JPH0232201B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION (a) Field of Industrial Application The present invention relates to a metal hydride container for storing hydrogen or storing heat by utilizing dehydrogenation and hydrogenation reactions of metal hydrides.

(b) Prior art In this type of metal hydride container, the metal hydride powder becomes finer as it undergoes repeated dehydrogenation and hydrogenation reactions, and its thermal conductivity further decreases, making the reaction more rapid. It stops progressing. Note that a metal hydride becomes a metal by dehydrogenation, and in this specification, this case is also referred to as a metal hydride.

Therefore, in order to promote the dehydrogenation and hydrogenation reactions of metal hydrides and improve the reaction efficiency, it is necessary to improve the thermal conductivity between the heat medium and the metal hydride.

Conventionally, measures have been taken to improve this thermal conductivity, such as arranging fins in a powder-packed bed of metal hydride, but this was far from sufficient.

Therefore, as a result of repeated research to improve this point, the applicant found that it was effective to use foam metal as the fin, and proposed it earlier. According to this, the metal hydride powder and the foamed metal are mixed together, and the distance between the metal hydride powder and the foamed metal as heat transfer fins becomes extremely short on average, and the metal hydride powder is spread over the entire metal hydride. As a result, heat exchange has become more uniform, and the efficiency of using metal hydrides has improved.

However, since the manufacturing process of foamed metal includes a process of heating and vaporizing the foamed synthetic resin, a thick oxide film is formed on the surface of the manufactured foamed metal, resulting in a decrease in thermal conductivity. For this reason, even in metal hydride containers using this foamed metal, there was a problem in that the heat exchange efficiency was not improved as much as expected.

(c) Problems to be Solved by the Invention An object of the present invention is to further improve the previously proposed present invention and provide a metal hydride container with even better heat exchange efficiency.

(d) Means for solving the problem Therefore, in the present invention, the thick oxide film on the surface is removed by subjecting the nickel foam to surface treatment such as acid cleaning before use, and then the heat transfer properties are improved. It is characterized in that the surface is plated with high quality silver or copper, and this is packed together with metal hydride into a metal hydride container.

(E) Effect It is effective to plate copper or silver as is on a foam metal whose surface is covered with an oxide film, but after removing the oxide film of the foam metal through surface treatment,
By plating silver or copper, which is a good heat conductive material,
The thermal conductivity is further improved, and the heat exchange efficiency between the metal hydride and the heat medium is improved.

(f) Examples Examples of the present invention will be described below with reference to the drawings.

FIG. 1a is a side sectional view of a metal hydride container according to an embodiment of the present invention, and FIG. 1b is a sectional view taken along line A-A. In FIG. 1, at the flange side end of a cylindrical pipe 1 having a flange portion 1a at one end, a closing disk 3 having a heat medium inlet/outlet conduit 2a at the center is provided with bolts 4,
It is connected to the flange portion on the side of the pipe 1 with a nut 5. Further, at the other end of the cylindrical pipe 1, a closing disk 7 having a heat medium inlet/outlet conduit 2b at the center and a hydrogen inlet/outlet conduit 6 is fitted and fixed.
These cylindrical pipe 1, closing disk 3, closing disk 7
The part of the cylindrical pressure-resistant container 20 composed of
A cylindrical heat medium pipe 2c communicating with the heat medium inlet/output pipes 2a and 2b is provided, and these pipes 2
a, 2c, and 2b integrally form the cylindrical pressure vessel 2.
0 is formed.

A heat insulating material 8 is pasted on the inner wall of the cylindrical pressure-resistant container 20, and the inner surface has filter plates 9 and 10 at both ends that allow hydrogen to pass through but not metal hydride powder. cylindrical pipe 1
A filter cylinder 40 formed by 1 is provided.

Further, in this embodiment, a readily available nickel foam 12 and a metal hydride powder 13 are used as a foamed metal body between the filter cylinder 40 and the heat medium pipe 30.
is filled.

In this way, the cylindrical pressure vessel 20, the heat medium pipe 3
0. By constructing the filter cylindrical body 40 by assembling each part, maintenance such as replacement of the metal hydride powder 13 inside can be facilitated.

As shown in the enlarged cross-sectional view of FIG. 2, the shape of the nickel foam 12 is more like a loofah scrubber made of intertwined metal fibers than a sponge. However, it goes without saying that it is not limited to this shape. In addition, 12a in FIG. 2 indicates a metal part, 12b indicates a space part,
This space portion 12b is filled with metal hydride powder 13.

