Abstract: An air separation method and apparatus in which a supercritical oxygen product is produced by heating a pumped liquid oxygen stream having a supercritical pressure, through indirect heat exchange with a boosted pressure air stream. The indirect heat exchange is conducted within a heat exchanger and a liquid nitrogen stream is vaporized in the heat exchanger to depress the pressure that would otherwise be required of the boosted pressure air stream to heat the pumped liquid oxygen stream. The pumped liquid oxygen stream constitutes 90 percent of the oxygen-rich liquid removed from an air separation unit in which the air is rectified, the liquid nitrogen constitutes at least 90 percent of the liquid nitrogen that is not used as reflux and a flow-rate ratio between the liquid nitrogen stream and the oxygen-rich liquid is between about 0.3 and 0.90.

Abstract: An air separation method and apparatus in which a supercritical oxygen product is produced by heating a pumped liquid oxygen stream having a supercritical pressure, through indirect heat exchange with a boosted pressure air stream. The indirect heat exchange is conducted within a heat exchanger and a liquid nitrogen stream is vaporized in the heat exchanger to depress the pressure that would otherwise be required of the boosted pressure air stream to heat the pumped liquid oxygen stream. The pumped liquid oxygen stream constitutes 90 percent of the oxygen-rich liquid removed from an air separation unit in which the air is rectified, the liquid nitrogen constitutes at least 90 percent of the liquid nitrogen that is not used as reflux and a flow-rate ratio between the liquid nitrogen stream and the oxygen-rich liquid is between about 0.3 and 0.90.