Abstract: The gaseous mixture to be split is dehydrated and condensed under a high pressure by sending the gases, separated in a first separator (4), to the first stage of an expansion turbine (16) and the condensates are sent to a fractionating column (49), the gases exiting the first stage of the turbine are mixed with the gases exiting a second separator (19), said mixture being sent to a third separator (26) the bottom liquid whereof is sent to the column (49), and the separated gas is mixed with the head gas of the column (49), whereafter it is cooled and sent to a medium-pressure fourth separator (32). The gas coming from the latter separator (32) feeds the second stage of the turbine (16) while the condensate is admixed with the gas discharged from the second stage and sent to an ultimate low-pressure separator (41) wherefrom the condensate is sent to the column (49) head and the residual gas is cooled and compressed (43, 44), the condensates being recovered from the bottom of the column (49).

Abstract: To recover condensates from natural gas the raw gas is sent to a high-pressure separator (4) and the incondensable gas is sent to the first stage of an expansion turbine (16) and expanded to a pressure nearly equal to that of the head of a fractionation column (25, 28, 29) composed of three sections, top (25), intermediate (29) and bottom (28). The liquids from the separator (4) are expanded in a second separator (14) and fed to the bottom section (28). The gas from the second separator (14) is mixed with the exhaust from the first turbine stage (16) and fed to the lower portion of the top section (25) to the head of which there is sent the liquid issuing from the intermediate section (29). The latter receives the exhaust from the second turbine stage (36) which is fed by the gas from the top section (25) head. The liquid on the bottom of the top section (25) is fed to the bottom section (28 ).