JPH07269795A - Hydrogen storage alloy holding container - Google Patents

Abstract

PURPOSE:To improve heat efficiency in a holding container, and release stress in the container at the time of thermal expansion and contraction of hydrogen storage alloy by arranging a plurality of divided containers in which a heat medium pipe is arranged, in a hydrogen storage alloy holding container used in a heat pump, a hydrogen storage device, and the like. CONSTITUTION:In a hydrogen storage alloy holding container 1 in which a heat medium leading inlet 8, a heat medium leading outlet 9, and a hydrogen leading-in/leading-out valve 7 are provided, a plurality of divided containers 2 are arranged inside. A heat medium pipe 3 is provided in its meandering shape in each divided container 2, and heat medium pipes 3 in respective divided container 2 are connected to each other in series by a heat medium pipe connecting pipe 5. In each divided container 2, many fins 10 are provided integratedly in the heat medium pipe 3 at intervals of about 1mm vertically so as to facilitate discharging of stored hydrogen, and hydrogen storage alloy (MH) is filled among these fins 10. A filter of about 5mum having heat resistance is provided on the upper part of each divided container 2 so as to prevent splash of the MH.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a hydrogen storage alloy holding container capable of safely storing and releasing hydrogen, which is used for heat pumps, hydrogen storage devices, hydrogen purification devices, actuators and the like using hydrogen storage alloys. is there.

[0002]

2. Description of the Related Art In recent years, hydrogen has been occluded in certain metals or alloys for storage and transportation in the form of metal hydrides, hydrogen separation and purification, heat pumps, heat storage, etc. A method has been proposed. Among alloys that form metal hydrides, alloys that can store and release hydrogen at −20 ° C. to 300 ° C. include LaNi ₅ and CaN.
Typical examples are i ₅ , Mg ₂ Ni and FeTi.
These alloys, called hydrogen storage alloys, are usually used in powder form in order to increase the surface area in order to accelerate the storage and release of hydrogen.

An important point in a system using a hydrogen storage alloy is to increase the hydrogen storage-release rate. In order to increase the hydrogen storage-release rate, an alloy packed bed is used for storing hydrogen. It is necessary to efficiently remove the heat of reaction inside the container to the outside of the hydrogen storage alloy filling container, and to release the hydrogen, to efficiently supply the heat corresponding to the reaction heat from the outside into the alloy packed bed.

Therefore, the container holding the hydrogen storage alloy is
As shown in FIG. 6, an in-container heat transfer medium pipe 13 is provided in the hydrogen storage alloy holding container 1 and the heat transfer medium is flown therein to allow the hydrogen storage alloy 6 to flow.
The exothermic and endothermic heat of is removed, the hydrogenation reaction and dehydrogenation reaction are promoted, and the quick storage and release are performed. Since the hydrogen storage alloy is powder, the filter 11 is provided so that the hydrogen storage alloy does not scatter, and is usually made of a sintered metal having pores of about 2 microns. Also, FIG.
As shown in, the heat transfer medium 4 is placed outside the hydrogen storage alloy holding container 1 to flow a heat medium to remove the heat generated by the hydrogen storage alloy 6 and the heat absorbed by the hydrogen storage alloy, thereby promoting the hydrogenation reaction and dehydrogenation reaction. Then, hydrogen is rapidly absorbed and released through the filter 11.

In the hydrogen storage alloy, the volume of the metal powder expands by about 15 to 30% when hydrogen is absorbed, so that the expansion and contraction of the alloy occurs as the hydrogen is absorbed and released, and the fine powder of the alloy also progresses. It was pointed out that the fine powder is likely to be thickened and a very large stress is applied to the container. From the above, in order to improve the thermal conductivity of the hydrogen storage alloy, prevent pulverization, and alleviate the stress on the container during expansion and contraction of the hydrogen storage alloy, it has been variously used so far. Has been developed.

