Method for purifying hydrogen-based gas mixture

• US 6,514,317 B2
• Filed: 04/20/2001
• Issued: 02/04/2003
• Est. Priority Date: 04/20/2000
• Status: Active Grant

• Current Assignee: Tosoh Corporation
• Original Assignee: Tosoh Corporation
• Inventors: Harada, Atsushi, Hirano, Shigeru
• Primary Examiner(s): Spitzer, Robert H.
• Application Number:
  US09/838,146
• Publication Number:
  US 20010045160A1
• Time in Patent Office: 655 Days
• Field of Search: 95/96--06, 951/14, 951/15, 951/17, 951/30, 951/39, 951/40, 951/43, 959/02
• US Class Current: 95/96
• CPC Class Codes: B01D 2253/108 Zeolites
• CPC Class Codes: B01D 2253/304 Linear dimensions, e.g. particle shape, diameter
• CPC Class Codes: B01D 2253/308 Pore size
• CPC Class Codes: B01D 2253/311 Porosity, e.g. pore volume
• CPC Class Codes: B01D 2256/16 Hydrogen
• CPC Class Codes: B01D 2257/102 Nitrogen
• CPC Class Codes: B01D 2257/502 Carbon monoxide
• CPC Class Codes: B01D 2257/7022 Aliphatic hydrocarbons
• CPC Class Codes: B01D 53/02 by adsorption, e.g. preparative gas chromatography solid sorbent compositions B01J20/00, preparation of inorganic compounds or elements C01
• CPC Class Codes: B01D 53/04 with stationary adsorbents B01D53/025 takes precedence
• CPC Class Codes: B01D 53/0462 Temperature swing adsorption
• CPC Class Codes: B01D 53/047 Pressure swing adsorption
• CPC Class Codes: B01J 20/183 Physical conditioning without chemical treatment, e.g. drying, granulating, coating, irradiation
• CPC Class Codes: B01J 20/186 Chemical treatments in view of modifying the properties of the sieve, e.g. increasing the stability or the activity, also decreasing the activity
• CPC Class Codes: C01B 2203/043 Regenerative adsorption process in two or more beds, one for adsorption, the other for regeneration
• CPC Class Codes: C01B 2203/0465 Composition of the impurity
• CPC Class Codes: C01B 2203/047 the impurity being carbon monoxide
• CPC Class Codes: C01B 2203/0475 the impurity being carbon dioxide
• CPC Class Codes: C01B 2203/048 the impurity being an organic compound
• CPC Class Codes: C01B 2203/0495 the impurity being water
• CPC Class Codes: C01B 3/56 : by contacting with solids; Regeneration of used solids C01B3/508 takes precedence
• CPC Class Codes: Y10S 95/902 : Molecular sieve

Abstract

Purification of a hydrogen-based gas mixture containing impurities such as carbon monoxide, nitrogen and methane is effected by contacting the gaseous mixture with a zeolite adsorbent which is a shaped product comprised of at least 95%, as determined on the basis of the moisture equilibrium adsorption value, of a low-silica type X zeolite having a SiO₂/Al₂O₃ molar ratio of 1.9 to 2.1. The zeolite adsorbent is preferably ion-exchanged with lithium and/or calcium. The zeolite adsorbent is preferably prepared by a process including a step of contacting with a caustic solution a calcined product of a mixture of a low-silica type X zeolite and kaolin clay whereby the kaolin clay is converted to a low-silica type X zeolite.

Claims

1. A method for purifying a hydrogen-based gas mixture comprising the step of contacting said hydrogen-based gas mixture with a zeolite adsorbent;

said zeolite adsorbent being a shaped product which is comprised of at least 95%, as determined on the basis of the moisture equilibrium adsorption value, of a low-silica type X zeolite having a SiO₂/Al₂O₃ molar ratio in the range of 1.9 to 2.1, and has an average crush strength of at least 1.0 kgf as measured on particles of said shaped product having a particle diameter in the range of 1.4 to 1.7 mm prepared for crush strength measurement.

2. The method according to claim 1, wherein said shaped product of said low-silica type X zeolite contains at least one kind of cation selected from the group consisting of lithium, sodium, potassium, magnesium, calcium and zinc.

