JP6203481B2 - Reagent pretreatment method for hydrogen generator - Google Patents

Description

  The present invention relates to a pretreatment method for a reactant used in a hydrogen generator that collects hydrogen from water.

  The alkali metal molten salt as a reactant is stored in a stainless steel reaction cell, heated to 500 ° C. or more to emit fine particles from the molten salt, the fine particles react with water vapor, and water is added. The present inventor has filed a few applications for a hydrogen generator that decomposes and generates hydrogen.

International Publication 2010/84790 JP2010-1555086

  However, sodium hydroxide or potassium hydroxide as a reactant in Patent Documents 1 and 2 has a strong hydrophilicity, not only significantly absorbs moisture in the air, but also deteriorates when exposed to air, Since the reaction also has a great influence, pretreatment is required so as not to be affected by air.

  Therefore, in the first invention of the present invention, alkali metal hydroxides such as sodium hydroxide (NaOH) and potassium hydroxide (KOH) as a reactant are accommodated in a stainless steel reaction vessel via a reactant receiver, In a pretreatment method for a reactant in a hydrogen generator in which the reactant is heated and water vapor is brought into contact with the reactant to generate hydrogen, the reactant is melted by heating it above its melting point in an oxygen-free atmosphere. Then, a predetermined amount of this molten liquid is injected into a reagent receiver installed in the oxygen-free atmosphere, and the reagent receiver is installed in the reaction cell in an oxygen-free atmosphere so that the reaction cell is sealed by electron beam welding. I made it.

  The oxygen-free atmosphere is formed by a vacuum vessel, and a heating kettle is installed in the vacuum vessel, and the reactant heated and melted by the heating kettle is supplied to a reactant receiver installed in the vacuum vessel. It is preferable.

  Furthermore, the oxygen-free atmosphere is preferably formed of an inert gas such as argon or nitrogen.

  Further, the second invention of the present invention is to generate hydrogen from water by collecting a high-order iron oxide film as a reactant in a reaction vessel and bringing the water vapor into contact with the iron oxide film while heating. In the pre-treatment method for the reactants in the apparatus, alkali metal hydroxides such as sodium hydroxide (NaOH) or potassium hydroxide (KOH) are melted by heating them in an oxygen-free atmosphere to a temperature above their melting point. Is injected into a receiving container in an oxygen-free atmosphere, and the receiving container is heated in an oxygen-free heating container covered with a stainless steel plate to form a high-order iron oxide film disposed in the heating container. A low-order iron oxide film was formed on the plate, and the low-order iron oxide film-formed plate on which the iron oxide film was formed was housed in the reaction cell.

  Moreover, it is preferable that the said receiving container is SUS304 of a 18Cr-8Ni-74Fe component.

  By heating NaOH or KOH in vacuum or in an inert gas atmosphere to form molten salt, water as a hydrate contained in these reactants, moisture absorbed during storage, and oxygen in the air can be released. If the molten salt from which this impurity has been released is injected into a reagent receiver in an oxygen-free atmosphere, and the reagent receiver is stored in an oxygen-free atmosphere in the reaction cell and electron beam welding is performed, the reaction cell can be sealed as it is. The reactant can be accommodated in the reaction cell without touching any oxygen in the air, and the reaction period can be significantly increased.

  In addition, when low-order iron oxide formed from KOH or KaOH and stainless steel is stored in a reaction cell and water is decomposed to collect hydrogen, the low-order iron oxide film is formed in an oxygen-free state. When this is stored in the reaction cell, it can be a reaction cell having a function of decomposing water for a long time.

It is sectional drawing of the reaction cell which accommodated the reactive agent. It is a schematic block diagram of the reaction agent process in a vacuum vessel. It is a block diagram of the argon box which preserve | saves a reagent receiver in inert gas atmosphere. It is a schematic block diagram in the vacuum vessel provided with the electron beam welding apparatus. It is a schematic block diagram of a low-order iron oxide film formation apparatus. It is a perspective view of the high-order iron oxide film formation board which adhered the low-order iron oxide film on the adhesion board. It is a state diagram in the reaction cell which accommodated the low-order iron oxide film.

