Patent ID: 8246914

Claim:
A fluid catalytic cracking system, comprising: a reaction zone comprising at least one riser containing a mixture of a first catalyst having pores with openings greater than about 0.7 nm and a second catalyst having smaller openings than the first catalyst provided by a conduit to the at least one riser, a source of a naphtha stream comprising about 20-about 70%, by weight, of one or more C5-C10 olefin compounds in fluid communication with the at least one riser via a naphtha line, a source of a C4 hydrocarbon stream in fluid communication with the at least one riser via a C4 line, and a source of a feed stream having a boiling point of about 180-about 800° C. in fluid communication with the at least one riser via a feed line; wherein a naphtha stream injection point on the at least one riser for the naphtha line is downstream of a C4 hydrocarbon stream injection point and a feed stream injection point on the at least one riser.