Mixed gas separation device, mixed gas separation process and membrane reactor

Abstract

In each of the first cells (111a), both ends are open longitudinally, and each cell has an inner surface on which a separating membrane (12) is formed. In a second cell (111b), both ends are closed longitudinally. A support (11) further comprises a slot (117) extending from an outer surface (112) of the support (11) to the second cell (111b). A mixed gas is supplied to an end face in the longitudinal direction (114) of the separating membrane complex (1). A purge gas is supplied to the slot (117), which is open into the outer surface (112) of the support (11).A / C is greater than or equal to 1 and less than or equal to 50, and B / C is greater than or equal to 0.5 and less than or equal to 20, where A is a sum of cross-sectional areas of each first cell (111a) perpendicular to the longitudinal direction, B is a sum of cross-sectional areas of each second cell (111b) perpendicular to the longitudinal direction, and C is a sum of opening areas of each slot (117) located in one of the end sections in the longitudinal direction on the outer surface (112) of the support (11). This enables an improvement in the separation efficiency of the separation device (2) for a mixed gas.

Description

TECHNICAL FIELD

[0001] The present invention relates to a mixed gas separation apparatus, a mixed gas separation method and a membrane reactor. CROSS-REFERENCE TO RELATED APPLICATIONS

[0002] This application claims priority to Japanese Patent Application No. JP 2022-017639, filed with the Japan Patent Office on February 8, 2022, the entire disclosure of which is incorporated herein by reference. STATE OF THE ART

[0003] Currently, various studies and developments are being conducted regarding processing such as separation or adsorption of specific molecules using a separation membrane such as a zeolite membrane.

[0004] For example, International Publication No. 2016 / 104048 (Document 1) and International Publication No. 2016 / 104049 (Document 2) disclose gas separation modules for separating a specific gas from a mixed gas, having a gas separation membrane structure in which a gas separation membrane is formed on a porous support. In the gas separation module, the interior of a casing having the plate-like gas separation membrane structure is divided into two spaces, and the mixed gas is supplied to one of the two spaces (i.e., the supply-side space). Then, the specific gas (hereinafter referred to as the "permeable gas") in the mixed gas passes through the gas separation membrane structure and flows to the other space (i.e., the permeate-side space) and is separated from the mixed gas.In the case where the concentration of the gas to be permeated in the mixed gas is low, a purge gas is introduced into the space on the permeate side in the gas separation module so that the partial pressure of the gas to be permeated in the space on the permeate side is reduced and the permeation of the gas to be permeated is accelerated.

[0005] As an example of separation membrane structures for separating the specific gas from the mixed gas, a monolith-type separation membrane complex is known. The separation membrane complex comprises a matrix of a plurality of cells arranged therein, each of which penetrates a columnar porous support in a longitudinal direction, and a separation membrane formed on the inner surfaces of the cells. This increases the area of ​​the separation membrane per unit volume of the separation membrane complex and improves the separation efficiency of the separation membrane complex.

[0006] In the case of separating a low-concentration permeable gas from a mixed gas by a mixed gas separation device using the above-described monolith-type separation membrane complex, it is conceivable to supply a purge gas to the space outside the columnar porous support. However, the effect of accelerating permeation by the purge gas is not so pronounced on cells located away from the space where the purge gas flows (e.g., cells located near a central portion of the porous support in a section perpendicular to the longitudinal direction), so there is a limit to improving the separation performance of the mixed gas separation device for a mixed gas. SUMMARY OF THE INVENTION

[0007] The present invention is for a mixed gas separation apparatus, and it is an object of the present invention to improve the performance of separating a mixed gas.

[0008] A mixed gas separation device according to a preferred embodiment of the present invention relates to a separation membrane complex comprising a separation membrane and a porous support, and a housing comprising the separation membrane complex. The support has a columnar shape extending in a longitudinal direction. The support includes a plurality of cells arranged in a longitudinal direction and a lateral direction in a matrix. The plurality of cells includes a plurality of membrane-formed cells each having both ends open in the longitudinal direction and each having an inner surface on which the separation membrane is formed, and a discharge cell each having both ends closed in the longitudinal direction. The support has end portions in the longitudinal direction, in both of which a side flow path is formed, extending from an outer surface of the support to the discharge cell.The housing is connected to a mixed gas supply device that supplies a mixed gas comprising a plurality of types of gases to the separation membrane complex, a permeated gas collector that collects a permeated gas in the mixed gas, the permeated gas having passed through the separation membrane, a non-permeated gas collector that collects a non-permeated gas in the mixed gas, the non-permeated gas not having passed through the separation membrane, and a purge gas supply device that supplies a purge gas. The mixed gas is supplied to an end face in the longitudinal direction of the separation membrane complex. The purge gas is supplied to the side flow path open into the outer surface of the support.A / C is greater than or equal to 1 and less than or equal to 50 and B / C is greater than or equal to 0.5 and less than or equal to 20, where A is a sum of cross-sectional areas of each of the plurality of cells formed by a membrane perpendicular to the longitudinal direction, B is a sum of cross-sectional areas of each discharge cell perpendicular to the longitudinal direction and C is a sum of opening areas of each side flow path located in one of the end portions in the longitudinal direction on the outer surface of the support.

[0009] The mixed gas separation device achieves improved performance in separating the mixed gas.

[0010] Preferably, the support further comprises another side flow path extending from the outer surface of the support to the delivery cell at a position in the longitudinal direction that is different from a position in the longitudinal direction of the side flow path. The purge gas supplied to the side flow path is discharged through the delivery cell and the another side flow path to the environment of the separation membrane complex.

[0011] Preferably, the separation membrane complex further comprises a cover having a higher density than the support and covering the outer surface of the support between the side flow path and the further side flow path.

[0012] Preferably, each of the plurality of cells formed by a membrane is adjacent to the delivery cell or the outer surface of the support.

[0013] Preferably, the purge gas contains at least one of water, air, nitrogen, oxygen and carbon dioxide.

[0014] Preferably, the separation membrane is a zeolite membrane.

[0015] Preferably, a zeolite forming the zeolite membrane is formed from a ring with a maximum of 8 or fewer members.

[0016] Preferably, the mixed gas contains one or more kinds of substances from hydrogen, helium, nitrogen, oxygen, water, carbon monoxide, carbon dioxide, nitrogen oxides, ammonia, sulfur oxides, hydrogen sulfide, sulfur fluoride, mercury, arsine, hydrogen cyanide, carbonyl sulfide, C1 to C8 hydrocarbons, organic acids, alcohol, mercaptans, esters, ethers, ketone and aldehyde.

[0017] The present invention is also provided for a mixed gas separation method. A mixed gas separation method according to a preferred embodiment of the present invention comprises a) preparing a separation membrane complex comprising a separation membrane and a porous support, and b) supplying a mixed gas containing a plurality of types of gases to the separation membrane and allowing a high-permeability gas in the mixed gas to pass through the separation membrane, so that the high-permeability gas is separated from the mixed gas. The support has a columnar shape extending in a longitudinal direction. The support comprises a plurality of cells arranged in a matrix in a longitudinal direction and a lateral direction.The plurality of cells comprises a plurality of membrane-formed cells each having both ends open in the longitudinal direction and an inner surface on which the separation membrane is formed, and a discharge cell having both ends closed in the longitudinal direction. The support has end portions in the longitudinal direction, in both of which a side flow path is formed, extending from an outer surface of the support to the discharge cell. The operation comprises b) supplying a mixed gas to an end surface in the longitudinal direction of the separation membrane complex and supplying a purge gas to the side flow path open into the outer surface of the support.A / C is greater than or equal to 1 and less than or equal to 50 and B / C is greater than or equal to 0.5 and less than or equal to 20, where A is a sum of cross-sectional areas of each of the plurality of cells formed by a membrane perpendicular to the longitudinal direction, B is a sum of cross-sectional areas of each discharge cell perpendicular to the longitudinal direction and C is a sum of opening areas of each side flow path located in one of the end portions in the longitudinal direction on the outer surface of the support.

[0018] The present invention is also provided for a membrane reactor. A membrane reactor according to a preferred embodiment of the present invention comprises a separation membrane complex comprising a separation membrane and a porous support, a catalyst that accelerates a chemical reaction of a starting material, and a casing containing the separation membrane complex and the catalyst. The support has a columnar shape extending in a longitudinal direction. The support includes a plurality of cells arranged in a longitudinal direction and a lateral direction in a matrix. The plurality of cells includes a plurality of cells formed by a membrane, each of which has both ends open in the longitudinal direction and has an inner surface on which the separation membrane is formed, and a discharge cell having both ends closed in the longitudinal direction.The support has end portions in the longitudinal direction, each of which has a side flow path formed therein, extending from an outer surface of the support to the delivery cell. The catalyst is arranged in the plurality of cells of the separation membrane complex formed by a membrane.The housing is connected to a source gas supply device that supplies a source gas containing a starting material to the separation membrane complex, a permeated gas collector that collects a permeated gas into a mixed gas, the permeated gas having passed through the separation membrane, the mixed gas being generated by a chemical reaction of the starting material taking place in the presence of the catalyst, a non-permeated gas collector that collects a non-permeated gas into the mixed gas, the non-permeated gas not having passed through the separation membrane, and a purge gas supply device that supplies a purge gas. The source gas is supplied to an end face in the longitudinal direction of the separation membrane complex. The purge gas is supplied to the side flow path open into the outer surface of the support.A / C is greater than or equal to 1 and less than or equal to 50 and B / C is greater than or equal to 0.5 and less than or equal to 20, where A is a sum of cross-sectional areas of each of the plurality of cells formed by a membrane perpendicular to the longitudinal direction, B is a sum of cross-sectional areas of each discharge cell perpendicular to the longitudinal direction and C is a sum of opening areas of each side flow path located in one of the end portions in the longitudinal direction on the outer surface of the support.

[0019] These and other objects, features, aspects and advantages of the present invention will become more apparent from the following detailed description of the present invention when taken in conjunction with the accompanying drawings. BRIEF DESCRIPTION OF THE DRAWINGS Fig. 1 is a side view of a separating device according to a first embodiment. Fig. Figure 2 is a perspective view of a separation membrane complex. Fig. Figure 3 is a diagram showing an end face of the separation membrane complex. Fig. Figure 4 is a diagram showing a portion of a longitudinal section of the separation membrane complex with enlarged dimensions. Fig. Figure 5 is a diagram showing an end face of the separation membrane complex. Fig. Figure 6 is a flow diagram showing the preparation of the separation membrane complex. Fig. 7 is a sectional view of the separating device. Fig. Figure 8 is a flow diagram showing the separation of a mixed gas. Fig. 9 is a side view of the separator. Fig. 10 is a side view of a separating device according to a second embodiment. Fig. 11 is a sectional view of the separating device. Fig. 12 is a side view of a mixed gas separation system. Fig. 13 is a sectional view of a membrane reactor. Fig. Figure 14 is a diagram showing the method of operating the membrane reactor. Fig. 15 is a side view of the separator. DESCRIPTION OF EMBODIMENTS

[0020] The Fig. 1 is a side view showing a mixed gas separation device 2 according to a first embodiment of the present invention. The mixed gas separation device 2 (hereinafter also referred to simply as the "separation device 2") is a device for separating a specific type of gas from a mixed gas containing a plurality of types of gases.

[0021] The separation device 2 comprises a separation membrane complex 1 and a housing 22 which comprises the separation membrane complex 1. The Fig. 1 is a sectional view of the casing 22 of the separation device 2, showing an internal structure of the casing 22. The separation device 2 allows a gas in the mixed gas having a high permeability to pass through the separation membrane complex 1, so that the gas is separated from the mixed gas.

[0022] The Fig. Figure 2 is a perspective view of the separation membrane complex 1. The Fig. 2 also shows part of an internal structure of the separation membrane complex 1. The Fig. Figure 3 is a diagram showing an end face 114 in the longitudinal direction of the separation membrane complex 1 (ie, approximately the right-left direction in the Fig. 2). The Fig. Figure 4 is a diagram showing a part of a longitudinal section of the separation membrane complex 1 in enlarged dimensions and showing the environment of a cell 111, which will be described later.

