JP2007315546A - Hydrogen storage vessel and hydrogen absorption and desorption device - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a hydrogen storage vessel and a hydrogen storage device of high efficiency in heating a storage body for hydrogen absorption and desorption, a simple structure and light weight without deteriorating a circulation property of gas. <P>SOLUTION: The hydrogen storage vessel 100 fluidally filled with a hydrogen storage body 30 is provided with a fluidizing part filled with a plurality of heat accumulation mediums 10 and including a mixing blade 41 and a mixing shaft 40 mixing and fluidizing the hydrogen storage body and the heat accumulation mediums, a heating part 60 heating the hydrogen storage body and the heat accumulation mediums, and a hydrogen outlet and inlet part installed to enable to be ventilated with the outside. <P>COPYRIGHT: (C)2008,JPO&INPIT

Description

The present invention relates to a hydrogen storage container and a hydrogen storage / release device including a hydrogen storage body that stores and releases hydrogen.

2. Description of the Related Art Conventionally, hydrogen storage containers that store and release hydrogen by heating a hydrogen storage body such as a hydrogen storage alloy filled in the container from the outside of the container are known. The hydrogen storage body is a powder that can occlude or release hydrogen when activated by being heated above a certain temperature.
On the other hand, a hydrogen storage tank has been proposed in which a heat medium pipe and a fin portion extending from the heat medium pipe are fitted in a container in order to improve the heat conductivity to the hydrogen storage body (for example, Patent Documents). 1). In such a storage tank, the hydrogen storage metal is stored in a space defined by the outer cylinder member, the heat medium pipe, and the fin, and the heat medium flows through the heat medium pipe inside the container, and passes through the fin from the heat medium pipe. Heat is transferred to the hydrogen storage metal.
Patent Document 2 discloses an invention in which a heat medium pipe is arranged around a hydrogen storage body so that hydrogen can be sufficiently brought into contact during re-storage of hydrogen.
Japanese Unexamined Patent Publication No. 6-281097 JP 2002-364944 A

However, a general hydrogen storage body is powder, and heat conductivity is poor even when heated from outside the container, and it is difficult to uniformly heat the hydrogen storage body in the container. In particular, the larger the capacity of the container, the more difficult it is to uniformly heat the hydrogen storage body.

On the other hand, like a container exemplified in Patent Document 1, a heat medium pipe is provided inside a hydrogen storage container, a thermal solvent is caused to flow inside the heat medium pipe, and a heat conduction fin provided in connection with the heat medium pipe is provided. There is a method for promoting thermal diffusion, but in this case, the structure of the container becomes complicated, and the powder of the hydrogen storage body is not suitable for efficient filling. Moreover, when the heat medium pipe and the heat conducting fin connected to the heat medium pipe are provided, the weight of the entire container increases.

In addition, in the hydrogen storage container, it is necessary to ensure gas flowability because hydrogen is stored in the hydrogen storage body and hydrogen is released from the hydrogen storage body. If provided, the gas flow is hindered. In particular, since the inorganic complex-based hydrogen storage body has a lower thermal conductivity than the conventional alloy-based hydrogen storage body, the efficiency of heating the storage body for absorbing and releasing hydrogen is further reduced. Here, the powder-type hydrogen storage body is composed of hydrogen storage alloys such as La—Ni and Ti—Cr—V, metal hydrides such as MgH 2 and AlH 3, alanate materials such as NaAlH 4, lithium-nitrogen or Lithium-boron materials and carbon materials such as graphite and carbon nanotubes can be used, and are not particularly limited. Furthermore, the hydrogen storage body of the inorganic complex-based powder uses a mixed part and a reaction product of an alkali metal or alkaline earth metal metal amide and the metal hydride. The body tends to consolidate, hinders efficient heat transfer, and the hydrogen storage body's original hydrogen storage / release ability cannot be fully exploited.

It is an object of the present invention to provide a hydrogen storage container and a hydrogen storage device that have high efficiency in heating a storage body for absorbing and releasing hydrogen, and have a simple structure and light weight without impairing gas flowability. .

In order to achieve the above object, a hydrogen storage container according to the present invention is a hydrogen storage container filled with a hydrogen storage body so as to be flowable, and further filled with a plurality of heat storage media, and the hydrogen storage body and the heat storage medium. A fluidizing section including a stirring blade and a stirring shaft for mixing and fluidizing the medium, a heating section for heating the hydrogen storage body and the heat storage medium, and a hydrogen inlet / outlet section that is attached to the outside so as to be ventilated. A hydrogen storage container.

