JP2005158429A - Hollow fiber membrane humidifier - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a hollow fiber membrane humidifier preventing flow out of non-recovered condensed water contained in offgas to an offgas exhaust port. <P>SOLUTION: The hollow fiber membrane humidifier has hollow fiber membrane modules 10a, 10b humidifying dry gas by moving water with the inside and the outside of a hollow fiber membrane, a housing container 20 housing the hollow fiber membrane modules 10a, 10b, and an offgas exhausting port 14 formed in a position other than a projection surface A in the central axis direction of the hollow fiber membrane modules 10a, 10b of the housing container 20. <P>COPYRIGHT: (C)2005,JPO&NCIPI

Description

  The present invention relates to a hollow fiber membrane humidifier that is installed in a fuel cell system mounted on a fuel cell vehicle or the like and humidifies air or the like as fuel.

  A fuel cell is a device that generates power using hydrogen gas and oxygen gas as fuel, and has been attracting attention from the viewpoint of protecting the global environment because exhaust gas is not generated along with power generation. Practical use is in progress.

  The fuel cell includes a fuel cell stack configured by stacking a plurality of single cells serving as a basic unit of power generation. For example, in a fuel cell using a solid polymer electrolyte membrane, a single cell has a membrane electrode assembly (MEA) in which an oxygen electrode and a hydrogen electrode are joined on both sides of the solid polymer electrolyte membrane. In addition, oxygen gas and hydrogen gas are respectively supplied to the oxygen electrode and the hydrogen electrode to generate electricity.

  In a fuel cell power generation system to which a fuel cell is applied, a cathode gas channel that supplies a cathode gas (air) containing oxygen gas to the fuel cell is provided, and a humidifier is installed on the cathode gas channel. The humidifier collects moisture contained in the off-gas generated by the reaction in the fuel cell, humidifies the cathode gas (air) with the collected moisture, and supplies the humidified cathode gas (air) to the fuel cell.

  An example of a humidifier for a fuel cell is a conventional cathode humidifier unit (see Patent Document 1).

A conventional cathode humidifier unit includes a plurality of hollow fiber membrane modules, an inlet head that connects the hollow fiber membrane modules in parallel to both ends of the hollow fiber membrane module in the longitudinal direction, and an outlet head. In the hollow fiber membrane module, a hollow fiber membrane bundle in which a number of tubular hollow fiber membranes made of a water permeable membrane are bundled is housed in a cylindrical housing. One end side of the housing of each hollow fiber membrane module is connected to an inlet head having an off-gas inlet, and the other end side is connected to an outlet head having an off-gas outlet. The inlet head and the outlet head are hollow fiber membranes. Formed on the central axis of the module. Drain outlets are respectively installed at the inlet head and the outlet head bottom, and the water accumulated at the inlet head and the outlet head bottom is drained.
JP 2002-184440 (page 8, FIG. 2)

  However, in the conventional cathode humidifier unit, the condensed water flowing from the fuel cell is not trapped by the humidifier and flows directly into the off-gas exhaust port. For this reason, combustion was incomplete in the hydrogen combustor installed downstream of the humidifier.

  In addition, when the fuel cell is installed in a low temperature environment, the condensed water flowing into the off-gas exhaust port will freeze and the valve will be fixed. Was getting bigger.

  The present invention has been made to solve the above-mentioned problems. That is, the hollow fiber membrane humidifier of the present invention is a hollow fiber that humidifies a dry gas by moving water between the inside and the outside of the hollow fiber membrane. The gist of the invention is to include a membrane module, a storage container for storing the hollow fiber membrane module, and an off-gas exhaust port formed at a position excluding the projection surface of the storage container in the central axis direction of the hollow fiber membrane module.

  According to the hollow fiber membrane humidifier of the present invention, the offgas exhaust port is formed in the storage container at a position excluding the projection surface in the central axis direction of the hollow fiber membrane module, so that the condensed water and the like contained in the offgas can be removed from the inner wall of the storage container It is possible to trap and prevent outflow of condensed water or the like from the off-gas exhaust port.

  Hereinafter, the hollow fiber membrane humidifier which concerns on embodiment of this invention is demonstrated using 1st Embodiment and 2nd Embodiment.