[0023] The separation membrane complex 1 comprises a porous carrier 11 and a separation membrane 12 (see the Fig. 4) formed on the carrier 11. In the Fig. 4, the separation membrane 12 is hatched. The carrier 11 is a porous element that is permeable to a gas and a liquid. In the Fig. In the example shown in Figure 2, the support 11 is a monolithic support comprising an integrally formed columnar body with a plurality of through-holes 111 (hereinafter also referred to as "cells 111") each extending in the longitudinal direction of the body. In the support 11, the cells 111 are formed (ie, divided) by a porous partition wall. In the example shown in Figure 2, Fig. 2, the support 11 has an approximately columnar outer shape. Each cell 111 may, for example, have an approximately circular cross-sectional shape perpendicular to the longitudinal direction. It should be noted that “approximately circular” refers to a concept that includes not only a perfect circle, but also an ellipse or a distorted circle. It is preferred that each cell 111 has a perfectly circular cross-sectional shape, however, this cross-sectional shape does not necessarily have to be a perfect circle. In the illustration in the Fig. 2, the diameter of the cells 111 is larger than the actual diameter and the number of cells 111 is smaller than the actual number (the same applies to the Fig. 3).

[0024] The cells 111 comprise first cells 111a and second cells 111b. In the Fig. 2 and Fig. In the example shown in Figure 3, the first cells 111a and the second cells 111b have approximately the same shape. The openings of the second cells 111b are closed by a closure element 115 in both end surfaces in the longitudinal direction 114 of the carrier 11. In other words, both ends of the second cells 111b are closed in the longitudinal direction. Fig. 2 and Fig. 3, the closure element 115 is hatched. Furthermore, the openings of the first cells 111a are not closed, but are open in both end surfaces in the longitudinal direction 114 of the carrier 11.

[0025] The above-mentioned separation membrane 12 (see the Fig. 4) is formed on the inner surface of each first cell 111a, both ends of which are open in the longitudinal direction. Preferably, the separation membrane 12 may be formed to cover the entire inner surface of each first cell 111a. That is, the first cells 111a are membrane-formed cells, and the separation membrane 12 is formed on the inner surface thereof. In the separation membrane complex 1, the separation membrane 12 is not formed on the inner surface of the second cells 111b. As described later, the second cells 111b are discharge cells used for discharging a permeated gas that has passed through the separation membrane 12.

[0026] In the example shown in the Fig. 2 and Fig. 3, the cells 111 are arranged in the longitudinal direction (ie, the top-bottom direction in the Fig. 3) and the lateral direction in a matrix in the end faces 114 of the carrier 11. In the following description, a group of cells 111 arranged in a line in the lateral direction (ie, the right-left direction in the Fig. 3), also referred to as a “cell line.” The cells 111 comprise a plurality of cell lines arranged in the longitudinal direction. In the example shown in the Fig. 3, each cell line is composed of a plurality of first cells 111a or a plurality of second cells 111b.

[0027] In the example shown in the Fig. 3, the cell lines are arranged such that one cell line of second cells 111b (hereinafter also referred to as "second cell line 116b") and two cell lines of first cells 111a (hereinafter also referred to as "first cell lines 116a") are alternately arranged adjacent to each other in the longitudinal direction. Fig. 3, the first cell lines 116a and the second cell lines 116b are each surrounded by a double-dash line (the same applies to the Fig. 5, which will be described later). The second cell lines 116b are closed cell lines in which both ends are closed in the longitudinal direction.

[0028] A plurality of second cells 111b in every second cell line 116b protrudes above a slot 117 (see the Fig. 2) extending in a lateral direction, communicate with each other. The slit 117 extends to an outer surface 112 of the substrate 11 on both lateral sides of the second cell line 116b, so that the second cells 111b in the second cell line 116b communicate with the space outside the substrate 11 via the slit 117. In other words, each slit 117 serves as a side flow path extending from the outer surface of the substrate 11 to a second cell 111b and extending through the second cell line 116b (i.e., a plurality of second cells 111b aligned in the lateral direction) in the lateral direction to the outer surface of the substrate 11. In other words, each slot 117 connects a plurality of second cells 111b in each second cell line 116b and portions of the outer surface of the carrier 11 located on both lateral sides of the second cell line 116b.

[0029] For example, each slot 117 may have an approximately rectangular cross-sectional shape perpendicular to the lateral direction. The cross-sectional shape of the slot 117 may be changed to any of various shapes, such as a circular shape. It should be noted that this cross-sectional area of ​​the slot 117 is much larger than the cross-sectional areas of the pores of the carrier 11. For example, the cross-sectional area of ​​each slot 117 perpendicular to the lateral direction may be in the range of 5 to 100 times the cross-sectional area of ​​every other cell 111b perpendicular to the longitudinal direction.

[0030] In the separation membrane complex 1, three slits 117 are formed in the vicinity of an end portion in the longitudinal direction of the support 11. Since each slit 117 is open into the outer surface of the support 11 on both lateral sides, six openings (hereinafter also referred to as "slit openings") are present in the vicinity of the above-mentioned end portion of the outer surface of the support 11. In the Fig. 2, these six slit openings have approximately the same shape and are located at approximately the same position in the longitudinal direction. In the separation membrane complex 1, three slits 117 are also formed in the vicinity of the other end portion in the longitudinal direction of the substrate 11 (that is, at a position in the longitudinal direction different from the position in the longitudinal direction of the above-mentioned three slits 117), so that six slit openings are also present in the vicinity of the other end portion of the outer surface of the substrate 11. These six slit openings also have approximately the same shape and are located at approximately the same position in the longitudinal direction. In the vicinity of each end portion in the longitudinal direction of the substrate 11, some or all of the slit openings (of the above-mentioned six slit openings) may differ in shape or position.

[0031] The first cell lines 116a are open cell lines in which both ends are open in the longitudinal direction, and are also cell lines formed by a membrane, on the inside of which the separation membrane 12 is formed (cf. the Fig. 4). Two lines of first cells 111a that are adjacent to a longitudinal side of a second cell line 116b form an open cell line group. In other words, the open cell line group refers to two first cell lines 116a that are enclosed between two second cell lines 116b that are closest to each other in the longitudinal direction.

[0032] The number of first cell lines 116a forming an open cell line group is not limited to two and can be varied in various ways. Preferably, the number of first cell lines 116a forming an open cell line group can be greater than or equal to one and less than or equal to six, and more preferably one or two. Fig. 5 shows an example in which five first cell lines 116a form an open cell line group enclosed between two second cell lines 116b.

[0033] The number of second cell lines 116b is also not limited to three and may be one or two or more. In the separation membrane complex 1, the second cells 111b do not necessarily have to be aligned in the lateral direction and may be arranged at random intervals. As a further alternative, the number of second cells 111b arranged in the separation membrane complex 1 may be one.

[0034] The carrier 11 may have a length in the longitudinal direction of, for example, 100 mm to 2000 mm. The carrier 11 may have an outer diameter of, for example, 5 mm to 300 mm. The cell-to-cell spacing between each pair of adjacent cells 111 (i.e., the thickness of the carrier 11 between portions of the adjacent cells 111 that are closest to each other) may be in the range of, for example, 0.3 mm to 10 mm. The surface roughness (Ra) of the inner surfaces of the first cells 111a of the carrier 11 may be in the range of, for example, 0.1 µm to 5.0 µm, and preferably in the range of 0.2 µm to 2.0 µm. A cross-sectional area of ​​each cell 111 perpendicular to the longitudinal direction may be in the range of, for example, greater than or equal to 2 mm 2 and less than or equal to 300 mm 2If this portion of each cell 111 has an approximately circular shape, as described above, the diameter of this portion may preferably be in the range of 1.6 mm to 20 mm. It should be noted that the shapes and sizes of the substrate 11 and each cell 111 may be variously changed. For example, the cells 111 may have an approximately polygonal cross-sectional shape perpendicular to the longitudinal direction. The first cells 111a and the second cells 111b may differ in shape and size. Furthermore, some or all of the first cells 111a may differ in shape and size, and some or all of the second cells 111b may differ in shape and size.

[0035] The material for the support 11 can be any of various substances (e.g., ceramic or metal), as long as this substance has chemical stability in the process of forming the separation membrane 12 on the surface of the support 11. In the present embodiment, the support 11 is formed from a ceramic sintered body. Examples of the ceramic sintered body selected as the material for the support 11 include alumina, silicon oxide, mullite, zirconia, titanium oxide, yttrium oxide, silicon nitride, and silicon carbide. In the present embodiment, the support 11 contains at least one of alumina, silicon oxide, and mullite.

[0036] The support 11 may contain an inorganic binder for binding aggregate particles of the aforementioned ceramic sintered body. At least one of titanium oxide, mullite, easily sintered alumina, silica, glass frit, clay minerals, and easily sintered cordierite may be used as the inorganic binder.

[0037] The carrier 11 may, for example, have a multilayer structure in which a plurality of layers having different average pore diameters in the thickness direction are laminated one on top of the other in the vicinity of the inner surface of each first cell 111a as an open cell (ie, in the vicinity of the separation membrane 12). In the Fig. 4, the carrier 11 comprises a porous base material 31, a porous intermediate layer 32 formed on the base material 31, and a porous surface layer 33 formed on the intermediate layer 32. That is, the surface layer 33 is indirectly formed on the base material 31 via the intermediate layer 32. The intermediate layer 32 is formed between the base material 31 and the surface layer 33. The surface layer 33 forms the inner surface of each first cell 111a of the carrier 11, and the separation membrane 12 is formed on the surface layer 33. The surface layer 33 may have a thickness of, for example, 1 µm to 100 µm. The intermediate layer 32 may have a thickness of, for example, 100 µm to 500 µm. It should be noted that the intermediate layer 32 and the surface layer 33 may or may not be formed on the inner surface of every other cell 111b.Furthermore, the intermediate layer 32 and the surface layer 33 may or may not be formed on the outer surface 112 and the end surfaces 114 of the carrier 11.

[0038] The average pore diameter of the surface layer 33 is smaller than the average pore diameters of the intermediate layer 32 and the base material 31. The average pore diameter of the intermediate layer 32 is smaller than the average pore diameter of the base material 31. The average pore diameter of the base material 31 can be, for example, greater than or equal to 1 µm and less than or equal to 70 µm. The average pore diameter of the intermediate layer 32 can be, for example, greater than or equal to 0.1 µm and less than or equal to 10 µm. The average pore diameter of the surface layer 33 can be, for example, greater than or equal to 0.005 µm and less than or equal to 2 µm. The average pore diameters of the base material 31, the intermediate layer 32, and the surface layer 33 can be measured, for example, using a mercury porosimeter, a permporometer, or a nano-permporometer.

[0039] The surface layer 33, the intermediate layer 32, and the base material 31 have approximately the same porosity. The porosities of the surface layer 33, the intermediate layer 32, and the base material 31 can, for example, be greater than or equal to 15% and less than or equal to 70%. The porosities of the surface layer 33, the intermediate layer 32, and the base material 31 can be measured, for example, using the Archimedes method, mercury porosimetry, or image analysis.

[0040] The base material 31, the intermediate layer 32, and the surface layer 33 may be formed of the same material or may be formed of different materials. For example, the base material 31 and the surface layer 33 may contain Al2O3 as a main material. The intermediate layer 32 may contain aggregate particles containing Al2O3 as a main material and an inorganic binder containing TiO2 as a main material. In the present embodiment, the aggregate particles of the base material 31, the intermediate layer 32, and the surface layer 33 are formed substantially only of Al2O3. The base material 31 may contain an inorganic binder such as glass.

[0041] The average particle diameter of the aggregate particles in the surface layer 33 is smaller than the average particle diameter of the aggregate particles in the intermediate layer 32. The average particle diameter of the aggregate particles in the intermediate layer 32 is smaller than the average particle diameter of the aggregate particles in the base material 31. The average particle diameters of the aggregate particles in the base material 31, the intermediate layer 32, and the surface layer 33 can be measured, for example, by a laser diffraction method.

[0042] The closure element 115 can be formed from a material that corresponds to or is similar to the material(s) for the base material 31, the intermediate layer 32, and the surface layer 33. The porosity of the closure element 115 can range from, for example, 15% to 70%.

