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.

        1st 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.