Method and apparatus for regenerating cracking catalyst

A fluid catalytic cracking process which takes place in a fluid catalytic cracking apparatus, said apparatus comprising:

• a reactor vessel and a regenerator vessel, said reactor vessel comprising a reactor riser means and a separation means for separating products of a catalytic cracking reaction from spent catalyst, said regenerator vessel comprising a bed of spent catalyst, placed substantially in the center of said regenerator vessel, and a bed of regenerated catalyst, placed substantially concentrically about said bed of spent catalyst, a means of recycling at least a portion of said regenerated catalyst from said regenerated catalyst bed to said spent catalyst bed and a regenerating medium inlet conduit cooperating with a regenerating medium distribution means in the lower section of said spent catalyst bed, wherein:
• said bed of spent catalyst is substantially completely separated from said bed of regenerated catalyst by a substantially annular wall means;
• said bed of spent catalyst further comprises a riser in the upflow section of said bed of spent catalyst;
• and
• said means of recycling at least a portion of said regenerated catalyst from said regenerated catalyst bed to said spent catalyst bed comprises at least one trickle valve means placed in said annular wall means,
• said process comprising the steps of:
• (i) passing a hydrocarbonaceous feed and catalyst admixed therewith through said reactor riser means, thereby effecting cracking of the hydrocarbonaceous feed at the process temperature under exothermic process conditions and deactivating the catalyst by deposition of carbon-containing material thereon;
• (ii) separating the deactivated catalyst from the cracked hydrocarbonaceous feed;
• (iii) fluidizing the spent catalyst with a regenerating medium and passing the deactivated catalyst to said regenerator vessel wherein the carbon-containing material is removed from the deactivated catalyst, thereby regenerating and heating the catalyst, recycling a portion of said regenerated catalyst into said spent catalyst bed through said trickle value means;
• and
• (iv) passing the regenerated hot catalyst to said reactor riser.