Process and system for separation and recovery of perfluorocompound gases

• US 6,444,011 B2
• Filed: 01/25/2001
• Issued: 09/03/2002
• Est. Priority Date: 07/17/1995
• Status: Expired due to Fees

• Current Assignee: American Air Liquide Incorporated (L'Air Liquide SA)
• Original Assignee: American Air Liquide Incorporated (L'Air Liquide SA)
• Inventors: Paganessi, Jospeh E., Li, Yao-En, Vassallo, David, Fleming, Gregory K.
• Primary Examiner(s): Spitzer, Robert H.
• Application Number:
  US09/768,262
• Publication Number:
  US 20010029841A1
• Time in Patent Office: 586 Days
• Field of Search: 95/45, 95/47--49, 95/51--54, 95/90, 95/92, 951/49, 952/30, 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 53/229 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 once 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 and recovery of at least one perfluorocompound gas from a gas mixture containing at least one carrier gas and at least one perfluorocompound gas, said process comprising the steps of:

(a) compressing a gas mixture contaning at least one carrier gas and at least one perfluorocompound gas;

(b) heating said gas mixture to a temperature sufficient to selectively increase permeation of said at least one carrier gas;

(c) contacting said gas mixture with one or more cascade connected membrane units which permeate said at least one carrier gas faster than said at least one perfluorocompound gas to obtain a permeate stream rich in said at least one carrier gas and a non-permeate stream rich in said at least one perfluorocompound gas;

(d) passing said non-permeate steam to an adsorption system to produce an adsorbed stream comprising one or more adsorbed species and a non-adsorbed stream comprising one or more non-adsorbed species; and

(e) recovering said adsorbed stream.

2. The process according to claim 1, further comprising recycling said permeate stream to step (a).

3. The process according to claim 1, which further comprises scrubbing said gas mixture to remove species harmful for the membrane units.

4. A process for the separation and recovery of at least one perfluorocompund gas from a gas mixture containing at least one carrier gas and at least one perfluorocompund gas, said process comprising the steps of:

(a) compressing a gas mixture containing at least one carrier gas and at least one perfluorocompund gas;

(b) heating said gas mixture to a temperature sufficient to selectively increase permeation of said at least one carrier gas;

(c) contacting said gas mixture with one or more cascadde connected membrane units which permeate said at least one carrier gas faster than said at least one perfluorocompound gas to obtain a permeate stream rich in said at least one carrier gas and a non-permeate stream rich in said at least one perfluorocompound gas;

(d) passing said non-permeate stream to a condensation system to produce a liquid stream rich in said at least one perfluorocompound gas and a vapor stream rich in said at least one carrier gas; and

(e) recycling at least a portion of at least one of said permeate stream and said vapor stream.

5. The process according to claim 4, which further comprises scrubbing said gas mixture to remove species harmful for the membrane units.

6. A process for the separation and recovery of at least one perfluorocompound gas from a gas mixture containing at least one carrier gas and perfluorocompound gases, said process comprising the steps of:

(a) compressing a gas mixture containing at least one carrier gas and two or more perfluorocompound gases;

(b) heating said gas mixture to a temperature sufficient to selectively increase permeation of said at least one carrier gas;

(c) contacting said gas mixture with one or more cascade connected membrane units which permeate said at least one carrier gas faster than said perfluorocompound gases to obtain a permeate stream rich in said at least one carrier gas and a non-permeate stream rich in said perfluorocompound gases;

(d) separating said two or more perfluorocompound gases in the non-permeate stream from each other by distillation; and

(e) recycling at least a portion of said permeate stream to step (a).

7. The process according to claim 6, which further comprises scrubbing said gas mixture to remove species harmful for the membrane units.