5], wherein the organosilica comprises a unit represented by the following formula: -Si-X-Si- [wherein X represents a hydrocarbon group]. [7] The X is C ２－１２The gas separation method according to [6], which represents a hydrocarbon group. [8] The permeability of the refrigerant gas A through the molecular sieve membrane is 10 －９ mol / (m ２ ·s·Pa) or more, and the permeability of the refrigerant gas B through the molecular sieve membrane is 10 －１１ mol / (m ２ ·s·Pa) or more. The gas separation method according to any one of [1] to [7]. [9] The gas separation method according to any one of [1] to [8], wherein the pore diameter of the molecular sieve membrane is 2 Å or more and 10 Å or less.

[10] The nitrogen permeability Q Ｎ２ of the molecular sieve membrane, and the SF ６ permeability Q ＳＦ６ of the molecular sieve membrane, and the ratio Q Ｎ２ / Q ＳＦ６ is 100 or more. The gas separation method according to any one of [1] to [9].

[11] The gas separation method according to any one of [1] to

[10] , wherein the differential pressure between the gas supplied to the first module and the first separated gas is 100 kPa or more.

[12] The gas separation method according to any one of [1] to

[11] , wherein the first step and the second step are carried out at a temperature of 300 °C or less.

[13] The gas separation method according to any one of [3] to

[12] , further comprising boosting the pressure of the second holding gas before supplying the second holding gas to the first module.

[14] The refrigerant gas A contains C ｎ fluorocarbon, and the refrigerant gas B contains C ｎ＋ｍA gas separation method according to any one of [1] to

[13] , wherein the refrigerant gas contains a fluorocarbon, where n is an integer of 1 or more, and m is an integer of 1 or more.

[15] A gas separation method according to any one of [1] to

[14] , wherein the refrigerant gas contains R32 and the refrigerant gas B contains R125.

[16] A gas separation method according to any one of [1] to

[15] , wherein the content of the refrigerant gas A is 20% by mass or more with respect to the total amount of the raw material gas.

[17] A gas separation method according to any one of [1] to [6], wherein the content of the refrigerant gas A in the second separated gas is 50% by mass or more.

[18] A gas separation method according to any one of [1] to

[17] , wherein the content of the refrigerant gas A in the second separated gas is 70% by mass or more.

[19] A gas separation method according to any one of [1] to

[18] , wherein the content of the refrigerant gas A in the second separated gas is 90% by mass or more.

[20] A gas separation apparatus comprising: a first module for separating a raw material gas containing at least refrigerant gas A and refrigerant gas B into a first separation gas and a first retention gas having a different composition from the raw material gas; and a second module for separating the first separation gas into a second separation gas and a second retention gas having a different composition from the first separation gas, wherein at least one of the first module and the second module is equipped with a molecular sieve membrane.

[21] The gas separation apparatus according to

[20] , wherein the first module and the second module are connected in series or in parallel.

[22] The gas separation apparatus according to

[20] or

[21] , further comprising a first piping for recovering the second retention gas and supplying it to the raw material gas.

[23] The gas separation apparatus according to any one of

[20] to

[22] , wherein the molecular sieve membrane comprises one or more membranes selected from zeolite, silica, and organosilica.

[24] The gas separation apparatus according to any one of

[20] to

[23] , wherein the molecular sieve membrane comprises a membrane of organosilica.

[25] The gas separation apparatus according to

[24] , wherein the organosilica comprises a unit represented by the following formula: -Si-X-Si- [wherein X represents a hydrocarbon group].

[26] The X is C ２－１２ A gas separation apparatus according to

[25] , representing a hydrocarbon group.

[27] The permeability of the refrigerant gas A through the molecular sieve membrane is 10－９ mol / (m ２ The pressure is 10 s·Pa or higher, and the permeability of the refrigerant gas B through the molecular sieve membrane is 10 －１１ mol / (m ２ A gas separation apparatus according to any one of

[20] to

[26] , wherein the pressure is s・Pa) or higher.

[28] A gas separation apparatus according to any one of

[20] to

[27] , wherein the pore size of the molecular sieve membrane is 2 Å or more and 10 Å or less.

[29] The nitrogen permeability Q of the molecular sieve membrane. Ｎ２ and the SF of the molecular sieve membrane ６ Transparency Q ＳＦ６ The ratio of Q Ｎ２ / Q ＳＦ６ A gas separation apparatus according to any one of

[20] to

[28] , wherein the pressure difference between the gas supplied to the first module and the first separated gas is 100 kPa or more.

[30] A gas separation apparatus according to any one of

[20] to

[29] , wherein the temperature of the first module and the second module is 300°C or less.

[32] A gas separation apparatus according to any one of

[22] to

[31] , wherein the first piping has a booster device.

[33] The refrigerant gas A is C ｎ The refrigerant gas B contains fluorocarbons, and the refrigerant gas B is C ｎ＋ｍA gas separation apparatus according to any one of

[20] to

[32] , wherein the refrigerant gas contains a fluorocarbon, where n is an integer of 1 or more, and m is an integer of 1 or more.

[34] A gas separation apparatus according to any one of

[20] to

[33] , wherein the refrigerant gas contains R32 and the refrigerant gas B contains R125.

[35] A gas separation apparatus according to any one of

[20] to

[34] , wherein the content of the refrigerant gas A is 20% by mass or more with respect to the total amount of the raw material gas.

[36] A gas separation apparatus according to any one of

[20] to

[35] , wherein the content of the refrigerant gas A in the second separated gas is 50% by mass or more.

[37] A gas separation apparatus according to any one of

[20] to

[36] , wherein the content of the refrigerant gas A in the second separated gas is 70% by mass or more.

[38] The gas separation apparatus according to any one of

[20] to

[37] , wherein the content of refrigerant gas A in the second separated gas is 90% by mass or more.

[0006] This disclosure provides a novel separation method for separating refrigerant gases.

[0007] Figure 1 is a schematic diagram showing an example of the gas separation apparatus of this disclosure. Figure 2 is a schematic diagram showing an example of the gas separation apparatus of this disclosure. Figure 3 is a schematic diagram showing an example of the gas separation apparatus of this disclosure. Figure 4 is a schematic diagram showing an example of the gas separation apparatus of this disclosure. Figure 5 is a schematic diagram showing an example of the gas separation apparatus of this disclosure. Figure 6 is a schematic diagram showing an example of the gas separation apparatus of this disclosure.

[0008] (First Embodiment: Gas Separation Method) The gas separation method of the present disclosure includes: a first step of supplying a raw material gas containing at least refrigerant gas A and refrigerant gas B to a first module to obtain a first retaining gas and a first separation gas having a different composition from the raw material gas; and a second step of supplying the first separation gas to a second module to obtain a second retaining gas and a second separation gas having a different composition from the first separation gas, wherein at least one of the first module and the second module is equipped with a molecular sieve membrane.

[0009] The gas separation method of this disclosure can provide a method for separating new refrigerant gases. Preferably, the gas separation method of this disclosure can achieve higher separation efficiency.

[0010] In one embodiment, the refrigerant gas separated from the raw material gas may be refrigerant gas A.

[0011] In the first step, a raw material gas containing at least refrigerant gas A and refrigerant gas B is supplied to the first module to obtain a first separation gas and a first holding gas having different compositions from the raw material gas. In this disclosure, "different gas compositions" includes cases where the content ratios of two or more gases are different. Specifically, it is preferable that the content ratios of refrigerant gas A and refrigerant gas B in the raw material gas are different from the content ratios of refrigerant gas A and refrigerant gas B in the first separation gas and the first holding gas, respectively.

[0012] In this disclosure, “gas” includes substances that exist as a gas when subjected to the above method, and in a preferred embodiment, may include substances that exist as a gas at room temperature (25°C) and atmospheric pressure (1,013 hPa).

[0013] (Raw material gas) Refrigerant gas A and refrigerant gas B may be any gas used as a refrigerant, preferably containing one or more selected from fluorocarbon gas, ammonia, carbon dioxide, water, air, and hydrocarbons, and more preferably containing fluorocarbon gas. The fluorocarbon content in refrigerant gas A is preferably 80% by mass or more and 100% by mass or less, more preferably 90% by mass or more and 100% by mass or less, and even more preferably 95% by mass or more and 100% by mass or less. The fluorocarbon content in refrigerant gas B is preferably 80% by mass or more and 100% by mass or less, more preferably 90% by mass or more and 100% by mass or less, and even more preferably 95% by mass or more and 100% by mass or less.

[0014] The above-mentioned fluorocarbons are compounds containing carbon atoms and fluorine atoms bonded to those carbon atoms. Typical examples include hydrochlorofluorocarbons, hydrofluorocarbons, and hydrofluoroolefins.

[0015] Examples of the above-mentioned hydrochlorofluorocarbons include chlorodifluoromethane and chlorotrifluoroethane.

[0016] Examples of the above-mentioned hydrofluorocarbons include C1 hydrofluorocarbons such as difluoromethane; difluoroethane (e.g., 1,1-difluoroethane, 1,2-difluoroethane, especially 1,1-difluoroethane), trifluoroethane (e.g., 1,1,1-trifluoroethane, 1,1,2-trifluoroethane, especially 1,1,1-trifluoroethane), tetrafluoroethane (e.g., 1,1,1,2-tetrafluoroethane, 1,1,2,2-tetrafluoroethane, especially 1,1,1,2-tetrafluoroethane), pentafluoroethane, and other C2 hydrofluorocarbons; and C3 hydrofluorocarbons such as tetrafluoropropene and hexafluoropropene.

[0017] Examples of hydrofluoroolefins include 2,3,3,3-tetrafluoropropene (HFO-1234yf), 1,3,3,3-tetrafluoropropene (HFO-1234ze), cis-1,1,1,4,4,4-hexafluoro-2-butene (HFO-1336mzz-Z; DR-2), and trans-1,1,1,4,4,4-hexafluoro-2-butene (HFO-1336mzz-E).

[0018] The above fluorocarbon is preferably C １ Fluorocarbon and C ２ The gas contains fluorocarbons, more preferably difluoromethane and pentafluoroethane, and even more preferably consists of difluoromethane and pentafluoroethane. In another embodiment, the two or more fluorocarbon gases may contain a fluorocarbon having one carbon atom and a fluorocarbon having three carbon atoms, preferably containing difluoromethane (R32) and tetrafluoropropene (particularly 2,3,3,3-tetrafluoropropene, R1234yf), and more preferably consisting of difluoromethane (R32) and tetrafluoropropene (particularly 2,3,3,3-tetrafluoropropene, R1234yf).

[0019] The number of carbon atoms in the above-mentioned fluorocarbon is preferably 1 to 5, more preferably 1 to 3.

[0020] In one embodiment, refrigerant gas A is C ｎ Contains fluorocarbons, and refrigerant gas B is C ｎ＋ｍ It is preferable that it contains fluorocarbons. Here, n represents an integer of 1 or more, preferably 1 to 4, more preferably 1 to 2. m represents an integer of 1 or more, preferably 1 to 5, more preferably 1 to 3. C in refrigerant gas A ｎ The fluorocarbon content is preferably 80% by mass or more and 100% by mass or less, more preferably 90% by mass or more and 100% by mass or less, and even more preferably 95% by mass or more and 100% by mass or less. C in refrigerant gas A ｎ＋ｍ The fluorocarbon content is preferably 80% by mass or more and 100% by mass or less, more preferably 90% by mass or more and 100% by mass or less, and even more preferably 95% by mass or more and 100% by mass or less. In the above embodiment, refrigerant gas A is C ｎ＋ｍ It is preferable that it does not contain fluorocarbons. Also, refrigerant gas B is C ｎ It is preferable that the product does not contain fluorocarbons.

