JPH0433721B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION (a) Field of Industrial Application The present invention relates to a metal hydride container that takes into consideration mechanical strength during an exothermic reaction due to hydrogen absorption of the metal hydride.

(B) Prior Art When storing heat or storing hydrogen by utilizing the hydrogen absorption and release reactions of metal hydrides, a pressure-resistant container is required because the reaction of metal hydrides proceeds under hydrogen pressure. Furthermore, a heat exchanger is essential for transferring heat accompanying the hydrogenation reaction of metal hydrides. Note that metal hydrides are dehydrogenated to return to their original metals, and in this specification, this case is also referred to as metal hydride.

Taking these points into consideration, conventionally, for example,
As seen in Publication No. 47989, a plurality of cylindrical bodies are arranged on a concentric axis, and the central cylinder is made of a filter material that allows hydrogen gas to pass through but not metal hydrides, forming a hydrogen inlet/outlet conduit, and the outside It has been proposed that a cylindrical body is filled with a metal hydride, and a heat medium for heat exchange is allowed to flow through the cylindrical body outside the cylindrical body.

However, in such a conventional container structure, it has been found that during an exothermic reaction accompanied by hydrogen absorption, the metal hydride-filled container portion may crack due to thermal stress, leading to the container being destroyed.

That is, it is necessary to use a material with good heat conductivity for the interface between the metal hydride filling part where the metal hydride is filled and stored and the heat exchange part, which requires some sacrifice in terms of strength. On the other hand, when metal hydrides release hydrogen, they undergo an endothermic reaction and are cooled, so this does not cause much of a problem, but when a shock is applied during an exothermic reaction due to hydrogen absorption, they react explosively and rapidly generate heat. It has been found that this causes large thermal stress to occur at the interface between the metal hydride filling section and the heat exchange section, causing cracks, which may lead to container failure.

(c) Problems to be Solved by the Invention In view of the above-mentioned points, the present invention aims to provide a metal hydride container that can prevent the container from being destroyed due to heat generated when hydrogen is absorbed by the metal hydride. .

(d) Means for solving the problem Therefore, in the present invention, instead of arranging the heat exchange part through which the heat medium flows outside as in the conventional case, it is arranged inside and the metal hydride filling part is arranged outside. , is characterized in that the inner surface of the boundary surface is formed into an uneven shape, and a hollow portion is provided in the thick portion.

(e) Effect During the exothermic reaction due to hydrogen absorption of metal hydrides, the generated heat is conducted to the heating medium through the interface, but
When a hydrogenation reaction occurs rapidly, the metal hydride side of the interface rapidly rises in temperature due to the heat generated and thermally expands, whereas the heat transfer medium side loses heat and the temperature rises to a large extent. large thermal stress is generated at the interface. Conventionally, metal hydrides were placed on the inside of the interface and a heating medium was placed on the outside, resulting in the interface being unable to withstand the thermal stress and deforming. However, by arranging the heat medium on the inside of the interface and the metal hydride on the outside as in the present invention, thermal stress is dissipated outward, and inward thermal stress is formed on the inner surface of the boundary. It is absorbed by the uneven parts and the hollow part formed inside the thick wall, and can prevent the container from breaking.

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

FIG. 1 is a side sectional view of a metal hydride container according to an embodiment of the present invention, and FIG. 2 is a sectional view taken along line A-A thereof. In these figures, a pressure-resistant container 1 consists of a container main body 11 and a lid 12 that house a metal hydride 2 and a heat transfer fin 3, and whose flanges 11a and 12a are joined with bolts 4 and nuts 5. The interior is kept airtight and pressure resistant. A heat transfer tube 6 is installed to airtightly pass through the main body side end 11b of the pressure vessel 1 and the approximate center of the lid 12 to flow a heat medium, and hydrogen gas is further supplied to and discharged from the lid 12. A hydrogen conduit 8 with a valve 7 is attached.

A heat insulating material 9 that allows hydrogen gas to pass through but not metal hydride powder is placed inside the pressure vessel 1, and inside the heat insulating material 9, a metal hydride 2 and a heat transfer fin 3 are placed.
A heat exchanger tube 6 is arranged. That is, a plurality of heat transfer fins 3 are fixed along the axial direction at equal intervals on the outer peripheral surface of the heat transfer tube 6, and the heat transfer tube 6 and the heat insulating material 9 are partitioned by the plurality of heat transfer fins 3. A metal hydride 2 is distributed and housed between them. In addition, the heat exchanger tube 6, the main body side end surface 11b, and the lid part 12
The space between them is welded to ensure an airtight seal.

As shown in FIG. 2, the inside of the heat transfer tube 6 has an uneven cross section perpendicular to the axial direction. Also,
A plurality of hollow portions 10 are formed along the axial direction in the thick-walled convex portion formed on the inner surface of the heat exchanger tube 6.

