Abstract: There is provided a process for the separation of a gaseous feed comprising a mixture of nitrogen, hydrocarbons and at least 0.005 mol % carbon dioxide, the process comprising: (i) cooling and at least partially condensing the gaseous feed, and (ii) separating in one or more stages the cooled and at least partially condensed gaseous feed into a hydrocarbon rich product stream low in nitrogen and a nitrogen rich reject stream low in hydrocarbons, and wherein refrigeration is provided to one or more stages of the separation process by a heat pump system in which a heat pump refrigerant fluid is compressed and subsequently expanded at one or more pressure levels below the condensing pressure, and subsequently heated in heat exchange with the gaseous feed and/or one or more streams generated by the separation process to provide refrigeration thereto; and further wherein at least part of the heated refrigerant is recycled through the heat pump system.

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.