Carbon dioxide is removed from a raw gas containing hydrogen, carbon dioxide, and intermediate boiling gas, e.g. nitrogen, to give a gas suitable for use as a synthesis gas by a wet carbon dioxide removal process, and the resultant carbon dioxide depleted gas is subjected to pressure swing adsorption (PSA) to remove some, or all, of the intermediate boiling gas and the bulk of any residual carbon dioxide. The PSA waste gas is used to strip the absorbent liquid in the regeneration of the latter i...