Abstract: There is disclosed a process and apparatus for recovering ethane and heavier hydrocarbons from natural gas by heating the natural gas stream prior to the expansion and introduction thereof into a demethanizer operating under cryogenic conditions. Ethane and the heavier hydrocarbons are recovered from the demethanizer as well as a residual gaseous methane stream which is compressed to a pipeline receiving pressure by the work of expansion without requiring a booster compressor.

Abstract: Natural gas, containing carbon dioxide and nitrogen, is demethanized in a first fractional distillation tower to provide an overhead of nitrogen and methane free of carbon dioxide and components heavier than methane. A sidestream is withdrawn from the first tower at a point therein where carbon dioxide concentration is maximized and the sidestream is fractionated in a second tower to recover methane and carbon dioxide as overhead. Nitrogen is rejected from the carbon dioxide free overhead from the first tower by liquefaction of methane to provide a send-out gas free of nitrogen. The cold potential of various streams is used to provide cooling requirements for the process.