Adsorption-desorption process for the recovery of hydrogen

摘要

An adsorption-desorption process for the recovery of hydrogen from a feed gas containing trace pollutants adapted to be strongly adsorbed, in concentrations generally below 1% by volume and containing components adapted for only light adsorption, in concentrations above 1% by volume is operated through a preliminary first adsorption stage for the strongly adsorbable trace pollutants and a second main adsorption stage for the light adsorbable components and for the discharge of hydrogen. Contrary to the prior art where the adsorption-desorption was effected by alternating high pressure and low pressure cycles in the main adsorption stage only, the pressure cycles in the present case are carried out both in the preliminary first adsorption stage and in the second main adsorption stage, preferably by arranging the two adsorption states in series. The process substantially extends the service time of the adsorber used in the first adsorption stage.