[0021] In a preferred embodiment, refrigerant gas A is C １ Contains fluorocarbons, and refrigerant gas B is C ２ It is preferable that the refrigerant gas A contains fluorocarbons, and more preferably that it contains R32 (difluoromethane) and R125 (pentafluoroethane).

[0022] In another preferred embodiment, refrigerant gas A is C １ Contains fluorocarbons, and refrigerant gas B is C ３ It is preferable that the mixture contains fluorocarbons, and it is preferable that refrigerant gas A contains R32 (difluoromethane) and refrigerant gas B contains tetrafluoropropene (particularly 2,3,3,3-tetrafluoropropene, R1234yf).

[0023] The molecular diameter of the source gas is preferably 2 Å or more and 10 Å or less, more preferably 3 Å or more and 8 Å or less.

[0024] In one embodiment, the molecular diameter of refrigerant gas A (the refrigerant to be separated) is preferably 2 Å or more and 7 Å or less, more preferably 3 Å or more and 5 Å or less, and even more preferably 3.2 Å or more and 4.4 Å or less. Alternatively, the molecular diameter of refrigerant gas A (the refrigerant to be separated) may be preferably 2 Å or more, more preferably 3 Å or more, even more preferably 3.2 Å or more, preferably 7 Å or less, more preferably 5 Å or less, and even more preferably 4.4 Å or less.

[0025] In the same embodiment, the molecular diameter of refrigerant gas B is, for example, greater than 4 Å, may be between 4.2 Å and 10 Å, or between 4.4 Å and 8 Å. Alternatively, the molecular diameter of refrigerant gas B may be, for example, greater than 4 Å, preferably 4.2 Å or more, and may be between 10 Å and 8 Å.

[0026] In the same embodiment, the difference in molecular diameter between refrigerant gas A and refrigerant gas B is preferably 0.1 Å or more, more preferably 0.2 Å to 3 Å, and even more preferably 0.3 Å to 2 Å.

[0027] The molecular diameter of the refrigerant in this disclosure may be a value calculated by the following formula, assuming that the shape of the refrigerant molecule is a rigid sphere: d = (ma / (3 × 2) １／２ ηπ)) １／２ …(x1) where, in equation (x1), d is the molecular diameter, m is the mass of a single molecule, a is the molecular velocity, and η is the viscosity coefficient. a is calculated by the following equation: a = (γRT / M) １／２ …(x2) Here, γ is the specific heat ratio and is approximated as 1.333. Also, R is the gas constant, T is the absolute temperature, and M is the molar molecular mass. Furthermore, η may be measured by the capillary method.

[0028] The boiling point of the above-mentioned raw material gas may be, for example, preferably -80°C to -20°C, more preferably -60°C to -30°C, and even more preferably -50°C to -30°C at 1 atmosphere. The difference in boiling points between refrigerant gas A and refrigerant gas B may be, for example, preferably 0°C to 20°C, and more preferably 0°C to 10°C at 1 atmosphere.

[0029] The above-mentioned raw material gas may be an azeotropic mixture or pseudo-azeotropic mixture of refrigerant gas A and refrigerant gas B. According to the gas separation method of this disclosure, even an azeotropic mixture or pseudo-azeotropic mixture can be used to separate a specific refrigerant gas. Examples of such azeotropic or pseudo-azeotropic mixtures include mixtures in which the difference between the boiling point of refrigerant gas A and the boiling point of refrigerant gas B is 1°C or more and 20°C or less, and further, 3°C or more and 18°C ​​or less.

[0030] Refrigerant gas A may contain one or more types of gas, and refrigerant gas B may contain one or more types of gas.

[0031] The content of refrigerant gas A is preferably 20% by mass or more, more preferably 30% by mass or more and 95% by mass or less, and even more preferably 40% by mass or more and 90% by mass or less, relative to the total amount of raw material gas.

[0032] The total content of refrigerant gas A and refrigerant gas B in the raw material gas is preferably 80% by mass or more and 100% by mass or less, more preferably 90% by mass or more and 100% by mass or less, and even more preferably 95% by mass or more and 100% by mass or less.

[0033] The raw material gas may contain refrigerant gases other than refrigerant gas A and refrigerant gas B. The total content of refrigerant gases in the raw material gas is preferably 80% by mass or more and 100% by mass or less, more preferably 90% by mass or more and 100% by mass or less, and even more preferably 95% by mass or more and 100 mol% by mass.

[0034] The raw material gas may contain other compounds in addition to the refrigerant gas. The boiling point of such other compounds may be, for example, -100°C or below, or -150°C or below. These other compounds are typically included in the above mixture as gases. Examples of such other compounds include nitrogen, oxygen, carbon dioxide, and water.

[0035] (First Module) The first module preferably permeates and / or adsorbs a portion of the raw material gas to separate it into a first separation gas and a first retention gas, which have different compositions from the raw material gas.

[0036] In one embodiment, the first module comprises a separation membrane. The separation membrane may be any membrane that can permeate and / or adsorb a portion of the source gas, preferably a porous membrane, and more preferably a molecular sieve membrane.

[0037] In this disclosure, at least one of the first module and the second module comprises a molecular sieve membrane. In one embodiment, the first module may comprise a molecular sieve membrane; in another embodiment, the second module may comprise a molecular sieve membrane; and in yet another embodiment, both the first module and the second module may comprise a molecular sieve membrane.

[0038] The molecular sieve membrane described above is a membrane that can permeate a portion of the source gas. In a preferred embodiment, the molecular sieve membrane may be one or more membranes selected from zeolite, silica, and organosilica.

[0039] (Zeolite) Zeolites are typically porous metal oxides based on aluminosilicate, and zeolites that have been assigned a skeletal code by the International Zeolite Society can be used. Hereinafter, when referring to zeolite (film), it means zeolite and / or zeolite film.

[0040] Examples of zeolite (film) include A-type, ferrielite, MCM-22, ZSM-5, mordenite, L-type, Y-type, X-type, and beta-type, with A-type, CHA-type, and ZSM-5-type being preferred.

[0041] In one embodiment, the compositional formula of the zeolite (film) is M ｎ＋ ２／ｎ O. (Al ２ O ３ )・(SiO ２ ) ｘ ・yH ２ It can be represented by O (where M is used in the formula). ｎ＋ (where n represents an n-valent metal cation, n is an integer from 1 to 5, x is an integer greater than or equal to 2, for example, an integer from 2 to 10, and y is an integer greater than or equal to 1, for example, an integer from 1 to 50.)

[0042] The silica / alumina ratio in the zeolite (film) is preferably 1.25 to 100, more preferably 5 to 50, and even more preferably 10 to 30. The above silica / alumina ratio is given by the above formula M ｎ＋ ２／ｎ O. (Al ２ O ３ )・(SiO ２ ) ｘ ・yH ２ This corresponds to x in O.

[0043] The average pore size of the zeolite (membrane) is preferably 2 Å to 10 Å, more preferably 3 Å to 8 Å, and even more preferably 3 Å to 6 Å. Having the average pore size of the zeolite within this range can improve the separation efficiency of fluorocarbon gases.

[0044] The average pore size in zeolite (membrane) can be calculated using the BJH method based on the pressure and nitrogen adsorption / desorption amount by measuring the nitrogen gas adsorption / desorption isotherm.

[0045] The porosity of zeolite (membrane) can be calculated using the t-plot method based on the pressure and nitrogen adsorption / desorption amount by measuring the nitrogen adsorption / desorption isotherm.

[0046] The thickness of the zeolite (film) is preferably 0.1 μm to 100 μm, more preferably 0.5 μm to 50 μm, and even more preferably 1 μm to 10 μm.

[0047] Zeolites (films) can be produced by hydrothermal synthesis in one embodiment. Typically, in hydrothermal synthesis, a raw material composition containing a silicon compound, an aluminum compound, a metal compound (but not a silicon compound or an aluminum compound), water, and a structure-directing agent as needed can be subjected to a hydrothermal synthesis reaction to synthesize zeolites. Seed crystals may be present during the hydrothermal synthesis reaction.

[0048] Examples of silicon compounds that can be used include silica sol, fumed silica, precipitated silica, aluminosilicate, and alkoxysilane.

[0049] Examples of the above-mentioned aluminum compounds include aluminum hydroxide, aluminum oxide, aluminum sulfate, aluminum chloride, aluminum nitrate, aluminosilicate, metallic aluminum, pseudoboehmite, alumina sol, and aluminum alkoxide.

[0050] Examples of the above-mentioned metal compounds include lithium hydroxide, sodium hydroxide, potassium hydroxide, and rubidium hydroxide.

[0051] Examples of the above-mentioned structure directing agents include CHA-type zeolites such as N,N,N-trialkyladamantanammonium cation, N,N,N-trimethylbenzylammonium cation, N-alkyl-3-quinuclidinol cation, N,N,N-trialkylexoaminonorbornane cation and N,N,N-trialkylcyclohexylammonium cation, N,N,N-trimethylbenzylammonium cation, and N,N,N-trialkylcyclohexylammonium cation; ZSM-5 type zeolites such as tetrapropylammonium cation and tetraethylammonium cation; and A type zeolites such as tetramethylammonium cation.

[0052] The silicon compound, aluminum compound, metal compound, water, and any structure-directing agent used as needed can be appropriately used depending on the desired structure of the zeolite.

[0053] The temperature of the above hydrothermal synthesis reaction is preferably 80°C to 200°C, more preferably 100°C to 180°C, and even more preferably 120°C to 160°C.

[0054] The above hydrothermal synthesis reaction is preferably carried out in a sealed container.

[0055] In one embodiment, if the first module includes a porous support and / or an intermediate layer, a zeolite (film) can be produced by coating the porous support and / or intermediate layer with zeolite seed crystals, and then immersing the porous support and / or intermediate layer coated with such seed crystals in the raw material composition and performing hydrothermal synthesis.

[0056] (Silica) The silica mentioned above is typically amorphous silica (film) formed by the sol-gel method (hereinafter also simply referred to as "amorphous silica (film)"). The amorphous silica (film) formed by the sol-gel method may typically be a porous amorphous silica (film) formed by the sol-gel method. In this disclosure, amorphous silica (film) means amorphous silica and / or amorphous silica film.

[0057] Amorphous silica (film) contains units represented by the formula: -Si-O-Si- (siloxane units), and may further have organic groups bonded to the Si atoms of the siloxane units.

[0058] In one embodiment, amorphous silica (film) has a large proportion of siloxane units (-Si-O-Si-). In this embodiment, for example, based on the total amount of silicon atoms contained in amorphous silica, the proportion of silicon atoms to which organic groups are bonded may be preferably 0 mol% to 20 mol%, more preferably 0 mol% to 10 mol%, and even more preferably 0 mol% to 5 mol%.

