JPH0159201B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION (a) Field of Industrial Application The present invention relates to a metal hydride container used in hydrogen storage devices, heat utilization devices, etc. that utilize metal hydrides.

(b) Prior Art It is known that certain alloys (or metals) absorb and release large amounts of hydrogen gas and heat in an activated state by controlling temperature and pressure. The temperature and pressure conditions at that time do not need to be so severe (large values) in the active state. However, to go from an inactive state to such an active state requires quite severe conditions. For example, in the case of FeTi, the reaction can be carried out at a temperature in the range from room temperature to 40°C after activation and at a hydrogen pressure of 10 atm or less. However, the activation of the alloy requires temperatures above 400℃ and hydrogen pressure.
Conditions of 40 atm or more are required.

In addition, the metal (alloy) after activation absorbs hydrogen,
Due to release, the metal (alloy) and metal hydride state will be changed back and forth, but in the following description, all of these states will be referred to as metal hydride to the extent that it does not cause any problem.

Conventionally, in metal hydride containers that house these metal hydrides and perform hydrogen absorption and desorption reactions, it is difficult to take the activated metal hydride in and out of the container without exposing it to air. Activation was also performed in the same container. For this reason, the container structure must be designed to withstand the activation conditions, necessitating the use of large wall thicknesses and expensive materials that are unnecessary for use after activation. In addition, if the metal hydride in the container deteriorates due to impurity gas or other causes and needs to be replaced for regeneration operation, it is not possible to replace just the metal hydride, and an expensive pressure-resistant container is required for replacement. I had to.

Furthermore, in order to change the operating mode of the system,
Even when it was desired to change the type of metal hydride filled in the container, there were problems such as having to replace the container with an expensive pressure-resistant container.

(c) Problems to be Solved by the Invention The present invention solves the above-mentioned problems, makes it possible to make the container structure inexpensive enough to withstand the necessary conditions in a normal activated state, and to improve the container structure. It is an object of the present invention to provide a metal hydride container that can be reused and the metal hydride inside can be freely exchanged.

(d) Means for Solving the Problems For this reason, the present invention provides a hydrogen inlet/outlet conduit having a check valve that opens when the internal pressure becomes higher than the outside pressure inside a sealed pressure vessel equipped with a hydrogen inlet/outlet conduit having an on-off valve. A metal hydride holding container equipped with a conduit and a hydrogen inlet/output pipe having a check valve that opens when the internal pressure is lower than the outside pressure is housed, and the holding container is filled with metal hydride. There is.

(e) Action: A metal hydride holding container equipped with a check valve is filled with an alloy that forms metal hydrides, and the metal hydride holding container is preliminarily heated to withstand the hydrogen pressure and temperature necessary for activation of the alloy at the initial stage of the reaction. Activate the alloy in a separate pressure vessel. After the hydrogen pressure in the pressure vessel and the metal hydride holding vessel is brought to approximately the same level as atmospheric pressure, the metal hydride holding vessel is taken out into the air. At this time, since air does not flow into the metal hydride holding container due to the action of the check valve, the activated metal hydride will not be oxidized or inactivated by air. Next, this container can be stored in a pressure-resistant container that can withstand the hydrogen pressure and temperature required for the hydrogen absorption and release reaction after activation, and the metal hydride in the metal hydride holding container can be stored under relatively mild conditions. can absorb and release hydrogen.

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

FIG. 1 is a block diagram of a metal hydride container according to an embodiment of the present invention, in which FIG. 1A is a sectional view thereof, and FIG. In these figures, the metal hydride container of this embodiment houses a metal hydride holding container 3 filled with a metal hydride 2 in a pressure-resistant container body 1, and also has a container lid 5 with a hydrogen inlet/output conduit 4. It is attached to the upper part of the pressure vessel main body 1 by flange connection and the inside is sealed. The hydrogen inlet/outlet conduit 4 is provided with an on-off valve 6 for letting hydrogen gas in and out of the container.

The metal hydride holding container 3 is provided with check valves 7 and 8, respectively.
It consists of a container to which two hydrogen inlet and outlet conduits 9 and 10 are attached, and the metal hydride 2 is filled inside. The check valve 7 opens when the hydrogen pressure inside the metal hydride holding container 3 becomes higher than the outside, and the check valve 8 opens when the hydrogen pressure inside the metal hydride holding container becomes lower than the outside. is set to For example, spring type check valves can be used as the check valves 7 and 8. In this case, a pressure difference greater than a certain pressure is required to open the check valve, but this pressure difference is
It is best to set it to around 0.5 atm.

This metal hydride holding container 3 is filled with an alloy before activation, such as an FeTi alloy, and then placed in a separate container (not shown) that can withstand the activation conditions of the alloy, and then subjected to activation treatment. That is, the metal hydride holding container 3 is placed in the pressure-resistant container body 1, and the temperature inside the container is maintained.
Keep above 400℃ and hydrogen pressure above 40atm. Then,
Hydrogen gas is taken in and out of the metal hydride holding container 3 through the check valves 7 and 8, so that the conditions are almost the same as in the pressure container. As a result, the metal hydride filled in the metal hydride holding container 3, in this case the FeTi alloy, is activated.

The metal hydride holding container 3 in which the metal hydride 2 has been activated is taken out from the pressure container body 1 after adjusting the internal hydrogen pressure to approximately atmospheric pressure. At this time, the hydrogen inlet/output pipe 9 of the metal hydride holding container 3,
In order to open the check valves 7 and 8 provided in the valve 10, a pressure difference greater than a certain pressure is required. Therefore, even if there are slight pressure fluctuations in the air pressure and the hydrogen pressure inside the metal hydride holding container 3, the inside of the metal hydride holding container 3 can be kept closed. As a result, even if the metal hydride holding container 3 is taken out into the air, the metal hydride 2 will not come into contact with the outside air.
It can remain stable and active.

