JP2010254512A - Method for producing ultrahigh purity hydrogen gas - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a refining method and a producing apparatus where hydrogen gas containing a large amount of impurities becomes highly pure inexpensively and efficiently. <P>SOLUTION: Ultrapure water 32 is charged into a primary hydrogen gas filtrating tank 10, hydrogen gas introduced into the primary hydrogen gas filtrating tank 10 is refined to highly purified primary hydrogen gas while passing through an ultrapure water layer 11 and then introduced to a secondary high purity hydrogen gas filtrating tank 15 passing through a high purity hydrogen gas connecting pipe. In the secondary high purity hydrogen gas filtrating tank 15, a mixing room 16 of the high purity hydrogen gas and the ultrapure water is located downward, an ultrahigh purity hydrogen gas room 19 is located upward. The secondary high purity hydrogen gas filtrating tank 15 has a parting plate 18 which is made of a mesh plate and the like and where a gas and a liquid pass through freely is placed downward, a parting plate 18' which is made of a mesh plate and the like and where the gas and the liquid pass through freely is placed upward and the purity of hydrogen is enhanced by forming a layer where curled wires are filled between the parting plates. <P>COPYRIGHT: (C)2011,JPO&INPIT

Description

  The present invention relates to a method for producing ultra-high purity hydrogen gas and an apparatus for producing the same. In particular, the present invention provides at least 96 to 97 capacity that can be used for fuel cells and the like from existing hydrogen gas containing impurities by an inexpensive and simple method, a safe and efficient method. The present invention relates to a method for producing ultra-high purity hydrogen gas having a purity of at least% (Vol%) and an apparatus for producing the same.

  Hydrogen is an important industrial gas used in the chemical industry and petroleum refining. Recently, it has attracted attention as a clean energy source with low environmental impact. In particular, it is expected to be used for fuel cells for home use and automobiles. With the development of fuel cells, it is indispensable to improve the quality of hydrogen in an inexpensive and efficient and easy way to answer the growing demand for hydrogen.

To purify the gas, there have been methods such as membrane separation or specific gravity separation. However, since hydrogen is the lightest element and has a small particle size, it has been extremely difficult to achieve high purity by conventional specific gravity separation. Moreover, membrane separation was not always satisfactory in terms of efficiency. For example, a Pd membrane permeation method or the like is used. The Pd membrane permeation method utilizes the phenomenon that only atomic hydrogen diffuses and permeates through the structure of the Pd alloy at a temperature above a certain level. Heat to about 420 ° C. The hydrogen gas is physically adsorbed on the surface of the Pd alloy film, dissociates into hydrogen atoms on the surface, further penetrates into the lattice of the Pd alloy in the form of hydrogen ions, and diffuses and permeates the Pd alloy film due to the concentration difference of the hydrogen gas. And passes through the secondary side as pure hydrogen gas. Impurities other than hydrogen cannot permeate the Pd alloy film and are exhausted together with the bleed gas on the primary side of the Pd alloy film. This Pd membrane permeation method has a high apparatus cost per purified gas flow rate, and there is a problem in obtaining a large amount of hydrogen gas efficiently and inexpensively.

In addition, there are gas adsorption separation methods including pressure swing adsorption (PSA) that uses repeated adsorption and desorption by changing the pressure, but the efficiency is poor and it cannot withstand industrial use. The method for purifying hydrogen gas is disclosed in JP-A-6-31104 [Patent Document 1], JP-A-7-242401 [Patent Document 2], and JP-A-10-203803 [Patent Document 3].
Japanese Patent Laid-Open No. 11-29301 [Patent Document 4] and Japanese Patent Laid-Open No. 2003-170018 [Patent Document 5].

JP-A-6-31104 Japanese Patent Laid-Open No. 7-242401 Japanese Patent Laid-Open No. 10-203803 Japanese Patent Laid-Open No. 11-29301 JP 2003-170018 A

There are various methods for generating hydrogen gas, but all of the generated hydrogen gas is a gas containing impurities, so there are problems in using it as it is in fuel cells, etc. There is a demand, and there is a need to respond to it.
Because hydrogen is the lightest element and has a small ionic radius, complete separation from impurities was virtually impossible on an industrial scale. The main impurities are nitrogen, oxygen, carbon dioxide, organic gas such as methane, ethane, propane, and other organic substances. These impurities seem to be easily separated because they have larger specific gravity and ionic radius than hydrogen, but they have a long mean free path as a hydrogen atom gas. A large amount of hydrogen gas is mixed in and is difficult to separate.
There is a need for the development of a technique for obtaining hydrogen gas having sufficient purity for use in fuel cells and the like in a simple, economical, safe and efficient manner.

The present inventor has intensively studied to solve the above problems. As a result, high purity hydrogen gas can be easily achieved by placing ultrapure water in a tank through which hydrogen gas containing impurities passes and forcibly circulating the ultrapure water in the tank with a pump. Knowing that it can be ultra-pure, and installing a layer filled with stainless curl wire in a tank filled with ultra-pure water, ultra-pure water that is forced to circulate the curl wire packed layer On the other hand, hydrogen gas containing impurities is allowed to pass through the curled wire packed bed so as to counter-contact the flow of the ultrapure water. It was found that hydrogen gas can be highly purified efficiently.
By grasping the characteristics of the impurities in the hydrogen gas in reverse, it is possible to give priority to the removal of the impurities by utilizing the affinity between the impurities and water.

