JP4441387B2 - Humidifier - Google Patents

Description

  The present invention relates to a humidifier, and more particularly, to a humidifier using a hollow fiber membrane.

  In recent years, fuel cells have attracted attention as power sources for electric vehicles. This fuel cell includes a so-called solid polymer fuel cell. In this polymer electrolyte fuel cell, a humidifier is used that exchanges moisture of off-gas, which is a wet gas discharged from the fuel cell, with a dry gas. As a humidifier used in such a fuel cell, a device with low power consumption is preferable. 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 type humidification, and nozzle injection, those using a hollow fiber membrane are suitably used as the humidifier used in the fuel cell. .

  A conventional humidifier using a hollow fiber membrane will be described with reference to FIG. 14. The humidifier 100 has a housing 101. The housing 101 is formed with a first inlet 102 for introducing dry air and a first outlet 103 for discharging dry air. The housing 101 is composed of a large number of, for example, 5000 hollow fiber membranes. The hollow fiber membrane bundle 104 is accommodated (for example, refer to Patent Document 1).

  Further, at both ends of the housing 101, fixing portions 105 and 105 ′ for fixing the both ends of the hollow fiber membrane bundle 104 in an open state are provided. A second inlet 106 for introducing wet air is formed outside the fixed part 105, and wet air from which moisture has been separated and removed by the hollow fiber membrane bundle 104 is formed outside the fixed part 105 '. A second outlet 107 for discharging is formed. Further, the fixing portions 105 and 105 ′ are covered with a first head cover 108 and a second head cover 109, respectively. The second inflow port 106 is formed in the first head cover 108, and the second outflow port 107 is formed in the second head cover 109.

  In the humidifying device 100 using the hollow fiber membrane configured as described above, when wet air is supplied from the second inlet 106 and passed through each hollow fiber membrane constituting the hollow fiber membrane bundle 104, the wet air is supplied. Moisture inside is separated by the capillary action of the hollow fiber membrane, permeates through the capillary of the hollow fiber membrane, and moves to the outside of the hollow fiber membrane. The moist air from which moisture has been separated is discharged from the second outlet 107.

On the other hand, dry air is supplied from the first inlet 102. Dry air supplied from the first inlet 102 flows outside the hollow fiber membranes constituting the hollow fiber membrane bundle 104. The water separated from the wet air has moved to the outside of the hollow fiber membrane, and the dry air is humidified by this water. The humidified dry air is discharged from the first outlet 103.
JP-A-7-71795

  However, in the conventional humidifier 100 shown in FIG. 14, the first inlet 102 for introducing dry air is formed at a position close to the center in the longitudinal direction of the housing 101. For this reason, most of the dry air passing through the outside of the hollow fiber membranes in the hollow fiber membrane bundle 104 accommodated in the housing 101 flows in the longitudinal center of the housing 101 as indicated by the black arrows. ing. Therefore, since the sufficient water exchange was not performed in the areas S and S near the end of the hollow fiber membrane bundle 104, the water recovery rate becomes lower than the permeated water amount in the hollow fiber membrane. There was a problem.

  Then, the subject of this invention is aiming at the improvement of a water recovery rate by enabling sufficient water exchange to be performed also in the edge part in the hollow fiber membrane bundle accommodated in the housing.

  The invention according to claim 1 of the present invention that has solved the above-described problems is that a large number of water-permeable hollow fiber membranes arranged along the longitudinal direction of the housing are accommodated in the housing, and the inside of the hollow fiber membranes. In the humidifying device that exchanges moisture between the gases by flowing gases having different moisture contents to the outside and humidifying the dry gas having a low moisture content, the hollow fiber is provided at a substantially central portion in the short direction of the housing. A bypass passage for allowing a gas flowing outside the membrane to pass therethrough is formed along a longitudinal direction of the housing, and the bypass passage has a larger diameter than the hollow fiber membrane, and the hollow fiber membrane is disposed in the bypass passage. An introduction port for introducing gas flowing outside and an exhaust port for discharging gas flowing outside the hollow fiber membrane are formed, and one end of the housing has an outside of the hollow fiber membrane inside the housing. Humidification characterized in that an inlet for introducing flowing gas and an outlet for discharging gas flowing outside the hollow fiber membrane from the housing are formed in the housing at the other end of the housing. Device.

