JP2010195643A - Method and system for generating hydrogen - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a hydrogen generating system for reducing the generation amount of hydrogen when hydrogen generation is not required, as much as possible. <P>SOLUTION: The hydrogen generating system is provided with: a storage material feeding tank 11 storing a mixture of hydrogen storage material powder and a nonaqueous and water-soluble preservative solution; a storage material recovering tank 12 recovering the residue after the hydrolysis of the hydrogen storage material fed from the storage material feeding tank 11; a water feeding tank 13 storing reaction water fed to the hydrolysis; and a reaction vessel 16 in which the hydrogen storage material in the mixture fed from the storage material feeding tank 11 and reaction water fed from the water feeding tank 13 are hydrolyzed, and, when the generation of hydrogen from the hydrogen storage material is required, to the reaction vessel 16, the hydrogen storage material is fed from the storage material feeding tank 11, and further, the reaction water is fed from the water feeding tank 13. <P>COPYRIGHT: (C)2010,JPO&INPIT

Description

The present invention relates to a method and system for generating hydrogen from a hydrogen storage material that generates hydrogen by hydrolysis of magnesium hydride (MgH ₂ ) or the like.

Due to the problems of global environmental conservation and fossil fuel depletion, fuel cells are considered as an alternative energy source to replace fossil fuels. Fuel cells are attracting attention because they use hydrogen and oxygen as raw materials and their exhaust gas is clean. Assuming that it is mounted on an automobile, about 5 kg of hydrogen is required to travel 400 to 500 km. Accordingly, there is a need for a hydrogen storage material that has a small storage volume and is lightweight. Among them, magnesium hydride (MgH ₂ ) has a theoretical hydrogen generation amount as high as 15.3% by mass and does not show an explosive hydrolysis reaction like lithium hydride (LiH). It is promising as a hydrogen storage material because it is low.

Magnesium hydride forms an inactive magnesium hydroxide film (Mg (OH) ₂ film) at the same time as the hydrolysis reaction proceeds, so the reaction does not proceed to completion. The present inventors have proposed one of the solutions in Patent Document 1 for this problem. That is, when magnesium hydride particles are given mechanical energy together with oxide particles consisting of one or more selected from Zn, Ni and Al, typically, mechanical pulverization, the hydrogen generation rate It was shown by patent document 1 that it can improve.

JP 2008-156148 A

When hydrolyzing magnesium hydride to generate hydrogen, not only water is added to the magnesium hydride but also heated to about 40 to 100 ° C. in order to promote the hydrolysis reaction. Actually, it is assumed that a slurry made of magnesium hydride powder and water is prepared in advance, and the slurry is heated to generate hydrogen when the fuel cell generates power. On the other hand, when the fuel cell does not generate electricity, it is not necessary to generate hydrogen from the hydrogen storage material. If the temperature of the slurry is kept at room temperature or lower, the hydrolysis reaction of magnesium hydride is remarkably slow, but the generation of hydrogen cannot be made zero. Therefore, since hydrogen is generated even when it is not necessary, the mileage of the vehicle due to a single replenishment of the hydrogen storage material is shortened, or it is necessary to replenish the hydrogen storage material by the amount of loss, The high hydrogen storage capacity of magnesium halide cannot be utilized effectively.
The present invention has been made based on such a technical problem, and an object thereof is to provide a hydrogen generation method capable of reducing the amount of hydrogen generation when it is unnecessary. Another object of the present invention is to provide a hydrogen generation system capable of carrying out this hydrogen generation method.

When the generation of hydrogen is unnecessary, the generation of hydrogen can be suppressed by setting the hydrogen storage material as a storage material mixture with a non-aqueous liquid. And if water is added to this storage material mixture and hydrolysis is carried out, hydrogen can be generated when necessary. The present invention is based on this finding and is characterized by having the following requirements.
A predetermined amount of the storage material mixture of the hydrogen storage material powder and the non-aqueous and water-soluble storage solution is retained in the first region. Further, a predetermined amount of reaction water for hydrolyzing the hydrogen storage material powder is held in a second region different from the first region. When generating hydrogen from the hydrogen storage material, the storage material mixture containing the hydrogen storage material is supplied from the first region to the reaction region, and the reaction water is supplied from the second region to the reaction region. To generate hydrogen from the hydrogen storage material.
According to the present invention, since the hydrogen storage material is dispersed and held in a non-aqueous and water-soluble storage solution, even if hydrogen is generated, it can be suppressed to a very small amount. Moreover, in the present invention, when it is necessary to generate hydrogen, the hydrogen storage material can be hydrolyzed by supplying it to the reaction region together with the reaction water.
In addition, in the present invention, after the hydrogen storage material is hydrolyzed, a residue generated by the hydrolysis is recovered from the reaction zone to the third zone in a timely manner, and thus does not hinder the subsequent hydrolysis.

