Patent ID: 7309378

Claim:
A process for purifying syngas comprising hydrogen and at least one gas selected from the group consisting of carbon monoxide and nitrogen, contaminated with impurities comprising H 2 O and carbon dioxide, said process comprising the following successive steps: a) passing the syngas to be purified through an adsorption zone comprising: adsorbent capable of selectively adsorbing carbon dioxide, which comprises at least one X zeolite of the faujasite type with an Si/Al ratio of 0.9 to 1.1 (NaLSX-type zeolite), at least 70% of the exchangeable sites of which are occupied by sodium ions, the rest of the cationic sites being occupied by a monovalent or polyvalent cation, at least one adsorbent, capable of selectively adsorbing each of other impurities except for CO 2 and H 2 O, at least one adsorbent capable of selectively adsorbing H 2 O, the adsorbents being either intimately mixed or in the form of separate beds in successive layers; and b) desorbing the carbon dioxide and the other impurity or impurities adsorbed on the adsorbent or adsorbents described in a) by increasing the temperature and/or reducing the pressure, and optionally recycling some of a first purified gas.