This metal hydride holding container 3 is connected to the pressure container main body 1.
A lid body 5 equipped with a hydrogen inlet/outlet conduit 4 having an on-off valve 6 is attached by flange joining,
Seal the inside. Next, hydrogen gas is introduced and exhausted from the hydrogen inlet/output pipe 4 to cause the metal hydride 2 to undergo hydrogen absorption and release reactions. At this time, since the metal hydride 2 has already undergone the activation process, it absorbs hydrogen under much gentler conditions than before activation.
A release reaction can take place.

As a result, the pressure-resistant container main body 1 and the lid 5 can be made of materials and structures that can withstand the temperature and pressure conditions under this activation state.
A wide range of materials can be selected, including stainless steel (SUS316 and SUS304), copper, and aluminum, and the container wall thickness can also be significantly reduced. Furthermore, it is possible to employ a relatively simple hermetic structure, such as packing the joint between the pressure-resistant container body 1 and the lid 5 using a material such as Viton, Teflon, or silicone.

At this time, the metal hydride holding container 3 also has a differential pressure.
Since it only needs to withstand about 0.5 atm, it is not necessary to have a pressure-resistant structure, and an extremely simple closed container structure is sufficient.

Therefore, in terms of regulations regarding the manufacture and use of containers,
Since it can be used at a pressure of 10 kg/cm ² or less, it is outside the scope of the High Pressure Gas Control Law, and anyone can easily and safely handle it without being restricted by installation location.

Incidentally, the structure of the metal hydride container of the present invention is not limited to the structure shown in the above embodiments, and various changes can be made without departing from the scope of the claims.

For example, as shown in FIG. 2, a heat medium pipe 11 may be provided inside the metal hydride holding container 3 by airtightly penetrating the metal hydride holding container 3 from the lid 5 of the pressure container. In this case, the metal hydride 2 can be heated and cooled to efficiently promote hydrogen absorption and release reactions.

In addition, as shown in FIG. 3, by disposing a disk-shaped filter 12 on the inner upper surface of the metal hydride 2 that allows hydrogen to pass through but not the metal hydride, the metal hydride of the metal hydride 2 can be retained. Scattering outside the container 3 can be prevented.

In addition, this filter, as shown in Figure 4,
The cylindrical filters 13 and 14 are formed into a cylindrical shape.
may be connected to the hydrogen inlet/output conduits 9 and 10, respectively, and disposed deeply within the internal metal hydride 2 of the metal hydride holding container 3. In this case, it is possible to prevent the metal hydride 2 from scattering, and to make it easier for the metal hydride 2 to come into contact with hydrogen gas, so that the hydrogen absorption and release reactions can be carried out efficiently.

(g) Effects of the invention As explained above, according to the present invention, the following effects can be obtained.

(1) Activation of metal hydrides can be performed in a separate pressure-resistant container, so the pressure-resistant container only needs to withstand the gentle temperature and pressure conditions required for hydrogen absorption and release reactions after activation.As a result, a wide range of containers can be used. It becomes possible to select materials and reduce the container wall thickness, making it possible to manufacture pressure-resistant containers at low cost.

(2) Selection of the metal to be used, such as the ease of using alloys such as FeTi, which had not been used until now because they were difficult to activate despite being excellent in hydrogen absorption and release and available at low cost. The range expands.

(3) In the unlikely event that the metal hydride in the metal hydride container needs to be recycled or replaced due to deterioration, etc., only the metal hydride holding container should be removed and replaced without replacing the pressure container. Can be done. Further, even if the metal hydride holding container is taken out into the air in this way, there is no risk that the metal hydride will come into contact with the air. Therefore, only the metal hydride can be replaced economically and safely, making maintenance extremely simple.

(4) When it becomes necessary to change the type of metal hydride in order to change the operation mode of a heat utilization system using a metal hydride container,
Since there is no need to replace a pressure-resistant container, the replacement work is economical and extremely easy.

[Brief explanation of drawings]

1 to 4 show configuration diagrams of metal hydride containers showing respective embodiments of the present invention, and in each figure, a is a vertical sectional view, and b is a horizontal sectional view. 1...Pressure vessel main body, 2...Metal hydride, 3
...Metal hydride holding container, 4,9,10...Hydrogen inlet/output conduit, 5...Lid, 6...Opening/closing valve, 7,8
... Check valve, 11 ... Heat medium pipe, 12 ... Filter, 13, 14 ... Cylindrical filter.

Claims (1)

[Scope of Claims] 1. A pressure-resistant container having a closed structure inside and equipped with a hydrogen inlet/output conduit having an on-off valve, and a check valve that is housed inside the pressure-resistant container and opens when the internal pressure becomes higher than the outside pressure. a hydrogen inlet/outlet conduit with a check valve that opens when the internal pressure is lower than the outside pressure, and a metal hydride holding container that stores a metal hydride inside and has a sealed structure. A metal hydride container characterized by: 2. A metal hydride container according to claim 1, characterized in that a heat medium pipe is provided inside the metal hydride holding container by airtightly penetrating the metal hydride holding container from the pressure-resistant container. 3. The metal hydride container according to claim 1, characterized in that a filter is disposed inside the metal hydride holding container to allow hydrogen to pass through but not to allow metal hydride to pass through.