JP2003146603A - Method for controlling hydrogen generation - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a method for controlling hydrogen generation with simple operation and with quick response by overcoming drawbacks such as complicated operation or defective response in a conventional method. SOLUTION: In a method for generating gaseous hydrogen by feeding an aqueous alkaline solution of a metal hydride complex compound into a reaction zone with a catalyst layer provided therein and bringing the solution into contact with the catalyst, hydrogen generation is controlled by increasing and deceasing a rate of gaseous hydrogen extraction from the reaction zone and also a feed rate into, or a discharge rate from, the reaction zone of the aqueous alkaline solution or both of them, thus changing pressure in the reaction zone, raising or lowering a water level of the aqueous alkaline solution and thus regulating a part of the catalyst layer in contact with the aqueous alkaline solution.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for producing hydrogen gas by bringing an alkaline aqueous solution of a metal-hydrogen complex compound into contact with a catalyst, in order to quickly adjust or stop the production amount or removal amount of hydrogen gas. The present invention relates to a method for controlling hydrogen generation.

[0002]

2. Description of the Related Art A method for generating hydrogen by contacting an alkaline aqueous solution of a metal-hydrogen complex compound with a catalyst such as a hydrogen storage alloy is already known (Japanese Patent Laid-Open No. 2001-19401). In such a method, the amount of generated hydrogen gas is increased or decreased as desired, or in order to stop the generation of hydrogen gas in an emergency, usually, in a batch system, a method of mechanically removing the catalyst body, or immersing the catalyst body, Further, in the continuous system and the circulation system, a method of increasing or decreasing the supply amount of the alkaline aqueous solution of the metal hydrogen complex compound is performed.

However, in order to repeatedly carry out the operation of taking out and immersing the catalyst body, a complicated work is required each time, and when the valve is opened and closed to increase or decrease the supply amount of the alkaline aqueous solution, the catalyst is required. Due to the resistance of the layer, there was a time lag in the inflow and outflow of the alkaline aqueous solution, and the response was poor, and there was a problem that it was not possible to deal with the stop of hydrogen gas generation particularly in an emergency.

[0004]

Under the circumstances described above, the present invention overcomes the disadvantages of the conventional method, such as complicated work and poor response, and is a hydrogen which can be quickly responded by a simple operation. It is made for the purpose of providing a generation control method.

[0005]

Means for Solving the Problems The present inventor has proposed a method of contacting a catalyst with an alkaline aqueous solution of a metal-hydrogen complex compound to adjust the amount of hydrogen gas generated, or to stop the generation of hydrogen gas in an emergency. As a result of intensive studies, it was found that by utilizing the pressure of hydrogen gas staying in the reaction zone, the amount of hydrogen gas generated can be controlled and stopped efficiently and responsively, and the present invention is based on this finding. Came to make.

That is, according to the present invention, an alkaline aqueous solution of a metal-hydrogen complex compound is supplied to a reaction zone provided with a catalyst layer,
In a method of contacting this with a catalyst to generate hydrogen gas, the amount of hydrogen gas taken out from the reaction zone, the amount of the alkaline aqueous solution supplied to the reaction zone or the amount discharged from the reaction zone, or both are increased or decreased. The present invention provides a method for controlling hydrogen generation, which comprises adjusting the contact portion between the catalyst layer and the alkaline aqueous solution by changing the pressure in the reaction zone and raising or lowering the water level of the alkaline aqueous solution. .

[0007]

DETAILED DESCRIPTION OF THE INVENTION The present invention will be described in detail with reference to the accompanying drawings. FIG. 1 is a front view of an example of a hydrogen generator used in the hydrogen generation control method of the present invention, and FIG. 2 is a partially cutaway side view of the hydrogen generator. The generation part 2 is configured by connecting in series. Then, the alkaline aqueous solution of the metal-hydrogen complex compound is introduced into the aqueous solution storage unit 4 via the aqueous solution supply valve 3, and continuously sent to the hydrogen generation unit 7 via the aqueous solution amount control valve 5 and the pipe 6. A hydrogen generating catalyst block 8 is provided in the hydrogen generating section 7 which constitutes this reaction zone.
And the alkaline aqueous solution of the metal-hydrogen complex compound comes into contact with the hydrogen generating catalyst to generate hydrogen gas.

