Industrial investigation on feasibility to raise near zero sulfur diesel production by increasing fluid catalytic cracking light cycle oil production

Abstract

Evaluation of opportunity to raise Euro V diesel production by increasing fluid catalytic cracking (FCC) light cycle oil (LCO) production was carried at the Lukoil Neftochim Bourgas, Bulgaria (LNB) refinery. The FCC LCO (IBP-360°C) production was investigated in the FCC conversion range between 69 and 83wt.% and LCO initial boiling point (IBP) between 177 and 210°C. It was found that the LCO yield increased from 16.0 up to 20.7wt.% by decreasing conversion from 83 to 69wt.%. At constant conversion in the FCC unit of 79.7wt.% the LCO yield increased from 17.8 to 24.8wt.% by decreasing the IBP from 210 to 177°C. A further 3.5wt.% LCO yield increase and meeting the diesel flash point specification of 55°C can be achieved by lowering the LCO IBP down to 163°C. It was found that during hydrotreatment of a blend of the LNB middle distillates and LCO in a high pressure (70bars) hydrotreater employing Co-Mo catalyst the maximum LCO (IBP=210; FBP=300°C) content that allows meeting the EN specifications is 10wt.%. If the LCO IBP is reduced to 177°C then the maximum LCO content in the feed can reach 20wt.%. The limitation of density not higher than 0.845g/cm3 in the hydrotreated product at 15°C is the restriction for further increase of LCO content in hydrotreater feed. Replacing the Co-Mo catalyst by Ni-Mo and noble metal catalysts in the high pressure hydrotreater can allow more than double increase of LCO content in hydrotreater feed. Hydrogen chemical consumption in that case, however is also more than twofold.