Gas separation module

Abstract

To provide a gas separation module which can secure both of durability and selective permeability under a high temperature condition.SOLUTION: A gas separation module 1 comprises: a first filter member 2 and a second filter member 3 that have mutually different characteristics and separate a specific gas from a mixture gas; and a housing 4 including an inflow port 51 which the mixture gas flows into, and accommodating the first filter member 2 and the second filter member 3. The first filter member 2 has characteristics superior in heat resistance to the second filter member 3. The second filter member 3 has characteristics superior in selective permeability, which makes a specific gas transmit selectively from the mixture gas, to the first filter member 2. In the housing 4, the first filter member 2 is arranged at a position closer to the inflow port 51 with respect to the second filter member 3. The second filter member 3 is arranged downstream of the first filter member 2 so that the gas which flows out of the first filter member 2 is introduced.SELECTED DRAWING: Figure 1

Description

[Technical field]

[0001] The present invention relates to a gas separation module that separates a specific gas from a mixed gas containing two or more types of gases. [Background technology]

[0002] Gas separation using gas separation membranes is becoming increasingly important as it is a method that can be achieved with energy-saving and compact equipment and is being used in a wide range of fields, including petrochemicals, chemicals, precision machinery, food, automobiles, nuclear power, and the environment. Gas separation is performed by passing the mixed gas to be separated through a gas separation module equipped with a gas separation membrane.

[0003] A gas separation module in which a filter in which a plurality of hollow fiber membranes are bundled is housed in a housing is generally known (see, for example, Patent Document 1). The hollow fiber membrane module described in Patent Document 1 is a module in which a plurality of first hollow fiber membranes and second hollow fiber membranes are bundled and packed in a cylindrical case. At both ends of the case, the first hollow fiber membrane and the second hollow fiber membrane are fixed by potting parts so that only the hollow parts are open. At both ends of the side surface side of the case, a first opening and a second opening are provided. The hollow fiber membrane module is used by being assembled in a housing having a pair of first piping connections and a pair of second piping connections. The pair of first piping connections in the housing are parts that become flow paths leading to the hollow parts of the first hollow fiber membrane and the second hollow fiber membrane, and the pair of second piping connections are parts that become flow paths leading to the outer wall surface sides of the first hollow fiber membrane and the second hollow fiber membrane through the first opening and the second opening of the case.

[0004] In the gas separation module having such a configuration, a first path is formed in which air flows from a first piping connection on one side through the hollows of the first and second hollow fiber membranes to a first piping connection on the other side, and a second path is formed in which air flows from a second piping connection on one side through a first opening of the case, through the outer wall surface sides of the first and second hollow fiber membranes, and through a second opening of the case to a second piping connection on the other side. By flowing a fluid to be dehumidified (e.g., moist gas such as water vapor or water) through one of the first and second paths and flowing a fluid to be humidified (e.g., dry gas) through the other, moisture is transmitted from one path to the other path by the membrane separation action of the first and second hollow fiber membranes.

[0005] Filters used in gas separation modules include inorganic membranes made of porous inorganic materials and polymer membranes (organic membranes) made of dense polymer materials. Inorganic membranes separate gases by allowing only molecules smaller than the micropores present in the material to pass through. On the other hand, polymer membranes separate gases based on the ease with which gas molecules dissolve or diffuse in the polymer membrane. The performance required of a filter is mainly gas separation performance (hereinafter referred to as selective permeability) and membrane durability. Polymer membranes have the advantages of being easier to manufacture and less expensive than inorganic membranes, and being able to exhibit high selective permeability for specific gas molecules through molecular design. In particular, among polymer membranes, membranes made of polyimide (polyimide membranes) are widely used as gas separation membranes that are thermally stable and have excellent mechanical properties (see, for example, Patent Document 1).

[0006] Some gas separation modules are expected to be used in a high-temperature water vapor atmosphere. For example, Patent Document 2 discloses a method for producing a hollow fiber membrane that is expected to be used in a water vapor atmosphere under high-temperature conditions of 80 to 140°C. [Prior art documents] [Patent documents]

[0007] [Patent Document 1] JP 2004-209418 A [Patent Document 2] JP 2006-255502 A Summary of the Invention [Problem to be solved by the invention]

[0008] However, when the hollow fiber membrane module described in Patent Document 1 is used in an atmosphere of high-temperature water vapor as described in Patent Document 2, there is a concern that the membrane may deteriorate and its durability may decrease due to the influence of temperature and water vapor. In particular, when a polymer membrane made of polyimide is used as the hollow fiber membrane module, there is a concern that the mechanical strength of the polymer membrane may decrease due to hydrolysis, leading to breakage and making it impossible to maintain the gas separation function.

[0009] In order to solve the problem of use under such high temperature conditions, if an attempt is made to improve the durability of the gas separation membrane by increasing its density, the gas permeability will decrease, resulting in another problem of impairing the selective permeability of the gas separation membrane. In other words, when a gas separation membrane is used under high temperature conditions, if the membrane density is increased to improve durability, the selective permeability of the membrane will decrease, whereas if the membrane density is made the same as that under normal temperature conditions to maintain the selective permeability, the durability of the membrane will decrease, resulting in a trade-off relationship.

