Air separation with temperature and pressure swing

A continuous process for separating air into oxygen and nitrogen comprising the repeated steps of contacting feed air with an oxygen acceptor mixture of alkali metal nitrite and nitrate salts in an absorption zone at relatively low temperature and pressure to absorb oxygen from the feed air and oxidize the acceptor, removing an oxygen-depleted nitrogen-rich stream from the absorption zone, pumping the oxidized acceptor to an elevated pressure, separately releasing the absorbed oxygen from the acceptor at elevated temperature and the elevated pressure in a desorption zone so as to regenerate the oxygen acceptor and generate high pressure product oxygen and recycling the oxygen acceptor to the absorption zone after reducing its temperature and pressure to absorpation zone conditions.