JP2016044702A - Hydrogen gas storage bag and hydrogen vehicle hydrogen gas supply and recovery system with hydrogen gas storage bag - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a light weight hydrogen gas storage bag showing no reduction of hydrogen permeation degree due to aging in its use and having a superior operability and a hydrogen vehicle hydrogen supply and recovery system using the hydrogen gas storage bag.SOLUTION: This invention relates to a hydrogen gas storage bag made of film having at least polyvinyl alcohol resin layer, a degree of oxygen permeation using a Gelbo Flex Tester after five times bending of the film is 0.03 cc/mday atm or less and a degree of permeation of gas derived from air when it is exposed to air of 1 atm in the storage bag is 2 cc/mday atm or less.SELECTED DRAWING: None

Description

  The present invention relates to a hydrogen gas storage bag for storing hydrogen gas, and a hydrogen gas supply / recovery system for a hydrogen vehicle using the same.

  In recent years, so-called fuel cell vehicles (FCV) have attracted attention, and vehicles such as railways using fuel cells and vehicles using hydrogen directly as fuel (hereinafter referred to as “hydrogen vehicles”) are also attracting attention. . It is necessary to supply hydrogen to these hydrogen vehicles. For example, in FCV, infrastructure is currently being developed so that hydrogen gas can be charged at a hydrogen station installed in the city (for example, Patent Documents 1 and 2). reference).

JP 2004-192863 A JP 2006-48981 A

In the hydrogen station for FCV, hydrogen gas stored in a high-pressure tank is filled into individual FCVs through gas supply pipes and filling nozzles. It is necessary to extract the hydrogen gas remaining inside. In particular, when high-pressure filling is performed for the purpose of rapid filling, since the amount of gas is large, the danger is very high if the gas remains in the supply pipe. Therefore, it is necessary to perform the operation for extracting the residual gas safely and efficiently in a short time. Conventionally, such residual hydrogen gas has been released into the atmosphere through a vent provided in the piping path, but it is desirable to recover and reuse it from the viewpoint of energy resources.
Then, as a method for recovering the residual hydrogen gas at the hydrogen station, for example, it is considered to temporarily store the residual hydrogen gas in a recovery container. However, the recovery container is lightweight and has excellent operability. What is expected.

As such a recovery container, for example, a hydrogen gas storage bag made of an EVOH resin (ethylene-vinyl acetate copolymer saponified product) film having excellent gas barrier properties has been studied.
However, this storage bag is excellent in terms of flexibility and weight reduction, but the intermolecular void size in the amorphous part of the EVOH resin is large (about 1.5 times the size of oxygen molecules). There is a problem that sufficient gas barrier properties cannot be exhibited for hydrogen molecules having a molecular size smaller than that of the molecules, resulting in an increase in hydrogen permeability. In addition, EVOH resin film vapor-deposited in aluminum to supplement the free volume vacancy size of the amorphous part of EVOH resin is also commercially available, but since the aluminum vapor-deposited layer is poor in bending fatigue resistance, hydrogen gas comprising this film is used. The storage bag currently has pinholes caused by slight bends and cannot exhibit a sufficient hydrogen gas barrier property.

  The present invention has been made in view of such circumstances, and is a hydrogen gas storage bag that is light in weight, has no decrease in hydrogen permeability due to the course of use, and has excellent operability, and hydrogen for a hydrogen vehicle using the same. Its purpose is to provide a gas supply and recovery system.

The inventors of the present invention have made extensive studies to solve the above problems. In the course of the research, the inventors recalled that the hydrogen gas storage bag is made of a lightweight, synthetic resin film, and that the weight, operability, etc. are reduced without causing gas leakage from the bag. As a result, the storage bag is made of a film having at least a polyvinyl alcohol-based resin layer. The oxygen permeability of the film after bending the film five times is 0.03 cc / m ^2. When the permeability of air-derived gas when exposed to 1 atm of the storage bag is ² cc / m ² · day · atm or less, the intended purpose is We have found that this can be achieved and have reached the present invention.

That is, in order to achieve the above object, the present invention is a hydrogen gas storage bag comprising a film provided with at least a polyvinyl alcohol-based resin layer, and the oxygen permeability in a gelbo flex tester after the film is bent five times. Is 0.03 cc / m ² · day · atm or less, and the permeability of the air-derived gas when exposed to 1 atm of the storage bag is ² cc / m ² · day · atm or less. The hydrogen gas storage bag characterized by the above is defined as a first gist.

  In addition, the present inventors have found a more efficient hydrogen gas supply / recovery system for a hydrogen vehicle using the special hydrogen gas storage bag.