Next, the generated hydrogen gas is sent to the low temperature combustion section 1 through the hydrogen gas amount control valve 9. The low temperature combustion portion 1 includes an air intake hole 10 and steam / air discharge hole 1
It is composed of a closed container provided with 1, in which a hydrogen gas header 12, a catalyst supporting plate 13, a backfire prevention, a heat insulating plate 14, a hydrogen gas supply plate 15 and a heating plate 16 are housed and introduced into the low temperature combustion part 1. The generated hydrogen gas is mixed with an excess amount of air introduced from the air intake hole 10, contacts the catalyst supporting plate 13, and at the same time, is burned at low temperature with the air heated by the heating plate 16 to generate water. The water thus generated is mixed with unreacted air as water vapor, and as wet air,
The water vapor is discharged to the outside through the air discharge hole 11. On the other hand,
An aqueous solution discharge tank 17 is arranged below the hydrogen generation portion 2 and communicates with the hydrogen generation portion 2 via an aqueous solution discharge valve 18.

In the control of hydrogen generation by the method of the present invention, the hydrogen gas amount control valve 9 is opened and closed to increase or decrease the amount of hydrogen gas taken out from the hydrogen generation unit 7, and the aqueous solution amount control valve 5 to the hydrogen generation unit 7 is controlled. Alternatively, by adjusting the aqueous solution discharge valve 18 from the hydrogen generating unit 7 or both, the hydrogen generating unit 7 can be controlled.
By changing the hydrogen gas pressure generated in the system, that is, in the reaction zone, and increasing or decreasing the contact area of the hydrogen generating catalyst block 8 with the alkaline aqueous solution of the metal-hydrogen complex compound, it can be carried out rapidly.

Even when the generation of hydrogen gas is stopped as quickly as possible in an emergency, the hydrogen gas emergency release valve 19 is opened, the aqueous solution amount control valve 5 is closed, and the aqueous solution discharge valve is opened as described above. By opening 18 and shutting off the contact between the hydrogen generating catalyst block 8 and the alkaline aqueous solution of the metal-hydrogen complex compound by the pressure in the system, it can be carried out rapidly.

In this example, the generated hydrogen is brought into contact with the oxidation catalyst together with an excess of air and burned at a low temperature to generate moist air. However, the method of the present invention is, of course, merely intended to generate hydrogen. Can also be used when

The metal-hydrogen complex compound used as one of the raw materials for generating hydrogen in the method of the present invention is, for example, a compound represented by the general formula M ^I M ^III H _4-n R _n (I) or M ^II (M ^III H _{4- n} R _n) is ₂ (II) (n in the formula can be mentioned compounds represented by 0 or an integer of 1 to 3).

In these formulas, M ^I is an alkali metal such as lithium, sodium, potassium and rubidium, and M ^II is an alkaline earth metal such as magnesium.
Calcium, strontium or zinc, M ^III is boron, aluminum or gallium.

R is, for example, an alkyl group such as ethyl group or butyl group, methoxy group, ethoxy group, n-propoxy group, iso-propoxy group, n-butoxy group, i.
an alkoxyl group or an acetoxy group such as a so-butoxy group, a sec-butoxy group, a tert-butoxy group, a 2-methoxyethoxy group, a 2-ethoxymethoxy group,
An acyloxy group such as a propionyloxy group.

Therefore, examples of the metal-hydrogen complex compound represented by the general formula (I) include sodium borohydride (NaBH ₄ ) and lithium aluminum hydride (LiA).
1H ₄ ), sodium trimethoxyborohydride NaB
H (OCH _3), sodium triacetoxyborohydride NaBH (OCOCH _{3) 3,} lithium triethylborohydride _{Li (C 2 H 5) 3} BH, hydrogenated tri -s- butylborohydride lithium Li (s-C ₄ H ₉ ) ₃ BH, lithium tributylborohydride Li (n-C ₄ H ₉ ) ₃ BH, potassium tri-s-butylborohydride K (s-C ₄ H ₉ )
₃ BH, Lithium trimethoxyaluminum hydride Li
AlH (OCH ₃ ) ₃ , lithium monoethoxy hydride LiAlH ₃ (OC ₂ H ₅ ), tri-tert-
Butoxy lithium aluminum hydride, bis hydride (2
-Methoxyethoxy) aluminum sodium and the like can be mentioned. Further, examples of the metal-hydrogen complex compound represented by the general formula (II) include zinc borohydride Zn
(BH ₄ ) ₂ , calcium borohydride Ca (BH ₄ ) ₂ ,
Zinc tetramethoxyborohydride Zn [B (OCH ₃ ) ₂
H ₂ ] ₂ , hexaethoxy borohydride calcium Ca
[B (OC ₂ H ₅ ) ₃ H] _{2 and the} like can be mentioned. These metal-hydrogen complex compounds are known and are commercially available as reagents for selective hydrogenation.

