NOVELTY - A gas stream is separated into component fractions by cooling gas feed in heat exchanger(s) to provide first 3-Carbon (propane and propylene) containing-liquid with lighter hydrocarbons, and introducing to heavy ends fractionation column. A cooled 2-Carbon containing-liquid is fed to light-ends fractionating column to liquefy higher percent of 3-Carbon and recover heavier hydrocarbons.    USE - For separating gas stream containing e.g., methane, 2C components (ethylene and ethane), 3C component (propylene and propane) and heavier hydrocarbon components into volatile and less volatile residue gases.    ADVANTAGE - The inventive process gives an increased yield of propylene and propane at reduced energy consumption.    DETAILED DESCRIPTION - Separation of gas stream into volatile residue gas fraction and less volatile fraction involves cooling the gas feed in heat exchanger(s) to provide first residue vapor and first 3C containing-liquid containing lighter hydrocarbons. A portion of first 3C containing-liquid is directed into heavy ends fractionation column to separate the liquid into second residue containing lighter hydrocarbons and 3C containing-product. The second residue is cooled to condense into 2C containing-liquid stream and fourth residue vapor. The 2C containing liquid is further cooled and contacted with the first residue vapors in a fractionation device having a contacting stage which separates the third residue vapor and resulting second 3C containing-liquid. Liquids recovered from the fractionation column are supplied into heat exchanger to supply cooling and then into the heavy ends of fractionation column as a feed. Fourth residue vapors are supplied into heat exchanger to supply a portion of cooling and to discharge residue gases.    An INDEPENDENT CLAIM is also included for an apparatus for separating a feed gas into component fractions comprising separator for receiving feed gas. A heavy ends fractionation column receives 3C containing liquids and for separating the received liquid into second residue containing lighter liquid hydrocarbons and 3C containing liquid product. A first heat exchange systems cools and condenses the second residue from heavy ends fractionation column. A second heat exchange system further cools the 2C containing liquids. A light ends fractionation column receives first residue vapors and cooled 2C containing liquids and to co-mingle the vapor and liquid in contacting stage(s).