In the invention which concerns on Claim 1, the bypass channel through which the gas which flows the outer side of a hollow fiber membrane passes is formed along the longitudinal direction of a housing. Since the bypass passage has a larger diameter than the hollow fiber membrane, the gas flowing outside the hollow fiber membrane introduced into the housing is introduced to the bypass passage. By passing through this bypass passage, the gas flowing outside the hollow fiber membrane can be sent into the housing. Accordingly, since gas can be supplied over the entire area of the bundle of hollow fiber membranes in the housing, moisture can be effectively exchanged even at the hollow fiber membrane at the end in the housing, thereby contributing to an improvement in water recovery rate. be able to.
The “substantially central portion in the short side direction of the housing” referred to in the present invention does not mean that it completely coincides with the central portion (axial center) in the short side direction of the housing, but is slightly shifted from the central portion. Is also included. Furthermore, what is necessary is just the state where the surrounding surface of a bypass channel is surrounded by the hollow fiber membrane.

  The invention according to claim 2 is the humidifier according to claim 1, wherein at least one of the introduction port and the discharge port is formed at an end portion of the bypass passage.

  The invention according to claim 3 is the humidifier according to claim 2, wherein the introduction port is formed at an end of the bypass passage.

  In the invention according to claim 4, a plurality of outlets for discharging the gas flowing outside the hollow fiber membrane are formed in the bypass passage, and the plurality of outlets are separated in the longitudinal direction of the bypass passage. It is arrange | positioned, It is a humidification apparatus of any one of Claims 1-3 characterized by the above-mentioned.

  In the invention according to claim 4, since a plurality of discharge ports are formed apart from each other in the longitudinal direction of the bypass passage, the gas that flows through the outside of the hollow fiber membrane almost uniformly in the longitudinal direction in the housing Can be discharged. For this reason, since the gas which flows outside the hollow fiber membrane can be supplied to almost the entire region of the hollow fiber membrane accommodated in the housing, moisture exchange can be performed in the entire hollow fiber membrane. Therefore, the water recovery rate can be further improved.

  According to a fifth aspect of the present invention, in any one of the first to fourth aspects, the inflow port and the outflow port are formed at positions facing each other across the bypass pipe. It is a humidification apparatus for fuel cells as described.

  In the invention which concerns on Claim 5, the inflow port and the outflow port of the gas which flow through the outer side of a hollow fiber membrane are formed in the position which opposes across a bypass channel. For this reason, the gas flowing outside the hollow fiber membrane introduced from the inflow port passes outside the hollow fiber membrane while moving in the short direction in the housing. Therefore, since the moving path of the gas flowing outside the hollow fiber membrane becomes longer, sufficient water exchange can be performed. Therefore, the water recovery rate is further improved.

  As described above, according to the first aspect of the present invention, the gas flowing outside the hollow fiber membrane can be sent into the housing by passing through the bypass passage. Therefore, since the gas flowing outside the hollow fiber membrane can be supplied over the entire area of the hollow fiber membrane bundle in the housing, moisture can be effectively exchanged even in the hollow fiber membrane at the end in the housing, Therefore, it can contribute to the improvement of the water recovery rate.

  According to the fourth aspect of the present invention, since the plurality of discharge ports are formed apart from each other in the longitudinal direction of the bypass pipe, the outside of the hollow fiber membrane flows substantially uniformly in the longitudinal direction in the housing. Gas can be discharged. For this reason, since the gas that flows outside the hollow fiber membrane can be supplied to almost the entire area of the hollow fiber membrane housed in the housing, water recovery can be performed in the entire hollow fiber membrane. Can be further improved.

  According to the invention which concerns on Claim 5, the gas which flows through the outer side of the hollow fiber membrane introduced from the inflow port passes the outer side of a hollow fiber membrane, moving to the transversal direction in a housing. Therefore, since the moving path of the gas flowing outside the hollow fiber membrane that moves outside the hollow fiber membrane becomes long, sufficient water exchange can be performed. Therefore, the water recovery rate can be further improved.

Hereinafter, embodiments of the present invention will be specifically described with reference to the drawings. FIG. 1 is an overall configuration diagram of the fuel cell system, and FIG. 2 is an explanatory diagram schematically showing the configuration of the fuel cell.
First, with reference to FIG. 1, 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.

  The fuel cell system FCS includes a polymer electrolyte 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 water. A methanol mixture storage tank (hereinafter referred to as “tank”) T or the like.

  The inside of the fuel cell 1 is divided into an oxygen electrode side 1a and a hydrogen electrode side 1b. Humidified air as an oxidant 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. Is supplied. Then, hydrogen and oxygen are chemically reacted through the electrolyte membrane to extract electric energy from the chemical energy to generate electric power.

  Humidified air is generated by compressing and humidifying air, which is a dry gas. Here, air is compressed by the air compressor 4 and humidification is performed by the humidifier 2. Humidification of the 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 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 is a raw fuel. Here, evaporation of the raw fuel is performed by the fuel evaporator 6, reforming is performed by the reformer 7, and CO removal is performed by the CO remover 8.