Generally, these metal-hydrogen complex compounds having n of 1 to 3, that is, a part of hydrogen atoms are alkyl groups,
Since those substituted with an alkoxyl group or an acyloxy group have lower reactivity than those not substituted, they can be used when controlling to reduce the amount of hydrogen generation.

In the method of the present invention, the metal-hydrogen complex compound represented by the general formula (I) or (II) may be used alone or in combination of two or more kinds. When these metal hydrogen complex compounds come into contact with water, the reaction formula M ^I M ^III H _4-n R _n + 2H ₂ O → (4-n) H ₂ + M ^I
M ^III O ₂ + nRH or M ^II (M ^III H _4-n R _n ) ₂ + 4H ₂ O → 2 (4-n) H ₂
+ M ^II M ^III ₂ O ₄ + 2nRH (wherein M ^I , M ^II , M ^III , R and n have the same meanings as described above) to generate hydrogen.

Since the amount of hydrogen generated at this time is the sum of the amount of hydrogen generated by decomposition of the metal-hydrogen complex compound itself and the amount of hydrogen generated by decomposition of water, the hydrogen generation efficiency is Very high, for example 10.9% by weight when using sodium borohydride. Moreover, the hydrogen thus obtained has the advantage that it is of high purity and does not contain impurities.

In the method of the present invention, in order to handle these metal-hydrogen complex compounds in a stable state, it is necessary to use them as a solution dissolved in an alkaline aqueous solution. As this alkali, lithium hydroxide, sodium hydroxide,
Alkali metal hydroxides such as potassium hydroxide and quaternary alkylammonium compounds such as tetramethylammonium hydroxide and tetraethylammonium hydroxide are used.

These alkalis are at least 1% by mass,
It is preferably used as an aqueous solution having a concentration of at least 10% by mass. The upper limit of this concentration is the saturated concentration of alkali, but if the concentration is too high, the metal-hydrogen complex compound becomes difficult to dissolve, so it is preferable to select in the range of 30 mass% or less. For example, 8 to 3 for sodium hydroxide
In the case of 0% by mass and potassium hydroxide, the metal-hydrogen complex compound is well dissolved at a concentration in the range of 10 to 25% by mass, and generation of hydrogen is not recognized.

At this time, the higher the concentration of the metal-hydrogen complex compound, the more the amount of hydrogen generated per volume, which is advantageous. Since the solubility of the metal-hydrogen complex compound in an alkaline medium changes as a function of temperature, and there is a significant difference between high temperature and low temperature, a solution in which the metal-hydrogen complex compound is dissolved up to the saturation solubility is crystallized by a change in ambient temperature. Although a phenomenon occurs, even a solution in which a part of the metal-hydrogen complex compound is precipitated does not cause any particular problem in the method of the present invention. In addition, 10 mass% sodium hydroxide aqueous solution 10
The solubility of NaBH ₄ in 0 g is 61 g, and the solubility of KBH ₄ in 100 g of a 10 mass% potassium hydroxide aqueous solution is 15 g. The metal-hydrogen complex-containing alkaline aqueous solution thus prepared is very stable and does not generate hydrogen even when stored for a long time.

If desired, an alcohol such as methyl alcohol or ethyl alcohol, or a water-miscible solvent such as dimethylformamide, dimethylacetamide, ethylene glycol or diethylene glycol may be added to the aqueous alkali metal complex compound-containing alkali solution. it can.

Next, as a hydrogen generating catalyst used to generate hydrogen gas by contacting with the above-mentioned aqueous metal hydrogen complex compound-containing alkali solution, for example, nickel, cobalt, zirconium, rhodium, platinum, palladium,
Known catalysts for hydrogen generation such as silver and gold are used.

