JP4740563B2 - Hydrogen generator - Google Patents

Description

  The present invention relates to a hydrogen generator for supplying hydrogen to a fuel cell or the like.

  A fuel cell using hydrogen as a fuel is generally provided with a hydrogen generator for reforming methanol or the like into hydrogen by a partial oxidation method or a steam reforming method and supplying the reformed fuel to the fuel cell. However, in such a method, carbon monoxide (CO) is by-produced with hydrogen, which poisons the fuel cell electrode. Therefore, it is necessary to remove CO to 10 ppm or less. However, if a CO removing means is installed, there is a problem that the reformer becomes larger and more expensive. In addition, the steam reforming method needs to be heated to a very high temperature of about 800 ° C. However, if an electric heater by resistance heating is used to perform such heating, a large amount of energy is required, which exceeds the power generated by the fuel cell and cannot be established as a fuel cell power generation system.

On the other hand, as a method for generating hydrogen without generating CO or CO ₂ as a by-product, a method using a metal such as iron that chemically reacts with water to generate hydrogen has been proposed (for example, Japanese Patent Application Laid-Open No. 2004-149394). Issue gazette). According to this method, since a metal such as iron may be heated at a temperature of about 600 ° C. or less, it requires less energy than the steam reforming method, but it is desired to construct a system that can further save energy. ing.

JP 2004-149394 A

  In view of the above problems, the present invention provides a hydrogen generator that can stably generate hydrogen without generating carbon monoxide or carbon dioxide as a by-product and without requiring a large amount of electric energy. For the purpose.

In order to achieve the above object, a hydrogen generator according to the present invention includes a reaction vessel provided with a metal container that contains a metal that generates hydrogen by a chemical reaction with water, and water is introduced into the reaction vessel. A water introduction port, a vaporization space portion disposed between the water introduction port and the metal storage portion, evaporating water introduced from the water introduction port and then supplying the water to the metal storage portion, It is installed in the vaporization space, and is connected to the vaporization promotion means for increasing the surface area of water to promote the vaporization of water, and to transfer heat in the reaction vessel to the vaporization promotion means. comprises a heat plate, the vaporizing promoting means is a wick woven from metal fibers, the heat transfer plate is copper, brass, aluminum, Ri Do iron or stainless steel, said metal fibers of copper, brass , Aluminum, iron or stainless steel The wick is welded to a portion of the vaporization space where the surface of the heat transfer plate has been treated to increase the surface area, and the metal storage portion generates heat due to a chemical reaction with oxygen. Metal is also housed, and the heat transfer plate extends in a wave shape inside the metal housing portion from the vaporization promoting means .

Thus, water is decomposed to generate hydrogen by chemical reaction (oxidation) of water and metal (for example, the reaction formula when iron is used as a metal is 3Fe + 4H ₂ O → Fe ₃ O ₄ + 4H ₂ Carbon monoxide (CO), which poisons fuel cell electrodes, is not a by-product. Therefore, it is not necessary to provide CO removing means, and the apparatus can be reduced in size and cost. In addition, since the reaction is performed in the range of room temperature to about 600 ° C., preferably in the range of about 100 ° C. to about 400 ° C., energy consumption can be reduced as compared with the steam reforming reaction at about 800 ° C. .

  Furthermore, since a vaporization promoting means for increasing the surface area of the water and promoting the vaporization of the water is installed in the vaporization space disposed between the water introduction port and the metal storage portion, the vaporization space is formed from the water introduction port. The water led to the part can be efficiently vaporized in advance by the vaporization promoting means. In water, water molecules exist as clusters due to hydrogen bonding, so that the efficiency of vaporization can be improved by subdividing the clusters as much as possible and increasing the surface area of the water. Furthermore, since the heat transfer plate that absorbs the heat in the reaction vessel is coupled to the vaporization promotion means, heat is efficiently transferred from the entire reaction vessel to the vaporization promotion means, and the temperature of the vaporization promotion means decreases due to the latent heat of vaporization. Can be prevented, and the excellent vaporization efficiency of the vaporization promoting means can be maintained. In this way, since the introduced water is efficiently vaporized in advance by the vaporization promoting means, it is possible to prevent water from being directly introduced into the metal storage portion and locally reducing the temperature of the metal storage portion due to water vaporization. The hydrogen generation reaction can be performed uniformly and stably.

The vaporization promoting means is a wick knitted with metal fibers. When water is introduced into the wick, the water cluster is easily fragmented by capillary action and diffusion, and can be efficiently vaporized. Further, the vaporization accelerating means is welded to a portion where the surface of the heat transfer plate has been treated to increase the surface area. When water spreads on the surface of the heat transfer plate that has been treated to increase the surface area, the surface area of the water increases and the water clusters are subdivided, so that the water can be efficiently vaporized. As such treatment, it is preferable to provide a fin shape on the surface, provide dimple holes, or perform rough surface treatment by blasting.

