JPS5953203B2 - Hydrogen gas storage and purification equipment - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a hydrogen gas storage and purification device using a hydrogen storage alloy, such as a titanium-manganese alloy.

Hydrogen gas is important as an industrial raw material and auxiliary material, and is used in large quantities in many fields, such as in the synthesis of ammonia and methanol, and in petroleum refining.

The production of hydrogen gas, which plays an important role in modern industry, is mainly carried out by electrolysis of water, decomposition of ammonia, decomposition of hydrocarbons (natural gas and petroleum), decomposition of methanol, etc.

Hydrogen gas produced by this method generally contains impurities such as inert rare gases such as helium, krypton, and argon, and inorganic gases such as oxygen, nitrogen, carbon monoxide, carbon dioxide, ammonia, and water. Contains.

Therefore, hydrogen storage methods and crude hydrogen gas purification are required depending on the intended use.

There are various methods for purifying crude hydrogen gas, but the method using a hydrogen storage alloy is considered promising because it is easy to operate and can be used repeatedly.

That is, this method takes advantage of the fact that the alloy that stores hydrogen stores only hydrogen in the hydrogen gas containing impurities, and the hydrogen gas that is released from this has a higher purity than the hydrogen gas when it is stored.

Here, when hydrogen gas is stored as an alloy hydride and the stored hydrogen is released and used, the purity of hydrogen improves, so the hydrogen storage device and the purification device are ultimately the same mechanism. Therefore, the following explanation will focus on the purification equipment.

In hydrogen gas purification equipment using this type of hydrogen storage alloy, when hydrogen is stored, it generates heat, and when hydrogen is released, it is stored, so when releasing hydrogen, it is heated by an external heat source, and then the hydrogen is stored. On the other hand, if an external heat source is not used, the alloy temperature will drop and the flow rate will decrease because sufficient heat exchange with the ambient temperature will not be possible. It has drawbacks such as the amount of hydrogen being reduced and furthermore, it takes a long time to utilize all the stored hydrogen.

The present invention aims to eliminate these drawbacks, and focuses on the properties of hydrogen storage alloys, such as the amount of heat generated when storing hydrogen and the amount of heat absorbed when releasing hydrogen. This accumulated heat is used to store and release hydrogen intermittently or continuously.

That is, the present invention uses at least one set of hydrogen purification vessels containing hydrogen storage alloys that are connected to each other through heat storage containers so as to be able to exchange heat, and the amount of heat generated during hydrogen storage is once stored in the heat storage containers. The hydrogen stored in the alloy is stored in the alloy, and the hydrogen stored in the alloy is released as purified hydrogen from the same container or another container using the heat amount.

According to the present invention, the heat of hydrogen storage in one container can be used indirectly to release hydrogen from the same container or the other container as needed, so there is no time lag between the storage and release of hydrogen. High-purity hydrogen gas can also be extracted almost continuously by alternately supplying hydrogen to be purified to a container containing a hydrogen storage alloy.

Hereinafter, the present invention will be explained with reference to examples thereof.

In FIG. 1, reference numeral 1 denotes a hydrogen storage container (high-pressure cylinder) filled with industrial compressed hydrogen, and a hydrogen supply pipe 3 is connected to the opening of the container via a stopcock 2.

The pipe 3 is equipped with a primary gauge 4, a secondary gauge 5, and a valve 6, and its tip is connected to hydrogen purification vessels 7, 7' having gas passages connected in parallel.

The containers 7, 7' each contain a hydrogen storage alloy 8.8', and are provided with filters 9, 9' and 10.10' on their hydrogen gas inlet and outlet sides.

Reference numerals 11 and 11' indicate valves provided on the hydrogen gas inlet side of the container 7°7', and 12 and 12' indicate valves provided on the outlet side.

The tube 13 connected to the valve 12.12' has the valve 1
A vacuum pump 16 is connected to the upstream side of 4 via a valve 15.

17 and 17' are heat exchangers built into the containers 7 and 7', and are interconnected by pipes 18.

Reference numeral 19 denotes a heat storage container containing a heat medium 20, which is surrounded by a heat insulating material so that heat can be accumulated therein.

Inside this heat storage vessel 19 there is a heat exchanger 21, which is connected to the pipe 18 by a three-way valve 22, 22' and a pump 2
3 allows the heat medium to circulate.

The container 19 is also provided with a liquid filling stopper 24 .

Note that water, ethylene glycol, or a mixture thereof is preferable as the heat medium.

In addition, the filters in the containers 7 and 7' have a pore size of 0.1 to several μm.
It is preferable to use a metal sintered body having a diameter of about 100 m.

Next, a method of operating this device will be explained.

First, after replacing the inside of the tube 3 with hydrogen gas, the vacuum pump 16
is operated to suction and remove the air in the containers 7, 7' and the pipes, and then the valves 12, 12' and 15 are closed, and the valves 11, 11' and 14 are also closed.