Hereinafter, embodiments of the present invention will be described with reference to the drawings.
In FIG. 1, a hydrogen generator M according to the present invention has a cylindrical reaction cell 1 made of stainless steel (SUS04: Cr18% -Ni8% -Fe74%), and this reaction cell 1 has water at one end. Alternatively, a water supply port 2 for supplying water vapor is provided, a hydrogen discharge port 3 is provided at the other end, and a reagent receiver 4 made of stainless steel (SUS304) is provided in the inside, and this reactant is provided. A reactant 5 is accommodated in the receptacle 4. As the reactant 5, alkali metal hydroxides such as sodium hydroxide (NaOH) and potassium hydroxide (KOH) are used, and the reactant is heated to a temperature higher than the melting point of the reactants (NaOH: 318 ° C., KOH: 360 ° C.), preferably 500 to 600 ° C. When the reactant is heated above its melting point, it melts to form a molten salt, and fine particles P ₁ scatter from the surface of the molten salt, and the fine particles react with water vapor to decompose water. Hydrogen is generated.

In such a stainless steel component atmosphere (Fe, Cr, Ni), fine particles (NaOH, KOH) P and water vapor react with each other to produce a low-order iron oxide (for example, Na ₂ FeO ₂ , NaFeO _{2 in} the case of NaOH). ) has been observed to make, but this time, can not pure low order iron oxide when impurities are contained in water or the like which is moisture in the oxygen or air in the air into fine particles P ₁ It is considered that the oxide has a low reactivity and has a low ability to decompose water, and its catalytic function is short-lived. NaOH and KOH have extremely high hydrophilicity and have a property of absorbing moisture and deliquescent when exposed to air during storage before use, and are severely degraded when left in the air. In the reaction without water or water vapor, a low-order iron oxide film is generally generated, but sometimes a high-order iron oxide film is sometimes generated.

  Therefore, pretreatment of the reactant is required, and the reactant 5 is first treated in the first vacuum vessel 10 as shown in FIG. A heating pot 11 is disposed in the first vacuum vessel 10, and the heating pot 11 is made of stainless steel (SUS304) or ceramics. The heating pot 11 has a vertical container 12 around which a sheet heater 13 is wound, and a stirring blade 14 is provided in the heating pot 11. The reactant 5 is heated in the heating kettle 11 to about 400 ° C. with the stirring blade 13 for 3 to 4 hours. As a result, water as a hydrate mixed in the reactant 5 and oxygen and water vapor in the sucked air are released, and this released gas is discharged from the discharge port 10a of the vacuum vessel 10 by the pump 15. . The molten salt of the reactant thus treated is supplied into the reactant receptacle 4 disposed below the valve 17 of the spout 16 provided at the bottom thereof. The reactant receiver 4 is made of stainless steel, is moved by a conveyor 18 provided at the bottom of the vacuum vessel 10, and is transferred to an argon box 30 shown in FIG.

  The argon box 30 includes a box-shaped main body 31 and a lid box 32 that can be opened and closed. The space formed by the main body 31 and the lid box 32 is filled with argon gas supplied from an argon tank 33. In the box-shaped main body 31, a reactant receiver 4 containing the solidified reactant 5 is accommodated, and the reactant receiver 4 kept in an oxygen-free state thereby has an electron beam as shown in FIG. The opening / closing door 42 is opened in a second vacuum vessel 41 equipped with a welding device 40 and inserted into the reaction cell 4 with one end opened. Thereafter, the end plate 1a of the reaction cell 1 is set at the open end, and the surrounding portion C is sealed by electron beam welding.

  If the reactant receiver 4 is accommodated in the reaction cell 1 in this manner, the reactant can be set in the reaction cell in a state where impurities of the reactant are released, and the reaction can be continued for a long time. . When such a reaction cell 1 is heated to 500 to 600 ° C. or higher, low-order iron oxides are formed on the inner wall of the reaction cell 1 and the inner wall of the reactant receiver 4. Since it has been found that this low-order iron oxide has a water-decomposing action, it is conceivable that an object to which the low-order iron oxide is attached is formed in advance and accommodated in the reaction cell 1.

