JP2010107125A - Humidifier - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a humidifier capable of performing suitable humidification regarding the humidifier for humidifying a fluid such as air supplied to a fuel cell or the like. <P>SOLUTION: The humidifier 1 includes a hollow fiber membrane bundle 11 formed by bundling a plurality of hollow fiber membranes 12 and swollen and elongated when wetted, and a cylindrical case 21 for holding the hollow fiber membrane bundle 11. Air flows through inside the hollow fiber membranes 12, and cathode off-gas with different humidity from air flows through inside the case 21 and outside the hollow fiber membranes 12. The hollow fiber membrane bundle 11 is held in the case 21 in a state of at least one part being curved, and a top wall surface 22b and a bottom wall surface 23b of the case 21 are formed so that clearances G between themselves and the hollow fiber membrane bundle 11 are reduced along the outline of the hollow fiber membrane bundle 11 when swollen and elongated. <P>COPYRIGHT: (C)2010,JPO&INPIT

Description

  The present invention relates to a humidifier that humidifies a fluid such as air supplied to a fuel cell or the like, and more particularly to a humidifier having a moisture-permeable hollow fiber membrane.

  In fuel cells such as polymer electrolyte fuel cells (PEFC), hydrogen (fuel gas) and oxygen-containing air (oxidant gas) are used to ensure the wet state of the electrolyte membrane that constitutes the fuel cell. ) Is required. Such a humidifier includes a hollow fiber membrane bundle formed by bundling hollow fiber membranes and a case that accommodates the hollow fiber membrane bundle. For example, air to be humidified toward the fuel cell passes through the inside of the hollow fiber membrane. The humid cathode offgas discharged from the cathode of the battery flows through the hollow fiber membrane, respectively (see Patent Documents 1 to 4).

JP-A-6-132038 JP-A-8-273687 Japanese Patent Laid-Open No. 10-197016 JP 2004-311287 A

  However, a hollow fiber membrane formed of a porous material such as polyimide and a bundle of hollow fiber membranes in which the hollow fiber membrane is bundled are swollen and stretched when wetted with water vapor or the like. When the hollow fiber membrane and the hollow fiber membrane bundle are expanded in this way, the hollow fiber membrane bundle (hollow fiber membrane) bends and moves in an irregular direction within the case housing the hollow fiber membrane bundle (hollow fiber membrane). Then, the gap between the hollow fiber membrane bundle and the case becomes large, and the cathode off gas that should flow through the hollow fiber membrane bundle mainly flows through the enlarged gap, which may reduce the humidification efficiency. was there.

  Then, this invention makes it a subject to provide the humidifier which can humidify suitably.

  As means for solving the above-mentioned problems, the present invention comprises a hollow fiber membrane bundle in which a plurality of hollow fiber membranes are bundled and swells and expands when wetted, and a cylindrical case that houses the hollow fiber membrane bundle. A humidifier in which a first fluid flows through the hollow fiber membrane and a second fluid having a humidity different from that of the first fluid flows in the case and flows outside the hollow fiber membrane, The hollow fiber membrane bundle is housed in the case in a state where at least one portion is curved in the longitudinal direction, and the inner surface of the case is along the outer shape of the hollow fiber membrane bundle when swollen and stretched. The humidifier is characterized in that the gap with the hollow fiber membrane bundle is small.

According to such a humidifier, when the first fluid and the second fluid flow, the hollow fiber membrane bundle wets. When wetted in this way, the hollow fiber membrane bundle swells and stretches. In this case, the hollow fiber membrane bundle is further curved at at least one curved position.
The inner surface of the case is formed in advance so as to swell and expand in this way, along the outer shape of the hollow fiber membrane bundle that is further curved in at least one place, and so that the gap with the hollow fiber membrane bundle becomes small. Therefore, the gap between the swollen and expanded hollow fiber membrane bundle and the inner surface of the case becomes small.