[0010] The present invention has been made to solve the above problems, and its object is to provide a gas separation module that can achieve both durability and selective permeability under high temperature conditions. [Means for solving the problem]

[0011] The present application includes a plurality of means for solving the above problems. For example, a gas separation module includes a first filter member and a second filter member having different characteristics and separating a specific gas from a mixed gas, and a housing having an inlet through which the mixed gas flows and accommodating the first filter member and the second filter member, the first filter member having a characteristic of being more heat resistant than the second filter member, the second filter member having a characteristic of being more selectively permeable than the first filter member for selectively transmitting the specific gas from the mixed gas, the first filter member being disposed in a position closer to the inlet than the second filter member in the housing, and the second filter member being disposed downstream of the first filter member so that the gas flowing out from the first filter member is introduced. Effect of the Invention

[0012] According to the present invention, by arranging the first filter member, which has a relatively excellent heat resistance, closer to the inlet and upstream than the second filter member, gas whose effects of high temperature have been mitigated by the first filter member is introduced into the second filter member. Therefore, the second filter member is prevented from decreasing in durability due to high temperatures, and can maintain relatively excellent selective permeability performance. In other words, the gas separation module can achieve both durability and selective permeability under high temperature conditions. Problems, configurations and effects other than those described above will become apparent from the following description of the embodiments. [Brief description of the drawings]

[0013] [Figure 1] 1 is a cross-sectional view showing the configuration and structure of a gas separation module according to a first embodiment of the present invention. [Diagram 2] FIG. 2 is a schematic cross-sectional view showing the configuration and structure of a gas separation module according to a first modified example of the first embodiment of the present invention. [Diagram 3]4 is a schematic cross-sectional view showing the configuration and structure of a gas separation module according to a second modified example of the first embodiment of the present invention. FIG. [Figure 4] 5 is a cross-sectional view showing the configuration and structure of a gas separation module according to a second embodiment of the present invention. FIG. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0014] DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Hereinafter, an embodiment of a gas separation module of the present invention will be described with reference to the drawings. In this embodiment, a configuration in which a fluid (mixed gas) is supplied to the gas separation module and gas separation is performed will be described.

[0015] [First embodiment] First, the configuration and structure of a gas separation module according to a first embodiment of the present invention will be described with reference to Fig. 1. Fig. 1 is a schematic cross-sectional view showing the configuration and structure of a gas separation module according to the first embodiment.

[0016] 1, a gas separation module 1 is supplied with a mixed gas containing two or more types of gases, and separates a specific gas contained in the mixed gas from the other gases. The mixed gas supplied to the gas separation module 1 is assumed to be a high-temperature gas of about 120 to 200°C, and contains, for example, high-temperature water vapor in the range of 120 to 200°C. The gas separation module 1 includes, for example, two types of first and second filter members 2 and 3 having different characteristics, and a housing 4 that contains the first and second filter members 2 and 3.

[0017] The housing 4 is, for example, a heat-resistant and pressure-resistant cylindrical container with a bottom. The housing 4 has, for example, a cylindrical main body 41 forming an accommodation space for accommodating the first filter member 2 and the second filter member 3, a first bottom 42 closing one end (the left end in FIG. 1) of the cylindrical main body 41, and a second bottom 43 closing the other end (the right end in FIG. 1) of the cylindrical main body 41.

[0018] The first bottom 42 is provided with an inlet 51, and the second bottom 43 is provided with an outlet 52. The inlet 51 is a portion into which the mixed gas flows, and is located at the most upstream side of the gas separation module 1. The outlet 52 is a portion from which gas of the mixed gas that does not permeate the first filter member 2 and the second filter member 3 flows out.

[0019] The cylindrical main body 41 has upstream openings 53 and 54 at a portion on the inlet 51 (first bottom 42) side. The cylindrical main body 41 has downstream openings 55 and 56 at a portion on the outlet 52 (second bottom 43) side. The upstream openings 53 and 54 are configured as outlets that guide the gas that has permeated the first filter member 2 to the outside of the housing 4, and the downstream openings 55 and 56 are configured as outlets that guide the gas that has permeated the second filter member 3 to the outside of the housing 4. The upstream openings 53 and 54 and the downstream openings 55 and 56 can also be configured to be provided in multiple numbers in the circumferential direction of the cylindrical main body 41. The upstream openings 53 and 54 and the downstream openings 55 and 56 can also be configured to have only one opening, respectively.

