Patent ID: 6393866
Filing Date: 2002-05-28
Classification: F25J,Y10S

Abstract:
A method for carrying out cryogenic air separation comprising:(A) separating feed air within a higher pressure column by cryogenic rectification to produce nitrogen-enriched vapor and oxygen-enriched fluid, passing oxygen-enriched fluid from the higher pressure column into a lower pressure column, and producing by cryogenic rectification oxygen-rich liquid within the lower pressure column; (B) passing nitrogen-enriched vapor into a plurality of vertically oriented tubes, said tubes each having a fluted internal surface and an outer surface having a plurality of cavities; (C) passing nitrogen-enriched vapor downwardly within the tubes, passing oxygen-rich liquid downwardly along the outer surfaces of the tubes, and condensing nitrogen-enriched vapor by indirect heat exchange with partially vaporizing oxygen-rich liquid to produce oxygen-rich vapor and remaining oxygen-rich liquid; and (D) recovering at least some of at least one of the oxygen-rich vapor and remaining oxygen-rich liquid as product oxygen.