JP2015231920A - Hydrogen production apparatus - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide hydrogen production apparatus by a thermal reaction.SOLUTION: There is provided hydrogen production apparatus for producing hydrogen and oxygen from water by reactions 2Na+2NaOH→2NaO+HReaction (A) 2NaO→NaO+2Na Reaction (B) NaO+HO→2NaOH+1/2OReaction (C) (Total Reaction) HO→H+1/2O, and having NaOH accommodation container for conducting the reactions (A) to (C), a grinder, a water supply flow passage, a Na accommodation container, a heat exchanger, a Na supply flow, a hydrogen ejection flow for ejecting hydrogen generated in the Reaction (A), a Na collection flow for collecting Na obtained in the Reaction (B) and an oxygen ejection flow for ejecting oxygen obtained in the Reaction (C).

Description

  The present invention relates to a hydrogen production apparatus, and more particularly to a hydrogen production apparatus using a thermochemical reaction.

  The problem of environmental destruction such as global warming due to the finite nature of fossil fuels or carbon dioxide emitted from fossil fuels is regarded as one of the most important issues to be solved for modern society. Under such circumstances, hydrogen is attracting attention as the ultimate clean energy source, and various attempts have been made to produce hydrogen.

  Specifically, the hydrogen production system of Patent Document 1 produces hydrogen by a thermochemical method using spent waste heat of nuclear power.

  Moreover, the hydrogen production apparatus of Patent Document 2 includes a reaction vessel that holds a metal element, a water tank for supplying water to the reaction vessel, a laser that heats a metal element by heating a portion where the metal element contacts water, And a hydrogen extraction pipe for recovering the hydrogen gas produced by the reaction between the metal element and water and the reaction energy.

  Furthermore, in the hydrogen production method of Patent Document 3, the metal hydride is thermally decomposed to obtain an arbitrary amount of hydrogen, and then the remaining metal hydride without decomposition is reacted with water to produce hydrogen. Hydrogen is produced by reacting a metal by-produced by thermal decomposition of a hydride with an aqueous alkali solution.

JP 2006-282413 A JP 2007-145686 A JP 2009-001457 A

  The hydrogen production system based on the thermochemical reaction described in Patent Document 1 has been expected as a direct use of energy, but this thermochemical reaction has a reaction temperature of about 1000 ° C., and the reaction at this temperature is realized. It is necessary to increase the loss of auxiliary equipment and to make the reaction vessel material heat resistant. Furthermore, since the hydrogen produced is also hot, it must be equipped with a cooling means. As a result, the overall size of the hydrogen production apparatus becomes large and the weight increases accordingly, and there are various problems in practical use.

  Moreover, although the hydrogen production apparatus and method described in Patent Documents 2 and 3 can be implemented with a relatively small apparatus as compared with the system described in Patent Document 1, the spent hydrogen used in the hydrogen production reaction is used. There is a problem that the generated material cannot be regenerated on the spot.

  Therefore, a hydrogen generator that is small in size and capable of generating hydrogen from the hydrogen generating material and regenerating the used hydrogen generating material on the spot is desired.

  In order to solve these problems, a repetitive cycle using the following reaction that can proceed at about 400 ° C. to 500 ° C. can be considered.

_{2Na + 2NaOH → 2Na 2 O +} H 2 300 ℃ before and after the reaction (A)
2Na ₂ O → Na ₂ O ₂ + 2Na 400 ° C. to 500 ° C. Reaction (B)
Na ₂ O ₂ + H ₂ O → 2NaOH + 1 / 2O ₂ Room temperature to several tens of degrees C. Reaction (C)
(Total reaction) H ₂ O → H ₂ + 1 / 2O ₂

  However, there are various problems in applying the above reaction to an actual system.

  Specifically, first, in the above cycle, improvement of the cycle rate is desired. The reason why the cycle rate is low is that NaOH is agglomerated, which makes it difficult to raise the temperature of all NaOH to a predetermined temperature for reaction (A). It does not react. For this problem, it is conceivable to increase the amount of Na. However, if the excess Na is not recovered sufficiently, it reacts with water during the reaction (C) to generate NaOH, which causes the balance between the amount of NaOH and Na to be lost. Therefore, simply increasing Na is not a sufficient response.

