JP2001202976A - Humidifier - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a humidifier, which is capable of improving the amount of water recovery by making the flow turbulent, when a dry gas is fed outside a bulk hollow fiber membrane which is housed in a housing of a hollow fiber membrane module. SOLUTION: In a humidifier 2, a large number of water permeable hollow fiber membranes arranged along the longitudinal direction of a housing are housed in a housing, a moisture is exchanged between gases through feeding the gases having different moisture content inside and outside the hollow fiber membrane, respectively, and a dry gas having less moisture content is humidified. The inner wall of the housing 21a has a structure for generating turbulence.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

TECHNICAL FIELD The present invention relates to a humidifying device,
More specifically, the present invention relates to a humidifier using a water-permeable hollow fiber membrane that can suitably recover moisture from a wet gas.

[0002]

2. Description of the Related Art There is a solid polymer type fuel cell. In recent years, a fuel cell, which has attracted attention as a power source of an electric vehicle, has a problem that the moisture of an off-gas, which is a humid gas discharged from the fuel cell, is low. A humidifier that exchanges moisture with dry air is used. As a humidifier used for such a fuel cell, a humidifier that consumes less power is suitable. In addition, a small mounting space, that is, compactness is required. Therefore, although there are various types of humidifiers such as ultrasonic humidification, steam humidification, vaporization humidification, and nozzle injection, as a humidification device used for a fuel cell, a device using a hollow fiber membrane is suitably used. .

As a humidifier using a conventional hollow fiber membrane,
For example, there is one disclosed in JP-A-7-71795. The humidifier will be described with reference to FIG. 13. The humidifier 100 has a housing 101. The housing 101 has a first inlet 102 for introducing dry air and a first outlet 1 for discharging dry air.
In the housing 101, a large number of hollow fiber membrane bundles 104, for example, 5000 hollow fiber membranes, are housed. At both ends of the housing 101, fixing portions 105 and 105 'for fixing both ends of the hollow fiber membrane bundle 104 in an open state are provided. Outside the fixing portion 105, a second inlet 1 for introducing moist air is provided.
A second outlet 107 is formed outside the fixing portion 105 ′ for discharging wet air from which moisture has been separated and removed by the hollow fiber membrane bundle 104. Further, the fixing portions 105 and 105 'are covered by a second head cover 108 and a second head cover 109, respectively. The second inlet 106 is formed in the first head cover 108, and the second outlet 107
Are formed on the second head cover 109.

In the humidifying apparatus 100 using the hollow fiber membrane configured as described above, when the moist air is supplied from the second inlet 106 and passes through each hollow fiber membrane constituting the hollow fiber membrane bundle 104. The moisture in the humid air is separated by the capillary action of the hollow fiber membrane and penetrates through the capillary of the hollow fiber membrane,
Move to the outside of the hollow fiber membrane. The wet air from which the water has been separated is discharged from the second outlet 107. On the other hand, dry air is supplied from the first inlet 102. The dry air supplied from the first inlet 102 is the hollow fiber membrane bundle 1
It passes outside the hollow fiber membrane that constitutes 04. Moisture separated from the humid air moves to the outside of the hollow fiber membrane, and the humidifies the dry air. Then, the humidified dry air is discharged from the first outlet 103.

[0005]

However, in the conventional humidifier 100 using a hollow fiber membrane, the structure of the hollow fiber membrane module (for example, the hollow fiber membrane module) is established when dry air is passed outside the hollow fiber membrane bundle 104. Pressure loss due to too high a filling rate, or blockage of the flow path due to entanglement or twisting of the hollow fiber membranes, etc.). Dry air that can come into contact with the outer surface of the fiber membrane has a high concentration of moisture, but dry air that cannot contact the outer surface of the hollow fiber membrane (for example, dry air or hollow air flowing along the inner surface of the housing). In the case of dry air flowing in a place where the yarn membranes cross and contact each other, the moisture content is low, and the amount of water recovered from the wet air (humidified amount) of the dry air is reduced as a whole. .

SUMMARY OF THE INVENTION The present invention has been made to solve the above-mentioned problems, and is directed to a hollow fiber membrane bundle comprising a plurality of water-permeable hollow fiber membranes housed in a housing of a hollow fiber membrane module. It is an object of the present invention to provide a humidifier capable of improving a water recovery amount by making a turbulent flow when a dry gas flows outside.

[0007]

The gist of the invention described in claim 1 for solving the above-mentioned problem is that a large number of water-permeable hollow fiber membranes arranged along the longitudinal direction of the housing are provided. A humidifying device that is housed in the housing and exchanges moisture between the gases by flowing gases having different moisture contents to the inside and the outside of the hollow fiber membrane, and humidifies a dry gas having a small moisture content. The inner wall surface of the housing has a turbulent flow generating structure.

Thus, by providing the turbulence generating structure on the inner wall surface of the housing, the flow of the dry gas rectified along the inner wall surface and flowing in the laminar flow collides with the turbulent flow generating structure on the inner wall surface. Turbulent flow, so that the outer surface of the hollow fiber membrane bundle housed in the housing flows evenly, and the dry gas with low moisture content has a high moisture content through the water-permeable hollow fiber membrane. The amount of water recovery (humidification amount) that can be recovered from the wet gas increases.

According to another aspect of the present invention, a turbulence generating structure includes a groove formed on an inner wall surface of the housing. 4. The humidifying device according to 1.