That is, according to the present invention, a supply valve, a gas supply pipe, and a hydrogen gas filling nozzle are connected to a high-pressure hydrogen storage tank in this order, and a gas purge pipe is connected to branch the pipe path of the gas supply pipe. In addition, in the hydrogen gas filling apparatus, in which a discharge valve is provided in the middle of the gas purge pipe,
The hydrogen gas filling nozzle is attached to a hydrogen gas receiving portion of a hydrogen vehicle, and a tip of the gas purge pipe is connected to the hydrogen gas storage bag of the first aspect,
With the supply valve opened, the hydrogen in the high-pressure hydrogen storage tank is filled into the hydrogen tank mounted on the hydrogen vehicle, and when the filling is completed, the supply valve is closed and the discharge valve is opened. A hydrogen gas supply / recovery system for a hydrogen vehicle, characterized in that the residual hydrogen gas is recovered in the storage bag.

As described above, the hydrogen gas storage bag of the present invention is made of a film having at least a polyvinyl alcohol-based resin layer, and has an oxygen permeability of 0.03 cc in a gelbo flex tester after the film is bent five times. / ^m 2 · day · atm or less, and, in the storage bag shows the physical properties permeability of the air from the gas ^{2 cc} / m 2 · day · atm or less, such as when exposed to air 1 atm. For this reason, it is lightweight, has excellent hydrogen gas storage properties, and has excellent operability. Therefore, in the hydrogen gas supply / recovery system for a hydrogen vehicle of the present invention, the storage bag can be advantageously used.

  Further, the hydrogen gas supply / recovery system for a hydrogen vehicle according to the present invention can efficiently recover the residual hydrogen gas in the pipe in the storage bag due to the characteristic configuration. Further, since high-pressure filling with hydrogen gas is possible, gas can be rapidly filled, and gas filling can be performed safely and efficiently in a short time. Then, by replacing the storage bag in which residual hydrogen gas is accumulated as needed, the hydrogen vehicle hydrogen gas supply / recovery system of the present invention can be continuously operated, and the storage bag is lightweight. Therefore, the replacement work is also easy.

It is explanatory drawing which shows the hydrogen gas supply and collection | recovery system for fuel cell vehicles using the storage bag of this invention.

  Next, embodiments of the present invention will be described in detail.

The hydrogen gas storage bag (hereinafter abbreviated as “storage bag”) of the present invention is composed of a film having at least a polyvinyl alcohol (PVA) resin layer, as described above. The oxygen permeability of the gelbo flex tester after bending 5 times is 0.03 cc / m ² · day · atm or less, and the permeability of the air-derived gas when exposed to 1 atm of the storage bag is 2 cc. / M ² · day · atm or less. In addition, the oxygen permeability prescribed | regulated to this invention shows the numerical value at the time of measuring according to the method as described in JISK7126 (isobaric method) on the conditions of 23 degreeC x 50% RH.
The “permeability of air-derived gas when exposed to 1 atm of air (cc / m ² · day · atm)” is determined by introducing a certain amount (100 L) of high-purity helium into the storage bag. After the introduced bag is exposed to atmospheric pressure air (1 atm) at 40 ° C., the air-derived gas concentration in the bag is measured by a gas chromatograph, and enters the bag from the outside of the bag by the product with the gas volume in the bag. This can be calculated based on the total volume of the gas (air-derived gas). That is, the type of gas that penetrates (permeates) from the outside of the bag into the bag is the same as the type of gas (air-derived gas such as nitrogen gas and oxygen gas) that constitutes the air used for measurement, but the composition is Do not consider.

As described above, the gas permeability of the storage bag when exposed to 1 atm of air is ² cc / m ² · day · atm or less, preferably 1 cc / m ² · day · atm or less, particularly preferably Is 0.5 cc / m ² · day · atm or less.

Further, the oxygen permeability in the gelboflex tester after bending the film 5 times is 0.03 cc / m ² · day · atm or less, preferably 0.02 cc / m ² · day · atm or less, Particularly preferably, it is 0.01 cc / m ² · day · atm or less.

The ratio (after bending / before bending) of hydrogen permeability (cc / m ² · day · atm) before and after bending of the film is usually 0.5 or less, preferably 0.4 or less.

  As the film, a film having at least a PVA resin layer is used. That is, the PVA-based resin layer expresses a function as a gas barrier layer. In addition, the said PVA-type resin layer can maintain gas barrier ability, without embrittlement before and behind bending like an aluminum vapor deposition layer. In addition, since the hydrogen gas is dried, the PVA resin layer is dried and hydrated water is removed while using the storage bag of the present invention, so that the gas barrier performance is improved. Become. For this reason, the storage bag of the present invention tends to have lower oxygen permeability and hydrogen permeability before and after use.