  Furthermore, it takes time to exceed 300 ° C. or 400 ° C., which is the temperature required for the reaction (A) or (B). Therefore, when the time in which heat from the outside can be used is short, the substantial reaction time of these reactions is short, and it is difficult to obtain a sufficient reaction.

  In addition, Na reacts actively with water vapor to become NaOH even when exposed to air. Since NaOH is a strong alkaline reagent, it is necessary to construct a system so that it does not adhere to the human body or be discarded outside. Therefore, it is desired to construct a closed system in which Na or the like circulates in the system without touching the outside.

  In order to adapt the above reaction to an actual system, it is desired to solve these problems.

The present inventors have intensively studied and found that the above problems can be solved by the following means:
<1> A hydrogen production apparatus for producing hydrogen and oxygen from water,
_{2Na + 2NaOH → 2Na 2 O +} H 2 reaction (A)
2Na ₂ O → Na ₂ O ₂ + 2Na reaction (B)
Na ₂ O ₂ + H ₂ O → 2NaOH + 1 / 2O ₂ reaction (C)
(Total reaction) H ₂ O → H ₂ + 1 / 2O ₂
To produce hydrogen and oxygen from water; and contain NaOH (sodium hydroxide) to carry out the above reactions (A) to (C);
A pulverized NaOH pulverizer for pulverizing the NaOH contained in the NaOH container;
A water supply channel for supplying water to the NaOH container;
Na containing container for containing Na (metallic sodium),
A heat exchanger disposed in the Na container;
Na supply flow path for supplying Na melted by heating with the heat exchanger from the Na container to the NaOH container,
A hydrogen discharge flow path for discharging hydrogen generated by the reaction (A) from the NaOH container;
Na recovery flow path for recovering Na obtained by the reaction (B) from the NaOH storage container to the Na storage container, and oxygen discharge flow path for discharging oxygen obtained by the reaction (C) from the NaOH storage container With
Hydrogen production equipment.

  According to the present invention, it is possible to provide a hydrogen production apparatus that is small in size and capable of generating hydrogen from a hydrogen generating material and regenerating used hydrogen generating material on the spot.

  According to the present invention, the cycle rate of the above reactions (A) to (C) can be improved, and the reaction rate can be increased. This is because the agglomerated NaOH can be crushed and reacted immediately by supplying Na thereto.

  In addition, according to the present invention, the yield of hydrogen generation can be significantly increased as compared with the case not according to the present invention. This means that Na and water react to generate NaOH by sufficiently recovering excess Na before the reaction between NaOH and water, and forming a closed system in which Na does not come into contact with air. This is because the balance of the amount of NaOH and Na is not easily lost.

It is the figure which showed the hydrogen production apparatus by this invention.

  Embodiments of a hydrogen production apparatus according to the present invention will be described below with reference to the drawings.

<Hydrogen production equipment>
As shown in FIG. 1, one aspect of the present invention is a hydrogen production apparatus (20) for producing hydrogen and oxygen from water,
_{2Na + 2NaOH → 2Na 2 O +} H 2 reaction (A)
2Na ₂ O → Na ₂ O ₂ + 2Na reaction (B)
Na ₂ O ₂ + H ₂ O → 2NaOH + 1 / 2O ₂ reaction (C)
(Total reaction) H ₂ O → H ₂ + 1 / 2O ₂
In this reaction, hydrogen and oxygen are produced from water; and NaOH (1) is accommodated, and the above-mentioned reactions (A) to (C) are performed. The NaOH accommodating container (2) and the NaOH accommodating container (2) are accommodated. Crushing the NaOH (1), optionally crushing machine (3) operating in the vertical direction (3a), water supply channel (4) for supplying water to the NaOH container (2), Na (5) Na containing container (6), heat exchanger (7) disposed in the Na containing container (6), and Na melted by heating by the heat exchanger (7) are added to the Na containing container (6). ) To supply the NaOH container (2) to the NaOH supply container (2), an optional Na pump (8a), and hydrogen discharge for discharging the hydrogen generated by the reaction (A) from the NaOH container (2). Flow path (9) and optional hydrogen filter (9a), an Na recovery channel (10) for recovering Na obtained by the reaction (B) from the NaOH container (2) to the Na container (6), an optional Na filter (10a), and the above A hydrogen production apparatus (20) comprising an oxygen discharge channel (11) for discharging oxygen obtained by the reaction (C) from the NaOH container (2) and an optional hydrogen filter (11a).

