Possible ways to achieve deep HDS of light cycle oil

LCO from FCC is hard to be desulfurized due to its much higher aromatic content than straight run gas oil. Possible ways to achieve deep desulfurization of LCO, such as splitting of LCO and desulfurization of each fractions, lowering the cut point of LCO below boiling point of 4,6-DMDBT, and blending the low boiling point LCO into LGO, were presented. After 2 hr reaction at 360°C over NiMo catalyst, HDS of LCO 300- was nearly completed to give < 5 ppm S. NiMo catalyst was more active than CoMo in HDS of LCO, while in HDS of HCO CoMo provided higher sulfur removal than NiMo catalyst. Superiority of NiMo catalyst in HDS of LCO was believed to be from its higher hydrogenation activity and acidity, which was effective in removing the strongly adsorbed aromatic species and refractory sulfur species. Blending of LCO into LGO retarded HDS even with small amount, in particular over CoMo catalyst.