The PVA resin that is a material of the PVA resin layer is a thermoplastic resin that can be dissolved in water, and examples of the PVA resin used in the present invention include unmodified PVA and modified PVA. Unmodified PVA is produced by homopolymerizing vinyl acetate and further saponifying it. On the other hand, modified PVA includes copolymer-modified PVA and post-modified PVA, and the amount of modification is within a range not impairing the effects of the present invention, and is usually less than 10 mol%. Examples of the unsaturated monomer copolymerizable with vinyl acetate include olefins such as ethylene, propylene, isobutylene, α-octene, α-dodecene, α-octadecene, 3-buten-1-ol, 4- Hydroxyl group-containing α-olefins such as penten-1-ol and 5-hexen-1-ol and derivatives thereof, such as acrylic acid, methacrylic acid, crotonic acid, maleic acid, maleic anhydride, itaconic acid, undecylene Unsaturated acids such as acids or salts thereof, monoesters or dialkyl esters, nitriles such as acrylonitrile and methacrylonitrile, amides such as diacetone acrylamide, acrylamide and methacrylamide, ethylene sulfonic acid, allyl sulfonic acid, methallyl sulfonic acid Olefin sulfone such as Or salts thereof, alkyl vinyl ethers, dimethylallyl vinyl ketone, N-vinyl pyrrolidone, vinyl chloride, vinyl ethylene carbonate, 2,2-dialkyl-4-vinyl-1,3-dioxolane, glycerol monoallyl ether, 3,4 -Vinyl compounds such as diacetoxy-1-butene, substituted vinyl acetates such as isopropenyl acetate and 1-methoxyvinyl acetate, vinylidene chloride, 1,4-diacetoxy-2-butene, vinylene carbonate, and the like. Further, as the PVA resin, a PVA resin having a 1,2-diol bond in the side chain can also be used, and the PVA resin having a 1,2-diol bond in the side chain is, for example, (a) acetic acid A method of saponifying a copolymer of vinyl and 3,4-diacetoxy-1-butene, (a) a method of saponifying and decarboxylating a copolymer of vinyl acetate and vinyl ethylene carbonate, and (c) vinyl acetate. Of saponifying and deketalizing a copolymer of 2,2-dialkyl-4-vinyl-1,3-dioxolane, and (d) saponifying a copolymer of vinyl acetate and glycerol monoallyl ether. Obtained by a method, etc.
Furthermore, as modified PVA, it can also manufacture by post-modifying PVA. Examples of such post-modification methods include a method of converting PVA into acetoacetate ester, acetalization, urethanization, etherification, grafting, phosphoric esterification, and oxyalkylene.

  The saponification degree of the PVA-based resin is usually 90 mol% or more, and a preferable range is 95 to 100 mol%, and a particularly preferable range is 99 to 100 mol%. The average degree of polymerization of the PVA-based resin is usually 1100 or more, a preferred range is 1100 to 4000, and a particularly preferred range is 1200 to 2600.

  The viscosity of the 4% by weight aqueous solution of the PVA-based resin is usually 2.5 to 270 mPa · s (20 ° C.), preferably 2.5 to 112 mPa · s (20 ° C.), particularly preferably 2.5 to 80 mPa. -It is s (20 degreeC). The viscosity is measured according to JIS K 6726.

The method for forming the PVA resin layer (PVA resin film) is not particularly limited, but the PVA resin aqueous composition is supplied to an extruder and melt-kneaded, and then the T-die method and the inflation method. A method in which the film is formed by extrusion and dried is preferable.
The melt kneading temperature in the extruder in such a method is preferably 50 to 170 ° C, particularly 55 to 160 ° C. If the temperature is too low, the film skin will be defective, and if it is too high, the foaming phenomenon tends to occur. Moreover, about the drying of the film after film forming, it is preferable to carry out at 70-120 degreeC, and also it is preferable to carry out at 80-100 degreeC.

  The PVA-based resin film may be either a biaxially stretched film or a uniaxially stretched film, but by using a biaxially stretched film, it is excellent in terms of tear strength and tensile strength.