As described above, by providing the groove on the inner wall surface of the housing, the flow of the dry gas rectified along the inner wall of the housing and flowing in the laminar flow can be disturbed by the groove to form a turbulent flow. . As a result, the dry gas uniformly flows on the outer surface of the hollow fiber membrane bundle housed in the housing, and the dry gas having a low moisture content has a high moisture content through the water-permeable hollow fiber membrane. The amount of water recovery (humidification amount) that can be recovered from the wet gas increases.

According to a third aspect of the present invention, there is provided the turbulence generating structure, wherein the turbulence generating structure has a projection on an inner wall surface of the housing. Alternatively, the humidifier according to claim 2.

As described above, by providing the projection on the inner wall surface of the housing, the flow of the dry gas can be disturbed by the projection to form a turbulent flow. As a result, the dry gas uniformly flows on the outer surface of the hollow fiber membrane bundle housed in the housing, and the dry gas having a low moisture content has a high moisture content through the water-permeable hollow fiber membrane. The amount of water recovery (humidification amount) that can be recovered from the wet gas increases.

According to another aspect of the present invention, the turbulence generating structure is characterized in that the shape of the housing is formed so as to expand axially symmetrically outward. The humidifier according to any one of claims 1 to 3.

Thus, by making the shape of the housing bulged outward in an axisymmetric manner, the flow of the dry gas in the housing can be swirled along the circumferential direction, and is accommodated in the housing. Since the drying fluid can flow from the outer side of the hollow fiber membrane bundle toward the center side, the dry gas collides with the hollow fiber membrane bundle and is disturbed to be turbulent. As a result, the dry gas uniformly flows on the outer surface of the hollow fiber membrane bundle accommodated in the housing, so that the dry gas having a low moisture content is reduced through the water-permeable hollow fiber membrane to reduce the moisture content. The amount of water recovery (humidification amount) that can be recovered from a large amount of wet gas increases.

[0015]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Hereinafter, a humidifying device 2 according to the present invention will be described.
An embodiment in which the present invention is applied to a fuel cell system will be described in detail with reference to the drawings. FIG. 1 is an overall configuration diagram of a fuel cell system to which a humidifier according to the present invention is applied.
FIG. 2 is an explanatory diagram schematically illustrating the configuration of the fuel cell of FIG. FIG. 3 is a perspective view showing the configuration of the humidifier according to the present invention. FIG. 4 is a cross-sectional view showing a gas flow in the humidifier according to the present invention.

First, the overall configuration and operation of a fuel cell system to which a humidifier according to an embodiment of the present invention is applied will be described with reference to FIG. Fuel cell system FC
S is a fuel cell 1, a humidifier 2, a gas-liquid separator 3, an air compressor 4, a combustor 5, a fuel evaporator 6, a reformer 7, a CO remover 8, and a water / methanol mixed liquid storage tank (hereinafter referred to as a tank). T) (described as “tank”). The fuel cell 1 is a solid polymer type.

In the fuel cell 1, humidified air as an oxidizing gas is supplied to the oxygen electrode side 1a, and a hydrogen-rich gas as a fuel gas is supplied to the hydrogen electrode side 1b to cause a chemical reaction between hydrogen and oxygen. Electric energy is extracted from chemical energy to generate electricity. Humidified air is generated by compressing and humidifying outside air (air) as dry gas. Here, the compression of air (dry air) is performed by the air compressor 4, and the humidification is performed by the humidifier 2 having a turbulence generating structure on the inner wall surface of the housing of the hollow fiber membrane module. Incidentally, the humidification of the dry air in the humidifier 2 is performed by exchanging moisture between the off gas discharged from the oxygen electrode side 1a of the fuel cell 1 and containing a large amount of moisture and the dry air containing a relatively small amount of moisture. This will be described in detail later.
On the other hand, fuel gas is generated by evaporating, reforming, and removing CO from a mixture of water and methanol, which are raw fuels. Here, the evaporation of the raw fuel is performed by the fuel evaporator 6, the reforming is performed by the reformer 7, and the CO removal is performed by the CO remover 8. By the way,
The raw fuel stored in the tank T is supplied to the fuel evaporator 6 via the pump P, and the raw fuel gas evaporated by the fuel evaporator 6 (a mixture of reforming air is supplied to the reformer 7). ) Is supplied, and the fuel gas reformed by the reformer 7 is supplied to the CO remover 8. In the reformer 7, steam reforming and partial oxidation of methanol are performed in the presence of a catalyst. Also,
In the CO remover 8, selective oxidation is performed in the presence of a catalyst to remove CO.
Is converted to CO ₂ . The CO remover 8 reduces the concentration of CO as much as possible. 1CO remover and No. 1 2
It is composed of two CO removers. In addition, CO remover 8
Is supplied with air for selective oxidation from the air compressor 4.

The fuel cell 1 simultaneously generates off-gas on the hydrogen electrode side 1b containing unused hydrogen and off-gas on the oxygen electrode side 1a containing a large amount of water as a reaction product. Of the humidifier 2 as described above
After being used for humidifying the air, the mixed gas is mixed with the off-gas on the hydrogen electrode side 1b, and moisture is removed by the gas-liquid separator 3. Then, the off-gas from which moisture has been removed (mixed off-gas)
The fuel is burned in the combustor 5 and used as a heat source of the fuel evaporator 6. The combustor 5 is supplied with auxiliary fuel (methanol or the like) and air to compensate for the lack of heat in the fuel evaporator 6 or to warm up the fuel cell system FCS when starting up.

