Method and apparatus for recovering oxygen at hyperbaric pressure

Abstract

An method for the recovery of oxygen at hyperbaric pressure by low-temperature air fractionation includes compressing feed air to a first pressure, which is about the same as the operating pressure of the pressure column. At least a first partial flow of the feed air is cooled in a main heat exchanger and passed into the pressure column. An oxygen flow is tapped from the low-pressure column; brought to a delivery pressure that is higher than the operating pressure of the low-pressure column; heated in the main heat exchanger; and discharged as product. The pressure of a process stream from the main heat exchanger is relieved in a work-expanding manner, and the process stream is supplied to the low-pressure column. At least a portion of the mechanical energy generated by the work-expanding is used to drive a cold compressor. The flow of liquid oxygen from the low-pressure column is brought to the delivery pressure, and the oxygen is then evaporated by indirect heat exchange with a second partial flow of feed air, which has been compressed to the first pressure. The second partial flow is brought to a second pressure by the cold compressor upstream of the indirect heat exchange.

Dependencies are inferred from the claim text.