For such biaxial stretching, the stretching ratio in the machine flow direction (MD direction) is preferably 2.5 to 5 times, and the stretching ratio in the width direction (TD direction) is preferably 2 to 4.5 times, particularly preferably. The MD has a stretching ratio of 3 to 5 times, and the TD direction has a stretching ratio of 2.5 to 4.5 times. That is, if the draw ratio in the MD direction is too low, it is difficult to improve the physical properties by stretching and the gas barrier property tends to be impaired, and if it is too high, the film tends to tear in the MD direction. Further, if the draw ratio in the TD direction is too low, it is difficult to improve physical properties by stretching, and gas barrier properties tend to be impaired. If it is too high, breakage during stretching tends to occur frequently when the film is produced industrially. There is.
In addition, for such biaxial stretching, when performing sequential biaxial stretching or simultaneous biaxial stretching, the water content of the PVA-based resin film may be adjusted to 5 to 70% by weight, particularly 10 to 60% by weight. preferable. The moisture content can be adjusted by a method of continuously drying the PVA resin film before drying, a method of immersing a PVA resin film having a moisture content of less than 5% by weight in water, or adjusting the humidity. Even if the moisture content is too low or too high, there is a tendency that the stretching ratio in the MD direction and the TD direction cannot be increased in the stretching process. In such a PVA-based resin-water composition, plasticizers such as polyhydric alcohols such as ethylene glycol, glycerin, polyethylene glycol, diethylene glycol, and triethylene glycol, phenolic, amine-based, and the like, as long as the effects of the present invention are not impaired. Regular additives such as antioxidants, stabilizers such as phosphate esters, colorants, fragrances, extenders, defoamers, release agents, UV absorbers, inorganic powders, surfactants, etc. There is no problem. Moreover, you may mix other water-soluble resins other than PVA-type resin, such as starch, carboxymethylcellulose, methylcellulose, and hydroxymethylcellulose.
Furthermore, after biaxial stretching, it is preferable to perform heat treatment, and the temperature of such heat treatment is preferably selected to be lower than the melting point of the PVA resin, and particularly preferably 140 to 250 ° C. . When the heat treatment temperature is lower than the melting point by 80 ° C. or more, the dimensional stability tends to decrease and the shrinkage rate tends to increase. On the other hand, when the heat treatment temperature is higher than the melting point, the thickness variation of the film tends to increase. Moreover, it is preferable that heat processing time is 1 to 30 second, More preferably, it is 5 to 10 second.
In addition, for the purpose of further reducing the heat deformability, the biaxially stretched PVA-based resin film can be subjected to contact with an aqueous solution and drying as necessary. In the contact with the aqueous solution, an aqueous solution of usually 5 to 60 ° C., preferably 10 to 50 ° C. is used, and the contact time with the aqueous solution is appropriately selected according to the temperature of the aqueous solution, but industrially 10 to 10 ° C. Preferably it is 60 seconds.
Examples of the contact method with the aqueous solution include immersion in an aqueous solution, spraying of the aqueous solution, application of the aqueous solution, steam treatment, and the like, and these can be used in combination. After contact with the aqueous solution, industrially, it is preferable to remove the adhering water on the surface in a non-contact manner with an air shower or the like, and then to remove the moisture in a contact manner with a nip roll or the like. Examples of the type of dryer include a method of directly contacting a metal roll or a ceramic roll and drying, a method of using a non-contact type dryer, and the like.
When the obtained biaxially stretched PVA-based resin film is wound up again after being brought into contact with the aqueous solution and dried, the moisture content of the film is usually 3% by weight or less, preferably 0.1 to 2%. It is desirable to make it weight percent. If the amount of moisture is too large, the films tend to adhere to each other in the film roll, and there is a risk of problems such as damage to the film when unwinding for processing again. Thus, a biaxially stretched PVA resin film suitably used in the present invention is obtained.

  The thickness of the PVA resin film formed as described above is usually 10 to 70 μm, preferably 11 to 60 μm, and particularly preferably 12 to 50 μm. If the thickness is too thin, the gas barrier property tends to decrease, and if it is too thick, the moldability tends to decrease.

  And the film which comprises the storage bag of this invention consists of a film provided with the said PVA-type resin layer at least, Especially the said film is a multilayer film which consists of three or more layers, Comprising: The intermediate | middle layer is The PVA resin layer made of a stretched film of PVA resin is excellent in terms of gas barrier properties and film strength. As described above, it is more excellent in terms of tear strength and tensile strength that the stretched film of the PVA resin is a biaxially stretched film.

  As a layer other than the PVA resin layer in the multilayer film, for example, a film made of polyester represented by polyethylene terephthalate and polyethylene naphthalate, a polycarbonate film, a polyamide film made of nylon 6, nylon 66, etc., a polyvinyl chloride film, Polyvinylidene chloride film and polypropylene, low density polyethylene, linear low density polyethylene, low density polyethylene, medium density polyethylene, high density polyethylene, ethylene-vinyl acetate copolymer, ionomer, ethylene-propylene copolymer, ethylene- α-olefin (α-olefin having 4 to 20 carbon atoms) copolymer, ethylene-acrylate copolymer, polypropylene, propylene-α-olefin (α-olefin having 4 to 20 carbon atoms) N) Polyolefins such as copolymers, polybutenes, polypentenes, and other olefins or copolymers, cyclic polyolefins, or polyolefins in a broad sense such as those obtained by graft-modifying these olefins alone or copolymers with unsaturated carboxylic acids or esters thereof -Based resins, polystyrene resins, polyesters, polyamides, copolymerized polyamides, polyvinyl chloride, polyvinylidene chloride, acrylic resins, vinyl ester resins, polyester elastomers, polyurethane elastomers, chlorinated polyethylene, chlorinated polypropylene, and other thermoplastic resins Examples thereof include those made of a thermoplastic resin film such as a film made of polyolefin such as propylene-α-olefin random copolymer and ethylene-α-olefin random copolymer. The thermoplastic resin film may be an unstretched film or a uniaxial or biaxially stretched film. The thermoplastic resin film may be a film in which a metal such as aluminum, zinc or silica, an inorganic substance, or an oxide thereof is deposited.

  Then, a single or a plurality of the above films are laminated on both sides of the PVA resin film to form a target multilayer film. The thickness from the surface of the multilayer film to the PVA resin layer (that is, the thickness of the layer laminated on the PVA resin film) is usually in the range of 10 to 100 μm, preferably in the range of 40 to 90 μm. is there. Moreover, the total thickness of the said multilayer film is the range of 100-500 micrometers normally, and the storage bag of this invention should just be the thickness which shows the pressure | voltage resistant performance of 10 kPa or more, Preferably it is 14 kPa or more.

