Degassing module and liquid degassing method

Abstract

The degassing module includes a plurality of degassing elements each having a plurality of hollow fiber membranes arranged around a liquid distribution pipe, a housing accommodating the plurality of degassing elements, an element connection part connected to the first degassing element and the second degassing element and forming an intermediate communication space communicating with the hollow portions of the plurality of hollow fiber membranes of the first degassing element and the hollow portions of the plurality of hollow fiber membranes of the second degassing element, and an intermediate liquid flow passage communicating with the hollow portion of the liquid distribution pipe of the first degassing element and the hollow portion of the liquid distribution pipe of the second degassing element, and a partition part dividing the area within the housing into an inner area and an outer area by the plurality of hollow fiber membranes. The housing has a liquid supply port, a liquid discharge port, and a gas port. The gas port is connected to the element connection part and communicates with the intermediate communication space.

Description

[Technical Field]

[0001] The present disclosure relates to a degassing module and a method for degassing a liquid. [Background technology]

[0002] BACKGROUND ART Conventionally, degassing modules that degas a liquid using a degassing element (hollow fiber unit) having a plurality of hollow fiber membranes have been known (see, for example, Patent Document 1). [Prior art documents] [Patent documents]

[0003] [Patent Document 1] Japanese Patent Application Laid-Open No. 2003-038904 Summary of the Invention [Problem to be solved by the invention]

[0004] In recent years, there has been a demand to reduce the concentration of carbon dioxide, a greenhouse gas, in the atmosphere in order to curb climate change. As one of the means to achieve this, methods of removing or capturing carbon dioxide from seawater are being considered. Because seawater contains a large amount of carbon dioxide, it is thought that reducing the carbon dioxide concentration in seawater can reduce the carbon dioxide concentration in the atmosphere.

[0005] Incidentally, degassing of liquids is often performed in sweep mode. Sweep mode is a method of degassing a liquid by supplying a liquid to the outside of a hollow fiber membrane and supplying a sweep gas into the hollow fiber membrane. However, in order to degas a gas from a liquid to a high concentration, it is effective to perform the degassing in vacuum mode. Vacuum mode is a method of degassing a liquid by supplying a liquid to the outside of a hollow fiber membrane and suctioning (vacuuming) the inside of the hollow fiber membrane. In vacuum mode, the pressure difference between the inside and outside of the hollow fiber membrane is larger than in sweep mode, so more gas permeates the hollow fiber membrane than in sweep mode.

[0006] In order to degas a liquid at a high flow rate, it is conceivable to use the degassing module described in Patent Document 1, in which multiple degassing elements connected to each other are housed in a single housing and used to degas the liquid. However, in this degassing module, the gas port is provided only at one end of the degassing module, so the length of the discharge path for gas that has permeated multiple hollow fiber membranes is long. Furthermore, the hollow fiber membranes are formed elongated (thin and long) to increase the membrane area (contact area with the liquid), so the pressure loss of the fluid flowing through the hollow fiber membranes is high. For this reason, there is a possibility that the discharge efficiency of gas that has permeated the hollow fiber membranes may not be sufficient.

[0007] Therefore, an object of the present disclosure is to provide a degassing module and a liquid degassing method that can increase the flow rate of the liquid to be degassed while improving the gas discharge efficiency. [Means for solving the problem]

[0008] [1] A degassing module according to the present disclosure includes a plurality of degassing elements, each having a liquid circulation pipe that has a plurality of openings formed therein and that extends in an extension direction, and a plurality of hollow fiber membranes that are arranged around the liquid circulation pipe so as to cover the plurality of openings; a housing that accommodates the plurality of degassing elements so that the plurality of degassing elements are arranged in the extension direction; an intermediate communication space that is connected to a first side degassing element and a second side degassing element that are adjacent in the extension direction among the plurality of degassing elements and that communicates with hollow portions of the plurality of hollow fiber membranes of the first side degassing element and hollow portions of the plurality of hollow fiber membranes of the second side degassing element; the housing has an element connecting part that forms an intermediate liquid flow passage that is connected to the hollow part of the element and the hollow part of the liquid flow pipe of the second-side degassing element, and a partition part that separates the area inside the housing, with the hollow fiber membranes as a boundary, into an internal area that includes the hollow parts of the plurality of hollow fiber membranes and an external area that includes the hollow part of the liquid flow pipe, and the housing has a liquid supply port for supplying liquid to the hollow part of the liquid flow pipe, a liquid discharge port for discharging liquid that has come out of the liquid flow pipe, and a gas port for discharging gas that has permeated the plurality of hollow fiber membranes, and the gas port is connected to the element connecting part and communicates with the intermediate communication space.

[0009] In this degassing module, a plurality of degassing elements are contained in a housing so that the degassing elements are arranged in the extension direction, and an element connection part connecting a first side degassing element and a second side degassing element that are adjacent to each other in the extension direction among the plurality of degassing elements forms an intermediate communication space that communicates with the hollow portions of the plurality of hollow fiber membranes of the first side degassing element and the hollow portions of the plurality of hollow fiber membranes of the second side degassing element, and an intermediate liquid flow passage that communicates with the hollow portion of the liquid flow pipe of the first side degassing element and the hollow portion of the liquid flow pipe of the second side degassing element, and a partition part separates the area within the housing, with the plurality of hollow fiber membranes as a boundary, into an internal area including the hollow portions of the plurality of hollow fiber membranes and an external area including the hollow portions of the liquid flow pipe, and the housing has a liquid supply port for supplying liquid to the hollow portion of the liquid flow pipe, a liquid discharge port for discharging liquid that has left the liquid flow pipe, and a gas port for discharging gas that has permeated the plurality of hollow fiber membranes. Therefore, liquid can be degassed in multiple degassing elements, making it possible to increase the flow rate of the liquid to be degassed. In this degassing module, the gas port is connected to the element connection section and communicates with the intermediate communication space. Therefore, compared to a case where gas ports are provided at only one end of the degassing module, the length of the discharge path for gas that has permeated multiple hollow fiber membranes can be shortened, and the imbalance between the gas discharge force acting on the first degassing element and the gas discharge force acting on the second hollow fiber membrane element can be alleviated. This increases the degassing efficiency.

[0010] [2] In the degassing module described in [1], the multiple degassing elements may include a first-end degassing element located at an end in a first extension direction, which is one direction in the extension direction, and a second-end degassing element located at an end in a second extension direction, which is the opposite direction in the extension direction, wherein the end of the hollow portion of the liquid flow pipe of the first-end degassing element facing the first extension direction is blocked, and the liquid supply port may be connected to the end of the liquid flow pipe of the second-end degassing element facing the second extension direction. In this degassing module, the end of the hollow portion of the liquid flow pipe of the first-end degassing element facing the first extension direction is blocked, and the liquid supply port is connected to the end of the liquid flow pipe of the second-end degassing element facing the second extension direction. Therefore, when liquid is supplied to the liquid supply port, the liquid is supplied to the hollow portion of the liquid flow pipe in each degassing element, exits the liquid flow pipe through the multiple openings, and comes into contact with the multiple hollow fiber membranes to be degassed. The degassed liquid then comes into contact with the hollow fiber membranes and is discharged from the liquid discharge port without returning to the hollow portion of the liquid distribution pipe. In other words, the liquid flows away from the hollow fiber membranes rather than in a direction that presses the hollow fiber membranes against the liquid distribution pipe. This prevents an increase in pressure loss as the liquid passes through the hollow fiber membranes, thereby preventing a decrease in the liquid flow rate. As a result, for example, a liquid supply device with a relatively low output can be used to supply liquid to the degassing modules.

[0011] [3] The degassing module described in [2] may further include a first-end communication space forming portion connected to the end of the first end degassing element in the first extension direction and forming a first-end communication space communicating with the hollow portions of the hollow fiber membranes of the first end degassing element, and the housing may have a first-end gas port connected to the first-end communication space forming portion and communicating with the first-end communication space. In this degassing module, the first-end communication space forming portion connected to the end of the first degassing element in the first extension direction forms a first-end communication space communicating with the hollow portions of the hollow fiber membranes of the first end degassing element, and the housing has a first-end gas port connected to the first-end communication space forming portion and communicating with the first-end communication space. This allows suction to be applied to the hollow portions of the hollow fiber membranes or a sweep gas to be supplied to the hollow portions of the hollow fiber membranes from the end of the first end degassing element in the first extension direction. This further improves degassing efficiency.

[0012] [4] In the degassing module described in [2], a second end communication space communicating with the hollow portions of the hollow fiber membranes of the second end degassing element may be formed on the second extension direction side of the second end degassing element, and the housing may have a second end gas port adjacent to the second end communication space and communicating with the second end communication space. In this degassing module, a second end communication space communicating with the hollow portions of the hollow fiber membranes of the second end degassing element may be formed on the second extension direction side of the second end degassing element, and the housing may have a second end gas port adjacent to the second end communication space and communicating with the second end communication space. This makes it possible to suction the hollow portions of the hollow fiber membranes or supply a sweep gas to the hollow portions of the hollow fiber membranes from the end of the second extension direction side of the second end degassing element. This further improves degassing efficiency.

