JP4348781B2 - Hydrogen gas storage method and storage device - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a method for storing hydrogen.
[0002]
[Prior art]
Conventionally, as a hydrogen storage method, there are a storage method of pressurizing to a high pressure, a storage method of cooling to a very low temperature and liquefying, and a method of storing in a hydrogen storage alloy.
According to such a storage technique, the amount of hydrogen gas stored can be increased as compared with storage at normal temperature and normal pressure.
[0003]
However, the above conventional hydrogen gas storage methods have the following problems.
That is, in the method of storing hydrogen gas under pressure, the hydrogen gas is pressurized to several hundred atmospheres, so that the energy cost is high and a sufficient storage density cannot be obtained.
In addition, in the method of cooling hydrogen gas to a very low temperature and liquefying and storing it, the energy cost for producing the cryogenic temperature is high.
[0004]
Further, although the hydrogen storage alloy has a large storage amount per unit volume, the storage amount per unit weight is small because the alloy weight is large.
[0005]
[Problems to be solved by the invention]
An object of the present invention is to provide a hydrogen gas storage method capable of lowering the storage pressure and increasing the storage temperature with respect to the conventional storage method.
[0006]
[Means for Solving the Problems]
In order to achieve the above object, according to the present invention, by cooling the hydrogen gas in the presence of the adsorbent, the temperature is higher than the liquefaction condition of the hydrogen gas in the absence of the adsorbent. A hydrogen gas storage method characterized by generating liquefied hydrogen gas is provided.
[0007]
DETAILED DESCRIPTION OF THE INVENTION
As a result of studying a more efficient storage method of hydrogen gas, the present inventor has found that when hydrogen gas is cooled in the presence of an adsorbent, the temperature is higher than the liquefaction condition of hydrogen gas in the absence of the adsorbent. It was also found that hydrogen gas liquefies at low pressure.
The reason why the liquefaction temperature of hydrogen shifts to the high temperature side due to the coexistence of the adsorbent has not yet been clearly clarified, but hydrogen is liable to liquefy in the pores of the adsorbent. In this case, hydrogen liquefied at a temperature higher than the normal liquefaction temperature overflows from the pores, and liquefaction occurs outside the adsorbent despite the temperature being higher than the normal hydrogen liquefaction conditions. Conceivable.
[0008]
Hydrogen has two types of states, ortho hydrogen and para hydrogen, due to the relationship between spin angular momentum. Since parahydrogen has less rotational energy, all molecules convert to parahydrogen at low temperatures. Since conversion to parahydrogen hardly occurs, a magnetic substance such as iron oxide or chromium oxide is used as a catalyst. Thereby, liquefaction can be promoted.
[0009]
Further, by supporting or contacting a metal or a compound capable of dissociating hydrogen gas molecules in an atomic form on the adsorbent, storage at a higher temperature and a lower pressure becomes possible. As said metal or compound, metals, such as Pt and Pd, or these compounds can be used.
[0010]
【Example】
[Example 1]
FIG. 1 shows an apparatus for liquefying hydrogen gas according to the present invention. In the illustrated apparatus, a granular adsorbent 12 is accommodated inside a glass pressure vessel 10, and a resin cover 14 is provided outside the pressure vessel 10 via an air layer 15 to transfer heat. It is designed to be uniform. The outer side of the cover 14 is further covered with a refrigerant container 16, and a space between the cover 14 and the refrigerant container 16 is filled with a refrigerant 18 such as liquid helium. The temperature of the adsorbent is measured by the thermocouple 20, and the pressure inside the pressure vessel 10 is measured by the pressure gauge 22. The introduction of hydrogen gas is controlled by opening and closing the valve 24, and exhaust and hydrogen supply are performed via the pipe 26.
[0011]
0.5 g of activated carbon (“MAXSORB” manufactured by Kansai Thermal Engineering Co., Ltd., specific surface area of 3000 cm ² / g) is charged as the adsorbent 12 in the pressure vessel 10, and the inside of the pressure vessel 10 is evacuated by a vacuum pump (not shown). Then, hydrogen gas was introduced and maintained at 1 atm, and the refrigerant was supplied to the refrigerant container 16 for cooling. The temperature at which the hydrogen gas was liquefied was measured as the liquefaction temperature. The liquefaction was detected visually. For comparison, the same operation was performed except that the activated carbon was not charged.
[0012]
As a result, when activated carbon was not charged, it was liquefied at 20K, but when activated carbon was charged according to the present invention, it was liquefied at 25K.
In order to promote the conversion to parahydrogen, when the activated carbon was supported or contacted with a magnetic material such as iron oxide or chromium oxide as a catalyst, it could be liquefied more stably.
[0013]
In this embodiment, activated carbon is used as the adsorbent, but FSM, zeolite, and metal complex can also be used.
Next, the hydrogen adsorption amount when the pressure in the pressure vessel 10 was kept constant at 1 atm and the temperature of the activated carbon was 25K was measured. The amount of adsorption was measured by using the internal pressure of the pressure vessel 10 as the equilibrium pressure at the temperature at that time, and recovering hydrogen gas by water replacement.
[0014]
As a result, 820 was obtained as the liquid hydrogen adsorption amount. This is a value larger than 800 of the liquid hydrogen density at 20K in a normal state where no adsorbent is present.
In the measurement of the amount of adsorption, the bulk density of the activated carbon used was 0.3 g / cc, and the amount of activated carbon used was 0.5 g. Therefore, the calculation was based on how many cc of hydrogen was contained in 1.7 cc. At this time, the amount of hydrogen gas in the pressure vessel 10 and in the piping was subtracted for calculation.
[0015]
[Example 2]
Hydrogen was adsorbed in the same procedure as in Example 1 except that Pt, Pd, or an alloy thereof was supported on activated carbon as a substance capable of dissociating hydrogen molecules into atoms.
The supported amount was 3 wt% (in the case of an alloy, converted to Pt amount or Pd amount).
As a result, the liquefaction temperature increased to 30K.
[0016]
In addition, the hydrogen adsorption amount increased to 850.
The reason why the liquefaction temperature has increased and the amount of hydrogen adsorption has increased is not clear at present. However, since the hydrogen molecules become atomic, there is no need for ortho / para conversion, and it exists as atomic hydrogen. Therefore, it is assumed that the density is higher than that of molecular hydrogen.
[0017]
In the case of this example as well, since all of the hydrogen molecules do not dissociate into atomic hydrogen and exist as hydrogen molecules, a magnetic material such as iron oxide or chromium oxide is added to the activated carbon as in Example 1. When supported or brought into contact and promoted conversion to para-hydrogen, liquefaction was further stabilized.
[0018]
【The invention's effect】
As described above, according to the present invention, there is provided a hydrogen gas storage method capable of lowering the storage pressure and increasing the storage temperature as compared with the conventional storage method.
[Brief description of the drawings]
FIG. 1 is a cross-sectional view showing an apparatus for liquefying hydrogen gas according to the present invention.
[Explanation of symbols]
DESCRIPTION OF SYMBOLS 10 ... Glass pressure vessel 12 ... Granular adsorption material 14 ... Resin cover 15 ... Air layer 16 ... Refrigerant container 18 ... Refrigerant 20 ... Thermocouple 22 ... Pressure gauge

