A PROCESS FOR THE PREPARATION OF MOLECULAR SIEVE ADSORBENT FOR THE SIZE/SHAPE SELECTIVE ADSORPTION OF CARBON DIOXIDE FROM ITS GASEOUS MIXTURE WITH NITROGEN

摘要

A process for the size/shape selective adsorption of carbon dioxide from its gaseous mixture with nitrogen, especially, such as in the flue gas at ambient to elevated temperature with an adsorbent comprising A-type zeolite either pore engineered by the treatment of tetra alkyl alkoxide or exchanged with potassium ions up to a desired degree of total exchangeable sodium ions to preferentially adsorb carbon dioxide. The pore engineered adsorbent contain unit cell composition Na12[(A12O2)12(SiO2)12+x] 27 H2O where the value of ´x´ varies from 0.001 to 1.0 and potassium exchanged adsorbent must contain at least 15% to 50% potassium ions exchanged with sodium ions present in A-type zeolite. The carbon dioxide is thereafter removed from the adsorbent by pressure swing or applying vacuum or by heating the adsorbent above the adsorption temperature and recovering the carbon dioxide as a product stream.