In this paper

the two-stage riser fluidized catalytic cracking technology (TSRFCC) is proposed aiming at improving the performance and overcoming the disadvantages of the ordinary one-stage riser FCC technology (OSRFCC).The distinct features of TSRFCC are attributed to catalyst relay and sub-section reaction. Daqing VGO mixed by 65% VR as feedstock and ZC-7300 catalyst were used to test the feasibility and superiority of the TSRFCC technology.A series of experiments were carried out in a pilot unit.By analyzing the abundant experimental data

the following conclusions can be reached: compared to OSRFCC technology

in the condition of similar conversion of heavy oil feedstock

TSRFCC can increase diesel oil yield by 6—8 percentage point

and light oil yield by 1—2 percentage point.Gasoline octane number also increases. TSRFCC shows the great potential and superiority in increasing diesel oil yield and improving product distribution and quality.