  The hydrogen generator according to the present invention may further include a tank for storing water, and the wick may be configured to extend from the heat transfer plate to the tank through the water inlet. The water in the tank is guided to the heat transfer plate in the vaporization space due to wick capillarity, so water is introduced into the vaporization space without supplying water into the reaction vessel by a power device such as a pump. Can be vaporized.

It is preferable that the metal storage portion also stores a metal that generates heat due to a chemical reaction with oxygen, and the heat transfer plate preferably extends from the vaporization promoting means to the inside of the metal storage portion. Thus, an exothermic reaction proceeds due to a chemical reaction (oxidation) between oxygen and metal (for example, the reaction formula when iron is used as a metal is Fe + 3 / 4O ₂ → 1 / 2Fe ₂ O ₃ , ΔH = − 412.1 kJ / mol, 298.15 K, 101.3 kPa), without the need to heat from the outside of the metal storage unit with an electric heater or the like, by simply introducing oxygen into the metal storage unit up to the predetermined temperature Can be heated. In addition, since the heat transfer plate extends inside the metal storage portion, the heat generated in the metal storage portion heats the vaporization promotion means via the heat transfer plate, and an electric heater etc. that heats the vaporization promotion means Can also be made unnecessary.

In addition, since the reaction of generating hydrogen with water and metal is also an exothermic reaction (for example, in the case of iron, Fe + 4 / 3H ₂ O → 1 / 3Fe ₃ O ₄ + 4 / 3H ₂ , ΔH = −50.4 kJ / mol, 298.15 K, 101.3 kPa), and heat is generated in the metal storage portion even while water is introduced to generate hydrogen. A metal that generates heat by a chemical reaction with oxygen and a metal that generates hydrogen by a chemical reaction with water are stored in the same metal storage unit in the reaction vessel, and these metals are fixed in the metal storage unit. Since this is a so-called fixed bed flow reaction, heat generated by the reaction with oxygen and water is stably stored in the metal housing. Therefore, after the oxygen is first introduced and reaches a predetermined temperature, the temperature of the vaporization promoting means can be maintained from the metal storage portion via the heat transfer plate only by introducing water and the metal storage. Hydrogen can be generated efficiently in the section.

Furthermore, oxygen can be introduced during the introduction of water, and the reaction of generating hydrogen with water and metal and the reaction of generating heat with oxygen and metal can be performed simultaneously. Note that the metal oxidized by the reaction with water also reacts with oxygen to be further oxidized and generate heat. For example, iron that has become Fe ₃ O ₄ also proceeds rapidly to Fe ₂ O ₃ at a high temperature of 200 ° C. or higher (Fe ₃ O ₄ + 1 / 4O ₂ → 3/2 Fe ₂ O ₃ , ΔH = − 118 kJ / mol, 298.15 K, 101.3 kPa). Therefore, the temperature in the reaction vessel can be controlled by introducing oxygen together with water as necessary. At this time, air can be introduced instead of pure oxygen. In this case, oxygen in the air is oxidized and consumed, but nitrogen and other gases such as carbon dioxide are discharged together with hydrogen. When there is a possibility that a minute amount of carbon dioxide may be reduced to carbon monoxide by iron, it is preferable that carbon dioxide is absorbed through caustic soda or lime water before air is introduced into the metal storage part. .

In addition, although the metal which produced | generated hydrogen will be oxidized by said reaction, hydrogen can be repeatedly generated again by reduce | restoring this oxidized metal. In addition, the metal that generates heat due to oxygen is also oxidized by the above-mentioned reaction. Similarly, it can be repeatedly generated by oxygen again by reduction. For example, the reaction formula when using iron as the metal and hydrogen as the reducing gas can be expressed as Fe ₂ O ₃ + 3H ₂ → 2Fe + 3H ₂ O or Fe ₃ O ₄ + 4H ₂ → 3Fe + 4H ₂ O.

  The metal that generates hydrogen by a chemical reaction with water is any one of iron (Fe), indium (In), tin (Sn), magnesium (Mg), and cerium (Ce) or an oxide thereof. Is preferred. These metals have higher hydrogen generation efficiency and superior durability against repeated redox than other metals that react with water to produce hydrogen. Moreover, these metals can be used as a metal which generates heat by a chemical reaction with oxygen.

  The iron is preferably pure iron powder of at least one of cast iron powder, reduced iron powder, electrolytic iron powder, and atomized iron powder. By using such pure iron powder, the reactivity with oxygen and water can be improved, the temperature in the reaction vessel can be increased efficiently, and the hydrogen generation rate can also be improved.