  In the multilayer film, as a method for adhering the films constituting the respective layers, for example, a urethane film or an isocyanate anchor coating agent is applied to the resin film, and the resin film is dry laminated on the surface thereof, or the molten heat Examples include a method of laminating between resin films by extrusion lamination of a plastic resin, a method of performing extrusion coating of a molten thermoplastic resin on the surface of the resin film, and dry laminating a thermoplastic polyurethane elastomer (TPU) film on the surface. . The thermoplastic polyurethane elastomer (TPU) film is commercially available as a film excellent in stretchability, moisture permeability, wear resistance, and chemical resistance obtained by extrusion molding of a thermoplastic polyurethane elastomer (TPU). From the viewpoint of applications, in particular, Silk Ron ES85 (urethane monolayer film, thickness 30 μm) and Silk Ron NES 85 (film with a polyethylene film separator, thickness 25 μm) manufactured by Okura Kogyo Co., Ltd. can be suitably used.

  For example, the multilayer film is composed of a polyethylene (PE) layer, a PVA resin layer, a TPU layer, and a PE layer in this order from the inside of the storage bag, from the viewpoint of gas barrier properties, flexibility, and the like. preferable. In addition to the above layer structure, the storage bag of the present invention may be formed by laminating PE layer / TPU layer / PVA resin layer / TPU layer / PE layer and TPU layer / PVA resin layer / TPU layer in this order. Can be used.

The storage bag of the present invention can be manufactured, for example, by joining the multilayer films by heat sealing to form a bag shape, and further providing a hydrogen gas injection part at least at one position on the surface. If this heat seal strength (peel strength of the heat seal portion) is at least 40 to 140 (N / 3 cm) or more, gas barrier properties, mechanical strength, and the like are good. Moreover, it is preferable that the bag which consists of the said multilayer film has a multilayer structure from viewpoints, such as mechanical strength and gas-barrier property.
In addition, the shape of the storage bag of the present invention includes a cube, a rectangular parallelepiped, a sphere, a pillow shape (a tube shape having a long side in the horizontal direction with respect to gravity), and the like. As a specific example, a rectangular parallelepiped, a cube, or a pillow-shaped bag is used, and a particularly preferable form is a pillow that can reduce installation space and assembly cost. In addition, as the structure of the hydrogen gas injection part, a normal gas injection part structure can be adopted. Specifically, for example, a hole of a desired size to be a gas injection port is formed in a bag, and packing is provided if desired. In combination, a gas connector made of SUS capable of connecting a gas injection nozzle to the hole is provided.

In addition, the capacity | capacitance of the storage bag of this invention is 0.3-10 m < ³ > normally when it presupposes the hydrogen gas collection | recovery in a normal hydrogen station, Preferably it is the range of 0.5-5 m < ³ >.
The weight of the storage bag of the present invention varies greatly depending on the layer structure of the constituent film, the capacity of the bag, and the presence or absence of the pipe frame or canvas as described above, but is lighter than conventional metal tanks. Yes, usually 4-20 kg. If it is light in weight, the installation location can be selected more freely than the conventional product. For example, it can be installed on the roof of a hydrogen station building.

In the storage bag of this invention, it is also possible to use together the member for providing the bag with a further function. For example, pipe frames may be fixed to the upper and lower parts of the storage bag, respectively, and both pipe frames may be connected to each other so as to be movable toward and away from each other. Furthermore, the entire storage bag may be covered with, for example, a canvas having a thickness of about 0.5 mm so as to be excellent in durability and the like.
In addition, it is preferable that a bellows portion can be formed at an arbitrary position on the canvas member, and the bellows portion expands and contracts according to the hydrogen gas capacity in the bag body. In particular, when a pipe frame and canvas are used in combination, the bag can be compressed by operating the pipe frame and the gas in the bag can be discharged.

  Further, the storage bag of the present invention is preferably used as a hydrogen gas storage bag used for in-vehicle fuel cell system, loss hydrogen recovery in a liquefied hydrogen storage tank, etc. in addition to those used in the hydrogen station as described above. Can do. It can also be used as a gas bag of helium, xenon, krypton, or the like.

  Next, a hydrogen gas supply / recovery system for a fuel cell vehicle (FCV) will be described as an example of a hydrogen gas supply / recovery system for a hydrogen vehicle using the storage bag of the present invention.