Next, with reference to FIG. 2, the configuration and operation of the fuel cell which is the core of the fuel cell system FCS will be described. The configuration of the fuel cell 1 in FIG. 2 is schematically represented as one single cell (actually, the fuel cell 1 is configured as a stacked body in which about 200 single cells are stacked). As shown in FIG. 2, the fuel cell 1 is divided into a hydrogen electrode side 1b and an oxygen electrode side 1a with an electrolyte membrane 13 interposed therebetween, and each side is provided with an electrode containing a platinum-based catalyst, A hydrogen electrode 14 and an oxygen electrode 12 are formed. Then, a hydrogen-rich fuel gas generated from the raw fuel flows through the hydrogen electrode side gas passage 15, and humidified air humidified by the humidifier 2 as an oxidant gas flows through the oxygen electrode side gas passage 11. . As the electrolyte membrane 13, a solid polymer membrane, for example, a membrane using a perfluorocarbon sulfonic acid membrane as a proton exchange membrane as an electrolyte is known.
The electrolyte membrane 13 has a large number of proton exchange groups in the solid polymer, exhibits a low specific resistance of 20Ω-proton or less at room temperature by being saturated with water, and functions as a proton conductive electrolyte. Therefore, in the presence of the catalyst, protons generated by ionization of hydrogen at the hydrogen electrode 14 easily move through the electrolyte membrane 13 and reach the oxygen electrode 12. The protons that have reached the oxygen electrode 12 immediately react with oxygen ions generated from oxygen in the humidified air in the presence of a catalyst to generate water. The generated water is discharged together with the humidified air from the outlet on the oxygen electrode side 1a of the fuel cell 1 as an off-gas as a humid gas. At the hydrogen electrode 14, electrons e ⁻ are generated when hydrogen is ionized, and the generated electrons e ⁻ reach the oxygen electrode 12 via an external load M such as a motor. The humidified air thus humidified is supplied to the fuel cell 1 as an oxidizing gas when the electrolyte membrane 13 dries.
The reason for this is that the proton conductivity in the above becomes low and the power generation efficiency decreases. Therefore, in the fuel cell system FCS using the polymer electrolyte fuel cell 1, humidification has an important significance. By the way, the humidification on the fuel gas side is not necessary because the amount of water necessary for humidification of the fuel gas is added from the beginning to the raw fuel water / methanol mixture,
When the amount of water required for humidification is not added to the raw fuel, the humidifier 2 of the present invention can be applied.

Next, the configuration and operation of the humidifier 2 according to one embodiment of the present invention will be described with reference to FIGS. As shown in FIG. 3 (a), the humidifier 2 has two hollow fiber membrane modules 21 each having a substantially columnar shape in parallel, and has a box-shaped one-side distributor 22 and a other-side distributor 23.
And is configured in a rectangular parallelepiped shape as a whole. The two hollow fiber membrane modules 21 and 21 are connected to one end distributor 22.
And the other end side distributor 23 is arranged and fixed horizontally at a predetermined interval. The two hollow fiber membrane modules 21 and 21 are supplied with dry air via one end side distributor 22 and discharge off-gas from which water has been separated, and wet gas via the other end side distributor 23. The supply of the off-gas and the discharge of the humidified air can be performed.

As shown in FIG. 3B, the hollow fiber membrane module 21 includes a housing 21a and a housing 2a.
1a includes a hollow fiber membrane bundle 21b. The housing 21a has a hollow cylindrical shape with both ends opened. The housing 21a is provided with a plurality of openings (approximately eight in the circumferential direction) near both ends thereof. On the other hand, the hollow fiber membrane bundle 21b housed in the housing 21a is formed by bundling thousands of hollow fiber membranes HF having a hollow passage shown in FIG. At the end), a hollow passage for the hollow fiber membrane HF is secured and an adhesive is used to prevent the hollow fiber membrane HF from being scattered. The portion where the hollow fiber membrane bundle 21b is adhered to the housing 21a is connected to the potting portions 21g and 2g.
The potting portions 21g and 21h prevent the off-gas flowing through the hollow passage inside the hollow fiber membrane HF from mixing with the dry air (humidified air) flowing outside the hollow fiber membrane HF. I have. In the hollow fiber membrane module 21, one end face of the housing 21a is used as an off gas outlet 21d _out , and the other end face is used as an off gas inlet 21d _in . A circumferential opening at one end of the housing 21a is used as a dry air inlet 21c _in , and an opening at the other end is used as a humidified air outlet 21c _out . Incidentally, in such a hollow fiber membrane module 21, a predetermined number of bundles of hollow fiber membranes HF, HF,... It is formed by cutting and removing a bundle of hollow fiber membranes HF. The turbulence generation structure provided on the inner wall surface of the housing 21a will be described later in detail.

The one end side distributor 22 is connected to the other end as described above.
Along with the side distributor 23, two hollow fiber membrane modules 21,
21 is fixed in a predetermined positional relationship.
22 is an off gas outlet 22a and a dry air inlet 22b.
Have. Off gas outlet 22a and each hollow fiber membrane module 2
1 off-gas outlet 21d_outIs the one-side distributor 22
Connected by an internal flow path 22a 'disposed inside
(See FIGS. 4A and 4B). Similarly, the humidified air inlet 22b
Dry air inlet 21c of each hollow fiber membrane module 21
_inIs an internal flow path 22 disposed inside the one end side distributor 22.
b '(see FIGS. 4 (a) and 4 (c)).

On the other hand, the other end side distributor 23 also has an off gas inlet.
23a and a humidified air outlet 23b. Off gas inlet
23a and off-gas inlet 2 of each hollow fiber membrane module 21
1d _inIs an internal flow path 2 disposed inside the other end side distributor 23.
3a '(see FIG. 4 (a)). Similarly,
Humidification of the humidified air outlet 23b and each hollow fiber membrane module 21
Air outlet 21c_outAre arranged inside the other end distributor 23.
(See FIG. 4A).
See).