As a method for improving the heat conduction of the alloy packed bed,
The following methods can be mentioned. (1) A method of improving the container structure in which a large number of heat transfer tubes with fins are arranged vertically and horizontally in the container to increase the contact area with the alloy powder, (2) of a foam metal with high thermal conductivity such as Al. A method of filling the voids with hydrogen-absorbing alloy powder, pressurizing and firing to pelletize it (JP-A-55-126199), adding metal powder such as Cu and Al to the hydrogen-absorbing alloy powder, mixing and compressing. Body or sintered body (Japanese Patent Laid-Open No. 55-90401), and similarly, metal powders such as Cu, Ni, and Al are added to and mixed with the hydrogen storage alloy powder,
C in a state where hydrogen is absorbed in the alloy by activation treatment
A method in which the alloy surface is inactivated (poisoning effect) with O, SO _2, etc., and then press-molded and sintered (JP-A-56-1098).
No. 02), a method of integrally press-molding a heat transfer body, which is a container, and a hydrogen storage alloy powder (JP-A-62-196500).
Japanese Laid-Open Patent Publication No. 2000-242242, etc., a method of improving the thermal conductivity of an alloy powder packed bed by a powder compression molding,

(3) A method for improving heat transfer by stirring and fluidizing the alloy powder from the outside using a shaft that penetrates the container (JP-A-60-60400).
The hydrogen storage alloy powder inside the container was vibrated and fluidized by applying vibration from the outside, which was performed by the present inventors.
There is a method (Japanese Unexamined Patent Publication No. 4-160001) in which heat exchange between the surface of the heat medium tube inside the container and the hydrogen storage alloy powder is significantly promoted.

As a method for preventing pulverization of an alloy, a method of forming a compact by the method (2), a method of adding a third component to the alloy to form an alloy which is difficult to pulverize, or an amorphous hydrogen storage alloy by quenching is used. Metallurgical improvements such as the method of making have been proposed.

As a method for relieving the stress on the container when the alloy expands and contracts, a porous material having elasticity that allows hydrogen gas to pass through but does not allow a hydrogen storage alloy to pass through is installed in the container (JP-A-57-94198). Gazette), a method of fluidizing the alloy of the above (3), and the like have been proposed.

As a method for improving thermal efficiency and maintenance, a method of using a heat insulating material having heat retaining property, air permeability and elasticity (Japanese Patent Publication No. 57-57401), separation of a heat exchanger and a pressure vessel. (Japanese Patent Publication No. 57-23796 and Japanese Patent Publication No. 58-26994), one in which a porous body is installed in a small room partitioned by a partition plate (Actual No. Sho 58-78).
No. 36) is proposed. Install the fin tubes inside one large main body container divided by a shelf,
There is an example of isolation from the container wall (Japanese Patent Publication No. 5-6119).
Issue). When the size is increased, since the inner container 50 is a rectangular parallelepiped, the space usage rate in the main body container is reduced. Further, since a large amount of MH is supported by one inner container, the strength of the inner container is required, and sensible heat is inevitably increased.

[0011]

In order to carry out highly efficient heat transfer using the heat of reaction of MH, it is necessary to speed up the heat transfer to MH and reduce the heat loss during heat exchange.
The heat transfer characteristics of the container and the magnitude of sensible heat of the container are important factors. In addition, as a standard for evaluating the performance of the container including MH, COP (heat output / heat input), heat output (KW / kg)
-MH). In order to increase these values, the container is required to have small sensible heat and excellent heat transfer performance.

In MH, the volume of metal powder expands by about 15 to 20% when hydrogen is absorbed. It is known that the pulverization of the alloy also progresses along with this, so that the MH is easily consolidated in the lower portion of the container and a large stress is applied to the container. In order to effectively recover and utilize the exhaust heat of a steel mill or the like, the amount of the exhaust heat is enormous, so it is more economical to recover a large amount of heat using a large-scale container. In this case, it is expected that large stress will be applied to the lower part of the container.

In order to increase the COP of the container, the shell side of the shell-and-tube type having a large ratio of MH weight / MH container weight is filled with MH, and a fin tube for flowing a heat medium is arranged. In many cases, a container having a high heat transfer area according to the method (1) is used. When the size is increased by this method, tensile stress acts on the container wall due to the expansion pressure of MH. Therefore, from the viewpoint of safety, the height of the MH layer is generally suppressed to 50 cm or less.

