JP6330715B2 - Hydrogen gas generation method - Google Patents

Description

  The present invention relates to a method for producing hydrogen gas, and more particularly, to a simple and convenient method for producing hydrogen gas that can efficiently produce a large amount of hydrogen gas using an iron-based material as a raw material.

  In recent years, reduction of carbon dioxide emission has been demanded from the viewpoint of conservation of the global environment, and development of fuel cells using hydrogen gas has been promoted for automobiles and households. However, securing hydrogen gas stably involves considerable difficulty. At present, hydrogen gas can be produced by methods such as electrolysis of water, reforming of natural gas, and separation of hydrogen from coke reducing gas generated at steelworks. However, the method of electrolysis of water or the method of reforming natural gas consumes a large amount of energy to obtain hydrogen gas, and remains a problem from the viewpoint of conservation of the global environment.

  In addition, the method of separating hydrogen from coke reducing gas generated at steelworks consumes energy for in-house power generation within the steelworks, destroying the energy supply-demand balance within the steelworks, and inadequate energy for in-house power generation. . This causes a contradiction that power is to be purchased from outside.

  Also, in the method of obtaining hydrogen gas by reforming from natural gas, the sum of the energy that produces hydrogen based on natural gas and the energy that can be obtained from the fuel cell by burning the hydrogen is simply burning natural gas. It is said that it is lower than the energy obtained.

  Recently, various hydrogen gas production methods different from the above-described methods have been proposed. For example, Patent Document 1 proposes a method for producing hydrogen from resin waste. In the technique described in Patent Document 1, when a waste containing resin and water are reacted in the presence of hydrous iron oxide particles and / or iron oxide particles, hydrous iron oxide particles and / or iron oxide particles are reacted. It is characterized in that the resin composition contained and the waste containing the resin are mixed, preferably melt mixed and reacted. In the technique described in Patent Document 1, the hydrous iron oxide is one or more of goethite (α-FeOOH), levidcrosite (γ-FeOOH), and δ-FeOOH. It is said that it is preferable. According to the technique described in Patent Document 1, it is said that polymer waste materials that are in need of treatment as waste can be recycled and effectively used.

  However, the technique described in Patent Document 1 is intended for effective utilization of waste containing resin, and includes a resin composition containing hydrous iron oxide particles and / or iron oxide particles, and a resin. When mixing with the waste to be used, it is necessary to keep at a high temperature of 300 to 2000 ° C., and there is a problem that a large amount of energy is consumed. Further, in the technique described in Patent Document 1, the main body of hydrogen generation is a polymer waste material, and the iron oxide particles are supposed to act as a catalyst.

  Patent Document 2 describes a hydrogen gas production method. In the technique described in Patent Document 2, metallic iron is immersed in an electrolytic aqueous solution in a container containing a gas containing an electrolytic aqueous solution and oxygen gas, and iron ions are dissolved from the metallic iron and precipitated as a corrosion product. This is a method for producing hydrogen gas by generating hydrogen gas. According to the technique described in Patent Document 2, seawater can be used as the electrolyte aqueous solution, and simple operation at a relatively low temperature of about 100 ° C. is possible. In the technique described in Patent Document 2, hydrogen is generated because metallic iron is mainly changed into a corrosion product such as iron oxyhydroxide by corrosion.

  According to the technique described in Patent Document 2, hydrogen gas can be produced by operation at a relatively low temperature. However, in the technique described in Patent Document 2, the hydrogen generation source is only Fe, and the corrosion reaction occurs. Based on this, hydrogen gas is generated. Such a phenomenon should have already been observed in the natural world, for example, the generation of hydrogen gas in iron submerged in seawater, but there is no such report, and before operating on an industrial scale, There is a problem that requires further examination.

  Patent Document 3 describes a hydrogen generation method in which hydrogen is generated by mixing exothermic compositions containing water and a water retention agent that generate heat upon contact with oxygen and aluminum particles in the presence of oxygen. According to the technique described in Patent Document 3, hydrogen gas can be generated rapidly and stably by self-heating, temperature control is unnecessary, and it is useful for an apparatus for supplying hydrogen to a fuel cell.

  However, the technique described in Patent Document 3 uses a heat-generating composition and aluminum particles used in a warmer or the like, both of which are expensive and need to be further studied before implementation on an industrial scale. There is a problem of need.

In response to such a problem, some of the present inventors have proposed a hydrogen gas generation method using rust as a material in Patent Document 4. The technique described in Patent Document 4 generates hydrogen gas by performing a process of changing FeOOH to Fe ₂ O ₃ on a material containing FeOOH, preferably a process of heating to a temperature in the range of 100 to 400 ° C. Is the method. According to the technique described in Patent Document 4, hydrogen gas can be easily generated without using an expensive material.

JP 2003-119474 A JP 2006-45033 A JP 2006-240931 A JP 2013-53060 A

  However, the technique described in Patent Document 4 has a problem that the generation efficiency of hydrogen gas is low.

  An object of the present invention is to solve the problems of the prior art and to provide a hydrogen gas generation method capable of generating a large amount of hydrogen gas simply and efficiently without using expensive materials.