A so-called hydrogen storage alloy can also be used as the hydrogen generating catalyst. As such a hydrogen storage alloy, for example, Mg ₂ Ni alloy, Mg ₂ Ni
Mg ₂ Ni-based alloys and ZrN, such as a eutectic alloy of the Mg
Labes phase type AB ₂ type alloys such as i ₂ type alloys and TiNi ₂ type alloys, AB type alloys such as TiFe type alloys, LaNi ₅
AB ₅ type alloys such as type alloys, B such as TiV ₂ type alloys
These which can be arbitrarily selected from CC type alloys may be used alone or in combination of two or more.

Further, the performance of this hydrogen generating catalyst can be remarkably enhanced by the fluorination treatment. This fluorination treatment is performed, for example, by immersing a metal or alloy in an aqueous solution containing a fluorinating agent to form a metal or alloy having a fluorinated surface.

The above fluorinating agent-containing aqueous solution is usually
An aqueous solution containing fluorine ions and alkali ions is used. For example, hydrogen fluoride is added to an aqueous solution containing alkali fluoride at a concentration of about 0.2 to 20% by mass to adjust the pH to 2.0 to 6. It can be prepared by adjusting to about 0.5. The alkali fluoride used at this time is not particularly limited, and those which are easily soluble in water, such as sodium fluoride, potassium fluoride, and ammonium fluoride, are preferable, and potassium fluoride is particularly preferable. These alkali fluorides may be used alone or in combination of two or more.

The preferred concentration of alkali fluoride in the fluorinating agent-containing aqueous solution is 0.3 to 3 mass% for sodium fluoride, 0.5 to 5 mass% for potassium fluoride, and 0 for ammonium fluoride. It is in the range of 0.5 to 8 mass%. If the concentration of the alkali fluoride is lower than the above range, it takes a long time to form the fluorinated surface, which is not practical, and if it is higher than the above range, it is difficult to form a fluorinated surface having a sufficient thickness. , The stabilization effect becomes insufficient.

When the pH of the fluorinating agent-containing aqueous solution is less than 2.0, the metal fluorination reaction on the surface of the metal or alloy rapidly proceeds, so that a uniform fluorinated surface is difficult to be formed. If it exceeds, the metal fluorination reaction rate becomes slow and a fluorinated surface having a sufficient thickness cannot be formed. The preferable range of this pH is 4.5 to 6.0 from the viewpoint of having a moderate metal fluorination reaction rate and forming a fluorinated surface with a uniform and sufficient thickness. The amount of hydrogen fluoride required to adjust to the above pH range is usually 1 to 1 mol of sodium fluoride for 1 mol of alkali fluoride.
3 mol, 0.2 to 3 mol for potassium fluoride, and 0.2 to 1 mol for ammonium fluoride.

In order to form a fluorinated surface on a metal or an alloy by using the fluorinating agent-containing aqueous solution, the metal or alloy is immersed in the fluorinating agent-containing aqueous solution, and usually 0 to 0 under normal pressure. At a temperature of about 80 ° C., preferably in the range of 30 to 60 ° C., the surface has a sufficient thickness, that is, 0.
It is held until a fluorinated surface of about 1 to 1 μm is formed. The time required for this is about 1 to 60 minutes.

In the method of the present invention, the above-mentioned hydrogen generating catalyst is used after being shaped into particles, rods, plates, perforated plates or nets, but it is easy to handle and has a large contact area. It is preferable to use by molding into a porous block.

In the method of the present invention, the contact area between the hydrogen generating catalyst and the alkali aqueous solution of the metal hydrogen complex compound is changed by raising or lowering the water level of the alkali aqueous solution to control the hydrogen generation amount. To do.

Next, when the hydrogen generated in the method of the present invention is burned at a low temperature to produce a mixture of steam and air, that is, wet air, it is necessary to use an oxidation catalyst. Examples of the catalyst include those commonly used as oxidation catalysts, for example, noble metal catalysts such as platinum and palladium. These are preferably used by being supported in the form of a thin film on the surface of foam metal such as nickel or nickel alloy.

This low temperature combustion is carried out in the presence of a large excess of air with respect to the supplied hydrogen gas, for example, in the presence of air containing 5 moles or more of oxygen that reacts with hydrogen to produce water. It is carried out in the presence of air in a volume ratio of 5 times or more, preferably 10 times or more, generally 7 to 15 times.

