A method for the production of argon free oxygen by rectification of air

摘要

Nitrogen- and argon-free oxygen is recovered from air by a three-stage rectification system in which the third stage is maintained at an absolute pressure of 0.8 to 1.1 atmosphere while the pressure of the second stage is higher by only 0.3 to 0.5 atmosphere. A side stream containing argon flows from the second rectifying stage to the third stage which yields a head product enriched in argon. This head product is pumped back into the upper portion of the second stage. High-purity oxygen is recovered from the sumps of the second and third rectifying stages.