Process for low-temperature separation of air
Air separation with medium pressure enrichment
Low energy high purity oxygen plus argon
High pressure oxygen pumped LOX rectifier Patent #: 4604116
ApplicationNo. 07/217516 filed on 07/11/1988
US Classes:62/648, Downstream operation62/924Argon
ExaminersPrimary: Warner, Steven E.
Attorney, Agent or Firm
International ClassF25J 3/04 (20060101)
Foreign Application Priority Data1987-07-09 DE
AbstractIn a process and apparatus for air separation by rectification air 1 is preliminarily separated in a first rectification stage 2 of a two-stage rectification column to obtain a nitrogen-rich fraction 4 and an oxygen-rich fraction 8. These two fractions are fed to the second rectification stage 6 and separated into oxygen and nitrogen fractions. An argon-enriched fraction, containing essentially oxygen and argon, is removed from the second rectification stage at an intermediate point and is separated in a raw argon column 10 by rectification into an argon-rich fraction 18 and a liquid fraction 19 containing essentially oxygen. The liquid fraction 19 is fed back into the second rectification stage. Another fraction 22 is removed from the raw argon column above the bottom thereof and is separated in a high-purity oxygen column 23 to produce a high-purity oxygen fraction 25, 26 and a lighter residual fraction 24. An additional nitrogen-rich fraction is removed from the head of the first rectification stage and separated in a high-purity nitrogen column 31 producing a bottom liquid fraction 29, which is fed back to the head of the first rectification stage, and a residual gas fraction 33. A high-purity nitrogen fraction 34 is removed at a point several plates below the head of the first rectification stage.