| abstract |
A pressure swing adsorption process is described, in which a gas mixture which contains a readily adsorbable gas component to be recovered and a less readily adsorbable gas component is introduced at low pressure into an adsorption zone, the pressure being increased before the less readily adsorbable gas component is flushed from the adsorption zone at high pressure. In a subsequent pressure reduction, the readily adsorbable gas component is obtained with an improved degree of purity. If a plurality of adsorption zones are employed, each zone in turn passes through the low-pressure adsorption, the increase in pressure, the high-pressure elution and the pressure reduction, pressure equalisation phases being preferably provided between the zones which must be pressurised subsequent to the adsorption and the pressure of which must be reduced subsequent to the elution. The process is suitable, inter alia, for producing nitrogen of improved purity from air and for producing highly pure methane from mixtures of methane and nitrogen. <IMAGE> |