METHOD FOR LOW-TEMPERATURE SEPARATION OF HYDROCARBON GAS Russian patent published in 2010 - IPC F25J3/00 

FIELD: process engineering.

SUBSTANCE: invention relates to hydrocarbon gas processing by low-temperature condensation and can be used in oil-and-gas processing industry. Proposed method comprises feeding prepared and cooled hydrocarbon gas flow to first fractionation stage to produce gas phase enriched with methane and condensate to be fed to second fractionation stage, produced deethanisation gas phase and liquid phase enriched with heavy hydrocarbons C_3+higher being diverted. Produced deethanisation gas phase is cooled and separated into deethanisation gas and liquid phase to be fed to irrigate second fractionation stage. Deethanisation gas is cooled by top product of the first fractionation stage and fed, as concentrated, to first fractionation stage for irrigation. Note here that, prior to deethanisation gas cooling by said top product of the first fractionation stage, is it additionally cooled by heat exchange with first stage bottom zone flow.

EFFECT: increased extraction of fraction C_3+higher from hydrocarbon gas.

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