Air separation apparatus and air separation method

Abstract

To provide an air separation device and an air separation method which use membrane separation at a low-temperature environment (-196°C to 0°C) near the dew point of a mixed gas containing an air component.SOLUTION: An air separation plant 101 comprises, in an internal space, a cold box (thermostatic tank) 20 for blocking heat entering from outside and a membrane module 1 positioned in the space.SELECTED DRAWING: Figure 5

Description

[Technical Field]

[0001] The present invention relates to an air separation apparatus and an air separation method. [Background technology]

[0002] The three main components of air (nitrogen, oxygen, and argon) are primarily separated using adsorption, cryogenic separation, and membrane separation.

[0003] Adsorption separation utilizes physical or chemical action to separate specific components from others by incorporating them into the adsorbent's site. For example, in a nitrogen / oxygen system using molecular sieves as the adsorbent, nitrogen exhibits strong adsorption, resulting in oxygen becoming the final product. Adsorption and desorption operations require pressure or temperature swings, but both are performed above room temperature. Desorption operations, in particular, become difficult at low temperatures.

[0004] Cryogenic separation separates air-based components through distillation utilizing vapor-liquid equilibrium. Because cryogenic separation requires operation under conditions where vapor and liquid coexist, the operating temperature is near the dew point (-196°C to -100°C), resulting in extremely low temperatures. Furthermore, cryogenic separation requires multiple compression and expansion strokes to provide the energy needed to liquefy and separate the air, necessitating tray columns and packed columns for distillation. Additionally, due to the constraints of vapor-liquid equilibrium, argon / oxygen systems are difficult to separate, requiring numerous distillation steps.

[0005] Membrane separation separates mixtures using the sieving action of membrane pores. Therefore, it is not subject to the constraints of vapor-liquid equilibrium, such as specific volatility. In membrane separation, higher molecular kinetic energy is generally advantageous for the mixture to pass through the pore barrier, so it is carried out at very high temperatures (e.g., 500°C to 800°C).

[0006] Patent Document 1 discloses a separation apparatus that combines distillation and membrane separation. [Prior art documents] [Patent Documents]

[0007] [Patent Document 1] U.S. Patent Application Publication No. 2010 / 0077796 [Overview of the Initiative] [Problems that the invention aims to solve]

[0008] However, membrane separation, when performed in phase (e.g., gas phase and gas phase), relies on the difference in molecular diffusivity and has a pore size distribution. As a result, separation membranes applicable to commercial operation, such as in nitrogen / oxygen systems, have not yet been obtained. Furthermore, the separation apparatus disclosed in Patent Document 1 uses a separation membrane made of an organic polymer membrane for membrane separation, which limits the operating temperature to approximately -90°C. Therefore, it was difficult to realize an air separation apparatus using membrane separation in low-temperature environments below the dew point of a mixed gas containing air components (-196°C to -100°C).

[0009] The present invention has been made in view of the above circumstances, and aims to provide an air separation apparatus and an air separation method that use membrane separation in a low-temperature environment (-196°C to -100°C), which is near the dew point of a mixed gas containing air components. [Means for solving the problem]

[0010] To solve the above problems, the present invention has the following configuration. [1] The inner space is enclosed by a constant temperature chamber to block heat from entering from the outside, An air separation device comprising a membrane module located in the aforementioned space. [2] The air separation apparatus according to [1], wherein the membrane module has a separation membrane on a support layer made of a porous substrate that selectively separates any component from a mixed gas containing air components. [3] A membrane module body in which the separation section having the separation membrane is located in the inner space, A raw material introduction unit for introducing raw materials containing air-based components into the main body of the membrane module, A permeable component extraction unit that extracts the component that permeates through the separation unit from the module body, The air separation apparatus according to [2] further comprises a non-permeable component discharge unit that discharges components that do not permeate the separation unit from the module body. [4] The air separation apparatus according to [2] or [3], wherein the support layer is hollow cylindrical. [5] The air separation apparatus according to any one of [2] to [4], wherein the separation membrane has a layer made of a hydrophobic material. [6] The air separation apparatus according to [5], wherein the hydrophobic material is an inorganic material having siloxane bonds. [7] The air separation apparatus according to [5] or [6], wherein the separation membrane is a laminated membrane of an active separation layer and an intermediate layer made of the hydrophobic material. [8] The air separation apparatus according to [7], wherein the active separation layer is a layer made of an inorganic material having a siloxane bond crosslinking structure. [9] An air separation apparatus according to any one of [1] to [8], wherein the dew point of moisture contained in the mixed gas containing air components is -50°C or lower.

[10] Further comprising a main heat exchanger that cools a mixed gas containing air components to a temperature near the dew point, An air separation apparatus according to any one of [1] to [9], wherein the membrane module is located on the secondary side of the main heat exchanger.

[11] An air separation apparatus according to any one of [1] to

[10] , further comprising one or more distillation columns.

[12] An air separation method for selectively separating a desired component from a mixed gas containing air components using a separation membrane at a temperature near the dew point of the mixed gas containing air components. [Effects of the Invention]

[0011] The air separation apparatus and air separation method of the present invention can utilize membrane separation in a low-temperature environment (-196°C to -100°C), which is the temperature of the mixed gas containing air components. [Brief explanation of the drawing]

[0012] [Figure 1] It is a cross-sectional view schematically showing the configuration of a membrane module applicable to an air separation device which is an embodiment to which the present invention is applied. [Figure 2] It is a cross-sectional view showing an example of the configuration of a separation unit applicable to a membrane module applicable to an air separation device which is an embodiment to which the present invention is applied. [Figure 3] It is an enlarged cross-sectional photograph showing a separation membrane applicable to an air separation device which is an embodiment to which the present invention is applied. [Figure 4] It is a schematic diagram showing an example of an inorganic material having a crosslinked structure of a siloxane bond, where (a) shows a structural diagram of a bridged organosilica and (b) shows a structural diagram of a side-chain organosilica, respectively. [Figure 5] It is a block diagram showing an example of the configuration of an air separation device which is an embodiment to which the present invention is applied. [Figure 6] It is a block diagram showing a modified example of the configuration of an air separation device which is an embodiment to which the present invention is applied. [Figure 7] It is a block diagram showing a modified example of the configuration of an air separation device which is an embodiment to which the present invention is applied. [Figure 8] It is a block diagram showing a modified example of the configuration of an air separation device which is an embodiment to which the present invention is applied. [Figure 9] It is a diagram showing the temperature dependence of the permeation rate of various gases in the separation unit (separation membrane) of the example. [Figure 10] It is a diagram showing the temperature dependence of the permeation rate of various gases in the separation unit (separation membrane) of the comparative example. [[ID=​​​​​​​​​The air separation apparatus and air separation method of the present invention will be described in detail below with reference to the drawings, along with the separation membrane and membrane module used therein. Note that, for the sake of clarity, the drawings used in the following description may show enlarged versions of key features, and the dimensional ratios of each component may not be the same as those in reality.