[0043] As described above, the separation membrane 12 is formed on the inner surface of each first cell 111a as an open cell (i.e., on the surface layer 33) and covers approximately the entire inner surface. The separation membrane 12 is a porous membrane with microscopic pores. The separation membrane 12 separates a specific substance from a mixture of substances comprising a plurality of types of substances.

[0044] The separation membrane 12 may preferably be an inorganic membrane formed of an inorganic material, more preferably any of a zeolite membrane, a silica membrane, a carbon membrane, and a metal-organic framework (MOF) membrane, and particularly preferably a zeolite membrane. The zeolite membrane refers to at least one membrane obtained by forming a zeolite in a membrane shape on the surface of the support 11, and does not include a membrane obtained by merely dispersing zeolite particles in an organic membrane. In the present embodiment, the separation membrane 12 is a zeolite membrane. The separation membrane 12 may be a zeolite membrane containing two or more types of zeolites having different structures or compositions.

[0045] The separation membrane 12 can have a thickness of, for example, greater than or equal to 0.05 µm and less than or equal to 50 µm, preferably greater than or equal to 0.1 µm and less than or equal to 20 µm, and more preferably greater than or equal to 0.5 µm and less than or equal to 10 µm. Increasing the thickness of the separation membrane 12 improves the separation performance. Decreasing the thickness of the separation membrane 12 increases the permeability. The surface roughness (Ra) of the separation membrane 12 can be, for example, less than or equal to 5 µm, preferably less than or equal to 2 µm, more preferably less than or equal to 1 µm, and even more preferably less than or equal to 0.5 µm. The pore diameter of the separation membrane 12 can be in the range of, for example, 0.2 nm to 1 nm. The pore diameter of the separation membrane 12 is smaller than the average pore diameter in the surface layer 33 of the carrier 11.

[0046] When the zeolite forming the separation membrane 12 is composed of a maximum n-membered ring, the minor axis of the n-membered ring pore is taken as the pore diameter of the separation membrane 12. When the zeolite comprises a plurality of types of n-membered ring pores, where n is the same number, the minor axis of an n-membered ring pore with a largest minor axis is taken as the pore diameter of the separation membrane 12. It should be noted that the n-membered ring refers to a ring in which n oxygen atoms form the basic framework of each pore, and each oxygen atom is bonded to T atoms described later, forming a cyclic structure. The n-membered ring also refers to a ring that forms a through-hole (channel) and does not include a ring that does not form a through-hole. The n-membered ring pore refers to a pore formed from an n-membered ring.In view of improving the selectivity, it is preferred that the zeolite constituting the zeolite membrane 12 is composed of a ring having a maximum of 8 or fewer members (e.g., a 6- or 8-membered ring).

[0047] The pore diameter of the separation membrane 12 is uniquely determined by the framework structure of the zeolite and can be obtained from values ​​disclosed in “Database of Zeolite Structures” [Online] by the International Zeolite Association, Internet<URL:http: / / www.iza-structure.org / databases / > .

[0048] There are no specific restrictions on the type of zeolite constituting the separation membrane 12, and the zeolite can be, for example, an AEI, AEN, AFN, AFV, AFX, BEA, CHA, DDR, ERI, ETL, FAU (X-type, Y-type), GIS, IHW, LEV, LTA, LTJ, MEL, MFI, MOR, PAU, RHO, SOD, or SAT type zeolite. When the zeolite is an 8-membered ring zeolite, the zeolite can be, for example, an AEI, AFN, AFV, AFX, CHA, DDR, ERI, ETL, GIS, IHW, LEV, LTA, LTJ, RHO, or SAT type zeolite. In the present embodiment, the zeolite constituting the separation membrane 12 is a DDR type zeolite.

[0049] The zeolite forming the separation membrane 12 may, for example, contain at least one of silicon (Si), aluminum (Al), and phosphorus (P) as T atoms (i.e., atoms located at the center of an oxygen tetrahedron (TO4) forming the zeolite). The zeolite forming the separation membrane 12 may, for example, be a zeolite in which T atoms are composed only of Si or of Si and Al, an AlPO-type zeolite in which T atoms are composed of Al and P, a SAPO-type zeolite in which T atoms are composed of Si, Al, and P, a MAPSO-type zeolite in which T atoms are composed of magnesium (Mg), Si, Al, and P, or a ZnAPSO-type zeolite in which T atoms are composed of zinc (Zn), Si, Al, and P. Some of the T atoms may be replaced by other elements. The zeolite forming the separation membrane 12 may contain an alkali metal. The alkali metal may be, for example, sodium (Na) or potassium (K).

[0050] When the zeolite constituting the separation membrane 12 contains Si atoms and Al atoms, the Si / Al ratio in the zeolite of the separation membrane 12 may be, for example, higher than or equal to one and lower than or equal to one hundred thousand. The Si / Al ratio refers to the molar ratio of the Si element to the Al element contained in the zeolite of the separation membrane 12. The Si / Al ratio may preferably be higher than or equal to 5, more preferably higher than or equal to 20, and even more preferably higher than or equal to 100. It is preferable that the Si / Al ratio be as high as possible because the separation membrane 12 can then achieve higher resistance to heat and acids. The Si / Al ratio can be adjusted, for example, by the mixing ratio of a Si source and an Al source in a raw material solution, which will be described later.

[0051] For example, when a difference in the partial pressure of CO2 between the feed side and the permeate side of the zeolite membrane 12 is 1.5 MPa, the CO2 permeability (permeability) of the zeolite membrane 12 at temperatures from 20 °C to 400 °C can be higher than or equal to 100 nmol / (m 2 . s · Pa) and the ratio between the CO2 permeability and the CH4 leakage in the zeolite membrane 12 (permeability ratio) at temperatures from 20 °C to 400 °C may, for example, be higher than or equal to 25. When the above-mentioned difference in the partial pressure of CO2 is 0.2 MPa, the above-mentioned permeability may, for example, be higher than or equal to 200 nmol / (m 2 · s · Pa) and the above-mentioned permeability ratio may, for example, be higher than or equal to 60.

[0052] Next, an example of the method for producing the separation membrane complex 1 will be described with reference to Fig. 6. In the preparation of the separation membrane complex 1, seed crystals used to form the zeolite membrane 12 are first synthesized and prepared (step S11). In the synthesis of the seed crystals, a starting material such as a Si source and a structure-forming agent (hereinafter also referred to as an "SDA") or the like are dissolved or dispersed in a solvent to prepare a starting material solution of the seed crystals. Then, the starting material solution is subjected to hydrothermal synthesis, and the resulting crystals are washed and dried to obtain zeolite powder. The zeolite powder can be used as the seed crystals as it is, or can be subjected to processing such as pulverization to obtain the seed crystals.

[0053] Then, a dispersion obtained by dispersing the seed crystals in a solvent (e.g., water) is brought into contact with the inner surfaces of the first cells 111a of the carrier 11, so that the seed crystals in the dispersion are deposited on the inner surfaces of the first cells 111a (step S12). It should be noted that the seed crystals can be deposited on the inner surfaces of the first cells 111a by any other technique. For example, in step S12, both end portions in the longitudinal direction of every other cell 111b can be sealed in advance.

[0054] Then, the support 11 with the seed crystals deposited thereon is immersed in a source material solution. The source material solution can be prepared by dissolving, for example, a Si source and an SDA in a solvent. The solvent in the source material solution can be, for example, water or an alcohol such as ethanol. The SDA contained in the source material solution can be, for example, an organic material. For example, 1-adamantanamine can be used as the SDA.

[0055] Then, the zeolite is grown by hydrothermal synthesis using the aforementioned seed crystals as the core, so that the zeolite membrane 12 is formed on the inner surface of each first cell 111a of the support 11 (step S13). Preferably, the temperature during the hydrothermal synthesis may be in the range of 120°C to 200°C, for example, 160°C. Preferably, the hydrothermal synthesis time may be in the range of 5 hours to 100 hours, for example, 30 hours.

[0056] When the hydrothermal synthesis is completed, the support 11 and the zeolite membrane 12 are washed with deionized water. After washing, the support 11 and the zeolite membrane 12 can be dried, for example, at 80°C. After drying the support 11 and the zeolite membrane 12, the zeolite membrane 12 is subjected to a heat treatment (i.e., firing) so that the SDA in the zeolite membrane 12 is almost completely removed by firing, and the zeolite membrane 12 is perforated with micropores. Thus, the aforementioned separation membrane complex 1 is obtained (step S14).

[0057] Next, the separation of a mixed gas using the separation membrane complex 1 will be described with reference to the Fig. 1, Fig. 7 and Fig. 8. The Fig. 7 is a sectional view of the separating device 2. To facilitate understanding of the drawing, Fig. 7 a cross-section of the separation membrane complex 1 is shown simplified and schematically. Fig. 8 is a flowchart showing the separation of a mixed gas using the separator 2.

[0058] The separation device 2 supplies a mixed gas containing a plurality of types of gases to the separation membrane complex 1 and allows a high-permeability gas in the mixed gas to pass through the separation membrane complex 1, so that the high-permeability gas is separated from the mixed gas. Separation by the separation device 2 can be performed to extract a high-permeability gas (hereinafter also referred to as a "high-permeability gas") from the mixed gas or to condense a low-permeability gas (hereinafter also referred to as a "low-permeability gas").

[0059] The mixed gas may, for example, contain one or more types of substances from hydrogen (H2), helium (He), nitrogen (N2), oxygen (O2), water (H2O), carbon monoxide (CO), carbon dioxide (CO2), nitrogen oxides, ammonia (NH3), sulfur oxides, hydrogen sulfide (H2S), sulfur fluoride, mercury (Hg), hydrogen arsine (AsH3), hydrogen cyanide (HCN), carbonyl sulfide (COS), C1 to C8 hydrocarbons, organic acids, alcohol, mercaptans, esters, ethers, ketones, and aldehydes. The above-mentioned high-permeability gas may, for example, be one or more types of substances from CO2, NH3, and H2O. It should be noted that the mixed gas and the high-permeability gas may be substances other than those described above.

[0060] Nitrogen oxides are compounds of nitrogen and oxygen. For example, the nitrogen oxides mentioned above can be substances known as NOx such as nitric oxide (NO), nitrogen dioxide (NO2), nitrous oxide (also called nitrogen monoxide) (N2O), nitrous trioxide (N2O3), nitrous tetroxide (N2O4) or nitrous pentoxide (N2O5).

[0061] Sulfur oxides are compounds of sulfur and oxygen. For example, the sulfur oxides mentioned above can be substances known as SO x such as sulfur dioxide (SO2) or sulfur trioxide (SO3).

[0062] Sulfur fluoride is a compound of fluorine and sulfur. For example, the above-mentioned sulfur fluoride can be disulfur difluoride (FSSF, S=SF2), sulfur difluoride (SF2), sulfur tetrafluoride (SF4), sulfur hexafluoride (SF6) or disulfur decafluoride (S2F 10 ) be.

[0063] C1 to C8 hydrocarbons are hydrocarbons containing one or more and eight or fewer carbon atoms. C3 to C8 hydrocarbons can each be any of a straight-chain compound, a side-chain compound, and a cyclic compound. C2 to C8 hydrocarbons can each be either a saturated hydrocarbon (i.e., having no double bonds or triple bonds in the molecules) or an unsaturated hydrocarbon (i.e., having double bonds and / or triple bonds in the molecules). C1 to C4 hydrocarbons can be, for example, methane (CH4), ethane (C2H6), ethylene (C2H4), propane (C3H8), propylene (C3H6), n-butane (CH3(CH2)2CH3), isobutene (CH(CH3)3), 1-butene (CH2=CHCH2CH3), 2-butene (CH3CH=CHCH3) or isobutene (CH2=C(CH3)2).

[0064] The above-mentioned organic acids can be, for example, carboxylic acids or sulfonic acids. The carboxylic acids can be, for example, formic acid (CH2O2), acetic acid (C2H4O2), oxalic acid (C2H2O4), acrylic acid (C3H4O2), or benzoic acid (C6H5COOH). The sulfonic acids can be, for example, ethanesulfonic acid (C2H6O3S). The organic acids can be either chain compounds or cyclic compounds.

