Patent ID: 6053965
Filing Date: 2000-04-25
Classification: B01D

Abstract:
A process for conditioning a portion of a high-pressure gas stream, the gas stream comprising methane and C.sub.3+ hydrocarbons, and the process comprising the following steps:(a) withdrawing the portion from the high-pressure gas stream;(b) passing the portion through a heat-exchange step in heat-exchanging relationship against a membrane residue stream, thereby cooling the portion;(c) separating the portion into a liquid phase comprising C.sub.3+ hydrocarbons and a gas phase depleted in C.sub.3+ hydrocarbons;(d) providing a membrane unit having a feed side and a permeate side and containing a membrane selective for C.sub.3+ hydrocarbons over methane;(e) passing the gas phase across the feed side under conditions in which transmembrane permeation occurs;(f) withdrawing from the feed side the membrane residue stream;(g) withdrawing from the permeate side a membrane permeate stream enriched in C.sub.3+ hydrocarbons compared with the gas phase;(h) passing the membrane residue stream to the heat-exchange step (b);(i) withdrawing the membrane residue stream from the heat-exchange step; the process being characterized in that the liquid phase has a C.sub.3+ hydrocarbons flow of L lb/h, the membrane permeate stream has a second C.sub.3+ hydrocarbons flow of P lb/h and the distribution of C.sub.3+ hydrocarbons between the liquid phase and the membrane permeate stream is such that L/(L+P).times.100% is a percentage between about 30% and 80%.