Separation of contaminated catalyst particles in a hydrocarbon conversion process

Claim 1

IN THE HYDROCARBON CONVERSION PROCESS WHEREIN HYDROCARBON VAPORS ARE CONTACTED WITH A SUSPENSION OF FINELY DIVIDED CONVERSION CATALYST CONSISTING ESSENTIALLY OF SOLID PARTICLES SMALLER THAN ABOUT 50 MESH AND WHEREIN THE CATALYST IS CIRCULATED FROM THE CONVERSION ZONE TO A REGENERATION ZONE AND THENCE BACK TO THE CONVERSION ZONE, THE IMPROVEMENT WHICH COMPRISES WITHDRAWING A RELATIVELY DENSE COLUMN OF THE FINELY DIVIDED CATALYST PARTICLES DOWNWARDLY FROM ONE OF THE AFORESAID ZONES, INJECTING A GAS INTO THE WITHDRAWN CATALYST COLUMN TO ACCELERATE THE FLOW OF THE RESULTING CATALYST SUSPENSION TO A VELOCITY BETWEEN ABOUT 30 TO 100 FEET PER SECOND, PASSING THE CATALYST SUSPENSION AT THIS VELOCITY THROUGH A CONFINED, ELONGATED PATH COMPRISING A CURVED SECTION OF ABOUT 5 TO 30 FEET RADIUS OF CURVATURE, THEREBY IMPARTING AN ABRUPT CHANGE IN DIRECTION OF CATALYST FLOW AND CREATING A CENTRIFUGAL FORCE