Claims (6)

A hydrogen gas storage method , wherein hydrogen gas is cooled and stored in a liquefied state in the presence of an adsorbent selected from activated carbon, FSM, zeolite, and metal complex .   The method according to claim 1, wherein a metal or a compound capable of dissociating hydrogen gas molecules in an atomic form is supported on or brought into contact with the adsorbent.   The method according to claim 1, wherein a catalyst for converting hydrogen gas molecules from ortho hydrogen to para hydrogen is supported on or brought into contact with the adsorbent. A pressure vessel that contains an adsorbent selected from activated carbon, FSM, zeolite, and metal complex , and stores hydrogen gas in a liquefied state ;
A cover provided outside the pressure vessel via an air layer,
A refrigerant container covering the cover via a space;
Filled up Symbol space, the refrigerant having a boiling point lower than hydrogen,
Extending from the upper Symbol pressure vessel to the outside, the hydrogen of the gaseous piping exhaust gas discharged to the outside from the pressure vessel, and
A supply pipe for supplying gaseous hydrogen from the outside to the pressure vessel ;
A hydrogen gas storage device comprising:   The apparatus according to claim 4, wherein a metal or a compound capable of dissociating hydrogen gas molecules in an atomic form is supported or brought into contact with the adsorbent.   The apparatus according to claim 4, wherein a catalyst for converting hydrogen gas molecules from ortho hydrogen to para hydrogen is supported on or brought into contact with the adsorbent.

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