Abstract: The invention relates to a method for prepurifying air by means of adsorption, using two adsorption recipients operating alternately, in parallel, and in a TSA cycle, each recipient containing an adsorbent arranged on a radial adsorption bed, and each adsorption cycle consisting of (a) an adsorption stage during which the impurities are eliminated on the adsorbent at an adsorption temperature (rads), the air crossing the adsorption bed in a centripetal manner; (b) a regeneration stage during which the adsorbent is regenerated by flushing with a regeneration gas at a regeneration temperature (Treg), such as Treg>Tads, in order to desorb the impurities; et (c) an adsorbent cooling stage during which the temperature of the regenerated adsorbent is reduced. The maximum duration (rads) of the adsorption is 120 minutes, preferably between 60 and 120 minutes. The regeneration gas is introduced in such a way that it flushes the bed containing the adsorbent in the centrifugal direction.