Production of high purity oxygen from air

Abstract

Abstract PROCESS AND SYSTEM FOR PRODUCING HIGH PURITY OXYGEN BY AIR SEPARATION, WHICH INVOLVES USE OF A HIGH PRESSURE AIR FEED STREAM AND AN INTERMEDIATE PRESSURE AIR FEED STREAM, AND INCLUDES COOLING BOTH AIR FEED STREAMS APPROXIMATELY TO SATURATION, SEPARATING THE COOLED HIGH PRESSURE AIR STREAM INTO LIQUID NITROGEN AND A FIRST OXYGENRICH LIQUID AIR MIXTURE IN A FIRST SEPARATION ZONE, INTRODUCING A PORTION OF SAID LIQUID NITROGEN, AFTER REDUCING THE PRESSURE THEREOF, AS REFLUX INTO A MAIN DISTILLATION ZONE AT SLIGHTLY ABOVE ATMOSPHERIC PRESSURE, SEPARATING THE COOLED INTERMEDIATE PRESSURE AIR FEED STREAM IN AN INTERMEDIATE PRESSURE ZONE, INTO OVERHEAD NITROGEN AND A SECOND OXYGEN-RICH LIQUID AIR MIXTURE, REDUCING THE PRESSURE OF SUCH FIRST AND SECOND OXYGEN-RICH LIQUID AIR MIXTURES, AND INTRODUCING THE RESULTING OXYGEN-RICH LIQUID AIR MIXTURES AS FEED INTO THE MAIN DISTILLATION ZONE, WITHDRAWING NITROGEN OVERHEAD FROM THE INTERMEDIATE PRESSURE ZONE, MIXING SAME WITH A PORTION OF NITROGEN VAPOR FROM SAID FIRST SEPARATION ZONE, WORK EXPANDING THE RESULTING NITROGEN MIXTURE TO PROVIDE REFRIGERATION, AND PASSING THE RESULTING COOLED NITROGEN VAPOR INTO HEAT EXCHANGE RELATION WITH BOTH THE FIRST AND SECOND COMPRESSED AIR STREAMS FOR COOLING SAME, WITHDRAWING CRUDE LIQUID OXYGEN CONTAINING A MINOR PORTION OF ARGON FROM THE MAIN DISTILLATION ZONE, SEPARATING THE CRUDE LIQUID OXYGEN IN THE ARGON SEPARATION ZONE, INTO HIGH PURITY OXYGEN LIQUID AND AN ARGON-CONTAINING OVERHEAD, AND VAPORIZING THE HIGH PURITY OXYGEN PRODUCT; THE MAIN DISTILLATION ZONE, THE HIGH PRESSURE AND INTERMEDIATE PRESSURE SEPARATION ZONES, AND THE ARGON SEPARATION ZONE PREFERABLY BEING ASSOCIATED IN HEAT EXCHANGE RELATION TO PROVIDE SUITABLE CONDENSING AND REBOILING DUTY IN EACH OF SUCH ZONES, AND PREFERABLY UNDER CONDITIONS TO PROVIDE DIFFERENTIAL DISTILLATION IN THE MAIN DISTILLATION ZONE AND ALSO IN THE OTHER ABOVE-NOTED ASSOCIATED ZONES.

Inventors

• 👤 Michael L Hoffman

Bibliographic Details