[0014] Furthermore, when "~" is used to indicate a numerical range in this specification, the numbers written before and after "~" are included as the lower and upper limits, respectively.

[0015] <Membrane Module> First, the configuration of a membrane module applicable to an air separation apparatus, which is one embodiment of the present invention, will be described. Figure 1 is a schematic cross-sectional view showing the configuration of a membrane module applicable to an air separation apparatus, which is one embodiment to which the present invention is applied. As shown in Figure 1, the membrane module 1 is generally configured to include a membrane module body 2, a separation unit 3, a raw material introduction section 4, a permeable component discharge section 5, and a non-permeable component discharge section 6.

[0016] The membrane module body 2 is a cylindrical container having a sealed space 2A inside. The membrane module body 2 is provided with a raw material introduction section 4 at one end and a permeable component discharge section 5 at the other end. The membrane module body 2 is also provided with a non-permeable component discharge section 6 in the cylindrical body. Furthermore, the separation unit 3 is located in the inner space 2A of the membrane module body 2.

[0017] Figure 2 is a cross-sectional view showing an example of the configuration of a separation unit 3 of a membrane module 1 applicable to an air separation device, which is one embodiment to which the present invention is applied. As shown in Figures 1 and 2, the separation unit 3 extends axially from the membrane module body 2 and is a hollow cylindrical member with a closed end on the raw material introduction section 4 side and an open end on the permeate component discharge section 5 side. The separation unit 3 has a separation section 3A and a support section 3B.

[0018] The separation section 3A is located near the end of the separation unit 3 on the raw material introduction section 4 side. The separation section 3A also has a separation membrane 10 on the support layer 7 for separating air-based components.

[0019] The support layer 7 is a hollow cylindrical member that supports the separation membrane 10. By supporting the separation membrane 10 on the support layer 7, the mechanical strength of the separation section 3A can be increased.

[0020] The material of the support layer 7 is not particularly limited as long as it is a porous substrate that allows air-based components, which are the raw materials, to pass through. The porous substrate may be either an inorganic porous material or an organic porous material, and it is preferable that it has sufficient strength to withstand industrial use. Furthermore, in order to increase the permeability of the separation membrane 10, it is preferable that the pore size and porosity of the porous substrate be large. The average pore size of the porous substrate is preferably about 0.05 μm to 10 μm. If the pore size is too large, the difference with the pore size of the separation membrane becomes too large, and if the pore size is too small, the permeability decreases. More preferably, it is 0.1 μm to 5 μm, and particularly preferably 0.5 μm to 3 μm.

[0021] Examples of porous substrates include ceramics made from alumina (α-Al2O3 (α-alumina), γ-Al2O3 (γ-alumina)), mullite, zirconia, titania, or composites thereof. Among these, ceramics mainly composed of α-alumina are preferred because they are inexpensive, readily available, and have excellent chemical resistance, heat resistance, and strength.

[0022] The shape of the support layer 7 is not particularly limited, but it is preferably cylindrical or plate-shaped. More specifically, the support layer 7 can be a porous alumina tube (average pore size: 1 μm, porosity: approximately 50%).

[0023] The support portion 3B is a hollow cylindrical member. The space inside the support portion 3B, together with the space inside the support layer 7 that constitutes the separation portion 3A, forms a flow path for the component (permeate gas) that permeates through the separation portion 3A.

[0024] The material of the support section 3B is not particularly limited, as long as it does not allow the air components of the raw material to permeate it. Examples of such materials include non-porous alumina tubes and Pyrex glass tubes. Among these, non-porous alumina tubes are preferable when considering the pressure resistance at the operating pressure (0.5 MPa) of the air separation device and its use at extremely low temperatures.

[0025] The separation unit 3 is constructed by fixing the separation section 3A and the support section 3B to each other with an intermediate material (not shown) in between. The material of the intermediate material is not particularly limited as long as it mitigates the difference in thermal expansion coefficients between the separation section (support layer 7) 3A and the support section 3B. Examples of such materials include glass frit.

[0026] The shape of the separation unit 3 is not particularly limited as long as it has a cylindrical space inside, and can be appropriately selected according to the area and application of the separation membrane 10. Examples of the separation unit 3's shape include cylindrical and rectangular prism shapes.

[0027] As shown in Figure 1, the raw material introduction section 4 is located at one end of the membrane module body 2. The raw material introduction section 4 is a gas component inlet that introduces raw materials containing air-based components into the inner space 2A of the membrane module body 2.

[0028] The raw material is a mixed gas containing one or more of the three major components of air—nitrogen, oxygen, and argon—and containing two or more components overall, or air itself. Examples of gas components other than air-based components include carbon dioxide, neon, hydrogen, helium, krypton, and xenon. When the raw material is a mixed gas containing air-based components, the ratio of each component in the raw material is not particularly limited. Furthermore, since the membrane module 1 is used under the operating conditions of the air separation device (-196°C to 0°C), it is preferable that the mixed gas used as the raw material does not contain components that solidify in the above temperature range, such as water and carbon dioxide. In particular, the amount of water in the mixed gas to be separated should have a dew point of -50°C or lower, preferably -70°C or lower, and more preferably -100°C or lower.

[0029] The permeate component outlet 5 is located at the other end of the membrane module body 2. The permeate component outlet 5 is a gas component outlet that discharges the components (permeate gas) that permeate through the separation section 3A (i.e., the separation membrane 10) of the separation unit 3 from the membrane module body 2.

[0030] The permeate component outlet 5 is connected in a sealed state to the open end of the separation unit 3 and is in communication with the space inside the support portion 3 that constitutes the separation unit 3. This allows the component (permeate gas) that permeates through the separation portion 3A of the separation unit 3 to be discharged from the permeate component outlet 5 to the outside of the membrane module body 2.

[0031] The non-permeable component outlet 6 is located in the body of the membrane module body 2. The non-permeable component outlet 6 is a gas component outlet that discharges components (non-permeable gases) that do not permeate the separation section 3A of the separation unit 3 (i.e., the separation membrane 10) from the space 2A inside the membrane module body 2.

[0032] The membrane module 1 selectively separates any component from a mixed gas containing air components under operating conditions within the temperature range (-196°C to 0°C) of the air separation apparatus. In other words, the raw material air, or a mixed gas containing air-based components, is cooled to the above temperature range beforehand. Furthermore, the membrane module 1 is placed inside a constant temperature chamber (cold box) to block heat intrusion from the outside during the operation of the air separation device, and is maintained at a temperature similar to that of the raw material gas.