(NaOH container)
In the present invention, the NaOH container (2) means any container that contains NaOH (1) and performs the above reactions (A) to (C). This NaOH containing container (2) can be heated and optionally cooled to allow reactions (A)-(C).

In the NaOH container (2), the reactions (A) and (B) may proceed separately or may proceed simultaneously. For example, when used on-vehicle, reactions (A) and (B) proceed in a temperature range of 400 ° C. or higher while Na ₂ O ₂ , Na ₂ O, and NaOH exist in a mixed state. Thereafter, the exhaust temperature slightly decreases in the idling state during the signal waiting time, but this reaction can be continued if the engine is on.

(Crusher)
In this invention, a grinder (3) means the arbitrary grinders which grind | pulverize and grind | dissolve NaOH (5) accommodated in the NaOH container (2).

  Since NaOH is solid and aggregates due to deliquescence, the reaction amount is small even if Na (liquid) (5) is simply mixed. Therefore, pulverization is performed by the pulverizer (3) as much as necessary for the reaction.

  The pulverizer (3) is a rotary type as an example. The pulverizer (3) has a protrusion in the disk, and is pulverized from the surface by rotating while pressing against NaOH (1). Moreover, it is preferable that the pulverizer (3) operates in the vertical direction (3a). By making the surface of NaOH (1) in the NaOH container (2) as flat as possible and uniformly scraping it with a crusher, the reaction with Na (5) is performed most efficiently and in a short time. Can do.

(Water supply flow path)
In the present invention, the water supply channel (4) means an arbitrary channel for supplying water to the NaOH container.

When the reaction scheduled NaOH finishes the reaction, the inside of the NaOH container (2) is Na ₂ O, Na ₂ O ₂ and a part of NaOH. In this state, water necessary for the reaction (C) is supplied to the NaOH container (2) through the water supply channel (4). This produces NaOH and oxygen from Na ₂ O ₂ in reaction (C).

  The water supply channel (4) may have an optional water tank. In order to always keep the same amount of water in the water tank, the water tank is operated by sequence control to supply water vapor in the exhaust gas when the amount of water is insufficient and supply when there is a surplus. Can be stopped.

The water supplied by the water supply channel (4) may be water contained in the exhaust gas. This exhaust gas contains CO _2, but there is no problem because it is inert to the above reaction. By using the water contained in the exhaust gas, hydrogen and oxygen can be generated using the exhaust heat, and this hydrogen and oxygen can add new added value to the automobile.

  The water supplied by the water supply channel (4) can be supplied at an arbitrary temperature, for example, at a temperature of room temperature to several tens of degrees Celsius.

The water supplied by the water supply channel (4) may be supplied slightly more than the amount stoichiometrically commensurate with Na ₂ O ₂ . In this case, it is preferable to design the apparatus so that water is supplied at a temperature of 120 ° C. or higher, and excess water does not become less than 100 ° C. even if the temperature subsequently decreases.

When water is supplied excessively, water vapor is generated. Therefore, it is preferable to discharge this water vapor when Na ₂ O ₂ changes to NaOH. For this reason, an optional water vapor discharge channel for discharging water vapor from the NaOH container may be provided.

  The water vapor discharge channel may communicate with the outside of the apparatus or may communicate with the water tank. Since NaOH is dissolved in this water vapor, the water vapor discharge channel preferably has a water vapor filter for allowing only water vapor to pass therethrough.

(Na container)
In the present invention, the Na storage container (6) means an arbitrary container that stores Na (5).

  In order to prevent the reaction between water and Na, the NaOH container (2) and the Na container (6) supplied with water from the water supply channel (4) need to be separate containers.

  For example, as shown in FIG. 1, NaOH (1) and NaOH container (2) may be installed in a high part, and Na container (6) may be installed in the lower part, and vice versa. Further, the NaOH container (2) and the Na container (6) may be arranged side by side.

(Heat exchanger)
In the present invention, the heat exchanger (7) is an arbitrary heat exchanger capable of heating and melting Na in the Na container (6). For example, when the hydrogen production apparatus of the present invention is used on board, this heat exchanger may be a heat exchanger that heats Na (5) by engine exhaust heat.

