Maximum olefins production utilizing multi-stage catalyst reaction and regeneration

A method for increasing olefin production from a hydrocarbon feed, said method comprises:

• a) delivering from a multi-stage catalyst regenerator a partially-regenerated catalyst from at least one catalyst partial regeneration zone to a secondary riser reactor and a fully-regenerated catalyst from at least one catalyst full regeneration zone to a primary riser reactor;
• b) cracking the hydrocarbon feed in a first reaction zone of the primary riser reactor to produce a first cracked product including olefins and spent catalyst and passing the first cracked product and spent catalyst to a bed cracking reaction zone in a reactor vessel to produce a second cracked product;
• c) separating the first and second cracked products from the spent catalyst in the reactor vessel;
• d) recovering the first and second cracked products including olefins and separating an uncracked bottoms and a partially cracked product(s) from the cracked products;
• e) cracking a recycle feed comprising at least one of the uncracked bottoms, partially cracked, and cracked products of step (d), in the secondary riser reactor to produce a third cracked product and additional spent catalyst;
• f) separating and recovering the third cracked product comprising olefins from the additional spent catalyst and delivering the additional spent catalyst to the reactor vessel;
• and g) passing the spent catalyst from the reactor vessel to the multi-stage catalyst regenerator comprising the catalyst partial regeneration zone and the catalyst full regeneration zone, wherein the spent catalyst is partially regenerated to provide the partially-regenerated catalyst and a portion of the partially-regenerated catalyst is delivered to the catalyst full regeneration zone to provide fully regenerated catalyst.