Thus, the present invention provides the following aspects.
[1] Improve the purity of hydrogen in hydrogen gas by introducing hydrogen gas containing impurities into a gas filtration tank, which is an ultrapure water tank having an ultrapure water phase, and passing the ultrapure water phase. A hydrogen gas purification method characterized by that.
[2] A stainless steel punching metal plate is placed on the upper and lower parts of the gas filtration tank, which is an ultrapure water tank, filled with stainless curl wire, and an ultrapure water phase filled with ultrapure water is provided there. The hydrogen gas as described in [1] above, wherein hydrogen gas containing impurities introduced into the gas filtration tank is allowed to pass through the ultrapure water phase to increase the purity of hydrogen in the hydrogen gas. Purification method.
[3] Hydrogen that efficiently performs interaction including contact between gaseous hydrogen gas and liquid ultrapure water, utilizing the fact that impurities contained in the raw hydrogen gas can be removed by ultrapure water. In the gas production apparatus, the hydrogen gas production apparatus is a high-purity hydrogen gas production apparatus for producing a high-purity hydrogen gas having a reduced impurity content from a source hydrogen gas containing impurities, wherein the impurities are removed. Raw hydrogen gas supply line for supplying the raw hydrogen gas contained therein, high purity hydrogen gas line for extracting purified high purity hydrogen gas, ultra pure water supply line for supplying ultra pure water, and used water A water discharge line for discharging water and a hydrogen gas filtration tank containing ultrapure water, and for releasing hydrogen gas, which is a gas, into an ultrapure water layer that is a space filled with ultrapure water Equipped with hydrogen gas outlet nozzle Hydrogen gas production apparatus is characterized in that hydrogen gas is a gas which has passed through the ultrapure water layer and a hydrogen gas filtration tank having a high purity hydrogen gas chamber for storing. [4] The hydrogen gas filtration tank has a three-stage structure. The lower stage is an ultrapure water storage tank (ultra pure water chamber), and the upper stage is a purified hydrogen gas tank (high purity hydrogen gas chamber). And an intermediate tank (intermediate chamber) in which a partition plate that allows free passage of gas and liquid is disposed at the upper and lower positions of the middle stage portion and the intermediate portion is filled with a curled wire. [3] The hydrogen gas production apparatus according to [3]. [5] A high-purity hydrogen gas generator comprising at least a primary hydrogen gas filtration tank, a secondary hydrogen gas filtration tank, and a hydrogen gas tank for storing highly purified ultra-high purity hydrogen gas The hydrogen gas production apparatus according to [3] or [4] above, wherein

According to the present invention, it is an extremely simple method, is economically excellent, and can advantageously convert hydrogen gas containing impurities into high-purity hydrogen gas from the viewpoint of environmental load. In addition, the highly purified high purity hydrogen gas and ultrahigh purity hydrogen gas obtained can be suitably used as hydrogen gas for fuel cells, and can be used for other purposes.
Other objects, features, excellence and aspects of the present invention will be apparent to those skilled in the art from the following description. However, it is understood that the description of the present specification, including the following description and the description of specific examples and the like, show preferred embodiments of the present invention and are presented only for explanation. I want. Various changes and / or modifications (or modifications) within the spirit and scope of the present invention disclosed herein will occur to those skilled in the art based on the following description and knowledge from other parts of the present specification. Will be readily apparent. All patent documents cited herein are cited for illustrative purposes and are to be construed in their entirety as part of this specification.

It is a flowchart which shows the outline of an example of the hydrogen gas refinement | purification apparatus by the ultrapure water used in the high purity hydrogen gas generator according to this invention. It is a flowchart which shows the outline of an example of the high purity hydrogen gas generator according to this invention. The outline of the impure hydrogen gas filtration apparatus by the ultrapure water used in Example 1 is shown. 2 is a chart showing total ion chromatography of a gas sample (sample No. 1) obtained by directly collecting hydrogen gas generated by the reaction of [1] in Example 1. The lower chart of FIG. 4 is an enlarged view of the upper chart. In FIG. 4, peak 1: estimated component 2,2,4-trimethylpentane, peak 2: estimated component 2,5,9-trimethyldecane, peak 3: estimated component 2,5,9-trimethyldecane, peak 4: estimated Component 3,5,5-trimethylhexene-1, peak 5: putative component decanal, and 6: putative component n-hexadecanoic acid. It is a chart which shows the total ion chromatography of the hydrogen gas sample (sample No. 2) collected on the ultrapure water after the ultrapure water purification process of [1] in Example 1. The lower chart in FIG. 5 is an enlarged view of the upper chart. In FIG. 5, 3: estimated component 2,5,9-trimethyldecane, and 5: estimated component decanal. The component search result of peak 1 in FIG. 4 is shown. The upper row shows the mass spectrum of peak 1, and the lower row shows the mass spectrum of 2,2,4-trimethylpentane, which is the search component. The result of the component search of peak 2 in FIG. 4 is shown. The upper part shows the mass spectrum of peak 2, and the lower part shows the mass spectrum of 2,5,9-trimethyldecane, which is the search component. The result of the component search of peak 3 in FIG. 4 is shown. The upper part shows the mass spectrum of peak 3, and the lower part shows the mass spectrum of 2,5,9-trimethyldecane, which is the search component. The result of the component search of peak 4 in FIG. 4 is shown. The upper part shows the mass spectrum of peak 4, and the lower part shows the mass spectrum of 3,5,5-trimethylhexene-1, which is the search component. The result of the component search of peak 5 in FIG. 4 is shown. The upper part shows the mass spectrum of peak 5, and the lower part shows the mass spectrum of decanal, which is the search component. The result of the component search of peak 6 in FIG. 4 is shown. The upper row shows the mass spectrum of peak 6, and the lower row shows the mass spectrum of n-hexadecanoic acid, which is a search component.

The present invention teaches a method in which hydrogen gas generated by various methods always contains a large amount of impurities, but the impurities are removed by a simple method to make the hydrogen gas highly pure. Is.
The water structure was clarified in 1997 by Dr. Satoshi Kawada (Kaoru Kawada, Advances in Colloid and Interface Science, 71-72 (1997), pp.299-316). In ultrapure water, water molecules combine to form primary particles with an average of 2 nm, and primary particles combine to form secondary particles with an average of 20 nm. It is said that it is the substance of water that forms secondary particles and vigorously repeats the separation and concentration of these particles.
In other words, since water is repeatedly separated and concentrated of spherical particles, there are plenty of gaps between the water particles, and anything other than water can be easily taken into the gaps. By utilizing such characteristics of water, it can be seen that impurities in hydrogen gas can be removed very simply by passing hydrogen gas through ultrapure water.
If the impurities in the hydrogen gas cannot be removed with water alone, it is possible to pack a punching metal plate or stainless curl wire filler into the water and let the hydrogen gas pass through it. Hydrogen gas can be easily obtained.