  That is, a low-order iron oxide film forming apparatus 50 as shown in FIG. 5 is prepared, and a high-order iron oxide film forming plate is produced here.

  The apparatus 50 includes a reactive agent processing unit 51 that removes impurities from the reactive agent, and a low-order iron oxide film forming unit 52 that adheres the reactive agent processed here to a plate.

The processing section 51 and the forming section 52 are both in a vacuum atmosphere, and the processing section 51 is provided with a heating kettle 53 in which the reactant is heated and melted. The melted reactant is made of stainless steel (SUS 304). The containers 54 and 54 to 54 are received in the heating furnace 55 provided in the forming unit 52 by opening the vacuum valve 55 provided between the processing unit 51 and the forming unit 52. And placed at the bottom. The inner wall of the heating furnace 55 is covered with a stainless steel plate (SUS304), and an open / close door 56 is attached to the front side thereof. In the central space of the heating furnace 55, a large number of stainless steel (SUS304) attachment plates 57, 57... 57 are set with appropriate vertical and horizontal spacing, and the heating furnace 55 is heated to 500 to 600 ° C. As a result, fine particles are scattered from the molten salt of the reactant in the receiving container 54 into the furnace, and a low-order iron oxide film (NaFeO ₂ , Na ₂ Fe ₅ O ₂ ) is formed on the surface of the adhesion plate 57. If this high-order iron oxide film forming plate 60 (FIG. 6) is simply stored in the reaction cell 1 and water or water vapor is supplied to the water receiver 2a through the water supply port 2 as shown in FIG. In the atmosphere (Fe, Cr, Ni), the surface of the forming plate 60 and the surface of the adhesion plate 57 and the inner wall of the reaction cell 1 are caused by the reaction of the low-order iron oxide fine particles P2 scattered from the surface and the water vapor. High-order iron oxide films (Na ₃ Fe ₅ O ₉ , Na ₈ Fe ₂ O ₇ ) develop and water vapor is decomposed to generate hydrogen. When the high-order iron oxide film becomes a certain thickness, it peels off from the adhesion plate 57 and the inner wall of the reaction cell 1, and a new film is formed inside the old film.

  This technology can be applied to hydrogen stations that require hydrogen on-site, hydrogen power generation, etc.

DESCRIPTION OF SYMBOLS 1 ... Reaction cell 3 ... Reactant receiving 5 ... Reactant 6 ... Heating device 10 ... 1st vacuum vessel 11 ... Heating pot 30 ... Argon box 41 ... 2nd vacuum vessel 50 ... Low iron oxide film formation apparatus 51 ... Reactant Processing part 52 ... Low iron oxide film forming part 57 ... Adhering plate 60 ... Low iron oxide film formation

Claims (2)

A pretreatment method for a reactant in a hydrogen generator that collects hydrogen from water by storing a low-order iron oxide film in a stainless steel reaction vessel as a reactant and bringing the steam and iron oxide film into contact with each other while heating. In this case, sodium hydroxide (NaOH ) is heated to a melting point or higher in an oxygen-free atmosphere to be melted, and a predetermined amount of the melt is poured into a receiving container in the oxygen-free atmosphere, and the receiving container is covered with a stainless steel plate. An iron oxide film made of low-order NaFeO ₂ or Na ₂ Fe ₅ O ₂ is formed on a low-order iron oxide film forming plate disposed in the heating container by heating in a heated oxygen-free atmosphere. Thus, a pretreatment method for a reactant in a hydrogen generator in which a low-order iron oxide film forming plate on which an iron oxide film is formed is housed in a reaction vessel.   The method for pretreating a reactant in a hydrogen generator according to claim 1, wherein the receiving container is SUS304 having a component of 18Cr-8Ni-74Fe.

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