[0013] [5] The degassing module according to [2] may further include a first-end communicating space forming part connected to the end of the first-end degassing element on the first extension direction side and forming a first-end communicating space communicating with hollow portions of the plurality of hollow fiber membranes of the first-end degassing element, a second-end communicating space formed on the second-end degassing element on the second extension direction side and communicating with hollow portions of the plurality of hollow fiber membranes of the second-end degassing element, and the housing may have a first-end gas port connected to the first-end communicating space forming part and communicating with the first-end communicating space, and a second-end gas port adjacent to the second-end communicating space and communicating with the second-end communicating space. In this degassing module, the first-end communicating space forming part connected to the end of the first degassing element on the first extension direction side forms a first-end communicating space communicating with hollow portions of the plurality of hollow fiber membranes of the first-end degassing element, and the housing has a first-end gas port connected to the first-end communicating space forming part and communicating with the first-end communicating space. Furthermore, a second end communication space is formed on the second extension direction side of the second end degassing element, and the housing has a second end gas port adjacent to the second end communication space and communicating with the second end communication space. This makes it possible to suction the hollow portions of the hollow fiber membranes or supply sweep gas to the hollow portions of the hollow fiber membranes from the end of the first end degassing element on the first extension direction side and the end of the second end degassing element on the second extension direction side, thereby further improving degassing efficiency.

[0014] [6] In the degassing module according to any one of [2] to [5], each of the plurality of degassing elements has a first fixing part located at a first element end, which is an end in a first extension direction, and fixing the plurality of hollow fiber membranes to the liquid distribution pipe so as to seal the gap between the liquid distribution pipe and the plurality of hollow fiber membranes and leave the hollow portion of the liquid distribution pipe and the hollow portions of the plurality of hollow fiber membranes open; and a second fixing part located at a second element end, which is an end in a second extension direction, and fixing the plurality of hollow fiber membranes to the liquid distribution pipe so as to seal the gap between the liquid distribution pipe and the plurality of hollow fiber membranes and leave the hollow portion of the liquid distribution pipe and the hollow portions of the plurality of hollow fiber membranes open. The element connection part has a connecting cover connected to the second fixing part of the first degassing element and the first fixing part of the second degassing element and covers the space between the first degassing element and the second degassing element, and a connecting pipe connected to the liquid distribution pipe of the first degassing element and the liquid distribution pipe of the second degassing element, and the gas port may be connected to the connecting cover. In this degassing module, the element connection part includes a connecting cover connected to the second fixing part of the first degassing element and the first fixing part of the second degassing element to cover the space between the first degassing element and the second degassing element, and a connecting pipe connected to the liquid flow pipe of the first degassing element and the liquid flow pipe of the second degassing element. Therefore, the connecting pipe forms an intermediate liquid flow passage, and the connecting cover and the connecting pipe form an intermediate communication space. Furthermore, because the gas port is connected to the connecting cover, the gas port can be connected to the intermediate communication space with a simple configuration.

[0015] [7] A liquid degassing method according to the present disclosure is a method for degassing a liquid using the degassing module described in any one of [1] to [6], comprising suctioning a gas port of the degassing module and supplying liquid to a liquid supply port of the degassing module. In this liquid degassing method, when the gas port of any of the above degassing modules is suctioned and liquid is supplied to the liquid supply port, the liquid is degassed in multiple degassing elements, thereby enabling a large flow rate of the liquid to be degassed. In this degassing module, the gas port is connected to the element connection section and communicates with the intermediate communication space. Therefore, compared to a case where a gas port is provided at only one end of the degassing module, the length of the discharge path for gas that has permeated the multiple hollow fiber membranes can be shortened, and the imbalance between the gas discharge force acting on the first degassing element and the gas discharge force acting on the second hollow fiber membrane element can be alleviated. This improves degassing efficiency.

[0016] [8] A liquid degassing method according to the present disclosure is a method for degassing a liquid using the degassing module described in [5], comprising supplying a sweep gas to at least one of the gas port, first-end gas port, and second-end gas port of the degassing module, and supplying liquid to the liquid supply port of the degassing module. In this liquid degassing method, in any of the above degassing modules, supplying a sweep gas to at least one of the gas port, first-end gas port, and second-end gas port, and supplying liquid to the liquid supply port, degassing the liquid in multiple degassing elements, thereby enabling a large flow rate of the liquid to be degassed. In this degassing module, the gas port is connected to the element connection portion and communicates with the intermediate communication space, the first-end gas port is connected to the first-end communication space forming portion and communicates with the first-end communication space, and the second-end gas port is adjacent to the second-end communication space and communicates with the second-end communication space. Therefore, compared to when gas ports are provided at only one end of the degassing module, the length of the discharge path for gas that has permeated multiple hollow fiber membranes can be shortened, and the imbalance between the gas discharge force acting on the first degassing element and the gas discharge force acting on the second hollow fiber membrane element can be alleviated, thereby improving the degassing efficiency.

[0017] [9] In the method for degassing a liquid described in [8], a sweep gas may be supplied to the gas port of the degassing module. In this method for degassing a liquid, by supplying gas to the gas port of the degassing module, the gas that has permeated the plurality of hollow fiber membranes can be discharged from the first end gas port and the second end gas port.

[0018]

[10] In the method for degassing a liquid described in [9], the first end gas port and the second end gas port of the degassing module may be suctioned. In this method for degassing a liquid, suctioning the first end gas port and the second end gas port of the degassing module can improve the efficiency of discharging gas that has permeated the multiple hollow fiber membranes.

[0019]

[11] In the liquid degassing method described in [8], a sweep gas may be supplied to the first end gas port and the second end gas port of the degassing module. In this liquid degassing method, by supplying the sweep gas to the first end gas port and the second end gas port of the module, the gas that has permeated the plurality of hollow fiber membranes can be discharged from the gas ports.

[0020]

[12] In the method for degassing a liquid according to

[11] , the gas port of the degassing module may be suctioned. In this method for degassing a liquid, suctioning the gas port of the degassing module can improve the efficiency of discharging the gas that has permeated the plurality of hollow fiber membranes. [Effects of the Invention]

[0021] According to the present disclosure, it is possible to increase the flow rate of liquid to be degassed while improving the gas discharge efficiency. [Brief explanation of the drawings]

[0022] [Figure 1] FIG. 2 is a schematic cross-sectional view of a degassing module according to an embodiment. [Figure 2] FIG. 2 is a schematic cross-sectional view of the degassing module shown in FIG. [Figure 3] FIG. 2 is a schematic front view of the degassing element. [Figure 4] FIG. 4 is a schematic cross-sectional view taken along line IV-IV shown in FIG. [Figure 5] FIG. 4 is a schematic cross-sectional view showing a part of the degassing element shown in FIG. 3. [Figure 6] FIG. 4 is a schematic cross-sectional view showing a part of the degassing element shown in FIG. 3. [Figure 7] 2 is a schematic cross-sectional view showing a part of the degassing module shown in FIG. 1. [Figure 8] 2 is a schematic cross-sectional view showing a part of the degassing module shown in FIG. 1. [Figure 9] 2 is a schematic cross-sectional view showing a part of the degassing module shown in FIG. 1. [Figure 10] FIG. 10 is a schematic cross-sectional view of another example of a degassing module. [Figure 11] FIG. 11 is a schematic cross-sectional view of the degassing module shown in FIG. [Figure 12] FIG. 10 is a schematic cross-sectional view of another example of a degassing module. [Figure 13] FIG. 10 is a schematic cross-sectional view of a degassing module for explaining another example of a method for degassing a liquid. [Figure 14] FIG. 10 is a schematic cross-sectional view of a degassing module for explaining another example of a method for degassing a liquid. DETAILED DESCRIPTION OF THE INVENTION

[0023] DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS A degassing module and a liquid degassing method according to an embodiment will be described below with reference to the accompanying drawings. In all the drawings, the same or corresponding parts are designated by the same reference numerals, and redundant description will be omitted.

[0024] [Degassing module] FIG. 1 is a schematic cross-sectional view of a degassing module according to an embodiment. FIG. 2 is a schematic cross-sectional view of the degassing module shown in FIG. 1. As shown in FIGS. 1 and 2, the degassing module 1 according to this embodiment is a module for degassing a liquid L. The liquid L is not particularly limited, but may be, for example, seawater, drinking water, pure water, ultrapure water, or other water; an aqueous solution containing ammonium sulfate, a surfactant, or the like; an organic solvent such as alcohol or hydrocarbon; or an ionic liquid. The degassing module 1 includes a plurality of degassing elements 2, a housing 3, an element connection portion 4, a baffle 5, a first-end communication space forming portion 6, and a partition portion 7. Note that only the housing 3 is shown in cross section in FIG. 1.

[0025] Fig. 3 is a schematic front view of a degassing element. Fig. 4 is a schematic cross-sectional view taken along line IV-IV in Fig. 3. Fig. 5 is a schematic cross-sectional view showing a portion of the degassing element shown in Fig. 3. Fig. 6 is a schematic cross-sectional view showing a portion of the degassing element shown in Fig. 3. As shown in Figs. 1 to 6, the degassing element 2 is for degassing a liquid L. The degassing element 2 includes a liquid distribution pipe 21, a plurality of hollow fiber membranes 22, a first fixing part 24, and a second fixing part 25.