Various methods are known as methods for producing hydrogen, and impurities contained in hydrogen gas vary depending on the respective methods for producing hydrogen. The main impurities include nitrogen, oxygen, carbon dioxide gas, organic gas, and the like, and the organic gas includes methane, ethane, propane, and other organic substances. In the present invention, the impurity contained in the source hydrogen gas is not limited to include all of these components, but includes the case where at least a part of them is included. Worldwide, most of the hydrogen is produced by thermochemical methods, and the rest is obtained by electrochemical methods.
Examples of the thermochemical method include a steam reforming method, a partial oxidation method, and a self-heating reforming method. The steam reforming method is a method for obtaining synthesis gas by reacting natural gas (methane), LPG, naphtha, coal, and other resources (mainly including fossil resources) with steam in the presence of a catalyst under high temperature. The obtained synthesis gas mainly contains carbon dioxide (CO ₂ ) and hydrogen (H ₂ ), and also contains unreacted raw material hydrocarbons, carbon monoxide, nitrogen, oxygen, and other impurities. Examples of the steam reforming process include ICI (Imperial Chemical Industries, Ltd.) method and Topso (Haldor Topsoe method), and the process generally includes a raw material desulfurization step, a reforming step, and a purification step. Product hydrogen obtained through the steam reforming process usually has a purity of about 95 to 97%.

The partial oxidation method uses heat generated by partial oxidation of a raw material such as hydrocarbon, and reacts the remaining raw material hydrocarbon with water vapor to obtain a synthesis gas. Heavy oil and coal are used. Examples of the heavy oil gasification process include a GE (General Electric) method (Texaco method) and a Shell method. In the self-heating reforming method, a part of raw materials such as hydrocarbons are combusted with oxygen or air, and the heat generation causes the reforming reaction of hydrocarbons and water vapor in the presence of a catalyst to produce synthesis gas (mixed carbon monoxide and hydrogen). Gas), and the reforming reaction is endothermic. However, since the amount of heat required for the reaction is supplied by the oxidation of the hydrocarbon itself, it is called autothermal reforming. The equipment to be supplied can be downsized. As a raw material, methanol has been used, and recently, technology development using biomass-derived ethanol has been active.
Electrochemical hydrogen production includes water electrolysis. The water electrolysis method includes an alkaline water electrolysis method, a solid polymer electrolyte water electrolysis method, and the like, and includes those using power derived from natural energy such as nuclear power generation and solar power generation.

In the hydrogen gas purification method of the present invention, ultrapure water is used. The ultrapure water is water with extremely high purity, and impurities are removed from the ultrapure water so that the purity is as close as possible to H ₂ O.
The theoretical value of the electrical resistivity (resistivity) of H ₂ O at 25 ° C is 18.25 MΩ · cm (the electrical conductivity (conductivity), which is the inverse thereof, is 0.05479 μS / cm). The closer it is, the lower the electrolyte concentration. The ultrapure water used in the hydrogen gas purification method may be 15 MΩ · cm or more (0.067 μS / cm or less), typically 17 MΩ · cm or more (0.0588 μS / cm or less). Includes water of 18 MΩ · cm or more (0.0555 μS / cm or less). More preferably, water of 0.05 μS / cm or less can be used. Furthermore, the water quality is TOC (Total Organic Carbon, μg / L), the number of fine particles (pieces / L), the number of viable bacteria (pieces / L), dissolved oxygen (μg / L), silica (μg / L to ng / L) ), Cations, anions (μg / L to ng / L), heavy metals (μg / L to ng / L), other elements, ions, molecules (μg / L to ng / L), etc. Is done. Examples of the TOC of the ultrapure water include at least less than 50 μg / L.

In one specific embodiment, the ultrapure water used in the hydrogen gas purification method has a specific resistance of 18M.
Ω · cm or more, TOC 5 ppb or less, ionic silica 1 ppb or less, metals 5 ppb or less in purity, preferably 18 MΩ · cm or more, TOC 1 ppb or less, ionic silica 0.1 ppb or less, metals 5 ppb or less Examples of purity may be mentioned. Here, the metal of 5 ppb or less means that the concentration of each metal such as Na, Ca, Fe and Cu is 5 ppb or less. For electrical resistivity (specific resistance) and electrical conductivity (conductivity), refer to JIS K0552, TOC for JIS K0551, fine particle count for JIS K0554, viable count for JIS K0550, silica for JIS K0555, cation, anion Refer to JIS K0553 and JIS K0556 for ions, and JIS K0553 for heavy metals.

The production of ultrapure water usually uses tap water, well water (groundwater), washing wastewater, etc. as raw water, and after removing fine particles etc. by a pretreatment system, primary pure water treatment system (primary pure water production equipment) and secondary It is carried out by removing dissolved components to the limit with an ultrapure water production apparatus comprising a pure water treatment system (secondary pure water production apparatus).
The pretreatment system is composed of a coagulation sedimentation device, a sand filtration device, an activated carbon filtration device, and the like, and the raw water is turbidized in the process of passing through the device of the present pretreatment system to become pretreatment water.
The obtained pretreated water is generally a two-bed / three-column ion exchange device, a reverse osmosis membrane device, a mixed bed ion exchange device, a vacuum deaeration device, a precision filter, an organic matter decomposition device (ultraviolet irradiation device). In the primary pure water treatment system composed of activated carbon towers, etc., ionic impurities and particulate impurities are removed to make primary pure water, and then organic matter decomposition equipment (ultraviolet irradiation equipment), mixed bed polisher, limited In a secondary pure water treatment system composed of an outer filtration membrane device, a reverse osmosis membrane device, etc., further, impurities such as fine particles remaining, colloidal substances, organic substances, metals and ions are removed to obtain secondary pure water, That is, it becomes ultrapure water. In the mixed bed type polisher, a cartridge in which a strongly acidic cation exchange resin and a strongly basic anion exchange resin are mixed is usually used, and a very small amount of metal ions, carbonate ions, hydrogen carbonate ions, silica ions and the like are used. The effluent from other ion exchange resins is captured.

In one specific aspect, the ultrapure water used in the hydrogen gas purification method means one produced by passing through the secondary pure water treatment system (secondary pure water production apparatus). Good.
Ultrapure water production equipment and plants can be obtained from manufacturers and distributors known in the art. For example, Hitachi Plant Technology, Nomura Micro Science Co., Ltd., Top Water Systems Co., Ltd., TSP Co., Ltd., Kawasaki Koki Co., Ltd., Asahi Glass Co., Ltd. Co., Ltd., Organo Co., Ltd., Nippon Millipore Co., Ltd., US Barnstead, Komatsu Electronics Co., Ltd., and the like, but are not limited thereto. The ultrapure water used in the present hydrogen gas purification method may mean that produced by passing through such an ultrapure water production apparatus or ultrapure water production plant.