The hollow fiber membrane HF used in the hollow fiber membrane module 21 has an inner diameter of 300 as shown in FIG.
It is a thin cylindrical hollow fiber having a diameter of about micrometer to 700 micrometers. Since the hollow fiber membrane HF is thin, the membrane packing density per hollow fiber membrane module is large and the hollow fiber membrane HF can withstand high pressure. The principle of separation of water by the hollow fiber membrane HF is that the off-gas, which is a wet gas, is supplied to the hollow fiber membrane HF.
When flowing through the inside of the tube, the vapor pressure is reduced in the capillary of the hollow fiber membrane HF, so that water vapor is condensed in the capillary and becomes condensed water. This utilizes the capillary action of the hollow fiber membrane HF, in which the condensed water is sucked out by capillary action and permeates to the dry gas side flowing outside the hollow fiber membrane.

Next, referring to FIG. 3 and FIG.
The operation of will be described. The off-gas as a humid gas enters the humidifier 2 through an off-gas inlet 23a of the other end distributor 23,
The gas reaches the off-gas inlet 21d _in of the hollow fiber membrane module 21 via the internal flow path 23a '. The off gas is branched from the hollow fiber membranes HF.
It flows through the inside of HF. At this time, the off-gas gives contained moisture to dry air flowing outside the hollow fiber membrane HF. The off gas flowing inside the hollow fiber membrane HF exits the hollow fiber membrane HF from the off gas outlet 21d _out . The off-gas exiting from each of the hollow fiber membranes HF, HF,... Merges and reaches the off-gas outlet 22a through the internal flow path 22a ′,
It goes to the gas-liquid separation device 3 in the latter stage. As described above, since the internal flow path 23a 'of the other end side distributor 23 is connected to each of the two hollow fiber membrane modules 21 and 21,
The off-gas is distributed to each hollow fiber membrane module 21.
In this regard, the internal flow path 22a 'of the one end distributor 22 is the same, and therefore, the description is omitted.

On the other hand, the dry air, which is a dry gas, enters the humidifier 2 through the dry air inlet 22b of the one end side distributor 22 and passes through the internal flow path 22b 'to the hollow fiber membrane module 2.
One dry air inlet 21c _in is reached. From here, the dry air flows all over the inside of the housing 21a and flows outside the hollow fiber membrane HF. At this time, the dry air is supplied with moisture from the off gas and humidified to become humidified air. The humidified air is _supplied from the humidified air outlet 21c _out to the housing 21.
a, it reaches the humidified air outlet 23b through the internal flow path 23b ', and heads for the gas-liquid separator 3 at the subsequent stage. In addition,
As described above, the internal flow path 22b ′ of the one end side distributor 22
Is connected to each of the two hollow fiber membrane modules 21 and 21, so that the dry air is distributed to each hollow fiber membrane module 21. In this respect, the internal flow path 23b 'of the other end side distributor 23 is the same, and the description is omitted.

By packaging the hollow fiber membrane module 21 in this manner, it is possible to save space while ensuring easy handling.

Next, a turbulence generating structure provided on the inner wall surface of the housing 21a of the hollow fiber membrane module 21 of the humidifier 2 according to the present invention will be described with reference to FIGS. First, FIG. 5 shows the first embodiment of the turbulence generating structure.
This will be described with reference to FIG. As shown in FIG. 5A, the turbulent flow generation structure of the first embodiment has a lattice-shaped linear groove 31a provided on the inner wall surface of a cylindrical housing 31. The cross-sectional shape of the lattice-shaped linear groove 31a may be a semicircle or a rectangular groove. Here, the material of the housing 31 is made of resin, but may be made of metal or ceramic. Further, a dry air inflow portion 32 and a dry air outflow portion 33 for dry air, which is a dry gas, are provided at both ends of the housing 31. Since both the dry air inflow portion 32 and the dry air outflow portion 33 have the same structure, only the structure on the dry air inflow portion 32 side will be described. As shown in FIG. 5 (b), the dry air inflow section 32 has an inner circumference of the housing 31 of 8 so that the dry air introduced into the housing can forcibly generate a swirling flow in the housing 31. In the tangential direction of the divided portion, a dry air inlet 31c _in having eight circular holes having a thickness greater than the thickness of the cylinder and dry air surrounding the outside of the dry air inlet 31c _in along the circumferential direction are introduced. Ring member 32 provided with piping 32b
a. With this configuration,
When the dry air is introduced into the housing, a swirling flow is forcibly formed, so that the dry air reaches the center of the housing. On the other hand, the dry air inflow portion 22 provided on the opposite side
In the dry air outflow portion 33 having the same structure as described above, a swirling flow is formed from the center side to the outside, and the humidified air is discharged from the pipe 33b of the annular ring member 33a. In addition, a lattice-shaped linear groove 31a provided on the inner wall surface of the housing 31 allows
The flow of the dry air, which has been rectified along the inner wall surface and has flowed in a laminar flow, collides with the lattice-shaped linear grooves 31a to be disturbed and become a turbulent flow. Due to these synergistic effects, dry air having a low moisture content can efficiently collect water from the off-gas, which is a wet gas having a high moisture content, through the hollow fiber membrane, and can uniformly humidify the dry air. . As a result, the amount (rate) of water recovered from dry air can be estimated. In FIG. 5A, the off-gas flows in a countercurrent to the flow of the dry air, but may flow in a parallel flow.

