Hollow fiber membrane module

Abstract

A hollow fiber membrane module 10 comprises: an outer case 100; an inner case 200; a hollow fiber membrane bundle 300 composed of a plurality of hollow fiber membranes filled in an annular gap between the outer case 100 and the inner case 200; a first sealing part 410; and a second sealing part 420, the hollow fiber membrane module 10 having formed therein a membrane exterior passage, which passes from an opening in the inner case 200, through a first through hole 230, past the exteriors of the plurality of hollow fiber membranes, and to a second through hole 130, and, and a membrane interior passage, which passes through the interiors of the plurality of hollow fiber membranes, said hollow fiber membrane module 10 being characterized in that a cylindrical member 500 having a plurality of third through-holes 510 that form a part of the membrane exterior passage is provided between the hollow fiber membrane bundle 300 and the outer case 100.

Description

Hollow fiber membrane module

[0001] The present invention relates to a hollow fiber membrane module.

[0002] A humidifier used in a fuel cell is equipped with a hollow fiber membrane module. A conventional hollow fiber membrane module 700 will be described with reference to Fig. 8. Fig. 8 is a schematic cross-sectional view of a conventional hollow fiber membrane module.

[0003] The hollow fiber membrane module 700 includes an outer case 710, an inner case 720 disposed inside the outer case 710, and a hollow fiber membrane bundle 730 consisting of a plurality of hollow fiber membranes filled in the annular gap between the outer case 710 and the inner case 720. The plurality of hollow fiber membranes have first and second sealing portions 741 and 742 at both ends, sealing the gaps between the plurality of hollow fiber membranes while leaving the hollow interiors of each hollow fiber membrane open.

[0004] The inner case 720 is provided with a first through-hole 721, and the outer case 710 is provided with a second through-hole 711. This forms an extra-membrane passage (see arrow A) that runs from the opening of the inner case 720 through the first through-hole 721, past the outside of the hollow fiber membranes, and to the second through-hole 711. An intra-membrane passage (see arrow B) that runs through the inside of the hollow fiber membranes is also formed. This allows, for example, wet gas to flow through the extra-membrane passage and dry gas to flow through the intra-membrane passage, thereby drying the wet gas and humidifying the dry gas. In this way, the hollow fiber membrane module 700 can humidify dry gas, and is used as a humidifier for fuel cells.

[0005] In the hollow fiber membrane module 700 configured as described above, the gas flowing through the extra-membrane passages causes the hollow fiber membranes to sway, bulging outward, particularly near the second through-holes 711 (see the thick dotted lines in the figure). If the hollow fiber membranes sway and cause uneven filling, this can affect quality, such as causing variations in humidification efficiency. Therefore, as shown in the figure, the hollow fiber membrane bundle 730 is generally protected by wrapping it in mesh 750. However, in recent years, fuel cells have become increasingly large in capacity, and this has led to a demand for even higher flow rates in hollow fiber membrane modules installed in humidifiers. Therefore, simply wrapping the hollow fiber membrane bundle 730 in mesh 750 has become insufficient to suppress the oscillation of the hollow fiber membranes.

[0006] Japanese Patent Application Laid-Open No. 2020-16366

[0007] The present invention provides a hollow fiber membrane module that can suppress the oscillation of hollow fiber membranes.

[0008] The present invention employs the following means to solve the above problems.

[0009] That is, the hollow fiber membrane module of the present invention comprises: a cylindrical outer case open at both ends; a cylindrical inner case open at one end and closed at the other end, and disposed inside the outer case; a hollow fiber membrane bundle consisting of a plurality of hollow fiber membranes filled in an annular gap between the outer case and the inner case; a first sealing part at one end side of the outer case and the inner case, which seals the gaps between the plurality of hollow fiber membranes while leaving the hollow interior of each hollow fiber membrane open; and a second sealing part at the other end side of the outer case and the inner case, which seals the gaps between the plurality of hollow fiber membranes while leaving the hollow interior of each hollow fiber membrane open, and wherein a first through-hole is provided in the inner case and a second through-hole is provided in the outer case, thereby providing an extra-membrane passage that passes from the opening of the inner case through the first through-hole, outside the plurality of hollow fiber membranes, and to the second through-hole; and an intra-membrane passage that passes inside the plurality of hollow fiber membranes. and a tubular member having a plurality of third through-holes each forming a part of the extra-membrane passage is provided between the hollow fiber membrane bundle and the outer case.