In the present invention, hydrogen gas containing impurities (that is, impure hydrogen gas) is brought into contact with ultrapure water to remove the impurities in the hydrogen gas, thereby achieving a hydrogen gas purification process. The In general, impure hydrogen gas is hydrogen gas that inevitably contains impurities. The impure hydrogen gas that is the subject of the present invention may be an existing hydrogen gas containing impurities. Typical examples include hydrogen gas containing at least 5 to 3% by volume (Vol%) of impurities, hydrogen gas containing at least 3 to 1% by volume (Vol%) of impurities, and the like. In a typical embodiment, the contact between the ultrapure water and the impure hydrogen gas is performed by an ultrapure water tank holding ultrapure water, that is, an ultrapure water gas filtration tank (ultrapure water having an ultrapure water phase). Impurity hydrogen gas is introduced into a gas filtration tank (water tank), and hydrogen gas is allowed to pass through ultrapure water.
FIG. 1 is a flowchart showing an outline of an example of a hydrogen gas purification apparatus using ultrapure water used in the high purity hydrogen gas generator according to the present invention.

In FIG. 1, the hydrogen gas filtration tank 55 is an ultrapure water tank.
Is supplied to the piping in the system, and is put into the tank by the washing water circulation pump 70 from the water discharge port 61 arranged at the upper part in the hydrogen gas filtration tank. The ultrapure water is filled in the tank and is held so that the water level is slightly above the water level sensor 51 while being monitored by the water level sensor 51. The ultrapure water put into the tank from the water discharge port 61 flows down in the tank and comes out of the hydrogen gas filtration tank 55 through the water suction port 56. In a normal mode, the ultrapure water is made to flow continuously from the top to the bottom in the tank. In this hydrogen gas purification device, there is a control panel 72, which is linked to the water level sensor 51, the washing water circulation pump 70, the supply water valve, the blow valve, the water quality sensor 74, etc., and receives signals as necessary. Or send control signals to control each.

The impure hydrogen gas is usually pressurized and then injected from the gas inlet 53 into the hydrogen gas-ultra pure water mixing chamber 56 in the tank filled with ultra pure water from the nozzle 54. The hydrogen gas introduced into the hydrogen gas filtration tank 55 becomes small bubbles and rises in the ultrapure water in the tank and reaches the highly purified hydrogen gas chamber 59 where purified hydrogen gas accumulates. . The highly purified hydrogen gas accumulated in the hydrogen gas chamber 59 is taken out from the hydrogen gas outlet 63.
The temperature when hydrogen gas is treated with ultrapure water is not particularly limited, and an optimum temperature can be selected as appropriate. However, it can usually be performed at room temperature. The pressure of hydrogen gas when introduced into the hydrogen gas filtration tank is typically preferably not less than atmospheric pressure, and is not particularly limited, and an optimal pressure can be selected as appropriate, for example, 0.15 MPa Can be selected from the range of ~ 100Mpa, in some cases can be selected from the range of 0.15MPa ~ 70Mpa, and further can be selected from the range of 0.2MPa ~ 35Mpa, preferably in the range of 0.2MPa ~ 20Mpa, more preferably 0.5MPa It can be selected from the range of ~ 10Mpa, and more preferably from the range of 1.0MPa ~ 3.0Mpa. For example, 1.5 Mpa can be employed.

According to the present invention, in the simplest embodiment, impure hydrogen gas is blown into the ultrapure water layer in the tank in which ultrapure water is stored, as in the primary hydrogen gas filtration tank 10 described below with reference to FIG. By adding it, it is possible to carry out a purification treatment. In this method, for example, 88 vol% purity hydrogen gas can be purified to a 95.5 to 96 vol% purity hydrogen gas by a simple and simple method, or can be purified to a higher purity hydrogen gas. .

In another embodiment, as shown in FIG. 1, mesh plates or punching metal plates 58 ′ and 58 are arranged at an upper position and a lower position in the hydrogen gas filtration tank 55, and a curled wire material 57 is filled therebetween. Thus, the turbulent flow is generated in the ultrapure water flow so that the contact with the hydrogen gas bubble is increased so that impurities can be further removed.
Thus, in the present invention, the purity of the hydrogen gas is increased to at least 95 to 96 vol% by allowing the hydrogen gas containing impurities to pass through the ultrapure water gas filtration tank and removing the impurities from the hydrogen gas with ultrapure water. A hydrogen gas purification method is provided.

As is clear from the above, the present invention provides a high-purity hydrogen gas or ultra-high-purity hydrogen gas production apparatus that is a very simple method, is economically superior, and is also advantageous in terms of environmental burden. Can be provided.
The hydrogen gas production equipment uses the fact that impurities contained in the raw hydrogen gas can be removed by ultra pure water, and efficiently performs interaction including contact between gaseous hydrogen gas and liquid ultra pure water. A high-purity hydrogen gas production apparatus that produces high-purity hydrogen gas with reduced impurity content from raw hydrogen gas that contains impurities, or to some extent purified impurity content Is a high-purity hydrogen gas production apparatus that produces ultra-high purity hydrogen gas with a very low impurity content from high-purity hydrogen gas that has been reduced, and supplies raw hydrogen gas that contains impurities Gas supply line (or raw material high-purity hydrogen gas supply line for supplying high-purity hydrogen gas containing impurities) and high-purity hydrogen gas for extracting purified high-purity hydrogen gas IN (or ultra-high purity hydrogen gas line that extracts purified ultra-high purity hydrogen gas), ultra-pure water supply line that supplies ultra-pure water, water discharge line that discharges used water, and ultra-pure water And a hydrogen gas filtration tank containing ultrapure water, or an ultrapure water layer (or an ultrapure water chamber filled with ultrapure water (ultra pure water tank)) filled with ultrapure water. A high-purity hydrogen gas chamber (high-purity hydrogen gas tank) that contains hydrogen gas outlet nozzles for discharging certain hydrogen gas and stores hydrogen gas that has passed through the ultra-pure water layer [or ultra-high-purity hydrogen gas chamber] (Ultra high purity hydrogen gas tank)], including contact between hydrogen gas as a gas and ultra pure water as a liquid in the hydrogen gas filtration tank Characterized by being able to interact To.