[0033] <Separation membrane> Next, we will describe the configuration of a separation membrane applicable to an air separation apparatus, which is one embodiment to which the present invention is applied, using the case where it is applied to the membrane module 1 described above as an example. Figure 3 is an enlarged cross-sectional photograph showing a separation membrane 10, which is one embodiment to which the present invention is applied.

[0034] As shown in Figure 3, the separation membrane 10 of this embodiment is a laminated membrane consisting of an intermediate layer 8 supported on a support layer 7 and an active separation layer 9.

[0035] The intermediate layer 8 is located on the support layer 7 and supports the active separation layer 9. By providing the intermediate layer 8 between the support layer 7 and the active separation layer 9, the difference in average pore diameter between adjacent layers can be reduced. In this case, the intermediate layer 8 has an average pore diameter that is smaller than the average pore diameter of the support layer 7 and larger than the average pore diameter of the active separation layer 9.

[0036] The intermediate layer 8 is a layer made of hydrophobic material. Examples of hydrophobic materials include inorganic materials having siloxane bonds (-Si-O-Si-) and carbon materials composed of carbon. Among these, inorganic materials having siloxane bonds are preferred from the viewpoint of low-temperature resistance.

[0037] In this case, if a hydrophilic material is used as the intermediate layer 8, even if high-temperature firing with an inert gas is performed, some moisture that cannot be completely removed remains in the membrane pores. Therefore, at temperatures below 0°C, the moisture remaining in the membrane pores freezes, causing physical blockage and inhibiting gas permeability. In contrast, with the separation membrane 10 of this embodiment, since the intermediate layer 8 is made of a hydrophobic material, no moisture remains in the membrane pores after high-temperature firing, and even at low temperatures below 0°C, blockage due to freezing of residual moisture does not occur, and gas permeability is not inhibited.

[0038] Examples of inorganic materials containing siloxane bonds include sols prepared from organoalkoxysilanes and sols prepared from tetraethoxysilanes. Among these, from the viewpoint of controlling pore size, it is preferable to use a sol prepared from organoalkoxysilanes.

[0039] Examples of organoalkoxysilanes include one or more precursors selected from 1,2-bis(triethoxysilyl)methane (BTESM), 1,2-bis(triethoxysilyl)ethane (BTESE), 1,2-bis(triethoxysilyl)propane (BTESP), and 1,2-bis(triethoxysilyl)benzene (BTESB), and one or more sols obtained from their hydrolysates. Among these, BTESM or BTESE, which are crosslinked with at least a C3 component, preferably with a C2 or lower component, are preferred from the viewpoint of exhibiting properties similar to inorganic materials.

[0040] Examples of gel structures formed by calcining a sol prepared from organoalkoxysilane include cross-linked organosilica represented by the following general formula (1) and side-chain organosilica represented by the following general formula (2).

[0041] [ka]

[0042] [ka]

[0043] In the above general formula (1), the linking group X located between silicon atoms (Si) is an unsaturated hydrocarbon having unsaturated bonds between carbon atoms. The number of carbon atoms in the above unsaturated hydrocarbon is 1 to 6, and preferably 1 to 3. Furthermore, the aforementioned linking group X also includes structures in which some of the hydrogen atoms are replaced by elemental metal ions or compounds such as metal oxides. Examples of metal species that constitute the above-mentioned metal ions or metal oxides include Ag, Cu, Fe, Ni, Co, Al, Ti, and Zr. Note that the metal species listed here are merely examples and are not necessarily limited to these metals.

[0044] Furthermore, in the general formula (1) above, the organic group R is an unsaturated hydrocarbon having unsaturated bonds between hydrogen atoms or carbon atoms with 1 to 10 carbon atoms. The organic group R also includes structures in which some of the hydrogen atoms are replaced by elemental metal ions or compounds such as metal oxides. Examples of metal species that constitute the above-mentioned metal ions or metal oxides include Ag, Cu, Fe, Ni, Co, Al, Ti, and Zr. Note that the metal species listed here are merely examples and are not necessarily limited to these metals.

[0045] In the above general formula (2), the organic group R can be the same as that in the above general formula (1). Furthermore, in the general formula (2) above, OR' is a side chain (pendant) attached to the siloxane bond, and examples of the organic group R' include CH3 and C2H5.

[0046] Examples of side-chain organosilica represented by the above general formula (2) include methyltriethoxysilane (MTES) and methyltrimethoxysilane (MTMS).

[0047] Examples of carbon materials composed of carbon include carbon films.

[0048] The average pore size of the intermediate layer 8 is not particularly limited, as long as it is smaller than the average pore size of the support layer 7 and larger than the average pore size of the active separation layer 9. It is particularly preferable that the average pore size of the intermediate layer 8 be approximately 2 nm or less. Note that if the average pore size of the intermediate layer 8 is too large, the selectivity during gas separation will decrease. Conversely, if the average pore size of the intermediate layer 8 is too small, the gas permeability will decrease.

[0049] The thickness of the intermediate layer 8 is not particularly limited, as long as it is thick enough to cover the irregularities on the upper surface of the support layer 7 and flatten the active separation layer 9. Examples of such thicknesses include 10 to 500 nm, preferably 50 to 400 nm, and more preferably 100 to 200 nm.

[0050] The activated separation layer 9 is located on the intermediate layer 8 and is a layer that selectively separates desired components from the mixed gas containing the raw material, which is the air-based component. The material of the active separation layer 9 is not particularly limited, as long as it can selectively separate any component from a mixed gas containing air components. Examples of such materials include inorganic materials having a siloxane bond crosslinking structure with organoalkoxysilane as a precursor, and inorganic materials composed of metal oxides such as zirconia, titanium, and iron. Among these, it is preferable to use an inorganic material having a siloxane bond crosslinking structure with organoalkoxysilane as a precursor, from the viewpoint of controlling pore size and hydrophobicity.

[0051] Examples of inorganic materials having a siloxane bond crosslinking structure include sols prepared from organoalkoxysilanes and sols prepared from tetraethoxylanes. Among these, it is preferable to use sols prepared from organoalkoxysilanes from the viewpoint of controlling pore size. By controlling the pore size, it can also be applied to the separation of gases with high diffusion coefficients, such as helium and hydrogen, from mixed gases containing air components.

[0052] Examples of organoalkoxysilanes include one or more precursors selected from 1,2-bis(triethoxysilyl)methane (BTESM), 1,2-bis(triethoxysilyl)ethane (BTESE), 1,2-bis(triethoxysilyl)propane (BTESP), and 1,2-bis(triethoxysilyl)benzene (BTESB), and one or more sols obtained from their hydrolysates. Among these, those with three or fewer carbon atoms in the organic group R (BTESM, BTESE, BTESP) are preferred from the viewpoint of exhibiting properties similar to inorganic materials. This reflects the conventional finding that as the number of carbon atoms in the organic group R increases, it begins to exhibit the properties of organic materials.

