Patent ID: 7329306

Claim:
A process for the shut-down of a membrane separation zone for the removal of a readily permeable component from a feed gas mixture comprising said readily permeable component, a non-permeable component, and a less-readily permeable, condensible component, said process comprising: a) passing said feed gas mixture at separation conditions to said membrane zone having a non-permeate side and a permeate side to provide a non-permeate stream withdrawn from the non-permeate side and a permeate stream withdrawn from the permeate side at a permeate pressure; b) forming a purge stream by passing a portion of said non-permeate stream through a Joules-Thompson valve to lower the pressure and cool said portion of said non-permeate stream and then passing said portion of said non-permeate stream through a gas-liquid separator to remove said less-readily permeable, condensible component; and c) intermittently passing said purge stream at a pressure greater than the permeate pressure reduced in said less-readily permeable, condensible component relative to said non-permeate side of said membrane separation zone when said feed gas mixture is not passed to the membrane separation zone to remove at least a portion of a residual gas remaining in the non-permeate side before said residual gas condenses in said membrane separation zone.