Patent ID: 6391092
Filing Date: 2002-05-21
Classification: B01D,Y02C,Y10S

Abstract:
A process for the removal of impurties from a gas stream by thermal swing adsorption comprising sequentially passing said gas stream through a first adsorbent layer which will remove water from said gas stream, a second adsorbent layer comprising a sodium X zeolite thereby removing CO2 from said gas stream, and a third adsorbent layer comprising a calcium Low Silicon X zeolite wherein the adsorbents in said second and third layers have a Si/Al elemental ratio of the zeolitic phase between 0.9 to 1.3, and 0.9 and 1.15, respectively, with a cation composition of the third layer adsorbent, on an equivalent basis, that comprises about 60 to about 100% calcium ions, and about 40 to about 0% other ions, the other ions being selected from the group consisting of Group IA ions, from Group IIA ions other than calcium, from Group IB ions other than gold, from Group IIB ions other than mercury, and from ions of the lanthanides, and mixtures of these, and said third layer adsorbent comprises about 5 to about 25 percent by weight of binder, thereby removing nitrogen oxides and hydrocarbons from said gas stream.