The raw fuel stored in the tank T is supplied to the fuel evaporator 6 via the pump P, the raw fuel gas evaporated by the fuel evaporator 6 is supplied to the reformer 7, and the CO remover 8 is modified. Fuel gas reformed by the mass device 7 is supplied. In the reformer 7, steam reforming and partial oxidation of methanol are performed in the presence of a catalyst. Further, the selective oxidation is carried out in the presence of a catalyst in the CO remover 8, CO is converted to CO _2. Since the CO remover 8 reduces the concentration of CO as much as possible, no. 1CO remover and No. 1 It consists of two 2CO removers. The CO remover 8 is supplied with air for selective oxidation from the air compressor 4.

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

  Next, the configuration and operation of the fuel cell that forms the core of the fuel cell system will be described with reference to FIG. The fuel cell 1 in FIG. 2 is schematically expressed as a single cell (actually, the fuel cell 1 is configured as a laminate in which about 200 single cells are stacked).

As shown in FIG. 2, the fuel cell 1 is divided into an oxygen electrode side 1a and a hydrogen electrode side 1b with an electrolyte membrane 13 in between, and electrodes each containing a platinum-based catalyst are provided on each side. An oxygen electrode 12 and a hydrogen electrode 14 are formed. Then, the humidified air humidified by the humidifier 2 as an oxidant gas is passed through the oxygen electrode side gas passage 11, and the hydrogen-rich fuel gas generated from the raw fuel is passed through the hydrogen electrode side gas passage 15. . As the electrolyte membrane 13, a solid polymer membrane, for example, a perfluorocarbon sulfonic acid membrane which is a proton exchange membrane is used as an electrolyte. The electrolyte membrane 13 has a large number of proton exchange groups in the solid polymer, exhibits a low specific resistance of 20 Ω-proton or less at room temperature when saturated with water, and functions as a proton conducting electrolyte. Therefore, protons generated by ionization of hydrogen at the hydrogen electrode 14 in the presence of the catalyst easily move through the electrolyte membrane 13 and reach the oxygen electrode 12. The protons that reach the oxygen electrode 12 immediately react with oxygen ions generated from oxygen in the humidified air in the presence of the catalyst to generate water. The generated water is discharged from the outlet on the oxygen electrode side 1a of the fuel cell 1 as an off gas which is a humid gas together with the humidified air. Note that electrons e ⁻ are generated when hydrogen is ionized at the hydrogen electrode 14, and the generated electrons e ⁻ reach the oxygen electrode 12 via an external load M such as a motor.

  The reason why the humidified humidified air is supplied to the fuel cell 1 as an oxidant gas is that when the electrolyte membrane 13 is dried, proton conductivity in the electrolyte membrane 13 is lowered and power generation efficiency is lowered. Therefore, humidification is important in the fuel cell system FCS using the solid polymer fuel cell 1.

Next, the humidifying device according to the first embodiment of the present invention will be described with reference to FIGS. 3 to 5. 3 to 11, the flow of off-gas which is “the gas flowing inside the hollow fiber membrane” of the present invention is indicated by white arrows, and “the gas flowing outside the hollow fiber membrane of the present invention” is shown. The flow of dry air (humidified air) is indicated by black arrows.
As shown in FIG. 3 (a), the humidifying device 2 according to the first embodiment has two hollow fiber membrane modules 21 each having a substantially cylindrical shape in parallel, and has a box-shaped one-end distributor 22 and It has the other end side distributor 23, and is made into the rectangular parallelepiped shape as a whole. The two hollow fiber membrane modules 21 and 21 are disposed and fixed horizontally at a predetermined interval by the one-end distributor 22 and the other-end distributor 23. Further, each of the hollow fiber membrane modules 21 and 21 is supplied with dry air via the one end side distributor 22 and discharges the wet off-gas, and humidified with the dry air via the other end side distributor 23. Humidified air is discharged and off-gas is supplied.

  As shown in FIG. 3B, the hollow fiber membrane module 21 has a housing 21a. As shown in FIGS. 4 and 5, the housing 21 a stores a hollow fiber membrane bundle 21 b configured by bundling water permeable hollow fiber membranes arranged along the longitudinal direction thereof. The hollow fiber membrane has a large number of fine capillaries with a diameter of several nanometers (nanometers) reaching from the inside to the outside, and in the capillaries, the vapor pressure is lowered and moisture condensation easily occurs. The condensed moisture is sucked out by capillary action, and the water passes through the hollow fiber membrane.

  The housing 21a has a hollow cylindrical shape with both ends open, and eight dry air inlets 21c, 21c... For introducing dry air into the housing 21a are spaced apart in the circumferential direction on one end side in the longitudinal direction. Is formed. On the other hand, on the other end side in the longitudinal direction of the housing 21a, eight humidified air outlets 21d, 21d... Serving as outlets for humidified humidified air are formed apart from each other in the circumferential direction.

