Abstract: The present invention provides a method of producing an oxygen-enriched air stream which includes compressing an air stream, dividing the compressed air stream into a first portion and a second portion, separating the second portion of the air stream to provide an oxygen gas product, introducing the oxygen gas product into the first portion of the compressed air stream to form an oxygen-enriched air stream, and then introducing the oxygen-enriched air stream to the process equipment, which may be by way of example a blast furnace.

Abstract: A method of producing gaseous oxygen in accordance with a variable demand cycle in which pumped liquid oxygen from a double column air separation unit is vaporized within a mixing column. During low demand phases, excess liquid oxygen is stored within a storage tank and used to augment the liquid oxygen to vaporized during the high demand phase. Reflux to the lower pressure column of the air separation unit is kept constant by storing liquid with column bottoms produced within the mixing column during the high demand phase for use in the low demand phase when less liquid oxygen is vaporized and therefore less column bottoms is produced in the mixing column.