| 摘要 |
A process is described for separating the heavier hydrocarbons from a gaseous hydrocarbon feed wherein a first separator is employed to separate partially condensed gaseous feed and wherein the vapour portion undergoes work expansion and is fed to a fractionation column. The liquid portion is subcooled in heat exchange with the overhead vapour from the fractionation column, expanded, evaporated to provide refrigeration at a low temperature level, and fed to the fractionation column. The rewarmed residual vapour is subsequently compressed to a pressure suitable for export, with a portion of the compressed gas being cooled, condensed and recycled back to reflux the top section of the fractionation column.Also described is a process wherein a first separator is employed to separate partially condensed gaseous feed and wherein the vapour portion undergoes work expansion and is fed to a high pressure wash column. The liquid portion is expanded and fed to the base of the high pressure wash column. Bottoms liquid from the wash column is subcooled in heat exchange with the overhead vapour from a fractionation column, expanded, evaporated to provide refrigeration at a low temperature level, and fed to the fractionation column. Vapour from the high pressure wash column is partially condensed, with the liquid portion used to provide reflux to the high pressure wash column and the fractionation column.The processes are especially applicable to recovery of ethane and heavier components from natural gas. Overall process power requirements are reduced, recovery of the desired heavy hydrocarbons is increased or both of these effects are realised.
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