  Therefore, the second fluid is prevented from flowing through the gap between the hollow fiber membrane bundle and the inner surface of the case and bypassing the hollow fiber membrane bundle. That is, the second fluid flows into the hollow fiber membrane bundle and easily flows through the hollow fiber membrane bundle. Accordingly, moisture can be exchanged between the first fluid and the second fluid through the entire hollow fiber membrane bundle, that is, the entire hollow fiber membrane, and the first fluid or the second fluid having low humidity can be efficiently used. Can be humidified.

  Further, the second fluid flows from a second fluid inflow portion formed in the peripheral wall portion of the case toward the outer peripheral surface of the hollow fiber membrane bundle, and the hollow fiber membrane bundle is at the at least one location, It is a humidifier characterized by curving so that it may approach the peripheral wall part in which the said 2nd fluid inflow part was formed.

  According to such a humidifier, the hollow fiber membrane bundle that swells and expands is further curved so as to approach the peripheral wall portion where the second fluid inflow portion is formed, and the gap between the hollow fiber membrane bundle and the peripheral wall portion is increased. Get smaller. Thereby, the 2nd fluid from the 2nd fluid inflow part becomes easier to flow in into a hollow fiber membrane bundle, and it can exchange water more suitably between the 1st fluid and the 2nd fluid.

  In addition, the case is formed so that a gap between the cylindrical case body and the hollow fiber membrane bundle is reduced along the outer shape of the hollow fiber membrane bundle when the inner surface swells and expands, And an insert body attached to the inner peripheral surface of the case body.

According to such a humidifier, by attaching the insert body to the inner peripheral surface of the case main body, the inner surface formed so that the gap with the hollow fiber membrane bundle is reduced along the outer shape of the hollow fiber membrane bundle. A case can be constructed.
Moreover, even if the number of curved portions of the hollow fiber membrane bundle, the degree of curvature, and the like are different, the case can be obtained only by replacing the insert body.

  ADVANTAGE OF THE INVENTION According to this invention, the humidifier which can be humidified suitably can be provided.

<< First Embodiment >>
Hereinafter, a first embodiment of the present invention will be described with reference to FIGS.
First, a fuel cell system 100 in which the humidifier 1 according to the first embodiment is incorporated will be described with reference to FIG. The fuel cell system 100 is mounted on a fuel cell vehicle (mobile body) (not shown), and includes a fuel cell stack 110, a hydrogen tank 121, a compressor 131, and a humidifier 1.

  The fuel cell stack 110 is a polymer electrolyte fuel cell (PEFC), and a plurality of single cells formed by sandwiching MEA (Membrane Electrode Assembly) with separators (not shown) are stacked. Has been configured. The MEA includes an electrolyte membrane (solid polymer membrane) and a cathode and an anode that sandwich the membrane. Each separator is formed with an anode flow path 111 and a cathode flow path 112 formed of grooves and through holes.

  Then, hydrogen is supplied from the hydrogen tank 121 to the anode via the pipe 121a and the anode flow path 111, and oxygen-containing air is supplied from the compressor 131 that sucks outside air, and the pipe 131a, the humidifier 1, the pipe 131b, and the cathode. When supplied to the cathode via the flow path 112, an electrode reaction occurs on the catalyst (Pt or the like) contained in the anode and the cathode, and the fuel cell stack 110 is in a state capable of generating power.

  The fuel cell stack 110 in a state where power can be generated in this way and an external load (for example, a motor for traveling) are electrically connected, and when the current is taken out, the fuel cell stack 110 generates power.

Further, the anode off gas discharged from the anode channel 111 is discharged to the diluter 132 through the pipe 121b. On the other hand, the cathode offgas discharged from the cathode channel 112 is discharged to the diluter 132 via the pipe 131c, the humidifier 1, and the pipe 132a, and the diluter 132 dilutes unconsumed hydrogen in the anode offgas. It has become. The diluted gas is discharged out of the vehicle via the pipe 132b.
The cathode off gas is humid due to water vapor (water) generated by the electrode reaction at the cathode. Moreover, since a part of the generated water vapor passes through the electrolyte membrane to the anode side, the anode off-gas is also humid.