[0065] The above-mentioned alcohol can be, for example, methanol (CH3OH), ethanol (C2H5OH), isopropanol (2-propanol) (CH3CH(OH)CH3), ethylene glycol (CH2(OH)CH2(OH)) or butanol (C4H9OH).

[0066] Mercaptans are organic compounds with terminal sulfur hydrides (SH) and are also known as thiols or thioalcohols. The mercaptans mentioned above can be, for example, methyl mercaptan (CH3SH), ethyl mercaptan (C2H5SH), or 1-propanethiol (C3H7SH).

[0067] The above-mentioned ester may, for example, be a formic acid ester or an acetic acid ester.

[0068] The above-mentioned ether can be, for example, dimethyl ether ((CH3)2O), methyl ethyl ether (C2H5OCH3), diethyl ether ((C2H5)2O) or tetrahydrofuran ((CH2)4O).

[0069] The above-mentioned ketone can be, for example, acetone ((CH3)2CO), methyl ethyl ketone (C2H5COCH3) or diethyl ketone ((C2H5)2CO).

[0070] The above-mentioned aldehyde can be, for example, acetaldehyde (CH3CHO), propionaldehyde (C2H5CHO) or butanal (butyraldehyde) (C3H7CHO).

[0071] As it is in Fig. 1 and Fig. 7, the separation device 2 comprises the separation membrane complex 1, a closure device 21, the housing 22 and three sealing elements 23. The separation membrane complex 1, the closure device 21 and the sealing elements 23 are arranged in the housing 22. In the Fig. In Figure 7, the separation membrane 12 of the separation membrane complex 1 is hatched. The interior of the housing 22 is an enclosed space that is isolated from the space around the housing 22. The housing 22 is connected to a mixed gas supply device 26, a first collection device 27, a second collection device 28, and a purge gas supply device 29.

[0072] The locking device 21 is a member provided at both ends in the longitudinal direction of the carrier 11 (ie, the left-right direction in the Fig. 7) is attached and covers and seals both end surfaces in the longitudinal direction 114 of the substrate 11 and a part of the outer surface 112 in the vicinity of both end surfaces 114. The sealing device 21 prevents the inflow and outflow of gas from both end surfaces 114 of the substrate 11. For example, the sealing device 21 may be a sealing layer made of glass or a resin. In the present embodiment, the sealing device 21 is a glass seal with a thickness of 10 μm to 50 μm. The material and shape of the sealing device 21 can be changed as appropriate. It should be noted that the sealing device 21 has a plurality of openings overlapping the plurality of first cells 111a of the substrate 11 such that both ends in the longitudinal direction of each first cell 111a are not covered with the sealing device 21.This allows fluid to flow in and out of each first cell 111a from both ends in the longitudinal direction.

[0073] The housing 22 is an approximately cylindrical, tubular member. For example, the housing 22 may be made of stainless steel or carbon steel. The longitudinal direction of the housing 22 is approximately parallel to the longitudinal direction of the separation membrane complex 1. One end in the longitudinal direction of the housing 22 (ie, the end on the left side in the Fig. 7) is provided with a first supply port 221, and the other end in the longitudinal direction thereof is provided with a first discharge port 222. The first supply port 221 is connected to the mixed gas supply device 26. The first discharge port 222 is connected to the first collecting device 27.

[0074] The housing 22 has a second discharge opening 223 and a second supply opening 224 on its side. In the example shown in the Fig. As shown in Fig. 7, the second discharge port 223 is arranged in the vicinity of the longitudinal central portion of the housing 22, and the second supply port 224 is arranged between the second discharge port 223 and the first supply port 221 in the longitudinal direction of the housing 22. The second supply port 224 is located at approximately the same position in the longitudinal direction as the slits 117 located in the vicinity of an end portion in the longitudinal direction of the separation membrane complex 1. The second discharge port 223 and the second supply port 224 may be arranged at the same circumferential position around the central axis of the separation membrane complex 1 (i.e., an imaginary straight line extending in the longitudinal direction through the centers of the end surfaces 114 of the separation membrane complex 1) or may be arranged at different circumferential positions. The second discharge port 223 is connected to the second collector 28.The second supply port 224 is connected to the purge gas supply device 29. It should be noted that the shape and material of the housing 22 can be changed in various ways.

[0075] The three sealing elements 23 are arranged longitudinally in the longitudinal direction between the outer surface 112 of the separation membrane complex 1 and the inner surface of the housing 22. Each sealing element 23 is a roughly circular, annular element made of a material impermeable to gas and liquid. The sealing elements 23 can be, for example, O-rings or sealing materials made of a flexible resin. The sealing elements 23 are in close contact with the outer surface 112 of the separation membrane complex 1 and the inner surface of the housing 22 along the entire circumference in the circumferential direction around the aforementioned central axis of the separation membrane complex 1 (hereinafter also simply referred to as the "circumferential direction").It should be noted that the material of the sealing elements 23 may be carbon, metal, or any other inorganic material other than a resin.

[0076] Of the three sealing elements 23, the two sealing elements 23 located at both ends in the longitudinal direction are arranged along the entire circumference of the separation membrane complex 1 in the vicinity of both end portions in the longitudinal direction of the separation membrane complex 1. In each end portion in the longitudinal direction of the separation membrane complex 1, the sealing element 23 is located between the slits 117 and the end surface 114 of the separation membrane complex 1 in the longitudinal direction. Of the three sealing elements 23, the sealing element 23 located between the above-mentioned two sealing elements 23 is located between the second supply port 224 and the second discharge port 223 in the longitudinal direction. This sealing element 23 is also located between the second discharge port 223 and the slits 117, which are located at approximately the same position as the second supply port 224 in the longitudinal direction.

[0077] In the example shown in the Fig. 7, of the three sealing elements 23, the two sealing elements 23 at both ends in the longitudinal direction are each in close contact with the outer surface of the closure device 21 between the slits 117 and the longitudinal end surface 114 of the carrier 11, and are indirectly in close contact with the outer surface 112 of the separation membrane complex 1 via the closure device 21. Of the three sealing elements 23, the remaining one sealing element 23 is directly in close contact with the outer surface 112 of the separation membrane complex 1 at a position between the slits 117 and the second discharge opening 223 in the longitudinal direction. The space between each sealing element 23 and the outer surface 112 of the separation membrane complex 1 and the space between each sealing element 23 and the inner surface of the housing 22 are sealed to substantially prevent gas permeation.

[0078] The mixed gas supply device 26 supplies a mixed gas into the interior of the housing 22 via the first supply opening 221. For example, the mixed gas supply device 26 can comprise a pressure mechanism, such as a blower or a pump, which supplies the mixed gas under pressure to the housing 22. The pressure mechanism can comprise, for example, a temperature control device and a pressure regulating device, which adjust the temperature and pressure of the mixed gas supplied to the housing 22. The first collection device 27 and the second collection device 28 can comprise, for example, a reservoir which stores the gas originating from the housing 22, or a blower or a pump which transfers the discharged gas. The purge gas supply device 29 supplies a purge gas into the interior of the housing 22 via the second supply opening 224. For example, the purge gas supply device 29 can comprise a pressure mechanism, such asa blower or a pump, which directs the purge gas under pressure to the housing 22.

[0079] When separating the mixed gas, the separation membrane complex 1 is first prepared (step S21 in the Fig. 8). Specifically, the separation membrane complex 1 is mounted within the housing 22. Then, the mixed gas supply device 26 introduces a mixed gas containing a plurality of types of gases with different permeabilities through the separation membrane 12 into the housing 22 (specifically, the space on the left side of the left end surface 114 of the separation membrane complex 1), as indicated by the arrow 251 in the Fig. 7. For example, the mixed gas may be predominantly composed of CO2 and CH4. The mixed gas may further contain a gas other than CO2 and CH4. The pressure of the mixed gas supplied from the mixed gas supply device 26 into the housing 22 (ie, the initial pressure) may be in the range of, for example, 0.1 MPa to 20.0 MPa. The temperature of the mixed gas supplied from the mixed gas supply device 26 may be in the range of, for example, 10 °C to 250 °C.

[0080] In the separation device 2, the purge gas supply device 29 supplies a purge gas used for separating the mixed gas into the casing 22, as indicated by the arrow 255, in parallel with the supply of the mixed gas to the separation membrane complex 1 by the mixed gas supply device 26. Specifically, the space into which the purge gas is supplied is an approximately cylindrical space located outward from the outer surface 112 of the separation membrane complex 1 in the radial direction (ie, the radial direction around the above-mentioned central axis), and is also a space between the first and second sealing members 23 from the left of the three sealing members 23 in the Fig. 7. The purge gas can be any of various gases. The purge gas can be a gas composed of a single component or a mixed gas containing multiple types of gases. For example, the purge gas can contain at least one of H2O, air, N2, O2, and CO2. The purge gas can be a substance other than the above-mentioned substances.

[0081] The purge gas supplied from the purge gas supply device 29 into the housing 22 flows through each slot 117 located between the first and second sealing elements 23 from the left side in the Fig. 7, and flows into the second cells 111b, which are penetrated by the slots 117, as indicated by the arrows 256a. In each second cell 111b, the purge gas flows in the Fig. 7 to the right, as indicated by the arrows 256b. This purge gas flows through each slot 117 located between the first and second sealing elements 23 from the right side in the Fig. 7, and flows to a separation space 220 around the separation membrane complex 1, as indicated by the arrows 256c. The separation space 220 is an approximately cylindrical space located radially outward from the outer surface 112 of the separation membrane complex 1 (i.e., around the separation membrane complex 1), and is also a space between the first and second sealing members 23 from the right side of the three sealing members 23. A portion of the purge gas flowing through the second cells 111b also flows from the second cells 111b into the surrounding pores of the support 11 and flows through the support 11 to the separation space 220 from the outer surface 112 of the support 11 and the other second cells 111b.

[0082] Further, the mixed gas supplied from the mixed gas supply device 26 into the housing 22 flows into each first cell 111a of the separation membrane complex 1. As indicated by the arrows 252a, a gas having a high permeability in the mixed gas, that is, a high permeability gas, passes through the separation membrane 12 and the support 11 from the first cells 111a and is transferred from the outer surface 112 of the separation membrane complex 1 to the separation space 220. The high permeability gas which has passed through the separation membrane 12 and the support 11 from the first cells 111a and flowed into the second cells 111b flows through the second cells 111b together with the purge gas to the right as indicated by the arrows 256b, and flows through each slit 117 formed between the first and second sealing members 23 from the right side in the Fig. 7, to the separation space 220, as indicated by the arrows 256c. It should be noted that the high-permeability gas flowing from the first cells 111a into the second cells 111b can pass through the support 11 and be transferred to the separation space 220 without passing through the slits 117.

[0083] In the separation membrane complex 1, the purge gas flows to the separation space 220 through the second cells 111b and through the pores of the support 11, as described above. In other words, the purge gas flows around and in the vicinity of the first cells 111a to the separation space 220 and flows around the outer surface 112 of the support 11. Accordingly, the high-permeability gas that has passed through the separation membrane 12 from the first cells 111a is entrained by the purge gas and rapidly transferred to the separation space 220. This reduces the partial pressure of the high permeability gas on the permeate side of the separation membrane 12 (ie, on the side opposite the interiors of the first cells 111a) and accelerates the flow of the high permeability gas from the feed side of the separation membrane 12 (ie, the interiors of the first cells 111a) to the permeate side.

[0084] As a result of the high-permeability gas (e.g., CO2) passing through the separation membrane 12 and being transferred to the separation space 220 as described above, the high-permeability gas is separated from other substances, such as a low-permeability gas (e.g., CH4), in the mixed gas (step S22). As described above, the separation device 2 accelerates the separation of the high-permeability gas from the mixed gas because the purge gas flowing in the vicinity of the first cells 111a accelerates the permeation of the high-permeability gas through the separation membrane 12.