Thermal conductivity of an alloy powder packed layer formed by compression molding of a powder, such as a method of filling a hydrogen-absorbing alloy powder into voids of a foam metal having high thermal conductivity such as Al, pressurizing, sintering and pelletizing. In the above method (2) by improving the above, a binder for pelletizing is required, and this amount is 20 to 3
Since it is about 0%, a part of the reaction heat generated is taken by the sensible heat of the binder, so that there is a problem that the thermal efficiency becomes low. In the method of (3), the alloy powder is agitated from the outside using a shaft that penetrates the container to fluidize the alloy powder, thereby improving heat transfer. For this reason, there is a problem that hydrogen leaks inevitably at the portion where the shaft and the container are fitted together.

Further, the present invention provides vibration from the outside to remarkably promote heat exchange.
In the method disclosed in Japanese Patent No. 60001, the hydrogen storage alloy inside the holding container flows by applying vibration from the outside, and violent contact with the heat transfer medium pipe inside the holding container causes the amount of heat held by the hydrogen storage alloy to change. It moves quickly to the medium inside, significantly promoting heat transfer. On the other hand, due to the internal structure of the hydrogen storage alloy holding container, the flow of the hydrogen storage alloy is obstructed, and the heat transfer effect is reduced.

In order to improve thermal efficiency and maintenance, Japanese Patent Publication No. 5-6119 discloses that the heat exchanger and the pressure vessel are separated and the MH packing layer is divided by a partition plate or the like as shown in FIG. Although a container having a structure partitioned into rooms has been proposed, the internal container 12 requires a large amount of weight due to its large size, so that the container itself needs to have a considerable strength, which causes a problem that sensible heat increases due to the increase in weight. .

The present invention provides a hydrogen storage alloy holding container having an internal structure which has improved thermal conductivity, relaxation of stress on the container when the alloy expands and contracts when the size is increased, and improved thermal conductivity of the MH layer. The purpose is to

[0018]

In order to solve these problems, the present invention improves the thermal efficiency inside the holding container by arranging a plurality of split containers having a special structure inside the hydrogen storage alloy holding container. It is characterized by alleviating the stress on the container at the time of expansion and contraction and improving the thermal conductivity of the MH layer.

The gist of the present invention is as follows. In a hydrogen storage alloy holding container having a hydrogen storage alloy that stores or releases hydrogen in the container, and a heat transfer medium tube that recovers reaction heat generated when storing and releasing hydrogen,
A container that holds hydrogen gas and forms an outer shell, a plurality of box-shaped divisional containers obtained by vertically dividing the interior parallel to the longitudinal direction, and a heat medium disposed inside each divisional container. It is characterized in that it is composed of a pipe, and the heat medium pipes are connected in series by a heat medium pipe connecting pipe outside each divided container. In particular, the inner bottom surface of the box-shaped divided container has a corrugated shape with a gap provided between the crests of the wave, and the portion facing the side surface of the container at a distance from the crests of both ends is curved. Characterize. Further, a plurality of fins are provided on the outer surface of the heat transfer medium pipe arranged in the box-shaped divided container.

The present invention will be described in detail below. Figure 1
1 is a side sectional view of the hydrogen storage alloy holding container 1 shown in the present invention, FIG. 2 is a vertical sectional view of the hydrogen storage alloy holding container 1, and FIG. 3 is a perspective view of a split container 1 in the hydrogen storage alloy. FIG. 4 is an internal detailed view of the divided container 2.

The hydrogen storage alloy holding container 1 is a closed container having a hydrogen introduction / extraction valve, and a box-shaped divided container 2 is arranged inside. Further, the hydrogen storage holding container has a heat medium introduction port 8 and a heat medium outlet port 9 of a heat medium for recovering reaction heat at the time of hydrogen storage / release of the hydrogen storage alloy. The heat medium pipe 3 reciprocates inside the divided container 2, and the opening 4 of the heat medium pipe connects the divided containers 2 by the heat medium pipe connecting pipe 5. In order to facilitate the recovery of the reaction heat at the time of absorbing and desorbing hydrogen in the heat transfer medium pipe, fins 31 are arranged outside the heat transfer medium pipe in a direction perpendicular to the pipe axis direction as shown in FIG. Increase the heat transfer area of the storage alloy. Regarding heat transfer between the fins and the heat transfer medium pipe, the one integrated with the heat transfer medium pipe is excellent, but a type in which the fins are caulked to the heat transfer medium pipe may be used. The fin spacing is
0.1 mm-2 mm is desirable. The narrower the fin spacing, the better the heat transfer characteristics, but the heat capacity of the fin also increases, so the fin spacing is selected according to the purpose.

