Patent ID: 8202351

Claim:
a process for purifying or separating a feed gas stream containing hydrogen H.sub.2 and a molar carbon monoxide (CO) content greater than or equal to 1000 ppm, comprising: a) introducing the feed gas stream continuously into a first purification unit of the PSA type containing a first adsorbent on which CO is preferentially adsorbed, thereby producing an at least partially purified gas stream having an average molar CO content T less than or equal to Tacc, said at least partially purified gas stream having a CO content of less than or equal to 100 ppm, and periodically having a first maximum CO content TM.sub.0 greater than Tacc; b) recovering said at least partially purified gas; c) introducing said recovered at least partially purified gas continuously into a downstream adsorber containing at least one second adsorbent on which CO is preferentially adsorbed, thereby producing a gas enriched in H.sub.2 having an average CO content T and a maximum CO content TM.sub.1, both being less than or equal to Tacc; d) recovering said gas enriched in H.sub.2.