[0085] Here, A is assumed to be a sum of cross-sectional areas of each first cell 111a perpendicular to the longitudinal direction, B is assumed to be a sum of cross-sectional areas of each second cell 111b perpendicular to the longitudinal direction, and C is assumed to be a sum of slot opening areas of each slot 117 located at one end portion in the longitudinal direction (in the present embodiment, a sum of the areas of the six slot openings in the vicinity of the aforementioned one end portion in the longitudinal direction on the outer surface 112 of the beam 11). It is assumed that A, B, and C are expressed in the same unit. In this case, A / C is greater than or equal to 1 and less than or equal to 50, and B / C is greater than or equal to 0.5 and less than or equal to 20.When A / C is greater than or equal to 1 and less than or equal to 50, the purge gas can be supplied to the separation membrane 12 formed on the first cells 111a without any excess or deficiency. When B / C is greater than or equal to 0.5 and less than or equal to 20, the purge gas can be passed through the second cells 111b while maintaining a low pressure loss.

[0086] As described above, the number of first cell lines 116a constituting an open cell line group sandwiched between two second cell lines 116b located closest to each other in the longitudinal direction may preferably be greater than or equal to one and less than or equal to six, and may more preferably be one or two. When the number of first cell lines 116a constituting an open cell line group is greater than or equal to one and less than or equal to six, the purge gas can be efficiently supplied to the surroundings of each first cell 111a (i.e., the surroundings of the separation membrane 12).

[0087] When the number of first cell lines 116a constituting an open cell line group is one or two, each first cell 111a is adjacent to a second cell 111b or the outer surface 112 of the substrate 11. Accordingly, the purge gas can be supplied more efficiently to the vicinity of each first cell 111a (i.e., the vicinity of the separation membrane 12). As a result, the permeation of the high-permeability gas through the separation membrane 12 is further accelerated. Here, "each first cell 11a is adjacent to a second cell 111b" indicates that the first cell 111a is arranged in the vicinity of the second cell 111b without sandwiching any other first cell 111a between the second cell 111b and the second cell 111b. Furthermore, “each first cell 111a is adjacent to the outer surface 112 of the carrier 11” indicates that the first cell 111a is arranged in the vicinity of the outer surface 112 without enclosing any other first cell 111a between the outer surface 112 and the same.

[0088] As described above, since the end surfaces 114 of the support 11 are covered with the closure device 21, the separation membrane complex 1 prevents or inhibits the mixed gas containing a low-permeability gas from entering the interior of the support 11 through the end surfaces 114 and entering the separation space 220 without passing through the separation membrane 12. The gas transferred to the separation space 220 (hereinafter referred to as the "passed-through gas") is guided to the second collecting device 28 via the second discharge port 223 and collected thereby, as shown by the arrow 253 in the Fig. 7. The second collecting means 28 serves as a permeated gas collecting means that collects the gas in the mixed gas that has passed through the separation membrane 12. The permeated gas may include, in addition to the above-mentioned high-permeability gas, a low-permeability gas that has passed through the separation membrane 12.

[0089] In the mixed gas, a gas, excluding a gas that has passed through the separation membrane 12 and the support 11 (hereinafter referred to as “non-passed gas”), flows from the left side to the right side in the Fig. 7 through the first cells 111a and is passed through and collected by the first collector 27 via the first discharge port 222, as indicated by the arrow 254. The first collector 27 serves as a non-permeated gas collector that collects a non-permeated gas in the mixed gas that has not passed through the separation membrane 12. The non-permeated gas collected by the first collector 27 may include, in addition to the above-mentioned low-permeability gas, a high-permeability gas that has not passed through the separation membrane 12. For example, the non-permeated gas collected by the first collector 27 may be returned to the mixed gas supplying means 26 and supplied again into the housing 22.

[0090] In the following description, the upstream side of the flow of the mixed gas and the non-passed gas in the first cells 111a, that is, the left side in the Fig. 7, also simply referred to as the “upstream side”. The downstream side of the flow of the mixed gas and the non-passed gas in the first cells 111a, ie, the right side in the Fig. 7, is also simply referred to as the “downstream side”. In the separator 2, which is located in the Fig. As shown in Fig. 7, the purge gas is supplied to the slits 117, which are the three side flow paths on the upstream side of the separation membrane complex 1, flows in the second cells 111b from the upstream side to the downstream side, and is discharged to the separation space 220 through the three slits 117 on the downstream side of the separation membrane complex 1 (i.e., the other three side flow paths). That is, the flow direction of the purge gas in the second cell 111b is identical to the flow direction of the mixed gas and the non-permeated gas in the first cells 111a. In this way, the purge gas is supplied from the upstream side where the partial pressure of the high-permeability gas in the mixed gas is relatively high.This advantageously accelerates the permeation of the high permeability gas on the upstream side and increases the amount of the high permeability gas passing through the separation membrane 12.

[0091] In the separation membrane complex 1, the number, shape, and arrangement of the slits 117 can be modified in various ways. For example, the slits 117 do not necessarily have to open into the outer surface 112 of the support 11 on both lateral sides of the second cell lines 116b, and may open into the outer surface 112 of the support 11 only on one lateral side of the second cell line 116b. That is, a structure can be used in which the slits 117 extend from the outer surface 112 of the support 11 to the second cells 111b.

[0092] The slits 117 do not necessarily have to be formed in every second cell line 116b, and the slits 117 may be formed to penetrate only some of the second cell lines 116b. In other words, the separation membrane complex 1 may include second cell lines 116b that are not connected to the slits 117.

[0093] The slits 117 do not necessarily have to be formed on the upstream and downstream sides of the separation membrane complex 1, and for example, the slits 117 on the downstream side may be omitted. In this case, the purge gas supplied to the slits 117 on the upstream side flows from the upstream side to the downstream side through the second cells 111b and is transferred to the separation space 220 through the pores of the support 11 together with the permeated gas.

[0094] As it is in the Fig. 9, the separating device 2 may further comprise a cover 13 covering the outer surface 112 of the carrier 11. The cover 13 is an approximately cylindrical membrane-like portion or a thin plate-like portion that is in direct contact with the entire circumference of the outer surface 112 of the carrier 11 in the circumferential direction. The cover 13 is a layer that has a higher density than the carrier 11. For example, the cover 13 may be a non-porous member substantially without pores. The cover 13 is arranged between the upstream slots 117 and the downstream slots 117. In the example shown in the Fig. 9, the cover 13 is arranged between the downstream slots 117 and the sealing member 23 located in the center in the longitudinal direction of the three sealing members 23, and covers the entire outer surface 112 of the carrier 11 along approximately the entire length between the protruding sealing member 23 and the protruding slots 117.

[0095] The cover 13 may, for example, be formed from glass, ceramic, metal, or a resin. The cover 13 may, for example, be a glass membrane formed by firing on the surface of the carrier 11. For example, the cover 13 may be formed by depositing a glass frit on the surface of the carrier 11 and firing the glass frit together with the carrier 11. The formation of the cover 13 may be carried out in parallel with the formation of the separation membrane 12 (cf. the Fig. 7) or may be performed before or after the formation of the separation membrane 12. It should be noted that the material and shape of the cover 13 can be changed as appropriate. For example, the cover 13 may be formed from a resinous adhesive tape wrapped around the outer surface 112 of the support 11. Alternatively, the cover 13 may be a porous member having pores with a smaller average pore diameter than the support 11.

[0096] In this way, when the separation device 2 comprises the cover 13 covering the outer surface 112 of the carrier 11 in the separation space 220, the possibility can be limited that the purge gas flowing from the upstream slots 117 to the downstream slots 117 through the second cells 111b (see the Fig. 7), passes through the pores of the carrier 11 before reaching the downstream slots 117 and flowing out from the outer surface 112 to the separation space 220. This increases the amount of purge gas flowing in the longitudinal direction along the first cells 111a (cf. Fig. 7) and accordingly further accelerates the flow of the high permeability gas from the feed side of the separation membrane 12 to the permeate side.

[0097] As described above, the separation device 2 includes the separation membrane complex 1 and the housing 22. The separation membrane complex 1 includes the separation membrane 12 and the porous support 11. The housing 22 includes the separation membrane complex 1. The support 11 is a columnar member extending in the longitudinal direction. The support 11 includes a plurality of cells 111 arranged in a matrix in the longitudinal and lateral directions. The cells 111 include a plurality of membrane-formed cells (i.e., the first cells 111a) and a discharge cell (i.e., the second cells 111b). Each first cell 111a has both ends open in the longitudinal direction. Each of the first cells 111a has an inner surface on which the separation membrane 12 is formed. Each second cell 111b has both ends closed in the longitudinal direction. The carrier 11 has end sections in the longitudinal direction, in both of which side flow paths (ie, the slots 117) are formed extending from the outer surface 112 of the carrier 11 to the second cells 111b.

[0098] The housing 22 is connected to the mixed gas supply device 26, the passed-through gas collecting device (i.e., the second collecting device 28), the non-passed-through gas collecting device (i.e., the first collecting device 27), and the purge gas supply device 29. The mixed gas supply device 26 supplies a mixed gas containing a plurality of types of gases to the separation membrane complex 1. The second collecting device 28 collects the passed-through gas in the mixed gas that has passed through the separation membrane 12. The first collecting device 27 collects the non-passed gas in the mixed gas that has not passed through the separation membrane 12. The purge gas supply device 29 supplies the purge gas. The mixed gas is supplied to an end surface in the longitudinal direction 114 of the separation membrane complex 1. The purge gas is supplied to the slots 117 which are open into the outer surface 112 of the carrier 11.

[0099] Further, A / C is greater than or equal to 1 and less than or equal to 50, and B / C is greater than or equal to 0.5 and less than or equal to 20, where A is the sum of the cross-sectional areas of each first cell 111a perpendicular to the longitudinal direction, B is the sum of the cross-sectional areas of each second cell 111b perpendicular to the longitudinal direction, and C is the sum of the opening areas of each slit 117 located at an end portion in the longitudinal direction. Accordingly, as described above, the purge gas can be efficiently supplied to the vicinity of each first cell 111a (i.e., the vicinity of the separation membrane 12) around the plurality of first cells 111a. This accelerates the flow of the high-permeability gas from the supply side of the separation membrane 12 to the permeate side and improves the separation performance of the mixed gas separation device 2.Therefore, even if the high permeability gas in the mixed gas supplied from the mixed gas supply device 26 to the housing 22 has a relatively low partial pressure, the high permeability gas can be advantageously separated from the mixed gas.

[0100] As described above, it is preferable that the support 11 includes another side flow path (e.g., the downstream slits 117) extending from the outer surface 112 of the support 11 to the second cells 111b at a position in the longitudinal direction different from the position in the longitudinal direction of the aforementioned side flow path (e.g., the upstream slits 117). Further, it is preferable that the purge gas supplied to the slits 117 passes through the second cells 111b and the other slits 117 and can be discharged to the surroundings of the separation membrane complex 1. This increases the amount of purge gas flowing through the second cells 111b between the slits 117 and the other slits 117.In this way, by increasing the amount of purge gas flowing longitudinally along the first cells 111a, the flow of the high-permeability gas from the feed side of the separation membrane 12 to the permeate side can be further accelerated. As a result, the separation efficiency of the mixed gas separation device 2 can be further improved.

[0101] More preferably, the separation membrane complex 1 may further comprise the cover 13, which has a higher density than the support 11 and covers the outer surface 112 of the support 11 between the aforementioned slits 117 and the other slits 117. This further increases the amount of purge gas flowing in the longitudinal direction along first cells 111a, as described above, and further accelerates the flow of the high-permeability gas from the feed side of the separation membrane 12 to the permeate side. As a result, the separation performance of the mixed gas separation device 2 can be further improved.

[0102] As described above, it is preferable that each first cell 111a be adjacent to the outer surface 112 of the support 11 or a second cell 111b. This allows the purge gas to be more efficiently supplied to the vicinity of each first cell 111a (i.e., the vicinity of the separation membrane 12) around the first cells 111a. This further accelerates the flow of the high-permeability gas from the supply side of the separation membrane 12 to the permeate side and further improves the separation performance of the mixed gas separation device 2.

[0103] As described above, it is preferable that the purge gas contains at least one of H2O, air, N2, O2, and CO2. When such a gas that can be processed relatively easily is used as the purge gas, it becomes easy to process the purge gas and the permeated gas collected by the second collecting device 28 (e.g., disposing of the collected gas or separating the high-permeability gas and the purge gas).