Next, a second embodiment of the turbulence generating structure provided on the inner wall surface of the housing 21a will be described with reference to FIG. The turbulent flow generation structure of the second embodiment has a spiral groove 41a along the circumferential direction of the inner wall surface of the cylindrical housing 41.
Is provided. The cross-sectional shape of the spiral groove 41a may be any shape as long as it is a semicircle, a rectangle, or a groove. Housing 41
Here, a resin material is used, but a metal material or a ceramic material may be used. Also, housing 4
The dry air inflow section 4 having the same structure as the dry air inflow section 32 and the dry air outflow section 33 of the first embodiment is provided at both end portions of the first embodiment.
2 and a dry air outlet 43 are provided. In addition,
As in the first embodiment, the dry air is supplied to the dry air inlet 4
It is introduced into the housing 41 from 1c _{in and} discharged from the dry air outlet 41c _out . With this configuration, a swirling flow is forcibly formed when the dry air is introduced into the housing, so that the dry air reaches the center of the housing. In addition, due to the spiral groove provided along the circumferential direction of the inner wall surface, the flow of dry air that has been rectified along the inner wall surface and flowed in a laminar flow is disturbed and becomes turbulent,
Dry air spreads throughout the hollow fiber membrane bundle. Due to these synergistic effects, the dry air having a low moisture content can efficiently collect water from the off-gas having a high moisture content through the hollow fiber membrane, and the dry air can be uniformly humidified. As a result, the amount (rate) of water recovered from dry air can be estimated. In FIG. 6, the off-gas flows in a countercurrent to the flow of the dry air, but may flow in a parallel flow.

A third embodiment of the turbulence generating structure provided on the inner wall surface of the housing 21a will be described with reference to FIG. As shown in FIG. 7A, the turbulence generating structure according to the third embodiment is provided with a large number of straight grooves 51a along the axial direction of the inner wall surface of a cylindrical housing 51. The cross-sectional shape of the groove is rectangular in FIG. 7B, but may be a semi-circle as long as it is a groove. Here, the material of the housing 51 is made of resin, but may be made of metal or ceramic. Further, at both ends of the housing 51, a dry air inflow portion 52 and a dry air outflow portion 53 having the same structure as the dry air inflow portion 32 and the dry air outflow portion 33 of the first embodiment are provided. As in the first embodiment, the dry air is introduced into the housing 51 from the dry air inlet 51c _in and is discharged from the dry air outlet 51c _out . With this configuration, a swirling flow is forcibly formed when the dry air is introduced, so that the dry air reaches the center of the housing. In addition, the flow of the dry air that has been rectified along the inner wall surface and is flowing in a laminar flow is disturbed by a straight groove provided along the axial direction of the inner wall surface, so that the dry air is hollow. Spread all over the outer surface of the bundle. Due to these synergistic effects, dry air having a low water content can efficiently collect water from the off-gas having a high water content via the hollow fiber membrane, and can uniformly humidify the dry air. As a result, the amount (rate) of water recovered from dry air can be estimated. In FIG. 7, the off-gas flows in a countercurrent to the flow of the dry air, but may flow in a parallel flow.

A fourth embodiment of the turbulence generating structure provided on the inner wall surface of the housing 21a will be described with reference to FIG. In the turbulent flow generation structure of the fourth embodiment, a large number of annular grooves 61a are provided in the longitudinal direction of the housing 61 at appropriate intervals along the circumferential direction of the inner wall surface of the cylindrical housing 61. The cross-sectional shape of the groove may be any shape as long as it is a semicircle, a rectangle, or a groove. Here, the material of the housing 61 is made of resin, but may be made of metal or ceramic. At both ends of the housing 61, a dry air inlet 62 and a dry air outlet 63 having the same structure as the dry air inlet 32 and the dry air outlet 33 of the first embodiment are provided. Like the first embodiment, the dry air is
The air is introduced into the housing from the dry air inlet 61c _{in and} discharged from the dry air outlet 61c _out . With this configuration, a swirling flow is forcibly formed when the dry air is introduced, so that the dry air reaches the center of the housing. In addition, the flow of dry air, which has been rectified along the inner wall surface in the past, is disturbed by the annular groove colliding and disturbed by the annular groove provided along the circumferential direction of the inner wall surface, resulting in a turbulent flow. Dry air spreads over the entire outer surface of the bundle. Due to these synergistic effects, dry air having a low water content can efficiently collect water from the off-gas having a high water content via the hollow fiber membrane, and can uniformly humidify the dry air. As a result, the amount (rate) of water recovered from dry air can be estimated. In FIG. 8, the off-gas flows in a countercurrent to the flow of the dry air, but may flow in a parallel flow.

A fifth embodiment of the turbulence generating structure provided on the inner wall surface of the housing 21a will be described with reference to FIG. In the turbulent flow generating structure of the fifth embodiment, a large number of projections 71a are provided at appropriate intervals on the inner wall surface of a cylindrical housing 71. The cross-sectional shape of the projection 71a is shown in a semicircular shape in FIG. Here, the material of the housing 71 is made of resin, but may be made of metal or ceramic. Also, the housing 71
The dry air inflow portions 72 having the same structure as the dry air inflow portion 32 and the dry air outflow portion 33 of the first embodiment are provided at both ends.
And a dry air outlet 73. As in the first embodiment, the dry air is introduced into the housing from the dry air inlet 71c _in and is discharged from the dry air outlet 71c _out . With this configuration, a swirling flow is forcibly formed when the dry air is introduced, so that the dry air reaches the center of the housing. In addition, the projections provided on the inner wall surface rectify the flow of the dry air along the inner wall surface and disturb the flow of the dry air flowing in the laminar flow to become turbulent, so that the dry air flows over the entire outer surface of the hollow fiber membrane bundle. Go around. Due to these synergistic effects, dry air having a low water content can efficiently collect water from the off-gas having a high water content via the hollow fiber membrane, and can uniformly humidify the dry air. As a result, the amount (rate) of water recovered from dry air can be estimated. In FIG. 9, the off-gas flows in a countercurrent to the flow of the dry air, but may flow in a parallel flow.

