Apparatus for low temperature purification of gases

Apparatus useful for producing a substantially pure nitrogen stream from a gas stream containing nitrogen, hydrogen, carbon monoxide, carbon dioxide, water vapor and oxygen comprising:

• a) a first adsorption zone having an inlet and an outlet and containing an adsorbent which adsorbs moisture and carbon dioxide from a gas stream,
• b) a catalytic reaction zone having an inlet and an outlet and containing a catalyst which, in the presence of oxygen, converts carbon monoxide to carbon dioxide and hydrogen to water, the inlet of said catalytic reaction zone being in fluid communication with the outlet of said first adsorption zone,
• c) a second adsorption zone having an inlet and an outlet and containing an adsorbent which adsorbs moisture and carbon dioxide, the inlet of said second adsorption zone being in fluid communication with the outlet of said catalytic reaction zone,
• d) a cryogenic gas separation unit adapted to separate nitrogen from oxygen having an inlet in fluid communication with the outlet of said second adsorption zone, and
• e) conduit means connecting said cryogenic gas separation unit with at least one of said first and second adsorption zones for purging said first and second adsorption zones with a waste stream from said cryogenic separation unit.