In FIG. 2, by using a plurality of divided containers 2, even when the hydrogen storage alloy holding container 1 is enlarged, the individual containers are not overloaded. For this reason, since the strength of the container can be small, the sensible heat of the container supporting the MH is small and the handling such as maintenance is easy. In the case of one dividing container, FIG.
As shown in (1), since the inner container 12 becomes large in weight due to its large size, the container itself needs to have a considerable strength, which causes a problem that sensible heat increases due to the increase in weight.

As shown in FIG. 4, since the heat transfer medium pipe 3 with fins 10 having a high heat transfer area is installed inside the divided container, the heat transfer characteristics are improved and the heat output is improved. Further, the bottom surface of the divided container has a corrugated shape with a space between the crests of the waves, and the part facing the side surface of the container with a space from the crests at both ends is a curved surface. Escapes to the upper part, and the influence of the expansion force on the divided holding container is reduced. With a normal connecting surface of a right angle, the expansion force of the MH is applied to the roots of the bottom surface and the side surfaces, which causes deformation and separation of the roots. Further, by making the bottom surface of the divided container into a corrugated shape with a gap between the crests of the waves, it is possible to reduce the consolidation of MH in the central portion of the divided container. The wave interval and height depend on the width and depth of the split container, but the width of the split container is 50
When the height is 0 mm and the height is 100 mm, the wave interval is 100 m
m, height is about 20 mm. When the packing density of MH is increased, the height becomes higher and becomes about 30 to 40 mm.

[0024]

EXAMPLES The present invention will be further described below based on examples. In FIG. 1 and FIG. 2, a plurality of split containers 2 are installed in the hydrogen storage alloy holding container 1 and penetrate the hydrogen storage alloy holding container 1 to form a heat medium inlet 8, a heat medium outlet 9, and a hydrogen inlet. A discharge valve 7 is provided. In FIG. 3, the heat medium pipe 3
Reciprocates inside the divided container 2, and the opening 4 of the heat medium pipe connects the divided containers 2 by the heat medium pipe connecting pipe 5. In order to facilitate the occlusion and release of hydrogen, the divided container 2 has a high fin structure in which the fins stacked vertically at a distance of 1 mm on the heat medium pipe penetrate through the heat medium pipe.
The space between these fins is filled with a hydrogen storage alloy 6. In order to prevent the scattering of MH, a heat-resistant filter 11 having a thickness of 5 μm is installed on the upper portion of the divided container 2.

At the time of hydrogen storage, hydrogen is introduced from the hydrogen inlet / outlet port 7 and stored in the hydrogen storage alloy 6 in the split container 2. Reaction heat at that time is removed by the heat medium in the heat medium pipe through the fin 10 and the heat medium pipe 3. The heat medium is introduced from the outside of the hydrogen storage alloy holding container 1 through the heat medium introducing port 8, passes through the plurality of divided containers 2, and is discharged to the outside by the heat medium introducing port 9. A heat medium sequentially flows between the divided containers 2 via a heat medium pipe connecting pipe 5. At the time of hydrogen release, the heat medium also passes through the same path, hydrogen is released from the hydrogen introduction / extraction port 7, and hydrogen is released from the hydrogen storage alloy 6 in the split container 2, and the cold heat at that time is the fin 10 The heat medium in the heat medium tube is taken out through the heat medium tube 3 to the outside. The warm heat during the exothermic reaction and the cold heat during the endothermic reaction are used for heating and cooling. As the heat medium, a stable and safe liquid such as water or oil is used.

