Gas separation device

Abstract

The present invention provides a gas separation device in which gas separation membrane modules are arranged at a high density while suppressing an increase in weight of the gas separation device, and which has excellent maintainability of the gas separation membrane modules. A gas separation device according to one embodiment of the present invention comprises: at least one array that includes a plurality of gas separation membrane modules which are connected in series; and at least one support part that supports the at least one array. Each of the plurality of gas separation membrane modules includes a cylindrical housing that has flange parts at both ends, and at least one inorganic membrane element that is housed in the cylindrical housing. The plurality of gas separation membrane modules are connected by butting and fixing the flange parts of cylindrical housings against each other. The support part supports the at least one array such that the longitudinal direction of the at least one array extends along the lengthwise direction of the gas separation device.

Description

Gas separation device

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

[0002] Gas separation membranes are used as a pretreatment to separate non-hydrocarbon gases such as carbon dioxide and nitrogen contained in natural gas and associated gases of crude oil. In the separation process, non-hydrocarbons permeate the gas separation membrane and are separated from hydrocarbons that do not permeate the membrane. As an example of a gas separation membrane, a zeolite membrane deposited on a porous support is known.

[0003] Patent Document 1 (International Publication No. 2017 / 056134) describes a non-hydrocarbon gas separation apparatus for separating non-hydrocarbon gases from natural gas containing non-hydrocarbon gases, comprising: a supply line to which natural gas containing heavy hydrocarbons having 5 or more carbon atoms is supplied; an outlet line from which natural gas separated from the non-hydrocarbon gases flows out; and an outlet line from which non-hydrocarbon gases separated from the natural gas are discharged; a separation module connected to these lines; an inorganic membrane made of an inorganic material housed within the separation module, which allows non-hydrocarbon gases contained in the natural gas supplied from the supply line to permeate to the outlet line side and allows the natural gas from which the non-hydrocarbon gases have been separated to flow to the outlet line side; and a heating unit disposed on the supply line side for heating the natural gas, wherein the heating unit heats the natural gas supplied to the separation module in response to the temperature drop caused by the permeation of the inorganic membrane by the non-hydrocarbon gases, so that the temperature inside the separation module is maintained at a temperature higher than the dew point temperature of the heavy hydrocarbons.

[0004] Patent Document 2 (International Publication No. 2017 / 056135) describes a non-hydrocarbon gas separation apparatus for separating non-hydrocarbon gases from natural gas containing non-hydrocarbon gases, comprising: a first separation module and a second separation module, each connected to a supply line for which the natural gas is supplied, an outlet line for which the natural gas separated from the non-hydrocarbon gases flows out, and an outlet line for which the non-hydrocarbon gases separated from the natural gas are discharged; and a separation membrane, each housed within the first and second separation modules, for allowing the non-hydrocarbon gases contained in the natural gas supplied from the supply line to permeate to the outlet line side and for allowing the natural gas from which the non-hydrocarbon gases have been separated to flow to the outlet line side, wherein the outlet line of the first separation module and the supply line of the second separation module are common, the first and second separation modules are connected in series, and the pressure on the outlet line side within the first separation module is higher than the pressure on the outlet line side within the second separation module.

[0005] International Publication No. 2017 / 056134, International Publication No. 2017 / 056135

[0006] There is a strong demand for operating gas separation equipment not only on land but also at sea. At sea, gas separation equipment is installed on a floating structure with a ship-like hull. Since the installation area for gas separation equipment on a floating structure is limited, it is desirable to arrange the gas separation membrane modules at high density within the gas separation equipment from the perspective of efficient use of installation area. On the other hand, in order to reduce the load on the floating structure, it is desirable for the gas separation equipment to be lightweight.

[0007] Compared to organic polymer separation membranes, inorganic separation membranes tend to be heavier. Therefore, inorganic separation membranes often present maintenance difficulties in terms of weight or size. In particular, maintenance work on floating structures far from land is challenging due to limited personnel and constraints on the acquisition, storage, and movement of maintenance materials and supplies. Therefore, it is desirable to simplify the maintenance of gas separation equipment.

[0008] This disclosure provides a gas separation apparatus in which gas separation membrane modules are arranged at high density while suppressing an increase in the weight of the gas separation apparatus, and which offers excellent maintainability of the gas separation membrane modules.

