JPS5829242B2 - hydrogen generator - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a hydrogen generating device that generates hydrogen by reacting a metal hydride with water.

It has long been known that hydrogen is generated when water reacts with metal hydrides such as lithium hydride and calcium hydride. It has found practical use as a simple hydrogen source.

FIG. 1 is a diagram showing the principle of an example of this type of simple hydrogen generator. Water in a water tank 2 is fed under pressure to a reactor 3 using a manual air pump 1, and this water (hereinafter referred to as "reaction water") is shown in FIG. ) is reacted with calcium hydride 4 in the reactor 3, and the hydrogen generated based on the reaction formula CaH2+2H20→Ca(OH)2+2H2 is sent to a hydrogen consuming device, such as an air-hydrogen fuel cell, via a pressure regulator 5. supply.

In FIG. 1, check valves, control valves, safety valves, etc. are shown without particular reference numerals, but their explanations will be omitted.

By the way, when a hydrogen generator based on this principle is put into practical use, highly pure hydrogen gas is obtained at the beginning of the reaction, but at the end of the reaction, a considerable amount of water vapor is mixed into the hydrogen gas. There is a problem of reducing hydrogen gas purity.

The reason for this is that there is heat generated by the reaction in the above reaction equation, and in the early stages of the reaction, this reaction heat is used to immediately vaporize the supplied reaction water and cause the reaction. In order to speed up the reaction, the reaction water is guided below the calcium hydride deposit in reactor 3, but as the reaction progresses and the amount of unreacted metal hydride decreases, the water vapor that does not participate in the reaction becomes hydrogen. This results in a situation where the gas leaks out to the outside together with the gas.

SUMMARY OF THE INVENTION Therefore, an object of the present invention is to provide a hydrogen generator capable of eliminating the above-mentioned drawbacks and supplying hydrogen without contamination with water vapor.

Another object of the present invention is to provide a hydrogen generator that can continuously supply hydrogen to hydrogen consuming equipment.

That is, when the reaction of metal hydride progresses and all of it is converted to metal hydroxide, the metal hydride is reinjected into the reactor 3, or a new one filled with unreacted metal hydride is added. It is necessary to replace the reactor, etc.
In one hydrogen generator, the supply of hydrogen is forced to be interrupted while such work is performed.

To solve this problem, it is possible to use two reactors and switch between them, but the problem of water vapor contamination still cannot be solved by simple switching.

Therefore, in the present invention, two reactors are installed so that each reactor can be operated independently, and during normal operation, the two reactors are connected in series, that is, the hydrogen generated in one reactor is transferred to the other reactor. The reaction water is supplied to the reaction water supply line, and the hydrogen that has passed through the other reactor is supplied to the hydrogen consuming equipment.

By doing this, even if the reaction in one of the reactors progresses and the generated hydrogen contains water vapor, this water vapor is absorbed by the metal hydride in the subsequent reactor, so the final output gas is It will not be mixed in.

Naturally, in the latter reactor, hydrogen is additionally generated due to the absorption of water vapor, but as is clear from the above reaction equation, 2 moles of water vapor gas
Since moles of hydrogen gas are generated, the overall amount of hydrogen generated is always kept uniform.

Therefore, according to the present invention, the above two objects can be solved at once.

Next, embodiments of the present invention will be described based on the drawings.

Fig. 2 is a piping system diagram of an embodiment of the present invention, and Figs. 3 to 6 are piping system diagrams showing only the pipes through which reaction water and hydrogen gas flow during various operation modes. , common parts in all figures are given common reference numerals.

In FIG. 2, 6 is a water tank and is equipped with means (not shown) for applying appropriate pressure for pumping water.

7 is a water supply valve, and 8 is a throttle. A certain amount of reaction water that has passed through the throttle 8 is selectively supplied to two systems by a three-way switching valve 9.

One system is a system with reactor 10 and the other system is a system with reactor 20.

These reactors may be of the same type as reactor 3 in FIG. 1, for example.

10a and 20a are reaction water supply pipes, and 10b. 20b is a hydrogen discharge pipe.

Also, 11.21 and 13.23 are check valves, 12.2
2 is a three-way switching valve, 24 is a hydrogen gas supply valve, and the hydrogen gas that has passed through the hydrogen gas supply valve 24 is optionally passed through a surge tank, and preferably via a pressure regulator to a hydrogen consuming device, such as an air- Supplied to hydrogen fuel cells.

The device of the embodiment of FIG. 2 with three three-way valves 9, 12, 22 can be operated in four operating modes as described below.