  In the hydrogen generation method of the present invention, water generated by the power generation by the fuel cell is collected in the fourth region. Since the water collected in the fourth region can be reused as reaction water, an efficient method for generating hydrogen is obtained.

  In the hydrogen generation method of the present invention, after the storage material mixture in the first region has been supplied to the reaction region, the residue generated by hydrolysis can be recovered by causing the first region to function as the third region. preferable. After the storage material mixture has been fed to the reaction zone, the first zone is empty. Therefore, the residue is collected in the emptied first region. At this time, the storage material mixture is accommodated in the place where it was originally the third region, and functions as the first region. In this way, if the physically same region is made to function alternately in the first region and the third region, the supply of the storage material mixture (hydrogen storage material) and the recovery of the residual can be continuously performed by providing only two regions. Can be done automatically. Similarly, after the reaction water in the second region has been supplied to the reaction region, the second region functions as the fourth region, thereby recovering water generated by the power generation of the fuel cell. Preferred for.

  The preservation solution of the present invention is preferably ethylene glycol or propylene glycol. In the case of including a hydrogen storage material that generates hydrogen by hydrolysis, since both are non-aqueous, hydrolysis of the hydrogen storage material is suppressed. Moreover, since these substances are water-soluble, when reaction water is added, contact between the reaction water and the hydrogen storage material is hardly hindered, so that hydrolysis proceeds and hydrogen can be generated. Furthermore, since specific gravity is close to water (ethylene glycol: 1.113, propylene glycol: 1.036), it is easy to mix with water uniformly.

  In the above hydrogen generation method of the present invention, the first region to the fourth region can be embodied as a tank. Therefore, the hydrogen generation system of the present invention recovers the residue after the storage material supply tank containing the storage material mixture of the hydrogen storage material powder and the non-aqueous and water-soluble preservation solution, and the hydrogen storage material is hydrolyzed. A storage material recovery tank, a water supply tank containing reaction water supplied for hydrolysis, a storage material mixture supplied from the storage material supply tank, and a reaction water supplied from the water supply tank; A reaction vessel in which the storage material powder is hydrolyzed, and when hydrogen generation is required, the hydrogen storage material is supplied from the storage material supply tank to the reaction vessel, and the reaction water is supplied from the water supply tank. It is characterized by supplying.

  In the hydrogen generation system of the present invention, it is preferable that water generated by the fuel cell by generating electricity using hydrogen generated by hydrolysis is recovered in a water recovery tank. Since the collected water can be reused as reaction water, an efficient hydrogen generation system is obtained.

  In the hydrogen generation system of the present invention, it is preferable that the storage material supply tank functions as a storage material recovery tank after the storage material mixture in the storage material supply tank is supplied to the reaction vessel. That is, when the storage material supply tank becomes empty, the residue after hydrolysis is recovered in the empty storage material supply tank. At this time, the storage material mixture is supplied from another storage material supply tank containing the storage material mixture toward the reaction vessel. In the hydrogen generation system of the present invention, it is preferable that the water supply tank functions as a water recovery tank after the reaction water in the water supply tank has been supplied to the reaction vessel. That is, when the water supply tank becomes empty, the water generated by the fuel cell with power generation is recovered in the empty water supply tank. At this time, the reaction water is supplied from another water supply tank containing the reaction water toward the reaction vessel. In this way, it is not necessary to separately prepare an empty residue collection tank and a water collection tank from the beginning, which contributes to space saving of the hydrogen generation system.

  In the hydrogen generation system of the present invention, as the storage solution, ethylene glycol or propylene glycol is preferable as described above.

  According to the present invention, since the hydrogen storage material is dispersed and held in a non-aqueous and water-soluble storage solution, even if hydrogen is generated, it can be suppressed to a very small amount. Moreover, in the present invention, when it is necessary to generate hydrogen, the hydrogen storage material can be hydrolyzed by supplying it to the reaction region together with the reaction water.