Furthermore, the hydrogen storage / release device according to the present invention occludes hydrogen while driving the fluidizing section at a predetermined temperature by a temperature-controllable heating section, and further stores hydrogen from the hydrogen inlet / outlet section at a predetermined temperature. A hydrogen absorbing / releasing device that discharges, wherein the combustion energy or chemical reaction energy of the released hydrogen is used to drive the fluidized portion.

The heat storage medium of the present invention of the present invention usually has a capsule structure, has good heat conduction on the surface, and can store heat inside. Heat conduction from the heating unit to the hydrogen storage body can be improved via the heat storage medium. In addition, since the hydrogen storage body filled in the container and the fluidizing unit including the stirring blade and the stirring shaft for stirring the heat storage medium are circulated in the container together with the heat storage medium, the entire hydrogen storage body Can be mixed uniformly. By this mixing, heat conduction becomes more efficient. In the hydrogen storage body, since the heat storage medium plays the role of a mixed medium, heat is easily transmitted efficiently to the entire hydrogen storage body. Furthermore, since the whole is fluidized, it is possible to prevent consolidation, and it is possible to prevent inhibition of hydrogen storage and release reaction due to consolidation. In addition, this makes it possible to improve hydrogen gas permeability while maintaining high thermal conductivity.

Moreover, it can be set as a simple structure compared with the structure of the internal heating system which passes a heat-medium pipe | tube through the whole container inside. In addition, the heating method can adopt an external heating method rather than internal heating using a heat medium tube or the like, and even when subjected to an impact, the heat medium tube is damaged and the heating medium leaks. Absent.

In addition, it is preferable that the hydrogen storage container is formed in a substantially cylindrical shape or a substantially polygonal column. Thereby, a plurality of hydrogen storage containers can be arranged and used as an aggregate, and a hydrogen storage device can be produced according to the required capacity. Moreover, the hydrogen storage container can be juxtaposed compactly when the external shape is a polygonal column. In addition, the production cost can be reduced by mass production as a unit.

Moreover, it is preferable that the hydrogen storage device of the present invention includes a hydrogen inlet / outlet portion that is attached so as to be able to vent from the outside, and a temperature control portion that controls the temperature of the heating portion. Moreover, the flow path formation part which forms the flow path which distribute | circulates hydrogen is provided in the container exterior.

The hydrogen storage container of the present invention can efficiently transfer heat from the heating unit to the hydrogen storage body and can prevent inhibition of hydrogen release reaction.

Moreover, since an external heating system can be employ | adopted, it can be set as a simple structure compared with the structure of the internal heating system which passes a heat-medium pipe | tube through the whole container inside at this time. In addition, even if the heating method is an internal heating method using a heat medium pipe or the like, the heating part can be limited to a part in the container, and if this part is solid, even when it receives some impact Inconvenience that the heating medium leaks does not occur.

Moreover, it is preferable that the hydrogen storage container is formed in a substantially cylindrical shape and a substantially polygonal column in outer shape. Thereby, a plurality of hydrogen storage containers can be arranged and used as an aggregate, and a hydrogen storage device can be produced according to the required capacity. Further, when the outer shape is a substantially polygonal column, it can be filled densely. In addition, the production cost can be reduced by mass production as a unit.

Hereinafter, embodiments of the present invention will be described with reference to the drawings.

FIG. 1 is a cross-sectional view of the hydrogen storage container 100. The hydrogen storage container 100 is a horizontal type in which the heat storage medium 10 is filled in the filling container 20 together with the hydrogen storage body 30 so as to be flowable, and includes a fluidizing unit 40 including a stirring blade 41 and a stirring shaft 42 for stirring both. . The part where the stirring shaft 42 and the filling container 40 are in contact with each other preferably has a mechanical seal mechanism, a Wilson seal mechanism, a shaft seal mechanism, or the like that does not cause gas leakage even under hydrogen storage pressure or discharge pressure. Furthermore, a hydrogen inlet / outlet part 50 mounted so as to be able to ventilate to the outside, a heating part 60 for heating the hydrogen storage body 30, and a temperature control part (not shown) for controlling the temperature of the heating part are provided. Is preferred. Further, the flow pipe 51 through which hydrogen is circulated is connected to the filling container 20 so as to circulate hydrogen from the filter section 50, thereby forming a hydrogen inlet / outlet section. Filling ports for the heat storage medium 10 and the hydrogen storage body 30 are provided on the container lid 21 and the container side surface. Alternatively, the filling container may be filled in a state in which a part of the container lid 21 is removed without specially providing a filling port. A plurality of hydrogen inlet / outlet portions can be provided, and the hydrogen flow path can be adjusted by dividing the functions into the outlet portion and the inlet portion. As the heating unit 60, an electrothermal heater is provided outside the filling container.

