Low temperature separation of hydrocarbon gas

Abstract

The invention provides a process for the separation of a heavier hydrocarbon fraction from a gaseous feed comprising a mixture of hydrocarbons, which process comprises subjecting the feed to a first fractionation to form a condensed product; subjecting the condensed product to a second fractionation, at a lower pressure than the first fractionation pressure, to provide the heavier hydrocarbon fraction and distillate fraction; and withdrawing the produced heavier fraction wherein the distillate from the second fractionation is partially condensed to provide reflux streams for both the first and second fractionations. Running the second fractionation at a lower pressure than the first means that there is phased let-down of pressure in two stages, leading to an increased pressure at the suction of the residue gas compressor and reduces power consumption. It also allows more efficient performance of the heat exchanger used to partially condense the reflux streams and simplifies the process, affording opportunities to better integrate process cooling and warming streams so increasing process efficiency. Increasing process efficiency reduces process power requirements or increases recovery of the desired heavier hydrocarbons or realizes both of these effects.

Dependencies are inferred from the claim text.