Further, as shown in FIG. 5, a hollow bypass pipe 21e that forms a bypass passage through which dry air passes is disposed in the central portion in the short direction of the housing 21a. The inner diameter of the bypass pipe 21e is larger than that of the hollow fiber membrane, and is, for example, 1 cm to 5 cm in diameter. On the one end side of the bypass pipe 21e, a plurality of, for example, eight, inlets 21fa, 21fa,... For introducing dry air into the bypass pipe 21e are formed in the circumferential direction. The positions where the inlets 21fa, 21fa... Are formed are in the vicinity of one end in the longitudinal direction of the housing 21a. For this reason, the dry air introduced from the inlets 21fa, 21fa... Passes through the vicinity of one end in the longitudinal direction in the housing 21a. In addition, this edge part vicinity is specifically made into the position about 1 cm from the potting part 21g of the one end part side mentioned later. Moreover, it can also be set as the position of about 3 cm and 5 cm from the potting part 21g.
Further, on the other end portion side of the bypass pipe 21e, discharge ports 21fb, 21fb,... For discharging the dry air that has passed through the bypass pipe 21e are formed in a plurality of, for example, eight locations spaced apart in the circumferential direction. The positions where the discharge ports 21fb, 21fb,... Are formed are near the other end in the longitudinal direction of the housing 21a. For this reason, the dry air discharged | emitted from discharge port 21fb, 21fb ... will pass the longitudinal direction other end part vicinity in the housing 21a. Note that the vicinity of the end portion is specifically, for example, a position about 1 cm from the potting portion 21h on the other end side described later, like the one end portion side. Moreover, it can also be set as the position of about 3 cm and 5 cm from the potting 21h.

  Then, a part of the dry air introduced into the housing 21a from the dry air inlets 21c, 21c... Flows in the direction in which the dry air outlets 21d, 21d. Other dry air is introduced into the bypass passage in the bypass pipe 21e from the inlets 21fa, 21fa... Of the bypass pipe 21e. The dry gas introduced into the bypass pipe 21e passes through the bypass pipe 21e and is discharged from the discharge ports 21fb, 21fb.

  On the other hand, the hollow fiber membrane bundle 21b accommodated in the housing 21a is a bundle of a large number of, for example, thousands of water permeable hollow fiber membranes having hollow passages, with a potting portion 21g on one end side and a potting portion on the other end side. Potting is performed so as to provide 21h. The potting portion 21g provided on one end portion side of the housing 21a is located slightly on the end portion side from the position where the dry gas inflow ports 21c and 21c are formed.

  An off-gas outlet 21j is formed outside the potting part 21g, while an off-gas inlet 21i is formed further outside the potting part 21h. Thus, when the potting portions 21g and 21h are separated, the off gas inlet 21i and the off gas outlet 21j communicate with the inside of each hollow fiber membrane forming the hollow fiber membrane bundle 21b, and the off gas flow with the outside of each hollow fiber membrane. The inlet 21i and the off-gas outlet 21j are kept airtight, and the off-gas flowing through the hollow passage inside the hollow fiber membrane and the dry air flowing outside the hollow fiber membrane are not mixed. Further, the off gas flowing in from the off gas inlet 21i is distributed to each hollow fiber membrane at a position outside the potting portion 21h, and the off gas discharged from each hollow fiber membrane is collected at a position outside the potting 21g. It is like that. In such a hollow fiber membrane module 21, a bundle of a predetermined number of hollow fiber membranes is inserted into the housing 21a, and the potting portions 21g and 21h are formed by sufficiently adhering and fixing the vicinity of both end surfaces with an adhesive. It is created by cutting and removing a bundle of hollow fiber membranes along both ends.

  On the other hand, the one end side distributor 22 fixes the two hollow fiber membrane modules 21 and 21 together with the other end side distributor 23 in a predetermined positional relationship. The one-end distributor 22 has an off-gas outlet 22a and a dry air inlet 22b. As shown in FIGS. 4A and 4B, the off-gas outlet 22a communicates with the off-gas outlet 21j of each of the hollow fiber membrane modules 21 and 21 through an internal flow path 22a 'disposed inside the one-end distributor 22. is doing. Further, as shown in FIGS. 4A and 4C, the dry air inlet 22b is connected to one end side of each hollow fiber membrane module 21, 21 by an internal flow path 22b 'disposed inside the one end distributor 22. Are connected to the dry air inlets 21c, 21c.

  On the other hand, an off-gas inlet 23a and a humidified air outlet 23b are formed in the other end distributor 23. As shown in FIG. 4A, the off-gas inlet 23a is connected to the off-gas inlet 21i of each of the hollow fiber membrane modules 21 and 21 by an internal flow path 23a ′ disposed inside the other end distributor 23. . Further, the humidified air outlet 23b is provided with dry air outlets 21d, 21d, ... formed on the other end side of the hollow fiber membrane modules 21, 21 by an internal flow path 23b 'disposed inside the other end distributor 23. Communicated with.