The structure of the hydrogen generation system in this Embodiment is shown. It is a graph which shows the measurement result of the amount of hydrogen generation by various preservation solutions.

Hereinafter, the present invention will be described in more detail.
<Target hydrogen storage materials>
The present invention is directed to a hydrogen storage material that generates hydrogen by hydrolysis. As such a hydrogen storage material, lithium hydride (LiH), sodium hydride (NaH), calcium hydride (CaH ₂ ), magnesium hydride (MgH ₂ ), and the like are known. Widely applicable to storage materials. However, it is most preferable to target magnesium hydride (MgH ₂ ) because the theoretical hydrogen generation amount, hydrolysis reaction is moderate, and the cost is low. The hydrogen storage material in the present invention is used in the form of powder, and the average particle size of the particles is about 1 to 100 μm.
In addition, the hydrolysis reaction of magnesium hydride is performed according to the following formula.
MgH ₂ + 2H ₂ O → Mg (OH) ₂ + 2H ₂

<Non-aqueous and water-soluble storage solution>
The hydrogen storage material in the present invention is held in the first region (storage material supply tank) as a storage material mixture with a non-aqueous and water-soluble preservation solution. The reason why the preservation solution is made non-aqueous is to prevent the hydrogen storage material from undergoing a hydrolysis reaction, and non-aqueous is the most basic property required for the preservation solution. In addition, the preservation solution is required to be water-soluble. This is to ensure rapid contact between the hydrogen storage material contained in the storage material mixture and water when water is added to the storage material mixture for hydrolysis. The basic properties required for the preservation solution are the above two, but it is preferable that the preservation solution does not have toxicity to the human body and does not have volatility.

  Examples of the preservation solution that can be used in the present invention include aliphatic alcohols having up to 6 carbon atoms, alkylene glycols having 2 to 4 carbon atoms and alkyl ethers or dialkyl ethers thereof, and dialkylenes having 2 to 4 carbon atoms. Listed are glycols and their alkyl ethers or dialkyl ethers and aliphatic ethers having up to 6 carbon atoms. Among these, ethylene glycol and propylene glycol are preferable.

<Storage material mixture>
The hydrogen storage material in powder form is a storage material mixture with a preservation solution. If the content of the hydrogen storage material in the storage material mixture is small, the amount of generated hydrogen is insufficient. If the content is large, the viscosity increases and it becomes difficult to supply by a pump. It is more preferable to set it as the mass%. This storage material mixture is generally in the form of a slurry.
In a state where the hydrogen storage material is contained in the storage material mixture, it does not come into contact with water, so that hydrogen is not generated or is extremely small even if it is generated by hydrolysis. This is the same even when heating that promotes hydrolysis is performed. Thus, by holding | maintaining a hydrogen storage material as a storage material mixture with the preservation | save liquid in this invention, it can suppress that hydrogen is generated from a hydrogen storage material when it is unnecessary.

<Hydrogen generation in hydrogen storage materials>
In order to generate hydrogen using the storage material mixture according to the present invention, water (reaction water) is supplied to the storage material mixture. Since the preservation solution is water-soluble, the supplied water easily comes into contact with the hydrogen storage material, and a hydrolysis reaction occurs in the hydrogen storage material. The amount of water to be supplied is theoretically equivalent, but is preferably about 1.2 to 2.5 times the equivalent amount.
In order to accelerate the hydrolysis reaction, it is preferable to supply water to the storage material mixture under heating. The heating temperature can be appropriately selected within the range of 40 to 100 ° C. However, since this hydrolysis reaction is exothermic, heating is sufficient only at the beginning.
Similarly, an aqueous solution (reaction water) containing an acidic substance or a weakly basic substance can be used. By adding an acidic substance or a weakly basic substance, the pH in the solution can be fixed during the hydrolysis reaction. By doing so, the production | generation of Mg (OH) ₂ which inhibits hydrogen generation can be suppressed. The acidic substance preferably has an acid dissociation constant pKa of 4 to 9. The pKa of less than 4, acids stronger, the reaction proceeds rapidly, pKa effect of acid exceeds 9 prevents the formation of weak Mg (OH) ₂ can not be sufficiently obtained. Examples of such acidic substances include carboxylic acids such as hydrochloric acid, sulfuric acid, and acetic acid, carbonic acid, sodium hydrogen phosphate, and the like, which can be used in combination. As the weak basic substance, sodium hydrogen carbonate, potassium hydrogen carbonate, ammonium hydroxide and the like can be used. Moreover, as these substances, in order to maintain the pH fixing action, the concentration of the aqueous solution is, for example, hydrochloric acid: 0.001 to 0.1 mol / l, sulfuric acid: 0.001 to 0.1 mol / l, acetic acid : 0.01-1 mol / l, sodium bicarbonate: 0.01-1 mol / l, ammonium hydroxide: 0.01-1 mol / l.

