2126.     ---------------.  [LOBO, W. E.]  Oxygen by Fractionation at Low Pressures.  Chem. Inds., vol. 59, No. 1, 1946, pp. 53-56; Chem. Abs., vol. 40, 1946, p. 5888.

        1^st successful low-pressure unit for liquid air fractionation built by the M. W. Kellogg Co. is described.  The M-7 unit produces O₂ by liquefaction and fractionation of air, operating at a maximum pressure of about 100 p.s.i.g.  The unit was designed to produce 1,000 std. c.f.h. of gaseous O₂ of 99.5% purity under the extreme atmospheric conditions of 120° F. ambient and 90° F. dew point, and to deliver the O₂, dry, in cylinders at 2,200 p.s.i.g.  The complete removal of the CO₂ and H₂O from the inlet air is accomplished without chemical treatment by condensation in a special reversing exchanger.  A diagrammatic flow sheet of the unit shows the 4 typical operating systems:  Air compression, refrigeration and air purification, fractionation, and O₂ compression.  Typical performance data also are plotted.