JPS597498B2 - Method of reaction between powder and gaseous body and apparatus for its implementation - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention provides that when a reactive gas is introduced into a reactive powder filled in a reaction container and caused to react, the powder is compressed to three-dimensionally contract, A combination of powder and gas, characterized by inserting an elastic structure that restores its original state when the compression is released, and causing the structure to absorb the volumetric expansion pressure of the powder caused by the reaction between the gas and the powder. This invention relates to a reaction method and an apparatus for carrying out the reaction.

Conventionally, as a method for storing thermal energy, a method has been proposed in which thermal energy is stored in a solid compound in the form of lattice energy by utilizing a highly reversible thermal decomposition reaction of a solid.

For example, examples of such thermal decomposition reaction systems for solid compounds include the following.

(Metal hydride = metal + hydrogen gas (2) Metal carbonate = metal oxide + carbon dioxide gas (3) Metal hydroxide
2 Metal oxide + water vapor (4) Ammonia complex salt Solid salt + ammonia And in order to recover the thermal energy stored in the solid thus produced, the solid is reacted with a cracked gas. , the above reaction is carried out in the reverse direction.

That is, the reaction between the solid and the pyrolysis gas is an exothermic reaction, and by bringing the solid into indirect contact with the heat medium, the generated heat can be stored in the heat medium.

Among the solid compounds mentioned above, metal hydrides have very high hydrogen density, so they are used not only as a means of heat storage.
In recent years, much research has focused on the application of metal hydrides, as they are extremely effective as a means of hydrogen storage.

By the way, in order to carry out the above-mentioned reaction in the opposite direction, the powder is filled in a sealed container, a gas body (decomposed gas) is introduced into the container, and the reaction is caused.

In this case, the solid filled in the container expands in volume as the reaction with the gas progresses.

If this reaction is carried out by tightly packing powder in a reaction vessel,
The internal pressure of the container reaches hundreds of atmospheres, and the container is destroyed by this internal pressure.

Therefore, conventionally, in order to avoid such inconvenience,
It was necessary to keep the powder filling rate in the container low, and to use a horizontal container to carry out the reaction so as not to apply high pressure to the inner wall of the container.

However, such a reaction method inevitably requires a large reaction vessel, and the effective thermal conductivity of the powder-filled bed deteriorates, resulting in disadvantages such as a decrease in reaction rate.

The present invention was made to solve the above-mentioned problems, and involves inserting an elastic structure into the powder filled in a container, which contracts three-dimensionally when compressed and restores itself when the compression is released. , so that the powder is pressed against the inner wall surface of the container, that is,
Powder is tightly packed into the space inside the container in which the elastic structure is inserted, and the required gas is introduced into the tightly packed powder to cause a reaction, and the volume of the powder generated by the reaction is It is characterized by allowing the structure to absorb expansion pressure.

The elastic structure used in the present invention contracts when compressed and returns to its original shape when the compression is released, and can have any shape and structure as long as it has such a function.

For example, the cross section is square, rectangular, circular, oval, star-shaped,
Examples include cylindrical hollow bodies such as.

These hollow structures can be manufactured using flat plates or corrugated plates made of metal or heat-resistant resin.

Further, when the reaction temperature is low, for example, about 200° C. or lower, a plastic foam (styrene foam, polyurethane foam, etc.) or sponge can also be used.

Furthermore, the above-described structure can be provided with a support in order to arrange it in the center of the container.

FIG. 1 shows specific examples of these elastic structures.

Figure 1 a shows two metal thin plates 4 and two metal plates 5, 5.
The cylindrical body 1 with a rectangular cross section, shown in FIG.
is a metal curved plate 2 whose middle part is arcuate and both ends are corrugated.
2A and 2B are perspective views of a cylindrical body 3 formed by welding both ends of the cylinder.

Further, plate a shown in FIGS. 1a and 1b represents a support for placing each cylinder at the center of the container.

In FIG. 2, a cylindrical body 12 made of a corrugated plate is attached to the reaction tube 11 with four
Powder A is inserted and fixed through two supports a, and powder A is inserted into the cylinder 12.
1 is a perspective view of a powder-filled reaction tube 10 formed by filling a space formed between the outer surface of the powder and the inner surface of the reaction tube 11.

In the powder-filled reaction tube 10 formed in this manner, the space b in the central cylindrical portion is unfilled, but all other spaces in the reaction tube are tightly filled with powder, especially powder. It is characterized in that the body A is in contact with the entire inner surface of the reaction tube 11.

Since the conventional powder-filled reaction tube 20 does not have the cylindrical body 11 inside, the corresponding space b needs to be formed in the upper space of the reaction tube 11 as shown in FIG. The inner surface of the upper tube 11 cannot directly contact the powder.

Therefore, even if the reaction is carried out under such conditions, the reaction tube 11
Smooth heat transfer between the powder A and the powder A is not achieved, and the reaction efficiency of this powder-filled reaction tube 20 is inferior to that of the powder-filled reaction tube 10 according to the present invention.

Further, the conventional powder-filled reaction tube 20 cannot be used vertically because it is necessary to form the space b in the upper part of the reaction tube in the longitudinal direction. Since the portion b is fixed as the internal space of the cylindrical body 12, it can be applied to either a horizontal type or a vertical type.

The reactive powder used in the present invention is a solid substance formed by an endothermic thermal decomposition reaction of a solid compound that releases decomposition gas such as a metal, metal oxide, or solid salt, and is a solid substance that is reactive to this. The reactive gas to be released is a cracked gas released by thermal decomposition of a solid compound.

