JP3304383B2 - Hydrogen mixed gas adsorbent - Google Patents

Description

[Detailed description of the invention]

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention This invention relates to an adsorbent for hydrogen gas mixtures . In more detail, we recommend hydrogen-mixed
It relates to adsorbents for combined gas .

[0002]

2. Description of the Related Art At present, fossil fuels such as petroleum are mainly used as energy sources, but in recent years, problems such as air pollution, acid rain, and global warming associated with the combustion of these fuels have arisen. In order to solve such environmental problems, it is necessary to hasten the development of clean energy, and hydrogen gas is attracting attention as one of them.

Methods for producing hydrogen gas include steam reforming of natural gas, steam reforming of methanol, and coal gasification. It is a mixed gas such as nitrogen, and it needs to be separated to obtain pure hydrogen gas.

[0004] Methods for separating hydrogen gas from such a hydrogen mixed gas include cryogenic separation, absorption, adsorption separation, membrane separation and the like.
A separation method using PSA (Presure Swing Adsorption) is attracting attention. In this PSA separation method, Molecular Sieve 5A (product of UCC) is used as an adsorbent for hydrogen gas separation.

[0005] Separating hydrogen gas from a hydrogen mixed gas also means that carbon dioxide gas and nitrogen gas should be adsorbed and removed from the hydrogen mixed gas. The law also follows this line of thinking. Therefore, in order to increase the separation efficiency by PSA, it is necessary to improve the selective adsorption of the adsorbent.

[0006]

SUMMARY OF THE INVENTION An object of the present invention is to provide a hydrogen mixed gas which can be an adsorbent with improved selective adsorption when applied to a mixed gas such as hydrogen, carbon dioxide and nitrogen.
An object of the present invention is to provide a gas adsorbent .

[0007]

DISCLOSURE OF THE INVENTION The object of the present invention is to:
Hydrogen mixed gas comprising Ca-containing synthetic zeolite A obtained by Ca ion exchange reaction of transition metal-containing synthetic zeolite A
This is achieved by a gas adsorbent .

Transition metal-containing synthetic zeolite A is produced by reacting an aqueous solution of sodium aluminate and an aqueous solution of sodium silicate to produce synthetic zeolite A, in which an aqueous inorganic salt solution of a transition metal is added to the zeolite A synthetic mother liquor to cause the reaction. obtained by

The reaction of an aqueous sodium aluminate solution with an aqueous sodium silicate solution (including an aqueous solution of water glass) is carried out according to a conventional reaction method. An aqueous solution of sulfate or the like is added into the synthesis mother liquor of Zeolite A and allowed to react.

The transition metal is used in a molar ratio of about 0.1-0.4 to Al ₂ O ₃ derived from sodium aluminate in terms of oxide. If the molar ratio is less than this, the supported amount of the transition metal is too small.
Also, relative to _{Al2O3 , SiO2} is about 1.8-2.2, preferably about 1.8-2.0, _H2O is about 200-300, preferably about 220-250.
used in a molar ratio of

The reaction is carried out by instantaneously adding an aqueous sodium silicate solution to an aqueous sodium aluminate solution under strong stirring conditions,
An aqueous inorganic salt solution of a transition metal is further added to this zeolite A synthetic mother liquor, and the synthetic mother liquor obtained in this way is
Stir for 60 minutes, then place in a pressure-resistant container and heat at room temperature to about 120°C.
for about 5 to 60 hours, preferably about 100 to 120°C for about 5 to 40 hours.

In the conventional method, transition metal-supported synthetic zeolite A is obtained through three steps of synthesis of zeolite A, preparation of an aqueous ammine complex solution, and ion exchange or impregnation support. Synthetic zeolite A can be obtained.

The transition metal-containing synthetic zeolite A thus obtained is immersed in an aqueous calcium salt solution having a concentration of about 0.1 to 1 mol, such as an aqueous solution of calcium chloride, calcium nitrate, etc., to cause a Ca ion exchange reaction. .
The immersion is carried out at room temperature for about 48 to 60 hours, and when heated, the temperature is below the reflux temperature of the aqueous solution used.