In the hydrogen gas filtration tank, the ultrapure water layer through which the hydrogen gas passes is substantially spaced so that impurities contained in the introduced hydrogen gas are removed by the ultrapure water. It can be made more efficient by reducing the size of hydrogen gas gas bubbles in ultra pure water, generating turbulence in the flow of ultra pure water, and / or ultra pure water layer It may be achieved by increasing the thickness of the water (assuming a deep water depth). Normally, during the refining operation, ultrapure water is constantly supplied into the hydrogen gas filtration tank and used water is constantly discharged so that a water flow exists in the ultrapure water layer in the hydrogen gas filtration tank. ing. In general, hydrogen gas that is a gas and ultrapure water that is a liquid are in countercurrent contact with each other in an ultrapure water layer in a hydrogen gas filtration tank.
The hydrogen gas filtration tank includes a water level sensor so that the water level in the ultrapure water filtration tank can be monitored and / or controlled. The movement speed of water is not particularly limited, and an optimal water flow speed can be selected as appropriate, but it can usually be selected from the range of 1.0 cm / sec to 10 m / sec.
It can be selected from a range of ˜5 m / sec, and in a typical example, can be selected from a range of 1.0 m / sec to 3.0 m / sec.

  In one embodiment, the hydrogen gas filtration tank has a three-stage structure, and a ultrapure water storage tank (ultra pure water chamber) is in the lower stage and a purified hydrogen gas tank (high purity hydrogen gas chamber) is in the upper stage. ), And an intermediate tank (intermediate chamber) in which a partition plate that allows free passage of gas and liquid is disposed at the upper and lower positions of the middle step portion and the intermediate portion is filled with a curled wire rod. Here, when the flow of ultrapure water flows in the lower direction, it is disturbed by the curled wire and acts to remove the rising bubbles of hydrogen gas and the impurities in the hydrogen gas more efficiently. This hydrogen gas production apparatus is provided with a water quality concentration sensor, and can monitor and / or control the water quality in the filtration tank of ultrapure water. The present hydrogen gas production apparatus is linked to a control system so that automatic operation can be performed and / or operation status can be monitored and / or controlled.

According to the present invention, a more efficient and more practical high-purity hydrogen gas generator can be constructed. FIG. 2 is a flowchart showing an outline of an example of the high-purity hydrogen gas generator according to the present invention.
In FIG. 2, 1 is a hydrogen generation tank, 10 is a primary hydrogen gas filtration tank, 15 is a secondary high-purity hydrogen gas filtration tank, and 24 is a high-purity hydrogen gas tank.
In the hydrogen generation tank 1, an aqueous solution of a sodium compound injected from the sodium compound replenishing tank 6 using a sodium compound pressure pump 7 is subjected to a hydrogen generation reaction in the presence of a nickel catalyst unit 2 such as a nickel oxide catalyst. In FIG. 2, 31 is a water level sensor, which detects the amount of liquid sodium compound in the sodium compound replenishing tank 6, and detects the amount of reactive aqueous liquid containing sodium compound in the hydrogen generation tank 1. The hydrogen generation tank 1 is equipped with a water quality sensor 5 connected to the seawater / fresh water inlet 3 and the water quality valve 4 to supply water into the tank 1 and to monitor for water quality management. ing. The hydrogen gas generated in the hydrogen generation tank 1 is introduced into the primary hydrogen gas filtration tank 10 through the hydrogen gas connection pipe 9 through the generation gas pressurizing device 8. The amount of hydrogen gas can be freely changed depending on the capacity of the reaction tank 1, the amount of reactants, their purity, and the like.

As the sodium compound, sodium borohydride capable of generating hydrogen by a hydrolysis reaction can be suitably used. The compound used as the hydrogen generation source can be selected from hydrides such as inorganic hydrides. The hydride may be one selected from metal hydride complex compounds disclosed in JP-A-2001-19401 and JP-A-2002-241102.
Sodium borohydride is stable in alkaline aqueous solution and in dry air, and the presence of metal salts such as iron, cobalt, nickel, platinum, rhodium, ruthenium, etc. promotes hydrogen generation reaction in water. The Catalysts that catalyze the generation of hydrogen by hydrolysis of sodium borohydride include Ni catalysts such as Raney nickel catalysts, Co catalysts such as Raney cobalt catalysts, alloy catalysts such as sponge Ni-Co alloy catalysts, nickel oxide catalysts Etc. may be appropriately selected from those known in the art.

Ultrapure water 32 is placed in the primary hydrogen gas filtration tank 10, and the hydrogen gas introduced into the primary hydrogen gas filtration tank 10 is purified while passing through the ultrapure water layer 11 to become highly purified primary hydrogen gas. Then, it is introduced into the secondary high-purity hydrogen gas filtration tank 15 through the high-purity hydrogen gas connection pipe. In the primary hydrogen gas filtration tank 10, ultrapure water 32 is placed at about one third of the height of the tank.
The primary hydrogen gas filtration tank 10 is provided with a sensor 13 connected to the ultrapure water inlet 33 and the valve 12 to supply ultrapure water into the filtration tank 10 and to monitor for water quality management. It is possible. Moreover, the filtration tank 10 has a water level sensor 31 and can monitor the amount of water in the tank.
The secondary high-purity hydrogen gas filtration tank 15 is provided with an ultrapure water replenishment pipe 21 so that ultrapure water can be supplied and discharged via the pump 20, and the ultrapure water in the tank 15 is supplied. A water level sensor 31 is also provided so that the water level can be monitored. In the secondary high purity hydrogen gas filtration tank 15, a high purity hydrogen gas / ultra pure water mixing chamber 16 is positioned below, and an ultra high purity hydrogen gas chamber 19 is positioned above.