The heat storage medium 10 is preferably a capsule structure enclosing a heat storage material or a metal sphere.
(1) Shape, etc. FIG. FIG. 3A shows a core-shell capsule type heat storage medium. A heat storage material is enclosed in an outer shell. FIG. 4 schematically shows the manufacturing process. This is because a hemispherical shell or a spherical shell with an open top is filled with a heat storage material as a core (shown in FIG. 4B), and the opening is enclosed (FIG. 4C). ), FIG. 4 (d)). In this case, the heat storage material may be heated at a temperature equal to or higher than the melting point and filled as a molten liquid, or may be filled with a powder or lump. At this time, it is preferable to provide a space in the upper portion of the shell so that the volume expansion accompanying the phase change of the core portion can be absorbed. Next, after the heat storage material is filled, the open portion of the shell portion is closed using a brazing material or solder. When the upper part of the capsule is closed with a lid, the lid portion of the shell and the main body portion are joined with a brazing material or the like.

FIG. 3B shows a medicine capsule type heat storage medium. An outline of the manufacturing process is shown in FIG. The process order is indicated by arrows. Pipes are used to form the shell and pre-filled with heat storage material. The heat storage material is sealed by compressing, constricting, or pulling from both sides of the cut part of the pipe. The diameter of the corresponding part of the pipe may be narrowed in advance and filled with a heat storage material serving as a core. Next, the portion with the reduced diameter is cut, and the hole is sealed with a brazing material or solder.

The thickness of the core and shell may be changed as appropriate. In the core-shell capsule type of FIG. 3A, for example, a spherical shape having a diameter of 5 to 50 mm and a thickness of about 1 to 10 mm is preferably used. In FIG. 3 (b), in the drug capsule type, a roughly cylindrical shape having a circular bottom surface with a diameter of 5 to 50 mm and a length of 20 to 50 mm is preferably used. In the spherical shape of FIG. 3C, a metal sphere such as aluminum, an alloy thereof, or copper is used.

(2) The material of the shell, such as material, is used properly according to whether the heating temperature of the hydrogen storage body is 100 ° C or lower or 100 ° C or higher. When the heating temperature is 100 ° C. or lower, it is possible to use a synthetic resin shell (for cooling and heating, etc.). However, for example, when a Li-Mg-NH-based hydrogen storage body (150 to 200 ° C. heating) is used, 100 ° C. or higher is required, so the synthetic resin has a problem in heat resistance. A metal shell such as aluminum, Al alloy, or copper is preferable in terms of heat resistance and thermal conductivity. Moreover, it is preferable to use a low-melting-point alloy (melting point of about 160 to 210 ° C.) as the filling material to fill the core. For example, use Sn-Pb42-Cd18 alloy (melting point 160 ° C) when using at 150 ° C, and Sn-Ag3.5-Bi0.5-In8 alloy (melting point 204 ° C) when using at 200 ° C. Can do. As the bonding material used for shell sealing, aluminum / wax, solder for aluminum, copper brazing or the like is preferably used.

(3) Thermal conductivity
The Li-Mg-NH hydrogen storage material has a thermal conductivity of 0.2 W / mK (in 1 MPa of hydrogen: 0.5 W / mK), metal aluminum: 236 W / mK, metal copper: 390 W / mK, and hydrogen storage Since the thermal conductivity of the material is much smaller than that of the shell metal, the heat energy from the heat exchanger cannot be transferred efficiently. However, if a heat storage medium with higher thermal conductivity than the hydrogen storage body is used, the heat energy from the heating part is once absorbed by the shell of the material with good heat conduction, and the phase transition material (here, solid / liquid phase) in the core part. By transferring the heat to the hydrogen storage material while flowing, the heat energy can be efficiently transferred to the entire hydrogen storage material. The phase change material is, for example, a low melting point alloy (for example, Sn—Pb42—Cd18 alloy). Hydrocarbons such as paraffinic compounds having a large latent heat (for example, those having 14 to 16 carbon atoms) and inorganic hydrated salts (for example, CaCl 2 · 6H 2 O and NH 4 Al (SO 4) 2 · 12H 2 O) can be suitably used.