Next, an embodiment of a turbulent flow generation structure in which the shape of the housing 21a is expanded axially symmetrically outward will be described with reference to FIGS. In the turbulence generating structure of the sixth embodiment, as shown in FIG. 10A, the shape of the housing 81 is not a cylinder but an elliptical shape in which a middle portion of the cylinder is swelled axially symmetrically outward. Here, the shape of the housing 81 is elliptical, but any shape such as an oval or a dish may be used as long as the central portion bulges outward in an axially symmetric manner. Although the material of the housing 81 is made of resin here, it may be made of metal or ceramic. A dry air inflow pipe 82 for introducing dry air, which is a dry gas, into the housing 81 and humidified air are provided at both ends of the housing 81.
A humidified air outflow pipe 83 is provided for exhausting from the air outlet 1. The pipe 82 and the pipe 83 are each shown in FIG.
As shown in (b), the housing 81 is provided at symmetrical positions in the tangential direction at both ends. Thus, the shape of the housing is formed into an elliptical shape bulging outward in an axially symmetric manner, and the drying air inlet pipe and the humidifying air outlet pipe are provided at symmetrical positions in the tangential direction at both ends of the housing, so that the drying introduced into the housing is achieved. The flow of the dry air, which is a gas, can be a swirling flow along the circumferential direction of the inner surface of the housing, and the dry air can flow from the outside to the center of the hollow fiber membrane bundle housed in the housing. The dry air collides with the hollow fiber membrane bundle and is disturbed to form a turbulent flow. Further, by making the shape elliptical, the packing density of the hollow fiber membrane is reduced, and the space between the hollow fiber membranes in the housing is increased, so that the contact area between the membrane and the dry air is improved. As a result, due to these synergistic effects, the dry air uniformly flows on the surface of each hollow fiber membrane housed in the housing, so that the dry air having a small moisture content is reduced through the hollow fiber membrane to the moisture content. The amount of water recovered (humidified amount) recovered from the off-gas with a large amount increases. In FIG. 10, the off-gas flows countercurrent to the flow of the dry air, but may flow in parallel.

A seventh embodiment of a turbulent flow generating structure in which the shape of the housing 21a is swelled axially outward will be described with reference to FIG. The turbulent flow generation structure of the seventh embodiment has a shape of a housing 91, such as the housing 81 of the sixth embodiment, which is not the center of the cylinder but a deformed elliptical shape in which the end of the cylinder is swelled axisymmetrically. It is. The inflated position of the housing 91 is on the side where dry air, which is dry gas, is introduced. Here the housing 9
Although the shape of No. 1 is a deformed elliptical shape, a deformed oval or dish shape may be used as long as its end is bulged outward in an axially symmetric manner. Here, the material of the housing 91 is made of resin, but may be made of metal or ceramic. At both ends of the housing 91, a dry air inflow pipe 92 for introducing dry air, which is a dry gas, into the housing 91 and a humidified air outflow pipe 93 for discharging humidified dry air from the housing 91 are provided. Is provided. Similar to the sixth embodiment, the pipes 92 and 93 are provided such that both ends of the housing 91 are symmetrical in the tangential direction. In this way, the shape of the housing is formed into an elliptical shape bulging outward in an axially symmetric manner, and the dry air inflow pipe and the humidification air outflow pipe are provided at symmetrical positions in the tangential direction at both ends of the housing, thereby being introduced into the housing. The flow of the dry air, which is a dry gas, can be a swirling flow along the circumferential direction of the inner surface of the housing, and the dry air can flow from the outside toward the center of the hollow fiber membrane bundle housed in the housing. As a result, dry air collides with the hollow fiber membrane bundle and is turbulent, resulting in turbulent flow. In addition, by forming a deformed elliptical shape, the packing density of the hollow fiber membrane is reduced, and the space between the hollow fiber membranes in the housing increases, so that the membrane comes into contact with dry air, which is a dry gas of the membrane. The area is improved. As a result, due to these synergistic effects, the dry air uniformly flows on the surface of each hollow fiber membrane housed in the housing, so that the dry air having a small moisture content is reduced through the hollow fiber membrane to the moisture content. The amount of water recovered (humidified amount) recovered from the off-gas with a large amount increases.
In FIG. 11, the off-gas flows countercurrent to the flow of the dry air, but may flow in parallel.