[0059] Based on the total amount of silicon atoms contained in amorphous silica (film), Si(O) １／２ ) ４ The proportion of silicon atoms represented by (i.e., silicon atoms bonded to four oxygen atoms) is preferably 80 mol% or more and 100 mol% or less, more preferably 90 mol% or more and 100 mol% or less, and even more preferably 95 mol% or more and 100 mol% or less.

[0060] In another embodiment, amorphous silica (film) comprises siloxane units (-Si-O-Si- units) and organic groups bonded to the Si atoms of the siloxane units, and preferably may comprise siloxane units and hydrocarbon groups bonded to the Si atoms of the siloxane units.

[0061] Based on the total amount of silicon atoms contained in amorphous silica (film), the proportion of silicon atoms to which organic groups are bonded is preferably 1 mol% to 50 mol%, more preferably 1 mol% to 20 mol%, and even more preferably 1 mol% to 10 mol%.

[0062] Based on the total amount of silicon atoms contained in amorphous silica (film), Si(O) １／２ ) ４ The proportion of silicon atoms represented by (i.e., silicon atoms bonded to four oxygen atoms) is preferably 50 mol% to 99 mol%, more preferably 80 mol% to 99 mol%, and even more preferably 90 mol% to 99 mol%.

[0063] In this disclosure, "organic group" means a monovalent or divalent or more carbon-containing group or a silsesquioxane group. Unless otherwise specified, an organic group may be a hydrocarbon group or a derivative thereof or a silsesquioxane group. A derivative of a hydrocarbon group may be a group having one or more N, O, S, Si, amide, sulfonyl, siloxane, carbonyl, carbonyloxy, etc., at the terminal or molecular chain of the hydrocarbon group.

[0064] Furthermore, in this disclosure, "hydrocarbon group" means a monovalent or divalent or more group containing carbon and hydrogen, obtained by removing one or more hydrogen atoms from a hydrocarbon. Such hydrocarbon groups are not particularly limited, but include C １－２０ Examples of hydrocarbon groups include aliphatic hydrocarbon groups and aromatic hydrocarbon groups. The "aliphatic hydrocarbon group" may be linear, branched, or cyclic, and may be saturated or unsaturated. The hydrocarbon group may also contain one or more ring structures. The hydrocarbon group may be substituted with one or more substituents.

[0065] In the use herein, the substituents of the "hydrocarbon group" are not particularly limited, but may be, for example, a halogen atom, or one or more halogen atoms, C １－６ alkyl group, C ２－６Alkenyl group, C ２－６ Alkynyl group, C ３－１０ Cycloalkyl groups, C ３－１０ Unsaturated cycloalkyl group, 5-10 membered heterocyclyl group, 5-10 membered unsaturated heterocyclyl group, C ６－１０ Examples include one or more groups selected from aryl groups and 5- to 10-membered heteroaryl groups.

[0066] The average pore diameter of the amorphous silica (membrane) is preferably 2 Å to 10 Å, more preferably 3 Å to 8 Å, and even more preferably 4 Å to 6 Å. Having the average pore diameter of the amorphous silica within this range can improve the separation efficiency of fluorocarbons.

[0067] The average pore diameter in amorphous silica (film) can be calculated based on the transmittance when two or more gases with different molecular diameters (hydrogen, nitrogen, carbon dioxide, tetrafluoromethane, sulfur hexafluoride, etc.) are permeated through it. Specifically, the transmittance of two or more gases with different molecular diameters is measured for each, the gas molecular diameter is plotted on the x-axis and the transmittance of each gas on the y-axis, and when the plots are connected by line segments, the transmittance is 10 －７ (mol / (m) ２ The average pore size (effective pore size) of amorphous silica is defined as the gas molecular diameter of s・Pa. The gas molecular diameter can be the dynamic molecular diameter, and as an example, it may be 2.9 Å for hydrogen gas, 3.6 Å for nitrogen gas, 4.7 Å for tetrafluoromethane gas, and 5.1 Å for sulfur hexafluoride. The dynamic molecular diameter may also be the value calculated by the above formula (x1).

[0068] The thickness of the amorphous silica (film) is preferably 1 nm to 1,000 nm, more preferably 5 nm to 500 nm, and even more preferably 10 nm to 300 nm.

[0069] Amorphous silica (films) can typically be manufactured by the sol-gel method.

[0070] The sol-gel method is a method for producing amorphous silica using silane compounds having hydrolyzable groups (hereinafter also simply referred to as "silane compounds") as raw materials, by hydrolysis and polycondensation of the silane compounds. In the sol-gel method, amorphous silica is formed by the hydrolysis and polycondensation of individual silane compounds, and it is thought that organic groups (hydrocarbon groups) tend to remain in the skeleton. Therefore, it is thought that the pore size, polarity, and hydrophilicity / hydrophobicity of amorphous silica can be easily controlled. In addition, the sol-gel method has features such as not requiring large-scale equipment compared to vapor deposition methods such as chemical vapor deposition (CVD).

[0071] The above sol-gel method can be carried out by a method comprising the following (a) to (c): (a) preparing a silica sol by mixing a silane compound having a hydrolyzable group with an aqueous medium; (b) preparing a precursor film using the above silica sol; and (c) heating the precursor film to obtain amorphous silica (film).

[0072] (a) In the silica sol preparation step (a), a silane compound having a hydrolyzable group is mixed with an aqueous medium to prepare a silica sol. By mixing the silane compound having a hydrolyzable group with the aqueous medium, the silane compound undergoes hydrolysis and polycondensation, yielding a silica sol containing a silica polymer (oligomer or polymer).

[0073] The silane compound having the above-mentioned hydrolyzable group is typically a compound having one or more silicon atoms and a hydrolyzable group bonded to the silicon atoms, and may also be a compound having a silicon atom, a hydrolyzable group bonded to the silicon atom, and an organic group bonded to the silicon atom.

[0074] The above organic group is synonymous with the organic group that can be contained in amorphous silica (film). Furthermore, the above hydrolyzable group is C １－１０ It can be one or more selected from alkoxy groups, halogen atoms, hydrogen atoms, and hydroxyl groups, preferably C １－１０ It may be an alkoxy group. Such C １－１０ The alkoxy group is preferably C １－４ It is an alkoxy group, more preferably C １－３It is an alkoxy group and specifically can be a methoxy group, an ethoxy group or a propoxy group.

[0075] As the silane compound having the above hydrolyzable group, the following formula: Si(X １ )(R ｎ )(R １ )(R ４－ｎ [In the formula, X １ represents a monovalent organic group, R １ each independently represents a hydrolyzable group, and n represents an integer of 0 to 3.], and the following formula: (R ２ )(R ３ Si—X ２ —Si(R ２ )(R ３ [In the formula, X ２ represents a divalent organic group, and R ２ each independently represents a hydrolyzable group.], and the compounds represented thereby are exemplified.

[0076] As the monovalent organic group represented by the above X １ , a monovalent hydrocarbon group or its derivative, a silsesquioxane group can be mentioned. The monovalent hydrocarbon group is preferably a C １－２０ hydrocarbon group, for example, a C １－２０ aliphatic hydrocarbon group, a C ６－２０ aromatic hydrocarbon group. The aliphatic hydrocarbon group may be linear, branched or cyclic, and may be saturated or unsaturated. Further, the hydrocarbon group may contain one or more ring structures. The monovalent hydrocarbon group may be substituted with one or more substituents. As the derivative of the monovalent hydrocarbon group, a C ３－１０ heterocyclic group such as a dioxanyl group, a triazolyl group, a pyridinyl group, a pyrazinyl group, a triazinyl group, an oxalylurea group, a group combining the C ３－１０ heterocyclic group and a C １－１０ alkylene group, a group combining the C ３－１０ heterocyclic group, an ether bond and a C １－１０ alkylene group, etc. can be mentioned. The above silsesquioxane group may be a silsesquioxane group such as a cage type or a ladder type.

[0077] As substituents of the above-mentioned "hydrocarbon group", for example, a halogen atom, a C which may be substituted by one or more halogen atoms １－６ alkyl group, C ２－６ alkenyl group, C ２－６ alkynyl group, C ３－１０ cycloalkyl group, C ３－１０ unsaturated cycloalkyl group, 5- to 10-membered heterocyclyl group, 5- to 10-membered unsaturated heterocyclyl group, C ６－１０ aryl group, 5- to 10-membered heteroaryl group, acetoxy group, amino group and hydroxy group, and one or more groups selected therefrom are exemplified.

[0078] X １ As the organic group represented by, a linear aliphatic hydrocarbon group which may have a substituent is preferable, and a C １－２０ linear aliphatic hydrocarbon group is more preferable, and a C １－１０ linear aliphatic hydrocarbon group is still more preferable. Specifically, it may be an alkanediyl group such as methyl group, ethyl group, butyl group, hexyl group, octyl group; an alkenyl group such as ethenyl group; an alkynyl group such as ethynyl group, and more preferably it may be a methyl group or an ethyl group. When the carbon number of X1 is small, it is considered that the organic group is difficult to bend and the pore diameter in the obtained amorphous silica tends to be uniform.

[0079] The divalent organic group represented by the above X ２ includes a divalent hydrocarbon group or a derivative thereof, and a silsesquioxane group. The divalent hydrocarbon group is preferably a C １－２０ hydrocarbon group, for example, C １－２０ aliphatic hydrocarbon group, C [[ID=(32]] ６－２０Examples include aromatic hydrocarbon groups. The aliphatic hydrocarbon group may be linear, branched, or cyclic, and may be saturated or unsaturated. The hydrocarbon group may also contain one or more ring structures. The divalent hydrocarbon group may be substituted with one or more substituents. Derivatives of the divalent hydrocarbon group include C15, triazolylene, viridinylene, pyradinylene, triadinylene, oxalylurea, etc. ３－１０ Heterocyclic group, the C ３－１０ Heterocyclic groups and C １－１０ A group combined with an alkylene group, the C ３－１０ Heterocyclic groups, ether bonds, and C １－１０ Examples include groups combined with alkylene groups. The silsesquioxane group may be a cage-type, ladder-type, or other type of silsesquioxane group.

[0080] The substituents of the above-mentioned "hydrocarbon group" may, for example, be substituted with a halogen atom, one or more halogen atoms, C １－６ alkyl group, C ２－６ Alkenyl group, C ２－６ Alkynyl group, C ３－１０ Cycloalkyl groups, C ３－１０ Unsaturated cycloalkyl group, 5-10 membered heterocyclyl group, 5-10 membered unsaturated heterocyclyl group, C ６－１０ Examples include one or more groups selected from aryl groups and 5- to 10-membered heteroaryl groups.

[0081] X ２ The organic group represented is an aliphatic hydrocarbon group which may have substituents, and a linear aliphatic hydrocarbon group is preferred. Specifically, an aliphatic hydrocarbon group which may have substituents １－２０ Linear aliphatic hydrocarbon groups are more preferred, C ２－１０ Linear aliphatic hydrocarbon groups are more preferred, and linear hydrocarbon groups are particularly preferred. Specifically, these may be alkanediyl groups such as ethylene, butanediyl, hexanediyl, and octanediyl groups; alkenediyl groups such as ethenediyl groups; and alkynediyl groups such as acetylenediyl groups, with ethylene groups being more preferred.２ It is thought that a smaller number of carbon atoms makes the organic groups less prone to bending, resulting in more uniform pore sizes in the resulting amorphous silica.

