Patent ID: 6032484
Filing Date: 2000-03-07
Classification: B01D,Y02C

Abstract:
A process for the separation and recovery of fluorochemicals from a gas stream containing a diluent gas and fluorochemicals by contact of the gas stream with a membrane, comprising the steps of:(a) compressing a gas stream comprising a diluent gas and fluorochemicals to an elevated pressure;(b) heating the gas stream containing a diluent gas and fluorochemicals to an elevated temperature sufficient to increase the flux of the permeate stream of step (c) and to increase the selectivity of the membrane of step (c) for the permeation of the diluent gas of step (c) relative to the permeation of the fluorochemicals of step (c);(c) contacting the gas stream with a membrane system containing one or more stages to produce a permeate stream rich in the diluent gas and a retentate rich in fluorochemicals;(d) purifying the retentate by a process selected from the group consisting of distillation and adsorption to produce a product stream richer in fluorochemical and a recycle stream rich in diluent gas(e) recycling the permeate stream and the recycle stream for use as the diluent gas which is combined with the gas stream containing diluent gas and fluorochemicals, the combined stream, after scrubbing, being the stream supplied to step (a) to be compressed to an elevated pressure.