JPS6246481B2 - - Google Patents

Description

[Detailed description of the invention] The present invention relates to a method for storing hydrogen.

Hydrogen is widely used in various industrial fields, and there is a need for efficient, safe, and easy storage and transportation of hydrogen. Traditionally, hydrogen has been stored and transported in containers as high-pressure hydrogen gas or liquid hydrogen, but because it requires a large amount of energy to achieve high pressure or ultra-low temperature, recently hydrogen storage alloys have been used. Attempts to use are being actively considered.

Hydrogen storage alloys are alloys that have the ability to store hydrogen _H2.There are various hydrogen storage alloys that are already known, but when they come into contact with pressurized hydrogen, they store hydrogen and become metal hydrides, which generate heat. However, when a metal hydride is depressurized and heated, it releases hydrogen and absorbs heat.
Note that when the hydrogen storage alloy is brought into contact with pressurized hydrogen, it absorbs hydrogen and becomes a metal hydride. Usually, to make a hydrogen storage alloy absorb hydrogen, it is sufficient to contact it with high-pressure hydrogen at room temperature, and to release hydrogen from a metal hydride, a heat medium such as hot water is passed between the metal hydrides.

The methods of storing hydrogen using hydrogen storage alloys that have been studied to date include the following.

In order to bring the hydrogen storage alloy into sufficient contact with hydrogen, it is housed in a porous metal container such as a wire mesh, punched metal, or foamed metal, and a plurality of these porous metal containers are arranged at predetermined intervals in the container. There are many voids within the container, and the space within the container is reduced by the metal enclosure itself. When a hydrogen storage alloy absorbs hydrogen, its volume expands by about 30%, so the container needs to have a porosity of 50 to 40%. Furthermore, since high pressure is required when storing hydrogen, a high-pressure container is used. Furthermore, by repeatedly absorbing and desorbing hydrogen in the hydrogen storage alloy, the bulk hydrogen storage alloy becomes fine powder, and the hydrogen passage holes in the porous metal container become clogged, and the heat generated during storage causes the hydrogen storage alloy to become fine powder. Solidification occurs due to sintering,
This results in a decrease in reaction efficiency.

In view of the above circumstances, the present invention aims to prevent the hydrogen storage alloy from solidifying and to increase the storage speed for practical use by transporting the hydrogen storage alloy into a container using hydrogen H as a carrier gas. , the hydrogen storage alloy is brought into contact with hydrogen in the pipe to complete the hydrogen storage reaction.

Hereinafter, the present invention will be described in detail based on embodiments shown in the accompanying drawings.

In FIG. 1, the lower part of the high-position tank 1 and the upper part of the low-position tank 2 are connected through a valve 3, and the upper part of the high-position tank 1 and the lower part of the low-position tank 2 are connected through a valve 4. The upper part of the high position tank 1 is connected to the compressor 6 through the filter 5.
, the upper part of the low-position tank 2 and the compressor 6
are connected to each other by piping. Compressor 6
Hydrogen is circulated and pumped through the low-position tank 2, valve 4, high-position tank 1, and filter 5, but if a certain hydrogen storage alloy is selected, the pressure in the high-position tank 1 will be 7 to 8 kg/cm. ^2. With the low tank 2, the weight can be reduced to about 9 to 10 kg/cm ² .

Close valve 3 and open valve 4 Hydrogen storage alloy A
When hydrogen is fed into the low-position tank 2 containing the hydrogen storage alloy A, this hydrogen pressure-feeds the hydrogen storage alloy A and moves it to the high-position tank 1 via the valve 4. Hydrogen storage alloy A
comes into contact with hydrogen during movement, absorbs hydrogen, and becomes a metal hydride. At this time, the hydrogen storage reaction can be accelerated by actively removing the heat generated during the hydrogen storage reaction by passing cooling water through a cooling device such as a spiral tube placed around the outer periphery of the pipe. The hydrogen that has transported the hydrogen storage alloy A to the high-position tank 1 returns to the compressor 6 via the filter 5.