The mechanism of such low-temperature combustion is that the hydrogen directly ejected from the nozzle and the oxygen in the ambient air directly contact with each other on the surface of the catalyst carrier, whereby 1 g of hydrogen produces 9 g of steam as a product. To generate combustion heat of 121 kJ.

The low temperature combustion, the oxygen of the hydrogen and air are in direct contact, CO ₂ and CO, such as combustion, including hydrocarbons
Does not occur, and because it burns naturally at low temperatures, it does not generate nitrogen oxides such as flame combustion.

Although the combustion heat of the low temperature combustion can directly heat the air, it is usually more largely consumed for heating the catalyst carrier than for heating the surrounding air due to the difference in heat transfer, and the heat transfer is
Radiative heat transfer from the catalyst carrier is mainly used. In order to efficiently receive the radiant heat transfer from the catalyst carrier, a heating body made of a porous material through which air can pass is provided so as to face the catalyst carrier, and the radiant heat received from the catalyst carrier is provided. When air passes through a heating element heated by heat, it exerts a heat sterilization effect while filtering microorganisms in the air. This low temperature combustion is carried out by mixing hydrogen gas and air for 200 to 40
It is carried out in the range of 0 ° C.

The heating element is aluminum, which can withstand heat,
It may be formed of a porous material such as nickel or ceramics, and may have any shape as long as it has a filtering and sterilizing effect, such as a honeycomb, a mesh, a foam, or a non-woven mixture of material fibers. The surface of the heating body can be coated with titanium oxide, a photocatalyst or the like to further give a bactericidal effect.

Next, FIG. 3 is a block diagram showing an example of a control system suitable for carrying out the method of the present invention. In this figure, the main parts of the hydrogen generator are a low temperature combustion part 1, an aqueous solution storage part 4, a hydrogen generating part 7 and an aqueous solution discharge tank 1.
7 between the hydrogen generation part 7 and the low temperature combustion part 1 by a pipe provided with a hydrogen gas amount control valve 9, and between the aqueous solution storage part 4 and the hydrogen generation part 7 an aqueous solution amount control valve 5 And the hydrogen generation part 7 and the aqueous solution discharge tank 17 are connected by a pipeline provided with an aqueous solution discharge valve 18, respectively. In addition, the hydrogen generation unit 7 is provided with a conduit provided with a hydrogen gas emergency release valve 19.

As an accessory to this apparatus, a pressure gauge and a liquid level gauge having a detection end inside the hydrogen generating section 7,
A flow meter interlocking with the hydrogen gas amount control valve 9, a flow meter interlocking with the aqueous solution discharge valve 18, and a flow meter interlocking with the aqueous solution volume control valve 5 are respectively attached, and the above pressure gauge is a pressure converter and a liquid level gauge. And each flow meter is connected to a flow rate controller, and according to the information given thereto, the opening degree of the hydrogen gas amount control valve 9, the aqueous solution amount control valve 5, the aqueous solution discharge valve 18 and the hydrogen gas emergency release valve 19 is controlled. A command for is sent.

As a member constituting this system, any member may be used as long as it has corrosion resistance to an alkaline aqueous solution and has a certain degree of pressure resistance, such as stainless steel and hard plastic. In addition, each of these parts must be designed to withstand the system internal pressure (for example, 5000 mm water column) and the maximum temperature of the aqueous solution (for example, 100 ° C.) required to discharge the aqueous solution when the system is closed. .

The operation of the above system is performed as follows. That is, based on the hydrogen gas generation capacity of the catalyst in the hydrogen generation container, the system pressure for a certain time with the opening of the hydrogen gas amount control valve is detected, and the aqueous solution supply valve and the aqueous solution discharge are detected according to the pressure change. By adjusting the valve to adjust the liquid level height in the catalyst body,
The amount of hydrogen gas generated and the amount taken out are controlled. At this time, the pressure inside the system may be set directly by using a pressure gauge as a detection end, but indirectly by measuring the liquid level height in the catalyst body as a detection end. Such a control system has different auxiliary parts depending on whether a pump is used for a batch type, a continuous type, a cycle type or an aqueous solution transfer, a liquid head is used, etc., but the basic operation of the control system is common. Is.