[0010] According to the present invention, the tubular member can suppress the oscillation of the hollow fiber membrane. Furthermore, the tubular member is provided with a plurality of third through-holes, which provides a flow straightening effect for the fluid flowing through the extra-membrane passage.

[0011] As described above, according to the present invention, it is possible to suppress the oscillation of the hollow fiber membrane.

[0012] FIG. 1 is a front view of a hollow fiber membrane module according to Example 1 of the present invention. FIG. 2 is a plan view of the hollow fiber membrane module according to Example 1 of the present invention. FIG. 3 is a schematic cross-sectional view of the hollow fiber membrane module according to Example 1 of the present invention. FIG. 4 is a front view showing a modified example of a tubular member provided in the hollow fiber membrane module according to Example 1 of the present invention. FIG. 5 is an explanatory diagram of a tubular member according to Example 1 of the present invention. FIG. 6 is a schematic configuration diagram showing an application example of the hollow fiber membrane module according to an example of the present invention. FIG. 7 is a schematic cross-sectional view of a hollow fiber membrane module according to Example 2 of the present invention. FIG. 8 is a schematic cross-sectional view of a hollow fiber membrane module according to the prior art.

[0013] The following detailed description of the present invention will be given by way of example with reference to the accompanying drawings, although the dimensions, materials, shapes, relative positions, etc. of the components described in the examples are not intended to limit the scope of the present invention unless otherwise specified.

[0014] (Example 1) A hollow fiber membrane module according to Example 1 of the present invention will be described with reference to Figures 1 to 5. Figure 1 is a front view of the hollow fiber membrane module according to Example 1 of the present invention. Figure 2 is a plan view (top view) of the hollow fiber membrane module according to Example 1 of the present invention. Figure 3 is a schematic cross-sectional view of the hollow fiber membrane module according to Example 1 of the present invention, where Figure 3(a) is a cross-sectional view taken along line AA in Figure 2, and Figure 3(b) is a cross-sectional view taken along line BB of the outer case in Figure 2. In Figure 3(b), the positions of the inner case and the tubular member are indicated by dotted lines. Figure 4 is a front view showing a modified example of the tubular member provided in the hollow fiber membrane module according to Example 1 of the present invention. Figure 5 is an explanatory diagram of the tubular member according to Example 1 of the present invention.

[0015] <Hollow fiber membrane module> The hollow fiber membrane module 10 includes an outer case 100, an inner case 200 disposed inside the outer case 100, and a hollow fiber membrane bundle 300 consisting of a plurality of hollow fiber membranes filled in the annular gap between the outer case 100 and the inner case 200. The outer case 100 is formed of a tubular member with both ends open. The inner case 200 is formed of a tubular member with one end open (see opening 210) and the other end closed (see closing portion 220). The outer case 100 and the inner case 200 are formed of a highly rigid material (for example, a metal such as aluminum or a hard resin such as PPS).

[0016] The hollow fiber membrane module 10 also includes a first sealing portion 410 that seals the gaps between the hollow fiber membranes while leaving the hollow interiors of the hollow fiber membranes open, on one end side of the outer case 100 and the inner case 200. A protective layer 415 made of a highly flexible material such as silicone is provided inside the first sealing portion 410 to prevent damage to the hollow fiber membranes at the interface with the first sealing portion 410 even if the hollow fiber membranes vibrate.