[0026] The liquid circulation pipe 21 is a cylindrical member extending in an extension direction D. One of the two extension directions D is referred to as a first extension direction D1, and the other is referred to as a second extension direction D2. In FIG. 3, the upper side is the first extension direction D1, and the lower side is the second extension direction D2. The end of the degassing element 2 on the first extension direction D1 side is referred to as a first element end 2a, and the end of the degassing element 2 on the second extension direction D2 side is referred to as a second element end 2b.

[0027] The hollow portion 21a of the liquid circulation pipe 21 is a flow path (internal flow path) through which the liquid L can flow, and is formed by the inner circumferential surface of the liquid circulation pipe 21. The liquid circulation pipe 21 extends over the entire area in the extension direction D of the degassing element 2. That is, the liquid circulation pipe 21 extends from the end of the degassing element 2 in the first extension direction D1 to the end of the degassing element 2 in the second extension direction D2. The hollow portion 21a of the liquid circulation pipe 21 is open in the first extension direction D1 and the second extension direction D2. The opening of the hollow portion 21a of the liquid circulation pipe 21 on the first extension direction D1 side is referred to as the first end liquid circulation pipe opening 21b, and the opening of the hollow portion 21a of the liquid circulation pipe 21 on the second extension direction D2 side is referred to as the second end liquid circulation pipe opening 21c. Note that in the degassing element 2, no member such as a baffle that prevents the liquid L from moving in the extension direction D is provided in the hollow portion 21a of the liquid circulation pipe 21.

[0028] A plurality of openings 21d are formed in the liquid circulation pipe 21. The plurality of openings 21d are holes for allowing the liquid L to flow from the hollow portion 21a to the outside of the liquid circulation pipe 21, separate from the first end liquid circulation pipe opening 21b and the second end liquid circulation pipe opening 21c. In other words, the plurality of openings 21d are holes for allowing the liquid L to flow from the hollow portion 21a to the outside of the liquid circulation pipe 21 in the radial direction of the liquid circulation pipe 21. The plurality of openings 21d are formed in the peripheral wall of the liquid circulation pipe 21, and open the hollow portion 21a to the outside of the liquid circulation pipe 21.

[0029] The plurality of hollow fiber membranes 22 extend along the liquid distribution pipe 21 and are arranged around the liquid distribution pipe 21 so as to cover the plurality of openings 21d. The plurality of hollow fiber membranes 22 extending along the liquid distribution pipe 21 means that in the initial state (unused state) of the degassing element 2, the plurality of hollow fiber membranes 22 extend along the extension direction D. The plurality of hollow fiber membranes 22 form a membrane bundle that is generally cylindrical as a whole.

[0030] The plurality of hollow fiber membranes 22 are formed, for example, by a hollow fiber membrane fabric (not shown) woven in the shape of a bamboo blind. The hollow fiber membrane fabric is a fabric in which a plurality of hollow fiber membranes 22 serving as weft threads are woven with warp threads (not shown). In the hollow fiber membrane fabric, the plurality of hollow fiber membranes 22 are arranged in the shape of a bamboo blind. The hollow fiber membrane fabric is wound around the liquid distribution pipe 21 so that the plurality of hollow fiber membranes 22 extend in the extension direction D and cover the plurality of openings 21d.

[0031] The hollow portions 22a of the hollow fiber membranes 22 are flow paths (intra-membrane flow paths) through which gas G can flow, and are formed by the inner circumferential surfaces of the hollow fiber membranes 22. The plurality of hollow fiber membranes 22 extend over the entire area in the extension direction D of the degassing element 2. That is, the plurality of hollow fiber membranes 22 extend from the end of the degassing element 2 in the first extension direction D1 to the end of the degassing element 2 in the second extension direction D2. The hollow portions 22a of the plurality of hollow fiber membranes 22 are open in the first extension direction D1 and the second extension direction D2. Note that the hollow portions 22a of the plurality of hollow fiber membranes 22 refer to the hollow portions 22a of each of the plurality of hollow fiber membranes 22. The openings on the first extension direction D1 side of the hollow portions 22a of the multiple hollow fiber membranes 22 are referred to as first end hollow fiber membrane openings 22b, and the openings on the second extension direction D2 side of the hollow portions 22a of the multiple hollow fiber membranes 22 are referred to as second end hollow fiber membrane openings 22c.

[0032] The hollow fiber membrane 22 is a hollow fiber membrane that allows gas G to pass through but not liquid L to pass through. The material, shape, and form of the hollow fiber membrane 22 are not particularly limited. Examples of materials for the hollow fiber membrane 22 include polyolefin resins such as polypropylene, polyethylene, and polymethylpentene; silicone resins such as polydimethylsiloxane and its copolymers; and fluorine-based resins such as PTFE and vinylidene fluoride. Examples of the shape (sidewall shape) of the hollow fiber membrane 22 include a porous membrane, a microporous membrane, and a homogeneous membrane (non-porous membrane) that does not have any porosity. Examples of the form of the hollow fiber membrane 22 include a symmetric membrane (homogeneous membrane) in which the entire membrane has a homogeneous chemical or physical structure, and an asymmetric membrane (heterogeneous membrane) in which the chemical or physical structure of the membrane varies depending on the membrane. An asymmetric membrane (heterogeneous membrane) is a membrane that has a non-porous dense layer and a porous layer. In this case, the dense layer may be formed anywhere in the membrane, such as on the surface of the membrane or inside the porous membrane. Heterogeneous membranes also include composite membranes with different chemical structures and multilayer membranes such as three-layer structures. In particular, heterogeneous membranes using poly(4-methylpentene-1) resin are particularly preferred because they have a dense layer that blocks liquid L.

[0033] There are no particular limitations on the outer diameter of the hollow fiber membrane 22. From the viewpoint of increasing the membrane area, the outer diameter of the hollow fiber membrane 22 can be, for example, 500 μm or less, preferably 350 μm or less, and more preferably 250 μm or less. On the other hand, from the viewpoint of suppressing breakage, the outer diameter of the hollow fiber membrane 22 can be, for example, 50 μm or more, preferably 150 μm or more, and more preferably 200 μm or more.

[0034] The first fixing part 24 is located at the first element end part 2a and fixes the plurality of hollow fiber membranes 22 to the liquid distribution pipe 21 so as to seal the gap between the liquid distribution pipe 21 and the plurality of hollow fiber membranes 22 and leave the hollow portions 22a of the plurality of hollow fiber membranes 22 open. That is, the first fixing part 24 fixes the end of the plurality of hollow fiber membranes 22 on the side of the first extending direction D1 to the liquid distribution pipe 21. The first fixing part 24 seals the gap between the liquid distribution pipe 21 and the plurality of hollow fiber membranes 22. Furthermore, the first fixing part 24 is not provided in the hollow portion 21a of the liquid distribution pipe 21 or the hollow portions 22a of the plurality of hollow fiber membranes 22, so that the hollow portion 21a of the liquid distribution pipe 21 and the hollow portions 22a of the plurality of hollow fiber membranes 22 are open. The first fixing part 24 is formed of, for example, resin.

[0035] The second fixing portion 25 is located at the second element end portion 2b and fixes the plurality of hollow fiber membranes 22 to the liquid distribution pipe 21 so as to seal the gap between the liquid distribution pipe 21 and the plurality of hollow fiber membranes 22 and leave the hollow portions 22a of the plurality of hollow fiber membranes 22 open. That is, the second fixing portion 25 fixes the end of the plurality of hollow fiber membranes 22 on the side of the second extending direction D2 to the liquid distribution pipe 21. The second fixing portion 25 seals the gap between the liquid distribution pipe 21 and the plurality of hollow fiber membranes 22. Furthermore, the second fixing portion 25 is not provided in the hollow portions 21a of the liquid distribution pipe 21 and the hollow portions 22a of the plurality of hollow fiber membranes 22, so that the hollow portions 21a of the liquid distribution pipe 21 and the hollow portions 22a of the plurality of hollow fiber membranes 22 are open. The second fixing portion 25 is formed of, for example, resin.

[0036] The plurality of hollow fiber membranes 22 are not covered by a member such as a housing, and are exposed to the outside of the degassing element 2 between the first fixing part 24 and the second fixing part 25.

[0037] The housing 3 accommodates the multiple degassing elements 2 so that the multiple degassing elements 2 are arranged in the extension direction D. In this embodiment, two degassing elements 2 are accommodated in the housing 3. The two degassing elements 2 are composed of a first degassing element 2α and a second degassing element 2β. The first degassing element 2α and the second degassing element 2β are degassing elements 2 adjacent to each other in the extension direction D. The first degassing element 2α is a first-side degassing element arranged on the side in the first extension direction D1, and the second degassing element 2β is a second-side degassing element arranged on the side in the second extension direction D2. The first degassing element 2α is also a first-end degassing element located at the end of the multiple degassing elements 2 in the first extension direction D1, and the second degassing element 2β is also a second-end degassing element located at the end of the multiple degassing elements 2 in the second extension direction D2.