[0009] The inventors have found that by fixing the flange portions of multiple gas separation membrane modules together, an array is formed in which multiple gas separation membrane modules are connected in series, and by arranging the array so that its longitudinal direction extends along the longitudinal direction of the gas separation device, it is possible to arrange the gas separation membrane modules at high density while suppressing an increase in the weight of the gas separation device, and also improve the maintainability of the gas separation membrane modules.

[0010] This disclosure encompasses the following embodiments: [Embodiment 1] A gas separation apparatus comprising: at least one array including a plurality of gas separation membrane modules connected in series; and at least one support portion supporting the at least one array, wherein each of the plurality of gas separation membrane modules includes a cylindrical housing having flanges at both ends and at least one inorganic membrane element housed within the cylindrical housing; the plurality of gas separation membrane modules are connected by fixing the flanges of the cylindrical housings together; and the support portion supports the at least one array such that its longitudinal direction extends along the longitudinal direction of the gas separation apparatus. [Embodiment 2] The gas separation apparatus according to Embodiment 1, wherein the cylindrical housing includes a gas supply port, a permeable gas outlet, and a non-permeable gas outlet, and the plurality of gas separation membrane modules are connected such that the non-permeable gas outlet and the gas supply port are in gas communication. [Embodiment 3] The gas separation apparatus according to Embodiment 1 or 2, wherein the at least one inorganic membrane element includes a DDR type zeolite membrane. [Aspect 4] The gas separation apparatus according to any one of aspects 1 to 3, wherein the at least one inorganic membrane element housed in the cylindrical housing is two inorganic membrane elements connected in series. [Aspect 5] The gas separation apparatus according to any one of aspects 1 to 4, further comprising a regeneration mechanism for regenerating the at least one inorganic membrane element. [Aspect 6] The gas separation apparatus according to any one of aspects 1 to 5, further comprising a centering mechanism for maintaining the longitudinal direction of the at least one array to extend along the longitudinal direction of the gas separation apparatus.

[0011] According to this disclosure, it is possible to provide a gas separation apparatus in which gas separation membrane modules are arranged at high density while suppressing an increase in the weight of the gas separation apparatus, and which also offers excellent maintainability of the gas separation membrane modules.

[0012] The above description should not be considered to disclose all embodiments of the present invention or all advantages relating to the present invention.

[0013] This is a schematic side view of a gas separation apparatus according to one embodiment. This is a schematic cross-sectional view of an array according to one embodiment. This is a schematic cross-sectional view of a gas separation membrane module according to one embodiment. This is a schematic cross-sectional view of two inorganic membrane elements connected by a first connecting jig. This is a schematic perspective view of an inorganic membrane element according to one embodiment.

[0014] The present invention will be described in more detail below with reference to the drawings to illustrate typical embodiments, but the present invention is not limited to these embodiments.

[0015] [Gas Separation Apparatus] A gas separation apparatus according to one embodiment comprises at least one array including a plurality of gas separation membrane modules connected in series, and at least one support portion supporting the at least one array. Each of the plurality of gas separation membrane modules includes a cylindrical housing having flanges at both ends, and at least one inorganic membrane element housed within the cylindrical housing. The plurality of gas separation membrane modules are connected by fixing the flanges of the cylindrical housings together. The support portion supports the at least one array such that its longitudinal direction extends along the longitudinal direction of the gas separation apparatus.

[0016] By connecting multiple gas separation membrane modules by butting and fixing the flange portions of the cylindrical housings together, the weight of the array can be reduced without using components commonly used to connect gas separation membrane modules, such as caps. The flange portions, which have the mechanical strength necessary to connect gas separation membrane modules, tend to be heavy. However, by avoiding the use of other components such as caps for connecting gas separation membrane modules, the overall weight of the gas separation apparatus can be reduced even if the weight of the flange portions increases, thereby achieving space savings and material reduction between gas separation membrane modules. In addition, because there are fewer connection points between gas separation membrane modules, the man-hours and time required for maintenance work can be reduced.

[0017] The support structure supports the array so that its longitudinal direction aligns with the vertical direction of the gas separation device. In other words, by arranging the array vertically, the vertical space can be effectively utilized, allowing for a high-density arrangement of gas separation membrane modules within the gas separation device. Vertical arrangement of the array also increases the flexibility of the planar layout of the gas separation membrane modules, thereby easily ensuring the necessary access routes for maintenance work.