[0104] As described above, it is preferable that the separation membrane 12 be a zeolite membrane. The separation membrane 12, composed of zeolite crystals with a uniform pore diameter, advantageously achieves selective passage of a high-permeability gas. As a result, a high-permeability gas can be efficiently separated from the mixed gas.

[0105] It is more preferable that the zeolite forming the zeolite membrane be composed of a ring with a maximum of 8 or fewer members. This more advantageously achieves the selective passage of a high-permeability gas, such as CO2, which has a relatively small molecular size. As a result, a high-permeability gas can be separated more efficiently from the mixed gas.

[0106] The separation device 2 described above is particularly suitable for use in cases where the mixed gas contains at least one or more kinds of substances from hydrogen, helium, nitrogen, oxygen, water, carbon monoxide, carbon dioxide, nitrogen oxides, ammonia, sulfur oxides, hydrogen sulfide, sulfur fluoride, mercury, arsine, hydrogen cyanide, carbonyl sulfide, C1 to C8 hydrocarbons, organic acids, alcohol, mercaptans, esters, ethers, ketone and aldehyde.

[0107] The above-described mixed gas separation method includes the step of preparing the separation membrane complex 1 comprising the separation membrane 12 and the porous support 11 (step S21), and the step of supplying a mixed gas containing a plurality of types of gases to the separation membrane 12 and allowing a high-permeability gas in the mixed gas to pass through the separation membrane 12, so that the high-permeability gas is separated from the mixed gas (step S22). The support 11 has a columnar shape extending in the longitudinal direction. The support 11 includes a plurality of cells 111 arranged in a matrix in the longitudinal and lateral directions. The cells 111 include a plurality of cells formed by a membrane (i.e., the first cells 111a) and a discharge cell (i.e., a second cell 111b). In each of the first cells 111a, both ends are open in the longitudinal direction.The separation membrane 12 is formed on the inner surface of each of the first cells 111a. Both ends in the longitudinal direction are closed for every second cell 111b. The support 11 has end portions in the longitudinal direction, in each of which a side flow path (i.e., the slits 117) is formed, extending from the outer surface 112 of the support 11 to the second cell 111b. In step S22, the mixed gas is supplied to one end surface in the longitudinal direction of the separation membrane complex 1, and the purge gas is supplied to the slits 117 open into the outer surface 112 of the support 11.

[0108] Further, A / C is greater than or equal to 1 and less than or equal to 50, and B / C is greater than or equal to 0.5 and less than or equal to 20, where A is the sum of the cross-sectional areas of each first cell 111a perpendicular to the longitudinal direction, B is the sum of the cross-sectional areas of each second cell 111b perpendicular to the longitudinal direction, and C is the sum of the opening areas of each slit 117 located at an end portion in the longitudinal direction on the outer surface 112 of the support 11. Accordingly, as described above, the purge gas can be supplied to the vicinity of each first cell 111a (i.e., the vicinity of the separation membrane 12) around the first cells 111a. This accelerates the flow of the high-permeability gas from the supply side of the separation membrane 12 to the permeate side and accelerates the separation of the mixed gas.

[0109] Next, a mixed gas separation device 2a according to a second embodiment of the present invention will be described with reference to FIG. Fig. 10. The Fig. Fig. 10 is a side view of the mixed gas separator 2a (hereinafter also referred to simply as the "separator 2a"). The structure of the separator 2a is approximately the same as that of the separator 2, except that a second supply port 224a is provided at a position opposite the second supply port 224 of the separator 2 as shown in Fig. Fig. 1, and that the three sealing elements 23 are arranged differently from those of the separating device 2. In the following description, the constituent elements of the separating device 2a that correspond to those of the separating device 2 are provided with the same reference numerals.

[0110] As it is in the Fig. 10, the second supply opening 224a is arranged between the first discharge opening 222 and the second discharge opening 223 in the longitudinal direction of the housing 22. In the example shown in the Fig. As shown in Figure 10, the second supply port 224a is located at approximately the same position in the longitudinal direction as the three downstream slots 117 of the separation membrane complex 1. The second supply port 224a may be located at the same circumferential position as the second discharge port 223 or may be located at a different circumferential position. The second supply port 224a is connected to the purge gas supply device 29.

[0111] Of the three sealing elements 23, the positions of the two sealing elements 23 located at both ends in the longitudinal direction are identical to those in the aforementioned separator 2. Of the three sealing elements 23, the sealing element 23 located between the two sealing elements 23 is located in the longitudinal direction between the second discharge port 223 and the second supply port 224a. This sealing element 23 is also located in the longitudinal direction between the second discharge port 223 and the slits 117, which are located at approximately the same position as the second supply port 224a.

[0112] The Fig. 11 is a sectional view of the separation device 2a. In the separation device 2a, the purge gas supply device 29 supplies the above-mentioned purge gas into the housing 22, as indicated by the arrow 255, in parallel with the mixed gas supply device 26, which supplies the mixed gas to the separation membrane complex 1. Specifically, the space into which the purge gas is supplied is an approximately cylindrical space located radially outward from the outer surface 112 of the separation membrane complex 1, and is also a space between the first and second sealing elements 23 from the right side of the three sealing elements 23 in the Fig. 11.

[0113] The purge gas supplied from the purge gas supply device 29 into the housing 22 flows through the downstream slots 117 of the separation membrane complex 1 into the second cells 111b, as indicated by the arrows 256a. In each second cell 111b, the purge gas flows in the Fig. 11 to the left (i.e., from the downstream side to the upstream side), as indicated by the arrows 256b. This purge gas flows through the upstream slots 117 of the separation membrane complex 1 to the separation space 220 around the separation membrane complex 1, as indicated by the arrows 256c. The separation space 220 is an approximately cylindrical space located radially outward from the outer surface 112 of the separation membrane complex 1 (i.e., around the separation membrane complex 1), and is also a space between the first and second sealing elements 23 from the left side of the three sealing elements 23 in the Fig. 11. The purge gas flowing through the second cells 111b also flows from the second cells 111b into the surrounding pores of the carrier 11 and flows from the outer surface 112 of the carrier 11 through the carrier 11 to the separation space 220.

[0114] In the separation device 2a, as in the aforementioned separation device 2, the purge gas flows to the separation space 220 around and in the vicinity of the first cells 111a. This lowers the partial pressure of a high-permeability gas on the permeate side of the separation membrane 12 (i.e., on the side opposite to the interior space of the first cells 111a) and accordingly accelerates the flow of the high-permeability gas from the supply side of the separation membrane 12 (i.e., the interior space of the first cells 111a) to the permeate side. As a result, the separation performance of the separation device 2a for the mixed gas can be improved. Accordingly, even if the high-permeability gas in the mixed gas supplied from the mixed gas supply device 26 to the housing 22 has a relatively low partial pressure, the high-permeability gas can be advantageously separated from the mixed gas.

[0115] In the separation device 2a, the purge gas is supplied to the three downstream side flow paths, i.e., the downstream slots 117, of the separation membrane complex 1, flows through the second cells 111b from the downstream side to the upstream side, and is discharged to the separation space 220 through the three upstream slots 117 (i.e., the other three side flow paths). That is, the flow direction of the purge gas in the second cells 111b is opposite to the flow directions of the mixed gas and the non-passed gas in the first cells 111a.In this way, when the purge gas is supplied from the downstream side where the high permeability gas in the mixed gas has a relatively low partial pressure, the separation membrane 12 can be enabled to function advantageously even on the downstream side and the amount of the high permeability gas passing through the separation membrane 12 can be increased.

[0116] Like the separating device 2, the separating device 2a may further comprise the above-mentioned cover 13 (see the Fig. 9) which covers the outer surface 112 of the carrier 11. When the cover 13 is arranged in the separating device 2a, as shown in the Fig. 10, the cover 13 is disposed between the upstream slits 117 and the sealing member 23 located in the center of the longitudinal direction of the three sealing members 23, and covers the entire outer surface 112 of the substrate 11 along approximately the entire length between the protruding sealing member 23 and the protruding slits 117. This further increases the amount of purge gas flowing in the longitudinal direction along the first cells 111a and accordingly further improves the separation performance of the mixed gas separator 2a as described above.

[0117] In the above description, the separators 2 and 2a are each individually arranged between the mixed gas supply device 26 and the first collecting device 27. However, for example, a plurality of separators 2 may be connected in series between the mixed gas supply device 26 and the first collecting device 27, or a plurality of separators 2a may be connected in series between the mixed gas supply device 26 and the first collecting device 27. As a further alternative, one or more separators 2 and one or more separators 2a may be connected in series between the mixed gas supply device 26 and the first collecting device 27. In this case, the order of arrangement of the separators 2 and the separators 2a may be determined appropriately.

[0118] In a mixed gas separation system 20, which is located in the Fig. 12, a separator 2 and a separator 2a are connected in series between the mixed gas supply device 26 and the first collector device 27. Specifically, the separator 2a is connected in series downstream of the separator 2. The first supply port 221 of the separator 2 is connected to the mixed gas supply device 26, and the first discharge port 222 of the separator 2 is connected to the first supply port 221 of the separator 2a. The first discharge port 222 of the separator 2a is connected to the first collector device 27. The second discharge ports 223 of the separators 2 and 2a are connected to the second collector devices 28, and the second supply ports 224 of the separators 2 and 2a are connected to the purge gas supply devices 29.

[0119] In the separator 2, which is located on the upstream side, the flow direction of the purge gas in the second cells 111b (see the Fig. 7) approximately identical to the flow directions of the mixed gas and the non-passed gas in the first cells 111a (cf. the Fig. 7). This advantageously accelerates the permeation of the high-permeability gas on the upstream side of the separation device 2 and increases the amount of the high-permeability gas passing through the separation membrane 12, as described above. In the separation device 2a located on the downstream side, the flow direction of the purge gas in the second cells 111b (see the Fig. 11) opposite to the flow directions of the mixed gas and the non-passed gas in the first cells 111a (cf. the Fig. 11). This allows the separation membrane 12 to function advantageously even on the downstream side of the separation device 2a and increases the amount of high-permeability gas passing through the separation membrane 12, as described above. As a result, the separation efficiency of the mixed-gas separation system 20 can be improved.

[0120] Next, the membrane reactor device 2b according to a third embodiment of the present invention will be described with reference to the Fig. 13. The Fig. 13 is a sectional view of the membrane reactor device 2b. The membrane reactor device 2b includes the separation device 2, which is shown in the Fig. 1, and catalysts 41 held in the separation membrane complex 1 of the separation device 2. In the following description, the separation membrane complex 1 and the catalyst 41 are also referred to together as "membrane reactor 4". To facilitate understanding of the drawing, the Fig. 13 schematically shows a section of the membrane reactor 4 in a simplified manner. Component elements of the membrane reactor device 2b that correspond to those of the separation device 2 are provided with the same reference numerals.

[0121] In the membrane reactor device 2b, a large number of catalysts 41 are arranged in the first cells 111a of the separation membrane complex 1. The catalysts 41 can have any of various shapes. Examples of the shape of the catalysts 41 include a spherical shape, an ellipsoidal shape, a cylindrical shape (e.g., a circular cylindrical shape, a prismatic shape, an oblique circular cylindrical shape, or an oblique prismatic shape), and a conical shape (e.g., a circular conical shape or a pyramidal shape). In the present embodiment, the catalysts 41 can have an approximately spherical shape. The catalysts 41 are particles with a smaller particle diameter than the first cells 111a when viewed in the longitudinal direction of the separation membrane complex 1. The catalysts 41 are a substance that accelerates chemical reactions of a raw material.In other words, chemical reactions of the starting material are accelerated in the presence of the catalysts 41. Commonly known catalysts suitable for each reaction can be used as the catalysts 41, and for example, zirconium oxide-supported nickel catalysts for methanation (i.e., catalysts with nickel (Ni) supported on stabilized zirconium oxide) can be used. The type of the catalysts 41 is not limited to this example and can be changed variously. It should be noted that the catalysts 41 are not provided in the second cells 111b.

