Adsorbents, method for the preparation and method for the separation of unsaturated hydrocarbons for gas mixtures

• US 6,315,816 B1
• Filed: 10/04/1999
• Issued: 11/13/2001
• Est. Priority Date: 09/23/1999
• Status: Expired due to Term

• Current Assignee: Korea Institute of Energy Research, Indian Petrochemicals Corp. Ltd. (Reliance Industries Limited)
• Original Assignee: Korea Institute of Energy Research, Indian Petrochemicals Corp. Ltd. (Reliance Industries Limited)
• Inventors: Han, Sang Sup, Cho, Soon Haeng, Kim, Jong Nam, Bhat, Sodankoor Garadi Thirumaleshwara, Kumar, Prakash, Choudary, Nettem Venkateswarlu
• Primary Examiner(s): Spitzer, Robert H.
• Application Number:
  US09/411,990
• Time in Patent Office: 771 Days
• Field of Search: 95/95, 95/96, 95/114, 95/143, 95/144, 95/900, 502/34, 502/56, 502/62, 502/83, 502/84, 585/820, 585/826, 585/829, 585/830, 96/108
• US Class Current: 95/96
• 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: B01J 20/0233 Compounds of Cu, Ag, Au
• CPC Class Codes: B01J 20/0288 Halides of compounds other than those provided for in B01J20/046
• CPC Class Codes: B01J 20/0296 Nitrates of compounds other than those provided for in B01J20/04
• CPC Class Codes: B01J 20/12 Naturally occurring clays or bleaching earth
• CPC Class Codes: B01J 20/223 containing metals, e.g. organo-metallic compounds, coordination complexes
• CPC Class Codes: B01J 20/28004 Sorbent size or size distribution, e.g. particle size
• CPC Class Codes: B01J 20/28061 being in the range 100-500 m2/g
• CPC Class Codes: B01J 20/3042 Use of binding agents; addition of materials ameliorating the mechanical properties of the produced sorbent
• CPC Class Codes: B01J 20/3085 Chemical treatments not covered by groups B01J20/3007 - B01J20/3078
• CPC Class Codes: B01J 20/3204 Inorganic carriers, supports or substrates
• CPC Class Codes: B01J 20/3236 containing metal, other than zeolites, e.g. oxides, hydroxides, sulphides or salts
• CPC Class Codes: B01J 20/3272 Polymers obtained by reactions otherwise than involving only carbon to carbon unsaturated bonds
• CPC Class Codes: B01J 20/3289 Coatings involving more than one layer of same or different nature
• CPC Class Codes: B01J 20/3433 of sorbents or filter aids other than those covered by B01J20/3408 - B01J20/3425
• CPC Class Codes: B01J 20/3483 by thermal treatment not covered by groups B01J20/3441 - B01J20/3475, e.g. by heating or cooling
• CPC Class Codes: B01J 20/3491 by pressure treatment
• CPC Class Codes: B01J 2220/42 Materials comprising a mixture of inorganic materials materials coated or impregnated on a carrier B01J20/32
• CPC Class Codes: B01J 2220/58 Use in a single column
• CPC Class Codes: Y02C 20/20 of methane
• CPC Class Codes: Y10S 95/90 : Solid sorbent

Abstract

A group of solid adsorbents in the form of powder, granules or pellets having improved adsorptive capacity and selectivity for ethylene and/or propylene is disclosed. These adsorbents comprise (a) a silver compound and (b) a bentonite clay support bulk of which comprises SiO₂ and Al₂O₃ and the rest being oxides of Fe, Ca, Mg, Na and K and having sufficiently high surface area on which the silver compound is dispersed or impregnated. The support may be pretreated by polymer solutions to impart sufficient mechanical strength as measured by attrition loss. Mechanical strength may also be improved by pre-heating the support. These adsorbents are highly stable and are capable of reversibly adsorbing substantial quantity of ethylene and/or propylene at room temperature. The rates of adsorption of ethylene and/or propylene are also very high in these adsorbents, which is believed to be due to the synergistic interaction between the components of the novel composition of the present invention.

Claims

1. A process for the separation of olefin molecules or mixtures thereof from a mixed gas containing said olefin molecules or a mixture thereof, which comprises:

passing said mixed gas through an adsorbent comprising a (i) a silver compound and (ii) an activated bentonite clay support the bulk of which is made of SiO₂ and Al₂O₃ and the balance being oxides of Fe, Ca, Mg, Na and K, at a temperature in the range of from 0 to 100°

C. and a pressure in the range of 1 to 100 atmospheres, to effect adsorption of said olefin, and releasing the adsorbed olefin.

2. A process as claimed in claim 1, wherein the mixed gas comprises a component selected from the group consisting of H₂, N₂, Ar, He, CH₄, C₂H₂, C₂H₆, C₃H₈, CO, CO₂ and mixtures thereof.

3. A process as claimed in claim 1, wherein said olefin is ethylene or propylene.

4. A process as claimed in claim 1 wherein the releasing is accompanied by lowering the pressure and/or heating the support.

5. An adsorbent composition for the selective adsorption of unsaturated hydrocarbons from a mixture thereof with one or more of saturated hydrocarbons, carbon dioxide, permanent gases or mixtures thereof, said adsorbent comprising:

a silver compound and an activated bentonite clay support the bulk of which is made of SiO₂ and Al₂O₃ and the balance being oxides of Fe, Ca, Mg, Na, and K, being present in the following proportions by weight;

6. An adsorbent as claimed in claim 5 wherein the silver compound is selected from the group consisting of silver nitrate, silver halides, silver perchlorate, silver tetrafluoroborate, silver carboxylates, and silver oxide and any mixture thereof.

