US Patent 7537742 Process and adsorbent for hydrogen purification

This invention discloses an optimum set of adsorbents for use in H2-PSA processes. Each adsorbent bed is divided into four regions; Region 1 contains adsorbent for removing water; Region 2 contains a mixture of strong and weak adsorbents to remove bulk impurities like CO2; Region 3 contains a high bulk density (>38 lbm/ft3) adsorbent to remove remaining CO2; and most of CH4 and CO present in H2 containing feed mixtures; and Region 4 contains adsorbent having high Henry's law constants for the final cleanup of N2 and residual impurities to produce hydrogen at the desired high purity.