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

Next, the operation of the humidifier 2 according to the present invention will be described with reference to FIGS.
The off gas, which is a wet gas, flows into the humidifier 2 from the off gas inlet 23a of the other end distributor 23 shown in FIGS. The off gas flowing into the other end distributor 23 reaches the off gas inlet 21i of the hollow fiber membrane module 21 via the internal flow path 23a '. The off gas that has flowed into the housing 21a via the off gas inlet 21i branches toward the hollow fiber membranes in the hollow fiber membrane bundle 21b and flows through the inside thereof. The off gas that has flowed through the inside of the hollow fiber membrane exits each hollow fiber membrane and flows out from the off gas outlet 21j. The off-gas flowing out from the off-gas outlet 21j flows through the internal passage 22a ′ of the one-end distributor 22 and joins. Then, the gas reaches the off-gas outlet 22a, is discharged from the off-gas outlet 22a, and goes to the gas-liquid separator 3 at the subsequent stage.

  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 distributor 22 and is distributed via the internal flow path 22b 'to one end of each hollow fiber membrane module 21, 21. Are introduced into the housing 21a through the dry air inlets 21c, 21c. The dry air introduced into the housing 21a flows outside the hollow fiber membrane. At this time, dry air flows through the outside of the hollow fiber membrane, and off-gas flows through the inside of the hollow fiber membrane, and moisture is separated from the off-gas by the hollow fiber membrane. With the separated moisture, the dry air flowing outside the hollow fiber membrane is humidified to become humidified air.

  This will be further described. An off gas containing a large amount of water is passed through the inside of the hollow fiber membrane, and a dry air containing relatively little water is passed through the outside. Then, moisture in the off-gas is condensed inside the hollow fiber membrane, and moisture is evaporated by dry air outside. At the same time, off-gas moisture condensed inside is supplied by capillary action from the inside to the outside of the hollow fiber membrane. Thereby, humidification of the dry air which flows outside the hollow fiber membrane is performed. That is, in the hollow fiber membrane, water permeation (water separation) is performed using the difference in the moisture content of the gas flowing inside and outside the hollow fiber membrane as a driving force.

  The humidified air thus obtained is discharged from the dry air outlets 21d, 21d, ... toward the internal flow path 23b 'in the outlet side distributor 23. In the internal flow path 23b ', the humidified air discharged from the hollow fiber membrane module 21 is collected and directed to the humidified air outlet 23b, and then supplied to the gas-liquid separator 3 at the subsequent stage via the humidified air outlet 23b.

  In this way, moisture is exchanged between the off-gas and the dry air. In the present invention, as shown by the black arrows in FIG. 5, the water is introduced into the housing 21a from the dry air inlets 21c and 21c. A part of the dry air flows through the outside of the hollow fiber membrane between the hollow fiber membrane bundles 21b as it is and moves toward the dry air outlets 21d, 21d,. On the other hand, the remainder of the dry air introduced into the housing 21a flows into the bypass pipe 21e through the inlets 21fa and 21fa. In the bypass pipe 21e, since the resistance value is lower than the outside of the bypass pipe 21e, the dry air easily moves to the discharge ports 21fb, 21fb,. In this way, the dry air that has moved to the positions of the discharge ports 21fb, 21fb,... Is discharged from the discharge ports 21fb, 21fb,.

  As described above, the dry air introduced from the dry air inlets 21c, 21c,... Passes through the outer sides of the hollow fiber membranes between the hollow fiber membrane bundles 21b and travels toward the dry air outlets 21d, 21d,. Of the hollow fiber membrane bundle 21b accommodated therein, moisture exchange is mainly performed in the central portion in the longitudinal direction. On the other hand, the dry air that has passed through the bypass pipe 21e undergoes moisture exchange mainly in the areas S and S at both ends in the longitudinal direction of the hollow fiber membrane bundle 21b housed in the housing 21a. For this reason, it is possible to distribute the dry air almost uniformly throughout the entire area of the housing 21a. Therefore, water exchange can be performed almost uniformly in the entire hollow fiber membrane bundle 21b, so that the water recovery rate can be improved.

Next, a second embodiment of the present invention will be described with reference to FIGS.
7 is a side sectional view of the hollow fiber membrane module according to the second embodiment, FIG. 8A is a sectional view taken along line XX of FIG. 7, and FIG. 7B is a sectional view taken along line YY of FIG. It is. In addition, since this embodiment has a part which is common in the first embodiment, a part different from the first embodiment will be mainly described, and a part which is common to the first embodiment will be described in the drawing. The same reference numerals are assigned and description thereof is omitted.