[0017] Similarly, the hollow fiber membrane module 10 also includes a second sealing portion 420 that seals the gaps between the plurality of hollow fiber membranes while leaving the hollow interior of each hollow fiber membrane open, on the other end side of the outer case 100 and the inner case 200. A protective layer 425 is also provided on the inside of this second sealing portion 420.

[0018] Polyphenylsulfone (PPSU) is preferably used as the material for the hollow fiber membrane, and epoxy resin is preferably used as the material for the first sealing portion 410 and the second sealing portion 420. Generally, sealing portions (also called potting portions) are obtained by curing a material (potting material) such as liquid epoxy resin. By utilizing this property, the first sealing portion 410 and the second sealing portion 420 can also be fixed to the outer case 100 and the inner case 200. However, the first sealing portion 410 and the second sealing portion 420 after curing can also be fixed to the outer case 100 and the inner case 200 separately using an adhesive or the like.

[0019] The inner case 200 described above has a plurality of first through holes 230 formed around the entire circumference. These first through holes 230 are positioned toward the other end (closer to the blocking portion 220) of the inner case 200. The outer case 100 also has a second through hole 130. This second through hole 130 is positioned toward one end (the opening 210 side of the inner case 200). This configuration forms an extramembrane passage (see arrow A indicated by a solid line in FIG. 3 ) that runs from the opening (opening 210) of the inner case 200 through the first through hole 230, past the outside of the hollow fiber membranes, and to the second through hole 130. Here, the outer case 100 includes a first cylindrical portion 110 and a second cylindrical portion 120 having an inner diameter larger than that of the first cylindrical portion 110. In this embodiment, the second through-hole 130 is provided at one location in the circumferential direction of the second cylindrical portion 120. A relatively large gap is formed between the inner peripheral surface of the second cylindrical portion 120 and the outer peripheral surface of the hollow fiber membrane bundle 300 (see FIG. 3). Therefore, the fluid flowing through the extra-membrane passage reaches the second cylindrical portion 120 from the inside of the first cylindrical portion 110, flows around the entire circumference of the hollow fiber membrane bundle 300 to the outside of the bundle, and then flows into the second through-hole 130 (see FIG. 3(b)).

[0020] In the hollow fiber membrane module 10 configured as above, intra-membrane passages are also formed that pass through the interiors of the plurality of hollow fiber membranes (see arrow B indicated by a dotted line in FIG. 3(a)).

[0021] The hollow fiber membrane module 10 configured as described above can be used as a humidifier or a dehumidifier. For example, by configuring the module so that dry gas flows through the membrane passage and wet gas with a higher humidity than the dry gas flows through the membrane passage, the module can be used as a humidifier or a dehumidifier. With the above configuration, the membrane separation action of the hollow fiber membrane causes moisture in the wet gas to move into the dry gas. Therefore, the dry gas is humidified and the wet gas is dehumidified, so the module can be used as both a humidifier and a dehumidifier.

[0022] The hollow fiber membrane module 10 according to this embodiment can be suitably used as a humidifier for humidifying an electrolyte membrane included in a fuel cell. In this case, moist air generated in the fuel cell is used as the moist gas. The humidified gas (air) is then supplied to the electrolyte membrane included in the fuel cell, thereby maintaining the electrolyte membrane in a moist state.

[0023] The hollow fiber membrane module 10 includes an intra-membrane flow path that passes through the interior of the hollow fiber membranes and an extra-membrane flow path that passes outside the hollow fiber membranes. For example, the intra-membrane flow path is configured so that dry gas flows from one end of the outer case 100 through the hollow interiors of the hollow fiber membranes to the other end of the outer case 100 (see dotted arrow B in Figure 3). Furthermore, for example, the extra-membrane flow path is configured so that wet gas, which has a higher humidity than the dry gas, flows inside the outer case 100 (see solid arrow A in Figure 3).

[0024] With the above configuration, the membrane separation action of the hollow fiber membrane causes moisture in the wet gas to move into the dry gas, thus humidifying the dry gas and dehumidifying the wet gas, making the device usable as both a humidifier and a dehumidifier.

