JPS5978902A - Hydrogen supply device - Google Patents

Abstract

PURPOSE:To provide a titled device which can foresee the time necessary for occlusion of hydrogen by packing a metallic hydride consisting of a mixture of an essential component of which the hydrogen dissociation pressure is P1 and an auxiliary component of which P2 is lower than said pressure in a vessel and detecting the change in the hydrogen release pressure from P1 to P2. CONSTITUTION:A metallic hydride mixture consisting of the 1st metallic hydride which dissociates hydrogen at a pressure P1 as an essential component and the 2nd metallic hydride which dissociates hydrogen at the pressure P2 lower than said P1 as an auxiliary component is packed in a vessel 1 which has an opening 2 at one end and is finned 7 for heat transmission purpose on the inside wall. The hydrogen dissociated from said mixture passes the inside of a porous pipe 6 which is provided in the vessel 1 and allows the permeation of hydrogen but prohibits the permeation of metallic hydride. The hydrogen is then fed through the filter 5 provided in the opening 2 and connectors 3, 4 to the outside. A pressure detector 7 is mounted to the vessel 1 to detect the decrease in the pressure in the vessel 1 from P1 to P2. It is foreseen from said decrease that decrease that the hydogen is thoroughly released from the metallic hydride packed in the vessel and that the hydride requires the fresh occlusion of hydrogen. The time requiring the hydrogen occlusion is indicated by an alarm 9 via a controller 8.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a hydrogen supply device, and more specifically, the present invention relates to a hydrogen supply device, in which a metal hydride that stores hydrogen is used as a hydrogen supply source, and almost all hydrogen is released from the metal hydride, and a new metal hydride is generated. The present invention relates to a hydrogen supply device capable of knowing in advance the necessity of storing hydrogen.

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. The use of metal hydrides as storage and supply devices for hydrogen is attracting attention.

Unlike conventional hydrogen supply devices such as hydrogen gas cylinders and hydrogen generators, this kind of hydrogen supply device uses a metal hydride that stores hydrogen as a hydrogen supply source, so it can easily supply hydrogen. However, on the other hand, when the hydrogen storage capacity of the metal hydride filled in the container approaches its limit, as is well known, the equilibrium decomposition pressure of hydrogen drops rapidly, making it impossible to supply hydrogen. Sometimes. Such a phenomenon is fatal, for example, for a hydrogen supply device to an analytical instrument. Also, in some cases, air can diffuse back into the container and contaminate the metal hydride.

The present invention has been made in view of the above, and as hydrogen is supplied, the amount of absorbed hydrogen in the metal hydride filled in the container is close to the limit, so hydrogen is replenished and new hydrogen is added. It is an object of the present invention to provide a hydrogen supply device that can know in advance when hydrogen should be occluded and stored.

The hydrogen supply device of the present invention has a first metal hydride as a main component which dissociates hydrogen at a pressure PI in a container having an opening at one end, and dissociates hydrogen at a pressure P2 lower than P1. after hydrogen has been substantially released from the first metal hydride, hydrogen is released from the second metal hydride. The present invention is characterized in that it is further equipped with means for detecting a pressure change from the pressure P1 to P2.

FIG. 1 shows an embodiment of the hydrogen supply device of the present invention.

The container 1 has an opening 2 at one end, and a normally closed connector 3 is attached to this opening. When in use, the container 1 is connected to another connector 4 on the hydrogen use side to stop the hydrogen from flowing. Form a supply conduit. A pair of males with such functions
Type Ill connectors are already known and commercially available. A filter 5, which allows hydrogen to pass through but not metal hydrides, is attached to the opening of the container in the vicinity of this connector 3. As the metal hydride repeatedly absorbs and desorbs hydrogen, its particle size decreases to a few microns, and when hydrogen is supplied, it flies out of the container.1. Since there is a pestle that can cause this, the filter prevents this. Therefore, the filter desirably has a pore size of 2 microns or less and is formed, for example, from porous sintered metal.

A porous tube 6 that transmits hydrogen but not metal hydrides is attached to the inner end of the opening of the container through the filter, and the other closed end is attached along the tube axis. It extends to or near the bottom of the container and provides an axial hydrogen passage within the container. The other end of the porous tube is fixedly supported on the bottom of the container as required. as needed,
Fins 7 are provided to protrude from the inner wall of the container in order to smoothly and quickly exchange heat with the metal hydride patent container during hydrogen release and storage.

