Purification of air

A process for removing water, carbon dioxide and nitrous oxide from a feed air stream prior to cryogenic distillation of the air stream to separate a nitrogen rich stream and/or an oxygen rich stream, comprising passing said feed air stream containing water, carbon dioxide and nitrous oxide through a first adsorbent to adsorb said water, through a second adsorbent which optionally may be the same as the first adsorbent to remove carbon dioxide and through a third adsorbent to remove said nitrous oxide from said air stream, wherein said third adsorbent is calcium exchanged X zeolite, Na mordenite, Ba exchanged X zeolite, or binderless Ca exchanged X zeolite.

A process for air separation comprising removing water, carbon dioxide and nitrous oxide from a feed air stream by passing said feed air stream containing water, carbon dioxide and nitrous oxide through a first adsorbent to adsorb said water, through a second adsorbent which optionally may be the same as said first adsorbent to remove carbon dioxide and through a third adsorbent present to remove said nitrous oxide from said air stream and conducting cryogenic distillation of the purified air stream to separate a nitrogen rich stream and/or an oxygen rich stream, wherein said third adsorbent has a Henry's Law selectivity for nitrous oxide compared to carbon dioxide of 0.49 or more at 30.degree. C.

Apparatus for removing water, carbon dioxide and nitrous oxide from a feed air stream prior to cryogenic distillation of said feed air stream to separate a nitrogen rich stream and/or an oxygen rich stream, comprising in fluid series connection a first adsorbent to adsorb said water, a second adsorbent to remove said carbon dioxide and a third adsorbent to remove said nitrous oxide from said feed air stream, wherein said third adsorbent has a Henry's Law selectivity for nitrous oxide compared to carbon dioxide of 0.49 or more at 30.degree. C.

Apparatus for air separation comprising a purification unit comprising in fluid series connection a first adsorbent to adsorb water, a second adsorbent to remove carbon dioxide and a third adsorbent to remove nitrous oxide from a feed air stream, wherein said third adsorbent has a Henry's Law selectivity for nitrous oxide compared to carbon dioxide of 0.49 or more at 30.degree. C., and a cryogenic air separation unit for separating nitrogen from oxygen in said feed air stream after the removal of said water, carbon dioxide and nitrous oxide in said purification unit.