Process for treating pressurized gases to remove unwanted components

A process for treating an incoming gaseous mixture under pressure which includes methane, ethane, hydrogen, nitrogen and unwanted components of C.sub.3, C.sub.4 and C.sub.5 higher hydrocarbons, hydrogen sulphide and carbon dioxide, said process comprising fractionating at a pressure between the critical pressures of the individual hydrocarbon constituents and the lowest critical pressure of the liquid mixtures formed during fractionation such gaseous mixture to remove at least minor portions of higher hydrocarbons, hydrogen sulphide and carbon dioxide in a bottom product, scrubbing overhead product from said fractionation step to remove in a suitable solvent a substantial remainder of C.sub.3, C.sub.4 and C.sub.5 higher hydrocarbons, hydrogen sulphide and carbon dioxide from said overhead product to give a gaseous mixture essentially free of said unwanted components.