[0053] Examples of gel structures formed by calcining a sol prepared from organoalkoxysilane include cross-linked organosilica represented by the following general formula (3) and side-chain organosilica represented by the following general formula (4).

[0054] [ka]

[0055] [ka]

[0056] In the above general formula (3), the linking group X located between silicon atoms (Si) is an unsaturated hydrocarbon having unsaturated bonds between carbon atoms. The number of carbon atoms in the above unsaturated hydrocarbon is 1 to 6, and preferably 1 to 3. Furthermore, the aforementioned linking group X also includes structures in which some of the hydrogen atoms are replaced by elemental metal ions or compounds such as metal oxides. Examples of metal species that constitute the above-mentioned metal ions or metal oxides include Ag, Cu, Fe, Ni, Co, Al, Ti, and Zr. Note that the metal species listed here are merely examples and are not necessarily limited to these metals.

[0057] Furthermore, in the general formula (3) above, the organic group R is an unsaturated hydrocarbon having an unsaturated bond between a hydrogen atom or carbon atoms with 1 to 10 carbon atoms. The organic group R also includes structures in which some of the hydrogen atoms are replaced by elemental metal ions or compounds such as metal oxides. Examples of metal species that constitute the above-mentioned metal ions or metal oxides include Ag, Cu, Fe, Ni, Co, Al, Ti, and Zr. Note that the metal species listed here are merely examples and are not necessarily limited to these metals.

[0058] In the above general formula (4), the organic group R can be the same as that in the above general formula (3). Furthermore, in the general formula (4) above, OR' is a side chain (pendant) attached to the siloxane bond, and examples of the organic group R' include CH3 and C2H5.

[0059] Examples of side-chain organosilica represented by the above general formula (4) include methyltriethoxysilane (MTES) and methyltrimethoxysilane (MTMS).

[0060] Figure 4 is a schematic diagram showing an example of an inorganic material having a siloxane bond crosslinking structure, where (a) is a structural diagram of a crosslinked organosilica and (b) is a structural diagram of a side-chain organosilica. As the active separation layer 9, it is preferable to use a gel in which the siloxane bonds are substituted with linking groups X, as shown in Figure 4(a). The linking group X is not particularly limited and can be appropriately selected depending on the type of gas to be separated. Examples of linking group X include alkyl groups having 1 to 8 carbon atoms and aromatic groups such as phenyl groups.

[0061] Inorganic materials composed of metal oxides such as zirconia, cobalt, nickel, aluminum, and iron include, for example, composites of precursors such as TEOS and metal nitrates. Among these, cobalt and nickel are preferred from the viewpoint of water vapor resistance. Depending on the target of separation and the separation environment, it can also be applied to the separation of hydrocarbon gases such as hydrogen and propane / propylene from mixed gases containing air components.

[0062] The average pore size of the active separation layer 9 is preferably 1 nm or less. Within this range, oxygen can be selectively separated from a mixed gas containing air components.

[0063] Specifically, for example, if the average pore size of the active separation layer 9 is 1 nm or less, oxygen can be selectively separated from a mixed gas containing air components. When selectively separating oxygen from a mixed gas containing air components, the average pore size of the active separation layer 9 is more preferably 0.1 nm to 0.8 nm, and particularly preferably 0.2 nm to 0.6 nm.

[0064] The thickness of the active separation layer 9 is not particularly limited, as long as it is a thickness that allows for the selective separation of any component from a mixed gas containing air components. Examples of such thicknesses include 200 to 300 nm, preferably 100 to 200 nm, and more preferably 50 to 100 nm.

[0065] The separation membrane 10 selectively separates any component from a mixed gas containing air components under operating conditions within the temperature range (-196°C to 0°C) of the air separation apparatus. Here, "permeance," an indicator of the performance of the separation membrane, is defined as the value obtained by dividing the molar flow rate that has permeated the membrane by the outer surface area of ​​the membrane and the gas partial pressure.

[0066] For example, if a gel obtained from BTESP is used as the active separation layer 9 and a gel prepared from BTESE is used as the intermediate layer 8, the separation membrane 10 becomes an oxygen separation membrane that permeates oxygen from a mixed gas containing air components. In this case, the performance of the separation membrane 10 of this embodiment is such that, under operating conditions of -196°C to 0°C, the oxygen permeability is at least 1 × 10⁻¹⁰. -8 [mol / (m 2 (·s·Pa) or more, 1 × 10 -6 [mol / (m 2 It is preferable that the value is above (·s·Pa).

[0067] Furthermore, if the separation membrane 10 is an oxygen separation membrane, the performance of the separation membrane 10 preferably has an oxygen / argon permeability ratio of at least 4, and more preferably 10 or higher. With such performance, the separation membrane 10 can be used to separate oxygen and argon from a mixed gas containing oxygen and argon.

[0068] (Method for manufacturing separation membranes) A method for manufacturing the separation membrane 10 applicable to the air separation apparatus of this embodiment, as shown in Figures 2 and 3, will be described in detail. First, a porous alumina tube (average pore size: 1 μm, porosity: approximately 50%) is used as the support layer 7, and an intermediate layer 8 is formed on the surface of the support layer 7.

[0069] It is preferable to first homogenize the surface of the support layer 7 before forming the intermediate layer 8. For the material used for homogenization, it is preferable to use fine particles of the same material as the porous substrate used as the support layer 7. For example, if alumina is used as the porous substrate, it is preferable to support fine alumina particles of the same material on the surface of the porous substrate and homogenize them. The alumina nanoparticles can be supported on a porous substrate by using a sol of the same material as the material used to form the intermediate layer 8 (for example, a sol obtained from organoalkoxysilane) as a binder, dispersing the alumina nanoparticles in the binder, applying it to the surface of the porous substrate, drying, and firing. It is also preferable to homogenize the surface of the porous substrate by performing the above process multiple times, in which case it is preferable to gradually reduce the size of the alumina nanoparticles dispersed in the binder.

[0070] An intermediate layer 8 is formed on the homogenized support layer 7. The intermediate layer 8 is preferably formed by a hot coating method as follows. In the hot coating method, the porous substrate is preheated to about 170°C to 180°C, a dilute solution of a sol obtained from organoalkoxysilane is applied to the surface of the porous substrate, and the intermediate layer 8 is formed by firing. Note that the above process may be repeated multiple times to obtain an intermediate layer 8 of the desired thickness.

[0071] Next, an active separation layer 9 is formed on the surface of the intermediate layer 8. Specifically, the active separation layer 9 is formed by condensation polymerization of organoalkoxysilane using the sol-gel method. First, hydrochloric acid or nitric acid is added as an acid to an ethanol solution at 50°C with a water / silica ratio, and the mixture is stirred for about 1 hour. Then, to thin the resulting sol, it is coated onto the preheated intermediate layer and sintered. After that, it is fired at 300°C under a nitrogen atmosphere to obtain a gel in which siloxane bonds are replaced in the shaded areas (see Figure 4).