In order to achieve the above-mentioned object, the present inventors diligently studied various factors that affect the amount of hydrogen gas to be generated in the technology for generating hydrogen gas using a material containing FeOOH. As a result, the present inventors have found that the amount of hydrogen produced is significantly increased by performing a process of changing FeOOH to Fe ₂ O ₃ in a state where FeOOH as a raw material coexists with a material containing Fe. The “material containing Fe” here is not “Fe” fixed as a compound such as an oxide, but Fe that is in a free state as an alloy element or as an impurity element (hereinafter referred to as “free Fe”). Also referred to as a material). Examples of such “materials containing Fe” include steel materials such as plates, powders, flakes, and wires, that is, steel plates, iron powder, iron wires, steel wires, and the like. In addition, steel materials with iron rust formed on the surface, iron ore that is iron oxide, and iron rust powder can also be used when the oxide is reduced and free Fe is formed on the surface. Corresponds to the “material containing Fe” in the present invention.

  First, the experimental results on which the present invention is based will be described.

  As a material containing FeOOH, use a reagent (powder) of iron rust FeOOH, put the reagent (powder) in a semi-cylindrical board-like container (made of quartz glass), approximately 0.182g (for a full glass), In the gas chromatography, pure argon gas is heated in a non-oxidizing atmosphere under a constant flow rate controlled by a mass flow meter from room temperature to 800 ° C at a heating rate of 200 ° C / h. Measured (Test No. A). During the heat treatment, the amount of hydrogen generated was measured by gas chromatography at intervals of 2.5 min. The gas chromatography detector used was TCD (Thermo-Conductivity-Detector).

  In addition, in the gas chromatography, together with a quartz glass container containing approximately 0.271 g of iron rust FeOOH reagent (powder), on the downstream side of the atmosphere gas flow of the quartz glass container, a cold-rolled steel plate (size: thickness A board-like quartz glass container containing one sheet was placed and the same measurement was performed (test No. B). For comparison, only a board-shaped quartz glass container with a cold-rolled steel plate (size: thickness 0.8 mm x width 10 mm x length 50 mm, mass: 6.42 g) in the gas chromatography. And the same measurement was performed (Test No. C).

  The obtained results are shown in FIG. In addition, the vertical axis | shaft of FIG. 1 is a hydrogen gas generation speed.

  Figure 1 shows the total amount (integrated value) of the generated hydrogen gas. Table 1 shows the amount of iron rust FeOOH (raw material) before heat treatment per mass ppm (total mass of generated hydrogen (mass ppm)). Shown in The total amount of generated hydrogen gas can be obtained by integrating the hydrogen gas generation rate shown in FIG. 1 in time units. In Test No. C, iron rust FeOOH (material) was not charged, so the total amount of generated hydrogen was replaced by cold-rolled steel sheet instead of per mass ppm of iron rust FeOOH (material) before heat treatment. It is displayed per mass ppm.

  From FIG. 1, it is possible to generate hydrogen gas by heating the iron rust FeOOH reagent (powder) (material containing FeOOH) to a temperature in the range of 100 to 500 ° C or 100 to 800 ° C. Yes (test No. A). Further, when the iron rust FeOOH reagent (powder) is subjected to the above heat treatment in the presence of a cold-rolled steel sheet (test No. B), the peak value of the hydrogen gas generation rate is 1.5 as shown in FIG. As shown in Table 1, the total amount of hydrogen gas generated in the temperature range of 100 to 500 ° C is about 2.3 times compared to the case of iron rust FeOOH reagent (powder) only (test No. A). It can be seen that the amount of generated hydrogen increases significantly. In Test No. C, the amount of generated hydrogen was 0.02 ppm by mass, and it can be seen that almost no hydrogen was generated from the cold-rolled steel sheet alone.

Although this specific mechanism is not clear at present, when iron rust FeOOH is heat-treated in the presence of cold-rolled steel sheet, that is, iron (Fe) in a free state, FeOOH becomes Fe. With the change to ₂ O ₃ , in addition to the phenomenon that hydrogen is generated, the amount of generated hydrogen gas is remarkably increased by the action of reducing water by iron (Fe) in a free state and the overlapping action thereof. The present inventors consider.

  Furthermore, the treatment for heating the iron rust FeOOH was performed in the same manner using iron powder instead of the cold-rolled steel sheet, and the amount of hydrogen generated was measured. In addition, atomized iron powder and reduced iron powder were used as the iron powder. The reduced iron powder is an aggregate of particles exhibiting a porous shape. The test conditions were as follows.

  Test No. D consists of a quartz glass container containing approximately 0.251 g of iron rust FeOOH reagent (powder) in the gas chromatography, and an atomized iron powder (on the downstream side of the atmosphere gas flow of the quartz glass container ( A board-shaped quartz glass container with a mass of 3.53 g) was placed, and a heating treatment was performed by heating from room temperature to 800 ° C. at a heating rate of 200 ° C./h. During the heat treatment, the amount of generated hydrogen was similarly measured by gas chromatography at intervals of 2.5 min. Similarly, the gas chromatograph detector used TCD (Thermo-Conductivity-Detector).

  Test No. E is a quartz glass container containing approximately 0.127 g of iron rust FeOOH reagent (powder) and atomized iron powder (mass: 2.08 g). A similar heat treatment was performed in a non-oxidizing atmosphere under a constant flow rate where the gas was controlled by a mass flow meter, and the amount of generated hydrogen was measured.

  Test No. F is a quartz glass container containing only atomized iron powder (mass: 3.70 g) in a gas chromatograph and in a non-oxidizing atmosphere under a constant flow rate with pure argon gas controlled by a mass flow meter. The same heat treatment was performed, and the amount of generated hydrogen was measured in the same manner. In Test No. F, iron rust FeOOH (material) was not charged, so the total amount of generated hydrogen was replaced with iron powder (ppm) of mass of iron rust FeOOH (material) before heat treatment. It is displayed per mass ppm of atomized iron powder.

  The obtained results are shown in FIG.

