Refrigeration – Cryogenic treatment of gas or gas mixture – Separation of gas mixture
Patent
1998-03-23
2000-03-07
Doerrler, William
Refrigeration
Cryogenic treatment of gas or gas mixture
Separation of gas mixture
95 48, F25J 300, B01D 5322
Patent
active
060324848
ABSTRACT:
A method for the separation and recovery of fluorochemicals from a gas stream containing a diluent gas and fluorochemicals by first contacting the gas stream with a membrane system in one or more stages where the membrane(s) is selectively more permeable to the diluent gas than the fluorochemicals to result in a permeate stream rich in diluent gas and retentate rich in fluorochemicals, thereafter subjecting retentate the gas stream to a purification by distillation or adsorption resulting in a product stream enriched in fluorochemicals and a purified diluent stream. The purified diluent stream is used as a purge stream and/or a recycle stream together with the permeate stream to a vacuum pump upstream of the membrane separation step.
A product stream can be produced from a similar gas stream containing diluent gas and fluorochemical by an adsorption step combined with a subsequent distillation step where the purified diluent from the adsorption step is used as a purge stream and/or wholly or partial combined with a purified diluent stream from the distillation step as a recycle stream introduced into the process upstream of the adsorption step.
Enriched fluorochemical and an enriched diluent streams can be produced from a stream containing diluent gas and fluorochemicals by cryogenic distillation with the enriched diluent stream recycled to the process upstream of the distillation step.
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Chernyakov Iosif
Hsiung Thomas Hsiao-Ling
Schwarz Alexander
Yang James Hsu-Kuang
Air Products and Chemicals Inc.
Chase Geoffrey L.
Doerrler William
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