Next, close valve 4, open valve 3, and drop hydrogen storage alloy A. When hydrogen is brought in, the hydrogen flows through low position tank 2, valve 3, high position tank 1, and filter 5, and hydrogen storage alloy A falls. When moving, it comes into contact with hydrogen and absorbs it.

When the above valve operation is repeated, hydrogen storage alloy A
are low position tank 2, valve 4, high position tank 1,
It circulates between valves 3.

Figure 2 shows an example using a cyclone 7, in which the lower part of the cyclone 7 and the upper part of the container 8 are connected via a valve 9, and the lower part of the container 8 is connected to the compressor 6 via a rotary valve or ejector 10. The upper part of the cyclone 7 is connected to the compressor 6, and the upper part of the cyclone 7 is connected to the rotary valve or ejector 10, respectively. The pressure of the circulating hydrogen compressed by the compressor 6 is 7 to 8 kg/cm 2 in the cyclone 7 and 9 to 10 kg/cm ² in the rotary valve or ejector 10 if a certain hydrogen storage alloy is selected.
It is about ^cm2 .

Here, when hydrogen is pumped by the compressor 6 with the valve 9 closed, the hydrogen storage alloy A in the container 8 moves to the upper side of the cyclone 7 via the rotary valve or the ejector 10, and while being moved by this hydrogen. Hydrogen storage alloy A stores hydrogen and becomes a metal hydride, which leads to cyclone 7. The hydrogen that has transported the hydrogen storage alloy A to the cyclone 7 returns to the compressor 6 from the top of the cyclone 7, and the hydrogen storage alloy A remains at the bottom of the cyclone 7.

Next, when the valve 9 is opened, the hydrogen storage alloy A falls and is accommodated in the container 8. Thereafter, when the valve 9 is closed and hydrogen is pumped, the hydrogen storage alloy A is produced as described above.
moves. The hydrogen storage alloy A circulates between the container 8, the rotary valve or ejector 10, the cyclone 7, and the valve 9. After the hydrogen storage is completed, the container 8 can be removed from the piping system and used for distribution.

FIG. 3 is the same as FIG. 2 in that the cyclone 7 is used, but the difference is that a moving container 11 is used. That is, the rotary valve or ejector 10 is connected to the lower part of the stationary container 12 containing the hydrogen storage alloy A, and the movable container 11 is positioned below the valve 9.

Here, when hydrogen is pumped, the hydrogen storage alloy A moves to the cyclone 7 in exactly the same way as in the case of FIG. The hydrogen remains at the bottom of the cyclone 7 and returns to the compressor 6. The metal hydride can be transported by opening the valve 9 and storing the metal hydride in the transfer container 11.

As described above, the present invention transports a hydrogen storage alloy into a container using hydrogen H as a carrier gas, and brings hydrogen into contact with the hydrogen storage alloy in a pipe to complete the hydrogen storage reaction. The present invention is a method for storing hydrogen that has been absorbed, and can be used practically by preventing solidification of the hydrogen storage alloy, increasing the contact area with hydrogen, accelerating the storage rate, and shortening the time required for storage. In this way, since hydrogen is stored during the movement of the hydrogen storage alloy, there is no need to provide a porous metal storage body or the like within the container, and the structure of the container is extremely simplified and mass production is facilitated.

[Brief explanation of the drawing]

The drawings show examples of the present invention. Figures 1, 2, and 3 are system diagrams for storing hydrogen by circulating hydrogen and moving a hydrogen storage alloy. Figures 2 and 3 are system diagrams that use a cyclone. As an example, FIG. 3 shows an example in which a moving container is further used. A...Hydrogen storage alloy.

Claims (1)

[Claims] 1. A hydrogen storage alloy characterized in that the hydrogen storage alloy is transported into a container using hydrogen H ₂ as a carrier gas, and hydrogen is brought into contact with the hydrogen storage alloy in a pipe to complete the hydrogen storage reaction. storage method.