Patent ID: 6418753
Filing Date: 2002-07-16
Classification: F25J,Y10S

Abstract:
A process for the low-temperature fractionation of air comprising introducing compressed and prepurified feed air (3, 5) into a rectification system for nitrogen-oxygen separation, which system has a pressure column (6), feeding at least a part of the compressed and prepurified feed air (5) to a feed point in the pressure column (6), withdrawing an oxygen-enriched fraction (13) in the liquid state from at least one theoretical or actual plate (15) above said feed point and passing (14), said oxygen-enriched fraction (13) to a further working step (7) within the rectification system, withdrawing a purge fraction of feed air enriched in low volatility constituents (16) in the liquid state from the bottom of the pressure column (6) at a point below said feed point, feeding said purge fraction in the liquid state to a purification stage (17) to remove N2O and withdrawing a purified fraction (18) from the purification stage (17).