By providing a plurality of divided containers 2 inside the hydrogen storage alloy holding container 1, the reaction heat is not transferred to the hydrogen storage alloy holding container 1 and the inside of the hydrogen storage alloy 1 is a plurality of containers. Since it is divided into two parts, the weight of the MH to be held is relatively small, and the sensible heat of the divided container holding the MH is also small.

Also in terms of handling, since it is divided into a plurality of divided containers, it is not necessary to install a heavy container during assembly. In addition, a heat transfer tube with a high heat transfer area is installed inside the divided container, and high heat output can be expected. Regarding the stress received by the split container due to the expansion of MH during hydrogenation, it is possible to disperse the stress to the upper part by forming the bottom and side surfaces of the split container into the shape shown in FIG. 4, and the split container due to the MH expansion pressure. The deformation of is gone. By using the hydrogen storage alloy holding container of the present invention, CO
P and heat output are improved.

For the bottom surface and the side surface of the divided container 2, a container made of Teflon was used. It is desirable that the material has low thermal conductivity. As the filter, a mesh-like or felt-like bag filter made of polyester, heat-resistant nylon, glass fiber or the like can be used.

[0029]

EFFECTS OF THE INVENTION By using a plurality of divided containers, each container does not have an excessive weight even when it is upsized, so that the strength of the container does not have to be small. Therefore, the wall thickness is thin and the sensible heat of the container supporting the MH is small. Becomes smaller, COP increases, and handling such as maintenance becomes easy. Further, the heat output can be improved by installing a heat transfer medium pipe having a high heat transfer area inside by devising the bottom surface and the side surface of the partial division container. From these facts, it is possible to improve the efficiency of a system using a hydrogen storage alloy, such as a hydrogen storage alloy storage device, a hydrogen purification device, and an actuator.

[Brief description of drawings]

FIG. 1 is a side view of a hydrogen storage alloy holding container according to an embodiment of the present invention.

FIG. 2 is a sectional view of a hydrogen storage alloy holding container according to an embodiment of the present invention.

FIG. 3 is an explanatory diagram of a divided container according to an embodiment of the present invention.

FIG. 4 is a sectional view of a divided container according to an embodiment of the present invention.

FIG. 5 is a view showing a conventional hydrogen storage alloy holding container.

FIG. 6 is a cross-sectional view of a container for holding a hydrogen storage alloy in which a conventional heat transfer medium pipe is provided in the container.

FIG. 7 is a cross-sectional view of a container for holding a hydrogen storage alloy in which a conventional heat medium pipe is provided outside the container.

[Explanation of symbols]

 1 Hydrogen Storage Alloy Holding Container 2 Split Container 3 Heat Transfer Pipe 4 Heat Transfer Port 5 Heat Transfer Pipe Connection Pipe 6 Hydrogen Storage Alloy 7 Hydrogen Storage Outlet Valve 8 Heat Transfer Port 9 Heat Transfer Port 10 Fin 11 Filter 12 Internal Container 13 Heat medium pipe inside container 14 Heat medium pipe outside container 15 Heat medium inlet

Claims (3)

[Claims] 1. A hydrogen storage alloy holding container having a hydrogen storage alloy for storing or releasing hydrogen in the container, and a heat transfer medium pipe for recovering reaction heat generated when the hydrogen storage alloy stores and releases hydrogen. In, a container that holds hydrogen gas and forms an outer shell, a plurality of box-shaped divided containers obtained by vertically dividing the inside of the container in parallel with the longitudinal direction, and disposed inside each divided container A hydrogen storage alloy holding container, characterized in that each of the divided containers has a heating medium take-out port and a heating medium introduction port of the divided container connected in series by a heating medium pipe connecting pipe. 2. The inner bottom surface of the box-shaped divided container has a corrugated shape with a space between the crests of the wave, and a portion facing the side surface of the container with a space from the crests of both ends. The hydrogen storage alloy holding container according to claim 1, wherein 3. A plurality of fins are provided on the outer surface of a heat transfer medium pipe arranged in a box-shaped divided container.
Alternatively, the hydrogen storage alloy holding container according to item 2.