[0082] The above R １ The hydrolyzable group represented by C １－１０ It can be one or more selected from alkoxy groups, halogen atoms, hydrogen atoms, and hydroxyl groups, preferably C １－１０ It may be an alkoxy group. Such C １－１０ The alkoxy group is preferably C １－４ It is an alkoxy group, more preferably C １－３ It is an alkoxy group, and specifically, it may be a methoxy group, an ethoxy group, or a propoxy group.

[0083] The above R ２ The hydrolyzable group represented by C １－１０ It can be one or more selected from alkoxy groups, halogen atoms, hydrogen atoms, and hydroxyl groups, preferably C １－１０ It may be an alkoxy group. Such C １－１０ The alkoxy group is preferably C １－４ It is an alkoxy group, more preferably C １－３ It is an alkoxy group, and specifically, it may be a methoxy group, an ethoxy group, or a propoxy group.

[0084] The above n is an integer between 0 and 3, preferably an integer between 0 and 1, more preferably 0 in one embodiment, and more preferably 1 in another embodiment.

[0085] Si(X １ ) ｎ (R １ ) ４－ｎ Examples of silane compounds represented by include tetraalkoxysilanes such as tetramethoxysilane, tetraethoxysilane, and tetrapropoxysilane; and alkylalkoxysilanes such as methyltrimethoxysilane, methyltriethoxysilane, ethyltrimethoxysilane, ethyltriethoxysilane, vinyltrimethoxysilane, and vinyltriethoxysilane.

[0086] (R ２ )３ Si-X ２ -Si(R ２ ) ３ Examples of the compound represented by -Si(R) include bis(triethoxysilyl)ethane, bis(triethoxysilyl)butane, bis(triethoxysilyl)octane, bis(triethoxysilyl)ethylene, bis(triethoxysilyl)acetylene, and the like.

[0087] Examples of the aqueous medium include water and a mixture of water and a hydrophilic solvent. Examples of the hydrophilic solvent include alcohols such as methanol, ethanol, and propanol.

[0088] The method of mixing the silane compound and the aqueous medium is not particularly limited, and typically, it can be carried out by stirring a mixture of the silane compound and the aqueous medium.

[0089] When mixing the silane compound and the aqueous medium, a catalyst may coexist. The hydrolysis and polycondensation of the silane compound can be promoted by the catalyst. Examples of such a catalyst include acid catalysts such as hydrochloric acid, nitric acid, and acetic acid; and base catalysts such as ammonia.

[0090] (b) Preparation step of the precursor film In step (b), the precursor film is prepared using the silica sol. In the present disclosure, the precursor film contains a silica polymer (oligomer or polymer) and may contain a part of the aqueous medium.

[0091] The preparation of such a precursor film can typically be carried out by applying the silica sol obtained in step (a). When including the porous support and / or the porous intermediate layer, the silica sol may be applied on the porous support and / or the porous intermediate layer.

[0092] Examples of the application of the silica sol include spin coating, dip coating, and a method of dipping a non-woven fabric in the silica sol and then applying it, but are not limited thereto.

[0093] After applying the silica sol, typically, the precursor film can be prepared by drying the aqueous medium. Such drying can be carried out at room temperature.

[0094] (c) Heating step (c) involves heating the precursor film to obtain amorphous silica (film). Heating the precursor film can further promote the hydrolysis and polycondensation of the silica polymer (oligomer or polymer) in the silica sol, and amorphous silica is formed by the dense formation of siloxane bonds.

[0095] The heating temperature is preferably 100°C to 400°C, more preferably 100°C to 200°C. The heating time is preferably 10 minutes to 60 minutes, more preferably 15 minutes to 30 minutes. Heating under these conditions makes it easier for pores to form in amorphous silica, and when an organosilane compound having an organic group is used as the silane compound, the organic group can be preserved.

[0096] When manufacturing the amorphous silica (film) described above, steps (b) and (c) may be repeated two or more times. When steps (b) and (c) are repeated two or more times, the silica sol in step (b) may be applied onto the amorphous silica (film) formed in the preceding step (c).

[0097] (Organosilica) Organosilica can typically be a porous organosilica membrane.

[0098] Organosilica (film) is amorphous and typically comprises siloxane units (-Si-O-Si- units) and organic groups bonded to the Si atoms of the siloxane units, preferably comprising siloxane units and hydrocarbon groups bonded to the Si atoms of the siloxane units. In this disclosure, organosilica (film) means organosilica and / or organosilica film.

[0099] Based on the total amount of silicon atoms contained in the organosilica (film), the proportion of silicon atoms to which organic groups are bonded is preferably more than 50 mol% and 100 mol% or less, more preferably more than 80 mol% and 100 mol% or less, even more preferably more than 90 mol% and 100 mol% or less, and even more preferably more than 90 mol% and 100 mol% or less.

[0100] Based on the total amount of silicon atoms contained in organosilica (film), Si(O １／２ ) ４ The proportion of silicon atoms represented by (i.e., silicon atoms bonded to four oxygen atoms) is preferably 0 mol% or more and less than 50 mol%, more preferably 0 mol% or more and less than 20 mol%, even more preferably 0 mol% or more and less than 10 mol%, and even more preferably 0 mol% or more and less than 5 mol%.

[0101] Organosilica (film) preferably contains units represented by the following formula: -Si-X-Si- [wherein X represents a divalent organic group], and also by the following formula: -Si-X ３ -Si- [wherein, X ３ represents a hydrocarbon group. It is more preferable to include a unit represented by ].

[0102] It is believed that the inclusion of the above-mentioned units in organosilica (membrane) allows the divalent organic groups to act as spacers, thereby controlling the pore size, and that the presence of aliphatic hydrocarbon groups on the surface of the pores in organosilica can improve the separation efficiency of fluorocarbons.

[0103] Examples of the divalent organic group represented by X above include a divalent hydrocarbon group or its derivative, and a silsesquioxane group. The divalent hydrocarbon group is preferably C １－２０ Hydrocarbon groups, for example, C １－２０ Aliphatic hydrocarbon group, C ６－２０ Examples include aromatic hydrocarbon groups. The aliphatic hydrocarbon group may be linear, branched, or cyclic, and may be saturated or unsaturated. The hydrocarbon group may also contain one or more ring structures. The divalent hydrocarbon group may be substituted with one or more substituents. Derivatives of the divalent hydrocarbon group include C15, triazolylene, viridinylene, pyradinylene, triadinylene, oxalylurea, etc. ３－１０ Heterocyclic group, the C ３－１０ Heterocyclic groups and C １－１０ A group combined with an alkylene group, the C ３－１０ Heterocyclic groups, ether bonds, and C １－１０Examples include groups combined with alkylene groups. The silsesquioxane group may be a cage-type, ladder-type, or other type of silsesquioxane group.

[0104] The substituents of the above-mentioned "hydrocarbon group" may, for example, be substituted with a halogen atom, one or more halogen atoms, C １－６ alkyl group, C ２－６ Alkenyl group, C ２－６ Alkynyl group, C ３－１０ Cycloalkyl groups, C ３－１０ Unsaturated cycloalkyl group, 5-10 membered heterocyclyl group, 5-10 membered unsaturated heterocyclyl group, C ６－１０ Examples include one or more groups selected from aryl groups and 5- to 10-membered heteroaryl groups.

[0105] The organic group represented by X is an aliphatic hydrocarbon group which may have substituents, and a linear aliphatic hydrocarbon group is preferred. Specifically, a C which may have substituents. １－２０ Aliphatic hydrocarbon groups are more preferred, C ２－１０ Aliphatic hydrocarbon groups are more preferred, and linear hydrocarbon groups are particularly preferred. Specifically, these may be alkanediyl groups such as ethylene, butanediyl, hexanediyl, and octanediyl groups; alkenediyl groups such as ethenediyl groups; and alkynediyl groups such as acetylenediyl groups. From the viewpoint of the type of fluorocarbon gas to be separated, the pore size of the organosilica, and the availability of organosilane compounds, the organic group represented by X may more preferably be an ethylene group. It is thought that if the number of carbon atoms in X is small, the organic group is less likely to bend, and the pore size in the resulting organosilica tends to be more uniform.

[0106] In the above formula, X ３ X represents a hydrocarbon group. The number of carbon atoms in the hydrocarbon group is preferably 1 to 20, more preferably 2 to 12. ３ As for hydrocarbon groups represented by C １－２０ Aliphatic hydrocarbon groups are preferred, C ２－１０Aliphatic hydrocarbon groups are more preferred, and linear hydrocarbon groups are even more preferred. Specifically, examples include alkanediyl groups such as ethylene, butanediyl, hexanediyl, and octanediyl; alkenediyl groups such as ethylenediyl; and alkynediyl groups such as acetylenediyl. ３ Examples of aliphatic hydrocarbon groups represented by this include the ethylene group (-CH ２ CH ２ -), butanediyl group, octanediyl group, ethenediyl group (-CH=CH-), acetylenediyl group, and preferably ethylene group (-CH ２ CH ２ -) is even more preferable. ３ It is thought that a smaller number of carbon atoms makes the aliphatic hydrocarbon group less prone to bending, resulting in a more uniform pore size in organosilica.

[0107] The average pore diameter of the organosilica (membrane) is preferably 2 Å to 10 Å, more preferably 3 Å to 8 Å, and even more preferably 4 Å to 6 Å. Having the average pore diameter of the organosilica (membrane) within this range can improve the separation efficiency of fluorocarbons.

[0108] The average pore diameter in organosilica (membrane) can be calculated based on the transmittance when two or more gases with different molecular diameters (hydrogen, nitrogen, carbon dioxide, tetrafluoromethane, sulfur hexafluoride, etc.) are permeated through it. Specifically, the transmittance of two or more gases with different molecular diameters is measured for each, the gas molecular diameter is plotted on the x-axis and the transmittance of each gas on the y-axis, and when the plots are connected by line segments, the transmittance is 10 －７ (mol / (m) ２ The average pore size (effective pore size) of the organosilica is defined as the gas molecular diameter of s・Pa. The gas molecular diameter can be the dynamic molecular diameter, and for example, it may be 2.9 Å for hydrogen gas, 3.6 Å for nitrogen gas, 4.7 Å for tetrafluoromethane gas, and 5.1 Å for sulfur hexafluoride. The dynamic molecular diameter may also be the value calculated by the above formula (x1).

[0109] The thickness of the organosilica is preferably 1 nm to 1,000 nm, more preferably 5 nm to 500 nm, and even more preferably 10 nm to 300 nm.

[0110] Methods for producing organosilica (films) include, but are not limited to, the sol-gel method and chemical vapor deposition (CVD). Organosilica is preferably produced by the sol-gel method. The sol-gel method makes it possible to produce organosilica with a higher organic group content.

[0111] The above sol-gel method can typically be carried out by the sol-gel method. In one embodiment, such a sol-gel method can be carried out by a method comprising the following (a) to (c): (a) preparing an organosilane sol by mixing an organosilane compound with an aqueous medium; (b) preparing a precursor film using the above organosilane sol; and (c) heating the precursor film to obtain organosilica (film).