(Na supply flow path)
In the present invention, the Na supply flow path (8) is an arbitrary flow path for supplying Na melted by heating by the heat exchanger (7), for example, molten Na of 400 ° C. or more to the NaOH container (2). means.

  Here, the Na supply channel (8) may have an optional Na supply pump (8a) between the NaOH container (2) and the Na container (6). The Na supply pump (8a) may be a normal gear pump, a bellows pump, or a pump using a PZT element.

Na (5) can be supplied in an amount stoichiometrically commensurate with crushed NaOH (1). Na (5) is preferably mixed with NaOH (1) in a temperature range of 400 ° C. or higher. Generating a Na ₂ O and hydrogen from NaOH by the reaction of the (A).

(Hydrogen discharge flow path)
In the present invention, the hydrogen discharge flow path (9) means an arbitrary flow path for discharging hydrogen generated by the reaction (A).

  Here, when hydrogen is generated by the reaction (A), the vapor of Na (5) may be mixed with hydrogen. In order to prevent this, an optional hydrogen filter (9a) that allows only hydrogen to permeate can be used. The hydrogen filter (9a) may be, for example, a pressed film in which single-walled carbon nanotubes are dispersed (coalescence).

  The hydrogen discharge channel (9) can be connected to an engine, for example. By doing so, hydrogen can be utilized as an effective energy source or a reducing raw material such as NOx.

(Na recovery flow path)
In this invention, Na collection | recovery flow path (10) means the arbitrary flow paths which collect | recover Na (5) obtained by reaction (B) from NaOH storage container (2) to Na storage container (6).

  In one embodiment, the Na recovery channel (10) may have an optional Na filter (10a) having holes with a pore diameter of several tens to several hundreds of micrometers. In this case, excess Na (5) can be recovered through the hole into the Na container (6) below NaOH (1) by natural fall.

  In another embodiment, the Na recovery channel (20) may have a pump. This pump may be the pump mentioned for the Na feed pump (8a).

(Oxygen discharge flow path)
In the present invention, the oxygen discharge flow path (11) means an arbitrary flow path for discharging oxygen obtained by the reaction (C) from the NaOH container (2).

  The oxygen discharge channel (11) can be connected to an engine, for example. By doing so, it is possible to increase the oxygen concentration in the engine and contribute to an increase in output.

  Here, oxygen contains some water vapor, and NaOH may be dissolved in the water vapor. Since the temperature of the outside of the NaOH container (2) is lower than that of the inside of the container, there is a risk that this NaOH will solidify and the channel will be clogged. In order to prevent this, by installing an optional gas-liquid separation filter (11a) in the oxygen discharge channel (11), it is possible to separate water vapor and release only oxygen. The gas-liquid separation filter may be the filter mentioned for the hydrogen filter (9a).

1 NaOH
2 NaOH container 3 Crusher 3a Direction of operation of crusher 4 Water supply flow path 5 Na
6 Na container 7 Heat exchanger 8 Na supply flow path 8a Na pump 9 Hydrogen discharge flow path 9a Hydrogen filter 10 Na recovery flow path 10a Na filter 11 Oxygen recovery flow path 11a Gas-liquid separation filter 20 Hydrogen production device

Claims (1)

A hydrogen production apparatus for producing hydrogen and oxygen from water,
_{2Na + 2NaOH → 2Na 2 O +} H 2 reaction (A)
2Na ₂ O → Na ₂ O ₂ + 2Na reaction (B)
Na ₂ O ₂ + H ₂ O → 2NaOH + 1 / 2O ₂ reaction (C)
(Total reaction) H ₂ O → H ₂ + 1 / 2O ₂
To produce hydrogen and oxygen from water; and to contain NaOH and carry out the reactions (A) to (C);
A crusher for crushing the NaOH contained in the NaOH containing container;
A water supply channel for supplying water to the NaOH container;
A Na container for containing Na,
A heat exchanger disposed in the Na container,
Na supply flow path for supplying Na melted by heating by the heat exchanger from the Na container to the NaOH container,
A hydrogen discharge flow path for discharging hydrogen generated by the reaction (A) from the NaOH container;
Na recovery flow path for recovering Na obtained by the reaction (B) from the NaOH storage container to the Na storage container, and oxygen discharge flow path for discharging oxygen obtained by the reaction (C) from the NaOH storage container With
Hydrogen production equipment.

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