Process and system for separation and recovery of perfluorocompound gases

• US 5,785,741 A
• Filed: 06/14/1996
• Issued: 07/28/1998
• 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: Paganessi, Joseph E., Li, Yao-En, Vassallo, David, Fleming, Gregory K.
• Primary Examiner(s): SPITZER, ROBERT H
• Application Number:
  US08/665,142
• Time in Patent Office: 774 Days
• Field of Search: 95/45, 95/47-49, 95/51-54, 95/90, 95/92, 95/149, 95/230, 95/237, 96/4, 96/7-14, 96/108, 96/134, 96/361
• US Class Current: 96/4
• 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 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 semiconductor manufacturing system comprising:

a) at least one reactor chamber adapted to receive perfluorocompound gases and carrier gases, the reactor chamber having a reactor effluent gas conduit attached thereto;

b) at least one glassy polymer membrane separation unit having a feed side and a permeate side, said membrane being permeable to at least one carrier gas and being substantially non-permeable to at least one perfluorocompound gas, said membrane unit connected to said reactor chamber via the reactor effluent conduit, said membrane unit having a permeate vent conduit and a non-permeate conduit; and

c) means to recycle at least a portion of a non-permeate stream from said membrane unit through said non-permeate conduit back to the at least one reactor chamber.

2. System in accordance with claim 1 including a treatment means positioned in the reactor effluent gas conduit said treatment means selected from the group consisting of plasma decomposition, thermal decomposition, catalytic removal, scrubbing, and adsorption.

3. System in accordance with claim 1 wherein the membrane unit comprises a sweep gas conduit.

4. System in accordance with claim 1 including a damper or surge tank positioned in the non-permeate conduit.

5. System in accordance with claim 1 including the provision of a compressor, heat exchanger, cryogenic pump or vacuum pump in the non-permeate conduit, allowing the non-permeate stream to be stored in condensed form for future use.

6. System in accordance with claim 1 further including post-treatment means positioned in the non-permeate conduit, said post-treatment means selected from the group consisting of plasma decomposition, thermal decomposition, catalytic removal, scrubbing, and adsorption.

7. A semiconductor manufacturing system comprising:

a) at least one reactor chamber adapted to receive perfluorocompound gases and carrier gases, the reactor chamber having a reactor effluent gas conduit attached thereto;

b) compression means located in the reactor effluent conduit to compress an effluent gas from the reactor chamber;

c) at least one glassy polymer membrane separation unit having a feed side and a permeate side, said membrane being permeable to at least one carrier gas and being substantially non-permeable to at least one perfluorocompound gas, said membrane unit connected to said reactor chamber via the reactor effluent conduit downstream of the compression means, said membrane unit having a permeate vent conduit and a non-permeate conduit;

d) means to recycle at least a portion of a non-permeate stream from said membrane unit back to the at least one reactor chamber;

e) pretreatment means positioned in the reactor effluent gas conduit said pretreatment means selected from the group consisting of plasma decomposition, thermal decomposition, catalytic removal, scrubbing, and adsorption;

f) the membrane unit comprising a sweep gas conduit connecting the non-permeate conduit and the permeate side of the membrane;

g) a damper or surge tank positioned in the non-permeate conduit; and

h) a compressor, heat exchanger, cryogenic pump or vacuum pump positioned in the non-permeate conduit upstream of the surge tank, allowing a perfluorocarbon enriched stream to be stored in liquid form for future use if so desired.