  Examples of the metal that generates hydrogen by a chemical reaction with water include iron or iron oxide, titanium (Ti), zirconium (Zr), vanadium (V), niobium (Nb), chromium (Cr), molybdenum ( It is preferable to add a first group of metals consisting of Mo), aluminum (Al), gallium (Ga), magnesium (Mg), scandium (Sc), nickel (Ni), copper (Cu) and neodymium (Nd). . When these first group metals are added, when iron is repeatedly used in the oxidation-reduction reaction, particle growth due to sintering is suppressed, and a decrease in hydrogen generation efficiency is suppressed. Further, it is preferable to add a second group of metals consisting of rhodium (Rh), iridium (Ir), platinum (Pt), ruthenium (Ru) and palladium (Pd). When these second group metals are added, hydrogen can be generated at a low temperature of 200 ° C. or lower without increasing the self-heating temperature of iron. That is, the oxidation amount of iron by oxygen can be reduced, the reaction of iron and water can be increased, and as a result, the amount of hydrogen generation can be increased. In addition, it is possible to add at least two kinds of metals selected from the first group and the second group in combination, or at least one kind selected from each group.

  As described above, according to the present invention, there is provided a hydrogen generator capable of stably generating hydrogen without generating carbon monoxide or carbon dioxide as a by-product and without requiring a large amount of electric energy. Can do.

Embodiments of the present invention will be described below with reference to the accompanying drawings.
(First embodiment)
FIG. 1 is a cross-sectional view schematically showing an embodiment of a hydrogen generator according to the present invention. As shown in FIG. 1, the hydrogen generator according to the present invention includes a reaction vessel 10 for generating hydrogen by chemically reacting water and metal therein, and for supplying water and air into the reaction vessel 10. An introduction pipe 21 and a discharge pipe 22 for discharging hydrogen and unreacted water generated in the reaction vessel 10 and air or nitrogen are provided. The reaction vessel 10 has a rectangular parallelepiped shape, and an introduction port 11 for communicating the inside of the reaction vessel 10 and the inside of the introduction tube 21 and the inside of the reaction vessel 10 and the inside of the discharge tube 21 are communicated on one surface 14 thereof. A discharge port 12 is arranged.

  In the reaction vessel 10, from the surface 14 on which the introduction port 11 and the discharge port 12 are arranged to be two layers of a layer having the introduction port 11 and a layer having the discharge port 12, the surface 15 is opposed to the opposite surface 15. And a heat transfer plate 30 extending linearly. The heat transfer plate 30 is provided with a vent hole 31 at a position closer to the facing surface 15 than an intermediate point between the placement surface 14 such as the introduction port 11 and the facing surface 15 in order to communicate both layers.

  The layer including the introduction port 11 is further divided by a filter 41 into a metal storage portion 17a for storing a metal that generates hydrogen by reacting with water and a vaporization space portion 18 for vaporizing the introduced water. Partition. The vaporization space 18 is located between the inlet 11 and the metal storage part 17a. The filter 41 allows water and air to be introduced to pass therethrough but does not allow the contained metal to pass therethrough. On the other hand, the layer including the introduction port 11 constitutes a metal storage portion 17b that stores a metal that generates hydrogen by reacting with water in a fixed state. A filter 42 is provided between the metal storage portion 17 b and the discharge port 12 in order to prevent metal from scattering from within the reaction vessel 10. The filter 42 allows the generated hydrogen, unreacted water, air, and nitrogen to pass through, but does not allow the contained metal to pass through.

  As the metal stored in the metal storage portion 17, iron (Fe), indium (In), tin (Sn), magnesium (from the viewpoint of high hydrogen generation efficiency and excellent durability against repeated oxidation and reduction, It is preferable to use any one of Mg) and cerium (Ce), and among these, Fe is more preferable. Moreover, these metals are not restricted to a pure metal state, For example, low valence metal oxides, such as FeO, may be sufficient. Pure metal or low-valent metal oxide is a powder of 1 nm to 100 μm, preferably 1 nm to 10 μm, and can be used as a hydrogen generating medium even in a powder form as it is. It is preferable to select a shape suitable for the reaction and store it in the metal storage unit 17. The pure metal or metal oxide can be supported on any one of alumina, zinc oxide, magnesia, silica, and titania (the metal oxide described in International Publication No. 01/096233 pamphlet, It can be used as a metal oxide according to the present invention). Note that the above metal can be used as a metal that generates heat by a chemical reaction with oxygen.