[0020] The first filter member 2 is, for example, a bundle of a number of hollow fiber-shaped membranes 21 (hereinafter referred to as hollow fiber membranes). The first filter member 2 is configured such that the bundled hollow fiber membranes 21 extend in the axial direction (left-right direction in FIG. 1) of the cylindrical main body 41 of the housing 4. In the first filter member 2, both ends (left and right in FIG. 1) of the bundled hollow fiber membranes 21 are fixed to the cylindrical main body 41 by fixing parts 6a, 6b (hereinafter, the fixing parts 6a, 6b at both ends may be collectively referred to as fixing parts 6). The fixing parts 6 are formed by filling the gaps between the hollow fiber membranes 21 and the cylindrical main body 41 with a thermosetting resin such as an epoxy resin or a urethane resin and solidifying it. The fixing parts 6 seal the gaps between both side ends of the first filter member 2 and the cylindrical main body part 41 while keeping the hollow parts of the numerous hollow fiber membranes 21 of the first filter member 2 connected without blocking them.

[0021] The second filter member 3 is, for example, similar to the first filter member 2, a bundle of a large number of hollow fiber membranes 31, and is configured so that the bundled large number of hollow fiber membranes 31 extend in the axial direction of the cylindrical main body 41 of the housing 4. In the second filter member 3, both ends (left and right in FIG. 1) of the bundled large number of hollow fiber membranes 31 are fixed to the cylindrical main body 41 by fixing parts 7a, 7b (hereinafter, the fixing parts 7a, 7b at both ends may be collectively referred to as fixing parts 7). The fixing parts 7 are formed by filling the gaps between the large number of hollow fiber membranes 31 and the cylindrical main body 41 with a thermosetting resin such as epoxy resin or urethane resin and solidifying it. The fixing parts 7 seal the gaps between both ends of the second filter member 3 and the cylindrical main body 41 while communicating the hollow parts of the large number of hollow fiber membranes 31 of the second filter member 3 without blocking them.

[0022] The first filter member 2 has a property (hereinafter referred to as selective permeability) of selectively allowing a specific gas from a mixed gas to pass therethrough while not allowing gas with a molecular size (dynamic molecular diameter) larger than that of the specific gas to pass therethrough. The first filter member 2 has a property of selectively allowing water vapor and hydrogen gas to pass therethrough while not allowing gas with a molecular size (dynamic molecular diameter) larger than that of water vapor and hydrogen gas to pass therethrough.

[0023] The first filter member 2 further has a characteristic of being more heat resistant than the second filter member 3. Specifically, the first filter member 2 is made of a material that does not deteriorate due to hydrolysis even under high-temperature water vapor in the range of 120 to 200°C. Examples of such materials include a polymer film that does not contain an ester bond, an inorganic film mainly composed of an inorganic material such as ceramics, and a graphene film mainly composed of carbon. Examples of polymer films that do not contain an ester bond include those formed from materials such as PPS (polyphenylene sulfide), PF (phenolic resin), PBT (polybutylene terephthalate), PVDC (polyvinylidene chloride), and PDAP (allyl resin, diallyl phthalate).

[0024] The second filter member 3 has a characteristic that it is inferior in heat resistance to the first filter member 2, but is superior in selective permeability to the first filter member 2. The second filter member 3 is superior to the first filter member 2 in selective permeability, for example, in that it selectively transmits water vapor and hydrogen gas, while not transmitting gases with molecular sizes larger than water vapor and hydrogen gas. Specifically, the second filter member 3 transmits gases with a kinetic molecular diameter of 0.3 nanometers (nm) or less, while not transmitting gases with a kinetic molecular diameter larger than that. An example of such a member is a polymer membrane formed of a material mainly composed of polyimide. While the polymer membrane has excellent selective permeability to water vapor and hydrogen gas, there is a concern that it may deteriorate due to hydrolysis under high-temperature water vapor.

[0025] In the gas separation module 1, the gaps between both side ends of the first filter member 2 and the cylindrical main body 41 are sealed by the fixing parts 6a and 6b, and the gaps between both side ends of the second filter member 3 and the cylindrical main body 41 are sealed by the fixing parts 7a and 7b. As a result, the flow path through which the mixed gas flows, the flow path through which the gas that has permeated the first filter member 2 flows, and the flow path through which the gas that has permeated the second filter member 3 flows are completely separated. That is, in the gas separation module 1, the mixed gas is prevented from flowing outside the hollow fiber membranes 21 and 31 of the first filter member 2 and the second filter member 3, and flows only through the hollow parts of the hollow fiber membranes 21 and 31, and specific gases (water vapor and hydrogen gas) permeate from the inside to the outside of the hollow fiber membranes 21 and 31, thereby performing gas separation.

[0026] The first filter member 2 and the second filter member 3 are arranged in series in this order with respect to the flow of the mixed gas in the cylindrical main body 41 of the housing 4. In detail, the first filter member 2 is arranged at a position closer to the inlet 51 than the second filter member 3, and is located at a front stage on the upstream side of the second filter member 3 with respect to the flow of the mixed gas. On the other hand, the second filter member 3 is arranged at a position farther from the inlet 51 and closer to the outlet 52 than the first filter member 2, and is located at a rear stage on the downstream side of the first filter member 2 with respect to the flow of the mixed gas. That is, the second filter member 3 is arranged downstream of the first filter member 2 so that the gas (mixed gas) flowing out from the first filter member 2 is introduced. The second filter member 3 is configured so that the upstream openings 53 and 54 are located at a portion of the cylindrical main body 41 corresponding to the arrangement position of the first filter member 2. The second filter member 3 is configured so that the downstream openings 55 and 56 are located at a portion of the cylindrical main body 41 corresponding to the arrangement position of the second filter member 3.