[0018] The vertically positioned array can be easily lifted by workers using hand jacks or similar equipment. While the array is being lifted, the gas separation membrane modules can be removed one by one and moved to a location separate from the array's installation site, allowing for maintenance work on the gas separation membrane modules, such as replacement or regeneration. This reduces the maintenance space required at the array's installation site.

[0019] By orienting the array vertically, the clamping pressure at the flange portion of the gas separation membrane module can be made more uniform, reducing localized gas leakage from the connection points of the gas separation membrane module. Orienting the array vertically also prevents deformation or bending of the housing due to its own weight, even when using a long housing, thus reducing gas leakage from the sealing points inside the housing.

[0020] Figure 1 shows a schematic side view of a gas separation apparatus according to one embodiment. The gas separation apparatus 10 comprises an array 11 containing four gas separation membrane modules 20 connected in series, and a support section 12 that supports the array 11. Figure 1 shows the four arrays 11 and the two support sections 12 that support each array 11. At the lower support section of the two support sections 12, the array 11 is inserted into a guide and fixed, while at the upper support section, the array 11 is loosely held to prevent excessive horizontal displacement of the array 11. The upper support section is shown as part of the deck of the gas separation apparatus 10, allowing an operator to lift the array 11 from the deck. The lower end of each array 11 is connected via caps and piping to establish gas communication with the lower end of an adjacent array 11. The upper end of each array 11 is connected to either the gas to be processed supply side or the non-permeable gas discharge side.

[0021] Arrow V shown in Figure 1 Ｄ This is the vertical direction of the gas separator. In this disclosure, the vertical direction of the gas separator is defined as the direction ± 5 degrees from the vertical, preferably ± 2 degrees from the vertical, when the gas separator is placed on a horizontal plane in a stationary state.

[0022] <Array> An array includes multiple gas separation membrane modules connected in series. The number of gas separation membrane modules in one array can be appropriately determined considering the vertical dimensions of the gas separation apparatus, the length and weight of the gas separation membrane modules, etc., and may be two, three, four, or more. From the viewpoint of ease of lifting the array, it is preferable that the weight of the array is such that it can be lifted with a hand jack. For example, the number of gas separation membrane modules can be determined so that the weight of one array is 2 tons or less, preferably 1 ton or less.

[0023] The number of arrays included in the gas separation device can be appropriately determined considering the processing capacity, installation area, weight, etc., and may be one, two, three, or more, for example, 24, 48, or 96. Multiple arrays may be connected to each other to allow gas communication.

[0024] Figure 2 shows a schematic cross-sectional view of an array according to one embodiment. The array 11 includes two gas separation membrane modules 20 connected in series. Arrow L in Figure 2 Ｄ This is the longitudinal direction of the array.

[0025] <Support Section> The support section supports the array so that its longitudinal direction extends along the longitudinal direction of the gas separator. The material constituting the support section is not particularly limited, but examples include carbon steel and stainless steel. The support section may fix the array to prevent it from moving, or it may hold the array to prevent excessive displacement. The number of support sections included in the gas separator can be appropriately set considering the length and weight of the array, and may be one, two, three, or more per array. It is preferable to have two or more support sections for one array to distribute the load on the array and the support sections.

[0026] The support section may be part of the deck of the gas separator. The gas separator may have a multi-story structure, with the array penetrating the decks of each floor, and support sections provided on the decks of each floor.

[0027] <Gas Separation Membrane Module> The gas separation membrane module includes a cylindrical housing having flanges at both ends and at least one inorganic membrane element housed within the cylindrical housing. The number of inorganic membrane elements housed in the cylindrical housing can be appropriately determined considering gas separation efficiency, maintainability, etc., and may be one, two, three, or more, with one, two, or three being preferred.

[0028] Figure 3 shows a schematic cross-sectional view of a gas separation membrane module according to one embodiment. The gas separation membrane module 20 includes a cylindrical housing 21. The cylindrical housing 21 has flange portions 211 at both ends. The material of the cylindrical housing 21 is not particularly limited, but stainless steel is preferred from the viewpoint of corrosion resistance and durability. The thickness of the cylindrical housing 21 is not particularly limited, but for example, it can be thick enough to hold a fluid with a pressure of 1 to 15 MPaA. As shown in Figure 2, the flange portions 211 have a shape and strength suitable for fixing the gas separation membrane modules 20 together.