[0122] In the membrane reactor device 2b, one or both end portions in the longitudinal direction of the first cells 111a are filled with a filling that does not close the openings of the first cells 111a to prevent or inhibit detachment of the particles of the catalysts 41 from the interior of the first cells 111a. For example, the filling may be made of a soft material, such as heat-resistant wool, and partially blocks the openings of the first cells 111a while not significantly inhibiting the passage of a gas.

[0123] Next, a method of operating the membrane reactor device 2b will be described with reference to the Fig. 14. The Fig. Figure 14 is a flowchart showing the operation of the membrane reactor device 2b. The following description is given assuming that methanation (i.e., a reaction for producing CH4 from H2 and CO2) is performed in the membrane reactor device 2b.

[0124] In the operation of the membrane reactor device 2b, the membrane reactor 4 (i.e., the separation membrane complex 1 and the catalysts 41) is first manufactured (step S31). Specifically, the membrane reactor 4 is attached to the interior of the housing 22. Then, a source gas supply device 26b supplies a source gas containing a starting material (i.e., CO2 and H2) into the housing 22 (specifically, the space on the left side of the left end face 114 of the separation membrane complex 1), as indicated by the arrow 251. The source gas may contain a gas other than the starting material. In the membrane reactor device 2b, the interior of the housing 22 is preheated, and the temperature of the membrane reactor 4 is raised to a temperature suitable for each chemical reaction of the starting material (e.g., a temperature of 150°C to 500°C). The membrane reactor 4 is maintained at this temperature during the chemical reaction of the starting material.

[0125] The purge gas supply device 29 supplies the above-mentioned purge gas into the housing 22, as indicated by the arrow 255. The purge gas flows through each upstream slot 117 into the second cells 111b, as indicated by the arrows 256a, and flows through the second cells 111b in the Fig. 13 to the right, as indicated by arrows 256b. The purge gas flows through each downstream slot 117 to the separation space 220, as indicated by arrows 256c. The purge gas flowing through the second cells 111b also flows from the second cells 111b into the surrounding pores of the carrier 11 and flows through the carrier 11 from the outer surface 112 of the carrier 11 to the separation space 220.

[0126] The source gas supplied from the source gas supply device 26b to the housing 22 flows into each first cell 111a of the separation membrane complex 1. In each first cell 111a, the starting material chemically reacts in the presence of the catalysts 41 to produce a mixed gas containing reactants (i.e., CH4 and H2O). As indicated by the arrows 252a, a high-permeability gas (i.e., H2O) in the mixed gas passes through the separation membrane 12 and the support 11 of the first cells 111a and is transferred to the separation space 220 from the outer surface 112 of the separation membrane complex 1.The high-permeability gas that has passed through the separation membrane 12 and the support 11 from the first cells 111a and flowed into the second cells 111b, as indicated by the arrows 252b, flows to the right, as indicated by the arrows 256b, together with the purge gas flowing through the second cells 111b, and flows through each downstream slit 117 to the separation space 220, as indicated by the arrows 256c. It should be noted that the high-permeability gas that flows from the first cells 111a into the second cells 111b may pass through the support 11 and be guided to the separation space 220 without passing through the slits 117. The passed gas which has been transferred to the separation space 220 is guided to and collected by the second collecting device 28 as indicated by the arrow 253 in FIG. Fig. 13. The permeated gas may further comprise, in addition to the above-mentioned high permeability gas, the source gas or a low permeability gas (ie, CH4) that has permeated through the separation membrane 12.

[0127] In the separation membrane complex 1, as described above, the purge gas flows through the second cells 111b and through the pores of the support 11 to the separation space 220. In other words, the purge gas flows to the separation space 220 around and in the vicinity of the first cells 111a. Accordingly, the high-permeability gas (i.e., H2O) that has passed through the separation membrane 12 from the first cells 111a is carried by the purge gas and rapidly transferred to the separation space 220. This reduces the partial pressure of the high-permeability gas on the permeate side of the separation membrane 12 and accelerates the flow of the high-permeability gas from the supply side of the separation membrane 12 to the permeate side. As a result, the separation of the high permeability gas from the mixed gas in the first cells 111a can be accelerated, and the chemical reaction of the starting material in the first cells 111a can be accelerated (step S32).

[0128] In the membrane reactor device 2b, a non-permeated gas in the mixed gas, excluding the permeated gas, flows through the first cells 111a from the left side to the right side in the Fig. 13 and is directed to and collected by the first collection device 27, as indicated by arrow 254. The non-permeated gas may include, in addition to the aforementioned low-permeability gas, a high-permeability gas that has not passed through the separation membrane 12. For example, the non-permeated gas collected by the first collection device 27 may be directed to the source gas supply device 26b and resupplied to the housing 22.

[0129] As described above, the membrane reactor device 2b includes the separation membrane complex 1, the catalysts 41, and the housing 22. The separation membrane complex 1 includes the separation membrane 12 and the porous support 11. The catalysts 41 accelerate chemical reactions of a starting material. The housing 22 includes the separation membrane complex 1 and the catalysts 41. The support 11 has a columnar shape extending in the longitudinal direction. The support 11 includes a plurality of cells 111 arranged in a matrix in the longitudinal and lateral directions. The cells 111 include a plurality of cells formed by a membrane (i.e., the first cells 111a) and a discharge cell (i.e., the second cell 111b). Each of the first cells 111a has open ends in the longitudinal direction. Each of the first cells 111a also has an inner surface on which the separation membrane 12 is formed.Every second cell 111b has closed ends in the longitudinal direction. The support 11 has end sections in the longitudinal direction, in both of which the side flow paths (ie, the slots 117) are formed to extend from the outer surface 112 of the support 11 to the second cells 111b. The catalysts 41 are arranged in the first cells 111a of the separation membrane complex 1.

[0130] The housing 22 is connected to the source gas supply device 26b, the passed-through gas collector (i.e., the second collector 28), the non-passed-through gas collector (i.e., the first collector 27), and the purge gas supply device 29. The source gas supply device 26b supplies a source gas containing a raw material to the separation membrane complex 1. The second collector 28 collects a passed-through gas that has passed through the separation membrane 12 into a mixed gas produced by a chemical reaction of the raw material in the presence of the catalysts 41. The first collector 27 collects a non-passed gas in the mixed gas that has not passed through the separation membrane 12. The purge gas supply device 29 supplies a purge gas. The source gas is supplied to an end face 114 in the longitudinal direction of the separation membrane complex 1.The purge gas is supplied to the slots 117 which are open into the outer surface 112 of the carrier 11.

[0131] Further, A / C is greater than or equal to 1 and less than or equal to 50, and B / C is greater than or equal to 0.5 and less than or equal to 20, where A is the sum of the cross-sectional areas of each first cell 111a perpendicular to the longitudinal direction, B is the sum of the cross-sectional areas of each second cell 111b perpendicular to the longitudinal direction, and C is the sum of the opening areas of each slit 117 located at an end portion in the longitudinal direction on the outer surface 112 of the support 11. Accordingly, as described above, the purge gas can be efficiently supplied to the environment of each first cell 111a (i.e., the environment of the separation membrane 12) around the first cells 111a. This accelerates the flow of the high-permeability gas from the supply side of the separation membrane 12 to the permeate side and accelerates the chemical reaction of the starting material in the membrane reactor device 2b.

[0132] Next, the performance of the separation membrane complex 1 in Samples 1 to 6 will be described with reference to Table 1. Samples 2 to 4 are examples of the present invention, and Samples 1, 5, and 6 are comparative examples. Table 1 Probennummer A / C B / C Druckverlust (kPa) Spülgas-Suffizienzrate (%) 1 0,8 0,4 - - 2 1,1 0,5 0,2 100 3 7,9 1,6 2,3 80 4 48,2 9,6 988 64 5 48,5 24,3 157,4 69 6 67,0 33,5 302,0 40

[0133] In Samples 1 to 6 shown in Table 1, a monolith beam 11 made of alumina and having an outer diameter of 180 mm and a length of 1000 mm was manufactured by a method similar to that disclosed in the example of International Publication No. 2010 / 134514. At this time, the number of the first cell line 116a and the length and width of the slit openings were adjusted to obtain beams 11 having A / C and B / C shown for Samples 1 to 6, respectively. It should be noted that the slits 117 having the same shape were formed in the vicinity of both end portions in the longitudinal direction of these beams 11.

[0134] Further, using a manufacturing method corresponding to the method including steps S11 to S13 described above, a DDR-type zeolite membrane (i.e., the separation membrane 12) was synthesized on the inside of the first cells 111a of the supports 11 according to Samples 2 to 6, so that the separation membrane complexes 1 were obtained. In the preparation of these supports 11, step S14 (removal of the SDA) was not performed in order to accurately measure the pressure loss described later. That is, the measurement of the pressure loss described later was performed using the DDR-type zeolite membrane through which the gas did not pass.

[0135] For support 11 in Sample 1, A / C was 0.8 and B / C was 0.4. Support 11 in Sample 1, where A / C was less than 1, could not be used for the synthesis of the DDR-type zeolite membrane due to its large slit openings and low strength.

[0136] Next, as stated in the Fig. 9, a resinous adhesive tape (i.e., the cover 13) was wound around the outer surfaces of the supports 11 of the separation membrane complex 1 in each of Samples 2 to 6, so that the supports 11 were attached to the inside of the casing 22. While the second collecting means 28 was open to the atmosphere, the pressure loss was measured by introducing a certain amount of nitrogen gas from the purge gas supply means 29 and measuring a difference in pressure between the purge gas supply means 29 and the second collecting means 28. Further, while the second collecting means 28 was open to the atmosphere, nitrogen gas at a pressure of 500 kPa was introduced from the purge gas supply means 29 to measure the amount of nitrogen gas collected by the second collecting means 28 (i.e., the amount of collected gas).For samples 2 to 6, the value obtained by dividing the amount of collected gas by the membrane area of ​​the DDR-type zeolite membrane was assumed to be a purge gas sufficiency rate (%), and the purge gas sufficiency rate in sample 2 was set as 100% to obtain the purge gas sufficiency rates for the other samples.

[0137] For carrier 11 in Sample 2, A / C was 1.1 and B / C was 0.5. The pressure drop was 0.2 kPa and the purge gas sufficiency rate was 100%, as described above. For carrier 11 in Sample 3, A / C was 7.9 and B / C was 1.6. The pressure drop was 2.3 kPa and the purge gas sufficiency rate was 80%. For carrier 11 in Sample 4, A / C was 48.2 and B / C was 9.6. The pressure drop was 98.8 kPa and the purge gas sufficiency rate was 64%.

[0138] For carrier 11 in sample 5, A / C was 48.5 and B / C was 24.3. The pressure drop was 157.4 kPa and the purge gas sufficiency rate was 69%. For carrier 11 in sample 6, A / C was 67.0 and B / C was 33.5. The pressure drop was 302.0 kPa and the purge gas sufficiency rate was 40%.

[0139] Comparing Samples 2 to 4 with Samples 5 and 6, for Samples 2 to 4, each of which had B / C greater than or equal to 0.5 and less than or equal to 20, the pressure loss values ​​were less than or equal to 100 kPa and low. For Samples 2 to 5, each of which had A / C greater than 1 and less than 50, the sweep gas sufficiency rates were higher than or equal to 60%. Thus, for Samples 2 to 4, each of which had A / C greater than or equal to 1 and less than or equal to 50 and B / C greater than or equal to 0.5 and less than or equal to 20, a sufficient amount of sweep gas could be supplied to the membrane region while keeping the pressure loss low.Therefore, the permeation of a gas to be permeated can be more efficiently accelerated when the separation of the mixed gas is performed by passing the purge gas in the separation device 2 using the separation membrane complex 1 comprising the separation membrane 12 (e.g., the DDR-type zeolite membrane manufactured by a manufacturing method corresponding to the method comprising the above-described steps S11 to S14) formed on the support 11 in any of the samples 2 to 4.

[0140] When measuring the pressure loss for Samples 2 to 6 in the same manner as described above while the resinous adhesive tape (ie, the cover 13) wound around the separation membrane complex 1 as shown in the Fig. 1 was removed, the pressure loss values ​​showed a similar trend to those shown in Table 1, but it was found that a portion of the nitrogen gas flowed through the pores of the support 11 to the second collector 28 without passing through the second cells 111b. Thus, the presence of the cover 13 on the outer surface of the support 11 helps increase the amount of purge gas flowing in the longitudinal direction along the first cells 111a.

