Abstract: The characteristics of deep catalytic cracking (DCC) and enhanced deep catalytic cracking (DCC-plus) technology and their relationships were reviewed. DCC-plus technology has higher propylene yield than DCC technology, and the yield of dry gas and coke is significantly reduced. For a set of 2.2 Mt/a DCC-plus unit for processing 50% atmospheric residue mixed with 50% hydrocracking tail oil as feedstock, the yields of ethylene and propylene yields were 5.6% and 21.5%, respectively. A set of 1.2 Mt/a DCC-plus unit has switched between two operation modes of fuel oil program and olefins program. Compared with the fuel oil mode, the propylene yield was increased by 125.8%, and the DCC naphtha and light cycle oil (LCO) yields were reduced by 37.4% and 20.0%,respectively,under the olefins production mode. DCC technology is mature and reliable, and the large-scale and long-term operation of DCC unit has been verified in industry. For chemical refineries with the DCC units as the core, the oil product ratio (the total output of gasoline, diesel and aviation fuels as a proportion of crude oil processing) can be as low as 16.0%, and the rate of chemicals (the total production of propylene, aromatics and ethylene as a proportion of crude oil processing) is as high as 67.3%, which is a competitive technical choice for building a new generation of full chemical-type refinery.

Key words: deep catalytic cracking, feedstock adaptability, operation flexibility, large scale, long term, commercial verification