≪Configuration of humidifier≫
Next, the configuration of the humidifier 1 will be described with reference to FIGS. Here, for the sake of clarity, front, rear, left, right, upper, and lower are set with reference to FIG. Moreover, in FIGS. 3-4 and FIGS. 5-7 mentioned later, the thickness of the humidifier 1 is enlarged and described.

  The humidifier 1 humidifies the air (first fluid) to be humidified from the compressor 131 toward the cathode channel 112 with the humid cathode offgas (second fluid) discharged from the cathode channel 112. As shown in FIG. 2, the outer shape has a substantially rectangular parallelepiped shape. That is, the humidity of the cathode offgas is high, unlike the humidity of the air toward the cathode channel 112 and the humidity of the cathode offgas.

  As shown in FIG. 3, the humidifier 1 includes a hollow fiber membrane bundle 11 and a rectangular tubular case 21 that accommodates the hollow fiber membrane bundle 11. In addition, the axial direction (longitudinal direction) of the hollow fiber membrane bundle 11 and the case 21 is substantially the same.

  The hollow fiber membrane bundle 11 is made of polyimide or the like, and a plurality of hollow fiber membranes 12 having moisture permeability (for example, 10 to 10,000) are bundled. Each hollow fiber membrane 12 swells slightly when it contains moisture and expands in the axial direction. The extent to which the hollow fiber membrane 12 expands can be obtained by a preliminary test or the like in relation to the physical properties (material, water content, pore size, etc.) of the hollow fiber membrane 12 and the length thereof.

  The case 21 is a rectangular cylindrical container that accommodates the hollow fiber membrane bundle 11 therein, and is formed of a hard resin such as PC (polycarbonate) or PPO (polyphenylene oxide).

  The front side and the rear side of the hollow fiber membrane bundle 11 are fixed to the case 21 via potting portions 13 and 13 (sealing portions) formed of an epoxy resin or the like. A slight gap G is formed between the outer peripheral surface of the hollow fiber membrane bundle 11 and the inner surface of the case 21. A front cap 31 is attached to the front side of the case 21, and a rear cap 33 is attached to the rear side of the case 21.

  The air from the compressor 131 flows from the air inflow portion 34 of the rear cap 33 into the hollow fiber membranes 12 through the rear caps 33 and flows forward through the hollow fiber membranes 12. Through the inside of the front cap 31, the air flows out from the air outflow portion 32 of the front cap 31 to the outside (pipe 131b, FIG. 1).

  On the other hand, the cathode offgas flows downward from the offgas inflow portion 22a (second fluid inflow portion) formed on the front side of the top wall portion 22 (a part of the peripheral wall portion) of the case 21 having a square cylindrical shape, that is, The hollow fiber membrane bundle 11 flows toward the upper surface 14 (a part of the outer peripheral surface). The cathode off gas that has flowed in this way flows rearwardly outside the hollow fiber membrane 12 and inside the case 21, and then flows from the off gas outflow portion 23a formed on the bottom wall portion 23 of the case 21 to the outside (pipe 132a). 1).

  That is, it is configured such that the air toward the fuel cell stack 110 to be humidified flows through the hollow fiber membrane 12 forward and the humid cathode off-gas flows through the outside of the hollow fiber membrane 12 backward. . That is, the air flow direction and the cathode off-gas flow direction are opposite to each other, so that the air is efficiently humidified.