That is, in the hydrogen gas supply / recovery system for a fuel cell vehicle (FCV) of the present invention, as shown in FIG. 1, a high pressure hydrogen storage tank 2 is provided with a supply valve 4, a gas supply pipe 3, and a hydrogen gas filling nozzle 5. A hydrogen gas purge pipe 6 is connected in this order, and a gas purge pipe 6 is connected so as to branch the pipe path of the gas supply pipe 3, and a discharge valve 7 is provided in the middle of the gas purge pipe. In the gas filling device (hydrogen station facility) 10,
The hydrogen gas filling nozzle 5 is attached to a hydrogen gas receiving part 11 of a fuel cell vehicle (FCV) 9, and the tip of the gas purge pipe 6 is connected to the hydrogen gas injection part 8 of the storage bag 1 of the present invention,
In a state in which the supply valve 4 is opened, hydrogen in the high-pressure hydrogen storage tank 2 is filled in a hydrogen tank (not shown) of a fuel cell vehicle (FCV) 9. By closing and opening the discharge valve 7, the residual hydrogen gas in the pipe is collected in the storage bag 1.
The storage bag 1 may be provided in the hydrogen gas filling device 10 as indicated by the broken line in the drawing, or may be provided outside the hydrogen gas filling device 10.

  The normal pressure of the high-pressure hydrogen storage tank 2 in the pressure accumulator design (not shown) fixedly installed in the hydrogen gas filling device 10 is usually 30 to 90 MPa at the hydrogen station, and usually 10 to 40 MPa at the mobile hydrogen station. Yes, the design temperature is usually set to about -20 to 70 ° C. The capacity of the high-pressure hydrogen storage tank 2 is usually 200 to 300L. The high-pressure hydrogen storage tank 2 may be switched / replaced with another pressure-hydrogen storage tank as soon as there is no hydrogen, and hydrogen is reinjected into the high-pressure hydrogen storage tank 2 and used as it is. You may make it do.

  The gas supply pipe 3 and the gas purge pipe 6 are made of SUS316L (High Ni) from the viewpoint of corrosion resistance and the like, and usually have a diameter of 10 to 100 mm, preferably 10 to 30 mm, particularly preferably 10 to 20 mm. Those of the order are preferably used.

The supply valve 4 can control the gas supply to the FCV by its opening / closing operation, and the discharge valve 7 controls the supply of residual gas in the pipe into the storage bag 1 by the opening / closing operation. It can be.
The hydrogen gas filling nozzle 5 is equipped with a check valve, and when hydrogen gas is charged from the hydrogen gas receiving part 11 of the FCV by the pressure of the high-pressure hydrogen storage tank 2 and removed from the receiving part, A structure in which gas release is prevented by a check valve is preferable.

  In the hydrogen gas supply / recovery system, after supplying the hydrogen gas to the fuel cell vehicle (FCV) 9 with the supply valve 4 opened and the discharge valve 7 closed, the supply valve 4 is closed. At the same time, the discharge valve 7 is opened and the supply of hydrogen gas is stopped. By repeating this work, high-pressure filling (rapid filling) of hydrogen gas into individual FCVs becomes possible, and the residual gas in the piping can also be safely recovered in the storage bag 1. And by always discharging | emitting or consuming the said storage bag 1 in which the residual hydrogen gas accumulated, the hydrogen gas supply and recovery system for hydrogen vehicles of this invention can be operated continuously, Furthermore, the said storage bag Since it is lightweight, the above replacement work is also easy.

  The method of taking out hydrogen from the storage bag 1 in which residual hydrogen gas is accumulated as described above is not particularly limited. For example, a method of sucking out hydrogen gas in the bag by a pump or the like, The method of discharging | emitting hydrogen gas in the inside is mention | raise | lifted. In particular, in the method of applying pressure from the outside of the bag, as long as the bellows portion is provided on the side of the bag as described above, it is possible to apply pressure to the bag and discharge hydrogen gas by contracting that portion. It becomes.

  EXAMPLES Hereinafter, the present invention will be described more specifically with reference to examples. However, the present invention is not limited to the following examples unless it exceeds the gist. In the following description, “%” and “part” are based on weight unless otherwise specified.

[Example 1]
<Production of multilayer film>
From a hopper of a twin-screw extruder type kneader (screw L / D = 40) set at a jacket temperature of 60 to 150 ° C., polyvinyl alcohol (polymerization degree 1700, viscosity of 4% by weight aqueous solution 40 mPa · s, saponification degree 99. 7 mol%, sodium acetate content 0.3%, “GOHSENOL NH-17Q” manufactured by Nippon Synthetic Chemical Industry Co., Ltd.) and water at a polyvinyl alcohol / water weight ratio of 40/60 by a metering pump and kneaded. The discharge amount was 500 kg / hr.
This discharged material was immediately pumped to a single screw extruder (screw L / D = 30), kneaded at a temperature of 85-140 ° C., extruded from a T-die onto a 5 ° C. cast roll, and then heated at 90 ° C. with a hot air dryer. The film was dried for 2 seconds to prepare a polyvinyl alcohol film (thickness 150 μm) having a water content of 25%. Subsequently, the polyvinyl alcohol film was stretched 3.8 times in the MD direction, then stretched 3.8 times in the TD direction with a tenter, and then heat-fixed at 180 ° C. for 8 seconds to form a biaxially stretched PVA film (thickness 14 μm). Got. Using this biaxially stretched PVA film, dry lamination of each film was performed in the order of L-LDPE, biaxially stretched PVA film, TPU and L-LDPE, and an L-LDPE layer (80 μm) / biaxially stretched PVA layer ( 14 layer) / TPU layer (30 μm) / L-LDPE layer (80 μm) were laminated in this order to prepare a four-layer film.