  Next, instead of atomized iron powder, reduced iron powder was used, and the same heat treatment was performed.

  Test No. G consists of a quartz glass container containing approximately 0.254 g of iron rust FeOOH reagent (powder) in the gas chromatography and a reduced iron powder (on the downstream side of the atmospheric gas flow in the quartz glass container. A board-shaped quartz glass container with a mass of 3.20 g) was placed and subjected to a heat treatment of heating from room temperature to 800 ° C. at a heating rate of 200 ° C./h. During the heat treatment, the amount of generated hydrogen was similarly measured by gas chromatography at intervals of 2.5 min. Similarly, the gas chromatograph detector used TCD (Thermo-Conductivity-Detector).

  Test No. H is a quartz glass container containing approximately 0.148 g of iron rust FeOOH reagent (powder) mixed with reduced iron powder (mass: 2.16 g). A similar heat treatment was performed in a non-oxidizing atmosphere under a constant flow rate where the gas was controlled by a mass flow meter, and the amount of hydrogen generated was measured.

  Test No. I is a quartz glass container containing only reduced iron powder (mass: 3.13 g) in a non-oxidizing atmosphere under a constant flow rate in a gas chromatography and pure argon gas controlled by a mass flow meter. The same heat treatment was performed, and the amount of generated hydrogen was measured. In Test No. I, since iron rust FeOOH (material) was not charged, the total amount of generated hydrogen was changed to iron powder (ppm) instead of per mass ppm of iron rust FeOOH (material) before heat treatment. It is displayed per mass ppm of (reduced iron powder).

  The obtained results are shown in FIG.

  From Figs. 2 and 3, the iron rust FeOOH reagent (powder) is subjected to heat treatment together with iron powder (test No. D, No. E; No. G, No. H). Compared to the case of powder) alone (Fig. 1 Test No. A), there are multiple peaks of hydrogen gas generation rate, and the peak value of hydrogen gas generation rate around 300 ° C is compared. Found to be higher. In addition, when the iron rust FeOOH reagent (powder) is heat-treated together with the iron powder, the iron rust FeOOH reagent (powder) and the iron powder are put in separate containers and processed (test No. D, No. G) is more hydrogen generated than when iron rust FeOOH reagent (powder) and iron powder are mixed (in contact with each other) and processed in the same container (test No. E, No. H). I found that the amount was large. In addition, when the heat treatment was performed using iron powder alone (Test No. F; No. I), the amount of generated hydrogen was extremely small.

  Similar to Fig. 1, the total amount of hydrogen gas generated (integrated value) is obtained from Figs. 2 and 3, and the amount of iron rust FeOOH (material) before heat treatment per mass ppm (total amount of hydrogen generated) The mass (mass ppm) is shown in Table 2. Since there are a plurality of hydrogen gas generation rate peaks, Table 2 shows the total amount in each temperature range by dividing the temperature range into 2-3 intervals. When the hydrogen gas generation rate had one peak, the temperature range was RT to 500 ° C.

  From Table 2, when the iron powder used with the iron rust FeOOH reagent (powder) is reduced iron powder during the heat treatment, the amount of hydrogen generated is significantly greater than when atomized iron powder is used ( It was found that the total amount of generated hydrogen increased by about 1.5 times. The reason for this is not completely clear at present, but the present inventors presume that the reduced iron powder is caused by the porous and large surface area.

The present invention has been completed based on such findings and further studies. That is, the gist of the present invention is as follows.
(1) When a material containing FeOOH is subjected to a treatment in which the FeOOH is changed to Fe ₂ O ₃ to generate hydrogen gas, the material and the material containing Fe coexist, and the material containing Fe is A hydrogen gas generating method, wherein the material is disposed so that the mass ratio with respect to the amount of FeOOH contained in the material is 0.5 or more in terms of free Fe, and the process of changing the FeOOH to Fe ₂ O ₃ is performed.
(2) Arrange a material containing FeOOH and a material containing Fe so that the material containing Fe is 0.5 or more in terms of free Fe in terms of mass ratio to the amount of FeOOH contained in the material. The FeOOH was changed to Fe ₂ O ₃ to generate hydrogen gas, and then the rust treatment was performed to change the Fe ₂ O ₃ to FeOOH. The treatment in which the FeOOH is changed to Fe ₂ O ₃ coexists with the FeOOH produced by the rust treatment and the material containing Fe, and the material containing Fe is subjected to the rust treatment. A method for generating hydrogen gas, characterized in that the step of generating hydrogen gas is repeated a plurality of times in a mass ratio with respect to the amount of generated FeOOH so as to be 0.5 or more in terms of free Fe.
(3) Hydrogen gas characterized in that, in (1) or (2), the coexisting Fe-containing material is arranged so that the mass ratio to the FeOOH amount is 1.0 or more in terms of free Fe Generation method.
(4) The hydrogen gas according to any one of (1) to (3), wherein the co-existing Fe-containing material is in the form of a plate, a powder, a chip, or a line. Generation method.
(5) In any one of (1) to (4), the treatment in which the FeOOH is changed to Fe ₂ O ₃ heats the raw material containing FeOOH and the material containing Fe to a temperature in the range of 100 to 600 ° C. A method for generating hydrogen gas, characterized in that:
(6) The method for generating hydrogen gas according to any one of (1) to (5), wherein the material containing FeOOH is an iron-based material containing FeOOH.
(7) The hydrogen gas generation method according to any one of (1) to (6), wherein the process of changing FeOOH to Fe ₂ O ₃ is a process performed in a non-oxidizing atmosphere.