[0038] Fig. 7 is a schematic cross-sectional view showing a portion of the degassing module shown in Fig. 1. Fig. 8 is a schematic cross-sectional view showing a portion of the degassing module shown in Fig. 1. Fig. 9 is a schematic cross-sectional view showing a portion of the degassing module shown in Fig. 1. As shown in Figs. 1, 2, and 7 to 9, the housing 3 accommodates the first degassing element 2α and the second degassing element 2β so that a space is formed between the first degassing element 2α and the second degassing element 2β. This space is between the housing 3 and the first degassing element 2α and the second degassing element 2β, and allows the liquid L to flow therethrough.

[0039] The housing 3 includes a cylindrical portion 31 in which the first degassing element 2α and the second degassing element 2β are accommodated, a first lid portion 32 connected to one end of the cylindrical portion 31, and a second lid portion 33 connected to the end of the cylindrical portion 31 opposite the first lid portion 32. The first degassing element 2α and the second degassing element 2β are accommodated in the cylindrical portion 31 so that the extending direction D of the first degassing element 2α and the second degassing element 2β is the extending direction of the cylindrical portion 31, i.e., the opposing direction of the first lid portion 32 and the second lid portion 33. As a result, the extending direction D of the first degassing element 2α and the second degassing element 2β is the same as the extending direction of the cylindrical portion 31, and therefore the extending direction of the cylindrical portion 31 is also referred to as the extending direction D. The first lid portion 32 is connected to the end of the cylindrical portion 31 on the first extending direction D1 side so as to cover the opening of the cylindrical portion 31 on the first extending direction D1 side. The second lid portion 33 is connected to the end portion of the cylindrical portion 31 on the second extension direction D2 side so as to cover the opening of the cylindrical portion 31 on the second extension direction D2 side.

[0040] The element connecting portion 4 connects the first degassing element 2α and the second degassing element 2β. The element connecting portion 4 also disposes the first degassing element 2α and the second degassing element 2β in the extending direction D while separating them from each other.

[0041] The element connection portion 4 forms an intermediate communication space S1 and an intermediate liquid flow passage S2. The intermediate communication space S1 is a space that communicates with the hollow portions 22a of the plurality of hollow fiber membranes 22 of the first degassing element 2α and the hollow portions 22a of the plurality of hollow fiber membranes 22 of the second degassing element 2β. The intermediate communication space S1 is a space adjacent to the second end hollow fiber membrane opening 22c of the first degassing element 2α and the first end hollow fiber membrane opening 22b of the second degassing element 2β. The intermediate liquid flow passage S2 is a liquid flow passage that communicates with the hollow portions 21a of the liquid flow pipes 21 of the first degassing element 2α and the hollow portions 21a of the liquid flow pipes 21 of the second degassing element 2β. The intermediate liquid flow passage S2 is a liquid flow passage that is adjacent to the second end liquid flow pipe opening 21c of the first degassing element 2α and the first end liquid flow pipe opening 21b of the second degassing element 2β.

[0042] The element connection portion 4 has a connection cover 41 and a connection pipe 42.

[0043] The connecting cover 41 is connected to the second fixing portion 25 of the first degassing element 2α and the first fixing portion 24 of the second degassing element 2β, and is a cover that covers the space between the first degassing element 2α and the second degassing element 2β. The second fixing portion 25 of the first degassing element 2α is fitted into the connecting cover 41, thereby connecting the connecting cover 41 to the second fixing portion 25 of the first degassing element 2α. Furthermore, the first fixing portion 24 of the second degassing element 2β is fitted into the connecting cover 41, thereby connecting the connecting cover 41 to the first fixing portion 24 of the second degassing element 2β.

[0044] The connecting pipe 42 is a pipe that connects the liquid circulation pipe 21 of the first degassing element 2α and the liquid circulation pipe 21 of the second degassing element 2β. The connecting pipe 42 is connected to the liquid circulation pipe 21 of the first degassing element 2α by fitting the end of the connecting pipe 42 on the first extension direction D1 side into the end 21e of the liquid circulation pipe 21 of the first degassing element 2α on the second extension direction D2 side. Furthermore, the connecting pipe 42 is connected to the liquid circulation pipe 21 of the second degassing element 2β by fitting the end of the connecting pipe 42 on the second extension direction D2 side into the end 21f of the liquid circulation pipe 21 of the second degassing element 2β on the first extension direction D1 side.

[0045] An intermediate liquid flow passage S2 is formed by the connecting pipe 42, which connects the hollow portion 21a of the liquid flow pipe 21 of the first degassing element 2α to the hollow portion 21a of the liquid flow pipe 21 of the second degassing element 2β. An intermediate communication space S1 is formed by the connecting cover 41 and the connecting pipe 42, which connects the hollow portions 22a of the plurality of hollow fiber membranes 22 of the first degassing element 2α to the hollow portions 22a of the plurality of hollow fiber membranes 22 of the second degassing element 2β.

[0046] The baffle 5 closes the end 21f of the hollow portion 21a of the liquid flow pipe 21 of the first degassing element 2α on the first extension direction D1 side. In other words, the baffle 5 closes the hollow portion 21a at the end 21f of the liquid flow pipe 21 of the first degassing element 2α on the first extension direction D1 side. The baffle 5 is fitted into the end of the hollow portion 21a of the liquid flow pipe 21 of the first degassing element 2α on the first extension direction D1 side. The baffle 5 prevents the liquid L supplied to the hollow portions 21a of the liquid flow pipes 21 of the first degassing element 2α and the second degassing element 2β from being discharged from the first degassing element 2α in the first extension direction D1. The baffle 5 is attached only to the first degassing element 2α and does not close the hollow portion 22a of the liquid flow pipe 21 of the second degassing element 2β. Therefore, the liquid L is not discharged from the first degassing element 2α in the first extension direction D1, but is discharged radially outward from the liquid flow pipe 21 in the first degassing element 2α and the second degassing element 2β through multiple openings 21d formed in the liquid flow pipe 21.

[0047] In addition, other than the baffle 5, no member for preventing the movement of the liquid L in the extending direction D is provided in the hollow portion 21a and the intermediate liquid flow passage S2 of the liquid flow pipe 21 of the first degassing element 2α and the second degassing element 2β.

[0048] The first end communicating space forming portion 6 is connected to the first element end portion 2a, which is the end portion of the first degassing element 2α on the first extending direction D1 side, to form a first end communicating space S3. The first end communicating space S3 is a space that communicates with the hollow portions 22a of the multiple hollow fiber membranes 22 of the first degassing element 2α. The first end communicating space S3 is a space adjacent to the first extending direction D1 side of the first degassing element 2α. The first end communicating space S3 is also a space adjacent to the first end hollow fiber membrane openings 22b of the multiple hollow fiber membranes 22 of the first degassing element 2α. The first end communicating space forming portion 6 is connected to the first fixing portion 24 of the first degassing element 2α so as to cover the first element end portion 2a of the first degassing element 2α. The first end communicating space forming portion 6 forms a first end communicating space S3 between itself and the first element end portion 2a of the first degassing element 2α.

[0049] The partition 7 divides the area inside the housing 3 into an inner area R1 and an outer area R2, with the plurality of hollow fiber membranes 22 as the boundary. The inner area R1 is an area including the hollow portions 22a of the plurality of hollow fiber membranes 22. The outer area R2 is an area including the hollow portions 21a of the liquid distribution pipes 21. Therefore, the hollow fiber membranes 22 form the boundary between the inner area R1 and the outer area R2. In other words, the inside (hollow portions 22a) of the hollow fiber membranes 22 forms the inner area R1, and the outside of the hollow fiber membranes 22 forms the outer area R2. The plurality of hollow fiber membranes 22 prevent the liquid L from passing from the outer area R2 to the inner area R1, but allow the gas G (such as dissolved gas in the liquid L or air bubbles contained in the liquid L) to pass from the outer area R2 to the inner area R1. In addition, since the hollow portion 21a of the liquid flow pipe 21 is connected to the outside of the liquid flow pipe 21 by multiple openings 21d formed in the liquid flow pipe 21, the external region R2 also includes the space S4 outside the liquid flow pipe 21 that is connected to the hollow portion 21a of the liquid flow pipe 21.

[0050] The partition 7 seals the gap between the second fixing portion 25 of the second degassing element 2β and the housing 3. Therefore, a second end communication space S5 that communicates with the hollow portions 22a of the multiple hollow fiber membranes 22 of the second degassing element 2β is formed on the second extension direction D2 side of the second degassing element 2β. The second end communication space S5 is a space adjacent to the second element end portion 2b of the second degassing element 2β on the second extension direction D2 side. The second end communication space S5 is also a space adjacent to the second end hollow fiber membrane openings 22c of the second degassing element 2β. Since the second end communication space S5 communicates with the hollow portions 22a of the multiple hollow fiber membranes 22, it is also part of the internal region R1.

[0051] Moreover, the partition 7 seals the gap between the second fixing portion 25 of the second degassing element 2β and the housing 3, thereby fixing the second fixing portion 25 of the second degassing element 2β to the housing 3. The partition 7 is formed, for example, from resin.

[0052] The housing 3 has a liquid supply port 34 for supplying the liquid L to the hollow portion 21a of the liquid distribution pipe 21, a liquid discharge port 35 for discharging the liquid L coming out of the liquid distribution pipe 21, and a gas port 36, a first-end gas port 37, and a second-end gas port 38 for discharging the gas that has permeated the plurality of hollow fiber membranes 22. When the liquid L is degassed in vacuum mode, the gas port 36, the first-end gas port 37, and the second-end gas port 38 are also referred to as vacuum ports, etc. The liquid supply port 34, the liquid discharge port 35, the gas port 36, the first-end gas port 37, and the second-end gas port 38 may be configured integrally with the housing 3 or may be separate members from the housing 3.

