Patent ID: 8877042

Claim:
A method of enhancing the conversion of a heavy oil feedstream derived from a crude distillation unit into a lighter hydrocarbon product stream consisting of ethylene, propylene, butylenes and gasoline, and the recovery of the lighter hydrocarbon products as a separate stream, the method comprising: a. directing a separate feedstream of the heavy oil into the top of an ancillary downflow reactor that contains fresh or regenerated hot catalyst of the same composition as the catalyst used in an FCC unit with which the downflow reactor is associated; b. introducing the heavy oil through a plurality of injection nozzles into a mixing zone and into contact with a controlled flow of the hot catalyst to provide a uniform mixture; c. operating the downflow reactor with a residence time of the heavy oil and Catalyst mixture in a reaction zone of from 0.1 seconds to 5 seconds at an operating temperature in the range of 990° F. to 1300° F. and with a catalyst-to-heavy oil ratio in the range from 25:1 to 50:1 by weight to produce the lighter hydrocarbon reaction products by cracking the heavy oil feedstream; d. separating the lighter hydrocarbon reaction product stream produced in the downflow reactor cracking process from spent catalyst downstream of the reaction zone; e. recovering the lighter hydrocarbon reaction product steam produced in the downflow reactor cracking process from spent catalyst in a rapid separation section that is downstream of the reaction zone; f. recovering the lighter hydrocarbon reaction products as a separate stream; and g. combining and commingling the spent catalyst from the downflow reactor with spent catalyst from the FCC unit and regenerating the combined spent catalysts for reuse in the FCC unit and the downflow reactor.