Patent ID: 6109061
Filing Date: 2000-08-29
Classification: F25J

Abstract:
A process for separation of a relatively hot, methane rich feed gas containing methane, ethane and heavier hydrocarbon constituents into a volatile residue gas containing primarily methane and ethane and a relatively less volatile fraction, the process comprising the steps of:cooling the feed gas;expanding the feed gas to form an expanded portion containing liquid;treating at least some of the expanded portion liquid in a fractionating column by flowing the expanded portion liquid downwardly in the column between a top and a bottom thereof in counter current fashion to vapors flowing up the column to separate the relatively less volatile fraction as column bottoms;wherein the fractionating column includes a main reboiler which heats and vaporizes a portion of the liquids flowing down the fractionating column to thereby provide stripping vapors which flow up the column; andwherein a portion of the relatively hot, methane rich feed gas entering the process is routed to a bottom section of the column to upset a normally existing vapor-liquid equilibrium and thereby strip out undesired ethane from the liquid.