[0029] As shown in Figure 2, the two gas separation membrane modules 20 are connected by butting and fixing the flange portions 211 of the cylindrical housing 21 together. The flange portions 211 can be fixed together with fasteners 27. The fasteners 27 are not particularly limited, but examples include bolts and nuts. The flange portions may have holes for passing fasteners such as bolts. A sealing material such as a gasket may be placed between the abutting surfaces of the flange portions 211.

[0030] In one embodiment, as shown in Figures 2 and 3, the cylindrical housing 21 includes a gas supply port 212, a permeable gas outlet 213, and a non-permeable gas outlet 214. The cylindrical housing 21 may further include a regeneration fluid inlet 215 into which a fluid for regenerating used inorganic membrane elements is introduced, as shown in Figures 2 and 3. Instead of the regeneration fluid inlet 215, the regeneration fluid can also be introduced using the gas supply port 212, the permeable gas outlet 213, or the non-permeable gas outlet 214. As shown in Figure 2, it is preferable that a plurality of gas separation membrane modules 20 are connected such that the non-permeable gas outlet 214 of one gas separation membrane module 20 is in gas communication with the gas supply port 212 of the other gas separation membrane module 20.

[0031] As shown in Figure 3, when a gas to be treated G containing multiple gaseous components is supplied to the gas to be treated supply port 212, some of the components contained in the gas to be treated G permeate through an inorganic membrane element (not shown) housed inside the perforated housing 23 and are concentrated and removed as permeate gas P from the permeate gas outlet 213, while the remaining components do not permeate through the inorganic membrane element and are concentrated and removed as impermeable gas NP from the impermeable gas outlet 214. In this way, the gas to be treated G can be separated into permeate gas P and impermeable gas NP. The regeneration fluid inlet 215 is closed during the separation of the gas to be treated G.

[0032] In Figures 2 and 3, the inorganic film element is housed inside the perforated housing 23. By housing the inorganic film element inside the perforated housing 23, damage or breakage of the inorganic film element during high-pressure gas separation processing can be prevented or suppressed. The material of the perforated housing 23 is not particularly limited, but stainless steel is preferred from the viewpoint of corrosion resistance and durability.

[0033] In Figures 2 and 3, two perforated housings 23, each housing an inorganic film element, are connected in series at one end via a first connecting jig 25. Thus, the two inorganic film elements are connected in series and housed in the cylindrical housing 21. A second connecting jig 26 is provided at the end of the perforated housing 23 opposite to the first connecting jig 25, and a seal 24 positioned on the outer surface of the second connecting jig 26 hermetically separates the gas supply port 212 and the non-permeable gas outlet 214 from the permeable gas outlet 213. As the seal 24, for example, an O-ring or sheet-shaped packing containing an elastic material such as rubber or silicone resin can be used.

[0034] Figure 4 shows a schematic cross-sectional view of two inorganic film elements connected in series by a first connecting jig. The inorganic film element 22 is housed inside a perforated housing 23. At one end of the inorganic film element 22, a seal 24 is positioned between the surface of the inorganic film element 22 on the gas supply side or the non-permeable gas discharge side and the inner surface of the first connecting jig 25. At the other end of the inorganic film element 22, a seal 24 is positioned between the outer surface of the inorganic film element 22 and the inner surface of the perforated housing 23, and between the outer surface of the perforated housing 23 and the inner surface of the second connecting jig 26. As the seal 24, for example, an O-ring or sheet-shaped packing containing an elastic material such as rubber or silicone resin can be used.

[0035] <Inorganic film element> The inorganic film element is not particularly limited, but for example, one in which a gas separation membrane is deposited on a porous support can be used.

[0036] The shape of the inorganic membrane element may be either cylindrical or rectangular. The inorganic membrane element may be a single tube or may have a honeycomb shape with a plurality of cells. In the case of a single tube inorganic membrane element, a gas separation membrane can be formed on the inner surface, outer surface, or both surfaces of the inorganic membrane element. The honeycomb-shaped inorganic membrane element includes a honeycomb-shaped porous support having a plurality of cells separated by porous partitions extending from one end face in the longitudinal direction to the other end face, and a gas separation membrane is formed on the inner wall of each cell. A gas separation membrane may be further formed on the outer surface of the porous support. The cross-sectional shape of the cell can be circular, elliptical, or polygonal.

[0037] Fig. 5 shows a schematic perspective view of an inorganic membrane element according to an embodiment. The inorganic membrane element 22 includes a cylindrical porous support 222 and a number of cells 221 penetrating therethrough. A gas separation membrane (not shown) is formed on the inner wall of the cell 221.