[0025] The hollow fiber membrane module 10 according to this embodiment can be suitably used as a humidifier for humidifying an electrolyte membrane included in a fuel cell 50. A configuration in which the hollow fiber membrane module 10 is used as such a humidifier will be described with reference to FIG. 6 . As shown in the figure, dry air is sent to the intra-membrane flow path of the hollow fiber membrane module 10 by a compressor 60 (see arrow R1). As described above, the dry air flowing through the intra-membrane flow path is humidified and discharged from the hollow fiber membrane module 10. This humidified wet air is sent to the fuel cell 50 (see arrow R2). This keeps the electrolyte membrane included in the fuel cell 50 moist. The wet air generated within the fuel cell 50 is then sent to the extra-membrane flow path of the hollow fiber membrane module 10 (see arrow R3), and the dry air dehumidified by the membrane separation action of the hollow fiber membrane is discharged from the hollow fiber membrane module 10 (see arrow R4). Although the temperature of the moist air generated in the fuel cell 50 is high, the temperature of the dry air sent from the compressor 60 is low, and therefore the temperature of the moist air discharged from the hollow fiber membrane module 10 is low. In this way, the hollow fiber membrane module 10 also exhibits a heat exchange function.

[0026] When the hollow fiber membrane module 10 configured as described above is used in a high-flow environment, the hollow fiber membranes tend to vibrate significantly in the second cylindrical portion 120, which has a large inner diameter, particularly near the second through-holes 130. Therefore, in this embodiment, a tubular member 500 having a plurality of third through-holes 510, each of which serves as a part of the extra-membrane passage, is provided between the hollow fiber membrane bundle 300 and the outer case 100. The plurality of third through-holes 510 are provided around the entire circumference. Like the outer case 100 and the inner case 200, the tubular member 500 is also made of a highly rigid material (e.g., a metal such as aluminum or a hard resin such as PPS). That is, the tubular member 500 is made of a highly rigid material that is not deformed or damaged by a high-flow fluid.

[0027] <Advantages of the hollow fiber membrane module according to this embodiment> According to the hollow fiber membrane module 10 according to this embodiment, the provision of the tubular member 500 makes it possible to suppress the oscillation of the hollow fiber membranes. Furthermore, the tubular member 500 is provided with a plurality of third through-holes 510, which provides a rectifying effect for the fluid flowing through the extra-membrane passage. This allows the fluid to evenly impinge on the hollow fiber membranes, thereby suppressing pressure loss. Furthermore, when used as a humidifier, humidification performance can be stabilized. To further suppress the oscillation of the hollow fiber membranes, a configuration can be adopted in which the hollow fiber membrane bundle 300 is wrapped and protected by a mesh 600, as shown in FIG. 3 .

[0028] Various embodiments of the tubular member 500 will be described below. When the tubular member 500 is manufactured from a resin material, the tubular member 500 can be obtained as a single component by a known molding technique using a mold. It is also possible to adopt a configuration in which the tubular member is divided in the circumferential direction, as in the modified tubular member 500A shown in FIG. 4 . While the illustrated example shows a tubular member divided into two, a configuration in which the tubular member is divided into three or more components can also be adopted. Adopting such a configuration has the effect of reducing the size of the mold and improving assembly ease.