When the stopcock 2 of the hydrogen storage container 1 is opened, the primary pressure of hydrogen is displayed on the primary gauge 4.

Next, the secondary pressure is adjusted using the valve 6.

When the valve 11 is opened in this state, hydrogen gas passes through the filter 9 in the container 7 and is stored in the hydrogen storage alloy 8.

The heat generated during hydrogen storage is accumulated in the heat storage container 19.

That is, by operating the three-way cocks 22 and 21' to connect the heat exchangers 17 and 21 and driving the pump 23 to circulate the heat medium, the heat generated by hydrogen storage in the container 7 is transferred to the heat storage container 19. It is accumulated in the heat medium 20 inside.

In addition, if the valve 11 is closed and the valve 11' is opened and hydrogen is stored in the hydrogen storage alloy 8' in the other container 7' through the filter 9', the heat generated in this storage process is transferred to the heat exchanger 17'. By circulating a heat medium between 21 and 21,
It can be stored in a heat storage container 19.

After the hydrogen storage process is completed in this way, the valve 11
' is closed and the valves 12 and 14 are opened when necessary, the hydrogen gas stored in the alloy 8 is released into the pipe 13 through the filter 10 in the container 7.

At this time, by circulating a heat medium through the heat exchangers 17 and 21, the hydrogen storage alloy 8 is heated with the heat stored in the heat storage container 19, so that hydrogen is released more efficiently. be able to.

Similarly, when hydrogen is stored in the container 7 or 7', heat is stored in the heat storage container 19', and hydrogen can be released from the hydrogen storage alloy in the container 7' using that amount of heat.

As described above, one or more containers containing a hydrogen storage alloy are connected via a heat storage container and a heat medium path, and hydrogen gas is stored and released alternately, so that one container can store and release hydrogen gas. Purified hydrogen gas can be efficiently extracted by using heat to release hydrogen gas from the same container or the other container.

In the device of FIG. 2, a heat exchanger 21' in a heat storage container 19
, 21'' and the heat exchangers 17 and 17' of the containers 7 and 7', pumps 23' and 23'' are driven to circulate the heat medium in two lines, but the same as in the case of Fig. 1. It is.

In other words, since two pumps are installed, hydrogen is supplied to the hydrogen storage alloy in the container 7, and the heat is stored once in the heat storage container, but regardless of the time that the heat is stored, the pump 23'' can be operated to utilize the amount of heat in the heat storage container to release hydrogen from the hydrogen storage alloy 8'.

Even after the hydrogen storage operation is completed or in progress in one container, the heat can be used to release hydrogen in the other container.

Therefore, by performing such operations alternately, purified hydrogen gas can be extracted continuously and efficiently.

Furthermore, in Fig. 1, if the pump is operated continuously by changing the flow of the heat medium through the three-way valve from two directions to three directions,
The heat medium flows through the containers 7, 7' and the heat storage container, causing heat transfer, and it is also possible to simultaneously replace the amount of heat absorbed and released by hydrogen.

Next, the hydrogen purification effect using the apparatus configured as described above will be explained based on examples.

Example 1 TiMn1. as a hydrogen storage alloy. s was used.

That is, commercially available titanium (purity 99.5% or more) and manganese (purity 99.5% or more) were weighed so as to have a composition of TiMn1.5, and after heating and melting in an arc melting furnace,
The powder was pulverized to a particle size of about 10 to 50 meshes.

6.5kg of this alloy particle is directly 53nm, length 500
It was placed in a cylindrical container with an internal volume of about 21 mm and a hydrogen purification container.

The effective amount of hydrogen that can be stored in TiMn1.5 alloy is 0.18
1/g, the effective amount of hydrogen in the entire alloy is 1.17m
It is 3.

Note that in consideration of expansion due to hydrogen absorption of the alloy, the void inside the container was set to about 50%.

One set of such containers is connected via a heat storage container with a steel heat exchanger (serpentine tube) or the like.

A pump circulates the heat medium to alternately absorb and release hydrogen.

Water was used as a heat medium and was circulated at a flow rate of 51/min.

Water was also used as the solvent in the heat storage container.

Example 2 As shown in FIG. 2, a copper pipe for circulating a heat medium is meandered inside a hydrogen purification vessel.

The configuration is such that two lines of these paths are provided, and a heat medium is circulated by a pump in each line to perform heat exchange.

The amount of heat accumulated in the heat storage container is utilized during hydrogen occlusion or even after hydrogen occlusion is completed, to make hydrogen release more efficient.

All other conditions were the same as in Example 1.

According to the above example, the amount of hydrogen released and the purity of hydrogen were investigated.