[0038] Examples of the porous support include ceramics such as silica, α-alumina, γ-alumina, mullite, zirconia, titania, yttria, cordierite, silicon nitride, and silicon carbide, porous glasses such as shirasu porous glass, and porous sintered metals such as stainless steel. When the gas separation membrane is a zeolite membrane, ceramics containing at least one selected from the group consisting of alumina, silica, and mullite are preferred. Since ceramics containing at least one selected from the group consisting of alumina, silica, and mullite strongly bond to the zeolite membrane, a dense and highly separation-performance inorganic membrane element can be formed. The porous support preferably contains alumina because of its high corrosion resistance.

[0039] The average pore diameter of the porous support can be 10 nm to 10 μm, preferably 50 nm to 5 μm, more preferably 100 nm to 3 μm. By setting the average pore diameter of the porous support to 10 nm or more, the gas transport resistance can be reduced and the permeability of gas molecules can be improved. By setting the average pore diameter of the porous support to 10 μm or less, the generation of defects or cracks in the gas separation membrane can be reduced. The average pore diameter of the porous support is determined by the gas adsorption method.

[0040] In one embodiment, the inorganic membrane element includes at least one selected from the group consisting of a zeolite membrane, a silica membrane, and a carbon membrane as the gas separation membrane.

[0041] Examples of the zeolite membrane include zeolite membranes having a crystal structure of 8-member ring zeolites such as DDR, LTA, CHA, ERI, AEI, and RHO, 10-member ring zeolites such as MFI and FER, and 12-member ring zeolites such as MOR, FAU, and BEA.

[0042] Examples of the silica membrane include porous silica membranes formed from a silica source containing at least one of tetraalkoxysilanes such as tetramethoxysilane and tetraethoxysilane; trialkoxysilanes such as ethyltrimethoxysilane, methyltrimethoxysilane, n-octyltriethoxysilane, and n-decyltrimethoxysilane; hexamethyldisiloxane; hexamethyldisilazane; cyclic siloxanes such as octamethylcyclotetrasiloxane and decamethylcyclopentasiloxane; or a combination of two or more thereof.

[0043] Examples of the carbon membrane include porous carbon membranes formed from a raw material containing at least one polymer selected from the group consisting of phenol resin, melamine resin, epoxy resin, cellulose acetate, polyimide, polyamide, polyaramide, polyketone, polyether ketone, polypropylene oxide, polyphenylene oxide, and derivatives thereof.

[0044] At least one inorganic membrane element preferably includes a DDR-type zeolite membrane. The DDR-type zeolite membrane permeates the gas CO ２This allows for advantageous use in separation processes where the non-permeable gas is converted into a hydrocarbon gas, particularly methane.

[0045] The average pore size of the gas separation membrane can be 0.01 nm to 20 nm, preferably 0.05 nm to 10 nm, and more preferably 0.1 nm to 1 nm. By setting the average pore size of the gas separation membrane to 0.01 nm or more, the permeability of gas molecules can be improved. By setting the average pore size of the gas separation membrane to 20 nm or less, the selective permeability, which allows specific gas molecules to pass through more selectively than other gas molecules, can be improved. The average pore size of the gas separation membrane is determined by capillary condensation.

[0046] The gas separation membrane may be single-layered or multi-layered. In the case of a multi-layered gas separation membrane, it is preferable that the average pore diameter of each layer is designed such that the average pore diameter increases from the surface in contact with the gas to be treated towards the porous support.

[0047] The thickness of the gas separation membrane can be 1 nm to 100 μm, preferably 10 nm to 50 μm, and more preferably 50 nm to 5 μm. By setting the thickness of the gas separation membrane to 1 nm or more, uniform separation performance can be provided to the entire inorganic membrane element. By setting the thickness of the gas separation membrane to 100 μm or less, the permeation pressure loss can be reduced, and crack generation due to the difference in thermal expansion between the gas separation membrane and the porous support can be suppressed. When the gas separation membrane is multilayered, the thickness of the gas separation membrane is the sum of the thicknesses of each layer.

[0048] The formation of porous supports and the deposition of gas separation membranes can be carried out by conventionally known methods. Zeolite membranes can be formed, for example, by hydrothermal synthesis using a precursor sol of the gas separation membrane and, if necessary, a seed crystal of the gas separation membrane, followed by a heat treatment or calcination treatment. Silica membranes can be formed, for example, by coating with a silica sol, which is a hydrolysate of tetraethoxylan, and then by a calcination treatment. Carbon membranes can be formed, for example, by coating with a solution containing polymers such as phenolic resin, melamine resin, polyimide, and epoxy resin, and then by a carbonization treatment.