  According to the present invention, a large amount of hydrogen gas can be generated in a simple and efficient manner without using an expensive material, and a remarkable industrial effect can be achieved.

It is a graph which shows the relationship between the hydrogen generation speed using a reagent (iron rust component), and heating temperature. It is a graph which shows the relationship between the hydrogen generation rate using a reagent (iron rust component) and heating temperature in the presence of atomized iron powder. It is a graph which shows the influence of iron powder on the relationship between the hydrogen generation rate using a reagent (iron rust component) and heating temperature in the presence of reduced iron powder.

In the present invention, when a material containing FeOOH is subjected to a treatment in which FeOOH is changed to Fe ₂ O ₃ and hydrogen gas is generated, the treatment in which this FeOOH is changed to Fe ₂ O ₃ is performed together with the material containing Fe. Apply. The “material containing Fe” here is a material containing free Fe that is not fixed as a compound.

  In the present invention, a material containing FeOOH is used as a hydrogen generation source.

The “material containing FeOOH” herein may be any material containing FeOOH, and the type and form thereof are not particularly limited. In addition, FeOOH has known α phase, β phase, and γ phase, and among them, the existence probability of α phase is high, but in the present invention, any phase can be used as a hydrogen gas generation source. The difference does not matter. Further, “FeOOH” here is equivalent to a substance represented as “Fe ₂ O ₃ .H ₂ O”.

  Examples of the material containing FeOOH include pure FeOOH powder and iron-based materials such as steel materials in which FeOOH is formed as rust. The steel material may be any composition that can form FeOOH, which is the main component of red rust, and various steel materials and various iron scraps can be applied, and the composition is not particularly limited. Examples of the iron-based material further include an Fe-based alloy, an alloy containing Fe, and iron ore. Further, from the viewpoint of easy reaction, the material is preferably finely cut into powder, chips, or flakes.

In the present invention, the material containing FeOOH is hydrogen source, subjected to the treatment FeOOH is changed to Fe ₂ O _3.

As a process for changing FeOOH to Fe ₂ O ₃ , a material containing FeOOH is heated to a temperature range of 100 to 600 ° C. If a material containing FeOOH is heated in this temperature range, the details of the reaction are not clear, but hydrogen gas is generated by a reaction in which FeOOH changes to Fe ₂ O ₃ . In addition, the temperature range to heat becomes like this. Preferably it is a temperature range of 100-500 degreeC, More preferably, it is a temperature range of 250-400 degreeC.

  As the process of heating to the temperature range of the above range, the process of heating and holding at a constant temperature of the above range (constant temperature heating), or the temperature range of the above range at a predetermined heating rate (heating) Either of the processing (continuous heating) to perform may be sufficient.

The material is heated in a non- oxidizing atmosphere, and more preferably in a container having a non-oxidizing atmosphere. The non-oxidizing atmosphere is preferably an inert atmosphere such as pure argon, but is not limited thereto. The heat source for heating is not particularly limited, and any conventional heating means such as a heater and a burner can be applied.

  Note that the amount of hydrogen generated depends on the amount of FeOOH contained in the material. For this reason, it is preferable to supply the raw material containing FeOOH continuously or intermittently (batch type) so as to obtain a desired hydrogen gas generation amount.

In the present invention, when a material containing FeOOH is subjected to a process of changing FeOOH to Fe ₂ O ₃ , the “material containing Fe” is present in the same atmosphere (coexistence). The “material containing Fe” here refers to a material containing free “Fe” as an alloy element or impurity element, not “Fe” fixed as a compound such as an oxide. For example, Fe contained in a Ni-based alloy or Fe in a Fe-based alloy such as a stainless steel material is free Fe, but Fe in Fe ₂ O ₃ is not free Fe. And in this invention, it arrange | positions so that "material containing Fe" may be 0.5 or more in conversion of free Fe (mass) by mass ratio with respect to the amount (mass) of FeOOH contained in a raw material.

In the present invention, such a “material containing Fe” is made to coexist with a material containing FeOOH, assuming that FeOOH changes to Fe ₂ O ₃ and promotes the reaction of generating hydrogen gas. The mechanism that promotes the reaction of generating hydrogen gas by coexisting the above-mentioned “material containing Fe” with a material containing FeOOH has not been clarified so far. I think as follows.

The reaction in which FeOOH is changed to Fe ₂ O ₃ and hydrogen gas is generated has not been clarified so far, but the present inventors presume as follows.

When FeOOH changes to Fe ₂ O ₃ , the following formula (1)
2FeOOH → Fe ₂ O ₃ + H ₂ + 1 / 2O ₂ (1)
Hydrogen gas is generated by the direct reaction shown in the following, or the following equation (2)
2FeOOH → Fe ₂ O ₃ + H ₂ O (2)
A part of the water H ₂ O formed in the reaction represented by
H ₂ O → H ₂ + 1 / 2O ₂ (2a)
It can be presumed that hydrogen gas is generated by dissociation by the reaction shown in FIG. In the reactions represented by the formulas (1), (2), and (2a), both hydrogen gas H ₂ and oxygen gas O ₂ are generated, but the generated oxygen gas O ₂ is a large amount of iron. It is presumed that only the generated hydrogen gas H ₂ was detected without being absorbed outside by the rust.

  By coexisting “materials containing Fe” with materials containing FeOOH, a certain type of catalytic action works, and the reactions shown in the above formulas (1), (2), and (2a) are promoted. It is guessed.