First, if the containers 7 and 7' are not connected to each other for heat exchange, the hydrogen release pressure will drop to about 172 or less and the flow rate will not be able to maintain 101/min in less than 30 minutes after the start of hydrogen release. The flow rate gradually decreased until the total amount of hydrogen stored was 1.1.
It took approximately 6 hours to release up to 90% of the 7 m''.

On the other hand, when the absorbed heat of hydrogen is accumulated and this heat is used to release hydrogen, as in the example, the drop in hydrogen release pressure is smaller than in the conventional example, and the hydrogen release flow rate is more than 1 hour. The hydrogen rate was maintained at approximately 101/min, and in the second half, the rate was about 41/min on average, and 90% of the total amount of hydrogen stored was released in about 3 hours.

Further, the hydrogen effective utilization rates at flow rates of about 101/min and about 51/min were about 60% and about 90%, respectively, in the example, compared to about 30% and about 45% in the conventional example.

The rate of hydrogen release is closely related to the efficiency of heat exchange, and when the flow rate is large, it is necessary to ensure smooth heat exchange.

Even if care is taken to ensure that heat exchange proceeds efficiently, it does not necessarily proceed efficiently.

The case according to the embodiment is also superior to the conventional example, but when the flow rate is large, the hydrogen release pressure still decreases, making it difficult to release hydrogen.

In this case, the flow rate is lowered and the pressure is increased to release hydrogen.

Therefore, the smaller the flow rate, the higher the effective utilization rate of hydrogen.

As described above, according to the present invention, the hydrogen release flow rate that can be extracted is large, the hydrogen release time is short, and when a large amount of high-purity gas is required at once, it can be produced in a highly stable manner without using any other heat source. High purity hydrogen gas can be obtained intermittently or continuously.

Hydrogen stored in hydrogen storage alloys can be highly purified, but hydrogen storage alloys, especially TiMn mainly composed of TiMn15
Binary alloys, quaternary alloys such as TiMnZrCr, Ti
Titanium-manganese alloys, such as quinary alloys such as MnZrCrV, are very active compared to other alloys.

Since this alloy is easily formed into fine particles and has a very large surface area, it easily absorbs hydrogen, but also has the property that other gases are easily adsorbed or reacted with the alloy fine particles.

Therefore, since only hydrogen gas is released from the alloy, highly purified hydrogen gas can be obtained.

In this case, when a titanium-manganese alloy was used, the purity of the hydrogen gas passed through the hydrogen purification device was improved by one to two orders of magnitude.

In other words, industrial hydrogen gas purity of 99.9% is 99.99%.
Improved to 99,999% or more.

Although purity can be improved using other hydrogen storage alloys, titanium-manganese alloys have particularly significant effects.

This fact means that this alloy is active.

In addition, titanium-iron alloys, lanthanum-nickel alloys, mitshu metal-nickel alloys, etc. can also be used.

The hydrogen storage alloy used here preferably has a hydrogen release pressure of 1 to 20 atm at room temperature.

Below 1 atm, external means of heating is required;
If the pressure is 0 atm or higher, 40 atm or higher is required to absorb hydrogen, so a range within this range is optimal for hydrogen gas storage and purification.

As the heat medium, water and ethylene glycol are most suitable as materials that allow heat exchange with relative ease.

It is also desirable to use similar materials for the medium used in the heat storage container.

In addition, in the example, an apparatus in which two hydrogen gas purification containers were used as a set was used, but it is also possible to connect multiple sets in series to store hydrogen or to improve the purity of hydrogen gas.
Furthermore, they can be connected in parallel to increase the amount of hydrogen gas released.

Although the embodiment has been described as a hydrogen purification device, it can of course also be used as a hydrogen storage device.

As described above, according to the present invention, highly purified hydrogen gas can be obtained continuously or intermittently with high efficiency.

[Brief explanation of the drawing]

FIG. 1 is a diagram showing the overall configuration of an embodiment of the hydrogen purification apparatus of the present invention, and FIG. 2 is a diagram showing the configuration of main parts of another embodiment. 1...Container of hydrogen to be purified, 7,7'・song・
Hydrogen purification container, 8,8'...Hydrogen storage alloy, 1
7゜17', 21... Heat exchanger, 19... Old storage container.

Claims (1)

[Scope of Claims] 1. Occurrence when hydrogen is stored in one of the hydrogen purification containers equipped with at least one set of hydrogen purification containers containing hydrogen storage alloys that are connected to each other via a heat storage container so as to be able to exchange heat. 1. A hydrogen gas storage and purification device, characterized in that the amount of heat is stored in the heat storage container, and hydrogen is released from the container using the amount of heat. 2 The hydrogen release pressure of the hydrogen storage alloy is 1 to 2 at room temperature.
The hydrogen gas storage and purification device according to claim 1, wherein the hydrogen gas storage and purification device is at 0 atmospheric pressure. 3. The hydrogen gas storage and purification device according to claim 1, wherein the hydrogen storage alloy is a titanium-manganese alloy.