[0049] <Regeneration Mechanism> The gas separation device preferably further comprises a regeneration mechanism for regenerating at least one inorganic membrane element. The regeneration mechanism is not particularly limited, but an example is one that supplies regenerating fluid to the regeneration fluid inlet 215 shown in Figures 2 and 3.

[0050] <Centering Mechanism> A gas separation apparatus of one embodiment further comprises a centering mechanism (not shown) that maintains the longitudinal direction of at least one array so as to extend along the longitudinal direction of the gas separation apparatus. The gas separation apparatus of this embodiment can be advantageously installed on a floating body that experiences motion at sea.

[0051] [Gas Separation Treatment] Examples of gases to be treated supplied to the gas separation apparatus include mixed gases of one or more hydrocarbons and inorganic gases, mixed gases of one or more hydrocarbons and water, and mixed gases of two or more hydrocarbons. Both the adsorption properties to the gas separation membrane contained in the inorganic membrane element and the diffusivity within the pores of the gas separation membrane affect the permeability of each component contained in the gas to be treated to the inorganic membrane element. Therefore, whether or not the components contained in these mixed gases permeate the inorganic membrane element depends on the constituent components and pore size of the gas separation membrane, as well as the chemical affinity and dynamic molecular diameter of the components contained in the mixed gas.

[0052] Examples of hydrocarbons include linear hydrocarbons having 1 to 8 carbon atoms, branched hydrocarbons having 4 to 8 carbon atoms, and cyclic hydrocarbons having 3 to 8 carbon atoms. Examples of linear hydrocarbons having 1 to 8 carbon atoms include saturated linear hydrocarbons selected from the group consisting of methane, ethane, n - propane, n - butane, n - pentane, n - hexane, n - heptane, and n - octane, and unsaturated linear hydrocarbons such as ethylene, propylene, 1 - butene, 2 - butene, butadiene, 1 - pentene, 2 - pentene, 1,3 - pentadiene, and acetylene. Examples of branched hydrocarbons having 4 to 8 carbon atoms include saturated branched hydrocarbons such as isobutane and isopentane, and unsaturated branched hydrocarbons such as isobutene, 2 - methyl - 1 - butene, 2 - methyl - 2 - butene, 3 - methyl - 1 - butene, and isoprene. Examples of cyclic hydrocarbons having 3 to 8 carbon atoms include saturated cyclic hydrocarbons such as cyclopropane, cyclobutane, cyclopentane, cyclohexane, cycloheptane, and cyclooctane, and unsaturated cyclic hydrocarbons such as cyclopropene, cyclobutene, cyclopentene, cyclohexene, cycloheptene, cyclooctene, and cyclooctadiene.

[0053] Examples of inorganic gases include gases such as H ２ , CO, CO ２ , N ２ , O ２ , NO, carbon tetrafluoride, sulfur hexafluoride, He, Ar, etc.

[0054] Examples of the gas to be treated include, for example, natural gas containing CO ２ and methane. When separating natural gas containing CO ２ and methane with an inorganic membrane element including a DDR - type zeolite membrane, methane with a low permeability is concentrated on the non - permeation side, and CO ２ with a high permeability is concentrated on the permeation side, respectively. Natural gas contains, as other components, for example, ethane, propane, n - butane, n - hexane, He, etc.

[0055] The conditions for the separation process of the gas to be treated are not particularly limited. The temperature of the separation process is preferably 20°C to 300°C, more preferably 25°C to 250°C, and even more preferably 50°C to 200°C. The supply pressure of the gas to be treated is preferably 1 MPaG or higher, more preferably 2 MPaG or higher, and even more preferably 3 MPaG or higher. The upper limit of the supply pressure of the gas to be treated is set to an extent that does not damage the inorganic membrane element, and is usually 20 MPaG or lower. The differential pressure between the non-permeable side and the permeable side (pressure on the non-permeable side - pressure on the permeable side) is preferably 10 kPaG to 600 kPaG, more preferably 50 kPaG to 300 kPaG. The supply rate of the gas to be treated can be set, for example, in a range such that the linear velocity of the non-permeable gas is 1.0 m / s to 15 m / s, preferably 1.5 m / s to 12 m / s, and more preferably 2.0 m / s to 10 m / s. By setting the supply rate of the gas to be treated so that the linear velocity of the non-permeable gas is 15 m / s or less, damage to the inorganic film element can be prevented.