<Hydrogen generation system>
Next, an embodiment of the hydrogen generation system will be described with reference to FIG.
The hydrogen generation system 10 according to the present embodiment is mounted on, for example, an electric vehicle and supplies hydrogen to the fuel cell system 20. The fuel cell system 20 includes a fuel cell that generates electricity by supplying hydrogen.

The hydrogen generation system 10 supplies the hydrogen storage material from the storage material supply tank (first region) 11 to the reaction vessel 16 in the form of the storage material mixture described above, and the reaction water from the reaction water supply tank 13 to the reaction vessel 16. By supplying the hydrogen storage material, a hydrolysis reaction is caused to generate hydrogen.
A storage material supply tank (first region) 11 stores and holds a predetermined amount of storage material mixture composed of a hydrogen storage material and a storage solution. For example, the predetermined amount is determined so that the electric vehicle can generate an amount of hydrogen that can run sufficiently without replenishment of the hydrogen storage material. The same applies to reaction water. The storage material supply tank 11 is connected to the reaction vessel 16 through supply pipes L1 and L3, and the storage material mixture held in the storage material supply tank 11 passes through the supply pipes L1 and L3 (pump 15). The reaction vessel 16 is supplied.
The storage material supply tank 11 is detachably mounted at a predetermined position of the electric vehicle, for example, and can be freely connected to the supply pipe L1.

The reaction water supply tank (second region) 13 stores and holds a predetermined amount of reaction water that is supplied into the reaction vessel 16 and causes a hydrolysis reaction to occur in the hydrogen storage material. The reaction water held in the reaction water supply tank 13 is not limited to fresh water, but may be an aqueous solution containing an acidic substance or a weakly basic substance (reaction accelerator). The reaction water held in the reaction water supply tank 13 may be fresh water, and an acidic substance or a weakly basic substance may be supplied from the promoter supply container 17 to the reaction container 16 via the pipe L5.
The reaction water supply tank 13 is connected to the reaction vessel 16 through supply pipes L2 and L3, and the reaction water held in the reaction water supply tank 13 reacts through the supply pipes L2 and L3 (pump 15). It is supplied to the container 16.
The reaction water supply tank 13 is detachably mounted at a predetermined position of the electric vehicle, for example, and can be freely connected to the supply pipe L2.

  The supply pipe L1 connected to the storage material supply tank 11 and the supply pipe L2 connected to the reaction water supply tank 13 merge to be connected to the supply pipe L3. A pump 15 is provided on the supply pipe L <b> 3. When the pump 15 is operated, the storage material mixture (hydrogen storage material + preservation solution) and reaction water are supplied to the reaction vessel 16.

A heater 16 h is provided in the reaction vessel 16. By heating the heater 16h, the inside of the reaction vessel 16 is heated and maintained at a temperature of 40 to 100 ° C. to promote the hydrolysis reaction.
A stirring blade 16 f is provided in the reaction vessel 16. When hydrogen generation is required, the hydrolysis reaction is accelerated by rotating the stirring blade 16f.

One end of a recovery pipe L6 is connected to the reaction vessel 16, and the other end of the recovery pipe L6 is connected to a storage material recovery tank (third region) 12. When the generation of hydrogen is completed, the hydrogen storage material becomes a residue. For example, when the hydrogen storage material is MgH ₂ , Mg (OH) ₂ becomes a residue. Moreover, the preservation solution and reaction water supplied to the reaction vessel 16 together with the hydrogen storage material also become a residue. These residues are collected in the storage material collection tank 12 (third region) through the collection pipe L6.

  The reaction vessel 16 is connected to a supply pipe L7 that supplies hydrogen generated from the hydrogen storage material toward the fuel cell system 20. One end of a recovery pipe L8 is connected to the fuel cell system 20, and a water recovery tank 14 is connected to the other end of the recovery pipe L8. The water generated by the power generation by the fuel cell system 20 is collected in the water collection tank (fourth region) 14 through the collection pipe L8.