When the filling container is heated from the outside, a metal container having good thermal conductivity is often used, and an aluminum or SUS container can be selected as appropriate depending on the use pressure and temperature. The material and shape of the container are not particularly limited as long as the material and shape can withstand the pressure when the hydrogen storage body 30 stores hydrogen. Even in the case of a pressure increase due to abrupt release during hydrogen release, the strength of the container is sufficient and safety can be ensured. In addition, since the filling container 41 is heated, a container with little deformation or alteration is used even when the temperature rises and falls at the operating temperature. It is not limited as long as it is a metal, and two or more kinds of alloys may be used. In particular, in the case of the external heating method, from the viewpoint of heat conduction, the heat conductivity of copper is 403 W / mK, the heat conductivity of aluminum is 236 W / mK, and copper and aluminum have high heat conductivity. Further, the density of aluminum is 2.70 × 10 ⁻³ kg / m ³ , the density of magnesium is 1.74 × 10 ⁻³ kg / m ³ , and aluminum and magnesium are low in density. In view of these excellent characteristics, a metal mainly composed of copper, aluminum, or magnesium may be used. Furthermore, the density of copper is as high as 8.96 × 10 ⁻³ kg / m3, while the thermal conductivity of magnesium is as low as 157 W / mK. Therefore, considering the balance between thermal conductivity and density, aluminum is the main component. A metal as a component is also preferable.

As shown in FIG. 1, the shape of the filling container is a cylindrical shape in which the stirring shaft 42 passes through the center of the bottom surface. As the stirring blade, a helical blade, a paddle blade, a marine propeller blade, a turbine blade, an anchor blade, or the like can be used. Helical blades, paddle blades, and marine propeller blades have a function of fluidizing the object to be stirred in a certain direction, and have an effect of mixing the heat storage medium and the hydrogen storage body over a wide range to close contact. Turbine blades and anchor blades have little effect of fluidizing the material to be stirred, but the filling vessel can be provided with a so-called “baffle plate” to promote mixing. This is to prevent so-called “accompaniment”. Even helical wings, paddle wings, and marine propeller wings can promote mixing by partially blocking the flow path and creating turbulent flow. In addition, the hydrogen storage medium and the heat storage medium can be smoothly filled by mixing or individually filling the filling container while rotating the stirring shaft.

The hydrogen inlet / outlet section includes an opening on the bottom surface or side surface of the filling container, and a filter 50 and a flow pipe 51 as necessary. When the heating temperature is as high as 150 to 200 ° C., heat resistance is required for the filter 50, and therefore, a metallic sintered filter is preferably used. The filter prevents the hydrogen storage body and the heat storage medium from being discharged out of the container, and allows only the gas that is hydrogen gas to pass through. Further, it is possible to prevent the solid matter from being brought into the filling container during the hydrogen storage. The flow pipe can be fitted with a safety valve.

The heating unit 60 is connected to a temperature control unit (not shown). Further, a power source (not shown) is connected. The heating unit 60 is provided with not only a member that heats the hydrogen storage body 30 from the outside of the container through the outer wall of the container as described above, but also a fixing member for heat conduction connected to the heater in the container. The thing which heats a hydrogen storage body by heating is also included. The heating unit 60 has a function of heating to a temperature of 80 ° C. or higher, and is preferably capable of heating to 300 ° C. In order to efficiently store and release hydrogen, the temperature is adjusted to 100 ° C. to 300 ° C. according to the characteristics of the hydrogen storage material used.

When the hydrogen storage body 30 is heated by the heating unit 60, the function of occluding or releasing hydrogen of the hydrogen storage body 30 is activated, so that hydrogen can be stored and released quickly. Furthermore, the heating unit 30 may be equipped with a temperature control unit that is mounted on the filling container 20 and includes a thermocouple (not shown) for measuring the internal temperature and a general temperature controller of the thermocouple.

