Patent ID: 7069744

Claim:
A process for separating a gas stream containing methane, C2 and C3 components and heavier hydrocarbons into a volatile gas fraction containing substantially all of the methane and C2 components and a less volatile fraction containing a large portion of C3 components and heavier hydrocarbons, the process comprising the steps of: a. supplying and cooling a gas stream to partially condense at least a portion of the gas stream to produce a first vapor stream and at least a first liquid stream; b. preheating at least a portion of the first liquid stream and then sending the portion of the first liquid stream to a distillation tower, the distillation tower producing a tower overhead stream containing mainly methane and C2 components and a tower bottoms stream containing a majority of the C3 components and heavier hydrocarbons; c. cooling and partially condensing the tower overhead stream thereby producing a second vapor stream and a liquid hydrocarbon stream, the liquid hydrocarbon stream being sent to the distillation tower as a top feed; d. expanding the first vapor stream and sending the first vapor stream to an absorber column having at least one mass transfer zone as a bottom absorber feed streamthereby producing an absorber overhead stream containing essentially all methane, C2 and lighter components of the gas stream and an absorber bottoms stream; e. preheating at least a portion of the absorber bottoms stream and sending the portion of the absorber bottoms stream into the distillation tower as a middle tower feed stream; f. cooling and condensing at least a portion of the second vapor stream thereby forming a first lean reflux stream and sending the first lean reflux stream to the absorber as an absorber top feed stream; g. heating the absorber overhead stream, compressing, and discharging the absorber overhead stream as a residue gas stream; and h. wherein the improvement comprises cooling and at least partially condensing the portion of the residue gas stream thereby producing a second lean reflux stream and then sending the second lean reflux stream to the absorber column.