  In the case of using Fe or a low-valent metal oxide of Fe, it is preferable to add a metal other than Fe in order to increase the generation efficiency of hydrogen. As the metal to be added, titanium (Ti), zirconium (Zr), vanadium (V), niobium (Nb), chromium (Cr), molybdenum (Mo), aluminum (Al), gallium (Ga), magnesium (Mg) , Scandium (Sc), nickel (Ni), copper (Cu), neodymium (Nd), at least one metal selected from the first group, or rhodium (Rh), iridium (Ir), platinum (Pt It is preferable to add at least one metal selected from the second group consisting of ruthenium (Ru) and palladium (Pd). Among these, Mo and Al are more preferable as the first group, and Rh and Ir are more preferable as the second group. Further, at least two kinds of metals selected at least one from each of the first group and the second group can be added. As for the compounding ratio of the metal to add, 0.1-30 mol% is preferable and 0.5-15 mol% is more preferable when all the metals are 100 mol%. When the blending ratio is less than 0.1 mol%, the effect of improving the hydrogen generation efficiency is not recognized. On the other hand, if it exceeds 30 mol%, the efficiency of Fe redox reaction is lowered, which is not preferable. The preparation method of Fe and the metal to be added is performed by a physical mixing method, an impregnation method, a coprecipitation method, or the like, and the coprecipitation method is particularly preferable.

  The heat transfer plate 30 is preferably made of a metal having a higher thermal conductivity than the metal stored in the metal storage portion 17, and specifically, copper, brass, aluminum, or the like can be used. Note that iron, stainless steel, or the like can be used depending on the type and shape of the metal stored in the metal storage unit 17. The heat transfer plate 30 extends over both the arrangement surface 14 such as the introduction port 11 and the opposite surface 15 thereof, but heat transfer is performed so that the heat transfer plate 30 does not block the introduction port 11 and the discharge port 12. A hole is provided in the plate 30.

  Further, a wick 50 knitted with fibers is welded to the surface of the heat transfer plate 30 on the arrangement surface 14. As the fibers, metal fibers are preferable, and fibers such as copper (Cu), brass (Cu—Zn), and aluminum (Al) are more preferable because they are particularly heat resistant and have excellent thermal conductivity. In addition, metal fibers such as iron and stainless steel can be used, and ceramic fibers and heat-resistant resin fibers can also be used.

  The reaction vessel 10 is made of a metal such as stainless steel or aluminum, a ceramic such as alumina or zirconia, or a heat-resistant plastic such as phenol resin or polyphenylene sulfide, and has a structure that can withstand heat and internal / external pressure. . Although a rectangular parallelepiped shape is shown in FIG. 1, it may be another hexahedron, a columnar shape or a truncated cone shape. When reaction container 10 becomes high temperature, it is preferable to cover reaction container 10 with a heat insulating material. As the heat insulating material, glass fiber, silica fiber, silica powder molded body and the like can be used.

  According to the above configuration, first, air is introduced into the reaction vessel 10 from the introduction port 11. The introduced air diffuses through the vaporization space 18 to the entire metal storage portion 17a, and further diffuses through the vent hole 31 to the entire adjacent metal storage portion 17b. The metal in the metal storage part 17 is oxidized by oxygen in the air, and the metal itself is self-heated. As a result, the temperature is raised by itself from a normal temperature to a temperature range sufficient for generating hydrogen. This heat is absorbed and transferred by the heat transfer plate 30 and heats the wick 50 in the vaporization space 18. Air in which all or part of oxygen contained by reaction with metal is consumed is discharged from the discharge port 12.

  Next, when the temperature in the reaction vessel 10 reaches a temperature at which hydrogen can be generated (for example, 100 ° C. or higher), water is introduced into the reaction vessel 10 from the introduction pipe 21 this time. When the introduced water permeates the heated wick 50 in the vaporization space 18, a capillary phenomenon occurs and the surface area increases, so that the water is quickly vaporized to become water vapor. The water vapor diffuses from the vaporization space portion 18 to the metal housing portion 17 a and diffuses to the metal housing portion 17 b through the vent hole 31. The metal in the metal storage part 17 is oxidized by water vapor to generate hydrogen. The generated hydrogen and unreacted water vapor are discharged from the discharge port 12. This gas containing hydrogen is introduced into a system that requires hydrogen, such as a fuel cell.

  Thus, since the wick 50 made of fibers has a very large surface area, water permeates into the wick 50, so that the surface area of the water is increased, the water molecule clusters are subdivided, and the vaporization efficiency is remarkably improved. Can be improved. Although the temperature of the wick 50 in the vaporization space 18 significantly decreases due to vaporization, the wick 50 is provided on the heat transfer plate 30 and the heat transfer plate 30 is provided between the two layers of the metal storage portions 17a and 17b. The heat is efficiently transferred from the entire heated metal in the reaction vessel 10 to the wick 50 via the heat transfer plate 30, and a temperature drop due to vaporization of the wick 50 can be prevented. Since the reaction between the metal in the reaction vessel 10 and water vapor is an exothermic reaction, the temperature of the wick 50 is maintained even if water is continuously supplied into the reaction vessel 10. Therefore, efficient vaporization of water can be stably performed in the vaporization space 18.

