JP2010107126A - 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 a cylindrical case 21 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 cathode off-gas flows in from an off-gas inflow part 22a of the case 21 toward an upper face 14 of the hollow fiber membrane bundle 11. A clearance structure is provided for reducing a clearance G between the hollow fiber membrane bundle 11 and the case 21 when the cathode off-gas pushes the hollow fiber membrane bundle 11 to cause the pushed hollow fiber membrane bundle 11 and the case 21 to approach or abut on each other. <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 off gas discharged from the cathode of the battery flows through the hollow fiber membrane, respectively (see Patent Documents 1 to 3).

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

  However, in the conventional humidifier, the cathode offgas flowing into the case from the offgas inflow portion flows through the gap formed between the hollow fiber membrane bundle and the case, so that the hollow fiber membrane bundle to be originally passed through There was also a possibility that the humidification efficiency would be reduced by bypassing the inside.

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

  As means for solving the problems, the present invention includes a hollow fiber membrane bundle in which a plurality of hollow fiber membranes are bundled, and a cylindrical case that accommodates the hollow fiber membrane bundle, and includes a first fluid. Flows through the hollow fiber membrane, a second fluid having a humidity different from that of the first fluid flows inside the case and out of the hollow fiber membrane, and the second fluid flows into the second fluid from the case. A humidifier that flows into the outer peripheral surface of the hollow fiber membrane bundle from a portion, and when the second fluid pushes the hollow fiber membrane bundle, the pressed hollow fiber membrane bundle and the case approach or contact each other. A humidifier comprising a gap structure that reduces a gap between the hollow fiber membrane bundle and the case by contact.

According to such a humidifier, when the second fluid flows in from the second fluid inflow portion of the case toward the outer peripheral surface of the hollow fiber membrane bundle and pushes the hollow fiber membrane bundle, the second fluid is pushed by the gap structure. When the hollow fiber membrane bundle and the case approach or contact each other, the gap between the hollow fiber membrane bundle and the case is reduced.
Since the gap between the hollow fiber membrane bundle and the case is thus reduced, the second fluid flows into the hollow fiber membrane bundle without bypassing the hollow fiber membrane bundle, and passes through the hollow fiber membrane bundle. It becomes easy to flow. 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, in the direction of the cross section of the hollow fiber membrane, the width between the inner surfaces of the case is gradually narrowed away from the second fluid inflow portion, and the width of the hollow fiber membrane bundle is the inner surface of the case The humidifier is characterized in that it gradually decreases with increasing distance from the second fluid inflow portion, corresponding to the width between the two.

According to such a humidifier, the width between the inner surfaces of the case in the cross-sectional direction of the hollow fiber membrane is gradually narrowed away from the second fluid inflow portion in the second fluid inflow direction. Since the width of the membrane bundle gradually decreases with increasing distance from the second fluid inflow portion corresponding to the width between the inner surfaces of the case, when the second fluid pushes the hollow fiber membrane bundle, the hollow fiber membrane Of the gap between the bundle and the inner surface of the case, there are many smaller portions.
Thereby, the 2nd fluid can flow in into a hollow fiber membrane bundle suitably, without bypassing a hollow fiber membrane bundle further.

  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.

  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 coincides.

  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 and expands somewhat when it contains moisture.

  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 (see FIG. 4). 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 formed on the front side of the top wall portion 22 of the case 21 having a square cylindrical shape, that is, the upper surface 14 (one of the outer peripheral surfaces) of the hollow fiber membrane bundle 11. The hollow fiber membrane bundle 11 is pushed downward. 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.

Next, referring to FIG. 4, the structure of the hollow fiber membrane bundle 11 (hollow fiber membrane 12) in the direction of the cross section is described.
The left and right side wall portions 24, 24 of the case 21 having a rectangular tube shape project from the inner wall surfaces 24a, 24a to the center (inner side) of the case 21, have a semicircular shape in a cross-sectional view, and the length of the case 21 Projection portions 24b, 24b extending in the direction (front-rear direction) are formed.
In addition, as shown in FIG. 6, the thickness of the side wall portions 24, 24 is made constant, the constricted portions 24c, 24c are formed on the outer surfaces of the side wall portions 24, 24, and the ridge portions 24d, 24d are formed. Good.

  On the other hand, the left and right side surfaces 15, 15 of the hollow fiber membrane bundle 11 correspond to the protrusions 24 b, 24 b and have a semicircular shape in a cross-sectional view, and the axial direction of the hollow fiber membrane bundle 11 (front-rear direction) ) Extending in a semicircular groove 15a, 15a. The semicircular groove 15a is configured by appropriately bundling the hollow fiber membranes 12 so that the semicircular groove 15a is formed.

  That is, each protrusion 24 b protruding from the case 21 is in a state of being slightly fitted in each semicircular groove 15 a of the hollow fiber membrane bundle 11. Then, as will be described later, when the hollow fiber membrane bundle 11 is pushed downward by the cathode off gas, the ridge portion 24b and the semicircular groove 15a approach or contact each other, and the ridge portion 24b and the semicircular groove 15a It is comprised so that the clearance gap between may become small (refer FIG. 5).

  That is, in the first embodiment, when the cathode offgas (second fluid) pushes the hollow fiber membrane bundle 11, the hollow fiber membrane bundle 11 and the case 21 that are pushed approach or come into contact with each other. The gap structure that reduces the gap G between the bundle 11 and the case 21 includes a protruding portion 24b and a semicircular groove 15a.

