Abstract: Due to heavy feedstock and increased coke production, the operation of the catalytic cracking unit of CNOOC Dongfang Petrochemical Co., Ltd. was limited. Based on this situation, the company has decided to use OMT-Ⅱ(R), a new generation of multistage porous molecular sieve DCC catalyst with high propylene and ethylene yield, developed by SINOPEC Research Institute of Petroleum Processing Co., Ltd. based on low coke technology platform. The results of commercial application showed that the yields of ethylene, propylene and LPG could be increased 0.44, 1.99 and 5.02 percentage points respectively when the catalyst OMT-II (R) occupied more than 85% of the mass of the system, and the yield of coke was decrease by 0.18 percentage point. At the same time, the yields of gasoline, diesel and oil slurry were decreased significantly.??It has achieved the target of significantly improving the cracking ability of heavy oil, reducing the coke yield, and successfully improving the comprehensive benefit of the DCC unit.

Key words: catalytic cracking, multi-stage porous molecular sieve, coke yield, propylene, liquid petroleum gas