[0112] (a) Preparation of organosilane sol: In step (a), the organosilane compound is mixed with an aqueous medium to prepare the organosilane sol. By mixing the organosilane compound with the aqueous medium, the organosilane compound undergoes hydrolysis and polycondensation, yielding an organosilane sol containing a polymer (oligomer or polymer) of the organosilane compound.

[0113] The organosilane compounds described above may typically be compounds having one or more silicon atoms, an organic group bonded to the silicon atoms, and a hydrolyzable group bonded to the silicon atoms.

[0114] The above organic group is synonymous with the organic group contained in organosilica. Furthermore, the above hydrolyzable group is C １－１０ It can be one or more selected from alkoxy groups, halogen atoms, hydrogen atoms, and hydroxyl groups, preferably C １－１０ It may be an alkoxy group. Such C １－１０ The alkoxy group is preferably C １－４ It is an alkoxy group, more preferably C １－３It is an alkoxy group, and specifically, it may be a methoxy group, an ethoxy group, or a propoxy group.

[0115] The organosilane compound mentioned above is represented by the following formula: X ４ -Si(R ３ ) ３ [In the formula, X ４ R represents a monovalent organic group. ３ Each of these independently represents a hydrolyzable group. Compounds represented by ] and the following formula: (R ４ ) ３ Si-X ５ -Si(R ４ ) ３ [In the formula, X ５ R represents a divalent organic group. ２ Each of these independently represents a hydrolyzable group. Examples of compounds represented by ] include:

[0116] The above X ４ Examples of monovalent organic groups represented by include monovalent hydrocarbon groups or their derivatives, and silsesquioxane groups. The monovalent hydrocarbon group is preferably C １－２０ Hydrocarbon groups, for example, C １－２０ Aliphatic hydrocarbon group, C ６－２０ Examples include aromatic hydrocarbon groups. The aliphatic hydrocarbon group may be linear, branched, or cyclic, and may be saturated or unsaturated. The hydrocarbon group may also contain one or more ring structures. The monovalent hydrocarbon group may be substituted with one or more substituents. Examples of derivatives of the monovalent hydrocarbon group include C dioxanyl group, triazolyl group, viridinyl group, pyrazinyl group, triazinyl group, oxalylurea group, etc. ３－１０ Heterocyclic group, the C ３－１０ Heterocyclic groups and C １－１０ A group combined with an alkylene group, the C ３－１０ Heterocyclic groups, ether bonds, and C １－１０ Examples include groups combined with alkylene groups. The silsesquioxane group may be a cage-type, ladder-type, or other type of silsesquioxane group.

[0117] The substituents of the above-mentioned "hydrocarbon group" may, for example, be substituted with a halogen atom, one or more halogen atoms, C １－６ alkyl group, C ２－６ Alkenyl group, C ２－６ Alkynyl group, C ３－１０ Cycloalkyl groups, C ３－１０ Unsaturated cycloalkyl group, 5-10 membered heterocyclyl group, 5-10 membered unsaturated heterocyclyl group, C ６－１０ Examples include one or more groups selected from aryl groups, 5- to 10-membered heteroaryl groups, acetoxy groups, amino groups, and hydroxyl groups.

[0118] X ４ The organic group represented is preferably a linear aliphatic hydrocarbon group which may have substituents, and may have substituents. １－２０ Linear aliphatic hydrocarbon groups are more preferred, C １－１０ A linear aliphatic hydrocarbon group is more preferably a linear aliphatic hydrocarbon group, specifically an alkanediyl group such as a methyl group, ethyl group, butyl group, hexyl group, or octyl group; an alkenyl group such as an ethenyl group; or an alkynyl group such as an ethynyl group, and more preferably a methyl group or an ethyl group. ４ It is thought that a smaller number of carbon atoms makes the organic group less prone to bending, resulting in a more uniform pore size in the resulting organosilica.

[0119] The above X ５ Examples of divalent organic groups represented by include divalent hydrocarbon groups or their derivatives, and silsesquioxane groups. The divalent hydrocarbon group is preferably C １－２０ Hydrocarbon groups, for example, C １－２０ Aliphatic hydrocarbon group, C ６－２０Examples include aromatic hydrocarbon groups. The aliphatic hydrocarbon group may be linear, branched, or cyclic, and may be saturated or unsaturated. The hydrocarbon group may also contain one or more ring structures. The divalent hydrocarbon group may be substituted with one or more substituents. Derivatives of the divalent hydrocarbon group include C15, triazolylene, viridinylene, pyradinylene, triadinylene, oxalylurea, etc. ３－１０ Heterocyclic group, the C ３－１０ Heterocyclic groups and C １－１０ A group combined with an alkylene group, the C ３－１０ Heterocyclic groups, ether bonds, and C １－１０ Examples include groups combined with alkylene groups. The silsesquioxane group may be a cage-type, ladder-type, or other type of silsesquioxane group.

[0120] The substituents of the above-mentioned "hydrocarbon group" may, for example, be substituted with a halogen atom, one or more halogen atoms, C １－６ alkyl group, C ２－６ Alkenyl group, C ２－６ Alkynyl group, C ３－１０ Cycloalkyl groups, C ３－１０ Unsaturated cycloalkyl group, 5-10 membered heterocyclyl group, 5-10 membered unsaturated heterocyclyl group, C ６－１０ Examples include one or more groups selected from aryl groups and 5- to 10-membered heteroaryl groups.

[0121] X ５ The organic group represented is an aliphatic hydrocarbon group which may have substituents, and a linear aliphatic hydrocarbon group is preferred. Specifically, an aliphatic hydrocarbon group which may have substituents １－２０ Aliphatic hydrocarbon groups are more preferred, C ２－１０ Aliphatic hydrocarbon groups are more preferred, and linear hydrocarbon groups are particularly preferred. Specifically, these may be alkanediyl groups such as ethylene, butanediyl, hexanediyl, and octanediyl; alkenediyl groups such as ethenediyl; and alkynediyl groups such as acetylenediyl, with ethylene being more preferred. ５It is thought that a smaller number of carbon atoms makes the organic group less prone to bending, resulting in a more uniform pore size in the resulting organosilica.

[0122] The above R ３ The hydrolyzable group represented by C １－１０ It can be one or more selected from alkoxy groups, halogen atoms, hydrogen atoms, and hydroxyl groups, preferably C １－１０ It may be an alkoxy group. Such C １－１０ The alkoxy group is preferably C １－４ It is an alkoxy group, more preferably C １－３ It is an alkoxy group, and specifically, it may be a methoxy group, an ethoxy group, or a propoxy group.

[0123] The above R ４ The hydrolyzable group represented by C １－１０ It can be one or more selected from alkoxy groups, halogen atoms, hydrogen atoms, and hydroxyl groups, preferably C １－１０ It may be an alkoxy group. Such C １－１０ The alkoxy group is preferably C １－４ It is an alkoxy group, more preferably C １－３ It is an alkoxy group, and specifically, it may be a methoxy group, an ethoxy group, or a propoxy group.

[0124] X ４ -Si(R ３ ) ３ Examples of organosilane compounds represented by this formula include methyltrimethoxysilane, methyltriethoxysilane, ethyltrimethoxysilane, ethyltriethoxysilane, vinyltrimethoxysilane, and vinyltriethoxysilane.

[0125] (R ４ ) ３ Si-X ５ -Si(R ４ ) ３ Examples of compounds represented by this formula include bistriethoxysilylethane, bistriethoxysilylbutane, bistriethoxysilyloctane, bistriethoxysilylethylene, and bistriethoxysilylacetylene.

[0126] Examples of the aqueous medium include water and mixtures of water and a hydrophilic solvent. Examples of hydrophilic solvents include alcohols such as methanol, ethanol, and propanol.

[0127] The method for mixing the organosilane compound with the aqueous medium is not particularly limited, and can typically be carried out by stirring the mixture of the organosilane compound and the aqueous medium.

[0128] When mixing the above organosilane compound with an aqueous solvent, other silane compounds may be present. Such silane compounds may be of the following formula: Si(R ５ ) ４ [In the formula, R ５ Each of these independently represents a hydrolyzable group. Examples of compounds represented by ] include:

[0129] The above R ５ The hydrolyzable group represented by C １－１０ It can be one or more selected from alkoxy groups, halogen atoms, hydrogen atoms, and hydroxyl groups, preferably C １－１０ It may be an alkoxy group. Such C １－１０ The alkoxy group is preferably C １－４ It is an alkoxy group, more preferably C １－３ It is an alkoxy group, and specifically, it may be a methoxy group, an ethoxy group, or a propoxy group.

[0130] Si(R ５ ) ４ Examples of silane compounds represented by this formula include tetramethoxysilane, tetraethoxysilane, and tetrapropoxysilane.

[0131] When mixing the above organosilane compound with an aqueous medium, a catalyst may be present. The catalyst can promote the hydrolysis and polycondensation of the organosilane compound. Suitable catalysts include acid catalysts such as hydrochloric acid, nitric acid, and acetic acid; and base catalysts such as ammonia.

[0132] (b) Preparation of the precursor membrane: In step (b), the precursor membrane is prepared using the organosilane sol described above. In this disclosure, the precursor membrane comprises a polymer (oligomer or polymer) of the organosilane compound and may also comprise a portion of the aqueous medium described above.

[0133] The preparation of such a precursor film can typically be carried out by coating it with the organosilanesol obtained in step (a). If the porous support and / or porous intermediate layer is included, the organosilanesol may be coated onto the porous support and / or porous intermediate layer.

[0134] Methods for applying organosilanesols include, but are not limited to, spin coating, dip coating, and immersion of nonwoven fabric in organosilanesol.

[0135] After coating with the above organosilanesol, a precursor film can typically be prepared by drying an aqueous medium. This drying can be carried out at room temperature.

[0136] (c) Heating step (c) involves heating the precursor film to obtain organosilica (film). Heating the precursor film can further promote the hydrolysis and polycondensation of the polymer (oligomer or polymer) of the organosilane compound in the organosilane sol, and organosilica is formed by the dense formation of siloxane bonds.

[0137] The heating temperature is preferably 100°C to 400°C, more preferably 100°C to 200°C. The heating time is preferably 10 minutes to 60 minutes, more preferably 15 minutes to 30 minutes. Heating under these conditions facilitates the formation of pores in the organosilica and preserves the organic groups in the organosilica.

[0138] When manufacturing the organosilica (film) described above, steps (b) and (c) may be repeated two or more times. When steps (b) and (c) are repeated two or more times, the organosilica sol in step (b) may be applied onto the organosilica formed in the preceding step (c).

[0139] Examples of the above-mentioned chemical vapor deposition (CVD) method include the method described in Patrick HT Ngamou et al., "Plasma-deposited hybrid silica membranes with a controlled retention of organic bridges," Journal of Materials Chemistry A, 2013, 5567-5576.

[0140] In one embodiment, the molecular sieve membrane is a zeolite. In another embodiment, the molecular sieve membrane is silica. In yet another embodiment, the molecular sieve membrane is organosilica. Preferably, the molecular sieve membrane is organosilica.

[0141] The pore size of the molecular sieve membrane is preferably 2 Å to 10 Å, more preferably 3 Å to 8 Å, and even more preferably 4 Å to 6 Å.