Or, further, when FeOOH changes to Fe ₂ O ₃ ,
2FeOOH → Fe ₂ O ₃ + H ₂ O (2)
In the case where water H ₂ O is formed by the reaction represented by the following formula (3),
_{2Fe + 3H 2 O → Fe 2} O 3 + 3H 2 ...... (3)
It is estimated that the reaction in which water is reduced and hydrogen gas H ₂ is generated proceeds.

  Thus, in addition to coexisting the “material containing Fe” with the material containing FeOOH, the reactions shown in the above formulas (1), (2), and (2a) are promoted. Further, it is presumed that the amount of hydrogen gas generated is increased as compared with the case where the “materials containing Fe” do not coexist because the reactions shown by the equations (2) and (3) overlap.

  The “Fe-containing material” to be coexisted is arranged so that the mass ratio with respect to the amount (mass) of FeOOH contained in the material is 0.5 or more in terms of free Fe. The “material containing Fe” that coexists with the material in the present invention may be any material containing free Fe, and the type and shape thereof need not be limited. However, if the “material containing Fe” is less than 0.5 in terms of the mass ratio of FeOOH (mass) contained in the raw material in terms of free Fe, the above-mentioned certain catalytic action and water reducing action will decrease. Conceivable.

  Further, when the contained Fe is fixed as an oxide or other compound, the above-described action cannot be expected. For this reason, in the “material containing Fe”, it is necessary to use a material containing Fe (free Fe) in a state where it can act as free Fe.

  As used herein, “Fe-containing material” includes iron plate, iron alloy plate, iron plate material such as steel plate, or iron powder such as iron powder, steel powder, alloy steel powder, or iron wire, steel. Examples thereof include iron-based materials such as iron-based linear materials such as wires and wire wool, iron-based chip materials such as shavings such as steel materials, and iron-based flake materials. In iron-based materials, there may be a difference in free Fe content depending on the alloy element content, impurity element content, etc., but usually contains 90% or more of free Fe by mass%. Therefore, in many iron-based materials, the mass can be almost the mass corresponding to the amount of FeOOH contained in the material. In addition, in the high alloy steel containing a large amount of Cr, Mo, Ni, etc. like stainless steel, the amount of the alloying element to be contained is large, but the balance is Fe, and the balance Fe is obtained by subtracting the amount of alloying elements contained. It goes without saying that the mass of is the mass of free Fe corresponding to the amount of FeOOH contained in the material. Further, in the Ni-base alloy and the Co-base alloy, the Fe content is small, and the Fe content is the mass of free Fe corresponding to the FeOOH amount contained in the material.

  In addition, steel sheets (steel materials) with a thick coating on the surface such as plating, steel sheets (steel materials) with an oxide film formed thick on the surface, iron ore, etc. are unlikely to expose Fe on the surface, In many cases, it does not correspond to the “material containing Fe” in the present invention. In addition, when the film or oxide film formed on the surface is reduced by the generated hydrogen gas and free Fe can be exposed on the surface, it corresponds to the “material containing Fe” in the present invention. There are cases where it can be considered. For example, it is confirmed that there is no problem as a “material containing Fe” in the present invention for a plated steel plate that has been pressed into a scrap and exposed to a base steel plate, or a stainless steel material having a thin passive film on the surface. doing. Even in iron ore, when the amount of hydrogen generation is large, the surface may be reduced and free Fe may be exposed on the surface, and it may be considered that it corresponds to the “material containing Fe” in the present invention. .

  In addition, the “material containing Fe” in the present invention should have a large surface area in order to promote the reaction, and is preferably a thin material, a linear material, a chip-shaped material, a powder, or the like.

It is preferable that the “material containing Fe” be arranged in the presence of an amount (mass) corresponding to the amount (mass) of FeOOH contained in the raw material that is a hydrogen generation source. The “material containing Fe” is coexistingly arranged so that the mass ratio with respect to the amount (mass) of FeOOH contained in the material is 0.5 or more, preferably 1.0 (equivalent) or more in terms of free Fe. If the “material containing Fe” is less than 0.5 by mass ratio with respect to the amount of FeOOH contained in the material (mass), the so-called catalytic action and water reduction action are reduced, and the desired amount of hydrogen gas generated Cannot be secured. For this reason, the “Fe-containing material” that coexists with the FeOOH-containing material is expressed by the following formula (Fe-containing mass (g) in terms of free Fe) / (FeOOH content (mass) (g) in the material)
The ratio (mass ratio) defined in the above was determined to be 0.5 or more. The upper limit of the ratio is not particularly limited, but when the ratio exceeds 10 and the amount of “material containing Fe” is increased, the effect tends to be saturated.

  In order to promote the reaction, it is preferable that the “material containing Fe” be disposed in the vicinity of the material containing FeOOH. In addition, the “material containing Fe” and the material containing FeOOH may be mixed and arranged, but the material containing FeOOH and the “material containing Fe” are preferably put in separate containers, preferably FeOOH. From the viewpoint of the amount of generated hydrogen, it is preferable to dispose the gas at a downstream side of the atmosphere gas flow of the container containing the raw material containing. When the “material containing Fe” and the material containing FeOOH are mixed and brought into contact with each other, the amount of hydrogen gas generated is reduced. For this reason, it is preferable to perform the heat treatment without bringing the material containing FeOOH into contact with the “material containing Fe”.

As described above, the coexistence of the material containing FeOOH and the “material containing Fe” promotes the reaction of generating hydrogen gas. However, the reaction in which the generated Fe ₂ O ₃ is reduced by the generated hydrogen gas, that is, the following formula
3Fe ₂ O ₃ + H ₂ → 2Fe ₃ O ₄ + H ₂ O (3)
Or even
2Fe ₃ O ₄ + 2H ₂ → 6FeO + 2H ₂ O (4)
It is estimated that the generated hydrogen gas is consumed. For this reason, the amount of hydrogen gas obtained will decrease. Although some of the generated water may contribute again to the generation of hydrogen gas, all the generated water is not used for hydrogen gas generation.