  Further, since the heat transfer plate 30 is provided between the introduction port 11 and the discharge port 12, and the ventilation hole 31 is opened at a position away from the introduction port 11 and the discharge port 12 of the heat transfer plate 30, It is possible to prevent the introduced water (water vapor) and air from being exhausted from the outlet 12 without sufficiently reacting with the metal in the reaction vessel 10. That is, the heat transfer plate 30 also functions as a rectifying plate for the introduced gas, and therefore, the metal oxidation reaction with oxygen and water vapor in the reaction vessel 10 can be performed efficiently.

  In the above description, only water is introduced after air is introduced and initially heated. However, air can be introduced together with water after the initial heating. As a result, in the reaction vessel 10, heat can be generated by the reaction of oxygen and metal in the air simultaneously with the generation of hydrogen by the reaction of water vapor and metal. When air is introduced together with water, the temperature in the metal housing portion 17 is further increased as compared with the case where only water is introduced, so that temperature control can be achieved by introducing air. Conditions such as the structure of the reaction vessel, the amount of water and air introduced, and the amount of metal to be filled can be set so that all oxygen in the air is consumed by oxidation of the metal and oxygen is not discharged from the discharge port 12. preferable. Moreover, when there is a possibility that carbon dioxide in the air is reduced to carbon monoxide and discharged together with hydrogen, it is preferable to remove carbon dioxide in advance with caustic soda or the like to introduce the introduced air. Even if carbon dioxide is not removed in advance, the concentration of carbon monoxide can be suppressed to 10 ppm or less which does not significantly poison the electrode of the fuel cell by setting the introduction amounts of water and air. Pure oxygen may be introduced instead of air.

  Further, in the above description, air is introduced into the reaction vessel 10 in order to perform initial heating of the metal in the metal storage portion 17, but instead of introducing air, the reaction vessel 10 is heated by heating means such as an electric heater. The metal in the metal storage part 17 can also be heated from the outside. Even in this case, the heat transfer plate 30 can absorb and transfer heat from the entire metal in the metal housing portion 17 to heat the wick 50 in the vaporization space portion 18. As the heating means, a heater by resistance heating, a positive temperature coefficient thermistor (PTC heater), a heater using oxidation heat of chemical reaction, a heater by catalytic combustion, a heater by induction heating, or the like can be used.

(Second Embodiment)
FIG. 2 is a cross-sectional view schematically showing a form of a hydrogen generator to be used as a reference . In addition, about the structure similar to FIG. 1, the same code | symbol is attached | subjected and the description is abbreviate | omitted. As shown in FIG. 2, in this preferred embodiment, the surface 14 opposite to the face 15 of inlet 11 is disposed, to place the outlet port 12. The inside of the reaction vessel 10 is constituted by a vaporization space 18 on the inlet 11 side and a metal storage part 17 on the outlet 12 side through a filter 41.

  In the vaporization space 18, a disk-shaped evaporation plate 32 is installed at a position facing the introduction port 11. The surface of the evaporation plate 32 has a very large surface area due to blast processing. One end of the heat transfer plate 30 is attached to the center of the back surface of the evaporation plate 32. The evaporation plate 32 is preferably made of the same material as the heat transfer plate 30, and may be welded to the heat transfer plate 30 or may be integrally formed. The heat transfer plate 30 passes through the filter 40, continues into the metal housing portion 17, and extends in a meandering shape (wave shape) from the inlet 11 toward the outlet 12. The opposite end of the heat transfer plate 30 is connected to a filter 42 between the discharge port 12 and the metal storage portion 17.

  According to the above configuration, first, air is introduced into the reaction vessel 10 from the introduction port 11. The introduced air diffuses through the vaporization space 18 and throughout the metal housing 17. The metal in the metal storage part 17 is oxidized by oxygen in the air, and the metal itself is self-heated. As a result, the temperature is raised by itself from a normal temperature to a temperature range sufficient for generating hydrogen. This heat is absorbed and transferred by the heat transfer plate 30 and heats the evaporation plate 30 in the vaporization space 18. Air in which all or part of oxygen contained by reaction with metal is consumed is discharged from the discharge port 12.

  Next, when the temperature in the reaction vessel 10 reaches a temperature at which hydrogen can be generated (for example, 100 ° C. or higher), water is introduced into the reaction vessel 10 from the introduction pipe 21 this time. When the introduced water comes into contact with the blasted surface of the heated evaporation plate 32 in the vaporization space 18, the surface area increases, and thus the water is quickly vaporized to become water vapor. This water vapor diffuses from the vaporization space 18 to the metal storage 17. The metal in the metal storage part 17 is oxidized by water vapor to generate hydrogen. The generated hydrogen and unreacted water vapor are discharged from the discharge port 12. This gas containing hydrogen is introduced into a system that requires hydrogen, such as a fuel cell.