≪Function and effect of humidifier≫
Next, the effect of the humidifier 1 is demonstrated with reference to FIG.
Cathode off-gas entering the case 21 from the off-gas inflow portion 22 a and flowing toward the upper surface 14 of the hollow fiber membrane bundle 11 pushes the hollow fiber membrane bundle 11 downward while flowing into the hollow fiber membrane bundle 11. Then, the hollow fiber membrane 12 bends and the hollow fiber membrane bundle 11 moves downward (see arrow A1), and the gap G between the protruding portion 24b and the semicircular groove 15a is small, or the semicircular groove 15a. Comes into contact with the protrusion 24b.

  As a result, the cathode off-gas flows into the hollow fiber membrane bundle 11 at the portion where the gap G is small (including the case of contact) (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, the humidifier which concerns on 2nd Embodiment is demonstrated with reference to FIG. 7, FIG.
As shown in FIG. 7, the side wall portions 25, 25 of the case 21 constituting the humidifier according to the second embodiment are inclined, and the inner side of the side wall portions 25, 25 in the direction of the circular cross section of the hollow fiber membrane bundle 11. The wall surfaces 25a and 25a (inner surfaces) are inclined surfaces. The width W1 between the inner wall surfaces 25a, 25a in the direction (left-right direction) orthogonal to the cathode off-gas inflow direction (up-down direction) is lower in the cathode off-gas inflow direction (up-down direction) away from the off-gas inflow portion 22a. It gradually becomes narrower as it goes.

  Further, the side surfaces 16 and 16 of the hollow fiber membrane bundle 11 according to the second embodiment are inclined corresponding to the inner wall surfaces 25a and 25a. The width W2 of the hollow fiber membrane bundle 11, more specifically, the width W2 of the hollow fiber membrane bundle 11 in the direction (left-right direction) orthogonal to the inflow direction (vertical direction) of the cathode off gas is defined between the inner wall surfaces 25a, 25a. Corresponding to the width W1, in the inflow direction (vertical direction) of the cathode offgas, it gradually decreases as it goes away from the offgas inflow portion 22a.

According to such a humidifier, as shown in FIG. 8, when the cathode off gas flowing into the case 21 pushes the hollow fiber membrane bundle 11 downward and the hollow fiber membrane bundle 11 moves downward (see arrow A3). ), The gap G formed between each side surface 16 and the entire inner wall surface 25a is reduced as a whole. That is, there are many places where the gap G becomes smaller than in the first embodiment.
That is, in the second embodiment, when the cathode off gas pushes the hollow fiber membrane bundle 11 downward, the gap structure that reduces the gap G is the inner wall surface 25a of the inclined case and the hollow that is inclined correspondingly. The side surface 16 of the thread membrane bundle 11 is provided.

  As a result, as in the first embodiment, the cathode off gas is prevented from flowing into the hollow fiber membrane bundle 11 (see arrow A4) and flowing through the hollow fiber membrane bundle 11 by bypass. Therefore, the air flowing through the hollow fiber membrane 12 can be efficiently humidified as in the first embodiment.

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.

  In the first embodiment described above, the protrusion 24b of the case 21 is slightly fitted in the semicircular groove 15a formed on the side surface 15 of the hollow fiber membrane bundle 11, and the hollow fiber membrane bundle 11 is moved downward by the cathode off gas. When pressed, the protrusion 24b and the semicircular groove 15a approach or contact each other, and the gap G is reduced (see FIGS. 4 and 5). For example, as shown in FIG. When the protruding portion 17 made of rubber is provided so as to protrude from the side surface 15 of the hollow fiber membrane bundle 11 without forming the circular groove 15a, and the hollow fiber membrane bundle 11 is pushed downward, this protruding rib It is good also as a structure which the part 17 and the protrusion part 24b of the case 21 approach or contact | abut.

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 (X1-X1 sectional view taken on the line of FIG. 2) of the humidifier which concerns on 1st Embodiment. It is a ring sectional view (X2-X2 sectional view taken on the line of FIG. 2) of the humidifier according to the first embodiment. It is a ring sectional view (X2-X2 sectional view taken on the line of FIG. 2) of the humidifier according to the first embodiment, and shows a state in which the cathode off gas pushes the hollow fiber membrane bundle downward. It is a cross-sectional view of a humidifier according to a modification. It is a cross-sectional view of the humidifier according to the second embodiment. FIG. 6 is a cross-sectional view of a humidifier according to a second embodiment, showing a state where the cathode off gas pushes the hollow fiber membrane bundle downward. It is a cross-sectional view of a humidifier according to a modification.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Humidifier 11 Hollow fiber membrane bundle 12 Hollow fiber membrane 14 Upper surface (outer peripheral surface)
15a Semicircular groove (gap structure)
17 Projection (gap structure)
21 Case 22a Off-gas inlet (second fluid inlet)
G gap

Claims (2)

A hollow fiber membrane bundle formed by bundling a plurality of hollow fiber membranes;
A cylindrical case that accommodates the hollow fiber membrane bundle,
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 out of the hollow fiber membrane;
The humidifier in which the second fluid flows from the second fluid inflow portion of the case toward the outer peripheral surface of the hollow fiber membrane bundle,
When the second fluid pushes the hollow fiber membrane bundle, a gap structure that reduces the gap between the hollow fiber membrane bundle and the case when the pushed hollow fiber membrane bundle and the case approach or contact each other. A humidifier characterized by comprising. In the circular cross-sectional direction of the hollow fiber membrane,
The width between the inner surfaces of the case is gradually narrowed away from the second fluid inflow portion,
2. The humidifier according to claim 1, wherein the width of the hollow fiber membrane bundle gradually decreases as the distance from the second fluid inflow portion increases, corresponding to the width between the inner surfaces of the case.

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