Abstract: The present invention relates to a thermally regenerable adsorptive process for the purification of a feed air, wherein the feed air is contacted with a solid adsorbent to remove at least water and carbon dioxide, wherein, periodically, the solid adsorbent is thermally regenerated by contacting the solid adsorbent with a regeneration gas stream which is essentially free of at least water and carbon dioxide, wherein the regeneration gas is a nitrogen-enriched stream removed from an elevated pressure air separation unit fed with the purified feed air, characterized in that the removed nitrogen-enriched stream is compressed in a multiple staged compressor and that the regeneration gas is a portion of the nitrogen-enriched stream which is removed from an interstage of the multiple stage compressor and then contacted with the solid adsorbent.