  As shown in FIGS. 7 and 8, the hollow fiber membrane module 31 according to the present embodiment has a bypass pipe 31 e that forms a bypass passage in the housing 21 a as a configuration different from the first embodiment. Yes.

  The bypass pipe 31e is provided with an introduction pipe 31fa that directly introduces dry air into the bypass pipe 31e from the dry air inlet 22b of the one-end distributor 22. Further, the bypass pipe 31e is formed with a large number of discharge ports 31fb, 31fb..., And these discharge ports 31fb, 31fb... Are spaced apart from each other in the longitudinal direction of the bypass pipe 31e. Other configurations are substantially the same as those in the first embodiment.

The operation of the present embodiment having such a configuration will be described.
In the present embodiment, the dry air that has passed through the internal flow path 22b 'in the one-end distributor 22 is introduced into the housing 21a from the dry air inlets 21c, 21c, ... in the housing 21a. At the same time, the dry air passes through the introduction pipe 31fa and is introduced into the bypass pipe 31e.

  The dry air introduced from the dry air inlets 21c, 21c... Moves directly toward the dry air outlet 21d in the housing 21a. On the other hand, the dry air introduced into the bypass pipe 31e is discharged to the outside of the bypass pipe 31e from a large number of discharge ports 31fb, 31fb, ... spaced apart in the longitudinal direction of the bypass pipe 31e. Since these many discharge ports 31fb, 31fb,... Are spaced apart in the longitudinal direction of the bypass pipe 31e, the dry air introduced through the bypass pipe 31e is at the longitudinal center and end of the housing 21a. The entire area in the housing 21a is spread to the corresponding areas S and S.

  For this reason, the hollow fiber membrane bundle 21b and the dry air can exchange moisture also at both ends and the center in the longitudinal direction of the housing 21a. Therefore, since water can be sufficiently exchanged in the entire region from the both end portions to the central portion of the hollow fiber membrane 21b, the water recovery rate can be improved.

  In this way, the dry air introduced from the dry air inlets 21c, 21c... And the discharge ports 31fb, 31fb... Of the bypass pipe 31e to the outer portion of the hollow fiber membrane in the housing 21a flows outside the hollow fiber membrane. At this time, the dry air is humidified by the moisture of the off-gas flowing through the hollow fiber membrane to become humidified air. And it is discharged | emitted from the humidification air exit 23b, and is supplied to the gas-liquid separation apparatus 3 of the back | latter stage shown in FIG. 1 through an appropriate flow path.

Next, a third embodiment will be described with reference to FIG.
FIG. 9 is a side sectional view of the hollow fiber membrane module according to the third embodiment. Also in this embodiment, the same parts as those in the first embodiment are denoted by the same reference numerals, and the description thereof is omitted.

  As shown in FIG. 9, in the hollow fiber membrane module 41 according to the present embodiment, the longitudinal center portion of the housing 41a is constricted toward the axial center direction. Due to this constriction, the central portion in the longitudinal direction of the hollow fiber membrane bundle 41b accommodated in the housing 41a is in the axial center direction. Other parts are the same as those in the first embodiment.

  In this embodiment having such a configuration, as in the first embodiment, dry air is introduced into the housing 41a from the dry air inlets 21c, 21c..., And part of the dry air flows in the direction of the dry air outlets 21d and 21d. Move directly. The other part of the dry air is introduced into the bypass pipe 21e from the introduction ports 21fa, 21fa, ... formed on one end side of the bypass pipe 21e. The dry air introduced into the bypass pipe 21e is discharged from discharge ports 21fb, 21fb ... formed on the other end side of the bypass pipe 21e.

  Here, in this embodiment, the longitudinal direction center part of the housing 41a is constricted toward the axial center direction. Therefore, since the cross-sectional area of the hollow fiber membrane bundle 41b at the portion through which the dry air introduced from the dry air inlets 21c, 21c... Passes is small, the dry air easily spreads over the entire hollow fiber membrane bundle 41b.

Furthermore, a fourth embodiment will be described with reference to FIG.
FIG. 10 is a side sectional view of a hollow fiber membrane module according to the fourth embodiment. Also in this embodiment, the same parts as those in the first embodiment are denoted by the same reference numerals, and the description thereof is omitted.

  As shown in FIG. 10, in the hollow fiber membrane module 51 according to the present embodiment, a bypass pipe 51e is disposed in the housing 21a. The bypass pipe 51e is provided with a large-diameter introduction pipe 51fa that introduces dry air into the bypass pipe 51e. In the present embodiment, a dry air inlet for directly introducing dry air into the housing 21a is not formed. For this reason, all the dry air that has passed through the internal flow path 22b 'of the one-end distributor 22 is introduced into the bypass pipe 51e.

