Cryogenic air separation process and apparatus.
An energy efficient process and apparatus for the cryogenic separation of air by rectification to produce at least one vapor fraction, at least one liquid fraction, and at least one nitrogen product stream wherein cooled and pressurized feed air in vapor form is condensed by indirect heat exchange contact with at least one liquid fraction to vaporize the liquid fraction and condense the feed air stream, then vaporizing the condensed feed air stream by indirect heat exchange contact with at least one vapor fraction thereby condensing the vapor fraction, and then using the vaporized feed air stream as feed air for cryogenic separation by rectification.