  Further, the hollow fiber membrane bundle 11 is accommodated in the case 21 in a curved state in an upward direction so as to protrude upward in a central portion A (at least one place) in the longitudinal direction (axial direction). That is, the hollow fiber membrane bundle 11 is curved so as to approach the top wall portion 22 where the offgas inflow portion 22a is formed at the central portion A between the offgas inflow portion 22a and the offgas outflow portion 23a. Thus, when the wet and swollen hollow fiber membrane bundle 11 expands, as will be described later, the hollow fiber membrane bundle 11 is configured to curve with the central portion A further protruding upward (see FIG. 4).

  In order to accommodate the hollow fiber membrane bundle 11 in the curved state in this way, for example, after the hollow fiber membrane bundle 11 is inserted into the case 21, the hollow fiber membrane bundle is used using a jig or the like. 11 is curved, and the epoxy resin or the like that becomes the potting portion 13 is cured in such a curved state.

  Further, the top wall surface 22b and the bottom wall surface 23b constituting the inner surface of the case 21 are formed along the outer shape of the hollow fiber membrane bundle 11 when swollen and stretched. That is, in the side sectional view, the top wall surface 22b is a concave curved surface in which the center portion in the front-rear direction (the axial direction of the hollow fiber membrane bundle 11) is recessed upward, and the bottom wall surface 23b is protruded upward in the center portion. It is a convex curved surface.

  In particular, the ceiling wall surface 22b is further curved by swelling and stretching, and the gap G with the upper surface 14 of the hollow fiber membrane bundle 11 in which the central portion A moves further upward is small, preferably so as to contact the upper surface 14. (See FIG. 4).

≪Function and effect of humidifier≫
Next, the effect of the humidifier 1 is demonstrated with reference to FIG.
When the humid cathode off gas flows through the case 21, the hollow fiber membrane bundle 11 (hollow fiber membrane 12) wets and swells. Then, the hollow fiber membrane bundle 11 expands and protrudes (moves) so that the curved center portion A approaches the upper ceiling wall surface 22b (see arrow A1). Thereby, the upper surface 14 and the top wall surface 22b of the hollow fiber membrane bundle 11 approach or contact each other, and the gap G (see FIG. 3) between the upper surface 14 and the top wall surface 22b is reduced, and the hollow fiber membrane bundle 11 is Furthermore, it will be in the curved state.

  In this way, when the gap G between the upper surface 14 of the hollow fiber membrane 12 and the top wall surface 22b becomes small, the cathode off-gas that does not flow into the hollow fiber membrane bundle 11 and escapes to the gap G becomes small. In that part, it flows into the hollow fiber membrane bundle 11 (see arrow A2). That is, the cathode off-gas is prevented from bypassing (detouring) the hollow fiber membrane bundle 11 that should normally flow and moving toward the off-gas outflow portion 23a without exchanging moisture with the air to be humidified. In this way, the cathode off-gas flows into the hollow fiber membrane bundle 11 and flows through the hollow fiber membrane bundle 11, so that the air flowing through the hollow fiber membrane 12 can be efficiently humidified.

<< Second Embodiment >>
Next, a humidifier according to a second embodiment will be described with reference to FIG.
The humidifier 2 according to the second embodiment includes a case 24 instead of the case 21 (see FIG. 3). The case 24 includes a case main body 25 that is a rectangular cylinder, a first insert body 26 that is attached to the top wall surface 25a (inner peripheral surface) of the case main body 25, and a bottom wall surface 25b (inner peripheral surface) of the case main body 25. And a second insert body 27 attached thereto.

  The lower surface 26a of the first insert body 26 has a concave curved surface in which the center in the front-rear direction (the axial direction of the hollow fiber membrane bundle 11) is recessed upward, similarly to the top wall surface 22b (see FIG. 3) according to the first embodiment. It has become. Moreover, the upper surface 27a of the 2nd insert body 27 is a convex curved surface which the center protruded upwards similarly to the bottom wall surface 23b (refer FIG. 3) which concerns on 1st Embodiment.

