| 摘要 |
<p>A process for the purification of synthesis gas polluted by carbon dioxide (CO2) and one or more other impurities, comprises stages of passage of the gaseous mixture through an adsorption zone containing a zeolite and other adsorbents, desorption of the CO2 and other impurities, and re-pressurizing by introduction of a current of purified gas. The process comprises one or more cycles of the following sequence of stages: (a) passage of the gaseous mixture in an adsorption zone comprising a selective adsorbent for CO2 comprising a zeolite X of faujasite type with a silicon/aluminum (Si/Al) ratio of about 1 (preferably 0.9-1.1, more preferably 1-1.05) of which at least 70% (preferably at least 90%) of the exchangeable sites are occupied by sodium (Na) ions, the remainder of the cationic sites being occupied by potassium (K), calcium (Ca) or other mono- and/or polyvalent cations (magnesium (Mg), strontium (Sr), barium (Ba), lanthanides or rare earths), one or more adsorbents being able to selectively adsorb other impurities such as water, hydrocarbons and/or nitrogen oxides (NOx), the adsorbents being either intimately mixed or as distinct successive beds; (b) desorption of CO2 and other adsorbed impurities by setting up a temperature increase and/or pressure decrease, the stage being completed by a purge phase comprising a recycling of part of the purified gas; and (c) re-pressurizing of the adsorption zone by introduction of a current of purified gas and/or cooling of the zone by sweeping with purified cold gas.</p> |
