JPS6343321B2 - - Google Patents

Description

[Detailed description of the invention] FIELD OF THE INVENTION This invention relates to metal hydride reaction vessels.

It is known that certain metals and alloys exothermically absorb hydrogen to form metal hydrides, and that these metal hydrides reversibly and endothermically release hydrogen. Various metal hydride devices have been proposed, such as heat pumps that utilize the characteristics of metal hydrides.

In such a metal hydride device, metal hydride is filled in a closed reaction vessel to absorb and release hydrogen. Figures 1 and 2 show an example of such a metal hydride reaction vessel, in which a pressure vessel 2 having a hydrogen inlet/outlet 1 at one end is provided with a hydrogen-impermeable partition wall 3 across the vessel adjacent to the hydrogen inlet/outlet. An inner tube 5 having a plurality of fins 4 extending radially from the inner wall is inserted inside this partition wall, and a porous tube 6 that permeates hydrogen but not metal hydrides is used as a hydrogen passage. It is inserted and held in the gap between the tips of the fins, extending in the axial direction of the container with a slight clearance, and is fixed to the partition wall at the end having the opening 7 so that the opening faces the hydrogen inlet/outlet.

The metal hydride is filled in the space between the fins inside the inner tube, and when hydrogen is stored, hydrogen is mainly distributed in the axial direction of the container by the porous tube through its inlet and outlet and the opening of the porous tube. , diffuses into the packed bed of the metal hydride, while during hydrogen release, the hydrogen released from the metal hydride is similarly led from the porous tube through its opening from the hydrogen inlet/outlet of the vessel to another reaction vessel.

Here, the porous tube allows only hydrogen to pass through.
It has a porosity of 40 to 80% and has a filtration performance of several microns, and also has elasticity so that it can absorb the volume change when metal hydride absorbs and releases hydrogen, and relieves stress on the pressure vessel. It is made from synthetic resins such as polyethylene, polypropylene, and polytetrafluoroethylene.

However, with such a reaction vessel, the main problems are that the volume of the metal hydride expands when it absorbs hydrogen, and that the metal hydride is compacted at the hydrogen inlet and outlet sides of the vessel. As a result, as hydrogen storage and release is repeated, the porous tube is crushed at the end of the container on the hydrogen inlet and outlet side, regardless of its elastic restoring force, and ceases to function as a hydrogen passage. Therefore, if the porosity of the porous tube is reduced in order to increase its elasticity, the pressure loss during hydrogen flow will increase. Further, even if the clearance between the porous tube and the tip of the fin is small, the metal hydride may move within the container while the reaction is repeated, becoming unevenly distributed and compacted.

The present invention was made in order to solve the above-mentioned problem, and by forming the cross-sectional shape of the porous tube into an irregular shape without reducing the porosity of the porous tube, it is possible to reduce the stress caused by the expansion of the metal hydride. Endure well;
It is an object of the present invention to provide a metal hydride reaction container that is not crushed even if the metal hydride repeatedly undergoes hydrogen absorption and release reactions.

In the metal hydride reaction container of the present invention, an inner tube equipped with a plurality of fins extending radially from the inner wall is pressed against the inner surface of a tubular pressure-resistant container having a hydrogen inlet/outlet, and hydrogen is introduced into the gap between the tips of the fins. A porous tube that permeates the metal hydride but does not permeate the metal hydride is inserted and fixed, and the wall of the porous tube is curved outward between adjacent fins to have an irregular cross-section, and the inner wall, It is characterized in that the space formed by the fins and the porous tube is filled with a metal hydride.

FIG. 3 shows a cross-sectional view of an embodiment of the metal hydride reactor vessel of the invention corresponding to FIG. 2, in which the same parts as in the previous figure have been given the same reference numerals.

The tubular pressure-resistant container 2 is not particularly limited as long as it can withstand volume changes and hydrogen pressure when metal hydride absorbs and releases hydrogen, and has hydrogen embrittlement resistance.
It is usually made of copper or stainless steel, and, as mentioned above, has a hydrogen inlet/outlet at its front end, a bulkhead extending across the container in proximity to the inlet/outlet, and a plurality of fins 4 extending radially from the inner wall. An inner tube 5 is press-fitted to the inner surface of the pressure tube.
In the present invention, the above-mentioned porous resin tube 6 is inserted into the gap between the tips of the fins as a hydrogen passage, and is fixed to the tips of the fins under pressure, and the tube wall is external between the adjacent fins. in the direction, that is, expands and curves into the gap between the fins,
In this way, the cross section is formed into an irregular shape. Note that the inner tube is manufactured by extrusion molding from a metal material such as aluminum so as to integrally have fins.

In order to make the porous tube have an irregular cross section and fix it under pressure between the tips of a plurality of fins as described above, in addition to forming the porous tube in advance to the irregular cross section shown in FIG. The fins of the inner tube are formed so as to have an extremely small clearance with respect to the inner tube, and a porous tube is inserted into the gap between the tips of these fins.
Next, the inner tube is drawn to reduce its outer diameter. As a result, the tips of the fins press against the wall of the porous tube, and the wall between adjacent fins swells outward and curves. In addition, as described above, a porous tube is inserted and held between the fins, and after this inner tube is inserted into a pressure tube, the pressure tube is drawn and pressed against the inner tube, and at the same time the outer diameter of the inner tube is reduced. Even so, the porous tube can be fixed between the tips of the fins with an irregular cross-section as described above.

Therefore, according to the conventional reaction vessel, the porous tube is simply inserted and fixed into the gap between the tips of the fins, so that all the stress when the metal hydride expands acts perpendicularly to the tube wall. Although a porous tube is easily flattened by a relatively small stress regardless of its elastic restoring force, according to the metal hydride reaction vessel of the present invention, as described above, The porous tube is fixed by pressure in the gap between the tips of the fins, and the porous tube is formed with an irregular cross-section that curves outward between adjacent fins, so that stress caused by volumetric expansion when metal hydride absorbs hydrogen is reduced. is distributed in two directions, one perpendicular to the tube wall and one along the tube wall, and as a result, the stress component perpendicular to the tube wall is reduced, so that the porous tube is not crushed even when the metal hydride volume expands. There is no. Furthermore, since the space between the fins is sealed by the wall of the porous tube, the metal hydride does not move within the container, and therefore does not become unevenly distributed or compacted.

In addition, in the present invention, hydrogen inlets and outlets are provided at both ends of the pressure-resistant container, partition walls are provided in proximity to these inlets and outlets, and an inner pipe is pressed between these partition walls, and a porous pipe is placed between the tips of the fins. may be fixed to each wall with the openings at both ends facing each hydrogen inlet/outlet.

[Brief explanation of drawings]

FIG. 1 is a sectional view showing a conventional metal hydride reaction vessel, FIG. 2 is a sectional view taken along the line - in FIG. FIG. 1... Hydrogen inlet/outlet, 2... Pressure resistant container, 3... Partition wall, 4
...Fin, 5...Inner tube, 6...Porous tube, 7...Opening.

Claims (1)

[Claims] 1. An inner tube equipped with a plurality of fins extending radially from the inner wall is pressed against the inner surface of a tubular heat-resistant container having a hydrogen inlet/outlet, and the space between the tips of the fins is
A porous tube that permeates hydrogen but does not permeate metal hydride is inserted and fixed in the porous tube, and the wall of the porous tube is curved in many directions between adjacent fins to have an irregular cross-sectional shape. A metal hydride reaction vessel characterized in that a space formed by the inner wall, fins, and porous tube is filled with a metal hydride.