[0072] As described above, the separation membrane 10 applicable to the air separation apparatus of this embodiment, and the membrane module 1 using the same, have an intermediate layer 8 made of a hydrophobic material, and therefore exhibit excellent permeability characteristics similar to those at room temperature, even when used in a low-temperature environment such as the temperature range of the air separation apparatus (-196°C to 0°C). Therefore, the separation membrane 10 applicable to the air separation apparatus of this embodiment, and the membrane module 1 using the same, can maintain their membrane performance even at extremely low temperatures under which the air separation apparatus is operated.

[0073] <Air separation device> Next, we will describe the configuration of an air separation device, which is one embodiment to which the present invention is applied, using the case where it is applied to the membrane module 1 described above as an example. Figure 5 is a diagram showing an example of the configuration of an air separation device, which is one embodiment to which the present invention is applied.

[0074] As shown in Figure 5, the air separation apparatus 101 of this embodiment is generally configured to include a cold box (constant temperature bath) 20, a membrane module 1, a main heat exchanger 30, a raw material introduction path L1, a permeate component discharge path L2, and a non-permeate component discharge path L3. The air separation apparatus 101 of this embodiment separates arbitrary components from raw material air by membrane separation using the membrane module 1.

[0075] The cold box (constant temperature bath) 20 maintains a temperature inside the space to block external heat intrusion, allowing the air separation device to operate. The main heat exchanger 30 and the membrane module 1 are arranged inside the space inside the cold box 20.

[0076] The main heat exchanger 30 is located inside the cold box 20 and performs heat exchange between one or more hot fluids and one or more cold fluids, cooling the hot fluids and heating the cold fluids. In the air separation device 101 of this embodiment, the raw material introduction path L1 is the hot fluid, and the permeate component outlet path L2 and the non-permeate component outlet path L3 are the cold fluids, and heat exchange is performed between them. That is, the main heat exchanger 30 cools the raw material air flowing through the raw material introduction path L1 to a temperature near the dew point (for example, around -196 to -100°C). The main heat exchanger 30 may further include a thermal fluid and a cold fluid, which are not shown in the figures.

[0077] The membrane module 1 is located inside the cold box 20 and separates the introduced raw air into permeable components (hereinafter referred to as "permeable components") and non-permeable components (hereinafter referred to as "non-permeable components") by a separation section 3A having a separation membrane.

[0078] The raw material introduction path L1 is a channel for introducing the raw material gas to be separated into the membrane module 1. The raw material introduction path L1 is connected to the raw material introduction section 4 of the membrane module 1 (see Figure 1).

[0079] In the raw material introduction path L1, a compression block 40 that compresses the raw material air to the required pressure, a pretreatment block 50 that removes moisture and other impurities such as hydrocarbons from the raw material air, and a main heat exchanger 30 are arranged in this order. In other words, in the raw material air supply path, the membrane module 1 is located on the secondary side of the main heat exchanger 30. As a result, the raw material air, from which impurities have been removed and which has been heated and pressurized to the required temperature and pressure, is introduced into the membrane module 1.

[0080] The permeate component discharge path L2 is a channel for dischargeing components of the raw material gas introduced into the membrane module 1 that permeate through the separation section 3A, which has a separation membrane, from the membrane module 1. The permeate component discharge path L2 is connected to the permeate component discharge section 5 (see Figure 1) of the membrane module 1.

[0081] The non-permeable component discharge path L3 is a channel for dischargeing components of the raw material gas introduced into the membrane module 1 that do not permeate the separation section 3A, which has a separation membrane, from the membrane module 1. The non-permeable component discharge path L3 is connected to the non-permeable component discharge section 6 (see Figure 1) of the membrane module 1.

[0082] According to the air separation device 101 of this embodiment, the raw air introduced into the membrane module 1 is separated into a permeable component and an impermeable component by the separation unit 3A having a separation membrane, and each is discharged from the membrane module 1. The permeable component and the impermeable component discharged from the membrane module 1 are recovered as products after the cooling energy is recovered by the main heat exchanger 30.

[0083] Specifically, in the membrane module 1 used in the air separation device 101 of this embodiment, by using a separation membrane composed of a hydrophobic material having nanopores as the intermediate layer and the active separation layer, it is possible to separate, for example, raw air into oxygen and nitrogen.

[0084] (Variation 1) Next, a modified example 1 of an air separation device, which is one embodiment to which the present invention is applied, will be described. Figure 6 is a schematic diagram showing a modified configuration of an air separation device, which is one embodiment to which the present invention is applied.

[0085] As shown in Figure 6, the air separation apparatus 201 of Modification 1 of this embodiment is generally configured to include a cold box (constant temperature bath) 20, a membrane module 1, a main heat exchanger 30, a distillation column 60, a raw material introduction path L1, a permeate component discharge path L2, a non-permeate component discharge path L3, and a product discharge path L4. In other words, the air separation apparatus 201 of Modification 1 differs in configuration from the air separation apparatus 101 described above in that it includes a distillation column 60 on the secondary side of the membrane module 1. Therefore, the same reference numerals are used for the components shown in the air separation apparatus 101 described above, and their descriptions are omitted.

[0086] The distillation column 60 is located inside the cold box 20 and separates the raw material, which contains two or more air-based components, into low-boiling-point components and high-boiling-point components. The distillation column 60 is connected to a non-permeable component discharge route L3 and a product discharge route L4.

[0087] The non-permeable component extraction route L3 is located between the membrane module 1 and the distillation column 60 and is connected to any position in the distillation column 60. This allows the non-permeable component extracted from the membrane module 1 to be introduced into the distillation column 60 as a raw material.

[0088] The product extraction path L4 is connected to any position in the height of the distillation column 60. This allows components with a composition ratio corresponding to the position in the height of the distillation column 60 to be extracted as a product from the distillation column 60.

[0089] According to the air separation apparatus 201 of the modified example 1, the raw air introduced into the membrane module 1 is separated into a permeable component and an impermeable component by the separation unit 3A having a separation membrane, and each is discharged from the membrane module 1. The permeate components released from membrane module 1 are recovered as a product after the cooling energy is recovered by the main heat exchanger 30. The non-permeable components extracted from membrane module 1 are introduced into distillation column 60, where they are separated into low-boiling and high-boiling components, and then extracted via product extraction route L4. The components extracted from the distillation column 60 are recovered as a product or residue after the cooling energy is recovered by the main heat exchanger 30.

[0090] Specifically, in the membrane module 1 used in the air separation device 201 of Modified Example 1, by using a separation membrane composed of a hydrophobic material having nanopores as the intermediate layer and active separation layer, it is possible to separate the raw air into oxygen, which is a permeable component, and nitrogen and argon, which are impermeable components. In the distillation column 60, for example, nitrogen and argon can be easily separated.