<First Embodiment (FIGS. 1 and 2)>
In the present embodiment, a hollow fiber membrane humidifier applied to a fuel cell system mounted on a fuel cell vehicle will be described as an example.

  FIG. 1 is a diagram showing a partial configuration of a fuel cell system mounted on a fuel cell vehicle. The fuel cell system is mounted under the floor of a fuel cell vehicle that is a moving body, and is used as a drive source for the fuel cell vehicle. As shown in FIG. 1, the fuel cell system 1 includes a fuel cell 2 having an anode (fuel electrode) and a cathode (oxidant electrode) as electrodes, and a hollow fiber membrane humidifier 3 on the downstream side of the fuel cell 2. The pressure regulating valve, the combustor 4 and the heat exchanger 5 are installed.

  The hollow fiber membrane humidifier 3 stores two cylindrical hollow fiber membrane modules described later in a storage container 20. An off gas introduction pipe 6 connected to the fuel cell 2 is connected to the upstream side of both ends of the storage container 20 and an off gas exhaust pipe 7 connected to the combustor 4 is connected to the downstream side of the hollow fiber membrane module. Connected.

  The storage container 20 perpendicular to the longitudinal direction of the hollow fiber membrane module is connected to a dry gas introduction pipe (air introduction pipe) 8 connected to a compressor (not shown), and the storage container to which the dry gas introduction pipe 8 is connected. A humidified gas exhaust pipe 9 connected to the fuel cell 2 is connected to the opposite side of the fuel cell 20.

  FIG. 2 is a diagram illustrating the configuration of the hollow fiber membrane humidifier 3, and (a) is a diagram schematically illustrating the configuration viewed from above. As shown in FIG. 2 (a), the hollow fiber membrane humidifier 3 houses two hollow fiber membrane modules 10a and 10b inside the storage container 20, and both ends of the hollow fiber membrane modules 10a and 10b in the longitudinal direction. In addition, an intake manifold 11 and an exhaust manifold 12 are formed. In the storage container 20, an offgas introduction port 13 is formed on the central axis of one hollow fiber membrane module 10 a, and the offgas introduction pipe 6 is connected to the offgas introduction port 13. In the storage container 20 on the exhaust manifold 12 side, an off-gas exhaust port 14 is formed on the central axis of the other hollow fiber membrane module 10b, and the off-gas exhaust port 14 is a hollow fiber having an off-gas introduction port 13 on the central axis. The off-gas exhaust pipe 7 is connected to the off-gas exhaust port 14 formed outside the axial projection plane A of the membrane module 10a. A condensed water drain port 15 is formed near the bottom of the exhaust manifold 12.

  FIG.2 (b) is a figure which shows the cross section of the transversal direction of the hollow fiber membrane humidifier which shows the position of the condensed water drain port 15 shown to Fig.2 (a). As shown in FIG. 2 (b), an off-gas introduction port 13 and an off-gas exhaust port 14 are formed on the central axes of the hollow fiber membrane module 10a and the hollow fiber membrane module 10b, and the hollow fiber membrane module 10a and the off-gas exhaust port 14 are formed. A condensed water drain port 15 is formed at the bottom of the exhaust manifold 12 between the two.

  Although the detailed configuration of the hollow fiber membrane module stored in the storage container 20 is not illustrated, basically, the hollow fiber membrane bundle fixedly placed in the cylindrical housing is stored, and the hollow fiber membrane bundle is It is formed by bundling a number of straw-shaped hollow fiber membranes. A plurality of dry gas introduction holes are formed on the outer circumferential surface of one end in the longitudinal direction of the housing on a straight line in the circumferential direction, and a plurality of humidified gas exhaust holes are formed on the outer circumferential surface of the other end on the straight line in the circumferential direction. It is formed. The off gas introduction pipe 6 and the off gas exhaust pipe 7 are connected to both ends in the longitudinal direction of the housing.