[0053] The liquid supply port 34 is provided in the second cover portion 33 and is a port that communicates between the inside and outside of the housing 3. The liquid supply port 34 extends in a pipe shape from the second cover portion 33 to the inside of the housing 3 and is connected to the end 21e of the liquid circulation pipe 21 of the second degassing element 2β on the second extending direction D2 side. The liquid supply port 34 is also in communication with the hollow portion 21a of the liquid circulation pipe 21 of the second degassing element 2β.

[0054] The liquid discharge port 35 is provided in the first cover portion 32 and is a port that communicates between the inside and the outside of the housing 3. The liquid discharge port 35 is adjacent to the space S4 outside the liquid circulation pipe 21 and is in communication with the space S4 outside the liquid circulation pipe 21.

[0055] The gas port 36 is provided in the cylindrical portion 31 and is a port that communicates between the inside and outside of the housing 3. The gas port 36 extends in a pipe shape from the cylindrical portion 31 to the inside of the housing 3 and is connected to the connecting cover 41 of the element connection portion 4. The gas port 36 is also connected to the intermediate communication space S1.

[0056] The first-end gas port 37 is provided in the first cover portion 32 and is a port that communicates between the inside and outside of the housing 3. The first-end gas port 37 extends in a pipe shape from the first cover portion 32 to the inside of the housing 3 and is connected to the first-end communication space forming portion 6. The first-end gas port 37 is communicated with the first-end communication space S3.

[0057] The second end gas port 38 is provided in the second cover portion 33 and is a port that communicates between the inside and outside of the housing 3. The second end gas port 38 is adjacent to the second end communication space S5 and is communicated with the second end communication space S5.

[0058] [Method for degassing liquids] Next, a description will be given of a method for degassing the liquid L using the degassing module 1. Here, as an example of a method for degassing the liquid L, a method for degassing the liquid L in a vacuum mode will be described.

[0059] In this degassing method, the gas port 36, the first-end gas port 37, and the second-end gas port 38 of the degassing module 1 are suctioned, and the liquid L is supplied to the liquid supply port 34 of the degassing module 1. The suction of the gas port 36, the first-end gas port 37, and the second-end gas port 38 can be performed, for example, by connecting a suction device (not shown) such as a vacuum pump to the gas port 36, the first-end gas port 37, and the second-end gas port 38 via piping or the like and activating this suction device. The supply of the liquid L to the liquid supply port 34 can be performed, for example, by connecting a liquid supply device (not shown) such as a liquid feed pump that sends out the liquid L via piping or the like to the liquid supply port 34 and activating this liquid supply device.

[0060] When the gas port 36, the first-end gas port 37, and the second-end gas port 38 are suctioned, the internal region R1 connected to the gas port 36, the first-end gas port 37, and the second-end gas port 38 is suctioned, and the internal region R1 is decompressed. Furthermore, when the liquid L is supplied to the liquid supply port 34, the liquid L is supplied to the external region R2 connected to the liquid supply port 34. The liquid L supplied to the liquid supply port 34 is supplied to the hollow portions 21a of the liquid circulation pipes 21 of the first degassing element 2α and the second degassing element 2β. In the first degassing element 2α and the second degassing element 2β, the liquid L supplied to the hollow portions 21a of the liquid circulation pipes 21 is then discharged from the multiple openings 21d of the liquid circulation pipes 21 into the space S4 outside the liquid circulation pipes 21 and comes into contact with the multiple hollow fiber membranes 22. At this time, in the first degassing element 2α and the second degassing element 2β, the hollow portions 22a of the plurality of hollow fiber membranes 22 are in a reduced pressure state, so that gas G, such as dissolved gas in the liquid L and air bubbles contained in the liquid L, permeates the plurality of hollow fiber membranes 22. This degasses the liquid L. The degassed liquid L passes through the space between the degassing element 2 and the housing 3 and is discharged from the liquid discharge port 35. The gas G that has permeated the plurality of hollow fiber membranes 22 of the first degassing element 2α and the second degassing element 2β passes through the hollow portions 22a of the plurality of hollow fiber membranes 22 of the first degassing element 2α and the second degassing element 2β, the intermediate communicating space S1, the first end communicating space S3, and the second end communicating space S5, and is discharged from the gas port 36, the first end gas port 37, and the second end gas port 38. More specifically, the gas G that has permeated the plurality of hollow fiber membranes 22 of the first degassing element 2α passes through the hollow portions 22a of the plurality of hollow fiber membranes 22 of the first degassing element 2α, the intermediate communicating space S1, and the first end communicating space S3, and is discharged from the gas port 36 and the first end gas port 37. The gas G that has permeated the plurality of hollow fiber membranes 22 of the second degassing element 2β passes through the hollow portions 22a of the plurality of hollow fiber membranes 22 of the second degassing element 2β, the intermediate communicating space S1, and the second end communicating space S5, and is discharged from the gas port 36 and the second end gas port 38.

[0061] As described above, in the degassing module 1 according to this embodiment, the first degassing element 2α and the second degassing element 2β are accommodated in the housing 3 so that the first degassing element 2α and the second degassing element 2β are arranged in the extending direction D, and the element connecting portion 4 connected to the first degassing element 2α and the second degassing element 2β is provided with an intermediate communicating space S1 communicating with the hollow portions 22a of the plurality of hollow fiber membranes 22 of the first degassing element 2α and the hollow portions 22a of the plurality of hollow fiber membranes 22 of the second degassing element 2β, and an intermediate communicating space S2 communicating with the hollow portions 21a of the liquid distribution pipe 21 of the first degassing element 2α and the hollow portions 21a of the second degassing element The degassing module 1 includes an intermediate liquid flow passage S2 that communicates with the hollow portions 21a of the liquid flow pipes 21 of the first degassing element 2α and the second degassing element 2β. The partition 7 divides the interior of the housing 3 into an inner region R1 including the hollow portions 22a of the hollow fiber membranes 22 and an outer region R2 including the hollow portions 21a of the liquid flow pipes 21, with the hollow fiber membranes 22 as the boundary. The housing 3 has a liquid supply port 34 for supplying the liquid L to the hollow portions 21a of the liquid flow pipes 21, a liquid discharge port 35 for discharging the liquid L exiting the liquid flow pipes 21, and a gas port 36 for discharging the gas that has permeated the plurality of hollow fiber membranes 22. This allows the liquid L to be degassed in the first degassing element 2α and the second degassing element 2β, thereby enabling a large flow rate of the liquid L to be degassed. In this degassing module 1, the gas port 36 is connected to the element connection part 4 and communicates with the intermediate communication space S1. Therefore, compared to when the gas port 36 is provided at only one end of the plurality of degassing elements, the length of the discharge path for the gas G that has permeated the plurality of hollow fiber membranes 22 can be shortened, and the imbalance between the discharge force of the gas G acting on the first degassing element 2α and the discharge force of the gas G acting on the second degassing element 2β can be alleviated, thereby improving the degassing efficiency.

[0062] In this degassing module 1, the end 21f of the hollow portion 21a of the liquid circulation pipe 21 of the first degassing element 2α on the first extending direction D1 side is blocked, and a liquid supply port 34 is connected to the end 21e of the liquid circulation pipe 21 of the second degassing element 2β on the second extending direction D2 side. Therefore, when liquid L is supplied to the liquid supply port 34, the liquid L is supplied to the hollow portion 21a of the liquid circulation pipe 21 in the first degassing element 2α and the second degassing element 2β, exits the liquid circulation pipe 21 through the multiple openings 21d, and comes into contact with the multiple hollow fiber membranes 22 to be degassed. Thereafter, the liquid L that has come into contact with the multiple hollow fiber membranes 22 and been degassed is discharged from the liquid discharge port 35 without returning to the hollow portion 21a of the liquid circulation pipe 21. In other words, the liquid L does not flow in a direction that presses the multiple hollow fiber membranes 22 against the liquid circulation pipe 21, but flows in a direction that moves the multiple hollow fiber membranes 22 away from the liquid circulation pipe 21. This makes it possible to suppress an increase in pressure loss when the liquid L passes through the plurality of hollow fiber membranes 22, thereby suppressing a decrease in the flow rate of the liquid L. As a result, for example, a liquid supply device with a relatively low output can be used to supply the liquid L to the degassing module 1.

[0063] Furthermore, in this degassing module 1, the first end communicating space forming portion 6 connected to the first element end portion 2a, which is the end portion of the first degassing element 2α on the first extension direction D1 side, forms a first end communicating space S3 that communicates with the hollow portions 22a of the multiple hollow fiber membranes 22 of the first degassing element 2α, and the housing 3 has a first end gas port 37 connected to the first end communicating space forming portion 6 and communicated with the first end communicating space S3. Therefore, it is possible to suction the hollow portions 22a of the multiple hollow fiber membranes 22 or supply a sweep gas to the hollow portions 22a of the multiple hollow fiber membranes 22 from the end portion of the first degassing element 2α on the first extension direction D1 side. This further improves degassing efficiency.