Calcium-containing synthetic zeolite A obtained
is effectively used as an adsorbent in separating hydrogen gas from its mixture. Adsorption can be done in a variety of ways, but is preferably done by the PSA separation method. Apparatuses used in this separation method include single-column, double-column and other multi-column devices.

[0015]

Effects of the Invention When separating hydrogen gas from a hydrogen mixed gas, a transition metal-containing synthetic zeolite A is used as a gas adsorbent.
When using the calcium-containing synthetic zeolite A obtained by Ca ion exchange reaction , the CO ₂ adsorption amount is slightly lower than when molecular sieve 5A, which is conventionally used in the PSA separation method, is used, but the N ₂ adsorption amount is is large, and the adsorption amount ratio ( _CO2 adsorption amount + _N2 adsorption amount) / ₍ H2 adsorption amount) is taken as an index when removing _CO2 and _N2 from H2 _{- CO2} - _N2 mixed gas. When compared, the effect of excellent adsorption selectivity can be obtained.

[0016]

EXAMPLES The present invention will now be described with reference to examples.

Example Sodium aluminate Na ₂ O.Al ₂ O ₃ Water glass Na ₂ O.n SiO ₂ Nickel nitrate Ni(NO ₃ ) _{2.6H 2} O _{2O3 _}
- 1.82 _SiO2 - 0.101 NiO - 235 _H2O , and instantaneously mixed and stirred in this order. This synthetic mother liquor was placed in a pressure vessel and heated at 120° C. for 10 hours to obtain a Ni-containing synthetic zeolite A.

20 g of the resulting Ni-containing synthetic zeolite A was
48 at room temperature in 200 ml of molarity calcium chloride aqueous solution.
It was immersed for a period of time, and a Ca ion exchange reaction (exchange rate of about 30%) was performed.

This Ca-containing synthetic zeolite A was heated at 673K for 5
After heat treatment for 1 hour, further heat treatment at 473 K under a reduced pressure of about 1.5 kPa for 1
Time drying, the adsorption amount for pure H2 gas, pure _N2 gas or pure _CO2 gas was individually measured under the conditions of adsorption temperature _298K , adsorption pressure 208kPa, adsorption time 30min. Then, the adsorption amount was calculated from the pressure fluctuation observed by the pressure sensor incorporated in the adsorption amount measuring device.

Comparative Example 1 Regarding the Ni-containing synthetic zeolite A used in the examples,
Measurements similar to those in the examples were performed.

Comparative Example 2 Using molecular sieve 5A (CaA type) , the same measurement as in Example was performed.

Comparative Example 3 20 g of molecular sieve 5A was immersed in 200 ml of a 1 mol concentration Ni hexaammine complex aqueous solution at room temperature for 48 hours to ion-exchange Ni with Na and Ca in the molecule (ion exchange rate of about 19%). Using this, the same measurements as in the example were performed.

The measurement results in the above examples and comparative examples are shown in the following table. Table adsorption amount [/cm ³ (stp)/cm ³ adsorbent] adsorption amount proportional H ₂ N ₂ CO ₂ [q(CO ₂ ) + q(N ₂ )]/q(H ₂ ) Example 0.852 3.775 12.886 19.555 Comparative Example 1 0.985 3.412 13.220 16.885 〃 2 0.851 2.953 13.115 18.881 〃 3 0.934 3.057 13.218 17.425

──────────────────────────────────────────────────── ─── Continuation of the front page (58) Researched field (Int.Cl. ⁷ , DB name) C01B 33/00 - 39/54 B01D 53/02 B01D 53/04 B01J 20/18 CA (STN) JICST file ( JOIS)

Claims (1)

(57) [Claims] [Claim 1] From Ca-containing synthetic zeolite A obtained by Ca ion exchange reaction of transition metal-containing synthetic zeolite A
Adsorbent for hydrogen mixed gas .