An operation example of the hydrogen generation system 10 will be described below.
A storage material supply tank 11 filled with a predetermined amount of storage material mixture according to the present invention is mounted at a predetermined position of the hydrogen generation system 10. Moreover, the reaction water supply tank 13 filled with the predetermined amount of reaction water is mounted. At this time, the storage material recovery tank 12 and the water recovery tank 14 are provided with a recovery space in the interior so that each of them can be recovered sufficiently. Of course, an empty storage material recovery tank 12 and a water recovery tank 14 may be used.

When the fuel cell system 20 generates electricity, the pump 15 is operated to supply a storage material mixture comprising a hydrogen storage material and a storage liquid from the storage material supply tank 11 and a reaction water from the reaction water supply tank 13. It is supplied to the reaction vessel 16 through the pipe L3. At this time, a residue due to the preceding hydrogen generation may remain in the reaction vessel 16, but it is preferable that the residue is small.
Since the reaction vessel 16 is maintained at a temperature of 40 to 100 ° C. by the heater 16h, hydrolysis is promoted and hydrogen is generated from the hydrogen storage material. This hydrogen is supplied to the fuel cell system 20 through the supply pipe L7. Since the hydrolysis reaction is an exothermic reaction, heating by the heater 16h is sufficient only at the beginning.

  The residue remaining in the reaction vessel 16 is preferably recovered in the storage material recovery tank 12 while power generation is not performed. Further, the water generated in the fuel cell system 20 is preferably recovered in the water recovery tank 14 while power generation is performed.

  When the fuel cell system 20 does not generate power, the pump 15 is stopped. Since the hydrogen storage material held in the storage material supply tank 11 does not come into contact with water, the generation of hydrogen can be prevented or can be suppressed to a very small amount even if it occurs.

If the storage material mixture in the storage material supply tank 11 is insufficient, the new storage material supply tank 11 filled with the storage material mixture is replaced with the storage material recovery tank 12. By doing so, the storage material supply tank 11 lacking the storage material mixture can now be used as the storage material recovery tank 12. For this purpose, the supply pipe L1 and the recovery pipe L6 are connected as follows. That is, the supply pipe L1 may be connected to a new storage material supply tank 11 (the position of the storage material recovery tank 12 in FIG. 1), and the recovery pipe L6 may be connected to the storage material supply tank 11 lacking the storage material mixture.
If the reaction water in the reaction water supply tank 13 is insufficient, the reaction water supply tank 13 is caused to function as a new water recovery tank 14. Further, the water recovery tank 14 that has recovered water from the fuel cell system 20 is caused to function as a new reaction water supply tank 13 this time. For that purpose, the supply pipe L2 and the recovery pipe L8 are connected as follows. That is, the supply pipe L2 is connected to a new reaction water supply tank 13 (position of the water recovery tank 14 in FIG. 1), and the recovery pipe L8 is connected to a new water recovery tank 14 (position of the reaction water supply tank in FIG. 1). That's fine

As described above, according to the hydrogen generation system 10, when generating electricity, the storage material mixture and the reaction water are supplied to the reaction vessel 16 to generate hydrogen. Otherwise, the hydrogen storage contained in the storage material mixture is stored. Generation of hydrogen from the material can be suppressed.
In addition, the hydrogen generation system 10 holds a predetermined amount of the storage material mixture in the storage material supply tank 11, and if the storage material mixture runs short, a new storage material supply tank 11 is loaded so as to generate permanent hydrogen. A system 10 can be constructed. Further, since the storage material supply tank 11 lacking the storage material mixture can be used for recovering the residue accumulated in the reaction vessel 16, it is possible to reduce the trouble of taking down the storage material supply tank 11 lacking the storage material mixture.
About the reaction water supply tank 13 and the water recovery tank 14, since the function of a supply tank and a recovery tank can be provided alternately, transshipment of a tank can be abbreviate | omitted.

Hereinafter, the present invention will be described based on specific examples.
Magnesium hydride (MgH ₂ ) powder was added to water, ethylene glycol, propylene glycol, and silicon oil as dispersion media to prepare a mixture (slurry). The content of magnesium hydride (MgH ₂ ) powder is 20% by mass of water, 46% by mass of ethylene glycol, 46% by mass of propylene glycol, and 46% by mass of silicon oil.