[0027] In the gas separation module 1, the mixed gas flowing in from the inlet 51 of the housing 4 passes through the first filter member 2 and then flows into the second filter member 3. In other words, the gas separation module 1 is configured to prevent the mixed gas from bypassing the first filter member 2 and flowing directly into the second filter member 3.

[0028] Next, the function and effect of the gas separation module according to the first embodiment will be described with reference to Fig. 1. Here, the description will be given taking as an example a case in which the mixed gas under high temperature conditions contains high temperature and high pressure water vapor.

[0029] A mixed gas containing high-temperature and high-pressure water vapor is supplied into the housing 4 through the inlet 51 of the gas separation module 1 (see the outline arrow). The mixed gas that has flowed into the cylindrical main body 41 of the housing 4 is first introduced into and passes through the hollow parts of the multiple hollow fiber membranes 21 of the first filter member 2 located at the upstream front stage. At this time, water vapor and hydrogen gas selectively permeate from the hollow parts of the hollow fiber membranes 21 to the outside of the membrane and flow out of the housing 4 through the upstream openings 53, 54 (see the dashed arrow). However, not all of the water vapor and hydrogen gas contained in the mixed gas permeates through the first filter member 2. The amount of permeation changes depending on various conditions such as the fluid speed and fluid pressure flowing through the hollow fiber membranes 21 and the diameter of the hollow fiber membranes 21. On the other hand, of the mixed gas, water vapor and hydrogen gas that are not transmitted through the first filter member 2, as well as gases with a larger dynamic molecular diameter than water vapor and hydrogen gas, pass through the hollow portion of the hollow fiber membrane 21 and then reach the second filter member 3 located at the rear downstream side (see the white arrow).

[0030] The mixed gas that has not been permeated through the first filter member 2 and has reached the second filter member 3 is introduced into and passes through the hollow parts of a number of hollow fiber membranes 31. At this time, water vapor and hydrogen gas selectively permeate from the hollow parts of the hollow fiber membranes 31 to the outside of the membrane and flow out of the housing 4 through the downstream openings 55, 56 (see the dashed arrows). Here, too, not all of the water vapor and hydrogen gas remaining in the mixed gas permeates through the second filter member 3. On the other hand, the water vapor and hydrogen gas that have not been permeated through the second filter member 3, and gases with a larger dynamic molecular diameter than the water vapor and hydrogen gas, pass through the hollow parts of the hollow fiber membranes 31 and then flow out of the housing 4 through the outlet 52 of the housing 4 (see the open arrow).

[0031] In this embodiment, the first filter member 2 having excellent heat resistance is disposed on the upstream side at a position closer to the inlet 51 than the second filter member 3. As a result, the high-temperature, high-pressure mixed gas first flows into the first filter member 2 on the upstream side, and therefore the high-temperature, high-pressure mixed gas does not flow directly into the second filter member 3.

[0032] The object into which the high-temperature, high-pressure mixed gas first flows into the housing 4 will have the highest temperature and will be most affected by the temperature. In other words, the first filter member 2 will be most affected by the high temperature of the mixed gas. In contrast, by constructing the first filter member 2 from a material with excellent heat-resistant properties, even if it is affected by the high temperature of the mixed gas, degradation due to high temperatures is minimal, and the durability of the filter can be maintained.

[0033] On the other hand, since the mixed gas that has passed through the first filter member 2 (the hollow portion of the hollow fiber membrane 21) flows into the second filter member 3, the effect of the high temperature of the mixed gas is mitigated by the first filter member 2. Therefore, even the second filter member 3, which has relatively poor heat resistance, can suppress deterioration due to the temperature of the mixed gas. Therefore, the selective permeability performance of the second filter member 3, which has excellent selective permeability, can be maintained.

[0034] In this embodiment, when the mixed gas passes through the first filter member 2 or passes through without passing through, the heat of the mixed gas is dissipated to the outside of the housing 4 via the cylindrical main body 41. Therefore, the mixed gas passing through the hollow part of the hollow fiber membrane 21 without passing through the first filter member 2 has a temperature distribution in which the temperature gradually decreases in the flow direction, and the mixed gas at a temperature lower than the temperature on the inlet 51 side (upstream side) of the first filter member 2 is introduced into the second filter member 3. As a result, the rate at which the durability of the second filter member 3 decreases is suppressed, and the shortening of the life of the second filter member 3 due to the temperature can be avoided.

[0035] In this embodiment, upstream openings 53, 54 that communicate the inside and outside of the cylindrical main body 41 are provided in a region of the cylindrical main body 41 of the housing 4 corresponding to the arrangement position of the first filter member 2. That is, the upstream openings 53, 54 are provided in the housing 4 for discharging the gas that has permeated the first filter member 2 to the outside of the housing 4. As a result, the water vapor and hydrogen gas that have permeated the first filter member 2 are discharged to the outside of the housing 4 through the upstream openings 53, 54, and the partial pressure of the water vapor acting on the second filter member 3 is reduced. This suppresses deterioration of the durability of the second filter member 3 due to the pressure.

