Abstract: Process for separating at least carbon dioxide (CO2) contained in a gas stream, preferably air, in which at least carbon dioxide is adsorbed on a zeolite-X having a Si/Al ratio of approximately 1 to 1.5 and containing at most 35% of K+ cations, between 1 and 99% of Na+ cations and at most 99% of Ca2+ cations. This process is carried out at a temperature ranging from −40° C. to +80° C. Optionally, impurities chosen from water vapour and hydrocarbons, particularly ethylene, are also removed. The air thus purified is then capable of being cryogenically distilled.

Abstract: Process and apparatus for the purification of a gaseous flow containing at least one impurity which can be carbon dioxide, water vapor and/or hydrocarbon. The impurity is adsorbed on a bed of adsorbent containing at least one adsorbent material, it being possible to use stacked adsorbent beds. Atop the uppermost bed is a layer of particulate ballast having a density greater than that of the adsorbent. The bed of ballast exerts a mechanical pressure on the subjacent adsorbent and prevents fluidization of the upper portion of the subjacent adsorbent. As a result, the rate of gas flow through the adsorbent can be increased.

Abstract: Process for purifying an air flow containing carbon dioxide (CO.sub.2) and water vapour, in which at least some of the CO.sub.2 and water vapour impurities are removed by adsorbing the impurities on at least one calcined alumina containing at most 10% by weight of at least one alkali or alkaline-earth metal oxide, the adsorption being carried out at a temperature of between -10.degree. C. and 80.degree. C.