  Thus, since the surface of the blasted evaporation plate 32 has a very large surface area, the surface area of the water is increased by contacting the water here, the water molecule clusters are subdivided, and the vaporization efficiency is remarkably improved. Can be improved. Although the temperature of the evaporation plate 32 is remarkably lowered by vaporization, the heat transfer plate 30 is attached to the evaporation plate 32 and the heat transfer plate 30 is provided so as to meander in the metal storage portion 17. The heat is efficiently transferred from the whole heat-generated metal to the evaporation plate 32 via the heat transfer plate 30, and the temperature drop of the evaporation plate 32 due to vaporization can be prevented. Since the reaction between the metal in the reaction vessel 10 and water vapor is an exothermic reaction, the temperature of the evaporation plate 32 is maintained even if water is continuously supplied into the reaction vessel 10. Therefore, efficient vaporization of water can be stably performed in the vaporization space 18.

In the second embodiment, as shown in FIG. 3, the wick 50 is further welded to the surface of the evaporation plate 32 that has been subjected to the blasting process in the reference embodiment of FIG . Thereby, the vaporization efficiency in the vaporization space 18 can be further improved. Also in this embodiment, as in the first embodiment, air (oxygen) may be introduced at the same time when water is introduced, and instead of introducing air and causing the metal to self-heat, electricity You may heat from the exterior by heating means, such as a heater.

(Third embodiment)
FIG. 4 is a sectional view schematically showing still another embodiment of the hydrogen generator according to the present invention. In addition, about the structure similar to FIGS. 1-3, the same code | symbol is attached | subjected and the description is abbreviate | omitted. As shown in FIG. 4, this embodiment is the same as the second embodiment shown in FIG. 3 , in which a tank 60 filled with water is attached to the reaction vessel 10 and the other end of the introduction pipe 21 a is connected to the tank 60. Connected. For this reason, since the introduction pipe 21a and the introduction port 11a are dedicated to water supply, the introduction port 11b and the introduction pipe 21b for supplying air are separately installed on the surface 14 on which the introduction port 11a is arranged.

  Further, a wick 50 knitted with fibers is welded onto the surface of the evaporation plate 32. This wick 50 passes from the welded evaporation plate 32 through the introduction port 11a dedicated to water supply and the introduction pipe 21a to the tank 60. Extend to the inside. And the front-end | tip of the wick 50 is comprised so that it may be immersed in the water in the tank 60. FIG.

  According to the above configuration, first, when air is introduced from the introduction pipe 21 b, the introduced air diffuses through the vaporization space portion 18 and the entire metal storage portion 17. The metal in the metal storage part 17 is oxidized by oxygen in the air and the metal itself is self-heated. This heat is absorbed and transferred by the heat transfer plate 30 to heat the evaporation plate 30 in the vaporization space 18. On the other hand, the water in the tank 60 moves to the evaporation plate 32 in the vaporization space 18 by the capillary phenomenon of the wick 50 and is vaporized by the heat of the evaporation plate 32. When the reaction vessel 10 reaches a temperature at which hydrogen can be generated (for example, 100 ° C. or more), vaporization in the evaporation plate 32 and the wick 50 is activated, and the generated water vapor diffuses from the vaporization space 18 to the metal storage 17. To do. The metal in the metal storage part 17 is oxidized by water vapor to generate hydrogen.

  In this way, by connecting the vaporization space 18 of the reaction vessel 10 and the water tank 60 with the wick 50 knitted with fibers, the vaporization of water in the vaporization space 18 can be promoted by the capillary phenomenon of the wick 50. Water can be supplied into the vaporization space 18 without using a power device such as a pump. Therefore, by controlling the temperature of the evaporation plate 32, the water in the tank 60 can be automatically vaporized in the vaporization space 18 to form water vapor and supplied to the metal storage unit 17 to generate hydrogen.

  In this embodiment as well, as in the first embodiment, air (oxygen) may be introduced simultaneously when water is introduced, and instead of introducing air and causing the metal to self-heat, electricity You may heat from the exterior by heating means, such as a heater.

