PATENTS

      137.     ------.  [BARR, F. T.]  (Standard Oil Development Co.).  Method and Apparatus for Solvent Cleaning Finely Divided Solids.  United States Patent 2,500,056.  Mar. 7, 1950; appl. filed Dec. 20, 1945.  Serial No. 636,246; 8 claims (Cl. 252-412).  Chem. Abs., vol. 44, 1950, p. 4168.

Gives process for reactivating fluid catalyst used in catalytic synthesis of hydrocarbons and oxygenated organic compounds from CO and H₂.  The powdered solids in a dry dense turbulent bed of fluid solids are subjected to the action of a continuous rotary filter.  The solids are picked from the fluidized bed in the form of a filter cake.  The cake is treated with solvents during the subsequent revolution of the filter.  The extract penetrating the filter material is continuously removed from the filter with the fluidizing gas.  Solids free of soluble deposit are taken off the filter surface by convention means before the return of the filter surface to the fluidized bed on its circular path.  Enough pressure differential is maintained across the filter material to permit ready formation of filter cake of desired thickness to allow the solvent to flow through the cake and filter at the desired speed and direction.  Hydrocarbon fractions produced in the synthesis may be used as solvent in dewaxing synthesis catalysts.

Gas feed rate----------2-10 cu. Ft. per lb. of solids feed

Gas velocity-----------0.1-0.5 ft. per sec.

Particle size------------15%-60% through 400-mesh

Solvent feed rate------10-30 lb. total. Including recycle;

205 lb. fresh per lb. of solids feed

Pressure differential------------2-10 p. s. i.

Drum rotation rate---------------------0.1-1.0 r. p. m.

1 foreign and 13 United States patents cited.