<Production of storage bag>
A bag of 50 × 50 × 50 cm (cube, 0.125 m ³ ) is obtained by welding the obtained four-layer film so that the biaxially stretched PVA layer side is on the inner side of the bag and the overlapping portion of the film is welded with a width of 10 mm. (Hydrogen gas storage bag) was produced.
That is, a hydrogen gas storage bag having a layer structure in which an L-LDPE layer (80 μm) / biaxially stretched PVA layer (14 μm) / TPU layer (30 μm) / L-LDPE layer (80 μm) are laminated in this order from the inside of the bag. Was made.

[Comparative Example 1]
<Production of multilayer film>
L-LDPE, aluminum-deposited EVOH, TPU, and L-LDPE are laminated in order for each film, and L-LDPE layer (80 μm) / aluminum-deposited EVOH layer (12 μm) / TPU layer (30 μm) / L-LDPE layer A four-layer film laminated in the order of (80 μm) was produced.

<Production of storage bag>
In place of the four-layer film of Example 1, the four-layer film produced above was prepared from the inside of the bag by an L-LDPE layer (80 μm) / aluminum-deposited EVOH layer (12 μm) / TPU layer (30 μm) / L-LDPE layer ( 80 μm). Other than that was carried out similarly to Example 1, and produced the hydrogen gas storage bag.

  The following measurements and evaluations were performed on the storage bags of Examples and Comparative Examples thus obtained. The results are shown in Table 1 below.

[Bending test of multilayer film (1)]
The multilayer film constituting the storage bag was bent 5 times under the following conditions in a gelbo flex tester (manufactured by Rigaku Corporation) at 23 ° C. and 50% RH. And before and after bending 5 times, the oxygen permeability (23 degreeC, 65% RH conditions) of the film was measured according to the method as described in JISK7126 (isobaric method).
Bending condition: 440 ° C. Twist (9.98 cm) + Straight (6.35 cm)
Temperature: -15 ° C

[Bending test of multilayer film (2)]
The multilayer film constituting the storage bag was manually hand-bent 50 times with both ends fixed. And the hydrogen permeability coefficient (40 degreeC conditions) of the film before and after bending of a hand pad was measured in the case of hydrogen pressure 0.3MPa and 0.7MPa.

From the results of Table 2 above, in Comparative Example 1 using the multilayer film constituting the storage bag of Comparative Example 1, the hydrogen permeability coefficient “after bending” is about twice the hydrogen permeability coefficient “before bending”. A high number was shown. From this, it was confirmed that the aluminum vapor deposition layer was cracked by a relatively low-level bending test such as a hand grip, and that hydrogen permeability with a small molecular size could not be suppressed only by the EVOH layer.
In Example 1 using the multilayer film constituting the storage bag of the present invention, the hydrogen permeability coefficient “after bending” showed a low value of about ½ of the hydrogen permeability coefficient “before bending”. . From this, it was confirmed that no crack occurred in the film in the bending test of hand-tacking. In addition, the reason why the hydrogen permeability coefficient showed a lower value is presumed that the hydrogen gas used in the hydrogen permeability test before bending reduced the water content of the PVA layer in the multilayer film and improved the hydrogen gas barrier properties. Is done.

[Storage bag gas discharge durability test (1)]
A test was conducted to determine whether or not the hydrogen gas storage bag could be durable for repeated gas injection and discharge. In such a gas-filled discharge endurance test, nitrogen gas, which is a gas having a low moisture content, which is substantially the same as the hydrogen gas actually used as a model gas of the hydrogen gas actually used, was used due to the circumstances of reducing experimental costs.
Under the condition of 40 ° C., the storage bag was filled with 100 L of nitrogen gas, and then released (depressurized) until the internal volume reached 10 L. Such gas filling and releasing operation was repeated 400 times.

<Gas permeability measurement>
100 L of high-purity helium is introduced into the storage bag before and after the repeated gas filling and releasing operation, and after exposure to atmospheric pressure air (1 atm) at 40 ° C., the air-derived gas concentration in the bag is measured with a gas chromatograph. Permeability of gas entering the bag from the outside of the bag by the product of the air-derived gas concentration and the volume of helium in the bag [the total volume of gas (air-derived gas (nitrogen, oxygen)) entering the bag from the outside of the bag] And the transmittance (cc / m ² · day · atm) calculated] was calculated.

