Operating method for fluid catalytic cracking involving alternating feed injection

摘要

The present invention is directed to a Fluid Catalytic Cracking process conducted under fluid catalytic cracking conditions by injecting into at least one reaction zone of a fluid catalytic cracking unit (FCCU) having one or more risers, a plurality of feeds wherein said plurality of feeds comprises at least one feed ( alpha ) and at least another feed ( beta ) wherein said feeds ( alpha ) and ( beta ) (a) differ in Conradson Carbon Residue by at least about 2 wt % points; or (b) differ in hydrogen content by at least about 0.2 wt %; or (c) differ in API gravities by at least about 2 points; or (d) differ in nitrogen content by at least about 50 ppm; or (e) differ in carbon-to-hydrogen ratio by at least about 0.3; or (f) differ in mean boiling point by at least about 200 DEG F; and wherein said feeds ( alpha ) and ( beta ) are alternately injected and wherein said alternate injection maintains said risers in a cyclic steady state, while the rest of the FCC unit is in a steady state.