[0091] (Modification 2) Next, a modified example 2 of an air separation device, which is one embodiment to which the present invention is applied, will be described. Figure 7 is a schematic diagram showing a modified configuration of an air separation device, which is one embodiment to which the present invention is applied.

[0092] As shown in Figure 7, the air separation apparatus 301 of Modification 2 of this embodiment is generally configured to include a cold box (constant temperature bath) 20, a membrane module 1, a main heat exchanger 30, distillation columns 60 and 70, a raw material introduction path L1, a permeate component discharge path L2, a non-permeate component discharge path L3, a product discharge path L4 and L6, and a raw material air introduction path L5. In other words, the air separation apparatus 301 of Modification 2 differs in configuration from the air separation apparatus 201 of Modification 1 described above in that it further includes a distillation column 70 on the primary side of the membrane module 1. Therefore, the same reference numerals are used for the components shown in the air separation apparatus 201 of Modification 1 described above, and their descriptions are omitted.

[0093] The distillation column 70 is located inside the cold box 20 and separates the raw material, which contains two or more air-based components, into low-boiling-point components and high-boiling-point components. The distillation column 70 is connected to a raw material air introduction path L5, a raw material introduction path L1, and a product discharge path L6.

[0094] The raw material air introduction path L5 is a flow path for introducing raw material air into the distillation column 70. The raw material air introduction path L5 is connected to any position in the height of the distillation column 70.

[0095] The raw material air introduction path L5 is configured in the following order: a compression block 40 that compresses the raw material air to the required pressure, a pretreatment block 50 that removes moisture and other impurities such as hydrocarbons from the raw material air, and a main heat exchanger 30. As a result, the raw material air, from which impurities have been removed and which has been heated and pressurized to the required temperature and pressure, is introduced into the distillation column 70.

[0096] The raw material introduction path L1 is located between the distillation column 70 and the membrane module 1 and is connected to any position in the height of the distillation column 70. This allows components with a composition ratio corresponding to the position in the height of the distillation column 70 to be introduced into the membrane module 1 as raw materials.

[0097] The product extraction route L6 is connected to the bottom or top of the distillation column 70 at a height corresponding to the column height. This allows components with a composition ratio corresponding to the position at the height of the distillation column 70 to be extracted as a product from the distillation column 70.

[0098] According to the air separation apparatus 301 of the modified example 2, the raw material air introduced into the distillation column 70 is separated into low-boiling point components and high-boiling point components, while the remaining air is introduced as raw material to the membrane module 1 via the raw material introduction path L1, which is withdrawn from any position in the distillation column 70. Furthermore, the components discharged from the distillation column 70 to the product discharge path L6 are recovered as product or residue after the cooling energy is recovered by the main heat exchanger 30. The raw material introduced into membrane module 1 is separated into permeable and non-permeable components by separation unit 3A, which has a separation membrane, and each is discharged from membrane module 1. The permeate components released from membrane module 1 are recovered as a product after the cooling energy is recovered by the main heat exchanger 30. The non-permeable components extracted from membrane module 1 are introduced into distillation column 60, where they are separated into low-boiling and high-boiling components, and then extracted via product extraction route L4. The components extracted from the distillation column 60 are recovered as a product or residue after the cooling energy is recovered by the main heat exchanger 30.

[0099] Specifically, in the membrane module 1 used in the air separation device 301 of Modified Example 2, by using a separation membrane composed of a hydrophobic material having nanopores as the intermediate layer and the active separation layer, it is possible to separate oxygen, which is the permeable component, and argon, which is the non-permeable component, from a raw material containing oxygen and argon. In the distillation column 70 located on the primary side of membrane module 1, nitrogen can be separated into oxygen and argon. In the distillation column 60 located on the secondary side of membrane module 1, argon and oxygen can be separated.

[0100] (Variation 3) Next, a third modified example of an air separation device, which is one embodiment to which the present invention is applied, will be described. Figure 8 is a schematic diagram showing a modified configuration of an air separation device, which is one embodiment to which the present invention is applied.

[0101] As shown in Figure 8, the air separation apparatus 401 of Modification 3 of this embodiment is generally configured to include a cold box (constant temperature bath) 20, a membrane module 1, a main heat exchanger 30, a distillation column 70, a raw material introduction path L1, a permeate component discharge path L2, a non-permeate component discharge path L3, and a raw material air introduction path L5. In other words, the air separation apparatus 401 of Modification 3 differs in configuration from the air separation apparatus 301 of Modification 2 described above in that it omits the distillation column 60 on the secondary side of the membrane module 1. Therefore, the same reference numerals are used for the components shown in the air separation apparatus 301 of Modification 2 described above, and their descriptions are omitted.

[0102] The distillation column 70 is located inside the cold box 20 and separates the raw material, which contains two or more air-based components, into low-boiling-point components and high-boiling-point components. The distillation column 70 is connected to the raw material air introduction path L5 and the raw material introduction path L1.

[0103] The raw material air introduction path L5 is a flow path for introducing raw material air into the distillation column 70. The raw material air introduction path L5 is connected to the bottom of the column height of the distillation column 70.

[0104] According to the air separation apparatus 401 of the modified example 3, the raw material air introduced into the distillation column 70 is separated into low-boiling point components and high-boiling point components, and a portion of it is introduced as raw material to the membrane module 1 via the raw material introduction path L1. The raw material introduced into membrane module 1 is separated into permeable and non-permeable components by separation unit 3A, which has a separation membrane, and each is discharged from membrane module 1. The permeate components released from membrane module 1 are recovered as a product after the cooling energy is recovered by the main heat exchanger 30. The non-permeable components released from membrane module 1 are recovered as a product or residue after the cooling energy is recovered by the main heat exchanger 30.

[0105] Specifically, in the membrane module 1 used in the air separation device 401 of Modification 3, by using a separation membrane composed of a hydrophobic material having nanopores as the intermediate layer and the active separation layer, it is possible to separate oxygen, which is the permeable component, and argon, which is the non-permeable component, from a raw material containing oxygen and argon. In the distillation column 70 located on the primary side of membrane module 1, nitrogen can be separated into oxygen and argon.

[0106] <Air separation method> Next, an air separation method, which is one embodiment to which the present invention is applied, will be described. The air separation method of this embodiment is performed using the air separation device 101 applied to the membrane module 1 described above. Specifically, the air separation method of this embodiment selectively separates a desired component from a mixed gas containing air components using a membrane module 1 including a separation membrane at a temperature near the dew point of the mixed gas containing air components. The air separation device 101 applied to the air separation method of this embodiment is merely an example and is not limited thereto. For example, the air separation devices 201, 301, and 401 described above may be applied to the air separation method of this embodiment.