(Fourth embodiment)
FIG. 5 is a cross-sectional view schematically showing still another embodiment of the hydrogen generator according to the present invention. In addition, about the structure similar to FIGS. 1-4, the same code | symbol is attached | subjected and the description is abbreviate | omitted. As shown in FIG. 5, in this embodiment, the introduction pipe 21 is installed separately from the introduction pipe 21 a that supplies water into the reaction container 10 and the introduction pipe 21 b that supplies air into the reaction container 10. In addition, the discharge pipe 22 is installed separately from the discharge pipe 22 a that discharges the generated hydrogen and unreacted water, and the discharge pipe 22 b that discharges air or nitrogen from the reaction vessel 10. An introduction pipe 21a for supplying water and a discharge pipe 22a for discharging hydrogen or the like are disposed on one surface 14 of the reaction vessel 10, and an introduction pipe 21b for supplying air, A discharge pipe 22b for discharging is disposed.

  The reaction vessel 10 has a wave-like shape extending at the center position so that the reaction vessel 10 has two layers: a layer in contact with the surface 14 on which the water introduction pipe 21 a is disposed and a layer in contact with the opposing surface 15. It is partitioned by a hot plate 30. A wick 50 is welded to the heat transfer plate 30 on the surface on the arrangement surface 14 side of the water introduction pipe 21a.

  The layer in contact with the arrangement surface 14 of the water introduction pipe 21 a is further partitioned by the filter 41 into the metal storage part 17 a and the vaporization space part 18. The vaporization space 18 is formed between the heat transfer plate 30 and the filter 41 provided at the center position. Then, the water introduction pipe 21 a is extended from the arrangement surface 14 to the metal storage portion 17 a, and the introduction port 21 a that communicates the inside of the water introduction pipe 21 a and the inside of the reaction vessel 10 is installed in the filter 41. A discharge port 12b that communicates the inside of the discharge pipe 22a for hydrogen and the inside of the reaction vessel 10 is installed on the arrangement surface 14, and an introduction port 21b that communicates the inside of the air introduction tube 21b and the inside of the reaction vessel 10 The exhaust port 12b that communicates the inside of the exhaust pipe 21b such as air and the inside of the reaction vessel 10 is installed on the facing surface 15 thereof. On the other hand, the layer in contact with the facing surface 15 constitutes a metal storage portion 17b.

  According to the above configuration, first, air is introduced into the reaction vessel 10 from the inlet 11b. The introduced air diffuses throughout the metal storage portion 17b. The metal in the metal housing portion 17b is oxidized by oxygen in the air, and the metal itself is self-heated. This heat is absorbed and transferred by the heat transfer plate 30 to heat the wick 50 in the vaporization space 18 and heat the metal storage portion 17a. The air in which all or part of oxygen contained by reacting with the metal is consumed is discharged from the discharge port 12b.

  Next, when the temperature in the reaction vessel 10 reaches a temperature at which hydrogen can be generated (for example, 100 ° C. or higher), water is introduced into the reaction vessel 10 from the inlet 11a. When the introduced water permeates the heated wick 50 in the vaporization space 18, a capillary phenomenon occurs and the surface area increases, so that the water is quickly vaporized to become water vapor. The water vapor diffuses from the vaporization space 18 to the metal storage portion 17a. The metal in the metal storage portion 17a is oxidized by water vapor to generate hydrogen. The generated hydrogen and unreacted water vapor are discharged from the discharge port 12a.

  In this way, the metal container 17 in the reaction container 10 has two layers, and air is supplied to one metal container 17b to generate heat, thereby functioning as a heating means for heating the reaction container 10 and the wick 50. At the same time, water can be supplied to the other metal storage portion 17a to generate hydrogen. Therefore, even if oxygen is supplied at the same time when water is supplied, the metal storage portions 17a and 17b are configured separately. Temperature can be controlled.

(Measurement of vaporization efficiency)
In order to verify the effect of the wick, after heating the evaporation plate with the copper wick welded to the surface and the evaporation plate not welded with the wick to about 130 ° C., each room temperature water was set to 0 ° C. on the evaporation plate. .1 ml was dropped and the time until water was completely evaporated was measured. The results are shown in Table 1. As shown in Table 1, it was confirmed that the evaporation time was shortened to about 1/3 when the wick was present, and the vaporization efficiency was significantly improved by the wick.

(Measurement of hydrogen generation efficiency)
An experiment for actually generating hydrogen was performed using the hydrogen generator shown in FIG. The iron stored in the reaction vessel was prepared by an impregnation method and 3.6 mol% Al was added (BET specific surface area 52.1 m ² / g, average particle diameter 0.11 μm). The sample was formed into a pellet, 11.9 g was placed in a reduction furnace, hydrogen was introduced, and a reduction reaction was performed at 500 ° C. for 2 hours. After reduction, the sample was taken out and weighed in nitrogen as an inert gas, and it was 8.5 g. The wick was made of copper, and the heat transfer plate was made of aluminum. The reaction vessel was made of aluminum, and its outer surface was covered with a heat insulating material made of silica fiber and kept warm.

