Patent ID: 9212849
Filing Date: 2015-12-15
Classification: F25J

Abstract:
1. An apparatus for separating air comprising: a main air compressor for compressing the air; a purification system connected to the main air compressor for purifying the air and thereby producing a compressed and purified air stream; a booster compressor in flow communication with the purification unit such that a first compressed air stream is produced from at least part of the compressed and purified air stream and a second compressed air stream is produced by compressing another part of the compressed and purified air stream in the booster compressor to a higher pressure than the first compressed air stream; a main heat exchanger configured to cool at least part of the first compressed air stream and to condense the second compressed air stream and form a liquid air stream through indirect heat exchange with return streams produced by a distillation column system; the distillation column system having a higher pressure column in flow communication with the main heat exchanger so as to receive the at least part of the first compressed air stream, a lower pressure column operatively associated with the higher pressure column in a heat transfer relationship, a crude argon column connected to the lower pressure column to rectify an argon-oxygen containing vapor stream withdrawn from the lower pressure column and thereby, at least in part, produce a crude argon stream and an argon refining column to rectify the crude argon stream and thereby forming an argon product stream from an argon-rich liquid column bottoms produced in the argon refining column; the argon refining column having a bottom reboiler in flow communication with the main heat exchanger to receive the liquid air stream, thereby subcooling the liquid air stream and reboiling the argon refining column; a reflux conduit configured for directing a first part of the subcooled liquid air stream from the bottom reboiler of the argon refining column as an intermediate reflux stream to an intermediate location of the higher pressure column; and the reflux conduit is further configured for directing a second part of the subcooled liquid air stream from the bottom reboiler of the argon refining column as a second intermediate reflux stream to the lower pressure column at a level thereof above where all or any part of a crude liquid oxygen stream composed of a crude liquid oxygen column bottoms of the higher pressure column is introduced.