Air separation
AssigneeThe BOC Group, Inc.
InventorChristopher J. Hine
Life of this patent
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Abstract
Air is compressed in a compressor, pre-purified in an unit, and cooled in a heat exchanger. The resulting flow of air is subjected to a first rectification in a double rectification column so as to separate the air into an oxygen-rich fraction and a nitrogen-rich fraction. A further oxygen fraction, enriched in argon, is withdrawn from the double rectification column and is introduced into the bottom of a second rectification column in which relatively pure argon is separated from the oxygen. A stream of relatively impure argon is supplied from an independent source to an intermediate region of the second rectification column through an inlet thereof.
Claims5
A method of separating air comprising;
- compressing, pre-purifying and cooling air;
- subjecting resulting air to a first rectification in which the air is separated into a nitrogen-rich fraction and an oxygen-rich fraction;
- withdrawing a further oxygen fraction, enriched in argon from the first rectification, and subjecting the further oxygen fraction to a second rectification in which relatively pure argon is separated from oxygen;
- and
- supplying from an independent source to an intermediate location of the second rectification a stream of relatively impure argon comprising argon, oxygen and nitrogen.
An apparatus for separating air comprising;
- means for compressing, pre-purifying and cooling air;
- at least one first rectification column for separating resulting air into a nitrogen-rich fraction and an oxygen-rich fraction;
- said at least one first rectification column having an outlet for a further oxygen fraction, enriched in argon, communicating with a first inlet of a said at least one second rectification column;
- the said at least one second rectification column having a second inlet at an intermediate location thereof communicating with an independent source of relatively impure argon.
Dependencies are inferred from the claim text.