  The cathode off gas is directed from the off gas inflow portion 25 c of the case body 25 to the hollow fiber membrane bundle 11 in the case 21 through the communication hole 26 b of the first insert body 26. On the other hand, the cathode offgas after moisture exchange flows out to the outside (pipe 132a, FIG. 1) through the communication hole 27b of the second insert body 27 and the offgas outflow portion 25d of the case body 25.

According to such a humidifier 2, the hollow fiber membrane bundle is obtained by attaching the first insert body 26 and the second insert body 27 to the top wall surface 25a and the bottom wall surface 25b of the case body 25, which are square cylinders, respectively. 11, the case 24 having an inner surface formed so that the gap G with the hollow fiber membrane bundle 11 can be reduced.
Further, as in a third embodiment described later, even if the number of curved portions of the hollow fiber membrane bundle 11 and the degree of the curvature are different, it is possible to correspond to the hollow fiber membrane bundle 11 by simply replacing the insert body. Can be obtained.

<< Third Embodiment >>
Next, the humidifier which concerns on 3rd Embodiment is demonstrated with reference to FIGS.
As shown in FIG. 6, the humidifier 3 according to the third embodiment includes a hollow fiber membrane bundle 15 instead of the hollow fiber membrane bundle 11 (see FIG. 3). The hollow fiber membrane bundle 15 is curved in a substantially S shape in a side sectional view, that is, accommodated in a case 28 described later in a curved state at two locations. That is, the left side B of the hollow fiber membrane bundle 15 protrudes upward, and the right side C of the hollow fiber membrane bundle 15 protrudes downward. Therefore, when the hollow fiber membrane bundle 15 is wetted, swollen and stretched, the left side portion B protrudes (moves) further upward and the right side portion C protrudes (moves) further downward.

Moreover, the humidifier 3 according to the third embodiment includes a case 28 in which the thickness of the top wall portion 28a and the bottom wall portion 28b is constant, instead of the case 21 (see FIG. 3). The top wall surface 28c and the bottom wall surface 28d of the case 28 follow the outer shape of the hollow fiber membrane bundle 15 when swollen and stretched, and are substantially S in a side sectional view so that the gap G with the hollow fiber membrane bundle 15 becomes small. It is formed with a curved surface.
An off gas inflow portion 28e is formed on the front side of the top wall portion 28a of the case 28, and an off gas outflow portion 28f is formed on the rear side of the bottom wall portion 28b.

  According to such a humidifier 3, as shown in FIG. 7, when the hollow fiber membrane bundle 15 is wetted, swollen and stretched, the left side B of the hollow fiber membrane bundle 15 approaches the top wall 28c above it. Projecting (moving) (see arrow A3). Then, the gap G between the left side portion B of the hollow fiber membrane bundle 15 and the top wall surface 28c is further reduced, and the left side portion B is further curved upward. As a result, the cathode off-gas that has escaped into the gap G flows into the hollow fiber membrane bundle 15 at the portion where the gap G is reduced (see arrow A4).

  On the other hand, when the hollow fiber membrane bundle 15 swells and expands, the right side portion C of the hollow fiber membrane bundle 15 protrudes (moves) so as to approach the bottom wall surface 28d below (see arrow A5). Then, the gap G between the right side C of the hollow fiber membrane bundle 15 and the bottom wall surface 28d is further reduced, and the right side C is further curved downward. As a result, even if the cathode offgas flows between the left side B and the bottom wall surface 28d, the cathode offgas flows into the hollow fiber membrane bundle 15 at the portion where the gap G is reduced (arrow). (See A6). Further, the cathode off-gas flowing through the hollow fiber membrane bundle 15 is less likely to flow into the gap G and flows through the hollow fiber membrane bundle 15 as it is (see arrow A7).

  In this way, the cathode off-gas flows into the hollow fiber membrane bundle 11 and flows through the hollow fiber membrane bundle 11, so that the air flowing through the hollow fiber membrane 12 can be efficiently humidified.