Examples of such combinations of reactive powder and gas include metal/hydrogen gas, metal oxide/carbon dioxide, metal oxide/steam, and solid salt/ammonia.

In the method of the present invention, when a reaction vessel is filled with powder as shown and a gas is brought into contact with the powder to carry out a reaction, the above-described elastic structure is disposed in the powder. .

When the reaction is carried out in this way, as mentioned above, the powder packed bed and the inner wall of the reaction vessel are in close contact with each other over the entire container wall, so the heat generated by the reaction is transferred from the powder packed bed to the container wall. It is efficiently communicated.

By bringing the outer surface of the container wall into contact with a low-temperature heat medium and causing the heat medium to quickly absorb the reaction heat, an efficient reaction between the powder and the gas can be achieved.

Moreover, in this case, the volumetric expansion of the powder that occurs as the reaction between the powder and the gas proceeds is offset by the contraction of the elastic structure, so that the container is prevented from breaking.

Therefore, in the case of the present invention, there is no need to take into account the pressure increase due to the volumetric expansion of the powder, so the thickness of the container wall can be determined depending on the gas pressure.

The volume of the elastic structure used in the present invention is determined depending on the internal volume of the container or the volume of the powder to be filled, and when the powder and gas completely react, the space in the structure closes. It only needs to have a volume that can be stored away.

Generally, the volume of the structure may be in a ratio of 5 to 20 inches, usually about 5 to 15 inches, to the internal volume of the reaction vessel.

Further, it is preferable that the structure is disposed along the longitudinal direction of the container and exists over the entire longitudinal cross section of the container.

Of course, depending on the shape of the container, the structure can be present only in the center.

In the present invention, when a hollow body is used as the structure, pores are provided in the peripheral wall surface forming the hollow body to form a filter, and the gas can be introduced into the powder through the pores, and Conversely, it is also possible to extract the gas introduced into the powder through the pores.

Furthermore, in order to improve heat conductivity, a metallic filler having a particle size coarser than that of the powder may be present in the powder.

In addition, the apparatus used in the present invention is not only used to react the powder and the gas as described above, but also to heat the powder that has reacted and absorbed the gas after reacting the powder and the gas. It can be used as a device for a pyrolysis reaction that decomposes and releases decomposition gas from the powder.

In this case, the volume of the powder decreases as the decomposed gas is generated, but the elastic structure disposed inside the powder expands according to the volume reduction of the powder due to its elastic restoring force.

In this way, the space formed between the outer surface of the structure and the inner surface of the container is always kept tightly packed with powder.

Next, the present invention will be explained in more detail with reference to Examples.

Example A metal hydrogenation reaction was carried out using a reaction tube having the structure shown in FIG.

In this case, the reaction tube 11 has an inner diameter of 2 Crn and a length of 5 Crn.
A stainless steel reaction tube (inner volume: 157 cd) with a wall thickness of 1 m and sealable at both ends with an accumulator was used.

The structure 12 inserted into this reaction tube is made of a phosphor bronze corrugated plate with a thickness of 0.1 mm and has an inner diameter of 0.
．． 62Crn, length 50Crrl cylinder (total volume = 16.
1cd), and a stainless steel metal plate was used as the support plate a for supporting this cylinder.

As the metal powder A, LaNi5, which is known as a hydrogen storage alloy, was used.

Note that the volumetric expansion rate (
LaNi5H6/LaNi5) is 1.255
It is.

This metal powder A (particle size approximately 0.14rrvn) was
As shown in FIG. 2, the space formed between the outer surface of the cylindrical body 11 inserted therein and the inner surface of the tube was tightly filled, and both ends of the reaction tube were sealed with an accumulator.

Next, hydrogen was introduced at a pressure of 10~/cd through a hydrogen introduction pipe provided in one of the storage bodies to perform a hydrogenation reaction of the metal powder.

As this reaction progressed, the surface of the reaction tube was heated by the reaction heat and became hot, and the reaction tube surface temperature rose to approximately 60°C.

After the reaction, one storage body was removed and the shrinkage of the cylinder 11 placed inside the reaction tube was observed, and it was found that the cylinder 11 had clearly contracted, and its cross-sectional area was approximately 10 minutes smaller than the initial size. It was number 1.

[Brief explanation of the drawing]

1A to 1E are perspective views showing the shape of the elastic structure used in the present invention, FIG. 2 is a structural explanatory diagram showing the structure of the device of the present invention, and FIG. 3 is a structure of the conventional device FIG. 1, 2, 3, 12... elastic structure, 11...
...Reaction tube, a...Support plate, b...
Space part, A...Powder.

Claims (1)

[Scope of Claims] 1. When a reactive gas is introduced into reactive powder filled in a reaction container and the two are reacted, the powder contracts three-dimensionally due to compression. A method for reacting powder and gas, which comprises inserting an elastic structure that restores its original shape upon release, and causing the structure to absorb volumetric expansion pressure of the powder caused by the reaction between the gas and the powder. 2. The method according to claim 1, wherein the elastic structure is a hollow body. 3. The method according to claim 1 or 2, wherein the powder is metal and the gaseous body is hydrogen. 4 An elastic structure that contracts three-dimensionally when compressed and restores itself when the compression is released is inserted into a sealed container, and a space formed between the outer surface of the elastic structure and the inner surface of the container is An apparatus for carrying out a reaction between the powder and the gas, the container being tightly packed with a reactive gas and having a reactive gas inlet tube arranged in the container. 5. The device according to claim 4, wherein the elastic body is a hollow body.