In one preferred specific embodiment of the present invention, the secondary high-purity hydrogen gas filtration tank 15 has a three-stage structure, and the first stage of the lower stage has an ultrapure water storage tank, in which the primary hydrogen gas filtration tank is provided. Hydrogen gas that has passed through the tank 10 is sent. For example, the purity of hydrogen gas is 96 to 97 vol% at this stage. In this secondary hydrogen gas filtration tank, ultrapure water flows from the upper tank to the lower tank by a circulation pump, and hydrogen gas flows from the lower tank to the upper tank and is convected. In the secondary high-purity hydrogen gas filtration tank 15, a partition plate 18 through which a gas or a liquid such as a mesh plate (or punching metal plate) can freely pass is provided below, and a mesh plate (or punching metal plate) is also provided above the partition plate 18. A partition plate 18 'through which a gas or liquid such as) can freely pass is provided, and a layer filled with a curled wire can be formed between them. The contact efficiency of hydrogen gas and ultrapure water is increased by the action of the stainless steel curled wire 17 sandwiched between the punching metal partition plates in the upper and lower tanks. Impurities are adsorbed in the gaps between the spherical particles of water, and the hydrogen gas is 99.9vol. % Ultra-high purity and sent to ultra-high purity hydrogen gas tank 24. The layer filled with the curled wire increases the interaction between the flow of ultrapure water flowing from the upper side to the lower side and the gas flow such as hydrogen gas moving from the lower side to the upper side, or impurities in the hydrogen gas are increased. As long as it can be devised so that it can be further reduced and can achieve the same effect, it is not limited to the above, and is selected from the techniques and methods known in the field. May be applied. As the mesh plate, the punching metal plate, and the curled wire, those made of a corrosion-resistant material such as stainless steel (stainless steel) can be preferably used. The level of ultrapure water in the secondary high-purity hydrogen gas filtration tank 15 is controlled to be positioned slightly above the mesh plate 18 ′ during normal operation. The secondary high-purity hydrogen gas filtration tank 15 is also provided with a sensor 13 connected to the valve 22 so that it is possible to monitor the water quality in the filtration tank 15.

In general, in the purification method of this hydrogen gas with ultrapure water, the ultrapure water stream and the hydrogen gas stream containing impurities are allowed to interact countercurrently, so that the hydrogen gas is highly purified. It is done. The interaction between the ultrapure water stream and the hydrogen gas stream containing impurities can also be adjusted by controlling the size and / or number of bubbles in the hydrogen gas stream moving as bubbles in the water. In general, when the bubble size is reduced or the number of bubbles is increased, impurities in the hydrogen gas can be further reduced.
The ultra-high purity hydrogen gas obtained by purification through the ultra-pure water layer is then supplied to the hydrogen gas connecting pipe 23.
It is sent to the hydrogen gas tank 24 through. The hydrogen gas tank 24 may be provided with a drain valve 28, and a detection device 29 and a pump connected thereto.
The ultrahigh purity hydrogen gas thus obtained is supplied to the hydrogen fuel cell 25 and the hydrogen fuel combustion furnace 26 via the ultrahigh purity hydrogen gas connection pipe 27.

According to one specific embodiment described above, for example, by passing an impure hydrogen gas having a hydrogen purity of 85 to 89 vol% as the hydrogen gas containing impurities as a starting gas through the primary hydrogen gas filtration tank 10, A high-purity hydrogen gas having a purity of hydrogen gas of 95 vol% or higher, for example, 95 to 98 vol% or higher is obtained, and thus obtained 95 vol% or higher, for example, at least 95 to 98 vol% By passing high purity hydrogen gas whose purity of hydrogen gas is raised to one or more through the secondary high purity hydrogen gas filtration tank 15, the purity of hydrogen gas is either 97 to 99.999999 vol% or more. The high purity hydrogen gas raised above is obtained. In one preferred embodiment, the high purity hydrogen gas having a purity of hydrogen gas of at least 96 to 97 vol% or more is passed through the secondary high purity hydrogen gas filtration tank 15 to pass hydrogen gas. A high-purity hydrogen gas having a purity of 97-99.9 vol% or higher is obtained.

In one specific example, the primary hydrogen gas filtration tank 10 is filled with ultrapure water 32 so as to be about one-third of the tank of the tank. The gas having a purity of 89 vol% is passed through. The high purity hydrogen gas that has passed through the primary hydrogen gas filtration tank 10 then passes through the secondary high purity hydrogen gas filtration tank 15. The secondary high-purity hydrogen gas filtration tank 15 has a three-stage structure, and the first stage of the lower stage has a storage tank for ultrapure water, and hydrogen gas that has passed through the primary hydrogen gas filtration tank 10 is sent to it. . At this stage, the purity of hydrogen gas is 96 to 97 vol%.
In this secondary hydrogen gas filtration tank, ultrapure water flows from the upper tank to the lower tank by a circulation pump, and hydrogen gas flows from the lower tank to the upper tank and is convected. The contact efficiency of hydrogen gas and ultrapure water is increased by the action of the stainless steel curled wire 17 sandwiched between the punching metal partition plates in the upper and lower tanks. Impurities are adsorbed in the gaps between the spherical particles of water, and the hydrogen gas is 99.9vol. % Ultra-high purity and sent to ultra-high purity hydrogen gas tank 24.
Thus, according to the present invention, stainless steel punching metal plates are placed on the upper and lower sides of the ultrapure water gas filtration tank, and the stainless curl wire is filled between them to fill the curl wire filling portion in the gas filtration tank. As described above, ultrapure water is put into the gas filtration tank, and a purity of 99.9 vol% or more is obtained by passing high purity hydrogen gas in which the purity of hydrogen gas is increased to at least 95 to 96 vol% or more. Provided is a hydrogen gas purification method characterized by obtaining ultra-high purity hydrogen gas.

As is apparent from the above, the present invention provides an ultra-high purity hydrogen gas generator.
The ultra high purity hydrogen gas generator is an extremely simple method by performing hydrogen gas purification treatment with ultra pure water in at least two stages, is economically superior, and is also advantageous in terms of environmental load. There is something that can be performed from generation of hydrogen to high purity. The ultra-high purity hydrogen gas generator includes a hydrogen generation tank, a primary hydrogen gas filtration tank, a secondary hydrogen gas filtration tank, and a hydrogen gas tank for storing highly purified ultra-high purity hydrogen gas. Furthermore, the hydrogen gas generated in the hydrogen gas generation tank was pressurized by a pressurizing device and then purified by the hydrogen gas connection line for introducing the hydrogen gas generation tank into the primary hydrogen gas filtration tank. Purified by high purity hydrogen gas connection line for introducing high purity hydrogen gas into secondary hydrogen gas filtration tank through nozzle provided in secondary hydrogen gas filtration tank, and secondary hydrogen gas filtration tank An ultra-high purity hydrogen gas connection line for introducing the ultra-high purity hydrogen gas into a hydrogen gas tank for ultra-high purity hydrogen gas storage, the primary hydrogen gas filtration tank and the secondary hydrogen gas filtration tank, Both ultrapure water supply Comprising a down and water discharge lines, it is characterized in that purification by passing ultrapure water layer of the hydrogen gas filtration tank hydrogen gas is made.
The hydrogen gas filtration tank is equipped with a water level sensor to monitor and / or monitor the water level in the ultrapure water filtration tank.
Or it can be controlled.