[0036] In this embodiment, the first filter member 2, which has relatively excellent heat resistance, is first affected by the high temperature and pressure of the mixed gas, thereby mitigating the effect of high temperature on the second filter member 3, so that a configuration can be adopted in which a material with excellent selective permeability properties, even if it has relatively poor heat resistance properties, is used as the second filter member 3. This allows the gas separation module 1 to achieve both durability against high temperatures and high pressures and selective permeability.

[0037] The gas separation module 1 according to the first embodiment described above includes a first filter member 2 and a second filter member 3 having different characteristics and separating a specific gas from a mixed gas, and a housing 4 having an inlet 51 through which the mixed gas flows and accommodating the first filter member 2 and the second filter member 3. The first filter member 2 has a characteristic of being more heat resistant than the second filter member 3, and the second filter member 3 has a characteristic of being more selectively permeable than the first filter member 2, which selectively allows a specific gas to pass through from the mixed gas. In the housing 4, the first filter member 2 is disposed at a position closer to the inlet 51 than the second filter member 3. The second filter member 3 is disposed downstream of the first filter member 2 so that the gas flowing out from the first filter member 2 is introduced therein.

[0038] According to this configuration, by arranging the first filter member 2, which has relatively excellent heat resistance, closer to the inlet 51 and on the upstream side than the second filter member 3, gas whose effects of high temperature have been mitigated by the first filter member 2 is introduced into the second filter member 3. As a result, the second filter member 3 is prevented from suffering a decrease in durability due to high temperatures, and can maintain relatively excellent selective permeability performance. In other words, the gas separation module 1 can achieve both durability and selective permeability under high temperature conditions.

[0039] In addition, in this embodiment, the housing 4 has upstream openings 53, 54 (openings) that guide a specific gas (e.g., water vapor) separated from the mixed gas by the first filter member 2 to the outside of the housing 4.

[0040] According to this configuration, the specific gas that has passed through the first filter member 2 flows out of the housing 4 through the upstream openings 53, 54 (openings) of the housing 4, thereby reducing the partial pressure of the specific gas contained in the mixed gas acting on the second filter member 3 located downstream, thereby suppressing deterioration of the durability of the second filter member 3 against pressure.

[0041] In addition, in this embodiment, the second filter member is made of a material that is permeable to gases with a kinetic molecular diameter of 0.3 nanometers or less, but is not permeable to gases with a kinetic molecular diameter larger than that.

[0042] With this configuration, the second filter member 3 can reliably separate water vapor and hydrogen gas from the mixed gas.

[0043] [First Modification of the First Embodiment] Next, a gas separation module according to a first modified example of the first embodiment will be described with reference to Fig. 2. Fig. 2 is a schematic cross-sectional view showing the configuration and structure of a gas separation module according to a first modified example of the first embodiment. In Fig. 2, the same reference numerals as those in Fig. 1 denote similar parts, and therefore detailed descriptions thereof will be omitted.

[0044] A gas separation module 1A according to a first modification of the first embodiment shown in Fig. 2 differs from the gas separation module 1 according to the first embodiment (see Fig. 1) in that the upstream openings 53, 54 (see Fig. 1) of the first embodiment are not provided in the cylindrical main body 41A of the housing 4A. That is, the housing 4A is configured such that the cylindrical main body 41A does not have an opening as an outlet for guiding a specific gas (e.g., water vapor and hydrogen gas) that permeates the first filter member 2 to the outside of the housing 4A. Other configurations of the first modification of the first embodiment are similar to those of the first embodiment.

[0045] In this first modified example, the high-temperature and high-pressure mixed gas flowing into the cylindrical main body 41 through the inlet 51 of the housing 4A is introduced and passes through the hollow parts of the multiple hollow fiber membranes 21 of the first filter member 2 located in the upstream front stage, as in the first embodiment (see the outline arrow). In this configuration, unlike the first embodiment, the entire amount of the mixed gas passes through the hollow parts of the hollow fiber membranes 21 to reach and be introduced into the second filter member 3 located in the rear stage. For this reason, there is no partial pressure drop due to the outflow of a specific gas from the first filter member 2 to the outside of the housing 4 as in the first embodiment. In other words, the pressure of the mixed gas acting on the second filter member 3 only drops by the amount of pressure loss when it flows through the first filter member 2.

[0046] However, even if the first filter member 2 is damaged by continued exposure to the high temperature and high pressure of the mixed gas, the mixed gas flowing through the first filter member 2 will not flow out of the housing 4 through the damaged part of the first filter member 2, but will be introduced into the second filter member 3. This maintains the gas separation function of the gas separation module 1A, thereby achieving a fail-safe for the first filter member 2, which is most susceptible to the effects of high temperatures.

