Gas stream purification

• US 4,554,141 A
• Filed: 05/14/1984
• Issued: 11/19/1985
• Est. Priority Date: 05/14/1984
• Status: Expired due to Term

• Current Assignee: SunEdison, Inc.
• Original Assignee: Ethyl Corporation (Newmarket Corporation)
• Inventors: Scull, Herbert M., Laurent, Sebastian M.
• Primary Examiner(s): Shaver, Paul F.
• Application Number:
  US06/609,812
• Time in Patent Office: 554 Days
• Field of Search: 423/245 R, 423/347
• US Class Current: 95/144
• CPC Class Codes: C01B 33/046 Purification
• CPC Class Codes: Y10S 95/902 Molecular sieve

Abstract

A process for the removal of ethylene from silane. Hydrocarbon-contaminated silane is preferably first distilled in a conventional distillation column to remove hydrocarbons boiling higher and lower than silane. Ethylene is removed by passing the silane stream through a column of zeolite, preferably zeolite A having a 4 Angstrom micropore. The 4 Angstrom zeolite A has a high capacity for ethylene and is readily regenerated.

Claims

1. A process for the purification of silane, said process comprising contacting silane contaminated with ethylene with a zeolite which has a pore structure that selectively removes ethylene and recovering the purified silane.

2. The process of claim 1 wherein said silane contains about 1-10 ppm ethylene and the silane is contacted with a zeolite so as to lower the ethylene to less than 25 ppb.

3. The process of claim 1 comprising passing silane contaminated with ethylene through a zeolite A having a micropore of about 4 Angstroms and recovering the purified silane.

4. The process of claim 3 wherein said zeolite A is of the sodium cation form.

5. The process of claim 3 wherein about one part or less by weight zeolite A is used per 40 parts by weight silane.

6. The process of claim 3 wherein said silane contains at least about 25 parts by weight ethylene per billion parts by weight silane.

7. The process of claim 3 wherein said silane contaminated with ethylene also contains another hydrocarbon.

8. The process of claim 7 wherein said hydrocarbon is methane or ethane.

9. The process of claim 3 wherein said process is carried out in a column of said zeolite A.

10. The process of claim 3 wherein said zeolite A is in the form of small diameter extrudate.

11. The process of claim 3 wherein the ethylene contaminant is present in the silane at the level of up to about 10 ppm by weight.

12. The process of claim 1 wherein the process is carried out at a temperature below about 30°

C.

13. A process for the removal of hydrocarbon contaminants from silane said process comprising the steps of:

(a) distilling silane contaminated with hydrocarbon contaminants including ethylene so as to remove hydrocarbons other than ethylene;

(b) passing the distilled silane through a zeolite having a pore structure that selectively removes ethylene; and

(c) recovering the purified silane.

14. The process of claim 13 wherein said hydrocarbon contaminants include methane or ethane.

15. The process of claim 13 wherein said zeolite is a zeolite A having a micropore structure of about 4 Angstroms.

16. The process of claim 15 wherein said zeolite A is a sodium cation zeolite A.

17. The process of claim 15 wherein at least one part by weight zeolite A is used per 40 parts by weight distilled silane.

18. The process of claim 15 wherein said zeolite A is in the form of small diameter extrudate.

19. The process of claim 13 wherein said process is carried out at a temperature below about 30°

C.