[0142] The thickness of the molecular sieve film is preferably 1 nm to 100 μm, more preferably 5 nm to 50 μm, and even more preferably 10 nm to 10 μm.

[0143] The permeability of refrigerant gas A through the molecular sieve membrane is preferably 10 －９ mol / (m ２ ・s・Pa) or more, more preferably 10 －８ mol / (m ２ ・s・Pa) or more 10 －４ mol / (m ２ s・Pa) less than or equal to, more preferably 10 －７ mol / (m ２ ・s・Pa) or more 10 －５ mol / (m ２ The transmittance is less than or equal to s・Pa. By having the above transmittance within this range, separation efficiency can be further improved.

[0144] The permeability of refrigerant gas B through the molecular sieve membrane is preferably 10 １１ mol / (m ２ ・s・Pa) or more, more preferably 10 －１０ mol / (m ２ ・s・Pa) or more 10 －６mol / (m ２ s・Pa) less than or equal to, more preferably 10 －９ mol / (m ２ ・s・Pa) or more 10 －７ mol / (m ２ The transmittance is less than or equal to s・Pa. By having the above transmittance within this range, separation efficiency can be further improved.

[0145] Q is the permeability of refrigerant gas B through a molecular sieve membrane. Ｂ And the permeability Q of refrigerant gas A through the molecular sieve membrane. Ａ The ratio of Q Ｂ / Q Ａ The ratio is preferably 1 or more, more preferably 10 to 1000, and even more preferably 30 to 700. By having the above ratio within this range, the separation efficiency can be further improved.

[0146] Nitrogen permeability Q of molecular sieve membrane Ｎ２ and the SF of the molecular sieve membrane ６ Transparency Q ＳＦ６ The ratio of Q Ｎ２ / Q ＳＦ６ The ratio is preferably 100 or more, more preferably 120 to 2000, and even more preferably 150 to 1000. By having the above ratio within this range, the separation efficiency can be further improved.

[0147] The first module may further include a porous support. In an embodiment including a separation membrane (molecular sieve membrane) and a porous support, the first module may include the porous support and a separation membrane (preferably a molecular sieve membrane) disposed on the porous support.

[0148] The inclusion of a porous support in the first module enhances its stability. Furthermore, when supplying raw material gas to the first module, the permeability of the raw material gas to the first module can be increased, which is expected to improve separation efficiency.

[0149] The above-mentioned porous support may be either an inorganic porous support or an organic porous support.

[0150] Such an inorganic porous support may preferably be composed of inorganic materials such as silica, alumina, zirconia, silicon carbide, silicon nitride, and mixtures thereof. The inorganic porous support may more preferably be a porous alumina support.

[0151] The above-mentioned organic porous support may preferably be composed of a heat-resistant polymer. Examples of such heat-resistant polymers include polysulfone, polyethersulfone, sulfonated polysulfone, sulfonated polyethersulfone, polyimide, polytetrafluoroethylene, polyvinylidene fluoride, and derivatives thereof. In this disclosure, the heat-resistant polymer may be understood as a polymer having a glass transition temperature of 100°C or higher, and preferably as a polymer having a glass transition temperature of 200°C or higher.

[0152] The average pore diameter of the pores in the porous support described above is preferably 10 nm to 500 nm, more preferably 15 nm to 300 nm, and even more preferably 20 nm to 200 nm.

[0153] The first module may further include a porous intermediate layer between the porous support and the separation membrane (preferably a molecular sieve membrane). By including such a porous intermediate layer, the continuity of the pore sizes between the separation membrane (preferably a molecular sieve membrane) and the porous support can be increased, and it is expected that the permeability of the raw material gas in the first module can be further increased.

[0154] Such porous intermediate layers may be composed of either inorganic or organic materials, and are preferably composed of inorganic materials. Examples of such inorganic materials include silica, alumina, zirconia, silicon carbide, silicon nitride, and mixtures thereof. As for organic materials, heat-resistant polymer materials are preferred, and specifically include polysulfone, polyethersulfone, sulfonated polysulfone, sulfonated polyethersulfone, polyimide, polytetrafluoroethylene, polyvinylidene fluoride, and derivatives thereof.

[0155] The average pore diameter of the pores in the porous intermediate layer described above is preferably 0.5 nm to 30 nm, more preferably 0.7 nm to 20 nm, and even more preferably 1 nm to 10 nm.

[0156] The flow rate of the gas supplied to the first module may be between 0.001 kg / hour and 1,000 kg / hour, between 0.005 kg / hour and 500 kg / hour, and further between 0.01 kg / hour and 100 kg / hour. The gas supplied to the first module may include the raw material gas and the second holding gas.

[0157] The amount of gas supplied to the first module that permeates into the first module is preferably 10 －１０ (mol / (m) ２ ・s・Pa) or more 10 －４ (mol / (m) ２ ・s・Pa) less than or equal to 10 －９ (mol / (m) ２ ・s・Pa) or more 10 －５ (mol / (m) ２ s・Pa) less than or equal to, more preferably 10 －８ (mol / (m) ２ ・s・Pa) or more 10 －６ (mol / (m) ２ It may be less than or equal to sPa.

[0158] By carrying out the first step, a first separation gas having a different composition from the raw material gas and a first retention gas having a different composition from the raw material gas are obtained. The first separation gas is used in the second step. The first retention gas may, if necessary, be mixed with the raw material gas and used in the first step.

[0159] When the first holding gas is mixed with the raw material gas and used in the first process, the first holding gas may be mixed with the raw material gas after being pressurized.

[0160] In one embodiment, the concentration of refrigerant gas A in the first separated gas is higher than the concentration of refrigerant gas A in the raw material gas. In another embodiment, the concentration of refrigerant gas B in the first separated gas may be higher than the concentration of refrigerant gas B in the raw material gas.

[0161] Concentration C of refrigerant gas A in the first separated gas Ａ１ And the concentration C of refrigerant gas A in the raw material gas. Ａ０ C Ａ１ / C Ａ０ It is greater than 1, preferably 1.2 to 2.0, and more preferably 1.4 to 1.9.

[0162] In the first step, the differential pressure between the gas supplied to the first module and the first separated gas is preferably 100 kPa or more, more preferably 100 kPa to 1500 kPa, and even more preferably 200 kPa to 900 kPa. By having the differential pressure within this range, the separation efficiency can be further improved.

[0163] The temperature when carrying out the first step is preferably 300°C or lower, more preferably 10°C to 300°C, and more preferably 70°C to 150°C.

[0164] In the gas separation method of this disclosure, the first module and the second module may be connected in series or in parallel. In one embodiment, it is preferable that the first module and the second module are directly arranged.

[0165] In the second step, the first separation gas is supplied to the second module to obtain a second holding gas and a second separation gas, which have different compositions from the first separation gas.

[0166] (Second Module) The second module preferably permeates and / or adsorbs a portion of the first separation gas, separating it into a first separation gas and a first retention gas, which have different compositions from the first separation gas.

[0167] In one embodiment, the second module includes a separation membrane. The separation membrane may be any membrane that can permeate and / or adsorb a portion of the raw material gas, and may be the same as or different from the separation membrane in the first module. Preferably, the separation membrane is a molecular sieve membrane. The molecular sieve membrane in the second module may be the same as or different from the molecular sieve membrane in the first module.

[0168] The molecular sieve membrane in the second module can be made of the same material as the molecular sieve membrane used in the first module, and in a preferred embodiment, the molecular sieve membrane in the second module may be one or more membranes selected from the zeolite, silica, and organosilica mentioned above.

[0169] In one embodiment, the molecular sieve membrane that may be included in the second module is a zeolite. In another embodiment, the molecular sieve membrane that may be included in the second module is silica. In yet another embodiment, the molecular sieve membrane that may be included in the second module is organosilica. Preferably, the molecular sieve membrane that may be included in the second module is organosilica.

[0170] The pore size of the molecular sieve membrane that may be included in the second module is preferably 2 Å to 10 Å, more preferably 3 Å to 8 Å, and even more preferably 4 Å to 6 Å.

[0171] The thickness of the molecular sieve film that may be included in the second module is preferably 1 nm to 100 μm, more preferably 5 nm to 50 μm, and even more preferably 10 nm to 10 μm.

[0172] The permeability of the refrigerant gas A through the molecular sieve membrane that may be included in the second module is preferably 10 －９ mol / (m ２ ・s・Pa) or more, more preferably 10 －８ mol / (m ２ ・s・Pa) or more 10 －４ mol / (m ２ s・Pa) less than or equal to, more preferably 10 －７ mol / (m ２ ・s・Pa) or more 10 －５ mol / (m ２ The transmittance is less than or equal to s・Pa. By having the above transmittance within this range, separation efficiency can be further improved.

[0173] The permeability of the refrigerant gas B through the molecular sieve membrane that may be included in the second module is preferably 10 －１１ mol / (m ２ ・s・Pa) or more, more preferably 10 －１０ mol / (m ２ ・s・Pa) or more 10－６ mol / (m ２ s・Pa) less than or equal to, more preferably 10 －９ mol / (m ２ ・s・Pa) or more 10 －７ mol / (m ２ The transmittance is less than or equal to s・Pa. By having the above transmittance within this range, separation efficiency can be further improved.

[0174] The permeability Q of refrigerant gas B in a molecular sieve membrane that may be included in the second module. Ｂ And the permeability Q of refrigerant gas A through the molecular sieve membrane. Ａ The ratio of Q Ｂ / Q Ａ The ratio is preferably 1 or more, more preferably 10 to 1000, and even more preferably 30 to 700. By having the above ratio within this range, the separation efficiency can be further improved.

[0175] Nitrogen permeability Q of molecular sieve membranes that may be included in the second module Ｎ２ and the SF of the molecular sieve membrane ６ Transparency Q ＳＦ６ The ratio of Q Ｎ２ / Q ＳＦ６ The ratio is preferably 100 or more, more preferably 120 to 2000, and even more preferably 150 to 1000. By having the above ratio within this range, the separation efficiency can be further improved.

[0176] The second module may further include the porous intermediate layer between the porous support and the separation membrane (preferably a molecular sieve membrane). By including such a porous intermediate layer, the continuity of the pore sizes between the separation membrane (preferably a molecular sieve membrane) and the porous support can be increased, and it is expected that the permeability of the raw material gas in the first module can be further increased. Such a porous intermediate layer is synonymous with the porous intermediate layer that may be included in the first module.

[0177] The average pore diameter of the pores in the porous intermediate layer described above is preferably 0.5 nm to 30 nm, more preferably 0.7 nm to 20 nm, and even more preferably 1 nm to 10 nm.

[0178] The flow rate of the gas supplied to the second module may be between 0.001 kg / hour and 1,000 kg / hour, between 0.005 kg / hour and 500 kg / hour, and further between 0.01 kg / hour and 100 kg / hour. The gas supplied to the second module may include the first separation gas and the second retention gas.

[0179] The amount of gas supplied to the second module that permeates into the second module is preferably 10 －１０ (mol / (m) ２ ・s・Pa) or more 10 －４ (mol / (m) ２ ・s・Pa) less than or equal to 10 －９ (mol / (m) ２ ・s・Pa) or more 10 －５ (mol / (m) ２ s・Pa) less than or equal to, more preferably 10 －８ (mol / (m) ２ ・s・Pa) or more 10 －６ (mol / (m) ２ It may be less than or equal to sPa.