[0047] According to the first modification of the first embodiment described above, similarly to the first embodiment, the first filter member 2, which has relatively excellent heat resistance, is disposed closer to the inlet 51 and upstream than the second filter member 3, so that the gas whose effects of high temperature have been mitigated by the first filter member 2 is introduced into the second filter member 3. As a result, the second filter member 3 is prevented from decreasing in durability due to high temperatures, and can maintain relatively excellent selective permeability performance. In other words, the gas separation module 1A can achieve both durability and selective permeability under high temperature conditions.

[0048] Furthermore, in the gas separation module 1A of this first modified example, the housing 4A is configured to accommodate the first filter member 2 without providing an opening for directing the specific gas separated from the mixed gas by the first filter member 2 to the outside of the housing 4A.

[0049] According to this configuration, even if the first filter member 2 on the upstream side is damaged, the mixed gas is introduced into the second filter member 3 on the downstream side without flowing out of the housing 4 from the damaged part of the first filter member 2, thereby maintaining the gas separation function of the gas separation module 1A and achieving a fail-safe function of the gas separation module 1A.

[0050] [Second Modification of the First Embodiment] Next, a gas separation module according to a second modified example of the first embodiment will be described with reference to Fig. 3. Fig. 3 is a schematic cross-sectional view showing the configuration and structure of a gas separation module according to a second modified example of the first embodiment. In Fig. 3, the same reference numerals as those in Figs. 1 and 2 denote similar parts, and therefore detailed descriptions thereof will be omitted.

[0051] The gas separation module 1B according to the second modification of the first embodiment shown in FIG. 3 is different from the gas separation module 1 according to the first embodiment (see FIG. 1) in that the first filter member 2B arranged in the cylindrical main body 41B of the housing 4B is longer than the second filter member 3, and the axial length of the cylindrical main body 41B is longer accordingly. Specifically, the first filter member 2B is configured so that the length in the extension direction of the hollow fiber membranes 21, 31 is longer than the second filter member 3. That is, the length L1 of the first filter member 2B in the flow direction of the mixed gas is set to be longer than the length L2 of the second filter member 3 in the flow direction of the mixed gas (L1>L2). The cylindrical main body 41B is also configured so that the total length is longer than the cylindrical main body 41 according to the first embodiment in accordance with the extension of the first filter member 2B. The other configurations of the second modification of the first embodiment are similar to those of the first embodiment.

[0052] In the second modified example, when the mixed gas flows through the first filter member 2B, the heat of the mixed gas is dissipated to the outside of the housing 4B through the cylindrical main body 41B. Therefore, the mixed gas passing through the hollow part of the hollow fiber membrane 21 without passing through the first filter member 2B has a temperature distribution in which the temperature gradually decreases in the flow direction, and the mixed gas having a temperature lower than the temperature on the inlet 51 side (upstream side) of the housing 4B is introduced into the second filter member 3. As a result, the deterioration rate of the durability of the second filter member 3 is suppressed, and it is possible to avoid the shortening of the life of the second filter member 3 due to the temperature. In particular, since the first filter member 2B is longer in the flow direction of the mixed gas than the first filter member 2 of the first embodiment, the effect of dissipating the heat of the mixed gas to the outside of the housing 4B is increased accordingly. Therefore, since the temperature of the mixed gas introduced into the second filter member 3 is lower than that in the first embodiment, the deterioration rate of the durability of the second filter member 3 is further suppressed.

[0053] According to the second modification of the first embodiment described above, similarly to the first embodiment, the first filter member 2B, which has a relatively excellent heat resistance, is disposed closer to the inlet 51 and upstream than the second filter member 3, so that the gas whose effect of high temperature has been mitigated by the first filter member 2B is introduced into the second filter member 3. Therefore, the second filter member 3 is prevented from decreasing in durability due to high temperatures, and can maintain relatively excellent selective permeability performance. In other words, the gas separation module 1B can achieve both durability and selective permeability under high temperature conditions.

[0054] In the gas separation module 1B according to the second modified example, the first filter member 2B and the second filter member 3 are each composed of a plurality of hollow fiber membranes 21, 31. The first filter member 2B is configured so that the length in the extension direction of the hollow fiber membranes 21, 31 is longer than that of the second filter member 3.

[0055] According to this configuration, since the length of the first filter member 2B is long, the effect of dissipating heat of the mixed gas to the outside via the housing 4B when the mixed gas flows through the first filter member 2B is enhanced. Therefore, the temperature of the mixed gas introduced into the second filter member 3 becomes lower, and the durability life of the second filter member 3 against temperature can be extended.

[0056] [Second embodiment] Next, a gas separation module according to a second embodiment of the present invention will be described with reference to Fig. 4. Fig. 4 is a schematic cross-sectional view showing the configuration and structure of a gas separation module according to the second embodiment. In Fig. 4, the same reference numerals as those shown in Figs. 1 to 3 denote similar parts, and therefore detailed description thereof will be omitted.

[0057] The main difference between the gas separation module 1C of the second embodiment shown in Figure 4 and the gas separation module 1 of the first embodiment (see Figure 1) is that the configurations of the first filter member 2C and the second filter member 3C are different, and therefore the configuration of the housing 4C is also different.

