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US 5,036,672 AGranted
Process and apparatus for air fractionation by rectification
AssigneeLinde Aktiengesellschaft
InventorDietrich Rottmann
Life of this patent
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Abstract
A process and an apparatus are disclosed for air fractionation by means of rectification. Nitrogen (16) withdrawn from the process is heated to an intermediate temperature, withdrawn, in part (30), out of the primary heat exchanger (17), and engine-expanded (31). The resultant expanded gas (32) transfers its cold in the primary heat exchanger (17) to air to be fractionated (1) and is then recompressed (33, 36).
Claims27
In a process for air fractionation by rectification comprising cooling a compressed air stream;
- fractionating the cooled compressed air stream in a high pressure stage of a two-stage rectification to produce a nitrogen-rich fraction and an oxygen-rich liquid fraction;
- introducing at least a part of said nitrogen-rich fraction and said oxygen-rich liquid fraction into a low pressure stage of said two-stage rectification wherein they are separated into oxygen and nitrogen;
- at least one gaseous nitrogen fraction is removed from said low pressure stage and heated;
- and engine-expanding at least a part of said gaseous nitrogen fraction to produce work, wherein the improvement comprises:
- heating and recompressing at least a portion of resultant expanded nitrogen from said engine-expanding and utilizing at least a portion of said work obtained during expansion for recompression.
2 more elements
An apparatus for performing an air separation, comprising:
- a heat exchanger containing a passageway for air to be cooled and a passageway for nitrogen to be heated;
- a rectification column comprising a high pressure stage and a low pressure stage;
- a first conduit means for delivering cooled air from said heat exchanger to said high pressure stage;
- an expansion turbine having an inlet and an outlet;
- a compressor means having an inlet and an outlet;
- a second conduit means for removing a nitrogen fraction from an intermediate point of said heat exchanger and delivering said nitrogen fraction to said inlet of said expansion turbine;
- and
- a third conduit means connecting said outlet of said expansion turbine to said inlet of said compressor means and said third conduit means having a separate passageway through said heat exchanger.
5 more elements
Dependencies are inferred from the claim text.