  Next, the operation of the hollow fiber membrane humidifier having the above configuration will be described. The unreacted air in the off-gas exhausted from the fuel cell and the water vapor generated by the chemical reaction of the fuel cell are distributed to some extent to the left and right hollow membrane modules 10a and 10b as shown by the arrow T1 in FIG. It is introduced into the hollow fiber membrane diameter. On the other hand, the gas discharged from the fuel cell includes a large amount of condensed water, liquid droplets, mist, and the like, which are liquid components. Since these condensed water, droplets, mist, and the like are heavy, inertia acts, and they travel substantially straight as indicated by an arrow T4 in FIG. For this reason, most of the condensed water, droplets, and mist flow into the hollow fiber membrane module 10a immediately below the offgas inlet 13 and do not enter the hollow fiber membrane module 10b. Further, since the off-gas inlet 13 is formed on the central axis of the hollow fiber membrane module 10a, the condensed water does not get trapped in the intake manifold and flows into the hollow fiber membrane module 10a. For this reason, condensed water can be utilized for humidification and humidification performance can be improved more. Water vapor, condensed water, droplets, mist and the like in the off-gas flowing into the hollow fiber membrane modules 10a and 10b permeate through the capillaries in the hollow fiber membrane and move to the outside of the hollow fiber membrane. On the other hand, a dry gas was introduced into the hollow fiber membrane modules 10a and 10b from a dry gas introduction pipe (air introduction pipe) 8 connected to a compressor (not shown) in FIG. Water that has flowed from the off-gas within the hollow fiber membrane diameter is recovered by flowing into the outside of the hollow fiber membrane in the housing from the plurality of dry gas introduction holes. The collected moisture is used to humidify the dry gas, and the humidified gas is exhausted to the outside of the hollow fiber membrane modules 10a and 10b through the humidified gas exhaust hole formed on the opposite side of the housing.

  The main flow of off-gas from which moisture has been separated flows toward the off-gas exhaust port 14 and is exhausted from the off-gas exhaust pipe 7 as indicated by an arrow T3 in FIG. As for the off gas, moisture is recovered in the hollow fiber membrane modules 10a and 10b, but unrecovered moisture is also included in the off gas. Condensed water, droplets, and the like in the unrecovered water in the hollow fiber membrane module 10a travel almost straight from the outlet in the hollow fiber membrane module 10a as indicated by arrow T4 due to their mass, and collide with the inner wall of the exhaust manifold 12. Trapped in a wall flow and descend downward. Condensed water, droplets, and the like that have become a wall flow in the exhaust manifold 12 flow in the exhaust manifold 12 as indicated by an arrow T5 in FIG. 2A, and do not remain in the exhaust manifold, and the condensed water drain port 15 Drained from.

  According to this embodiment, since the off-gas exhaust port is formed in the storage container at a position excluding the projection surface in the central axis direction of the hollow fiber membrane module, the condensed water can be trapped on the inner wall of the exhaust manifold. In addition, the trapped condensate is drained and recovered from the condensate drain port, preventing condensate outflow from the off-gas exhaust port, preventing entry into the combustor downstream of the hollow fiber membrane humidifier, and incomplete combustion. Can be prevented.

  Moreover, according to this embodiment, since the condensed water drain port was formed between the hollow fiber membrane module and the off-gas exhaust port, the condensed water can be easily recovered.

<Second Embodiment (FIG. 3)>
In the first embodiment described above, a hollow fiber membrane humidifier in which two hollow fiber membrane modules are stored in a storage container is illustrated, but in the present embodiment, an example in which one hollow fiber membrane module is stored is given. This will be described with reference to FIG. In addition, the same code | symbol is used for the same location as the hollow fiber membrane humidifier 3 shown in 1st Embodiment, and the description is abbreviate | omitted.

  FIG. 3 is a diagram illustrating the configuration of the hollow fiber membrane humidifier, and (a) is a diagram schematically illustrating the configuration as viewed from above. As shown in FIG. 3 (a), the hollow fiber membrane humidifier 16 houses the hollow fiber membrane module 10 inside the storage container 20, and the intake manifold 11 and the exhaust manifold are disposed at both ends of the hollow fiber membrane module 10 in the longitudinal direction. 12 is formed.

  In the storage container 20, an offgas introduction pipe 6 is connected to an offgas introduction port 13 formed on the central axis of the hollow fiber membrane module 10, and the offgas exhaust port 13 is projected on the projection surface B in the axial direction of the hollow fiber membrane module 10. It is formed in the position excluding. A condensate drain port 15 is formed between the hollow fiber membrane module 10 at the bottom of the exhaust manifold 12 and the off-gas exhaust port 14.

