The equipment, for example of the PSA type, comprises gas circulation elements for passing the gas horizontally through an adsorbent (3), which comprise, on at least one vertical side of the adsorbent, a gas distribution volume comprising a first subvolume (5; 9) adjacent to the adsorbent, and a second subvolume (6; 10) separated from the first subvolume by a wall provided with passages (40) having cross-sections and/or a distribution which are selected so as to reduce the variations in local flow rate along the adsorbent. The equipment is particularly useful in separating gases from air.