In the present invention, the main component is a first metal hydride that decomposes hydrogen at a pressure P1, and -1
1. Dissolve hydrogen at a pressure P2 lower than P1 %IIl −
1- is filled with a metal hydride mixture having a second metal hydride as a subsidiary component. Strictly speaking, the pressures P1 and P2 are not constant, and as shown in Figure 2, the equilibrium decomposition pressure is particularly high in the region where the hydrogen/metal atomic ratio (H/M) in the metal hydride is large; In a region where this ratio is small, the equilibrium decomposition pressure is low. Therefore, in the present invention, P2 is P
1 means that the pressure P2 at which the second metal hydride releases most of its occluded hydrogen is lower than the pressure P1 at which the first metal hydride releases most of its occluded hydrogen. This means that the difference is small enough, preferably at least a few atmospheres, to be close to the pressure at which the metal hydride has released substantially all of its occluded hydrogen.

In the present invention, preferably, the metal hydride has a hydrogen dissociation equilibrium pressure of 1.1 at a temperature of 20° C. so that both the first and second metal hydrides supply hydrogen at room temperature. One with a pressure of 2 to 10 atmospheres is selected. Therefore, for example, as a metal hydride of ff1l, LaNi
is preferably used. However, it is not limited to these.

The device of the invention requires a hydrogen pressure in the container, in particular from PI to P.
A pressure sensor 7 is provided for detecting the pressure drop to 2. As this pressure sensor, for example, in addition to the pressure gauge of 15', 1. A bellows or a pressure quadrature transducer that converts pressure changes into electrical signals is used. If necessary, a controller 8 is connected to the pressure detector, and when the detected pressure is P2, the controller can activate an appropriate alarm 9. The alarm includes, for example, a buzzer, a lamp, and the like.

Can you give a specific example? 5.31 kg of LaNi in the container
After filling the container with 100 g of LaNi and sufficiently absorbing hydrogen, the container was connected to a gas chromatograph via a connector and a flow rate regulator set at 0.5 kg/crl G, as described above. Connect to the main unit,
While heating the container to a temperature of 40"C, hydrogen was
The hydrogen pressure inside the container was detected using a Bourdon tube pressure 81 at every predetermined supply amount. 3rd result
As shown in the figure. About 1.50 N7! of hydrogen is about 6 kg/c
When released at a constant pressure of JQ, the hydrogen pressure inside the container is approximately 2
．． Although it rapidly decreased to 5 kg / ca G, it is still more than ten N7! During this period, the regulator operated normally and was able to supply hydrogen at a rate of 23 cc/min. In addition, at this point (Y), the pressure inside the container decreased, so it can be known that the amount of hydrogen stored in the container has reached its limit.

Note that, if necessary, the first and second gold-monium hydrides may be used as a mixture of two or more types, and the pressure may be changed in multiple stages as hydrogen is released from the container, and this may be detected. .

As described above, according to the apparatus of the present invention, hydrogen is supplied from the first metal hydride at a substantially constant pressure P1 over a long period of time, but when the hydrogen supply from the first metal hydride ends, In this case, the device can continue to supply hydrogen with the second metal hydride, and the pressure change from Pl to P2 can be clearly detected. can be seen to be close to the limit.

[Brief explanation of the drawing]

FIG. 1 is a cross-sectional view of essential parts showing an embodiment of the hydrogen supply device of the present invention, and FIG. 2 is a sectional view of If in the first and second metal hydrides.
FIG. 3 is a graph showing the relationship between the amount of hydrogen supplied by the apparatus of the present invention and the equilibrium cracking pressure. 1... FIB, 2... Opening, 5... Filter, 6... Porous tube, 7... Pressure detector, 8...
Controller, 9...W alarm. Patent applicant Mototoshi Fujinuma, representative of Sekisui Chemical Co., Ltd.

Claims (1)

[Claims] (1) In a container having an opening at one end, the main component is a first metal hydride that dissociates hydrogen at a pressure P1.
A metal hydride mixture having a second metal hydride as a subcomponent which dissociates hydrogen at a pressure P2 lower than that of A hydrogen supply device characterized in that hydrogen is released from the metal hydride of No. 2 and further comprises means for detecting a change in pressure from the pressure P1 to P2.