CO.sub.2 removal from high CO.sub.2 content hydrocarbon containing streams

Process for treating a gaseous stream comprising:

• (a) separating a first portion of predominantly higher (C.sub.3 and heavier) hydrocarbons from a gaseous stream such that hydrocarbon condensation does not occur from the resulting stream comprising CO.sub.2 and at least C.sub.1 and C.sub.2 hydrocarbons during CO.sub.2 removal during Step (b) hereinafter set forth, the gaseous stream comprising CO.sub.2 and hydrocarbons including at least C.sub.1 and C.sub.2 hydrocarbons, and further including C.sub.3 and heavier hydrocarbons such that hydrocarbon condensation occurs during removal of CO.sub.2 unless the gaseous stream is treated prior to CO.sub.2 removal to remove said first portion of the hydrocarbons;
• then
• (b) introducing said resulting stream comprising CO.sub.2 and at least C.sub.1 and C.sub.2 hydrocarbons into a permeation zone and separating a first portion of CO.sub.2 from said resulting stream in the permeation zone by selective permeation of CO.sub.2 across a differentially permeable membrane to produce a CO.sub.2 permeate stream and a hydrocarbon enriched first stream comprising C.sub.1 and C.sub.2 hydrocarbons;
• and
• (c) further separating CO.sub.2 from the hydrocarbon enriched first stream in at least one CO.sub.2 removal zone by cryogenically fractionating the hydrocarbon enriched first stream to produce at least a C.sub.1 stream and a CO.sub.2 stream.