However, although this nickel foam 12 is easily available, its thermal conductivity is one order of magnitude lower than that of copper, silver, etc. Moreover, as described above, a thick oxide film is formed on the surface during the manufacturing process. Therefore, even if used as is, the heat exchange efficiency will not be improved that much. Therefore, in this embodiment, the nickel foam is subjected to surface treatment such as acid cleaning to remove the oxide film on the surface.
Alternatively, the surface of the nickel foam is plated with silver or copper, which has excellent thermal conductivity. Furthermore, after surface treatment is performed in advance to remove the oxide film on the surface, silver or copper, which has good thermal conductivity, is plated.

Figure 3 shows the temperature rise characteristics of the cylindrical pressure vessel 20 at this time, where the solid line A is the temperature rise characteristic curve when untreated nickel foam is used, and the broken line B is the surface treatment to remove the oxide film. The temperature rise characteristic curve when using a nickel foam that has been treated, the one-dot chain line C is the temperature rise characteristic curve when using a nickel foam with copper plating on the untreated surface, and the two-dot chain line D shows the temperature rise characteristic curve when using a nickel foam that has been surface treated to remove the oxide film. This is a temperature rise curve when using copper-plated nickel foam.

As is clear from this figure, by surface-treating or plating the nickel foam, the thermal conductivity of the nickel foam improves by several percent, and the metal hydride powder to be filled into the cylindrical pressure-resistant container 20 13
The heat exchange coefficient between the heat medium and the heat medium flowing through the heat medium pipe 30 is improved.

The nickel foam 12 filled between the filter cylinder 40 and the heat medium pipe 30 may be divided into small pieces as shown in the above embodiment, or may be formed integrally as shown in FIG. It's okay to be. In the figure, 12c is a through hole into which the heat medium pipe 2c is fitted.

As shown in the side cross-sectional view of FIG. 5a and the BB cross-sectional view of FIG. Moreover, it is preferable to form fins 2d along the axial direction on the outside of the heat medium pipe 2c.

In this manner, by using the filter cylinder 40 whose entire structure is a filter, the effective area of the filter is expanded, and hydrogen exchange with the metal hydride powder 13 is uniformly performed. In addition, heat medium pipe 2
By forming the fins 2d on the outside of the fins 2d, heat transfer between the nickel foam and the heating medium can be carried out effectively.

(G) Effects of the Invention As described above, according to the present invention, the metal hydride container contains a surface-treated foamed metal body that has been plated with silver or copper after removing the surface oxide film of the nickel foam, as well as a metal hydride. Since the powder is filled, the heat exchange efficiency between the heating medium and the metal hydride powder is improved. Furthermore, since the entire inner surface of the pressure-resistant container is covered with a heat insulating material, sensible heat loss can be reduced. Further, since the metal hydride is housed within the filter cylinder, the reaction between the metal hydride and hydrogen can be uniformly carried out.

[Brief explanation of drawings]

Fig. 1 is a configuration diagram of a metal hydride container according to an embodiment of the present invention, in which Fig. 1a is a side view thereof, Fig. 1b is a sectional view taken along line A-A, and Fig. 2 is a diagram showing a container for storing metal hydride inside the container. A cross-sectional view of a nickel foam, Figure 3 shows each temperature rise characteristic curve of a pressure container when using a nickel foam under various conditions, and Figure 4 shows another example of a nickel foam housed in a pressure container. 5 is a configuration diagram of a metal hydride container according to another embodiment of the present invention, and FIG. 5A is a side sectional view thereof, and FIG.
-B sectional view. 1... Cylindrical pipe, 1a... Flange part, 2
a, 2b... Heat medium inlet/output conduit, 2c, 30... Heat medium pipe, 2d... Fin, 3, 7... Closing disk, 4...
...Bolt, 5...Nut, 6...Hydrogen inlet/output pipe,
8...Insulating material, 9,10...Filter plate, 11...
...Cylindrical pipe, 12...Nickel foam, 13...
...Metal hydride powder, 20...Cylindrical pressure-resistant container,
40... Filter cylindrical body.

Claims (1)

[Claims] 1 A pressure-resistant container formed in a cylindrical shape with a closed disk at both ends and a hydrogen inlet/output conduit attached to one end of the closed disk, and the closed disk at the cylindrical axis of this pressure-resistant container. A cylindrical heat transfer pipe installed through the pressure vessel, a heat insulating material attached to the inner wall of the pressure vessel, and a heat insulating material provided inside the heat insulating material that allows hydrogen to pass through but not metal hydride powder. A filter cylinder whose entire body is made of a filter is provided between the filter cylinder and the heating medium tube together with a surface-treated foam metal body which is plated with silver or copper after removing the surface oxide film of the nickel foam. A metal hydride container characterized by containing hydride powder.