[0064] Furthermore, in this degassing module 1, a second end communication space S5 that communicates with the hollow portions 22a of the multiple hollow fiber membranes 22 of the second degassing element 2β is formed on the side of the second degassing element 2β in the second extension direction D2, and the housing 3 has a second end gas port 38 that is adjacent to the second end communication space S5 and communicates with the second end communication space S5. Therefore, it is possible to suction the hollow portions 22a of the multiple hollow fiber membranes 22 or supply a sweep gas to the hollow portions 22a of the multiple hollow fiber membranes 22 from the end of the second degassing element 2β on the side of the second extension direction D2. This further improves degassing efficiency.

[0065] Furthermore, in this degassing module 1, the element connection part 4 is connected to the second fixing part 25 of the first degassing element 2α and the first fixing part 24 of the second degassing element 2β and includes a connecting cover 41 that covers the space between the first degassing element 2α and the second degassing element 2β, and a connecting pipe 42 that is connected to the liquid circulation pipe 21 of the first degassing element 2α and the liquid circulation pipe 21 of the second degassing element 2β. Therefore, an intermediate liquid circulation passage S2 is formed by the connecting pipe 42, and an intermediate communication space S1 is formed by the connecting cover 41 and the connecting pipe 42. Furthermore, because the gas port 36 is connected to the connecting cover 41, the gas port 36 can be communicated with the intermediate communication space S1 with a simple configuration.

[0066] Furthermore, in this degassing module 1, the hollow portions 21a and intermediate liquid flow passages S2 of the liquid circulation pipes 21 of the first degassing element 2α and the second degassing element 2β are not provided with any members other than the baffles 5 to prevent the liquid L from moving in the extension direction D. For this reason, the liquid L that comes out of the liquid circulation pipes 21 of the first degassing element 2α and the second degassing element 2β is discharged from the liquid discharge port 35 without returning to the first degassing element 2α and the second degassing element 2β.

[0067] Consider a comparative example of a degassing module in which a baffle or other member is provided to block either the hollow portion or the intermediate communication space of the liquid flow pipe of the first-end degassing element or the second-end degassing element so that the liquid supplied to the liquid flow pipe exits the liquid flow pipe and returns to the liquid flow pipe. In this comparative example of a degassing module, the liquid exiting the liquid flow pipe presses the hollow fiber membranes against the liquid flow pipe as it returns to the liquid flow pipe, narrowing the liquid flow path and increasing the pressure loss of the liquid. This increase in liquid pressure loss becomes more pronounced as the flow rate of the liquid increases. This reduces the flow rate of the liquid, making it necessary to use a high-output liquid supply device (not shown), such as a liquid feed pump, to deliver the liquid to the degassing module.

[0068] In contrast, in this degassing module 1, other than the baffle 5 that closes the end 21f of the hollow portion 21a of the liquid circulation pipe 21 of the first degassing element 2α on the side in the first extension direction D1, no member that blocks the movement of the liquid L in the extension direction D is provided in the hollow portion 21a of the liquid circulation pipe 21 of the first degassing element 2α and the second degassing element 2β and in the intermediate liquid circulation passage S2. Therefore, the liquid L that comes out of the liquid circulation pipe 21 is discharged from the liquid discharge port 35 without returning to the liquid circulation pipe 21. Therefore, compared to the degassing module of the comparative example, the pressure loss of the liquid is reduced and the flow rate of the liquid is improved, so that a liquid supply device with a relatively low output can be used.

[0069] In the liquid degassing method according to the present embodiment, when the gas port 36, the first-end gas port 37, and the second-end gas port 38 are suctioned and liquid L is supplied to the liquid supply port 34 in the degassing module 1, the liquid L is supplied to the hollow portion 21a of the liquid circulation pipe 21 in the first degassing element 2α and the second degassing element 2β, exits the liquid circulation pipe 21 through the multiple openings 21d, and comes into contact with the multiple hollow fiber membranes 22, thereby being degassed. In the degassing module 1, the gas port 36 is connected to the element connection portion 4 and communicates with the intermediate communication space S1. Therefore, compared to a case in which gas ports are provided at only one end of the multiple degassing modules, the length of the discharge path for gas G that has permeated the multiple hollow fiber membranes 22 can be shortened, and the imbalance between the discharge force of gas G acting on the first degassing element 2α and the discharge force of gas G acting on the second degassing element 2β can be alleviated. This improves degassing efficiency.

[0070] By degassing seawater as the liquid L, the carbon dioxide concentration in the seawater can be reduced, and thus the carbon dioxide concentration in the atmosphere can be reduced.

[0071] Although the preferred embodiments of the present disclosure have been described above, the present disclosure is not limited to the above embodiments.

[0072] For example, in the above embodiment, three gas ports for suctioning the internal region R1 were described as being provided: a gas port 36 connected to the element connection portion and communicating with the intermediate communication space, a first-end gas port 37 connected to the first-end communication space forming portion and communicating with the first-end communication space, and a second-end gas port 38 adjacent to the second-end communication space and communicating with the second-end communication space. However, as long as at least a gas port connected to the element connection portion and communicating with the intermediate communication space is provided, other gas ports may not be provided. Furthermore, in addition to the gas port connected to the element connection portion and communicating with the intermediate communication space, only one of a first-end gas port connected to the first-end communication space forming portion and communicating with the first-end communication space or a second-end gas port adjacent to the second-end communication space and communicating with the second-end communication space may be provided.

[0073] FIG. 10 is a schematic cross-sectional view of another example of a degassing module. FIG. 11 is a schematic cross-sectional view of the degassing module shown in FIG. 10. The degassing module 1A shown in FIGS. 10 and 11 has only one gas port 36 connected to the element connection portion 4 and communicating with the intermediate communication space S1 as a gas port for suctioning the internal region R1. The first cover portion 32A of the housing 3A, corresponding to the first cover portion 32 of the housing 3, does not have a first-end gas port connected to the first-end communication space forming portion and communicating with the first-end communication space. The second cover portion 33A of the housing 3A, corresponding to the second cover portion 33 of the housing 3, does not have a second-end gas port adjacent to the second-end communication space and communicating with the second-end communication space. Note that FIG. 10 shows only the housing 3A in cross section. Therefore, the first-end communication space forming portion 6A, corresponding to the first-end communication space forming portion 6, is connected only to the hollow portions 22a of the multiple hollow fiber membranes 22 of the first degassing element 2α. The second end communicating space S5 is communicated only with the hollow portions 22a of the plurality of hollow fiber membranes 22. The first end communicating space forming portion 6A may close the ends of the hollow portions 22a of the plurality of hollow fiber membranes 22 of the first degassing element 2α on the side of the first extending direction D1, without forming the first end communicating space S3. Alternatively, the ends of the hollow portions 22a of the plurality of hollow fiber membranes 22 of the second degassing element 2β on the side of the second extending direction D2 may be closed, and no second end communicating space S5 may be formed.

[0074] In this way, also in the degassing module 1A, the gas port 36 is connected to the element connection portion 4 and communicates with the intermediate communication space S1. Therefore, compared to when the gas port 36 is provided at only one end of the multiple degassing elements, the length of the discharge path for the gas G that has permeated the multiple hollow fiber membranes 22 can be shortened, and the imbalance between the discharge force of the gas G acting on the first degassing element 2α and the discharge force of the gas G acting on the second degassing element 2β can be alleviated. This makes it possible to improve the degassing efficiency.

[0075] Furthermore, in the above embodiment, the degassing module has been described as having two degassing elements, but the degassing module may also have three or more degassing elements.

[0076] 12 is a schematic cross-sectional view of another example of a degassing module. In the degassing module 1B shown in FIG. 12, four degassing elements 2 are housed in a housing 3B corresponding to the housing 3. The four degassing elements 2 are composed of a first degassing element 2α, a second degassing element 2β, a third degassing element 2γ, and a fourth degassing element 2δ. The third degassing element 2γ is a degassing element adjacent to the first degassing element 2α in the first extension direction D1. The fourth degassing element 2δ is a degassing element adjacent to the second degassing element 2β in the second extension direction D2. The first degassing element 2α, the second degassing element 2β, the third degassing element 2γ, and the fourth degassing element 2δ are housed in a cylindrical portion 31B corresponding to the cylindrical portion 31.

[0077] The third degassing element 2γ and the first degassing element 2α are degassing elements 2 adjacent to each other in the extending direction D. In relation to the third degassing element 2γ and the first degassing element 2α, the third degassing element 2γ is a first-side degassing element arranged on the first extending direction D1 side of the first degassing element 2α, and the first degassing element 2α is a second-side degassing element arranged on the second extending direction D2 side of the third degassing element 2γ.

[0078] The first degassing element 2α and the second degassing element 2β are adjacent degassing elements 2 in the extending direction D. In the relationship between the first degassing element 2α and the second degassing element 2β, the first degassing element 2α is a first-side degassing element arranged on the first extending direction D1 side of the second degassing element 2β, and the second degassing element 2β is a second-side degassing element arranged on the second extending direction D2 side of the first degassing element 2α.