  In one typical embodiment, the secondary hydrogen gas filtration tank has a three-stage structure. The ultrapure water storage tank (ultra pure water chamber) is in the lower stage, and the purified hydrogen gas tank (ultra pure water chamber) is in the upper stage. High-purity hydrogen gas chamber), with an intermediate tank (intermediate chamber) in which a partition plate that allows free passage of gas and liquid is arranged at the upper and lower positions of the middle stage portion, and the intermediate portion is filled with curled wire Can be. Here, when the flow of ultrapure water flows in the lower direction, it is disturbed by the curled wire and acts to remove the rising bubbles of hydrogen gas and the impurities in the hydrogen gas more efficiently. The ultra high purity hydrogen gas generator is provided with a water quality concentration sensor, and can monitor and / or control the water quality in a filtration tank of ultra pure water. The ultra-high purity hydrogen gas generator is linked to a control system so that automatic operation is possible and / or monitoring and / or control of operating conditions is possible.

The hydrogen gas product obtained by the hydrogen gas purification technology using ultrapure water of the present invention can be used as a clean energy source for a fuel cell, and is a stationary fuel cell, an automobile fuel cell, a household fuel cell, a portable type Applications such as fuel cells, hydrogen fuel engines, hydrogen fuel turbines, petroleum refining (decomposition and desulfurization), ammonia, methanol, silicon for semiconductors, chemical raw materials for the production of optical fibers, etc., in the steel industry, semiconductor industry, electronics industry, etc. Is available.
The obtained hydrogen gas can also be used for purification of hydrogen gas produced by a small-scale distributed hydrogen production apparatus.
The present invention will be described in detail with reference to the following examples, which are provided merely for the purpose of illustrating the present invention and for reference to specific embodiments thereof. These exemplifications are for explaining specific specific embodiments of the present invention, but are not intended to limit or limit the scope of the invention disclosed in the present application. In the present invention, it should be understood that various embodiments based on the idea of the present specification are possible.
All examples were performed or can be performed using standard techniques, except as otherwise described in detail, and are well known and routine to those skilled in the art. .

[1] When a powdered nickel alloy catalyst (3 kg) is placed in water and 1 kg of sodium borohydride (NaBH ₄ ) is added thereto, a chemical reaction proceeds vigorously in water to easily obtain a large amount of hydrogen gas. Can do. About 2,660 liters of gas mixture mainly containing hydrogen is generated in 5 minutes.
The purity of the hydrogen gas obtained by this reaction is 89 vol%.

[2] The hydrogen gas obtained in the above [1] was introduced as “impure hydrogen gas” into a hydrogen gas filtration device for purification. The outline of the hydrogen gas filter is shown in FIG.
In FIG. 3, the impure hydrogen gas is introduced into the gas filtration device 85 from the inlet 83. Impure hydrogen gas can be blown into the ultrapure water from the nozzle 84. The gas filtration device 85 uses a primary filter 94, a secondary filter 93, and an ultrapure water obtained by passing through an ultrapure water membrane filter 92 (at least an electrical resistance of 18 megaohms or less) for cleaning. It can be configured to be continuously introduced via the ultrapure water circulation pump 90. In FIG. 3, the water piping system is provided with a cushion tank 96, an automatic air vent valve 97, and a blow 98, has a piping for makeup water 99, and the water quality can be monitored by a water quality concentration sensor 95. .

The level of ultrapure water in the gas filtration device 85 can be adjusted to a predetermined position while monitoring the flow meter 91 using the lower water level sensor 81 and the upper water level sensor 82. it can. Normally, the water level is positioned between the lower water level sensor 81 and the upper water level sensor 82 during operation. In the gas filtration device 85, mesh plates 88 and 88 'are provided at the lower and upper portions, respectively, and a curl line fills the space between the upper mesh plate 88' and the lower mesh plate 88 so as to fill the space. Is filled. For the mesh plate and the curled wire, stainless steel can be used. For example, a SUS304 mesh plate or a SUS304 curled wire can be suitably used. The hydrogen gas blown from the nozzle 84 passes through the ultrapure water-hydrogen gas mixing chamber 86 and flows and is purified so as to rise in the gas filtration device 85, and the purified hydrogen gas is ultrapure hydrogen. Ultra high purity hydrogen gas is obtained from the gas outlet 93 through the gas chamber 89.

[3] A gas sample No. 1 was obtained by directly collecting the hydrogen gas (hydrogen gas containing impurities, ie, impure hydrogen gas) generated by the reaction of [1]. Further, in the hydrogen gas filtration device shown in FIG. 3, the mesh plates 88, 88 ′ and the curled wire therebetween are not installed, and ultrapure water is stored in the device. The ultra-high purity hydrogen collected in ultrapure water after purification with ultrapure water, except that it is used in the same state as above. The gas was designated as gas sample No.2. Using both samples as specimens, gas chromatograph / thermal conductivity detector (GC-TCD) for inorganic gas, gas chromatograph / mass spectrometer (GC-MS) and gas chromatograph with flame ionization detector for organic gas Analyzed by a graph (GC-FID).
The qualitative analysis results of the organic gas components in the sample gas are shown in FIGS. 4 and 5 show the total ion chromatogram of the sample, and FIGS. 6 to 11 show mass spectra of main detection peaks. Table 1 shows the component search results.

Note 1) The estimated component in the table is the component retrieved by collating with the standard substance built in the device.
Note 2) Peaks 2 and 3 are expected to have similar structures because the same components were searched.
Note 3) The range of m / z 35-500 was observed. Methane was confirmed by another detector.
Tables 2 and 3 show the results of quantitative analysis of the gas components in the sample gas.

＊）T-HC（炭化水素類の総量；メタン換算量）：GC-MS測定による主な検出ピークの質量
スペクトルから脂肪族炭化水素類（分岐構造のある脂肪族炭化水素、アルデヒド類、脂肪酸類などの混合物）と推定される。

*) T-HC (total amount of hydrocarbons; methane equivalent amount): aliphatic hydrocarbons (branched aliphatic hydrocarbons, aldehydes, fatty acids) from the mass spectrum of the main detection peaks by GC-MS measurement Etc.).