Next, the control system of the present invention will be described by taking a continuous system as an example. In the hydrogen generating container, when a certain amount of hydrogen gas is generated, the hydrogen gas supply valve has a certain opening according to the flow rate, and the system of the hydrogen generating container also has a certain pressure. Cascaded to this system pressure, the aqueous solution supply valve and the aqueous solution discharge valve have appropriate openings, the liquid surface of the aqueous solution immerses the catalyst body to a certain height, and the aqueous solution passes through the aqueous solution discharge valve. It is discharged to the aqueous solution discharge tank.

When the hydrogen gas generation amount is increased from a predetermined amount, the hydrogen gas amount control valve is operated so as to be larger, and the pressure in the system of the hydrogen generation container is lowered. As a result, the pressure in the system is cascaded, the aqueous solution amount control valve acts to be opened more, the aqueous solution discharge valve acts to close more, and thereafter, by maintaining an appropriate opening degree, Liquid level,
The catalyst body is immersed above a certain height.

On the contrary, when the hydrogen gas generation amount is decreased, the hydrogen gas supply valve is operated so that the opening is further closed to increase the pressure in the system of the hydrogen generation container. The aqueous solution volume control valve is closed more and the aqueous solution discharge valve is opened more, and after that, by maintaining an appropriate opening, the liquid level keeps the catalyst body at a certain level. Dip below the height.

In the case of an emergency stop, if a certain amount of hydrogen gas is generated or if the amount is increasing,
Since the hydrogen gas supply valve is shut off urgently, the pressure in the system of the hydrogen generation container suddenly rises and is cascaded to this system pressure, the aqueous solution volume control valve is closed, and the aqueous solution discharge valve is fully opened. Holds the opening,
The liquid level drops to the lowest position where it does not touch the catalyst body. Then, when the inside of the hydrogen generation container has a pressure higher than the pressure resistance of the container, the hydrogen gas emergency release valve is further opened. Table 1 shows the relationship between these valve operations and the system pressure and the liquid surface height.

[0046]

[Table 1]

The aqueous solution discharge valve has an opening corresponding to the system internal pressure after the initial operation.

[0048]

EXAMPLES Next, the present invention will be described in more detail by way of examples.

Example In a stainless steel container (350 × 100 × 750 mm), a nickel foam (6 with a porosity of 90% having communicating holes) was prepared.
(5 x 65 x 65 mm) surface is fluorinated and cobalt reduced to provide a coating, with a width of 65 mm and a height of 50 at the bottom.
A hydrogen generating container was constructed by arranging 5 blocks each having a dispersion groove with a stainless steel filter having a size of mm in series.

Next, about 6 liters of an aqueous solution prepared by dissolving sodium borohydride (NaBH ₄ ) at a concentration of about 3% by mass in an aqueous solution of 10% by mass sodium hydroxide was placed in the aqueous solution storage tank, and each block was filled with The liquid temperature was adjusted to 40 ° C. by a liquid temperature adjusting sheathed heater arranged in the lower dispersion groove, and 37 g of hydrogen was generated per hour. This amount of hydrogen can generate steam of about 300 ml / hour (amount capable of humidifying 8 tatami mats in a wooden Japanese-style room and 13 tatami mats in a prefabricated western room based on the Japan Denki Kogyo Standard).

Next, a low temperature combustion apparatus was manufactured as follows. First, the catalyst burner is composed of a catalyst carrier, a flashback prevention and heat insulating material, and a hydrogen gas supply plate, and the catalyst carrier for the combustion reaction is a palladium catalyst, and the carrier is a Celmet (material: nickel) plate. I was there. The flashback prevention and heat insulating material is formed by a laminated body of ceramic wool and a mesh spacer made of stainless steel, and on the back side thereof is a gas in which a large number of hydrogen gas injection nozzles for supplying hydrogen gas to the catalyst are arranged. The supply plates are stacked. A rectangular cylindrical manifold is formed at the lower end of a vertical flat space in which a backing plate is arranged behind the gas supply plate, and a hydrogen gas distribution pipe is connected to the manifold. Then 37 g /
Using an excess air ratio of 5 times or more for the hydrogen supply of h,
The catalyst surface temperature was burned at 290 to 325 ° C. In addition to the above catalyst burner, a ceramic air heater having 98% porosity facing the catalyst carrier,
Ceramic wool and stainless steel wire mesh are placed for heat insulation and filtration. The low temperature combustion device part has a width of 350
mm, depth 100 mm, height 300 mm, made of stainless steel, all of which were held in the frame.

