regenerating gas passed to pipes 18 then passes out through holes or nozzles along the bottom surface of the pipes and then upwardly through the bed 19 of catalyst to be regenerated under dense fluid phase regeneration conditions regenerated catalyst is withdrawn from the vessel above the grid by the inlet 8 communicating with conduit 6 the inlet to withdrawal conduit 6 may be as shown in fig2 or it may be extended upwardly into the vessel so that regenerated catalyst is withdrawn from an upper portion of the dense fluid bed 19 of catalyst rather than a lower portion thereof as shown regeneration gas after passing through suitable cyclone separators not shown and positioned in an upper portion of the regenerator passes into a plenum chamber not shown and then out the top of the regeneration vessel through opening 24 to line 17 the catalyst distributor of the present invention is generally referenced with numeral 22 spent catalyst is collected in a vertically extending hopper 26 from catalyst inlet conduit 4 and fluidized with an air distributor 28 fig4 illustrates enlarged details of the air distributor 28 the hopper air distributor 28 receives gas from through a conduit 31 that passes through the regenerator wall 47 and the side of the hopper 26 a plurality of conduits 33 may extend horizontally from the conduit 31 to provide a grid located at the bottom of the hopper 26 gas may then pass out through holes 103 or nozzles along the bottom surface of the conduits 33 and.