[0056] [Regeneration Process] During the separation of the gas to be treated, at least a portion of the components of the gas to be treated adheres to the surface or pores of the inorganic membrane element as impurities and remains there, blocking the pores. As a result, the separation performance of the inorganic membrane element, specifically its permeability, decreases. For example, when natural gas is supplied as the gas to be treated to the gas supply side of an inorganic membrane element containing a DDR-type zeolite membrane, hydrocarbons such as n-hexane, n-heptane, and n-octane adhere to the surface or pores of the DDR-type zeolite membrane, reducing the separation performance.

[0057] The regeneration process may be performed by bringing a regeneration fluid into contact with the used inorganic membrane element. Through the regeneration process, impurities adsorbed on the membrane surface or in the pores diffuse into the regeneration fluid, are carried away by the flow of the regeneration fluid, and are removed from the inorganic membrane element.

[0058] Used inorganic film elements may be regenerated by heating.

[0059] The recycled fluid is not particularly limited, but for example, CO ２ Gas; CO ２Examples include supercritical fluids of methane, ethane, propane, ethylene, or propylene; and hydrocarbon gases having 1 to 7 carbon atoms. The temperature, pressure, and supply rate of the regeneration fluid, as well as the regeneration processing time, can be appropriately determined within a range that allows for the regeneration of the inorganic membrane element while minimizing damage to the inorganic membrane element.

[0060] The regenerating fluid may be supplied to the treated gas supply side or the non-permeable side of the inorganic film element, or it may be supplied to the permeable side of the inorganic film element.

[0061] The regeneration process may be performed within the housing of the gas separation membrane module without removing the inorganic membrane element from the gas separation membrane module. Alternatively, the regeneration process may be performed in an external container after removing the inorganic membrane element from the housing of the gas separation membrane module and placing it in the external container. The external container may be a pressure vessel.

[0062] It will be apparent to those skilled in the art that the above embodiments and examples can be modified in various ways without departing from the basic principles of the present invention. It will also be apparent to those skilled in the art that various improvements and modifications of the present invention can be implemented without departing from the spirit and scope of the present invention.

[0063] 10 Gas separation device 11 Array 12 Support part 20 Gas separation membrane module 21 Cylindrical housing 211 Flange part 212 Gas to be processed supply port 213 Permeate gas outlet 214 Impermeable gas outlet 215 Regenerative fluid inlet 22 Inorganic membrane element 221 Cell 222 Porous support 23 Perforated housing 24 Seal 25 First connection jig 26 Second connection jig 27 Fastener V Ｄ Vertical direction L of the gas separation device Ｄ Longitudinal direction of the array: G - Gas to be treated, P - Permeate gas, NP - Non-permeate gas

Claims

1. A gas separation apparatus comprising: at least one array including a plurality of gas separation membrane modules connected in series; and at least one support portion supporting the at least one array, wherein each of the plurality of gas separation membrane modules includes a cylindrical housing having flanges at both ends and at least one inorganic membrane element housed within the cylindrical housing; the plurality of gas separation membrane modules are connected by fixing the flanges of the cylindrical housings together; and the support portion supports the at least one array such that its longitudinal direction extends along the longitudinal direction of the gas separation apparatus.

2. The gas separation apparatus according to claim 1, wherein the cylindrical housing comprises a gas to be treated supply port, a permeable gas outlet, and a non-permeable gas outlet, and the plurality of gas separation membrane modules are connected such that the non-permeable gas outlet and the gas to be treated supply port are in gas communication.

3. The gas separation apparatus according to claim 1 or 2, wherein the at least one inorganic membrane element includes a DDR-type zeolite membrane.

4. The gas separation apparatus according to claim 1 or 2, wherein the at least one inorganic membrane element housed in the cylindrical housing is two inorganic membrane elements connected in series.

5. The gas separation apparatus according to claim 1 or 2, further comprising a regeneration mechanism for regenerating the at least one inorganic membrane element.

6. The gas separation apparatus according to claim 1 or 2, further comprising a centering mechanism that maintains the longitudinal direction of at least one array so as to extend along the longitudinal direction of the gas separation apparatus.

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