From the results of Table 3 above, it can be seen that the storage bag of Example 1 has a lower air-derived gas permeability before and after the gas-filled discharge operation than the storage bag of Comparative Example 1. Further, in the storage bag of Example 1, the gas barrier layer is dried in the gas filling / depressurization cycle, so that the gas barrier property is improved after the gas filling and releasing operation. Even in Comparative Example 1, although the improvement of the air-derived gas barrier property is observed after the gas filling / releasing operation, the bag is fatigued by repeating the gas filling / releasing operation, and the aluminum vapor deposition layer, which is one layer of the bag film, cracks. The gas barrier property improving effect as in Example 1 was not obtained.
From these results, it can be seen that the gas barrier property of the storage bag of the present invention does not decrease even when subjected to bending in the gas filling and releasing operation, but rather the gas barrier property improves as the operation is repeated.

[Storage bag gas discharge durability test (2)]
The gas-sealed release operation was repeated 100 times under the condition of −15 ° C. Other than that, the air-derived gas permeability was measured in the same manner as in the above-mentioned “Gas enclosure discharge durability test for storage bag (1)”.

  From the results of Table 4 above, it can be seen that the storage bag of Example 1 has a lower permeability of the air-derived gas before and after the gas filling and discharging operation than the storage bag of Comparative Example 1. And it turns out that the gas barrier effect appears more remarkably than the result of previous Table 3. That is, it is considered that the gas barrier property was improved because the drying of the gas barrier layer further progressed at a low temperature (−15 ° C.). In Comparative Example 1, since the aluminum vapor deposition layer was cracked at −15 ° C., the effect of improving the gas barrier property as in Example 1 was not obtained.

From the above results, in Comparative Example 1 using an aluminum vapor-deposited EVOH film as the intermediate layer, the initial gas permeability is good for hydrogen having a molecular size smaller than that of oxygen molecules, but the gas after the bending test. It can be seen that the permeability is lowered to a gas barrier property level corresponding to the free volume pore size (0.461 nm) of the original amorphous part of EVOH.
On the other hand, in Example 1 using a PVA film as the intermediate layer, it can be seen that there is little increase in hydrogen permeability after the bending test.

  Therefore, the storage bag of Example 1 can suppress the intrusion of air-derived gas into the storage bag, and can suppress the state in which the amount of air-derived gas mixed is 0.1% or more for a long period of time. This leads to safety and quality maintenance when reused as fuel cell hydrogen. It can be understood that this effect is practical without any significant decrease in the course of use, and without leakage of hydrogen gas.

  The hydrogen gas storage bag of the present invention is lightweight, excellent in storing hydrogen gas, and excellent in operability, and is used in a hydrogen station, as well as in-vehicle fuel cell system, loss hydrogen recovery in a liquefied hydrogen storage tank It can preferably be used also as a hydrogen gas storage bag used for the like. The hydrogen gas supply / recovery system of the present invention is suitable for a fuel cell vehicle (FCV), but can be used for other hydrogen gas supply applications.

DESCRIPTION OF SYMBOLS 1 Storage bag 2 High pressure hydrogen storage tank 3 Gas supply piping 4 Supply valve 5 Hydrogen gas filling nozzle 6 Gas purge piping 7 Release valve 8 Hydrogen gas injection part 9 Fuel cell vehicle 10 Hydrogen gas filling device

Claims (6)

A hydrogen gas storage bag comprising a film having at least a polyvinyl alcohol-based resin layer, wherein the oxygen permeability in a gelbo flex tester after bending the film five times is 0.03 cc / m ² · day · atm or less. A hydrogen gas storage bag, wherein the storage bag has a permeability of air-derived gas of ² cc / m ² · day · atm or less when exposed to 1 atm of air.   2. The hydrogen gas storage bag according to claim 1, wherein the film constituting the storage bag is a multilayer film composed of three or more layers.   The hydrogen gas storage bag according to claim 2, wherein the intermediate layer of the multilayer film constituting the storage bag has a polyvinyl alcohol resin layer made of a stretched film of polyvinyl alcohol resin.   The hydrogen gas storage bag according to any one of claims 1 to 3, wherein the polyvinyl alcohol-based resin layer is made of a biaxially stretched film.   The film which comprises the said storage bag is laminated | stacked in order of a polyethylene layer, a polyvinyl alcohol-type resin layer, a thermoplastic polyurethane elastomer layer, and a polyethylene layer from the inner side of a storage bag, Any one of Claims 1-4. The hydrogen gas storage bag according to item. A supply valve, a gas supply pipe, and a hydrogen gas filling nozzle are connected to the high-pressure hydrogen storage tank in this order, and a gas purge pipe is connected to branch the piping path of the gas supply pipe. In the hydrogen gas filling device constructed and provided with a discharge valve in the middle of
The hydrogen gas filling nozzle is attached to a hydrogen gas receiving portion of a hydrogen vehicle, and a tip of the gas purge pipe is connected to the hydrogen gas storage bag according to any one of claims 1 to 5,
With the supply valve opened, the hydrogen in the high-pressure hydrogen storage tank is filled into the hydrogen tank mounted on the hydrogen vehicle, and when the filling is completed, the supply valve is closed and the discharge valve is opened. A hydrogen gas supply / recovery system for a hydrogen vehicle, wherein the residual hydrogen gas is recovered in the storage bag.

Images