An eighth embodiment of a turbulent flow generating structure in which the shape of the housing 21a is swelled outward in an axially symmetric manner will be described with reference to FIG. In the turbulent flow generation structure according to the eighth embodiment, the shape of the housing 91 'is not a cylinder but an elliptical shape in which the end of the cylinder is expanded symmetrically with respect to the axis. The position where the housing 91 'is inflated is the side where the dry air, which is the dry gas, is discharged. Here, the shape of the housing 91 'is a deformed ellipse, but any shape may be used as long as the end is axially symmetrical and bulges outward, whether it is a deformed oval or a dish. At both ends of the housing 91, a dry air inflow pipe 92 ′ for introducing dry air, which is a dry gas, into the housing 91 and a humidified air outflow pipe 93 for discharging humidified dry air from the housing 91. 'Is provided. The pipes 92 ′ and 93 ′ are provided at symmetrical positions in the tangential direction at both ends of the housing 91, similarly to the seventh embodiment. In this way, the shape of the housing is formed into an elliptical shape bulging outward in an axially symmetric manner, and the dry air inflow pipe and the humidification air outflow pipe are provided at symmetrical positions in the tangential direction at both ends of the housing, thereby being introduced into the housing. The flow of the dry air, which is a dry gas, can be a swirling flow along the circumferential direction of the inner surface of the housing, and the dry air can flow from the outside toward the center of the hollow fiber membrane bundle housed in the housing. As a result, dry air collides with the hollow fiber membrane bundle and is turbulent, resulting in turbulent flow. In addition, by making it a deformed ellipse,
The packing density of the hollow fiber membrane is reduced, and the space between the hollow fiber membranes in the housing is increased, so that the contact area of the membrane with dry air, which is a dry gas, is improved. As a result, due to these synergistic effects, the dry air uniformly flows on the surface of each hollow fiber membrane housed in the housing, so that the dry air having a small moisture content is reduced through the hollow fiber membrane to the moisture content. The amount of water recovered (humidified amount) recovered from the off-gas with a large amount increases. In FIG. 12, the off-gas flows in a countercurrent to the flow of the dry air, but may flow in a parallel flow.

Here, the respective advantages when the dry air and the off-gas flow in countercurrent or cocurrent are described.
An advantage of flowing dry air and off-gas in countercurrent is that the difference in temperature concentration in the hollow fiber membrane can be made uniform, so that the water permeability is improved. Further, since the gas inlet and the outlet are opposed to each other, the layout of the gas pipe is improved. Furthermore, since the heat exchange rate by the hollow fiber membrane is improved, the cooling performance of the gas is improved, and since the heat exchange rate is high, it is easy to adjust the temperature of the outlet of the dry air to the temperature of the off gas, so that the temperature is controlled Becomes easier. Therefore, it becomes easy to control the humidity of the air supplied to the fuel cell. On the other hand, the advantage of flowing dry air and off-gas as co-current is that the dry air and off-gas have a high difference in humidity concentration at the inlet portion, so that the humidification efficiency is improved and the overall length of the hollow fiber membrane itself can be shortened. Since the apparatus can be downsized, it is easy to align and bundle the hollow fibers, which contributes to cost reduction.
Further, since the heat exchange rate of the dry air decreases, the temperature of the gas supplied to the fuel cell at the time of high output can be set higher. Therefore, the efficiency of the fuel cell can be improved.

Next, the temperature control function of the humidifier will be supplemented. For example, the temperature of dry air compressed by an air compressor such as a supercharger changes between approximately 30 ° C. (when the fuel cell is idling) and 120 ° C. (when the fuel cell is at maximum output). On the other hand, the fuel cell is operated at about 80 ° C. under temperature control, and off-gas of about 80 ° C. + α is discharged. When this off-gas and the dry air compressed by the air compressor are passed through a humidifier, heat transfer occurs together with moisture in the hollow fiber membrane, and the dry air reaches a temperature close to the off-gas (that is, a stable temperature close to the operating temperature of the fuel cell) Temperature)
Is supplied to the fuel cell as humidified air. That is, the dry air is supplied to the fuel cell after being humidified and heated by the humidifier at the time of low output such as when the fuel cell is idling, and humidified and cooled by the humidifier at the time of high output such as the maximum output of the fuel cell. It is supplied to the fuel cell as humidified air in a stable temperature range. Therefore, the fuel cell can be operated under suitable temperature conditions by the temperature control function of the humidifier, and the power generation efficiency of the fuel cell increases. Further, when an intercooler is attached to the discharge side of the air compressor, the dry air compressed by the air compressor is cooled (or heated) to approximately 50 ° C. (during fuel cell idling) to 60 ° C. (fuel (When the battery is at its maximum output). If the dry air that has passed through the intercooler is passed through a humidifier through which off-gas (80 ° C. + α) flows, the dry air is humidified and temperature-adjusted (heated) in the hollow fiber membrane, and has a temperature close to the off-gas, Humidified air in a stable temperature range close to the operating temperature of the fuel cell is supplied to the fuel cell. Therefore, even when the intercooler is attached, the fuel cell can be operated under suitable temperature conditions by the temperature control function of the humidifier, and the power generation efficiency of the fuel cell is increased.

By providing the turbulence generating structure on the inner wall surface of the housing 21a, the following effects can be obtained. (1) By providing grooves or projections on the inner wall surface of the housing or making the shape of the housing elliptical, turbulent flow is easily generated in the housing, so that dry air spreads over the entire outer surface of the hollow fiber bundle membrane. This eliminates the difference in moisture concentration in dry air depending on the position of the hollow fiber membrane module in the housing. As a result, the dry air can efficiently collect water and humidify the dry air uniformly. In addition, the amount (rate) of water recovered from dry air can be estimated. (2) By forming grooves on the inner wall surface of the housing, the weight of the entire hollow fiber membrane module can be reduced. In addition, the turbulence generation structures of the first to eighth embodiments described above can be appropriately combined as needed. When used in combination, stronger turbulence can be achieved, so that a larger amount of water can be recovered (humidified amount) from which dry air having a low water content can be recovered from the offgas having a high water content through the hollow fiber membrane.