For this reason, when the “material containing Fe” and the material containing FeOOH are mixed and arranged, the generated hydrogen gas passes through the region where Fe ₂ O ₃ is densely present, and is described above. The reaction (3) and further the reaction (4) occur, and the amount of hydrogen gas obtained is reduced. For this reason, in the present invention, the “material containing Fe” and the material containing FeOOH are preferably placed in separate containers and preferably arranged downstream of the atmospheric gas flow in the container containing the material containing FeOOH. It is preferable.

Further, in the present invention, as described above, after the material containing FeOOH is subjected to the treatment of changing FeOOH to Fe ₂ O ₃ in the presence of the “material containing Fe” and hydrogen gas is generated, A rust treatment is performed to change the Fe ₂ O ₃ to FeOOH, and then a treatment in which the FeOOH generated by the rust treatment is changed to Fe ₂ O ₃ is performed in the coexistence of the “material containing Fe”, It is preferable to set it as the process to generate. It is more preferable to perform such a process several times.

Here, “rust treatment” means treatment for changing Fe ₂ O ₃ to FeOOH, and means treatment for changing Fe ₂ O ₃ , which is a residue from which hydrogen gas has been generated, to rust again and changing to FeOOH. The conditions of the rust treatment are not particularly limited as long as the treatment can change Fe ₂ O ₃ to FeOOH. However, as an easy method, for example, first, water is allowed to come into contact with air in a room temperature air atmosphere. The method of applying or the method of spraying with water is mentioned. Further, in a humid atmosphere with a humidity of 50% or more, preferably in a temperature range of 100 ° C. or less, an appropriate range varies depending on the weight, volume, and surface area of the material, but a treatment for holding for 30 minutes or more is preferable. When the temperature exceeds 100 ° C., hydrogen generation becomes remarkable, FeOOH changes to Fe ₂ O _3, and FeOOH cannot be formed.

The rust treatment as described above is performed to change Fe ₂ O ₃ , which is a residue that generates hydrogen gas, to FeOOH. Then, the resulting FeOOH, a process of further changes to Fe ₂ O ₃ in the presence of "material containing Fe", if Hodokose the process of changing the FeOOH to Fe ₂ O _3, further generates a large amount of hydrogen gas Can be made. If such a process is repeated a plurality of times, the yield of hydrogen gas per amount of the same material can be increased.

  If the above-mentioned process is repeated multiple times, the "material containing Fe" coexisting with the material containing FeOOH can be used multiple times unless mixed with the material containing FeOOH. It is. Needless to say, the “material containing Fe” that coexists with the material does not undergo rust treatment. Needless to say, the “material containing Fe” has a larger surface area.

  Hereinafter, the present invention will be described based on examples.

Example 1
0.25g of iron rust FeOOH reagent (powder) in a semi-cylindrical, board-like container (made of quartz glass) (filled with a container), and pure argon gas was controlled with a mass flow meter in gas chromatography. Under a flow rate, heat treatment was performed by heating from room temperature to 600 ° C. at a heating rate of 200 ° C./h, and it was set as test No. 1 (comparative example), which was a standard.

Similarly, 0.31 g of iron rust Fe ₂ O ₃ reagent (powder) is put in a semi-cylindrical board-like container (made of quartz glass), and heat-treated in the same manner, and test No. 2 (comparison) Example). The material after the heat treatment was used as a raw material, and the same heat treatment as in Test No. 2 was performed to obtain Test No. 2A (Comparative Example).

  In addition, a semi-cylindrical, board-like container (quartz glass) containing 0.19 to 0.31 g of iron rust FeOOH reagent (powder) in a gas chromatograph at a constant flow rate with pure argon gas controlled by a mass flow meter. ) And a cold-rolled steel sheet (sheet thickness: 0.8 mm) that is changed in the range of 0.03 to 15.87 g in terms of free Fe (mass) as “Fe-containing material” on the downstream side of the atmospheric gas of the container ), And heat treatment was performed by heating from room temperature to 600 ° C. (partially 800 ° C.) at a heating rate of 200 ° C./h to obtain Test Nos. 3 to 9. In addition, the mass ratio (= (free Fe amount (mass)) of the amount of free Fe (free Fe equivalent mass) in the “materials containing Fe” coexisting with the FeOOH amount (mass) contained in the material ) / FeOOH amount (mass)) was calculated and shown in Table 3.

  In test No. 8 (example of the present invention), a cold-rolled steel sheet as a “material containing Fe” was placed in contact with a reagent (powder) of iron rust FeOOH, and was similarly heat-treated. . In test No. 9 (example of the present invention), a cold-rolled steel sheet was placed so as to cover a semi-cylindrical board-like container containing a reagent (powder) of iron rust FeOOH, and was similarly heat-treated. .

In addition, a semi-cylindrical board-shaped container (made of quartz glass) containing a reagent (powder) of iron rust FeOOH under a constant flow rate controlled with a mass flow meter in pure gas in a gas chromatography, A semi-cylindrical board-like container (made of quartz glass) containing an iron-rust Fe ₂ O ₃ reagent (purity: 99% or more; powder) instead of cold-rolled steel sheet on the downstream side of the atmospheric gas of the container And heat-treated in the same manner as test No. 10 (comparative example). Note that the iron rust Fe ₂ O ₃ is fixed to oxygen O and does not correspond to the “material containing Fe” in the present invention.

