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US 4,732,580 AGranted
Argon and nitrogen coproduction process
AssigneeThe BOC Group, Inc.
InventorsRavi Jain, Steven L. Lerner, Robert A. Mostello, Donald L. MacLean
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Abstract
Argon and nitrogen are produced in a basic two step process. In a first step, oxygen is removed from a compressed air feed using low temperature PSA (pressure swing adsorption). In the second step, argon and nitrogen mixture is separated by cryogenic distillation. The process yields crude liquid argon and very high purity gaseous nitrogen.
Claims25
A process for the coproduction of argon and nitrogen from an air stream comprising
- (i) elevating the pressure of said air stream in a compressor means;
- (ii) lowering the temperature of the compressed air stream in a first heat exchanger means;
- (iii) introducing the compressed and cooled air stream into a pressure swing adsorption unit comprising at least two adsorbent beds in order to remove oxygen and to yield a gaseous mixture comprising argon and nitrogen;
- (iv) separating the argon and nitrogen mixture by cryogenic means.
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A process for the coproduction of argon and nitrogen comprising
- (i) elevating the pressure of air in a compressor means;
- (ii) lowering the temperature of the compressed air in a first heat exchanger means;
- (iii) introducing the compressed and cooled air into a pressure swing adsorption unit comprising at least two adsorbent beds to remove oxygen and to yield a gaseous mixture comprising argon and nitrogen;
- (iv) introducing said argon and nitrogen mixture from said pressure swing adsorption unit into a second heat exchanger means to further cool said gases;
- (v) separating the argon and nitrogen mixture in a distillation column;
- (vi) refrigerating said distillation column with a heat-pump fluid stream which is successively passed through a compressor, said first heat exchanger means, said second heat exchanger means, a first Joule-Thomson means, and a turboexpander means to cool said heat pump stream;
- (vii) condensing said cooled heat-pump fluid stream in reboiler tubes of said distillation column;
- (viii) expanding and cooling the heat-pump fluid stream condensate in a second Joule-Thomson means;
- (ix) passing the heat-pump fluid successively through a third heat exchanger means, said second, and said first heat exchanger means to provide refrigeration prior to returning to said compressor means;
- and
- (x) passing the gaseous overhead product from said distillation column through said third, second and first heat exchanger means to recover its refrigeration.
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Dependencies are inferred from the claim text.