[0107] As described above, according to the air separation apparatus 101 and air separation method of this embodiment, the membrane module 1 includes a separation membrane 10 having an intermediate layer 8 made of a hydrophobic material, and the membrane performance can be maintained even at extremely low temperatures in which the air separation apparatus is operated, so membrane separation can be used in low temperature environments (-196°C to 0°C). Therefore, since it is not a batch operation like adsorption, operating pressure and temperature swings are unnecessary.

[0108] Furthermore, according to the air separation apparatus 101 and air separation method of this embodiment, since membrane separation is applied, it is not subject to the constraints of gas-liquid equilibrium in distillation, and separation can be promoted in systems with a relative volatility close to 1 (e.g., argon / oxygen). In addition, since membrane separation is operated at a temperature near the dew point of the mixed gas, surface diffusion is likely to occur, which inhibits the diffusion of other components and can improve selectivity and permeability.

[0109] It should be noted that the technical scope of the present invention is not limited to the embodiments described above, and also includes designs and the like that do not depart from the spirit of the invention. For example, the air separation device 101 in the above-described embodiment is shown in a simplified manner and is not limited thereto.

[0110] Furthermore, while the air separation device 101 described above, and the air separation devices 201, 301, and 401 of the modified examples 1 to 3, were described as having one main heat exchanger 30, they may also have two or more heat exchangers. Also, in the air separation device 101 described above, the membrane module 1 is located on the secondary side of the main heat exchanger 30, but the membrane module 1 may also be located on the secondary side of other heat exchangers.

[0111] Furthermore, while the air separation apparatus 101 described above, and the air separation apparatuses 201, 301, and 401 of the modified examples 1 to 3, were described as having one distillation column on the primary or secondary side of the membrane module 1, the configuration is not limited to this. For example, the membrane module 1 may have two or more distillation columns on the primary or secondary side. [Examples]

[0112] The present invention will be specifically described below with reference to examples, but the present invention is not limited to the following description.

[0113] <Example 1> A separation unit (separation membrane) with the configuration shown in Figure 2 was created under the following conditions, and the temperature dependence of the air system components in the temperature range from room temperature to -30°C was evaluated.

[0114] (Materials used) • Support section: Non-perforated alumina tube (length 200 mm) • Support layer: Porous alumina tube (Outer diameter: 10 mm, Length: 100 mm, Average pore size: 1 μm, Porosity: approx. 50%) • Intermediate layer: BTESE gel is supported as a hydrophobic material (thickness: 200-300 nm) • Active separation layer: Supported with BTESP polymer gel (thickness: 50-100 nm)

[0115] (Preparation ratio) ·Middle layer ···BTESE:H2O:HCl=1:240:0.1 ·Active separation layer ··BTESP:H2O:HCl=1:200:0.1

[0116] (Film forming method) After supporting a support layer (α-Al2O3) with fine particles of Al2O3 dissolved in water, the material was fired at 300°C for 15 minutes in an N2 atmosphere. This process was repeated several times. As an intermediate layer, the BTESE sol prepared according to the above ratio was applied to a preheated support layer and sintered to support it. Then, it was fired at 300°C under an N2 atmosphere. This process was repeated several times. As the active separation layer, the BTESP sol prepared according to the above ratio was coated onto a preheated support layer and sintered to support it. Then, it was fired at 300°C under an N2 atmosphere. This process was repeated several times. The fabricated separation membrane was placed inside a membrane module and fired again at 300°C.

[0117] (evaluation) Various pure gases were supplied to the prepared separation unit (separation membrane) under the following conditions, and the permeance of each gas was measured. The results are shown in Figure 9. • Gas types: Hydrogen (H2), Helium (He), Oxygen (O2), Argon (Ar), Nitrogen (N2) • Gas temperature: -30 to 200°C • Flow rate through the membrane: 1 L / min • Outer surface area of ​​the membrane: 3.14 × 10 -3 m 2 Primary pressure: 200 kPaG Secondary pressure: atmospheric pressure

[0118] Figure 9 shows the temperature dependence of the permeance when various gases permeate the separation unit (separation membrane) of Example 1. In Figure 9, the first X-axis (bottom) represents the reciprocal of the operating temperature [K] multiplied by 1000, the second X-axis (top) represents the gas temperature, and the Y-axis represents the permeance. As shown in Figure 9, the separation unit (separation membrane) of Example 1 uses a layer made of a hydrophobic material as an intermediate layer, and it was confirmed that the permeability of various gases falls on the extrapolation line at room temperature. In other words, it was confirmed that the membrane performance is maintained even at -30°C by using a hydrophobic material for the intermediate layer of the separation membrane.

[0119] <Comparative Example 1> Similar to Example 1, a separation unit (separation membrane) was prepared, and the temperature dependence of the air system components in a temperature range from room temperature to -30°C was evaluated.

[0120] (Materials used) Except for changing the intermediate layer, the procedure was the same as in Example 1. • Intermediate layer: Gel using SiO2-ZrO2 is supported (thickness: 200-300 nm)

[0121] (Film forming method) Except for the intermediate layer, the procedure was the same as in Example 1. To prepare the SiO2-ZrO2 colloidal sol, first, ethanol was added to a 500 ml flask, and the Si precursor TEOS, water, and the acid catalyst hydrochloric acid were added and stirred at room temperature for 3 hours. Next, the Zr precursor ZrTBt, water, and hydrochloric acid were added and stirred for 12 hours. After stirring, more water and hydrochloric acid were added and stirred at room temperature for 10 minutes. Then, to control the particle size, a predetermined amount of hydrochloric acid was added, and water was added up to the 500 ml mark. Finally, by boiling and stirring (200°C) for 8 hours, an SiO2-ZrO2 colloidal sol with a particle size of 20-30 nm was obtained. As an intermediate layer, the obtained SiO2-ZrO2 colloidal sol was coated onto a preheated support layer and sintered to support it. Then, it was fired at 350°C under an N2 atmosphere. This process was repeated several times.

[0122] (evaluation) The permeance of various gases was measured when they permeated the fabricated separation unit (separation membrane) under the following conditions. The results are shown in Figure 10. • Gas types: Hydrogen (H2), Helium (He), Argon (Ar), Nitrogen (N2) • Gas temperature: -30 to 200°C • Molar flow rate permeating the membrane: 1 L / min • Outer surface area of ​​the membrane: 3.14 × 10 -3 m 2 Primary pressure: 200 kPaG Secondary pressure: atmospheric pressure

[0123] Figure 10 shows the temperature dependence of the permeance when various gases permeate the separation unit (separation membrane) of Comparative Example 1. In Figure 6, the first X-axis (bottom) represents the reciprocal of the operating temperature [K] multiplied by 1000, the second X-axis (top) represents the gas temperature, and the Y-axis represents the permeance. As shown in Figure 10, the separation unit (separation membrane) of Comparative Example 1 uses a layer made of "SiO2-ZrO2" as an intermediate layer, and it was confirmed that the permeability of all gases decreased significantly at temperatures below 10°C. In other words, it was confirmed that using a hydrophilic material for the intermediate layer of the separation membrane causes the membrane to be affected by water vapor remaining on the membrane surface or in the supplied gas, resulting in a decrease in membrane performance under low-temperature conditions.