These slurries were put into a thermostat, and the amount of generated hydrogen was measured with a gas meter every arbitrary time. In addition, water maintained the thermostat at 4 degreeC, and ethylene glycol, propylene glycol, and silicon oil maintained the thermostat at 30 degreeC.
The results are shown in FIG. 2. Compared with the slurry in which magnesium hydride (MgH ₂ ) powder was added to water, the slurry in which magnesium hydride (MgH ₂ ) powder was added to ethylene glycol, propylene glycol or silicon oil was It can be seen that the occurrence of can be greatly reduced. In particular, when propylene glycol is used, the amount of hydrogen generation is small. In addition, even if it is ethylene glycol, propylene glycol, or silicon oil, it is understood that hydrogen generate | occur | produces because the reaction with the water | moisture content melt | dissolved in these occurred from the air.

Next, hydrogen was generated by hydrolysis using the prepared three types of slurry, and the hydrogen generation rate was measured. The hydrogen generation rate was calculated based on the hydrogen generation amount from the start of hydrogen generation to the lapse of 1 hour, with the theoretical hydrogen generation amount of magnesium hydride being 100%. Hydrolysis was carried out under heating (80 ° C.), using water (fresh water) as the reaction water, and using an acetic acid (0.4 mol / l) aqueous solution and a citric acid aqueous solution (2 mol / l).
The results are shown in Table 1, and a sufficient amount of hydrogen can be generated even when ethylene glycol, propylene glycol or silicone oil is used as the storage solution.

10 ... Hydrogen generation system,
11 ... Storage material supply tank (first region), 12 ... Storage material recovery tank (third region)
13 ... Reaction water supply tank (second region), 14 ... Water recovery tank (fourth region)
16 ... Reaction vessel 20 ... Fuel cell system

Claims (8)

A predetermined amount of a mixture of the hydrogen storage material powder and a non-aqueous and water-soluble storage solution is retained in the first region,
Holding a predetermined amount of reaction water for hydrolyzing the hydrogen storage material powder in a second region different from the first region;
When generating hydrogen from the hydrogen storage material, the mixture is supplied from the first region to the reaction region, and the reaction water is supplied from the second region to the reaction region to hydrolyze the hydrogen storage material. By decomposing, hydrogen is generated from the hydrogen storage material,
A method for generating hydrogen, wherein after the hydrogen storage material is hydrolyzed in the reaction region, a residue generated by the hydrolysis is recovered from the reaction region to a third region.   A method for generating hydrogen, comprising recovering, in a fourth region, water generated by a fuel cell that generates electricity using hydrogen generated by the hydrolysis. After supplying the mixture of the first region to the reaction region, the residue generated by the hydrolysis is recovered using the first region as the third region,
The water generated by the fuel cell generating power is collected with the second region as the fourth region after the reaction water in the second region has been supplied to the reaction region. Item 3. The method for generating hydrogen according to Item 1 or 2.   The method for generating hydrogen according to claim 1, wherein the preservation solution is ethylene glycol or propylene glycol. A storage material supply tank containing a mixture of hydrogen storage material powder and a non-aqueous and water-soluble storage solution;
A storage material recovery tank for recovering a residue after the hydrogen storage material is hydrolyzed;
A water supply tank containing reaction water to be supplied to the hydrolysis;
Containing the mixture supplied from the storage material supply tank and reaction water supplied from the water supply tank; and a reaction vessel in which hydrolysis of the hydrogen storage material powder is performed;
With
When hydrogen generation from the hydrogen storage material is necessary,
A hydrogen generation system, wherein the hydrogen storage material is supplied from the storage material supply tank to the reaction vessel, and the reaction water is supplied from the water supply tank.   A hydrogen generation system, wherein water generated in a fuel cell that generates electricity using hydrogen generated by hydrolysis is recovered in a water recovery tank. After supplying the mixture in the storage material supply tank to the reaction vessel, the storage material supply tank becomes the storage material recovery tank,
The hydrogen generation system according to claim 5 or 6, wherein after the reaction water in the water supply tank has been supplied to the reaction vessel, the water supply tank becomes the water recovery tank.   The hydrogen generation system according to claim 5, wherein the preservation solution is ethylene glycol or propylene glycol.

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