JPH0794935B2 - Method for absorbing and releasing hydrogen gas by hydrogen storage alloy and hydrogen storage alloy container - Google Patents

Description

TECHNICAL FIELD The present invention relates to a method for absorbing and releasing hydrogen gas using a hydrogen storage alloy, and relates to a heat pump, a device utilizing movement of hydrogen gas (for example, hydrogen gas turbine), hydrogen gas storage, The present invention relates to the same direction and container that can be advantageously applied to energy conversion, hydrogen separation and purification, and the like.

[Conventional technology]

In the conventional technology, hydrogen gas goes out of the container due to pulverization due to expansion and contraction during hydrogen gas absorption and desorption of the hydrogen storage alloy.
Therefore, the filter prevents the alloy from flowing out.
Further, the hydrogen storage alloy is generally an intermetallic compound and has a small thermal conductivity. For this reason, in order to increase the reaction rate, the alloy layer thickness is made smaller or mixed with a material with high thermal conductivity, but the indirect / heating / cooling system is used.

Fig. 3 shows one embodiment of the conventional method. Hydrogen storage alloy powder 10
The solvent pipe 11 is placed in the containers (A) and (B) filled with
Since it is an indirect / heating / cooling system through piping, the reaction heat transfer speed is slow and one cycle of hydrogen gas absorption / discharge is long.
It should be noted that other pipes, turbines and other systems in FIG. 3 are the same as those of the present invention which will be described in detail later, and therefore description thereof will be omitted. However,
In the figure, 9 is a filter.

[Problems to be solved by the invention]

The above conventional method has a problem that (1) the pulverized hydrogen storage alloy flows out of the container to a large extent, and (2) the indirect heating / cooling method causes a large heat transfer resistance.

The present invention is intended to provide a method for absorbing and releasing hydrogen gas using a hydrogen storage alloy and a container capable of solving the problems of the above conventional methods.

[Means for solving problems]

The present invention encapsulates an activated hydrogen storage alloy with a porous good heat conductive metal and then compresses and molds the capsule powder into a lump to fill a liquid that does not react with the hydrogen storage alloy. Hydrogen storage characterized by introducing hydrogen as a heat transfer medium and heating / cooling it in contact with a direct-encapsulated hydrogen storage alloy to cause the hydrogen storage alloy to store or release hydrogen gas, respectively. This is a method of absorbing and releasing hydrogen gas using an alloy.

Furthermore, the present invention relates to a container used in the above method, which comprises an activated hydrogen storage alloy, a porous capsule made of a good heat conductive metal containing the hydrogen storage alloy, and a container body having a plurality of the capsules. And a hydrogen storage metal alloy container, characterized in that it is provided with a liquid heat transfer medium supply / discharge pipe for immersing the capsule in the container body.

In the above description, the liquid heat transfer medium refers to a liquid that causes heat transfer regardless of whether it is a cooling medium for cooling or a heat factor for heating, and is preferably an organic solvent such as undecane or paraffin. In addition, the capsule may be a coating described below or a small container.

[Action]

Hydrogen storage alloy is contained in a porous capsule,
Because it is breathable, hydrogen itself can enter and leave the capsule, but hydrogen storage alloys cannot enter and exit.

A liquid heat transfer medium such as an organic solvent is supplied to and discharged from the container to promote heat transfer between the capsules.

〔Example〕

The following is a brief description of the novel points of the present invention.

(1) A high thermal conductivity material such as copper having a porous hole that allows hydrogen gas to pass through the hydrogen storage alloy powder that has been activated to prevent outflow of the finely divided hydrogen storage alloy, such as plating. Encapsulation is performed by coating with a means. After that, these powders are compression-molded into lumps.

(2) The indirect heating / cooling method is stopped and a direct heating / cooling method is used in which a liquid heat transfer medium that does not react with the hydrogen storage alloy is brought into direct contact with the encapsulated hydrogen storage alloy as a heat transfer substance.

The above (1) prevents the outflow of the hydrogen storage alloy fine powder, and (2) accelerates the hydrogen gas absorption / desorption reaction of the hydrogen storage alloy, and makes the container simpler than the indirect heating / cooling system.

An embodiment of the present invention will be described below with reference to FIG.
The two containers 2 shown in (A) and (B) may have any shape, but for example, as shown in FIG. 2 (top view is top view, bottom view is side view), an encapsulated hydrogen storage alloy block (here Then, a Cu encapsulation product of LaNi ₅ ) 1 is filled, and a liquid heat transfer medium pipe 6 is provided in the container 2 shown in FIG.
A solvent (here, paraffin) is introduced through. The paraffin heat-exchanged by the heating system 7 and heated to a high temperature (temperature 120 ° C., pressure 20ata) is introduced into the container (A) through the three-way valve 3 and the liquid heat transfer medium pipe 6. Due to the heat of the introduced solvent, hydrogen gas (temperature 10
0 ° C, gas pressure 20ata) is released and guided to the hydrogen gas expansion turbine 4 through the gas pipe 12 to generate electricity and recover electrical energy.

The hydrogen gas (gas pressure 3ata) that has exited the expansion turbine 4 is guided to the container (B) and stored in the encapsulated hydrogen storage alloy 1 in the container (B). The heat generated at this time is cooled to a low temperature (temperature 20 ° C., pressure 4ata) in the cooling system 8, is absorbed by the liquid heat transfer medium 6 through the three-way valve 3 into the direct paraffin supplied by the pump 13, and is cooled. Cooled in system 8. In the figure, 5 is a gas-liquid separator.

By cyclically operating the above system, hydrogen gas can be continuously moved and the generator can be driven.

Two or more of the above containers may be combined to improve continuity.

〔The invention's effect〕

In the conventional method as shown in FIG. 3, indirect heating, cooling, and extra pipes are required in the containers (A) and (B), and the hydrogen storage alloy fine powder is accompanied by the release of hydrogen gas. It required a filter 9 to prevent outflow.

According to the present invention, the above-mentioned necessary parts are unnecessary, and since the liquid heat transfer medium and the hydrogen storage alloy are of the direct heat exchange type, the hydrogen gas absorption / desorption cycle can be shortened to about half that of the conventional method.
(In other words, it means that the amount of high-cost alloy can be halved with the same performance per unit time.)

[Brief description of drawings]

FIG. 1 is a diagram showing a flow of one embodiment of the method of the present invention, and FIG.
FIG. 3 is a schematic diagram of a molding example of an encapsulated hydrogen storage alloy, and FIG. 3 is a flow chart of an example of a conventional method.

Claims (2)

[Claims] 1. An activated hydrogen storage alloy is encapsulated with a porous metal having a good thermal conductivity, and the capsule powder is compression-molded to form a lump, which is then reacted with the hydrogen storage alloy. By introducing a liquid that does not exist as a heat transfer medium and directly contacting the encapsulated hydrogen storage alloy with heating and cooling, the hydrogen storage alloy is allowed to store hydrogen gas or release hydrogen gas, respectively. A method for absorbing and releasing hydrogen gas using a hydrogen storage alloy. 2. A porous capsule made of an activated hydrogen storage alloy and a metal having good thermal conductivity which contains the hydrogen storage alloy, a container body having a plurality of the capsules, and the capsule in the container body. Supply of liquid heat transfer medium to immerse,
A hydrogen storage alloy container comprising a discharge pipe.