[0058] Specifically, the first filter member 2C and the second filter member 3C are not made of hollow fiber membranes but are film-type filter members. The first filter member 2C has a number of film-type membranes 22 arranged in series in the axial direction of the cylindrical main body 41C. The second filter member 3C, like the first filter member 2C, has a number of film-type membranes 32 arranged in series in the axial direction of the cylindrical main body 41C.

[0059] The first filter member 2C, like the first embodiment, has a characteristic of selectively passing water vapor and hydrogen gas, while not passing gases having a larger kinetic molecular diameter than water vapor and hydrogen gas. The first filter member 2C, like the first embodiment, has a characteristic of being more heat resistant than the second filter member 3C. The second filter member 3C, like the first embodiment, has a characteristic of being less heat resistant than the first filter member 2C, but more selectively permeable than the first filter member 2C. That is, the second filter member 3C selectively passes water vapor and hydrogen gas, while the selective permeability of not passing gases having a larger kinetic molecular diameter than water vapor and hydrogen gas is superior to that of the first filter member 2C.

[0060] The housing 4C has a cylindrical main body 41C forming an accommodation space for accommodating the first filter member 2C and the second filter member 3C, a first bottom 42C closing one end (left end in FIG. 4) of the cylindrical main body 41C, and a second bottom 43C closing the other end (right end in FIG. 4) of the cylindrical main body 41C. An inlet 51C through which the mixed gas flows is provided on the first bottom 42C side of the cylindrical main body 41C. The inlet 51C is a portion located at the most upstream of the gas separation module 1C. An outlet 52C is provided on the opposite side of the inlet 51C on the first bottom 42C side of the cylindrical main body 41C to guide the gas that does not permeate the first filter member 2C and the second filter member 3C out of the mixed gas to the outside of the housing 4C. A downstream opening 55C, which is an outlet for guiding the gas permeating the first filter member 2C and the second filter member 3C to the outside of the housing 4C, is provided on the second bottom 43C side of the cylindrical main body 41C. That is, the housing 4C is configured so that the gas permeating the first filter member 2C and the second filter member 3C flows along the axial direction of the cylindrical main body 41C, while the mixed gas that does not permeate the first filter member 2C and the second filter member 3C flows at one end of the cylindrical main body 41C on the first bottom 42 side.

[0061] In the gas separation module 1C, the first filter member 2C and the second filter member 3C are arranged in series in this order in the cylindrical main body 41C from the first bottom 42 side to the second bottom 43 side of the cylindrical main body 41C. In detail, the first filter member 2C is arranged at a position closer to the inlet 51C than the second filter member 3C, and is located at a front stage on the upstream side of the second filter member 3C with respect to the flow of gas along the axial direction of the cylindrical main body 41C. On the other hand, the second filter member 3C is arranged at a position farther from the inlet 51C than the first filter member 2C and closer to the downstream opening 55C, and is located at a rear stage on the downstream side of the first filter member 2C with respect to the flow of gas along the axial direction of the cylindrical main body 41C. That is, the second filter member 3C is arranged downstream of the first filter member 2C so that the gas (permeated gas) flowing out from the first filter member 2C is introduced.

[0062] In the gas separation module 1C according to the present embodiment, the mixed gas flowing into the cylindrical main body 41C via the inlet 51 of the housing 4C is first introduced into the first filter member 2, and a specific gas separated from the mixed gas by the first filter member 2 is introduced into the second filter member 3. In other words, the gas separation module 1C is configured to prevent the mixed gas from bypassing the first filter member 2C and flowing directly into the second filter member 3C.

[0063] In this embodiment, the high-temperature, high-pressure mixed gas (see the white arrow) supplied into the housing 4C through the inlet 51C of the gas separation module 1C is first introduced into the first filter member 2C located at the front stage on the upstream side. The water vapor and hydrogen gas contained in the mixed gas are selectively permeated by the multiple membranes 22 of the first filter member 2C and introduced into the second filter member 3C on the downstream side (see the dashed arrow). The water vapor and hydrogen gas introduced into the second filter member 3C and permeated through the multiple membranes 32 flow out to the outside of the housing 4C through the downstream opening 55C (see the dashed arrow). On the other hand, the water vapor and hydrogen gas not permeated by the first filter member 2C and the gas with a larger dynamic molecular diameter than the water vapor and hydrogen gas are introduced into the outlet 52C (see the white arrow).

[0064] In this embodiment, as in the first embodiment, the first filter member 2C having excellent heat resistance is disposed upstream at a position closer to the inlet 51C than the second filter member 3C. As a result, the high-temperature, high-pressure mixed gas first flows into the first filter member 2C on the upstream side, and the high-temperature, high-pressure mixed gas does not directly flow into the second filter member 3C. By forming the first filter member 2C from a member having excellent heat resistance, even if it is affected by the high temperature of the mixed gas, deterioration due to high temperatures is reduced, and the durability of the filter can be maintained.