[0039]

As is apparent from the above configuration and operation, (1) According to the first aspect of the present invention, the turbulence generating structure is provided on the inner wall surface of the housing, so that the inner wall surface is provided. The flow of the dry gas that has been rectified along the laminar flow collides with the turbulence generation structure on the inner wall surface and becomes turbulent,
Water recovery that allows the dry gas with low moisture content to be recovered from the wet gas with high moisture content through the water-permeable hollow fiber membrane by flowing evenly over the outer surface of the hollow fiber membrane bundle housed in the housing The amount (humidification amount) increases. (2) According to the second aspect of the present invention, by providing the groove on the inner wall surface of the housing, the flow of the dry gas rectified along the inner wall of the housing and flowing in the laminar flow is disturbed by the groove. It can be flow. As a result, the dry gas uniformly flows on the outer surface of the hollow fiber membrane bundle housed in the housing, and the dry gas having a low moisture content has a high moisture content through the water-permeable hollow fiber membrane. The amount of water recovery (humidification amount) that can be recovered from the wet gas increases. (3) According to the third aspect of the invention, by providing the projection on the inner wall surface of the housing, the flow of the dry gas can be disturbed by the projection to form a turbulent flow. As a result, the dry gas uniformly flows on the outer surface of the hollow fiber membrane bundle housed in the housing, and the dry gas having a low moisture content has a high moisture content through the water-permeable hollow fiber membrane. The amount of water recovery (humidification amount) that can be recovered from the wet gas increases. (4) According to the invention according to claim 4, the flow of the dry gas in the housing can be a swirling flow along the circumferential direction by making the shape of the housing bulged outward in an axisymmetric manner. Since the drying fluid can flow from the outside of the hollow fiber membrane bundle accommodated in the housing toward the center side, the dry gas collides with the hollow fiber membrane bundle and is disturbed to form a turbulent flow. As a result, the dry gas uniformly flows on the outer surface of the hollow fiber membrane bundle accommodated in the housing, so that the dry gas having a low moisture content is reduced through the water-permeable hollow fiber membrane to reduce the moisture content. The amount of water recovery (humidification amount) that can be recovered from a large amount of wet gas increases.

[Brief description of the drawings]

FIG. 1 is an overall configuration diagram of a fuel cell system to which a humidifier according to the present invention is applied.

FIG. 2 is an explanatory diagram schematically illustrating a configuration of the fuel cell of FIG. 1;

FIG. 3A is a perspective view illustrating a configuration of a humidifier according to the present invention. (B) It is a perspective view of the hollow fiber membrane module of the humidifier which concerns on this invention. (C) It is an enlarged view of the hollow fiber membrane of FIG.3 (b).

FIG. 4 is a cross-sectional view showing a gas flow in the humidifier according to the present invention.

FIG. 5 is a view showing a first embodiment of a turbulent flow generation structure in the humidifier according to the present invention.

FIG. 6 is a view showing a second embodiment of the turbulent flow generation structure in the humidifier according to the present invention.

FIG. 7 is a diagram showing a third embodiment of the turbulent flow generation structure in the humidifier according to the present invention.

FIG. 8 is a diagram showing a fourth embodiment of the turbulent flow generation structure in the humidifier according to the present invention.

FIG. 9 is a diagram showing a fifth embodiment of the turbulent flow generation structure in the humidifier according to the present invention.

FIG. 10 is a view showing a sixth embodiment of the turbulent flow generation structure in the humidifier according to the present invention.

FIG. 11 is a view showing a turbulence generation structure in a humidifier according to a seventh embodiment of the present invention.

FIG. 12 is a view showing an eighth embodiment of the turbulent flow generation structure in the humidifier according to the present invention.

FIG. 13 is a cross-sectional view showing a humidifier using a conventional hollow fiber membrane.

[Explanation of symbols]

2 Humidifier (humidifier for fuel cell) 21 Hollow fiber membrane module 21a Housing 21b Hollow fiber membrane bundle 21c _in dry air inlet 21c _out humidifier air outlet 21d _in off gas inlet 21d _out off gas outlet 22 one end distributor 22a Off gas outlet 22a 'Internal flow path 22b Dry air inlet 22b' Internal flow path 23 Other end distributor 23a Off gas inlet 23a 'Internal flow path 23b Humidified air outlet 23b' Internal flow path 31, 41, 51, 61, 71 Housing ( Cylindrical) 31a lattice-shaped linear groove 41a spiral groove 51a linear groove 61a annular groove 71a protrusion 81 housing (elliptical) 91 housing (deformed elliptical) 91 'housing (deformed elliptical)

 ──────────────────────────────────────────────────続 き Continued on the front page (72) Inventor Yoshio Kusano 1-4-1, Chuo, Wako, Saitama Prefecture Inside Honda R & D Co., Ltd. (72) Toshikatsu Katagiri 1-4-1, Chuo, Wako, Saitama F-term in Honda R & D Co., Ltd. (reference) 3L055 AA10 BA01 DA05 4D006 GA41 HA02 JA25A JA30A MA01 MB03 PB17 PB65 PC72 PC73 PC80 5H026 AA06 5H027 AA06 BA01 BA09 BA16

Claims (4)

[Claims] 1. A plurality of water-permeable hollow fiber membranes arranged along a longitudinal direction of a housing are housed in the housing,
In a humidifying device in which a gas having a different moisture content flows through the inside and the outside of the hollow fiber membrane to exchange moisture between the gases and humidify a dry gas having a small moisture content, the inner wall surface of the housing is disturbed. A humidifier having a flow generating structure. 2. The humidifier according to claim 1, wherein the turbulence generating structure has a groove provided on an inner wall surface of the housing. 3. The humidifier according to claim 1, wherein the turbulence generating structure has a projection on an inner wall surface of the housing. 4. The humidifier according to claim 1, wherein the turbulence generating structure has a shape in which the shape of the housing bulges outward in an axisymmetric manner. apparatus.