  The above sample is packed in a metal container in the reaction vessel. First, air from which carbon dioxide has been removed with caustic soda is introduced into the reaction vessel at room temperature at a flow rate of 150 mL / min. The oxidation reaction with oxygen was carried out. Then, 6 minutes after the introduction of air, normal temperature water was introduced into the reaction vessel together with air at a flow rate of 0.1 mL / min. The experiment was completed 60 minutes after the introduction of air. During this time, the hydrogen generation rate and the temperature of the outer surface of the reaction vessel were measured. The result is shown in FIG.

  As shown in FIG. 7, hydrogen was generated immediately at the moment when water was added, and the hydrogen generation rate of about 90 mL / min was stably maintained for about 15 minutes. Thereafter, the hydrogen generation rate decreased with the passage of time, and no hydrogen was generated after 60 minutes. During this time, the total amount of hydrogen generated was 2.5L. During the reaction, nitrogen in the air was contained at about 120 mL / min in addition to hydrogen, but oxygen, carbon dioxide, and carbon monoxide were not detected by a gas chromatograph.

  As a comparative example, an experiment was performed under the same conditions as above except that no hydrogen wick was provided and the hydrogen generator shown in FIG. 6 was used in which the heat transfer plate was an aluminum rectifying plate. The result is shown in FIG. As shown in FIG. 8, the hydrogen generation rate was as low as about 60 mL / min at the maximum, and the total hydrogen generation amount was as very low as 0.8 L. This is presumed that iron in the metal storage portion did not react uniformly because water was not efficiently vaporized in the vaporization space.

It is sectional drawing which shows 1st Embodiment of the hydrogen generator which concerns on this invention simply. It is sectional drawing which shows the form of the hydrogen generator used as a reference simply. The second embodiment of the hydrogen generating apparatus of the present invention is a cross-sectional view schematically illustrating. It is sectional drawing which shows 3rd Embodiment of the hydrogen generator based on this invention simply. It is sectional drawing which shows 4th Embodiment of the hydrogen generator based on this invention simply. It is sectional drawing which shows simply the hydrogen generator used as a comparative example by measurement of hydrogen generation speed. 2 is a graph showing changes in hydrogen generation rate with respect to reaction time in the hydrogen generator of FIG. 1. 7 is a graph showing a change in hydrogen generation rate with respect to reaction time in the hydrogen generator of FIG. 6.

Explanation of symbols

DESCRIPTION OF SYMBOLS 10 Reaction container 11 Inlet port 12 Outlet port 17 Metal storage part 18 Evaporation space part 21 Introducing pipe 22 Exhaust pipe 30 Heat transfer plate 31 Ventilation hole 32 Evaporating plate 41, 42 Filter 50 Wick 60 Tank

Claims (5)

A reaction container having a metal container for storing a metal that generates hydrogen by a chemical reaction with water, a water inlet for introducing water into the reaction container, and a space between the water inlet and the metal container Disposed in the vaporization space portion that vaporizes the water introduced from the water introduction port and then supplies it to the metal storage portion, and is installed in the vaporization space portion to increase the surface area of the water and vaporize the water. A vaporization promoting means for promoting the gasification, and a heat transfer plate coupled to the vaporization promotion means for absorbing heat in the reaction vessel and transferring the heat to the vaporization promotion means, wherein the vaporization promotion means comprises a metal fiber. a wick woven from, the heat transfer plate is copper, brass, aluminum, Ri Do iron or stainless steel, becomes the metal fibers of copper, brass, aluminum, iron or stainless steel, wherein the wick, the vaporizing In the space The surface of the heat transfer plate is welded to a portion treated to increase the surface area, the metal storage portion also stores a metal that generates heat due to a chemical reaction with oxygen, and the heat transfer plate is A hydrogen generator extending in a wave shape from the vaporization promoting means inside the metal storage portion . The hydrogen generator according to claim 1, further comprising a tank for storing water, wherein the wick extends from the heat transfer plate to the tank through the water inlet. The hydrogen generator according to claim 1 or 2 , wherein the metal that generates hydrogen by a chemical reaction with water is any one of iron, indium, tin, magnesium, and cerium or an oxide thereof. The hydrogen generator according to claim 3 , wherein the iron is at least one pure iron powder of cast iron powder, reduced iron powder, electrolytic iron powder, and atomized iron powder. The metal that generates hydrogen by a chemical reaction with water is iron or an oxide of iron, titanium, zirconium, vanadium, niobium, chromium, molybdenum, aluminum, gallium, magnesium, scandium, nickel, copper, and neodymium. At least one metal selected from the group 1 and the second group of the second group consisting of rhodium, iridium, platinum, ruthenium, and palladium, or at least one from each group. The hydrogen generator according to claim 1 or 2 , wherein a total of at least two selected metals are added.

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