[0141] Furthermore, when the pressure loss was measured in the same manner as described above while the resinous adhesive tape in Samples 2 to 6 was wound only around the end portions of the separation membrane complexes 1 remote from the purge gas supplying means 29 and including the slits 117, it was confirmed that the pressure loss values ​​became larger than those shown in Table 1. In this way, the presence of the slits 117 in the vicinity of the end portions in the longitudinal direction of the support 11 assists in passing the purge gas through the second cells 111b while keeping the pressure loss small.

[0142] As described above, when A / C is greater than or equal to 1 and less than or equal to 50, and B / C is greater than or equal to 0.5 and less than or equal to 20, the separation membrane complex 1 can achieve improved separation performance for the mixed gas. The separation performance for the mixed gas can be further improved, for example, by providing the slits 117 in the end portions in the longitudinal direction of the support 11 or covering the outer surface of the support 11 with the high-density cover 13.

[0143] The separation devices 2 and 2a, the mixed gas separation method and the membrane reactor device 2b described above can be modified in various ways.

[0144] For example, as in the separating device 2c shown in the Fig. 15, the length in the longitudinal direction of the cover 13 relative to that of the cover 13 of the separating device 2 shown in the Fig. 9. In the example shown in the Fig. 15, the upstream edge of the cover 13 is located in the vicinity of the upstream slots 117. In this case, the sealing element 23, which is located very close to the upstream slots 117 on the downstream side of the second supply opening 224 connected to the purge gas supply device 29, is in indirect contact with the outer surface 112 of the carrier 11 via the cover 13.

[0145] As it is in the Fig. 15, the second discharge opening 223 connected to the second collecting device 28 may be provided at approximately the same position in the longitudinal direction as the downstream slots 117. The separating device 2c may further comprise another sealing element 23 located very close to the downstream slots 117 on the upstream side of the second discharge opening 223. In this case, this sealing element 23 is in indirect contact with the outer surface 112 of the carrier 11 via the cover 13. In the separating device 2c, almost the entire amount of the gas that has passed through the separation membrane 12 flows (cf. Fig. 7), into the second cells 111b (cf. the Fig. 7) and is collected by the second collecting means 28 while flowing through the downstream slots 117 together with the purge gas. In the separation device 2c, approximately the entire outer surface 112 of the support 11 is covered by the cover 13 in a region sandwiched between two sealing members 23, excluding those of the four sealing members 23 located at both ends in the longitudinal direction. Therefore, in this region, the permeated gas and the purge gas are substantially not transferred from the outer surface 112 of the support 11 to the surroundings of the separation membrane complex 1. In the separation device 2c, the positions of the second collecting means 28 and the purge gas supply means 29 can be reversed.

[0146] In the separation membrane complex 1 of the separation device 2, which is in the Fig. As shown in Fig. 7, the zeolite constituting the separation membrane 12, which is a zeolite membrane, may be composed of a maximum of more than 8-membered ring. The separation membrane 12 is not limited to a zeolite membrane and may be an inorganic membrane such as a silica membrane or a carbon membrane, or may be an organic membrane such as a polyimide membrane or a silicone membrane. The separation membrane complex 1 may further comprise, in addition to the separation membrane 12, a functional membrane or a protective membrane laminated on the separation membrane 12. Such a functional membrane or protective membrane may be a zeolite membrane, or may be an inorganic membrane other than a zeolite membrane, or an organic membrane. The same applies to the separation devices 2a and 2c and the membrane reactor device 2b.

[0147] Of the three sealing elements 23 of the separating device 2, which are in the Fig. 7, a sealing element 23 different from those located at the ends in the longitudinal direction can allow the passage of a small amount of gas between the sealing element 23 and the outer surface 112 of the separation membrane complex 1 and between the sealing element 23 and the inner surface of the housing 22.

[0148] Chemical reactions other than methanation can take place in the membrane reactor device 2b. Examples of chemical reactions include a reverse conversion reaction, a methanol synthesis reaction, and a Fischer-Tropsch synthesis.

[0149] The structure of the preferred embodiment described above and variations can be combined in an appropriate manner as long as there are no mutual inconsistencies.

[0150] While the invention has been shown and described in detail, the foregoing description is in all aspects illustrative and not restrictive. It is therefore to be understood that numerous modifications and variations may be devised without departing from the scope of the invention. INDUSTRIAL APPLICABILITY

[0151] The separation device according to the present invention can be used, for example, for the separation of various mixed gases. The membrane reactor device according to the present invention can be used for the production of various starting materials through chemical reactions in the presence of catalysts. LIST OF REFERENCE SYMBOLS 1 Separation membrane complex 2, 2a, 2c separating device 2b Membrane reactor device 11 carriers 12 Separation membrane 13 Cover 22 housings 26 Mixed gas supply device 26b Source gas supply device 27 First collection facility 28 Second collection facility 29 Purge gas supply device 41 Catalyst 111 Cell 111a First Cell 111b Second cell 112 Exterior surface 114 End face 117 slot S11 to S14, S21 to S22, S31 to S32 Step QUOTES CONTAINED IN THE DESCRIPTION

[0000] This list of documents submitted by the applicant was generated automatically and is included solely for the convenience of the reader. This list is not part of the German patent or utility model application. The DPMA assumes no liability for any errors or omissions. Cited patent literature

[0000] JP 2022

[0002] JP 017639

[0002] WO 2016 / 104048

[0004] WO 2016 / 104049

[0004]

Claims

[1] Mixed gas separation device comprising: a separation membrane complex comprising a separation membrane and a porous support; and a housing comprising the separation membrane complex, wherein the support has a columnar shape extending in a longitudinal direction, wherein the carrier comprises a plurality of cells arranged in a matrix in a longitudinal direction and a lateral direction, wherein the plurality of cells comprises: a plurality of cells formed by a membrane, each of which has both ends open in the longitudinal direction and which has an inner surface on which the separation membrane is formed; and a delivery cell in which both ends are closed in the longitudinal direction, wherein the carrier has end portions in the longitudinal direction, in both of which a side flow path is formed which extends from an outer surface of the carrier to the discharge cell, where the housing is connected to: a mixed gas supply device that supplies a mixed gas containing a plurality of types of gases to the separation membrane complex; a permeated gas collecting means for collecting a permeated gas in the mixed gas, the permeated gas having passed through the separation membrane; a non-permeated gas collecting means for collecting a non-permeated gas in the mixed gas, the non-permeated gas not having passed through the separation membrane; and a purge gas supply device that supplies a purge gas, wherein the mixed gas is supplied to an end face in the longitudinal direction of the separation membrane complex, wherein the purge gas is supplied to the side flow path open into the outer surface of the carrier, and A / C is greater than or equal to 1 and less than or equal to 50 and B / C is greater than or equal to 0.5 and less than or equal to 20, where A is a sum of cross-sectional areas of each of the plurality of cells formed by a membrane perpendicular to the longitudinal direction; B is a sum of cross-sectional areas of each discharge cell perpendicular to the longitudinal direction; and C is a sum of opening areas of each side flow path located in one of the end portions in the longitudinal direction on the outer surface of the beam. [2] Mixed gas separation device according to claim 1, wherein the carrier further comprises another side flow path extending from the outer surface of the carrier to the discharge cell at a position in the longitudinal direction different from a position in the longitudinal direction of the side flow path, and wherein the purge gas supplied to the side flow path is discharged through the discharge cell and the further side flow path to the environment of the separation membrane complex. [3] The mixed gas separation device according to claim 2, wherein the separation membrane complex further comprises a cover having a higher density than the support and covering the outer surface of the support between the side flow path and the further side flow path. [4] A mixed gas separation device according to any one of claims 1 to 3, wherein each of the plurality of cells formed by a membrane is adjacent to the discharge cell or the outer surface of the support. [5] A mixed gas separation device according to any one of claims 1 to 4, wherein the purge gas contains at least one of water, air, nitrogen, oxygen and carbon dioxide. [6] A mixed gas separation device according to any one of claims 1 to 5, wherein the separation membrane is a zeolite membrane. [7] A mixed gas separation device according to claim 6, wherein a zeolite constituting the zeolite membrane is composed of a ring having a maximum of 8 or less members. [8] A mixed gas separation device according to any one of claims 1 to 7, wherein the mixed gas contains one or more kinds of substances of hydrogen, helium, nitrogen, oxygen, water, carbon monoxide, carbon dioxide, nitrogen oxides, ammonia, sulfur oxides, hydrogen sulfide, sulfur fluoride, mercury, hydrogen arsine, hydrogen cyanide, carbonyl sulfide, C1 to C8 hydrocarbons, organic acids, alcohol, mercaptans, esters, ethers, ketones, and aldehydes. [9] Mixed gas separation process comprising: a) preparing a separation membrane complex comprising a separation membrane and a porous support; and b) supplying a mixed gas containing a plurality of kinds of gases to the separation membrane and allowing a high-permeability gas in the mixed gas to pass through the separation membrane so that the high-permeability gas is separated from the mixed gas, wherein the support has a columnar shape extending in a longitudinal direction, wherein the carrier comprises a plurality of cells arranged in a matrix in a longitudinal direction and a lateral direction, wherein the plurality of cells comprises: a plurality of cells formed by a membrane, each of which has both ends open in the longitudinal direction and which has an inner surface on which the separation membrane is formed; and a delivery cell in which both ends are closed in the longitudinal direction, wherein the carrier has end portions in the longitudinal direction, in both of which a side flow path is formed which extends from an outer surface of the carrier to the discharge cell, wherein the process b) comprises supplying the mixed gas to an end face in the longitudinal direction of the separation membrane complex and supplying a purge gas to the side flow path open into the outer surface of the support, and A / C is greater than or equal to 1 and less than or equal to 50 and B / C is greater than or equal to 0.5 and less than or equal to 20, where A is a sum of cross-sectional areas of each of the plurality of cells formed by a membrane perpendicular to the longitudinal direction; B is a sum of cross-sectional areas of each discharge cell perpendicular to the longitudinal direction; and C is a sum of opening areas of each side flow path located in one of the end portions in the longitudinal direction on the outer surface of the beam. [10] Membrane reactor comprising: a separation membrane complex comprising a separation membrane and a porous support; a catalyst that accelerates a chemical reaction of a starting material; and a housing comprising the separation membrane complex and the catalyst, wherein the support has a columnar shape extending in a longitudinal direction, wherein the carrier comprises a plurality of cells arranged in a matrix in a longitudinal direction and a lateral direction, wherein the plurality of cells comprises: a plurality of cells formed by a membrane, each of which has both ends open in the longitudinal direction and which has an inner surface on which the separation membrane is formed; and a delivery cell in which both ends are closed in the longitudinal direction, wherein the carrier has end portions in the longitudinal direction, in both of which a side flow path is formed which extends from an outer surface of the carrier to the discharge cell, wherein the catalyst is arranged in the plurality of cells of the separation membrane complex formed by a membrane, where the housing is connected to: a source gas supply device that supplies a source gas containing a starting material to the separation membrane complex; a permeated gas collecting means for collecting a permeated gas into a mixed gas, the permeated gas having passed through the separation membrane, the mixed gas being generated by a chemical reaction of the starting material proceeding in the presence of the catalyst; a non-permeated gas collecting means for collecting a non-permeated gas in the mixed gas, the non-permeated gas not having passed through the separation membrane; and a purge gas supply device that supplies a purge gas, wherein the source gas is supplied to an end face in the longitudinal direction of the separation membrane complex, wherein the purge gas is supplied to the side flow path open into the outer surface of the carrier, and A / C is greater than or equal to 1 and less than or equal to 50 and B / C is greater than or equal to 0.5 and less than or equal to 20, where A is a sum of cross-sectional areas of each of the plurality of cells formed by a membrane perpendicular to the longitudinal direction; B is a sum of cross-sectional areas of each discharge cell perpendicular to the longitudinal direction; and C is a sum of opening areas of each side flow path located in one of the end portions in the longitudinal direction on the outer surface of the beam.

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