As shown in FIG. 3, in the first operation mode, the three-way switching valve 9 is switched to the check valve 11 side to supply reaction water to the reactor 10, and the three-way switching valve 12 is switched to the check valve 13 side. The hydrogen generated in the reactor 10 is transferred to the reaction water supply pipe 2 of the reactor 20.
0a, and the three-way switching valve 22 from the hydrogen discharge pipe 20b.
This is a mode in which high-purity hydrogen is introduced to the hydrogen gas supply valve 24 through the hydrogen gas supply valve 24.

In this mode of operation, the water vapor contained in the hydrogen generated in the reactor 10 is absorbed by the metal hydride in the reactor 20, and together with additionally generated hydrogen, is supplied to hydrogen consuming equipment as high purity hydrogen gas.

When the reaction of the metal hydride in the reactor 10 is almost completed, the pressure drop can be detected by, for example, a pressure gauge or a pressure alarm device installed in the pressure regulator, and the reactor 20 is in the next operation mode. Perform operation using a chisel (Fig. 4).

In the operation mode shown in FIG. 4, reaction water is supplied from the three-way switching valve 9 to the reaction water supply pipe 20a of the reactor 20 via the check valve 21.

The three-way valve 12 in FIG. 3 is opened and the reactor 10 is removed from reacted metal hydride and filled with fresh metal hydride.

Since most of the metal hydride in the reactor 20 is unreacted, by switching the operation mode, hydrogen gas can be supplied continuously and without mixing any water vapor even though the operation of the reactor 10 is stopped. It becomes possible to do so.

When the preparation of the reactor 10 is completed, the third
enters driving mode.

In this mode of operation, the order of reactors 10 and 20 is reversed from the first mode of operation shown in FIG.

That is, hydrogen gas generated in the reactor 20 is supplied from the hydrogen discharge pipe 20b to the reaction water supply pipe 10a of the reactor 10 via the three-way switching valve 22 and the check valve 23, and the reaction gradually contains water vapor. The hydrogen generated in the reactor 20 is absorbed by the almost unreacted metal hydride in the reactor 10 and converted into high-purity hydrogen gas, a hydrogen discharge pipe 10b1, a three-way switching valve 12,
The hydrogen is supplied to the hydrogen consuming equipment via the hydrogen supply valve 24.

As the operation continues in this mode, a time will come when the metal hydride in the reactor 20 has almost completed its reaction, so this is detected by the pressure drop as described above, and the next operation mode is started. That is, the operation mode of only the reactor 10 shown in FIG. 6 is entered.

Since this operation mode is the reverse of the independent operation mode of the reactor 20 shown in FIG. 4, detailed explanation will be omitted.

Then, when the reactor 10 is operated independently, the metal hydride in the reactor 20 is replaced and the first operation mode shown in FIG. 3 is entered.

The following is a repetition of the above.

Among the four operation modes described above, the most distinctive feature of the present invention is the reactor 10 shown in FIGS. 3 and 5.
．． It will be clear that there are 20 series operating modes.

By making this series operation mode the constant operation mode, it is possible to obtain high-purity hydrogen gas that does not contain water vapor, and as a secondary effect, moisture does not condense in the gas system piping. The problem of corrosion is also reduced, and the piping configuration becomes extremely easy.

Note that when implementing the present invention, if you are particularly concerned about a temporary drop in output gas pressure when switching the three-way switching valve,
As mentioned above, measures may be taken such as attaching a surge tank or, if the hydrogen consuming device is an air-hydrogen twisted 7-fuel cell, connecting a normal storage battery in parallel to the fuel cell.

[Brief explanation of drawings]

Figure 1 is a system diagram showing the principle of a conventional hydrogen generator;
The figure shows a piping system diagram of an embodiment of the present invention, and Figures 3 to 6 show only the piping system and equipment involved in each of the four operating modes of the embodiment of Figure 2. It is a system diagram. 6...Water tank, 9,12,22...
Three-way switching valve, 10.20... Reactor, 11.1
3,21゜23...Check valve, 24...
Hydrogen supply valve.

Claims (1)

[Scope of Claims] 1. At least two reactors that generate hydrogen through a reaction between a metal hydride and reaction water; a piping system that selectively supplies reaction water to each of the reactors; It is equipped with a piping system that selectively supplies the hydrogen generated from one reactor to the reaction water supply line of the other reactor and the hydrogen consuming equipment, and is characterized in that during normal operation, each reactor is connected in series. hydrogen generator. 2. A hydrogen generator according to claim 1, wherein the portion controlling selective supply of each piping system is a three-way switching valve.