[0079] The second degassing element 2β and the fourth degassing element 2δ are adjacent degassing elements 2 in the extending direction D. In the relationship between the second degassing element 2β and the fourth degassing element 2δ, the second degassing element 2β is a first-side degassing element arranged on the first extending direction D1 side of the fourth degassing element 2δ, and the fourth degassing element 2δ is a second-side degassing element arranged on the second extending direction D2 side of the second degassing element 2β.

[0080] In addition, the third degassing element 2γ is also the first end degassing element located at the end of the multiple degassing elements 2 in the first extension direction D1, and the fourth degassing element 2δ is also the second end degassing element located at the end of the multiple degassing elements 2 in the second extension direction D2.

[0081] The third degassing element 2γ and the first degassing element 2α are connected by an element connection part 4, the first degassing element 2α and the second degassing element 2β are connected by an element connection part 4, and the second degassing element 2β and the fourth degassing element 2δ are connected by an element connection part 4. The element connection part 4 connecting the first degassing element 2α and the second degassing element 2β is referred to as the first element connection part 4α. The element connection part 4 connecting the third degassing element 2γ and the first degassing element 2α is referred to as the second element connection part 4β. The element connection part 4 connecting the second degassing element 2β and the fourth degassing element 2δ is referred to as the third element connection part 4γ. The first element connection part 4α, the second element connection part 4β, and the third element connection part 4γ each form an intermediate communication space S1 and an intermediate liquid flow passage S2.

[0082] A baffle 5 (see FIG. 2) closes the end of the hollow portion 21a of the liquid flow pipe 21 of the third degassing element 2γ on the first extension direction D1 side. The baffle 5 is attached only to the third degassing element 2γ and does not close the hollow portion 22a of the liquid flow pipe 21 of the first degassing element 2α, the second degassing element 2β, and the fourth degassing element 2δ. Note that, other than the baffle 5, no member for preventing the movement of the liquid L in the extension direction D is provided in the hollow portion 21a of the liquid flow pipe 21 and each intermediate liquid flow passage S2 of the first degassing element 2α, the second degassing element 2β, the third degassing element 2γ, and the fourth degassing element 2δ.

[0083] The first end communicating space forming portion 6 is connected to the first element end portion 2a, which is the end portion of the third degassing element 2γ on the first extending direction D1 side. The first end communicating space forming portion 6 forms a first end communicating space S3, which is a space adjacent to the third degassing element 2γ on the first extending direction D1 side and adjacent to the first end hollow fiber membrane openings 22b of the plurality of hollow fiber membranes 22 of the third degassing element 2γ, and which is in communication with the hollow portions 22a of the plurality of hollow fiber membranes 22 of the third degassing element 2γ. The first end communicating space forming portion 6 is connected to the first fixing portion 24 of the third degassing element 2γ so as to cover the first element end portion 2a of the third degassing element 2γ. The first end communicating space forming portion 6 forms a first end communicating space S3 between itself and the first element end portion 2a of the third degassing element 2γ.

[0084] The partition 7 seals the gap between the second fixing portion 25 of the fourth degassing element 2δ and the housing 3B, thereby dividing the area inside the housing 3B into an inner area R1 and an outer area R2. Therefore, a second end communicating space S5 is formed on the second extension direction D2 side of the fourth degassing element 2δ, which is a space adjacent to the second element end portion 2b of the fourth degassing element 2δ on the second extension direction D2 side and adjacent to the second end hollow fiber membrane opening 22c of the fourth degassing element 2δ, and which is in communication with the hollow portions 22a of the multiple hollow fiber membranes 22 of the fourth degassing element 2δ.

[0085] The housing 3B has a liquid supply port 34, a liquid discharge port 35, three gas ports 36, a first-end gas port 37, and a second-end gas port 38. The three gas ports 36 are composed of a first gas port 36α, a second gas port 36β, and a third gas port 36γ.

[0086] The liquid supply port 34 extends in a pipe shape from the second cover portion 33 to the inside of the housing 3, and is connected to the end 21e of the liquid circulation pipe 21 of the fourth degassing element 2δ on the second extending direction D2 side. The liquid supply port 34 is in communication with the hollow portion 21a of the liquid circulation pipe 21 of the fourth degassing element 2δ.

[0087] The liquid discharge port 35 is adjacent to the space S4 outside the liquid circulation pipe 21 and is in communication with the space S4 outside the liquid circulation pipe 21.

[0088] The first gas port 36α extends in a pipe shape from the cylindrical portion 31B to the inside of the housing 3B and is connected to the first element connecting portion 4α. The first gas port 36α is connected to the intermediate communication space S1 formed by the first element connecting portion 4α.

[0089] The second gas port 36β extends in a pipe shape from the cylindrical portion 31B to the inside of the housing 3B and is connected to the second element connecting portion 4β. The second gas port 36β is connected to an intermediate communication space S1 formed by the second element connecting portion 4β.

[0090] The third gas port 36γ extends in a pipe shape from the cylindrical portion 31B to the inside of the housing 3B and is connected to the third element connecting portion 4γ. The third gas port 36γ is connected to the intermediate communication space S1 formed by the third element connecting portion 4γ.

[0091] The first-end gas port 37 extends in a pipe shape from the first cover portion 32 to the inside of the housing 3 and is connected to the first-end communicating space forming portion 6. The first-end gas port 37 is connected to the first-end communicating space S3.

[0092] The second end gas port 38 is adjacent to the second end communicating space S5 and communicates with the second end communicating space S5.

[0093] When degassing liquid L in vacuum mode using degassing module 1B, first gas port 36α, second gas port 36β, third gas port 36γ, first end gas port 37, and second end gas port 38 of degassing module 1B are suctioned, and liquid L is supplied to liquid supply port 34 of degassing module 1B. As a result, liquid L supplied to liquid supply port 34 is degassed in first degassing element 2α, second degassing element 2β, third degassing element 2γ, and fourth degassing element 2δ, and then discharged from liquid discharge port 35. Gas G that has permeated the hollow fiber membranes 22 in the first degassing element 2α, second degassing element 2β, third degassing element 2γ, and fourth degassing element 2δ passes through the hollow portions 22a of the hollow fiber membranes 22 of the first degassing element 2α, second degassing element 2β, third degassing element 2γ, and fourth degassing element 2δ, each intermediate communicating space S1, first end communicating space S3, and second end communicating space S5, and is then discharged from the first gas port 36α, second gas port 36β, third gas port 36γ, first end gas port 37, and second end gas port 38. More specifically, gas G that has permeated the hollow fiber membranes 22 of the third degassing element 2γ is discharged from the first end gas port 37 and second gas port 36β. Gas G that has permeated the hollow fiber membranes 22 of the first degassing element 2α is discharged from the second gas port 36β and first gas port 36α. The gas G that has permeated the hollow fiber membranes 22 of the second degassing element 2β is discharged from the first gas port 36α and the third gas port 36γ. The gas G that has permeated the hollow fiber membranes 22 of the fourth degassing element 2δ is discharged from the third gas port 36γ and the second end gas port 38.

[0094] In this way, also in the degassing module 1B, each gas port 36 is connected to each element connection portion 4 and communicates with the intermediate communication space S1. Therefore, compared to when gas ports 36 are provided at only one end of the multiple degassing elements, the length of the discharge path for the gas G that has permeated the multiple hollow fiber membranes 22 can be shortened, and the imbalance in the discharge forces of the gas G acting on each of the first degassing element 2α, second degassing element 2β, third degassing element 2γ, and fourth degassing element 2δ can be alleviated. This improves the degassing efficiency.

[0095] In addition, in the above embodiment, the liquid L is degassed using the vacuum mode, but the liquid L may also be degassed using the sweep mode, or the liquid L may be degassed using a combo mode that combines the sweep mode and the vacuum mode.

[0096] 13 and 14 are schematic cross-sectional views of a degassing module illustrating another example of a method for degassing a liquid. As illustrated in FIGS. 13 and 14, when degassing a liquid L in vacuum mode using the degassing module 1 of the above embodiment, a sweep gas SG is supplied to at least one of the gas port 36, the first-end gas port 37, and the second-end gas port 38 of the degassing module 1, and the liquid L is supplied to the liquid supply port 34 of the degassing module 1. The sweep gas SG may be, for example, an inert gas such as air (dry air), nitrogen gas, or argon gas. This allows for a large flow rate of the liquid L to be degassed while improving the discharge efficiency of the gas G, similar to the above embodiment. Note that FIGS. 13 and 14 show only the housing 3 in cross section.

[0097] 13, a sweep gas SG is not supplied to the first end gas port 37 and the second end gas port 38, but a sweep gas GS is supplied to the gas port 36, and liquid L is supplied to the liquid supply port 34 of the degassing module 1. The method shown in FIG. 13 can be performed in either the sweep mode or the combination mode.

[0098] 13 is performed in sweep mode, the gas port 36 serves as an air inlet port, and the first-end gas port 37 and the second-end gas port 38 serve as exhaust ports that are open to atmospheric pressure. A sweep gas GS is supplied to the gas port 36, and liquid L is supplied to the liquid supply port 34 of the degassing module 1. The supply of the sweep gas SG to the gas port 36 can be performed, for example, by connecting the gas port 36 to a gas supply device (not shown) such as a gas cylinder and a regulator via piping or the like and activating this gas supply device. The gas G that has permeated the multiple hollow fiber membranes 22 is then scavenged (swept) by the sweep gas SG supplied to the gas port 36 and discharged (opened to the atmosphere) from the first-end gas port 37 and the second-end gas port 38.