3. The method according to claim 1, wherein said shaped product of said low-silica type X zeolite has been ion-exchanged with a lithium ion at an ion exchange ratio of at least 90%.

4. The method according to claim 1, wherein said shaped product of said low-silica type X zeolite has been ion-exchanged with a lithium ion at an ion exchange ratio of at least 95%.

5. The method according to claim 1, wherein said shaped product of said low-silica type X zeolite has been ion-exchanged with a calcium ion at an ion exchange ratio of at least 50%.

6. The method according to claim 1, wherein said shaped product of said low-silica type X zeolite has been ion-exchanged with a calcium ion at an ion exchange ratio of at least 80%.

7. The method according to claim 1, wherein said shaped product of said low-silica type X zeolite has been ion-exchanged with a calcium ion at an ion exchange ratio of at least 90%.

8. The method according to claim 1, wherein said shaped product is comprised of at least 98% by weight, as determined on the basis of the moisture equilibrium adsorption value, of said low-silica type X zeolite.

9. The method according to claim 1, wherein said shaped product is substantially free from a binder.

10. The method according to claim 1, wherein said shaped product of said low-silica type X zeolite has a macro pore volume of at least 0.25 ml/g and an average pore diameter of at least 0.35 μ

m.

11. The method according to claim 1, wherein said shaped product of said low-silica type X zeolite is a particle having an average particle diameter in the range of 0.5 to 3 mm.

12. The method according to claim 1, wherein said shaped product of said low-silica type X zeolite is a particle having an average particle diameter in the range of 0.5 to 2 mm.

13. The method according to claim 1, wherein said hydrogen-based gas mixture comprises, in addition to hydrogen, at least one gas selected from the group consisting of carbon dioxide, carbon monoxide, nitrogen, water vapor and hydrocarbons.

14. The method according to claim 1, wherein said hydrogen-based gas mixture comprises, in addition to hydrogen, at least one gas selected from the group consisting of carbon monoxide, nitrogen and methane.

15. The method according to claim 1, wherein said gas mixture is contacted with the zeolite adsorbent by at least one method selected from a pressure swing adsorption method and a temperature swing adsorption method.

16. The method according to claim 15, wherein said hydrogen-based gas mixture is contacted with said zeolite adsorbent at an adsorption pressure of 3 to 30 atm.

17. The method according to claim 1, wherein the shaped product has been prepared by a process comprising:

shaping a mixture comprising a low-silica type X zeolite having a SiO₂/Al₂O₃ molar ratio in the range of 1.9 to 2.1 and a kaolin clay having a SiO₂/Al₂O₃ molar ratio in the range of 1.9 to 2.1,

calcining the thus-shaped product, and then

contacting the calcined shaped product with a caustic solution capable of dissolving silicon from said calcined shaped product in an amount larger than that of aluminum dissolved from said calcined shaped product whereby the kaolin clay contained in said calcined shaped product is converted to said low-silica type X zeolite.

18. The method according to claim 17, wherein said calcined shaped product is kept in contact with a caustic solution of at least 6 moles per liter, for at least 10 hours.

19. The method according to claim 17, wherein said calcined shaped product is kept in contact with a caustic solution of at least 8 moles per liter, for at least 5 hours.

20. The method according to claim 17, wherein said caustic solution contains an aluminum ingredient previously incorporated therein.

21. The method according to claim 1, wherein said shaped product consists essentially of said low-silica type X zeolite.

22. A method for purifying a hydrogen-based gas mixture comprising the step of contacting said hydrogen-based gas mixture with a zeolite adsorbent;

said zeolite adsorbent being a shaped product comprised of at least 95%, as determined on the basis of the moisture equilibrium adsorption value, of a low-silica type X zeolite having a SiO₂/Al₂O₃ molar ratio in the range of 1.9 to 2.1, said shaped product having an average crush strength of at least 1.0 kgf as measured on particles of the shaped product having a particle diameter in the range of 1.4 to 1.7 mm prepared for crush strength measurement;

said shaped product of the low-silica type X zeolite having been ion-exchanged with a lithium ion at an ion exchange ratio of at least 90%.

23. The method according to claim 22, wherein said shaped product consists essentially of said low-silica type X zeolite.

24. The method according to claim 22, wherein said shaped product is substantially free of binder.