[0180] By carrying out the second step, a second separation gas with a different composition from the first separation gas and a second retention gas with a different composition from the raw material gas are obtained.

[0181] The second separation gas may be used as is as separation gas, or it may be subjected to a third step of supplying it to one or more gas separation modules. The gas supplied to the gas separation modules is separated into separation gas and retention gas, and by supplying the separation gas to the gas separation modules again, a further purified separation gas can be obtained.

[0182] It is preferable to mix the second holding gas with the raw material gas and then use it in the first step. This can increase the concentration of refrigerant gas A and / or refrigerant gas B in the raw material gas, thereby improving the separation efficiency.

[0183] It is also permissible to mix the second holding gas with the first separation gas and then use it for a second step. The second holding gas may be mixed with the first separation gas after being pressurized.

[0184] In one embodiment, the concentration of refrigerant gas A in the second separation gas is higher than the concentration of refrigerant gas A in the first separation gas. In another embodiment, the concentration of refrigerant gas B in the second separation gas may be higher than the concentration of refrigerant gas B in the first separation gas.

[0185] The content of refrigerant gas A in the second separated gas is preferably 60% by mass or more and 100% by mass or less, more preferably 80% by mass or more and 100% by mass or less, and even more preferably 90% by mass or more and 100% by mass or less.

[0186] Concentration C of refrigerant gas A in the second separated gas. Ａ２ And the concentration C of refrigerant gas A in the first separated gas. Ａ１ C Ａ２ / C Ａ１ It is greater than 1, preferably 1.05 or more and 1.5 or less, and more preferably 1.1 or more and 1.3 or less.

[0187] In the second step, the differential pressure between the gas supplied to the second module and the second separated gas is preferably 100 kPa or more, more preferably 100 kPa to 1500 kPa, and even more preferably 150 kPa to 1200 kPa. By having the differential pressure within this range, the separation efficiency can be further improved.

[0188] The temperature when carrying out the second step is preferably 300°C or lower, more preferably 10°C to 300°C, and more preferably 70°C to 150°C.

[0189] (Second Embodiment: Gas Separation Apparatus) The gas separation apparatus of the present disclosure comprises: a first module that separates a raw material gas containing at least refrigerant gas A and refrigerant gas B into a first separation gas and a first retention gas having different compositions from the raw material gas; and a second module that separates the first separation gas into a second separation gas and a second retention gas having different compositions from the first separation gas, wherein at least one of the first module and the second module is equipped with a molecular sieve membrane.

[0190] Refrigerant gas A, refrigerant gas B, raw material gas, first module, second module, molecular sieve membrane, first separation gas, first holding gas, second separation gas, and second holding gas have the same meaning as in the first embodiment, and preferred embodiments in the first embodiment also apply to the second embodiment.

[0191] Figure 1 schematically illustrates a two-stage gas separation apparatus as an example of the gas separation apparatus of this disclosure.

[0192] The gas separation apparatus 20 shown in Figure 1 comprises a first module 4a and a second module 4b. The raw material gas G0 is first supplied to the first module 4a, where it is separated into a first separation gas G1x and a first retaining gas G1y. The first separation gas is further supplied to the second module 4a, where it is separated into a second separation gas G2x and a second retaining gas G2y by the second module 4b. This allows for the separation of a predetermined refrigerant gas from the raw material gas.

[0193] In one embodiment, the refrigerant gas separated from the raw material gas may be refrigerant gas A.

[0194] Typically, the first module 4a and the second module 4b are connected via piping, and the raw material gas G0, the first separated gas G1x, the first retained gas G1y, the second separated gas G2x, and the second retained gas G2y are transported through the piping, respectively. The gas supplied to the first module includes the raw material gas and may also include the first retained gas and / or the second retained gas.

[0195] The flow rate of gas supplied to the first module may be between 0.001 kg / hour and 1,000 kg / hour, between 0.005 kg / hour and 500 kg / hour, and further between 0.01 kg / hour and 100 kg / hour.

[0196] The differential pressure between the gas supplied to the first module and the first separated gas is preferably 100 kPa or more, more preferably 100 kPa to 1500 kPa, and even more preferably 150 kPa to 1200 kPa. By having the differential pressure within this range, the separation efficiency can be further improved.

[0197] The amount of gas supplied to the first module that permeates into the first module is preferably 10 －１０ (mol / (m) ２ ・s・Pa) or more 10 －４ (mol / (m) ２ ・s・Pa) less than or equal to 10 －９ (mol / (m) ２ ・s・Pa) or more 10 －５ (mol / (m) ２ s・Pa) less than or equal to, more preferably 10 －８ (mol / (m) ２ ・s・Pa) or more 10 －６ (mol / (m) ２ It may be less than or equal to sPa.

[0198] The temperature of the first module is preferably 300°C or lower, more preferably 10°C to 300°C, and more preferably 70°C to 150°C.

[0199] In Figure 1, the first module 4a and the second module 4b are connected in series, but are not limited to this configuration; the first module 4a and the second module 4b may also be connected in parallel. The gas supplied to the second module may include the first separation gas and the second holding gas.

[0200] The flow rate of gas supplied to the second module may be between 0.001 kg / hour and 1,000 kg / hour, between 0.005 kg / hour and 500 kg / hour, and further between 0.01 kg / hour and 100 kg / hour.

[0201] The differential pressure between the gas supplied to the second module and the second separated gas is preferably 100 kPa or more, more preferably 100 kPa to 1500 kPa, and even more preferably 150 kPa to 1200 kPa. By having the differential pressure within this range, the separation efficiency can be further improved.

[0202] The amount of gas supplied to the second module that permeates into the second module is preferably 10 －１０ (mol / (m) ２ ・s・Pa) or more 10 －４ (mol / (m) ２・s・Pa) less than or equal to 10 －９ (mol / (m) ２ ・s・Pa) or more 10 －５ (mol / (m) ２ s・Pa) less than or equal to, more preferably 10 －８ (mol / (m) ２ ・s・Pa) or more 10 －６ (mol / (m) ２ It may be less than or equal to sPa.

[0203] The temperature of the second module is preferably 300°C or lower, more preferably 10°C to 300°C, and more preferably 70°C to 150°C.

[0204] As shown in Figure 2, the gas separation apparatus 20 of the present disclosure may further include a first piping 12 for recovering the second retained gas G2y and supplying it to the raw material gas G0. This can improve the separation efficiency. In one embodiment, if the concentration of refrigerant gas A in the second retained gas G2y is higher than the concentration of refrigerant gas A in the raw material gas G0, the concentration of refrigerant gas A in the gas supplied to the first module can be increased, thereby improving the separation efficiency of refrigerant gas A in the gas separation apparatus of the present disclosure.

[0205] As shown in Figure 3, if the gas separation apparatus 20 of this disclosure has a first pipe 12, a booster 13 may be provided in the first pipe 12. The second retained gas G2y obtained after passing through the first and second modules may have a lower pressure than the raw material gas G0. By adjusting the pressure of the second retained gas G2y with the booster 13, the supply of the second retained gas to the raw material gas can be stably carried out.

[0206] The pressure of the second retaining gas after pressurization is preferably 100 kPa or more and 1500 kPa or less as an absolute pressure, more preferably 150 kPa or more and 1200 kPa or less, and even more preferably 200 kPa or more and 900 kPa or less. By having the second retaining gas pressure within the above range, the separation efficiency can be further improved.

[0207] As shown in Figure 4, in the gas separation apparatus 20 of this disclosure, a booster 14 may be provided in the piping connecting the first module 4a and the second module 4b. When the raw material gas G0 passes through the first module 4a and is separated into the first separation gas G1x and the second holding gas G1y, the pressure may decrease. By providing the booster 14, the pressure of the first separation gas G1x can be increased, and the separation efficiency in the second module 4b can be further improved.

[0208] The pressure of the first separated gas after pressurization is preferably 100 kPa or more and 1500 kPa or less as an absolute pressure, more preferably 150 kPa or more and 1200 kPa or less, and even more preferably 200 kPa or more and 900 kPa or less. By having the pressure of the first separated gas within the above range, the separation efficiency can be further increased.

[0209] As shown in Figure 5, the gas separation apparatus 20 of this disclosure may further include a third module 4c in addition to the first module a and the second module 4b. The second separated gas G2x separated in the second module is further supplied to the third module 4c and separated into a third separated gas G3x and a third retained gas G3y, thereby obtaining a separated gas with an even higher concentration of a predetermined refrigerant gas. Such a gas separation apparatus 20 may further include the first piping 12, and may further include piping for recovering the third retained gas G3y and supplying it to the raw material gas G0 and / or the first separated gas G1x.

[0210] The gas separation apparatus of this disclosure may have piping for supplying other gases, such as nitrogen gas, to the raw material gas.

[0211] For example, in Figure 6, the raw material gas G0 and nitrogen gas are mixed, and if necessary, the second separation gas G2y is further mixed in and supplied to the first module 4a. At this time, the flow rate of the raw material gas G0 may be observed with a mass flow meter 5a, and the flow rate of the nitrogen gas may be observed with a mass flow meter 5b. The flow rate of the nitrogen gas can be adjusted with an on / off value 15. The flow rate of the second separation gas G2y can be adjusted with a valve 16a.

[0212] In the first module 4a, the raw material gas G0 is separated into the first separation gas G1x and the first retention gas G1y.

[0213] In the embodiment shown in Figure 6, the first separation gas G1x is pressurized by the booster 14 and then supplied to the second module 4b. At this time, the pressure of the first separation gas G1x may be observed by a pressure meter 17b, and the flow rate of the first separation gas G1x may be observed by a mass flow meter 5c. The booster 14 may be provided with a valve 16b. The composition of the first separation gas G1x may be analyzed by a gas composition analyzer 8. At this time, valves 16c and 16d may be provided in the piping that supplies the first separation gas G1x to the gas composition analyzer 8, so that the first separation gas G1x reaches the gas composition analyzer 8 only during analysis.

[0214] In the embodiment shown in Figure 6, the first retained gas G1y is recovered as is. A pressure regulator 2a may be provided in the piping for recovering the first retained gas G1y. By adjusting the pressure appropriately, the separation efficiency can be increased. When recovering the first retained gas G1y, the pressure of the first retained gas G1y may be observed using a pressure meter 17a, or the flow rate of the first retained gas G1y may be observed using a mass flow meter 5d.

[0215] The second module 5b separates the first separation gas G1x into the second separation gas G2x and the second retention gas G2y.

[0216] In the embodiment shown in Figure 6, the second separated gas G2x is recovered as a separated gas. The flow rate of the second separated gas G2x may be observed using a mass flow meter 5e. The composition of the second separated gas G2x may also be analyzed using a gas composition analyzer 8. In this case, a valve 16d may be provided in the piping that supplies the second separated gas G2x to the gas composition analyzer 8, so that the second separated gas G2x reaches the gas composition analyzer 8 only when analysis is required.