[0124] <Example 2> A separation unit (separation membrane) with the configuration shown in Figure 2 was created under the following conditions, and the temperature dependence of the air system components in the temperature range from room temperature to -115°C was evaluated.

[0125] (Materials used) • Support section: Non-perforated alumina tube (length 200 mm) • Support layer: Porous alumina tube (Outer diameter: 10 mm, Length: 100 mm, Average pore size: 1 μm, Porosity: approx. 50%) • Intermediate layer: BTESE gel is supported as a hydrophobic material (thickness: 200-300 nm) ·Active separation layer: Carrying BTESM gel (thickness: 50 - 100 nm)

[0126] (Preparation ratio) ·Intermediate layer ··· BTESE:H2O:HCl = 1:240:0.1 ·Active separation layer ··· BTESM:H2O:HCl = 1:200:0.1

[0127] (Film - forming method) Fine particles of Al2O3 dissolved in water were carried on the support layer (α - Al2O3), and then calcined at 300 °C for 15 minutes in a N2 atmosphere. This was repeated several times. As the intermediate layer, the BTESE sol prepared in the above - mentioned preparation ratio was applied onto the pre - heated support layer and sintered and carried by coating. Then, it was calcined under the condition of 300 °C in a N2 atmosphere. This was repeated several times. As the active separation layer, the BTESM sol prepared in the above - mentioned preparation ratio was applied onto the pre - heated support layer and sintered and carried by coating. Then, it was calcined under the condition of 300 °C in a N2 atmosphere. This was repeated several times. The prepared separation membrane was stored in a membrane module and calcined again at 300 °C.

[0128] (Evaluation) The permeance when various gases permeated through the prepared separation unit (separation membrane) was measured under the following conditions. The results are shown in Figure 11. ·Gas species: Hydrogen (H2), Helium (He), Oxygen (O2), Argon (Ar), Nitrogen (N2) ·Gas temperature: - 115 - 200 °C ·Molar flow rate permeating through the membrane: 1 L / min ·Outer surface area of the membrane: 3.14×10 -3 m 2 ·Primary - side pressure: 200 kPaG ·Secondary - side pressure: Atmospheric pressure

[0129] Figure 11 shows the temperature dependence of the permeance when various gases permeate the separation unit (separation membrane) of Example 2. In Figure 11, the first X-axis (bottom) represents the reciprocal of the operating temperature [K] multiplied by 1000, the second X-axis (top) represents the gas temperature, and the Y-axis represents the permeance. As shown in Figure 11, the separation unit (separation membrane) of Example 2 was found to maintain its membrane performance even at -115°C because the intermediate layer of the separation membrane is made of a hydrophobic material. [Explanation of symbols]

[0130] 1…Membrane module 2…Membrane module body 2A…Space 3…Separation Unit 3A…Separation part 3B…Support part 4...Raw material introduction section 5...Transmission component derivation section 6...Non-transparent component derivation section 7…Support layer 8…Middle class 9…Active separation layer 10...Separation membrane 20…Cold box (constant temperature bath) 30…Main heat exchanger 40... Compressed Blocks 50…Preprocessing block 60, 70… distillation columns 101, 201, 301, 401… Air separation devices L1…Raw material introduction route L2...Transmitted component derivation pathway L3... Derivation path for non-permeable components L4, L6…Product Derivation Path L5…Raw air introduction path

Claims

1. The inner space is enclosed by a constant temperature chamber to block heat from entering from the outside, The system comprises a membrane module located in the aforementioned space, The membrane module has a separation membrane on a support layer made of a porous substrate, The separation membrane selectively separates any component from a mixed gas containing air components at a temperature near the dew point of the mixed gas containing air components. The separation membrane is a laminated film consisting of an active separation layer and an intermediate layer formed from a compound having siloxane bonds. The active separation layer is a gel formed by calcining a sol prepared from organoalkoxysilane. The sol prepared from the organoalkoxysilane is one or more precursors selected from 1,2-bis(triethoxysilyl)methane, 1,2-bis(triethoxysilyl)ethane, 1,2-bis(triethoxysilyl)propane, and 1,2-bis(triethoxysilyl)benzene, and one or more sols obtained from their hydrolysates. An air separation apparatus in which the temperature near the dew point is -196°C or higher and less than 0°C.

2. A membrane module body in which a separation section having the separation membrane is located in the inner space, A raw material introduction unit for introducing the raw material containing the aforementioned air-based components into the membrane module body, A permeation component discharge unit discharges the component that permeates through the separation unit from the main body of the membrane module, The air separation apparatus according to claim 1, further comprising: a non-permeable component discharge unit for dischargeing components that do not permeate the separation unit from the membrane module body.

3. The air separation device according to claim 1, wherein the support layer is hollow cylindrical.

4. The air separation apparatus according to claim 1, wherein the dew point of the moisture contained in the mixed gas containing the air-based components is -50°C or lower.

5. Further comprising a main heat exchanger for cooling the mixed gas containing the air-based components to a temperature near the dew point, The air separation apparatus according to claim 1, wherein the membrane module is located on the secondary side of the main heat exchanger.

6. The facility further includes one or more distillation columns, The non-permeable component outlet is connected to the distillation column, The air separation apparatus according to claim 2, wherein the distillation column distills the components introduced from the non-permeable component outlet.

7. An air separation method using an air separation device, The aforementioned air separation device comprises a constant temperature chamber to block heat intrusion from the outside, within its internal space. The system comprises a membrane module located in the aforementioned space, The membrane module has a separation membrane on a support layer made of a porous substrate, The separation membrane is a laminated film consisting of an active separation layer and an intermediate layer formed from a compound having siloxane bonds. The active separation layer is a gel formed by calcining a sol prepared from organoalkoxysilane. The sol prepared from the organoalkoxysilane is one or more precursors selected from 1,2-bis(triethoxysilyl)methane, 1,2-bis(triethoxysilyl)ethane, 1,2-bis(triethoxysilyl)propane, and 1,2-bis(triethoxysilyl)benzene, and one or more sols obtained from their hydrolysates. At a temperature near the dew point of a mixed gas containing air-based components, the separation membrane selectively separates any component from the mixed gas containing air-based components. An air separation method wherein the temperature near the dew point is -196°C or higher and less than 0°C.

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