As mentioned above, although one Embodiment of this invention was described, this invention is not limited to this, For example, it can change as follows in the range which does not deviate from the meaning of this invention.
In each of the above-described embodiments, the configuration in which air flows through the hollow fiber membrane 12 and the cathode off gas flows outside the hollow fiber membrane 12 is exemplified. However, the air flows outside the hollow fiber membrane 12 and has high humidity. The cathode off gas may flow through the hollow fiber membrane 12.

In addition, although the configuration in which the air and cathode off gas flow directions are opposite is illustrated, the same direction may be used.
Further, the cathode off gas flows in from the upper side of the humidifier 1 and flows out downward from the humidifier 1, but the inflow / outflow direction of the cathode off gas is not limited to this. For example, the cathode off gas flows in from the upper side. And the structure which flows out toward upper direction may be sufficient, and the structure which flows in / out from a side may be sufficient.
Furthermore, the configuration in which the first fluid is air and the second fluid is a cathode off-gas, that is, the configuration in which the first fluid and the second fluid are gases is exemplified. For example, the second fluid is water (liquid). It may be configured.

  In each of the above-described embodiments, the humidifier 1 exchanges moisture between the air and the cathode off gas, and illustrates the configuration in which the air toward the fuel cell stack 110 is humidified. Alternatively, the water may be exchanged to humidify the hydrogen toward the fuel cell stack 110.

It is a figure which shows the structure of the fuel cell system which concerns on 1st Embodiment. It is a perspective view of the humidifier concerning a 1st embodiment. It is a sectional side view of the humidifier which concerns on 1st Embodiment (X1-X1 sectional view taken on the line of FIG. 2), and shows the time of the assembly of the humidifier in which the hollow fiber membrane bundle is not swollen. It is a sectional side view of the humidifier which concerns on 1st Embodiment (X1-X1 sectional view taken on the line of FIG. 2), and shows the time of swelling when the hollow fiber membrane bundle is swollen. It is a sectional side view of the humidifier which concerns on 2nd Embodiment, and shows the time of the assembly in which the hollow fiber membrane is not swollen. It is a sectional side view of the humidifier which concerns on 3rd Embodiment, and shows the time of the assembly in which the hollow fiber membrane is not swollen. It is a sectional side view of the humidifier which concerns on 3rd Embodiment, and shows the time of swelling when the hollow fiber membrane is swollen.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Humidifier 11 Hollow fiber membrane bundle 12 Hollow fiber membrane 21 Case 22b Top wall surface (inner surface)
23b Bottom wall (inner surface)
G gap

Claims (3)

A plurality of hollow fiber membranes bundled, and a hollow fiber membrane bundle that swells and expands when wetted,
A cylindrical case that accommodates the hollow fiber membrane bundle,
A humidifier in which a first fluid flows in the hollow fiber membrane, and a second fluid having a humidity different from that of the first fluid flows in the case and flows outside the hollow fiber membrane,
The hollow fiber membrane bundle is accommodated in the case in a state where at least one portion is curved in the longitudinal direction,
The humidifier is characterized in that an inner surface of the case is formed so as to follow a contour of the hollow fiber membrane bundle when swollen and stretched, and a gap between the hollow fiber membrane bundle is reduced. The second fluid flows from the second fluid inflow portion formed in the peripheral wall portion of the case toward the outer peripheral surface of the hollow fiber membrane bundle,
2. The humidifier according to claim 1, wherein the hollow fiber membrane bundle is curved so as to approach a peripheral wall portion where the second fluid inflow portion is formed at the at least one location. The case is formed so that a gap between the cylindrical case main body and the hollow fiber membrane bundle is reduced along the outer shape of the hollow fiber membrane bundle when the inner surface swells and expands. The humidifier according to claim 1, further comprising: an insert body attached to the inner peripheral surface of the humidifier.

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