Abstract: In a pilot riser catalytic cracking unit, conventional heavy oil cracking catalyst VRCC was selected to investigate the cracking reaction performance and the SO2 content of regenerated flue gas of heavy oil feeds with different hydrogenation depths under the same experimental conditions. The results showed that with the increase of hydrogenation depth of raw materials, the concentration of SO2 of regenerated flue gas decreased from 526 mg/m3 of mild hydrogenated feed to 232 mg/m3 of deep hydrogenated feed. Compared to mild hydrogenated feedstock, using moderate hydrogenated feedstock,the LPG yield increased by 1.40 percentage points, the gasoline yield increased by 0.89 percentage points, the slurry yield decreased by 2.05 percentage points, and the total liquid product yields increased by 1.54 percentage points. Considering both the difficulty of hydrogenation of raw materials and the influence range on SOx emission of regenerated flue gas, selecting moderate hydrogenated feed for FCC can not only reduce the cost of hydrogenation process, but also meet the dual requirements of FCC on product distribution optimization and reduction of SOx emission of regenerated flue gas.

Key words: catalytic cracking, hydrogenation feedstock, flue gas, SOx emission