PROCESS FOR SEPARATING A GAS MIXTURE

A process for separating a gas mixture ( l) comprising the steps of cooling the mixture (19), feeding the cooled mixture (5) or a stream therefrom to a fractionating column (24), expanding at least a part of the column overhead product (7) in a spun flow in a nozzle (23), the flow being separated into a flow (8) enriched with components heavier than methane and a flow (9) depleted of said components, heating (19, 20) the depleted flow (9) at the expense of cooling the mixture, compressing the heated depleted gas flow in a compressor (26). The heated and compressed depleted gas flow is cooled in an air cooling apparatus (28), a part ( l 0) of the compressed and cooled depleted gas flow is used as an outgoing product (11), the other part (12) is additionally cooled (20), expanded (34), and fed to the column (24) and/or blended with the gaseous column overhead product (7) upstream of the nozzle (23).