By operating under such conditions, the opening of the hydrogen gas amount control valve was set to 50%, and the pressure in the hydrogen generation container was maintained at about 200 mmH ₂ O. Next, when the opening of the aqueous solution amount control valve was adjusted to 50% and the opening of the aqueous solution discharge valve was adjusted to 50%, the liquid surface reached the height of 80% of the catalyst body, and the aqueous solution was discharged at the bottom of the hydrogen generating container. Was discharged to the aqueous solution discharge tank via.

Next, the opening amount of the hydrogen gas amount adjusting valve is decreased, the pressure in the system is increased to 500 mmH ₂ O, the opening amount of the aqueous solution amount adjusting valve is decreased, and the opening amount of the aqueous solution discharge valve is changed. When the position of the liquid surface was increased to about 50% of the height of the catalyst body, the hydrogen gas generation amount decreased to 50%. The time required to reach the steady state at this time was about 40 seconds.

In addition, when the hydrogen gas generation control valve was completely closed in order to carry out a test for making an emergency stop by increasing the hydrogen gas generation amount, the pressure in the hydrogen generation container suddenly increased, and after about 30 seconds, it was about 0. Then, the aqueous solution amount control valve was completely closed, and the aqueous solution discharge valve was fully opened to reach a steady state. At this time, the aqueous solution was rapidly discharged, and the liquid surface was lowered to a position where it did not contact the catalyst body.

[0055]

According to the method of the present invention, hydrogen gas generated by decomposing an alkaline aqueous solution of a metal-hydrogen complex compound can be controlled or stopped with good responsiveness. It can be suitably used for controlling the apparatus for producing clean moist air.

[Brief description of drawings]

1 is a front view of a hydrogen generator suitable for carrying out the method of the present invention.

FIG. 2 is a side view of the same.

FIG. 3 is a block diagram of a control system for performing the method of the present invention.

[Explanation of symbols]

1 Low temperature combustion part 2 Hydrogen generation part 3 Aqueous solution supply valve 4 Aqueous solution storage 5 Aqueous solution control valve 6 pipelines 7 Hydrogen generation part 8 Hydrogen generation catalyst block 9 Hydrogen gas amount control valve 10 Air intake hole 11 Water vapor and air exhaust holes 12 Hydrogen gas header 13 Catalyst support plate 14 Flashback prevention, heat insulation board 15 Hydrogen gas supply plate 16 heating plate 17 Aqueous solution discharge tank 18 Aqueous solution discharge valve 19 Hydrogen gas emergency release valve

[Procedure amendment]

[Submission date] June 12, 2002 (2002.6.1)
2)

[Procedure Amendment 1]

[Document name to be corrected] Drawing

[Name of item to be corrected] Figure 1

[Correction method] Change

[Correction content]

[Figure 1]

[Procedure Amendment 2]

[Document name to be corrected] Drawing

[Name of item to be corrected] Figure 3

[Correction method] Change

[Correction content]

[Figure 3]

Claims (4)

[Claims] 1. A method of supplying an alkaline aqueous solution of a metal-hydrogen complex compound to a reaction zone provided with a catalyst layer, and bringing this into contact with a catalyst to generate hydrogen gas, in addition to the amount of hydrogen gas taken out from the reaction zone. The amount of the alkaline aqueous solution supplied to the reaction zone and / or the amount discharged from the reaction zone is increased / decreased to change the pressure in the reaction zone to raise or lower the water level of the alkaline aqueous solution to form a catalyst layer. A method for controlling hydrogen generation, which comprises adjusting a contact portion with the alkaline aqueous solution. 2. The hydrogen generation control method according to claim 1, which is carried out by detecting the pressure in the reaction zone. 3. The hydrogen generation control method according to claim 1, which is carried out by detecting a height of a contact portion of the catalyst layer with the alkaline aqueous solution. 4. The hydrogen generation according to claim 1, 2 or 3, wherein the hydrogen gas extraction valve from the reaction zone, the alkaline aqueous solution supply valve to the reaction zone or the alkaline aqueous solution discharge valve from the reaction zone is opened and closed. Control method.