Process and apparatus for air separation by rectification

Patent 4824453 Issued on April 25, 1989. Estimated Expiration Date:

July 11, 2008. Estimated Expiration Date is calculated based on simple USPTO term provisions. It does not account for terminal disclaimers, term adjustments, failure to pay maintenance fees, or other factors which might affect the term of a patent.

Abstract Claims Description Full Text

Patent References

2280383

3688513

Process for low-temperature separation of air
Patent #: 4137056
Issued on: 01/30/1979
Inventor: Golovko

Air separation with medium pressure enrichment
Patent #: 4433989
Issued on: 02/28/1984
Inventor: Erickson

Low energy high purity oxygen plus argon
Patent #: 4578095
Issued on: 03/25/1986
Inventor: Erickson

High pressure oxygen pumped LOX rectifier Patent #: 4604116
Issued on: 08/05/1986
Inventor: Erickson

Inventors

Assignee

Linde Aktiengesellschaft

Application

No. 07/217516 filed on 07/11/1988

US Classes:

62/648, Downstream operation62/924Argon

Examiners

Primary: Warner, Steven E.

Attorney, Agent or Firm

Millen & White

International Class

F25J 3/04 (20060101)

Foreign Application Priority Data

1987-07-09 DE

Abstract

In 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.