[0029] The third through-holes 510 are preferably configured to suppress the vibration of the hollow fiber membranes and to effectively perform the flow straightening function. For example, the width d of the third through-holes 510 in the direction parallel to the plurality of hollow fiber membranes may be set to 1 mm or more and 8 mm or less. The flow rate of the fluid passing through the third through-holes 510 can be increased by increasing the ratio (referred to as the aperture ratio) of the total area of ​​all the third through-holes 510 to the area of ​​the outer peripheral surface of the tubular member 500 facing the extra-membrane passage (the surface facing the extra-membrane passage formed by the space between the inner peripheral surface of the second cylindrical portion 120 and the tubular member 500). However, it is desirable to design the aperture ratio taking into account the material of the tubular member 500, etc., in order to ensure the rigidity of the tubular member 500. For example, the aperture ratio may be set to 30% or more and 90% or less, preferably 30% or more and 60% or less. When the width d of the third through-holes 510 is reduced, the desired aperture ratio can be achieved by increasing the number of third through-holes 510. In Fig. 5(a), range M indicates the range of the outer peripheral surface of the cylindrical member 500 that faces the extra-membrane passage. The left side of range M in the figure is the area where the first sealing portion 410 and the protective layer 415 are provided, and the right side of range M is the area where the inner peripheral surface of the first cylindrical portion 110 comes into contact.

[0030] Furthermore, as long as the width d of the third through hole 510 is 8 mm or less, the hollow fiber membrane can be prevented from entering the hole, and therefore the planar shape of the third through hole 510 is not limited. For example, the third through hole 510 may be elliptical like the third through hole 510a shown in FIG. 5(b), oval like the third through hole 510b, rectangular like the third through hole 510c, or circular like the third through hole 510d. However, a circular planar shape of the through hole is desirable because a circular shape facilitates stress dispersion and increases the strength of the tubular member 500. Furthermore, a circular shape is desirable even when considering the flow straightening effect. On the other hand, an oval planar shape of the through hole can reduce the area of ​​the wall between adjacent through holes compared to a circular shape, making it easier to increase the aperture ratio. Furthermore, when the planar shape of the through-hole is oval, compared to when the through-hole is rectangular, the through-hole has no corners (edges), which prevents the hollow fiber membrane from being damaged by contact between the through-hole and the hollow fiber membrane, and prevents the strength of the tubular member 500 from decreasing near the through-hole. When the planar shape of the through-hole is oval, the longitudinal direction of the oval shape should be oriented in a direction intersecting (preferably perpendicular to) the direction in which the hollow fiber membrane extends (the left-right direction in FIG. 3). This prevents the hollow fiber membrane from swinging and penetrating into the third through-hole 510b. Furthermore, the opening area of ​​the third through-hole 510 can be increased while keeping the width d of the third through-hole 510 at a certain value or less.

[0031] Furthermore, it is desirable to provide a chamfer such as an R-surface or a C-surface on the inner peripheral surface of the third through-hole 510 as shown in Fig. 5(c). This more reliably prevents damage to the surface of the hollow fiber membrane. If a resin cylindrical member 500A divided in the circumferential direction as shown in Fig. 4 is used, the chamfer can be formed by molding.

[0032] (Example 2) Figure 7 shows Example 2 of the present invention. In Example 1 above, the outer case was configured from one member, but in this example, the outer case is configured from two members. Since the other basic configurations and functions are the same as in Example 1, the same components are denoted by the same reference numerals and their description will be omitted. Figure 7 is a schematic cross-sectional view of a hollow fiber membrane module according to Example 2 of the present invention.

[0033] The outer case 100 shown in the first embodiment is composed of one member (one part). That is, the first cylindrical portion 110 and the second cylindrical portion 120 are integrally formed. In contrast, the outer case 100A in this embodiment includes a first outer case 100X having the first cylindrical portion 110 and a second outer case 100Y having the second cylindrical portion 120.

[0034] Furthermore, the cylindrical member 550A in this embodiment is provided with an outward flange portion 555. When the first outer case 100X and the second outer case 100Y are fixed together, the cylindrical member 550A can be fixed by sandwiching the outward flange portion 555 between the end faces of these cases.

[0035] In the case of Example 1 described above, for example, a structure can be adopted in which the press-fitting force of the tubular member 500 into the outer case 100 is set to be high to fix the tubular member 500 to the outer case 100. In contrast, in the case of the present embodiment, the tubular member 550A can be fixed by sandwiching the outward flange portion 555 between the first outer case 100X and the second outer case 100Y, so there is no need to set the press-fitting force of the tubular member 550A high as in Example 1. Therefore, the ease of assembly of the hollow fiber membrane module can be improved.