  Further, the bypass pipe 51e is formed with a plurality of discharge ports 51fb, 51fb..., And these discharge ports 51fb, 51fb... Are spaced apart in the longitudinal direction of the bypass pipe 51e. Other parts are the same as those in the first embodiment.

  In the present embodiment having such a configuration, dry air is introduced into the bypass pipe 51e from the introduction port 51fa in the bypass pipe 51e. The dry air introduced into the bypass pipe 51e is discharged toward the hollow fiber membrane bundle 21b accommodated in the housing 21a from a plurality of discharge ports 51fb, 51fb, ... formed in the longitudinal direction of the bypass pipe 51e. Is done. At this time, a plurality of the discharge ports 51fb, 51fb... Are formed apart from each other in the longitudinal direction of the bypass pipe 51e, so that dry air can be supplied over the entire area of the hollow fiber membrane bundle 21b. Therefore, since water can be sufficiently exchanged in the entire area of the hollow fiber membrane 21b, the water recovery rate can be improved.

Next, a fifth embodiment will be described with reference to FIG.
FIG. 11 is a side sectional view of a hollow fiber membrane module according to the fifth embodiment. Also in this embodiment, the same parts as those in the first embodiment are denoted by the same reference numerals, and the description thereof is omitted.
As shown in FIG. 11, the hollow fiber membrane module 61 according to the present embodiment has a dry air inlet 61c on one end side of the housing 21a and a dry air outlet 61d formed on the other end side. It is formed one by one. Further, the dry air inlet 61c and the dry air outlet 61d are disposed at positions facing each other across the bypass pipe 21e.

  By having such a configuration, in the present embodiment, the dry air discharged from the discharge ports 21fb, 21fb... Of the bypass pipe 21e spreads in the short direction in the housing 21a. Accordingly, the movement path of the dry gas flowing through the housing 21a becomes long, the dry air stays in the housing 21a, and the contact time with the hollow fiber membranes constituting the hollow fiber membrane bundle 21b becomes long. Moisture exchange can be performed. Therefore, it can contribute to the improvement of the water recovery rate.

  On the other hand, in each said embodiment, although the bypass pipe was arrange | positioned in the transversal center part of the housing, it is not essential to arrange | position in this position. For example, as shown in FIG. 12, the bypass pipe 21e disposed at the center position indicated by the phantom line can be slightly offset downward. In addition, although not shown in the drawing, it is of course possible to adopt an aspect in which they are offset upward, laterally, or obliquely.

  Alternatively, it is not necessary to have only one bypass pipe. For example, as shown in FIG. 13 (a), two bypass pipes 21e and 21e can be provided, and as shown in FIG. 13 (b), three bypass pipes 21e, 21e and 21e are provided. It can also be arranged.

  The preferred embodiments of the present invention have been described above, but the present invention is not limited to the above-described embodiments. For example, although off gas and dry air are made to flow countercurrently in the housing, it is also possible to adopt a mode in which they are made to flow in parallel.

  At this time, as an advantage of using dry air and off-gas as countercurrent, the difference in humidity concentration in the hollow fiber membrane can be made uniform, so that the water permeation efficiency is improved. Further, since the gas inlet and the outlet face each other, the layout of the gas pipe is improved. Furthermore, since the heat exchange efficiency by the hollow fiber membrane is improved, the gas cooling performance is improved. In addition, 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 outlet of the off gas, so that the temperature can be easily adjusted. Therefore, it becomes easy to manage the humidity of the air supplied to the fuel cell.

Here, it supplements about the temperature control function which a humidifier has.
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) to 120 ° C. (when the fuel cell is at its 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. If this off-gas and dry air compressed by the air compressor are passed through a humidifier, moisture transfer and heat transfer occur in the hollow fiber membrane, and the dry air is at a temperature close to that of the off-gas (that is, the stability close to the operating temperature of the fuel cell). ) And is supplied to the fuel cell. That is, the dry air is humidified and heated by the humidifier when the output is low, such as when the fuel cell is idling, and is supplied to the fuel cell, and is humidified and cooled by the humidifier when the output is high, such as the maximum output of the fuel cell. The fuel cell is supplied as humidified air in a stable temperature range. Therefore, the fuel cell can be operated under suitable temperature conditions by the temperature adjustment function of the humidifier, and the power generation efficiency of the fuel cell is increased.

  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), and is approximately 50 ° C. (during fuel cell idling) to 60 ° C. (fuel) The temperature changes between the maximum output of the battery. 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-controlled (heated) in the hollow fiber membrane, that is, a temperature close to the off gas, that is, The 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 a suitable temperature condition by the temperature adjustment function of the humidifier, and the power generation efficiency of the fuel cell is increased.