  In the hollow fiber membrane humidifier 16 configured as described above, the condensed water, droplets and mist contained in the off gas exhausted from the fuel cell flow into the hollow fiber membrane diameter of the hollow fiber membrane module 10 together with the off gas. The main flow of off-gas discharged from the hollow fiber membrane module 10 flows to the off-gas exhaust port 14 as shown by an arrow S1 in FIG. Then, the hollow fiber membrane module 10 collects moisture such as condensed water described in the first embodiment. Since the condensed water discharged from the hollow fiber membrane module 10 has a high mass, it travels substantially straight as indicated by an arrow S2 from the outlet of the hollow fiber membrane module 10 and collides with the inner wall of the exhaust manifold 12 to trap the condensed water. Then, the condensed water becomes a wall flow and descends downward. Condensed water that has become a wall flow flows as indicated by an arrow S3 and is drained through the condensed water drain port 15 without accumulating in the exhaust manifold 12.

  In the hollow fiber membrane humidifier 16 shown in FIG. 3, an example was given in which one hollow fiber membrane module 10 was installed in the storage container 20, but the hollow fiber membrane module 10 installed in the storage container 20 is As shown in the first embodiment, a plurality may be installed. For example, when two hollow fiber membrane modules 10 are installed in the storage container 20, as shown in FIG. 4, the projection plane C in the central axis direction of the hollow fiber membrane module 10 in which the off-gas introduction port 13 is formed is used. An off-gas exhaust port 14 is formed at a position to be removed.

  According to this embodiment, even when one hollow fiber membrane module is stored in the storage container, the condensed water trapped on the inner wall of the exhaust manifold can be recovered from the condensed water drain port, and from the off-gas exhaust port. The outflow of condensed water can be prevented. Further, even when a plurality of hollow fiber membrane modules are stored in the storage container, the outflow of condensed water from the offgas exhaust port can be prevented.

  In the present embodiment, an electric vehicle is cited as an example of a fuel cell vehicle. However, the hollow fiber membrane humidifier of the present invention is not limited to being mounted on a vehicle such as an electric vehicle. Of course, it can be applied to other organizations.

It is a figure which shows the structure of a part of fuel cell system which concerns on 1st Embodiment in this invention. It is a figure explaining the structure of the hollow fiber membrane humidifier shown in FIG. 1, (a) shows typically the structure seen from the upper surface, (b) is a side view. It is a figure explaining the structure of a hollow fiber membrane humidifier, (a) shows typically the structure seen from the upper surface, (b) is a side view. It is a side view which shows the structure of the hollow fiber membrane humidifier which concerns on 2nd Embodiment in this invention.

Explanation of symbols

1 ... Fuel cell system,
2 ... fuel cell,
3 ... Hollow fiber membrane humidifier,
4 ... combustor,
5 ... heat exchanger,
6 ... Off-gas introduction pipe,
7 ... Off-gas exhaust pipe,
8 ... Dry gas introduction pipe (air introduction pipe),
9 ... humidified gas exhaust pipe,
10a, 10b ... hollow membrane module,
11 ... Intake manifold,
12 ... Exhaust manifold,
13 ... off-gas inlet,
14: Off-gas exhaust port,
15 ... Condensate drain port,
16 ... Hollow fiber membrane humidifier,
20 ... storage container,

Claims (5)

A hollow fiber membrane module that humidifies the dry gas by moving water between the inside and outside of the hollow fiber membrane;
A storage container for storing the hollow fiber membrane module;
An off-gas exhaust port formed at a position excluding the projection surface in the central axis direction of the hollow fiber membrane module of the storage container;
A hollow fiber membrane humidifier comprising:   The hollow fiber membrane humidifier according to claim 1, further comprising a condensed water drain port formed between the hollow fiber membrane module of the storage container and the off-gas exhaust port.   The hollow fiber membrane humidifier according to claim 1 or 2, further comprising an offgas introduction port formed on the hollow fiber membrane module central axis of the storage container on the side facing the offgas exhaust port.   The hollow fiber membrane humidifier according to any one of claims 1 to 3, wherein one or two or more hollow fiber membrane modules are stored in the storage container. When two or more hollow fiber membrane modules are stored in the storage container,
The said off-gas exhaust port is formed in the position except the projection surface of the center axis direction of the hollow fiber membrane module which has arrange | positioned the said off-gas introduction port in the center axis direction. The hollow fiber membrane humidifier described in 1.

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