PATENT

3547. ----- [STANDARD OIL CO.]  Removal of Wax Contaminants From Catalysts.  British Patent 614,406, Dec. 15, 1948.  Chem. Abs., vol. 43, 1949, p. 3994.

Soluble waxy and heavy hydrocarbon contaminants are removed from finely divided catalysts used in the production of hydrocarbons from CO and H2 by passing the catalyst material continuously as a slurry countercurrent to a stream of solvent, which has also been used to make the slurry.  The preferred operation involves the use of enough oil to form a slurry having 1-4 lb. catalyst per gal.  The mixer preferably is operated at 93°-121° and retains the slurry 0.25-2hr.  The slurry flows from the bottom of the mixer into the top of a set of vertical-tube washer elements arranged in parallel, and the catalyst settles through the solvent to the bottom.  For good washing conditions 0.01-1.0 gal. upward-flowing solvent is used per lb. of slurry, and the upward average liquid velocity ranges 0.1-1.5 in. per minute.  The length of the tube elements provides a washing time, which may range 0.5-6 hr.  Baffles in the tube elements are particularly effective in promoting contact between catalyst and solvent when the upward flowing solvent is introduced in surges.