From the above, it was confirmed that the purity of hydrogen gas can be purified to about 96 vol% by a simple method using ultrapure water. This ultra-high purity hydrogen gas may be connected to the combustion tower as it is, or has a content that can be sufficiently applied even if it is separately used for a fuel cell.

[1] In the same manner as in Example 1, a powdered nickel alloy catalyst is placed in water, sodium borohydride (NaBH ₄ ) is added thereto, and the chemical reaction proceeds in water, so that a large amount of hydrogen gas is generated. obtain. The obtained mixed gas mainly composed of hydrogen was introduced as “impure hydrogen gas” into a hydrogen gas filtration apparatus and purified. The outline of the hydrogen gas filter is as shown in FIG.
In FIG. 3, the impure hydrogen gas is introduced into the gas filtration device 85 from the inlet 83. Impure hydrogen gas is blown into the ultrapure water from the nozzle 84. The gas filter 85 is cleaned with ultrapure water (at least having an electrical resistance of 18 megaohms or less) obtained by passing through a primary filter 94, a secondary filter 93, and a membrane filter 92 for ultrapure water. It is continuously introduced through an ultrapure water circulation pump 90 for use. In FIG. 3, the water piping system is provided with a cushion tank 96, an automatic air vent valve 97, and a blow 98, has a piping for makeup water 99, and the water quality is monitored by a water quality concentration sensor 95.

The level of ultrapure water in the gas filtration device 85 is adjusted to a predetermined position while monitoring the flow meter 91 using the lower water level sensor 81 and the upper water level sensor 82. Normally, the water level is positioned between the lower water level sensor 81 and the upper water level sensor 82 during operation. In the gas filtration device 85, mesh plates 88 and 88 'are provided at the lower and upper portions, respectively, and a curl line fills the space between the upper mesh plate 88' and the lower mesh plate 88 so as to fill the space. Is filled. For the mesh plate and the curled wire, stainless steel can be used. For example, a SUS304 mesh plate or a SUS304 curled wire can be suitably used. In the purification process of the present embodiment, the flow rate of ultrapure water is set to 2 m / sec or more, and the hydrogen gas blown from the nozzle 84 flows countercurrently to the ultrapure water in the gas filtration device 85. Contact. The hydrogen gas blown from the nozzle 84 passes through the ultrapure water-hydrogen gas mixing chamber 86 and flows and is purified so as to rise in the gas filtration device 85, and the purified hydrogen gas is ultrapure hydrogen. Ultra high purity hydrogen gas is obtained from the gas outlet 93 through the gas chamber 89.
It is clear that the present invention is an epoch-making method for easily obtaining high-purity hydrogen gas at an industrial level by focusing on the structure of water to solve the difficult problem of removing impurities in hydrogen gas.

It is possible to meet the demands of applications that require high purity, such as fuel cells for home use and automobiles, and it is possible to provide high-purity hydrogen gas in a simple, economical and safe manner. It can contribute to the development of industries and technologies that use hydrogen gas as an energy source and industrial raw material. Because hydrogen gas can be easily purified at high cost and in large quantities, it can be made into high-purity hydrogen gas, making it suitable for use in various industries such as the automobile industry, semiconductor industry, electronic equipment industry, chemical industry, and oil refining. Yes.
It will be apparent that the invention may be practiced otherwise than as particularly described in the foregoing description and examples. Many modifications and variations of the present invention are possible in light of the above teachings, and thus are within the scope of the claims appended hereto.

1: Hydrogen generation tank 9: Hydrogen gas connection pipe
10: Primary hydrogen gas filtration tank
11: Ultrapure water layer
14: High purity hydrogen gas connection pipe
15: Secondary high purity hydrogen gas filtration tank
16: High purity hydrogen gas / ultra pure water mixing chamber
17: Curl wire
21: Ultrapure water supply pipe
23: Hydrogen gas connection pipe
24: High purity hydrogen gas tank
32: Ultrapure water
33: Ultrapure water inlet
55: Hydrogen gas filtration tank
84: Nozzle
85: Hydrogen gas filter

Claims (5)

Introducing hydrogen gas containing impurities into a gas filtration tank, which is an ultrapure water tank having an ultrapure water phase, and passing the ultrapure water phase to increase the purity of hydrogen in hydrogen gas Hydrogen gas purification method. A stainless steel punching metal plate is placed in the upper and lower parts of the gas filtration tank, which is an ultrapure water tank, and a stainless curl wire is filled between them, and an ultrapure water phase filled with ultrapure water is provided there. 2. The hydrogen gas refining method according to claim 1, wherein the hydrogen gas containing impurities introduced therein is allowed to pass through the ultrapure water phase to increase the purity of hydrogen in the hydrogen gas. A hydrogen gas production system that efficiently performs interaction including contact between gaseous hydrogen gas and liquid ultrapure water, utilizing the fact that impurities contained in the raw hydrogen gas can be removed by ultrapure water. The hydrogen gas production apparatus is a high-purity hydrogen gas production apparatus for producing a high-purity hydrogen gas having a reduced impurity content from a source hydrogen gas containing impurities, the impurity-containing hydrogen gas production apparatus. The raw hydrogen gas supply line that supplies the raw hydrogen gas, the high purity hydrogen gas line that extracts the purified high purity hydrogen gas, the ultra pure water supply line that supplies ultra pure water, and the used water are discharged. A hydrogen gas outlet for discharging a hydrogen gas, which is a gas, into the ultrapure water layer, which is a hydrogen gas filtration tank containing ultrapure water and a space filled with ultrapure water. With nozzle, ultra-pure Hydrogen gas production apparatus of hydrogen gas is a gas which has passed through the layer, characterized in that it comprises a hydrogen gas filtration tank having a high purity hydrogen gas chamber for storing. The hydrogen gas filtration tank has a three-stage structure, and includes a storage tank for ultrapure water in the lower stage and a purified hydrogen gas tank in the upper stage, and a partition plate that allows gas-liquid passage freely at the upper and lower positions of the middle stage. The hydrogen gas production apparatus according to claim 3, further comprising an intermediate tank in which a curled wire is filled in an intermediate portion thereof. A high-purity hydrogen gas generator comprising at least a primary hydrogen gas filtration tank, a secondary hydrogen gas filtration tank, and a hydrogen gas tank for storing highly purified ultra-high purity hydrogen gas. The hydrogen gas production apparatus according to claim 3 or 4, characterized in that:

Images