  In addition, as a material containing FeOOH, instead of the iron rust FeOOH reagent (powder), a cold rolled steel sheet is used as a material containing FeOOH, which has been subjected to repeated wet and dry treatment to form rust (FeOOH) on the surface. A cold-rolled steel plate (“Fe-containing material”) having substantially the same mass was coexisting on the downstream side, and the same heat treatment was performed to obtain Test No. 12 (Example of the present invention). In addition, the same heat treatment was performed without arranging the “material containing Fe”, and Test No. 11 (Comparative Example) was obtained.

  In any case, the amount of hydrogen generated in each test was analyzed using gas chromatography at 2.5 min intervals while heat treatment was performed, the temperature-hydrogen generation rate spectrum was obtained, and the amount of generated hydrogen was calculated. The amount of hydrogen generated was determined by integrating the hydrogen generation rate in time units. The gas chromatography detector used was TCD (Thermo-Conductivity-Detector).

  The total amount (integrated value) of the obtained hydrogen gas is shown in Table 3 as the amount of iron rust FeOOH (material) before heat treatment per mass ppm (total mass of generated hydrogen (mass ppm)). The total amount (integrated value) of the generated hydrogen gas was in the temperature range of 150 to 500 ° C. In addition, when generation | occurrence | production of hydrogen gas was seen also in the area | region over 500 degreeC, it computed also about the whole temperature area | region of RT-800 degreeC (some RT-600 degreeC).

  And, from the total amount of generated hydrogen gas obtained in the temperature range of 150-500 ° C, the increase rate of the generated hydrogen gas amount (= (FeOOH (raw material) The amount of generated hydrogen per mass ppm (mass ppm) / (the amount of generated hydrogen per mass ppm of FeOOH (material) of test No. 1 (mass ppm)) was calculated.

  In tests No.11 and No.12, the exact amount of iron rust FeOOH before heat treatment in the material was unknown, so the total amount of generated hydrogen gas was the amount generated per mass ppm of the total material (generated The total amount of hydrogen (mass ppm) is shown in Table 3. Therefore, the increase rate of the generated hydrogen amount in Test No. 12 was set based on the generated hydrogen amount in Test No. 11.

  Each of the examples of the present invention shows a hydrogen gas generation amount that is 1.3 times or more higher than the hydrogen gas generation amount in the test No. 1 as a reference, and together with the material containing FeOOH, “material containing Fe” It can be seen that by coexisting, generation of hydrogen gas is remarkably promoted.

  The amount of “material containing Fe” coexisting with the material containing FeOOH is 0.13 of the amount (mass) of FeOOH contained in the material in terms of free Fe (mass), and the amount of “material containing Fe” is this amount. In test No. 7 (comparative example) that is outside the scope of the invention, the hydrogen gas generation rate is about 1.1 times the hydrogen gas generation rate in test No. 1, which is the standard, and it is said that hydrogen gas generation is significantly accelerated. Hateful.

  In addition, when a material containing FeOOH and a cold-rolled steel sheet that is a “material containing Fe” are brought into contact with each other (test No. 8), hydrogen in test No. 1 where the amount of hydrogen gas generated is the standard. The amount of generated hydrogen gas is 1.3 times the amount of gas generated, and compared with 1.7 times of the case of no contact (test No. 3).

In test No. 10 (comparative example), iron rust Fe ₂ O ₃ coexists with a material containing FeOOH instead of “material containing Fe”, but the same as test No. 1 as a reference. The amount of hydrogen gas generated. This is because, by heating a material containing FeOOH, hydrogen gas is generated in the same manner as in test No. 1, but iron rust Fe ₂ O ₃ does not have an action of promoting hydrogen gas generation. It is thought that the amount of hydrogen gas generated was similar.

  In addition, instead of iron rust FeOOH (powder) as the material, a steel plate with rust FeOOH is used, and a heat treatment is performed by placing “materials containing Fe” (cold rolled steel plate) together with the material (test No. 12) and 1.4 times as much hydrogen gas generation were observed as compared with the case where “Fe-containing material” (cold rolled steel sheet) was not disposed (Test No. 11).

In Test No. 2a, the relationship between the heating temperature and the hydrogen generation rate was almost flat, and the generation of hydrogen gas was slight. This is probably because FeOOH, which is a hydrogen generation source, hardly remains because the material after heat treatment was used as a raw material.
(Example 2)
A semi-cylindrical board-like container (made of quartz glass) containing 0.26-0.31 g of iron rust FeOOH reagent (powder) at a constant flow rate controlled by a mass flow meter with pure argon gas in gas chromatography And a stainless steel wire wool (wire diameter: 0.3 to 0.5 mmφ) having a weight changed in the range of 0.90 to 0.25 g is disposed on the downstream side of the atmospheric gas in the container. From No. to 600 ° C. (partially 800 ° C.), a heat treatment was performed at a heating rate of 200 ° C./h to obtain Test No. 21 ( Reference Example). In addition, a stainless steel wire wool as a “material containing Fe” was placed in contact with the iron rust FeOOH reagent (powder) and heat-treated in the same manner as in test No. 22 ( reference example). did.

  For comparison, only stainless steel wire wool, which is a “material containing Fe”, was placed and subjected to the same heat treatment to obtain Test No. 23 (Comparative Example).

