Separation of hydrocarbons

Claim 1

IN THE PROCESS OF SEPARATING A MIXTURE OF A LEAST TWO SATURATED HYDROCARBONS BY INTRODUCING SAID MIXTURE INTO THE FEED ZONE OF A PERMEATION APPARATUS COMPRISED OF A FEED ZONE WHICH IS SEALED FROM A PERMEATE ZONE BY A THIN PLASTIC MEMBRANE IN WHICH INE OF THE HYDROCARBONS CONTAINED IN SAID MIXTURE OF SATURATED HYDROCARBONS IS MORE SOLUBLE THAN OTHERS, IN WHICH PROCESS A PORTION OF SAID MIXTURE OF SATURATED HYDROCARBONS IS PERMEATED THROUGH SAID MEMBRANE INTO THE PERMEATE ZONE AND THE PERMEATED PORTION IS WITHDRAWN FROM SAID PERMEATE ZONE AND A NON-PERMEATED PORTION IS WITHDRAWN FROM TAHE FEED ZONE, SAID PERMEATED PORTION BEING ENRICHED IN THE SATURATED HYDROCARBON WHICH IS MORE SOLUBLE IN THE MEMBRANE, THE IMPORVEMENT WHICH COMPRISES INCREASING THE RATE OF PERMEATION OF HYDROCARBONS THROUGH THE MEMBRANE BY CONTACTING THE MEMBRANE DURING PERMEATION WITH AN ADDED HYDROCARBON SOLVENT FOR SAID MEMBRANE, SAID MEMBRANE SOLVENT BEING SELECTED FROM THE GROUP CONSISTING OF AROMATIC HYDROCARBONS, UNSATURATED HYDROCARBONS, AND MIXTURES THEREOF, AND SAID HYDROCARBON SOLVENT BEING IN ADDITION TO ANY HYDROCARBONS ORIGINALLY OCCURRING IN THE FEED MIXTURE AND TO ANY RECYCLE HYDROCARBONS DERIVED FROM THE FEED MIXTURE, AND CARRYING OUT THE PERMEATION IN THE PRESENCE OF SAID HYDROCARABON SOLVENT IN AN AMOUNT OF THE LATTER SUFFICIENT TO SUBSTANTIALLY INCREASE THE RATE OF PERMEATION OF SATURAATED HYDROCARABONS THROUGH SAID PERMEATION MEMBRANE.