  On the other hand, the merit of making dry air and off-gas flow in parallel is that the humidity concentration difference between the dry air and off-gas at the inlet is high, so the humidification efficiency improves, so the overall length of the hollow fiber membrane itself can be shortened. It contributes to miniaturization. Moreover, since the apparatus can be reduced in size, it becomes easy to align and bundle the hollow fibers, which contributes to cost reduction. Furthermore, since the heat exchange rate of the dry air is lowered, the gas temperature supplied to the fuel cell at high output can be set higher. Therefore, the efficiency of the fuel cell can be improved.

  Moreover, although the humidification apparatus is provided with two hollow fiber membrane modules, it cannot be overemphasized that one or other numbers may be sufficient. Further, in each of the above embodiments, “gas flowing through the inside of the hollow fiber membrane” is off-gas and “gas flowing through the outside of the hollow fiber membrane” is dry air. However, these can be reversed. .

  In addition, when moisture condenses in a portion of the housing such as a hollow fiber membrane module through which dry air (humidified air) flows, it becomes impossible to effectively utilize the outer surface area of the hollow fiber membrane. There is a fear. Therefore, it is preferable that the humidified air can be extracted from below the hollow fiber membrane module or the like so that water does not accumulate in the housing. By doing in this way, the condensed water can be easily extracted from the inside of the housing together with the humidified air, and the occurrence of a water pool is prevented. The extracted water is preferably collected by a catch tank or the like and reused by being sent to another system.

1 is an overall configuration diagram of a fuel cell system. It is explanatory drawing which modeled the structure of the fuel cell. (A) is a perspective view which shows the humidification apparatus which concerns on this invention, (b) is a perspective view of a hollow fiber membrane module. (A) is a sectional side view of the humidifier according to the present invention, (b) is a sectional view taken along line XX of (a), and (c) is a sectional view taken along line YY of (a). It is a sectional side view of the hollow fiber membrane module which concerns on 1st Embodiment. (A) is the XX sectional view taken on the line of FIG. 5, (b) is the YY sectional view taken on the line of FIG. It is a sectional side view of the hollow fiber membrane module which concerns on 2nd Embodiment. (A) is the XX sectional view taken on the line of FIG. 7, (b) is the YY sectional view taken on the line of FIG. It is a sectional side view of the hollow fiber membrane module which concerns on 3rd Embodiment. It is a sectional side view of the hollow fiber membrane module which concerns on 4th Embodiment. It is a sectional side view of the hollow fiber membrane module which concerns on 5th Embodiment. It is a longitudinal cross-sectional view which shows the modification of the hollow fiber membrane module which concerns on 1st Embodiment. (A) is a longitudinal cross-sectional view which shows the modification of the hollow fiber membrane module which concerns on 1st Embodiment, (b) is a longitudinal cross-section which shows the other modification of the hollow fiber membrane module which concerns on 1st Embodiment. FIG. It is a sectional side view of the conventional humidifier.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Fuel cell 2 Humidifier 21a Housing 21b Hollow fiber membrane bundle 21c Dry air inflow port 21d Dry air outflow port 21e Bypass pipe (bypass passage)
21fa inlet 21fb outlet 21i offgas inlet 21j offgas outlet FCS fuel cell system

Claims (5)

A large number of water-permeable hollow fiber membranes arranged along the longitudinal direction of the housing are accommodated in the housing, and gases having different moisture contents are passed through the inside and outside of the hollow fiber membranes so that moisture is contained between the gases. In a humidifier that exchanges and humidifies dry gas with low moisture content,
A bypass passage that allows a gas flowing outside the hollow fiber membrane to pass through is formed along a longitudinal direction of the housing at a substantially central portion in a short direction of the housing,
The bypass passage has a larger diameter than the hollow fiber membrane,
An introduction port for introducing gas flowing through the outside of the hollow fiber membrane into the bypass passage and a discharge port for discharging gas flowing through the outside of the hollow fiber membrane are formed,
An inlet for introducing a gas that flows outside the hollow fiber membrane into the housing at one end of the housing, and a gas that flows outside the hollow fiber membrane from the housing to the other end of the housing. A humidifier characterized in that an outlet for discharging is formed in the housing.   The humidification device according to claim 1, wherein at least one of the introduction port and the discharge port is formed at an end portion of the bypass passage.   The humidifier according to claim 2, wherein the introduction port is formed at an end of the bypass passage.   A plurality of outlets for discharging gas flowing outside the hollow fiber membrane are formed in the bypass passage, and the plurality of outlets are arranged apart from each other in the longitudinal direction of the bypass passage. The humidifying device according to any one of claims 1 to 3. The humidifier according to any one of claims 1 to 4, wherein the inflow port and the outflow port are formed at positions facing each other across the bypass pipe.

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