With the above configuration, the heat exchange action is performed as follows. That is, during heat storage, the heat of the heat medium flowing inside the heat transfer tube 6 in the direction of the arrow is efficiently transferred to the heat transfer tube 6 by the uneven stripes of the heat transfer tube 6, and further, the metal hydride 2 is transferred from the surface of the heat transfer tube 6 and the surface of the heat transfer fin 3. is efficiently conducted. As a result, the metal hydride 2 undergoes a dehydrogenation reaction, and the released hydrogen gas is stored in a hydrogen cylinder (not shown) from the hydrogen conduit 8 through the heat insulating material 9.

On the other hand, during heat dissipation, the metal hydride 2 absorbs hydrogen and generates heat due to hydrogen gas supplied under pressure from the hydrogen conduit 8 through the insulation material 9, but at this time, for some reason, it reacts explosively and rapidly generates heat. There are cases where

In the conventional structure, the metal hydride was placed inside the cylindrical boundary surface and the heating medium was placed outside, so while the inside of the boundary surface experienced rapid thermal expansion, the thermal expansion on the outside was suppressed by the heating medium. Therefore, there was no place for the thermal expansion force to escape, and there was a risk that large thermal stress would occur and cracks would occur at the interface.

However, in the case of this embodiment, as mentioned above,
Since the heat medium is placed inside the heat transfer tube 6, which is the boundary surface, and the metal hydride 2 is placed outside, the thermal stress generated during thermal expansion is dissipated outward. Moreover, the inside of the heat exchanger tube 6 is formed with an uneven cross section, and
A hollow portion 10 is provided in the thick portion. As a result, inward thermal stress is absorbed by the uneven portion and the hollow portion 10. As a result, even if a rapid hydrogenation reaction occurs in the metal hydride 2, the heat exchanger tube 6 can sufficiently withstand it, and an extremely safe metal hydride container can be obtained. At this time, the uneven portions formed on the inside of the heat transfer tube 6 are also useful for improving the efficiency of heat exchange with the heat medium.

In the above embodiment, the hollow part 10 formed in the thick convex strip on the inner surface of the heat exchanger tube 6 was explained as being continuous in the axial direction, but as shown in the side sectional view of FIG. It may be formed. Alternatively, it goes without saying that the shape can be designed as appropriate, such as forming it into a spherical shape.

Further, in the above embodiment, the outer periphery of the metal hydride 2 was directly covered with the filter-like heat insulating material 9, but a normal heat insulating material 9 was used, and the hydrogen conduit 8
A filter material that allows hydrogen gas to pass through but not metal hydride may be interposed therein, and this hydrogen conduit 8 may be extended to the metal hydride layer by passing through the heat insulating material.

(G) Effects of the Invention As described above, according to the present invention, a heat transfer tube is arranged in the center, a metal hydride is arranged around it, and a heat insulating material is interposed around the outer periphery of the heat exchanger tube, and the tube is housed in a pressure-resistant container. A plurality of thick protrusions are formed along the axial direction on the inner surface of the heat transfer tube that airtightly penetrates the pressure-resistant container, and a plurality of thick protrusions formed on the inner surface of the heat transfer tube are provided with a plurality of thick protrusions along the axial direction. Since multiple hollow sections are provided in the tube, even if rapid heat generation occurs during the hydrogenation reaction of metal hydride, the severe thermal stress is dispersed and absorbed, preventing damage to the heat transfer tube. , an extremely safe metal hydride container can be obtained, which can be used for the development of thermal equipment using metal hydrides such as heat pump devices.

[Brief explanation of drawings]

FIG. 1 is a side sectional view of a metal hydride container according to one embodiment of the present invention, FIG. 2 is a sectional view taken along line A-A, and FIG. FIG. 1...Pressure container, 2...Metal hydride, 3...
Heat transfer fin, 4... Bolt, 5... Nut, 6...
...Heat transfer tube, 7...Valve, 8...Hydrogen conduit, 9...
...Insulating material, 10...Hollow part, 11...Container body part, 12...Lid part, 11a, 12a...Flange part, 11b...Body side end surface.

Claims (1)

[Claims] 1 A metal hydride is stored in a cylindrical pressure-resistant container equipped with a hydrogen conduit for supplying and discharging hydrogen gas from the outside with a heat insulating material interposed, and the axial center of the container is hermetically penetrated to supply heat inside. A heat transfer tube is installed to flow the medium,
A plurality of thick protrusions are formed along the axial direction on the inner surface of the heat exchanger tube, and a hollow portion is provided along the axial direction in the thick protrusion formed on the inner surface of the heat exchanger tube. metal hydride container.