PATENT

3490. ----- [STANDARD OIL CO.]  [Fluidized Catalyst Bed.]  French Patent 937,565, Aug. 20, 1948.  Chem. Abs., vol. 44, 1950 p. 317.

To achieve a high fluidity of the bed and to have a maximum mass of particles per unit volume, the catalyst is made to contain at least 35% of 70-200 microns, 30-40% of 20-70 microns, and preferably none of 0-20 microns.  The maximum value of 70-200 microns is 60-70%.  Thus in catalytic cracking using Al₂O₃ on silica gel with 100% catalyst at 20-70 microns, the density of the bed will be 195 kg. per m.³ for a speed of 60 cm. per sec. and 150 kg. per m.³ for a speed of 42 cm. per sec.  With 60% of 20-70 microns and 40% of 70-200 microns, the density is 240-300 kg. per m.³ for equivalent speeds.