Gas recovery.
CO2 is separated from a gas mixture containing medium boiling point gases, such as nitrogen, carbon monoxide, methane, and/or argon, and optionally also hydrogen by a pressure swing adsorption (PSA) process operated at above 50 DEG C. The PSA cycle preferably employs two or more depressurisation stages: the final stage, which is preferably counter-current, gives higher purity CO2 than the previous depressurisation stage or stages which are preferably co-current.