[0036] The hollow fiber membrane module 10 according to this embodiment configured as described above can also achieve the same effects as those of the above-described Example 1. Note that the tubular member 550A according to this embodiment can also adopt a circumferentially divided configuration, similar to the tubular member 500A according to the modified example shown in Fig. 4. The third through-hole 510 is as described in Example 1 with reference to Fig. 5.

[0037] (Other) In the above examples, the outer case and the inner case are formed of cylindrical members. That is, when the case is cut in a direction perpendicular to the hollow fiber membranes, the inner and outer peripheral surfaces are circular. However, the shapes of the outer case and the inner case applicable to the present invention are not limited. That is, when the case is cut in the above direction, the inner and outer peripheral surfaces may have various shapes, such as an elliptical shape, an oval shape, or a rectangular shape. Similarly, various shapes can be used for the cylindrical members, as long as the shape of the outer peripheral surface is adapted to the shape of the inner peripheral surface of the outer case.

[0038] 10: Hollow fiber membrane module 100, 100A: Outer case 100X: First outer case 100Y: Second outer case 110: First cylindrical portion 120: Second cylindrical portion 130: Second through-hole 200: Inner case 210: Opening 220: Closure portion 230: First through-hole 300: Hollow fiber membrane bundle 410: First sealing portion 415: Protective layer 420: Second sealing portion 425: Protective layer 500, 500A, 550A: Cylindrical member 510, 510a, 510b, 510c: Third through-hole 555: Outward flange portion 600: Mesh

Claims

1. a cylindrical outer case that is open at both ends; a cylindrical inner case having one open end and the other closed end, the inner case being disposed inside the outer case; a hollow fiber membrane bundle including a plurality of hollow fiber membranes filled in an annular gap between the outer case and the inner case; a first sealing portion that seals gaps between the plurality of hollow fiber membranes at one end side of the outer case and the inner case while leaving the hollow interiors of the hollow fiber membranes open; a second sealing portion that seals gaps between the plurality of hollow fiber membranes at the other end sides of the outer case and the inner case while leaving the hollow interiors of the hollow fiber membranes open; In addition to providing a first through-hole is provided in the inner case and a second through-hole is provided in the outer case, thereby forming an extra-membrane passage that passes from the opening of the inner case through the first through-hole, passes outside the plurality of hollow fiber membranes, and reaches the second through-hole; an intramembrane passage passing through the interior of the plurality of hollow fiber membranes; A hollow fiber membrane module in which A hollow fiber membrane module characterized in that a tubular member having a plurality of third through holes each forming part of the extra-membrane passage is provided between the hollow fiber membrane bundle and the outer case.

2. A hollow fiber membrane module as described in Claim 1, wherein the third through hole is provided around the entire circumference of the tubular member.

3. The outer case has a first outer case having a first cylindrical portion and a second outer case having a second cylindrical portion, The cylindrical member is provided with an outward flange portion, The hollow fiber membrane module according to claim 1 or 2, wherein the tubular member is fixed by the outward flange portion being sandwiched between the end face of the first outer case and the end face of the second outer case.

4. The tubular member is a hollow fiber membrane module according to claim 1 or 2, which has a circumferentially divided configuration. Rule.

5. A hollow fiber membrane module as described in claim 1 or 2, wherein the width of the third through hole in a direction parallel to the plurality of hollow fiber membranes is 8 mm or less.

6. A hollow fiber membrane module as described in claim 1 or 2, wherein the planar shape of the third through hole is elliptical, oval, or rectangular.

7. A hollow fiber membrane module as described in claim 1 or 2, wherein the ratio of the total area of ​​all the third through holes to the area of ​​the surface of the outer surface of the tubular member facing the extra-membrane passage is 30% or more.

8. A hollow fiber membrane module as described in claim 1 or 2, wherein the inner surface of the third through hole is chamfered.