Process and system for separation and recovery of perfluorocompound gases

• US 6,312,502 B1
• Filed: 04/23/1999
• Issued: 11/06/2001
• Est. Priority Date: 07/17/1995
• Status: Expired due to Fees

• Current Assignee: American Air Liquide Incorporated (L'Air Liquide SA), L'Air Liquide Societe Anonyme Pour L'Etude et L'Exploitation Des Procedes Georges Claude (L'Air Liquide SA)
• Original Assignee: American Air Liquide Incorporated (L'Air Liquide SA), L'Air Liquide Societe Anonyme Pour L'Etude et L'Exploitation Des Procedes Georges Claude (L'Air Liquide SA)
• Inventors: Li, Yao-En, Vassallo, David, Fleming, Gregory K., Paganessi, Jospeh E.
• Primary Examiner(s): Spitzer, Robert H.
• Application Number:
  US09/296,651
• Time in Patent Office: 928 Days
• Field of Search: 95/45, 95/47--49, 95/51--54, 95/90, 95/92, 951/49, 952/80, 952/37, 96/4, 96/7--14, 961/08, 961/34, 963/61
• US Class Current: 95/45
• CPC Class Codes: B01D 2257/204 Inorganic halogen compounds
• CPC Class Codes: B01D 2257/2066 Fluorine
• CPC Class Codes: B01D 53/22 by diffusion manufacturing semi-permeable membranes B01D67/00; form, structure or properties of semi-permeable membranes B01D69/00; material for semi-permeable membranes B01D71/00
• CPC Class Codes: B01D 53/225 Multiple stage diffusion
• CPC Class Codes: B01D 53/226 in serial connexion
• CPC Class Codes: B01D 53/228 characterised by specific membranes
• CPC Class Codes: B01D 53/229 Integrated processes (Diffusion and at least one other process, e.g. adsorption, absorption)
• CPC Class Codes: C07C 17/38 Separation; Purification; Stabilisation; Use of additives
• CPC Class Codes: C07C 19/08 containing fluorine
• CPC Class Codes: Y02C 20/30 of perfluorocarbons [PFC], hydrofluorocarbons [HFC] or sulfur hexafluoride [SF6]
• CPC Class Codes: Y02P 20/151 Reduction of greenhouse gas [GHG] emissions, e.g. CO2
• CPC Class Codes: Y02P 20/155 Perfluorocarbons [PFC]; Hydrofluorocarbons [HFC]; Hydrochlorofluorocarbons [HCFC]; Chlorofluorocarbons [CFC]

Abstract

Processes and systems to recover at least one perfluorocompound gas from a gas mixture are provided. In one embodiment the inventive process comprises the steps of a) providing a gas mixture comprising at least one perfluorocompound gas and at least one carrier gas, the gas mixture being at a predetermined pressure; b) providing at least one glassy polymer membrane having a feed side and a permeate side; c) contacting the feed side of the at least one membrane with the gas mixture; d) withdrawing from the feed side of the membrane as a non-permeate stream at a pressure which is substantially equal to the predetermined pressure a concentrated gas mixture comprising essentially the at least one perfluorocompound gas; and e) withdrawing from the permeate side of the membrane as a permeate stream a depleted gas mixture comprising essentially the at least one carrier gas.

Claims

1. A process for the separation of perfluorocompound gases from a gas mixture, said process comprising the step of:

contacting a gas mixture comprising at least one carrier gas and at least one perfluorocompound gas selected from the group consisting of CF₄, C₂F₆, C₃F₈, C₄F₁₀, and NF₃ with a membrane which permeates said at least one carrier gas faster than said at least one perfluorocompound gas.

2. The process according to claim 1, wherein said at least one carrier gas is air, nitrogen, oxygen, argon, helium, or mixtures thereof.

3. The process according to claim 1, wherein said membrane is a glassy polymeric membrane.

4. The process according to claim 1, wherein said at least one perfluorocompound gas is CF₄.

5. The process according to claim 1, wherein said at least one perfluorocompound gas is C₂F₆.

6. The process according to claim 1, wherein said at least one perfluorocompound gas is C₃F₈.

7. The process according to claim 1, wherein said at least one perfluorocompound gas is C₄F₁₀.

8. The process according to claim 1, wherein said at least one perfluorocompound gas is NF₃.