| abstract |
A method for recovering ethane, ethylene, propane, propylene and heavier hydrocarbon components from a hydrocarbon gas stream is disclosed. The stream is cooled and divided into first and second streams. The first stream is further cooled to condense substantially all of it, then expanded to the fractionation column pressure and fed to the fractionation column at the first mid-column supply location. The second stream is expanded to the tower pressure and then fed to the tower at the second mid-column feed position. The distillation stream is withdrawn from the tower below the feed point of the second stream and is then directed to heat exchange with the overhead steam stream to cool the distillation stream and condense at least a portion thereof to form a condensed stream. Form. At least a portion of the condensed stream is directed to the fractionation column as its top feed. The amount and temperature of the feed to the fractionation column is effective to maintain the overhead temperature of the fractionation column at a certain temperature, thereby recovering the majority of the desired components. |