[0099] 13 is performed in the combo mode, the gas port 36 serves as an air supply port, and the first-end gas port 37 and the second-end gas port 38 serve as suction ports. A sweep gas GS is supplied to the gas port 36, the first-end gas port 37 and the second-end gas port 38 are suctioned, and the liquid L is supplied to the liquid supply port 34 of the degassing module 1. The suction of the first-end gas port 37 and the second-end gas port 38 can be performed, for example, in the same manner as in the above embodiment. The gas G that has permeated the plurality of hollow fiber membranes 22 is swept by the sweep gas SG supplied to the gas port 36, is sucked into the first-end gas port 37 and the second-end gas port 38, and is discharged from the first-end gas port 37 and the second-end gas port 38. This improves the discharge efficiency of the gas G that has permeated the plurality of hollow fiber membranes 22.

[0100] 14, a sweep gas GS is supplied to the first end gas port 37 and the second end gas port 38 without supplying a sweep gas SG to the gas port 36, and liquid L is supplied to the liquid supply port 34 of the degassing module 1. The method shown in FIG. 14 can be performed in either the sweep mode or the combination mode.

[0101] 14 is performed in sweep mode, the first-end gas port 37 and the second-end gas port 38 serve as gas supply ports, and the gas port 36 serves as an exhaust port open to atmospheric pressure. A sweep gas GS is supplied to the first-end gas port 37 and the second-end gas port 38, and liquid L is supplied to the liquid supply port 34 of the degassing module 1. The supply of the sweep gas SG to the first-end gas port 37 and the second-end gas port 38 can be achieved, for example, by connecting a gas supply device (not shown) to the first-end gas port 37 and the second-end gas port 38 via piping or the like and activating the gas supply device. The gas G that has permeated the hollow fiber membranes 22 is then swept by the sweep gas SG supplied to the first-end gas port 37 and the second-end gas port 38 and discharged (opened to the atmosphere) from the gas port 36.

[0102] 14 is performed in the combo mode, the first-end gas port 37 and the second-end gas port 38 serve as gas supply ports, and the gas port 36 serves as a suction port. A sweep gas GS is supplied to the first-end gas port 37 and the second-end gas port 38, suction is applied to the gas port 36, and liquid L is supplied to the liquid supply port 34 of the degassing module 1. Suction through the gas port 36 can be performed, for example, in the same manner as in the above embodiment. Then, gas G that has permeated the plurality of hollow fiber membranes 22 is swept by the sweep gas SG supplied to the first-end gas port 37 and the second-end gas port 38, and is then sucked into and discharged from the gas port 36. This improves the discharge efficiency of gas G that has permeated the plurality of hollow fiber membranes 22. [Explanation of symbols]

[0103] 1... degassing module, 1A... degassing module, 1B... degassing module, 2... degassing element, 2a... first element end, 2b... second element end, 2α... first degassing element, 2β... second degassing element, 2γ... third degassing element, 2δ... fourth degassing element, 3... housing, 3B... housing, 4... element connection part, 4α... first element connection part, 4β... second element connection part, 4γ... third element connection part, 5... baffle, 6... first end communication space forming part, 6A... first end communication space forming part, 7... partition part, 21... liquid circulation pipe, 21a... hollow part, 21b... first end liquid circulation pipe opening, 21c... second end liquid circulation pipe opening, 21d... opening, 21e... end, 21f... end, 22... hollow Fiber membrane, 22a...hollow portion, 22b...first end hollow fiber membrane opening, 22c...second end hollow fiber membrane opening, 24...first fixing portion, 25...second fixing portion, 31...cylindrical portion, 31B...cylindrical portion, 32...first cover portion, 33...second cover portion, 34...liquid supply port, 35...liquid discharge port, 36...gas port, 36α...first gas port, 36β...second gas port, 36γ...third gas port, 37...first end gas port, 38...second end gas port, 41...connecting cover, 42...connecting pipe, D...extension direction, D1...first extension direction, D2...second extension direction, G...gas, L...liquid, R1...inner region, R2...outer region, S1...intermediate communicating space, S2...intermediate liquid flow passage, S3...first end communicating space, S4...space, S5...second end communicating space, SG...sweep gas.

Claims

1. a plurality of degassing elements, each of which includes a liquid circulation pipe having a plurality of openings formed therein and extending in an extension direction, and a plurality of hollow fiber membranes arranged around the liquid circulation pipe so as to cover the plurality of openings; a housing that accommodates the plurality of degassing elements so that the plurality of degassing elements are arranged in the extension direction; an element connection part that is connected to a first side degassing element and a second side degassing element that are adjacent to each other in the extension direction among the plurality of degassing elements, and that forms an intermediate communication space that communicates with hollow portions of the plurality of hollow fiber membranes of the first side degassing element and hollow portions of the plurality of hollow fiber membranes of the second side degassing element, and an intermediate liquid flow passage that communicates with hollow portions of the liquid flow pipe of the first side degassing element and hollow portions of the liquid flow pipe of the second side degassing element; a partition section that partitions the area within the housing, with the hollow fiber membranes as a boundary, into an internal area including hollow portions of the hollow fiber membranes and an external area including the hollow portion of the liquid distribution pipe, The housing includes: a liquid supply port for supplying liquid to the hollow portion of the liquid circulation pipe; a liquid discharge port for discharging the liquid discharged from the liquid distribution pipe; a gas port for discharging gas that has permeated the plurality of hollow fiber membranes; the gas port is connected to the element connection portion and communicates with the intermediate communication space; Degassing module.

2. the plurality of degassing elements include a first end degassing element located at an end in a first extension direction, which is one direction in the extension direction, and a second end degassing element located at an end in a second extension direction, which is a direction opposite to the first extension direction in the extension direction, an end portion of the first end degassing element in the first extension direction of the hollow portion of the liquid circulation pipe is closed; the liquid supply port is connected to an end portion of the liquid circulation pipe of the second end degassing element on the second extension direction side; The degassing module of claim 1 .

3. a first end communicating space forming portion connected to an end portion of the first end degassing element on the first extension direction side and forming a first end communicating space that communicates with the hollow portions of the plurality of hollow fiber membranes of the first end degassing element, the housing has a first-end gas port connected to the first-end communication space forming portion and communicating with the first-end communication space; The degassing module according to claim 2 .

4. a second end communication space communicating with the hollow portions of the plurality of hollow fiber membranes of the second end degassing element is formed on the second extension direction side of the second end degassing element, the housing has a second end gas port adjacent to the second end communication space and communicating with the second end communication space; The degassing module according to claim 2 .

5. a first end communicating space forming portion connected to an end portion of the first end degassing element on the first extension direction side and forming a first end communicating space that communicates with the hollow portions of the plurality of hollow fiber membranes of the first end degassing element, a second end communication space communicating with the hollow portions of the plurality of hollow fiber membranes of the second end degassing element is formed on the second extension direction side of the second end degassing element, The housing includes: a first-end gas port connected to the first-end communication space forming portion and communicating with the first-end communication space; a second end gas port adjacent to the second end communication space and communicating with the second end communication space; The degassing module according to claim 2 .

6. Each of the plurality of degassing elements comprises: a first fixing portion located at a first element end portion that is an end portion in the first extension direction, the first fixing portion fixing the plurality of hollow fiber membranes to the liquid distribution pipe so as to seal the gap between the liquid distribution pipe and the plurality of hollow fiber membranes and leave the hollow portion of the liquid distribution pipe and the hollow portions of the hollow fiber membranes open; a second fixing portion located at a second element end portion which is an end portion in the second extension direction and which fixes the plurality of hollow fiber membranes to the liquid distribution pipe so as to seal the gap between the liquid distribution pipe and the plurality of hollow fiber membranes and leave the hollow portion of the liquid distribution pipe and the hollow portions of the plurality of hollow fiber membranes open, The element connection portion is a connecting cover connected to the second fixing portion of the first degassing element and the first fixing portion of the second degassing element, the connecting cover covering a space between the first degassing element and the second degassing element; a connecting pipe connected to the liquid circulation pipe of the first degassing element and the liquid circulation pipe of the second degassing element, The gas port is connected to the connecting cover. The degassing module according to claim 2 .

7. A method for degassing a liquid using the degassing module according to any one of claims 1 to 6, comprising: suctioning the gas port of the degassing module and supplying liquid to the liquid supply port of the degassing module; How to degas a liquid.

8. 6. A method for degassing a liquid using the degassing module of claim 5, comprising: supplying a sweep gas to at least one of the gas port, the first end gas port, and the second end gas port of the degassing module, and supplying a liquid to the liquid supply port of the degassing module; How to degas a liquid.

9. supplying a sweep gas to the gas port of the degassing module; The method for degassing a liquid according to claim 8.

10. suctioning the first end gas port and the second end gas port of the degassing module; The method for degassing a liquid according to claim 9.

11. supplying a sweep gas to the first end gas port and the second end gas port of the degassing module; The method for degassing a liquid according to claim 8.

12. suctioning the gas port of the degassing module; The method for degassing a liquid according to claim 11.

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