[0065] On the other hand, the second filter member 3C is introduced with the specific gas (water vapor and hydrogen gas) that has permeated through the first filter member 2C, and the effect of the high temperature of the mixed gas is mitigated by the first filter member 2C. Therefore, even the second filter member 3C, which has relatively poor heat resistance, can suppress deterioration due to the temperature of the specific gas. Therefore, the selective permeability performance of the second filter member 3C, which has excellent selective permeability, can be maintained.

[0066] In this embodiment, the first filter member 2C, which has relatively excellent heat resistance, is first affected by the high temperature and pressure of the mixed gas, thereby mitigating the effect of high temperature on the second filter member 3C, so that a configuration using a material with excellent selective permeability properties even if it has relatively poor heat resistance properties can be adopted as the second filter member 3C. This allows the gas separation module 1C to achieve both durability against high temperatures and high pressures and selective permeability.

[0067] According to the gas separation module 1C of the second embodiment described above, as in the first embodiment, the first filter member 2C, which has relatively excellent heat resistance, is disposed closer to the inlet 51C and upstream than the second filter member 3C, so that the gas whose effect of high temperature is mitigated by the first filter member 2C is introduced into the second filter member 3C. Therefore, the second filter member 3C is prevented from decreasing in durability due to high temperatures, and can maintain relatively excellent selective permeability performance. In other words, the gas separation module 1C can achieve both durability and selective permeability under high temperature conditions.

[0068] [Other embodiments] The present invention is not limited to the above-mentioned first and second embodiments and their modifications, but includes various modifications. The above-mentioned embodiments have been described in detail to easily explain the present invention, and are not necessarily limited to those having all the configurations described. For example, it is possible to replace a part of the configuration of one embodiment with the configuration of another embodiment, and it is also possible to add the configuration of another embodiment to the configuration of one embodiment. It is also possible to add, delete, or replace a part of the configuration of each embodiment with another configuration.

[0069] For example, in the above-mentioned first and second embodiments and their modifications, the first filter members 2, 2B, and 2C and the second filter members 3 and 3C are configured to separate water vapor and hydrogen from a mixed gas. However, the first filter member and the second filter member only need to be capable of separating at least one specific gas from a mixed gas containing two or more types of gases.

[0070] In the above-mentioned first embodiment and its modified example, one fluid (mixed gas) is supplied to the gas separation module 1, 1A, 1B to perform gas separation. However, a configuration in which two fluids are supplied to the gas separation module 1, 1A, 1B to perform gas separation is also possible. Specifically, in the gas separation module 1, 1A, 1B, for example, the fluid to be dehumidified as a mixed gas is supplied through the inlet 51 of the housing 4, 4A, 4B, and the fluid to be humidified is supplied through one of the upstream opening 53 and downstream opening 55 of the housing 4, 4A, 4B. As a result, the fluid to be dehumidified passes through the hollow parts of the first filter member 2, 2B and the second filter member 3 and flows out through the outlet 52 of the housing 4, 4A, 4B, and the moisture of the fluid to be dehumidified permeates the first filter member 2, 2B and the second filter member 3 to merge with the fluid to be humidified. The fluid to be humidified flows into the housing 4, 4A, 4B through one of the upstream opening 53 and downstream opening 55, and flows out through the other upstream opening 54 and downstream opening 56 together with moisture that has permeated the first filter member 2, 2B and second filter member 3. [Explanation of symbols]

[0071] 1, 1A, 1B, 1C... gas separation module; 2, 2B, 2C... first filter member; 3, 3C... second filter member; 4, 4A, 4B, 4C... housing; 21... hollow fiber membrane; 31... hollow fiber membrane; 51, 51C... inlet; 53, 54... upstream opening (opening)

Claims

1. a first filter member and a second filter member having different characteristics and configured to separate a specific gas from a mixed gas; a housing having an inlet through which the mixed gas flows and accommodating the first filter member and the second filter member; the first filter member has a characteristic of being more heat resistant than the second filter member; the second filter member has a characteristic of selectively transmitting the specific gas from the mixed gas more excellent than that of the first filter member; The first filter member is disposed in the housing at a position closer to the inlet than the second filter member, The second filter member is disposed downstream of the first filter member so that gas flowing out from the first filter member is introduced into the second filter member. A gas separation module comprising:

2. 2. The gas separation module of claim 1, The housing has an opening for guiding the specific gas separated from the mixed gas by the first filter member to the outside of the housing. A gas separation module comprising:

3. 2. The gas separation module of claim 1, The housing is configured to accommodate the first filter member without providing an opening for guiding the specific gas separated from the mixed gas by the first filter member to the outside of the housing. A gas separation module comprising:

4. 2. The gas separation module of claim 1, The first filter member and the second filter member are each composed of a plurality of hollow fiber membranes, The first filter member is configured to have a length in the extending direction of the hollow fiber membrane longer than that of the second filter member. A gas separation module comprising:

5. 2. The gas separation module of claim 1, The second filter member is made of a material that allows gases with a kinetic molecular diameter of 0.3 nanometers or less to pass through, but does not allow gases with a kinetic molecular diameter larger than that to pass through. A gas separation module comprising:

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