(JP9505515-W)      A feed gas is sepd. into a first supply component (I) and a second supply component (II), (I) having a higher b.pt. than (II), by: (a) providing a first sepn. vessel and a second sepn. vessel arranged such that (I) moves upwardly to the top of the respective vessel as gas and (II) moves downwardly to the bottom of the respective vessel as liq., (b) supplying the feed gas to one of the sepn. vessels, (c) transferring liq. from the bottom of the first vessel to the second vessel and gas from the top of the second vessel to the first vessel and (d) extracting gas from the top of the first vessel as (I) and extracting liq. from the bottom of the second vessel as (II). A recycle fractionator vessel is provided separate from the vessel and the gas is transferred from the top of the second vessel to the recycle vessel and condensed to liq.. The gas is extracted from the top of the recycle vessel and transferred to the first vessel and the liq. is extracted from the bottom of the recycle vessel and transferred to the second vessel.    USE -   Thermodynamic sepn. of gases into components of different b.pt., esp. ethane, methane, propane or CO2 from natural gas.    ADVANTAGE -   Provides improved sepn., thermodynamic efficiencies and improved mixing and heat transfer. Avoids the use of costly turbo-expanders. Needs less energy and less capital cost. Provides improved process control and optimal prod. recovery.    (EP721557-B1)      A feed gas is sepd. into a first supply component (I) and a second supply component (II), (I) having a higher b.pt. than (II), by: (a) providing a first sepn. vessel and a second sepn. vessel arranged such that (I) moves upwardly to the top of the respective vessel as gas and (II) moves downwardly to the bottom of the respective vessel as liq., (b) supplying the feed gas to one of the sepn. vessels, (c) transferring liq. from the bottom of the first vessel to the second vessel and gas from the top of the second vessel to the first vessel and (d) extracting gas from the top of the first vessel as (I) and extracting liq. from the bottom of the second vessel as (II). A recycle fractionator vessel is provided separate from the vessel and the gas is transferred from the top of the second vessel to the recycle vessel and condensed to liq.. The gas is extracted from the top of the recycle vessel and transferred to the first vessel and the liq. is extracted from the bottom of the recycle vessel and transferred to the second vessel.    USE -   Thermodynamic sepn. of gases into components of different b.pt., esp. ethane, methane, propane or CO2 from natural gas.    ADVANTAGE -   Provides improved sepn., thermodynamic efficiencies and improved mixing and heat transfer. Avoids the use of costly turbo-expanders. Needs less energy and less capital cost. Provides improved process control and optimal prod. recovery.    (RU2134386-C1)      A feed gas is sepd. into a first supply component (I) and a second supply component (II), (I) having a higher b.pt. than (II), by: (a) providing a first sepn. vessel and a second sepn. vessel arranged such that (I) moves upwardly to the top of the respective vessel as gas and (II) moves downwardly to the bottom of the respective vessel as liq., (b) supplying the feed gas to one of the sepn. vessels, (c) transferring liq. from the bottom of the first vessel to the second vessel and gas from the top of the second vessel to the first vessel and (d) extracting gas from the top of the first vessel as (I) and extracting liq. from the bottom of the second vessel as (II). A recycle fractionator vessel is provided separate from the vessel and the gas is transferred from the top of the second vessel to the recycle vessel and condensed to liq.. The gas is extracted from the top of the recycle vessel and transferred to the first vessel and the liq. is extracted from the bottom of the recycle vessel and transferred to the second vessel.    USE -   Thermodynamic sepn. of gases into components of different b.pt., esp. ethane, methane, propane or CO2 from natural gas.    ADVANTAGE -   Provides improved sepn., thermodynamic efficiencies and improved mixing and heat transfer. Avoids the use of costly turbo-expanders. Needs less energy and less capital cost. Provides improved process control and optimal prod. recovery.    (US6098425-A)      A feed gas is sepd. into a first supply component (I) and a second supply component (II), (I) having a higher b.pt. than (II), by: (a) providing a first sepn. vessel and a second sepn. vessel arranged such that (I) moves upwardly to the top of the respective vessel as gas and (II) moves downwardly to the bottom of the respective vessel as liq., (b) supplying the feed gas to one of the sepn. vessels, (c) transferring liq. from the bottom of the first vessel to the second vessel and gas from the top of the second vessel to the first vessel and (d) extracting gas from the top of the first vessel as (I) and extracting liq. from the bottom of the second vessel as (II). A recycle fractionator vessel is provided separate from the vessel and the gas is transferred from the top of the second vessel to the recycle vessel and condensed to liq.. The gas is extracted from the top of the recycle vessel and transferred to the first vessel and the liq. is extracted from the bottom of the recycle vessel and transferred to the second vessel.    USE -   Thermodynamic sepn. of gases into components of different b.pt., esp. ethane, methane, propane or CO2 from natural gas.    ADVANTAGE -   Provides improved sepn., thermodynamic efficiencies and improved mixing and heat transfer. Avoids the use of costly turbo-expanders. Needs less energy and less capital cost. Provides improved process control and optimal prod. recovery.