7. An adsorbent as claimed in claim 6 wherein said silver halides are selected from the group comprising of silver chloride, silver bromide and silver iodide.

8. An adsorbent as claimed in claim 6 wherein said silver carboxylates are selected from silver formate and silver acetate.

9. An adsorbent as claimed in claim 5 wherein said activated bentonite clay support is an acid activated bentonite clay support.

10. An adsorbent as claimed in claim 9 wherein said acid is a mineral acid.

11. An adsorbent as claimed in claim 5 wherein said activated bentonite clay support is pretreated by polymer solutions.

12. An adsorbent as claimed in claim 5 wherein said activated bentonite clay support is preheated to improve mechanical support.

13. An adsorbent as claimed claim 5 wherein said support has a surface area of 100-400 m²/g.

14. A process for the preparation of an adsorbent for the selective adsorption of unsaturated hydrocarbons from their mixture with one of saturated hydrocarbons, carbon dioxide, permanent gases or mixtures thereof, said process comprising dispersing or impregnating a silver compound in a solid form or in a solution, with a support material comprising activated bentonite clay, and subjecting the resultant composite material to heat treatment to produce said adsorbent, wherein said activated bentonite clay has the following composition:

15. A process as claimed in claim 14 wherein said silver compound is selected from the group consisting of silver nitrate, silver halides, silver perchlorate, silver tetrafluorobrate, silver carboxylates and silver oxide and any mixture thereof.

16. A process as claimed in claim 14 wherein the said support is activated by treatment with a mineral acid.

17. A process as claimed in claim 14 wherein said activated bentonite clay has a surface area of 100-400 m²/g.

18. A process as claimed in claim 14 wherein said activated bentonite clay has a pH in the range of 2 to 7.

19. A process as claimed in claim 18, wherein the pH is in the range of 4 to 7.

20. A process as claimed in claim 14 wherein the silver compound is in the form of a solution.

21. A process as claimed in claim 20, wherein the solution comprises a solvent and the solvent is selected from the group consisting of water, alcohol, hydrocarbons, aqueous hydrochloric acid, acetone, ethyl acetate, propionitrile and acetonitrile.

22. A process as claimed in claim 21 wherein said alcohol is selected from primary or secondary alcohol having from 1 to 7 carbon atoms and said hydrocarbons are selected from hydrocarbons having from 4 to 7 carbon atoms.

23. A process as claimed in claim 14 wherein after contacting said solution of the silver compound with said support material, the reaction mixture is equilibrated for a period of 0.1 to 24 hours.

24. A process as claimed in claim 23 wherein after the reaction mixture is equilibrated excess solvent is removed by heating or purging with an inert gas.

25. A process as claimed in claim 23, wherein the reaction mixture is equilibrated for a period of 1 to 4 hours.

26. A process as claimed in claim 14 wherein the heat treatment is carried out at a temperature of 30 to 350°

C.

27. A process as claimed in claim 26 wherein the heat treatment is carried for 0.1 to 48 hours.

28. A process as claimed in claim 27 wherein said heat treatment is carried out in an atmosphere of nitrogen or helium.

29. A process as claimed in claim 28, wherein said heat treatment is carried out for 1 to 10 hours.

30. A process as claimed in claim 26, wherein said heat treatment is carried out at a temperature of 100 to 250°

C.

31. A process as claimed in claim 14 wherein said activated clay support is a polymer pretreated support or a heat pretreated support.

32. A process as claimed in claim 31 wherein said polymer is selected from the group consisting of polycarbonates, methyl cellulose and ethyl cellulose.

33. A process for the preparation of an adsorbent having improved mechanical strength for the selective adsorption of unsaturated hydrocarbons from a mixture thereof with one of saturated hydrocarbons, carbon dioxide, permanent gases or mixtures thereof, said process comprising dispersing or impregnating a silver compound in a solid form or in solution, with a support material comprising activated bentonite clay, the bulk of which is made of SiO₂ and Al₂O₃ and the balance being oxides of Fe, Ca, Mg, Na, and K and subjecting the resultant composite material to heat treatment to produce said adsorbent, wherein said support is treated with a solution of a polymer prior to or after impregnating said silver compound.

34. A process as claimed in claim 33 wherein said support is treated with a solution of a polymer obtained by dissolving said polymer in a solvent to form a polymeric solution, treating said support with said polymeric solution followed by equilibration, removing said solvent and heating said support at a temperature of 100 to 250°

C.

35. A process as claimed in claim 34 wherein said solvent is selected from the group consisting of chloroform, methyl ethyl ketone, methyl alcohol, ethyl alcohol and acetone.

36. A process as claimed in claim 35 wherein said equilibration is carried out for a period of 10 minutes to 2 hrs.

37. A process as claimed in claim 34 wherein said support is heated for 1 to 10 hrs.

38. A process as claimed in claim 33 wherein said polymer is selected from the group consisting of polycarbonates, methyl cellulose and ethyl cellulose.

39. A process for the preparation of an adsorbent having improved mechanical strength for the selective adsorption of unsaturated hydrocarbons from its mixture with one of saturated hydrocarbons, carbon dioxide, permanent gases or mixtures thereof, said process comprising providing a support material comprising activated bentonite clay, the bulk of which is made of SiO₂ and Al₂O₃ and the balance being oxides of Fe, Ca, Mg, Na and K, heating said support material to a temperature in a range of 150 to 500°

C. for a period of 0.5 to 21 hrs, dispersing or impregnating a silver compound in a solid form or in a solution, on said support which has been heated and subjecting the resultant composite material to heat treatment to produce adsorbent having improved mechanical properties.