  In any case, in the same manner as in Example 1, the amount of generated hydrogen was analyzed using gas chromatography at 2.5 min intervals while performing heat treatment, and a temperature-hydrogen generation rate spectrum was obtained. Each was calculated. The amount of hydrogen generated was determined by integrating the hydrogen generation rate in time units. The gas chromatography detector used was TCD (Thermo-Conductivity-Detector).

  The total amount (integrated value) of the generated hydrogen gas obtained is shown in Table 4 as the amount of iron rust FeOOH (raw material) before heat treatment per mass ppm (total mass of generated hydrogen (mass ppm)).

  The total amount (integrated value) of the generated hydrogen gas was calculated in the temperature range of 150 to 500 ° C. (partially to 430 ° C.). In addition, when generation | occurrence | production of hydrogen gas was seen also in the area | region over 500 degreeC (some 430 degreeC), it calculated also about RT-800 degreeC whole temperature range.

  Then, from the total amount of generated hydrogen gas of each test No. obtained in the temperature range of 150 to 500 ° C., the generated hydrogen gas based on the total amount of generated hydrogen gas of Test No. 1 obtained in Example 1 is used as a reference. The rate of increase in the amount (= (the amount of hydrogen generated per mass ppm of FeOOH (material) (mass ppm) / (the amount of hydrogen generated per mass ppm of FeOOH (material) of test No. 1) (mass ppm))) did.

All of the reference examples show a hydrogen gas generation rate that is 1.5 times higher than the hydrogen gas generation rate in the standard test No. 1, and together with a material containing FeOOH, stainless steel wire wool coexists. It can be seen that the generation of hydrogen gas is remarkably promoted. A passive film is formed on the surface of the stainless steel wire wool, but it can be seen that a passive film having such a film thickness does not adversely affect the acceleration of the hydrogen gas generation reaction. Stainless steel wire wool corresponds to the “material containing Fe” in the present invention. Note that in test No. 23 in which only the stainless steel wire wool as the “material containing Fe” was placed and subjected to the same heat treatment, hydrogen gas was hardly generated.
(Example 3)
A semi-cylindrical, board-like container (made of quartz glass) containing 0.25 g of iron rust FeOOH reagent (powder) at a constant flow rate controlled by a mass flow meter with pure argon gas in gas chromatography A board-like quartz glass container containing atomized iron powder (mass: 3.25 g) is placed downstream of the atmospheric gas flow of the container, and the heating rate is 200 ° C./h from room temperature to 400 ° C. Heating was performed, and heat treatment was performed for ₂ hours at 400 ° C., and FeOOH was changed to Fe ₂ O ₃ to generate hydrogen gas.

  In the same manner as in Example 1, the amount of released hydrogen was analyzed using gas chromatography at 2.5 minute intervals while performing the heat treatment, and the amount of released hydrogen was calculated. The total amount of hydrogen released by this treatment was 21 ppm by mass.

Next, the residue (Fe ₂ O ₃ ) from which hydrogen is generated is held for 8 hours or more in an atmosphere maintained at a humidity of 50 to 100% in a temperature range of RT to 50 ° C., and subjected to rust treatment to generate rust, FeOOH was generated.

  The obtained FeOOH was heated together with new atomized iron powder (mass: 3.11 g) in a gas chromatography in pure argon atmosphere, further at a heating rate of 200 / h, to a temperature of 400 ° C, and at 400 ° C for 2 hours. The holding heat treatment was performed to release hydrogen. Similarly, the amount of generated hydrogen was measured using gas chromatography. The total amount of hydrogen generated by this treatment was 16.3 ppm by mass.

  The process of sequentially performing each of the above treatments was the first process, and the second process was repeated, and the amount of released hydrogen was measured in the same manner. In the second step, the amount of hydrogen released was 37.3 mass ppm in total. It can be seen that hydrogen can be repeatedly generated by performing the rust treatment.

Claims (5)

The material containing FeOOH is subjected to a treatment in which the FeOOH is changed to Fe ₂ O ₃ to generate hydrogen gas. The material and the material containing Fe are allowed to coexist and the material containing Fe is added to the material. by mass ratio of FeOOH amount contained, and arranged to be free of Fe converted at least 0.5, the FeOOH by heating to a temperature in the range of 100 to 600 ° C. in a non-oxidizing atmosphere Fe ₂ O ₃ A process for generating hydrogen gas, characterized by performing a process that changes to FeOOH coexist and materials including materials and Fe containing and material comprising the Fe is by mass ratio of FeOOH amount contained in the material, arranged so as to be 0.5 or more free Fe terms non The FeOOH is changed to Fe ₂ O ₃ by heating to a temperature in the range of 100 to 600 ° C. in an oxidizing atmosphere to generate hydrogen gas, and then the Fe ₂ O ₃ is changed to FeOOH. A process of changing the FeOOH produced by the rust treatment to Fe ₂ O ₃ by coexisting the FeOOH produced by the rust treatment and a material containing Fe, And, the material containing the Fe is a mass ratio with respect to the amount of the FeOOH generated by the rust treatment, and is disposed and applied so as to be 0.5 or more in terms of free Fe, thereby generating hydrogen gas, A hydrogen gas generation method characterized by being repeated a plurality of times.   The hydrogen gas generation method according to claim 1 or 2, wherein the co-existing Fe-containing material is arranged so that the mass ratio with respect to the FeOOH amount is 1.0 or more in terms of free Fe.   4. The method for generating hydrogen gas according to claim 1, wherein the co-existing Fe-containing material is in a plate shape, a powder shape, a chip shape, or a linear shape. The method for producing hydrogen gas according to any one of claims 1 to 4 , wherein the material containing FeOOH is an iron-based material containing FeOOH.

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