[0217] In the embodiment shown in Figure 6, the second holding gas G2y is pressurized by the booster 13, mixed with the raw material gas G0, and supplied to the first module G1x. Before supplying the second holding gas G2y to the booster 13, the back pressure may be adjusted by the pressure regulator 2b to stabilize the pressure. The pressure of the second holding gas G2y may also be observed by the pressure meter 17, and the flow rate of the second holding gas G2y may be observed by the mass flow meter 5f. The supply of the second holding gas is adjusted as appropriate by valves 16e and 16a.

[0218] The gas separation apparatus of this disclosure may be configured by combining each of the components shown in Figures 1 to 6. Furthermore, gas separation is possible even when only the first module is used as the module. The method using only the first module as the module is also called the one-stage membrane method, the method using the first and second modules is also called the two-stage membrane method, and the method using the first, second, and third modules is also called the three-stage membrane method.

[0219] The separation method of this disclosure provides a novel method for separating refrigerant gases and is preferably used for the separation of refrigerant gases.

[0220] The present invention will be further described in detail by the following examples, but the present invention is not limited thereto.

[0221] In the examples, the separation membranes shown in the table below were used. The pore diameters shown in the table are the average pore diameters calculated based on the transmittance when two gases with different molecular diameters (nitrogen and sulfur hexafluoride) were permeated through the membrane. Specifically, the transmittance was measured for two or more gases with different molecular diameters, and the gas molecular diameter was plotted on the x-axis and the transmittance of each gas on the y-axis. When the plots were connected by line segments, the transmittance was 10 －７ (mol / (m) ２ The gas molecular diameter at which the pressure becomes s・Pa was defined as the average pore size (effective pore size) of amorphous silica. The transmittance and transmittance ratio were measured at 200°C.

[0222]

[0223] (Test Examples 1-1 to 1-9) In Test Examples 1-1 to 1-9, gas separation was performed with a single separation membrane stage. R32 was supplied as refrigerant gas A and R125 as refrigerant gas B to the module equipped with the separation membrane. The supply gas and separation membrane supplied to the module were adjusted to the following conditions.

[0224]

[0225] The separation performance obtained by the above operation is shown in the table below. Hereinafter, R32 purity refers to the R32 content in the separated gas. Furthermore, R32 recovery rate refers to the ratio of the amount of R32 recovered in the separated gas to the amount of R32 contained in the raw material gas.

[0226]

[0227] (Test Examples 2-1 to 2-6) In Test Examples 2-1 to 2-4, gas separation was performed using a two-stage separation membrane. In the first membrane stage, R32 was supplied as refrigerant gas A and R125 as refrigerant gas B to the first module equipped with the separation membrane. In the second membrane stage, the first separated gas (supply gas) obtained in the first membrane stage was supplied to the second module equipped with the separation membrane. The supply gas and separation membrane supplied to each module were adjusted to the following conditions.

[0228]

[0229] The separation performance obtained by the above operation is shown in the table below.

[0230]

[0231] (Test Examples 3-1 to 3-16) In Test Examples 3-1 to 3-16, gas separation was performed using a two-stage separation membrane, and the second retained gas was recovered and supplied to the first module along with the raw material gas. In the first membrane stage, R32 as refrigerant gas A and R125 as refrigerant gas B were supplied to the first module equipped with the separation membrane along with the second retained gas. In the second membrane stage, the first separated gas (supply gas) obtained in the first membrane stage was supplied to the second module equipped with the separation membrane. The supply gas and separation membrane supplied to each module were adjusted to the following conditions.

[0232]

[0233] The separation performance obtained by the above operation is shown in the table below.

[0234]

[0235] (Test Examples 4-1 to 4-2) In Test Examples 4-1 to 4-2, gas separation was performed using a three-stage separation membrane. In the first membrane stage, R125 was supplied as refrigerant gas B to the first module equipped with the separation membrane. In the second membrane stage, the first separated gas (supply gas) obtained in the first membrane stage was supplied to the second module equipped with the separation membrane. In the third membrane stage, the second separated gas (supply gas) obtained in the second membrane stage was supplied to the fourth module equipped with the separation membrane. The supply gas and separation membrane supplied to each module were adjusted to the following conditions.

[0236]

[0237] The separation performance obtained by the above operation is shown in the table below.

[0238]

[0239] The separation method of this disclosure provides a novel method for separating refrigerant gases and is preferably used for the separation of refrigerant gases.

[0240] 2a-b Pressure regulator 3 Mass flow controller 4a First module 4b Second module 4c Third module 5a-f Mass flow meter 8 Gas composition analyzer 12 First piping 13, 14 Booster 15 On / off value 16a-e Valve 17a-c Pressure meter 20 Gas separation device G0 Raw gas G1x First separated gas G1y First retained gas G2x Second separated gas G2y Second retained gas G3x Third separated gas G3y Third retained gas

Claims

A first step involves supplying a raw material gas containing at least refrigerant gas A and refrigerant gas B to a first module to obtain a first separation gas and a first holding gas having a different composition from the raw material gas. The process includes a second step of supplying the first separation gas to a second module to obtain a second separation gas and a second retention gas having a different composition from the first separation gas, A gas separation method comprising a molecular sieve membrane in at least one of the first and second modules. 　 The gas separation method according to claim 1, wherein the first module and the second module are connected in series or in parallel. 　 The gas separation method according to claim 1 or 2, wherein in the first step, the second holding gas is supplied to the first module together with the raw material gas. 　 The gas separation method according to any one of claims 1 to 3, wherein the molecular sieve membrane comprises one or more membranes selected from zeolite, silica, and organosilica. 　 The gas separation method according to any one of claims 1 to 4, wherein the molecular sieve membrane includes an organosilica membrane. 　 The organosilica mentioned above is given by the following formula: -Si-X-Si- [In the formula, X represents a hydrocarbon group.] The gas separation method according to claim 5, comprising a unit represented by . 　 The aforementioned X is C ２－１２ The gas separation method according to claim 6, which represents a hydrocarbon group. 　 The permeability of the refrigerant gas A through the molecular sieve membrane is 10 －９ mol / (m ２ The pressure is 10 s·Pa or higher, and the permeability of the refrigerant gas B through the molecular sieve membrane is 10 －１１ mol / (m ２ A gas separation method according to any one of claims 1 to 7, wherein the pressure is s・Pa or higher. 　 The gas separation method according to any one of claims 1 to 8, wherein the pore size of the molecular sieve membrane is 2 Å or more and 10 Å or less. 　 The nitrogen permeability Q of the molecular sieve membrane Ｎ２ and the SF of the molecular sieve membrane ６ permeability Q ＳＦ６ and the ratio Q Ｎ２ / Q ＳＦ６ is 100 or more, The gas separation method according to any one of claims 1 to 9 　 The gas separation method according to any one of claims 1 to 10, wherein the differential pressure between the gas supplied to the first module and the first separated gas is 100 kPa or more. 　 The gas separation method according to any one of claims 1 to 11, wherein the first and second steps are carried out at a temperature of 300°C or less. 　 The gas separation method according to claim 3, further comprising pressurizing the second retaining gas before supplying the second retaining gas to the first module. 　 The refrigerant gas A is C ｎ Contains fluorocarbon, The refrigerant gas B is C ｎ＋ｍ Contains fluorocarbon, The gas separation method according to any one of claims 1 to 13, wherein n represents an integer of 1 or more, and m represents an integer of 1 or more. 　 The gas separation method according to any one of claims 1 to 14, wherein the refrigerant gas B contains R32 and the refrigerant gas B contains R125. 　 The gas separation method according to any one of claims 1 to 15, wherein the content of the refrigerant gas A is 20% by mass or more with respect to the total amount of the raw material gas. 　 The gas separation method according to any one of claims 1 to 16, wherein the content of refrigerant gas A in the second separated gas is 50% by mass or more. 　 The gas separation method according to any one of claims 1 to 17, wherein the content of refrigerant gas A in the second separated gas is 70% by mass or more. 　 The gas separation method according to any one of claims 1 to 18, wherein the content of refrigerant gas A in the second separated gas is 90% by mass or more. 　 A first module separates a raw material gas containing at least refrigerant gas A and refrigerant gas B into a first separation gas and a first holding gas having different compositions from the raw material gas, The system comprises a second module that separates the first separation gas into a second separation gas and a second retention gas, which have different compositions from the first separation gas, A gas separation apparatus comprising a first module and at least one of the second modules, each equipped with a molecular sieve membrane. 　 The gas separation apparatus according to claim 20, wherein the first module and the second module are connected in series or in parallel. 　 The gas separation apparatus according to claim 20 or 21, further comprising a first piping for recovering the second retaining gas and supplying it to the raw material gas. 　 The gas separation apparatus according to any one of claims 20 to 22, wherein the molecular sieve membrane comprises one or more membranes selected from zeolite, silica, and organosilica. 　 The gas separation apparatus according to any one of claims 20 to 23, wherein the molecular sieve membrane includes an organosilica membrane. 　 The organosilica mentioned above is given by the following formula: -Si-X-Si- [In the formula, X represents a hydrocarbon group.] The gas separation apparatus according to claim 24, comprising units represented by the following: 　 The aforementioned X is C ２－１２ A gas separation apparatus according to claim 25, representing a hydrocarbon group. 　 The permeability of the refrigerant gas A through the molecular sieve membrane is 10 －９ mol / (m ２ The pressure is 10 s·Pa or higher, and the permeability of the refrigerant gas B through the molecular sieve membrane is 10 －１１ mol / (m ２ A gas separation apparatus according to any one of claims 20 to 26, wherein the pressure is s・Pa or higher. 　 The gas separation apparatus according to any one of claims 20 to 27, wherein the pore size of the molecular sieve membrane is 2 Å or more and 10 Å or less. 　 The nitrogen permeability Q of the molecular sieve membrane. Ｎ２ and the SF of the molecular sieve membrane ６ Transparency Q ＳＦ６ The ratio of Q Ｎ２ / Q ＳＦ６ The gas separation apparatus according to any one of claims 20 to 28, wherein the value is 100 or more. 　 The gas separation apparatus according to any one of claims 20 to 29, wherein the differential pressure between the gas supplied to the first module and the first separated gas is 100 kPa or more. 　 The gas separation apparatus according to any one of claims 20 to 30, wherein the temperature of the first module and the second module is 300°C or less. 　 The gas separation apparatus according to claim 22, wherein the first piping has a pressure boosting device. 　 The refrigerant gas A is C ｎ Contains fluorocarbon, The refrigerant gas B is C ｎ＋ｍ Contains fluorocarbon, A gas separation apparatus according to any one of claims 20 to 32, wherein n represents an integer of 1 or more, and m represents an integer of 1 or more. 　 The gas separation apparatus according to any one of claims 20 to 33, wherein the refrigerant gas B contains R32 and the refrigerant gas B contains R125. 　 The gas separation apparatus according to any one of claims 20 to 34, wherein the content of the refrigerant gas A is 20% by mass or more with respect to the total amount of the raw material gas. 　 The gas separation apparatus according to any one of claims 20 to 35, wherein the content of refrigerant gas A in the second separated gas is 50% by mass or more. 　 The gas separation apparatus according to any one of claims 20 to 36, wherein the content of refrigerant gas A in the second separated gas is 70% by mass or more. 　 The gas separation apparatus according to any one of claims 20 to 37, wherein the content of refrigerant gas A in the second separated gas is 90% by mass or more.

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