Next, the operation of the hydrogen storage container 100 of FIG. 1 will be described. The hydrogen storage body 30 and the heat storage member 10 are filled in the filling container 20 so as to be flowable, and there is a void in the upper part of the container. When storing hydrogen gas in the hydrogen storage container 100, the heating unit 60 provided outside is controlled to a predetermined storage temperature, and the hydrogen storage body 30 and the heat storage member 10 are stirred by the stirring blade 41 while rotating the stirring shaft 42. Are mixed and stirred. The hydrogen storage body 30 and the heat storage member 10 are mixed and stirred on the spot. Maintain the temperature sufficiently to exhibit the hydrogen storage function. Heat is transferred from the heating section to the heat storage member and the hydrogen storage body close to the inner wall of the container. The heat transferred to the heat storage member further transfers to the hydrogen storage body in contact with or close to the heat storage member. And it will be transmitted to the hydrogen storage body 30 of the whole container uniformly and rapidly by stirring and fluidization. By selecting a stirring blade such as a helical blade, a paddle blade, or a marine propeller blade, it is particularly preferable to circulate in the container in the direction of the arrow shown in the figure. The heat storage action of the heat storage body is as described above. Next, hydrogen gas is pumped into the hydrogen storage container 100 from the hydrogen circulation pipe by a compressor (not shown) connected to the circulation pipe, and is stored in the hydrogen storage body 30. On the other hand, in the case of releasing hydrogen gas from the hydrogen storage container 100, first, the heating unit 60 is controlled to a predetermined temperature for releasing hydrogen, and the hydrogen storage body 30 is heated via the heat storage member 10 to sufficiently release hydrogen. Maintain the temperature at which Thus, the hydrogen gas is released from the hydrogen storage body, and the hydrogen gas is sent to the gas flow pipe 51.

FIG. 2 is a perspective view of a stationary hydrogen storage container. It becomes another embodiment of the hydrogen storage container which concerns on this invention. In this type, the rotary shaft 40 is set up almost vertically, and filling is performed by providing a gap in the upper part of the container, and fluidization is performed such that the hydrogen storage body 30 and the heat storage member 10 are pulled upward while mixing. When the hydrogen storage body 30 and the heat storage member 10 flow along the wall of the container 20, more efficient circulation and heat exchange can be realized.

Further, when the hydrogen storage container is mounted on a moving body such as an automobile using a hydrogen engine or a fuel cell, as described above, while the fluidizing unit is driven at a predetermined temperature by the heating unit capable of temperature control. A hydrogen storage / release device that stores hydrogen and further releases hydrogen from the hydrogen inlet / outlet portion at a predetermined temperature, and uses driving energy from a moving body to drive the fluidized portion. For example, as shown in FIG. 6, a part of the rotational force from the wheel shaft of the automobile can be taken out to drive the stirring shaft of the fluidized part. Thus, it is possible to realize a hydrogen absorption / release device characterized by using the hydrogen combustion energy or the electric energy generated by a chemical reaction at the electrode of hydrogen and oxygen. Thus, the mobile body on which the hydrogen storage container is mounted is not limited to a fuel cell vehicle, and may be a hydrogen engine vehicle. The mobile body includes vehicles such as automobiles and motorcycles, ships, and airplanes.

The hydrogen storage container 100 can also be used in hydrogen supply devices mounted on fuel cell vehicles, buffer tanks for stationary fuel cells, and storage container systems for hydrogen stations. It can be applied to all hydrogen storage devices.

It is sectional drawing which shows embodiment of the hydrogen storage container which concerns on this invention. It is a perspective view which shows another embodiment of the hydrogen storage container which concerns on this invention. The schematic diagram of 3 types of thermal storage media. It is a schematic diagram which shows the manufacturing method of a core-shell capsule type | formula thermal storage medium. It is a schematic diagram which shows the manufacturing method of a medicine capsule type heat storage medium. It is a schematic diagram which shows embodiment of the hydrogen absorption / release apparatus which concerns on this invention.

Explanation of symbols

100, 110; hydrogen storage container
120; Hydrogen absorption and desorption equipment
200; mobile
210; Drive unit
220; Fuel cell
10; Thermal storage medium
20; Filling container
21; Container lid
30; Hydrogen storage
40; stirring shaft
41; stirring blade
50; filter
51; Hydrogen distribution pipe
60; heating unit
70; Bearing (mechanical seal)

Claims (2)

A hydrogen storage container filled with a flowable hydrogen storage body,
Furthermore, it is filled with a plurality of heat storage media,
A fluidizing section including a stirring blade and a stirring shaft for mixing and fluidizing the hydrogen storage body and the heat storage medium;
A heating unit for heating the hydrogen storage body and the heat storage medium;
A hydrogen inlet / outlet part that is externally ventilated,
A hydrogen storage container comprising: A hydrogen absorption / desorption device that occludes hydrogen while driving the fluidizing unit at a predetermined temperature by the heating unit capable of temperature control, and further releases hydrogen from the hydrogen inlet / outlet unit at a predetermined temperature. A hydrogen absorption / release apparatus characterized by using combustion energy or chemical reaction energy of the released hydrogen to drive the conversion.

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